1,280 Matching Annotations
  1. Nov 2016
    1. S. Cole, J. R. Cole, G. A. Simon, Science 214, 881–886 (1981).

      This article is about one negative effect of peer review, that an individual scientist devotes so much time and energy to getting financial support that it takes away from their science.

      Basically, a huge disadvantage of the peer review program is that scientists must spend too much time writing what they intend to research, rather than performing the research.

    2. B. Alberts, M. W. Kirschner, S. Tilghman, H. Varmus, Proc. Natl. Acad. Sci. U.S.A. 111, 5773–5777 (2014).

      Bruce Alberts, Marc W. Kirschner, Shirley Tilghman and Harold Varmus describe the advances in scientific knowledge and human health that have accrued as a result of the long-standing public investment in biomedical research.

  2. Oct 2016
      • 5:48 Expert Political Judgment

        • Discusses the concept of Integrative Complexity
          • People with a lot of integrative complexity are more capable of reasoning about complex issues, distinguishing between facts and opinions, and seeing the world clearly as it is.
            • People who lack this quality tend to think in terms of black-and-white, and to have an arrogant and antagonistic attitude.
            • Fame is inversely correlated with integrative complexity
      • 11:29 The Big Sort by Bill Bishop

        • There is an ongoing trend, especially on the Internet, but also geographically, for people to cluster based on their own worldview, while they become less and less open to different ideas.
          • The content filtering mechanisms of Tumblr and other social media websites, where you can simply unfollow whoever you disagree with, are the reason why this phenomenon is so prevalent on the Internet.
      • 14:20 Pan's Labyrinth
        • Moral parable with "think for yourself; don't just blindly obey" as its message.
    1. - "Doing good (high quality work) matches with doing well (achieving wealth and professional advancement) in the field." -

      What's the source?

    2. a whole new field called positive psychology
    3. - "People are very bad at predicting what will bring them happiness." -

      What's the source?

    4. to quote Notorious B.I.G. - "Mo money mo problems"
    5. "The Happiness Hypothesis" by Jonathan Haidt
    6. http://en.wikipedia.org/wiki/Positive_psychology
    1. the demon scrupulously takes part in all these matters, sees all things, understands all things, and dwells in the most profound recesses of the mind, in the place of conscience.  He of whom I speak is entirely our guardian, our individual keeper, our watcher at home, our own proper regulator, a searcher Into our inmost fibres, our constant observer, our inseparable witness, a reprover of our evil actions, an approver of our good ones; if he is becomingly attended to, sedulously examined and devoutly worshipped, in the way in which he was worshipped by Socrates in justice and in innocence; he is our forewarner in uncertainty, our monitor in matters of doubt, our defender in danger, and our assistant in need. He is able also by dreams, and by tokens, and perhaps even openly, when necessity demands it, to avert from you evil, to increase your blessings, to aid you when depressed, to support you when falling, to lighten your darkness, to regulate your prosperity, and modify your adversity.

      This part is quoted in a talk on the Thelemic concept of Holy Guardian Angel here.

    1. the daemon who presides over you inquisitively participates of all that concerns you, sees all things, understands all things, and in the place of conscience dwells in the most profound recesses of the mind [see note 6]. For he of whom I speak is a perfect guardian, a singular prefect, a domestic speculator, a proper curator, an intimate inspector, an assiduous observer, an inseparable arbiter, a reprobater of what is evil, an approver of what is good; and if he is legitimately attended to, sedulously known, and religiously worshipped, in the way in which he was reverenced by Socrates with justice and innocence, will be a predictor in things uncertain, a premonitor in things dubious, a defender in things dangerous, and an assistant in want. He will also be able, by dreams, by tokens, and perhaps also manifestly, when the occasion demands it, to avert from you evil, increase your good, raise your depressed, support your falling, illuminate your obscure, govern your prosperous, and correct your adverse circumstances.

      This part is quoted in a talk on the Thelemic concept of Holy Guardian Angel here.

    1. Some references made in this video:

  3. Sep 2016
    1. J. J. Palop, J. Chin, L. Mucke, Nature 443, 768 (2006).

      This review was written by members of the same lab in which Dr. Roberson did the work described in this paper.

      It outlines how the symptoms experienced by Alzheimer's patients seem to fluctuate constantly, suggesting that these symptoms cannot just be caused by dying neurons (which would result in symptoms that would get progressively worse).

      The authors discuss known changes in other proteins in the brains of Alzheimer’s patients and how these protein networks might work together to mediate symptoms of Alzheimer’s disease in the brain.

    2. K. SantaCruz et al., Science 309, 476 (2005).

      Santa Cruz and colleagues studied genetically modified mice that had a mutation in the human version of the tau gene, which caused those mice to get tau tangles like those seen in Alzheimer’s disease.

      Knocking out this tau gene allowed the mice to avoid memory and cognitive problems, although the tangles still formed.

    3. A. J. Myers et al., Hum. Mol. Genet. 14, 2399 (2005).

      Myers and colleagues examined patients that had died of progressive supranuclear palsy, a disease caused by a mutation in the tau gene.

      They found that these patients also had an increased risk for Alzheimer’s disease, pointing to an important connection between tau and Alzheimer’s.

    4. R. Tanzi, L. Bertram, Cell 120, 545 (2005).

      Tanzi and Bertram review the "amyloid hypothesis," which is the idea that a build-up of amyloid-β into plaques causes problems in tau, which then form tangles, causing the symptoms of Alzheimer’s disease.

    1. G. D. Gilfillan et al., Am. J. Hum. Genet. 82, 1003 (2008)

      This study was about mutations in the SLC9A6 gene, which are related with neurological diseases, such as X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome.

      By using the experimental methods of linkage analysis and DNA sequencing they found out that a deletion in the SLC9A6 gene, encoding the Na(+)/H(+) exchanger NHE6, is basically responsible for these symptoms.

    2. M. L. Jacquemont et al., J. Med. Genet. 43, 843 (2006)

      M. L. Jacquemont worked on the genetic heterogeneity of syndromic autism, more easily revealed through array-CGH. The author suggested that this method should be prioritized in order to diagnose autism. This study also revealed that patients with locus duplications are less affected that those presenting deletions. Finally, the importance of the chromosomal imbalance has no direct relation with the severity of the mental retardation.

    3. J. Sebat et al., Science 316, 445 (2007).

      Sebat and colleagues worked on the involvment of de novo Copy Number Variations in autism.

      They showed that specific CNVs were mostly present in only one family among the tested group. They were also able to show the difference between simplex families, where autism is the result of spontaneous mutation and multiplex, where autism is most likely inherited.

    4. J. A. Vorstman et al., Mol. Psychiatry 11, 1 (2006).

      Vorstman provides a review of much of the recent cytogenetic studies on autism. In these studies, researchers were able to identify abnormalities by looking at the shapes and sizes of chromosomes. From these observations, they were able to deduce if there were large-scale deletions, repetitions, or inversions in the chromosomes. A small percentage (about 3%) of autistic patients had mutations like this. Vorstman gathers these findings into one article and proposes regions scientists should focus on in future research.

    5. P. Szatmari et al., Nat. Genet. 39, 319 (2007).

      P. Szatmari and colleagues have shown that copy number variants (CNV) were risk factors and causal events for autism. However, they are not the only parameters to be taken into account : oligogenic inheritance - inheritance of genes which, in a small quantity, code major changes - would be a prevalent factor of autism.

    6. R. Canitano, Eur. Child Adolesc. Psychiatry 16, 61 (2006)

      In this article, R. Canitano emphasizes the link between autism and epilepsy, showing that seizures are more frequent when mental retardation is associated with autism. The rate of comorbidity - cohabitation between two diseases, autism and epilepsy here - is estimated at 20-25%, meaning that this amount of autistic people is victim of seizures. This link has to be taken into account when considering therapy.

    7. E. Fombonne, J. Autism Dev. Disord. 33, 365 (2003).

      E. Fombonne has provided a review of epidemiological surveys on autism, in order to draw general conclusions. He concluded that autism is associated with mental retardation in about 70% of the cases and is overrepresented amongst males. He also showed that social class has no impact on the incidence of the disease. He also considered that available surveys did not allow to conclude that race or ethnicity influence the incidence of autism. Finally, no data could support the idea of secular evolution in the incidence of the disease.

    8. N. Risch et al., Am. J. Hum. Genet. 65, 493 (1999).

      Risch and colleagues studied the genetic makeup of subjects affected by autism.

      They showed that autism is most likely caused by multiple genes and identified several genes that could play a part in this disease in different individuals.

    9. A. E. West, E. C. Griffith, M. E. Greenberg, Nat. Rev. Neurosci. 3, 921 (2002).

      This study was about the regulation of specific transcription factors by neuronal activity. They found out, by using techniques as mass spectrometry and chromatin immunopreuritation, that synaptic activity determines the expression of a set of neural gene products.

      In this study also, a large nuclear protein, Cabin 1 (calcineurin-binding protein), was found out to be q cqlcium-regulated depressor of MEF2 activity.

    10. G. A. Cox et al., Cell 91, 139 (1997)

      This study was about a spontaneous mouse mutant, called slow-wave epilepsy (swe), which is related to several neurological syndromes, like ataxia, as well as about a unique epilepsy phenotype, that is characterized by 3/sec absence and tonic-clonic seizures.

      swe was fine-mapped on Chromosome 4 and identified as a null allele of Nhe1, which is the Na+/H+ exchanger, a ubiquitous, and acts as an integral membrane protein involved in pH regulation. It removes intracellular acid, exchanging a proton for an extracellular sodium ion.

    1. J. Celichowski, K. Grottel, Acta Neurobiol. Exp. (Warsz.) 58, 47–53 (1998).

      The aim of this study was to show the influence of two stimuli (produced in a short time sequence and called doublet) on the time where a tetanus was observed. By using single motor units of rats, it was shown that the doublet induced an increase of the tetanic tension and fusion. Also that slow motor units showed higher reaction to the doublet sensitivity than fast units.

    2. F. E. Zajac, J. L. Young, J. Neurophysiol. 43, 1206–1220 (1980).

      Researchers took muscle samples from cats and tried different tetanus on them. They seem to have found the efficient pulse and frequencies by the motor neuron to generate a optimum muscle tension.

    3. J. R. Gallant et al., Science 344, 1522–1525 (2014).

      They investigated the evolution of the electric organs of eels. They looked at the DNA of the electric eels and two other species with electric organs. They detected many different genes for the developement of electric organs. Their results show that despite big differences in the electric cells of the investigates species, they have leveraged similar transcription factors and developmental and cellular pathways in the evolution of electric organs.

    4. S. Hagiwara, T. Szabo, P. S. Enger, J. Neurophysiol. 28, 775–783 (1965).

      Some electrical fish produce not enough voltage to get an offensive or defensive meaning. In this study, authors try to understand in which this sorts of fish use this system. It will be demonstrate that it is used as direction and finding of the fish.

    5. K. K. Pedersen, O. B. Nielsen, K. Overgaard, Physiol. Rep. 1, e00026 (2013).

      Effects of high‐frequency stimulation and doublets on dynamic contractions in rat soleus muscle exposed to normal and high extracellular

    6. R. Hennig, T. Lømo, Nature 314, 164–166 (1985)

      By recording firing pattern in motor units of rats, authors demonstrates quantitatively that, contractile properties of the muscular system is improve by the tree different respond allowed (fast but easily fatigued, slow but fatigue resistant, both). Also this paper in studying and recording the normal value of muscular contraction of an healthy rats, will allow the searcher to notice if is somethings wrong or interact with the motor control system. Like in our articles where the Eels's electricity make the muscular system of the fish goes off. "Firing patterns of motor units in normal rats"

    7. G. M. Westby, Behav. Ecol. Sociobiol. 22, 341–354 (1988).

      The researchers investigated the behaviour of electric fish in french guiana. Notably, they describe in first the prey-capture behaviour of the electric eels.

    8. J. Keesey, J. Hist. Neurosci. 14, 149–164 (2005).

      Fish electric organs seams to be derived originally from muscle therefore a source of acetylcholine receptor. The Eels' anatomy was used many in different science domain such as Anatomy, embryology, and physiology. In previous research it was shown that the pathway between the nerve and electric organ used acetylcholine receptor. This is why this species, source of acetylcholine, conduct to very detailed studies by biochemist and neurologist.

    9. S. Finger, M. Piccolino, The Shocking History of Electric Fishes: From Ancient Epochs to the Birth of Modern Neurophysiology (Oxford Univ. Press, Oxford, 2011), p. 5.

      "The Shocking History of Electric Fishes: From Ancient Epochs to the Birth of Modern Neurophysiology" is a book written by Stanley Finger and Marco Piccolino. In this study they follow different types of animal (flat torpedo rays, the electric catfishes, and the "eel" of our article). All three are able to produce electricity shocks and explain how they helped to change the sciences and medicine.

    10. H. Grundfest, Prog. Biophys. Biop. Chem. 1957, 1–85 (1956)

      By studying the electroplaques of Torpedo-nobilian, the researcher try to understand how depolarising or hyperpolarizing changes in membrane potential occur. Furthermore they relief the latency time during stimulation of the nerve and the polarisation of the cells.

    1. W. R. Kerr, The ethnic composition of US inventors, Working Paper 08-006, Harvard Business School (2008)

      This study applies an ethnic-name database to individual patent records granted by the United States Patent and Trademark Office to document these trends with greater detail than previously available.

    2. D. F. Horrobin, JAMA 263, 1438–1441 (1990).

      The main goal of peer review in the biomedical sciences is to facilitate the introduction into medicine of improved ways of curing, relieving, and comforting patients. The achievement of this aim requires both quality control and the encouragement of innovation. If an appropriate balance between the two is lost, then peer review will fail to reach its purpose.

    1. R. B. Widelitz, T.-X. Jiang, J. Lu, C.-M. Chuong, b-catenin in epithelial morphogenesis: Conversion of part of avian foot scales into feather buds with a mutated b-catenin. Dev. Biol. 219, 98–114 (2000).

      This paper explored the role of β-catenin (protein involved in growth and thought to be a morphogen) which is expressed in the placode.

      It was found that when this protein was mutated, the chickens would be scaleless(on the feet) and have abnormal feather growth.

    2. C. Blanpain, E. Fuchs, Epidermal stem cells of the skin. Annu. Rev. Cell Dev. Biol. 22, 339–373 (2006).

      The development of skin cells that give rise to hairs is reviewed in this paper.

      A hair placode forms which allow for the expression of genes that determine skin cells and hair follicle development.

    3. D. Dhouailly, A new scenario for the evolutionary origin of hair, feather, and avian scales. J. Anat. 214, 587–606 (2009).

      This paper proposed the theory that mammal hairs evolved from glandular structures. Whereas reptiles and birds skin (including feathers and scales) evolved a different pathway where a thick protective covering which would become scales.

    4. P. F. A.Maderson,Mammalian skin evolution: A reevaluation. Exp. Dermatol. 12, 233–236 (2003).

      This review deals with a model of how hair evolved, updating a model built in the 1972 (reference 3).

      This model supposes that the development of hair was caused by mutations in patterning genes. this development allowed hair to become useful insulation.

    5. M. C. Milinkovitch, L. Manukyan, A. Debry, N. Di-Poï, S. Martin, D. Singh, D. Lambert, M. Zwicker, Crocodile head scales are not developmental units but emerge from physical cracking. Science 339, 78–81 (2013).

      This paper illustrates the way that crocodile head scales form. the process is different to the formation of other skin traits (such as feathers, hair and other scales).

      The crocodile face and jaw scales are formed through the force of the growing cells physically pushing and cracking about hard shell forming unique patterns.

    1. J. B. Silk, in The Oxford Handbook of Evolutionary Psychology, R. I. M. Dunbar, L. Barrett, Eds. (Oxford Univ. Press, Oxford, 2007), pp. 115–126.

      Chapter 10: Empathy, sympathy, and prosocial preferences in primates.

      There are several potential lines of evidence for the existence of empathy in nonhuman primates. Because of the subjectivity in interpretation of animals' intentions as well as no defined assay for empathy or sympathy, "we cannot be certain whether any given interpretation is right or wrong."

      "To transform singular observations of behavior into more robust findings we need to develop theoretically grounded hypotheses that we can subject to empirical testing."

      http://www.amazon.com/Oxford-Handbook-Evolutionary-Psychology-Handbooks/dp/0199561788

    2. although skeptics remain (27)

      "Current claims for the existence of empathy, sympathy, and moral sentiments and other-regarding preferences in other primates rest on an insecure empirical foundation.

      The anecdotal accounts have limited value because they rely on subjective interpretation of animals' intentions and motivations and they are not systematically collected or analysed.

      This means we cannot be certain whether any given interpretation is right or wrong and we have no means of discriminating against competing claims."

      The chapter covering this controversial view of whether nonhuman animals display empathy may be found here:

      http://www.amazon.com/Oxford-Handbook-Evolutionary-Psychology-Handbooks/dp/0199561788

      Type the word empathy into the "search inside this book" window.

    3. Initially, rats in the trapped condition opened the door in any of three ways: tipping the door over from the side or top or pushing it up with their heads

      From materials and methods: Measuring opening style: Each door opening was classified to indicate how the door was opened.

      Three types of opening were observed:

      1) Rats opened the door by nudging it up with their head from the front of the restrainer (“head”),

      2) rats opened the door by leaning on the heavy side of the door (“side”), or

      3) rats opened the door by standing on top of the door (“top”).

    4. D. Drai, I. Golani , SEE: A tool for the visualization and analysis of rodent exploratory behavior. Neurosci. Biobehav. Rev. 25, 409 (2001).

      This paper describes the patterns rodents take while exploring their environment using a computational method of analysis. SEE allows for the distinction between stopping and progressing, spatial spread, dynamics of space occupancy, number of stops per excursion, and the maximal speeds attained.

      [http://www.sciencedirect.com/science/article/pii/S0149763401000227]

    5. G. E. Rice, P. Gainer , “Altruism” in the albino rat. J. Comp. Physiol. Psychol. 55, 123 (1962)

      The authors tested whether albino rats could display altruistic characteristics. They defined altruism as "behavior of one animal that relieves another animal's 'distress.'"

      The distress-causing paradigm was using a harness to suspend one rat free from the floor. The second rat is free in a separate compartment and can see and hear the suspended rat.

      The second rat can bring the suspended rat down to the floor by pressing a lever, and did so significantly more than if there was a styrofoam block being suspended.

      These results do point toward rats being capable of altruistic behavior because the rats performed an action that was not beneficial to itself, but that benefits one of its species.

    6. D. J. Langford et al ., Social approach to pain in laboratory mice. Soc. Neurosci. 5, 163 (2010).

      These authors tested whether the purpose of pain expression is to attract comfort or receive aid from conspecifics.

      For this they assayed the likelihood of a free mouse to approach/contact a jailed mouse experiencing pain versus a jailed mouse unaffected by pain.

      This hypothesis was true in the case of female mice but not male mice. However the observer female mice only approached mice that were "known" (i.e., had previous contact with the observer mouse). Thus there is sex specificity to the social approach to pain in laboratory mice.

      The contact made by the free mouse with the mouse in pain resulted in less pain behavior.

    7. R. M. Church , Emotional reactions of rats to the pain of others. J. Comp. Physiol. Psychol. 52, 132 (1959).

      The authors of this paper measure the reaction one group of rats has to the outward show of pain of another rat receiving an electric shock.

      One group of rats had lever pushing for food associated with the electric shock of another rat and a shock to themselves (paired shock). A second group had lever pushing for food associated with only themselves receiving a shock (unpaired shock). The third group received no shock when they pushed the lever for food (no shock).

      The authors then measured the frequency of lever pushing by spectator rats from all three groups (paired shock, unpaired shock, and no shock) in response to shock delivery to the tester rat.

      Rats trained in the paired shock paradigm reacted by significantly less lever pushing compared with the no shock group.

      This suggests that the responses given by the paired shock group may be a result of conditioning rather than that action being a show of sympathy.

    8. J. Decety, P. L. Jackson , The functional architecture of human empathy. Behav. Cogn. Neurosci. Rev. 3, 71 (2004)

      In this review, the authors note that "Empathy involves not only any sentimentally commanded encounters with another person’s actual or inferred emotional state but also some minimal recognition and understanding of another’s emotional state."

      They also highlight the main components of empathy: shared neural representations, self-awareness, mental flexibility, and emotion regulation.

      These components are used together to form a model to predict empathy deficits in social and neurological disorders.

    9. (20–26)

      de Waal et al.

      The authors looked at consolation behavior in chimpanzees. Consolation is ranked under the same umbrella as empathy. In their paper it was defined as "an interaction in which an uninvolved bystander initiates friendly contact with a recent victim of aggression."

      Main finding: The empathy hypothesis that states that consolation is more likely to occur among animals that are socially close was supported.

    1. F. Soliman et al., Science 327, 863 (2010)

      This is a very interesting paper showing that a single-nucleotide polymorphism in the BDNF gene can impair the extinction of a conditioned fear response in both humans and mice. This polymorphism is also associated with anxiety-related behavior and atypical frontoamygdala activity in humans.

      This is important because it suggests that the variant allele may affect the efficacy of exposure therapy, which relies on the process of extinction.

    2. R. Garcia, G. Spennato, L. Nilsson-Todd, J. L. Moreau, O. Deschaux, Neurobiol. Learn. Mem. 89, 560 (2008).

      The goal of this study was to examine the effects of chronic mild stress on hippocampal and medial prefrontal cortex potentiation and extinction memory in rats.

      The authors found that chronic mild stress did not interfere with the extinction of fear, but did impair the recall of extinction.

      They found that chronic mild stress interfered with the development of extinction-related potentiation in the hippocampal/medial prefrontal cortex pathway.

    3. S. A. Heldt, L. Stanek, J. P. Chhatwal, K. J. Ressler, Mol. Psychiatry 12, 656 (2007).

      In this study, the BDNF gene was deleted from the hippocampi of mice. This impaired the animals' ability to recognize new objects, learn spatial orientation, and extinguish conditioned fear.

      These cognitive impairments are also found in anxiety disorders, suggesting that BDNF in the hippocampus may play a role in anxiety and depression.

    4. J. P. Chhatwal, L. Stanek-Rattiner, M. Davis, K. J. Ressler, Nat. Neurosci. 9, 870 (2006).

      This is a very interesting article showing that BDNF, acting through the tyrosine kinase B receptor, is required for the consolidation of stable extinction memories.

    5. W. A. Falls, M. J. Miserendino, M. Davis, J. Neurosci. 12, 854 (1992).

      This is an older paper that was one of the first to show that fear extinction may be an NMDA-dependent process by infusion an NMDA antagonist (AP5) into the amygdala and measuring fear potentiated startle.

    6. A. Burgos-Robles, I. Vidal-Gonzalez, E. Santini, G. J. Quirk, Neuron 53, 871 (2007).

      This paper shows that infusion of CPP, which is an NMDA receptor antagonist, into the ventromedial prefrontal cortex can impair extinction recall.

    7. C. R. Bramham, E. Messaoudi, Prog. Neurobiol. 76, 99 (2005).

      Here, the authors review current research describing the role of BDNF in long-term potentiation, and its known molecular mechanisms.

    8. T. W. Bredy et al., Learn. Mem. 14, 268 (2007).

      In this paper, the authors examine how epigentic gene expression regulation of BDNF enables fear extinction.

    9. F. Sotres-Bayon, L. Diaz-Mataix, D. E. Bush, J. E. LeDoux, Cereb. Cortex 19, 474 (2009).

      This paper investigates the role of NR2-containing N-methyl-D-aspartate receptors in the ventromedial prefrontal cortex and lateral amygdala in the consolidation of fear extinction memories.

    10. F. Sotres-Bayon, C. K. Cain, J. E. LeDoux, Biol. Psychiatry 60, 329 (2006).

      In this paper, the authors examine research that has led to the notion that the medial prefrontal cortex is a critical component in both emotional regulation and fear extinction.

  4. Aug 2016
    1. Given the 51 tons of ivory seized in 2013, the number of elephants killed that year could have exceeded 50,000, out of an estimated 434,000 elephants remaining (4)

      How does the author estimate the number of elephants killed based on the weight of seized ivory?

      It's known that only about 10% of all smuggled goods, such as ivory, drugs, or weapons, are caught by customs. So if 51 tons of seized ivory is only 10% of all poached ivory, the actual amount of all smuggled ivory should be 10 times as high, or about 510 tons (510,000 kilograms).

      510,000 kg of ivory corresponds to about 51,000 elephants.

    2. S. K. Wasser et al., Proc. Natl. Acad. Sci. U.S.A. 104, 4228–4233 (2007).

      In this study the authors used improved methods to identify the geographic origin of the largest ivory seizure since the 1989 ivory trade ban. They showed that the ivory was from savanna elephants from a narrow east-to-west band of southern Africa, centered on Zambia.

      The findings enabled law enforcement to focus their investigation to a smaller area and fewer trade routes. They also led the Zambian government to improve antipoaching efforts.

    3. S. K. Wasser et al., Proc. Natl. Acad. Sci. U.S.A. 101, 14847–14852 (2004).

      This earlier paper by the first author describes in greater detail how the genetic reference map was constructed. It also explains the statistical smoothing method that the authors used to assign a geographic location to seized ivory.

    4. A. L. Roca, N. Georgiadis, J. Pecon-Slattery, S. J. O’Brien, Science 293, 1473–1477 (2001).

      This paper shows that African elephants that live in forests are actually a different species than African elephants that dwell in the savanna. Until this paper, all African elephants had been grouped together as a single species.

      The authors proposed two species names: Loxodonta africana for the savanna elephants and L. cyclotis for the forest elephants.

    5. United Nations, The Globalization of Crime (United Nations Office on Drugs and Crime, New York, 2010); http://unodc. org/unodc/en/data-and-analysis/tocta-2010.html.

      This document is produced by the United Nations Office on Drugs and Crime. It analyzes a range of key transnational crime threats and offers a view of its global dimensions.

    6. K. S. Gobush, B. M. Mutayoba, S. K. Wasser, Conserv. Biol. 22, 1590–1599 (2008).

      This paper examined the long-term impact of poaching on elephant family structure, stress levels, and reproductive output approximately 15 years after the 1989 ivory ban was implemented. Before the ban, widespread poaching drastically altered the demographic structure of the African elephant family groups by decreasing the number of old adult female elephants.

      The authors specifically examined 218 adult female African elephants from 109 groups that differed in size, age structure, and average genetic relatedness.

      Females from groups that lacked an old matriarch, first-order relatives, and strong social bonds had significantly higher stress hormone levels than females from groups where these features existed. Female elephants from groups disrupted by poaching had significantly lower reproductive output.

      The negative impact of poaching persisted 15 years after the 1989 ivory ban was implemented.

    1. enabling the drongo to steal the abandoned food (11,12)

      In this study, the authors demonstrated that drongos are heartless.

      Melissa can edit as SitC

  5. Jul 2016
    1. A. Jacob, L. Lefgren, Are idle hands the devil's workshop? Incapacitation, concentration, and juvenile crime. Am. Econ. Rev. 93, 1560–1577 (2003).

      Findings from this study suggest that when juveniles are not engaged in supervised activities they are more likely to engage in certain anti-social behaviors; at the same time, the increase in interactions associated with school attendance leads to more interpersonal conflict and violence.

    2. L. Lochner, E. Moretti, The effect of education on crime: Evidence from prison inmates, arrests, and self-reports. Am. Econ. Rev. 94, 155–189 (2004).

      Using Census and FBI data, this study finds that schooling significantly reduces the probability of incarceration and arrest.

    3. P. J. Cook, J. Ludwig, in Controlling Crime: Strategies and Tradeoffs, P. J. Cook, J. Ludwig, J. McCrary, Eds. (University of Chicago Press, Chicago, 2011), pp. 1–39.

      Controlling Crime considers alternative ways to reduce crime that do not sacrifice public safety. Among the topics considered here are criminal justice system reform, social policy, and government policies affecting alcohol abuse, drugs, and private crime prevention.

    4. W. J. Wilson, When Work Disappears: The World of the Urban Poor (Alfred Knopf, New York, 1996).

      In this book, W. J. Wilson persuasively argues that problems endemic to America's inner cities--from fatherless households to drugs and violent crime--stem directly from the disappearance of blue-collar jobs in the wake of a globalized economy

    5. E. I. Knudsen, J. J. Heckman, J. L. Cameron, J. P. Shonkoff, Economic, neurobiological, and behavioral perspectives on building America’s future workforce. Proc. Natl. Acad. Sci. U.S.A. 103, 10155–10162 (2006).

      This paper concludes that the most efficient strategy for strengthening the future workforce, both economically and neurobiologically, and improving its quality of life is to invest in the environments of disadvantaged children during the early childhood years.

    6. C. Uggen, Work as a turning point in the life course of criminals: A duration model of age, employment, and recidivism. Am. Sociol. Rev. 65, 529–546 (2000).

      A brief overview of research on the relationship between work and crime.

    7. Unemployment and criminal involvement: An investigation of reciprocal causal structures. Am. Sociol. Rev. 49, 398–411 (1984)

      This study showed that unemployment and crime mutually influence one another over the individual's life span.

    1. K. A. Oye, K. Esvelt, E. Appleton, F. Catteruccia, G. Church, T. Kuiken, S. B. Lightfoot, J. McNamara, A. Smidler, J. P. Collins , Regulating gene drives. Science 345, 626–628 (2014).

      This and the subsequent reference discuss the concept of and the dangers associated with gene drives.

      Gene drives are techniques that alter genes in such a way that biases their inheritance, making them spread more rapidly than normal through a population.

      Mutagenic chain reaction is an example of a powerful gene drive method. They list several checkpoints that they recommend be completed before the use of gene drive in endogenous populations, such as designing and testing techniques for reversal of the gene drive and long term studies to fully understand the consequences of a gene drive strategy.

  6. Jun 2016
    1. M. Rosel, C. Claas, S. Seiter, M. Herlevsen, M. Zoller, Oncogene 17, 1989 (1998).

      Describes how C4.4, a human GPI-anchored protein, was found.

    2. G. C. Fletcher et al., Br. J. Cancer 88, 579 (2003).

      Identifies hAG-2 and hAG-3 (nAG homologs) as ligands for C4.4, a GPI-anchored protein in humans.

    3. D. A. Thompson, R. J. Weigel, Biochem. Biophys. Res. Commun. 251, 111 (1998).

      hAG-2 (an nAG homolog in humans) is expressed alongside an estrogen receptor in breast-cancer cell lines. The authors propose that hAG may play some role in cancer.

    4. D. B. Drachman, M. Singer, Exp. Neurol. 32, 1 (1971).

      Acetycholine, a neurotransmitter for skeletal muscle, was once thought to be a molecule crucial in limb regeneration. However, this paper shows that when its release is inhibited, the limb still regenerates.

    5. K. Echeverri, E. M. Tanaka, Dev. Biol. 279, 391 (2005).

      Experiments showing the effects of Prod1 overexpression in regeneration are shown. Overexpression causes distal blastema cells to take on a proximal identity and disrupt proper limb patterning.

    6. S. Morais da Silva, P. B. Gates, J. P. Brockes, Dev. Cell 3, 547 (2002).

      This paper shows how Prod1 was discovered in salamanders and provides a basis for this paper, as nAG is ligand.

    7. M. Maden, Nature 295, 672 (1982).

      A research article that shows that vitamin A causes issues with the PD axis during regeneration of salamanders. This paper provides the basis for using vitamin A and other retinoids to disrupt proper limb regeneration.

    8. J. P. Brockes, Science 276, 81 (1997).

      A good overview of limb regeneration, specifically in salamanders. Discusses some molecular mechanisms in regards to limb specification and muscle regeneration.

    1. L. Hartwell, P. Szankasi, C. J. Roberts, A. W. Murray, S. H. Friend, Science 278, 1064 (1997).

      This article discusses the use of genetic profiling in tumors to determine the ideal course of treatment, something that has gained increasing attention as our sequencing technology improved.

    2. A. B. Niculescu et al., Mol. Cell. Biol. 18, 629 (1998).

      This article provided evidence that p21 might play a role in the G2-M checkpoint in addition to its established role at the G1-S checkpoint.

      Additionally, the paper looked at the protein Rb (retinoblastoma) and its role in checkpoint activation. Rb prevents cells from entering S phase when signals from growth factors are absent.

    3. Y. Li, C. W. Jenkins, M. A. Nichols, Y. Xiong, Oncogene 9, 2261 (1994).

      This paper showed that the levels of p21 normally oscillate throughout the cell cycle. However, in cells that did not have functional p53, no p21 was detected, implying that p21 expression is regulated by p53.

    4. A. Paoletti and M. Bornens, Prog. Cell Cycle Res. 3, 285 (1997).

      This paper discusses research on the process of centrosome duplication.

    5. K. Fukasawa, T. Choi, R. Kuriyama, S. Rulong, G. F. Vande Woude, Science 271, 1744 (1996).

      This paper established a role for p53 in the regulation of centrosomes, which enable the cell to separate its chromosomes during mitosis. Cells without functional p53 had abnormal numbers of centrosomes, leading to unequal chromosome segregation.

    6. S. Zhou et al., Proc. Natl. Acad. Sci. U.S.A. 95, 2412 (1998)

      This paper looked at the role of the protein SMAD4 in a pathway called TGF-β signaling. The authors used homologous recombination to disrupt the SMAD4 gene.

    7. H. Hermeking et al., Mol. Cell 1, 3 (1997).

      This article investigated the G2-M checkpoint in irradiated colorectal cancer cells and found that p53 induced the expression of a protein called 14-3-3, which triggers G2 arrest.

    8. D. P. Cahill et al., Nature 392, 300 (1998).

      This paper showed that mitotic checkpoints are often defective in cancer cells, leading to the chromosomal instability that may drive carcinogenesis (the development of cancer).

    9. T. J. McGarry and M. W. Kirschner, Cell 93, 1043 (1998).

      This paper described the protein geminin, which prevents DNA replication from occurring more than once per cell cycle. Geminin accumulates after DNA replication to block repeated replication, and it is degraded in mitosis so that the cell can replicate its DNA in the next S phase.

    10. P. L. Olive, J. P. Banath, R. E. Durand, Radiat. Res. 146, 595 (1996).

      This article looked into the survival of different cell lines treated with radiation. The authors observed the appearance of "giant cells" that had undergone extra rounds of replication, which in turn generated multiple nuclei.

    11. T. Waldman, C. Lengauer, K. W. Kinzler, B. Vogelstein, Nature 381, 713 (1996).

      This paper showed that when cells lacking p21 were treated with DNA-damaging agents, they frequently underwent extra rounds of replication, which led to deformed nuclei and cell death.

    12. J. P. Brown, W. Wei, J. M. Sedivy, Science 277, 831 (1997).

      This paper established a role for p21 in senescence, an age-dependent decline in the cell's ability to divide.

    13. T. Waldman, K. W. Kinzler, B. Vogelstein, Cancer Res. 55, 5187 (1995).

      This paper showed that p21 functioned downstream of p53 in the activation of the G1-S checkpoint.

    14. L. H. Hartwell and M. B. Kastan, Science 266, 1821 (1994); A. B. Niculescu et al., Mol. Cell. Biol. 18, 629 (1998)

      This review discusses what was known at the time about the regulation of the cell cycle and how we could potentially use this information to design new cancer drugs.

    1. M. A. Cuadros, J. Navascués, Prog. Neurobiol. 56, 173 (1998). 

      An early review of microglial origin in birds.

    2. P. Herbomel, B. Thisse, C. Thisse, Dev. Biol. 238, 274 (2001). 

      This study showed that invasion of embryonic tissue by yolk sac macrophages in zebrafish fails in the absence of macrophage colony-stimulating factor-1.

    3. I. M. Samokhvalov, N. I. Samokhvalova, S. Nishikawa, Nature 446, 1056 (2007).

      The authors of this study generated the RUNX1 fate mapping model used in this study and showed that yolk sac cells expressing Runx1 can develop into fetal lymphoid progenitors and adult hematopoietic stem cells (HSCs).

    4. G. Blevins, S. Fedoroff, J. Neurosci. Res. 40, 535 (1995).

      As shown in this paper, microglia are not affected by the autosomal recessive mutation osteopetrosis (op) that leads to a general skeletal sclerosis and decreased numbers of macrophages in various tissues.

    5. V. Chitu, E. R. Stanley, Curr. Opin. Immunol. 18, 39 (2006). 

      A review of the role of the colony-stimulating factor-1, also known as macrophage stimulating factor, in immunity and inflammation.

    6. F. Alliot, I. Godin, B. Pessac, Brain Res. Dev. Brain Res. 117, 145 (1999).

      This study suggested that microglia derive from yolk sac progenitors and actively proliferate in situ.

    7.  K. Liu et al., Science 324, 392 (2009); 10.1126/science.1170540. 

      This study examines the origin and differentiation of dendritic cells.

    8. S. H. Orkin, L. I. Zon, Cell 132, 631 (2008).

      A review of the developmental origins of hematopoietic stem cells and the molecular mechanisms that regulate lineage-specific differentiation.

    9. A. M. Lichanska, D. A. Hume, Exp. Hematol. 28, 601 (2000). 

      In this review of the studies on the origins, phenotype, and function of embryonic phagocytes the authors conclude that yolk sac–derived macrophages constitute a separate lineage.

    10. K. Liu et al., Nat. Immunol. 8, 578 (2007). 

      This study showed that limited recruitment of cells by the recipient in parabiotic models can be attributed to a short half-life of the donor-derived cells in the blood.

    11. A. Mildner et al., Nat. Neurosci. 10, 1544 (2007). 

      In this study the authors identified a unique population of peripheral Ly-6C(hi)CCR2(+) monocytes, which are preferentially recruited into the lesioned brain following irradiation.

    12. B. Ajami, J. L. Bennett, C. Krieger, W. Tetzlaff, F. M. Rossi, Nat. Neurosci. 10, 1538 (2007). 

      Using parabiosis and irradiation in an experimental autoimmune encephalitis mouse model of multiple sclerosis, the authors found that peripheral monocytes infiltrate the brain and contribute to the progression of the disease but do not contribute to the pool of resident microglial cells.

    13. L. J. Lawson, V. H. Perry, S. Gordon, Neuroscience 48, 405 (1992). 

      Yet another early study supporting the hypothesis of microglial turnover via division and recruitment of peripheral monocytes into the brain parenchyma in the absence of the overt blood-brain barrier disruption.

    14. E. A. Ling, J. Anat. 128, 847 (1979). 

      One of the earlier studies of microglial origin, supporting their monocytic origin.

    15. R. M. Ransohoff, V. H. Perry, Annu. Rev. Immunol. 27, 119 (2009). 

      This is a comprehensive review of the ontogeny and functions of microglial cells.

    1. M. Sinha et al., Science 344, 649–652 (2014).

      Similar to this study, which showed that a young systemic factor could improve neurogenesis in old mice, Sinha et al. 2014 tested the same concept in muscle.

      Exposure of GDF-11 in old mice led to improved muscle structure, restored genomic integrity in adult muscle stem cells, increased strength, and increased capacity for exercise.

    2. C. L. Grady et al., Neuroimage 8, 409–425 (1998).

      This study, conducted in 1999, was one of the first to study the effects of age on brain networks. At the time, little was known about the relationship between age and brain mechanisms of changes in memory.

      This study showed that age is related to changes in verbal memory, and not picture memory.

    3. L. Katsimpardi et al., Stem Cells 26, 1796–1807 (2008).

      Neurogenesis is restricted to two main areas of the brain (subventricular zone and dentate gyrus) by precursor cell proliferation and differentiation. BM88/Cend1 is a neuronal lineage specific regulator. In this study, Katsimpardi et al. studied the effects of this regulator in postnatal neurogenesis.

      They found that BM88 is important for cell cycle control and neuronal differentiation in the neonatal subventricular zone, in the transition from neuroblast to mature neurons in mouse brains.

    4. J. Luo, S. B. Daniels, J. B. Lennington, R. Q. Notti, J. C. Conover, Aging Cell 5, 139–152 (2006).

      Here, the authors study the subventricular zone (SVZ) to investigate the decline in neurogenesis during aging. By conducting electron microscopy imaging, and labeling cells, they examine the cytoarchitecture of the SVZ.

      They found a specific dorsolateral aspect of the SVZ, which retains features of a neurogenic stem cell niche in elderly mice.

    5. S. A. Villeda et al., Nature 477, 90–94 (2011).

      This study shows the effects of systemic factors on the decline of age-related neurogenesis. They found that chemokines CCL1/Eotaxin is present in aging mice, and is associated with reduced neurogenesis. Similar to this Katsimpardi et al. study, increasing the levels of the blood-borne factor CCL1 in young mice led to decreased neurogenesis and impaired learning and memory.

    6. H. van Praag, G. Kempermann, F. H. Gage, Nat. Neurosci. 2, 266–270 (1999).

      Exposure to an enriched environment increases neurogenesis in adult mice. Examples of enriched environments include larger housing, voluntary exercise, social interactions, and learning opportunities. Enhanced neurogenesis in enriched environments is also linked to improved spatial memory capabilities.

      This study shows that voluntary exercise alone can improve enhanced neurogenesis in adult mice.

    7. Q. Shen et al., Science 304, 1338–1340 (2004).

      Here, endothelial cells were identified as critical components of the neural stem cell niche.

      Factors derived from endothelial cells promote neural stem cell self-renewal and promotes neurogenesis.

    8. F. S. Loffredo et al., Cell 153, 828–839 (2013).

      Reference 13 describes a study similar to the one described in this paper, where heterochronic parabiotic mouse pairs were generated between young and old mice, to discover a reversal in the process of age-related cardiac hypertrophy.

      In this study, they observed a dramatic reduction in cardiac hypertrophy in old mice, due to being exposed to a blood-borne factor in young mice. In order to identify the special systemic factor, they profiled the proteome of young mice, and found that GDF11 declines with age, and exposure to GDF11 in old mice restored age-related cardiac hypertrophy.

    9. J. S. Snyder, A. Soumier, M. Brewer, J. Pickel, H. A. Cameron, Nature 476, 458 (2011).

      Reference 6 studies the effects of stress and anxiety on neurogenesis.

      Here, they found that a small subset of neurons in the dentate gyrus, which is responsible for the negative control of the hypothalamic-pituitary-adrenal axis. Elevation of stress hormones and anxiety are correlated with decreased neurogenesis.

  7. May 2016
    1. X. Zheng et al., Rev. Sci. Instrum. 83, 125001 (2012)

      This article reports the design of the high-resolution projection microstereolithography technique used by the authors.

      This technique is used in the present article to manufacture the different cellular solids (see Fig.2 A).

    2. W. Y. Jang, S. Kyriakides, A. M. Kraynik, Int. J. Solids Struct. 47, 2872–2883 (2010).

      The authors of this article investigated the compressive behavior of a random cell structure, a metallic foam.

      This structure was also manufactured by the authors of the present article and served for comparison purposes against the new ultralight and ultrastiff structures.

    3. J. D. Renton, Elastic Beams and Frames (Horwood, Chichester, UK, ed. 2, 2002).

      This book presents the basic theory and tools needed to study the behavior of elastic structures.

    4. V. S. Deshpande, N. A. Fleck, M. F. Ashby, J. Mech. Phys. Solids 49, 1747–1769 (2001).

      The goal of this article is to analyze the properties of the octet-truss unit cell using mechanical theory, simulations, and experiments.

      The octet-truss unit cell is the basic building block chosen by the authors of the present article to design their ultralight and ultrastiff materials.

    5. D. Rayneau-Kirkhope, Y. Mao, R. Farr, Phys. Rev. Lett. 109, 204301 (2012).

      In this article, the authors explain the process of manufacturing an ultralight fractal structure to obtain either hollow or solid objects. The potential applications are described.

    6. J. K. Cochran, K. J. Lee, D. McDowell, T. Sanders, Multifunctional metallic honeycombs by thermal chemical processing. In Processsing and Properties of Lightweight Cellular Metals and Structures, A. K. Ghosh, T. H. Sanders, T. D. Claar, Eds. (Minerals, Metals and Materials Society, Seattle, WA, 2002), p. 127–136.

      This chapter of a book describes the processing and the properties of a specific cellular class of solids: the metallic honeycombs.

    7. L. J. Gibson, MRS Bull. 28, 270–274 (2003).

      This text reviews the contents of a special issue of the MRS bulletin, dedicated to cellular solids.

    8. S. O. Kucheyev et al., Adv. Mater. 24, 776–780 (2012).

      This article describes the behavior of nanoporous silica aerogels: these objects are super compressible for ultralow densities.

    9. T. A. Schaedler et al., Science 334, 962–965 (2011)

      In this article, the authors have fabricated ultralight metallic microlattices and have performed mechanical testing on these objects.

      The elasticity of this material is proportional to the square of the density.

      Hence, the linear law desired by the authors of the present paper is not reached in this article.

    10. J. L. Gibson, F. M. Ashby, Cellular Solids: Structure and Properties (Cambridge Univ. Press, Cambridge, 2001).

      This book about cellular solids summarizes the theory needed to understand the structural properties and the mechanical behavior of cellular solids.

      The applications of these kinds of materials are also reviewed.

    11. S. Baudis et al., Biomed. Mater. 6, 055003 (2011).

      In this article, the authors report the design of a new biocompatible material in the vascular tissue engineering field.

    12. O. Y. Kwon, H. J. Ryu, S. Y. Jeong, J. Ind. Eng. Chem. 12, 306 (2006).

      This article describes the use of carbon microlattices as a catalyst support for chemistry applications.

    13. L. Valdevit, A. Pantano, H. A. Stone, A. G. Evans, Int. J. Heat Mass Transfer 49, 3819–3830 (2006).

      This article presents the optimization process in the design of metallic sandwiches for active cooling applications.

    14. T. A. Schaedler et al., Adv. Eng. Mater. 16, 276–283 (2014).

      This article describes the design of metallic microlattices for energy-absorbing applications.

    15. L. Valdevit, A. J. Jacobsen, J. R. Greer, W. B. Carter, J. Am. Ceram. Soc. 94, s15–s34 (2011).

      This article is a review of the manufacturing techniques available to produce microarchitectured materials.

      The conclusion of the review is that the technology is mature for the development, characterization, and optimal design of a novel class of multifunctional materials with the potential to achieve unprecedented combination of properties.

    1. S. R. Clark et al., Nat. Med. 13, 463–469 (2007).

      This paper details the process of how neutrophils, with the help of platelets, are able to trap bacteria in the blood and play an important role in controlling sepsis.

    2. J. J. Miner et al., Blood 112, 2035–2045 (2008).

      In this study, the deltaCD knock-in mice were prepared, whereas the cytoplamsic domain (CD) of PSGL-1 is removed.

    3. K. Szczur, Y. Zheng, M. D. Filippi, Blood 114, 4527–4537 (2009).

      In this paper, the authors show that neutrophils deficient in Cdc42 cannot maintain polarity (distinct leading edge and uropod).

    4. J. W. Semple, J. E. Italiano Jr., J. Freedman, Nat. Rev. Immunol. 11, 264–274 (2011).

      This is a review of the immune functions of platelets, the underdog cell type for most immunologists, This review highlights the essential roles platelets play in several immune functions.

    1. Introduction to Ecological Biochemistry

      An introductory textbook to the subject of "ecological biochemistry." This science is the study of the biochemistry of interactions between animals, plants and the environment, including the effect of plant toxins on animals.

    2. Revealing the paradox of drug reward in human evolution

      It is generally believe that drug abuse is the result of triggering reward systems in the brain. However, the most commonly used drugs are plant neurotoxins that evolved to deter herbivores from eating the plants, not reward them for it. How do we explain this contradiction?

      This paper outlines a few theories to explain this paradox, including the idea that humans may have evolved mechanisms to exploit these plant defenses.

    3. Effects of aging on acute toxicity of nicotine in rats.

      This and the publications listed immediately above and below it are meant to serve as evidence that while caffeine can be a stimulant and have positive effects, it is lethal when ingested at very high doses.

      This study showed that high doses of nicotine was lethal and caused convulsions in rats regardless of age. However, the older the rat was, the longer it took for the nicotine to be lethal. The older rats also had reduced neurobiological responses to the nicotine.

      The authors hypothesized that these effects reflected the older rats' reduced brain sensitivity to nicotine and decreased ability to metabolize nicotine in the liver.

    4. Pest control: Caffeine as a repellent for slugs and snails.

      This study published as a Nature Brief Communication showed that caffeine at high doses is lethal to slugs and snails.

      This and the two publications listed below it are meant to serve as evidence that while caffeine can be a stimulant and have positive effects, it is lethal when ingested at very high doses.

      This study has an important real-world application - as caffeine is a product that is already classified as "GRAS" (Generally Recognized as Safe) by the U.S. Food and Drug Administration, these results suggest caffeine has potential to be used as a safe alternative to some pesticides used on farm crops.

    5. Are we dependent upon coffee and caffeine? A review on human and animal data.

      This paper reviews available data on caffeine dependence, tolerance, reinforcement and withdrawal, including the effects of all of the above on humans and animals.

      It is referred to in this paper to support the idea that low doses of caffeine are mildly rewarding and enhance cognitive performance and memory retention.

    6. A case of fatal caffeine poisoning

      This and the two publications listed above it are meant to serve as evidence that while caffeine can be a stimulant and have positive effects, it is lethal when ingested at very high doses.

      This paper describes the case of a 21-year-old woman who ingested 10,000 mg of caffeine (and incredibly high dose). The woman went into cardiac arrest, and though she was resuscitated, she died in the hospital three days later.

    7. Tropical Agriculture: The value of bees to the coffee harvest.

      This paper counters the previously-held belief that the self-pollinating Coffea arabica plant did not benefit from insect pollinators. It shows that honeybees not only help with pollination, but also ultimately boost crop yields by over 50%.

    8. Economic value of tropical forest to coffee production

      This paper, as its title suggests, outlines an argument for the economic value of tropical forests to coffee production (and so argues against deforestation.) It is cited here to support the claim that plants of the genera Citrus and Coffea produce more fruits and seeds when pollinated by bees.

    9. Materials and methods are available in the supplementary materials in Science Online

      Found here

    10. M. E. Bitterman, R. Menzel, A. Fietz, S. Schafer

      This paper describes the experimental procedure behind the classical conditioning of proboscis extension in honeybees. It appears to be the first paper to do so, indicating its authors first established this protocol.

    11. Caffeine-induced synaptic potentiation in hippocampal CA2 neurons

      This paper shows that caffeine inhibits adenosine receptors and induces long-term potentiation of neurons in the hippocampus. This long-term potentiation of hippocampal neurons is critical for memory formation.

    12. Mushroom body memoir: From maps to models.

      This review discusses insect mushroom bodies. It is cited here as it discusses the evidence that mushroom bodies in insect brains participate in olfactory memory.

    13. Long-term synaptic plasticity in the honeybee.

      This paper describes the first demonstration of long-term synaptic plasticity in the honeybee brain. It is cited to show the long-term potentiation in insect neurons that is associated with memory formation.

    14. Selective impairment of learning and blockade of long-term potentiation by an N-methyl-D-aspartate receptor antagonist, AP5

      This paper showed that blocking long-term potentiation of hippocampal neurons interferes with learning and memory formation.

    15. Phytochemistry

      This paper found that there were significant amounts of caffeine in the pollen and nectar of citrus flowers. They further found that the presence of caffeine and other alkaloids was linked to the time during which the flowers were in full bloom (i.e., when a honeybee would be interested in them.)

    16. Evolution, discovery, and interpretations of arthropod mushroom bodies

      This paper is an overview of the history of research on mushroom bodies. Included in this overview is a discussion of the data showing that insect mushroom bodies are associated with olfactory learning.

    17. The role of extracellular adenosine in chemical neurotransmission in the hippocampus and basal ganglia: Pharmacological and clinical aspects

      This paper is cited here as it shows that caffeine can block A1 receptors (a presynaptic adenosine receptor in the brain).

    18. Associative and non-associative plasticity in kenyon cells of the honeybee mushroom body

      This paper showed that Kenyon Cells undergo associative plasticity after appetitive odor learning (as performed here with the conditioned scent.)

    19. Neural plasticity of mushroom body-extrinsic neurons in the honeybee brain

      This paper describes the first time that associative LTP was found in an interneuron of the insect nervous system (the authors stimulated honeybee Kenyon Cells and looked to see what happened.)

    20. Conditional modulation of spike-timing-dependent plasticity for olfactory learning

      This paper showed that spike-timing-dependent plasticity (STDP), which is responsible for adjustments in the strength of connections between neurons in the brain based on the relative timing of a particular neuron's output and input spikes, plays an important role in associative learning.

    21. Olfactory trace conditioning in Drosophila

      In order to look at the distinctions between the memory of an odor and a memory trace, the authors of this study established a protocol to look specifically at memories after trace conditioning.

    22. Mind the gap: Olfactory trace conditioning in honeybees.

      This study also describes the formation of memory traces that convey information about the initial odor that was used to stimulate the formation of the memory.

    23. Attraction, deterrance, or intoxication of bees (Apis mellifera) by plant allelochemicals.

      This paper tested the effects of certain defense chemicals produced by plants on honeybees. The alkaloids they tested, a group of chemicals that includes caffeine, were toxic and repellent to honeybees at relatively high concentrations.

    24. Consumption of an acute dose of caffeine reduces acquisition but not memory in the honey bee

      The study described in this reference is very similar to the one being performed here with one notable difference: the concentrations of caffeine being used were very high. The study's authors found that honeybees were repelled by very high concentrations of caffeine.

      Interestingly, such high concentrations did have have the same positive effect on the development of olfactory memory that low doses of caffeine had on the honeybees tested in this paper.

    25. Feeding responses of free-flying honeybees to secondary compounds mimicking floral nectars

      This study looked to see how honeybees reacted to compounds found naturally occurring in the nectar of some plants. The authors found that (with one exception) naturally occurring levels of these compounds did not have a repellent effect on the bees.

      However, concentrations of caffeine higher than those seen naturally occurring in floral nectar were repellent to the honeybees.

    26. Parallel reinforcement pathways for conditioned food aversions in the honeybee

      This study showed that honeybees can learn to detect toxins in nectar, remember that toxin and the negative effects it previously had, and in the future will avoid flowers whose nectar contains that toxin.

      This study did not use caffeine, but it proves the point that if caffeine was present in floral nectar at repellant concentrations, the bees would remember to avoid those flowers, which ultimately would have a negative effect on the plant's reproductive success.

    27. Caffeine: A well known but little mentioned compound in plant science

      This review sums up current knowledge of caffeine in the field of plant biology. It is cited here to back up the claim that caffeine has been found in the vegetative and seed tissues (as opposed to nectar and pollen) of plants in the genus Coffea at concentrations as high as 24 mg/mL. These values are quite high relative to the concentrations found in the nectar of these same plants.

    28. The evolution of floral scent: The influence of olfactory learning by insect pollinators on the honest signalling of floral rewards.

      This paper addresses the question of why flowers produce scent by looking at how olfactory learning of pollinators (like honeybees) influences how plants evolve to produce scents and chemicals in their nectar.

    29. Foraging dynamics of bumble bees: Correlates of movements within and between plant species.

      This study examines what conditions influenced foraging bumblebees' decisions to continue foraging from the same species of plant or move to a different species. They found a wide variety of conditions that affect honeybee foraging behavior, but one of the most important determinants was the amount of reward a bee received from a flower (i.e. nectar).

    30. Pollinator-mediated selection on flower color allele drives reinforcement.

      This paper looked at how pollinators, like honeybees, can drive the selection of flower color.

      In short, because honeybees prefer some colors to others, plants with flowers that are that color are more frequently visited by pollinators. Therefore, they are able to reproduce more and become more common.

    31. Sex and the Single Mustard - Population-Density and Pollinator Behavior Effects on Seed-Set.

      This paper showed that mustard plants with larger flowers (which in this case were more attractive to pollinators) had more pollen transferred to pollinators per visit than plants with smaller flowers.

    32. Cholinergic synaptic transmission in insect mushroom bodies in vitro.

      This paper is cited in the supplementary materials as the source of the protocol for making electrophysiological recordings from neurons located in a sensilla on the tip of the honeybee's proboscis.

    33. Distinct electrophysiological properties in subtypes of nonspiking olfactory local interneurons correlate with their cell type-specific Ca2+ current profiles

      This paper is cited in the supplementary materials as the source of the protocol for the bee's sensitivity to bitter compounds.

    34. Variation in complex olfactory stimuli and its influence on odour recognition.

      This paper is cited in the supplementary materials as the source of the protocol for part of their conditioning assay. As in this study, bees were trained by placing them in the conditioning arena and exposing it to a four-second pulse with an odor.

    35. Massed and spaced learning in honeybees: The role of CS, US, the intertrial interval, and the test interval.

      This study was cited in the supplementary materials as the source for the 30 second time interval used between trials during their conditioning experiments.

    1. T. Rudel , Is there a forest transition? Deforestation, reforestation and development. Rural Sociol. 63, 533–552 (1998).

      In reference 23, Thomas Rudel explains how forests change with economies. When an impoverished society's economy starts to grow, the society then cuts down many of the tree in it's surrounding territory.

      Once the economy grows to a certain point, however, the deforestation is replaced with reforestation, and the forest is replanted.

      At this point the forests may then be managed like a crop in cycles of planting and harvesting timber.

    2. S. Rodrigues, S. J. Andelman, M. I. Bakarr, L. Boitani, T. M. Brooks, R. M. Cowling, L. D. Fishpool, G. A. Da Fonseca, K. J. Gaston, M. Hoffmann, J. S. Long, P. A. Marquet, J. D. Pilgrim, R. L. Pressey, J. Schipper, W. Sechrest, S. N. Stuart, L. G. Underhill, R. W. Waller, M. E. Watts, X. Yan , Effectiveness of the global protected area network in representing species diversity. Nature 428, 640–643 (2004).

      In reference 22, Rodriguez and colleagues investigate land/nature reserves around the globe. When added together, 11.5% of Earth's surface is protected in nature reserves.

      They found that although a substantial portion of land is protected, the locations of these reserves do not necessarily cover areas with different types of ecosystems and different types of plant and animal species.

      Therefore, the present state of these land reserves is not optimized to protect as many species of plants and animals as possible.

      Yet, data like what Hansen and colleagues present in this paper could help improve how and where we select new nature reserves to protect more species.

    3. T. M. Brooks, R. A. Mittermeier, G. A. da Fonseca, J. Gerlach, M. Hoffmann, J. F. Lamoreux, C. G. Mittermeier, J. D. Pilgrim, A. S. Rodrigues , Global biodiversity conservation priorities. Science 313, 58–61 (2006).

      In reference 21, Brooks and colleagues review the different management strategies that are used to conserve plant and animal species (e.g., biodiversity).

    4. P. Potapov et al ., Mapping the world’s intact forest landscapes by remote sensing. Ecol. Soc. 13, 51 (2008).

      In reference 20, Potapov and colleagues published a world map that outlines the "Intact Forest Landscapes" (i.e., large areas of undisturbed forest). You can view the map here.

    5. S. S. Saatchi, N. L. Harris, S. Brown, M. Lefsky, E. T. Mitchard, W. Salas, B. R. Zutta, W. Buermann, S. L. Lewis, S. Hagen, S. Petrova, L. White, M. Silman, A. Morel , Benchmark map of forest carbon stocks in tropical regions across three continents. Proc. Natl. Acad. Sci. U.S.A. 108, 9899–9904 (2011). Baccini, S. J. Goetz, W. S. Walker, N. T. Laporte, M. Sun, D. Sulla-Menashe, J. Hackler, P. S. A. Beck, R. Dubayah, M. A. Friedl, S. Samanta, R. A. Houghton , Estimated carbon dioxide emissions from tropical deforestation improved by carbon-density maps. Nature Clim. Change 2, 182–185 (2012). N. L. Harris, S. Brown, S. C. Hagen, S. S. Saatchi, S. Petrova, W. Salas, M. C. Hansen, P. V. Potapov, A. Lotsch , Baseline map of carbon emissions from deforestation in tropical regions. Science 336, 1573–1576 (2012).

      In references 16–18, the authors describe baseline measurements for carbon emissions and stocks in tropical forests/regions.

      Now, what is the difference between a carbon stock and a carbon emission?

      A carbon stock is stored carbon. (Think of a tree trunk made of carbon-rich cellulose and lignin.)

      A carbon emission, however, is carbon that has been released into the atmosphere. (Now, consider a tree trunk that has been burnt to ash, thereby releasing carbon.)

    6. Prishchepov, D. Muller, M. Dubinin, M. Baumann, V. Radeloff , Determinants of agricultural land abandonment in post-Soviet European Russia. Land Use Policy 30, 873–884 (2013).

      Why were agricultural lands abandoned in Eurasian coniferous forests?

      The answer lies in changing political regimes. A large number of farms were abandoned in post-Soviet Russia (after socialism fell) because the economy and institutions of Russia where undergoing a radical change.

    7. J. A. Foley, R. Defries, G. P. Asner, C. Barford, G. Bonan, S. R. Carpenter, F. S. Chapin, M. T. Coe, G. C. Daily, H. K. Gibbs, J. H. Helkowski, T. Holloway, E. A. Howard, C. J. Kucharik, C. Monfreda, J. A. Patz, I. C. Prentice, N. Ramankutty, P. K. Snyder , Global consequences of land use. Science 309, 570–574 (2005).

      Hansen and colleagues reference work from Jonathan Foley and colleagues (2005), which details how harvesting natural resources can have negative effects through a decrease in ecosystem services.

      For example, Foley and colleagues show that "forests in the Yangtze watershed help moderate" water flow, which then supplies a hydroelectric plant with energy (40 million kilowatt hours per year). This energy is valued at $610,000!

      In comparison, this value is roughly 40% of the value of the trees in the forest that are then harvested for timber.

      In comparison, this value is roughly 40% of the value of the trees in the forest that are then harvested for timber. Thus, harvesting resources (in this case timber) can negatively effect other ecosystem services (in this case water flow), which are also important (e.g., worth $610,000 in energy).


      Which came first, the rain or the rainforest? Find out here and discover one of the many ways that forests affect our water supply.

    8. S. Goetz, R. Dubayah , Advances in remote sensing technology and implications for measuring and monitoring forest carbon stocks and change. Carbon Manage. 2, 231–244 (2011).

      In reference 40, Goetz and Dubayah summarize both aircraft and satellite imaging techniques. They also explain how tree canopy height is measured.

      Tree canopy height is measured by light reflectance. First, a laser on a satellite (in this case, NASA's Geoscience Laser Allometry System, or GLAS) is emitted and pointed at the surface of Earth.

      The light from the laser reflects off of Earth's surface and is then received by the satellite. The time that it takes for this to happen can determine the distance from the satellite to Earth's surface.

      When the laser is emitted over a forest, the tree's leaves and branches reflect the energy, yet some of the laser's energy will still reach the ground and will be reflected from the surface of the soil.

      Thus, the satellite receives two main light reflectance measurements: reflectance from the ground and reflectance from the tree canopy.

      Then, the difference in the time it takes for the ground reflectance and canopy reflectance light to reach the satellite determines how tall the trees are.

      For more information, check out Figure 2.

      For Hansen and colleagues' study, they decided that any plant that had a canopy height of 5 m or taller was a tree (rather than a shrub or herbaceous plant).

      Thus, determining canopy height is an important step in processing the satellite images to find where forests are distributed around the world.

    9. P. Gong, J. Wang, L. Yu, Y. Zhao, Y. Zhao, L. Liang, Z. Niu, X. Huang, H. Fu, S. Liu, C. Li, X. Li, W. Fu, C. Liu, Y. Xu, X. Wang, Q. Cheng, L. Hu, W. Yao, H. Zhang, P. Zhu, Z. Zhao, H. Zhang, Y. Zheng, L. Ji, Y. Zhang, H. Chen, A. Yan, J. Guo, L. Yu, L. Wang, X. Liu, T. Shi, M. Zhu, Y. Chen, G. Yang, P. Tang, B. Xu, C. Giri, N. Clinton, Z. Zhu, J. Chen, J. Chen , Finer resolution observation and monitoring of global land cover: First mapping results with Landsat TM and ETM+ data. Int. J. Remote Sens. 34, 2607–2654 (2013).

      In reference 36, Gong and colleagues describe the first study that uses Landsat satellite images that photograph Earth's surface at a 30 m by 30 m resolution.

      With these photos, they characterized Earth's surface into different land types (e.g., agricultural land, forests, grasslands, ice).

      They found that "forests, grasslands, and shrublands cover 28.35%, 13.37%, and 11.49% of the world, respectively. … Inland waterbodies, barren lands, and snow and ice cover 3.56%, 16.51%, and 12.81% of the world, respectively."

    10. M. Hansen, R. S. DeFries, J. R. G. Townshend, M. Carroll, C. Dimiceli, R. A. Sohlberg , Global percent tree cover at a spatial resolution of 500 meters: First results of the MODIS vegetation continuous fields algorithm. Earth Interact. 7, 1–15 (2003).

      In reference 30, Hansen and colleagues look at tree cover using the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument.

      The calculations for tree cover were then used in this current paper to determine forest distribution, loss, and gain.

      Also, note that technology is continuously advancing. Reference 30 was published in 2003. At this time MODIS was the most sophisticated satellite imaging instrument available. Yet, it could take images at a resolution of only 500 meters squared.

      In this paper from 2013, Hansen and colleagues use Landsat data that has a resolution of 30 meters squared.

    11. M. Hansen, A. Egorov, D. P. Roy, P. Potapov, J. Ju, S. Turubanova, I. Kommareddy, T. R. Loveland , Continuous fields of land cover for the conterminous United States using Landsat data: First results from the Web-Enabled Landsat Data (WELD) project. Remote Sens. Letters 2, 279–288 (2011).

      In reference 29, Hansen and colleagues detail the use of Landsat data to look at continent-scale images.

      This initial study helped Hansen and colleagues to then scale up to look at global patterns in land change in the present study.

    12. F. Achard, H. D. Eva, H. J. Stibig, P. Mayaux, J. Gallego, T. Richards, J. P. Malingreau , Determination of deforestation rates of the world’s humid tropical forests. Science 297, 999–1002 (2002).

      In reference 35, Achard and colleagues investigate deforestation in tropical humid forests. To do this, they surveyed 100 sites in Latin America, Africa, Southeast Asia, and India.

      Hansen and colleagues build off of this study by looking at all forests worldwide and do not limit themselves to particular sites.

    1. F. V. Mariani, G. R. Martin, Nature 423, 319 (2003).

      Discusses models of skeletal patterning.

    2. L. Niswander, Nat. Rev. Genet. 4, 133 (2003).

      Review of pattern formation in vertebrates, but more under the sense of development rather than regeneration.

    3. M. Carlson, Principles of Regenerative Biology (Elsevier Inc., London, 2007).

      A "textbook" that provides a basic foundation in regenerative biology. Discusses the dependence of skeletal muscle regeneration on nerves.

    4. G. Lemke, Sci. STKE 2006, pe11 (2006).

      Review article. Describes how Neuregulin-1 is the likely signaling molecule that causes myelin formation.

    5. J. P. Brockes, A. Kumar, Science 310, 1919 (2005).

      Review article. Discusses the field of limb regeneration in vertebrates and its possible contribution to medicine.

    1. M. Edwards, P. Scardina, L. S. McNeill, “Enhanced coagulation impacts on water treatment plant infrastructure” [American Water Works Association (AWWA) Research Foundation, Denver, CO, 2004].

      This is a book reference that includes information on experiments and case studies done to compare ferric chloride and aluminum use in water treatment and their effects on concrete corrosion.

    2. AWWA, Dawn of the Replacement Era: Reinvesting in Drinking Water Infrastructure (AWWA, Denver, CO, 2001).

      This reference can be visited in order to get an idea of approaching water infrastructure replacement requirements.

      They estimated that the budget requirement for the replacement of water infrastructures will be about $250 billion in the next 30 years.

    3. Volket al., Impact of enhanced and optimized coagulation on removal of organic matter and its biodegradable fraction in drinking water. Water Res. 34, 3247–3257 (2000).

      This reference investigates the use of an enhanced coagulation process in order to remove not only the particles, but also dissolved organic material in the water, which will help to increase the drinking water quality.