915 Matching Annotations
  1. Sep 2016
    1. discrete developmental units through reaction-diffusion

      Morphogens (chemicals which allow formation of traits), interact with each other to form specific concentrations at certain areas to form patterns and determine the placing of appendages.

      This is done by the chemicals activating and repressing the chemicals around them to varying degree leading to unique chemical gradients

    2. Several studies (9, 18–23) have shown that conserved signaling pathways, evidenced by the expression of the Sonic hedgehog (Shh), β-catenin (Ctnnb1), ectodysplasin A receptor (Edar), and/or bone morphogenetic protein (Bmp) genes, are involved in skin patterning and early morphogenesis of all amniote skin appendages

      The same signalling pathways were found in various different amniotes, suggesting it is a conserved across many species, and thus important.

      These include:

      Sonic Hedgehog (Shh)- factor in formation of organs and appendages.

      β-catenin (Ctnnb1) - Factor in gene expression and cell-cell adhesion.

      Ectodysplasin A receptor (Edar)- Factor in skin and nervous system development.

      Bone morphogenetic protein (Bmp)-Factor in skeletal formation.

    3. material cracking

      Due to exertion of force, the living material physically cracks the scale tissues. This leads to unique patterns on each crocodilian face.

    1. we employ a probabilistic algorithm developed by Kerr to determine applicant gender and ethnicity (Hispanic or Asian)

      The algorithm in question was developped by William Kerr to estimate the contribution of Chinese and Indian scientists to the US Patent and Trademark Office.

    1. Normal extinction training followed by poor retrieval of extinction is consistent with impaired infralimbic function

      In order to understand fear extinction, it is important to consider the underlying neural circuitry. Which regions of the brain are involved, and in what capacity? References 1 and 2 address these questions.

    2. One hallmark of extinction memory is its dependence on NMDA receptors

      NMDA receptors interact with glutamate and glycine in nerve cells. These receptors are found all over the central nervous system, and are involved in the processes of learning, synaptic plasticity, and memory formation.

      Fear extinction is an active learning process, and blockade of NMDA receptors (with the antagonist CPP) could interfere with fear extinction.

      See references 4, 8, and 9 for more information about the role of NMDA receptors in acquisition and extinction of fear memories.

    3. within the IL mPFC of the gene encoding BDNF correlates with fear extinction

      Extinction memories are long-lasting, and therefore require regulated gene expression. Epigenetic mechanisms are important to enduring changes in gene expression, so the authors examine the role of these mechanisms in fear extinction.

      In this study, Bredy et al. show that fear conditioning is accompanied by certain epigenetic changes such as an increase in H4 acetylation around the BDNF P4 promoter and an increase in prefrontal cortical mRNA expression of BDNF exons I and IV.

    4. Consolidation of extinction requires plasticity within the IL mPFC, which in turn depends on N-methyl-D-aspartate (NMDA) receptors, mitogen-activated protein kinase, and protein synthesis

      Decades of research have been devoted to understanding the neural mechanisms involved in fear conditioning. This work has led to a better understanding of extinction.

      In reference (2), the authors review new research on the neural mechanisms of the extinction learning process. They examine research describing the acquisition, consolidation, and retrieval of extinction memories, as well as the specific brain structures associated with these processes.

    5. IL single-unit responses correlate with the successful retrieval of such extinction memories (3), and IL stimulation strengthens these memories

      Extinction occurs when a conditioned stimulus (tone) is presented repeatedly without a footshock, and the conditioned fear responses to the tone diminish.

      Observations of spontaneous re-emergence of extinguished fear support the hypothesis that extinction does not erase the original fear memory, but instead forms a new memory that competes with the original memory and inhibits its expression.

      In this study, the authors show a relationship between infralimbic activity and extinction recall, which suggests that infralimbic neurons are involved in the process of recalling extinction memories.

    1. The ability to understand and actively respond to the affective state of a conspecific is crucial for an animal’s successful navigation in the social arena (4)

      From the review: Putting together phylogenetic and ontogenetic perspectives on empathy

      "The ability to perceive, share, and understand others’ affective states is crucial for successfully navigating the social world."

      "Broadly defined as empathy-related responding (Eisenberg and Eggum, 2009), this set of socioemotional competences underlies some of the most meaningful human interactions, from bonding between mother and child to complex prosocial behaviors (Batson, 2009), all essential for survival."

      [http://www.sciencedirect.com/science/article/pii/S187892931100048X]

    2. Rats may have acted to stop the alarm calls of the trapped rats (18)

      Altruism or Arousal in the rat?

      Previous work has shown that rats will press a bar to lower a fellow rat suspended in the air and showing signs of distress including squealing and wriggling (G.E. Rice and P. Gainer. J. Comp. Physiology and Psychol. 55, 123-125(1962).

      However, subsequent work showed that rats will press a bar to stop the sound of white noise more frequently than to stop the noise of a squealing rat.

      This suggests that any noise can elicit this bar pressing behavior. It also suggests that the motive behind the bar-pressing action of the rat is to stop the irritating noise and not to save its fellow rat.

    3. which is consistent with suggestions that females are more empathic than males (7, 12, 13)

      (7) Previous work has shown that female mice will frequently approach another familiar female mouse in pain, whereas male mice rarely approached another familiar male mouse in pain.

      (12) This study examined consolation through physical contact in chimpanzees and found "female chimpanzees offered more consolation to recent victims of aggression than males, suggesting that females were particularly responsive to the distress of others."

    4. Building on observations of emotional contagion in rodents

      In previous studies, rodents showed evidence of emotional contagion by demonstrating emotional behavior that is caught or shared from another individual.

      For example, emotional contagion for fear may lead one mouse to freeze upon seeing another mouse that is frozen in fear. In another example, rats react to a conspecific receiving a painful stimulus when they have experienced the same stimulus before.

    5. Sharing another’s distress

      In a human study, heart rate deceleration was an indicator of increased willingness to help someone in distress.

      However, if the person's heart rate accelerated when they saw someone in trouble, they were less likely to help the person, and more likely to try to remove themselves from the situation.

      Thus, identifying with someone's distress without yourself feeling in danger is a precedent for acting to alleviate that person's distress.

  2. Aug 2016
    1. Decision 16.83

      The Convention on International Trade in Endangered Species Decision 16.83 refers to the "Monitoring of illegal trade in ivory and other elephant specimens (Elephantidae spp.)."

      It states that any party involved in large scale ivory seizures (of 500 kg or more) has to collect samples from the ivory within 90 days of the seizure and, if possible, from all large seizures from the past 24 months. The samples are supposed to be handed in to the appropriate forensic analysis facilities that can reliably determine the origin of the ivory samples so that the crime can be immediately addressed.

    2. (9–12)

      An accumulating body of work published in references 9-12 set the stage and enabled the current study.

      For example, a study in 2001 revealed that African elephants that dwell in the forest are actually a different species than African elephants that live in the savanna. Until this study, these groups were lumped together as one species.

  3. Jul 2016
    1. Limb regeneration is abrogated if the blastema is denervated during the initial phase of cellular accumulation, but denervation after the mid-bud stage allows the formation of a regenerate

      From the information provided by Singer and Craven (1948), whatever role the nerves are playing with blastema, it is happening early in regeneration.

      When they remove the nerve later in regeneration there is no effect.

    2. independent of impulse traffic or transmitter release

      Sidman and Singer (1951) and Drachman and Singer (1971) demonstrated that neither activation of the neurons nor the release of neurotransmitters play a role in limb regeneration.

      There is likely something else about these nerves that give them their status in limb regeneration.

    1. that measles vaccination is associated with large reductions in all-cause childhood mortality but that there is no firm evidence to explain an immunological mechanism for the nonspecific vaccine benefits.

      Essentially, the who commissioned a group of expert scientists to take an objective look at all of the research that has been published in order to assess the evidence that there is truly a reduction in all-cause childhood mortality following measles vaccination.

      They found that there is in fact very strong evidence that all-cause mortality is reduced following vaccination.

      However, when they looked at all of the published studies they could not conclude that there is strong evidence as to why this happens because there are very few reports that successfully describe a mechanism for the reduced mortality.

    2. live vaccines may directly stimulate cross-reactive T cell responses

      Other researchers have attempted to explain the beneficial effect of measles vaccination by suggesting that the vaccination against measles may also protect from pathogens that have similar features as the measles virus.

      This type of protection, often conferred by T-cells, is called 'cross-reactive' because the same T-cells that might fight against the measles virus could also 'cross' over and fight against, or 'react' to an infection that is similar to measles. Hence the term cross-reactive T-cell response.

    3. profound, but generally assumed to be transient, immunosuppression that renders hosts more susceptible to other pathogens

      The articles referenced (14-17) are works by other basic researchers who have tried to better understand the cellular cause of this immunosuppression after measles infections.

      Researchers have identified types of cells and chemicals released by cells during measles infection that may help to explain this phenomenon.

    4. a loss of immune memory cells after MV infection resets previously acquired immunity, and vaccination prevents this effect

      Researchers used a measles virus that glows green and can infect monkeys to study where the virus goes in the body and what happens after infection that can explain what is going on. They observed that the virus infects and kills T- and B-cells, the important cell types required for the adaptive memory immune response.

      Destruction of these cell thus causes a loss of the memory that these T cells had regarding previous pathogens they had encountered, and it leaves the patient susceptible to infections that they were previously resistant to. This type of immune memory loss is termed immune-amnesia, similar to the type of memory loss that a person may have after getting hit very hard in the head, only immune-amnesia is due to loss of immune cells while amnesia after getting hit in the head might be due to the loss of some brain cells.

      Thus, it is possible that by vaccinating children against measles, the children would never get the measles infection and would therefore not lose their B- and T-cell memory, thus allowing them to remain resistant to all the pathogens against which they had spent the first years of their life building up immune memory.

    5. that they may train innate immunity to take on memory-like phenotypes

      Other researchers have attempted to explain the beneficial effect of measles vaccination by showing some evidence that vaccination may allow the innate immune system to take on some ability to remember particular pathogens, and thus be more effective at reducing other infectious diseases.

      Recall that innate immunity is the first line of defense. It is the generic immunity that is not usually assumed to have any memory and therefore doesn't usually totally cure one from an infection.

      In this case, there is some evidence that by vaccinating an individual, the individual's innate immune response may be 'trained' to be more like a memory or adaptive immune response. This could be beneficial because it means that the innate response, which is usually weak but has the advantage of being able to act against almost any infection, could actually, by taking on adaptive immune response type qualities, become stronger and cure from infections.

    1. (3)

      This previous study gave Gantz and Bier confidence in choosing the fly yellow locus as the target of their MCR experiment.

      The study by Port et al. demonstrated that this locus could efficiently be targeted by CRISPR/Cas9 and that mutations created by CRISPR/Cas9 could easily be detected by change in the color of the flies from brown to yellow.

  4. Jun 2016
    1. human AG2 protein was used as bait in a yeast two-hybrid assay and found to complex with a GPI-anchored protein called C4.4

      Human AG2 protein, which is similar to nAG, also likely binds to a GPI-anchored protein (C4.4).

      This is very similar to nAG, which binds to Prod1, a GPI-anchored protein.

    2. Blastemal growth is stimulated in experimental confrontations of cells differing in positional identity–for example in PD intercalation, in which a wrist level blastema is grafted onto a shoulder stump (31, 32)–and this is always dependent on the presence of the nerve

      When cells of different proximal and distal (PD) origin are grafted together on the salamander the blastema still grows. Though, the tissues may not become what is supposed to (i.e., it is not specified correctly).

      The experiment referenced had a distal wrist blastema grafted to a proximal shoulder stump. This results in formation of a normal limb regenerate, where the stump now forms the tissues between the shoulder and wrist, and the wrist blastema forms the hand

      However, if the limb is denervated this does not occur.

      The authors use this reference to suggest that nAG from the nerve is necessary for growth of the blastema even in situations where the PD gradient is abnormal.

    3. ligand for Prod 1

      Remember, the authors had previously found that Prod1 is a plasma membrane–bound protein.

    4. growth and division of these cells depends on the concomitant regeneration of peripheral axons

      Previous data from JP Brockes have shown that blastemal cells do, in fact, form in the denervated limb. However, the main observation from his paper is that these cells do not appear to grow or proliferate. There appears to be something special about the nerve that makes it necessary for the blastemal cells to function.

    5. distal cells of the larval axolotl blastema are converted to more proximal cells following focal electroporation of a plasmid expressing Prod 1

      Focal electroporation allows for introduction of exogenous DNA into a small region of tissue. To do this, a pulse of electricity is spread across the region of interest. This generates holes in the plasma membrane of the cells, which allows the DNA to enter into the cell.

      In this case Echeverri and Tanaka introduced a Prod1 overexpressing plasmid into distal cells of the larval axolotl blastema. Normally the cells here would not be expressing as much Prod1 as the proximal cells, but by electroporating in this plasmid these cells now start expressing a lot more Prod1 protein.

      The end result of this is cells becoming more proximal-like rather than becoming distal.

    6. salamander

      Salamander is a broad term for "lizard-bodied," amphibious animals. They include such animals as axolotls and newts and are sometimes referred to as urodeles.

      Of note is that salamanders have had a rich history of regeneration research. This is not surprising considering the amazing regenerative abilities of many species within this order.

      In fact, this field appears to be in a "renaissance." Because of the massive amount of new molecular and genetic techniques becoming available it is now possible to answer questions that were once unanswerable.

    1. Although most research on p53- and p21-regulated checkpoints has focused on the G1-S transition, several previous observations are consistent with an important role for these genes in G2-M (26–29)

      Previous work has clearly shown a role for p53 and p21 in the G1-S checkpoint, but there have been interesting results that suggested a potential role in the G2-M checkpoint.

      This paper was able to explain those results by investigating this G2-M role.

    2. The most likely biochemical explanation for the entry into mitosis in the absence of p21

      Previous research found that p21 triggers cell cycle arrest by inhibiting proteins called cyclins, which regulate progression through the cell cycle. Specifically, cyclin B1 and cdc2 form a complex that initiates entry into M phase (mitosis). p21 prevents mitotic entry by inhibiting this complex.

    3. Several potential mechanisms could account for these observations because p53 regulates the expression of many genes, including p21, that can affect the cell cycle (3–5, 17, 18)

      p53 is a transcription factor that can affect the expression of many target genes. Thus, when researchers look at cells lacking p53, it can be difficult to determine exactly what target genes are responsible for any observed defects.

    4. Cells with disrupted p21 or p53 that are arrested in G2 can undergo DNA synthesis, in some cases resulting in cells with DNA contents of 8n or higher (9, 10)

      In the G2 phase, cells have already duplicated their DNA, resulting in four sets of chromosomes (or 4n). If a 4n cell mistakenly undergoes another DNA replication before it divides, it will have a DNA content of 8n.

      This has been shown to occur in some cases when cells were missing p53 or p21.

    5. p53-regulated synthesis of the cell cycle inhibitor p21WAF1/CIP1 (3–5), which leads to inhibition of the cyclin-cdk complexes required for the transition from G1 to S phase

      A cyclin-CDK (cyclin-dependent kinase) complex is what drives a cell through different phases of the cell cycle.

      Previous work has shown that the p21 protein inhibits this complex at the G1 checkpoint, thereby preventing DNA replication in the S phase.

    6. This has stimulated much research to understand the cellular responses to DNA damage

      Scientists have been trying to understand how cells respond to and repair DNA damage because many cancer treatments work by causing DNA damage to cancer cells.

    1. The differentiation of most macrophage populations in adult mice is controlled by colony stimulating factor-1 (CSF-1) and its receptor (CSF-1R)

      It was shown that the expression of colony stimulating factor-1 ligand (CSF-1) and its receptor CSF-1R is a prerequisite for the differentiation of macrophages in the adult animal.

    2. in agreement with a previous report on 5-month-old parabionts

      Using parabiotic models, previous research showed that cells from the bone marrow and those that are circulating in the blood are not able to enter the brain in the absence of irradiation, which causes inflammation and disrupts the blood-brain barrier (BBB). In addition, intravenous injection of bone marrow cells in the circulation creates a pool of bone marrow cells that are not present in the blood under natural conditions, increasing their chances of reaching the brain.

      This indicated that previous findings reporting that monocytes enter the brain and differentiate into microglia in the adult brain could be attributed either to the loss of the BBB integrity in irradiated animals or increased numbers of bone marrow cells in the blood, or both.

    3. Although the mixing of the myeloid lineage is less efficient than the mixing of the lymphoid lineage

      Previous reports showed that in parabiotic mice recruitment of monocytes by the recipient mouse was more limited than the recruitment of B and T cells.

    4. evidence in favor of (6–8) and against

      Research of microglial turnover in adulthood used irradiation for bone marrow reconstitution and produced conflicting results: Some authors suggested that, similarly to the perinatal period, monocytes circulating in the blood can contribute to microglial turnover in the adult brain, whereas others found no influx of blood precursors into the brain in an adult animal.

    5. These results suggest that, in contrast to previous reports (4, 5), perinatal circulating hematopoietic precursors, including monocytes, do not substantially contribute to adult microglial homeostasis

      In contrast to this paper's and other recent findings, early research of microglial origin in the brain indicated that microglia arise from blood monocytes that migrate into the brain around the time of birth and continue influx throughout the adult life, replacing embryonic microglia and contributing to microglial pool in adulthood.

    1. because CBF is known to decrease with aging

      Compared to young adults, old adults had less regional cerebral blood flow associated with a delayed response. Therefore, a reduction in cerebral blood flow is associated with increased age in certain regions of the brain.

    2. These data are consistent with the previously reported negative effect of older blood on hippocampal neurogenesis (10

      The authors of reference 10 studied the decline of neurogenesis caused by blood-borne factors present in old mice.

      They created heterochronic parabiosis mice between young-old mice, and observed that systemic factors from old mice caused a decrease in synaptic plasticity of neurons, as well as a decline in spatial learning and memory skills in young mice.

    3. The hormone prolactin (3), dietary restriction (4), and an exercise/enriched environment (5) positively modulate neurogenesis, whereas increased levels of glucocorticoids associated with stress have the opposite effect (6).

      In reference 4, the authors recapitulate a mouse model of Alzheimer's disease and find that calorie restriction for 4 months could increase the expression of neurogenesis-related genes and decrease inflammatory-related genes in the hippocampus of these mice.

  5. May 2016
    1. in a recent report of high-strength microarchitected ceramic composites (34), their strength performance approaches the linear scaling relationship over a narrow density range, and only when loaded in a direction optimized for their anisotropic architecture

      Composite materials with the desired behavior have already been developed by another team.

      However, this behavior was only available under specific conditions and a narrow density range.

    2. An example of this is the Ni-P lattice reported by Schaedler et al. (20), whose specific stiffness (stiffness-to-weight ratio) degrades from 0.23 × 106 m2/s2 to 0.05 × 106 m2/s2 as density is reduced from 40 mg/cm3 to 14 mg/cm3 (45)

      The properties of a bend-dominated structure were shown to degrade significantly as the density is reduced.

    3. These differences in compressive behavior between solid and hollow-tube ceramic octet-truss lattices are primarily attributed to local buckling induced by the high aspect ratio of the strut length to nanoscale wall thickness, in contrast to nanoscale TiN trusses (32) and ceramic composite (34), whose aspect ratios are low enough to allow the nanoscale strengthening effect of the wall thickness to dominate

      The differences in compressive behavior between the different objects (hollow-tube compared with solid ceramic microlattices) observed by the authors of this study have been reported and explained previously by other teams.

    4. whose geometric configuration was proposed by Deshpande et al.

      The superiority of the stretch-dominated over the bend-dominated structure in regard to the mechanical efficiency has been suggested.

      Deshpande and his team have analyzed the criterion for the construction of a stretch-dominated structure (Maxwell's criterion). They have also investigated the mechanical properties of an octet-truss unit cell and shown its efficiency.

    5. Among these new designs are metallic microlattices with high recoverability when compressed (20, 26), TiN nanotrusses (32, 33), and ceramic composite trusses

      The common idea behind these new designs and processes proposed to build new materials with improved mechanical properties is that the material must present a structural hierarchy at different scales (micro, nano, etc.).

    6. A number of approaches in recent years have aimed to reduce this coupling between mechanical properties and mass density

      The problem of the dependence of the mechanical properties on the density has been addressed by different teams.

      They proposed various new designs and new fabrication processes, and they evaluated the relation between the relative density of the material and its mechanical properties.

      Even if an improvement was shown with these new processes, they can only be used to build materials in a small density range and often this improvement was only applicable in certain loading directions.

    7. A number of examples among recently reported low-density materials include graphene elastomers (19), metallic microlattices (20), carbon nanotube foams (21), and silica aerogels (22, 23).

      Because of the number of potential applications, several teams recently carried out research to propose new designs of lightweight materials.

      One inconvenience of these designs resides in the significant decrease of mechanical properties when the density is low.

    1. a process previously reported to be mediated by this integrin

      It has been shown before that without Mac-1 neutrophils are unable to crawl on the vasculature.

    1. Such learning typically does not challenge preexisting knowledge nor compete with daily experiences outside the laboratory

      Prior to this study, using sounds or smells to cue memories during sleep has been associated with memories for facts, events, and skills. These types of memories are not contradicted in participants' daily lives.

    2. In experiments that used a first-person-shooter videogame, both White and Black participants were more likely to shoot Black than White individuals, even when they held a harmless object rather than a gun

      In a first-person-shooter videogame participants were instructed to shoot individuals who held a gun and to refrain from shooting individuals who were holding non-gun objects such as wallets or soda cans.

      This finding remained even when experimenters increased the number of White individuals holding guns and decreased the number of Black individuals holding guns.

      The authors use this source to demonstrate that racial bias affects behavior (in this case the likelihood of incorrectly shooting an unarmed person).

    1. rats behave pro-socially when they perceive a conspecific experiencing nonpainful psychological restraint stress (14, 15),

      Both these reviews cite physical restraint of rats in cylindrical tubes as a source of stress.

    2. In contrast to previous work (5, 9, 16, 17)

      Previous studies have attempted to differentiate between altruistic and egoistic motivation driving helping behavior in rats.

      The studies concluded that the helping actions were driven by sensitization and conditioning, rather than empathy or altruism.

    1. toxic defense against herbivores

      See here to learn more about the types of chemical defenses produced by plants to protect themselves against herbivores: Plant Defenses Against Herbivory

    2. lethal in high doses

      It's estimated that the amount of caffeine necessary to be lethal is around 5 grams, or 40 gallons of coffee. Read here to learn more.

    1. all the dominant biological and photodegradation pathways of DOC

      This sentence points out a gap that the researchers who wrote this paper want to fill—there are no previous studies that measure both sunlight and microbe-driven breakdown of dissolved organic carbon and account for interactions between the two processes.

    2. constitutes only about 10% of bacterial respiration (i.e., biological mineralization) in inland or coastal waters

      In other words, before this study, scientists thought that sunlight played a smaller role than microbes in the break down of dissolved organic carbon to carbon dioxide.

    3. to CO2 (10, 11)

      Two of the authors of this paper were also involved in research showing that sunlight can stimulate carbon dioxide release from permafrost soil (reference 11).

    4. Carbon dioxide emissions from inland surface waters to the atmosphere are as large as the net carbon transfer from the atmosphere to Earth’s surface

      Previous research has measured how much carbon dioxide is released from streams, lakes, and rivers in the Arctic.

      George Kling, a professor at the University of Michigan, Ann Arbor, and an author of this paper, contributed to this research and is an author of two of the papers cited here.

    1. Nanofiltration

      Nanofiltration can be used in water and wastewater treatment to remove ions and organic substances. The applications can include water softening, color removal, industrial wastewater treatment, water reuse, and desalination. Additional information can be found in this peer reviewed article.

      Nanofiltration

    2. sulfate is reduced to hydrogen sulfide by sulfate-reducing bacteria

      Sulfate-reduction bacteria can use various electron donors including hydrogen, lactate, ethanol, and methanol.

      For more detailed information:

      A review of biological sulfate conversions in wastewater treatment (Review) Tian-wei Haoa, Peng-yu Xianga, Hamish R. Mackeya, Kun Chia, Hui Luc, Ho-kwong Chuia, Mark C.M. van Loosdrechtb, Guang-Hao Chena.

      Sulfur cycle:

      Sulfur Cycle

    3. polyaluminum chloride (PAC)

      Highly basic polyaluminum chloride (PAC) products can be used for water and wastewater treatment processes.

      See how PAC looks

      PAC is a type of aluminum product that is not as acidic as aluminum sulfate in the solutions. So during PAC addition, there is less risk of a shock acidic load in the treatment plants (Reference).

    4. Aluminum sulfate addition during drinking water production contributes substantially to the sulfate load in sewage and indirectly serves as the primary source of sulfide.

      Coagulation is a key process during drinking water purification. Aluminum sulfate is one of the most commonly used coagulants during drinking water treatment for removal of impurities such as suspended solids and natural organic matter.

      While aluminum forms precipitates, sulfate remains dissolved in the drinking water and ultimately ends up in sewage, and thus increases the total sulfate load in sewage.

    5. Ferric chloride

      FeCl3. This is a commonly used coagulant during water treatment, and also has wide-spread used during wastewater treatment for the removal of phosphate as well as sulfide.

      For structure image see

      Total chemical consumption is reported as 70% in wastewater treatment, 15% drinking water treatment, and 15% other (electronics, photography, and asphalt).

    1. The two experimentally evaluated interventions that do lower crime, at least during the program, involve such intensity and expense that their benefits fail to outweigh their costs (15, 16)

      One of the important findings of the empirical literature on youth and jobs programs is that job programs are very costly to operate. Often the social benefits of a program do not justify its costs.

    2. A similar SEL program has reduced violence on its own (45

      Previous research conducted by the author shows that social-emotional learning curriculum is capable of reducing violence even when a summer jobs program is not in place.

    1. Fire is the most significant cause of forest loss in boreal forests

      To discover more about boreal forest fires, click here.

      In addition, this refers to previous work from Potapov and colleagues (including some of the authors from this study.) that identified the cause of forest loss around the globe.

      They found that within the boreal climate domain "of the total forest cover loss identified, 58.9% is attributable to wildfires."

    1. such bumps only progress to form limbs if a piece of skin is grafted from the contralateral skin to the wound site so as to provide dermal fibroblasts of disparate identity

      When abnormal blastemas are formed via changing direction of the brachial nerve, fibroblasts from the dermis of the skin must be grafted to produce the full limb.

      Those fibroblasts are likely providing some sort of instructions telling the blastema how to form the rest of the limb as well as contributing directly to the new tissue.

    2. the deflection of the brachial nerve into a skin wound provided a growth stimulus to form an ectopic blastema or “bump”

      Artificially changing direction or "deflecting" the brachial nerve to another part of the salamander can cause an abnormal limb blastema to form.

      Remember, the brachial nerve is where they denervated the salamander at in many of their experiments.

      This suggests that something from the brachial nerve, likely nAG, is stimulating division and growth of these cells.

  6. Apr 2016
    1. Heterologous (“nonspecific”) and sex-differential effects of vaccines: Epidemiology, clinical trials, and emerging immunologic mechanisms.

      Ref 13. is a review from a conference where researchers met to better understand how factors about our lives can influence responses to vaccines. They propose that what vaccines we have received in the past, our childhood exposures, gender, and even our genes can affect our responses to vaccines.

    2. The observed benefits cannot be explained by the prevention of primary measles virus (MV) infections alone (11, 12), and they remain a central mystery (13).

      Ref 11. WHO and other researchers have found that the Measles vaccine, and other live vaccines, can have effects of childhood mortality not associated with the vaccine target. This reference is a review of some of the studies done in the past to try and better understand this off target effect.

      Ref 12. Scientists use a sample from Bangladesh to look at data similar to the results of this paper. They also find that Measles vaccinating reduces childhood mortality not due to Measles, specifically from diarrhea and oedema. However, the data used in their analysis is only one sample of a population and is confounded by some study control issues.

      Ref 13. Researchers have also noted that there are differences in the gender of the child that can change how protective the Measles vaccine is at protecting against other illnesses.

  7. Mar 2016
    1. (5)

      Gantz and Bier used the gRNA sequence targeting the fly yellow locus that was originally described by Bassett et al.

    2. (4)

      This previous study by Gratz et al. demonstrated that homology-directed insertion of large foreign DNA sequences could efficiently be inserted into the fly genome by CRISPR/Cas9.

    3. (4)

      Gantz and Bier used the Cas9 transgene described in Gratz et al. (vasa-Cas9) as the source of Cas9 in their MCR construct because this gene (vasa) is expressed in all cells of the fly.

    4. (1, 2)

      These two reviews by the Feng Zhang lab summarize much of the previous work done to lay the ground work of developing the CRISPR/Cas9 technology and its use in genome editing and making the mutagenic chain reaction performed in the current study possible.

    1. surface waters mediate C flux to the ocean and atmosphere that could represent up to 40% of the net land-atmosphere carbon exchange

      In other words, up to 40% of the carbon moving from the land to the atmosphere gets there via passing through surface water.

    2. the factors controlling oxidation of DOC in fresh waters are poorly understood

      It is currently unknown which processes are important for converting dissolved organic carbon from lakes, rivers, and streams into carbon dioxide.

    3. There is ample evidence that partial photo-oxidation can alter DOC quality and stimulate bacterial respiration (20–22), and in arctic rivers this photostimulated bacterial respiration can be a substantial portion of dark bacterial respiration of DOC (11).

      In other words, organic carbon is more available for microbes to eat and turn into carbon dioxide (bacterial respiration) after it has been partially broken down by sunlight. This process happens enough to be important when considering the total amount of bacterial respiration.

    4. Even in the deepest site measured, Toolik Lake (mean depth 7 m), areal photomineralization was more than half the dark bacterial respiration in the water column (Table 1) and was a similar or greater percentage than comparable measurements made outside the Arctic (14–17) or in coastal waters (18)

      Here, the authors validate their results by comparing them with previous studies.

      In Toolik Lake, they found at least as much sunlight-driven dissolved organic carbon (DOC) degradation (relative to microbial-driven DOC degradation) as has been previously measured in other locations.

    5. DOC in arctic surface waters is more labile to photodegradation relative to DOC in other fresh waters; this is consistent with prior evidence for high reactivity of arctic DOC to photodegradation (11, 22, 30, 31)

      Previous studies have found that because some of the dissolved organic carbon (DOC) in the Arctic comes from melting permafrost, it has little prior exposure to sunlight and can thus be degraded by sunlight more easily than DOC in other locations. The data in this paper are consistent with this previous research.

    1. But, there is an important difference between summer jobs for in-school youth and the previous literature: The well-studied youth employment programs generally act as tertiary prevention, targeting youth already out of school and struggling in the labor market

      Tertiary prevention refers to prevention that occurs after young people are already out of school. This study differs by focusing on young people as they are in school.

    1. Recently reported reductions in Brazilian rainforest clearing over the past decade (5) were confirmed,

      Hansen and colleagues are referring to previous work conducted by the Brazilian government, which looked at forest loss in the Amazon.

      This report from the Brazilian government shows that Brazil's forest protection laws are effective (i.e., the rate of forest loss in the Amazon is steadily declining).

    2. However, spatially and temporally detailed information on global-scale forest change does not exist; previous efforts have been either sample-based or employed coarse spatial resolution data (2–4).

      Hansen and colleagues are building off of previous scientific research that addressed this same issue of trying to figure out how forests are changing around the world.

      The main difference between this study and previous work is that technology has improved in such a way that we can now look at the entire globe at a very fine resolution to determine where and how our forests are changing through time.

    1. Several recent studies have found that greater political conservatism predicts higher levels of self-reported happiness and life satisfaction in the United States

      This means that previous research studies have found that an individual's happiness/life satisfaction can be statistically predicted, based on how conservative or liberal that person is; the more conservative people are, the happier they say they are.

    2. personality dimensions related to defensive forms of motivated social cognition

      In a meta-analysis, Jost, Glaser, Kruglanski, and Sulloway (2003) found that political conservatism was associated with a number of individual differences (such as openness to experience and fear of threat and loss) that relate to the motivation to manage uncertainty and threat.

    3. Self-enhancing tendencies are not evenly distributed across populations

      Heine, Kitayama, and Hamamura (2007) show support for the idea that people from Western/individualist cultures self-enhance significantly more than people from Eastern/collectivist cultures.

    4. Others portray conservatism as a protective or even defensive mechanism that serves the palliative function of justifying troubling societal inequalities

      This research, by Napier and Jost (2008), found that the happiness gap between conservatives and liberals could be explained by the fact that political conservatives are more likely than liberals to rationalize inequality.

      In one study, the researchers looked at U.S. economic inequality over time (from 1974 to 2004), and found that, in general, more inequality was associated with lower well-being, but that conservatives seemed to be somewhat buffered from this effect. As inequality goes up, well-being goes down a lot for liberals, but only a little for conservatives.

      Other research (for example, Jost and Hunyady, 2002) also shows that conservatives are generally more likely to view the status quo (or, the way things are now) as being fair.

      So, the implication is that conservatives seem to be less bothered by inequality.

    5. systematic methodological artifacts due to common method variance

      The argument here is that if research relies too much on just one way of doing things (in this case, using self-report), then this single methodology might be overlooking an important issue.

    6. many challenges involved in self-report research

      For example, Zou and Schimmack (2013) argue that self-report measures should look at multiple raters; that is, in addition to asking participants about themselves, researchers should also validate those ratings by asking the same questions to people (family, friends) who know the participant well.

    7. Non-Duchenne smiling is also less predictive than Duchenne smiling of beneficial long-term psychological and physical health outcomes

      For example, research by Harker and Keltner (2001) showed that, compared with non-Duchenne smiles, displays of Duchenne smiling in yearbook photographs were associated with higher levels of personal well-being at ages 21, 27, 43, and 52.

  8. Nov 2015
    1. benefits of this counterbias training can be fragile, subject to reversal when the original stereotypes are again reinforced in typical circumstances, such as through the media

      In this study researchers extracted short clips from 11 popular television shows, muted the clip so no sound was produced, erased the character that was being interacted with, and asked participants to rate how the other characters were interacting with the 'invisible' character. Results showed that invisible White characters were interacted with more positively than invisible Black characters.

      These same clips were shown to another group of participants and the results showed that exposure to more racially biased nonverbal clips resulted in more implicit bias.

      The authors use this study to demonstrate that nonverbal bias cues are prevalent in our environment and can impact participants' implicit bias suggesting that our environment can counteract any training that we might do.

    2. out-group members can be perceived as threatening, and the fear response to those individuals can resist extinction

      In this study researchers presented participants with two Black faces and two White faces. One of the Black faces and one of the White faces was paired wit a mild electric shock (painful but not hurtful) such that each time the participants saw one of the two shock-associated faces they received a shock.

      The researchers then continued to present the faces but stopped giving the shock and measured the fear response.

      The results showed that participants established a fear response to both Black and White shock-associated faces but the fear of the Black shock-associated face persisted while participants stopped fearing the White shock-associated face sooner. When this study was conducted with Black and White participants, for White participants the Black face continued to show a fear response, for Black participants the White face continued to show a fear response.

      The authors use this study to demonstrate that fear of out-group members (members of a group that's not your own) may have a tendency to result in a biological fear reaction that may be particularly difficult to extinguish.

    3. implicit biases can be reduced by learning about counterstereotype cases

      This study compares two types of counterbias training. In one training. In the first type, participants were supposed to respond "YES" when they saw a counter-stereotype pair (e.g. male and weak or female and strong). In the other type of training participants were supposed to respond "NO" when they saw a stereotypical pair (e.g. male and strong or female and weak).

      The results showed that counter-stereotype training (saying yes to counter-stereotypes) DECREASED implicit bias while stereotype negation training (saying no to stereotypical pairs) INCREASED implicit bias.

      The authors use this study to justify the use of counter-stereotype training in this experiment and the show that previous studies have found it effective.

    4. perceived social norms can prescribe people’s expression of stereotyping and prejudice

      In this study, participants rated how appropriate it would be to express prejudice to over 100 different groups (e.g. Black Americans and White Southerners but also liars, child molesters, drunk drivers, and doctors). Then a separate group of participants were asked to rate their personal feelings toward each of the 100 groups.

      The researchers found that willingness to express personal prejudice against a group was strongly related with how acceptable it was to express prejudice against that group.

      The authors use this source to demonstrate that society tells you you're allowed to say about a person influences what you do say about them.

    5. For instance, implicit racial biases decrease investments given to racial out-group members in a trust game

      In the trust game, participants were presented with a picture of a face and they had to decide whether to offer the person $10 or not. If the participant gave the person $10, the person received $40 and could either give the participant half (so they each received $20) or could keep it all for themselves. Participants saw 300 faces (100 White, 100 Black, and 100 other race) and made the decision to give $10 or not for each face.

      Researchers found that the amount of implicit bias participants had was correlated with how much more likely they were to offer a White person money than a Black person. This was not related to participants' explicit report of racist attitudes.

      The authors use this source to support their assertion that implicit attitudes of race are correlated with behavior.

  9. Oct 2015
    1. PAM sequence NGG

      This is crucial to the bacteria or archaea distinguishing between self and not self.

    2. clustered regularly interspaced short palindromic repeats

      CRISPR systems provide bacteria and archaea with acquired immunity and may also play a role in regulation of DNA expression. For a review of CRISPRs, see this link:https://dpb.carnegiescience.edu/sites/dpb.carnegiescience.edu/files/Bhaya_ARG.pdf

    3. bacterial type II CRISPR system

      The bacterial type II CRISPR system is the best known system and also the least complex system.

    4. reconstitution of the Streptococcus pyogenes type II CRISPR system demonstrated that crRNA fused to a normally trans-encoded tracrRNA is sufficient to direct Cas9 protein to sequence-specifically cleave target DNA sequences matching the crRNA

      The cited article describes an experiment which demonstrated DNA cleavage by Cas9, principal protein in type II CRISPR systems. Cas9 protein was purified from a preparation of Streptococcus pyogenes.

      The researchers found that addition of crRNA alone was not able to guide cleavage of target plasmid DNA, but with the addition of tracrRNA the cleavage occurred.

      By comparing these results with similar results using short double sequence DNA, the authors demonstrated that the functions of tracrRNA are triggering the enzyme RNase III and activating cleavage of target DNA by means of cas9 under the guidance of crRNA.

      The authors fused the two essential elements: crRNA and tracrRNA to provide greater convenience for targeted genetic editing.

      Jinek, M., Chylinski, K., Fonfara, I., Hauer, M., Doudna, J. A., & Charpentier, E. (2012). A Programmable Dual-RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity. Science (Washington D C), 337(6096), 816-821.

    5. AAVS1 locus

      The AAVS1 locus is a target on human chromosome 19 that is frequently used for testing purposes. The reason for this is that there have been no known adverse effects from genetic manipulation in this area http://www.genecopoeia.com/product/aavs1-safe-harbor/

    6. clustered regularly interspaced short palindromic repeats

      The scientists who first discovered these sequences had no understanding of their possible function. Later it was observed that some of the spacers correspond to the DNA of invading viruses.

      This led to the discovery that CRISPRs play a protective role defending bacteria and archaea from other invasive organisms.

      There is speculation that this immune function is only one of the functions of CRISPRs. They may be involved in other functions such as regulating the genetic expression of the barcterial or archaeal organism's own DNA. https://www.quantamagazine.org/20150206-crispr-dna-editor-bacteria/

    7. CRISPR-associated (Cas) systems

      CRISPRs do not act in isolation. They are part of a complete system which includes the CRISPR array, associated genes, and an upstream leader sequence. The CRISPR array is the strand of DNA with repeating and unique segments interspersed.

      Many, but not all, of the repeating segments are palindromes (sequences that read the same from right to left as the do from left to right). Many of the spacers have DNA which matches that of invading viruses (phages) or plasmids. CRISPR associated genes often code for proteins which can cleave or bind DNA or RNA sequences. The leader sequence of the system occurs before the first repeat and is important for transcription as well as for obtaining new spacers. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3497052/

    8. adaptive immune defenses

      Adaptive immunity is immunity that one gets in response to challenges from the environment. This is in contrast to innate immunity, which is the immunity one is born with.

      Adaptive immunity is not something exclusive to higher animals. Bacteria and archaea also have immune responses to foreign organisms which threaten them (mainly viruses and plasmids) http://www.ncbi.nlm.nih.gov/pubmed/23495939

    1. At a broader level, the gender gap in science achievement in a nation is correlated with the level of implicit stereotyping of females as not having an aptitude for science

      In this study more than 500,000 participants completed the gender and academics Implicit Association Test (a test that measures your unconscious associations between different genders (males and females) and different academic areas (liberal arts and sciences).

      The researchers found that countries where participants had higher

      Nations with higher implicit bias scores (associating males with science and females with liberal arts) had larger differences between males' scores and females' scores on an international standardized 8th grade science test.

      The authors use this source to support their claim that unconscious gender biases are associated with real-world outcomes.

    2. When hiring potential research assistants, both male and female faculty members were more likely to hire male than equally qualified female candidates

      Over 100 science faculty in research universities across the US were asked to determine a starting salary for and rate the application materials of potential research assistants. There were two versions of each application that were identical except that one had a female name and one had a male name. Each faculty member received one of the two versions for each application.

      Faculty members rated the male applications higher and suggested a higher starting salary than the identical female applications.

      The authors use this source to demonstrate that gender bias affects behavior (in this case the likelihood of hiring a research assistant based on an application).