Corals compete for space and light with each other as well as other organisms such as algae. Algae has the ability to grow much faster than coral and can quickly overgrow and shade coral if given the chance. Reef herbivores such as the sea urchin Diadema antillarum play an important role in keeping algae at bay, maintaining coral reefs.

Corals sexually reproduce by releasing large numbers of eggs and sperm into the water at once. This requires synchronized timing between multiple colonies and may only happen once a year.

Corals can also form colonies by asexual reproduction—coral fragments that break off of a parent colony can survive and grow into a new colony. New colonies are also sometimes formed by budding off of existing colonies.

Various studies describe the aftermath of tropical cyclones on coral reefs. Effects of storms seem to vary depending on the structure, form and composition of the affected reef.

None of the studies cited had intimate knowledge of the impacted reefs immediately before the disturbance.

Making robust ecological conclusions about the effects of a natural event, such as a hurricane, on an ecosystem requires thorough knowledge of that ecosystem both before and after the event.

Because Jamaican coral reefs were well-studied before, during, and after Hurricane Allen, this study is unique from previous studies of the effects of hurricanes on coral reef organisms.

Hurricanes hit the southern coast of Jamaica more often than the northern coast, and scientists have previously thought that this may be the reason for the observed differences in coral communities.

Differences include larger areas of dead coral and lower population densities of corals in certain reef zones on the southern coast.

Disturbances in the environment, such as storms and fires, can affect the state of an ecological community.

For example, traditional ecological knowledge dictates that when disturbance is very frequent or intense, all species in the affected area may become locally extinct—but when disturbance is very rare, the community may become dominated by only the most competitive species. An intermediate level of disturbance may, counterintuitively, maintain the highest level of biodiversity.

Prinz and colleagues comment on their experience as employees of a pharmaceutical company, which relies on preclinical research to decide whether to invest into the exploration and development of new drugs. Because companies find many preclinical research findings unreliable, they now often conduct their own research to reproduce the original findings before they decide to move on and invest large sums of money into the actual drug development. Only in about 20% to 25% of the cases did the company scientists report finding results of the reproduction that were in line with the originally reported findings.

Begley and Ellis are cancer researchers, who propose ways for research methods, publication practices and incentives for researchers to change so that research would yield more reliable results, such as more effective drugs and treatments. They argue that often new drugs and treatments enter clinical trials, which test their effectiveness to treat cancer in humans, before they reach sufficient standards in preclinical testing, leading to non-reproducible findings. To achieve more reliable preclinical results, they argue that more focus should be placed on reproducing promising findings in the preclinical phase.

Schmidt argues that, although replication is critical for scientific progress, little systematic thought had been applied to how to go about replications.

He suggests to differentiate direct replication (the repetition of an experimental procedure) and conceptual replication (the repeated test of a hypothesis or result using different methods).

Moreover, he summarizes five main functions that replications serve: to control for sampling error, artifacts or fraud, to extend results to a larger or different populations and to check the assumptions earlier experiments made.

Schmidt concludes that, although a scientific necessity, replications can be practically difficult to conduct, in particular because this type of work is not always easy to publish or highly regarded. Instead, he recommends that studies which include novel research questions could also include elements of replication of previous findings.

Ioannidis conducted simulations to show that for most studies, it is more likely for a finding to be a false positive than true identification of an effect. Among the factors that make it more likely for research findings to be false are a small size of the sample or the underlying effect, and when designs, definitions and analyses are more flexible rather than rigorously objective.

In this editorial, Prahler and Wagenmakers argue that doubts about the reproducibility of findings in psychology became increasingly critical after events such as the fraud case of Stapel in 2011, where fabricated and manipulated data resulted in numerous retractions of journal articles, or the debate around findings published by Bem in 2011, where claims that people had an ability to forsee the future were shown not to be replicable. The suspicion that researchers engaged in "questionable research practices"(QRPs) turned out to be more justified than the field had hoped for, for instance based on Simonsohn's findings that many psychologists admitted to engaging in some of these QRPs.

Many Labs replication projects are studies in which multiple labs attempt to replicate the same effect. In this example, 36 teams of researchers from different countries attempted to replicate the same 13 effects, with more than 6000 participants.

The data revealed that 10 effects could consistently be replicated, while one effect showed only weak support for replication and two effects could not be replicated successfully.

Nosek and colleagues summarize eight standards for transparency and openness in research that focus on citations, data accessibility, accessibility of computational resources, making research materials like participant instructions available and giving access to the design and analyses, study and analysis plan pre-registration, and the use of replication studies over all. They argue that journals should require and enforce adherence to transparency guidelines, and that the submission of replication studies, in particular in the Registered Report format, should be an option.

These articles provide an overview of arguments calling for reproducibility from the perspective of philosophy of science, arguing that scientific theory and explanation require reproducibility to enable scientific progress.

The Open Science Collaboration published its plan for the Reproducibility Project. They announced how they would select the studies to be replicated, basic principles for how the replications would be conducted and how the results would be evaluated, and invited researchers to join the team conducting the replications.

Nosek and Lakens argue in this editorial that registered reports are a partial solution to the problem of few incentives for researchers to conduct replications. A registered report is an article format, where a proposal for replication is peer-reviewed before data is collected, and the pre-registered report of the replication will be published no matter what the data shows.

In Tang’s article, ZIKV infection led to a significantly higher caspase-3 activation in human NPCs.

ZIKV infection of hNPCs resulted in reduced growth, which led Tang to suggest that it might be due to both increased cell death and an interrupted cell-cycle.

Using in situ hybridization (labeling nucleic acids with probes) on sections of dengue-2 infected mosquito cells, Grief showed that in dengue-2 infected mosquito cells, the smooth membrane structures contained both viral RNA and virus particles.

This suggests that the smooth membrane structures are important sites for the concentration of viral RNA and possibly for formation of the viral envelope.

Tang et al. obtained human neural progenitor cells (hNPCs) from stem cells. They used a particular ZIKV strain that successfully infected hNPCs, and found that the infected cells released ZIKV particles.

The growth of hNPCs was stunted, and an analysis of DNA content suggested that this attenuation might have been due to a disturbance in the cell cycle.

In several case studies of pregnant women diagnosed with fetal microcephaly, the women suffered from symptoms of infection with Zika virus.

After miscarrying, ZIKAV RNA and antigens were detected in the placental tissues and the amniotic fluid of the microcephalic fetuses. The sequencing analysis of the virus genotype revealed a genotype of Asian origin.

Read more case studies that made headlines:

http://www.dailymail.co.uk/health/article-3451984/Zika-cross-placenta-infect-unborn-babies-Traces-virus-amniotic-fluid-surrounding-two-fetuses-diagnosed-microcephaly.html

Zika virus has also been detected in microcephalic fetuses.

The Brazilian strain of the virus has been traced to an Asian strain.

The cerebral cortex (the outer layer of the brain) shows the most severe reduction in microcephaly. This might be explained by reduced division in the cells that neurons come from, resulting in fewer neurons. This, in turn, leads to a smaller cerebral cortex.

These articles show that receiving a grant for postdoctoral research leads to an increase in productivity.

In these articles, the authors found out that there was no link between higher ratings from the peer-review committee and the number of citations the article eventually got.

In this article, the authors showed that getting a research grant depends partially on chance. They reviewed the same proposals with different committees, who each gave different results.

The aim of the peer-review committees is to both ensure the quality of research and encourage innovation. However, it has been shown that peer review committees can be undermined by various factors.

It might be difficult to recreate this mouse model in humans because previous research has shown that removing the gene that encodes tau in humans leads to serious learning impairments.

During the course of Alzheimer’s disease, excess stimulation can occur in neurons, causing problems in the brain (including seizures).

http://www.medscape.com/viewarticle/813029

Previous research has shown that fragments of abnormal tau are toxic and may also play a role in how toxic amyloid-β is to neurons. In fact, neurons lacking tau seem immune to damage by amyloid-β.

This may be the reason why, in this study, the researchers found that the reduction of tau had improved memory, even though amyloid-β or plaque levels remained unchanged.

http://www.ncbi.nlm.nih.gov/pubmed/15930385

Phosphorylation adds a phosphate group to a molecule. When proteins (like enzymes) are phophorylated, their function and activity changes.

Abnormal tau that is more phosphorylated than normal is a hallmark of Alzheimer’s disease.

In mice, tau is phosphorylated similarly to tau in humans, which makes comparisons feasible and simple.

Previous research has shown that damaging an area of the brain (the entorhinal cortex) that sits next to the hippocampus can make an animal hyperactive.

Damage to the entorhinal cortex is common in Alzheimer’s disease. Using the same methodology as in previous studies, the authors therefore tested their mice for increased hyperactivity to see whether there was any evidence of damage to this brain area.

Although the sequence of molecular events that causes Alzheimer's disease was and still is unclear, it is generally believed that, as a first step, amyloid-β proteins build up into plaques; then, abnormal tau proteins kill neurons and build up into tangles.

Targeting plaques as a treatment therefore made sense, because, if successful, it would affect the disease earlier in the process of neural destruction.

When this paper was published in 2007, virtually all experimental treatments for Alzheimer’s disease targeted the amyloid-β proteins, either to stop their production, to help the brain get rid of them better, or to stop them from building up into plaques.

The plaques formed from built-up amyloid-β were easy to see in tissue samples from Alzheimer’s patients and it seemed like an obvious target.

Electric organs after millions of years of evolution have become a highly useful tools that are used by animals in many ways, such as communication, navigation, predation, or defense. Despite millions of years of evolution and many physical differences between the electrical cells of electrogenic species, it is seems that they all share the same origins and demonstrate the same cellular pathway and similar transcription factor.

Electric eels are found in muddy bottoms of still fresh waters in the South America, specifically the fresh waters of the Amazon and Orinoco River basins. They are found in swamps, creeks, and small rivers, and coastal plains. They feed on invertebrates, and adults consume small fish and mammals.

Prior researches study the optimal pulse sequence on the muscle that lets maximize the muscle contraction. This work is interesting because it is a report of the normal condition optimum for a muscular activation from the electrical pulse of the neuronal system. This allows the author of this paper to state that the eel's electrical pulse are optimal for the generation of an muscular tension.

Muscles are led by motor neurons, to better answer to the body demands, motor units emit three sorts of neuron's impulsion that modulate the muscular contraction and the motor system used.

Look at the annotation of the first reference. There you can find more information about this work

Eels are not the only ones to be studied for their ability to produce electricity to survive. Indeed, other astonishing animalas use this system, like Stargazers or Rays called "Torpedo".

When the order of generating electricity is given by the brain, the electrical cells of the Eels organ are activated. An entry of ions in the wall of each cell is created, this action changes the polarity of the entire cell. This works like a battery of a car that generates an electric current due to ion differences in the electrodes. This potential in addition of all the other cells generate a big potential up to 600volts !

Scales that cover the feet of birds have been shown to be different to other scales, with different molecules and development patterns, so it could be independently developed.

The scales on the feet pads of birds (e.g. chickens) show very similar pathways to the ones in reptiles, far into the development of the embryo.

In contrast, this similarity is not as easily observable in feather or foot covering scales compared to reptile scale development, leading to works hypothesising that they are not related.

The development of feathers develop in 10 different areas and these areas correspond to different parts of the body.

These tracts develop at different rates and have their own patterning.

The two models proposed by various papers over time both propose that the evolution of the placode occurred independently twice.

This means that the signalling molecules were evolved independently in different organisms but ended up with similar functions.

Scales form with risen areas in the dermo-epidermal layer (the skin) which then further develop into scales which are different depending on the species and where it is on the body.

Previous work suggests that although there are similar molecules found in the development of feathers, hair and scales, they all function differently and evolved independently.

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

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.

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

In this research, the authors examined three affected males in the same family, all of whom exhibited characteristics as profound developmental delay, ataxia, hyperkinetic behaviour etc, which were suspects for Angelman syndrome, but relevant genetic examinations regarding this diagnosis had been negative.

They performed linkage analysis and DNA sequencing and they identified a deletion in the SLC9A6 gene encoding the Na+/H+ exchanger NHE6. Mutations in SLC9A6 cause X-linked mental retardation.

In this research, the authors worked on the description of the phenotype, genetic mapping, and identification of the defective gene in the swe mutant mouse.

This spontaneous mouse mutant, s low-w ave e pilepsy, (swe), is related to neurological syndrome, including ataxia, as well as a unique epilepsy phenotype consisting of 3/sec absence and tonic-clonic seizures.

It found to be located on chromosome 4 and identified as a null allele of NheI, which is ubiquitous, mediates the electroneutral 1:1 of Na+ and H+ and takes part in the regulation of the pH, cell volume and response to growth factors.

Swe mice were the first to model essential elements of human generalized absence epilepsy seizures and since it is characterised as null allele of Nhe1, it is the first disease-causing mutation identified in an Nhe gene.

The authors of this article compared their results with various studies of de novo CNVs and showed that the results obtained in this study are similar to the previous results obtained by Sebat and colleagues. Sebat and colleagues studied specifically proved that de novo CNVs detecting can be an interesting approach to detecting new genes linked with autism.

In this article, a significant number of transcriptional regulators, which mediate activity-dependent gene transcription were identified.

This is interesting given the significant advances in understanding how the calcium-dependent activation of signalling cascades by extracellular stimuli takes part in the regulation of transcription-factor function.

In this study, only two families presented overlapping loci. The region was identified in the study conducted by the International Molecular Genetic Study of Autism Consortium as a region where the highest LOD score was observed.

The research team led by De Silva studied the genetic factors associated with ADHD. One of the identified genes was SLC9A9 and they discovered that this gene codes for a sodium/hydrogen ion exchanger that is expressed in the brain, but also in the heart and the skeletal muscles.

Hoodfar and Teebi studied the link between inbreeding and the prevalence of different genomic abnormalities. In this study, the amount of autosomal recessive disorders was more than doubled in consanguineous families.

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.

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.

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.

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.

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.

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.

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]

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.

(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."

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Professor Wilson has been a pioneering researcher on issues of poverty. His website shows examples of his past research.

https://www.hks.harvard.edu/about/faculty-staff-directory/william-julius-wilson

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.).

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.

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.

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

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.

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).

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

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.

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

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.

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.

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.

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).

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.

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.

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:

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

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).

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.

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.

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

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.

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.

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."

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.

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.

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.

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.

For more information on how neutrophils migrate, see:

http://www.urmc.rochester.edu/labs/Kim-Lab/projects/mac-1_cd11bcd18_in_neutrophil_migration

https://www.youtube.com/watch?v=_gSsVrrUtrw

This would be a good place for a previous work annotation

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

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.

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.

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.

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

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

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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

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.

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/

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/

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/

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

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.

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).

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