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<jats:title>Looking for the Dark</jats:title> <jats:p> Mature <jats:italic>Drosophila</jats:italic> larvae wander away from food and seek a dark site for pupation. While investigating this phenomenon <jats:bold> Yamanaka <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6150" page="1113" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241210">1113</jats:related-article> ) found that four prothoracicotropic hormone (PTTH)–producing neurons mediate light preference in the central brain. PTTH circulates in the hemolymph and signals via its receptor, Torso, to two light sensors, sensitizing them for light detection. The larvae can then transform from wandering larvae into immobile pupae hidden from light and predatory eyes. </jats:p>

<jats:title>smORFing for Calcium</jats:title> <jats:p> Genomes contain thousands of small open reading frames (smORFs), short DNA sequences coding for peptides of less than 100 amino acids. <jats:bold> Magny <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6150" page="1116" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238802">1116</jats:related-article> , published on 22 August) describe two smORF-encoded peptides of less than 30 amino acids regulating calcium transport and, hence, regular heart contraction, in the fruit fly <jats:italic>Drosophila</jats:italic> . These peptides seem to have been conserved for more than 550 million years in a range of species from flies to humans, where they have been implicated in severe heart diseases. Such conservation suggests that smORFs might be an ancient part of our functional genome. </jats:p>

<jats:title>Deafness and Misbehavior</jats:title> <jats:p> Behavioral problems accompanied by hyperactivity often occur in children with severe hearing loss and vestibular impairment. Explanations have focused on socioenvironmental factors, but <jats:bold> Antoine <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6150" page="1120" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240405">1120</jats:related-article> ) found that inner ear defects can cause dysfunction in the striatum, which leads to abnormal behavior—especially hyperactivity—mediated by dopamine and glutamate signals, in an area of the striatum that is instrumental in controlling motor output. The abnormal behavior can be reversed by injection of an extracellular signal-regulated kinase inhibitor, which provides a novel target pathway for the treatment of behavioral disorders. </jats:p>

<jats:title>Number Sense</jats:title> <jats:p> Numerosity perception resembles primary sensory perception and, indeed, it has been called the number sense. As all primary senses are organized topographically in the cortex, <jats:bold> Harvey <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6150" page="1123" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239052">1123</jats:related-article> ) tested the hypothesis that numerosity is also organized topographically. Applying ultrahighfield functional brain scanning and using custom-designed analysis, they confirmed that a topographical numerosity map occurs in the human parietal cortex, which displays conventional characteristics, such as a systematic relationship between the cortical location's preferred numerosity and cortical magnification and tuning width. </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>

<jats:p>Listen to stories on failed stars, numerosity in the brain, monitoring a North Korean volcano, and more.</jats:p>

<jats:sec> <jats:title>Introduction</jats:title> <jats:p> <jats:bold /> Despite the existence of institutions designed to promote peace, interactions between individuals and groups sometimes lead to conflict. Understanding the causes of such conflict is a major project in the social sciences, and researchers in anthropology, economics, geography, history, political science, psychology, and sociology have long debated the extent to which climatic changes are responsible. Recent advances and interest have prompted an explosion of quantitative studies on this question. </jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>We carried out a comprehensive synthesis of the rapidly growing literature on climate and human conflict. We examined many types of human conflict, ranging from interpersonal violence and crime to intergroup violence and political instability and further to institutional breakdown and the collapse of civilizations. We focused on quantitative studies that can reliably infer causal associations between climate variables and conflict outcomes. The studies we examined are experiments or “natural experiments”; the latter exploit variations in climate over time that are plausibly independent of other variables that also affect conflict. In many cases, we obtained original data from studies that did not meet this criterion and used a common statistical method to reanalyze these data. In total, we evaluated 60 primary studies that have examined 45 different conflict data sets. We collected findings across time periods spanning 10,000 BCE to the present and across all major world regions.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p> Deviations from normal precipitation and mild temperatures systematically increase the risk of conflict, often substantially. This relationship is apparent across spatial scales ranging from a single building to the globe and at temporal scales ranging from an anomalous hour to an anomalous millennium. Our meta-analysis of studies that examine populations in the post-1950 era suggests that the magnitude of climate’s influence on modern conflict is both substantial and highly statistically significant ( <jats:italic>P</jats:italic> &lt; 0.001). Each 1-SD change in climate toward warmer temperatures or more extreme rainfall increases the frequency of interpersonal violence by 4% and intergroup conflict by 14% (median estimates). </jats:p> </jats:sec> <jats:sec> <jats:title>Discussion</jats:title> <jats:p>We conclude that there is more agreement across studies regarding the influence of climate on human conflict than has been recognized previously. Given the large potential changes in precipitation and temperature regimes projected for the coming decades—with locations throughout the inhabited world expected to warm by 2 to 4 SDs by 2050—amplified rates of human conflict could represent a large and critical social impact of anthropogenic climate change in both low- and high-income countries.</jats:p> </jats:sec>