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<jats:p>The benefits of global pesticide use come at the cost of their widespread occurrence in the environment. An array of abiotic and biotic transformations effectively removes pesticides from the environment, but may give rise to potentially hazardous transformation products. Despite a large body of pesticide degradation data from regulatory testing and decades of pesticide research, it remains difficult to anticipate the extent and pathways of pesticide degradation under specific field conditions. Here, we review the major scientific challenges in doing so and discuss emerging opportunities to identify pesticide degradation processes in the field.</jats:p>

<jats:p>During the past 50 years, the human population has more than doubled and global agricultural production has similarly risen. However, the productive arable area has increased by just 10%; thus the increased use of pesticides has been a consequence of the demands of human population growth, and its impact has reached global significance. Although we often know a pesticide′s mode of action in the target species, we still largely do not understand the full impact of unintended side effects on wildlife, particularly at higher levels of biological organization: populations, communities, and ecosystems. In these times of regional and global species declines, we are challenged with the task of causally linking knowledge about the molecular actions of pesticides to their possible interference with biological processes, in order to develop reliable predictions about the consequences of pesticide use, and misuse, in a rapidly changing world.</jats:p>

<jats:title>A Single-Photon Gate</jats:title> <jats:p> A long-standing goal in optics is to produce an all-optical transistor, in which the transmission of a light beam can be controlled by a single photon. Using a system in which a cloud of cesium atoms is coupled to an optical cavity, <jats:bold> Chen <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="6147" page="768" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238169">768</jats:related-article> , published online 4 July; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6147" page="725" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1242905"> <jats:bold>Volz and Rauschenbeutel</jats:bold> </jats:related-article> ) were able to control transmission through the optical cavity by exciting the atomic ensemble using a “gate” laser pulse. Just one gate photon stored was sufficient to detune the system and switch the transmission of source photons through the cavity. </jats:p>

<jats:title>A Measure of Metal-Oxide Interfaces</jats:title> <jats:p> The rate of a catalytic reaction can sometimes be enhanced by using a different metal oxide as the support for adsorbed metal nanoparticles. Such enhancement is often attributed to more active sites at the metal-oxide interface, but it can be difficult to quantify this effect. <jats:bold> Cargnello <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="6147" page="771" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240148">771</jats:related-article> , published online 18 July) synthesized monodisperse nanoparticles of nickel, platinum, and palladium and dispersed them on high-surface-area ceria or alumina supports. High-resolution transmission electron microscopy enabled a detailed analysis of interfacial site structure, which showed that the rate of CO oxidation on ceria was indeed enhanced greatly at interface sites. </jats:p>

<jats:title>Bringing Down the Andes</jats:title> <jats:p> Mountain ranges, like the Andes in South America, have a number of forces acting on them that control their elevation. High rates of precipitation can induce rapid incision of canyons, but tectonic forces from deep within the mountain range may balance or even exceed the rate of erosion. <jats:bold>Lease and Ehlers</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6147" page="774" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239132">774</jats:related-article> ) examined the exhumation histories of the northeastern Andean Plateau. The erosion of sediments older than ∼10 million years was controlled largely by tectonic processes. However, more recent sediments suggest that a shift to cooler temperatures increased precipitation 3 to 4 million years ago. </jats:p>

<jats:title>Draining Through Ice</jats:title> <jats:p> Water formed by surface melting of the Greenland Ice Sheet is transferred rapidly to the underlying bedrock, but how the water is then dispersed is less clear. This question is important because how the ice-rock interface is lubricated affects how fast the ice sheet moves. Existing conceptual models are based on observations of mountain glaciers, but <jats:bold> Meierbachtol <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="6147" page="777" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1235905">777</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6147" page="721" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1242672"> <jats:bold>Lüthi</jats:bold> </jats:related-article> ) now show that those ideas may not be applicable to the Greenland Ice Sheet. Measuring water pressures in a transect of 23 boreholes revealed that drainage structures differ between the edge, where large melt channels form, and further inland, where more distributed pathways are found. </jats:p>

<jats:title>Early Multi</jats:title><jats:p>Multituberculate mammals (multis) first arose in the Jurassic and became extinct in the Oligocene, a span of over 100 million years, which makes them the longest-living order of mammals known. This highly diverse and abundant group filled many niches occupied by today's similarly diverse rodents. Multis are known for their complex dentition and unique locomotor adaptations, which facilitated their divergence into a suite of ecosystems.<jats:bold>Yuan<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="6147" page="779" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237970">779</jats:related-article>) describe a new basal multi from a nearly complete skeleton that shows that the underpinnings of these adaptations arose early in the evolution of the order, setting the stage for the major diversification and radiation of the group that came during the Cretaceous and Paleogene.</jats:p>

<jats:title>Resistance May Not Be Futile</jats:title> <jats:p> Recently, Ug99, a particularly devastating strain of wheat stem rust fungus, has emerged, which could potentially threaten food security. Now, two genes have been cloned that offer resistance to Ug99. <jats:bold> Saintenac <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="6147" page="783" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239022">783</jats:related-article> , published online 27 June) cloned <jats:italic>Sr35 from Triticum monococcum</jats:italic> , a diploid wheat species not often cultivated. <jats:bold> Periyannan <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="6147" page="786" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239028">786</jats:related-article> , published online 27 June) cloned <jats:italic>Sr33 from Aegilops tauschii</jats:italic> , a diploid wild grass that contributed to the hexaploid genome of cultivated wheat. The genes both encode proteins that show features typical of other disease resistance proteins and offer opportunities to slow the pace of Ug99 progression. </jats:p>

<jats:title>Resistance May Not Be Futile</jats:title> <jats:p> Recently, Ug99, a particularly devastating strain of wheat stem rust fungus, has emerged, which could potentially threaten food security. Now, two genes have been cloned that offer resistance to Ug99. <jats:bold> Saintenac <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="6147" page="783" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239022">783</jats:related-article> , published online 27 June) cloned <jats:italic>Sr35 from Triticum monococcum</jats:italic> , a diploid wheat species not often cultivated. <jats:bold> Periyannan <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="6147" page="786" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239028">786</jats:related-article> , published online 27 June) cloned <jats:italic>Sr33 from Aegilops tauschii</jats:italic> , a diploid wild grass that contributed to the hexaploid genome of cultivated wheat. The genes both encode proteins that show features typical of other disease resistance proteins and offer opportunities to slow the pace of Ug99 progression. </jats:p>

<jats:title>A New Linc in Innate Immunity</jats:title> <jats:p> Long noncoding RNAs (lncRNAs) have recently emerged as important regulators of gene expression in a wide variety of biological processes, although specific roles for these molecules in the immune system have not been described. <jats:bold> Carpenter <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="6147" page="789" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240925">789</jats:related-article> , published online 1 August) now define the function of one such lncRNA in the immune system, lincRNA-Cox2. Whole-transcriptome profiling revealed that lincRNA-Cox2 was induced in mouse macrophages in response to activation of Toll-like receptors—molecules that detect microbes and alert the immune system to respond. LincRNA-Cox2 both positively and negatively regulated the expression of distinct groups of inflammatory genes. Negative regulation of gene expression was mediated by lincRNA-Cox interaction with heterogeneous nuclear ribonucleoprotein A/B and A2/B1. </jats:p>