Catálogo de publicaciones - revistas

<jats:title>House or Face?</jats:title> <jats:p> The neural mechanisms of spatial attention are well known, unlike nonspatial attention. <jats:bold>Baldauf and Desimone</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6182" page="424" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1247003">424</jats:related-article> , published online 10 April) combined several technologies to identify a fronto-temporal network in humans that mediates nonspatial object-based attention. There is a clear top-down directionality of these oscillatory interactions, establishing the inferior-frontal cortex as a key source of nonspatial attentional inputs to the inferior-temporal cortex. Surprisingly, the mechanisms for nonspatial attention are strikingly parallel to the mechanisms of spatial attention. </jats:p>

<jats:title>No Light Control</jats:title> <jats:p> Light is the main source of energy for plants and is also used as a signal for growth and development: Indeed, it can modulate up to a fifth of the entire transcriptome in both <jats:italic>Arabidopsis thaliana</jats:italic> and rice. <jats:bold> Petrillo <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="6182" page="427" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1250322">427</jats:related-article> , published online 10 April) show that light can affect gene expression through alternative splicing of the serine-arginine rich protein <jats:italic>At-RS31</jats:italic> , required for proper plant growth. But photoreceptors are not involved; rather, a mobile retrograde signal from the chloroplast controls the alternative splicing of <jats:italic>At-RS31.</jats:italic> </jats:p>

<jats:p>The maintenance of telomeres—the structures of repetitive sequences as the end of a chromatid—is essential to the health of a cell. Dysfunction in telomere maintenance pathways plays an integral role in aging, cancer, and certain rare diseases such as dyskeratosis congenita (DC). The molecular analysis of telomere length, telomerase levels, and activation of the Alternative Lengthening of Telomeres (ALT) pathway are currently being used as prognostic tools in human diseases. This has led to telomere maintenance as a prime target for patient therapies. Studies have shown the modification of TERC (TElomerase RNA Component) expression may be therapeutically beneficial in DC patients. Additionally, current research is targeting telomere lengthening mechanisms as a cancer therapy. In this webinar, our experts will describe the advances in telomere research as it applies to human health and how deeper characterization of the telomerase maintenance process can uncover targets for therapies.</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>On this week's show: the genome sequence of the tsetse fly and a roundup of stories from our daily news site.</jats:p>

<jats:sec> <jats:title>Background</jats:title> <jats:p>Changes in Earth’s climate over time can be measured in many ways. The different metrics available represent alternative dimensions of climate change, each with distinct implications for biodiversity conservation and other sectors. However, this diversity is rarely recognized. At any given locality, average temperature or precipitation can increase or decrease, extreme values can become more intense or frequent, and the timing of specific climatic events can shift. At the same time, climatic conditions are redistributed at broader spatial extents. Across sets of localities, particular climatic conditions can become more or less available and can shift closer or farther in position at different velocities. Metrics quantifying these and other dimensions of change are commonly used in basic and applied sciences. In ecological contexts, individual metrics have helped to explain the role of past climate changes in driving species diversity or extinctions and to forecast the exposure of biodiversity to future climate changes. Yet, a comparison of the many alternative metrics in use is lacking to gain understanding of their properties and guide their use in biodiversity assessments.</jats:p> </jats:sec> <jats:sec> <jats:title>Advances</jats:title> <jats:p>Our review demonstrates that six commonly used metrics of climate change show contrasting patterns under 21st-century climate forecasts across the world. For example, whereas polar climates are projected to warm and shrink in area, the tropics see the emergence of novel climatic conditions and undergo local changes in average climates beyond past variability. To help interpret metrics of climate change, our review critically assesses the ecological implications of different metrics. Supported by examples of empirical links between observed changes in biological systems and different dimensions of climate change, we outline a conceptual framework for classification of climate change metrics according to the types of threat and opportunity they are likely to impose on biodiversity. Climate changes at the locality level are often associated with demographic threats and opportunities at the population level, whereas changes across localities can have positive or negative implications for the size and the position of species’ ranges.</jats:p> </jats:sec> <jats:sec> <jats:title>Outlook</jats:title> <jats:p>Forecasting the long-term impacts of future climate changes on biodiversity is challenging, not least because the responses of organisms are contingent on demographic, physiological, and evolutionary mechanisms, as well as on the interaction with other human-induced stressors such as habitat fragmentation. Lack of data for the majority of species on Earth further hampers the use of available bioclimatic modeling methods. By contrast, the use of simple metrics of climate change is more easily scalable to wholesale biodiversity. When appropriately implemented, such examination can provide a first-order assessment of the challenges that species are potentially exposed to, and in many circumstances, it might be the only option available.</jats:p> </jats:sec>

<jats:title>On-Demand Activity</jats:title> <jats:p> Oligodendroglia ensheath axons in the brain with myelin, which provides the insulation that speeds up transmission of neuronal electrical impulses. The process of myelination in the human brain goes on for decades, concurrent with all manner of brain development and cognitive activity. <jats:bold> Gibson <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.1252304">10.1126/science.1252304</jats:related-article> , published online 10 April; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6183" page="480" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254446"> <jats:bold>Bechler and ffrench-Constant</jats:bold> </jats:related-article> ) used optogenetics to study myelination in response to neural activity. Electrical activity in the motor cortex of the brain of awake mice led to proliferation and differentiation of oligodendrocytes and consequently increased myelination and alterations in motor response. </jats:p>