Catálogo de publicaciones - revistas

<jats:title>The heat is on</jats:title> <jats:p> Rising surface air temperatures are understood to cause glacial melting, but it is becoming increasingly clear that the ocean also has a strong impact. Cook <jats:italic>et al.</jats:italic> studied glaciers that drain the Antarctic Peninsula and found a strong correlation between mid-depth ocean temperatures and glacier-front changes along the peninsula's western coastline. Glaciers in the south, which are exposed to warmer waters, have undergone significant retreat, while those in the northwest, which terminate in cooler waters, have not retreated as much or as uniformly. Thus, ocean-induced melting appears to be the main cause of glacial retreat in the region. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="283" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aae0017">283</jats:related-article> </jats:p>

<jats:p>The ability to identify and retain logical relations between stimuli and apply them to novel stimuli is known as relational concept learning. This has been demonstrated in a few animal species after extensive reinforcement training, and it reveals the brain’s ability to deal with abstract properties. Here we describe relational concept learning in newborn ducklings without reinforced training. Newly hatched domesticated mallards that were briefly exposed to a pair of objects that were either the same or different in shape or color later preferred to follow pairs of new objects exhibiting the imprinted relation. Thus, even in a seemingly rigid and very rapid form of learning such as filial imprinting, the brain operates with abstract conceptual reasoning, a faculty often assumed to be reserved to highly intelligent organisms.</jats:p>

<jats:title>Crossing “safe” limits for biodiversity loss</jats:title> <jats:p> The planetary boundaries framework attempts to set limits for biodiversity loss within which ecological function is relatively unaffected. Newbold <jats:italic>et al.</jats:italic> present a quantitative global analysis of the extent to which the proposed planetary boundary has been crossed (see the Perspective by Oliver). Using over 2 million records for nearly 40,000 terrestrial species, they modeled the response of biodiversity to land use and related pressures and then estimated, at a spatial resolution of ∼1 km <jats:sup>2</jats:sup> , the extent and spatial patterns of changes in local biodiversity. Across 65% of the terrestrial surface, land use and related pressures have caused biotic intactness to decline beyond 10%, the proposed “safe” planetary boundary. Changes have been most pronounced in grassland biomes and biodiversity hotspots. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="288" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf2201">288</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="220" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag1712">220</jats:related-article> </jats:p>

<jats:title>Sending neural stem cells back to the garage</jats:title> <jats:p> In the brain's hippocampus, which modulates memories and emotions, neural stem cells generate new neurons, even during adulthood. How many new neurons are generated, and when, follows from the balance between quiescence and proliferation in the pool of neural stem cells. Urbán <jats:italic>et al.</jats:italic> asked what signals send proliferating stem cells back into a quiescent state. They found that a key transcription factor that promotes cellular proliferation was degraded through the ubiquitinylation system. This molecular interaction regulated the return to a resting state, but one that was not quite as quiescent as the original state. Stem cells in this resting but primed state sustained the stem cell pool. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="292" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf4802">292</jats:related-article> </jats:p>

<jats:title>Transmitting signals across the synapse</jats:title> <jats:p> Glutamate receptors located on neuronal cells play a role in mediating electrical signals at excitatory synapses. These glutamatergic synapses are extremely important for nearly all cognitive functions. Elegheert <jats:italic>et al.</jats:italic> analyzed a complex that bridges the synapse, comprising β-neurexin 1, a cell adhesion molecule on the surface of presynaptic axons; cerebellin 1, a synaptic organizer; and the postsynaptic glutamate receptor GluD2. The structural and functional analysis provides insight into the mechanism of synaptic signaling. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="295" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aae0104">295</jats:related-article> </jats:p>

<jats:title>Epigenetic regulation in the brain</jats:title> <jats:p> The activity of neurons in the brain controls the transcription of genes that influence the pruning of dendritic connections between neurons, and such modifications can influence animal behavior. Yang <jats:italic>et al.</jats:italic> propose a role for chromatin remodeling by the nucleosome remodeling and deacetylase complex (NuRD) in the inactivation of such activity-dependent transcription in the mouse cerebellum (see the Perspective by Sweatt). Deposition of the histone variant H2A.z at promoters of activity-dependent genes required the NuRD complex. Loss of the NuRD complex function resulted in hypersensitivity of mice to sensory stimuli and excessive neuronal connectivity in animals performing a task on a treadmill. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="300" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aad4225">300</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="218" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aah4055">218</jats:related-article> </jats:p>

<jats:p> Despite advances in the field of proteomics, protein folding still remains a mystery. Yet innovations in X-ray crystallography, electron microscopy, and data analysis (think robots and Google) are yielding answers about protein structures faster than ever before. <jats:list list-type="bullet"> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/custom-publishing/technology-features/structural-biology-shapes">Read the Feature (Full-Text HTML)</jats:ext-link> </jats:p> </jats:list-item> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/sites/default/files/custom-publishing/documents/15%20July%20Proteomics%20Feature.pdf">Read the Feature (PDF)</jats:ext-link> </jats:p> </jats:list-item> <jats:list-item> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/sites/default/files/custom-publishing/douments/15%20July%20New%20Products_0.pdf">Read New Products (PDF)</jats:ext-link> </jats:p> </jats:list-item> </jats:list> </jats:p>

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