Catálogo de publicaciones - revistas

<jats:title>The most luminous supernova to date</jats:title> <jats:p> Supernovae are exploding stars at the end of their lives, providing an input of heavy elements and energy into galaxies. Some types have near-identical peak brightness, but in recent years a new class of superluminous supernovae has been found. Dong <jats:italic>et al.</jats:italic> y report the discovery of ASASSN-15lh (SN 2015L), the most luminous supernova yet found by some margin. It appears to originate in a large quiescent galaxy, in contrast to most super-luminous supernovae, which typically come from star-forming dwarf galaxies. The discovery will provide constraints on models of superluminous supernovae and how they affect their host galaxies. </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="6270" page="257" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac9613">257</jats:related-article> </jats:p>

<jats:title>Earliest human Arctic occupation</jats:title> <jats:p> Paleolithic records of humans in the Eurasian Arctic (above 66°N) are scarce, stretching back to 30,000 to 35,000 years ago at most. Pitulko <jats:italic>et al.</jats:italic> have found evidence of human occupation 45,000 years ago at 72°N, well within the Siberian Arctic. The evidence is in the form of a frozen mammoth carcass bearing many signs of weapon-inflicted injuries, both pre- and postmortem. The remains of a hunted wolf from a widely separate location of similar age indicate that humans may have spread widely across northern Siberia at least 10 millennia earlier than previously thought. </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="6270" page="260" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad0554">260</jats:related-article> </jats:p>

<jats:title>Using solar energy suboptimally</jats:title> <jats:p> How efficient are phytoplankton at converting sunlight into the products of photosynthesis? The two other pathways that that absorbed energy can take are emission back to the environment by fluorescence or conversion to heat. Lin <jats:italic>et al.</jats:italic> measured phytoplankton fluorescence lifetimes in the laboratory and combined them with satellite measurements of variable chlorophyll fluorescence. Combined, they determined the quantum yields of photochemistry and fluorescence in four ocean basins. Approximately 60% of absorbed solar energy is converted to heat, a figure 50% higher than has been determined for conditions of optimal growth. </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="6270" page="264" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aab2213">264</jats:related-article> </jats:p>

<jats:title>Fixation on learned syllables</jats:title> <jats:p> Zebra finches learn their beautiful songs by listening to other zebra finches. Vallentin <jats:italic>et al.</jats:italic> observed zebra finch brains as learning proceeded, only to find that inhibition of the neuronal circuits was critical to fixating on learned sequences. For song syllables that have been adequately learned, the inhibitory neurons fired coherently. Song syllables not yet learned failed to produce this flag. Thus, it is the learning process that alters the neuronal circuits. The inhibitory neuronal firing, not the age of the bird, locks in the learning. </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="6270" page="267" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad3023">267</jats:related-article> </jats:p>

<jats:title>Another micropeptide flexes its muscle</jats:title> <jats:p> Genome annotation is a complex but imperfect art. Attesting to its limitations is the growing evidence that certain transcripts annotated as long noncoding RNAs (lncRNAs) in fact code for small peptides with biologically important functions. One such lncRNA-derived micropeptide in mammals is myoregulin, which reduces muscle performance by inhibiting the activity of a key calcium pump. Nelson <jats:italic>et al.</jats:italic> describe the opposite activity in a second lncRNA-derived micropeptide in mammalian muscle, called DWORF (see the Perspective by Payre and Desplan). This peptide enhances muscle performance by activating the same calcium pump. DWORF may prove to be useful in improving the cardiac muscle function of mammals with heart disease. </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="6270" page="271" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad4076">271</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6270" page="226" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad9873">226</jats:related-article> </jats:p>

<jats:title>How to shape mitochondrial networks</jats:title> <jats:p> Mitochondria undergo fragmentation or fusion in response to changes in cellular metabolism. Toyama <jats:italic>et al.</jats:italic> report that adenosine monophosphate-activated protein kinase (AMPK) is both necessary and sufficient to control mitochondrial fragmentation. AMPK functions as a sensor to monitor the energy status of the cell by phosphorylating mitochondrial fission factor (MFF), a protein of the mitochondrial outer membrane. MFF then acts to recruit a cytoplasmic guanosine triphosphatase that promotes mitochondrial fission. </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="6270" page="275" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aab4138">275</jats:related-article> </jats:p>

<jats:title>Chemical modification of RNA for function</jats:title> <jats:p> Chemical modifications play an important role in modifying and regulating the function of DNA and RNA. Delatte <jats:italic>et al.</jats:italic> show that, in the fruit fly, many messenger RNAs (mRNAs) contain the modified base 5-hydroxymethylcytosine (5hmC). The chemical mark is added by the same enzyme that adds 5hmC to DNA. Because many mRNAs involved in neuronal development contain 5hmC, blocking the enzyme causes brain defects and is lethal. In vivo, RNA hydroxymethylation promotes mRNA translation. </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="6270" page="282" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aac5253">282</jats:related-article> </jats:p>

<jats:title>Reactivating the fetal globin gene</jats:title> <jats:p> Mutation of adult-type globin genes causes sickle cell disease and thalassemia. Although treating these hemoglobinopathies with gene therapy is possible, there is a pressing need for pharmacologic approaches to treat general patient populations. One promising approach is to reactivate repressed expression of fetal-type hemoglobin (HbF) in adult erythroid cells. Masuda <jats:italic>et al.</jats:italic> reveal a molecular mechanism governing HbF repression as mediated by the LRF/ZBTB7A transcription factor. The study may encourage the development of new HbF reactivation therapies for hemoglobinopathies. </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="6270" page="285" related-article-type="in-this-issue" vol="351" xlink:href="10.1126/science.aad3312">285</jats:related-article> </jats:p>

<jats:p> Devices to prepare cells, nucleic acids, proteins, and other samples for analysis are becoming increasingly sophisticated, running faster and more accurately than ever before. In addition, their ease of use is making it possible to quickly train almost anyone to run automated sample preparation. <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/automated-sample-preparation">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-Jan-Automated-Sample-Prep.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-Jan-New-Products_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>