Catálogo de publicaciones - revistas

<jats:title>One dose or two?</jats:title> <jats:p> For two-dose vaccines against severe acute respiratory syndrome coronavirus 2, some jurisdictions have decided to delay the second dose to rapidly get the vaccine into more people. The consequences of deviating from manufacturer-prescribed dosing regimens are unknown but will depend on the strength of immune responses to the vaccines. Saad-Roy <jats:italic>et al.</jats:italic> took a modeling approach to tackling the inevitable uncertainties facing vaccine rollout. The authors found that although one-dose strategies generally reduce infections in the short term, in the long term, the outcome depends on immune robustness. A one-dose strategy may increase the potential for antigenic evolution if immune responses are suboptimal and the virus continues to replicate in some vaccinated people, potentially leading to immune-escape mutations. It is critical to gather serological data from vaccinated people and, to avoid negative outcomes, to ramp up vaccination efforts worldwide. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="363" related-article-type="in-this-issue" vol="372">363</jats:related-article> </jats:p>

<jats:title>Replication timing organizes epigenome</jats:title> <jats:p> The temporal order of DNA replication is conserved from yeast to humans, but its biological significance remains unclear. Klein <jats:italic>et al.</jats:italic> eliminated the protein RIF1, a master regulator of replication timing, in several human cell lines. RIF1 loss during the G1 phase of the cell cycle resulted in a heterogeneous, nearly random replication timing program from the first S phase that persisted even in stable RIF1-null clones. Altered replication timing was followed by replication-dependent redistribution of active and repressive histone modifications and alterations in genome architecture. These results support a model in which replication timing orchestrates the epigenetic state of newly replicated chromatin. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="371" related-article-type="in-this-issue" vol="372">371</jats:related-article> </jats:p>

<jats:title>Change in the air</jats:title> <jats:p> The 2016 Paris Agreement set the ambitious goals of keeping global temperature rise this century below 2°C, or even better, 1.5°C above preindustrial levels. Substantial interventions are required to meet these goals, particularly for industrialized countries. Duan <jats:italic>et al.</jats:italic> projected that China will need to reduce its carbon emissions by more than 90% and its energy consumption by almost 40% to do its share in reaching the 1.5°C target. Negative emission technology is an essential element of any plan. China's accumulated economic costs by 2050 may be about 3 to 6% of its gross domestic product. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="378" related-article-type="in-this-issue" vol="372">378</jats:related-article> </jats:p>

<jats:title>Neuronal identities</jats:title> <jats:p> Neurons of the mouse spinal cord can be identified by any of several metrics, including what neurotransmitters they use, what cells they connect to, where they are located, and what neuroprogenitor gave rise to them. Osseward <jats:italic>et al.</jats:italic> generated a different metric, genetic signatures, and identified classes of local and projection neurons that were otherwise heterogeneous by other classification systems. With this focus on a cell's genetic signature, its neurotransmitter phenotype, which is accessible by a variety of transcriptional routes, can be seen as a parallel to convergent evolution in development. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="385" related-article-type="in-this-issue" vol="372">385</jats:related-article> </jats:p>

<jats:title>Broadband thermal beaming</jats:title> <jats:p> Thermal radiation emits over a wide range of wavelengths and over a wide range of angles. Xu <jats:italic>et al.</jats:italic> constructed a material that allows a range of wavelengths to emit over a much narrower range of angles. This property allowed the authors to beam thermal energy preferentially in one direction. The strategy requires carefully exploiting stacks of epsilon-near-zero films in which the angular range of thermal emission is controlled by the film thickness. This design could be useful in thermal camouflage and passive radiative cooling applications. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="393" related-article-type="in-this-issue" vol="372">393</jats:related-article> </jats:p>

<jats:title>Adding methyl groups with good timing</jats:title> <jats:p> In pharmaceutical research, swapping out hydrogens for methyl groups is a frequent strategy to optimize small-molecule properties. Vasilopoulos <jats:italic>et al.</jats:italic> report a versatile, convenient, and comparatively safe method for methylation of carbon centers adjacent to nitrogen or aryl rings. Under carefully optimized conditions, di-tert-butyl peroxide plays a dual role as oxidant and methyl source. Cleaving the O–O bond through photosensitization produces butoxyl radicals, some of which cleave substrate C–H bonds, whereas others release methyl radicals that a nickel catalyst delivers to those activated substrates. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="398" related-article-type="in-this-issue" vol="372">398</jats:related-article> </jats:p>

<jats:title>Supersymmetric switch-on</jats:title> <jats:p> A common route to enhancing the output light from a laser system is to couple multiple lasers to form an array. However, crosstalk and interference between different modes of the individual lasers are generally detrimental to performance, leading to instabilities, and could ultimately be damaging to the laser cavities. Qiao <jats:italic>et al.</jats:italic> worked with the mathematical framework of supersymmetry, a theory developed in high-energy physics to attempt to describe the makeup and properties of particles, to design a stable two-dimensional laser array. Based on symmetry arguments, the method is scalable and could prove to be a practical platform with which to design and develop complex photonic systems. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="403" related-article-type="in-this-issue" vol="372">403</jats:related-article> </jats:p>

<jats:title>A junction for single-photon detection</jats:title> <jats:p> Josephson junctions are simple superconducting devices comprising an insulator or semiconductor separating two superconducting regions. They form the workhorse of superconducting technologies and are exquisitely sensitive to magnetic field. One long-sought proposal has been to use these devices to detect light. Walsh <jats:italic>et al.</jats:italic> have realized a photosensitive Josephson junction based on graphene that is capable of sensing single infrared photons. Such a photosensitive Josephson junction is expected to operate as a high-speed, low-power consumption optical interconnect for communication between superconducting-based supercomputers and quantum computers. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="409" related-article-type="in-this-issue" vol="372">409</jats:related-article> </jats:p>

<jats:title>Backtracking a pandemic</jats:title> <jats:p> Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may have had a history of abortive human infections before a variant established a productive enough infection to create a transmission chain with pandemic potential. Therefore, the Wuhan cluster of infections identified in late December of 2019 may not have represented the initiating event. Pekar <jats:italic>et al.</jats:italic> used genome data collected from the early cases of the COVID-19 pandemic combined with molecular clock inference and epidemiological simulation to estimate when the most successful variant gained a foothold in humans. This analysis pushes human-to-human transmission back to mid-October to mid-November of 2019 in Hubei Province, China, with a likely short interval before epidemic transmission was initiated. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6540" page="412" related-article-type="in-this-issue" vol="372">412</jats:related-article> </jats:p>