Catálogo de publicaciones - revistas

<jats:p>Nocturnal light pollution can have profound effects on humans and other organisms. Recent research indicates that nighttime outdoor lighting is increasing rapidly. Evidence from controlled laboratory studies demonstrates that nocturnal light exposure can strain the visual system, disrupt circadian physiology, suppress melatonin secretion, and impair sleep. There is a growing body of work pointing to adverse effects of outdoor lighting on human health, including the risk of chronic diseases, but this knowledge is in a more nascent stage. In this Review, we synthesize recent research on the context-specific factors and physiology relevant to nocturnal light exposure in relation to human health and society, identify critical areas for future research, and highlight recent policy steps and recommendations for mitigating light pollution in the urban environment.</jats:p>

<jats:p>The starry sky has been a source of inspiration throughout human history. Astronomy has been a common element in all cultures and civilizations, being used to establish calendars, navigate and discover new lands, and drive numerous scientific and technical breakthroughs. This Review discusses how it is becoming increasingly difficult for professional and amateur astronomers to observe the night sky because of light pollution. Artificial light at night, radio interference, and the deployment of satellite constellations are all rapidly increasing and are having adverse impacts on astronomical observations, limiting scientific discoveries, cultural connections to the night sky, and opportunities presented by astrotourism. Potential mitigation strategies to preserve the night sky are discussed.</jats:p>

<jats:p>Editors’ selections from the current scientific literature</jats:p>

<jats:p> The complex diberyllocene, CpBeBeCp (Cp, cyclopentadienyl anion), has been the subject of numerous chemical investigations over the past five decades yet has eluded experimental characterization. We report the preparation and isolation of the compound by the reduction of beryllocene (BeCp <jats:sub>2</jats:sub> ) with a dimeric magnesium(I) complex and determination of its structure in the solid state by means of x-ray crystallography. Diberyllocene acts as a reductant in reactions that form beryllium-aluminum and beryllium-zinc bonds. Quantum chemical calculations indicate parallels between the electronic structure of diberyllocene and the simple homodiatomic species diberyllium (Be <jats:sub>2</jats:sub> ). </jats:p>

<jats:p>Therapeutic oligonucleotides have emerged as a powerful drug modality with the potential to treat a wide range of diseases; however, the rising number of therapies poses a manufacturing challenge. Existing synthetic methods use stepwise extension of sequences immobilized on solid supports and are limited by their scalability and sustainability. We report a biocatalytic approach to efficiently produce oligonucleotides in a single operation where polymerases and endonucleases work in synergy to amplify complementary sequences embedded within catalytic self-priming templates. This approach uses unprotected building blocks and aqueous conditions. We demonstrate the versatility of this methodology through the synthesis of clinically relevant oligonucleotide sequences containing diverse modifications.</jats:p>

<jats:p>A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species-level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at 34 to 47% of surveyed reefs. As reefs become more shark-depleted, rays begin to dominate assemblages. Shark-dominated assemblages persist in wealthy nations with strong governance and in highly protected areas, whereas poverty, weak governance, and a lack of shark management are associated with depauperate assemblages mainly composed of rays. Without action to address these diversity deficits, loss of ecological function and ecosystem services will increasingly affect human communities.</jats:p>

<jats:p> The catalytic performance of heterogeneous catalysts can be tuned by modulation of the size and structure of supported transition metals, which are typically regarded as the active sites. In single-atom metal catalysts, the support itself can strongly affect the catalytic properties. Here, we demonstrate that the size of cerium dioxide (CeO <jats:sub>2</jats:sub> ) support governs the reactivity of atomically dispersed palladium (Pd) in carbon monoxide (CO) oxidation. Catalysts with small CeO <jats:sub>2</jats:sub> nanocrystals (~4 nanometers) exhibit unusually high activity in a CO-rich reaction feed, whereas catalysts with medium-size CeO <jats:sub>2</jats:sub> (~8 nanometers) are preferred for lean conditions. Detailed spectroscopic investigations reveal support size–dependent redox properties of the Pd-CeO <jats:sub>2</jats:sub> interface. </jats:p>