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A dearth of short-period binaries
No full textSpectroscopic observations of binary stars in globular clusters are essential to shed light on the poorly constrained period, eccentricity, and mass ratio distributions and to develop an understanding of the formation of peculiar stellar objects. 47 Tuc (NGC 104) is one of the most massive Galactic globular clusters, with a large population of blue stragglers and with many predicted but as-yet elusive stellar-mass black holes. This makes it an exciting candidate for binary searches. We present a multi-epoch spectroscopic survey of 47 Tuc with the VLT/MUSE integral field spectrograph to determine radial velocity variations for 21 699 stars. We find a total binary fraction in the cluster of (2.4 ± 1.0)%, consistent with previous photometric estimates, and an increased binary fraction among blue straggler stars, approximately three times higher than the cluster average. We find very few binaries with periods below three days, and none with massive dark companions. A comparison with predictions from state-of-the-art models shows that the absence of such short-period binaries and of binaries with massive companions is surprising, highlighting the need to improve our understanding of stellar and dynamical evolution in binary systems
Sonogenetics is a novel antiarrhythmic mechanism
No full textArrhythmia of the heart is a dangerous and potentially fatal condition. The current widely used treatment is the implantable cardioverter defibrillator (ICD), but it is invasive and affects the patient’s quality of life. The sonogenetic mechanism proposed here focuses ultrasound on a cardiac tissue, controls endogenous stretch-activated Piezo1 ion channels on the focal region’s cardiomyocyte sarcolemma, and restores normal heart rhythm. In contrast to anchoring the implanted ICD lead at a fixed position in the myocardium, the size and position of the ultrasound focal region can be selected dynamically by adjusting the signals of every piezoelectric chip on the ultrasonic phased array, and it allows novel and efficient defibrillations. Based on the developed interdisciplinary electro-mechanical model of sonogenetic treatment, our analysis shows that the proposed ultrasound intensity and frequency will be safe and painless for humans and well below the limits established by the U.S. Food and Drug Administration.National Natural Science Foundation of China 10.13039/501100001809Natural Science Basic Research Program of Shaanxi Province 10.13039/501100017596Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. 10.13039/501100017596Deutsches Zentrum für Herz-Kreislaufforschung 10.13039/100010447Bundesministerium für Bildung und Forschung 10.13039/50110000234
Starch-rich plant foods 780,000 y ago: Evidence from Acheulian percussive stone tools
No full textIn contrast to animal foods, wild plants often require long, multistep processing techniques that involve significant cognitive skills and advanced toolkits to perform. These costs are thought to have hindered how hominins used these foods and delayed their adoption into our diets. Through the analysis of starch grains preserved on basalt anvils and percussors, we demonstrate that a wide variety of plants were processed by Middle Pleistocene hominins at the site of Gesher Benot Ya’aqov in Israel, at least 780,000 y ago. These results further indicate the advanced cognitive abilities of our early ancestors, including their ability to collect plants from varying distances and from a wide range of habitats and to mechanically process them using percussive tools.EC | European Research Council 50110000078
Nutrient Digestibility in Zoo‐Kept Tapirs ( Tapirus spp) as Compared to Other Herbivores
No full textABSTRACT Tapirs are hindgut fermenters with a natural diet dominated by browse, with a certain proportion of wild fruit. By contrast, diets fed to tapirs in zoos are often dominated by domestic fruit and other sources of easily digestible carbohydrates, which have been linked to obesity and various health problems. We aimed at better understanding the digestive physiology of tapirs, measuring the digestive efficiency of 13 lowland ( Tapirus terrestris ) and five Malayan ( Tapirus indicus ) tapirs from five zoos on various zoo diets by recording intake and total faecal excretion. Additionally, we aimed at evaluating zoo diets, by assessing relationships between dietary characteristics and data on intake and faeces consistency, and compared the data gained in the zoo study to those of faecal samples of free‐ranging tapirs. Tapirs showed digestive principles reported in other herbivores, such as higher levels of metabolic faecal nitrogen and a lower intake on diets of higher digestibility, or a decrease in digestibility with increasing dietary fibre concentrations. Compared to horses or grazing rhinoceroses, organic matter digestibility in tapirs was more negatively affected by dietary fibre; additionally, tapirs had comparatively low fibre digestibility. This is possibly linked to their comparatively poor chewing efficacy. The readiness to ingest a hay‐only diet was directly proportional to the amount of hay in the usual zoo diet, supporting reports that it may be difficult to achieve high hay intakes in tapirs instantaneously. Faeces consistency was closer to the natural condition with higher proportions of roughage in the diet. Compared to a set of faecal samples from the wild, zoo faeces were generally lower in fibre. This study supports previous suggestions that zoo tapirs could benefit, in terms of mimicking their digestive physiology and feeding behaviour in natural habitats, from diets based on a readily ingested roughage source, especially from browse
Why oaks should stay with their close relatives: growing in a distantly related neighbourhood delays and reorganizes nutrient recycling during litter decomposition
No full textClosely related species often conserve similar niches despite interacting negatively. We suggest that close relatives may interact positively via ecosystem feedbacks: leaf litter produced or exposed in a closely related neighbourhood (low phylogenetic isolation) may decompose more quickly, leading to more rapid nutrient recycling. We studied decomposition of leaf litter of oaks Quercus petraea across 8 and 14 months, reciprocally transplanting leaf litters between low and high phylogenetic isolation to distinguish between effects mediated by leaf litter quality and by decomposition environment. We found that, by affecting litter quality, phylogenetic isolation reduced decomposition across 14 months (loss of litter mass and C). Moreover, by affecting litter quality and decomposition environment, phylogenetic isolation reduced microbial biomass and extensively altered relationships between C and N losses and abundances/diversities of different soil organisms across 8 and 14 months. Phylogenetic isolation was to a large extant driven by percentage of gymnosperms, explaining the decomposition‐environment mediated effects. Such environment‐mediated effects reflected decreasing soil humidity and pH with phylogenetic isolation, while litter‐quality mediated effects reflected decreasing leaf phytophagy or increasing leaf phenolics. Tree‐species richness, in contrast, did not explain effects of phylogenetic isolation, and had little effect overall. To conclude, coexistence of oaks with distant relatives partly impedes recycling of leaf litter and re‐organizes the trajectories of this recycling. In contrast, oaks coexisting with close relatives may profit from a positive ecosystem feedback through increased nutrient recycling, possibly contributing to the conservation of the oak's niches. We suggest that such a positive ecosystem feedback among close relatives might exist in other late successional tree species
Mechanical thrombectomy in elderly stroke patients with low ASPECTS: insights from STAR
No full textBackground The elderly population (≥80 years) were underrepresented in recent trials of endovascular thrombectomy (EVT) for anterior circulation large vessel occlusion acute ischemic stroke (LVO-AIS) with low Alberta Stroke Program Early CT Score (ASPECTS) (≤5). Methods This study analyzed data from a prospectively maintained database of 37 thrombectomy centers. The primary cohort of the study comprised patients with LVO-AIS aged ≥80 who underwent EVT with ASPECTS≤5 from 2013 to 2023. The primary outcome was favorable modified Rankin Scale (mRS) score of 0–3. Propensity score matching (PSM) and multivariate regression were applied. Results In a study of 14 233 patients undergoing EVT, 1741 patients were 80 or older, with 122 presenting with low ASPECTS. While successful recanalization rates were similar between age groups, patients aged ≥80 had significantly lower favorable 90-day mRS scores and higher mortality before propensity score matching (PSM). After PSM, differences in mortality and symptomatic intracranial hemorrhage (sICH) were no longer significant. Among all elderly patients, higher ASPECTS was an independent predictor of a 90-day favorable outcome but was not associated with 90-day mortality. For patients aged ≥80 years with low ASPECTS, favorable outcomes were associated only with lower rates of atrial fibrillation, baseline functioning (mRS 0–1), fewer thrombectomy passes, and higher likelihood of first-pass reperfusion within 30 min of puncture. Conclusion While age ≥80 increases mortality and disability in patients with AIS and low ASPECTS, select elderly patients may still benefit from EVT when clinical factors are considered, supporting individualized treatment and better patient selection for future trials.http://dx.doi.org/10.13039/100008894 StrykerRapidAIhttp://dx.doi.org/10.13039/100013490 Brain Aneurysm Foundationhttp://dx.doi.org/10.13039/100020501 PenumbraMicroventionMedtroni
Trazodone, dibenzoylmethane and tauroursodeoxycholic acid do not prevent motor dysfunction and neurodegeneration in Marinesco-Sjögren syndrome mice
No full textThere is no cure for Marinesco-Sjögren syndrome (MSS), a genetic multisystem disease linked to loss-of-function mutations in the SIL1 gene, encoding a BiP co-chaperone. Previously, we showed that the PERK kinase inhibitor GSK2606414 delays cerebellar Purkinje cell (PC) degeneration and the onset of ataxia in the woozy mouse model of MSS. However, GSK2606414 is toxic to the pancreas and does not completely rescue the woozy phenotype. The present study tested trazodone and dibenzoylmethane (DBM), which partially inhibit PERK signaling with neuroprotective effects and no pancreatic toxicity. We also tested the chemical chaperone tauroursodeoxycholic acid (TUDCA), which protects MSS patients’ cells from stress-induced apoptosis. Mice were chronically treated for five weeks, starting from a presymptomatic stage. Trazodone was given 40 mg/kg daily by intraperitoneal (ip) injection. DBM was given 0.5% in the diet ad libitum. TUDCA was given either 0.4% in the diet, or 500 mg/kg ip every three days. None of the treatments prevented motor dysfunction or PC degeneration in woozy mice, as assessed by beam walking, rotarod test, and calbindin immunohistochemistry. Only trazodone slightly boosted beam walking performance, but this effect was not related to inhibition of PERK signaling. Pharmacokinetic studies excluded that the lack of effect was due to altered drug metabolism in woozy mice. These results indicate that trazodone, DBM and TUDCA, at dosing regimens active in other neurodegenerative disease mouse models, have no disease-modifying effect in a preclinical model of MSS. This underscores the difficulty of translating neuroprotective strategies from other conditions to MSS, highlighting the need for more targeted therapeutic approaches.Fondazione Telethon http://dx.doi.org/10.13039/501100002426European Union 50110000078
Super‐Resolution Goes Viral: T4 Virus Particles as Versatile 3D‐Bio‐NanoRulers
No full textAbstract In the burgeoning field of super‐resolution fluorescence microscopy, significant efforts are being dedicated to expanding its applications into the 3D domain. Various methodologies have been developed that enable isotropic resolution at the nanometer scale, facilitating the visualization of 3D subcellular structures with unprecedented clarity. Central to this progress is the need for reliable 3D structures that are biologically compatible for validating resolution capabilities. Choosing the optimal standard poses a considerable challenge, necessitating, among other attributes, precisely defined geometry and the capability for specific labeling at sub‐diffraction‐limit distances. In this context, the use of the non‐human‐infecting virus, bacteriophage T4 is introduced as an effective and straightforward bio‐ruler for 3D super‐resolution imaging. Employing DNA point accumulation for imaging in nanoscale topography (DNA‐PAINT) along with the technique of astigmatic imaging, the icosahedral capsid of the bacteriophage T4, measuring 120 nm in length and 86 nm in width, and its hollow viral tail is uncovered. This level of detail in light microscopy represents a significant advancement in T4 imaging. A simple protocol for the production and preparation of samples is further outlined. Moreover, the extensive potential of bacteriophage T4 as a multifaceted 3D bio‐ruler, proposing its application as a novel benchmark for 3D super‐resolution imaging in biological studies is explored.European Commission https://doi.org/10.13039/501100000780H2020 European Research Council https://doi.org/10.13039/100010663Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659HORIZON EUROPE Marie Sklodowska-Curie Actions https://doi.org/10.13039/10001869
When AI-Based Agents Are Proactive: Implications for Competence and System Satisfaction in Human–AI Collaboration
No full textAbstract As the capabilities of artificial intelligence (AI) technologies continue to improve, collaboration with AI-based agents enables users to be more efficient and productive. Not only has the quality of AI-based agents’ outcomes increased, but they can now help proactively, and even take over entire work tasks. However, users need to be satisfied with the system to remain motivated to collaborate and engage with AI-based agents. Drawing on self-determination theory, a vignette-based online experiment was conducted that revealed that proactive (vs. reactive) help from AI-based agents leads to a higher loss of users’ competence-based self-esteem and thus reduces users’ system satisfaction. This effect is moderated by the users’ knowledge of AI. Higher (vs. lower) levels of AI knowledge cause a greater loss of competence-based self-esteem through proactive (vs. reactive) help. The findings contribute to a better understanding of help from AI-based agents and provide important implications for managers and designers who seek to enhance human–AI collaboration