The Heisenberg limit for laser coherence

To quantify quantum optical coherence requires both the particle- and wave-natures of light. For an ideal laser beam [1,2,3], it can be thought of roughly as the number of photons emitted consecutively into the beam with the same phase. This number, $\mathfrak{C}$, can be much larger than $\mu$, the number of photons in the laser itself. The limit on $\mathfrak{C}$ for an ideal laser was thought to be of order $\mu^2$ [4,5]. Here, assuming nothing about the laser operation, only that it produces a beam with certain properties close to those of an ideal laser beam, and that it does not have external sources of coherence, we derive an upper bound: $\mathfrak{C} = O(\mu^4)$. Moreover, using the matrix product states (MPSs) method [6,7,8,9], we find a model that achieves this scaling, and show that it could in principle be realised using circuit quantum electrodynamics (QED) [10]. Thus $\mathfrak{C} = O(\mu^2)$ is only a standard quantum limit (SQL); the ultimate quantum limit, or Heisenberg limit, is quadratically better.Comment: 6 pages, 4 figures, and 31 pages of supplemental information. v2: This paper is now published [Nature Physics DOI:10.1038/s41567-020-01049-3 (26 October 2020)]. For copyright reasons, this arxiv paper is based on a version of the paper prior to the accepted (21 August 2020) versio

Ecosystem Health Education: Teaching Leadership Through Team-Based Assignments

The health and sustainability of humans, animals, and environments are interdependent. The relationship between climate change, disease emergence, and food security on sustainability of ecosystem services is embodied in the sustainable development goals (SDGs). A diverse workforce needs to be equipped with leadership skills to function in a transdisciplinary, team-based environment. Ecosystem health (ESH) provides a critical and innovative approach to solving these complex challenges and offers a toolbox to actualize SDGs. This article outlines the development of a course detailing the process of framing a new academic approach in ESH as a training pathway for undergraduate and graduate students

Shape analysis of the StW 578 calotte from Jacovec Cavern, Gauteng (South Africa)

The fossiliferous deposits within the lower-lying Jacovec Cavern in the locality of Sterkfontein yielded valuable hominin remains, including the StW 578 specimen. Because StW 578 mainly preserves the calotte, the taxonomic status of this specimen has been a matter of discussion. Within this context, here we employed high-resolution microtomography and a landmark-free registration method to explore taxonomically diagnostic features in the external surface of the StW 578 calotte. Our comparative sample included adult humans and common chimpanzees as well as one Australopithecus africanus specimen (Sts 5). We partially restored the StW 578 calotte digitally and compared it to extant specimens and Sts 5 using a landmark-free registration based on smooth and invertible surface deformation. Our comparative shape analysis reveals morphological differences with extant humans, especially in the frontal bones, and with extant chimpanzees, as well as intriguing specificities in the morphology of the StW 578 parietal bones. Lastly, our study suggests morphological proximity between StW 578 and Sts 5. Given the intimate relationship between the brain and the braincase, as well as the integration of the hominin face and neurocranium, we suggest that cranial vault shape differences between StW 578 and extant humans, if confirmed by further analyses, could be either explained by differences in brain surface morphology or in the face. Besides providing additional information about the morphology of the Jacovec calotte that will be useful in future taxonomic discussion, this study introduces a new protocol for the landmark-free analysis of fossil hominin cranial shape.Significance:• We provide further information on the enigmatic fossil specimen StW 578.• We introduce a new approach for the morphological study of fossil hominin crania.• We highlight morphological similarities between StW 578 and ‘Mrs Ples’

Humanities for the environment—A manifesto for research and action

Human preferences, practices and actions are the main drivers of global environmental change in the 21st century. It is crucial, therefore, to promote pro-environmental behavior. In order to accomplish this, we need to move beyond rational choice and behavioral decision theories, which do not capture the full range of commitments, assumptions, imaginaries, and belief systems that drive those preferences and actions. Humanities disciplines, such as philosophy, history, religious studies, gender studies, language and literary studies, psychology, and pedagogics do offer deep insights into human motivations, values, and choices. We believe that the expertise of such fields for transforming human preferences, practices and actions is ignored at society’s peril. We propose an agenda that focuses global humanities research on stepping up to the challenges of planetary environmental change. We have established Environmental Humanities Observatories through which to observe, explore and enact the crucial ways humanistic disciplines may help us understand and engage with global ecological problems by providing insight into human action, perceptions, and motivation. We present this Manifesto as an invitation for others to join the “Humanities for the Environment” open global consortium of humanities observatories as we continue to develop a shared research agenda

Lignes directrices pour de meilleures pratiques en matière de suivi de la santé et de contrôle des maladies des populations de grands singes

Ces lignes directrices ont pour objectif de fournir aux gouvernements, aux décideurs politiques, aux acteurs de la conservation, aux chercheurs, aux professionnels du tourisme de vision des grands singes et aux bailleurs de fonds des recommandations en terme de meilleures pratiques pour le suivi sanitaire des grands singes et la prévention des maladies. Ces recommandations reprennent et mettent à jour, le cas échéant, les normes antérieures de protection sanitaire recommandées par Homsy (1999). Tout en reconnaissant que le risque zéro de maladie n’existe pas et que les mesures de prévention ou de contrôle de la propagation des maladies n’élimineront jamais le risque, ces recommandations visent principalement à minimiser, plutôt qu’à tenter d’éliminer la menace de transmission de maladies des hommes aux grands singes. L’application des meilleures pratiques présentées ici devrait réduire substantiellement les risques que les activités humaines peuvent poser à la santé des grands singes, et ce faisant, envoyer un signal clair d’engagement vis-à-vis de la conservation des grands singes

Study protocol for a Randomised controlled trial of EArly transjugular intrahepatiC porTosystemic stent–shunt in Acute Variceal Bleeding (REACT-AVB trial)

Introduction: In liver cirrhosis, acute variceal bleeding (AVB) is associated with a 1-year mortality rate of up to 40%. Data on early or pre-emptive transjugular intrahepatic portosystemic stent–shunt (TIPSS) in AVB is inconclusive and may not reflect current management strategies. Randomised controlled trial of EArly transjugular intrahepatiC porTosystemic stent–shunt in AVB (REACT-AVB) aims to investigate the clinical and cost-effectiveness of early TIPSS in patients with cirrhosis and AVB after initial bleeding control.Methods and analysis: REACT-AVB is a multicentre, randomised controlled, open-label, superiority, two-arm, parallel-group trial with an internal pilot. The two interventions allocated randomly 1:1 are early TIPSS within 4 days of diagnostic endoscopy or secondary prophylaxis with endoscopic therapy in combination with non-selective beta blockers. Patients aged ≥18 years with cirrhosis and Child-Pugh Score 7–13 presenting with AVB with endoscopic haemostasis are eligible for inclusion. The primary outcome is transplant-free survival at 1 year post randomisation. Secondary endpoints include transplant-free survival at 6 weeks, rebleeding, serious adverse events, other complications of cirrhosis, Child-Pugh and Model For End-Stage Liver Disease (MELD) scores at 6 and 12 months, health-related quality of life, use of healthcare resources, cost-effectiveness and use of cross-over therapies. The sample size is 294 patients over a 4-year recruitment period, across 30 hospitals in the UK.Ethics and dissemination: Research ethics committee of National Health Service has approved REACT-AVB (reference number: 23/WM/0085). The results will be submitted for publication in a peer-reviewed journal. A lay summary will also be emailed or posted to participants before publication.Trial registration number: ISRCTN85274829; protocol version 3.0, 1 July 2023

Best Practice Guidelines for Health Monitoring and Disease Control in Great Ape Populations

First paragraph: Due to their phylogenetic relatedness, great apes and humans share susceptibility to many infectious diseases, and the potential for new diseases to be transmitted to wild great apes is of particular concern (Calvignac-Spencer et al. 2012). As great ape tourism becomes more popular, great ape research more imperative, and landscape conversion more rampant, the risk that human pathogens will be introduced to immunologically naïve wild populations becomes greater, and this could result in catastrophic losses of great apes. Therefore, it is critical that tourism and research projects involving close proximity1 between great apes and people assess the risks entailed, and establish and implement disease prevention and control measures. Disease prevention should be regarded as a top priority, recognising that it is easier and more economical to prevent the introduction of an infectious agent into a great ape population, than to attempt to treat, control or eradicate a health problem once introduced. Disease prevention programmes should be centred on monitoring health parameters, and modifying human activities accordingly, in order to reduce the risk of disease transmission to great apes. By design, such programmes will also minimise the risk of disease transfer from great apes to humans, and even from humans to other humans. Continual monitoring of the health of great apes forms the basis for establishing what is normal and abnormal and thus improves our understanding of great ape population health, allows us to determine the effectiveness of disease prevention and health management strategies, and provides a basis for conducting responsible and reasonable health interventions when needed.  To access this book go to: https://portals.iucn.org/library/node/4579

Best Practice Guidelines for Health Monitoring and Disease Control in Great Ape Populations

First paragraph: Due to their phylogenetic relatedness, great apes and humans share susceptibility to many infectious diseases, and the potential for new diseases to be transmitted to wild great apes is of particular concern (Calvignac-Spencer et al. 2012). As great ape tourism becomes more popular, great ape research more imperative, and landscape conversion more rampant, the risk that human pathogens will be introduced to immunologically naïve wild populations becomes greater, and this could result in catastrophic losses of great apes. Therefore, it is critical that tourism and research projects involving close proximity1 between great apes and people assess the risks entailed, and establish and implement disease prevention and control measures. Disease prevention should be regarded as a top priority, recognising that it is easier and more economical to prevent the introduction of an infectious agent into a great ape population, than to attempt to treat, control or eradicate a health problem once introduced. Disease prevention programmes should be centred on monitoring health parameters, and modifying human activities accordingly, in order to reduce the risk of disease transmission to great apes. By design, such programmes will also minimise the risk of disease transfer from great apes to humans, and even from humans to other humans. Continual monitoring of the health of great apes forms the basis for establishing what is normal and abnormal and thus improves our understanding of great ape population health, allows us to determine the effectiveness of disease prevention and health management strategies, and provides a basis for conducting responsible and reasonable health interventions when needed.  To access this book go to: https://portals.iucn.org/library/node/4579

When one phenotype is not enough: divergent evolutionary trajectories govern venom variation in a widespread rattlesnake species

Artículo 10 páginas, 3 figuras 1 tablaUnderstanding the origin and maintenance of phenotypic variation, particularly across a continuous spatial distribution, represents a key challenge in evolutionary biology. For this, animal venoms represent ideal study systems: they are complex, variable, yet easily quantifiable molecular phenotypes with a clear function. Rattlesnakes display tremendous variation in their venom composition, mostly through strongly dichotomous venom strategies, which may even coexist within a single species. Here, through dense, widespread population-level sampling of the Mojave rattlesnake, Crotalus scutulatus, we show that genomic structural variation at multiple loci underlies extreme geographical variation in venom composition, which is maintained despite extensive gene flow. Unexpectedly, neither diet composition nor neutral population structure explain venom variation. Instead, venom divergence is strongly correlated with environmental conditions. Individual toxin genes correlate with distinct environmental factors, suggesting that different selective pressures can act on individual loci independently of their co-expression patterns or genomic proximity. Our results challenge common assumptions about diet composition as the key selective driver of snake venom evolution and emphasize how the interplay between genomic architecture and local-scale spatial heterogeneity in selective pressures may facilitate the retention of adaptive functional polymorphisms across a continuous space.Funding: Leverhulme Trust Grant RPG 2013-315 to WW, Santander Early Career Research Scholarship to GZ, Ministerio de Economía y Competitividad Grant BFU2013-42833-P to JJC.Peer reviewe

Disease risk and conservation implications of orangutan translocations

Critically Endangered orangutans are translocated in several situations: reintroduced into historic range where no wild populations exist, released to reinforce existing wild populations, and wild-to-wild translocated to remove individuals from potentially risky situations. Translocated orangutans exposed to human diseases, including Coronavirus Disease 2019 (COVID-19), pose risks to wild and previously released conspecifics. Wildlife disease risk experts recommended halting great ape translocations during the COVID-19 pandemic to minimize risk of disease transmission to wild populations. We collected data on orangutan releases and associated disease risk management in Indonesia during the COVID-19 pandemic, and developed a problem description for orangutan disease and conservation risks. We identified that at least 15 rehabilitated ex-captive and 27 wild captured orangutans were released during the study period. Identified disease risks included several wild-to-wild translocated orangutans in direct contact or proximity to humans without protective equipment, and formerly captive rehabilitated orangutans that have had long periods of contact and potential exposure to human diseases. While translocation practitioners typically employ mitigation measures to decrease disease transmission likelihood, these measures cannot eliminate all risk, and are not consistently applied. COVID-19 and other diseases of human origin can be transmitted to orangutans, which could have catastrophic impacts on wild orangutans, other susceptible fauna, and humans should disease transmission occur. We recommend stakeholders conduct a Disease Risk Analysis for orangutan translocation, and improve pathogen surveillance and mitigation measures to decrease the likelihood of potential outbreaks. We also suggest refocusing conservation efforts on alternatives to wild-to-wild translocation including mitigating human-orangutan interactions, enforcing laws and protecting orangutan habitats to conserve orangutans in situ