198 research outputs found

    Enhanced Leaf Cooling Is a Pathway to Heat Tolerance in Common Bean

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    Common bean is the most consumed legume in the world and an important source of protein in Latin America, Eastern, and Southern Africa. It is grown in a variety of environments with mean air temperatures of between 14°C and 35°C and is more sensitive to high temperatures than other legumes. As global heating continues, breeding for heat tolerance in common bean is an urgent priority. Transpirational cooling has been shown to be an important mechanism for heat avoidance in many crops, and leaf cooling traits have been used to breed for both drought and heat tolerance. As yet, little is known about the magnitude of leaf cooling in common bean, nor whether this trait is functionally linked to heat tolerance. Accordingly, we explore the extent and genotypic variation of transpirational cooling in common bean. Our results show that leaf cooling is an important heat avoidance mechanism in common bean. On average, leaf temperatures are 5°C cooler than air temperatures, and can range from between 13°C cooler and 2°C warmer. We show that the magnitude of leaf cooling keeps leaf temperatures within a photosynthetically functional range. Heat tolerant genotypes cool more than heat sensitive genotypes and the magnitude of this difference increases at elevated temperatures. Furthermore, we find that differences in leaf cooling are largest at the top of the canopy where determinate bush beans are most sensitive to the impact of high temperatures during the flowering period. Our results suggest that heat tolerant genotypes cool more than heat sensitive genotypes as a result of higher stomatal conductance and enhanced transpirational cooling. We demonstrate that it is possible to accurately simulate the temperature of the leaf by genotype using only air temperature and relative humidity. Our work suggests that greater leaf cooling is a pathway to heat tolerance. Bean breeders can use the difference between air and leaf temperature to screen for genotypes with enhanced capacity for heat avoidance. Once evaluated for a particular target population of environments, breeders can use our model for modeling leaf temperatures by genotype to assess the value of selecting for cooler beans

    Faculty bridging individual and organizational resilience: results of a qualitative analysis

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    Background: Medical student burnout and anxiety has received growing attention in the past decade. The culture of competition and assessment has resulted in increasing stress levels amongst medical students, causing a decline in their academic performance and overall mental health. The objective of this qualitative analysis was to characterize recommendations from educational experts to aid students’ academic progress. Methods: At an international meeting in 2019, worksheets were completed by medical educators during a panel discussion. Participants responded to four scenarios representing common challenges medical students face in school (eg. Postponing Step 1, failing clerkships, etc.). For each case, participants addressed what students, faculty and medical schools could do to mitigate the challenge. Inductive thematic analysis was conducted by two authors followed by deductive categorization using an individual-organizational resilience model. Results: Across the four cases, common suggestions made for students, faculty and medical schools were aligned to a resilience model representing the complex interplay between individuals and organizations and the impact on student wellbeing. Discussion: Using suggestions from medical educators from across the US, we were able to identify recommendations for students, faculty, and medical schools to help students succeed in medical school. By applying a model of resilience, faculty serve as a critical bridge to connect students to the medical school administration. Our findings also support a pass/fail curriculum to ease the competition and burden students place on themselves

    SLoMo: A General System for Legged Robot Motion Imitation from Casual Videos

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    We present SLoMo: a first-of-its-kind framework for transferring skilled motions from casually captured "in the wild" video footage of humans and animals to legged robots. SLoMo works in three stages: 1) synthesize a physically plausible reconstructed key-point trajectory from monocular videos; 2) optimize a dynamically feasible reference trajectory for the robot offline that includes body and foot motion, as well as contact sequences that closely tracks the key points; 3) track the reference trajectory online using a general-purpose model-predictive controller on robot hardware. Traditional motion imitation for legged motor skills often requires expert animators, collaborative demonstrations, and/or expensive motion capture equipment, all of which limits scalability. Instead, SLoMo only relies on easy-to-obtain monocular video footage, readily available in online repositories such as YouTube. It converts videos into motion primitives that can be executed reliably by real-world robots. We demonstrate our approach by transferring the motions of cats, dogs, and humans to example robots including a quadruped (on hardware) and a humanoid (in simulation). To the best knowledge of the authors, this is the first attempt at a general-purpose motion transfer framework that imitates animal and human motions on legged robots directly from casual videos without artificial markers or labels.Comment: accepted at RA-L 2023, with ICRA 2024 optio

    Basis-independent methods for the two-Higgs-doublet model II. The significance of tan(beta)

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    In the most general two-Higgs-doublet model (2HDM), there is no distinction between the two complex hypercharge-one SU(2) doublet scalar fields, Phi_a (a=1,2). Thus, any two orthonormal linear combinations of these two fields can serve as a basis for the Lagrangian. All physical observables of the model must therefore be basis-independent. For example, tan(beta)=/ is basis-dependent and thus cannot be a physical parameter of the model. In this paper, we provide a basis-independent treatment of the Higgs sector with particular attention to the neutral Higgs boson mass-eigenstates, which generically are not eigenstates of CP. We then demonstrate that all physical Higgs couplings are indeed independent of tan(beta). In specialized versions of the 2HDM, tan(beta) can be promoted to a physical parameter of the Higgs-fermion interactions. In the most general 2HDM, the Higgs-fermion couplings can be expressed in terms of a number of physical "tan(beta)--like" parameters that are manifestly basis-independent. The minimal supersymmetric extension of the Standard Model provides a simple framework for exhibiting such effects.Comment: 56 pages, 5 tables, with Eq. (65) corrected (erratum to appear in Physical Review D

    Lipohypertrophy due to HAART: a case series

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    A subset of HIV-1 infected patients undergoing Highly Active Antiretroviral Therapy (HAART) develops a lipodystrophy syndrome. It is characterised by loss of subcutaneous adipose tissue (face, limbs and buttocks) visceral fat accumulation and lipomatosis especially in dorsocervical area. In addition these patients show metabolic alteration implicative of metabolic syndrome particularly dyslipidaemia and insulin resistance. These alterations lead to enhanced cardiovascular risk and favour the development of diabetes in such patients. A complex combination of HIV infection, drug treatment related events and lipotoxicity appears to contribute to the development of lipodystrophy syndrome. Active lipolysis in subcutaneous fat combined with impaired storage capacity in subcutaneous depot leads to ectopic deposition of lipids either in visceral or in non-adipose sites. Lipotoxicity, a pathogenic factor in the lipodystrophy syndrome should be considered in the strategies for treating and /or preventing the morphological alterations and systemic metabolic disturbances associated with lipodystrophy

    A case series of cefixime induced Steven’s Johnson Syndrome

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    Drug induced adverse reactions are a major health problem. Drug hyper sensitivity reactions manifest themselves in many diseases, of which some are very severe. The most common allergic reactions occur in the skin. Stevens-Johnson syndrome is mainly caused by drugs (antimicrobials e.g.: penicillin’s, sulphonamides and cephalosporin’s e.g.: cefixime, antiepileptic’s, NSAIDS), infections and also by other risk factors not yet identified. The most common allergic reactions occur in the skin. These reactions ranging from simple pruritic eruptions to potentially life threatening events are a significant cause of iatrogenic morbidity and mortality. Identification of the cause, withdrawal of the trigger and supportive management is crucial to improve the patient state. Despite of all therapeutic efforts, mortality is high and increases with disease severity, patient’s age and underlying medical conditions. Survivors may suffer from long-term squeal such as strictures of mucous membranes including severe eye problems

    A new framework for predicting and understanding flowering time for crop breeding

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    As the growing season changes, the development of climate resilient crop varieties has emerged as a crucial adaptation in agricultural systems. Breeding new varieties for a changing climate requires enhanced capacity to predict the complex interactions between genotype and environment that determine flowering time. Hundreds of experiments with observations of flowering, the environment and plant genetics were used to build a model that can predict when a variety of common bean is going to flower. This model will help breeders to explore the phenological characteristics of their germplasm, speeding up selection for climate adaptation.Summary•There is an urgent need to accelerate crop breeding for adaptation to a changing climate. As the growing season changes, crop improvement programmes must ensure that the phenological characteristics of the varieties they develop remain well suited to their target population of environments.•Meeting this challenge will require a clear understanding of how existing germ-plasm behave across Genotype∗Environment (G∗E) to enhance the efficiency of selection. Recent work calls for the development of simple models that can accu-rately simulate genotypic variation in key traits across target population of environments.•Accordingly, we develop a simple machine learning framework for modelling time to flowering across G∗E and apply this to common bean in an equatorial target population of environments. Within this framework, we test three machine learn-ing models and find that the best performing models display high levels of accu-racy across G∗E.•We advance understanding of the environmental drivers of flowering time inequatorial conditions by showing that thermal time and accumulated evaporation are powerful predictors of flowering time across all three models

    Graph Regionalization with Clustering and Partitioning: an Application for Daily Commuting Flows in Albania

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    The paper presents an original application of the recently proposed spatial data mining method named GraphRECAP on daily commuting flows using 2011 Albanian census data. Its aim is to identify several clusters of Albanian municipalities/communes; propose a classification of the Albanian territory based on daily commuting flows among municipalities/communes. Starting from 373 local units, we first applied a spatial clustering technique without imposing any constraining strategy. Based on the input variables, we obtained 16 clusters. In the second step of our analysis, we impose a set of constraining parameters to identify intermediate areas between the local level (municipality/commune) and the national one. We have defined 12 derived regions (same number as the actual Albanian prefectures but with different geographies). These derived regions are quite different from the traditional ones in terms of both geographical dimensions and boundarie

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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