1,963 research outputs found
Optical Characterization of a Single Quantum Emitter Based on Vanadium Phthalocyanine Molecules
Single quantum emitters play a fundamental role in the development of quantum
technologies such as quantum repeaters, and quantum information processing.
Isolating individual molecules with stable optical emission is an essential
step for these applications, specially for those molecules that present large
coherence times at room temperature. Among them, vanadium-oxide phthalocyanine
(VOPc) molecules stand out as promising candidates due to their large coherence
times measured in ensemble. However, the optical properties of individual
molecules have not yet been reported. Here we show that single VOPc molecules
with stable optical properties at room temperature can be isolated. We find
that the optical response of the molecule under laser illumination of different
polarization agrees well with a system having pyramidal C symmetry.
Furthermore, the molecule reveals a non-radiative transition rate that depends
on the excitation wavelength when its lifetime is interrogated. We provide
theoretical calculations that support our experimental findings and provide
insight to the role of phonons and internal electronic structure of the
molecule. These results demonstrate that this single paramagnetic molecule can
function as a single quantum emitter while displaying optical stability under
ambient conditions to have their intrinsic properties investigated
Decadal changes and delayed avian species losses due to deforestation in the northern Neotropics
How avifauna respond to the long-term loss and fragmentation of tropical forests is a critical issue in biodiversity management. We use data from over 30 years to gain insights into such changes in the northernmost Neotropical rainforest in the Sierra de Los Tuxtlas of southern Veracruz, Mexico. This region has been extensively deforested over the past half-century. The Estación de Biología Tropical Los Tuxtlas, of the Universidad Nacional Autónoma de México (UNAM), protects a 640 ha tract of lowland forest. It became relatively isolated from other forested tracts between 1975 and 1985, but it retains a corridor of forest to more extensive forests at higher elevations on Volcán San Martín. Most deforestation in this area occurred during the 1970s and early 1980s. Forest birds were sampled on the station and surrounding areas using mist nets during eight non-breeding seasons from 1973 to 2004 (though in some seasons netting extended into the local breeding season for some species). Our data suggested extirpations or declines in 12 species of birds subject to capture in mist nets. Six of the eight species no longer present were captured in 1992–95, but not in 2003–2004. Presence/absence data from netting and observational data suggested that another four low-density species also disappeared since sampling began. This indicates a substantial time lag between the loss of habitat and the apparent extirpation of these species. Delayed species loss and the heterogeneous nature of the species affected will be important factors in tropical forest management and conservation
Nivel de actividad física en estudiantes universitarios del Norte de la Ciudad de Lima
Objetivos: Evaluar el nivel de actividad física (AF) en los estudiantes universitarios de Lima Norte. Materiales y métodos: Estudio descriptivo transversal. Participaron estudiantes procedentes de una universidad privada ubicada al Norte de la ciudad de Lima. El estudio se realizó en el segundo semestre del periodo académico 2020. Como instrumento de medición se utilizó el Cuestionario Internacional de Actividad Física (IPAQ). Resultados: Participaron 354 estudiantes de ambos sexos, con una mediana de edad de 23 años (rango intercuartilar: 29-20), el 61,9% (n=219) de sexo femenino, el 34,7% (n=123) tenían entre 20 a 24 años de edad. El 57, 6% de los estudiantes presentaron AF moderada y el 29, 9% AF baja. En los varones, el nivel de AF moderada, vigorosa y AF total fue de 300, 600 y 1358 MET-minutos/semana, respectivamente; mientras que en las mujeres fue de 200, 280 y 986,5 MET-minutos/semana, respectivamente (p<0,001). La frecuencia de AF baja fue mayor en las mujeres respecto a los varones (p<0,001). La AF baja se presentó en mayor proporción en estudiantes menores de 30 años (p=0,008), en los solteros (p=0,005) y en estudiantes de ciencias de la salud (p=0,002). Conclusiones: En los estudiantes universitarios hubo predominio de la AF moderada; sin embargo, 3 de cada 10 estudiantes presentaron bajo nivel de AF. Se recomienda la promoción de alternativas de actividad física en la comunidad universitaria
A systematic review and meta-analysis of the effect of dispatcher-assisted CPR on outcomes from sudden cardiac arrest in adults and children
Background: Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) has been reported in individual studies to significantly increase the rate of bystander CPR and survival from cardiac arrest. Methods: We undertook a systematic review and meta-analysis to evaluate the impact of DA-CPR programs on key clinical outcomes following out-of-hospital cardiac arrest. We searched the PubMED, EMBASE, CINAHL, ERIC and Cochrane Central Register of Controlled Trials databases from inception until July 2018. Eligible studies compared systems with and without dispatcher-assisted CPR programs. The results of included studies were classified into 3 categories for the purposes of more accurate analysis: comparison of outcomes in systems with DA-CPR programs, case-based comparison of DA-CPR to bystander CPR, and case-based comparisons of DA-CPR to no CPR before EMS arrival. The GRADE system was used to assess certainty of evidence at an outcome level. We used random-effects models to produce summary effect sizes across all outcomes. Results: Of 5531 citations screened, 33 studies were eligible for inclusion. All included studies were observational. Evidence certainty across all outcomes was assessed as low or very low. In system-level and patient-level comparisons, the provision of DA-CPR compared with no DA-CPR was consistently associated with improved outcome across all analyses. Comparison of DA-CPR to bystander CPR produced conflicting results. Findings were consistent across sensitivity analyses and the pediatric sub-group. Conclusion: These results support the recommendation that dispatchers provide CPR instructions to callers for adults and children with suspected OHCA. Review registration: PROSPERO- CRD42018091427
2018: Art & Mobilities Network Inaugural Symposium Instant Journal (Peter Scott Gallery)
"Mobilities has been gaining momentum through networks, conferences, books, special issues, exhibitions and in the practices of artists, writers and curators. In recognition of this activity we are forming an Art & Mobilities network through which to consolidate, celebrate and develop this work.Inspired by the recent foregrounding of Mobility and the Humanities (Pearce & Merriman, 2018) and drawing on last November's successful Mobile Utopia Exhibition amongst others, the Centre for Mobilities Research (CEMORE) at Lancaster University are pleased to hold a UK Art & Mobilities Network Inaugural Symposium 2018 on the 3rd of July 2018.
The aim of the symposium is to bring together people in the UK who are active in the field of mobilities and art in order to discuss the distinctive contribution that art makes to mobilities research and vice versa. We would be delighted if you can join us for this one-day event to help shape the network, particularly in the context of a fast-changing world, not just socio-politically but in terms of the place of art in the academy and vice versa.
There are nearly 30 key international artists and researchers gathered on this day both locally and via Skype. We invite all participants in the symposium to bring with them an artwork, artefact, written statement or quote that can be displayed as a ‘pop up’ exhibition. These artefacts will be used during the day to focus discussion around different facets of mobilities and art." (Jen Southern, Kai Syng Tan, Emma Rose, Linda O'Keeffe Editors
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
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
Modulations of the Chicken Cecal Microbiome and Metagenome in Response to Anticoccidial and Growth Promoter Treatment
With increasing pressures to reduce or eliminate the use of antimicrobials for growth promotion purposes in production animals, there is a growing need to better understand the effects elicited by these agents in order to identify alternative approaches that might be used to maintain animal health. Antibiotic usage at subtherapeutic levels is postulated to confer a number of modulations in the microbes within the gut that ultimately result in growth promotion and reduced occurrence of disease. This study examined the effects of the coccidiostat monensin and the growth promoters virginiamycin and tylosin on the broiler chicken cecal microbiome and metagenome. Using a longitudinal design, cecal contents of commercial chickens were extracted and examined using 16S rRNA and total DNA shotgun metagenomic pyrosequencing. A number of genus-level enrichments and depletions were observed in response to monensin alone, or monensin in combination with virginiamycin or tylosin. Of note, monensin effects included depletions of Roseburia, Lactobacillus and Enterococcus, and enrichments in Coprococcus and Anaerofilum. The most notable effect observed in the monensin/virginiamycin and monensin/tylosin treatments, but not in the monensin-alone treatments, was enrichments in Escherichia coli. Analysis of the metagenomic dataset identified enrichments in transport system genes, type I fimbrial genes, and type IV conjugative secretion system genes. No significant differences were observed with regard to antimicrobial resistance gene counts. Overall, this study provides a more comprehensive glimpse of the chicken cecum microbial community, the modulations of this community in response to growth promoters, and targets for future efforts to mimic these effects using alternative approaches
2017 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations Summary
The International Liaison Committee on Resuscitation has initiated a near-continuous review of cardiopulmonary resuscitation science that replaces the previous 5-year cyclic batch-and-queue approach process. This is the first of an annual series of International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations summary articles that will include the cardiopulmonary resuscitation science reviewed by the International Liaison Committee on Resuscitation in the previous year. The review this year includes 5 basic life support and 1 paediatric Consensuses on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Each of these includes a summary of the science and its quality based on Grading of Recommendations, Assessment, Development, and Evaluation criteria and treatment recommendations. Insights into the deliberations of the International Liaison Committee on Resuscitation task force members are provided in Values and Preferences sections. Finally, the task force members have pri-oritised and listed the top 3 knowledge gaps for each population, intervention, comparator, and outcome question. (C) 2017 European Resuscitation Council and American Heart Association, Inc. Published by Elsevier B.V. All rights reserved.Peer reviewe
A Multilaboratory Comparison of Calibration Accuracy and the Performance of External References in Analytical Ultracentrifugation
Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies
- …