39 research outputs found
Unraveling the ecological processes modulating the population structure of Escherichia coli in a highly polluted urban stream network
Escherichia coli dynamics in urban watersheds are affected by a complex balance among external inputs, niche modulation and genetic variability. To explore the ecological processes influencing E. coli spatial patterns, we analyzed its abundance and phylogenetic structure in water samples from a stream network with heterogeneous urban infrastructure and environmental conditions. Our results showed that environmental and infrastructure variables, such as macrophyte coverage, DIN and sewerage density, mostly explained E. coli abundance. Moreover, main generalist phylogroups A and B1 were found in high proportion, which, together with an observed negative relationship between E. coli abundance and phylogroup diversity, suggests that their dominance might be due to competitive exclusion. Lower frequency phylogroups were associated with sites of higher ecological disturbance, mainly involving simplified habitats, higher drainage infrastructure and septic tank density. In addition to the strong negative relationship between phylogroup diversity and dominance, the occurrence of these phylogroups would be associated with increased facilitated dispersal. Nutrients also contributed to explaining phylogroup distribution. Our study proposes the differential contribution of distinct ecological processes to the patterns of E. coli in an urban watershed, which is useful for the monitoring and management of fecal pollution.Fil: Saraceno, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Gómez Lugo, Sebastian. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Ortiz, Nicolás. Provincia de Mendoza. Ministerio de Infraestructura y Vivienda. Secretaria de Obras Publicas. Instituto Nacional del Agua; ArgentinaFil: Gómez, Bárbara M.. Provincia de Mendoza. Ministerio de Infraestructura y Vivienda. Secretaria de Obras Publicas. Instituto Nacional del Agua; ArgentinaFil: Sabio y García, Carmen Alejandra. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Frankel, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Graziano, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin
Physical structure of the envelopes of intermediate-mass protostars
Context: Intermediate mass protostars provide a bridge between low- and
high-mass protostars. Furthermore, they are an important component of the UV
interstellar radiation field. Despite their relevance, little is known about
their formation process. Aims: We present a systematic study of the physical
structure of five intermediate mass, candidate Class 0 protostars. Our two
goals are to shed light on the first phase of intermediate mass star formation
and to compare these protostars with low- and high-mass sources. Methods: We
derived the dust and gas temperature and density profiles of the sample. We
analysed all existing continuum data on each source and modelled the resulting
SED with the 1D radiative transfer code DUSTY. The gas temperature was then
predicted by means of a modified version of the code CHT96. Results: We found
that the density profiles of five out of six studied intermediate mass
envelopes are consistent with the predictions of the "inside-out" collapse
theory.We compared several physical parameters, like the power law index of the
density profile, the size, the mass, the average density, the density at 1000
AU and the density at 10 K of the envelopes of low-, intermediate, and
high-mass protostars. When considering these various physical parameters, the
transition between the three groups appears smooth, suggesting that the
formation processes and triggers do not substantially differ
On the nature of outflows in intermediate-mass protostars: a case study of IRAS 20050+2720
Context. This is the third of a series of papers devoted to study in detail
and with high-angular resolution intermediate-mass molecular outflows and their
powering sources. Aims. The aim of this paper is to study the intermediate-mass
YSO IRAS 20050+2720 and its molecular outflow, and put the results of this and
the previous studied sources in the context of intermediate-mass star
formation. Methods. We carried out VLA observations of the 7 mm continuum
emission, and OVRO observations of the 2.7 mm continuum emission, CO(1-0),
C18O(1-0), and HC3N(12-11) to map the core towards IRAS 20050+2720. The
high-angular resolution of the observations allowed us to derive the properties
of the dust emission, the molecular outflow, and the dense protostellar
envelope. By adding this source to the sample of intermediate-mass protostars
with outflows, we compare their properties and evolution with those of lower
mass counterparts. Results. The 2.7mm continuum emission has been resolved into
three sources, labeled OVRO 1, OVRO 2, and OVRO 3. Two of them, OVRO 1 and OVRO
2, have also been detected at 7 mm. OVRO 3, which is located close to the C18O
emission peak, could be associated with IRAS 20050+2720. The mass of the
sources, estimated from the dust continuum emission, is 6.5 Msun for OVRO 1,
1.8 Msun for OVRO 2, and 1.3 Msun for OVRO 3. The CO(1-0) emission traces two
bipolar outflows within the OVRO field of view, a roughly east-west bipolar
outflow, labeled A, driven by the intermediate-mass source OVRO 1, and a
northeast-southwest bipolar outflow, labeled B, probably powered by a YSO
engulfed in the circumstellar envelope surrounding OVRO 1.Comment: 13 pages, 8 figures, 5 tables. Accepted for publication by A&
A Spitzer Space Telescope far-infrared spectral atlas of compact sources in the Magellanic Clouds. I. The Large Magellanic Cloud
[abridged] We present 52-93 micron spectra obtained with Spitzer in the
MIPS-SED mode, of a representative sample of luminous compact far-IR sources in
the LMC. These include carbon stars, OH/IR AGB stars, post-AGB objects and PNe,
RCrB-type star HV2671, OH/IR red supergiants WOHG064 and IRAS05280-6910, B[e]
stars IRAS04530-6916, R66 and R126, Wolf-Rayet star Brey3a, Luminous Blue
Variable R71, supernova remnant N49, a large number of young stellar objects,
compact HII regions and molecular cores, and a background galaxy (z~0.175). We
use the spectra to constrain the presence and temperature of cold dust and the
excitation conditions and shocks within the neutral and ionized gas, in the
circumstellar environments and interfaces with the surrounding ISM. Evolved
stars, including LBV R71, lack cold dust except in some cases where we argue
that this is swept-up ISM. This leads to an estimate of the duration of the
prolific dust-producing phase ("superwind") of several thousand years for both
RSGs and massive AGB stars, with a similar fractional mass loss experienced
despite the different masses. We tentatively detect line emission from neutral
oxygen in the extreme RSG WOHG064, with implications for the wind driving. In
N49, the shock between the supernova ejecta and ISM is revealed by its strong
[OI] 63-micron emission and possibly water vapour; we estimate that 0.2 Msun of
ISM dust was swept up. Some of the compact HII regions display pronounced
[OIII] 88-micron emission. The efficiency of photo-electric heating in the
interfaces of ionized gas and molecular clouds is estimated at 0.1-0.3%. We
confirm earlier indications of a low nitrogen content in the LMC. Evidence for
solid state emission features is found in both young and evolved object; some
of the YSOs are found to contain crystalline water ice.Comment: Accepted for publication in The Astronomical Journal. This paper
accompanies the Summer 2009 SAGE-Spec release of 48 MIPS-SED spectra, but
uses improved spectrum extraction. (Fig. 2 reduced resolution because of
arXiv limit.
Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members
Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic.
Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine.
Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis.
Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
SAM-driven variability of the southwestern Atlantic shelf sea circulation
The objective of the present study is to analyze the interannual variability of the Southwestern Atlantic Continental Shelf (SWACS) circulation and its thermohaline structure. To accomplish it we employed the global ocean reanalysis ORAP5.0, which spans the 35-years period 1979–2013. ORAP5.0 satisfactorily reproduces the most distinctive features of the SWACS circulation and its variability on different timescales, including the interannual scale. The first mode of a joint empirical orthogonal function (EOF) analysis of sea surface temperature (SST), sea surface salinity (SSS), and vertically averaged horizontal velocities is significantly correlated with the first mode of interannual variability of the atmosphere in the Southern Hemisphere, the Southern Annular Mode (SAM). Remarkably, the shelf sea response has been found to be statistically significant not only in the Patagonian Shelf (south of 40 °S), as discussed in the literature, but also in the Northern Shelf (north of 40°S). During the active phases of the leading mode, current anomalies develop as a result of the sea surface height adjustment to Ekman transport at the coastline induced by alongshore wind anomalies. Modification of the advection terms in the salinity and heat budgets due to changes in the circulation and heat surface fluxes generate SST and SSS anomalies along the SWACS. It is suggested that these anomalies drive changes in the mixed layer depth and that these changes can modulate the interannual variability of the chlorophyll-a concentration during austral spring in the frontal zones.Fil: Bodnariuk, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Simionato, Claudia Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Saraceno, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; Argentin
Trends in sea surface temperature and air–sea heat fluxes over the South Atlantic Ocean
The understanding of latent and sensible heat fluxes (LHF and SHF, respectively) is essential to improve our knowledge on how the atmosphere and oceans interact. In this work we identified trends of LHF and SHF in the South Atlantic (SA) Ocean from 1982 to 2015 and evaluated the potential drivers that contribute to those trends. Based on the Objectively Analyzed air–sea Fluxes (OAFlux) dataset, the European Centre for Medium Range Weather Forecasts (ERA-Interim) and the Optimum Interpolation sea surface temperature (SST) Analysis Version 2 we analyze trends and interannual variability of seasonal heat fluxes and variables influencing them. Heat fluxes trends in the SA have a strong regional and seasonal dependence. The highest increase of heat fluxes is found over the region delimited to the West and to the South by the Brazil Current Front (referred to as the Extended Brazil Current Region; ExtBCR).The humidity (temperature) differences and U10m in the ExtBCR only contributed to explain trends of LHF (SHF) in winter. Other mechanisms should be considered to explain the LHF and SHF trend observed in summer and in the rest of the SA. The close correspondence found between the trends in temperature and humidity differences and the trend in SST, indicates that the largest driver of trends in heat fluxes over the ExtBCR are the SST trends. We argue that the expansion and intensification of the South Atlantic Subtropical High causes an increase of wind speed which intensifies the western boundary current, leading to an increase of SST and therefore an intensification of heat fluxes.Fil: Leyba, Inés Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Centre National de la Recherche Scientifique; Francia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; ArgentinaFil: Solman, Silvina Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Centre National de la Recherche Scientifique; FranciaFil: Saraceno, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Centre National de la Recherche Scientifique; Franci