2,681 research outputs found
The aquatic ecosystem, a good environment for the horizontal transfer of antimicrobial resistance and virulence-associated factors among extended spectrum beta-lactamases producing E. coli
One of the main public health problems nowadays is the increase of antimicrobial resistance,
both in the hospital environment and outside it (animal environment, food and aquatic ecosystems,
among others). It is necessary to investigate the virulence-associated factors and the ability of
horizontal gene transfer among bacteria for a better understanding of the pathogenicity and the
mechanisms of dissemination of resistant bacteria. Therefore, the objective of this work was to
detect several virulence factors genes (fimA, papC, papG III, cnf1, hlyA and aer) and to determine the
conjugative capacity in a wide collection of extended-spectrum β-lactamases-producing E. coli isolated
from different sources (human, food, farms, rivers, and wastewater treatment plants). Regarding
virulence genes, fimA, papC, and aer were distributed throughout all the studied environments, papG
III was mostly related to clinical strains and wastewater is a route of dissemination for cnf1 and hlyA.
Strains isolated from aquatic environments showed an average conjugation frequencies of 1.15 × 10−1
± 5 × 10−1
, being significantly higher than those observed in strains isolated from farms and food
(p < 0.05), with frequencies of 1.53 × 10−4 ± 2.85 × 10−4 and 9.61 × 10−4 ± 1.96 × 10−3
, respectively. The
reported data suggest the importance that the aquatic environment (especially WWTPs) acquires for
the exchange of genes and the dispersion of resistance. Therefore, specific surveillance programs of
AMR indicators in wastewaters from animal or human origin are needed, in order to apply sanitation
measures to reduce the burden of resistant bacteria arriving to risky environments as WWTPs
The aquatic ecosystem, a good environment for the horizontal transfer of antimicrobial resistance and virulence-associated factors among extended spectrum ß-lactamases producing E. coli
One of the main public health problems nowadays is the increase of antimicrobial resistance,
both in the hospital environment and outside it (animal environment, food and aquatic ecosystems,
among others). It is necessary to investigate the virulence-associated factors and the ability of
horizontal gene transfer among bacteria for a better understanding of the pathogenicity and the
mechanisms of dissemination of resistant bacteria. Therefore, the objective of this work was to
detect several virulence factors genes (fimA, papC, papG III, cnf1, hlyA and aer) and to determine the
conjugative capacity in a wide collection of extended-spectrum β-lactamases-producing E. coli isolated
from different sources (human, food, farms, rivers, and wastewater treatment plants). Regarding
virulence genes, fimA, papC, and aer were distributed throughout all the studied environments, papG
III was mostly related to clinical strains and wastewater is a route of dissemination for cnf1 and hlyA.
Strains isolated from aquatic environments showed an average conjugation frequencies of 1.15 × 10−1
± 5 × 10−1
, being significantly higher than those observed in strains isolated from farms and food
(p < 0.05), with frequencies of 1.53 × 10−4 ± 2.85 × 10−4 and 9.61 × 10−4 ± 1.96 × 10−3
, respectively. The
reported data suggest the importance that the aquatic environment (especially WWTPs) acquires for
the exchange of genes and the dispersion of resistance. Therefore, specific surveillance programs of
AMR indicators in wastewaters from animal or human origin are needed, in order to apply sanitation
measures to reduce the burden of resistant bacteria arriving to risky environments as WWTPs
Underlying SUSY in a generalized Jaynes–Cummings model
We present a general qubit-boson interaction Hamiltonian that describes the Jaynes–Cummings model and its extensions as a single Hamiltonian class. Our model includes non-linear processes for both the free qubit and boson field as well as non-linear, multi-boson excitation exchange between them. It shows an underlying algebra with supersymmetric quantum mechanics features allowing an operator based diagonalization that simplifies the calculations of observables. As a practical example, we show the evolution of the population inversion and the boson quadratures for an initial state consisting of the qubit in the ground state interacting with a coherent field for a selection of cases covering the standard Jaynes–Cummings model and some of its extensions including Stark shift, Kerr-like, intensity dependent coupling, multi-boson exchange and algebraic deformations
Evolution and study of a copycat effect in intimate partner homicides: A lesson from Spanish femicides
Objectives This paper focuses on the issue of intimate partner violence and, specifically, on the distribution of femicides over time and the existence of copycat effects. This is the subject of an ongoing debate often triggered by the social alarm following multiple intimate partner homicides (IPHs) occurring in a short span of time. The aim of this research is to study the evolution of IPHs and provide a far-reaching answer by rigorously analyzing and searching for patterns in data on femicides. Methods The study analyzes an official dataset, provided by the system VioGén of the Secretaría de Estado de Seguridad (Spanish State Secretariat for Security), including all the femicides occurred in Spain in 2007-2017. A statistical methodology to identify temporal interdepen-dencies in count time series is proposed and applied to the dataset. The same methodology can be applied to other contexts. Results There has been a decreasing trend in the number of femicides per year. No interdependen-cies among the temporal distribution of femicides are observed. Therefore, according to data, the existence of copycat effect in femicides cannot be claimed. Conclusions Around 2011 there was a clear change in the average number of femicides which has not picked up. Results allow for an informed answer to the debate on copycat effect in Spanish femicides. The planning of femicides prevention activities should not be a reaction to a perceived increase in their occurrence. As a copycat effect is not detected in the studied time period, there is no evidence supporting the need to censor media reports on femicides.The work by Torrecilla has been partially supported by Spanish Grant MTM2016-78751-P.
The research of Liberatore has been supported by the Government of Spain, grant MTM2015-65803-R, and by the Government of Madrid, grant S2013/ICE-284
Multidrug-Resistant Bacteria Isolated from Different Aquatic Environments in the North of Spain and South of France
Due to the global progress of antimicrobial resistance, the World Health Organization
(WHO) published the list of the antibiotic-resistant “priority pathogens” in order to promote research
and development of new antibiotics to the families of bacteria that cause severe and often deadly
infections. In the framework of the One Health approach, the surveillance of these pathogens in
different environments should be implemented in order to analyze their spread and the potential risk
of transmission of antibiotic resistances by food and water. Therefore, the objective of this work was
to determine the presence of high and critical priority pathogens included in the aforementioned list
in different aquatic environments in the POCTEFA area (North Spain–South France). In addition to
these pathogens, detection of colistin-resistant Enterobacteriaceae was included due its relevance
as being the antibiotic of choice to treat infections caused by multidrug resistant bacteria (MDR).
From the total of 80 analyzed samples, 100% of the wastewater treatment plants (WWTPs) and
collectors (from hospitals and slaughterhouses) and 96.4% of the rivers, carried antibiotic resistant
bacteria (ARB) against the tested antibiotics. Fifty-five (17.7%) of the isolates were identified as target
microorganisms (high and critical priority pathogens of WHO list) and 58.2% (n = 32) of them came
from WWTPs and collectors. Phenotypic and genotypic characterization showed that 96.4% were
MDR and resistance to penicillins/cephalosporins was the most widespread. The presence of bla genes,
KPC-type carbapenemases, mcr-1 and vanB genes has been confirmed. In summary, the presence
of clinically relevant MDR bacteria in the studied aquatic environments demonstrates the need to
improve surveillance and treatments of wastewaters from slaughterhouses, hospitals and WWTPs,
in order to minimize the dispersion of resistance through the effluents of these areas
Prevalence of integrons and insertion sequences in ESBL-producing E-coli isolated from different sources in Navarra, Spain
Mobile genetic elements play an important role in the dissemination of antibiotic resistant
bacteria among human and environmental sources. Therefore, the aim of this study was to determine
the occurrence and patterns of integrons and insertion sequences of extended-spectrum β-lactamase
(ESBL)-producing Escherichia coli isolated from different sources in Navarra, northern Spain. A total
of 150 isolates coming from food products, farms and feeds, aquatic environments, and humans
(healthy people and hospital inpatients), were analyzed. PCRs were applied for the study of class
1, 2, and 3 integrons (intI1, intI2, and intI3), as well as for the determination of insertion sequences
(IS26, ISEcp1, ISCR1, and IS903). Results show the wide presence and dissemination of intI1 (92%),
while intI3 was not detected. It is remarkable, the prevalence of intI2 among food isolates, as well
as the co-existence of class 1 and class 2 (8% of isolates). The majority of isolates have two or
three IS elements, with the most common being IS26 (99.4%). The genetic pattern IS26–ISEcp1
(related with the pathogen clone ST131) was present in the 22% of isolates (including human isolates).
In addition, the combination ISEcp1–IS26–IS903–ISCR1 was detected in 11 isolates being, to our
knowledge, the first study that describes this genetic complex. Due to the wide variability observed,
no relationship was determined among these mobile genetic elements and β-lactam resistance.
More investigations regarding the genetic composition of these elements are needed to understand
the role of multiple types of integrons and insertion sequences on the dissemination of antimicrobial
resistance genes among different environments
Xylotrechus arvicola (Olivier) (Coleoptera, Cerambycidae), a new impacting pest on Spanish vineyards
Research NoteInfestation caused by Xylotrechus arvicola (Olivier) (Coleoptera, Cerambycidae) is becoming a new sanitary problem in some Spanish vine-producing areas. Symptoms caused by the pest, the identification of 7 associated wood fungal species living in galleries excavated by larvae, some data about the evolution of the infestation during 8 years in the same plot and the different levels of susceptibility exhibited by three grape varieties are presented in this paper
Recent unrest (2002–2015) imaged by space geodesy at the highest risk Chilean volcanoes: Villarrica, Llaima, and Calbuco (Southern Andes)
Villarrica, Llaima, and Calbuco volcanoes are the most active and dangerous volcanoes in the Southern Andes, and we use Interferometric Synthetic Aperture Radar (InSAR) observations from multiple satellites (ERS-2, ENVISAT, ALOS, RADARSAT-2, COSMO-SkyMed, TerraSAR-X, Sentinel-1A and ALOS-2) to constrain ground deformation that spans episodes of unrest and eruption at all three volcanoes between 2002 and 2015. We find episodes of ground deformation at each volcano, which we invert using analytic elastic half space models to make some of the first geophysical inferences about the source depths of potential magma chambers. At Llaima, we interpret that the VEI 2 April 3, 2009 eruption was preceded by 6–15 cm of precursory ground uplift one month before from a source 5 km below the surface on the western side of the edifice. The VEI 2 March 3, 2015 Villarrica eruption was followed by a short lived uplift of 5 cm in the SE part of the volcano from a source depth of 6 km. The VEI 4 April 22–23, 2015 Calbuco eruption produced 12 cm of coeruptive subsidence from a source depth 8–11 km and offset 2 km S from the summit. Importantly, we do not find clear evidence that the January 1, 2008, the March 3, 2015 and April 22, 2015 eruptions at Llaima, Villarrica and Calbuco volcanoes were preceded by either transient or continuous ground uplift. There are several possible explanations for the lack of precursory deformation at each volcano – it is possible that any precursory deformation occurred only hours before the eruption (e.g., at Calbuco), pre-eruptive inflation was canceled by co-eruptive subsidence (as we inferred happened during the April 2009 Llaima eruption), the pre-eruptive deformation was too small to be detectable in areas with persistent topography correlated phase delays, pressurized source are deep, or that open-vent volcanoes like Villarrica and Llaima do not pressurize. At all three volcanoes, X and C band interferograms decorrelate in a few weeks due to vegetation, snow and ice, and have persistent atmospheric phase delays that we find cannot be reliably removed with available global weather models. The low number of SAR acquisitions therefore makes it challenging to reliably measure unaliased deformation. We recommend a multi-satellite observing strategy with short repeat periods, frequently acquired high-resolution digital elevation models, and with acquisitions during every satellite overflight that may improve the temporal resolution of measurements
Recent unrest (2002–2015) imaged by space geodesy at the highest risk Chilean volcanoes: Villarrica, Llaima, and Calbuco (Southern Andes)
Villarrica, Llaima, and Calbuco volcanoes are the most active and dangerous volcanoes in the Southern Andes, and we use Interferometric Synthetic Aperture Radar (InSAR) observations from multiple satellites (ERS-2, ENVISAT, ALOS, RADARSAT-2, COSMO-SkyMed, TerraSAR-X, Sentinel-1A and ALOS-2) to constrain ground deformation that spans episodes of unrest and eruption at all three volcanoes between 2002 and 2015. We find episodes of ground deformation at each volcano, which we invert using analytic elastic half space models to make some of the first geophysical inferences about the source depths of potential magma chambers. At Llaima, we interpret that the VEI 2 April 3, 2009 eruption was preceded by 6–15 cm of precursory ground uplift one month before from a source 5 km below the surface on the western side of the edifice. The VEI 2 March 3, 2015 Villarrica eruption was followed by a short lived uplift of 5 cm in the SE part of the volcano from a source depth of 6 km. The VEI 4 April 22–23, 2015 Calbuco eruption produced 12 cm of coeruptive subsidence from a source depth 8–11 km and offset 2 km S from the summit. Importantly, we do not find clear evidence that the January 1, 2008, the March 3, 2015 and April 22, 2015 eruptions at Llaima, Villarrica and Calbuco volcanoes were preceded by either transient or continuous ground uplift. There are several possible explanations for the lack of precursory deformation at each volcano – it is possible that any precursory deformation occurred only hours before the eruption (e.g., at Calbuco), pre-eruptive inflation was canceled by co-eruptive subsidence (as we inferred happened during the April 2009 Llaima eruption), the pre-eruptive deformation was too small to be detectable in areas with persistent topography correlated phase delays, pressurized source are deep, or that open-vent volcanoes like Villarrica and Llaima do not pressurize. At all three volcanoes, X and C band interferograms decorrelate in a few weeks due to vegetation, snow and ice, and have persistent atmospheric phase delays that we find cannot be reliably removed with available global weather models. The low number of SAR acquisitions therefore makes it challenging to reliably measure unaliased deformation. We recommend a multi-satellite observing strategy with short repeat periods, frequently acquired high-resolution digital elevation models, and with acquisitions during every satellite overflight that may improve the temporal resolution of measurements
Transverse ratchet effect and superconducting vortices: simulation and experiment
A transverse ratchet effect has been measured in magnetic/ superconducting hybrid films fabricated by electron beam lithography and magnetron sputtering techniques. The samples are Nb films grown on top of an array of Ni nanotriangles. Injecting an ac current parallel to the triangle reflection symmetry axis yields an output dc voltage perpendicular to the current, due to a net motion of flux vortices in the superconductor. The effect is reproduced by numerical simulations of vortices as Langevin particles with realistic parameters. Simulations provide an intuitive picture of the ratchet mechanism, revealing the fundamental role played by the random intrinsic pinning of the superconductor
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