148 research outputs found
Real-time PCR optimization to identify Mycobacterium tuberculosis complex strains in clinical samples.
Resumen del artículo publicado en FEBS Journal,http://dx.doi.org/10.1111/febs.12919During recent years several molecular techniques have become available for Mycobacterium tuberculosis complex (MTC) detection,both for clinical samples and for isolates. One of the techniques more widely used is real time PCR in combination with nucleic acid amplification protocols. There are numerous studies based on PCR for the diagnosis of tuberculosis although the different protocols and primers used in the laboratory, together with the variability in the diagnostic performance of the methods tested, require that a comparative study be performed. Furthermore,the fact that the detection from clinical samples requires using highly sensitive targets suggests that this type of study should include multicopy targets to compare their efficiency with respect to the single copy. Our aim was to identify the members of the MTC using real-time PCR assays based on SYBR Green,among a large panel of isolated bacterial strains and clinical samples.We chose three targets (IS6110, senx3-regx3 and cfp32) and the optimal values for each PCR assay were empirically defined by testing in triplicate different concentrations of MgCl2 and primer sets and different annealing temperatures. These conditions were determined based on the specific amplification reactions that
showed a lower Ct value, higher fluorescence and absence of non-specific PCR products. The analytical sensitivity was evaluated by ten-fold serial dilutions of DNA from MTC and the specificity was tested by 62 different microorganisms, including bacteria related with the MTC. The diagnostic yield was evaluated in 66 specimens from patients with suspected tuberculosis;30 had tuberculosis and 36 (control group) had different diseases.Under the conditions that resulted in optimization, standard
curves showed that senx3-regx3 assay was the most efficient, followed by IS6110 and cfp32. However, the detection of bacterial DNA was faster with the repetitive element IS6110, with Ct values of up to 3 and 9 cycles of difference with respect to senx3-regx3 and cfp32. The analytical specificity, done only with the senx3-regx3 and IS6110 targets, was in the order of 100 and 93.5%, since IS6110 amplified various non-tuberculous micobacteria.For all the clinical samples studied, the sensitivity of both assays was identical (93.3%) but the specificity of senx3-regx3(100%) was higher than that of IS6110 (94.7%). In conclusion,real time PCR assay-SYBR Green based on the targets senx3-regx3 is highly reproducible and more sensitive and specific than
the assays based on IS6110 or cfp32. The protocol developed in this study provides an appropriate and rapid tool to identify the strains of MTC in different clinical isolates and specimens.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Localization of Leaks in Water Distribution Networks using Flow Readings
This paper presents a novel approach to localize single and sequential leaks based on the lumped model of a water distribution network (WDN). The principal features of such a model are: a new friction term expressed as a power-law and a suitable representation expressed only in terms of the flow rate. From the response of this model and flow rate measurements at junctions of the pipelines composing the WDN, a set of residuals1 is proposed for each pipeline. The residuals closest to zero will indicate the leak positions in the faulty pipelines. We present some simulation tests based on data from PipelineStudio® from Energy Solutions to illustrate the suitability of our method
Rules, Standards, and the Internal Point of View
Large scale structure and cosmolog
Linking land cover changes in the subalpine and montane belts to changes in a torrential river.
Channel cbanges are the consequence of cbanges in sediment yield from the slopes and in the connectivity between slopes and channels
bccause of distinct land use and climate inJpacts. In Ibis study, we investigated the characteristics and evolution of a short reach in the
headwater of the !juez River, central-soutbem Pyrenees. Assessment of a series of sedimentar)' and geomorphic structures confirtned major
cbanges to the valley boUom, mainly related to changes in the intensity of human activity. 'The oldest sedimentar)' structure is a terrace leve!
located 3 10 4 m above the current alluvial plain. General deforestation, overgrazing and recwring tires in the montane belt ( 1100-1600 m a.sJ.)
have led 10 increased soil erosioo and connectivity, and to tbe triggering of debris llows thal have been deposited on the fluvial tmace. Woody
fragments from within the debris llows were dated using acceleraror mass spectrOmetry '"e radiocaroon tcchniques (AMS), yielding ages
between 1 00 and 115 cal years BP, whicb coincides with tbe period of maximum deforestalion and human density in the Pyrenees.
Depopulation and fannland abaodonment since tbe beginning of tbe 2001 oenrury has resulled in generalliJcod natural and artificial reforestation,
a shrinkage of the eroded arcas aod a decline in connectivi¡y bdween slopes and the channel. 1be rnost impor1an1 consequence has been cbannel
incision and oarrowing, and the development of a sedimed annour !ayer. Active sedimenl b8llSpOI1 is continui.Qg, although there has been a
decrease in sed.iment yield from the slopes. Copyright O 2014 John Wiley & Soos, Ltd
J-PLUS: analysis of the intracluster light in the Coma cluster
The intracluster light (ICL) is a luminous component of galaxy clusters
composed of stars that are gravitationally bound to the cluster potential but
do not belong to the individual galaxies. Previous studies of the ICL have
shown that its formation and evolution are intimately linked to the
evolutionary stage of the cluster. Thus, the analysis of the ICL in the Coma
cluster will give insights into the main processes driving the dynamics in this
highly complex system. Using a recently developed technique, we measure the ICL
fraction in Coma at several wavelengths, using the J-PLUS unique filter system.
The combination of narrow- and broadband filters provides valuable information
on the dynamical state of the cluster, the ICL stellar types, and the
morphology of the diffuse light. We use the Chebyshev-Fourier Intracluster
Light Estimator (CICLE) to disentangle the ICL from the light of the galaxies,
and to robustly measure the ICL fraction in seven J-PLUS filters. We obtain the
ICL fraction distribution of the Coma cluster at different optical wavelengths,
which varies from , showing the highest values in the narrowband
filters J0395, J0410, and J0430. This ICL fraction excess is distinctive
pattern recently observed in dynamically active clusters (mergers), indicating
a higher amount of bluer stars in the ICL compared to the cluster galaxies.
Both the high ICL fractions and the excess in the bluer filters are indicative
of a merging state. The presence of younger/lower-metallicity stars the ICL
suggests that the main mechanism of ICL formation for the Coma cluster is the
stripping of the stars in the outskirts of infalling galaxies and, possibly,
the disruption of dwarf galaxies during past/ongoing mergers.Comment: 10 pages, 3 figures, 1 table. Accepted for publication in A&
Propuesta estratégica de mejora en la implementación de los estándares mínimos del sistema de gestión de seguridad y salud en el trabajo, para la organización industrial de gases S.A.S, en el primero semestre del 2020.
Hoy las empresas deben brindar espacios propicios y condiciones de trabajo dignas, que
mejoren la calidad de vida de todos los empleados; la seguridad y salud en el trabajo es vital para
un correcto funcionamiento de una organización, ya que permite mejorar las experiencias de
bienestar, social, mental y físico de los trabajadores, todo ello enfocado a prevenir, identificar y
controlar las enfermedades laborales y accidentes de trabajo.
Teniendo en cuenta que la mayoría de los trabajadores pasan largas jornadas en sus
puestos de trabajo, las organizaciones deben encaminar acciones estratégicas que fortalezcan la
salud física, mental y emocional de cada trabajador. Los accidentes o enfermedades laborales
acarrean grandes costo y traen consigo impactos negativos a las partes interesadas pertinentes de
la organización (familias, colaboradores y directivos).Today companies must provide auspicious spaces and decent working conditions, which
improve the quality of life of all employees; occupational safety and health is vital for
a proper functioning of an organization, since it allows to improve the experiences of
welfare, social, mental and physical workers, all focused on preventing, identifying and
control occupational diseases and accidents.
Bearing in mind that most workers spend long hours in their
jobs, organizations must direct strategic actions that strengthen the
Physical, mental and emotional health of each worker. Accidents or occupational diseases
they carry large costs and bring negative impacts to the relevant stakeholders of
the organization (families, collaborators and managers)
On the buildup of massive early-type galaxies at z<~1. I- Reconciling their hierarchical assembly with mass-downsizing
Several studies have tried to ascertain whether or not the increase in
abundance of the early-type galaxies (E-S0a's) with time is mainly due to major
mergers, reaching opposite conclusions. We have tested it directly through
semi-analytical modelling, by studying how the massive early-type galaxies with
log(M_*/Msun)>11 at z~0 (mETGs) would have evolved backwards-in-time, under the
hypothesis that each major merger gives place to an early-type galaxy. The
study was carried out just considering the major mergers strictly reported by
observations at each redshift, and assuming that gas-rich major mergers
experience transitory phases of dust-reddened, star-forming galaxies (DSFs).
The model is able to reproduce the observed evolution of the galaxy LFs at
z<~1, simultaneously for different rest-frame bands (B, I, and K) and for
different selection criteria on color and morphology. It also provides a
framework in which apparently-contradictory results on the recent evolution of
the luminosity function (LF) of massive, red galaxies can be reconciled, just
considering that observational samples of red galaxies can be significantly
contaminated by DSFs. The model proves that it is feasible to build up ~50-60%
of the present-day mETG population at z<~1 and to reproduce the observational
excess by a factor of ~4-5 of late-type galaxies at 0.8<z<1 through the
coordinated action of wet, mixed, and dry major mergers, fulfilling global
trends that are in general agreement with mass-downsizing. The bulk of this
assembly takes place during ~1 Gyr elapsed at 0.8<z<1. The model suggests that
major mergers have been the main driver for the observational migration of mass
from the massive-end of the blue galaxy cloud to that of the red sequence in
the last ~8 Gyr.(Abridged)Comment: Accepted for publication in Astronomy & Astrophysics; 21 pages, 8
figures. Minor corrections included, shortened title. Results and conclusions
unchange
Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers
We present new improved constraints on the Hubble parameter H(z) in the
redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic
evolution of early-type galaxies as a function of redshift. We extract a large
sample of early-type galaxies (\sim11000) from several spectroscopic surveys,
spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We
select the most massive, red elliptical galaxies, passively evolving and
without signature of ongoing star formation. Those galaxies can be used as
standard cosmic chronometers, as firstly proposed by Jimenez & Loeb (2002),
whose differential age evolution as a function of cosmic time directly probes
H(z). We analyze the 4000 {\AA} break (D4000) as a function of redshift, use
stellar population synthesis models to theoretically calibrate the dependence
of the differential age evolution on the differential D4000, and estimate the
Hubble parameter taking into account both statistical and systematical errors.
We provide 8 new measurements of H(z) (see Tab. 4), and determine its change in
H(z) to a precision of 5-12% mapping homogeneously the redshift range up to z
\sim 1.1; for the first time, we place a constraint on H(z) at z \neq 0 with a
precision comparable with the one achieved for the Hubble constant (about 5-6%
at z \sim 0.2), and covered a redshift range (0.5 < z < 0.8) which is crucial
to distinguish many different quintessence cosmologies. These measurements have
been tested to best match a \Lambda CDM model, clearly providing a
statistically robust indication that the Universe is undergoing an accelerated
expansion. This method shows the potentiality to open a new avenue in constrain
a variety of alternative cosmologies, especially when future surveys (e.g.
Euclid) will open the possibility to extend it up to z \sim 2.Comment: 34 pages, 15 figures, 6 tables, published in JCAP. It is a companion
to Moresco et al. (2012b, http://arxiv.org/abs/1201.6658) and Jimenez et al.
(2012, http://arxiv.org/abs/1201.3608). The H(z) data can be downloaded at
http://www.physics-astronomy.unibo.it/en/research/areas/astrophysics/cosmology-with-cosmic-chronometer
J-PLUS: Detecting and studying extragalactic globular clusters -- the case of NGC 1023
Extragalactic globular clusters (GCs) are key objects for studying the
formation and evolution of galaxies. The arrival of wide-field surveys such as
the Javalambre Photometric Local Universe Survey (J-PLUS) offers new
possibilities for the study of GCs. Nevertheless, GCs are not detected a priori
by the data reduction pipeline of J-PLUS and, due to its pixel scale, the
standard techniques of GCs detection are challenged. To fill this gap, we
develop a semi-automatic pipeline to detect GCs in J-PLUS that can also be
adapted to similar surveys. As a case study, we use data from the S0 galaxy NGC
1023 and we also study the stellar population content of GC candidates in the
galaxy. To detect GCs, our methodology is based on Source Extractor and does
not require a previous filtering or modelling of the host galaxy. We study
colors and perform spectral energy distribution (SED) analysis on our final GC
candidate catalog to obtain stellar population parameters. In NGC 1023,
GCFinder identifies 523 GC candidates. We observe evidence of color bimodality
in a few broad-band colors but not on narrow-band colors. The SED analysis
reveals a clear metallicity bimodality and we observe that narrow-band filters
are very useful to constrain metallicities. We also identified a broad
age-metallicity relation as well as a wide metallicity distribution that are
evidence that NGC 1023 experienced accretion events in the past. It is the
first time this kind of study is performed with J-PLUS data. By detecting GC
candidates in wide-field images without modeling the light of the galaxy,
GCFinder becomes considerably faster, at a marginal loss of centrally-located
GC candidates of about 7 percent. As GCFinder is entirely based on Source
Extractor, it could be easily incorporated into automated software handling
wide-field surveys.Comment: 21 pages, 19 figures, submitted to A&
Combination of Tocilizumab and Steroids to Improve Mortality in Patients with Severe COVID-19 Infection : A Spanish, Multicenter, Cohort Study
We aimed to determine the impact of tocilizumab use on severe COVID-19 (coronavirus disease 19) pneumonia mortality. We performed a multicentre retrospective cohort study in 18 tertiary hospitals in Spain from March to April 2020. Consecutive patients admitted with severe COVID-19 treated with tocilizumab were compared to patients not treated with tocilizumab, adjusting by inverse probability of the treatment weights (IPTW). Tocilizumab's effect in patients receiving steroids during the 48 h following inclusion was analysed. During the study period, 506 patients with severe COVID-19 fulfilled the inclusion criteria. Among them, 268 were treated with tocilizumab and 238 patients were not. Median time to tocilizumab treatment from onset of symptoms was 11 days [interquartile range (IQR) 8-14]. Global mortality was 23.7%. Mortality was lower in patients treated with tocilizumab than in controls: 16.8% versus 31.5%, hazard ratio (HR) 0.514 [95% confidence interval (95% CI) 0.355-0.744], p < 0.001; weighted HR 0.741 (95% CI 0.619-0.887), p = 0.001. Tocilizumab treatment reduced mortality by 14.7% relative to no tocilizumab treatment [relative risk reduction (RRR) 46.7%]. We calculated a number necessary to treat of 7. Among patients treated with steroids, mortality was lower in those treated with tocilizumab than in those treated with steroids alone [10.9% versus 40.2%, HR 0.511 (95% CI 0.352-0.741), p = 0.036; weighted HR 0.6 (95% CI 0.449-0.804), p < 0.001] (interaction p = 0.094). These results show that survival of patients with severe COVID-19 is higher in those treated with tocilizumab than in those not treated and that tocilizumab's effect adds to that of steroids administered to non-intubated patients with COVID-19 during the first 48 h of presenting with respiratory failure despite oxygen therapy. Randomised controlled studies are needed to confirm these results. European Union electronic Register of Post-Authorization Studies (EU PAS Register) identifier, EUPAS34415 The online version of this article (10.1007/s40121-020-00373-8) contains supplementary material, which is available to authorized users
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