3,229 research outputs found
A Bayesian model for anchovy (Engraulis encrasicolus): the combined forcing of man and environment
Fishery collapses frequently result from combined
pressures of the environment and man, which are
difficult to discern because of the complexities
involved and our limited knowledge. Models to resolve
this complexity often become too sophisticated,
with too many assumptions and, consequently, with
little capacity to predict beyond calibration data. In
this paper we implement a different procedure where
the model is kept simple and uncertainty accounts for
the equation imperfectness to reproduce ecological
complexity. Human and environmental forcing on an
anchovy (Engraulis encrasicolus) stock are simulated
with only six parameters plus their error terms, and
the uncertainty is computed with Bayesian methods.
The simple structure is able to reproduce the major
dynamical features of this species in the Gulf of
Ca´diz, including data on life stages and age structure
that had no contact with the model. This is a distinct
performance for a frugal approach working on a
mid-trophic species and a positive instance where
parsimony can simulate the interaction of man,
fish and the environment, provided uncertainty is
accounted for in the process.Publicado
Constraining Explosion Type of Young Supernova Remnants Using 24 Micron Emission Morphology
Determination of the explosion type of supernova remnants (SNRs) can be
challenging, as SNRs are hundreds to thousands of years old and supernovae
(SNe) are classified based on spectral properties days after explosion.
Previous studies of thermal X-ray emission from Milky Way and Large Magellanic
Cloud (LMC) SNRs have shown that Type Ia and core-collapse (CC) SNRs have
statistically different symmetries, and thus these sources can be typed based
on their X-ray morphologies. In this paper, we extend the same technique, a
multipole expansion technique using power ratios, to infrared (IR) images of
SNRs to test whether they can be typed using the symmetry of their warm dust
emission as well. We analyzed archival Spitzer Space Telescope Multiband
Imaging Photometer (MIPS) 24 micron observations of the previously used X-ray
sample, and we find that the two classes of SNRs separate according to their IR
morphologies. The Type Ia SNRs are statistically more circular and mirror
symmetric than the CC SNRs, likely due to the different circumstellar
environments and explosion geometries of the progenitors. Broadly, our work
indicates that the IR emission retains information of the explosive origins of
the SNR and offers a new method to type SNRs based on IR morphology.Comment: 6 pages, 4 figures; accepted by ApJ
The atypical chemokine receptor Ackr2 constrains NK cell migratory activity and promotes metastasis
Chemokines have been shown to be essential players in a range of cancer contexts. In this study, we demonstrate that mice deficient in the atypical chemokine receptor Ackr2 display impaired development of metastasis in vivo in both cell line and spontaneous models. Further analysis reveals that this relates to increased expression of the chemokine receptor CCR2, specifically by KLRG1+ NK cells from the Ackr2−/− mice. This leads to increased recruitment of KLRG1+ NK cells to CCL2-expressing tumors and enhanced tumor killing. Together, these data indicate that Ackr2 limits the expression of CCR2 on NK cells and restricts their tumoricidal activity. Our data have important implications for our understanding of the roles for chemokines in the metastatic process and highlight Ackr2 and CCR2 as potentially manipulable therapeutic targets in metastasis
Expanding the recombinant protein quality in Lactococcus lactis
Background: Escherichia coli has been a main host for the production of recombinant proteins of biomedical interest, but conformational stress responses impose severe bottlenecks that impair the production of soluble, proteolytically stable versions of many protein species. In this context, emerging Generally Recognized As Safe (GRAS) bacterial hosts provide alternatives as cell factories for recombinant protein production, in which limitations associated to the use of Gram-negative microorganisms might result minimized. Among them, Lactic Acid Bacteria and specially Lactococcus lactis are Gram-positive GRAS organisms in which recombinant protein solubility is generically higher and downstream facilitated, when compared to E. coli. However, deep analyses of recombinant protein quality in this system are still required to completely evaluate its performance and potential for improvement. - Results : we have explored here the conformational quality (through specific fluorescence emission) and solubility of an aggregation-prone GFP variant (VP1GFP) produced in L. lactis. In this context, our results show that parameters such as production time, culture conditions and growth temperature have a dramatic impact not only on protein yield, but also on protein solubility and conformational quality, that are particularly favored under fermentative metabolism. - Conclusions: metabolic regime and cultivation temperature greatly influence solubility and conformational quality of an aggregation-prone protein in L. lactis. Specifically, the present study proves that anaerobic growth is the optimal condition for recombinant protein production purposes. Besides, growth temperature plays an important role regulating both protein solubility and conformational quality. Additionally, our results also prove the great versatility for the manipulation of this bacterial system regarding the improvement of functionality, yield and quality of recombinant proteins in this species. These findings not only confirm L. lactis as an excellent producer of recombinant proteins but also reveal room for significant improvement by the exploitation of external protein quality modulators
The Burst Cluster: Dark Matter in a Cluster Merger Associated with the Short Gamma Ray Burst, GRB 050509B
We have identified a merging galaxy cluster with evidence of two distinct
sub-clusters. The X-ray and optical data suggest that the subclusters are
moving away from each other after closest approach. This cluster merger was
discovered from observations of the well localized short-duration gamma-ray
burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope (BAT) source position
is coincident with a cluster of galaxies ZwCl 1234.0+02916. The subsequent
Swift/X-Ray Telescope (XRT) localization of the X-ray afterglow found the GRB
coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the
cluster. Deep multi-epoch optical images were obtained to constrain the
evolution of the GRB afterglow, including a 27480s exposure in the F814W band
with Hubble Space Telescope Advanced Camera for Surveys (ACS), among the
deepest imaging ever obtained towards a known galaxy cluster in a single
passband. We perform a weak gravitational lensing analysis, including mapping
the total mass distribution of the merger system. Combined with Chandra X-ray
Observatory and Swift/XRT observations, we investigate the dynamical state of
the merger to probe the nature of the dark matter component. Our weak
gravitational lensing measurements reveal a separation of the X-ray centroid of
the western subcluster from the center of the mass and galaxy light
distributions, similar to that of the famous "Bullet cluster". We conclude that
the "Burst cluster" is another candidate merger system for determining the
nature of dark matter and for studying the environment of short GRBs. We
discuss connections between the cluster dynamical state and/or matter
composition and compact object mergers, the leading model for the origin of
short GRBs. Finally, we present results from a weak lensing survey based on
archival Very Large Telescope (VLT) images in the areas of 5 other short GRBs.Comment: 17 pages, 7 figures, accepted by Ap
iFADO project: contribution to the determination of the Good Environmental Status in the Atlantic Area through modeling and in situ monitoring approaches
The project iFADO ( innovation in the Framework of the Atlantic Deep Ocean ) aims to combine conventional monitoring programs (with special focus on novel semi-automatic techniques that can be applied for in situ biological monitoring) with emerging technologies (such as gliders, satellite imagery, etc.) and modeling approaches to assist the implementation of the Marine Strategy Framework Directive (MSFD), providing tools for the optimization of observing strategies for better evaluation and forecasting of the Good Environmental Status (GES). Within this framework, the multidisciplinary iFADO cruise (within the RADPROF time series program, Instituto Español de Oceanografía) was carried out with transnational collaboration on summer 2020 along a standard coastal-oceanic transect off NW Iberian Peninsula, including physical, biogeochemical and biological measurements. Additionally, an effort is being made in the implementation and validation of existing and new biogeochemical models in the Atlantic margin, focusing on key variables for the implementation of MSFD Descriptors. The combination of iFADO models and in situ monitoring approaches not only might contribute data and potential indicators for MSFD Descriptors 1, 2, 3, 4, 5, 6, 7 and 10, from coastal to open-ocean environments, but they are essential tools to detect, model and predict temporal changes in marine ecosystems in the study area
Winter distributions of Dinophysis populations: do they help to predict the onset of the bloom?
Blooms of diarrhetic shellfish toxin (DST) producers of the genus Dinophysis (D. acuminata, D. acuta) pose the main threat to the sustainable exploitation of cultivated mussels and other bivalves on the Atlantic coasts of Europe. Dinophysis species do not rely on cysts as a seeding strategy. Detection and evaluation of holoplanktonic populations surviving after bloom decline may be the key to predict the initiation of next year’s bloom. Three cruises were carried out on the NW Iberian shelf in February 2013 (DINVER 2013), January 2006 (DINVER 2006) and May-June 1993 (MORENA 93) to explore winter (D. acuminata) and pre-bloom (D. acuta) distributions of harmful microalgal species. Sampling protocols were adapted to be able to detect extremely low densities (1-5 cells l-1) of Dinophysis species. Potential inoculum populations in retention areas, as previously described for other species in upwelling regions, were not found on these cruises. Here we explore retrospectively data from these cruises, identify hydrodynamic patterns, and accompanying microplanktonic communities, in an attempt to untangle a crucial question in Dinophysis population dynamics: how to predict the initiation of the Dinophysis growth season.ISSHAEn prens
Eficácia da Suplementação de citrulina para diminuir o risco de hipertensão pulmonar após cirurgia de cardiopatia congênita: Uma experiência local
Pulmonary hypertension (PH) is a major cause of morbi-mortality among patients with congenital heart disease (CHD) and also a potentially severe complication after surgical repair. Oral citrulline, a precursor to NO synthesis, is safe and efficacious for decreasing the risk of postoperative PH. Objective: The aim of the present study was to investigate in pediatric patients the changes of plasma citrulline, arginine, homocysteine and nitric oxide (NO) metabolites and pulmonary artery pressures (PAP) pre-post cardiac surgery in order to describe our population status with regard to the risk of pulmonary hypertension and look for potential biomarkers for early detection and treatment. Main results/Discussion: 16 Argentine pediatric patients with CHD undergoing cardiopulmonary bypass were randomized in two groups: (A) with and (B) without perioperative citrulline supplementation. We found that plasma citrulline median levels before surgery were lower in both groups respect to referential values, probably due to the poor nutritional status of our patients; only group A surpassed post-surgery the minimum recommended level to avoid PH. Furthermore, none of the patients in group A showed mean PAP higher than 20 mmHg, whereas in group B, 67% of the measurements were ≥ than the reference level. Conclusions: We reaffirm that citrulline supplementation it is effective in reducing postoperative pulmonary hypertension and biomarkers could evidence patient status as a translational medicine application.La hipertensión pulmonar (HP) es una causa importante de morbimortalidad entre pacientes con cardiopatía congénita (CHD) y también una complicación potencialmente grave después de la reparación quirúrgica. La citrulina oral, precursora de la síntesis de óxido nítrico, es segura y eficaz para disminuir el riesgo postoperatorio de HP. Objetivo: El presente estudio tuvo como objetivo investigar en pacientes pediátricos los cambios plasmáticos de los metabolitos citrulina, arginina, homocisteína y óxido nítrico y la presión arterial pulmonar (PAP) antes y después de la cirugía cardíaca para describir el estado de nuestra población con respecto al riesgo de HP y buscar posibles biomarcadores para su detección y tratamiento temprano. Resultados principales / Discusión: 16 pacientes pediátricos argentinos con CHD sometidos a bypass cardiopulmonar fueron aleatorizados en dos grupos: (A) con y (B) sin suplementación perioperatoria de citrulina. Encontramos que los niveles medios de citrulina en plasma antes de la cirugía fueron más bajos en ambos grupos con respecto a los valores referenciales, probablemente debido a un estado nutricional deficiente de nuestros pacientes; solo el grupo A superó el nivel mínimo recomendado para evitar la HP. Además, ninguno de los pacientes en el grupo A mostró una PAP media superior a 20mmHg, mientras que en el grupo B, el 67% de las mediciones fue mayor que el nivel de referencia. Conclusiones: Reafirmamos que la suplementación con citrulina es efectiva para reducir la HP postoperatoria y que los biomarcadores podrían evidenciar el estado del paciente como una aplicación de medicina traslacional.A hipertensão pulmonar (HP) é uma das principais causas de morbimortalidade entre pacientes com cardiopatia congênita (DCC) e também uma complicação potencialmente grave após o reparo cirúrgico. A citrulina oral, precursora da síntese do NO, é segura e eficaz para diminuir o risco de HP pós-operatória. Objetivo: O objetivo do presente estudo foi investigar em pacientes pediátricos as alterações dos metabólitos plasmáticos da citrulina, arginina, homocisteína e óxido nítrico (NO) e pressões da artéria pulmonar (PAP) pré-pós-cirurgia cardíaca, a fim de descrever nosso status populacional com com relação ao risco de hipertensão pulmonar e procure potenciais biomarcadores para detecção e tratamento precoces. Principais resultados / Discussão: 16 pacientes pediátricos argentinos com DCC submetidos à circulação extracorpórea foram randomizados em dois grupos: (A) com e (B) sem suplementação peri-operatória de citrulina. Descobrimos que os níveis médios de citrulina plasmática antes da cirurgia eram menores nos dois grupos em relação aos valores referenciais, provavelmente devido ao mau estado nutricional de nossos pacientes; somente o grupo A superou no pós-operatório o nível mínimo recomendado para evitar HP. Além disso, nenhum dos pacientes do grupo A apresentou PAP média superior a 20 mmHg, enquanto no grupo B, 67% das medidas foram ≥ acima do nível de referência. Conclusões: Reafirmamos que a suplementação com citrulina é eficaz na redução da hipertensão pulmonar no pósoperatório e os biomarcadores podem evidenciar o status do paciente como aplicação de medicamento translacional.Fil: Silvera Ruiz, Silene Maite. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Estudios de las Metabolopatías Congénitas; Argentina. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Grosso, Carola L.. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Est.de Las Metabolopatias Congenitas. Cátedra de Clinica Pediatrica; ArgentinaFil: Tablada, Margot. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Cabrera, Marcelo. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; ArgentinaFil: Dodelson de Kremer, Raquel. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Est.de Las Metabolopatias Congenitas. Cátedra de Clinica Pediatrica; ArgentinaFil: Juaneda, Ernesto. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; ArgentinaFil: Laróvere, Laura Elena. Gobierno de la Provincia de Cordoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Est.de Las Metabolopatias Congenitas. Cátedra de Clinica Pediatrica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin
Understanding why women don’t choose engineering degrees
Despite the continuous efforts of governments and universities to avoid the underrepresentation of women entering engineering degrees, the trend has not reverted, and this is a general fact all over the world. This fact goes against the tendency of a growing ratio of women in tertiary education, so causes must be investigated. This research examines two main questions: Is it possible to break the invisible barriers that prevent girls from entering in engineering degrees by means of an engineering project or activity? And are there important misconceptions about the role of women in engineering professions and about engineering itself among high school girls? An extensive survey has been carried out between three groups of students: students of the last years of high school (834), students of the first year of engineering degrees (319), and students of the first year of sciences degrees (209). A set of visits to the high schools was developed and a contest of engineering projects was carried out too. The results show that there are important misconceptions in the knowledge that high school students have about engineering degrees and engineering. The visits and the project contest had a good impact that encouraged girls to take engineering activities in their curricula. The main finding is that even though girls see engineering professions as very well valued, they are convinced that engineering is not a profession for women, which suggests that there are educational barriers acquired during earlier stages of their lives
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