547 research outputs found
Sobre un híbrido nuevo de Geum L. (Rosaceae) en la provincia de Teruel
Se comunica el hallazgo de un nuevo híbrido del género Geum L.
(Rosaceae) localizado en la Sierra de Gúdar (Teruel) que denominamos Geum ×
gonzaloi, y cuyos parentales son G. hispidum y G. urbanum
Evolutionary dynamics of insertion sequences in relation to the evolutionary histories of the chromosome and symbiotic plasmid genes of Rhizobium etli populations
Insertion sequences (IS) are mobile genetic elements that are distributed in many prokaryotes. In particular, in the genomes of the symbiotic nitrogen-fixing bacteria collectively known as rhizobia, IS are fairly abundant in plasmids or chromosomal islands that carry the genes needed for symbiosis. Here, we report an analysis of the distribution and genetic conservation of the IS found in the genome of Rhizobium etli CFN42 in a collection of 87 Rhizobium strains belonging to populations with different geographical origins. We used PCR to generate presence/absence profiles of the 39 IS found in R. etli CFN42 and evaluated whether the IS were located in consistent genomic contexts. We found that the IS from the symbiotic plasmid were frequently present in the analyzed strains, whereas the chromosomal IS were observed less frequently. We then examined the evolutionary dynamics of these strains based on a population genetic analysis of two chromosomal housekeeping genes (glyA and dnaB) and three symbiotic sequences (nodC and the two IS elements). Our results indicate that the IS contained within the symbiotic plasmid have a higher degree of genomic context conservation, lower nucleotide diversity and genetic differentiation, and fewer recombination events than the chromosomal housekeeping genes. These results suggest that the R. etli populations diverged recently in Mexico, that the symbiotic plasmid also had a recent origin, and that the IS elements have undergone a process of cyclic infection and expansion
On the relationship between pump chirp and single-photon chirp in spontaneous parametric downconversion
We study the chronocyclic character, i.e. the joint temporal and spectral
properties, of the single-photon constituents of photon pairs generated by
spontaneous parametric down conversion. In particular we study how single
photon properties, including purity and single-photon chirp, depend on photon
pair properties, including the type of signal-idler spectral and correlations
and the level of pump chirp.Comment: 13 pages, 6 figure
Slow relaxation dynamics of clogs in a vibrated granular silo
We experimentally explore the vibration-induced unclogging of arches halting the flow in a two-dimensional silo. The endurance of arches is determined by carrying out a survival analysis of their breaking times. By analyzing the dynamics of two morphological variables, we demonstrate that arches evolve toward less regular structures and it seems that there may exist a certain degree of irregularity that the arch reaches before collapsing. Moreover, we put forward that σ (the standard deviation of all angles between consecutive beads) describes faithfully the morphological evolution of the arch. Focusing on long-lasting arches, we study σ calculating its two-time autocorrelation function and its mean-squared displacement. In particular, the apparent logarithmic increase of the correlation and the decrease of the mean-squared displacement of σ when the waiting time is increased reveal a slowing down of the dynamics. This behavior is a clear hallmark of aging phenomena and confirms the lack of ergodicity in the unclogging dynamics. Our findings provide new insights on how an arch tends to destabilize and how the probability that it breaks with a long sustained vibration decreases with time.Fil: Guerrero Borges, Veronica. Universidad de Navarra; EspañaFil: Pugnaloni, Luis Ariel. Universidad Tecnológica Nacional. Facultad Regional La Plata. Departamento de Ingeniería Mecánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Lozano, C.. Universitat Konstanz; AlemaniaFil: Zuriguel, I.. Universidad de Navarra; EspañaFil: Garcimartín, A.. Universidad de Navarra; Españ
Risk factors associated with burnout syndrome in teachers
El síndrome de Burnout es una repuesta al estrés crónico laboral que se caracteriza por la ausencia de motivación, desinterés, malestar e insatisfacción laboral que afecta a determinados grupos profesionales. Desde una perspectiva psicológica, se interpreta como un proceso que implica una reducida realización personal en el trabajo, cansancio emocional y despersonalización. El desarrollo del síndrome conlleva un deterioro físico y psíquico, y consecuencias negativas en el ámbito personal y laboral. Los docentes son uno de los colectivos más afectados por este síndrome. El objetivo de este trabajo es presentar una revisión bibliográfica de las principales variables asociadas con el síndrome de Burnout en docentes. Se han encontrado numerosos factores de riesgo asociados con el síndrome de Burnout. Estos factores de riesgo se pueden agrupar en factores individuales (sociodemográficos y personales) y organizacionales (ambiente laboral y condiciones laborales). Estos resultados se deberían de tener en cuenta cuando se trabaja en la prevención de Burnout en profesores.Burnout syndrome is a response to chronic job stress characterized by a lack of motivation, disinterest, internal unrest and job dissatisfaction, which seems to especially affect certain professional groups. From a psychosocial perspective, it is conceptualized as a process that involves reduced personal accomplishment at work, emotional exhaustion and depersonalization. Burnout development involves deterioration in physical and mental health and has negative consequences in personal and work spheres. Teachers are considered among the professional groups more affected by Burnout syndrome. The aim of this work is to present a bibliography review of the main variables associated with Burnout syndrome in teachers. Many risk factors associated with Burnout syndrome were identified. Two types of factors were distinguished: individual (sociodemographic and personality variables) and organizational factors (work environment and work conditions). The results in this study should be taken into account when working to prevent Burnout syndrome in teachers.peerReviewe
Spectroscopy, leptonic decays and the nature of heavy quarkonia
We examine the electronic width ratios of Upsilon resonances below the BBbar
threshold by means of an effective (Cornell-type) QCD potential incorporating
1/m_b corrections obtained from a prior fit to the bottomonium spectrum. From
our analysis we conclude that the Upsilon(2S) and Upsilon(3S) states should
belong to the strong-coupling (nonperturbative) regime while the Upsilon(1S)
state should belong to the weak-coupling (perturbative) regime, in agreement
with a previous study based on radiative decays.Comment: 8 page
Anti-tumor effects of anti-Semaphorin 4D antibody unravel a novel pro-invasive mechanism of vascular targeting agents
One of the main consequences of inhibition of neovessel growth and vessel pruning produced by angiogenesis inhibitors is increased intratumor hypoxia. Growing evidence indicates that tumor cells escape from this hypoxic environment to better nourished locations, presenting hypoxia as a positive stimulus for invasion. In particular, anti-VEGF/R therapies produce hypoxia-induced invasion and metastasis in a spontaneous mouse model of pancreatic neuroendocrine cancer (PanNET), RIP1-Tag2. Here, a novel vascular-targeting agent targeting semaphorin 4D (Sema4D) demonstrated impaired tumor growth and extended survival in the RIP1-Tag2 model. Surprisingly, although there was no induction of intratumor hypoxia by anti-Sema4D therapy, the increase in local invasion and distant metastases was comparable with the one produced by VEGFR inhibition. Mechanistically, the antitumor effect was due to an alteration in vascular function by modification of pericyte coverage involving platelet-derived growth factor B. On the other hand, the aggressive phenotype involved a macrophage-derived Sema4D signaling engagement, which induced their recruitment to the tumor invasive fronts and secretion of stromal cell–derived factor 1 (SDF1) that triggered tumor cell invasive behavior via CXCR4. A comprehensive clinical validation of the targets in different stages of PanNETs demonstrated the implication of both Sema4D and CXCR4 in tumor progression. Taken together, we demonstrate beneficial antitumor and prosurvival effects of anti-Sema4D antibody but also unravel a novel mechanism of tumor aggressivity. This mechanism implicates recruitment of Sema4D-positive macrophages to invasive fronts and their secretion of proinvasive molecules that ultimately induce local tumor invasion and distant metastasis in PanNETs.This work is supported by research grants from ERC (ERC-StG-281830) EU-FP7, MinECO (SAF2016-79347-R), ISCIII Spain (AES, DTS17/00194) and AGAUR-Generalitat de Catalunya (2017SGR771). Some of these include European Development Regional Funds (ERDF “a way to achieve Europe”). Vaccinex Inc. provided reagents and research money (<20.000 Eur) to support this work
Energy dense salty food consumption frequency is associated with diastolic hypertension in Spanish children
High blood pressure (BP) is a risk factor for cardiovascular disease and sodium consumption is related to high BP. Moreover, sugar-sweetened beverages (SSB) and the Dietary Approach to Stop Hypertension (DASH) influence BP. For this reason, we investigated whether: 1) children with risk of elevated BP had a higher consumption frequency (CF) of energy-dense salty foods (EDSF), high-sugary foods (HSF) and SSB or a low DASH score; and 2) children with a higher CF of EDSF showed a worse anthropometric and metabolic profile. Anthropometry, BP and general biochemical parameters were measured in 687 Spanish children (5-16 years) with normal or excess weight. A food frequency questionnaire was used to calculate EDSF, HSF and SSB consumption, and modified DASH score. Results showed that sex and pubertal stage influenced modified DASH score. Diastolic hypertension was associated to higher CF of EDSF in the whole sample and to higher CF of SSB in pubertal children, both independently of nutritional status. In addition, CF of EDSF was positively associated with CF of HSF and SSB and inversely associated with modified DASH score. Targeted policies and intervention programs, specific for different age ranges, should be established that aim to reduce salt consumption from snacks and processed foods, which could reduce HSF and SSB consumption as well
Análisis bayesiano de variables relacionadas con el desarrollo del síndrome de Burnout en profesionales sanitarios
Burnout syndrome has a high incidence among professional healthcare and social workers. This leads to deterioration in the quality of their working life and affects their health, the organization where they work and, via their clients, society itself. Given these serious effects, many studies have investigated this construct and identified groups at increased risk of the syndrome. The present work has 2 main aims: to compare burnout levels in potential risk groups among professional healthcare workers; and to compare them using standard and Bayesian statistical analysis. The sample consisted of 108 psycho-social care workers based at 2 centers run by the Granada Council in Spain. All par-ticipants, anonymously and individually, filled in a booklet that included questions on personal information and the Spanish adaptation of the Maslach Burnout Inventory (MBI). Standard and Bayesian analysis of variance were used to identify the risk factors associated with different levels of burnout. It was found that the information provided by the Bayesian procedure complemented that provided by the standard procedure.El síndrome de Burnout tiene una alta incidencia en profesionales que realizan una labor asistencial o social, lo que implica que el deterioro de su calidad de vida laboral afecta a su propia salud, a la organización en la que desarrollan su trabajo y también, a través de los beneficiarios del mismo, a la sociedad. Las graves consecuencias de padecer Burnout justifican la existencia de muchas investigaciones sobre dicho constructo y sobre la identificación de los grupos de riesgo asociados al mismo. El presente trabajo tiene un doble objetivo, por una parte comparar los niveles de Burnout en posibles grupos de riesgo entre los profesionales sanitarios; y por otra, realizar las comparaciones utitizando procedimientos de análisis estadístico clásico y bayesiano. Participan 108 profesionales que trabajan en atención psicosocio-sanitaria, en dos centros de la Diputación de Granada. Todos ellos respondieron, de forma anónima e individual, a un cuadernillo en el que se incluyen datos personales así como la adaptación a población española del Maslach Burnout Inventory (MBI). Se utilizan análisis de varianza clásico y bayesiano en la identificación de factores de riesgo asociados a diferentes niveles de Burnout. Se comprueba que la información ofrecida por el procedimiento bayesiano permite complementar la ofrecida por el procedimiento clásico
Preparation and characterization of micro-nano engineered targets for high-power laser experiments
[EN] The continuous development of ultra-fast high-power lasers (HPL) technology with the ability of working at unprecedented repetition rates, between 1 and 10 Hz, is raising the target needs for experiments in the different areas of interest to the HPL community. Many target designs can be conceived according to specific scientific issues, however to guarantee manufacturing abilities that enable large number production and still allow for versatility in the design is the main barrier in the exploitation of these high repetition rate facilities. Here, we have applied MEMS based manufacturing processes for this purpose. In particular, we have focused on the fabrication and characterization of submicrometric conductive membranes embedded in a silicon frame. These kinds of solid targets are used for laser-driven particle acceleration through the so-called Target Normal Sheath Acceleration mechanism (TNSA). They were obtained by top-down fabrication alternating pattern transfer, atomic layer deposition, and selective material etching. The adaptability of the approach is then analyzed and discussed by evaluating different properties of targets for use in laser-driven particle acceleration experiments. These characteristics include the surface properties of membranes after fabrication and the high density of the target array. Finally, we were able to show their efficiency for laser-driven proton acceleration in a series of experiments with a 3 TW table-top laser facility, achieving stable proton acceleration up to 2 MeV.The authors highly appreciate the collaboration of Radosys (Budapest) which provided CR-39 detector material, etching bath, and readout equipment. This project has been financed by the Spanish Ministry for Economy and Competitiveness within the Retos-Colaboracion 2015 initiative, ref. RTC-2015-3278-1. P. Mur has received a grant of the Garantia Juvenil 2015 program. This work has made use of the Spanish ICTS Network MICRONANOFABS partially supported by MEINCOM.Zaffino, R.; Seimetz, M.; Quirión, D.; Ruiz-De La Cruz, A.; Sánchez, I.; Mur, P.; Benlliure, J.... (2018). Preparation and characterization of micro-nano engineered targets for high-power laser experiments. Microelectronic Engineering. 194:67-70. https://doi.org/10.1016/j.mee.2018.03.011S677019
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