3,278 research outputs found
Supporting variables for biological effects measurements in fish and blue mussels
Biological effects measurements in fish and blue mussel are fundamental in marine
environmental monitoring. Nevertheless, currently used biomarkers may be confounded by basic physiological phenomena, such as growth, reproduction, and feeding, as well as thereby associated physiological variation. Here, we present a number
of supporting variables, which are essential to measure in order to obtain reliable biological effects data, facilitate their interpretation, and make valid comparisons. For fish,
these variables include: body weight, body length, condition, gonad maturation status,
various somatic indices, age, and growth. For blue mussels, these variables include:
volume, flesh weight, shell weight, and condition. Also, grossly visible anomalies, lesions, and parasites should be recorded for both fish and blue mussels. General confounding factors and their effects are described, as well as recommendations for how
to handle themPostprint
Experimental study of emergent ground state behavior in Gd1-xCexNi5 (x = 0; 0.2; 0.5; 0.8 and 1) melt-spun ribbons
The ground state physical properties of Gd1-xCexNi5 (x = 0; 0.2; 0.5; 0.8 and 1) melt-spun ribbons were investigated by X-ray diffraction, magnetization and specific heat measurements. The produced ribbon samples are single phases with the hexagonal CaCu5-type crystal structure. The magnetic transition temperature decreases with increasing Ce content. At a temperature around 100 K for the CeNi5 melt-spun ribbon, the spin fluctuations effect is visible.This research work was supported partially by VEGA 1/0404/21; VEGA 1/0705/20; VEGA 1/0053/19, and APVV-16-0079
Nivel de formación sobre sexualidad humana en estudiantes del primer ciclo en la Universidad Católica Santo Toribio de Mogrovejo, año 2010
La sexualidad humana es un concepto que abarca distintos ámbitos. Generalmente la sociedad tiende a relacionarlo con la parte reproductiva, sin embargo no solo atañe a lo sexual propiamente dicho, pues también comprende a la parte afectiva, de allí que se hable de una salud sexual y afectiva. El presente trabajo tiene como finalidad determinar el nivel de formación sobre sexualidad humana en estudiantes del primer ciclo en la Universidad Católica Santo Toribio de Mogrovejo, año 2010. Para la realización de la investigación se empleó un estudio descriptivo primario de tipo transversal, utilizándose el consentimiento informado para proceder a la encuesta elaborada por los autores en conjunto con un experto en el tema, siendo ésta revisada por dos sacerdotes y una psicóloga, y previamente empleada en prueba piloto. Ésta se aplicó en el muestreo obtenido estadísticamente
de una población total de 1496 estudiantes 2010-I. Resultando los sujetos a investigar 424 estudiantes, considerados según estratos según facultad: ciencias empresariales, derecho, humanidades, ingeniería y medicina. Sin embargo la muestra de estudio se incrementó durante el proceso, haciendo un total de 439 estudiantes. Para el análisis de los datos se empleó tablas de frecuencias, diagramas de barras, diagrama de sectores y el programa Estadístico Excel. Se concluyó que de los 439 estudiantes del primer ciclo de USAT 2010-I entrevistados: el 19% presentó nivel alto de formación sobre sexualidad humana; el 62%, predominante, presentó un nivel medio, mientras que el restante, 18%, presentó nivel bajo
Kinetico-mechanistic study on the C-H bond activation of primary benzylamines; cooperative and solid-state cyclopalladation on dimeric complexesss
The cyclometallation reactions of dinuclear μ-acetato complexes of the type [Pd(AcO)(μ-AcO)L]2 (L = 4-RC6H4CH2NH2, R = H, Cl, F, CF3), a process found to occur readily even in the solid state, have been studied from a kinetico-mechanistic perspective. Data indicate that the dinuclear acetato bridged derivatives are excellent starting materials to activate carbon-hydrogen bonds in a facile way. In all cases the established concerted ambiphilic proton abstraction by a coordinated acetato ligand has been proved. The metallation has also been found to occur in a cooperative manner, with the metallation of the first palladium unit of the dimeric complex being rate determining; no intermediate mono-metallated compounds are observed in any of the processes. The kinetically favoured bis-cyclopalladated compound obtained after complete C-H bond activation does not correspond to the final isolated XRD-characterized complexes. This species, bearing the classical open-book dimeric form, has a much more complex structure than the final isolated compound, with different types of acetato ligand
Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer
We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.We are thankful for support from MICINN (MAT2013-46753-C2-1-P, MAT2013-46502-C2-1/2-P and CTQ2011-26507), Eusko Jaurlaritza (S-PE13UN016) and Generalitat Valenciana PrometeoII/2014/076
Assessing environmental quality status by integrating chemical and biological effect data: The Cartagena coastal zone as a case
En prensa1,953
Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept
We present a proof of concept on the coupling of radio astronomical receivers
and spectrometers with chemical reactorsand the performances of the resulting
setup for spectroscopy and chemical simulations in laboratory astrophysics.
Several experiments including cold plasma generation and UV photochemistry were
performed in a 40\,cm long gas cell placed in the beam path of the Aries 40\,m
radio telescope receivers operating in the 41-49 GHz frequency range interfaced
with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz
resolution.
The impedance matching of the cell windows has been studied using different
materials. The choice of the material and its thickness was critical to obtain
a sensitivity identical to that of standard radio astronomical observations.
Spectroscopic signals arising from very low partial pressures of CH3OH,
CH3CH2OH, HCOOH, OCS,CS, SO2 (<1E-03 mbar) were detected in a few seconds. Fast
data acquisition was achieved allowing for kinetic measurements in
fragmentation experiments using electron impact or UV irradiation. Time
evolution of chemical reactions involving OCS, O2 and CS2 was also observed
demonstrating that reactive species, such as CS, can be maintained with high
abundance in the gas phase during these experiments.Comment: Accepted for publication in Astronomy and Astrophysics in September
21, 2017. 16 pages, 18 figure
Evolution of Group Galaxies from the First Red-Sequence Cluster Survey
We study the evolution of the red galaxy fraction (f_red) in 905 galaxy
groups with 0.15 < z < 0.52. The galaxy groups are identified by the
`probability Friends-of-Friends' algorithm from the first Red-Sequence Cluster
Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity
in the properties of the red-sequence of the group galaxies, indicating that
the luminous red-sequence galaxies in the groups are already in place by z~0.5
and that they have a formation epoch of z>2. In general, groups at lower
redshifts exhibit larger f_red than those at higher redshifts, showing a group
Butcher-Oemler effect. We investigate the evolution of f_red by examining its
dependence on four parameters, which can be classified as one intrinsic and
three environmental: galaxy stellar mass (M_*), total group stellar
mass(M_{*,grp}, a proxy for group halo mass), normalized group-centric radius
(r_grp), and local galaxy density (Sigma_5). We find that M_* is the dominant
parameter such that there is a strong correlation between f_red and galaxy
stellar mass. Furthermore, the dependence of f_red on the environmental
parameters is also a strong function of M_*. Massive galaxies (M_* > 10^11
M_sun) show little dependence of f_red on r_grp, M_{*,grp}, and Sigma_5 over
the redshift range. The dependence of f_red on these parameters is primarily
seen for galaxies with lower masses, especially for M_* < 10^{10.6} M_{sun}. We
observe an apparent `group down-sizing' effect, in that galaxies in lower-mass
halos, after controlling for galaxy stellar mass, have lower f_red. We find a
dependence of \fred on both \rgrp and \SigmaF after the other parameters are
controlled. At a fixed \rgrp, there is a significant dependence of f_red on
Sigma_5, while r_grp gradients of f_red are seen for galaxies in similar
Sigma_5 regions. This indicates .....Comment: ApJ accepte
Socioeconomic Factors and Abdominal Obesity in European and Brazilian Adolescents: Data from Two Observational Studies
The curse of the uncultured fungus
The international DNA sequence databases abound in fungal sequences not annotated beyond the kingdom level, typically bearing names such as “uncultured fungus”. These sequences beget low-resolution mycological results and invite further deposition of similarly poorly annotated entries. What do these sequences represent? This study uses a 767,918-sequence corpus of public full-length fungal ITS sequences to estimate what proportion of the 95,055 “uncultured fungus” sequences that represent truly unidentifiable fungal taxa – and what proportion of them that would have been straightforward to annotate to some more meaningful taxonomic level at the time of sequence deposition. Our results suggest that more than 70% of these sequences would have been trivial to identify to at least the order/family level at the time of sequence deposition, hinting that factors other than poor availability of relevant reference sequences explain the low-resolution names. We speculate that researchers’ perceived lack of time and lack of insight into the ramifications of this problem are the main explanations for the low-resolution names. We were surprised to find that more than a fifth of these sequences seem to have been deposited by mycologists rather than researchers unfamiliar with the consequences of poorly annotated fungal sequences in molecular repositories. The proportion of these needlessly poorly annotated sequences does not decline over time, suggesting that this problem must not be left unchecked
- …