2,077 research outputs found
Variables sociodemográficas como predictores de estilos de vida en estudiantes de educación media general
El objetivo de la presente investigación fue analizar la relación
entre las variables sociodemográficas y el estilo de vida
en adolescentes de educación media general. La muestra
estuvo conformada por 176 estudiantes. Se construyó un
cuestionario sobre estilo de vida estructurado en la primera
parte con información sobre datos sociodemográficos:
edad, sexo, ocupación y grado de instrucción de los padres,
lugar de residencia del estudiante y en la segunda parte
factores vinculados con el estilo de vida, dicho instrumento
cuenta con validez y confiabilidad de 0.806. Resultados: Se
estableció correlación con las variables relacionadas con
el grado de instrucción de la madre además de la ocupación
de la madre y del padre, en lo que concierne a las variables
sexo, edad, ocupación del estudiante, nivel de instrucción del
padre y el lugar de residencia del estudiante demostraron no
tener significancia con el estilo de vida de los estudiantes.
Conclusión: los resultados evidencian una vez más la influencia
que tiene la familia y su composición en la adquisición de
los estilos de vida, en este caso el grupo presentó un estilo
de vida medianamente desfavorable donde la mayoría de
los jóvenes pertenecen a una familia monoparental, ello
corrobora lo planteado por Arenas (2008) donde afirma que
cuando existen elementos positivos dentro del sistema familiar
ello permite que se eviten situaciones de riesgo social, estos
elementos favorecen la salud dentro de la dinámica familia
Stealth and equiluminous materials for scattering cancellation and wave diffusion
[EN] We report a procedure to design two-dimensional acoustic structures with prescribed scattering properties. The structures are designed from targeted properties in the reciprocal space so that their structure factors, i.e. their scattering patterns under the Born approximation, exactly follow the desired scattering properties for a set of wavelengths. The structures are made of a distribution of rigid circular cross-sectional cylinders embedded in air. We demonstrate the efficiency of the procedure by designing two-dimensional stealth acoustic materials with broadband back-scattering suppression independent of the angle of incidence and equiluminous acoustic materials exhibiting broadband scattering of equal intensity also independent of the angle of incidence. The scattering intensities are described in terms of both single and multiple scattering formalisms, showing excellent agreement with each other, thus validating the scattering properties of each material.This work has been funded by the project Conseil Regional des Pays de la Loire HYPERMETA under the program Etoiles Montantes of the Region Pays de la Loire, by the project Agence Nationale de la Recherche ANR-RGC METARoom [grant number (ANR-18-CE08-0021)] and by the project PID2020112759GB-I00 of the Ministerio de Ciencia e Innovacion.Kuznetsova, S.; Groby, JP.; García-Raffi, LM.; Romero-García, V. (2021). Stealth and equiluminous materials for scattering cancellation and wave diffusion. Waves in Random and Complex Media. https://doi.org/10.1080/17455030.2021.194863
Plant Metabolites in Plant Defense Against Pathogens
Medicinal plants are widely used worldwide to treat various diseases. Its widespread use is due in part to the cultural acceptance of traditional medicine in different regions of the world, as well as its effectiveness in treating various diseases. Many of its active substances or secondary metabolites are formed to a response of various situations that generate stress in their habitat, such as sudden changes in environmental temperature, humidity, rain, drought, and infections by phytopathogens (fungi, bacteria, viruses, nematodes, protozoa). The production of these secondary metabolites is a mechanism of defense of plants. In this context, the objective of this chapter is to study the secondary metabolites of medicinal plants that could have a promising application in the control of different phytopathogens in crops of agricultural and economic interest
Utilization of muddy detritus as organic matter source by the fan mussel Pinna nobilis.
The knowledge of the feeding habits in marine species is fundamental to better understand their relationship with the environment. Although phytoplankton has been traditionally reported as the main food source consumed by the Mediterranean fan mussel Pinna nobilis, recent studies have revealed that detritus represents an important food source for this species. We analysed the degree of acceptance of muddy detritus and the utilisation of its organic matter (OM) by P. nobilis on a group of 21 individuals (30.3-59.7 cm of total shell height (Ht)). The specimens were collected between July and September 2012 in two areas (43°04´25” N; 5°46´7” E and 43°04´34” N; 5°47´32” E) of the Embiez archipelago, northwestern Mediterranean (France). Our studies show that P. nobilis retains high quantities of OM from muddy detritus (47.50 ± 11.23% of filtered OM) irrespectively of shell size. Smaller individuals, however, actively filter more detritus than large ones. The values of retained OM, together with previous studies on stomach contents, suggest that muddy detritus is a more important OM source than phytoplankton for this species
Embryonic Organ Transplantation: The New Era of Xenotransplantation
Here, we review the recent advances towards the use of organs from embryonic donors, antecedent investigations, and the latest work from our own laboratory exploring the utility for transplantation of embryonic kidney as an organ replacement therapy. In addition, we have recently reported, for the first time, that it is possible to create a long-term biobank of kidney precursors as an unlimited source of organs for xenotransplantation, facilitating inventory control and the distribution of organs
Los Dinosaurios de Morella (Nota preliminar)
En esta nota se da cuenta de las campañas llevadas a cabo, en los alrededores de Morella (Castellón, España), para la extracción de restos de Dinosaurios; se indican los ejemplares obtenidos hasta el momento y se hace un breve comentario de las piezas ya estudiadas
Notes on the ecology and distribution of a water flea complex (Anomopoda, Daphniidae) revealed by new DNA barcodes in the Iberian Peninsula
Available DNA barcodes of freshwater zooplankton are scarce in regions like
the Iberian Peninsula, which harbours many rare and endemic species and is
considered a hotspot of crustacean biodiversity. Recently, a new species of
Ceriodaphnia (Cladocera: Daphniidae) was described using morphological analysis of specimens in the Mediterranean region and molecular data on a single
locality in southern Spain. In our study, we detected the presence of the newly
discovered taxa and here, we provide new DNA sequences on the barcoding region mitochondrial cytochrome c oxidase I together with ecological information
of the recently described Ceriodaphnia smirnovi. Additionally, we built a molecular phylogenetic tree and genetically compared these specimens with previously
available mitochondrial DNA sequences and with new sequences of the genus recovered in Iberia. Our data suggest that this morphospecies might contain some
cryptic taxa and might be more common than previously thought, occupying
temporary to semi-permanent ecosystems, with vegetation and highly variable
pH and turbidity conditions. Moreover, the existence of a non-identified clade
within our phylogenetic tree requires additional morphological research. Our
study highlights the need for further research on microcrustacean biota to better
constrain its spatial boundaries, phylogenetic relationship and determine species
hiding cryptic diversityDepartamento de Estratigrafía y Paleontologí
Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study
In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insight into the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organic substances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis (PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBO solutions studied. The EEM peak locations (λex/λem) of these components were 310?330 nm/400?420 nm (C1), 340?360 nm/450?500 nm (C2), and 285 nm/335?380 nm (C3). Slight variations of the maximum position of each component with the solution pH were observed. The interaction of SBO with Fe(III) was characterized by determining the stability constants of the components with Fe(III) at different pH values, which were in the order of magnitude of the ones reported for humic substances and reached their highest values at pH = 5. Photochemical experiments employing SBO and Fe(III), with and without H2O2, showed pH-dependent trends for the evolution of the modeled components, which exhibited a strong correlation with the efficiency reported for the photo-Fenton processes in the presence of SBO at different pH values.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
- …