4,335 research outputs found
Peer Victimization in Overweight Adolescents and Its Effect on Their Self-Esteem and Peer Difficulties
This study has three objectives: to examine whether adolescents who perceive themselves as overweight differ from others in terms of offline victimization at school, cybervictimization, self-esteem, and difficulties relating to peers; to examine the possible effects of offline and cybervictimization on self-esteem and difficulties relating to peers; and to examine the possible moderating role of perceiving oneself as overweight on those effects. Previously validated questionnaires were applied to a sample of 3145 adolescents in Asturias (Spain). Descriptive, inferential, correlational, and structural equation analyses were performed. Adolescents who perceived themselves as overweight reported being victims of both offline victimization and most forms of cybervictimization to a greater extent than those who did not perceive themselves as overweight. They also reported lower self-esteem and more peer difficulties (shyness or social anxiety). In both groups of adolescents, victimization and cybervictimization were correlated with each other, both types of victimization had direct, negative effects on self-esteem, and self-esteem in turn had a direct, negative effect on peer difficulties. Furthermore, offline victimization had a direct, positive effect on peer difficulties. Perceiving oneself as overweight moderated the effect of self-esteem on peer difficulties. In adolescents perceiving themselves as overweight, low self-esteem was a stronger risk factor of peer difficulties than in the rest of the adolescents. With high overall self-esteem there were no significant differences in peer difficulties between the adolescents perceiving themselves as overweight and the rest of the adolescents
Engendering epidemiology
Contributions from the Spanish Research Network for Health and Gende
Bibliometric mapping of the trends and contributions of scientific publications to risk and crisis communication regarding South America
Risk and crisis communication (R&CC) are crucial elements of managing vulnerability to big threats. This paper aims to explore the trends and contributions of scientific publications to R&CC about South America. Through the examination of 330 papers listed in the Web of Science database, the current study conducted a thorough overview between 1998 (oldest study) and 2021 (cut-off date) of bibliometric networks (keyword co-occurrence map, co-authorship maps, and author co-citation map) and multivariate statistical models (principal component analysis, compositional linear model). We address main communication factors, links between communication factors and countries, main academic cooperation networks, determinants of publication trends, and most cited authors. 28 R&CC factors were mapped and their relative importance to various hazards was examined. Most of these factors were intended to strengthen the communication system and increase risk knowledge of vulnerable people. Chile, Colombia, and Ecuador were mostly focused on strengthening R&CC. Brazil and Argentina were best represented with health and exposure to pollutants communication. Publications on R&CC are determined by the level of wealth, tourist arrivals, and the number of people affected by disasters. The compositional analysis revealed that the behavior of publications determinants could have opposite tendencies depending on the threatsâ multidimensionality. To the best of our knowledge, this is the first R&CC study on South America to use CoDA in a bibliometric analysisPostprint (published version
Low-frequency phonons in carbon nanotubes: A continuum approach
7 pågs.; 6 figs.; 2 apéndices ; PACS number s : 68.65. k, 63.22. mLow-frequency phonons in carbon nanotubes are studied using a continuum model which allows consideration of an arbitrary wall thickness for the nanotube. Phonon dispersion relations are calculated for two archetypal examples of carbon nanotubes, the (5,5) and (10,10) tubes. The dependence of the radial breathing mode frequency at Πon the inverse nanotube diameter is verified within this model; furthermore, we prove it to hold for all pure modes within the thin-shell approximation. The effect of the nanotube wall thickness on the eigenfrequencies of carbon nanotubes is also analyzed, and a criterion to fix this parameter within a continuum model is presented. We compare our results to other continuum approaches, and show that by choosing the appropriate parameters, excellent agreement with recent first-principles calculations can be achieved. © 2006 The American Physical Society.This work has been partly supported by the Spanish DGES Grant No. MAT
2002-04540-C05-03 and the Vicerrectorado de Relaciones
Internacionales UCLM.Peer Reviewe
Taxonomic differences between Pinus sylvestris and P. uncinata revealed in the stomata and cuticle characters for use in the study of fossil material
Taxonomic differences in the needle epidermis characteristics of Pinus sylvestris L. and Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells. P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while P. uncinata showed small, lateral subsidiary cells and non-differentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of P. uncinata was also larger in diameter (15.1 ± 1.8 ”m P. sylvestris; 21.1 ± 2.8 ”m P. uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the cuticular thickenings â all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features
Novel âgel demineralizingâ method for protein recovery from fat rendering waste stream based on its gelling properties
peer-reviewedFat rendering is a common process in the meat industry, whereby fatty or oily materials are melted away or cooked from the solid portion of the animal tissue. Once the fat, and more solid protein in the form of greaves, has been removed a co-product called glue water or stick water is produced which in generally considered a waste product. This study was established to investigate ways to revalorise this product and reduce the economic and environmental impact of this waste material. Proximate characterisation shows it contains 1.1â1.3% w/w of protein along with similar concentration of ashes (1.3% w/w). While low in protein this is a key pollutant if the product is disposed of, and could also represent an interesting protein source for downstream applications. In order to recover these proteins the salt has to be removed. Therefore, after the techno-functional properties of the raw material and of the recovered proteins were evaluated, especially those related to gelling formation, a new demineralizing method based on the excellent gelling properties of these proteins was developed and results compared with those obtained from three different ultrafiltration membranes (10, 3 and 1âŻkDa MWCO). Protein recovery was greater for the new method (79â90%) (50â77%); however, the amount of salt removed was higher when ultrafiltration was employed (90% compared to 81%)
Object Tracking from Unstabilized Platforms by Particle Filtering with Embedded Camera Ego Motion
Visual tracking with moving cameras is a challenging task. The global motion induced by the moving camera moves the target object outside the expected search area, according to the object dynamics. The typical approach is to use a registration algorithm to compensate the camera motion. However, in situations involving several moving objects, and backgrounds highly affected by the aperture problem, image registration quality may be very low, decreasing dramatically the performance of the tracking. In this work, a novel approach is proposed to successfully tackle the tracking with moving cameras in complex situations, which involve several independent moving objects. The key idea is to compute several hypotheses for the camera motion, instead of estimating deterministically only one. These hypotheses are combined with the object dynamics in a Particle Filter framework to predict the most probable object locations. Then, each hypothetical object location is evaluated by the measurement model using a spatiogram, which is a region descriptor based on color and spatial distributions. Experimental results show that the proposed strategy allows to accurately track an object in complex situations affected by strong ego motion
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