582 research outputs found
Sex differences in comorbidity between substance use and mental health in adolescents: Two sides of the same coin
Background: This study aims to evaluate sex differences in alcohol and cannabis use and mental health disorders (MHD) in adolescents, and to evaluate the predictive role of mental health disorders for alcohol and cannabis use disorders (AUD and CUD respectively).
Method: A sample of 863 adolescents from the general population (53.7% girls, Mage = 16.62, SD = 0.85) completed a computerized battery including questions on substance use frequency, the Brief Symptom Inventory, the Cannabis Problems Questionnaire for Adolescents - Short version, the Rutgers Alcohol Problem Index and the DSM-IV-TR criteria for AUD and CUD. Bivariate analyses and binary logistic regressions were performed.
Results: Girls presented significantly more mental health problems and a higher prevalence of comorbidity between SUD and MHD. Obsessivecompulsive symptoms and phobic anxiety indicated a higher risk of AUD, whereas depression and interaction between hostility and obsessivecompulsive disorder indicated a higher risk of CUD.
Conclusions: Comorbidity between SUD and MHD is high among adolescents, and significantly higher among girls.
Antecedentes: el objetivo de esta investigación es evaluar las diferencias de sexo en el uso de cannabis y alcohol y en trastornos de salud mental TSM en adolescentes, y el rol predictivo de los TSM sobre los trastornos por uso de alcohol y cannabis (TUA y TUC, respectivamente).
Método: una muestra de 863 adolescentes de la población general (53, 7% chicas, edad media = 16.62, DT = 0, 85) completaron una batería informatizada sobre la frecuencia de uso de sustancias, el Inventario Breve de Síntomas, el Cuestionario de Problemas por Consumo de Cannabis - versión breve, el Índice de Rutgers de Problemas con el Alcohol y los criterios DSM-IV-TR para el TUA y TUC. Se realizaron análisis bivariados y de regresión logística binaria.
Resultados: las chicas presentaron significativamente más problemas de salud mental y mayor prevalencia de comorbilidad entre TUS y TSM. El trastorno obsesivo-compulsivo (TOC) y la ansiedad fóbica indicaron un mayor riesgo de TUA, mientras que la depresión y la interacción entre hostilidad y TOC indicaron mayor riesgo de TUC.
Conclusiones: la comorbilidad entre TUS y TSM es alta entre los adolescentes, y significativamente mayor entre las chicas
Pattern formation in a predator-prey system characterized by a spatial scale of interaction
We describe pattern formation in ecological systems using a version of the
classical Lotka-Volterra model characterized by a spatial scale which controls
the predator-prey interaction range. Analytical and simulational results show
that patterns can emerge in some regions of the parameters space where the
instability is driven by the range of the interaction. The individual-based
implementation captures realistic ecological features. In fact, spatial
structures emerge in an erratic oscillatory regime which can contemplate
predators' extinction.Comment: 5 pages, 4 figure
Analysis of the Corrosion Resistance of Bronze to Aluminium (ASTM B 824) in a Corrosive Environment Controlled with an Artificial Seawater Solution
This paper presents the analysis of corrosion resistance of bronzes to aluminum in a controlled corrosive environment. Three alloys were studied CuAl4.5; CuAl7,1 and CuAl10,1 (ASTM B824), whose chemical composition was evaluated by spectrometry (OES). To determine its metal phases, chemical attacks were carried out with FeCl3, HCl in 95% Ethanol and FeCl3, HCl, CrO3 in distilled water. The microstructures obtained were characterized by metallography using two microscopes, an optical and a scanning electron (SEM) and the phases obtained were compared. Subsequently, electrochemical corrosion tests were performed on each alloy. The electrolyte used in the tests was artificial seawater (ASTM D1141) with a pH of 10 ± 0.3. Then, the corrosion products were characterized by EDS and SEM. Once the identification phase was over, the products were removed with a 50% HCl solution. Corrosive attack damage in each microstructural matrix was identified and corrosion rates for each alloy were evaluated. Finally, the corrosion rate data were correlated with the Al and Sn percentages of the alloy. The results show that the higher the increase in aluminum, the lower the corrosion rate, for a maximum limit of Al = 10.11%; Sn = 0.13%; CR = 5,170 mpy; In addition, it was shown that these alloys are effective for marine environments with high salinity. The correlation can be used to estimate the corrosion rate for different pH of the electrolytic medium of any type of ferrous or non-ferrous alloy whose variables are dependent on its chemical composition.
Keywords: corrosion, alloy, metallography, microstructure, spectrometry, electrochemistry.
Resumen
Este artículo presenta el análisis la resistencia a la corrosión de bronces al aluminio en un ambiente corrosivo controlado. Se estudiaron tres aleaciones CuAl4,5; CuAl7,1 y CuAl10,1 (ASTM B824), cuya composición química fue evaluada por espectrometría (OES). Para determinar sus fases metálicas se realizaron ataques químicos con FeCl3, HCl en Etanol al 95% y FeCl3, HCl, CrO3 en agua destilada. Las microestructuras obtenidas se caracterizaron mediante metalografía empleando dos microscopios, un óptico y un electrónico de barrido (SEM) y se compararon las fases obtenidas. Posteriormente, se realizaron ensayos de corrosión electroquímica a cada aleación. El electrolito utilizado en los ensayos fue agua de mar artificial (ASTM D1141) con un pH 10±0.3. Sucesivamente, se caracterizaron los productos de la corrosión mediante microscopia SEM. Una vez terminada la fase de identificación, se removieron los productos con una solución al 50% HCl. Los daños del ataque corrosivo en cada matriz microestructural fueron identificados y las tasas de corrosión para cada aleación fueron evaluadas. Finalmente, se correlacionaron los datos de tasas de corrosión con los porcentajes de Al y Sn de la aleación. Los resultados muestran que a mayor aumento de aluminio existe una menor tasa de corrosión, para un límite máximo de Al=10,11%; Sn=0.13%; CR=5,170 mpy; además, se demostró que estas aleaciones son eficaces para ambientes marinos con alta salinidad. La correlación puede ser utilizada para estimar la tasa de corrosión para diferentes pH del medio electrolítico de cualquier tipo de aleación ferrosa o no ferrosa cuyas variables sean dependientes de su composición química.
Palabras claves: corrosión, aleación, metalografía, microestructura, espectrometría, electroquímica
Tratamiento quirúrgico de las roturas del tendón de Aquiles
El objetivo del trabajo fue valorar los resultados y complicaciones obtenidos tras tratamiento quirúrgico de las rupturas subcutáneas del tendón de Aquiles.
Se revisaron 26 pacientes, con un seguimiento mínimo de 1 año. Detallamos nuestra metodología en cuanto a técnica quirúrgica y manejo postoperatorio. Se valoró el resultado clínico según los siguientes parámetros: movilidad de tobillo, potencia muscular tríceps, engrosamiento tendinoso, claudicación a la marcha, atrofia gemelar, incorporación a actividades deportivas y alteraciones residuales. Los resultados fueron muy buenos en 21 casos (80,7%); buenos en 5 (19,3%), y ningún caso con resultado regular o malo. Destacamos 5 complicaciones postoperatorias inmediatas y 1 caso de reruptura, con resultado final satisfactorio. Dados los buenos resultados obtenidos, recomendamos el tratamiento quirúrgico en pacientes activos, con buen estado general, independientemente de la edad.The objective of this work was to asess the clinical results and complications with the surgical treatment for subcutaneous Achilles tendon ruptures. Twenty six patients were clinically revised with a minimal follow up of one year. We detailed the surgical technique and postoperative management of the patients. Clinical results were assessed with the next parameters: ankle joint motion; triceps muscle strength; Achilles tendinous thickened; walking limp; triceps muscle atrophy, possibility of sports practice and definitive changes. We had excellent results in 21 cases (80,7%); good results in 5 cases (19,3%) and none with fair or poor results. We detached 5 cases with immediate postoperative complications and one case of relapse, all of them with good clinical result. Our excellent and good clinical results with the surgical technique for the Achilles tendon ruptures allow us to recommend this treatment in active patients, with appropriate health conditions in spite of the age
Transverse rectification in superconducting thin films with arrays of asymmetric defects
Superconducting Nb films have been grown on top of arrays of Cu nanotriangles. These asymmetric pinning centers strongly modify the vortex lattice dynamics. Two rectification effects have been observed: (i) longitudinal ratchet effect when the input currents are injected perpendicular to the triangle reflection symmetry axis and (ii) transverse rectification effect hen the input currents are injected parallel to the triangle reflection symmetry axis and the output voltage drop occurs perpendicular to the triangle reflection symmetry axis. Increasing the applied magnetic field, the former shows a change of the output voltage polarity, the transverse output voltage does not show any polarity reversal
Los Batanes (Biescas, Spain), a roost site for horseshoe bats in the Pyrenees during the late Pleistocene
Los Batanes C4 is a cave-site in the Spanish Pyrenees, the minimum sediment calendar age was determined to be 15, 234 ± 223 cal BP by radiocarbon dating. The cave opens on the northern bank of an eastern tributary of the River Gállego, at an altitude of 1025 m. The small vertebrates recorded are mainly bats, in order of abundance Rhinolophus euryale, R. ferrumequinum, Myotis sp. and Miniopterus schreibersii. The association suggests that at the time of the accumulation the climate was reasonably similar to the current climate; we situate it within a period of local retreat of the ice-cover in the Gállego Valley during the Lateglacial. This is the highest record of these species of Rhinolophus in the Iberian Quaternary, showing that the R. euryale altitudinal range was similar to its extant range during the favourable periods of the Lateglacial. This could indicate that this taxon was relatively quick in spreading into higher regions whenever climate conditions allowed it
Cervantesiaceae: nuevo registro de una familia naturalizada para la flora de México.
Se registra por primera vez para México la especie naturalizada Acanthosyris glabrata (familia Cervantesiaceae), un árbol hemiparásito sólo conocido del noroeste de Sudamérica. Se proporciona información sobre su hábitat y se presenta una ilustración de la especie. Se propone una hipótesis de comercio maritimo entre Ecuador y México para explicar la presencia del taxón en el occidente de México, en un área que dista 3500 km de su distribución original.We register for the first time in Mexico the naturalized species Acanthosyrisglabrata (family Cervantesiaceae), a hemiparasitic tree only known from northwestern South America. We provide information about its habitat and present an illustration of the species. We propose a hypothesis of maritime commerce between Ecuador and Mexico to account for the presence of the taxon in western Mexico, in an area 3500 km away from its original known distribution
Responses of a native and a recent invader snail to warming and dry conditions: the case of the lower Ebro River
Aquatic habitats have been highly modified by human actions that reduce their native diversity and create conditions suitable for tolerant alien species. Pomacea maculata was detected in 2009 in both the alluvial plain and the final stretch of the Ebro River. Since then, a permanent population has stabilized in the littoral area of the river where the water level fluctuates according to the river discharge. Melanopsis tricarinata is an endemic snail species highly affected by the reduction in its natural habitat. Currently, the two species do not share the same reaches in the river, but the possibility exists, as the distribution of the P. maculata is constantly increasing. This study aims to analyse the diets and to assess the responses of both snails to global change. The diet of both species was analysed in the field and their responses to water warming and dryness compared under laboratory conditions. This study includes the calculation of future river water temperatures based on air temperature projections. In addition, based on water discharge management scenarios, the study estimated the increase in dry river bed area. The diet of both snail species was similar and based on Cladophora. P. maculata better resisted high temperatures and dry conditions than M. tricarinata. The projections of water temperatures showed an increase in daily temperatures, especially in summer. The hydraulic model suggested that a relevant increase in dry river bed areas will occur. Overall, these results provide insight into the global change factors that could favour P. maculata spread in the river and the reduction in suitable habitat for M. tricarinata and will be useful for future decisions of water discharge management
Excited states of exciton-polariton condensates in 2D and 1D harmonic traps
We present a theoretical description of Bogolyubov-type excitations of exciton-polariton Bose-Einstein condensates (BECs) in semiconductor microcavities. For a typical two-dimensional (2D) BEC we focus on two limiting cases, the weak-and strong-coupling regimes, where a perturbation theory and the Thomas-Fermi approximation, respectively, are valid. We calculate integrated scattering intensity spectra for probing the collective excitations of the condensate in both considered limits. Moreover, in relation to recent experiments on optical modulation allowing localization of condensates in a trap with well-controlled shape and dimensions, we study the quasi-one-dimensional (1D) motion of the BEC inmicrowires and report the corresponding Bogolyubov excitation spectrum. We show that in the 1D case the characteristic polariton-polariton interaction constant is expressed as g(1) = 3 lambda N/(2L(y)) (lambda is the 2D polariton-polariton interaction parameter in the cavity, N the number of the particles, and L-y the wire cavity width). We reveal some interesting features for 2D and 1D Bogolyubov spectra for both repulsive (lambda > 0) and attractive (lambda < 0) interactions.Fundação para a Ciência e a Tecnologia (FCT) - Portuguese Foundation for Science and Technology
Grants: PTDC-FIS-113199-2009, PEst-C/FIS/UI0607/2013CNPq, FAPESP, BrazilRussian Ministry of Education and Science
11.G34.31.006
Molecular fluorine chemistry in the early Universe
Some models of Big Bang nucleosynthesis suggest that very high baryon density
regions were formed in the early Universe, and generated the production of
heavy elements other than lithium such as fluorine F. We present a
comprehensive chemistry of fluorine in the post-recombination epoch.
Calculation of F, F- and HF abundances, as a function of redshift z, are
carried out. The main result is that the chemical conditions in the early
Universe can lead to the formation of HF. The final abundance of the diatomic
molecule HF is predicted to be close to 3.75 10(-17) when the initial abundance
of neutral fluorine F is 10(-15). These results indicate that molecules of
fluorine HF were already present during the dark age. This could have
implications on the evolution of proto-objects and on the anisotropies of
cosmic microwave background radiation. Hydride of fluorine HF may affect
enhancement of the emission line intensity from the proto-objects and could
produce spectral-spatial fluctuations.Comment: Accepted in Astronomy and Astrophysics, 7 pages, 2 figure
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