Are Young People's Educational Outcomes Linked to their Sense of Control?

This paper analyzes the link between young people's sense (locus) of control over their lives and their investments in education. We find that young people with a more internal locus of control have a higher probability of finishing secondary school and, conditional on completion, meeting the requirements to obtain a university entrance rank. Moreover, those with an internal locus of control who obtain a university entrance rank achieve somewhat higher rankings than do their peers who have a more external locus of control. Not surprisingly, there is a negative relationship between growing up in disadvantage and educational outcomes. However, this effect does not appear to operate indirectly by increasing the likelihood of having a more external locus of control. In particular, we find no significant relationship between family welfare history and young people's locus of control.locus of control, parental socio-economic background, education

Environmental volumetric criterion for green spaces calculus

Los espacios verdes y, en general, la vegetación utilizada para protección, son valorados, medidos y calculados por el área destinada a esa función más que por los elementos vegetales relacionados. Esto significa una simplificación excesiva que no aporta los criterios de cuantificación necesarios tanto para preservar el patrimonio natural existente como para elaborar proyectos de mejoramiento ambiental. En este trabajo se propone un concepto nuevo para la valoración de los elementos vegetales atendiendo a su influencia como mejoradores ambientales. Se determinan dos índices de valoración: el Índice de Vegetación Ambientalmente Activa por unidad de área utilizada y el Índice Ambiental Urbanístico. Ambos permiten cuantificar la importancia urbanística y ambiental de la vegetación. También se introduce un nuevo concepto en el cálculo de la necesidad de espacios verdes en proyectos urbanísticos y en áreas de amortiguación industriales, basado en el volumen vegetativo que debe existir en áreas que normalmente se destinan a espacios verdes.The green spaces and, in general, the protective vegetation, are valuated, measured and calculated by the area designated to that function, rather than by the related vegetal elements. This means that an excessive simplification is used, which does not apport cuantitative valoration criteria. These criteria is presently needed both in preserving natural patrimony, and in projecting tasks in environment improvement engineering. In this work, a new valoration concept for the vegetal elements is proposed, based on their influence as environment improvers. Valoration indexes are defined: such as the Environmentally Active Vegetation Index by utilized area unit, and the Urban Environment Index. These indexes allow for the quantitative evaluation of the urbanistic and environmental value of the vegetation. A new concept to calculate the need of green areas both in urbanistic and in industrial protection areas is also proposed. The concept is based on the vegetation volume needs in the areas usually designated for green spaces.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción VegetalFil: Barón, Jorge. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computador

Environmental Biotechnology Screening Cu and Cd tolerance in Salix species from North Morocco

Hydroponic culture has been used to compare copper and cadmium tolerance in five Salix species from North Morocco using different approaches. Measurements of growth parameters have been combined with those of some photosynthetic parameters. Tolerance index based either on root or shoot growth allowed to define Salix pedicelata and Salix purpurea as Cu and Cd-tolerant species, respectively. From the methodological point of view, the use of tolerance index based on aerial part growth, appeared mostadequate for the screening of metal tolerance in woody plants. On the other hand, no significant effect on chlorophyll content was observed under treatment with either Cu or Cd, in any of the Salix species analyzed. In vitro experiments with thylakoid membranes showed that the effects on the electron transport chain differ for each metal and species used. Furthermore, it seems that metal tolerance at the chloroplast level is distinct to that of the whole plant

Karst Hidrology oh Mallorca

Els aqüífers carstics de Mallorca resulten d'importancia essencial per a I'abastiment d'aigua de I'llla. Es poden distingir dos tipus d'aqüifers carstics: els desenvolupats en mater ial~do lomítics i calcaris del Jurassic inferior i els que es troben en els diposits tabulars del Mioce superior. Els primers representen materials fortament aixecats i estructurats on es presenta freqüentment una doble permeabilitat, que registra una circulació a través de grans cavitats ¡/o de petites fissures. Els aqüífers carstics del segon tipus s'estenen sobre diposits subhoritzontals, lleugerament aixecats i amb una intensa relació amb les oscil.lacions del nivel1 de la mar.Karstic aquifers of Mallorca are of vital importance for the water supply of the island. Two types have been distinguished: the first one corresponds to greatly structured and folded dolomites and limestones, early Jurassic in age, which usually develop a double permeability characterized by flows both through large karst conduits and through small fissures. The second type of karst aquifers develops in tabular upper Miocene deposits gently structured and uplifted, located in the coastal zones in southern Mallorc

Dynamics of the planktonic food web in Colgada Lake (Lagunas de Ruidera Natural Park)

In Colgada Lake, one of the 15 lakes belonging to Lagunas de Ruidera Natural Park, the components of the lineal food chain (phytoplankton and metazooplankton) and the microbial loop phytoplankton, metazooplankton, ciliates, autotrophic picoplankton, and bacterioplankton) were studied from June 2003 to December 2004 with a monthly sampling frequency. This lake has monomictic and mesotrophic characteristics and a mean depth of 8 m. Sixty-two species of the phytoplankton community, 27 species of metazooplankton community, and 12 species of ciliates were identified. Phytoplankton and metazooplankton integrated biomass followed seasonal patterns with higher values in summer, up to 105 mg WW/m2 and 2 × 104 mg WW/m2, respectively. Autotrophic picoplankton did not exceed 500 mg WW/m2. Microbial loop components did not show seasonality, and its biomass concentration fluctuated between 500-2500 mg WW/m2 for ciliates and 100- 2000 mg WW/m2 for bacterioplankton. Centric Bacillariophyceae, Cryptophyceae, and Dinophyceae represented most of the phytoplanktonic biomass throughout the studied period, although an increase of cyanobacteria was also observed. Cladocerans and calanoid copepods dominated during summer stratification, rotifers and cyclopoid copepods were present during the winter mixing period. The microbial loop biomass in relation to total planktonic biomass was higher in winter and spring 2004. Interannual changes in the presence of planktonic groups were observed in the different periods of the year: i) the algal composition included larger and non-edible species (Cyanobacteria, Dinophyceae), ii) a reduction in the clearance function by cladocerans was produced, which were substituted by a cyclopoid predator that iii) can feed on rotifers and ciliates, favouring in this way bacterioplankton and autotrophic pico-nanoplankton. This interannual variation could be related to the ongoing eutrophication process in the Lake. All of this may change the way the lake looks: if spring primary production is not strongly controlled by herbivory, this could threaten the annual recruitment of submerged macrophytes that significantly contribute to improve the water quality of the lake.En la laguna Colgada, una de las 15 lagunas que componen el Parque Natural de Las lagunas de Ruidera, se han estudiado los componentes de la red trófica planctónica (fitoplancton, metazooplancton, ciliados, picoplancton autotrófico -PPA- y bacterioplancton), desde junio de 2003 a diciembre de 2004, con una frecuencia de muestreo mensual. Esta laguna posee un carácter monomíctico y mesotrófico y una profundidad media de 8 m. Se identificaron 62 especies de la comunidad fitoplanctónica, 27 especies de la comunidad de metazooplancton y 12 especies de ciliados. La biomasa integrada de fitoplancton y metazooplancton mostró un patrón estacional con valores más elevados en verano, hasta 105 mg PF/m2 y 2 × 104 mg PF/m2, respectivamente. El PPA no superó los 500 mg PF/m2. Bacterias y ciliados no presentaron estacionalidad, y su concentración fluctuó entre 500-2500 mg PF/m2 en el caso de los ciliados y 100-2000 mg PF/m2 en el bacterioplancton. Poblaciones de Bacillariophyceae de tipo centrales, Cryptophyceae y Dinophyceae constituyeron la mayor parte de la biomasa fitoplanctónica durante todo el periodo de estudio, aunque se observó un incremento de cianobacterias. Cladóceros y copépodos calanoides fueron dominantes durante la estratificación estival, rotíferos y copépodos ciclopoides estaban presentes en la mezcla invernal. La biomasa relativa del bucle microbiano frente al total de biomasa planctónica fue superior en inverno y primavera de 2004. Se han observado cambios interanuales en la presencia de los grupos planctónicos de los diferentes periodos del año: i) la composición algal incluye especies más grandes y menos comestibles (Cyanobacteria, Dinophyceae), ii) se produce una reducción de la función de aclarado de los cladóceros que son sustituidos por un depredador ciclopoide que iii) se pue de alimentar de rotíferos y ciliados, favoreciendo así a las bacterias y el pico-nanoplancton autotrófico. Esta variación interanual podría estar relacionada con el proceso de eutrofización que está sufriendo la laguna. Todo ello puede llegar a cambiar el aspecto de la laguna: si la producción primaria en primavera no está fuertemente controlada por la herbivoría, se puede impedir el reclutamiento anual de los macrófitos sumergidos que contribuyen significativamente a mejorar la calidad de la aguas de esta laguna

Chassis design for an autonomous electric vehicle for the city of Cartagena de Indias (Elevated Autonomous Transport System-Caribbean railway) using finite elements and the Shell technique

SciVal Topics Metrics Abstract This document contains the chassis design for an autonomous electric vehicle. First, a fatigue failure analysis should be done to the underside of the chassis under fluctuating loads. Subsequently, the methodology of the shell technique or plate technique is applied to make the structural analysis by finite elements of the complete structure. The results show a satisfactory design that meets all the criteria used. © 2020 IEEE

Variabilidad espacial y temporal en la comunidad de cladóceros de la Ciénaga de Paredes (Santander, Colombia) a lo largo de un ciclo anual

En la Ciénaga de Paredes (73 · 45'-73· 49'W y 7·26'-7·29'N), ubicada en el Departamento de Santander (Colombia), se determinó la composición, la variación espacial y temporal de la estructura de la comunidad de cladóceros, con base en arrastres verticales con malla de 68 μm, en ocho estaciones de muestreo en un ciclo anual (febrero de 1998 a enero de 1999).Para evaluar la estructura, se utilizaron los números de Hill (N0, N1 y N2) y la equidad. El soporte del muestreo fue calculado con los estimadores Chao 1 y 2. La existencia de diferencias significativas de los números de Hill, la equidad, la densidad numérica, la columna de agua, el pH, el OD, y la temperatura, entre campañas y entre estaciones, se realizó a través de un ANDEVA. Las especies y morfoespecies encontradas (31) poseen distribución tropical, subtropical y cosmopolita; pertenecen generalmente a cuerpos de agua temporales, llanuras de inundación o ciénagas. Las mayores abundancias fueron registradas para Moina minuta, Moina cf. micrura, Diaphanosoma brevireme y Ceriodaphnia cornuta, las cuales representaron el 81.9 % del total de individuos colectados. Los resultados obtenidos por los estimadores de riqueza indican que si se aumentara el esfuerzo de muestreo con las técnicas utilizadas, no incrementaría el número de morfoespecies. Con respecto a la variación espacial de la estructura, la estación V presento mayor equidad, riqueza y diversidad, pero menor densidad numérica, esta condición muestra la diferencia de esta estación en comparación con las demás; su tendencia atípica es explicada ya que dicha estación se encuentra cerca del afluente principal de la Ciénaga (Quebrada La Gómez). En la variación temporal, la estructura de la comunidad de cladóceros cambió entre campañas de muestreo ya que la equidad y la riqueza presentaron diferencias significativas, que se evidencian en el cambio de la abundancia relativa de las morfoespecies, mas no en la abundancia de cladóceros. Esto es causado por las fluctuaciones de la precipitación y el alto de la columna de agua.In the Ciénaga de Paredes (73 · 45'-73· 49'W y 7·26'-7·29'N), located in the Department of Santander (Colombia), the composition, and the spatial and temporal variation of the cladoceran community structure was determined with samples taken with a 68 μm vertical-hauled net, at eight sampling stations in an annual cycle (February 1998 to January 1999). To evaluate the structure, Hill numbers (N0, N1 and N2) and evenness were used. The sampling support was calculated with the Chao 1 and 2 estimators. The existence of significant differences for Hill numbers, evenness, numeric density, water column, pH, OD, and temperature among field trips and among stations, was analysed through an ANOVA. The species and morphospecies found (31), had a tropical, subtropical, and cosmopolitan distribution; belonging to temporary water bodies, floodplains or "ciénagas". The highest abundances were registered for Moina minuta, Moina cf. micrura, Diaphanosoma brevireme and Ceriodaphnia cornuta, which represented 81.9 % of the total collected individuals. The results obtained with the richness estimates suggest that if the sampling effort were increased using the same techniques, the morphospecies' number would have not increased. With regard to the structure's spatial variation, the station V showed higher evenness, richness, and diversity, but lower numeric density; this condition shows the difference between this station and the other ones; ical trend is explained by this station being near to the main tributary of the "Ciénaga" ("Quebrada La Gómez").Regarding the temporal variation, the cladocerans' community structure changed between field trips, since the evenness and the richness showed significant differences, reflected by the variation in the relative abundance of the morphospecies but not in the cladocerans' abundance. This was caused by the fluctuations in rainfall and water level

Valence change of praseodymium in Pr0.5Ca0.5CoO3 investigated by x-ray absorption spectroscopy

X-ray absorption spectroscopy measurements in Pr0.5Ca0.5CoO3 were performed at the Pr M4,5, Pr L3, and Ca L2,3 absorption edges as a function of temperature below 300 K. Ca spectra show no changes down to 10 K while a noticeable thermally dependent evolution takes place at the Pr edges across the metal-insulator transition. Spectral changes are analyzed by different methods, including multiple scattering simulations, which provide quantitative details on an electron loss at Pr 4f orbitals. We conclude that in the insulating phase a fraction [15(+5)%] of Pr3+ undergoes a further oxidation to adopt a hybridized configuration composed of an admixture of atomic-like 4f1 states (Pr4+) and f- symmetry states on the O 2p valence band (Pr3+L states) indicative of a strong 4f- 2p interaction.Comment: 19 pages (.doc), 4 figures, Phys. Rev. B, in pres