Mineral profile grassland of Andropogon lateralis and Sorghastrum setosum (Gramineae) in Corrientes, Argentina

El objetivo de este trabajo fue determinar la composición florística y el aporte de minerales a la dieta animal para la producción de carne bovina de los pastizales de Andropogon lateralis Nees (PAL) y Sorghastrum setosun (Griseb.) Hitchc. (PSS), analizados mediante espectrometría ICP-AES en dos series de suelo de la provincia de Corrientes, Argentina. El mayor aporte de materia seca lo realizan A. lateralis y S. setosum. El aporte de leguminosas es bajo. El perfil de elementos minerales esenciales, probablemente esenciales y los de función incierta, cubren parcialmente los requerimientos del ganado bovino productor de carne, excepto para Mn. Las relaciones entre elementos, Ca/P, Na/K (mEq), Cu/Mo y Cu/Fe son aceptables. Las relaciones K/Mg, K/Ca+Mg (mEq) y Na/Mg (mEq) no son adecuadas, pues existe deficiencia de Mg.The goal of this work was to determine the floristic composition and the mineral contribution of Andropogon lateralis Nees (PAL) and Sorghastrum setosum (PSS) pastures, in the animal diet for the production of beef, analyzed by ICP-AES spectrometry in two series of soils from the Province of Corrientes, Argentina. The greatest contribution of dry raw matter is provided by A. lateralis and S. setosum. The contribution of legume is low. The profile of essential mineral elements, probably essential ones and of those of uncertain function, partially fulfill the meat producer cattle requirements. The elemental ratios Ca/P, Na/K (mEq), Cu/Mo and Cu/Fe, are acceptable. The K/Mg, K/Ca+Mg (mEq) and Na/Mg (mEq) ratios are not adequate, and there is Mg deficiency.Fil: Bernardis, Aldo C.. Universidad Nacional del Nordeste. Facultad de Ciencias AgrariasFil: Villafañe, Roxana. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Pellerano, Roberto G.. Universidad Nacional del NordesteFil: Marchevky, Eduardo. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química

Synergistic effects of UVR and simulated stratification on commensalistic phytoplankton–bacteria relationship in two optically contrasting oligotrophic Mediterranean lakes

An indirect effect of global warming is a reduction in the depth of the upper mixed layer (UML) causing organisms to be exposed to higher levels of ultraviolet (UVR, 280–400 nm) and photosynthetically active radiation (PAR, 400–700 nm). This can affect primary and bacterial production as well as the commensalistic phytoplankton–bacteria relationship. The combined effects of UVR and reduction in the depth of the UML were assessed on variables related to the metabolism of phytoplankton and bacteria, during in situ experiments performed with natural pico- and nanoplankton communities from two oligotrophic lakes with contrasting UVR transparency (high-UVR versus low-UVR waters) of southern Spain. The negative UVR effects on epilimnetic primary production (PP) and on heterotrophic bacterial production (HBP), intensified under increased stratification, were higher in the low-UVR than in the high-UVR lake, and stronger on the phytoplanktonic than on the heterotrophic bacterial communities. Under UVR and increased stratification, the commensalistic phytoplankton–bacteria relationship was strengthened in the high-UVR lake where excretion of organic carbon (EOC) rates exceeded the bacterial carbon demand (BCD; i.e., BCD : EOC(%) ratio 100). The greater UVR damage to phytoplankton and bacteria and the weakening of their commensalistic interaction found in the low-UVR lake indicates that these ecosystems would be especially vulnerable to UVR and increased stratification as stressors related to global climate change. Thus, our findings may have important implications for the carbon cycle in oligotrophic lakes of the Mediterranean region.This study was supported by the Ministerio Español de Medio Ambiente, Rural y Marino (PN2009/067), Ciencia e Innovación (CGL2011-23681), Junta de Andalucía (Excelencia CVI-02598 and P09-RNM-5376), Consejo Nacional de Investigaciones Científicas y Técnicas – CONICET (PIP no. 112-201001-00228), and Fundación Playa Unión. G. Herrera and C. Durán were supported by a Formación de Profesorado Universitario grant from the Spanish government. The authors are indebted to the staff of Sierra Nevada National Park and Lagunas de Ruidera Natural Park for permission to work, to E. Jiménez-Coll for the bacterial production analysis, and to D. Nesbitt for writing assistance in English

Direct and indirect effects of vertical mixing, nutrients and ultraviolet radiation on the bacterioplankton metabolism in high-mountain lakes from southern Europe

As a consequence of global change, modifications in the interaction among abiotic stressors on aquatic ecosystems have been predicted. Among other factors, UVR transparency, nutrient inputs and shallower epilimnetic layers could alter the trophic links in the microbial food web. Currently, there are some evidences of higher sensitiveness of aquatic microbial organisms to UVR in opaque lakes. Our aim was to assess the interactive direct and indirect effects of UVR (through the excretion of organic carbon – EOC – by algae), mixing regime and nutrient input on bacterial metabolism. We performed in situ short-term experiments under the following treatments: full sunlight (UVR + PAR, >280 nm) vs. UVR exclusion (PAR only, >400 nm); ambient vs. nutrient addition (phosphorus (P; 30 μg PL−1) and nitrogen (N; up to final N : P molar ratio of 31)); and static vs. mixed regime. The experiments were conducted in three high-mountain lakes of Spain: Enol [LE], Las Yeguas [LY] and La Caldera [LC] which had contrasting UVR transparency characteristics (opaque (LE) vs. clear lakes (LY and LC)). Under ambient nutrient conditions and static regimes, UVR exerted a stimulatory effect on heterotrophic bacterial production (HBP) in the opaque lake but not in the clear ones. Under UVR, vertical mixing and nutrient addition HBP values were lower than under the static and ambient nutrient conditions, and the stimulatory effect that UVR exerted on HBP in the opaque lake disappeared. By contrast, vertical mixing and nutrient addition increased HBP values in the clear lakes, highlighting for a photoinhibitory effect of UVR on HBP. Mixed regime and nutrient addition resulted in negative effects of UVR on HBP more in the opaque than in the clear lakes. Moreover, in the opaque lake, bacterial respiration (BR) increased and EOC did not support the bacterial carbon demand (BCD). In contrast, bacterial metabolic costs did not increase in the clear lakes and the increased nutrient availability even led to higher HBP. Consequently, EOC satisfied BCD in the clear lakes, particularly in the clearest one [LC]. Our results suggest that the higher vulnerability of bacteria to the damaging effects of UVR may be particularly accentuated in the opaque lakes and further recognizes the relevance of light exposure history and biotic interactions on bacterioplankton metabolism when coping with fluctuating radiation and nutrient inputs.Fil: Durán, C.. Universidad de Granada; EspañaFil: Medina Sánchez, J. M.. Universidad de Granada; EspañaFil: Herrera, G.. Universidad de Granada; EspañaFil: Villar Argaiz , M.. Universidad de Granada; EspañaFil: Villafañe, Virginia Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Helbling, Eduardo Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Carrillo, P.. Universidad de Granada; Españ

Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients) that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR) than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada), used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a) solar radiation: UVR + PAR (280–700 nm) versus PAR (photosynthetically active radiation) alone (400–700 nm); (b) nutrient addition (phosphorus (P) and nitrogen (N)): ambient versus addition (P to reach to a final concentration of 30 μg P L−1, and N to reach N:P molar ratio of 31); and (c) mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min−1, total of 10 cycles)) versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC) from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The opposite occurs in clear lakes where antagonistic effects were determined, with mixing partially counteracting the negative effects of UVR. Nutrient input, mimicking atmospheric pulses from Saharan dust, reversed this effect and clear lakes became more inhibited during mixing, while opaque lakes benefited from the fluctuating irradiance regime. These climate change related scenarios of nutrient input and increased mixing, would not only affect photosynthesis and production in lakes, but might also further influence the microbial loop and trophic interactions via enhanced EOC under fluctuating UVR exposure.This work was supported by Ministerio Español de Medio Ambiente, Rural y Marino (PN2009/067) and Ciencia e Innovación (GLC2008-01127/BOS and CGL2011-23681), Junta de Andalucía (Excelencia CVI-02598), Agencia Nacional de Promoción Científica y Tecnológica (PICT 2007-1651) and Fundación Playa Unión; GH and CD were supported by the Spanish Government – Formación de Profesorado Universitario Grant

La Evaluación Del Trastorno Por Estrés Postraumático: Aproximación A Las Propiedades Psicométricas De La Escala De Trauma De Davidson

Debido a la alta comorbilidad que presenta el Trastorno por Estrés Postraumático (TEPT), se considera relevante hacer una aproximación a las propiedades psicométricas de la Escala de Trauma de Davidson-DTS, que indaga los síntomas del trastorno, para determinar si la misma es un instrumento válido de diagnóstico. Para ello se tomaron dos muestras de sujetos entre 18 y 20 años, una conformada por estudiantes de Psicología de la UNC y otra por estudiantes de diferentes instituciones educativas de Río Tercero. Se administraron cinco instrumentos de autoinforme, dos evalúan síntomas de TEPT (DTS e IES-R), uno de depresión (Beck), un cuestionario de acontecimientos traumáticos y los STAIs, para síntomas de ansiedad. Como conclusión final la Escala de Trauma de Davidson cuenta con propiedades psicométricas aceptables para evaluar el Trastorno por Estrés Postraumático

Perfil mineral en los pastizales de Andropogon lateralis y Sorghastrum setosum (Gramineae) en Corrientes, Argentina

The goal of this work was to determine the floristic composition and the mineral contribution of Andropogon lateralis Nees (PAL) and Sorghastrum setosum (PSS) pastures, in the animal diet for the production of beef, analyzed by ICP-AES spectrometry in two series of soils from the Province of Corrientes, Argentina. The greatest contribution of dry raw matter is provided by A. lateralis and S. setosum. The contribution of legume is low. The profile of essential mineral elements, probably essential ones and of those of uncertain function, partially fulfill the meat producer cattle requirements. The elemental ratios Ca/P, Na/K (mEq), Cu/Mo and Cu/Fe, are acceptable. The K/Mg, K/Ca+Mg (mEq) and Na/Mg (mEq) ratios are not adequate, and there is Mg deficiency.El objetivo de este trabajo fue determinar la composición florística y el aporte de minerales a la dieta animal para la producción de carne bovina de los pastizales de Andropogon lateralis Nees (PAL) y Sorghastrum setosun (Griseb.) Hitchc. (PSS), analizados mediante espectrometría ICP-AES en dos series de suelo de la provincia de Corrientes, Argentina. El mayor aporte de materia seca lo realizan A. lateralis y S. setosum. El aporte de leguminosas es bajo. El perfil de elementos minerales esenciales, probablemente esenciales y los de función incierta, cubren parcialmente los requerimientos del ganado bovino productor de carne, excepto para Mn. Las relaciones entre elementos, Ca/P, Na/K (mEq), Cu/Mo y Cu/Fe son aceptables. Las relaciones K/Mg, K/Ca+Mg (mEq) y Na/Mg (mEq) no son adecuadas, pues existe deficiencia de Mg

Funcionamiento de los lagos someros mediterráneos.

P. 2-12Aún existe un importante desconocimiento sobre el funcionamiento de las lagunas o lagos someros mediterráneos. Ante la carencia de estudios propios de estos ambientes, la abundancia de estudios en el norte de Europa ha supuesto una generalización de procesos y características potencialmente aplicables a nuestros lagos. Sin embargo, la comparación de los distintos estudios en ambas zonas demuestra que las lagunas mediterráneas presentan peculiaridades únicas y un funcionamiento significativamente diferente. Tamaños más pequeños, mayor aislamiento, fuertes oscilaciones de la lámina de agua, mayor productividad y ausencia de ciertos grupos tróficos, entre otras, son características distintivas de nuestros sistemas. Estas características tienen importantes implicaciones en la dinámica de sus poblaciones y en la estructura y funcionamiento de las comunidadesS

Optoelectronic forces with quantum wells for cavity optomechanics in GaAs/AlAs semiconductor microcavities

Radiation pressure, electrostriction, and photothermal forces have been investigated to evidence backaction, nonlinearities, and quantum phenomena in cavity optomechanics. We show here through a detailed study of the relative intensity of the cavity mechanical modes observed when exciting with pulsed lasers close to the GaAs optical gap that optoelectronic forces involving real carrier excitation and deformation potential interaction are the strongest mechanism of light-to-sound transduction in semiconductor GaAs/AlAs distributed Bragg reflector optomechanical resonators. We demonstrate that the ultrafast spatial redistribution of the photoexcited carriers in microcavities with massive GaAs spacers leads to an enhanced coupling to the fundamental 20-GHz vertically polarized mechanical breathing mode. The carrier diffusion along the growth axis of the device can be enhanced by increasing the laser power, or limited by embedding GaAs quantum wells in the cavity spacer, a strategy used here to prove and engineer the optoelectronic forces in phonon generation with real carriers. The wavelength dependence of the observed phenomena provide further proof of the role of optoelectronic forces. The optical forces associated with the different intervening mechanisms and their relevance for dynamical backaction in optomechanics are evaluated using finite-element methods. The results presented open the path to the study of hitherto seldom investigated dynamical backaction in optomechanical solid-state resonators in the presence of optoelectronic forces.Fil: Villafañe, Viviana Daniela. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Sesin, Pablo Ezequiel. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Soubelet, Pedro Ignacio. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Anguiano, Sebastian. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Bruchhausen, Axel Emerico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Rozas, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Gomez Carbonell, C.. Université Paris Sud; FranciaFil: Lemaître, A.. Université Paris Sud; FranciaFil: Fainstein, Alejandro. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Do UK universities communicate their brands effectively through their websites?

This paper attempts to explore the effectiveness of UK universities’ websites. The area of branding in higher education has received increasing academic investigation, but little work has researched how universities demonstrate their brand promises through their websites. The quest to differentiate through branding can be challenging in the university context, however. It is argued that those institutions that have a strong distinctive image will be in a better position to face a changing future. Employing a multistage methodology, the web pages of twenty UK universities were investigated by using a combination of content and multivariable analysis. Results indicated ‘traditional values’ such as teaching and research were often well communicated in terms of online brand but ‘emotional values’ like social responsibility and the universities’ environments were less consistently communicated, despite their increased topicality. It is therefore suggested that emotional values may offer a basis for possible future online differentiation