Probing the reactivity of a 2,2′-bipyridyl-3,3′-bis-imine ligand by X-ray crystallography

The reactivity of a Schiff-base bis-imine ligand 3 is probed by X-ray diffraction studies. Its susceptibility to hydrolysis, oxidation and nucleophilic addition reactions is demonstrated by the isolation of the methanol adduct 4 and two diazapene heterocycles 5 and 6. This reactivity is also reflected in the molecular structures of two coordination complexes isolated by the reaction of 3 with MIJhfac)2 salts, to afford [Cu(5)-(hfac)(tfa)] (8) and [Zn(6)(hfac)2] (9)

El éxito lleva al éxito, especialmente cuando la autoeficacia se relaciona con una atribución interna de causalidad

Taking the Social Cognitive Theory by Albert Bandura as its starting point, this paper tests the hypothesis that academic self-efficacy influences future academic success through the differential impact of internal and external attribution of past success. Structural Equation Modelling performed with data from a longitudinal sample of 527 university students provides strong evidence supporting the research model. These findings show that past academic success has a positive influence on academic self-efficacy (p < .001) and on future academic success (p < .001). Two processes can then occur: (1) when self-efficacy is related with an internal attribution (p < .001) it has a positive impact on future academic success over time (p < .001); (2) when self-efficacy is related with an external attribution (p < .001) it has a negative impact on future academic success (p < .05). Theoretical and practical implications, as well as its limitations and future research, are discussed.Considerando la Teoría Cognitiva Social de Albert Bandura, el presente trabajo pone a prueba la hipótesis de que la autoeficacia académica influye en el éxito académico futuro a través del impacto diferencial de la atribución interna y externa de los éxitos pasados. Modelos de Ecuaciones Estructurales en una muestra longitudinal de 527 estudiantes universitarios apoyan el modelo de investigación. Estos resultados muestran que el éxito académico pasado tiene una influencia positiva sobre la autoeficacia académica (p < .001) y sobre el éxito académico futuro (p < .001). Dos procesos pueden entonces ocurrir: (1) cuando la autoeficacia se relaciona con una atribución interna (p < .001) se muestra un impacto positivo sobre el éxito académico futuro a lo largo del tiempo (p < .001); (2) cuando la autoeficacia se relaciona con una atribución externa (p < .001) el impacto sobre el éxito académico futuro es negativo (p < .05). Se discuten las implicaciones de los resultados, sus limitaciones e investigación futura

The Automated Root Exudate System (ARES): a method to apply solutes at regular intervals to soils in the field.

Root exudation is a key component of nutrient and carbon dynamics in terrestrial ecosystems. Exudation rates vary widely by plant species and environmental conditions, but our understanding of how root exudates affect soil functioning is incomplete, in part because there are few viable methods to manipulate root exudates in situ. To address this, we devised the Automated Root Exudate System (ARES), which simulates increased root exudation by applying small amounts of labile solutes at regular intervals in the field. The ARES is a gravity-fed drip irrigation system comprising a reservoir bottle connected via a timer to a micro-hose irrigation grid covering c. 1 m2; 24 drip-tips are inserted into the soil to 4-cm depth to apply solutions into the rooting zone. We installed two ARES subplots within existing litter removal and control plots in a temperate deciduous woodland. We applied either an artificial root exudate solution (RE) or a procedural control solution (CP) to each subplot for 1 min day-1 during two growing seasons. To investigate the influence of root exudation on soil carbon dynamics, we measured soil respiration monthly and soil microbial biomass at the end of each growing season. The ARES applied the solutions at a rate of c. 2 L m-2 week-1 without significantly increasing soil water content. The application of RE solution had a clear effect on soil carbon dynamics, but the response varied by litter treatment. Across two growing seasons, soil respiration was 25% higher in RE compared to CP subplots in the litter removal treatment, but not in the control plots. By contrast, we observed a significant increase in microbial biomass carbon (33%) and nitrogen (26%) in RE subplots in the control litter treatment. The ARES is an effective, low-cost method to apply experimental solutions directly into the rooting zone in the field. The installation of the systems entails minimal disturbance to the soil and little maintenance is required. Although we used ARES to apply root exudate solution, the method can be used to apply many other treatments involving solute inputs at regular intervals in a wide range of ecosystems

Flow colectivo en equipos de trabajo que utilizan tecnologías

Decenes Jornades de Foment de la Investigació de la FCHS (Any 2004-2005)Cada vez más se está otorgando una mayor importancia a la capacidad de las personas para trabajar en equipo, tanto a nivel académico como a nivel organizacional. Este hecho remarca la necesidad de investigar acerca de cómo organizar y cómo optimizar ese trabajo en equipo. La presente investigación se encuadra desde el contexto de la Psicología Organizacional Positiva, donde cobra sentido el concepto de ‘flow colectivo’. El Flow es una “experiencia óptima extremadamente disfrutada. Se experimenta total concentración y disfrute con un alto interés por la actividad en si misma” (Moneta y Csikszentmihalyi, 1996). Esta experiencia puede aparecer tanto en actividades de ocio como en contextos laborales, y es en los contextos laborales donde se persigue estudiar el flow en equipos de trabajo. Además existen estudios (Chen, Wigand y Nilan, 2000; Trevino y Webster, 1992) en los que se ha encontrado muy relacionado el uso de las Tecnologías de la Información y Comunicación al hecho de experimentar flow. Así pues el objetivo del presente estudio es analizar la existencia de diferencias significativas en la experiencia de flow (absorción, interés intrínseco, disfrute) a través de un estudio experimental longitudinal, en una muestra de 100 estudiantes de la Universitat Jaume I, evaluando las dimensiones de flow a nivel colectivo, ya que los estudiantes realizaron tres tareas a nivel grupal. Así mismo, se comparan dos condiciones: uso- no uso de la tecnología en la realización de la tarea (grupos que realizaron las tareas utilizando el chat vs grupos que realizaron las tareas cara a cara). Por otro lado, también se estudia la influencia del control del tiempo en la realización de las tareas (grupos con la presión temporal vs grupos sin presión temporal). Los resultados muestran que no hay diferencias significativas en las tres variables del flow en cuanto al uso o no uso de la tecnología. Sin embargo, si observamos diferencias en cuanto a la presión temporal (tan sólo en las tareas 2 y 3) ya que los grupos que tenían control de tiempo parece ser que tienen más probabilidades de experimentar flow colectivo. Conclusiones e implicaciones teóricas y prácticas se desarrollan en el estudio

Quantitative assessment of energy and resource recovery in wastewater treatment plants based on plant-wide simulations.

The growing development of technologies and processes for resource treatment and recovery is offering endless possibilities for creating new plant-wide configurations or modifying existing ones. However, the configurations’ complexity, the interrelation between technologies and the influent characteristics turn decision-making into a complex or unobvious process. In this frame, the Plant-Wide Modelling (PWM) library presented in this paper allows a thorough, comprehensive and refined analysis of different plant configurations that are basic aspects in decision-making from an energy and resource recovery perspective. In order to demonstrate the potential of the library and the need to run simulation analyses, this paper carries out a comparative analysis of WWTPs, from a techno-economic point of view. The selected layouts were (1) a conventional WWTP based on a modified version of the Benchmark Simulation Model No. 2, (2) an upgraded or retrofitted WWTP, and (3) a new Wastewater Resource Recovery Facilities (WRRF) concept denominated as C/N/P decoupling WWTP. The study was based on a preliminary analysis of the organic matter and nutrient energy use and recovery options, a comprehensive mass and energy flux distribution analysis in each configuration in order to compare and identify areas for improvement, and a cost analysis of each plant for different influent COD/TN/TP ratios. Analysing the plants from a standpoint of resources and energy utilization, a low utilization of the energy content of the components could be observed in all configurations. In the conventional plant, the COD used to produce biogas was around 29%, the upgraded plant was around 36%, and 34% in the C/N/P decoupling WWTP. With regard to the self-sufficiency of plants, achieving self-sufficiency was not possible in the conventional plant, in the upgraded plant it depended on the influent C/N ratio, and in the C/N/P decoupling WWTP layout self-sufficiency was feasible for almost all influents, especially at high COD concentrations. The plant layouts proposed in this paper are just a sample of the possibilities offered by current technologies. Even so, the library presented here is generic and can be used to construct any other plant layout, provided that a model is available

The impact of health status and human capital formation on regional performance: Empirical evidence

The purpose of this paper is to analyze the impact of health on growth, assuming that it is a fundamental component of the human capital of a region along with education. Various measures of population health status are used, together with a health index generated by Principal Component Analysis. Potential endogeneity between health and growth is controlled for using instrumental variable regressions and dynamic panel data. The results show a positive effect of a change in health status on regional output and a negative effect of proxy variables for health limitations on regional performance. This corroborates the importance of investing in health along with education with the aim of improving not only the well-being of individuals but the human capital and growth of a region

Estimating the New Keynesian Phillips Curve: A Vertical Production Chain Approach

It has become customary to estimate the New Keynesian Phillips Curve (NKPC) with GMM using a large instrument set that includes lags of variables that are ad hoc to the model. Researchers have also conventionally used real unit labor cost (RULC) as the proxy for real marginal cost, even though it is difficult to support its significance. This paper introduces a new proxy for the real marginal cost term as well as a new instrument set, both of which are based on the micro foundations of the vertical chain of production. I find that the new proxy, based on input prices as opposed to wages, provides a more robust and significant fit to the model. Instruments that are based on the vertical chain of production appear to be both more valid and relevant towards the model

Inefficiency in the German Mechanical Engineering Sector

This paper aims to examine the relative efficiency of German engineering firms using a sample of roughly 23,000 observations between 1995 and 2004. As these firms had been successful in the examination period in terms of output- and export-growth, it is expected that a majority of firms is operating quite efficiently and that the density of efficiency scores is skewed to the left. Moreover, as the German engineering industry is dominated by medium sized firms, the question arises whether these firms are the most efficient ones. Finally an increasing efficiency gap between size classes over time is important since that would be a signal for a structural problem within the industry. The analysis - using recently developed DEA methods like bootstrapping or outlier detection - contradicts the two first expectations. The firms proved to operate quite inefficiently with an overall mean of 0.69, and efficiency differs significantly with firm size whereas medium sized firms being on average the least efficient ones. When looking at changes in efficiency over time, we find a decreasing efficiency gap between size classes

Tuning chelation by the surfactant-like peptide A6H using predetermined pH values

We examine the self-assembly of a peptide A6H comprising a hexa-alanine sequence A6 with a histidine (H) “head group”, which chelates Zn2+ cations. We study the self assembly of A6H and binding of Zn2+ ions in ZnCl2 solutions, under acidic and neutral conditions. A6H self-assembles into nanotapes held together by a β-sheet structure in acidic aqueous solutions. By dissolving A6H in acidic ZnCl2 solutions, the carbonyl oxygen atoms in A6H chelate the Zn2+ ions and allow for β-sheet formation at lower concentrations, consequently reducing the onset concentration for nanotape formation. A6H mixed with water or ZnCl2 solutions under neutral conditions produces short sheets or pseudocrystalline tapes, respectively. The imidazole ring of A6H chelates Zn2+ ions in neutral solutions. The internal structure of nanosheets and pseudocrystalline sheets in neutral solutions is similar to the internal structure of A6H nanotapes in acidic solutions. Our results show that it is possible to induce dramatic changes in the self-assembly and chelation sites of A6H by changing the pH of the solution. However, it is likely that the amphiphilic nature of A6H determines the internal structure of the self-assembled aggregates independent from changes in chelation

Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons. Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II. Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers. Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most