Electrochemical synthesis of peroxomonophosphate using boron-doped diamond anodes

A new method for the synthesis of peroxomonophosphate, based on the use of boron-doped diamond electrodes, is described. The amount of oxidant electrogenerated depends on the characteristics of the supporting media (pH and solute concentration) and on the operating conditions (temperature and current density). Results show that the pH, between values of 1 and 5, does not influence either the electrosynthesis of peroxomonophosphate or the chemical stability of the oxidant generated. Conversely, low temperatures are required during the electrosynthesis process to minimize the thermal decomposition of peroxomonophosphate and to guarantee significant oxidant concentration. In addition, a marked influence of both the current density and the initial substrate is observed. This observation can be explained in terms of the contribution of hydroxyl radicals in the oxidation mechanisms that occur on diamond surfaces. In the assays carried out below the water oxidation potential, the generation of hydroxyl radicals did not take place. In these cases, peroxomonophosphate generation occurs through a direct electron transfer and, therefore, at these low current densities lower concentrations are obtained. On the other hand, at higher potentials both direct and hydroxyl radical-mediated mechanisms contribute to the oxidant generation and the process is more efficient. In the same way, the contribution of hydroxyl radicals may also help to explain the significant influence of the substrate concentration. Thus, the coexistence of both phosphate and hydroxyl radicals is required to ensure the generation of significant amounts of peroxomonophosphoric acid

Absence of charge backscattering in the nonequilibrium current of normal-superconductor structures

We study the nonequilibrium transport properties of a normal-superconductor-normal structure, focussing on the effect of adding an impurity in the superconducting region. Current conservation requires the superfluid velocity to be nonzero, causing a distortion of the quasiparticle dispersion relation within the superconductor. For weakly reflecting interfaces we find a regime of intermediate voltages in which Andreev transmission is the only permitted mechanism for quasiparticles to enter the superconductor. Impurities in the superconductor can only cause Andreev reflection of these quasiparticles and thus cannot degrade the current. At higher voltages, a state of gapless superconductivity develops which is sensitive to the presence of impurities.Comment: Latex file, 11 pages, 2 figures available upon request [email protected], to be published in Journal of Physics: Condensed Matte

Association Between Type 2 Diabetes Mellitus and the Presence of Myocardial Ischemia among Filipino Patients with Stress Myocardial Perfusion Scintigraphy

Background: Type 2 DM patients usually had poor prognosis for CAD. MPS with SPECT has been extensively used in CAD detection and it’s application among type 2 DM population is still under study with promising result. In the Philippines, there are no current available data regarding this matter. Methodology: This was a cross sectional analytical study of randomly selected Filipino patients without previous cardiac events in whom MPS using Thallium-201 were performed over a 24-month period. Association of myocardial ischemia was compared using logistic regression analysis based on total summed stress score (SSS) values. Results: Total of 208 patients (104 type 2 DM and 104 non-type 2 DM) who underwent stress or pharmacologic MPS using Thallium-201 were included in the study. Majority of the subjects were male. Abnormal 2D echo result and lower EF were significantly present among type 2 DM group (p = 0.044, 0.0005). Hypertension was more prominent among the list of co-morbidities and has significant relationship with type 2 DM group (p = 0.025). The distribution of myocardial ischemia among type 2 DM group with insignificant, mildly abnormal, and moderate to severely abnormal; were 60.6%, 12.5%, and 26.9%, respectively. The presence of having significant CAD (SSS>3) was associated with the type 2 DM group with odds ratio of 2.57 (95% CI: 1.38-4.78, p = 0.003). Conclusion: The current study has shown that Filipino type 2 DM patients without previous cardiac events are likely to have significant and more severe scintigraphic evidence of CAD than their non-type 2 DM counterpart. Keywords: coronary artery disease, Filipino type 2 diabetic patients, myocardial perfusion scintigraphy, myocardial ischemia, summed stress scor

Heurísticas y sesgos en el razonamiento probabilístico de los estudiantes de secundaria

En este trabajo se analizan las respuestas de 277 estudiantes de enseñanza secundaria a 8 ítems usados en estudios clásicos de razonamiento probabilístico (representatividad, sesgo de equiprobabilidad y enfoque en el resultado aislado). El estudio tuvo como fin comparar el razonamiento probabilístico en dos niveles de estudiantes de secundaria (14 y 18 años). Como resultado, observamos pocas diferencias, después que el segundo grupo recibió instrucción formal en probabilidad. Finalmente, usamos el análisis multivariante para evaluar la dependencia entre los tipos de heurísticas y sesgos detectados

Self-consistent scattering description of transport in normal-superconductor structures

We present a scattering description of transport in several normal-superconductor structures. We show that the related requirements of self-consistency and current conservation introduce qualitative changes in the transport behavior when the current in the superconductor is not negligible. The energy thresholds for quasiparticle propagation in the superconductor are sensitive to the existence of condensate flow ($v_s\neq 0$). This dependence is responsible for a rich variety of transport regimes, including a voltage range in which only Andreev transmission is possible at the interfaces, and a state of gapless superconductivity which may survive up to high voltages if temperature is low. The two main effects of current conservation are a shift towards lower voltages of the first peak in the differential conductance and an enhancement of current caused by the greater availability of charge transmitting scattering channels.Comment: 31 pages, 10 PS figures, Latex file, psfig.sty file is added. To appear in Phys. Rev. B (Jan 97

Transcriptomic analysis of tomato carpel development reveals alterations in ethylene and gibberellin synthesis during pat3/pat4 parthenocarpic fruit set

<p>Abstract</p> <p>Background</p> <p>Tomato fruit set is a key process that has a great economic impact on crop production. We employed the Affymetrix GeneChip Tomato Genome Array to compare the transcriptome of a non-parthenocarpic line, UC82, with that of the parthenocarpic line RP75/59 (<it>pat3/pat4 </it>mutant). We analyzed the transcriptome under normal conditions as well as with forced parthenocarpic development in RP75/59, emasculating the flowers 2 days before anthesis. This analysis helps to understand the fruit set in tomato.</p> <p>Results</p> <p>Differentially expressed genes were extracted with maSigPro, which is designed for the analysis of single and multiseries time course microarray experiments. 2842 genes showed changes throughout normal carpel development and fruit set. Most of them showed a change of expression at or after anthesis. The main differences between lines were concentrated at the anthesis stage. We found 758 genes differentially expressed in parthenocarpic fruit set. Among these genes we detected cell cycle-related genes that were still activated at anthesis in the parthenocarpic line, which shows the lack of arrest in the parthenocarpic line at anthesis. Key genes for the synthesis of gibberellins and ethylene, which were up-regulated in the parthenocarpic line were also detected.</p> <p>Conclusion</p> <p>Comparisons between array experiments determined that anthesis was the most different stage and the key point at which most of the genes were modulated. In the parthenocarpic line, anthesis seemed to be a short transitional stage to fruit set. In this line, the high GAs contends leads to the development of a parthenocarpic fruit, and ethylene may mimic pollination signals, inducing auxin synthesis in the ovary and the development of a jelly fruit.</p

THE RELATIONSHIP BETWEEN LEVEL OF EDUCATION, ORGANIZATIONAL COMMITMENT AND JOB SATISFACTION: AN ANALYSIS IN HOTEL ESTABLISHMENTS IN ANDALUSIA (SPAIN)

Nisu svi zaposlenici sposobni generirati vještine i resurse kojima bi se ostvarila organizacijska produktivnost. Samo su kvalificirani ljudski resursi (HR), prepo¬znati i odani politici tvrtke, dio organizacijskih kompetencija. Stoga su čimbenici zadovoljstva zapo¬slenika radom te predanost tvrtki dvije ključne varijable koje moramo analizirati kako bismo ispravno procijenili i pravilno upravljali ljudskim kapitalom tvrtke. Posebno se velika važnost pridaje vrijed¬nosti obrazovanja zaposlenika u svjetlu konkurentnosti turizma, što je u skladu s pretpostavkom kako stupanj obrazovanja zaposlenika izravno utječe na kvalitetu turističkih usluga. Cilj je ovog članka analizirati zadovoljstvo radnim mjestom i organizacijske obveze zaposlenika hotelskih kuća u Andaluziji (Španjolska), destinaciji čija je nesumnjiva konkurentska važnost u turi¬zmu neupitna. Pronađene su evidentne razlike u stupnju obrazovanja zaposlenika, tako da rezultati svakako ohrabruju odjele upravljanja ljudskim resursima na identifikaciju, održavanje i razvoj resursa i potencijalnih sposobnosti njihovog ljudskog kapitala.Not all employees are capable of generating skills and resources that may result in organizational productivity. Only qualified Human Resources, identified and committed to the company policy, are a part of the organization\u27s competences. Therefore, elements like the worker\u27s job satisfaction or the organizational commitment are two fundamental variables that need to be analyzed for the measurement and correct management of the company\u27s human capital. Further¬more, the importance that the value of the workers\u27 education presents towards competitiveness in tourism is highlighted since it is assumed that staff education is directly related to the quality of tourist service. The purpose of this paper is to analyze the relationship among educational level, job satisfaction, and organizational commitment of the employees of the hotel establishments in Andalusia (Spain), a destination of undeniable competitive significance in tourism. Evident differences were found among the level of education of workers, so the results have to encourage the human resources management to identify, maintain, and develop the resources and potential capabilities of their human capital

Voltage Stability Analysis of Grid-Connected Wind Farms with FACTS: Static and Dynamic Analysis

Recently, analysis of some major blackouts and failures of power system shows that voltage instability problem has been one of the main reasons of these disturbances and networks collapse. In this paper, a systematic approach to voltage stability analysis using various techniques for the IEEE 14-bus case study, is presented. Static analysis is used to analyze the voltage stability of the system under study, whilst the dynamic analysis is used to evaluate the performance of compensators. The static techniques used are Power Flow, V–P curve analysis, and Q–V modal analysis. In this study, Flexible Alternating Current Transmission system (FACTS) devices- namely, Static Synchronous Compensators (STATCOMs) and Static Var Compensators (SVCs) - are used as reactive power compensators, taking into account maintaining the violated voltage magnitudes of the weak buses within the acceptable limits defined in ANSI C84.1. Simulation results validate that both the STATCOMs and the SVCs can be effectively used to enhance the static voltage stability and increasing network loadability margin. Additionally, based on the dynamic analysis results, it has been shown that STATCOMs have superior performance, in dynamic voltage stability enhancement, compared to SVCs

Factors explaining the adoption of risk management instruments in mediterranean irrigated agriculture

Agriculture is highly impacted by different sources of risk. There is a wide variety of management instruments that farmers can use to cover these risks. The objective of this paper is to analyze the explanatory variables for the simultaneous adoption of a large set of risk management instruments. The main innovation is the methodological approach: first, we apply a hierarchical cluster analysis to identify the groups of instruments whose adoption is correlated; second, we use multivariate probit models to analyze the influence of different factors on the simultaneous adoption of the instruments included in each cluster. Explanatory variables capture farmers’ socio-demographic features, perception of risks, risk aversion and subjective perception of past risk experience; farms’ technical-economic characteristics; and perception of local-level climate change. The results show that there are significant differences in the variables influencing the adoption of the risk management instruments. The findings provide useful information to support the decision-making process for three main stakeholders: farmers (optimal choice over the joint use of instruments), providers of agricultural risk management instruments (e.g., the design of new combinations of risk management instruments better targeted to distinct profiles of farmers), and policymakers (policy strategies aiming to promote better risk management within the agricultural sector)