The Magnetic Field of the H~II Region NGC 6334A

We have studied the polarization characteristics and Faraday rotation of the extragalactic radio source J17204$-$3554, that appears projected on the north lobe of the galactic H II region NGC 6334A. From observations made with the Very Large Array at 6.0 and 3.6 cm in three different epochs (1994, 1997, and 2006), we estimate a rotation measure of +5100$\pm$900 rad m$^{-2}$ for the extragalactic source. This large rotation measure implies a line-of-sight average magnetic field of $B_\parallel \simeq +36\pm6$ $\mu$G, the largest obtained by this method for an H II region. NGC 6334A is significantly denser than other H II regions studied and this larger magnetic field is expected on the grounds of magnetic flux conservation. The ratio of thermal to magnetic pressure is $\sim$5, in the range of values determined for more diffuse H II regions.Comment: 5 pages, 0 figure

Modeling of the hydrogen Lyman lines in solar flares

The hydrogen Lyman lines (91.2 nm < λ < 121.6 nm) are significant contributors to the radiative losses of the solar chromosphere, and they are enhanced during flares. We have shown previously that the Lyman lines observed by the Extreme Ultraviolet Variability instrument onboard the Solar Dynamics Observatory exhibit Doppler motions equivalent to speeds on the order of 30 km s−1. However, contrary to expectations, both redshifts and blueshifts were present and no dominant flow direction was observed. To understand the formation of the Lyman lines, particularly their Doppler motions, we have used the radiative hydrodynamic code, RADYN, along with the radiative transfer code, RH, to simulate the evolution of the flaring chromosphere and the response of the Lyman lines during solar flares. We find that upflows in the simulated atmospheres lead to blueshifts in the line cores, which exhibit central reversals. We then model the effects of the instrument on the profiles, using the Extreme Ultraviolet Variability Experiment (EVE) instrument's properties. What may be interpreted as downflows (redshifted emission) in the lines, after they have been convolved with the instrumental line profile, may not necessarily correspond to actual downflows. Dynamic features in the atmosphere can introduce complex features in the line profiles that will not be detected by instruments with the spectral resolution of EVE, but which leave more of a signature at the resolution of the Spectral Investigation of the Coronal Environment instrument onboard the Solar Orbiter

Above threshold s-wave resonances illustrated by the 1/2+^+ states in 9^9Be and 9^9B

We solve the persistent problem of the structure of the lowest $1/2^+$ resonance in $^9$Be which is important to bridge the A=8 gap in nucleosynthesis in stars. We show that the state is a genuine three-body resonance even though it decays entirely into neutron-$^8$Be relative s-waves. The necessary barrier is created by "dynamical" evolution of the wave function as the short-distance $\alpha$-$^5$He structure is changed into the large-distance n-$^8$Be structure. This decay mechanism leads to a width about two times smaller than table values. The previous interpretations as a virtual state or a two-body resonance are incorrect. The isobaric analog 1/2$^+$ state in $^9$B is found to have energy and width in the vicinity of 2.0 MeV and 1.5 MeV, respectively. We also predict another 1/2$^+$ resonance in $^9$B with similar energy and width.Comment: To be published in Physics Letters

Capacity of center pivot systems and emitter discharges for citrus irrigation. A case study

Introduction: Given the reduction in water resources, irrigation should be carried out with the highest application efficiency. Irrigation pivots achieve application efficiencies close to localized systems; however, for citrus irrigation, the equations available for its design and management do not contribute to the efficient and rational use of water. Objective: Adapt the expression of the capacity of the machine and propose a new formulation for the discharge of the emitters, to adequately describe the operation of the central pivots for citrus irrigation. Method: Logical research methods were used and within these, the historical method and the deductive logic, to obtain the adequacy and the new equations presented. Results: The expression of the a coefficient was obtained to adapt the expression of the capacity of the machine and two new equations to calculate the necessary discharges of the emitters. They were applied to a case study. Conclusions: It was confirmed that the center pivot machines to irrigate citrus obtain water consumption and application efficiency comparable could with localized irrigation systems.Introducción: Dada la reducción de los recursos hídricos el riego se deberá realizar con la mayor eficiencia de aplicación. Los pivotes de riego alcanzan eficiencias de aplicación cercanas a los sistemas localizados; sin embargo, para el riego de cítricos, las ecuaciones disponibles para su diseño y manejo no contribuyen con el uso eficiente y racional del agua. Objetivo: Adecuar la expresión de la capacidad de la máquina y proponer una nueva formulación para las descargas de los emisores, para describir adecuadamente el funcionamiento de los pivotes centrales para el riego de cítricos. Metodología: Se emplearon métodos lógicos de investigación y dentro de estos, el método histórico y el lógico deductivo, para la obtención de la adecuación y las nuevas ecuaciones presentadas. Resultados: Se obtuvieron la expresión del coeficiente a para adecuar la expresión de la capacidad de la máquina y dos nuevas ecuaciones para calcular las descargas necesarias de los emisores. Se aplicaron a un caso de estudio. Conclusiones: Se confirmó que con las máquinas de pivote central para el riego de los cítricos se pudieran obtener consumo de agua y eficiencia de aplicación, comparables con los sistemas de riego localizado

Spherical Hartree-Fock calculations with linear momentum projection before the variation.Part I: Energies, form factors, charge densities and mathematical sum rules

Spherical Hartree--Fock calculations with projection onto zero total linear momentum before the variation are performed for the nuclei 4He, 12C, 16O, 28Si, 32S and 40Ca using a density--independent effective nucleon--nucleon interaction. The results are compared to those of usual spherical Hartree--Fock calculations subtracting the kinetic energy of the center of mass motion either before or after the variation and to the results obtained analytically with oscillator occupations. Total energies, hole--energies, elastic charge form factors and charge densities and the mathematical Coulomb sum rules are discussed.Comment: 16 pages, 13 postscript figure

Education Burnout and Engagement in Occupational Therapy Undergraduate Students and Its Associated Factors

Burnout syndrome has been characterized as a process of chronic responses to occupational stress in certain employee groups. However, this phenomenon has also been reported in other participant groups including university students. The Maslach Burnout Inventory-Student Survey (MBI-SS), composed of the Exhaustion, Cynicism and Efficacy subscales, was used to evaluate burnout in this sample group while the Utrecht Work Engagement Scale (UWES) was used to gather data related to engagement, a positive psychology construct composed of the three factors, namely vigor, dedication, and absorption. To date, no studies considered these factors in relation to occupational therapy students. This begs the question, is there a relationship between occupational therapy students’ self-reported levels of burnout and engagement? The study objectives are to (1) ascertain the self-reported levels of burnout and engagement in a sample of Australian Occupational undergraduate therapy students, and (2) analyze the sociodemographic, occupational and academic characteristic associated with these levels. The results indicate that a number of demographic and academic study variables are significantly associated with burnout syndrome and education engagement reported by undergraduate occupational therapy students

Stellar lifetime and ultraviolet properties of the old metal-rich Galactic open cluster NGC6791: a pathway to understand the UV upturn of elliptical galaxies

The evolutionary properties of the old metal-rich Galactic open cluster NGC6791 are assessed, based on deep UB photometry and 2Mass JK data. For 4739 stars in the cluster, bolometric luminosity and effective temperature have been derived from theoretical (U-B) and (J-K) color fitting. The derived H-R diagram has been matched with the UVBLUE grid of synthetic stellar spectra to obtain the integrated SED of the system, together with a full set UV (Fanelli) and optical (Lick) narrow-band indices. The cluster appears to be a fairly good proxy of standard elliptical galaxies, although with significantly bluer infrared colors, a shallower 4000A Balmer break, and a lower Mg2 index. The confirmed presence of a dozen hot stars, along their EHB evolution, leads the cluster SED to consistently match the properties of the most active UV-upturn galaxies, with 1.7+/-0.4% of the total bolometric luminosity emitted shortward of 2500A. The cluster Helium abundance results Y=0.30 +/-0.04, while the Post-MS implied stellar lifetime from star number counts fairly agrees with the theoretical expectations from both the Padova and BASTI stellar tracks. A Post-MS fuel consumption of 0.43 +/- 0.01 M_sun is found for NGC6791 stars, in close agreement with the estimated mass of cluster He-rich white dwarfs. Such a tight figure may lead to suspect that a fraction of the cluster stellar population does actually not reach the minimum mass required to effectively ignite He in the stellar core.Comment: A total of 15 pages, with 9 figures and 3 tables. The paper is to appear in the Astrophysical Journal. See http://www.bo.astro.it/~eps/home.html for further data retrieval and future track of the projec

Does intensification result in higher efficiency and sustainability? An emergy analysis of Mediterranean sheep-crop farming systems

The embodiment of resources in agricultural products depends on the way they are made, i.e., the production system. We applied emergy analysis on three contrasting sheep-crop farming systems according to different degrees of specialization, integration and intensification of production in Mediterranean Spain. We studied emergy flows, transformity values and emergy indices at the system level and per product (lamb meat; permanent crops: rainfed olive and almond; arable crops: rainfed barley, irrigated barley, alfalfa and sunflower). We found that the specialized pasture-based sheep system had the lowest intensity and efficiency and the highest sustainability, as opposite to the partially-integrated mixed system, while the fully-integrated mixed system obtained a balanced position. Lamb meat production was 1.9 and 1.3 times more intensive and efficient, respectively, in the partially-integrated mixed system than in the pasture-based sheep system, but 5.1 times less sustainable. All sheep sub-systems had comparatively lower intensity and higher sustainability than crops due to their higher capacity to use local and renewable natural resources. Our findings suggest that further support of agricultural development based on local and renewable natural resources and best practices is necessary to ensure long-term farming sustainability and social welfare

Effect of zinc intake on serum/plasma zinc status in infants: A meta-analysis

A systematic review and meta-analysis of available RCTs was conducted to evaluate the effect of zinc (Zn) intake on serum/plasma Zn status in infants. Out of 5500 studies identified through electronic searches and reference lists, 9 RCTs were selected after applying the exclusion/inclusion criteria. The influence of zinc intake on serum/plasma Zn concentration was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of zinc intake, intervention duration, nutritional status and risk of bias. From each selected study, final measures of serum/plasma Zn were assessed. RESULTS: The pooled β of status was 0.09 (95%CI 0.06 to 0.12). However, a substantial heterogeneity was present in the analyses (I2=95%; p=0.00001). When we performed a meta-regression, the effect of Zn intake on serum/plasma Zn status changed depending on the duration of the intervention, the dose of supplementation and the nutritional situation (p ANCOVA= 0.005; 20 weeks). A positive effect was seen also when doses ranged from 8.1 to 12 mg/day. In all cases, the pooled β showed high evidence of heterogeneity. CONCLUSION: Zinc supplementation increases serum/plasma Zn status in infants, although high evidence of heterogeneity was found. Further standardized research is urgently needed to reach evidence-based conclusions to clarify the role of zinc supplementation upon infant serum/plasma Zn status, particularly in Europe

Joc d’estructures de dades i algorismes

L'activitat consisteix en la implementació d'un jugador per a un joc d'ordinador. L'objectiu és que els estudiants hi apliquin els algorismes i estructures de dades explicats en el curs. Un joc consisteix en un tauler on es mouen agents controlats pels jugadors. Segons les seves accions, cada jugador rep una puntuació, que en finalitzar la partida en determina la classificació. En el joc no hi ha interacció humana: els programes dels estudiants estan escrits abans de cada partida. Per programar un jugador, els estudiants disposen d'informació completa sobre l'estat del tauler i de tots els jugadors. La documentació del joc explica la interfície que el programa de l'estudiant o estudianta ha d'usar per comunicar-se amb el programa principal. Els estudiants disposen d'un servidor web al qual envien els seus jugadors. A més, se'ls proporciona el codi font del joc per poder-ne desenvolupar localment la implementació. L'activitat consta de dues fases. A la primera, els estudiants han de vèncer un jugador de prova, el "beneit", implementat pel professorat i que segueix una estratègia simple. A la segona fase, els estudiants que han superat la primera participen en una eliminatòria per determinar el millor jugador del quadrimestre.Peer Reviewe