3,740 research outputs found

    The impact of college students’ motivational orientations and the social dimension of emotional intelligence in their willingness to study abroad

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    This study investigated the effect of motivational orientations and the social aspects of emotional intelligence (EI) on L2 Spanish learners’ willingness to participate in a study abroad program. The only significant result was the correlation between an integrative motivational orientation and the Altruism Scale score (N = 68, r = .290, p \u3c .05), indicating that those learners with a higher desire to learn the L2 in order to interact with members of the target community also showed more responsiveness to others as measured by empathy, nurturance, helpfulness, and social responsibility. No additional interactions were found between the motivational orientations and the social aspects of EI. Neither the motivational orientations (integrative/instrumental) nor the social subscales of EI used correlated with the L2 learners’ participation in a short-term (three weeks to Costa Rica, N = 30) or a long-term study abroad program (a full semester to Spain, N = 13). This finding is indicative that those variables do not seem to have an influential effect or predictability on whether participants would ultimately continue their study of L2 Spanish in a foreign country or at home in the near future

    Flow injection determination of readily assimilable nitrogen compounds during vinification

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    A flow injection method for the determination of readily assimilable nitrogen (r.a.n.), i.e. ammonium and aminated nitrogen, is reported. The difference in pH of the sample in the presence and absence of formaldehyde, which blocks the amino function, provides the value of r.a.n. by monitoring the changes in absorbance of bromothymol blue at 616 nm. The detection and quantification limits are 10 and 11.6 mg l-1, respectively; the reproducibility and repeatability are 3.94 mg l-1 and 1.35 mg l-1, respectively; and the sample throughput is 20 samples h-1. The method has been applied to the analysis of 120 samples of must and wine subjected to biological aging. The proposed method also provides good correlation with the reference method used in routine analysis, and it is faster and gives sufficient precision for wineries requirements

    VO2max test is not altered by a submaximum exercise

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    INTRODUCTION: The Maximum Oxygen Consumption (VO2max) and Ventilatory anaerobic threshold (VT), is measured using progressive exercise protocol until exhaustion, these results can be affected by a previous submaximum exercise. PURPOSE: The purpose of this study was evaluate the reproducibility of maximum effort test after a submaximum exercise. METHODS: 19 subjects (mean ± SD; age, 21.8±2.5 years; body mass, 71.0±10.6 and height, 175.2±8.1) participated in this study. During two days of assessment separately for at least 24h recovery subjects performed the following tests: Day 1 a maximum effort test and a submaximum exercise at 80% of VO2max. Day 2 the order of the tests performed on day 1 was reversed. RESULTS: No significant differences were found in the VO2max or ventilatory thresholds determined in both tests of maximum effort. (VO2max 54.2 ± 6.8vs 55.1 ± 6.4 (ml·kg-1·min-1), ICC; 0.91, CV; 3.9 ± 2.1); (VO2 RCT 45.6 ± 6.4vs 45.9 ± 5.7 (ml·kg-1·min-1) ICC; 0.96, CV; 3.0 ± 2.1)( VO2 VT 35.6 ± 4.7vs 35.6 ± 4.7 (ml·kg-1·min-1) ICC; 0.87, CV; 4.9 ± 3.9). CONCLUSION: The results of the present study showed a high reproducibility of the data obtained when maximum effort test is assessed (i.e., VO2max and ventilatory threshold), regardless the submaximum exercise

    Potential of bacteriophage K as an antimicrobial strategy against biofilms of Staphylococcus aureus in the food industry

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    1 poster presented at the 24th International ICFMH Conference, Food Micro 2014, 1-4 Septembre, Nantes, FranceThe potential of phage K in the removal and prevention of Staphylococcus aureus biofilms on stainless steel surfaces was examined. The host range of the phage was tested on 18 strains from the food industry. Two out of six sensitive strains were selected for study of biofilms. Immature 6-h-old biofilms were challenged wfth a wide range of multipticlties of infection {MOl, 0.01-500) for 18 h at 25ºc. A noticeable effect on cell number was appreciated at MOIs≥10, but no effect was detected at lower MOis. Subsequently, 24 h-old biofilms (with a higher cell density and a more dense extracellular matrix) were challenged too at MOIs between 0.01-3.0 for 24 hat 25ºc. Again, a significant effect was only found at MOls > 1. The effectiveness in the prevention of biofilm formation was examined by Infecting planktonlc cultures of S. aureus with sub-lethal and lethal doses of phage K (MOIs 1-10-7-10.0). A notable effect on cell number and biofilm biomass was observed from MOIs >1·10-5. The potential of phage K as a tool for biohygienization in the food Industry acting specifically against biofilms of S. aureus was thus shown. However, neither biofilm cells were completely removed nor biofilm formation was totally prevented, and a sub-population of live cells was left In both cases As a result, the effectiveness of two co-adjuvant-based strategies was subsequently assessed. Combining DNase (0,1-10 mg/ml) with phage K (MOl of 0.3-3.0) did not show an additional effect on the removal of 24 h-old-biofilms at 25°C. A 30 min pre-treatment at 37ºc aimed to enhance DNase activity also had not effect. DNase did not show any effects by itself either. In contrast, combining cis-2-decenoic acid {1 - 100 nM) with phage K (MOl of 0.03-0.3) seemed to show some effects on biofilmsN

    Carboxyl-modified single-wall carbon nanotubes improve bone tissue formation in vitro and repair in an in vivo rat model.

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    The clinical management of bone defects caused by trauma or nonunion fractures remains a challenge in orthopedic practice due to the poor integration and biocompatibility properties of the scaffold or implant material. In the current work, the osteogenic properties of carboxyl-modified single-walled carbon nanotubes (COOH-SWCNTs) were investigated in vivo and in vitro. When human preosteoblasts and murine embryonic stem cells were cultured on coverslips sprayed with COOH-SWCNTs, accelerated osteogenic differentiation was manifested by increased expression of classical bone marker genes and an increase in the secretion of osteocalcin, in addition to prior mineralization of the extracellular matrix. These results predicated COOH-SWCNTs' use to further promote osteogenic differentiation in vivo. In contrast, both cell lines had difficulties adhering to multi-walled carbon nanotube-based scaffolds, as shown by scanning electron microscopy. While a suspension of SWCNTs caused cytotoxicity in both cell lines at levels >20 μg/mL, these levels were never achieved by release from sprayed SWCNTs, warranting the approach taken. In vivo, human allografts formed by the combination of demineralized bone matrix or cartilage particles with SWCNTs were implanted into nude rats, and ectopic bone formation was analyzed. Histological analysis of both types of implants showed high permeability and pore connectivity of the carbon nanotube-soaked implants. Numerous vascularization channels appeared in the formed tissue, additional progenitor cells were recruited, and areas of de novo ossification were found 4 weeks post-implantation. Induction of the expression of bone-related genes and the presence of secreted osteopontin protein were also confirmed by quantitative polymerase chain reaction analysis and immunofluorescence, respectively. In summary, these results are in line with prior contributions that highlight the suitability of SWCNTs as scaffolds with high bone-inducing capabilities both in vitro and in vivo, confirming them as alternatives to current bone-repair therapies

    Sistemas caóticos y su aplicación a la encriptación de señales

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    La sincronización y control de señales caóticas es una activa área de investigación por sus posibles aplicaciones en telecomunicaciones y transmisión de señales [1, 2, 3, 4]. En el presente trabajo se estudia un sistema de comunicación basado en la sincronización de dos sistemas no lineales caóticos, cada uno modelado a partir de las ecuaciones de movimiento de un péndulo forzado amortiguado y que se encuentran en el mismo punto de operación del espacio de parámetros. Synchronization and control of chaotic signals is an active research area because of its applications in telecommunications and secure signal transmission [1,2,3,4]. In this work a communication system based in the synchronization of two chaotic nonlinear systems, each one being modeled by the motion equations of a driven damped pendulum and operated in the same parameter space region is shown. Two communication channels were used: the first one for the synchronizing signal and the second one for the sent message. By using two channels the initial conditions sensibility problem is solved. In the receiver system a feedback loop as a proportional controller is used in order to drive quickly the error between the decoder and encoder states to zero. The last two facts make the system to be robust to external pertubative signals such as noise in the communication channels

    Recruitment patterns of decapod crustacean megalopae in a shallow inlet (SW Spain) related to life history strategies

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    Decapod crustacean megalopae were sampled weekly (spring/neap tides) during late-spring/summer of 1998 by using two planktonic nets located close to the surface and the bottom, at a fixed station in the mouth of the Rı́o San Pedro inlet (SW Spain). Sampling was carried out during 25 h cycles to ascertain the flux of megalopae in relation to the main environmental (diel, tidal, tidal amplitude) cycles. The hypothesis that megalopae of some species may be using tidal-stream transport as a mechanism of re-invading the inlet was tested and the relationship between megalopal behaviour and life history strategy was analysed. In general, the flux of megalopae was higher during spring tides, but such differences were only statistically significant for Pisidia longicornis and Liocarcinus sp.2 due to the considerable interdate variation. With the exception of Macropodia sp., megalopae were more abundant close to the bottom. The diel/tidal flux of most abundant species suggested two different patterns of behaviour: megalopae of Liocarcinus spp., Panopeus africanus, Uca tangeri and Brachynotus sexdentatus seemed to be re-invading the inlet (specially at nocturnal floods), while megalopae of Ilia nucleus, Nepinnotheres pinnotheres and Macropodia sp. may have been just looking for a suitable place for settlement. The first group corresponded to the species whose zoeal development occurs in open sea, and the second one to species that complete their life cycle within the studied system, suggesting a relationship between the duration of the larval phase and the life cycle strategy of the species

    Quinolones modulate ghrelin receptor signaling: potential for a novel small molecule scaffold in the treatment of cachexia

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    Cachexia is a metabolic wasting disorder characterized by progressive weight loss, muscle atrophy, fatigue, weakness, and appetite loss. Cachexia is associated with almost all major chronic illnesses including cancer, heart failure, obstructive pulmonary disease, and kidney disease and significantly impedes treatment outcome and therapy tolerance, reducing physical function and increasing mortality. Current cachexia treatments are limited and new pharmacological strategies are needed. Agonists for the growth hormone secretagogue (GHS-R1a), or ghrelin receptor, prospectively regulate the central regulation of appetite and growth hormone secretion, and therefore have tremendous potential as cachexia therapeutics. Non-peptide GHS-R1a agonists are of particular interest, especially given the high gastrointestinal degradation of peptide-based structures, including that of the endogenous ligand, ghrelin, which has a half-life of only 30 min. However, few compounds have been reported in the literature as non-peptide GHS-R1a agonists. In this paper, we investigate the in vitro potential of quinolone compounds to modulate the GHS-R1a in both transfected human cells and mouse hypothalamic cells. These chemically synthesized compounds demonstrate a promising potential as GHS-R1a agonists, shown by an increased intracellular calcium influx. Further studies are now warranted to substantiate and exploit the potential of these novel quinolone-based compounds as orexigenic therapeutics in conditions of cachexia and other metabolic and eating disorders.Irish Research Council for Science and Technology (IRCSET)Science Foundation Ireland (SFI/12/IP/1315)Science Foundation Ireland (SFI/12/RC/2275)Science Foundation Ireland (SFI/12/RC/2273)Universidad de Sevill

    Phononic heat conductance of gold atomic contacts: Coherent versus incoherent transport

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    We present here a theoretical method to determine the phononic contribution to the thermal conductance of nanoscale systems in the phase-coherent regime. Our approach makes use of classical molecular dynamics (MD) simulations to calculate the temperature-dependent dynamical matrix, and the phononic heat conductance is subsequently computed within the Landauer-Büttiker formalism with the help of nonequilibrium Green's function techniques. Tailored to nanostructures, crucial steps of force constant and heat transport calculations are performed directly in real space. As compared to conventional density functional theory (DFT) approaches, the advantage of our method is twofold. First, interatomic interactions can be described with the method of choice. Semiempirical potentials may lead to large computational speedups, enabling the study of much larger systems. Second, the method naturally takes into account the temperature dependence of atomic force constants, an aspect that is ignored in typical static DFT-based calculations. We illustrate our method by analyzing the temperature dependence of the phononic thermal conductance of gold (Au) chains with lengths ranging from 1 to 12 atoms. Moreover, in order to evaluate the importance of anharmonic effects in these atomic-scale wires, we compare the phase-coherent approach with nonequilibrium MD (NEMD) simulations. We find that the predictions of the phase-coherent method and the classical NEMD approach largely agree above the Debye temperature for all studied chain lengths, which shows that heat transport is coherent and that our phase-coherent approach is well suited for such nanostructure
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