212 research outputs found

    Effects of dietary beef tallow on performance, rumen fermentation, carcass traits and meat quality of growing lambs

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    Growing lambs were evaluated for the effect of increasing dietary levels of beef tallow (BT) on performance, rumen fermentation, and carcass and meat characteristics. Twenty-one 5-month-old male Rambouillet lambs were assigned randomly to one of three diets with 0, 20, and 40 g BT/kg dry matter (DM) and similar energy and protein contents. Lambs were adapted to the diets for 15 days, followed by a 45-day evaluation trial. Data were analysed using a mixed model. Growth, feed intake and ruminal fermentation were not affected by the dietary level of BT. Daily metabolizable energy intake (MEI), carcass yield and degree of fatness, increased linearly as the BT level increased. Carcass classification and muscle conformation were not affected by BT. Most meat characteristics (texture, pH, myoglobin, protein content, colour, cathepsins, and chemical composition) five and eight days post-mortem were not affected, except for fat content in meat, which increased linearly as diet BT level increased. Fatty acid (FA) profiles of the meat from lambs fed the three diets were similar. In conclusion, addition of BT at 20 and 40 g/kg DM to diets for growing lambs allowed reduced grain usage and increased forage levels (from 0 to 270 g/kg DM), increasing energy intake, carcass yield and fatness, and intramuscular fat without causing harmful effects on growth, feed intake or ruminal fermentation characteristics. Keywords: dietary fat, fatty acids, meat colour, shee

    Elucidating Individual Magnetic Contributions in Bi-Magnetic Fe3O4/Mn3O4 Core/Shell Nanoparticles by Polarized Powder Neutron Diffraction

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    Heterogeneous bi-magnetic nanostructured systems have had a sustained interest during the last decades owing to their unique magnetic properties and the wide range of derived potential applications. However, elucidating the details of their magnetic properties can be rather complex. Here, a comprehensive study of Fe3O4/Mn3O4 core/shell nanoparticles using polarized neutron powder diffraction, which allows disentangling the magnetic contributions of each of the components, is presented. The results show that while at low fields the Fe3O4 and Mn3O4 magnetic moments averaged over the unit cell are antiferromagnetically coupled, at high fields, they orient parallel to each other. This magnetic reorientation of the Mn3O4 shell moments is associated with a gradual evolution with the applied field of the local magnetic susceptibility from anisotropic to isotropic. Additionally, the magnetic coherence length of the Fe3O4 cores shows some unusual field dependence due to the competition between the antiferromagnetic interface interaction and the Zeeman energies. The results demonstrate the great potential of the quantitative analysis of polarized neutron powder diffraction for the study of complex multiphase magnetic materials

    The relevance of the formation of a pharmaceutical chemist biologist: an element of social renponsability of universities

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    Este estudio de tipo exploratorio, transversal y de campo es solo una fase del proyecto de seguimiento de egresados de la licenciatura en Química Farmacéutico Biológica (QFB) de la Facultad de Estudios Superiores “Zaragoza”. Este proyecto permite retroalimentar el plan curricular, además de establecer el lugar que han ocupado los egresados de esta institución en el mercado laboral, además de detectar las principales áreas de oportunidad en campos profesionales no explorados por los egresados. Así como la determinación de los conocimientos, habilidades, actitudes y valores obtenidos durante su formación y que le han sido indispensables en su desarrollo profesional.This study was exploratory, transversal and field is just one phase of the project following graduates of the FES Zaragoza. This project will provide feedback to the curriculum of the race Pharmaceutical Biological Chemistry (QFB), to establish where they have occupied the graduates of this institution in the labor market, in addition to identifying the main areas of opportunity in professional fields unexplored by the graduates. And the determination of the knowledge, skills, attitudes and values obtained during training and to have been indispensable in their professional development

    Conductance oscillations of a spin-orbit stripe with polarized contacts

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    We investigate the linear conductance of a stripe of spin-orbit interaction in a 2D electron gas; that is, a 2D region of length \ell along the transport direction and infinite in the transverse one in which a spin-orbit interaction of Rashba type is present. Polarization in the contacts is described by means of Zeeman fields. Our model predicts two types of conductance oscillations: Ramsauer oscillations in the minority spin transmission, when both spins can propagate, and Fano oscillations when only one spin propagates. The latter are due to the spin-orbit coupling with quasibound states of the non propagating spin. In the case of polarized contacts in antiparallel configuration Fano-like oscillations of the conductance are still made possible by the spin orbit coupling, even though no spin component is bound by the contacts. To describe these behaviors we propose a simplified model based on an ansatz wave function. In general, we find that the contribution for vanishing transverse momentum dominates and defines the conductance oscillations. Regarding the oscillations with Rashba coupling intensity, our model confirms the spin transistor behavior, but only for high degrees of polarization. Including a position dependent effective mass yields additional oscillations due to the mass jumps at the interfaces.Comment: 8.5 pages, 9 figure

    Elucidating Individual Magnetic Contributions in Bi-Magnetic Fe3O4/Mn3O4 Core/Shell Nanoparticles by Polarized Powder Neutron Diffraction

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    Heterogeneous bi-magnetic nanostructured systems have had a sustained interest during the last decades owing to their unique magnetic properties and the wide range of derived potential applications. However, elucidating the details of their magnetic properties can be rather complex. Here, a comprehensive study of FeO/MnO core/shell nanoparticles using polarized neutron powder diffraction, which allows disentangling the magnetic contributions of each of the components, is presented. The results show that while at low fields the FeO and MnO magnetic moments averaged over the unit cell are antiferromagnetically coupled, at high fields, they orient parallel to each other. This magnetic reorientation of the MnO shell moments is associated with a gradual evolution with the applied field of the local magnetic susceptibility from anisotropic to isotropic. Additionally, the magnetic coherence length of the FeO cores shows some unusual field dependence due to the competition between the antiferromagnetic interface interaction and the Zeeman energies. The results demonstrate the great potential of the quantitative analysis of polarized neutron powder diffraction for the study of complex multiphase magnetic materials

    Unusual magnetic relaxation behavior in La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3

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    We have carried out a systematic magnetic relaxation study, measured after applying and switching off a 5 T magnetic field to polycrystalline samples of La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3. The long time logarithmic relaxation rate (LTLRR), decreased from 10 K to 150 K and increased from 150 K to 195 K in La0.5Ca0.5MnO3. This change in behavior was found to be related to the complete suppression of the antiferromagnetic phase above 150 K and in the presence of a 5 T magnetic field. At 195 K, the magnetization first decreased, and after a few minutes increased slowly as a function of time. Moreover, between 200 K and 245 K, the magnetization increased throughout the measured time span. The change in the slope of the curves, from negative to positive at about 200 K was found to be related to the suppression of antiferromagnetic fluctuations in small magnetic fields. A similar temperature dependence of the LTLRR was found for the Nd0.5Sr0.5MnO3 sample. However, the temperature where the LTLRR reached the minimum in Nd0.5Sr0.5MnO3 was lower than that of La0.5Ca0.5MnO3. This result agrees with the stronger ferromagnetic interactions that exist in Nd0.5Sr0.5MnO3 in comparison to La0.5Ca0.5MnO3. The above measurements suggested that the general temperature dependence of the LTLRR and the underlying physics were mainly independent of the particular charge ordering system considered. All relaxation curves could be fitted using a logarithmic law at long times. This slow relaxation was attributed to the coexistence of ferromagnetic and antiferromagnetic interactions between Mn ions, which produced a distribution of energy barriers.Comment: Accepted to PRB as a regular article, 10 figures, Scheduled Issue: 01 June 200

    Molecular and Cellular Mechanisms of Delayed Fracture Healing in Mmp10 (Stromelysin 2) Knockout Mice

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    The remodeling of the extracellular matrix is a central function in endochondral ossification and bone homeostasis. During secondary fracture healing, vascular invasion and bone growth requires the removal of the cartilage intermediate and the coordinate action of the collagenase matrix metalloproteinase (MMP)-13, produced by hypertrophic chondrocytes, and the gelatinase MMP-9, produced by cells of hematopoietic lineage. Interfering with these MMP activities results in impaired fracture healing characterized by cartilage accumulation and delayed vascularization. MMP-10, Stromelysin 2, a matrix metalloproteinase with high homology to MMP-3 (Stromelysin 1), presents a wide range of putative substrates identified in vitro, but its targets and functions in vivo and especially during fracture healing and bone homeostasis are not well defined. Here, we investigated the role of MMP-10 through bone regeneration in C57BL/6 mice. During secondary fracture healing, MMP-10 is expressed by hematopoietic cells and its maximum expression peak is associated with cartilage resorption at 14 days post fracture (dpf). In accordance with this expression pattern, when Mmp10 is globally silenced, we observed an impaired fracture-healing phenotype at 14 dpf, characterized by delayed cartilage resorption and TRAP-positive cell accumulation. This phenotype can be rescued by a non-competitive transplant of wild-type bone marrow, indicating that MMP-10 functions are required only in cells of hematopoietic linage. In addition, we found that this phenotype is a consequence of reduced gelatinase activity and the lack of proMMP-9 processing in macrophages. Our data provide evidence of the in vivo function of MMP-10 during endochondral ossification and defines the macrophages as the lead cell population in cartilage removal and vascular invasio

    Controlled clinical trial comparing the effectiveness of a mindfulness and self-compassion 4-session programme versus an 8-session programme to reduce work stress and burnout in family and community medicine physicians and nurses: MINDUUDD study protocol

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    Background: Health personnel are susceptible to high levels of work stress and burnout due to the psychological and emotional demands of their work, as well as to other aspects related to the organisation of that work. This paper describes the rationale and design of the MINDUUDD study, the aim of which is to evaluate the effectiveness of a mindfulness and self-compassion 4-session programme versus the standard 8-session programme to reduce work stress and burnout in Family and Community Medicine and Nursing tutors and residents. Methods: The MINDUDD study is a multicentre cluster randomised controlled trial with three parallel arms. Six Teaching Units will be randomised to one of the three study groups: 1) Experimental Group-8 (EG8); 2) Experimental Group-4 (EG4) Control group (CG). At least 132 subjects will participate (66 tutors/66 residents), 44 in the EG8, 44 in the EG4, and 44 in the CG. Interventions will be based on the Mindfulness-Based Stress Reduction (MBSR) program, including some self-compassion practices of the Mindful Self-Compassion (MSC) programme. The EG8 intervention will be implemented during 8 weekly face-to-face sessions of 2.5 h each, while the EG4 intervention will consist of 4 sessions of 2.5 h each. The participants will have to practice at home for 30 min/day in the EG8 and 15 min/day in the EG4. The Five Facet Mindfulness Questionnaire (FFMQ), Self-Compassion Scale (SCS), Perceived Stress Questionnaire (PSQ), Maslach Burnout Inventory (MBI), Jefferson Scale of Physician Empathy (JSPE), and Goldberg Anxiety-Depression Scale (GADS) will be administered. Measurements will be taken at baseline, at the end of the programs, and at three months after completion. The effect of the interventions will be evaluated by bivariate and multivariate analyses (Multiple Linear Regression). Discussion: If the abbreviated mindfulness programme is at least as effective as the standard program, its incorporation into the curriculum and training plans will be easier and more appropriate. It will also be more easily applied and accepted by primary care professionals because of the reduced resources and means required for its implementation, and it may also extend beyond care settings to academic and teaching environments as well

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

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    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg(E/eV)=18.519.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe
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