1,787 research outputs found

    Dynamic screening of a localized hole during photoemission from a metal cluster

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    Recent advances in attosecond spectroscopy techniques have fueled the interest in the theoretical description of electronic processes taking place in the subfemtosecond time scale. Here we study the coupled dynamic screening of a localized hole and a photoelectron emitted from a metal cluster using a semi-classical model. Electron density dynamics in the cluster is calculated with Time-Dependent Density Functional Theory and the motion of the photoemitted electron is described classically. We show that the dynamic screening of the hole by the cluster electrons affects the motion of the photoemitted electron. At the very beginning of its trajectory, the photoemitted electron interacts with the cluster electrons that pile up to screen the hole. Within our model, this gives rise to a significant reduction of the energy lost by the photoelectron. Thus, this is a velocity dependent effect that should be accounted for when calculating the average losses suffered by photoemitted electrons in metals.Comment: 15 pages, 5 figure

    Estudio de la inteligencia emocional en escolares de educación primaria: Alcance en el área de educación física

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    Emotional Intelligence (EI) can be considered an ability to achieve more meaningful learning, if carried out during the teaching-learning processes. This is so, since, for each situation that appears in the classroom during the teaching processes, it involves one or several emotions unleashed by those situations, and it is here that the teacher can positively and significantly reinforce the dimensions of that emotion or emotions arisen. Having emotional balance means having a good physical and mental well-being, since the healthier our emotions are, the better we will feel in different daily situations. On the other hand, performing a Physical Activity (AF) or any sport is beneficial for physical and mental well-being, since physical activity involves a series of positive emotions in the individuals who practice it. Like positive emotions, FA produces negative emotions, so we have chosen to reinforce and counteract these emotions during the practice of Physical Education (PE) in Primary Education, since the sooner these emotions are redirected, the better emotional balance and better learning is going to be achieved, and as better than to be done from the area of ​​EF, and promoted by a teacher.La Inteligencia Emocional (IE) se puede considerar una habilidad para conseguir un aprendizaje más significativo, si se lleva a cabo durante los procesos de enseñanza-aprendizaje. Esto es así, ya que, por cada situación que aparezca en el aula durante los procesos de enseñanza, conlleva una o varias emociones desatadas por esas situaciones, y es aquí donde el docente puede reforzar de forma positiva y significativa las dimensiones de esa emoción u emociones surgidas. Tener equilibrio emocional significa tener un buen bienestar físico y mental, puesto que cuanto más saludables sean nuestras emociones, mejor nos vamos a sentir en diferentes situaciones diarias. Por otro lado, realizar una Actividad Física (AF) o cualquier deporte, es beneficioso para el bienestar físico y mental, ya que, realizar actividad física conlleva una serie de emociones positivas en los individuos que la practiquen. Al igual, que emociones positivas, la AF produce emociones negativas, por lo que hemos optado por reforzar y contrarrestar estas emociones durante la práctica de Educación Física (EF) en Educación Primaria, puesto que cuánto antes se redirijan estas emociones, mejor equilibrio emocional y mejor aprendizaje se va a conseguir, y como mejor que realizarlo a partir del área de EF, y promovido por un docente

    Cosmology from large-scale structure. Constraining LambdaCDM with BOSS

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    We reanalyse the anisotropic galaxy clustering measurement from the Baryon Oscillation Spectroscopic Survey (BOSS), demonstrating that using the full shape information provides cosmological constraints that are comparable to other low-redshift probes. We find Ωm = 0.317+0.015−0.019, σ8 = 0.710±0.049, and h = 0.704 ± 0.024 for flat ΛCDM cosmologies using uninformative priors on Ωch2, 100θMC, ln1010As, and ns, and a prior on Ωbh2 that is much wider than current constraints. We quantify the agreement between the Planck 2018 constraints from the cosmic microwave background and BOSS, finding the two data sets to be consistent within a flat ΛCDM cosmology using the Bayes factor as well as the prior-insensitive suspiciousness statistic. Combining two low-redshift probes, we jointly analyse the clustering of BOSS galaxies with weak lensing measurements from the Kilo-Degree Survey (KV450). The combination of BOSS and KV450 improves the measurement by up to 45%, constraining σ8 = 0.702 ± 0.029 and S8 = σ8 Ωm/0.3 = 0.728 ± 0.026. Over the full 5D parameter space, the odds in favour of a single cosmology describing galaxy clustering, lensing, and the cosmic microwave background are 7 ± 2. The suspiciousness statistic signals a 2.1 ± 0.3σ tension between the combined low-redshift probes and measurements from the cosmic microwave background

    Construct and face validity of SINERGIA laparoscopic virtual reality simulator

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    Purpose Laparoscopic techniques have nowadays become a gold standard in many surgical procedures, but they imply a more difficult learning skills process. Simulators have a fundamental role in the formative stage of new surgeons. This paper presents the construct and face validity of SINERGIA laparoscopic virtual reality simulator in order to decide whether it can be considered as an assessment tool. Methods Twenty people participated in this study, 14 were novices and 6 were experts. Five tasks of SINERGIA were included in the study: coordination, navigation, navigation and touch, precise grasping and coordinate traction. For each one of these tasks, a certain number of metrics are automatically recorded. All subjects accomplished each task only once and filled in two questionnaires. A statistical analysis was made and results from both groups were compared with the Mann–Whitney U-test, considering significant differences when P ≤ 0.05. Internal consistency of the system has been analyzed with the Cronbach’s alpha test. Results Novices and experts positively rated SINERGIA characteristics. At least one of the evaluated metrics of each exercise presented significant differences between both groups. Nevertheless, all metrics under study gave a better punctuation to the executions accomplished by experts (lower time, higher efficiency, fewer errors. . .) than to those made by novices. Conclusion SINERGIA laparoscopic virtual reality simulator is able to discriminate subjects according to their level of experience in laparoscopic surgery; therefore, it can be used within a training program as an assessment too

    High burden and frailty: association with poor cognitive performance in older caregivers living in rural areas

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    Introduction: Older caregivers living in rural areas may be exposed to three vulnerable conditions, i.e., those related to care, their own aging, and their residence context. Objective: To analyze the association of burden and frailty with cognition performance in older caregivers in rural communities. Method: In this cross-sectional survey, 85 older caregivers who cared for dependent elders were included in this study. Global cognition (Addenbrooke's Cognitive Examination – Revised; Mini Mental State Examination), burden (Zarit Burden Interview) and frailty (Fried's frailty phenotype) were assessed. All ethical principles were observed. Results: Older caregivers were mostly women (76.7%); mean age was 69 years. Cognitive impairment was present in 15.3%, severe burden in 8.2%, frailty in 9.4%, and pre-frailty in 52.9% of the older caregivers. More severely burdened or frail caregivers had worse cognitive performance than those who were not, respectively (ANOVA test). Caregivers presenting a high burden level and some frailty degree (pre-frail or frail) simultaneously were more likely to have a reduced global cognition performance. Conclusion: A significant number of older caregivers had low cognitive performance. Actions and resources to decrease burden and physical frailty may provide better cognition and well-being, leading to an improved quality of life and quality of the care provided by the caregivers

    Magnetic Coupling in the Quiet Solar Atmosphere

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    Three kinds of magnetic couplings in the quiet solar atmosphere are highlighted and discussed, all fundamentally connected to the Lorentz force. First the coupling of the convecting and overshooting fluid in the surface layers of the Sun with the magnetic field. Here, the plasma motion provides the dominant force, which shapes the magnetic field and drives the surface dynamo. Progress in the understanding of the horizontal magnetic field is summarized and discussed. Second, the coupling between acoustic waves and the magnetic field, in particular the phenomenon of wave conversion and wave refraction. It is described how measurements of wave travel times in the atmosphere can provide information about the topography of the wave conversion zone, i.e., the surface of equal Alfv\'en and sound speed. In quiet regions, this surface separates a highly dynamic magnetic field with fast moving magnetosonic waves and shocks around and above it from the more slowly evolving field of high-beta plasma below it. Third, the magnetic field also couples to the radiation field, which leads to radiative flux channeling and increased anisotropy in the radiation field. It is shown how faculae can be understood in terms of this effect. The article starts with an introduction to the magnetic field of the quiet Sun in the light of new results from the Hinode space observatory and with a brief survey of measurements of the turbulent magnetic field with the help of the Hanle effect.Comment: To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

    Safety outcomes during pediatric GH therapy: final results from the prospective GeNeSIS observational program

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    CONTEXT: Safety concerns regarding premature mortality, diabetes, neoplasia and cerebrovascular disease in association with growth hormone (GH) therapy have been raised. OBJECTIVE: To assess incidence of key safety outcomes. DESIGN: Prospective, multinational, observational study (1999-2015). SETTING: 22,311 GH-treated children from 827 investigative sites in 30 countries. PATIENTS: Children with growth disorders. INTERVENTIONS: GH treatment. MAIN OUTCOME MEASURES: Standardized mortality (SMR) and incidence (SIR) ratios with 95% confidence intervals (CI) for mortality, diabetes, and primary cancer, using general population registries. RESULTS: Predominant short stature diagnoses were GH deficiency (63%), idiopathic short stature (13%), and Turner syndrome (8%), with mean±SD follow-up of 4.2±3.2 years (∼92,000 person-years [PY]). Forty-two deaths occurred in patients with follow-up, with SMR (95% CI) of 0.61 (0.44-0.82); the SMR was elevated for patients with cancer-related organic GH deficiency (5.87 [3.21-9.85]). Based on 18 cases, Type 2 diabetes (T2DM) risk was elevated (SIR 3.77 [2.24-5.96]), but 72% had risk factors. In patients without cancer history, 14 primary cancers were observed (SIR 0.71 [0.39-1.20]). Second neoplasms occurred in 31/622 (5.0%) cancer survivors (10.7 [7.5-15.2] cases/1000 PY), and intracranial tumor recurrences in 67/823 (8.1%) tumor survivors (16.9 [13.3-21.5] cases/1000 PY). All 3 hemorrhagic stroke cases had risk factors. CONCLUSIONS: GeNeSIS data support the favourable safety profile of pediatric GH treatment. Overall risk for death or primary cancer was not elevated in GH-treated children, and no hemorrhagic strokes occurred in patients without risk factors. T2DM incidence was elevated compared to the general population, but most cases had diabetes risk factors

    Hydrogen sulfide donors alleviate itch secondary to the activation of type-2 protease activated receptors (PAR-2) in mice.

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    Published onlineJOURNAL ARTICLEHydrogen sulfide (H2S) has been highlighted as an endogenous signaling molecule and we have previously found that it can inhibit histamine-mediated itching. Pruritus is the most common symptom of cutaneous diseases and anti-histamines are the usual treatment; however, anti-histamine-resistant pruritus is common in some clinical settings. In this way, the involvement of mediators other than histamine in the context of pruritus requires new therapeutic targets. Considering that the activation of proteinase-activated receptor 2 (PAR-2) is involved in pruritus both in rodents and humans, in this study we investigated the effect of H2S donors on the acute scratching behavior mediated by PAR-2 activation in mice, as well as some of the possible pharmacological mechanisms involved. The intradermal injection of the PAR-2 peptide agonist SLIGRL-NH2 (8-80nmol) caused a dose-dependent scratching that was unaffected by intraperitoneal pre-treatment with the histamine H1 antagonist pyrilamine (30mg/kg). Co-injection of SLIGRL-NH2 (40nmol) with either the slow-release H2S donor GYY4137 (1 and 3nmol) or the spontaneous donor NaHS (1 and 0.3nmol) significantly reduced pruritus. Co-treatment with the KATP channel blocker glibenclamide (200nmol) or the nitric oxide (NO) donor sodium nitroprusside (10nmol) abolished the antipruritic effects of NaHS; however, the specific soluble guanylyl cyclase inhibitor ODQ (30μg) had no significant effects. The transient receptor potential ankyrin type 1 (TRPA1) antagonist HC-030031 (20μg) significantly reduced SLIGRL-NH2-induced pruritus; however pruritus induced by the TRPA1 agonist AITC (1000nmol) was unaffected by NaHS. Based on these data, we conclude that pruritus secondary to PAR-2 activation can be reduced by H2S, which acts through KATP channel opening and involves NO in a cyclic guanosine monophosphate (cGMP)-independent manner. Furthermore, TRPA1 receptors mediate the pruritus induced by activation of PAR-2, but H2S does not interfere with this pathway. These results provide additional support for the development of new therapeutical alternatives, mainly intended for treatment of pruritus in patients unresponsive to anti-histamines.MNM and SKPC are recipients of fellowships from the National Council for Scientific and Technological Development (CNPq) and grants from the Sao Paulo Research Foundation (FAPESP). RT, MW and MEW would like to thank the Brian Ridge Scholarship for its support (RT)
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