553 research outputs found

    Analysis of torque measurements on films with oblique anisotropy

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    A measurement method is discussed to determine the magnetic anisotropy energy in a sample without assuming an a priori model for the origins of the anisotropy. The measurement procedure involves torque measurements in five different planes. Since it is especially useful for films with an oblique anisotropy axis, the method is illustrated on an obliquely evaporated Co80Ni20 fil

    Static wormholes on the brane inspired by Kaluza-Klein gravity

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    We use static solutions of 5-dimensional Kaluza-Klein gravity to generate several classes of static, spherically symmetric spacetimes which are analytic solutions to the equation (4)R=0^{(4)}R = 0, where (4)R^{(4)}R is the four-dimensional Ricci scalar. In the Randall & Sundrum scenario they can be interpreted as vacuum solutions on the brane. The solutions contain the Schwarzschild black hole, and generate new families of traversable Lorenzian wormholes as well as nakedly singular spacetimes. They generalize a number of previously known solutions in the literature, e.g., the temporal and spatial Schwarzschild solutions of braneworld theory as well as the class of self-dual Lorenzian wormholes. A major departure of our solutions from Lorenzian wormholes {\it a la} Morris and Thorne is that, for certain values of the parameters of the solutions, they contain three spherical surfaces (instead of one) which are extremal and have finite area. Two of them have the same size, meet the "flare-out" requirements, and show the typical violation of the energy conditions that characterizes a wormhole throat. The other extremal sphere is "flaring-in" in the sense that its sectional area is a local maximum and the weak, null and dominant energy conditions are satisfied in its neighborhood. After bouncing back at this second surface a traveler crosses into another space which is the double of the one she/he started in. Another interesting feature is that the size of the throat can be less than the Schwarzschild radius 2M2 M, which no longer defines the horizon, i.e., to a distant observer a particle or light falling down crosses the Schwarzschild radius in a finite time

    Nonlinear parametric instability in double-well lattices

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    A possibility of a nonlinear resonant instability of uniform oscillations in dynamical lattices with harmonic intersite coupling and onsite nonlinearity is predicted. Numerical simulations of a lattice with a double-well onsite anharmonic potential confirm the existence of the nonlinear instability with an anomalous value of the corresponding power index, 1.57, which is intermediate between the values 1 and 2 characterizing the linear and nonlinear (quadratic) instabilities. The anomalous power index may be a result of competition between the resonant quadratic instability and nonresonant linear instabilities. The observed instability triggers transition of the lattice into a chaotic dynamical state.Comment: A latex text file and three pdf files with figures. Physical Review E, in pres

    Effects of resistance training program on muscle mass and muscle strength and the relationship with cognition in Older Women

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    The aim of this study was to study the effects of a resistance training programme on Maximal Dynamic Strength (MDS) and muscle morphology of the upper limbs (UL) and lower limbs (LL), as well as to analyse their association with cognition, in a population of older women. The study had a duration of 24 months and a total of 93 Chilean older women participated. The participants were divided into two groups: The Physical Activity Group (PAG, n = 45, age (X ± SD) 77.93 ± 3.54 years), and the Sedentary Group (SG, n = 48, age (X ± SD) 77.71 ± 3.41 years). The PAG carried out a muscle strength training routine twice per week. The following variables were evaluated: Muscle function through maximal dynamic strength (1RM), muscle morphology through arm and calf circumference (AC and CC, respectively), and cognition (Mini Mental State Examination: MMSE). The results show that the SG recorded significant decreases (percent changes; p < 0.05) in the analysed variables: MMSE (-3.5%), MDS in UL (-3.3%), MDS in LL (-4.1%), AC (-4.5%), CC (-4.1%), and BMI (-3.1%). However, the PAG improved significantly in all the analysed variables except in BMI: MMSE (3.9%), MDS in UL (3.6%), MDS in LL (3.5%), AC (1.8%), and CC (2.5%). Moreover, there was a significant association (p < 0.05) between the changes in the muscle strength variables and the changes in cognition level. Therefore, it can be concluded that a two-year muscle strength training programme (load intensity between 30-55% 1RM) in older women improves Maximal Dynamic Strength in UL and LL, as well as muscle mass in arms and calves. Furthermore, it can be asserted that the changes in muscle strength levels could predict the changes in the levels of cognition in older women. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    A field outbreak in Ile-de-France sheep of a cardiotoxicosis caused by the plant Pachystigma pygmaeum (Schltr) Robyns (Rubiaceae)

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    A field outbreak of Pachystigma pygmaeum intoxication in sheep is described. Noteworthy clinical signs were: respiratory distress, apathy and subcutaneous oedema of mainly the head. Gross changes included cardiomegaly, centrilobular hepatic necrosis and effusion of body cavities. Microscopically myocardial fibrosis, affecting predominantly the endocardium of the apex, left free ventricular wall and interventricular septum, was most striking in the majority of animals, whilst myofibre atrophy was present in 1 sheep.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

    Characterizing top gated bilayer graphene interaction with its environment by Raman spectroscopy

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    In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We theoretically analyze our data in terms of the bilayer graphene phonon self-energy which includes non-homogeneous charge carrier doping between the graphene layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the interaction of bilayer graphene with its surrounding environment

    A randomised controlled trial comparing oxytocin and oxytocin + ergometrine for prevention of postpartum haemorrhage at caesarean section

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    BACKGROUND. Globally 166 000 women die annually as a result of obstetric haemorrhage. More than 50% of these deaths occur in sub- Saharan Africa. Uterine atony is the commonest cause of severe postpartum haemorrhage (PPH). Bleeding at or after caesarean section (CS) is responsible for >30% of maternal deaths due to obstetric haemorrhage in South Africa (SA). OBJECTIVE. To compare oxytocin alone with oxytocin + ergometrine in terms of primary prophylaxis for PPH at the time of CS. METHODS. This was a double-blind randomised controlled interventional study comparing oxytocin with oxytocin + ergometrine administered during CS. Patients were randomised to receive oxytocin alone intravenously as a bolus or oxytocin + ergometrine intramuscularly, with the placebo being an injection of sterile water. The study population consisted of women undergoing CS at Kalafong Provincial Tertiary Hospital in Atteridgeville, Gauteng, SA. RESULTS. Five hundred and forty women were randomised and data for 416 women, of whom 214 received oxytocin and 202 oxytocin + ergometrine, were available for analysis. In the oxytocin group 19 women (8.9%) required blood transfusion, compared with seven (3.5%) in the oxytocin + ergometrine group (p=0.01; relative risk = 2.78; 95% confidence interval 1.21 - 6.4). There were no statistically significant differences in the mean estimated visual and mean calculated blood loss. CONCLUSIONS. The overall need for blood transfusion was significantly reduced by about two-thirds in women receiving the oxytocin + ergometrine combination. Consideration should be given to using oxytocin + ergometrine for prophylaxis of PPH at CS.http://www.samj.org.zaam2016Obstetrics and Gynaecolog

    Estudio piloto del modelo técnico de ejecución del pitch a captura de pies en gimnasia acrobática

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    En Gimnasia Acrobática (GA) el Toe Pitch to Catch (TPC) es una acción técnica muy usual, lo que motiva la necesidad de proporcionar un modelo técnico del movimiento que permita facilitar la compresión de los factores relacionados con su ejecución. Se analizaron 12 ejecuciones sin penalizaciones técnicas realiza- das por una pareja mixta de GA utilizando técnicas de fotogrametría y dinamometría. Para el análisis se dividió el movimiento en tres fases: Impulsión, Vuelo y Recepción. Los resultados indicaron que el valor máximo de fuerza en la Fase de Impulsión fue de 2,67 ± 0,06 BW (PC: Peso Corporal, BW: Body Weigth) mientras que en la de Recepción fue de 2,78 ± 0,30 PC: Peso Corporal. En el modelo técnico individual analizado se destaca cómo en la Fase de Impulsión es más importante optimizar el impulso aplicado que la fuerza máxima. Durante la Fase de Vuelo, sobresale la alta reproducibilidad en los intentos satisfactorios de la altura alcanzada por el Top para facilitar su posterior recepción. Finalmente durante la Fase de Recepción, se destaca la acción de frenado del Base con el fin de minimizar las fuerzas de reacción verticales del suelo en los movimientos de recepción del Top.Centro de Investigación en Rendimiento Físico y Deportiv

    The additive effect of adherence to multiple healthy lifestyles on subclinical atherosclerosis: Insights from the AWHS

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    Background: Public health strategies targeting multiple healthy behaviors, rather than individual factors, have been proposed as more efficient strategies to promote cardiovascular health. However, the additive effect of multiple targets on primary prevention has not been fully characterized. Objective: To examine how adherence to multiple healthy behaviors is associated with the presence of subclinical atherosclerosis, a measure of early cardiovascular disease. Methods: Analysis of a baseline data from 1798 middle-aged men from the Aragon Workers Health Study conducted between 2009 and 2010. Healthy behaviors were defined according to American Heart Association recommendations, aligned with Spanish Nutritional recommendations and included moderate alcohol consumption, smoking abstinence, no abdominal adiposity, decreased sedentarism, and adherence to Alternate Mediterranean Dietary Index. Presence of coronary artery calcium and plaques in femoral and carotid was quantified by a 16-slice computed tomography scanner and 2D ultrasound. Results: Moderate alcohol consumption, as well as adherence to Mediterranean diet is independently associated with a 6% lower risk of having subclinical atherosclerosis. Smoking abstinence is associated with a 11% lower risk of subclinical atherosclerosis. Those who follow 3 lifestyle behaviors (Mediterranean diet, nonsmoking, and moderate alcohol intake) have 18% lower odds of presenting subclinical atherosclerosis compared with those who do not follow these protective lifestyle habits. Conclusion: Adoption of multiple healthy lifestyle behaviors early in life could be a key strategy to tackle the onset of atherosclerosis and reduce cardiovascular disease burden
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