Antiferromagnetic resonance in ferroborate NdFe3_3(BO3_3)$_4

The AFMR spectra of the NdFe$_3$(BO$_3$)$_4$ crystal are measured in a wide range of frequencies and temperatures. It is found that by the type of magnetic anisotropy the compound is an "easy-plane" antiferromagnet with a weak anisotropy in the basal plane. The effective magnetic parameters are determined: anisotropy fields $H_{a1}$=1.14 kOe and $H_{a2}$=60 kOe and magnetic excitation gaps $\Delta\nu_1$=101.9 GHz and $\Delta \nu_2$=23.8 GHz. It is shown that commensurate-incommensurate phase transition causes a shift in resonance field and a considerable change in absorption line width. At temperatures below 4.2 K nonlinear regimes of AFMR excitation at low microwave power levels are observed

Water intake, faecal output and intestinal motility in horses moved from pasture to a stabled management regime with controlled exercise

Reasons for performing study: A change in management from pasture to stabling is a risk factor for equine colic. Objectives: To investigate the effect of a management change from pasture with no controlled exercise to stabling with light exercise on aspects of gastrointestinal function related to large colon impaction. The hypothesis was that drinking water intake, faecal output, faecal water content and large intestinal motility would be altered by a transition from a pastured to a stabled regime. Study design: Within-subject management intervention trial involving changes in feeding and exercise using noninvasive techniques. Methods: Seven normal horses were evaluated in a within-subjects study design. Horses were monitored while at pasture 24 h/day, and for 14 days following a transition to a stabling regime with light controlled exercise. Drinking water intake, faecal output and faecal dry matter were measured. Motility of the caecum, sternal flexure and left colon (contractions/min) were measured twice daily by transcutaneous ultrasound. Mean values were pooled for the pastured regime and used as a reference for comparison with stabled data (Days 1–14 post stabling) for multilevel statistical analysis. Results: Drinking water intake was significantly increased (mean ± s.d. pasture 2.4 ± 1.8 vs. stabled 6.4 ± 0.6 l/100 kg bwt/day), total faecal output was significantly decreased (pasture 4.62 ± 1.69 vs. stabled 1.81 ± 0.5 kg/100 kg bwt/day) and faecal dry matter content was significantly increased (pasture 18.7 ± 2.28 vs. stabled 27.2 ± 1.93% DM/day) on all days post stabling compared with measurements taken at pasture (P<0.05). Motility was significantly decreased in all regions of the large colon collectively on Day 2 post stabling (-0.76 contractions/min), and in the left colon only on Day 4 (-0.62 contractions/min; P<0.05). Conclusions: There were significant changes in large intestinal motility patterns and parameters relating to gastrointestinal water balance during a transition from pasture to stabled management, particularly during the first 5 days

Understanding and responding to COVID-19 in Wales: protocol for a privacy-protecting data platform for enhanced epidemiology and evaluation of interventions

INTRODUCTION: The emergence of the novel respiratory SARS-CoV-2 and subsequent COVID-19 pandemic have required rapid assimilation of population-level data to understand and control the spread of infection in the general and vulnerable populations. Rapid analyses are needed to inform policy development and target interventions to at-risk groups to prevent serious health outcomes. We aim to provide an accessible research platform to determine demographic, socioeconomic and clinical risk factors for infection, morbidity and mortality of COVID-19, to measure the impact of COVID-19 on healthcare utilisation and long-term health, and to enable the evaluation of natural experiments of policy interventions. METHODS AND ANALYSIS: Two privacy-protecting population-level cohorts have been created and derived from multisourced demographic and healthcare data. The C20 cohort consists of 3.2 million people in Wales on the 1 January 2020 with follow-up until 31 May 2020. The complete cohort dataset will be updated monthly with some individual datasets available daily. The C16 cohort consists of 3 million people in Wales on the 1 January 2016 with follow-up to 31 December 2019. C16 is designed as a counterfactual cohort to provide contextual comparative population data on disease, health service utilisation and mortality. Study outcomes will: (a) characterise the epidemiology of COVID-19, (b) assess socioeconomic and demographic influences on infection and outcomes, (c) measure the impact of COVID-19 on short -term and longer-term population outcomes and (d) undertake studies on the transmission and spatial spread of infection. ETHICS AND DISSEMINATION: The Secure Anonymised Information Linkage-independent Information Governance Review Panel has approved this study. The study findings will be presented to policy groups, public meetings, national and international conferences, and published in peer-reviewed journals

Saturn Atmospheric Structure and Dynamics

2 Saturn inhabits a dynamical regime of rapidly rotating, internally heated atmospheres similar to Jupiter. Zonal winds have remained fairly steady since the time of Voyager except in the equatorial zone and slightly stronger winds occur at deeper levels. Eddies supply energy to the jets at a rate somewhat less than on Jupiter and mix potential vorticity near westward jets. Convective clouds exist preferentially in cyclonic shear regions as on Jupiter but also near jets, including major outbreaks near 35°S associated with Saturn electrostatic discharges, and in sporadic giant equatorial storms perhaps generated from frequent events at depth. The implied meridional circulation at and below the visible cloud tops consists of upwelling (downwelling) at cyclonic (anti-cyclonic) shear latitudes. Thermal winds decay upward above the clouds, implying a reversal of the circulation there. Warm-core vortices with associated cyclonic circulations exist at both poles, including surrounding thick high clouds at the south pole. Disequilibrium gas concentrations in the tropical upper troposphere imply rising motion there. The radiative-convective boundary and tropopause occur at higher pressure in the southern (summer) hemisphere due to greater penetration of solar heating there. A temperature “knee ” of warm air below the tropopause, perhaps due to haze heating, is stronger in the summer hemisphere as well. Saturn’s south polar stratosphere is warmer than predicted by radiative models and enhanced in ethane, suggesting subsidence-driven adiabatic warming there. Recent modeling advances suggest that shallow weather laye

'Conciousness' : un nuevo concepto en psicología social según Charles Reich

The chain reaction failure of a major portion of a structure that is initiated by the failure of a relatively small portion is referred to as the progressive collapse of a structure. The main approach used for the evaluation of a structure’s vulnerability to progressive collapse is the instantaneous removal of a load bearing element of the structure, followed by studying its effect on other structural elements. An analytical study using a finite element model (FEM) is used in this investigation with the aim of comparing the main two standards that address progressive collapse. A three-dimensional nonlinear model of a concrete generic frame structure is used in the study. The structure is designed according to different seismic zones in order to evaluate the effect of the seismic region on its vulnerability to progressive collapse

Estudo do conversor zeta em condu??o simult?nea dos semicondutores aplicada ? alimenta??o de LEDs de pot?ncia

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS ([email protected]) on 2015-06-17T12:02:56Z No. of bitstreams: 1 470517 - Texto Completo.pdf: 3643142 bytes, checksum: 1f5335f433b80cbcbe58f559422c4f72 (MD5)Made available in DSpace on 2015-06-17T12:02:56Z (GMT). No. of bitstreams: 1 470517 - Texto Completo.pdf: 3643142 bytes, checksum: 1f5335f433b80cbcbe58f559422c4f72 (MD5) Previous issue date: 2015-01-07Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPESThis work presents the simultaneous conduction mode (SCM), which is applied to the operation of the Zeta converter. This mode has the ability to implement an ideal power factor corrector (PFC) employing only one feedback control loop. In SCM, the current in the main switch and in the diode flows simultaneously within one of the operation stages. In SCM, the power converter presents characteristics of both conduction modes: continuous conduction mode (CCM) and discontinuous conduction mode (DCM). In SCM, the currents in the inductors of the power converter are never nullified, which is a typical behavior of the CCM. Nevertheless, the SCM does that while obtaining an ideal PFC with just one control loop. The SCM maintains its features, regardless of its control variable being the output current or the output voltage of the power converter. The solely application of a fixed duty cycle controller is enough to attain all these advantages, which is usually a feature of the DCM for PFCs of the flyback family. In order to validate the proposed technique, a complete study of the Zeta converter working in this new operation mode was performed.This study has included a qualitative and a quantitative power converter analysis. These analyses resulted in the development of a design methodology for the Zeta power converter working as a PFC in the SCM. In order to validate the present study, a prototype of the Zeta PFC for operation in the SCM was designed and built. This prototype was developed, as a case of study, to drive a power LED lamp (180?W). Thus, it was obtained the desired experimental confirmation for the research. The main advantage of the SCM, in comparison to the CCM, lies in its ability to maintain the input current of the PFC sinusoidal and in phase with the input voltage, which is imposed by the mains through the use of just a single PWM controller with fixed duty cycle. These results have, also, shown that the current peaks in the main semiconductors of the power converter are lower than their respective values in the DCM. However, this new operation mode results in the increase of the voltages on the main switch and diode in relation to the conventional power converter operation. The research of the application of the proposed method to other power converters is suggested to further works.Este trabalho prop?e a opera??o do conversor Zeta no modo de condu??o simult?nea (MCS), cujo interesse reside na capacidade de implementa??o de um pr?-regulador do fator de pot?ncia (PFP) ideal empregando apenas um la?o de realimenta??o. Quando o conversor trabalha no MCS, a chave principal e o diodo conduzem simultaneamente em um de seus est?gios de opera??o. Neste modo de condu??o, o conversor est?tico apresenta caracter?sticas de ambos os modos de condu??o conhecidos at? agora: o modo de condu??o cont?nua (MCC) e o modo de condu??o descont?nua (MCD). A opera??o no MCS resulta em um conversor est?tico operando como se estivesse no MCC, uma vez que a corrente nos indutores nunca se anula. Embora mantenha o conversor est?tico trabalhando com esta caracter?stica do MCC, o MCS permite a obten??o de um comportamento quase ideal do PFP, utilizando apenas um ?nico controlador, seja ele de corrente ou de tens?o, o qual mant?m a raz?o c?clica do conversor constante, assim como usualmente ocorre com os PFPs da fam?lia redutor-elevador quando operam no MCD.Visando validar esta t?cnica, foi realizado um estudo do conversor operando desta forma que incluiu o desenvolvimento das an?lises qualitativa e quantitativa do conversor, as quais culminaram na elabora??o de uma metodologia de projeto. Assim, realizou-se o projeto de um PFP, baseado no conversor Zeta, para energizar uma lumin?ria LED de 180 W, operando no MCS, como estudo de caso. A lumin?ria utilizada ? o modelo High Power LED Baylight da empresa Luckysunny?. Os resultados obtidos experimentalmente validaram a estrat?gia proposta, uma vez que, com a opera??o do conversor Zeta no MCS reduz-se a ondula??o (ripple) da corrente nos semicondutores em rela??o ? opera??o no MCD. A principal vantagem da opera??o no MCS reside no fato deste manter a corrente de entrada do PFP senoidal em fase com a tens?o imposta pela rede el?trica com apenas uma malha de controle da vari?vel de sa?da de interesse seja ela tens?o ou corrente como no estudo de caso em quest?o. Isto reduz o custo e a complexidade do controlador do conversor. Entretanto, esta estrat?gia apresenta sobretens?o na chave principal e no diodo como principal desvantagem. Sugere-se a investiga??o da aplica??o da metodologia de projeto proposta a outros conversores