1,182 research outputs found

    Outflows at the Edges of an Active Region in a Coronal Hole: A Signature of Active Region Expansion?

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    Outflows of plasma at the edges of active regions surrounded by quiet Sun are now a common observation with the Hinode satellite. While there is observational evidence to suggest that the outflows are originating in the magnetic field surrounding the active regions, there is no conclusive evidence that reveals how they are driven. Motivated by observations of outflows at the periphery of a mature active region embedded in a coronal hole, we have used a three-dimensional simulation to emulate the active region's development in order to investigate the origin and driver of these outflows. We find outflows are accelerated from a site in the coronal hole magnetic field immediately surrounding the active region and are channelled along the coronal hole field as they rise through the atmosphere. The plasma is accelerated simply as a result of the active region expanding horizontally as it develops. Many of the characteristics of the outflows generated in the simulation are consistent with those of observed outflows: velocities up to 45 km per sec, properties akin to the coronal hole, proximity to the active region's draining loops, expansion with height, and projection over monopolar photospheric magnetic concentrations. Although the horizontal expansion occurs as a consequence of the active region's development in the simulation, expansion is also a general feature of established active regions. Hence, it is entirely possible and plausible that the expansion acceleration mechanism displayed in the simulation is occurring in active regions on the Sun and, in addition to reconnection, is driving the outflows observed at their edges.Comment: 19 pages, 9 figure

    Impact of Tandem Repeats on the Scaling of Nucleotide Sequences

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    Techniques such as detrended fluctuation analysis (DFA) and its extensions have been widely used to determine the nature of scaling in nucleotide sequences. In this brief communication we show that tandem repeats which are ubiquitous in nucleotide sequences can prevent reliable estimation of possible long-range correlations. Therefore, it is important to investigate the presence of tandem repeats prior to scaling exponent estimation.Comment: 14 Pages, 3 Figure

    Is Religion Undermined By Evolutionary Arguments?

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    I examine three major antireligious arguments that are often proposed in various forms by cognitive and evolutionary scientists, and indicate possible responses to them. A fundamental problem with the entire debate arises because the term "religion" is too vague. So I reformulate the debate in terms of a less vague central concept: faith. Referring mainly to Aquinas on faith, I proceed by evaluating how the previously mentioned cognitive and evolutionary arguments fare when dealing with faith. The results show that some aspects of the concept of faith are in principle beyond the range of evolutionary explanation and some other aspects are not. Nevertheless, an evolutionary account merges smoothly with faith’s theological dimension

    Localização de lesões (úlceras e/ou erosões) e descamações da mucosa gástrica em potros assintomáticos da raça Quarto de Milha: estudo endoscópico

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    A úlcera gástrica figura como uma importante causa de desconforto abdominal em eqüinos jovens. De acordo com a localização das lesões na mucosa gástrica, a presença ou ausência de sinais clínicos e possíveis complicações resultantes de sua ocorrência, quatro síndromes clínicas são freqüentemente descritas em potros: 1) Úlceras assintomáticas ou silenciosas; 2) Úlceras sintomáticas ou ativas; 3) Úlceras perfuradas; e 4) Obstruções gástrica ou duodenal. Com o objetivo de se verificar a distribuição de lesões gástricas (úlceras e/ou erosões) e descamações do epitélio aglandular no estômago de eqüinos jovens assim como uma possível relação entre as alterações mencionadas (lesão/descamação) sessenta potros da raça Quarto de Milha não-portadores de sinais clínicos compatíveis com úlceras gástricas foram submetidos à gastroscopia. Os potros foram divididos em quatro faixas etárias de 15 animais cada uma, sendo: 1 a 30 dias, 31 a 60 dias, 61 a 90 dias e 91 a 120 dias de idade. As lesões ocorreram em ordem decrescente de freqüência nas regiões aglandular próximo ao margo plicatus ao longo da curvatura maior, aglandular próximo à cárdia ao longo da curvatura menor, fundo glandular e aglandular e antro. As descamações do epitélio aglandular ocorreram de forma similar nas regiões de fundo e margo plicatus. Não houve associação entre a ocorrência de lesões e descamações.Gastric ulcer accounts for an important cause of abdominal discomfort in young horses. Concerning either the presence or absence of clinical signs and their variations, the lesions location in the gastric mucosa and complications resulting from ulcerative lesions, four clinical syndromes have been described in foals: 1) Asymptomatic or silent ulcers; 2) Symptomatic or active ulcers; 3) Perforated ulcers; and 4) Gastric or duodenal obstruction. With the aim of studying the distribution of lesions (ulcers and/or erosions) and desquamations from the non-glandular epithelium in the gastric mucosa of young horses and a possible relationship between both alterations (lesion/desquamation), sixty Quarter Horse foals without signs of gastric disease underwent gastroscopy. Foals were divided by age in four groups of 15 animals as follows: 1 to 30 days, 31 to 60 days, 61 to 90 days and 91 to 120 days. Lesions were most prevalent in the stratified squamous epithelial mucosa mainly adjacent to the margo plicatus along the greater curvature followed by squamous mucosa next to the cardia along the lesser curvature, glandular and non-glandular fundus and antrum. Regions of the fundus and margo plicatus were similarly affected by desquamations. There was no association between lesions and desquamations occurrence

    Prevalência de lesões gástricas (úlceras e/ou erosões) e sua relação com possíveis fatores estressantes em potros assintomáticos da raça Quarto de Milha: estudo endoscópico

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    Gastric ulcer accounts for one of the most important causes of abdominal discomfort in young horses. With the aim of studying the prevalence of lesions (ulcers and/or erosions) and their relationship to factors such as stress, age and sex, sixty quarter horse foals without signs of gastric disease underwent gastroscopy. Foals were divided into four age groups of 15 animals as follows: 1 to 30 days, 31 to 60 days, 61 to 90 days and 91 to 120 days. The prevalence of gastric lesions was 43.3%. Foals aged 61 to ninety days were the most affected (nine of 15). There were no significant differences between ages. Squamous epithelial exfoliation was observed in nine foals (60%) less than thirty days, in six (40%) between 31 to sixty days and only in two foals (6.6%) older than sixty days. Factors regarded as stressful such as high tick infestation (29), respiratory problems (3), skin diseases (3), babesiosis (2), umbilical thickening (1), diarrhea (1), orthopedic problems (1) and laceration with fly larvae (1) had no relationship with lesions. No difference in prevalence by sex was noted.A úlcera gástrica constitui-se numa das mais importantes causas de desconforto abdominal em eqüinos jovens. Com o objetivo de se verificar a prevalência de lesões gástricas (úlceras e/ou erosões) e sua relação com fatores como estresse, idade, e sexo, sessenta potros da raça Quarto de Milha não portadores de sinais clínicos compatíveis com lesões gástricas foram submetidos à gastroscopia. Os potros foram divididos em quatro faixas etárias de 15 animais cada uma, sendo: 1 a 30 dias, 31 a 60 dias, 61 a 90 dias e 91 a 120 dias de idade. A prevalência de lesões gástricas foi de 43,3%. Animais com idade entre 61 a noventa dias foram os mais acometidos. Não houve diferença significativa entre as faixas etárias. Descamações do epitélio aglandular ocorreram em nove potros (60%) entre um e trinta dias, em seis (40%) entre 31 e sessenta dias e em apenas dois (6,6%) com idade superior a sessenta dias. Fatores considerados estressantes, como infestação intensa por carrapatos (29), problemas respiratórios (3), dermatopatias (3), babesiose (2), onfaloflebite (1), diarréia (1), problemas ortopédicos (1) e ferida lacerante com presença de miíase (1) não influenciaram a ocorrência das lesões. Machos e fêmeas foram igualmente acometidos

    Important criteria for measuring heritage building condition

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    The excellence condition of a heritage building lies not only in the appearance of its individual elements, but also in the integrity of all its components, considered as unique criteria of the specific construction technology of its time and place. However, these criteria are varied and not specific. Therefore, this study aimed to identify and rank the important criteria for measuring the condition of heritage buildings in Malaysia. Data obtained through questionnaire and analyzed using Average Index (AI) in order to establish the important criteria. Samples were selected from a panel of experts in the field of heritage buildings management including industry players and academicians. The established criteria will be used as components to develop a new method of heritage building condition determination model in Malaysia

    Evidence of Twisted flux-tube Emergence in Active Regions

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    Elongated magnetic polarities are observed during the emergence phase of bipolar active regions (ARs). These extended features, called magnetic tongues, are interpreted as a consequence of the azimuthal component of the magnetic flux in the toroidal flux-tubes that form ARs. We develop a new systematic and user-independent method to identify AR tongues. Our method is based on determining and analyzing the evolution of the AR main polarity inversion line (PIL). The effect of the tongues is quantified by measuring the acute angle [ tau] between the orientation of the PIL and the direction orthogonal to the AR main bipolar axis. We apply a simple model to simulate the emergence of a bipolar AR. This model lets us interpret the effect of magnetic tongues on parameters that characterize ARs ( e.g. the PIL inclination and the tilt angles, and their evolution). In this idealized kinematic emergence model, tau is a monotonically increasing function of the twist and has the same sign as the magnetic helicity. We systematically apply our procedure to a set of bipolar ARs that were observed emerging in line-of-sight magnetograms over eight years. For most of the cases studied, the tongues only have a small influence on the AR tilt angle since tongues have a much lower magnetic flux than the more concentrated main polarities. From the observed evolution of tau, corrected for the temporal evolution of the tilt angle and its final value when the AR is fully emerged, we estimate the average number of turns in the subphotospherically emerging flux-rope. These values for the 41 observed ARs are below unity, except for one. This indicates that subphotospheric flux-ropes typically have a low amount of twist, i.e. highly twisted flux-tubes are rare. Our results demonstrate that the evolution of the PIL is a robust indicator of the presence of tongues and constrains the amount of twist in emerging flux-tube
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