2,923 research outputs found

    Permian 40Ar/39Ar ages for post-Variscan minor intrusions in the Iberian Range and Spanish Central System

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    40Ar/39Ar dating of biotite from a calc-alkaline gabbro stock NW of Loscos in the Iberian Range yielded a slightly disturbed gas release spectrum. It has an early Permian, 288.5 ± 1.4 Ma total gas age, interpreted as the minimum emplacement age. The 40Ar/39Ar apparent age of the gabbro agrees with the Autunian stratigraphic age of related volcanic rocks. 40Ar/39Ar step-heating dating of amphibole phenocrysts from an alkaline camptonite dyke ca. 4 km SE of El Hoyo de Pinares in the Sierra Guadarrama sector of the Spanish Central System yielded a mid-Permian 264 ± 3 Ma plateau age, interpreted as the emplacement age. The age is indistinguishable from published 40Ar/39Ar amphibole ages for N-S trending camptonite dykes from the western, Sierra de Gredos segment of the Central System. This suggests that the camptonite dykes from both sectors belong to the same generation

    Milieuverliezen Aver Heino binnen de perken

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    Het project 'Echt Overijssel!' streeft naar een grote rijkdom aan planten- en diersoorten op en rond landbouwgronden, regionaal gesloten grondstofkringlopen en nieuwe economische dragers voor het landelijk gebied. Voor Aver Heino, het proefbedrijf voor biologische melkveehouderij, wordt berekend wat de milieueffecten zijn van het betrekken van meer grondstoffen uit de eigen regio

    Лечение артериальной гипертензии в преклонном возрасте: от отрицания до признания необходимости

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    Представлен анализ результатов клинических исследований антигипертензивной терапии у пожилых пациентов, позволяющий сделать заключение о целесообразности ее проведения даже после достижения 80−летнего возраста.The analysis of the findings of clinical research of antihypertensive therapy in elderly patients, which allowed to conclude about the necessity about the expediency of its administration even in patients over 80, is presented

    Electric Dipole Radiation from Spinning Dust Grains

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    We discuss the rotational excitation of small interstellar grains and the resulting electric dipole radiation from spinning dust. Attention is given to excitation and damping of rotation by: collisions with neutrals; collisions with ions; plasma drag; emission of infrared radiation; emission of microwave radiation; photoelectric emission; and formation of H_2 on the grain surface. We introduce dimensionless functions F and G which allow direct comparison of the contributions of different mechanisms to rotational drag and excitation. Emissivities are estimated for dust in different phases of the interstellar medium, including diffuse HI, warm HI, low-density photoionized gas, and cold molecular gas. Spinning dust grains can explain much, and perhaps all, of the 14-50 GHz background component recently observed in CBR studies. It should be possible to detect rotational emission from small grains by ground-based observations of molecular clouds.Comment: 59 pages, 19 eps figures, uses aaspp4.sty . Submitted to Ap.

    Dutch Adolescents’ Everyday Expressions of Sexual Behavior Trajectories Over a 2-Year Period:A Mixed-Methods Study

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    Using an extended definition of sexuality, this mixed-methods study builds on existing research into adolescents' emergent sexual development by longitudinally examining adolescents' sexual behavior trajectories (i.e., from less to more intimate sexual behavior). Over a 2-year period, 45 adolescents (M age = 15.9 years) reported on their sexual behavior using questionnaires and on their everyday expressions of sexuality in the form of semi-structured diaries. Cluster analysis using the questionnaire data identified three sexual behavior trajectories: a non-sexually active trajectory (meaning no or minor sexual behavior) (n = 29), a gradually sexually active trajectory (meaning step-by-step sexual behavior development) (n = 12), and a fast sexually active trajectory (meaning rapid sexual behavior development) (n = 4). Qualitative analysis using diaries revealed the following themes: romantic versus sex-related topics, desires, uncertainties, and references to the social context. In general, all adolescents reported more about romantic aspects of sexuality (than about sexual acts) in the diaries, regardless of their sexual behavior trajectory. Sexually active adolescents (i.e., gradual and fast) were more concerned with sexuality in their diaries, especially more with the physical aspects of sexuality, than non-active adolescents. Gradual adolescents experienced more desires about physical sexual contact and reported fewer references to their social network than non-active and fast adolescents. The findings suggest that sexual education that discusses the internal experiences of sexuality, such as feelings and thoughts, particularly the romantic aspects, may help adolescents process their preferences for different sexual and romantic acts and may contribute to healthy sexual development

    Visualisation and characterisation of flame radical emissions through intensified spectroscopic imaging

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    Combustion flames contain strong emissions from excited radical species produced by the combustion process. The monitoring and characterisation of such emissions is important for an in-depth understanding of fuel energy conversion and pollutant formation processes. In this paper, an approach combining emission spectroscopy with intensified digital imaging techniques is proposed for visualising and quantifying the radiative characteristics of free radicals of combustion flames. Recent advances in CCD technology, especially in EM image intensification, have made it possible to obtain high resolution emission images of isolated spectral emissions from particular flame radicals. These can be used to study emission intensity and distribution, with the aim of correlating combustion emission products with flame spectral emission patterns

    Tracheospasmolytic activity of vitetrifolin-E isolated from the leaves of Vitex trifolia L.

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    In searching of tracheospasmolytic active compounds from Vitex trifolia, we are now reporting isolation and identification of vitetrifolin-E from active fraction obtained from n-hexane extract of V. trifolia. Vitetrifolin-E blocked spontaneous contraction of male guinea pig trachea induced by histamine and was active in a model using sensitized guinea pig trachea stimulated by ovalbumin. Vitetrifolin-E inhibited tracheal contraction by 22.6% at dose of 1.3 x 10-4 M and by 86.1% at dose of 4.10-4 M. In a model using sensitized male guinea pig trachea, vitetrifolin-E also inhibited the contraction 83.5% (1.3 x 10-5 M).Keywords: vitetrifolin-E, Vitex trifolia, tracheospasmolyti

    Staarthouding voorspelt staartbijten

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    De staarthouding van ongecoupeerde varkens kan een uitbraak van staartbijten voorspellen. Twee tot drie dagen voor een staartbijtuitbraak zijn er minder dieren met een krul in de staart en meer die hun staart tussen de (achter)poten geklemd houden. Dit blijkt uit onderzoek op het Praktijkcentrum Lelysta

    Effect of dexamethasone on fetal hepatic glutamine-glutamate exchange

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    Intravenous infusion of dexamethasone (Dex) in the fetal lamb causes a two- to threefold increase in plasma glutamine and other glucogenic amino acids and a decrease of plasma glutamate to approximately one-third of normal. To explore the underlying mechanisms, hepatic amino acid uptake and conversion of L-[1-(13)C]glutamine to L-[1-(13)C]glutamate and (13)CO(2) were measured in six sheep fetuses before and in the last 2 h of a 26-h Dex infusion. Dex decreased hepatic glutamine and alanine uptakes (P < 0.01) and hepatic glutamate output (P < 0.001). Hepatic outputs of the glutamate (R(Glu,Gln)) and CO(2) formed from plasma glutamine decreased to 21 (P < 0.001) and 53% (P = 0.009) of control, respectively. R(Glu,Gln), expressed as a fraction of both outputs, decreased (P < 0.001) from 0.36 +/- 0.02 to 0.18 +/- 0.04. Hepatic glucose output remained virtually zero throughout the experiment. We conclude that Dex decreases fetal hepatic glutamate output by increasing the routing of glutamate carbon into the citric acid cycle and by decreasing the hepatic uptake of glucogenic amino acids

    Young people's everyday romance and sexual experiences in relation to sex-related conversations with parents:a diary study in the Netherlands

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    This study builds on existing research into how young people's emergent sexual development is connected to parent-child sex-related communication through avoidance vs. disclosure. Over the course of one year, a total of 21 young people (age range 12-17.5) reported in longitudinal qualitative diaries their (1) everyday sexual experiences and (2) sex-related conversations with their parents. Using a mixed-methods approach, findings show that less sexually experienced participants reported greater avoidance of parent-child sex-related conversations than more experienced participants. The sex-related conversations of more experienced participants mainly concerned overt experiences in the form of everyday issues with their romantic partner, while the conversations of less experienced participants were characterised by more covert experiences such as opinions about romantic relationships in general. These results suggest that the degree to which young people feel comfortable talking about sexuality with their parents partly depends on when the conversation takes place during a young person's romantic and sexual development
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