3,676 research outputs found

    Wolf spiders (Araneae: Lycosidae) on the overgrowing peat bog in Dubravica (north-western Croatia)

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    The peat bog in Dubravica is of spread interest due to its overgrowing by the process of natural succession, causing the habitat to become dryer and shadier. The dominance structure and phenology of wolf spiders on the Dubravica bog was studied. The spiders were collected during the period 09.04.-9.10.1995, using 20 pitfall traps. Altogether 10 lycosid species were found among 723 adult individuals. For six more abundant species phenology graphs are presented. Three species are found to be eudominant: Pardosa lugubris, Trochosa spinipalpis and Hygrolycosa rubrofasciata. The lycosids habitat preferences and dominance structure according the habitat condition and species occurrences on some other European bogs are discussed. 55,2 % caught specimens are hygrophilous species, and only 7,6 % are photophilous. The lycosid fauna and dominance structure does reflect the habitat condition. As overgrowing is not fully progressed yet, the lycosid fauna of this bog is still relatively bog-characteristic

    Weak lensing study of Abell 2029

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    Abell 2029 is one of the most studied clusters due to its proximity (z=0.07), its strong X-ray brightness and its giant cD galaxy which is one of the biggest stellar aggregates we know. We present here the first weak lensing mass reconstruction of this cluster made from a deep I-band image of 28.5'x28.5' centered on the cluster cD galaxy. This preliminary result allows us already to show the shape similarities between the cD galaxy and the cluster itself, suggesting that they form actually a single structure. We find a lower estimate of the total mass of 1.8 10^14 h^-1 solar masses within a radius of 0.3 h^-1 Mpc. We finally compute the mass-to-cD-light ratio and its evolution as a function of scale.Comment: 5 pages, to appear in the proceedings of "Matter and Energy in Clusters of Galaxies", ASP Conference Serie

    The dark clump near Abell 1942: dark matter halo or statistical fluke?

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    Weak lensing surveys provide the possibility of identifying dark matter halos based on their total matter content rather than just the luminous matter content. On the basis of two sets of observations carried out with the CFHT, Erben et al. (2000) presented the first candidate dark clump, i.e. a dark matter concentration identified by its significant weak lensing signal without a corresponding galaxy overdensity or X-ray emission. We present a set of HST mosaic observations which confirms the presence of an alignment signal at the dark clump position. The signal strength, however, is weaker than in the ground-based data. It is therefore still unclear whether the signal is caused by a lensing mass or is just a chance alignment. We also present Chandra observations of the dark clump, which fail to reveal any significant extended emission. A comparison of the ellipticity measurements from the space-based HST data and the ground-based CFHT data shows a remarkable agreement on average, demonstrating that weak lensing studies from high-quality ground-based observations yield reliable results.Comment: 33 pages, 34 figures, submitted to A&A. Version with full resolution figures available at http://www.mpa-garching.mpg.de/~anja/aaclump.pd

    Towards a new settlement in Australian teacher education : a review of shifting sensibilities

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    This essay reviews and provides a critical introduction to the papers found within these Refereed Proceedings of the Australian Teacher Education Association (ATEA) Conference held in Yeppoon, Queensland, 5-8 July, 1997. It argues that within Australia, and to a lesser extent the Asia Pacific region, there is evidence of a new settlement in teacher education, the parameters and particulars of which are characterised by significant changes in its political economy, social and knowledge bases. While it is evident that particular features of previous settlements in Australian teacher education remain, in recent times many of these features have acquired different emphases and meanings; in part due to their conjoining with and (re)positioning amongst other elements previously illegitimated or `held at bay\u27. Each of the themes of change is examined in turn and, at relevant junctures, references are made to papers within the volume that provide further illustration and explanation

    Searching dark-matter halos in the GaBoDS survey

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    We apply the linear filter for the weak-lensing signal of dark-matter halos developed in Maturi et al. (2005) to the cosmic-shear data extracted from the Garching-Bonn-Deep-Survey (GaBoDS). We wish to search for dark-matter halos through weak-lensing signatures which are significantly above the random and systematic noise level caused by intervening large-scale structures. We employ a linear matched filter which maximises the signal-to-noise ratio by minimising the number of spurious detections caused by the superposition of large-scale structures (LSS). This is achieved by suppressing those spatial frequencies dominated by the LSS contamination. We confirm the improved stability and reliability of the detections achieved with our new filter compared to the commonly-used aperture mass (Schneider, 1996; Schneider et al., 1998) and to the aperture mass based on the shear profile expected for NFW haloes (see e.g. Schirmer et al., 2004; Hennawi & Spergel, 2005). Schirmer et al.~(2006) achieved results comparable to our filter, but probably only because of the low average redshift of the background sources in GaBoDS, which keeps the LSS contamination low. For deeper data, the difference will be more important, as shown by Maturi et al. (2005). We detect fourteen halos on about eighteen square degrees selected from the survey. Five are known clusters, two are associated with over-densities of galaxies visible in the GaBoDS image, and seven have no known optical or X-ray counterparts.Comment: 8 pages, 4 figures, accepted by A&

    The teacher educator as (re)negotiated professional: critical incidents in steering between state and market in Australia

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    [Abstract]: A dominant discourse in western higher education circles is currently concerned – even obsessed – with the marketisation of knowledge as a commodity to be purchased and traded (Healy, 1998; Poole, 1998; Richardson, 1998). These developments are broadly allied with managerial changes that some have called ‘steering at a distance’ (Kickert, 1991; Marceau, 1993), whereby the impact of the state on individual higher education workers is maintained and intensified at the same time that pressure is applied to ‘wean’ universities from government funding. This paper explores a different kind of ‘steering’, the kind that is being engaged by Australian teacher educators confronted by developing competitiveness in higher education. We argue that these changes compel teacher educators to (re)negotiate their professionalisms; to re-examine their attitudes towards, and values within, education and its practices as they (individually and collectively) steer new courses through the state and the market. We illustrate our argument by referring to three critical incidents in the professional lives of teacher educators located within a globalised, multi-campus and provincial Australian university, yet with important implications also for teacher educators outside Australia. We posit the (re)negotiated professionalisms manifested in those incidents as a few among several potential kinds of steering by Australian teacher educators

    GaBoDS: The Garching-Bonn Deep Survey -- IX. A sample of 158 shear-selected mass concentration candidates

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    The aim of the present work is the construction of a mass-selected galaxy cluster sample based on weak gravitational lensing methods. This sample will be subject to spectroscopic follow-up observations. We apply the mass aperture statistics and a derivative of it to 19 square degrees of high quality, single colour wide field imaging data obtained with the WFI@MPG/ESO 2.2m telescope. For the statistics a family of filter functions is used that approximates the expected tangential radial shear profile and thus allows for the efficient detection of mass concentrations. We identify 158 possible mass concentrations. This is the first time that such a large and blindly selected sample is published. 72 of the detections are associated with concentrations of bright galaxies. For about 22 of those we found spectra in the literature, indicating or proving that the galaxies seen are indeed spatially concentrated. 15 of those were previously known to be clusters or have meanwhile been secured as such. We currently follow-up a larger number of them spectroscopically to obtain deeper insight into their physical properties. The remaining 55% of the possible mass concentrations found are not associated with any optical light, or could not be classified unambiguously. We show that those "dark" detections are to a significant degree due to noise, and appear preferentially in shallow data.Comment: 25 pages, 18 figures, submitted to A&A; for a better print version, see http://www.astro.uni-bonn.de/~mischa/astroph_0607022.pd

    Towards extracting the timelike pion form factor on CLS two-flavour ensembles

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    Results are presented from an ongoing study of the ρ\rho resonance. The focus is on CLS 2-flavour ensembles generated using O(a)\mathcal{O}(a) improved Wilson fermions with pion masses ranging from 265265 to 437437 MeV\mathrm{MeV}. The energy levels are extracted by solving the GEVP of correlator matrices, created with the distillation approach involving ρ\rho and ππ\pi\pi interpolators. The study is done in the centre-of-mass frame and several moving frames. One aim of this work is to extract the timelike pion form factor after applying the L\"uscher formalism. We therefore plan to integrate this study with the existing Mainz programme for the calculation of the hadronic vacuum polarization contribution to the muon g−2g-2.Comment: proceedings to conference: Lattice 2017, Granada, Spai

    Effects of whey protein concentrate on shelf life of cookies using corn and sunflower oils

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    The objective of this work was to study the effect of whey protein concentrate (WPC) on shelf life of cookies using corn and sunflower oils as fat source. Wheat flour was partially replaced by WPC with levels of 5, 7.5, 10 and 15 %. A User Defined Design was used and the three following responses were measured: peroxide index (meqO2/kg), flavour (score from 1-10) and rancidity (detectable and non-detectable) at 0, 7, 14, 21 and 70 days of storage. Results show that during storage peroxide index (PI) increases in all cookies samples. However a significant decrease was found when corn oil was used instead of sunflower oil and when the level of WPC goes from 0% to 15%. Regarding sensory evaluation, all cookies were evaluated as acceptable (scored flavour ≄ 6) and no rancid flavour was perceived, except for two samples which were assigned with 5 and rancid flavour was considered as detectable; these samples correspond to cookies evaluated at day 70, elaborated with sunflower oil and the lowest dose of WPC. No significant differences were found in cookies flavour prepared with different oils. On the other hand and relative to the level of WPC replacement, differences were found by the panel at days 0 and 7, a reduction in assigned score when WPC dose was increased, however this difference was not significant in the subsequent assessment days. According to research results, an increase in stability was clearly obtained in cookies elaborated with corn oil and the highest concentration of WPC.Fil: Erben, Melina. Universidad Nacional del Litoral. Facultad de IngenierĂ­a QuĂ­mica. Instituto de TecnologĂ­a de los Alimentos; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe; ArgentinaFil: Sanchez, Hugo Diego. Universidad Nacional del Litoral. Facultad de IngenierĂ­a QuĂ­mica. Instituto de TecnologĂ­a de los Alimentos; ArgentinaFil: Osella, Carlos Alberto. Universidad Nacional del Litoral. Facultad de IngenierĂ­a QuĂ­mica. Instituto de TecnologĂ­a de los Alimentos; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe; Argentin

    Reasons for Divorce: Perspectives of Divorced Seventh-day Adventists (The First Draft of an Article)

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    This paper reports a research on perspectives of divorced Seventh-day Adventists. The population of this project was composed of all Seventh-day Adventist divorcees residing in the U.S. that were included on the mailing list of Adventist Singles Ministries in February 1993. A questionnaire was used to gather the data.https://digitalcommons.andrews.edu/hrsa/1025/thumbnail.jp
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