9,216 research outputs found

    Effects of Phosphorus on Benthic Diatom Assemblage Network Structure

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    Ecological network analysis helps identify how relationships among species differ over time and across sets of species. Microbial assemblages are ideal for evaluating changes in species interactions due to environmental changes because they are speciose and respond at multiple scales. To determine how phosphorus limitation influences diatom network structure, I analyzed relationships among 257 species of diatoms from benthic microbial (periphyton) mats from 10 years of annual samples from 136 sites. Expected evidence of changes in network structure in response to periphyton TP were not found, likely due to species replacement with increased TP. Analysis of species connection distributions and the effects of species removal on connections found abundance increases with TP for 32 species with significant roles in network structure, variable abundance for 11 species, and a single species consistently decreased in abundance. This study brings a new methodology of study to the field of ecosystem restoration studies

    Using literature and role-playing to teach social skills to students in self-contained classrooms

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    The purpose of this qualitative research study was to explore the role of educators in teach social skills to self-contained students. Bibliotherapy, which utilizes books to help people solve their problems and role-playing were the two methods used to teach social skills. For this study, five data collection instruments were utilized: audio taped class discussions, video recordings of role-playing sessions, a teacher research journal, an instructional unit, and student projects and artifacts. For the sake of privacy and confidentiality, the names of people and places were altered. The qualitative research study was conducted in a Kindergarten self-contained classroom, located in southern New Jersey. There were eight students in the class who participated in the study. The classifications of the eight students varied. According to the students\u27 IEPs, classifications included multiply disabled, autistic, communication impaired, and multiple sclerosis. In analyzing the data, it became clear that bibliotherapy and roleplaying were effective in teaching students social skills. Implications for using bibliotherapy and role-playing to teach social skills to students in self-contained classrooms are discussed in detail

    A new species of Bolbelasmus Boucomont, 1911 (Insecta Coleoptera Geotrupidae) from Sicily (Italy).

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    Authors have examined all available sicilian specimens belonging to the genus Bolbelasmus, collected between 1893 and 2010, previously identified as B. gallicus e B. unicornis. They conclude that both species have to be excluded from the sicilian fauna and describe the new species B. romanorum, which is characterized by peculiar punctures on the clypeus, the head and the pronotum, and by the shape of the clypeus, the head and the aedeagus sclerites. They compare the new species with all the taxa currently known in the Mediterranean. Further, they show oscillograms of both sexes of the new species, which, as other Bolbelasmus, stridulates vigorously; they also detect for the first time the pars stridens, consisting in a series of small bristles on the lower outer border of wings; the insect emits its sound moving actively the abdomen, the friction of the wing on the first abdominal tergite, particularly swollen, produces the stridulation

    The complex time behaviour of the microquasar GRS 1915+105 in the \rho-class observed with BeppoSAX. III: The hard X-ray delay and limit cycle mapping

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    The microquasar GRS1915+105 was observed by BeppoSAX in October 2000 for about ten days while the source was in \rho-mode, which is characterized by a quasi-regular type I bursting activity. This paper presents a systematic analysis of the delay of the hard and soft X-ray emission at the burst peaks. The lag, also apparent from the comparison of the [1.7-3.4] keV light curves with those in the [6.8-10.2] keV range, is evaluated and studied as a function of time, spectral parameters, and flux. We apply the limit cycle mapping technique, using as independent variables the count rate and the mean photon rate. The results using this technique were also cross-checked using a more standard approach with the cross-correlation methods. Data are organized in runs, each relative to a continuous observation interval. The detected hard-soft delay changes in the course of the pointing from about 3 s to about 10 s and presents a clear correlation with the baseline count rate.Comment: accepted for publication in A&

    Spatial linear stability of a hypersonic shear layer with nonequilibrium thermochemistry

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    We examine the spatial linear stability of a shear layer in a hypervelocity flow where high temperature effects such as chemical dissociation and vibrational excitation are present. A shock triple point is used to generate a free shear layer in a model problem which also occurs in several aerodynamic applications such as shock-boundary layer interaction. Calculations were performed using a state-resolved, three-dimensional forced harmonic oscillator thermochemical model. An extension of an existing molecular-molecular energy transfer rate model to higher collisional energies is presented and verified. Nonequilibrium model results are compared with calculations assuming equilibrium and frozen flows over a range of (frozen) convective Mach numbers from 0.341 to 1.707. A substantial difference in two- and three-dimensional perturbation growth rates is observed among the three models.Thermochemical nonequilibrium has a destabilizing effect on shear-layer perturbations for all convective Mach numbers considered. The analysis considers the evolution of the molecular vibrational quantum distribution during the instability growth by examining the perturbation eigenfunctions. Oxygen and nitrogen preserve a Boltzmann distribution of vibrational energy, while nitric oxide shows a significant deviation from equilibrium. The difference between translational and vibrational temperature eigenfunctions increases with the convective Mach number.Dissociation and vibration transfer effects on the perturbation evolution remain closely correlated at all convective Mach numbers

    Combinations of covariance selections for graphical modelling.

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    We explore the possibility of composing the results of a fixed number of Gaussian graphical model selections on some partially overlapping variables. This appears to be an useful approach in all the research areas where a large amount of data from different sources and types of experiments is available. Therefore the focus is in binding together information coming from heterogeneous studies to improve the understanding of a particular phenomenon of interest. The proposed approach relies on numerical results on artificial and real data
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