1,286 research outputs found

    Organizing to Win: Introduction

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    [Excerpt] The American labor movement is at a watershed. For the first time since the early years of industrial unionism sixty years ago, there is near-universal agreement among union leaders that the future of the movement depends on massive new organizing. In October 1995, John Sweeney, Richard Trumka, and Linda Chavez-Thompson were swept into the top offices of the AFL-CIO, following a campaign that promised organizing at an unprecedented pace and scale. Since taking office, the new AFL-CIO leadership team has created a separate organizing department and has committed $20 million to support coordinated large-scale industry-based organizing drives. In addition, in the summer of 1996, the AFL-CIO launched the Union Summer program, which placed more than a thousand college students and young workers in organizing campaigns across the country

    PSNtools for standalone and web-based structure network analyses of conformational ensembles

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    Structure graphs, in which interacting amino acids/nucleotides correspond to linked nodes, represent cutting-edge tools to investigate macromolecular function. The graph-based approach defined as Protein Structure Network (PSN) was initially implemented in the Wordom software and subsequently in the webPSN server. PSNs are computed either on a molecular dynamics (MD) trajectory (PSN-MD) or on a single structure. In the latter case, information on atomic fluctuations is inferred from the Elastic Network Model-Normal Mode Analysis (ENM-NMA) (PSN-ENM). While Wordom performs both PSN-ENM and PSN-MD analyses but without output post-processing, the webPSN server performs only single-structure PSN-EMN but assisting the user in input setup and output analysis. Here we release for the first time the standalone software PSNtools, which allows calculation and post-processing of PSN analyses carried out either on single structures or on conformational ensembles. Relevant unique and novel features of PSNtools are either comparisons of two networks or computations of consensus networks on sets of homologous/analogous macromolecular structures or conformational ensembles. Network comparisons and consensus serve to infer differences in functionally different states of the same system or network-based signatures in groups of bio-macromolecules sharing either the same functionality or the same fold. In addition to the new software, here we release also an updated version of the webPSN server, which allows performing an interactive graphical analysis of PSN-MD, following the upload of the PSNtools output. PSNtools, the auxiliary binary version of Wordom software, and the WebPSN server are freely available at http://webpsn.hpc.unimo.it/wpsn3.php

    Behavioural inventory of the giraffe (<i>Giraffa camelopardalis</i>)

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    Background Numerous factors like continuous habitat reduction or fragmentation for free-ranging giraffes (Giraffa camelopardalis) as well as e.g. suboptimal housing conditions for animals in captivity might lead to behavioural alterations as part of the overall adaptation process to the changing living conditions. In order to facilitate current and future studies on giraffe behaviour, a comprehensive ethogram was compiled based on existing literature, as well as observations on giraffes in the wild (Hwange National Park, Zimbabwe; Entabeni Game Reserve, South Africa), and in captivity (National Zoological Gardens of South Africa, Pretoria). Findings The resulting ethogram lists 65 different behavioural patterns, which were described and grouped into seven categories: General activities, Abnormal repetitive behaviours, General interactions, Bull-Cow behaviour, Bull-Bull behaviour, Cow-Bull behaviour, Maternal behaviours, and Interactions by calves. The behaviours were further described regarding a presumed purpose, particularly with respect to social interactions and sexual behaviour. Contradictory descriptions from previous studies were considered and discussed in comparison with our own observations. Conclusions This ethogram provides a basis for current and future studies by suggesting a terminology which can be used for harmonizing behavioural observations, thus helping to facilitate comparability of future results. Subsequently, a better understanding of the behavioural ecology of giraffes in the wild as well as in captivity could aid future conservation efforts

    Magnetic characterization of the frustrated three-leg ladder compound [(CuCl2tachH)3Cl]Cl2

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    We report the magnetic features of a new one-dimensional stack of antiferromagnetically coupled equilateral copper(II) triangles. High-field magnetization measurements show that the interaction between the copper triangles is of the same order of magnitude as the intra-triangle exchange although only coupled via hydrogen bonds. The infinite chain turns out to be an interesting example of a frustrated cylindrical three-leg ladder with competing intra- and inter-triangle interactions. We demonstrate that the ground state is a spin singlet which is gaped from the triplet excitation.Comment: 6 pages, 9 figures, revised version submitted to Phys. Rev. B. More information at http://obelix.physik.uni-osnabrueck.de/~schnack

    Modern Determination of Vertical Deflections Using Digital Zenith Cameras

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    At the beginning of the 21st century, a significant technological change took place in geodetic astronomy. In Zurich and Hannover, digital zenith camera systems were developed based on digital imaging sensors (charge-coupled device) that strongly improved the degree of automation, efficiency, and accuracy of the observation of the direction of the plumb line and its vertical deflection. This paper describes the instrumental design of the new digital zenith camera systems and gives an overview of the data processing with focus on the models used for astrometric data reduction and tilt correction. Results of frequently repeated observations of vertical deflections and comparison measurements show an accuracy of vertical deflection measurements of better than 0.1 arc sec. Application examples for vertical deflection data from zenith camera observations, such as the high-precision local gravity field determination in engineering projects and gravity field validation are summarized

    Site amplification estimates in the Garigliano valley, central Italy, based on dense array measurements of ambient noise

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    A frequency-domain formulation of the Aki (1957, 1965) autocorrelation method has been applied to seismic noise recorded by a 100-m wide circular array deployed on soft Holocene sediments in the Garigliano river valley, where a large amplification of ground motion during earthquakes was experienced (Rovelli et al., 1988). The application of this method to ambient noise recordings demonstrates that microtremors in the valley are dispersive and dominated by surface waves. By assuming that the vertical component reflects Rayleigh wave motion, we obtain a dispersion curve that is interpreted in terms of a layered shear-wave velocity structure. Layer thicknesses are constrained by the stratigraphic information provided by a deep hole drilled in the area, and shear velocities are estimated by means of a trial-and-error approach to achieve a satisfactory fit of the ambient noise dispersion. The best-fit velocity model is used to compute a theoretical transfer function, which is then compared with an average spectral ratio obtained from earthquake weak ground motions recorded at two stations, one in the valley and the other on a limestone reference site. An overall agreement is found between the theoretical curve and the observed spectral ratios. The discrepancies that do exist may be ascribed to the assumption of 1-D inhomogeneity which considerably simplifies the theoretical transfer function. Our results show that the spatial-correlation method can be useful to infer velocity structure down to depths of hundreds of meters, when generalized geological informations are available, and can thus provide useful constraints for theoretical methodologies for the prediction of site response

    Bidimensional chronoabsorptometric study of electropolymerisation of 4,4 '-bis(2-methylbutylthio)-2,2 '-bithiophene

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    Bidimensional chronoabsorptometry is a novel spectroelectrochemical technique that monitors simultaneously three different signals: current and absorbance both normal to the electrode plane and parallel to this plane during a time in which a fixed potential is imposed. This technique is applied in the visible range to the study of the electropolymerisation of 4,4'-bis(2-methylbutylthio)2,2'-bithiophene (MBTBT). Experiments are performed in a spectroelectrochemical cell under finite diffusion conditions (thin layer cell) with the aim of interpreting the processes taking place both at the electrode surface and in the adjacent solution during the potentiostatic electrogeneration and deposition of the polymer. Correlations are drawn out among the trends of the oligomers concentration in solution, the polymer electrodeposition and charging, and the current flow, on the time scales of the different steps of the process. (C) 2002 Elsevier Science B.V. All rights reserved

    Suplementación estratégica en una majada Pampinta

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    El objetivo del presente trabajo fue determinar la magnitud de los efectos causados por la suplementación estratégica en los últimos 45 días de gestación sobre algunos de los índices productivos (peso al nacer, sobrevivencia de los corderos, ganancia de peso en el primer mes de vida) en vientres de distinta condición corporal de una majada Pampinta. El ensayo se llevó a cabo en el campo experimental de la Facultad de Agronomía de la Universidad Nacional de La Pampa ubicado a 36° 46´de latitud sur, 64° 16’ de longitud oeste. Se utilizaron 90 vientres de distintas edades de la raza Pampinta. Se realizó servicio durante 21 días por monta natural en el mes de abril. En el momento de realizada la Ecografía se separaron del resto de la majada los vientres preñados. Se midió condición corporal en las madres en tres oportunidades: en la ecografía, en el parto y 38 días posteriores a la fecha media de parición. Para el estudio se utilizó un modelo con dos factores alimentación y condición corporal. El primero con dos niveles, uno pastoreo y el otro pastoreo más suplemento. El segundo factor también con dos niveles, condición corporal baja y, condición corporal alta. Los tratamientos aplicados en las ovejas fueron cuatro: condición corporal baja con pastoreo más suplementación, condición corporal baja con pastoreo, condición corporal alta con pastoreo más suplementación y condición corporal alta con pastoreo. El pastoreo se realizó sobre un verdeo invernal (Secale cereale) con 73 % de digestibilidad in vitro y 18 % de Proteína bruta. El suplemento utilizado aportó 3Mcal EM/kg (alimento balanceado oveja en gestación) y fue suministrado a razón de 0,6 kg por animal. Se evaluaron mediante ANOVA los efectos de los tratamientos para los índices productivos peso al nacer y ganancia de peso en el primer mes de vida de los corderos mellizos. Descriptivamente se estudió la sobrevivencia de corderos mellizos y la evolución de la condición corporal de las ovejas que parieron y gestaron estos. Se complementó la información con coeficientes de correlación muestral para los pesos al nacer entre los corderos mellizos y las ganancias de peso vivo diario entre corderos hermanos. En años de oferta forrajera de calidad y cantidad adecuada, como la que existió al momento del ensayo, el aporte de suplemento energético cumpliría con la función de evitar la competencia de los fetos durante la gestación y lograr homogeneidad de peso al nacer entre los hermanos. La suplementación estratégica en ovejas que paren y gestan mellizos manifestó distinto comportamiento en función de la condición corporal inicial de la madre, sin embargo bajo las condiciones del estudio las diferencias de pesos al nacer de los corderos no justifican su utilización
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