34,706 research outputs found

    Broadening the Mission: Research Activity among University Labor Education/Labor Studies Professionals

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    [Excerpt] This study examines research activity among university and college labor education/labor studies professionals. Using data gathered in a survey of faculty employed in the field, the paper presents information concerning the extent and focus of these research activities, the methodologies employed, the outlets for the research products that result, and the factors limiting such work. The findings of this study indicate that research, of both an applied and scholarly nature, is an increasingly significant part of the work of labor education/labor studies professionals. The study concludes with a discussion of the implications this trend has for the labor education/labor studies field, with special attention being given to the role research activity can play in meeting the needs of unions, union members, and union leaders

    The magnetic fields of forming solar-like stars

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    Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and collimation of spectacular outflows. The magnetic coupling with the disc is thought to influence the rotational evolution of the star, while magnetised stellar winds control the braking of more evolved stars and may influence the migration of planets. Magnetic reconnection events trigger energetic flares which irradiate circumstellar discs with high energy particles that influence the disc chemistry and set the initial conditions for planet formation. However, it is only in the past few years that the current generation of optical spectropolarimeters have allowed the magnetic fields of forming solar-like stars to be probed in unprecedented detail. In order to do justice to the recent extensive observational programs new theoretical models are being developed that incorporate magnetic fields with an observed degree of complexity. In this review we draw together disparate results from the classical electromagnetism, molecular physics/chemistry, and the geophysics literature, and demonstrate how they can be adapted to construct models of the large scale magnetospheres of stars and planets. We conclude by examining how the incorporation of multipolar magnetic fields into new theoretical models will drive future progress in the field through the elucidation of several observational conundrums.Comment: 55 pages, review article accepted for publication in Reports on Progress in Physics. Astro-ph version includes additional appendice

    Fracture mechanics approach to design analysis of notches, steps and internal cut-outs in planar components

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    A new approach to the assessment and optimization of geometric stress-concentrating features is proposed on the basis of the correspondence between sharp crack or corner stressfield intensity factors and conventional elastic stress concentration factors (SCFs) for radiused transitions. This approach complements the application of finite element analysis (FEA) and the use of standard SCF data from the literature. The method makes it possible to develop closed-form solutions for SCFs in cases where corresponding solutions for the sharp crack geometries exist. This is helpful in the context of design optimization. The analytical basis of the correspondence is shown, together with the limits on applicability where stress-free boundaries near the stress concentrating feature are present or adjacent features interact. Examples are given which compare parametric results derived from FEA with closed-form solutions based on the proposed method. New information is given on the stress state at a 90° corner or width step, where the magnitude of the stress field intensity is related to that of the corresponding crack geometry. This correspondence enables the user to extend further the application of crack-tip stress-field intensity information to square-cornered steps, external U-grooves, and internal cut-outs

    Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity

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    Aims: Stellar activity may complicate the analysis of high-precision radial-velocity spectroscopic data when looking for exoplanets signatures. We aim at quantifying the impact of stellar spots on stars with various spectral types and rotational velocities and comparing the simulations with data obtained with the HARPS spectrograph. Methods: We have developed detailed simulations of stellar spots and estimated their effects on a number of observables commonly used in the analysis of radial-velocity data when looking for extrasolar planets, such as radial-velocity curves, cross-correlation functions, bisector spans and photometric curves. The computed stellar spectra are then analyzed in the same way as when searching for exoplanets. Results: 1) A first grid of simulation results is built for F-K type stars, with different stellar and spot properties. 2) It is shown quantitatively that star spots with typical sizes of 1% can mimic both radial-velocity curves and the bisector behavior of short-period giant planets around G-K type stars with a vsini lower than the spectrograph resolution. For stars with intermediate vsini, smaller spots may produce similar features. In these cases, additional observables (e.g., photometry, spectroscopic diagnostics) are mandatory to confirm the presence of short-period planets. We show that, in some cases, photometric variations may not be enough to clearly rule out spots as explanations of the observed radial-velocity variations. This is particularly important when searching for super-Earth planets. 3) It is also stressed that quantitative values obtained for radial-velocity and bisector span amplitudes depend strongly on the detailed star properties, on the spectrograph used, on the set of lines used, and on the way they are measured.Comment: 12 pages, 16 figures, accepted for publication in A&

    Life long learning in rural areas: a report to the Countryside Agency

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    Lifelong Learning is a broad umbrella term which includes many different kinds of provision and different forms of learning. At its heart is formal learning, often classroom based, or involving paper and electronic media, undertaken within educational institutions such as colleges and universities. It may or may not lead to an award and it includes learning undertaken for vocational reasons as well as for general interest. It encompasses what are sometimes also known as adult education, continuing education, continuing professional development (cpd), vocational training and the acquisition of basic skills. It may also include work-based learning, and may overlap with post compulsory (post 16) education, i.e. with further education and higher education, but normally applies to all ‘adult learning’ i.e. by people over the age of 19, in particular those who are returning to study after completing their initial education. From the perspective of the individual learner, however, non-formal learning (organised, systematic study carried on outside the framework of the formal system) is also important. This forms a continuum with informal learning that occurs frequently in the process of daily living, sometimes coincidentally for example through information media or through interpretive provision (such as at museums or heritage sites ). This report focuses on those aspects of adult learning which are directly affected by government policies, and thus of prime concern for rural proofing

    High resolution spectroscopic study of red clump stars in the Galaxy: iron group elements

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    The main atmospheric parameters and abundances of the iron group elements (vanadium, chromium, iron, cobalt and nickel) are determined for 62 red giant "clump" stars revealed in the Galactic field by the Hipparcos orbiting observatory. The stars form a homogeneous sample with the mean value of temperature T=4750 +- 160K, of surface gravity log g = 2.41 +- 0.26 and the mean value of metallicity [Fe/H] = -0.04 +- 0.15 dex. A Gaussian fit to the [Fe/H] distribution produces the mean [Fe/H] = -0.01 dex and dispersion of [Fe/H] = 0.08 dex. The near-solar metallicity and small dispersion of [Fe/H] of clump stars of the Galaxy obtained in this work confirm the theoretical model of the Hipparcos clump by Girardi & Salaris (2001). This suggests that nearby clump stars are (in the mean) relatively young objects, reflecting mainly the near-solar metallicities developed in the local disk during the last few Gyrs of its history. We find iron group element to iron abundance ratios in clump giants to be close to solar.Comment: 9 pages, 7 figures, accepted for publication in MNRA

    Statistics of opinion domains of the majority-vote model on a square lattice

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    The existence of juxtaposed regions of distinct cultures in spite of the fact that people's beliefs have a tendency to become more similar to each other's as the individuals interact repeatedly is a puzzling phenomenon in the social sciences. Here we study an extreme version of the frequency-dependent bias model of social influence in which an individual adopts the opinion shared by the majority of the members of its extended neighborhood, which includes the individual itself. This is a variant of the majority-vote model in which the individual retains its opinion in case there is a tie among the neighbors' opinions. We assume that the individuals are fixed in the sites of a square lattice of linear size LL and that they interact with their nearest neighbors only. Within a mean-field framework, we derive the equations of motion for the density of individuals adopting a particular opinion in the single-site and pair approximations. Although the single-site approximation predicts a single opinion domain that takes over the entire lattice, the pair approximation yields a qualitatively correct picture with the coexistence of different opinion domains and a strong dependence on the initial conditions. Extensive Monte Carlo simulations indicate the existence of a rich distribution of opinion domains or clusters, the number of which grows with L2L^2 whereas the size of the largest cluster grows with lnL2\ln L^2. The analysis of the sizes of the opinion domains shows that they obey a power-law distribution for not too large sizes but that they are exponentially distributed in the limit of very large clusters. In addition, similarly to other well-known social influence model -- Axelrod's model -- we found that these opinion domains are unstable to the effect of a thermal-like noise
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