Vulnerability, Risk, and the Transition to Adulthood

Examines whether poverty and single parenthood influence the likelihood of risk behavior and dropping out among youth and how these behaviors affect the trajectory of connectedness and employment patterns in adulthood. Considers policy implications

Introduction: absorbing the four methodological disruptions in democratization research?

This article introduces the special issue on methodological trends in democratization research by taking stock of the overall development of methods practices and situating the findings of the individual article contributions within the broader developments. As has the broader discipline, democratization research has experienced four methodological "disruptions" over the past 60 years: the behavioural revolution of statistical methodology; the introduction of formal theory; the sophistication of qualitative, set-theoretic and multi-method research; and the increasing use of experimental methods. Surveying the methods practices in the past quarter century, we find that quantitative and multi-method research have been growth areas in recent years, but that the bulk of research is still done in comparative or single case studies. Formal theory as well as set-theoretic methods have gained a foothold in the field, but it is still a small one. In sum, democratization research is, methodologically speaking, still rather traditional. Moreover, the individual contributions to this special issue show that much of the empirical literature underutilizes the best available advice about how to develop and test theory, including standards on causal inference, case-selection, and generalization. We conclude with a plea for more transparency, humility, and collaboration within and across methodological traditions

The phosphoinositide 3-kinase-dependent activation of Btk is required for optimal eicosanoid production and generation of reactive oxygen species in antigen-stimulated mast cells

Activated mast cells are a major source of the eicosanoids PGD(2) and leukotriene C(4) (LTC(4)), which contribute to allergic responses. These eicosanoids are produced following the ERK1/2-dependent activation of cytosolic phospholipase A(2), thus liberating arachidonic acid, which is subsequently metabolized by the actions of 5-lipoxygenase and cyclooxygenase to form LTC(4) and PGD(2), respectively. These pathways also generate reactive oxygen species (ROS), which have been proposed to contribute to FcepsilonRI-mediated signaling in mast cells. In this study, we demonstrate that, in addition to ERK1/2-dependent pathways, ERK1/2-independent pathways also regulate FcepsilonRI-mediated eicosanoid and ROS production in mast cells. A role for the Tec kinase Btk in the ERK1/2-independent regulatory pathway was revealed by the significantly attenuated FcepsilonRI-dependent PGD(2), LTC(4), and ROS production in bone marrow-derived mast cells of Btk(-/-) mice. The FcepsilonRI-dependent activation of Btk and eicosanoid and ROS generation in bone marrow-derived mast cells and human mast cells were similarly blocked by the PI3K inhibitors, Wortmannin and LY294002, indicating that Btk-regulated eicosanoid and ROS production occurs downstream of PI3K. In contrast to ERK1/2, the PI3K/Btk pathway does not regulate cytosolic phospholipase A(2) phosphorylation but rather appears to regulate the generation of ROS, LTC(4), and PGD(2) by contributing to the necessary Ca(2+) signal for the production of these molecules. These data demonstrate that strategies to decrease mast cell production of ROS and eicosanoids would have to target both ERK1/2- and PI3K/Btk-dependent pathways

Planning a Central Sewer System for Rural Areas

Rural areas may need planning assistance more than other areas. Population increases in non-metropolitan areas in the 1970s are more than offsetting the decreases of the previous decade. As population densities increase in these rural areas, community leaders must investigate alternatives to the individual septic tank and absorption field.Reviewed October 1993.Includes bibliographical reference

Anisotropy along a N-S profile of mica rich lithologies in the western Tauern Window (Eastern Alps, Austria)

Anatomy and internal structure of the Alpine orogens are difficult to decipher as structural information is usually limited to surface and seismic data. Seismic results very much depend on the elastic wave velocity model of the rocks. Simple velocity models depend strongly on the rock composition. Seismic properties are directionally dependent. Anisotropy can be subdivided into intrinsic (CPO of minerals and alignment in rock/texture) and extrinsic (compositional layering or fractures) anisotropy. In the investigated rock samples, phyllosilicates are by far most decisive for the elastic anisotropy due to their platy shape. We present here the first results of fabric analysis in a N-S profile of phyllosilicate-rich samples (mainly Innsbruck quartzphyllite and Bündner schist) from the Brenner Base Tunnel Project in order to obtain a refined anisotropy and velocity model. Phyllosilicate-rich sections were selected from borehole and tunnel samples, from which 1.5 – 3.5 mm wide columns were drilled out from layers of different composition and structure. The CPO of phyllosilicates and graphite was measured using high energy X-ray diffraction at German Electron Synchrotron (DESY) and European Synchrotron Radiation Facility (ESRF). Pole figure data were directly extracted using single peak evaluation and compared to the optical microstructure and compositional distributions using µXRF measurements. Texture strength is variable along the section with peak values at the transition from the Innsbruck quartzphyllite to the upper Bündner schist. The texture strength correlates positively with the content and distribution of phyllosilicates and graphite. By measuring the smallest representative volume element, we estimate the upper bound of expected intrinsic velocity anisotropies. The effect of (micro)structure-based upscaling on these anisotropies will be discussed

Vortex ring refraction at large Froude numbers

We have experimentally studied the impact of an initially planar axisymmetric vortex ring, incident at an oblique angle, upon a gravity-induced interface separating two fluids of differing densities. After impact, the vortex ring was found to exhibit a variety of subsequent trajectories, which we organize according to both the incidence angle, $\theta_i$, and the interface strength, defined as the ratio of the Atwood and Froude numbers, $A/F$. For grazing incidence angles ($\theta_i \gtrsim 70$ deg.) vortices either penetrate or reflect from the interface, depending on whether the interface is weak or strong. In some cases, reflected vortices execute damped oscillations before finally disintegrating. For smaller incidence angles ($\theta_i \lesssim 70$ deg.) vortices penetrate the interface. When there is a strong interface, these vortices are observed to curve back up toward the interface. When there is a weak interface, these vortices are observed to refract downward, away from the interface. The critical interface strength below which vortex ring refraction is observed is given by $\log_{10}{(A/F)}= -2.38 \pm 0.05$.Comment: 26 pages, 11 figures; Submitted to Physical Review