2,441 research outputs found

    Equal Employment Opportunity Commission v. Starbucks Corporation

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    Architectural Policy Design: How Policy Makers Try to Shape Policy Feedback Effects When Designing Policies

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    How do politicians use policies strategically for their own political benefit and to achieve long-term political goals, and how does such strategic behavior in- fluence the design of policies? Answering these questions is crucial for under- standing key dynamics, challenges, limitations and opportunities of public policy making, for explaining strategic choices policy makers make when they design new policies and political struggles they engage in with their oppo- nents

    Tectonic Implications of Small Earthquakes in the Central Transverse Ranges

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    Fault-plane solutions for 22 small (local magnitude (M_L ≤ 4.6) earthquakes in the central Transverse Ranges were determined using an azimuthally varying crustal model. The dominant type of faulting observed is reverse faulting on east-striking planes, which suggests a regional stress field characterized by north-south compression. Some strike-slip faulting also occurs. There is some indication that strike-slip earthquakes may be more common than reverse-slip earthquakes during episodes of crustal dilatation. The rate of north-south crustal shortening attributable to small-0earthquake deformation during 1974-76 is two orders of magnitude smaller than the north-south contraction of 0.3 parts per million per year measured at the surface. The scatter in earthquake hypocenters and the general inconsistency of focal mechanisms with geologically determined motions on nearby major faults indicate that the small earthquakes in this region are not associated with large-scale block movements along major fault systems. Rather, they appear to represent fracturing along random minor zones of weakness in response to the regional stress field or, alternatively, small-scale block movements that are below the resolution of this study. Earthquakes in the San Gabriel Mountains north of the Santa Susana-Sierra Madre-Cucamonga frontal fault system tend to concentrate near the eastern and western ends of the range, where good evidence for late Quaternary movement along the frontal faults has been found. Seismicity is markedly lower north of the central section of the frontal fault system, where evidence for late Quaternary movement is lacking

    The Retrospective Diagnosis of Attention-Deficit/Hyperactivity Disorder in Adolescents: Family Physicians\u27 Challenges

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    The primary purpose of the study was to identify current retrospective practices used by family physicians in the diagnosis of Attention-Deficit-Hyperactivity Disorder (ADHD) in adolescents and young adults. In other words, do physicians adhere to best practices and examine information from childhood in order to diagnose ADHD in adolescents and young adults? In addition, this study aimed to examine the information physicians request for ADHD diagnosis, types of treatments they recommend, the type of information they use to assess treatment outcomes, and professional attitudes regarding the nature of ADHD. Participants completed a questionnaire designed to answer the research questions. Participants included a random sample of members of the American Academy of Family Physicians (AAFP, N = 143) and a convenience sample (N = 84). Results indicated discrepancies between participating physicians\u27 current practices and best diagnostic practices, while these physicians generally reported treatment recommendations consistent with evidence-based practice. Reports of adherence to retrospective diagnostic practices and treatment outcome evaluation were limited, suggesting the need for training as well as collaboration with school professionals. Limitations of the current study and implications for future research are discussed

    Waveforms and spectra of preshocks and aftershocks of the 1979 Imperial Valley, California, Earthquake: evidence for fault hetergeneity

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    We have compared digitally-recorded waveforms of M_L 2.0–2.8 earthquakes that occurred in two small areas along the Imperial fault before and after it broke in the ML 6.6 Imperial Valley earthquake on October 15, 1979. Eight preshocks (1977–1979) from a 4½ by 1½ km area centered 4 km SE of the mainshock epicenter have strikingly similar waveforms over the entire record length (∼30 s), with an average peak cross correlation between seismograms of 0.74. The seismograms are well correlated at frequencies up to at least 4 Hz. This implies similar source mechanisms and hypocenters within ¼ of the 4-Hz wavelengths, i.e., <200–400 m. Five aftershocks from the same area show an average peak cross correlation between seismograms of only 0.23. Any associated changes in mechanism must be small because they are not reflected in the first motion data. Analysis of frequency content of these events using bandpass-filtering techniques showed no systematic temporal changes in spectral shape. Ten preshocks and 24 aftershocks from a 1½ by 2 km source area centered along the fault 16 km NW of the mainshock epicenter were also studied. First motion data suggest that all of the aftershocks and a swarm of six preshocks on December 7–9, 1978, were associated with the main fault but that four earlier preshocks were not. The six preshocks on December 7–9, 1978, were tightly clustered, as evidenced by the strong similarity of the waveforms (most peak cross correlations ≥0.6). During this swarm the 8- to 16-Hz spectral amplitude increased relative to the 1- to 2-Hz spectral amplitude over the whole record length by about a factor of 3, suggesting a systematic increase in stress drop. Groups of like events are also present among the aftershocks in this data set. The average peak correlation for pairs of aftershocks, 0.43, is almost the same as that for pairs of preshocks, 0.45, if all 10 preshocks are included. However, several sources appear to have been active simultaneously during the aftershock period so that no more than two to three consecutive aftershocks have maximum cross correlations ≥0.6. The highly localized sources characterized by waveform similarity may represent fault asperities or clusters of asperities. Our observations are consistent with a decrease in the number of these asperities as the weaker ones fail under increasing stress during the intervals between large earthquakes

    Contemporary tectonics of the Wasatch front region, Utah, from earthquake focal mechanisms

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    We have completed a comprehensive study of focal mechanisms of digitally recorded earthquakes (M, -_< 4.4) that occurred in the Wasatch front region in Utah during 1980 to 1986. Single-event solutions for 24 events were determined using recently revised crustal models and a computerized grid-search technique. Overall, the mechanisms show predominantly normal faulting on N-S-striking nodal planes of moderate to steep dip (>30°). Tension-axis azimuths average 96 ° _+ 12% Thus, in general, the mechanisms indicate E-W to ESE-WNW crustal extension and vertical crustal shortening. Oblique slip, when observed, is characterized by left-lateral motion on planes striking N to NE or right-lateral motion on planes striking N to NW. Most of the mechanisms with significant amounts of oblique-slip motion occur in the southern part of the study area, where compression- axis orientations range from near vertical to near horizontal. Thus, the mechanisms suggest a possible change in stress regime from north to south along the Wasatch front. Despite geologic evidence for low-angle faults in the study area, shallowly dipping nodal planes are relatively uncommon.This research was supported by the U.S. Geological Survey, Department of the Interior, under award numbers 14-08-0001-Gl163 and 14-08-0001- G1349. Partial support also came from a scholarship awarded by the Society of Exploration Geophysicists and sponsored by the Sohio Petroleum Company.Peer Reviewe
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