4,892 research outputs found

    The Necessary Right of Choice for Physician-Assisted Suicide

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    Research-based paper on the importance of the right for terminally ill patients facing a painful death to be able to choose how they end their lif

    Cathodoluminescence of oval defects in GaAs/AlxGa1–xAs epilayers using an optical fiber light collection system

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    A cathodoluminescence system using a novel optical fiber light collection system is employed to study oval defects in GaAs/Alx Ga1–x As epilayers grown by molecular beam epitaxy. Spatially and spectrally resolved data on the luminescence of oval defects are presented. Oval defects are found to contain an enhanced concentration of gallium, which is consistent with current theories regarding the origin of these defects

    Effect of doping on the optical gain and the spontaneous noise enhancement factor in quantum well amplifiers and lasers studied by simple analytical expressions

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    The maximum optical gain and the spontaneous noise enhancement factor in quantum well structures are expressed as extremely simple functions that are accurate over a wide range of carrier densities. These expressions are used to study the effect of doping on the optical gain and the noise enhancement factor in a 100 Γ… InGaAs/InP quantum well structure. n-type doping is most effective in reducing the transparency excitation level (laser threshold) and the noise enhancement factor (amplifier noise figure), whereas p-type doping enables increased gain at a given excitation level

    Skills, Qualities and Experiences Needed for Future Leaders in Food and Agribusiness Industries of Armenia

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    Armenian agribusiness industry, curriculum, skills, employer, education, Agribusiness, Industrial Organization, Teaching/Communication/Extension/Profession,

    Label-free, single molecule detection of cytokines using optical microcavities

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    Interleukin-2 (IL2) is a cytokine that regulates T-cell growth and is used in cancer therapies. By sensitizing a microcavity sensor surface with anti-IL2 and monitoring the resonant frequency, single molecules of IL2 can be detected

    Slip Along the San Andreas Fault Associated with the Earthquake

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    Some of the fault slip associated with the 1979 Imperial Valley earthquake occurred along other than the Imperial fault and the Brawley fault zone. More than 90 km to the north of the seismogenic fault, a 39-km-long section of the San Andreas fault developed a discontinuous set of surficial fractures soon after the earthquake. This set of fractures consisted of small left-stepping echelon cracks displaying extensional and dextral components of movement. Average dextral slip was about 4 mm, and slip reached 10 mm at one point along the fault. In one locality the cracks formed between Va and 4Vfe days after the main shock, although slippage at depth may have been nearly simultaneous with the earthquake. In general, this set of breaks duplicates the location, style, and slip magnitude of the set that was mapped in 1968 after the Borrego Mountain, Calif, earthquake. Such near-duplication indicates that this section of the San Andreas fault, in particular, is susceptible to small amounts of triggered slip. Although the reasons for such behavior are far from clear, similar behavior of the Imperial fault before 1979 suggests that this section of the San Andreas fault may generate a moderate earthquake within the next few decades

    Central California foreshocks of the great 1857 earthquake

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    Analysis of contemporary accounts indicates that several small to moderate central California earthquakes preceded the great 1857 earthquake by 1 to 9 hr. The earliest events apparently were felt only in the San Francisco area or the Sacramento and Sierran Foothills region. Two later and much more widely felt foreshocks were experienced within the region bounded by San Francisco, Visalia, Fort Tejon, and Santa Barbara. A comparison with felt areas and intensity distributions of modern events of known source and magnitude indicates that these later two shocks were 5 ≦M ≲ 6 and probably originated at some point within an area of radius β‰ˆ60 km that includes the southeastern 100 km of the historically creeping segment of the San Andreas fault. The northwestern terminus of the 1857 rupture is probably located along this segment. If the location of these foreshocks is indicative of the epicenter of the main event, then the several-hundred-kilometer main-event rupture propagated principally in a unilateral fashion toward the southeast. This implies that, like many great earthquakes, the 1857 rupture originated on a fault segment historically characterized by moderate activity and propagated into an historically quiet segment. There is a strong possibility that the foreshock activity represents a moderate Parkfield-Cholame sequence similar to those of 1901, 1922, 1934, and 1966. To the extent that such premonitory activity is characteristic of the failure of the 1857 segment of the fault, studies of the creeping segment of the fault may be relevant to the prediction of large earthquakes in central and southern California

    Pesticide effects on body temperature of torpid/hibernating rodents (Peromyscus leucopus and Spermophilus tridecemlineatus)

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    Environmental contaminants have been shown in the lab to alter thyroid hormone concentrations. Despite the role these hormones play in the physiological ecology of small mammals, no one has investigated the possible effects of thyroid-disrupting chemicals on mammalian thermal ecology and thermoregulatory ability. Because the energetic impact of such a disruption is likely to be most dramatic during times already energetically stressful, we investigated the effects of two common pesticides (atrazine and lindane) on the use of daily torpor in white-footed mice, and the use of hibernation in 13-lined ground squirrels. Fortunately, we found that these strategies for over-wintering success were not impaired
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