7,997 research outputs found
The average magnetic field draping and consistent plasma properties of the Venus magnetotail
A new technique has been developed to determine the average structure of the Venus magnetotail (in the range from −8 Rv to −12 Rv) from the Pioneer Venus magnetometer observations. The spacecraft position with respect to the cross-tail current sheet is determined from an observed relationship between the field-draping angle and the magnitude of the field referenced to its value in the nearby magnetosheath. This allows us statistically to remove the effects of tail flapping and variability of draping for the first time and thus to map the average field configuration in the Venus tail. From this average configuration we calculate the cross-tail current density distribution and J × B forces. Continuity of the tangential electric field is utilized to determine the average variations of the X-directed velocity which is shown to vary from −250 km/s at −8 Rv to −470 km/s at −12 Rv. From the calculated J × B forces, plasma velocity, and MHD momentum equation the approximate plasma acceleration, density, and temperature in the Venus tail are determined. The derived ion density is approximately ∼0.07 p+/cm³ (0.005 O+/cm³) in the lobes and ∼0.9 p+/cm³ (0.06 O+/cm³) in the current sheet, while the derived approximate average plasma temperature for the tail is ∼6×106 K for a hydrogen plasma or ∼9×107 K for an oxygen plasma
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Self-immolative linkers in polymeric delivery systems
There has been significant interest in the methodologies of controlled release for a diverse range of applications spanning drug delivery, biological and chemical sensors, and diagnostics. The advancement in novel substrate-polymer coupling moieties has led to the discovery of self-immolative linkers. This new class of linker has gained popularity in recent years in polymeric release technology as a result of stable bond formation between protecting and leaving groups, which becomes labile upon activation, leading to the rapid disassembly of the parent polymer. This ability has prompted numerous studies into the design and development of self-immolative linkers and the kinetics surrounding their disassembly. This review details the main concepts that underpin self-immolative linker technologies that feature in polymeric or dendritic conjugate systems and outlines the chemistries of amplified self-immolative elimination
Candidates for asteroid dust trails
The contribution of different sources to the circumsolar dust cloud (known as the zodiacal cloud) can be deduced from diagnostic observations. We used the Spitzer Space Telescope to observe the diffuse thermal emission of the zodiacal cloud near the ecliptic. Several structures were identified in these observations, including previously known asteroid dust bands, which are thought to have been produced by recent asteroid collisions, and cometary trails. Interestingly, two of the detected dust trails, denoted t1 and t2 here, cannot be linked to any known comet. Trails t1 and t2 represent a much larger integrated brightness than all known cometary trails combined and may therefore be major contributors to the circumsolar dust cloud. We used our Spitzer observations to determine the orbits of these trails and were able to link them to two ("orphan" or type II) trails that were discovered by the Infrared Astronomical Satellite (IRAS) in 1983. The orbits of trails t1 and t2 that we determined by combining the Spitzer and IRAS data have semimajor axes, eccentricities, and inclinations like those of the main-belt asteroids. We therefore propose that trails t1 and t2 were produced by very recent (<~100 kyr old) collisional breakups of small, <~10 km diameter main-belt asteroids
Raising Cash Under Duress And The Role Of Cash Value Life Insurance: An Educational Example
Consumers face hard choices when they need cash quickly. Hard choices can lead to emotional or economically unsound decisions. Traditional classroom discussions of raising funds to pay for expenses usually focus on generating income, borrowing, or the sale of real and financial assets, if hardship is discussed at all. However, many families have additional “non-traditional” sources of cash. This article examines the use of life insurance surrenders and policy loans as a source of funds for both routine funding needs as well as a source of emergency financing. The article concludes with a review of the economic considerations of life insurance for Insurance and Financial Planning educators and students
The Qualitative Interview in Psychology and the Study of Social Change: Sexual Identity Development, Minority Stress, and Health in the Generations Study.
Interviewing is considered a key form of qualitative inquiry in psychology that yields rich data on lived experience and meaning making of life events. Interviews that contain multiple components informed by specific epistemologies have the potential to provide particularly nuanced perspectives on psychological experience. We offer a methodological model for a multi-component interview that draws upon both pragmatic and constructivist epistemologies to examine generational differences in the experience of identity development, stress, and health among contemporary sexual minorities in the United States. Grounded in theories of life course, narrative, and intersectionality, we designed and implemented a multi-component protocol that was administered among a diverse sample of three generations of sexual minority individuals. For each component, we describe the purpose and utility, underlying epistemology, foundational psychological approach, and procedure, and we provide illustrative data from interviewees. We discuss procedures undertaken to ensure methodological integrity in process of data collection, illustrating the implementation of recent guidelines for qualitative inquiry in psychology. We highlight the utility of this qualitative multi-component interview to examine the way in which sexual minorities of distinct generations have made meaning of significant social change over the past half-century
Factors Influencing Willingness-to-Pay for the Energy Star Label
In the United States, nearly 17 percent of greenhouse gas emissions come from residential energy use. Increases in energy efficiency for the residential sector can generate significant energy savings and emissions reductions. Consumer labels, such as USEPA’s Energy Star, promote conservation by providing consumers with information on energy usage for household appliances. This study examines how the Energy Star label affects consumer preferences for refrigerators. An online survey of a national sample of adults suggest that consumers are, on average, willing to pay an extra 349.30 for a refrigerator that has been awarded the Energy Star label. Furthermore, the results provide evidence that willingness to pay was motivated by both private (energy cost savings) and public (environmental) benefits.Energy Star, willingness-to-pay, eco-label, Consumer/Household Economics, Demand and Price Analysis, Environmental Economics and Policy,
Dramatic Raman Gain Suppression in the Vicinity of the Zero Dispersion Point in Gas-Filled Hollow-Core Photonic Crystal Fiber
In 1964 Bloembergen and Shen predicted that Raman gain could be suppressed if
the rates of phonon creation and annihilation (by inelastic scattering) exactly
balance. This is only possible if the momentum required for each process is
identical, i.e., phonon coherence waves created by pump-to-Stokes scattering
are identical to those annihilated in pump-to-anti-Stokes scattering. In bulk
gas cells, this can only be achieved over limited interaction lengths at an
oblique angle to the pump axis. Here we report a simple system that provides
dramatic Raman gain suppression over long collinear path-lengths in hydrogen.
It consists of a gas-filled hollow-core photonic crystal fiber whose zero
dispersion point is pressure-adjusted to lie close to the pump laser
wavelength. At a certain precise pressure, generation of Stokes light in the
fundamental mode is completely suppressed, allowing other much weaker nonlinear
processes to be explored.Comment: 4 pages, 5 figure
Asthma in Vermont Dairy Farmers
Introduction. Although 5.4% of the Vermont population participates in agriculture as an occupation, little data exists on the prevalence of asthma in Vermont dairy farmers, due to inadequate sample sizes. Previous studies have shown dairy farmers are at risk of respiratory illness due to unique exposures intrinsic to their occupation. We conducted a study to assess the prevalence of asthma in dairy farmers in Vermont, to understand rates among this population and potential occupational risks.Methods. We distributed a paper survey modeled after previously-validated surveys, such as the BRFSS, to farmers at Vermont Farmer Bureau meetings, farmers markets, and individual farmers through Cabot Creamery. Out of 309 distributed surveys, we received 176 completed surveys for a response rate of 57%.Results. Self-reported asthma rate in dairy farmers was 21% (22% in dairy only farmers), with 90% of these cases reported as confirmed by a doctor. Of non-dairy farmers, 11% self-reported experiencing asthma. Farming activities associated with exacerbation of asthma symptoms were milking, prepping or cleaning bedding, and haying. 31% of dairy-only farmers reported symptom exacerbations due to these occupational triggers.Conclusions. The prevalence of asthma in Vermont dairy farmers is one of the highest reported rates in any Vermont occupation. Our data suggest that certain occupational exposures may increase risk of asthma and warrant further study; certain farming practices were associated with exacerbation of respiratory symptoms in farmers diagnosed with asthma. These findings and further research can assist in development of health care and preventive health measures for farmers.https://scholarworks.uvm.edu/comphp_gallery/1238/thumbnail.jp
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