1,082 research outputs found
Patterns of Lakeshore Usage Around Lake Bemidji
ABSTRACT - The eutrophication of lakes has been the subject of much discussion in scientific journals and the popular press .. Usually the e.utrophication process is accelerated by human activities. This study evaluates the extent of lakeshore development and recreational use of Lake Bemidji in north central Minnesota and examines the willingness of lakeshore residents to be assessed for corrective measures to halt deterioration of this valuable recreational lake. The shoreline of Lake Bemidji is highly developed, and the high density human habitation represents a potential source of nutrients from percolation through the sand and gravel soils which surround the lake. Residents around Lake Bemidji believe that growth of algae and aquatic vascular plants is not now severe and that it does not affect their use of the lake for recreational purposes. Although seventy-five percent of the residents favor regulation of lakeshore use and development, only 37 percent indicate willingness to be assessed for construction of a sewer line surrounding the lake
Double Excitation of He by Fast Ions
Autoionization of He atoms following double excitation by electrons, protons, CQ+ (Q=4-6), and FQ+ (Q=7-9) ions has been studied. The electron-emission yields from the doubly excited 2s2(1S), 2s2p(1P), and 2p2(1P) states were measured at the reduced projectile energy of 1.5 MeV/nucleon for observation angles between 10°and 60°. The results indicate excitation to the 2s2(1S) and 2p2(1D) states increases as approximately Q3, while excitation to the 2s2p(1P) state varies as approximately Q2, where Q is the charge of the projectile. These charge dependences are significantly less than the Q4 dependence expected in the independent-electron model, suggesting the interaction between the two target electrons is important in creating the doubly excited states
Projectile Energy Loss in Multiply Ionizing Ion-Atom Collisions
The projectile energy loss for 7.5--25-MeV C6+,5+ and F6+ ions was measured for single collisions with He, Ne, Ar, and Kr as a function of the recoil-ion charge state and the projectile scattering. This energy loss was measured for collisions in which the projectile captured an electron and for those involving just direct ionization. We investigated and found a large average energy transfer (100--250 eV/electron) to the continuum electrons. A strong increase of the scattering angle with recoil-ion charge state was observed for both capture and direct ionization. The results imply that, for smaller impact parameters, higher recoil-ion charge states are produced and that higher energy losses are obtained. We observed a weak target-Z dependence of the energy loss. The results are compared with n-body classical-trajectory Monte Carlo calculations by Olson, semiclassical-approximation calculations by Schuch et al. [Nucl. Instrum. Methods Phys. Res. Sect. B 42, 566 (1989)], and the energy-deposition model
Efficacy and Tolerability of Second-Generation Antipsychotics in Children and Adolescents With Schizophrenia
Early-onset schizophrenia-spectrum (EOSS) disorders (onset of psychotic symptoms before 18 years of age) represent a severe variant associated with significant chronic functional impairment and poor response to antipsychotic treatment. All drugs with proven antipsychotic effects block dopamine D2 receptors to some degree. The ongoing development of the dopamine and other neurotransmitter receptor systems during childhood and adolescence may affect clinical response and susceptibility to side effects in youth. A literature search was conducted of clinical trials of antipsychotics in children and adolescents with EOSS disorders between 1980 and 2007 from the Medline database, reference lists, and conference proceedings. Trials were limited to double-blind studies of duration of 4 or more weeks that included 15 or more patients. Ten clinical trials were identified. Antipsychotic medications were consistently found to reduce the severity of psychotic symptoms in children and adolescents when compared with placebo. The superiority of clozapine has been now demonstrated relative to haloperidol, standard-dose olanzapine, and “high-dose” olanzapine for EOSS disorders. However, limited comparative data are available regarding whether there are differences among the remaining second-generation antipsychotics (SGAs) in clinical effectiveness. The available data from short-term studies suggest that youth might be more sensitive than adults to developing antipsychotic-related adverse side effects (eg, extrapyramidal side effects, sedation, prolactin elevation, weight gain). In addition, preliminary data suggest that SGA use can lead to the development of diabetes in some youth, a disease which itself carries with it significant morbidity and mortality. Such a substantial risk points to the urgent need to develop therapeutic strategies to prevent and/or mitigate weight gain and diabetes early in the course of treatment in this population
Population of Highly Excited Intermediate Resonance States by Electron Transfer and Excitation
Coincidences between two sulfur K x rays were detected from collisions of hydrogenlike S ions with H2 gas in the projectile energy range between 150 and 225 MeV. These K x rays are emitted in the decay of doubly excited states formed in the collisions via transfer and excitation. The excitation function for two coincident Kβ transitions peaks at about 175 MeV, slightly above the expected KMM resonance energy for resonant transfer and excitation (RTE). This demonstrates the occurrence of ΔN≥2 transitions (i.e., KMM and higher resonances) in the RTE process. The cross sections for the population of the very highly excited states are higher than those predicted by theoretical calculations that use dielectronic recombination rates folded with the Compton profile for the bound electrons
Facing the music or burying our heads in the sand?: Adaptive emotion regulation in mid- and late-life
Psychological defense theories postulate that keeping threatening information out of awareness brings short-term reduction of anxiety at the cost of longer-term dysfunction. By contrast, Socioemotional Selectivity Theory suggests that preference for positively-valenced information is a manifestation of adaptive emotion regulation in later life. Using six decades of longitudinal data on 61 men, we examined links between emotion regulation indices informed by these distinct conceptualizations: defense patterns in earlier adulthood and selective memory for positively-valenced images in late life. Men who used more avoidant defenses in midlife recognized fewer emotionally-valenced and neutral images in a memory test 35-40 years later. Late-life satisfaction was positively linked with mid-life engaging defenses but negatively linked at the trend level with concurrent positivity bias
Surgical Training and Education in Promoting Professionalism: a comparative assessment of virtue-based leadership development in otolaryngology-head and neck surgery residents
Introduction: Surgical Training and Education in Promoting Professionalism (STEPP) was developed in 2011 to train tomorrow's leaders during residency. It is based on virtue ethics and takes an approach similar to West Point military academy. The purpose of this research was: (i) to compare the virtue profiles of our residents with that of the military cohort using a standardized virtue assessment tool; and (ii) to assess the value of virtue education on residents. Methods: As part of STEPP, otolaryngology residents participated in a virtue-based validated assessment tool called Virtue in Action (VIA) Inventory. This was completed at the initiation of STEPP in July 2011 as well as 1 year later in June 2012. Comparison of the VIA to a military cohort was performed. Leadership ‘Basic Training’ is a series of forums focused on virtues of initiative, integrity, responsibility, self-discipline, and accountability. A pre- and post-test was administered assessing resident perceptions of the value of this ‘Basic Training’. Results: Virtues are shared between otolaryngology residents (n=9) and military personnel (n=2,433) as there were no significant differences in strength scores between two military comparison groups and otolaryngology-head and neck surgery (OHNS) residents. There was a significant improvement (p<0.001) in the understanding of components of the leadership vision and a significant improvement in the understanding of key leadership concepts based on ‘Basic Training’. All residents responded in the post-test that the STEPP program was valuable, up from 56%. Conclusions: A virtue-based approach is valued by residents as a part of leadership training during residency
Search for extended gamma-ray emission from the Virgo galaxy cluster with Fermi-LAT
Galaxy clusters are one of the prime sites to search for dark matter (DM)
annihilation signals. Depending on the substructure of the DM halo of a galaxy
cluster and the cross sections for DM annihilation channels, these signals
might be detectable by the latest generation of -ray telescopes. Here
we use three years of Fermi Large Area Telescope (LAT) data, which are the most
suitable for searching for very extended emission in the vicinity of nearby
Virgo galaxy cluster. Our analysis reveals statistically significant extended
emission which can be well characterized by a uniformly emitting disk profile
with a radius of 3\deg that moreover is offset from the cluster center. We
demonstrate that the significance of this extended emission strongly depends on
the adopted interstellar emission model (IEM) and is most likely an artifact of
our incomplete description of the IEM in this region. We also search for and
find new point source candidates in the region. We then derive conservative
upper limits on the velocity-averaged DM pair annihilation cross section from
Virgo. We take into account the potential -ray flux enhancement due to
DM sub-halos and its complex morphology as a merging cluster. For DM
annihilating into , assuming a conservative sub-halo model
setup, we find limits that are between 1 and 1.5 orders of magnitude above the
expectation from the thermal cross section for
. In a more optimistic scenario, we
exclude
for for the same channel. Finally, we
derive upper limits on the -ray-flux produced by hadronic cosmic-ray
interactions in the inter cluster medium. We find that the volume-averaged
cosmic-ray-to-thermal pressure ratio is less than .Comment: 15 pages, 11 figures, 4 tables, accepted for publication in ApJ;
corresponding authors: T. Jogler, S. Zimmer & A. Pinzk
A preliminary quantitative mineral resource assessment of undiscovered porphyry copper resources in the Andes mountains of South America
Quantitative information on the probable locations and amounts of undiscovered porphyry copper resources of the world is important to international exploration managers, land-use and environmental planners, economists, and policy makers. The U.S. Geological Survey is organizing and facilitating a cooperative assessment, in collaboration with interested geological surveys and geological organizations, of the likely global distribution, quantity, and quality of selected undiscovered nonfuel mineral resources. This report on undiscovered porphyry copper deposits of the Andes Mountains was produced jointly with the geological surveys of Argentina, Chile, Colombia, and Peru, and is a summary of the more extensive report (>300 pages) that will be published soon. Reports on undiscovered copper resources of other regions of the world are being prepared and will be followed by assessments of the global undiscovered resources of platinum-group minerals and potash
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