91 research outputs found
The theological purpose of First Timothy as an ethic for the universal church
https://place.asburyseminary.edu/ecommonsatsdissertations/2035/thumbnail.jp
Preparing and Developing Community College International Leaders
Leadership training for future senior United States (US) community college leaders is an ongoing focus of US community college education. Leadership training is also a focus of US university international educators. Community college literature has assumed that full-time positions at community colleges devoted to overseeing and implementing internationalization do not exist and thus have not addressed succession opportunities. Based on a survey of 91 individuals who self-define their positions as ones in community college international leadership, this article examines what influences shaped the professional paths of these individuals and depicts criteria that can support future preparation for community college international education leadership from the viewpoint of those currently working in these positions. Pathway development patterns are seen in three forms: a) traditional preparation; b) non-traditional preparation; and c) job-embedded professional development
Proton Decay in Intersecting D-brane Models
We analyze proton decay via dimension six operators in certain GUT-like
models derived from Type IIA orientifolds with -branes. The amplitude is
parametrically enhanced by a factor of relative to the
coresponding result in four-dimensional GUT's. Nonetheless, even assuming a
plausible enhancement from the threshold corrections, we find little overall
enhancement of the proton decay rate from dimension six operators, so that the
predicted lifetime from this mechanism remains close to years.Comment: 21 pages, LaTeX; v2: references added; v3: minor clarifications,
version to appear in NP
New inflation in supersymmetric theories
A new inflationary universe scenario is considered based upon phase transitions in supersymmetric unified models where the Higgs potential is of the Witten-O'Raifeartaigh type.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25041/1/0000468.pd
Nonthermal Supermassive Dark Matter
We discuss several cosmological production mechanisms for nonthermal
supermassive dark matter and argue that dark matter may be elementary particles
of mass much greater than the weak scale. Searches for dark matter should not
be limited to weakly interacting particles with mass of the order of the weak
scale, but should extend into the supermassive range as well.Comment: 11 page LaTeX file. No major changes. Version accepted by PR
Main Bearing Replacement and Damage − A Field Data Study on 15 Gigawatts of Wind Energy Capacity
This study seeks to establish a comprehensive baseline of knowledge for the replacement and damage of main bearings in wind turbines. The purpose of this report is to provide a high-level summary of the data set, methodology, and results of this work. Full technical details and an extended analysis will be made available in a future publication. We collected data on main bearing replacements and reported damage from industrial partners based in Europe and the United States. In total, we obtained data for 167 wind power plants, with a combined capacity of 15.3 gigawatts (GW). Most of the data set was comprised of land-based, three-point mount, spherical roller bearings. Within this data set were 689 instances of main bearing replacement. Analysis was undertaken in two parts: first, a statistical analysis of the main bearing time-to-replacement data using survival analysis techniques; second, quantitative and qualitative analyses of the obtained damage information. Our results showed that 10% of a fixed main bearing population would be expected to have been replaced by 10.5 years. This is close to half of the 20-year design value. Fitted parametric distributions then indicated that by year 20, between 22% and 25% of main bearings are expected to have been replaced. Analysis of the damage reports revealed spalling to be the main type of damage listed. The additional presence of surface damage in the collected data indicates that at least part of the spalling cases are likely due to surface-initiated rolling contact fatigue. At this stage is not clear what proportion of spalling cases result from "wear induced", surface-initiated and subsurface-initiated rolling contact fatigue. While this work provides important insights into the current state of main bearing replacements and damage, many questions remain. An ongoing and expanding data collection and analysis effort focused on wind turbine main bearings is therefore recommended
High Energy Neutrinos From Superheavy Dark Matter Annihilation
Superheavy ( GeV) particles produced during inflation may be the
dark matter, independent of their interaction strength. Strongly interacting
superheavy particles will be captured by the sun, and their annihilation in the
center of the sun will produce a flux of energetic neutrinos that should be
detectable by neutrino telescopes. Depending on the particle mass, event rates
in a cubic-kilometer detector range from several per hour to several per year.
The signature of the process is a predominance of tau neutrinos, with a
relatively flat energy spectrum of events ranging from 50 GeV to many TeV, and
with the mean energy of detected tau neutrinos about 3 TeV.Comment: 24 pages, 7 figure
Evaluating the use of dominant microbial consumers (testate amoebae) as indicators of blanket peatland restoration
Peatlands represent globally-important ecosystems and carbon stores. However, large areas of peatland have been drained for agriculture, or peat has been harvested for use as fuel or in horticulture. Increasingly, these landscapes are being restored through ditch blocking and rewetting primarily to improve biodiversity and promote peat accumulation. To date we have little knowledge of how these interventions influence the microbial communities in peatlands. We compared the responses of dominant microbial consumers (testate amoebae) to drainage ditch restoration relative to unblocked ditches in a UK upland blanket peatland (Migneint, North Wales). Two techniques were used for restoration: (i) dammed ditches with re-profiling; and (ii) dammed ditches with pools of open water behind each dam. Testate communities in the inter-ditch areas changed markedly over time and between treatments illustrating the potential of this group of organisms as indicators of blanket peatland restoration status. However, the responses of testate amoebae to peat rewetting associated with restoration were partially obscured by inter-annual variability in weather conditions through the course of the experiment. Although there was considerable variability in the response of testate amoebae communities to peatland drain blocking, there were clearly more pronounced changes in samples from the dammed and reprofiled treatments including an increase in diversity, and the appearance of unambiguous wet-indicator species in relatively high abundances (including Amphitrema stenostoma, Archerella flavum, Arcella discoides type, Difflugia bacillifera and Difflugia bacillarium). This reflects a shift towards overall wetter conditions across the site and the creation of new habitats. However, water-table was not a significant control on testate amoebae in this case, suggesting a poor relationship between water table and surface moisture in this sloping blanket peatland. Our findings highlight the potential of testate amoebae as bioindicators of peatland restoration success; however, there is a need for caution as mechanisms driving change in the microbial communities may be more complex than first assumed. Several factors need to be taken into account when implementing biomonitoring studies in peatlands including: (i) the natural variability of the peatland ecosystem under changing weather conditions; (ii) any disturbance connected with the restoration procedures; and (iii) the timescales over which the ecosystem responds to the management intervention. Our results also suggest an indicator species approach based on population dynamics may be more appropriate for biomonitoring peatland restoration than examining changes at the community level
Exotic massive hadrons and ultra-high energy cosmic rays
We investigate the proposal that primary cosmic rays of energy above the
Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting
particles (uhecrons). We study the properties of air showers produced by
uhecrons and find that masses in excess of about 50 GeV are inconsistent with
the highest energy event observed. We also estimate that with sufficient
statistics a uhecron of mass as low as 10 GeV may be distinguished from a
proton.Comment: 27 pages, 15 figures - fig5b was replace
Testing peatland water-table depth transfer functions using high-resolution hydrological monitoring data
Transfer functions are now commonly used to reconstruct past environmental variability from palaeoecological data. However, such approaches need to be critically appraised. Testate amoeba-based transfer functions are an established method for the quantitative reconstruction of past water-table variations in peatlands, and have been applied to research questions in palaeoclimatology, peatland ecohydrology and archaeology. We analysed automatically-logged peatland water-table data from dipwells located in England, Wales and Finland and a suite of three year, one year and summer water-table statistics were calculated from each location. Surface moss samples were extracted from beside each dipwell and the testate amoebae community composition was determined. Two published transfer functions were applied to the testate-amoeba data for prediction of water-table depth (England and Europe). Our results show that estimated water-table depths based on the testate amoeba community reflect directional changes, but that they are poor representations of the real mean or median water-table magnitudes for the study sites. We suggest that although testate amoeba-based reconstructions can be used to identify past shifts in peat hydrology, they cannot currently be used to establish precise hydrological baselines such as those needed to inform management and restoration of peatlands. One approach to avoid confusion with contemporary water-table determinations is to use residuals or standardised values for peatland water-table reconstructions. We contend that our test of transfer functions against independent instrumental data sets may be more powerful than relying on statistical testing alone
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