2,824 research outputs found
Transportation impact analysis for the shipment of low specific activity nitric acid. Revisison 1
This is in support of the Plutonium-Uranium Extraction (PUREX) Facility Low Specific Activity (LSA) Nitric Acid Shipment Environmental Assessment. It analyzes potential toxicological and radiological risks associated with transportation of PUREX Facility LSA Nitric Acid from the Hanford Site to Portsmouth VA, Baltimore MD, and Port Elizabeth NJ
The African American Male Achievement Dilemma Through the Eyes of the African American Male Superintendent
This research study explores the perspective of African American male superintendents on the African American male achievement dilemma. How do African American male superintendents theorize and respond to the underachievement of African American male students? Do their experiences give them greater insight, and how has this potential insight contributed to the implementation of initiatives that have improved the performance of this subgroup? Three major theoretical perspectives were explored during my review of the literature. Critical Race, Social Reproduction, and Oppositional Culture Theory encompassed the most consistent themes during my research, and helped to situate the study within the broader education context. The primary research method involved the interview of four African American male superintendents leading districts in the state of South Carolina. In addition to exploring their perspective of the African American achievement dilemma, the study sought to investigate the likelihood that there was a cultural connection that provided greater insight into strategies and practices that positively impacted African American achievement. The results of the study indicated that the primary explanation for the achievement dilemma experienced by African American male students was a shift in social and cultural dynamics. Specifically, the disintegration of the family unit and the diminishing influence the extended community and church has had on young men and families were identified as having the greatest impact. The most prevalent response to the achievement dilemma has been the establishment of comprehensive mentoring programs. Three of the four superintendents have established Bow Tie Club mentoring initiatives structured around the 5 Wellâs of Dr. Benjamin E. Mays. All activities support the goal of ensuring that the participants are Well Read, Well Spoken, Well Dressed, Well Traveled, and Well Balanced. Although the research identified systematic inequities and racism as having a significant impact on the African American maleâs ability to experience academic success, this study did not support that perspective
Potential evapotranspiration-related uncertainty in climate change impacts on river flow: An assessment for the Mekong River basin
SummarySix MIKE SHE models of the Mekong are developed, each employing potential evapotranspiration (PET) derived using alternative methods: BlaneyâCriddle (BC), Hamon (HM), HargreavesâSamani (HS), Linacre (LN), Penman (PN) and PriestleyâTaylor (PT). Baseline (1961â1990) PET varies, with PT followed by HS providing the lowest totals, LN and BC the highest. The largest mean annual PET is over 1.5times the smallest. Independent calibration of each model results in different optimised parameter sets that mitigate differences in baseline PET. Performance of each model is âexcellentâ (monthly NSE>0.85) or âvery goodâ (NSE: 0.65â0.85). Scenarios based on seven GCMs for a 2°C increase in global mean temperature are investigated. Inter-GCM variation in precipitation change is much larger (in percentage terms by 2.5â10times) than inter-GCM differences in PET change. Precipitation changes include catchment-wide increases or decreases as well as spatially variable directions of change, whereas PET increases for all scenarios. BC and HS produce the smallest changes, LN and HM the largest. PET method does impact scenario discharges. However, GCM-related uncertainty for change in mean discharge is on average 3.5times greater than PET method-related uncertainty. Scenarios with catchment-wide precipitation increases (decreases) induce increases (decreases) in mean discharge irrespective of PET method. Magnitude of change in discharge is conditioned by PET method; larger increases or smaller declines in discharge result from methods producing the smallest PET increases. Uncertainty in the direction of change in mean discharge due to PET method occurs for scenarios with spatially variable precipitation change, although this is limited to few gauging stations and differences are relatively small. For all scenarios, PET method-related uncertainty in direction of change in high and low flows occurs, but seasonal distribution of discharge is largely unaffected. As such, whilst PET method does influence projections of discharge, variation in the precipitation climate change signal between GCMs is a much larger source of uncertainty
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Radcalc for Windows 2.0 transportation packaging software to determine hydrogen generation and transportation classification
Radclac for Windows is a user friendly menu-driven Windows compatible software program with applications in the transportation of radioactive materials. It calculates the radiolytic generation of hydrogen gas in the matrix of low-level and high-level radioactive wastes. It also calculates pressure buildup due to hydrogen and the decay heat generated in a package at seal time. It computes the quantity of a radionuclide and its associated products for a given period of time. In addition, the code categorizes shipment quantities as reportable quantity (RQ), radioactive Type A or Type B, limited quality (LQ), low specific activity (LSA), highway road controlled quality (HRCQ), and fissile excepted using US Department of Transportation (DOT) definitions and methodologies
Risk-Based Capital in General Insurance
This paper looks at the problems of assessing, for solvency purposes, the capital requirements of a non-life insurer in the context of the United Kingdom. It considers how these capital requirements might vary according to the different risks to which an insurer is subject and how this Risk-Based Capital (RBC) might be measured in practice, using as a case study the RBC formula recently introduced in the United States of America. The paper also discusses the application of RBC concepts to the problem of internal capital allocation, to assist in measuring an insurer's rate of return to shareholders by business unit, as well as the more obvious regulatory application. The advantages and disadvantages of a formula-based approach to capital requirements for solvency purposes are discussed in comparison with possible alternative approaches to insurance supervisio
Associations between sole ulcer, white line disease and digital dermatitis and the milk yield of 1824 dairy cows on 30 dairy cow farms in England and Wales from February 2003âNovember 2004
The milk yields of 1824 cows were used to investigate the effect of lesion-specific causes of lameness, based on farmer treatment and diagnosis of lame cows, on milk yield. A three level hierarchical model of repeated test day yields within cows within herds was used to investigate the impact of lesion-specific causes of lameness (sole ulcer, white line disease, digital dermatitis and other causes) on milk yield before and after treatment compared with unaffected cows. Cattle which developed sole ulcer (SU) and white line disease (WLD) were higher yielding cattle before they were diagnosed. Their milk production fell to below that of the mean of unaffected cows before diagnosis and remained low after diagnosis. In cattle which developed digital dermatitis (DD) there was no significant difference in milk yield before treatment and a slightly raised milk yield immediately after treatment. The estimated milk loss attributable to SU and WLD was approximately 570kg and 370kg respectively. These results highlight that specific types of lameness vary by herds and within herds they are associated with higher yielding cattle. Consequently lesion-specific lameness reduction programmes targeting the cow and farm specific causes of lameness might be more effective than generic recommendations. They also highlight the importance of milk loss when estimating the economic impact of SU and WLD on the farms profitability
Chiral molecule adsorption on helical polymers
We present a lattice model for helicity induction on an optically inactive
polymer due to the adsorption of exogenous chiral amine molecules. The system
is mapped onto a one-dimensional Ising model characterized by an on-site
polymer helicity variable and an amine occupancy one. The equilibrium
properties are analyzed at the limit of strong coupling between helicity
induction and amine adsorption and that of non-interacting adsorbant molecules.
We discuss our results in view of recent experimental results
Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass
We report the first Lattice QCD calculation using the almost physical pion
mass mpi=149 MeV that agrees with experiment for four fundamental isovector
observables characterizing the gross structure of the nucleon: the Dirac and
Pauli radii, the magnetic moment, and the quark momentum fraction. The key to
this success is the combination of using a nearly physical pion mass and
excluding the contributions of excited states. An analogous calculation of the
nucleon axial charge governing beta decay has inconsistencies indicating a
source of bias at low pion masses not present for the other observables and
yields a result that disagrees with experiment.Comment: journal version; 15 pages, 6 figure
The issue of Dark Energy in String Theory
Recent astrophysical observations, pertaining to either high-redshift
supernovae or cosmic microwave background temperature fluctuations, as those
measured recently by the WMAP satellite, provide us with data of unprecedented
accuracy, pointing towards two (related) facts: (i) our Universe is accelerated
at present, and (ii) more than 70 % of its energy content consists of an
unknown substance, termed dark energy, which is believed responsible for its
current acceleration. Both of these facts are a challenge to String theory. In
this review I outline briefly the challenges, the problems and possible avenues
for research towards a resolution of the Dark Energy issue in string theory.Comment: Based on Invited lecture at the ``Third Aegean Summer School on: The
Invisible Universe: Dark matter and Dark energy'', Karfas, Chios Island
(Greece) September 26-October 1 200
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