Entangled Quantum Clocks for Measuring Proper-Time Difference

We report that entangled pairs of quantum clocks (non-degenerate quantum bits) can be used as a specialized detector for precisely measuring difference of proper-times that each constituent quantum clock experiences. We describe why the proposed scheme would be more precise in the measurement of proper-time difference than a scheme of two-separate-quantum-clocks. We consider possibilities that the proposed scheme can be used in precision test of the relativity theory.Comment: no correction, 4 pages, RevTe

Prominent bulk pinning effect in the MgB_2 superconductor

We report the magnetic-field dependence of the irreversible magnetization of the recently discovered binary superconductor MgB$_{2}$. For the temperature region of $T< 0.9T_c$, the contribution of the bulk pinning to the magnetization overwhelms that of the surface pinning. This was evident from the fact that the magnetization curves, $M(H)$, were well described by the critical-state model without considering the surface pinning effect. It was also found that the $M(H)$ curves at various temperatures scaled when the field and the magnetization were normalized by the characteristic scaling factors $H^\ast(T)$ and $M^\ast(T)$, respectively. This feature suggests that the pinning mechanism determining the hysteresis in $M(H)$ is unique below $T=T_c$.Comment: 4pages and 4 figures. Phys. Rev. B (accepted

Upstream Solutions: Does the Supplemental Security Income Program Reduce Disability in the Elderly?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72843/1/j.1468-0009.2007.00512.x.pd

Efficacy and Safety of Three Antiretroviral Regimens for Initial Treatment of HIV-1: A Randomized Clinical Trial in Diverse Multinational Settings

Background:Antiretroviral regimens with simplified dosing and better safety are needed to maximize the efficiency of antiretroviral delivery in resource-limited settings. We investigated the efficacy and safety of antiretroviral regimens with once-daily compared to twice-daily dosing in diverse areas of the world.Methods and Findings:1,571 HIV-1-infected persons (47% women) from nine countries in four continents were assigned with equal probability to open-label antiretroviral therapy with efavirenz plus lamivudine-zidovudine (EFV+3TC-ZDV), atazanavir plus didanosine-EC plus emtricitabine (ATV+DDI+FTC), or efavirenz plus emtricitabine-tenofovir-disoproxil fumarate (DF) (EFV+FTC-TDF). ATV+DDI+FTC and EFV+FTC-TDF were hypothesized to be non-inferior to EFV+3TC-ZDV if the upper one-sided 95% confidence bound for the hazard ratio (HR) was ≤1.35 when 30% of participants had treatment failure.An independent monitoring board recommended stopping study follow-up prior to accumulation of 472 treatment failures. Comparing EFV+FTC-TDF to EFV+3TC-ZDV, during a median 184 wk of follow-up there were 95 treatment failures (18%) among 526 participants versus 98 failures among 519 participants (19%; HR 0.95, 95% CI 0.72-1.27; p = 0.74). Safety endpoints occurred in 243 (46%) participants assigned to EFV+FTC-TDF versus 313 (60%) assigned to EFV+3TC-ZDV (HR 0.64, CI 0.54-0.76; p<0.001) and there was a significant interaction between sex and regimen safety (HR 0.50, CI 0.39-0.64 for women; HR 0.79, CI 0.62-1.00 for men; p = 0.01). Comparing ATV+DDI+FTC to EFV+3TC-ZDV, during a median follow-up of 81 wk there were 108 failures (21%) among 526 participants assigned to ATV+DDI+FTC and 76 (15%) among 519 participants assigned to EFV+3TC-ZDV (HR 1.51, CI 1.12-2.04; p = 0.007).Conclusion: EFV+FTC-TDF had similar high efficacy compared to EFV+3TC-ZDV in this trial population, recruited in diverse multinational settings. Superior safety, especially in HIV-1-infected women, and once-daily dosing of EFV+FTC-TDF are advantageous for use of this regimen for initial treatment of HIV-1 infection in resource-limited countries. ATV+DDI+FTC had inferior efficacy and is not recommended as an initial antiretroviral regimen.Trial Registration:http://www.ClinicalTrials.gov NCT00084136

Effectively Using Groundwater Geochemistry Data: A GIS Approach

The Savannah River Site (SRS) has accumulated a wealth of groundwater geochemistry data during the past two decades from a large network of monitoring wells. These data, archived in an Oracle database, have been accessible only in quarterly reports or a spreadsheet format. An ArcView extension has been developed to extract the data using a simple interface. The data are filtered, processed, and returned as an ArcView theme, permitting rapid analysis and evaluation of contaminated areas.Typically, these data must be analyzed by hydrostratigraphic unit to be useful. Unfortunately, a compendium of well screen-versus-aquifer relationships for groundwater monitoring wells at SRS has not been available, making the geochemical data difficult to use and analyze. Therefore, a 3-D hydrostratigraphic model has been developed in geographic information systems (GIS) and used in conjunction with well construction data to determine the location of well screen zones within the SRS vertical hydrostratigraphy. This information has been incorporated into the ArcView extension so that geochemical data can be analyzed and displayed in ArcView by hydrostratigraphic unit

Groundwater monitoring program evaluation For A/M Area, Savannah River Site

This investigation was undertaken with the primary purpose of assessing the groundwater monitoring program within the A/M Area to identify ways in which the monitoring program could be improved. The task was difficult due to the large number of wells located within the A/M Area and the huge database of analytical data. It was recognized early in this investigation that one of the key tasks was to develop a way to gain access to the groundwater databases so that recommendations could be made. To achieve this, geographic information systems (GIS) technology was used to extract pertinent groundwater quality information from the Geochemical Information Management System (GIMS) groundwater database and display the extracted information spatially. GIS technology was also used to determine the location of well screen and annular material zones within the A/M Area hydrostratigraphy and to identify wells that may breach confining units. Recommendations developed from this study address: (1) wells that may not be providing reliable data but continue to be routinely sampled (2) wells that may be inappropriately located but continue to be routinely sampled and (3) further work that should be undertaken, including well development, evaluation of wells that may be breaching confining units, and development of an automated link to GIMS using GIS so that GIMS data can easily be accessed and displayed geographically

Geographic Information Systems (GIS) Evaluation of Proposed Savannah River Site L-Lake Drawdown

L-Lake was created in 1985 to function as a once-through cooling water reservoir for L-Reactor at the Savannah River Site. The lake must be artificially maintained by pumping water from the Savannah River--at a significant annual cost. When L-Reactor was permanently shut down, studies were initiated to examine the ecological impact of a controlled L-Lake drawdown. An important part of these studies involved using GIS to develop a surface elevation model of the L-Lake floor based on side-scan sonar bathymetry data. The surface elevation model was validated by comparing computed lake volumes with engineering data acquired when the lake was filled. The surface model finally was used to determine the lake bottom slope and to estimate the spatial extent of the lake at various water levels

Air ingestion into the external loops of a Savannah River Site reactor during a postulated LOCA

The outlets to the external loops of a Savannah River Site reactor become exposed to air as the moderator tank drains during a postulated LOCA. When this happens the behavior of the pumps is adversely affected as is the flow through the core. The problems encountered in the simulation are those of the non-condensable gas being pulled through a free surface into the loops and the behavior of the pumps with the two-phase mixture. This paper presents the results of a LOCA simulation, the attempts made to model the air flow into the loops, and the modeling of the pump under two-phase conditions. 3 refs., 6 figs., 1 tab

Use of geographic information system to assess groundwater monitoring well integrity in a large well network at the Savannah River Site

Groundwater samples taken from wells that lack well construction integrity may produce unreliable data. One of the principal well construction integrity issues is whether the well filter-pack zone breaches an overlying or underlying confining unit. Examining well geophysical logs and related well data to identify wells with screen and filter-pack zones that may breach a confining unit is a time- intensive process. GIS, therefore, was utilized as an inexpensive screening tool to determine which wells at the Savannah River Site`s administrative and technical area potentially penetrate into or breach confining units. Three dimensional gridded surfaces representing the interfaces of aquifer and confining units were used in conjunction with well construction data obtained from a relational database in a GIS application written to locate well screen and filter-pack zone top and bottom elevations within the vertical hydrostratigraphy. The application then was used to identify wells with screen and filter-pack zones that potentially breach a confining unit. Use of these software tools enabled the efficient identification of 66 monitoring wells that may breach a confining unit within the Savannah River Site`s technical and administrative area. Geophysical logs from these wells will be examined to determine whether they should be removed from service

RELAP/FRAP-T6 analysis of seized and sheared shaft accidents. [PWR]

Argonne National Laboratory (ANL) performed audit calculations of a Reactor Coolant Pump (RCP) seized/sheared shaft transient for the Westinghouse Seabrook Plant using RELAP5/MOD 1.5 (Cycle 32) and FRAP-T6. The objective was to determine the effect of time of loss of offsite power and other single component failures on the peak clad temperature. The RCP shaft seizure event was modeled in RELAP5 by using the pump model shaft stop option. In modeling the sheared shaft failure, the faulted pump was replaced with a branch component having no flow losses. In general, the RELAP5-predicted system response for the seized shaft transient was very comparable to the results presented in the Seabrook FSAR, although the Reactor Coolant System (RCS) pressure response was somewhat different. The RELAP5 sheared-shaft analysis results were very similar to those for the seized shaft