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Research, Rummage, and Reconnoiter: Online Exploration at The Portal to Texas History
This presentation discusses what The Portal to Texas History is and the benefits that it provides to the community and to educators. It also illustrates how to use The Portal to Texas History, shows examples of the collections, and discusses future goals.
Date:
March 8, 2007
Creator:
Belden, Dreanna
Object Type:
Presentation
System:
The UNT Digital Library
Leaking Underground Storage Tanks: EPA Should Take Steps to Better Ensure the Effective Use of Public Funding for Cleanups
A letter report issued by the Government Accountability Office with an abstract that begins "Underground storage tanks that leak hazardous substances can contaminate nearby groundwater and soil. Under the Resource Conservation and Recovery Act (RCRA), tank owners and operators are primarily responsible for paying to clean up releases from their tanks. They can demonstrate their financial responsibility by using, among other options, publicly funded state financial assurance funds. Such funds function like insurance and are intended to ensure timely cleanup. These funds also pay to clean up releases from tanks without a viable owner, as does the federal Leaking Underground Storage Tank (LUST) Trust Fund. GAO was asked to report on (1) states' estimates of the public costs to clean up known releases, (2) states' primary sources of cleanups funding and their viability, and (3) federal sources to address these releases. GAO surveyed all states and discussed key issues with EPA and selected state officials."
Date:
February 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Defense Acquisitions: Analysis of Processes Used to Evaluate Active Protection Systems
A letter report issued by the Government Accountability Office with an abstract that begins "Active Protection Systems (APS) protect vehicles from attack by detecting and intercepting missiles or munitions. In 2005, the lead systems integrator for the Army's Future Combat Systems (FCS) program sought proposals for an APS developer and design and to deliver APS prototypes on vehicles by fiscal year 2009. Raytheon was chosen the APS developer. At the same time, the Department of Defense's Office of Force Transformation (OFT) evaluated near-term APS for potential use in Iraq. GAO was asked to review the Army's actions on APS/FCS: (1) the process for selecting the subcontractor to develop an APS for FCS and if potential conflicts of interest were avoided; (2) the timing of the trade study and if it followed a consistent methodology to evaluate alternatives, and the results; (3) the role the Army and Boeing played in selecting the developer; and (4) the process followed to provide a near-term APS solution for current forces."
Date:
June 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Military Personnel: Additional Actions Needed to Improve Oversight of Reserve Employment Issues
A letter report issued by the Government Accountability Office with an abstract that begins "Since September 11, 2001, the Department of Defense (DOD) has mobilized more than 500,000 reservists. As reservists demobilize, concerns exist about difficulties with their civilian employment. Public Law 109-163 required GAO to report on reservists' civilian employer data and employment matters. GAO assessed (1) the status of DOD's efforts to capture reservists' employer data; (2) DOD, Labor, Justice, and Office of Special Counsel processes to track and address reservists' Uniformed Services Employment and Reemployment Rights Act (USERRA) complaints; and (3) the four federal agencies' efforts to track reservists' USERRA complaints related to disabilities incurred while on active duty. GAO reviewed policies and procedures for reporting and tracking complaints; DOD's civilian employer database for reservists and reservists' USERRA complaints; and data reliability and quality checks."
Date:
February 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
VA Student Financial Aid: Management Actions Needed to Reduce Overlap in Approving Education and Training Programs and to Assess State Approving Agencies
A letter report issued by the Government Accountability Office with an abstract that begins "In fiscal year 2006, the Department of Veterans Affairs (VA) paid approximately $2.1 billion in education assistance benefits to more than 470,000 beneficiaries and about $19 million to state approving agencies (SAA) to assess whether schools and training programs offer education of sufficient quality for veterans to receive VA education assistance benefits when attending them. Qualified individuals--veterans, service persons, reservists, and certain spouses and dependents--receive benefits through a number of education assistance programs for the pursuit of various types of programs, such as a degree program, vocational program, apprenticeship, or on-the-job training. The Departments of Education (Education) and Labor (Labor) also assess education and training programs for various purposes, primarily for awarding student aid and providing apprenticeship assistance. In 2006, under Title IV of the Higher Education Act, Education provided nearly $77 billion in student aid in the form of both grants and loans. The Department of Education assesses and certifies postsecondary institutions for participation in Title IV programs through various oversight functions to ensure that these schools meet federal administrative and financial requirements and that they are accredited and licensed. Similarly, under the National Apprenticeship …
Date:
March 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Defense Transportation: DOD Has Taken Actions to Incorporate Lessons Learned in Transforming Its Freight Distribution System
Correspondence issued by the Government Accountability Office with an abstract that begins "The Department of Defense (DOD) transports second destination freight from over 600 locations to thousands of destinations throughout the continental United States each year at a cost of approximately $900 million. In 2001, DOD conducted a prototype program to better understand whether commercial best practices--specifically the use of a third-party logistics provider--could be applied to its freight transportation system and reduce costs. The prototype, which included a 1-year base agreement with two 1-year option periods, was conducted at selected Defense Logistics Agency (DLA) and military service shipping locations in the southeastern United States. At the conclusion of the first year, DLA exercised an option to extend the prototype at its shipping locations, whereas the military service shipping locations returned to DOD's previous freight shipping system due to dissatisfaction with the prototype's performance. On the basis of the prototype, DOD concluded that a third-party logistics provider could successfully integrate with DOD transportation processes if the program was designed and implemented correctly to capitalize on the benefits of using a third-party logistics provider while also addressing the performance problems that were experienced with the prototype. In 2004, the Under Secretary …
Date:
May 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Biofuels: DOE Lacks a Strategic Approach to Coordinate Increasing Production with Infrastructure Development and Vehicle Needs
A letter report issued by the Government Accountability Office with an abstract that begins "The U.S. transportation sector is almost entirely dependent on oil, a condition that poses significant economic and environmental risks. Biofuels, such as ethanol and biodiesel, have the potential to displace oil use in transportation fuel. GAO was asked to describe the status of and impediments to expanding biofuel production, distribution infrastructure, and compatible vehicles as well as federal policy options to overcome the impediments. GAO was also asked to assess the extent to which the Department of Energy (DOE) has developed a strategic approach to coordinate the expansion of biofuel production, infrastructure, and vehicles and has evaluated the effectiveness of biofuel tax credits. GAO interviewed representatives and reviewed studies and data from DOE, states, industry, and other sources."
Date:
June 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Military Personnel: DMDC Data on Officers' Commissioning Programs is Insufficiently Reliable and Needs to be Corrected
Correspondence issued by the Government Accountability Office with an abstract that begins "The Defense Manpower Data Center (DMDC) is a key Department of Defense (DOD) support organization that, among other things, generates reports for defense organizations such as the military services, the Office of the Secretary of Defense, and the Joint Staff. External organizations such as GAO and federally funded research and development centers also rely on DMDC for quantitative data and analyses pertaining to a wide variety of issues, including the numbers of DOD personnel in specified occupations or demographic groups, servicemembers' attitudes, and compensation. DMDC reports to DOD's Office of the Under Secretary of Defense for Personnel and Readiness. In describing its databases, DMDC states that it maintains the largest archive of personnel, manpower, training, and financial data in DOD. It also notes that the personnel data are broad in scope and extend back to the early 1970s covering all services, all components of the total force (active duty, guard, reserve, and civilian), and all phases of the personnel life cycle (accession, separation, and retirement). DMDC data serve as the basis for DOD's annual Population Representation in the Military Forces which, among other things, provides information on the …
Date:
March 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
NASA: Progress Made on Strategic Human Capital Management, but Future Program Challenges Remain
A letter report issued by the Government Accountability Office with an abstract that begins "The National Aeronautics and Space Administration (NASA) is engaged in efforts to replace the Space Shuttle with the next generation of human space flight systems and implement the President's space exploration policy. To do this, NASA must recruit, develop, and retain certain critical skills in its workforce, guided by its strategic human capital management plan. GAO was asked to examine the extent to which NASA (1) has aligned its human capital planning framework with its strategic mission and programmatic goals and (2) is recruiting, developing, and retaining critically skilled personnel, given future workforce needs. To address these objectives, GAO reviewed NASA's policies, planning, and implementation documents; reviewed budget documents and performance and accountability reports; and interviewed cognizant agency officials. To assess NASA's efforts to recruit, develop, and retain critically skilled personnel, we analyzed demographics data, and critical skills information; NASA's policy, procedures and guidance for recruiting and hiring; and implementation of information systems programs, and processes that support human capital management and planning. We are not making any recommendations in this report."
Date:
August 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Federal Aviation Administration: Cost Allocation Practices and Cost Recovery Proposal Compared with Selected International Practices
Correspondence issued by the Government Accountability Office with an abstract that begins "Anticipating the expiration of the Federal Aviation Administration's (FAA) current authorization at the end of fiscal year 2007, the administration submitted a proposal on February 14, 2007, for reauthorizing FAA and the excise taxes that fund most of its budget. This proposal would introduce cost-based charges for commercial users of air traffic control services, eliminate many current taxes, substantially raise fuel taxes for general aviation users to pay for their use of air traffic control services, and charge commercial and general aviation users a fuel tax to pay primarily for airport capital improvements. In January 2007, FAA released the results of a recently completed cost allocation study in support of the administration's proposal for transitioning to user fees. FAA and the administration used this study to determine the factors that drive the costs of providing air traffic control services, allocate these costs to various users of air traffic control services, and support the development of alternative methods to recover those costs. On March 21, 2007, we testified before the House Subcommittee on Aviation, providing our observations on selected changes to FAA's funding and budget structure contained in the …
Date:
June 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Higher Education: Issues Related to Law School Accreditation
A letter report issued by the Government Accountability Office with an abstract that begins "In order to participate in certain federal programs, such as federal student financial aid, postsecondary institutions must be accredited by an accrediting agency recognized by the Department of Education (Education). Accreditation ensures that schools provide basic levels of quality in their educational programs, and Education recognizes those agencies it concludes can reliably determine the quality of education provided by the schools and programs they accredit. Since 1952, Education has recognized the American Bar Association (ABA) as an accrediting agency for law schools. ABA accreditation is important to the 195 law schools it accredits because it allows their graduates the flexibility to take the Bar exam in any jurisdiction in the United States. The Department of Education requires that all recognized accrediting agencies periodically reapply for continued recognition. The Secretary of Education's accreditation advisory group, the National Advisory Committee on Institutional Quality and Integrity (NACIQI), considered the ABA's most recent application for continued recognition in December 2006. The ABA was originally scheduled for review in December 2005, but Education postponed it twice based on the large volume of public comments that had to be reviewed, as well …
Date:
March 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Military Personnel: Federal Agencies Have Taken Actions to Address Servicemembers' Employment Rights, but a Single Entity Needs to Maintain Visibility to Improve Focus on Overall Program Results
Testimony issued by the Government Accountability Office with an abstract that begins "Since September 11, 2001, the Department of Defense (DOD) has mobilized more than 500,000 National Guard and Reserve members. As reservists return to civilian life, concerns exist about difficulties with their civilian employment. The Uniformed Services Employment and Reemployment Rights Act (USERRA) of 1994 protects the employment rights of individuals, largely National Guard and Reserve members, as they transition back to their civilian employment. GAO has issued a number of reports on agency efforts to carry out their USERRA responsibilities. DOD, the Department of Labor (DOL), the Department of Justice (DOJ), and the Office of Special Counsel (OSC) have key responsibilities under the act. GAO was asked to discuss the overall process that the agencies use to implement USERRA. Specifically, this testimony addresses (1) organizational accountability in the implementation of USERRA and (2) actions that the agencies have taken to improve their processes to implement USERRA. For this testimony, GAO drew from its most recent reports on USERRA."
Date:
November 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Commonwealth of the Northern Mariana Islands: Serious Economic, Fiscal, and Accountability Challenges
Testimony issued by the Government Accountability Office with an abstract that begins "The U.S. insular area of the Commonwealth of the Northern Mariana Islands (CNMI) is a self-governing commonwealth of the United States that comprises 14 islands in the North Pacific. In a December 2006 report--U.S. Insular Areas: Economic, Fiscal, and Financial Accountability Challenges (GAO-07-119)--regarding four insular areas including CNMI, GAO identified and reported the following: (1) economic challenges, including the effect of changing tax and trade laws on their economies; (2) fiscal condition; and (3) financial accountability, including compliance with the Single Audit Act. The Chairman of the Senate Committee on Energy and Natural Resources, which requested the December 2006 report, asked GAO to present and discuss the results as they pertain to CNMI. Our summary and conclusions are based on our work performed for our December 2006 report on U.S. insular areas. For this testimony we also had available CNMI's fiscal year 2005 audited financial statements, which we have included in our review, along with some recent developments in fiscal year 2006."
Date:
February 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Federal Oversight of Food Safety: High-Risk Designation Can Bring Needed Attention to Fragmented System
Testimony issued by the Government Accountability Office with an abstract that begins "Each year, about 76 million people contract a foodborne illness in the United States; about 325,000 require hospitalization; and about 5,000 die. While the recent E. coli outbreaks highlighted the risks posed by accidental contamination, the attacks of September 11, 2001, heightened awareness that the food supply could also be vulnerable to deliberate contamination. This testimony focuses on the (1) role that GAO's high-risk series can play in raising the priority and visibility of the need to transform federal oversight of food safety, (2) fragmented nature of federal oversight of food safety, and (3) need to address federal oversight of food safety as a 21st century challenge. This work is based on previously issued reports."
Date:
February 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Coast Guard: Status of Efforts to Improve Deepwater Program Management and Address Operational Challenges
Testimony issued by the Government Accountability Office with an abstract that begins "The Coast Guard's Deepwater program is a 25-year, $24 billion plan to replace or modernize its fleet of vessels and aircraft. While there is widespread acknowledgment that many of the Coast Guard's aging assets need replacement or renovation, concerns exist about the acquisition approach the Coast Guard adopted in launching the Deepwater program. From the outset, GAO has expressed concern about the risks involved with the Coast Guard's acquisition strategy, and continues to review Deepwater program management. This statement discusses (1) the Coast Guard's acquisition approach for the Deepwater program; (2) Coast Guard efforts to manage the program, hold contractors accountable, and control costs through competition; (3) the status of the Coast Guard's efforts to acquire new or upgraded Deepwater assets; and (4) operational challenges the Coast Guard is facing because of performance and design problems with Deepwater patrol boats."
Date:
March 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
DOD and VA Health Care: Challenges Encountered by Injured Servicemembers during Their Recovery Process
Testimony issued by the Government Accountability Office with an abstract that begins "As of March 1, 2007, over 24,000 servicemembers have been wounded in action since the onset of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF), according to the Department of Defense (DOD). GAO work has shown that servicemembers injured in combat face an array of significant medical and financial challenges as they begin their recovery process in the health care systems of DOD and the Department of Veterans Affairs (VA). GAO was asked to discuss concerns regarding DOD and VA efforts to provide medical care and rehabilitative services for servicemembers who have been injured during OEF and OIF. This testimony addresses (1) the transition of care for seriously injured servicemembers who are transferred between DOD and VA medical facilities, (2) DOD's and VA's efforts to provide early intervention for rehabilitation for seriously injured servicemembers, (3) DOD's efforts to screen servicemembers at risk for post-traumatic stress disorder (PTSD) and whether VA can meet the demand for PTSD services, and (4) the impact of problems related to military pay on injured servicemembers and their families. This testimony is based on GAO work issued from 2004 through 2006 on the …
Date:
March 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Terrorist Watch List Screening: Recommendations to Promote a Comprehensive and Coordinated Approach to Terrorist-Related Screening
Testimony issued by the Government Accountability Office with an abstract that begins "The Federal Bureau of Investigation's (FBI) Terrorist Screening Center (TSC) maintains a consolidated watch list of known or appropriately suspected terrorists and sends records from the list to agencies to support terrorism-related screening. This testimony discusses (1) standards for including individuals on the list, (2) the outcomes of encounters with individuals on the list, (3) potential vulnerabilities in screening processes and efforts to address them, and (4) actions taken to promote effective terrorism-related screening. This statement is based on GAO's report (GAO-08-110). To accomplish the objectives, GAO reviewed documentation obtained from and interviewed officials at TSC, the FBI, the National Counterterrorism Center, the Department of Homeland Security, and other agencies that perform terrorism-related screening."
Date:
November 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Homeland Security: Observations on the Department of Homeland Security's Acquisition Organization and on the Coast Guard's Deepwater Program
Testimony issued by the Government Accountability Office with an abstract that begins "In January 2003, GAO designated the Department of Homeland Security's (DHS) implementation and transformation as high risk because of the size and complexity of the effort and the existing challenges faced by the components being merged into the department. The success of the effort to integrate numerous agencies and organizations into one cabinet-level department rests in large part on DHS's ability to effectively acquire the wide range of goods and services it needs to achieve its mission of protecting the nation from terrorism. DHS is undertaking a number of large, complex investments as the federal government increasingly relies on contractors for roles and missions previously performed by government employees. One of the department's largest investments--the Deepwater program, now estimated to cost $24 billion--is the Coast Guard's major effort to replace or modernize its aircraft and vessels. Rather than using a traditional acquisition approach, the Coast Guard is using a system integrator to design, construct, deploy, support, and integrate the Deepwater assets. In this testimony, the Comptroller General discussed (1) the overarching challenges DHS faces in establishing an effective acquisition organization, (2) GAO's prior work on Coast Guard and …
Date:
February 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Employee Misclassification: Improved Outreach Could Help Ensure Proper Worker Classification
Testimony issued by the Government Accountability Office with an abstract that begins "Some workers do not receive worker protections to which they are entitled because employers misclassify them as independent contractors when they should be classified as employees. Key worker protections include minimum hourly wage and overtime pay and access to unemployment insurance. The Department of Labor (DOL) enforces several labor laws to protect workers, including the Fair Labor Standards Act (FLSA). Misclassification can also have a negative impact on tax collection for Social Security, unemployment insurance, and other programs. This testimony draws upon a previous GAO report and focuses specifically on (1) the number and characteristics of independent contractors, (2) the workforce protections and benefits provided to employees that typically are not available to independent contractors, and (3) the actions that DOL takes to detect and address employee misclassification."
Date:
May 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Medicare Part D: Enrolling New Dual-Eligible Beneficiaries in Prescription Drug Plans
Testimony issued by the Government Accountability Office with an abstract that begins "Under the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA), dual-eligible beneficiaries--individuals with both Medicare and Medicaid coverage--have their drug costs covered under Medicare Part D rather than under state Medicaid programs. The MMA requires the Centers for Medicare & Medicaid Services (CMS) to enroll these beneficiaries in a Medicare prescription drug plan (PDP) if they do not select a plan on their own. CMS enrolled about 5.5 million dual-eligible beneficiaries in late 2005 and about 634,000 beneficiaries who became dually eligible during 2006. GAO was asked to testify on (1) CMS's process for enrolling new dual-eligible beneficiaries into PDPs and its effect on access to drugs and (2) how CMS set the effective coverage date for certain dual-eligible beneficiaries and its implementation of this policy. This testimony is based on a GAO report that is being released today, Medicare Part D: Challenges in Enrolling New Dual-Eligible Beneficiaries (GAO-07-272)."
Date:
May 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
Weather Forecasting: National Weather Service's Operations Prototype Needs More Rigorous Planning
A letter report issued by the Government Accountability Office with an abstract that begins "Using advanced systems and trained specialists located in 122 weather forecast offices throughout the country, the National Weather Service (NWS) provides storm and flood warnings and weather forecasts to protect life and property and to enhance the national economy. To improve the efficiency of its operations, in November 2006, NWS approved an effort to develop a prototype of an alternative way of operating. Under this prototype, weather forecasting offices would share selected responsibilities. GAO (1) determined the status of and plans for the prototype, (2) evaluated whether the prototype's justification was sufficient, (3) determined whether NWS's plans to evaluate the prototype are adequate, (4) evaluated whether NWS is sufficiently involving stakeholders in its prototype plans, and (5) determined how NWS plans to ensure that there will be no degradation of service during and after the prototype. To do so, GAO analyzed agency documentation and interviewed program officials and stakeholders."
Date:
June 8, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site
Hydrologic analyses are commonly based on a single conceptual-mathematical model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Considering conceptual model uncertainty is a critical process in hydrologic uncertainty assessment. This study assesses recharge and geologic model uncertainty for the Climax mine area of the Nevada Test Site, Nevada. Five alternative recharge models have been independently developed for Nevada and the Death Valley area of California. These models are (1) the Maxey-Eakin model, (2 and 3) a distributed parameter watershed model with and without a runon-runoff component, and (4 and 5) a chloride mass-balance model with two zero-recharge masks, one for alluvium and one for both alluvium and elevation. Similarly, five geological models have been developed based on different interpretations of available geologic information. One of them was developed by the U.S. Geological Survey for the Death Valley Regional Flow System (DVRFS) model; the other four were developed by Bechtel Nevada for the Yucca Flat Corrective Action Unit (CAU). The Climax mine area is in the northern part of the Yucca Flat CAU, which is within the DVRFS. A total of 25 conceptual models are thus formulated based on the five recharge …
Date:
November 8, 2007
Creator:
Ye, M.; Pohlmann, K.; Chapman, J. & Pohll, G.
Object Type:
Article
System:
The UNT Digital Library
Double Difference Earthquake Locations at the Salton Sea Geothermal Reservoir
The purpose of this paper is to report on processing of raw waveform data from 4547 events recorded at 12 stations between 2001 and 2005 by the Salton Sea Geothermal Field (SSGF) seismic network. We identified a central region of the network where vertically elongated distributions of hypocenters have previously been located from regional network analysis. We process the data from the local network by first autopicking first P and S arrivals; second, improving these with hand picks when necessary; then, using cross-correlation to provide very precise P and S relative arrival times. We used the HypoDD earthquake location algorithm to locate the events. We found that the originally elongated distributions of hypocenters became more tightly clustered and extend down the extent of the study volume at 10 Km. However, we found the shapes to depend on choices of location parameters. We speculate that these narrow elongated zones of seismicity may be due to stress release caused by fluid flow.
Date:
August 8, 2007
Creator:
Boyle, K L; Hutchings, L J; Bonner, B P; Foxall, W & Kasameyer, P W
Object Type:
Report
System:
The UNT Digital Library
Probing Late Neutrino Mass Properties With SupernovaNeutrinos
Models of late-time neutrino mass generation contain new interactions of the cosmic background neutrinos with supernova relic neutrinos (SRNs). Exchange of an on-shell light scalar may lead to significant modification of the differential SRN flux observed at earth. We consider an Abelian U(1) model for generating neutrino masses at low scales, and show that there are cases for which the changes induced in the flux allow one to distinguish the Majorana or Dirac nature of neutrinos, as well as the type of neutrino mass hierarchy (normal or inverted or quasi-degenerate). In some region of parameter space the determination of the absolute values of the neutrino masses is also conceivable. Measurements of the presence of these effects may be possible at the next-generation water Cerenkov detectors enriched with Gadolinium, or a 100 kton liquid argon detector.
Date:
August 8, 2007
Creator:
Baker, Joseph; Goldberg, Haim; Perez, Gilad & Sarcevic, Ina
Object Type:
Article
System:
The UNT Digital Library