985 research outputs found
Genetic Studies of Deafness and of Retinitis Pigmentosa
In experimental animals where the generation time is short and matings can be controlled experimentally, it is a relatively simple task to determine whether a trait is genetic, how it is inherited, and where the causal gene pair is located. However, in human genetics, inferences must be drawn by pooling observations on many small families in which the trait of interest has occurred. The condition may be etiologically heterogeneous, resulting from environmental causes in some families and showing variable patterns of inheritance in others. Hereditary deafness and retinitis pigmentosa (RP) provide instructive examples of the problems involved in the genetic analysis of family data in man
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Geologic and Hydrogeologic Framework of Regional Aquifers in the Twin Mountains, Paluxy, and Woodbine Formations Near the SSC Site, North-Central Texas (Draft)
Water-utility districts and municipalities in North-Central Texas recently obtained as much as 100 percent of their water supply from deep regional aquifers in Cretaceous formations. Use of groundwater from the aquifers during the past century has resulted in water-level declines of as much as 800 ft (243.8 m) in Dallas and Tarrant Counties. Future continued water-level decline throughout North-Central Texas will depend on the amount of groundwater produced to help meet increased water-supply needs for municipal, industrial, and agricultural growth. It is probable that a significant part of the increased water demand will be met by groundwater.
The objectives of this study were to develop a hydrologic model of the complex interrelations among aquifer stratigraphy, hydrologic properties, and groundwater availability and, given expected patterns of future groundwater demand, to predict water-level changes in the regional aquifers that underlie North-Central Texas. A cross-sectional model of both aquifers and confining layers was used to evaluate model boundary conditions and the vertical hydrologic properties of the confining layers. Results and insights from the cross-sectional model were used in a three-dimensional simulation of groundwater flow in the deep aquifers. The layers of a regional confining system were not explicitly included in the three-dimensional model. Hydrogeologic properties were assigned based on aquifer test results and stratigraphic mapping of sandstone distribution in the aquifer units.Bureau of Economic Geolog
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Fault and Joint Measurements in Austin Chalk, SuperConducting Super Collider Site, Texas
Structure maps of 9.4 miles of nearly continuous tunnel excavations and more than 10 miles of other exposures and excavations in the Austin Chalk at the Superconducting Super Collider (SSC) site in Ellis County, Texas, record normal fault and joint populations in the subsurface within the northern segment of the Balcones Fault Zone that has unmatched resolution for such a long traverse. Small faults (less than 10 feet throw) occur in clusters or swarms that have as many as 24 faults. Fault swarms are as much as 2,000 feet wide, and spacing between swarms ranges from 800 to 2,000 feet, averaging about 1,000 feet. Predominantly northeast-trending joints are in swarms spaced 500 to more than 21,000 feet apart.Bureau of Economic Geolog
Top 10 Planning Events in North Carolina, 1946 – 2006
To celebrate the 60th anniversary of the establishment of the UNC-Chapel Hill Department of City and Regional Planning, this article outlines the top ten planning events, plans, and programs that have occurred in North Carolina in the past 60 years
40Ar/39Ar phlogopite geochronology of lamprophyre dykes in Cornwall, UK: new age constraints on Early Permian post-collisional magmatism in the Rhenohercynian Zone, SW England
Journal of the Geological Society (2015), http://jgs.lyellcollection.org/content/early/2015/06/03/jgs2014-151. Copyright © Geological Society of London 2015The spatial and temporal association of post-collisional granites and lamprophyre dykes is a common but enigmatic relationship in many orogenic belts, including the Variscan orogenic belt of SW England. The geology of SW England has long been interpreted to reflect orogenic processes associated with the closure of the Rheic Ocean and the formation of Pangaea. The SW England peninsula is composed largely of Early Devonian to Carboniferous volcano-sedimentary successions deposited in synrift and subsequent syncollisional basins that underwent deformation and low-grade regional metamorphism during the Variscan orogeny. Voluminous Early Permian granitic magmatism (Cornubian Batholith) is considered to be broadly coeval with the emplacement of lamprophyric dykes and lamprophyric and basaltic lava flows, largely on the basis of geochronological data from lamprophyric lavas in Devon. Although published geochronological data for Cornish lamprophyre dykes are consistent with this interpretation, these data are limited largely to imprecise K–Ar whole-rock and biotite analyses, hindering the understanding of the processes responsible for their genesis and their relationship to granitic magmatism and regional Variscan tectonics. 40Ar/39Ar geochronological data for four previously undated lamprophyre dykes from Cornwall, combined with published data, suggest that lamprophyre magmatism occurred between c. 293.6 and c. 285.4 Ma, supporting previous inferences that their emplacement was coeval with the Cornubian Batholith. These data provide insights into (1) the relative timing between the lamprophyres and basalts, the Cornubian batholith and post-collisional magmatism elsewhere in the European Variscides, and (2) the post-collisional processes responsible for the generation and emplacement of lamprophyres, basalts and granitoids.NSERC (Canada) Discovery grant
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Geologic and Hydrogeologic Framework of Regional Aquifers in the Twin Mountains, Paluxy, and Woodbine Formations Near the SSC Site, North-Central Texas
Water-utility districts and many municipalities in North-Central Texas
recently obtained as much as 100 percent of their water supply from deep
regional aquifers in Cretaceous formations. Use of groundwater from the
aquifers during the past century has resulted in water-level declines of as
much as 850 ft (259 m), especially in Dallas and Tarrant Counties. Future
water-level changes will depend on the amount of groundwater produced to
help meet growing water-supply needs for municipalities, industries, and
agriculture throughout North-Central Texas. It is probable that a significant
part of the increased water demand will be met by groundwater although at
less than historic rates.
The objective of this study was to develop a predictive tool for studying
the effect of future groundwater production from regional aquifers in North-Central
Texas. To do this, we reviewed the history of groundwater
development, hydrogeology of the regional aquifers, and constructed
numerical models of groundwater flow. A cross-sectional model of both
aquifers and confining layers was used to evaluate model boundary
conditions and the vertical hydrologic properties of the confining layers.
Results and insights from the cross-sectional model were used in a three-dimensional
simulation of groundwater flow in the deep aquifers. The layers
of the regional confining system were not explicitly included in the three-dimensional
model. Hydrogeologic properties were assigned on the basis of
aquifer test results and stratigraphic mapping of sandstone distribution in the
aquifer units.Bureau of Economic Geolog
Association Between Chronic Hepatitis C Virus Infection and Myocardial Infarction Among People Living With HIV in the United States.
Hepatitis C virus (HCV) infection is common among people living with human immunodeficiency virus (PLWH). Extrahepatic manifestations of HCV, including myocardial infarction (MI), are a topic of active research. MI is classified into types, predominantly atheroembolic type 1 MI (T1MI) and supply-demand mismatch type 2 MI (T2MI). We examined the association between HCV and MI among patients in the Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems, a US multicenter clinical cohort of PLWH. MIs were centrally adjudicated and categorized by type using the Third Universal Definition of Myocardial Infarction. We estimated the association between chronic HCV (RNA+) and time to MI while adjusting for demographic characteristics, cardiovascular risk factors, clinical characteristics, and history of injecting drug use. Among 23,407 PLWH aged ≥18 years, there were 336 T1MIs and 330 T2MIs during a median of 4.7 years of follow-up between 1998 and 2016. HCV was associated with a 46% greater risk of T2MI (adjusted hazard ratio (aHR) = 1.46, 95% confidence interval (CI): 1.09, 1.97) but not T1MI (aHR = 0.87, 95% CI: 0.58, 1.29). In an exploratory cause-specific analysis of T2MI, HCV was associated with a 2-fold greater risk of T2MI attributed to sepsis (aHR = 2.01, 95% CI: 1.25, 3.24). Extrahepatic manifestations of HCV in this high-risk population are an important area for continued research
Rational Herding in Microloan Markets
Microloan markets allow individual borrowers to raise funding from multiple individual lenders. We use a unique panel data set that tracks the funding dynamics of borrower listings on Prosper.com, the largest microloan market in the United States. We find evidence of rational herding among lenders. Well-funded borrower listings tend to attract more funding after we control for unobserved listing heterogeneity and payoff externalities. Moreover, instead of passively mimicking their peers (irrational herding), lenders engage in active observational learning (rational herding); they infer the creditworthiness of borrowers by observing peer lending decisions and use publicly observable borrower characteristics to moderate their inferences. Counterintuitively, obvious defects (e.g., poor credit grades) amplify a listing's herding momentum, as lenders infer superior creditworthiness to justify the herd. Similarly, favorable borrower characteristics (e.g., friend endorsements) weaken the herding effect, as lenders attribute herding to these observable merits. Follow-up analysis shows that rational herding beats irrational herding in predicting loan performance
Reliability and Validity of the HD-PRO-TriadTM, a Health-Related Quality of Life Measure Designed to Assess the Symptom Triad of Huntington\u27s Disease.
BACKGROUND: Huntington\u27s disease (HD), is a neurodegenerative disorder that is associated with cognitive, behavioral, and motor impairments that diminish health related quality of life (HRQOL). The HD-PRO-TRIADTM is a quality of life measure that assesses health concerns specific to individuals with HD. Preliminary psychometric characterization was limited to a convenience sample of HD participants who completed measures at home so clinician-ratings were unavailable.
OBJECTIVES: The current study evaluates the reliability and validity of the HD-PRO-TRIADTM in a well-characterized sample of individuals with HD.
METHODS: Four-hundred and eighty-two individuals with HD (n = 192 prodromal, n = 193 early, and n = 97 late) completed the HD-PRO-TRIADTM questionnaire. Clinician-rated assessments from the Unified Huntington Disease Rating Scales, the short Problem Behaviors Assessment, and three generic measures of HRQOL (WHODAS 2.0, RAND-12, and EQ-5D) were also examined.
RESULTS: Internal reliability for all domains and the total HD-PRO-TRIADTM was excellent (all Cronbach\u27s α \u3e0.93). Convergent and discriminant validity were supported by significant associations between the HD-PRO-TRIADTM domains, and other patient reported outcome measures as well as clinician-rated measures. Known groups validity was supported as the HD-PRO-TRIADTM differentiated between stages of the disease. Floor and ceiling effects were generally within acceptable limits. There were small effect sizes for 12-month change over time and moderate effect sizes for 24-month change over time.
CONCLUSIONS: Findings support excellent internal reliability, convergent and discriminant validity, known groups validity, and responsiveness to change over time. The current study supports the clinical efficacy of the HD-PRO-TRIADTM. Future research is needed to assess the test-retest reliability of this measure
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