114 research outputs found

    Cultural Implications of Late Quaternary Environmental Change in Northeastern Texas

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    Northeastern Texas is one of the most intensely studied archaeological regions of the state, principally for the two reasons that (1) archaeologically-rich Caddoan manifestations have long attracted interest and (2) many large land-modifying projects, such as reservoirs and strip mines, have occasioned environmental studies which include investigations of cultural resources. This greater amount of activity relative to other regions in the state has generally prevailed for more than a century (Guy 1990) and prospects are good that archaeologists will continue to intensely research the area in the foreseeable future. Unfortunately, however, they will be hard-pressed to keep pace with the destruction of archaeological sites. The region is growing in population and developing economically which inevitably results in land modifications destructive of archaeological evidence. Also, many sites are being willfully destroyed by commercial dealers in antiquities and by relic collectors. This contribution to historic preservation planning is concerned with gaining a better understanding of the past environmental factors that stimulated responses by past inhabitants of Northeastern Texas, and the natural environmental context of the archaeological record in Northeastern Texas. The area has some overall environmental similarities--such as being in a single physiographic section, and falling within a single climatic region--that might be misconstrued to imply a uniformity of conditions critical in pre-industrial human adaptations. In fact, the conditions important in human ecology vary significantly across space and have varied equally significantly over time

    Studies of Two-Phase Flow Dynamics and Heat Transfer at Reduced Gravity Conditions

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    The ability to predict gas-liquid flow patterns is crucial to the design and operation of two-phase flow systems in the microgravity environment. Flow pattern maps have been developed in this study which show the occurrence of flow patterns as a function of gas and liquid superficial velocities as well as tube diameter, liquid viscosity and surface tension. The results have demonstrated that the location of the bubble-slug transition is affected by the tube diameter for air-water systems and by surface tension, suggesting that turbulence-induced bubble fluctuations and coalescence mechanisms play a role in this transition. The location of the slug-annular transition on the flow pattern maps is largely unaffected by tube diameter, liquid viscosity or surface tension in the ranges tested. Void fraction-based transition criteria were developed which separate the flow patterns on the flow pattern maps with reasonable accuracy. Weber number transition criteria also show promise but further work is needed to improve these models. For annular gas-liquid flows of air-water and air- 50 percent glycerine under reduced gravity conditions, the pressure gradient agrees fairly well with a version of the Lockhart-Martinelli correlation but the measured film thickness deviates from published correlations at lower Reynolds numbers. Nusselt numbers, based on a film thickness obtained from standard normal-gravity correlations, follow the relation, Nu = A Re(sup n) Pr(exp l/3), but more experimental data in a reduced gravity environment are needed to increase the confidence in the estimated constants, A and n. In the slug flow regime, experimental pressure gradient does not correlate well with either the Lockhart-Martinelli or a homogeneous formulation, but does correlate nicely with a formulation based on a two-phase Reynolds number. Comparison with ground-based correlations implies that the heat transfer coefficients are lower at reduced gravity than at normal gravity under the same flow conditions. Nusselt numbers can be correlated in a fashion similar to Chu and Jones

    ABCB1 polymorphism predicts escitalopram dose needed for remission in major depression

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    The ATP-binding cassette family of transporter proteins, subfamily B (MDR/TAP), member 1 (ABCB1) (P-glycoprotein) transporter is a key component of the blood&ndash;brain barrier. Many antidepressants are subject to ABCB1 efflux. Functional polymorphisms of ABCB1 may influence central nervous system bioavailability of antidepressants subject to efflux. Single-nucleotide polymorphisms (SNPs) at rs1045642 (C3435T) of ABCB1 have been associated with efflux pump efficiency. This may explain part of the interindividual variation in antidepressant dose needed to remit. Individuals (N=113) with DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) major depressive disorder (MDD) were treated with escitalopram (ESC) or venlafaxine (VEN) over 8 weeks. The17-item Hamilton Depression Rating Scale was assessed serially, blind to genotype. SNP rs1045642 of ABCB1 along with two SNPs previously reported to be in linkage disequilibrium with it (rs2032582 and rs1128503) were genotyped. Demographic features, clinical features, P450 metabolizer status and 5-HTTLPR (serotonin-transporter-linked promoter region) genotype were controlled for. Carriers of rs1045642 TT needed on average 11&thinsp;mg of ESC to remit, whereas TC and CC carriers required 24 and 19&thinsp;mg, respectively (P=0.0001). This equates to a 2.0- (95% confidence interval=1.5&ndash;3.4; P&lt;0.001) fold greater ESC dose needed to remit for C carriers compared with TT carriers at rs1045642. Of VEN-treated subjects carrying TT genotype at rs1045642, 73.3% remitted compared with 12.5% for CC genotype (odds ratio=6.69; 95% confidence interval=1.72&ndash;25.9, P=0.006). These data suggest that antidepressant dose needed to remit can be predicted by an ABCB1 SNP. This has the potential clinical translation implications for dose selection and remission from MDD.<br /

    Cultural Resources Investigations Along Whiteoak Bayou, Harris County, Texas

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    In 1986, cultural resources investigations were carried out to prepare a synthesis of the archeology of the Whiteoak Bayou area in western Harris County, Texas, and to conduct subsurface testing at prehistoric sites that may be affected by the U.S. Army Corps of Engineers Upper Whiteoak Bayou Flood Damage Reduction Project. The tasks undertaken during these investigations are: (1) background research into the environment and archeology of the area; (2) historic/archival research and reconnaissance survey to summarize the historical development of Whiteoak Bayou and to identify any important sites in the project area; (3) intensive survey of Vogel Creek, a tributary to Whiteoak Bayou, to assess the potential for intact cultural remains; (4) National Register testing and assessment of nine aboriginal sites; (5) geoarcheological investigations to establish the geological context of the archeological remains, to identify the depositional environments represented, and to establish an alluvial sequence for the project area; and (6) analysis of a large collection of artifacts from 46 Whiteoak Bayou sites made prior to 1986 by members of the Houston Archeological Society, as well as the materials recovered during 1986. The nine archeological sites tesLed during this project are 41HR241, 4lHR259, 41HR273, 41HR278, 41HR279, 41HR283, 41HR290, 41HR298, and 41HR541. The testing showed that only three -- 41HR259, 41HR273, and 41HR541 -- have substantial, intact cultural deposits. Two of these -- 41HR273 and 41HR541 -- are judged to be eligible for listing on the National Register of Historic Places and for designation as State Archeological Landmarks. One site, 4lHR259, is currently listed on the National Register, although the remaining part of this site is judged to have a limited potential to yield additi0nal information. The other seven sites are judged to be ineligible for listing

    Control of rotorcraft retreating blade stall using air-jet vortex generators

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    A series of low-speed wind tunnel tests were carried out on an oscillating airfoil fitted with two rows of air-jet vortex generators (AJVGs). The airfoil used had an RAE 9645 section and the two spanwise arrays of AJVGs were located at x/c=0.12 and 0.62. The devices and their distribution were chosen to assess their ability to modify/control dynamic stall; the goal being to enhance the aerodynamic performance of helicopter rotors on the retreating blade side of the disc. The model was pitched about the quarter chord with a reduced frequency (k) of 0.1 in a sinusoidal motion defined by a=15o+10sin_ t. The measured data indicate that, for continuous blowing from the front row of AJVGs with a momentum blowing coefficient (C &#956;) greater than 0.008, modifications to the stalling process are encouraging. In particular, the pitching moment behavior exhibits delayed stall and there is a marked reduction in the normal force hysteresis

    Plasma neurofilament light chain protein is not increased in treatment-resistant schizophrenia and first-degree relatives

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    Objective: Schizophrenia, a complex psychiatric disorder, is often associated with cognitive, neurological and neuroimaging abnormalities. The processes underlying these abnormalities, and whether a subset of people with schizophrenia have a neuroprogressive or neurodegenerative component to schizophrenia, remain largely unknown. Examining fluid biomarkers of diverse types of neuronal damage could increase our understanding of these processes, as well as potentially provide clinically useful biomarkers, for example with assisting with differentiation from progressive neurodegenerative disorders such as Alzheimer and frontotemporal dementias. Methods: This study measured plasma neurofilament light chain protein (NfL) using ultrasensitive Simoa technology, to investigate the degree of neuronal injury in a well-characterised cohort of people with treatment-resistant schizophrenia on clozapine (n = 82), compared to first-degree relatives (an at-risk group, n = 37), people with schizophrenia not treated with clozapine (n = 13), and age- and sex-matched controls (n = 59). Results: We found no differences in NfL levels between treatment-resistant schizophrenia (mean NfL, M = 6.3 pg/mL, 95% confidence interval: [5.5, 7.2]), first-degree relatives (siblings, M = 6.7 pg/mL, 95% confidence interval: [5.2, 8.2]; parents, M after adjusting for age = 6.7 pg/mL, 95% confidence interval: [4.7, 8.8]), controls (M = 5.8 pg/mL, 95% confidence interval: [5.3, 6.3]) and not treated with clozapine (M = 4.9 pg/mL, 95% confidence interval: [4.0, 5.8]). Exploratory, hypothesis-generating analyses found weak correlations in treatment-resistant schizophrenia, between NfL and clozapine levels (Spearman’s r = 0.258, 95% confidence interval: [0.034, 0.457]), dyslipidaemia (r = 0.280, 95% confidence interval: [0.064, 0.470]) and a negative correlation with weight (r = −0.305, 95% confidence interval: [−0.504, −0.076]). Conclusion: Treatment-resistant schizophrenia does not appear to be associated with neuronal, particularly axonal degeneration. Further studies are warranted to investigate the utility of NfL to differentiate treatment-resistant schizophrenia from neurodegenerative disorders such as behavioural variant frontotemporal dementia, and to explore NfL in other stages of schizophrenia such as the prodome and first episode

    Formative Assessment of ARM-U: A Modular Intervention for Decreasing Risk Behaviors Among HIV-Positive and HIV-Negative Methamphetamine-Using MSM

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    BACKGROUND: Methamphetamine is a major contributor to HIV transmission among men who have sex with men (MSM). Recent studies show that up to one-third of methamphetamine-using MSM (MUMSM) inject the drug. We developed a behavioral intervention for MUMSM to decrease unprotected anal intercourse and increase awareness of parenteral HIV transmission risk. This 6-session (3 in-person, 3 by telephone) modular intervention was designed to be tailored to participants' HIV (+/-) and injection drug user ([IDU] yes/no) status. We present results of formative research used to evaluate the content and to assess feasibility and acceptability of this individual-level HIV risk-reduction intervention. SETTING: HIV research clinic in a high MSM and methamphetamine prevalence neighborhood. PROJECT: Avoiding Risks from Methamphetamine-Use (ARM-U) is a brief toolbox intervention that allows counselors to select modules that suit a client's individual risk profile and intervention needs employing motivational interviewing and cognitive behavioral theory. We evaluated the format and content of the intervention through focus groups and pre-testing of the entire intervention using volunteers from the target population stratified into four groups (HIV+/IDU, HIV-/IDU, HIV+/non-IDU, HIV-/non-IDU). Four individuals in each stratum were recruited to undergo the intervention and complete a satisfaction survey at the end of each in-person session. RESULTS: In total, 25 MUMSM attended one of five focus groups. Participants thought all proposed intervention topics were important and could aid in reducing sexual risk behaviors among MUMSM. However, the neurocognitive effects of methamphetamine were reported to be a barrier to practicing safer sex, condom use negotiation or HIV status disclosure. Fifteen (94%) of 16 participants completed all 6 sessions and the satisfaction survey. On average, participants felt the intervention was useful for MUMSM, made them contemplate and move toward behavior change, and would recommend the program to their peers. LESSONS LEARNED: Based on our formative research, we revised the ARM-U intervention to emphasize pre-planning to avoid combining methamphetamine use and sex or develop strategies to avoid sex risk following methamphetamine use. We also increased emphasis on referrals for care and other requested services. Future efficacy trials are needed to evaluate the intervention's ability to reduce HIV-associated risk behaviors

    Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa

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    There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.Social Science and Humanities Research Council of Canada; NORAM; American-Scandinavian Foundation; Fundacao para a Ciencia e Tecnologia [SFRH/BPD/73598/2010]; IGERT [DGE 0801634]; Hyde Family Foundations; Institute of Human Origins; National Science Foundation [BCS-9912465, BCS-0130713, BCS-0524087, BCS-1138073]; John Templeton Foundation to the Institute of Human Origins at Arizona State Universit
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