95 research outputs found

    Watson Brake, A Middle Archaic Mound Complex in Northeast Louisiana

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    Middle Archaic earthen mound complexes in the lower Mississippi valley are remote antecedents of the famous but much younger Poverty Point earthworks. Watson Brake is the largest and most complex of these early mound sites. Wry extensive coring and stratigraphic studies, aided by 25 radiocarbon dates and six huninescence dates, show that minor earthworks were begun here at ca. 3500 B.C. in association with an oval arrangement of burned rock middens at the edge of a stream terrace. The full extent of the first earthworks is not yet known. Substantial moundraising began ca. 3350 B.C. and continued in stages until some time after 3000 B.C. when the site was abandoned. All 11 mounds and their connecting ridges were occupied between building bursts. Soils,formed on some of these temporary surfaces, while lithics. fire-cracked rock. and,fired clay/loam objects became scattered throughout the mound fills. Faunal and floral remains from a basal midden indicate all-season occupation, supported by broad-spectrum foraging centered on nuts, fish, and deer All the overlying fills are so acidic that organics have not survived. The area enclosed by the mounds was kept clean of debris, suggesting its use as ritual space. The reasons why such elaborate activities first occurred here remain elusive. However some building bursts covary with very well-documented increases in El Nino/Southern Oscillation events. During such rapid increases in ENSO frequencies, rainfall becomes extremely erratic and unpredictable. It may be that early moundraising was a communal response to new stresses of droughts and flooding that created a suddenly more unpredictable food base

    Noninvasive, In Vivo Assessment of Mouse Retinal Structure Using Optical Coherence Tomography

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    BACKGROUND: Optical coherence tomography (OCT) is a novel method of retinal in vivo imaging. In this study, we assessed the potential of OCT to yield histology-analogue sections in mouse models of retinal degeneration. METHODOLOGY/PRINCIPAL FINDINGS: We achieved to adapt a commercial 3(rd) generation OCT system to obtain and quantify high-resolution morphological sections of the mouse retina which so far required in vitro histology. OCT and histology were compared in models with developmental defects, light damage, and inherited retinal degenerations. In conditional knockout mice deficient in retinal retinoblastoma protein Rb, the gradient of Cre expression from center to periphery, leading to a gradual reduction of retinal thickness, was clearly visible and well topographically quantifiable. In Nrl knockout mice, the layer involvement in the formation of rosette-like structures was similarly clear as in histology. OCT examination of focal light damage, well demarcated by the autofluorescence pattern, revealed a practically complete loss of photoreceptors with preservation of inner retinal layers, but also more subtle changes like edema formation. In Crb1 knockout mice (a model for Leber's congenital amaurosis), retinal vessels slipping through the outer nuclear layer towards the retinal pigment epithelium (RPE) due to the lack of adhesion in the subapical region of the photoreceptor inner segments could be well identified. CONCLUSIONS/SIGNIFICANCE: We found that with the OCT we were able to detect and analyze a wide range of mouse retinal pathology, and the results compared well to histological sections. In addition, the technique allows to follow individual animals over time, thereby reducing the numbers of study animals needed, and to assess dynamic processes like edema formation. The results clearly indicate that OCT has the potential to revolutionize the future design of respective short- and long-term studies, as well as the preclinical assessment of therapeutic strategies

    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

    Luminescence characteristics of quartz from Brazilian sediments and constraints for OSL dating

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    This study analyzes the optically stimulated luminescence (OSL) characteristics of quartz grains from fluvial, eolian and shallow marine sands of northeastern and southeastern Brazil, with especial focus on the applicability of the single-aliquot regenerative dose (SAR) dating protocol. All analyzed Brazilian sediments presented relatively high OSL sensitivity and good behavior regarding their luminescence characteristics relevant for radiation dose estimation. However, some samples from the Lençóis Maranhenses region in northeastern Brazil showed inadequate OSL sensitivity correction, hampering the implementation of the SAR protocol and their ability to behave as a natural dosimeter. While the shallow marine and eolian samples showed a narrow and reliable dose distribution, the fluvial sample had a wide dose distribution, suggesting incomplete bleaching and natural doses estimates dependent on age models

    Engaging terminally ill patients in end of life talk: How experienced palliative medicine doctors navigate the dilemma of promoting discussions about dying

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    Objective: To examine how palliative medicine doctors engage patients in end-of-life (hereon, EoL) talk. To examine whether the practice of “eliciting and responding to cues”, which has been widely advocated in the EoL care literature, promotes EoL talk. Design: Conversation analysis of video- and audio-recorded consultations. Participants: Unselected terminally ill patients and their companions in consultation with experienced palliative medicine doctors. Setting: Outpatient clinic, day therapy clinic, and inpatient unit of a single English hospice. Results: Doctors most commonly promoted EoL talk through open elaboration solicitations; these created opportunities for patients to introduce Ð then later further articulate Ð EoL considerations in such a way that doctors did not overtly ask about EoL matters. Importantly, the wording of elaboration solicitations avoided assuming that patients had EoL concerns. If a patient responded to open elaboration solicitations without introducing EoL considerations, doctors sometimes pursued EoL talk by switching to a less participatory and more presumptive type of solicitation, which suggested the patient might have EoL concerns. These more overt solicitations were used only later in consultations, which indicates that doctors give precedence to patients volunteering EoL considerations, and offer them opportunities to take the lead in initiating EoL talk. There is evidence that doctors treat elaboration of patients’ talk as a resource for engaging them in EoL conversations. However, there are limitations associated with labelling that talk as “cues” as is common in EoL communication contexts. We examine these limitations and propose “possible EoL considerations” as a descriptively more accurate term. Conclusions: Through communicating Ð via open elaboration solicitations Ð in ways that create opportunities for patients to volunteer EoL considerations, doctors navigate a core dilemma in promoting EoL talk: giving patients opportunities to choose whether to engage in conversations about EoL whilst being sensitive to their communication needs, preferences and state of readiness for such dialogue

    Role of community health workers in type 2 diabetes mellitus self-management: A scoping review

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    Background: Globally the number of people with Type 2 diabetes mellitus (T2DM) has risen significantly over the last few decades. Aligned to this is a growing use of community health workers (CHWs) to deliver T2DM self-management support with good clinical outcomes especially in High Income Countries (HIC). Evidence and lessons from these interventions can be useful for Low- and Middle-Income countries (LMICs) such as South Africa that are experiencing a marked increase in T2DM prevalence. Objectives: This study aimed to examine how CHW have been utilized to support T2DM self-management globally, their preparation for and supervision to perform their functions. Method: The review was guided by a stepwise approach outlined in the framework for scoping reviews developed by Arksey and O’Malley. Peer reviewed scientific and grey literature was searched using a string of keywords, selecting English full-text articles published between 2000 and 2015. Articles were selected using inclusion criteria, charted and content analyzed. Results: 1008 studies were identified of which 54 full text articles were selected. Most (53) of the selected studies were in HIC and targeted mostly minority populations in low resource settings. CHWs were mostly deployed to provide education, support, and advocacy. Structured curriculum based education was the most frequently reported service provided by CHWs to support T2DM self-management. Support services included informational, emotional, appraisal and instrumental support. Models of CHW care included facility linked nurse-led CHW coordination, facility-linked CHW led coordination and standalone CHW interventions without facility interaction. Conclusion: CHWs play several roles in T2DM self-management, including structured education, ongoing support and health system advocacy. Preparing and coordinating CHWs for these roles is crucial and needs further research and strengthening

    Space Requirements for Wheeled Mobility Devices in Public Transportation

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    Recent research on the anthropometry of wheeled mobility devices and their users (n = 369) indicates that the current dimensions for clear floor area prescribed in U. S. accessibility standards for transportation are inadequate for accommodating many users of wheeled mobility devices, especially those who use power chairs and scooters. The current report presents anthropometry data for determining the dimensions of clear floor area on the basis of occupied device length and width to achieve a specified level of physical accommodation. The implications of the findings and the need to revise guidelines for accessible public transportation systems are discussed. The transportation industry as well as mobility device manufacturers, vendors, and prescribers should understand the limitations of current standards and become involved in the dialogue about how to improve them
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