3,450 research outputs found

    A re-assessment of the distribution of Virginia\u27s warbler in the Black Hills of South Dakota

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    Virginia’s Warbler (Oreothlypis virginiae) reaches the northeastern limit of its breeding range in the southern Black Hills of South Dakota, where it is considered a species of conservation concern. This population occurs in pine–juniper–shrub habitat in several canyons in extreme western Custer County. Additional such habitat occurs in the southern Black Hills south and east of the documented breeding populations, but these areas have received few systematic surveys, and whether Virginia’s Warbler occupies them was uncertain. Therefore, to define the species’ distribution in the South Dakota Black Hills more precisely, we surveyed with the aid of broadcast song and reviewed other reports. Virginia’s Warblers occurred in appropriate habitats all along the southwestern front (approximately 30 km total) of the Black Hills in Custer County but did not occur in similar habitat along the southeastern front, approximately 25 km distant. The species’ relative abundance in previously and newly identified pine–juniper–shrub habitats was similar. Virginia’s Warbler occurrence was positively associated with shrub cover (primarily mountain-mahogany, Cercocarpus montanus), pine overstory, and slopes of \u3e15°. Its association with the Spotted Towhee (Pipilo maculatus) was negative, with the Yellow-rumped Warbler (Setophaga coronata) tended toward positive, and with the Dusky Flycatcher (Empidonax oberholseri) was variable (negative along the southwestern front but weakly positive across all sites). These data extend the documented breeding range of Virginia’s Warbler in South Dakota by more than 20 km to the southeast. To clarify conservation priorities for this species at the northeastern limit of its range, future studies should delineate local and landscape-level characteristics of this population’s habitat more precisely and address its source–sink population dynamics

    Effects of biceps tension and superior humeral head translation on the glenoid labrum

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    We sought to understand the effects of superior humeral head translation and load of the long head of biceps on the pathomechanics of the superior glenoid labrum by predicting labral strain. Using micro‐CT cadaver images, a finite element model of the glenohumeral joint was generated, consisting of humerus, glenoid bone, cartilages, labrum, and biceps tendon. A glenohumeral compression of 50 N and biceps tensions of 0, 22, 55, and 88 N were applied. The humeral head was superiorly translated from 0 to 5 mm in 1‐mm increments. The highest labral strain occurred at the interface with the glenoid cartilage and bone beneath the origin of the biceps tendon. The maximum strain was lower than the reported failure strain. The humeral head motion had relatively greater effect than biceps tension on the increasing labral strain. This supports the mechanistic hypothesis that superior labral lesions result mainly from superior migration of the humeral head, but also from biceps tension. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1424–1429, 2014.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108670/1/jor22688.pd

    Effects of biceps tension on the torn superior glenoid labrum

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    The purpose of this study was to evaluate the role of the tension on the long head of the biceps tendon in the propagation of SLAP tears by studying the mechanical behavior of the torn superior glenoid labrum. A previously validated finite element model was extended to include a glenoid labrum with type II SLAP tears of three different sizes. The strain distribution within the torn labral tissue with loading applied to the biceps tendon was investigated and compared to the inact and unloaded conditions. The anterior and posterior edges of each SLAP tear experienced the highest strain in the labrum. Labral strain increased with increasing biceps tension. This effect was stronger in the labrum when the size of the tear exceeded the width of the biceps anchor on the superior labrum. Thus, this study indicates that biceps tension influences the propagation of a SLAP tear more than it does the initiation of a tear. Additionally, it also suggests that the tear size greater than the biceps anchor site as a criterion in determining optimal treatment of a type II SLAP tear. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1545–1551, 2015.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113101/1/jor22888.pd

    A stochastic movement simulator improves estimates of landscape connectivity

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    Acknowledgments This publication issued from the project TenLamas funded by the French Ministère de l'Energie, de l'Ecologie, du Développement Durable et de la Mer through the EU FP6 BiodivERsA Eranet; by the Agence Nationale de la Recherche (ANR) through the open call INDHET and 6th extinction MOBIGEN to V. M. Stevens, M. Baguette, and A. Coulon, and young researcher GEMS (ANR-13-JSV7-0010-01) to V. M. Stevens and M. Baguette; and by a VLIR-VLADOC scholarship awarded to J. Aben. L. Lens, J. Aben, D. Strubbe, and E. Matthysen are grateful to the Research Foundation Flanders (FWO) for financial support of fieldwork and genetic analysis (grant G.0308.13). V. M. Stevens and M. Baguette are members of the “Laboratoire d'Excellence” (LABEX) entitled TULIP (ANR-10-LABX-41). J. M. J. Travis and S. C. F. Palmer also acknowledge the support of NERC. A. Coulon and J. Aben contributed equally to the work.Peer reviewedPublisher PD

    CESR Conversion Damping Ring Studies of Electron Cloud Instabilities (CESR-TA)

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    In the International Linear Collider, two linear accelerators will accelerate bunches of positrons and electrons to over a hundred billion electron volts and collide them in a central detector. In order to obtain useful collision rates, the bunches, each containing twenty billion particles, must be compressed to a cross section of a few nanometers by a few hundred nanometers. In order to prepare these ultra high density bunches, damping rings (DRs) are employed before the linear accelerators. The DRs take the high emittance bunches that are provided by the electron and positron sources and, through the process of radiation damping, squeeze them into ultra low emittance beams that are ready for the main linear accelerators. In the damping rings, a number of effects can prevent the successful preparation of the beams. In the electron ring, an effect known as the fast ion instability can lead to beam growth and, in the positron ring, the build-up of an electron cloud (EC), which interacts with the circulating bunches, can produce the same effect. EC build-up and the subsequent interaction of the cloud with the positron beam in the DR have been identified as major risks for the successful construction of a linear collider. The CESRTA research program at the Cornell Electron Storage Ring (CESR) was developed in order to study the build-up of the EC, the details of its impact on ultra low emittance beams, as well as methods to mitigate the impact of the cloud. In the DR, the EC forms when synchrotron photons radiated from the circulating beam strike the walls of the vacuum chamber, resulting in the emission of photoelectrons. These low energy electrons can be accelerated across the vacuum chamber by the electric field of the beam, and strike the walls, causing the emission of secondary electrons. The secondary electrons are subsequently accelerated into the walls yet again via the same mechanism. The result is that the EC can rapidly begin to fill the vacuum chamber. In an electron DR, the EC build-up is limited by the Coulomb repulsion. But in a positron ring, the electrons are pulled into the potential well of the beam. The resulting interaction of the circulating bunches of positrons with the EC that ultimately limits DR performance. Typically we store long trains of closely space bunches in the damping ring. The interaction of stored beam and the EC that is generated by the long train is manifested by different mechanisms: (1) The cloud focuses the beam, which causes a tune shift that increases along the bunch train as the cloud density increases. (2) The cloud electrons couple the motion of bunches along a train. Transverse motion of a leading bunch is transferred to the cloud, and subsequently to a trailing bunch which can result in a multi-bunch instability. (3) The cloud couples the positrons in the head of the bunch to those in the tail of the same bunch, which can excite a 'head-tail' instability. (4) The nonlinear fields of the EC can lead to emittance growth before the onset of instabilities. The CESRTA collaboration, which includes researchers from Cornell University's Laboratory for Elementary-Particle Physics as well as more than 50 senior staff members from over a dozen accelerator laboratories and universities around the world, has operated CESR as a damping ring for the past three years to study these EC effects. A range of specialized instrumentation has been deployed to study the local build-up of the cloud in the vacuum chambers as well as the complicated dynamics exhibited when the beam and the EC interact. The program has significantly advanced our understanding of these issues and has helped identify the most promising methods to mitigate the impact of the EC on the DR beams. It has pointed the way towards a DR design that can meet the stringent specifications of the ILC

    Stroke Research Staff's Experiences of Seeking Consent from People with Communication Difficulties: Results of a National Online Survey

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    Background: The process of obtaining informed consent from people with communication difficulties is challenging. An online survey was conducted to explore the experiences of stroke research staff in seeking consent from this population. Objectives: To identify how stroke research staff seek consent from people with communication difficulties, potential barriers to effective practice, and ways to improve practice. Methods: All research staff working for the National Institute for Health Research Stroke Research Network in England were invited to complete an online questionnaire. Data were collected anonymously between March and June 2013. Quantitative data were analyzed using descriptive statistics, and qualitative data were coded using thematic analysis. Results: Seventy-five research staff responded, corresponding to a response rate of 10%. There were 97% who had sought consent from people with communication difficulties and 52% did this regularly; 65% had received training in consenting this population. Most staff were aware of appropriate methods for supporting communication needs, but only 18% regularly used accessible information and 35% regularly used augmentative communication techniques. Lack of specific training and lack of access to ethically approved materials were suggested barriers to using these methods. Respondents indicated that people with impaired communication may be excluded from the consent process because they are not eligible for inclusion in studies or because assent is obtained from third parties. Conclusions: For research staff to work more effectively with this population, study protocols need to be more inclusive of people with communication difficulties, and staff need better access to ethically approved, accessible communication resources and appropriate training

    Giant flagellins form thick flagellar filaments in two species of marine γ-proteobacteria

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    Flagella, the primary means of motility in bacteria, are helical filaments that function as microscopic propellers composed of thousands of copies of the protein flagellin. Here, we show that many bacteria encode “giant” flagellins, greater than a thousand amino acids in length, and that two species that encode giant flagellins, the marine γ-proteobacteria Bermanella marisrubri and Oleibacter marinus, produce monopolar flagellar filaments considerably thicker than filaments composed of shorter flagellin monomers. We confirm that the flagellum from B. marisrubri is built from its giant flagellin. Phylogenetic analysis reveals that the mechanism of evolution of giant flagellins has followed a stepwise process involving an internal domain duplication followed by insertion of an additional novel insert. This work illustrates how “the” bacterial flagellum should not be seen as a single, idealised structure, but as a continuum of evolved machines adapted to a range of niches

    Methods for Capturing, Marking, and Estimating Survival of Northern Bobwhite Chicks (Poster Abstract)

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    Lack of techniques to capture, mark, and observe chicks from hatch to fall has hindered our ability to understand this critical life stage of northern bobwhite (Colinus virginianus) and other galliforms. We present 2 methods for capturing wild, free-ranging northern bobwhite chicks associated with a radiomarked adult and demonstrate application of capture-recapture estimators. Both capture techniques involve monitoring radiomarked adults, locating nests, determining date of hatch, and then locating roosting adults with broods prior to sunrise during the pre-flight period (1–12 days post-hatch). The first technique involves erecting a temporary circular fence around the roosting radio-marked bird and brood, securing the edges with dirt, and systematically clearing all vegetation and ground debris until chicks are captured. The second technique involves placing a temporary fence in a ‘‘V’’ formation with a small mesh funnel trap placed at the apex. Birds are then ‘‘corralled’’ into the funnel trap. We used both methods during the breeding seasons of 1997–99. Overall, we captured 762 chicks from 137 broods. Of 131 capture attempts using the ring method, 18.3% (n = 24) were complete failures, 13.7% (n = 18) resulted in partial capture, whereas 68% (n = 89) resulted in complete capture. Using the funnel method, 22.2% (n = 2) of attempts were complete failures, 22.2% (n = 2) resulted in partial captures, and 55.6% (n = 5) resulted in complete brood capture. Captured chicks can be permanently and uniquely marked using monel patagial wing bands. We demonstrate application of capture-recapture models in program MARK to estimate chick survival from hatch to recruitment in the fall population (Oct 1)

    Patient and caregiver values, beliefs and experiences when considering home dialysis as a treatment option: a semi-structured interview study

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    Background Home dialysis can offer improved quality of life and economic benefits compared with facility dialysis. Yet the uptake of home dialysis remains low around the world, which may be partly due to patients' lack of knowledge and barriers to shared and informed decision-making. We aimed to describe patient and caregiver values, beliefs and experiences when considering home dialysis, to inform strategies to align policy and practice with patients' needs. Methods Semi-structured interviews with adult patients with chronic kidney disease Stage 4–5D (on dialysis <1 year) and their caregivers, recruited from three nephrology centres in New Zealand. Transcripts were analysed thematically. Results In total, 43 patients [pre-dialysis (n = 18), peritoneal dialysis (n = 13), home haemodialysis (n = 4) and facility haemodialysis (n = 9)] and 9 caregivers participated. We identified five themes related to home dialysis: lacking decisional power (complexity of information, limited exposure to home dialysis, feeling disempowered, deprived of choice, pressure to choose), sustaining relationships (maintaining cultural involvement, family influence, trusting clinicians, minimizing social isolation), reducing lifestyle disruption (sustaining employment, avoiding relocation, considering additional expenses, seeking flexible schedules, creating free time), gaining confidence in choice (guarantee of safety, depending on professional certainty, reassurance from peers, overcoming fears) and maximizing survival. Conclusions To engage and empower patients and caregivers to consider home dialysis, a stronger emphasis on the development of patient-focused educational programmes and resources is suggested. Pre-dialysis and home dialysis programmes that address health literacy and focus on cultural and social values may reduce fears and build confidence around decisions to undertake home dialysis. Financial burdens may be minimized through provision of reimbursement programmes, employment support and additional assistance for patients, particularly those residing in remote areas

    Distributed Cognition in Cancer Treatment Decision Making: An Application of the DECIDE Decision-Making Styles Typology

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    Distributed cognition occurs when cognitive and affective schemas are shared between two or more people during interpersonal discussion. Although extant research focuses on distributed cognition in decision making between health care providers and patients, studies show that caregivers are also highly influential in the treatment decisions of patients. However, there are little empirical data describing how and when families exert influence. The current article addresses this gap by examining decisional support in the context of cancer randomized clinical trial (RCT) decision making. Data are drawn from in-depth interviews with rural, Appalachian cancer patients (N = 46). Analysis of transcript data yielded empirical support for four distinct models of health decision making. The implications of these findings for developing interventions to improve the quality of treatment decision making and overall well-being are discussed
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