1,572 research outputs found
Stellar Polarimetry: Where Are We and Where Are We Going?
On the final day of the Stellar Polarimetry conference, participants split up
into three "breakout sessions" to discuss the future of the field in the areas
of instrumentation, upcoming opportunities, and community priorities. This
contribution compiles the major recommendations arising from each breakout
session. We hope that the polarimetric community will find these ideas useful
as we consider how to maintain the vitality of polarimetry in the coming years.Comment: 7 pages, published in proceedings of "Stellar Polarimetry: From Birth
to Death" (Madison, WI, June 2011
Structure of Mandelate Racemase with Bound Intermediate Analogues Benzohydroxamate and Cupferron
Mandelate racemase (MR, EC 5.1.2.2) from Pseudomonas putida catalyzes the Mg2+-dependent interconversion of the enantiomers of mandelate, stabilizing the altered substrate in the transition state by 26 kcal/mol relative to the substrate in the ground state. To understand the origins of this binding discrimination, we determined the X-ray crystal structures of wild-type MR complexed with two analogues of the putative aci-carboxylate intermediate, benzohydroxamate and Cupferron, to 2.2-Å resolution. Benzohydroxamate is shown to be a reasonable mimic of the transition state and/or intermediate because its binding affinity for 21 MR variants correlates well with changes in the free energy of transition state stabilization afforded by these variants. Both benzohydroxamate and Cupferron chelate the active site divalent metal ion and are bound in a conformation with the phenyl ring coplanar with the hydroxamate and diazeniumdiolate moieties, respectively. Structural overlays of MR complexed with benzohydroxamate, Cupferron, and the ground state analogue (S)-atrolactate reveal that the para carbon of the substrate phenyl ring moves by 0.8−1.2 Å between the ground state and intermediate state, consistent with the proposal that the phenyl ring moves during MR catalysis while the polar groups remain relatively fixed. Although the overall protein structure of MR with bound intermediate analogues is very similar to that of MR with bound (S)-atrolactate, the intermediate−Mg2+ distance becomes shorter, suggesting a tighter complex with the catalytic Mg2+. In addition, Tyr 54 moves closer to the phenyl ring of the bound intermediate analogues, contributing to an overall constriction of the active site cavity. However, site-directed mutagenesis experiments revealed that the role of Tyr 54 in MR catalysis is relatively minor, suggesting that alterations in enzyme structure that contribute to discrimination between the altered substrate in the transition state and the ground state by this proficient enzyme are extremely subtle
Genome-wide association study in two cohorts from a multi-generational mouse advanced intercross line highlights the difficulty of replication due to study-specific heterogeneity
There has been extensive discussion of the Replication Crisis in many fields, including genome-wide association studies
South Dakota Fisheries: An Evaluation of a Chemical Immersion Marking Technique for Juvenile Yellow Perch and Application to a Stocking Assessment of Marsh-Reared Yellow Perch into Eastern South Dakota Lakes
Currently, yellow perch Perca flavescens stocking needs in South Dakota are met by intensive trap and transfer of juvenile and adult perch. The success of these stocking efforts is largely undocumented, primarily due to problems in distinguishing yellow perch produced within the recipient water body and stocked perch. We first developed a transfer-tank marking protocol to determine immersion duration and optimal concentration of oxytetracycline (OTC) hydrochloride needed to produce an effective mark. Then we validated the protocol for adult yellow perch and determined the persistence of OTC in edible muscle tissue. Marking results indicated that satisfactory OTC marks may be obtained in juvenile yellow perch using 600- to 700-ppm OTC for an immersion period of 6 to 8 h. OTC marks were evident in juvenile yellow perch otoliths and dorsal spines checked at 3 months post-immersion. Mark quality was observed to be slightly better in juvenile dorsal spines than otoliths. OTC marks in adult yellow perch were detectable at otolith margins at 9 d post-immersion. Adult muscle tissues were analyzed with high pressure liquid chromatography to quantify OTC residues. A nonlinear model (In epi-OTC [~g g-I] = 0.960 - 0.389*In time [h]; r\u27- = 0.99) describing the combined OTC base/epi residue relation to time indicated that no more than 0.5 ~g OTC g-I should be present at 73 h following immersion
Recommended from our members
Place - the final frontier: exploring the outer reaches of collaborative agency using the Japanese concept of Ba
Scholars within the field of Leadership-as-Practice (LAP) address the way that individuals
‘transcend their own immediate embeddedness’ to achieve volitional coherence known as
collaborative agency. The process of collaborative agency is described as inseparable from LAP
yet it remains a nascent field of enquiry requiring additional empirical research.
This paper presents an investigation of collaborative agency through an abductive case study
using video ethnography and interviews. To interpret our results, we turn to the Japanese
ideogram for ‘place’, known as ‘Ba’. Rather than a physical reality, Ba is considered an
existential space in which leadership groups weave together to create and ripen collaborative
agency. Ba guides us to look across and around a group and its socio material practice.
We find that collaborative agency is trans-subjective in nature and sits on a spectrum on which
we identify the outer reaches, from one end where Ba is woven through to the other end, called
Collapse. We suggest that the place of leadership is within the warp and weft of collaborative
agency, including but not limited to a special place woven in Ba where collaborative agency is
high and where the group reports they are able to transcend their individualism
Designing open access, educational resources / Développer des ressources éducatives en libre accès
The recent bourgeoning of open educational resources has meant greater access to materials with open licenses in the public domain than ever before. Open educational resources are learning tools, such as textbooks, that are freely available and typically accessed online. Despite the expansion of open educational resources, many educators are still unacquainted with the nature and process of producing such resources. The purpose of this discussion paper is to share our experience in developing an open educational e-textbook for students in post-secondary programs for nursing and other health professions while highlighting practical tips for educators. The exemplar referenced in this paper focuses on vital signs’ measurement, a familiar concept for nurse educators, and a topic ubiquitous in healthcare. This paper is suited for any user curious about designing open educational resources with consideration of key elements to produce quality and educational resources that support excellence in nursing pedagogy. We begin by providing a background to our specific project followed by a discussion of the planning phase, the design phase, and other considerations. The e-textbook falls under a Creative Commons license and can be accessed for free by educators and learners.
Résumé
Le développement récent de ressources éducatives en libre accès a permis une accessibilité beaucoup plus grande, comme jamais auparavant, au matériel avec licences ouvertes dans le domaine public. Les ressources éducatives en libre accès sont des outils d’apprentissage, comme les manuels scolaires, qui sont offerts gratuitement et qui sont généralement accessibles en ligne. En dépit de la prolifération des ressources éducatives libres, bon nombre de professeurs sont toujours peu familiers avec la nature et le processus de production de telles ressources. L’objectif de ce texte de discussion est de partager notre expérience du développement d’un e-manuel de formation en libre accès, pour les étudiants inscrits dans les programmes postsecondaires pour la profession infirmière et les autres professions de la santé, tout en soulignant des conseils pratiques pour les professeurs. L’exemple, cité en référence dans ce texte, est axé sur la prise des signes vitaux, un concept familier aux infirmières enseignantes et un sujet omniprésent dans le domaine de la santé. Cet article convient à toute personne curieuse d’en apprendre davantage sur la conception des ressources éducatives en libre accès en tenant compte d’éléments clés afin de produire des ressources éducatives de qualité qui appuient l’excellence de la pédagogie en soins infirmiers. Nous établissons d’abord le contexte du projet particulier suivi d’une discussion sur la phase de planification, la phase de conception et sur d’autres éléments à considérer. Le e-manuel relève d’une licence Creative Commons et est accessible gratuitement pour les professeurs et les étudiants
Prevalence of Fibromyalgia: A Population‐Based Study in Olmsted County, Minnesota, Utilizing the Rochester Epidemiology Project
Objective To estimate and compare the prevalence of fibromyalgia by 2 different methods in Olmsted County, Minnesota. Methods The first method was a retrospective review of medical records of potential cases of fibromyalgia in Olmsted County using the Rochester Epidemiology Project (from January 1, 2005, to December 31, 2009) to estimate the prevalence of diagnosed fibromyalgia in clinical practice. The second method was a random survey of adults in Olmsted County using the fibromyalgia research survey criteria to estimate the percentage of responders who met the fibromyalgia research survey criteria. Results Of the 3,410 potential patients identified by the first method, 1,115 had a fibromyalgia diagnosis documented in the medical record by a health care provider. The age‐ and sex‐adjusted prevalence of diagnosed fibromyalgia by this method was 1.1%. By the second method, of the 2,994 people who received the survey by mail, 830 (27.6%) responded and 44 (5.3%) met the fibromyalgia research survey criteria. The age‐ and sex‐adjusted prevalence of fibromyalgia in the general population of Olmsted County by this method was estimated at 6.4%. Conclusion To the best of our knowledge, this is the first report of the rate at which fibromyalgia is being diagnosed in a community. This is also the first report of prevalence as assessed by the fibromyalgia research survey criteria. Our results suggest that patients, particularly men, who meet the fibromyalgia research survey criteria are unlikely to have been given a diagnosis of fibromyalgia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97488/1/21896_ftp.pd
Global patterns of diapycnal mixing from measurements of the turbulent dissipation rate
The authors present inferences of diapycnal diffusivity from a compilation of over 5200 microstructure profiles. As microstructure observations are sparse, these are supplemented with indirect measurements of mixing obtained from (i) Thorpe-scale overturns from moored profilers, a finescale parameterization applied to (ii) shipboard observations of upper-ocean shear, (iii) strain as measured by profiling floats, and (iv) shear and strain from full-depth lowered acoustic Doppler current profilers (LADCP) and CTD profiles. Vertical profiles of the turbulent dissipation rate are bottom enhanced over rough topography and abrupt, isolated ridges. The geography of depth-integrated dissipation rate shows spatial variability related to internal wave generation, suggesting one direct energy pathway to turbulence. The global-averaged diapycnal diffusivity below 1000-m depth is O(10?4) m2 s?1 and above 1000-m depth is O(10?5) m2 s?1. The compiled microstructure observations sample a wide range of internal wave power inputs and topographic roughness, providing a dataset with which to estimate a representative global-averaged dissipation rate and diffusivity. However, there is strong regional variability in the ratio between local internal wave generation and local dissipation. In some regions, the depth-integrated dissipation rate is comparable to the estimated power input into the local internal wave field. In a few cases, more internal wave power is dissipated than locally generated, suggesting remote internal wave sources. However, at most locations the total power lost through turbulent dissipation is less than the input into the local internal wave field. This suggests dissipation elsewhere, such as continental margins
Personal non-commercial use only
ABSTRACT. Objective. To determine the incidence and prevalence of sporadic inclusion body myositis (sIBM) and polymyositis (PM) in a population-based study. Methods. Charts of patients with myositis in Olmsted County, Minnesota, USA, from 1981 to 2000 were reviewed. Results. For sIBM, the age-and sex-adjusted incidence rates per 100,000 were 0.79 (95% confidence interval = 0.24-1.35), and for PM, 0.41 (95% CI 0.08-0.73). The age-and sex-adjusted prevalence rates per 100,000 were 7.06 (95% CI 0.87-13.24) for sIBM and 3.45 (95% CI 0.00-7.35) for PM. Conclusion. The incidence and prevalence rates for sIBM are higher than previously reported
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