598 research outputs found

    A NASTRAN primer for the analysis of rotating flexible blades

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    This primer provides documentation for using MSC NASTRAN in analyzing rotating flexible blades. The analysis of these blades includes geometrically nonlinear (large displacement) analysis under centrifugal loading, and frequency and mode shape (normal modes) determination. The geometrically nonlinear analysis using NASTRAN Solution sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. A sample problem with the complete NASTRAN input data is included. Items unique to rotating blade analyses, such as setting angle and centrifugal softening effects are emphasized

    Ground water and surface water under stress

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    Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.Includes bibliographical references.Traditionally, the metered monitoring and quantification of water use by individual irrigators in Alberta has been almost non-existent. As the increasing competition for a limited and finite resource has become much more of a reality in some major river basins, this water management tool is now receiving much more critical attention. In response to that emerging need and a very specific water-sharing issue, a pilot water use-measuring project was devised and implemented within the concentration of just over 6,500 acres of private irrigation along the Canadian reach of the Milk River. This river basin is a unique watershed, rising within the foothills of western Montana, flowing northeastward into and across the southern-most region of Alberta and then back southeastward into northeastern Montana. It is associated with international water management agreements that are a challenge to administer effectively. A rigorous monitoring of water diversions and river flows is critical for the effective administration of the international water-sharing agreement. Of particular concern, for example, is the need to accurately quantify Canadian withdrawals of water that may have originally been diverted up-stream as American allocations. As a result, the Alberta Department of Environment has initiated a project to track instantaneous irrigation water withdrawals along the Canadian reach of the Milk River and have that information reported on a near real-time basis through a designated website

    Stress and immunological response of heifers divergently ranked for residual feed intake following an adrenocorticotropic hormone challenge

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    peer-reviewedBackground When an animal is exposed to a stressor, metabolic rate, energy consumption and utilisation increase primarily through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Changes to partitioning of energy by an animal are likely to influence the efficiency with which it is utilised. Therefore, this study aimed to determine the physiological stress response to an exogenous adrenocorticotropic hormone (ACTH) challenge in beef heifers divergently ranked on phenotypic residual feed intake (RFI). Results Data were collected on 34 Simmental weaning beef heifers the progeny of a well characterized and divergently bred RFI suckler beef herd. Residual feed intake was determined on each animal during the post-weaning stage over a 91-day feed intake measurement period during which they were individually offered adlibitum grass silage and 2 kg of concentrate per head once daily. The 12 highest [0.34 kg DM/d] and 12 lowest [−0.48 kg DM/d] ranking animals on RFI were selected for use in this study. For the physiological stress challenge heifers (mean age 605 ± 13 d; mean BW 518 ± 31.4 kg) were fitted aseptically with indwelling jugular catheters to facilitate intensive blood collection. The response of the adrenal cortex to a standardised dose of ACTH (1.98 IU/kg metabolic BW0.75) was examined. Serial blood samples were analysed for plasma cortisol, ACTH and haematology variables. Heifers differing in RFI did not differ (P = 0.59) in ACTH concentrations. Concentration of ACTH peaked (P < 0.001) in both RFI groups at 20 min post-ACTH administration, following which concentration declined to baseline levels by 150 min. Similarly, cortisol systemic profile peaked at 60 min and concentrations remained continuously elevated for 150 min. A RFI × time interaction was detected for cortisol concentrations (P = 0.06) with high RFI heifers had a greater cortisol response than Low RFI from 40 min to 150 min relative to ACTH administration. Cortisol response was positively associated with RFI status (r = 0.32; P < 0.01). No effect of RFI was evident for neutrophil, lymphocytes, monocyte, eosinophils and basophil count. Plasma red blood cell number (6.07 vs. 6.23; P = 0.02) and hematocrit percentage (23.2 vs. 24.5; P = 0.02) were greater for low than high RFI animals. Conclusions Evidence is provided that feed efficiency is associated with HPA axis function and susceptibility to stress, and responsiveness of the HPA axis is likely to contribute to appreciable variation in the efficiency feed utilisation of cattle

    User observations on information sharing (corporate knowledge and lessons learned)

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    The sharing of 'corporate knowledge' and lessons learned in the NASA aerospace community has been identified by Johnson Space Center survey participants as a desirable tool. The concept of the program is based on creating a user friendly information system that will allow engineers, scientists, and managers at all working levels to share their information and experiences with other users irrespective of location or organization. The survey addresses potential end uses for such a system and offers some guidance on the development of subsequent processes to ensure the integrity of the information shared. This system concept will promote sharing of information between NASA centers, between NASA and its contractors, between NASA and other government agencies, and perhaps between NASA and institutions of higher learning

    What doesn't kill you makes you stranger: Dipeptidyl peptidase-4 (CD26) proteolysis differentially modulates the activity of many peptide hormones and cytokines generating novel cryptic bioactive ligands

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    Dipeptidyl peptidase 4 (DPP4) is an exopeptidase found either on cell surfaces where it is highly regulated in terms of its expression and surface availability (CD26) or in a free/circulating soluble constitutively available and intrinsically active form. It is responsible for proteolytic cleavage of many peptide substrates. In this review we discuss the idea that DPP4-cleaved peptides are not necessarily inactivated, but rather can possess either a modified receptor selectivity, modified bioactivity, new antagonistic activity, or even a novel activity relative to the intact parent ligand. We examine in detail five different major DPP4 substrates: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide tyrosine-tyrosine (PYY), and neuropeptide Y (NPY), and stromal derived factor 1 (SDF-1 aka CXCL12). We note that discussion of the cleaved forms of these five peptides are underrepresented in the research literature, and are both poorly investigated and poorly understood, representing a serious research literature gap. We believe they are understudied and misinterpreted as inactive due to several factors. This includes lack of accurate and specific quantification methods, sample collection techniques that are inherently inaccurate and inappropriate, and a general perception that DPP4 cleavage inactivates its ligand substrates. Increasing evidence points towards many DPP4-cleaved ligands having their own bioactivity. For example, GLP-1 can work through a different receptor than GLP-1R, DPP4-cleaved GIP can function as a GIP receptor antagonist at high doses, and DPP4-cleaved PYY, NPY, and CXCL12 can have different receptor selectivity, or can bind novel, previously unrecognized receptors to their intact ligands, resulting in altered signaling and functionality. We believe that more rigorous research in this area could lead to a better understanding of DPP4’s role and the biological importance of the generation of novel cryptic ligands. This will also significantly impact our understanding of the clinical effects and side effects of DPP4-inhibitors as a class of anti-diabetic drugs that potentially have an expanding clinical relevance. This will be specifically relevant in targeting DPP4 substrate ligands involved in a variety of other major clinical acute and chronic injury/disease areas including inflammation, immunology, cardiology, stroke, musculoskeletal disease and injury, as well as cancer biology and tissue maintenance in aging

    Process evaluation of a sport-for-health intervention to prevent smoking amongst primary school children: SmokeFree Sports

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    Background: SmokeFree Sports (SFS) was a multi-component sport-for-health intervention aiming at preventing smoking among nine to ten year old primary school children from North West England. The purpose of this study was to evaluate the process and implementation of SFS, examining intervention reach, dose, fidelity, acceptability and sustainability, in order to understand the feasibility and challenges of delivering such interventions and inform interpretations of intervention effectiveness.&nbsp; Methods: Process measures included: booking logs, 18 focus groups with children (n=95), semi-structured interviews with teachers (n=20) and SFS coaches (n=7), intervention evaluation questionnaires (completed by children, n=1097; teachers, n=50), as well direct observations (by researchers, n=50 observations) and self-evaluations (completed by teachers, n=125) of intervention delivery (e.g. length of sessions, implementation of activities as intended, children's engagement and barriers). Descriptive statistics and thematic analysis were applied to quantitative and qualitative data, respectively.&nbsp; Results: Overall, SFS reached 30.8% of eligible schools, with 1073 children participating in the intervention (across 32 schools). Thirty-one schools completed the intervention in full. Thirty-three teachers (55% female) and 11 SFS coaches (82% male) attended a bespoke SFS training workshop. Disparities in intervention duration (range=126 to 201 days), uptake (only 25% of classes received optional intervention components in full), and the extent to which core (mean fidelity score of coaching sessions=58%) and optional components (no adaptions made=51% of sessions) were delivered as intended, were apparent. Barriers to intervention delivery included the school setting and children's behaviour and knowledge. SFS was viewed positively (85% and 82% of children and teachers, respectively, rated SFS five out of five) and recommendations to increase school engagement were provided.&nbsp; Conclusion: SFS was considered acceptable to children, teachers and coaches. Nevertheless, efforts to enhance intervention reach (at the school level), teachers' engagement and sustainability must be considered. Variations in dose and fidelity likely reflect challenges associated with complex intervention delivery within school settings and thus a flexible design may be necessary. This study adds to the limited scientific evidence base surrounding sport-for-health interventions and their implementation, and suggests that such interventions offer a promising tool for engaging children in activities which promote their health

    Vitamin D Status and Bone and Connective Tissue Turnover in Brown Bears (Ursus arctos) during Hibernation and the Active State

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    BACKGROUND: Extended physical inactivity causes disuse osteoporosis in humans. In contrast, brown bears (Ursus arctos) are highly immobilised for half of the year during hibernation without signs of bone loss and therefore may serve as a model for prevention of osteoporosis. AIM: To study 25-hydroxy-vitamin D (25OHD) levels and bone turnover markers in brown bears during the hibernating state in winter and during the active state in summer. We measured vitamin D subtypes (D₂ and D₃), calcitropic hormones (parathyroid hormone [PTH], 1,25-dihydroxy-vitamin D [1,25(OH)₂D]) and bone turnover parameters (osteocalcin, ICTP, CTX-I), PTH, serum calcium and PIIINP. MATERIAL AND METHODS: We drew blood from seven immobilised wild brown bears during hibernation in February and in the same bears while active in June. RESULTS: Serum 25-hydroxy-cholecalciferol (25OHD₃) was significantly higher in the summer than in the winter (22.8±4.6 vs. 8.8±2.1 nmol/l, two tailed p-2p = 0.02), whereas 25-hydroxy-ergocalciferol (25OHD₂) was higher in winter (54.2±8.3 vs. 18.7±1.7 nmol/l, 2p<0.01). Total serum calcium and PTH levels did not differ between winter and summer. Activated 1,25(OH)₂D demonstrated a statistically insignificant trend towards higher summer levels. Osteocalcin levels were higher in summer than winter, whereas other markers of bone turnover (ICTP and CTX-I) were unchanged. Serum PIIINP, which is a marker of connective tissue and to some degree muscle turnover, was significantly higher during summer than during winter. CONCLUSIONS: Dramatic changes were documented in the vitamin D₃/D₂ ratio and in markers of bone and connective tissue turnover in brown bears between hibernation and the active state. Because hibernating brown bears do not develop disuse osteoporosis, despite extensive physical inactivity we suggest that they may serve as a model for the prevention of this disease

    NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

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    This paper presents three-dimensional prognostic O<sub>3</sub> simulations with parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphere forecast model. We compare 5-day NOGAPS-ALPHA hindcasts of stratospheric O<sub>3</sub> with satellite and DC-8 aircraft measurements for two cases during the SOLVE II campaign: (1) the cold, isolated vortex during 11-16 January 2003; and (2) the rapidly developing stratospheric warming of 17-22 January 2003. In the first case we test three different photochemistry parameterizations. NOGAPS-ALPHA O<sub>3</sub> simulations using the NRL-CHEM2D parameterization give the best agreement with SAGE III and POAM III profile measurements. 5-day NOGAPS-ALPHA hindcasts of polar O<sub>3</sub> initialized with the NASA GEOS4 analyses produce better agreement with observations than do the operational ECMWF O<sub>3</sub> forecasts of case 1. For case 2, both NOGAPS-ALPHA and ECMWF 114-h forecasts of the split vortex structure in lower stratospheric O<sub>3</sub> on 21 January 2003 show comparable skill. Updated ECMWF O<sub>3</sub> forecasts of this event at hour 42 display marked improvement from the 114-h forecast; corresponding updated 42-hour NOGAPS-ALPHA prognostic O<sub>3</sub> fields initialized with the GEOS4 analyses do not improve significantly. When NOGAPS-ALPHA prognostic O<sub>3</sub> is initialized with the higher resolution ECMWF O<sub>3</sub> analyses, the NOGAPS-ALPHA 42-hour lower stratospheric O<sub>3</sub> fields closely match the operational 42-hour ECMWF O<sub>3</sub> forecast of the 21 January event. We find that stratospheric O<sub>3</sub> forecasts at high latitudes in winter can depend on both model initial conditions and the treatment of photochemistry over periods of 1-5 days. Overall, these results show that the new O<sub>3</sub> initialization, photochemistry parameterization, and spectral transport in the NOGAPS-ALPHA NWP model can provide reliable short-range stratospheric O<sub>3</sub> forecasts during Arctic winter
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