2,974 research outputs found
KINEMATIC ANALYSIS OF ELITE JAVELIN THROWERS
Research on various aspects of the throwing motion has indicated it to be a very complex movement (Atwater, 1979). Certain kinematic parameters appear t o be common determinants of successful performance regardless of the nature of the throwing task. Under ideal conditions (i.e., ignoring air resistance and the type of implement being thrown) the path, and hence distance thrown, is determined by the angle, height and velocity of release. Such an ideal analysis needs some modification for situations in which aerodynamics are considered. Since the release phase of the javelin throw encompasses these common throwing components as well as obvious aerodynamic influences, quantification of release characteristics which establish the initial conditions of f light is important
The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation
Seasonal surveys were conducted during 1998–1999 in Baja California, Baja California Sur, Sonora, and Sinaloa to determine the extent and activities of artisanal elasmobranch fisheries in the Gulf of California. One hundred and forty–seven fishing sites, or camps, were documented, the majority of which (n = 83) were located in Baja California Sur. Among camps with adequate fisheries information, the great majority (85.7%) targeted elasmobranchs during some part of the year. Most small, demersal sharks and rays were landed in mixed species fisheries that also targeted demersal teleosts, but large sharks were usually targeted in directed drift gillnet or, to a lesser extent, surface longline fisheries. Artisanal fishermen were highly opportunistic, and temporally switched targets depending on the local productivity of teleost, invertebrate, and elasmobranch fishery resources. Major fisheries for small sharks ( 1.5 m, “tiburón”) were minor components of artisanal elasmobranch fisheries in Sonora and Sinaloa, but were commonly targeted during summer and early autumn in Baja California and Baja California Sur. The pelagic thresher shark (Alopias pelagicus) and silky shark (Carcharhinus falciformis) were most commonly landed in Baja California, whereas a diverse assemblage of pelagic and large coastal sharks was noted among Baja California Sur landings. Rays dominated summer landings in Baja California and Sinaloa, when elevated catch rates of the shovelnose guitarfish (Rhinobatos productus, 13.2 individuals/vessel/trip) and golden cownose ray (Rhinoptera steindachneri, 11.1 individuals/vesse/trip) primarily supported the respective fisheries. The Sonoran artisanal elasmobranch fishery was the most expansive recorded during this study, and rays (especially R. productus) dominated spring and summer landings in this state. Seasonal catch rates of small demersal sharks and rays were considerably greater in Sonora than in other surveyed states. Many tiburón populations (e.g., C. leucas, C. limbatus, C. obscurus, Galeocerdo cuvier) have likely been overfished, possibly shifting effort towards coastal populations of cazón and rays. Management recommendations, including conducting demographic analyses using available life history data, determining and protecting nursery areas, and enacting seasonal closures in areas of elasmobranch aggregation (e.g., reproduction, feeding), are proposed. Without effective, enforceable management to sustain or rebuild targeted elasmobranch populations in the Gulf of California, collapse of many fisheries is a likely outcome. (PDF contains 243 pages
A Comparison of Data Sources for Motor Vehicle Crash Characteristic Accuracy
Objective: To determine the accuracy of police reports (PRs), ambulance reports (ARs), and emergency department records (EDRs) in describing motor vehicle crash (MVC) characteristics when compared with an investigation performed by an experienced crash investigator trained in impact biomechanics. Methods: This was a cross-sectional, observational study. Ninety-one patients transported by ambulance to a university emergency department (ED) directly from the scene of an MVC from August 1997 to April 1998 were enrolled. Potential patients were identified from the ED log and consent was obtained to investigate the crash vehicle. Data describing MVC characteristics were abstracted from the PR, AR, and medical record. Variables of interest included restraint use (RU), air bag deployment (AD), and type of impact (TI). Agreements between the variables and the independent crash investigation were compared using kappa. Interrater reliability was determined using kappa by comparing a random sample of 20 abstracted reports for each data source with the originally abstracted data. Results: Agreement using kappa between the crash investigation and each data source was 0.588 (95% CI = 0.508 to 0.667) for the PR, 0.330 (95% CI = 0.252 to 0.407) for the AR, and 0.492 (95% CI = 0.413 to 0.572) for the EDR. Variable agreement was 0.239 (95% CI = 0.164 to 0.314) for RU, 0.350 (95% CI = 0.268 to 0.432) for AD, and 0.631 (95%= 0.563 to 0.698) for TI. Interrater reliability was excellent (kappa > 0.8) for all data sources. Conclusions: The strength of the agreement between the independent crash investigation and the data sources that were measured by kappa was fair to moderate, indicating inaccuracies. This presents ramifications for researchers and necessitates consideration of the validity and accuracy of crash characteristics contained in these data sources.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75653/1/j.1553-2712.2000.tb02067.x.pd
The Institute of Archaeology & Siegfried H. Horn Museum Newsletter Volume 43.3
Khirbat Safra 2022, Paul Gregor, Robert Bates, Constance Gane, Trisha Broy, and Paul J. Ray, Jr.
Random Surveyhttps://digitalcommons.andrews.edu/iaham-news/1091/thumbnail.jp
Author Correction: Probiotics and prebiotics in intestinal health and disease: from biology to the clinic (Nature Reviews Gastroenterology & Hepatology, (2019), 16, 10, (605-616), 10.1038/s41575-019-0173-3)
© 2019, Springer Nature Limited. In the original article published online, the Competing Interests statement was incorrect and should have stated the following: M.E.S. declares personal fees related to probiotics from the following entities: California Dairy Research Foundation, Clorox, Danone, Danone USA, Dutch Mill, General Mills, JHeimbach, Kelley Drye & Warren, Kellogg, Kerry, Medscape, Nestle, New Chapter, Pepsico, Pfizer, Pharmavite, Probi, Procter & Gamble, Trouw Nutrition, Visalia Dairy Company, Williams Mullen, Winclove Probiotics and Yakult. D.J.M. declares personal fees for consulting for Bayer and Pharmavite. G.R. declares that he helped develop and commercialize probiotic strains GR-1 and RC-14, but has had no financial interest in them for over 10 years. He is Chief Scientific Officer for Seed, a company producing probiotic products. Over the past 3 years, he has consulted on probiotics with Acerus Pharmaceuticals, Altmann, Chr. Hansen, Danone, KGK Science, Kimberly-Clark, Metagenics and Seed. G.R.G. and R.A.R. declare no competing interests. This error has been corrected in the HTML and PDF versions of the article
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Probiotics and prebiotics in intestinal health and disease: from biology to the clinic
Probiotics and prebiotics are microbiota-management tools for improving host health. They target gastrointestinal effects via the gut, although direct application to other sites such as the oral cavity, vaginal tract and skin is being explored. Here, we describe gut-derived effects in humans. In the past decade, research on the gut microbiome has rapidly accumulated and has been accompanied by increased interest in probiotics and prebiotics as a means to modulate the gut microbiota. Given the importance of these approaches for public health, it is timely to reiterate factual and supporting information on their clinical application and use. In this Review, we discuss scientific evidence on probiotics and prebiotics, including mechanistic insights into health effects. Strains of Lactobacillus, Bifidobacterium and Saccharomyces have a long history of safe and effective use as probiotics, but Roseburia spp., Akkermansia spp., Propionibacterium spp. and Faecalibacterium spp. show promise for the future. For prebiotics, glucans and fructans are well proven, and evidence is building on the prebiotic effects of other substances (for example, oligomers of mannose, glucose, xylose, pectin, starches, human milk and polyphenols)
Structures of monomeric and oligomeric forms of the Toxoplasma gondiiperforin-like protein 1
Toxoplasma and Plasmodium are the parasitic agents of toxoplasmosis and malaria, respectively, and use perforin-like proteins (PLPs) to invade host organisms and complete their life cycles. The Toxoplasma gondii PLP1 (TgPLP1) is required for efficient exit from parasitophorous vacuoles in which proliferation occurs. We report structures of the membrane attack complex/perforin (MACPF) and Apicomplexan PLP C-terminal β-pleated sheet (APCβ) domains of TgPLP1. The MACPF domain forms hexameric assemblies, with ring and helix geometries, and the APCβ domain has a novel β-prism fold joined to the MACPF domain by a short linker. Molecular dynamics simulations suggest that the helical MACPF oligomer preserves a biologically important interface, whereas the APCβ domain binds preferentially through a hydrophobic loop to membrane phosphatidylethanolamine, enhanced by the additional presence of inositol phosphate lipids. This mode of membrane binding is supported by site-directed mutagenesis data from a liposome-based assay. Together, these structural and biophysical findings provide insights into the molecular mechanism of membrane targeting by TgPLP1
The Institute of Archaeology & Siegfried H. Horn Museum Newsletter Volume 37.2
Jordan Conference in Amman, Paul J. Ray, Jr.
Jalul 2016, Paul Gregor, Constance E. Gane, Paul J. Ray, Jr., Robert D. Bates, and Randall W. Younker
Random Surveyhttps://digitalcommons.andrews.edu/iaham-news/1066/thumbnail.jp
Time course of functional recovery during the first 3 mo after surgical transection and repair of nerves to the feline soleus and lateral gastrocnemius muscles
Locomotion outcomes after peripheral nerve injury and repair in cats have been described in the literature for the period immediately following the injury (muscle denervation period) and then again for an ensuing period of long-term recovery (at 3 mo and longer) resulting in muscle self-reinnervation. Little is known about the changes in muscle activity and walking mechanics during midrecovery, i.e., the early reinnervation period that takes place between 5 and 10 wk of recovery. Here, we investigated hindlimb mechanics and electromyogram (EMG) activity of ankle extensors in six cats during level and slope walking before and every 2 wk thereafter in a 14-wk period of recovery after the soleus (SO) and lateral gastrocnemius (LG) muscle nerves in one hindlimb were surgically transected and repaired. We found that the continued increase in SO and LG EMG magnitudes and corresponding changes in hindlimb mechanics coincided with the formation of neuromuscular synapses revealed in muscle biopsies. Throughout the recovery period, EMG magnitude of SO and LG during the stance phase and the duration of the stance-related activity were load dependent, similar to those in the intact synergistic medial gastrocnemius and plantaris. These results and the fact that EMG activity of ankle extensors and locomotor mechanics during level and upslope walking recovered 14 wk after nerve transection and repair suggest that loss of the stretch reflex in self-reinnervated muscles may be compensated by the recovered force-dependent feedback in self-reinnervated muscles, by increased central drive, and by increased gain in intermuscular motion-dependent pathways from intact ankle extensors. NEW & NOTEWORTHY This study provides new evidence that the timeline for functional recovery of gait after peripheral nerve injury and repair is consistent with the time required for neuromuscular junctions to form and muscles to reach preoperative tensions. Our findings suggest that a permanent loss of autogenic stretch reflex in self-reinnervated muscles may be compensated by recovered intermuscular force-dependent and oligosynaptic length-dependent feed-back and central drive to regain adequate locomotor output capabilities during level and upslope walking
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