150 research outputs found

    Back stress and assistance exercises in extreme weightlifting

    Get PDF
    The purpose or this study was to test the suitability or selected assistance exercises to strengthen the low back for the Olympic lilts in elite weightlifters. Four subjects were filmed by a five-camera Motion Analysis system operating at 120Hz. The subjects completed both or the Olympic lifts (Snatch and Clean) at a near one repetition maximum and four assistance exercises (Bent-over Row, Clean Pull Deadlift, Romanian Deadlift, and Good Morning) at an intensity typically performed at a routine training session. Peak moments, compressive and shear forces about the L5/S1 intervertebral joint were calculated via a top-down inverse dynamics model. Comparisons were made between the lifts using a one way ANOVA with repeated measures and post-hoc differences between the means were calculated via Least Squared Differences. Significant differences (

    Brangus cows have ovarian reserve parameters more like Brahman than Angus cows

    Get PDF
    Bos indicus females have more surface antral follicles than Bos taurus females; however, histological studies demonstrated no difference in total number of primordial follicles between these two biological types of cattle. Primordial follicle density in the ovary was less in Nelore ovaries compared to Angus ovaries, but no studies have examined the primordial follicle density in Bos indicus cross-bred females. It, therefore, was hypothesized that primordial follicle density in the ovary would decrease as percentage Bos indicus increased. Ovaries were collected from cross-bred Angus (n=32, no Bos indicus influence), Brangus (n=15), or Brahman (n=9) cows and prepared for histological evaluation. There was no difference in total number of primordial follicles per ovary between breeds (P \u3e 0.10). When numbers of primordial follicles were expressed on a per gram of ovarian tissue basis, there were fewer primordial follicles per gram of ovarian tissue in Brangus and Brahman cows than in Angus cows (P \u3c 0.05). Brangus cows did not differ from Brahman cows in primordial follicle density (P \u3e 0.10). Differences in primordial follicle density could indicate differences in capacity of ovarian stroma to produce factors necessary for oogonial proliferation and primordial follicle formation among breeds. Identifying these factors could improve the aprroach for culturing pre-antral follicles of cattle. Furthermore, these results explain why ultrasonographic antral follicle counts may need to be adjusted to a greater threshold to predict size of the ovarian reserve and determine ovarian reserve related reproductive traits in Bos indicus females

    The tetanic depression in fast motor units of mammalian skeletal muscle can be evoked by lengthening of one initial interpulse interval

    Get PDF
    A lower than expected tetanic force (the tetanic depression) is regularly observed in fast motor units (MUs) when a higher stimulation frequency immediately follows a lower one. The aim of the present study was to determine whether prolongation of only the first interpulse interval (IPI) resulted in tetanic depression. The experiments were carried out on fast MUs of the medial gastrocnemius muscle in cats and rats. The tetanic depression was measured in each case as the force decrease of a tetanus with one IPI prolonged in relation to the tetanic force at the respective constant stimulation frequency. Force depression was observed in all cases studied and was considerably greater in cats. For cats, the mean values of force depression amounted to 28.64% for FR and 10.86% for FF MUs whereas for rats 9.30 and 7.21% for FR and FF motor units, respectively. Since the phenomenon of tetanic depression in mammalian muscle is commonly observed even after a change in only the initial interpulse interval within a stimulation pattern, it can effectively influence processes of force regulation during voluntary activity of a muscle, when motoneurones progressively increase the firing rate

    TOI-2015b: A Warm Neptune with Transit Timing Variations Orbiting an Active mid M Dwarf

    Full text link
    We report the discovery of a close-in (Porb=3.349 daysP_{\mathrm{orb}} = 3.349\:\mathrm{days}) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby (d=47.3 pcd=47.3\:\mathrm{pc}) active M4 star, TOI-2015. We characterize the planet's properties using TESS photometry, precise near-infrared radial velocities (RV) with the Habitable-zone Planet Finder (HP) Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius Rp = 3.37−0.20+0.15 R⊕R_p~=~3.37_{-0.20}^{+0.15} \:\mathrm{R_\oplus}, mass mp = 16.4−4.1+4.1 M⊕m_p~=~16.4_{-4.1}^{+4.1}\:\mathrm{M_\oplus}, and density ρp = 2.32−0.37+0.38 gcm−3\rho_p~=~2.32_{-0.37}^{+0.38} \:\mathrm{g cm^{-3}} for TOI-2015b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of Prot = 8.7± 0.9 daysP_{\mathrm{rot}}~=~8.7 \pm~0.9~\mathrm{days} and associated rotation-based age estimate of 1.1 ± 0.1 Gyr1.1~\pm~0.1\:\mathrm{Gyr}. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super period Psup ≈ 430 daysP_{\mathrm{sup}}~\approx~430\:\mathrm{days} and amplitude ∌\sim100 minutes100\:\mathrm{minutes}. After considering multiple likely period ratio models, we show an outer planet candidate near a 2:1 resonance can explain the observed TTVs while offering a dynamically stable solution. However, other possible two-planet solutions -- including 3:2 and 4:3 resonance -- cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of mb = 13.3−4.5+4.7 M⊕m_b~=~13.3_{-4.5}^{+4.7}\:\mathrm{M_\oplus} for TOI-2015b and mc = 6.8−2.3+3.5 M⊕m_c~=~6.8_{-2.3}^{+3.5}\:\mathrm{M_\oplus} for the outer candidate. Additional transit and RV observations will be beneficial to explicitly identify the resonance and further characterize the properties of the system.Comment: 28 pages, 15 figures, 6 tables. As submitted to AAS Journal

    Economic Returns to Investment in AIDS Treatment in Low and Middle Income Countries

    Get PDF
    Since the early 2000s, aid organizations and developing country governments have invested heavily in AIDS treatment. By 2010, more than five million people began receiving antiretroviral therapy (ART) – yet each year, 2.7 million people are becoming newly infected and another two million are dying without ever having received treatment. As the need for treatment grows without commensurate increase in the amount of available resources, it is critical to assess the health and economic gains being realized from increasingly large investments in ART. This study estimates total program costs and compares them with selected economic benefits of ART, for the current cohort of patients whose treatment is cofinanced by the Global Fund to Fight AIDS, Tuberculosis and Malaria. At end 2011, 3.5 million patients in low and middle income countries will be receiving ART through treatment programs cofinanced by the Global Fund. Using 2009 ART prices and program costs, we estimate that the discounted resource needs required for maintaining this cohort are 14.2billionfortheperiod2011–2020.Thisinvestmentisexpectedtosave18.5millionlife−yearsandreturn14.2 billion for the period 2011–2020. This investment is expected to save 18.5 million life-years and return 12 to $34 billion through increased labor productivity, averted orphan care, and deferred medical treatment for opportunistic infections and end-of-life care. Under alternative assumptions regarding the labor productivity effects of HIV infection, AIDS disease, and ART, the monetary benefits range from 81 percent to 287 percent of program costs over the same period. These results suggest that, in addition to the large health gains generated, the economic benefits of treatment will substantially offset, and likely exceed, program costs within 10 years of investment

    TOI-3984 A b and TOI-5293 A b: two temperate gas giants transiting mid-M dwarfs in wide binary systems

    Full text link
    We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A (J=11.93J=11.93) is an M4 dwarf hosting a short-period (4.353326±0.0000054.353326 \pm 0.000005 days) gas giant (Mp=0.14±0.03 MJM_p=0.14\pm0.03~\mathrm{M_{J}} and Rp=0.71±0.02 RJR_p=0.71\pm0.02~\mathrm{R_{J}}) with a wide separation white dwarf companion. TOI-5293 A (J=12.47J=12.47) is an M3 dwarf hosting a short-period (2.930289±0.0000042.930289 \pm 0.000004 days) gas giant (Mp=0.54±0.07 MJM_p=0.54\pm0.07~\mathrm{M_{J}} and Rp=1.06±0.04 RJR_p=1.06\pm0.04~\mathrm{R_{J}}) with a wide separation M dwarf companion. We characterize both systems using a combination of ground-based and space-based photometry, speckle imaging, and high-precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs. TOI-3984 A b (Teq=563±15T_{eq}=563\pm15 K and TSM=138−27+29\mathrm{TSM}=138_{-27}^{+29}) and TOI-5293 A b (Teq=675−30+42T_{eq}=675_{-30}^{+42} K and TSM=92±14\mathrm{TSM}=92\pm14) are two of the coolest gas giants among the population of hot Jupiter-sized gas planets orbiting M dwarfs and are favorable targets for atmospheric characterization of temperate gas giants and three-dimensional obliquity measurements to probe system architecture and migration scenarios.Comment: Submitted to AJ, 42 pages, 14 figures. arXiv admin note: substantial text overlap with arXiv:2201.0996

    The effect of local anaesthetic wound infiltration on chronic pain after lower limb joint replacement: A protocol for a double-blind randomised controlled trial

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>For the majority of patients with osteoarthritis (OA), joint replacement is a successful intervention for relieving chronic joint pain. However, between 10-30% of patients continue to experience chronic pain after joint replacement. Evidence suggests that a risk factor for chronic pain after joint replacement is the severity of acute post-operative pain. The aim of this randomised controlled trial (RCT) is to determine if intra-operative local anaesthethic wound infiltration additional to a standard anaethesia regimen can reduce the severity of joint pain at 12-months after total knee replacement (TKR) and total hip replacement (THR) for OA.</p> <p>Methods</p> <p>300 TKR patients and 300 THR patients are being recruited into this single-centre double-blind RCT. Participants are recruited before surgery and randomised to either the standard care group or the intervention group. Participants and outcome assessors are blind to treatment allocation throughout the study. The intervention consists of an intra-operative local anaesthetic wound infiltration, consisting of 60 mls of 0.25% bupivacaine with 1 in 200,000 adrenaline. Participants are assessed on the first 5 days post-operative, and then at 3-months, 6-months and 12-months. The primary outcome is the WOMAC Pain Scale, a validated measure of joint pain at 12-months. Secondary outcomes include pain severity during the in-patient stay, post-operative nausea and vomiting, satisfaction with pain relief, length of hospital stay, joint pain and disability, pain sensitivity, complications and cost-effectiveness. A nested qualitative study within the RCT will examine the acceptability and feasibility of the intervention for both patients and healthcare professionals.</p> <p>Discussion</p> <p>Large-scale RCTs assessing the effectiveness of a surgical intervention are uncommon, particulary in orthopaedics. The results from this trial will inform evidence-based recommendations for both short-term and long-term pain management after lower limb joint replacement. If a local anaesthetic wound infiltration is found to be an effective and cost-effective intervention, implementation into clinical practice could improve long-term pain outcomes for patients undergoing lower limb joint replacement.</p> <p>Trial registration</p> <p>Current Controlled Trials <a href="http://www.controlled-trials.com/ISRCTN96095682">ISRCTN96095682</a></p

    Diurnal timing of nonmigratory movement by birds: the importance of foraging spatial scales

    Get PDF
    Timing of activity can reveal an organism's efforts to optimize foraging either by minimizing energy loss through passive movement or by maximizing energetic gain through foraging. Here, we assess whether signals of either of these strategies are detectable in the timing of activity of daily, local movements by birds. We compare the similarities of timing of movement activity among species using six temporal variables: start of activity relative to sunrise, end of activity relative to sunset, relative speed at midday, number of movement bouts, bout duration and proportion of active daytime hours. We test for the influence of flight mode and foraging habitat on the timing of movement activity across avian guilds. We used 64 570 days of GPS movement data collected between 2002 and 2019 for local (non‐migratory) movements of 991 birds from 49 species, representing 14 orders. Dissimilarity among daily activity patterns was best explained by flight mode. Terrestrial soaring birds began activity later and stopped activity earlier than pelagic soaring or flapping birds. Broad‐scale foraging habitat explained less of the clustering patterns because of divergent timing of active periods of pelagic surface and diving foragers. Among pelagic birds, surface foragers were active throughout all 24 hrs of the day while diving foragers matched their active hours more closely to daylight hours. Pelagic surface foragers also had the greatest daily foraging distances, which was consistent with their daytime activity patterns. This study demonstrates that flight mode and foraging habitat influence temporal patterns of daily movement activity of birds.We thank the Nature Conservancy, the Bailey Wildlife Foundation, the Bluestone Foundation, the Ocean View Foundation, Biodiversity Research Institute, the Maine Outdoor Heritage Fund, the Davis Conservation Foundation and The U.S. Department of Energy (DE‐EE0005362), and the Darwin Initiative (19-026), EDP S.A. ‘Fundação para a Biodiversidade’ and the Portuguese Foundation for Science and Technology (FCT) (DL57/2019/CP 1440/CT 0021), Enterprise St Helena (ESH), Friends of National Zoo Conservation Research Grant Program and Conservation Nation, ConocoPhillips Global Signature Program, Maryland Department of Natural Resources, Cellular Tracking Technologies and Hawk Mountain Sanctuary for providing funding and in-kind support for the GPS data used in our analyses
    • 

    corecore