210 research outputs found

    Linking occurrence and changes in local abundance of farmland bird species to landscape composition and land-use changes

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    Changes in agricultural policies have caused dramatic changes in land-use in agricultural landscapes. To investigate whether such changes in land-use relate to temporal changes in bird communities a repeated inventory (1994 and 2004) of farmland birds was made in 212 point-count sites in south-central Sweden.Distinct changes in abundance of several species over the study period were recorded, abundance of the 16 studied species decreased by 23%. The decline was significant for eight species, while two species increased significantly. Persistence and colonisation models suggested similar species-habitat relationships as the snapshot models, i.e. eight of the 12 associations were in line with what could be expected from the snapshot models. Occurrence of nine species was linked to land-use whereas six species displayed links between changes in occurrence and changes in land-use. In line with previous studies positive effects of short rotation coppice and negative effects of autumn-sown crops were found, while set-asides showed fewer effects than expected. In the snapshot models several species showed links to landscape characteristics such as amount of forest (negative for five species) and landscape heterogeneity (positive for six species). The evidence for effects of the landscape variables on persistence/colonisation was more restricted.The results suggest that both land-use changes and the landscape setting may cause local changes in abundance of farmland birds, even for species displaying a general decline in numbers between years, the effects of land-use changes being, however, strongly species specific. (C) 2014 Elsevier B.V. All rights reserved

    SKELETAL KINEMATICS OF THE ANTERIOR CRUCIATE LIGAMENT DEFICIENT KNEE WITH AND WITHOUT FUNCTIONAL BRACES

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    Steinmann traction pins were implanted into the femur and tibia of six subjects having a partial or complete anterior cruciate ligament (ACL) rupture. Patients jumped for maximal horizontal distance and landed onto their deficient limb with the knee braced and unbraced. Tibiofemoral rotations and translations showed a general trend across subjects, i.e. skeletally based curves were similar in shape and amplitude. The tibia displaced anteriorly from footstrike to about peak vertical force onset (Fy). Thereafter the tibia moved posteriorly during flexion. Intra-subject kinematics was very repeatable but differences in anterior tibial translations were small between the brace conditions. This may be due to the invasiveness of this protocol, that landings were onto a deficient limb, or subjects jumped within their own comfort limits which did not maximally stress the ACL. Inter-subject differences were typically much larger

    Аналіз методів компресії даних

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    Background and purpose - There is no consensus on the association between global femoral offset (FO) and outcome after total hip arthroplasty (THA). We assessed the association between FO and patients? reported hip function, quality of life, and abductor muscle strength. Patients and methods - We included 250 patients with unilateral hip osteoarthritis who underwent a THA. Before the operation, the patient?s reported hip function was evaluated with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and quality of life was evaluated with EQ-5D. At 1-year follow-up, the same scores and also hip abductor muscle strength were measured. 222 patients were available for follow-up. These patients were divided into 3 groups according to the postoperative global FO of the operated hip compared to the contralateral hip, as measured on plain radiographs: the decreased FO group (more than 5 mm reduction), the restored FO group (within 5 mm restoration), and the increased FO group (more than 5 mm increment). Results - All 3 groups improved (p < 0.001). The crude results showed that the decreased FO group had a worse WOMAC index, less abductor muscle strength, and more use of walking aids. When we adjusted these results with possible confounding factors, only global FO reduction was statistically significantly associated with reduced abductor muscle strength. The incidence of residual hip pain and analgesics use was similar in the 3 groups. Interpretation - A reduction in global FO of more than 5 mm after THA appears to have a negative association with abductor muscle strength of the operated hip, and should therefore be avoided

    The epidemiology of injuries across the weight-training sports

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    Background: Weight-training sports, including weightlifting, powerlifting, bodybuilding, strongman, Highland Games, and CrossFit, are weight-training sports that have separate divisions for males and females of a variety of ages, competitive standards, and bodyweight classes. These sports may be considered dangerous because of the heavy loads commonly used in training and competition. Objectives: Our objective was to systematically review the injury epidemiology of these weight-training sports, and, where possible, gain some insight into whether this may be affected by age, sex, competitive standard, and bodyweight class. Methods: We performed an electronic search using PubMed, SPORTDiscus, CINAHL, and Embase for injury epidemiology studies involving competitive athletes in these weight-training sports. Eligible studies included peer-reviewed journal articles only, with no limit placed on date or language of publication. We assessed the risk of bias in all studies using an adaption of the musculoskeletal injury review method. Results: Only five of the 20 eligible studies had a risk of bias score ≥75 %, meaning the risk of bias in these five studies was considered low. While 14 of the studies had sample sizes >100 participants, only four studies utilized a prospective design. Bodybuilding had the lowest injury rates (0.12–0.7 injuries per lifter per year; 0.24–1 injury per 1000 h), with strongman (4.5–6.1 injuries per 1000 h) and Highland Games (7.5 injuries per 1000 h) reporting the highest rates. The shoulder, lower back, knee, elbow, and wrist/hand were generally the most commonly injured anatomical locations; strains, tendinitis, and sprains were the most common injury type. Very few significant differences in any of the injury outcomes were observed as a function of age, sex, competitive standard, or bodyweight class. Conclusion: While the majority of the research we reviewed utilized retrospective designs, the weight-training sports appear to have relatively low rates of injury compared with common team sports. Future weight-training sport injury epidemiology research needs to be improved, particularly in terms of the use of prospective designs, diagnosis of injury, and changes in risk exposure

    Rabbit Knee Joint Biomechanics: Motion Analysis and Modeling of Forces during Hopping

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    Although the rabbit hindlimb has been commonly used as an experimental animal model for studies of osteoarthritis, bone growth and fracture healing, the in vivo biomechanics of the rabbit knee joint have not been quantified. The purpose of this study was to investigate the kinematic and kinetic patterns during hopping of the adult rabbit, and to develop a model to estimate the joint contact force distribution between the tibial plateaus. Force platform data and three-dimensional motion analysis using infrared markers mounted on intracortical bone pins were combined to calculate the knee and ankle joint intersegmental forces and moments. A statically determinate model was developed to predict muscle, ligament and tibiofemoral joint contact forces during the stance phase of hopping. Variations in hindlimb kinematics permitted the identification of two landing patterns, that could be distinguished by variations in the magnitude of the external knee abduction moment. During hopping, the prevalence of an external abduction moment led to the prediction of higher joint contact forces passing through the lateral compartment as compared to the medial compartment of the knee joint. These results represent critical data on the in vivo biomechanics of the rabbit knee joint, which allow for comparisons to both other experimental animal models and the human knee, and may provide further insight into the relationships between mechanical loading, osteoarthritis, bone growth, and fracture healing

    The human patellar tendon moment arm assessed in vivo using dual-energy X-ray absorptiometry

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    Accurate assessment of muscle-tendon forces in vivo requires knowledge of the muscle-tendon moment arm. Dual-energy X-ray absorptiometry (DXA) can produce 2D images suitable for visualising both tendon and bone, thereby potentially allowing the moment arm to be measured but there is currently no validated DXA method for this purpose. The aims of this study were (i) to compare in vivo measurements of the patellar tendon moment arm (d) assessed from 2D DXA and magnetic resonance (MR) images and (ii) to compare the reliability of the two methods. Twelve healthy adults (mean±SD: 31.4±9.5yr; 174.0±9.5cm; 76.2±16.6kg) underwent two DXA and two MR scans of the fully extended knee at rest. The tibiofemoral contact point (TFCP) was used as the centre of joint rotation in both techniques, and the d was defined as the perpendicular distance from the patellar tendon axis to the TFCP. The d was consistently longer when assessed via DXA compared to MRI (+3.79±1.25mm or +9.78±3.31%; P<0.001). The test-retest reliability of the DXA [CV=2.13%; ICC=0.94; ratio limits of agreement (RLA)=1.01 (*/÷1.07)] and MR [(CV=2.27%; ICC=0.96; RLA=1.00 (*/÷1.07)] methods was very high and comparable between techniques. Moreover, the RLA between the mean DXA and MRI d values [1.097 (*/÷1.061)] demonstrated very strong agreement between the two methods. In conclusion, highly reproducible d measurements can be determined from DXA imaging with the knee fully extended at rest. This has implications for the calculation of patellar tendon forces in vivo where MR equipment is not available. © 2014 Elsevier Ltd

    Pain control after total knee arthroplasty: a randomized trial comparing local infiltration anesthesia and continuous femoral block

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    Local infiltration analgesia (LIA) is a new multimodal wound infiltration method. It has attracted growing interest in recent years and is widely used all over the world for treating postoperative pain after knee and hip arthroplasty. This method is based on systematic infiltration of a mixture of ropivacaine, a long acting local anesthetic, ketorolac, a cyclooxygenase inhibitor (NSAID), and adrenalin around all structures subject to surgical trauma inknee and hip arthroplasty. Two patient cohorts of 40 patients scheduled for elective total knee arthroplasty (TKA) and 15 patients scheduled for total hip arthroplasty (THA) contributed to the work presented in this thesis. In a randomized trial the efficacy of LIA in TKA with regard to pain at rest and upon movement was compared to femoral block. Both methods result in a high quality pain relief and similar morphine consumption, but fewer patients in the LIA group reported pain of 7/10 on any occasion during the 24 h monitoring period (paper I). In the same patient cohort the maximal total plasma concentration of ropivacaine was below the established toxic threshold for most patients although a few reached potentially toxic concentrations of 1.4-1.7 mg/L. The time to maximal detected plasma concentration was around 4-6 h after release of tourniquet in TKA (paper II). All patients in the THA cohort were subjected to the routine LIA protocol. In these patients both the total and unbound plasma concentration of ropivacaine was determined. The concentration was below the established toxic threshold. As ropivacaine binds to a-1 acid glycoprotein(AAG) we assessed the possibility that increased AAG may decrease the unbound concentration of ropivacaine. A40 % increase in AAG was detected during the first 24 h after surgery, however the fraction of unbound ropivacaine remained the same. There was a trend towards increased C max of ropivacaine with increasing age and decreasing creatinine clearance but the statistical power was too low to draw any conclusion (paper III). Administration of 30mg ketorolac according to the LIA protocol both in TKA and THA resulted in a similar Cmax as previously reported after 10 mg intramuscular ketorolac (paper II, paper IV). Neither age, nor body weight or BMI, nor creatinine clearance, correlates to maximal ketorolac plasma concentration or total exposure to ketorolac (AUC) (paper IV). In conclusion, LIA provides good postoperative analgesia which is similar to femoral block after total knee arthroplasty. The plasma concentration of ropivacaine seems to be below toxic levels in most TKA patients. The unbound plasma concentration of ropivcaine in THA seems to be below the toxic level. The use of ketorolac in LIA may not be safer than other routes of administration, and similar restrictions should be applied in patients at risk of developing side effects

    The multifunctional roles of vegetated strips around and within agricultural fields : A systematic map protocol.

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    Background: Agriculture and agricultural intensification can have significant negative impacts on the environment, including nutrient and pesticide leaching, spreading of pathogens, soil erosion and reduction of ecosystem services provided by terrestrial and aquatic biodiversity. The establishment and management of vegetated strips adjacent to farmed fields (including various field margins, buffer strips and hedgerows) are key mitigation measures for these negative environmental impacts and environmental managers and other stakeholders must often make decisions about how best to design and implement vegetated strips for a variety of different outcomes. However, it may be difficult to obtain relevant, accurate and summarised information on the effects of implementation and management of vegetated strips, even though a vast body of evidence exists on multipurpose vegetated strip interventions within and around fields. To improve the situation, we describe a method for assembling a database of relevant research relating to vegetated strips undertaken in boreo-temperate farming systems (arable, pasture, horticulture, orchards and viticulture). Methods: We will search 13 bibliographic databases, 1 search engine and 37 websites for stakeholder organisations using a predefined and tested search string that focuses on a comprehensive list of vegetated strip synonyms. Non-English language searches in Danish, Finnish, German, Spanish, and Swedish will also be undertaken using a web-based search engine. We will screen search results at title, abstract and full text levels, recording the number of studies deemed non-relevant (with reasons at full text). A systematic map database that displays the meta-data (i.e. descriptive summary information about settings and methods) of relevant studies will be produced following full text assessment. The systematic map database will be displayed as a web-based geographical information system (GIS). The nature and extent of the evidence base will be discussed

    A Holistic Landscape Description Reveals That Landscape Configuration Changes More over Time than Composition: Implications for Landscape Ecology Studies

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    International audienceBackground: Space-for-time substitution—that is, the assumption that spatial variations of a system can explain and predict the effect of temporal variations—is widely used in ecology. However, it is questionable whether it can validly be used to explain changes in biodiversity over time in response to land-cover changes.Hypothesis: ere, we hypothesize that different temporal vs spatial trajectories of landscape composition and configuration may limit space-for-time substitution in landscape ecology. Land-cover conversion changes not just the surface areas given over to particular types of land cover, but also affects isolation, patch size and heterogeneity. This means that a small change in land cover over time may have only minor repercussions on landscape composition but potentially major consequences for landscape configuration.Methods: sing land-cover maps of the Paris region for 1982 and 2003, we made a holistic description of the landscape disentangling landscape composition from configuration. After controlling for spatial variations, we analyzed and compared the amplitudes of changes in landscape composition and configuration over time.Results: For comparable spatial variations, landscape configuration varied more than twice as much as composition over time. Temporal changes in composition and configuration were not always spatially matched.Significance: The fact that landscape composition and configuration do not vary equally in space and time calls into question the use of space-for-time substitution in landscape ecology studies. The instability of landscapes over time appears to be attributable to configurational changes in the main. This may go some way to explaining why the landscape variables that account for changes over time in biodiversity are not the same ones that account for the spatial distribution of biodiversity

    Velocity change estimation by subjective measures over a wide-load spectrum in squat and bench press

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    This study compared whether the perception of effort measured on a repetition-by-repetition basis during continuous sets to failure are different between squat (SQ) and bench press (BP). After determining the 1RM value in both SQ and BP, eighteen participants (28.2 ± 5 years, 50% females) performed seven sets to failure per exercise, separated by 24-h to 48-h, alternating SQ and BP, using the following relative loadranges 3090%. The mean accelerative velocity (MAV) and Rating of Perceived Exertion (RPE) using the OMNI-RES (0-10) scale were measured for every repetition of each set. The ability of the OMNI-RES (0-10) scale to identify velocity changes during continuous sets to volitional failure and to distinguish loading zones divided into 10% slots, from 30 to 100% of 1RM was confirmed for both SQ and BP. The RPE values measured at (i) the first repetition; (ii) the repetition where MAV peaks; (ii) the repetition where MAV drops by ≤10% compared the maximum and (iv) the last repetition, showed no differences (p>0.05, d<0.2) between exercises. In conclusion, the same RPE scores can be applied to both exercises, for either estimating the relative load and monitoring changes in MAV during continuous sets to failure
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