568 research outputs found

    Breeding Season Survival and Nesting of Northern Bobwhite on Native Prairie Versus Traditionally Managed Conservation Areas in Southwestern Missouri

    Get PDF
    Northern bobwhite (Colinus virginianus) management on Missouri Conservation Area lands has traditionally focused on providing an interspersion of grass, crop, old field and woody cover to enhance edge habitat often juxtaposed with disked idle areas and food plots. This traditional approach, or the Intensive Management Model (IMM), is often implemented with the goal of providing all essential habitat components within a 40-acre area. While this model can produce useable quail habitat in agriculture-dominated landscapes it may not be the most effective or efficient approach to producing quail in grassland-dominated landscapes found in southwest Missouri. Conservation area mangers for the Missouri Department of Conservation (MDC) have historically implemented IMM in these grass-dominated landscapes; however in a few areas managers have begun using historical ecological processes, such as fire with grazing, or the Extensive Management Model (EMM) in conjunction with IMM or as the primary means for producing the patchy habitat mosaic preferred by bobwhite quail. In 2015, MDC began a 5 year study radio marking 60 individuals per area on 4 areas (2 IMM and 2 EMM) to compare the utility of these two models and the habitat conditions they create on breeding season vital rates (survival and production). Over the first 2 years of this study, EMM areas had higher breeding season survival (0.414 compared to 0.275) and nesting success (0.437 compared to 0.355) relative to IMM areas. Additionally, covey break-up and nest initiation were in general earlier, and clutch sizes were larger on areas managed with EMM than on areas managed with IMM

    Home Range and Space Use of Northern Bobwhite Under Two Different Management Models in Southwestern Missouri

    Get PDF
    Northern bobwhite (Colinus virginianus; hereafter, bobwhite) management in Missouri, USA has traditionally been focused on providing an interspersion of grass, crop, old field, and woody cover juxtaposed to disked idle areas and food plots to maintain bobwhite populations. This traditional model is implemented with the goal of providing all essential habitat components within 40-acre blocks throughout a larger area used by a population. While this model can produce usable bobwhite space in agriculture-dominated landscapes, it may not be the most effective or efficient approach to producing and maintaining bobwhite in grassland-dominated landscapes. In southwestern Missouri native tallgrass prairie conservation areas are managed primarily with historical ecological processes, such as fire and grazing, to produce the desired patchy habitat mosaic. Additionally, it has been on these native tallgrass prairie conservation areas that managers have seen the most stable and productive bobwhite populations. Over a 5-year period (2014–2018) we quantified movements of northern bobwhite on 3 traditionally managed areas (n = 185) and on 3 managed native tallgrass prairie conservation areas (n = 211) to determine whether home range sizes and space use differed between these two management models. We used the 6-month (Apr–Sep) breeding period to determine core area, home range, mean movement rate, and maximum distance moved. Overall (pooled) home ranges of bobwhite did not differ significantly between traditional and grassland managed areas; however, there were significant yearly differences between management models and study areas. Males generally had larger home range sizes and had higher movement rates than females. For the 5 years of the study few birds made long-distance movements (\u3e1.6 km; 3%), and all remained relatively close to capture locations in winter (Feb–Mar). For both traditional and grassland managed areas, bobwhite selected for areas that had disturbance (fire and grazing) in the last 2 years and for the native grassland vegetation type. These findings suggest that areas managed under the grassland management model provide preferred habitat for bobwhite and could result in significant improvement in habitat quality for tallgrass prairie wildlife

    Average of trial peaks versus peak of average profile : impact on change of direction biomechanics

    Get PDF
    The aims of this study were twofold: firstly, to compare lower limb kinematic and kinetic variables during a sprint and 90° cutting task between two averaging methods of obtaining discrete data (peak of average profile vs. average of individual trial peaks); secondly, to determine the effect of averaging methods on participant ranking of each variable within a group. Twenty-two participants, from multiple sports, performed a 90° cut, whereby lower limb kinematics and kinetics were assessed via 3D motion and ground reaction force (GRF) analysis. Six of the eight dependent variables (vertical and horizontal GRF; hip flexor, knee flexor, and knee abduction moments, and knee abduction angle) were significantly greater (p ≤ 0.001, g = 0.10-0.37, 2.74-10.40%) when expressed as an average of trial peaks compared to peak of average profiles. Trivial (g ≤ 0.04) and minimal differences (≤ 0.94%) were observed in peak hip and knee flexion angle between averaging methods. Very strong correlations (ρ ≥ 0.901, p <0.001) were observed for rankings of participants between averaging methods for all variables. Practitioners and researchers should obtain discrete data based on the average of trial peaks because it is not influenced by misalignments and variations in trial peak locations, in contrast to the peak from average profile

    Retinal nerve fiber layer abnormalities in Alzheimer's disease

    Full text link
    Retinal nerve fiber layer (RNFL) photographs from 26 patients with Alzheimer's disease and 23 normal, age-matched, control subjects were reviewed for quality and abnormalities by two observers. A higher proportion of Alzheimer's patients showed RNFL abnormalities when compared to control subjects. There was some disagreement between the two observers regarding quality and frequency of abnormalities, reflecting suboptimal quality of the photographs obtained in patients with advanced Alzheimer's disease. Although these findings add to the clinical and histopathological evidence that ganglion cell degeneration occurs in Alzheimer's disease, the difficulty in obtaining and evaluating retinal nerve fiber layer photographs, especially in advanced cases, may limit the clinical usefulness of retinal nerve fiber layer analysis in such patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73257/1/j.1600-0420.1996.tb00090.x.pd

    RADIOCARBON AND STABLE ISOTOPE EVIDENCE OF DIETARY CHANGE FROM THE MESOLITHIC TO THE MIDDLE AGES IN THE IRON GATES: NEW RESULTS FROM LEPENSKI VIR

    Get PDF
    This is the published version, also available here: https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/4269.A previous radiocarbon dating and stable isotope study of directly associated ungulate and human bone samples from Late Mesolithic burials at Schela Cladovei in Romania established that there is a freshwater reservoir effect of approximately 500 yr in the Iron Gates reach of the Danube River valley in southeast Europe. Using the d15N values as an indicator of the percentage of freshwater protein in the human diet, the 14C data for 24 skeletons from the site of Lepenski Vir were corrected for this reservoir effect. The results of the paired 14C and stable isotope measurements provide evidence of substantial dietary change over the period from about 9000 BP to about 300 BP. The data from the Early Mesolithic to the Chalcolithic are consistent with a 2-component dietary system, where the linear plot of isotopic values reflects mixing between the 2 end-members to differing degrees. Typically, the individuals of Mesolithic age have much heavier d15N signals and slightly heavier d13C, while individuals of Early Neolithic and Chalcolithic age have lighter d15N and d13C values. Contrary to our earlier suggestion, there is no evidence of a substantial population that had a transitional diet midway between those that were characteristic of the Mesolithic and Neolithic. However, several individuals with Final Mesolithic 14C ages show d15N and d13C values that are similar to the Neolithic dietary pattern. Provisionally, these are interpreted either as incomers who originated in early farming communities outside the Iron Gates region or as indigenous individuals representing the earliest Neolithic of the Iron Gates. The results from Roman and Medieval age burials show a deviation from the linear function, suggesting the presence of a new major dietary component containing isotopically heavier carbon. This is interpreted as a consequence of the introduction of millet into the human food chain

    Northern Bobwhite Demographics and Resource Selection Are Explained by Prescribed Fire with Grazing and Woody Cover in Southwest Missouri

    Get PDF
    Understanding the effects of landscape management on northern bobwhite (Colinus virginianus; hereafter, bobwhite) population growth requires information about seasonal- and stage-specific demographic parameters linked across the annual cycle. We review results to date from 3 years (2016–2018) of an intensive field study evaluating drivers of bobwhite population dynamics and resource selection during the breeding and non-breeding season in southwest Missouri, USA using data from adult and juvenile bobwhite fitted with radio-transmitters. Land cover of our study sites ranged from large blocks of native grasslands maintained with prescribed fire and grazing to more traditional management resulting in small patches of grasslands interspersed with food plots, disked idle areas, and woody cover. During the breeding season, relative probability of selection by broods increased in relation to proportion of native grass managed by grazing and burning and proportion of cropland. Brood survival was also greatest on native grasslands burned and grazed within the past 2 growing seasons. During the fall and winter, relative probability of selection by adults increased as woody edge density increased. Fall and winter survival increased as distance from trees increased and decreased as distance to shrubs increased. Our integrated population model indicated that the number of young hatched per female and adult breeding season survival were greatest on sites with the most native grassland managed by prescribed fire with grazing. However, non-breeding season survival was greater on sites with more agriculture or food plots and woody cover. Abundance declined across all sites from 2016 to 2019. Our work suggests that native grasslands managed by prescribed fire with grazing can provide quail habitat superior to traditional management that strived for a mixture of agriculture, woody cover, and grassland. The combination of conservation grazing and fire in native grasslands interspersed with shrubs may provide the greatest chance for bobwhite populations to persist in southwest Missouri and similar landscapes

    The Basics of Water Waves Theory for Analogue Gravity

    Full text link
    This chapter gives an introduction to the connection between the physics of water waves and analogue gravity. Only a basic knowledge of fluid mechanics is assumed as a prerequisite.Comment: 36 pages. Lecture Notes for the IX SIGRAV School on "Analogue Gravity", Como (Italy), May 201

    Quantum fluctuations can promote or inhibit glass formation

    Full text link
    The very nature of glass is somewhat mysterious: while relaxation times in glasses are of sufficient magnitude that large-scale motion on the atomic level is essentially as slow as it is in the crystalline state, the structure of glass appears barely different than that of the liquid that produced it. Quantum mechanical systems ranging from electron liquids to superfluid helium appear to form glasses, but as yet no unifying framework exists connecting classical and quantum regimes of vitrification. Here we develop new insights from theory and simulation into the quantum glass transition that surprisingly reveal distinct regions where quantum fluctuations can either promote or inhibit glass formation.Comment: Accepted for publication in Nature Physics. 22 pages, 3 figures, 1 Tabl

    Quantifying Selective Reporting and the Proteus Phenomenon for Multiple Datasets with Similar Bias

    Get PDF
    Meta-analyses play an important role in synthesizing evidence from diverse studies and datasets that address similar questions. A major obstacle for meta-analyses arises from biases in reporting. In particular, it is speculated that findings which do not achieve formal statistical significance are less likely reported than statistically significant findings. Moreover, the patterns of bias can be complex and may also depend on the timing of the research results and their relationship with previously published work. In this paper, we present an approach that is specifically designed to analyze large-scale datasets on published results. Such datasets are currently emerging in diverse research fields, particularly in molecular medicine. We use our approach to investigate a dataset on Alzheimer's disease (AD) that covers 1167 results from case-control studies on 102 genetic markers. We observe that initial studies on a genetic marker tend to be substantially more biased than subsequent replications. The chances for initial, statistically non-significant results to be published are estimated to be about 44% (95% CI, 32% to 63%) relative to statistically significant results, while statistically non-significant replications have almost the same chance to be published as statistically significant replications (84%; 95% CI, 66% to 107%). Early replications tend to be biased against initial findings, an observation previously termed Proteus phenomenon: The chances for non-significant studies going in the same direction as the initial result are estimated to be lower than the chances for non-significant studies opposing the initial result (73%; 95% CI, 55% to 96%). Such dynamic patters in bias are difficult to capture by conventional methods, where typically simple publication bias is assumed to operate. Our approach captures and corrects for complex dynamic patterns of bias, and thereby helps generating conclusions from published results that are more robust against the presence of different coexisting types of selective reporting

    GaMin’11 – an International Inter-laboratory Comparison for Geochemical CO2 - Saline Fluid - Mineral Interaction Experiments

    Get PDF
    Due to the strong interest in geochemical CO2-fluid-rock interaction in the context of geological storage of CO2 a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in composition of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies
    corecore