254 research outputs found
Status of In-Service Audio-Visual Education in Nebraska
The main purpose of this study was to determine the present status of in-service audio-visual education in Nebraska. This involved three minor problems: 1. the amount and nature of pre-service training in the use of audio-visual materials; 2. the content and extent of the in-service audio-visual training program; and 3. the reaction of administrators to what more could have been accomplished in pre-service audio-visual programs
Recolonizing wolves and mesopredator suppression of coyotes:impacts on pronghorn population dynamics
Food web theory predicts that the loss of large carnivores may contribute toelevated predation rates and, hence, declining prey populations, through the process ofmesopredator release. However, opportunities to test predictions of the mesopredator releasehypothesis are rare, and the extent to which changes in predation rates inïŹuence preypopulation dynamics may not be clear due to a lack of demographic information on the preypopulation of interest. We utilized spatial and seasonal heterogeneity in wolf distribution andabundance to evaluate whether mesopredator release of coyotes (Canis latrans), resulting fromthe extirpation of wolves (Canis lupus) throughout much of the United States, contributes tohigh rates of neonatal mortality in ungulates. To test this hypothesis, we contrasted causes ofmortality and survival rates of pronghorn (Antilocapra americana) neonates captured at wolf-free and wolf-abundant sites in western Wyoming, USA, between 2002 and 2004. We thenused these data to parameterize stochastic population models to heuristically assess the impactof wolves on pronghorn population dynamics due to changes in neonatal survival. Coyotepredation was the primary cause of mortality at all sites, but mortality due to coyotes was 34%lower in areas utilized by wolves (P , 0.001). Based on simulation modeling, the realizedpopulation growth rate was 0.92 based on fawn survival in the absence of wolves, and 1.06 atsites utilized by wolves. Thus, wolf restoration is predicted to shift the trajectory of thepronghorn population from a declining to an increasing trend. Our results suggest thatreintroductions of large carnivores may inïŹuence biodiversity through effects on preypopulations mediated by mesopredator suppression. In addition, our approach, whichcombines empirical data on the population of interest with information from other datasources, demonstrates the utility of using simulation modeling to more fully evaluateecological theories by moving beyond estimating changes in vital rates to analyses ofpopulation-level impacts
Predicting breastfeeding in women living in areas of economic hardship : explanatory role of the theory of planned behaviour
This study employed the theory of planned behaviour (TPB) and additional variables (descriptive norm, moral norm, self-identity) to investigate the factors underlying breastfeeding intention and subsequent breastfeeding at four time points (during hospital stay, at hospital discharge, 10 days postpartum and 6 weeks postpartum) in a sample of women selected from defined areas of economic hardship (N = 248). A model containing the TPB, additional variables and demographic factors provided a good prediction of both intention (R-2 = 0.72; attitude, perceived behavioural control, moral norm and self-identity significant predictors) and behaviour - breastfeeding at birth (88.6% correctly classified; household deprivation, intention, attitude significant), at discharge from hospital (87.3% correctly classified; intention, attitude significant), 10 days after discharge (83.1% correctly classified; education, intention, attitude, descriptive norm significant) and 6 weeks after discharge (78.0% correctly classified; age, household deprivation, ethnicity, moral norm significant). Implications for interventions are discussed, such as the potential usefulness of targeting descriptive norms, moral norms and perceived behavioural control (PBC) when attempting to increase breastfeeding uptake
Keeping It Classy: Classification of Live Fish and Ghost PIT Tags Detected With a Mobile PIT Tag Interrogation System Using an Innovative Analytical Approach
The ability of passive integrated transponder (PIT) tag data to improve demographic parameter estimates has led to the rapid advancement of PIT tag systems. However, ghost tags create uncertainty about detected tag status (i.e., live fish or ghost tag) when using mobile interrogation systems. We developed a method to differentiate between live fish and ghost tags using a random forest classification model with a novel data input structure based on known fate PIT tag detections in the San Juan River (New Mexico, Colorado, and Utah, USA). We used our model to classify detected tags with an overall error rate of 6.8% (1.6% ghost tags error rate and 21.8% live fish error rate). The important variables for classification were related to distance moved and response to monsoonal flood flows; however, habitat variables did not appear to influence model accuracy. Our results and approach allow the use of mobile detection data with confidence and allow for greater accuracy in movement, distribution, and habitat use studies, potentially helping identify influential management actions that would improve our ability to conserve and recover endangered fish
Use of Subsistence-Harvested Whale Carcasses by Polar Bears in the Southern Beaufort Sea
The availability of a food subsidy has the potential to influence the condition, behavior, fitness, and population dynamics of a species. Since the early 2000s, monitoring efforts along the coast of northern Alaska have indicated a higher proportion of polar bears (Ursus maritimus) of the southern Beaufort Sea (SB) subpopulation coming onshore to feed on subsistence-harvested bowhead whale (Balaena mysticetus) carcasses during the fall and early winter seasons. Concurrently, Indigenous communities annually hunt bowhead whale and deposit the unused remains at localized âbone piles,â creating the potential for human-bear interactions. Our objective was to determine the annual number of polar bears feeding at the bone pile near Kaktovik, Alaska. Using a hair snag surrounding the bone pile, we collected hair samples to identify individual bears via microsatellite genotypes during 2011 â 14. We used capture-mark-recapture data in the POPAN open-population model to estimate the number of bears visiting the bone pile. We estimated that as many as 72 (SE = 9) and 76 (SE = 10) male and female polar bears, respectively, used the bone pile located at Kaktovik, Alaska, in 2012, which represents approximately 16% of the SB polar bear subpopulation. It will be important to monitor the number of bears using the bone pile and subsequent human-bear interactions and conflicts along the northern coast of Alaska, if sea ice continues to recede.Lâexistence de subventions alimentaires a la possibilitĂ© dâinfluencer lâĂ©tat, le comportement, la condition physique et la dynamique de la population dâune espĂšce. Depuis le dĂ©but des annĂ©es 2000, les efforts de surveillance dĂ©ployĂ©s sur la cĂŽte nord de lâAlaska ont laissĂ© entrevoir une plus grande proportion dâours polaires (Ursus maritimus) de la sous-population du sud de la mer de Beaufort venant sur le littoral pour manger les carcasses des baleines borĂ©ales (Balaena mysticetus) pĂȘchĂ©es Ă des fins de subsistance pendant les saisons de lâautomne et du dĂ©but de lâhiver. En mĂȘme temps, les collectivitĂ©s autochtones chassent les baleines borĂ©ales tous les ans et dĂ©posent leurs restes dans des « tas dâossements », ce qui crĂ©e la possibilitĂ© dâinteractions entre les humains et les ours. Notre objectif consistait Ă dĂ©terminer le nombre annuel dâours polaires qui sâalimentent au tas dâossements situĂ© prĂšs de Kaktovik, en Alaska. De 2011 Ă 2014, Ă lâaide dâun piĂšge Ă poils placĂ© prĂšs du tas dâossements, nous avons recueilli des Ă©chantillons de poils afin dâidentifier les ours individuels au moyen de gĂ©notypes microsatellites. Nous avons employĂ© les donnĂ©es de capture-marquage-recapture du modĂšle de population ouverte POPAN pour estimer le nombre dâours se rendant au tas dâossements. Nous avons estimĂ© que jusquâĂ 72 (ET = 9) et 76 (ET = 10) ours polaires mĂąles et femelles, respectivement, ont utilisĂ© le tas dâossements de Kaktovik, en Alaska, en 2012, ce qui reprĂ©sente environ 16 % de la sous-population dâours polaires du sud de la mer de Beaufort. Il sera important de surveiller le nombre dâours qui utilisent le tas dâossements de mĂȘme que les interactions et les conflits entre les humains et les ours qui sâensuivront sur la cĂŽte nord de lâAlaska si la glace de mer continue de reculer
A meta-BACI approach forevaluating management intervention on chronic wasting disease in mule deer
Advances in acquiring and analyzing the spatial attributes of data have greatlyenhanced the potential utility of wildlife disease surveillance data for addressing problems ofecological or economic importance. We present an approach for using wildlife diseasesurveillance data to identify areas for (or of ) intervention, to spatially delineate pairedtreatment and control areas, and then to analyze these nonrandomly selected sites in a meta-analysis framework via beforeâafterâcontrolâimpact (BACI) estimates of effect size. We applythese methods to evaluate the effectiveness of attempts to reduce chronic wasting disease(CWD) prevalence through intensive localized culling of mule deer (Odocoileus hemionus)innorth-central Colorado, USA. Areas where surveillance data revealed high prevalence or caseclusters were targeted by state wildlife management agency personnel for focal scale (onaverage ,17 km2) culling, primarily via agency sharpshooters. Each area of sustained cullingthat we could also identify as unique by cluster analysis was considered a potential treatmentarea. Treatment areas, along with spatially paired control areas that we constructed post hocin a case-control design (collectively called ââmanagement evaluation sitesââ), were thendelineated using home range estimators. Using meta-BACI analysis of CWD prevalence datafor all management evaluation sites, the mean effect size (change of prevalence on treatmentareas minus change in prevalence on their paired control areas) was 0.03 (SE ÂŒ 0.03); meaneffect size on treatment areas was not greater than on paired control areas. Excluding cullsamples from prevalence estimates or allowing for an equal or greater two-year lag in systemresponses to management did not change this outcome. We concluded that managementbeneïŹts were not evident, although whether this represented true ineffectiveness or was a resultof lack of data or insufïŹcient duration of treatment could not be discerned. Based on ourobservations, we offer recommendations for designing a management experiment with 80%power to detect a 0.10 drop in prevalence over a 6â12-year period
Fire resistance characteristics of selected multilayer fabric assemblies in varying air conditions
The major purpose of this study was to investigate the burning characteristics of multiple layer fabric assemblies burned in varying air conditions. The fire resistance characteristics of three layer fabric assemblies, with and without air space between layers, was tested in conditions of moving and quiescent air. A fire resistance tester specially designed to incorporate moving air into the testing cabinet was used. The testing procedure followed was #34-1969 of the American Association of Textile Chemists and Colorists. The experimental fabrics in all outer garment layers were of 100% cotton or 80/20 cotton/polyester and untreated or treated with THPOH-NH3 or THPOH-Amide. The second layer of the assembly consisted of fabrics of either 100% cotton, 100% nylon, or 65/35 polyester/cotton. A 100% cotton knit or 100% nylon knit comprised the third layer. Data were collected by measuring afterflame time (in seconds), afterglow time (in seconds), and fabric damage (in inches) of each assembly, and analyzed based upon a randomized factorial design. An analysis of variance was employed to determine the significance of each factor and interaction
Survival of the Fattest: How Body Fat and Migration Influence Survival in Highly Seasonal Environments
1. Energy stores and migration are important adaptations for animals in seasonal environments, but their roles may vary relative to an animal\u27s endogenous and exogenous environment. In partially migratory populations, migrants and residents experience different seasonal environments; thus, the influence of energy stores on survival may differ relative to migratory tactic, with potential consequences to survival and fitness.
2. Using data from Sierra Nevada bighorn sheep (Ovis canadensis sierrae; hereafter, Sierra bighorn), we tested the hypothesis that body fat (energy stores) buffers animals against their environment, but that buffering capacity differs across environments experienced by high-elevation residents (using a single range year round), traditional migrants (making 1 round-trip movement between high- and low-elevation ranges during winter) and vacillating migrants (making â„2 round trips between high- and low-elevation ranges during winter). We predicted that: for animals with high levels of body fat, survival would be high regardless of migratory tactic; residents would require larger stores of body fat to survive than migrants; energy stores would be least influential to survival for vacillating migrants.
3. High levels of body fat in autumn (â„14% for females and â„19% for males) largely buffered animals against harsh environments (survival \u3e0.90) regardless of migratory tactic. At lower levels of body fat, traditional migrants had higher survival than residents. Vacillating migrants exhibited nearly 100% survival with no detectable effect of body fat on survival.
4. Collectively, these results support the hypothesis that body fat buffers animals against harsh environments but that the buffering capacity differed relative to the environment and highly flexible behaviours (i.e. vacillating migration) can allow animals to decouple survival from body fat.
5. Our work reveals that synergies between physiological and behavioural adaptations of animals in highly seasonal environments carry potential fitness consequences for individuals and demographic consequences for populations
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