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Search Results: 1 - 10 of 407333 matches for " Walter M Boyce "
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Puma predation on radiocollared and uncollared bighorn sheep
Sean M Clemenza, Esther S Rubin, Christine K Johnson, Randall A Botta, Walter M Boyce
BMC Research Notes , 2009, DOI: 10.1186/1756-0500-2-230
Abstract: Three pumas killed 23 bighorn sheep over the course of the study, but they did not preferentially prey on marked (radiocollared) versus unmarked bighorn sheep. Predation occurred primarily during crepuscular and nighttime hours, and 22 kill sites were identified by the occurrence of 2 or more consecutive puma GPS locations (a cluster) within 200 m of each other at 1900, 0000, and 0600 h.We tested the "conspicuous individual hypothesis" and found that there was no difference in puma predation upon radiocollared and uncollared bighorn sheep. Pumas tended to move long distances before and after kills, but their movement patterns immediately post-kill were much more restricted. Researchers can exploit this behaviour to identify puma kill sites and investigate prey selection by designing studies that detect puma locations that are spatially clustered between dusk and dawn.Pumas (Puma concolor) are known predators of bighorn sheep (Ovis canadensis) in North America, but puma behaviour and movements associated with these predation events are poorly understood. Ross et al. [1] found predation on Rocky Mountain bighorn sheep to be an individual behaviour in Alberta, and Logan and Sweanor [2] and Ernest et al. [3] also presented evidence for differences in the frequency that individual pumas killed desert bighorn sheep in the southwestern United States. Although these studies identified individual pumas that selectively killed bighorn sheep, they left important questions unanswered. During ongoing studies of pumas and endangered bighorn sheep in the Peninsular Ranges of California, we radiocollared 3 pumas (1 female and her 2 offspring) who subsequently each killed multiple bighorn sheep (total ≥ 23). This gave us the opportunity to critically evaluate whether or not pumas selectively preyed on radiocollared versus uncollared bighorn sheep (because marked animals are more conspicuous), and to examine movement patterns at and around bighorn sheep kill sites.The Peninsular Rang
Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity
Walter M Boyce, Mara E Weisenberger, M Cecilia T Penedo, Christine K Johnson
BMC Ecology , 2011, DOI: 10.1186/1472-6785-11-5
Abstract: Although the free-ranging source population had significantly higher multi-locus heterozygosity at 30 microsatellite loci than the captive bred animals, neither source population nor genetic background significantly influenced survival or cause of death. The presence of antibodies to a respiratory virus known to cause pneumonia was associated with increased survival, but there was no correlation between genetic heterozygosity and the presence of antibodies to this virus.Although genetic theory predicts otherwise, increased heterozygosity was not associated with increased fitness (survival) among translocated animals. While heterosis or genetic rescue effects may occur in F1 and later generations as the two source populations interbreed, we conclude that previous pathogen exposure was a more important marker than genetic heterozygosity for predicting survival of translocated animals. Every wildlife translocation is an experiment, and whenever possible, translocations should be designed and evaluated to test hypotheses that will further improve our understanding of how pathogen exposure and genetic variability influence fitness.Innate and adaptive immune responses evolved in vertebrates as a first and secondary line of defense, respectively, against a diverse and changing array of pathogenic organisms. The effectiveness of these immunologic responses, and hence the fitness of individuals, populations, and species, is driven by pathogen exposure history and the immunogenetic repertoire of major histocompatibility complex (MHC) genes and non-MHC genes [1,2]. Novel, highly virulent pathogens can overwhelm host immune responses not primed to their exposure, and such pathogens can be a strong selective force, reducing the distribution and abundance of a species over short timeframes (1-2 generations) through effects on survival and reproductive success [2]. Over multiple generations, a history of ongoing pathogen exposure theoretically should select for more resistant immu
Impacts of feral horses on a desert environment
Stacey D Ostermann-Kelm, Edward A Atwill, Esther S Rubin, Larry E Hendrickson, Walter M Boyce
BMC Ecology , 2009, DOI: 10.1186/1472-6785-9-22
Abstract: Horse trailing resulted in reduced vegetation cover, compacted soils, and in cases of intermediate intensity disturbance, increased plant species diversity. The presence of horse feces did not affect plant cover, but it did increase native plant diversity.Adverse impacts, such as soil compaction and increased erosion potential, were limited to established horse trails. In contrast, increased native plant diversity near trails and feces could be viewed as positive outcomes. Extensive trailing can result in a surprisingly large impact area: we estimate that < 30 horses used > 25 km2 of trails in our study area.Zoogeomorphology, the study of the geomorphologic impacts of animals [1], is a relatively new field of research. Ecologists and geomorphologists are placing increasing emphasis on understanding the fundamental role of animals as agents of erosion, transportation, and deposition of sediment [2,3]. Zoogeomorphologic data may be useful to wildlife managers who need to quantify, predict, and manage impacts from feral species on native ecosystems.Zoogeomorphology may be particularly helpful in understanding the controversial role of feral horses (Equus caballus) in native ecosystems [4-8]. Feral horses have a wide geographic range across the southwestern United States and may potentially affect many species through seemingly small changes to the ecosystems they inhabit. For instance, the tendency for feral horses to use landscapes heterogeneously results in the creation of multiple trails [5]. We documented an extensive complex of trails that were used and maintained by feral horses in southern California and similar trail complexes have been documented in Nevada [5]. Horse feces and trails may visually impair the landscape and detract from the experience of some wilderness users. Natural animal trails from a variety of species are well documented, primarily through casual mention in the literature, but little quantitative information on the impacts of animal trails
Impact of the California Lead Ammunition Ban on Reducing Lead Exposure in Golden Eagles and Turkey Vultures
Terra R. Kelly,Peter H. Bloom,Steve G. Torres,Yvette Z. Hernandez,Robert H. Poppenga,Walter M. Boyce,Christine K. Johnson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017656
Abstract: Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites.
Pandemic H1N1 Influenza Isolated from Free-Ranging Northern Elephant Seals in 2010 off the Central California Coast
Tracey Goldstein, Ignacio Mena, Simon J. Anthony, Rafael Medina, Patrick W. Robinson, Denise J. Greig, Daniel P. Costa, W. Ian Lipkin, Adolfo Garcia-Sastre, Walter M. Boyce
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062259
Abstract: Interspecies transmission of influenza A is an important factor in the evolution and ecology of influenza viruses. Marine mammals are in contact with a number of influenza reservoirs, including aquatic birds and humans, and this may facilitate transmission among avian and mammalian hosts. Virus isolation, whole genome sequencing, and hemagluttination inhibition assay confirmed that exposure to pandemic H1N1 influenza virus occurred among free-ranging Northern Elephant Seals (Mirounga angustirostris) in 2010. Nasal swabs were collected from 42 adult female seals in April 2010, just after the animals had returned to the central California coast from their short post-breeding migration in the northeast Pacific. Swabs from two seals tested positive by RT-PCR for the matrix gene, and virus was isolated from each by inoculation into embryonic chicken eggs. Whole genome sequencing revealed greater than 99% homology with A/California/04/2009 (H1N1) that emerged in humans from swine in 2009. Analysis of more than 300 serum samples showed that samples collected early in 2010 (n = 100) were negative and by April animals began to test positive for antibodies against the pH1N1 virus (HI titer of ≥1:40), supporting the molecular findings. In vitro characterizations studies revealed that viral replication was indistinguishable from that of reference strains of pH1N1 in canine kidney cells, but replication was inefficient in human epithelial respiratory cells, indicating these isolates may be elephant seal adapted viruses. Thus findings confirmed that exposure to pandemic H1N1 that was circulating in people in 2009 occurred among free-ranging Northern Elephant Seals in 2010 off the central California coast. This is the first report of pH1N1 (A/Elephant seal/California/1/2010) in any marine mammal and provides evidence for cross species transmission of influenza viruses in free-ranging wildlife and movement of influenza viruses between humans and wildlife.
Avian Influenza: Mixed Infections and Missing Viruses
LeAnn L. Lindsay,Terra R. Kelly,Magdalena Plancarte,Seth Schobel,Xudong Lin,Vivien G. Dugan,David E. Wentworth,Walter M. Boyce
Viruses , 2013, DOI: 10.3390/v5081964
Abstract: A high prevalence and diversity of avian influenza (AI) viruses were detected in a population of wild mallards sampled during summer 2011 in California, providing an opportunity to compare results obtained before and after virus culture. We tested cloacal swab samples prior to culture by matrix real-time PCR, and by amplifying and sequencing a 640bp portion of the hemagglutinin (HA) gene. Each sample was also inoculated into embryonated chicken eggs, and full genome sequences were determined for cultured viruses. While low matrix Ct values were a good predictor of virus isolation from eggs, samples with high or undetectable Ct values also yielded isolates. Furthermore, a single passage in eggs altered the occurrence and detection of viral strains, and mixed infections (different HA subtypes) were detected less frequently after culture. There is no gold standard or perfect reference comparison for surveillance of unknown viruses, and true negatives are difficult to distinguish from false negatives. This study showed that sequencing samples prior to culture increases the detection of mixed infections and enhances the identification of viral strains and sequences that may have changed or even disappeared during culture.
String Inspired QCD and $E_6$ Models
M. M. Boyce
Physics , 1996,
Abstract: The work in this thesis consists of two distinct parts: A class of models called, ``String-flip potential models,'' (SFP's) are studied as a possible candidate for modeling nuclear matter in terms of constituent quarks. These models are inspired from lattice quantum-chromodynamics (QCD) and are nonperturbative in nature. It is shown that they are viable candidates for modeling nuclear matter since they reproduce most of the bulk properties except for nuclear binding. Their properties are studied in nuclear and mesonic matter. A new class of models is developed, called ``flux-bubble potential models,'' which allows for the SFP's to be extended to include perturbative QCD interactions. Attempts to obtain nuclear binding is not successful, but valuable insight was gained towards possible future directions to pursue. The possibility of studying Superstring inspired $E_6$ phenomenology at high energy hadron colliders is investigated. The production of heavy lepton pairs {\it via} a gluon-gluon fusion mechanism is discussed. An enhancement in the parton level cross-section is expected due to the heavy (s)fermion loops which couple to the gluons.
Adoption of alcohol hand disinfection in the United States: a personal perspective
Boyce, John M.
GMS Krankenhaushygiene Interdisziplin?r , 2007,
Abstract: Even though alcohol-based hand disinfectants have been used for decades as a routine measure in Europe, in the USA until recently handwashing was the procedure of choice. Alcohol-based rub products were recommended only if no handwashing facility or running water was available. It was only during the late 80s and early 90s that the advantages of alcohol-based products began to elicit interest. In 1995 Larsen published new application guidelines for hand disinfection and in 1996 the CDC included alcohol-based hand disinfection in its “Isolation guideline”. However, these recommendations were rarely implemented in practice. In 1996 Didier Pittet first gave me a demonstration of alcohol-based rub products at his Geneva hospital, and the following year experts at Lausanne University provided me with the products available at that time. In 1998 and 2000 I had the opportunity to exchange information and experiences with numerous European experts, including Dr. Molitor, who also gave me additional insights into the mechanism of action of such products. As a result of myriad scientific demonstrations, interest in these rub products now began to be expressed in the USA too. In 1999 an interdisciplinary working group for hand hygiene was set up, comprising representatives from CDC’s Healthcare Infection Control Practices Advisory Committee (HICPAC), the Society for Healthcare Epidemiology of America, the Association for Professionals in Infection Control and the Infectious Diseases Society of America, whose intention was to formulate new guidelines for hand hygiene in the healthcare sector. The insights that I gained from Dr. Molitor and from other European experts were of enormous value and helped to weigh up the pros and cons of alcohol-based hand disinfection, both in respect of the different products available and on comparing them with hand washing. The new CDC guideline for hand hygiene was published in 20002 and for the first time in the USA it featured the requirement that alcohol-based rub products be used as the method of choice provided that the hands were not visibly soiled or contaminated with protein-based material. Unfortunately, we have no reliable data, but it is estimated that today up to 95% of doctors and nurses in American hospitals preferentially use alcohol-based rub products – thus reflecting a situation that has long been common practice in Europe.
Three Pathogens in Sympatric Populations of Pumas, Bobcats, and Domestic Cats: Implications for Infectious Disease Transmission
Sarah N. Bevins, Scott Carver, Erin E. Boydston, Lisa M. Lyren, Mat Alldredge, Kenneth A. Logan, Seth P. D. Riley, Robert N. Fisher, T. Winston Vickers, Walter Boyce, Mo Salman, Michael R. Lappin, Kevin R. Crooks, Sue VandeWoude
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031403
Abstract: Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases – vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii – varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better understand the mechanisms driving disease exposure and to predict zones of cross-species pathogen transmission among wild and domestic felids.
Recovering from Libet’s Left Turn into Veto-as-Volition:A Proposal for Dealing Honestly with the Central Mystery of Libet (1983)  [PDF]
Conal Boyce
Open Journal of Philosophy (OJPP) , 2012, DOI: 10.4236/ojpp.2012.21003
Abstract: With certain topics the general reader experiences a double-whammy wherein one must peer through a curtain of needlessly obscure jargon to try glimpsing something that is inherently weird in nature. Bell’s nonlocality was once such a topic, but authors have had considerable success over the years in showing where the line is between the enigma itself (in nature) and the human-made oddities surrounding it (in physics). Libet-ology has yet to undergo that de-mystifying process. Accordingly, our first order of business here is to restate its basic tenets in plain English so that only nature’s inherent puzzle is left on the table, free of certain peculiarities of the existing technical literature. We also address the question of the central topic versus its byways, as alluded to by ‘left turn into veto-as-volition’ in our title. (On the final page of Libet’s landmark paper, there is an effort to resurrect free will in the same breath that implicitly just killed it. In this way, the founder of the field placed it into perennial disarray and left its true message in obscurity for decades.) In the ensuing parts of the paper, we look outside the field to see how hypnotherapy and Hinduism might shed light on it.
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