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Momany, Y., S. R. Zaggia, P. Bonifacio, G. Piotto, F. De Angeli, L. R. Bedin, and G. Carraro. "Probing the Canis Major stellar over-density as due to the Galactic warp." Astronomy & Astrophysics 421, no. 2 (June 22, 2004): L29—L32. http://dx.doi.org/10.1051/0004-6361:20040183.
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Momany, Y., S. Zaggia, G. Gilmore, G. Piotto, G. Carraro, L. R. Bedin, and F. De Angeli. "Outer structure of the Galactic warp and flare: explaining the Canis Major over-density." Astronomy & Astrophysics 451, no. 2 (May 2006): 515–38. http://dx.doi.org/10.1051/0004-6361:20054081.
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López-Corredoira, M., Y. Momany, S. Zaggia, and A. Cabrera-Lavers. "Re-affirming the connection between the Galactic stellar warp and the Canis Major over-density." Astronomy & Astrophysics 472, no. 3 (August 6, 2007): L47—L50. http://dx.doi.org/10.1051/0004-6361:20077813.
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Xu*, Xia, Zhongbo Ren, and Jiang Lu. "Appearance of Xylella Fastidiosa in Pierce's Disease resistant and Susceptible Grapevines." HortScience 39, no. 4 (July 2004): 826B—826. http://dx.doi.org/10.21273/hortsci.39.4.826b.
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Pierce's Disease (PD) is a major factor limiting grape production in the southeast United State. This disease is caused by a bacterium, Xylella fastidiosa Wells et al., which is transmitted to the xylem system of the grapevines primarily by glassy-winged sharpshooters (Homalodisca coagulata Say). Once it is in the xylem, the X. fastidiosa will use the xylem sap as a nutrient source to multiply, colonize, and eventually plug the xylem vessels and cause the PD in susceptible cultivars. On the other hand, symptoms of PD in tolerant cultivars do not appear until fruit maturation, and symptoms are rarely observed in PD resistant cultivars. In order to understand the correlation between X. fastidiosa and PD symptom development, a study was initialed to monitor X. fastidiosa in xylem of resistant, tolerant, and susceptible vines on a monthly basis. Presence of X. fastidiosa was detected directly from xylem sap of field-grown vines by medium culture and confirmed by polymerase chain reaction (PCR). Xylella fastidiosa was detectable throughout the growing season in PD susceptible cultivar `Chardonnay', PD tolerant Florida hybrid grape `Blanc du Bois', and muscadine cultivar `Carlos'. The bacteria were also appeared in the dormant vines with high density in cultivars `Chardonnay' and `Blanc du Bios'. Although X. fastidiosa was also found in dormant canes of `Carlos', the density decreased throughout the late fall and winter months, and they were hardly found before June. The results indicated that X. fastidiosa were carried over from previous season in cultivars `Chardonnay' and `Blanc du Bois', while in PD tolerant cultivar `Carlos', they were newly acquired from the sharpshooter feedings during the growing season.
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Fritzsons, Elenice, and Luiz Eduardo Montavani. "Os Substratos Geológicos e os Coeficientes Morfométricos em Bacias Hidrográficas do Carste Dolomítico no Estado do Paraná (The Geological Substrates and Morphometric Coefficients in Dolomitic Karst in State of Paraná)." Revista Brasileira de Geografia Física 3, no. 3 (February 16, 2011): 181. http://dx.doi.org/10.26848/rbgf.v3i3.232662.
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Os estudos de morfometria de bacias hidrográficas e da rede de drenagem têm contribuído para a compreensão da evolução da paisagem. Nos trópicos e subtrópicos, a ação das precipitações exerce uma função dominante na evolução dos canais de drenagem e as estruturas geológicas modulam a forma e a densidade da rede hidrográfica. O presente trabalho visa estabelecer algumas relações entre índices morfométricos de bacias hidrográficas e a litologia das bacias. O trabalho foi desenvolvido na bacia superior da rede hidrográfica do Rio Ribeira de Iguape. A área foi subdividida 10 sub-bacias e nelas foram obtidos os seguintes parâmetros morfométricos: densidade de drenagem (Dd), sinuosidade do rio principal (Sin), coeficiente de compacidade (Kc), amplitude altimétrica (AA), fator de forma (Kf), relação de relevo (Rr), densidade hidrográfica (Dh), índice de circularidade (IC). Os índices morfométricos foram submetidos à análise de agrupamento (cluster Ward’s method) para agrupar as bacias com morfometrias semelhantes. Concluiu-se, a partir do resultado da análise de cluster, que os grupos formados apresentaram boa correlação com o substrato geológico. Para resultados mais conclusivos, outros estudos nesta área devem ser feitos com um maior número de bacias contendo outros arranjos litológicos e com novos índices sendo incorporados na análise.Palavras chave: morfometria, substrato geológico, análise multivariada, hidrologia The Geological Substrates and Morphometric Coefficients in Dolomitic Karst in State of Paraná ABSTRACT Morphometric studies of watersheds and drainage network have contributed to understand landscape evolution. In the tropics and subtropics, where precipitation represents a major force in modeling slopes and drainage channels, the geologic structure affects the formation of the drainage network. The major aim of this study was to investigate the relationship between watersheds morphometric indices and lithology. The study was conducted in the upper basin of the coastal Ribeira Valley river system, in Paraná State, Brazil. The area was subdivided into 10 sub-basins and over them we did estimated the following morphometric parameters: drainage density (Dd), sinuosity of the main stream (Sin), the compactness coefficient (Kc) altimetric amplitude (AA), shape factor (Kf), relief ratio (Rr), hydrographic density (Dh), circularity index (CI). The cluster analysis (Ward’s method) was applied to the indices in order to group basins with similar morphometry. We conclude that the hierarchical groups formed by cluster analysis show a good correlation with geological substratum. For more conclusive results, others similar thematic studies should be done with a larger number of catchments, working with different lithologies and by testing other mophometric indices. Keywords: morphometry, geological substrate, multivariate analysis, hidrology
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Crabtree, Robert. "Effects of 1988 Fires on Ecology of Coyotes in Yellowstone National Park: Baseline Preceding Possible Wolf Recovery." UW National Parks Service Research Station Annual Reports 16 (January 1, 1992): 179–83. http://dx.doi.org/10.13001/uwnpsrc.1992.3111.
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Sixty-five healthy coyote (Canis latrans) adults and 53, 8-12 week old pups captured at dens were radio-tagged in the Lamar Valley and Blacktail Plateau areas of the northern range of Yellowstone National Park. Adults range in age from 1 to 11 years and averaged nearly 3 years old. Territorial packs in both study areas are adjacent, nonÂoverlapping, contiguous, and averaged 15 km2. Based on information the last three winters and data collected from 1946 to 1949, territorial areas are traditional and have changed little in the last 45 years. We estimate that 85 to 90% of coyotes on the northern range belong to packs. A territorial group or pack during the winter consists of 2 alpha individuals, 2 or 3 beta adults, and 2 or 3 adult-sized pups (average pack size = 7). Only one radioed adult coyote has died since May of 1992. Twenty four of 53 pups have died between the ages of 3 and 9 months old. Population productivity ranges from 1.8 to 2.5 pups recruited per territory. The reproductive failure rate among breeding groups averaged 15% during 1990 and 1991. Initial density estimates are 1.4 coyotes per square mile. Intensive foraging observations were conducted from January through June 1991 (353 hours) and from November 1991 through April 1992 (1100+hours). Focal observations collected from January-June 1991 resulted in 427 capture attempts on small mammal prey with 162 (38%) successful. Habitat type played a key role in the success rate. Preliminary analysis of the November 1991 to April1992 data indicated a substantial reduction in prey attempts and prey success. This reduction was mostly a function of harsh snow conditions in early winter and abundlint elk carrion in late winter. Over eighty ungulate carcass were located this winter in the 2 study areas. However, small mammals, especially voles, dominate the diet with ungulate remains becoming important in May through July (presumably elk calves) and late winter (mostly scavenging). We have documented numerous successful and unsuccessful predation attempts on ungulates in our study areas. Coyotes appear to impact ungulate numbers in 3 ways: predation on calves and fawns shortly after birth (up to 8 weeks), predation on short-yearlings and adults during winter, and indirect impact from harassment of other predators at ungulate-kills. Coyotes may be the major ungulate predator on the northern range due to cooperative social and foraging behavior, their ability to take advantage of vulnerable ungulates, and their high population levels. Wolf extirpation has probably resulted in high coyote population densities and coyotes have, at least, partially slid into this vacant niche.
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Seip, Dale R., and Kent Brown. "Introduction to the Population Ecology of North American Caribou." Rangifer 16, no. 4 (January 1, 1996): 11. http://dx.doi.org/10.7557/2.16.4.1214.
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Bergerud has discussed how major differences in caribou density across North America appear to be related to the impact of wolf (Canis lupus) predation, and the strategies used by caribou to avoid wolves. Caribou living in areas without wolves usually occur at high densities and are regulated by competition for food. In this session, we asked the presenters to discuss the population ecology of different caribou herds in North America and to evaluate if they fit the general model.
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Ballenberghe, Victor Van, and Warren B. Ballard. "Limitation and regulation of moose populations: the role of predation." Canadian Journal of Zoology 72, no. 12 (December 1, 1994): 2071–77. http://dx.doi.org/10.1139/z94-277.
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An improved understanding of factors limiting and regulating ungulate populations is vital for sound management, especially with regard to controversial factors like predation. We examine the claim that evidence is weak for predation acting as a major factor limiting or regulating moose (Alces alces) populations in North America. Biologists have been inconsistent in defining limitation and regulation, have used these terms interchangeably, and have incorrectly assumed that major limiting factors regulate moose density. Empirical evidence indicates that many moose populations preyed on by both bears (Ursus arctos and U. americana) and wolves (Canis lupus) persist at densities much lower than K/2 when human influence is minimal. Under these conditions, reduction of predator numbers often results in increased moose density. Reduction of moose from high densities with predators held constant results in inversely density-dependent (anti-regulatory) predation and low moose densities for prolonged periods. In ecosystems lacking bears, or in those subject to substantial human influence, predation may not be a major limiting factor, may vary greatly in its impact, and may be overshadowed by interactions among moose, forage, weather, and hunting that primarily determine moose density. We conclude that in naturally regulated ecosystems, predation on moose by bears and wolves is often limiting and may be regulating, and we identify the conditions necessary for this to occur.
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Taques, Isis Indaiara Gonçalves Granjeiro, Amanda Noeli Silva Campos, Mayara Lima Kavasaki, Sayanne Luns Hatum de Almeida, and Daniel Moura de Aguiar. "Geographic Distribution of Ehrlichia canis TRP Genotypes in Brazil." Veterinary Sciences 7, no. 4 (October 29, 2020): 165. http://dx.doi.org/10.3390/vetsci7040165.
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Tandem repeat proteins (TRPs) are major immunoreactive proteins of Ehrlichia canis, which have been used in the serological diagnosis of different genotypes of the microorganism. TRP19 is preserved among different E. canis isolates expressed on both reticulate and dense-core cells and observed in the extracellular matrix or associated with the morula membrane. TRP36 is differentially expressed only on the surface of the dense-core form of the bacterium and exhibits more divergence among isolates. The aim of this study was to evaluate the distribution of the American (USTRP36), Brazilian (BrTRP36) and Costa Rican (CRTRP36) genotypes of E. canis in Brazil, using ELISA assays. Serum samples of 814 dogs from 49 municipalities from all over Brazil were analyzed. Our results showed that 34% of the samples were reactive to the USTRP36 genotype and 32.6% to the BrTRP36 genotype. The two genotypes appeared to occur equally throughout Brazil, although the frequency of seropositivity was lower in the south than in the country’s other regions. Dogs that reacted to at least one of the synthetic peptides (TRP19 and TRP36) were 456 (56%). A few dogs (n = 5; 0.61%) reactive to the E. canis TRP36 genotype (CRTRP36) were also detected in the northeast and southern regions. We concluded that the American and Brazilian genotypes of E. canis are distributed evenly in Brazil, especially in the tropical region, while the temperate region in the south presented the lowest prevalence rates. This study offers the first report of dogs seropositive for the Costa Rican genotype in Brazil.
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O'Lorcain, P. "Prevalence of Toxocara canis ova in public playgrounds in the Dublin area of Ireland." Journal of Helminthology 68, no. 3 (September 1994): 237–41. http://dx.doi.org/10.1017/s0022149x00014401.
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AbstractA total of nine playground sites in Dublin city and county were surveyed from which 228 samples were removed. Of these samples, 15% were positive for Toxocara canis ova and a mean egg density of 1.4 ova/100 g was calculated. Two types of playground sites were identified and that the level of toxocaral contamination was found to be greater in ‘neighbourhood playgrounds’ than in ‘adventure playgrounds’. There was no significant difference in the number of positive samples taken from sites both inside and outside these playgrounds. No evidence of Toxocara cati ova was found. Only one sample was positive for Toxascaris leonina ova. Over 50% of the T. canis ova identified were infective. The findings in this study suggest that the sample's moisture content contributes to the long term survival of infective Toxocara ova in the environment. A recovery rate of 69.8% was achieved with a modified version of the flotation method.
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Seip, Dale R. "Predation and caribou populations." Rangifer 11, no. 4 (October 1, 1991): 46. http://dx.doi.org/10.7557/2.11.4.993.
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Predation, especially wolf (Canis lupus) predation, limits many North American caribou (Rangifer tarandus) populations below the density that food resources could sustain. The impact of predation depends on the parameters for the functional and numerical response of the wolves, relative to the potential annual increment of the caribou population. Differences in predator-avoidance strategies largely explain the major differences in caribou densities that occur naturally in North America. Caribou migrations that spatially separate caribou from wolves allow relatively high densities of caribou to survive. Non-migratory caribou that live in areas where wolf populations are sustained by alternate prey can be eliminated by wolf predation.
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Dumond, M., and M. A. Villard. "Demography and body condition of coyotes (Canis latrans) in eastern New Brunswick." Canadian Journal of Zoology 78, no. 3 (April 1, 2000): 399–406. http://dx.doi.org/10.1139/z99-223.
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We documented the demography and body condition of coyotes (Canis latrans), using 77 carcasses collected in late fall and winter (1995-1996 and 1996-1997) during an increase in snowshoe hare (Lepus americanus) density in eastern New Brunswick. We compared body condition at the beginning (November-January) and end of winter (February-March) in relation to breeding status. Physical characteristics of coyotes were similar to those reported elsewhere in the northeastern portion of its range. The sex ratio did not differ significantly from 1:1. The population was unusually old (5.6 ± 0.4 years of age (mean ± SE)). The parturition rate was low (40.9% in adult females), and placental scars were present only in females >5 years old (6.6 ± 0.6 scars per female). There was no significant decrease in the body condition of adult females over the winter but the body mass of those females with placental scars tended to decrease over the winter (P = 0.012). Also, during November-January, reproductive females (with placental scars) were significantly heavier (P = 0.007) than non-reproductive adult females (without placental scars). Our results suggest that in the coyote populations in eastern New Brunswick, breeding status and reproductive costs should be taken into account in future studies of demography and body condition. Also, the low level of coyote exploitation by humans may be responsible for the old age structure of the population and the low parturition rate. The exploitation level should be considered when analyzing coyote sociodemographic data.
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Long, Sarah, Hope Carveth, Yu-Mei Chang, Dan O’Neill, and Ross Bond. "Isolation of dermatophytes from dogs and cats in the South of England between 1991 and 2017." Veterinary Record 187, no. 10 (September 21, 2020): e87-e87. http://dx.doi.org/10.1136/vr.105957.
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BackgroundSince the epidemiology of canine and feline dermatophytosis might evolve in response to chronological, sociological and ecological factors, the authors studied the occurrence of dermatophyte pathogens over 27 years subsequent to the last major UK survey.MethodsDermatophyte culture submission records from dogs and cats to the Royal Veterinary College Diagnostic Laboratory in England between 1991 and 2017 were reviewed. Samples were routinely cultured aerobically at 26°C for up to four weeks on Sabouraud’s dextrose agar containing cycloheximide and chloramphenicol; dermatophytes were identified using conventional phenotypic methods.ResultsProportional isolation from cats (15.9 per cent of 1389) exceeded that of dogs (8.1 per cent of 2193) (P<0.001). Together, Microsporum canis and Trichophyton mentagrophytes accounted for 91.9 per cent (n=203) and 80.2 per cent (n=142) of isolations from cats and dogs, respectively. M canis was more frequently (P<0.001) isolated from cats and dogs under two years of age. Dermatophytes were more frequent (P≤0.001) in samples from first-opinion rather than referral practice, and from Jack Russell and Yorkshire terriers and from Persian and chinchilla cats (P≤0.002).ConclusionsM canis and T mentagrophytes remain the most common agents of canine and feline dermatophytosis in the South of England; continued clinical vigilance is required.
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Długosz, Ewa, Małgorzata Milewska, and Piotr Bąska. "Identification of Toxocara canis Antigen-Interacting Partners by Yeast Two-Hybrid Assay and a Putative Mechanism of These Host–Parasite Interactions." Pathogens 10, no. 8 (July 28, 2021): 949. http://dx.doi.org/10.3390/pathogens10080949.
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Toxocara canis is a zoonotic roundworm that infects humans and dogs all over the world. Upon infection, larvae migrate to various tissues leading to different clinical syndromes. The host–parasite interactions underlying the process of infection remain poorly understood. Here, we describe the application of a yeast two-hybrid assay to screen a human cDNA library and analyse the interactome of T. canis larval molecules. Our data identifies 16 human proteins that putatively interact with the parasite. These molecules were associated with major biological processes, such as protein processing, transport, cellular component organisation, immune response and cell signalling. Some of these identified interactions are associated with the development of a Th2 response, neutrophil activity and signalling in immune cells. Other interactions may be linked to neurodegenerative processes observed during neurotoxocariasis, and some are associated with lung pathology found in infected hosts. Our results should open new areas of research and provide further data to enable a better understanding of this complex and underestimated disease.
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O'Neil, Shawn T., Dean E. Beyer, and Joseph K. Bump. "Territorial landscapes: incorporating density-dependence into wolf habitat selection studies." Royal Society Open Science 6, no. 11 (November 2019): 190282. http://dx.doi.org/10.1098/rsos.190282.
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Habitat selection is a process that spans space, time and individual life histories. Ecological analyses of animal distributions and preferences are most accurate when they account for inherent dynamics of the habitat selection process. Strong territoriality can constrain perception of habitat availability by individual animals or groups attempting to colonize or establish new territory. Because habitat selection is a function of habitat availability, broad-scale changes in habitat availability or occupancy can drive density-dependent habitat functional responses. We investigated density-dependent habitat selection over a 19-year period of grey wolf ( Canis lupus ) recovery in Michigan, USA, using a generalized linear mixed model framework to develop a resource selection probability function (RSPF) with habitat coefficients conditioned on random effects for wolf packs and random year intercepts. In addition, we allowed habitat coefficients to vary as interactions with increasing wolf density over space and time. Results indicated that pack presence was driven by factors representing topography, human development, winter prey availability, forest structure, roads, streams and snow. Importantly, responses to many of these predictors were density-dependent. Spatio-temporal dynamics and population changes can cause considerable variation in wildlife–habitat relationships, possibly confounding interpretation of conventional habitat selection models. By incorporating territoriality into an RSPF analysis, we determined that wolves' habitat use in Michigan shifted over time, for example, exhibiting declining responses to winter prey indices and switching from positive to negative responses with respect to stream densities. We consider this an important example of a habitat functional response in wolves, driven by colonization, density-dependence and changes in occupancy during a time period of range expansion and population increase.
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Richard, Glory, and Ebinyo Rebecca Aseibai. "Seasonal Variation in Mycological Quality of Air Environment Around a Major Market Along East-West Road in Bayelsa State, Nigeria." International Journal of Healthcare and Medical Sciences, no. 72 (March 29, 2021): 18–25. http://dx.doi.org/10.32861/ijhms.72.18.25.
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The distribution of bio-aerosols in diverse environments is a major concern to aero-microbiologists and environmentalists in general. The study evaluated the mycological quality of the air environment around a market along East-West road in Bayelsa State, Nigeria. Petri dish containing sterile Potatoes dextrose agar was exposed for 10 minutes around a market along East-West road in Bayelsa state at a height of 1 meter. The density and diversity of the isolates were determined following standard mycological procedures. The density of the fungi–aerosols ranged from 0.0073 - 0.0268 CFU/min-m2 and was statistical higher in dry (November, January and March) compared to wet (May, July and September) seasons, an indication of seasonal influence. A total of 11 fungi species were recorded with 5 predominant species viz Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Fusarium chlamydosporum and Penicillium species (occurring in ≥66.67% of the study months), while 6 species, Aspergillus lentulus, Aspergillus nidulans, Aspergillus terreus, Cladosporium cladosporioides, Microsporum canis and Mucor species are opportunistic occurring in ≤50% of the study months). Most fungi species are found in the soil, and are known to produce toxins and cause diseases. There is need for a concerted effort by local government authorities via its agencies to sensitize people on proper hygiene practices around markets.
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Telfer, Edmund S. "Continuing Environmental Change - An Example from Nova Scotia." Canadian Field-Naturalist 118, no. 1 (January 1, 2004): 39. http://dx.doi.org/10.22621/cfn.v118i1.880.
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Information from personal experience, from community elders and published literature served as a basis for evaluating environmental changes in the District of North Queens and adjacent areas of Southwestern Nova Scotia over the past century. Major events included disappearance of the Caribou (Rangifer tarandus), the arrival of White-tailed Deer (Odocoileus virginianus), the severe reduction of Canada Yew (Taxus canadensis), disappearance of Lynx (Lynx canadensis), a major dieoff of Striped Skunks (Mephitis mephitis), decline of American Beech (Fagus grandifolia), the loss of mature birch (Betula spp.), the severe reduction of Moose (Alces alces), the arrival of the American Dog Tick (Dermacentor variabilis) and Coyotes (Canis latrans), and the restoration of Beaver (Castor canadensis). The proximate cause of many of those changes were plant and animal disease, while the ultimate causes were naturally occurring animal range expansion and human impacts. The warming of the climate over the past 150 years probably played a role. The nature and timing of the events could not have been predicted.
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Seip, D. R., and D. B. Cichowski. "Population Ecology of Caribou in British Columbia." Rangifer 16, no. 4 (January 1, 1996): 73. http://dx.doi.org/10.7557/2.16.4.1223.
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The abundance and geographic range of woodland caribou (Rangifer tarandus caribou) decreased in many areas of British Columbia during the 1900's. Recent studies have found that predation during the summer is the major cause of mortality and current population declines. Increased moose {Alecs alces) populations may be related to past and current caribou declines by sustaining greater numbers of wolves (Canis lupus). Mortality rates were greater in areas where caribou calved in forested habitats, in close proximity to predators and moose. Caribou populations which had calving sites in alpine areas, islands, and rugged mountains experienced lower mortality and were generally stable or increasing. A predator-induced population decline in one area appeared to stabilize at low caribou densities, suggesting that the wolf predation rate may be density dependent.
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Unver, Ahmet, Yasuko Rikihisa, Norio Ohashi, Louis C. Cullman, Richard Buller, and Gregory A. Storch. "Western and Dot Blotting Analyses of Ehrlichia chaffeensis Indirect Fluorescent-Antibody Assay-Positive and -Negative Human Sera by Using Native and Recombinant E. chaffeensis and E. canis Antigens." Journal of Clinical Microbiology 37, no. 12 (1999): 3888–95. http://dx.doi.org/10.1128/jcm.37.12.3888-3895.1999.
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Human monocytic ehrlichiosis is an emerging infectious disease caused by Ehrlichia chaffeensis, a gram-negative obligatory intracellular bacterium closely related to E. canis. The immunoreactive recombinant fusion proteins rP28 and rP30 have become available after cloning and expressing of the 28- and 30-kDa major outer membrane protein genes of E. chaffeensis and E. canis, respectively. Western immunoblotting was performed to analyze the antibody responses of the 37 E. chaffeensisindirect fluorescent-antibody assay (IFA)-positive and 20 IFA-negative serum specimens with purified whole organisms, rP28, and rP30. All IFA-negative sera were negative with purified whole organisms, rP28, or rP30 by Western immunoblot analysis (100% relative diagnostic specificity). Of 37 IFA-positive sera, 34 sera reacted with any native proteins of E. chaffeensis ranging from 44 to 110 kDa, and 30 sera reacted with 44- to 110-kDa native E. canisantigens. The 28-kDa E. chaffeensis and 30-kDa E. canis native proteins were recognized by 25 IFA-positive sera. Fifteen IFA-positive sera reacted with rP28 by Western blot analysis, whereas 34 IFA-positive sera reacted with rP30 (92% relative diagnostic specificity), indicating that rP30 is more sensitive than rP28 for detecting the antibodies in IFA-positive sera. These 34 IFA-positive sera were positive by the dot blot assay with rP30, distinguishing them from IFA-negative sera. Except for three rP30-negative but IFA-positive specimens that instead showed anE. ewingii infection-like profile by Western immunoblotting, the results of Western and dot blot assays with rP30 matched 100% with the IFA test results. Densitometric analysis of dot blot reactions showed a positive correlation between the dot density and the IFA titer. These results suggest that rP30 antigen would provide a simple, consistent, and rapid serodiagnosis for human monocytic ehrlichiosis.
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Lyons, Mitchell B., Charlotte H. Mills, Christopher E. Gordon, and Mike Letnic. "Linking trophic cascades to changes in desert dune geomorphology using high-resolution drone data." Journal of The Royal Society Interface 15, no. 144 (July 2018): 20180327. http://dx.doi.org/10.1098/rsif.2018.0327.
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Vegetation cover is fundamental in the formation and maintenance of geomorphological features in dune systems. In arid Australia, increased woody shrub cover has been linked to removal of the apex predator (Dingoes, Canis dingo ) via subsequent trophic cascades. We ask whether this increase in shrubs can be linked to altered physical characteristics of the dunes. We used drone-based remote sensing to measure shrub density and construct three-dimensional models of dune morphology. Dunes had significantly different physical characteristics either side of the ‘dingo-proof fence’, inside which dingoes are systematically eradicated and shrub density is higher over vast spatial extents. Generalized additive models revealed that dunes with increased shrub density were higher, differently shaped and more variable in height profile. We propose that low shrub density induces aeolian and sedimentary processes that result in greater surface erosion and sediment transport, whereas high shrub density promotes dune stability. We speculate that increased vegetation cover acts to push dunes towards an alternate stable state, where climatic variation no longer has a significant effect on their morphodynamic state within the bi-stable state model. Our study provides evidence that anthropogenically induced trophic cascades can indirectly lead to large-scale changes in landscape geomorphology.
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McPhee, Heather M., Nathan F. Webb, and Evelyn H. Merrill. "Hierarchical predation: wolf (Canis lupus) selection along hunt paths and at kill sites." Canadian Journal of Zoology 90, no. 5 (May 2012): 555–63. http://dx.doi.org/10.1139/z2012-021.
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Predation is a hierarchical process whereby a predator is constrained to killing prey within the area they select while hunting. We demonstrate the hierarchical nature of predation using movement data from six GPS-collared wolves ( Canis lupus L., 1758) in the Rocky Mountains of Alberta, Canada, by coupling the kill locations of their ungulate prey with their preceding hunt path. Selection of where to hunt constrained the characteristics influencing where wolves killed within hunt paths. Specifically, wolves selected to hunt where prey densities were higher than the mean density for their territories, but prey densities were not related to kill site locations within the selected hunt path. Wolves selected to hunt in open valleys and near habitat edges, where prey may be most predictable, detectable, or vulnerable, which may have been reinforced by a higher likelihood of killing within these characteristics along hunt paths. In contrast, wolves selected to hunt relatively farther from frozen water bodies and closer to well sites than kill site locations, indicating different processes were occurring during the hunting and killing phases. Treating predation as a hierarchical sequence will ensure the role of prey and landscape characteristics on the processes of predation are not over- or under-emphasized by decoupling kill sites from hunt paths, which will lead to a better mechanistic understanding of predation in heterogeneous environments.
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Merkle, J. A., D. R. Stahler, and D. W. Smith. "Interference competition between gray wolves and coyotes in Yellowstone National Park." Canadian Journal of Zoology 87, no. 1 (January 2009): 56–63. http://dx.doi.org/10.1139/z08-136.
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Factors influencing the outcome of interspecific interactions between sympatric carnivores, along with population-level consequences, are not clearly understood. The reintroduction of gray wolves ( Canis lupus L., 1758) to Yellowstone National Park provides a rare opportunity to study interactions with coyotes ( Canis latrans Say, 1823), which had lived in the absence of wolves for >60 years. We evaluated direct interactions between wolves and coyotes to identify factors influencing the outcomes of interspecific interactions and describe the context and degree of competition and coexistence. Using radio-collared wolves, we documented 337 wolf–coyote interactions from 1995 to 2007. The majority (75%) of interactions occurred at ungulate-carcass sites. Wolves initiated the majority of encounters (85%), generally outnumbered coyotes (39%), and dominated (91%) most interactions. Wolves typically (79%) chased coyotes without physical contact; however, 25 interactions (7%) resulted in a coyote death. Interactions decreased over time, suggesting coyote adaptation or a decline in coyote density. In the majority (80%) of fatal interactions, wolves outnumbered coyotes. However, wolves did not outnumber coyotes in interactions (n = 18) where coyotes chased or attacked/harassed wolves. Our results suggest that wolves are the dominant canid, group size may influence the outcome of interactions, and coyotes must benefit from the access to carrion at wolf-killed carcasses.
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Alexander, Justine S., Jeremy J. Cusack, Chen Pengju, Shi Kun, and Philip Riordan. "Conservation of snow leopards: spill-over benefits for other carnivores?" Oryx 50, no. 2 (October 26, 2015): 239–43. http://dx.doi.org/10.1017/s0030605315001040.
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AbstractIn high-altitude settings of Central Asia the Endangered snow leopard Panthera uncia has been recognized as a potential umbrella species. As a first step in assessing the potential benefits of snow leopard conservation for other carnivores, we sought a better understanding of the presence of other carnivores in areas occupied by snow leopards in China's Qilianshan National Nature Reserve. We used camera-trap and sign surveys to examine whether other carnivores were using the same travel routes as snow leopards at two spatial scales. We also considered temporal interactions between species. Our results confirm that other carnivores, including the red fox Vulpes vulpes, grey wolf Canis lupus, Eurasian lynx Lynx lynx and dhole Cuon alpinus, occur along snow leopard travel routes, albeit with low detection rates. Even at the smaller scale of our camera trap survey all five carnivores (snow leopard, lynx, wolf, red fox and dhole) were observed. Kernel density estimates suggested a high degree of temporal overlap between the snow leopard and the fox, and the snow leopard and the lynx, as indicated by high overlap coefficient estimates. There is an opportunity to consider protective measures at the local scale that would benefit various species simultaneously. However, it should also be recognized that snow leopard conservation efforts could exacerbate human–wildlife conflicts through their protective effect on other carnivore species.
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Thomson, PC, K. Rose, and NE Kok. "The behavioural ecology of dingoes in north-western Australia. V. Population dynamics and variation in the soical system." Wildlife Research 19, no. 5 (1992): 565. http://dx.doi.org/10.1071/wr9920565.
Full textAbstract:
Between 1975 and 1984, 105 radio-collared dingoes, Canis familiaris dingo, were tracked and observed from aircraft on the Fortescue River in Western Australia. The majority of dingoes were members of 18 territorial packs, including four pairs. Five packs were monitored for more than three years. Most bitches became pregnant, including those 9-10 months old, although not all litters were raised. Packs raised an average of 1.1 litters per year. Instances of packs raising the litters of two bitches in a year were recorded. The area (up to 400km*2) was covered initially (1975-78) by a mosaic of stable pack territories. Little emigration occurred and population density rose to a peak of 22.2 dingoes per 100km*2 in 1978 due to an increase in pack size. Perturbations to the social system, including disintegration of some packs, an increase in emigration, shifts of pack territories and contraction of territories into the most favoured areas, coincided with high population density and a reduced food supply. After aerial baiting in 1980 killed all the dingoes from the study site, immigrants from surrounding areas established a new population. The increase in density was moderated by the formation of new pairs or packs that occupied surrounding vacant areas. The dispersal strategy of pack members was a major factor affecting the population density of dingoes in the study area.
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Stankov, Bojidar, Morten Møller, Valeria Lucini, Simona Capsoni, and Franco Fraschini. "A carnivore species (Canis familiaris) expresses circadian melatonin rhythm in the peripheral blood and melatonin receptors in the brain." European Journal of Endocrinology 131, no. 2 (August 1994): 191–200. http://dx.doi.org/10.1530/eje.0.1310191.
Full textAbstract:
Stankov B, Møller, M, Lucini V, Capsoni S, Fraschini F. A carnivore species (Canis familiaris) expresses circadian melatonin rhythm in the peripheral blood and melatonin receptors in the brain. Eur J Endocrinol 1994;131:191–200. ISSN 0804–4643 Dogs kept under controlled photoperiodic conditions of 12 h light and 12 h dark expressed a clear diurnal melatonin rhythm in the peripheral blood, with a swift peak restricted to the late part of the scotophase. The highest density of high-affinity, G-protein-linked 2-[125I]iodomelatonin binding sites was found in the pars tuberalis of the pituitary gland. Binding sites were found also in the pars distalis, and light microscopy/high-resolution autoradiography showed that binding was located exclusively over the chromophobe and basophilic cells forming the adenopituitary zona tuberalis, well developed in this species, and extending into the gland as a continuation of pars tuberalis. Cords of basophilic cells located in the pars distalis proper also expressed high receptor density. The eosinophils in the adenohypophysis and the neural lobe were devoid of binding. Heavily labeled were the external laminar and the mitral cell layers of the olfactory bulbs, but no binding was detected in the filae nervi olfactorii or tractus olfactorius. The hypothalamic suprachiasmatic nuclei were discernible clearly. Quantitative autoradiography inhibition experiments revealed that the apparent melatonin inhibitory constant (ic50) in all those areas was around 0.1 nmol/l, which is a physiologically appropriate value considering the peripheral blood melatonin levels. Co-incubation with guanosine 5′-O-(3-thiotriphosphate) (GTPΓS) led to a consequential decrease in the binding density. The specific binding observed in other areas (hippocampus, frontal, parietal, occipital cortex and cerebellum) was rather weak, diffuse and could not be attributed to a particular layer; the apparent ic50 for melatonin was about 1 μmol/l, and co-incubation with GTPΓS did not modify the binding density. Collectively, these data show that the dog posesses all the prerequisites for an efficient network adapted to photoperiodic time measurements. A circadian melatonin signal in the peripheral blood and an apparently functional readout receptor system located in key positions within the brain are both present in this species. Bojidar Stankov, Chair of Chemotherapy, Department of Pharmacology, University of Milan, 32 Via Vanvitelli, 20129 Milano, Italy
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Boothroyd, Simon, Andy Kerridge, Anders Broo, David Buttar, and Jamshed Anwar. "Solubility prediction from first principles: a density of states approach." Physical Chemistry Chemical Physics 20, no. 32 (2018): 20981–87. http://dx.doi.org/10.1039/c8cp01786g.
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Solubility is a fundamental property of widespread significance. Its accurate prediction remains a major challenge. We present a novel, efficient approach to solubility prediction for molecules over a range of conditions based on density of states.
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Shaltout, Kamal H., Ebrahem M. Eid, Yassin M. Al-Sodany, Selim Z. Heneidy, Salma K. Shaltout, and Safaa A. El-Masry. "Effect of Protection of Mountainous Vegetation against Over-Grazing and Over-Cutting in South Sinai, Egypt." Diversity 13, no. 3 (March 6, 2021): 113. http://dx.doi.org/10.3390/d13030113.
Full textAbstract:
In this study, we evaluated the species diversity, density, cover, and size index of plant species within and outside 37 enclosures in the South Sinai mountainous region (Egypt), which had been protected for six years (March 2012–March 2018) against over-grazing and over-cutting for medicinal and fuel purposes. Within and outside the enclosures, the plant species were recorded, and their density (individuals per 100 m2) and cover (cm per 100 cm) were estimated using the line-intercept method. The biovolume of each individual of each species was calculated as the average of its height and diameter. The species richness was calculated as the average number of species per enclosure, and the species turnover was calculated as the ratio between the total number of species and the species richness. The relative evenness was calculated using the Shannon–Weaver index, whereas the relative concentration of dominance was calculated using the Simpson index. Detrended correspondence analysis (DCA) was applied to ordinate the vegetation inside and outside the enclosures depending on the species cover. The unpaired t-test was applied to assess the statistically significant differences in the species density, cover, and biovolume inside and outside the enclosures. By the end of the six-year period, the vegetation pattern inside the enclosures became more or less stable, presumably because of the stopping of grazing and cutting, which also led to an increase in the plant diversity, density, and cover. In general, the protection of vegetation in South Sinai improved its diversity, density, and cover. In addition, the topographic and physiographic heterogeneity in this region results in microclimatic variations, which play a major role in governing its natural vegetation.
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Qureshi, I. R. "Positive gravity anomaly over the Sydney basin." Exploration Geophysics 20, no. 2 (1989): 191. http://dx.doi.org/10.1071/eg989191.
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A prominent positive gravity anomaly overlies the Macdonald trough in the Sydney basin. Allowing for isostatic compensation and the effect of sedimentary rocks, the anomaly is determined to have an amplitude of 440 GU (mms-2) and a width of 60 km. The anomaly is smoothed using cubic splines, FFT and IFFT. It is interpreted by a large mafic body of density 2.9 g cm-3 underlying the basin to a depth of 13.5 km. A 12 km wide zone with a small positive density contrast underlies the body within the lower crust.The steep western boundary of the body represents a major basement fault underlying the Lapstone monocline and Kurrajong Fault System.The anomaly is a member of the Meandarra Gravity Ridge which marks a zone of crustal extension within which dominant nature of intrusion is mafic in character.
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Ramkumaran, Kamaraj, Rethnaraj Chandran, Chowdula Satyanarayana, Kailash Chandra, and Tikadar Shyamal. "Density and obligatory feeding habits of an isolated Golden Jackal Canis aureus L. (Mammalia: Carnivora: Canidae) population in Pirotan Island, Gulf of Kachchh, India." Journal of Threatened Taxa 9, no. 4 (April 26, 2017): 10121. http://dx.doi.org/10.11609/jott.2988.9.4.10121-10124.
Full textAbstract:
Efforts to arrest the decline of carnivorous mammals in isolated ecosystems have received little attention in India. The present study assesses the population density of a small Golden Jackal population, isolated on a water covered Pirotan Island in the Gulf of Kachchh Marine National Park, India. An average of 12 Golden Jackals/km2 was found inhabiting the Island. The scat analysis revealed that the major diet of jackals was crab (89.5±2.36 %) followed by fish (2.7±0.82 %). Only 2.1% of their diets were from the Island source. They have well adapted to manage their water needs from their obligatory feeding habits.
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Bartel, Rebecca A., and Frederick F. Knowlton. "Functional feeding responses of coyotes, Canis latrans, to fluctuating prey abundance in the Curlew Valley, Utah, 1977–1993." Canadian Journal of Zoology 83, no. 4 (April 1, 2005): 569–78. http://dx.doi.org/10.1139/z05-039.
Full textAbstract:
We investigated interactions between coyotes (Canis latrans Say, 1823) and prey in the Curlew Valley, Utah, by comparing prey abundances with prey consumption rates. Previous studies reported a cyclic trend in black-tailed jackrabbit (Lepus californicus Gray, 1837) density with a period of 10 years and >150-fold amplitude, as well as short-term fluctuations among some rodent species that exceeded an 8-fold difference in amplitude over 2 years. Our results suggest changes in coyote diets mainly reflect the fluctuations in jackrabbit abundance. Prey switching to rodents during periods of low jackrabbit abundance also was evident. We used the initial feeding pattern analysis to compare prey consumption rates to prey abundance. Coyotes demonstrated a type II (hyperbolic) functional feeding response to changes in jackrabbit abundance. Functional feeding responses to rodent abundances were more difficult to assess because of the strong influence of jackrabbits. In most comparisons, we visually detected a linear functional feeding response to varying rodent abundances; yet this was not statistically supported by Akaike's Information Criterion corrected for small sample sizes (AICc) to assess different models.
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Gerber, Brian, Sarah M. Karpanty, Charles Crawford, Mary Kotschwar, and Johnny Randrianantenaina. "An assessment of carnivore relative abundance and density in the eastern rainforests of Madagascar using remotely-triggered camera traps." Oryx 44, no. 2 (January 12, 2010): 219–22. http://dx.doi.org/10.1017/s0030605309991037.
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AbstractDespite major efforts to understand and conserve Madagascar’s unique biodiversity, relatively little is known about the island’s carnivore populations. We therefore deployed 43 camera-trap stations in Ranomafana National Park, Madagascar during June–August 2007 to evaluate the efficacy of this method for studying Malagasy carnivores and to estimate the relative abundance and density of carnivores in the eastern rainforest. A total of 755 camera-trap nights provided 1,605 photographs of four endemic carnivore species (fossa Cryptoprocta ferox, Malagasy civet Fossa fossana, ring-tailed mongoose Galidia elegans and broad-striped mongoose Galidictus fasciata), the exotic Indian civet Viverricula indica and the domestic dog Canis familiaris. We identified 38 individual F. fossana and 10 individual C. ferox. We estimated density using both capture-recapture analyses, with a buffer of full mean-maximum-distance-moved, and a spatially-explicit maximum-likelihood method (F. fossana: 3.03 and 2.23 km-2, respectively; C. ferox: 0.15 and 0.17 km-2, respectively). Our estimated densities of C. ferox in rainforest are lower than published estimates for conspecifics in the western dry forests. Within Ranomafana National Park species richness of native carnivores did not vary among trail systems located in secondary, selectively-logged and undisturbed forest. These results provide the first assessment of carnivore population parameters using camera-traps in the eastern rainforests of Madagascar.
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Pople, A. R., G. C. Grigg, S. C. Cairns, L. A. Beard, and P. Alexander. "Trends in the numbers of red kangaroos and emus on either side of the South Australian dingo fence: evidence for predator regulation?" Wildlife Research 27, no. 3 (2000): 269. http://dx.doi.org/10.1071/wr99030.
Full textAbstract:
Most of Australia’s sheep rangelands are enclosed by a dingo-proof fence. Within these rangelands, where dingoes (Canis lupus dingo) are rare, red kangaroos (Macropus rufus) are considered to be food limited because their numbers respond to fluctuations in pasture biomass that are driven by highly variable rainfall. Outside this region, where dingoes are common, kangaroo densities are generally substantially lower, suggesting that dingoes are an important limiting factor. However, it is unclear whether dingoes can regulate kangaroo populations. In this study, red kangaroo and emu (Dromaius novaehollandiae) numbers were monitored for varying periods during 1978–92 by aerial survey on both sides of the dingo fence in three areas in the north of the South Australian pastoral zone. Densities of red kangaroos and emus were lower outside the fence, although the disparity varied between areas and over time. The similarity in the environments on both sides of the fence and the marked step in kangaroo density at the fence are consistent with dingoes strongly limiting these prey populations. In the north-east of the pastoral zone, where kangaroo and emu densities are greatest, the contrast in density across the fence was most pronounced. Furthermore, the trends in density over time differed across the fence. Outside the fence, red kangaroos and emus remained at low densities following drought as dingo numbers increased. Inside the fence, red kangaroo and emu populations showed a ‘typical’ post-drought recovery. The data therefore suggest that, in some situations, dingoes may not simply limit red kangaroo and emu populations, but also regulate them. For this to occur, predation rate would need to be density dependent at low prey densities. The availability of alternative prey, and the reduction in the numbers of all prey during drought may provide the mechanism.
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Athreya, Vidya, Morten Odden, John D. C. Linnell, Jagdish Krishnaswamy, and K. Ullas Karanth. "A cat among the dogs: leopard Panthera pardus diet in a human-dominated landscape in western Maharashtra, India." Oryx 50, no. 1 (September 11, 2014): 156–62. http://dx.doi.org/10.1017/s0030605314000106.
Full textAbstract:
AbstractThe ecology and predator–prey dynamics of large felids in the tropics have largely been studied in natural systems where wild ungulates constitute the majority of the prey base. However, human-dominated landscapes can be rich in potential prey for large carnivores because of the high density of domestic animals, especially in tropical countries where pastoralism is an important livelihood activity. We report the almost complete dependence of leopards Panthera pardus on domestic animals as prey in the crop lands of Ahmednagar district, Maharashtra, India. From analysis of 85 confirmed leopard scats, 87% of the leopard's prey biomass consisted of domestic animals, with 39% consisting of domestic dogs Canis lupus familiaris alone. The only wild species that occurred in the leopard's diet were rodents, small indian civet Viverricula indica, bonnet macaque Macaca radiata and other primates Semnopithecus spp., mongoose Herpestes spp., and birds. Interviews conducted in 77 households distributed randomly in the study area documented a high density of domestic animals: adult cattle Bos taurus, calves, goats Capra aegagrus, dogs and cats Felis catus occurred at densities of 169, 54, 174, 24 and 61 per km2, respectively. Ivlev's electivity index indicated that dogs and cats were over-represented in the leopard's diet, given the higher densities of goats and cattle. The standing biomass of dogs and cats alone was sufficient to sustain the high density of carnivores at the study site. Our results show that the abundance of potential domestic prey biomass present in human-use areas supports a relatively high density of predators, although this interaction could result in conflict with humans.
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Reverter, B. R., E. P. Sánchez-Cañete, V. Resco, P. Serrano-Ortiz, C. Oyonarte, and A. S. Kowalski. "Analyzing the major drivers of NEE in a Mediterranean alpine shrubland." Biogeosciences 7, no. 9 (September 3, 2010): 2601–11. http://dx.doi.org/10.5194/bg-7-2601-2010.
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Abstract. Two years of continuous measurements of net ecosystem exchange (NEE) using the eddy covariance technique were made over a Mediterranean alpine shrubland. This ecosystem was found to be a net source of CO2 (+ 52 ± 7 g C m−2 and + 48 ± 7 g C m−2 for 2007 and 2008) during the two-year study period. To understand the reasons underlying this net release of CO2 into the atmosphere, we analysed the drivers of seasonal variability in NEE over these two years. We observed that the soil water availability – driven by the precipitation pattern – and the photosynthetic photon flux density (PPFD) are the key factors for understanding both the carbon sequestration potential and the duration of the photosynthetic period during the growing season. Finally, the effects of the self-heating correction to CO2 and H2O fluxes measured with the open-path infrared gas analyser were evaluated. Applying the correction turned the annual CO2 budget in 2007 from a sink (− 135 ± 7 g C m−2) to a source (+ 52 ± 7 g C m−2). The magnitude of this change is larger than reported previously and is shown to be due to the low air density and cold temperatures at this high elevation study site.
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Zanzani, Sergio Aurelio, Anna Rita Di Cerbo, Alessia Libera Gazzonis, Marco Genchi, Laura Rinaldi, Vincenzo Musella, Giuseppe Cringoli, and Maria Teresa Manfredi. "Canine Fecal Contamination in a Metropolitan Area (Milan, North-Western Italy): Prevalence of Intestinal Parasites and Evaluation of Health Risks." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/132361.
Full textAbstract:
Intestinal parasites of dogs represent a serious threat to human health due to their zoonotic potential. Thus, metropolitan areas presenting high concentrations of pets and urban fecal contamination on public areas are at sanitary risk. Major aim of this survey was to determine prevalence of zoonotic parasites in dog fecal samples collected from public soil of Milan (north-western Italy). Differences in parasites prevalence distribution were explored by a geographical information system- (GIS-) based approach, and risk factors (human density, sizes of green parks, and dog areas) were considered. The metropolitan area was divided into 157 rectangular subareas and sampling was performed following a 1-kilometer straight transect. A total of 463 fecal samples were analyzed using centrifugation-flotation technique and ELISA to detectGiardiaandCryptosporidiumcoproantigens. A widespread fecal contamination of soil was highlighted, being fecal samples found in 86.8% of the subareas considered. The overall prevalence of intestinal parasites was 16.63%. Zoonotic parasites were found, such asTrichuris vulpis(3.67%),Toxocara canis(1.72%),Strongyloides stercoralis(0.86%), Ancylostomatidae (0.43%), andDipylidium caninum(0.43%).Giardia duodenaliswas the most prevalent zoonotic protozoa (11.06%), followed byCryptosporidium(1.10%). Faeces from subareas characterized by broad green areas showed to be particularly prone to infection.
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Spencer, T. W., and H. C. Chi. "Thin‐layer fracture density." GEOPHYSICS 56, no. 6 (June 1991): 833–43. http://dx.doi.org/10.1190/1.1443101.
Full textAbstract:
Vertically propagating shear waves reflected from a thin reservoir permeated by a single oriented system of open vertical fractures contain information about the fracture density. The outer perimeter of the hodogram constructed from shear waves polarized in the fast and slow directions in the natural coordinate system is approximately elliptical. The polarization is defined as the angle which the major axis of the ellipse makes with the natural coordinate. Over a range of layer thickness which extends well above and below the tuning frequency, the polarization does not deviate from its value for an infinitely thick layer, [Formula: see text], by more than a few degrees. [Formula: see text] and [Formula: see text] are the reflection coefficients in the fast and slow directions. [Formula: see text] is independent of the fracture density, but ψ, [Formula: see text], and the anisotropy η all depend on the fracture density. [Formula: see text], [Formula: see text], and η are related by [Formula: see text]. Analysis of the constant‐anisotropy hyperbolas derived from this equation reveals conditions under which ψ is extremely sensitive to variations in anisotropy. As η increases by 20 percent, the change in ψ approaches 135 degrees for small negative [Formula: see text] and 45 degrees for small positive [Formula: see text]. The ellipse is also characterized by an aspect ratio which is significantly different from zero over a range of layer thickness that extends above and below the tuning frequency. Aspect ratio versus polarization (ARP) curves can be constructed from multi component field data. Each curve is constructed for fixed [Formula: see text] and [Formula: see text] (the two‐way traveltime across the layer for the fast polarization). [Formula: see text] and [Formula: see text] are independent of lateral changes in fracture density. Consequently, points on ARP curves correspond to different values of the anisotropy. If [Formula: see text] is known from well measurements, [Formula: see text] can be determined and a value of anisotropy assigned to each point where there is a field measurement.
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Day, W. R., and P. F. Lee. "Ecological relationships of wild rice, Zizania aquatica. 8. Classification of sediments." Canadian Journal of Botany 67, no. 5 (May 1, 1989): 1381–86. http://dx.doi.org/10.1139/b89-182.
Full textAbstract:
Cluster and discriminant analysis classified sediments from potential and existing wild rice lakes into three major and three hybrid types. The three major sediment types were described as clay, organic, or flocculent, and the three hybrid types as organic – flocculent, organic – clay, or organic over clay. The major differences among the six sediment types were the percent loss-on-ignition, bulk density, phosphorus, cation, and pH values. Organic sediments were characterized by high phosphorus, cation, and loss-on-ignition values, and lower pH values. Clay sediments had the highest bulk density values, but were low in phosphorus. Flocculent sediments exhibited the lowest bulk density, phosphorus, and cation values, and the highest loss-on-ignition and pH values. The three hybrid sediment types had values for these variables intermediate to their parent types. Flocculent, clay, and organic–flocculent sediment types produced the lowest dry weights of individual wild rice plants. Best production (in terms of dry weight) occurred in organic, organic–clay, and organic over clay sediments that had loss-on-ignition values ranging from 29 to 49%, were slightly acidic (pH values of 5.9 −6.2), and had high phosphorus (> 1.0 g ∙ m−2) and cation values.
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Radojicic, Sonja. "Canine brucellosis: Epizootiological characteristics, therapy and control of the disease." Veterinarski glasnik 60, no. 3-4 (2006): 135–45. http://dx.doi.org/10.2298/vetgl0604135r.
Full textAbstract:
The paper describes different aspects of canine brucellosis caused by Brucella canis. The disease is present in a large number of countries all over the world, where it inflicts severe economic damages, in particular in the commercial breeding and major dog breeding facilities. The disease was discovered in 1966 in the United States of America, but there were no data about its presence or distribution in our country until 1999. It was established, following the initial investigations, that the prevalence of the disease is extremely high, and that it amounted to 4.27% among pet dogs in the territory of Belgrade. Investigations of stray dogs in the territory of Podgorica showed that the seroprevalence (an equal titer or higher than 1/200) was 9.37%, while the prevalence among stray dogs in the territory of Belgrade was 10.87%. Data for other parts of Serbia are mostly lacking, and the seroprevalence for stray dogs in the Municipality of Pozarevac amounted to over 15%, while not a single serologically positive case was found among pet dogs. In addition to the epizootiological specificities of the disease established in our country, isolates of B. canis from the territory of Serbia also indicate digressions in the test of resistance to colors with respect to the referent strain RM6/66. All isolates (SR1-SR-7) are resistant to base fuchsine, and it is probable that this characteristic could also be an important epizootiological marker. Even though the isolation of the cause is the most reliable diagnostic method, it is not possible to achieve this in most cases. That is why one of the most important tasks is to define the most ideal tests for the serological diagnostics of the disease, and the obligation of reporting the disease makes it imperative that wider-scale investigations are conducted and that measures are taken toward reducing the number of positive cases in our country. .
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Palmqvist, Paul, Bienvenido Martínez-Navarro, and Alfonso Arribas. "Prey selection by terrestrial carnivores in a lower Pleistocene paleocommunity." Paleobiology 22, no. 4 (1996): 514–34. http://dx.doi.org/10.1017/s009483730001650x.
Full textAbstract:
We report quantitative paleoecologic data on the large mammal assemblage preserved in lower Pleistocene deposits at Venta Micena (Orce, Granada, southeastern Spain). Taphonomic studies show that bones were collected mainly by hyaenids, which transported and deposited them near shallow dens. Differential fragmentation of major long bones was produced by hyaenas as a function of their density and marrow content. Strong selection of prey by carnivores—which preferentially killed juveniles, females, and individuals with diminished locomotor capabilities among ungulate prey species of larger body size—is indicated by (1) the abundance of remains of juvenile ungulates in relation to the average weight of adult individuals in each species, (2) attritional mortality profiles for ungulate species deduced from crown height measurements, (3) the presence of many metapodials with different osteopathologies in their epiphyses, such as arthrosis, and (4) a biased intersexual ratio of large bovids. Comparison of the frequencies with which modern African carnivores kill and scavenge ungulates from various size classes with the abundance of these size categories in the assemblage suggests that the Venta Micena hyaena (Pachycrocuta brevirostris) was a bone-cracking scavenger that fed largely on carcasses of ungulates preyed upon and partially consumed by fresh meat-eating carnivores such us saber-toothed felids (Homotherium latidens and Megantereon whitei) and wild dogs (Canis falconeri).
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Kryder, Mark H. "Ultrahigh-Density Recording Technologies." MRS Bulletin 21, no. 9 (September 1996): 17–22. http://dx.doi.org/10.1557/s0883769400036319.
Full textAbstract:
Magnetic recording and optical recording are the major technologies used to provide long-term storage of information in today's computer systems. Magnetic recording has been used for data storage in computer systems for over 40 years, and the advances in technology that have occurred in that time frame are nothing short of phenomenal. One might expect that after 40 years of dominance, the rate of progress in magnetic recording would be slowing down and that other technologies would be moving in to replace it. However rather than slowing down its rate of progress, magnetic recording is now advancing at a faster rate than at any time in the past. Magnetic hard-disk drives represent the largest segment of the data-storage business, and the number of hard-disk drives sold is increasing at about 20% per year. Tape drives continue to enjoy a very substantial market and are also advancing at a rapid pace while flexible disk drives continue to appear in every personal computer sold and have recently increased capacity by nearly two orders of magnitude.Optical recording was introduced into the marketplace in 1989 and has secured a significant market. However thus far, optical recording has primarily found new market niches, rather than being directly competitive with magnetic recording. CD-ROMs are widely used for the distribution of prerecorded information—a business that is now comparable in size to the magnetic-tape-drive business. On the other hand, erasable, optical drives, which were first introduced in 1989, have not had nearly as much success and have much smaller markets than either magnetic hard drives or tape drives.
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Richier, Eric, Giancarlo A. Biagini, Sharon Wein, Frederic Boudou, Patrick G. Bray, Steve A. Ward, Eric Precigout, Michèle Calas, Jean-François Dubremetz, and Henri J. Vial. "Potent Antihematozoan Activity of Novel Bisthiazolium Drug T16: Evidence for Inhibition of Phosphatidylcholine Metabolism in Erythrocytes Infected with Babesia and Plasmodium spp." Antimicrobial Agents and Chemotherapy 50, no. 10 (October 2006): 3381–88. http://dx.doi.org/10.1128/aac.00443-06.
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ABSTRACT A leading bisthiazolium drug, T16, designed to mimic choline, was shown to exert potent antibabesial activity, with 50% inhibitory concentrations of 28 and 7 nM against Babesia divergens and B. canis, respectively. T16 accumulated inside Babesia-infected erythrocytes (cellular accumulation ratio, >60) by a saturable process with an apparent Km of 0.65 μM. Subcellular fractionation of Babesia parasites revealed the accumulation of T16 into a low-density fraction, while in malaria-infected erythrocytes a significant fraction of the drug was associated with heme malaria pigment. T16 exerts an early and specific inhibition of the de novo biosynthesis of phosphatidylcholine both in B. divergens- and Plasmodium falciparum-infected erythrocytes. Choline accumulation into isolated Babesia parasites was highly sensitive to inhibition by T16. These data are consistent with the hypothesis that bisthiazolium drugs target the de novo phosphatidylcholine biosynthesis of intraerythrocytic hematozoan parasites. In malaria parasites, which generate ferriprotoporphyrin IX during hemoglobin digestion, T16 binding to heme may enhance the accumulation and activity of the drug. The selectivity of accumulation and potent activity of this class of drug into parasite-infected erythrocytes offers unique advantages over more traditional antihematozoan drugs.
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Abdulhamid, Mohanad F., and Onyango Ben Sewe. "Performance of UWB-WBAN System Over Awgn Channel." Technological Engineering 15, no. 1 (October 1, 2018): 20–25. http://dx.doi.org/10.1515/teen-2018-0004.
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Abstract The major constraints in the design of Wireless Body Area Network(WBAN) can be attributed to the battery autonomy, need for high data rate services and low interference from the devices operating within the industrial, scientific and medical (ISM) bands. To meet the demand for high data rate services and low power spectral density to avoid ISM band interference, an ultra-wide band(UWB) system based technology has been proposed. This paper focuses on the design and demonstration of an UWB modem to be used in the WBAN applications and the evaluation of its performance in a near-real world scenarios affected by additive white Gaussian noise(AWGN) interference. The modem is tested with different values of signal to noise ratio(SNR). Results show that the performance of the modem degrades as the value of SNR decreases.
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Woinarski, John C. Z., Sally L. South, Paul Drummond, Gregory R. Johnston, and Alex Nankivell. "The diet of the feral cat (Felis catus), red fox (Vulpes vulpes) and dog (Canis familiaris) over a three-year period at Witchelina Reserve, in arid South Australia." Australian Mammalogy 40, no. 2 (2018): 204. http://dx.doi.org/10.1071/am17033.
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Introduced predators have had, and continue to have, severe impacts on Australian biodiversity. At a recently established conservation reserve, Witchelina, in arid South Australia, we assessed the diet of feral cats (Felis catus) (404 samples), red fox (Vulpes vulpes) (51 samples) and dog (Canis familiaris) (11 samples) over a 3-year period. There was marked overlap (98.5%) in dietary composition between cats and foxes. Rabbits (Oryctolagus cuniculus) comprised a major dietary item for all three predators. Invertebrates contributed the largest number of prey items for foxes and cats, but mammals comprised the bulk, by weight, for all three predators. Birds and reptiles had a higher frequency of occurrence in the diet of cats than of foxes or dogs. The size of mammal prey taken was least for cats and greatest for dogs. The diets of cats and foxes showed significant seasonal variation, with reptiles and invertebrates being least common in the diet in winter. The threatened thick-billed grasswren (Amytornis modestus) was found for the first time in the diet of feral cats. Bearded dragons (Pogona vitticeps) occurred in about one-third of cat and fox samples. This study contributes further to the evidence of biodiversity impacts of introduced predators, and the need for their strategic management.
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Kobeni, Sibusiso, Gernot Osthoff, Moses Madende, Arnold Hugo, and Lisa Marabini. "The Dynamic Changes of African Elephant Milk Composition over Lactation." Animals 10, no. 6 (May 30, 2020): 948. http://dx.doi.org/10.3390/ani10060948.
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The combined data of milk composition of 14 African elephants over 25 months of lactation are presented. The milk density was constant during lactation. The total protein content increased with progressing lactation, with caseins as the predominant protein fraction. The total carbohydrates steadily decreased, with the oligosaccharides becoming the major fraction. Lactose and isoglobotriose reached equal levels at mid lactation. The milk fat content increased during lactation, as did the caprylic and capric acids, while the 12 carbon and longer fatty acids decreased. The fatty acid composition of the milk phospholipids fluctuated, and their total saturated fatty acid composition was low compared to the triacylglycerides. The milk ash and content of the major minerals, Na, K, Mg, P, and Ca, increased. Vitamin content was low, Vitamin E occurred in quantifiable amounts, with traces of vitamins A, D3, and K. The energy levels of African elephant milk did not change much in the first ten months of lactation, but they increased thereafter due to the increase in protein and fat content. The overall changes in milk composition appeared to be in two stages: (a) strong changes up to approximately 12 months of lactation and (b) little or no changes thereafter.
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Zhou, Shijie, Andre E. Punt, Roy Deng, Marco Kienzle, and Wayne Rochester. "Bayesian fishable biomass dynamics models incorporating fished area and relative fish density." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 9 (September 2011): 1603–14. http://dx.doi.org/10.1139/f2011-083.
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Fisheries typically experience large changes over time in fishing effort. The size of the area fished may also change substantially over time, mimicking the trend in fishing effort, and may have major effects on the population dynamics and fishing process. We extend a biomass dynamics model to incorporate fished area and relative fish density in fished and unfished areas. The fishable population is defined as those individuals in the fished area and those that are sufficiently close to the fished area that they could potentially move into fished area during the fishing season. We estimate fishable biomass using three models assuming different level of population mixing between fished and unfished areas (i.e., partial mixing, full mixing, and no mixing). The models are implemented within a hierarchical Bayesian framework. Model performance is explored using simulations, and the approach is illustrated using logbook data for two tiger prawn species in Australia’s Northern Prawn Fishery. The partial mixing model that involves estimating a mixing parameter performs better than the models that assume no or full mixing. The methods could be applied to other fisheries where the area fished has changed substantially over the history of the fishery.
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Chazdon, Robin L., Susan G. Letcher, Michiel van Breugel, Miguel Martínez-Ramos, Frans Bongers, and Bryan Finegan. "Rates of change in tree communities of secondary Neotropical forests following major disturbances." Philosophical Transactions of the Royal Society B: Biological Sciences 362, no. 1478 (December 19, 2006): 273–89. http://dx.doi.org/10.1098/rstb.2006.1990.
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Rates of change in tree communities following major disturbances are determined by a complex set of interactions between local site factors, landscape history and structure, regional species pools and species life histories. Our analysis focuses on vegetation change following abandonment of agricultural fields or pastures, as this is the most extensive form of major disturbance in Neotropical forests. We consider five tree community attributes: stem density, basal area, species density, species richness and species composition. We describe two case studies, in northeastern Costa Rica and Chiapas, Mexico, where both chronosequence and annual tree dynamics studies are being applied. These case studies show that the rates of change in tree communities often deviate from chronosequence trends. With respect to tree species composition, sites of different ages differ more than a single site followed over time through the same age range. Dynamic changes in basal area within stands, on the other hand, generally followed chronosequence trends. Basal area accumulation was more linked with tree growth rates than with net changes in tree density due to recruitment and mortality. Stem turnover rates were poor predictors of species turnover rates, particularly at longer time-intervals. Effects of the surrounding landscape on tree community dynamics within individual plots are poorly understood, but are likely to be important determinants of species accumulation rates and relative abundance patterns.
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Yahil, Amos. "Contributions to the Local Gravitational Field from Beyond the Virgo Supercluster." Symposium - International Astronomical Union 124 (1987): 247–50. http://dx.doi.org/10.1017/s0074180900159200.
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In the last decade, the inter-relation between the density structure and velocity perturbations in the local Virgo Supercluster (VSC) has provided a major means of determining the cosmological density parameter Ωo. The underlying dynamics, the so-called Virgocentric Flow Model (VFM), assumes that the relevant peculiar gravitational field in the VSC is dominated by the monopole term, due to material inside the VSC. Over the past year, however, this premise has been called into question, on both observational and theoretical grounds. It has become clear that the contributions to the local gravitational field from beyond the VSC cannot be neglected. The major new developments are summarized here. A more detailed review is given elsewhere (Yahil 1987).
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Widyastiti, Nyoman Suci, and I. Edward Kurnia Setiawan Limijadi. "Pemeriksaan Bone Mineral Density dan Pelatihan Senam Osteoporosis Sebagai Upaya Peningkatan Kewaspadaan Osteoporosis pada Penderita Talasemia Mayor." Journal of Dedicators Community 5, no. 2 (July 27, 2020): 138–47. http://dx.doi.org/10.34001/jdc.v5i2.1348.
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Thalassemia major patients with routine transfusions are at risk of experiencing iron overload and bone turn over disorders which will increase the risk of osteoporosis. Community training activities with BMD examinations and osteoporosis exercise training in thalassemia major patients are expected to identify the prevalence of bone fragility in thalassemia major patients, increase the awareness of thalassemia major patients and their families to the risk of osteoporosis in thalassemia major patients and osteoporosis exercise training as an effort to prevent osteroporosis. The results of BMD on the spine showed 57.1% osteoporosis, 28.6% normal and 14.3% osteopenia. The results of BMD examination on the cervical spine showed 71.4% osteopenia, 21.4% normal and 7.2% osteoporosis. The results of BMD examination on the femur found 50% normal, 42.8% osteopenia and 7.2% osteoporosis. The bone location with the highest percentage of osteoporosis was the spine (57%), and the bone location with the highest percentage of osteopenia was the neck bone (71.4%). The high percentage of osteopenia locations in the cervical spine of thalassemia major patients with repeated transfusions should be become a concern. Based on these findings, we held education and counselling on the risk of osteoporosis in thalassemia patients with repeated transfusions, osteoporosis exercise training and distribution of osteoporosis exercise compact disk (CD) for at home osteoporosis exercise training.
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Guan, Xiaodan, Jianping Huang, Yanting Zhang, Yongkun Xie, and Jingjing Liu. "The relationship between anthropogenic dust and population over global semi-arid regions." Atmospheric Chemistry and Physics 16, no. 8 (April 25, 2016): 5159–69. http://dx.doi.org/10.5194/acp-16-5159-2016.
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Abstract. Although anthropogenic dust has received more attention from the climate research community, its dominant role in the production process is still not identified. In this study, we analysed the relationship between anthropogenic dust and population density/change over global semi-arid regions and found that semi-arid regions are major source regions in producing anthropogenic dust. The results showed that the relationship between anthropogenic dust and population is more obvious in cropland than in other land cover types (crop mosaics, grassland, and urbanized regions) and that the production of anthropogenic dust increases as the population density grows to more than 90 persons km−2. Four selected semi-arid regions, namely East China, India, North America, and North Africa, were used to explore the relationship between anthropogenic dust production and regional population. The most significant relationship between anthropogenic dust and population occurred in an Indian semi-arid region that had a greater portion of cropland, and the high peak of anthropogenic dust probability appeared with 220 persons km−2 of population density and 60 persons km−2 of population change. These results suggest that the influence of population on production of anthropogenic dust in semi-arid regions is obvious in cropland regions. However, the impact does not always have a positive contribution to the production of anthropogenic dust, and overly excessive population will suppress the increase of anthropogenic dust. Moreover, radiative and climate effects of increasing anthropogenic dust need more investigation.
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Teknik, Vahid, Abdolreza Ghods, Hans Thybo, and Irina M. Artemieva. "Crustal density structure of the northwestern Iranian Plateau." Canadian Journal of Earth Sciences 56, no. 12 (December 2019): 1347–65. http://dx.doi.org/10.1139/cjes-2018-0232.
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We present a new 2D crustal-scale model of the northwestern Iranian plateau based on gravity–magnetic modeling along the 500 km long China–Iran Geological and Geophysical Survey in the Iranian plateau (CIGSIP) seismic profile across major tectonic provinces of Iran from the Arabian plate into the South Caspian Basin (SCB). The seismic P-wave receiver function (RF) model along the profile is used to constrain major crustal boundaries in the density model. Our 2D crustal model shows significant variation in the sedimentary thickness, Moho depth, and the depth and extent of intra-crustal interfaces. The Main Recent Fault (MRF) between the Arabian crust and the overriding central Iran crust dips at approximately 13° towards the northeast to a depth of about 40 km. The geometry of the MRF suggests about 150 km of underthrusting of the Arabian plate beneath central Iran. Our results indicate the presence of a high-density lower crustal layer beneath Zagros. We identify a new crustal-scale suture beneath the Tarom valley between the South Caspian Basin crust and Central Iran and the Alborz. This suture is associated with sharp variation in Moho depth, topography, and magnetic anomalies, and is underlain by a 20 km thick high-density crustal root at 35–55 km depth. The high-density lower crust in Alborz and Zagros may be related to partial eclogitization of crustal roots below about 40 km depth. The gravity and magnetic models indicate a highly extended continental crust for the SCB crust along the profile. Low observed magnetic susceptibility of the Kermanshah ophiolites likely indicates that the ophiolite rocks only form a thin layer that has been thrust over the sedimentary cover.