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Sample records for density host age

  1. Wolbachia age-sex-specific density in Aedes albopictus: a host evolutionary response to cytoplasmic incompatibility?

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    Pablo Tortosa

    2010-03-01

    Full Text Available Wolbachia bacteria have invaded many arthropod species by inducing Cytoplasmic Incompatibility (CI. These symbionts represent fascinating objects of study for evolutionary biologists, but also powerful potential biocontrol agents. Here, we assess the density dynamics of Wolbachia infections in males and females of the mosquito Aedes albopitcus, an important vector of human pathogens, and interpret the results within an evolutionary framework.Wolbachia densities were measured in natural populations and in age controlled mosquitoes using quantitative PCR. We show that the density dynamics of the wAlbA Wolbachia strain infecting Aedes albopictus drastically differ between males and females, with a very rapid decay of infection in males only.Theory predicts that Wolbachia and its hosts should cooperate to improve the transmission of infection to offspring, because only infected eggs are protected from the effects of CI. However, incompatible matings effectively lower the fertility of infected males, so that selection acting on the host genome should tend to reduce the expression of CI in males, for example, by reducing infection density in males before sexual maturation. The rapid decay of one Wolbachia infection in Aedes albopictus males, but not in females, is consistent with this prediction. We suggest that the commonly observed reduction in CI intensity with male age reflects a similar evolutionary process. Our results also highlight the importance of monitoring infection density dynamics in both males and females to assess the efficiency of Wolbachia-based control strategies.

  2. Host age modulates within-host parasite competition.

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    Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

    2015-05-01

    In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, age-dependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  3. Host density and competency determine the effects of host diversity on trematode parasite infection.

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    Jeremy M Wojdak

    Full Text Available Variation in host species composition can dramatically alter parasite transmission in natural communities. Whether diverse host communities dilute or amplify parasite transmission is thought to depend critically on species traits, particularly on how hosts affect each other's densities, and their relative competency as hosts. Here we studied a community of potential hosts and/or decoys (i.e. non-competent hosts for two trematode parasite species, Echinostoma trivolvis and Ribeiroia ondatrae, which commonly infect wildlife across North America. We manipulated the density of a focal host (green frog tadpoles, Rana clamitans, in concert with manipulating the diversity of alternative species, to simulate communities where alternative species either (1 replace the focal host species so that the total number of individuals remains constant (substitution or (2 add to total host density (addition. For E. trivolvis, we found that total parasite transmission remained roughly equal (or perhaps decreased slightly when alternative species replaced focal host individuals, but parasite transmission was higher when alternative species were added to a community without replacing focal host individuals. Given the alternative species were roughly equal in competency, these results are consistent with current theory. Remarkably, both total tadpole and per-capita tadpole infection intensity by E. trivolvis increased with increasing intraspecific host density. For R. ondatrae, alternative species did not function as effective decoys or hosts for parasite infective stages, and the diversity and density treatments did not produce clear changes in parasite transmission, although high tank to tank variation in R. ondatrae infection could have obscured patterns.

  4. Host density increases parasite recruitment but decreases host risk in a snail-trematode system.

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    Buck, J C; Hechinger, R F; Wood, A C; Stewart, T E; Kuris, A M; Lafferty, K D

    2017-08-01

    Most species aggregate in local patches. High host density in patches increases contact rate between hosts and parasites, increasing parasite transmission success. At the same time, for environmentally transmitted parasites, high host density can decrease infection risk to individual hosts, because infective stages are divided among all hosts in a patch, leading to safety in numbers. We tested these predictions using the California horn snail, Cerithideopsis californica (=Cerithidea californica), which is the first intermediate host for at least 19 digenean trematode species in California estuaries. Snails become infected by ingesting trematode eggs or through penetration by free-swimming miracidia that hatch from trematode eggs deposited with final-host (bird or mammal) feces. This complex life cycle decouples infective-stage production from transmission, raising the possibility of an inverse relationship between host density and infection risk at local scales. In a field survey, higher snail density was associated with increased trematode (infected snail) density, but decreased trematode prevalence, consistent with either safety in numbers, parasitic castration, or both. To determine the extent to which safety in numbers drove the negative snail-density-trematode-prevalence association, we manipulated uninfected snail density in 83 cages at eight sites within Carpinteria Salt Marsh (California, USA). At each site, we quantified snail density and used data on final-host (bird and raccoon) distributions to control for between-site variation in infective-stage supply. After three months, overall trematode infections per cage increased with snail biomass density. For egg-transmitted trematodes, per-snail infection risk decreased with snail biomass density in the cage and surrounding area, whereas per-snail infection risk did not decrease for miracidium-transmitted trematodes. Furthermore, both trematode recruitment and infection risk increased with infective

  5. Host age modulates parasite infectivity, virulence and reproduction.

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    Izhar, Rony; Ben-Ami, Frida

    2015-07-01

    Host age is one of the most striking differences among hosts within most populations, but there is very little data on how age-dependent effects impact ecological and evolutionary dynamics of both the host and the parasite. Here, we examined the influence of host age (juveniles, young and old adults) at parasite exposure on host susceptibility, fecundity and survival as well as parasite transmission, using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa. Younger D. magna were more susceptible to infection than older ones, regardless of host or parasite clone. Also, younger-infected D. magna became castrated faster than older hosts, but host and parasite clone effects contributed to this trait as well. Furthermore, the early-infected D. magna produced considerably more parasite transmission stages than late-infected ones, while host age at exposure did not affect virulence as it is defined in models (host mortality). When virulence is defined more broadly as the negative effects of infection on host fitness, by integrating the parasitic effects on host fecundity and mortality, then host age at exposure seems to slide along a negative relationship between host and parasite fitness. Thus, the virulence-transmission trade-off differs strongly among age classes, which in turn affects predictions of optimal virulence. Age-dependent effects on host susceptibility, virulence and parasite transmission could pose an important challenge for experimental and theoretical studies of infectious disease dynamics and disease ecology. Our results present a call for a more explicit stage-structured theory for disease, which will incorporate age-dependent epidemiological parameters. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  6. Limited by the host: Host age hampers establishment of holoparasite Cuscuta epithymum

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    Meulebrouck, Klaar; Verheyen, Kris; Brys, Rein; Hermy, Martin

    2009-07-01

    A good understanding of the relationship between plant establishment and the ecosystem of which they are part of is needed to conserve rare plant species. Introduction experiments offer a direct test of recruitment limitation, but generally only the seed germination and seedling phases are monitored. Thus the relative importance of different establishment stages in the process of recruitment is not considered. This is particularly true for parasitic plants where empirical data are generally missing. During two consecutive growing seasons we examined the effect of heathland management applications, degree of heathland succession (pioneer, building and mature phase) and seed-density on the recruitment and establishment of the endangered holoparasite Cuscuta epithymum. In general, recruitment after two growing seasons was low with 4.79% of the sown seeds that successfully emerged to the seedling stage and a final establishment of 89 flowering adults (i.e. <1.5% of the sown seeds). Although a higher seed-density resulted in a higher number of seedlings, seed-density did not significantly affected relative germination percentages. The management type and subsequent heath succession had no significant effect on seedling emergence; whereas, seedling attachment to the host, establishment and growth to full-grown size were hampered in older heath vegetation (i.e. high, dense, and mature canopy). Establishment was most successful in turf-cut pioneer heathland, characterised by a relatively open and low vegetation of young Calluna vulgaris. The age of C. vulgaris, C. epithymum's main host, proved to be the most limiting factor. These results emphasise the importance of site quality (i.e. successional phase of its host) on recruitment success of C. epithymum, which is directly affected by the management applied to the vegetation. Lack of any heathland management will thus seriously restrict establishment of the endangered parasite.

  7. Departure mechanisms for host search on high-density patches by the Meteorus pulchricornis.

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    Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

    2014-01-01

    Less attention has been paid to the parasitoid-host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids-host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  8. Host density drives the postglacial migration of the tree parasite, Epifagus virginiana.

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    Tsai, Yi-Hsin Erica; Manos, Paul S

    2010-09-28

    To survive changes in climate, successful species shift their geographic ranges to remain in suitable habitats. For parasites and other highly specialized species, distributional changes not only are dictated by climate but can also be engineered by their hosts. The extent of host control on parasite range expansion is revealed through comparisons of host and parasite migration and demographic histories. However, understanding the codistributional history of entire forest communities is complicated by challenges in synthesizing datasets from multiple interacting species of differing datatypes. Here we integrate genetic and fossil pollen datasets from a host-parasite pair; specifically, the population structure of the parasitic plant (Epifagus virginiana) was compared with both its host (Fagus grandifolia) genetic patterns and abundance data from the paleopollen record of the last 21,000 y. Through tests of phylogeographic structure and spatial linear regression models we find, surprisingly, host range changes had little effect on the parasite's range expansion and instead host density is the main driver of parasite spread. Unlike other symbionts that have been used as proxies to track their host's movements, this parasite's migration routes are incongruent with the host and instead reflect the greater importance of host density in this community's assembly. Furthermore, these results confirm predictions of disease ecological models regarding the role of host density in the spread of pathogens. Due to host density constraints, highly specialized species may have low migration capacities and long lag times before colonization of new areas.

  9. Simulation of climate-tick-host-landscape interactions: Effects of shifts in the seasonality of host population fluctuations on tick densities.

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    Wang, Hsiao-Hsuan; Grant, W E; Teel, P D; Hamer, S A

    2015-12-01

    Tick vector systems are comprised of complex climate-tick-host-landscape interactions that are difficult to identify and estimate from empirical observations alone. We developed a spatially-explicit, individual-based model, parameterized to represent ecological conditions typical of the south-central United States, to examine effects of shifts in the seasonal occurrence of fluctuations of host densities on tick densities. Simulated shifts in the seasonal occurrence of periods of high and low host densities affected both the magnitude of unfed tick densities and the seasonality of tick development. When shifting the seasonal densities of all size classes of hosts (small, medium, and large) synchronously, densities of nymphs were affected more by smaller shifts away from the baseline host seasonality than were densities of larval and adult life stages. When shifting the seasonal densities of only a single size-class of hosts while holding other size classes at their baseline levels, densities of larval, nymph, and adult life stages responded differently. Shifting seasonal densities of any single host-class earlier resulted in a greater increase in adult tick density than when seasonal densities of all host classes were shifted earlier simultaneously. The mean densities of tick life stages associated with shifts in host densities resulted from system-level interactions of host availability with tick phenology. For example, shifting the seasonality of all hosts ten weeks earlier resulted in an approximately 30% increase in the relative degree of temporal co-occurrence of actively host-seeking ticks and hosts compared to baseline, whereas shifting the seasonality of all hosts ten weeks later resulted in an approximately 70% decrease compared to baseline. Differences among scenarios in the overall presence of active host-seeking ticks in the system were due primarily to the degree of co-occurrence of periods of high densities of unfed ticks and periods of high densities

  10. Efficiency of vibrational sounding in parasitoid host location depends on substrate density.

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    Fischer, S; Samietz, J; Dorn, S

    2003-10-01

    Parasitoids of concealed hosts have to drill through a substrate with their ovipositor for successful parasitization. Hymenopteran species in this drill-and-sting guild locate immobile pupal hosts by vibrational sounding, i.e., echolocation on solid substrate. Although this host location strategy is assumed to be common among the Orussidae and Ichneumonidae there is no information yet whether it is adapted to characteristics of the host microhabitat. This study examined the effect of substrate density on responsiveness and host location efficiency in two pupal parasitoids, Pimpla turionellae and Xanthopimpla stemmator (Hymenoptera: Ichneumonidae), with different host-niche specialization and corresponding ovipositor morphology. Location and frequency of ovipositor insertions were scored on cylindrical plant stem models of various densities. Substrate density had a significant negative effect on responsiveness, number of ovipositor insertions, and host location precision in both species. The more niche-specific species X. stemmator showed a higher host location precision and insertion activity. We could show that vibrational sounding is obviously adapted to the host microhabitat of the parasitoid species using this host location strategy. We suggest the attenuation of pulses during vibrational sounding as the energetically costly limiting factor for this adaptation.

  11. Amazonian onchocerciasis: parasitological profiles by host-age, sex, and endemicity in southern Venezuela.

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    Vivas-Martínez, S; Basáñez, M G; Botto, C; Rojas, S; García, M; Pacheco, M; Curtis, C F

    2000-11-01

    This paper describes, for the human onchocerciasis focus of southern Venezuela, the age profiles of Onchocerca volvulus microfilarial (mf) and nodule prevalence, mf intensity, and mf aggregation for the whole examined population (836 Yanomami people) living in 20 villages, and for these communities classified according to endemicity levels (hypoendemic: < or = 20 %; mesoendemic: 21-59 %; hyperendemic: < or = 60 % infected). Mf prevalence and intensity increased with age, particularly in the hyperendemic areas, and there were no marked differences between the sexes. The prevalence of nodules followed the same age pattern. Fifty percent mf prevalence was reached in the 15-19 year age-class when the population was taken as a whole; nearly in the 10 to 14-year-olds for the hyperendemic level, in those aged 20-29 years in mesoendemic areas, and not reached at all in hypoendemic villages. The degree of mf aggregation was measured by the k value of the negative binomial distribution and by the variance to mean ratio (VMR). The relationship between the standard deviation (S.D.) of mf counts and the mean mf density was also explored. These 3 indices (k, VMR, and S.D.) showed a tendency to increase with both mean mf load and host age. Since infection intensity and host age were themselves positively related, it was not possible to draw definite conclusions about age-specific changes of parasite aggregation. There was not a significant decrease of mf intensity after an earlier peak neither was there a shift towards younger ages of the maximum no. of mf/mg reached as the endemicity level increased. These results are discussed in relation to detection of density dependence in the human host, selection of an indicator age-group for rapid epidemiological assessment (REA) methods, and strategies of ivermectin distribution in the Amazonian focus. It is recommended that, for the Amazonian onchocerciasis focus, the indicator group for REA consists of all those aged 15 years and over.

  12. The trans-generational impact of population density signals on host-parasite interactions.

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    Michel, Jessica; Ebert, Dieter; Hall, Matthew D

    2016-11-25

    The density of a host population is a key parameter underlying disease transmission, but it also has implications for the expression of disease through its effect on host physiology. In response to higher densities, individuals are predicted to either increase their immune investment in response to the elevated risk of parasitism, or conversely to decrease their immune capacity as a consequence of the stress of a crowded environment. However, an individual's health is shaped by many different factors, including their genetic background, current environmental conditions, and maternal effects. Indeed, population density is often sensed through the presence of info-chemicals in the environment, which may influence a host's interaction with parasites, and also those of its offspring. All of which may alter the expression of disease, and potentially uncouple the presumed link between changes in host density and disease outcomes. In this study, we used the water flea Daphnia magna and its obligate bacterial parasite Pasteuria ramosa, to investigate how signals of high host density impact on host-parasite interactions over two consecutive generations. We found that the chemical signals from crowded treatments induced phenotypic changes in both the parental and offspring generations. In the absence of a pathogen, life-history changes were genotype-specific, but consistent across generations, even when the signal of density was removed. In contrast, the influence of density on infected animals depended on the trait and generation of exposure. When directly exposed to signals of high-density, host genotypes responded differently in how they minimised the severity of disease. Yet, in the subsequent generation, the influence of density was rarely genotype-specific and instead related to ability of the host to minimise the onset of infection. Our findings reveal that population level correlations between host density and infection capture only part of the complex relationship

  13. High nymphal host density and mortality negatively impact parasitoid complex during an insect herbivore outbreak.

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    Hall, Aidan A G; Johnson, Scott N; Cook, James M; Riegler, Markus

    2017-08-26

    Insect herbivore outbreaks frequently occur and this may be due to factors that restrict top-down control by parasitoids, for example, host-parasitoid asynchrony, hyperparasitization, resource limitation and climate. Few studies have examined host-parasitoid density relationships during an insect herbivore outbreak in a natural ecosystem with diverse parasitoids. We studied parasitization patterns of Cardiaspina psyllids during an outbreak in a Eucalyptus woodland. First, we established the trophic roles of the parasitoids through a species-specific multiplex PCR approach on mummies from which parasitoids emerged. Then, we assessed host-parasitoid density relationships across three spatial scales (leaf, tree and site) over one year. We detected four endoparasitoid species of the family Encyrtidae (Hymenoptera); two primary parasitoid and one heteronomous hyperparasitoid Psyllaephagus species (the latter with female development as a primary parasitoid and male development as a hyperparasitoid), and the hyperparasitoid Coccidoctonus psyllae. Parasitoid development was host-synchronized, although synchrony between sites appeared constrained during winter (due to temperature differences). Parasitization was predominantly driven by one primary parasitoid species and was mostly inversely host-density dependent across the spatial scales. Hyperparasitization by C. psyllae was psyllid-density dependent at the site scale, however, this only impacted the rarer primary parasitoid. High larval parasitoid mortality due to density-dependent nymphal psyllid mortality (a consequence of resource limitation) compounded by a summer heat wave was incorporated in the assessment and resulted in density independence of host-parasitoid relationships. As such, high larval parasitoid mortality during insect herbivore outbreaks may contribute to the absence of host density-dependent parasitization during outbreak events. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  14. Effects of intra- and interpatch host density on egg parasitism by three species of Trichogramma.

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    Grieshop, Matthew J; Flinn, Paul W; Nechols, James R

    2010-01-01

    Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley - as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more

  15. A study of the early detection of insect infestations and density/distribution of host plants

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    Hart, W. G.; Ingle, S. J.; Davis, M. R. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Significant results have been obtained in the identification of citrus, sugarcane, winter vegetables, irrigated pastures, and unimproved pastures which contain brush. Land without vegetation, lakes, roads, and waterways can also be determined. Different densities of vegetation covering some cultivated areas are apparent. The practical applications of these results are many. The abundance of host plants of pests can be determined. Avenues of entry of pests can be plotted, facilitating control or preventing entry of pest species. The boundaries of areas to be quarantined can be accurately established after viewing the S-190B data. Better cultural methods can be employed such as planning where to plant certain crops that indirectly are detrimental to those already growing. This would relate to such factors as pesticide drift or alternate hosts of major pests.

  16. Vegetation Management and Host Density Influence Bee-Parasite Interactions in Urban Gardens.

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    Cohen, Hamutahl; Quistberg, Robyn D; Philpott, Stacy M

    2017-12-08

    Apocephalus borealis phorid flies, a parasitoid of bumble bees and yellow jacket wasps in North America, was recently reported as a novel parasitoid of the honey bee Apis mellifera Linnaeus (Hymenoptera: Apidae). Little is known about the ecology of this interaction, including phorid fecundity on bee hosts, whether phorid-bee parasitism is density dependent, and which local habitat and landscape features may correlate with changes in parasitism rates for either bumble or honey bees. We examined the impact of local and landscape drivers and host abundance on phorid parasitism of A. mellifera and the bumble bee Bombus vosnesenskii Radoszkowski (Hymenoptera: Apidae). We worked in 19 urban gardens along the North-Central Coast of California, where phorid parasitism of honey bees was first reported in 2012. We collected and incubated bees for phorid emergence, and surveyed local vegetation, ground cover, and floral characteristics as well as land cover types surrounding gardens. We found that phorid parasitism was higher on bumble bees than on honey bees, and phorids produced nearly twice as many pupae on individual bumble bee hosts than on honey bee hosts. Parasitism of both bumble and honey bees increased with abundance of honey bees in a site. Differences in landscape surroundings did not correlate with parasitism, but local factors related to bee resource provisioning (e.g., tree and shrub abundance) positively correlated with increased parasitism. This research thus helps to document and describe conditions that may have facilitated phorid fly host shift to honey bees and further elucidate how resource provisioning in urban gardens influences bee-parasite interactions. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Emergency rabies control in a community of two high-density hosts

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    Singer Alexander

    2012-06-01

    Full Text Available Abstract Background Rabies is a fatal viral disease that potentially can affect all mammals. Terrestrial rabies is not present in the United Kingdom and has been eliminated from Western Europe. Nevertheless the possibility remains that rabies could be introduced to England, where it would find two potentially suitable hosts, red foxes and badgers. With the aim to analyse the spread and emergency control of rabies in this two species host community, a simulation model was constructed. Different control strategies involving anti-rabies vaccination and population culling were developed, considering control application rates, spatial extent and timing. These strategies were evaluated for efficacy and feasibility to control rabies in hypothetical rural areas in the South of England immediately after a disease outbreak. Results The model confirmed that both fox and badger populations, separately, were competent hosts for the spread of rabies. Realistic vaccination levels were not sufficient to control rabies in high-density badger populations. The combined species community was a very strong rabies host. However, disease spread within species appeared to be more important than cross-species infection. Thus, the drivers of epidemiology depend on the potential of separate host species to sustain the disease. To control a rabies outbreak in the two species, both species had to be targeted. Realistic and robust control strategies involved vaccination of foxes and badgers, but also required badger culling. Although fox and badger populations in the UK are exceptionally dense, an outbreak of rabies can be controlled with a higher than 90% chance, if control response is quick and follows a strict regime. This requires surveillance and forceful and repeated control campaigns. In contrast, an uncontrolled rabies outbreak in the South of England would quickly develop into a strong epizootic involving tens of thousands of rabid foxes and badgers. Conclusions If

  18. Density-dependence and within-host competition in a semelparous parasite of leaf-cutting ants

    DEFF Research Database (Denmark)

    Hughes, William; Petersen, Klaus; Ugelvig, Line

    2004-01-01

    the effects of parasite density and heterogeneity on parasite virulence and fitness using four strains of the entomopathogenic fungus, Metarhizium anisopliae var. anisopliae, and its leaf-cutting ant host Acromyrmex echinatior as the model system.RESULTS:The relationship between parasite density and infection...

  19. Comparative Analysis of Drosophila melanogaster Gut Microbiota with Respect to Host Strain, Sex, and Age.

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    Han, Gangsik; Lee, Hyo Jung; Jeong, Sang Eun; Jeon, Che Ok; Hyun, Seogang

    2017-07-01

    Microbiota has a significant impact on the health of the host individual. The complexity of the interactions between mammalian hosts and their microbiota highlights the value of using Drosophila melanogaster as a model organism, because of its relatively simple microbial community and ease of physiological and genetic manipulation. However, highly variable and sometimes inconsistent results regarding the microbiota of D. melanogaster have been reported for host samples collected from different geographical locations; discrepancies that may be because of the inherent physiological conditions of the D. melanogaster host. Here, we conducted a comparative analysis of the gut microbiota of two D. melanogaster laboratory strains, w 1118 and Canton S, with respect to the sex and age of the host, by pyrosequencing of the 16S rRNA gene. In addition to the widespread and abundant commensal bacterial genera Lactobacillus and Acetobacter, we identified Enterococcus and Leuconostoc as major host-strain-specific bacterial genera. The relative proportions of these bacterial genera, and those of the species within each, were found to differ markedly with respect to strain, sex, and age of the host, even though host individuals were reared under the same nutritional conditions. By using various bioinformatic tools, we uncovered several characteristic features of microbiota corresponding to specific categories of the flies: host-sex-bias association of specific bacteria, age-dependent alteration of microbiota across host species and sex, and uniqueness of the microbiota of female w 1118 flies. Our results, thus, help to further our understanding of host-microbe interactions in the D. melanogaster model.

  20. Demographic models reveal the shape of density dependence for a specialist insect herbivore on variable host plants.

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    Miller, Tom E X

    2007-07-01

    1. It is widely accepted that density-dependent processes play an important role in most natural populations. However, persistent challenges in our understanding of density-dependent population dynamics include evaluating the shape of the relationship between density and demographic rates (linear, concave, convex), and identifying extrinsic factors that can mediate this relationship. 2. I studied the population dynamics of the cactus bug Narnia pallidicornis on host plants (Opuntia imbricata) that varied naturally in relative reproductive effort (RRE, the proportion of meristems allocated to reproduction), an important plant quality trait. I manipulated per-plant cactus bug densities, quantified subsequent dynamics, and fit stage-structured models to the experimental data to ask if and how density influences demographic parameters. 3. In the field experiment, I found that populations with variable starting densities quickly converged upon similar growth trajectories. In the model-fitting analyses, the data strongly supported a model that defined the juvenile cactus bug retention parameter (joint probability of surviving and not dispersing) as a nonlinear decreasing function of density. The estimated shape of this relationship shifted from concave to convex with increasing host-plant RRE. 4. The results demonstrate that host-plant traits are critical sources of variation in the strength and shape of density dependence in insects, and highlight the utility of integrated experimental-theoretical approaches for identifying processes underlying patterns of change in natural populations.

  1. Plant Killing by Mutualistic Ants Increases the Density of Host Species Seedlings in the Dry Forest of Costa Rica

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    Amador-Vargas, Sabrina

    2012-01-01

    Some species of plant-mutualistic ants kill the vegetation growing in the vicinities of their host plant, creating an area of bare ground (clearing). The reduced competition in the clearing may facilitate the establishment of host species sprouts (clones and seedlings), which in turn benefits the ants with additional food and shelter (“sprout-establishment hypothesis”). To test this hypothesis, the density and origin of Acacia collinsii sprouts growing inside clearings and in the vicinities o...

  2. Density-dependence and within-host competition in a semelparous parasite of leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Thomsen Lene

    2004-11-01

    Full Text Available Abstract Background Parasite heterogeneity and within-host competition are thought to be important factors influencing the dynamics of host-parasite relationships. Yet, while there have been many theoretical investigations of how these factors may act, empirical data is more limited. We investigated the effects of parasite density and heterogeneity on parasite virulence and fitness using four strains of the entomopathogenic fungus, Metarhizium anisopliae var. anisopliae, and its leaf-cutting ant host Acromyrmex echinatior as the model system. Results The relationship between parasite density and infection was sigmoidal, with there being an invasion threshold for an infection to occur (an Allee effect. Although spore production was positively density-dependent, parasite fitness decreased with increasing parasite density, indicating within-host scramble competition. The dynamics differed little between the four strains tested. In mixed infections of three strains the infection-growth dynamics were unaffected by parasite heterogeneity. Conclusions The strength of within-host competition makes dispersal the best strategy for the parasite. Parasite heterogeneity may not have effected virulence or the infection dynamics either because the most virulent strain outcompeted the others, or because the interaction involved scramble competition that was impervious to parasite heterogeneity. The dynamics observed may be common for virulent parasites, such as Metarhizium, that produce aggregated transmission stages. Such parasites make useful models for investigating infection dynamics and the impact of parasite competition.

  3. Explaining variance of avian malaria infection in the wild: the importance of host density, habitat, individual life-history and oxidative stress.

    Science.gov (United States)

    Isaksson, Caroline; Sepil, Irem; Baramidze, Vladimer; Sheldon, Ben C

    2013-04-08

    Avian malaria (Plasmodium sp.) is globally widespread, but considerable variation exists in infection (presence/absence) patterns at small spatial scales. This variation can be driven by variation in ecology, demography, and phenotypic characters, in particular those that influence the host's resistance. Generation of reactive oxygen species (ROS) is one of the host's initial immune responses to combat parasitic invasion. However, long-term ROS exposure can harm the host and the redox response therefore needs to be adjusted according to infection stage and host phenotype. Here we use experimental and correlational approaches to assess the relative importance of host density, habitat composition, individual level variation and redox physiology for Plasmodium infection in a wild population of great tits, Parus major. We found that 36% of the great tit population was infected with Plasmodium (22% P. relictum and 15% P. circumflexum prevalence) and that patterns of infection were Plasmodium species-specific. First, the infection of P. circumflexum was significantly higher in areas with experimental increased host density, whereas variation in P. relictum infection was mainly attributed to age, sex and reproduction. Second, great tit antioxidant responses - total and oxidizied glutathione - showed age- , sex- and Plasmodium species-specific patterns between infected and uninfected individuals, but reactive oxygen metabolites (ROM) showed only a weak explanatory power for patterns of P. relictum infection. Instead ROM significantly increased with Plasmodium parasitaemia. These results identify some key factors that influence Plasmodium infection in wild birds, and provide a potential explanation for the underlying physiological basis of recently documented negative effects of chronic avian malaria on survival and reproductive success.

  4. Effects of juvenile host density and food availability on adult immune response, parasite resistance and virulence in a Daphnia-parasite system.

    Directory of Open Access Journals (Sweden)

    Corine N Schoebel

    Full Text Available Host density can increase infection rates and reduce host fitness as increasing population density enhances the risk of becoming infected either through increased encounter rate or because host condition may decline. Conceivably, potential hosts could take high host density as a cue to up-regulate their defence systems. However, as host density usually covaries with food availability, it is difficult to examine the importance of host density in isolation. Thus, we performed two full-factorial experiments that varied juvenile densities of Daphnia magna (a freshwater crustacean and food availability independently. We also included a simulated high-density treatment, where juvenile experimental animals were kept in filtered media that previously maintained Daphnia at high-density. Upon reaching adulthood, we exposed the Daphnia to their sterilizing bacterial parasite, Pasteuria ramosa, and examined how the juvenile treatments influenced the likelihood and severity of infection (Experiment I and host immune investment (Experiment II. Neither juvenile density nor food treatments affected the likelihood of infection; however, well-fed hosts that were well-fed as juveniles produced more offspring prior to sterilization than their less well-fed counterparts. By contrast, parasite growth was independent of host juvenile resources or host density. Parasite-exposed hosts had a greater number of circulating haemocytes than controls (i.e., there was a cellular immune response, but the magnitude of immune response was not mediated by food availability or host density. These results suggest that density dependent effects on disease arise primarily through correlated changes in food availability: low food could limit parasitism and potentially curtail epidemics by reducing both the host's and parasite's reproduction as both depend on the same food.

  5. Immunity of an alternative host can be overcome by higher densities of its parasitoids Palmistichus elaeisis and Trichospilus diatraeae.

    Directory of Open Access Journals (Sweden)

    Gilberto Santos Andrade

    Full Text Available Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae with its alternative host Anticarsia gemmatalis (Hübner (Lepidoptera: Noctuidae affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes in the cellular defense and encapsulation ability of A. gemmatalis pupae against P. elaeisis or T. diatraeae in adult parasitoid densities of 1, 3, 5, 7, 9, 11 or 13 parasitoids/pupae. We evaluated the total quantity of circulating hemocytes and the encapsulation rate versus density. Increasing parasitoid density reduced the total number of hemocytes in the hemolymph and the encapsulation rate by parasitized pupae. Furthermore, densities of P. elaeisis above 5 parasitoids/pupae caused higher reduction in total hemocyte numbers. The encapsulation rate fell with increasing parasitoid density. However, parasitic invasion by both species induced generally similar responses. The reduction in defensive capacity of A. gemmatalis is related to the adjustment of the density of these parasitoids to their development in this host. Thus, the role of the density of P. elaeisis or T. diatraeae by pupa is induced suppression of cellular defense and encapsulation of the host, even without them possesses a co-evolutionary history. Furthermore, these findings can predict the success of P. elaeisis and T. diatraeae in the control of insect pests through the use of immunology as a tool for evaluation of natural enemies.

  6. Predictors of Dietary Energy Density among Preschool Aged Children

    Directory of Open Access Journals (Sweden)

    Nilmani N.T. Fernando

    2018-02-01

    Full Text Available Childhood obesity is a global problem with many contributing factors including dietary energy density (DED. This paper aims to investigate potential predictors of DED among preschool aged children in Victoria, Australia. Secondary analysis of longitudinal data for 209 mother–child pairs from the Melbourne Infant Feeding, Activity and Nutrition Trial was conducted. Data for predictors (maternal child feeding and nutrition knowledge, maternal dietary intake, home food availability, socioeconomic status were obtained through questionnaires completed by first-time mothers when children were aged 4 or 18 months. Three 24-h dietary recalls were completed when children were aged ~3.5 years. DED was calculated utilizing three methods: “food only”, “food and dairy beverages”, and “food and all beverages”. Linear regression analyses were conducted to identify associations between predictors and these three measures of children’s DED. Home availability of fruits (β: −0.82; 95% CI: −1.35, −0.29, p = 0.002 for DEDfood; β: −0.42; 95% CI: −0.82, −0.02, p = 0.041 for DEDfood+dairy beverages and non-core snacks (β: 0.11; 95% CI: 0.02, 0.20, p = 0.016 for DEDfood; β: 0.09; 95% CI: 0.02, 0.15, p = 0.010 for DEDfood+dairy beverages were significantly associated with two of the three DED measures. Providing fruit at home early in a child’s life may encourage the establishment of healthful eating behaviors that could promote a diet that is lower in energy density later in life. Home availability of non-core snacks is likely to increase the energy density of preschool children’s diets, supporting the proposition that non-core snack availability at home should be limited.

  7. Effects of host species and population density on Anoplophora glabripennis flight propensity

    Science.gov (United States)

    Joseph A. Francese; David R. Lance; Baode Wang; Zhichun Xu; Alan J. Sawyer; Victor C. Mastro

    2007-01-01

    Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae), the Asian longhorned beetle (ALB) is a pest of hardwoods in its native range of China. While the host range of this pest has been studied extensively, its mechanisms for host selection are still unknown. Our goal was to study the factors influencing movement and orientation of adult ALB...

  8. Density threshold for Mopeia virus invasion and persistence in its host Mastomys natalensis

    DEFF Research Database (Denmark)

    Goyens, J.; Reijniers, J.; Borremans, B.

    2013-01-01

    . We developed a spatially explicit and individual-based SEIR model of Mopeia virus in multimammate mice Mastomys natalensis. This is an interesting model system for studying abundance thresholds because the host is the most common African rodent, populations fluctuate considerably and the virus...... is closely related to Lassa virus but non-pathogenic to humans so can be studied safely in the field. The simulations show that, while host density clearly is important, sharp thresholds are only to be expected for persistence (and not for invasion), since at short time-spans (as during invasion...

  9. Active zones of mammalian neuromuscular junctions: formation, density, and aging.

    Science.gov (United States)

    Nishimune, Hiroshi

    2012-12-01

    Presynaptic active zones are synaptic vesicle release sites that play essential roles in the function and pathology of mammalian neuromuscular junctions (NMJs). The molecular mechanisms of active zone organization use presynaptic voltage-dependent calcium channels (VDCCs) in NMJs as scaffolding proteins. VDCCs interact extracellularly with the muscle-derived synapse organizer, laminin β2 and interact intracellularly with active zone-specific proteins, such as Bassoon, CAST/Erc2/ELKS2alpha, ELKS, Piccolo, and RIMs. These molecular mechanisms are supported by studies in P/Q- and N-type VDCCs double-knockout mice, and they are consistent with the pathological conditions of Lambert-Eaton myasthenic syndrome and Pierson syndrome, which are caused by autoantibodies against VDCCs or by a laminin β2 mutation. During normal postnatal maturation, NMJs maintain the density of active zones, while NMJs triple their size. However, active zones become impaired during aging. Propitiously, muscle exercise ameliorates the active zone impairment in aged NMJs, which suggests the potential for therapeutic strategies. © 2012 New York Academy of Sciences.

  10. Effects of formulation and host nematode density on the ability of in vitro-produced pasteuria endospores to control its host Belonolaimus longicaudatus.

    Science.gov (United States)

    Luc, John E; Pang, Wenjing; Crow, William T; Giblin-Davis, Robin M

    2010-06-01

    The effect of nematode population density at the time of application and formulations of in vitro-produced Pasteuria spp. endospores on the final population density of Belonolaimus longicaudatus was studied in an 84-d-long pot bioassay. The experiment utilized a factorial design consisting of 30 or 300 B. longicaudatus /100 cm(3) of sandy soil and three formulations of in vitro-produced Pasteuria spp. endospores (nontreated, granular, or liquid). No differences were observed in percent endospore attachment between nematode inoculum levels during either trial. Granular and liquid formulations of in vitro-produced endospores suppressed nematode population densities by 22% and 59% in the first trial and 20% and 63% in the second, respectively compared with the nontreated control. The liquid formulation increased percent endospore attachment by 147% and 158%, respectively, compared with the granular formulation. The greatest root retention by the host plant was observed at the lower B. longicaudatus inoculation level following application of the liquid formulation. While both the granular and liquid formulations reduced B. longicaudatus population densities in the soil, the liquid spore suspension was most effective.

  11. Space/age forestry: Implications of planting density and rotation age in SRIC management decisions

    Energy Technology Data Exchange (ETDEWEB)

    Merriam, R.A.; Phillips, V.D.; Liu, W.

    1993-12-31

    Short-rotation intensive-culture (SRIC) of promising tree crops is being evaluated worldwide for the production of methanol, ethanol, and electricity from renewable biomass resources. Planting density and rotation age are fundamental management decisions associated with SRIC energy plantations. Most studies of these variables have been conducted without the benefit of a unifying theory of the effects of growing space and rotation age on individual tree growth and stand level productivity. A modeling procedure based on field trials of Eucalyptus spp. is presented that evaluates the growth potential of a tree in the absence and presence of competition of neighboring trees in a stand. The results of this analysis are useful in clarifying economic implications of different growing space and rotation age decisions that tree plantation managers must make. The procedure is readily applicable to other species under consideration for SRIC plantations at any location.

  12. Plant host range of Verticillium longisporum and microsclerotia density in Swedisch soils

    NARCIS (Netherlands)

    Johansson, A.; Goud, J.C.; Dixelius, C.

    2006-01-01

    Verticillium longisporum is a soil-borne fungal pathogen causing vascular wilt of Brassica crops. This study was conducted to enhance our knowledge on the host range of V. longisporum. Seven crop species (barley, oat, oilseed rape, pea, red clover, sugar beet and wheat) and five weed species (barren

  13. Habitat selection of a parasitoid mediated by volatiles informing on host and intraguild predator densities

    DEFF Research Database (Denmark)

    Cotes, Belén; Rännbäck, Linda Marie; Björkman, Maria

    2015-01-01

    both a parasitoid and its host, parasitoids may reduce the risk of intraguild predation (IGP) by avoiding such patches. In this study, we examined whether the presence of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana in soil habitats of a root herbivore, Delia radicum, affects...

  14. Age, sedimentary environments, and other aspects of sandstone and related host rocks for uranium deposits

    International Nuclear Information System (INIS)

    1983-01-01

    Project II of the Uranium Geology Working Group was assigned to the study of sedimentary basins and sandstone - type uranium deposits. About 40% of the worlds's uranium resources are contained in sandstone-type deposits, which has led to extensive research. The research was carried out mainly by correspondence, and the results reported by 21 geologists from 10 nations are summarized in this report. It investigated five topics dealing with important aspects of the geology of uranium ores in sandstone host formations: age of host rock; partitioning of uranium between continental and marine sediments; latitude limitation on formation of sandstone deposits; effect of rock formation dip on sandstone ores; usefulness of stable isotope and fluid inclusion studies. The results of studies on these subjects form part of a wider programme of the Working Group, whose final results will be presented at the 27th International Geological Congress in Moscow in 1984

  15. Effect of host age on the transplantation, growth, and radiation response of EMT6 tumors

    International Nuclear Information System (INIS)

    Rockwell, S.

    1981-01-01

    The characteristics of EMT6 tumors in young adult and aged BALB/c KaRw mice were compared. The number of tumor cells implanted s.c. necessary to cause tumors in 50% of the injection sites was lower in aging than in young adult mice. The latent period of intradermally implanted tumors was shorter in aging mice than in young animals; however, the growth curves of established tumors were similar. The number and appearance of lung colonies after injection of cells i.v. and the pattern of spontaneous metastases were similar in young and aged animals. Radiation dose-response curves for the cells of tumors in young and aging mice were different and suggested that the proportion of hypoxic cells was higher in tumors on aging animals. These findings suggest that both immunological and nonimmunological tumor-host interactions differ in young and aged animals and that such factors may influence the natural history of the tumor and the response of the tumor to treatment

  16. Effects of host plant and larval density on intraspecific competition in larvae of the emerald ash borer (Coleoptera: Buprestidae).

    Science.gov (United States)

    Duan, Jian J; Larson, Kristi; Watt, Tim; Gould, Juli; Lelito, Jonathan P

    2013-12-01

    Competition for food, mates, and space among different individuals of the same insect species can affect density-dependent regulation of insect abundance or population dynamics. The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a serious invasive pest of North American ash (Fraxinus spp.) trees, with its larvae feeding in serpentine galleries between the interface of sapwood and phloem tissues of ash trees. Using artificial infestation of freshly cut logs of green ash (Fraxinus pennsylvanica Marshall) and tropical ash (Fraxinus uhdei [Wenzig] Lingelsh) with a series of egg densities, we evaluated the mechanism and outcome of intraspecific competition in larvae of A. planipennis in relation to larval density and host plant species. Results from our study showed that as the egg densities on each log (1.5-6.5 cm in diameter and 22-25 cm in length) increased from 200 to 1,600 eggs per square meter of surface area, larval survivorship declined from ≍68 to 10% for the green ash logs, and 86 to 55% for tropical ash logs. Accordingly, larval mortality resulting from cannibalism, starvation, or both, significantly increased as egg density increased, and the biomass of surviving larvae significantly decreased on both ash species. When larval density was adjusted to the same level, however, larval mortality from intraspecific competition was significantly higher and mean biomasses of surviving larvae was significantly lower in green ash than in tropical ash. The role of intraspecific competition of A. planipennis larvae in density-dependent regulation of its natural population dynamics is discussed.

  17. The use of Skylab data to study the early detection of insect infestations and density and distribution of host plants

    Science.gov (United States)

    Hart, W. G.; Ingle, S. J.; Davis, M. R.

    1975-01-01

    The detection of insect infestations and the density and distribution of host plants were studied using Skylab data, aerial photography and ground truth simultaneously. Additional ground truth and aerial photography were acquired between Skylab passes. Three test areas were selected: area 1, of high density citrus, was located northwest of Mission, Texas; area 2, 20 miles north of Weslaco, Texas, irrigated pastures and brush-covered land; area 3 covered the entire Lower Rio Grande Valley and adjacent areas of Mexico. A color composite picture of S-190A data showed patterns of vegetation on both sides of the Rio Grande River clearly delineating the possible avenues of entry of pest insects from Mexico into the United States or from the United States into Mexico. Vegetation that could be identified with conventional color and color IR film included: citrus, brush, sugarcane, alfalfa, irrigated and unimproved pastures.

  18. Charge transport in disordered organic host-guest systems: effects of carrier density and electric field

    NARCIS (Netherlands)

    Yimer, Y.Y.; Bobbert, P.A.; Coehoorn, R.

    2008-01-01

    We investigate charge transport in disordered organic host–guest systems with a bimodal Gaussian density of states (DOS). The energy difference between the two Gaussians defines the trap depth. By solving the Pauli master equation for the hopping of charge carriers on a regular lattice with site

  19. Charge transport in disordered organic host-guest systems: effects of carrier density and electric field

    NARCIS (Netherlands)

    Yimer, Y.Y.; Bobbert, P.A.; Coehoorn, R.

    2009-01-01

    We investigate charge transport in disordered organic host–guest systems with a bimodal Gaussian density of states. The energy difference between the peaks of the two Gaussians defines the trap depth. By solving the Pauli master equation for the hopping of charge carriers on a regular lattice we

  20. Hydrology and density feedbacks control the ecology of intermediate hosts of schistosomiasis across habitats in seasonal climates.

    Science.gov (United States)

    Perez-Saez, Javier; Mande, Theophile; Ceperley, Natalie; Bertuzzo, Enrico; Mari, Lorenzo; Gatto, Marino; Rinaldo, Andrea

    2016-06-07

    We report about field and theoretical studies on the ecology of the aquatic snails (Bulinus spp. and Biomphalaria pfeifferi) that serve as obligate intermediate hosts in the complex life cycle of the parasites causing human schistosomiasis. Snail abundance fosters disease transmission, and thus the dynamics of snail populations are critically important for schistosomiasis modeling and control. Here, we single out hydrological drivers and density dependence (or lack of it) of ecological growth rates of local snail populations by contrasting novel ecological and environmental data with various models of host demography. Specifically, we study various natural and man-made habitats across Burkina Faso's highly seasonal climatic zones. Demographic models are ranked through formal model comparison and structural risk minimization. The latter allows us to evaluate the suitability of population models while clarifying the relevant covariates that explain empirical observations of snail abundance under the actual climatic forcings experienced by the various field sites. Our results link quantitatively hydrological drivers to distinct population dynamics through specific density feedbacks, and show that statistical methods based on model averaging provide reliable snail abundance projections. The consistency of our ranking results suggests the use of ad hoc models of snail demography depending on habitat type (e.g., natural vs. man-made) and hydrological characteristics (e.g., ephemeral vs. permanent). Implications for risk mapping and space-time allocation of control measures in schistosomiasis-endemic contexts are discussed.

  1. Agrochemicals increase risk of human schistosomiasis by supporting higher densities of intermediate hosts.

    Science.gov (United States)

    Halstead, Neal T; Hoover, Christopher M; Arakala, Arathi; Civitello, David J; De Leo, Giulio A; Gambhir, Manoj; Johnson, Steve A; Jouanard, Nicolas; Loerns, Kristin A; McMahon, Taegan A; Ndione, Raphael A; Nguyen, Karena; Raffel, Thomas R; Remais, Justin V; Riveau, Gilles; Sokolow, Susanne H; Rohr, Jason R

    2018-02-26

    Schistosomiasis is a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries. Increased prevalence and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife and a projected 2- to 5-fold increase in global agrochemical use by 2050. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, a herbicide, and an insecticide, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat and decreasing densities of snail predators. Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomes. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing.

  2. First principles density functional calculation of magnetic moment and hyperfine fields of dilute transition metal impurities in Gd host

    International Nuclear Information System (INIS)

    Mohanta, S.K.; Mishra, S.N.; Srivastava, S.K.

    2014-01-01

    We present first principles calculations of electronic structure and magnetic properties of dilute transition metal (3d, 4d and 5d) impurities in a Gd host. The calculations have been performed within the density functional theory using the full potential linearized augmented plane wave technique and the GGA+U method. The spin and orbital contributions to the magnetic moment and the hyperfine fields have been computed. We find large magnetic moments for 3d (Ti–Co), 4d (Nb–Ru) and 5d (Ta–Os) impurities with magnitudes significantly different from the values estimated from earlier mean field calculation [J. Magn. Magn. Mater. 320 (2008) e446–e449]. The exchange interaction between the impurity and host Gd moments is found to be positive for early 3d elements (Sc–V) while in all other cases an anti-ferromagnetic coupling is observed. The trends for the magnetic moment and hyperfine field of d-impurities in Gd show qualitative difference with respect to their behavior in Fe, Co and Ni. The calculated total hyperfine field, in most cases, shows excellent agreement with the experimental results. A detailed analysis of the Fermi contact hyperfine field has been made, revealing striking differences for impurities having less or more than half filled d-shell. The impurity induced perturbations in host moments and the change in the global magnetization of the unit cell have also been computed. The variation within each of the d-series is found to correlate with the d–d hybridization strength between the impurity and host atoms. - Highlights: • Detailed study of transition metal impurities in ferromagnetic Gd has been carried out. • The trends in impurity magnetic moment are qualitatively different from Fe, Co and Ni. • The variation within each of the d-series is found to correlate with the d–d hybridization strength between the impurity and host atoms. • Experimental trend in a hyperfine field has been reproduced successfully

  3. Postnatal Age Is a Critical Determinant of the Neonatal Host Response to Sepsis

    Science.gov (United States)

    Wynn, James L; Guthrie, Scott O; Wong, Hector R; Lahni, Patrick; Ungaro, Ricardo; Lopez, M Cecilia; Baker, Henry V; Moldawer, Lyle L

    2015-01-01

    Neonates manifest a unique host response to sepsis even among other children. Preterm neonates may experience sepsis soon after birth or during often-protracted birth hospitalizations as they attain physiologic maturity. We examined the transcriptome using genome-wide expression profiling on prospectively collected peripheral blood samples from infants evaluated for sepsis within 24 h after clinical presentation. Simultaneous plasma samples were examined for alterations in inflammatory mediators. Group designation (sepsis or uninfected) was determined retrospectively on the basis of clinical exam and laboratory results over the next 72 h from the time of evaluation. Unsupervised analysis showed the major node of separation between groups was timing of sepsis episode relative to birth (early, <3 d, or late, ≥3 d). Principal component analyses revealed significant differences between patients with early or late sepsis despite the presence of similar key immunologic pathway aberrations in both groups. Unique to neonates, the uninfected state and host response to sepsis is significantly affected by timing relative to birth. Future therapeutic approaches may need to be tailored to the timing of the infectious event based on postnatal age. PMID:26052715

  4. Effect of age, photoperiod and host availability on the parasitism behavior of Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae)

    International Nuclear Information System (INIS)

    Silva-Torres, Christian S.A.; Barros, Reginaldo; Torres, Jorge B.

    2009-01-01

    The high reproduction rate, potential to cause damage, wide geographic distribution and resistance to insecticides of Plutella xylostella (L.) makes difficult its efficient control. However, larvae and pupae of this pest are naturally parasitized by Oomyzus Sokolowskii (Kurdjumov), providing opportunities to improve the natural parasitism. This study investigated the effects of the age of adult parasitoids, host availability and time of exposure on O. sokolowskii parasitism behavior. The number of larvae encounters by parasitoid females and the parasitism rate increased with parasitoid age up to 96 h. The parasitization was higher when wasps received a constant number of hosts daily in comparison with a random number (13.3 versus 8.9 larvae parasitized). Female parasitization activity was maintained up to the age of 20 days in both treatments and exhibited similar longevity (constant host = 33.5 d; and random host = 34.7 d). The progeny produced per female and the number of parasitoids emerged per host significantly decreased as wasps aged. There was no significant effect of the light regime (12 h darkness or 12 h light exposure) on the parasitization, although parasitoid was more active after 3 h of light exposure. Therefore, further studies on field application of O. sokolowskii should consider the release of 48 h - to 72 h - old parasitoids at dawn as a way to increase the success of host parasitization. (author)

  5. The role of the ratio of vector and host densities in the evolution of transmission modes in vector-borne diseases. The example of sylvatic Trypanosoma cruzi.

    Science.gov (United States)

    Pelosse, Perrine; Kribs-Zaleta, Christopher M

    2012-11-07

    Pathogens may use different routes of transmission to maximize their spread among host populations. Theoretical and empirical work conducted on directly transmitted diseases suggest that horizontal (i.e., through host contacts) and vertical (i.e., from mother to offspring) transmission modes trade off, on the ground that highly virulent pathogens, which produce larger parasite loads, are more efficiently transmitted horizontally, and that less virulent pathogens, which impair host fitness less significantly, are better transmitted vertically. Other factors than virulence such as host density could also select for different transmission modes, but they have barely been studied. In vector-borne diseases, pathogen transmission rate is strongly affected by host-vector relative densities and by processes of saturation in contacts between hosts and vectors. The parasite Trypanosoma cruzi which is transmitted by triatomine bugs to several vertebrate hosts is responsible for Chagas' disease in Latin America. It is also widespread in sylvatic cycles in the southeastern U.S. in which it typically induces no mortality costs to its customary hosts. Besides classical transmission via vector bites, alternative ways to generate infections in hosts such as vertical and oral transmission (via the consumption of vectors by hosts) have been reported in these cycles. The two major T. cruzi strains occurring in the U.S. seem to exhibit differential efficiencies at vertical and classical horizontal transmissions. We investigated whether the vector-host ratio affects the outcome of the competition between the two parasite strains using an epidemiological two-strain model considering all possible transmission routes for sylvatic T. cruzi. We were able to show that the vector-host ratio influences the evolution of transmission modes providing that oral transmission is included in the model as a possible transmission mode, that oral and classical transmissions saturate at different vector-host

  6. Schistosoma mansoni: assessment of effects of oleic acid, cercarial age and water temperature on parasite-host attraction.

    Science.gov (United States)

    Lee, Vivien S T; Burgess, Jefferey L; Sterling, Charles R; Lutz, Eric A

    2013-09-01

    Although the lifecycle of Schistosoma spp. and pathophysiology of schistosomiasis have been established, the mechanism by which cercariae find their host is not well understood. Speculatively, host infection by random and accidental host contact is not as biologically plausible as a biochemical mechanism of mammalian attraction. A few studies have indicated that biochemical cues and temperature gradients may play a role in host identification, attraction and attachment triggers. This study aimed to elucidate these mechanisms more specifically through evaluation of biochemical, age and temperature influences leading to Schistosoma mansoni cercariae attraction and attachment behaviors. Oleic acid, a common unsaturated free fatty acid in the outer layer of human skin, was tested for cercariae attraction across biologically relevant concentrations. Influence of media type (beeswax, nail varnish and agar), age-dependent behavior variability and environmentally appropriate temperatures (22 and 30 °C) were also evaluated. Results indicated that oleic acid at concentrations of 0.3, 0.9 and 1.8 g/mL in beeswax significantly increased median attachment to media (median attachment of 7.50%, 4.20% and 3.71%, respectively, P0.05). Biochemical, age and environmental factors influencing cercarial host attraction and attachment behavior have been elucidated by this study. This information will inform further development of devices for environmental surveillance and potentially improve cercarial exposure prevention strategies. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  7. Host Age Affects the Development of Southern Catfish Gut Bacterial Community Divergent From That in the Food and Rearing Water.

    Science.gov (United States)

    Zhang, Zhimin; Li, Dapeng; Refaey, Mohamed M; Xu, Weitong; Tang, Rong; Li, Li

    2018-01-01

    Host development influences gut microbial assemblies that may be confounded partly by dietary shifts and the changing environmental microbiota during ontogenesis. However, little is known about microbial colonization by excluding dietary effects and compositional differences in microbiota between the gut and environment at different ontogenetic stages. Herein, a developmental gut microbial experiment under controlled laboratory conditions was conducted with carnivorous southern catfish Silurus meridionalis fed on an identical prey with commensal and abundant microbiota. In this study, we provided a long-term analysis of gut microbiota associated with host age at 8, 18, 35, 65, and 125 day post-fertilization (dpf) and explored microbial relationships among host, food and water environment at 8, 35, and 125 dpf. The results showed that gut microbial diversity in southern catfish tended to increase linearly as host aged. Gut microbiota underwent significant temporal shifts despite similar microbial communities in food and rearing water during the host development and dramatically differed from the environmental microbiota. At the compositional abundance, Tenericute s and Fusobacteria were enriched in the gut and markedly varied with host age, whereas Spirochaetes and Bacteroidetes detected were persistently the most abundant phyla in food and water, respectively. In addition to alterations in individual microbial taxa, the individual differences in gut microbiota were at a lower level at the early stages than at the late stages and in which gut microbiota reached a stable status, suggesting the course of microbial successions. These results indicate that host development fundamentally shapes a key transition in microbial community structure, which is independent of dietary effects. In addition, the dominant taxa residing in the gut do not share their niche habitats with the abundant microbiota in the surrounding environment. It's inferred that complex gut microbiota

  8. Aging and sarcopenia associate with specific interactions between gut microbes, serum biomarkers and host physiology in rats.

    Science.gov (United States)

    Siddharth, Jay; Chakrabarti, Anirikh; Pannérec, Alice; Karaz, Sonia; Morin-Rivron, Delphine; Masoodi, Mojgan; Feige, Jerome N; Parkinson, Scott James

    2017-07-17

    The microbiome has been demonstrated to play an integral role in the maintenance of many aspects of health that are also associated with aging. In order to identify areas of potential exploration and intervention, we simultaneously characterized age-related alterations in gut microbiome, muscle physiology and serum proteomic and lipidomic profiles in aged rats to define an integrated signature of the aging phenotype. We demonstrate that aging skews the composition of the gut microbiome, in particular by altering the Sutterella to Barneseilla ratio, and alters the metabolic potential of intestinal bacteria. Age-related changes of the gut microbiome were associated with the physiological decline of musculoskeletal function, and with molecular markers of nutrient processing/availability, and inflammatory/immune status in aged versus adult rats. Altogether, our study highlights that aging leads to a complex interplay between the microbiome and host physiology, and provides candidate microbial species to target physical and metabolic decline during aging by modulating gut microbial ecology.

  9. Infection of Anopheles gambiae mosquitoes with entomopathogenic fungi: effect of host age and blood-feeding status

    NARCIS (Netherlands)

    Mnyone, L.L.; Kirby, M.J.; Mpingwa, M.W.; Lwetoijera, D.W.; Knols, B.G.J.; Takken, W.; Koenraadt, C.J.M.; Russell, T.L.

    2011-01-01

    Physiological characteristics of insects can influence their susceptibility to fungal infection of which age and nutritional status are among the most important. An understanding of host–pathogen interaction with respect to these physiological characteristics of the host is essential if we are to

  10. Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

    Science.gov (United States)

    Elsner, Ann E.; Burns, Stephen A.; Weiter, John J.

    2002-01-01

    We measured changes to cone photoreceptors in patients with early age-related macular degeneration. The data of 53 patients were compared with normative data for color matching measurements of long- and middle-wavelength-sensitive cones in the central macula. A four-parameter model quantified cone photopigment optical density and kinetics. Cone photopigment optical density was on average less for the patients than for normal subjects and was uncorrelated with visual acuity. More light was needed to reduce the photopigment density by 50% in the steady state for patients. These results imply that cone photopigment optical density is reduced by factors other than slowed kinetics.

  11. Metazoan parasite fauna of the bigeye flounder, Hippoglossina macrops, from Northern Chile. Influence of host age and sex

    Directory of Open Access Journals (Sweden)

    González M Teresa

    2001-01-01

    Full Text Available The metazoan parasite fauna of Hippoglossina macrops (n = 123 from northern Chile (30°S is quantitatively described for the first time, and the role of host age and sex was evaluated. Twelve parasite species were recovered, including 5 ectoparasites (2 Monogenea, 2 Copepoda and 1 Piscicolidae and 7 endoparasites (1 Digenea, 3 Cestoda, 2 Acanthocephala, and 1 Nematoda. The copepod Holobomolochus chilensis, the monogenean Neoheterobothrium sp., the adult acanthocephalan Floridosentis sp. and the hirudinean, Gliptonobdella sp. are new geographical and host records. The most prevalent ectoparasitic species were the monogenean, Neoheterobothrium sp. and the copepod, H. chilensis. Among endoparasites, the acanthocephalans Floridosentis sp. and Corynosoma australe were most prevalent and abundant. Prevalence and mean intensity of infection for most parasitic species were not affected by host sex, however the prevalence of Floridosentis sp. was significantly greater in males. Intensity of infection was positively correlated with host age for Neoheterobothrium sp., and negatively correlated for Floridosentis sp. and H. chilensis. The helminth species richness of the host H. macrops was lower compared to related flatfishes from the Northern Hemisphere. The relationship of the helminth fauna of H. macrops, its feeding habits and ecological habitats are discussed.

  12. Effects of two-age management and clearcutting on songbird density and reproductive success

    Science.gov (United States)

    Jeffery V. Nichols; Petra Bohall Wood

    1995-01-01

    We examined density and reproductive success of passerine species on 7 uncut forest stands and on 12 stands harvested 10-14 years ago on the Monongahela National Forest of West Virginia (6 clearcut stands and 6 stands harvested using 2-age management). In 2-age management, stands resemble a shelterwood cut with 10-30 overstory trees/acre left uncut. Uncut periphery...

  13. Age as a predictive factor of mammographic breast density in Jamaican women

    International Nuclear Information System (INIS)

    Soares, Deanne; Reid, Marvin; James, Michael

    2002-01-01

    AIM: We sought to determine the relationship between age, and other clinical characteristics such as parity, oestrogen use, dietary factors and menstrual history on breast density in Jamaican women. METHODS AND MATERIALS: A retrospective study was done of 891 patients who attended the breast imaging unit. The clinical characteristics were extracted from the patient records. Mammograms were assessed independently by two radiologists who were blinded to the patient clinical characteristics. Breast densities were assigned using the American College of Radiology (ACR) classification. RESULTS: The concordance between the ACR classification of breast density between the two independent radiologists was 92% with k = 0.76 (SE = 0.02, P -2 vs 26.0 ± 5.2 kg m -2 , P < 0.0001). Mammographic breast density decreased with age. The age adjusted odds ratios (ORs) for predictors significantly related to high breast density were parity, OR = 0.79 (95%CI:0.71, 0.88), weight, OR = 0.92 (95% CI:0.91, 0.95), BMI, OR = 0.83 (95% CI:0.78, 0.89), menopause, OR = 0.51 (95% CI:0.36, 0.74) and a history of previous breast surgery, OR 1.6 (95% CI:1.1, 2.3). CONCLUSION: The rate decline of breast density with age in our population was influenced by parity and body composition. Soares, D. et al. (2002)

  14. Influence of Host Genetics and Environment on Nasal Carriage of Staphylococcus aureus in Danish Middle-Aged and Elderly Twins

    DEFF Research Database (Denmark)

    Andersen, Paal Skytt; Pedersen, Jacob Krabbe; Fode, Peder

    2012-01-01

    Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle-aged and elde......Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle.......4%-34.5%), and opposite sex (21.4%; 95% CI, 12.0%-33.4%) dizygotic twins. Despite shared childhoods, only 1 of 617 pairs was concordant with respect to lineage. Although heritability increased for S. aureus and lineage persistency, no significant heritability was detected. Conclusion. In this study, host genetic factors...

  15. Age-related decrements in bone mineral density in women over 65

    Science.gov (United States)

    Steiger, P.; Cummings, S. R.; Black, D. M.; Spencer, N. E.; Genant, H. K.

    1992-01-01

    Age-related changes in bone density contribute to the risk of fractures. To describe the relationship between age and bone mass in elderly women, we studied a large cohort of women over age 65 years who were recruited from population-based lists in four cities in the United States. Bone density in g/cm2 was measured by single-photon absorptiometry (SPA) and dual x-ray absorptiometry (DXA) at the distal and proximal radius, the calcaneus, the lumbar spine, and the proximal femur. Centralized data collection was used to control data quality and consistency. We found a strong inverse relationship between bone density and age for most sites. Decrements in bone density between women aged 65-69 years and women 85 years and older exceeded 16% in all regions except the spine, where the difference between the two age groups was 6%. Ward's triangle and the calcaneus exhibited the largest decrements, with 26 and 21%, respectively. The estimates of annual changes in bone mineral density by linear regression at sites other than the spine ranged from -0.82% at the femoral neck and trochanter to -1.30% at Ward's triangle. Correlations between the different regions ranged from r = 0.51 between the proximal radius and Ward's triangle to r = 0.66 between the distal radius and calcaneus. We conclude that the inverse relationship between age and bone mass measured by absorptiometry techniques in white women continues into the ninth decade of life. The relationship is strongest for bone density of Ward's triangle and the calcaneus and weakest for the spine.

  16. Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific.

    Directory of Open Access Journals (Sweden)

    Greta S Aeby

    2011-02-01

    Full Text Available Growth anomalies (GAs are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA (n = 304 surveys and Porites growth anomalies (PGA (n = 602 surveys from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies found on different host genera (Acropora vs. Porites. As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

  17. Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific

    Science.gov (United States)

    Aeby, Greta S.; Williams, Gareth J.; Franklin, Erik C.; Haapkyla, Jessica; Harvell, C. Drew; Neale, Stephen; Page, Cathie A.; Raymundo, Laurie; Vargas-Angel, Bernardo; Willis, Bette L.; Work, Thierry M.; Davy, Simon K.

    2011-01-01

    Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

  18. Ecology of Meimuna mongolica (Hemiptera: Cicadidae) Nymphs: Instars, Morphological Variation, Vertical Distribution and Population Density, Host-Plant Selection, and Emergence Phenology

    Science.gov (United States)

    Li, Qinglong; Yang, Mingsheng; Liu, Yunxiang; Wei, Cong

    2015-01-01

    The cicada Meimuna mongolica (Distant) (Hemiptera: Cicadidae) is one of the most important pests of economic forest in Guanzhong Plain of Shaanxi Province, China. Information about ecological characteristics and some sustainable control measures of this species is urgently required for its control. In this study, nymphal instars, morphological variation, vertical distribution, and population density in soil, and emergence phenology of nymphs of M. mongolica on three main host plants (Pinus tabuliformis Carr., Populus tomentosa Carr., and Pyrus xerophila Yü) were studied, based on combined morphological and molecular identification, investigation of the first-instar nymphs hatched from eggs and others excavated from soil, and investigation of exuviae in the adult emergence period. Five nymphal instars of M. mongolica were redetermined according to the distribution plots of the head capsule widths of the nymphs. Nymphs of third and fourth instars showed morphological variation, which is closely related to host-plant association. The mean densities of nymphs in soil under the three host plants were significantly different, indicating a distinct host preference. The nymphs could extend their distribution from the 0–10 cm soil layer to the 51–60 cm soil layer underground but not beyond 60 cm soil layer under all the three host plants. The 21–30 cm soil layer under all the three host plants has the highest nymphal population density. The sex ratio of the entire population was nearly 50:50, but males dominated in the early half of the duration of the emergence. These ecological characteristics of M. mongolica could provide important information for sustainable control measures.

  19. Research Strategies to Reduce Tick Densities and the Risk of Tick-borne Disease Transmission through Host-Targeted Control

    Science.gov (United States)

    While white-tailed deer are not reservoir hosts for the Lyme disease agent, Borrelia burgdorferi, they are the keystone host animal on which adult female blacklegged ticks engorge on blood that is essential to production of tick eggs and completion of the life cycle. This session explores current re...

  20. Association of age and macular pigment optical density using dual-wavelength autofluorescence imaging.

    Science.gov (United States)

    Lima, Verônica Castro; Rosen, Richard B; Prata, Tiago Santos; Dorairaj, Syril; Spielberg, Leigh; Maia, Mauricio; Sallum, Juliana M

    2013-01-01

    Several lines of evidence suggest that macular pigment may play a protective role against age-related macular degeneration, but the influence of age on macular pigment density levels remains unclear. This study was designed to investigate the relationship between age and the normal distribution of macular pigment optical density (MPOD) values surrounding the fovea. Consecutive healthy subjects with no evidence of ocular disease were enrolled in this study. After inclusion, MPOD values were measured at specific eccentricities (0.5, 1, and 2 degrees) from the foveal center using a dual-wavelength autofluorescence method employing a modified confocal scanning laser ophthalmoscope. Whenever both eyes were eligible, one was randomly selected for analysis. The correlation between age and MPOD values was investigated using regression analysis. Thirty subjects (30 eyes) were included (mean age 48.6 ± 16.4 [range 23-77] years). Significant differences were found between MPOD values measured at 0.5, 1, and 2 degrees from the center of the fovea (0.49 ± 0.12 density units, 0.37 ± 0.11 density units, and 0.13 ± 0.05 density units, respectively, P < 0.05). Significant correlations between age and MPOD values at 0.5 and 1 degree were found (P ≤ 0.02). Values measured at 2 degrees did not correlate significantly with age (P = 0.06). In healthy subjects, MPOD values were highest near the foveal center. These values appeared to increase during adulthood (peak at 45-50 years), followed by a gradual reduction after 60 years of age.

  1. The effects of host age and spatial location on bacterial community composition in the English Oak tree (Quercus robur).

    Science.gov (United States)

    Meaden, S; Metcalf, C J E; Koskella, B

    2016-04-27

    Drivers of bacterial community assemblages associated with plants are diverse and include biotic factors, such as competitors and host traits, and abiotic factors, including environmental conditions and dispersal mechanisms. We examine the roles of spatial distribution and host size, as an approximation for age, in shaping the microbiome associated with Quercus robur woody tissue using culture-independent 16S rRNA gene amplicon sequencing. In addition to providing a baseline survey of the Q. robur microbiome, we screened for the pathogen of acute oak decline. Our results suggest that age is a predictor of bacterial community composition, demonstrating a surprising negative correlation between tree age and alpha diversity. We find no signature of dispersal limitation within the Wytham Woods plot sampled. Together, these results provide evidence for niche-based hypotheses of community assembly and the importance of tree age in bacterial community structure, as well as highlighting that caution must be applied when diagnosing dysbiosis in a long-lived plant host. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Age dependent mineral density in the bones of inhabitants of Karelia

    Directory of Open Access Journals (Sweden)

    I. G. Pashkova

    2013-01-01

    Full Text Available Analysis of the age changes of mineral density in the lumbar vertebrae was carried out in 929 people (740 women and 189 men at the age of 20 to 87 years, living in Karelia. Bone mineral density was evaluated by dual xray absorptiometry. In the women and in the men the spine bone mineralization peak was seen at the age of 22. The peak mineral density values were 5 % lower in the men and 1.6 % in the women in comparison with the data of the densitometer base. Considerable decrease of the bone mineral density in the vertebrae in the women began at the age of 41–45 years, and in the men – at the age of 51–55 years. Demineralization of the vertebrae in 75 year old women was 20 %, in the men it was 11.1 %, and in 81–87 year old women – 25.2 %.

  3. Density-dependent sex ratio and sex-specific preference for host traits in parasitic bat flies.

    Science.gov (United States)

    Szentiványi, Tamara; Vincze, Orsolya; Estók, Péter

    2017-08-29

    Deviation of sex ratios from unity in wild animal populations has recently been demonstrated to be far more prevalent than previously thought. Ectoparasites are prominent examples of this bias, given that their sex ratios vary from strongly female- to strongly male-biased both among hosts and at the metapopulation level. To date our knowledge is very limited on how and why these biased sex ratios develop. It was suggested that sex ratio and sex-specific aggregation of ectoparasites might be shaped by the ecology, behaviour and physiology of both hosts and their parasites. Here we investigate a highly specialised, hematophagous bat fly species with strong potential to move between hosts, arguably limited inbreeding effects, off-host developmental stages and extended parental care. We collected a total of 796 Nycteribia kolenatii bat flies from 147 individual bats using fumigation and subsequently determined their sex. We report a balanced sex ratio at the metapopulation level and a highly variable sex ratio among infrapopulations ranging from 100% male to 100% female. We show that infrapopulation sex ratio is not random and is highly correlated with infrapopulation size. Sex ratio is highly male biased in small and highly female biased in large infrapopulations. We show that this pattern is most probably the result of sex-specific preference in bat flies for host traits, most likely combined with a higher mobility of males. We demonstrate that female bat flies exert a strong preference for high host body condition and female hosts, while the distribution of males is more even. Our results suggest that locally biased sex ratios can develop due to sex-specific habitat preference of parasites. Moreover, it is apparent that the sex of both hosts and parasites need to be accounted for when a better understanding of host-parasite systems is targeted.

  4. Age as a predictive factor of mammographic breast density in Jamaican women

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Deanne; Reid, Marvin; James, Michael

    2002-06-01

    AIM: We sought to determine the relationship between age, and other clinical characteristics such as parity, oestrogen use, dietary factors and menstrual history on breast density in Jamaican women. METHODS AND MATERIALS: A retrospective study was done of 891 patients who attended the breast imaging unit. The clinical characteristics were extracted from the patient records. Mammograms were assessed independently by two radiologists who were blinded to the patient clinical characteristics. Breast densities were assigned using the American College of Radiology (ACR) classification. RESULTS: The concordance between the ACR classification of breast density between the two independent radiologists was 92% with k = 0.76 (SE = 0.02, P < 0.001). Women with low breast density were heavier (81.3 {+-} 15.5 kg vs 68.4 {+-} 14.3 kg,P < 0.0001, mean {+-} standard deviation (SD)) and more obese (body mass index (BMI), 30.3 {+-} 5.8 kg m{sup -2} vs 26.0 {+-} 5.2 kg m{sup -2}, P < 0.0001). Mammographic breast density decreased with age. The age adjusted odds ratios (ORs) for predictors significantly related to high breast density were parity, OR = 0.79 (95%CI:0.71, 0.88), weight, OR = 0.92 (95% CI:0.91, 0.95), BMI, OR = 0.83 (95% CI:0.78, 0.89), menopause, OR = 0.51 (95% CI:0.36, 0.74) and a history of previous breast surgery, OR 1.6 (95% CI:1.1, 2.3). CONCLUSION: The rate decline of breast density with age in our population was influenced by parity and body composition. Soares, D. et al. (2002)

  5. Association of age and macular pigment optical density using dual-wavelength autofluorescence imaging

    Directory of Open Access Journals (Sweden)

    Lima VC

    2013-04-01

    Full Text Available Verônica Castro Lima,1,2 Richard B Rosen,1,3 Tiago Santos Prata,2 Syril Dorairaj,4 Leigh Spielberg,1 Mauricio Maia,2 Juliana M Sallum21Retina Service, Department of Ophthalmology, The New York Eye and Ear Infirmary, New York, NY, 2Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil; 3New York Medical College, New York, NY, 4Department of Ophthalmology, Mayo Clinic, Jacksonville, FL, USABackground: Several lines of evidence suggest that macular pigment may play a protective role against age-related macular degeneration, but the influence of age on macular pigment density levels remains unclear. This study was designed to investigate the relationship between age and the normal distribution of macular pigment optical density (MPOD values surrounding the fovea.Methods: Consecutive healthy subjects with no evidence of ocular disease were enrolled in this study. After inclusion, MPOD values were measured at specific eccentricities (0.5, 1, and 2 degrees from the foveal center using a dual-wavelength autofluorescence method employing a modified confocal scanning laser ophthalmoscope. Whenever both eyes were eligible, one was randomly selected for analysis. The correlation between age and MPOD values was investigated using regression analysis.Results: Thirty subjects (30 eyes were included (mean age 48.6 ± 16.4 [range 23–77] years. Significant differences were found between MPOD values measured at 0.5, 1, and 2 degrees from the center of the fovea (0.49 ± 0.12 density units, 0.37 ± 0.11 density units, and 0.13 ± 0.05 density units, respectively, P < 0.05. Significant correlations between age and MPOD values at 0.5 and 1 degree were found (P ≤ 0.02. Values measured at 2 degrees did not correlate significantly with age (P = 0.06.Conclusion: In healthy subjects, MPOD values were highest near the foveal center. These values appeared to increase during adulthood (peak at 45–50 years, followed by a gradual reduction

  6. Impact of Adult Weight, Density, and Age on Reproduction of Tenebrio molitor (Coleoptera: Tenebrionidae)

    Science.gov (United States)

    The impact of adult weight, age, and density on reproduction of Tenebrio molitor L. (Coleoptera: Tenebrionidae) was studied. The impact of adult weight on reproduction was determined in two ways: 1) counting the daily progeny of individual adult pairs of known weight and analyzing the data with line...

  7. Language and Ageing--Exploring Propositional Density in Written Language--Stability over Time

    Science.gov (United States)

    Spencer, Elizabeth; Craig, Hugh; Ferguson, Alison; Colyvas, Kim

    2012-01-01

    This study investigated the stability of propositional density (PD) in written texts, as this aspect of language shows promise as an indicator and as a predictor of language decline with ageing. This descriptive longitudinal study analysed written texts obtained from the Australian Longitudinal Study of Women's Health in which participants were…

  8. Alternative male mating behaviour in the two-spotted spider mite: dependence on age and density

    NARCIS (Netherlands)

    Sato, Y.; Sabelis, M.W.; Egas, M.

    2014-01-01

    Highlights • We investigated alternative male mating behaviour in the two-spotted spider mite. • We found no differences between genetic lines of fighting and sneaking behaviour. • The proportion of sneaker males changed with male density and with male age. • In competition with old males, young

  9. Arthropod density and biomass in longleaf pines: effects of pine age and hardwood midstory

    Science.gov (United States)

    Richard N. Conner; Christopher S. Collins; Daniel Saenz; Toni Trees; Richard R. Schaefer; D. Craig Rudolph

    2004-01-01

    During a 2-year study we examined arthropod communities (density and biomass) on longleaf pines (Pinus palustris) in eastern Texas during spring, summer, and winter on trees in 3 age classes: 40-50, 60-70, and 130-1 50 years, as a potential food source for the red-cockaded woodpecker (Picoides borealis). We also examined arthropod...

  10. Cultural Orientation in Asian American Adolescents: Variation by Age and Ethnic Density

    Science.gov (United States)

    Ying, Yu-Wen; Han, Meekyung; Wong, Sandra L.

    2008-01-01

    The study assessed variation in cultural orientation among Asian American adolescents by age and ethnic density in the community. A total of 128 students at a public high school in Oakland, California, participated in the study. Of these early and middle adolescents, 86 were Chinese American and 42 were Southeast Asian American. They completed the…

  11. Age-specific interaction between the parasitoid, Encarsia formosa and its host, the silverleaf whitefly, Bemisia tabaci (Strain B

    Directory of Open Access Journals (Sweden)

    Jing S. Hu

    2003-08-01

    Full Text Available The effect of hostage, the instar of Bemisia tabaci (Gennadius parasitized, on the growth and development of Encarsia formosa (Gahan was studied. E. formosa was able to parasitize and complete its life cycle no matter which instar of B. tabaci (Strain B, [also identified as B. argentifolii (Bellows and Perring], was provided for oviposition, but parasitoid development was significantly slower when 1st or 2nd instar B. tabaci rather than 3rd or 4th instars were parasitized. Host age influenced the day on which E. formosa nymphs hatching from eggs was first observed. Mean embryonic development was significantly longer when 1st (5.4 days rather than 2nd, 3rd or 4th instars (4.1, 3.4 and 3.5 days, respectively were parasitized. The duration of the 1st instar parasitoid and the pupa, but not the 2nd or 3rd instar parasitoid, were also significantly greater when 1st instars were parasitized than when older host instars were parasitized. Interestingly, no matter which instar was parasitized, the parasitoid did not molt to the 3rd instar until the 4th instar host had reached a depth of about 0.23 mm (Stage 4-5 and had initiated the nymphal-adult molt and adult development. Histological studies revealed that whitefly eye and wing structures had either disintegrated or were adult in nature whenever a 3rd instar parasitoid was present. It appears, then, that the molt of the parasitoid to its last instar is associated with the host whitefly's nymphal-adult molt. However, the initiation of the host's final molt, while a prerequisite for the parasitoid's 2nd-3rd instar molt, did not necessarily trigger this molt. In contrast to its significant effect on various aspects of parasitoid development, host instar did not significantly influence the mean size of the parasitoid larva, pupa, or adult. Larval and pupal length and adult head width were similar for all parasitoids, regardless of which host instar was parasitized as was adult longevity. Adult parasitoid

  12. Physical activity and bone mineral density in Italian middle-aged women

    International Nuclear Information System (INIS)

    Bidoli, Ettore; Schinella, Domenico; Franceschi, Silvia

    1998-01-01

    Osteoporosis is a major health issue in postmenopausal women on account of the association between low bone mineral density and fractures. A role of physical activity in the prevention and treatment of low bone mineral density is possible but still unclear. The relationship between low spine bone mineral density measured by means of dual photon absorptiometry at lumbar spines, and levels of past and recent physical activity has been assessed by means of a population-based screening study carried out on 1373 women (age 40-64 years) in the North-East of Italy. Physical activity at work and in leisure time was investigated for three specific periods of life: at age 12, between 15 and 19 years (during bone formative years), and in the recent years prior to the interview (30-39 or 50-59 years). Data were analysed comparing low versus high bone mineral density tertile (i.e., 458 and 461 women, respectively), after controlling for other known contributory factors in the development of osteoporosis. A positive association emerged with leisure time physical activity, with significant trends at age 15-19 (odds ratio (OR) for low versus high tertile of leisure time activity: 1.4, 95% confidence interval (CI): 0.8-2.4) and at most recent age (OR: 1.7, 95% CI: 1.1-2.6). Risk trends with occupational physical activity were less clear and non-statistically significant. The present Southern European cross-sectional study lends further support to the possibility that past and recent physical activity helps increasing bone mineral density in middle-aged women. Although the most beneficial type and intensity level of exercise has yet to be determined, the present results provide further evidence that participation in even moderate exercise programs should be encouraged

  13. Best Host Age of Anastrepha obliqua (Diptera: Tephritidae) for Multiplication of Four Native Parasitoids from the Americas

    Science.gov (United States)

    Poncio, S; Montoya, P; Cancino, J; Nava, D E

    2018-01-01

    Abstract The success of the mass rearing of parasitoids is directly related to host quality, and it requires selecting the best biological host age to ensure the optimal performance of the parasitoids released into the field. The larval development of the parasitoids Utetes anastrephae (Viereck) (Hymenoptera: Braconidae) and Odontosema anastrephae Borgmeier (Hymenoptera: Eucoilidae) and the pupal development of the parasitoids Coptera haywardi (Ogloblin) (Hymenoptera: Diapriidae) and Dirhinus sp. (Hymenoptera: Chalcididae) on the native host Anastrepha obliqua (Macquart) (Diptera: Tephritidae) in different larvae and pupae ages were investigated under laboratory conditions. Not all parasitoid species developed with the same efficiency in immature individuals of A. obliqua; U. anastrephae and C. haywardi showed the higher parasitism rates. The emergence and parasitism of U. anastrephae were equal using larvae from 5 to 8 d, while C. haywardi reared in 1- to 8-d-old pupae showed higher averages of parasitism. These results suggest that native parasitoids can be used to strengthen the implementation of biological control projects against A. obliqua, a pest of economic importance in South America.

  14. Osteoprotegerin autoantibodies do not predict low bone mineral density in middle-aged women.

    Science.gov (United States)

    Vaziri-Sani, Fariba; Brundin, Charlotte; Agardh, Daniel

    2017-12-01

    Autoantibodies against osteoprotegerin (OPG) have been associated with osteoporosis. The aim was to develop an immunoassay for OPG autoantibodies and test their diagnostic usefulness of identifying women general population with low bone mineral density. Included were 698 women at mean age 55.1 years (range 50.4-60.6) randomly selected from the general population. Measurement of wrist bone mineral density (g/cm 2 ) was performed of the non-dominant wrist by dual-energy X-ray absorptiometry (DXA). A T-score density. Measurements of OPG autoantibodies were carried by radiobinding assays. Cut-off levels for a positive value were determined from the deviation from normality in the distribution of 398 healthy blood donors representing the 99.7th percentile. Forty-five of the 698 (6.6%) women were IgG-OPG positive compared with 2 of 398 (0.5%) controls ( p  density between IgG-OPG positive (median 0.439 (range 0.315-0.547) g/cm 2 ) women and IgG-OPG negative (median 0.435 (range 0.176-0.652) g/cm 2 ) women ( p  = 0.3956). Furthermore, there was neither a correlation between IgG-OPG levels and bone mineral density (r s  = 0.1896; p  = 0.2068) nor T-score (r s  = 0.1889; p  = 0.2086). Diagnostic sensitivity and specificity of IgG-OPG for low bone mineral density were 5.7% and 92.9%, and positive and negative predictive values were 7.4% and 90.8%, respectively. Elevated OPG autoantibody levels do not predict low bone mineral density in middle-aged women selected from the general population.

  15. Strong host-feeding preferences of the vector Triatoma infestans modified by vector density: implications for the epidemiology of Chagas disease.

    Directory of Open Access Journals (Sweden)

    Ricardo E Gürtler

    2009-05-01

    Full Text Available Understanding the factors that affect the host-feeding preferences of triatomine bugs is crucial for estimating transmission risks and predicting the effects of control tactics targeting domestic animals. We tested whether Triatoma infestans bugs prefer to feed on dogs vs. chickens and on dogs vs. cats and whether vector density modified host choices and other vital rates under natural conditions.Two host choice experiments were conducted in small caged huts with two rooms between which bugs could move freely. Matched pairs of dog-chicken (six and dog-cat (three were assigned randomly to two levels of vector abundance and exposed to starved bugs during three nights. Bloodmeals from 1,160 bugs were tested by a direct enzyme-linked immunosorbent assay.Conditional logistic regression showed that dogs were highly preferred over chickens or cats and that vector density modified host-feeding choices. The relative risk of a bug being blood-engorged increased significantly when it fed only on dog rather than chicken or cat. Bugs achieved higher post-exposure weight at higher vector densities and successive occasions, more so if they fed on a dog rather than on a cat.Our findings strongly refute the hypothesis that T. infestans prefers to blood-feed on chickens rather than dogs. An increase in dog or cat availability or accessibility will increase the rate of bug feeding on them and exert strong non-linear effects on R(0. When combined with between-dog heterogeneities in exposure, infection, and infectiousness, the strong bug preference for dogs can be exploited to target dogs in general, and even the specific individuals that account for most of the risk, with topical lotions or insecticide-impregnated collars to turn them into baited lethal traps or use them as transmission or infestation sentinels based on their immune response to Trypanosoma cruzi or bug salivary antigens.

  16. Magnetic resonance fiber density mapping of age-related white matter changes

    International Nuclear Information System (INIS)

    Stadlbauer, Andreas; Ganslandt, Oliver; Salomonowitz, Erich; Buchfelder, Michael; Hammen, Thilo; Bachmair, Johanna; Eberhardt, Knut

    2012-01-01

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm 3 isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  17. Magnetic resonance fiber density mapping of age-related white matter changes

    Energy Technology Data Exchange (ETDEWEB)

    Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Ganslandt, Oliver [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Salomonowitz, Erich [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Buchfelder, Michael [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Hammen, Thilo [Department of Neurology, Epilepsy Center, University of Erlangen-Nuremberg, Schwabachanlage 6, D-90429 Erlangen (Germany); Bachmair, Johanna [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Eberhardt, Knut [Krankenhaus Schloss Werneck, MRT-Kompetenzzentrum, Balthasar-Neumann-Platz 1, D-97440 Werneck (Germany)

    2012-12-15

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm{sup 3} isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  18. Age, gender, and race/ethnic differences in total body and subregional bone density.

    Science.gov (United States)

    Looker, A C; Melton, L J; Harris, T; Borrud, L; Shepherd, J; McGowan, J

    2009-07-01

    Total body bone density of adults from National Health and Nutrition Examination Survey (NHANES) 1999-2004 differed as expected for some groups (men>women and blacks>whites) but not others (whites>Mexican Americans). Cross-sectional age patterns in bone mineral density (BMD) of older adults differed at skeletal sites that varied by degree of weight-bearing. Total body dual-energy X-ray absorptiometry (DXA) data offer the opportunity to compare bone density of demographic groups across the entire skeleton. The present study uses total body DXA data (Hologic QDR 4500A, Hologic, Bedford MA, USA) from the NHANES 1999-2004 to examine BMD of the total body and selected skeletal subregions in a wide age range of adult men and women from three race/ethnic groups. Total body, lumbar spine, pelvis, right leg, and left arm BMD and lean mass from 13,091 adults aged 20 years and older were used. The subregions were chosen to represent sites with different degrees of weight-bearing. Mean BMD varied in expected ways for some demographic characteristics (men>women and non-Hispanic blacks>non-Hispanic whites) but not others (non-Hispanic whites>Mexican Americans). Differences in age patterns in BMD also emerged for some characteristics (sex) but not others (race/ethnicity). Differences in cross-sectional age patterns in BMD and lean mass by degree of weight-bearing in older adults were observed for the pelvis, leg, and arm. This information may be useful for generating hypotheses about age, race, and sex differences in fracture risk in the population.

  19. Effects of selfsuperparasitism and host age on fitness-correlated traits in the solitary endoparasitoid wasp Meteorus pulchricornis

    Science.gov (United States)

    Zhang, Bo; Li, Baoping; Meng, Ling

    2014-01-01

    Abstract The domed fitness functions are suggested to describe developmental patterns of progeny parasitoids in relation to host age at oviposition in solitary koinobint parasitoids that are engaged in single parasitism, but few studies have investigated the applicability of the functions as related to superparasitism. The present study was designed to compare fitness functions between single parasitism and superparasitism by examining developmental patterns of Meteorus pulchricornis (Wesmael) (Hymneoptera: Braconidae) progeny in relation to the beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae), either singly parasitized or self-superparasitized as second–fifth instar larvae. Selfsuperparasitism caused deleterious effects on the fitness-related traits of parasitoid progeny, as demonstrated by a prolonged egg-to-adult emergence time, a smaller body size, and shorter longevity of the emerging adults, and decreased survival to adult emergence. While the domed fitness function was detected for development time, survival, adult body size, and longevity in relation to host larvae that were singly parasitized, the function was observed only for progeny survival in relation to host larvae that were self-superparasitized. This study suggests that developmental fitness functions with selfsuperparasitism can deviate from those with single parasitism in solitary koinobiont parasitoids. PMID:25201512

  20. Effects of self-superparasitism and host age on fitness-correlated traits in the solitary endoparasitoid wasp Meteorus pulchricornis.

    Science.gov (United States)

    Zhang, Bo; Li, Baoping; Meng, Ling

    2014-01-01

    The domed fitness functions are suggested to describe developmental patterns of progeny parasitoids in relation to host age at oviposition in solitary koinobint parasitoids that are engaged in single parasitism, but few studies have investigated the applicability of the functions as related to superparasitism. The present study was designed to compare fitness functions between single parasitism and superparasitism by examining developmental patterns of Meteorus pulchricornis (Wesmael) (Hymneoptera: Braconidae) progeny in relation to the beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae), either singly parasitized or self-superparasitized as second-fifth instar larvae. Self-superparasitism caused deleterious effects on the fitness-related traits of parasitoid progeny, as demonstrated by a prolonged egg-to-adult emergence time, a smaller body size, and shorter longevity of the emerging adults, and decreased survival to adult emergence. While the domed fitness function was detected for development time, survival, adult body size, and longevity in relation to host larvae that were singly parasitized, the function was observed only for progeny survival in relation to host larvae that were self-superparasitized. This study suggests that developmental fitness functions with self-superparasitism can deviate from those with single parasitism in solitary koinobiont parasitoids.

  1. Aberrant Bone Density in Aging Mice Lacking the Adenosine Transporter ENT1

    Science.gov (United States)

    Hinton, David J.; McGee-Lawrence, Meghan E.; Lee, Moonnoh R.; Kwong, Hoi K.; Westendorf, Jennifer J.; Choi, Doo-Sup

    2014-01-01

    Adenosine is known to regulate bone production and resorption in humans and mice. Type 1 equilibrative nucleoside transporter (ENT1) is responsible for the majority of adenosine transport across the plasma membrane and is ubiquitously expressed in both humans and mice. However, the contribution of ENT1-mediated adenosine levels has not been studied in bone remodeling. With the recent identification of the importance of adenosine signaling in bone homeostasis, it is essential to understand the role of ENT1 to develop novel therapeutic compounds for bone disorders. Here we examined the effect of ENT1 deletion on bone density using X-ray, dual energy X-ray absorptiometry and micro-computerized tomography analysis. Our results show that bone density and bone mineral density is reduced in the lower thoracic and lumbar spine as well as the femur of old ENT1 null mice (>7 months) compared to wild-type littermates. Furthermore, we found increased mRNA expression of tartrate-resistant acid phosphatase (TRAP), an osteoclast marker, in isolated long bones from 10 month old ENT1 null mice compared to wild-type mice. In addition, aged ENT1 null mice displayed severe deficit in motor coordination and locomotor activity, which might be attributed to dysregulated bone density. Overall, our study suggests that ENT1-regulated adenosine signaling plays an essential role in lumbar spine and femur bone density. PMID:24586402

  2. Aberrant bone density in aging mice lacking the adenosine transporter ENT1.

    Directory of Open Access Journals (Sweden)

    David J Hinton

    Full Text Available Adenosine is known to regulate bone production and resorption in humans and mice. Type 1 equilibrative nucleoside transporter (ENT1 is responsible for the majority of adenosine transport across the plasma membrane and is ubiquitously expressed in both humans and mice. However, the contribution of ENT1-mediated adenosine levels has not been studied in bone remodeling. With the recent identification of the importance of adenosine signaling in bone homeostasis, it is essential to understand the role of ENT1 to develop novel therapeutic compounds for bone disorders. Here we examined the effect of ENT1 deletion on bone density using X-ray, dual energy X-ray absorptiometry and micro-computerized tomography analysis. Our results show that bone density and bone mineral density is reduced in the lower thoracic and lumbar spine as well as the femur of old ENT1 null mice (>7 months compared to wild-type littermates. Furthermore, we found increased mRNA expression of tartrate-resistant acid phosphatase (TRAP, an osteoclast marker, in isolated long bones from 10 month old ENT1 null mice compared to wild-type mice. In addition, aged ENT1 null mice displayed severe deficit in motor coordination and locomotor activity, which might be attributed to dysregulated bone density. Overall, our study suggests that ENT1-regulated adenosine signaling plays an essential role in lumbar spine and femur bone density.

  3. Analysis and comparison of breast density according to age on mammogram between Korean and Western women

    International Nuclear Information System (INIS)

    Kim, Seung Hyung; Kim, Mi Hye; Oh, Ki Keun

    2000-01-01

    To compare changes in breast parenchymal density among diverse age groups in asymptomatic Korean women with those of Western women, and to evaluate the effect of different patterns of breast parenchymal density on the sensitivity of screening mammography in Korean women. We analyzed the distribution of breast parenchymal density among diverse age groups in 823 asymptomatic Korean women aged 30-64 who underwent screening mammography between January and December 1998. On the basis of ACR BI-RADS breast composition, four density patterns were designated: patterns 1 and 2 related to fatty mammograms, and patterns 3 and 4 to dense mammograms. We compared the results with those for western women. In Korean women, the frequency of dense mammogram was 88.1% (30-34 years old), 91.1% (35-39), 78.3% (40-44), 61.1% (45-49), 30.1% (50-54), 21.1% (55-59), and 7.0% (60-64). Korean women in their 40s thus showed a higher frequency of dense mammograms, but this frequency decreased abruptly between the ages of 40 and 54. In Western women, however, there was little difference between 40 and 54-year-olds: the figures were 47.2% (40-44 years), 44.8% (45-49), and 44.4% (50-54). Because the frequency of their dense mammograms shows little change between Western women in their forties and in their fifties, it is clear that between these two age groups, mammographic sensitivity is only slightly different. Because the frequency of dense mammograms is much greater among Korean women in their forties than among Western women of the same age, and among korean women this frequency decreases abruptly, it appears, however, that the mammographic sensitivity of korean women is less among those in their forties than among those in their fifties. It is therefore thought that mammography combined with ultrasonography may increase screening sensitivity among Korean women under 50, who have a relatively higher incidence of breast cancer in the younger age groups than do Western women. (author)

  4. The role of age, environmental and occupational factors on semen density.

    Science.gov (United States)

    Łepecka-Klusek, Celina; Wdowiak, Artur; Pilewska-Kozak, Anna B; Syty, Kinga; Jakiel, Grzegorz

    2011-01-01

    The problem of effect of the environment on human reproduction has been in the focus of researchers' interest for many years. To examine the relationship between semen density in males with reproduction problems, and their age, living and working conditions. The study covered 224 males with reproduction problems. The study had a prospective character and was conducted in three stages - the first stage was carried out using the questionnaire devised by the authors; the second and the third stages consisted in the examination and evaluation of male semen density. Statistical analysis was used to search for the relationship between these groups and variables adopted in the study, i.e. age, occupation performed, place of residence, self-reported housing conditions and material standard, reporting by the males in the study of arduousness of work or health hazards perceived by the males examined, and duration of employment in such conditions. The males in the study were divided into three groups according to their semen density. Group I (20 × 10(6) mln/ml or more) included 62 (27.7%) respondents, Group II (below 20 × 10(6) mln/ml) covered 121 males (54.0%), while Group III (only single spermatozoa or none) - 41 males (18.3%). Male semen density are significantly correlated with men's ages and jobs as well as the general evaluations of the jobs held by the men (p0.05). The results obtained encourage continuation of the studies and cover a larger group of males with reproduction problems.

  5. The Relationship of Age, Body Mass Index, and Individual Habit to Bone Mineral Density in Adults

    International Nuclear Information System (INIS)

    Park, Soung Ock; Lee, In Ja; Shin, Gwi Soon

    2008-01-01

    We studied the change of bone mineral density (BMD) by age, body mass index (BMI), coffee, carbonated drink, alcohol, smoking, and exercise in adults who checked in health center. The number of study subjects was total 268 persons (women of 136 persons and men of 132 persons). The BMD was determined in lumbar spine and femoral neck by dual energy x-ray absorptiometry. And we got some results as below : 1. In women, mean body height was , mean body weight was 155.8±6.0 cm, and mean BMI was 56.8±7.9 kg. In men, mean body height was 169.1±6.0 cm, mean body weight was 69.0±9.5 kg, and mean BMI was 24.1±2.7 kg/m 2 . 2. BMD decreased as age increased, and the age was the most determinant factor for BMD (p<0.01). Women's BMD decreased rapidly in the groups aged ≥50s, while men's BMD decreased gradually with age. In addition, for both sex, lower BMD was measured in lumbar spine than in femoral neck. 3. BMD increased in high BMI, and BMD with BMI increased distinctly in the group aged 50s. But their relationship was not significant. 4. In view of the distribution by three BMD categories, women's BMD was mostly normal in the groups aged ≥40s but the rate of osteopenia and osteoporosis was similar in the group aged 50s, and the rate of osteoporosis was the highest in the groups aged 60s and 70s. Men's BMD was mostly normal through all groups except the group aged 70s. 5. Coffee and carbonated drink were not influenced in BMD. But alcohol-drinking group showed higher BMD than non-drinking group, and alcohol was statistically significant determinant for BMD (p<0.05). Smoking and exercise were not statistically significant determinant of BMD.

  6. The effect of aging on the critical current density in superconducting Nb-Ti-Zr alloys

    International Nuclear Information System (INIS)

    Ishida, Fumihiko; Doi, Toshio

    1979-01-01

    The effect of aging temperature, cold-reduction prior to aging, O 2 content and composition on the variation in the critical current density, J sub(c), by isothermal aging was investigated in heavily cold-worked Nb-Ti-Zr alloys on the Nb-Ti side. The results are summarized as follows: (1) When these alloys are aged isothermally at temperatures from 350 to 500 0 C, J sub(c) increases initially, reaches a maximum value and then decreases. Increase in J sub(c) of three orders of magnitude is possible as a result of aging. (2) The maximum value of J sub(c) on the isothermal aging curve becomes higher at a lower aging temperature, at a less cold-reduction prior to aging or with a higher O 2 content. (3) The J sub(c) of aged alloy becomes a maximum in composition containing 35 at%Nb, 60 to 65 at%Ti and less than 5 at%Zr. (4) The maximum value of J sub(c) was obtained for Nb-60.0 at%Ti-5.0 at%Zr alloy containing 1200 wt ppm O 2 , aged at 350 0 C for 330 h after 98.44% cold-reduction. The values of J sub(c) at 4.2 K were 2.4 x 10 9 A/m 2 at 5.0 T, 1.1 x 10 9 A/m 2 at 7.0 T and 3.0 x 10 8 A/m 2 at 9.0 T, respectively. The upper critical field of this specimen was 11.3 T at 4.2 K and its critical temperature was 8.6 K. (author)

  7. Utilization of outpatient services in refugee settlement health facilities: a comparison by age, gender, and refugee versus host national status

    Directory of Open Access Journals (Sweden)

    Meyer Sarah

    2011-09-01

    Full Text Available Abstract Background Comparisons between refugees receiving health care in settlement-based facilities and persons living in host communities have found that refugees have better health outcomes. However, data that compares utilization of health services between refugees and the host population, and across refugee settlements, countries and regions is limited. The paper will address this information gap. The analysis in this paper uses data from the United Nations High Commissioner of Refugees (UNHCR Health Information System (HIS. Methods Data about settlement populations and the use of outpatient health services were exported from the UNHCR health information system database. Tableau Desktop was used to explore the data. STATA was used for data cleaning and statistical analysis. Differences in various indicators of the use of health services by region, gender, age groups, and status (host national vs. refugee population were analyzed for statistical significance using generalized estimating equation models that adjusted for correlated data within refugee settlements over time. Results Eighty-one refugee settlements were included in this study and an average population of 1.53 million refugees was receiving outpatient health services between 2008 and 2009. The crude utilization rate among refugees is 2.2 visits per person per year across all settlements. The refugee utilization rate in Asia (3.5 was higher than in Africa on average (1.8. Among refugees, females have a statistically significant higher utilization rate than males (2.4 visits per person per year vs. 2.1. The proportion of new outpatient attributable to refugees is higher than that attributable to host nationals. In the Asian settlements, only 2% outpatient visits, on average, were attributable to host community members. By contrast, in Africa, the proportion of new outpatient (OPD visits by host nationals was 21% on average; in many Ugandan settlements, the proportion of outpatient

  8. Utilization of outpatient services in refugee settlement health facilities: a comparison by age, gender, and refugee versus host national status.

    Science.gov (United States)

    Weiss, William M; Vu, Alexander; Tappis, Hannah; Meyer, Sarah; Haskew, Christopher; Spiegel, Paul

    2011-09-21

    Comparisons between refugees receiving health care in settlement-based facilities and persons living in host communities have found that refugees have better health outcomes. However, data that compares utilization of health services between refugees and the host population, and across refugee settlements, countries and regions is limited. The paper will address this information gap. The analysis in this paper uses data from the United Nations High Commissioner of Refugees (UNHCR) Health Information System (HIS). Data about settlement populations and the use of outpatient health services were exported from the UNHCR health information system database. Tableau Desktop was used to explore the data. STATA was used for data cleaning and statistical analysis. Differences in various indicators of the use of health services by region, gender, age groups, and status (host national vs. refugee population) were analyzed for statistical significance using generalized estimating equation models that adjusted for correlated data within refugee settlements over time. Eighty-one refugee settlements were included in this study and an average population of 1.53 million refugees was receiving outpatient health services between 2008 and 2009. The crude utilization rate among refugees is 2.2 visits per person per year across all settlements. The refugee utilization rate in Asia (3.5) was higher than in Africa on average (1.8). Among refugees, females have a statistically significant higher utilization rate than males (2.4 visits per person per year vs. 2.1). The proportion of new outpatient attributable to refugees is higher than that attributable to host nationals. In the Asian settlements, only 2% outpatient visits, on average, were attributable to host community members. By contrast, in Africa, the proportion of new outpatient (OPD) visits by host nationals was 21% on average; in many Ugandan settlements, the proportion of outpatient visits attributable to host community members

  9. Utilization of outpatient services in refugee settlement health facilities: a comparison by age, gender, and refugee versus host national status

    Science.gov (United States)

    2011-01-01

    Background Comparisons between refugees receiving health care in settlement-based facilities and persons living in host communities have found that refugees have better health outcomes. However, data that compares utilization of health services between refugees and the host population, and across refugee settlements, countries and regions is limited. The paper will address this information gap. The analysis in this paper uses data from the United Nations High Commissioner of Refugees (UNHCR) Health Information System (HIS). Methods Data about settlement populations and the use of outpatient health services were exported from the UNHCR health information system database. Tableau Desktop was used to explore the data. STATA was used for data cleaning and statistical analysis. Differences in various indicators of the use of health services by region, gender, age groups, and status (host national vs. refugee population) were analyzed for statistical significance using generalized estimating equation models that adjusted for correlated data within refugee settlements over time. Results Eighty-one refugee settlements were included in this study and an average population of 1.53 million refugees was receiving outpatient health services between 2008 and 2009. The crude utilization rate among refugees is 2.2 visits per person per year across all settlements. The refugee utilization rate in Asia (3.5) was higher than in Africa on average (1.8). Among refugees, females have a statistically significant higher utilization rate than males (2.4 visits per person per year vs. 2.1). The proportion of new outpatient attributable to refugees is higher than that attributable to host nationals. In the Asian settlements, only 2% outpatient visits, on average, were attributable to host community members. By contrast, in Africa, the proportion of new outpatient (OPD) visits by host nationals was 21% on average; in many Ugandan settlements, the proportion of outpatient visits attributable

  10. Further studies on the relationship between platelet buoyant density and platelet age

    International Nuclear Information System (INIS)

    Boneu, B.; Vigoni, F.; Boneu, A.; Caranobe, C.; Sie, P.

    1982-01-01

    The relationship between platelet buoyant density and platelet age was investigated in eight human subjects submitted to an autologous chromium labeled platelet survival study. Platelets were isolated after isopycnic centrifugation using eight discontinuous isoosmotic stractan gradients (five subjects), or various continuous and linear isoosmolar gradients (three subjects). A paradoxical radioactivity enrichment of the dense platelets and a premature loss of radioactivity in the light platelets were observed. These results are explained by a shift of the radioactivity distribution curve toward higher densities during the 3-4 days after platelet injection, while the standard deviation of the distribution was conserved throughout the platelet life span. These results suggest that young platelets are heterogeneous and slightly less dense than the total platelet population

  11. Cell division and density of symbiotic Chlorella variabilis of the ciliate Paramecium bursaria is controlled by the host's nutritional conditions during early infection process.

    Science.gov (United States)

    Kodama, Yuuki; Fujishima, Masahiro

    2012-10-01

    The association of ciliate Paramecium bursaria with symbiotic Chlorella sp. is a mutualistic symbiosis. However, both the alga-free paramecia and symbiotic algae can still grow independently and can be reinfected experimentally by mixing them. Effects of the host's nutritional conditions against the symbiotic algal cell division and density were examined during early reinfection. Transmission electron microscopy revealed that algal cell division starts 24 h after mixing with alga-free P. bursaria, and that the algal mother cell wall is discarded from the perialgal vacuole membrane, which encloses symbiotic alga. Labelling of the mother cell wall with Calcofluor White Stain, a cell-wall-specific fluorochrome, was used to show whether alga had divided or not. Pulse labelling of alga-free P. bursaria cells with Calcofluor White Stain-stained algae with or without food bacteria for P. bursaria revealed that the fluorescence of Calcofluor White Stain in P. bursaria with bacteria disappeared within 3 days after mixing, significantly faster than without bacteria. Similar results were obtained both under constant light and dark conditions. This report is the first describing that the cell division and density of symbiotic algae of P. bursaria are controlled by the host's nutritional conditions during early infection. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  12. Tree spatial structure, host composition and resource availability influence mirid density or black pod prevalence in cacao agroforests in Cameroon.

    Science.gov (United States)

    Gidoin, Cynthia; Babin, Régis; Bagny Beilhe, Leïla; Cilas, Christian; ten Hoopen, Gerben Martijn; Bieng, Marie Ange Ngo

    2014-01-01

    Combining crop plants with other plant species in agro-ecosystems is one way to enhance ecological pest and disease regulation mechanisms. Resource availability and microclimatic variation mechanisms affect processes related to pest and pathogen life cycles. These mechanisms are supported both by empirical research and by epidemiological models, yet their relative importance in a real complex agro-ecosystem is still not known. Our aim was thus to assess the independent effects and the relative importance of different variables related to resource availability and microclimatic variation that explain pest and disease occurrence at the plot scale in real complex agro-ecosystems. The study was conducted in cacao (Theobroma cacao) agroforests in Cameroon, where cocoa production is mainly impacted by the mirid bug, Sahlbergella singularis, and black pod disease, caused by Phytophthora megakarya. Vegetation composition and spatial structure, resource availability and pest and disease occurrence were characterized in 20 real agroforest plots. Hierarchical partitioning was used to identify the causal variables that explain mirid density and black pod prevalence. The results of this study show that cacao agroforests can be differentiated on the basis of vegetation composition and spatial structure. This original approach revealed that mirid density decreased when a minimum number of randomly distributed forest trees were present compared with the aggregated distribution of forest trees, or when forest tree density was low. Moreover, a decrease in mirid density was also related to decreased availability of sensitive tissue, independently of the effect of forest tree structure. Contrary to expectations, black pod prevalence decreased with increasing cacao tree abundance. By revealing the effects of vegetation composition and spatial structure on mirids and black pod, this study opens new perspectives for the joint agro-ecological management of cacao pests and diseases at the

  13. Sarcopenia and its relationship with bone mineral density in middle-aged and elderly European men.

    Science.gov (United States)

    Verschueren, S; Gielen, E; O'Neill, T W; Pye, S R; Adams, J E; Ward, K A; Wu, F C; Szulc, P; Laurent, M; Claessens, F; Vanderschueren, D; Boonen, S

    2013-01-01

    The aim of this study was to determine the relationship between reduced muscle mass (sarcopenia) and areal bone mineral density (BMD(a)) in middle-aged and elderly community-dwelling European men. Men with sarcopenia had significantly lower BMD(a) and were more likely to have osteoporosis compared with men without sarcopenia. In men, the relationship between reduced muscle mass (sarcopenia) and BMD(a) is unclear. This study aimed to determine this relationship in middle-aged and elderly community-dwelling men. Men aged 40-79 years from the Manchester (UK) and Leuven (Belgium) cohorts of the European Male Ageing Study were invited to attend for assessment including dual-energy X-ray absorptiometry, from which appendicular lean mass (aLM), fat mass (FM) and whole-body, spine and hip BMD(a) were determined. Relative appendicular skeletal muscle mass (RASM) was calculated as aLM/height². Muscle strength was assessed in subjects from Leuven. Sarcopenia was defined by RASM at Sarcopenia in Older People (RASM at sarcopenia and osteoporosis. Six hundred seventy-nine men with a mean age of 59.6 (SD = 10.7), contributed data to the analysis; 11.9 % were sarcopenic by the conventional definition. After adjustment for age and centre, aLM, RASM and FM were positively associated with BMD(a). Men with RASM at sarcopenia were more likely to have osteoporosis compared with those with normal RASM (odds ratio = 3.0; 95 % CI = 1.6-5.8). Sarcopenia is associated with low BMD(a) and osteoporosis in middle-aged and elderly men. Further studies are necessary to assess whether maintaining muscle mass contributes to prevent osteoporosis.

  14. Predictors of Bone Mineral Density in African-American and Caucasian College Aged Women

    Directory of Open Access Journals (Sweden)

    Andrea K. Johnson

    2015-03-01

    Full Text Available Background: Research regarding risk factors and prevalence of low bone min-eral density (BMD among African-American and Caucasian college-aged wom-en are limited. The objective of this cross-sectional study was to determine if selected predictors of BMD in African-American and Caucasian college-aged women differ by race.Methods: A total of 101 local African-American (n=50 and Caucasian (n=51 females, ages 18 to 30 years, were in this study. All data were collected in the Bone Density and Body Composition Laboratory. BMD was measured using DXA technology. Race, family history of osteoporosis, BMI, current physical activity, osteoporosis knowledge, length of time on oral contraceptives, age at menarche and calcium intake were included in the multiple regression analyses with spinal and femoral BMD as dependent variables.Results: Overall, 38.6% had low spinal BMD and 7.9% had low femoral BMD. BMI (β=0.073, R2 = .148, P = .001, 95% CI [0.030, 0.116] and current physical activity (β=0.071, R2 = .148, P = .017, 95% CI [0.013, 0.129] were the only variables that were statistically significant in predicting spinal BMD. BMI (β=0.056, R2 = .13, P = .010, 95% CI [0.014, 0.098] and current physical activ-ity (β=0.078, R2 = .13, P = .007, 95% CI [0.022, 0.134] were also the only varia-bles that were statistically significant in predicting femoral BMD. Race was not a significant predictor of spinal or femoral BMD.Conclusion: It is imperative for both African-American and Caucasian women to engage in osteoporosis-preventive behaviors.

  15. The Relationship of Age, Body Mass Index, and Individual Habit to Bone Mineral Density in Adults

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soung Ock; Lee, In Ja; Shin, Gwi Soon [Dept. of Radiologic Techology, Dongnam Health College, Suwon (Korea, Republic of)

    2008-12-15

    We studied the change of bone mineral density (BMD) by age, body mass index (BMI), coffee, carbonated drink, alcohol, smoking, and exercise in adults who checked in health center. The number of study subjects was total 268 persons (women of 136 persons and men of 132 persons). The BMD was determined in lumbar spine and femoral neck by dual energy x-ray absorptiometry. And we got some results as below : 1. In women, mean body height was , mean body weight was 155.8{+-}6.0 cm, and mean BMI was 56.8{+-}7.9 kg. In men, mean body height was 169.1{+-}6.0 cm, mean body weight was 69.0{+-}9.5 kg, and mean BMI was 24.1{+-}2.7 kg/m{sup 2}. 2. BMD decreased as age increased, and the age was the most determinant factor for BMD (p<0.01). Women's BMD decreased rapidly in the groups aged {>=}50s, while men's BMD decreased gradually with age. In addition, for both sex, lower BMD was measured in lumbar spine than in femoral neck. 3. BMD increased in high BMI, and BMD with BMI increased distinctly in the group aged 50s. But their relationship was not significant. 4. In view of the distribution by three BMD categories, women's BMD was mostly normal in the groups aged {>=}40s but the rate of osteopenia and osteoporosis was similar in the group aged 50s, and the rate of osteoporosis was the highest in the groups aged 60s and 70s. Men's BMD was mostly normal through all groups except the group aged 70s. 5. Coffee and carbonated drink were not influenced in BMD. But alcohol-drinking group showed higher BMD than non-drinking group, and alcohol was statistically significant determinant for BMD (p<0.05). Smoking and exercise were not statistically significant determinant of BMD.

  16. Evidence that platelet buoyant density, but not size, correlates with platelet age in man

    International Nuclear Information System (INIS)

    Mezzano, D.; Hwang, K.; Catalano, P.; Aster, R.H.

    1981-01-01

    Following infusion of 51Cr-labeled autologous platelets into normal subjects, high-density (HD) and low-density (LD) platelet cohorts were isolated by prolonged centrifugation in isosmotic arabino-galactan (Stractan). Specific radio-activity of LD platelets declined rapidly post-infusion (T1/2 . 1.5 days), but specific radioactivity of HD platelets remained constant or increased over a 3--4-day period and gradually declined for 6--7 days thereafter. These differences were exaggerated when platelet cohorts enriched in LD or HD cells by slow centrifugation in high-density albumin were labeled and transfused. Mean survival of a platelet cohort enriched with HD cells was significantly (P less than 0.02) shorter (7.73 days) than that of a cohort enriched with LD cells (9.33) days). In normal subjects treated with aspirin, capacity for thromboxane synthesis was regained more rapidly (P less than 0.05) in LD than in HD platelets. HD and LD platelets differed only slightly in mean volume (HD platelets . 7.57 mu3, LD platelets . 6.87 mu3, 0.05 less than P less than 0.01). We believe the most logical interpretation of these findings is that under normal conditions in man, newly formed platelets are less dense on the average than total platelets and become more dense as they age in the circulation. Thus, specific radioactivity of LD platelets declines rapidly as these platelets move into a more dense compartment and are replaced by newly formed, unlabelled cells; specific radioactivity of HD platelets remains constant or increases as labelled platelets enter this compartment in numbers equal to or greater than the number leaving it at the end of their life span. The similarity in mean volumes of LD and HD platelets suggests that platelet size is unrelated to platelet age under normal conditions

  17. Multiple Comparison of Age Groups in Bone Mineral Density under Heteroscedasticity

    Directory of Open Access Journals (Sweden)

    Ahmet Sezer

    2015-01-01

    Full Text Available Osteoporosis is a silent disease because individuals may not know that they have osteoporosis until their bones become so fragile. Bone mineral density (BMD test helps to detect osteoporosis and determine the risk fractures. This study covers bone measurement data from total body dual energy X-ray absorptiometry scans for 28,454 persons who participated in the 1996–2006 National Health and Nutrition Examination Survey in USA Dual energy X-ray absorptiometry (DXA method is known as the primary method for detecting osteoporosis because of its high precision and accuracy. Testing the equality of the means of normal populations when the variances are unknown and unequal is a fundamental problem in clinical trials and biomedical research. In this study we compare age groups based upon BMD in case of unequal variance being present among the groups. First we test equality of variances among the age groups by the Hartley test. And then Scott-Smith test is used to test equality of BMD means for the age groups. Finally, Tukey-Cramer confidence intervals are constructed to detect which groups start to differ from the reference group in which BMD reaches the peak level.

  18. Oxidized low-density lipoproteins induced inflammatory process during atherogenesis with aging

    International Nuclear Information System (INIS)

    Larbi, Anis; Khalil, Abdelouahed; Douziech, Nadine; Guerard, Karl-Philippe; Fueloep, Tamas

    2005-01-01

    Atherosclerosis is a chronic disease developing through decades with two life-threatening complications: myocardial infarction and stroke. Oxidized low-density lipoproteins (oxLDL) produced by oxidative modifications of LDL in the subendothelial space have been demonstrated to be critically involved in atherogenesis through their intensive pro-inflammatory activity. Recently, it was shown that oxLDL have an apoptosis-inducing effect in T cells depending on time and degree of oxidation. The goal of the current study is to elucidate the molecular mechanisms underlying the apoptotic-inducing effects of oxLDL on T lymphocytes. T cells of young and elderly subjects were incubated for various periods of time with LDL oxidized to various degrees. The proliferation, the apoptosis, the MAPK ERK1/2 activation and the expression of the Bcl-2 protein family members were measured upon different LDL treatments. Thus, more the LDL are oxidized more they induce apoptosis and this effect is highly accentuated with aging. The oxLDL decrease the activation of the surviving molecule ERK1/2 and modulate the ratio of Bax/Bcl-2 towards a pro-apoptotic profile, which is also accentuated with aging. These results partly explain why atherosclerosis is increasing with aging concomitantly to its complications

  19. Age trends and within-site effects in wood density and radial growth in Quercus faginea mature trees

    Directory of Open Access Journals (Sweden)

    Vicelina B. Sousa

    2016-04-01

    Full Text Available Aim of the study: This paper aims to valorize the wood of Quercus faginea Lam. for high quality end uses (e.g. furniture by studying growth and quality properties using mature trees. Age trends in tree-ring width and wood density are shown and the main factors responsible for variations in tree-ring width and wood density within and between trees are investigated. Area of study: The study site is in the center of Portugal within the natural species distribution area.Material and methods: Radial samples from ten mature trees were collected at 6 heights (from base to 9.7 m and prepared for X-ray microdensity.Main results: Wood density showed high values, ranging from 0.868 g/cm3 to 0.957 g/cm3. Wood density decreased from pith to bark and with stem height. Cambial age showed a linear relationship with wood density and most of the variation in wood is explained by age. Intra-ring and axial within-tree homogeneity was good.Research highlights: Mature trees of Q. faginea showed high wood density and a high potential for high quality end uses, comparable to other oaks. Wood density is influenced by cambial age and tree-ring width. Wood quality may be improved by tree growth rates adjustment e.g. through an adequate tree stand density (e.g. thinning operations. 

  20. Age trends and within-site effects in wood density and radial growth in Quercus faginea mature trees

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, V.B.; Louzada, J.L.; Pereira, H.

    2016-07-01

    Aim of study: This paper aims to valorize the wood of Quercus faginea Lam. for high quality end uses (e.g. furniture) by studying growth and quality properties using mature trees. Age trends in tree-ring width and wood density are shown and the main factors responsible for variations in tree-ring width and wood density within and between trees are investigated. Area of study: The study site is in the center of Portugal within the natural species distribution area. Material and methods: Radial samples from ten mature trees were collected at 6 heights (from base to 9.7 m) and prepared for X-ray microdensity. Main results: Wood density showed high values, ranging from 0.868 g/cm3 to 0.957 g/cm3. Wood density decreased from pith to bark and with stem height. Cambial age showed a linear relationship with wood density and most of the variation in wood is explained by age. Intra-ring and axial within-tree homogeneity was good. Research highlights: Mature trees of Q. faginea showed high wood density and a high potential for high quality end uses, comparable to other oaks. Wood density is influenced by cambial age and tree-ring width. Wood quality may be improved by tree growth rates adjustment e.g. through an adequate tree stand density (e.g. thinning operations). (Author)

  1. Age trends and within-site effects in wood density and radial growth in Quercus faginea mature trees

    International Nuclear Information System (INIS)

    Sousa, V.B.; Louzada, J.L.; Pereira, H.

    2016-01-01

    Aim of study: This paper aims to valorize the wood of Quercus faginea Lam. for high quality end uses (e.g. furniture) by studying growth and quality properties using mature trees. Age trends in tree-ring width and wood density are shown and the main factors responsible for variations in tree-ring width and wood density within and between trees are investigated. Area of study: The study site is in the center of Portugal within the natural species distribution area. Material and methods: Radial samples from ten mature trees were collected at 6 heights (from base to 9.7 m) and prepared for X-ray microdensity. Main results: Wood density showed high values, ranging from 0.868 g/cm3 to 0.957 g/cm3. Wood density decreased from pith to bark and with stem height. Cambial age showed a linear relationship with wood density and most of the variation in wood is explained by age. Intra-ring and axial within-tree homogeneity was good. Research highlights: Mature trees of Q. faginea showed high wood density and a high potential for high quality end uses, comparable to other oaks. Wood density is influenced by cambial age and tree-ring width. Wood quality may be improved by tree growth rates adjustment e.g. through an adequate tree stand density (e.g. thinning operations). (Author)

  2. Influence of ligand-bridged substitution on the exchange coupling constant of chromium-wheels host complexes: a density functional theory study

    Science.gov (United States)

    Sadeghi Googheri, Motahare; Abolhassani, Mohammad Reza; Mirzaei, Mahmoud

    2018-05-01

    Designing and introducing novel wheel-shaped supramolecular as host complexes with new magnetic properties is the theme of the day. So in this study, new eight binuclear chromium (III) complexes, as models of real chromium-wheel host complexes, were designed based on changing of bridged-ligands and exchange coupling constants (J) of them were calculated using the broken symmetry density functional theory approach. Substitution of fluorine ligand in fluoro-bridged model [Cr2F(tBuCO2)2(H2O)2(OH)4]-1 by halogen anions (Cl-, Br- and I- ) decreased the antiferromagnetic exchange coupling between Cr(III) centres such that by going from F- to I- the J values became more positive. In the case of hydroxo-bridged model [Cr2OH(tBuCO2)2(H2O)2(OH)4]-1, replacement of hydroxyl by methoxy anion (OMe-) strengthened the antiferromagnetic property of the complex but substitution by sulfanide (SH-) and amide (NH2-) anions weakened it and changed the nature of complexes to ferromagnetic. Because of their different magnetic properties, these new investigated complexes can be suggested as interesting synthetic targets. Also, the J value changes due to ligand substitution were evaluated and it was found that the Cr-X bond strength and partial charges of involved atoms were the most effective factors on it.

  3. Increase in density and accumulation of serotonin by human aging platelets

    International Nuclear Information System (INIS)

    Mezzano, D.; Aranda, E.; Rodriguez, S.; Foradori, A.; Lira, P.

    1984-01-01

    51 Cr-labeled autologous platelets were infused into splenectomized subjects and the specific radioactivities of high-density (HD) and low-density (LD) platelet subpopulations were determined sequentially in postinfusion samples. These findings confirm previous observations in eusplenic individuals and support the hypothesis that human LD platelets are, on the average, younger than HD platelets. LD platelets contain 33.8 +/- 13.5 ng serotonin (5HT)/10(8) platelets and HD platelets 76.8 +/- 9.5 ng 5HT/10(8) platelets. Sequential measurements of 5HT in PRP platelets were performed during the recovery phase of thrombocytopenia following splenectomy in patients with idiopathic thrombocytopenic purpura (ITP), a condition associated with aging of platelets in circulation. Presplenectomy platelet 5HT was 17.7 ng/10(8) platelets and on days 1, 6, and 12 after surgery it increased to 18.1, 37.8, and 61.0 ng/10(8) platelets. When three healthy volunteers were given aspirin (500 mg/day) for up to 15 days, no significant change in the 5HT content of circulating platelets was observed. The observation that human HD platelets, enriched with older cells, contain more 5HT than LD platelets taken together with the parallel increase in platelet 5HT and age during the recovery from thrombocytopenia in ITP patients and the lack of effect of aspirin on platelet 5HT content, provides initial evidence that human platelets accumulate 5HT during their life-span in circulation

  4. Association of Renal Function and Menopausal Status with Bone Mineral Density in Middle-aged Women.

    Science.gov (United States)

    Sheng, Yueh-Hsuan; Chen, Jen-Hau; Chiou, Jeng-Min; Tsai, Keh-Sung; Lee, Yue-Yuan; Tsao, Chwen-Keng; Chen, Yen-Ching

    2015-10-13

    The association between mild renal dysfunction and bone mineral density (BMD) has not been fully explored. It is also unclear how menopausal status and the use of Chinese herb affect this association. This is a cross-sectional study that included a total of 1,419 women aged 40 to 55 years old who were recruited from the MJ Health Management Institution in Taiwan between 2009 and 2010. Spinal BMD was assessed by dual-energy X-ray absorptiometry. Renal function was assessed using estimated glomerular filtration rate (eGFR) and creatinine clearance rate (CCr). The multivariable logistic regression and general linear models were employed to assess the association between renal function and BMD. Stratification analyses were performed by menopausal status and use of Chinese herbs. Low CCr levels were significantly associated with low BMD [adjusted odds ratio (AOR) = 1.48, 95% confidence interval (CI) = 1.15-1.90]. This association was observed in premenopausal women (AOR = 1.43, 95% CI = 1.07-1.92) and in women not taking Chinese herbs (AOR = 1.48, 95% CI = 1.14-1.94). CCr is a better predictor for low BMD in middle-aged women. Menopausal status and the use of Chinese herbs also affected this association.

  5. Do Patients After Chondrosarcoma Treatment Have Age-appropriate Bone Mineral Density in the Long Term?

    Science.gov (United States)

    Hobusch, Gerhard M; Tiefenboeck, Thomas M; Patsch, Janina; Krall, Christoph; Holzer, Gerold

    2016-06-01

    In long-term survivors of osteosarcoma and Ewing sarcoma treated with the addition of radio- and chemotherapy, low bone mineral density (BMD) and fractures have been observed, presumably resulting from these adjuvants. Because patients with chondrosarcoma usually are not treated with conventional adjuvant treatment, observation of low BMD in patients with chondrosarcoma presumably would be the result of other mechanisms. However, BMD in patients with a history of chondrosarcoma has not been well characterized. The aim of our study was to address the following questions: (1) Do long-term survivors of chondrosarcoma have normal BMD and, if not, which factors contribute to low BMD? (2) Is there a greater risk of fracture and does the Fracture Risk Assessment Tool (FRAX(®)) score reflect fracture likelihood? All known patients with a history of chondrosarcoma treated at our institution before 2006 were identified. Of 127 patients believed to be alive at the time of this study, 30 agreed to participate in this study (11 females, 19 males; mean age at surgery, 39 ± 12 years; mean followup, 12 ± 5 years). With the data available, the 30 participants were not different from the 97 nonparticipants in terms of age, sex, BMI, tumor grade, tumor location (axial versus appendicular, lower extremity versus elsewhere), and use of any treatment known to influence osteopenia (chemotherapy, lower extremity surgery). BMD was measured and history of fractures was assessed using a questionnaire. The patients´ BMD measurements in this study were sex- and age-matched with a normative sex- and age-categorized reference population reported by Kudlacek et al. Associations were tested by univariate regressions and ANOVAs of all measures of BMD and eligible oncologic and demographic factors. Eighteen of 30 (60%) patients had a pathologic BMD according to the WHO dual-energy x-ray absorptiometry definition, 15 (50%) had osteopenia, and three (10%) had osteoporosis. T-scores in the

  6. Effects of age and stand density of mother trees on early Pinus thunbergii seedling establishment in the coastal zone, China.

    Science.gov (United States)

    Mao, Peili; Han, Guangxuan; Wang, Guangmei; Yu, Junbao; Shao, Hongbo

    2014-01-01

    Effects of age and stand density of mother tree on seed germination, seedling biomass allocation, and seedling growth of Pinus thunbergii were studied. The results showed that age of mother tree did not have significant influences on seed germination, but it was significant on seedling biomass allocation and growth. Seedlings from the minimum and maximum age of mother tree had higher leaf mass ratio and lower root mass ratio than from the middle age of mother tree. Moreover, they also had higher relative height growth rate and slenderness, which were related to their biomass allocation. Stand density of mother tree mainly demonstrated significant effects on seed germination and seedling growth. Seed from higher stand density of mother tree did not decrease germination rate, but had higher mean germination time, indicating that it delayed germination process. Seedlings of higher stand density of mother tree showed higher relative height growth rate and slenderness. These traits of offspring from higher stand density of mother tree were similar to its mother, indicating significant environmental maternal effects. So, mother tree identity of maternal age and environments had important effects on natural regeneration of the coastal P. thunbergii forest.

  7. Osteoporotic-like effects of cadmium on bone mineral density and content in aged ovariectomized beagles

    International Nuclear Information System (INIS)

    Sacco-Gibson, N.; Abrams, J.; Chaudhry, S.; Hurst, D.; Peterson, D.; Bhattacharyya, M.

    1992-01-01

    Our purpose was to evaluate the effects of ovariectomy in conjunction with cadmium (Cd) exposure on bone. Aged female beagles with 45 Ca-labeled skeletons ovariectomized and exposed to Cd. Successive vertebral scans by dual photon absorptiometry monitored changes in bone mineral density (BMD) in each dog with time. Results showed that ovariectomy or Cd exposure alone caused significant decreases in BMD; ovariectomy with Cd exposure caused the greatest decrease. Ovariectomy alone did not decrease BMD in the distal end or mid-shaft of the tibia while BMD of the distal tibia decreased significantly due to Cd exposure alone. Combination treatment resulted in significant decreases in BMD of both tibial regions. At necropsy, tibiae, humeri, lumbar vertebrae and ribs were obtained for biochemical analysis. No group-to-group differences in bone weights (wet, dry, ash), in ash/dry ratios, or in long bone and vertebral Ca/dry or Ca/ash ratios were observed. Significantly higher total 45 Ca content and 45 Ca/dry and 45 Ca/ash ratios were observed in long bones and vertebrae of OV- and OV+ groups. In contrast, intact ribs showed significantly decreased Ca/dry and Ca/ash ratios compared to the SO-group. Quartered ribs demonstrated regional responses to specific treatment; decreases in total Ca content were greatest in the mid-rib region (-36 to -46%). Results suggest that in the aged female beagle, bone mineral loss associated with estrogen depletion is not only related to bone type (trabecular versus cortical) but also to bone Ca pools. Our results also suggest that a regional heterogeneity of bone plays a role in responsiveness to ovariectomy and Cd exposure. These aspects suggest that Cd is an exogenous factor affecting bone mineral loss independently of estrogen depletion. However, estrogen depletion primes bone for responsiveness to Cd-induced bone mineral loss

  8. Osteoporotic-like effects of cadmium on bone mineral density and content in aged ovariectomized beagles

    Energy Technology Data Exchange (ETDEWEB)

    Sacco-Gibson, N.; Abrams, J.; Chaudhry, S.; Hurst, D.; Peterson, D.; Bhattacharyya, M.

    1992-12-31

    Our purpose was to evaluate the effects of ovariectomy in conjunction with cadmium (Cd) exposure on bone. Aged female beagles with {sup 45}Ca-labeled skeletons ovariectomized and exposed to Cd. Successive vertebral scans by dual photon absorptiometry monitored changes in bone mineral density (BMD) in each dog with time. Results showed that ovariectomy or Cd exposure alone caused significant decreases in BMD; ovariectomy with Cd exposure caused the greatest decrease. Ovariectomy alone did not decrease BMD in the distal end or mid-shaft of the tibia while BMD of the distal tibia decreased significantly due to Cd exposure alone. Combination treatment resulted in significant decreases in BMD of both tibial regions. At necropsy, tibiae, humeri, lumbar vertebrae and ribs were obtained for biochemical analysis. No group-to-group differences in bone weights (wet, dry, ash), in ash/dry ratios, or in long bone and vertebral Ca/dry or Ca/ash ratios were observed. Significantly higher total {sup 45}Ca content and {sup 45}Ca/dry and {sup 45}Ca/ash ratios were observed in long bones and vertebrae of OV- and OV+ groups. In contrast, intact ribs showed significantly decreased Ca/dry and Ca/ash ratios compared to the SO-group. Quartered ribs demonstrated regional responses to specific treatment; decreases in total Ca content were greatest in the mid-rib region ({minus}36 to {minus}46%). Results suggest that in the aged female beagle, bone mineral loss associated with estrogen depletion is not only related to bone type (trabecular versus cortical) but also to bone Ca pools. Our results also suggest that a regional heterogeneity of bone plays a role in responsiveness to ovariectomy and Cd exposure. These aspects suggest that Cd is an exogenous factor affecting bone mineral loss independently of estrogen depletion. However, estrogen depletion primes bone for responsiveness to Cd-induced bone mineral loss.

  9. Urine cytokine and chemokine levels predict urinary tract infection severity independent of uropathogen, urine bacterial burden, host genetics, and host age.

    Science.gov (United States)

    Armbruster, Chelsie E; Smith, Sara N; Mody, Lona; Mobley, Harry L T

    2018-06-11

    Urinary tract infections (UTIs) are among the most common infections worldwide. Diagnosing UTIs in older adults poses a significant challenge as asymptomatic colonization is common. Identification of a non-invasive profile that predicts likelihood of progressing from urine colonization to severe disease would provide a significant advantage in clinical practice. We monitored colonization susceptibility, disease severity, and immune response to two uropathogens in two mouse strains across three age groups to identify predictors of infection outcome. Proteus mirabilis caused more severe disease than Escherichia coli, regardless of mouse strain or age, and was associated with differences in IL-1β, IFN-β, CXCL5 (LIX), CCL5 (RANTES), and CCL2 (MCP-1). In comparing the response to infection across age groups, mature adult mice were better able to control colonization and prevent progression to kidney colonization and bacteremia than young or aged mice, regardless of mouse strain or bacterial species, and this was associated with differences in IL-23, CXCL1, and CCL5. A bimodal distribution was noted for urine colonization, which was strongly associated with bladder CFUs and the magnitude of the immune response but independent of age or disease severity. To determine the value of urine cytokine and chemokine levels for predicting severe disease, all infection datasets were combined and subjected to a series of logistic regressions. A multivariate model incorporating IL-1β, CXCL1, and CCL2 had strong predictive value for identifying mice that did not develop kidney colonization or bacteremia, regardless of mouse genetic background, age, infecting bacterial species, or urine bacterial burden. In conclusion, urine cytokine profiles could potentially serve as a non-invasive decision-support tool in clinical practice and contribute to antimicrobial stewardship. Copyright © 2018 American Society for Microbiology.

  10. Effects of Population Density and Host Availability on The Migration Process of Brown Planthopper Fed Using Susceptible and Resistant Rice Varieties

    Directory of Open Access Journals (Sweden)

    Imam Habibi

    2016-12-01

    Full Text Available Brown planthopper, Nilaparvata lugens Stal. (Hemiptera: Delphacidae, is an important pest of rice. This pest can cause hopperburn and field failure. This research aimed to determine the effects of population density and host availability on migration of N. lugens. The criteria used to justify the effects of host availability and population density on migration of N. lugens were based the hardness and tannin tests of the rice stems, fecundity of N. lugens, and the life cycle of N. lugens. The research was conducted under the temperature of 29.42°C with relative humidity of 61% and Light 12: Dark 12 times, using ten pairs of N. lugens brachypterous (F0 constant and then was added with five male adults on fifth days after the first infestation (F0 changed. The varieties used were IR64, as a resistant variety, and Ketan Lusi, as a susceptible variety. The results showed that the adding of the macropterous males did not affect the number of macropterous, because of that has been preplanned by the F0. Therefore, the percentage of existing macropterous was 51−52%.   INTISARI   Wereng Batang Cokelat (WBC merupakan salah satu hama tanaman padi yang sangat penting. Kerusakan parah dapat menyebabkan hopperburn dan puso (gagal panen. Tujuan penelitian ini adalah mengetahui pengaruh kepadatan populasi dan tanaman inang sebagai tempat migrasi WBC. Parameter yang dikaji untuk mengetahui pengaruh kepadatan populasi WBC dan tanaman inang tempat migrasi WBC berdasarkan tingkat kekerasan dan kandungan tanin batang tanaman padi, fekunditas WBC, dan siklus hidup WBC. Penelitian ini dilakukan pada temperatur 29.42˚C dengan kelembapan relatif 61% dan durasi siang hari 12 jam: durasi malam hari 12 jam. Metode yang dilakukan adalah dengan menggunakan 10 pasang imago WBC brakhiptera (F0 konstan, kemudian dilakukan penambahan 5 ekor imago jantan pada hari kelima setelah infestasi awal (F0 diubah. Varietas padi yang digunakan yaitu padi varietas IR64 sebagai varietas

  11. Dose-response model of murine typhus (Rickettsia typhi: time post inoculation and host age dependency analysis

    Directory of Open Access Journals (Sweden)

    Tamrakar Sushil B

    2012-03-01

    Full Text Available Abstract Background Rickettsia typhi (R. mooseri is the causative agent of murine typhus. It is one of the most widely distributed flea-borne diseases with a relatively mild febrile initial illness with six to 14 days of incubation period. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through fleabites or via contact with infected feces. This paper develops dose-response models of different routes of exposure for typhus in rodents. Methods Data from published articles were analyzed using parametric dose-response relationship models. Dose-response relationships were fit to data using the method of maximum likelihood estimation (MLE. Results Dose-response models quantifying the effects of different ages of rats and time post inoculation in BALB/c mice were analyzed in the study. Both the adult rats (inoculated intradermally and newborn rats (inoculated subcutaneously were best fit by exponential models and both distributions could be described by a single dose-response relationship. The BALB/C mice inoculated subcutaneously were best fit by Beta-Poisson models. The time post inoculation analysis showed that there was a definite time and response relationship existed in this case. Conclusions Intradermally or subcutaneously inoculated rats (adult and newborn models suggest that less than 1 plaque-forming unit (PFU (1.33 to 0.38 in 95% confidence limits of the pathogen is enough to seroconvert 50% of the exposed population on average. For the BALB/c mouse time post inoculation model, an average dose of 0.28 plaque-forming units (PFU (0.75 to 0.11 in 95% confidence limits will seroconvert 50% of the exposed mice.

  12. Whole-brain grey matter density predicts balance stability irrespective of age and protects older adults from falling.

    Science.gov (United States)

    Boisgontier, Matthieu P; Cheval, Boris; van Ruitenbeek, Peter; Levin, Oron; Renaud, Olivier; Chanal, Julien; Swinnen, Stephan P

    2016-03-01

    Functional and structural imaging studies have demonstrated the involvement of the brain in balance control. Nevertheless, how decisive grey matter density and white matter microstructural organisation are in predicting balance stability, and especially when linked to the effects of ageing, remains unclear. Standing balance was tested on a platform moving at different frequencies and amplitudes in 30 young and 30 older adults, with eyes open and with eyes closed. Centre of pressure variance was used as an indicator of balance instability. The mean density of grey matter and mean white matter microstructural organisation were measured using voxel-based morphometry and diffusion tensor imaging, respectively. Mixed-effects models were built to analyse the extent to which age, grey matter density, and white matter microstructural organisation predicted balance instability. Results showed that both grey matter density and age independently predicted balance instability. These predictions were reinforced when the level of difficulty of the conditions increased. Furthermore, grey matter predicted balance instability beyond age and at least as consistently as age across conditions. In other words, for balance stability, the level of whole-brain grey matter density is at least as decisive as being young or old. Finally, brain grey matter appeared to be protective against falls in older adults as age increased the probability of losing balance in older adults with low, but not moderate or high grey matter density. No such results were observed for white matter microstructural organisation, thereby reinforcing the specificity of our grey matter findings. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Post-stroke gaseous hypothermia increases vascular density but not neurogenesis in the ischemic penumbra of aged rats

    DEFF Research Database (Denmark)

    Sandu, Raluca Elena; Uzoni, Adriana; Ciobanu, Ovidiu

    2016-01-01

    of several genes involved in protein degradation, thereby leading to better preservation of infarcted tissue. Further, hypothermia increased the density of newly formed blood vessels in the peri-lesional cortex did not enhance neurogenesis in the infarcted area of aged rats. Likewise, there was improved......-PCR and immunofluorescence, we assessed infarct size, vascular density, neurogenesis and as well as the expression of genes coding for proteasomal proteins as well as in post-stroke aged Sprague-Dawley rats exposed to H2S- induced hypothermia. Results: Two days exposure to mild hypothermia diminishes the expression...

  14. The population density of Lymnaea columella (Say, 1817) (Mollusca, Lymnaeidae) an intermediate host of Fasciola hepatica (Linnaeus, 1758), in the Caparaó microregion, ES, Brazil.

    Science.gov (United States)

    D'Almeida, S C G; Freitas, D F; Carneiro, M B; Camargo, P F; Azevedo, J C; Martins, I V F

    2016-06-01

    The aim of this study was to monitor the population density of Lymnaea columella, an intermediate host of Fasciola hepatica, in various aquatic habitats and in drinking water in the area of the Instituto Federal de Educação, Ciência e Tecnologia do Espírito Santo, on Caparaó Microregion, municipality of Alegre, state of Espírito Santo, Brazil. Monthly samplings were performed at certain points between drainage areas and drinking water in cattle and goat production systems during the years 2010 to 2013. The mean temperature, precipitation and the frequency of samples of L. columella were analysed graphically according the monthly average during the study period. A total of 2,038 molluscs were collected, 1558 of which were L. columella, that predominated in all sampled points. The highest average of specimens observed for L. columella was in the years 2010 and 2013 (51.0), and occurred decreased in 2011 (19.8). The temperature and precipitation averaged is 23.7 °C and 141 mm/year, respectively. Rainfall peak occurred in March (2011, 2013) and November (2012), during these periods the population of L. columella growth. There was no significant difference in the relationship between the specimens observed with seasons (dry-wet), thus the population of L. columella remained stable and can be found throughout the year.

  15. High-Density Lipoprotein Function in Exudative Age-Related Macular Degeneration.

    Directory of Open Access Journals (Sweden)

    Laura Pertl

    Full Text Available High-density lipoproteins (HDL have long been implicated in the pathogenesis of age-related macular degeneration (AMD. However, conflicting results have been reported with regard to the associations of AMD with HDL-cholesterol levels. The present study is the first to assess HDL composition and metrics of HDL function in patients with exudative AMD and control patients.Blood samples were collected from 29 patients with exudative AMD and 26 age-matched control patients. Major HDL associated apolipoproteins were determined in apoB-depleted serum by immunoturbidimetry or ELISA, HDL-associated lipids were quantified enzymatically. To get an integrated measure of HDL quantity and quality, we assessed several metrics of HDL function, including cholesterol efflux capacity, anti-oxidative and anti-inflammatory activities using apoB-depleted serum from study participants.In our study, we observed that the HDL associated acute phase protein serum amyloid A (SAA was significantly increased in AMD patients (p<0.01, whereas all other assessed apolipoproteins including ApoA-I, apoA-II, apoC-II, apoC-III and apoE as well as major HDL associated lipids were not altered. HDL efflux capacity, anti-oxidative capacity and arylesterase activity were not different in AMD patients when compared with the control group. The ability of apoB-depleted serum to inhibit monocyte NF-κB expression was significantly improved in AMD patients (mean difference (MD -5.6, p<0.01. Moreover, lipoprotein-associated phospholipase A2 activity, a marker of vascular inflammation, was decreased in AMD subjects (MD -24.1, p<0.01.The investigated metrics of HDL composition and HDL function were not associated with exudative AMD in this study, despite an increased content of HDL associated SAA in AMD patients. Unexpectedly, anti-inflammatory activity of apoB-depleted serum was even increased in our study. Our data suggest that the investigated parameters of serum HDL function showed no

  16. The effects of planting density and cultural intensity on loblolly pine crown characteristics at age twelve

    Science.gov (United States)

    Madison Akers; Michael Kane; Robert Teskey; Richard Daniels; Dehai Zhao; Santosh Subedi

    2012-01-01

    Twelve-year old loblolly pine (Pinus taeda L.) stands were analyzed for the effects of planting density and cultural intensity on tree and crown attributes. Four study installations were located in the Piedmont and Upper Coastal Plain regions of the U.S. South. The treatments included six planting densities (740, 1480, 2220, 2960, 3700, 4440 trees...

  17. Association between mammographic density and pregnancies relative to age and BMI: a breast cancer case-only analysis.

    Science.gov (United States)

    Hack, Carolin C; Emons, Julius; Jud, Sebastian M; Heusinger, Katharina; Adler, Werner; Gass, Paul; Haeberle, Lothar; Heindl, Felix; Hein, Alexander; Schulz-Wendtland, Rüdiger; Uder, Michael; Hartmann, Arndt; Beckmann, Matthias W; Fasching, Peter A; Pöhls, Uwe G

    2017-12-01

    Percentage mammographic density (PMD) is a major risk factor for breast cancer (BC). It is strongly associated with body mass index (BMI) and age, which are themselves risk factors for breast cancer. This analysis investigated the association between the number of full-term pregnancies and PMD in different subgroups relative to age and BMI. Patients were identified in the breast cancer database of the University Breast Center for Franconia. A total of 2410 patients were identified, for whom information on parity, age, and BMI, and a mammogram from the time of first diagnosis were available for assessing PMD. Linear regression analyses were conducted to investigate the influence on PMD of the number of full-term pregnancies (FTPs), age, BMI, and interaction terms between them. As in previous studies, age, number of FTPs, and BMI were found to be associated with PMD in the expected direction. However, including the respective interaction terms improved the prediction of PMD even further. Specifically, the association between PMD and the number of FTPs differed in young patients under the age of 45 (mean decrease of 0.37 PMD units per pregnancy) from the association in older age groups (mean decrease between 2.29 and 2.39 PMD units). BMI did not alter the association between PMD and the number of FTPs. The effect of pregnancies on mammographic density does not appear to become apparent before the age of menopause. The mechanism that drives the effect of pregnancies on mammographic density appears to be counter-regulated by other influences on mammographic density in younger patients.

  18. High levels of prevalence related to age and body condition: host-parasite interactions in a water frog Pelophylax kl hispanicus

    Directory of Open Access Journals (Sweden)

    Mar Comas

    2014-06-01

    Full Text Available Host traits can significantly influence patterns of infection and disease. Here, we studied the helminths parasitizing the Italian edible frog Pelophylax kl. hispanicus, giving special attention to the relationship between parasites and host traits such as sex, snout vent length, weight and body condition. The helminth community was composed of seven species: three trematode species (Diplodiscus subclavatus, Gorgodera cygnoides, Pleurogenes claviger, three nematode species (Icosiella neglecta, Oswaldocruzia filiformis, Rhabdias sp. and one acanthocephalan species (Pomphorhychus laevis. We found that prevalence was positively correlated with snout-vent length and weight, but did not differ with body condition or sex. We found that prevalence and mean species richness increased with age. Our results show that abundance of Icosiella neglecta was positively correlated with higher values for host body condition. In fact, we found that high prevalence and mean species richness do not necessarily imply poorer body condition in the parasitized host. In conclusion, our results show that the helminth community in this taxon has great diversity, and this host-parasite system seems to be evolved to low levels of virulence, helminths maintaining a commensal relationship with this frog.

  19. Dietary acid load, trabecular bone integrity, and mineral density in an ageing population: the Rotterdam study.

    Science.gov (United States)

    de Jonge, E A L; Koromani, F; Hofman, A; Uitterlinden, A G; Franco, O H; Rivadeneira, F; Kiefte-de Jong, J C

    2017-08-01

    We studied the relation between a diet that is high in acid-forming nutrients (e.g. proteins) and low in base-forming nutrients (e.g. potassium) and bone structure. We showed a negative relation, which was more prominent if proteins were of animal rather than of vegetable origin and if intake of dietary fibre was high. Studies on dietary acid load (DAL) and fractures have shown inconsistent results. Associations between DAL, bone mineral density (BMD) and trabecular bone integrity might play a role in these inconsistencies and might be influenced by renal function and dietary fibre intake. Therefore, our aim was to study (1) associations of DAL with BMD and with the trabecular bone score (TBS) and (2) the potential influence of renal function and dietary fibre in these associations. Dutch individuals aged 45 years and over (n = 4672) participating in the prospective cohort of the Rotterdam study were included. Based on food frequency questionnaires, three indices of DAL were calculated: the net endogenous acid production (NEAP) and the ratios of vegetable or animal protein and potassium (VegPro/K and AnPro/K). Data on lumbar spinal TBS and BMD were derived from dual-energy X-ray absorptiometry measurements. Independent of confounders, NEAP and AnPro/K, but not VegPro/K, were associated with low TBS (standardized β (95%) = -0.04 (-0.07, -0.01) and -0.08 (-0.11, -0.04)) but not with BMD. Associations of AnPro/K and VegPro/K with TBS were non-linear and differently shaped. Unfavourable associations between NEAP, BMD and TBS were mainly present in subgroups with high fibre intake. High NEAP was associated with low TBS. Associations of AnPro/K and VegPro/K and TBS were non-linear and differently shaped. No significant associations of DAL with BMD were observed, nor was there any significant interaction between DAL and renal function. Mainly in participants with high intake of dietary fibre, DAL might be detrimental to bone.

  20. Age- and gender-related distribution of bone mineral density and mechanical properties of the proximal humerus

    International Nuclear Information System (INIS)

    Lill, H.; Hepp, P.; Korner, J.; Josten, C.; Gowin, W.; Oestmann, J.W.; Haas, N.P.; Duda, G.N.

    2002-01-01

    Purpose: To evaluate age- and gender-related mechanical properties and bone mineral density (BMD) of the proximal humerus at different levels and regions. Materials and methods: Mechanical indentation testing, DXA, QCT, pQCT and the radiogrammetry (Cortical Index, CI) were carried out in 70 freshly harvested humeri from 46 human cadavers (23 females, 23-males; median age 70.5 years). Results: In the female group, a high correlation between age and BMD was found (ρ=0.62 to -0.70, p [de

  1. Influence of host age on critical fitness parameters of Spathius galinae (Hymenoptera: Braconidae), a new parasitoid of the emerald ash borer (Coleoptera: Buprestidae).

    Science.gov (United States)

    Watt, Timothy J; Duan, Jian J

    2014-08-01

    Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae) is a recently discovered gregarious idiobiont larval ectoparasitoid currently being evaluated for biological control against the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in the United States. To aid in the development of laboratory rearing protocols, we assessed the influence of various emerald ash borer stages on critical fitness parameters of S. galinae. We exposed gravid S. galinae females to emerald ash borer host larvae of various ages (3.5, 5, 7, and 10 wk post egg oviposition) that were reared naturally in tropical (evergreen) ash (Fraxinus uhdei (Wenzig) Lingelsh) logs, or to field-collected, late-stage emerald ash borers (nonfeeding J-shaped larvae termed "J-larvae," prepupae, and pupae) that were artificially inserted into green ash logs. When exposed to larvae in tropical ash logs, S. galinae attacked 5 and 7 wk hosts more frequently (68-76%) than 3.5 wk (23%) and 10 wk (12%) hosts. Subsample dissections of the these logs revealed that 3.5, 5, 7 and 10 wk host logs contained mostly second, third, fourth, and J-larvae, respectively, that had already bored into the sapwood for diapause. No J-larvae were attacked by S. galinae when naturally reared in tropical ash logs. When parasitized by S. galinae, 7 and 10 wk hosts produced the largest broods (approximately 6.7 offspring per parasitized host), and the progenies that emerged from these logs had larger anatomical measurements and more female-biased sex ratios. When exposed to emerald ash borer J-larvae, prepupae, or pupae artificially inserted into green ash logs, S. galinae attacked 53% ofJ-larvae, but did not attack any prepupae or pupae. We conclude that large (fourth instar) emerald ash borer larvae should be used to rear S. galinae.

  2. Aging memory for pictures: Using high-density event-related potentials to understand the effect of aging on the picture superiority effect

    OpenAIRE

    Ally, Brandon A.; Waring, Jill D.; Beth, Ellen H.; McKeever, Joshua D.; Milberg, William P.; Budson, Andrew E.

    2007-01-01

    High-density event-related potentials (ERPs) were used to understand the effect of aging on the neural correlates of the picture superiority effect. Pictures and words were systematically varied at study and test while ERPs were recorded at retrieval. Here, the results of the word-word and picture-picture study-test conditions are presented. Behavioral results showed that older adults demonstrated the picture superiority effect to a greater extent than younger adults. The ERP data helped to e...

  3. Shifts in Host Mucosal Innate Immune Function Are Associated with Ruminal Microbial Succession in Supplemental Feeding and Grazing Goats at Different Ages

    Directory of Open Access Journals (Sweden)

    Jinzhen Jiao

    2017-08-01

    Full Text Available Gastrointestinal microbiota may play an important role in regulating host mucosal innate immune function. This study was conducted to test the hypothesis that age (non-rumination, transition and rumination and feeding type [Supplemental feeding (S vs. Grazing (G] could alter ruminal microbial diversity and maturation of host mucosal innate immune system in goat kids. MiSeq sequencing was applied to investigate ruminal microbial composition and diversity, and RT-PCR was used to test expression of immune-related genes in ruminal mucosa. Results showed that higher (P < 0.05 relative abundances of Prevotella, Butyrivibrio, Pseudobutyrivibrio, Methanobrevibacter.gottschalkii, Neocallimastix, Anoplodinium–Diplodinium, and Polyplastron, and lower relative abundance of Methanosphaera (P = 0.042 were detected in the rumen of S kids when compared to those in G kids. The expression of genes encoding TLRs, IL1α, IL1β and TICAM2 was down-regulated (P < 0.01, while expression of genes encoding tight junction proteins was up-regulated (P < 0.05 in the ruminal mucosa of S kids when compared to that in G kids. Moreover, irrespective of feeding type, relative abundances of ruminal Prevotella, Fibrobacter, Ruminococcus, Butyrivibrio, Methanobrevibacter, Neocallimastix, and Entodinium increased with age. The expression of most genes encoding TLRs and cytokines increased (P < 0.05 from day 0 to 7, while expression of genes encoding tight junction proteins declined with age (P < 0.05. This study revealed that the composition of each microbial domain changed as animals grew, and these changes might be associated with variations in host mucosal innate immune function. Moreover, supplementing goat kids with concentrate could modulate ruminal microbial composition, enhance barrier function and decrease local inflammation. The findings provide useful information in interpreting microbiota and host interactions, and developing nutritional strategies to improve the

  4. effect of age, female mating status and density on the banana weevil ...

    African Journals Online (AJOL)

    journal

    Laboratory bioassays were conducted using a double pitfall olfactometer, while a bucket pitfall trap was ... baited trap. The response of the weevils to the pheromone was not significantly (P>0.05) influenced by its previous density. Key Words: Cosmopolites sordidus, mating status, ...... evolutionary ecological perspective.

  5. Effects of density on foraging success and aggression in age-structured groups of brown trout

    DEFF Research Database (Denmark)

    Kaspersson, Rasmus; Höjesjö, Johan; Pedersen, Stig

    2010-01-01

    , as a consequence of, for example, age and/or body size. We used two age classes (i.e. size groups) of stream-living brown trout, Salmo trutta, to investigate this issue. While old (and large) trout are assumed to be superior during interference competition, younger individuals may be both numerically dominant...

  6. All-MXene-Based Integrated Electrode Constructed by Ti3C2 Nanoribbon Framework Host and Nanosheet Interlayer for High-Energy-Density Li-S Batteries.

    Science.gov (United States)

    Dong, Yanfeng; Zheng, Shuanghao; Qin, Jieqiong; Zhao, Xuejun; Shi, Haodong; Wang, Xiaohui; Chen, Jian; Wu, Zhong-Shuai

    2018-03-27

    High-energy-density lithium-sulfur (Li-S) batteries hold promise for next-generation portable electronic devices, but are facing great challenges in rational construction of high-performance flexible electrodes and innovative cell configurations for actual applications. Here we demonstrated an all-MXene-based flexible and integrated sulfur cathode, enabled by three-dimensional alkalized Ti 3 C 2 MXene nanoribbon (a-Ti 3 C 2 MNR) frameworks as a S/polysulfides host (a-Ti 3 C 2 -S) and two-dimensional delaminated Ti 3 C 2 MXene (d-Ti 3 C 2 ) nanosheets as interlayer on a polypropylene (PP) separator, for high-energy and long-cycle Li-S batteries. Notably, an a-Ti 3 C 2 MNR framework with open interconnected macropores and an exposed surface area guarantees high S loading and fast ionic diffusion for prompt lithiation/delithiation kinetics, and the 2D d-Ti 3 C 2 MXene interlayer remarkably prevents the shuttle effect of lithium polysulfides via both chemical absorption and physical blocking. As a result, the integrated a-Ti 3 C 2 -S/d-Ti 3 C 2 /PP electrode was directly used for Li-S batteries, without the requirement of a metal current collector, and exhibited a high reversible capacity of 1062 mAh g -1 at 0.2 C and enhanced capacity of 632 mAh g -1 after 50 cycles at 0.5 C, outperforming the a-Ti 3 C 2 -S/PP electrode (547 mAh g -1 ) and conventional a-Ti 3 C 2 -S on an Al current collector (a-Ti 3 C 2 -S/Al) (597 mAh g -1 ). Furthermore, the all-MXene-based integrated cathode displayed outstanding rate capacity of 288 mAh g -1 at 10 C and long-life cyclability. Therefore, this proposed strategy of constructing an all-MXene-based cathode can be readily extended to assemble a large number of MXene-derived materials, from a group of 60+ MAX phases, for applications such as various batteries and supercapacitors.

  7. Population density of oil palm pollinator weevil Elaeidobius kamerunicus based on seasonal effect and age of oil palm

    Science.gov (United States)

    Daud, Syarifah Nadiah Syed Mat; Ghani, Idris Abd.

    2016-11-01

    The pollinating weevil, Elaedobius kamerunicus (EK) has been known to be the most efficient insect pollinator of oil palm, and has successfully improved the oil palm pollination and increased the yield. Its introduction has greatly reduced the need for assisted pollination. The purpose of this study was to identify the population density of oil palm pollinator weevil EK using the concept of pollinator force and to relate the population density with the seasonal effect and the age of oil palm at Lekir Oil Palm Plantation Batu 14, Perak, Peninsular Malaysia. The pollinator force of the weevil was sustained at a range between 3095.2 to 19126.1 weevils per ha. The overall mean of weevil per spikelet shows that the range of weevil was between 13.51 and 54.06 per spikelet. There was no correlation between rainfall and population density of EK. However, positive correlation was obtained between weevil density and the number of anthesising female inflorescence of oil palm (r= 0.938, poil palm stands had significantly different population density than that of a 8-year old oil palm stand. The information of this study should be useful as a baseline data to investigate why there is such a wide range of weevils per ha or spikelet. Further study should also be done to relate the number pollinator force per spikelete and the Fresh fruit Bunch (FFB), fruit set or fruit to bunch ratio.

  8. Modelling Age- and Density-Related Gas Exchange of Picea abies Canopies in the Fichtelgebirge, Germany

    OpenAIRE

    Falge, Eva; Tennhunen, John D.; Ryel, Ronald J.; Alsheimer, Martina; Köstner, Barbara

    2000-01-01

    International audience; Differences in canopy exchange of water and carbon dioxide that occur due to changes in tree structure and density in montane Norway spruce stands of Central Germany were analyzed with a three dimensional microclimate and gas exchange model STANDFLUX. The model was used to calculate forest radiation absorption, the net photosynthesis and transpiration of single trees, and gas exchange of tree canopies. Model parameterizations were derived for six stands of Picea abies ...

  9. Mammographic density and ageing: A collaborative pooled analysis of cross-sectional data from 22 countries worldwide.

    Directory of Open Access Journals (Sweden)

    Anya Burton

    2017-06-01

    Full Text Available Mammographic density (MD is one of the strongest breast cancer risk factors. Its age-related characteristics have been studied in women in western countries, but whether these associations apply to women worldwide is not known.We examined cross-sectional differences in MD by age and menopausal status in over 11,000 breast-cancer-free women aged 35-85 years, from 40 ethnicity- and location-specific population groups across 22 countries in the International Consortium on Mammographic Density (ICMD. MD was read centrally using a quantitative method (Cumulus and its square-root metrics were analysed using meta-analysis of group-level estimates and linear regression models of pooled data, adjusted for body mass index, reproductive factors, mammogram view, image type, and reader. In all, 4,534 women were premenopausal, and 6,481 postmenopausal, at the time of mammography. A large age-adjusted difference in percent MD (PD between post- and premenopausal women was apparent (-0.46 cm [95% CI: -0.53, -0.39] and appeared greater in women with lower breast cancer risk profiles; variation across population groups due to heterogeneity (I2 was 16.5%. Among premenopausal women, the √PD difference per 10-year increase in age was -0.24 cm (95% CI: -0.34, -0.14; I2 = 30%, reflecting a compositional change (lower dense area and higher non-dense area, with no difference in breast area. In postmenopausal women, the corresponding difference in √PD (-0.38 cm [95% CI: -0.44, -0.33]; I2 = 30% was additionally driven by increasing breast area. The study is limited by different mammography systems and its cross-sectional rather than longitudinal nature.Declines in MD with increasing age are present premenopausally, continue postmenopausally, and are most pronounced over the menopausal transition. These effects were highly consistent across diverse groups of women worldwide, suggesting that they result from an intrinsic biological, likely hormonal, mechanism common to

  10. Metal accumulation in roadside soil in Melbourne, Australia: Effect of road age, traffic density and vehicular speed

    International Nuclear Information System (INIS)

    De Silva, Shamali; Ball, Andrew S.; Huynh, Trang; Reichman, Suzie M.

    2016-01-01

    Concentrations of vehicular emitted heavy metals in roadside soils result in long term environmental damage. This study assessed the relationships between traffic characteristics (traffic density, road age and vehicular speed) and roadside soil heavy metals. Significant levels were recorded for Cd (0.06–0.59 mg/kg), Cr (18–29 mg/kg), Cu (4–12 mg/kg), Ni (7–20 mg/kg), Mn (92–599 mg/kg), Pb (16–144 mg/kg) and Zn (10.36–88.75 mg/kg), with Mn concentrations exceeding the Ecological Investigation Level. Significant correlations were found between roadside soil metal concentration and vehicular speed (R = 0.90), road age (R = 0.82) and traffic density (R = 0.68). Recently introduced metals in automotive technology (e.g. Mn and Sb) were higher in younger roads, while the metals present for many years (e.g. Cd, Cu, Pb, Zn) were higher in medium and old age roads confirming the risk of significant metal deposition and soil metal retention in roadside soils. - Highlights: • Elevated metal concentrations were recorded from Melbourne roadside soils. • Mn and Sb tended to be higher in younger roads. • Cd, Cu, Pb and Zn were particularly elevated in medium and old age roads. • Accumulation of Ag, Co and Sb were identified as potential emerging risks. • Mn concentrations exceeded Australian ecological investigation levels. - Investigating relationships between road age, traffic density and vehicular speed on the concentrations of metals in roadside soils.

  11. Effect of reproductive history, lactation, first pregnancy age and dietary habits on bone mineral density in natural postmenopausal women.

    Science.gov (United States)

    Cavkaytar, Sabri; Seval, Mehmet Murat; Atak, Zeliha; Findik, Rahime Bedir; Ture, Sevgi; Kokanali, Demet

    2015-10-01

    The aim of this study was to investigate the possible risk factors related with osteoporosis in women with spontaneous menopause. Five hundred and one postmenopausal women were divided into three groups as normal, osteopenic and osteoporotic according to their bone mineral density (BMD). By face-to-face interview, parity, age at menarche, age at menopause, duration of fertility, duration of menopause, first pregnancy age, total lactation period, exercise, smoking were assessed. Women with menopause age before 40 years, surgical menopause, who had any anti-osteoporosis treatment, hormone replacement therapy at the time of BMD measurement and corticosteroid use longer than 6 months were excluded from the study. Among 501 postmenopausal women, 107 women were classified as normal, 170 as osteopenic and 224 as osteoporotic. Among demographic features of patients, there was statistically significant difference between the groups in age, BMI and parity (p osteoporosis (OR 0.42, CI 95 % 0.27-0.66; OR 0.36, CI 95 % 0.24-0.56, respectively), but age was positively correlated with osteoporosis (OR 1.13, CI 95 % 1.01-1.17) CONCLUSIONS: Duration of fertility (years of menstruation) longer than 33 years and body mass index higher than 32 seem to protect against postmenopausal osteoporosis. Age is also an independent risk factor for postmenopausal osteoporosis.

  12. Age-predicted values for lumbar spine, proximal femur, and whole-body bone mineral density: results from a population of normal children aged 3 to 18 years

    Energy Technology Data Exchange (ETDEWEB)

    Webber, C.E. [Hamilton Health Sciences, Dept. of Nuclear Medicine, Hamilton, Ontario (Canada); McMaster Univ., Dept. of Radiology, Hamilton, Ontario (Canada)]. E-mail: webber@hhsc.ca; Beaumont, L.F. [Hamilton Health Sciences, Dept. of Nuclear Medicine, Hamilton, Ontario (Canada); Morrison, J. [McMaster Children' s Hospital, Hamilton, Ontario (Canada); Sala, A. [McMaster Children' s Hospital, Hamilton, Ontario (Canada); McMaster Univ., Dept. of Pediatrics, Hamilton, Ontario (Canada); Univ. of Milan-Bicocca, Monza (Italy); Barr, R.D. [McMaster Children' s Hospital, Hamilton, Ontario (Canada); McMaster Univ., Dept. of Pediatrics, Hamilton, Ontario (Canada)

    2007-02-15

    We measured areal bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA) at the lumbar spine and the proximal femur and for the total body in 179 subjects (91 girls and 88 boys) with no known disorders that might affect calcium metabolism. Results are also reported for lumbar spine bone mineral content (BMC) and for the derived variable, bone mineral apparent density (BMAD). Expected-for-age values for each variable were derived for boys and girls by using an expression that represented the sum of a steady increase due to growth plus a rapid increase associated with puberty. Normal ranges were derived by assuming that at least 95% of children would be included within 1.96 population standard deviations (SD) of the expected-for-age value. The normal range for lumbar spine BMD derived from our population of children was compared with previously published normal ranges based on results obtained from different bone densitometers in diverse geographic locations. The extent of agreement between the various normal ranges indicates that the derived expressions can be used for reporting routine spine, femur, and whole-body BMD measurements in children and adolescents. The greatest difference in expected-for-age values among the various studies was that arising from intermanufacturer variability. The application of published conversion factors derived from DXA measurements in adults did not account fully for these differences, especially in younger children. (author)

  13. Age-predicted values for lumbar spine, proximal femur, and whole-body bone mineral density: results from a population of normal children aged 3 to 18 years

    International Nuclear Information System (INIS)

    Webber, C.E.; Beaumont, L.F.; Morrison, J.; Sala, A.; Barr, R.D.

    2007-01-01

    We measured areal bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA) at the lumbar spine and the proximal femur and for the total body in 179 subjects (91 girls and 88 boys) with no known disorders that might affect calcium metabolism. Results are also reported for lumbar spine bone mineral content (BMC) and for the derived variable, bone mineral apparent density (BMAD). Expected-for-age values for each variable were derived for boys and girls by using an expression that represented the sum of a steady increase due to growth plus a rapid increase associated with puberty. Normal ranges were derived by assuming that at least 95% of children would be included within 1.96 population standard deviations (SD) of the expected-for-age value. The normal range for lumbar spine BMD derived from our population of children was compared with previously published normal ranges based on results obtained from different bone densitometers in diverse geographic locations. The extent of agreement between the various normal ranges indicates that the derived expressions can be used for reporting routine spine, femur, and whole-body BMD measurements in children and adolescents. The greatest difference in expected-for-age values among the various studies was that arising from intermanufacturer variability. The application of published conversion factors derived from DXA measurements in adults did not account fully for these differences, especially in younger children. (author)

  14. Absolute and estimated values of macular pigment optical density in young and aged Asian participants with or without age-related macular degeneration.

    Science.gov (United States)

    Ozawa, Yoko; Shigeno, Yuta; Nagai, Norihiro; Suzuki, Misa; Kurihara, Toshihide; Minami, Sakiko; Hirano, Eri; Shinoda, Hajime; Kobayashi, Saori; Tsubota, Kazuo

    2017-08-29

    Lutein and zeaxanthin are suggested micronutrient supplements to prevent the progression of age-related macular degeneration (AMD), a leading cause of blindness worldwide. To monitor the levels of lutein/zeaxanthin in the macula, macular pigment optical density (MPOD) is measured. A commercially available device (MPSII®, Elektron Technology, Switzerland), using technology based on heterochromatic flicker photometry, can measure both absolute and estimated values of MPOD. However, whether the estimated value is applicable to Asian individuals and/or AMD patients remains to be determined. The absolute and estimated values of MPOD were measured using the MPSII® device in 77 participants with a best-corrected visual acuity (BCVA) > 0.099 (logMAR score). The studied eyes included 17 young (20-29 years) healthy, 26 aged (>50 years) healthy, 18 aged and AMD-fellow, and 16 aged AMD eyes. The mean BCVA among the groups were not significantly different. Both absolute and estimated values were measurable in all eyes of young healthy group. However, absolute values were measurable in only 57.7%, 66.7%, and 43.8%, of the aged healthy, AMD-fellow, and AMD groups, respectively, and 56.7% of the eyes included in the 3 aged groups. In contrast, the estimated value was measurable in 84.6%, 88.9% and 93.8% of the groups, respectively, and 88.3% of eyes in the pooled aged group. The estimated value was correlated with absolute value in individuals from all groups by Spearman's correlation coefficient analyses (young healthy: R 2  = 0.885, P = 0.0001; aged healthy: R 2  = 0.765, P = 0.001; AMD-fellow: R 2  = 0.851, P = 0.0001; and AMD: R 2  = 0.860, P = 0.013). Using the estimated value, significantly lower MPOD values were found in aged AMD-related eyes, which included both AMD-fellow and AMD eyes, compared with aged healthy eyes by Student's t-test (P = 0.02). Absolute, in contrast to estimated, value was measurable in a limited number of aged participants

  15. DNA repair in human fibroblasts, as reflected by host-cell reactivation of a transfected UV-irradiated luciferase gene, is not related to donor age

    International Nuclear Information System (INIS)

    Merkle, Thomas J.; O'Brien, Katherine; Brooks, Philip J.; Tarone, Robert E.; Robbins, Jay H.

    2004-01-01

    The effect of donor age on the ability of mammalian cells to repair ultraviolet (UV)-induced DNA damage has been studied using several approaches, most recently via assays that measure the host-cell reactivation (HCR) of UV-irradiated reporter gene-containing plasmid vectors following their transfection into cells. Plasmid HCR assays indirectly quantify a cell line's ability to perform nucleotide excision repair (NER) by measuring the enzyme activity of the repaired reporter gene, e.g., chloramphenical acetyltransferase (cat) or luciferase (luc), and are useful in studies investigating whether increasing age may be a risk factor for the deficient repair of potentially cancer-causing, sunlight-induced, DNA lesions in skin cells. In our study, we quantified the DNA repair ability of cultured, nontransformed, human skin fibroblast lines through their HCR of a transfected UV-C-irradiated plasmid containing luc. HCR was measured at various times after transfection in five lines from normal donors of ages 21-96 years, and from one donor who had xeroderma pigmentosum (XP). The normal lines displayed increasing HCR at successive post-transfection time points and showed no significant correlation between HCR and donor age. The XP-A line, known to be markedly deficient in NER of UV-induced DNA damage, showed minimal evidence of HCR compared to the normal lines. To further assess potential variation in HCR with donor age, fibroblast lines from five old donors, ages 84-94 years, were compared with lines from five young donors, ages 17-26 years. While significant differences in HCR were found between some lines, no significant difference was found between the young and old age groups (P=0.44). Our study provides no indication that the higher incidence of skin cancer observed with increasing age is due to an age-related decrease in the ability to repair UV-induced DNA damage

  16. DNA repair in human fibroblasts, as reflected by host-cell reactivation of a transfected UV-irradiated luciferase gene, is not related to donor age

    Energy Technology Data Exchange (ETDEWEB)

    Merkle, Thomas J.; O' Brien, Katherine; Brooks, Philip J.; Tarone, Robert E.; Robbins, Jay H

    2004-10-04

    The effect of donor age on the ability of mammalian cells to repair ultraviolet (UV)-induced DNA damage has been studied using several approaches, most recently via assays that measure the host-cell reactivation (HCR) of UV-irradiated reporter gene-containing plasmid vectors following their transfection into cells. Plasmid HCR assays indirectly quantify a cell line's ability to perform nucleotide excision repair (NER) by measuring the enzyme activity of the repaired reporter gene, e.g., chloramphenical acetyltransferase (cat) or luciferase (luc), and are useful in studies investigating whether increasing age may be a risk factor for the deficient repair of potentially cancer-causing, sunlight-induced, DNA lesions in skin cells. In our study, we quantified the DNA repair ability of cultured, nontransformed, human skin fibroblast lines through their HCR of a transfected UV-C-irradiated plasmid containing luc. HCR was measured at various times after transfection in five lines from normal donors of ages 21-96 years, and from one donor who had xeroderma pigmentosum (XP). The normal lines displayed increasing HCR at successive post-transfection time points and showed no significant correlation between HCR and donor age. The XP-A line, known to be markedly deficient in NER of UV-induced DNA damage, showed minimal evidence of HCR compared to the normal lines. To further assess potential variation in HCR with donor age, fibroblast lines from five old donors, ages 84-94 years, were compared with lines from five young donors, ages 17-26 years. While significant differences in HCR were found between some lines, no significant difference was found between the young and old age groups (P=0.44). Our study provides no indication that the higher incidence of skin cancer observed with increasing age is due to an age-related decrease in the ability to repair UV-induced DNA damage.

  17. The National Ignition Facility: Ushering in a new age for high energy density science

    International Nuclear Information System (INIS)

    Moses, E. I.; Boyd, R. N.; Remington, B. A.; Keane, C. J.; Al-Ayat, R.

    2009-01-01

    The National Ignition Facility (NIF) [E. I. Moses, J. Phys.: Conf. Ser. 112, 012003 (2008); https://lasers.llnl.gov/], completed in March 2009, is the highest energy laser ever constructed. The high temperatures and densities achievable at NIF will enable a number of experiments in inertial confinement fusion and stockpile stewardship, as well as access to new regimes in a variety of experiments relevant to x-ray astronomy, laser-plasma interactions, hydrodynamic instabilities, nuclear astrophysics, and planetary science. The experiments will impact research on black holes and other accreting objects, the understanding of stellar evolution and explosions, nuclear reactions in dense plasmas relevant to stellar nucleosynthesis, properties of warm dense matter in planetary interiors, molecular cloud dynamics and star formation, and fusion energy generation.

  18. Effects of turbidity and prey density on the foraging success of age 0 year yellow perch Perca flavescens.

    Science.gov (United States)

    Wellington, C G; Mayer, C M; Bossenbroek, J M; Stroh, N A

    2010-05-01

    Laboratory experiments were conducted to determine how larval and juvenile yellow perch Perca flavescens respond to changes in prey density when exposed to different levels and types of turbidity (phytoplanktonic or sedimentary). Across prey densities, consumption by P. flavescens tended to be less in phytoplanktonic turbidity compared with sedimentary turbidity. For larvae, this effect was dependent on turbidity level (consumption differed between turbidity types only at high turbidity), while for juveniles the difference with turbidity type was equal across turbidity levels. These results suggest that phytoplankton blooms are detrimental to the ability of late season age 0 year P. flavescens to forage and support the need to control factors leading to excessive phytoplankton growth in lakes.

  19. Backwaters in the upper reaches of reservoirs produce high densities of age-0 crappies

    Science.gov (United States)

    Dagel, Jonah D.; Miranda, Leandro E.

    2012-01-01

    Reservoir backwaters are aquatic habitats in floodplains of reservoir tributaries that are permanently or periodically flooded by the reservoir. Like many reservoir arms, backwaters are commonly shallow, littoral habitats, but they differ from arms in various respects, including their support of primarily wetland plant assemblages that are tolerant to flooding. Elsewhere, the reservoir floods mainly upland plants that are less tolerant to flooding, producing a band of barren shoreline along the fluctuation zone. We investigated differences in relative abundance of age-0 crappies Pomoxis spp. in backwaters and arms of widely fluctuating flood control reservoirs, examined the effect of water level, and estimated the likelihood and timing with which these habitats are flooded annually. Higher catch rates of age-0 crappies were obtained in backwater habitats than in arm habitats. When inundated during the crappie spawning season, backwaters provided vegetated habitat at lower water levels than arms. Backwaters flooded earlier than arms and remained flooded longer to provide prolonged nursery habitat. Whereas vegetated habitat was inundated almost yearly in backwaters and arms, inundation that was timed to the onset of spawning occurred less regularly. Because of differences in water elevation, vegetated habitats were flooded in time for crappie spawning about every other year in backwaters but only every third year in arms. Recruitment of age-0 crappies was inversely correlated with high water levels during the months preceding the spawning period, perhaps because early flooding degraded the vegetation. Our results suggest that water levels may be managed during late winter and spring to regularly flood wetland vegetation communities in backwaters; however, water levels should be maintained at or below normal pool and should only irregularly flood upland vegetation in reservoir arms to promote the preservation of such vegetation. Furthermore, management efforts to

  20. Bone mineral density levels of college-aged women in northwest Arkansas.

    Science.gov (United States)

    Tokar, Kate; Ford, Mary Allison; Turner, Lori Waite; Denny, George

    2003-11-01

    Osteoporosis has affected more than 20 million American, women, completely altering their way of life. Osteoporosis is highly preventable if steps are taken to build healthy bone; however, many college students do not have lifestyle habits that have a positive effect on their bones. For this study, a questionnaire was used to investigate childhood dairy consumption, high school sport participation, dieting behaviors, eating behaviors and bone mineral density levels of college women at the University of Arkansas in Fayetteville. Eighty percent of the participants were Caucasian or of Asian descent, while 20% were of other races; 34% of the participants consumed three or more servings of milk a day as children, while current calcium consumption was at an average of 16 servings a week. Many of the participants were active in high school, as 67% participated in high school sports. Fifty-two percent of the college women in the sample had dieted in the past year, and 44% perceived they were not at a desirable weight. Forty-five percent skip more than three meals a week. Of the participants, two had osteoporosis and 23 had osteopenia. Clearly, development of osteoporosis is not limited to older adults, and college women are in need of education related to bone health.

  1. The effects of body posture, anatomy, age and pregnancy on the calculation of induced current densities at 50 Hz

    International Nuclear Information System (INIS)

    Dimbylow, P.; Findlay, R.

    2010-01-01

    This paper presents calculations of the induced current density in the body at 50 Hz from applied electric and magnetic fields. An extensive ensemble of 25 voxel models has been used to investigate the effects of body posture, anatomy, age and pregnancy. This set includes six adult models, eight child models and seven pregnant female models at various stages of gestation. The four postures investigated in the HPA adult model, NORMAN, were the standard position with the arms at the side, with the arms vertically above the head, the arms horizontally to the side and sitting. (authors)

  2. Vertebral fracture prevalence among Greek healthy middle-aged postmenopausal women: association with demographics, anthropometric parameters, and bone mineral density.

    Science.gov (United States)

    Lambrinoudaki, Irene; Flokatoula, Maria; Armeni, Eleni; Pliatsika, Paraskevi; Augoulea, Areti; Antoniou, Aris; Alexandrou, Andreas; Creatsa, Maria; Panoulis, Constantinos; Dendrinos, Spyridon; Papacharalambous, Xenofon

    2015-01-01

    The prevalence of skeletal fractures shows a marked geographic variability; however, data regarding the Greek population remain limited. To evaluate the frequency of asymptomatic vertebral fractures (VFs), and potential risk factors, in a large sample of Greek postmenopausal women. A cross-sectional study at the University Menopause Clinic. Four hundred fifty-four postmenopausal women aged 35 to 80 years, with an average menopausal age of 9.2±7.1 years. They included medical history, anthropometric and biochemical parameters, bone mineral density (BMD) at lumbar spine (LS) and femoral neck (FN), and LS lateral radiographs. Lumbar spine lateral radiographs were evaluated according to quantitative procedures, aiming to identify VFs. Anthropometric and biochemical parameters and values of BMD were compared according to the presence of VFs. A total of 37 (8.15%) women had at least one VF. Lumbar spine and FN-osteoporosis was identified in up to 23.1% and 40.9% subjects with prevalent VFs, respectively. The prevalence of VFs was largely associated with age, with women aged 60 years or more presenting an up to fourfold risk compared with younger women. Moreover, the presence of VFs was associated with higher menopausal age, advanced age at menarche, a history of early menopause, and prolonged lactation. Lower LS-BMD and, especially, FN-BMD were negatively associated with VF prevalence (prevalent VF vs. no VF: LS-BMD, 0.89±0.16 g/cm(2) vs. 0.98±0.16 g/cm(2), p=.010; FN-BMD, 0.72±0.10 g/cm(2) vs. 0.81±0.12 g/cm(2), p=.008). Asymptomatic VFs are common among Greek healthy middle-aged postmenopausal women. More than 50% subjects with prevalent VFs present with normal BMD or osteopenia. Age and bone density classification at the FN presented the strongest association with the prevalence of VFs. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Bone mineral density difference between right and left hip during ageing

    DEFF Research Database (Denmark)

    Schwarz, P.; Jørgensen, Niklas Rye; Jensen, L.T.

    2011-01-01

    be affected by significant left-right difference in hip BMD, especially in the old. The purpose of our study was to ascertain the difference in BMD measurement of the two hips in a population of Caucasian community dwelling women older than 65 years invited for screening. We found that bilateral BMD...... found an increasing difference between the hips with increasing age and this difference was up to 9.1% in the women older than 70 years when evaluating femoral neck, meaning that the diagnosis of osteoporosis in a subset of patients would depend on whether the left or right hip was scanned. When...... measurements were only moderately correlated at the femoral neck and total hip. In a significant number of the screened elderly women, we found that the DXA differences changed the diagnosis of each woman from either normal BMD to osteopenia or visa versa or from osteopenia to osteoporosis or visa versa. We...

  4. Bone Mineral Density difference between Right and Left Hip during Ageing

    DEFF Research Database (Denmark)

    Schwarz, P; Jørgensen, NR; Jensen, LT

    2011-01-01

    be affected by significant left-right difference in hip BMD, especially in the old. The purpose of our study was to ascertain the difference in BMD measurement of the two hips in a population of Caucasian community dwelling women older than 65 years invited for screening. We found that bilateral BMD...... found an increasing difference between the hips with increasing age and this difference was up to 9.1% in the women older than 70 years when evaluating femoral neck, meaning that the diagnosis of osteoporosis in a subset of patients would depend on whether the left or right hip was scanned. When...... measurements were only moderately correlated at the femoral neck and total hip. In a significant number of the screened elderly women, we found that the DXA differences changed the diagnosis of each woman from either normal BMD to osteopenia or visa versa or from osteopenia to osteoporosis or visa versa. We...

  5. Amount of smoking, pulmonary function, and bone mineral density in middle-aged Korean men: KNHANES 2008-2011.

    Science.gov (United States)

    Lee, Ji Hyun; Hong, A Ram; Kim, Jung Hee; Kim, Kyoung Min; Koo, Bo Kyung; Shin, Chan Soo; Kim, Sang Wan

    2018-01-01

    Smoking induces bone loss; however, data on the relationship between smoking history and bone mineral density (BMD) are lacking. Age and pulmonary function can affect BMD. We investigated the relationships among pack-years (PYs) of smoking, pulmonary function, and BMD in middle-aged Korean men (50-64 years old). This cross-sectional study used data from the Korean National Health and Nutrition Examination Survey, 2008-2011. All participants underwent BMD measurements using dual energy X-ray absorptiometry and pulmonary function tests using standardized spirometry. In total, 388 never-smokers and 1088 ever-smokers were analyzed. The number of PYs of smoking was negatively correlated with total hip BMD (r = -0.088; P = 0.004) after adjusting for age, height, and weight. Ever-smokers were classified into 3 groups according to PYs of smoking. The highest tertile (n = 482) exhibited significantly lower total hip bone mass than the lowest tertile (n = 214) after adjusting for confounding factors (age, height, weight, forced expiratory volume in 1 s (FEV 1 ), alcohol consumption, physical activity, and vitamin D levels) that could affect bone metabolism (P = 0.003). In conclusion, smoking for >30 PYs was significantly associated with low hip BMD after adjusting for pulmonary function in middle-aged Korean men. Long-term smoking may be a risk factor for bone loss in middle-aged men independent of age, height, weight, and pulmonary function.

  6. Assessing the origin of old apparent ages derived by Pb stepwise leaching of vein-hosted epidote from Mount Isa, northwest Queensland, Australia

    Science.gov (United States)

    Duncan, Robert J.; Maas, Roland

    2014-12-01

    Epidote metasomatism affected large areas of tholeiitic metabasalts of the ~1,780 Ma Eastern Creek Volcanics in the Western Fold Belt of the Proterozoic Mount Isa inlier. Hydrothermal epidote generally occurs in quartz veins parallel to or boudinaged within the dominant S2 fabrics which formed during the regional metamorphic peak at ~1,570 Ma associated with the Isan orogeny. Previously published stable isotopic and halogen data suggest that the fluids responsible for epidote formation are metamorphic in origin (with an evaporitic component). Application of the Pb stepwise leaching technique to the epidote does not separate radiogenic Pb4+ and common Pb2+, generating little spread in 206Pb/204Pb (between 16.0 and 30.5). The causes for this relatively low range are twofold: There is little radiogenic Pb in the epidotes (the most radiogenic steps account for leaching data give ages between 150 and 1,500 myrs older than the host rocks and over 450 myrs older than the thermal metamorphic peak. These old ages are attributed to chemical inheritance from the host metabasalts, via radiogenic Pb release by breakdown of phases such as zircon, monazite, titanomagnetite, and ilmenite during metamorphism. This idea is supported by trace element data and chrondrite-normalized rare earth element patterns that are similar to both the metabasalts and epidotes (except for a variable Eu anomaly in the latter). Relatively high fO2 during vein formation (Fe3+ dominates in the epidote crystal lattice) would allow the incorporation of Th4+ and exclusion of U6+ and would explain elevated Th/U ratios (up to 12) in epidote compared with the host metabasalts. Non-incorporation of U would explain the relatively low U/Pb ratios and non-radiogenic character of the epidote. This process may provide a source of metal for the small U deposits around Mount Isa and may also suggest a relationship between U mineralization and regional Cu mobilization during the Isan orogeny. Our work suggests that

  7. Effects of emission layer doping on the spatial distribution of charge and host recombination rate density in organic light emitting devices: A numerical study

    Science.gov (United States)

    Li, Yanli; Zhou, Maoqing; Zheng, Tingcai; Yao, Bo; Peng, Yingquan

    2013-12-01

    Based on drift-diffusion theory, a numerical model of the doping of a single energy level trap in the emission layer of an organic light emitting device (OLED) was developed, and the effects of doping of this single energy level trap on the distribution of the charge density, the recombination rate density, and the electric field in single- and double-layer OLEDs were studied numerically. The results show that by doping the n-type (p-type) emission layer with single energy electron (hole) traps, the distribution of the recombination rate density can be tuned and shifted, which is useful for improvement of the device performance by reduced electrode quenching or for realization of desirable special functions, e.g., emission spectrum tuning in multiple dye-doped white OLEDs.

  8. Effects of emission layer doping on the spatial distribution of charge and host recombination rate density in organic light emitting devices: A numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yanli; Zhou, Maoqing; Zheng, Tingcai; Yao, Bo [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Peng, Yingquan, E-mail: yqpeng@lzu.edu.cn [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2013-12-28

    Based on drift-diffusion theory, a numerical model of the doping of a single energy level trap in the emission layer of an organic light emitting device (OLED) was developed, and the effects of doping of this single energy level trap on the distribution of the charge density, the recombination rate density, and the electric field in single- and double-layer OLEDs were studied numerically. The results show that by doping the n-type (p-type) emission layer with single energy electron (hole) traps, the distribution of the recombination rate density can be tuned and shifted, which is useful for improvement of the device performance by reduced electrode quenching or for realization of desirable special functions, e.g., emission spectrum tuning in multiple dye-doped white OLEDs.

  9. Effects of emission layer doping on the spatial distribution of charge and host recombination rate density in organic light emitting devices: A numerical study

    International Nuclear Information System (INIS)

    Li, Yanli; Zhou, Maoqing; Zheng, Tingcai; Yao, Bo; Peng, Yingquan

    2013-01-01

    Based on drift-diffusion theory, a numerical model of the doping of a single energy level trap in the emission layer of an organic light emitting device (OLED) was developed, and the effects of doping of this single energy level trap on the distribution of the charge density, the recombination rate density, and the electric field in single- and double-layer OLEDs were studied numerically. The results show that by doping the n-type (p-type) emission layer with single energy electron (hole) traps, the distribution of the recombination rate density can be tuned and shifted, which is useful for improvement of the device performance by reduced electrode quenching or for realization of desirable special functions, e.g., emission spectrum tuning in multiple dye-doped white OLEDs

  10. The use of bone age for bone mineral density interpretation in a cohort of pediatric brain tumor patients

    International Nuclear Information System (INIS)

    Morris, E.B.; Shelso, John; Smeltzer, Matthew P.; Li, Chin-Shang; Thomas, Nicole A.; Karimova, E.J.; Merchant, Thomas; Gajjar, Amar; Kaste, Sue C.

    2008-01-01

    Skeletal bone accretion occurs throughout childhood. The integrity of this process can influence future adult bone health and the risk of osteoporosis. Although surveillance of children who are at risk of poor bone accretion is important, the most appropriate method to monitor childhood bone health has not been established. Previous investigators have proposed using bone age (BA) rather than chronological age (CA) when interpreting bone mineral density (BMD) values in children. To investigate the value of BA assessment for BMD measurement in a cohort of children at risk of poor accretion. A cohort of 163 children with brain tumors who completed both a BMD assessment (quantitative computed tomography, QCT) and who had a BA within a 6-month interval were identified. The difference in BMD Z-scores determined by CA and BA was determined. The impact of salient clinical features was assessed. No significant difference between CA and BA Z-scores was detected in the overall cohort (P 0.056). However, the scores in 18 children (all boys between the ages of 11 years and 15 years) were statistically determined to be outliers from the values in the rest of the cohort. Interpretation of BMD with BA measurement might be appropriate and affect treatment decisions in peripubertal males. (orig.)

  11. Correlation analysis between bone density measured by quantitative CT and blood sugar level of aged patients with non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Wang Guizhi; Liang Ping; Qiao Junhua; Liu Chunyan

    2008-01-01

    Objective: To approach the correlation between the bone density measured by quantitative CT and the blood sugar level of the aged patients with non-insulin-dependent diabetes mellitus, and observe the effects of the blood sugar level on the bone density. Methods: The lumbar bone densities and the blood sugar levels of 160 aged patients with non-insulin-dependent diabetes mellitus (hyperglycemia group 80 cases, euglycemia group 80 cases ) and the healthy aged people (80 cases) were detected by quantitative CT and serum biochemical detection; the correlation between the blood sugar level and the bone density and the osteoporosis occurrence status of aged people in various groups were analyzed. Results: The bone density in the non-insulin-dependent diabetes and hyperglycemia group was lower than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); the morbility of osteoporosis in the non-insulin-dependent diabetes and hyperglycemia group was higher than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); negative correlation was found between the bone density and the blood sugar level (aged male group: r=-0.7382, P=0.0013; aged female group: r=-0.8343, P=0.0007). Conclusion: The blood sugar level affects the bone density of the aged patients with non-insulin-dependent diabetes mellitus; the higher the blood sugar level, the lower the bone density. The non-insulin-dependent diabetes aged patients with hyperglycemia have the liability of osteoporosis. (authors)

  12. Aging memory for pictures: using high-density event-related potentials to understand the effect of aging on the picture superiority effect.

    Science.gov (United States)

    Ally, Brandon A; Waring, Jill D; Beth, Ellen H; McKeever, Joshua D; Milberg, William P; Budson, Andrew E

    2008-01-31

    High-density event-related potentials (ERPs) were used to understand the effect of aging on the neural correlates of the picture superiority effect. Pictures and words were systematically varied at study and test while ERPs were recorded at retrieval. Here, the results of the word-word and picture-picture study-test conditions are presented. Behavioral results showed that older adults demonstrated the picture superiority effect to a greater extent than younger adults. The ERP data helped to explain these findings. The early frontal effect, parietal effect, and late frontal effect were all indistinguishable between older and younger adults for pictures. In contrast, for words, the early frontal and parietal effects were significantly diminished for the older adults compared to the younger adults. These two old/new effects have been linked to familiarity and recollection, respectively, and the authors speculate that these processes are impaired for word-based memory in the course of healthy aging. The findings of this study suggest that pictures allow older adults to compensate for their impaired memorial processes, and may allow these memorial components to function more effectively in older adults.

  13. Effect of age, photoperiod and host availability on the parasitism behavior of Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae); Efeito da idade, fotoperiodo e disponibilidade de hospedeiro no comportamento de parasitismo de Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae)

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Torres, Christian S.A.; Barros, Reginaldo; Torres, Jorge B. [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Dept. de Agronomia - Entomologia], e-mail: sherleyjbt@yahoo.com

    2009-07-15

    The high reproduction rate, potential to cause damage, wide geographic distribution and resistance to insecticides of Plutella xylostella (L.) makes difficult its efficient control. However, larvae and pupae of this pest are naturally parasitized by Oomyzus Sokolowskii (Kurdjumov), providing opportunities to improve the natural parasitism. This study investigated the effects of the age of adult parasitoids, host availability and time of exposure on O. sokolowskii parasitism behavior. The number of larvae encounters by parasitoid females and the parasitism rate increased with parasitoid age up to 96 h. The parasitization was higher when wasps received a constant number of hosts daily in comparison with a random number (13.3 versus 8.9 larvae parasitized). Female parasitization activity was maintained up to the age of 20 days in both treatments and exhibited similar longevity (constant host = 33.5 d; and random host = 34.7 d). The progeny produced per female and the number of parasitoids emerged per host significantly decreased as wasps aged. There was no significant effect of the light regime (12 h darkness or 12 h light exposure) on the parasitization, although parasitoid was more active after 3 h of light exposure. Therefore, further studies on field application of O. sokolowskii should consider the release of 48 h - to 72 h - old parasitoids at dawn as a way to increase the success of host parasitization. (author)

  14. The relationship between BPAQ-derived physical activity and bone density of middle-aged and older men.

    Science.gov (United States)

    Bolam, K A; Beck, B R; Adlard, K N; Skinner, T L; Cormie, P; Galvão, D A; Spry, N; Newton, R U; Taaffe, D R

    2014-11-01

    The bone-specific physical activity questionnaire (BPAQ) accounts for activities that affect bone but has not been used in studies with older adults. Relationships exist between the BPAQ-derived physical activity and bone density in healthy middle-aged and older men but not men with prostate cancer. Disease-related treatments detrimental to bone should be considered when administering the BPAQ. The bone-specific physical activity questionnaire (BPAQ) was developed to account for bone-specific loading. In this retrospective study, we examined the relationship between BPAQ-derived physical activity and bone mineral density (BMD) in middle-aged and older men with and without prostate cancer. Two groups, 36 healthy men and 69 men with prostate cancer receiving androgen suppression therapy (AST), completed the BPAQ and had whole body, total hip, femoral (FN) and lumbar spine BMD assessed by dual-energy X-ray absorptiometry. Past (pBPAQ), current (cBPAQ) and total BPAQ (tBPAQ) scores for the healthy men were related to FN BMD (pBPAQ r = 0.36, p = 0.030; cBPAQ r s = 0.35, p = 0.034; tBPAQ r = 0.41, p = 0.014), and pBPAQ and tBPAQ were related to total hip (r s = 0.35, p = 0.035 and r s = 0.36, p = 0.029, respectively) and whole body BMD (r s = 0.44, p = 0.007 and r s = 0.45, p = 0.006, respectively). In men with prostate cancer, the BPAQ was not significantly associated with BMD. In stepwise regression analyses, body mass and tBPAQ predicted 30 % of the variance in total hip BMD (p = 0.003), cBPAQ predicted 14 % of the variance in FN BMD (p = 0.002), and body mass, age and tBPAQ predicted 47% of the variance in whole body BMD (p men. In men with prostate cancer, the BPAQ was not an independent predictor of BMD. Although BPAQ-derived estimates of physical activity are related to bone status in healthy middle-aged and older men, the adverse effect of AST on bone appears to obscure this relationship in men

  15. Effect of basal metabolic rate on the bone mineral density in middle to old age women in Taiwan.

    Science.gov (United States)

    Hsu, Wei-Hsiu; Fan, Chun-Hao; Lin, Zin-Rong; Hsu, Robert Wen-Wei

    2013-09-01

    Basal metabolic rate (BMR) reflects a combination of cardiopulmonary function and lean body mass resulting from regular physical activity. Though many studies have examined the relationships between bone mineral density (BMD) and body composition, little is known regarding the relationship between BMD and BMR. The purpose of this study was to investigate the relationship between BMR, anthropometric parameters, body composition and BMD in postmenopausal women in Taiwan. Two hundred and eighty-nine women between the ages of 40 and 80 years were included in this cross-sectional study. The following parameters were assessed: height, body weight, total body fat (TBF), BMR, waist-to-hip ratio, grip strength, and back strength. Differences in all variables between osteoporotic and non-osteoporotic women (categorized according to decades in age) were calculated using a one-way analysis of variance (ANOVA) and a Bonferroni post-hoc test. Multiple linear regression with a backward stepwise approach was performed to evaluate the relationship between these measurements and BMD. Among women over 50 years of age, those who were non-osteoporotic had higher BMR, BMI, and body fat by comparison to their osteoporotic counterparts (pBMR and body fat significantly predicted BMD of the femoral neck (adjusted beta coefficients of 0.304 and 0.190, respectively; pBMR and body fat also predicted an increased vertebral BMD (adjusted beta coefficients of 0.310 and 0.141, respectively; pBMR is closely associated with BMD in elderly persons, and may be a novel target for interventions aimed at preventing the age-related decline in BMD. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Bone Mineral Density in Gravida: Effect of Pregnancies and Breast-Feeding in Women of Differing Ages and Parity

    Directory of Open Access Journals (Sweden)

    Ehud Lebel

    2014-01-01

    Full Text Available Changes of bone during pregnancy and during lactation evaluated by bone mineral density (BMD may have implications for risk of osteoporosis and fractures. We studied BMD in women of differing ages, parity, and lactation histories immediately postpartum for BMD, T-scores, and Z-scores. Institutional Review Board approval was received. All women while still in hospital postpartum were asked to participate. BMD was performed by dual-energy X-ray absorptiometry (DXA machine at femoral neck (FN and lumbar spine (LS by a single technician. Of 132 participants, 73 (55.3% were ≤30 years; 27 (20.5% were primiparous; 36 (27.3% were grand multiparous; 35 (26.5% never breast fed. Mean FN T-scores and Z-scores were higher than respective mean LS scores, but all means were within the normal limits. Mean LS T-scores and Z-scores were highest in the grand multiparas. There were only 2 (1.5% outliers with low Z-scores. We conclude that, in a large cohort of Israeli women with BMD parameters assessed by DXA within two days postpartum, mean T-scores and Z-scores at both the LS and FN were within normal limits regardless of age (20–46 years, parity (1–13 viable births, and history of either no or prolonged months of lactation (up to 11.25 years.

  17. Computed tomographic analysis of tibiotarsal bone mineral density and content in turkeys as influenced by age and sex

    International Nuclear Information System (INIS)

    Charuta, A.; Cooper, R.G.; Pierzchala, M.; Horbanczuk, J.O.

    2012-01-01

    Changes in the volumetric bone mineral density (vBMD) and bone mineral content (BMC) of tibiotarsal bones of growing turkeys as affected by birds' age, sex, and within-the-bone location, respectively, were determined by computed tomography. The research was performed on 165 heavy-type BIG 6 turkeys reared between weeks (wk) 3-16 of age. The computed tomography measurement, conducted at 18 and 50% of the bone length, comprised a bone fragment which was 0.07 mm thick for the compact and the spongious substance collectively. It should be noted that the diaphyses of the tibiotarsal bones in turkeys (580 mg/cubic cm) had significantly greater vBMD than the proximal metaphyses (300 mg/cubic cm). BMC was higher in metaphyses for both sexes. Significant differences between the BMC of the metaphyses and the diaphyses were observed in males and females at wk 3, 6 and 9, and at wk 3 and 12, respectively. vBMD in the diaphyses gradually attenuated with age for both sexes, from 688 mg/cubic cm (wk 3) to 532 mg/cubic cm (wk 16). vBMD of the metaphyses was constant in females, but in males it achieved maximum values of 350 mg/cubic cm at wk 6 and 12 and minimum of 260 mg/cubic cm at wk 9 and 16. Correlations between body weight and vBMD of the diaphyses were observed in males (r = -0.85, P less than 0.001) and females (r = -0.52, P less than 0.01). It can be concluded that vBMD loss in diaphyses diminished bone-breaking strength leading in investigated turkeys to deformities and bone fractures

  18. Vitamin D intake, month the mammogram was taken and mammographic density in Norwegian women aged 50-69.

    Directory of Open Access Journals (Sweden)

    Merete Ellingjord-Dale

    Full Text Available The role of vitamin D in breast cancer etiology is unclear. There is some, but inconsistent, evidence that vitamin D is associated with both breast cancer risk and mammographic density (MD. We evaluated the associations of MD with month the mammogram was taken, and with vitamin D intake, in a population of women from Norway--a country with limited sunlight exposure for a large part of the year.3114 women aged 50-69, who participated in the Norwegian Breast Cancer Screening Program (NBCSP in 2004 or 2006/07, completed risk factor and food frequency (FFQ questionnaires. Dietary and total (dietary plus supplements vitamin D, calcium and energy intakes were estimated by the FFQ. Month when the mammogram was taken was recorded on the mammogram. Percent MD was assessed using a computer assisted method (Madena, University of Southern California after digitization of the films. Linear regression models were used to investigate percent MD associations with month the mammogram was taken, and vitamin D and calcium intakes, adjusting for age, body mass index (BMI, study year, estrogen and progestin therapy (EPT, education, parity, calcium intakes and energy intakes.There was no statistical significant association between the month the mammogram was taken and percent MD. Overall, there was no association between percent MD and quartiles of total or dietary vitamin D intakes, or of calcium intake. However, analysis restricted to women aged <55 years revealed a suggestive inverse association between total vitamin D intake and percent MD (p for trend = 0.03.Overall, we found no strong evidence that month the mammogram was taken was associated with percent MD. We found no inverse association between vitamin D intake and percent MD overall, but observed a suggestive inverse association between dietary vitamin D and MD for women less than 55 years old.

  19. Body composition and circulating estradiol are the main bone density predictors in healthy young and middle-aged men.

    Science.gov (United States)

    Bilha, S C; Branisteanu, D; Buzduga, C; Constantinescu, D; Cianga, P; Anisie, E; Covic, A; Ungureanu, M C

    2018-01-16

    Current fracture risk assessment options in men call for improved evaluation strategies. Recent research directed towards non-classic bone mass determinants have often yielded scarce and conflicting results. We aimed at investigating the impact of novel potential bone mass regulators together with classic determinants of bone status in healthy young and middle-aged men. Anthropometric measurements, all-site bone mineral density (BMD) and body composition parameters assessed by dual-energy X-ray absorptiometry and also serum concentrations of (1) the adipokines leptin and resistin, (2) vitamin D and parathormone (PTH), (3) sex hormone binding globulin (SHBG), total testosterone and estradiol (free testosterone was also calculated) and (4) C-terminal telopeptide of type I collagen (CTx) were obtained from 30 apparently healthy male volunteers aged 20-65 years enrolled in this cross-sectional study. Only lean mass (LM) and total estradiol independently predicted BMD in men in multiple regression analysis, together explaining 49% (p ≤ 0.001) of whole-body BMD variance. Hierarchical regression analysis with whole-body BMD as outcome variable demonstrated that the body mass index (BMI) beta coefficient became nonsignificant when LM was added to the model. Adipokines, fat parameters, testosterone (total and free), SHBG, PTH and vitamin D were not independently associated with BMD or CTx. The present study shows that LM and sex hormones-namely estradiol-are the main determinants of bone mass in young and middle-aged men. The effects of BMI upon BMD seem to be largely mediated by LM. Lifestyle interventions should focus on preserving LM in men for improved bone outcomes.

  20. Age-related changes in bone biochemical markers and their relationship with bone mineral density in normal Chinese women.

    Science.gov (United States)

    Pi, Yin-Zhen; Wu, Xian-Ping; Liu, Shi-Ping; Luo, Xiang-Hang; Cao, Xing-Zhi; Xie, Hui; Liao, Er-Yuan

    2006-01-01

    Measurements of bone biochemical markers are increasingly being used to evaluate the state of bone turnover in the management of bone metabolic diseases, especially osteoporosis. However, changes in the bone turnover rate vary with age. The aim of this study was to establish the laboratory reference range of serum bone-specific alkaline phosphatase (sBAP), serum type I collagen cross-linked C-terminal telopeptide (sCTx), and urine CTx (uCTx), based on values from 665 healthy Chinese women aged 20-80 years. We measured the levels of sBAP, sCTx, serum alkaline phosphatase (sALP), and uCTx and evaluated the age-related changes and their relationship with bone mineral density (BMD) in the anteroposterior (AP) lumbar spine, hip, and left forearm. We found significant correlations between biochemical markers and age, with coefficients of determination (R (2)) of 0.358 for sBAP, 0.126 for sCTx, 0.125 for uCTx, and 0.336 for sALP. The net changes in different biochemical markers were inversely correlated with the rates of BMD loss in the AP lumbar spine. After correction for age, body weight, and height, the levels of the markers had significant negative correlations with the BMD of the AP lumbar spine, femoral neck, and ultradistal forearm. All four biochemical markers had the highest negative correlation with BMD of the AP lumbar spine (partial correlation coefficients of -0.366, -0.296, -0.290, and -0.258 for sBAP, sCTx, uCTx, and sALP, respectively). The mean and SD values of these markers in premenopausal and postmenopausal women with normal BMD values were used as the normal reference ranges. The reference ranges of sBAP, sCTx, and uCTx for pre- vs postmenopausal women were 17.3 +/- 6.23 vs 18.9 +/- 7.52 U/l, 3.18 +/- 1.49 vs 3.23 +/- 1.57 nmol/l, and 15.5 +/- 11.4 vs 16.2 +/- 12.4 nM bone collagen equivalents/mM urinary creatinine, respectively. Levels of the bone formation marker (sBAP) and bone resorption markers (sCTx, uCTx) increased rapidly in women with

  1. Effect of mixed hole transporting host on the mobility, Gaussian density of states and efficiencies of a heterojunction phosphorescent organic light emitting diode

    International Nuclear Information System (INIS)

    Talik, N A; Woon, K L; Yap, B K

    2016-01-01

    We present an in-depth study of the hole transport in poly(vinylcarbazole) PVK films blended with small molecule tris(4-carbazoyl-9-ylphenyl)amine (TcTa). Doping TcTa in PVK introduces shallow hole traps when the doping concentration is lower than 20 wt%. It becomes percolative at higher concentrations. The energetic disorder σ of the blended system reduces from ∼72 meV at 0 wt% TcTa to ∼41 meV at 50 wt% TcTa. A correlation between σ and the film morphologies suggests that the blending of TcTa molecules in the film does not only change the film homogeneity and roughness but also the energetic disorder. In addition to the mobility study, we fabricated a red phosphorescent organic light emitting diode with the same blending system. By doping merely 5 wt% of TcTa into PVK as mixed hole-transporting hosts, the efficiency of the deep red heterojunction phosphorescent organic light emitting diode increased from 2 cd A −1 to 4 cd A −1 , suggesting that TcTa molecules assist in hole injection. (paper)

  2. Probability of Transmission of Malaria from Mosquito to Human Is Regulated by Mosquito Parasite Density in Naïve and Vaccinated Hosts.

    Directory of Open Access Journals (Sweden)

    Thomas S Churcher

    2017-01-01

    Full Text Available Over a century since Ronald Ross discovered that malaria is caused by the bite of an infectious mosquito it is still unclear how the number of parasites injected influences disease transmission. Currently it is assumed that all mosquitoes with salivary gland sporozoites are equally infectious irrespective of the number of parasites they harbour, though this has never been rigorously tested. Here we analyse >1000 experimental infections of humans and mice and demonstrate a dose-dependency for probability of infection and the length of the host pre-patent period. Mosquitoes with a higher numbers of sporozoites in their salivary glands following blood-feeding are more likely to have caused infection (and have done so quicker than mosquitoes with fewer parasites. A similar dose response for the probability of infection was seen for humans given a pre-erythrocytic vaccine candidate targeting circumsporozoite protein (CSP, and in mice with and without transfusion of anti-CSP antibodies. These interventions prevented infection more efficiently from bites made by mosquitoes with fewer parasites. The importance of parasite number has widespread implications across malariology, ranging from our basic understanding of the parasite, how vaccines are evaluated and the way in which transmission should be measured in the field. It also provides direct evidence for why the only registered malaria vaccine RTS,S was partially effective in recent clinical trials.

  3. Age and geochemistry of host rocks of the Cobre Panama porphyry Cu-Au deposit, central Panama: Implications for the Paleogene evolution of the Panamanian magmatic arc

    Science.gov (United States)

    Baker, Michael J.; Hollings, Peter; Thompson, Jennifer A.; Thompson, Jay M.; Burge, Colin

    2016-04-01

    The Cobre Panama porphyry Cu-Au deposit, located in the Petaquilla district of central Panama, is hosted by a sequence of medium- to high-K calc-alkaline volcanic and sub-volcanic rocks. New crystallisation ages obtained from a granodiorite Petaquilla batholith and associated mineralised diorite to granodiorite porphyry stocks and dikes at Cobre Panama indicate that the batholith was emplaced as a multi-phase intrusion, over a period of 4 million years from 32.20 ± 0.76 Ma to 28.26 ± 0.61 Ma, while the porphyritic rocks were emplaced over a 2 million year period from 28.96 ± 0.62 Ma to 27.48 ± 0.68 Ma. Both the volcanic to sub-volcanic host rocks and intrusive rocks of the Cobre Panama deposit evolved via fractional crystallisation processes, as demonstrated by the major elements (e.g. Al2O3, Fe2O3, TiO2 and MgO) displaying negative trends with increasing SiO2. The Petaquilla intrusive rocks, including the diorite-granodiorite porphyries and granodiorite batholith, are geochemically evolved and appear to have formed from more hydrous magmas than the preceding host volcanic rocks, as evidenced by the presence of hornblende phenocrysts, higher degrees of large-ion lithophile element (LILE) and light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion, and higher Sr/Y and La/Yb values. However, the degree of LREE enrichment, HREE depletion and La/Yb values are insufficient for the intrusive rocks to be considered as adakites. Collectively, the volcanic and intrusive rocks have LILE, REE and mobile trace element concentrations similar to enriched Miocene-age Cordilleran arc magmatism found throughout central and western Panama. Both the Petaquilla and Cordilleran arc magmatic suites are geochemically more evolved than the late Cretaceous to Eocene Chagres-Bayano arc magmas from northeastern Panama, as they display higher degrees of LILE and LREE enrichment. The geochemical similarities between the Petaquilla and Cordilleran arc magmas

  4. Change in bone mineral density as a function of age in women and men and association with the use of antiresorptive agents.

    Science.gov (United States)

    Berger, Claudie; Langsetmo, Lisa; Joseph, Lawrence; Hanley, David A; Davison, K Shawn; Josse, Robert; Kreiger, Nancy; Tenenhouse, Alan; Goltzman, David

    2008-06-17

    Measurement of bone mineral density is the most common method of diagnosing and assessing osteoporosis. We sought to estimate the average rate of change in bone mineral density as a function of age among Canadians aged 25-85, stratified by sex and use of antiresorptive agents. We examined a longitudinal cohort of 9423 participants. We measured the bone mineral density in the lumbar spine, total hip and femoral neck at baseline in 1995-1997, and at 3-year (participants aged 40-60 years only) and 5-year follow-up visits. We used the measurements to compute individual rates of change. Bone loss in all 3 skeletal sites began among women at age 40-44. Bone loss was particularly rapid in the total hip and was greatest among women aged 50-54 who were transitioning from premenopause to postmenopause, with a change from baseline of -6.8% (95% confidence interval [CI] -7.5% to -4.9%) over 5 years. The rate of decline, particularly in the total hip, increased again among women older than 70 years. Bone loss in all 3 skeletal sites began at an earlier age (25-39) among men than among women. The rate of decline of bone density in the total hip was nearly constant among men 35 and older and then increased among men older than 65. Use of antiresorptive agents was associated with attenuated bone loss in both sexes among participants aged 50-79. The period of accelerated loss of bone mineral density in the hip bones occurring among women and men older than 65 may be an important contributor to the increased incidence of hip fracture among patients in that age group. The extent of bone loss that we observed in both sexes indicates that, in the absence of additional risk factors or therapy, repeat testing of bone mineral density to diagnose osteoporosis could be delayed to every 5 years.

  5. The Effect of Age, Stocking Density and Flooring during Transport on Welfare of Young Dairy Calves in Australia

    Directory of Open Access Journals (Sweden)

    Ellen C. Jongman

    2014-04-01

    Full Text Available Transport of young (‘bobby’ calves for slaughter is a contentious welfare issue for some sectors of the Australian community. Factors of age, stocking density and flooring need further research to develop appropriate welfare standards for transport of bobby calves. The objective of this study was to identify the space allowance requirements for transport of bobby calves and to understand factors such as age and flooring that minimise risks to calf welfare during transport. Animals aged 3-, 5- and 10-day old were transported for 12 h in a custom-made cattle truck fitted with 9 pens, with movable mesh divisions. Each pen contained 4 calves, with space allowances of 0.2, 0.3 and 0.5 m2 per calf and flooring of solid metal, mesh or straw bedding. A total of 432 male dairy calves were transported in 12 trips during the 2-year study. Behavioural measurements included lying during transport, and lying and drinking for 12 h after transport during recovery. Blood samples were taken prior to transport, immediately after transport and 12 h after transport. Blood samples were analysed for metabolic state (glucose, beta-hydroxy-butyrate (BOHB, hydration (packed cell volume (PCV and exhaustion/bruising (creatine kinase (CK activity. It was found that several measures were affected by age, which indicates that the physiology and in particular lying behaviour of 3-day old calves is fundamentally different from that of older calves. It is unclear how this affects their ability to cope with the stressors of transport. Space affected the posture changes and CK activity during and after transport and it is concluded that space allowance should be at least 0.3 m2 per calf for calves of average size, while CK activity suggested that providing more space to 0.5 m2 per calf may provide even greater benefits. Straw bedding is of clear benefit to calves during transport, to the extent that it may even reduce some of the negative effects of reduced space on lying

  6. Relationship of blood and bone lead to menopause and bone mineral density among middle-age women in Mexico City.

    Science.gov (United States)

    Garrido Latorre, Francisco; Hernández-Avila, Mauricio; Tamayo Orozco, Juan; Albores Medina, Carlos A; Aro, Antonio; Palazuelos, Eduardo; Hu, Howard

    2003-04-01

    To describe the relationship of blood lead levels to menopause and bone lead levels, we conducted a cross-sectional study on 232 pre- or perimenopausal (PreM) and postmenopausal (PosM) women who participated in an osteoporosis-screening program in Mexico City during the first quarter of 1995. Information regarding reproductive characteristics and known risk factors for blood lead was obtained using a standard questionnaire by direct interview. The mean age of the population was 54.7 years (SD = 9.8), with a mean blood lead level of 9.2 microg/dL (SD = 4.7/dL) and a range from 2.1 to 32.1 microg/dL. After adjusting for age and bone lead levels, the mean blood lead level was 1.98 microg/dL higher in PosM women than in PreM women (p = 0.024). The increase in mean blood lead levels peaked during the second year of amenorrhea with a level (10.35 microg/dL) that was 3.51 microg/dL higher than that of PreM women. Other important predictors of blood lead levels were use of lead-glazed ceramics, schooling, trabecular bone lead, body mass index, time of living in Mexico City, and use of hormone replacement therapy. Bone density was not associated with blood lead levels. These results support the hypothesis that release of bone lead stores increases during menopause and constitutes an internal source of exposure possibly associated with health effects in women in menopause transition.

  7. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a ...

  8. Breast Density Awareness and Knowledge, and Intentions for Breast Cancer Screening in a Diverse Sample of Women Age Eligible for Mammography.

    Science.gov (United States)

    Santiago-Rivas, Marimer; Benjamin, Shayna; Andrews, Janna Z; Jandorf, Lina

    2017-08-14

    The objectives of this study were to assess breast density knowledge and breast density awareness, and to identify information associated with intention to complete routine and supplemental screening for breast cancer in a diverse sample of women age eligible for mammography. We quantitatively (self-report) assessed breast density awareness and knowledge (N = 264) in black (47.7%), Latina (35.2%), and white (17%) women recruited online and in the community. Most participants reported having heard about breast density (69.2%); less than one third knew their own breast density status (30.4%). Knowing their own breast density, believing that women should be notified of their breast density in their mammogram report, and feeling informed if being provided this information are associated with likelihood of completing mammogram. Intending mammogram completion and knowledge regarding the impact of breast density on mammogram accuracy are associated with likelihood of completing supplemental ultrasound tests of the breast. These findings help inform practitioners and policy makers about information and communication factors that influence breast cancer screening concerns and decisions. Knowing this information should prepare practitioners to better identify women who may have not been exposed to breast density messages.

  9. Linear and curvilinear correlations of brain gray matter volume and density with age using voxel-based morphometry with the Akaike information criterion in 291 healthy children.

    Science.gov (United States)

    Taki, Yasuyuki; Hashizume, Hiroshi; Thyreau, Benjamin; Sassa, Yuko; Takeuchi, Hikaru; Wu, Kai; Kotozaki, Yuka; Nouchi, Rui; Asano, Michiko; Asano, Kohei; Fukuda, Hiroshi; Kawashima, Ryuta

    2013-08-01

    We examined linear and curvilinear correlations of gray matter volume and density in cortical and subcortical gray matter with age using magnetic resonance images (MRI) in a large number of healthy children. We applied voxel-based morphometry (VBM) and region-of-interest (ROI) analyses with the Akaike information criterion (AIC), which was used to determine the best-fit model by selecting which predictor terms should be included. We collected data on brain structural MRI in 291 healthy children aged 5-18 years. Structural MRI data were segmented and normalized using a custom template by applying the diffeomorphic anatomical registration using exponentiated lie algebra (DARTEL) procedure. Next, we analyzed the correlations of gray matter volume and density with age in VBM with AIC by estimating linear, quadratic, and cubic polynomial functions. Several regions such as the prefrontal cortex, the precentral gyrus, and cerebellum showed significant linear or curvilinear correlations between gray matter volume and age on an increasing trajectory, and between gray matter density and age on a decreasing trajectory in VBM and ROI analyses with AIC. Because the trajectory of gray matter volume and density with age suggests the progress of brain maturation, our results may contribute to clarifying brain maturation in healthy children from the viewpoint of brain structure. Copyright © 2012 Wiley Periodicals, Inc.

  10. Tailoring Breast Cancer Screening Intervals by Breast Density and Risk for Women Aged 50 Years or Older: Collaborative Modeling of Screening Outcomes.

    Science.gov (United States)

    Trentham-Dietz, Amy; Kerlikowske, Karla; Stout, Natasha K; Miglioretti, Diana L; Schechter, Clyde B; Ergun, Mehmet Ali; van den Broek, Jeroen J; Alagoz, Oguzhan; Sprague, Brian L; van Ravesteyn, Nicolien T; Near, Aimee M; Gangnon, Ronald E; Hampton, John M; Chandler, Young; de Koning, Harry J; Mandelblatt, Jeanne S; Tosteson, Anna N A

    2016-11-15

    Biennial screening is generally recommended for average-risk women aged 50 to 74 years, but tailored screening may provide greater benefits. To estimate outcomes for various screening intervals after age 50 years based on breast density and risk for breast cancer. Collaborative simulation modeling using national incidence, breast density, and screening performance data. United States. Women aged 50 years or older with various combinations of breast density and relative risk (RR) of 1.0, 1.3, 2.0, or 4.0. Annual, biennial, or triennial digital mammography screening from ages 50 to 74 years (vs. no screening) and ages 65 to 74 years (vs. biennial digital mammography from ages 50 to 64 years). Lifetime breast cancer deaths, life expectancy and quality-adjusted life-years (QALYs), false-positive mammograms, benign biopsy results, overdiagnosis, cost-effectiveness, and ratio of false-positive results to breast cancer deaths averted. Screening benefits and overdiagnosis increase with breast density and RR. False-positive mammograms and benign results on biopsy decrease with increasing risk. Among women with fatty breasts or scattered fibroglandular density and an RR of 1.0 or 1.3, breast cancer deaths averted were similar for triennial versus biennial screening for both age groups (50 to 74 years, median of 3.4 to 5.1 vs. 4.1 to 6.5 deaths averted; 65 to 74 years, median of 1.5 to 2.1 vs. 1.8 to 2.6 deaths averted). Breast cancer deaths averted increased with annual versus biennial screening for women aged 50 to 74 years at all levels of breast density and an RR of 4.0, and those aged 65 to 74 years with heterogeneously or extremely dense breasts and an RR of 4.0. However, harms were almost 2-fold higher. Triennial screening for the average-risk subgroup and annual screening for the highest-risk subgroup cost less than $100 000 per QALY gained. Models did not consider women younger than 50 years, those with an RR less than 1, or other imaging methods. Average-risk women

  11. A case-control study to assess the impact of mammographic density on breast cancer risk in women aged 40-49 at intermediate familial risk.

    Science.gov (United States)

    Assi, Valentina; Massat, Nathalie J; Thomas, Susan; MacKay, James; Warwick, Jane; Kataoka, Masako; Warsi, Iqbal; Brentnall, Adam; Warren, Ruth; Duffy, Stephen W

    2015-05-15

    Mammographic density is a strong risk factor for breast cancer, but its potential application in risk management is not clear, partly due to uncertainties about its interaction with other breast cancer risk factors. We aimed to quantify the impact of mammographic density on breast cancer risk in women aged 40-49 at intermediate familial risk of breast cancer (average lifetime risk of 23%), in particular in premenopausal women, and to investigate its relationship with other breast cancer risk factors in this population. We present the results from a case-control study nested with the FH01 cohort study of 6,710 women mostly aged 40-49 at intermediate familial risk of breast cancer. One hundred and three cases of breast cancer were age-matched to one or two controls. Density was measured by semiautomated interactive thresholding. Absolute density, but not percent density, was a significant risk factor for breast cancer in this population after adjusting for area of nondense tissue (OR per 10 cm(2) = 1.07, 95% CI 1.00-1.15, p = 0.04). The effect was stronger in premenopausal women, who made up the majority of the study population. Absolute density remained a significant predictor of breast cancer risk after adjusting for age at menarche, age at first live birth, parity, past or present hormone replacement therapy, and the Tyrer-Cuzick 10-year relative risk estimate of breast cancer. Absolute density can improve breast cancer risk stratification and delineation of high-risk groups alongside the Tyrer-Cuzick 10-year relative risk estimate. © 2014 UICC.

  12. Effect of age on bone mineral density and micro architecture in the radius and tibia of horses: An Xtreme computed tomographic study

    Directory of Open Access Journals (Sweden)

    Schmidlin A

    2008-01-01

    Full Text Available Abstract Background The effect of age on the bone mineral density and microarchitecture of the equine radius and tibia was investigated. Fifty-six bones from 15 horses aged four to 21 years were used. There were nine geldings and six mares, and none of the horses had any disease influencing bone properties. Xtreme computed tomography was used to evaluate a 9-mm segment of the diaphysis and metaphysis of each bone. The following variables were determined: length of the bone, circumference and diameter in the frontal and sagittal planes in the middle of the bone. Diaphysis: total volume, bone volume, bone volume ratio, slice area, bone area, marrow area, cortical and marrow thickness, bone mineral density, polar moment of inertia of the cortex. Metaphysis: total area, bone area, cortical bone area, cortical thickness, bone mineral density, bone mineral density in the cortex, bone mineral density in the trabecular region, trabecular number, trabecular thickness, trabecular separation, polar moment of inertia of the metaphysis, polar moment of inertia of the cortex of the metaphysis. Results Bone density and microarchitecture were not affected by breed or gender. However, the microarchitecture varied with the age of the horse; the number of trabeculae decreased significantly and the distance between trabeculae increased significantly with increasing age. There were no significant differences between bones of the left and right limbs or between the radius and tibia. Conclusion The variables investigated did not differ between geldings and mares. However, there were age-related changes in the microstructure of the bones. Further experimental studies are necessary to determine whether these changes reduce bone strength. Age-related changes in the bones were seen and may explain the higher incidence of fractures and fissures in older horses.

  13. Effect of age on bone mineral density and micro architecture in the radius and tibia of horses: An Xtreme computed tomographic study

    Science.gov (United States)

    Fürst, A; Meier, D; Michel, S; Schmidlin, A; Held, L; Laib, A

    2008-01-01

    Background The effect of age on the bone mineral density and microarchitecture of the equine radius and tibia was investigated. Fifty-six bones from 15 horses aged four to 21 years were used. There were nine geldings and six mares, and none of the horses had any disease influencing bone properties. Xtreme computed tomography was used to evaluate a 9-mm segment of the diaphysis and metaphysis of each bone. The following variables were determined: length of the bone, circumference and diameter in the frontal and sagittal planes in the middle of the bone. Diaphysis: total volume, bone volume, bone volume ratio, slice area, bone area, marrow area, cortical and marrow thickness, bone mineral density, polar moment of inertia of the cortex. Metaphysis: total area, bone area, cortical bone area, cortical thickness, bone mineral density, bone mineral density in the cortex, bone mineral density in the trabecular region, trabecular number, trabecular thickness, trabecular separation, polar moment of inertia of the metaphysis, polar moment of inertia of the cortex of the metaphysis. Results Bone density and microarchitecture were not affected by breed or gender. However, the microarchitecture varied with the age of the horse; the number of trabeculae decreased significantly and the distance between trabeculae increased significantly with increasing age. There were no significant differences between bones of the left and right limbs or between the radius and tibia. Conclusion The variables investigated did not differ between geldings and mares. However, there were age-related changes in the microstructure of the bones. Further experimental studies are necessary to determine whether these changes reduce bone strength. Age-related changes in the bones were seen and may explain the higher incidence of fractures and fissures in older horses. PMID:18221526

  14. Effect of age on bone mineral density and micro architecture in the radius and tibia of horses: an Xtreme computed tomographic study.

    Science.gov (United States)

    Fürst, A; Meier, D; Michel, S; Schmidlin, A; Held, L; Laib, A

    2008-01-25

    The effect of age on the bone mineral density and microarchitecture of the equine radius and tibia was investigated. Fifty-six bones from 15 horses aged four to 21 years were used. There were nine geldings and six mares, and none of the horses had any disease influencing bone properties. Xtreme computed tomography was used to evaluate a 9-mm segment of the diaphysis and metaphysis of each bone. The following variables were determined: length of the bone, circumference and diameter in the frontal and sagittal planes in the middle of the bone.Diaphysis: total volume, bone volume, bone volume ratio, slice area, bone area, marrow area, cortical and marrow thickness, bone mineral density, polar moment of inertia of the cortex.Metaphysis: total area, bone area, cortical bone area, cortical thickness, bone mineral density, bone mineral density in the cortex, bone mineral density in the trabecular region, trabecular number, trabecular thickness, trabecular separation, polar moment of inertia of the metaphysis, polar moment of inertia of the cortex of the metaphysis. Bone density and microarchitecture were not affected by breed or gender. However, the microarchitecture varied with the age of the horse; the number of trabeculae decreased significantly and the distance between trabeculae increased significantly with increasing age. There were no significant differences between bones of the left and right limbs or between the radius and tibia. The variables investigated did not differ between geldings and mares. However, there were age-related changes in the microstructure of the bones. Further experimental studies are necessary to determine whether these changes reduce bone strength. Age-related changes in the bones were seen and may explain the higher incidence of fractures and fissures in older horses.

  15. Cytokine responses to the anti-schistosome vaccine candidate antigen glutathione-S-transferase vary with host age and are boosted by praziquantel treatment.

    Directory of Open Access Journals (Sweden)

    Claire D Bourke

    2014-05-01

    Full Text Available Improved helminth control is required to alleviate the global burden of schistosomiasis and schistosome-associated pathologies. Current control efforts rely on the anti-helminthic drug praziquantel (PZQ, which enhances immune responses to crude schistosome antigens but does not prevent re-infection. An anti-schistosome vaccine based on Schistosoma haematobium glutathione-S-transferase (GST is currently in Phase III clinical trials, but little is known about the immune responses directed against this antigen in humans naturally exposed to schistosomes or how these responses change following PZQ treatment.Blood samples from inhabitants of a Schistosoma haematobium-endemic area were incubated for 48 hours with or without GST before (n = 195 and six weeks after PZQ treatment (n = 107. Concentrations of cytokines associated with innate inflammatory (TNFα, IL-6, IL-8, type 1 (Th1; IFNγ, IL-2, IL-12p70, type 2 (IL-4, IL-5, IL-13, type 17 (IL-17A, IL-21, IL-23p19 and regulatory (IL-10 responses were quantified in culture supernatants via enzyme-linked immunosorbent assay (ELISA. Factor analysis and multidimensional scaling were used to analyse multiple cytokines simultaneously.A combination of GST-specific type 2 (IL-5 and IL-13 and regulatory (IL-10 cytokines was significantly lower in 10-12 year olds, the age group at which S. haematobium infection intensity and prevalence peak, than in 4-9 or 13+ year olds. Following PZQ treatment there was an increase in the number of participants producing detectable levels of GST-specific cytokines (TNFα, IL-6, IL-8, IFNγ, IL-12p70, IL-13 and IL-23p19 and also a shift in the GST-specific cytokine response towards a more pro-inflammatory phenotype than that observed before treatment. Participant age and pre-treatment infection status significantly influenced post-treatment cytokine profiles.In areas where schistosomiasis is endemic host age, schistosome infection status and PZQ treatment affect the

  16. Proximal Femur Volumetric Bone Mineral Density and Mortality: 13 Years of Follow-Up of the AGES-Reykjavik Study.

    Science.gov (United States)

    Marques, Elisa A; Elbejjani, Martine; Gudnason, Vilmundur; Sigurdsson, Gunnar; Lang, Thomas; Sigurdsson, Sigurdur; Aspelund, Thor; Meirelles, Osorio; Siggeirsdottir, Kristin; Launer, Lenore; Eiriksdottir, Gudny; Harris, Tamara B

    2017-06-01

    Bone mineral density (BMD) has been linked to mortality, but little is known about the independent contribution of each endosteal bone compartment and also the rate of bone loss to risk of mortality. We examined the relationships between (1) baseline trabecular and cortical volumetric BMD (vBMD) at the proximal femur, and (2) the rate of trabecular and cortical bone loss and all-cause mortality in older adults from the AGES-Reykjavik study. The analysis of trabecular and cortical vBMD and mortality was based on the baseline cohort of 4654 participants (aged ≥66 years) with a median follow-up of 9.4 years; the association between rate of bone loss and mortality was based on 2653 participants with bone loss data (median follow-up of 5.6 years). Analyses employed multivariable Cox-proportional models to estimate hazard ratios (HRs) with time-varying fracture status; trabecular and cortical variables were included together in all models. Adjusted for important confounders, Cox models showed that participants in the lowest quartile of trabecular vBMD had an increased risk of mortality compared to participants in other quartiles (HR = 1.12; 95% confidence interval (CI), 1.01 to 1.25); baseline cortical vBMD was not related to mortality (HR = 1.08; 95% CI, 0.97 to 1.20). After adjustment for time-dependent fracture status, results were attenuated and not statistically significant. A faster loss (quartile 1 versus quartiles 2-4) in both trabecular and cortical bone was associated with higher mortality risk (HR = 1.37 and 1.33, respectively); these associations were independent of major potential confounders including time-dependent incident fractures (HR = 1.32 and 1.34, respectively). Overall, data suggest that faster bone losses over time in both the trabecular and cortical bone compartments are associated with mortality risk and that measurements of change in bone health may be more informative than single-point measurements in explaining mortality

  17. Managers’ perspectives: practical experience and challenges associated with variable-density operations and uneven-aged management

    Science.gov (United States)

    Kurtis E. Steele

    2013-01-01

    Variable-density thinning has received a lot of public attention in recent years and has subsequently become standard language in most of the Willamette National Forest’s timber management projects. Many techniques have been tried, with varying on-the-ground successes. To accomplish variable-density thinning, the McKenzie River Ranger District currently uses...

  18. The association of bone mineral density measures with incident cardiovascular disease in older men and women: the Health, Aging, and Body Composition Study

    NARCIS (Netherlands)

    Farhat, G.N.; Newman, A.B.; Sutton-Tyrell, K.; Matthews, K.A.; Boudreau, R.; Schwartz, A.; Harris, T.B.; Tylavsky, F.A.; Visser, M.; Cauley, J.A.

    2007-01-01

    Summary: The associations of volumetric and areal bone mineral density (BMD) measures with incident cardiovascular disease (CVD) were studied in a biracial cohort of 2,310 older adults. BMD measures were inversely related to CVD in women and white men, independent of age and shared risk factors for

  19. Bone mineral density at distal forearm in men over 40 years of age in Mae Chaem district, Chiang Mai Province, Thailand: a pilot study.

    Science.gov (United States)

    Tungjai, Montree; Kaewjaeng, Siriprapa; Jumpee, Chayanit; Sriburee, Sompong; Hongsriti, Pongsiri; Tapanya, Monruedee; Maghanemi, Utumma; Ratanasthien, Kwanchai; Kothan, Suchart

    2017-09-01

    To study the prevalence of bone mineral density (BMD) and osteoporosis in the distal forearm among Thai men over 40 years of age in Mae Chaem District, Chiang Mai Province, Thailand. The subjects in this study were 194 Thai men, aged between 40 and 87 years who resided in Mae Chaem District, Chiang Mai Province, Thailand. Self-administered questionnaires were used for receiving the demographic characteristics information. BMD was measured by peripheral dual energy X-ray absorptiometry at the nondominant distal forearm in all men. The BMD was highest in the age-group 40-49 years and lowest in the age-group 70-87 years. The average T-score at the distal forearm was also highest in the age-group 40-49 years and lowest in the age-group 70-87 years. The BMD decreased as a function of age-group (p  .05). The percentage of osteopenia and osteoporosis are increased as a function of age-group in, while decreased in that of normal bone density. We found the prevalence of osteoporosis in men who resided in Mae Chaem District, Chiang Mai Province, Thailand.

  20. Density dependent interactions between VA mycorrhizal fungi and even-aged seedlings of two perennial Fabaceae species.

    Science.gov (United States)

    Allsopp, N; Stock, W D

    1992-08-01

    The interaction of density and mycorrhizal effects on the growth, mineral nutrition and size distribution of seedlings of two perennial members of the Fabaceae was investigated in pot culture. Seedlings of Otholobium hirtum and Aspalathus linearis were grown at densities of 1, 4, 8 and 16 plants per 13-cm pot with or without vesicular-arbuscular (VA) mycorrhizal inoculum for 120 days. Plant mass, relative growth rates, height and leaf number all decreased with increasing plant density. This was ascribed to the decreasing availability of phosphorus per plant as density increased. O. hirtum was highly dependent on mycorrhizas for P uptake but both mycorrhizal and non-mycorrhizal A. linearis seedlings were able to extract soil P with equal ease. Plant size distribution as measured by the coefficient of variation (CV) of shoot mass was greater at higher densities. CVs of mycorrhizal O. hirtum plants were higher than those of non-mycorrhizal plants. CVs of the facultatively mycorrhizal A. linearis were similar for both mycorrhizal and non-mycorrhizal plants. Higher CVs are attributed to resource preemption by larger individuals. Individuals in populations with high CVs will probably survive stress which would result in the extinction of populations with low CVs. Mass of mycorrhizal plants of both species decreased more rapidly with increasing density than did non-mycorrhizal plant mass. It is concluded that the cost of being mycorrhizal increases as plant density increases, while the benefit decreases. The results suggest that mycorrhizas will influence density-dependent population processes of faculative and obligate mycorrhizal species.

  1. Age and sex differences in oxytocin and vasopressin V1a receptor binding densities in the rat brain: focus on the social decision-making network.

    Science.gov (United States)

    Smith, Caroline J W; Poehlmann, Max L; Li, Sara; Ratnaseelan, Aarane M; Bredewold, Remco; Veenema, Alexa H

    2017-03-01

    Oxytocin (OT) and vasopressin (AVP) regulate various social behaviors via activation of the OT receptor (OTR) and the AVP V1a receptor (V1aR) in the brain. Social behavior often differs across development and between the sexes, yet our understanding of age and sex differences in brain OTR and V1aR binding remains incomplete. Here, we provide an extensive analysis of OTR and V1aR binding density throughout the brain in juvenile and adult male and female rats, with a focus on regions within the social decision-making network. OTR and V1aR binding density were higher in juveniles than in adults in regions associated with reward and socio-spatial memory and higher in adults than in juveniles in key regions of the social decision-making network and in cortical regions. We discuss possible implications of these shifts in OTR and V1aR binding density for the age-specific regulation of social behavior. Furthermore, sex differences in OTR and V1aR binding density were less numerous than age differences. The direction of these sex differences was region-specific for OTR but consistently higher in females than in males for V1aR. Finally, almost all sex differences in OTR and V1aR binding density were already present in juveniles and occurred in regions with denser binding in adults compared to juveniles. Possible implications of these sex differences for the sex-specific regulation of behavior, as well potential underlying mechanisms, are discussed. Overall, these findings provide an important framework for testing age- and sex-specific roles of OTR and V1aR in the regulation of social behavior.

  2. Creating a normative database of age-specific 3D geometrical data, bone density, and bone thickness of the developing skull: a pilot study.

    Science.gov (United States)

    Delye, Hans; Clijmans, Tim; Mommaerts, Maurice Yves; Sloten, Jos Vnder; Goffin, Jan

    2015-12-01

    Finite element models (FEMs) of the head are used to study the biomechanics of traumatic brain injury and depend heavily on the use of accurate material properties and head geometry. Any FEM aimed at investigating traumatic head injury in children should therefore use age-specific dimensions of the head, as well as age-specific material properties of the different tissues. In this study, the authors built a database of age-corrected skull geometry, skull thickness, and bone density of the developing skull to aid in the development of an age-specific FEM of a child's head. Such a database, containing age-corrected normative skull geometry data, can also be used for preoperative surgical planning and postoperative long-term follow-up of craniosynostosis surgery results. Computed tomography data were processed for 187 patients (age range 0-20 years old). A 3D surface model was calculated from segmented skull surfaces. Skull models, reference points, and sutures were processed into a MATLAB-supported database. This process included automatic calculation of 2D measurements as well as 3D measurements: length of the coronal suture, length of the lambdoid suture, and the 3D anterior-posterior length, defined as the sum of the metopic and sagittal suture. Skull thickness and skull bone density calculations were included. Cephalic length, cephalic width, intercoronal distance, lateral orbital distance, intertemporal distance, and 3D measurements were obtained, confirming the well-established general growth pattern of the skull. Skull thickness increases rapidly in the first year of life, slowing down during the second year of life, while skull density increases with a fast but steady pace during the first 3 years of life. Both skull thickness and density continue to increase up to adulthood. This is the first report of normative data on 2D and 3D measurements, skull bone thickness, and skull bone density for children aged 0-20 years. This database can help build an age

  3. Effects of reduced dietary energy and amino acid density on Pectoralis major myopathies in broiler chickens at 36 and 49 days of age1.

    Science.gov (United States)

    Meloche, K J; Fancher, B I; Emmerson, D A; Bilgili, S F; Dozier, W A

    2018-05-01

    Two experiments (Exp) were conducted to determine if reductions in the incidence and severity of wooden breast (WB) and white striping (WS) may be obtained by reducing dietary nutrient density. In each Exp, Yield Plus × Ross 708 male broiler chicks were placed into 63 pens (22 birds/pen). All birds received an identical prestarter diet until 7 d of age, after which time each pen was randomly assigned to 1 of the following 7 dietary treatments (TRT) for the starter (8 to 14 d), grower (15 to 24 d), finisher 1 (Exp 1: 26 to 35 d; Exp 2: 26 to 42 d), and withdrawal (Exp 2: 43 to 48 d) phases: 1) 100% of primary breeder recommendations for digestible amino acid and metabolizable energy density throughout Exp; 2) 95% of TRT 1 until 14 d of age, then as TRT 1; 3) 95% of TRT 1 until 24 d of age, then as TRT 1; 4) 95% of TRT 1 throughout Exp; 5) 90% of TRT 1 until 14 d of age, then as TRT 1; 6) 90% of TRT 1 until 24 d of age, then as TRT 1; 7) 90% of TRT 1 throughout Exp. At 36 d (Exp 1) and 49 d (Exp 2), 18 birds per pen were processed and evaluated for WS and WB. In Exp 1, reduced dietary density in the starter phase (TRT 2 and TRT 5) resulted in increased (P ≤ 0.05) incidences of severe WB (32.9% and 34.7%) relative to TRT 1 (18.2%). In Exp 2, broilers assigned to TRT 7 had reduced (P 36.5%; WS: 64.5%). In both Exp, plasma creatine kinase and lactate dehydrogenase increased (P ≤ 0.05) with increasing scores for WB and WS. Reducing dietary nutrient density from 8 to 14 d may exacerbate fillet myopathies in broilers reared to 35 d of age. Although reducing dietary energy and amino acid density to 90% of recommendations from 1 to 48 d reduced the severity of myopathies, these reductions occurred with compromises in live performance. Altogether, these results indicated that concurrent manipulation of dietary amino acid and energy density is not a viable practical solution for breast myopathies.

  4. Planting density and silvicultural intensity impacts on loblolly pine stand development in the western gulf coastal plain through age 8

    Science.gov (United States)

    Michael B. Kane; Dehai Zhao; John W. Rheney; Michael G. Messina; Mohd S. Rahman; Nicholas Chappell

    2012-01-01

    Commercial plantation growers need to know how planting density and cultural regime intensity affect loblolly pine plantation productivity, development and value to make sound management decisions. This knowledge is especially important given the diversity of traditional products, such as pulpwood, chip-n-saw, and sawtimber, and potential products, such as bioenergy...

  5. Ab initio and density functional theoretical design and screening of model crown ether based ligand (host) for extraction of lithium metal ion (guest): effect of donor and electronic induction.

    Science.gov (United States)

    Boda, Anil; Ali, Sk Musharaf; Rao, Hanmanth; Ghosh, Sandip K

    2012-08-01

    The structures, energetic and thermodynamic parameters of model crown ethers with different donor, cavity and electron donating/ withdrawing functional group have been determined with ab initio MP2 and density functional theory in gas and solvent phase. The calculated values of binding energy/ enthalpy for lithium ion complexation are marginally higher for hard donor based aza and oxa crown compared to soft donor based thia and phospha crown. The calculated values of binding enthalpy for lithium metal ion with 12C4 at MP2 level of theory is in good agreement with the available experimental result. The binding energy is altered due to the inductive effect imparted by the electron donating/ withdrawing group in crown ether, which is well correlated with the values of electron transfer. The role of entropy for extraction of hydrated lithium metal ion by different donor and functional group based ligand has been demonstrated. The HOMO-LUMO gap is decreased and dipole moment of the ligand is increased from gas phase to organic phase because of the dielectric constant of the solvent. The gas phase binding energy is reduced in solvent phase as the solvent molecules weaken the metal-ligand binding. The theoretical values of extraction energy for LiCl salt from aqueous solution in different organic solvent is validated by the experimental trend. The study presented here should contribute to the design of model host ligand and screening of solvent for metal ion recognition and thus can contribute in planning the experiments.

  6. Aging adult skull remains through radiological density estimates: A comparison of different computed tomography systems and the use of computer simulations to judge the accuracy of results.

    Science.gov (United States)

    Obert, Martin; Kubelt, Carolin; Schaaf, Thomas; Dassinger, Benjamin; Grams, Astrid; Gizewski, Elke R; Krombach, Gabriele A; Verhoff, Marcel A

    2013-05-10

    The objective of this article was to explore age-at-death estimates in forensic medicine, which were methodically based on age-dependent, radiologically defined bone-density (HC) decay and which were investigated with a standard clinical computed tomography (CT) system. Such density decay was formerly discovered with a high-resolution flat-panel CT in the skulls of adult females. The development of a standard CT methodology for age estimations--with thousands of installations--would have the advantage of being applicable everywhere, whereas only few flat-panel prototype CT systems are in use worldwide. A Multi-Slice CT scanner (MSCT) was used to obtain 22,773 images from 173 European human skulls (89 male, 84 female), taken from a population of patients from the Department of Neuroradiology at the University Hospital Giessen and Marburg during 2010 and 2011. An automated image analysis was carried out to evaluate HC of all images. The age dependence of HC was studied by correlation analysis. The prediction accuracy of age-at-death estimates was calculated. Computer simulations were carried out to explore the influence of noise on the accuracy of age predictions. Human skull HC values strongly scatter as a function of age for both sexes. Adult male skull bone-density remains constant during lifetime. Adult female HC decays during lifetime, as indicated by a correlation coefficient (CC) of -0.53. Prediction errors for age-at-death estimates for both of the used scanners are in the range of ±18 years at a 75% confidence interval (CI). Computer simulations indicate that this is the best that can be expected for such noisy data. Our results indicate that HC-decay is indeed present in adult females and that it can be demonstrated both by standard and by high-resolution CT methods, applied to different subject groups of an identical population. The weak correlation between HC and age found by both CT methods only enables a method to estimate age-at-death with limited

  7. Effect of age-dependent bone electron density on the calculated dose distribution from kilovoltage and megavoltage photon and electron radiotherapy in paediatric MRI-only treatment planning.

    Science.gov (United States)

    Zeinali-Rafsanjani, B; Faghihi, R; Mosleh-Shirazi, M A; Saeedi-Moghadam, M; Jalli, R; Sina, S

    2018-01-01

    MRI-only treatment planning (TP) can be advantageous in paediatric radiotherapy. However, electron density extraction is necessary for dose calculation. Normally, after bone segmentation, a bulk density is assigned. However, the variation of bone bulk density in patients makes the creation of pseudo CTs challenging. This study aims to assess the effects of bone density variations in children on radiation attenuation and dose calculation for MRI-only TP. Bone contents of <15-year-old children were calculated, and substituted in the Oak Ridge National Laboratory paediatric phantoms. The percentage depth dose and beam profile of 150 kVp and 6 MV photon and 6 MeV electron beams were then calculated using Xcom, MCNPX (Monte Carlo N-particle version X) and ORLN phantoms. Using 150 kVp X-rays, the difference in attenuation coefficient was almost 5% between an 11-year-old child and a newborn, and ~8% between an adult and a newborn. With megavoltage radiation, the differences were smaller but still important. For an 18 MV photon beam, the difference of radiation attenuation between an 11-year-old child and a newborn was 4% and ~7.4% between an adult and a newborn. For 6 MeV electrons, dose differences were observed up to the 2 cm depth. The percentage depth dose difference between 1 and 10-year-olds was 18.5%, and between 10 and 15-year-olds was 24%. The results suggest that for MRI-only TP of photon- or electron-beam radiotherapy, the bone densities of each age group should be defined separately for accurate dose calculation. Advances in knowledge: This study highlights the need for more age-specific determination of bone electron density for accurate dose calculations in paediatric MRI-only radiotherapy TP.

  8. Comparative analysis of compressive strength tests at age of 28 and 90 days and density of products using chemical additives in cementing radioactive waste

    International Nuclear Information System (INIS)

    Vieira, Vanessa Mota; Tello, Cledola Cassia Oliveira de

    2013-01-01

    In this research it has been studied the effects of chemical additives (admixtures) in the cementation process of radioactive wastes, which are used to improve the properties of waste cementation process, both of the paste and of the solidified product. However there are a large variety of these materials that are frequently changed or taken out of the market, then it is essential to know the commercially available materials and their effects. The tests were carried out with a solution simulating the evaporator concentrate waste coming from PWR nuclear reactors. It was cemented using two formulations, A and B, incorporating higher or lower amount of waste, respectively. It was added chemical admixtures from two manufacturers (S and H), which were: accelerators, set retarders and superplasticizers. The experiments were organized by a factorial design 2 3 . The measured parameters were the viscosity, the setting time, the paste and product density and the compressive strength. In this study we performed comparative analyzes of the results of compressive strength at age of 28 and 90 days and between the densities of the samples at the same ages.The compressive strength test at age of 28 days is considered a parameter essential issues related to security handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented product, but presented lower values density products. (author)

  9. Age

    Science.gov (United States)

    ... adults? How can you reduce anesthesia risks in older patients? Age Age may bring wisdom but it also brings ... Ask your physician to conduct a pre-surgery cognitive test — an assessment of your mental function. The physician can use the results as a ...

  10. Properties of high-density binary mixtures and the age of the Universe from white dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Berro, E.; Hernanz, M.; Isern, J.; Mochkovitch, R.

    1988-06-16

    The luminosity of white dwarf stars can be attributed to the cooling process of their degenerate cores. The simple relationship existing between their luminosity and their age, together with the lack of white dwarfs fainter than log (L/L solar mass) approx -4.5, provides a method of measuring the age of the disk and consequently that of the Universe. Values of the age of the galactic disk and Universe depend on the assumption that completely ionized carbon and oxygen are miscible in solid phase. It is possible, however, that completely ionized carbon and oxygen separate during the process of crystallization. Here, we attempt to show that a galactic disk age of 15 Gyr cannot be excluded by the white dwarf observations if carbon and oxygen are immiscible in solid phase.

  11. Restabilization of the aging resistance of compatibilized blends of pre-aged low density polyethylene and high-impact polystyrene (LDPE/HIPS)

    Czech Academy of Sciences Publication Activity Database

    Michálková, Danuše; Pospíšil, Jan; Fortelný, Ivan; Hromádková, Jiřina; Lednický, František; Schmidt, Pavel; Kruliš, Zdeněk

    2009-01-01

    Roč. 94, č. 9 (2009), s. 1486-1493 ISSN 0141-3910 R&D Projects: GA MŠk 2B06097 Institutional research plan: CEZ:AV0Z40500505 Keywords : blends with pre-aged LDPE * upgrading of impact strength * thermal restabilization Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.154, year: 2009

  12. Population age and initial density in a patchy environment affect the occurrence of abrupt transitions in a birth-and-death model of Taylor's law

    Science.gov (United States)

    Jiang, Jiang; DeAngelis, Donald L.; Zhang, B.; Cohen, J.E.

    2014-01-01

    Taylor's power law describes an empirical relationship between the mean and variance of population densities in field data, in which the variance varies as a power, b, of the mean. Most studies report values of b varying between 1 and 2. However, Cohen (2014a) showed recently that smooth changes in environmental conditions in a model can lead to an abrupt, infinite change in b. To understand what factors can influence the occurrence of an abrupt change in b, we used both mathematical analysis and Monte Carlo samples from a model in which populations of the same species settled on patches, and each population followed independently a stochastic linear birth-and-death process. We investigated how the power relationship responds to a smooth change of population growth rate, under different sampling strategies, initial population density, and population age. We showed analytically that, if the initial populations differ only in density, and samples are taken from all patches after the same time period following a major invasion event, Taylor's law holds with exponent b=1, regardless of the population growth rate. If samples are taken at different times from patches that have the same initial population densities, we calculate an abrupt shift of b, as predicted by Cohen (2014a). The loss of linearity between log variance and log mean is a leading indicator of the abrupt shift. If both initial population densities and population ages vary among patches, estimates of b lie between 1 and 2, as in most empirical studies. But the value of b declines to ~1 as the system approaches a critical point. Our results can inform empirical studies that might be designed to demonstrate an abrupt shift in Taylor's law.

  13. Aging

    International Nuclear Information System (INIS)

    Sasaki, Hideo; Kodama, Kazunori; Yamada, Michiko

    1991-01-01

    The hypothesis that exposure to ionizing radiation accelerates the aging process has been actively investigated at ABCC-RERF since 1958, when longitudinal cohort studies of the Adult Health Study (AHS) and the Life Span Study (LSS) were initiated. In their 1975 overall review of aging studies related to the atomic bomb (A-bomb) survivors, Finch and Beebe concluded that while most studies had shown no correlation between aging and radiation exposure, they had not involved the large numbers of subjects required to provide strong evidence for or against the hypothesis. Extending LSS mortality data up to 1978 did not alter the earlier conclusion that any observed life-shortening was associated primarily with cancer induction rather than with any nonspecific cause. The results of aging studies conducted during the intervening 15 years using data from the same populations are reviewed in the present paper. Using clinical, epidemiological, and laboratory techniques, a broad spectrum of aging parameters have been studied, such as postmortem morphological changes, tests of functional capacity, physical tests and measurements, laboratory tests, tissue changes, and morbidity. With respect to the aging process, the overall results have not been consistent and are generally thought to show no relation to radiation exposure. Although some preliminary results suggest a possible radiation-induced increase in atherosclerotic diseases and acceleration of aging in the T-cell-related immune system, further study is necessary to confirm these findings. In the future, applying the latest gerontological study techniques to data collected from subjects exposed 45 years ago to A-bomb radiation at relatively young ages will present a new body of data relevant to the study of late radiation effects. (author) 103 refs

  14. Aging

    International Nuclear Information System (INIS)

    Finch, S.C.; Beebe, G.W.

    1975-01-01

    The hypothesis that ionizing radiation accelerates natural aging has been under investigation at the Atomic Bomb Casualty Commission since 1959. Postmortem observations of morphologic and chemical changes, tests of functional capacity, physical tests and measurements, clinical laboratory tests, tissue changes, morbidity, and mortality have all been examined by ABCC investigators interested in this hypothesis. These studies have been beset with conceptual difficulties centered on the definition and measurement of aging. An empirical approach early led to the calculation of an index of physiologic age as a linear combination of age-related tests of various organ systems. Most studies have been negative but have not involved the large numbers that might be required to provide strong evidence for or against the hypothesis. Mortality, however, has been examined on the basis of a large sample and over the period 1950-1972 had provided no support for the hypothesis of radiation-accelerated aging. Ionizing radiation dose, of course shorten human life, but its life-shortening effect appears to be the result of specific radiation-induced disease, especially neoplasms. The hypothesis is now much less attractive than it was 10-20 years ago but still has some value in stimulating research on aging. The experience of the A-bomb survivors provides an unusual opportunity for a definitive test of the hypothesis. (auth.)

  15. Effects of self-reported age at nonsurgical menopause on time to first fracture and bone mineral density in the Women's Health Initiative Observational Study.

    Science.gov (United States)

    Sullivan, Shannon D; Lehman, Amy; Thomas, Fridtjof; Johnson, Karen C; Jackson, Rebecca; Wactawski-Wende, Jean; Ko, Marcia; Chen, Zhao; Curb, J David; Howard, Barbara V

    2015-10-01

    Menopause is a risk factor for fracture; thus, menopause age may affect bone mass and fracture rates. We compared bone mineral density (BMD) and fracture rates among healthy postmenopausal women with varying ages at self-reported nonsurgical menopause. We compared hazard ratios for fractures and differences in BMD among 21,711 postmenopausal women from the Women's Health Initiative Observational Study cohort who had no prior hysterectomy, oophorectomy, or hormone therapy and had varying self-reported ages at menopause (menopause age groups. After multivariable adjustments for known risk factors for fracture, women who underwent menopause before age 40 years had a higher fracture risk at any site compared with women who underwent menopause at age 50 years or older (hazard ratio, 1.21; 95% CI, 1.02 to 1.44; P = 0.03). In a subset with BMD measurements (n = 1,351), whole-body BMD was lower in women who reported menopause before age 40 years than in women who reported menopause at ages 40 to 49 years (estimated difference, -0.034 g/cm; 95% CI, -0.07 to -0.004; P = 0.03) and women who reported menopause at age 50 years or older (estimated difference, -0.05 g/cm; 95% CI, -0.08 to -0.02; P menopause before age 40 years than in women who underwent menopause at age 50 years or older (estimated difference, -0.05 g/cm; 95% CI, -0.08 to -0.01; P = 0.01), and total spine BMD was lower in women who underwent menopause before age 40 years than in women who underwent menopause at age 50 years or older (estimated difference, -0.11 g/cm; 95% CI, -0.16 to -0.06; P menopause at ages 40 to 49 years (estimated difference, -0.09 g/cm; 95% CI, -0.15 to -0.04; P menopause may be a risk factor contributing to decreased BMD and increased fracture risk in healthy postmenopausal women. Our data suggest that menopause age should be taken into consideration, along with other osteoporotic risk factors, when estimating fracture risk in postmenopausal women.

  16. Age-dependence of power spectral density and fractal dimension of bone mineralized matrix in atomic force microscope topography images: potential correlates of bone tissue age and bone fragility in female femoral neck trabeculae.

    Science.gov (United States)

    Milovanovic, Petar; Djuric, Marija; Rakocevic, Zlatko

    2012-11-01

    There is an increasing interest in bone nano-structure, the ultimate goal being to reveal the basis of age-related bone fragility. In this study, power spectral density (PSD) data and fractal dimensions of the mineralized bone matrix were extracted from atomic force microscope topography images of the femoral neck trabeculae. The aim was to evaluate age-dependent differences in the mineralized matrix of human bone and to consider whether these advanced nano-descriptors might be linked to decreased bone remodeling observed by some authors and age-related decline in bone mechanical competence. The investigated bone specimens belonged to a group of young adult women (n = 5, age: 20-40 years) and a group of elderly women (n = 5, age: 70-95 years) without bone diseases. PSD graphs showed the roughness density distribution in relation to spatial frequency. In all cases, there was a fairly linear decrease in magnitude of the power spectra with increasing spatial frequencies. The PSD slope was steeper in elderly individuals (-2.374 vs. -2.066), suggesting the dominance of larger surface morphological features. Fractal dimension of the mineralized bone matrix showed a significant negative trend with advanced age, declining from 2.467 in young individuals to 2.313 in the elderly (r = 0.65, P = 0.04). Higher fractal dimension in young women reflects domination of smaller mineral grains, which is compatible with the more freshly remodeled structure. In contrast, the surface patterns in elderly individuals were indicative of older tissue age. Lower roughness and reduced structural complexity (decreased fractal dimension) of the interfibrillar bone matrix in the elderly suggest a decline in bone toughness, which explains why aged bone is more brittle and prone to fractures. © 2012 The Authors Journal of Anatomy © 2012 Anatomical Society.

  17. LAST II: Differential temporal responses of macular pigment optical density in patients with atrophic age-related macular degeneration to dietary supplementation with xanthophylls.

    Science.gov (United States)

    Richer, Stuart; Devenport, Jenny; Lang, John C

    2007-05-01

    Age-related macular degeneration (ARMD) is the leading cause of vision loss in aging Western societies. The objective of the Lutein Antioxidant Supplementation Trial (LAST) was to determine whether specific dietary interventions increased macular pigment optical density (MPOD) and visual function in patients with atrophic ARMD. The current objective of LAST II is to discern those specific characteristics that increase MPOD, i.e., that might differentiate a responder from a nonresponder. The LAST study was a prospective, 12-month, randomized, double-masked, placebo-controlled trial conducted at an urban midwestern Veterans Administation Hospital from August 1999 to May 2001. Ninety patients with atrophic ARMD entered the study and were assigned randomly to 1 of 3 groups. Patients in group 1 received 10 mg lutein; in group 2, 10 mg lutein in combination with vitamins, minerals, and antioxidants; and in group 3, maltodextrin placebo. Changes in macular MPOD over time were evaluated. Characteristics potentially influencing MPOD included age, weight (body mass index), initial baseline values of macular pigment, and combining xanthophylls with other nutrients. MPOD increased with supplementation and declined slightly without supplementation (regression slopes not equal to zero in supplemented groups, P < 0.02). The highest increases in MPOD over time occurred in patients with lower baseline values of MPOD. Statistically significant increases in MPOD density were observed in the lutein group for patients with baseline MPOD density units and up to 0.2 optical density units in the lutein plus antioxidant group. Further analysis found that none of the subjects' eyes in the lowest quartile of baseline MPOD were in the lowest quartile for change in MPOD. Noteworthy is the observation that those individuals with lowest MPOD, and in greatest need of supplementation, were also most likely to benefit from either the lutein or the lutein plus antioxidant

  18. Association between leukocyte telomere length and bone mineral density in women 25-93 years of age

    DEFF Research Database (Denmark)

    Nielsen, Barbara Rubek; Linneberg, Allan; Bendix, Laila

    2015-01-01

    whether there is an association of LTL with BMD and to determine whether this possible association is independent of age. The BMDs of the lumbar spine (LS), femoral neck (FN) and total hip (TH) were evaluated in 460 women using DXA. LTL was analyzed using quantitative polymerase chain reaction. The women...... and 95% confidence interval (CI): -0.003 (-0.005; -0.002)); and between BMI adjusted age and logarithmic transformed BMD. Estimates and 95% CI were as follows: LS: -0.13 (-0.26; -0.01); right TH: -0.44 (-0.53; -0.34); left TH: -0.38 (-0.48; -0.28); right FN: -0.57 (-0.67; -0.46) and left FN: -0.51 (-0.......62; -0.40). There were no statistically significant associations between BMD and LTL (both logarithmically transformed) with or without age adjustments. The age-adjusted estimates and CI were as follows: LS: -0.10 (-0.71; 0.52); right TH: -0.13 (-0.66; 0.41); left TH: -0.13 (-0.67; 0.42); right FN: -0...

  19. Age-Related Shifts in the Density and Distribution of Genetic Marker Water Quality Indicators in Cow and Calf Feces

    Science.gov (United States)

    Recent studies have shown that different adult bovine animal feeding practices dramatically influence fecal indicator bacteria shedding, however very little is known about juvenile milk-fed calves. Calves (≤ 6 months of age) make up about 16% of the current bovine population in ...

  20. Clinical relevance of radiologic examination of the skeleton and bone density measurements in osteoporosis of old age

    International Nuclear Information System (INIS)

    Kuester, W.; Seidl, G.; Linkesch, W.; Kotscher, E.; Kovarik, J.; Willvonseder, R.; Kovarik, J.; Willvonseder, R.; Dorda, W.

    1981-01-01

    For the diagnosis of primary osteoporosis, various semiquantitative radiologic methods were compared in 149 unselected patients, aged over 50 years. Crush fracture syndrome (CFS), lumbar spine index (LSI), and Singh Index (SI) were assessed by three radiologists and after reevaluation, the intra- and interobserver errors were calculated. The reliability of the subjective grading was improved by joint and repeated reading of the radiographs. Additionally, the peripheral trabecular bone content was measured by photonabsorptiondensitometry (PAD). To test the value of the various semiquantitative methods. LSI, Si, and PAD have been compared with sex-matching before and after separation into age in decades in CFS-positive and CFS-negative patients. In an attempt to differentiate osteoporotics and non-osteoporotics by CFS, our results indicate that CFS-positive and CFS-negative males cannot be separated by LSI, Si, and PAD, whereas in females these methods can discriminate irrespective of the age in decades. However, in age related groups, only SI can discriminate significantly between CFS-positive and CFS-negative females. Correlation of the semiquantitative methods, regardless of the diagnosis of a CFS, revealed a significant correlation-between SI and PAD, but no correlation between LSI and SI, and LSI and PAD, respectively. (orig.)

  1. Combined Effects of Spaceflight and Age in Astronauts as Assessed by Areal Bone Mineral Density [BMD] and Trabecular Bone Score

    Science.gov (United States)

    Sibonga, Jean D.; Spector, Elizabeth R.; Ploutz-Snyder, R.; Evans, H. J.; King, L.; Watts, N. B.; Hans, D.; Smith, S. A.

    2013-01-01

    Spaceflight is a potential risk factor for secondary osteoporosis in astronauts. Although lumbar spine (LS) BMD declines rapidly, more than expected for age, there have been no fragility fractures in astronauts that can clearly be attributed to spaceflight. Recently, astronauts have been returning from 6-month spaceflights with absolute BMD still above young adult mean BMD. In spite of these BMD measurements, we project that the rapid loss in bone mass over long-duration spaceflight affects the bone microarchitecture of the LS which might predispose astronauts to premature vertebral fractures. Thus, we evaluated TBS, a novel texture index correlated with vertebral bone microarchitecture, as a means of monitoring changes to bone microarchitecture in astronauts as they age. We previously reported that TBS detects an effect of spaceflight (6-month duration), independent of BMD, in 51 astronauts (47+/-4 y) (Smith et al, J Clin Densitometry 2014). Hence, TBS was evaluated in serial DXA scans (Hologic Discovery W) conducted triennially in all active and retired astronauts and more frequently (before spaceflight, after spaceflight and until recovery) in the subset of astronauts flying 4-6- month missions. We used non-linear models to describe trends in observations (BMD or TBS) plotted as a function of astronaut age. We fitted 1175 observations of 311 astronauts, pre-flight and then postflight starting 3 years after landing or after astronaut's BMD for LS was restored to within 2% of preflight BMD. Observations were then grouped and defined as follows: 1) LD: after exposure to at least one long-duration spaceflight > 100 days and 2) SD: before LD and after exposure to at least one short-duration spaceflight < 30 days. Data from males and females were analyzed separately. Models of SD observations revealed that TBS and BMD had similar curvilinear declines with age for both male and female astronauts. However, models of LD observations showed TBS declining with age while

  2. Smog chamber study on aging of combustion soot in isoprene/SO2/NOx system: Changes of mass, size, effective density, morphology and mixing state

    Science.gov (United States)

    Li, Kangwei; Chen, Linghong; Han, Ke; Lv, Biao; Bao, Kaiji; Wu, Xuecheng; Gao, Xiang; Cen, Kefa

    2017-02-01

    Atmospheric soot aging process is always accompanied by secondary particle formation, which is a comprehensive environmental issue that deserves great attention. On one hand, aging of primary soot could change its own physicochemical properties; on the other hand, complex air pollution caused by pollutant emission from various sources (e.g., vehicle exhausts, coal-fired flue gases and biogenic VOCs emission) may contribute to secondary particle formation onto primary particle surface. In this study, aging of combustion soot in isoprene/SO2/NOx system was investigated under controlled laboratory conditions in several smog chamber experiments. During the evolution of soot, several physical properties such as mass, size, effective density, morphology and mixing state were determined simultaneously by an integrated aerosol analytical system of Scanning Mobility Particle Sizer (SMPS), Differential Mobility Analyzer-Aerosol Particle Mass Analyzer-Condensation Particle Counter (DMA-APM-CPC) and Transmission Electron Microscopy coupled with Energy-dispersive X-ray Spectrometry (TEM/EDX) techniques. Here, based on the experimental results of soot aging under different gas-phase composition and relative humidity (RH), we firstly proposed possible aging pathways of soot in isoprene/SO2/NOx system. A synergetic effect was speculated to exist between SO2 and isoprene on soot aging process, which led to more secondary particle formation. At the same time, TEM/EDX analysis showed that a competitive mechanism between H2SO4(g) and isoprene oxidation vapor may exist: H2SO4(g) firstly condensed onto fresh soot, then an acceleration of isoprene oxidation products formed onto H2SO4 pre-coated soot. In isoprene/SO2/NOx system, high RH conditions could contribute to soot aging and new particle formation. The changes of effective density and dynamic shape factor of soot also indicated that high RH conditions could accelerate soot aging process, and led chain-like soot into more spherical

  3. Divergent Significance of Bone Mineral Density Changes in Aging Depending on Sites and Sex Revealed through Separate Analyses of Bone Mineral Content and Area

    Directory of Open Access Journals (Sweden)

    Yasumoto Matsui

    2012-01-01

    Full Text Available Bone mineral density (aBMD is equivalent to bone mineral content (BMC divided by area. We rechecked the significance of aBMD changes in aging by examining BMC and area separately. Subjects were 1167 community-dwelling Japanese men and women, aged 40–79 years. ABMDs of femoral neck and lumbar spine were assessed by DXA twice, at 6-year intervals. The change rates of BMC and area, as well as aBMD, were calculated and described separately by the age stratum and by sex. In the femoral neck region, aBMDs were significantly decreased in all age strata by an increase in area as well as BMC loss in the same pattern in both sexes. In the lumbar spine region, aBMDs decreased until the age of 60 in women, caused by the significant BMC decrease accompanying the small area change. Very differently in men, aBMDs increased after their 50s due to BMC increase, accompanied by an area increase. Separate analyses of BMC and area change revealed that the significance of aBMD changes in aging was very divergent among sites and between sexes. This may explain in part the dissociation of aBMD change and bone strength, suggesting that we should be more cautious when interpreting the meaning of aBMD change.

  4. Parasite transmission in social interacting hosts: Monogenean epidemics in guppies

    Science.gov (United States)

    Johnson, Mirelle B.; Lafferty, Kevin D.; van Oosterhout, Cock; Cable, Joanne

    2011-01-01

    Background Infection incidence increases with the average number of contacts between susceptible and infected individuals. Contact rates are normally assumed to increase linearly with host density. However, social species seek out each other at low density and saturate their contact rates at high densities. Although predicting epidemic behaviour requires knowing how contact rates scale with host density, few empirical studies have investigated the effect of host density. Also, most theory assumes each host has an equal probability of transmitting parasites, even though individual parasite load and infection duration can vary. To our knowledge, the relative importance of characteristics of the primary infected host vs. the susceptible population has never been tested experimentally. Methodology/Principal Findings Here, we examine epidemics using a common ectoparasite, Gyrodactylus turnbulli infecting its guppy host (Poecilia reticulata). Hosts were maintained at different densities (3, 6, 12 and 24 fish in 40 L aquaria), and we monitored gyrodactylids both at a population and individual host level. Although parasite population size increased with host density, the probability of an epidemic did not. Epidemics were more likely when the primary infected fish had a high mean intensity and duration of infection. Epidemics only occurred if the primary infected host experienced more than 23 worm days. Female guppies contracted infections sooner than males, probably because females have a higher propensity for shoaling. Conclusions/Significance These findings suggest that in social hosts like guppies, the frequency of social contact largely governs disease epidemics independent of host density.

  5. SIDE TO SIDE DIFFERENCES BETWEEN DOMINANT AND NON-DOMINANT ARM'S BONE DENSITY AND ISOMETRIC HANDGRIP STRENGTH IN MALES AND FEMALES AGED 40-65 YEARS OLD.

    Science.gov (United States)

    Krasniqi, Ermira; Koni, Mynyr; Kabashi, Antigona; Bahtiri, Abedin; Gjeli, Selda; Boshnjaku, Arben

    2016-10-01

    This observational, cross-sectional study, investigates and compares the differences of BMD, T-score, Z-score and isometric strength between dominant (D) versus non-dominant (ND) arms of 162 subjects aged 40-65 in a developing, low income country (Kosova). Bone Mineral Density (BMD), T-score and Z-score at distal forearm regions of both arms (measured by DXA scan), together with the Handgrip Isometric Strength (HIS) (by handgrip) were evaluated in a total subjects (53 Males and 109 Females). Additionally, General Healthcare Status Questionnaire together with self-administrated International Physical Activity Questionnaire (IPAQ) were filled. Significant differences (p0.05) were observed in Males BMD comparing to significantly higher results (p0.05) in males. When comparing the total subject's BMD, T-score, Z-score and Handgrip based on the PA levels (1 to 3 according to IPAQ scoring) no significant differences (p>0.05) were found between PA1, as well as PA3 whereas significantly differences (p<0.05) were found in D arms of PA2 level. The study analyses side-to-side differences in bone density and muscular force between D and ND arms amongst a population which is frequently exposed to diagnostic screenings for age related osteomuscular conditions (aged 40-60), and demonstrates that these differences should be in consideration amongst clinicians, but not in the way it is done right now.

  6. Host Plant and Leaf-Age Preference of Luprops tristis (Coleoptera: Tenebrionidae: Lagriinae: Lupropini: A Home Invading Nuisance Pest in Rubber Plantation Belts

    Directory of Open Access Journals (Sweden)

    Sabu K. Thomas

    2012-01-01

    Full Text Available Massive seasonal invasion by the litter-dwelling beetle Luprops tristis, into residential buildings prior to monsoon rains, and their prolonged state of dormancy render them a very serious nuisance pest in rubber plantations in the Western Ghats in southern India. Feeding preferences of L. tristis towards leaf litter of seven trees co-occurring in rubber plantations, cashew (Anacardium occidentale, mango (Mangifera indica, jackfruit (Artocarpus heterophyllus, wild jack (Artocarpus hirsutus, cocoa (Theobroma cacao, cassia (Cassia fistula, sapota (Manilkara zapota and rubber (Hevea brasiliensis were analyzed with no-choice and multiple-choice leaf disc tests. Results showed that L. tristis is a generalist feeder with a defined pattern of preference, with the leaf litter of rubber being the most preferred followed by those of jackfruit and cocoa. Tender leaves were preferred over mature leaves except for cocoa and sapota. Equal preference towards tender and mature cocoa leaves, presence of patches of cocoa plantations and the scarce distribution of other host plants in rubber plantation belts leads to the proposal that in the absence of tender and mature rubber leaves, cocoa becomes the major host plant of L. tristis.

  7. Are bone turnover markers associated with volumetric bone density, size, and strength in older men and women? The AGES-Reykjavik study.

    Science.gov (United States)

    Marques, E A; Gudnason, V; Sigurdsson, G; Lang, T; Johannesdottir, F; Siggeirsdottir, K; Launer, L; Eiriksdottir, G; Harris, T B

    2016-05-01

    Association between serum bone formation and resorption markers and bone mineral, structural, and strength variables derived from quantitative computed tomography (QCT) in a population-based cohort of 1745 older adults was assessed. The association was weak for lumbar spine and femoral neck areal and volumetric bone mineral density. The aim of this study was to examine the relationship between levels of bone turnover markers (BTMs; osteocalcin (OC), C-terminal cross-linking telopeptide of type I collagen (CTX), and procollagen type 1N propeptide (P1NP)) and quantitative computed tomography (QCT)-derived bone density, geometry, and strength indices in the lumbar spine and femoral neck (FN). A total of 1745 older individuals (773 men and 972 women, aged 66-92 years) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik cohort were studied. QCT was performed in the lumbar spine and hip to estimate volumetric trabecular, cortical, and integral bone mineral density (BMD), areal BMD, bone geometry, and bone strength indices. Association between BTMs and QCT variables were explored using multivariable linear regression. Major findings showed that all BMD measures, FN cortical index, and compressive strength had a low negative correlation with the BTM levels in both men and women. Correlations between BTMs and bone size parameters were minimal or not significant. No associations were found between BTMs and vertebral cross-sectional area in women. BTMs alone accounted for only a relatively small percentage of the bone parameter variance (1-10 %). Serum CTX, OC, and P1NP were weakly correlated with lumbar spine and FN areal and volumetric BMD and strength measures. Most of the bone size indices were not associated with BTMs; thus, the selected bone remodeling markers do not reflect periosteal bone formation. These results confirmed the limited ability of the most sensitive established BTMs to predict bone structural integrity in older adults.

  8. Factors in relation to bone mineral density in Korean middle-aged and older men: 2008-2010 Korea National Health and Nutrition Examination Survey.

    Science.gov (United States)

    Yang, Yoon Jung; Kim, Jihye

    2014-01-01

    Studies on determinants of bone mineral density (BMD) among Asian middle-aged and older men are very limited. The aim of this study was to investigate general determinants and dietary factors influencing BMD in Korean middle-aged and older men. This study was conducted using data from the 2008-2010 Korea National Health and Nutrition Examination Survey. A total of 2,305 male subjects aged 50-79 years were included. Whole-body, total femur, femoral neck, and lumbar spine BMDs were measured by dual-energy X-ray absorptiometry. Dietary intake was estimated by 24-hour dietary recall. A food frequency questionnaire for 63 food items was also administered. Proportions of osteoporosis at the total femur, femoral neck, and lumbar spine were 0.7, 3.3 and 7.0%, respectively. Age, height, weight, body mass index, fat mass, lean body mass, waist circumference, serum vitamin D, parathyroid hormone, and exercise were related to BMD, but the relationships were site specific. Diet quality and intake of vegetables, fruits, and calcium were associated with BMD. These results suggest that a high-quality diet, an adequate intake of fruits, vegetables, and calcium, as well as exercise, high serum vitamin D and weight maintenance might be determinants of BMD among middle-aged and older Asian men.

  9. A Genome Wide Association Study on Age at First Calving Using High Density Single Nucleotide Polymorphism Chips in Hanwoo (

    Directory of Open Access Journals (Sweden)

    K.-E. Hyeong

    2014-10-01

    Full Text Available Age at first calving is an important trait for achieving earlier reproductive performance. To detect quantitative trait loci (QTL for reproductive traits, a genome wide association study was conducted on the 96 Hanwoo cows that were born between 2008 and 2010 from 13 sires in a local farm (Juk-Am Hanwoo farm, Suncheon, Korea and genotyped with the Illumina 50K bovine single nucleotide polymorphism (SNP chips. Phenotypes were regressed on additive and dominance effects for each SNP using a simple linear regression model after the effects of birth-year-month and polygenes were considered. A forward regression procedure was applied to determine the best set of SNPs for age at first calving. A total of 15 QTL were detected at the comparison-wise 0.001 level. Two QTL with strong statistical evidence were found at 128.9 Mb and 111.1 Mb on bovine chromosomes (BTA 2 and 7, respectively, each of which accounted for 22% of the phenotypic variance. Also, five significant SNPs were detected on BTAs 10, 16, 20, 26, and 29. Multiple QTL were found on BTAs 1, 2, 7, and 14. The significant QTLs may be applied via marker assisted selection to increase rate of genetic gain for the trait, after validation tests in other Hanwoo cow populations.

  10. Age-related changes of serum tartrate-resistant acid phosphatase 5b and the relationship with bone mineral density in Chinese women

    Institute of Scientific and Technical Information of China (English)

    Yue-juan QIN; Zhen-lin ZHANG; Hao ZHANG; Wei-wei HU; Yu-juan LIU; Yun-qiu HU; Miao LI; Jie-mei GU; Jin-wei HE

    2008-01-01

    Aim: Ostcoclastic activity is mainly assessed by measurement of urinary markers (eg C-terminal cross-linked telopeptides of type I collagen, N-terminal cross-linked telopeptides of type I collagen etc), the levels of which could often be affected by renal clearance. Recently, serum tartrate-resistant acid phosphatase 5b (TRACP5b) has been used as an alternative serum marker to evaluate osteoclastic activity. We investigated the age-related changes of TRACP5b level and its association with bone mineral density (BMD) in Chinese women. Methods: Seven-hundred and twenty-two Chinese mainland women aged 20-79 years were recruited in the study. Serum TRACP5b level was measured using immunoassay to evaluate the state of bone resorption. Bone mineral density (BMD) (g/cm2) at lumbar spine 1-4 and proximal femur were measured by duel-energy X-ray absorptiometry. Results: The serum TRACP5b level reached a bottom value in premenopausal women aged 30-39, gradually increased in women aged 40-49, rapidly rose in women aged 50-59, and culminated with a maximum value in women aged 60-69 before a slow drop in women aged 70-79. The average level of TRACPSb was significantly higher in postmenopausal women [(3.29±1.07) U/L] than in premenopausal women ([1.70±0.59] U/L). The levels of TRACP5b were inversely correlated with BMD at all measured sites (P<0.001). Furthermore, the level of TRACP5b was obviously higher in women with osteoporosis and osteopenia than those with normal bone mass (P<0.001). Conclusion: We have established the reference values of serum TRACPSb in Chinese mainland women, and found that postmenopausal women had higher TRACP5b concentration than younger women. The results showed that serum TRACPSb was a sensitive and useful parameter for the evaluation of age-related changes of bone absorption.

  11. Aging characteristics of blue InGaN micro-light emitting diodes at an extremely high current density of 3.5 kA cm−2

    International Nuclear Information System (INIS)

    Tian, Pengfei; Liu, Ran; Althumali, Ahmad; Gu, Erdan; Watson, Ian M; Dawson, Martin D

    2016-01-01

    The aging characteristics of blue InGaN micro-light emitting diodes (micro-LEDs) with different sizes have been studied at an extremely high current density 3.5 kA cm −2 for emerging micro-LED applications including visible light communication (VLC), micro-LED pumped organic lasers and optogenetics. The light output power of micro-LEDs first increases and then decreases due to the competition of Mg activation in p-GaN layer and defect generation in the active region. The smaller micro-LEDs show less light output power degradation compared with larger micro-LEDs, which is attributed to the lower junction temperature of smaller micro-LEDs. It is found that the high current density without additional junction temperature cannot induce significant micro-LED degradation at room temperature but the combination of the high current density and high junction temperature leads to strong degradation. Furthermore, the cluster LEDs, composed of a micro-LED array, have been developed with both high light output power and less light output degradation for micro-LED applications in solid state lighting and VLC. (paper)

  12. VARIABILITY IN LEVELS OF LOW-DENSITY LIPOPROTEINS CHOLESTEROL IN PATIENTS WITH FAMILIAL HYPERCHOLESTEROLEMIA DEPENDING ON AGE AND SEX AND ITS IMPORTANCE IN THE DIAGNOSIS OF THIS DISEASE

    Directory of Open Access Journals (Sweden)

    V. А. Korneva

    2017-01-01

    Full Text Available Aim. To study the ranges of low density lipoprotein (LDL cholesterol depending on the age and gender of patients with familial hypercholesterolemia (FHC by an example of a sample of patients living in the Republic of Karelia.Material and methods. Parameters of lipid spectrum of 219 patients (aged 52.5±1.7 years; males 38.3% with heterozygous FHC were studied before the start of statin therapy. Definite FHC was diagnosed in 102 patients. Lipid profile was estimated by enzymatic calorimetric method. The diagnosis of FHC was established according to the criteria of The Dutch Lipid Clinic Network.  Genetic analysis was performed in 102 patients (46.6%; pathogenic mutation in the LDL receptor was identified in 21 patients. The control group consisted of 539 people with the excluded diagnosis of FHC (aged 46.8±0.8 years; males 53.8%.Results. We determined the level of LDL cholesterol (LDLC associated with increased frequency of mutations of the LDL receptor in patients with definite FHC; mutation frequency was 3 times higher when LDLC level was more than 6.5 mmol/L. We revealed the following characteristic intervals of the LDLC levels in patients with a definite FHC: up to 20 years old – 4.8-6.2 mmol/l; in patients of 20-29 years old – 5.9-8.2 mmol/l; in the age range of 30-39 years the upper value of the LDLC levels reached 9.6 mmol/l; in individuals of 40-49 years old a stabilization, "plateau", was observed – LDLC level did not differ significantly compared to the previous decade, and was 5.4-9.0 mmol/l. In the age range  of 50-59 years the upper LDLC level was up to 11.4 mmol/l. Similar indicators were identified in patients aged 60-69 years. Patients older than 70 years with a definite FHC an upper level of LDLC was higher and reached 12.5 mmol/l. Tendency to increase in the characteristic values of LDLC with age was observed both in men and in women. Specific age-related trends  for men (an increase from a plateau by the age of 50

  13. Factors associated with bone mineral density and risk of fall in Korean adults with type 2 diabetes mellitus aged 50 years and older.

    Science.gov (United States)

    Lee, Kyoung Min; Chung, Chin Youb; Kwon, Soon-Sun; Lee, Seung Yeol; Kim, Tae Gyun; Choi, Young; Park, Moon Seok

    2014-11-01

    Osteoporotic fractures in subjects with diabetes mellitus (DM) carry higher mortality and morbidity. Because bone strength and minor trauma, such as a falls, are considered to be significant factors contributing to osteoporotic fractures, it is important to elucidate the associated factors with these. This study was performed to investigate the factors associated with bone mineral density (BMD) and falls in noninstitutionalized subjects with DM aged 50 years or older. We used the database from the 2010 Fifth Korea National Health and Nutrition Examination Survey. Subjects with DM aged 50 years or older were selected and included in the data analyses. Associated factors with BMD of the femoral neck and lumbar spine and those with falls were analyzed using multiple linear regression and binary logistic regression analyses, respectively. Three hundred sixty-two subjects [209 males; 153 females; average age, 66.0 y (SD 8.2 y)] were included. Among the male subjects, the total body muscle mass (P factors with femoral neck BMD, whereas age (P risk of falls. Total body muscle mass was the most prominent factor predicting femoral neck BMD and risk of falls in community-dwelling elderly subjects with DM. Further investigation is required to determine their role in preventing osteoporotic fractures in diabetic subjects.

  14. Age-Related Loss in Bone Mineral Density of Rats Fed Lifelong on a Fish Oil-Based Diet Is Avoided by Coenzyme Q10 Addition

    Directory of Open Access Journals (Sweden)

    Alfonso Varela-López

    2017-02-01

    Full Text Available During aging, bone mass declines increasing osteoporosis and fracture risks. Oxidative stress has been related to this bone loss, making dietary compounds with antioxidant properties a promising weapon. Male Wistar rats were maintained for 6 or 24 months on diets with fish oil as unique fat source, supplemented or not with coenzyme Q10 (CoQ10, to evaluate the potential of adding this molecule to the n-3 polyunsaturated fatty acid (n-3 PUFA-based diet for bone mineral density (BMD preservation. BMD was evaluated in the femur. Serum osteocalcin, osteopontin, receptor activator of nuclear factor-κB ligand, ostroprotegerin, parathyroid hormone, urinary F2-isoprostanes, and lymphocytes DNA strand breaks were also measured. BMD was lower in aged rats fed a diet without CoQ10 respect than their younger counterparts, whereas older animals receiving CoQ10 showed the highest BMD. F2-isoprostanes and DNA strand breaks showed that oxidative stress was higher during aging. Supplementation with CoQ10 prevented oxidative damage to lipid and DNA, in young and old animals, respectively. Reduced oxidative stress associated to CoQ10 supplementation of this n-3 PUFA-rich diet might explain the higher BMD found in aged rats in this group of animals.

  15. Relationship between pure Schistosoma haematobium infection in Upper Egypt and irrigation systems. Part II: Host characteristics. The general prevalence of Schistosoma haematobium, age and sex distribution.

    Science.gov (United States)

    Hammam, H M; Allam, F A; Hassanein, F

    1975-01-01

    The epidemiology of bilharziasis was studied in four villages in Assiut Governorate. These villages were almost similar with respect to their socioeconomic conditions, modes of living, availability and date of introduction of medical services. The first village, Gezirat El-Maabda, has a basin system of irrigation. The other three villages had shifted to the perennial system of irrigation for three years in Nazza Karrar, 26 years in El-Ghorayeb and 95 years in Garf Sarhan and were similar with respect to proximity to water courses. So the only variable of importance between the four villages was the mode of irrigation. Bilharziasis was diagnosed by detection of eggs in urine or faeces. A definitive relationship between the prevalence of S. haematobium infection and the type of irrigation system was further documented. A low prevalence was found in Gezirat El-Maabda (2.95%). In the other three villages a much higher prevalence existed (31.9%, 46.2% & 38.9% in Nazza Karar, El-Ghorayeb and Garf Sarhan respectively). The higher prevalence of S. haematobium in Nazza Karar (31.9%) only three years after introduction of perennial irrigation was a disappointing finding. It can be considered as an evidence against the elaborate measures and precautions planned and incompletely implemented before or after the establishment of Aswan High Dam. Not a single case of S. mansoni was encountered during this study. As regards the age and sex distribution of S. haematobium in the three villages irrigated perennially, a steep rise started at the age group 5-9 years reaching a peak at the age group 10-14 years. In Gezirat El-Maabda the peak was reached at later age (15-19 years). The cause of this difference was explained. Males showed a higher rate of infection than females in almost all age groups of the four village studied.

  16. Bone mineral density, muscle strength and physical activity. A population-based study of 332 subjects aged 15-42 years.

    Science.gov (United States)

    Düppe, H; Gärdsell, P; Johnell, O; Nilsson, B E; Ringsberg, K

    1997-04-01

    The aim of this population-based study was to find out whether differences in levels of physical activity have an influence on bone mass quantity and whether quadriceps muscle strength is a reliable determinant of bone mass. Included were 175 men and 157 women, aged 15-42 years. Bone mineral density (BMD) was measured at various sites by dual X-ray absorptiometry (DXA) and single photon absorptiometry (SPA). Muscle strength was assessed using an isokinetic muscle force meter. A questionnaire was used to estimate the level of physical activity. We found a positive correlation between physical activity and BMD for boys at the distal forearm and for girls at the trochanter (age group 15-16 years). Active men (age group 21-42 years) had up to 9% higher BMD levels at the hip than those who were less active. Quadriceps muscle torque was not an independent predictor of BMD. Our data suggest that a higher level of physical activity-within the limits of a "normal life style"-may have a positive effect on BMD in the proximal femur of young adults, which in turn may lessen the subsequent risk of fracture.

  17. [Tuberculosis in compromised hosts].

    Science.gov (United States)

    2003-11-01

    among patients with pulmonary tuberculosis was 8.4 percent. The mean age of gastric resection was 50.2 +/- 16.6 years, and the mean interval from gastrectomy to pulmonary tuberculosis was 13.6 +/- 11.0 years. On admission to our hospital, 34 out of 55 cases were smear positive by sputum examination for acid-fast bacilli and 39 cases had cavitary lesions on chest X-ray. Gastrectomy was done due to carcinoma of the stomach in 31 cases, gastric and/or duodenal ulcer in 21 cases, adenomatous polyp in two cases, and accidental injury in one case. 52 patients improved, but three cases died due to pulmonary tuberculosis. No one had recurrence of carcinoma of the stomach. Body weight, Body Mass Index, Prognostic Nutritional Index (PNI; 10x serum albumin concentration +0.005 x peripheral lymphocyte count) which was proposed by Onodera, serum albumin level and serum total cholesterol level were lower in the gastrectomy group than in the non-gastrectomy group. I calculated the odds of tuberculosis among gastrectomy patients to be 3.8 times that of appropriate controls. This study confirms that gastrectomy is one of the risk factor(s) of tuberculosis. However, whether gastrectomy in itself is a risk factor or whether it is secondarily associated with another risk factor such as underweight status and/or inadequate nutrition following surgery remains unclear. 3. Immunodefficiency and tuberculosis in dialysis patients: Hajime INAMOTO (Division of Dialysis, Keio University School of Medicine). The patients who have renal insufficiency is fatal, but they can live much longer by dialysis. The number of lymphocytes of the patients whose serum creatinine was 10 mg/dl or more has decreased to about 50% of the people who have normal kidney. When the lymphocyte was cultured after it was stimulated with PHA, the DNA synthesis of the patients' lymphocyte was much lower than that of the modest people's. In the dialysis food, the nutrient such as vitamins, minerals, etc. were lacked. The density

  18. Breast density does not impact the ability of Videssa® Breast to detect breast cancer in women under age 50.

    Directory of Open Access Journals (Sweden)

    David E Reese

    Full Text Available Breast density is associated with reduced imaging resolution in the detection of breast cancer. A biochemical approach that is not affected by density would provide an important tool to healthcare professionals who are managing women with dense breasts and suspicious imaging findings. Videssa® Breast is a combinatorial proteomic biomarker assay (CPBA, comprised of Serum Protein Biomarkers (SPB and Tumor Associated Autoantibodies (TAAb integrated with patient-specific clinical data to produce a diagnostic score that reliably detects breast cancer (BC as an adjunctive tool to imaging. The performance of Videssa® Breast was evaluated in the dense (a and b and non-dense (c and d groups in a population of n = 545 women under age 50. The sensitivity and specificity in the dense breast group were calculated to be 88.9% and 81.2%, respectively, and 92.3% and 86.6%, respectively, for the non-dense group. No significant differences were observed in the sensitivity (p = 1.0 or specificity (p = 0.18 between these groups. The NPV was 99.3% and 99.1% in non-dense and dense groups, respectively. Unlike imaging, Videssa® Breast does not appear to be impacted by breast density; it can effectively detect breast cancer in women with dense and non-dense breasts alike. Thus, Videssa® Breast provides a powerful tool for healthcare providers when women with dense breasts present with challenging imaging findings. In addition, Videssa® Breast provides assurance to women with dense breasts that they do not have breast cancer, reducing further anxiety in this higher risk patient population.

  19. Effect of first line cancer treatment on the ovarian reserve and follicular density in girls under the age of 18 years

    DEFF Research Database (Denmark)

    El Issaoui, Meryam; Giorgione, Veronica; Mamsen, Linn S

    2016-01-01

    the age of 18 years who underwent OTC before (group 1: 31 patients) and after (group 2: 32 patients) their initial cancer treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Follicular densities (follicles/mm(3)) measured from an ovarian cortical biopsy before OTC. The ovarian volume (mL) of entire...... to have little effect on the follicle pool. This information will improve counseling of young female cancer patients in deciding whether to undergo fertility preservation treatment.......OBJECTIVE: To study the impact of first-line antineoplastic treatment on ovarian reserve in young girls returning for ovarian tissue cryopreservation (OTC) in connection with a relapse. DESIGN: Retrospective case-control study. SETTING: University hospitals. PATIENT(S): Sixty-three girls under...

  20. The bone mass density in men aged over 50 and its relation to the concentration of free and total testosterone in the blood serum

    International Nuclear Information System (INIS)

    Purzycka-Jazdon, A.; Lasek, W.; Serafin, Z.; Manysiak, S.

    2003-01-01

    As the mean length of life increases, osteoporosis affects a growing number of men and women, thus becoming an important medical and socioeconomic problem in many countries. Pathogenesis and the prevalence of the osteoporosis in women are well established, however, in men, they are still controversial. In this study, the bone mass density (BMD) of the lumbar spine was determined in 100 healthy men age 50-83, using quantitative computed tomography (QCT). Also, the total serum and free testosterone was measured. The mean BMD was 123.1I39.3 mg/cm 3 , and the values below a fracture threshold were noted in 39% of subjects. The mean concentration of total and free serum testosterone was 4.3I1.7 ng/ml and 6.2I3.7 pg/ml, respectively. There was a significant (p 3 , respectively). There was no correlation found between total testosterone and BMD. Results indicate that reduced bone mass density in males over 50 is as frequent as recently reported in females. Moreover, sex hormones seem to be related to osteoporosis development in men as well. (author)

  1. Should breast MRI be performed with adjustment for the phase in patients’ menstrual cycle? Correlation between mammographic density, age, and background enhancement on breast MRI without adjusting for the phase in patients’ menstrual cycle

    International Nuclear Information System (INIS)

    Uematsu, Takayoshi; Kasami, Masako; Watanabe, Junichiro

    2012-01-01

    Purpose: The purpose of this study was to assess the correlation between mammographic density, age, and background enhancement on breast MRI without adjusting for the phase in patients’ menstrual cycle. Material and methods: The background enhancement of bilateral breast MRI and the breast density of mammography in 146 consecutive women without adjusting for the phase in patients’ menstrual cycle were reviewed. The breast density was classified into four categories according to the American College of Radiology the Breast Imaging Reporting and Data System lexicon. The background enhancement was classified into four categories: minimal, mild, moderate, and marked. The correlations of mammographic breast density as well as age with background enhancement on breast MRI were examined. Results: There was a significant correlation between mammographic breast density and background enhancement (p = 0.011). All nine cases with almost completely fat mammographic breast density showed minimal (78%) or mild (12%) background enhancement on breast MRI. There was a significant inverse correlation between age and background enhancement (p < 0.0001). Younger patients with dense breasts were more likely to demonstrate moderate/marked background enhancement. Conclusion: When no adjusting for the phase in patients’ menstrual cycle, a significant correlation was observed between background enhancement and mammographic density. A significant inverse correlation was also observed between age and background enhancement.

  2. Environmentally transmitted parasites: Host-jumping in a heterogeneous environment.

    Science.gov (United States)

    Caraco, Thomas; Cizauskas, Carrie A; Wang, Ing-Nang

    2016-05-21

    Groups of chronically infected reservoir-hosts contaminate resource patches by shedding a parasite׳s free-living stage. Novel-host groups visit the same patches, where they are exposed to infection. We treat arrival at patches, levels of parasite deposition, and infection of the novel host as stochastic processes, and derive the expected time elapsing until a host-jump (initial infection of a novel host) occurs. At stationarity, mean parasite densities are independent of reservoir-host group size. But within-patch parasite-density variances increase with reservoir group size. The probability of infecting a novel host declines with parasite-density variance; consequently larger reservoir groups extend the mean waiting time for host-jumping. Larger novel-host groups increase the probability of a host-jump during any single patch visit, but also reduce the total number of visits per unit time. Interaction of these effects implies that the waiting time for the first infection increases with the novel-host group size. If the reservoir-host uses resource patches in any non-uniform manner, reduced spatial overlap between host species increases the waiting time for host-jumping. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Diagnostic value of palpation, mammography, and ultrasonography in the diagnosis of fibroadenoma: impact of breast density, patient age, ultrasonographic size, and palpability.

    Science.gov (United States)

    Zimmermann, N; Ohlinger, R

    2012-12-01

    This retrospective study aimed to assess the diagnostic value of mammography, breast ultrasonography, and palpation in diagnosing fibroadenomas, making consistent use of the BI-RADS classification. The impact of breast density, patient age, and the size and palpability of the mass will be evaluated. Between January 2000 and December 2009, a total of 339 fibroadenomas suitable for inclusion in this study were diagnosed and histologically verified at our institution. Based on their BI-RADS or BI-RADS analog classification, all lesions were categorized as benign or malignant. These results were compared to the corresponding histopathological findings. Specificities were calculated for each of the abovementioned parameters. Chi-square test results with p-values  1.9 cm (κ = 0.464, κ = 0.444). For diagnosing fibroadenomas, ultrasonography is more specific than mammography when all examined variables are taken into account. Ultrasonography should therefore be favored, especially in younger patients. One needs to be aware of the effects of palpability and patient age on the ultrasonographic differentiation "malignant" vs. "benign". In some cases, mammography should be considered as an adjunct. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Wheel running from a juvenile age delays onset of specific motor deficits but does not alter protein aggregate density in a mouse model of Huntington's disease

    Directory of Open Access Journals (Sweden)

    Spires Tara L

    2008-04-01

    Full Text Available Abstract Background Huntington's disease (HD is a neurodegenerative disorder predominantly affecting the cerebral cortex and striatum. Transgenic mice (R6/1 line, expressing a CAG repeat encoding an expanded polyglutamine tract in the N-terminus of the huntingtin protein, closely model HD. We have previously shown that environmental enrichment of these HD mice delays the onset of motor deficits. Furthermore, wheel running initiated in adulthood ameliorates the rear-paw clasping motor sign, but not an accelerating rotarod deficit. Results We have now examined the effects of enhanced physical activity via wheel running, commenced at a juvenile age (4 weeks, with respect to the onset of various behavioral deficits and their neuropathological correlates in R6/1 HD mice. HD mice housed post-weaning with running wheels only, to enhance voluntary physical exercise, have delayed onset of a motor co-ordination deficit on the static horizontal rod, as well as rear-paw clasping, although the accelerating rotarod deficit remains unaffected. Both wheel running and environmental enrichment rescued HD-induced abnormal habituation of locomotor activity and exploratory behavior in the open field. We have found that neither environment enrichment nor wheel running ameliorates the shrinkage of the striatum and anterior cingulate cortex (ACC in HD mice, nor the overall decrease in brain weight, measured at 9 months of age. At this age, the density of ubiquitinated protein aggregates in the striatum and ACC is also not significantly ameliorated by environmental enrichment or wheel running. Conclusion These results indicate that enhanced voluntary physical activity, commenced at an early presymptomatic stage, contributes to the positive effects of environmental enrichment. However, sensory and cognitive stimulation, as well as motor stimulation not associated with running, may constitute major components of the therapeutic benefits associated with enrichment

  5. Assessment of association of smoking with bone mineral density (BMD) and fragility fractures in a cohort of pakistani males ages <= 50 years and postmenopausal females

    International Nuclear Information System (INIS)

    Akhlaq, U.; Ayaz, S.B.

    2015-01-01

    Objectives: The study aimed to determine the association between smoking, bone mineral density (BMD), and fragility fractures in a cohort of Pakistani males aged > 50 years and postmenopausal females. Methodology: This was a cross-sectional survey carried out at Armed Forces Institute of Rehabilitation Medicine (AFIRM), Rawalpindi from Jan 2010 to Jan 2011. Through non-probability purposive sampling, we included male patients of age > 50 years and postmenopausal women. All subjects were submitted to dual energy X-Ray absorptiometery at lumbar spine (L2 > L4) and at both femoral by Hologic Discovery-A machine . The lowest BMD was noted and expressed in the form of T-score.Using SPSS V 20, descriptive statistics were calculated for the various variables. Independent samples t-test was used to determine the significance of difference between mean T-score in between smokers and non-smokers. Association between smoking and the risk of fracture was carried out using Fisher exact test. A p-value < 0.05 was considered significant. Results: Out of a total of 328 patients, 142 (43.3%) were male (mean age 64 ± 8, range: 50 - 82 years) and 186 (56.7%) were female (mean age 61 ± 8, range: 43 - 92 years). Sixteen (8.6%) females and 52 (36.6%) males were smokers. In males, the mean T-score was -1.6 ± 1.3 in non-smokers and -1.9 ± 1.2 in smokers (p=0.17). Two of the non-smokers and nine of the smokers had a fracture. (p=0.002). In females, the mean T-score was -2.9 ± 1.9 in smokers and -2.3 ± 1.4 in non-smokers (p=0.23). Twelve of the non-smokers and 15 smokers had a fracture. (p<0.001) Conclusion: Smoking was significantly associated with increased percentage of fragility fractures but not with a reduction in BMD in our sample of postmenopausal women and men of age > 50 years. (author)

  6. Mesoscale spatiotemporal variability in a complex host-parasite system influenced by intermediate host body size

    Directory of Open Access Journals (Sweden)

    Sara M. Rodríguez

    2017-08-01

    Full Text Available Background Parasites are essential components of natural communities, but the factors that generate skewed distributions of parasite occurrences and abundances across host populations are not well understood. Methods Here, we analyse at a seascape scale the spatiotemporal relationships of parasite exposure and host body-size with the proportion of infected hosts (i.e., prevalence and aggregation of parasite burden across ca. 150 km of the coast and over 22 months. We predicted that the effects of parasite exposure on prevalence and aggregation are dependent on host body-sizes. We used an indirect host-parasite interaction in which migratory seagulls, sandy-shore molecrabs, and an acanthocephalan worm constitute the definitive hosts, intermediate hosts, and endoparasite, respectively. In such complex systems, increments in the abundance of definitive hosts imply increments in intermediate hosts’ exposure to the parasite’s dispersive stages. Results Linear mixed-effects models showed a significant, albeit highly variable, positive relationship between seagull density and prevalence. This relationship was stronger for small (cephalothorax length >15 mm than large molecrabs (<15 mm. Independently of seagull density, large molecrabs carried significantly more parasites than small molecrabs. The analysis of the variance-to-mean ratio of per capita parasite burden showed no relationship between seagull density and mean parasite aggregation across host populations. However, the amount of unexplained variability in aggregation was strikingly higher in larger than smaller intermediate hosts. This unexplained variability was driven by a decrease in the mean-variance scaling in heavily infected large molecrabs. Conclusions These results show complex interdependencies between extrinsic and intrinsic population attributes on the structure of host-parasite interactions. We suggest that parasite accumulation—a characteristic of indirect host

  7. Phengaris (Maculinea) teleius butterflies select host plants close to Myrmica ants for oviposition, but P. nausithous do not

    NARCIS (Netherlands)

    Wynhoff, Irma; Langevelde, van Frank

    2017-01-01

    Many lycaenid butterfly species have interactions with ants, with 12% obligatorily depending on two sequential sources of larval food, namely host plants and host ants. When host plants are abundant but the density of host ant nests is relatively low, most host plants have no host ant nest in their

  8. Mesoscale spatiotemporal variability in a complex host-parasite system influenced by intermediate host body size.

    Science.gov (United States)

    Rodríguez, Sara M; Valdivia, Nelson

    2017-01-01

    Parasites are essential components of natural communities, but the factors that generate skewed distributions of parasite occurrences and abundances across host populations are not well understood. Here, we analyse at a seascape scale the spatiotemporal relationships of parasite exposure and host body-size with the proportion of infected hosts (i.e., prevalence) and aggregation of parasite burden across ca. 150 km of the coast and over 22 months. We predicted that the effects of parasite exposure on prevalence and aggregation are dependent on host body-sizes. We used an indirect host-parasite interaction in which migratory seagulls, sandy-shore molecrabs, and an acanthocephalan worm constitute the definitive hosts, intermediate hosts, and endoparasite, respectively. In such complex systems, increments in the abundance of definitive hosts imply increments in intermediate hosts' exposure to the parasite's dispersive stages. Linear mixed-effects models showed a significant, albeit highly variable, positive relationship between seagull density and prevalence. This relationship was stronger for small (cephalothorax length >15 mm) than large molecrabs (analysis of the variance-to-mean ratio of per capita parasite burden showed no relationship between seagull density and mean parasite aggregation across host populations. However, the amount of unexplained variability in aggregation was strikingly higher in larger than smaller intermediate hosts. This unexplained variability was driven by a decrease in the mean-variance scaling in heavily infected large molecrabs. These results show complex interdependencies between extrinsic and intrinsic population attributes on the structure of host-parasite interactions. We suggest that parasite accumulation-a characteristic of indirect host-parasite interactions-and subsequent increasing mortality rates over ontogeny underpin size-dependent host-parasite dynamics.

  9. Cultural intensity and planting density effects on individual tree stem growth, stand and crown attributes, and stand dynamics in thinned loblolly pine plantations during the age 12- to age 15- year period in the Upper Coastal Plain and Piedmont of the Southeastern United States

    Science.gov (United States)

    Evan Johnson; Michael Kane; Dehai Zhao; Robert Teskey

    2015-01-01

    Three existing loblolly pine (Pinus taeda L.) installations in the Plantation Management Research Cooperative's Upper Coastal Plain/Piedmont Culture Density Study were used to examine the effects of two cultural intensities, four initial planting densities, and their interactions on stem growth at the individual tree level from age 12 to 15 years and at the stand...

  10. The effects of host-feeding on stability of discrete-time host-parasitoid population dynamic models.

    Science.gov (United States)

    Emerick, Brooks; Singh, Abhyudai

    2016-02-01

    Discrete-time models are the traditional approach for capturing population dynamics of a host-parasitoid system. Recent work has introduced a semi-discrete framework for obtaining model update functions that connect host-parasitoid population levels from year-to-year. In particular, this framework uses differential equations to describe the host-parasitoid interaction during the time of year when they come in contact, allowing specific behaviors to be mechanistically incorporated. We use the semi-discrete approach to study the effects of host-feeding, which occurs when a parasitoid consumes a potential host larva without ovipositing. We find that host-feeding by itself cannot stabilize the system, and both populations exhibit behavior similar to the Nicholson-Bailey model. However, when combined with stabilizing mechanisms such as density-dependent host mortality, host-feeding contracts the region of parameter space that allows for a stable host-parasitoid equilibrium. In contrast, when combined with a density-dependent parasitoid attack rate, host-feeding expands the non-zero equilibrium stability region. Our results show that host-feeding causes inefficiency in the parasitoid population, which yields a higher population of hosts per generation. This suggests that host-feeding may have limited long-term impact in terms of suppressing host levels for biological control applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. 3D printed Ti6Al4V implant surface promotes bone maturation and retains a higher density of less aged osteocytes at the bone-implant interface.

    Science.gov (United States)

    Shah, Furqan A; Snis, Anders; Matic, Aleksandar; Thomsen, Peter; Palmquist, Anders

    2016-01-01

    For load-bearing orthopaedic applications, metal implants having an interconnected pore structure exhibit the potential to facilitate bone ingrowth and the possibility for reducing the stiffness mismatch between the implant and bone, thus eliminating stress-shielding effects. 3D printed solid and macro-porous Ti6Al4V implants were evaluated after six-months healing in adult sheep femora. The ultrastructural composition of the bone-implant interface was investigated using Raman spectroscopy and electron microscopy, in a correlative manner. The mineral crystallinity and the mineral-to-matrix ratios of the interfacial tissue and the native bone were found to be similar. However, lower Ca/P ratios, lower carbonate content, but higher proline, phenylalanine and tyrosine levels indicated that the interfacial tissue remained less mature. Bone healing was more advanced at the porous implant surface (vs. the solid implant surface) based on the interfacial tissue ν1 CO3(2-)/ν2 PO4(3-) ratio, phenylalanine and tyrosine levels approaching those of the native bone. The mechanosensing infrastructure in bone, the osteocyte lacuno-canalicular network, retained ∼40% more canaliculi per osteocyte lacuna, i.e., a 'less aged' morphology at the interface. The osteocyte density per mineralised surface area was ∼36-71% higher at the interface after extended healing periods. In osseointegration research, the success of an implant surface or design is commonly determined by quantifying the amount of new bone, rather than its maturation, composition and structure. This work describes a novel correlative methodology to investigate the ultrastructure and composition of bone formed around and within 3D printed Ti6Al4V implants having an interconnected open-pore structure. Raman spectroscopy demonstrates that the molecular composition of the interfacial tissue at different implant surfaces may vary, suggesting differences in the extent to which bone maturation occurs even after long

  12. The Influence of Sampling Density on Bayesian Age-Depth Models and Paleoclimatic Reconstructions - Lessons Learned from Lake Titicaca - Bolivia/Peru

    Science.gov (United States)

    Salenbien, W.; Baker, P. A.; Fritz, S. C.; Guedron, S.

    2014-12-01

    Lake Titicaca is one of the most important archives of paleoclimate in tropical South America, and prior studies have elucidated patterns of climate variation at varied temporal scales over the past 0.5 Ma. Yet, slow sediment accumulation rates in the main deeper basin of the lake have precluded analysis of the lake's most recent history at high resolution. To obtain a paleoclimate record of the last few millennia at multi-decadal resolution, we obtained five short cores, ranging from 139 to 181 cm in length, from the shallower Wiñaymarka sub-basin of of Lake Titicaca, where sedimentation rates are higher than in the lake's main basin. Selected cores have been analyzed for their geochemical signature by scanning XRF, diatom stratigraphy, sedimentology, and for 14C age dating. A total of 72 samples were 14C-dated using a Gas Ion Source automated high-throughput method for carbonate samples (mainly Littoridina sp. and Taphius montanus gastropod shells) at NOSAMS (Woods Hole Oceanographic Institute) with an analytical precision higher than 2%. The method has lower analytical precision compared with traditional AMS radiocarbon dating, but the lower cost enables analysis of a larger number of samples, and the error associated with the lower precision is relatively small for younger samples (< ~8,000 years). A 172-cm-long core was divided into centimeter long sections, and 47 14C dates were obtained from 1-cm intervals, averaging one date every 3-4 cm. The other cores were radiocarbon dated with a sparser sampling density that focused on visual unconformities and shell beds. The high-resolution radiocarbon analysis reveals complex sedimentation patterns in visually continuous sections, with abundant indicators of bioturbated or reworked sediments and periods of very rapid sediment accumulation. These features are not evident in the sparser sampling strategy but have significant implications for reconstructing past lake level and paleoclimatic history.

  13. Lean mass and fat mass predict bone mineral density in middle-aged individuals with noninsulin-requiring type 2 diabetes mellitus.

    Science.gov (United States)

    Moseley, Kendall F; Dobrosielski, Devon A; Stewart, Kerry J; De Beur, Suzanne M Jan; Sellmeyer, Deborah E

    2011-05-01

    Despite high bone mineral density (BMD), persons with type 2 diabetes are at greater risk of fracture. The relationship between body composition and BMD in noninsulin-requiring diabetes is unclear. The aim was to examine how fat and lean mass independently affect the skeleton in this population. Subjects for this cross-sectional analysis were men (n = 78) and women (n = 56) aged 40-65 years (56 ± 6 years) with uncomplicated, noninsulin-requiring type 2 diabetes. Total body fat and lean mass, total body, hip and lumbar spine BMD were measured with dual energy X-ray absorptiometry. Magnetic resonance imaging measured total abdominal, visceral and subcutaneous (SQ) fat. Subjects had normal all-site BMD and were obese to overweight (body mass index 29-41 kg/m(2)) with controlled diabetes (HbA1c women 6·6 ± 1·2%, men 6·7 ± 1·6%). Lean mass was positively associated with total body, hip, femoral neck and hip BMD in both sexes. Fat mass, abdominal total and SQ fat were associated with total body and hip BMD in women. In multivariate analyses adjusted for sex, lean mass significantly predicted total, hip and femoral neck BMD in men and women. In unadjusted models, lean mass continued to predict BMD at these sites in men; fat mass also predicted total body, femoral and hip BMD in women. In men and women with uncomplicated, noninsulin-requiring diabetes, lean mass significantly predicted BMD at the total body, hip and femoral neck. Further research is needed to determine whether acquisition or maintenance of lean mass in T2DM can prevent hip fracture in this at-risk population. © 2011 Blackwell Publishing Ltd.

  14. Genetic variants near TIMP3 and high-density lipoprotein–associated loci influence susceptibility to age-related macular degeneration

    Science.gov (United States)

    Chen, Wei; Stambolian, Dwight; Edwards, Albert O.; Branham, Kari E.; Othman, Mohammad; Jakobsdottir, Johanna; Tosakulwong, Nirubol; Pericak-Vance, Margaret A.; Campochiaro, Peter A.; Klein, Michael L.; Tan, Perciliz L.; Conley, Yvette P.; Kanda, Atsuhiro; Kopplin, Laura; Li, Yanming; Augustaitis, Katherine J.; Karoukis, Athanasios J.; Scott, William K.; Agarwal, Anita; Kovach, Jaclyn L.; Schwartz, Stephen G.; Postel, Eric A.; Brooks, Matthew; Baratz, Keith H.; Brown, William L.; Brucker, Alexander J.; Orlin, Anton; Brown, Gary; Ho, Allen; Regillo, Carl; Donoso, Larry; Tian, Lifeng; Kaderli, Brian; Hadley, Dexter; Hagstrom, Stephanie A.; Peachey, Neal S.; Klein, Ronald; Klein, Barbara E. K.; Gotoh, Norimoto; Yamashiro, Kenji; Ferris, Frederick; Fagerness, Jesen A.; Reynolds, Robyn; Farrer, Lindsay A.; Kim, Ivana K.; Miller, Joan W.; Cortón, Marta; Carracedo, Angel; Sanchez-Salorio, Manuel; Pugh, Elizabeth W.; Doheny, Kimberly F.; Brion, Maria; DeAngelis, Margaret M.; Weeks, Daniel E.; Zack, Donald J.; Chew, Emily Y.; Heckenlively, John R.; Yoshimura, Nagahisa; Iyengar, Sudha K.; Francis, Peter J.; Katsanis, Nicholas; Seddon, Johanna M.; Haines, Jonathan L.; Gorin, Michael B.; Abecasis, Gonçalo R.; Swaroop, Anand; Johnson, Robert N.; Ai, Everett; McDonald, H. Richard; Stolarczuk, Margaret; Pavan, Peter Reed; Billiris, Karina K.; Iyer, Mohan; Menosky, Matthew M.; Pautler, Scott E.; Millard, Sharon M.; Hubbard, Baker; Aaberg, Thomas; DuBois, Lindy; Lyon, Alice; Anderson-Nelson, Susan; Jampol, Lee M.; Weinberg, David V.; Muñana, Annie; Rozenbajgier, Zuzanna; Orth, David; Cohen, Jack; MacCumber, Matthew; MacCumber, Matthew; Figliulo, Celeste; Porcz, Liz; Folk, James; Boldt, H. Culver; Russell, Stephen R.; Ivins, Rachel; Hinz, Connie J.; Barr, Charles C.; Bloom, Steve; Jaegers, Ken; Kritchman, Brian; Whittington, Greg; Heier, Jeffrey; Frederick, Albert R.; Morley, Michael G.; Topping, Trexler; Davis, Heather L.; Bressler, Susan B.; Bressler, Neil M.; Doll, Warren; Trese, Michael; Capone, Antonio; Garretson, Bruce R.; Hassan, Tarek S.; Ruby, Alan J.; Osentoski, Tammy; McCannel, Colin A.; Ruszczyk, Margaret J.; Grand, Gilbert; Blinder, Kevin; Holekamp, Nancy M.; Joseph, Daniel P.; Shah, Gaurav; Nobel, Ginny S.; Antoszyk, Andrew N.; Browning, David J.; Stallings, Alison H; Singerman, Lawrence J.; Miller, David; Novak, Michael; Pendergast, Scott; Zegarra, Hernando; Schura, Stephanie A.; Smith-Brewer, Sheila; Davidorf, Frederick H.; Chambers, Robert; Chorich, Louis; Salerno, Jill; Dreyer, Richard F.; Ma, Colin; Kopfer, Marcia R.; Klein, Michael L.; Wilson, David J.; Nolte, Susan K.; Grunwald, Juan E.; Brucker, Alexander J.; Dunaief, Josh; Fine, Stuart L.; Maguire, Albert M.; Stoltz, Robert A.; McRay, Monique N.; Fish, Gary Edd; Anand, Rajiv; Spencer, Rand; Arnwine, Jean; Chandra, Suresh R.; Altaweel, Michael; Blodi, Barbara; Gottlieb, Justin; Ip, Michael; Nork, T. Michael; Perry-Raymond, Jennie; Fine, Stuart L.; Maguire, Maureen G.; Brightwell-Arnold, Mary; Harkins, Sandra; Peskin, Ellen; Ying, Gui-Shuang; Kurinij, Natalie

    2010-01-01

    We executed a genome-wide association scan for age-related macular degeneration (AMD) in 2,157 cases and 1,150 controls. Our results validate AMD susceptibility loci near CFH (P < 10−75), ARMS2 (P < 10−59), C2/CFB (P < 10−20), C3 (P < 10−9), and CFI (P < 10−6). We compared our top findings with the Tufts/Massachusetts General Hospital genome-wide association study of advanced AMD (821 cases, 1,709 controls) and genotyped 30 promising markers in additional individuals (up to 7,749 cases and 4,625 controls). With these data, we identified a susceptibility locus near TIMP3 (overall P = 1.1 × 10−11), a metalloproteinase involved in degradation of the extracellular matrix and previously implicated in early-onset maculopathy. In addition, our data revealed strong association signals with alleles at two loci (LIPC, P = 1.3 × 10−7; CETP, P = 7.4 × 10−7) that were previously associated with high-density lipoprotein cholesterol (HDL-c) levels in blood. Consistent with the hypothesis that HDL metabolism is associated with AMD pathogenesis, we also observed association with AMD of HDL-c—associated alleles near LPL (P = 3.0 × 10−3) and ABCA1 (P = 5.6 × 10−4). Multilocus analysis including all susceptibility loci showed that 329 of 331 individuals (99%) with the highest-risk genotypes were cases, and 85% of these had advanced AMD. Our studies extend the catalog of AMD associated loci, help identify individuals at high risk of disease, and provide clues about underlying cellular pathways that should eventually lead to new therapies. PMID:20385819

  15. THE LOCAL HOSTS OF TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Neill, James D.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Wyder, Ted K.; Sullivan, Mark; Howell, D. Andrew; Conley, Alex; Seibert, Mark; Madore, Barry F.; Neff, Susan G.; Schiminovich, David; Bianchi, Luciana; Donas, Jose; Milliard, Bruno; Heckman, Timothy M.; Lee, Young-Wook; Rich, R. Michael

    2009-01-01

    We use multi-wavelength, matched aperture, integrated photometry from the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the RC3 to estimate the physical properties of 166 nearby galaxies hosting 168 well-observed Type Ia supernovae (SNe Ia). The ultraviolet (UV) imaging of local SN Ia hosts from GALEX allows a direct comparison with higher-redshift hosts measured at optical wavelengths that correspond to the rest-frame UV. Our data corroborate well-known features that have been seen in other SN Ia samples. Specifically, hosts with active star formation produce brighter and slower SNe Ia on average, and hosts with luminosity-weighted ages older than 1 Gyr produce on average more faint, fast, and fewer bright, slow SNe Ia than younger hosts. New results include that in our sample, the faintest and fastest SNe Ia occur only in galaxies exceeding a stellar mass threshold of ∼10 10 M sun , leading us to conclude that their progenitors must arise in populations that are older and/or more metal rich than the general SN Ia population. A low host extinction subsample hints at a residual trend in peak luminosity with host age, after correcting for light-curve shape, giving the appearance that older hosts produce less-extincted SNe Ia on average. This has implications for cosmological fitting of SNe Ia, and suggests that host age could be useful as a parameter in the fitting. Converting host mass to metallicity and computing 56 Ni mass from the supernova light curves, we find that our local sample is consistent with a model that predicts a shallow trend between stellar metallicity and the 56 Ni mass that powers the explosion, but we cannot rule out the absence of a trend. We measure a correlation between 56 Ni mass and host age in the local universe that is shallower and not as significant as that seen at higher redshifts. The details of the age- 56 Ni mass correlations at low and higher redshift imply a luminosity-weighted age threshold of ∼3 Gyr

  16. Long-term effects of growth hormone (GH) treatment on body composition and bone mineral density in short children born small-for-gestational-age : six-year follow-up of a randomized controlled GH trial

    NARCIS (Netherlands)

    Willemsen, Ruben H.; Arends, Nicolette J. T.; Waarde, Willie M. Bakker-van; Jansen, Maarten; van Mil, Edgar G. A. H.; Mulder, Jaap; Odink, Roelof J.; Reeser, Maarten; Rongen-Westerlaken, Ciska; Stokvis-Brantsma, Wilhelmina H.; Waelkens, Johan J. J.; Hokken-Koelega, Anita C. S.

    2007-01-01

    Context Alterations in the GH-IGF-I axis in short small-for-gestational-age (SGA) children might be associated with abnormalities in bone mineral density (BMD) and body composition. In addition, birth weight has been inversely associated with diabetes and cardiovascular disease in adult life. Data

  17. Re-Os, Sm-Nd, U-Pb, and stepwise lead leaching isotope systematics in shear-zone hosted gold mineralization: genetic tracing and age constraints of crustal hydrothermal activity

    Science.gov (United States)

    Frei, R.; Nägler, Th. F.; Schönberg, R.; Kramers, J. D.

    1998-06-01

    A combined Re-Os, Sm-Nd, U-Pb, and stepwise Pb leaching (PbSL) isotope study of hydrothermal (Mo-W)-bearing minerals and base metal sulfides from two adjacent shear zone hosted gold deposits (RAN, Kimberley) in the Harare-Shamva greenstone belt (Zimbabwe) constrain the timing of the mineralizing events to two periods. During an initial Late Archean event (2.60 Ga) a first molybdenite-scheelite bearing paragenesis was deposited in both shear zone systems, followed by a local reactivation of the shear systems during an Early Proterozoic (1.96 Ga) tectono-thermal overprint, during which base metal sulfides and most of the gold was (re-)deposited. While PbSL has revealed an open-system behavior of the U-Pb systematics in molybdenite and wolframite from the RAN mine, initial Archean Re-Os ages are still preserved implying that this system in these minerals was more resistant to the overprint. A similar retentivity could be shown for the Sm-Nd system in scheelite and powellite associated with the above ore minerals. Re-Os isotopic data from the Proterozoic mineralization in the Kimberley mine point to a recent gain of Re, most pronouncedly affecting Fe-rich sulfides such as pyrrhotite. A significant Re-loss in powellitic scheelite (an alteration phase of molybdenite-bearing scheelite), coupled with a marked loss of U in W-Mo ore minerals, complements the observation of a major Re uptake in Fe-sulfides during oxidizing conditions in a weathering environment. Pyrrhotite under these conditions behaves as an efficient Re-sink. Lead isotope signatures from PbSL residues of molybdenite, powellite, and quartz indicate a continental crustal source and/or contamination for the mineralizing fluid by interaction of the fluids with older sedimentary material as represented by the direct host country rocks. Our investigation reveals the potential of the Re-Os isotopic system applied to crustal hydrothermal ore minerals for genetic tracing and dating purposes. The simplified chemical

  18. Dietary patterns in Canadian men and women ages 25 and older: relationship to demographics, body mass index, and bone mineral density

    Directory of Open Access Journals (Sweden)

    Towheed Tanveer

    2010-01-01

    Full Text Available Abstract Background Previous research has shown that underlying dietary patterns are related to the risk of many different adverse health outcomes, but the relationship of these underlying patterns to skeletal fragility is not well understood. The objective of the study was to determine whether dietary patterns in men (ages 25-49, 50+ and women (pre-menopause, post-menopause are related to femoral neck bone mineral density (BMD independently of other lifestyle variables, and whether this relationship is mediated by body mass index. Methods We performed an analysis of 1928 men and 4611 women participants in the Canadian Multicentre Osteoporosis Study, a randomly selected population-based longitudinal cohort. We determined dietary patterns based on the self-administered food frequency questionnaires in year 2 of the study (1997-99. Our primary outcome was BMD as measured by dual x-ray absorptiometry in year 5 of the study (2000-02. Results We identified two underlying dietary patterns using factor analysis and then derived factor scores. The first factor (nutrient dense was most strongly associated with intake of fruits, vegetables, and whole grains. The second factor (energy dense was most strongly associated with intake of soft drinks, potato chips and French fries, certain meats (hamburger, hot dog, lunch meat, bacon, and sausage, and certain desserts (doughnuts, chocolate, ice cream. The energy dense factor was associated with higher body mass index independent of other demographic and lifestyle factors, and body mass index was a strong independent predictor of BMD. Surprisingly, we did not find a similar positive association between diet and BMD. In fact, when adjusted for body mass index, each standard deviation increase in the energy dense score was associated with a BMD decrease of 0.009 (95% CI: 0.002, 0.016 g/cm2 for men 50+ years old and 0.004 (95% CI: 0.000, 0.008 g/cm2 for postmenopausal women. In contrast, for men 25-49 years old

  19. Effects of soil water decline on diurnal and seasonal variations in sap flux density for differently aged Japanese cypress (Chamaecyparis obtusa trees

    Directory of Open Access Journals (Sweden)

    Kenji Tsuruta

    2014-01-01

    Full Text Available The effects of soil drought on transpiration are often neglected when predicting transpiration for forests in humid regions under the influence of the Asian monsoon. These effects have indeed been neglected for Japanese cypress, Chamaecyparis obtusa, a major plantation species in Japan and the surrounding area, probably because previous studies have reported no clear effects of soil drought on transpiration for Japanese cypress forests. However, a few studies have reported an apparent reduction in transpiration with soil drought for young Japanese cypress forests. It remains unclear whether such a reduction in transpiration is limited to young Japanese cypress forests or if it is not uncommon for mature Japanese cypress forests, which occupy a large area in Japan. To clarify this point, we conducted sap flux measurements in a year with soil drought on three differently aged Japanese cypress stands including mature (43 years old and relatively young (23 and 26 years old trees. In a diurnal time scale, a cross correlation analysis of sap flux density (Fd and vapor pressure deficit (VPD showed that the time lags between Fd and VPD were 1-3 h in dry soil conditions. These were larger than those of wet soil conditions (<1 h for all sample trees. Fd at a given VPD in dry soil conditions was smaller than that in wet soil conditions for all sample trees; a 28%–63% reduction in the rate of change in Fd was observed under dry soil conditions. Because our results were obtained when the non-exceedance probability of recorded monthly precipitation was 9%–18%, the results suggest the need to consider the effects of soil drought more extensively. Those effects should be considered for not only relatively young but also mature Japanese cypress when predicting diurnal and seasonal patterns of transpiration in years with soil drought, and when predicting inter-annual patterns of transpiration for Japanese cypress despite humid

  20. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  1. THE MASS DEPENDENCE BETWEEN PROTOPLANETARY DISKS AND THEIR STELLAR HOSTS

    International Nuclear Information System (INIS)

    Andrews, Sean M.; Rosenfeld, Katherine A.; Kraus, Adam L.; Wilner, David J.

    2013-01-01

    We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new ''snapshot'' λ = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(L mm ), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3σ depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between L mm and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between L mm and the disk mass, M d , we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of ∼25 mJy for 1 M ☉ hosts and a power-law scaling L mm ∝M * 1.5-2.0 . We suggest that a reasonable treatment of dust temperature in the conversion from L mm to M d favors an inherently linear M d ∝M * scaling, with a typical disk-to-star mass ratio of ∼0.2%-0.6%. The measured rms dispersion around this regression curve is ±0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of ∼40 on the inferred M d (or L mm ) at any given host mass. We argue that this relationship between M d and M * likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the

  2. The Mass Dependence between Protoplanetary Disks and their Stellar Hosts

    Science.gov (United States)

    Andrews, Sean M.; Rosenfeld, Katherine A.; Kraus, Adam L.; Wilner, David J.

    2013-07-01

    We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new "snapshot" λ = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(L mm), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3σ depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between L mm and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between L mm and the disk mass, Md , we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of ~25 mJy for 1 M ⊙ hosts and a power-law scaling L_mm ∝ M_{\\ast}^{1.5-2.0}. We suggest that a reasonable treatment of dust temperature in the conversion from L mm to Md favors an inherently linear Md vpropM * scaling, with a typical disk-to-star mass ratio of ~0.2%-0.6%. The measured rms dispersion around this regression curve is ±0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of ~40 on the inferred Md (or L mm) at any given host mass. We argue that this relationship between Md and M * likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the exoplanet

  3. Age-Related Shifts in the Density and Distribution of Genetic Marker Water Quality Indicators in Cow and Calf Feces (Journal)

    Science.gov (United States)

    Calves (≤ 226 kg body mass) make up about 16% of the current bovine population in the United States and can excrete high levels of human pathogens. We describe the density and distribution of genetic markers from 11 PCR- and real-time quantitative PCR-based assays including CF...

  4. Bone mineral density among systemic lupus erythematosus patient age 5-18 years with glucocorticoid treatment in child and adolescent outpatient clinic, Cipto Mangunkusumo Hospital, Jakarta

    Science.gov (United States)

    Indriyani, N.; Tridjaja, B.; Medise, B. E.; Kurniati, N.

    2017-08-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease affecting children; its morbidity and mortality rates are significant. One risk factor for morbidity is chronic corticosteroid use. The aim of this study is to determine the occurrence rate of low bone mineral density; discuss the characteristics, including cumulative and daily doses of corticosteroid, body mass index, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), calcium, and vitamin D intake; and assess bone metabolism laboratory parameters, including serum calcium, vitamin D, alkaline phosphatase (ALP), phosphorus, and cortisol among children with SLE receiving corticosteroids. This was a descriptive, cross-sectional study involving 16 children with SLE attending the child and adolescent outpatient clinic at Cipto Mangunkusumo Hospital in November-December 2016. Low bone mineral density occurred among 7/16 patients. The mean total bone mineral density was 0.885 ± 0.09 g/cm2. Children with SLE receiving corticosteroid had low calcium (8.69 ± 0.50 mg/dl), vitamin D (19.3 ± 5.4 mg/dl), ALP (79.50 [43.00-164.00] U/l), and morning cortisol level (1.20 [0.0-10.21] ug/dl), as well as calcium (587.58 ± 213.29 mg/d) and vitamin D (2.9 [0-31.8] mcg/d) intake. The occurrence of low bone mineral density was observed among children with SLE receiving corticosteroid treatment. Low bone mineral density tends to occur among patients with higher cumulative doses and longer duration of corticosteroid treatments.

  5. Efficacy of extra corporal shock wave lithotripsy (ESWL) in upper and lower urinary tract calculi with reference to stone site, size shape and radio density according to age rule (abstract)

    International Nuclear Information System (INIS)

    Khan, S.A.; Akhlaq, M.; Ahmed, N.

    1998-01-01

    50 patients having renal ureteral and vesical stones 5-20 mm and having age range 1 years with mean of 30.5 were studied. 70% (35/50) were male and 30% (15/50) female with 2.33:1 ratio 1,1,2,32,10,4 patients were of 0-2, 2-12, 12-18, 18-40, 40-55 and above 55 years age group respectively. Stone site, size, shape and radio density were seen by X-ray plain abdomen, IVU and ultrasound. At 4 months ESWL treatment was considered successful if the patients were stone free or had residual fragments 4 mm or less. Over all success rate was 64% in renal stones it was 62.7% (25/40), in ureteral 62.5% (5/8) and in vesical stone 100% (2/2). 5-10 mm, 11-15 mm and 16-20 mm stones had success rate of 76% (19/25), 61.1% (11/18) and 28.8% (2/7) respectively. Equi bone density, low density, high density and radiolucent stones had success rate of 57.1% (16/28), 92.85% (13/14). 16.6% (1/6) and 100% (2/2). Shape of stones is mere reflection of stone size. In conclusion, the liberal use of ESWL for every type of stone in terms of radio density equal to or less than bone and size up to 20 mm were amenable to ESWL monotherapy. Upper urinary tract stone 96% (48/50) and 18-40 years age group is the commonest. (author)

  6. Feeding guild of non-host community members affects host-foraging efficiency of a parasitic wasp

    NARCIS (Netherlands)

    Rijk, de Marjolein; Yang, Daowei; Engel, Bastiaan; Dicke, Marcel; Poelman, Erik H.

    2016-01-01

    Interactions between predator and prey, or parasitoid and host, are shaped by trait-and density-mediated processes involving other community members. Parasitoids that lay their eggs in herbivorous insects locate their hosts through infochemicals such as herbivore-induced plant volatiles (HIPVs)

  7. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  8. No Effect of Host Species on Phenoloxidase Activity in a Mycophagous Beetle.

    Directory of Open Access Journals (Sweden)

    Vincent Formica

    Full Text Available Ecological immunology is an interdisciplinary field that helps elucidate interactions between the environment and immune response. The host species individuals experience have profound effects on immune response in many species of insects. However, this conclusion comes from studies of herbivorous insects even though species of mycophagous insects also inhabit many different host species. The goal of this study was to determine if fungal host species as well as individual, sex, body size, and host patch predict one aspect of immune function, phenoloxidase activity (PO. We sampled a metapopulation of Bolitotherus cornutus, a mycophagous beetle in southwestern Virginia. B. cornutus live on three species of fungus that differ in nutritional quality, social environment, and density. A filter paper phenoloxidase assay was used to quantify phenoloxidase activity. Overall, PO activity was significantly repeatable among individuals (0.57 in adult B. cornutus. While there was significant variance among individuals in PO activity, there were surprisingly no significant differences in PO activity among subpopulations, beetles living on different host species, or between the sexes; there was also no effect of body size. Our results suggest that other factors such as age, genotype, disease prevalence, or natal environment may be generating variance among individuals in PO activity.

  9. The Intrinsic Characteristics of Galaxies on the SFR–M ∗ Plane at 1.2 < z < 4: I. The Correlation between Stellar Age, Central Density, and Position Relative to the Main Sequence

    Science.gov (United States)

    Lee, Bomee; Giavalisco, Mauro; Whitaker, Katherine; Williams, Christina C.; Ferguson, Henry C.; Acquaviva, Viviana; Koekemoer, Anton M.; Straughn, Amber N.; Guo, Yicheng; Kartaltepe, Jeyhan S.; Lotz, Jennifer; Pacifici, Camilla; Croton, Darren J.; Somerville, Rachel S.; Lu, Yu

    2018-02-01

    We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass (M *), star formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies at 1.2history for each galaxy. Like others, we find that the slope of the main sequence (MS) of star formation in the ({M}* ;{SFR}) plane bends at high mass. We observe clear morphological differences among galaxies across the MS, which also correlate with stellar age. At all redshifts, galaxies that are quenching or quenched, and thus old, have high {{{Σ }}}1 (the projected density within the central 1 kpc), while younger, star-forming galaxies span a much broader range of {{{Σ }}}1, which includes the high values observed for quenched galaxies, but also extends to much lower values. As galaxies age and quench, the stellar age and the dispersion of {{{Σ }}}1 for fixed values of M * shows two different regimes: one at the low-mass end, where quenching might be driven by causes external to the galaxies; the other at the high-mass end, where quenching is driven by internal causes, very likely the mass given the low scatter of {{{Σ }}}1 (mass quenching). We suggest that the monotonic increase of central density as galaxies grow is one manifestation of a more general phenomenon of structural transformation that galaxies undergo as they evolve.

  10. Combined Treatment of Alendronate and Low-Intensity Pulsed Ultrasound (LIPUS Increases Bone Mineral Density at the Cancellous Bone Osteotomy Site in Aged Rats: A Preliminary Study.

    Directory of Open Access Journals (Sweden)

    H Aonuma

    2011-12-01

    Full Text Available Introduction: During fracture healing, alendronate encourages callus volume by inhibiting bone resorption, whereas low-intensity pulsed ultrasound (LIPUS enhances bone regeneration by promoting an anabolic response. Methods: In the present study, 9-month-old Sprague-Dawley rats, with a unilateral proximal tibial osteotomy, were treated with alendronate (daily, 1 g/kg plus sham-LIPUS (n = 14, saline plus LIPUS (20 min/day (n = 18, alendronate plus LIPUS (n = 16, or saline plus sham- LIPUS as a control (n = 13 for 4 weeks. The rats were then examined for changes in bone mineral density (BMD during metaphyseal bone repair. Results: The combined therapy signi cantly increased BMD at the osteotomy site at 4 weeks (p < 0.001 compared with the control, without affecting the contralateral, non-osteotomized tibia. Both alendronate and LIPUS alone also exerted a positive, albeit less, effect on BMD in the affected limb (p < 0.001 and p = 0.006, respectively. Conclusions: Alendronate and LIPUS cooperate to enhance BMD during metaphyseal bone healing. Keywords: LIPUS, bisphosphonate, bone mineral density.

  11. Coat condition of ringtailed lemurs, Lemur catta at Berenty Reserve, Madagascar: I. Differences by age, sex, density and tourism, 1996-2006.

    Science.gov (United States)

    Jolly, Alison

    2009-03-01

    An index of coat condition can be a non-invasive tool for tracking health and stress at population level. Coat condition in ringtailed lemurs, Lemur catta, was recorded during September-November birth seasons of 1996, 1997, 1999, and 2001-2006 at Berenty Reserve, Madagascar. Condition was scored on a scale from 0: full, fluffy coat with guard hairs present, to 5: half or more of body hairless. Adult males did not differ overall from adult females. Coats were worse in adults than in 2-year-old subadults; 1-year-old juveniles were intermediate. Mothers and adult males lost coat condition as the season progressed: non-mother females maintained condition. Years 1999-2002 scored better coats than either 1996-1997 or 2003-2006. Lemurs in high population density areas had worse coats than in natural forest, but tourist presence had less effect than density. Monitoring coat condition in an apparently healthy population reveals differences between population segments, and in a forest fragment with limited immigration or emigration it can track progressive changes, correcting impressions of progressive improvement or degradation over time. Above all it gives a baseline for response to climate changes or eventual pathology. (c) 2008 Wiley-Liss, Inc.

  12. Creating a normative database of age-specific 3D geometrical data, bone density, and bone thickness of the developing skull: a pilot study

    NARCIS (Netherlands)

    Delye, H.H.; Clijmans, T.; Mommaerts, M.Y.; Sloten, J.V.; Goffin, J.

    2015-01-01

    OBJECT Finite element models (FEMs) of the head are used to study the biomechanics of traumatic brain injury and depend heavily on the use of accurate material properties and head geometry. Any FEM aimed at investigating traumatic head injury in children should therefore use age-specific dimensions

  13. A dimensionless ordered pull-through model of the mammalian lens epithelium evidences scaling across species and explains the age-dependent changes in cell density in the human lens

    Science.gov (United States)

    Wu, Jun Jie; Wu, Weiju; Tholozan, Frederique M.; Saunter, Christopher D.; Girkin, John M.; Quinlan, Roy A.

    2015-01-01

    We present a mathematical (ordered pull-through; OPT) model of the cell-density profile for the mammalian lens epithelium together with new experimental data. The model is based upon dimensionless parameters, an important criterion for inter-species comparisons where lens sizes can vary greatly (e.g. bovine (approx. 18 mm); mouse (approx. 2 mm)) and confirms that mammalian lenses scale with size. The validated model includes two parameters: β/α, which is the ratio of the proliferation rate in the peripheral and in the central region of the lens; and γGZ, a dimensionless pull-through parameter that accounts for the cell transition and exit from the epithelium into the lens body. Best-fit values were determined for mouse, rat, rabbit, bovine and human lens epithelia. The OPT model accounts for the peak in cell density at the periphery of the lens epithelium, a region where cell proliferation is concentrated and reaches a maximum coincident with the germinative zone. The β/α ratio correlates with the measured FGF-2 gradient, a morphogen critical to lens cell survival, proliferation and differentiation. As proliferation declines with age, the OPT model predicted age-dependent changes in cell-density profiles, which we observed in mouse and human lenses. PMID:26236824

  14. A MATURE DUSTY STAR-FORMING GALAXY HOSTING GRB 080607 AT z = 3.036

    International Nuclear Information System (INIS)

    Chen, Hsiao-Wen; Perley, Daniel A.; Cenko, S. Bradley; Bloom, Joshua S.; Wilson, Christine D.; Levan, Andrew J.; Prochaska, Jason X.; Tanvir, Nial R.; Dessauges-Zavadsky, Miroslava; Pettini, Max

    2010-01-01

    We report the discovery of the host galaxy of Swift dark burst GRB 080607 at z GRB = 3.036. GRB 080607 is a unique case of a highly extinguished (A V ∼ 3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The host galaxy is clearly resolved in deep Hubble Space Telescope (HST) WF3/IR F160W images and well detected in the Spitzer IRAC 3.5 μm and 4.5 μm channels, while displaying little/no fluxes in deep optical images from Keck and Magellan. The extremely red optical-infrared colors are consistent with the large extinction seen in the afterglow light, suggesting that the large amount of dust and gas surface mass density seen along the afterglow sight line is not merely local but likely reflects the global dust content across the entire host galaxy. Adopting the dust properties and metallicity of the host interstellar medium derived from studies of early-time afterglow light and absorption-line spectroscopy, we perform a stellar population synthesis analysis of the observed spectral energy distribution to constrain the intrinsic luminosity and stellar population of this dark burst host. The host galaxy is best described by an exponentially declining star formation rate of e-folding time τ = 2 Gyr and an age of ∼2 Gyr. We also derive an extinction-corrected star formation rate of SFR ∼ 125 h -2 M sun yr -1 and a total stellar mass of M * ∼ 4 x 10 11 h -2 M sun . Our study provides an example of massive, dusty star-forming galaxies contributing to the γ-ray burst (GRB) host galaxy population, supporting the notion that long-duration GRBs trace the bulk of cosmic star formation.

  15. Effect of Age of Self-Reported, Non-Surgical Menopause on Time to First Fracture and Bone Mineral Density in the Women’s Health Initiative Observational Study

    Science.gov (United States)

    Lehman, Amy; Thomas, Fridtjof; Johnson, Karen C.; Jackson, Rebecca; Wactawski-Wende, Jean; Ko, Marcia; Chen, Zhao; Curb, J David; Howard, Barbara V.

    2015-01-01

    Objective Menopause is a risk factor for fracture, thus menopause age may affect bone mass and fracture rates. We compared Bone Mineral Density (BMD) and fracture rates among healthy postmenopausal women with varying ages of self-reported non-surgical menopause. Methods Hazard ratios for fracture and differences in BMD among 21,711 postmenopausal women from the Women’s Health Initiative Observational cohort without prior hysterectomy, oophorectomy, or hormone therapy, who reported age of menopause of menopausal age groups. After multivariable adjustments for known risk factors for fracture, women undergoing menopause menopause ≥50 years (HR=1.21, 95% CI: 1.02, 1.44; p=0.03). In a subset with BMD measurements (n=1,351), whole body BMD was lower in women who reported menopause menopause menopause menopause age may be a risk factor contributing to decreased BMD and increased fracture risk in healthy postmenopausal women. Our data suggest that menopause age should be taken into consideration, along with other osteoporotic risk factors, when estimating fracture risk in postmenopausal women. PMID:25803670

  16. Study of GRBs Hosts Galaxies Vicinity Properties

    Science.gov (United States)

    Bernal, S.; Vasquez, N.; Hoyle, F.

    2017-07-01

    The study of GRBs host galaxies and its vicinity could provide constrains on the progenitor and an opportunity to use these violent explosions to characterize the nature of the highredshift universe. Studies of GRB host galaxies reveal a population of starforming galaxies with great diversity, spanning a wide range of masses, star formation rate, and redshifts. In order to study the galactic ambient of GRBs we used the S. Savaglio catalog from 2015 where 245 GRBs are listed with RA-Dec position and z. We choose 22 GRBs Hosts galaxies from Savaglio catalog and SDSS DR12, with z range 0population characteristics. We calculate the volumetric density populatation of glalaxies around the GRB Hosts within a volume of an sphere whit radius of 10 h-1 Mpc and find a low density compared with a typical group of galaxies. In order to know the galaxies stellar formation state, in regions where GRBs are formed, we made an analysis of color index using SDSS data of μ [λ 3543], r[λ 6231] and calculate the indexes μ-r. We find a value μ-r=2.63, it means that the galactic ambient of GRBs Host regions are statistically redder than void and wall regions on a indirect way (Voids:μ-r=2.043; Walls:μ-r=2.162). Futhermore, we used a inverse concentration index analysis, ICI=R50/R90 and find that galaxies in GRBs Hosts vicinity are also of slightly early type than void and wall galaxies. With this work we provide characteristics on the regions for future works related with highredsift universe that using the GRBs.

  17. SIDE TO SIDE DIFFERENCES BETWEEN DOMINANT AND NON-DOMINANT ARM’S BONE DENSITY AND ISOMETRIC HANDGRIP STRENGTH IN MALES AND FEMALES AGED 40-65 YEARS OLD

    Science.gov (United States)

    Krasniqi, Ermira; Koni, Mynyr; Kabashi, Antigona; Bahtiri, Abedin; Gjeli, Selda; Boshnjaku, Arben

    2016-01-01

    Objective: This observational, cross-sectional study, investigates and compares the differences of BMD, T-score, Z-score and isometric strength between dominant (D) versus non-dominant (ND) arms of 162 subjects aged 40-65 in a developing, low income country (Kosova). Material and Methods: Bone Mineral Density (BMD), T-score and Z-score at distal forearm regions of both arms (measured by DXA scan), together with the Handgrip Isometric Strength (HIS) (by handgrip) were evaluated in a total subjects (53 Males and 109 Females). Additionally, General Healthcare Status Questionnaire together with self-administrated International Physical Activity Questionnaire (IPAQ) were filled. Results: Significant differences (p0.05) were observed in Males BMD comparing to significantly higher results (p0.05) in males. When comparing the total subject’s BMD, T-score, Z-score and Handgrip based on the PA levels (1 to 3 according to IPAQ scoring) no significant differences (p>0.05) were found between PA1, as well as PA3 whereas significantly differences (p<0.05) were found in D arms of PA2 level. Conclusion: The study analyses side-to-side differences in bone density and muscular force between D and ND arms amongst a population which is frequently exposed to diagnostic screenings for age related osteomuscular conditions (aged 40-60), and demonstrates that these differences should be in consideration amongst clinicians, but not in the way it is done right now. PMID:27999479

  18. Calcium intake and osteoporosis: the influence of calcium intake from dairy products on hip bone mineral density and fracture incidence - a population-based study in women over 55 years of age.

    Science.gov (United States)

    Włodarek, Dariusz; Głąbska, Dominika; Kołota, Aleksandra; Adamczyk, Piotr; Czekajło, Aleksandra; Grzeszczak, Władysław; Drozdzowska, Bogna; Pluskiewicz, Wojciech

    2014-02-01

    The incidence of osteoporosis increases with age and is most frequently observed in postmenopausal women. The objective of the present population-based cohort study was to assess the influence of Ca intake from dairy sources on hip bone mineral density and hip fracture incidence in a group of Polish women over 55 years of age. The main outcome measures included: bone mineral density, the number of previous fractures and the reported Ca intake from dairy sources, assessed by a diet questionnaire. The RAC-OST-POL Study was conducted in the District of Raciborz in the south of Poland. The study was carried out in a group of 625 women, randomly recruited from the general population of women aged >55 years. Median Ca intake from dairy products was lower in the group of women with femoral neck T-score ≤-2·5 than in the group with T-score >-2·5 (275 v. 383 mg/d; P = 0·0019). For total hip score, the difference was close to borderline significance (P = 0·0698). Median Ca intake from dairy products was lower in the group of women with previous fractures than in those without fracture history (336 v. 395 mg/d; P = 0·0254). The main dairy source of Ca in the analysed group included milk drinks, rennet cheese and milk. Higher dairy Ca intake is recommended, since a number of the women analysed were unable to satisfy their Ca requirement exclusively from their diet.

  19. Low Bone Density

    Science.gov (United States)

    ... Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone density ... people with normal bone density. Detecting Low Bone Density A bone density test will determine whether you ...

  20. Late effects of radiation: host factors

    International Nuclear Information System (INIS)

    Fry, R.J.M.; Storer, J.B.

    1983-01-01

    The paper discusses the influence of host factors on radiation late effects and in particular cancer. Radiation induces cellular changes that result in initiated cells with a potential to become cancers. The expression of the initiated cells as tumors is influenced, if not determined, by both tissue and systemic factors that are sex-, age-, and species-dependent

  1. Age-related changes in prefrontal norepinephrine transporter density: The basis for improved cognitive flexibility after low doses of atomoxetine in adolescent rats

    Science.gov (United States)

    Bradshaw, Sarah E.; Agster, Kara L.; Waterhouse, Barry D.; McGaughy, Jill A.

    2016-01-01

    Adolescence is a period of major behavioral and brain reorganization. As diagnoses and treatment of disorders like attention deficit hyperactivity disorder (ADHD) often occur during adolescence, it is important to understand how the prefrontal cortices change and how these changes may influence the response to drugs during development. The current study uses an adolescent rat model to study the effect of standard ADHD treatments, atomoxetine and methylphenidate on attentional set shifting and reversal learning. While both of these drugs act as norepinephrine reuptake inhibitors, higher doses of atomoxetine and all doses of methylphenidate also block dopamine transporters (DAT). Low doses of atomoxetine, were effective at remediating cognitive rigidity found in adolescents. In contrast, methylphenidate improved performance in rats unable to form an attentional set due to distractibility but was without effect in normal subjects. We also assessed the effects of GBR 12909, a selective DAT inhibitor, but found no effect of any dose on behavior. A second study in adolescent rats investigated changes in norepinephrine transporter (NET) and dopamine beta hydroxylase (DBH) density in five functionally distinct subregions of the prefrontal cortex: infralimbic, prelimbic, anterior cingulate, medial and lateral orbitofrontal cortices. These regions are implicated in impulsivity and distractibility. We found that NET, but not DBH, changed across adolescence in a regionally selective manner. The prelimbic cortex, which is critical to cognitive rigidity, and the lateral orbitofrontal cortex, critical to reversal learning and some forms of response inhibition, showed higher levels of NET at early than mid- to late adolescence. PMID:26774596

  2. A prominent large high-density lipoprotein at birth enriched in apolipoprotein C-I identifies a new group of infancts of lower birth weight and younger gestational age

    Energy Technology Data Exchange (ETDEWEB)

    Kwiterovich Jr., Peter O.; Cockrill, Steven L.; Virgil, Donna G.; Garrett, Elizabeth; Otvos, James; Knight-Gibson, Carolyn; Alaupovic, Petar; Forte, Trudy; Farwig, Zachlyn N.; Macfarlane, Ronald D.

    2003-10-01

    Because low birth weight is associated with adverse cardiovascular risk and death in adults, lipoprotein heterogeneity at birth was studied. A prominent, large high-density lipoprotein (HDL) subclass enriched in apolipoprotein C-I (apoC-I) was found in 19 percent of infants, who had significantly lower birth weights and younger gestational ages and distinctly different lipoprotein profiles than infants with undetectable, possible or probable amounts of apoC-I-enriched HDL. An elevated amount of an apoC-I-enriched HDL identifies a new group of low birth weight infants.

  3. Host phylogeny determines viral persistence and replication in novel hosts.

    Directory of Open Access Journals (Sweden)

    Ben Longdon

    2011-09-01

    Full Text Available Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts.

  4. Host Phylogeny Determines Viral Persistence and Replication in Novel Hosts

    Science.gov (United States)

    Longdon, Ben; Hadfield, Jarrod D.; Webster, Claire L.

    2011-01-01

    Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae) to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts. PMID:21966271

  5. A spatial model of mosquito host-seeking behavior.

    Directory of Open Access Journals (Sweden)

    Bree Cummins

    Full Text Available Mosquito host-seeking behavior and heterogeneity in host distribution are important factors in predicting the transmission dynamics of mosquito-borne infections such as dengue fever, malaria, chikungunya, and West Nile virus. We develop and analyze a new mathematical model to describe the effect of spatial heterogeneity on the contact rate between mosquito vectors and hosts. The model includes odor plumes generated by spatially distributed hosts, wind velocity, and mosquito behavior based on both the prevailing wind and the odor plume. On a spatial scale of meters and a time scale of minutes, we compare the effectiveness of different plume-finding and plume-tracking strategies that mosquitoes could use to locate a host. The results show that two different models of chemotaxis are capable of producing comparable results given appropriate parameter choices and that host finding is optimized by a strategy of flying across the wind until the odor plume is intercepted. We also assess the impact of changing the level of host aggregation on mosquito host-finding success near the end of the host-seeking flight. When clusters of hosts are more tightly associated on smaller patches, the odor plume is narrower and the biting rate per host is decreased. For two host groups of unequal number but equal spatial density, the biting rate per host is lower in the group with more individuals, indicative of an attack abatement effect of host aggregation. We discuss how this approach could assist parameter choices in compartmental models that do not explicitly model the spatial arrangement of individuals and how the model could address larger spatial scales and other probability models for mosquito behavior, such as Lévy distributions.

  6. Statistical Properties of Gamma-Ray Burst Host Galaxies Jie-Min ...

    Indian Academy of Sciences (India)

    Statistical Properties of Gamma-Ray Burst Host Galaxies. Jie-Min Chen1, Jin Zhang2,3, ... of GRB host galaxies and explore possible correlations between these properties. We also investigate possible cosmic ... hydrogen column density for the GRB host galaxies in our sample. 6.295. The stellar masses are mainly in the ...

  7. Light emission mechanism of mixed host organic light-emitting diodes

    Science.gov (United States)

    Song, Wook; Lee, Jun Yeob

    2015-03-01

    Light emission mechanism of organic light-emitting diodes with a mixed host emitting layer was studied using an exciplex type mixed host and an exciplex free mixed host. Monitoring of the current density and luminance of the two type mixed host devices revealed that the light emission process of the exciplex type mixed host was dominated by energy transfer, while the light emission of the exciplex free mixed host was controlled by charge trapping. Mixed host composition was also critical to the light emission mechanism, and the contribution of the energy transfer process was maximized at 50:50 mixed host composition. Therefore, it was possible to manage the light emission process of the mixed host devices by managing the mixed host composition.

  8. Level densities

    International Nuclear Information System (INIS)

    Ignatyuk, A.V.

    1998-01-01

    For any applications of the statistical theory of nuclear reactions it is very important to obtain the parameters of the level density description from the reliable experimental data. The cumulative numbers of low-lying levels and the average spacings between neutron resonances are usually used as such data. The level density parameters fitted to such data are compiled in the RIPL Starter File for the tree models most frequently used in practical calculations: i) For the Gilber-Cameron model the parameters of the Beijing group, based on a rather recent compilations of the neutron resonance and low-lying level densities and included into the beijing-gc.dat file, are chosen as recommended. As alternative versions the parameters provided by other groups are given into the files: jaeri-gc.dat, bombay-gc.dat, obninsk-gc.dat. Additionally the iljinov-gc.dat, and mengoni-gc.dat files include sets of the level density parameters that take into account the damping of shell effects at high energies. ii) For the backed-shifted Fermi gas model the beijing-bs.dat file is selected as the recommended one. Alternative parameters of the Obninsk group are given in the obninsk-bs.dat file and those of Bombay in bombay-bs.dat. iii) For the generalized superfluid model the Obninsk group parameters included into the obninsk-bcs.dat file are chosen as recommended ones and the beijing-bcs.dat file is included as an alternative set of parameters. iv) For the microscopic approach to the level densities the files are: obninsk-micro.for -FORTRAN 77 source for the microscopical statistical level density code developed in Obninsk by Ignatyuk and coworkers, moller-levels.gz - Moeller single-particle level and ground state deformation data base, moller-levels.for -retrieval code for Moeller single-particle level scheme. (author)

  9. The path to host extinction can lead to loss of generalist parasites.

    Science.gov (United States)

    Farrell, Maxwell J; Stephens, Patrick R; Berrang-Ford, Lea; Gittleman, John L; Davies, T Jonathan

    2015-07-01

    Host extinction can alter disease transmission dynamics, influence parasite extinction and ultimately change the nature of host-parasite systems. While theory predicts that single-host parasites are among the parasite species most susceptible to extinction following declines in their hosts, documented parasite extinctions are rare. Using a comparative approach, we investigate how the richness of single-host and multi-host parasites is influenced by extinction risk among ungulate and carnivore hosts. Host-parasite associations for free-living carnivores (order Carnivora) and terrestrial ungulates (orders Perissodactyla + Cetartiodactyla minus cetaceans) were merged with host trait data and IUCN Red List status to explore the distribution of single-host and multi-host parasites among threatened and non-threatened hosts. We find that threatened ungulates harbour a higher proportion of single-host parasites compared to non-threatened ungulates, which is explained by decreases in the richness of multi-host parasites. However, among carnivores threat status is not a significant predictor of the proportion of single-host parasites, or the richness of single-host or multi-host parasites. The loss of multi-host parasites from threatened ungulates may be explained by decreased cross-species contact as hosts decline and habitats become fragmented. Among carnivores, threat status may not be important in predicting patterns of parasite specificity because host decline results in equal losses of both single-host parasites and multi-host parasites through reduction in average population density and frequency of cross-species contact. Our results contrast with current models of parasite coextinction and highlight the need for updated theories that are applicable across host groups and account for both inter- and intraspecific contact. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  10. Effect of insulin combined alendronate sodium on bone mineral density and levels of serum BAP, TRAP-5b and BGP in aged patients with type 2 diabetes mellitus with osteoporosis

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2016-06-01

    Full Text Available Objective: To explore the effect of insulin combined alendronate sodium on bone mineral density and levels of serum BAP, TRAP-5b and BGP in aged patients with type 2 diabetes mellitus with osteoporosis. Methods: A total of 136 patients with type 2 diabetes mellitus with osteoporosis in January 2014 to January 2016 in our hospital for the treatment were selected, and randomly divided into 4 groups, each of 40 cases. Caltrate D was given as a basic treatment to all the patients, and the control group was given the treatment of insulin, and the metformin group was given the treatment of metformin, and the combination group was given the treatment of metformin combined alendronate, and the experiment group was given the treatment of insulin combined alendronate. BMD of the femoral neck and the serum levels of BAP, TRAP-5b and BGP were detected and recorded before the treatment and after one year’s treatment. Results: On index of bone mineral density, the control group and the metformin group showed no significant differences; the combination group was slightly improved, but showed no statistical significance; After the treatment, the bone mineral density of the experiment was significantly improved. On index of bone turnover, the levels of serum BAP and BGP all had been improved and the level of TRAP-5b all was reduced then before the treatment in the control group, the combination group and the experiment group, but only the experiment group showed significant differences; On index of bone turnover, the experiment group were better than other groups, the differences were statistical significant. Conclusions: It has greater clinical curative effect that insulin combined alendronate sodium in the treatment of aged patients with type 2 diabetes mellitus with osteoporosis, it can effectively balance the metabolism of bone, safe and reliable, and it is worthy of application.

  11. APP with Kunitz type protease inhibitor domain (KPI) correlates with neuritic plaque density but not with cortical synaptophysin immunoreactivity in Alzheimer's disease and non-demented aged subjects: a multifactorial analysis.

    Science.gov (United States)

    Zhan, S S; Sandbrink, R; Beyreuther, K; Schmitt, H P

    1995-01-01

    The formation of beta A4 amyloid protein in neuritic plaques in Alzheimer's disease (AD) and advanced age is a complex process that involves a number of both cellular and molecular mechanisms, the interrelations of which are not yet completely understood. We have examined quantitatively, in AD and aged controls an extended spectrum of amyloid plaque-related cellular and molecular factors and the cortical synaptophysin immunoreactivity (synaptic density) in order to check for interrelations between them by multifactorial analysis. In 3 cases of senile dementia of the Alzheimer type (SDAT) aged 72, 80 and 82 years, and 9 controls aged 43-88 (mean age 65) years, the cortical synaptophysin immunoreactivity was assessed, together with the numbers of neurons, astrocytes and microglial cells, senile plaques, of tangle-bearing neurons, and the amount of beta A4 amyloid precursor protein (APP) with and without the Kunitz type serine protease inhibitor (KPI) domain. The main results were: APP including the KPI domain (KPI-APP) correlated with the number of neuritic plaques, regardless of whether they occurred in SDAT or non-demented controls. There was no significant difference in the amount of KPI-APP between SDAT and controls. Conversely, APP695 (without KPI) was significantly reduced in SDAT. KPI-APP did not correlate with the synaptophysin immunoreactivity (RGVA), while APP695 showed a significant correlation with the latter in all evaluations. It also correlated with the neuron counts, which was not true for KPI-APP. These results support previous findings indicating that KPI-APP is an important local factor for amyloid deposition in the neuritic plaques, both in AD and in non-demented aged people. On the contrary, KPI-APP does not seem to be significantly involved in the mechanisms of synaptic change outside of the plaques.

  12. Slingshot mechanism for clusters: Gas density regulates star density in the Orion Nebula Cluster (M42)

    Science.gov (United States)

    Stutz, Amelia M.

    2018-02-01

    We characterize the stellar and gas volume density, potential, and gravitational field profiles in the central ∼0.5 pc of the Orion Nebula Cluster (ONC), the nearest embedded star cluster (or rather, protocluster) hosting massive star formation available for detailed observational scrutiny. We find that the stellar volume density is well characterized by a Plummer profile ρstars(r) = 5755 M⊙ pc- 3 (1 + (r/a)2)- 5/2, where a = 0.36 pc. The gas density follows a cylindrical power law ρgas(R) = 25.9 M⊙ pc- 3 (R/pc)- 1.775. The stellar density profile dominates over the gas density profile inside r ∼ 1 pc. The gravitational field is gas-dominated at all radii, but the contribution to the total field by the stars is nearly equal to that of the gas at r ∼ a. This fact alone demonstrates that the protocluster cannot be considered a gas-free system or a virialized system dominated by its own gravity. The stellar protocluster core is dynamically young, with an age of ∼2-3 Myr, a 1D velocity dispersion of σobs = 2.6 km s-1, and a crossing time of ∼0.55 Myr. This time-scale is almost identical to the gas filament oscillation time-scale estimated recently by Stutz & Gould. This provides strong evidence that the protocluster structure is regulated by the gas filament. The protocluster structure may be set by tidal forces due to the oscillating filamentary gas potential. Such forces could naturally suppress low density stellar structures on scales ≳ a. The analysis presented here leads to a new suggestion that clusters form by an analogue of the 'slingshot mechanism' previously proposed for stars.

  13. Fatty acid-producing hosts

    Science.gov (United States)

    Pfleger, Brian F; Lennen, Rebecca M

    2013-12-31

    Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

  14. Wolbachia mediate variation of host immunocompetence.

    Directory of Open Access Journals (Sweden)

    Christine Braquart-Varnier

    Full Text Available BACKGROUND: After decades during which endosymbionts were considered as silent in their hosts, in particular concerning the immune system, recent studies have revealed the contrary. In the present paper, we addressed the effect of Wolbachia, the most prevalent endosymbiont in arthropods, on host immunocompetence. To this end, we chose the A. vulgare-Wolbachia symbiosis as a model system because it leads to compare consequences of two Wolbachia strains (wVulC and wVulM on hosts from the same population. Moreover, A. vulgare is the only host-species in which Wolbachia have been directly observed within haemocytes which are responsible for both humoral and cellular immune responses. METHODOLOGY/PRINCIPAL FINDINGS: We sampled gravid females from the same population that were either asymbiotic, infected with wVulC, or infected with wVulM. The offspring from these females were tested and it was revealed that individuals harbouring wVulC exhibited: (i lower haemocyte densities, (ii more intense septicaemia in their haemolymph and (iii a reduced lifespan as compared to individuals habouring wVulM or asymbiotic ones. Therefore, individuals in this population of A. vulgare appeared to suffer more from wVulC than from wVulM. Symbiotic titer and location in the haemocytes did not differ for the two Wolbachia strains showing that these two parameters were not responsible for differences observed in their extended phenotypes in A. vulgare. CONCLUSION/SIGNIFICANCE: The two Wolbachia strains infecting A. vulgare in the same population induced variation in immunocompetence and survival of their hosts. Such variation should highly influence the dynamics of this host-symbiont system. We propose in accordance with previous population genetic works, that wVulM is a local strain that has attenuated its virulence through a long term adaptation process towards local A. vulgare genotypes whereas wVulC, which is a widespread and invasive strain, is not locally adapted.

  15. Cdx-2 polymorphism in Vitamin D Receptor gene was associated with serum 25-hydroxyvitamin D levels, bone mineral density and fracture in middle-aged and elderly Chinese women.

    Science.gov (United States)

    Ling, Yan; Lin, Huandong; Aleteng, Qiqige; Ma, Hui; Pan, Baishen; Gao, Jian; Gao, Xin

    2016-05-15

    The aim of the current study was to examine the relationship between Cdx-2 polymorphism in the promoter region of the VDR gene and serum 25-hydroxyvitamin D (25(OH)D) levels, bone mineral density (BMD) and fracture in Chinese population. This was a cross-sectional study, which included 738 individuals (428 women and 310 men) aged 45 years or older. In women, the association of Cdx-2 polymorphism with serum 25(OH)D levels was significant adjusting for age, BMI, estimated glomerular filtration rate, menopausal status and season of blood collection (P = 0.002). Cdx-2 polymorphism was associated with lumbar spine BMD adjusted for age, BMI, menopausal status and serum 25(OH)D in women (P = 0.005). But it was not associated with femoral neck BMD or total hip BMD in women. In women, Cdx-2 polymorphism was also associated with fracture adjusted for age, BMI, menopausal status, serum 25(OH)D and total hip BMD (P = 0.03). Carriers of AA and AG genotypes was associated with a higher odds of fracture compared with the carriers of GG genotype (OR = 2.14, 95% CI 1.04-4.42 and OR = 1.90, 95% CI 1.03-3.51). In men, Cdx-2 polymorphism was not associated with serum 25(OH)D levels, BMD or fracture. Our results indicate that the association of Cdx-2 polymorphism in the VDR gene with serum 25(OH)D levels, BMD and fracture may have sex differences. Cdx-2 polymorphism in the VDR gene may affect the serum 25(OH)D concentrations and the risk of osteoporosis and fracture in middle-aged and elderly Chinese women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Guidelines for Hosted Payload Integration

    Science.gov (United States)

    2014-06-06

    reduces risk. Need to consider mass simulator to protect host launch window. Average Payload Power Both BOL and EOL . Host must consider orbit...acceptance testing. Peak Payload Power Both BOL and EOL . Host must consider orbit constraints. Typically driven by Payload operations but must...post-retirement failure might cause damage to the Spacecraft Host or its payloads. Safe conditions at EOL should consider thermal and radiation

  17. HostPhinder: A Phage Host Prediction Tool

    Directory of Open Access Journals (Sweden)

    Julia Villarroel

    2016-05-01

    Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

  18. Aged-Related Changes in Body Composition and Association between Body Composition with Bone Mass Density by Body Mass Index in Chinese Han Men over 50-year-old.

    Directory of Open Access Journals (Sweden)

    Ying Jiang

    Full Text Available Aging, body composition, and body mass index (BMI are important factors in bone mineral density (BMD. Although several studies have investigated the various parameters and factors that differentially influence BMD, the results have been inconsistent. Thus, the primary goal of the present study was to further characterize the relationships of aging, body composition parameters, and BMI with BMD in Chinese Han males older than 50 years.The present study was a retrospective analysis of the body composition, BMI, and BMD of 358 Chinese male outpatients between 50 and 89 years of age that were recruited from our hospital between 2009 and 2011. Qualified subjects were stratified according to age and BMI as follows: 50-59 (n = 35, 60-69 (n = 123, 70-79 (n = 93, and 80-89 (n = 107 years of age and low weight (BMI: < 20 kg/m2; n = 21, medium weight (20 ≤ BMI < 24 kg/m2; n = 118, overweight (24 ≤ BMI < 28 kg/m2; n = 178, and obese (BMI ≥ 28 kg/m2; n = 41. Dual-energy X-ray absorptiometry (DEXA was used to assess bone mineral content (BMC, lean mass (LM, fat mass (FM, fat-free mass (FFM, lumbar spine (L1-L4 BMD, femoral neck BMD, and total hip BMD. Additionally, the FM index (FMI; FM/height2, LM index (LMI; LM/height2, FFM index (FFMI; [BMC+LM]/height2, percentage of BMC (%BMC; BMC/[BMC+FM+LM] × 100%, percentage of FM (%FM; FM/[BMC+FM+LM] × 100%, and percentage of LM (%LM; LM/(BMC+FM+LM × 100% were calculated. Osteopenia or osteoporosis was identified using the criteria and T-score of the World Health Organization.Although there were no significant differences in BMI among the age groups, there was a significant decline in height and weight according to age (p < 0.0001 and p = 0.0002, respectively. The LMI and FFMI also declined with age (both p < 0.0001 whereas the FMI exhibited a significant increase that peaked in the 80-89-years group (p = 0.0145. Although the absolute values of BMC and LM declined with age (p = 0.0031 and p < 0

  19. Body fat mass, lean body mass and associated biomarkers as determinants of bone mineral density in children 6-8years of age - The Physical Activity and Nutrition in Children (PANIC) study.

    Science.gov (United States)

    Soininen, Sonja; Sidoroff, Virpi; Lindi, Virpi; Mahonen, Anitta; Kröger, Liisa; Kröger, Heikki; Jääskeläinen, Jarmo; Atalay, Mustafa; Laaksonen, David E; Laitinen, Tomi; Lakka, Timo A

    2018-03-01

    Lean body mass (LM) has been positively associated with bone mineral density (BMD) in children and adolescents, but the relationship between body fat mass (FM) and BMD remains controversial. Several biomarkers secreted by adipose tissue, skeletal muscle, or bone may affect bone metabolism and BMD. We investigated the associations of LM, FM, and such biomarkers with BMD in children. We studied a population sample of 472 prepubertal Finnish children (227 girls, 245 boys) aged 6-8years. We assessed BMD, LM, and FM using whole-body dual-energy x-ray absorptiometry and analysed several biomarkers from fasting blood samples. We studied the associations of LM, FM, and the biomarkers with BMD of the whole body excluding the head using linear regression analysis. LM (standardized regression coefficient β=0.708, p<0.001), FM (β=0.358, p<0.001), and irisin (β=0.079, p=0.048) were positive correlates for BMD adjusted for age, sex, and height in all children. These associations remained statistically significant after further adjustment for LM or FM. The positive associations of dehydroepiandrosterone sulphate (DHEAS), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), leptin, free leptin index, and high-sensitivity C-reactive protein and the negative association of leptin receptor with BMD were explained by FM. The positive associations of DHEAS and HOMA-IR with BMD were also explained by LM. Serum 25-hydroxyvitamin D was a positive correlate for BMD adjusted for age, sex, and height and after further adjustment for FM but not for LM. LM and FM were positive correlates for BMD also in girls and boys separately. In girls, insulin, HOMA-IR, leptin, and free leptin index were positively and leptin receptor was negatively associated with BMD adjusted for age, height, and LM. After adjustment for age, height, and FM, none of the biomarkers was associated with BMD. In boys, leptin and free leptin index were positively and leptin receptor was negatively

  20. Predictors of optical density of lutein and zeaxanthin in retinas of older women in the Carotenoids in Age-Related Eye Disease Study, an ancillary study of the Women's Health Initiative.

    Science.gov (United States)

    Mares, Julie A; LaRowe, Tara L; Snodderly, D Max; Moeller, Suzen M; Gruber, Michael J; Klein, Michael L; Wooten, Billy R; Johnson, Elizabeth J; Chappell, Richard J

    2006-11-01

    Lifestyle, diet, and physical and health predictors of xanthophyll carotenoids in the retina are poorly understood. We aimed to investigate the predictors of the density of lutein and zeaxanthin in the macula of the retina. Macular pigment optical density (MPOD) was measured by heterochromatic flicker photometry. Relations to dietary lutein and zeaxanthin and to other predictors were measured in 1698 women aged 53-86 y. The women were members of observational study cohorts of the Women's Health Initiative at Iowa City, IA, Madison, WI, or Portland, OR, and participated in the Carotenoids in Age-Related Eye Disease Study (2001-2004). MPOD at 0.5 degrees from the foveal center was 30% higher in women in the highest quintile for lutein and zeaxanthin intake [x (+/-SD): 0.40 +/- 0.21] than in women in the lowest quintile (0.31 +/- 0.21) and 20% higher after adjustment for other predictors. Dietary intake of lutein, zeaxanthin, fiber, and polyunsaturated fatty acids (% of energy) together explained 3% of the variability in MPOD. Higher waist circumference and diabetes, which are related to lower MPOD, together with study site explained an additional 5% of variation. The total explained variability increased to 12% when lutein and zexanthin concentrations obtained from the serum, which were collected 4-7 y earlier, were added to the model. MPOD is directly related to dietary intake of lutein and zeaxanthin but even more strongly to serum concentrations, which may reflect unmeasured physical and medical factors that influence the uptake, distribution, and utilization of lutein and zeaxanthin. Higher abdominal body fat and diabetes are related to lower MPOD. Unknown predictors of retinal carotenoids remain.

  1. Mid-life environmental enrichment increases synaptic density in CA1 in a mouse model of Aβ-associated pathology and positively influences synaptic and cognitive health in healthy ageing.

    Science.gov (United States)

    Stuart, Kimberley E; King, Anna E; Fernandez-Martos, Carmen M; Dittmann, Justin; Summers, Mathew J; Vickers, James C

    2017-06-01

    Early-life cognitive enrichment may reduce the risk of experiencing cognitive deterioration and dementia in later-life. However, an intervention to prevent or delay dementia is likely to be taken up in mid to later-life. Hence, we investigated the effects of environmental enrichment in wildtype mice and in a mouse model of Aβ neuropathology (APP SWE /PS1 dE9 ) from 6 months of age. After 6 months of housing in standard laboratory cages, APP SWE /PS1 dE9 (n = 27) and healthy wildtype (n = 21) mice were randomly assigned to either enriched or standard housing. At 12 months of age, wildtype mice showed altered synaptic protein levels and relatively superior cognitive performance afforded by environmental enrichment. Environmental enrichment was not associated with alterations to Aβ plaque pathology in the neocortex or hippocampus of APP SWE /PS1 dE9 mice. However, a significant increase in synaptophysin immunolabeled puncta in the hippocampal subregion, CA1, in APP SWE /PS1 dE9 mice was detected, with no significant synaptic density changes observed in CA3, or the Fr2 region of the prefrontal cortex. Moreover, a significant increase in hippocampal BDNF was detected in APP SWE /PS1 dE9 mice exposed to EE, however, no changes were detected in neocortex or between Wt animals. These results demonstrate that mid to later-life cognitive enrichment has the potential to promote synaptic and cognitive health in ageing, and to enhance compensatory capacity for synaptic connectivity in pathological ageing associated with Aβ deposition. © 2017 Wiley Periodicals, Inc.

  2. The Drosophila melanogaster host model

    Science.gov (United States)

    Igboin, Christina O.; Griffen, Ann L.; Leys, Eugene J.

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed. PMID:22368770

  3. The Drosophila melanogaster host model

    Directory of Open Access Journals (Sweden)

    Christina O. Igboin

    2012-02-01

    Full Text Available The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.

  4. The Drosophila melanogaster host model.

    Science.gov (United States)

    Igboin, Christina O; Griffen, Ann L; Leys, Eugene J

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen-host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial-host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis-host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.

  5. Host genetics affect microbial ecosystems via host immunity.

    Science.gov (United States)

    El Kafsi, Hela; Gorochov, Guy; Larsen, Martin

    2016-10-01

    Genetic evolution of multicellular organisms has occurred in response to environmental challenges, including competition for nutrients, climate change, physical and chemical stressors, and pathogens. However, fitness of an organism is dependent not only on defense efficacy, but also on the ability to take advantage of symbiotic organisms. Indeed, microbes not only encompass pathogenicity, but also enable efficient nutrient uptake from diets nondegradable by the host itself. Moreover, microbes play important roles in the development of host immunity. Here we review associations between specific host genes and variance in microbiota composition and compare with interactions between microbes and host immunity. Recent genome-wide association studies reveal that symbiosis between host and microbiota is the exquisite result of genetic coevolution. Moreover, a subset of microbes from human and mouse microbiota have been identified to interact with humoral and cellular immunity. Interestingly, microbes associated with both host genetics and host immunity are taxonomically related. Most involved are Bifidobacterium, Lactobacillus, and Akkermansia, which are dually associated with both host immunity and host genetics. We conclude that future therapeutics targeting microbiota in the context of chronic inflammatory diseases need to consider both immune and genetic host features associated with microbiota homeostasis.

  6. Host Selection Behavior and the Fecundity of Plutella xylostella (Lepidoptera: Plutellidae) on Multiple Host Plants

    Science.gov (United States)

    Huang, Bin; Shi, Zhanghong; Hou, Youming

    2014-01-01

    Abstract Insect herbivores often have higher densities on host plants grown in monocultures than those in diverse environments. The underlying mechanisms are thought to be that polyphagous insects have difficulty in selecting food or oviposition sites when multiple host plants exist. However, this hypothesis needs to be extensively investigated. Our field experiments revealed that the population of the diamondback moths, Plutella xylostella (L.) (Lepidoptera: Plutellidae), significantly decreased in a mixed cropping field compared with a monoculture. To determine the reasons for the reduction in population in the mixed cropping field, the takeoff behavior and fecundity of females in no-choice and free-choice laboratory environments were compared by video recordings of host selection by P. xylostella . Adults displayed a significantly higher takeoff frequency in free-choice environments than those in no-choice treatments and preferred landing on Brassica campestris (L.) or Brassica juncea (Coss) plants in contrast with Brassica oleracea (L.). Female adults in the free-choice environment also laid fewer eggs compared with the monoculture. Olfaction experiments demonstrated orientation by P. xylostella to host volatiles when presented with a choice between plant odors and clean air, but females showed no preference when odors from three Brassicaceae species were presented simultaneously. We conclude that mixed cropping alters the host-finding behavior of P. xylostella resulting in reduced oviposition. PMID:25527573

  7. Factores de riesgo modificables o no, relacionados con la densidad mineral ósea en mujeres de edad mediana Modifiable or not factors related to mineral bone density in middle aged women

    Directory of Open Access Journals (Sweden)

    Cossette Díaz Socorro

    2012-04-01

    ,025, antecedente familiar de fractura (Odds Ratio= 2,836, p= 0,044, y la posmenopausia (Odds Ratio= 10,185, p= 0,008. Conclusiones: las mujeres de edad mediana que presentaron mayor probabilidad de tener una masa ósea disminuida fueron aquellas de color de la piel blanca, con antecedentes familiares de fractura, y en las que la posmenopausia comparece.Introduction: in Cuba there are not national data on the osteoporosis's prevalence. The world demographic changes make necessary the research and the diffusion of information relative to osteoporosis. Objective: to identify the possible differences in the bon mineral density, according to the presence of modifiable or not risk factors in middle aged women. Methods: a cross-sectional and descriptive study was conducted in 259 patients came to ClimOs consultation in the National Institute of Endocrinology ruled out the women presenting with secondary osteoporosis. The bone mineral density is determined by means of dual beam absorptiometry in distal forearm and lumbar spine. Patients were divided into two categories: those with a normal mineral bone density located in I group and those with a low bone mineral density (osteopenia and/or osteoporosis corresponded to II group. To establish differences among groups the t student and chi2 tests with a 5 % significance level. The multiple logistic regression was used for analysis of bone mineral density integrating both study regions. Results: combining the results of the densitometry carried out in th forearm and lumbar spine of the 259 middle aged women, the 72.2 % had a low bone mass including 99 patients (38.2 % with osteopenia and 88 (34.0 % diagnosed with osteoporosis, only 72 (27.8 % women had a normal bone mass. Applying the multiple logistic regression to statistically significant variables: age, skin color, family pathological background of fracture, ovarian function, body mass rate, follicle-stimulating hormone, luteinizing hormone and estradiol, those associated with a great

  8. THE OPTICAL AFTERGLOW AND z = 0.92 EARLY-TYPE HOST GALAXY OF THE SHORT GRB 100117A

    International Nuclear Information System (INIS)

    Fong, W.; Berger, E.; Chornock, R.; Tanvir, N. R.; Levan, A. J.; Fruchter, A. S.; Graham, J. F.; Cucchiara, A.; Fox, D. B.

    2011-01-01

    We present the discovery of the optical afterglow and early-type host galaxy of the short-duration GRB 100117A. The faint afterglow is detected 8.3 hr after the burst with r AB = 25.46 ± 0.20 mag. Follow-up optical and near-infrared observations uncover a coincident compact red galaxy, identified as an early-type galaxy at a spectroscopic redshift of z ∼ 0.915 with a mass of ∼3 x 10 10 M sun , an age of ∼1 Gyr, and a luminosity of L B ≅ 0.5 L * . From a possible weak detection of [O II]λ3727 emission at z = 0.915 we infer an upper bound on the star formation rate of ∼0.1 M sun yr -1 , leading to a specific star formation rate of ∼ -1 . Thus, GRB 100117A is only the second short burst to date with a secure early-type host (the other being GRB 050724 at z = 0.257) and it has one of the highest short gamma-ray burst (GRB) redshifts. The offset between the host center and the burst position, 470 ± 310 pc, is the smallest to date. Combined with the old stellar population age, this indicates that the burst likely originated from a progenitor with no significant kick velocity. However, from the brightness of the optical afterglow we infer a relatively low density of n ∼ 3 x 10 -4 ε -3 e,-1 ε -1.75 B,-1 cm -3 . The combination of an optically faint afterglow and host suggests that previous such events may have been missed, thereby potentially biasing the known short GRB host population against z ∼> 1 early-type hosts.

  9. Serum low-density lipoprotein cholesterol level is strong risk factor for acquired color vision impairment in young to middle-aged Japanese men: the Okubo Color Study Report 2.

    Science.gov (United States)

    Shoji, Takuhei; Sakurai, Yutaka; Sato, Hiroki; Chihara, Etsuo; Ishida, Masahiro; Omae, Kazuyuki

    2010-06-01

    To investigate associations between blood low-density lipoprotein cholesterol (LDL-C) levels and the prevalence of acquired color vision impairment (ACVI) in middle-aged Japanese men. Participants in this cross-sectional study underwent color vision testing, ophthalmic examination, a standardized interview and examination of venous blood samples. Ishihara plates, a Lanthony 15-hue desaturated panel, and Standard pseudoisochromatic Plates part 2 were used to examine color vision ability. The Farnsworth-Munsell 100-hue test was performed to define ACVI. Smoking status and alcohol intake were recorded during the interview. We performed logistic regression analysis adjusted for age, LDL-C level, systemic hypertension, diabetes, cataract, glaucoma, overweight, smoking status, and alcohol intake. Adjusted odds ratios for four LDL-C levels were calculated. A total of 1042 men were enrolled, 872 participants were eligible for the study, and 31 subjects were diagnosed with ACVI. As compared to the lowest LDL-C category level (or=160 mg/dl). The multiple-adjusted ORs were 2.91 (95% CI, 0.87-9.70) for the 2nd highest category and 3.81 (95% CI, 1.03-14.05) for the highest level. Tests for trend were significant (Pmen with elevated LDL-C levels. These changes might be related to deteriorated neurologic function associated with lipid metabolite abnormalities. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  10. Preferência alimentar, efeito da planta hospedeira e da densidade larval na sobrevivência e desenvolvimento de Dione juno juno (Cramer (Lepidoptera, Nymphalidae Feeding preference, host-plant and larval density effects on survivorship and growth rates of Dione juno juno (Cramer (Lepidoptera, Nymphalidae

    Directory of Open Access Journals (Sweden)

    Vidica Bianchi

    2005-03-01

    , 1753; P. capsularis Linnaeus, 1753; P. edulis Sims, 1818; P. elegans Masters, 1872; P. misera Humbold, Bonpland et Kunth, 1817; P. suberosa Linnaeus, 1753; P. tenuifila Killip, 1927 and P. warmingii Masters, 1872. Larval density effect on performance was also tested on P. edulis, by using seven larval group sizes: one, two, eight, sixteen, thirty-two and sixty-four larvae. Larval feeding preferences were evaluated through leaf disk, single and multiple choice tests. Larvae achieved the greatest survivorship on P. misera, P. tenuifila and P. edulis. None survived on P. alata, P. capsularis, P. amesthystina, P. suberosa, and P. warmingii. Larvae chose P. edulis on multiple choice tests. They ingested similar amounts of P. tenuifila, P. misera and P. caerulea on single choice tests. Larval growth rates were greater, and adults were larger when reared on P. misera compared to P. edulis. Survivorship was significantly reduced on group sizes of one, two and four larvae, and thus may account for the larval aggregation behavior on this species. We concluded that a few passion vine species other than P. edulis can act as potential host-plants for D. juno juno in Rio Grande do Sul State. From an ecological perspective, however, most of these alternative host-plant species present limitations regarding either suitability, plant size or abundance.

  11. Host-race formation: promoted by phenology, constrained by heritability.

    Science.gov (United States)

    Whipple, A V; Abrahamson, W G; Khamiss, M A; Heinrich, P L; Urian, A G; Northridge, E M

    2009-04-01

    Host-race formation is promoted by genetic trade-offs in the ability of herbivores to use alternate hosts, including trade-offs due to differential timing of host-plant availability. We examined the role of phenology in limiting host-plant use in the goldenrod gall fly (Eurosta solidaginis) by determining: (1) whether phenology limits alternate host use, leading to a trade-off that could cause divergent selection on Eurosta emergence time and (2) whether Eurosta has the genetic capacity to respond to such selection in the face of existing environmental variation. Experiments demonstrated that oviposition and gall induction on the alternate host, Solidago canadensis, were the highest on young plants, whereas the highest levels of gall induction on the normal host, Solidago gigantea, occurred on intermediate-age plants. These findings indicate a phenological trade-off for host-plant use that sets up the possibility of divergent selection on emergence time. Heritability, estimated by parent-offspring regression, indicated that host-race formation is impeded by the amount of genetic variation, relative to environmental, for emergence time.

  12. Host Factors in Ebola Infection.

    Science.gov (United States)

    Rasmussen, Angela L

    2016-08-31

    Ebola virus (EBOV) emerged in West Africa in 2014 to devastating effect, and demonstrated that infection can cause a broad range of severe disease manifestations. As the virus itself was genetically similar to other Zaire ebolaviruses, the spectrum of pathology likely resulted from variable responses to infection in a large and genetically diverse population. This review comprehensively summarizes current knowledge of the host response to EBOV infection, including pathways hijacked by the virus to facilitate replication, host processes that contribute directly to pathogenesis, and host-pathogen interactions involved in subverting or antagonizing host antiviral immunity.

  13. HostPhinder: A Phage Host Prediction Tool

    DEFF Research Database (Denmark)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within...... bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2]....

  14. HOST liner cyclic facilities

    Science.gov (United States)

    Schultz, D.

    1983-01-01

    The HOST Liner Cyclic Program is utilizing two types of test apparatus, rectangular box rigs and a full annular rig. To date two quartz lamp cyclic box rigs have been tested and a third is to begin testing in late October 1983. The box rigs are used to evaluate 5x8 inch rectangular linear samples. A 21 inch diameter outer liner simulator is also being built up for testing beginning in April 1984. All rigs are atmospheric rigs. The first box rig, a three 6-kVA lamp installation, was operated under adverse conditions to determine feasibility of using quartz lamps for cyclic testing. This work was done in December 1981 and looked promising. The second box rig, again using three 6-kVA lamps, was operated to obtain instrumentation durability information and initial data input to a Finite Element Model. This limited test program was conducted in August 1983. Five test plates were run. Instrumentation consisted of strain gages, thermocouples and thermal paint. The strain gages were found to fail at 1200 F as expected though plates were heated to 1700 F. The third box rig, containing four 6-kVA lamps, is in build up for testing to begin in late October 1983. In addition to 33 percent greater power input, this rig has provision for 400 F backside line cooling air and a viewing port suitable for IR camera viewing. The casing is also water cooled for extended durability.

  15. Connections between Star Cluster Populations and Their Host Galaxy Nuclear Rings

    Science.gov (United States)

    Ma, Chao; de Grijs, Richard; Ho, Luis C.

    2018-04-01

    Nuclear rings are excellent laboratories for probing diverse phenomena such as the formation and evolution of young massive star clusters and nuclear starbursts, as well as the secular evolution and dynamics of their host galaxies. We have compiled a sample of 17 galaxies with nuclear rings, which are well resolved by high-resolution Hubble and Spitzer Space Telescope imaging. For each nuclear ring, we identified the ring star cluster population, along with their physical properties (ages, masses, and extinction values). We also determined the integrated ring properties, including the average age, total stellar mass, and current star formation rate (SFR). We find that Sb-type galaxies tend to have the highest ring stellar mass fraction with respect to the host galaxy, and this parameter is correlated with the ring’s SFR surface density. The ring SFRs are correlated with their stellar masses, which is reminiscent of the main sequence of star-forming galaxies. There are striking correlations between star-forming properties (i.e., SFR and SFR surface density) and nonaxisymmetric bar parameters, appearing to confirm previous inferences that strongly barred galaxies tend to have lower ring SFRs, although the ring star formation histories turn out to be significantly more complicated. Nuclear rings with higher stellar masses tend to be associated with lower cluster mass fractions, but there is no such relation for the ages of the rings. The two youngest nuclear rings in our sample, NGC 1512 and NGC 4314, which have the most extreme physical properties, represent the young extremity of the nuclear ring age distribution.

  16. Chronic caffeine consumption prevents cognitive decline from young to middle age in rats, and is associated with increased length, branching, and spine density of basal dendrites in CA1 hippocampal neurons.

    Science.gov (United States)

    Vila-Luna, S; Cabrera-Isidoro, S; Vila-Luna, L; Juárez-Díaz, I; Bata-García, J L; Alvarez-Cervera, F J; Zapata-Vázquez, R E; Arankowsky-Sandoval, G; Heredia-López, F; Flores, G; Góngora-Alfaro, J L

    2012-01-27

    Chronic caffeine consumption has been inversely associated with the risk of developing dementia and Alzheimer's disease. Here we assessed whether chronic caffeine treatment prevents the behavioral and cognitive decline that male Wistar rats experience from young (≈3 months) to middle age (≈10 months). When animals were young they were evaluated at weekly intervals in three tests: motor activity habituation in the open field (30-min sessions at the same time on consecutive days), continuous spontaneous alternation in the Y-maze (8 min), and elevated plus-maze (5 min). Afterward, rats from the same litter were randomly assigned either to a caffeine-treated group (n=13) or a control group (n=11), which received only tap water. Caffeine treatment (5 mg/kg/day) began when animals were ≈4 months old, and lasted for 6 months. Behavioral tests were repeated from day 14 to day 28 after caffeine withdrawal, a time period that is far in excess for the full excretion of a caffeine dose in this species. Thirty days after caffeine discontinuation brains were processed for Golgi-Cox staining. Compared with controls, we found that middle-aged rats that had chronically consumed low doses of caffeine (1) maintained their locomotor habituation during the second consecutive day exposure to the open field (an index of non-associative learning), (2) maintained their exploratory drive to complete the conventional minimum of nine arm visits required to calculate the alternation performance in the Y-maze in a greater proportion, (3) maintained their alternation percentage above chance level (an index of working memory), and (4) did not increase the anxiety indexes assessed by measuring the time spent in the open arms of the elevated plus maze. In addition, morphometric analysis of hippocampal neurons revealed that dendritic branching (90-140 μm from the soma), length of 4th and 5th order branches, total dendritic length, and spine density in distal dendritic branches were greater in

  17. Host range, host ecology, and distribution of more than 11800 fish parasite species

    Science.gov (United States)

    Strona, Giovanni; Palomares, Maria Lourdes D.; Bailly, Nicholas; Galli, Paolo; Lafferty, Kevin D.

    2013-01-01

    Our data set includes 38 008 fish parasite records (for Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda) compiled from the scientific literature, Internet databases, and museum collections paired to the corresponding host ecological, biogeographical, and phylogenetic traits (maximum length, growth rate, life span, age at maturity, trophic level, habitat preference, geographical range size, taxonomy). The data focus on host features, because specific parasite traits are not consistently available across records. For this reason, the data set is intended as a flexible resource able to extend the principles of ecological niche modeling to the host–parasite system, providing researchers with the data to model parasite niches based on their distribution in host species and the associated host features. In this sense, the database offers a framework for testing general ecological, biogeographical, and phylogenetic hypotheses based on the identification of hosts as parasite habitat. Potential applications of the data set are, for example, the investigation of species–area relationships or the taxonomic distribution of host-specificity. The provided host–parasite list is that currently used by Fish Parasite Ecology Software Tool (FishPEST, http://purl.oclc.org/fishpest), which is a website that allows researchers to model several aspects of the relationships between fish parasites and their hosts. The database is intended for researchers who wish to have more freedom to analyze the database than currently possible with FishPEST. However, for readers who have not seen FishPEST, we recommend using this as a starting point for interacting with the database.

  18. Host factors in nidovirus replication

    NARCIS (Netherlands)

    Wilde, Adriaan Hugo de

    2013-01-01

    The interplay between nidoviruses and the infected host cell was investigated. Arterivirus RNA-synthesising activity was shown to depend on intact membranes and on a cytosolic host protein which does not cosediment with the RTC. Furthermore, the immunosuppressant drug cyclosporin A (CsA) blocks

  19. Host Adaptation of Staphylococcal Leukocidins

    NARCIS (Netherlands)

    Vrieling, M

    2016-01-01

    Staphylococcus aureus is a human and animal pathogen of global importance and has the capacity to cause disease in distinct host populations, using a large arsenal of secreted proteins to evade the host immune response. Amongst the immune evasion proteins of S. aureus, secreted cytotoxins play a

  20. Association between Dietary Carotenoid Intake and Bone Mineral Density in Korean Adults Aged 30–75 Years Using Data from the Fourth and Fifth Korean National Health and Nutrition Examination Surveys (2008–2011

    Directory of Open Access Journals (Sweden)

    Gebereamanuel Meron Regu

    2017-09-01

    Full Text Available Age-related bone loss is a major public health problem. This cross-sectional study examined the association between the dietary intake of carotenoids and bone mineral density (BMD. Data from 8022 subjects (3763 males and 4259 females aged 30–75 years included in the Korean National Health and Nutrition Examination Survey (2008–2011 were analyzed. BMD was measured by dual-energy X-ray absorptiometry. Intake of carotenoids was estimated using 24-h dietary recall. In multiple linear analysis, after adjusting for covariates, lutein + zeaxanthin and β-cryptoxanthin intake was positively associated with total hip BMD in males and premenopausal women respectively, while β-carotene intake was positively correlated with femoral neck, total hip, and whole-body BMD in postmenopausal women. Postmenopausal women in the highest quintile of daily β-carotene intake, showed a lower risk of osteopenia at the lumbar spine (odds ratio (OR: 0.35, 95% CI: 0.16–0.79, P for trend = 0.009 than those in the lowest quintile, after adjusting for covariates. Daily β-cryptoxanthin intake was significantly associated with a lower risk of osteopenia at the total hip (OR per 1 mg/day increase: 0.76; 95% CI: 0.59–0.97, and lumbar spine (OR per 1 mg/day increase: 0.79; 95% CI: 0.70–0.89 in postmenopausal women. These results suggest that the dietary intake of β-carotene and β-cryptoxanthin may have a positive effect on bone health.

  1. Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest

    Science.gov (United States)

    The Janzen-Connell (JC) hypothesis provides a powerful framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet -- that recruits experience high mortality near conspecifics and at high densities -- assumes a degree of host specialization in interactions betwe...

  2. Ebola virus host cell entry.

    Science.gov (United States)

    Sakurai, Yasuteru

    2015-01-01

    Ebola virus is an enveloped virus with filamentous structure and causes a severe hemorrhagic fever in human and nonhuman primates. Host cell entry is the first essential step in the viral life cycle, which has been extensively studied as one of the therapeutic targets. A virus factor of cell entry is a surface glycoprotein (GP), which is an only essential viral protein in the step, as well as the unique particle structure. The virus also interacts with a lot of host factors to successfully enter host cells. Ebola virus at first binds to cell surface proteins and internalizes into cells, followed by trafficking through endosomal vesicles to intracellular acidic compartments. There, host proteases process GPs, which can interact with an intracellular receptor. Then, under an appropriate circumstance, viral and endosomal membranes are fused, which is enhanced by major structural changes of GPs, to complete host cell entry. Recently the basic research of Ebola virus infection mechanism has markedly progressed, largely contributed by identification of host factors and detailed structural analyses of GPs. This article highlights the mechanism of Ebola virus host cell entry, including recent findings.

  3. Testing local host adaptation and phenotypic plasticity in a herbivore when alternative related host plants occur sympatrically.

    Directory of Open Access Journals (Sweden)

    Lorena Ruiz-Montoya

    Full Text Available Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, were assessed in order to measure the extent of phenotypic plasticity in morphological and life history traits in relation to the host plants. We obtained an index of phenotypic plasticity for each genotype. Morphological variation of aphids was summarized by principal components analysis. Significant effects of recipient host on morphological variation and life history traits (establishment, age at first reproduction, number of nymphs, and intrinsic growth rate were detected. We did not detected genotype × host plant interaction; in general the genotypes developed better on B. campestris, independent of the host plant species from which they were collected. Therefore, there was no evidence to suggest local adaptation. Regarding plasticity, significant differences among genotypes in the index of plasticity were detected. Furthermore, significant selection on PC1 (general aphid body size on B. campestris, and on PC1 and PC2 (body length relative to body size on B. oleracea was detected. The elevation of the reaction norm of PC1 and the slope of the reaction norm for PC2 (i.e., plasticity were under directional selection. Thus, host plant species constitute distinct selective environments for B. brassicae. Aphid genotypes expressed different phenotypes in response to the host plant with low or nil fitness costs. Phenotypic plasticity and gene flow limits natural selection for host specialization promoting the maintenance of genetic variation in host exploitation.

  4. Characteristics of airborne plutonium resuspended from near-background aged surface-sources

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1982-11-01

    Plutonium content in samples of airborne solids collected at five Hanford sites was determined in several experiments directed toward investigating resuspension processes for aged surface sources. Though airborne plutonium concentrations are extremely low, radiochemical technique sensitivities allow plutonium characterization to be considered as a function of host-particle diameter in samples of airborne solids. Plutonium concentrations and activity densities are a function of aerodynamic particle diameter, sampling height, wind speed, wind direction and plutonium isotopic ratios

  5. Mammography density estimation with automated volumetic breast density measurement

    International Nuclear Information System (INIS)

    Ko, Su Yeon; Kim, Eun Kyung; Kim, Min Jung; Moon, Hee Jung

    2014-01-01

    To compare automated volumetric breast density measurement (VBDM) with radiologists' evaluations based on the Breast Imaging Reporting and Data System (BI-RADS), and to identify the factors associated with technical failure of VBDM. In this study, 1129 women aged 19-82 years who underwent mammography from December 2011 to January 2012 were included. Breast density evaluations by radiologists based on BI-RADS and by VBDM (Volpara Version 1.5.1) were compared. The agreement in interpreting breast density between radiologists and VBDM was determined based on four density grades (D1, D2, D3, and D4) and a binary classification of fatty (D1-2) vs. dense (D3-4) breast using kappa statistics. The association between technical failure of VBDM and patient age, total breast volume, fibroglandular tissue volume, history of partial mastectomy, the frequency of mass > 3 cm, and breast density was analyzed. The agreement between breast density evaluations by radiologists and VBDM was fair (k value = 0.26) when the four density grades (D1/D2/D3/D4) were used and moderate (k value = 0.47) for the binary classification (D1-2/D3-4). Twenty-seven women (2.4%) showed failure of VBDM. Small total breast volume, history of partial mastectomy, and high breast density were significantly associated with technical failure of VBDM (p 0.001 to 0.015). There is fair or moderate agreement in breast density evaluation between radiologists and VBDM. Technical failure of VBDM may be related to small total breast volume, a history of partial mastectomy, and high breast density.

  6. Effects of host-plant population size and plant sex on a specialist leaf-miner

    DEFF Research Database (Denmark)

    Bañuelos, María-José; Kollmann, Johannes Christian

    2011-01-01

    of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different...... punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively...... stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size...

  7. High virulence of Wolbachia after host switching: when autophagy hurts.

    Directory of Open Access Journals (Sweden)

    Winka Le Clec'h

    Full Text Available Wolbachia are widespread endosymbionts found in a large variety of arthropods. While these bacteria are generally transmitted vertically and exhibit weak virulence in their native hosts, a growing number of studies suggests that horizontal transfers of Wolbachia to new host species also occur frequently in nature. In transfer situations, virulence variations can be predicted since hosts and symbionts are not adapted to each other. Here, we describe a situation where a Wolbachia strain (wVulC becomes a pathogen when transfected from its native terrestrial isopod host species (Armadillidium vulgare to another species (Porcellio d. dilatatus. Such transfer of wVulC kills all recipient animals within 75 days. Before death, animals suffer symptoms such as growth slowdown and nervous system disorders. Neither those symptoms nor mortalities were observed after injection of wVulC into its native host A. vulgare. Analyses of wVulC's densities in main organs including Central Nervous System (CNS of both naturally infected A. vulgare and transfected P. d. dilatatus and A. vulgare individuals revealed a similar pattern of host colonization suggesting an overall similar resistance of both host species towards this bacterium. However, for only P. d. dilatatus, we observed drastic accumulations of autophagic vesicles and vacuoles in the nerve cells and adipocytes of the CNS from individuals infected by wVulC. The symptoms and mortalities could therefore be explained by this huge autophagic response against wVulC in P. d. dilatatus cells that is not triggered in A. vulgare. Our results show that Wolbachia (wVulC can lead to a pathogenic interaction when transferred horizontally into species that are phylogenetically close to their native hosts. This change in virulence likely results from the autophagic response of the host, strongly altering its tolerance to the symbiont and turning it into a deadly pathogen.

  8. Urban heat island effect on cicada densities in metropolitan Seoul

    Directory of Open Access Journals (Sweden)

    Hoa Q. Nguyen

    2018-01-01

    Full Text Available Background Urban heat island (UHI effect, the ubiquitous consequence of urbanization, is considered to play a major role in population expansion of numerous insects. Cryptotympana atrata and Hyalessa fuscata are the most abundant cicada species in the Korean Peninsula, where their population densities are higher in urban than in rural areas. We predicted a positive relationship between the UHI intensities and population densities of these two cicada species in metropolitan Seoul. Methods To test this prediction, enumeration surveys of cicada exuviae densities were conducted in 36 localities located within and in the vicinity of metropolitan Seoul. Samples were collected in two consecutive periods from July to August 2015. The abundance of each species was estimated by two resource-weighted densities, one based on the total geographic area, and the other on the total number of trees. Multiple linear regression analyses were performed to identify factors critical for the prevalence of cicada species in the urban habitat. Results C. atrata and H. fuscata were major constituents of cicada species composition collected across all localities. Minimum temperature and sampling period were significant factors contributing to the variation in densities of both species, whereas other environmental factors related to urbanization were not significant. More cicada exuviae were collected in the second rather than in the first samplings, which matched the phenological pattern of cicadas in metropolitan Seoul. Cicada population densities increased measurably with the increase in temperature. Age of residential complex also exhibited a significantly positive correlation to H. fuscata densities, but not to C. atrata densities. Discussion Effects of temperature on cicada densities have been discerned from other environmental factors, as cicada densities increased measurably in tandem with elevated temperature. Several mechanisms may contribute to the abundance of

  9. Digbeth hosts the Big Bang

    CERN Multimedia

    2002-01-01

    Birminham museum of science and discovery, Thinktank, is hosting 'Building The Universe', a free exhibition about the work undertaken at the European Laboratory for Particle Physics, in Geneva (3 paragraphs).

  10. Effect of calcium and vitamin D supplementation on bone mineral density in women aged 65-71 years: a 3-year randomized population-based trial (OSTPRE-FPS).

    Science.gov (United States)

    Kärkkäinen, M; Tuppurainen, M; Salovaara, K; Sandini, L; Rikkonen, T; Sirola, J; Honkanen, R; Jurvelin, J; Alhava, E; Kröger, H

    2010-12-01

    The Osteoporosis Risk Factor and Prevention-Fracture Prevention Study (OSTPRE-FPS) was a randomized population-based open trial (n = 593). The supplementation group (n = 287) received daily cholecalciferol 800 IU + calcium 1,000 mg for 3 years while the control group (n = 306) received neither supplementation nor placebo. Daily vitamin D and calcium supplementation have a positive effect on the skeleton in ambulatory postmenopausal women. vitamin D deficiency is common in the elderly, and vitamin D levels are associated with low bone mineral density (BMD). The working hypothesis was that vitamin D and calcium supplementation could prevent bone loss in ambulatory postmenopausal women. the OSTPRE-FPS was a randomized population-based open trial with a 3-year follow-up in 3,432 women (aged 66 to 71 years). A randomly selected subsample of 593 subjects underwent BMD measurements. The supplementation group (n = 287) received daily cholecalciferol 800 IU + calcium 1,000 mg for 3 years while the control group (n = 306) received neither supplementation nor placebo. in the intention-to-treat analysis, total body BMD (n = 362) increased significantly more in the intervention group than in the control group (0.84% vs. 0.19%, p = 0.011). The BMD change differences at the lumbar spine (p = 0.372), femoral neck (p = 0.188), trochanter (p = 0.085), and total proximal femur (p = 0.070) were statistically nonsignificant. Analyses in compliant women (≥ 80% of use) resulted in stronger and statistically significant effects at the total body and femoral regions. daily vitamin D and calcium supplementation have a positive effect on the skeleton in ambulatory postmenopausal women with adequate nutritional calcium intake.

  11. Symbiotic Origin of Aging.

    Science.gov (United States)

    Greenberg, Edward F; Vatolin, Sergei

    2018-06-01

    Normally aging cells are characterized by an unbalanced mitochondrial dynamic skewed toward punctate mitochondria. Genetic and pharmacological manipulation of mitochondrial fission/fusion cycles can contribute to both accelerated and decelerated cellular or organismal aging. In this work, we connect these experimental data with the symbiotic theory of mitochondrial origin to generate new insight into the evolutionary origin of aging. Mitochondria originated from autotrophic α-proteobacteria during an ancient endosymbiotic event early in eukaryote evolution. To expand beyond individual host cells, dividing α-proteobacteria initiated host cell lysis; apoptosis is a product of this original symbiont cell lytic exit program. Over the course of evolution, the host eukaryotic cell attenuated the harmful effect of symbiotic proto-mitochondria, and modern mitochondria are now functionally interdependent with eukaryotic cells; they retain their own circular genomes and independent replication timing. In nondividing differentiated or multipotent eukaryotic cells, intracellular mitochondria undergo repeated fission/fusion cycles, favoring fission as organisms age. The discordance between cellular quiescence and mitochondrial proliferation generates intracellular stress, eventually leading to a gradual decline in host cell performance and age-related pathology. Hence, aging evolved from a conflict between maintenance of a quiescent, nonproliferative state and the evolutionarily conserved propagation program driving the life cycle of former symbiotic organisms: mitochondria.

  12. Aging, longevity and health

    DEFF Research Database (Denmark)

    Rasmussen, Lene Juel; Sander, Miriam; Wewer, Ulla M.

    2011-01-01

    The IARU Congress on Aging, Longevity and Health, held on 5-7 October 2010 in Copenhagen, Denmark, was hosted by Rector Ralf Hemmingsen, University of Copenhagen and Dean Ulla Wewer, Faculty of Health Sciences, University of Copenhagen and was organized by Center for Healthy Aging (CEHA) under......, Muscle and Life Span and Life Span and Mechanisms. Two additional Sessions highlighted ongoing research in the recently established Center for Healthy Aging at the University of Copenhagen. This report highlights outcomes of recent research on aging-related topics, as described at the IARU Congress...... on Aging, Longevity and Health....

  13. The distribution of weaver ant pheromones on host trees

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2007-01-01

    The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested for ...... to leaves. Also there was a positive correlation between spot density and the likelihood of being detected by ants. Anal spots may thus function as reliable cues to interacting species and be an important factor in shaping the community around Oecophylla colonies.......The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested...... for correlations between spot density, ant activity and the likelihood of being detected by an ant. Spots were only found on trees with ants. On ant-trees, spots were distributed throughout the trees but with higher densities in areas with high ant activity and pheromone densities were higher on twigs compared...

  14. Spectro-photometric study of the GRB 030329 host galaxy

    International Nuclear Information System (INIS)

    Gorosabel, J.; Ramirez, D. Perez

    2005-01-01

    In this study we present optical/near-infrared (NIR) broad band photometry and optical spectroscopic observations of the GRB 030329 host galaxy. The Spectral Energy Distribution (SED) of the host is consistent with a starburst galaxy template with a dominant stellar population age of ∼ 150 Myr and an extinction A ν ∼ 0.6. Analysis of the spectral emission lines shows that the host is likely a low metallicity galaxy. Two independent diagnostics, based on the restframe UV continuum and the [OII] line flux, provide a consistent unextincted star formation rate of SFRN ∼ 0.6 Myr -1 . The low absolute magnitude of the host (M B ∼ -16.5) implies a high specific star formation rate value, SSFR ≅ 34 Myr -1 (L/L) -1

  15. Selection of the host rock for high level radioactive waste repository in China

    International Nuclear Information System (INIS)

    Jin Yuanxin; Wang Wenguang; Chen Zhangru

    2001-01-01

    The authors has briefly introduced the experiences of the host rock selection and the host rock types in other countries for high level radioactive waste repository. The potential host rocks in China are investigated. They include granite, tuff, clay, basalt, salt, and loess. The report has expounded the distributions, scale, thickness, mineral and chemical composition, construction, petrogenesis and the ages of the rock. The possibility of these rocks as the host rock has been studied. The six pieces of distribution map of potential rocks have been made up. Through the synthetical study, it is considered that granite as the host rock of high level radioactive waste repository is possible

  16. Two different strategies of host manipulation allow parasites to persist in intermediate-definitive host systems

    NARCIS (Netherlands)

    Vries, de L.J.; Langevelde, van F.

    2018-01-01

    Trophically transmitted parasites start their development in an intermediate host, before they finish the development in their definitive host when the definitive host preys on the intermediate host. In intermediate-definitive host systems, two strategies of host manipulation have been evolved:

  17. Asteroseismology of the Transiting Exoplanet Host HD 17156 with Hubble Space Telescope Fine Guidance Sensor

    DEFF Research Database (Denmark)

    Gilliland, Ronald L.; McCullough, Peter R.; Nelan, Edmund P.

    2011-01-01

    light curve. Using the density constraint from asteroseismology, and stellar evolution modeling results in M * = 1.285 ± 0.026 M sun, R * = 1.507 ± 0.012 R sun, and a stellar age of 3.2 ± 0.3 Gyr. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science......Observations conducted with the Fine Guidance Sensor on the Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in 2008 December on the host star of the transiting exoplanet HD 17156b. During this time, 1.0 × 1012 photons...... Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555....

  18. Transmission or Within-Host Dynamics Driving Pulses of Zoonotic Viruses in Reservoir-Host Populations.

    Directory of Open Access Journals (Sweden)

    Raina K Plowright

    2016-08-01

    Full Text Available Progress in combatting zoonoses that emerge from wildlife is often constrained by limited knowledge of the biology of pathogens within reservoir hosts. We focus on the host-pathogen dynamics of four emerging viruses associated with bats: Hendra, Nipah, Ebola, and Marburg viruses. Spillover of bat infections to humans and domestic animals often coincides with pulses of viral excretion within bat populations, but the mechanisms driving such pulses are unclear. Three hypotheses dominate current research on these emerging bat infections. First, pulses of viral excretion could reflect seasonal epidemic cycles driven by natural variations in population densities and contact rates among hosts. If lifelong immunity follows recovery, viruses may disappear locally but persist globally through migration; in either case, new outbreaks occur once births replenish the susceptible pool. Second, epidemic cycles could be the result of waning immunity within bats, allowing local circulation of viruses through oscillating herd immunity. Third, pulses could be generated by episodic shedding from persistently infected bats through a combination of physiological and ecological factors. The three scenarios can yield similar patterns in epidemiological surveys, but strategies to predict or manage spillover risk resulting from each scenario will be different. We outline an agenda for research on viruses emerging from bats that would allow for differentiation among the scenarios and inform development of evidence-based interventions to limit threats to human and animal health. These concepts and methods are applicable to a wide range of pathogens that affect humans, domestic animals, and wildlife.

  19. Parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) Adjusts Reproductive Strategy When Competing for Hosts.

    Science.gov (United States)

    Kant, Rashmi; Minor, Maria A

    2017-06-01

    Parasitoid fitness depends on its ability to manipulate reproductive strategies when in competition. This study investigated the parasitism and sex allocation strategies of the parasitic wasp Diaeretiella rapae McIntosh at a range of host (Brevicoryne brassicae L.) and conspecific densities. The results suggest that D. rapae females adjust their progeny production and progeny sex ratio with changing competition. When foraging alone, female D. rapae parasitize larger number of B. brassicae nymphs when the number of available hosts is increased, but the overall proportion of parasitized hosts decreases with increase in host density. The proportion of female offspring also decreases with elevated host density. Increase in the number of female D. rapae foraging together increased total parasitism, but reduced relative contribution of each individual female. The number of female progeny decreased when multiple females competed for the same host. However, foraging experience in the presence of one or more conspecifics increased the parasitism rate and proportion of female progeny. Competing females were more active during oviposition and had shorter lives. The study suggests that both host and foundress (female parasitoid) densities have significant effect on progeny production, sex allocation, and longevity of foraging females. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. The Inflammasome in Host Defense

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2009-12-01

    Full Text Available Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes.

  1. Host factors influencing viral persistence

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Nansen, A; Ørding Andreasen, Susanne

    2000-01-01

    host were used. Our results reveal that very different outcomes may be observed depending on virus strain and immunocompetence of the host. Thus while CD4+ cells are not critical during the initial phase of virus control, infectious virus reappear in mice lacking CD4+ cells, B cells or CD40 ligand...... replication, mice lacking the ability to produce interferon-gamma may develop either a severe, mostly fatal, T-cell mediated wasting syndrome or a chronic infection characterized by long-term coexistence of antiviral cytotoxic T lymphocytes and infectious virus. Mathematical modelling indicates...

  2. Intraspecific competition: the role of lags between attack and death in host-parasitoid interactions.

    Science.gov (United States)

    Cameron, T C; Metcalfe, D; Beckerman, A P; Sait, S M

    2007-05-01

    Many natural enemies do not immediately kill their host, and the lag this creates between attack and host death results in mixed populations of uninfected and infected hosts. Both competition and parasitism are known to be major structuring forces in ecological communities; however, surprisingly little is known about how the competitive nature of infected hosts could affect the survival and dynamics of remaining uninfected host populations. Using a laboratory system comprising the Indian meal moth, Plodia interpunctella, and a solitary koinobiont parasitoid, Venturia canescens, we address this question by conducting replicated competition experiments between the unparasitized and parasitized classes of host larvae. For varying proportions of parasitized host larvae and competitor densities, we consider the effects of competition within (intraclass) and between (interclass) unparasitized and parasitized larvae on the survival, development time, and size of adult moths and parasitoid wasps. The greatest effects were on survival: increased competitor densities reduced survival of both parasitized and unparasitized larvae. However, unparasitized larvae survival, but not parasitized larvae survival, was reduced by increasing interclass competition. To our knowledge, this is the first experimental demonstration of the competitive superiority of parasitized over unparasitized hosts for limiting resources. We discuss possible mechanisms for this phenomenon, why it may have evolved, and its possible influence on the stability of host-parasite dynamics.

  3. Host Defence to Pulmonary Mycosis

    Directory of Open Access Journals (Sweden)

    Christopher H Mody

    1999-01-01

    Full Text Available OBJECTIVE: To provide a basic understanding of the mechanisms of host defense to pathogenic fungi. This will help physicians understand why some patients are predisposed to fungal infections and update basic scientists on how microbial immunology applies to fungal disease.

  4. Intercultural Competence in Host Students?

    DEFF Research Database (Denmark)

    Egekvist, Ulla Egidiussen; Lyngdorf, Niels Erik; Du, Xiangyun

    2016-01-01

    Although substantial work in intercultural education has been done on the intercultural competences of mobile students engaging in international study visits, there is a need to explore intercultural competences in host students. This chapter seeks to answer questions about the challenges...

  5. Host Event Based Network Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  6. Feeder density enhances house finch disease transmission in experimental epidemics.

    Science.gov (United States)

    Moyers, Sahnzi C; Adelman, James S; Farine, Damien R; Thomason, Courtney A; Hawley, Dana M

    2018-05-05

    Anthropogenic food provisioning of wildlife can alter the frequency of contacts among hosts and between hosts and environmental sources of pathogens. Despite the popularity of garden bird feeding, few studies have addressed how feeders influence host contact rates and disease dynamics. We experimentally manipulated feeder density in replicate aviaries containing captive, pathogen-naive, groups of house finches ( Haemorhous mexicanus ) and continuously tracked behaviours at feeders using radio-frequency identification devices. We then inoculated one bird per group with Mycoplasma gallisepticum (Mg), a common bacterial pathogen for which feeders are fomites of transmission, and assessed effects of feeder density on house finch behaviour and pathogen transmission. We found that pathogen transmission was significantly higher in groups with the highest density of bird feeders, despite a significantly lower rate of intraspecific aggressive interactions relative to the low feeder density groups. Conversely, among naive group members that never showed signs of disease, we saw significantly higher concentrations of Mg-specific antibodies in low feeder density groups, suggesting that birds in low feeder density treatments had exposure to subclinical doses of Mg. We discuss ways in which the density of garden bird feeders could play an important role in mediating the intensity of Mg epidemics.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'. © 2018 The Author(s).

  7. Stellar Companions of Exoplanet Host Stars in K2

    Science.gov (United States)

    Matson, Rachel; Howell, Steve; Horch, Elliott; Everett, Mark

    2018-01-01

    Stellar multiplicity has significant implications for the detection and characterization of exoplanets. A stellar companion can mimic the signal of a transiting planet or distort the true planetary radii, leading to improper density estimates and over-predicting the occurrence rates of Earth-sized planets. Determining the fraction of exoplanet host stars that are also binaries allows us to better determine planetary characteristics as well as establish the relationship between binarity and planet formation. Using high-resolution speckle imaging to obtain diffraction limited images of K2 planet candidate host stars we detect stellar companions within one arcsec and up to six magnitudes fainter than the host star. By comparing our observed companion fraction to TRILEGAL star count simulations, and using the known detection limits of speckle imaging, we find the binary fraction of K2 planet host stars to be similar to that of Kepler host stars and solar-type field stars. Accounting for stellar companions in exoplanet studies is therefore essential for deriving true stellar and planetary properties as well as maximizing the returns for TESS and future exoplanet missions.

  8. Host jumps shaped the diversity of extant rust fungi (Pucciniales).

    Science.gov (United States)

    McTaggart, Alistair R; Shivas, Roger G; van der Nest, Magriet A; Roux, Jolanda; Wingfield, Brenda D; Wingfield, Michael J

    2016-02-01

    The aim of this study was to determine the evolutionary time line for rust fungi and date key speciation events using a molecular clock. Evidence is provided that supports a contemporary view for a recent origin of rust fungi, with a common ancestor on a flowering plant. Divergence times for > 20 genera of rust fungi were studied with Bayesian evolutionary analyses. A relaxed molecular clock was applied to ribosomal and mitochondrial genes, calibrated against estimated divergence times for the hosts of rust fungi, such as Acacia (Fabaceae), angiosperms and the cupressophytes. Results showed that rust fungi shared a most recent common ancestor with a mean age between 113 and 115 million yr. This dates rust fungi to the Cretaceous period, which is much younger than previous estimations. Host jumps, whether taxonomically large or between host genera in the same family, most probably shaped the diversity of rust genera. Likewise, species diversified by host shifts (through coevolution) or via subsequent host jumps. This is in contrast to strict coevolution with their hosts. Puccinia psidii was recovered in Sphaerophragmiaceae, a family distinct from Raveneliaceae, which were regarded as confamilial in previous studies. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  9. The Evolution of the Stellar Hosts of Radio Galaxies

    International Nuclear Information System (INIS)

    Lacy, Mark; Bunker, Andrew J.; Ridgway, Susan E.

    2000-01-01

    We present new near-infrared images of z>0.8 radio galaxies from the flux-limited 7C-iii sample of radio sources for which we have recently obtained almost complete spectroscopic redshifts. The 7C objects have radio luminosities ≅20 times fainter than 3C radio galaxies at a given redshift. The absolute magnitudes of the underlying host galaxies and their scale sizes are only weakly dependent on radio luminosity. Radio galaxy hosts at z∼2 are significantly brighter than the hosts of radio-quiet quasars at similar redshifts and the recent model AGN hosts of Kauffmann and Haehnelt. There is no evidence for strong evolution in scale size, which shows a large scatter at all redshifts. The hosts brighten significantly with redshift, consistent with the passive evolution of a stellar population that formed at z(greater-or-similar sign)3. This scenario is consistent with studies of host galaxy morphology and submillimeter continuum emission, both of which show strong evolution at z(greater-or-similar sign)2.5. The lack of a strong ''redshift cutoff'' in the radio luminosity function to z>4 suggests that the formation epoch of the radio galaxy host population lasts (greater-or-similar sign)1 Gyr, from z(greater-or-similar sign)5 to z∼3. We suggest these facts are best explained by models in which the most massive galaxies and their associated AGN form early because of high baryon densities in the centers of their dark matter haloes. (c) 2000 The American Astronomical Society

  10. Leaf morphophysiology of a Neotropical mistletoe is shaped by seasonal patterns of host leaf phenology.

    Science.gov (United States)

    Scalon, Marina Corrêa; Rossatto, Davi Rodrigo; Domingos, Fabricius Maia Chaves Bicalho; Franco, Augusto Cesar

    2016-04-01

    Several mistletoe species are able to grow and reproduce on both deciduous and evergreen hosts, suggesting a degree of plasticity in their ability to cope with differences in intrinsic host functions. The aim of this study was to investigate the influence of host phenology on mistletoe water relations and leaf gas exchange. Mistletoe Passovia ovata parasitizing evergreen (Miconia albicans) hosts and P. ovata parasitizing deciduous (Byrsonima verbascifolia) hosts were sampled in a Neotropical savanna. Photosynthetic parameters, diurnal cycles of stomatal conductance, pre-dawn and midday leaf water potential, and stomatal anatomical traits were measured during the peak of the dry and wet seasons, respectively. P. ovata showed distinct water-use strategies that were dependent on host phenology. For P. ovata parasitizing the deciduous host, water use efficiency (WUE; ratio of photosynthetic rate to transpirational water loss) was 2-fold lower in the dry season than in the wet season; in contrast, WUE was maintained at the same level during the wet and dry seasons in P. ovata parasitizing the evergreen host. Generally, mistletoe and host diurnal cycles of stomatal conductance were linked, although there were clear differences in leaf water potential, with mistletoe showing anisohydric behaviour and the host showing isohydric behaviour. Compared to mistletoes attached to evergreen hosts, those parasitizing deciduous hosts had a 1.4-fold lower stomatal density and 1.2-fold wider stomata on both leaf surfaces, suggesting that the latter suffered less intense drought stress. This is the first study to show morphophysiological differences in the same mistletoe species parasitizing hosts of different phenological groups. Our results provide evidence that phenotypical plasticity (anatomical and physiological) might be essential to favour the use of a greater range of hosts.

  11. Successful Aging

    Directory of Open Access Journals (Sweden)

    Taufiqurrahman Nasihun

    2015-06-01

    . There are gradual decline of physiological functions in human after becoming adult in life. The declining of physiological functions might be define as decrease in protein synthesis capacity, bone mineral density, immunological function, strength and muscle mass, and otherwise increase in fat accumulation (Rudman D, et al. 1982; Charmpilas N, et al. 2015. Epidemiologic study indicated that the predominant cause of morbidity, mortality, and reduced longevity in cohort were acute and chronic inflammatory as well as oxidative stress, resulted from environmental inflammations, infections, obesity, and social distress. Acute inflammatory is commonly caused by biological agent, especially both or either bacterial and or viral, whereas chronic inflammatory is related to environmental inflammagen, obesity, and social distress (Sone H et al. 2010 Chronic oxidative stress injures cells particularly in regulatory sytem such as endocrine, nervous, immune, and the neuro-endocrine immune communication by wich cell loss its homeostasis regulatory and cannot preserve health (De la Fuente. 2009. Subsequently, it will impaire homeostasis that leads to an increase in the morbidity and mortality of aging. Likely, answer to the question of where aging start is from the mitochondrial cells of regulatory system. Various evidences indicate that the rate of mitochondrial oxygen radical generation, the degree of membrane fatty acid unsaturation, and oxidative damage to mitochodrial DNA are lower in the long-live species compared to short live species (Braja G, 2004. Several studies also indicate that majority of human adults die due to complication of atherosclerosis, cancer, dimentia, whereas in healthy age  invariably accompanied by muscle weakness, and make them frail, disabled, and dependent before eventually died. Such disability prominently caused by skeletal muscle weakness due to diminution of muscle mass and its nerve, osteoarthrirtis, and others chronic degenerative diseases related

  12. Location of Host and Host Habitat by Fruit Fly Parasitoids

    Directory of Open Access Journals (Sweden)

    Pascal Rousse

    2012-11-01

    Full Text Available Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae. Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.

  13. Laboratory Density Functionals

    OpenAIRE

    Giraud, B. G.

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  14. High density data recording for SSCL linac

    International Nuclear Information System (INIS)

    VanDeusen, A.L.; Crist, C.

    1993-01-01

    The Superconducting Super Collider Laboratory and AlliedSignal Aerospace have collaboratively developed a high density data monitoring system for beam diagnostic activities. The 128 channel data system is based on a custom multi-channel high speed digitizer card for the VXI bus. The card is referred to as a Modular Input VXI (MIX) digitizer. Multiple MIX cards are used in the complete system to achieve the necessary high channel density requirements. Each MIX digitizer card also contains programmable signal conditioning, and enough local memory to complete an entire beam scan without assistance from the host processor

  15. Characterization of yields for Pinus taeda genotypes at the half-sib, full-sib, and varietal levels of genetic improvement at two planting densities at age 5 in the upper coastal plain of Georgia

    Science.gov (United States)

    Derek Dougherty; Michael Kane; Robert Teskey; Richard Daniels; Jeff Wright

    2012-01-01

    Seedling deployment options for the establishment of operational Pinus taeda plantations in the Southeastern U.S. now include half-sib families, full-sib crosses, and varietals. In 2005, a study to evaluate the effects of genotype and density on yield and quality was established on a moderately well-drained upland site in the Upper Coastal Plain in...

  16. Densidade mineral óssea, função pulmonar, idade cronológica e idade de diagnóstico em crianças e adolescentes com fibrose cística Bone mineral density, pulmonary function, chronological age, and age at diagnosis in children and adolescents with cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Márcio V.F. Donadio

    2013-04-01

    Full Text Available OBJETIVO: Avaliar a densidade mineral óssea de pacientes com fibrose cística (FC e correlacioná-la com possíveis variáveis intervenientes. MÉTODOS: Foram incluídos crianças e adolescentes com diagnóstico clínico de FC, idade entre seis e dezoito anos, e em acompanhamento ambulatorial. Primeiramente, foram coletados os dados demográficos, para posterior realização do teste espirométrico. Todos os pacientes responderam ao questionário de qualidade de vida em FC (QFC e realizaram o teste de caminhada dos seis minutos (TC6 e o exame de densitometria óssea (DXA. RESULTADOS: Foram incluídos 25 pacientes fibrocísticos, sendo 56% do sexo masculino. A média de idade foi de 12,3 ± 3,4 anos, altura de 149,2 ± 14,4 cm e peso de 44,4 ± 13,9 kg. A maioria dos dados de função pulmonar e de densidade mineral óssea (DMO encontrou-se dentro dos limites de normalidade. A média do volume expiratório forçado no primeiro segundo (VEF1 foi de 92,5 ± 23,6 (% do previsto, capacidade vital forçada (CVF de 104,4 ± 21,3 (% do previsto e o escore z da DMO de 0,1 ± 1,0. A DMO correlacionou-se de forma moderada com o VEF1 (r = 0,43; p = 0,03 e com a CVF (r = 0,57; p = 0,003. Em relação à idade cronológica e à idade de diagnóstico, também foi encontrada uma correlação moderada e inversa (r = -0,55; p = 0,004 /r = -0,57; p = 0,003, respectivamente. Entretanto, não foram encontradas correlações significativas com os dados do QFC, TC6 e índice de massa corporal. CONCLUSÃO: A maioria dos pacientes avaliados apresenta DMO dentro dos limites de normalidade e possui correlação positiva com a função pulmonar e negativa com a idade cronológica e a idade de diagnóstico.OBJECTIVE: To assess bone mineral density in patients with cystic fibrosis (CF, and to correlate it with possible intervening variables. METHODS: Children and adolescents diagnosed with CF, aged 6 to 18 years, followed at the outpatient clinic were included in the study

  17. HOST payload for STS-95 being moved into SSPF

    Science.gov (United States)

    1998-01-01

    The Hubble Space Telescope Orbiting Systems Test (HOST) is checked out by technicians in the Space Shuttle Processing Facility. One of the payloads on the STS-95 mission, the HOST platform is carrying four experiments to validate components planned for installation during the third Hubble Space Telescope servicing mission and to evaluate new technologies in an earth orbiting environment. The STS-95 mission is scheduled to launch Oct. 29. It will carry three other payloads: the Spartan solar- observing deployable spacecraft, the International Extreme Ultraviolet Hitchhiker, and the SPACEHAB single module with experiments on space flight and the aging process.

  18. Hosting the first EDRS payload

    Science.gov (United States)

    Poncet, D.; Glynn, S.; Heine, F.

    2017-11-01

    The European Data Relay System (EDRS) will provide optical and microwave data relay services between Low Earth Orbit (LEO) satellites at altitudes up to 2000 km and the ground through geostationary (GEO) satellite nodes. Currently, two such nodes have been procured as part of a Public Private Partnership (PPP) between Astrium (now Airbus Defence and Space) and ESA. The first node (EDRS-A) is a hosted payload embarked upon the Eutelsat 9B satellite and scheduled for launch in early 2015.

  19. Host thin films incorporating nanoparticles

    Science.gov (United States)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  20. Effects of host-plant population size and plant sex on a specialist leaf-miner

    Science.gov (United States)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  1. Inter-Population Variability of Endosymbiont Densities in the Asian Citrus Psyllid (Diaphorina citri Kuwayama).

    Science.gov (United States)

    Chu, Chia-Ching; Gill, Torrence A; Hoffmann, Mark; Pelz-Stelinski, Kirsten S

    2016-05-01

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is an insect pest capable of transmitting Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening in North America. D. citri also harbors three endosymbionts, Wolbachia, Candidatus Carsonella ruddii, and Candidatus Profftella armatura, which may influence D. citri physiology and fitness. Although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population variability in D. citri. The present work examined the densities of each endosymbiont in adult D. citri sampled from different populations using quantitative PCR. Under field conditions, the densities of all three endosymbionts positively correlated with each other, and they are associated with D. citri gender and locality. In addition, the infection density of CLas also varied across populations. Although an analysis pooling D. citri from different populations showed that CLas-infected individuals tended to have lower endosymbiont densities compared to uninfected individuals, the difference was not significant when the population was included as a factor in the analysis, suggesting that other population-specific factors may have stronger effects on endosymbiont densities. To determine whether there is a genetic basis to the density differences, endosymbiont densities between aged CLas-negative females of two D. citri populations reared under standardized laboratory conditions were compared. Results suggested that inter-population variability in Wolbachia infection density is associated with the genotypes of the endosymbiont or the host. Findings from this work could facilitate understanding of D. citri-bacterial associations that may benefit the development of approaches for managing citrus greening, such as prevention of CLas transmission.

  2. Densities of carbon foils

    International Nuclear Information System (INIS)

    Stoner, J.O. Jr.

    1991-01-01

    The densities of arc-evaporated carbon target foils have been measured by several methods. The density depends upon the method used to measure it; for the same surface density, values obtained by different measurement techniques may differ by fifty percent or more. The most reliable density measurements are by flotation, yielding a density of 2.01±0.03 g cm -3 , and interferometric step height with the surface density known from auxiliary measurements, yielding a density of 2.61±0.4 g cm -3 . The difference between these density values mayy be due in part to the compressive stresses that carbon films have while still on their substrates, uncertainties in the optical calibration of surface densities of carbon foils, and systematic errors in step-height measurements. Mechanical thickness measurements by micrometer caliper are unreliable due to nonplanarity of these foils. (orig.)

  3. Targeting hunter distribution based on host resource selection and kill sites to manage disease risk.

    Science.gov (United States)

    Dugal, Cherie J; van Beest, Floris M; Vander Wal, Eric; Brook, Ryan K

    2013-10-01

    Endemic and emerging diseases are rarely uniform in their spatial distribution or prevalence among cohorts of wildlife. Spatial models that quantify risk-driven differences in resource selection and hunter mortality of animals at fine spatial scales can assist disease management by identifying high-risk areas and individuals. We used resource selection functions (RSFs) and selection ratios (SRs) to quantify sex- and age-specific resource selection patterns of collared (n = 67) and hunter-killed (n = 796) nonmigratory elk (Cervus canadensis manitobensis) during the hunting season between 2002 and 2012, in southwestern Manitoba, Canada. Distance to protected area was the most important covariate influencing resource selection and hunter-kill sites of elk (AICw = 1.00). Collared adult males (which are most likely to be infected with bovine tuberculosis (Mycobacterium bovis) and chronic wasting disease) rarely selected for sites outside of parks during the hunting season in contrast to adult females and juvenile males. The RSFs showed selection by adult females and juvenile males to be negatively associated with landscape-level forest cover, high road density, and water cover, whereas hunter-kill sites of these cohorts were positively associated with landscape-level forest cover and increasing distance to streams and negatively associated with high road density. Local-level forest was positively associated with collared animal locations and hunter-kill sites; however, selection was stronger for collared juvenile males and hunter-killed adult females. In instances where disease infects a metapopulation and eradication is infeasible, a principle goal of management is to limit the spread of disease among infected animals. We map high-risk areas that are regularly used by potentially infectious hosts but currently underrepresented in the distribution of kill sites. We present a novel application of widely available data to target hunter distribution based on host resource

  4. Determinants of the Sympatric Host-Pathogen Relationship in Tuberculosis

    Science.gov (United States)

    David, Susana; Mateus, A. R. A.; Duarte, Elsa L.; Albuquerque, José; Portugal, Clara; Sancho, Luísa; Lavinha, João; Gonçalves, Guilherme

    2015-01-01

    Major contributions from pathogen genome analysis and host genetics have equated the possibility of Mycobacterium tuberculosis co-evolution with its human host leading to more stable sympatric host–pathogen relationships. However, the attribution to either sympatric or allopatric categories depends on the resolution or grain of genotypic characterization. We explored the influence on the sympatric host-pathogen relationship of clinical (HIV infection and multidrug-resistant tuberculosis [MDRTB]) and demographic (gender and age) factors in regards to the genotypic grain by using spacer oligonucleotide typing (spoligotyping) for classification of M. tuberculosis strains within the Euro-American lineage. We analyzed a total of 547 tuberculosis (TB) cases, from six year consecutive sampling in a setting with high TB-HIV coinfection (32.0%). Of these, 62.0% were caused by major circulating pathogen genotypes. The sympatric relationship was defined according to spoligotype in comparison to the international spoligotype database SpolDB4. While no significant association with Euro-American lineage was observed with any of the factors analyzed, increasing the resolution with spoligotyping evidenced a significant association of MDRTB with sympatric strains, regardless of the HIV status. Furthermore, distribution curves of the prevalence of sympatric and allopatric TB in relation to patients’ age showed an accentuation of the relevance of the age of onset in the allopatric relationship, as reflected in the trimodal distribution. On the contrary, sympatric TB was characterized by the tendency towards a typical (standard) distribution curve. Our results suggest that within the Euro-American lineage a greater degree of genotyping fine-tuning is necessary in modeling the biological processes behind the host-pathogen interplay. Furthermore, prevalence distribution of sympatric TB to age was suggestive of host genetic determinisms driven by more common variants. PMID:26529092

  5. Gamma-Ray Burst Host Galaxies Have "Normal" Luminosities.

    Science.gov (United States)

    Schaefer

    2000-04-10

    The galactic environment of gamma-ray bursts can provide good evidence about the nature of the progenitor system, with two old arguments implying that the burst host galaxies are significantly subluminous. New data and new analysis have now reversed this picture: (1) Even though the first two known host galaxies are indeed greatly subluminous, the next eight hosts have absolute magnitudes typical for a population of field galaxies. A detailed analysis of the 16 known hosts (10 with redshifts) shows them to be consistent with a Schechter luminosity function with R*=-21.8+/-1.0, as expected for normal galaxies. (2) Bright bursts from the Interplanetary Network are typically 18 times brighter than the faint bursts with redshifts; however, the bright bursts do not have galaxies inside their error boxes to limits deeper than expected based on the luminosities for the two samples being identical. A new solution to this dilemma is that a broad burst luminosity function along with a burst number density varying as the star formation rate will require the average luminosity of the bright sample (>6x1058 photons s-1 or>1.7x1052 ergs s-1) to be much greater than the average luminosity of the faint sample ( approximately 1058 photons s-1 or approximately 3x1051 ergs s-1). This places the bright bursts at distances for which host galaxies with a normal luminosity will not violate the observed limits. In conclusion, all current evidence points to gamma-ray burst host galaxies being normal in luminosity.

  6. Parasite fitness traits under environmental variation: disentangling the roles of a chytrid's immediate host and external environment.

    Science.gov (United States)

    Van den Wyngaert, Silke; Vanholsbeeck, Olivier; Spaak, Piet; Ibelings, Bas W

    2014-10-01

    Parasite environments are heterogeneous at different levels. The first level of variability is the host itself. The second level represents the external environment for the hosts, to which parasites may be exposed during part of their life cycle. Both levels are expected to affect parasite fitness traits. We disentangle the main and interaction effects of variation in the immediate host environment, here the diatom Asterionella formosa (variables host cell volume and host condition through herbicide pre-exposure) and variation in the external environment (variables host density and acute herbicide exposure) on three fitness traits (infection success, development time and reproductive output) of a chytrid parasite. Herbicide exposure only decreased infection success in a low host density environment. This result reinforces the hypothesis that chytrid zoospores use photosynthesis-dependent chemical cues to locate its host. At high host densities, chemotaxis becomes less relevant due to increasing chance contact rates between host and parasite, thereby following the mass-action principle in epidemiology. Theoretical support for this finding is provided by an agent-based simulation model. The immediate host environment (cell volume) substantially affected parasite reproductive output and also interacted with the external herbicide exposed environment. On the contrary, changes in the immediate host environment through herbicide pre-exposure did not increase infection success, though it had subtle effects on zoospore development time and reproductive output. This study shows that both immediate host and external environment as well as their interaction have significant effects on parasite fitness. Disentangling these effects improves our understanding of the processes underlying parasite spread and disease dynamics.

  7. Carp erythrodermatitis : host defense-pathogen interaction

    OpenAIRE

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense system. On the other hand, the host's resistance to a bacterial attack depends on its physiological state, the intensity of the bacterial attack and the efficacy of the defense system to ...

  8. Future Road Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  9. The vaginal microbiota, host defence and reproductive physiology

    Science.gov (United States)

    Smith, Steven B

    2016-01-01

    Abstract The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture‐independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive‐aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic‐acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non‐Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine‐tuned interaction is key to maintaining women's reproductive health. PMID:27373840

  10. The vaginal microbiota, host defence and reproductive physiology.

    Science.gov (United States)

    Smith, Steven B; Ravel, Jacques

    2017-01-15

    The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture-independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive-aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic-acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non-Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine-tuned interaction is key to maintaining women's reproductive health. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  11. Achieving maximum baryon densities

    International Nuclear Information System (INIS)

    Gyulassy, M.

    1984-01-01

    In continuing work on nuclear stopping power in the energy range E/sub lab/ approx. 10 GeV/nucleon, calculations were made of the energy and baryon densities that could be achieved in uranium-uranium collisions. Results are shown. The energy density reached could exceed 2 GeV/fm 3 and baryon densities could reach as high as ten times normal nuclear densities

  12. The effect of initial density and parasitoid intergenerational survival rate on classical biological control

    International Nuclear Information System (INIS)

    Xiao Yanni; Tang Sanyi

    2008-01-01

    Models of biological control have a long history of theoretical development that have focused on the interaction of a parasitoid and its host. The host-parasitoid systems have identified several important and general factors affecting the long-term dynamics of interacting populations. However, much less is known about how the initial densities of host-parasitoid populations affect the biological control as well as the stability of host-parasitoid systems. To do this, the classical Nicholson-Bailey model with host self-regulation and parasitoid intergenerational survival rate is used to uncover the effect of initial densities on the successful biological control. The results indicate that the simplest Nicholson-Bailey model has various coexistence with a wide range of parameters, including boundary attractors where the parasitoid population is absent and interior attractors where host-parasitoid coexists. The final stable states of host-parasitoid populations depend on their initial densities as well as their ratios, and those results are confirmed by basins of attraction of initial densities. The results also indicate that the parasitoid intergenerational survival rate increases the stability of the host-parasitoid systems. Therefore, the present research can help us to further understand the dynamical behavior of host-parasitoid interactions, to improve the classical biological control and to make management decisions

  13. Crowding and Density

    Science.gov (United States)

    Design and Environment, 1972

    1972-01-01

    Three-part report pinpointing problems and uncovering solutions for the dual concepts of density (ratio of people to space) and crowding (psychological response to density). Section one, A Primer on Crowding,'' reviews new psychological and social findings; section two, Density in the Suburbs,'' shows conflict between status quo and increased…

  14. Implicit and explicit host effects on excitons in pentacene derivatives

    Science.gov (United States)

    Charlton, R. J.; Fogarty, R. M.; Bogatko, S.; Zuehlsdorff, T. J.; Hine, N. D. M.; Heeney, M.; Horsfield, A. P.; Haynes, P. D.

    2018-03-01

    An ab initio study of the effects of implicit and explicit hosts on the excited state properties of pentacene and its nitrogen-based derivatives has been performed using ground state density functional theory (DFT), time-dependent DFT, and ΔSCF. We observe a significant solvatochromic redshift in the excitation energy of the lowest singlet state (S1) of pentacene from inclusion in a p-terphenyl host compared to vacuum; for an explicit host consisting of six nearest neighbour p-terphenyls, we obtain a redshift of 65 meV while a conductor-like polarisable continuum model (CPCM) yields a 78 meV redshift. Comparison is made between the excitonic properties of pentacene and four of its nitrogen-based analogs, 1,8-, 2,9-, 5,12-, and 6,13-diazapentacene with the latter found to be the most distinct due to local distortions in the ground state electronic structure. We observe that a CPCM is insufficient to fully understand the impact of the host due to the presence of a mild charge-transfer (CT) coupling between the chromophore and neighbouring p-terphenyls, a phenomenon which can only be captured using an explicit model. The strength of this CT interaction increases as the nitrogens are brought closer to the central acene ring of pentacene.

  15. IMPROVED SPECTROSCOPIC PARAMETERS FOR TRANSITING PLANET HOSTS

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Guillermo; Holman, Matthew J.; Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Sozzetti, Alessandro [INAF-Osservatorio Astronomico di Torino, I-10025 Pino Torinese (Italy); Buchhave, Lars A. [Niels Bohr Institute, Copenhagen University, DK-2100 Copenhagen (Denmark); Winn, Joshua N., E-mail: gtorres@cfa.harvard.edu [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2012-10-01

    We report homogeneous spectroscopic determinations of the effective temperature, metallicity, and projected rotational velocity for the host stars of 56 transiting planets. Our analysis is based primarily on the stellar parameter classification (SPC) technique. We investigate systematic errors by examining subsets of the data with two other methods that have often been used in previous studies (Spectroscopy Made Easy (SME) and MOOG). The SPC and SME results, both based on comparisons between synthetic spectra and actual spectra, show strong correlations between T{sub eff}, [Fe/H], and log g when solving for all three quantities simultaneously. In contrast the MOOG results, based on a more traditional curve-of-growth approach, show no such correlations. To combat the correlations and improve the accuracy of the temperatures and metallicities, we repeat the SPC analysis with a constraint on log g based on the mean stellar density that can be derived from the analysis of the transit light curves. Previous studies that have not taken advantage of this constraint have been subject to systematic errors in the stellar masses and radii of up to 20% and 10%, respectively, which can be larger than other observational uncertainties, and which also cause systematic errors in the planetary mass and radius.

  16. Environmental predictors of shrubby cinquefoil (Dasiphora fruticosa) habitat and quality as host for Maine’s endangered Clayton’s copper butterfly (Lycaena dorcas claytoni)

    Science.gov (United States)

    Drahovzal, Sarah A.; Loftin, Cynthia S.; Rhymer, Judith

    2015-01-01

    Population size of habitat-specialized butterflies is limited in part by host plant distribution and abundance. Effective conservation for host-specialist species requires knowledge of host-plant habitat conditions and relationships with the specialist species. Clayton’s copper butterfly (Lycaena dorcas claytoni) is a Maine state-endangered species that relies exclusively on shrubby cinquefoil (Dasiphora fruticosa) as its host. Dasiphora fruticosa occurs in 28 wetlands in Maine, ten of which are occupied by L. d. claytoni. Little is known about environmental conditions that support large, persistent stands of D. fruticosa in Maine. We evaluated the environment (hydrology, pore water and peat nutrients) associated with D. fruticosa distribution, age, and condition in Maine wetlands supporting robust stands of D. fruticosa to compare with L. d. claytoni occurrence. Although dominant water source in D. fruticosa—containing wetlands included both groundwater discharge and surface-flow, D. fruticosa coverage was greater in wetlands with consistent growing season water levels that dropped into or below the root zone by late season, and its distributions within wetlands reflected pore water hydrogen ion and conductivity gradients. Flooding magnitude and duration were greatest during the L.d. claytoni larval feeding period, whereas, mean depth to water table and upwelling increased and were most variable following the L. d. claytoni egg-laying period that precedes D. fruticosa senescence. Oldest sampled shrubs were 37 years, and older shrubs were larger and slower-growing. Encounter rates of L. d. claytoni were greater in wetlands with larger D. fruticosa plants of intermediate age and greater bloom density. Wetland management that combines conditions associated with D. fruticosa abundance (e.g., non-forested, seasonally consistent water levels with high conductivity) and L. d. claytoni occurrence (e.g., drawdown below the root zone following egg-laying, abundant

  17. Host evasion by Burkholderia cenocepacia

    Directory of Open Access Journals (Sweden)

    Shyamala eGanesan

    2012-01-01

    Full Text Available Burkholderia cenocepacia is an opportunistic respiratory pathogen of individuals with cystic fibrosis (CF. It is one of the highly transmissible species of Burkholderia cepacia complex and very resistant to almost all the antibiotics. Approximately 1/3rd of B. cenocepacia infected CF patients go on to develop fatal ‘cepacia syndrome’. During the last two decades, substantial progress has been made with regards to evasion of host innate defense mechanisms by B. cenocepacia. Almost all strains of B. cenocepacia has capacity to survive and replicate intracellularly in both airway epithelial cells and macrophages, which are primary centennials of the lung and play a pivotal role in clearance of infecting bacteria. Some strains of B. cenocepaica, which express cable pili and the associated 22kDa adhesin are also capable of transmigrating across airway epithelium and persist in mouse models of infection. In this review, we will discuss how this type of interaction between B. cenocepacia and host may lead to persistence of bacteria and contribute to lung inflammation in CF patients.

  18. Forragem hidropônica de milheto: produção e qualidade nutricional em diferentes densidades de semeadura e idades de colheita Hydroponic millet forage: production and naurishing quality in different sowing densities and harvest ages

    Directory of Open Access Journals (Sweden)

    Liziany Müller

    2006-08-01

    Full Text Available Com objetivo de avaliar a produtividade e a qualidade nutricional da forragem hidropônica de milheto, realizou-se um experimento no Departamento de Fitotecnia da Universidade Federal de Santa Maria (UFSM - RS, identificando a densidade adequada de sementes e a idade ideal de colheita. Adotou-se o delineamento experimental inteiramente casualizado; os tratamentos foram distribuídos em esquema fatorial 4x2, constituídos por quatro densidades de semeadura (0,5, 1,0, 1,5 e 2,0kg m-2 e duas colheitas (10 e 20 dias. Não foi observada significância à interação densidade x idade de colheita para nenhuma das variáveis analisadas. A estatura, a fitomassa seca, a hemicelulose e a lignina não foram influenciadas pela densidade de semeadura. O aumento da densidade de semeadura promoveu incremento na fitomassa fresca e no teor de proteína bruta e redução nos teores de fibra em detergente neutro e ácido e em celulose. A colheita aos 10 dias permitiu maiores valores de fitomassa fresca e seca, de hemicelulose, de celulose e menores valores de fibra em detergente neutro e ácido, e de lignina. Em relação à proteína bruta, não foi observada diferença significativa para as colheitas aos 10 e 20 dias. Pode-se sugerir o cultivo da forragem hidropônica de milheto, com densidade de semeadura de 2kg m-2, e colheita aos 10 dias, para se obter boa produção com qualidade nutricional.This study aimed to evaluate the effect of different harvest dates and sowing densities on growth and bromatological composition of hydroponic millet forage. The experiment was carried out in the Crop Production of the Universidade Federal of Santa Maria, RS, Brazil. A randomized experimental design was used. Treatments consisted of four sowing densities (0.5, 1.0, 1.5 e 2.0kg seed m-2 and two harvest dates (10 and 20 days after germination distributed in a 4x2 factorial scheme. There was no interaction between sowing densities and harvest date for all analyzed variables

  19. MRI of the normal brain from early childhood to middle age. Pt. 1. Appearances on T2- and proton density-weighted images and occurrence of incidental high-signal foci

    International Nuclear Information System (INIS)

    Autti, T.; Raininko, R.; Vanhanen, S.L.; Kallio, M.; Santavuori, P.

    1994-01-01

    The magnetic resonance images of 67 healthy subjects aged 4-50 years were studied for differences in general signal intensity between the different brain structures, the frequency of focal intensity changes in the brain, and variations in size of the cerebrospinal fluid (CSF) spaces. In adults over 25 years of age the thalamus gave lower signal than the putamen or caudate nucleus. Definite periventricular high signal was found in the white matter of one third of subjects of all ages. Small (< 5 mm in diameter) high signal foci were found in the cerebral white matter on T2-weighted images in 27 % of subjects (20 % of healthy children and adolescents and 34 % of adults). They gave high signal on both short and long echoes in 11 % of children and adolescents and in 22 % of adults; 51 % of all foci gave high signal with both echoes. This does not support the hypothesis that they are caused mainly by enlarged Virchow-Robin spaces. Of the high signal foci on T2-weighted images, 86 % were in watershead areas. Two foci were found in one subject in the periventricular watershed area (beside the tips of the frontal horns) and they were never seen in the other deep white matter regions. In healthy, relatively young subjects with no known risk factors, high signal foci other than Virchow-Robin spaces, were common; neither their prevalence nor their number correlated with age in this series. A few slightly large sulci were found in some adults. (orig.)

  20. Short Adolescents Born Small for Gestational Age : Gonadal and thyroid function, bone mineral density, quality of life and adult height: The effects of growth hormone and additional postponement of puberty

    NARCIS (Netherlands)

    A.J. Lem (Annemieke)

    2012-01-01

    textabstractFrom 1991, our research group and others have been investigating children with short stature who were born small for gestational age (SGA), both before and during treatment with biosynthetic growth hormone (GH). In 2005, GH treatment was licensed for short SGA children in the

  1. Host feeding in insect parasitoids: why destructively feed upon a host that excretes an alternative?

    NARCIS (Netherlands)

    Burger, J.S.M.; Reijnen, T.M.; Van Lenteren, J.C.; Vet, L.E.M.

    2004-01-01

    Host feeding is the consumption of host tissue by the adult female parasitoid. We studied the function of destructive host feeding and its advantage over non-destructive feeding on host-derived honeydew in the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). We allowed

  2. Probability densities and Lévy densities

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler

    For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated.......For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated....

  3. Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host.

    Science.gov (United States)

    Amarillo-Suárez, A; Repizo, A; Robles, J; Diaz, J; Bustamante, S

    2017-08-01

    The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.

  4. InGaAs Quantum Dots on Cross-Hatch Patterns as a Host for Diluted Magnetic Semiconductor Medium

    Directory of Open Access Journals (Sweden)

    Teeravat Limwongse

    2013-01-01

    Full Text Available Storage density on magnetic medium is increasing at an exponential rate. The magnetic region that stores one bit of information is correspondingly decreasing in size and will ultimately reach quantum dimensions. Magnetic quantum dots (QDs can be grown using semiconductor as a host and magnetic constituents added to give them magnetic properties. Our results show how molecular beam epitaxy and, particularly, lattice-mismatched heteroepitaxy can be used to form laterally aligned, high-density semiconducting host in a single growth run without any use of lithography or etching. Representative results of how semiconductor QD hosts arrange themselves on various stripes and cross-hatch patterns are reported.

  5. The ecology of fish parasites with particular reference to helminth parasites and their salmonid fish hosts in Welsh rivers: a review of some of the central questions.

    Science.gov (United States)

    Thomas, J D

    2002-01-01

    Ecological studies carried out in Welsh rivers on the feeding behaviour of salmonid fish, their helminth parasites and intermediate hosts in the early 1950s and in 1998 have been used as a basis to review the literature dealing with the following questions. First, how are the helminth populations dispersed in space-time? Second, to what extent are the distributional patterns and the life history strategies of the parasites influenced by physicochemical factors? Third, to what extent are populations of helmith parasites in salmonid fish influenced by host characteristics including the genome, sex, age, size, social position and Feeding behaviour? Fourth, are the populations of parasites regulated in a density-dependent manner? Fifth, do the parasites influence the survival and wellbeing of their salmonid hosts and the evolution of sex? Sixth, to what extent is the parasite community influenced by environmental changes including those of an anthropogenic nature and can the parasites be used as bioindicators of pollution? As with most parasites the helminth species found were highly overdispersed thus making it necessary to undertake a log10 (1 + x) conversion for statistical analyses. Statistical analyses confirm that the genome, age and sex of salmonid fish hosts, the station and seasonal change in radiation levels were significant factors in predicting the number of parasites. The evidence given supports the hypothesis that the feeding behaviour and habitat selection by the host fish, their position in the social hierarchy and the overdispersed nature of the transmission sites are the key factors in causing differences in the parasitic fauna related to host species, age, size and sex. Differences in the helminth parasite community related to station can be explained on the basis of differences in water types, sediments and chemistry. Although the evidence presented is in accord with the consensus view that temperature is correlated with seasonal changes in the

  6. Novel association of the R230C variant of the ABCA1 gene with high triglyceride levels and low high-density lipoprotein cholesterol levels in Mexican school-age children with high prevalence of obesity.

    Science.gov (United States)

    Gamboa-Meléndez, Marco Alberto; Galindo-Gómez, Carlos; Juárez-Martínez, Liliana; Gómez, F Enrique; Diaz-Diaz, Eulises; Ávila-Arcos, Marco Antonio; Ávila-Curiel, Abelardo

    2015-08-01

    Metabolic syndrome (MetS) is a disorder that includes a cluster of several risk factors for the development of type 2 diabetes and cardiovascular disease. The R230C variant of the ABCA1 gene has been associated with low HDL-cholesterol in several studies, but its association with MetS in children remains to be determined. The aim of this study was to analyze the association of the R230C variant with MetS and other metabolic traits in school-aged Mexican children. The study was performed in seven urban primary schools in the State of Mexico. Four hundred thirty-two Mexican school-age children 6-13 years old were recruited. MetS was identified using the International Diabetes Federation definition. The R230C variant of the ABCA1 gene was genotyped to seek associations with MetS and other metabolic traits. The prevalence of MetS was 29% in children aged 10-13 years. The R230C variant was not associated with MetS (OR = 1.65; p = 0.139). Furthermore, in the whole population, the R230C variant was associated with low HDL-cholesterol levels (β coefficient = -3.28, p <0.001). Interestingly, in the total population we found a novel association of this variant with high triglyceride levels (β coefficient = 14.34; p = 0.027). We found a new association of the R230C variant of the ABCA1 gene with high triglyceride levels. Our findings also replicate the association of this variant with low HDL-cholesterol levels in Mexican school-age children. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

  7. Lithium deposits hosted in intracontinental rhyolite calderas

    Science.gov (United States)

    Benson, T. R.; Coble, M. A.; Mahood, G. A.

    2017-12-01

    Lithium (Li) is classified as a technology-critical element due to the increasing demand for Li-ion batteries, which have a high power density and a relatively low cost that make them optimal for energy storage in mobile electronics, the electrical power grid, and hybrid and electric vehicles. Given that many projections for Li demand exceed current economic reserves and the market is dominated by Australia and Chile, discovery of new domestic Li resources will help diversify the supply chain and keep future technology costs down. Here we show that lake sediments preserved within intracontinental rhyolite calderas have the potential to host Li deposits on par with some of the largest Li brine deposits in the world. We compare Li concentrations of rhyolite magmas formed in a variety of tectonic settings using in situ SHRIMP-RG measurements of homogenized quartz-hosted melt inclusions. Rhyolite magmas that formed within thick, felsic continental crust (e.g., Yellowstone and Hideaway Park, United States) display moderate to extreme Li enrichment (1,500 - 9,000 ppm), whereas magmas formed in thin crust or crust comprised of accreted arc terranes (e.g., Pantelleria, Italy and High Rock, Nevada) contain Li concentrations less than 500 ppm. When the Li-enriched magmas erupt to form calderas, the cauldron depression serves as an ideal catchment within which meteoric water that leached Li from intracaldera ignimbrite, nearby outflow ignimbrite, and caldera-related lavas can accumulate. Additional Li is concentrated in the system through near-neutral, low-temperature hydrothermal fluids circulated along ring fractures as remnant magma solidifies and degasses. Li-bearing hectorite and illite clays form in this alteration zone, and when preserved in the geological record, can lead to a large Li deposit like the 2 Mt Kings Valley Li deposit in the McDermitt Caldera, Nevada. Because more than 100 large Cenozoic calderas occur in the western United States that formed on eruption

  8. Why Density Dependent Propulsion?

    Science.gov (United States)

    Robertson, Glen A.

    2011-01-01

    In 2004 Khoury and Weltman produced a density dependent cosmology theory they call the Chameleon, as at its nature, it is hidden within known physics. The Chameleon theory has implications to dark matter/energy with universe acceleration properties, which implies a new force mechanism with ties to the far and local density environment. In this paper, the Chameleon Density Model is discussed in terms of propulsion toward new propellant-less engineering methods.

  9. Density limits in Tokamaks

    International Nuclear Information System (INIS)

    Tendler, M.

    1984-06-01

    The energy loss from a tokamak plasma due to neutral hydrogen radiation and recycling is of great importance for the energy balance at the periphery. It is shown that the requirement for thermal equilibrium implies a constraint on the maximum attainable edge density. The relation to other density limits is discussed. The average plasma density is shown to be a strong function of the refuelling deposition profile. (author)

  10. Nuclear Level Densities

    International Nuclear Information System (INIS)

    Grimes, S.M.

    2005-01-01

    Recent research in the area of nuclear level densities is reviewed. The current interest in nuclear astrophysics and in structure of nuclei off of the line of stability has led to the development of radioactive beam facilities with larger machines currently being planned. Nuclear level densities for the systems used to produce the radioactive beams influence substantially the production rates of these beams. The modification of level-density parameters near the drip lines would also affect nucleosynthesis rates and abundances

  11. Measurement of true density

    International Nuclear Information System (INIS)

    Carr-Brion, K.G.; Keen, E.F.

    1982-01-01

    System for determining the true density of a fluent mixture such as a liquid slurry, containing entrained gas, such as air comprises a restriction in pipe through which at least a part of the mixture is passed. Density measuring means such as gamma-ray detectors and source measure the apparent density of the mixture before and after its passage through the restriction. Solid-state pressure measuring devices are arranged to measure the pressure in the mixture before and after its passage through the restriction. Calculating means, such as a programmed microprocessor, determine the true density from these measurements using relationships given in the description. (author)

  12. Aging Brain, Aging Mind.

    Science.gov (United States)

    Selkoe, Dennis J.

    1992-01-01

    Discusses the aging process related to physical changes of the human neural structure involved in learning, memory, and reasoning. Presents evidence that indicates such alterations do not necessarily signal the decline in cognitive function. Vignettes provide images of brain structures involved in learning, memory, and reasoning; hippocampal…

  13. Control strategies for a stochastic model of host-parasite interaction in a seasonal environment.

    Science.gov (United States)

    Gómez-Corral, A; López García, M

    2014-08-07

    We examine a nonlinear stochastic model for the parasite load of a single host over a predetermined time interval. We use nonhomogeneous Poisson processes to model the acquisition of parasites, the parasite-induced host mortality, the natural (no parasite-induced) host mortality, and the reproduction and death of parasites within the host. Algebraic results are first obtained on the age-dependent distribution of the number of parasites infesting the host at an arbitrary time t. The interest is in control strategies based on isolation of the host and the use of an anthelmintic at a certain intervention instant t0. This means that the host is free living in a seasonal environment, and it is transferred to a uninfected area at age t0. In the uninfected area, the host does not acquire new parasites, undergoes a treatment to decrease the parasite load, and its natural and parasite-induced mortality are altered. For a suitable selection of t0, we present two control criteria that appropriately balance effectiveness and cost of intervention. Our approach is based on simple probabilistic principles, and it allows us to examine seasonal fluctuations of gastrointestinal nematode burden in growing lambs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Host-to-host variation of ecological interactions in polymicrobial infections

    Science.gov (United States)

    Mukherjee, Sayak; Weimer, Kristin E.; Seok, Sang-Cheol; Ray, Will C.; Jayaprakash, C.; Vieland, Veronica J.; Swords, W. Edward; Das, Jayajit

    2015-02-01

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

  15. Host-to-host variation of ecological interactions in polymicrobial infections.

    Science.gov (United States)

    Mukherjee, Sayak; Weimer, Kristin E; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Swords, W Edward; Das, Jayajit

    2014-12-04

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

  16. Local host specialization, host-switching, and dispersal shape the regional distributions of avian haemosporidian parasites.

    Science.gov (United States)

    Ellis, Vincenzo A; Collins, Michael D; Medeiros, Matthew C I; Sari, Eloisa H R; Coffey, Elyse D; Dickerson, Rebecca C; Lugarini, Camile; Stratford, Jeffrey A; Henry, Donata R; Merrill, Loren; Matthews, Alix E; Hanson, Alison A; Roberts, Jackson R; Joyce, Michael; Kunkel, Melanie R; Ricklefs, Robert E

    2015-09-08

    The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.

  17. Bacterial pathogen manipulation of host membrane trafficking.

    Science.gov (United States)

    Asrat, Seblewongel; de Jesús, Dennise A; Hempstead, Andrew D; Ramabhadran, Vinay; Isberg, Ralph R

    2014-01-01

    Pathogens use a vast number of strategies to alter host membrane dynamics. Targeting the host membrane machinery is important for the survival and pathogenesis of several extracellular, vacuolar, and cytosolic bacteria. Membrane manipulation promotes bacterial replication while suppressing host responses, allowing the bacterium to thrive in a hostile environment. This review provides a comprehensive summary of various strategies used by both extracellular and intracellular bacteria to hijack host membrane trafficking machinery. We start with mechanisms used by bacteria to alter the plasma membrane, delve into the hijacking of various vesicle trafficking pathways, and conclude by summarizing bacterial adaptation to host immune responses. Understanding bacterial manipulation of host membrane trafficking provides insights into bacterial pathogenesis and uncovers the molecular mechanisms behind various processes within a eukaryotic cell.

  18. Road MAPs to engineer host microbiomes.

    Science.gov (United States)

    Oyserman, Ben O; Medema, Marnix H; Raaijmakers, Jos M

    2017-12-02

    Microbiomes contribute directly or indirectly to host health and fitness. Thus far, investigations into these emergent traits, referred to here as microbiome-associated phenotypes (MAPs), have been primarily qualitative and taxonomy-driven rather than quantitative and trait-based. We present the MAPs-first approach, a theoretical and experimental roadmap that involves quantitative profiling of MAPs across genetically variable hosts and subsequent identification of the underlying mechanisms. We outline strategies for developing 'modular microbiomes'-synthetic microbial consortia that are engineered in concert with the host genotype to confer different but mutually compatible MAPs to a single host or host population. By integrating host and microbial traits, these strategies will facilitate targeted engineering of microbiomes to the benefit of agriculture, human/animal health and biotechnology. Copyright © 2017. Published by Elsevier Ltd.

  19. Microphallids in Gammarus insensibilis Stock, 1966 from a Black Sea lagoon: host response to infection.

    Science.gov (United States)

    Kostadinova, A; Mavrodieva, R S

    2005-09-01

    We examined the patterns of parasite melanization in Gammarus insensibilis using data on microphallids from Pomorie Lagoon (Black Sea) in the light of 3 predictions associated with host survival: (i) hosts invest more in defence in an environment where the likelihood for infection is higher; (ii) multiple immune challenges exhaust host reserves and result in decreased melanization rates in older hosts; (iii) host immune response is directed against the cerebral metacercariae of Microphallus papillorobustus that alter amphipod behaviour and are most detrimental to the host. G. insensibilis was capable of melanizing the metacercariae of all four species of trematodes found to be hosted by the amphipods. The frequency of melanization and mean abundance of melanized metacercariae were substantially higher than those observed in the same amphipod-gammarid system on the French Mediterranean coast. However, the rate of melanization was low and showed a significant decrease with amphipod size. Although the 4 species were differentially melanized, the host response was largely directed against Microphallus hoffmanni and M. subdolum. We suggest that (i) the lower melanization efficiency with age is due to the mode of infection, probably leading to loss of haemolymph and monopolization of the defence resources for wound healing and (ii) in the French system, host response focuses on the most prevalent and abundant species.

  20. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

    Science.gov (United States)

    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

    Wolbachia pipientis , a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia -mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens , and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus , we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia -mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

  1. Plasticity in host utilization by two host-associated populations of Aphis gossypii Glover.

    Science.gov (United States)

    Barman, A K; Gadhave, K R; Dutta, B; Srinivasan, R

    2018-06-01

    Biological and morphological plasticity in polyphagous insect herbivores allow them to exploit diverse host plant species. Geographical differences in resource availability can lead to preferential host exploitation and result in inconsistent host specialization. Biological and molecular data provide insights into specialization and plasticity of such herbivore populations. In agricultural landscapes, Aphis gossypii encounters several crop and non-crop hosts, which exist in temporal and spatial proximity. We investigated the host-specialization of two A. gossypii host-associated populations (HAPs), which were field collected from cotton and squash (cotton-associated population and melon-associated population), and later maintained separately in the greenhouse. The two aphid populations were exposed to seven plant species (cotton, okra, watermelon, squash, cucumber, pigweed, and morning glory), and evaluated for their host utilization plasticity by estimating aphid's fitness parameters (nymphal period, adult period, fecundity, and intrinsic rate of increase). Four phenotypical characters (body length, head capsule width, hind tibia length and cornicle length) were also measured from the resulting 14 different HAP × host plant combinations. Phylogenetic analysis of mitochondrial COI sequences showed no genetic variation between the two HAPs. Fitness parameters indicated a significant variation between the two aphid populations, and the variation was influenced by host plants. The performance of melon-aphids was poor (up to 89% reduction in fecundity) on malvaceous hosts, cotton and okra. However, cotton-aphids performed better on cucurbitaceous hosts, squash and watermelon (up to 66% increased fecundity) compared with the natal host, cotton. Both HAPs were able to reproduce on two weed hosts. Cotton-aphids were smaller than melon-aphids irrespective of their host plants. Results from this study suggest that the two HAPs in the study area do not have strict host

  2. KEPLER EXOPLANET CANDIDATE HOST STARS ARE PREFERENTIALLY METAL RICH

    International Nuclear Information System (INIS)

    Schlaufman, Kevin C.; Laughlin, Gregory

    2011-01-01

    We find that Kepler exoplanet candidate (EC) host stars are preferentially metal rich, including the low-mass stellar hosts of small-radius ECs. The last observation confirms a tentative hint that there is a correlation between the metallicity of low-mass stars and the presence of low-mass and small-radius exoplanets. In particular, we compare the J-H-g-r color-color distribution of Kepler EC host stars with a control sample of dwarf stars selected from the ∼150, 000 stars observed during Q1 and Q2 of the Kepler mission but with no detected planets. We find that at J - H = 0.30 characteristic of solar-type stars, the average g-r color of stars that host giant ECs is 4σ redder than the average color of the stars in the control sample. At the same J - H color, the average g-r color of solar-type stars that host small-radius ECs is indistinguishable from the average color of the stars in the control sample. In addition, we find that at J - H = 0.62 indicative of late K dwarfs, the average g-r color of stars that host small-radius ECs is 4σ redder than the average color of the stars in the control sample. These offsets are unlikely to be caused by differential reddening, age differences between the two populations, or the presence of giant stars in the control sample. Stellar models suggest that the first color offset is due to a 0.2 dex enhancement in [Fe/H] of the giant EC host population at M * ∼ 1 M sun , while Sloan photometry of M 67 and NGC 6791 suggests that the second color offset is due to a similar [Fe/H] enhancement of the small-radius EC host population at M * ∼ 0.7 M sun . These correlations are a natural consequence of the core-accretion model of planet formation.

  3. Effects of Helicoverpa armigera (Noctuidae, Lepidoptera) host stages on some developmental parameters of the uniparental endoparasitoid Meteorus pulchricornis (Braconidae, Hymenoptera).

    Science.gov (United States)

    Liu, Ya-Hui; Li, Bao-Ping

    2008-04-01

    A single choice test was performed to examine developmental strategies in the uniparental endoparasitoid Meteorus pulchricornis and its host, the cotton bollworm Helicoverpa armigera. The results support the dome-shaped model in which the fitness functions are 'dome-shaped' relative to size (and age) of host at parasitism. Older and, hence, larger host larvae were simply not better hosts for the developing parasitoids. Although parasitoid size (measured as cocoon weight and adult hind tibia length) was positively correlated with host instars at parasitism, parasitoids developing in larger hosts (L5 and L6) suffered much higher mortality than conspecifics developing in smaller hosts (L2-L4). Furthermore, egg-to-adult development time in M. pulchricornis was significantly longer in older host larvae (L4-L6) than in the younger. Performance of M. pulchricornis, as indicated by fitness-related traits, strongly suggests that the L3 host is the most suitable for survival, growth and development of the parasitoid, followed by both L2 and L4 hosts; whereas, L1, L5 and L6 are the least favourable hosts. The oviposition tendency of M. pulchricornis, represented by parasitism level, was not perfectly consistent with the performance of the offspring; L2-L4 hosts, although with the same parasitism level, had offspring parasitoids with differences in fitness-related performance. Larval development in Helicoverpa armigera was usually suspended, but occasionally advanced, in the final instar.

  4. On density forecast evaluation

    NARCIS (Netherlands)

    Diks, C.

    2008-01-01

    Traditionally, probability integral transforms (PITs) have been popular means for evaluating density forecasts. For an ideal density forecast, the PITs should be uniformly distributed on the unit interval and independent. However, this is only a necessary condition, and not a sufficient one, as

  5. HOST GALAXY IDENTIFICATION FOR SUPERNOVA SURVEYS

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; Spinka, Harold; Kessler, Richard; Goldstein, Daniel A.; Liotine, Camille; Pomian, Katarzyna; D’Andrea, Chris B.; Sullivan, Mark; Carretero, Jorge; Castander, Francisco J.; Nichol, Robert C.; Finley, David A.; Fischer, John A.; Foley, Ryan J.; Kim, Alex G.; Papadopoulos, Andreas; Sako, Masao; Scolnic, Daniel M.; Smith, Mathew; Tucker, Brad E.; Uddin, Syed; Wolf, Rachel C.; Yuan, Fang; Abbott, Tim M. C.; Abdalla, Filipe B.; Benoit-Lévy, Aurélien; Bertin, Emmanuel; Brooks, David; Rosell, Aurelio Carnero; Kind, Matias Carrasco; Cunha, Carlos E.; Costa, Luiz N. da; Desai, Shantanu; Doel, Peter; Eifler, Tim F.; Evrard, August E.; Flaugher, Brenna; Fosalba, Pablo; Gaztañaga, Enrique; Gruen, Daniel; Gruendl, Robert; James, David J.; Kuehn, Kyler; Kuropatkin, Nikolay; Maia, Marcio A. G.; Marshall, Jennifer L.; Miquel, Ramon; Plazas, Andrés A.; Romer, A. Kathy; Sánchez, Eusebio; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Sobreira, Flávia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Walker, Alistair R.; Wester, William

    2016-11-08

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

  6. Host plant adaptation in Drosophila mettleri populations.

    Directory of Open Access Journals (Sweden)

    Sergio Castrezana

    Full Text Available The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total. We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp. in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts.

  7. HOST GALAXY IDENTIFICATION FOR SUPERNOVA SURVEYS

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; Spinka, Harold; Liotine, Camille; Pomian, Katarzyna [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Kessler, Richard; Scolnic, Daniel M. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Goldstein, Daniel A. [Department of Astronomy, University of California, Berkeley, 501 Campbell Hall #3411, Berkeley, CA 94720 (United States); D’Andrea, Chris B.; Nichol, Robert C.; Papadopoulos, Andreas [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Sullivan, Mark [Department of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Carretero, Jorge; Castander, Francisco J. [Institut de Ciències de l’Espai, IEEC-CSIC, Campus UAB, Carrer de Can Magrans, s/n, E-08193 Bellaterra, Barcelona (Spain); Finley, David A. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Fischer, John A.; Sako, Masao [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Foley, Ryan J. [Department of Astronomy, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Kim, Alex G., E-mail: raviryan@gmail.com [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); and others

    2016-12-01

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate “hostless” SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

  8. Learning Grasp Affordance Densities

    DEFF Research Database (Denmark)

    Detry, Renaud; Kraft, Dirk; Kroemer, Oliver

    2011-01-01

    and relies on kernel density estimation to provide a continuous model. Grasp densities are learned and refined from exploration, by letting a robot “play” with an object in a sequence of graspand-drop actions: The robot uses visual cues to generate a set of grasp hypotheses; it then executes......We address the issue of learning and representing object grasp affordance models. We model grasp affordances with continuous probability density functions (grasp densities) which link object-relative grasp poses to their success probability. The underlying function representation is nonparametric...... these and records their outcomes. When a satisfactory number of grasp data is available, an importance-sampling algorithm turns these into a grasp density. We evaluate our method in a largely autonomous learning experiment run on three objects of distinct shapes. The experiment shows how learning increases success...

  9. Leptin and bone mineral density

    DEFF Research Database (Denmark)

    Morberg, Cathrine M.; Tetens, Inge; Black, Eva

    2003-01-01

    Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg...... males, but it also stresses the fact that the strong covariation between the examined variables is a shortcoming of the cross-sectional design....

  10. Host-to-host variation of ecological interactions in polymicrobial infections

    International Nuclear Information System (INIS)

    Mukherjee, Sayak; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Das, Jayajit; Weimer, Kristin E; Swords, W Edward

    2015-01-01

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host–microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species. (paper)

  11. A host phase for the disposal of weapons plutonium

    International Nuclear Information System (INIS)

    Lutze, Werner; Helean, K.B.; Gong, W.L.; Ewing, Rodney C.

    1999-01-01

    Research was conducted into the possible use of zircon (ZrSiO 4 ) as a host phase for storage or disposal of excess weapons plutonium. Zircon is one of the most chemically durable minerals. Its structure can accommodate a variety of elements, including plutonium and uranium. Natural zircon contains uranium and thorium together in different quantities, usually in the range of less than one weight percent up to several weight percent. Zircon occurs in nature as a crystalline or a partially to fully metamict mineral, depending on age and actinide element concentration, i.e., on radiation damage. These zircon samples have been studied extensively and the results are documented in the literature in terms of radiation damage to the crystal structure and related property changes, e.g., density, hardness, loss of uranium and lead, etc. Thus, a unique suite of natural analogues are available to describe the effect of decay of 239 Pu on zircon's structure and how zircon's physical and chemical properties will be affected over very long periods of time. Actually, the oldest zircon samples known are over 3 billion years old. This period covers the time for decay of 239 Pu (half-life 24,300 yr.) and most of its daughter 235 U (half-life 700 million yr.). Because of its chemical durability, even under extreme geological conditions, zircon is the most widely used mineral for geochronological dating (7,000 publications). It is the oldest dated mineral on earth and in the universe. Zircon has already been doped with about 10 weight percent of plutonium. Pure PuSiO 4 has also been synthesized and has the same crystal structure as zircon. However, use of zircon as a storage medium or waste form for plutonium requires further materials characterization. Experiments can either be conducted in laboratories where plutonium can be handled or plutonium can be simulated by other elements, and experiments can be done under less restricted conditions. The authors conducted work with zircon

  12. LIFE CYCLE, DISTRIBUTION AND ABUNDANCE OF CARCINONEMERTES EPIALTI, A NEMERTEAN EGG PREDATOR OF THE SHORE CRAB, HEMIGRAPSUS OREGONENSIS, IN RELATION TO HOST SIZE, REPRODUCTION AND MOLT CYCLE.

    Science.gov (United States)

    Kuris, Armand M

    1978-02-01

    1. The geographic range of Carcinonemertes epialti has been greatly extended. The worms are found from Bahia San Quintin, Baja California, Mexico, to Page's Lagoon, Vancouver Island, British Columbia, Canada. 2. New host records for C. epialti include H. oregonensis, and H. nudus. It is rare on its type host Pugettia producta. Specimens of Carcinonemertes of uncertain affinities are also found on Cancer antennarius, C. anthonyi and C. productus. 3. Carcinonemertes epialti adults are egg predators on ovigerous hosts. Growth, demography and abundance are described in relation to the embryogenic stage of the host brood at Bodega Harbor, California. 4. Nonfeeding juveniles are ensheathed on individuals of both host sexes over 8.0 mm carapace width. 5. Transmission experiments show that contact transfer of juvenile nemerteans from males to other hosts may occur. 6. The percentage of infestation and mean density peak in autumn on H. oregonensis at Bodega Harbor. 7. Ovigerous female hosts are more frequently infested with C. epialti, particularly at small host sizes, than are male or nonovigerous female hosts at Bodega Harbor. However, average worm density on ovigerous females is low. 8. Mean density of C. epialti rises through late postmolt, declines during intermolt and rebuilds to a high level in late premolt H. oregonensisfrom Bodega Harbor. 9. Large crabs have a higher percentage of infestations and mean densities per infection than do small crabs. Nemerteans are more frequently found in the sternal-abdominal furrow and less frequently in the limb axillae on large crabs. 10. A model of C. epialti transmission and site occupancy is proposed, incorporating the influence of host size, sex, reproductive state, embryogenesis, molt cycle stage and molt cycle duration of H. oregonensis at Bodega Harbor. Site availability increases with host size. At higher densities the juvenile nemerteans increasingly occupy less preferred sites. Transferral of juvenile nemerteans occurs

  13. A randomized study of the prevention of acute graft-versus-host disease

    International Nuclear Information System (INIS)

    Ramsay, N.K.C.; Kersey, J.H.; Robison, L.L.; McGlave, P.B.; Woods, W.G.; Krivit, W.; Kim, T.H.; Goldman, A.I.; Nesbit, M.E. Jr.

    1982-01-01

    Acute graft-versus-host disease is a major problem in allogeneic bone-marrow transplantation. We performed a randomized study to compare the effectiveness of two regimens in the prevention of acute graft-versus-host disease. Thirty-five patients received methotrexate alone, and 32 received methotrexate, antithymocyte globulin, and prednisone. Of the patients who received methotrexate alone, 48 percent had acute graft-versus-host disease, as compared with 21 per cent of those who received methotrexate, antithymocyte globulin, and prednisone (P = 0.01). The age of the recipient was a significant factor in the development of acute graft-versus-host disease: Older patients had a higher incidence of the disease (P = 0.001). We conclude that the combination of methotrexate, antithymocyte globulin, and prednisone significantly decreased the incidence of acute graft-versus-host disease and should be used to prevent this disorder in patients receiving allogeneic marrow transplants

  14. Social host liability for minors and underage drunk-driving accidents.

    Science.gov (United States)

    Dills, Angela K

    2010-03-01

    Social host laws for minors aim to reduce teenage alcohol consumption by imposing liability on adults who host parties. Parents cite safety reasons as part of their motivation for hosting parties, preferring their teens and their teens' friends to drink in a supervised and safe locale. Both sides predict an effect of social host liability for minors on alcohol-related traffic accident rates for under-aged drinkers; the effects, however, work in opposite directions. This paper finds that, among 18-20 year olds, social host liability for minors reduced the drunk-driving fatality rate by 9%. I find no effect on sober traffic fatalities. Survey data on drinking and drunk driving suggest the declines resulted mostly from reductions in drunk driving and not reductions in drinking. Copyright 2009 Elsevier B.V. All rights reserved.

  15. Current density tensors

    Science.gov (United States)

    Lazzeretti, Paolo

    2018-04-01

    It is shown that nonsymmetric second-rank current density tensors, related to the current densities induced by magnetic fields and nuclear magnetic dipole moments, are fundamental properties of a molecule. Together with magnetizability, nuclear magnetic shielding, and nuclear spin-spin coupling, they completely characterize its response to magnetic perturbations. Gauge invariance, resolution into isotropic, deviatoric, and antisymmetric parts, and contributions of current density tensors to magnetic properties are discussed. The components of the second-rank tensor properties are rationalized via relationships explicitly connecting them to the direction of the induced current density vectors and to the components of the current density tensors. The contribution of the deviatoric part to the average value of magnetizability, nuclear shielding, and nuclear spin-spin coupling, uniquely determined by the antisymmetric part of current density tensors, vanishes identically. The physical meaning of isotropic and anisotropic invariants of current density tensors has been investigated, and the connection between anisotropy magnitude and electron delocalization has been discussed.

  16. Introduced pathogens follow the invasion front of a spreading alien host

    Science.gov (United States)

    Ann E. Hajek; Patrick C. Tobin

    2011-01-01

    When an invasive species first colonizes an area, there is an interval before any host-specific natural enemies arrive at the new location. Population densities of newly invading species are low, and the spatial and temporal interactions between spreading invasive species and specific natural enemies that follow are poorly understood. We measured infection rates of two...

  17. Assessment of wood density of seven clones of Eucalyptus grandis ...

    African Journals Online (AJOL)

    With the objective of evaluating the correlation of wood basic density with age in seven Eucalyptus grandis clones planted in Brazil, five trees in each clone were sampled at the ages of 0, 5, 1, 5, 2, 5, 3, 5, 4, 5 and 7, 5 years. The analysis of these samples showed that the intraclonal variation of the basic density (except for 0, ...

  18. Data from: Two different strategies of host manipulation allow parasites to persist in intermediate-definitive host systems

    NARCIS (Netherlands)

    Vries, de Lana; Langevelde, van F.

    2017-01-01

    Trophically-transmitted parasites start their development in an intermediate host, before they finish the development in their definitive host when the definitive host preys on the intermediate host. In intermediate-definitive host systems, two strategies of host manipulation have been evolved:

  19. Dynamical System and Nonlinear Regression for Estimate Host-Parasitoid Relationship

    Directory of Open Access Journals (Sweden)

    Ileana Miranda Cabrera

    2010-01-01

    Full Text Available The complex relationships of a crop with the pest, its natural enemies, and the climate factors exist in all the ecosystems, but the mathematic models has studied only some components to know the relation cause-effect. The most studied system has been concerned with the relationship pest-natural enemies such as prey-predator or host-parasitoid. The present paper shows a dynamical system for studying the relationship host-parasitoid (Diaphorina citri, Tamarixia radiata and shows that a nonlinear model permits the estimation of the parasite nymphs using nymphs healthy as the known variable. The model showed the functional answer of the parasitoid, in which a point arrives that its density is not augmented although the number host increases, and it becomes necessary to intervene in the ecosystem. A simple algorithm is used to estimate the parasitoids level using the priori relationship between the host and the climate factors and then the nonlinear model.

  20. Nestedness of ectoparasite-vertebrate host networks.

    Directory of Open Access Journals (Sweden)

    Sean P Graham

    2009-11-01

    Full Text Available Determining the structure of ectoparasite-host networks will enable disease ecologists to better understand and predict the spread of vector-borne diseases. If these networks have consistent properties, then studying the structure of well-understood networks could lead to extrapolation of these properties to others, including those that support emerging pathogens. Borrowing a quantitative measure of network structure from studies of mutualistic relationships between plants and their pollinators, we analyzed 29 ectoparasite-vertebrate host networks--including three derived from molecular bloodmeal analysis of mosquito feeding patterns--using measures of nestedness to identify non-random interactions among species. We found significant nestedness in ectoparasite-vertebrate host lists for habitats ranging from tropical rainforests to polar environments. These networks showed non-random patterns of nesting, and did not differ significantly from published estimates of nestedness from mutualistic networks. Mutualistic and antagonistic networks appear to be organized similarly, with generalized ectoparasites interacting with hosts that attract many ectoparasites and more specialized ectoparasites usually interacting with these same "generalized" hosts. This finding has implications for understanding the network dynamics of vector-born pathogens. We suggest that nestedness (rather than random ectoparasite-host associations can allow rapid transfer of pathogens throughout a network, and expand upon such concepts as the dilution effect, bridge vectors, and host switching in the context of nested ectoparasite-vertebrate host networks.

  1. Host selection by the shiny cowbird

    Science.gov (United States)

    Wiley, J.W.

    1988-01-01

    Factors important in Shiny Cowbird (Molothrus bonariensis) host selection were examined within the mangrove community in Puerto Rico. Cowbirds did not parasitize birds in proportion to their abundance. The cowbird breeding season coincided with those of its major hosts, which were 'high-quality' foster species (i.e., species that fledge .gtoreq. 55% of cowbirds hatched: Yellow Warbler, Dendroica petechia; Yellow-shouldered Blackbird, Agelaius xanthomus; Black-whiskered Vireo, Vireo altiloquus; Black-cowled Oriole, Icterus dominicensis; Peurto Rican Flycatcher, Myiarchus antillarum; Troupial, Icterus icterus), and did not extend into other periods even though nests of 'low-quality: species (i.e., species that fledge < 55% of cowbird chicks that hatched: Bronze Mannikin, Lonchura cucullata; Greater Antillean Grackle, Quiscalus niger; Gray Kingbird, Tyrannus dominicensis; Northern Mockingbird, Mimus polyglottos; Red-legged Thrush, Turdus plumbeus) were available. Shiny Cowbird food habits and egg size were similar to those of their hosts, suggesting that cowbirds choose hosts partly on the basis of this combination. Cowbirds located host nests primarily by cryptically watching activities of birds in likely habitats. Other nest locating strategies were active searching of suitable habitat and 'flushing' of hosts by the cowbird's noisy approach. Cowbirds closely monitored nest status with frequent visits that peaked on the host's first day of egg laying. Hosts using covered nests (e.g., cavities, domed nests) were as vulnerable to cowbird parasitism as those building open nests.

  2. Biofilms and host response - helpful or harmful

    DEFF Research Database (Denmark)

    Moser, Claus; Pedersen, Hannah Trøstrup; Lerche, Christian Johann

    2017-01-01

    infections can present in numerous ways, one common feature is involvement of the host response with significant impact on the course. A special characteristic is the synergy of the innate and the acquired immune responses for the induced pathology. Here, we review the impact of the host response...

  3. Social Host Ordinances and Policies. Prevention Update

    Science.gov (United States)

    Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2011

    2011-01-01

    Social host liability laws (also known as teen party ordinances, loud or unruly gathering ordinances, or response costs ordinances) target the location in which underage drinking takes place. Social host liability laws hold noncommercial individuals responsible for underage drinking events on property they own, lease, or otherwise control. They…

  4. Host tree resistance against the polyphagous

    Science.gov (United States)

    W. D. Morewood; K. Hoover; P. R. Neiner; J.R. McNeil; J. C. Sellmer

    2004-01-01

    Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiini) is an invasive wood-boring beetle with an unusually broad host range and a proven ability to increase its host range as it colonizes new areas and encounters new tree species. The beetle is native to eastern Asia and has become an invasive pest in North America and Europe,...

  5. Carp erythrodermatitis : host defense-pathogen interaction

    NARCIS (Netherlands)

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the

  6. Host genetics and dengue fever.

    Science.gov (United States)

    Xavier-Carvalho, Caroline; Cardoso, Cynthia Chester; de Souza Kehdy, Fernanda; Pacheco, Antonio Guilherme; Moraes, Milton Ozório

    2017-12-01

    Dengue is a major worldwide problem in tropical and subtropical areas; it is caused by four different viral serotypes, and it can manifest as asymptomatic, mild, or severe. Many factors interact to determine the severity of the disease, including the genetic profile of the infected patient. However, the mechanisms that lead to severe disease and eventually death have not been determined, and a great challenge is the early identification of patients who are more likely to progress to a worse health condition. Studies performed in regions with cyclic outbreaks such as Cuba, Brazil, and Colombia have demonstrated that African ancestry confers protection against severe dengue. Highlighting the host genetics as an important factor in infectious diseases, a large number of association studies between genetic polymorphisms and dengue outcomes have been published in the last two decades. The most widely used approach involves case-control studies with candidate genes, such as the HLA locus and genes for receptors, cytokines, and other immune mediators. Additionally, a Genome-Wide Association Study (GWAS) identified SNPs associated with African ethnicity that had not previously been identified in case-control studies. Despite the increasing number of publications in America, Africa, and Asia, the results are quite controversial, and a meta-analysis is needed to assess the consensus among the studies. SNPs in the MICB, TNF, CD209, FcγRIIA, TPSAB1, CLEC5A, IL10 and PLCE1 genes are associated with the risk or protection of severe dengue, and the findings have been replicated in different populations. A thorough understanding of the viral, human genetic, and immunological mechanisms of dengue and how they interact is essential for effectively preventing dengue, but also managing and treating patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. THE HOST GALAXIES OF GAMMA-RAY BURSTS. I. INTERSTELLAR MEDIUM PROPERTIES OF TEN NEARBY LONG-DURATION GAMMA-RAY BURST HOSTS

    International Nuclear Information System (INIS)

    Levesque, Emily M.; Kewley, Lisa J.; Berger, Edo; Bagley, Megan M.

    2010-01-01

    We present the first observations from a large-scale survey of nearby (z < 1) long-duration gamma-ray burst (LGRB) host galaxies, which consist of eight rest-frame optical spectra obtained at Keck and Magellan. Along with two host galaxy observations from the literature, we use optical emission-line diagnostics to determine metallicities, ionization parameters, young stellar population ages, and star formation rates. We compare the LGRB host environments to a variety of local and intermediate-redshift galaxy populations, as well as the newest grid of stellar population synthesis and photoionization models generated with the Starburst99/Mappings codes. With these comparisons, we investigate whether the GRB host galaxies are consistent with the properties of the general galaxy population, and therefore whether they may be used as reliable tracers of star formation. Despite the limitations inherent in our small sample, we find strong evidence that LGRB host galaxies generally have low-metallicity interstellar medium (ISM) environments out to z ∼ 1. The ISM properties of our GRB hosts, including metallicity and ionization parameter, are significantly different from the general galaxy population and host galaxies of nearby broad-lined Type Ic supernovae. However, these properties show better agreement with a sample of nearby metal-poor galaxies.

  8. Host-parasitoid dynamics and the success of biological control when parasitoids are prone to allee effects.

    Directory of Open Access Journals (Sweden)

    Anaïs Bompard

    Full Text Available In sexual organisms, low population density can result in mating failures and subsequently yields a low population growth rate and high chance of extinction. For species that are in tight interaction, as in host-parasitoid systems, population dynamics are primarily constrained by demographic interdependences, so that mating failures may have much more intricate consequences. Our main objective is to study the demographic consequences of parasitoid mating failures at low density and its consequences on the success of biological control. For this, we developed a deterministic host-parasitoid model with a mate-finding Allee effect, allowing to tackle interactions between the Allee effect and key determinants of host-parasitoid demography such as the distribution of parasitoid attacks and host competition. Our study shows that parasitoid mating failures at low density result in an extinction threshold and increase the domain of parasitoid deterministic extinction. When proned to mate finding difficulties, parasitoids with cyclic dynamics or low searching efficiency go extinct; parasitoids with high searching efficiency may either persist or go extinct, depending on host intraspecific competition. We show that parasitoids suitable as biocontrol agents for their ability to reduce host populations are particularly likely to suffer from mate-finding Allee effects. This study highlights novel perspectives for understanding of the dynamics observed in natural host-parasitoid systems and improving the success of parasitoid introductions.

  9. Importance of host feeding for parasitoids that attack honeydew-producing hosts

    NARCIS (Netherlands)

    Burger, J.M.S.; Komany, A.; Lenteren, van J.C.; Vet, L.E.M.

    2005-01-01

    Insect parasitoids lay their eggs in arthropods. Some parasitoid species not only use their arthropod host for oviposition but also for feeding. Host feeding provides nutrients to the adult female parasitoid. However, in many species, host feeding destroys an opportunity to oviposit. For parasitoids

  10. Compensation for risks: host community benefits in siting locally unwanted facilities

    Science.gov (United States)

    Himmelberger, Jeffery J.; Ratick, Samuel J.; White, Allen L.

    1991-09-01

    This article analyzes the recent negotiations connected with siting 24 solid-waste landfills in Wisconsin. We examine the association between the type and amount of compensation paid to host communities by facility developers and the size of facilities, certain facility characteristics, the timing of negotiated agreements, the size of the host community, and the socioeconomic status of the host area. Our findings suggest that the level of compensation after adjusting for landfill capacity is positively associated with the percentage of total facility capacity dedicated to host community use, positively associated with the percentage of people of the host area who are in poverty, and larger for public facilities that accept municipal wastes. Other explanatory variables we examined, whose association with levels of compensation proved statistically insignificant, were facility size, facility status (new vs expansion), facility use (countyonly vs multicounty), timing of negotiation, host community size, and the host area education level, population density, and per capita income. We discuss the policy implications of our principal findings and future research questions in light of the persistent opposition surrounding the siting of solid-waste and other waste-management facilities.

  11. Energy-cascade organic photovoltaic devices incorporating a host-guest architecture.

    Science.gov (United States)

    Menke, S Matthew; Holmes, Russell J

    2015-02-04

    In planar heterojunction organic photovoltaic devices (OPVs), broad spectral coverage can be realized by incorporating multiple molecular absorbers in an energy-cascade architecture. Here, this approach is combined with a host-guest donor layer architecture previously shown to optimize exciton transport for the fluorescent organic semiconductor boron subphthalocyanine chloride (SubPc) when diluted in an optically transparent host. In order to maximize the absorption efficiency, energy-cascade OPVs that utilize both photoactive host and guest donor materials are examined using the pairing of SubPc and boron subnaphthalocyanine chloride (SubNc), respectively. In a planar heterojunction architecture, excitons generated on the SubPc host rapidly energy transfer to the SubNc guest, where they may migrate toward the dissociating, donor-acceptor interface. Overall, the incorporation of a photoactive host leads to a 13% enhancement in the short-circuit current density and a 20% enhancement in the power conversion efficiency relative to an optimized host-guest OPV combining SubNc with a nonabsorbing host. This work underscores the potential for further design refinements in planar heterojunction OPVs and demonstrates progress toward the effective separation of functionality between constituent OPV materials.

  12. Intrinsic-density functionals

    International Nuclear Information System (INIS)

    Engel, J.

    2007-01-01

    The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to functionals of the localized intrinsic density of a self-bound system such as a nucleus. After defining the intrinsic-density functional, we modify the usual Kohn-Sham procedure slightly to evaluate the mean-field approximation to the functional, and carefully describe the construction of the leading corrections for a system of fermions in one dimension with a spin-degeneracy equal to the number of particles N. Despite the fact that the corrections are complicated and nonlocal, we are able to construct a local Skyrme-like intrinsic-density functional that, while different from the exact functional, shares with it a minimum value equal to the exact ground-state energy at the exact ground-state intrinsic density, to next-to-leading order in 1/N. We briefly discuss implications for real Skyrme functionals

  13. Density functional theory

    International Nuclear Information System (INIS)

    Das, M.P.

    1984-07-01

    The state of the art of the density functional formalism (DFT) is reviewed. The theory is quantum statistical in nature; its simplest version is the well-known Thomas-Fermi theory. The DFT is a powerful formalism in which one can treat the effect of interactions in inhomogeneous systems. After some introductory material, the DFT is outlined from the two basic theorems, and various generalizations of the theorems appropriate to several physical situations are pointed out. Next, various approximations to the density functionals are presented and some practical schemes, discussed; the approximations include an electron gas of almost constant density and an electron gas of slowly varying density. Then applications of DFT in various diverse areas of physics (atomic systems, plasmas, liquids, nuclear matter) are mentioned, and its strengths and weaknesses are pointed out. In conclusion, more recent developments of DFT are indicated

  14. Low Density Supersonic Decelerators

    Data.gov (United States)

    National Aeronautics and Space Administration — The Low-Density Supersonic Decelerator project will demonstrate the use of inflatable structures and advanced parachutes that operate at supersonic speeds to more...

  15. density functional theory approach

    Indian Academy of Sciences (India)

    YOGESH ERANDE

    2017-07-27

    Jul 27, 2017 ... a key role in all optical switching devices, since their optical properties can be .... optimized in the gas phase using Density Functional Theory. (DFT).39 The ...... The Mediation of Electrostatic Effects by Sol- vents J. Am. Chem.

  16. Bone mineral density test

    Science.gov (United States)

    BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; Osteoporosis - BMD ... need to undress. This scan is the best test to predict your risk of fractures, especially of ...

  17. Density scaling for multiplets

    International Nuclear Information System (INIS)

    Nagy, A

    2011-01-01

    Generalized Kohn-Sham equations are presented for lowest-lying multiplets. The way of treating non-integer particle numbers is coupled with an earlier method of the author. The fundamental quantity of the theory is the subspace density. The Kohn-Sham equations are similar to the conventional Kohn-Sham equations. The difference is that the subspace density is used instead of the density and the Kohn-Sham potential is different for different subspaces. The exchange-correlation functional is studied using density scaling. It is shown that there exists a value of the scaling factor ζ for which the correlation energy disappears. Generalized OPM and Krieger-Li-Iafrate (KLI) methods incorporating correlation are presented. The ζKLI method, being as simple as the original KLI method, is proposed for multiplets.

  18. Codivergence of mycoviruses with their hosts.

    Directory of Open Access Journals (Sweden)

    Markus Göker

    Full Text Available BACKGROUND: The associations between pathogens and their hosts are complex and can result from any combination of evolutionary events such as codivergence, switching, and duplication of the pathogen. Mycoviruses are RNA viruses which infect fungi and for which natural vectors are so far unknown. Thus, lateral transfer might be improbable and codivergence their dominant mode of evolution. Accordingly, mycoviruses are a suitable target for statistical tests of virus-host codivergence, but inference of mycovirus phylogenies might be difficult because of low sequence similarity even within families. METHODOLOGY: We analyzed here the evolutionary dynamics of all mycovirus families by comparing virus and host phylogenies. Additionally, we assessed the sensitivity of the co-phylogenetic tests to the settings for inferring virus trees from their genome sequences and approximate, taxonomy-based host trees. CONCLUSIONS: While sequence alignment filtering modes affected branch support, the overall results of the co-phylogenetic tests were significantly influenced only by the number of viruses sampled per family. The trees of the two largest families, Partitiviridae and Totiviridae, were significantly more similar to those of their hosts than expected by chance, and most individual host-virus links had a significant positive impact on the global fit, indicating that codivergence is the dominant mode of virus diversification. However, in this regard mycoviruses did not differ from closely related viruses sampled from non-fungus hosts. The remaining virus families were either dominated by other evolutionary modes or lacked an apparent overall pattern. As this negative result might be caused by insufficient taxon sampling, the most parsimonious hypothesis still is that host-parasite evolution is basically the same in all mycovirus families. This is the first study of mycovirus-host codivergence, and the results shed light not only on how mycovirus biology

  19. Effect of Intermediate Hosts on Emerging Zoonoses.

    Science.gov (United States)

    Cui, Jing-An; Chen, Fangyuan; Fan, Shengjie

    2017-08-01

    Most emerging zoonotic pathogens originate from animals. They can directly infect humans through natural reservoirs or indirectly through intermediate hosts. As a bridge, an intermediate host plays different roles in the transmission of zoonotic pathogens. In this study, we present three types of pathogen transmission to evaluate the effect of intermediate hosts on emerging zoonotic diseases in human epidemics. These types are identified as follows: TYPE 1, pathogen transmission without an intermediate host for comparison; TYPE 2, pathogen transmission with an intermediate host as an amplifier; and TYPE 3, pathogen transmission with an intermediate host as a vessel for genetic variation. In addition, we established three mathematical models to elucidate the mechanisms underlying zoonotic disease transmission according to these three types. Stability analysis indicated that the existence of intermediate hosts increased the difficulty of controlling zoonotic diseases because of more difficult conditions to satisfy for the disease to die out. The human epidemic would die out under the following conditions: TYPE 1: [Formula: see text] and [Formula: see text]; TYPE 2: [Formula: see text], [Formula: see text], and [Formula: see text]; and TYPE 3: [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] Simulation with similar parameters demonstrated that intermediate hosts could change the peak time and number of infected humans during a human epidemic; intermediate hosts also exerted different effects on controlling the prevalence of a human epidemic with natural reservoirs in different periods, which is important in addressing problems in public health. Monitoring and controlling the number of natural reservoirs and intermediate hosts at the right time would successfully manage and prevent the prevalence of emerging zoonoses in humans.

  20. Fission level densities

    International Nuclear Information System (INIS)

    Maslov, V.M.

    1998-01-01

    Fission level densities (or fissioning nucleus level densities at fission saddle deformations) are required for statistical model calculations of actinide fission cross sections. Back-shifted Fermi-Gas Model, Constant Temperature Model and Generalized Superfluid Model (GSM) are widely used for the description of level densities at stable deformations. These models provide approximately identical level density description at excitations close to the neutron binding energy. It is at low excitation energies that they are discrepant, while this energy region is crucial for fission cross section calculations. A drawback of back-shifted Fermi gas model and traditional constant temperature model approaches is that it is difficult to include in a consistent way pair correlations, collective effects and shell effects. Pair, shell and collective properties of nucleus do not reduce just to the renormalization of level density parameter a, but influence the energy dependence of level densities. These effects turn out to be important because they seem to depend upon deformation of either equilibrium or saddle-point. These effects are easily introduced within GSM approach. Fission barriers are another key ingredients involved in the fission cross section calculations. Fission level density and barrier parameters are strongly interdependent. This is the reason for including fission barrier parameters along with the fission level densities in the Starter File. The recommended file is maslov.dat - fission barrier parameters. Recent version of actinide fission barrier data obtained in Obninsk (obninsk.dat) should only be considered as a guide for selection of initial parameters. These data are included in the Starter File, together with the fission barrier parameters recommended by CNDC (beijing.dat), for completeness. (author)

  1. Density-wave oscillations

    International Nuclear Information System (INIS)

    Belblidia, L.A.; Bratianu, C.

    1979-01-01

    Boiling flow in a steam generator, a water-cooled reactor, and other multiphase processes can be subject to instabilities. It appears that the most predominant instabilities are the so-called density-wave oscillations. They can cause difficulties for three main reasons; they may induce burnout; they may cause mechanical vibrations of components; and they create system control problems. A comprehensive review is presented of experimental and theoretical studies concerning density-wave oscillations. (author)

  2. Density of liquid Ytterbium

    International Nuclear Information System (INIS)

    Stankus, S.V.; Basin, A.S.

    1983-01-01

    Results are presented for measurements of the density of metallic ytterbium in the liquid state and at the liquid-solid phase transition. Based on the numerical data obtained, the coefficient of thermal expansion βZ of the liquid and the density discontinuity on melting deltarho/sub m/ are calculated. The magnitudes of βZ and deltarho/sub m/ for the heavy lanthanides are compared

  3. Deep-Sea Hydrothermal Vent Viruses Compensate for Microbial Metabolism in Virus-Host Interactions.

    Science.gov (United States)

    He, Tianliang; Li, Hongyun; Zhang, Xiaobo

    2017-07-11

    Viruses are believed to be responsible for the mortality of host organisms. However, some recent investigations reveal that viruses may be essential for host survival. To date, it remains unclear whether viruses are beneficial or harmful to their hosts. To reveal the roles of viruses in the virus-host interactions, viromes and microbiomes of sediment samples from three deep-sea hydrothermal vents were explored in this study. To exclude the influence of exogenous DNAs on viromes, the virus particles were purified with nuclease (DNase I and RNase A) treatments and cesium chloride density gradient centrifugation. The metagenomic analysis of viromes without exogenous DNA contamination and microbiomes of vent samples indicated that viruses had compensation effects on the metabolisms of their host microorganisms. Viral genes not only participated in most of the microbial metabolic pathways but also formed branched pathways in microbial metabolisms, including pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; nitrogen metabolism and assimilation pathways of the two-component system; selenocompound metabolism; aminoacyl-tRNA biosynthesis; and amino sugar and nucleotide sugar metabolism. As is well known, deep-sea hydrothermal vent ecosystems exist in relatively isolated environments which are barely influenced by other ecosystems. The metabolic compensation of hosts mediated by viruses might represent a very important aspect of virus-host interactions. IMPORTANCE Viruses are the most abundant biological entities in the oceans and have very important roles in regulating microbial community structure and biogeochemical cycles. The relationship between virus and host microbes is broadly thought to be that of predator and prey. Viruses can lyse host cells to control microbial population sizes and affect community structures of hosts by killing specific microbes. However, viruses also influence their hosts through manipulation of bacterial metabolism. We found

  4. Negative Ion Density Fronts

    International Nuclear Information System (INIS)

    Igor Kaganovich

    2000-01-01

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

  5. Trypanosome infection establishment in the tsetse fly gut is influenced by microbiome-regulated host immune barriers.

    Directory of Open Access Journals (Sweden)

    Brian L Weiss

    Full Text Available Tsetse flies (Glossina spp. vector pathogenic African trypanosomes, which cause sleeping sickness in humans and nagana in domesticated animals. Additionally, tsetse harbors 3 maternally transmitted endosymbiotic bacteria that modulate their host's physiology. Tsetse is highly resistant to infection with trypanosomes, and this phenotype depends on multiple physiological factors at the time of challenge. These factors include host age, density of maternally-derived trypanolytic effector molecules present in the gut, and symbiont status during development. In this study, we investigated the molecular mechanisms that result in tsetse's resistance to trypanosomes. We found that following parasite challenge, young susceptible tsetse present a highly attenuated immune response. In contrast, mature refractory flies express higher levels of genes associated with humoral (attacin and pgrp-lb and epithelial (inducible nitric oxide synthase and dual oxidase immunity. Additionally, we discovered that tsetse must harbor its endogenous microbiome during intrauterine larval development in order to present a parasite refractory phenotype during adulthood. Interestingly, mature aposymbiotic flies (Gmm(Apo present a strong immune response earlier in the infection process than do WT flies that harbor symbiotic bacteria throughout their entire lifecycle. However, this early response fails to confer significant resistance to trypanosomes. Gmm(Apo adults present a structurally compromised peritrophic matrix (PM, which lines the fly midgut and serves as a physical barrier that separates luminal contents from immune responsive epithelial cells. We propose that the early immune response we observe in Gmm(Apo flies following parasite challenge results from the premature exposure of gut epithelia to parasite-derived immunogens in the absence of a robust PM. Thus, tsetse's PM appears to regulate the timing of host immune induction following parasite challenge. Our results

  6. Experimental investigation of alternative transmission functions: Quantitative evidence for the importance of nonlinear transmission dynamics in host-parasite systems.

    Science.gov (United States)

    Orlofske, Sarah A; Flaxman, Samuel M; Joseph, Maxwell B; Fenton, Andy; Melbourne, Brett A; Johnson, Pieter T J

    2018-05-01

    Understanding pathogen transmission is crucial for predicting and managing disease. Nonetheless, experimental comparisons of alternative functional forms of transmission remain rare, and those experiments that are conducted are often not designed to test the full range of possible forms. To differentiate among 10 candidate transmission functions, we used a novel experimental design in which we independently varied four factors-duration of exposure, numbers of parasites, numbers of hosts and parasite density-in laboratory infection experiments. We used interactions between amphibian hosts and trematode parasites as a model system and all candidate models incorporated parasite depletion. An additional manipulation involving anaesthesia addressed the effects of host behaviour on transmission form. Across all experiments, nonlinear transmission forms involving either a power law or a negative binomial function were the best-fitting models and consistently outperformed the linear density-dependent and density-independent functions. By testing previously published data for two other host-macroparasite systems, we also found support for the same nonlinear transmission forms. Although manipulations of parasite density are common in transmission studies, the comprehensive set of variables tested in our experiments revealed that variation in density alone was least likely to differentiate among competing transmission functions. Across host-pathogen systems, nonlinear functions may often more accurately represent transmission dynamics and thus provide more realistic predictions for infection. © 2017 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

  7. Host response to biomaterials the impact of host response on biomaterial selection

    CERN Document Server

    Badylak, Stephen F

    2015-01-01

    Host Response to Biomaterials: The Impact of Host Response on Biomaterial Selection explains the various categories of biomaterials and their significance for clinical applications, focusing on the host response to each biomaterial. It is one of the first books to connect immunology and biomaterials with regard to host response. The text also explores the role of the immune system in host response, and covers the regulatory environment for biomaterials, along with the benefits of synthetic versus natural biomaterials, and the transition from simple to complex biomaterial solutions. Fiel

  8. Mechanisms of host seeking by parasitic nematodes.

    Science.gov (United States)

    Gang, Spencer S; Hallem, Elissa A

    2016-07-01

    The phylum Nematoda comprises a diverse group of roundworms that includes parasites of vertebrates, invertebrates, and plants. Human-parasitic nematodes infect more than one billion people worldwide and cause some of the most common neglected tropical diseases, particularly in low-resource countries [1]. Parasitic nematodes of livestock and crops result in billions of dollars in losses each year [1]. Many nematode infections are treatable with low-cost anthelmintic drugs, but repeated infections are common in endemic areas and drug resistance is a growing concern with increasing therapeutic and agricultural administration [1]. Many parasitic nematodes have an environmental infective larval stage that engages in host seeking, a process whereby the infective larvae use sensory cues to search for hosts. Host seeking is a complex behavior that involves multiple sensory modalities, including olfaction, gustation, thermosensation, and humidity sensation. As the initial step of the parasite-host interaction, host seeking could be a powerful target for preventative intervention. However, host-seeking behavior remains poorly understood. Here we review what is currently known about the host-seeking behaviors of different parasitic nematodes, including insect-parasitic nematodes, mammalian-parasitic nematodes, and plant-parasitic nematodes. We also discuss the neural bases of these behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Bartonella entry mechanisms into mammalian host cells.

    Science.gov (United States)

    Eicher, Simone C; Dehio, Christoph

    2012-08-01

    The Gram-negative genus Bartonella comprises arthropod-borne pathogens that typically infect mammals in a host-specific manner. Bartonella bacilliformis and Bartonella quintana are human-specific pathogens, while several zoonotic bartonellae specific for diverse animal hosts infect humans as an incidental host. Clinical manifestations of Bartonella infections range from mild symptoms to life-threatening disease. Following transmission by blood-sucking arthropods or traumatic contact with infected animals, bartonellae display sequential tropisms towards endothelial and possibly other nucleated cells and erythrocytes, the latter in a host-specific manner. Attachment to the extracellular matrix (ECM) and to nucleated cells is mediated by surface-exposed bacterial adhesins, in particular trimeric autotransporter adhesins (TAAs). The subsequent engulfment of the pathogen into a vacuolar structure follows a unique series of events whereby the pathogen avoids the endolysosomal compartments. For Bartonella henselae and assumingly most other species, the infection process is aided at different steps by Bartonella effector proteins (Beps). They are injected into host cells through the type IV secretion system (T4SS) VirB/D4 and subvert host cellular functions to favour pathogen uptake. Bacterial binding to erythrocytes is mediated by Trw, another T4SS, in a strictly host-specific manner, followed by pathogen-forced uptake involving the IalB invasin and subsequent replication and persistence within a membrane-bound intra-erythrocytic compartment. © 2012 Blackwell Publishing Ltd.

  10. Associate host in single-layer co-host polymer electrophosphorescent devices

    International Nuclear Information System (INIS)

    Wang Yuanmin; Teng Feng; Feng Bin; Wang Yongsheng; Xu Xurong

    2006-01-01

    The definition and role of 'host' in polymer LED materials are studied in the present work. 'Primary host' and 'associate host' have been proposed and the rules of how to select an associate host are reported. Based on our experiments and the analysis of the energy scheme of the devices, we suggest that the values of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) are critical determinant in selecting a suitable associate host. On one hand, the associate host should be a hole-blocking material. This can confine the excitons in the active layer. On the other hand, the associate host should have a suitable LUMO that is convenient for electrons to transport

  11. Studies on avian malaria in vectors and hosts of encephalitis in Kern County, California. I. Infections in avian hosts

    Science.gov (United States)

    Herman, C.M.; Reeves, W.C.; McClure, H.E.; French, E.M.; Hammon, W.M.

    1954-01-01

    An epizoological study of Plasmodium infections in wild birds of Kern County, California, in the years 1946 through 1951 greatly extended knowledge of the occurrence of these parasites and their behavior in nature. Examination of 10,459 blood smears from 8,674 birds representing 73 species resulted in the observation of Plasmodium spp. in 1,094 smears representing 888 individual birds of 27 species. Seven species of Plasmodium were found: relictum, elongatum, hexamerium, nucleophilum, polare, rouxi and vaughani. Plasmodium relictum was by far the most frequently observed species, occurring in at least 79 per cent of the infected birds. Twelve new host species are recorded for this parasite. Sufficient morphological variation was observed to indicate that two strains of this species probably exist in nature. Numerous new host records were made of plasmodia with elongate gametocytes. The finding of parasites believed to be P. rouxi in two new host species represents the first record of the occurrence of this Plasmodium outside of Algeria. Multiple smears were obtained from a number of individual birds over varying time periods. Evidence of prolonged parasitemia was unusual, but some individuals had parasitemia on consecutive months and even for three successive years. In most individuals, parasitemias were of short duration. The inoculation of blood from wild birds into canaries led to the demonstration of many infections not observed on blood smear examination of donors. Use of these two complementary techniques led to more complete host records and a truer picture of the prevalence of infection. Three age classes of birds were studied--nestling, immature (less than 1 year of age) and adult. Parasites were observed in all three groups but infections in the younger individuals were most susceptible to interpretation. As to time of onset, numerous records were obtained of infection in nestling birds. Prevalence rates in immature birds after a single season's exposure

  12. Host conservatism or host specialization? Patterns of fungal diversification are influenced by host specificity in Ophiognomonia (Gnomoniaceae, Diaporthales)

    Science.gov (United States)

    Species of Ophiognomonia (Gnomoniaceae) are perithecial fungi that occur as endophytes, pathogens, and latent saprobes on leaf and stem tissue of plants in the Betulaceae, Fagaceae, Juglandaceae, Lauraceae, Malvaceae, Platanaceae, Rosaceae, Salicaceae, and Sapindaceae. In this study host plant patte...

  13. Infection Unit Density as an Index of Infection Potential of Arbuscular Mycorrhizal Fungi.

    Science.gov (United States)

    Ohtomo, Ryo; Kobae, Yoshihiro; Morimoto, Sho; Oka, Norikuni

    2018-03-29

    The effective use of arbuscular mycorrhizal (AM) fungal function to promote host plant phosphate uptake in agricultural practice requires the accurate quantitative evaluation of AM fungal infection potential in field soil or AM fungal inoculation material. The number of infection units (IUs), intraradical fungal structures derived from single root entries formed after a short cultivation period, may reflect the number of propagules in soil when pot soil is completely permeated by the host root. However, the original IU method, in which all AM propagules in a pot are counted, requires the fine tuning of plant growing conditions and is considered to be laborious. The objective of the present study was to test whether IU density, not the total count of IU, but the number of IUs per unit root length, reflects the density of AM fungal propagules in soil. IU density assessed after 12 d of host plant cultivation and 3,3'-diaminobenzidine (DAB) staining showed a stronger linear correlation with propagule density than the mean infection percentage (MIP). In addition, IU density was affected less by the host plant species than MIP. We suggest that IU density provides a more rapid and reliable quantitation of the propagule density of AM fungi than MIP or the original IU method. Thus, IU density may be a more robust index of AM fungal infection potential for research and practical applications.

  14. Chemical similarity between historical and novel host plants promotes range and host expansion of the mountain pine beetle in a naïve host ecosystem.

    Science.gov (United States)

    Erbilgin, Nadir; Ma, Cary; Whitehouse, Caroline; Shan, Bin; Najar, Ahmed; Evenden, Maya

    2014-02-01

    Host plant secondary chemistry can have cascading impacts on host and range expansion of herbivorous insect populations. We investigated the role of host secondary compounds on pheromone production by the mountain pine beetle (Dendroctonus ponderosae) (MPB) and beetle attraction in response to a historical (lodgepole pine, Pinus contorta var. latifolia) and a novel (jack pine, Pinus banksiana) hosts, as pheromones regulate the host colonization process. Beetles emit the same pheromones from both hosts, but more trans-verbenol, the primary aggregation pheromone, was emitted by female beetles on the novel host. The phloem of the novel host contains more α-pinene, a secondary compound that is the precursor for trans-verbenol production in beetle, than the historical host. Beetle-induced emission of 3-carene, another secondary compound found in both hosts, was also higher from the novel host. Field tests showed that the addition of 3-carene to the pheromone mixture mimicking the aggregation pheromones produced from the two host species increased beetle capture. We conclude that chemical similarity between historical and novel hosts has facilitated host expansion of MPB in jack pine forests through the exploitation of common host secondary compounds for pheromone production and aggregation on the hosts. Furthermore, broods emerging from the novel host were larger in terms of body size. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  15. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  16. Density regulation in Northeast Atlantic fish populations: Density dependence is stronger in recruitment than in somatic growth.

    Science.gov (United States)

    Zimmermann, Fabian; Ricard, Daniel; Heino, Mikko

    2018-05-01

    Population regulation is a central concept in ecology, yet in many cases its presence and the underlying mechanisms are difficult to demonstrate. The current paradigm maintains that marine fish populations are predominantly regulated by density-dependent recruitment. While it is known that density-dependent somatic growth can be present too, its general importance remains unknown and most practical applications neglect it. This study aimed to close this gap by for the first time quantifying and comparing density dependence in growth and recruitment over a large set of fish populations. We fitted density-dependent models to time-series data on population size, recruitment and age-specific weight from commercially exploited fish populations in the Northeast Atlantic Ocean and the Baltic Sea. Data were standardized to enable a direct comparison within and among populations, and estimated parameters were used to quantify the impact of density regulation on population biomass. Statistically significant density dependence in recruitment was detected in a large proportion of populations (70%), whereas for density dependence in somatic growth the prevalence of density dependence depended heavily on the method (26% and 69%). Despite age-dependent variability, the density dependence in recruitment was consistently stronger among age groups and between alternative approaches that use weight-at-age or weight increments to assess growth. Estimates of density-dependent reduction in biomass underlined these results: 97% of populations with statistically significant parameters for growth and recruitment showed a larger impact of density-dependent recruitment on population biomass. The results reaffirm the importance of density-dependent recruitment in marine fishes, yet they also show that density dependence in somatic growth is not uncommon. Furthermore, the results are important from an applied perspective because density dependence in somatic growth affects productivity and

  17. High density dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, G.L.

    1996-01-01

    A fuel development campaign that results in an aluminum plate-type fuel of unlimited LEU burnup capability with an uranium loading of 9 grams per cm 3 of meat should be considered an unqualified success. The current worldwide approved and accepted highest loading is 4.8 g cm -3 with U 3 Si 2 as fuel. High-density uranium compounds offer no real density advantage over U 3 Si 2 and have less desirable fabrication and performance characteristics as well. Of the higher-density compounds, U 3 Si has approximately a 30% higher uranium density but the density of the U 6 X compounds would yield the factor 1.5 needed to achieve 9 g cm -3 uranium loading. Unfortunately, irradiation tests proved these peritectic compounds have poor swelling behavior. It is for this reason that the authors are turning to uranium alloys. The reason pure uranium was not seriously considered as a dispersion fuel is mainly due to its high rate of growth and swelling at low temperatures. This problem was solved at least for relatively low burnup application in non-dispersion fuel elements with small additions of Si, Fe, and Al. This so called adjusted uranium has nearly the same density as pure α-uranium and it seems prudent to reconsider this alloy as a dispersant. Further modifications of uranium metal to achieve higher burnup swelling stability involve stabilization of the cubic γ phase at low temperatures where normally α phase exists. Several low neutron capture cross section elements such as Zr, Nb, Ti and Mo accomplish this in various degrees. The challenge is to produce a suitable form of fuel powder and develop a plate fabrication procedure, as well as obtain high burnup capability through irradiation testing

  18. Sex Determination from Fingerprint Ridge Density | Gungadin ...

    African Journals Online (AJOL)

    This study was conducted with an aim to establish a relationship between sex and fingerprint ridge density. The fingerprints were taken from 500 subjects (250 males and 250 females) in the age group of 18-60 years. After taking fingerprints, the ridges were counted in the upper portion of the radial border of each print for all ...

  19. Phalangeal bone mineral density predicts incident fractures

    DEFF Research Database (Denmark)

    Friis-Holmberg, Teresa; Brixen, Kim; Rubin, Katrine Hass

    2012-01-01

    This prospective study investigates the use of phalangeal bone mineral density (BMD) in predicting fractures in a cohort (15,542) who underwent a BMD scan. In both women and men, a decrease in BMD was associated with an increased risk of fracture when adjusted for age and prevalent fractures...

  20. Thyroid Stimulating Hormone and Bone Mineral Density

    DEFF Research Database (Denmark)

    van Vliet, Nicolien A; Noordam, Raymond; van Klinken, Jan B

    2018-01-01

    With population aging, prevalence of low bone mineral density (BMD) and associated fracture risk are increased. To determine whether low circulating thyroid stimulating hormone (TSH) levels within the normal range are causally related to BMD, we conducted a two-sample Mendelian randomization (MR...

  1. Gap and density theorems

    CERN Document Server

    Levinson, N

    1940-01-01

    A typical gap theorem of the type discussed in the book deals with a set of exponential functions { \\{e^{{{i\\lambda}_n} x}\\} } on an interval of the real line and explores the conditions under which this set generates the entire L_2 space on this interval. A typical gap theorem deals with functions f on the real line such that many Fourier coefficients of f vanish. The main goal of this book is to investigate relations between density and gap theorems and to study various cases where these theorems hold. The author also shows that density- and gap-type theorems are related to various propertie

  2. Nuclear level density

    International Nuclear Information System (INIS)

    Cardoso Junior, J.L.

    1982-10-01

    Experimental data show that the number of nuclear states increases rapidly with increasing excitation energy. The properties of highly excited nuclei are important for many nuclear reactions, mainly those that go via processes of the compound nucleus type. In this case, it is sufficient to know the statistical properties of the nuclear levels. First of them is the function of nuclear levels density. Several theoretical models which describe the level density are presented. The statistical mechanics and a quantum mechanics formalisms as well as semi-empirical results are analysed and discussed. (Author) [pt

  3. Polarizable Density Embedding

    DEFF Research Database (Denmark)

    Olsen, Jógvan Magnus Haugaard; Steinmann, Casper; Ruud, Kenneth

    2015-01-01

    We present a new QM/QM/MM-based model for calculating molecular properties and excited states of solute-solvent systems. We denote this new approach the polarizable density embedding (PDE) model and it represents an extension of our previously developed polarizable embedding (PE) strategy. The PDE...... model is a focused computational approach in which a core region of the system studied is represented by a quantum-chemical method, whereas the environment is divided into two other regions: an inner and an outer region. Molecules belonging to the inner region are described by their exact densities...

  4. Holographic magnetisation density waves

    Energy Technology Data Exchange (ETDEWEB)

    Donos, Aristomenis [Centre for Particle Theory and Department of Mathematical Sciences, Durham University,Stockton Road, Durham, DH1 3LE (United Kingdom); Pantelidou, Christiana [Departament de Fisica Quantica i Astrofisica & Institut de Ciencies del Cosmos (ICC),Universitat de Barcelona,Marti i Franques 1, 08028 Barcelona (Spain)

    2016-10-10

    We numerically construct asymptotically AdS black brane solutions of D=4 Einstein theory coupled to a scalar and two U(1) gauge fields. The solutions are holographically dual to d=3 CFTs in a constant external magnetic field along one of the U(1)’s. Below a critical temperature the system’s magnetisation density becomes inhomogeneous, leading to spontaneous formation of current density waves. We find that the transition can be of second order and that the solutions which minimise the free energy locally in the parameter space of solutions have averaged stressed tensor of a perfect fluid.

  5. Towards host-directed therapies for tuberculosis.

    Science.gov (United States)

    Zumla, Alimuddin; Maeurer, Markus; Chakaya, Jeremiah; Hoelscher, Michael; Ntoumi, Francine; Rustomjee, Roxana; Vilaplana, Cristina; Yeboah-Manu, Dorothy; Rasolof, Voahangy; Munderi, Paula; Singh, Nalini; Aklillu, Eleni; Padayatchi, Nesri; Macete, Eusebio; Kapata, Nathan; Mulenga, Modest; Kibiki, Gibson; Mfinanga, Sayoki; Nyirenda, Thomas; Maboko, Leonard; Garcia-Basteiro, Alberto; Rakotosamimanana, Niaina; Bates, Matthew; Mwaba, Peter; Reither, Klaus; Gagneux, Sebastien; Edwards, Sarah; Mfinanga, Elirehema; Abdulla, Salim; Cardona, Pere-Joan; Russell, James B W; Gant, Vanya; Noursadeghi, Mahdad; Elkington, Paul; Bonnet, Maryline; Menendez, Clara; Dieye, Tandakha N; Diarra, Bassirou; Maiga, Almoustapha; Aseffa, Abraham; Parida, Shreemanta; Wejse, Christian; Petersen, Eskild; Kaleebu, Pontiano; Oliver, Matt; Craig, Gill; Corrah, Tumena; Tientcheu, Leopold; Antonio, Martin; Rao, Martin; McHugh, Timothy D; Sheikh, Aziz; Ippolito, Giuseppe; Ramjee, Gita; Kaufmann, Stefan H E; Churchyard, Gavin; Steyn, Andrie; Grobusch, Martin; Sanne, Ian; Martinson, Neil; Madansein, Rajhmun; Wilkinson, Robert J; Mayosi, Bongani; Schito, Marco; Wallis, Robert S

    2015-08-01

    The treatment of tuberculosis is based on combinations of drugs that directly target Mycobacterium tuberculosis. A new global initiative is now focusing on a complementary approach of developing adjunct host-directed therapies.

  6. Hologenomics: Systems-Level Host Biology.

    Science.gov (United States)

    Theis, Kevin R

    2018-01-01

    The hologenome concept of evolution is a hypothesis explaining host evolution in the context of the host microbiomes. As a hypothesis, it needs to be evaluated, especially with respect to the extent of fidelity of transgenerational coassociation of host and microbial lineages and the relative fitness consequences of repeated associations within natural holobiont populations. Behavioral ecologists are in a prime position to test these predictions because they typically focus on animal phenotypes that are quantifiable, conduct studies over multiple generations within natural animal populations, and collect metadata on genetic relatedness and relative reproductive success within these populations. Regardless of the conclusion on the hologenome concept as an evolutionary hypothesis, a hologenomic perspective has applied value as a systems-level framework for host biology, including in medicine. Specifically, it emphasizes investigating the multivarious and dynamic interactions between patient genomes and the genomes of their diverse microbiota when attempting to elucidate etiologies of complex, noninfectious diseases.

  7. Host Plants of Xylosandrus mutilatus in Mississippi

    International Nuclear Information System (INIS)

    Stone, W.D.; Nebeker, T.E.; Gerard, P.D.

    2007-01-01

    Host range of Xylosandrus mutilatus (Blandford) in North America is reported here for the first time. Descriptive data such as number of attacks per host, size of stems at point of attacks, and height of attacks above ground are presented. Hosts observed in Mississippi were Acer rubrum L., Acer saccharum Marsh., Acer palmatum Thunb., Ostrya virginiana (Mill.) K. Koch., Cornus florida L., Fagus grandifolia Ehrh., Liquidamber styraciflua L., Carya spp., Liriodendron tulipifera L., Melia azedarach L., Pinus taeda L., Prunus serotina Ehrh., Prunus americana Marsh., Ulmus alata Michaux, and Vitus rotundifolia Michaux. Liquidamber styraciflua had significantly more successful attacks, significantly higher probability of attacks, and significantly higher number of adult beetles per host tree than did Carya spp., A. rubrum, and L. tulipifera. This information is relevant in determining the impact this exotic beetle may have in nurseries, urban areas, and other forestry systems where this beetle becomes established. (author) [es

  8. CERN to host conference on information society

    CERN Multimedia

    CERN will host a conference on the Role of Science in the Information Society (RSIS) in December. This conference will focus on ensuring that the information society benefits people to the greatest extent possible, especially in developing regions.

  9. Host-bacterial interplay in periodontal disease

    Directory of Open Access Journals (Sweden)

    Rudrakshi Chickanna

    2015-01-01

    Full Text Available A literature search was performed using MEDLINE (PubMed and other electronic basis from 1991 to 2014. Search included books and journals based on the systematic and critical reviews, in vitro and in vivo clinical studies on molecular basis of host microbial interactions. Clearly, an understanding of the host susceptibility factor in addition to microbial factors by elucidating the molecular basis offers opportunity for therapeutic manipulation of advancing periodontal destruction. One of the hallmarks of pathogenesis is the ability of pathogenic organisms to invade surrounding tissues and to evade the host defence. This paper focuses the general overview of molecular mechanisms involved in the microbiota and host response to bacterial inimical behavior in periodontics.

  10. Bacteria modulate the CD8+ T cell epitope repertoire of host cytosol-exposed proteins to manipulate the host immune response.

    Directory of Open Access Journals (Sweden)

    Yaakov Maman

    2011-10-01

    Full Text Available The main adaptive immune response to bacteria is mediated by B cells and CD4+ T-cells. However, some bacterial proteins reach the cytosol of host cells and are exposed to the host CD8+ T-cells response. Both gram-negative and gram-positive bacteria can translocate proteins to the cytosol through type III and IV secretion and ESX-1 systems, respectively. The translocated proteins are often essential for the bacterium survival. Once injected, these proteins can be degraded and presented on MHC-I molecules to CD8+ T-cells. The CD8+ T-cells, in turn, can induce cell death and destroy the bacteria's habitat. In viruses, escape mutations arise to avoid this detection. The accumulation of escape mutations in bacteria has never been systematically studied. We show for the first time that such mutations are systematically present in most bacteria tested. We combine multiple bioinformatic algorithms to compute CD8+ T-cell epitope libraries of bacteria with secretion systems that translocate proteins to the host cytosol. In all bacteria tested, proteins not translocated to the cytosol show no escape mutations in their CD8+ T-cell epitopes. However, proteins translocated to the cytosol show clear escape mutations and have low epitope densities for most tested HLA alleles. The low epitope densities suggest that bacteria, like viruses, are evolutionarily selected to ensure their survival in the presence of CD8+ T-cells. In contrast with most other translocated proteins examined, Pseudomonas aeruginosa's ExoU, which ultimately induces host cell death, was found to have high epitope density. This finding suggests a novel mechanism for the manipulation of CD8+ T-cells by pathogens. The ExoU effector may have evolved to maintain high epitope density enabling it to efficiently induce CD8+ T-cell mediated cell death. These results were tested using multiple epitope prediction algorithms, and were found to be consistent for most proteins tested.

  11. Directional Selection from Host Plants Is a Major Force Driving Host Specificity in Magnaporthe Species.

    Science.gov (United States)

    Zhong, Zhenhui; Norvienyeku, Justice; Chen, Meilian; Bao, Jiandong; Lin, Lianyu; Chen, Liqiong; Lin, Yahong; Wu, Xiaoxian; Cai, Zena; Zhang, Qi; Lin, Xiaoye; Hong, Yonghe; Huang, Jun; Xu, Linghong; Zhang, Honghong; Chen, Long; Tang, Wei; Zheng, Huakun; Chen, Xiaofeng; Wang, Yanli; Lian, Bi; Zhang, Liangsheng; Tang, Haibao; Lu, Guodong; Ebbole, Daniel J; Wang, Baohua; Wang, Zonghua

    2016-05-06

    One major threat to global food security that requires immediate attention, is the increasing incidence of host shift and host expansion in growing number of pathogenic fungi and emergence of new pathogens. The threat is more alarming because, yield quality and quantity improvement efforts are encouraging the cultivation of uniform plants with low genetic diversity that are increasingly susceptible to emerging pathogens. However, the influence of host genome differentiation on pathogen genome differentiation and its contribution to emergence and adaptability is still obscure. Here, we compared genome sequence of 6 isolates of Magnaporthe species obtained from three different host plants. We demonstrated the evolutionary relationship between Magnaporthe species and the influence of host differentiation on pathogens. Phylogenetic analysis showed that evolution of pathogen directly corresponds with host divergence, suggesting that host-pathogen interaction has led to co-evolution. Furthermore, we identified an asymmetric selection pressure on Magnaporthe species. Oryza sativa-infecting isolates showed higher directional selection from host and subsequently tends to lower the genetic diversity in its genome. We concluded that, frequent gene loss or gain, new transposon acquisition and sequence divergence are host adaptability mechanisms for Magnaporthe species, and this coevolution processes is greatly driven by directional selection from host plants.

  12. Poxvirus Host Range Genes and Virus–Host Spectrum: A Critical Review

    Science.gov (United States)

    Oliveira, Graziele Pereira; Rodrigues, Rodrigo Araújo Lima; Lima, Maurício Teixeira; Drumond, Betânia Paiva; Abrahão, Jônatas Santos

    2017-01-01

    The Poxviridae family is comprised of double-stranded DNA viruses belonging to nucleocytoplasmic large DNA viruses (NCLDV). Among the NCLDV, poxviruses exhibit the widest known host range, which is likely observed because this viral family has been more heavily investigated. However, relative to each member of the Poxviridae family, the spectrum of the host is variable, where certain viruses can infect a large range of hosts, while others are restricted to only one host species. It has been suggested that the variability in host spectrum among poxviruses is linked with the presence or absence of some host range genes. Would it be possible to extrapolate the restriction of viral replication in a specific cell lineage to an animal, a far more complex organism? In this study, we compare and discuss the relationship between the host range of poxvirus species and the abundance/diversity of host range genes. We analyzed the sequences of 38 previously identified and putative homologs of poxvirus host range genes, and updated these data with deposited sequences of new poxvirus genomes. Overall, the term host range genes might not be the most appropriate for these genes, since no correlation between them and the viruses’ host spectrum was observed, and a change in nomenclature should be considered. Finally, we analyzed the evolutionary history of these genes, and reaffirmed the occurrence of horizontal gene transfer (HGT) for certain elements, as previously suggested. Considering the data presented in this study, it is not possible to associate the diversity of host range factors with the amount of hosts of known poxviruses, and this traditional nomenclature creates misunderstandings. PMID:29112165

  13. Poxvirus Host Range Genes and Virus-Host Spectrum: A Critical Review.

    Science.gov (United States)

    Oliveira, Graziele Pereira; Rodrigues, Rodrigo Araújo Lima; Lima, Maurício Teixeira; Drumond, Betânia Paiva; Abrahão, Jônatas Santos

    2017-11-07

    The Poxviridae family is comprised of double-stranded DNA viruses belonging to nucleocytoplasmic large DNA viruses (NCLDV). Among the NCLDV, poxviruses exhibit the widest known host range, which is likely observed because this viral family has been more heavily investigated. However, relative to each member of the Poxviridae family, the spectrum of the host is variable, where certain viruses can infect a large range of hosts, while others are restricted to only one host species. It has been suggested that the variability in host spectrum among poxviruses is linked with the presence or absence of some host range genes. Would it be possible to extrapolate the restriction of viral replication in a specific cell lineage to an animal, a far more complex organism? In this study, we compare and discuss the relationship between the host range of poxvirus species and the abundance/diversity of host range genes. We analyzed the sequences of 38 previously identified and putative homologs of poxvirus host range genes, and updated these data with deposited sequences of new poxvirus genomes. Overall, the term host range genes might not be the most appropriate for these genes, since no correlation between them and the viruses' host spectrum was observed, and a change in nomenclature should be considered. Finally, we analyzed the evolutionary history of these genes, and reaffirmed the occurrence of horizontal gene transfer (HGT) for certain elements, as previously suggested. Considering the data presented in this study, it is not possible to associate the diversity of host range factors with the amount of hosts of known poxviruses, and this traditional nomenclature creates misunderstandings.

  14. Host reproductive phenology drives seasonal patterns of host use in mosquitoes.

    Directory of Open Access Journals (Sweden)

    Nathan D Burkett-Cadena

    2011-03-01

    Full Text Available Seasonal shifts in host use by mosquitoes from birds to mammals drive the timing and intensity of annual epidemics of mosquito-borne viruses, such as West Nile virus, in North America. The biological mechanism underlying these shifts has been a matter of debate, with hypotheses falling into two camps: (1 the shift is driven by changes in host abundance, or (2 the shift is driven by seasonal changes in the foraging behavior of mosquitoes. Here we explored the idea that seasonal changes in host use by mosquitoes are driven by temporal patterns of host reproduction. We investigated the relationship between seasonal patterns of host use by mosquitoes and host reproductive phenology by examining a seven-year dataset of blood meal identifications from a site in Tuskegee National Forest, Alabama USA and data on reproduction from the most commonly utilized endothermic (white-tailed deer, great blue heron, yellow-crowned night heron and ectothermic (frogs hosts. Our analysis revealed that feeding on each host peaked during periods of reproductive activity. Specifically, mosquitoes utilized herons in the spring and early summer, during periods of peak nest occupancy, whereas deer were fed upon most during the late summer and fall, the period corresponding to the peak in births for deer. For frogs, however, feeding on early- and late-season breeders paralleled peaks in male vocalization. We demonstrate for the first time that seasonal patterns of host use by mosquitoes track the reproductive phenology of the hosts. Peaks in relative mosquito feeding on each host during reproductive phases are likely the result of increased tolerance and decreased vigilance to attacking mosquitoes by nestlings and brooding adults (avian hosts, quiescent young (avian and mammalian hosts, and mate-seeking males (frogs.

  15. Data hosting infrastructure for primary biodiversity data

    Science.gov (United States)

    2011-01-01

    Background Today, an unprecedented volume of primary biodiversity data are being generated worldwide, yet significant amounts of these data have been and will continue to be lost after the conclusion of the projects tasked with collecting them. To get the most value out of these data it is imperative to seek a solution whereby these data are rescued, archived and made available to the biodiversity community. To this end, the biodiversity informatics community requires investment in processes and infrastructure to mitigate data loss and provide solutions for long-term hosting and sharing of biodiversity data. Discussion We review the current state of biodiversity data hosting and investigate the technological and sociological barriers to proper data management. We further explore the rescuing and re-hosting of legacy data, the state of existing toolsets and propose a future direction for the development of new discovery tools. We also explore the role of data standards and licensing in the context of data hosting and preservation. We provide five recommendations for the biodiversity community that will foster better data preservation and access: (1) encourage the community's use of data standards, (2) promote the public domain licensing of data, (3) establish a community of those involved in data hosting and archival, (4) establish hosting centers for biodiversity data, and (5) develop tools for data discovery. Conclusion The community's adoption of standards and development of tools to enable data discovery is essential to sustainable data preservation. Furthermore, the increased adoption of open content licensing, the establishment of data hosting infrastructure and the creation of a data hosting and archiving community are all necessary steps towards the community ensuring that data archival policies become standardized. PMID:22373257

  16. Cdc42 promotes host defenses against fatal infection

    DEFF Research Database (Denmark)

    Lee, Keunwook; Boyd, Kelli L; Parekh, Diptiben V

    2013-01-01

    attempted to specifically delete it in these cells by crossing the Cdc42(fl/fl) mouse with a FSP-1 cre mouse, which is thought to mediate recombination exclusively in fibroblasts. Surprisingly, the FSP-1cre;Cdc42(fl/fl) mice died at 3 weeks of age due to overwhelming suppurative upper airway infections...... showed that in addition to fibroblasts, the FSP-1 cre deleted Cdc42 very efficiently in all leukocytes. Thus, by using this non-specific cre mouse we inadvertently demonstrated the importance of Cdc42 in host protection from lethal infections and suggest a critical role for this small GTPase in innate...

  17. Host identity is a dominant driver of mycorrhizal fungal community composition during ecosystem development.

    Science.gov (United States)

    Martínez-García, Laura B; Richardson, Sarah J; Tylianakis, Jason M; Peltzer, Duane A; Dickie, Ian A

    2015-03-01

    Little is known about the response of arbuscular mycorrhizal fungal communities to ecosystem development. We use a long-term soil chronosequence that includes ecosystem progression and retrogression to quantify the importance of host plant identity as a factor driving fungal community composition during ecosystem development. We identified arbuscular mycorrhizal fungi and plant species from 50 individual roots from each of 10 sites spanning 5-120 000 yr of ecosystem age using terminal restriction fragment length polymorphism (T-RFLP), Sanger sequencing and pyrosequencing. Arbuscular mycorrhizal fungal communities were highly structured by ecosystem age. There was strong niche differentiation, with different groups of operational taxonomic units (OTUs) being characteristic of early succession, ecosystem progression and ecosystem retrogression. Fungal alpha diversity decreased with ecosystem age, whereas beta diversity was high at early stages and lower in subsequent stages. A total of 39% of the variance in fungal communities was explained by host plant and site age, 29% of which was attributed to host and the interaction between host and site (24% and 5%, respectively). The strong response of arbuscular mycorrhizal fungi to ecosystem development appears to be largely driven by plant host identity, supporting the concept that plant and fungal communities are tightly coupled rather than independently responding to habitat. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  18. Development of Meteorus pulchricornis and regulation of its noctuid host, Pseudaletia separata.

    Science.gov (United States)

    Suzuki, M; Tanaka, T

    2007-10-01

    The solitary endoparasitoid Meteorus pulchricornis can parasitize many lepidopteran host species successfully. In the case of parasitization of Pseudaletia separata, developmental duration of M. pulchricornis was 8-9 days from egg to larval emergence and 6 days from prepupa to adult emergence. Successful parasitism by M. pulchricornis decreased with host age. Following parasitization of day-0 4th host instar, the parasitoid embryo, whilst still enclosed in serosal cell membrane, hatched out of the egg chorion 2 days after oviposition. Subsequently, the 1st instar parasitoid emerged from the surrounding serosal cell membrane. Serosal cells dissociated and developed as teratocytes 3.5 days after oviposition. One embryo of M. pulchricornis gave rise to approximately 1200 teratocytes, a number that remained constant until 6 days after parasitization, but decreased drastically to 200 at 7 days post-oviposition. The teratocytes of M. pulchricornis were round- or oval-shaped and grew from 65 microm at 4 days to 200 microm in the long axis at 6 days post-parasitization. At 4 days post-parasitization, many cells or cell clusters with lipid particles were observed in the hemocoels of parasitized hosts. In addition, paraffin sections of parasitized hosts revealed that many teratocytes were attached to the host's fat body and contributed to disrupting the fat body tissue. Further, examination of the total hemocyte count (THC) during parasitization revealed that THC was maintained at low levels. Surprisingly, a temporal decrease followed by restoration of THC was observed in hosts injected with virus-like particles of M. pulchricornis (MpVLPs) plus venom, which contrasts with the constant THC suppression seen in parasitized hosts. This indicates that MpVLP function is temporal and is involved in regulation of the host during early parasitism. Therefore, teratocytes, a host regulation factor in late parasitism, could be involved in keeping THC at a low level.

  19. Towards a better understanding of Lactobacillus rhamnosus GG - host interactions

    Science.gov (United States)

    2014-01-01

    Lactobacillus rhamnosus GG (LGG) is one of the most widely used probiotic strains. Various health effects are well documented including the prevention and treatment of gastro-intestinal infections and diarrhea, and stimulation of immune responses that promote vaccination or even prevent certain allergic symptoms. However, not all intervention studies could show a clinical benefit and even for the same con