WorldWideScience

Sample records for human disturbance electronic

  1. [Ecotourism disturbances to non-human primates].

    Science.gov (United States)

    Fan, Peng-Lai; Xiang, Zuo-Fu

    2013-02-01

    In tandem with economic growth and rising living conditions, ecotourism has increasingly gained popularity among the Chinese public. Non-human primates, as charismatic animals and the closest relatives of human beings, have shown a strong affinity in attracting the general public and raising money, and for that reason a variety of monkey parks, valleys, and islands are becoming increasingly popular in China. Though successful in raising a substantial sum of money for the managing agency of a nature reserve, there may be negative impacts on monkey groups used in ecotourism. Here, to establish effective guards for non-human primates involved in ecotourism, we present a review on tourism disturbance and summarize the negative impacts on behavioral patterns, reproduction, and health condition of animals.

  2. Plant hybridization: the role of human disturbance and biological invasion

    Science.gov (United States)

    Qinfeng Guo

    2014-01-01

    Aim Anderson & Stebbins (1954, Evolution, 8, 378–388) posited that human activities promote species hybridizations by creating opportunities for hybridization and new habitats for hybrids to persist through disturbances (i.e. the ‘disturbance hypothesis’). While the first part of this hypothesis appears to be well supported, the second part has...

  3. Impacts of geo-physical factors and human disturbance on ...

    African Journals Online (AJOL)

    We examined vegetation-disturbance-environment relationships in the Xiaomengyang Section of Xishuangbanna Nature Reserve (XNR) using multivariate analysis to understand the impacts of geo-physical factors and human disturbance on vegetation along the highway corridor. We found that native forests were the best ...

  4. Inter-specific variation in avian responses to human disturbance

    Science.gov (United States)

    Daniel T. Blumstein; Esteban Fernandez-Juricic; Patrick A. Zollner; Susan C. Garity

    2005-01-01

    1. Increasing urbanization and recreational activities around and within biodiversity hotspots require an understanding of how to reduce the impacts of human disturbance on more than a single species; however, we lack a general framework to study multiple species. One approach is to expand on knowledge about the theory of anti-predator behaviour to understand and...

  5. Sandhill crane roost selection, human disturbance, and forage resources

    Science.gov (United States)

    Pearse, Aaron T.; Krapu, Gary; Brandt, David

    2017-01-01

    Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring-staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focused on physical channel characteristics related to perceived security as motivating roost distribution. We used 6,310 roost sites selected by 313 sandhill cranes over 5 spring migration seasons (2003–2007) to quantify resource selection functions of roost sites on the central Platte River using a discrete choice analysis. Sandhill cranes generally showed stronger selection for wider channels with shorter bank vegetation situated farther from potential human disturbance features such as roads, bridges, and dwellings. Furthermore, selection for roost sites with preferable physical characteristics (wide channels with short bank vegetation) was more resilient to nearby disturbance features than more narrow channels with taller bank vegetation. The amount of cornfields surrounding sandhill crane roost sites positively influenced relative probability of use but only for more narrow channels resource features that sandhill cranes selected at river channels along the Platte River, and after incorporating spatial variation due to human disturbance, our understanding of roost site selection was more robust, providing insights on how disturbance may interact with physical habitat features. Managers can use information on roost-site selection when developing plans to increase probability of crane use at existing roost sites and to identify new areas for potential use if existing sites become limited.

  6. Sandhill crane roost selection, human disturbance, and forage resources

    Science.gov (United States)

    Pearse, Aaron T.; Krapu, Gary; Brandt, David

    2017-01-01

    Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring-staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focused on physical channel characteristics related to perceived security as motivating roost distribution. We used 6,310 roost sites selected by 313 sandhill cranes over 5 spring migration seasons (2003–2007) to quantify resource selection functions of roost sites on the central Platte River using a discrete choice analysis. Sandhill cranes generally showed stronger selection for wider channels with shorter bank vegetation situated farther from potential human disturbance features such as roads, bridges, and dwellings. Furthermore, selection for roost sites with preferable physical characteristics (wide channels with short bank vegetation) was more resilient to nearby disturbance features than more narrow channels with taller bank vegetation. The amount of cornfields surrounding sandhill crane roost sites positively influenced relative probability of use but only for more narrow channels < 100 m and those with shorter bank vegetation. We confirmed key resource features that sandhill cranes selected at river channels along the Platte River, and after incorporating spatial variation due to human disturbance, our understanding of roost site selection was more robust, providing insights on how disturbance may interact with physical habitat features. Managers can use information on roost-site selection when developing plans to increase probability of crane use at existing roost sites and to identify new areas for potential use if

  7. Human disturbances of denning polar bears in Alaska

    International Nuclear Information System (INIS)

    Amstrup, S.C.

    1993-01-01

    Polar bears (Ursus maritimus) give birth in dens of snow and ice. The altricial neonates cannot leave the den for >2 months post-partum and are potentially vulnerable to disturbances near dens. The coastal plain (1002) area of Alaska's Arctic National Wildlife Refuge (ANWR) lies in a region of known polar bear denning and also may contain >9 billion barrels of recoverable oil. Polar bears in dens could be affected in many ways by hydrocarbon development. The distribution of dens on ANWR was documented between 1981 and 1992 and responses of bears in dens to various anthropogenic disturbances were observed. Of 44 dens located by radiotelemetry on the mainland coast of Alaska and Canada, 20 (45%) were on ANWR and 15 (34%) were within the 1002 area. Thus, development of ANWR will increase the potential that denning polar bears are disturbed by human activities. However, perturbations resulting from capture, marking, and radiotracking maternal bears did not affect litter sizes or stature of cubs produced. Likewise, 10 of 12 denned polar bears tolerated exposure to exceptional levels of activity. This tolerance and the fact that investment in the denning effort increases through the winter indicated that spatial and temporal restrictions on developments could prevent the potential for many disruptions of denned bears from being realized. 16 refs., 1 fig., 2 tabs

  8. Human reproductive system disturbances and pesticide exposure in Brazil

    Directory of Open Access Journals (Sweden)

    Koifman Sergio

    2002-01-01

    Full Text Available The observation of reproductive disturbances in humans and in the wildlife has been reported in the last decade in different countries. Exposure to different chemicals possibly acting in the endocrine system or endocrine disruptors, including pesticides, has been a hypothesis raised to explain the observed changes. This paper aimed to present results of an epidemiological ecologic study carried out to explore population data on pesticides exposure in selected Brazilian states in the eighties and human reproductive outcomes in the nineties. Pearson correlation coefficients were ascertained between available data pesticides sales in eleven states in Brazil in 1985 and selected further reproductive outcomes or their surrogates. Moderate to high correlations were observed to infertility, testis, breast, prostate and ovarian cancer mortality. Despite the restrains of ecologic studies to establish cause-effect relationships, the observed results are in agreement with evidence supporting a possible association between pesticides exposure and the analyzed reproductive outcomes.

  9. Adolescents' electronic media use at night, sleep disturbance, and depressive symptoms in the smartphone age.

    Science.gov (United States)

    Lemola, Sakari; Perkinson-Gloor, Nadine; Brand, Serge; Dewald-Kaufmann, Julia F; Grob, Alexander

    2015-02-01

    Adolescence is a time of increasing vulnerability for poor mental health, including depression. Sleep disturbance is an important risk factor for the development of depression during adolescence. Excessive electronic media use at night is a risk factor for both adolescents' sleep disturbance and depression. To better understand the interplay between sleep, depressive symptoms, and electronic media use at night, this study examined changes in adolescents' electronic media use at night and sleep associated with smartphone ownership. Also examined was whether sleep disturbance mediated the relationship between electronic media use at night and depressive symptoms. 362 adolescents (12-17 year olds, M = 14.8, SD = 1.3; 44.8% female) were included and completed questionnaires assessing sleep disturbance (short sleep duration and sleep difficulties) and depressive symptoms. Further, participants reported on their electronic media use in bed before sleep such as frequency of watching TV or movies, playing video games, talking or text messaging on the mobile phone, and spending time online. Smartphone ownership was related to more electronic media use in bed before sleep, particularly calling/sending messages and spending time online compared to adolescents with a conventional mobile phone. Smartphone ownership was also related to later bedtimes while it was unrelated to sleep disturbance and symptoms of depression. Sleep disturbance partially mediated the relationship between electronic media use in bed before sleep and symptoms of depression. Electronic media use was negatively related with sleep duration and positively with sleep difficulties, which in turn were related to depressive symptoms. Sleep difficulties were the more important mediator than sleep duration. The results of this study suggest that adolescents might benefit from education regarding sleep hygiene and the risks of electronic media use at night.

  10. Experimental evidence for effects of human disturbance on foraging and parental care in oystercatchers

    NARCIS (Netherlands)

    Verhulst, S; Oosterbeek, K; Ens, B.J.

    2001-01-01

    We carried out two experiments to quantify effects of human disturbance on foraging and parental care in European oystercatchers (Haematopus ostralegus). In experiment 1, pairs incubating a clutch were disturbed on their feeding territory on the mudflat. Disturbance significantly reduced the

  11. Disturbances of electrodynamic activity affect abortion in human

    International Nuclear Information System (INIS)

    Jandová, A; Cifra, M; Pokorný, J; Nedbalová, M; Dohnalová, A; Kobilková, J; Cocek, A

    2011-01-01

    Biochemical research of biological systems is highly developed, and it has disclosed a spectrum of chemical reactions, genetic processes, and the pathological development of various diseases. The fundamental hypothesis of physical processes in biological systems, in particular of coherent electrically polar vibrations and electromagnetic activity, was formulated by H. Fröhlich; he assumed connection of cancer process with degradation of coherent electromagnetic activity. But the questions of cellular structures capable of the coherent electrical polar oscillation, mechanisms of energy supply, and the specific role of the endogenous electromagnetic fields in transport, organisation, interactions, and information transfer remained open. The nature of physical disturbances caused by some diseases (including the recurrent abortion in humans and the cancer) was unknown. We have studied the reasons of recurrent abortions in humans by means of the cell mediated immunity (using immunologic active RNA prepared from blood of inbred laboratory mice strain C3H/H2K, infected with the lactate dehydrogenase elevating virus-LD V) and the cytogenetic examination from karyotype pictures. The recurrent abortion group contained women with dg. spontaneous abortion (n = 24) and the control group was composed of 30 healthy pregnant women. Our hypothesis was related to quality of endometrium in relation to nidation of the blastocyst. The energetic insufficiency (ATP) inhibits normal development of fetus and placenta. We hope that these ideas might have impact on further research, which could provide background for effective interdisciplinary cooperation of malignant and non-malignant diseases.

  12. Disturbances of electrodynamic activity affect abortion in human

    Science.gov (United States)

    Jandová, A.; Nedbalová, M.; Kobilková, J.; Čoček, A.; Dohnalová, A.; Cifra, M.; Pokorný, J.

    2011-12-01

    Biochemical research of biological systems is highly developed, and it has disclosed a spectrum of chemical reactions, genetic processes, and the pathological development of various diseases. The fundamental hypothesis of physical processes in biological systems, in particular of coherent electrically polar vibrations and electromagnetic activity, was formulated by H. Fröhlich he assumed connection of cancer process with degradation of coherent electromagnetic activity. But the questions of cellular structures capable of the coherent electrical polar oscillation, mechanisms of energy supply, and the specific role of the endogenous electromagnetic fields in transport, organisation, interactions, and information transfer remained open. The nature of physical disturbances caused by some diseases (including the recurrent abortion in humans and the cancer) was unknown. We have studied the reasons of recurrent abortions in humans by means of the cell mediated immunity (using immunologic active RNA prepared from blood of inbred laboratory mice strain C3H/H2K, infected with the lactate dehydrogenase elevating virus-LD V) and the cytogenetic examination from karyotype pictures. The recurrent abortion group contained women with dg. spontaneous abortion (n = 24) and the control group was composed of 30 healthy pregnant women. Our hypothesis was related to quality of endometrium in relation to nidation of the blastocyst. The energetic insufficiency (ATP) inhibits normal development of fetus and placenta. We hope that these ideas might have impact on further research, which could provide background for effective interdisciplinary cooperation of malignant and non-malignant diseases.

  13. Empirical model for the electron density peak height disturbance in response to solar wind conditions

    Science.gov (United States)

    Blanch, E.; Altadill, D.

    2009-04-01

    Geomagnetic storms disturb the quiet behaviour of the ionosphere, its electron density and the electron density peak height, hmF2. Many works have been done to predict the variations of the electron density but few efforts have been dedicated to predict the variations the hmF2 under disturbed helio-geomagnetic conditions. We present the results of the analyses of the F2 layer peak height disturbances occurred during intense geomagnetic storms for one solar cycle. The results systematically show a significant peak height increase about 2 hours after the beginning of the main phase of the geomagnetic storm, independently of both the local time position of the station at the onset of the storm and the intensity of the storm. An additional uplift is observed in the post sunset sector. The duration of the uplift and the height increase are dependent of the intensity of the geomagnetic storm, the season and the local time position of the station at the onset of the storm. An empirical model has been developed to predict the electron density peak height disturbances in response to solar wind conditions and local time which can be used for nowcasting and forecasting the hmF2 disturbances for the middle latitude ionosphere. This being an important output for EURIPOS project operational purposes.

  14. Electronic cigarettes: human health effects

    OpenAIRE

    Callahan-Lyon, Priscilla

    2014-01-01

    Objective With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Methods Literature searches were conducted through September 2013 using multiple electronic databases. Results Forty-four articles are included in this analysis. E-cigarette ae...

  15. The history of human disturbance in forest ecosystems of southern Indiana

    Science.gov (United States)

    Michael A. Jenkins

    2013-01-01

    The forests of southern Indiana have been shaped and defined by anthropogenic disturbance. Native Americans influenced composition and structure through land clearing and burning, but the scale and rate of human disturbance intensified with European settlement. Sustained settlement led to the loss of forest land to agriculture and livestock grazing. Forests were also...

  16. Relativistic Electrons Produced by Foreshock Disturbances Observed Upstream of Earth's Bow Shock

    Science.gov (United States)

    Wilson, L. B., III; Sibeck, D. G.; Turner, D. L.; Osmane, A.; Caprioli, D.; Angelopoulos, V.

    2016-01-01

    Charged particles can be reflected and accelerated by strong (i.e., high Mach number) astrophysical collisionless shock waves, streaming away to form a foreshock region in communication with the shock. Foreshocks are primarily populated by suprathermal ions that can generate foreshock disturbances-largescale (i.e., tens to thousands of thermal ion Larmor radii), transient (approximately 5-10 per day) structures. They have recently been found to accelerate ions to energies of several keV. Although electrons in Saturn's high Mach number (M > 40) bow shock can be accelerated to relativistic energies (nearly 1000 keV), it has hitherto been thought impossible to accelerate electrons beyond a few tens of keV at Earth's low Mach number (1 =M foreshock disturbances to energies up to at least approximately 300 keV. Although such energetic electrons have been previously observed, their presence has been attributed to escaping magnetospheric particles or solar events. These relativistic electrons are not associated with any solar or magnetospheric activity. Further, due to their relatively small Larmor radii (compared to magnetic gradient scale lengths) and large thermal speeds (compared to shock speeds), no known shock acceleration mechanism can energize thermal electrons up to relativistic energies. The discovery of relativistic electrons associated with foreshock structures commonly generated in astrophysical shocks could provide a new paradigm for electron injections and acceleration in collisionless plasmas.

  17. Reactions of chamois to human disturbance in Berchtesgaden National Park

    Directory of Open Access Journals (Sweden)

    Bögel, R.

    2002-12-01

    Full Text Available The objective of this study was to test whether the source and frequence of disturbance result in different behavioural responses of Chamois and if practical management guidelines can be drawn from these findings. The results clearly indicate that type and frequency of the disturbance have a strong influence on the behavioural response and that the disturbance tolerance varies with season, time of the day, sex and group size. Disturbances from flying resulted in a much stronger response than disturbances from the ground, and the response increased with velocity and/or noise level of the disturbance source. In areas with frequent disturbances the behavioural response was reduced when compared with remote areas, indicating habituation effects. While distance at first reaction and flight distance varied with disturbance intensity, the length of the flight path was not influenced by the disturbance type and frequency. Habitat use was also affected by disturbances: postdisturbance habitat types were mainly rocks and forests indicating a shift in habitat selection towards inaccessible habitat types or habitat types with good cover.

    [fr]
    Chez les chamois, nous avons étudié l’influence des différentes perturbations de diverses fréquences sur le comportement et nous nous sommes demandés si les résultats obtenus pouvaient orienter la gestion des populations. En effet, aussi bien le type que la fréquence de la perturbation ont influencé de manière significative le comportement. De plus, la tolérance aux perturbations varie avec la saison, l'heure du jour, le sexe et la taille du groupe. Les perturbations produites par des engins aériens ont provoqué une réponse beaucoup plus forte que celles provenant du terrain; la réponse étant augmentée avec la vitesse ou le degré du bruit de la source de perturbation. Là où les perturbations étaient fréquentes, la réponse se voyait réduite par rapport a des territoires

  18. Electronic Textbook in Human Physiology.

    Science.gov (United States)

    Broering, Naomi C.; Lilienfield, Lawrence S.

    1994-01-01

    Describes the development of an electronic textbook in human physiology at the Georgetown University Medical Center Library that was designed to enhance learning and visualization through a prototype knowledge base of core instructional materials stored in digital format on Macintosh computers. The use of computers in the medical curriculum is…

  19. Ground-nesting marine birds and potential for human disturbance in Glacier Bay National Park

    Science.gov (United States)

    Arimitsu, Mayumi L.; Romano, Marc D.; Piatt, John F.; Piatt, John F.; Gende, S.M.

    2004-01-01

    Glacier Bay National Park and Preserve contains a diverse assemblage of marine birds that use the area for nesting, foraging and molting. The abundance and diversity of marine bird species in Glacier Bay is unmatched in the region, due in part to the geomorphic and successional characteristics that result in a wide array of habitat types (Robards and others, 2003). The opportunity for proactive management of these species is unique in Glacier Bay National Park because much of the suitable marine bird nesting habitat occurs in areas designated as wilderness. Ground-nesting marine birds are vulnerable to human disturbance wherever visitors can access nest sites during the breeding season. Human disturbance of nest sites can be significant because intense parental care is required for egg and hatchling survival, and repeated disturbance can result in reduced productivity (Leseberg and others, 2000). Temporary nest desertion by breeding birds in disturbed areas can lead to increased predation on eggs and hatchlings by conspecifics or other predators (Bolduc and Guillemette, 2003). Human disturbance of ground-nesting birds may also affect incubation time and adult foraging success, which in turn can alter breeding success (Verhulst and others, 2001). Furthermore, human activity can potentially cause colony failure when disturbance prevents the initiation of nesting (Hatch, 2002). There is management concern about the susceptibility of breeding birds to disturbance from human activities, but little historical data has been collected on the distribution of ground-nesting marine birds in Glacier Bay. This report summarizes results obtained during two years of a three-year study to determine the distribution of ground-nesting marine birds in Glacier Bay, and the potential for human disturbance of those nesting birds.

  20. Experimental evidence of human recreational disturbance effects on bird-territory establishment.

    Science.gov (United States)

    Bötsch, Yves; Tablado, Zulima; Jenni, Lukas

    2017-07-12

    The worldwide increase in human outdoor activities raises concerns for wildlife. Human disturbances, even at low levels, are likely to impact species during sensitive periods of the annual cycle. However, experimental studies during the putative sensitive period of territory establishment of birds which not only investigate low disturbance levels, but which also exclude the effect of habitat modification (e.g. walking trails) are lacking. Here, we experimentally disturbed birds in forest plots by walking through twice a day during territory establishment. Later we compared the breeding bird community of experimentally disturbed plots with that of undisturbed control plots. We discovered that the number of territories (-15.0%) and species richness (-15.2%) in disturbed plots were substantially reduced compared with control plots. Species most affected included those sensitive to human presence (assessed by flight-initiation distances), open-cup nesters and above-ground foragers. Long-distance migrants, however, were unaffected due to their arrival after experimental disturbance took place. These findings highlight how territory establishment is a sensitive period for birds, when even low levels of human recreation may be perceived as threatening, and alter settlement decisions. This can have important implications for the conservation of species, which might go unnoticed when focusing only on already established birds. © 2017 The Author(s).

  1. Identifying community thresholds for lotic benthic diatoms in response to human disturbance.

    Science.gov (United States)

    Tang, Tao; Tang, Ting; Tan, Lu; Gu, Yuan; Jiang, Wanxiang; Cai, Qinghua

    2017-06-23

    Although human disturbance indirectly influences lotic assemblages through modifying physical and chemical conditions, identifying thresholds of human disturbance would provide direct evidence for preventing anthropogenic degradation of biological conditions. In the present study, we used data obtained from tributaries of the Three Gorges Reservoir in China to detect effects of human disturbance on streams and to identify disturbance thresholds for benthic diatoms. Diatom species composition was significantly affected by three in-stream stressors including TP, TN and pH. Diatoms were also influenced by watershed % farmland and natural environmental variables. Considering three in-stream stressors, TP was positively influenced by % farmland and % impervious surface area (ISA). In contrast, TN and pH were principally affected by natural environmental variables. Among measured natural environmental variables, average annual air temperature, average annual precipitation, and topsoil % CaCO 3 , % gravel, and total exchangeable bases had significant effects on study streams. When effects of natural variables were accounted for, substantial compositional changes in diatoms occurred when farmland or ISA land use exceeded 25% or 0.3%, respectively. Our study demonstrated the rationale for identifying thresholds of human disturbance for lotic assemblages and addressed the importance of accounting for effects of natural factors for accurate disturbance thresholds.

  2. A meta-analysis of human disturbance impacts on Antarctic wildlife.

    Science.gov (United States)

    Coetzee, Bernard W T; Chown, Steven L

    2016-08-01

    Evidence-based assessments are increasingly recognized as the best-practice approach to determine appropriate conservation interventions, but such assessments of the impact of human disturbance on wildlife are rare. Human disturbance comprises anthropogenic activities that are typically non-lethal, but may cause short- and/or longer-term stress and fitness responses in wildlife. Expanding human activity in the Antarctic region is of particular concern because it increases the scope and potential for increased human disturbance to wildlife in a region that is often thought of as relatively untouched by anthropogenic influences. Here, we use a meta-analytical approach to synthesise research on human disturbance to wildlife over the last three decades in the Antarctic and sub-Antarctic region. We combine data from 62 studies across 21 species on the behavioural, physiological and population responses of wildlife to pedestrian, vehicle and research disturbances. The overall effect size indicated a small, albeit statistically significant negative effect of disturbance (-0.39; 95% CI: -0.60 to -0.18). Negative effects were found for both physiological and population responses, but no evidence was found for a significant impact on wildlife behavioural responses. Negative effects were found across pedestrian, vehicle and research disturbances. Significant and high among-study heterogeneity was found in both disturbance and response sub-groups. Among species, it remains unclear to what extent different forms of disturbance translate into negative population responses. Most current guidelines to limit wildlife disturbance impacts in Antarctica recommend that approaches be tailored to animal behavioural cues, but our work demonstrates that behavioural changes do not necessarily reflect more cryptic, and more deleterious impacts, such as changes in physiology. In consequence, we recommend that pedestrian approach guidelines in the Antarctic region be revisited. Due to the high

  3. Human disturbance alters endocrine and immune responses in the Galapagos marine iguana (Amblyrhynchus cristatus)

    Science.gov (United States)

    French, Susannah S; DeNardo, Dale F.; Greives, Timothy J.; Strand, Christine R.; Demas, Gregory E.

    2010-01-01

    Anthropogenic disturbance is a relevant and widespread facilitator of environmental change and there is clear evidence that it impacts natural populations. While population-level responses to major anthropogenic changes have been well studied, individual physiological responses to mild disturbance can be equally critical to the long-term survival of a species, yet they remain largely unexamined. The current study investigated the impact of seemingly low-level anthropogenic disturbance (ecotourism) on stress responsiveness and specific fitness-related immune measures in different breeding stages of the marine iguana (Amblyrhynchus cristatus). Specifically, we found stress-induced elevations in plasma corticosterone among tourist-exposed populations relative to undisturbed populations. We also found changes in multiple immunological responses associated with stress-related effects of human disturbance, including bacterial killing ability, cutaneous wound healing, and hemolytic complement activity, and the responses varied according to reproductive state. By identifying health-related consequences of human disturbance, this study provides critical insight into the conservation of a well-known species that has a very distinct ecology. The study also broadens the foundation of knowledge needed to understand the global significance of various levels of human disturbance. PMID:20708010

  4. Human disturbance alters endocrine and immune responses in the Galapagos marine iguana (Amblyrhynchus cristatus).

    Science.gov (United States)

    French, Susannah S; DeNardo, Dale F; Greives, Timothy J; Strand, Christine R; Demas, Gregory E

    2010-11-01

    Anthropogenic disturbance is a relevant and widespread facilitator of environmental change and there is clear evidence that it impacts natural populations. While population-level responses to major anthropogenic changes have been well studied, individual physiological responses to mild disturbance can be equally critical to the long-term survival of a species, yet they remain largely unexamined. The current study investigated the impact of seemingly low-level anthropogenic disturbance (ecotourism) on stress responsiveness and specific fitness-related immune measures in different breeding stages of the marine iguana (Amblyrhynchus cristatus). Specifically, we found stress-induced elevations in plasma corticosterone among tourist-exposed populations relative to undisturbed populations. We also found changes in multiple immunological responses associated with stress-related effects of human disturbance, including bacterial killing ability, cutaneous wound healing, and hemolytic complement activity, and the responses varied according to reproductive state. By identifying health-related consequences of human disturbance, this study provides critical insight into the conservation of a well-known species that has a very distinct ecology. The study also broadens the foundation of knowledge needed to understand the global significance of various levels of human disturbance. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Capturing community context of human response to forest disturbance by insects: a multi-method assessment

    Science.gov (United States)

    Hua Qin; Courtney G. Flint

    2010-01-01

    The socioeconomic and environmental features of local places (community context) influence the relationship between humans and their physical environment. In times of environmental disturbance, this community context is expected to influence human perceptual and behavioral responses. Residents from nine Colorado communities experiencing a large outbreak of mountain...

  6. Using Landsat time series for characterizing forest disturbance dynamics in the coupled human and natural systems of Central Europe.

    Science.gov (United States)

    Senf, Cornelius; Pflugmacher, Dirk; Hostert, Patrick; Seidl, Rupert

    2017-08-01

    Remote sensing is a key information source for improving the spatiotemporal understanding of forest ecosystem dynamics. Yet, the mapping and attribution of forest change remains challenging, particularly in areas where a number of interacting disturbance agents simultaneously affect forest development. The forest ecosystems of Central Europe are coupled human and natural systems, with natural and human disturbances affecting forests both individually and in combination. To better understand the complex forest disturbance dynamics in such systems, we utilize 32-year Landsat time series to map forest disturbances in five sites across Austria, the Czech Republic, Germany, Poland, and Slovakia. All sites consisted of a National Park and the surrounding forests, reflecting three management zones of different levels of human influence (managed, protected, strictly protected). This allowed for a comparison of spectral, temporal, and spatial disturbance patterns across a gradient from natural to coupled human and natural disturbances. Disturbance maps achieved overall accuracies ranging from 81% to 93%. Disturbance patches were generally small, with 95% of the disturbances being smaller than 10 ha. Disturbance rates ranged from 0.29% yr -1 to 0.95% yr -1 , and differed substantially among management zones and study sites. Natural disturbances in strictly protected areas were longer in duration (median of 8 years) and slightly less variable in magnitude compared to human-dominated disturbances in managed forests (median duration of 1 year). However, temporal dynamics between natural and human-dominated disturbances showed strong synchrony, suggesting that disturbance peaks are driven by natural events affecting managed and unmanaged areas simultaneously. Our study demonstrates the potential of remote sensing for mapping forest disturbances in coupled human and natural systems, such as the forests of Central Europe. Yet, we also highlight the complexity of such systems in

  7. Statistical methods for analysing responses of wildlife to human disturbance.

    Science.gov (United States)

    Haiganoush K. Preisler; Alan A. Ager; Michael J. Wisdom

    2006-01-01

    1. Off-road recreation is increasing rapidly in many areas of the world, and effects on wildlife can be highly detrimental. Consequently, we have developed methods for studying wildlife responses to off-road recreation with the use of new technologies that allow frequent and accurate monitoring of human-wildlife interactions. To illustrate these methods, we studied the...

  8. Managing human disturbance: factors influencing flight-initiation ...

    African Journals Online (AJOL)

    We tested how FID varied with group size, proximity to vegetation acting as protective cover, levels of human use, and survival rate, and whether these relationships varied by species. We collected 504 FIDs for seven bird species in Amurum Forest Reserve and its surrounding habitats (Jos, Nigeria). The FID was lower in ...

  9. Human-caused Disturbance Stimuli as a Form of Predation Risk

    Directory of Open Access Journals (Sweden)

    Alejandro Frid

    2002-06-01

    Full Text Available A growing number of studies quantify the impact of nonlethal human disturbance on the behavior and reproductive success of animals. Athough many are well designed and analytically sophisticated, most lack a theoretical framework for making predictions and for understanding why particular responses occur. Behavioral ecologists have recently begun to fill this theoretical vacuum by applying economic models of antipredator behavior to disturbance studies. In this emerging paradigm, predation and nonlethal disturbance stimuli create similar trade-offs between avoiding perceived risk and other fitness-enhancing activities, such as feeding, parental care, or mating. A vast literature supports the hypothesis that antipredator behavior has a cost to other activities, and that this trade-off is optimized when investment in antipredator behavior tracks short-term changes in predation risk. Prey have evolved antipredator responses to generalized threatening stimuli, such as loud noises and rapidly approaching objects. Thus, when encountering disturbance stimuli ranging from the dramatic, low-flying helicopter to the quiet wildlife photographer, animal responses are likely to follow the same economic principles used by prey encountering predators. Some authors have argued that, similar to predation risk, disturbance stimuli can indirectly affect fitness and population dynamics via the energetic and lost opportunity costs of risk avoidance. We elaborate on this argument by discussing why, from an evolutionary perspective, disturbance stimuli should be analogous to predation risk. We then consider disturbance effects on the behavior of individuals - vigilance, fleeing, habitat selection, mating displays, and parental investment - as well as indirect effects on populations and communities. A wider application of predation risk theory to disturbance studies should increase the generality of predictions and make mitigation more effective without over

  10. Insect avoidance may override human disturbances in reindeer habitat selection

    Directory of Open Access Journals (Sweden)

    Anna Skarin

    2004-04-01

    Full Text Available Habitat selection of semi-domesticated reindeer (Rangifer tarandus tarandus was investigated through faecal pellet- group counts and by direct observations of reindeer from helicopter in the Långfjället area in Idre reindeer herding district (62˚10’N and in Mittådalen reindeer herding district (62˚50’N, aerial observations only. Reindeer pellets were found to be most abundant in habitats at high altitudes, and in some vegetation types. Pellet-group densities tended to be higher near the tourist trails, which often follow higher altitudes in the terrain. The aerial surveys showed that the reindeer moved towards higher altitudes when the wind speed was low and the temperature was high both in June and July. In June they moved towards lower regions when temperature was low and the wind speed was strong. The conclusion is that the reindeer use Långfjället to escape insect harassment and warm weather, even though disturbance by tourism sometimes is high.Abstract in Swedish / Sammanfattning:Habitatval hos tamren (Rangifer tarandus tarandus undersöktes genom att göra en spillningsinventering och genom att göra flygobservationer från helikopter. Studien gjordes på Långfjället (62˚10’N i Idre nya sameby och i Mittådalens samebys sommarbetesområde (62˚50’N, endast flygobservationer. På Långfjället finns det vandringsleder som är frekventerade av vandrare från juni månad fram till september. Spillningen visade att renarna föredrog höjderna i området samt en del av vegetationstyperna. Det var också mer spillning närmare vandringslederna. Detta kan förklaras av att vandringslederna följer höjderna i terrängen. Flyginventeringarna under både juni och juli visade att renarna rörde sig mot högre terräng när det var varmt och lugnt väder. I juni rörde dom sig också i lägre terräng när det var stark vind och kallt väder. Slutsatsen är att renarna väljer att vistas i högre terräng för att undvika st

  11. Quantifying human disturbance in watersheds: Variable selection and performance of a GIS-based disturbance index for predicting the biological condition of perennial streams

    Science.gov (United States)

    Falcone, James A.; Carlisle, Daren M.; Weber, Lisa C.

    2010-01-01

    Characterizing the relative severity of human disturbance in watersheds is often part of stream assessments and is frequently done with the aid of Geographic Information System (GIS)-derived data. However, the choice of variables and how they are used to quantify disturbance are often subjective. In this study, we developed a number of disturbance indices by testing sets of variables, scoring methods, and weightings of 33 potential disturbance factors derived from readily available GIS data. The indices were calibrated using 770 watersheds located in the western United States for which the severity of disturbance had previously been classified from detailed local data by the United States Environmental Protection Agency (USEPA) Environmental Monitoring and Assessment Program (EMAP). The indices were calibrated by determining which variable or variable combinations and aggregation method best differentiated between least- and most-disturbed sites. Indices composed of several variables performed better than any individual variable, and best results came from a threshold method of scoring using six uncorrelated variables: housing unit density, road density, pesticide application, dam storage, land cover along a mainstem buffer, and distance to nearest canal/pipeline. The final index was validated with 192 withheld watersheds and correctly classified about two-thirds (68%) of least- and most-disturbed sites. These results provide information about the potential for using a disturbance index as a screening tool for a priori ranking of watersheds at a regional/national scale, and which landscape variables and methods of combination may be most helpful in doing so.

  12. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus.

    Directory of Open Access Journals (Sweden)

    Susannah S French

    Full Text Available The environment is currently undergoing changes at both global (e.g., climate change and local (e.g., tourism, pollution, habitat modification scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups for California sea lions (Zalophus californianus in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources. Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations.

  13. Electronic cigarettes: human health effects

    Science.gov (United States)

    Callahan-Lyon, Priscilla

    2014-01-01

    Objective With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Methods Literature searches were conducted through September 2013 using multiple electronic databases. Results Forty-four articles are included in this analysis. E-cigarette aerosols may contain propylene glycol, glycerol, flavourings, other chemicals and, usually, nicotine. Aerosolised propylene glycol and glycerol produce mouth and throat irritation and dry cough. No data on the effects of flavouring inhalation were identified. Data on short-term health effects are limited and there are no adequate data on long-term effects. Aerosol exposure may be associated with respiratory function impairment, and serum cotinine levels are similar to those in traditional cigarette smokers. The high nicotine concentrations of some products increase exposure risks for non-users, particularly children. The dangers of secondhand and thirdhand aerosol exposure have not been thoroughly evaluated. Conclusions Scientific evidence regarding the human health effects of e-cigarettes is limited. While e-cigarette aerosol may contain fewer toxicants than cigarette smoke, studies evaluating whether e-cigarettes are less harmful than cigarettes are inconclusive. Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking. No e-cigarette has been approved by FDA as a cessation aid. Environmental concerns and issues regarding non-user exposure exist. The health impact of e-cigarettes, for users and the public, cannot be determined with currently available data. PMID:24732161

  14. Electronic cigarettes: human health effects.

    Science.gov (United States)

    Callahan-Lyon, Priscilla

    2014-05-01

    With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components. Literature searches were conducted through September 2013 using multiple electronic databases. Forty-four articles are included in this analysis. E-cigarette aerosols may contain propylene glycol, glycerol, flavourings, other chemicals and, usually, nicotine. Aerosolised propylene glycol and glycerol produce mouth and throat irritation and dry cough. No data on the effects of flavouring inhalation were identified. Data on short-term health effects are limited and there are no adequate data on long-term effects. Aerosol exposure may be associated with respiratory function impairment, and serum cotinine levels are similar to those in traditional cigarette smokers. The high nicotine concentrations of some products increase exposure risks for non-users, particularly children. The dangers of secondhand and thirdhand aerosol exposure have not been thoroughly evaluated. Scientific evidence regarding the human health effects of e-cigarettes is limited. While e-cigarette aerosol may contain fewer toxicants than cigarette smoke, studies evaluating whether e-cigarettes are less harmful than cigarettes are inconclusive. Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking. No e-cigarette has been approved by FDA as a cessation aid. Environmental concerns and issues regarding non-user exposure exist. The health impact of e-cigarettes, for users and the public, cannot be determined with currently available data.

  15. Simulation of electron density disturbances of the ionospheric D region produced by high-energy particle fluxes

    International Nuclear Information System (INIS)

    Martynenko, S.I.

    1989-01-01

    Using the large-scale tim expansion analytical solutions of electron concentration balance equation in D-region of the ionosphere for pulsed and periodic changes in the rate of ion formatin under the effect of fluxes of precipitating high-energy particles are obtained. Possible effect of disturbances of temperature of nutrals is taken into account. On the basis of model representations the space-time structure of emerging ionospheric disturbances is discussed

  16. Human disturbance is a major determinant of wildlife distribution in Himalayan midhill landscapes of Nepal

    Czech Academy of Sciences Publication Activity Database

    Paudel, Prakash K.; Kindlmann, Pavel

    2012-01-01

    Roč. 15, č. 3 (2012), s. 283-293 ISSN 1367-9430 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : human disturbance * midhills * wildlife conservation * mountain landscape * conservation challenges Subject RIV: EH - Ecology, Behaviour Impact factor: 2.692, year: 2012

  17. Using spontaneous succession for restoration of human-disturbed habitats: experience from Central Europe

    Czech Academy of Sciences Publication Activity Database

    Prach, Karel; Pyšek, Petr

    2001-01-01

    Roč. 17, - (2001), s. 55-62 ISSN 0925-8574 R&D Projects: GA ČR GA206/94/0395; GA ČR GA206/97/0077 Institutional research plan: CEZ:AV0Z6005908 Keywords : vegetation * succession * human-disturbed habitats Subject RIV: DO - Wilderness Conservation Impact factor: 0.601, year: 2001

  18. Heart rate responses provide an objective evaluation of human disturbance stimuli in breeding birds.

    Science.gov (United States)

    Ellenberg, Ursula; Mattern, Thomas; Seddon, Philip J

    2013-01-01

    Intuition is a poor guide for evaluating the effects of human disturbance on wildlife. Using the endangered Yellow-eyed penguin, Megadyptes antipodes, as an example, we show that heart rate responses provide an objective tool to evaluate human disturbance stimuli and encourage the wider use of this simple and low-impact approach. Yellow-eyed penguins are a flagship species for New Zealand's wildlife tourism; however, unregulated visitor access has recently been associated with reduced breeding success and lower first year survival. We measured heart rate responses of Yellow-eyed penguins via artificial eggs to evaluate a range of human stimuli regularly occurring at their breeding sites. We found the duration of a stimulus to be the most important factor, with elevated heart rate being sustained while a person remained within sight. Human activity was the next important component; a simulated wildlife photographer, crawling slowly around during his stay, elicited a significantly higher heart rate response than an entirely motionless human spending the same time at the same distance. Stimuli we subjectively might perceive as low impact, such as the careful approach of a 'wildlife photographer', resulted in a stronger response than a routine nest-check that involved lifting a bird up to view nest contents. A single, slow-moving human spending 20 min within 2 m from the nest may provoke a response comparable to that of 10 min handling a bird for logger deployment. To reduce cumulative impact of disturbance, any human presence in the proximity of Yellow-eyed penguins needs to be kept at a minimum. Our results highlight the need for objective quantification of the effects of human disturbance in order to provide a sound basis for guidelines to manage human activity around breeding birds.

  19. Path integral approach for electron transport in disturbed magnetic field lines

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, Ryutaro; Nakajima, Noriyoshi; Takamaru, Hisanori

    2002-05-01

    A path integral method is developed to investigate statistical property of an electron transport described as a Langevin equation in a statically disturbed magnetic field line structure; especially a transition probability of electrons strongly tied to field lines is considered. The path integral method has advantages that 1) it does not include intrinsically a growing numerical error of an orbit, which is caused by evolution of the Langevin equation under a finite calculation accuracy in a chaotic field line structure, and 2) it gives a method of understanding the qualitative content of the Langevin equation and assists to expect statistical property of the transport. Monte Carlo calculations of the electron distributions under both effects of chaotic field lines and collisions are demonstrated to comprehend above advantages through some examples. The mathematical techniques are useful to study statistical properties of various phenomena described as Langevin equations in general. By using parallel generators of random numbers, the Monte Carlo scheme to calculate a transition probability can be suitable for a parallel computation. (author)

  20. Human error as a source of disturbances in Swedish nuclear power plants

    International Nuclear Information System (INIS)

    Sokolowski, E.

    1985-01-01

    Events involving human errors at the Swedish nuclear power plants are registered and periodically analyzed. The philosophy behind the scheme for data collection and analysis is discussed. Human errors cause about 10% of the disturbances registered. Only a small part of these errors are committed by operators in the control room. These and other findings differ from those in other countries. Possible reasons are put forward

  1. Coping with continuous human disturbance in the wild: insights from penguin heart rate response to various stressors.

    OpenAIRE

    Viblanc, V.A.; Smith, A.D.; Gineste, B.; Groscolas, R.

    2012-01-01

    Abstract Background A central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism) might impact wildlife and affect the systems under study. From a research perspective, identifying the effects of human disturbance caused by research-related activities is crucial in order to understand and account for potential biases and derive appropriate conclusions from the data. Results Here, we document a case of biological adjustment to chronic human disturbance in a...

  2. Behavioural strategies towards human disturbances explain individual performance in woodland caribou.

    Science.gov (United States)

    Leclerc, Martin; Dussault, Christian; St-Laurent, Martin-Hugues

    2014-09-01

    Behavioural strategies may have important fitness, ecological and evolutionary consequences. In woodland caribou, human disturbances are associated with higher predation risk. Between 2004 and 2011, we investigated if habitat selection strategies of female caribou towards disturbances influenced their calf's survival in managed boreal forest with varying intensities of human disturbances. Calf survival was 53% and 43% after 30 and 90 days following birth, respectively, and 52% of calves that died were killed by black bear. The probability that a female lose its calf to predation was not influenced by habitat composition of her annual home range, but decreased with an increase in proportion of open lichen woodland within her calving home range. At the local scale, females that did not lose their calf displayed stronger avoidance of high road density areas than females that lost their calf to predation. Further, females that lost their calf to predation and that had a low proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas where these young cutovers were locally absent. Also, females that lost their calf to predation and that had a high proportion of ≤5-year-old cutovers within their calving home range were mostly observed in areas with a high local density of ≤5-year-old cutovers. Our study demonstrates that we have to account for human-induced disturbances at both local and regional scales in order to further enhance effective caribou management plans. We demonstrate that disturbances not only impact spatial distribution of individuals, but also their reproductive success.

  3. Time delay and duration of ionospheric total electron content responses to geomagnetic disturbances

    Directory of Open Access Journals (Sweden)

    J. Liu

    2010-03-01

    Full Text Available Although positive and negative signatures of ionospheric storms have been reported many times, global characteristics such as the time of occurrence, time delay and duration as well as their relations to the intensity of the ionospheric storms have not received enough attention. The 10 years of global ionosphere maps (GIMs of total electron content (TEC retrieved at Jet Propulsion Laboratory (JPL were used to conduct a statistical study of the time delay of the ionospheric responses to geomagnetic disturbances. Our results show that the time delays between geomagnetic disturbances and TEC responses depend on season, magnetic local time and magnetic latitude. In the summer hemisphere at mid- and high latitudes, the negative storm effects can propagate to the low latitudes at post-midnight to the morning sector with a time delay of 4–7 h. As the earth rotates to the sunlight, negative phase retreats to higher latitudes and starts to extend to the lower latitude toward midnight sector. In the winter hemisphere during the daytime and after sunset at mid- and low latitudes, the negative phase appearance time is delayed from 1–10 h depending on the local time, latitude and storm intensity compared to the same area in the summer hemisphere. The quick response of positive phase can be observed at the auroral area in the night-side of the winter hemisphere. At the low latitudes during the dawn-noon sector, the ionospheric negative phase responses quickly with time delays of 5–7 h in both equinoctial and solsticial months.

    Our results also manifest that there is a positive correlation between the intensity of geomagnetic disturbances and the time duration of both the positive phase and negative phase. The durations of both negative phase and positive phase have clear latitudinal, seasonal and magnetic local time (MLT dependence. In the winter hemisphere, long durations for the positive phase are 8–11 h and 12–14 h during the daytime at

  4. Time delay and duration of ionospheric total electron content responses to geomagnetic disturbances

    Directory of Open Access Journals (Sweden)

    J. Liu

    2010-03-01

    Full Text Available Although positive and negative signatures of ionospheric storms have been reported many times, global characteristics such as the time of occurrence, time delay and duration as well as their relations to the intensity of the ionospheric storms have not received enough attention. The 10 years of global ionosphere maps (GIMs of total electron content (TEC retrieved at Jet Propulsion Laboratory (JPL were used to conduct a statistical study of the time delay of the ionospheric responses to geomagnetic disturbances. Our results show that the time delays between geomagnetic disturbances and TEC responses depend on season, magnetic local time and magnetic latitude. In the summer hemisphere at mid- and high latitudes, the negative storm effects can propagate to the low latitudes at post-midnight to the morning sector with a time delay of 4–7 h. As the earth rotates to the sunlight, negative phase retreats to higher latitudes and starts to extend to the lower latitude toward midnight sector. In the winter hemisphere during the daytime and after sunset at mid- and low latitudes, the negative phase appearance time is delayed from 1–10 h depending on the local time, latitude and storm intensity compared to the same area in the summer hemisphere. The quick response of positive phase can be observed at the auroral area in the night-side of the winter hemisphere. At the low latitudes during the dawn-noon sector, the ionospheric negative phase responses quickly with time delays of 5–7 h in both equinoctial and solsticial months. Our results also manifest that there is a positive correlation between the intensity of geomagnetic disturbances and the time duration of both the positive phase and negative phase. The durations of both negative phase and positive phase have clear latitudinal, seasonal and magnetic local time (MLT dependence. In the winter hemisphere, long durations for the positive phase are 8–11 h and 12–14 h during the daytime at middle

  5. Butterfly community assemblages in relation to human disturbance in a tropical upland forest in Ghana, and implications for conservation

    Directory of Open Access Journals (Sweden)

    Patrick Addo-Fordjour

    2015-04-01

    Full Text Available The present study determined butterfly diversity, species composition and abundance in different forests of varying human disturbance intensities in the Atewa Range Forest Reserve, Ghana (i.e. non-disturbed, moderately disturbed and heavily disturbed forests. Vegetation characteristics and butterflies were sampled within ten 50 m × 50 m plots in each forest type. The study revealed that butterfly Shannon diversity index was similar in the non-disturbed and moderately disturbed forests although it was significantly lower in the heavily disturbed forest. Butterfly abundance differed significantly among all the forest types. Significant relationships were detected between some vegetation characteristics, and butterfly diversity and abundance (P<0.001. Using Non-metric Multidimensional Scaling (NMDS and cluster analysis, three main butterfly assemblages were identified on the basis of species composition, with each one in a particular forest type. Furthermore, butterfly species composition differed significantly among the forest types (ANOSIM; P<0.0001. The intermediate form of human disturbance in the moderately disturbed forest maintained butterfly diversity, suggesting that management efforts aimed at butterfly conservation should be geared towards protecting forests from excessive human disturbance; selective logging is recommended.

  6. Chronic human disturbance affects plant trait distribution in a seasonally dry tropical forest

    Science.gov (United States)

    Sfair, Julia C.; de Bello, Francesco; de França, Thaysa Q.; Baldauf, Cristina; Tabarelli, Marcelo

    2018-02-01

    The effects of human disturbance on biodiversity can be mediated by environmental conditions, such as water availability, climate and nutrients. In general, disturbed, dry or nutrient-depleted soils areas tend to have lower taxonomic diversity. However, little is known about how these environmental conditions affect functional composition and intraspecific variability in tropical dry forests. We studied a seasonally dry tropical forest (SDTF) under chronic anthropogenic disturbance (CAD) along rainfall and soil nutrient gradients to understand how these factors influence the taxonomic and functional composition. Specifically we evaluated two aspects of CAD, wood extraction and livestock pressure (goat and cattle grazing), along soil fertility and rainfall gradients on shrub and tree traits, considering species turnover and intraspecific variability. In addition, we also tested how the traits of eight populations of the most frequent species are affected by wood extraction, livestock pressure, rainfall and soil fertility. In general, although CAD and environmental gradients affected each trait of the most widespread species differently, the most abundant species also had a greater variation of traits. Considering species turnover, wood extraction is associated with species with a smaller leaf area and lower investment in leaf mass, probably due to the indirect effects of this disturbance type on the vegetation, i.e. the removal of branches and woody debris clears the vegetation, favouring species that minimize water loss. Livestock pressure, on the other hand, affected intraspecific variation: the herbivory caused by goats and cattle promoted individuals which invest more in wood density and leaf mass. In this case, the change of functional composition observed is a direct effect of the disturbance, such as the decrease of palatable plant abundance by goat and cattle herbivory. In synthesis, CAD, rainfall and soil fertility can affect trait distribution at community

  7. Human disturbances and predation on artificial ground nests across an urban gradient

    OpenAIRE

    Bocz, R.; Szép, D.; Witz, D.; Ronczyk, L.; Kurucz, K.; Purger, J. J.

    2017-01-01

    In our study with artificial nests we observed that the absence of ground nesting bird species in the city centre and in residential districts was due to disturbance by humans and domestic animals (dogs and cats) rather than to predation. Furthermore, predation pressure was higher in the outskirts of the city due to the greater number of natural predators. Our results suggest that planning and creating undisturbed areas could increase the chances of ground nesting birds settling and breeding ...

  8. Demographics of an ornate box turtle population experiencing minimal human-induced disturbances

    Science.gov (United States)

    Converse, S.J.; Iverson, J.B.; Savidge, J.A.

    2005-01-01

    Human-induced disturbances may threaten the viability of many turtle populations, including populations of North American box turtles. Evaluation of the potential impacts of these disturbances can be aided by long-term studies of populations subject to minimal human activity. In such a population of ornate box turtles (Terrapene ornata ornata) in western Nebraska, we examined survival rates and population growth rates from 1981-2000 based on mark-recapture data. The average annual apparent survival rate of adult males was 0.883 (SE = 0.021) and of adult females was 0.932 (SE = 0.014). Minimum winter temperature was the best of five climate variables as a predictor of adult survival. Survival rates were highest in years with low minimum winter temperatures, suggesting that global warming may result in declining survival. We estimated an average adult population growth rate (????) of 1.006 (SE = 0.065), with an estimated temporal process variance (????2) of 0.029 (95% CI = 0.005-0.176). Stochastic simulations suggest that this mean and temporal process variance would result in a 58% probability of a population decrease over a 20-year period. This research provides evidence that, unless unknown density-dependent mechanisms are operating in the adult age class, significant human disturbances, such as commercial harvest or turtle mortality on roads, represent a potential risk to box turtle populations. ?? 2005 by the Ecological Society of America.

  9. Spindle disturbances in human-hamster hybrid (AL) cells induced by mobile communication frequency range signals.

    Science.gov (United States)

    Schrader, Thorsten; Münter, Klaus; Kleine-Ostmann, Thomas; Schmid, Ernst

    2008-12-01

    The production of spindle disturbances in FC2 cells, a human-hamster hybrid (A(L)) cell line, by non-ionizing radiation was studied using an electromagnetic field with a field strength of 90 V/m at a frequency of 835 MHz. Due to the given experimental conditions slide flask cultures were exposed at room temperature in a microTEM (transversal electromagnetic field) cell, which allows optimal experimental conditions for small samples of biological material. Numerical calculations suggest that specific absorption rates of up to 60 mW/kg are reached for maximum field exposure. All exposure field parameters--either measured or calculable--are precisely defined and, for the first time, traceable to the standards of the SI system of physical units. Compared with co-incident negative controls, the results of two independently performed experiments suggest that exposure periods of time from 0.5 to 2 h with an electric field strength of 90 V/m are spindle acting agents as predominately indicated by the appearance of spindle disturbances at the ana- and telophase stages (especially lagging and non-disjunction of single chromosomes) of cell divisions. The spindle disturbances do not change the fraction of mitotic cells with increasing exposure time up to 2 h. Due to the applied experimental conditions an influence of temperature as a confounder parameter for spindle disturbances can be excluded.

  10. NMR studies of transmembrane electron transport in human erythrocytes

    International Nuclear Information System (INIS)

    Kennett, E.C.; Bubb, W.A.; Kuchel, P.W.

    2002-01-01

    Full text: Electron transport systems exist in the plasma membranes of all cells. These systems appear to play a role in cell growth and proliferation, intracellular signalling, hormone responses, apoptotic events, cell defence and perhaps most importantly they enable the cell to respond to changes in the redox state of both the intra- and extracellular environments. Previously, 13 C NMR has been used to study transmembrane electron transport in human erythrocytes, specifically the reduction of extracellular 13 C-ferricyanide. NMR is a particularly useful tool for studying such systems as changes in the metabolic state of the cell can be observed concomitantly with extracellular reductase activity. We investigated the oxidation of extracellular NADH by human erythrocytes using 1 H and 31 P NMR spectroscopy. Recent results for glucose-starved human erythrocytes indicate that, under these conditions, extracellular NADH can be oxidised at the plasma membrane with the electron transfer across the membrane resulting in reduction of intracellular NAD + . The activity is inhibited by known trans-plasma membrane electron transport inhibitors (capsaicin and atebrin) and is unaffected by inhibition of the erythrocyte Band 3 anion transporter. These results suggest that electron import from extracellular NADH allows the cell to re-establish a reducing environment after the normal redox balance is disturbed

  11. Human Disturbance during Early Life Impairs Nestling Growth in Birds Inhabiting a Nature Recreation Area.

    Science.gov (United States)

    Remacha, Carolina; Delgado, Juan Antonio; Bulaic, Mateja; Pérez-Tris, Javier

    2016-01-01

    Nature recreation conflicts with conservation, but its impacts on wildlife are not fully understood. Where recreation is not regulated, visitors to natural areas may gather in large numbers on weekends and holidays. This may increase variance in fitness in wild populations, if individuals whose critical life cycle stages coincide with periods of high human disturbance are at a disadvantage. We studied nestling development of blue tits (Cyanistes caeruleus) in a natural area where recreation activities intensify during weekends and other public holidays at picnic and leisure facilities, but not in the surrounding woods. In nests located near recreation facilities, blue tit nestlings that hatched during holidays developed slowly, and fledged with low body mass and poor body condition. However, nestlings that hatched outside of holidays and weekends in these nest boxes developed normally, eventually attaining similar phenotypes as those hatching in the surrounding woods. Within-brood variance in body mass was also higher in broods that began growing during holidays in disturbed areas. Our results show that early disturbance events may have negative consequences for wild birds if they overlap with critical stages of development, unveiling otherwise cryptic impacts of human activities. These new findings may help managers better regulate nature recreation.

  12. Human Disturbance during Early Life Impairs Nestling Growth in Birds Inhabiting a Nature Recreation Area.

    Directory of Open Access Journals (Sweden)

    Carolina Remacha

    Full Text Available Nature recreation conflicts with conservation, but its impacts on wildlife are not fully understood. Where recreation is not regulated, visitors to natural areas may gather in large numbers on weekends and holidays. This may increase variance in fitness in wild populations, if individuals whose critical life cycle stages coincide with periods of high human disturbance are at a disadvantage. We studied nestling development of blue tits (Cyanistes caeruleus in a natural area where recreation activities intensify during weekends and other public holidays at picnic and leisure facilities, but not in the surrounding woods. In nests located near recreation facilities, blue tit nestlings that hatched during holidays developed slowly, and fledged with low body mass and poor body condition. However, nestlings that hatched outside of holidays and weekends in these nest boxes developed normally, eventually attaining similar phenotypes as those hatching in the surrounding woods. Within-brood variance in body mass was also higher in broods that began growing during holidays in disturbed areas. Our results show that early disturbance events may have negative consequences for wild birds if they overlap with critical stages of development, unveiling otherwise cryptic impacts of human activities. These new findings may help managers better regulate nature recreation.

  13. Solent Disturbance and Mitigation Project Phase II: Predicting the impact of human disturbance on overwintering birds in the Solent.

    OpenAIRE

    Stillman, Richard A.; West, Andrew D.; Clarke, Ralph T.; Liley, D.

    2012-01-01

    The Solent coastline provides feeding grounds for internationally protected populations of overwintering waders and wildfowl, and is also extensively used for recreation. In response to concerns over the impact of recreational pressure on birds within protected areas in the Solent, the Solent Forum initiated the Solent Disturbance and Mitigation Project to determine visitor access patterns around the coast and how their activities may influence the birds. The project has been divided into two...

  14. Historical landscape elements in preserving steppic species - vegetation responses on micro-topography and human disturbances

    Science.gov (United States)

    Deák, Balázs; Valkó, Orsolya; Török, Péter; Tóthmérész, Béla

    2017-04-01

    Land use changes of past centuries resulted in a considerable loss and isolation of grassland habitats worldwide which also led to a serious loss in ecosystem functions. In intensively used agricultural landscapes remnants of natural flora persisted only in small habitat islands embedded in a hostile matrix, which are inadequate for arable farming or construction. In the steppe zone of Eurasia burial mounds, so-called kurgans, have a great potential to preserve the natural flora and habitats and act as local biodiversity hotspots. Their special micro-topography and historical origin makes kurgans characteristic landscape elements of the steppe region. These features also result in a specific soil development and micro-climate, which makes kurgans especially adequate habitats for several steppe specialist plant species. Furthermore, they are proper objects for studying the effects of present and past human disturbances on the vegetation of semi-natural habitats. Exploration of the main factors driving biodiversity in isolated habitat fragments is crucial for understanding the ecological processes shaping their vegetation and for designing effective strategies for their protection. We surveyed the vegetation of 44 isolated kurgans in East-Hungary and studied the effects of habitat area, slope, recent disturbance, past destruction and the level of woody encroachment on the species richness and cover of grassland specialist and weedy species. We used model selection techniques and linear models for testing relevant factors affecting specialist species in grassland fragments. We found that the biodiversity conservation potential of kurgans is supported by their steep slopes, which provide adequate habitat conditions and micro-climate for steppic specialist plant species. By harbouring several grassland specialist species, kurgans have a great potential for preserving the natural species pool of even considerably altered agricultural landscapes, and can mitigate the

  15. Human disturbances on coral reefs in Sri Lanka: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, M C; Linden, O [Stockholm Univ. (Sweden). Dept. of Zoology; Rajasuriya, A [NARA, Crow Island, Colombo (Sri Lanka)

    1993-01-01

    The degradation of coral reefs in Sri Lanka has increased substantially over the last decades. Human activities causing this degradation include: mining for lime production, sewage discharges, discharges of oil and other pollutants in connection with shipping and port activities, destructive fishing practices, land and mangrove destruction, tourism and the collecting of fauna such as fish, shells and corals. In this study, three adjacent coral reefs; Bar Reef, Talawila Reef, and Kandakuliya Reef, which are widely scattered patch reefs off Kalpitiya Peninsula, northwestern Sri Lanka, were surveyed and compared in terms of their fish and coral diversity and abundance as well as human and natural disturbances. Information was gathered by snorkeling in visual overview surveys and by scuba diving in detailed transect surveys. When each reef was ranked according to the extent of live coral cover, and chaetodontid diversity, the results indicated that Bar Reef was in excellent condition, Talawila Reef was intermediate, and Kandakuliya Reef was in poor condition. The diversity of coral genera, the topographic relief and the proportion of coral rubble, did not follow the same pattern. The number of coral genera found was 49, while 283 fish species belonging to 51 families were recorded. Human disturbance factors on the reefs were found to be net fishing, boat anchoring and ornamental fish collection for the aquarium trade. Bottom.set nylon nets in particular were found to have a very destructive impact on the bottom fauna. 33 refs, 7 figs, 1 tab

  16. Human disturbances and predation on artificial ground nests across an urban gradient

    Directory of Open Access Journals (Sweden)

    Bocz, R.

    2017-03-01

    Full Text Available In our study with artificial nests we observed that the absence of ground nesting bird species in the city centre and in residential districts was due to disturbance by humans and domestic animals (dogs and cats rather than to predation. Furthermore, predation pressure was higher in the outskirts of the city due to the greater number of natural predators. Our results suggest that planning and creating undisturbed areas could increase the chances of ground nesting birds settling and breeding in human–dominated landscapes.

  17. Coping with continuous human disturbance in the wild: insights from penguin heart rate response to various stressors.

    Science.gov (United States)

    Viblanc, Vincent A; Smith, Andrew D; Gineste, Benoit; Groscolas, René

    2012-07-11

    A central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism) might impact wildlife and affect the systems under study. From a research perspective, identifying the effects of human disturbance caused by research-related activities is crucial in order to understand and account for potential biases and derive appropriate conclusions from the data. Here, we document a case of biological adjustment to chronic human disturbance in a colonial seabird, the king penguin (Aptenodytes patagonicus), breeding on remote and protected islands of the Southern ocean. Using heart rate (HR) as a measure of the stress response, we show that, in a colony with areas exposed to the continuous presence of humans (including scientists) for over 50 years, penguins have adjusted to human disturbance and habituated to certain, but not all, types of stressors. When compared to birds breeding in relatively undisturbed areas, birds in areas of high chronic human disturbance were found to exhibit attenuated HR responses to acute anthropogenic stressors of low-intensity (i.e. sounds or human approaches) to which they had been subjected intensely over the years. However, such attenuation was not apparent for high-intensity stressors (i.e. captures for scientific research) which only a few individuals experience each year. Habituation to anthropogenic sounds/approaches could be an adaptation to deal with chronic innocuous stressors, and beneficial from a research perspective. Alternately, whether penguins have actually habituated to anthropogenic disturbances over time or whether human presence has driven the directional selection of human-tolerant phenotypes, remains an open question with profound ecological and conservation implications, and emphasizes the need for more knowledge on the effects of human disturbance on long-term studied populations.

  18. Coping with continuous human disturbance in the wild: insights from penguin heart rate response to various stressors

    Directory of Open Access Journals (Sweden)

    Viblanc Vincent A

    2012-07-01

    Full Text Available Abstract Background A central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism might impact wildlife and affect the systems under study. From a research perspective, identifying the effects of human disturbance caused by research-related activities is crucial in order to understand and account for potential biases and derive appropriate conclusions from the data. Results Here, we document a case of biological adjustment to chronic human disturbance in a colonial seabird, the king penguin (Aptenodytes patagonicus, breeding on remote and protected islands of the Southern ocean. Using heart rate (HR as a measure of the stress response, we show that, in a colony with areas exposed to the continuous presence of humans (including scientists for over 50 years, penguins have adjusted to human disturbance and habituated to certain, but not all, types of stressors. When compared to birds breeding in relatively undisturbed areas, birds in areas of high chronic human disturbance were found to exhibit attenuated HR responses to acute anthropogenic stressors of low-intensity (i.e. sounds or human approaches to which they had been subjected intensely over the years. However, such attenuation was not apparent for high-intensity stressors (i.e. captures for scientific research which only a few individuals experience each year. Conclusions Habituation to anthropogenic sounds/approaches could be an adaptation to deal with chronic innocuous stressors, and beneficial from a research perspective. Alternately, whether penguins have actually habituated to anthropogenic disturbances over time or whether human presence has driven the directional selection of human-tolerant phenotypes, remains an open question with profound ecological and conservation implications, and emphasizes the need for more knowledge on the effects of human disturbance on long-term studied populations.

  19. Diversity loss with persistent human disturbance increases vulnerability to ecosystem collapse.

    Science.gov (United States)

    MacDougall, A S; McCann, K S; Gellner, G; Turkington, R

    2013-02-07

    Long-term and persistent human disturbances have simultaneously altered the stability and diversity of ecological systems, with disturbances directly reducing functional attributes such as invasion resistance, while eliminating the buffering effects of high species diversity. Theory predicts that this combination of environmental change and diversity loss increases the risk of abrupt and potentially irreversible ecosystem collapse, but long-term empirical evidence from natural systems is lacking. Here we demonstrate this relationship in a degraded but species-rich pyrogenic grassland in which the combined effects of fire suppression, invasion and trophic collapse have created a species-poor grassland that is highly productive, resilient to yearly climatic fluctuations, and resistant to invasion, but vulnerable to rapid collapse after the re-introduction of fire. We initially show how human disturbance has created a negative relationship between diversity and function, contrary to theoretical predictions. Fire prevention since the mid-nineteenth century is associated with the loss of plant species but it has stabilized high-yield annual production and invasion resistance, comparable to a managed high-yield low-diversity agricultural system. In managing for fire suppression, however, a hidden vulnerability to sudden environmental change emerges that is explained by the elimination of the buffering effects of high species diversity. With the re-introduction of fire, grasslands only persist in areas with remnant concentrations of native species, in which a range of rare and mostly functionally redundant plants proliferate after burning and prevent extensive invasion including a rapid conversion towards woodland. This research shows how biodiversity can be crucial for ecosystem stability despite appearing functionally insignificant beforehand, a relationship probably applicable to many ecosystems given the globally prevalent combination of intensive long-term land

  20. Historical biome distribution and recent human disturbance shape the diversity of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Pärtel, Meelis; Öpik, Maarja; Moora, Mari; Tedersoo, Leho; Szava-Kovats, Robert; Rosendahl, Søren; Rillig, Matthias C; Lekberg, Ylva; Kreft, Holger; Helgason, Thorunn; Eriksson, Ove; Davison, John; de Bello, Francesco; Caruso, Tancredi; Zobel, Martin

    2017-10-01

    The availability of global microbial diversity data, collected using standardized metabarcoding techniques, makes microorganisms promising models for investigating the role of regional and local factors in driving biodiversity. Here we modelled the global diversity of symbiotic arbuscular mycorrhizal (AM) fungi using currently available data on AM fungal molecular diversity (small subunit (SSU) ribosomal RNA (rRNA) gene sequences) in field samples. To differentiate between regional and local effects, we estimated species pools (sets of potentially suitable taxa) for each site, which are expected to reflect regional processes. We then calculated community completeness, an index showing the fraction of the species pool present, which is expected to reflect local processes. We found significant spatial variation, globally in species pool size, as well as in local and dark diversity (absent members of the species pool). Species pool size was larger close to areas containing tropical grasslands during the last glacial maximum, which are possible centres of diversification. Community completeness was greater in regions of high wilderness (remoteness from human disturbance). Local diversity was correlated with wilderness and current connectivity to mountain grasslands. Applying the species pool concept to symbiotic fungi facilitated a better understanding of how biodiversity can be jointly shaped by large-scale historical processes and recent human disturbance. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  1. Energetic electron precipitation and VLF phase disturbances at middle latitudes following the magnetic storm of December 6, 1971

    International Nuclear Information System (INIS)

    Larsen, T.R.; Potemra, T.A.; Imhof, W.L.; Reagan, J.B.

    1977-01-01

    Enhanced fluxes of electrons precipitating over middle latitudes (L approx. 3--4) were detected by the polar-orbiting satellite 1971-089A following a period of magnetic activity starting on December 16, 1971. The electron fluxes measured in 256 differential channels between 130 and 2800 keV have been coordinated with phase observations of VLF radio waves propagating in the earth-ionosphere waveguide. The VLF paths in question, NLK (near Seattle, Washington) and GBR (at Rugby, England) to APL (near Washington, D. C.), cover approx. =120 0 in longitude and range from L approx. 2.5 to L approx. 4.0 in invariant latitude. These paths showed marked daytime and nighttime phase advances from 1650 UT on December 17 (in excess of 10 μs during maximum disturbance). The phase values did not return to prestorm levels before December 22--23. The unusual presence of these daytime VLF disturbances is offered as evidence for the widespread precipitation at low L shell vales of nearly relativistic electrons (E/sub e/> approx.200 keV) which would be required to penetrate below approx.70-km altitude to affect the daytime VLF transmissions. Wave guide mode calculations using D region electron density profiles deduced from the satellite particle data predict phase advances which agree reasonably well with the observed values. It is concluded that the observed long-lived VLF phase disturbances can be explained by excess D region ionization caused by energetic electrons precipitating from the earth's radiation belt following their injection deep into the magnetosphere during the magnetic storm

  2. Catchment controls and human disturbances on the geomorphology of small Mediterranean estuarine systems

    Science.gov (United States)

    Estrany, Joan; Grimalt, Miquel

    2014-10-01

    Geographic signatures are physical and human-induced characteristics or processes that identify comparable or unique features of estuaries along latitudinal gradients. In Mediterranean areas, the microtidal regime and the strong seasonal and inter-annual contrasts cause an alternation between relatively high runoff and arid conditions. Furthermore, the long history of human settlement also increases the complexity in the study of these estuarine systems. This study investigates these signatures of the estuaries located within the Mallorcan eastern coast, which are geomorphologically homogeneous because of a similar bedrock geology and Holocene history. A multi-method approach focused on the integration of geomorphometry, hydraulics, historical sources and statistics was used. We explore the role played by catchment morphometric parameters, severe flash flood events and human disturbances in controlling the geomorphology of 10 beach-barrier enclosed, fluvial incised lagoons. Most of the lagoons discharge into 'calas', ranging in size from 1345 to 17,537 m2 and their related catchments are representative of the Mediterranean hydrological systems. Multiple regression models illustrate that the size, slope and drainage network development of the catchments explain the variance in length (r2 = 0.67), volume (r2 = 0.49), area (r2 = 0.64), circularity (r2 = 0.72) and average width (r2 = 0.81) of the lagoons. Depending on these catchment morphometric variables, the shape of the lagoons is also determined by the occurrence of catastrophic flash floods, which cause scouring and dredging, whereas the ordinary flood events and sea storms promote refilling and sedimentation. A historical analysis since 1850 documented 18 flood events, 5 of which were catastrophic with destructive effects along the catchments and large morphological changes in coastal lagoons. High intensity rainfall (up to 200 mm in 2 h), the geomorphometry of the catchments and the massive construction of

  3. Acid sulphate soil disturbance and metals in groundwater: Implications for human exposure through home grown produce

    International Nuclear Information System (INIS)

    Hinwood, Andrea Lee; Horwitz, Pierre; Appleyard, Steve; Barton, Caroline; Wajrak, Magda

    2006-01-01

    A significant emerging environmental problem is the disturbance and oxidation of soils with high levels of iron sulphide minerals resulting in acidification and causing the mobilization of metals into groundwater. This process is occurring in many parts of the world. In Western Australia, impacted groundwater is extracted by residents for domestic use. We sought to establish domestic use patterns of bore water and the concentration of metals. Sixty-seven domestic bore water samples clearly indicated oxidation of sulphidic materials with heavy metal concentrations ranging for aluminium (< DL-37.0 mg/L), arsenic (< DL-6.6 mg/L), iron (< DL-1200 mg/L), cadmium (< DL-0.021 mg/L), lead (< DL-0.040 mg/L), selenium (< DL-0.006 mg/L). A high proportion of residents used bore water on home grown produce. The study suggests that there is potential for human exposure to heavy metals via the consumption of home grown produce. This warrants further investigation in light of increasing acid sulphate soil disturbance in many locations. - Acidified bore water may introduce metals into produce for home consumption

  4. Dealing with Magnetic Disturbances in Human Motion Capture: A Survey of Techniques

    Directory of Open Access Journals (Sweden)

    Gabriele Ligorio

    2016-03-01

    Full Text Available Magnetic-Inertial Measurement Units (MIMUs based on microelectromechanical (MEMS technologies are widespread in contexts such as human motion tracking. Although they present several advantages (lightweight, size, cost, their orientation estimation accuracy might be poor. Indoor magnetic disturbances represent one of the limiting factors for their accuracy, and, therefore, a variety of work was done to characterize and compensate them. In this paper, the main compensation strategies included within Kalman-based orientation estimators are surveyed and classified according to which degrees of freedom are affected by the magnetic data and to the magnetic disturbance rejection methods implemented. By selecting a representative method from each category, four algorithms were obtained and compared in two different magnetic environments: (1 small workspace with an active magnetic source; (2 large workspace without active magnetic sources. A wrist-worn MIMU was used to acquire data from a healthy subject, whereas a stereophotogrammetric system was adopted to obtain ground-truth data. The results suggested that the model-based approaches represent the best compromise between the two testbeds. This is particularly true when the magnetic data are prevented to affect the estimation of the angles with respect to the vertical direction.

  5. Dependability in electronic systems mitigation of hardware failures, soft errors, and electro-magnetic disturbances

    CERN Document Server

    Kanekawa, Nobuyasu; Suga, Takashi; Uematsu, Yutaka

    2011-01-01

    Dependability in Electronic Systems presents practical applications for dependable electronic systems, such as train control, automotive control systems and network servers/routers. Readers will find an overview of dependability, enabling them to select the best choice for maximum results.

  6. Effects of human disturbance on waterbird nesting and reproductive success at restoration pond SF2, south San Francisco Bay, California

    Science.gov (United States)

    Ackerman, Joshua T.; Herzog, Mark P.; Hartman, Christopher A.

    2014-01-01

    To offset for the loss of managed pond habitat during restoration of wetlands to tidal marsh, the South Bay Salt Pond (SBSP) Restoration Project is enhancing some of the remaining ponds by constructing islands for roosting and nesting waterbirds. Among these wetland habitats, the SBSP Restoration Project also is installing walking trails and viewing platforms in an effort to bring the public closer to nature. In winter of 2010–11, the SBSP Restoration Project constructed 30 islands in Pond SF2 and walking trails and viewing platforms around the edge of the pond. The restoration project partners acknowledged that human disturbance could detrimentally affect nesting and roosting waterbirds. Although optimal buffer distances and potential for human disturbance were unknown, islands in Pond SF2, nevertheless, were designed with built-in buffers of greater than 300 feet (91 meters) from a trail and 600 feet (182 meters) from a viewing platform in order to minimize potential human disturbances.

  7. Beyond classic ecological assessment: The use of functional indices to indicate fish assemblages sensitivity to human disturbance in estuaries.

    Science.gov (United States)

    Teichert, Nils; Lepage, Mario; Lobry, Jérémy

    2018-05-22

    Assessing ecological health of aquatic ecosystems is crucial in the current context of biodiversity loss to guide and prioritize management actions. Although several fish-based indices were developed to assess the ecological status of estuarine ecosystems, they do not provide guidance on the causal responses of communities to disturbances. The functional trait-based approach provides an understanding of how human disturbance affects the composition of biological and ecological traits in assemblages, as well as their consequences for ecosystem functioning. Here, we evaluate the responses of fish assemblages to human disturbance in 30 French estuaries using several taxonomic and functional indices (e.g. diversity, evenness or redundancy). We tested whether these indices can provide additional information on the human impacts and health of assemblages that are not reflected by the ecological indicator (fish-based index ELFI). Results indicated that high values of local human disturbances were associated to a decrease in fish abundance, decrease in species richness and reduced functional redundancy, whereas taxonomic and functional evenness increased. In contrast, the functional richness remained stable suggesting that the functional traits of species removed by stressors were maintained by more tolerant species. Indeed, we found that the local disturbances mainly resulted in a decrease in the proportions of small benthic species feeding on macro-invertebrates, which were dominant in the studied estuaries. Some functional alterations were detected by the fish-based index, but the decline of functional redundancy was not reflected, highlighting a serious concern for management. Indeed, the abrupt collapse of functional redundancy in response to local disturbances can decrease the ability of assemblages to maintain certain species traits in the face of future environmental disturbance, including climate change. From a management perspective, the application of such

  8. Effects of human disturbance on nest placement of the woodpigeon (Columba palumbus): a case study from the Middle Atlas, Morocco.

    Science.gov (United States)

    Hanane, Saâd

    2014-06-01

    The woodpigeon (Columba palumbus) is a common and widespread bird in Morocco (North Africa). I examined, over 2 years (2010 and 2011), the breeding density and nest placement of this game species in relation to nest site habitat and degree of human disturbance. The study area was in the Middle Atlas Tighboula mountain forest, Morocco, in a disturbed and an undisturbed site. Using data collected in the 2 study sites, I aimed to identify the factors influencing the placement of nests within holm oak trees (Quercus rotundifolia) and their densities. I found that habitat structures, influenced by grazing disturbance, have affected nesting density and the location of nests of this species. Woodpigeons place their nests in a higher position (3.42 ± 0.19 m) when disturbance intensity is high and lower (1.68 ± 0.1 m) when disturbance intensity is low, and show higher nesting density in less disturbed zone (3.1 ± 0.4 nests/ha) than in highly disturbed zones (1.4 ± 0.2 nests/ha). Grazing disturbance could pose a threat to population persistence at a broader scale and could potentially reduce the abundance of this species by altering the composition and the structure of the forest nesting habitat. Further multi-scale studies are needed to assess the effects of different levels of grazing disturbance on woodpigeon nest density and placement, and to enhance our knowledge of the breeding behavior of this game species under variable environments. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  9. Do Quercus ilex woodlands undergo abrupt non-linear functional changes in response to human disturbance along a climatic gradient?

    Science.gov (United States)

    Bochet, Esther; García-Fayos, Patricio; José Molina, Maria; Moreno de las Heras, Mariano; Espigares, Tíscar; Nicolau, Jose Manuel; Monleon, Vicente

    2017-04-01

    Theoretical models predict that drylands are particularly prone to suffer critical transitions with abrupt non-linear changes in their structure and functions as a result of the existing complex interactions between climatic fluctuations and human disturbances. However, so far, few studies provide empirical data to validate these models. We aim at determining how holm oak (Quercus ilex) woodlands undergo changes in their functions in response to human disturbance along an aridity gradient (from semi-arid to sub-humid conditions), in eastern Spain. For that purpose, we used (a) remote-sensing estimations of precipitation-use-efficiency (PUE) from enhanced vegetation index (EVI) observations performed in 231x231 m plots of the Moderate Resolution Imaging Spectroradiometer (MODIS); (b) biological and chemical soil parameter determinations (extracellular soil enzyme activity, soil respiration, nutrient cycling processes) from soil sampled in the same plots; (c) vegetation parameter determinations (ratio of functional groups) from vegetation surveys performed in the same plots. We analyzed and compared the shape of the functional change (in terms of PUE and soil and vegetation parameters) in response to human disturbance intensity for our holm oak sites along the aridity gradient. Overall, our results evidenced important differences in the shape of the functional change in response to human disturbance between climatic conditions. Semi-arid areas experienced a more accelerated non-linear decrease with an increasing disturbance intensity than sub-humid ones. The proportion of functional groups (herbaceous vs. woody cover) played a relevant role in the shape of the functional response of the holm oak sites to human disturbance.

  10. Effect of human disturbance on long-term habitat use and breeding success of the European Nightjar, Caprimulgus europaeus

    Directory of Open Access Journals (Sweden)

    Andrew Lowe

    2014-12-01

    Full Text Available Land managers often respond to declining numbers of target species by creating additional areas of habitat. If these habitats are also subject to human disturbance, then their efforts may be wasted. The European Nightjar (Caprimulgus europaeus is a ground-nesting bird that is listed as a species of European Conservation Concern. It appears to be susceptible to human disturbance during the breeding season. We examined habitat use and reproductive success over 10 years in a breeding population on 1335 ha of managed land in Nottinghamshire, England. The study site was divided into a heavily disturbed section and a less disturbed section of equal habitat availability, forming a natural long-term experiment. The site is open to the public, and visitor numbers approximately doubled during the study. We found that overall Nightjar density was significantly lower and there were significantly fewer breeding pairs in the heavily disturbed habitat compared with the less disturbed habitat. However, average breeding success per pair, in terms of eggs and fledglings produced, was not significantly different between the two sections across years. Our findings suggest that human recreational disturbance may drastically alter settlement patterns and nest site selection of arriving females in some migratory ground-nesting species and may reduce the utility of apparently suitable patches of remnant and created habitat. Land managers should bear this in mind when creating new areas of habitat that will also be accessible to the public. Our study also highlights the value of long-term population monitoring, which can detect trends that short-term studies may miss.

  11. Earthworms as indicators for different forest management types and human disturbance in Ilam oak forest, Iran

    Directory of Open Access Journals (Sweden)

    Heydari Mehdi

    2014-09-01

    Full Text Available There has been observed widespread destruction of natural ecosystems around the world due to population growth, land use change and clear cutting which have affected soil properties. Different management strategies have been so far implemented to reduce this crisis in various regions of the world, such as e.g. short-term and long-term conservation management in the Zagros region. However, any management approach should be evaluated with appropriate measures to determine how managed areas respond. The main objective of the present study was to evaluate the potential of earthworms as an indicator for different forest management strategies and human disturbances in Zagros oak (Quercus persica Jaub. and Spach forest. The sites selected included undisturbed one as the control (Un, the sites under five-year conservation management (FCM and twenty-year conservation management (TCM as well as the disturbed site (D. The results of principal component analysis (PCA showed that different regions separated into the components: PC1 and PC2. Un and TCM sites gathered together and represented higher values of the factors such as pH, Kavailable, OC, clay content, Pavailable, CEC, overstory tree canopy, Ntot, biomass and abundance of earthworms. The positive direction of the first axis reflected a gradient of EC, BD and Ptot. According to the logistic model, NH4-N and EC played the most important role in earthworm presence and absence in Zagros forest ecosystem. Earthworm abundance and biomass could be a good indicator to evaluate different forest management strategies in the study area.

  12. Alternative splicing variants of human Fbx4 disturb cyclin D1 proteolysis in human cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Xiufeng; Zhang, Ting; Wang, Jie; Li, Meng; Zhang, Xiaolei; Tu, Jing [Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Sun, Shiqin [College of Pharmacy, Harbin Medical University-Daqing, Daqing, Heilongjiang 163319 (China); Chen, Xiangmei, E-mail: xm_chen6176@bjmu.edu.cn [Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Lu, Fengmin [Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China)

    2014-04-25

    Highlights: • The expression of Fbx4 was significantly lower in HCC tissues. • Novel splicing variants of Fbx4 were identified. • These novel variants are much more abundant in human cancer tissues and cells. • The novel Fbx4 isoforms could promote cell proliferation and migration in vitro. • These isoforms showed less capability for cyclin D1 binding and degradation. - Abstract: Fbx4 is a specific substrate recognition component of SCF ubiquitin ligases that catalyzes the ubiquitination and subsequent degradation of cyclin D1 and Trx1. Two isoforms of human Fbx4 protein, the full length Fbx4α and the C-terminal truncated Fbx4β have been identified, but their functions remain elusive. In this study, we demonstrated that the mRNA level of Fbx4 was significantly lower in hepatocellular carcinoma tissues than that in the corresponding non-tumor tissues. More importantly, we identified three novel splicing variants of Fbx4: Fbx4γ (missing 168–245nt of exon1), Fbx4δ (missing exon6) and a N-terminal reading frame shift variant (missing exon2). Using cloning sequencing and RT-PCR, we demonstrated these novel splice variants are much more abundant in human cancer tissues and cell lines than that in normal tissues. When expressed in Sk-Hep1 and NIH3T3 cell lines, Fbx4β, Fbx4γ and Fbx4δ could promote cell proliferation and migration in vitro. Concordantly, these isoforms could disrupt cyclin D1 degradation and therefore increase cyclin D1 expression. Moreover, unlike the full-length isoform Fbx4α that mainly exists in cytoplasm, Fbx4β, Fbx4γ, and Fbx4δ locate in both cytoplasm and nucleus. Since cyclin D1 degradation takes place in cytoplasm, the nuclear distribution of these Fbx4 isoforms may not be involved in the down-regulation of cytoplasmic cyclin D1. These results define the impact of alternative splicing on Fbx4 function, and suggest that the attenuated cyclin D1 degradation by these novel Fbx4 isoforms provides a new insight for aberrant

  13. Alternative splicing variants of human Fbx4 disturb cyclin D1 proteolysis in human cancer

    International Nuclear Information System (INIS)

    Chu, Xiufeng; Zhang, Ting; Wang, Jie; Li, Meng; Zhang, Xiaolei; Tu, Jing; Sun, Shiqin; Chen, Xiangmei; Lu, Fengmin

    2014-01-01

    Highlights: • The expression of Fbx4 was significantly lower in HCC tissues. • Novel splicing variants of Fbx4 were identified. • These novel variants are much more abundant in human cancer tissues and cells. • The novel Fbx4 isoforms could promote cell proliferation and migration in vitro. • These isoforms showed less capability for cyclin D1 binding and degradation. - Abstract: Fbx4 is a specific substrate recognition component of SCF ubiquitin ligases that catalyzes the ubiquitination and subsequent degradation of cyclin D1 and Trx1. Two isoforms of human Fbx4 protein, the full length Fbx4α and the C-terminal truncated Fbx4β have been identified, but their functions remain elusive. In this study, we demonstrated that the mRNA level of Fbx4 was significantly lower in hepatocellular carcinoma tissues than that in the corresponding non-tumor tissues. More importantly, we identified three novel splicing variants of Fbx4: Fbx4γ (missing 168–245nt of exon1), Fbx4δ (missing exon6) and a N-terminal reading frame shift variant (missing exon2). Using cloning sequencing and RT-PCR, we demonstrated these novel splice variants are much more abundant in human cancer tissues and cell lines than that in normal tissues. When expressed in Sk-Hep1 and NIH3T3 cell lines, Fbx4β, Fbx4γ and Fbx4δ could promote cell proliferation and migration in vitro. Concordantly, these isoforms could disrupt cyclin D1 degradation and therefore increase cyclin D1 expression. Moreover, unlike the full-length isoform Fbx4α that mainly exists in cytoplasm, Fbx4β, Fbx4γ, and Fbx4δ locate in both cytoplasm and nucleus. Since cyclin D1 degradation takes place in cytoplasm, the nuclear distribution of these Fbx4 isoforms may not be involved in the down-regulation of cytoplasmic cyclin D1. These results define the impact of alternative splicing on Fbx4 function, and suggest that the attenuated cyclin D1 degradation by these novel Fbx4 isoforms provides a new insight for aberrant

  14. Effect of human disturbance on the prey of tiger in the Chitwan National Park - Implications for park management

    Czech Academy of Sciences Publication Activity Database

    Bhattarai, Bishnu Prasad; Kindlmann, Pavel

    2013-01-01

    Roč. 131, DEC 15 2013 (2013), s. 343-350 ISSN 0301-4797 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk LC06073 Institutional support: RVO:67179843 Keywords : human disturbance * ungulates * conservation * habitats * predators Subject RIV: EH - Ecology, Behaviour Impact factor: 3.188, year: 2013

  15. Past Human Disturbance Effects upon Biodiversity are Greatest in the Canopy; A Case Study on Rainforest Butterflies.

    Science.gov (United States)

    Whitworth, Andrew; Villacampa, Jaime; Brown, Alice; Huarcaya, Ruthmery Pillco; Downie, Roger; MacLeod, Ross

    2016-01-01

    A key part of tropical forest spatial complexity is the vertical stratification of biodiversity, with widely differing communities found in higher rainforest strata compared to terrestrial levels. Despite this, our understanding of how human disturbance may differentially affect biodiversity across vertical strata of tropical forests has been slow to develop. For the first time, how the patterns of current biodiversity vary between three vertical strata within a single forest, subject to three different types of historic anthropogenic disturbance, was directly assessed. In total, 229 species of butterfly were detected, with a total of 5219 individual records. Butterfly species richness, species diversity, abundance and community evenness differed markedly between vertical strata. We show for the first time, for any group of rainforest biodiversity, that different vertical strata within the same rainforest, responded differently in areas with different historic human disturbance. Differences were most notable within the canopy. Regenerating forest following complete clearance had 47% lower canopy species richness than regenerating forest that was once selectively logged, while the reduction in the mid-storey was 33% and at ground level, 30%. These results also show for the first time that even long term regeneration (over the course of 30 years) may be insufficient to erase differences in biodiversity linked to different types of human disturbance. We argue, along with other studies, that ignoring the potential for more pronounced effects of disturbance on canopy fauna, could lead to the underestimation of the effects of habitat disturbance on biodiversity, and thus the overestimation of the conservation value of regenerating forests more generally.

  16. Past Human Disturbance Effects upon Biodiversity are Greatest in the Canopy; A Case Study on Rainforest Butterflies.

    Directory of Open Access Journals (Sweden)

    Andrew Whitworth

    Full Text Available A key part of tropical forest spatial complexity is the vertical stratification of biodiversity, with widely differing communities found in higher rainforest strata compared to terrestrial levels. Despite this, our understanding of how human disturbance may differentially affect biodiversity across vertical strata of tropical forests has been slow to develop. For the first time, how the patterns of current biodiversity vary between three vertical strata within a single forest, subject to three different types of historic anthropogenic disturbance, was directly assessed. In total, 229 species of butterfly were detected, with a total of 5219 individual records. Butterfly species richness, species diversity, abundance and community evenness differed markedly between vertical strata. We show for the first time, for any group of rainforest biodiversity, that different vertical strata within the same rainforest, responded differently in areas with different historic human disturbance. Differences were most notable within the canopy. Regenerating forest following complete clearance had 47% lower canopy species richness than regenerating forest that was once selectively logged, while the reduction in the mid-storey was 33% and at ground level, 30%. These results also show for the first time that even long term regeneration (over the course of 30 years may be insufficient to erase differences in biodiversity linked to different types of human disturbance. We argue, along with other studies, that ignoring the potential for more pronounced effects of disturbance on canopy fauna, could lead to the underestimation of the effects of habitat disturbance on biodiversity, and thus the overestimation of the conservation value of regenerating forests more generally.

  17. Ionospheric disturbances generated by different natural processes and by human activity in Earth plasma environment

    Directory of Open Access Journals (Sweden)

    J. Blecki

    2004-06-01

    Full Text Available The magnetosphere-ionosphere-thermosphere subsystem is strongly coupled via the electric field, particle precipitation, heat flows and small scale interaction. Satellites in situ measurements and ground based complex diagnostics can provide comprehensive coverage of both time and geomagnetic place effects. Human activity also can perturb Earth s environment, but few are connected with controlled experiments in the ionosphere and are transient. Most of them are related to industrial activity and have increased in recent years. The most important power sources are broadcasting transmitters, power stations, power lines and heavy industry. At ionospheric altitude some disturbances and physical processes are related to seismic activity, thunderstorm activity and some global changes in the Earth environment such as ozone holes. Various natural and artificial indicators can affect satellite telecommunication quality. The aim of this presentation is to report progress in understanding the physical processes in the ionosphere described above and to assess the application of these considerations to the study of plasma effects on Earth-space and satellite-to-satellite communication.

  18. Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps

    Directory of Open Access Journals (Sweden)

    Zhao Biqiang

    2007-07-01

    Full Text Available Using 8-year global ionosphere maps (GIMs of TEC products from the Jet Propulsion Laboratory (JPL, we make a statistical study on the morphology of the global ionospheric behaviors with respect to the geomagnetic disturbances. Results show that the behaviors of TEC during geomagnetic storm present clear seasonal and local time variations under geomagnetic control in a similar way as those of NmF2 (Field and Rishbeth, 1997. A negative phase of TEC occurs with high probability in the summer hemisphere and most prominent near the geomagnetic poles, while a positive phase is obvious in the winter hemisphere and in the far pole region. A negative storm effect toward lower latitudes tends to occur from post-midnight to the morning sector and recedes to high latitude in the afternoon. A positive storm effect is separated by geomagnetic latitudes and magnetic local time. Furthermore, ionospheric responses at different local time sectors with respect to the storm commencement shows very different developing processes corresponding to the evolution of the geomagnetic storm. A daytime positive storm effect is shown to be more prominent in the American region than those in the Asian and European regions, which may suggest a longitudinal effect of the ionospheric storm.

  19. Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps

    Directory of Open Access Journals (Sweden)

    Z. Biqiang

    2007-07-01

    Full Text Available Using 8-year global ionosphere maps (GIMs of TEC products from the Jet Propulsion Laboratory (JPL, we make a statistical study on the morphology of the global ionospheric behaviors with respect to the geomagnetic disturbances. Results show that the behaviors of TEC during geomagnetic storm present clear seasonal and local time variations under geomagnetic control in a similar way as those of NmF2 (Field and Rishbeth, 1997. A negative phase of TEC occurs with high probability in the summer hemisphere and most prominent near the geomagnetic poles, while a positive phase is obvious in the winter hemisphere and in the far pole region. A negative storm effect toward lower latitudes tends to occur from post-midnight to the morning sector and recedes to high latitude in the afternoon. A positive storm effect is separated by geomagnetic latitudes and magnetic local time. Furthermore, ionospheric responses at different local time sectors with respect to the storm commencement shows very different developing processes corresponding to the evolution of the geomagnetic storm. A daytime positive storm effect is shown to be more prominent in the American region than those in the Asian and European regions, which may suggest a longitudinal effect of the ionospheric storm.

  20. The effects of human disturbance on the activity of wild reindeer in different physical condition

    Directory of Open Access Journals (Sweden)

    Terje Skogland

    1988-06-01

    Full Text Available We compared two Norwegian wild reindeer herds, Knutsho in excellent physical condition and Hardangervidda in poor physical condition, before and during disturbance by human hunters in order to test whether physical condition effected foraging strategy under stress. Both herds were being regularly hunted (man had been a natural predator on reindeer since prehistoric time. The well-fed Knutsho animals were ca. 30% larger at the start of the hunting season in late August. Before exposure they foraged less and walked more, i.e. were more selective than the Hardangervidda animals which were in energetically lower condition and foraged significantly more and spent less time moving between habitat patches and less time standing. After exposure to hunters disturbed Knutsho animals aggregated into significantly larger groups than before hunting and stood alert more, while Hardangervidda animals spent the same minimum amount of time foraging but moved significantly more and spent almost no time standing. The frequency of disturbance was not significantly different between the two herds and their speeds of movement after disturbances were similar. The hunter kill success rate was also similar in the two areas. The energetic costs, measured as relative body weight loss during the hunting season, was higher for the initially less well-fed Hardangervidda animals, and higher for both herds compared to that from a less disturbed herd (Forelhogna. We hypothezise that while standing still and alert in aggregated groups is risky, it is still more risky to move, but potentially more rewarding if a better habitat could be found. More well-fed Knutsho animals, which aggregated and stood still, conserved allready stored energy, compatible with a time minimizer risk aversive strategy. The Hardangervidda animals which were in poorer condition increased travelling time to an extent that suggested a risky nutrient miximizer strategy in the phase of stress.Effekter av

  1. Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker.

    Science.gov (United States)

    Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E; Whitley, Guy; Johnsen, Guro M; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C; Müller, Dominik N; Staff, Anne Cathrine; Hurst, Laurence D; Dechend, Ralf; Izsvák, Zsuzsanna

    2017-11-07

    Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5 , with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5 high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in

  2. Human disturbance provides foraging opportunities for birds in primary subalpine forest

    DEFF Research Database (Denmark)

    DuBay, Shane G.; Hart Reeve, Andrew; Wu, Yongjie

    2017-01-01

    or Cettia major, and Heteroxenicus stellatus. This behavior is likely a modification of pre-existing interspecific foraging associations with pheasants and large mammals in the region. These larger animals disturb the earth and lower vegetation layers upon passage and while foraging, exposing previously...... opportunities. We cut and cleared small swaths of dense bamboo growth for an unrelated study. Multiple insectivorous species were recruited to the cleared areas, foraging extensively in the disturbed earth, often within 1 m of us. These species included Tarsiger chrysaeus, Tarsiger indicus, Cettia brunnifrons...

  3. Disturbance in boreal forest ecosystems: human impacts and natural processes. Proceedings of the International Boreal Forest Research Association 1997 annual meeting; 1997 August 4-7; Duluth, Minnesota.

    Science.gov (United States)

    2000-01-01

    The papers in these proceedings cover a wide range of topics related to human and natural disturbance processes in forests of the boreal zone in North America and Eurasia. Topics include historic and predicted landscape change; forest management; disturbance by insects, fire, air pollution, severe weather, and global climate change; and carbon cycling.

  4. Disturbing forest disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Volney, W.J.A.; Hirsch, K.G. [Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, AB (Canada)

    2005-10-01

    This paper described the role that disturbances play in maintaining the ecological integrity of Canadian boreal forests. Potential adaptation options to address the challenges that these disturbances present were also examined. Many forest ecosystems need fire for regeneration, while other forests rely on a cool, wet disintegration process driven by insects and commensal fungi feeding on trees to effect renewal. While there are characteristic natural, temporal and spatial patterns to these disturbances, recent work has demonstrated that the disturbances are being perturbed by climatic change that has been compounded by anthropogenic disturbances in forests. Fire influences species composition and age structure, regulates forest insects and diseases, affects nutrient cycling and energy fluxes, and maintains the productivity of different habitats. Longer fire seasons as a result of climatic change will lead to higher intensity fires that may more easily evade initial attacks and become problematic. Fire regimes elevated beyond the range of natural variation will have a dramatic effect on the regional distribution and functioning of forest ecosystems and pose a threat to the safety and prosperity of people. While it was acknowledged that if insect outbreaks were to be controlled on the entire forest estate, the productivity represented by dead wood would be lost, it was suggested that insects such as the forest tent caterpillar and the spruce bud worm may also pose a greater threat as the climate gets warmer and drier. Together with fungal associates, saproxylic arthropods are active in nutrient cycling and ultimately determine the fertility of forest sites. It was suggested that the production of an age class structure and forest mosaic would render the forest landscape less vulnerable to the more negative aspects of climate change on vegetation response. It was concluded that novel management design paradigms are needed to successfully reduce the risk from threats

  5. Electronic human resource management: Enhancing or entrancing?

    Directory of Open Access Journals (Sweden)

    Paul Poisat

    2017-07-01

    Full Text Available Orientation: This article provides an investigation into the current level of development of the body of knowledge related to electronic human resource management (e-HRM by means of a qualitative content analysis. Several aspects of e-HRM, namely definitions of e-HRM, the theoretical perspectives around e-HRM, the role of e-HRM, the various types of e-HRM and the requirements for successful e-HRM, are examined. Research purpose: The purpose of the article was to determine the status of e-HRM and examine the studies that report on the link between e-HRM and organisational productivity. Motivation for the study: e-HRM has the capacity to improve organisational efficiency and leverage the role of human resources (HR as a strategic business partner. Main findings: The notion that the implementation of e-HRM will lead to improved organisational productivity is commonly assumed; however, empirical evidence in this regard was found to be limited. Practical/managerial implications: From the results of this investigation it is evident that more research is required to gain a greater understanding of the influence of e-HRM on organisational productivity, as well as to develop measures for assessing this influence. Contribution: This article proposes additional areas to research and measure when investigating the effectiveness of e-HRM. It provides a different lens from which to view e-HRM assessment whilst keeping it within recognised HR measurement parameters (the HR value chain. In addition, it not only provides areas for measuring e-HRM’s influence but also provides important clues as to how the measurements may be approached.

  6. Electron tomography study of isolated human centrioles.

    Science.gov (United States)

    Ibrahim, Rana; Messaoudi, Cédric; Chichon, Francisco Javier; Celati, Claude; Marco, Sergio

    2009-01-01

    Centrioles are components of the centrosome, which is present in most eukaryotic cells (from protozoa to mammals). They organize the microtubule skeleton during interphase and the mitotic spindle during cell division. In ciliate cells, centrioles form basal bodies that are involved in cellular motility. Despite their important roles in biology, the detailed structure of centrioles remains obscure. This work contributes to a more complete model of centriole structure. The authors used electron tomography of isolated centrosomes from the human lymphoblast KE37 to explore the details of subdistal appendages and centriole lumen organization in mother centrioles. Their results reveal that each of the nine subdistal appendages is composed of two halves (20 nm diameter each) fused in a 40 nm tip that extends 100 nm from where it anchors to microtubules. The centriole lumen is filled at the distal domain by a 45 nm periodic stack of rings. Each ring has a 30 nm diameter, is 15 nm thick, and appears to be tilted at 53 degrees perpendicular to the centriole axis. The rings are anchored to microtubules by arms. Based on their results, the authors propose a model of the mother centriole distal structure. Copyright 2008 Wiley-Liss, Inc.

  7. Human-Derived Disturbance Estimation and Compensation (DEC) Method Lends Itself to a Modular Sensorimotor Control in a Humanoid Robot.

    Science.gov (United States)

    Lippi, Vittorio; Mergner, Thomas

    2017-01-01

    The high complexity of the human posture and movement control system represents challenges for diagnosis, therapy, and rehabilitation of neurological patients. We envisage that engineering-inspired, model-based approaches will help to deal with the high complexity of the human posture control system. Since the methods of system identification and parameter estimation are limited to systems with only a few DoF, our laboratory proposes a heuristic approach that step-by-step increases complexity when creating a hypothetical human-derived control systems in humanoid robots. This system is then compared with the human control in the same test bed, a posture control laboratory. The human-derived control builds upon the identified disturbance estimation and compensation (DEC) mechanism, whose main principle is to support execution of commanded poses or movements by compensating for external or self-produced disturbances such as gravity effects. In previous robotic implementation, up to 3 interconnected DEC control modules were used in modular control architectures separately for the sagittal plane or the frontal body plane and successfully passed balancing and movement tests. In this study we hypothesized that conflict-free movement coordination between the robot's sagittal and frontal body planes emerges simply from the physical embodiment, not necessarily requiring a full body control. Experiments were performed in the 14 DoF robot Lucy Posturob (i) demonstrating that the mechanical coupling from the robot's body suffices to coordinate the controls in the two planes when the robot produces movements and balancing responses in the intermediate plane, (ii) providing quantitative characterization of the interaction dynamics between body planes including frequency response functions (FRFs), as they are used in human postural control analysis, and (iii) witnessing postural and control stability when all DoFs are challenged together with the emergence of inter

  8. Comparative sensitivity to environmental variation and human disturbance of Asian tapirs (Tapirus indicus) and other wild ungulates in Thailand.

    Science.gov (United States)

    Lynam, Antony J; Tantipisanuh, Naruemon; Chutipong, Wanlop; Ngoprasert, Dusit; Baker, Megan C; Cutter, Passanan; Gale, George; Kitamura, Shumpei; Steinmetz, Robert; Sukmasuang, Ronglarp; Thunhikorn, Somying

    2012-12-01

    Southeast Asia's tropical forests suffer the highest rates of deforestation and disturbance of any on Earth, with poorly understood impacts on native fauna. Asian tapirs (Tapirus indicus) are among the least studied of the large mammals in these forests. Using records from 9 camera trap surveys in 7 of the largest (>1000 km(2) ) protected area complexes, we assessed the influence of environmental variation and human-induced disturbance on tapir occurrence. Tapirs were detected at 13% of locations sampled, significantly associated with evergreen forest (P tapir presence 87% of the time. According to this model, tapir occurrence was positively influenced by annual rainfall and proximity to the forest edge. However, tapirs may not avoid edges but instead prefer wetter evergreen forest, a habitat type that tended to occur further from the forest edge at higher elevations in our particular study sites (P tapirs showed a range of differing responses. Tapirs are expected to be less sensitive to disturbance because they are not targets for hunting and trade, and are almost entirely active at night, so avoid peak traffic periods in parks. Tapir populations in Thailand may be more stable than in other parts of their global range because rates of forest loss have decreased >40% over the past 20 years. We recommend surveys to fill gaps in the understanding of the status in lesser-known protected areas, research to better understand the fine-scale environmental influences on behavior and habitats of tapirs, and other forest ungulates, and continued legal status for tapirs in the highest category of protection. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  9. Flight initiation distances of nesting Piping Plovers (Charadrius melodus in response to human disturbance

    Directory of Open Access Journals (Sweden)

    Joel G. Jorgensen

    2016-06-01

    Full Text Available Birds frequently interact with people when they occur in coupled human-ecological or anthropogenic environments, which makes the protection of legally protected species a challenge. Flight initiation distances (FIDs are often used to inform development of appropriate buffer distances required for human exclusion zones used to protect birds nesting in anthropogenic landscapes. Piping Plovers (Charadrius melodus are protected by the Endangered Species Act in the United States and often nest in areas used by humans. Studies evaluating Piping Plover FIDs are limited and implementation of exclusion zones has been inconsistent across the species' range. We measured Piping Plover response and FIDs to naturally occurring stimuli on public beaches at Lake McConaughy, Nebraska, USA. Piping Plover FIDs differed most by stimulus class (vehicle, human, dog, human with dog, Julian day, and hour of day. Piping Plover FIDs were greatest for dog and human with dog compared to humans and vehicles. For all types of stimuli, Piping Plover FIDs decreased over time during the nesting season and increased slightly during each day. In the majority of instances in which Piping Plovers left their nests, return times to the nest were relatively short (less than three minutes. These results suggest Piping Plovers become habituated to the presence of human-related stimuli over the course of a nesting season, but other explanations such as parental investment and risk allocation cannot be excluded. Additional research and improved guidance regarding the implementation of exclusion zones is needed so managers can implement effective protection programs in anthropogenic landscapes.

  10. Paracetamol-induced spindle disturbances in V79 cells with and without expression of human CYP1A2

    DEFF Research Database (Denmark)

    Jensen, K G; Poulsen, H E; Doehmer, J

    1996-01-01

    Spindle disturbing effects in terms of c-mitosis and cytotoxicity of paracetamol were investigated in two Chinese hamster V79 cell lines, one of which (V79MZh1A2) was transfected with human CYP1A2. This enzyme catalyses the oxidative formation of the reactive paracetamol metabolite, NAPQI, believed...... to initiate hepatoxicity by covalent binding to proteins after overdose. In the native V79 cell line paracetamol increased c-mitosis frequency in a concentration dependent manner from 8.7 + or - 3.5% (control) to 66 + or - 18% at 20 mM. A significant increase to 13.3 + or - 3.5% was first seen at 2.5 m......M in the native cell line (Pparacetamol. At 5 mM paracetamol the c-mitosis frequency was 14.4 + or - 5.0% and 19.0 + or - 3...

  11. Differential flight responses of spring staging Teal Anas crecca and Wigeon A. penelope to human vs. natural disturbance

    DEFF Research Database (Denmark)

    Bregnballe, Thomas; Speich, Charlotte; Horsten, Anders

    2017-01-01

    (anglers, cyclists, farming activity) on the flight responses and displacement distances of ducks within uniform habitat along a public path were compared with the birds’ reaction to natural stimuli such as mammals or birds of prey. Excluding the controlled disturbance by a pedestrian, undertaken as part...... of the study, the main cause of flushing in Wigeon was a response to the movements of birds of prey and other birds, especially Lapwings Vanellus vanellus performing flight displays. For Teal, birds of prey accounted for around half of the flushes, with other birds accounting for one third of the flushes....... Wigeon and Teal were displaced significantly farther by human activities than by natural causes. We tested whether the ducks reacted differently to natural disturbances shortly after disturbance by a pedestrian by comparing response patterns to natural stimuli within the first hour following disturbance...

  12. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  13. Assessment of ecological and human health risks of heavy metal contamination in agriculture soils disturbed by pipeline construction.

    Science.gov (United States)

    Shi, Peng; Xiao, Jun; Wang, Yafeng; Chen, Liding

    2014-02-28

    The construction of large-scale infrastructures such as nature gas/oil pipelines involves extensive disturbance to regional ecosystems. Few studies have documented the soil degradation and heavy metal contamination caused by pipeline construction. In this study, chromium (Cr), cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) levels were evaluated using Index of Geo-accumulation (Igeo) and Potential Ecological Risk Index (RI) values, and human health risk assessments were used to elucidate the level and spatial variation of heavy metal pollution risks. The results showed that the impact zone of pipeline installation on soil heavy metal contamination was restricted to pipeline right-of-way (RoW), which had higher Igeo of Cd, Cu, Ni and Pb than that of 20 m and 50 m. RI showed a declining tendency in different zones as follows: trench > working zone > piling area > 20 m > 50 m. Pipeline RoW resulted in higher human health risks than that of 20 m and 50 m, and children were more susceptible to non-carcinogenic hazard risk. Cluster analysis showed that Cu, Ni, Pb and Cd had similar sources, drawing attention to the anthropogenic activity. The findings in this study should help better understand the type, degree, scope and sources of heavy metal pollution from pipeline construction to reduce pollutant emissions, and are helpful in providing a scientific basis for future risk management.

  14. Disturbed α-Cell Function in Mice with β-Cell Specific Overexpression of Human Islet Amyloid Polypeptide

    Directory of Open Access Journals (Sweden)

    Bo Ahrén

    2008-01-01

    Full Text Available Exogenous administration of islet amyloid polypeptide (IAPP has been shown to inhibit both insulin and glucagon secretion. This study examined α-cell function in mice with β-cell specific overexpression of human IAPP (hIAPP after an oral protein gavage (75 mg whey protein/mouse. Baseline glucagon levels were higher in transgenic mice (41±4.0 pg/mL, n=6 than in wildtype animals (19±5.1 pg/mL, n=5, P=.015. In contrast, the glucagon response to protein was impaired in transgenic animals (21±2.7 pg/mL in transgenic mice versus 38±5.7 pg/mL in wildtype mice at 15 minutes; P=.027. Baseline insulin levels did not differ between the groups, while the insulin response, as the glucagon response, was impaired after protein challenge (P=.018. Glucose levels were not different between the groups and did not change significantly after protein gavage. Acetaminophen was given through gavage to the animals (2 mg/mouse to estimate gastric emptying. The plasma acetaminophen profile was similar in the two groups of mice. We conclude that disturbances in glucagon secretion exist in mice with β-cell specific overexpression of human IAPP, which are not secondary to changes in gastric emptying. The reduced glucagon response to protein challenge may reflect a direct inhibitory influence of hIAPP on glucagon secretion.

  15. Assessment of Ecological and Human Health Risks of Heavy Metal Contamination in Agriculture Soils Disturbed by Pipeline Construction

    Directory of Open Access Journals (Sweden)

    Peng Shi

    2014-02-01

    Full Text Available The construction of large-scale infrastructures such as nature gas/oil pipelines involves extensive disturbance to regional ecosystems. Few studies have documented the soil degradation and heavy metal contamination caused by pipeline construction. In this study, chromium (Cr, cadmium (Cd, copper (Cu, nickel (Ni, lead (Pb and zinc (Zn levels were evaluated using Index of Geo-accumulation (Igeo and Potential Ecological Risk Index (RI values, and human health risk assessments were used to elucidate the level and spatial variation of heavy metal pollution risks. The results showed that the impact zone of pipeline installation on soil heavy metal contamination was restricted to pipeline right-of-way (RoW, which had higher Igeo of Cd, Cu, Ni and Pb than that of 20 m and 50 m. RI showed a declining tendency in different zones as follows: trench > working zone > piling area > 20 m > 50 m. Pipeline RoW resulted in higher human health risks than that of 20 m and 50 m, and children were more susceptible to non-carcinogenic hazard risk. Cluster analysis showed that Cu, Ni, Pb and Cd had similar sources, drawing attention to the anthropogenic activity. The findings in this study should help better understand the type, degree, scope and sources of heavy metal pollution from pipeline construction to reduce pollutant emissions, and are helpful in providing a scientific basis for future risk management.

  16. Practical guide to electronic resources in the humanities

    CERN Document Server

    Dubnjakovic, Ana

    2010-01-01

    From full-text article databases to digitized collections of primary source materials, newly emerging electronic resources have radically impacted how research in the humanities is conducted and discovered. This book, covering high-quality, up-to-date electronic resources for the humanities, is an easy-to-use annotated guide for the librarian, student, and scholar alike. It covers online databases, indexes, archives, and many other critical tools in key humanities disciplines including philosophy, religion, languages and literature, and performing and visual arts. Succinct overviews of key eme

  17. Human disturbance and upward expansion of plants in a warming climate

    Science.gov (United States)

    Dainese, Matteo; Aikio, Sami; Hulme, Philip E.; Bertolli, Alessio; Prosser, Filippo; Marini, Lorenzo

    2017-08-01

    Climate change is expected to trigger an upward expansion of plants in mountain regions and, although there is strong evidence that many native species have already shifted their distributions to higher elevations, little is known regarding how fast non-native species might respond to climate change. By analysing 131,394 occurrence records of 1,334 plant species collected over 20 years in the European Alps, we found that non-natives are spreading upwards approximately twice as fast as natives. Whereas the spread of natives was enhanced by traits favouring longer dispersal distances, this was not the case for non-natives. This was due to the non-native species pool already being strongly biased towards species that had traits facilitating spread. A large proportion of native and non-native species seemed to be able to spread upwards faster than the current velocity of climate change. In particular, long-distance dispersal events and proximity to roads proved to be key drivers for the observed rapid spread. Our findings highlight that invasions by non-native species into native alpine communities are a potentially significant additional pressure on these vulnerable ecosystems that are already likely to suffer dramatic vegetation changes with ongoing warming and increasing human activity in mountain regions.

  18. Effect of human disturbance on seed and seedling distribution of the Andean Oak (Quercus humboldtii Bonpl., Fagaceae) in the Colombian Eastern Cordillera

    International Nuclear Information System (INIS)

    Guerrero Rodriguez, Sandra Bibiana; Paz Camacho, Erika Andrea; Parrado Rosselli, Angela

    2010-01-01

    Animals affect the spatial occupation patterns of tropical forest plants throughout the seed dispersal they perform. Therefore, changes in vertebrate populations by human disturbance might affect re generation dynamics of plant species. We studied differences in the spatial distribution of seeds and seedlings of the Andean oak (Quercus humboldtii) between two nearby forests with contrasting levels of anthropogenic influence in the Colombian Andes. Density and spatial distribution of seedlings were evaluated in 490 and 484 1 m2 plots located in a 28 ha area, in the high and low disturbed site, respectively. In each plot, all seedlings found were sampled and classified into three age categories. Density and spatial distribution of seeds were evaluated in 0.25 m 2s ubplots placed in the same plots described above. Results showed a higher number and density of seedlings in the high disturbed site, as well as a marked decrease in seedling density as age increases. Distances to the nearest neighbour were shorter in the high disturbed site for all seedlings and each age category, in contrast to the low disturbed site. Indexes of spatial distribution indicate an aggregated pattern in the most disturbed site, while a uniform pattern in the low disturbed one. Seeds also exhibited an aggregated pattern in the high disturbed site and a higher seed predation by invertebrates. Results seemed to be a consequence of forest fragmentation and a decrease of vertebrate seed dispersers, seed predators and herbivores associated to the regeneration processes of the species. These results provide important information for the forest management and restoration activities, since in order to maintain plant populations in the long term, presence and viable populations of seed dispersers should be also maintained.

  19. Developing Humanities Collections in the Digital Age: Exploring Humanities Faculty Engagement with Electronic and Print Resources

    Science.gov (United States)

    Kachaluba, Sarah Buck; Brady, Jessica Evans; Critten, Jessica

    2014-01-01

    This article is based on quantitative and qualitative research examining humanities scholars' understandings of the advantages and disadvantages of print versus electronic information resources. It explores how humanities' faculty members at Florida State University (FSU) use print and electronic resources, as well as how they perceive these…

  20. Evidences that human disturbance simplify the ant fauna associated a Stachytarpheta glabra Cham. (Verbenaceae compromising the benefits of ant-plant mutualism

    Directory of Open Access Journals (Sweden)

    BC. Barbosa

    Full Text Available Interaction among species, like ants and plants through extrafloral nectaries (EFNs, are important components of ecological communities’ evolution. However, the effect of human disturbance on such specific interactions and its ecological consequences is poorly understood. This study evaluated the outcomes of mutualism between ants and the EFN-bearing plant Stachytarpheta glabra under anthropogenic disturbance. We compared the arthropod fauna composition between two groups of twenty plant individuals, one in an area disturbed by human activities and one in a preserved area. We also check the plant investment in herbivory defense and the consequential leaf damage by herbivore. Our results indicate that such disturbances cause simplification of the associated fauna and lack of proper ant mutualist. This led to four times more herbivory on plants of disturbed areas, despite the equal amount of EFN and ant visitors and low abundance of herbivores. The high pressure of herbivory may difficult the re-establishment of S. glabra, an important pioneer species in ferruginous fields, therefore it may affect resilience of this fragile ecological community.

  1. Leptospira interrogans causes quantitative and morphological disturbances in adherens junctions and other biological groups of proteins in human endothelial cells.

    Science.gov (United States)

    Sato, Hiromi; Coburn, Jenifer

    2017-07-01

    Pathogenic Leptospira transmits from animals to humans, causing the zoonotic life-threatening infection called leptospirosis. This infection is reported worldwide with higher risk in tropical regions. Symptoms of leptospirosis range from mild illness to severe illness such as liver damage, kidney failure, respiratory distress, meningitis, and fatal hemorrhagic disease. Invasive species of Leptospira rapidly disseminate to multiple tissues where this bacterium damages host endothelial cells, increasing vascular permeability. Despite the burden in humans and animals, the pathogenic mechanisms of Leptospira infection remain to be elucidated. The pathogenic leptospires adhere to endothelial cells and permeabilize endothelial barriers in vivo and in vitro. In this study, human endothelial cells were infected with the pathogenic L. interrogans serovar Copenhageni or the saprophyte L. biflexa serovar Patoc to investigate morphological changes and other distinctive phenotypes of host cell proteins by fluorescence microscopy. Among those analyzed, 17 proteins from five biological classes demonstrated distinctive phenotypes in morphology and/or signal intensity upon infection with Leptospira. The affected biological groups include: 1) extracellular matrix, 2) intercellular adhesion molecules and cell surface receptors, 3) intracellular proteins, 4) cell-cell junction proteins, and 5) a cytoskeletal protein. Infection with the pathogenic strain most profoundly disturbed the biological structures of adherens junctions (VE-cadherin and catenins) and actin filaments. Our data illuminate morphological disruptions and reduced signals of cell-cell junction proteins and filamentous actin in L. interrogans-infected endothelial cells. In addition, Leptospira infection, regardless of pathogenic status, influenced other host proteins belonging to multiple biological classes. Our data suggest that this zoonotic agent may damage endothelial cells via multiple cascades or pathways

  2. Leptospira interrogans causes quantitative and morphological disturbances in adherens junctions and other biological groups of proteins in human endothelial cells.

    Directory of Open Access Journals (Sweden)

    Hiromi Sato

    2017-07-01

    Full Text Available Pathogenic Leptospira transmits from animals to humans, causing the zoonotic life-threatening infection called leptospirosis. This infection is reported worldwide with higher risk in tropical regions. Symptoms of leptospirosis range from mild illness to severe illness such as liver damage, kidney failure, respiratory distress, meningitis, and fatal hemorrhagic disease. Invasive species of Leptospira rapidly disseminate to multiple tissues where this bacterium damages host endothelial cells, increasing vascular permeability. Despite the burden in humans and animals, the pathogenic mechanisms of Leptospira infection remain to be elucidated. The pathogenic leptospires adhere to endothelial cells and permeabilize endothelial barriers in vivo and in vitro. In this study, human endothelial cells were infected with the pathogenic L. interrogans serovar Copenhageni or the saprophyte L. biflexa serovar Patoc to investigate morphological changes and other distinctive phenotypes of host cell proteins by fluorescence microscopy. Among those analyzed, 17 proteins from five biological classes demonstrated distinctive phenotypes in morphology and/or signal intensity upon infection with Leptospira. The affected biological groups include: 1 extracellular matrix, 2 intercellular adhesion molecules and cell surface receptors, 3 intracellular proteins, 4 cell-cell junction proteins, and 5 a cytoskeletal protein. Infection with the pathogenic strain most profoundly disturbed the biological structures of adherens junctions (VE-cadherin and catenins and actin filaments. Our data illuminate morphological disruptions and reduced signals of cell-cell junction proteins and filamentous actin in L. interrogans-infected endothelial cells. In addition, Leptospira infection, regardless of pathogenic status, influenced other host proteins belonging to multiple biological classes. Our data suggest that this zoonotic agent may damage endothelial cells via multiple cascades or

  3. Leptospira interrogans causes quantitative and morphological disturbances in adherens junctions and other biological groups of proteins in human endothelial cells

    Science.gov (United States)

    Sato, Hiromi

    2017-01-01

    Pathogenic Leptospira transmits from animals to humans, causing the zoonotic life-threatening infection called leptospirosis. This infection is reported worldwide with higher risk in tropical regions. Symptoms of leptospirosis range from mild illness to severe illness such as liver damage, kidney failure, respiratory distress, meningitis, and fatal hemorrhagic disease. Invasive species of Leptospira rapidly disseminate to multiple tissues where this bacterium damages host endothelial cells, increasing vascular permeability. Despite the burden in humans and animals, the pathogenic mechanisms of Leptospira infection remain to be elucidated. The pathogenic leptospires adhere to endothelial cells and permeabilize endothelial barriers in vivo and in vitro. In this study, human endothelial cells were infected with the pathogenic L. interrogans serovar Copenhageni or the saprophyte L. biflexa serovar Patoc to investigate morphological changes and other distinctive phenotypes of host cell proteins by fluorescence microscopy. Among those analyzed, 17 proteins from five biological classes demonstrated distinctive phenotypes in morphology and/or signal intensity upon infection with Leptospira. The affected biological groups include: 1) extracellular matrix, 2) intercellular adhesion molecules and cell surface receptors, 3) intracellular proteins, 4) cell-cell junction proteins, and 5) a cytoskeletal protein. Infection with the pathogenic strain most profoundly disturbed the biological structures of adherens junctions (VE-cadherin and catenins) and actin filaments. Our data illuminate morphological disruptions and reduced signals of cell-cell junction proteins and filamentous actin in L. interrogans-infected endothelial cells. In addition, Leptospira infection, regardless of pathogenic status, influenced other host proteins belonging to multiple biological classes. Our data suggest that this zoonotic agent may damage endothelial cells via multiple cascades or pathways

  4. Distribution of a Community of Mammals in Relation to Roads and Other Human Disturbances in Gabon, Central Africa

    Science.gov (United States)

    Vanthomme, Hadrien; Kolowski, Joseph; Korte, Lisa; Alonso, Alfonso

    2013-01-01

    Abstract We present the first community-level study of the associations of both roads and other human disturbances with the distribution of mammals in Gabon (central Africa). Our study site was in an oil concession within a littoral mosaic landscape. We conducted surveys along 199 line transects and installed camera traps on 99 of these transects to document mammal presence and abundance. We used generalized linear mixed-effect models to document associations between variables related to the ecosystem (land cover, topography, and hydrology), roads (coating, width of rights of way, condition, type of vehicle used on the road, traffic level, affiliation of users, and general type of road), and other human disturbances (urbanization, agriculture, hunting, logging, gathering, and industrial activities) and the abundance or presence of 17 species or groups of mammals including elephant (Loxodonta cyclotis), buffalo (Syncerus caffer), sitatunga (Tragelaphus spekei), red river hog (Potamochoerus porcus), smaller ungulates, gorilla (Gorilla gorilla), chimpanzee (Pan troglodytes), side-striped jackal (Canis adustus), carnivores, monkeys, and large rodents. Some types of roads and other human disturbances were negatively associated with the abundance or presence of elephants, buffalos, gorillas, sitatungas, some monkeys, and duikers. The pattern of associations of mammals with roads and other human disturbances was diverse and included positive associations with road presence (red river hog, some monkeys, and duikers), agriculture (sitatunga, small carnivores, and large rodents) and industrial activities (sitatunga, red river hog, red duikers, and side-striped jackal). Our results suggest that the community of mammals we studied was mostly affected by hunting, agriculture, and urbanization, which are facilitated by road presence. We recommend increased regulation of agriculture, hunting, and road building in the area. Distribución de una Comunidad de Mamíferos en Relaci

  5. Disturbed neuronal ER-Golgi sorting of unassembled glycine receptors suggests altered subcellular processing is a cause of human hyperekplexia.

    Science.gov (United States)

    Schaefer, Natascha; Kluck, Christoph J; Price, Kerry L; Meiselbach, Heike; Vornberger, Nadine; Schwarzinger, Stephan; Hartmann, Stephanie; Langlhofer, Georg; Schulz, Solveig; Schlegel, Nadja; Brockmann, Knut; Lynch, Bryan; Becker, Cord-Michael; Lummis, Sarah C R; Villmann, Carmen

    2015-01-07

    Recent studies on the pathogenic mechanisms of recessive hyperekplexia indicate disturbances in glycine receptor (GlyR) α1 biogenesis. Here, we examine the properties of a range of novel glycine receptor mutants identified in human hyperekplexia patients using expression in transfected cell lines and primary neurons. All of the novel mutants localized in the large extracellular domain of the GlyR α1 have reduced cell surface expression with a high proportion of receptors being retained in the ER, although there is forward trafficking of glycosylated subpopulations into the ER-Golgi intermediate compartment and cis-Golgi compartment. CD spectroscopy revealed that the mutant receptors have proportions of secondary structural elements similar to wild-type receptors. Two mutants in loop B (G160R, T162M) were functional, but none of those in loop D/β2-3 were. One nonfunctional truncated mutant (R316X) could be rescued by coexpression with the lacking C-terminal domain. We conclude that a proportion of GlyR α1 mutants can be transported to the plasma membrane but do not necessarily form functional ion channels. We suggest that loop D/β2-3 is an important determinant for GlyR trafficking and functionality, whereas alterations to loop B alter agonist potencies, indicating that residues here are critical elements in ligand binding. Copyright © 2015 the authors 0270-6474/15/350422-16$15.00/0.

  6. Inhibition of α-adrenergic tone disturbs the distribution of blood flow in the exercising human limb.

    Science.gov (United States)

    Heinonen, Ilkka; Wendelin-Saarenhovi, Maria; Kaskinoro, Kimmo; Knuuti, Juhani; Scheinin, Mika; Kalliokoski, Kari K

    2013-07-15

    The role of neuronal regulation of human cardiovascular function remains incompletely elucidated, especially during exercise. Here we, by positron emission tomography, monitored tissue-specific blood flow (BF) changes in nine healthy young men during femoral arterial infusions of norepinephrine (NE) and phentolamine. At rest, the α-adrenoceptor agonist NE reduced BF by ~40%, similarly in muscles (from 3.2 ± 1.9 to 1.4 ± 0.3 ml·min(-1)·100 g(-1) in quadriceps femoris muscle), bone (from 1.1 ± 0.4 to 0.5 ± 0.2 ml·min(-1)·100 g(-1)) and adipose tissue (AT) (from 1.2 ± 0.7 to 0.7 ± 0.3 ml·min(-1)·100 g(-1)). During exercise, NE reduced exercising muscle BF by ~16%. BF in AT was reduced similarly as rest. The α-adrenoceptor antagonist phentolamine increased BF similarly in the different muscles and other tissues of the limb at rest. During exercise, BF in inactive muscle was increased 3.4-fold by phentolamine compared with exercise without drug, but BF in exercising muscles was not influenced. Bone and AT (P = 0.055) BF were also increased by phentolamine in the exercise condition. NE increased and phentolamine decreased oxygen extraction in the limb during exercise. We conclude that inhibition of α-adrenergic tone markedly disturbs the distribution of BF and oxygen extraction in the exercising human limb by increasing BF especially around inactive muscle fibers. Moreover, although marked functional sympatholysis also occurs during exercise, the arterial NE infusion that mimics the exaggerated sympathetic nerve activity commonly seen in patients with cardiovascular disease was still capable of directly limiting BF in the exercising leg muscles.

  7. Human disturbances, habitat characteristics and social environment generate sex-specific responses in vigilance of Mediterranean mouflon.

    Directory of Open Access Journals (Sweden)

    Stéphanie Benoist

    Full Text Available In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp. in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%, not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8% whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of

  8. Electronic cigarettes: incorporating human factors engineering into risk assessments

    OpenAIRE

    Yang, Ling; Rudy, Susan F; Cheng, James M; Durmowicz, Elizabeth L

    2014-01-01

    Objective A systematic review was conducted to evaluate the impact of human factors (HF) on the risks associated with electronic cigarettes (e-cigarettes) and to identify research gaps. HF is the evaluation of human interactions with products and includes the analysis of user, environment and product complexity. Consideration of HF may mitigate known and potential hazards from the use and misuse of a consumer product, including e-cigarettes. Methods Five databases were searched through Januar...

  9. Influence of connectivity, wild prey and disturbance on occupancy of tigers in the human-dominated western Terai Arc Landscape.

    Directory of Open Access Journals (Sweden)

    Abishek Harihar

    Full Text Available Occupying only 7% of their historical range and confined to forested habitats interspersed in a matrix of human dominated landscapes, tigers (Panthera tigris typify the problems faced by most large carnivores worldwide. With heads of governments of tiger range countries pledging to reverse the extinction process and setting a goal of doubling wild tiger numbers by 2022, achieving this target would require identifying existing breeding cores, potential breeding habitats and opportunities for dispersal. The Terai Arc Landscape (TAL represents one region which has recently witnessed recovery of tiger populations following conservation efforts. In this study, we develop a spatially explicit tiger occupancy model with survey data from 2009-10 based on a priori knowledge of tiger biology and specific issues plaguing the western TAL (6,979 km(2, which occurs in two disjunct units (Tiger Habitat Blocks; THBs. Although the overall occupancy of tigers was 0.588 (SE 0.071, our results clearly indicate that loss in functionality of a regional corridor has resulted in tigers now occupying 17.58% of the available habitat in THB I in comparison to 88.5% in THB II. The current patterns of occupancy were best explained by models incorporating the interactive effect of habitat blocks (AIC w = 0.883 on wild prey availability (AIC w = 0.742 and anthropogenic disturbances (AIC w = 0.143. Our analysis has helped identify areas of high tiger occupancy both within and outside existing protected areas, which highlights the need for a unified control of the landscape under a single conservation unit with the primary focus of managing tigers and associated wildlife. Finally, in the light of global conservation targets and recent legislations in India, our study assumes significance as we identify opportunities to secure (e.g. THB II and increase (e.g. THB I tiger populations in the landscape.

  10. Coupled motions direct electrons along human microsomal P450 Chains.

    Directory of Open Access Journals (Sweden)

    Christopher R Pudney

    2011-12-01

    Full Text Available Protein domain motion is often implicated in biological electron transfer, but the general significance of motion is not clear. Motion has been implicated in the transfer of electrons from human cytochrome P450 reductase (CPR to all microsomal cytochrome P450s (CYPs. Our hypothesis is that tight coupling of motion with enzyme chemistry can signal "ready and waiting" states for electron transfer from CPR to downstream CYPs and support vectorial electron transfer across complex redox chains. We developed a novel approach to study the time-dependence of dynamical change during catalysis that reports on the changing conformational states of CPR. FRET was linked to stopped-flow studies of electron transfer in CPR that contains donor-acceptor fluorophores on the enzyme surface. Open and closed states of CPR were correlated with key steps in the catalytic cycle which demonstrated how redox chemistry and NADPH binding drive successive opening and closing of the enzyme. Specifically, we provide evidence that reduction of the flavin moieties in CPR induces CPR opening, whereas ligand binding induces CPR closing. A dynamic reaction cycle was created in which CPR optimizes internal electron transfer between flavin cofactors by adopting closed states and signals "ready and waiting" conformations to partner CYP enzymes by adopting more open states. This complex, temporal control of enzyme motion is used to catalyze directional electron transfer from NADPH→FAD→FMN→heme, thereby facilitating all microsomal P450-catalysed reactions. Motions critical to the broader biological functions of CPR are tightly coupled to enzyme chemistry in the human NADPH-CPR-CYP redox chain. That redox chemistry alone is sufficient to drive functionally necessary, large-scale conformational change is remarkable. Rather than relying on stochastic conformational sampling, our study highlights a need for tight coupling of motion to enzyme chemistry to give vectorial electron

  11. [Identification of ecological corridors for Tibetan antelope and assessment of their human disturbances in the alpine desert of Qinghai-Tibet Plateau].

    Science.gov (United States)

    Zhuge, Hai-jin; Lin, Dan-qi; Li, Xiao-wen

    2015-08-01

    The alpine desert of Qinghai-Tibet Plateau (QTP) provides the largest habitats for those endangered ungulates (e.g., Tibetan antelope, Tibetan Kiang and wild yak) on the earth. However, human disturbance especially infrastructure constructions (e.g., railway & highway) has increasingly fragmented the habitats of those endangered ungulates by disturbing and interrupting their ecological corridors for their seasonal migration. Aiming at identifying the potential ecological corridors for Tibetan antelope, a GIS-based model-Linkage Mapper was used to model and detect the potential ecological corridors of Tibetan antelope based on the principle of least cost path. Three categories of ecological corridors, i. e., closed (inside reserves), linking (linking the reserves) and open (starting from reserve but ending outside) corridors were distinguished by their spatial interactions with existing major national nature reserves (i.e., Altun, Kekexili and Qiangtang NNRs) in the alpine desert of QTP, and their spatial patterns, conservation status associated with human disturbance were also examined. Although our research indicated a general ecological integration of both habitats and ecological corridors in the alpine desert ecosystem, increasing human disturbance should not be ignored, which particularly partially undermined the functioning of those ecological corridors linking the nature reserves. Considering disadvantages of prevailing separate administrative structure of nature reserve on the effective conservation of ecological corridors for those endangered ungulates, a coordinative conservation network among these major national nature reserves should be established to ensure the unified trans-boundary conservation efforts and to enhance its overall conservation efficacy by sharing information, knowledge and optimizing conservation resources.

  12. Disturbance hydrology: Preparing for an increasingly disturbed future

    Science.gov (United States)

    Mirus, Benjamin B.; Ebel, Brian A.; Mohr, Christian H.; Zegre, Nicolas

    2017-01-01

    This special issue is the result of several fruitful conference sessions on disturbance hydrology, which started at the 2013 AGU Fall Meeting in San Francisco and have continued every year since. The stimulating presentations and discussions surrounding those sessions have focused on understanding both the disruption of hydrologic functioning following discrete disturbances, as well as the subsequent recovery or change within the affected watershed system. Whereas some hydrologic disturbances are directly linked to anthropogenic activities, such as resource extraction, the contributions to this special issue focus primarily on those with indirect or less pronounced human involvement, such as bark-beetle infestation, wildfire, and other natural hazards. However, human activities are enhancing the severity and frequency of these seemingly natural disturbances, thereby contributing to acute hydrologic problems and hazards. Major research challenges for our increasingly disturbed planet include the lack of continuous pre- and post-disturbance monitoring, hydrologic impacts that vary spatially and temporally based on environmental and hydroclimatic conditions, and the preponderance of overlapping or compounding disturbance sequences. In addition, a conceptual framework for characterizing commonalities and differences among hydrologic disturbances is still in its infancy. In this introduction to the special issue, we advance the fusion of concepts and terminology from ecology and hydrology to begin filling this gap. We briefly explore some preliminary approaches for comparing different disturbances and their hydrologic impacts, which provides a starting point for further dialogue and research progress.

  13. Accounting for regional variation in both natural environment and human disturbance to improve performance of multimetric indices of lotic benthic diatoms.

    Science.gov (United States)

    Tang, Tao; Stevenson, R Jan; Infante, Dana M

    2016-10-15

    Regional variation in both natural environment and human disturbance can influence performance of ecological assessments. In this study we calculated 5 types of benthic diatom multimetric indices (MMIs) with 3 different approaches to account for variation in ecological assessments. We used: site groups defined by ecoregions or diatom typologies; the same or different sets of metrics among site groups; and unmodeled or modeled MMIs, where models accounted for natural variation in metrics within site groups by calculating an expected reference condition for each metric and each site. We used data from the USEPA's National Rivers and Streams Assessment to calculate the MMIs and evaluate changes in MMI performance. MMI performance was evaluated with indices of precision, bias, responsiveness, sensitivity and relevancy which were respectively measured as MMI variation among reference sites, effects of natural variables on MMIs, difference between MMIs at reference and highly disturbed sites, percent of highly disturbed sites properly classified, and relation of MMIs to human disturbance and stressors. All 5 types of MMIs showed considerable discrimination ability. Using different metrics among ecoregions sometimes reduced precision, but it consistently increased responsiveness, sensitivity, and relevancy. Site specific metric modeling reduced bias and increased responsiveness. Combined use of different metrics among site groups and site specific modeling significantly improved MMI performance irrespective of site grouping approach. Compared to ecoregion site classification, grouping sites based on diatom typologies improved precision, but did not improve overall performance of MMIs if we accounted for natural variation in metrics with site specific models. We conclude that using different metrics among ecoregions and site specific metric modeling improve MMI performance, particularly when used together. Applications of these MMI approaches in ecological assessments

  14. Effects of electronic cigarette smoking on human health.

    Science.gov (United States)

    Meo, S A; Al Asiri, S A

    2014-01-01

    Electronic cigarette smoking is gaining dramatic popularity and is steadily spreading among the adolescents, high income, urban population around the world. The aim of this study is to highlight the hazards of e-cigarette smoking on human health. In this study, we identified 38 published studies through a systematic database searches including ISI-web of science and pub-med. We searched the related literature by using the key words including Electronic cigarette, E-cigarette, E-vapers, incidence, hazards. Studies in which electronic cigarette smoking hazards was investigated were included in the study. No limitations on publication status, study design of publication were implemented. Finally we included 28 publications and remaining 10 were excluded. E-smoking can cause, nausea, vomiting, headache, dizziness, choking, burn injuries, upper respiratory tract irritation, dry cough, dryness of the eyes and mucous membrane, release of cytokines and pro-inflammatory mediators, allergic airway inflammation, decreased exhaled nitric oxide (FeNO) synthesis in the lungs, change in bronchial gene expression and risk of lung cancer. Electronic cigarettes are swiftly promoted as an alternative to conventional cigarette smoking, although its use is highly controversial. Electronic cigarettes are not a smoking cessation product. Non-scientific claims about e-cigarettes are creating confusion in public perception about e-cigarette and people believe that e-cigarettes are safe and less addictive, but its use is unsafe and hazardous to human health. E-cigarette smoking should be regulated in the same way as traditional cigarettes and must be prohibited to children and adolescents.

  15. Electronic Document Management: A Human Resource Management Case Study

    Directory of Open Access Journals (Sweden)

    Thomas Groenewald

    2004-11-01

    Full Text Available This case study serve as exemplar regarding what can go wrong with the implementation of an electronic document management system. Knowledge agility and knowledge as capital, is outlined against the backdrop of the information society and knowledge economy. The importance of electronic document management and control is sketched thereafter. The literature review is concluded with the impact of human resource management on knowledge agility, which includes references to the learning organisation and complexity theory. The intervention methodology, comprising three phases, follows next. The results of the three phases are presented thereafter. Partial success has been achieved with improving the human efficacy of electronic document management, however the client opted to discontinue the system in use. Opsomming Die gevalle studie dien as voorbeeld van wat kan verkeerd loop met die implementering van ’n elektroniese dokumentbestuur sisteem. Teen die agtergrond van die inligtingsgemeenskap en kennishuishouding word kennissoepelheid en kennis as kapitaal bespreek. Die literatuurstudie word afgesluit met die inpak van menslikehulpbronbestuur op kennissoepelheid, wat ook die verwysings na die leerorganisasie en kompleksietydsteorie insluit. Die metodologie van die intervensie, wat uit drie fases bestaan, volg daarna. Die resultate van die drie fases word vervolgens aangebied. Slegs gedeelte welslae is behaal met die verbetering van die menslike doeltreffendheid ten opsigte van elektroniese dokumentbestuur. Die klient besluit egter om nie voort te gaan om die huidige sisteem te gebruik nie.

  16. Analysis of Human Resources Management Strategy in China Electronic Commerce Enterprises

    Science.gov (United States)

    Shao, Fang

    The paper discussed electronic-commerce's influence on enterprise human resources management, proposed and proved the human resources management strategy which electronic commerce enterprise should adopt from recruitment strategy to training strategy, keeping talent strategy and other ways.

  17. Disturbances in the cerebral perfusion of human immune deficiency virus-1 seropositive asymptomatic subjects: A quantitative tomography study of 18 cases

    International Nuclear Information System (INIS)

    Tran Dinh, Y.R.; Mamo, H.; Cervoni, J.; Caulin, C.; Saimot, A.C.

    1990-01-01

    Quantitative measurements of cerebral blood flow (CBF) by xenon-133 ( 133 Xe) tomography, together with magnetic resonance imaging (MRI), electroencephalography (EEG), psychometric tests, and laboratory analyses were performed on 18 human immunodeficiency virus 1 (HIV-1) seropositive asymptomatic subjects. Abnormalities of cerebral perfusion were observed in 16 cases (88%). These abnormalities were particularly frequent in the frontal regions (77% of cases). MRI demonstrated leucoencephalopathy in only two cases. EEG showed only induced diffuse abnormalities in two cases. Psychometric tests showed restricted moderate disturbances in 55% of patients. These disturbances mostly concerned those sectors involved in cognitive functions and memorization. These results indicate that quantitative measurements of CBF by 133 Xe-SPECT is capable of detecting abnormalities of cerebral perfusion at a very early stage (Phase II) of HIV-1 infection. These abnormalities are indications of disturbances resulting from unidentified metabolic or vascular lesions. This technique appears to be superior to MRI at this stage of the disease's development. It could provide objective information leading to earlier treatment, and prove useful in evaluating potential antiviral chemotherapy

  18. Disturbance Hydrology: Preparing for an Increasingly Disturbed Future

    Science.gov (United States)

    Mirus, Benjamin B.; Ebel, Brian A.; Mohr, Christian H.; Zegre, Nicolas

    2017-12-01

    This special issue is the result of several fruitful conference sessions on disturbance hydrology, which started at the 2013 AGU Fall Meeting in San Francisco and have continued every year since. The stimulating presentations and discussions surrounding those sessions have focused on understanding both the disruption of hydrologic functioning following discrete disturbances, as well as the subsequent recovery or change within the affected watershed system. Whereas some hydrologic disturbances are directly linked to anthropogenic activities, such as resource extraction, the contributions to this special issue focus primarily on those with indirect or less pronounced human involvement, such as bark-beetle infestation, wildfire, and other natural hazards. However, human activities are enhancing the severity and frequency of these seemingly natural disturbances, thereby contributing to acute hydrologic problems and hazards. Major research challenges for our increasingly disturbed planet include the lack of continuous pre and postdisturbance monitoring, hydrologic impacts that vary spatially and temporally based on environmental and hydroclimatic conditions, and the preponderance of overlapping or compounding disturbance sequences. In addition, a conceptual framework for characterizing commonalities and differences among hydrologic disturbances is still in its infancy. In this introduction to the special issue, we advance the fusion of concepts and terminology from ecology and hydrology to begin filling this gap. We briefly explore some preliminary approaches for comparing different disturbances and their hydrologic impacts, which provides a starting point for further dialogue and research progress.

  19. Fumaric acid esters can block pro-inflammatory actions of human CRP and ameliorate metabolic disturbances in transgenic spontaneously hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Jan Šilhavý

    Full Text Available Inflammation and oxidative stress have been implicated in the pathogenesis of metabolic disturbances. Esters of fumaric acid, mainly dimethyl fumarate, exhibit immunomodulatory, anti-inflammatory, and anti-oxidative effects. In the current study, we tested the hypothesis that fumaric acid ester (FAE treatment of an animal model of inflammation and metabolic syndrome, the spontaneously hypertensive rat transgenically expressing human C-reactive protein (SHR-CRP, will ameliorate inflammation, oxidative stress, and metabolic disturbances. We studied the effects of FAE treatment by administering Fumaderm, 10 mg/kg body weight for 4 weeks, to male SHR-CRP. Untreated male SHR-CRP rats were used as controls. All rats were fed a high sucrose diet. Compared to untreated controls, rats treated with FAE showed significantly lower levels of endogenous CRP but not transgenic human CRP, and amelioration of inflammation (reduced levels of serum IL6 and TNFα and oxidative stress (reduced levels of lipoperoxidation products in liver, heart, kidney, and plasma. FAE treatment was also associated with lower visceral fat weight and less ectopic fat accumulation in liver and muscle, greater levels of lipolysis, and greater incorporation of glucose into adipose tissue lipids. Analysis of gene expression profiles in the liver with Affymetrix arrays revealed that FAE treatment was associated with differential expression of genes in pathways that involve the regulation of inflammation and oxidative stress. These findings suggest potentially important anti-inflammatory, anti-oxidative, and metabolic effects of FAE in a model of inflammation and metabolic disturbances induced by human CRP.

  20. Effects of human disturbance on a burrow nesting seabird Efectos de la presencia de humanos en aves marinas que anidan en madrigueras

    Directory of Open Access Journals (Sweden)

    Yuri V. Albores-Barajas

    2011-12-01

    Full Text Available During 2004, we followed 72 natural burrows to determine the effects of disturbance on breeding success of Cassin's auklets (Ptychoramphus aleuticus. We used distance from a human settlement or path in the analysis of disturbance. Birds whose burrows were closer to the path or the village had a higher rate of nest abandonment and lower breeding success compared to birds nesting further away from the path or the village. Also, older and more experienced individuals represented a larger proportion of the breeding population on less disturbed areas than on highly disturbed ones, probably as older individuals tend to arrive earlier at the breeding grounds, and failed breeders may change burrow sites to move away from disturbance. P. aleuticus are adversely affected by human activity at colonies even if birds are not handled and burrows are not opened, and this has implications for conservation, and planning of ecotourism. On the long term, this can have negative consequences for this species and others with similar characteristics.Durante el 2004 seguimos 72 nidos de la alcuela (Ptychoramphus aleuticus para determinar los efectos de disturbio en el éxito reproductivo. Utilizamos la distancia del nido a áreas asentamientos humanos o al camino como medidas de disturbio. Los nidos que estaban más cerca de los asentamientos o del camino tuvieron una tasa de abandono mayor y un éxito reproductivo menor en comparación con los nidos que estaban más alejados de las fuentes de disturbio. También observamos que en las zonas menos expuestas la proporción de adultos, con mayor experiencia, era más alta, posiblemente porque los individuos con mayor experiencia llegan antes a la zona de anidación. Las alcuelas son afectadas negativamente por la presencia de los humanos y sus actividades, aunque las aves no entren en contacto directo con los humanos. A largo plazo, esto puede acarrear consecuencias graves para esta especie y otras con caracter

  1. Trace element content and molecular biodiversity in the epiphytic moss Leptodon smithii: two independent tracers of human disturbance.

    Science.gov (United States)

    Spagnuolo, Valeria; Terracciano, Stefano; Giordano, Simonetta

    2009-03-01

    This paper focuses on chemical composition of the epiphytic moss Leptodon smithii, gathered on Quercus ilex bark, assessed in seven sites located in urban and extra-urban/remote areas of southern Italy, a poorly surveyed geographic area. The concentrations of Cr, Cu, Pb and Zn in moss tissue are generally more abundant in moss gathered in the urban sites; among extra-urban/remote sites Valle delle Ferriere showed the highest metal concentrations, mostly related to an industrial activity occurred in the past. L. smithii chemistry seems influenced by airborne dust locally enhanced by erosion phenomena, long-range transport of pollutants and marine aerosols. Element content in moss is compared with genetic variability of L. smithii estimated in the same sites. Pearson's correlation coefficient between gene diversity and total element load (r=-0.851; p=0.03) suggests that anthropogenic pressure, determining habitat disturbance and fragmentation, leads both to genetic impoverishment consequent to population shrink, and to a higher accumulation in moss tissues, as a consequence of increased airborne major/trace elements. Thus, the coupled evaluation of chemical composition in mosses and gene diversity may prove a useful tool to highlight environmental disturbance in a gradient of land use.

  2. Radiation dosimetry in human bone using electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Breen, S.L.

    1995-01-01

    Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with a half-life of many years. The population of trapped unpaired electrons is proportional to the radiation dose administered to the bone and can be measured in excised bone samples using electron paramagnetic resonance (EPR). EPR spectra of synthetic hydroxyapatite, irradiated with Co-60, were obtained at room temperature and at 77 K. At room temperature, the radiation-induced signal, with a g-value of 2.001 ± 0.001 increased linearly with absorbed dose above a lower threshold of 3 Gy, up to doses of 200 Gy. In contrast with pure hydroxyapatite, EPR spectra of excised human bone showed a broad 'native' signal, due to the organic component of bone, which masks the dosimetrically important signal. This native signal is highly variable from sample to sample and precludes the use of EPR as an absolute dosimetry technique. However, after subtraction of the background signal, irradiated human bone showed a linear response with a lower limit of measurement similar to that of synthetic hydroxyapatite. Bone is an in vivo linear dosimeter which can be exploited to develop accurate estimates of the radiation dose delivered during systemic radiotherapy and teletherapy. However, improved sensitivity of the EPR dosimetry technique is necessary before it can be applied reliably in clinical situations. (author)

  3. Climate change and human disturbance can lead to local extinction of Alpine rock ptarmigan: new insight from the western Italian Alps.

    Directory of Open Access Journals (Sweden)

    Simona Imperio

    Full Text Available Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence.

  4. A method for assessing the physical recovery of Antarctic desert pavements following human-induced disturbances: a case study in the Ross Sea region of Antarctica.

    Science.gov (United States)

    O'Neill, Tanya A; Balks, Megan R; López-Martínez, Jerónimo; McWhirter, Judi L

    2012-12-15

    With increasing visitor numbers an understanding of the impacts of human activities in Antarctic terrestrial environments has become important. The objective of this study was to develop a means for assessing recovery of the ground surface desert pavement following physical disturbance. A set of 11 criteria were identified to assess desert pavement recovery. Assessed criteria were: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m(2); colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity/extent rating on a scale from zero to four, zero being highly disturbed, and four being undisturbed. A relative % recovery for each criteria was calculated for each site by comparison with a nearby undisturbed control area, and an overall Mean Recovery Index (MRI) was assigned to each pavement surface. To test the method, 54 sites in the Ross Sea region of Antarctica were investigated including areas disturbed by: bulldozer scraping for road-fill, contouring for infrastructure, geotechnical investigations, and experimental treading trial sites. Disturbances had occurred at timescales ranging from one week to 50 years prior to assessment. The extent of desert pavement recovery at the sites investigated in this study was higher than anticipated. Fifty of the 54 sites investigated were in an intermediate, or higher, stage of desert pavement recovery, 30 sites were in an advanced stage of recovery, and four sites were indistinguishable from adjacent control sites (MRI = 100%). It was found that active surfaces, such as the gravel beach deposits at the Greenpeace World Park Base site at Cape Evans, the aeolian sand deposits at Bull Pass, and the alluvial fan deposits of the Loop Moraine field campsite, recovered relatively

  5. Human disturbance, nursing behaviour, and lactational pup growth in a declining southern elephant seal (Mirounga leonina) population

    NARCIS (Netherlands)

    Engelhard, GH; Baarspul, ANJ; Broekman, M; Creuwels, JCS; Reijnders, PJH

    We studied lactation behaviour in relation to pup growth in southern elephant seals (Mirounga leonina) at Macquarie Island, and compared harems in areas of high and low human presence to determine if there is an effect attributable to human activities, including scientific research. Pup weaning

  6. Human disturbance, nursing behaviour, and lactational pup growth in a declining southern elephant seal (Mirounga leonina) population

    NARCIS (Netherlands)

    Engelhard, G.H.; Baarspul, A.N.J.; Broekman, M.; Creuwels, J.C.S.; Reijnders, P.J.H.

    2002-01-01

    We studied lactation behaviour in relation to pup growth in southern elephant seals (Mirounga leonina) at Macquarie Island, and compared harems in areas of high and low human presence to determine if there is an effect attributable to human activitiesincluding scientific research. Pup weaning mass,

  7. Tracking Human-Induced Landscape Disturbance at the Nasca Lines UNESCO World Heritage Site in Peru with COSMO-SkyMed InSAR

    Directory of Open Access Journals (Sweden)

    Francesca Cigna

    2018-04-01

    Full Text Available The “Lines and Geoglyphs of Nasca and Palpa” in Peru are among the most well-known UNESCO World Heritage Sites globally, and an exemplar of site where heritage assets cannot be separated from their natural and anthropogenic environment. The site is exposed to interactions with natural processes, as well as human presence. In this work, 3-m resolution synthetic aperture radar (SAR StripMap HIMAGE HH-polarised scenes acquired by the X-band COSMO-SkyMed constellation are exploited to track two events of human-induced landscape disturbance that occurred in December 2014 and January 2018. Pre-, cross-, and post-event interferometric SAR (InSAR pairs characterised by small temporal and normal baselines allow the detection of temporal decorrelation associated with the two events, the extent and time reference of which match with online photographic and video evidence, published literature, web news, and press releases by the Ministry of Culture in Peru. Further elements enhancing the understanding of the 2018 event come from 10-m resolution Sentinel-2B satellite data that reveal the occurrence of apparent changes of surface reflectance due to uncovering of the light grey-yellow clay underneath the darker pebble constituting the fragile surface of the Pampa de Jumana. This scientific study confirms that SAR imagery archives, such as those being built by COSMO-SkyMed for Nasca, prove valuable for the retrospective analysis and digital recording of human-induced landscape disturbance events from space. These archives therefore act as essential sources of geospatial information on the conservation history of heritage sites and assets.

  8. Flexible and wearable electronic silk fabrics for human physiological monitoring

    Science.gov (United States)

    Mao, Cuiping; Zhang, Huihui; Lu, Zhisong

    2017-09-01

    The development of textile-based devices for human physiological monitoring has attracted tremendous interest in recent years. However, flexible physiological sensing elements based on silk fabrics have not been realized. In this paper, ZnO nanorod arrays are grown in situ on reduced graphene oxide-coated silk fabrics via a facile electro-deposition method for the fabrication of silk-fabric-based mechanical sensing devices. The data show that well-aligned ZnO nanorods with hexagonal wurtzite crystalline structures are synthesized on the conductive silk fabric surface. After magnetron sputtering of gold electrodes, silk-fabric-based devices are produced and applied to detect periodic bending and twisting. Based on the electric signals, the deformation and release processes can be easily differentiated. Human arterial pulse and respiration can also be real-time monitored to calculate the pulse rate and respiration frequency, respectively. Throat vibrations during coughing and singing are detected to demonstrate the voice recognition capability. This work may not only help develop silk-fabric-based mechanical sensing elements for potential applications in clinical diagnosis, daily healthcare monitoring and voice recognition, but also provide a versatile method for fabricating textile-based flexible electronic devices.

  9. The sinusoidal lining cells in "normal" human liver. A scanning electron microscopic investigation

    DEFF Research Database (Denmark)

    Horn, T; Henriksen, Jens Henrik Sahl; Christoffersen, P

    1986-01-01

    The scanning electron microscopic was used to study the fenestrations of human liver sinusoids. Thirteen biopsies, where light microscopy and transmission electron microscopy revealed normal sinusoidal architecture, were investigated. The number of fenestrae was calculated in acinar zone 3...

  10. Acute encephalopathy with concurrent respiratory and metabolic disturbances in first known parenteral human administration of flunixin meglumine and acepromazine maleate.

    Science.gov (United States)

    Kamali, Michael F; Wilson, Anwar C; Acquisto, Nicole M; Spillane, Linda; Schneider, Sandra M

    2013-08-01

    Flunexin is a nonsteroidal anti-inflammatory drug approved for veterinary use in horses and cattle. Acepromazine is a phenothiazine derivative used in horses, dogs, and cats. Human exposure to these substances is rare. We report a case of a human injection of two equine medications, flunixin and acepromazine, which resulted in altered mental status, respiratory alkalosis, gastrointestinal bleeding, and elevation of liver transaminases in a 43-year-old woman who worked as a horse trainer. The patient intentionally self-injected these medications and subsequently presented to the Emergency Department with altered mental status and lethargy. The patient required hospitalization for metabolic abnormalities, including respiratory alkalosis, and suffered a gastrointestinal bleed requiring blood transfusion. The patient ultimately recovered with supportive measures. We believe this to be the first case of concomitant injection of flunixin and acepromazine in a human. This report explains a case of parenteral administration of two equine medications and the subsequent complications in a patient that presented to the Emergency Department. Human exposure to veterinary medications cannot be predicted by their effect in animals due to variations in absorption, distribution, and metabolism. Physicians should be aware that individuals who work with animals may have access to large quantities of veterinary medicine. This case also exemplifies the challenges that Emergency Physicians face on a daily basis, and generates additional consideration for overdoses and intoxications from medications that are not considered commonplace in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Disturbances of ligand potency and enhanced degradation of the human glycine receptor at affected positions G160 and T162 originally identified in patients suffering from hyperekplexia

    Directory of Open Access Journals (Sweden)

    Sinem eAtak

    2015-12-01

    Full Text Available Ligand-binding of Cys-loop receptors is determined by N-terminal extracellular loop structures from the plus as well as from the minus side of two adjacent subunits in the pentameric receptor complex. An aromatic residue in loop B of the glycine receptor (GlyR undergoes direct interaction with the incoming ligand via cation-π interactions. Recently we showed that mutated residues in loop B identified from human patients suffering from hyperekplexia disturb ligand-binding. Here, we exchanged the affected human residues by amino acids found in related members of the Cys-loop receptor family to determine the effects of side chain volume for ion channel properties. GlyR variants were characterized in vitro following transfection into cell lines in order to analyze protein expression, trafficking, degradation and ion channel function. GlyR α1 G160 mutations significantly decrease glycine potency arguing for a positional effect on neighboring aromatic residues and consequently glycine-binding within the ligand-binding pocket. Disturbed glycinergic inhibition due to T162 α1 mutations is an additive effect of affected biogenesis and structural changes within the ligand-binding site. Protein trafficking from the ER towards ER-Golgi intermediate compartment, the secretory Golgi pathways and finally the cell surface is largely diminished, but still sufficient to deliver ion channels that are functional at least at high glycine concentrations. The majority of T162 mutant protein accumulates in the ER and is conducted to ER-associated proteasomal degradation. Hence, G160 is an important determinant during glycine binding. In contrast, T162 assigns primarily receptor biogenesis whereas exchanges in functionality are secondary effects thereof.

  12. Great gray owls (Strix nebulosa) in Yosemite National Park: on the importance of food, forest structure, and human disturbance

    Science.gov (United States)

    van Riper, Charles; Fontaine, Joseph J.; van Wagtendonk, Jan W.

    2013-01-01

    We studied great gray owls (Strix nebulosa Forster) in Yosemite National Park, California, measuring variables that could potentially influence patterns of occurrence and conservation of this stateendangered species. We found that owl presence was closely tied to habitat (red fir (Abies magnified A. Murray) and the abundance of meadows), prey, and snags across the landscape. We also found that indicators of human recreational activities negatively influenced owl distribution and habitat use. Great gray owls appear to prefer mid-elevation red fir forest with meadows that are drier and more productive in terms of small mammal populations. That these areas also have the highest human activity presents a paradox, both for individual owls and for the future conservation and management of this California endangered species. The extent to which human recreation in natural areas affects animal behavior, species distribution, and productivity is a growing issue in natural area management. We present information that will allow land managers to better understand how existing natural resources, coupled with human recreation, influence the distribution and habitat use of the great gray owl.

  13. Changing Forest Disturbance Regimes and Risk Perceptions in Homer, Alaska

    Science.gov (United States)

    Courtney G. F1int

    2007-01-01

    Forest disturbances caused by insects can lead to other disturbances, risks, and changes across landscapes. Evaluating the human dimensions of such disturbances furthers understanding of integrated changes in natural and social systems. This article examines the effects of changing forest disturbance regimes on local risk perceptions and attitudes in Homer, Alaska....

  14. Release of tensile strain on engineered human tendon tissue disturbs cell adhesions, changes matrix architecture, and induces an inflammatory phenotype

    DEFF Research Database (Denmark)

    Bayer, Monika L; Schjerling, Peter; Herchenhan, Andreas

    2014-01-01

    Mechanical loading of tendon cells results in an upregulation of mechanotransduction signaling pathways, cell-matrix adhesion and collagen synthesis, but whether unloading removes these responses is unclear. We investigated the response to tension release, with regard to matrix proteins, pro......-inflammatory mediators and tendon phenotypic specific molecules, in an in vitro model where tendon-like tissue was engineered from human tendon cells. Tissue sampling was performed 1, 2, 4 and 6 days after surgical de-tensioning of the tendon construct. When tensile stimulus was removed, integrin type collagen receptors...... were upregulated. Stimulation with the cytokine TGF-β1 had distinct effects on some tendon-related genes in both tensioned and de-tensioned tissue. These findings indicate an important role of mechanical loading for cellular and matrix responses in tendon, including that loss of tension leads...

  15. Disturbed mitochondrial function restricts glutamate uptake in the human Müller glia cell line, MIO-M1

    DEFF Research Database (Denmark)

    Vohra, Rupali; Gurubaran, Iswariyaraja Sridevi; Henriksen, Ulrik

    2017-01-01

    Using the human Müller cell line, MIO-M1, the aim was to study the impact of mitochondrial inhibition in Müller glia through antimycin A treatment. MIO-M1 cell survival, levels of released lactate, mitochondrial function, and glutamate uptake were studied in response to mitochondrial inhibition...... and glucose restriction. Lactate release decreased in response to glucose restriction. Combined glucose restriction and blocked mitochondrial activity decreased survival and caused collapse of the respiratory chain measured by oxygen consumption rate and extracellular acidification rate. Mitochondrial...... inhibition caused impaired glutamate uptake and decreased mRNA expression of the glutamate transporter, EAAT1. Over all, we show important roles of mitochondrial activity in MIO-M1 cell function and survival....

  16. Plasma levels of 27-hydroxycholesterol in humans and mice with monogenic disturbances of high density lipoprotein metabolism

    DEFF Research Database (Denmark)

    Karuna, Ratna; Holleboom, Adriaan G; Motazacker, Mohammad M

    2011-01-01

    Secretion of 27-hydroxycholesterol (27OHC) from macrophages is considered as an alternative to HDL-mediated reverse transport of excess cholesterol. We investigated 27OHC-concentrations in plasma of humans and mice with monogenic disorders of HDL metabolism. As compared to family controls mutations...... activities of LCAT and CETP, respectively, than the formation and transfer of cholesterylesters. 27OHC plasma levels were also decreased in apoA-I-, ABCA1- or LCAT-knockout mice but increased in SR-BI-knockout mice. Transplantation of ABCA1- and/or ABCG1-deficient bone marrow into LDL receptor deficient mice...... decreased plasma levels of 27OHC. In conclusion, mutations or absence of HDL genes lead to distinct alterations in the quantity, esterification or lipoprotein distribution of 27OHC. These findings argue against the earlier suggestion that 27OHC-metabolism in plasma occurs independently of HDL....

  17. Pleistocene climatic oscillations rather than recent human disturbance influence genetic diversity in one of the world's highest treeline species.

    Science.gov (United States)

    Peng, Yanling; Lachmuth, Susanne; Gallegos, Silvia C; Kessler, Michael; Ramsay, Paul M; Renison, Daniel; Suarez, Ricardo; Hensen, Isabell

    2015-10-01

    Biological responses to climatic change usually leave imprints on the genetic diversity and structure of plants. Information on the current genetic diversity and structure of dominant tree species has facilitated our general understanding of phylogeographical patterns. Using amplified fragment length polymorphism (AFLPs), we compared genetic diversity and structure of 384 adults of P. tarapacana with those of 384 seedlings across 32 forest sites spanning a latitudinal gradient of 600 km occurring between 4100 m and 5000 m a.s.l. in Polylepis tarapacana (Rosaceae), one of the world's highest treeline species endemic to the central Andes. Moderate to high levels of genetic diversity and low genetic differentiation were detected in both adults and seedlings, with levels of genetic diversity and differentiation being almost identical. Four slightly genetically divergent clusters were identified that accorded to differing geographical regions. Genetic diversity decreased from south to north and with increasing precipitation for adults and seedlings, but there was no relationship to elevation. Our study shows that, unlike the case for other Andean treeline species, recent human activities have not affected the genetic structure of P. tarapacana, possibly because its inhospitable habitat is unsuitable for agriculture. The current genetic pattern of P. tarapacana points to a historically more widespread distribution at lower altitudes, which allowed considerable gene flow possibly during the glacial periods of the Pleistocene epoch, and also suggests that the northern Argentinean Andes may have served as a refugium for historical populations. © 2015 Botanical Society of America.

  18. Disturbance of gene expression in primary human hepatocytes by hepatotoxic pyrrolizidine alkaloids: A whole genome transcriptome analysis.

    Science.gov (United States)

    Luckert, Claudia; Hessel, Stefanie; Lenze, Dido; Lampen, Alfonso

    2015-10-01

    1,2-unsaturated pyrrolizidine alkaloids (PA) are plant metabolites predominantly occurring in the plant families Asteraceae and Boraginaceae. Acute and chronic PA poisoning causes severe hepatotoxicity. So far, the molecular mechanisms of PA toxicity are not well understood. To analyze its mode of action, primary human hepatocytes were exposed to a non-cytotoxic dose of 100 μM of four structurally different PA: echimidine, heliotrine, senecionine, senkirkine. Changes in mRNA expression were analyzed by a whole genome microarray. Employing cut-off values with a |fold change| of 2 and a q-value of 0.01, data analysis revealed numerous changes in gene expression. In total, 4556, 1806, 3406 and 8623 genes were regulated by echimidine, heliotrine, senecione and senkirkine, respectively. 1304 genes were identified as commonly regulated. PA affected pathways related to cell cycle regulation, cell death and cancer development. The transcription factors TP53, MYC, NFκB and NUPR1 were predicted to be activated upon PA treatment. Furthermore, gene expression data showed a considerable interference with lipid metabolism and bile acid flow. The associated transcription factors FXR, LXR, SREBF1/2, and PPARα/γ/δ were predicted to be inhibited. In conclusion, though structurally different, all four PA significantly regulated a great number of genes in common. This proposes similar molecular mechanisms, although the extent seems to differ between the analyzed PA as reflected by the potential hepatotoxicity and individual PA structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Human Milk, Environmental Toxins and Pollution of Our Infants: Disturbing Findings during the First Six Months of Life.

    Science.gov (United States)

    Lackmann, Gerd-Michael

    2006-06-01

    Toxic organochlorine compounds (OC) are transmitted from mother to infant during lactation. OC are ingested by and stored in their offspring. Different harmful effects later in life have been attributed to the body pollution with these OC, although these findings are still discussed in an argumentative manner, since first other investigators could demonstrate beneficial effects of breast-feeding despite elevated OC concentrations, and second the benefits of breast-feeding are an unchallenged fact, especially in those countries, where infant formulas are not available. It was the aim of the present study to determine the lactational uptake of different OC (polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), and DDE) in breast-fed vs. bottle-fed infants up to six months of age. With the written informed consent of the parents, blood samples were taken from each ten breast-fed and bottle-fed infants, respectively. The specimens were immediately centrifuged, and serum was stored in glass tubes without an anticoagulant up to analysis. Three higher-chlorinated PCB congeners (IUPAC Nos. 138, 153, and 180), HCB, and DDE, the main metabolite of DDT in mammals, were determined with capillary gas chromatography with electron capture detection. In addition, reliability was tested with gas chromatography-mass spectrometry. Possible correlations of OC with personal data were tested with a standard multivariate regression model. Differences between study groups were tested on mean differences with Wilcoxons test for independent samples. We could demonstrate that breast-fed infants have significantly (p<0.0001) elevated serum concentrations of all OC as early as at the age of six weeks (90%), which over and above nearly doubled further until the age of six months. (Median (μg/L); A=six weeks; B=six months): PCB 138, A: 0.40 vs. 0.09; B: 0.72 vs. 0.07; PCB 153, A: 0.57 vs. 0.11; B: 0.99 vs. 0.09; PCB 180, A: 0.33 vs. 0.04; B: 0.58 vs. 0.02; PCB (sum of the three PCB

  20. Computer aided analysis of disturbances

    International Nuclear Information System (INIS)

    Baldeweg, F.; Lindner, A.

    1986-01-01

    Computer aided analysis of disturbances and the prevention of failures (diagnosis and therapy control) in technological plants belong to the most important tasks of process control. Research in this field is very intensive due to increasing requirements to security and economy of process control and due to a remarkable increase of the efficiency of digital electronics. This publication concerns with analysis of disturbances in complex technological plants, especially in so called high risk processes. The presentation emphasizes theoretical concept of diagnosis and therapy control, modelling of the disturbance behaviour of the technological process and the man-machine-communication integrating artificial intelligence methods, e.g., expert system approach. Application is given for nuclear power plants. (author)

  1. Urbanization and baseline prevalence of genital infections including Candida, Trichomonas, and human papillomavirus and of a disturbed vaginal ecology as established in the Dutch Cervical Screening Program

    NARCIS (Netherlands)

    Boon, ME; Claasen, HHV; Kok, LP

    OBJECTIVE: An overgrowth of coccoid bacilli in the absence of lactobacilli (bacterial vaginosis) is considered a sign of a "disturbed" vaginal ecologic system. The aim of this study was to establish the baseline prevalence of genital infections and of a disturbed vaginal ecologic system and their

  2. Secondary mineralization in carious lesions of human dentin. Electron-probe, electron microscope, and electron diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogiwara, H [Tokyo Dental Coll. (Japan)

    1975-02-01

    Dentinal carious lesions having a remineralized surface layer were studied by means electron-probe microanalysis, electron microscopy, electron diffraction. As the results of electron-probe study, F, Mg, and Na were found to be distributed mainly in the remineralized surface layer and S in the decalcified region where decreases in Ca, P, and Mg concentration were usually observed. The decrease in Mg concentration always started earlier than that of Ca and P concentration. Electron microscope and electron diffraction studies revealed that apatic crystals in the remineralized surface layer were much larger than those in the intact dentin. Although they were less conspicuous, crystals in the decalcified region also were larger than those in the intact region. Dentinal tubules, occluded by many crystals, were frequently seen during the observations. Crystals in the tubules varied in morphology, showing granular, needle, rhomboid, and tabular shapes. By means of electron diffraction, the granular- or needle-shaped crystals were identified as apatite and the rhomboid-shaped crystals as whitlockite. Some of the tabular-shaped crystals appeared to be cotacalcium phosphate.

  3. Scanning electron microscopy and electron probe microanalyses of the crystalline components of human and animal dental calculi

    International Nuclear Information System (INIS)

    LeGeros, R.Z.; Orly, I.; LeGeros, J.P.; Gomez, C.; Kazimiroff, J.; Tarpley, T.; Kerebel, B.

    1988-01-01

    A review of the use of scanning electron microscopy (SEM) and electron probe microanalyses in the study of dental calculus showed that such studies provided confirmatory and supplementary data on the morphological features of human dental calculi but gave only limited information on the identity of the crystalline or inorganic components. This study aimed to explore the potential of combined SEM and microanalyses in the identification of the crystalline components of the human and animal dental calculi. Human and animal calculi were analyzed. Identification of the crystalline components were made based on the combined information of the morphology (SEM) and Ca/P molar ratios of the crystals with the morphology and Ca/P molar ratio of synthetic calcium phosphates (brushite or DCPD; octacalcium phosphate, OCP; Mg-substituted whitlockite, beta-TCMP; CO 3 -substituted apatite, (CHA); and calcite. SEM showed similarities in morphological features of human and animal dental calculi but differences in the forms of crystals present. Microanalyses and crystal morphology data suggested the presence of CaCO 3 (calcite) and CHA in the animal (cat, dog, tiger) and of OCP, beta-TCMP and CHA in human dental calculi. X-ray diffraction and infrared (IR) absorption analyses confirmed these results. This exploratory study demonstrated that by taking into consideration what is known about the crystalline components of human and animal dental calculi, combined SEM and microanalyses can provide qualitative identification

  4. Selenium modulates MMP2 expression through the TGFβ1/Smad signalling pathway in human umbilical vein endothelial cells and rabbits following lipid disturbance.

    Science.gov (United States)

    Xu, Chenggui; Lu, Guihua; Li, Qinglang; Zhang, Juhong; Huang, Zhibin; Gao, Xiuren

    2017-07-01

    A high-fat diet is a major risk factor for coronary heart diseases. Matrix metalloprotease (MMP) expression is changed in many cardiovascular diseases. Selenium, which is an important trace element in animals, has a close relationship with cardiovascular diseases. The TGFβ1/Smad signalling pathway is ubiquitous in diverse tissues and cells, and it is also associated with the occurrence and development of cardiovascular diseases. Therefore, in this study, we aimed to determine selenium's effect on lipid metabolism, atherosclerotic plaque formation, and MMP2 expression, as well as the underlying functional mechanism. In vivo tests: 24 male New Zealand white rabbits were randomly divided into 4 groups: regular diet, high-fat diet, high-fat diet+selenium and regular diet+selenium groups. The high-fat diet induced the lipid disturbances of rabbits at week 12. Selenium supplementation lowered total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels (pSelenium supplementation also suppressed MMP2 over-expression in thoracic aortas. In vitro tests: Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of selenium or ox-LDL. Ox-LDL promoted MMP2 expression by increasing TGFβ1, pSmad2, pSmad3 and Smad3 expression (pSelenium attenuated MMP2 over-expression by regulating the TGFβ1/Smad signalling pathway. Selenium suppressed high-fat diet-induced MMP2 over-expression in vivo by improving lipid metabolism. In vitro, selenium attenuated MMP2 over-expression through the TGFβ1/Smad signalling pathway. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Human reproductive system disturbances and pesticide exposure in Brazil Distúrbios do sistema reprodutivo humano e exposição a pesticidas no Brasil

    Directory of Open Access Journals (Sweden)

    Sergio Koifman

    2002-04-01

    Full Text Available The observation of reproductive disturbances in humans and in the wildlife has been reported in the last decade in different countries. Exposure to different chemicals possibly acting in the endocrine system or endocrine disruptors, including pesticides, has been a hypothesis raised to explain the observed changes. This paper aimed to present results of an epidemiological ecologic study carried out to explore population data on pesticides exposure in selected Brazilian states in the eighties and human reproductive outcomes in the nineties. Pearson correlation coefficients were ascertained between available data pesticides sales in eleven states in Brazil in 1985 and selected further reproductive outcomes or their surrogates. Moderate to high correlations were observed to infertility, testis, breast, prostate and ovarian cancer mortality. Despite the restrains of ecologic studies to establish cause-effect relationships, the observed results are in agreement with evidence supporting a possible association between pesticides exposure and the analyzed reproductive outcomes.A observação de distúrbios reprodutivos em seres humanos e na vida animal tem sido relatada em diferentes países na última década, sendo apontada como possível explicação para tal fenômeno, a exposição a diversas substâncias químicas com possível interferência no sistema endócrino, incluindo pesticidas. Este trabalho apresenta os resultados de um estudo epidemiológico, com delineamento ecológico explorando dados de exposição a pesticidas durante os anos oitenta, em estados brasileiros selecionados e distúrbios reprodutivos observados nos anos noventa. Foram obtidos coeficientes de correlação de Pearson entre o volume de vendas de pesticidas em onze estados brasileiros em 1985 e indicadores diretos ou substitutos da ocorrência de distúrbios reprodutivos nas mesmas localidades. Coeficientes de correlação moderados e elevados foram observados para a

  6. Predicted and measured bottomside F-region electron density and variability of the D1 parameter under quiet and disturbed conditions over Europe

    Czech Academy of Sciences Publication Activity Database

    Burešová, Dalia; Altadill, D.; Mosert, M.; Miro, G.

    2004-01-01

    Roč. 34, č. 9 (2004), s. 1973-1981 ISSN 0273-1177 R&D Projects: GA AV ČR IAA3042102 Institutional research plan: CEZ:AV0Z3042911 Keywords : Ionosphere * Geomagnetic storm * Electron density Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.548, year: 2004

  7. A plant taxonomic survey of the Uranium City region, Lake Athabasca north shore, emphasizing the naturally colonizing plants on uranium mine and mill wastes and other human-disturbed sites

    International Nuclear Information System (INIS)

    Harms, V.L.

    1982-07-01

    A goal of this study was to acquire more complete baseline data on the existing flora of the Uranium City region, both in natural and human-disturbed sites. Emphasis was given to determining which plant species were naturally revegetating various abandoned uranium mine and mill waste disposal areas, other human-disturbed sites, and ecologically analogous sites. Another goal was to document the occurrence and distribution in the study region of rare and possibly endangered species. A further objective was to suggest regionally-occurring species with potential value for revegetating uranium mine and mill waste sites. Field investigations were carried out in the Uranium City region during August, 1981. During this time 1412 plant collections were made; a total of 366 plant species - trees, shrubs, forbs, graminoids, lichens, and bryophytes were recorded. The report includes an annotated checklist of plant species of the Uranium City region and a reference index of plant taxa indicating species that have high revegetation potential

  8. Quantification of Wine Mixtures with an Electronic Nose and a Human Panel

    Science.gov (United States)

    Aleixandre, Manuel; Cabellos, Juan M.; Arroyo, Teresa; Horrillo, M. C.

    2018-01-01

    In this work, an electronic nose and a human panel were used for the quantification of wines formed by binary mixtures of four white grape varieties and two varieties of red wines at different percentages (from 0 to 100% in 10% steps for the electronic nose and from 0 to 100% in 25% steps for the human panel). The wines were prepared using the traditional method with commercial yeasts. Both techniques were able to quantify the mixtures tested, but it is important to note that the technology of the electronic nose is faster, simpler, and more objective than the human panel. In addition, better results of quantification were also obtained using the electronic nose. PMID:29484296

  9. Influence of disturbance on temperate forest productivity

    Science.gov (United States)

    Peters, Emily B.; Wythers, Kirk R.; Bradford, John B.; Reich, Peter B.

    2013-01-01

    Climate, tree species traits, and soil fertility are key controls on forest productivity. However, in most forest ecosystems, natural and human disturbances, such as wind throw, fire, and harvest, can also exert important and lasting direct and indirect influence over productivity. We used an ecosystem model, PnET-CN, to examine how disturbance type, intensity, and frequency influence net primary production (NPP) across a range of forest types from Minnesota and Wisconsin, USA. We assessed the importance of past disturbances on NPP, net N mineralization, foliar N, and leaf area index at 107 forest stands of differing types (aspen, jack pine, northern hardwood, black spruce) and disturbance history (fire, harvest) by comparing model simulations with observations. The model reasonably predicted differences among forest types in productivity, foliar N, leaf area index, and net N mineralization. Model simulations that included past disturbances minimally improved predictions compared to simulations without disturbance, suggesting the legacy of past disturbances played a minor role in influencing current forest productivity rates. Modeled NPP was more sensitive to the intensity of soil removal during a disturbance than the fraction of stand mortality or wood removal. Increasing crown fire frequency resulted in lower NPP, particularly for conifer forest types with longer leaf life spans and longer recovery times. These findings suggest that, over long time periods, moderate frequency disturbances are a relatively less important control on productivity than climate, soil, and species traits.

  10. Classification of human pathogen bacteria for early screening using electronic nose

    Science.gov (United States)

    Zulkifli, Syahida Amani; Mohamad, Che Wan Syarifah Robiah; Abdullah, Abu Hassan

    2017-10-01

    This paper present human pathogen bacteria for early screening using electronic nose. Electronic nose (E-nose) known as gas sensor array is a device that analyze the odor measurement give the fast response and less time consuming for clinical diagnosis. Many bacterial pathogens could lead to life threatening infections. Accurate and rapid diagnosis is crucial for the successful management of these infections disease. The conventional method need more time to detect the growth of bacterial. Alternatively, the bacteria are Pseudomonas aeruginosa and Shigella cultured on different media agar can be detected and classifies according to the volatile compound in shorter time using electronic nose (E-nose). Then, the data from electronic nose (E-nose) is processed using statistical method which is principal component analysis (PCA). The study shows the capability of electronic nose (E-nose) for early screening for bacterial infection in human stomach.

  11. Effects of climate change on ecological disturbances [Chapter 8

    Science.gov (United States)

    Danielle M. Malesky; Barbara J. Bentz; Gary R. Brown; Andrea R. Brunelle; John M. Buffington; Linda M. Chappell; R. Justin DeRose; John C. Guyon; Carl L. Jorgensen; Rachel A. Loehman; Laura L. Lowrey; Ann M. Lynch; Marek Matyjasik; Joel D. McMillin; Javier E. Mercado; Jesse L. Morris; Jose F. Negron; Wayne G. Padgett; Robert A. Progar; Carol B. Randall

    2018-01-01

    This chapter describes disturbance regimes in the Intermountain Adaptation Partnership (IAP) region, and potential shifts in these regimes as a consequence of observed and projected climate change. The term "disturbance regime" describes the general temporal and spatial characteristics of a disturbance agent (e.g., insects, disease, fire, weather, human...

  12. Rapid Electrical Stimulation Increased Cardiac Apoptosis Through Disturbance of Calcium Homeostasis and Mitochondrial Dysfunction in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Le Geng

    2018-06-01

    Full Text Available Background/Aims: Heart failure induced by tachycardia, the most common arrhythmia, is frequently observed in clinical practice. This study was designed to investigate the underlying mechanisms. Methods: Rapid electrical stimulation (RES at a frequency of 3 Hz was applied on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs for 7 days, with 8 h/day and 24 h/day set to represent short-term and long-term tachycardia, respectively. Age-matched hiPSC-CMs without electrical stimulation or with slow electrical stimulation (1 Hz were set as no electrical stimulation (NES control or low-frequency electrical stimulation (LES control. Following stimulation, JC-1 staining flow cytometry analysis was performed to examine mitochondrial conditions. Apoptosis in hiPSC-CMs was evaluated using Hoechst staining and Annexin V/propidium iodide (AV/PI staining flow cytometry analysis. Calcium transients and L-type calcium currents were recorded to evaluate calcium homeostasis. Western blotting and qPCR were performed to evaluate the protein and mRNA expression levels of apoptosis-related genes and calcium homeostasis-regulated genes. Results: Compared to the controls, hiPSC-CMs following RES presented mitochondrial dysfunction and an increased apoptotic percentage. Amplitudes of calcium transients and L-type calcium currents were significantly decreased in hiPSC-CMs with RES. Molecular analysis demonstrated upregulated expression of Caspase3 and increased Bax/Bcl-2 ratio. Genes related to calcium re-sequence were downregulated, while phosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII was significantly upregulated following RES. There was no significant difference between the NES control and LES control groups in these aspects. Inhibition of CaMKII with 1 µM KN93 partly reversed these adverse effects of RES. Conclusion: RES on hiPSC-CMs disturbed calcium homeostasis, which led to mitochondrial stress, promoted cell apoptosis and

  13. Biophysical dosimetry using electron paramagnetic resonance in human tooth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

    2002-01-01

    Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

  14. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning......: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  15. Electron spin relaxation enhancement measurements of interspin distances in human, porcine, and Rhodobacter electron transfer flavoprotein ubiquinone oxidoreductase (ETF QO)

    Science.gov (United States)

    Fielding, Alistair J.; Usselman, Robert J.; Watmough, Nicholas; Simkovic, Martin; Frerman, Frank E.; Eaton, Gareth R.; Eaton, Sandra S.

    2008-02-01

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a membrane-bound electron transfer protein that links primary flavoprotein dehydrogenases with the main respiratory chain. Human, porcine, and Rhodobacter sphaeroides ETF-QO each contain a single [4Fe-4S] 2+,1+ cluster and one equivalent of FAD, which are diamagnetic in the isolated enzyme and become paramagnetic on reduction with the enzymatic electron donor or with dithionite. The anionic flavin semiquinone can be reduced further to diamagnetic hydroquinone. The redox potentials for the three redox couples are so similar that it is not possible to poise the proteins in a state where both the [4Fe-4S] + cluster and the flavoquinone are fully in the paramagnetic form. Inversion recovery was used to measure the electron spin-lattice relaxation rates for the [4Fe-4S] + between 8 and 18 K and for semiquinone between 25 and 65 K. At higher temperatures the spin-lattice relaxation rates for the [4Fe-4S] + were calculated from the temperature-dependent contributions to the continuous wave linewidths. Although mixtures of the redox states are present, it was possible to analyze the enhancement of the electron spin relaxation of the FAD semiquinone signal due to dipolar interaction with the more rapidly relaxing [4Fe-4S] + and obtain point-dipole interspin distances of 18.6 ± 1 Å for the three proteins. The point-dipole distances are within experimental uncertainty of the value calculated based on the crystal structure of porcine ETF-QO when spin delocalization is taken into account. The results demonstrate that electron spin relaxation enhancement can be used to measure distances in redox poised proteins even when several redox states are present.

  16. Comparative investigation on electron spin resonance dosimetry of tooth enamel of cow and human

    International Nuclear Information System (INIS)

    Jiao Ling; Zhang Wenyi; Ding Yanqiu; Kou Mingying

    2010-01-01

    The enamel samples from cow teeth and human teeth were irradiated with 137 Cs γ ray. Their electron spin resonance (ESR) spectra pre and post-irradiation were weaker than those of human. Mass of each sample is 100 mg, the dosimetric signal intensity of cow enamel increased with the radiation dose; the averaged radiation response of cow samples was (34.4±2.0) Gy -1 , very close to the average response of human tooth samples (36.3±2.9) Gy -1 . Therefore cow teeth can be used for retrospective radiation dosimetry when human teeth are unavailable. (authors)

  17. Neurobiological basis of parenting disturbance.

    Science.gov (United States)

    Newman, Louise K; Harris, Melissa; Allen, Joanne

    2011-02-01

    It has been proposed that early attachment relationships shape the structure and reactivity of social brain structures that underlie later social capacities. We provide a review of the literature surrounding the development of neurological regulatory systems during infancy and outline recent research suggesting these systems go on to underlie adaptive parental responses. We review evidence in the peer-reviewed psychiatric literature including (i) observational human literature on the neurobiological and social sequelae of early parenting experiences, (ii) experimental animal literature on the effects of early maternal care on neurological development, (iii) experimental animal literature on the neurobiological underpinnings of parenting behaviours, (iv) observational and fMRI evidence on the neurobiological correlates of parenting behaviours, (v) functional and volumetric imaging studies on adults affected by borderline personality disorder. The development of infant regulatory systems is influenced by early parenting experiences. These frontolimbic regulatory systems are also heavily implicated in normal parental responses to infant cues. These frontolimbic disturbances are also observed in studies of borderline personality disorder; a disorder associated with poor emotional regulation, early trauma and disturbed parenting. While the current literature is limited to animal models of abnormal care giving, existing disorders associated with deficits in regulatory capacity and abnormal frontolimbic functioning may yet provide a human model of the neurobiology of parenting disturbance.

  18. Taxonomic and trait based recolonization dynamics of a riverine fish assemblage following a large scale human mediated disturbance: the red mud disaster in Hungary

    Directory of Open Access Journals (Sweden)

    Tibor Eros

    2015-12-01

    Full Text Available We examined the recovery of a fish assemblage following the catastrophic spill of highly alkaline (pH~13 red sludge into a lowland river (i to characterize taxonomic and trait based colonization of fishes in the river in the first three years of the recovery, and (ii to determine which structural and trait based variables best predicted colonization. Species richness showed comparable values to pre-disturbance state less than one year after the spill. We found only moderate changes in the dominance of the most abundant species between pre- and post-disturbance periods, and consistent changes in the relative abundance of some rare species during the post-disturbance period. Frequency of occurrence (% of the fishes in the watershed, and their relative abundance (% proved to be the most important predictor variables in colonization, whereas trait based variables had a less important role. Our study about one of the largest scale and most serious documented fish kill shows that both taxonomic and trait based structure of fish assemblages can regenerate remarkable fast in a modified river and also shows that unfortunate chemical spills provide insights into the assembly of stream fish assemblages.

  19. Sudden Ionospheric Disturbances (SID)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sudden ionospheric disturbances (SID) are caused by solar flare enhanced X-rays in the 1 to 10 angstrom range. Solar flares can produce large increases of ionization...

  20. Depression Disturbs Germany

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The suicide of Robert Enke,the goalkeeper of the Germany national football team who had battled depression for years,stunned the country and cast depression into the national spotlight as a disturbing disease.

  1. Analysis of disturbance

    International Nuclear Information System (INIS)

    Ciala-Wein, H.; Stegmaier, W.

    1977-12-01

    The analyses of disturbances are the supposition for the development of processes and plants. They are very important in the field of nuclear testing plants. In this report are described the possibilities to register the circumstances of the disturbance in a pilot waste processing facility and a computer programme to interpret them. This is a first scheme and it will be necessary to complete it. (orig.) [de

  2. Disturbance phenomena in VLF standard radio wave observation

    International Nuclear Information System (INIS)

    Muraoka, Yoshikazu

    1977-01-01

    Storm aftereffect, i.e. the phase disturbance after initiation of a magnetic storm has been revealed in the observation of VLF standard radio waves. In VLF long distance propagation at middle latitudes (L - 3), the phase disturbance for several days after the initiation of a magnetic storm is due to electron fall from the radiation belt. This has been confirmed by the comparison with electron flux detected by an artificial satellite. The correlations between VLF phase disturbance and magnetism activity or ionosphere absorption are described. The relation between winter anomaly and phase disturbance is also discussed. (Mori, K.)

  3. Comparison of human and electronic observation for the measurement of compliance with hand hygiene.

    Science.gov (United States)

    Filho, Miguel Almeida O; Marra, Alexandre R; Magnus, Thyago Pereira; Rodrigues, Rodrigo Dias; Prado, Marcelo; de Souza Santini, Tales Roberto; da Silva Victor, Elivane; Ishibe, Eder Issao; Pavão Dos Santos, Oscar Fernando; Edmond, Michael B

    2014-11-01

    Monitoring of hand hygiene is an important part of the improvement of hospital quality indicators. This study was prospectively performed over a 14-week (electronic observer) period from December 3, 2013-March 9, 2014, to evaluate hand hygiene compliance in an adult step-down unit. We compared electronic handwash counters with the application of radiofrequency identification (RFID - ZigBee; i-Healthsys, São Carlos, Brazil) (electronic observer), which counts each activation of the alcohol gel dispenser to direct observation (human observer) using the iScrub application. For the overall time period of simultaneous electronic and human observation, we found that the electronic observer identified 414 hand hygiene episodes, whereas the human observers identified 448 episodes. Therefore, we found 92% (95% confidence interval [CI], 90%-95%) overall concordance (414/448), with an intraclass correlation coefficient of .87 (95% CI, 0.77-0.92). Our RFID (ZigBee) system showed good accuracy (92%) and is a useful method to monitor hand hygiene compliance. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  4. Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

    1976-01-01

    The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

  5. Earthing: Health Implications of Reconnecting the Human Body to the Earth's Surface Electrons

    International Nuclear Information System (INIS)

    Chevalier, G.; Chevalier, G.; Sinatra, S.T.; Oschman, J.L.; Sokal, K.; Sokal, P.

    2012-01-01

    Environmental medicine generally addresses environmental factors with a negative impact on human health. However, emerging scientific research has revealed a surprisingly positive and overlooked environmental factor on health: direct physical contact with the vast supply of electrons on the surface of the Earth. Modern lifestyle separates humans from such contact. The research suggests that this disconnect may be a major contributor to physiological dysfunction and un wellness. Reconnection with the Earth's electrons has been found to promote intriguing physiological changes and subjective reports of well-being. Earthing (or grounding) refers to the discovery of benefits including better sleep and reduced pain from walking barefoot outside or sitting, working, or sleeping indoors connected to conductive systems that transfer the Earth's electrons from the ground into the body. This paper reviews the earthing research and the potential of earthing as a simple and easily accessed global modality of significant clinical importance

  6. Diversity of extracellular vesicles in human ejaculates revealed by cryo-electron microscopy

    Directory of Open Access Journals (Sweden)

    Johanna L. Höög

    2015-11-01

    Full Text Available Human ejaculates contain extracellular vesicles (EVs, that to a large extent are considered to originate from the prostate gland, and are often denominated “prostasomes.” These EVs are important for human fertility, for example by promoting sperm motility and by inducing immune tolerance of the female immune system to the spermatozoa. So far, the EVs present in human ejaculate have not been studied in their native state, inside the seminal fluid without prior purification and isolation procedures. Using cryo-electron microscopy and tomography, we performed a comprehensive inventory of human ejaculate EVs. The sample was neither centrifuged, fixed, filtered or sectioned, nor were heavy metals added. Approximately 1,500 extracellular structures were imaged and categorized. The extracellular environment of human ejaculate was found to be diverse, with 5 major subcategories of EVs and 6 subcategories of extracellular membrane compartments, including lamellar bodies. Furthermore, 3 morphological features, including electron density, double membrane bilayers and coated surface, are described in all subcategories. This study reveals that the extracellular environment in human ejaculate is multifaceted. Several novel morphological EV subcategories are identified and clues to their cellular origin may be found in their morphology. This inventory is therefore important for developing future experimental approaches, and to interpret previously published data to understand the role of EVs for human male fertility.

  7. Genetic structure of brown pelicans (Pelecanus occidentalis in the northern Gulf of Mexico in the context of human management and disturbance.

    Directory of Open Access Journals (Sweden)

    Brock Geary

    Full Text Available Environmental disturbances, both natural and anthropogenic, have the capacity to substantially impact animal behavior and abundance, which can in turn influence patterns of genetic diversity and gene flow. However, little empirical information is available on the nature and degree of such changes due to the relative rarity of longitudinal genetic sampling of wild populations at appropriate intervals. Addressing this knowledge gap is therefore of interest to evolutionary biologists, policy makers, and managers. In the past half century, populations of the brown pelican (Pelecanus occidentalis in the southeastern United States have been exposed to regional extirpations, translocations, colony losses, and oil spills, but potential impacts on genetic diversity and population structure remain unknown. To investigate the cumulative impacts of recent disturbances and management actions, we analyzed seven microsatellite loci using genetic samples collected from 540 nestlings across twelve pelican colonies from two time periods, corresponding to before (n = 305 and after (n = 235 the 2010 Deepwater Horizon oil spill. Pre-2010 populations in Texas were significantly differentiated from Louisiana, Alabama, and Florida populations to the east, with reintroduced populations in southeastern Louisiana having less genetic diversity than sites in Texas, consistent with a recent bottleneck. In contrast, there was no evidence of a geographic component to genetic structure among colonies sampled after the spill, consistent with increased dispersal among sites following the event. This pattern may be associated with reduced philopatry in response to colony abandonment in the areas most heavily impacted by the Deepwater Horizon event, though other factors (e.g., rehabilitation and translocation of oiled birds or colony loss due to erosion and tropical storms were likely also involved. Future monitoring is necessary to determine if bottlenecks and loss of genetic

  8. Disturbance recording system

    International Nuclear Information System (INIS)

    Chandra, A.K.; Deshpande, S.V.; Mayya, A.; Vaidya, U.W.; Premraj, M.K.; Patil, N.B.

    1994-01-01

    A computerized system for disturbance monitoring, recording and display has been developed for use in nuclear power plants and is versatile enough to be used where ever a large number of parameters need to be recorded, e.g. conventional power plants, chemical industry etc. The Disturbance Recording System (DRS) has been designed to continuously monitor a process plant and record crucial parameters. The DRS provides a centralized facility to monitor and continuously record 64 process parameters scanned every 1 sec for 5 days. The system also provides facility for storage of 64 parameters scanned every 200 msec during 2 minutes prior to and 3 minutes after a disturbance. In addition the system can initiate, on demand, the recording of 8 parameters at a fast rate of every 5 msec for a period of 5 sec. and thus act as a visicorder. All this data is recorded in non-volatile memory and can be displayed, printed/plotted and used for subsequent analysis. Since data can be stored densely on floppy disks, the volume of space required for archival storage is also low. As a disturbance recorder, the DRS allows the operator to view the state of the plant prior to occurrence of the disturbance and helps in identifying the root cause. (author). 10 refs., 7 figs

  9. The reactivity of plant, murine and human genome to electron beam irradiation

    International Nuclear Information System (INIS)

    Gavrila, L.; Usurelu, D.; Radu, I.; Timus, D.

    2005-01-01

    A broad spectrum of chromosomal rearrangements is described in plants (Allium cepa), mouse (Mus musculus domestics) and in humans (Homo sapiens sapiens), following in vivo and in vitro beta irradiation. Irradiations were performed at EAL, using a 2.998 GHz traveling-wave electron accelerator. The primary effect of electron beam irradiation is chromosomal breakage followed up by a variety of chromosomal rearrangements i.e. chromosomal aberrations represented mainly by chromatid gaps, deletions, ring chromosomes, dicentrics, translocations, complex chromosomal interchanges, acentric fragments and double minutes (DM). The clastogenic effects were associated in some instances with cell sterilization (i.e. cell death)

  10. Study and structural and chemical characterization of human dental smalt by electron microscopy

    International Nuclear Information System (INIS)

    Belio R, I.A.; Reyes G, J.

    1998-01-01

    The study of human dental smalt has been subject to investigation for this methods with electron microscopy, electron diffraction, X-ray diffraction and image simulation programs have been used with the purpose to determine its chemical and structural characteristics of the organic and inorganic materials. This work has been held mainly for the characterization of hydroxyapatite (Ca) 10 (PO 4 ) 6 (OH 4 ) 2 , inorganic material which conforms the dental smalt in 97%, so observing its structural unity which is composed by the prisms and these by crystals and atoms. It was subsequently initiated the study of the organic material, with is precursor of itself. (Author)

  11. Sleep disturbances in Parkinsonism.

    Science.gov (United States)

    Askenasy, J J M

    2003-02-01

    The present article is meant to suggest an approach to the guidelines for the therapy of sleep disturbances in Parkinson's Disease (PD) patients.The factors affecting the quality of life in PD patients are depression, sleep disturbances and dependence. A large review of the literature on sleep disturbances in PD patients, provided the basis for the following classification of the sleep-arousal disturbances in PD patients. We suggest a model based on 3 steps in the treatment of sleep disturbances in PD patients. This model allowing the patient, the spouse or the caregiver a quiet sleep at night, may postpone the retirement and the institutionalization of the PD patient. I. Correct diagnosis of sleep disorders based on detailed anamnesis of the patient and of the spouse or of the caregiver. One week recording on a symptom diary (log) by the patient or the caregiver. Correct diagnosis of sleep disorders co morbidities. Selection of the most appropriate sleep test among: polysomnography (PSG), multiple sleep latency test (MSLT), multiple wake latency test (MWLT), Epworth Sleepiness Scale, actigraphy or video-PSG. II. The nonspecific therapeutic approach consists in: a) Checking the sleep effect on motor performance, is it beneficial, worse or neutral. b) Psycho-physical assistance. c) Dopaminergic adjustment is necessary owing to the progression of the nigrostriatal degeneration and the increased sensitivity of the terminals, which alter the normal modulator mechanisms of the motor centers in PD patients. Among the many neurotransmitters of the nigro-striatal pathway one can distinguish two with a major influence on REM and NonREM sleep. REM sleep corresponds to an increased cholinergic receptor activity and a decreased dopaminergic activity. This is the reason why REM sleep deprivation by suppressing cholinergic receptor activity ameliorates PD motor symptoms. L-Dopa and its agonists by suppressing cholinergic receptors suppress REM sleep. The permanent adjustment

  12. Estimation and harvesting of human heat power for wearable electronic devices

    International Nuclear Information System (INIS)

    Dziurdzia, P; Brzozowski, I; Bratek, P; Gelmuda, W; Kos, A

    2016-01-01

    The paper deals with the issue of self-powered wearable electronic devices that are capable of harvesting free available energy dissipated by the user in the form of human heat. The free energy source is intended to be used as a secondary power source supporting primary battery in a sensor bracelet. The main scope of the article is a presentation of the concept for a measuring setup used to quantitative estimation of heat power sources in different locations over the human body area. The crucial role in the measurements of the human heat plays a thermoelectric module working in the open circuit mode. The results obtained during practical tests are confronted with the requirements of the dedicated thermoelectric generator. A prototype design of a human warmth energy harvester with an ultra-low power DC-DC converter based on the LTC3108 circuit is analysed

  13. Soft Electronics Enabled Ergonomic Human-Computer Interaction for Swallowing Training

    Science.gov (United States)

    Lee, Yongkuk; Nicholls, Benjamin; Sup Lee, Dong; Chen, Yanfei; Chun, Youngjae; Siang Ang, Chee; Yeo, Woon-Hong

    2017-04-01

    We introduce a skin-friendly electronic system that enables human-computer interaction (HCI) for swallowing training in dysphagia rehabilitation. For an ergonomic HCI, we utilize a soft, highly compliant (“skin-like”) electrode, which addresses critical issues of an existing rigid and planar electrode combined with a problematic conductive electrolyte and adhesive pad. The skin-like electrode offers a highly conformal, user-comfortable interaction with the skin for long-term wearable, high-fidelity recording of swallowing electromyograms on the chin. Mechanics modeling and experimental quantification captures the ultra-elastic mechanical characteristics of an open mesh microstructured sensor, conjugated with an elastomeric membrane. Systematic in vivo studies investigate the functionality of the soft electronics for HCI-enabled swallowing training, which includes the application of a biofeedback system to detect swallowing behavior. The collection of results demonstrates clinical feasibility of the ergonomic electronics in HCI-driven rehabilitation for patients with swallowing disorders.

  14. Nutritional disturbances by adolescent

    OpenAIRE

    Stassart, Martine

    2011-01-01

    The nutritional disturbances are frequent by adolescents. That is a psychological defense against dependance toward the mother but also a middle to remain in a childish position i.e. either as a fat baby - in the fall of obesity- or as the ideal pre- or bisexual great child - in the case of anorexia.

  15. Materials and optimized designs for human-machine interfaces via epidermal electronics.

    Science.gov (United States)

    Jeong, Jae-Woong; Yeo, Woon-Hong; Akhtar, Aadeel; Norton, James J S; Kwack, Young-Jin; Li, Shuo; Jung, Sung-Young; Su, Yewang; Lee, Woosik; Xia, Jing; Cheng, Huanyu; Huang, Yonggang; Choi, Woon-Seop; Bretl, Timothy; Rogers, John A

    2013-12-17

    Thin, soft, and elastic electronics with physical properties well matched to the epidermis can be conformally and robustly integrated with the skin. Materials and optimized designs for such devices are presented for surface electromyography (sEMG). The findings enable sEMG from wide ranging areas of the body. The measurements have quality sufficient for advanced forms of human-machine interface. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Analysis of the electronic structure of human hemoglobin from soft X-ray emission

    International Nuclear Information System (INIS)

    Soldatov, A.V.; Kravtsova, A.N.; Fedorovich, E.N.; Ankudinov, A.; Moewes, A.; Kurmaev, E.Z.

    2005-01-01

    We present X-ray emission spectra (XES) of human hemoglobin excited near the iron L 2,3 threshold and the nitrogen and carbon K-edges. The experiment is compared with our calculations of the corresponding spectra and gives good agreement. We find that the Fe L 3 emission is affected by the nearest nitrogen atoms located in the heme plane around the central iron atom. The distribution of the partial electronic densities of states of hemoglobin is determined

  17. Humanized Mouse Model of Skin Inflammation Is Characterized by Disturbed Keratinocyte Differentiation and Influx of IL-17A Producing T Cells

    Science.gov (United States)

    de Oliveira, Vivian L.; Keijsers, Romy R. M. C.; van de Kerkhof, Peter C. M.; Seyger, Marieke M. B.; Fasse, Esther; Svensson, Lars; Latta, Markus; Norsgaard, Hanne; Labuda, Tord; Hupkens, Pieter; van Erp, Piet E. J.; Joosten, Irma; Koenen, Hans J. P. M.

    2012-01-01

    Humanized mouse models offer a challenging possibility to study human cell function in vivo. In the huPBL-SCID-huSkin allograft model human skin is transplanted onto immunodeficient mice and allowed to heal. Thereafter allogeneic human peripheral blood mononuclear cells are infused intra peritoneally to induce T cell mediated inflammation and microvessel destruction of the human skin. This model has great potential for in vivo study of human immune cells in (skin) inflammatory processes and for preclinical screening of systemically administered immunomodulating agents. Here we studied the inflammatory skin response of human keratinocytes and human T cells and the concomitant systemic human T cell response. As new findings in the inflamed human skin of the huPBL-SCID-huSkin model we here identified: 1. Parameters of dermal pathology that enable precise quantification of the local skin inflammatory response exemplified by acanthosis, increased expression of human β-defensin-2, Elafin, K16, Ki67 and reduced expression of K10 by microscopy and immunohistochemistry. 2. Induction of human cytokines and chemokines using quantitative real-time PCR. 3. Influx of inflammation associated IL-17A-producing human CD4+ and CD8+ T cells as well as immunoregulatory CD4+Foxp3+ cells using immunohistochemistry and -fluorescence, suggesting that active immune regulation is taking place locally in the inflamed skin. 4. Systemic responses that revealed activated and proliferating human CD4+ and CD8+ T cells that acquired homing marker expression of CD62L and CLA. Finally, we demonstrated the value of the newly identified parameters by showing significant changes upon systemic treatment with the T cell inhibitory agents cyclosporine-A and rapamycin. In summary, here we equipped the huPBL-SCID-huSkin humanized mouse model with relevant tools not only to quantify the inflammatory dermal response, but also to monitor the peripheral immune status. This combined approach will gain our

  18. Sleep disturbance associated factors in menopausal women

    Directory of Open Access Journals (Sweden)

    Hamid Haghani

    2011-09-01

    Full Text Available Background: Sleep is necessary in life and approximately 1/3 of human life is devoted to sleep. One of the most common problems in menopausal women is sleep disturbance. The aim of this study was to determine frequency of sleep disorders and its related factors in 50 – 60 years old women Methods: A cross-sectional, descriptive study was conducted on 200 eligible women who referred to selected health centers of Tehran University of Medical Sciences (TUMS. Demographic form, ten-point slide to review sexual satisfaction and Pittsburg Sleep Quality Index Questioner (PSQI were used for data collection. Data was analyzed using ANOVA, t-test, and Pearson correlation tests.Results: The mean age of women was 53.6±3.6 year, menopause age 47.8±4, number of children 4.76±2 and partner age was 57.99±6.6. 34.5% of women were satisfied from their sexual relationship and their score was 8-10. Rate of sleep disturbances in this group was about 70%. The results showed that between four variables: economical status, occupation, partner occupation and educational status were significantly associated with sleep disturbance (P=0.002. There was not significant difference between other demographic information and sleep disturbance.Conclusion: The results show high prevalence of sleep disturbance symptoms among menopausal women. According to the relationship between some personal characters and sleep disturbance, health care providers need to consider these variables.

  19. Concepts and Challenges in Disturbance Hydrology

    Science.gov (United States)

    Ebel, B. A.; Mirus, B. B.

    2016-12-01

    Landscape disturbances are increasing, often promoted and enhanced by climate shifts and human activities. Insect infestations, wildfires, earthquakes, urban development, forest harvest, mineral and petroleum resource extraction, and hurricanes are common landscape disturbances that can have profound hydrologic consequences. These cause relatively abrupt changes in the landscape, which alter local processes on plots and hillslopes in addition to coarser-scale processes across watersheds through cross-scale interactions. Shifts in soil properties and cover of vegetation and leaf litter change the water storage or buffering capacity as well as the hydrologic functional connectivity across multiple scales. These changes increase the risk of catastrophic flooding, erosion, and mass movements that degrade water resources, ecosystem services, and protection from hydrologically driven natural hazards. Although it is imperative that we understand the hydrologic effects of these disturbances, several major barriers exist. Four challenges are: (i) overlapping disturbances in space and time with unknown recovery trajectories, (ii) a paucity of long-term recovery records (>5 years duration), (iii) inefficacy of traditional modeling and parameterization approaches, and (iv) lack of pre-disturbance characterization. Examples of these challenges will be presented along with proposed opportunities for improved mechanistic understanding of processes and thresholds in disturbance hydrology.

  20. From "Forest Fires" and "Hunting" to Disturbing "Habitats" and "Food Chains": Do Young Children Come Up with Any Ecological Interpretations of Human Interventions within a Forest?

    Science.gov (United States)

    Ergazaki, Marida; Andriotou, Eirini

    2010-01-01

    This study aims at highlighting young children's reasoning about human interventions within a forest ecosystem. Our focus is particularly set on whether preschoolers are able to come up with any basic ecological interpretations of human actions upon forest plants or animals and how. Conducting individual, semi-structured interviews with 70…

  1. Electron density values of various human tissues: in vitro Compton scatter measurements and calculated ranges

    International Nuclear Information System (INIS)

    Shrimpton, P.C.

    1981-01-01

    Accurate direct measurements of electron density have been performed on specimens from 10 different tissue types of the human body, representing the major organs, using a Compton scatter technique. As a supplement to these experimental values, calculations have been carried out to determine the electron densities expected for these tissue types. The densities observed are in good agreement with the broad ranges deduced from the basic data previously published. The results of both the in vitro sample measurements and the approximate calculations indicate that the electron density of most normal healthy soft tissue can be expected to fall within the fairly restricted range of +- 5% around 3.4 X 10 23 electrons per cm 3 . The obvious exception to this generalisation is the result for lung tissue, which falls considerably below this range owing to the high air content inherent in its construction. In view of such an overall limited variation with little difference between tissues, it would appear that electron density alone is likely to be a rather poor clinical parameter for tissue analysis, with high accuracy and precision being essential in any in vivo Compton measurements for imaging or diagnosis on specific organs. (author)

  2. Identification and classification of human cytomegalovirus capsids in textured electron micrographs using deformed template matching

    Directory of Open Access Journals (Sweden)

    Söderberg-Nauclér Cecilia

    2006-08-01

    Full Text Available Abstract Background Characterization of the structural morphology of virus particles in electron micrographs is a complex task, but desirable in connection with investigation of the maturation process and detection of changes in viral particle morphology in response to the effect of a mutation or antiviral drugs being applied. Therefore, we have here developed a procedure for describing and classifying virus particle forms in electron micrographs, based on determination of the invariant characteristics of the projection of a given virus structure. The template for the virus particle is created on the basis of information obtained from a small training set of electron micrographs and is then employed to classify and quantify similar structures of interest in an unlimited number of electron micrographs by a process of correlation. Results Practical application of the method is demonstrated by the ability to locate three diverse classes of virus particles in transmission electron micrographs of fibroblasts infected with human cytomegalovirus. These results show that fast screening of the total number of viral structures at different stages of maturation in a large set of electron micrographs, a task that is otherwise both time-consuming and tedious for the expert, can be accomplished rapidly and reliably with our automated procedure. Using linear deformation analysis, this novel algorithm described here can handle capsid variations such as ellipticity and furthermore allows evaluation of properties such as the size and orientation of a virus particle. Conclusion Our methodological procedure represents a promising objective tool for comparative studies of the intracellular assembly processes of virus particles using electron microscopy in combination with our digitized image analysis tool. An automated method for sorting and classifying virus particles at different stages of maturation will enable us to quantify virus production in all stages of the

  3. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    International Nuclear Information System (INIS)

    Wang Wen; Hu Liqin; Cheng Mengyun; Long Pengcheng

    2015-01-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. (authors)

  4. Ionospheric irregularities in periods of meteorological disturbances

    Science.gov (United States)

    Borchevkina, O. P.; Karpov, I. V.

    2017-09-01

    The results of observations of the total electron content (TEC) in periods of storm disturbances of meteorological situation are presented in the paper. The observational results have shown that a passage of a meteorological storm is accompanied by a substantial decrease in values of TEC and critical frequencies of the ionospheric F2 region. The decreases in values of these ionospheric parameters reach 50% and up to 30% in TEC and critical frequency of the F2 layer, respectively, as compared to meteorologically quiet days. Based on qualitative analysis, it is found that the processes related to formation of local regions of thermospheric heating due to a dissipation of AGW coming into the upper atmosphere from the region of the meteorological disturbance in the lower atmosphere are a possible cause of these ionospheric disturbances.

  5. Fine-Scale Evaluation of Giant Panda Habitats and Countermeasures against the Future Impacts of Climate Change and Human Disturbance (2015–2050: A Case Study in Ya’an, China

    Directory of Open Access Journals (Sweden)

    Jing Zhen

    2018-04-01

    Full Text Available The accelerating impact of climate change on giant panda (Ailuropoda melanoleuca habitats have become an international research topic. Recently, many studies have also focused on medium-sized mountain ranges or entire giant panda habitats to predict how habitats will change as the climate warms, but few say in detail what to do or where to focus efforts. To fill this gap, this paper presents a new method to take comprehensive, fine-scale evaluations incorporating climate change, human disturbance, and current conservation networks and translate them into practical countermeasures in order to help decision-makers set priority regions for conservation. This study looked at the core area of the Sichuan Giant Panda Sanctuaries United Nations Educational, Scientific and Cultural Organisation (UNESCO World Natural Heritage site, namely Ya’an Prefecture, as a case study. The research employs the Maximum Entropy (MaxEnt modeling algorithm to analyze how climate change will affect the habitats by 2050 under two scenarios: only considering the influence of climate change, and thinking about the coupled influence of climate change and human disturbance together. The results showed the following: (1 only considering climate change, the overall habitat that can be used by giant pandas in this region will increase, which differs from most of the previous results showing a decrease; (2 the new suitable habitat will shift westward, northward and eastward in this region; (3 conversely, the suitable habitat will be significantly reduced (about 58.56% and fragmentized when taking into account human disturbance factors; (4 at present, the three small nature reserves are far from each other and cannot cover the present habitat well nor protect the potentially suitable habitats. Based on the comprehensive analysis of habitat shifts and our two field investigations, we suggest two regions that can be expanded into the conservation network to contain more potentially

  6. Exposure to perfluorononanoic acid combined with a low-dose mixture of 14 human-relevant compounds disturbs energy/lipid homeostasis in rats

    DEFF Research Database (Denmark)

    Skov, Kasper; Kongsbak, Kristine Grønning; Hadrup, Niels

    2015-01-01

    , whereas effects on lipid metabolism in the liver were mainly driven by PFNA. This study verifies that a chemical mixture given at high-end human exposure levels can affect lipid homeostasis and that the combined use of metabolomics and transcriptomics can provide complimentary information allowing......Humans are constantly exposed to a significant number of compounds and many are readily detected in human body fluids. Worryingly, several of these compounds are either suspected to be, or have already been shown to be harmful to humans either individually or in combination. However, the potential...... consequences of low-dose exposure to complex mixtures remain poorly understood. We have profiled the effects on rat blood plasma and liver homeostasis using metabolomics and transcriptomics following 2-week exposure to either a mixture of 14 common chemicals (Mix), perfluorononanoic acid (PFNA) at low (0...

  7. Postoperative circadian disturbances

    DEFF Research Database (Denmark)

    Gögenur, Ismail

    2010-01-01

    ) in urine the first night after both minor and major surgery. This delay after major surgery was correlated to the duration of surgery. The amplitude in the melatonin rhythm was unchanged the first night but increased in the second night after major surgery. The amplitude in AMT6s was reduced the first...... night after minimally invasive surgery. The core body temperature rhythm was disturbed after both major and minor surgery. There was a change in the sleep wake cycle with a significantly increased duration of REM-sleep in the day and evening time after major surgery compared with preoperatively....... There was also a shift in the autonomic nervous balance after major surgery with a significantly increased number of myocardial ischaemic episodes during the nighttime period. The circadian activity rhythm was also disturbed after both minor and major surgery. The daytime AMT6s excretion in urine after major...

  8. 300 Area Disturbance Report

    Energy Technology Data Exchange (ETDEWEB)

    LL Hale; MK Wright; NA Cadoret

    1999-01-07

    The objective of this study was to define areas of previous disturbance in the 300 Area of the U.S. Department of Energy (DOE) Hanford Site to eliminate these areas from the cultural resource review process, reduce cultural resource monitoring costs, and allow cultural resource specialists to focus on areas where subsurface disturbance is minimal or nonexistent. Research into available sources suggests that impacts from excavations have been significant wherever the following construction activities have occurred: building basements and pits, waste ponds, burial grounds, trenches, installation of subsurface pipelines, power poles, water hydrants, and well construction. Beyond the areas just mentioned, substrates in the' 300 Area consist of a complex, multidimen- sional mosaic composed of undisturbed stratigraphy, backfill, and disturbed sediments; Four Geographic Information System (GIS) maps were created to display known areas of disturbance in the 300 Area. These maps contain information gleaned from a variety of sources, but the primary sources include the Hanford GIS database system, engineer drawings, and historic maps. In addition to these maps, several assumptions can be made about areas of disturbance in the 300 Area as a result of this study: o o Buried pipelines are not always located where they are mapped. As a result, cultural resource monitors or specialists should not depend on maps depicting subsurface pipelines for accurate locations of previous disturbance. Temporary roads built in the early 1940s were placed on layers of sand and gravel 8 to 12 in. thick. Given this information, it is likely that substrates beneath these early roads are only minimally disturbed. Building foundations ranged from concrete slabs no more than 6 to 8 in. thick to deeply excavated pits and basements. Buildings constructed with slab foundations are more numerous than may be expected, and minimally disturbed substrates may be expected in these locations. Historic

  9. Rehabilitation of disturbed land

    Energy Technology Data Exchange (ETDEWEB)

    Bell, L.C. [Australian Centre for Minesite Rehabilitation Research, Kenmore, Qld. (Australia)

    1996-12-31

    This chapter discusses the objectives of rehabilitation of lands in Australian disturbed by mining. It gives advice on rehabilitation planning and outlines the factors influencing post-mining land use and rehabilitation strategies, including climate, topography, hydrology, properties of soils, overburden and mineral processing wastes, flora and fauna and social considerations. Finally, the key elements of a rehabilitation plan are discussed, namely: landscape reconstruction; selective handling of overburden; and establishment and maintenance of a vegetative cover. 12 figs., 1 tab.

  10. Mechanically Compliant Electronic Materials for Wearable Photovoltaics and Human-Machine Interfaces

    Science.gov (United States)

    O'Connor, Timothy Francis, III

    Applications of stretchable electronic materials for human-machine interfaces are described herein. Intrinsically stretchable organic conjugated polymers and stretchable electronic composites were used to develop stretchable organic photovoltaics (OPVs), mechanically robust wearable OPVs, and human-machine interfaces for gesture recognition, American Sign Language Translation, haptic control of robots, and touch emulation for virtual reality, augmented reality, and the transmission of touch. The stretchable and wearable OPVs comprise active layers of poly-3-alkylthiophene:phenyl-C61-butyric acid methyl ester (P3AT:PCBM) and transparent conductive electrodes of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and devices could only be fabricated through a deep understanding of the connection between molecular structure and the co-engineering of electronic performance with mechanical resilience. The talk concludes with the use of composite piezoresistive sensors two smart glove prototypes. The first integrates stretchable strain sensors comprising a carbon-elastomer composite, a wearable microcontroller, low energy Bluetooth, and a 6-axis accelerometer/gyroscope to construct a fully functional gesture recognition glove capable of wirelessly translating American Sign Language to text on a cell phone screen. The second creates a system for the haptic control of a 3D printed robot arm, as well as the transmission of touch and temperature information.

  11. Energy Harvesting from the Animal/Human Body for Self-Powered Electronics.

    Science.gov (United States)

    Dagdeviren, Canan; Li, Zhou; Wang, Zhong Lin

    2017-06-21

    Living subjects (i.e., humans and animals) have abundant sources of energy in chemical, thermal, and mechanical forms. The use of these energies presents a viable way to overcome the battery capacity limitation that constrains the long-term operation of wearable/implantable devices. The intersection of novel materials and fabrication techniques offers boundless possibilities for the benefit of human health and well-being via various types of energy harvesters. This review summarizes the existing approaches that have been demonstrated to harvest energy from the bodies of living subjects for self-powered electronics. We present material choices, device layouts, and operation principles of these energy harvesters with a focus on in vivo applications. We discuss a broad range of energy harvesters placed in or on various body parts of human and animal models. We conclude with an outlook of future research in which the integration of various energy harvesters with advanced electronics can provide a new platform for the development of novel technologies for disease diagnostics, treatment, and prevention.

  12. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  13. Climate change and forest disturbances

    Science.gov (United States)

    Virginia H. Dale; Linda A. Joyce; Steve McNulty; Ronald P. Neilson; Matthew P. Ayres; Michael D. Flannigan; Paul J. Hanson; Lloyd C. Irland; Ariel E. Lugo; Chris J. Peterson; Daniel Simberloff; Frederick J. Swanson; Brian J. Stocks; Michael Wotton

    2001-01-01

    This article examines how eight disturbances influence forest structure, composition, and function, and how climate change may influence the severity, frequency, and magnitude of disturbances to forests. We focus on examples from the United States, although these influences occur worldwide. We also consider options for coping with disturbance under changing climate....

  14. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  15. Handling process disturbances in petroleum production

    Energy Technology Data Exchange (ETDEWEB)

    Sten, T; Bodsberg, L; Ingstad, O; Ulleberg, T

    1988-06-01

    Factors of importance in successful handling of major disturbances and crisis situations in petroleum production are discussed. Case studies based on interviews, questionnaires and systematic observations have been undertaken to identify critical factors in human computer design, in operator competence and attitudes and in work organization. It is shown that certain features of the humancomputer interaction become critical when serious disturbances are encountered. Likewise focusing on requirements during disturbances in particular has highlighted some new aspects of operator competence and of the work organization. The results are considered to be useful input to safety management in petroleum process plants, in formation of design specifications and in identifying need for further research regarding safety in offshore production.

  16. Identification and Characterization of Disturbed Alder Sites on Elmendorf Air Force Base, Alaska

    National Research Council Canada - National Science Library

    Tande, Gerald

    2001-01-01

    Vegetation data were collected to identify and characterize disturbed alder (Alnus spp.) areas and provide an ArcView GIS layer for specific sites of alder encroachment likely due to human disturbance...

  17. Electron Paramagnetic Resonance Spectrometry and Imaging in Melanomas: Comparison between Pigmented and Nonpigmented Human Malignant Melanomas

    Directory of Open Access Journals (Sweden)

    Quentin Godechal

    2013-06-01

    Full Text Available It has been known for a long time that the melanin pigments present in normal skin, hair, and most of malignant melanomas can be detected by electron paramagnetic resonance (EPR spectrometry. In this study, we used EPR imaging as a tool to map the concentration of melanin inside ex vivo human pigmented and nonpigmented melanomas and correlated this cartography with anatomopathology. We obtained accurate mappings of the melanin inside pigmented human melanoma samples. The signal intensity observed on the EPR images correlated with the concentration of melanin within the tumors, visible on the histologic sections. In contrast, no EPR signal coming from melanin was observed from nonpigmented melanomas, therefore demonstrating the absence of EPR-detectable pigments inside these particular cases of skin cancer and the importance of pigmentation for further EPR imaging studies on melanoma.

  18. Disturbance by optimal discrimination

    Science.gov (United States)

    Kawakubo, Ryûitirô; Koike, Tatsuhiko

    2018-03-01

    We discuss the disturbance by measurements which unambiguously discriminate between given candidate states. We prove that such an optimal measurement necessarily changes distinguishable states indistinguishable when the inconclusive outcome is obtained. The result was previously shown by Chefles [Phys. Lett. A 239, 339 (1998), 10.1016/S0375-9601(98)00064-4] under restrictions on the class of quantum measurements and on the definition of optimality. Our theorems remove these restrictions and are also applicable to infinitely many candidate states. Combining with our previous results, one can obtain concrete mathematical conditions for the resulting states. The method may have a wide variety of applications in contexts other than state discrimination.

  19. Sleep Disturbances in Neurodevelopmental Disorders.

    Science.gov (United States)

    Robinson-Shelton, Althea; Malow, Beth A

    2016-01-01

    Sleep disturbances are extremely prevalent in children with neurodevelopmental disorders compared to typically developing children. The diagnostic criteria for many neurodevelopmental disorders include sleep disturbances. Sleep disturbance in this population is often multifactorial and caused by the interplay of genetic, neurobiological and environmental overlap. These disturbances often present either as insomnia or hypersomnia. Different sleep disorders present with these complaints and based on the clinical history and findings from diagnostic tests, an appropriate diagnosis can be made. This review aims to provide an overview of causes, diagnosis, and treatment of sleep disturbances in neurodevelopmental disorders that present primarily with symptoms of hypersomnia and/or insomnia.

  20. Defining Disturbance for Microbial Ecology.

    Science.gov (United States)

    Plante, Craig J

    2017-08-01

    Disturbance can profoundly modify the structure of natural communities. However, microbial ecologists' concept of "disturbance" has often deviated from conventional practice. Definitions (or implicit usage) have frequently included climate change and other forms of chronic environmental stress, which contradict the macrobiologist's notion of disturbance as a discrete event that removes biomass. Physical constraints and disparate biological characteristics were compared to ask whether disturbances fundamentally differ in microbial and macroorganismal communities. A definition of "disturbance" for microbial ecologists is proposed that distinguishes from "stress" and other competing terms, and that is in accord with definitions accepted by plant and animal ecologists.

  1. Effects of the Use of Electronic Human Resource Management (EHRM Within Human Resource Management (HRM Functions at Universities

    Directory of Open Access Journals (Sweden)

    Chux Gervase Iwu

    2016-09-01

    Full Text Available This study set out to examine the effect of e-hrm systems in assisting human resource practitioners to execute their duties and responsibilities. In comparison to developed economies of the world, information technology adoption in sub-Saharan Africa has not been without certain glitches. Some of the factors that are responsible for these include poor need identification, sustainable funding, and insufficient skills. Besides these factors, there is also the issue of change management and users sticking to what they already know. Although, the above factors seem negative, there is strong evidence that information systems such as electronic human resource management present benefits to an organization. To achieve this, a dual research approach was utilized. Literature assisted immensely in both the development of the conceptual framework upon which the study hinged as well as in the development of the questionnaire items. The study also made use of an interview checklist to guide the participants. The findings reveal a mix of responses that indicate that while there are gains in adopting e-hrm systems, it is wiser to consider supporting resources as well as articulate the needs of the university better before any investment is made.

  2. Wettability modification of human tooth surface by water and UV and electron-beam radiation

    International Nuclear Information System (INIS)

    Tiznado-Orozco, Gaby E.; Reyes-Gasga, José; Elefterie, Florina; Beyens, Christophe; Maschke, Ulrich; Brès, Etienne F.

    2015-01-01

    The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time

  3. Accuracy and Consistency of Grass Pollen Identification by Human Analysts Using Electron Micrographs of Surface Ornamentation

    Directory of Open Access Journals (Sweden)

    Luke Mander

    2014-08-01

    Full Text Available Premise of the study: Humans frequently identify pollen grains at a taxonomic rank above species. Grass pollen is a classic case of this situation, which has led to the development of computational methods for identifying grass pollen species. This paper aims to provide context for these computational methods by quantifying the accuracy and consistency of human identification. Methods: We measured the ability of nine human analysts to identify 12 species of grass pollen using scanning electron microscopy images. These are the same images that were used in computational identifications. We have measured the coverage, accuracy, and consistency of each analyst, and investigated their ability to recognize duplicate images. Results: Coverage ranged from 87.5% to 100%. Mean identification accuracy ranged from 46.67% to 87.5%. The identification consistency of each analyst ranged from 32.5% to 87.5%, and each of the nine analysts produced considerably different identification schemes. The proportion of duplicate image pairs that were missed ranged from 6.25% to 58.33%. Discussion: The identification errors made by each analyst, which result in a decline in accuracy and consistency, are likely related to psychological factors such as the limited capacity of human memory, fatigue and boredom, recency effects, and positivity bias.

  4. Electron microscopy of CO/sub 2/-laser-induced effects in human fibrocartilage

    Energy Technology Data Exchange (ETDEWEB)

    Whipple, T.L.; Marotta, J.J.; May, T.C.; Caspari, R.B.; Meyers, J.F.

    1987-01-01

    Previous reports of effects of CO/sub 2/ laser energy on human fibrocartilage suggest thermal injury extends to a depth of approximately 70 microns from the target surface with power settings of 35 W and exposure times of 0.5 seconds. The present study was undertaken to look for more subtle evidence of thermal alteration of human fibrocartilage treated with CO/sub 2/ laser irradiation. Fifteen human menisci were irradiated at power settings of 10, 20, and 30 W with exposure times of 0.1 and 0.5 seconds. The specimens were immediately fixed and sectioned for electron microscopic examination. Loss of a normal cross banding, and marginal clarity of individual collagen fibers were observed in the extracellular matrix and were observed at distances up to 300 microns from the exposed tissue surface. In addition, cellular changes at similar tissue depth consisted of cell membrane invaginations, clumping of nuclear chromatin, breakdown of endoplasmic reticulum architecture, and loss of mitochondria and Golgi complexes from the cytoplasm were observed. This study demonstrates deeper penetration of a radiation that was previously appreciated by light microscopy in irradiated human fibrocartilage, although the implications with respect to contraside viability and healing potential of the tissue in vivo is not known.

  5. Wettability modification of human tooth surface by water and UV and electron-beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tiznado-Orozco, Gaby E., E-mail: gab0409@gmail.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Unidad Académica de Odontología, Universidad Autónoma de Nayarit, Edificio E7, Ciudad de la Cultura “Amado Nervo”, C.P. 63190 Tepic, Nayarit (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacan, México, D.F. (Mexico); Elefterie, Florina, E-mail: elefterie_florina@yahoo.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Beyens, Christophe, E-mail: christophe.beyens@ed.univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Maschke, Ulrich, E-mail: Ulrich.Maschke@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Brès, Etienne F., E-mail: etienne.bres@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France)

    2015-12-01

    The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time.

  6. Electronic cigarette liquid increases inflammation and virus infection in primary human airway epithelial cells.

    Science.gov (United States)

    Wu, Qun; Jiang, Di; Minor, Maisha; Chu, Hong Wei

    2014-01-01

    The use of electronic cigarettes (e-cigarettes) is rapidly increasing in the United States, especially among young people since e-cigarettes have been perceived as a safer alternative to conventional tobacco cigarettes. However, the scientific evidence regarding the human health effects of e-cigarettes on the lung is extremely limited. The major goal of our current study is to determine if e-cigarette use alters human young subject airway epithelial functions such as inflammatory response and innate immune defense against respiratory viral (i.e., human rhinovirus, HRV) infection. We examined the effects of e-cigarette liquid (e-liquid) on pro-inflammatory cytokine (e.g., IL-6) production, HRV infection and host defense molecules (e.g., short palate, lung, and nasal epithelium clone 1, SPLUNC1) in primary human airway epithelial cells from young healthy non-smokers. Additionally, we examined the role of SPLUNC1 in lung defense against HRV infection using a SPLUNC1 knockout mouse model. We found that nicotine-free e-liquid promoted IL-6 production and HRV infection. Addition of nicotine into e-liquid further amplified the effects of nicotine-free e-liquid. Moreover, SPLUNC1 deficiency in mice significantly increased lung HRV loads. E-liquid inhibited SPLUNC1 expression in primary human airway epithelial cells. These findings strongly suggest the deleterious health effects of e-cigarettes in the airways of young people. Our data will guide future studies to evaluate the impact of e-cigarettes on lung health in human populations, and help inform the public about potential health risks of e-cigarettes.

  7. Electronic cigarette liquid increases inflammation and virus infection in primary human airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Qun Wu

    Full Text Available The use of electronic cigarettes (e-cigarettes is rapidly increasing in the United States, especially among young people since e-cigarettes have been perceived as a safer alternative to conventional tobacco cigarettes. However, the scientific evidence regarding the human health effects of e-cigarettes on the lung is extremely limited. The major goal of our current study is to determine if e-cigarette use alters human young subject airway epithelial functions such as inflammatory response and innate immune defense against respiratory viral (i.e., human rhinovirus, HRV infection.We examined the effects of e-cigarette liquid (e-liquid on pro-inflammatory cytokine (e.g., IL-6 production, HRV infection and host defense molecules (e.g., short palate, lung, and nasal epithelium clone 1, SPLUNC1 in primary human airway epithelial cells from young healthy non-smokers. Additionally, we examined the role of SPLUNC1 in lung defense against HRV infection using a SPLUNC1 knockout mouse model. We found that nicotine-free e-liquid promoted IL-6 production and HRV infection. Addition of nicotine into e-liquid further amplified the effects of nicotine-free e-liquid. Moreover, SPLUNC1 deficiency in mice significantly increased lung HRV loads. E-liquid inhibited SPLUNC1 expression in primary human airway epithelial cells. These findings strongly suggest the deleterious health effects of e-cigarettes in the airways of young people. Our data will guide future studies to evaluate the impact of e-cigarettes on lung health in human populations, and help inform the public about potential health risks of e-cigarettes.

  8. Tracking Human-Induced Landscape Disturbance at the Nasca Lines UNESCO World Heritage Site in Peru with COSMO-SkyMed InSAR

    OpenAIRE

    Francesca Cigna; Deodato Tapete

    2018-01-01

    The “Lines and Geoglyphs of Nasca and Palpa” in Peru are among the most well-known UNESCO World Heritage Sites globally, and an exemplar of site where heritage assets cannot be separated from their natural and anthropogenic environment. The site is exposed to interactions with natural processes, as well as human presence. In this work, 3-m resolution synthetic aperture radar (SAR) StripMap HIMAGE HH-polarised scenes acquired by the X-band COSMO-SkyMed constellation are exploited to track two ...

  9. Advances in electronic-nose technologies for the detection of volatile biomarker metabolites in the human breath

    Science.gov (United States)

    Alphus D. Wilson

    2015-01-01

    Recent advancements in the use of electronic-nose (e-nose) devices to analyze human breath profiles for the presence of specific volatile metabolites, known as biomarkers or chemical bio-indicators of specific human diseases, metabolic disorders and the overall health status of individuals, are providing the potential for new noninvasive tools and techniques useful to...

  10. Features of infrasonic and ionospheric disturbances generated by launch vehicle

    International Nuclear Information System (INIS)

    Drobzheva, Ya.V.; Krasnov, V.M.; Sokolova, O.I.

    2001-01-01

    In this paper we present a model, which describe the propagation of acoustic pulses through a model terrestrial atmosphere produced by launch vehicle, and effects of these pulses on the ionosphere above the launch vehicle. We show that acoustic pulses generate disturbances of electron density. The value of these disturbances is about 0.04-0.7% of background electron density. So such disturbances can not create serious noise-free during monitoring of explosions by ionospheric method. We calculated parameters of the blast wave generated at the ionospheric heights by launch vehicle. It was shown that the blast wave is intense and it can generates disturbance of electron density which 2.6 times as much then background electron density. This disturbance is 'cord' with diameter about 150-250 m whereas length of radio line is hundreds and thousand km. Duration of ionospheric disturbances are from 0.2 s to 3-5 s. Such values of duration can not be observed during underground and surface explosions. (author)

  11. Effects of Thermal Resistance on One-Dimensional Thermal Analysis of the Epidermal Flexible Electronic Devices Integrated with Human Skin

    Science.gov (United States)

    Li, He; Cui, Yun

    2017-12-01

    Nowadays, flexible electronic devices are increasingly used in direct contact with human skin to monitor the real-time health of human body. Based on the Fourier heat conduction equation and Pennes bio-heat transfer equation, this paper deduces the analytical solutions of one - dimensional heat transfer for flexible electronic devices integrated with human skin under the condition of a constant power. The influence of contact thermal resistance between devices and skin is considered as well. The corresponding finite element model is established to verify the correctness of analytical solutions. The results show that the finite element analysis agrees well with the analytical solution. With bigger thermal resistance, temperature increase of skin surface will decrease. This result can provide guidance for the design of flexible electronic devices to reduce the negative impact that exceeding temperature leave on human skin.

  12. Sinusoidal obstruction syndrome (SOS): A light and electron microscopy study in human liver.

    Science.gov (United States)

    Vreuls, C P H; Driessen, A; Olde Damink, S W M; Koek, G H; Duimel, H; van den Broek, M A J; Dejong, C H C; Braet, F; Wisse, E

    2016-05-01

    Oxaliplatin is an important chemotherapeutic agent, used in the treatment of hepatic colorectal metastases, and known to induce the sinusoidal obstruction syndrome (SOS). Pathophysiological knowledge concerning SOS is based on a rat model. Therefore, the aim was to perform a comprehensive study of the features of human SOS, using both light microscopy (LM) and electron microscopy (EM). Included were all patients of whom wedge liver biopsies were collected during a partial hepatectomy for colorectal liver metastases, in a 4-year period. The wedge biopsy were perfusion fixated and processed for LM and EM. The SOS lesions were selected by LM and details were studied using EM. Material was available of 30 patients, of whom 28 patients received neo-adjuvant oxaliplatin. Eighteen (64%) of the 28 patients showed SOS lesions, based on microscopy. The lesions consisted of sinusoidal endothelial cell detachment from the space of Disse on EM. In the enlarged space of Disse a variable amount of erythrocytes were located. Sinusoidal endothelial cell detachment was present in human SOS, accompanied by enlargement of the space of Disse and erythrocytes in this area. These findings, originally described in a rat model, were now for the first time confirmed in human livers under clinically relevant settings. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Model reduction of nonlinear systems subject to input disturbances

    KAUST Repository

    Ndoye, Ibrahima

    2017-07-10

    The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order nonlinear system with similar disturbance-output properties to the original plant. The proposed model reduction strategy preserves the nonlinearity and the input disturbance nature of the model. It guarantees a sufficiently small error between the outputs of the original and the reduced-order systems, and also maintains the properties of input-to-state stability. The matrices of the reduced order system are given in terms of a set of linear matrix inequalities (LMIs). The paper concludes with a demonstration of the proposed approach on model reduction of a nonlinear electronic circuit with additive disturbances.

  14. The Size But not the Symmetry of the Wings of Eulaema nigrita Lepeletier (Apidae: Euglossini) is Affected by Human-Disturbed Landscapes in the Brazilian Cerrado Savanna.

    Science.gov (United States)

    Pinto, N S; Silva, D P; Rodrigues, J G; De Marco, P

    2015-10-01

    Among other human-related activities, habitat loss and fragmentation are currently ranked as the most important environmental features affecting the persistence of animal and plant populations in landscapes, as well as the maintenance of ecological processes and services. Since these processes are also capable of affecting the ontogenetic development of species inhabiting those landscapes, here we measured the wing veins of male Eulaema nigrita Lepeletier (Apidae: Euglossini) bees in order to evaluate whether the bees sampled in agriculture (AG) areas suffer higher fluctuating asymmetry (FA) than those sampled in Cerrado (CE) areas in the Brazilian state of Goiás. We believe that individuals sampled in CE areas would be less asymmetric than those sampled in AG areas, given a potential higher exposure of these specimens to environmental stresses (mostly pesticides). However, we did not observe a significant trend in the FA measures we obtained, although three wing measures were bigger for bees from CE areas. The lack of significant effects of FA may be related to inherent bionomic features of E. nigrita. For instance, given their high individual dispersal abilities, the individuals we analyzed may have developed in different areas than those where they were sampled. Their generalist feeding behavior may also have given them a higher resistance to environmental perturbations, buffering the normal development of immatures even in areas with local high environmental stress. Nonetheless, higher death rates of individuals from anthropic areas may also have killed the developing immatures of E. nigrita before they reached adulthood consequently equalizing our sampled estimates.

  15. Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

    International Nuclear Information System (INIS)

    Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.

    2012-01-01

    Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: ► Electron density of normal and neoplastic breast tissues was measured using Compton scattering. ► Monochromatic synchrotron radiation was used to obtain the Compton scattering data. ► The area of Compton peaks was used to determine the electron densities of samples. ► Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. ► Comparison with previous results showed differences smaller than 4%.

  16. Scaling disturbance instead of richness to better understand anthropogenic impacts on biodiversity.

    Directory of Open Access Journals (Sweden)

    Stephen J Mayor

    Full Text Available A primary impediment to understanding how species diversity and anthropogenic disturbance are related is that both diversity and disturbance can depend on the scales at which they are sampled. While the scale dependence of diversity estimation has received substantial attention, the scale dependence of disturbance estimation has been essentially overlooked. Here, we break from conventional examination of the diversity-disturbance relationship by holding the area over which species richness is estimated constant and instead manipulating the area over which human disturbance is measured. In the boreal forest ecoregion of Alberta, Canada, we test the dependence of species richness on disturbance scale, the scale-dependence of the intermediate disturbance hypothesis, and the consistency of these patterns in native versus exotic species and among human disturbance types. We related field observed species richness in 1 ha surveys of 372 boreal vascular plant communities to remotely sensed measures of human disturbance extent at two survey scales: local (1 ha and landscape (18 km2. Supporting the intermediate disturbance hypothesis, species richness-disturbance relationships were quadratic at both local and landscape scales of disturbance measurement. This suggests the shape of richness-disturbance relationships is independent of the scale at which disturbance is assessed, despite that local diversity is influenced by disturbance at different scales by different mechanisms, such as direct removal of individuals (local or indirect alteration of propagule supply (landscape. By contrast, predictions of species richness did depend on scale of disturbance measurement: with high local disturbance richness was double that under high landscape disturbance.

  17. Sleep Disturbances in Mood Disorders.

    Science.gov (United States)

    Rumble, Meredith E; White, Kaitlin Hanley; Benca, Ruth M

    2015-12-01

    The article provides an overview of common and differentiating self-reported and objective sleep disturbances seen in mood-disordered populations. The importance of considering sleep disturbances in the context of mood disorders is emphasized, because a large body of evidence supports the notion that sleep disturbances are a risk factor for onset, exacerbation, and relapse of mood disorders. In addition, potential mechanisms for sleep disturbance in depression, other primary sleep disorders that often occur with mood disorders, effects of antidepressant and mood-stabilizing drugs on sleep, and the adjunctive effect of treating sleep in patients with mood disorders are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Crystallite arrangement of hydroxyapatite microcrystals in human tooth cementum as revealed by electron paramagnetic resonance (EPR)

    International Nuclear Information System (INIS)

    Skaleric, U.; Gaspirc, B.; Cevc, P.; Schara, M.

    1998-01-01

    Human dental cementum was analyzed by electron paramagnetic resonance (EPR). The measured EPR powder spectra of γ-irradiated cementum resembled those of γirradiated enamel. Both spectra were characterized by the same line shapes and g values. The position of the extreme first derivate peaks can be described by g 1 =2.0023 and g 2 =1.9971±0.0002, and are assignable to the CO 3 3- center. The angular dependence of the cementum EPR spectra indicates a different arrangement of the hydroxyapatite microcrystals compared to that of enamel. A corresponding model of cementum micro-crystal alignment has been proposed. The methodology presented can be utilized for studying the mineralization process of root cementum and other mineralized tissues. (au)

  19. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces

    Science.gov (United States)

    Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon

    2018-01-01

    Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas. PMID:29364861

  20. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces

    Directory of Open Access Journals (Sweden)

    Robert Herbert

    2018-01-01

    Full Text Available Flexible hybrid electronics (FHE, designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.

  1. Electronic tracking of human resource skills and knowledge, just in time training, manageable due diligence

    Energy Technology Data Exchange (ETDEWEB)

    Kolodziej, M.A. [Quick Test International Inc., (Canada). Canadian Technology Human Resource Board; Baker, O. [KeySpan Energy Canada, Calgary, AB (Canada)

    2001-06-01

    KeySpan Energy Canada is in the process of obtaining recognition of various occupational profiles including pipeline operators, inspectors, and field and plant operators from various certifying organizations. The process of allowing individuals to obtain certification is recognized by Canadian Technology Human Resources Board as a step towards national standards for technologists and technicians. Proven competency is a must for workers in todays oil industry in response to increasingly stringent government safety regulations, environmental concerns and high public scrutiny. Quick Test international Inc. has developed a management tool in collaboration with end users at KeySpan Energy Canada. It is an electronic, Internet based competency tool for tracking personal competencies and maintaining continued competency. Response to the tool has been favourable. 2 refs., 4 figs.

  2. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces.

    Science.gov (United States)

    Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon; Yeo, Woon-Hong

    2018-01-24

    Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.

  3. Enzymatic-induced upconversion photoinduced electron transfer for sensing tyrosine in human serum.

    Science.gov (United States)

    Wu, Qiongqiong; Fang, Aijin; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2016-03-15

    This paper reports a novel nanosensor for tyrosine based on photoinduced electron-transfer (PET) between NaYF4:Yb, Tm upconversion nanoparticles (UCNPs) and melanin-like polymers. Melanin-like films were obtained from catalytic oxidation of tyrosine by tyrosinase, and deposited on the surface of UCNPs, and then quenched the fluorescence of UCNPs. Under the optimized conditions, the fluorescence quenching of UCNPs showed a good linear response to tyrosine concentration in the range of 0.8-100 μΜ with a detection limit of 1.1 μΜ. Meanwhile, it showed good sensitivity, stability and has been successfully applied to the detection of tyrosine in human serum. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Gene-specific characterization of human histone H2B by electron capture dissociation.

    Science.gov (United States)

    Siuti, Nertila; Roth, Michael J; Mizzen, Craig A; Kelleher, Neil L; Pesavento, James J

    2006-02-01

    The basis set of protein forms expressed by human cells from the H2B gene family was determined by Top Down Mass Spectrometry. Using Electron Capture Dissociation for MS/MS of H2B isoforms, direct evidence for the expression of unmodified H2B.Q, H2B.A, H2B.K/T, H2B.J, H2B.E, H2B.B, H2B.F, and monoacetylated H2B.A was obtained from asynchronous HeLa cells. H2B.A was the most abundant form, with the overall expression profile not changing significantly in cells arrested in mitosis by colchicine or during mid-S, mid-G2, G2/M, and mid-G1 phases of the cell cycle. Modest hyperacetylation of H2B family members was observed after sodium butyrate treatment.

  5. Protective effect of allium sativum ethanol extract on cultured human lymphocytes against electron beam radiation

    International Nuclear Information System (INIS)

    Rao, Shama; Shetty, Sukanya; Suchetha Kumari; Madhu, L.N.

    2013-01-01

    The development of radioprotective agent has been the subject of intense research because exposure to ionizing radiation causes DNA damage which may cause mutation and ultimately leads to cancer, on the other hand radiotherapy has become an integral part in treatment of cancer which uses ionizing radiations like X rays, gamma rays to kill the cancer cells. Amifostine is a well-known radioprotector which is clinically approved. There are many other radioprotectors like cysteine, cystamine, serotine but they are not used because of its normal tissue toxicity. Allium sativum is commonly known as garlic which has already been reported for its medicinal properties. In this study we evaluated radioprotection property of Allium sativum on DNA damage caused by electron beam radiation in cultured human lymphocytes. Allium sativum ethanol extract was used for this study. Cell viability was performed by MTT assay. DNA damage was assessed by comet assay parameters. The cultured lymphocytes were incubated with different concentrations 10, 50 and 100 μg/mL of Allium sativum extracts for 2, 4, 6 and 24 hour time intervals. Treatment of lymphocytes with various concentration of Allium sativum extract resulted in significant decrease in the level of DNA damage (Percentage tail DNA 6%) and increase in cell viability 93% (p>0.05) compare to the radiation control group. Results of this study revealed that Allium sativum protects cultured lymphocytes when exposed to electron beam radiation at its sub lethal dose. (author)

  6. The irradiation action on human dental tissue by X-rays and electrons. A nanoindenter study

    Energy Technology Data Exchange (ETDEWEB)

    Fraenzel, Wolfgang [Halle-Wittenberg Univ., Halle (Germany). Dept. of Physics; Gerlach, Reinhard [Halle-Wittenberg Univ., Halle (Germany). Clinic of Radiation Therapy

    2009-07-01

    It is known that ionizing radiation is used in medicine for Roentgen diagnostics and for radiation therapy. The radiation interacts with matter, in particular with biological one, essentially by scattering, photoelectric effect, Compton effect and pair production. To what extent the biological material is changed thereby, depends on the type and the amount of radiation energy, on the dose and on the tissue constitution. In modern radiation therapy two different kinds of radiation are used: high energy X-rays and electron radiation. In the case of head-neck tumors the general practice is an irradiation with high energy X-rays with absorbed dose to water up to 70 Gy. Teeth destruction has been identified as a side effect during irradiation. In addition, damage to the salivary glands is often observed which leads to a decrease or even the complete loss of the salivary secretion (xerostomia). This study shows how the different energy and radiation types damage the tooth tissue. The effects of both, high X-ray energy and high energy electrons, on the mechanical properties hardness and elasticity of the human dental tissue are measured by the nanoindentation technique. We compare these results with the effect of the irradiation of low X-ray energy on the dental tissue. (orig.)

  7. The irradiation action on human dental tissue by X-rays and electrons. A nanoindenter study

    International Nuclear Information System (INIS)

    Fraenzel, Wolfgang; Gerlach, Reinhard

    2009-01-01

    It is known that ionizing radiation is used in medicine for Roentgen diagnostics and for radiation therapy. The radiation interacts with matter, in particular with biological one, essentially by scattering, photoelectric effect, Compton effect and pair production. To what extent the biological material is changed thereby, depends on the type and the amount of radiation energy, on the dose and on the tissue constitution. In modern radiation therapy two different kinds of radiation are used: high energy X-rays and electron radiation. In the case of head-neck tumors the general practice is an irradiation with high energy X-rays with absorbed dose to water up to 70 Gy. Teeth destruction has been identified as a side effect during irradiation. In addition, damage to the salivary glands is often observed which leads to a decrease or even the complete loss of the salivary secretion (xerostomia). This study shows how the different energy and radiation types damage the tooth tissue. The effects of both, high X-ray energy and high energy electrons, on the mechanical properties hardness and elasticity of the human dental tissue are measured by the nanoindentation technique. We compare these results with the effect of the irradiation of low X-ray energy on the dental tissue. (orig.)

  8. Electronic cigarettes and indoor air quality: a review of studies using human volunteers.

    Science.gov (United States)

    Zainol Abidin, Najihah; Zainal Abidin, Emilia; Zulkifli, Aziemah; Karuppiah, Karmegam; Syed Ismail, Sharifah Norkhadijah; Amer Nordin, Amer Siddiq

    2017-09-26

    This paper is primarily aimed to review articles on electronic cigarettes (e-cigarettes) focusing on indoor air quality (IAQ) assessment that were conducted using human volunteers under natural settings that mimic actual vaping scenarios. Such studies may give a better representation of the actual potential exposure towards e-cigarettes emissions in indoor settings. A systematic literature search was conducted using PubMed search engine database. Search terms such as "electronic cigarette", "e-cigarette", "electronic nicotine delivery system", and "indoor air quality" were used to identify the relevant articles to be included in this review. Articles that involved human volunteers who were asked to vape in natural settings or settings that mimic the actual vaping scenario were chosen to be reviewed. The search yielded a total of 15 published articles. Eleven articles were excluded due to 1) unavailability of its full-text (n=1), 2) did not involve human volunteers (n=5) and 3) did not involve an IAQ study (n=5). Four articles were critically reviewed in this paper. From the four selected articles, two of the papers focused on the determination of nicotine level released by e-cigarettes whereas the other two covered IAQ parameters namely; particulate matters (PM), propylene glycols, formaldehyde, metals and polycyclic aromatic hydrocarbons (PAHs). Only two of the studies involved determination of biomarkers of exposure. The level of chemical contents released varied between studies. The differences in the brands of e-cigarette used, number of vapers recruited and the sensitivity of the methodologies employed in these studies may be the possible causes for such differences. However, studies using human volunteers conducted in a natural setting are more relevant to portray the actual exposure to vapors among e-cigarettes users and non-users compared to studies using a smoking machine/an exposure chamber. This is because such studies take into account the behavior of

  9. Ionospheric disturbance dynamo

    International Nuclear Information System (INIS)

    Blanc, M.; Richmond, A.D.

    1980-01-01

    A numerical simulation study of the thermospheric winds produced by auroral heating during magnetic storms, and of their global dynamo effects, establishes the main features of the ionospheric disturbanc dynamo. Driven by auroral heating, a Hadley cell is created with equatorward winds blowing above about 120 km at mid-latitudes. The transport of angular momentum by these winds produces a subrotation of the midlatitude thermosphere, or westward motion with respect to the earth. The westward winds in turn drive equatorward Pedersen currents which accumulate charge toward the equator, resulting in the generation of a poleward electric field, a westward E x B drift, and an eastward current. When realistic local time conductivity variations are simulated, the eastward mid-latitude current is found to close partly via lower latitudes, resulting in an 'anti-Sq' type of current vortex. Both electric field and current at low latitudes thus vary in opposition to their normal quiet-day behavior. This total pattern of distrubance winds, electric fields, and currents is superimposed upon the background quiet-day pattern. When the neutral winds are artificially confined on the nightside, the basic pattern of predominantly westward E x B plasma drifts still prevails on the nightside but no longer extends into the dayside. Considerable observational evidence exists, suggesting that the ionospheric disturbance dynamo has an appreciable influence on storm-time ionospheric electric fields at middle and low latitudes

  10. RHYTHM DISTURBANCES DURING COLONOSCOPY

    Directory of Open Access Journals (Sweden)

    D. Jordanov

    2012-08-01

    Full Text Available Purpose: The purpose of this study is to assess the risk of inducing rhythm disturbances of the heart during colonoscopy.Patients and methods used: 80 patients had undergone colonoscopyper formed by two experienced specialists of endoscopy for the period from March to December 2011. The endoscopies were performed without premedication and sedation. Holter was placed on each patient one hour before the endoscopic examination, and the record continued one hour after the manipulation. The blood pressure was measured before, during and after the procedure.Results: During colonoscopy 25 patients (31,25% manifested rhythm disorders. In 15 patients (18,75% sinus tachycardia occurred. In 7 patients (8,75% suptraventricular extra systoles were observed and in 3 patients (3,75% - ventricular extra systoles. No ST-T changes were found. Highest values of the blood pressure were measured before and during the endoscopy, but the values did not exceed 160/105 mmHg. In 10 patients (12,5% a hypotensive reaction was observed, bur the values were not lower than 80/ 50. In 2 patients there was a short bradycardia with a heart frequency 50-55 /min.Conclusions: Our results showed that the rhythm disorders during lower colonoscopy occur in approximately 1/3 of the examined patients, there is an increase or decrease of the blood pressure in some patients, but that doesn’t require physician’s aid and the examination can be carried out safely without monitoring.

  11. Electronic speckle-pattern interferometry (ESPI) applied to the study of mechanical behavior of human jaws

    Science.gov (United States)

    Roman, Juan F.; Moreno de las Cuevas, Vincente; Salgueiro, Jose R.; Suarez, David; Fernandez, Paula; Gallas, Mercedes; Blanchard, Alain

    1996-01-01

    The study of the mechanical behavior of the human jaw during chewing is helpful in several specific medical fields that cover the maxillo-facial area. In this work, electronic speckle pattern interferometry has been applied to study dead jaw bones under external stress which simulates the deformations induced during chewing. Fringes obtained after subtraction of two images of the jaw, the image of the relaxed jaw and that of the jaw under stress, give us information about the most stressed zones. The interferometric analysis proposed here is attractive as it can be done in real time with the jaw under progressive stress. Image processing can be applied for improving the quality of fringes. This research can be of help in orthognathic surgery, for example in diagnosis and treatment of fractured jaws, in oral surgery, and in orthodontics because it would help us to know the stress dispersion when we insert an osseointegrated implant or place an orthodontic appliance, respectively. Studying fragments of human jaw some results about its elasticity and flexibility were obtained.

  12. Detection and Classification of Human Body Odor Using an Electronic Nose

    Directory of Open Access Journals (Sweden)

    Teerakiat Kerdcharoen

    2009-09-01

    Full Text Available An electronic nose (E-nose has been designed and equipped with software that can detect and classify human armpit body odor. An array of metal oxide sensors was used for detecting volatile organic compounds. The measurement circuit employs a voltage divider resistor to measure the sensitivity of each sensor. This E-nose was controlled by in-house developed software through a portable USB data acquisition card with a principle component analysis (PCA algorithm implemented for pattern recognition and classification. Because gas sensor sensitivity in the detection of armpit odor samples is affected by humidity, we propose a new method and algorithms combining hardware/software for the correction of the humidity noise. After the humidity correction, the E-nose showed the capability of detecting human body odor and distinguishing the body odors from two persons in a relative manner. The E-nose is still able to recognize people, even after application of deodorant. In conclusion, this is the first report of the application of an E-nose for armpit odor recognition.

  13. Detection and classification of human body odor using an electronic nose.

    Science.gov (United States)

    Wongchoosuk, Chatchawal; Lutz, Mario; Kerdcharoen, Teerakiat

    2009-01-01

    An electronic nose (E-nose) has been designed and equipped with software that can detect and classify human armpit body odor. An array of metal oxide sensors was used for detecting volatile organic compounds. The measurement circuit employs a voltage divider resistor to measure the sensitivity of each sensor. This E-nose was controlled by in-house developed software through a portable USB data acquisition card with a principle component analysis (PCA) algorithm implemented for pattern recognition and classification. Because gas sensor sensitivity in the detection of armpit odor samples is affected by humidity, we propose a new method and algorithms combining hardware/software for the correction of the humidity noise. After the humidity correction, the E-nose showed the capability of detecting human body odor and distinguishing the body odors from two persons in a relative manner. The E-nose is still able to recognize people, even after application of deodorant. In conclusion, this is the first report of the application of an E-nose for armpit odor recognition.

  14. Assessment of a Standardized ROS Production Profile in Humans by Electron Paramagnetic Resonance

    Directory of Open Access Journals (Sweden)

    Simona Mrakic-Sposta

    2012-01-01

    Full Text Available Despite the growing interest in the role of reactive oxygen species (ROS in health and disease, reliable quantitative noninvasive methods for the assessment of oxidative stress in humans are still lacking. EPR technique, coupled to a specific spin probe (CMH: 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine is here presented as the method of choice to gain a direct measurement of ROS in biological fluids and tissues. The study aimed at demonstrating that, differently from currently available “a posteriori” assays of ROS-induced damage by means of biomolecules (e.g., proteins and lipids spin-trapping EPR provides direct evidence of the “instantaneous” presence of radical species in the sample and, as signal areas are proportional to the number of excited electron spins, lead to absolute concentration levels. Using a recently developed bench top continuous wave system (e-scan EPR scanner, Bruker dealing with very low ROS concentration levels in small (50 μL samples, we successfully monitored rapid ROS production changes in peripheral blood of athletes after controlled exercise and sedentary subjects after antioxidant supplementation. The correlation between EPR results and data obtained by various enzymatic assays (e.g., protein carbonyls and thiobarbituric acid reactive substances was determined too. Synthetically, our method allows reliable, quick, noninvasive quantitative determination of ROS in human peripheral blood.

  15. DNA-mediated strand displacement facilitates sensitive electronic detection of antibodies in human serums.

    Science.gov (United States)

    Dou, Baoting; Yang, Jianmei; Shi, Kai; Yuan, Ruo; Xiang, Yun

    2016-09-15

    We describe here the development of a sensitive and convenient electronic sensor for the detection of antibodies in human serums. The sensor is constructed by self-assembly formation of a mixed monolayer containing the small molecule epitope conjugated double stranded DNA probes on gold electrode. The target antibody binds the epitope on the dsDNA probe and lowers the melting temperature of the duplex, which facilitates the displacement of the antibody-linked strand of the duplex probe by an invading methylene blue-tagged single stranded DNA (MB-ssDNA) through the strand displacement reaction and leads to the capture of many MB-ssDNA on the sensor surface. Subsequent electrochemical oxidation of the methylene blue labels results in amplified current response for sensitive monitoring of the antibodies. The antibody assay conditions are optimized and the sensor exhibits a linear range between 1.0 and 25.0nM with a detection limit of 0.67nM for the target antibody. The sensor is also selective and can be employed to detect the target antibodies in human serum samples. With the advantages of using small molecule epitope as the antibody recognition element over traditional antigen, the versatile manipulability of the DNA probes and the unique properties of the electrochemical transduction technique, the developed sensor thus hold great potential for simple and sensitive detection of different antibodies and other proteins in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Sleep disturbances and glucose homeostasis

    NARCIS (Netherlands)

    Barf, R. Paulien; Scheurink, Anton J.W.

    2011-01-01

    Sleep disturbances, induced by either lifestyle, shift work or sleeping disorders, have become more prevalent in our 24/7 Western society. Sleep disturbances are associated with impaired health including metabolic diseases such as obesity and type 2 diabetes. The question remains whether there is a

  17. Potential Environmental and Human Health Impacts of Rechargeable Lithium Batteries in Electronic Waste

    Science.gov (United States)

    Kang, Daniel Hsing Po; Chen, Mengjun; Ogunseitan, Oladele A.

    2013-01-01

    Rechargeable lithium-ion (Li-ion) and lithium-polymer (Li-poly) batteries have recently become dominant in consumer electronic products because of advantages associated with energy density and product longevity. However, the small size of these batteries, the high rate of disposal of consumer products in which they are used, and the lack of uniform regulatory policy on their disposal means that lithium batteries may contribute substantially to environmental pollution and adverse human health impacts due to potentially toxic materials. In this research, we used standardized leaching tests, life-cycle impact assessment (LCIA), and hazard assessment models to evaluate hazardous waste classification, resource depletion potential, and toxicity potentials of lithium batteries used in cellphones. Our results demonstrate that according to U.S. federal regulations, defunct Li-ion batteries are classified hazardous due to their lead (Pb) content (average 6.29 mg/L; σ = 11.1; limit 5). However, according to California regulations, all lithium batteries tested are classified hazardous due to excessive levels of cobalt (average 163 544 mg/kg; σ = 62 897; limit 8000), copper (average 98 694 mg/kg; σ = 28 734; limit 2500), and nickel (average 9525 mg/kg; σ = 11 438; limit 2000). In some of the Li-ion batteries, the leached concentrations of chromium, lead, and thallium exceeded the California regulation limits. The environmental impact associated with resource depletion and human toxicity is mainly associated with cobalt, copper, nickel, thallium, and silver, whereas the ecotoxicity potential is primarily associated with cobalt, copper, nickel, thallium, and silver. However, the relative contribution of aluminum and lithium to human toxicity and ecotoxicity could not be estimated due to insufficient toxicity data in the models. These findings support the need for stronger government policy at the local, national, and international levels to encourage recovery, recycling, and

  18. Advances in Electronic-Nose Technologies for the Detection of Volatile Biomarker Metabolites in the Human Breath

    Directory of Open Access Journals (Sweden)

    Alphus D. Wilson

    2015-03-01

    Full Text Available Recent advancements in the use of electronic-nose (e-nose devices to analyze human breath profiles for the presence of specific volatile metabolites, known as biomarkers or chemical bio-indicators of specific human diseases, metabolic disorders and the overall health status of individuals, are providing the potential for new noninvasive tools and techniques useful to point-of-care clinical disease diagnoses. This exciting new area of electronic disease detection and diagnosis promises to yield much faster and earlier detection of human diseases and disorders, allowing earlier, more effective treatments, resulting in more rapid patient recovery from various afflictions. E-nose devices are particularly suited for the field of disease diagnostics, because they are sensitive to a wide range of volatile organic compounds (VOCs and can effectively distinguish between different complex gaseous mixtures via analysis of electronic aroma sensor-array output profiles of volatile metabolites present in the human breath. This review provides a summary of some recent developments of electronic-nose technologies, particularly involving breath analysis, with the potential for providing many new diagnostic applications for the detection of specific human diseases associated with different organs in the body, detectable from e-nose analyses of aberrant disease-associated VOCs present in air expired from the lungs.

  19. Myostatin and carbohydrate disturbances.

    Science.gov (United States)

    Assyov, Yavor S; Velikova, Tsvetelina V; Kamenov, Zdravko A

    2017-05-01

    Purpose/aim of the study: Myostatin is a myokine that has been shown to inhibit muscle growth and to have potentially deleterious effects on metabolism. The aim of the current study was to compare its circulating serum levels in subjects from the whole spectrum of carbohydrate disturbances leading to diabetes. A total of 159 age-, sex-, and BMI-matched subjects participated in the study - 50 had normal glucose tolerance (NGT), 60 had prediabetes (PreDM), and 49 had type 2 diabetes mellitus (T2D). Oral glucose tolerance testing was used to determine glucose tolerance. Serum myostatin was quantified by means of ELISA. Circulating serum myostatin levels were highest in patients with T2D, lower in subjects with prediabetes, and lowest in subjects with normoglycemia (all p Myostatin was shown to be positively associated with fasting plasma glucose, HOMA-IR, hepatic enzymes, uric acid, and FINDRISC questionnaire scores in both sexes. ROC analyses determined circulating myostatin levels to be of value for differentiating subjects with T2D (AUC = 0.72, p = 0.002 in men; AUC = 0.70, p = 0.004 in women) in the study population. After adjustment for potential confounders, in a multiple binary logistic regression model, serum myostatin added further information to traditional risk estimates in distinguishing subjects with T2D. Serum myostatin levels are higher with deterioration of carbohydrate tolerance. Furthermore, circulating myostatin is positively associated with traditional biochemical estimates of poor metabolic health. These data add to evidence of the involvement of this myokine in the pathogenesis of T2D.

  20. Natural disturbance impacts on Canada's forest carbon budget

    International Nuclear Information System (INIS)

    Kurz, W.

    2004-01-01

    Wildfire and insect outbreaks are major determinants of forest dynamics in Canada, transferring carbon within the ecosystem, releasing carbon into the atmosphere and influencing post-disturbance carbon dynamics. This paper discusses the impacts of global climate change on natural disturbances. Higher temperatures and drier conditions are likely to increase burned areas in Canada and will also increase the impacts of insects, allowing for an expanded range and stressing their host species. Long-term changes in disturbance regimes have already affected Canada's forest age-class structure. Statistics of lower disturbance periods and carbon production were compared with periods of higher disturbance. Scenario analyses were conducted for the period of 1996 to 2032, assuming that annual insect and fire disturbance rates in timber-productive forests were 20 per cent higher and carbon production 20 per cent lower than base scenarios using average disturbance rates. It was concluded that these conditions could cause carbon stocks in Canada's forests to decline. The future carbon balance of Canada's forests will be affected by the rate of natural and human-induced disturbances. 4 refs

  1. Electronic Human Resources Management (e-HRM Adoption Studies: Past and Future Research

    Directory of Open Access Journals (Sweden)

    Winarto Winarto

    2018-05-01

    Full Text Available Electronic human resource management (e-HRM systems become more widely used by profit and non-profit organization. However, the field currently lacks sound theoretical frameworks that can be useful in addressing a key issue concerning the implementation of e-HRM systems, in particular to obtain a better understanding of the factors influencing the adoption of e-HRM systems. The objective of this paper is to provide a foundation towards the development of a theoretical framework for the implementation of e-HRM systems and develop a conceptual model that would reflect the nature of e-HRM systems’ adoption through systematic literature review. Adopting Crossan and Apaydin’s procedure of systematic review, this paper investigated 21 empirical papers of electronics human resources management, then categorized them into 4 characteristics which influence the adoption; System and technology characteristics; Organizational characteristics; User/individual characteristics, and Environmental and contextual characteristics. Finally, the e-HRM adoption research framework is drawn and based on the framework; avenues for future research are discussed.   Bahasa Indonesia Abstrak: Manajemen sumber daya manusia elektronik (selanjutnya disebut dengan e-HRM semakin banyak digunakan oleh organisasi profit dan nonprofit. Namun, bidang dan topik ini belum memiliki kerangka teori yang mapan, yang dapat digunakan untuk menganalisis isu-isu terkait penerapan e-HRM, terutama mengenai faktor-faktor yang mempengaruhi adopsi sistem e-HRM. Tujuan penelitian ini adalah untuk memberikan landasan bagi pengembangan kerangka teoritis untuk implementasi sistem e-HRM dan mengembangkan model konseptual yang akan menggambarkan adopsi sistem e-HRM melalui tinjauan literatur sistematis. Mengadopsi prosedur dan metode Crossan dan Apaydin untuk melakukan telaah literatur secara sistematis, paper ini menyelidiki 21 publikasi empiris manajemen sumber daya manusia elektronik dari 2

  2. Electronic structure of human hemoglobin: ultrasoft X-ray emission study

    International Nuclear Information System (INIS)

    Soldatov, A.V.; Kravtsova, A.N.; Fedorovich, E.N.; Kurmaev, E.Z.; Moewes, A.

    2004-01-01

    Full text: The iron L 2,3 and carbon, nitrogen and oxygen Kα X-ray emission spectra (XES) of human hemoglobin have been recorded at the soft X-ray spectroscopy endstation on Undulator Beam line 8.0 at Advanced Light Source (ALS) located at the Lawrence Berkeley National Laboratory. The theoretical calculations of Fe L 3 -XES have been performed using ab initio code FEFF8.2. The calculations have been carried out for the structure of hemoglobin presented in PDB (entry 3HHB) as well as for the molecule with symmetrical heme plane. It was found that the Fe L 3 emission spectrum calculated for the ideal molecule agrees slightly better with the experiment as compared with those calculated for the real molecule. Thus, one can use the structure of the ideal molecule for theoretical Fe L 3 -XES simulations. The theoretical analysis has shown that the fist peak of experimental Fe L 3 - emission spectrum is enhanced by the nearest nitrogen atoms lying in heme plane around the central iron atom. The theoretical C K- and N K-XES spectra of hemoglobin have been calculated. A good agreement between theoretical and experimental spectra has been obtained. The distribution of the partial electronic densities of states in the valence and conduction bands of hemoglobin has been determined

  3. Warfarin traps human vitamin K epoxide reductase in an intermediate state during electron transfer

    Science.gov (United States)

    Shen, Guomin; Cui, Weidong; Zhang, Hao; Zhou, Fengbo; Huang, Wei; Liu, Qian; Yang, Yihu; Li, Shuang; Bowman, Gregory R.; Sadler, J. Evan; Gross, Michael L.; Li, Weikai

    2017-01-01

    Although warfarin is the most widely used anticoagulant worldwide, the mechanism by which warfarin inhibits its target, human vitamin K epoxide reductase (hVKOR), remains unclear. Here we show that warfarin blocks a dynamic electron-transfer process in hVKOR. A major fraction of cellular hVKOR is at an intermediate redox state of this process containing a Cys51-Cys132 disulfide, a characteristic accommodated by a four-transmembrane-helix structure of hVKOR. Warfarin selectively inhibits this major cellular form of hVKOR, whereas disruption of the Cys51-Cys132 disulfide impairs warfarin binding and causes warfarin resistance. Relying on binding interactions identified by cysteine alkylation footprinting and mass spectrometry coupled with mutagenesis analysis, we are able to conduct structure simulations to reveal a closed warfarin-binding pocket stabilized by the Cys51-Cys132 linkage. Understanding the selective warfarin inhibition of a specific redox state of hVKOR should enable the rational design of drugs that exploit the redox chemistry and associated conformational changes in hVKOR. PMID:27918545

  4. Encapsulated sensory corpuscle in the mucosa of human vocal cord: an electron microscope study.

    Science.gov (United States)

    Nagai, T

    1982-05-01

    Encapsulated sensory corpuscles of the Krause type were found in the mucosa of surgically removed human vocal cords. The corpuscles were ellipsoidal structures of about 30 to 50 micrometers and were located beneath the free edge in the mid-region along the intermembranous part. They contained a number of varicose nerve endings and lamellar cells. The lamellar cells had thin cytoplasmic lamellae which contained numerous cytoplasmic filaments and were interposed between the nerve endings. Attachment devices were frequently noted between the cytoplasmic lamellae and between the lamellae and nerve endings. Half-desmosomes were also noted along the plasma membrane of the lamellar cells. The intercellular space was filled with amorphous electron lucent material and contained a few collagen fibrils. Ladder-like filamentous structures were frequently encountered in the intercellular space. The location of the corpuscles at the free edge of the vocal cords suggests that the endings may receive the bilateral touch of the vibrating part of the cords in order to give sensory information for the control of the movement of the cords in phonation.

  5. Electron spin relaxation enhancement measurements of interspin distances in human, porcine, and Rhodobacter electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO).

    Science.gov (United States)

    Fielding, Alistair J; Usselman, Robert J; Watmough, Nicholas; Simkovic, Martin; Frerman, Frank E; Eaton, Gareth R; Eaton, Sandra S

    2008-02-01

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a membrane-bound electron transfer protein that links primary flavoprotein dehydrogenases with the main respiratory chain. Human, porcine, and Rhodobacter sphaeroides ETF-QO each contain a single [4Fe-4S](2+,1+) cluster and one equivalent of FAD, which are diamagnetic in the isolated enzyme and become paramagnetic on reduction with the enzymatic electron donor or with dithionite. The anionic flavin semiquinone can be reduced further to diamagnetic hydroquinone. The redox potentials for the three redox couples are so similar that it is not possible to poise the proteins in a state where both the [4Fe-4S](+) cluster and the flavoquinone are fully in the paramagnetic form. Inversion recovery was used to measure the electron spin-lattice relaxation rates for the [4Fe-4S](+) between 8 and 18K and for semiquinone between 25 and 65K. At higher temperatures the spin-lattice relaxation rates for the [4Fe-4S](+) were calculated from the temperature-dependent contributions to the continuous wave linewidths. Although mixtures of the redox states are present, it was possible to analyze the enhancement of the electron spin relaxation of the FAD semiquinone signal due to dipolar interaction with the more rapidly relaxing [4Fe-4S](+) and obtain point-dipole interspin distances of 18.6+/-1A for the three proteins. The point-dipole distances are within experimental uncertainty of the value calculated based on the crystal structure of porcine ETF-QO when spin delocalization is taken into account. The results demonstrate that electron spin relaxation enhancement can be used to measure distances in redox poised proteins even when several redox states are present.

  6. Microbial Remobilisation on Riverbed Sediment Disturbance in Experimental Flumes and a Human-Impacted River: Implication for Water Resource Management and Public Health in Developing Sub-Saharan African Countries

    Directory of Open Access Journals (Sweden)

    Akebe Luther King Abia

    2017-03-01

    Full Text Available Resuspension of sediment-borne microorganisms (including pathogens into the water column could increase the health risk for those using river water for different purposes. In the present work, we (1 investigated the effect of sediment disturbance on microbial resuspension from riverbed sediments in laboratory flow-chambers and in the Apies River, Gauteng, South Africa; and (2 estimated flow conditions for sediment-borne microorganism entrainment/resuspension in the river. For mechanical disturbance, the top 2 cm of the sediment in flow-chambers was manually stirred. Simulating sudden discharge into the river, water (3 L was poured within 30 s into the chambers at a 45° angle to the chamber width. In the field, sediment was disturbed by raking the riverbed and by cows crossing in the river. Water samples before and after sediment disturbance were analysed for Escherichia coli. Sediment disturbance caused an increase in water E. coli counts by up to 7.9–35.8 times original values. Using Shields criterion, river-flow of 0.15–0.69 m3/s could cause bed particle entrainment; while ~1.57–7.23 m3/s would cause resuspension. Thus, sediment disturbance in the Apies River would resuspend E. coli (and pathogens, with possible negative health implications for communities using such water. Therefore, monitoring surface water bodies should include microbial sediment quality.

  7. Microbial Remobilisation on Riverbed Sediment Disturbance in Experimental Flumes and a Human-Impacted River: Implication for Water Resource Management and Public Health in Developing Sub-Saharan African Countries

    Science.gov (United States)

    Abia, Akebe Luther King; James, Chris; Ubomba-Jaswa, Eunice; Benteke Momba, Maggy Ndombo

    2017-01-01

    Resuspension of sediment-borne microorganisms (including pathogens) into the water column could increase the health risk for those using river water for different purposes. In the present work, we (1) investigated the effect of sediment disturbance on microbial resuspension from riverbed sediments in laboratory flow-chambers and in the Apies River, Gauteng, South Africa; and (2) estimated flow conditions for sediment-borne microorganism entrainment/resuspension in the river. For mechanical disturbance, the top 2 cm of the sediment in flow-chambers was manually stirred. Simulating sudden discharge into the river, water (3 L) was poured within 30 s into the chambers at a 45° angle to the chamber width. In the field, sediment was disturbed by raking the riverbed and by cows crossing in the river. Water samples before and after sediment disturbance were analysed for Escherichia coli. Sediment disturbance caused an increase in water E. coli counts by up to 7.9–35.8 times original values. Using Shields criterion, river-flow of 0.15–0.69 m3/s could cause bed particle entrainment; while ~1.57–7.23 m3/s would cause resuspension. Thus, sediment disturbance in the Apies River would resuspend E. coli (and pathogens), with possible negative health implications for communities using such water. Therefore, monitoring surface water bodies should include microbial sediment quality. PMID:28295001

  8. Microbial Remobilisation on Riverbed Sediment Disturbance in Experimental Flumes and a Human-Impacted River: Implication for Water Resource Management and Public Health in Developing Sub-Saharan African Countries.

    Science.gov (United States)

    Abia, Akebe Luther King; James, Chris; Ubomba-Jaswa, Eunice; Benteke Momba, Maggy Ndombo

    2017-03-15

    Resuspension of sediment-borne microorganisms (including pathogens) into the water column could increase the health risk for those using river water for different purposes. In the present work, we (1) investigated the effect of sediment disturbance on microbial resuspension from riverbed sediments in laboratory flow-chambers and in the Apies River, Gauteng, South Africa; and (2) estimated flow conditions for sediment-borne microorganism entrainment/resuspension in the river. For mechanical disturbance, the top 2 cm of the sediment in flow-chambers was manually stirred. Simulating sudden discharge into the river, water (3 L) was poured within 30 s into the chambers at a 45° angle to the chamber width. In the field, sediment was disturbed by raking the riverbed and by cows crossing in the river. Water samples before and after sediment disturbance were analysed for Escherichia coli. Sediment disturbance caused an increase in water E. coli counts by up to 7.9-35.8 times original values. Using Shields criterion, river-flow of 0.15-0.69 m³/s could cause bed particle entrainment; while ~1.57-7.23 m³/s would cause resuspension. Thus, sediment disturbance in the Apies River would resuspend E. coli (and pathogens), with possible negative health implications for communities using such water. Therefore, monitoring surface water bodies should include microbial sediment quality.

  9. Age structure and disturbance legacy of North American forests

    Directory of Open Access Journals (Sweden)

    Y. Pan

    2011-03-01

    Full Text Available Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is a useful surrogate variable for analyses of the impact of disturbance on forest carbon. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS project. A companion map of the standard deviations for age estimates was developed for quantifying uncertainty. We discuss the significance of the disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, by analyzing the causes of disturbances from land management and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing this rate as a result of direct human intervention in the disturbance/age status. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.

  10. Disturbance, diversity and distributions in Central African rain forest

    NARCIS (Netherlands)

    Gemerden, van B.S.

    2004-01-01

    The aim of this study is to gain insight in the impact of human land use on plant community composition, diversity and levels of endemism in Central African rain forest. Human disturbance in this region is causing large-scale habitat degradation. The two most widespread forms of land use are

  11. Dose rate effect on micronuclei induction in human blood lymphocytes exposed to single pulse and multiple pulses of electrons.

    Science.gov (United States)

    Acharya, Santhosh; Bhat, N N; Joseph, Praveen; Sanjeev, Ganesh; Sreedevi, B; Narayana, Y

    2011-05-01

    The effects of single pulses and multiple pulses of 7 MV electrons on micronuclei (MN) induction in cytokinesis-blocked human peripheral blood lymphocytes (PBLs) were investigated over a wide range of dose rates per pulse (instantaneous dose rate). PBLs were exposed to graded doses of 2, 3, 4, 6, and 8 Gy of single electron pulses of varying pulse widths at different dose rates per pulse, ranging from 1 × 10(6) Gy s(-1) to 3.2 × 10(8) Gy s(-1). Different dose rates per pulse were achieved by changing the dose per electron pulse by adjusting the beam current and pulse width. MN yields per unit absorbed dose after irradiation with single electron pulses were compared with those of multiple pulses of electrons. A significant decrease in the MN yield with increasing dose rates per pulse was observed, when dose was delivered by a single electron pulse. However, no reduction in the MN yield was observed when dose was delivered by multiple pulses of electrons. The decrease in the yield at high dose rates per pulse suggests possible radical recombination, which leads to decreased biological damage. Cellular response to the presence of very large numbers of chromosomal breaks may also alter the damage.

  12. Exploring ultrashort high-energy electron-induced damage in human carcinoma cells

    International Nuclear Information System (INIS)

    Rigaud, O.; Fortunel, N.O.; Vaigot, P.; Cadio, E.; Martin, M.T.; Lundh, O.; Faure, J.; Rechatin, C.; Malka, V.; Gauduel, Y.A.

    2010-01-01

    In conventional cancer therapy or fundamental radiobiology research, the accumulated knowledge on the complex responses of healthy or diseased cells to ionizing radiation is generally obtained with low-dose rates. Under these radiation conditions, the time spent for energy deposition is very long compared with the dynamics of early molecular and cellular responses. The use of ultrashort pulsed radiation would offer new perspectives for exploring the 'black box' aspects of long irradiation profiles and favouring the selective control of early damage in living targets. Several attempts were previously performed using nanosecond or picosecond pulsed irradiations on various mammalian cells and radiosensitive mutants at high dose rate. The effects of single or multi-pulsed radiations on cell populations were generally analyzed in the framework of dose survival curves or characterized by 2D imaging of γ-H2AX foci and no increase in cytotoxicity was shown compared with a delivery at a conventional dose rate. Moreover, when multi-shot irradiations were performed, the overall time needed to obtain an integrated dose of several Grays again overlapped with the multi-scale dynamics of bio-molecular damage-repair sequences and cell signalling steps. Ideally, a single-shot irradiation delivering a well-defined energy profile, via a very short temporal window, would permit the approach of a real-time investigation of early radiation induced molecular damage within the confined spaces of cell compartments. Owing to the potential applications of intense ultrashort laser for radiation therapy, the model of the A431 carcinoma cell line was chosen. An ultrafast single-shot irradiation strategy was carried out with these radio-resistant human skin carcinoma cells, using the capacity of an innovating laser-plasma accelerator to generate quasi mono-energetic femtosecond electron bunches in the MeV domain and to deliver a very high dose rate of 10 13 Gy s -1 per pulse. The alkaline comet

  13. Biofuels - 5 disturbing questions

    International Nuclear Information System (INIS)

    Legalland, J.P.; Lemarchand, J.L.

    2008-01-01

    Initially considered as the supreme weapon against greenhouse gas emissions, biofuels are today hold responsible to all harms of the Earth: leap of agriculture products price, deforestation, food crisis. Considered some time ago as the perfect clean substitute to petroleum, biofuels are now suspected to have harmful effects on the environment. Should it be just an enormous technical, environmental and human swindle? Should we abandon immediately biofuels to protect the earth and fight the threatening again starvation? Should we wait for the second generation of efficient biofuels, made from non food-derived products and cultivation wastes? This book analyses this delicate debate through 5 main questions: do they starve the world? Are they a clean energy source? Do they contribute to deforestation? Are they economically practicable? Is the second generation ready? (J.S.)

  14. Disturbed by "the stranger"

    DEFF Research Database (Denmark)

    Øland, Trine; Moldenhawer, Bolette

    2013-01-01

    This article addresses two questions. First: How does a state, in casu the Danish welfare state, based on universalism and social rights as regards its citizens, deal with immigrants and their descendants through education? Second: How does such a state manage to make its differential treatment...... of human beings work legitimately, i.e., what arguments, what interventions and moralisations, are used through the workings of school education? The article carries out an analysis of policies since the 1980s and depicts the construction of ‘the stranger’ parallel to an analysis of the state crafting...... processes that goes on in terms of professional educational interventions in Højmarken School, a school placed in an urban poor area....

  15. Observation and simulation of the ionosphere disturbance waves triggered by rocket exhausts

    Science.gov (United States)

    Lin, Charles C. H.; Chen, Chia-Hung; Matsumura, Mitsuru; Lin, Jia-Ting; Kakinami, Yoshihiro

    2017-08-01

    Observations and theoretical modeling of the ionospheric disturbance waves generated by rocket launches are investigated. During the rocket passage, time rate change of total electron content (rTEC) enhancement with the V-shape shock wave signature is commonly observed, followed by acoustic wave disturbances and region of negative rTEC centered along the trajectory. Ten to fifteen min after the rocket passage, delayed disturbance waves appeared and propagated along direction normal to the V-shape wavefronts. These observation features appeared most prominently in the 2016 North Korea rocket launch showing a very distinct V-shape rTEC enhancement over enormous areas along the southeast flight trajectory despite that it was also appeared in the 2009 North Korea rocket launch with the eastward flight trajectory. Numerical simulations using the physical-based nonlinear and nonhydrostatic coupled model of neutral atmosphere and ionosphere reproduce promised results in qualitative agreement with the characteristics of ionospheric disturbance waves observed in the 2009 event by considering the released energy of the rocket exhaust as the disturbance source. Simulations reproduce the shock wave signature of electron density enhancement, acoustic wave disturbances, the electron density depletion due to the rocket-induced pressure bulge, and the delayed disturbance waves. The pressure bulge results in outward neutral wind flows carrying neutrals and plasma away from it and leading to electron density depletions. Simulations further show, for the first time, that the delayed disturbance waves are produced by the surface reflection of the earlier arrival acoustic wave disturbances.

  16. Chromosomal aberrations and DNA damage in human populations exposed to the processing of electronics waste.

    Science.gov (United States)

    Liu, Qiang; Cao, Jia; Li, Ke Qiu; Miao, Xu Hong; Li, Guang; Fan, Fei Yue; Zhao, Yong Cheng

    2009-05-01

    It has been known that the pollutants of electronic wastes (E-wastes) can lead to severe pollution to the environment. It has been reported that about 50% to 80% of E-wastes from developed countries are exported to Asia and Africa. It has become a major global environmental problem to deal with 'E-wastes'. E-waste recycling has remained primitive in Jinghai, China. This not only produces enormous environmental pollution but also can bring about toxic or genotoxic effects on the human body, threatening the health of both current residents and future generations living in the local environment. The concentration of lead in the blood of children in the E-waste polluted area in China is higher than that of the control area. But little is known about the cytogenetic effect to human beings caused by the pollution of E-wastes. In the present study, experiments have been performed to investigate the genetics of permanent residents of three villages with numerous E-waste disposal sites and to analyze the harmful effects of exposure to E-wastes. In total, 171 villagers (exposed group) were randomly selected from permanent residents of three villages located in Jinghai County of Tianjin, China, where there has been massive disposal of E-wastes. Thirty villagers were selected from the neighboring towns without E-waste disposal sites to serve as controls. Chromosomal aberrations and cytokinesis blocking micronucleus were performed to detect the cytogenetic effect, dic + r (dicentric and ring chromosome), monomer, fragments (acentric fragments, minute chromosomes, and acentric rings), translocation, satellite, quadriradial, total aberrations, and micronuclear rate were scored for each subject. DNA damage was detected using comet assay; the DNA percentage in the comet tail (TDNA%), tail moment (TM), and Olive tail moment (OTM) were recorded to describe DNA damage to lymphocytes. The total chromosome aberration rates (5.50%) and micronuclear rates (16.99%) of the exposure group

  17. Oxidation of the FAD cofactor to the 8-formyl-derivative in human electron-transferring flavoprotein

    Science.gov (United States)

    Augustin, Peter; Toplak, Marina; Fuchs, Katharina; Gerstmann, Eva Christine; Prassl, Ruth; Winkler, Andreas; Macheroux, Peter

    2018-01-01

    The heterodimeric human (h) electron-transferring flavoprotein (ETF) transfers electrons from at least 13 different flavin dehydrogenases to the mitochondrial respiratory chain through a non-covalently bound FAD cofactor. Here, we describe the discovery of an irreversible and pH-dependent oxidation of the 8α-methyl group to 8-formyl-FAD (8f-FAD), which represents a unique chemical modification of a flavin cofactor in the human flavoproteome. Furthermore, a set of hETF variants revealed that several conserved amino acid residues in the FAD-binding pocket of electron-transferring flavoproteins are required for the conversion to the formyl group. Two of the variants generated in our study, namely αR249C and αT266M, cause glutaric aciduria type II, a severe inherited disease. Both of the variants showed impaired formation of 8f-FAD shedding new light on the potential molecular cause of disease development. Interestingly, the conversion of FAD to 8f-FAD yields a very stable flavin semiquinone that exhibited slightly lower rates of electron transfer in an artificial assay system than hETF containing FAD. In contrast, the formation of 8f-FAD enhanced the affinity to human dimethylglycine dehydrogenase 5-fold, indicating that formation of 8f-FAD modulates the interaction of hETF with client enzymes in the mitochondrial matrix. Thus, we hypothesize that the FAD cofactor bound to hETF is subject to oxidation in the alkaline (pH 8) environment of the mitochondrial matrix, which may modulate electron transport between client dehydrogenases and the respiratory chain. This discovery challenges the current concepts of electron transfer processes in mitochondria. PMID:29301933

  18. Calculation of induced current densities for humans by magnetic fields from electronic article surveillance devices

    Science.gov (United States)

    Gandhi, Om P.; Kang, Gang

    2001-11-01

    This paper illustrates the use of the impedance method to calculate the electric fields and current densities induced in millimetre resolution anatomic models of the human body, namely an adult and 10- and 5-year-old children, for exposure to nonuniform magnetic fields typical of two assumed but representative electronic article surveillance (EAS) devices at 1 and 30 kHz, respectively. The devices assumed for the calculations are a solenoid type magnetic deactivator used at store checkouts and a pass-by panel-type EAS system consisting of two overlapping rectangular current-carrying coils used at entry and exit from a store. The impedance method code is modified to obtain induced current densities averaged over a cross section of 1 cm2 perpendicular to the direction of induced currents. This is done to compare the peak current densities with the limits or the basic restrictions given in the ICNIRP safety guidelines. Because of the stronger magnetic fields at lower heights for both the assumed devices, the peak 1 cm2 area-averaged current densities for the CNS tissues such as the brain and the spinal cord are increasingly larger for smaller models and are the highest for the model of the 5-year-old child. For both the EAS devices, the maximum 1 cm2 area-averaged current densities for the brain of the model of the adult are lower than the ICNIRP safety guideline, but may approach or exceed the ICNIRP basic restrictions for models of 10- and 5-year-old children if sufficiently strong magnetic fields are used.

  19. Calculation of induced current densities for humans by magnetic fields from electronic article surveillance devices.

    Science.gov (United States)

    Gandhi, O P; Kang, G

    2001-11-01

    This paper illustrates the use of the impedance method to calculate the electric fields and current densities induced in millimetre resolution anatomic models of the human body, namely an adult and 10- and 5-year-old children, for exposure to nonuniform magnetic fields typical of two assumed but representative electronic article surveillance (EAS) devices at 1 and 30 kHz, respectively. The devices assumed for the calculations are a solenoid type magnetic deactivator used at store checkouts and a pass-by panel-type EAS system consisting of two overlapping rectangular current-carrying coils used at entry and exit from a store. The impedance method code is modified to obtain induced current densities averaged over a cross section of 1 cm2 perpendicular to the direction of induced currents. This is done to compare the peak current densities with the limits or the basic restrictions given in the ICNIRP safety guidelines. Because of the stronger magnetic fields at lower heights for both the assumed devices, the peak 1 cm2 area-averaged current densities for the CNS tissues such as the brain and the spinal cord are increasingly larger for smaller models and are the highest for the model of the 5-year-old child. For both the EAS devices, the maximum 1 cm2 area-averaged current densities for the brain of the model of the adult are lower than the ICNIRP safety guideline, but may approach or exceed the ICNIRP basic restrictions for models of 10- and 5-year-old children if sufficiently strong magnetic fields are used.

  20. Towards the planning and design of disturbance patterns across scales to counter biological invasions

    Science.gov (United States)

    Giovanni Zurlini; Irene Petrosillo; Kenneth Bruce Jones; Bai-Lian Li; Kurt Hans Riitters; Pietro Medagli; Silvano Marchiori; Nicola Zaccarelli

    2013-01-01

    The way in which disturbances from human land use are patterned in space across scales can have important consequences for efforts to govern human/environment with regard to, but not only, invasive spread-dispersal processes. In this context, we explore the potential of disturbance patterns along a continuum of scales as proxies for identifying the geographical regions...

  1. Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

    2012-07-15

    Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: Black-Right-Pointing-Pointer Electron density of normal and neoplastic breast tissues was measured using Compton scattering. Black-Right-Pointing-Pointer Monochromatic synchrotron radiation was used to obtain the Compton scattering data. Black-Right-Pointing-Pointer The area of Compton peaks was used to determine the electron densities of samples. Black-Right-Pointing-Pointer Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. Black-Right-Pointing-Pointer Comparison with previous results showed differences smaller than 4%.

  2. Influence of high energy electron irradiation and gamma irradiation on the osmotic resistance of human erythrocyte membranes

    International Nuclear Information System (INIS)

    Catana, D.; Hategan, Alina; Moraru, Rodica; Popescu, Alina; Morariu, V. V.

    1998-01-01

    The effects of 5 MeV electrons and of gamma irradiation at 0 deg. C on the osmotic fragility of human erythrocyte membranes are presented. Both electron and gamma radiation in the range 0-400 Gy induced no hemolysis indicating that the membrane modifications due to radiation interaction do not reach a critical point as to cause swelling of the cells and subsequent lysis. The osmotic stress experiments performed after irradiation showed that the gamma irradiated erythrocytes exhibited an almost similar sigmoidal behavior for all irradiation doses, whereas the electron irradiated samples showed a much larger increase in hemolysis degree and, in the case of a given electron dose (100 Gy), the hemolysis was found much smaller than for the control sample (a similar behavior of the erythrocytes was found in the case of microwave irradiation at temperatures under 0 deg. C). Our experimental data suggest that electron radiation and gamma radiation have different impacts on the erythrocyte membrane fluidity, involving, probably, the different rate of energy deposition in the samples and the direct interaction of electrons with the erythrocyte membranes. (authors)

  3. A histomorphometric and scanning electron microscopy study of human condylar cartilage and bone tissue changes in relation to age

    DEFF Research Database (Denmark)

    Paulsen, Hans Ulrik; Thomsen, J.S.; Hougen, Hans Petter

    1999-01-01

    To determine the possibility for adaptive growth in human condyles, quantifying the thickness of fibrocartilage and the constitution of cells with potential activity, the trabecular bone volume, and the structural parameter: marrow space star volume in a larger sample of human autopsy condyles....... EXPERIMENTAL SETTING AND DESIGN: A histomorphometric and scanning electron microscopic analysis of cartilage characteristics and bone remodelling activity. The Departments of Orthodontics and Cell Biology at Aarhus University, Denmark. An autopsy sample of condyles from 20 individuals, 18-31 years of age...

  4. Managing Sleep Disturbances in Cirrhosis

    Directory of Open Access Journals (Sweden)

    Xun Zhao

    2016-01-01

    Full Text Available Sleep disturbances, particularly daytime sleepiness and insomnia, are common problems reported by patients suffering from liver cirrhosis. Poor sleep negatively impacts patients’ quality of life and cognitive functions and increases mortality. Although sleep disturbances can be an early sign of hepatic encephalopathy (HE, many patients without HE still complain of poor quality sleep. The pathophysiology of these disturbances is not fully understood but is believed to be linked to impaired hepatic melatonin metabolism. This paper provides an overview for the clinician of common comorbidities contributing to poor sleep in patients with liver disease, mainly restless leg syndrome and obstructive sleep apnea. It discusses nondrug and pharmacologic treatment options in these patients, such as the use of light therapy and histamine (H1 blockers.

  5. How to make the fourth revolution: Human factors in the adoption of electronic instructional aids

    Science.gov (United States)

    Demerath, N. J.; Daniels, L. A.

    1973-01-01

    The prospects and problems of getting higher education in the United States (high school and above) to more fully utilize electronic technologies are examined. Sociological, psychological, and political factors are analyzed to determine the feasibility of adopting electronic instructional techniques. Differences in organizations, attitudes, and customs of different kinds of students, teachers, administrators, and publics are crucial factors in innovation.

  6. The Disturbing Student and the Judicial Process

    Science.gov (United States)

    Ragle, John D.; Paine, Gage E.

    2009-01-01

    The Assessment-Intervention of Student Problems (AISP) model is a useful tool for preparing student affairs professionals to assess the problems of disturbed, disturbing, or disturbed/disturbing students and to make appropriate referrals. It is particularly useful because it emphasizes the necessity of developing an integrated system for this…

  7. Solar-terrestrial disturbances of June-September 1982, 4

    International Nuclear Information System (INIS)

    Minakoshi, Hisamitsu; Sinno, Kenji; Nishimuta, Ichizo

    1986-01-01

    The ionospheric disturbances observed in and around Japan in association with the severe geomagnetic storm occurring on July 14 - 16, 1982 were investigated by using ionospheric total electron content (N t ) data obtained by the ETS-II beacon experiment and F region data obtained by the soundings at the latitude chain of the ionospheric stations situated nearly along 135 deg E. The most remarkable storm effect was of the negative disturbance, which is common at mid-latitudes in summer. The negative disturbance comprises the decreases in N t and peak electron density (N m ) and a marked increase in slab thickness. In addition, the following interesting events were observed during this storm: (1) sharp depressions in N t and N m occurred almost simultaneously in the regions from mid-latitudes to the equatorial latitude within a few hours after the storm sudden commencement (SSC), (2) some positive disturbances in the F region appeared during the recovery phase of the storm, and were prominent during the night at mid-latitudes and during the daytime at low latitudes, and (3) wavelike fluctuations of N t , which indicate the existence of a mediumscale traveling ionospheric disturbance (TID) with a nearly north to south direction of propagation, were observed during the main phase. (author)

  8. Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation.

    Science.gov (United States)

    Emelyanova, Larisa; Ashary, Zain; Cosic, Milanka; Negmadjanov, Ulugbek; Ross, Gracious; Rizvi, Farhan; Olet, Susan; Kress, David; Sra, Jasbir; Tajik, A Jamil; Holmuhamedov, Ekhson L; Shi, Yang; Jahangir, Arshad

    2016-07-01

    Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF. Copyright © 2016 the American Physiological Society.

  9. Scanning electron microscopy of chronically implanted intracortical microelectrode arrays in non-human primates

    Science.gov (United States)

    Barrese, James C.; Aceros, Juan; Donoghue, John P.

    2016-04-01

    Objective. Signal attenuation is a major problem facing intracortical sensors for chronic neuroprosthetic applications. Many studies suggest that failure is due to gliosis around the electrode tips, however, mechanical and material causes of failure are often overlooked. The purpose of this study was to investigate the factors contributing to progressive signal decline by using scanning electron microscopy (SEM) to visualize structural changes in chronically implanted arrays and histology to examine the tissue response at corresponding implant sites. Approach. We examined eight chronically implanted intracortical microelectrode arrays (MEAs) explanted from non-human primates at times ranging from 37 to 1051 days post-implant. We used SEM, in vivo neural recordings, and histology (GFAP, Iba-1, NeuN). Three MEAs that were never implanted were also imaged as controls. Main results. SEM revealed progressive corrosion of the platinum electrode tips and changes to the underlying silicon. The parylene insulation was prone to cracking and delamination, and in some instances the silicone elastomer also delaminated from the edges of the MEA. Substantial tissue encapsulation was observed and was often seen growing into defects in the platinum and parylene. These material defects became more common as the time in vivo increased. Histology at 37 and 1051 days post-implant showed gliosis, disruption of normal cortical architecture with minimal neuronal loss, and high Iba-1 reactivity, especially within the arachnoid and dura. Electrode tracts were either absent or barely visible in the cortex at 1051 days, but were seen in the fibrotic encapsulation material suggesting that the MEAs were lifted out of the brain. Neural recordings showed a progressive drop in impedance, signal amplitude, and viable channels over time. Significance. These results provide evidence that signal loss in MEAs is truly multifactorial. Gliosis occurs in the first few months after implantation but does

  10. Forest disturbances under climate change

    Czech Academy of Sciences Publication Activity Database

    Seidl, R.; Thom, D.; Kautz, M.; Martin-Benito, D.; Peltoniemi, M.; Vacchiano, G.; Wild, Jan; Ascoli, D.; Petr, M.; Honkaniemi, J.; Lexer, M. J.; Trotsiuk, V.; Mairota, P.; Svoboda, M.; Fabrika, M.; Nagel, T.A.; Reyer, C. P. O.

    2017-01-01

    Roč. 7, č. 6 (2017), s. 395-402 ISSN 1758-678X R&D Projects: GA MŠk(CZ) LD15158 Institutional support: RVO:67985939 Keywords : climate change * disturbance * forest Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 19.304, year: 2016

  11. Gastrointestinal disturbances in marathon runners.

    Science.gov (United States)

    Riddoch, C; Trinick, T

    1988-06-01

    The purpose of this survey was to investigate the prevalence of running-induced gastrointestinal (GI) disturbances in marathon runners. A questionnaire was completed by 471 of the estimated 1,750 competitors in the 1986 Belfast City Marathon. Eighty-three per cent of respondents indicated that they occasionally or frequently suffered one or more GI disturbances during or immediately after running. The urge to have a bowel movement (53%) and diarrhoea (38%) were the most common symptoms, especially among female runners (74% and 68% respectively). Upper GI tract symptoms were experienced more by women than men (p less than 0.05) and more by younger runners than older runners (p less than 0.01). Women also suffered more lower GI tract symptoms than men (p less than 0.05) with younger runners showing a similar trend. Both upper and lower tract symptoms were more common during a "hard" run than an "easy" run (p less than 0.01) and were equally as common both during and after running. Of those runners who suffered GI disturbances, 72% thought that running was the cause and 29% believed their performance to be adversely affected. There was no consensus among sufferers as to the causes of symptoms and a wide variety of "remedies" were suggested. GI disturbances are common amongst long-distance runners and their aetiology is unknown. Medical practitioners should be aware of this when dealing with patients who run.

  12. Nicotine and the Developing Human: A Neglected Element in the Electronic Cigarette Debate

    OpenAIRE

    England, Lucinda J.; Bunnell, Rebecca E.; Pechacek, Terry F.; Tong, Van T.; McAfee, Tim A.

    2015-01-01

    The elimination of cigarettes and other combusted tobacco products in the U.S. would prevent tens of millions of tobacco-related deaths. It has been suggested that the introduction of less harmful nicotine delivery devices, such as electronic cigarettes or other electronic nicotine delivery systems, will accelerate progress toward ending combustible cigarette use. However, careful consideration of the potential adverse health effects from nicotine itself is often absent from public health deb...

  13. MANAGING HUMAN FACTORS IN IMPLEMENTING ELECTRONIC DOCUMENT SYSTEM IN THE PUBLIC SECTOR

    Directory of Open Access Journals (Sweden)

    TOMS LEIKUMS

    2012-05-01

    Full Text Available Document management underlies the activities of almost every organization. Correctly managed correspondence and organized document circulation characterize successful performance particularly in the public sector organizations. Even though production of documents itself is not the main task of governmental institutions, document creation and processing are crucial processes for the provision of basic functions in public sector. In the 21st century it gets more important to use the new possibilities offered by modern technologies, including electronic document management. Public sector itself is a heavy bureaucratic apparatus in the need of elasticity and ability to change its working processes and habits in order to gradually switch to the digital environment. Western European countries have already turned to electronic document management whilst most of the Eastern European countries, including Latvia, have just recently started a gradual electronization of document circulation. When implementing electronic document management systems in the public sector organizations, it often comes to resistance of the staff and unwillingness to change the accustomed methods of work – paper format document circulation. Both lower level staff and higher level managers put obstacles to electronic document management. In this article author inspects cases of successful practice and analyses possible action mechanisms that could convince public sector personnel of advantages of electronic document circulation and prepare them to switch to work with digital documents.

  14. Electron beam inactivation of Tulane virus on fresh produce, and mechanism of inactivation of human norovirus surrogates by electron beam irradiation.

    Science.gov (United States)

    Predmore, Ashley; Sanglay, Gabriel C; DiCaprio, Erin; Li, Jianrong; Uribe, R M; Lee, Ken

    2015-04-02

    Ionizing radiation, whether by electron beams or gamma rays, is a non-thermal processing technique used to improve the microbial safety and shelf-life of many different food products. This technology is highly effective against bacterial pathogens, but data on its effect against foodborne viruses is limited. A mechanism of viral inactivation has been proposed with gamma irradiation, but no published study discloses a mechanism for electron beam (e-beam). This study had three distinct goals: 1) evaluate the sensitivity of a human norovirus surrogate, Tulane virus (TV), to e-beam irradiation in foods, 2) compare the difference in sensitivity of TV and murine norovirus (MNV-1) to e-beam irradiation, and 3) determine the mechanism of inactivation of these two viruses by e-beam irradiation. TV was reduced from 7 log10 units to undetectable levels at target doses of 16 kGy or higher in two food matrices (strawberries and lettuce). MNV-1 was more resistant to e-beam treatment than TV. At target doses of 4 kGy, e-beam provided a 1.6 and 1.2 log reduction of MNV-1 in phosphate buffered saline (PBS) and Dulbecco's Modified Eagle Medium (DMEM), compared to a 1.5 and 1.8 log reduction of TV in PBS and Opti-MEM, respectively. Transmission electron microscopy revealed that increased e-beam doses negatively affected the structure of both viruses. Analysis of viral proteins by SDS-PAGE found that irradiation also degraded viral proteins. Using RT-PCR, irradiation was shown to degrade viral genomic RNA. This suggests that the mechanism of inactivation of e-beam was likely the same as gamma irradiation as the damage to viral constituents led to inactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Using landscape disturbance and succession models to support forest management

    Science.gov (United States)

    Eric J. Gustafson; Brian R. Sturtevant; Anatoly S. Shvidenko; Robert M. Scheller

    2010-01-01

    Managers of forested landscapes must account for multiple, interacting ecological processes operating at broad spatial and temporal scales. These interactions can be of such complexity that predictions of future forest ecosystem states are beyond the analytical capability of the human mind. Landscape disturbance and succession models (LDSM) are predictive and...

  16. Differential reactions to anthropogenic disturbance by two ground ...

    African Journals Online (AJOL)

    Both ABO and KG significantly altered their behavioural responses to disturbance from pre-breeding to breeding. These results emphasise the need to have a buffer zone surrounding breeding areas excluding human presence to allow for the successful breeding of ABO. Keywords: African Black Oystercatcher, buffer zone, ...

  17. The disturbance-diversity relationship: integrating biodiversity conservation and resource management in anthropogenic landscapes

    OpenAIRE

    Sharma, Lila Nath

    2016-01-01

    Disturbance, natural or anthropogenic, is ubiquitous to forest and grassland ecosystems across the globe. Many of these ecosystems have evolved alongside centuries old anthropogenic disturbance regimes. Understanding how disturbance impacts biodiversity and ecosystem service delivery is a topic of paramount importance as high biodiversity is likely to provide a wide array of ecosystem goods and services to an ever-growing human population. There is a general consensus that dist...

  18. Thermal analysis of epidermal electronic devices integrated with human skin considering the effects of interfacial thermal resistance

    Science.gov (United States)

    Li, Yuhang; Zhang, Jianpeng; Xing, Yufeng; Song, Jizhou

    2018-05-01

    Epidermal electronic devices (EEDs) have similar mechanical properties as those of human skin such that they can be integrated with human skin for potential applications in monitoring of human vital signs for diagnostic, therapeutic or surgical functions. Thermal management is critical for EEDs in these applications since excessive heating may cause discomfort. Comprehensive analytical studies, finite element analysis and experiments are carried out to study the effects of interfacial thermal resistance between EEDs and human skin on thermal properties of the EED/skin system in this paper. The coupling between the Fourier heat transfer in EEDs and the bio-heat transfer in human skin is accounted in the analytical model based on the transfer matrix method to give accurate predictions on temperatures, which agree well with finite element analysis and experimental measurements. It is shown that the maximum temperature increase of the EED for the case of imperfect bonding between EED and skin is much higher than that of perfect bonding. These results may help the design of EEDs in bi-integrated applications and suggest a valuable route to evaluate the bonding condition between EEDs and biological tissues.

  19. Disturbances in small bowel motility.

    LENUS (Irish Health Repository)

    Quigley, E M

    2012-02-03

    Recently, the small intestine has become the focus of investigation as a potential site of dysmotility in the irritable bowel syndrome (IBS). A number of motor abnormalities have been defined in some studies, and include \\'clustered\\' contractions, exaggerated post-prandial motor response and disturbances in intestinal transit. The significance of these findings remains unclear. The interpretation of available studies is complicated by differences in subject selection, the direct influence of certain symptoms, such as diarrhoea and constipation, and the interference of compounding factors, such as stress and psychopathology. Dysmotility could also reflect autonomic dysfunction, disturbed CNS control and the response to heightened visceral sensation or central perception. While motor abnormalities may not explain all symptoms in IBS, sensorimotor interactions may be important in symptom pathogenesis and deserve further study.

  20. Diagnosis of early human myocardial ischemic damage with electron probe microanalysis

    International Nuclear Information System (INIS)

    Singh, S.; Abraham, J.L.; Raasch, F.; Wolf, P.; Bloor, C.M.

    1983-01-01

    We determined the Na/K x-ray intensity ratio in frozen sections of myocardial tissues obtained at autopsy from patients who died from various causes, using electron probe analysis. We have been able to distinguish between the ischemically injured and normal cells. The method is simple, fast, and dependable even when the duration of ischemia is only 30 minutes

  1. Ultrastructural changes following electron irradiation in three-dimensional culture of normal human dermal fibroblasts

    International Nuclear Information System (INIS)

    Han, Chunmao; Ishikura, Naotaka; Tsukada, Sadao

    1994-01-01

    The present study was designed to examine the effect of electron irradiation on fibroblasts and extracellular matrices electron-microscopically. The three-dimensional dermal fibroblast culture was exposed to one, 4 or 10 Gy of electron beams. One day after irradiation, fibroblasts were vacuolated in all irradiated groups and intercellular spaces were increased in a dose-dependent manner. Seven days later, intercellular spaces became dense in both one and 4 Gy groups, although they were still extremely increased in the 10 Gy group. The remaining fibroblasts were still activated in all groups. Thirty days after irradiation, myofibroblastic cells were scarcely observed, but extracellular fine fibrils and collagen fibrils were observed in all irradiated groups. The other ultrastructural findings were similar to those in the control group. In conclusion, electron beams damaged not only cells but also extracellular matrix. The extracellular matrix may be repaired by activated residual fibroblasts, resulting in the mixture of new and old collagen fibrils having different diamters. (N.K.)

  2. Postradiation disturbances of neuroendocrinal interaction

    International Nuclear Information System (INIS)

    Dedov, V.I.

    1980-01-01

    Analysis of data on the disturbances induced by ionizing irradiation in endocrine organs is given on the basis of experimental material. Mechanism and dynamics of the radiation pathology of such organs of endocrine system as hypothalamus, hypophysis, adrenal glands, thyroid, gonads are considered. Necessity of the determination of criteria of injury significance and study of delayed effects of ionizing radiation in perspective investigation of the problems of endocrine radiation pathology is pointed out

  3. Mechanical disturbances in superconducting magnets

    International Nuclear Information System (INIS)

    Sugimoto, Makoto

    1990-03-01

    The stress distribution in a small epoxy-impregnated Nb 3 Sn coil was calculated by the finite element method. Mechanical disturbances due to the electromagnetic force in the magnet are discussed. The coil stability in relation with the stress distribution is also discussed by using the experimental results. To evaluate such stresses, a calculation model was investigated. It was found that the model, which removed the internal bore element in the model magnet, gave a reasonable condition to estimate to stress. A quench mechanism due to mechanical disturbances in superconducting magnets is discussed. According to this mechanism, an internal slit was assumed as the reason for the mechanical disturbance. The internal slit is generated at the boundary between the superconductor and the bore element by the thermally induced stress. When charging a magnet, the induced electromagnetic force results in a stress concentration at the slit, and hence to an enlargement of it. During the enlargement of the internal slit, heat is generated at the top of it. Such heat generation from a mechanical disturbance can induce a quench. Through these investigations, the following coil manufacturing method can be proposed to reduce such stresses: the magnet should be manufactured to separate the bore element from the superconductor and this separation technique can reduce the boundary stress during cool-down. Actually, a thin teflon film at the boundary between the superconductor and the bore element can be used as a separator. Another separation technique is a teflon coating on the internal bore element. The separation technique should result in a stable epoxy-impregnated superconducting magnet. (J.P.N.)

  4. A Comparative Analysis for Selection of Appropriate Mother Wavelet for Detection of Stationary Disturbances

    Science.gov (United States)

    Kamble, Saurabh Prakash; Thawkar, Shashank; Gaikwad, Vinayak G.; Kothari, D. P.

    2017-12-01

    Detection of disturbances is the first step of mitigation. Power electronics plays a crucial role in modern power system which makes system operation efficient but it also bring stationary disturbances in the power system and added impurities to the supply. It happens because of the non-linear loads used in modern day power system which inject disturbances like harmonic disturbances, flickers, sag etc. in power grid. These impurities can damage equipments so it is necessary to mitigate these impurities present in the supply very quickly. So, digital signal processing techniques are incorporated for detection purpose. Signal processing techniques like fast Fourier transform, short-time Fourier transform, Wavelet transform etc. are widely used for the detection of disturbances. Among all, wavelet transform is widely used because of its better detection capabilities. But, which mother wavelet has to use for detection is still a mystery. Depending upon the periodicity, the disturbances are classified as stationary and non-stationary disturbances. This paper presents the importance of selection of mother wavelet for analyzing stationary disturbances using discrete wavelet transform. Signals with stationary disturbances of various frequencies are generated using MATLAB. The analysis of these signals is done using various mother wavelets like Daubechies and bi-orthogonal wavelets and the measured root mean square value of stationary disturbance is obtained. The measured value obtained by discrete wavelet transform is compared with the exact RMS value of the frequency component and the percentage differences are presented which helps to select optimum mother wavelet.

  5. Electron microscopic in situ hybridization and autoradiography: Localization and transcription of rDNA in human lymphocyte nucleoli

    International Nuclear Information System (INIS)

    Wachtler, F.; Mosgoeller, W.S.; Schwarzacher, H.G.

    1990-01-01

    The distribution of ribosomal DNA (rDNA) in the nucleoli of human lymphocytes was revealed by in situ hybridization with a nonautoradiographic procedure at the electron microscopic level. rDNA is located in the dense fibrillar component of the nucleolus but not in the fibrillar centers. In the same cells the incorporation of tritiated uridine takes place in the dense fibrillar component of the nucleolus as seen by autoradiography followed by gold latensification. From these findings it can be concluded that the transcription of ribosomal DNA takes place in the dense fibrillar component of the nucleolus

  6. Information-disturbance tradeoff in quantum measurements

    International Nuclear Information System (INIS)

    Maccone, Lorenzo

    2006-01-01

    We present a simple information-disturbance tradeoff relation valid for any general measurement apparatus: The disturbance between input and output states is lower bounded by the information the apparatus provides in distinguishing these two states

  7. Solar-terrestrial disturbances of June-September 1982, 4

    International Nuclear Information System (INIS)

    Minakoshi, Hisamitsu; Sinno, Kenji; Nishimuta, Ichizo

    1985-01-01

    The ionospheric disturbances around Japan associated with the severe magnetic storm on July 14-16, 1982 were investigated using ionospheric total electron content (Nsub(t)) data obtained by the ETS-II beacon experiment and F-region data obtained by the soundings at the latitude chain of the ionospheric stations situated nearly along 135 0 E. The most remarkable storm effects were the negative disturbances, which are common at mid-latitudes in summer. The negative disturbances comprise decreases in Nsub(t) and peak electron density (Nsub(m)) and a marked increase in slab thickness. In addition, the following interesting events were observed during this storm: (1) sharp decreases in Nsub(t) and Nsub(m) occurred almost simultaneously in the regions from mid-latitudes to the equatorial latitude within a few hours after the storm sudden commencement (SSC), (2) some positive disturbances in the F-region appeared during the last phase of the storm, which were prominent at mid-latitudes during the night and at low-latitudes in the afternoon, and (3) a medium-scale traveling ionospheric distubance (TID) with a nearly north to south direction of propagation was observed as wavelike fluctuations of Nsub(t). (author)

  8. Dose conversion coefficients for electron exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G; Zankl, M

    2009-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H p (0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H p (3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 deg. and 45 deg. are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  9. Human Powered PiezoelectricBatteries to Supply Power to Wearable Electronic Devices.

    OpenAIRE

    Gonzalez, Jose' Luis; Rubio, Antonio; Moll, Francesc

    2002-01-01

    Consumer electronic equipments are becoming small, portable devices that provide users with a wide range of functionality, from communication to music playing. The battery technology and the power consumption of the device limit the size, weight and autonomous lifetime. One promising alternative to batteries (and fuel cells, that must be refueled as well) is to use the parasitic energy dissipated in the movement of the wearer of the device to power it. We analyze in this work the current stat...

  10. Maximal thickness of the normal human pericardium assessed by electron-beam computed tomography

    International Nuclear Information System (INIS)

    Delille, J.P.; Hernigou, A.; Sene, V.; Chatellier, G.; Boudeville, J.C.; Challande, P.; Plainfosse, M.C.

    1999-01-01

    The purpose of this study was to determine the maximal value of normal pericardial thickness with an electron-beam computed tomography unit allowing fast scan times of 100 ms to reduce cardiac motion artifacts. Electron-beam computed tomography was performed in 260 patients with hypercholesterolemia and/or hypertension, as these pathologies have no effect on pericardial thickness. The pixel size was 0.5 mm. Measurements could be performed in front of the right ventricle, the right atrioventricular groove, the right atrium, the left ventricle, and the interventricular groove. Maximal thickness of normal pericardium was defined at the 95th percentile. Inter-observer and intra-observer reproducibility studies were assessed from additional CT scans by the Bland and Altman method [24]. The maximal thickness of the normal pericardium was 2 mm for 95 % of cases. For the reproducibility studies, there was no significant relationship between the inter-observer and intra-observer measurements, but all pericardial thickness measurements were ≤ 1.6 mm. Using electron-beam computed tomography, which assists in decreasing substantially cardiac motion artifacts, the threshold of detection of thickened pericardium is statistically established as being 2 mm for 95 % of the patients with hypercholesterolemia and/or hypertension. However, the spatial resolution available prevents a reproducible measure of the real thickness of thin pericardium. (orig.)

  11. Maximal thickness of the normal human pericardium assessed by electron-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Delille, J.P.; Hernigou, A.; Sene, V.; Chatellier, G.; Boudeville, J.C.; Challande, P.; Plainfosse, M.C. [Service de Radiologie Centrale, Hopital Broussais, Paris (France)

    1999-08-01

    The purpose of this study was to determine the maximal value of normal pericardial thickness with an electron-beam computed tomography unit allowing fast scan times of 100 ms to reduce cardiac motion artifacts. Electron-beam computed tomography was performed in 260 patients with hypercholesterolemia and/or hypertension, as these pathologies have no effect on pericardial thickness. The pixel size was 0.5 mm. Measurements could be performed in front of the right ventricle, the right atrioventricular groove, the right atrium, the left ventricle, and the interventricular groove. Maximal thickness of normal pericardium was defined at the 95th percentile. Inter-observer and intra-observer reproducibility studies were assessed from additional CT scans by the Bland and Altman method [24]. The maximal thickness of the normal pericardium was 2 mm for 95 % of cases. For the reproducibility studies, there was no significant relationship between the inter-observer and intra-observer measurements, but all pericardial thickness measurements were {<=} 1.6 mm. Using electron-beam computed tomography, which assists in decreasing substantially cardiac motion artifacts, the threshold of detection of thickened pericardium is statistically established as being 2 mm for 95 % of the patients with hypercholesterolemia and/or hypertension. However, the spatial resolution available prevents a reproducible measure of the real thickness of thin pericardium. (orig.) With 6 figs., 1 tab., 31 refs.

  12. The level of the usage of the human resource information system and electronic recruitment in Croatian companies

    Directory of Open Access Journals (Sweden)

    Snježana Pivac

    2014-12-01

    Full Text Available Performing business according to contemporary requirements influences companies for continuous usage of modern managerial tools, such as a human resource information system (HRIS and electronic recruitment (ER. Human resources have been recognised as curtail resources and the main source of a competitive advantage in creation of successful business performance. In order to attract and select the top employees, companies use quality information software for attracting internal ones, and electronic recruitment for attracting the best possible external candidates. The main aim of this paper is to research the level of the usage of HRIS and ER within medium-size and large Croatian companies. Moreover, the additional aim of this paper is to evaluate the relationship among the usage of these modern managerial tools and the overall success of human resource management within these companies. For the purpose of this paper, primary and secondary research has been conducted in order to reveal the level of the usage of HRIS and ER as well as the overall success of human resource management in Croatian companies. The companies’ classification (HRIS and ER is done by using the non-hierarchical k-means cluster method as well as the nonparametric Kruskal Wallis test. Further, the companies are ranked by the multicriteria PROMETHEE method. Relevant nonparametric tests are used for testing the overall companies’ HRM. Finally, binary logistic regression is estimated, relating binary variable HRM and HRIS development. After detailed research, it can be concluded that large Croatian companies apply HRIS in majority (with a positive relation to HRM performance, but still require certain degrees of its development.

  13. Managing forest disturbances and community responses: lessons from the Kenai Peninsula, Alaska.

    Science.gov (United States)

    Courtney G. Flint; Richard. Haynes

    2006-01-01

    Managing forest disturbances can be complicated by diverse human community responses. Interview and quantitative analysis of mail surveys were used to assess risk perceptions and community actions in response to forest disturbance by spruce bark beetles. Despite high risk perception of immediate threats to personal safety and property, risk perceptions of broader...

  14. Spatial and temporal dynamics of disturbance interactions along an ecological gradient

    Science.gov (United States)

    Christopher D. O' Connor

    2013-01-01

    Interactions among site conditions, disturbance events, and climate determine the patterns of forest species recruitment and mortality across landscapes. Forests of the American Southwest have undergone significant changes over a century of altered disturbance regimes, human land uses, and changing environmental conditions. Along steep vertical gradients such as those...

  15. Consequences of climate change for biotic disturbances in North American forests

    Science.gov (United States)

    Aaron S. Weed; Matthew P. Ayres; Jeffrey A. Hicke

    2013-01-01

    About one-third of North America is forested. These forests are of incalculable value to human society in terms of harvested resources and ecosystem services and are sensitive to disturbance regimes. Epidemics of forest insects and diseases are the dominant sources of disturbance to North American forests. Here we review current understanding of climatic effects...

  16. Disturbance Decoupling of Switched Linear Systems

    NARCIS (Netherlands)

    Yurtseven, E.; Heemels, W.P.M.H.; Camlibel, M.K.

    2010-01-01

    In this paper we consider disturbance decoupling problems for switched linear systems. We will provide necessary and sufficient conditions for three different versions of disturbance decoupling, which differ based on which signals are considered to be the disturbance. In the first version the

  17. Local habitat disturbance increases bird nest predation in the Brazilian Atlantic rainforest

    Directory of Open Access Journals (Sweden)

    Rodrigues, V. B.

    2018-01-01

    Full Text Available We evaluated the effect of anthropogenic disturbance on nest predation in Brazilian Atlantic forest. Artificial nests were distributed in fragments with distinct degrees of anthropogenic disturbance. We found a higher proportion of egg predation on the ground and in the fragments classified as ‘high’ and ‘medium’ disturbance than in the fragments classified as ‘low’ degree of disturbance. The higher egg predation is probably linked to low structural complexity of vegetation and high accessibility of these areas to opportunistic predators. We suggest that forest fragments with high vegetation complexity and low human activity should be preserved in order to maintain the biodiversity of bird species.

  18. Designing a model of electronic human resource management’s implementation at the Ministry of Communications and Information Technology

    Directory of Open Access Journals (Sweden)

    Mirali Seyednaghavi

    2017-06-01

    Full Text Available : In the first phase of this study a model for electronic human resource management in government agencies based on new public services was explored by using software MAXQDA, then in the second phase, relationship between the elements of the theory were tested using software Smart PLS2. So the aim of this study is to design a model of electronic human resource management’s implementation at the Ministry of Communications and Information Technology. In this regard, according to Strauss and Corbin’s structured plan, five hypotheses were tested. Quantitative data analysis indicates that the pressures of the policies and global perspectives cause to move toward e-HRM. Among the contextual conditions macro structural mechanisms, considerations of actors, governance considerations have a significant impact on the strategy of new public services and therefore lead to the consequences of its implementation in public organizations. The findings suggest that e-HRM does not have a positive and meaningful impact on new public services, and in our country, although the recent political developments have somehow removed the gap between public policy makers, administrators, and the public, but there is still a long way to go.

  19. Use of scalp hair as indicator of human exposure to heavy metals in an electronic waste recycling area

    International Nuclear Information System (INIS)

    Wang Thanh; Fu Jianjie; Wang Yawei; Liao Chunyang; Tao Yongqing; Jiang Guibin

    2009-01-01

    Scalp hair samples were collected at an electronic waste (e-waste) recycling area and analyzed for trace elements and heavy metals. Elevated levels were found for Cu and Pb with geometric means (GMs) at 39.8 and 49.5 μg/g, and the levels of all elements were found in the rank order Pb > Cu >> Mn > Ba > Cr > Ni > Cd > As > V. Besides Cu and Pb, Cd (GM: 0.518 μg/g) was also found to be significantly higher compared to that in hair samples from control areas. Differences with age, gender, residence status and villages could be distinguished for most of the elements. The high levels of Cd, Cu and Pb were likely found to be originated from e-waste related activities, and specific sources were discussed. This study shows that human scalp hair could be a useful biomarker to assess the extent of heavy metal exposure to workers and residents in areas with intensive e-waste recycling activities. - Human scalp hair samples can be used to indicate environmental and occupational exposure of heavy metals due to intensive electronic waste recycling activities.

  20. Dose-response relationship for chromosomal aberrations induced in human lymphocytes by 18 MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Lashin, E.A.; Elaasar, E.M.; Moustafa, H.F.; Bakir, Y.Y.; Al Zenki, S.D.

    1990-01-01

    Dose response curves for lymphocyte chromosome aberration frequencies using X- and gamma radiation became an important and reliable indicator as biological dosimeter especially in radiation accidents and occupational over exposures. Nowadays electron beam therapy is frequently used for their advantages in cases of tumours under or near to the body surface. Dose-response curves for these electron beams are rarely published. Human peripheral blood lymphocytes were in vitro irradiated with various low and high doses (0.1 Gy to 4.9 Gy) of 18 MeV electron beams to utilize such a dose-response curve using chromosomal aberration frequencies as a biological indicator. Then we compared the biological curve with physically obtained curves normally used in planning for radiotherapy treatment. It is interesting to find a significant difference between both of them. The biological curve is generally higher in value and the aberrations induced by 93% of a dose is significantly higher and deeper in site than those aberrations induced by the 100% dose calculated physically. If the above observation is confirmed by detailed studies, it would be of importance to the radiotherapist to plan for isodose curves according to biological determinations. (author)

  1. Preservation of protein fluorescence in embedded human dendritic cells for targeted 3D light and electron microscopy.

    Science.gov (United States)

    Höhn, K; Fuchs, J; Fröber, A; Kirmse, R; Glass, B; Anders-Össwein, M; Walther, P; Kräusslich, H-G; Dietrich, C

    2015-08-01

    In this study, we present a correlative microscopy workflow to combine detailed 3D fluorescence light microscopy data with ultrastructural information gained by 3D focused ion beam assisted scanning electron microscopy. The workflow is based on an optimized high pressure freezing/freeze substitution protocol that preserves good ultrastructural detail along with retaining the fluorescence signal in the resin embedded specimens. Consequently, cellular structures of interest can readily be identified and imaged by state of the art 3D confocal fluorescence microscopy and are precisely referenced with respect to an imprinted coordinate system on the surface of the resin block. This allows precise guidance of the focused ion beam assisted scanning electron microscopy and limits the volume to be imaged to the structure of interest. This, in turn, minimizes the total acquisition time necessary to conduct the time consuming ultrastructural scanning electron microscope imaging while eliminating the risk to miss parts of the target structure. We illustrate the value of this workflow for targeting virus compartments, which are formed in HIV-pulsed mature human dendritic cells. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  2. Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals.

    Science.gov (United States)

    Wang, Xuewen; Gu, Yang; Xiong, Zuoping; Cui, Zheng; Zhang, Ting

    2014-03-05

    Flexible and transparent E-skin devices are achieved by combining silk-molded micro-patterned polydimethylsiloxane (PDMS) with single-walled carbon nanotube (SWNT) ultrathin films. The E-skin sensing device demonstrates superior sensitivity, a very low detectable pressure limit, a fast response time, and a high stability for the detection of superslight pressures, which may broaden their potential use as cost-effective wearable electronics for healthcare applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Remote sensing of forest insect disturbances: Current state and future directions.

    Science.gov (United States)

    Senf, Cornelius; Seidl, Rupert; Hostert, Patrick

    2017-08-01

    Insect disturbance are important agents of change in forest ecosystems around the globe, yet their spatial and temporal distribution and dynamics are not well understood. Remote sensing has gained much attention in mapping and understanding insect outbreak dynamics. Consequently, we here review the current literature on the remote sensing of insect disturbances. We suggest to group studies into three insect types: bark beetles, broadleaved defoliators, and coniferous defoliators. By so doing, we systematically compare the sensors and methods used for mapping insect disturbances within and across insect types. Results suggest that there are substantial differences between methods used for mapping bark beetles and defoliators, and between methods used for mapping broadleaved and coniferous defoliators. Following from this, we highlight approaches that are particularly suited for each insect type. Finally, we conclude by highlighting future research directions for remote sensing of insect disturbances. In particular, we suggest to: 1) Separate insect disturbances from other agents; 2) Extend the spatial and temporal domain of analysis; 3) Make use of dense time series; 4) Operationalize near-real time monitoring of insect disturbances; 5) Identify insect disturbances in the context of coupled human-natural systems; and 6) Improve reference data for assessing insect disturbances. Since the remote sensing of insect disturbances has gained much interest beyond the remote sensing community recently, the future developments identified here will help integrating remote sensing products into operational forest management. Furthermore, an improved spatiotemporal quantification of insect disturbances will support an inclusion of these processes into regional to global ecosystem models.

  4. Development of an Electronic Kit for detecting asthma in Human Respiratory System

    Science.gov (United States)

    Shek Hong, Cheow; Ghani, Ahmad Shahrizan Abdul; Khairuddin, Ismail Mohd

    2018-03-01

    In this paper, a prototype of a carbon dioxide (CO2) measurement device is designed to detect and used to monitor asthma patients. Nowadays, capnogram device is widely used in monitoring asthma and asthma related medical services. However, capnogram is very costly and unaffordable for patient especially those who are in low income household. Thus, the proposed device is cost effective, affordable, and produced to detect and monitor the severity of asthma. Meanwhile, flow meter will cause patient to have chest pain as they needed maximum effort to blow in the device. To overcome these limitations, this prototype electronic kit is easy to use and suitable for all range patients. This prototype electronic kit consists of MH-Z14A carbon dioxide (CO2) sensor to detect the concentration of carbon dioxide from the user exhaled air. Arduino microcontroller is used to process the data while TFT Display shield is applied for data presentation. In addition, HC-06 Bluetooth module is used to communicate with PC for further analysis of the captured graph. This device was tested with 3 asthmatics and 3 normal users. The results showed that asthmatic user has a different graph pattern compared with normal user and these graphs are clearly differentiated on the device TFT screen. Asthmatic user produces “shark fin”-like pattern whereas normal user produces “square wave”-like pattern. This device has successfully produced distinguished-patterns difference between asthmatic and normal user; therefore, it is suitable for asthma monitoring.

  5. Electron probe study of human and red deer cementum and root dentin

    Energy Technology Data Exchange (ETDEWEB)

    Toetdal, B. (Department of Physics, University of Trondheim, The Norwegian Institute of Technology); Hals, E. (Department of Cariology and Endodontics, Faculty of Odontology, University of Bergen, Norway)

    1985-01-01

    A topographical description of the concentration profiles of Ca, P, Mg, Zn, F, S, and K in human and red deer cementum and root dentin is given. The concentrations reported should be regarded as semiquantitative values. A downward slope of the Ca, P, and Mg profiles toward the pulpal cavity seemed largely to correspond with the secondary dentin. Marked elevations of the Zn profiles, modest elevations of the F profiles, and in a few instances of the S profiles, toward root surface and pulpal cavity were registered. In a couple of scans a slight elevation of the K profile toward the root surface was observed. A high degree of concordance in human and red deer teeth was ascertained.

  6. Electron Pathways through Erythrocyte Plasma Membrane in Human Physiology and Pathology: Potential Redox Biomarker?

    OpenAIRE

    Matteucci, Elena; Giampietro, Ottavio

    2007-01-01

    Erythrocytes are involved in the transport of oxygen and carbon dioxide in the body. Since pH is the influential factor in the Bohr-Haldane effect, pHi is actively maintained via secondary active transports Na+/H+ exchange and HC3 -/Cl- anion exchanger. Because of the redox properties of the iron, hemoglobin generates reactive oxygen species and thus, the human erythrocyte is constantly exposed to oxidative damage. Although the adult erythrocyte lacks protein synthesis and cannot restore dama...

  7. Implications of recurrent disturbance for genetic diversity.

    Science.gov (United States)

    Davies, Ian D; Cary, Geoffrey J; Landguth, Erin L; Lindenmayer, David B; Banks, Sam C

    2016-02-01

    Exploring interactions between ecological disturbance, species' abundances and community composition provides critical insights for ecological dynamics. While disturbance is also potentially an important driver of landscape genetic patterns, the mechanisms by which these patterns may arise by selective and neutral processes are not well-understood. We used simulation to evaluate the relative importance of disturbance regime components, and their interaction with demographic and dispersal processes, on the distribution of genetic diversity across landscapes. We investigated genetic impacts of variation in key components of disturbance regimes and spatial patterns that are likely to respond to climate change and land management, including disturbance size, frequency, and severity. The influence of disturbance was mediated by dispersal distance and, to a limited extent, by birth rate. Nevertheless, all three disturbance regime components strongly influenced spatial and temporal patterns of genetic diversity within subpopulations, and were associated with changes in genetic structure. Furthermore, disturbance-induced changes in temporal population dynamics and the spatial distribution of populations across the landscape resulted in disrupted isolation by distance patterns among populations. Our results show that forecast changes in disturbance regimes have the potential to cause major changes to the distribution of genetic diversity within and among populations. We highlight likely scenarios under which future changes to disturbance size, severity, or frequency will have the strongest impacts on population genetic patterns. In addition, our results have implications for the inference of biological processes from genetic data, because the effects of dispersal on genetic patterns were strongly mediated by disturbance regimes.

  8. Nano-analytical electron microscopy reveals fundamental insights into human cardiovascular tissue calcification

    Science.gov (United States)

    Bertazzo, Sergio; Gentleman, Eileen; Cloyd, Kristy L.; Chester, Adrian H.; Yacoub, Magdi H.; Stevens, Molly M.

    2013-06-01

    The accumulation of calcified material in cardiovascular tissue is thought to involve cytochemical, extracellular matrix and systemic signals; however, its precise composition and nanoscale architecture remain largely unexplored. Using nano-analytical electron microscopy techniques, we examined valves, aortae and coronary arteries from patients with and without calcific cardiovascular disease and detected spherical calcium phosphate particles, regardless of the presence of calcific lesions. We also examined lesions after sectioning with a focused ion beam and found that the spherical particles are composed of highly crystalline hydroxyapatite that crystallographically and structurally differs from bone mineral. Taken together, these data suggest that mineralized spherical particles may play a fundamental role in calcific lesion formation. Their ubiquitous presence in varied cardiovascular tissues and from patients with a spectrum of diseases further suggests that lesion formation may follow a common process. Indeed, applying materials science techniques to ectopic and orthotopic calcification has great potential to lend critical insights into pathophysiological processes underlying calcific cardiovascular disease.

  9. Electron microscope studies of methotrexate and radiation effects in human squamous cell carcinoma of the mouth

    International Nuclear Information System (INIS)

    De Martino, C.

    1974-01-01

    Serial biopsy specimens from two squamous cell carcinomas of the mouth were studied by electron microscopy. This report described the ultrastructural changes in the cells produced by treatment with methotrexate followed by irradiation. The main ultrastructural findings after treatment are: numerous autophagic lysosomes and residual bodies are visible in the cytoplasm of the tumor cells; mitochondria are swollen. The mitochondrial cristae are distorted and disrupted, and mitochondrial matrix disappears; the nucleolus shows a series of morphological changes such as development of a compact nucleolus, aggregation of granular elements, atrophy, dissolution and fragmentation of the nucleolar mass; infiltration of lymphocytes, granulocytes and macrophages in the tumor. The significance of these ultrastructural findings is discussed. (U.S.)

  10. Human teeth with periapical pathosis after overinstrumentation and overfilling of the root canals: a scanning electron microscopic study.

    Science.gov (United States)

    Gutiérrez, J H; Brizuela, C; Villota, E

    1999-01-01

    The aim of this study was to determine whether overinstrumentation followed by immediate overfilling could be a potential risk in the treatment of infected root canals. Thirty-five human teeth with infected root canals were overinstrumented and overfilled approximately 45 min after their extraction. The experimental teeth were enlarged up to size 40 and the overinstrumentation and overfilling were checked with the aid of a magnifying glass. The specimens were fixed in glutaraldehyde plus sodium cacodylate solution and prepared for scanning electron microscope examination. Bacteria were detected on the flute of the files and mostly at the root apices around the main foramen, remaining firmly attached to resorptive lacunae despite the fact that the apices had undergone great changes, including fracture or zipping. A control group consisting of 10 human teeth root canals containing vital pulps were also overinstrumented and overfilled. No bacteria were detected on the flutes of the files, at the apices or on the extruded master cone overfilling these samples. The high percentage of bacteria adhering to the resorptive lacunae or in the flutes of files used in overinstrumented human teeth with infected root canals carry a potential risk for postoperative pain, clinical discomfort and flare-ups. The hazards observed in these circumstances do not support the one-visit treatment of teeth having acute or chronic periapical abscesses.

  11. Bald Eagle Nesting Disturbance Information 1974 Mason Neck National Wildlife Refuge

    Data.gov (United States)

    Department of the Interior — This report is a series of excerpts from various researchers discussing the impact that human disturbances have on the eagle’s ability to successfully nest, incubate...

  12. Source/sink patterns of disturbance and cross-scale mismatches in a panarchy of social-ecological landscapes

    Science.gov (United States)

    Nicola Zaccarelli; Irene Petrosillo; Giovanni Zurlini; Kurt H. Riitters

    2008-01-01

    Land-use change is one of the major factors affecting global environmental change and represents a primary human effect on natural systems. Taking into account the scales and patterns of human land uses as source/sink disturbance systems, we describe a framework to characterize and interpret the spatial patterns of disturbances along a continuum of scales in a panarchy...

  13. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  14. ROLE OF ECOLOGICAL DISTURBANCES IN EMERGENCE OF SYLVATIC ZOONOSES AND NIDAL DISEASES

    Directory of Open Access Journals (Sweden)

    Shivaji Bhattacharya

    2012-01-01

    Full Text Available Influence of human civilization and disturbance of ecology has an important role on the evolution and emergence of new sylvatic zoonoses as well as nidal diseases.Proper study of different causes and mechanisms of escape of disease agents from their natural boundaries of niche and taking of suitable biosecurity measures for those diseases should be ensured prior to any developmental and welfare activities of human which are responsible for any kind of ecological disturbance.

  15. Atomic Resolution Structures of Human Bufaviruses Determined by Cryo-Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Maria Ilyas

    2018-01-01

    Full Text Available Bufavirus strain 1 (BuV1, a member of the Protoparvovirus genus of the Parvoviridae, was first isolated from fecal samples of children with acute diarrhea in Burkina Faso. Since this initial discovery, BuVs have been isolated in several countries, including Finland, the Netherlands, and Bhutan, in pediatric patients exhibiting similar symptoms. Towards their characterization, the structures of virus-like particles of BuV1, BuV2, and BuV3, the current known genotypes, have been determined by cryo-electron microscopy and image reconstruction to 2.84, 3.79, and 3.25 Å, respectively. The BuVs, 65–73% identical in amino acid sequence, conserve the major viral protein, VP2, structure and general capsid surface features of parvoviruses. These include a core β-barrel (βB-βI, α-helix A, and large surface loops inserted between these elements in VP2. The capsid contains depressions at the icosahedral 2-fold and around the 5-fold axes, and has three separated protrusions surrounding the 3-fold axes. Structure comparison among the BuVs and to available parvovirus structures revealed capsid surface variations and capsid 3-fold protrusions that depart from the single pinwheel arrangement of the animal protoparvoviruses. These structures provide a platform to begin the molecular characterization of these potentially pathogenic viruses.

  16. Disturbance maintains alternative biome states.

    Science.gov (United States)

    Dantas, Vinícius de L; Hirota, Marina; Oliveira, Rafael S; Pausas, Juli G

    2016-01-01

    Understanding the mechanisms controlling the distribution of biomes remains a challenge. Although tropical biome distribution has traditionally been explained by climate and soil, contrasting vegetation types often occur as mosaics with sharp boundaries under very similar environmental conditions. While evidence suggests that these biomes are alternative states, empirical broad-scale support to this hypothesis is still lacking. Using community-level field data and a novel resource-niche overlap approach, we show that, for a wide range of environmental conditions, fire feedbacks maintain savannas and forests as alternative biome states in both the Neotropics and the Afrotropics. In addition, wooded grasslands and savannas occurred as alternative grassy states in the Afrotropics, depending on the relative importance of fire and herbivory feedbacks. These results are consistent with landscape scale evidence and suggest that disturbance is a general factor driving and maintaining alternative biome states and vegetation mosaics in the tropics. © 2015 John Wiley & Sons Ltd/CNRS.

  17. Tracking a major interplanetary disturbance

    International Nuclear Information System (INIS)

    Tappin, S.J.; Hewish, A.; Gapper, G.R.

    1983-01-01

    The severe geomagnetic storm which occurred during 27-29 August 1978 was remarkable because it arrived unexpectedly and was not related to a solar flare or long-lived coronal hole. Observations on 900 celestial radio sources show that the storm was associated with a large-scale region causing enhanced interplanetary scintillation which enveloped the Earth at the same time. The disturbance was first detected on 26 August, when the outer boundary had reached a distance of about 0.8 a.u. from the Sun and it was tracked until 30 August. The enhancement was followed by a fast solar wind stream and its shape suggests that it was a compression zone caused by the birth of the stream. (author)

  18. Human METTL20 methylates lysine residues adjacent to the recognition loop of the electron transfer flavoprotein in mitochondria.

    Science.gov (United States)

    Rhein, Virginie F; Carroll, Joe; He, Jiuya; Ding, Shujing; Fearnley, Ian M; Walker, John E

    2014-08-29

    In mammalian mitochondria, protein methylation is a relatively uncommon post-transcriptional modification, and the extent of the mitochondrial protein methylome, the modifying methyltransferases, and their substrates have been little studied. As shown here, the β-subunit of the electron transfer flavoprotein (ETF) is one such methylated protein. The ETF is a heterodimer of α- and β-subunits. Lysine residues 199 and 202 of mature ETFβ are almost completely trimethylated in bovine heart mitochondria, whereas ETFα is not methylated. The enzyme responsible for the modifications was identified as methyltransferase-like protein 20 (METTL20). In human 143B cells, the methylation of ETFβ is less extensive and is diminished further by suppression of METTL20. Tagged METTL20 expressed in HEK293T cells specifically associates with the ETF and promotes the trimethylation of ETFβ lysine residues 199 and 202. ETF serves as a mobile electron carrier linking dehydrogenases involved in fatty acid oxidation and one-carbon metabolism to the membrane-associated ubiquinone pool. The methylated residues in ETFβ are immediately adjacent to a protein loop that recognizes and binds to the dehydrogenases. Suppression of trimethylation of ETFβ in mouse C2C12 cells oxidizing palmitate as an energy source reduced the consumption of oxygen by the cells. These experiments suggest that the oxidation of fatty acids in mitochondria and the passage of electrons via the ETF may be controlled by modulating the protein-protein interactions between the reduced dehydrogenases and the β-subunit of the ETF by trimethylation of lysine residues. METTL20 is the first lysine methyltransferase to be found to be associated with mitochondria. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Adapted methods for scanning electron microscopy (SEM in assessment of human sperm morphology

    Directory of Open Access Journals (Sweden)

    Petra Nussdorfer

    2018-02-01

    Full Text Available Infertility is a widespread problem, and in some cases, the routine basic semen analysis is not sufficient to detect the cause of male infertility. The use of the scanning electron microscope (SEM could provide a detailed insight into spermatozoa morphology, but it requires specific sample preparation techniques. The purpose of this study was to select, adjust, and optimize a method for the preparation of spermatozoa samples prior to SEM analysis, and to establish the protocol required for its use in clinical practice. We examined sperm samples of 50 men. The samples were fixed with modified iso-osmolar aldehyde solution followed by osmium post-fixation. In the first method, dehydration of the cells and subsequent critical point drying (CPD were performed on a coverslip. In the second method, the samples were dehydrated in centrifuge tubes; hexamethyldisilazane (HMDS was used as a drying agent instead of CPD, and the samples were air-dried. The third procedure was based on a membrane filter. The samples were dehydrated and dried with HMDS in a Gooch crucible, continuously, without centrifugation or redispersion of the sample. Our results showed that the fixation with modified iso-osmolar aldehyde solution followed by osmium post-fixation, and combined with dehydration and CPD on a coverslip, is the most convenient procedure for SEM sample preparation. In the case of small-size samples or low sperm concentration, dehydration and drying with HMDS on the membrane filter enabled the best reliability, repeatability, and comparability of the results. The presented procedures are suitable for routine use, and they can be applied to confirm as well as to correct a diagnosis.

  20. Evaluation of Human Corneal Lenticule Quality After SMILE With Different Cap Thicknesses Using Scanning Electron Microscopy.

    Science.gov (United States)

    Weng, Shengbei; Liu, Manli; Yang, Xiaonan; Liu, Fang; Zhou, Yugui; Lin, Haiqin; Liu, Quan

    2018-01-01

    To evaluate the surface characteristics of lenticules created by small-incision lenticule extraction (SMILE) with different cap thicknesses. This prospective study included 20 consecutive patients who underwent bilateral SMILE. Surface regularity of the extracted corneal lenticule was analyzed using scanning electron microscopy (SEM) combined with 2 methods: qualitative and quantitative regularity. Qualitative regularity of SEM images was graded by masked observers using an established scoring system. Quantitative regularity of SEM images was assessed by counting the total number and areas of tissue bridges using Image-Pro Plus software. Four different cap thickness of 120, 130, 140, and 150 μm were compared. Refractive outcomes of patients were measured at baseline and 1 month after surgery. As 10 specimens were not analyzable, only 30 eyes were included. Postoperatively, all eyes had postoperative uncorrected distance visual acuity of 20/20 or better; 43% had an unchanged corrected distance visual acuity; 43% gained 1 line; 10% lost 1 line. Ultrastructurally, surface irregularity was primarily caused by tissue bridges. The average surface regularity score obtained was 10.87 ± 2.40 for 120 μm, 10.78 ± 2.60 for 130 μm, 8.76 ± 2.16 for 140 μm, and 8.70 ± 2.66 for 150 μm (P < 0.001). The total number and areas of tissue bridges of 120 to 130 μm were significantly less than 140 to 150 μm (P < 0.05). Surface regularity decreased as cap thickness increased (P < 0.05). There is smoother appearance of the lenticular surface as seen through SEM when a thin cap is created compared with a thick cap qualitatively and quantitatively.

  1. Increased sensitivity to climate change in disturbed ecosystems

    DEFF Research Database (Denmark)

    Kroël-Dulay, György; Ransijn, Johannes; Schmidt, Inger Kappel

    2015-01-01

    Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports this relatio......Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports...... this relationship for the perturbation of climate change. Here we show that vegetation (abundance, species richness and species composition) across seven European shrublands is quite resistant to moderate experimental warming and drought, and responsiveness is associated with the dynamic state of the ecosystem...

  2. Effects of climate change on ecological disturbance in the Northern Rockies Region [Chapter 8

    Science.gov (United States)

    Loehman, Rachel A.; Bentz, Barbara J.; DeNitto, Gregg A.; Keane, Robert E.; Manning, Mary E.; Duncan, Jacob P.; Egan, Joel M.; Jackson, Marcus B.; Kegley, Sandra; Lockman, I. Blakey; Pearson, Dean E.; Powell, James A.; Shelly, Steve; Steed, Brytten E.; Zambino, Paul J.

    2018-01-01

    This chapter describes the ecology of important disturbance regimes in the Forest Service, U.S. Department of Agriculture (USFS) Northern Region and the Greater Yellowstone Area, hereafter called the Northern Rockies region, and potential shifts in these regimes as a consequence of observed and projected climate change. The term disturbance regime describes the general temporal and spatial characteristics of a disturbance agent - insect, disease, fire, weather, even human activity - and the effects of that agent on the landscape (table 8.1). More specifically, a disturbance regime is the cumulative effect of multiple disturbance events over space and time (Keane 2013). Disturbances disrupt an ecosystem, community, or population structure and change elements of the biological environment, physical environment, or both (White and Pickett 1985). The resulting shifting mosaic of diverse ecological patterns and structures in turn affects future patterns of disturbance, in a reciprocal, linked relationship that shapes the fundamental character of landscapes and ecosystems. Disturbance creates and maintains biological diversity in the form of shifting, heterogeneous mosaics of diverse communities and habitats across a landscape (McKinney and Drake 1998), and biodiversity is generally highest when disturbance is neither too rare nor too frequent on the landscape (Grime 1973).

  3. Radiosensitivity of different aged human lymphocytes following electron irradiation in vitro

    International Nuclear Information System (INIS)

    Joksic, G.; Nikolic, M.; Spasojevic-Tisma, V.

    1997-01-01

    Cytochalasin B-blocking micronucleus test and chromosomal aberration analysis were used in this study to estimate the yield of individual variability in radiation response of different aged human lymphocytes. Both analyses were performed in three groups of adults, aged 18-65 years, on two sampling times, following irradiation by therapeutical dose of 2 G in vitro. No statistically significant difference in the induced yield of exchange aberrations between individuals under consideration was found. The yield of total aberration data showed greater variability and was statistically significant in the oldest group against two other adult groups. Regarding to fixation times no statistically significant differences in the induced yield of chromosomal aberration (exchanges as well as total aberrations) were observed. The study has shown a slight increase in spontaneously occurring micronuclei with age. Almost equal mean number of radiation induced micronuclei was observed in the groups of adult aged 18-20 and 45-55 years. The highest mean number was observed in the oldest group. Evident variation in number of radiation induced micronuclei among individuals from the same age group was observed. The results of micronuclei assay for for all individuals under consideration show statistically significant difference in the yield of radiation-induced micronuclei regarding the second fixation time. This study has shown that cytochalasin-B blocking micronucleus test is more sensitive assay than chromosomal aberration analysis for the estimation of individual radiosensitivity. (author)

  4. Color 3D electronic imaging of the surface of the human body

    Science.gov (United States)

    Rioux, Marc

    1994-10-01

    The NRC laboratories have developed a laser scanning technique to digitize shapes and colors in registration. The technique, known as synchronized scanning, is capable of digitizing topography as small as the relief of a bare finger tip, showing a clear picture of the skin structure (essentially a clean fingerprint without distortion), as well as the shape and size of body components such as hands, face, and feet, and the full body of one or more subjects simultaneously. The laser scanner uses a RGB laser, coupled to an optical fiber, which is projected in the field of view. The 3D color measurements are made by optical triangulation to a resolution of 10 micrometers for finger tip scans and a resolution of 1 mm for whole body scans. Experimental results are presented and discussed. Potential applications of this technology in the field of identification and inspection of humans include face recognition, finger, foot and teeth print identification, and 3D mugshots that can be rapidly broadcast through satellite communication. One of the unique properties of this technology is that absolute measurements, not only appearance and relative position of features, can be used for identification purposes.

  5. Soil disturbance as a grassland restoration measure

    DEFF Research Database (Denmark)

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success...... to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration...

  6. Electron microscopic study of the myelinated nerve fibres and the perineurial cell basement membrane in the diabetic human peripheral nerves

    International Nuclear Information System (INIS)

    ElBarrany, Wagih G.; Hamdy, Raid M.; AlHayani, Abdulmonem A.; Jalalah, Sawsan M.

    2009-01-01

    To study the quantitative and ultrastructural changes in myelinated nerve fibers and the basement membranes of the perineurial cells in diabetic nerves. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Saudi Arabia from 2003 to 2005. Human sural nerves were obtained from 15 lower limbs and 5 diabetic nerve biopsies. The total mean and density of myelinated nerve fibers per fascicle were calculated, with density of microtubules and mitochondria in the axoplasm. The number of the perineurial cell basement membrane layers was counted, and thickness of the basement membrane was measured. Among the 15 diabetic and 5 normal human sural nerves, the average diameters, number and surface area of myelinated nerve fibers and axonal microtubules density were found to be less in diabetic nerves. Mitochondrial density was higher in diabetic axons. Thickness of the perineurial cell basement membrane had a greater mean, but the number of perineurial cell layers was less than that of the diabetic group. The inner cellular layer of the perineurium of the diabetic nerves contained large vacuoles containing electron-dense degenerated myelin. A few specimens showed degenerated myelinated nerve fibers, while others showed recovering ones. Retracted axoplasms were encountered with albumin extravasation. Diabetes caused an increase in perineurial permeability. The diabetic sural nerve showed marked decrease in the myelinated nerve fibres, increase degenerated mitochondria, and decreased microtubules. (author)

  7. The use of intermediate electron acceptors to enhance MTT bioreduction in a microculture tetrazolium assay for human growth hormone.

    Science.gov (United States)

    Goodwin, C J; Holt, S J; Downes, S; Marshall, N J

    1996-01-01

    We contrast the effects of three intermediate electron acceptors (IEAs) on the highly quantitative ESTA bioassay for human growth hormone. This is a microculture tetrazolium assay based upon the in vitro reduction of the tetrazolium salt MTT, by Nb2 cells which have been activated with hGH. Each of the IEAs influenced MTT-formazan production in a distinctive manner. The two quinonoids, namely menadione and co-enzyme Q0 markedly increased the MTT-formazan produced by hormone activated Nb2 cells and thereby amplified the response of our bioassay for human growth hormone (hGH). The exceptionally low bioassay baseline which is characteristic of the unstimulated Nb2 cells when only MTT is added was retained in the presence of CoQ0, but was greatly increased by menadione. Phenazine methosulphate, which is the most widely used redox intermediary in microculture tetrazolium assays, also increased the baseline, but had only a minimal additional effect on MTT reduction by activated Nb2 cells. We conclude that CoQ0 is the preferred IEA for this ESTA bioassay for hGH.

  8. Comparison of the external physical damages between laser-assisted and mechanical immobilized human sperm using scanning electronic microscopy.

    Directory of Open Access Journals (Sweden)

    David Y L Chan

    Full Text Available We aim to visualize the external physical damages and distinct external phenotypic effects between mechanical and laser-assisted immobilized human spermatozoa using scanning electronic microscopy (SEM. Human spermatozoa were immobilized mechanically or with laser assistance for SEM examination and the membrane integrities were checked on both types of immobilized spermatozoa. We found evidence of external damages at SEM level on mechanically kinked sperm, but not on laser-assisted immobilized sperm. Although no external damage was found on laser-assist immobilized sperm, there were two distinct types of morphological changes when spermatozoa were stricken by infra-red laser. Coiled tails were immediately formed when Laser pulse was applied to the sperm end piece area, whereas laser applied to the sperm principal piece area resulted in a sharp bend of sperm tails. Sperm immobilized by laser did not exhibit any morphological change if the laser did not hit within the on-screen central target zone or if the laser hit the sperm mid piece or head. Our modified membrane integrity assay revealed that the external membrane of more than half of the laser-assisted immobilized sperm remained intact. In conclusion, mechanical immobilization produced membrane damages whilst laser-assisted immobilization did not result in any external membrane damages besides morphological changes at SEM level.

  9. The Application of Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM-EDX) in Ancient Dental Calculus for the Reconstruction of Human Habits

    Czech Academy of Sciences Publication Activity Database

    Fialová, D.; Skoupý, Radim; Drozdová, E.; Paták, Aleš; Piňos, Jakub; Šín, L.; Beňuš, R.; Klíma, B.

    2017-01-01

    Roč. 23, č. 6 (2017), s. 1207-1213 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : ancient dental calculus * SEM-EDX * human habits * the Great Moravian Empire * Napoleonic Wars Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering Impact factor: 1.891, year: 2016

  10. Numerical modelling of the structure of electromagnetic disturbances generated by acoustic-gravity waves

    International Nuclear Information System (INIS)

    Pogorel'tsev, A.I.; Bidlingmajer, E.R.

    1992-01-01

    A numeric model of electromagnetic field disturbances generated under the interaction of acoustic-gravitational waves with ionospheric plasma is elaborated and vertical structure of the above disturbances is calculated. The estimates shown that electromagnetic disturbances can penetrate into neutral atmosphere and can be recorded through measurements of the variation of magnetic field and electron field vertical component near the earth is surface. A conclusion is made on a feasibility of monitoring of acoustic-gravitational wave activity in the lower thermosphere through land measurements of magnetic and electric field variations

  11. Inverting Coseismic TEC Disturbances for Neutral Atmosphere Pressure Wave

    Science.gov (United States)

    Lee, R. F.; Mikesell, D.; Rolland, L.

    2017-12-01

    Research from the past 20 years has shown that we can detect coseismic disturbances in the total electron content (TEC) using global navigation space systems (GNSS). In the near field, TEC disturbances are created by the direct wave from rupture on the surface. This pressure wave travels through the neutral atmosphere to the ionosphere within about 10 minutes. This provides the opportunity to almost immediately characterize the source of the acoustic disturbance on the surface using methods from seismology. In populated areas, this could provide valuable information to first responders. To retrieve the surface motion amplitude information we must account for changes in the waveform caused by the geomagnetic field, motion of the satellites and the geometry of the satellites and receivers. One method is to use a transfer function to invert for the neutral atmosphere pressure wave. Gómez et al (2015) first employed an analytical model to invert for acoustic waves produced by Rayleigh waves propagating along the Earth's surface. Here, we examine the same model in the near field using the TEC disturbances from the direct wave produced by rupture at the surface. We compare results from the forward model against a numerical model that has been shown to be in good agreement with observations from the 2011 Van (Turkey) earthquake. We show the forward model predictions using both methods for the Van earthquake. We then analyze results for hypothetical events at different latitudes and discuss the reliability of the analytical model in each scenario. Gómez, D., R. Jr. Smalley, C. A. Langston, T. J. Wilson, M. Bevis, I. W. D. Dalziel, E. C. Kendrick, S. A. Konfal, M. J. Willis, D. A. Piñón, et al. (2015), Virtual array beamforming of GPS TEC observations of coseismic ionospheric disturbances near the Geomagnetic South Pole triggered by teleseismic megathrusts, J. Geophys. Res. Space Physics, 120, 9087-9101, doi:10.1002/2015JA021725.

  12. The role of forest disturbance in global forest mortality and terrestrial carbon fluxes

    Science.gov (United States)

    Pugh, Thomas; Arneth, Almut; Smith, Benjamin; Poulter, Benjamin

    2017-04-01

    Large-scale forest disturbance dynamics such as insect outbreaks, wind-throw and fires, along with anthropogenic disturbances such as logging, have been shown to turn forests from carbon sinks into intermittent sources, often quite dramatically so. There is also increasing evidence that disturbance regimes in many regions are changing as a result of climatic change and human land-management practices. But how these landscape-scale events fit into the wider picture of global tree mortality is not well understood. Do such events dominate global carbon turnover, or are their effects highly regional? How sensitive is global terrestrial carbon exchange to realistic changes in the occurrence rate of such disturbances? Here, we combine recent advances in global satellite observations of stand-replacing forest disturbances and in compilations of forest inventory data, with a global terrestrial ecosystem model which incorporates an explicit representation of the role of disturbance in forest dynamics. We find that stand-replacing disturbances account for a fraction of wood carbon turnover that varies spatially from less than 5% in the tropical rainforest to ca. 50% in the mid latitudes, and as much as 90% in some heavily-managed regions. We contrast the size of the land-atmosphere carbon flux due to this disturbance with other components of the terrestrial carbon budget. In terms of sensitivity, we find a quasi log-linear relationship of disturbance rate to total carbon storage. Relatively small changes in disturbance rates at all latitudes have marked effects on vegetation carbon storage, with potentially very substantial implications for the global terrestrial carbon sink. Our results suggest a surprisingly small effect of disturbance type on large-scale forest vegetation dynamics and carbon storage, with limited evidence of widespread increases in nitrogen limitation as a result of increasing future disturbance. However, the influence of disturbance type on soil carbon

  13. Isolated ionospheric disturbances as deduced from global GPS network

    Directory of Open Access Journals (Sweden)

    E. L. Afraimovich

    2004-01-01

    Full Text Available We investigate an unusual class of medium-scale traveling ionospheric disturbances of the nonwave type, isolated ionospheric disturbances (IIDs that manifest themselves in total electron content (TEC variations in the form of single aperiodic negative TEC disturbances of a duration of about 10min (the total electron content spikes, TECS. The data were obtained using the technology of global detection of ionospheric disturbances using measurements of TEC variations from a global network of receivers of the GPS. For the first time, we present the TECS morphology for 170 days in 1998–2001. The total number of TEC series, with a duration of each series of about 2.3h (2h18m, exceeded 850000. It was found that TECS are observed in no more than 1–2% of the total number of TEC series mainly in the nighttime in the spring and autumn periods. The TECS amplitude exceeds the mean value of the "background" TEC variation amplitude by a factor of 5–10 as a minimum. TECS represent a local phenomenon with a typical radius of spatial correlation not larger than 500km. The IID-induced TEC variations are similar in their amplitude, form and duration to the TEC response to shock-acoustic waves (SAW generated during rocket launchings and earthquakes. However, the IID propagation velocity is less than the SAW velocity (800–1000m/s and are most likely to correspond to the velocity of background medium-scale acoustic-gravity waves, on the order of 100–200m/s. Key words. Ionosphere (ionospheric irregularities, instruments and techniques - Radio science (ionospheric propagation

  14. Variability in fluvial geomorphic response to anthropogenic disturbance

    Science.gov (United States)

    Verstraeten, Gert; Broothaerts, Nils; Van Loo, Maarten; Notebaert, Bastiaan; D'Haen, Koen; Dusar, Bert; De Brue, Hanne

    2017-10-01

    Humans have greatly impacted the processes and intensities of erosion, sediment transport and storage since the introduction of agriculture. In many regions around the world, accelerated floodplain sedimentation can be related to increases in human pressure on the environment. However, the relation between the intensity of anthropogenic disturbance and the magnitude of change in fluvial sediment dynamics is not straightforward and often non-linear. Here, we review a number of case studies from contrasting environmental settings in the European loess belt, the Eastern Mediterranean mountain ranges and the eastern USA. Detailed field-based sediment archive studies and sediment budgets covering time periods ranging from 200 to over 5000 year, as well as the use of pollen and sediment provenance techniques, show that no overarching concept of changes in floodplain sedimentation following anthropogenic disturbance can be established. Slope-channel (dis)connectivity controls the existence of thresholds or tipping points that need to be crossed before significant changes in downstream sediment dynamics are recorded following human impact. This coupling can be related to characteristics of human pressure such as its duration, intensity and spatial patterns, but also to the geomorphic and tectonic setting. Furthermore, internal feedback mechanisms, such as those between erosion and soil thickness, further complicate the story. All these factors controlling the propagation of sediment from eroding hillslopes to river channels vary between regions. Hence, only unique patterns of fluvial geomorphic response can be identified. As a result, unravelling the human impact from current-day sediment archives and predicting the impact of future human disturbances on fluvial sediment dynamics remain a major challenge. This has important implications for interpreting contemporary sediment yields as well as downstream sediment records in large floodplains, deltas and the marine

  15. Highways Disturbance Detection with the Use of Open Source Code Geographic Information Systems, Mobile and Web Applications

    Science.gov (United States)

    Sabah, L.; Şimşek, M.

    2017-11-01

    Road disturbances are occurring in our country due to the highway-weighted transportation. These disturbances are caused by human and natural causes. Disturbances in the roads have a negative effect on human life as well as damage to the vehicles. Regardless of how it occurs, it is important to quickly detect and eliminate roadside disturbances. The use of mobile devices has become widespread with developing technologies. Today, many sensors such as GPS and accelerometer are used to detect road disturbances on mobile devices. In this context, it is important to use mobile applications for fast and in-situ detection. In this study, it is investigated the use of mobile devices' location data received from GPS sensors with special mobile interfaces in gathering road data for road disturbances.

  16. Harmonic disturbance location by applying Bayesian inference

    NARCIS (Netherlands)

    Ye, G.; Xiang, Y.; Cuk, V.; Cobben, J.F.G.

    2016-01-01

    Harmonic pollution is one of the most important power quality issues in electric power systems. Correct location of the main harmonic disturbance source is a key step to solve the problem. This paper presents a method to detect the location of harmonic disturbance source in low voltage network

  17. A Full Disturbance Model for Reaction Wheels

    NARCIS (Netherlands)

    Le, M.P.; Ellenbroek, Marcellinus Hermannus Maria; Seiler, R; van Put, P.; Cottaar, E.J.E.

    2014-01-01

    Reaction wheels are rotating devices used for the attitude control of spacecraft. However, reaction wheels also generate undesired disturbances in the form of vibrations, which may have an adverse effect on the pointing accuracy and stability of spacecraft (optical) payloads. A disturbance model for

  18. Nonunity gain minimal-disturbance measurement

    DEFF Research Database (Denmark)

    Sabuncu, Metin; Mišta, L.; Fiurášek, J.

    2007-01-01

    We propose and experimentally demonstrate an optimal nonunity gain Gaussian scheme for partial measurement of an unknown coherent state that causes minimal disturbance of the state. The information gain and the state disturbance are quantified by the noise added to the measurement outcomes...

  19. The Dimensionality of Body Image Disturbance.

    Science.gov (United States)

    Galgan, Richard J.; And Others

    1987-01-01

    Examined personality variables in 75 male and 75 female college students. Found two dimensions underlying body image disturbance variables, one loading on body image dissatisfaction and one loading on body image disturbance. Low negative correlation between two factors suggests that distortion and dissatisfaction are fairly distinct and that body…

  20. Instrumentation for Power System Disturbance Monitoring, Data ...

    African Journals Online (AJOL)

    In this paper, the level of instrumentation for power system disturbance monitoring, data acquisition and control in Nigerian Electric Power System; National Electric Power Authority (NEPA) is presented. The need for accurate power system disturbance monitoring is highlighted. A feature of an adequate monitoring, data ...

  1. Transience after disturbance: Obligate species recovery dynamics depend on disturbance duration.

    Science.gov (United States)

    Singer, Alexander; Johst, Karin

    2017-06-01

    After a disturbance event, population recovery becomes an important species response that drives ecosystem dynamics. Yet, it is unclear how interspecific interactions impact species recovery from a disturbance and which role the disturbance duration (pulse or press) plays. Here, we analytically derive conditions that govern the transient recovery dynamics from disturbance of a host and its obligately dependent partner in a two-species metapopulation model. We find that, after disturbance, species recovery dynamics depend on the species' role (i.e. host or obligately dependent species) as well as the duration of disturbance. Host recovery starts immediately after the disturbance. In contrast, for obligate species, recovery depends on disturbance duration. After press disturbance, which allows dynamics to equilibrate during disturbance, obligate species immediately start to recover. Yet, after pulse disturbance, obligate species continue declining although their hosts have already begun to increase. Effectively, obligate species recovery is delayed until a necessary host threshold occupancy is reached. Obligates' delayed recovery arises solely from interspecific interactions independent of dispersal limitations, which contests previous explanations. Delayed recovery exerts a two-fold negative effect, because populations continue declining to even smaller population sizes and the phase of increased risk from demographic stochastic extinction in small populations is prolonged. We argue that delayed recovery and its determinants -species interactions and disturbance duration - have to be considered in biodiversity management. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Disturbing, Disordered or Disturbed? Perspectives on the Definition of Problem Behavior in Educational Settings.

    Science.gov (United States)

    Wood, Frank H., Ed.; Lakin, K. Charlie, Ed.

    The book contains five papers presented at a 1979 topical conference on the definition of emotional disturbance and behavioral disorders in educational settings. The first paper, by F. Wood, is titled "Defining Disturbing, Disordered, and Disturbed Behavior." Topics covered include ambivalence about defining deviant behavior by special educators,…

  3. Discovering Coseismic Traveling Ionospheric Disturbances Generated by the 2016 Kaikoura Earthquake

    Science.gov (United States)

    Li, J. D.; Rude, C. M.; Gowanlock, M.; Pankratius, V.

    2017-12-01

    Geophysical events and hazards, such as earthquakes, tsunamis, and volcanoes, have been shown to generate traveling ionospheric disturbances (TIDs). These disturbances can be measured by means of Total Electron Content fluctuations obtained from a network of multifrequency GPS receivers in the MIT Haystack Observatory Madrigal database. Analyzing the response of the ionosphere to such hazards enhances our understanding of natural phenomena and augments our large-scale monitoring capabilities in conjunction with other ground-based sensors. However, it is currently challenging for human investigators to spot and characterize such signatures, or whether a geophysical event has actually occurred, because the ionosphere can be noisy with multiple simultaneous phenomena taking place at the same time. This work therefore explores a systematic pipeline for the ex-post discovery and characterization of TIDs. Our technique starts by geolocating the event and gathering the corresponding data, then checks for potentially conflicting TID sources, and processes the raw total electron content data to generate differential measurements. A Kolmogorov-Smirnov test is applied to evaluate the statistical significance of detected deviations in the differential measurements. We present results from our successful application of this pipeline to the 2016 7.8 Mw Kaikoura earthquake occurring in New Zealand on November 13th. We detect a coseismic TID occurring 8 minutes after the earthquake and propagating towards the equator at 1050 m/s, with a 0.22 peak-to-peak TECu amplitude. Furthermore, the observed waveform exhibits more complex behavior than the expected N-wave for a coseismic TID, which potentially results from the complex multi-fault structure of the earthquake. We acknowledge support from NSF ACI1442997 (PI Pankratius), NASA AISTNNX15AG84G (PI Pankratius), and NSF AGS-1343967 (PI Pankratius), and NSF AGS-1242204 (PI Erickson).

  4. Human- Versus System-Level Factors and Their Effect on Electronic Work List Variation: Challenging Radiology's Fundamental Attribution Error.

    Science.gov (United States)

    Davenport, Matthew S; Khalatbari, Shokoufeh; Platt, Joel F

    2015-09-01

    The aim of this study was to analyze sources of variation influencing the unread volume on an electronic abdominopelvic CT work list and to compare those results with blinded radiologist perception. The requirement for institutional review board approval was waived for this HIPAA-compliant quality improvement effort. Data pertaining to an electronic abdominopelvic CT work list were analyzed retrospectively from July 1, 2013, to June 30, 2014, and modeled with respect to the unread case total at 6 pm (Monday through Friday, excluding holidays). Eighteen system-level factors outside individual control (eg, number of workers, workload) and 7 human-level factors within individual control (eg, individual productivity) were studied. Attending radiologist perception was assessed with a blinded anonymous survey (n = 12 of 15 surveys completed). The mean daily unread total was 24 (range, 3-72). The upper control limit (48 CT studies [3 SDs above the mean]) was exceeded 10 times. Multivariate analysis revealed that the rate of unread CT studies was affected principally by system-level factors, including the number of experienced trainees on service (postgraduate year 5 residents [odds ratio, 0.83; 95% confidence interval, 0.74-0.92; P = .0008] and fellows [odds ratio, 0.84; 95% confidence interval, 0.74-0.95; P = .005]) and the daily workload (P = .02 to P level factors best predict the variation in unread CT examinations, but blinded faculty radiologists believe that it relates most strongly to variable individual effort. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  5. Disturbance analysis in nuclear power plants

    International Nuclear Information System (INIS)

    Sillamaa, M.A.

    Disturbance analysis is any systematic procedure that helps an operator determine what has failed. This paper describes the typical information currently provided in CANDU power plants to help the operator respond to a disturbance. It presents a simplified model of how an operator could get into trouble, and briefly reviews development work on computerized disturbance analysis systems for nuclear power plants being done in various countries including Canada. Disturbance analysis systems promise to be useful tools in helping operators improve their response to complex situations. However, the originality and complexity of the work for a disturbance analysis system and the need to develop operator confidence and management support require a 'walk before you run' approach

  6. Recovery of lotic macroinvertebrate communities from disturbance

    Science.gov (United States)

    Wallace, J. Bruce

    1990-09-01

    Ecosystem disturbances produce changes in macrobenthic community structure (abundances, biomass, and production) that persist for a few weeks to many decades. Examples of disturbances with extremely long-term effects on benthic communities include contamination by persistent toxic agents, physical changes in habitats, and altered energy inputs. Stream size, retention, and local geomorphology may ameliorate the influence of disturbances on invertebrates. Disturbances can alter food webs and may select for favorable genotypes (e.g., insecticidal resistance). Introductions of pesticides into lotic ecosystems, which do not result in major physical changes within habitats, illustrate several factors that influence invertebrate recovery time from disturbance. These include: (1) magnitude of original contamination, toxicity, and extent of continued use; (2) spatial scale of the disturbance; (3) persistence of the pesticide; (4) timing of the contamination in relation to the life history stages of the organisms; (5) vagility of populations influenced by pesticides; and (6) position within the drainage network. The ability of macroinvertebrates to recolonize denuded stream habitats may vary greatly depending on regional life histories, dispersal abilities, and position within the stream network (e.g., headwaters vs larger rivers). Although downstream drift is the most frequently cited mechanism of invertebrate recolonization following disturbance in middle- and larger-order streams, evidence is presented that shows aerial recolonization to be potentially important in headwater streams. There is an apparent stochastic element operating for aerial recolonization, depending on the timing of disturbance and flight periods of various taxa. Available evidence indicates that recolonization of invertebrate taxa without an aerial adult stage requires longer periods of time than for those that possess winged, terrestrial adult stages (i.e., most insects). Innovative, manipulative

  7. Acute Exposure to Electronic and Combustible Cigarette Aerosols: Effects in an Animal Model and in Human Alveolar Cells.

    Science.gov (United States)

    Husari, Ahmad; Shihadeh, Alan; Talih, Soha; Hashem, Yasmine; El Sabban, Marwan; Zaatari, Ghazi

    2016-05-01

    Smoking electronic cigarettes (ECIG) is promoted as a safer alternative to smoking combustible cigarettes. This study investigates the effects of ECIG aerosol and cigarette smoke (CS) in an animal model and in human alveolar cell cultures (A549). Mice were divided into Control, ECIG, and CS. Animals were exposed for 6h/d to either lab air, ECIG or CS, for of 3 days. Total particulate matter exposure for the ECIG was set at higher levels compared to CS. Lung injury was determined by: (1) measurement of wet-to-dry ratio; (2) albumin concentration in the bronchoalveolar lavage fluid; (3) transcriptional expression of inflammatory mediators IL-1β, IL-6, TNF-α; (4) oxidative stress; (5) assessment of cell death; and (6) lung histopathology. Human alveolar cell cultures were treated with various concentrations of ECIG and CS aerosol extracts and the effects on cell proliferation were evaluated. Wet-to-dry ratio was higher in CS when compared to ECIG. Albumin leak in bronchoalveolar lavage fluid was evident in CS but not in ECIG. ECIG exposure was only associated with a significant increase in IL-1β. In contrast, CS exposure resulted in significant increases in IL-1β, IL-6, TNF-α expression, and oxidative stress. TUNEL staining demonstrated significant cell death in CS but not in ECIG. At the cellular level, ECIG and CS extracts reduced cell proliferation, however, CS exhibited effects at lower concentrations. Despite higher exposure conditions, ECIG exhibited less toxic effects on lungs of experimental animals and on A549 cell cultures when compared to CS. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Mitochondrial electron transport is inhibited by disappearance of metallothionein in human bronchial epithelial cells following exposure to silver nitrate.

    Science.gov (United States)

    Miyayama, Takamitsu; Arai, Yuta; Suzuki, Noriyuki; Hirano, Seishiro

    2013-03-08

    Silver (Ag) possesses antibacterial activity and has been used in wound dressings and deodorant powders worldwide. However, the metabolic behavior and biological roles of Ag in mammals have not been well characterized. In the present study, we exposed human bronchial epithelial cells (BEAS-2B) to AgNO3 and investigated uptake and intracellular distribution of Ag, expression of metallothionein (MT), generation of reactive oxygen species (ROS), and changes in mitochondrial respiration. The culture medium concentration of Ag decreased with time and stabilized at 12h. The concentration of both Ag and MT in the soluble cellular fraction increased up to 3h and then decreased, indicating that cytosolic Ag relocated to the insoluble fraction of the cells. The levels of mRNAs for the major human MT isoforms MT-I and MT-II paralleled with the protein levels of Ag-MT. The intensity of fluorescence derived from ROS was elevated in the mitochondrial region at 24h. Ag decreased mitochondrial oxygen consumption in a dose-dependent manner and the activity of mitochondrial complex I-IV enzymes was significantly inhibited following exposure to Ag. In a separate experiment, we found that hydrogen peroxide (H2O2) at concentrations as low as 0.001% (equivalent to the concentration of H2O2 in Ag-exposed cells) removed Ag from MT. These results suggest MT was decomposed by cytosolic H2O2, and then Ag released from MT relocated to insoluble cellular fractions and inhibited electron chain transfer of mitochondrial complexes, which eventually led to cell damage. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  9. Levels and risk factors of antimony contamination in human hair from an electronic waste recycling area, Guiyu, China.

    Science.gov (United States)

    Huang, Yue; Ni, Wenqing; Chen, Yaowen; Wang, Xiaoling; Zhang, Jingwen; Wu, Kusheng

    2015-05-01

    The primitive electronic waste (e-waste) recycling has brought a series of environmental pollutants in Guiyu, China. Antimony is one of the important metal contaminants and has aroused the global concerns recently. We aimed to investigate concentrations of antimony in human hair from Guiyu and compared them with those from a control area where no e-waste recycling exists, and assessed the potential risk factors. A total of 205 human hair samples from Guiyu and 80 samples from Jinping were collected for analysis. All volunteers were asked to complete a questionnaire including socio-demographic characteristics and other possible factors related to hair antimony exposure. The concentrations of hair antimony were analyzed using atomic absorption spectrophotometer. Our results indicated that the level of hair antimony in volunteers from Guiyu (median, 160.78; range, 6.99-4412.59 ng/g) was significantly higher than those from Jinping (median, 61.74; range, 2.98-628.43 ng/g). The residents who engaged in e-waste recycling activities in Guiyu had higher hair antimony concentrations than others (P recycling. Multiple stepwise regression analysis indicated that hair antimony concentrations were associated with education level (β = -0.064), the time of residence in Guiyu (β = 0.112), living house also served as e-waste workshop (β = 0.099), the work related to e-waste (β = 0.169), and smoking (β = 0.018). The elevated hair antimony concentrations implied that the residents in Guiyu might be at high risk of antimony contamination, especially the e-waste recycling workers. Work related to e-waste recycling activities and long-time residence in Guiyu contributed to the high hair antimony exposure.

  10. Extinction Risk in Successional Landscapes Subject to Catastrophic Disturbances

    Directory of Open Access Journals (Sweden)

    David Boughton

    2002-12-01

    Full Text Available We explore the thesis that stochasticity in successional-disturbance systems can be an agent of species extinction. The analysis uses a simple model of patch dynamics for seral stages in an idealized landscape; each seral stage is assumed to support a specialist biota. The landscape as a whole is characterized by a mean patch birth rate, mean patch size, and mean lifetime for each patch type. Stochasticity takes three forms: (1 patch stochasticity is randomness in the birth times and sizes of individual patches, (2 landscape stochasticity is variation in the annual means of birth rate and size, and (3 turnover mode is whether a patch is eliminated by disturbance or by successional change. Analytical and numerical analyses of the model suggest that landscape stochasticity is the most important agent. Landscape stochasticity increases the extinction risk to species by increasing the risk that the habitat will fluctuate to zero, by reducing the mean abundance of species, and by increasing the variance in species abundance. The highest risk was found to occur in species that inhabit patches with short lifetimes. The results of this general model suggest an important mechanism by which climate change threatens biodiversity: an increase in the frequency of extreme climate events will probably cause pulses of disturbance during some time periods; these in turn would cause wider fluctuations in annual disturbance rates and thus increase the overall level of landscape stochasticity. However, the model also suggests that humans can manipulate landscape stochasticity to reduce risk. In particular, if managed disturbances were more evenly distributed in time, attrition of the regional biota might be prevented. Other work on the connection between patch dynamics and extinction risk assumes the absence of landscape stochasticity and thus overlooks an important component of risk to biodiversity.

  11. An Adaptive Orientation Estimation Method for Magnetic and Inertial Sensors in the Presence of Magnetic Disturbances

    Directory of Open Access Journals (Sweden)

    Bingfei Fan

    2017-05-01

    Full Text Available Magnetic and inertial sensors have been widely used to estimate the orientation of human segments due to their low cost, compact size and light weight. However, the accuracy of the estimated orientation is easily affected by external factors, especially when the sensor is used in an environment with magnetic disturbances. In this paper, we propose an adaptive method to improve the accuracy of orientation estimations in the presence of magnetic disturbances. The method is based on existing gradient descent algorithms, and it is performed prior to sensor fusion algorithms. The proposed method includes stationary state detection and magnetic disturbance severity determination. The stationary state detection makes this method immune to magnetic disturbances in stationary state, while the magnetic disturbance severity determination helps to determine the credibility of magnetometer data under dynamic conditions, so as to mitigate the negative effect of the magnetic disturbances. The proposed method was validated through experiments performed on a customized three-axis instrumented gimbal with known orientations. The error of the proposed method and the original gradient descent algorithms were calculated and compared. Experimental results demonstrate that in stationary state, the proposed method is completely immune to magnetic disturbances, and in dynamic conditions, the error caused by magnetic disturbance is reduced by 51.2% compared with original MIMU gradient descent algorithm.

  12. Assignment of electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) to human chromosome 4q33 by fluorescence in situ hybridization and somatic cell hybridization.

    Science.gov (United States)

    Spector, E B; Seltzer, W K; Goodman, S I

    1999-08-01

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a nuclear-encoded protein located in the inner mitochondrial membrane. Inherited defects of ETF-QO cause glutaric acidemia type II. We here describe the localization of the ETF-QO gene to human chromosome 4q33 by somatic cell hybridization and fluorescence in situ hybridization. Copyright 1999 Academic Press.

  13. Antioxidant capacity of hesperidin from citrus peel using electron spin resonance and cytotoxic activity against human carcinoma cell lines.

    Science.gov (United States)

    Al-Ashaal, Hanan A; El-Sheltawy, Shakinaz T

    2011-03-01

    Hesperidin is a flavonoid that has various pharmacological activities including anti-inflammatory, antimicrobial and antiviral activities. The aim of the study is the isolation of hesperidin from the peel of Citrus sinensis L. (Rutaceae), and the evaluation of its antioxidant capacity and cytotoxicity against different human carcinoma cell lines. In the present work, hesperidin is identified and confirmed using chromatographic and spectral analysis. To correlate between hesperidin concentration and antioxidant capacity of peel extracts, extraction was carried out using 1% HCl-MeOH, MeOH, alkaline solution, the concentration of hesperidin determined qualitatively and quantitatively using high performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC) analysis, in vitro antioxidant capacity of hesperidin and the extracts against free radical diphenylpicrylhydrazyl (DPPH•) performed using an electron spin resonance spectrophotometer (ESR). Cytotoxic assay against larynx, cervix, breast and liver carcinoma cell lines was performed. Hesperidin was found to be moderately active as an antioxidant agent; its capacity reached 36%. In addition, the results revealed that hesperidin exhibited pronounced anticancer activity against the selected cell lines. IC₅₀ were 1.67, 3.33, 4.17, 4.58 µg/mL, respectively. Orange peels are considered to be a cheap source for hesperidin which may be used in the pharmaceutical industry as a natural chemopreventive agent. Hesperidin and orange peel extract could possess antioxidant properties with a wide range of therapeutic applications.

  14. An investigation on motor-driven power steering-based crosswind disturbance compensation for the reduction of driver steering effort

    Science.gov (United States)

    Kim, Kyuwon; Kim, Boemjun; Go, Youngil; Park, Jaeyong; Park, Joonhong; Suh, Insoo; Yi, Kyongsu

    2014-07-01

    This paper describes a lateral disturbance compensation algorithm for an application to a motor-driven power steering (MDPS)-based driver assistant system. The lateral disturbance including wind force and lateral load transfer by bank angle reduces the driver's steering refinement and at the same time increases the possibility of an accident. A lateral disturbance compensation algorithm is designed to determine the motor overlay torque of an MDPS system for reducing the manoeuvreing effort of a human driver under lateral disturbance. Motor overlay torque for the compensation of driver's steering torque induced by the lateral disturbance consists of human torque feedback and feedforward torque. Vehicle-driver system dynamics have been investigated using a combined dynamic model which consists of a vehicle dynamic model, driver steering dynamic model and lateral disturbance model. The human torque feedback input has been designed via the investigation of the vehicle-driver system dynamics. Feedforward input torque is calculated to compensate additional tyre self-aligning torque from an estimated lateral disturbance. The proposed compensation algorithm has been implemented on a developed driver model which represents the driver's manoeuvreing characteristics under the lateral disturbance. The developed driver model has been validated with test data via a driving simulator in a crosswind condition. Human-in-the-loop simulations with a full-scale driving simulator on a virtual test track have been conducted to investigate the real-time performance of the proposed lateral disturbance compensation algorithm. It has been shown from simulation studies and human-in-the-loop simulation results that the driver's manoeuvreing effort and a lateral deviation of the vehicle under the lateral disturbance can be significantly reduced via the lateral disturbance compensation algorithm.

  15. Speckle disturbance limit in laser-based cinema projection systems

    Science.gov (United States)

    Verschaffelt, Guy; Roelandt, Stijn; Meuret, Youri; van den Broeck, Wendy; Kilpi, Katriina; Lievens, Bram; Jacobs, An; Janssens, Peter; Thienpont, Hugo

    2015-09-01

    In a multi-disciplinary effort, we investigate the level of speckle that can be tolerated in a laser cinema projector based on a quality of experience experiment with movie clips shown to a test audience in a real-life movie theatre setting. We identify a speckle disturbance threshold by statistically analyzing the observers’ responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. The speckle disturbance limit for movies turns out to be substantially larger than that for still images, and hence is easier to attain.

  16. Hydrological disturbance diminishes predator control in wetlands.

    Science.gov (United States)

    Dorn, Nathan J; Cook, Mark I

    2015-11-01

    Effects of predators on prey populations can be especially strong in aquatic ecosystems, but disturbances may mediate the strength of predator limitation and even allow outbreaks of some prey populations. In a two-year study we investigated the numerical responses of crayfish (Procambarus fallax) and small fishes (Poeciliidae and Fundulidae) to a brief hydrological disturbance in replicated freshwater wetlands with an experimental drying and large predatory fish reduction. The experiment and an in situ predation assay tested the component of the consumer stress model positing that disturbances release prey from predator limitation. In the disturbed wetlands, abundances of large predatory fish were seasonally reduced, similar to dynamics in the Everglades (southern Florida). Densities of small fish were unaffected by the disturbance, but crayfish densities, which were similar across all wetlands before drying, increased almost threefold in the year after the disturbance. Upon re-flooding, juvenile crayfish survival was inversely related to the abundance of large fish across wetlands, but we found no evidence for enhanced algal food quality. At a larger landscape scale (500 km2 of the Everglades), crayfish densities over eight years were positively correlated with the severity of local dry disturbances (up to 99 days dry) during the preceding dry season. In contrast, densities of small-bodied fishes in the same wetlands were seasonally depressed by dry disturbances. The results from our experimental wetland drought and the observations of crayfish densities in the Everglades represent a large-scale example of prey population release following a hydrological disturbance in a freshwater ecosystem. The conditions producing crayfish pulses in the Everglades appear consistent with the mechanics of the consumer stress model, and we suggest crayfish pulses may influence the number of nesting wading birds in the Everglades.

  17. Detection of transient disturbing signals on PC boards

    Directory of Open Access Journals (Sweden)

    S. Korte

    2008-05-01

    Full Text Available This paper shows a possibility to visualize signal propagation in electronic circuits. Instead of using various galvanic measurement points all over the circuit, a test method is shown which measures the radiated field of the printed circuit board. By use of a 2-dimensional positionable field probe it is possible to get an overview over the signals running on the different parts of the PCB. In order to measure transient disturbing signals and distinguish them from normal device operation, problems of probe design and triggering need to be discussed.

  18. Speech and Language Disturbances in Neurology Practice

    Directory of Open Access Journals (Sweden)

    Oğuz Tanrıdağ

    2009-12-01

    Full Text Available Despite the well-known facts discerned from interesting cases of speech and language disturbances over thousands of years, the scientific background and the limitless discussions for nearly 150 years, this field has been considered one of the least important subjects in neurological sciences. In this review, we first analyze the possible causes for this “stepchild” attitude towards this subject and we then summarize the practical aspects concerning speech and language disturbances. Our underlying expectation with this review is to explain the facts concerning those disturbances that might offer us opportunities to better understand the nervous system and the affected patients

  19. Study of ionospheric disturbances over the China mid- and low-latitude region with GPS observations

    Science.gov (United States)

    Ning, Yafei; Tang, Jun

    2018-01-01

    Ionospheric disturbances constitute the main restriction factor for precise positioning techniques based on global positioning system (GPS) measurements. Simultaneously, GPS observations are widely used to determine ionospheric disturbances with total electron content (TEC). In this paper, we present an analysis of ionospheric disturbances over China mid- and low-latitude area before and during the magnetic storm on 17 March 2015. The work analyses the variation of magnetic indices, the amplitude of ionospheric irregularities observed with four arrays of GPS stations and the influence of geomagnetic storm on GPS positioning. The results show that significant ionospheric TEC disturbances occurred between 10:30 and 12:00 UT during the main phase of the large storm, and the static position reliability for this period are little affected by these disturbances. It is observed that the positive and negative disturbances propagate southward along the meridian from mid-latitude to low-latitude regions. The propagation velocity is from about 200 to 700 m s-1 and the amplitude of ionospheric disturbances is from about 0.2 to 0.9 TECU min-1. Moreover, the position dilution of precession (PDOP) with static precise point positioning (PPP) on storm and quiet days is 1.8 and 0.9 cm, respectively. This study is based on the analysis of ionospheric variability with differential rate of vertical TEC (DROVT) and impact of ionospheric storm on positioning with technique of GPS PPP.

  20. Does habitat disturbance affect stress, body condition and parasitism in two sympatric lemurs?

    Science.gov (United States)

    Rakotoniaina, Josué H; Kappeler, Peter M; Ravoniarimbinina, Pascaline; Pechouskova, Eva; Hämäläinen, Anni M; Grass, Juliane; Kirschbaum, Clemens; Kraus, Cornelia

    2016-01-01

    Understanding how animals react to human-induced changes in their environment is a key question in conservation biology. Owing to their potential correlation with fitness, several physiological parameters are commonly used to assess the effect of habitat disturbance on animals' general health status. Here, we studied how two lemur species, the fat-tailed dwarf lemur (Cheirogaleus medius) and the grey mouse lemur (Microcebus murinus), respond to changing environmental conditions by comparing their stress levels (measured as hair cortisol concentration), parasitism and general body condition across four habitats ordered along a gradient of human disturbance at Kirindy Forest, Western Madagascar. These two species previously revealed contrasting responses to human disturbance; whereas M. murinus is known as a resilient species, C. medius is rarely encountered in highly disturbed habitats. However, neither hair cortisol concentrations nor parasitism patterns (prevalence, parasite species richness and rate of multiple infections) and body condition varied across the gradient of anthropogenic disturbance. Our results indicate that the effect of anthropogenic activities at Kirindy Forest is not reflected in the general health status of both species, which may have developed a range of behavioural adaptations to deal with suboptimal conditions. Nonetheless, a difference in relative density among sites suggests that the carrying capacity of disturbed habitat is lower, and both species respond differently to environmental changes, with C. medius being more negatively affected. Thus, even for behaviourally flexible species, extended habitat deterioration could hamper long-term viability of populations.

  1. Wind Power Prediction Considering Nonlinear Atmospheric Disturbances

    Directory of Open Access Journals (Sweden)

    Yagang Zhang

    2015-01-01

    Full Text Available This paper considers the effect of nonlinear atmospheric disturbances on wind power prediction. A Lorenz system is introduced as an atmospheric disturbance model. Three new improved wind forecasting models combined with a Lorenz comprehensive disturbance are put forward in this study. Firstly, we define the form of the Lorenz disturbance variable and the wind speed perturbation formula. Then, different artificial neural network models are used to verify the new idea and obtain better wind speed predictions. Finally we separately use the original and improved wind speed series to predict the related wind power. This proves that the corrected wind speed provides higher precision wind power predictions. This research presents a totally new direction in the wind prediction field and has profound theoretical research value and practical guiding significance.

  2. Anthropogenic disturbance on the vegetation in makurunge

    African Journals Online (AJOL)

    Mgina

    landscape in Tanzania that has been severely affected by anthropogenic disturbance ... Fragmentation of habitats formed patches that have reduced plant species population sizes, and ... by the movement of the Inter-Tropical ..... of pollinators.

  3. Sleep disturbances after non-cardiac surgery

    DEFF Research Database (Denmark)

    Rosenberg, Jacob

    2001-01-01

    . The sleep disturbances seem to be related to the magnitude of trauma and thereby to the surgical stress response and/or post-operative opioid administration. Post-operative sleep disturbances may contribute to the development of early post-operative fatigue, episodic hypoxaemia, haemodynamic instability......After major non-cardiac surgery sleep pattern is usually disturbed with initial suppression of rapid eye movement sleep with a subsequent rebound during the first post-operative week. Deep sleep is also suppressed for several days after the operation and subjective sleep quality is impaired...... and altered mental status, all with a potential negative effect on post-operative outcome. Minimizing surgical trauma and avoiding or minimizing use of opioids for pain relief may prevent or reduce post-operative sleep disturbances. Post-operative sleep pattern represents an important research field, since...

  4. Vibration Disturbance Damping System Design to Protect Payload of the Rocket

    Directory of Open Access Journals (Sweden)

    Sutisno Sutisno

    2012-12-01

    Full Text Available Rocket motor generates vibrations acting on whole rocket body including its contents. Part of the body which is sensitive to disturbance is the rocket payload. The payload consists of various electronic instruments including: transmitter, various sensors, accelerometer, gyro, the embedded controller system, and others. This paper presents research on rocket vibration influence to the payload and the method to avoid disturbance. Avoiding influence of vibration disturbance can be done using silicone gel material whose typical damping factors are relatively high. The rocket vibration was simulated using electromagnetic motor, and the vibrations were measured using an accelerometer sensor. The measurement results were displayed in the form of curve, indicating the vibration level on some parts of the tested material. Some measurement results can be applied to determine the good material to attenuate vibration disturbance on the instruments of the payload.

  5. Evaluating disturbance on mediterranean karst areas: the example of Sardinia (Italy)

    Science.gov (United States)

    de Waele, Jo

    2009-07-01

    Evaluating the human disturbance on karst areas is a difficult task because of the complexity of these peculiar and unique environments. The human impact on karstic geo-ecosystems is increasingly important and there is an increasing need for multidisciplinary tools to assess the environmental changes in karst areas. Many disciplines, such as biology, geomorphology, hydrology and social-economical sciences are to be considered to sufficiently evaluate the impact on these intrinsically vulnerable areas. This article gives an overview of the evolution of environmental impact on karst areas of the island Sardinia (Italy). For this particular case, the most important impacts in the past 50 years are derived from the following activities, in decreasing importance: (1) mining and quarrying; (2) deforestation, agriculture and grazing; (3) building (widespread urbanisation, isolated homes, etc.) and related infrastructures (roads, sewer systems, aqueducts, waste dumps, etc.); (4) tourism; (5) military activities. To evaluate the present environmental state of these areas the Disturbance Index for Karst environments [Van Beynen and Townsend (Environ Manage 36:101-116)] is applied in a slightly modified version. Instead of considering the indicators of environmental disturbances used in the original method, this slightly modified index evaluates the disturbances causing the deterioration of the environmental attributes. In the Sardinian case study, 27 disturbances have been evaluated, giving rise to the definition of a Disturbance Index ranging between 0 (Pristine) and 1 (highly disturbed). This Disturbance Index simplifies the original KDI method, appears to adequately measure disturbance on Mediterranean karst areas and could be applied with success to other similar regions.

  6. Application of electronic business in monitoring marketing and consumption of human medicines in the Republic of Serbia

    Directory of Open Access Journals (Sweden)

    Tešić Danka

    2011-01-01

    Full Text Available The paper describes the application of electronic business (e-business in monitoring marketing and consumption of medicines, as one of e-government services (e-services of the Republic of Serbia (Serbia. It shows methodological framework for development of e-services, through use of RUP (Rational Unified Process methodology. The Unified Modelling Language (UML notation was used for description of the system model. The paper presents modeling of the process of marketing of medications for human use, as well as development of the information subsystem underpinning it. The analysis of the marketing of medications in Serbia was carried out in 2006, 2007, 2008 and 2009, by the Medicines and Medical Devices Agency of Serbia, which was authorized to collect and analyze data on the marketing and consumption of medicines and medical devices. Data gathered for a particular time period were analyzed using Anatomical Therapeutic Chemical Classification and the Defined Daily Doses methodology. The amount of medicines consumed was translated into the DDD by 1000 individuals per day, and gave an insight into the number of individuals (out of 1000 who used the medicine under observation and were under its effect during a single day. The data extracted are correlated with the number of individuals who took the medication during the period under observation. In the year 2006 total marketing of medications for human use amounted to € 510.833.609,54, in 2007 it stood at € 687.588.174,80, in 2008 it was € 799.082.221,05, while the overall marketing of medicines in the year 2009 was € 741.981.960,19. By processing the data by methodology of DDD, the following results were obtained: 1013,70 DDD/1000 individuals/day in year 2006; in year 2007, 1084,34 DDD/1000 individuals/day; in year 2008, 1219,57 DDD/1000 individuals/day and in year 2009, 1177,72 DDD/1000 individuals/day. The implementation of such system produces a series of technological, functional and

  7. Effects of tobacco smoke and electronic cigarette vapor exposure on the oral and gut microbiota in humans: a pilot study.

    Science.gov (United States)

    Stewart, Christopher J; Auchtung, Thomas A; Ajami, Nadim J; Velasquez, Kenia; Smith, Daniel P; De La Garza, Richard; Salas, Ramiro; Petrosino, Joseph F

    2018-01-01

    The use of electronic cigarettes (ECs) has increased drastically over the past five years, primarily as an alternative to smoking tobacco cigarettes. However, the adverse effects of acute and long-term use of ECs on the microbiota have not been explored. In this pilot study, we sought to determine if ECs or tobacco smoking alter the oral and gut microbiota in comparison to non-smoking controls. We examined a human cohort consisting of 30 individuals: 10 EC users, 10 tobacco smokers, and 10 controls. We collected cross-sectional fecal, buccal swabs, and saliva samples from each participant. All samples underwent V4 16S rRNA gene sequencing. Tobacco smoking had a significant effect on the bacterial profiles in all sample types when compared to controls, and in feces and buccal swabs when compared to EC users. The most significant associations were found in the gut, with an increased relative abundance of Prevotella ( P = 0.006) and decreased Bacteroides ( P = 0.036) in tobacco smokers. The Shannon diversity was also significantly reduced ( P = 0.009) in fecal samples collected from tobacco smokers compared to controls. No significant difference was found in the alpha diversity, beta-diversity or taxonomic relative abundances between EC users and controls. From a microbial ecology perspective, the current pilot data demonstrate that the use of ECs may represent a safer alternative compared to tobacco smoking. However, validation in larger cohorts and greater understanding of the short and long-term impact of EC use on microbiota composition and function is warranted.

  8. Effects of tobacco smoke and electronic cigarette vapor exposure on the oral and gut microbiota in humans: a pilot study

    Directory of Open Access Journals (Sweden)

    Christopher J. Stewart

    2018-04-01

    Full Text Available Background The use of electronic cigarettes (ECs has increased drastically over the past five years, primarily as an alternative to smoking tobacco cigarettes. However, the adverse effects of acute and long-term use of ECs on the microbiota have not been explored. In this pilot study, we sought to determine if ECs or tobacco smoking alter the oral and gut microbiota in comparison to non-smoking controls. Methods We examined a human cohort consisting of 30 individuals: 10 EC users, 10 tobacco smokers, and 10 controls. We collected cross-sectional fecal, buccal swabs, and saliva samples from each participant. All samples underwent V4 16S rRNA gene sequencing. Results Tobacco smoking had a significant effect on the bacterial profiles in all sample types when compared to controls, and in feces and buccal swabs when compared to EC users. The most significant associations were found in the gut, with an increased relative abundance of Prevotella (P = 0.006 and decreased Bacteroides (P = 0.036 in tobacco smokers. The Shannon diversity was also significantly reduced (P = 0.009 in fecal samples collected from tobacco smokers compared to controls. No significant difference was found in the alpha diversity, beta-diversity or taxonomic relative abundances between EC users and controls. Discussion From a microbial ecology perspective, the current pilot data demonstrate that the use of ECs may represent a safer alternative compared to tobacco smoking. However, validation in larger cohorts and greater understanding of the short and long-term impact of EC use on microbiota composition and function is warranted.

  9. In vitro human epidermal permeation of nicotine from electronic cigarette refill liquids and implications for dermal exposure assessment.

    Science.gov (United States)

    Frasch, H Frederick; Barbero, Ana M

    2017-11-01

    Nicotine plus flavorings in a propylene glycol (PG) vehicle are the components of electronic cigarette liquids (e-liquids), which are vaporized and inhaled by the user. Dermal exposure to nicotine and e-liquids may occur among workers in mixing and filling of e-cigarettes in the manufacturing process. Inadvertent skin contact among consumers is also a concern. In vitro nicotine permeation studies using heat-separated human epidermis were performed with surrogate and two commercial e-liquids, neat and aqueous nicotine donor formulations. Steady-state fluxes (J ss ), and lag times (t lag ) were measured for each formulation. In addition, transient (4 h) exposure and finite dose (1-10 μl/cm 2 ) experiments were undertaken using one commercial e-liquid. Average J ss (μg/cm 2 /h) from formulations were: nicotine in PG (24 mg/ml): 3.97; commercial e-liquid containing menthol (25 mg/ml nicotine): 10.2; commercial e-liquid containing limonene (25 mg/ml nicotine): 23.7; neat nicotine: 175. E-liquid lag times ranged from 5 to 10 h. Absorbed fraction of nicotine from finite doses was ≈0.3 at 48 h. The data were applied to transient exposure and finite dose dermal exposure assessment models and to a simple pharmacokinetic model. Three illustrative exposure scenarios demonstrate use of the data to predict systemic uptake and plasma concentrations from dermal exposure. The data demonstrate the potential for significant nicotine absorption through skin contact with e-cigarette refill solutions and the neat nicotine used to mix them.

  10. Topographic assessment of human enamel surface treated with different topical sodium fluoride agents: Scanning electron microscope consideration

    Directory of Open Access Journals (Sweden)

    Gurlal Singh Brar

    2017-01-01

    Full Text Available Introduction: Continuous balanced demineralization and remineralization are natural dynamic processes in enamel. If the balance is interrupted and demineralization process dominates, it may eventually lead to the development of carious lesions in enamel and dentine. Fluoride helps control decay by enhancing remineralization and altering the structure of the tooth, making the surface less soluble. Methodology: One hundred and twenty sound human permanent incisors randomly and equally distributed into six groups as follows: Group I - Control, II - Sodium fluoride solution, III - Sodium fluoride gel, IV - Sodium fluoride varnish, V - Clinpro Tooth Crème (3M ESPE, and VI-GC Tooth Mousse Plus or MI Paste Plus. The samples were kept in artificial saliva for 12 months, and the topical fluoride agents were applied to the respective sample groups as per the manufacturer instructions. Scanning electron microscope (SEM evaluation of all the samples after 6 and 12 months was made. Results: Morphological changes on the enamel surface after application of fluoride in SEM revealed the presence of globular precipitate in all treated samples. Amorphous, globular, and crystalline structures were seen on the enamel surface of the treated samples. Clear differences were observed between the treated and untreated samples. Conclusion: Globular structures consisting of amorphous CaF2precipitates, which acted as a fluoride reservoir, were observed on the enamel surface after action of different sodium fluoride agents. CPP-ACPF (Tooth Mousse and Tricalcium phosphate with fluoride (Clinpro tooth crème are excellent delivery vehicles available in a slow release amorphous form to localize fluoride at the tooth surface.

  11. The human and fire connection

    Science.gov (United States)

    Theresa B. Jain

    2014-01-01

    We refer to fire as a natural disturbance, but unlike other disturbances such as forest insects and diseases, fire has had an intimate relationship with humans. Fire facilitated human evolution over two million years ago when our ancestors began to use fire to cook. Fire empowered our furbearers to adapt to cold climates, allowing humans to disperse and settle into...

  12. Comparison of electron microscopy, enzyme-linked immunosorbent assay, solid-phase radioimmunoassay, and indirect immunofluorescence for detection of human rotavirus antigen in faeces

    Energy Technology Data Exchange (ETDEWEB)

    Birch, C J; Lehmann, N I; Hawker, A J; Marshall, J A; Gust, I D [Fairfield Hospital for Communicable Diseases, Victoria (Australia). Virology Dept.

    1979-07-01

    Four techniques were compared for their practicability, speed, and sensitivity for the detection of human rotavirus. Radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) were found to be the most sensitive means of identifying rotavirus and, once processed, up to 40 specimens could be examined daily. Electron microscopy, although less sensitive than these techniques, had the advantage of being able to detect other viral agents present in faecal extracts. Indirect immunofluorescence failed to detect rotavirus as often as the other three methods. In laboratories where routine examination of faecal specimens from patients with gastroenteritis is required, ELISA and RIA are useful alternatives to electron microscopy.

  13. Comparison of electron microscopy, enzyme-linked immunosorbent assay, solid-phase radioimmunoassay, and indirect immunofluorescence for detection of human rotavirus antigen in faeces

    International Nuclear Information System (INIS)

    Birch, C.J.; Lehmann, N.I.; Hawker, A.J.; Marshall, J.A.; Gust, I.D.

    1979-01-01

    Four techniques were compared for their practicability, speed, and sensitivity for the detection of human rotavirus. Radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) were found to be the most sensitive means of identifying rotavirus and, once processed, up to 40 specimens could be examined daily. Electron microscopy, although less sensitive than these techniques, had the advantage of being able to detect other viral agents present in faecal extracts. Indirect immunofluorescence failed to detect rotavirus as often as the other three methods. In laboratories where routine examination of faecal specimens from patients with gastroenteritis is required, ELISA and RIA are useful alternatives to electron microscopy. (author)

  14. The intermediate disturbance hypothesis applies to tropical forests, but disturbance contributes little to tree diversity.

    Science.gov (United States)

    Bongers, Frans; Poorter, Lourens; Hawthorne, William D; Sheil, Douglas

    2009-08-01

    The intermediate disturbance hypothesis (IDH) predicts local species diversity to be maximal at an intermediate level of disturbance. Developed to explain species maintenance and diversity patterns in species-rich ecosystems such as tropical forests, tests of IDH in tropical forest remain scarce, small-scale and contentious. We use an unprecedented large-scale dataset (2504 one-hectare plots and 331,567 trees) to examine whether IDH explains tree diversity variation within wet, moist and dry tropical forests, and we analyse the underlying mechanism by determining responses within functional species groups. We find that disturbance explains more variation in diversity of dry than wet tropical forests. Pioneer species numbers increase with disturbance, shade-tolerant species decrease and intermediate species are indifferent. While diversity indeed peaks at intermediate disturbance levels little variation is explained outside dry forests, and disturbance is less important for species richness patterns in wet tropical rain forests than previously thought.

  15. Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.

    Science.gov (United States)

    Makihara, Yukiko; Segal, Richard L; Wolpaw, Jonathan R; Thompson, Aiko K

    2014-09-15

    In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion. Copyright © 2014 the American Physiological Society.

  16. Peatlands of the Peruvian Puna ecoregion: types, characteristics and disturbance

    Directory of Open Access Journals (Sweden)

    F. Salvador

    2014-05-01

    Full Text Available Peatlands represent one of the most important water resources in the Puna grassland ecoregion, but this fact is not yet widely recognised. Puna peatlands also provide key environmental services such as increasing the regional biodiversity of the Andean Altiplano plateau and contributing to the wellbeing of high-altitude human populations by providing grazing land and cooking fuel. We conducted a study in the Peruvian Puna ecoregion to describe the current condition of peatlands in terms of their vegetation, physical and chemical characteristics and disturbance status. Our results suggest that peat thickness, organic matter and degree of humification are good indicators for identifying peatlands in the Puna ecoregion. In general, the peatland sites that we sampled were dominated by mixtures of cushion and acaulescent rosette forming plants such as Distichia muscoides Nees & Meyen and Plantago tubulosa Decne. These Distichia and Plantago peatland sites were characterised by a mean surface water pH of 6.3, corrected electrical conductivity (K corr. in the range 300–1814 μS cm-1 and presented the following mean exchangeable cation values: Ca2+ 48 mg L-1, Mg2+ 9.6 mg L-1, Na+ 8.2 mg L-1 and K+ 2.1 mg L-1. The most common causes of disturbance we encountered were grazing, peat extraction and roads. Disturbance was most severe in mining sites, where peatlands are especially vulnerable because they are not under legal protection.

  17. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.

    1996-01-01

    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  18. Propagation speed and incident direction of transient ionospheric disturbance (TID)

    International Nuclear Information System (INIS)

    Maeda, Sawako; Handa, Shun.

    1978-01-01

    It is well known that large scale transient ionospheric disturbance (ls-TID) of period from 20 min to 3 hours and spatial wave length from hundreds to thousands km among TID's is in close correlation to geomagnetic activity at high latitude. Since TID well agrees with the wave characteristic of internal gravitational waves, it has come to be considered that the internal gravitational waves excited by Lorentz's force and joule heating due to the ionospheric current in auroral zone at the time of substorm cause disturbances to ionosphere electron density. The authors have examined the propagation speed and incident direction of TID using the data observed at 5 min intervals of maximum electron density in F layer during IGY (international geophysical year). The data was processed through a band pass filter because only the waves with period from 20 min to 3 hours were required. Since two proposed modes for ls-TID have been discussed, whose dispersion properties are different, it is necessary to determine the propagation characteristics of ls-TID by observation, and to clarify the propagation mechanism of internal gravitational waves. Therefore, the dependence of propagation speed on period has been investigated. It is concluded that ls-TID was observed at the time of polar magnetic field disturbances, the average propagation speed was about 500 m/s and the incident direction was north-north east for the variation of from 20 min to 3 hours, and as for the dependence of propagation speed on period, the average speed was about 670 m/s for the long period change (approximately 100 min period), and about 440 m/s for short period change (approximately 30 min period) and the dispersion was observed. (Wakatsuki, Y.)

  19. Reconstructing disturbance history for an intensively mined region by time-series analysis of Landsat imagery.

    Science.gov (United States)

    Li, Jing; Zipper, Carl E; Donovan, Patricia F; Wynne, Randolph H; Oliphant, Adam J

    2015-09-01

    Surface mining disturbances have attracted attention globally due to extensive influence on topography, land use, ecosystems, and human populations in mineral-rich regions. We analyzed a time series of Landsat satellite imagery to produce a 28-year disturbance history for surface coal mining in a segment of eastern USA's central Appalachian coalfield, southwestern Virginia. The method was developed and applied as a three-step sequence: vegetation index selection, persistent vegetation identification, and mined-land delineation by year of disturbance. The overall classification accuracy and kappa coefficient were 0.9350 and 0.9252, respectively. Most surface coal mines were identified correctly by location and by time of initial disturbance. More than 8 % of southwestern Virginia's >4000-km(2) coalfield area was disturbed by surface coal mining over the 28-year period. Approximately 19.5 % of the Appalachian coalfield surface within the most intensively mined county (Wise County) has been disturbed by mining. Mining disturbances expanded steadily and progressively over the study period. Information generated can be applied to gain further insight concerning mining influences on ecosystems and other essential environmental features.

  20. Long Short-Term Memory Neural Networks for Online Disturbance Detection in Satellite Image Time Series

    Directory of Open Access Journals (Sweden)

    Yun-Long Kong

    2018-03-01

    Full Text Available A satellite image time series (SITS contains a significant amount of temporal information. By analysing this type of data, the pattern of the changes in the object of concern can be explored. The natural change in the Earth’s surface is relatively slow and exhibits a pronounced pattern. Some natural events (for example, fires, floods, plant diseases, and insect pests and human activities (for example, deforestation and urbanisation will disturb this pattern and cause a relatively profound change on the Earth’s surface. These events are usually referred to as disturbances. However, disturbances in ecosystems are not easy to detect from SITS data, because SITS contain combined information on disturbances, phenological variations and noise in remote sensing data. In this paper, a novel framework is proposed for online disturbance detection from SITS. The framework is based on long short-term memory (LSTM networks. First, LSTM networks are trained by historical SITS. The trained LSTM networks are then used to predict new time series data. Last, the predicted data are compared with real data, and the noticeable deviations reveal disturbances. Experimental results using 16-day compositions of the moderate resolution imaging spectroradiometer (MOD13Q1 illustrate the effectiveness and stability of the proposed approach for online disturbance detection.

  1. Effects of climate change and anthropogenic modification on a disturbance-dependent species in a large riverine system

    Science.gov (United States)

    Zeigler, Sara; Catlin, Daniel H.; Bomberger Brown, M.; Fraser, J.D.; Dinan, Lauren R.; Hunt, Kelsi L.; Jorgensen, Joel G.; Karpanty, Sarah M.

    2017-01-01

    Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the

  2. Speckle perception and disturbance limit in laser based projectors

    Science.gov (United States)

    Verschaffelt, Guy; Roelandt, Stijn; Meuret, Youri; Van den Broeck, Wendy; Kilpi, Katriina; Lievens, Bram; Jacobs, An; Janssens, Peter; Thienpont, Hugo

    2016-04-01

    We investigate the level of speckle that can be tolerated in a laser cinema projector. For this purpose, we equipped a movie theatre room with a prototype laser projector. A group of 186 participants was gathered to evaluate the speckle perception of several, short movie trailers in a subjective `Quality of Experience' experiment. This study is important as the introduction of lasers in projection systems has been hampered by the presence of speckle in projected images. We identify a speckle disturbance threshold by statistically analyzing the observers' responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. As is also discussed in [Verschaffelt et al., Scientific Reports 5, art. nr. 14105, 2015] we find that, for moving images, the speckle becomes disturbing if the speckle contrast becomes larger than 6.9% for the red, 6.0% for the green, and 4.8% for the blue primary colors of the projector, whereas for still images the speckle detection threshold is about 3%. As we could not independently tune the speckle contrast of each of the primary colors, this speckle disturbance limit seems to be determined by the 6.9% speckle contrast of the red color as this primary color contains the largest amount of speckle. The speckle disturbance limit for movies thus turns out to be substantially larger than that for still images, and hence is easier to attain.

  3. Effect of 60Co γ-ray irradiation on cytoskeleton of human peripheral blood monocytes with whole mount cell electron microscopy in vitro

    International Nuclear Information System (INIS)

    Chen Xiaomei; Guo Yuhua; Yin Zhiwei

    1992-01-01

    Whole mount cell electron microscopy was used in combination with selective extraction to prepare cytoskeletal framework. Cytoskeleton prepared by Triton X-100 treatment of human peripheral blood monocytes appeared on electron microscopy as a highly organized and interconnected three-dimensional matrix of different fibrous elements. By three-dimensional visualization of Triton X-100 resistant cytoskeletons it was demonstrated that different doses of 60 Co γ-rays caused distinctive and reproducible alterations of the cytoskeleton of intact human peripheral blood monocytes in vitro. The alterations were similar to those caused by cytochalasin B and by colchicine. From these observations and other workers'studies, it is presumed that 60 Co γ-ray irradiation may inhibit cytoplasmic microtubule and microfilament assembling

  4. The Human-Electronic Crew: Can We Trust the Team? Proceedings of the 3rd International Workshop on Human-Computer Teamwork

    National Research Council Canada - National Science Library

    Taylor, Robert

    1995-01-01

    ...-Electronic Crew Team's decisions. Many of the decisions that the Team is required to make occur in an imprecise world in which the judgements may be made based on such vague concepts as high, low, near or far...

  5. Assessment of disturbance at three spatial scales in two large tropical reservoirs

    Directory of Open Access Journals (Sweden)

    Letícia de Morais

    2016-12-01

    Full Text Available Large reservoirs are an increasingly common feature across tropical landscapes because of their importance for water supply, flood control and hydropower, but their ecological conditions are infrequently evaluated. Our objective was to assess the range of disturbances for two large tropical reservoirs and their influences on benthic macroinvertebrates. We tested three hypotheses: i a wide variation in the level of environmental disturbance can be observed among sites in the reservoirs; ii the two reservoirs would exhibit a different degree of disturbance level; and iii the magnitude of disturbance would influence the structure and composition of benthic assemblages. For each reservoir, we assessed land use (macroscale, physical habitat structure (mesoscale, and water quality (microscale. We sampled 40 sites in the littoral zones of both Três Marias and São Simão Reservoirs (Minas Gerais, Brazil. At the macroscale, we measured cover percentages of land use categories in buffer areas at each site, where each buffer was a circular arc of 250 m. At the mesoscale, we assessed the presence of human disturbances in the riparian and drawdown zones at the local (site scale. At the microscale, we assessed water quality at each macroinvertebrate sampling station using the Micro Disturbance Index (MDI. To evaluate anthropogenic disturbance of each site, we calculated an integrated disturbance index (IDI from a buffer disturbance index (BDI and a local disturbance index (LDI. For each site, we calculated richness and abundance of benthic macroinvertebrates, Chironomidae genera richness, abundance and percent Chironomidae individuals, abundance and percent EPT individuals, richness and percent EPT taxa, abundance and percent resistant individuals, and abundance and percent non-native individuals. We also evaluated the influence of disturbance on benthic macroinvertebrate assemblages at the entire-reservoir scale. The BDI, LDI and IDI had significantly

  6. Disturbance attenuation of nonlinear control systems using an observer-based fuzzy feedback linearization control

    International Nuclear Information System (INIS)

    Chen, C.-C.; Hsu, C.-H.; Chen, Y.-J.; Lin, Y.-F.

    2007-01-01

    The almost disturbance decoupling and trajectory tracking of nonlinear control systems using an observer-based fuzzy feedback linearization control (FLC) is developed. Because not all of the state variables of the nonlinear dynamic equations are available, a nonlinear state observer is employed to estimate the state variables. The feedback linearization control guarantees the almost disturbance decoupling performance and the uniform ultimate bounded stability of the tracking error system. Once the tracking errors are driven to touch the global final attractor with the desired radius, the fuzzy logic control is immediately applied via human expert's knowledge to improve the convergence rate. One example, which cannot be solved by the first paper on the almost disturbance decoupling problem, is proposed in this paper to exploit the fact that the tracking and the almost disturbance decoupling performances are easily achieved by our proposed approach. In order to demonstrate the practical applicability, the study has investigated a pendulum control system

  7. Active disturbance rejection controller for chemical reactor

    International Nuclear Information System (INIS)

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I.

    2015-01-01

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method

  8. Active disturbance rejection controller for chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I., E-mail: roxana.both@aut.utcluj.ro [Technical University of Cluj-Napoca, 400114 Cluj-Napoca (Romania)

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  9. Penelope simulation of electron beams 6 MeV from a linear accelerator for studies in different materials equivalent to human body

    International Nuclear Information System (INIS)

    Apaza V, D.; Cardena R, R.; Cayllahua Q, F.; Vega R, J.; Urquizo B, R.

    2015-10-01

    In systems of radiotherapy treatment for cancer, always looking to maximize the radiation dose on the target (tumor) and minimize to the organs at risk or healthy, so they resort to using electron beams that have properties and characteristics of higher dose deposition at fixed depths, directing and focusing the higher dose in the tumor, without harming healthy tissues to which seeks to radiate in the least possible. Simulating the interaction of electron beams with different equivalent tissues to the human body leads to a better dosimetric evaluation, improving the quality of treatment planning. The aim of this study is the comparison from the characterization of several equivalent tissues to the human body such as soft tissue, bone and lung. Based on the simulation of a calibration beam in water phantom with Penelope code and compared with the results of the calibration curves of beams in water vat by a linear accelerator Elekta Synergy of Hospital Nacional Carlos Alberto Seguin Escobedo EsSalud of Arequipa (Peru). From this to evaluate the behavior of electron beams in a homogeneous medium and then further evaluation in the human body homogeneities, for better evaluation and specific treatment planning. (Author)

  10. Is coral richness related to community resistance to and recovery from disturbance?

    Directory of Open Access Journals (Sweden)

    Stacy Y. Zhang

    2014-03-01

    Full Text Available More diverse communities are thought to be more stable—the diversity–stability hypothesis—due to increased resistance to and recovery from disturbances. For example, high diversity can make the presence of resilient or fast growing species and key facilitations among species more likely. How natural, geographic biodiversity patterns and changes in biodiversity due to human activities mediate community-level disturbance dynamics is largely unknown, especially in diverse systems. For example, few studies have explored the role of diversity in tropical marine communities, especially at large scales. We tested the diversity–stability hypothesis by asking whether coral richness is related to resistance to and recovery from disturbances including storms, predator outbreaks, and coral bleaching on tropical coral reefs. We synthesized the results of 41 field studies conducted on 82 reefs, documenting changes in coral cover due to disturbance, across a global gradient of coral richness. Our results indicate that coral reefs in more species-rich regions were marginally less resistant to disturbance and did not recover more quickly. Coral community resistance was also highly dependent on pre-disturbance coral cover, probably due in part to the sensitivity of fast-growing and often dominant plating acroporid corals to disturbance. Our results suggest that coral communities in biodiverse regions, such as the western Pacific, may not be more resistant and resilient to natural and anthropogenic disturbances. Further analyses controlling for disturbance intensity and other drivers of coral loss and recovery could improve our understanding of the influence of diversity on community stability in coral reef ecosystems.

  11. Tree species diversity mitigates disturbance impacts on the forest carbon cycle.

    Science.gov (United States)

    Silva Pedro, Mariana; Rammer, Werner; Seidl, Rupert

    2015-03-01

    Biodiversity fosters the functioning and stability of forest ecosystems and, consequently, the provision of crucial ecosystem services that support human well-being and quality of life. In particular, it has been suggested that tree species diversity buffers ecosystems against the impacts of disturbances, a relationship known as the "insurance hypothesis". Natural disturbances have increased across Europe in recent decades and climate change is expected to amplify the frequency and severity of disturbance events. In this context, mitigating disturbance impacts and increasing the resilience of forest ecosystems is of growing importance. We have tested how tree species diversity modulates the impact of disturbance on net primary production and the total carbon stored in living biomass for a temperate forest landscape in Central Europe. Using the simulation model iLand to study the effect of different disturbance regimes on landscapes with varying levels of tree species richness, we found that increasing diversity generally reduces the disturbance impact on carbon storage and uptake, but that this effect weakens or even reverses with successional development. Our simulations indicate a clear positive relationship between diversity and resilience, with more diverse systems experiencing lower disturbance-induced variability in their trajectories of ecosystem functioning. We found that positive effects of tree species diversity are mainly driven by an increase in functional diversity and a modulation of traits related to recolonization and resource usage. The results of our study suggest that increasing tree species diversity could mitigate the effects of intensifying disturbance regimes on ecosystem functioning and improve the robustness of forest carbon storage and the role of forests in climate change mitigation.

  12. Is coral richness related to community resistance to and recovery from disturbance?

    Science.gov (United States)

    Zhang, Stacy Y; Speare, Kelly E; Long, Zachary T; McKeever, Kimberly A; Gyoerkoe, Megan; Ramus, Aaron P; Mohorn, Zach; Akins, Kelsey L; Hambridge, Sarah M; Graham, Nicholas A J; Nash, Kirsty L; Selig, Elizabeth R; Bruno, John F

    2014-01-01

    More diverse communities are thought to be more stable-the diversity-stability hypothesis-due to increased resistance to and recovery from disturbances. For example, high diversity can make the presence of resilient or fast growing species and key facilitations among species more likely. How natural, geographic biodiversity patterns and changes in biodiversity due to human activities mediate community-level disturbance dynamics is largely unknown, especially in diverse systems. For example, few studies have explored the role of diversity in tropical marine communities, especially at large scales. We tested the diversity-stability hypothesis by asking whether coral richness is related to resistance to and recovery from disturbances including storms, predator outbreaks, and coral bleaching on tropical coral reefs. We synthesized the results of 41 field studies conducted on 82 reefs, documenting changes in coral cover due to disturbance, across a global gradient of coral richness. Our results indicate that coral reefs in more species-rich regions were marginally less resistant to disturbance and did not recover more quickly. Coral community resistance was also highly dependent on pre-disturbance coral cover, probably due in part to the sensitivity of fast-growing and often dominant plating acroporid corals to disturbance. Our results suggest that coral communities in biodiverse regions, such as the western Pacific, may not be more resistant and resilient to natural and anthropogenic disturbances. Further analyses controlling for disturbance intensity and other drivers of coral loss and recovery could improve our understanding of the influence of diversity on community stability in coral reef ecosystems.

  13. The intermediate disturbance hypothesis applies to tropical forests, but disturbance contributes little to tree diversity

    NARCIS (Netherlands)

    Bongers, F.; Poorter, L.; Hawthorne, W.D.; Sheil, D.

    2009-01-01

    The intermediate disturbance hypothesis (IDH) predicts local species diversity to be maximal at an intermediate level of disturbance. Developed to explain species maintenance and diversity patterns in species-rich ecosystems such as tropical forests, tests of IDH in tropical forest remain scarce,

  14. Visually Determined Soil Disturbance Classes Used as Indices of Forest Harvesting Disturbance

    Science.gov (United States)

    W. Michael Aust; James A. Burger; Emily A. Carter; David P. Preston; Steven C. Patterson

    1998-01-01

    Visual estimates of soil and site disturbances are used by foresters, soil scientists, logging supervisors. and machinery operators to minimize harvest disturbances to forest sites, to evaluate compliance with forestry Best Management Practices (BMPs), and to determine the need for ameliorative practices such as tnechanical site preparation. Although estimates are...

  15. Language disturbances from mesencephalo-thalamic infarcts

    International Nuclear Information System (INIS)

    Lazzarino, L.G.; Nicolai, A.; Valassi, F.; Biasizzo, E.

    1991-01-01

    The authors report the cases of two patients with CT-documented paramedian mesencephalo-thalamic infarcts, showing language disturbances. The first patient showed a non fluent, transcortical motor-like aphasia, the other had a fluent but severely paraphasic language disorder. The CT study disclosed that it was the dorso-median thalamic nucleus that was mostly involved in both cases. These findings agree with a few previous pathological studies suggesting that the paramedian thalamic nuclei, particlularly the dorso-median nucleus may play some role in language disturbances. However the anatomical basis for thalamic aphasia remains speculative, taking into account the importantce of cortical connections in the origin of subcortical neuropsychological disturbances. (orig.)

  16. Diagnostic orientation in control of disturbance situations

    International Nuclear Information System (INIS)

    Hukki, K.; Norros, L.

    1993-01-01

    The object of the study is diagnostic judgement in the control of dynamic processes. The starting point was the known difficulty process operators have in utilizing knowledge of process dynamics in disturbance situations that require both diagnostic and prognostic actions. A model of the diagnostic judgement process as a construction of coherent interpretation of the situation is outlined, and comprehensive data from simulated disturbance handling by 6 crews of a PWR type nuclear power plant was analysed. The phase of analysis included evaluation of the adequacy of task performance, utilization of available process information, and evaluation of the interpretation of disturbance situations. The results suggest that a functional orientation towards task performance allows a more coherent and comprehensive interpretation of the situation and more adequate task performance. Coherence of interpretation seems to be reflected in a higher subjective certainty compared with crews with an incoherent interpretation. (author). 15 refs, 2 figs, 2 tabs

  17. Psychopathology and hormonal disturbances in eating disorders

    Directory of Open Access Journals (Sweden)

    Pierpaola D’Arista

    2008-09-01

    Full Text Available

    Background: Our aim was to study the relationship between hormonal disturbances and psychopathology in Eating Disorders (ED.

    Methods: Forty-nine women diagnosed as Eating Disorders according to DSM-IV were subjected to control plasma levels of TSH, FT3, FT4, LH, FSH, 17beta-estradiol, prolactin, cortisol, DHEAS, GH and IGF-1. They were also administered by SCL-90R, BAT, DES II questionnaires. We applied multivariate regression models.

    Results: Our results highlight a statistically significant relation between LH, FSH and prolactin decreased levels, mood and thought disturbances (subscales 3, 5, 7, 8 and 9 of SCL-90r which are associated to Body Attitude ( BAT total scale and Dissociative Experiences (DES II total scale.

    Conclusions: Decreased sexual hormones levels could have a role in ED psychological disturbances, not inquired yet

  18. Thermoluminescent Signals Caused by Disturbing Effects

    International Nuclear Information System (INIS)

    German, U.; Weinstein, M.; Ben-Shachar, B.

    1999-01-01

    One of the major sources of uncertainty in the measurement of low radiation doses by means of thermoluminescence dosemeters is the presence of disturbing thermoluminescence signals, especially luminescence caused by visible light, and by materials attached to the heated areas. Glow curves of thermoluminescence dosemeters contain useful information that can improve the accuracy and the reliability of the thermoluminescent measurements. The influence of the various disturbing effects can be recognised in the shape of the glow curves and can sometimes be separated from the exposure. Some examples are presented of signals arising from the two disturbing effects mentioned above, the signal contributed by Teflon used in the TLD-100 cards of Bicron/Harshaw and some abnormal glow curves due to dirt attached to the cards. Subtraction of the contributions due to these effects is suggested to obtain the net exposure signal. (author)

  19. Work Time Control and Sleep Disturbances

    DEFF Research Database (Denmark)

    Salo, Paula; Ala-Mursula, Leena; Rod, Naja Hulvej

    2014-01-01

    OBJECTIVES: Employee control over work times has been associated with favorable psychosocial and health-related outcomes, but the evidence regarding sleep quality remains inconclusive. We examined cross-sectional and prospective associations between work time control and sleep disturbances...... in a large working population, taking into account total hours worked. METHODS: The data were from a full-panel longitudinal cohort study of Finnish public sector employees who responded to questions on work time control and sleep disturbances in years 2000-2001, 2004-2005, 2008-2009, and 2012. The analysis....... RESULTS: Consistently in both cross-sectional and longitudinal models, less control over work time was associated with greater sleep disturbances in the total population and among those working normal 40-hour weeks. Among participants working more than 40 hours a week, work time that was both very high...

  20. North American forest disturbance mapped from a decadal Landsat record

    Science.gov (United States)

    Jeffrey G. Masek; Chengquan Huang; Robert Wolfe; Warren Cohen; Forrest Hall; Jonathan Kutler; Peder. Nelson

    2008-01-01

    Forest disturbance and recovery are critical ecosystem processes, but the spatial pattern of disturbance has never been mapped across North America. The LEDAPS (Landsat Ecosystem Disturbance Adaptive Processing System) project has assembled a wall-to-wall record of stand-clearing disturbance (clearcut harvest, fire) for the United States and Canada for the period 1990-...

  1. Age structure and disturbance legacy of North American forests

    Science.gov (United States)

    Y. Pan; J.M. Chen; R. Birdsey; K. McCullough; L. He; F. Deng

    2011-01-01

    Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a...

  2. Disturbance ecology and forest management: A review of the literature

    Science.gov (United States)

    Paul Rogers

    1996-01-01

    This review of the disturbance ecology literature, and how it pertains to forest management, is a resource for forest managers and researchers interested in disturbance theory, specific disturbance agents, their interactions, and appropriate methods of inquiry for specific geographic regions. Implications for the future of disturbance ecology-based management are...

  3. The interplay between climate change, forests, and disturbances

    Science.gov (United States)

    Virginia H. Dale; Linda A. Joyce; Steve McNulty; Ronald P. Neilson

    2000-01-01

    Climate change affects forests both directly and indirectly through disturbances. Disturbances are a natural and integral part of forest ecosystems, and climate change can alter these natural interactions. When disturbances exceed their natural range of variation, the change in forest structure and function may be extreme. Each disturbance affects forests differently....

  4. Automated recognition system for power quality disturbances

    Science.gov (United States)

    Abdelgalil, Tarek

    The application of deregulation policies in electric power systems has resulted in the necessity to quantify the quality of electric power. This fact highlights the need for a new monitoring strategy which is capable of tracking, detecting, classifying power quality disturbances, and then identifying the source of the disturbance. The objective of this work is to design an efficient and reliable power quality monitoring strategy that uses the advances in signal processing and pattern recognition to overcome the deficiencies that exist in power quality monitoring devices. The purposed monitoring strategy has two stages. The first stage is to detect, track, and classify any power quality violation by the use of on-line measurements. In the second stage, the source of the classified power quality disturbance must be identified. In the first stage, an adaptive linear combiner is used to detect power quality disturbances. Then, the Teager Energy Operator and Hilbert Transform are utilized for power quality event tracking. After the Fourier, Wavelet, and Walsh Transforms are employed for the feature extraction, two approaches are then exploited to classify the different power quality disturbances. The first approach depends on comparing the disturbance to be classified with a stored set of signatures for different power quality disturbances. The comparison is developed by using Hidden Markov Models and Dynamic Time Warping. The second approach depends on employing an inductive inference to generate the classification rules directly from the data. In the second stage of the new monitoring strategy, only the problem of identifying the location of the switched capacitor which initiates the transients is investigated. The Total Least Square-Estimation of Signal Parameters via Rotational Invariance Technique is adopted to estimate the amplitudes and frequencies of the various modes contained in the voltage signal measured at the facility entrance. After extracting the

  5. PID control with robust disturbance feedback control

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Vinther, Kasper; Andersen, Palle

    2015-01-01

    Disturbance Feedback Control (DFC) is a technique, originally proposed by Fuji Electric, for augmenting existing control systems with an extra feedback for attenuation of disturbances and model errors. In this work, we analyze the robustness and performance of a PID-based control system with DFC...... and performance (if such gains exist). Finally, two different simulation case studies are evaluated and compared. Our numerical studies indicate that better performance can be achieved with the proposed method compared with a conservatively tuned PID controller and comparable performance can be achieved when...... compared with an H-infinity controller....

  6. Localized plasma-density disturbance propagating along B in the interior of the ZT-40M reversed-field pinch

    International Nuclear Information System (INIS)

    Nalesso, G.; Jacobson, A.R.

    1984-01-01

    Using a ten-chord interferometer, we have measured a field-aligned (k/sub parallel/roughly-equal2 m -1 ; k/sub perpendicular/> or approx. =25 m -1 ) plasma-density disturbance propagating along B with a speed in the ion acoustic range. The propagation is purely in the electron drift direction and is observed only when the drift parameter (electron drift speed/electron thermal speed)> or approx. =0.1. A novel spatial-filter technique resolves this localized mode, which otherwise would be hidden by more robust global disturbances present along the lines of sight

  7. Prevalence of sleep disturbance in chronic pain.

    Science.gov (United States)

    Karaman, S; Karaman, T; Dogru, S; Onder, Y; Citil, R; Bulut, Y E; Tapar, H; Sahin, A; Arici, S; Kaya, Z; Suren, M

    2014-01-01

    Sleep is a vital function for human beings, which can be affected by several factors. Chronic pain is one of these factors where it is the most frequent cause for seeking medical care in combination with insomnia. The aim of this study is to examine the prevalence and relationship between sleep disturbance and chronic pain. After approval, a total of 85 Family Medicine Units from over 170 in Tokat were randomly selected using a 50% sampling. A sample of 2635 subjects, over the age of 19 years, who were registered with the selected Family Medicine Units, were assessed due to gender, age group, and the urban/rural population size of Tokat using the stratified sampling method. The sample size distribution was calculated as 1515 urban subjects, 1120 rural subjects; 1345 female subjects, 1290 male subjects; 1123 subjects between 20-39 years of age, 1103 subjects between the ages of 40-64, and 409 subjects over 64 years of age. After sampling, subjects were invited to participate in the study via an invitation letter, and agreeing individuals were taken to the Family Medicine Unit for face-to-face meetings. Written, informed consent was obtained, along with demographic data. The presence of chronic pain was recorded. According to the presence of chronic pain, all subjects were separated into two groups as Group Chronic Pain and Group Non-Chronic Pain. The visual analog scale for pain intensity, and Pittsburgh Sleep Quality Index for sleep quality, were performed with all subjects. A multiple linear regression model was used to assess the predictors of sleep quality. Analyses were conducted using the Statistical Package for Social Sciences program (SPSS Inc., Chicago, IL, USA), version 20.0. The statistical significance for all analyses was set at p 5. A moderate positive correlation was found between the global Pittsburgh Sleep Quality Index and Visual Analog Scale scores (r = 0.310, p < 0.01). A multiple linear regression analysis showed that age, gender, income, Visual

  8. Geomagnetic activity associated with Earth passage of interplanetary shock disturbances and coronal mass ejections

    International Nuclear Information System (INIS)

    Gosling, J.T.; McComas, D.J.; Phillips, J.L.; Bame, S.J.

    1991-01-01

    Previous work indicates that virtually all transient shock wave disturbances in the solar wind are driven by fast coronal mass ejection events (CMEs). Using a recently appreciated capability for distinguishing CMEs in solar wind data in the form of counterstreaming solar wind electron events, this paper explores the overall effectiveness of shock wave disturbances and CMEs in general in stimulating geomagnetic activity. The study is confined to the interval from mid-August 1978 through mid-October 1982, spanning the last solar activity maximum, when ISEE 3 was in orbit about the L1 Lagrange point 220 R e upstream from Earth. The authors find that all but one of the 37 largest geomagnetic storms in that era were associated with Earth passage of CMEs and/or shock disturbances, with the large majority of these storms being associated with interplanetary events where Earth encountered both a shock and the CME driving the shock (shock/CME events). Although CMEs and/or shock disturbances were increasingly the cause of geomagnetic activity as the level of geomagnetic activity increased, many smaller geomagnetic disturbances were unrelated to these events. Further, approximately half of all CMEs and half of all shock disturbances encountered by Earth did not produce any substantial geomagnetic activity as measured by the planetary geomagnetic index Kp. The geomagnetic effectiveness of Earth directed CMEs and shock wave disturbances was directly related to the flow speed, the magnetic field magnitude, and the strength of the southward (GSM) field component associated with the events. The initial speed of a CME close to the Sun appears to be the most crucial factor in determining if an earthward directed event will be effective in exciting a large geomagnetic disturbance

  9. Redox activity distinguishes solid-state electron transport from solution-based electron transfer in a natural and artificial protein: cytochrome C and hemin-doped human serum albumin.

    Science.gov (United States)

    Amdursky, Nadav; Ferber, Doron; Pecht, Israel; Sheves, Mordechai; Cahen, David

    2013-10-28

    Integrating proteins in molecular electronic devices requires control over their solid-state electronic transport behavior. Unlike "traditional" electron transfer (ET) measurements of proteins that involve liquid environments and a redox cycle, no redox cofactor is needed for solid-state electron transport (ETp) across the protein. Here we show the fundamental difference between these two approaches by macroscopic area measurements, which allow measuring ETp temperature dependence down to cryogenic temperatures, via cytochrome C (Cyt C), an ET protein with a heme (Fe-porphyrin) prosthetic group as a redox centre. We compare the ETp to electrochemical ET measurements, and do so also for the protein without the Fe (with metal-free porphyrin) and without porphyrin. As removing the porphyrin irreversibly alters the protein's conformation, we repeat these measurements with human serum albumin (HSA), 'doped' (by non-covalent binding) with a single hemin equivalent, i.e., these natural and artificial proteins share a common prosthetic group. ETp via Cyt C and HSA-hemin are very similar in terms of current magnitude and temperature dependence, which suggests similar ETp mechanisms via these two systems, thermally activated hopping (with ~0.1 eV activation energy) >190 K and tunneling by superexchange Fe(3+) + e(-)), measured by electrochemistry of HSA-hemin are only 4 times lower than those for Cyt C. However, while removing the Fe redox centre from the porphyrin ring markedly affects the ET rate, it hardly changes the ETp currents through these proteins, while removing the macrocycle (from HSA, which retains its conformation) significantly reduces ETp efficiency. These results show that solid-state ETp across proteins does not require the presence of a redox cofactor, and that while for ET the Fe ion is the main electron mediator, for ETp the porphyrin ring has this function.

  10. An Endogenous Electron Spin Resonance (ESR signal discriminates nevi from melanomas in human specimens: a step forward in its diagnostic application.

    Directory of Open Access Journals (Sweden)

    Eleonora Cesareo

    Full Text Available Given the specific melanin-associated paramagnetic features, the Electron Spin Resonance (ESR, called also Electron Paramagnetic Resonance, EPR analysis has been proposed as a potential tool for non-invasive melanoma diagnosis. However, studies comparing human melanoma tissues to the most appropriate physiological counterpart (nevi have not been performed, and ESR direct correlation with melanoma clinical features has never been investigated. ESR spectrum was obtained from melanoma and non-melanoma cell-cultures as well as mouse melanoma and non-melanoma tissues and an endogenous ESR signal (g = 2.005 was found in human melanoma cells and in primary melanoma tissues explanted from mice, while it was always absent in non-melanoma samples. These characteristics of the measured ESR signal strongly suggested its connection with melanin. Quantitative analyses were then performed on paraffin-embedded human melanoma and nevus sections, and validated on an independent larger validation set, for a total of 112 sections (52 melanomas, 60 nevi. The ESR signal was significantly higher in melanomas (p = 0.0002 and was significantly different between "Low Breslow's and "High Breslow's" depth melanomas (p<0.0001. A direct correlation between ESR signal and Breslow's depth, expressed in millimetres, was found (R = 0.57; p<0.0001. The eu/pheomelanin ratio was found to be significantly different in melanomas "Low Breslow's" vs melanomas "High Breslow's" depth and in nevi vs melanomas "High Breslow's depth". Finally, ROC analysis using ESR data discriminated melanomas sections from nevi sections with up to 90% accuracy and p<0.0002. In the present study we report for the first time that ESR signal in human paraffin-embedded nevi is significantly lower than signal in human melanomas suggesting that spectrum variations may be related to qualitative melanin differences specifically occurring in melanoma cells. We therefore conclude that this ESR signal

  11. Greening Electronics

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Søes Kokborg, Morten; Thomsen, Marianne

    Based on a literature review with focus on hazardous substances in waste electric and electronic equipment (WEEE) and numbers from a Danish treatment facility a flow analysis for specific substances has been conducted. Further, the accessible knowledge on human and environmental effects due...

  12. Modelling natural disturbances in forest ecosystems: a review

    OpenAIRE

    Seidl, Rupert; Fernandes, Paulo M.; Fonseca, Teresa F.; Gillet, François; Jönsson, Anna Maria; Merganičová, Katarína; Netherer, Sigrid; Arpaci, Alexander; Bontemps, Jean-Daniel; Bugmann, Harald

    2011-01-01

    Natural disturbances play a key role in ecosystem dynamics and are important factors for sustainable forest ecosystem management. Quantitative models are frequently employed to tackle the complexities associated with disturbance processes. Here we review the wide variety of approaches to modelling natural disturbances in forest ecosystems, addressing the full spectrum of disturbance modelling from single events to integrated disturbance regimes. We applied a general, process-based framework f...

  13. Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio.

    Science.gov (United States)

    Alagoz, Baris Baykant; Deniz, Furkan Nur; Keles, Cemal; Tan, Nusret

    2015-03-01

    This study investigates disturbance rejection capacity of closed loop control systems by means of reference to disturbance ratio (RDR). The RDR analysis calculates the ratio of reference signal energy to disturbance signal energy at the system output and provides a quantitative evaluation of disturbance rejection performance of control systems on the bases of communication channel limitations. Essentially, RDR provides a straightforward analytical method for the comparison and improvement of implicit disturbance rejection capacity of closed loop control systems. Theoretical analyses demonstrate us that RDR of the negative feedback closed loop control systems are determined by energy spectral density of controller transfer function. In this manner, authors derived design criteria for specifications of disturbance rejection performances of PID and fractional order PID (FOPID) controller structures. RDR spectra are calculated for investigation of frequency dependence of disturbance rejection capacity and spectral RDR analyses are carried out for PID and FOPID controllers. For the validation of theoretical results, simulation examples are presented. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Emotional Disturbance. NICHCY Disability Fact Sheet #5

    Science.gov (United States)

    National Dissemination Center for Children with Disabilities, 2010

    2010-01-01

    The mental health of our children is a natural and important concern for us all. The fact is, many mental disorders have their beginnings in childhood or adolescence, yet may go undiagnosed and untreated for years. "Umbrella" terms such as emotional disturbance, behavioral disorders, or mental illness are used to refer to mental…

  15. Solar Development on Contaminated and Disturbed Lands

    Energy Technology Data Exchange (ETDEWEB)

    Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lee, Courtney [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mosey, Gail [National Renewable Energy Lab. (NREL), Golden, CO (United States); Melius, Jenny [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-12-01

    Land classified as contaminated and disturbed across the United States has the potential to host developments of utility-scale solar power. This report examines the prospect of developing utility- and commercial-scale concentrated solar power (CSP) and solar photovoltaics (PV) technologies on degraded and environmentally contaminated lands. The potential for solar development on contaminated anddisturbed lands was assessed, and for the largest and highest solar resource sites, the economic impacts and feasibility were evaluated. Developing solar power on contaminated and disturbed lands can help create jobs and revitalize local and state economies, and selecting these sites over greenfield sites can potentially have permitting and environmental mitigation advantages. The U.S.Department of Energy (DOE) SunShot goals call for 632 GW of PV and 83 GW of CSP to be deployed by 2050. Conservative land-use estimates of this study (10 acres per megawatt) show that there are disturbed and environmentally contaminated lands throughout the country that could be suitable for utility-scale solar power, and, that there is sufficient land area to meet SunShot solar deployment goals. The purpose of this assessment is to improve the understanding of these sites and facilitate solar developers' selection of contaminated and disturbed sites for development.

  16. Visuospatial Attention Disturbance in Duchenne Muscular Dystrophy

    Science.gov (United States)

    De Moura, Maria Clara Drummond Soares; do Valle, Luiz Eduardo Ribeiro; Resende, Maria Bernadete Dutra; Pinto, Katia Osternack

    2010-01-01

    Aim: The cognitive deficits present in the Duchenne muscular dystrophy (DMD) are not yet well characterized. Attention, considered to be the brain mechanism responsible for the selection of sensory stimuli, could be disturbed in DMD, contributing, at least partially, to the observed global cognitive deficit. The aim of this study was to…

  17. Disturbing Practices: Training Workers to Be Lean

    Science.gov (United States)

    Yasukawa, Keiko; Brown, Tony; Black, Stephen

    2014-01-01

    Purpose: The purpose of this paper is to explore the possibilities for expansive learning during organisational change. It considers the introduction of "lean production" as a disturbance to the existing work practices. Design/methodology/approach: The paper considers two case studies of "lean production" training with…

  18. Types and Treatment of Pediatric Sleep Disturbances

    Science.gov (United States)

    Hamilton, Gloria J.

    2009-01-01

    This article provides an overview of pediatric sleep disturbances with emphases on types and treatments. Relationships between sleep disorders and comorbid conditions function to exacerbate and maintain both disorders. An estimated 20% of teenagers experience chronic partial sleep deprivation, resulting in problems with memory, attention, and…

  19. Time Perspective, Mood Disturbance, and Suicide Liberation.

    Science.gov (United States)

    Lennings, C. J.

    1994-01-01

    Assessed 238 university students and 159 high school students on temporal and personality measures. Found that temporal extension, temporal attitude, and impulsivity had comparatively little effect on suicide ideation after controlling effects of mood disturbance. However, negative temporal attitudes appeared to have significant impact on suicide…

  20. Body representation disturbances in anorexia nervosa

    NARCIS (Netherlands)

    Keizer, A.

    2014-01-01

    One of the main symptoms of anorexia nervosa (AN) is a disturbed experience of body size and shape. Although patients are underweight, they experience their body as bigger than it in reality is. Previous studies were mainly conducted by (clinical) psychologists and psychiatrists, and almost

  1. Combine material against electromagnetic pulse disturbance

    International Nuclear Information System (INIS)

    Liu Yan

    2004-01-01

    A novel combined material is introduced, which is hard against electromagnetic pulse disturbance, The attenuation characteristics and the penetration probability of the combine material is discussed in detail. The penetration probability of electromagnetic wave is calculated approximately and the characteristic curve is measured for this material. (authors)

  2. Unusual metaphyseal disturbance in two kittens

    International Nuclear Information System (INIS)

    Gunn-Moore, D.A.; Hagard, G.; Turner, C.; Duncan, A.W.; Barr, F.J.

    1996-01-01

    This report describes the presenting features, radiographic changes, biochemical alterations and clinical progress of two kittens, from separate litters, which were found to have a growth plate disturbance initially diagnosed and treated as vitamin D3-dependent rickets, but subsequently suspected to be a metaphyseal chondrodysplasia

  3. Effectiveness of carnosine on disturbed electrolytes homeostasis ...

    African Journals Online (AJOL)

    We aimed to assess the effect of well known antioxidant carnosine on disturbed plasma and intraerythrocytes electrolytes and Na+-K+-ATPase activity by cisplatin. 24 male albino Wistar rats were selected and divided into 4 groups: Group I = untreated control; Group II = cisplatin control (received cisplatin at a dose of 3 mg/ ...

  4. Body image disturbance and skin bleaching.

    Science.gov (United States)

    Charles, Christopher A D; McLean, Shua-Kym

    2017-11-01

    This study looks at body image disturbance among Jamaicans who bleach their skin. The hypothesis states that there is a positive relationship between skin bleaching and body image disturbance. The study used a convenience sample of 160 participants with a skin bleaching group (n = 80) and a non-bleaching comparison group (n = 80). The instrument included demographic questions, the body image disturbance questionnaire (BIDQ), and questions about skin bleaching. The results of a t-test revealed that the skin bleaching group (M = 1.5255, SD = 0.42169) was not significantly different from the non-bleaching group (M = 1.4938, SD = 0.74217) in terms of body image disturbance, t(158) = 0.333, p = .740. The participants who bleached did not suffer from body image disturbance. Self-reports revealed that they bleached to acquire beauty, attract a partner, elude the police, and market skin bleaching products. The practice was fashionable and popular and it made some participants feel good, while others were fans of a popular musical artiste who bleached his skin. The majority of participants bleached because of the perceived personal, social, and entrepreneurial benefits of the practice and not because they suffered emotional distress, anxiety, and functional impairment because of their skin colour. However, there was some level of BID among the minority of participants who argued that they bleached because they wanted to be pretty so they were emotionally distressed about there body image and experienced functional impairment. © 2017 The British Psychological Society.

  5. Discriminating Natural Variation from Legacies of Disturbance in Semi-Arid Forests, Southwestern USA

    Science.gov (United States)

    Swetnam, T. L.; Lynch, A. M.; Falk, D. A.; Yool, S. R.; Guertin, D. P.

    2014-12-01

    Characterizing differences in existing vegetation driven by natural variation versus disturbance legacies could become a critical component of applied forest management practice with important implications for monitoring ecologic succession and eco-hydrological interactions within the critical zone. Here we characterize variations in aerial LiDAR derived forest structure at individual tree scale in Arizona and New Mexico. Differences in structure result from both topographic and climatological variations and from natural and human related disturbances. We chose a priori undisturbed and disturbed sites that included preservation, development, logging and wildfire as exemplars. We compare two topographic indices, the topographic position index (TPI) and topographic wetness index (TWI), to two local indicators of spatial association (LISA): the Getis-Ord Gi and Anselin's Moran I. We found TPI and TWI correlate well to positive z-scores (tall trees in tall neighborhoods) in undisturbed areas and that disturbed areas are clearly defined by negative z-scores, in some cases better than what is visible from traditional orthophotography and existing GIS maps. These LISA methods also serve as a robust technique for creating like-clustered stands, i.e. common stands used in forest inventory monitoring. This research provides a significant advancement in the ability to (1) quantity variation in forest structure across topographically complex landscapes, (2) identify and map previously unrecorded disturbance locations, and (3) quantify the different impacts of disturbance within the perimeter of a stand or event at ecologically relevant scale.

  6. Response of Nitrogen Leaching to Nitrogen Deposition in Disturbed and Mature Forests of Southern China

    Institute of Scientific and Technical Information of China (English)

    FANG Yun-Ting; M. YOH; MO Jiang-Ming; P. GUNDERSEN; ZHOU Guo-Yi

    2009-01-01

    Current nitrogen (N) leaching losses and their responses to monthly N additions were investigated under a disturbed pine (Pinus massoniana) forest and a mature monsoon broadleaf forest in southern China. N leaching losses from both disturbed and mature forests were quite high (14.6 and 29.2 kg N ha-1 year-1, respectively), accounting for 57% and 80% of their corresponding atmospheric N inputs. N leaching losses were substantially increased following the first 1.5 years of N applications in both forests. The average increases induced by the addition of 50 and 100 kg N ha-1 year-1 were 36.5 and 24.9 kg N ha-1 year-1, respectively, in the mature forest, accounting for 73.0% and 24.9% of the annual amount of N added, and 14.2 and 16.8 kg N ha-1 year-1 in the disturbed forest, accounting for 28.4% and 16.8% of the added N. Great N leaching and a fast N leaching response to N additions in the mature forest might result from long-term N accumulation and high ambient N deposition load (greater than 30 kg N ha-1 year-1 over the past 15 years), whereas in the disturbed forest, it might result from the human disturbance and high ambient N deposition load. These results suggest that both disturbed and mature forests in the study region may be sensitive to increasing N deposition.

  7. Coral population trajectories, increased disturbance and management intervention: A sensitivity analysis

    KAUST Repository

    Riegl, Bernhard; Berumen, Michael L.; Bruckner, Andrew

    2013-01-01

    Coral reefs distant from human population were sampled in the Red Sea and one-third showed degradation by predator outbreaks (crown-of-thorns-starfish=COTS observed in all regions in all years) or bleaching (1998, 2010). Models were built to assess future trajectories. They assumed variable coral types (slow/fast growing), disturbance frequencies (5,10,20years), mortality (equal or not), and connectivity (un/connected to un/disturbed community). Known disturbances were used to parameterize models. Present and future disturbances were estimated from remote-sensing chlorophyll and temperature data. Simulations and sensitivity analysis suggest community resilience at >20-year disturbance frequency, but degradation at higher frequency. Trajectories move from fast-grower to slow-grower dominance at intermediate disturbance frequency, then again to fast-grower dominance. A similar succession was observed in the field: Acropora to Porites to Stylophora/Pocillopora dominance on shallow reefs, and a transition from large poritids to small faviids on deep reefs. Synthesis and application: Even distant reefs are impacted by global changes. COTS impacts and bleaching were key driver of coral degradation, coral population decline could be reduced if these outbreaks and bleaching susceptibility were managed by maintaining water quality and by other interventions. Just leaving reefs alone, seems no longer a satisfactory option. 2013 The Authors. Ecology and Evolution.

  8. Coral population trajectories, increased disturbance and management intervention: A sensitivity analysis

    KAUST Repository

    Riegl, Bernhard

    2013-03-07

    Coral reefs distant from human population were sampled in the Red Sea and one-third showed degradation by predator outbreaks (crown-of-thorns-starfish=COTS observed in all regions in all years) or bleaching (1998, 2010). Models were built to assess future trajectories. They assumed variable coral types (slow/fast growing), disturbance frequencies (5,10,20years), mortality (equal or not), and connectivity (un/connected to un/disturbed community). Known disturbances were used to parameterize models. Present and future disturbances were estimated from remote-sensing chlorophyll and temperature data. Simulations and sensitivity analysis suggest community resilience at >20-year disturbance frequency, but degradation at higher frequency. Trajectories move from fast-grower to slow-grower dominance at intermediate disturbance frequency, then again to fast-grower dominance. A similar succession was observed in the field: Acropora to Porites to Stylophora/Pocillopora dominance on shallow reefs, and a transition from large poritids to small faviids on deep reefs. Synthesis and application: Even distant reefs are impacted by global changes. COTS impacts and bleaching were key driver of coral degradation, coral population decline could be reduced if these outbreaks and bleaching susceptibility were managed by maintaining water quality and by other interventions. Just leaving reefs alone, seems no longer a satisfactory option. 2013 The Authors. Ecology and Evolution.

  9. Disturbed growth and selection of the human ovarian follicle

    NARCIS (Netherlands)

    T.D. Pache

    1993-01-01

    textabstractThe first objective of this stody was to review some aspects of current knowledge of ovarian function in normal menstrual cycles. A discussion of the anatomy and physiology of the normal ovary can be found in chapter 2. The second objective was to provide new information about the

  10. Disturbance and topography shape nitrogen availability and δ15 N over long-term forest succession

    Science.gov (United States)

    Perakis, Steven; Tepley, Alan J.; Compton, Jana

    2015-01-01

    Forest disturbance and long-term succession towards old-growth are thought to increase nitrogen (N) availability and N loss, which should increase soil δ15N values. We examined soil and foliar patterns in N and δ15N, and soil N mineralization, across 800 years of forest succession in a topographically complex montane landscape influenced by human logging and wildfire. In contrast to expectations, we found that disturbance caused declines in surface mineral soil δ15N values, both in logged forests measured 40–50 years after disturbance, and in unlogged forests disturbed by severe wildfire within the last 200 years. Both symbiotic N fixation and N transfers from disturbed vegetation and detritus could lower soil δ15N values after disturbance. A more important role for symbiotic N fixation is suggested by lower soil δ15N values in slow-successional sites with slow canopy closure, which favors early-successional N fixers. Soil δ15N values increased only marginally throughout 800 years of succession, reflecting soil N uptake by vegetation and strong overall N retention. Although post-disturbance N inputs lowered surface soil δ15N values, steady-state mass balance calculations suggest that wildfire combustion of vegetation and detritus can dominate long-term N loss and increase whole-ecosystem δ15N. On steeper topography, declining soil δ15N values highlight erosion and accelerated soil turnover as an additional abiotic control on N balances. We conclude for N-limited montane forests that soil δ15N and N availability are less influenced by nitrate leaching and denitrification loss than by interactions between disturbance, N fixation, and erosion.

  11. Electronic Nose and Electronic Tongue

    Science.gov (United States)

    Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

    Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.

  12. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  13. Electronic-nose applications in forensic science and for analysis of volatile biomarkers in the human breath

    Science.gov (United States)

    AD Wilson

    2014-01-01

    The application of electronic-nose (E-nose) technologies in forensic science is a recent new development following a long history of progress in the development of diverse applications in the related biomedical and pharmaceutical fields. Data from forensic analyses must satisfy the needs and requirements of both the scientific and legal communities. The type of data...

  14. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  15. How to Make "The Fourth Revolution". Human Factors in the Adoption of Electronic Instructional Aids. Memorandum Number 73/5.

    Science.gov (United States)

    Demerath, Nicholas J.; Daniels, Lois A.

    The prospects and problems associated with getting American higher education to utilize more fully electronic technologies are examined. Part I surveys the diversity of higher education and its students and concludes that technological applications will have to be correspondingly varied, despite the tendency to "massification". Part II, consisting…

  16. Study and structural and chemical characterization of human dental smalt by electron microscopy; Estudio y caracterizacion estructural y quimico del esmalte dental humano por microscopia electronica

    Energy Technology Data Exchange (ETDEWEB)

    Belio R, I A; Reyes G, J [Instituto de Fisica, UNAM, A.P. 20-364, 01000 Mexico D.F. (Mexico)

    1998-07-01

    The study of human dental smalt has been subject to investigation for this methods with electron microscopy, electron diffraction, X-ray diffraction and image simulation programs have been used with the purpose to determine its chemical and structural characteristics of the organic and inorganic materials. This work has been held mainly for the characterization of hydroxyapatite (Ca){sub 10} (PO{sub 4}){sub 6} (OH{sub 4}){sub 2}, inorganic material which conforms the dental smalt in 97%, so observing its structural unity which is composed by the prisms and these by crystals and atoms. It was subsequently initiated the study of the organic material, with is precursor of itself. (Author)

  17. The Storm Time Evolution of the Ionospheric Disturbance Plasma Drifts

    Science.gov (United States)

    Zhang, Ruilong; Liu, Libo; Le, Huijun; Chen, Yiding; Kuai, Jiawei

    2017-11-01

    In this paper, we use the C/NOFS and ROCSAT-1 satellites observations to analyze the storm time evolution of the disturbance plasma drifts in a 24 h local time scale during three magnetic storms driven by long-lasting southward IMF Bz. The disturbance plasma drifts during the three storms present some common features in the periods dominated by the disturbance dynamo. The newly formed disturbance plasma drifts are upward and westward at night, and downward and eastward during daytime. Further, the disturbance plasma drifts are gradually evolved to present significant local time shifts. The westward disturbance plasma drifts gradually migrate from nightside to dayside. Meanwhile, the dayside downward disturbance plasma drifts become enhanced and shift to later local time. The local time shifts in disturbance plasma drifts are suggested to be mainly attributed to the evolution of the disturbance winds. The strong disturbance winds arisen around midnight can constantly corotate to later local time. At dayside the westward and equatorward disturbance winds can drive the F region dynamo to produce the poleward and westward polarization electric fields (or the westward and downward disturbance drifts). The present results indicate that the disturbance winds corotated to later local time can affect the local time features of the disturbance dynamo electric field.

  18. Interaction of historical and nonhistorical disturbances maintains native plant communities.

    Science.gov (United States)

    Davies, K W; Svejcar, T J; Bates, J D

    2009-09-01

    Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.

  19. Immediate response of meio and macrobenthos to disturbance caused by a benthic disturber

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Ansari, Z.A.; Matondkar, S.G.P.; Rodrigues, N.

    The probable impact of nodule mining on benthic biota was studied by creating a benthic disturbance. During the predisturbance study in the Central Indian Basin, box core samples were analyzed for the distribution, composition and abundance...

  20. Ecological Catastrophes and Disturbance Relicts: A Case Study from Easter Island

    Science.gov (United States)

    Wynne, J.

    2014-12-01

    Caves are often considered buffered environments in terms of their ability to sustain near constant microclimatic conditions. However, environments within cave entrances are expected to respond most quickly to changing surface conditions. We cataloged a relict assemblage of at least 10 endemic arthropods likely restricted to caves and occurring primarily within cave entranceways. Of these animals, eight were considered new undescribed species. These endemic arthropods have persisted in Rapa Nui (Easter Island) caves despite a catastrophic ecological shift induced by island-wide deforestation, fire intolerance, and drought, as well as intensive livestock grazing and surface ecosystems dominated by invasive species. We consider these animals to be "disturbance relicts" - species whose distributions are now limited to areas that experienced minimal human disturbance historically. Today, these species represent one-third of the Rapa Nui's known endemic arthropods. Given the island's severely depauperate native fauna, these arthropods should be considered among the highest priority targets for biological conservation. In other regions globally, epigean examples of imperiled disturbance relicts persisting within narrow distributional ranges have been documented. As human activity intensifies, and habitat loss and fragmentation continues worldwide, additional disturbance relicts will be identified. We expect extinction debts, global climate change and interactions with invasive species will challenge the persistence of both hypogean and epigean disturbance relict species.

  1. Gastroesophageal reflux disease and vocal disturbances

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Coelho de Arruda Henry

    2011-06-01

    Full Text Available CONTEXT: Gastroesophageal reflux disease is a chronic disease in which gastroduodenal contents reflux into the esophagus. The clinical picture of gastroesophageal reflux disease is usually composed by heartburn and regurgitation (typical manifestations. Atypical manifestations (vocal disturbances and asthma may also be complaint. OBJECTIVE: To analyse the clinical, endoscopic, manometric and pHmetric aspects of patients suffering from gastroesophageal reflux disease associated with vocal disturbances. METHODS: Fifty patients with gastroesophageal reflux disease were studied, including 25 with vocal disturbances (group 1 - G1 and 25 without these symptoms (group 2 - G2. All patients were submitted to endoscopy, manometry and esophageal pHmetry (2 probes. The group 1 patients were submitted to videolaryngoscopy. RESULTS: Endoscopic findings: non-erosive reflux disease was observed in 95% of G1 patients and 88% of G2. Videolaryngoscopy: vocal fold congestion, asymmetry, nodules and polyps were observed in G1 patients. Manometric findings: pressure in the lower esophageal sphincter (mm Hg: 11.6 ± 5.2 in G1 and 14.0 ± 6.2 in G2 (P = 0.14; pressure in the upper esophageal sphincter (mm Hg: 58.4 ± 15.9 in G1 and 69.5 ± 30.7 in the controls. pHmetric findings: De Meester index: 34.0 ± 20.9 in G1 and 15.4 ± 9.4 in G2 (P<0.001; number of reflux episodes in distal probe: 43.0 ± 20.4 in G1 and 26.4 ± 17.2 in G2 (P = 0.003; percentage of time with esophageal pH value lower than 4 units (distal sensor: 9.0% ± 6.4% in G1 and 3.4% ± 2.1% in G2 (P<0.001; number of reflux episodes in proximal probe: 7.5 ± 10.9 in G1 and 5.3 ± 5.7 in G2 (P = 0.38; percentage of time with esophageal pH values lower than 4 units (Proximal probe: 1.2 ± 2.7 in G1 and 0.5 ± 0.7 in G2 (P = 0.21. CONCLUSIONS: 1 The clinical, endoscopic, and manometric findings observed in patients with vocal disturbance do not differ from those without these symptoms; 2 gastroesophageal

  2. Latitudinal profile of the ionospheric disturbance dynamo magnetic signature: comparison with the DP2 magnetic disturbance

    Directory of Open Access Journals (Sweden)

    K. Z. Zaka

    2009-09-01

    Full Text Available During magnetic storms, the auroral electrojets intensification affects the thermospheric circulation on a global scale. This process which leads to electric field and current disturbance at middle and low latitudes, on the quiet day after the end of a storm, has been attributed to the ionospheric disturbance dynamo (Ddyn. The magnetic field disturbance observed as a result of this process is the reduction of the H component amplitude in the equatorial region which constitutes the main characteristic of the ionospheric disturbance dynamo process, associated with a westward electric current flow. The latitudinal profile of the Ddyn disturbance dynamo magnetic signature exhibits an eastward current at mid latitudes and a westward one at low latitudes with a substantial amplification at the magnetic equator. Such current flow reveals an "anti-Sq" system established between the mid latitudes and the equatorial region and opposes the normal Sq current vortex. However, the localization of the eastward current and consequently the position and the extent of the "anti-Sq" current vortex changes from one storm to another. Indeed, for a strong magnetic storm, the eastward current is well established at mid latitudes about 45° N and for a weak magnetic storm, the eastward current is established toward the high latitudes (about 60° N, near the Joule heating region, resulting in a large "anti-Sq" current cell. The latitudinal profile of the Ddyn disturbance as well as the magnetic disturbance DP2 generated by the mechanism of prompt penetration of the magnetospheric convection electric field in general, show a weak disturbance at the low latitudes with a substantial amplification at the magnetic equator. Due to the intensity of the storm, the magnitude of the DP2 appears higher than the Ddyn over the American and Asian sector contrary to the African sector.

  3. Disturbance and topography shape nitrogen availability and δ15N over long-term forest succession

    Science.gov (United States)

    Forest disturbance and long-term succession can promote open N cycling that increases N loss and soil δ15N values. We examined soil and foliar patterns in N and δ15N, and soil N mineralization, across a topographically complex montane forest landscape influenced by human logging ...

  4. Implications of interacting microscale habitat heterogeneity and disturbance events on Folsomia candida (Collembola) population dynamics

    DEFF Research Database (Denmark)

    Meli, Mattia; Palmqvist, Annemette; Forbes, Valery E

    2014-01-01

    human activities that may cause habitat destruction, we focused on agricultural practices. Soil organisms living in a cultivated field are subjected to habitat loss and fragmentation as well as disturbance events generated by the application of agrochemicals and related activities. In addition...

  5. Impact of Market-Based Disturbance on the Composition of West Virginia's Forest Resource

    Science.gov (United States)

    William G. Luppold; John E. Baumgras; John E. Baumgras

    2000-01-01

    The eastern hardwood resource has been shaped by a combination of human and natural disturbances. This impact on the forest resources of West Virginia has been especially dramatic. This resource has changed from a virgin forest dominated white oak, chestnut, spruce, white pine, and hemlock in the late 19th century, to one dominated by red oak in the 1950's, to...

  6. Restoring Diversity after Cattail Expansion: Disturbance, Resilience, and Seasonality in a Tropical Dry Wetland.

    Science.gov (United States)

    As the human footprint expands, ecologists and resource managers are increasingly challenged to explain and/or manage abrupt ecosystem transformations (i.e., regime shifts) that have produced novel ecosystems. In this study, we investigate the role of a mechanical disturbance tha...

  7. Scanning electron microscopy (SEM) and X-ray dispersive spectrometry evaluation of direct laser metal sintering surface and human bone interface: a case series.

    Science.gov (United States)

    Mangano, Carlo; Piattelli, Adriano; Raspanti, Mario; Mangano, Francesco; Cassoni, Alessandra; Iezzi, Giovanna; Shibli, Jamil Awad

    2011-01-01

    Recent studies have shown that direct laser metal sintering (DLMS) produces structures with complex geometry and consequently that allow better osteoconductive properties. The aim of this patient report was to evaluate the early bone response to DLMS implant surface retrieved from human jaws. Four experimental DLMS implants were inserted in the posterior mandible of four patients during conventional dental implant surgery. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for scanning electron microscopy (SEM) and histomorphometric analysis to evaluate the bone-implant interface. The SEM and EDX evaluations showed a newly formed tissue composed of calcium and phosphorus. The bone-to-implant contact presented a mean of 60.5 ± 11.6%. Within the limits of this patient report, data suggest that the DLMS surfaces presented a close contact with the human bone after a healing period of 8 weeks.

  8. A walk on the wild side: Disturbance dynamics and the conservation and management of European mountain forest ecosystems.

    Science.gov (United States)

    Kulakowski, Dominik; Seidl, Rupert; Holeksa, Jan; Kuuluvainen, Timo; Nagel, Thomas A; Panayotov, Momchil; Svoboda, Miroslav; Thorn, Simon; Vacchiano, Giorgio; Whitlock, Cathy; Wohlgemuth, Thomas; Bebi, Peter

    2017-03-15

    Mountain forests are among the most important ecosystems in Europe as they support numerous ecological, hydrological, climatic, social, and economic functions. They are unique relatively natural ecosystems consisting of long-lived species in an otherwise densely populated human landscape. Despite this, centuries of intensive forest management in many of these forests have eclipsed evidence of natural processes, especially the role of disturbances in long-term forest dynamics. Recent trends of land abandonment and establishment of protected forests have coincided with a growing interest in managing forests in more natural states. At the same time, the importance of past disturbances highlighted in an emerging body of literature, and recent increasing disturbances due to climate change are challenging long-held views of dynamics in these ecosystems. Here, we synthesize aspects of this Special Issue on the ecology of mountain forest ecosystems in Europe in the context of broader discussions in the field, to present a new perspective on these ecosystems and their natural disturbance regimes. Most mountain forests in Europe, for which long-term data are available, show a strong and long-term effect of not only human land use but also of natural disturbances that vary by orders of magnitude in size and frequency. Although these disturbances may kill many trees, the forests themselves have not been threatened. The relative importance of natural disturbances, land use, and climate change for ecosystem dynamics varies across space and time. Across the continent, changing climate and land use are altering forest cover, forest structure, tree demography, and natural disturbances, including fires, insect outbreaks, avalanches, and wind disturbances. Projected continued increases in forest area and biomass along with continued warming are likely to further promote forest disturbances. Episodic disturbances may foster ecosystem adaptation to the effects of ongoing and future

  9. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  10. Reaction Wheel Disturbance Model Extraction Software - RWDMES

    Science.gov (United States)

    Blaurock, Carl

    2009-01-01

    The RWDMES is a tool for modeling the disturbances imparted on spacecraft by spinning reaction wheels. Reaction wheels are usually the largest disturbance source on a precision pointing spacecraft, and can be the dominating source of pointing error. Accurate knowledge of the disturbance environment is critical to accurate prediction of the pointing performance. In the past, it has been difficult to extract an accurate wheel disturbance model since the forcing mechanisms are difficult to model physically, and the forcing amplitudes are filtered by the dynamics of the reaction wheel. RWDMES captures the wheel-induced disturbances using a hybrid physical/empirical model that is extracted directly from measured forcing data. The empirical models capture the tonal forces that occur at harmonics of the spin rate, and the broadband forces that arise from random effects. The empirical forcing functions are filtered by a physical model of the wheel structure that includes spin-rate-dependent moments (gyroscopic terms). The resulting hybrid model creates a highly accurate prediction of wheel-induced forces. It accounts for variation in disturbance frequency, as well as the shifts in structural amplification by the whirl modes, as the spin rate changes. This software provides a point-and-click environment for producing accurate models with minimal user effort. Where conventional approaches may take weeks to produce a model of variable quality, RWDMES can create a demonstrably high accuracy model in two hours. The software consists of a graphical user interface (GUI) that enables the user to specify all analysis parameters, to evaluate analysis results and to iteratively refine the model. Underlying algorithms automatically extract disturbance harmonics, initialize and tune harmonic models, and initialize and tune broadband noise models. The component steps are described in the RWDMES user s guide and include: converting time domain data to waterfall PSDs (power spectral

  11. Associations of sleep disturbance with ADHD

    DEFF Research Database (Denmark)

    Hvolby, A.

    2015-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is commonly associated with disordered or disturbed sleep. The relationships of ADHD with sleep problems, psychiatric comorbidities and medications are complex and multidirectional. Evidence from published studies comparing sleep in individuals......, difficulty with morning awakenings, sleep onset difficulties, sleep-disordered breathing, night awakenings and daytime sleepiness in subjective studies. ADHD is also frequently coincident with sleep disorders (obstructive sleep apnea, peripheral limb movement disorder, restless legs syndrome and circadian......-rhythm sleep disorders). Psychostimulant medications are associated with disrupted or disturbed sleep, but also 'paradoxically' calm some patients with ADHD for sleep by alleviating their symptoms. Long-acting formulations may have insufficient duration of action, leading to symptom rebound at bedtime. Current...

  12. An artificial intelligence approach towards disturbance analysis

    International Nuclear Information System (INIS)

    Fiedler, U.; Lindner, A.; Baldeweg, F.; Klebau, J.

    1986-01-01

    Scale and degree of sophistication of technological plants, e.g. nuclear power plants, have been essentially increased during the last decades. Conventional disturbance analysis systems have proved to work successfully in well-known situations. But in cases of emergencies, the operator needs more advanced assistance in realizing diagnosis and therapy control. The significance of introducing artificial intelligence (AI) methods in nuclear power technology is emphasized. Main features of the on-line disturbance analysis system SAAP-2 are reported about. It is being developed for application to nuclear power plants. Problems related to man-machine communication will be gone into more detail, because their solution will influence end-user acceptance considerably. (author)

  13. Parkinson's Disease and Sleep/Wake Disturbances

    Directory of Open Access Journals (Sweden)

    Todd J. Swick

    2012-01-01

    Full Text Available Parkinson's disease (PD has traditionally been characterized by its cardinal motor symptoms of bradykinesia, rigidity, resting tremor, and postural instability. However, PD is increasingly being recognized as a multidimensional disease associated with myriad nonmotor symptoms including autonomic dysfunction, mood disorders, cognitive impairment, pain, gastrointestinal disturbance, impaired olfaction, psychosis, and sleep disorders. Sleep disturbances, which include sleep fragmentation, daytime somnolence, sleep-disordered breathing, restless legs syndrome (RLS, nightmares, and rapid eye movement (REM sleep behavior disorder (RBD, are estimated to occur in 60% to 98% of patients with PD. For years nonmotor symptoms received little attention from clinicians and researchers, but now these symptoms are known to be significant predictors of morbidity in determining quality of life, costs of disease, and rates of institutionalization. A discussion of the clinical aspects, pathophysiology, evaluation techniques, and treatment options for the sleep disorders that are encountered with PD is presented.

  14. Memory and learning disturbances in multiple sclerosis

    International Nuclear Information System (INIS)

    Izquierdo, Guillermo; Mir, Jordi; Gonzalez, Manuel; Martinez-Parra, Carlos; Campoy, Francisco Jr

    1991-01-01

    Thirty-five patients with definite multiple sclerosis (MS) were studied. They underwent neuropsychological testing and magnetic resonance imaging (MRI). The MRI findings at different brain areas levels were compared with the neuropsychological findings. A quantitative system was used to measure MRI-MS lesions. In this series, a positive correlation was established between memory and learning disturbances measured by Battery 144, and the lesions measured by MRI (total, hemispheric and , particularly, periventricular lesions). MRI can detect MS lesions, and this study shows that a correlation between MRI and neuropsychological findings is possible if quantitative methods are used to distinguish different MS involvement areas in relation to neuropsychological tasks. These findings suggest that hemispheric lesions in MS produce cognitive disturbances and MRI could be a useful tool in predicting memory and learning impairment. (author). 20 refs.; 1 fig.; 2 tabs

  15. [Alienation: Differential Psychopathology of Ego-Disturbances].

    Science.gov (United States)

    Bodatsch, M; Kuhn, J

    2016-11-01

    Alienation, i. e. disorders of the inner experience of integrity, continuity, and agency, represents a feature of both psychotic and non-psychotic disorders. Thereby, ego disturbances are thought to be specific for schizophrenia. Depersonalisation, in contrast, has been reported in schizophrenia as well as a neurotic, probably distinct syndrome. The differentiation of psychotic vs. non-psychotic alienation is often all but trivial. The present paper provides an overview of the historical roots and the psychopathological conceptualizations of alienation. Clinically relevant features of psychotic alienation are highlighted. Experience of passivity, loss of authenticity and disturbances of striving and volition appear as psychotic characteristics. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Update on endocrine disturbances in anorexia nervosa

    DEFF Research Database (Denmark)

    Støving, R K; Hangaard, J; Hagen, C

    2001-01-01

    The marked endocrine changes that occur in anorexia nervosa have aroused a great deal of interest, and over the last decade much research has been conducted in this field. The endocrine disturbances are not specific to this disorder, as they also occur in starvation states secondary to other causes...... of the large body of literature concerning endocrine aspects of anorexia nervosa with the main focus on the latest results, which provide leads for potential etiological theories....

  17. Sleep disturbances in myotonic dystrophy type 2

    OpenAIRE

    Shepard, Paul; Lam, Erek M.; St. Louis, Erik K.; Dominik, Jacob

    2012-01-01

    Sleep disorders in myotonic dystrophy type 1 (DM1) are common and include sleep disordered breathing (SDB), hypersomnia, and fatigue. Little is known regarding the occurrence of sleep disturbance in myotonic dystrophy type 2 (DM2). We hypothesized that DM2 patients may frequently harbor sleep disorders. We reviewed medical records of all genetically confirmed cases of DM2 seen at our sleep center between 1997 and 2010 for demographic, laboratory, overnight oximetry, and polysomnography (PSG) ...

  18. Interceptive management of eruption disturbances: case report.

    Science.gov (United States)

    Cozza, Paola; Marino, Alessandra; Lagana, Giuseppina

    2004-01-01

    The aim of the present report is to describe a case of a patient with eruption disturbances of an ankylosed lower primary second molar, delayed development of a maxillary permanent canine associated with an odontoma and a class III dental malocclusion. In such a case the objectives of treatment are: to prevent impaction of the lower second premolar and tipping of the lower first molar; to establish correct anterior overbite and overjet and to control the development of the permanent upper canine.

  19. Sleep disturbances in restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Jović Jasmina

    2018-01-01

    Full Text Available Background/Aim. Resteless legs syndrome (RLS is chronical neurological disorder characterized by urge to move legs that is usually accompanied by unpleasant sensations in the lower extremities. Sleep disturbance is one of the main accompanying symptoms of RLS which exists in approximatelly 90% of patients. Impairment of sleep is related to daily sleepiness, depressive and anxiety disorders. The aim of this study was to detect frequency and characterisitics of sleep-related symptoms in patients with RLS, and its impairrment to daily sleepiness, fatique, anxiety and depression. Methods. We have examinated 94 patients with RLS. The diagnose of RLS was based on questionnaire with 4 specific questions according to the International Restless Legs Syndrome Study Group (IRLSSG criteria updated in 2003. Severity of symptoms was astimated with IRLSSG Rating Scale, depression and anxiety with Hamilton Depression Rating Scale (HDRS and Hamilton Anxiety Rating Scale (HARS and sleepiness with Epworth Sleepiness scale (ESS. We astimated sleep characteristics and disturbances with specific questionnaire. Results. In our study 79.9% of patients had sleep-related symptoms. Average sleep duration was 6.50 ± 1.42 hours, with average frequency of awakening 2.34 ± 1.69 times per night. Average ESS score was 5.12 ± 4.08 (0–17. Patients with more severe symptoms had higher degree of sleepiness (p = 0.005. Patients with higher symptoms frequency, significantly more often had sleep disturbance (p = 0.016, tiredness and daily sleepiness (p = 0.001. Daily sleepiness (ESS also significantly correlates with depression (p < 0.05 and anxiety (p = 0.012. Conclusion. Our results confirm that sleep disturbances are one of the key accompanying symptoms of RLS which cause daily sleepiness, tiredness, depression and anxiety. Therefore, their early recognition and appropriate treatment must be a priority in RLS patients.

  20. Earthworms – good indicators for forest disturbance

    OpenAIRE

    YAHYA KOOCH; KATAYOUN HAGHVERDI

    2014-01-01

    In temperate forests, formation of canopy gaps by windthrow is a characteristic natural disturbance event. Little work has been done on the effects of canopy gaps on soil properties and fauna, especially earthworms as ecosystem engineers. We conducted a study to examine the reaction of earthworms (density/biomass) and different soil properties (i.e., soil moisture, pH, organic matter, total N, and available Ca) to different canopy gap areas in 25-ha areas of Liresar district beech forest loca...

  1. Perceptions of natural disturbance in Tatra National Park, Poland

    Directory of Open Access Journals (Sweden)

    Švajda Juraj

    2016-06-01

    Full Text Available Since the last decades, natural disturbances in forests including protected areas have intensified. They have the potential to impact visual quality and safety of visitors as well as spread beyond protected area boundaries. While economic and ecological impacts are well studied, there is still a lack of work focused on human dimensions and social aspects. This study examines visitor perceptions towards bark beetle infestation in Tatra National Park, Poland. The findings, based on visitor surveys collected during the summer of 2014, indicate the significance of different factors influencing visitor attitudes towards the bark beetle. Age of visitors and importance of the bark beetle issue for them (based on subjective ratings of importance of bark beetle issue for respondents are the most prominent variables. Also place of origin and environmental worldview were recognized as significantly important variables in accordance with similar studies. Results suggest management implications for park authorities including public relations and environmental education in order to increase knowledge and support for natural disturbance and ecological integrity policies in the national park.

  2. Conservation of wildlife populations: factoring in incremental disturbance.

    Science.gov (United States)

    Stewart, Abbie; Komers, Petr E

    2017-06-01

    Progressive anthropogenic disturbance can alter ecosystem organization potentially causing shifts from one stable state to another. This potential for ecosystem shifts must be considered when establishing targets and objectives for conservation. We ask whether a predator-prey system response to incremental anthropogenic disturbance might shift along a disturbance gradient and, if it does, whether any disturbance thresholds are evident for this system. Development of linear corridors in forested areas increases wolf predation effectiveness, while high density of development provides a safe-haven for their prey. If wolves limit moose population growth, then wolves and moose should respond inversely to land cover disturbance. Using general linear model analysis, we test how the rate of change in moose ( Alces alces ) density and wolf ( Canis lupus ) harvest density are influenced by the rate of change in land cover and proportion of land cover disturbed within a 300,000 km 2 area in the boreal forest of Alberta, Canada. Using logistic regression, we test how the direction of change in moose density is influenced by measures of land cover change. In response to incremental land cover disturbance, moose declines occurred where 43% of land cover was disturbed and wolf density declined. Wolves and moose appeared to respond inversely to incremental disturbance with the balance between moose decline and wolf increase shifting at about 43% of land cover disturbed. Conservation decisions require quantification of disturbance rates and their relationships to predator-prey systems because ecosystem responses to anthropogenic disturbance shift across disturbance gradients.

  3. Sleep disturbances in myotonic dystrophy type 2.

    Science.gov (United States)

    Shepard, Paul; Lam, Erek M; St Louis, Erik K; Dominik, Jacob

    2012-01-01

    Sleep disorders in myotonic dystrophy type 1 (DM1) are common and include sleep-disordered breathing, hypersomnia, and fatigue. Little is known regarding the occurrence of sleep disturbance in myotonic dystrophy type 2 (DM2). We hypothesized that DM2 patients may frequently harbor sleep disorders. We reviewed medical records of all genetically confirmed cases of DM2 seen at our sleep center between 1997 and 2010 for demographic, laboratory, overnight oximetry, and polysomnography (PSG) data. Eight patients (5 women, 3 men) with DM2 were identified. Excessive daytime sleepiness was seen in 6 patients (75%), insomnia in 5 (62.5%), and excessive fatigue in 4 (50%). Obstructive sleep apnea was diagnosed in 3 of 5 patients (60%) studied with PSG. Respiratory muscle weakness was present in all 6 patients (100%) who received pulmonary function testing. Four of 8 (50%) met criteria for diagnosis of restless legs syndrome. The clinical spectrum of DM2 may include a wide range of sleep disturbances. Although respiratory muscle weakness was frequent, sustained sleep-related hypoxia suggestive of hypoventilation was not seen in our patients. Further prospective studies are needed to examine the frequency and scope of sleep disturbances in DM2. Copyright © 2012 S. Karger AG, Basel.

  4. Sleep disturbance in older ICU patients

    Directory of Open Access Journals (Sweden)

    Sterniczuk R

    2014-06-01

    Full Text Available Roxanne Sterniczuk,1–3 Benjamin Rusak,1,2 Kenneth Rockwood31Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, 2Department of Psychiatry, Dalhousie University, Queen Elizabeth II Health Sciences Centre, Halifax, NS, 3Division of Geriatric Medicine, Department of Medicine, Queen Elizabeth II Health Sciences Centre, Halifax, NS, CanadaAbstract: Maintaining a stable and adequate sleeping pattern is associated with good health and disease prevention. As a restorative process, sleep is important for supporting immune function and aiding the body in healing and recovery. Aging is associated with characteristic changes to sleep quantity and quality, which make it more difficult to adjust sleep–wake rhythms to changing environmental conditions. Sleep disturbance and abnormal sleep–wake cycles are commonly reported in seriously ill older patients in the intensive care unit (ICU. A combination of intrinsic and extrinsic factors appears to contribute to these disruptions. Little is known regarding the effect that sleep disturbance has on health status in the oldest of old (80+, a group, who with diminishing physiological reserve and increasing prevalence of frailty, is at a greater risk of adverse health outcomes, such as cognitive decline and mortality. Here we review how sleep is altered in the ICU, with particular attention to older patients, especially those aged ≥80 years. Further work is required to understand what impact sleep disturbance has on frailty levels and poor outcomes in older critically ill patients.Keywords: intensive care unit, sleep–wake rhythm, aging, frailty

  5. Wetland restoration, flood pulsing, and disturbance dynamics

    Science.gov (United States)

    Middleton, Beth A.

    1999-01-01

    While it is generally accepted that flood pulsing and disturbance dynamics are critical to wetland viability, there is as yet no consensus among those responsible for wetland restoration about how best to plan for those phenomena or even whether it is really necessary to do so at all. In this groundbreaking book, Dr. Beth Middleton draws upon the latest research from around the world to build a strong case for making flood pulsing and disturbance dynamics integral to the wetland restoration planning process.While the initial chapters of the book are devoted to laying the conceptual foundations, most of the coverage is concerned with demonstrating the practical implications for wetland restoration and management of the latest ecological theory and research. It includes a fascinating case history section in which Dr. Middleton explores the restoration models used in five major North American, European, Australian, African, and Asian wetland projects, and analyzes their relative success from the perspective of flood pulsing and disturbance dynamics planning.Wetland Restoration also features a wealth of practical information useful to all those involved in wetland restoration and management, including: * A compendium of water level tolerances, seed germination, seedling recruitment, adult survival rates, and other key traits of wetland plant species * A bibliography of 1,200 articles and monographs covering all aspects of wetland restoration * A comprehensive directory of wetland restoration ftp sites worldwide * An extensive glossary of essential terms

  6. Earthworms – good indicators for forest disturbance

    Directory of Open Access Journals (Sweden)

    YAHYA KOOCH

    2014-08-01

    Full Text Available In temperate forests, formation of canopy gaps by windthrow is a characteristic natural disturbance event. Little work has been done on the effects of canopy gaps on soil properties and fauna, especially earthworms as ecosystem engineers. We conducted a study to examine the reaction of earthworms (density/biomass and different soil properties (i.e., soil moisture, pH, organic matter, total N, and available Ca to different canopy gap areas in 25-ha areas of Liresar district beech forest located in a temperate forest of Mazandaran province in the north of Iran. Soil samples were taken at 0-15, 15-30 and 30-45 cm depths from gap center, gap edge and closed canopy using core soil sampler with 81 cm2 cross section. The earthworms were collected simultaneously with the soil sampling by hand sorting method. Our study supports that the canopy gap will create a mosaic of environmental conditions. Earthworm's density and biomass tended to be higher in small canopy gaps compared with the other canopy gap areas. Earthworm's population showed decreasing trend from closed canopy to disturbed sites (gap edge and gap center. The top soil was more appropriate to presence of earthworms although ecological groups have occupied different soil layers. As a conclusion, earthworms can be introduced as good bio-indicator of environmental changes that occur by disturbance.

  7. Ionospheric disturbances induced by a missile launched from North Korea on 12 December 2012

    Science.gov (United States)

    Kakinami, Yoshihiro; Yamamoto, Masayuki; Chen, Chia-Hung; Watanabe, Shigeto; Lin, Charles; Liu, Jenn-Yanq; Habu, Hiroto

    2013-08-01

    disturbances caused by a missile launched from North Korea on 12 December 2012 were investigated by using the GPS total electron content (TEC). The spatial characteristic of the front edge of V-shaped disturbances produced by missiles and rockets was first determined. Considering the launch direction and the height of estimated ionospheric points at which GPS radio signal pierces the ionosphere, the missile passed through the ionosphere at heights of 391, 425, and 435 km at 0056:30, 0057:00, and 0057:30 UT, respectively. The observed velocities of the missile were 2.8 and 3.2 km/s at that time, which was estimated from the traveling speed of the front edge of V-shaped disturbances. Westward and eastward V-shaped disturbances propagated at 1.8-2.6 km/s. The phase velocities of the westward and eastward V-shaped disturbances were much faster than the speed of acoustic waves reported in previous studies, suggesting that sources other than acoustic waves may have played an important role. Furthermore, the plasma density depletion that is often observed following missile and rocket launches was not found. This suggests that the depletion resulting from the missile's exhaust was not strong enough to be observed in the TEC distribution in the topside ionosphere.

  8. Polysomnographic sleep disturbances in nicotine, caffeine, alcohol, cocaine, opioid, and cannabis use: A focused review.

    Science.gov (United States)

    Garcia, Alexandra N; Salloum, Ihsan M

    2015-10-01

    In the United States, approximately 60 million Americans suffer from sleep disorders and about 22 million Americans report substance dependence or use disorders annually. Sleep disturbances are common consequences of substance use disorders and are likely found in primary care as well as in specialty practices. The aim of this review was to evaluate the effects of the most frequently used substances-nicotine, alcohol, opioids, cocaine, caffeine, and cannabis-have on sleep parameters measured by polysomnography (PSG) and related clinical manifestations. We used electronic databases such as PubMED and PsycINFO to search for relevant articles. We only included studies that assessed sleep disturbances using polysomnography and reviewed the effects of these substances on six clinically relevant sleep parameters: Total sleep time, sleep onset latency, rapid-eye movement, REM latency, wake after sleep onset, and slow wave sleep. Our review indicates that these substances have significant impact on sleep and that their effects differ during intoxication, withdrawal, and chronic use. Many of the substance-induced sleep disturbances overlap with those encountered in sleep disorders, medical, and psychiatric conditions. Sleep difficulties also increase the likelihood of substance use disorder relapse, further emphasizing the need for optimizing treatment interventions in these patients. Our review highlights the importance of systematically screening for substance use in patients with sleep disturbances and highlights the need for further research to understand mechanisms underlying substances-induced sleep disturbances and on effective interventions addressing these conditions. © American Academy of Addiction Psychiatry.

  9. Impacts of human recreation on carnivores in protected areas.

    Science.gov (United States)

    Baker, Angela Darnell; Leberg, Paul L

    2018-01-01

    Mammalian carnivores can be particularly sensitive to human disturbance, even within protected areas (PAs). Our objective was to understand how human disturbance affects carnivore communities in southern Arizona, USA by studying habitat occupancy based on data collected using non-invasive methods in three PAs with different levels of human disturbance. Carnivore occupancy varied based on human disturbance variables (i.e., roads, trails, etc.). Common carnivore species (coyotes, gray foxes, and bobcats) had high occupancy probability in highly disturbed sites, while all other carnivore species had a higher probability of occupancy in low disturbance protected areas. Additionally, overall carnivore diversity was higher in PAs with low human disturbance. Edges of PAs appeared to negatively impact occupancy of nearly all carnivore species. We also found the presence of roads and trails, and not necessarily how much they are used, had a significant negative impact on the occupancy of most carnivore species. Furthermore, the overall level of disturbance within a PA influenced how sensitive carnivores were to human disturbance variables. Carnivores were more sensitive in PAs with higher levels of disturbance and were relatively unaffected by disturbance variables in a PA with low base levels of disturbance. Increased visitation to PAs, expected with the region's high level of population growth, is likely to cause shifts in the carnivore communities favoring species that are less sensitive to disturbance.

  10. First ultrastructural data on the human tapeworm Taenia asiatica eggs by scanning and transmission electron microscopy (SEM, TEM).

    Science.gov (United States)

    Galán-Puchades, M Teresa; Yang, Yichao; Marcilla, Antonio; Choe, Seongjun; Park, Hansol; Osuna, Antonio; Eom, Keeseon S

    2016-09-01

    Humans are definitive hosts of three species of the Taenia genus, namely Taenia solium, Taenia saginata and Taenia asiatica. The relative novelty of the latter explains the lack of knowledge concerning certain relevant aspects related to this parasite, such as its definite geographical distribution and whether its eggs can infect humans or not. So far, only the eggs of T. solium are known to be infective for humans, producing cysticercosis. Although eggs contain the infective stage, the oncosphere, there is a lack of research on the ultrastructure of eggs of human taeniids. We show, for the first time, the ultrastructure of eggs of T. asiatica by means of SEM and TEM analyses. We detected all the envelopes, namely the egg shell, vitelline layer, outer embryophoric membrane, embryophore, granular layer, basal membrane, oncospheral membrane and oncospheral tegument. Hooks surrounded by myofibrils and glycogen-like particles, the two types of secretory granules of the penetration glands, as well as several nuclei and mitochondria were also revealed in the oncospheres. In addition to the already known structures in eggs from other Taenia species, the presence of two types of small vesicles is described herein, possibly corresponding to exosomes and ectosomes because of their shape and size, which could participate in the host/parasite intercellular communication.

  11. Screen-Printed Washable Electronic Textiles as Self-Powered Touch/Gesture Tribo-Sensors for Intelligent Human-Machine Interaction.

    Science.gov (United States)

    Cao, Ran; Pu, Xianjie; Du, Xinyu; Yang, Wei; Wang, Jiaona; Guo, Hengyu; Zhao, Shuyu; Yuan, Zuqing; Zhang, Chi; Li, Congju; Wang, Zhong Lin

    2018-05-22

    Multifunctional electronic textiles (E-textiles) with embedded electric circuits hold great application prospects for future wearable electronics. However, most E-textiles still have critical challenges, including air permeability, satisfactory washability, and mass fabrication. In this work, we fabricate a washable E-textile that addresses all of the concerns and shows its application as a self-powered triboelectric gesture textile for intelligent human-machine interfacing. Utilizing conductive carbon nanotubes (CNTs) and screen-printing technology, this kind of E-textile embraces high conductivity (0.2 kΩ/sq), high air permeability (88.2 mm/s), and can be manufactured on common fabric at large scales. Due to the advantage of the interaction between the CNTs and the fabrics, the electrode shows excellent stability under harsh mechanical deformation and even after being washed. Moreover, based on a single-electrode mode triboelectric nanogenerator and electrode pattern design, our E-textile exhibits highly sensitive touch/gesture sensing performance and has potential applications for human-machine interfacing.

  12. Sleep Disturbances in Patients with Rheumatoid Arthritis | Abbasi ...

    African Journals Online (AJOL)

    Sleep Disturbances in Patients with Rheumatoid Arthritis. ... that insomnia, pain and disease intensity were the most important factors that ... that sleep disturbances are frequent in patients with RA and may contribute to disease severity.

  13. Role of Physical Attractiveness in Peer Attribution of Psychological Disturbance

    Science.gov (United States)

    Cash, Thomas F.; And Others

    1977-01-01

    The physical attractiveness stereotype was examined as it pertains to the attribution of psychological disturbance among peers. Consistent with the stereotype, attractive interviewees were judged as less disturbed with better prognosis than unattractive interviewees. (Author)

  14. Clinical implications of glycometabolic disturbances in acute coronary

    NARCIS (Netherlands)

    Timmer, Jorik Rudolf

    2005-01-01

    Prevalence of glycometabolic disturbances in patients with a suspected acute coronary syndrome is high. One in three patients has signs of disturbed glucose metabolism and this condition is associated with previous or newly diagnosed coronary artery disease. Zie: Summary

  15. Electroperturbation of human stratum corneum fine structure by high voltage pulses: a freeze-fracture electron microscopy and differential thermal analysis study.

    Science.gov (United States)

    Jadoul, A; Tanojo, H; Préat, V; Bouwstra, J A; Spies, F; Boddé, H E

    1998-08-01

    Application of high voltage pulses (HVP) to the skin has been shown to promote the transdermal drug delivery by a mechanism involving skin electroporation. The aim of this study was to detect potential changes in lipid phase and ultrastructure induced in human stratum corneum by various HVP protocols, using differential thermal analysis and freeze-fracture electron microscopy. Due to the time involved between the moment the electric field is switched off and the analysis, only "secondary" phenomena rather than primary events could be observed. A decrease in enthalpies for the phase transitions observed at 70 degrees C and 85 degrees C was detected by differential thermal analysis after HVP treatment. No changes in transition temperature could be seen. The freeze-fracture electron microscopy study revealed a dramatic perturbation of the lamellar ordering of the intercellular lipid after application of HVP. Most of the planes displayed rough surfaces. The lipid lamellae exhibited rounded off steps or a vanished stepwise order. There was no evidence for perturbation of the corneocytes content. In conclusion, the freeze-fracture electron microscopy and differential thermal analysis studies suggest that HVP application induces a general perturbation of the stratum corneum lipid ultrastructure.

  16. Assimilative Modeling of Ionospheric Disturbances with FORMOSAT-3/COSMIC and Ground-Based GPS Measurements

    Directory of Open Access Journals (Sweden)

    Xiaoqing Pi

    2009-01-01

    Full Text Available The four-dimensional Global Assimilative Ionospheric Model (GAIM is applied to a study of ionospheric disturbances. The investigation is focused on disturbance features, particularly in the altitude and latitude dimensions, at low latitudes during a geomagnetic storm on 7 August 2006, under solar minimum conditions. The modeling of storm-time ionospheric state (electron density is conducted by assimilating an unprecedented volume of line-of-sight TEC data collected by the Global Positioning System (GPS occultation receivers on board six FORMOSAT-3/COSMIC satellites and geodetic-quality GPS receivers at two hundred globally-distributed ground tracking stations.With a band-limited Kalman filter technique to update the ionospheric state, the assimilative modeling reveals a pronounced enhancement in the equatorial anomaly in the East Asia sector during dusk and evening hours. The disturbance characteristics, obtained by comparing with the quiet conditions prior to the storm also modeled in this study through data assimilation, include lifted F layer and reduced electron density in the equatorial region, enhanced density at the magnetically conjugate anomaly latitudes, and tilted feature of density increase towards higher altitudes at lower latitudes. The characteristics are attributed to the enhanced plasma fountain effect driven by an enhanced eastward zonal electric field. These results enable us to distinguish the storm-time electric field perturbations clearly from other sources during the storm. The possible origins of electric field perturbations are also discussed, including penetration of the magnetospheric electric field and wind dynamo disturbances.

  17. Thermospheric/ionospheric disturbances under quiet and magneto-perturbed conditions

    Science.gov (United States)

    Zakharov, Ivan G.; Mozgovaya, O. L.

    2003-04-01

    The basic mechanisms of ionospheric storms (IS) are investigated sufficiently full. Despite of it a quantitative forecast of ionospheric disturbance is not always satisfactory. One of the possible causes can be related to the insufficient account of a background ionospheric. In particualr using electron concentration Ne in the peak of F2-region and total electron content are shown, that the amplitude of a IS positive phase for similar magnetic storms can differ by ~1,5 times. Hence a cause of distinction can be variations in the thermosphere conditions, not reflected by known activity indices. For further research we used the incoherent scatter radar data of the Institute of ionosphere in height range 200-1000 km in the very quiet periods coming to the geomagnetic disturbance. A steady periodic disturbance in Ne during quiet conditions in all heights is established, which can be identified as tidal moda m=6. The amplitude of wave is ~15%, the phase changes with a height. The storm onset leads to an increase of the amplitudes approximately twice without a change in the phase. An ionospheric disturbance in very quiet conditions can lead to additional complicating an ionosphere reaction to magnetic storm.

  18. The interaction of land-use legacies and hurricane disturbance in subtropical wet forest: twenty-one years of change

    OpenAIRE

    Hogan, James Aaron; Zimmerman, Jess K.; Thompson, Jill; Nytch, Christopher J.; Uriarte, Maria

    2016-01-01

    Disturbance shapes plant communities over a wide variety of spatial and temporal scales. How natural and anthropogenic disturbance interact to shape ecological communities is highly variable and begs a greater understanding. We used five censuses spanning the years 1990–2011 from the 16-ha Luquillo Forest Dynamics Plot (LFDP) in northeast Puerto Rico to investigate the interplay of human land-use legacies dating to the early 20th century and two recent hurricanes (Hugo, 1989 and Georges, 1998...

  19. Scanning electron microscopy of third-instar sarcophagid (Diptera: Sarcophagidae recovered from a mummified human corpse in Thailand

    Directory of Open Access Journals (Sweden)

    Sukontason Kom

    2003-01-01

    Full Text Available The third-instar of an unidentified sarcophagid, recovered from a mummified body of a 32-yr-old Thai male was examined using scanning electron microscopy (SEM. Although the morphological features of this larva are similar to the other sarcophagid larvae, some features could be helpful for species identification, which is a basic requirement for estimation of postmortem interval in forensic investigation. These features included number and arrangement of papillae on the anterior spiracle, structure of spines, size of circumspiracular tubercles at caudal segment and branching peculiarity of the posterior spiracular hairs. This information could benefit future identification of the sarcophagid larvae that exist in Thailand.

  20. Impulsive Flocking of Dynamical Multiagent Systems with External Disturbances

    Directory of Open Access Journals (Sweden)

    Fujun Han

    2017-01-01

    Full Text Available Flocking motion of multiagent systems is influenced by various external disturbances in complex environment. By applying disturbance observer, flocking of multiagent systems with exogenous disturbances is studied. Based on the robust features of impulsive control, a distributed impulsive control protocol is presented with disturbance observer, and flocking motion of multiagent systems is analyzed. Moreover, a sufficient condition is obtained to ensure the flocking motion of multiagent systems following a leader. Finally, simulation results show the validity of the theoretical conclusion.

  1. Anthropogenic halo disturbances alter landscape and plant richness: a ripple effect.

    Science.gov (United States)

    Liu, Bingliang; Su, Jinbao; Chen, Jianwei; Cui, Guofa; Ma, Jianzhang

    2013-01-01

    Although anthropogenic landscape fragmentation is often considered as the primary threat to biodiversity, other factors such as immediate human disturbances may also simultaneously threaten species persistence in various ways. In this paper, we introduce a conceptual framework applied to recreation landscapes (RLs), with an aim to provide insight into the composite influences of landscape alteration accompanying immediate human disturbances on plant richness dynamics. These impacts largely occur at patch-edges. They can not only alter patch-edge structure and environment, but also permeate into surrounding natural matrices/patches affecting species persistence-here we term these "Halo disturbance effects" (HDEs). We categorized species into groups based on seed or pollen dispersal mode (animal- vs. wind-dispersed) as they can be associated with species richness dynamics. We evaluated the richness of the two groups and total species in our experimental landscapes by considering the distance from patch-edge, the size of RLs and the intensity of human use over a six-year period. Our results show that animal-dispersed species decreased considerably, whereas wind-dispersed species increased while their richness presented diverse dynamics at different distances from patch-edges. Our findings clearly demonstrate that anthropogenic HDEs produce ripple effects on plant, providing an experimental interpretation for the diverse responses of species to anthropogenic disturbances. This study highlights the importance of incorporating these composite threats into conservation and management strategies.

  2. Anthropogenic halo disturbances alter landscape and plant richness: a ripple effect.

    Directory of Open Access Journals (Sweden)

    Bingliang Liu

    Full Text Available Although anthropogenic landscape fragmentation is often considered as the primary threat to biodiversity, other factors such as immediate human disturbances may also simultaneously threaten species persistence in various ways. In this paper, we introduce a conceptual framework applied to recreation landscapes (RLs, with an aim to provide insight into the composite influences of landscape alteration accompanying immediate human disturbances on plant richness dynamics. These impacts largely occur at patch-edges. They can not only alter patch-edge structure and environment, but also permeate into surrounding natural matrices/patches affecting species persistence-here we term these "Halo disturbance effects" (HDEs. We categorized species into groups based on seed or pollen dispersal mode (animal- vs. wind-dispersed as they can be associated with species richness dynamics. We evaluated the richness of the two groups and total species in our experimental landscapes by considering the distance from patch-edge, the size of RLs and the intensity of human use over a six-year period. Our results show that animal-dispersed species decreased considerably, whereas wind-dispersed species increased while their richness presented diverse dynamics at different distances from patch-edges. Our findings clearly demonstrate that anthropogenic HDEs produce ripple effects on plant, providing an experimental interpretation for the diverse responses of species to anthropogenic disturbances. This study highlights the importance of incorporating these composite threats into conservation and management strategies.

  3. Optimization of Vehicular Trajectories under Gaussian Noise Disturbances

    Directory of Open Access Journals (Sweden)

    Joan Garcia-Haro

    2012-12-01

    Full Text Available Nowadays, research on Vehicular Technology aims at automating every single mechanical element of vehicles, in order to increase passengers’ safety, reduce human driving intervention and provide entertainment services on board. Automatic trajectory tracing for vehicles under especially risky circumstances is a field of research that is currently gaining enormous attention. In this paper, we show some results on how to develop useful policies to execute maneuvers by a vehicle at high speeds with the mathematical optimization of some already established mobility conditions of the car. We also study how the presence of Gaussian noise on measurement sensors while maneuvering can disturb motion and affect the final trajectories. Different performance criteria for the optimization of such maneuvers are presented, and an analysis is shown on how path deviations can be minimized by using trajectory smoothing techniques like the Kalman Filter. We finalize the paper with a discussion on how communications can be used to implement these schemes.

  4. A Multi-Wavelength Opto-Electronic Patch Sensor to Effectively Detect Physiological Changes against Human Skin Types.

    Science.gov (United States)

    Yan, Liangwen; Hu, Sijung; Alzahrani, Abdullah; Alharbi, Samah; Blanos, Panagiotis

    2017-06-21

    Different skin pigments among various ethnic group people have an impact on spectrometric illumination on skin surface. To effectively capture photoplethysmographic (PPG) signals, a multi-wavelength opto-electronic patch sensor (OEPS) together with a schematic architecture of electronics were developed to overcome the drawback of present PPG sensor. To perform a better in vivo physiological measurement against skin pigments, optimal illuminations in OEPS, whose wavelength is compatible with a specific skin type, were optimized to capture a reliable physiological sign of heart rate (HR). A protocol was designed to investigate an impact of five skin types in compliance with Von Luschan's chromatic scale. Thirty-three healthy male subjects between the ages of 18 and 41 were involved in the protocol implemented by means of the OEPS system. The results show that there is no significant difference ( p: 0.09, F = 3.0) in five group tests with the skin types across various activities throughout a series of consistent measurements. The outcome of the present study demonstrates that the OEPS, with its multi-wavelength illumination characteristics, could open a path in multiple applications of different ethnic groups with cost-effective health monitoring.

  5. A Multi-Wavelength Opto-Electronic Patch Sensor to Effectively Detect Physiological Changes against Human Skin Types

    Directory of Open Access Journals (Sweden)

    Liangwen Yan

    2017-06-01

    Full Text Available Different skin pigments among various ethnic group people have an impact on spectrometric illumination on skin surface. To effectively capture photoplethysmographic (PPG signals, a multi-wavelength opto-electronic patch sensor (OEPS together with a schematic architecture of electronics were developed to overcome the drawback of present PPG sensor. To perform a better in vivo physiological measurement against skin pigments, optimal illuminations in OEPS, whose wavelength is compatible with a specific skin type, were optimized to capture a reliable physiological sign of heart rate (HR. A protocol was designed to investigate an impact of five skin types in compliance with Von Luschan’s chromatic scale. Thirty-three healthy male subjects between the ages of 18 and 41 were involved in the protocol implemented by means of the OEPS system. The results show that there is no significant difference (p: 0.09, F = 3.0 in five group tests with the skin types across various activities throughout a series of consistent measurements. The outcome of the present study demonstrates that the OEPS, with its multi-wavelength illumination characteristics, could open a path in multiple applications of different ethnic groups with cost-effective health monitoring.

  6. Variation in Gas and Volatile Compound Emissions from Human Urine as It Ages, Measured by an Electronic Nose

    Directory of Open Access Journals (Sweden)

    Siavash Esfahani

    2016-01-01

    Full Text Available The medical profession is becoming ever more interested in the use of gas-phase biomarkers for disease identification and monitoring. This is due in part to its rapid analysis time and low test cost, which makes it attractive for many different clinical arenas. One technology that is showing promise for analyzing these gas-phase biomarkers is the electronic nose—an instrument designed to replicate the biological olfactory system. Of the possible biological media available to “sniff”, urine is becoming ever more important as it is easy to collect and to store for batch testing. However, this raises the question of sample storage shelf-life, even at −80 °C. Here we investigated the effect of storage time (years on stability and reproducibility of total gas/vapour emissions from urine samples. Urine samples from 87 patients with Type 2 Diabetes Mellitus were collected over a four-year period and stored at −80 °C. These samples were then analyzed using FAIMS (field-asymmetric ion mobility spectrometry—a type of electronic nose. It was discovered that gas emissions (concentration and diversity reduced over time. However, there was less variation in the initial nine months of storage with greater uniformity and stability of concentrations together with tighter clustering of the total number of chemicals released. This suggests that nine months could be considered a general guide to a sample shelf-life.

  7. Variation in Gas and Volatile Compound Emissions from Human Urine as It Ages, Measured by an Electronic Nose.

    Science.gov (United States)

    Esfahani, Siavash; Sagar, Nidhi M; Kyrou, Ioannis; Mozdiak, Ella; O'Connell, Nicola; Nwokolo, Chuka; Bardhan, Karna D; Arasaradnam, Ramesh P; Covington, James A

    2016-01-25

    The medical profession is becoming ever more interested in the use of gas-phase biomarkers for disease identification and monitoring. This is due in part to its rapid analysis time and low test cost, which makes it attractive for many different clinical arenas. One technology that is showing promise for analyzing these gas-phase biomarkers is the electronic nose--an instrument designed to replicate the biological olfactory system. Of the possible biological media available to "sniff", urine is becoming ever more important as it is easy to collect and to store for batch testing. However, this raises the question of sample storage shelf-life, even at -80 °C. Here we investigated the effect of storage time (years) on stability and reproducibility of total gas/vapour emissions from urine samples. Urine samples from 87 patients with Type 2 Diabetes Mellitus were collected over a four-year period and stored at -80 °C. These samples were then analyzed using FAIMS (field-asymmetric ion mobility spectrometry--a type of electronic nose). It was discovered that gas emissions (concentration and diversity) reduced over time. However, there was less variation in the initial nine months of storage with greater uniformity and stability of concentrations together with tighter clustering of the total number of chemicals released. This suggests that nine months could be considered a general guide to a sample shelf-life.

  8. Variation in Gas and Volatile Compound Emissions from Human Urine as It Ages, Measured by an Electronic Nose

    Science.gov (United States)

    Esfahani, Siavash; Sagar, Nidhi M.; Kyrou, Ioannis; Mozdiak, Ella; O’Connell, Nicola; Nwokolo, Chuka; Bardhan, Karna D.; Arasaradnam, Ramesh P.; Covington, James A.

    2016-01-01

    The medical profession is becoming ever more interested in the use of gas-phase biomarkers for disease identification and monitoring. This is due in part to its rapid analysis time and low test cost, which makes it attractive for many different clinical arenas. One technology that is showing promise for analyzing these gas-phase biomarkers is the electronic nose—an instrument designed to replicate the biological olfactory system. Of the possible biological media available to “sniff”, urine is becoming ever more important as it is easy to collect and to store for batch testing. However, this raises the question of sample storage shelf-life, even at −80 °C. Here we investigated the effect of storage time (years) on stability and reproducibility of total gas/vapour emissions from urine samples. Urine samples from 87 patients with Type 2 Diabetes Mellitus were collected over a four-year period and stored at −80 °C. These samples were then analyzed using FAIMS (field-asymmetric ion mobility spectrometry—a type of electronic nose). It was discovered that gas emissions (concentration and diversity) reduced over time. However, there was less variation in the initial nine months of storage with greater uniformity and stability of concentrations together with tighter clustering of the total number of chemicals released. This suggests that nine months could be considered a general guide to a sample shelf-life. PMID:26821055

  9. Tridimensional architecture of the collagen element in the arachnoid granulations in humans: a study on scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Conegero Celso Ivan

    2003-01-01

    Full Text Available The arachnoid granulations of adult individual of both sexes were studied through scanning electron microscopy. The dura mater and arachnoid meninges of individuals were collected at the Service of Death Verification of São Paulo - USP and fixed in Karnovsky solution. After this period the material was prepared for analysis in electron microscope. Our results demonstrated that the arachnoid granulations are formed by a pedicle, body and apex, being surrounded by a capsule of connective tissue, which in turn is composed of, basically, bundles of collagen fibers that line pores of different shapes and sizes. The smaller pores are lined by tiny bundles and are located at the apical region of the granulation and the larger are lined by thicker bundles and are located at the lateral regions. In the body we verified that the bundles of collagen fibers compose a fibrous meshwork and in some regions these bundles have circular orientation, forming pores similar to those found at the region of the capsule.

  10. The Uncontrollable Mnemonic Fragments within Consciousness Reflecting Ophelia’s and Lady Macbeth’s Disturbed Minds

    Directory of Open Access Journals (Sweden)

    Ekmekçioğlu Neslihan

    2015-12-01

    Full Text Available Memory plays an important role in most of Shakespeare’s plays. Shakespeare delves into the dark realms of human consciousness to reflect the disturbed minds and gnawing consciences of his characters with a profound psychological insight into the human psyche. Time, memory, madness and death seem to be the basic issues dealt with in his canon. My paper will address the uncontrollable mnemonic fragments within the human consciousness which reflect past traumas, fears and disturbances and will examine the cases of Ophelia and Lady Macbeth from a feminist reading of women.

  11. Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells

    OpenAIRE

    Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; F?rste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

    2016-01-01

    The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothe...

  12. Mapping forest canopy disturbance in the Upper Great Lakes, USA

    Science.gov (United States)

    James D. Garner; Mark D. Nelson; Brian G. Tavernia; Charles H. (Hobie) Perry; Ian W. Housman

    2015-01-01

    A map of forest canopy disturbance was generated for Michigan, Wisconsin, and most of Minnesota using 42 Landsat time series stacks (LTSS) and a vegetation change tracker (VCTw) algorithm. Corresponding winter imagery was used to reduce commission errors of forest disturbance by identifying areas of persistent snow cover. The resulting disturbance age map was classed...

  13. Conservation of disturbance-dependent birds in eastern North America

    Science.gov (United States)

    William C. Hunter; David A. Buehler; Ronald A. Canterbury; John L. Confer; Paul B. Hamel

    2001-01-01

    Populations of most bird species associated with grassland, shrub-scrub habitats, and disturbed areas in forested habitats (hereafter all referred to as disturbance-dependent species) have declined steeply. However, a widespread perception exists that disturbance-dependent species are merely returning to population levels likely found by the first European explorers...

  14. Changes in Soil Fungal Community Structure with Increasing Disturbance Frequency.

    Science.gov (United States)

    Cho, Hyunjun; Kim, Mincheol; Tripathi, Binu; Adams, Jonathan

    2017-07-01

    Although disturbance is thought to be important in many ecological processes, responses of fungal communities to soil disturbance have been little studied experimentally. We subjected a soil microcosm to physical disturbance, at a range of frequencies designed to simulate ecological disturbance events. We analyzed the fungal community structure using Illumina HiSeq sequencing of the ITS1 region. Fungal diversity was found to decline with the increasing disturbance frequencies, with no sign of the "humpback" pattern found in many studies of larger sedentary organisms. There is thus no evidence of an effect of release from competition resulting from moderate disturbance-which suggests that competition and niche overlap may not be important in limiting soil fungal diversity. Changing disturbance frequency also led to consistent differences in community composition. There were clear differences in OTU-level composition, with different disturbance treatments each having distinct fungal communities. The functional profile of fungal groups (guilds) was changed by the level of disturbance frequency. These predictable differences in community composition suggest that soil fungi can possess different niches in relation to disturbance frequency, or time since last disturbance. Fungi appear to be most abundant relative to bacteria at intermediate disturbance frequencies, on the time scale we studied here.

  15. Development of a Scale To Assess Emotional Disturbance.

    Science.gov (United States)

    Epstein, Michael H.; Cullinan, Douglas; Ryser, Gail; Pearson, Nils

    2002-01-01

    This study reports on the standardization of the Scale for Assessing Emotional Disturbance. Data collected on 2,266 typical students (ages 5- 18) and 1,371 students with emotional disturbances led to the identification of six behavioral problem factors that correspond to the federal definition of emotional disturbance and were highly internally…

  16. Suppressing non-periodically repeating disturbances in mechanical servo systems

    NARCIS (Netherlands)

    Tousain, R.L.; Boissy, J.C.; Norg, M.L.; Steinbuch, M.; Bosgra, O.H.

    1998-01-01

    Non-periodically repeating (NPR) disturbances are fixed-shape disturbances that occur randomly in time. We can provide a control system with the capability to suppress this type of disturbance by adding in parallel to the input of the nominal feedback controller a learning look-up-table based

  17. Long-term disturbance dynamics and resilience of tropical peat swamp forests.

    Science.gov (United States)

    Cole, Lydia E S; Bhagwat, Shonil A; Willis, Katherine J

    2015-01-01

    1. The coastal peat swamp forests of Sarawak, Malaysian Borneo, are undergoing rapid conversion, predominantly into oil palm plantations. This wetland ecosystem is assumed to have experienced insignificant disturbance in the past, persisting under a single ecologically-stable regime. However, there is limited knowledge of the past disturbance regime, long-term functioning and fundamentally the resilience of this ecosystem to changing natural and anthropogenic perturbations through time. 2. In this study, long-term ecological data sets from three degraded peatlands in Sarawak were collected to shed light on peat swamp forest dynamics. Fossil pollen and charcoal were counted in each sedimentary sequence to reconstruct vegetation and investigate responses to past environmental disturbance, both natural and anthropogenic. 3. Results demonstrate that peat swamp forest taxa have dominated these vegetation profiles throughout the last c . 2000-year period despite the presence of various drivers of disturbance. Evidence for episodes of climatic variability, predominantly linked to ENSO events, and wildfires is present throughout. However, in the last c . 500 years, burning and indicators of human disturbance have elevated beyond past levels at these sites, concurrent with a reduction in peat swamp forest pollen. 4. Two key insights have been gained through this palaeoecological analysis: (i) peat swamp forest vegetation has demonstrated resilience to disturbance caused by burning and climatic variability in Sarawak in the late Holocene, however (ii) coincident with increased fire combined with human impact c . 500 years ago, these communities started to decline. 5. Synthesis . Sarawak's coastal peat swamps have demonstrated resilience to past natural disturbances, with forest vegetation persisting through episodes of fire and climatic variability. However, palaeoecological data presented here suggest that recent, anthropogenic disturbances are of a greater magnitude

  18. Forest disturbance interactions and successional pathways in the Southern Rocky Mountains

    Science.gov (United States)

    Lu Liang,; Hawbaker, Todd J.; Zhu, Zhiliang; Xuecao Li,; Peng Gong,

    2016-01-01

    The pine forests in the southern portion of the Rocky Mountains are a heterogeneous mosaic of disturbance and recovery. The most extensive and intensive stress and mortality are received from human activity, fire, and mountain pine beetles (MPB;Dendroctonus ponderosae). Understanding disturbance interactions and disturbance-succession pathways are crucial for adapting management strategies to mitigate their impacts and anticipate future ecosystem change. Driven by this goal, we assessed the forest disturbance and recovery history in the Southern Rocky Mountains Ecoregion using a 13-year time series of Landsat image stacks. An automated classification workflow that integrates temporal segmentation techniques and a random forest classifier was used to examine disturbance patterns. To enhance efficiency in selecting representative samples at the ecoregion scale, a new sampling strategy that takes advantage of the scene-overlap among adjacent Landsat images was designed. The segment-based assessment revealed that the overall accuracy for all 14 scenes varied from 73.6% to 92.5%, with a mean of 83.1%. A design-based inference indicated the average producer’s and user’s accuracies for MPB mortality were 85.4% and 82.5% respectively. We found that burn severity was largely unrelated to the severity of pre-fire beetle outbreaks in this region, where the severity of post-fire beetle outbreaks generally decreased in relation to burn severity. Approximately half the clear-cut and burned areas were in various stages of recovery, but the regeneration rate was much slower for MPB-disturbed sites. Pre-fire beetle outbreaks and subsequent fire produced positive compound effects on seedling reestablishment in this ecoregion. Taken together, these results emphasize that although multiple disturbances do play a role in the resilience mechanism of the serotinous lodgepole pine, the overall recovery could be slow due to the vast area of beetle mortality.

  19. Searching for resilience: addressing the impacts of changing disturbance regimes on forest ecosystem services

    Science.gov (United States)

    Seidl, Rupert; Spies, Thomas A.; Peterson, David L.; Stephens, Scott L.; Hicke, Jeffrey A.

    2016-01-01

    Summary 1. The provisioning of ecosystem services to society is increasingly under pressure from global change. Changing disturbance regimes are of particular concern in this context due to their high potential impact on ecosystem structure, function and composition. Resilience-based stewardship is advocated to address these changes in ecosystem management, but its operational implementation has remained challenging. 2. We review observed and expected changes in disturbance regimes and their potential impacts on provisioning, regulating, cultural and supporting ecosystem services, concentrating on temperate and boreal forests. Subsequently, we focus on resilience as a powerful concept to quantify and address these changes and their impacts, and present an approach towards its operational application using established methods from disturbance ecology. 3. We suggest using the range of variability concept – characterizing and bounding the long-term behaviour of ecosystems – to locate and delineate the basins of attraction of a system. System recovery in relation to its range of variability can be used to measure resilience of ecosystems, allowing inferences on both engineering resilience (recovery rate) and monitoring for regime shifts (directionality of recovery trajectory). 4. It is important to consider the dynamic nature of these properties in ecosystem analysis and management decision-making, as both disturbance processes and mechanisms of resilience will be subject to changes in the future. Furthermore, because ecosystem services are at the interface between natural and human systems, the social dimension of resilience (social adaptive capacity and range of variability) requires consideration in responding to changing disturbance regimes in forests. 5. Synthesis and applications. Based on examples from temperate and boreal forests we synthesize principles and pathways for fostering resilience to changing disturbance regimes in ecosystem management. We

  20. How development and disturbance of biological soil crust do affect runoff and erosion in drylands?

    Energy Technology Data Exchange (ETDEWEB)

    Chamizo, S.; Canton, Y.; Afana, A.; Lazaro, R.; Domingo, F.; Sole-Benet, A.

    2009-07-01

    Deserts and semiarid ecosystems (shrub lands and grasslands) are the largest terrestrial biome, covering more than 40% of the Earth's terrestrial surface and Biological Soil Crusts (BSCs) are the predominant surface type in most of those ecosystems covering up to 70% of its surface. BSCs have been demonstrated to be very vulnerable to disturbance due to human activities and their loss has been implicated as a factor leading to accelerate soil erosion and other forms of land degradation. Incorporation of the response of different type of soil crusts and the effects of the their disturbance is likely t