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Sample records for morphological factors influencing

  1. Influences of Environmental Factors on Leaf Morphology of Chinese Jujubes

    PubMed Central

    Li, Xiaopeng; Li, Yupeng; Zhang, Zhong; Li, Xingang

    2015-01-01

    Rainfall and temperature are the primary limiting factors for optimum quality and yield of cultivated jujube (Ziziphus jujuba Mill.). Adaptation to arid and cool environments has been and remains an important goal of many jujube improvement programs. This study summarized the survey results of 116 Chinese jujube varieties grown at 33 sites in China. The objective was to identify the environmental factors that influence leaf morphology, and the implications for breeding and introduction of new jujube varieties. Jujube leaf morphological traits were evaluated for their potential relationships with mean annual temperature (MAT) and mean annual precipitation (MAP). The results showed that many leaf morphological traits had a strong linear relationship with local precipitation and temperature. Longer veins per unit area (VLA) and reduced leaf area and leaf perimeter were typical of arid areas. VLA was inversely related to MAT and MAP at the centers of origin of jujube. There was a positive relationship between leaf shape (perimeter2/area) and both MAT and MAP. These results indicated that leaf vein traits of Chinese jujubes might have resulted from their adaptation to environmental factors in the course of long-term evolution. Principal component analysis allocated the 116 jujube varieties to three different groups, differentiated on the basis of morphological and physiological leaf characteristics. Jujube varieties from the Hebei, Shandong, Henan, southern Shanxi and central Shaanxi provinces were closely related, as were varieties from northwest Shanxi and northeast Shaanxi provinces, and varieties from the Gansu and Ningxia provinces. These close relationships were partially attributed to the frequent exchanges of varieties within each group. Leaf venation characteristics might be used as reference indices for jujube variety introduction between different locations. PMID:26020971

  2. Leaf morphological and anatomical traits from tropical to temperate coniferous forests: Mechanisms and influencing factors.

    PubMed

    Tian, Miao; Yu, Guirui; He, Nianpeng; Hou, Jihua

    2016-01-22

    Leaf traits may reflect the adaptation mechanisms of plants to the environment. In this study, we investigated leaf morphological and anatomical traits in nine cold-temperate to tropical forests along a 4,200-km transect to test how they vary across latitudinal gradients. The results showed that leaf dry weight decreased (P < 0.05), while specific leaf area (SLA) increased (P < 0.05) with increasing latitude. Stomatal length and stomatal density did not change significantly, while stomatal pore area index increased (P < 0.05) with increasing latitude. The palisade-leaf mesophyll thickness ratio increased (P < 0.01), while the spongy-leaf mesophyll thickness ratio decreased, with increasing latitude (P < 0.01). Climate and leaf nutrients were the main factors that regulated leaf morphological and anatomical traits. Furthermore, we identified positive correlations between leaf area and leaf dry weight, leaf thickness and palisade mesophyll thickness, but negative correlations between stomatal length and stomatal density (all P < 0.01). The observed negative correlations represented the adaptive mechanisms of leaves through their morphological and anatomical traits. These findings provided new insights into the responses of leaf morphological and anatomical traits to climate changes and important parameters for future model optimization.

  3. Leaf morphological and anatomical traits from tropical to temperate coniferous forests: Mechanisms and influencing factors

    PubMed Central

    Tian, Miao; Yu, Guirui; He, Nianpeng; Hou, Jihua

    2016-01-01

    Leaf traits may reflect the adaptation mechanisms of plants to the environment. In this study, we investigated leaf morphological and anatomical traits in nine cold-temperate to tropical forests along a 4,200-km transect to test how they vary across latitudinal gradients. The results showed that leaf dry weight decreased (P < 0.05), while specific leaf area (SLA) increased (P < 0.05) with increasing latitude. Stomatal length and stomatal density did not change significantly, while stomatal pore area index increased (P < 0.05) with increasing latitude. The palisade-leaf mesophyll thickness ratio increased (P < 0.01), while the spongy-leaf mesophyll thickness ratio decreased, with increasing latitude (P < 0.01). Climate and leaf nutrients were the main factors that regulated leaf morphological and anatomical traits. Furthermore, we identified positive correlations between leaf area and leaf dry weight, leaf thickness and palisade mesophyll thickness, but negative correlations between stomatal length and stomatal density (all P < 0.01). The observed negative correlations represented the adaptive mechanisms of leaves through their morphological and anatomical traits. These findings provided new insights into the responses of leaf morphological and anatomical traits to climate changes and important parameters for future model optimization. PMID:26796339

  4. Management, morphological, and environmental factors influencing Douglas-fir bark furrows in the Oregon Coast Range

    USGS Publications Warehouse

    Sheridan, Christopher D.; Puettmann, Klaus J.; Huso, Manuela M.P.; Hagar, Joan C.; Falk, Kristen R.

    2013-01-01

    Many land managers in the Pacific Northwest have the goal of increasing late-successional forest structures. Despite the documented importance of Douglas-fir tree bark structure in forested ecosystems, little is known about factors influencing bark development and how foresters can manage development. This study investigated the relative importance of tree size, growth, environmental factors, and thinning on Douglas-fir bark furrow characteristics in the Oregon Coast Range. Bark furrow depth, area, and bark roughness were measured for Douglas-fir trees in young heavily thinned and unthinned sites and compared to older reference sites. We tested models for relationships between bark furrow response and thinning, tree diameter, diameter growth, and environmental factors. Separately, we compared bark responses measured on trees used by bark-foraging birds with trees with no observed usage. Tree diameter and diameter growth were the most important variables in predicting bark characteristics in young trees. Measured environmental variables were not strongly related to bark characteristics. Bark furrow characteristics in old trees were influenced by tree diameter and surrounding tree densities. Young trees used by bark foragers did not have different bark characteristics than unused trees. Efforts to enhance Douglas-fir bark characteristics should emphasize retention of larger diameter trees' growth enhancement.

  5. A quantitative study of factors influencing lamellar eutectic morphology during solidification

    NASA Technical Reports Server (NTRS)

    Kaukler, W. F. S.

    1981-01-01

    The factors that influence the shape of the solid-liquid interface of a lamellar binary eutectic alloy are evaluated. Alloys of carbon tetrabromide and hexachloroethane which serve as a transparent analogue of lamellar metallic eutectics are used. The observed interface shapes are analyzed by computer-aided methods. The solid-liquid interfacial free energies of each of the individual phases comprising the eutectic system are measured as a function of composition using a 'grain boundary groove' technique. The solid-liquid interfacial free energy of the two phases are evaluated directly from the eutectic interface. The phase diagram for the system, the heat of fusion as a function of composition, and the density as a function of composition are measured. The shape of the eutectic interface is controlled mainly by the solid-liquid and solid-solid interfacial free energy relationships at the interface and by the temperature gradient present, rather than by interlamellar diffusion in the liquid at the interface, over the range of growth rates studied.

  6. Factors Influencing Occurrence, Scale, Mobility, Runout, and Morphology of Mass Movements on the Continental Slope

    DTIC Science & Technology

    2016-06-07

    failure. We develop improved correlations between engineering classifications and strength factors. We measure excess pore water pressures in situ. We...data obtained by Lee as part of a sediment pollutant transport study. We have prepared maps of the Los Angeles margin that show the distribution of...landscape evolution modelers. RELATED PROJECTS Lee has developed a USGS project to investigate sediment and pollutant transport on the Los Angeles margin

  7. Influence of basement membrane proteins and endothelial cell-derived factors on the morphology of human fetal-derived astrocytes in 2D.

    PubMed

    Levy, Amanda F; Zayats, Maya; Guerrero-Cazares, Hugo; Quiñones-Hinojosa, Alfredo; Searson, Peter C

    2014-01-01

    Astrocytes are the most prevalent type of glial cell in the brain, participating in a variety of diverse functions from regulating cerebral blood flow to controlling synapse formation. Astrocytes and astrocyte-conditioned media are widely used in models of the blood-brain barrier (BBB), however, very little is known about astrocyte culture in 2D. To test the hypothesis that surface coating and soluble factors influence astrocyte morphology in 2D, we quantitatively analyzed the morphology of human fetal derived astrocytes on glass, matrigel, fibronectin, collagen IV, and collagen I, and after the addition soluble factors including platelet-derived growth factor (PDGF), laminin, basic fibroblast growth factor (bFGF), and leukemia inhibitory factor (LIF). Matrigel surface coatings, as well as addition of leukemia inhibitory factor (LIF) to the media, were found to have the strongest effects on 2D astrocyte morphology, and may be important in improving existing BBB models. In addition, the novel set of quantitative parameters proposed in this paper provide a test for determining the influence of compounds on astrocyte morphology, both to screen for new endothelial cell-secreted factors that influence astrocytes, and to determine in a high-throughput way which factors are important for translation to more complex, 3D BBB models.

  8. [Morphological verification problems of Chernobyl factor influence on the prostate of coalminers of Donbas--liquidators of Chernobyl accident].

    PubMed

    Danylov, Iu V; Motkov, K V; Shevchenko, T I

    2013-12-01

    Problem of a diagnostic of Chernobyl factor influences on different organs and systems of Chernobyl accident liquidators are remain actually until now. Though morbidly background which development at unfavorable work conditions in underground coalminers prevents from objective identification features of Chernobyl factor influences. The qualitative and quantitative histological and immunohistochemical law of morphogenesis changes in prostate of Donbas's coalminer-non-liquidators Chernobyl accident in comparison with the group of Donbas's coalminers-liquidators Chernobyl accident which we were stationed non determined problem. This reason stipulates to development and practical use of mathematical model of morphogenesis of a prostatic gland changes.

  9. [Morphological verification problems of Chernobyl factor influence on the testis of coal miners of Donbas-liquidators of Chernobyl accident].

    PubMed

    Danylov, Iu V; Motkov, K V; Shevchenko, T I

    2013-01-01

    Problem of a diagnostic of Chernobyl factor influences on different organs and systems of Chernobyl accident liquidators are remain actually until now. Though morbidly background which development at unfavorable work conditions in underground coalminers prevents from objective identification features of Chernobyl factor influences. The qualitative and quantitative histological and immunohistochemical law of morphogenesis changes in testis of Donbas's coalminer - non-liquidators Chernobyl accident in comparison with the group of Donbas's coalminers-liquidators Chernobyl accident, which we were stationed non determined problem. This reason stipulates to development and practical use of mathematical model of morphogenesis of a testis changes.

  10. Factors Influencing Army Maintenance

    DTIC Science & Technology

    1989-01-01

    ARI Research Note 89-11 (N 00 Factors Influencing Army Maintenance LOloD Debra C. Evans and J. Thomas Roth Applied Science Associates, Inc. for...1.2.7 .2.7.C.1 11. TITLE (Include Security ClassifIcarIon) Factors Influencing Army Maintenance i2. FERSONAL AuTtiOR(S) Evans, Debra C., and Roth, J...y • ’ Factors and variables that influence maintenance for systems and related manpower, per- sonnel, and training (MPT) characteristics were

  11. [Natural factors influencing sleep].

    PubMed

    Jurkowski, Marek K; Bobek-Billewicz, Barbara

    2007-01-01

    Sleep is a universal phenomenon of human and animal lives, although the importance of sleep for homeo-stasis is still unknown. Sleep disturbances influence many behavioral and physiologic processes, leading to health complications including death. On the other hand, sleep improvement can beneficially influence the course of healing of many disorders and can be a prognostic of health recovery. The factors influencing sleep have different biological and chemical origins. They are classical hormones, hypothalamic releasing and inhibitory hormones, neuropeptides, peptides and others as cytokines, prostaglandins, oleamid, adenosine, nitric oxide. These factors regulate most physiologic processes and are likely elements integrating sleep with physiology and physiology with sleep in health and disorders.

  12. Factors affecting spermatozoa morphology in beef bulls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate factors affecting sperm morphology of bulls (n=908) collected at 320 days of age. Bulls were a composite breed (50% Red Angus, 25% Charolais, and 25% Tarentaise) born from 2002 to 2008 to dams fed levels of feed during mid and late gestation that were expe...

  13. Neuron Morphology Influences Axon Initial Segment Plasticity.

    PubMed

    Gulledge, Allan T; Bravo, Jaime J

    2016-01-01

    In most vertebrate neurons, action potentials are initiated in the axon initial segment (AIS), a specialized region of the axon containing a high density of voltage-gated sodium and potassium channels. It has recently been proposed that neurons use plasticity of AIS length and/or location to regulate their intrinsic excitability. Here we quantify the impact of neuron morphology on AIS plasticity using computational models of simplified and realistic somatodendritic morphologies. In small neurons (e.g., dentate granule neurons), excitability was highest when the AIS was of intermediate length and located adjacent to the soma. Conversely, neurons having larger dendritic trees (e.g., pyramidal neurons) were most excitable when the AIS was longer and/or located away from the soma. For any given somatodendritic morphology, increasing dendritic membrane capacitance and/or conductance favored a longer and more distally located AIS. Overall, changes to AIS length, with corresponding changes in total sodium conductance, were far more effective in regulating neuron excitability than were changes in AIS location, while dendritic capacitance had a larger impact on AIS performance than did dendritic conductance. The somatodendritic influence on AIS performance reflects modest soma-to-AIS voltage attenuation combined with neuron size-dependent changes in AIS input resistance, effective membrane time constant, and isolation from somatodendritic capacitance. We conclude that the impact of AIS plasticity on neuron excitability will depend largely on somatodendritic morphology, and that, in some neurons, a shorter or more distally located AIS may promote, rather than limit, action potential generation.

  14. Secreted or nonsecreted forms of acidic fibroblast growth factor produced by transfected epithelial cells influence cell morphology, motility, and invasive potential.

    PubMed Central

    Jouanneau, J; Gavrilovic, J; Caruelle, D; Jaye, M; Moens, G; Caruelle, J P; Thiery, J P

    1991-01-01

    Addition of exogenous acidic fibroblast growth factor (aFGF) to NBT-II epithelial carcinoma cells results in fibroblastic transformation and cell motility. We have generated aFGF-producing NBT-II cells by transfection with recombinant expression vectors containing human aFGF cDNA, or the human aFGF cDNA coupled to a signal peptide (SP) sequence. The effects of the nonsecreted and the secreted 16-kDa growth factor on the morphology, motility, and cell invasive potential (gelatinase activity) were compared. aFGF coupled to a SP was actively secreted out of the producing cells. The secretion of aFGF was not necessary for induction of gelatinase activity, as this was observed in NBT-II cells producing aFGF with or without SP. Production of aFGF, whether secreted or not secreted, resulted in increased in vitro motility of most isolated clones; however, there was no correlation between aFGF level and motility rate. The data suggest that expression of aFGF in NBT-II cells induces metastatic potential through an autocrine or intracrine mechanism. Images PMID:1707175

  15. Influence of sulfur in coals on char morphology and combustion

    SciTech Connect

    Marsh, H.

    1991-01-01

    During coal carbonization (pyrolysis), as during the combustion process of pulverized coal in a combustor, not all of the sulfur is released. Significant proportions become pat of the structure of the resultant coke and char. The combustion process of the char within the flames of the combustor in influenced dominantly by char morphology. This, in turn, controls the accessibility of oxidizing gases to the surfaces of the carbonaceous substance of the char. Mineral matter content, its extent and state of distribution, also exerts an influence on char morphology created during pyrolysis/carbonization. This complexity of coal renders it a very difficult material to study, systematically, to distinguish and separate out the contributing factors which influence combustion characteristics. Therefore, in such circumstances, it is necessary to simplify the systems by making use of model chars/cokes/carbons which can be made progressively more complex, but in a controlled way. In this way complicating influence in chars from coals can be eliminated, so enabling specific influences to be studied independently. It is important to note that preliminary work by Marsh and Gryglewicz (1990) indicated that levels of sulfur of about 3 to 5 wt % can reduce reactivities by 10 to 25%. The overall purpose of the study is to provide meaningful kinetic data to establish, quantitatively, the influence of organically-bound sulfur on the reactivity of carbons, and to ascertain if gasification catalysts are effective in the preferential removal of sulfur from the chars.

  16. Influence of prepolymer composition on polyurethane morphology

    NASA Astrophysics Data System (ADS)

    Krishnamoorthy, Jayaraman; Jeong, Young Gyu; Hashida, Tomoko; Hsu, Shaw Ling

    2004-03-01

    Polyurethane chemistry is one of the most studied subjects. Yet many aspects remain unexplained. Polyurethanes are synthesized by the reaction of diisocyanate with diol in the presence of nucleophilic catalysts. Polyurethane prepolymers are obtained by reacting the polyester diol / polyether diol with diisocyanate, with [NCO] / [OH] > 1, resulting in isocyanate-terminated polyester/polyether mixture. Prepolymers thus synthesized can be cured at a later stage to realize various morphologies and structures. Though the initial composition and the final morphology are known, little is known about the intermediate prepolymer mixture. Due to the different reactivity of primary and secondary hydroxyl groups in the polyester and polyether towards isocyanate, prepolymer has a non-random distribution in terms of composition as blends and copolymers. Our aim is to characterize the prepolymer by different techniques and study how the different prepolymer composition, with varying polyester and polyether ratio, affects the morphology and phase separation kinetics of the final product.

  17. Physiological and morphological factors associated with successful fencing performance.

    PubMed

    Stewart, K J; Peredo, A R; Williams, C M

    1977-09-01

    The relation between fencing success during a season of intercollegiate competition and various physiological and morphological variables were determined in 14 fencers. Bivariate and multiple regression analysis was used to determine the extent to which the independent variables, individually and collectively, accounted for the variance in two measures of fencing success. The fencing scores correlated significantly with VE max, Vo2 max, the 2 km run, and weight, while there was no significant correlation between the fencing scores and submaximal heart rate at 6 mph, and 1 min steptest score, or other morphological measurements. Cardiorespiratory fitness variables of Vo2 max and VE max accounted for the greatest variance in each of the two fencing scores (57.7 and 58.1%, respectively). Although morphological factors play a role in fencing success, their influence is small when physiological factors are accounted for. Future energy-cost studies are suggested to determine the physiological basis for the relationship between cardiorespiratory fitness and fencing success.

  18. Phonological Awareness: Factors of Influence

    ERIC Educational Resources Information Center

    Frohlich, Linda Paulina; Petermann, Franz; Metz, Dorothee

    2013-01-01

    Early child development is influenced by various genetic and environmental factors. This study aims to identify factors that affect the phonological awareness of preschool and first grade children. Based on a sample of 330 German-speaking children (mean age = 6.2 years) the following domains were evaluated: Parent factors, birth and pregnancy,…

  19. Factors That Influence Teacher Attrition.

    ERIC Educational Resources Information Center

    Gonzalez, Patricia

    1995-01-01

    External, employment, and personal factors which influence teacher decisions to stay, leave, or transfer from teaching assignments are discussed, with emphasis on special education teachers. Factors attributed to teacher attrition in urban and rural environments also are briefly reviewed, along with attrition of related services professionals.…

  20. Factors influencing permanent teeth eruption. Part one--general factors.

    PubMed

    Almonaitiene, Ruta; Balciuniene, Irena; Tutkuviene, Janina

    2010-01-01

    Variation in the normal eruption of teeth is a common finding, but significant deviation from established norms should alert the clinician to take some diagnostic procedures in order to evaluate patient health and development. Disturbance in tooth eruption time could be a symptom of general condition or indication of altered physiology and craniofacial development. The aim of this review is to analyze general factors that could influence permanent teeth eruption. The articles from 1965 to 2009 in English related to topic were identified. 84 articles were selected for data collection. Although permanent teeth eruption is under significant genetic control, various general factors such as gender, socioeconomic status, craniofacial morphology, body composition can influence this process. Most significant disturbance in teeth emergence is caused by systemic diseases and syndromes.

  1. Factors Influencing College Science Success

    ERIC Educational Resources Information Center

    Tai, Robert H.; Sadler, Philip M.; Mintzes, Joel J.

    2006-01-01

    In this paper, the authors report some of the salient findings of a large-scale, four-year national study, conducted at the Harvard-Smithsonian Center for Astrophysics, entitled "Factors Influencing College Science Success" (FICSS), which surveyed college students who enrolled in first-year biology, chemistry, and physics courses…

  2. Soft Factors Influence College Enrollment

    ERIC Educational Resources Information Center

    Fogg, Neeta P.; Harrington, Paul E.

    2010-01-01

    Evidence about the role that "soft factors" like student engagement and school environment play in influencing whether high school students go on to enroll in college is hard to come by. Over the past two years, the Center for Labor Market Studies (CLMS) of Northeastern University, with support from the Nellie Mae Education Foundation…

  3. Habitat influence in the morphological diversity of coastal fish assemblages

    NASA Astrophysics Data System (ADS)

    Farré, Marc; Lombarte, Antoni; Recasens, Laura; Maynou, Francesc; Tuset, Victor M.

    2015-05-01

    Ecological diversity based on quantitative data is widely used to characterize biological communities, but recently morphological and functional traits have also been used to analyse the structure of fish assemblages. This diversity and structure is usually linked to variables such as habitat complexity and composition, depth, and spatial and temporal variations. In this study, several fish assemblages off the Catalan coast (NW Mediterranean) were ecologically and morphologically analysed and compared. The morphological analysis was performed from body shape of fish species using geometric morphology. Moreover, a canonical correspondence analysis (CCA) was used to analyse the effect of local environmental variables such as habitat, locality and depth on the composition and abundance of assemblages. The results revealed greater differences among assemblages in the clustering performed from morphological data, which is linked to habitat complexity, than those shown by the ecological analysis. Moreover, the CCA analysis indicated that type of substratum and the location significantly influenced the composition and structure of the fish assemblages. These results evidenced that morphology provides different and complementary information than ecological analysis because it allows to predict the ecological and functional habits of species within the community, helping to improve the understanding of the fish assemblages structure.

  4. Factors influencing susceptibility to metals.

    PubMed Central

    Gochfeld, M

    1997-01-01

    Although the long-neglected field of human susceptibility to environmental toxicants is currently receiving renewed attention, there is only scant literature on factors influencing susceptibility to heavy metals. Genetic factors may influence the availability of sulfhydryl-containing compounds such as glutathione and metallothionein, which modify the distribution and toxicity of certain metals. Age and gender play a role in modifying uptake and distribution, although the mechanisms are often obscure. Concurrent exposure to divalent cations may enhance or reduce the toxicity of certain metals through competition for receptor-mediated transport or targets. Increasing use of biomarkers of exposure should greatly increase our understanding of the underlying distribution of susceptibility to various environmental agents. PMID:9255566

  5. Factors influencing pacing in triathlon.

    PubMed

    Wu, Sam Sx; Peiffer, Jeremiah J; Brisswalter, Jeanick; Nosaka, Kazunori; Abbiss, Chris R

    2014-01-01

    Triathlon is a multisport event consisting of sequential swim, cycle, and run disciplines performed over a variety of distances. This complex and unique sport requires athletes to appropriately distribute their speed or energy expenditure (ie, pacing) within each discipline as well as over the entire event. As with most physical activity, the regulation of pacing in triathlon may be influenced by a multitude of intrinsic and extrinsic factors. The majority of current research focuses mainly on the Olympic distance, whilst much less literature is available on other triathlon distances such as the sprint, half-Ironman, and Ironman distances. Furthermore, little is understood regarding the specific physiological, environmental, and interdisciplinary effects on pacing. Therefore, this article discusses the pacing strategies observed in triathlon across different distances, and elucidates the possible factors influencing pacing within the three specific disciplines of a triathlon.

  6. Factors influencing pacing in triathlon

    PubMed Central

    Wu, Sam SX; Peiffer, Jeremiah J; Brisswalter, Jeanick; Nosaka, Kazunori; Abbiss, Chris R

    2014-01-01

    Triathlon is a multisport event consisting of sequential swim, cycle, and run disciplines performed over a variety of distances. This complex and unique sport requires athletes to appropriately distribute their speed or energy expenditure (ie, pacing) within each discipline as well as over the entire event. As with most physical activity, the regulation of pacing in triathlon may be influenced by a multitude of intrinsic and extrinsic factors. The majority of current research focuses mainly on the Olympic distance, whilst much less literature is available on other triathlon distances such as the sprint, half-Ironman, and Ironman distances. Furthermore, little is understood regarding the specific physiological, environmental, and interdisciplinary effects on pacing. Therefore, this article discusses the pacing strategies observed in triathlon across different distances, and elucidates the possible factors influencing pacing within the three specific disciplines of a triathlon. PMID:25258562

  7. Factors influencing healthcare service quality

    PubMed Central

    Mosadeghrad, Ali Mohammad

    2014-01-01

    Background: The main purpose of this study was to identify factors that influence healthcare quality in the Iranian context. Methods: Exploratory in-depth individual and focus group interviews were conducted with 222 healthcare stakeholders including healthcare providers, managers, policy-makers, and payers to identify factors affecting the quality of healthcare services provided in Iranian healthcare organisations. Results: Quality in healthcare is a production of cooperation between the patient and the healthcare provider in a supportive environment. Personal factors of the provider and the patient, and factors pertaining to the healthcare organisation, healthcare system, and the broader environment affect healthcare service quality. Healthcare quality can be improved by supportive visionary leadership, proper planning, education and training, availability of resources, effective management of resources, employees and processes, and collaboration and cooperation among providers. Conclusion: This article contributes to healthcare theory and practice by developing a conceptual framework that provides policy-makers and managers a practical understanding of factors that affect healthcare service quality. PMID:25114946

  8. Characterising natural bedform morphology and its influence on flow

    NASA Astrophysics Data System (ADS)

    Lefebvre, Alice; Paarlberg, Andries J.; Winter, Christian

    2016-10-01

    Bedforms such as dunes and ripples are ubiquitous in rivers and coastal seas, and commonly described as triangular shapes from which height and length are calculated to estimate hydrodynamic and sediment dynamic parameters. Natural bedforms, however, present a far more complicated morphology; the difference between natural bedform shape and the often assumed triangular shape is usually neglected, and how this may affect the flow is unknown. This study investigates the shapes of natural bedforms and how they influence flow and shear stress, based on four datasets extracted from earlier studies on two rivers (the Rio Paraná in Argentina, and the Lower Rhine in The Netherlands). The most commonly occurring morphological elements are a sinusoidal stoss side made of one segment and a lee side made of two segments, a gently sloping upper lee side and a relatively steep (6 to 21°) slip face. A non-hydrostatic numerical model, set up using Delft3D, served to simulate the flow over fixed bedforms with various morphologies derived from the identified morphological elements. Both shear stress and turbulence increase with increasing slip face angle and are only marginally affected by the dimensions and positions of the upper and lower lee side. The average slip face angle determined from the bed profiles is 14°, over which there is no permanent flow separation. Shear stress and turbulence above natural bedforms are higher than above a flat bed but much lower than over the often assumed 30° lee side angle.

  9. Influence of digestive morphology on resource partitioning in Amazonian ungulates.

    PubMed

    Bodmer, Richard E

    1991-01-01

    Resource partitioning of diet and habitat use was studied in the entire Amazonian ungulate community of Northeastern Peru, which comprises the red brocket deer (Mazama americana), grey brocket deer (M. gouazoubira), collared peccary (Tayassu tajacu), white-lipped peccary (T. pecari), and lowland tapir (Tapirus terrestris). Each ungulate species partitioned at least one type of resource from every other species. Digestive morphology had a greater influence on resource partitioning of diet than body size. Neither digestive morphology nor body size were related to segregation of habitats. However, species with similar diets partitioned habitats, whereas species with different diets often used the same type of forest. Increases in habitat breadth of ungulates were positively correlated with increases in dietary breadth.

  10. [Etiology of bruxism: morphological, pathophysiological and psychological factors].

    PubMed

    Lobbezoo, F; Naeije, M

    2000-07-01

    Bruxism is a controversial phenomenon, but there is consensus about the multifactorial nature of the etiology. Besides peripheral (morphological) factors, central (pathophysiological and psychological) factors can be distinguished. In the past, morphological factors, like occlusal discrepancies and the anatomy of the bony structures of the orofacial region, have been considered the main causative factors for bruxism. Nowadays, these factors play only a minor role, if any. Recent focus is more on the pathophysiological factors. For example, bruxism has been suggested to be part of a sleep arousal response. In addition, bruxism appears to be modulated by various neurotransmitters in the central nervous system. More specifically, disturbances in the central dopaminergic system have been linked to bruxism. Further, factors like smoking, alcohol, drugs, diseases, and trauma may be involved in the bruxism etiology. Psychological factors like stress and personality are frequently mentioned in relation to bruxism as well, but research shows controversial results. Taken all evidence together, bruxism appears to be mainly regulated centrally, not peripherally.

  11. Dynamic and reversible surface topography influences cell morphology.

    PubMed

    Kiang, Jennifer D; Wen, Jessica H; del Álamo, Juan C; Engler, Adam J

    2013-08-01

    Microscale and nanoscale surface topography changes can influence cell functions, including morphology. Although in vitro responses to static topography are novel, cells in vivo constantly remodel topography. To better understand how cells respond to changes in topography over time, we developed a soft polyacrylamide hydrogel with magnetic nickel microwires randomly oriented in the surface of the material. Varying the magnetic field around the microwires reversibly induced their alignment with the direction of the field, causing the smooth hydrogel surface to develop small wrinkles; changes in surface roughness, ΔRRMS , ranged from 0.05 to 0.70 μm and could be oscillated without hydrogel creep. Vascular smooth muscle cell morphology was assessed when exposed to acute and dynamic topography changes. Area and shape changes occurred when an acute topographical change was imposed for substrates exceeding roughness of 0.2 μm, but longer-term oscillating topography did not produce significant changes in morphology irrespective of wire stiffness. These data imply that cells may be able to use topography changes to transmit signals as they respond immediately to changes in roughness.

  12. Factors influencing breath ammonia determination.

    PubMed

    Solga, Steven F; Mudalel, Matthew; Spacek, Lisa A; Lewicki, Rafal; Tittel, Frank; Loccioni, Claudio; Russo, Adolfo; Risby, Terence H

    2013-09-01

    Amongst volatile compounds (VCs) present in exhaled breath, ammonia has held great promise and yet it has confounded researchers due to its inherent reactivity. Herein we have evaluated various factors in both breath instrumentation and the breath collection process in an effort to reduce variability. We found that the temperature of breath sampler and breath sensor, mouth rinse pH, and mode of breathing to be important factors. The influence of the rinses is heavily dependent upon the pH of the rinse. The basic rinse (pH 8.0) caused a mean increase of the ammonia concentration by 410 ± 221 ppb. The neutral rinse (pH 7.0), slightly acidic rinse (pH 5.8), and acidic rinse (pH 2.5) caused a mean decrease of the ammonia concentration by 498 ± 355 ppb, 527 ± 198 ppb, and 596 ± 385 ppb, respectively. Mode of breathing (mouth-open versus mouth-closed) demonstrated itself to have a large impact on the rate of recovery of breath ammonia after a water rinse. Within 30 min, breath ammonia returned to 98 ± 16% that of the baseline with mouth open breathing, while mouth closed breathing allowed breath ammonia to return to 53 ± 14% of baseline. These results contribute to a growing body of literature that will improve reproducibly in ammonia and other VCs.

  13. Genetic diversity of seagrass seeds influences seedling morphology and biomass.

    PubMed

    Randall Hughes, A; Hanley, Torrance C; Schenck, Forest R; Hays, Cynthia G

    2016-12-01

    Genetic diversity can influence ecological processes throughout ontogeny, yet whether diversity at early life history stages is important in long-lived taxa with overlapping generations is unclear. Seagrass systems provide some of the best evidence for the ecological effects of genetic diversity among adult shoots, but we do not know if the genetic diversity of seeds and seedlings also influences seagrass ecology. We tested the effects of seagrass (Zostera marina) seed diversity and relatedness on germination success, seedling morphology, and seedling production by comparing experimental assemblages of seeds collected from single reproductive shoots ("monocultures") to assemblages of seeds collected from multiple reproductive shoots ("polycultures"). There was no difference in seedling emergence, yet seedlings from polycultures had larger shoots above and below ground than seedlings from monocultures at the end of the 1-yr experiment. Genetic relatedness of the seedlings predicted some aspects of shoot morphology, with more leaves and longer roots and shoots at intermediate levels of relatedness, regardless of seed diversity. Our results suggest that studies of only adult stages may underestimate the importance of genetic diversity if the benefits at early life history stages continue to accrue throughout the life cycle.

  14. Influence of engineering variables upon the morphology of filamentous molds

    SciTech Connect

    Van Suijdam, J.C.; Metz, B.

    1981-01-01

    A model has been described for the influence of growth rate and shear stresses in the fermentor upon the morphology of filamentous molds. The main concept of this model is the dynamic equilibrium between growth and breakup of the hyphae. The latter has been approached according to well-known engineering theories for dispersion of physical systems. Experiments to verify the model with a strain of Tenicillium chrysogenum in batch and continuous culture revealed that the length of the mycelial particles increased with increasing' growth rate and decreased with increasing power input per unit mass in the fermentor. Although this was qualitatively in agreement with the presented model, quantitatively the model had to be rejected. Variation of the tensile strength of the hyphae with age and culturing conditions could have been one of the causes of disagreement. Oxygen tension, varied independently from stirrer speed, in the range of 12-300 mm Hg was shown to have no influence upon the morphology. With respect to the question of possibly using high-energy inputs in industrial mold fermentation in order to decrease hyphal length and suspension viscosity, it was concluded that this is of little practical value. A substantial decrease in hyphal length requires an enormous increase in energy input.

  15. Swimming efficiency and the influence of morphology on swimming costs in fishes.

    PubMed

    Ohlberger, J; Staaks, G; Hölker, F

    2006-01-01

    Swimming performance is considered a main character determining survival in many aquatic animals. Body morphology highly influences the energetic costs and efficiency of swimming and sets general limits on a species capacity to use habitats and foods. For two cyprinid fishes with different morphological characteristics, carp (Cyprinus carpio L.) and roach (Rutilus rutilus (L.)), optimum swimming speeds (U(mc)) as well as total and net costs of transport (COT, NCOT) were determined to evaluate differences in their swimming efficiency. Costs of transport and optimum speeds proved to be allometric functions of fish mass. NCOT was higher but U(mc) was lower in carp, indicating a lower swimming efficiency compared to roach. The differences in swimming costs are attributed to the different ecological demands of the species and could partly be explained by their morphological characteristics. Body fineness ratios were used to quantify the influence of body shape on activity costs. This factor proved to be significantly different between the species, indicating a better streamlining in roach with values closer to the optimum body form for efficient swimming. Net swimming costs were directly related to fish morphology.

  16. Influence of changing carbonate chemistry on morphology and weight of coccoliths formed by Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    Bach, L. T.; Bauke, C.; Meier, K. J. S.; Riebesell, U.; Schulz, K. G.

    2012-05-01

    The coccolithophore Emiliania huxleyi is a marine phytoplankton species capable of forming small calcium carbonate scales (coccoliths) which cover the organic part of the cell. Calcification rates of E. huxleyi are known to be sensitive to changes in seawater carbonate chemistry. It is, however, not yet understood how these changes are reflected in the morphology of coccoliths. Here, we compare data on coccolith size, weight, and malformation from a~set of five experiments with a large diversity of carbonate chemistry conditions. This diversity allows distinguishing the influence of individual carbonate chemistry parameters such as carbon dioxide (CO2), bicarbonate (HCO3-), carbonate (CO32-), and protons (H+) on the measured parameters. Measurements of fine-scale morphological structures reveal an increase of coccolith malformation with decreasing pH suggesting that H+ is the major factor causing malformations. Coccolith distal shield area varies from about 5 to 11 μm2. Changes in size seem to be mainly induced by varying [HCO3-] and [H+] although influence of [CO32-] cannot be entirely ruled out. Changes in coccolith weight were proportional to changes in size. Increasing CaCO3 production rates are reflected in an increase in coccolith weight and an increase of the number of coccoliths formed per unit time. The combined investigation of morphological features and coccolith production rates presented in this study may help to interpret data derived from sediment cores, where coccolith morphology is used to reconstruct calcification rates in the water column.

  17. The influence of morphology on excitons in single conjugated molecules

    NASA Astrophysics Data System (ADS)

    Thiessen, Alexander

    The electronic properties of pi-conjugated molecules are strongly related to their molecular shape and morphology of assembly in three-dimensional space. Understanding the various structure-property relationships is relevant to the applications of these materials in optoelectronic devices such as organic light-emitting diodes, field effect transistors and photovoltaic cells. The fact that conjugated systems interact with visible light opens these materials to a plethora of noninvasive spectroscopic investigation techniques. In this work, electronic properties of different pi-conjugated systems are studied spectroscopically on the ensemble and the single molecule levels. Single molecule spectroscopy is advantageous in that it allows the investigation of the individual nuclear building blocks that contribute to the properties of the ensemble. Additionally, transient photoluminescence spectroscopy methods can provide useful insight into the temporal evolution of the emissive states. In combination with these methods, novel pi-conjugated model molecules are used to probe processes related to exciton dynamics. For the first time, the spatial localization of excited states is probed experimentally in a molecule with a circular chromophoric structure. In addition, a set of model molecules with different geometries is employed to study exciton relaxation in pi-conjugated systems. The molecular morphology is utilized to distinguish between processes such as nuclear reorganization and torsional relaxation. Furthermore, single molecule spectroscopy is used to study the electronic structure of individual polymer chains in the photovoltaic cell material poly-(3-hexylthiophene). Optical spectra of this polymer are known to change with the morphology of the bulk film. Single molecule studies reveal that individual polymer chains exhibit similar behavior and indicate that spectral diversity is an intrinsic property of single P3HT molecules. The main results of this work are the

  18. Factors that Influence Participation in Online Learning

    ERIC Educational Resources Information Center

    Vonderwell, Selma; Zachariah, Sajit

    2005-01-01

    This study explored what factors influenced learner participation in two sections of a graduate online course at a Midwestern university. Findings indicated that online learner participation and patterns of participation are influenced by the following factors: technology and interface characteristics, content area experience, student roles and…

  19. Factors influencing dust suppressant effectiveness

    SciTech Connect

    Copeland, C.R.; Eisele, T.C.; Chesney, D.J.; Kawatra, S.K.

    2008-11-15

    Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

  20. Morphological influence of cellulose nanoparticles (CNs) from cottonseed hulls on rheological properties of polyvinyl alcohol/CN suspensions.

    PubMed

    Zhou, Ling; He, Hui; Li, Mei-Chun; Song, Kunlin; Cheng, H N; Wu, Qinglin

    2016-11-20

    The present work describes the isolation of cellulose nanoparticles (CNs) with different morphologies and their influence on rheological properties of CN and CN-poly (vinyl alcohol) (PVA) suspensions. Cottonseed hulls were used for the first time to extract three types of CNs, including fibrous cellulose nanofibers, rod-like cellulose nanocrystals and spherical cellulose nanoparticles through mechanical and chemical methods. Rheology results showed that the rheological behavior of the CN suspensions was strongly dependent on CN concentration and particle morphology. For PVA/CN systems, concentration of PVA/CN suspension, morphology of CNs, and weight ratio of CN to PVA were three main factors that influenced their rheology behaviors. This research reveals the importance of CN morphology and composition concentration on the rheological properties of PVA/CN, providing new insight in preparing high performance hydrogels, fibers and films base on PVA/CN suspension systems.

  1. The parameters influencing the morphology of poly(ɛ-caprolactone) microspheres and the resulting release of encapsulated drugs.

    PubMed

    Bile, Jessica; Bolzinger, Marie-Alexandrine; Vigne, Charlène; Boyron, Olivier; Valour, Jean-Pierre; Fessi, Hatem; Chevalier, Yves

    2015-10-15

    Polymer microparticles used for drug encapsulation and delivery have various surface morphologies depending on the type of formulation ingredients and parameters of the manufacture process. This works aims at investigating the critical parameters governing the morphology of microparticles and to underline the influence of their surface state on the drug release. The classical fabrication process by the "emulsion-solvent evaporation" is addressed using poly(ɛ-caprolactone) as the polymer and methylene chloride as the volatile organic solvent. The typical surfactants poly(vinyl alcohol) and polysorbate 80 have been considered. Scanning electron microscopy observations showed the various surface morphologies mainly depending on the stirring rate, the viscosity of the oil phase and by the presence of inappropriate surfactants. Because of arrested coalescence during solvent evaporation, the evaporation of the organic solvent causing particles hardening is the most important parameter that controls the morphology. Indeed, slow evaporation allows partial coalescence of the soft particles swollen by the organic solvent, whereas the particles morphology is frozen rapidly upon fast evaporation, thus preventing damaged surface states. Moreover, an effective stabilizing system for the primary emulsion is also a determining factor to control the final morphology. The morphology of the particles has a definite influence on the drug delivery of cholecalciferol. The surface morphology should be taken into consideration in the design of polymer microparticles because it allows a control over the drug release kinetics.

  2. Factors influencing perceived angular velocity

    NASA Technical Reports Server (NTRS)

    Kaiser, Mary K.; Calderone, Jack B.

    1991-01-01

    Angular velocity perception is examined for rotations both in depth and in the image plane and the influence of several object properties on this motion parameter is explored. Two major object properties are considered, namely, texture density which determines the rate of edge transitions for rotations in depth, i.e., the number of texture elements that pass an object's boundary per unit of time, and object size which determines the tangential linear velocities and 2D image velocities of texture elements for a given angular velocity. Results of experiments show that edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities had an impact on perceived angular velocity; this bias was associated with 2D image velocity rather than 3D tangential velocity. Despite these biases judgements were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter appeared to be good for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

  3. Predation risk influences adaptive morphological variation in fish populations.

    PubMed

    Eklöv, Peter; Svanbäck, Richard

    2006-03-01

    Predators can cause a shift in both density and frequency of a prey phenotype that may lead to phenotypic divergence through natural selection. What is less investigated is that predators have a variety of indirect effects on prey that could potentially have large evolutionary responses. We conducted a pond experiment to test whether differences in predation risk in different habitats caused shifts in behavior of prey that, in turn, would affect their morphology. We also tested whether the experimental data could explain the morphological variation of perch in the natural environment. In the experiment, predators caused the prey fish to shift to the habitat with the lower predation risk. The prey specialized on habitat-specific resources, and there was a strong correlation between diet of the prey fish and morphological variation, suggesting that resource specialization ultimately affected the morphology. The lack of differences in competition and mortality suggest that the morphological variation among prey was induced by differences in predation risk among habitats. The field study demonstrated that there are differences in growth related to morphology of perch in two different habitats. Thus, a trade-off between foraging and predator avoidance could be responsible for adaptive morphological variation of young perch.

  4. Influence of Copolymer Composition on Morphology Development in Blends

    NASA Astrophysics Data System (ADS)

    Krishanmoorthy, Jayaraman

    2005-03-01

    Blends involving a crystallizable polyester [poly(hexamethylene adipate) (PHMA)] with an amorphous polyether has been studied. These systems have hydroxyl end groups which can react with diisocyanate in the presence of nucleophilic catalysts. These functionalized (isocyanate-terminated) polymer blends form the fundamental structure of polyurethanes. These prepolymers can then be cured at a later stage due to ambient water molecules. Thus the migration of water molecules through the morphology formed needs to be understood well. The morphology development (i.e. phase separation occurring concurrently with crystallization) of nascent polymer blends has been characterized. The morphology of functionalized polymers exhibit very different kinetics due to the presence of the small amount of copolymers formed. The ultimate morphology formed can be ``tuned'' by varying blend composition and crystallization conditions. The structures of prepolymers will be reported. The presence of this copolymer can significantly alter the structural transformation in either binary or ternary blends.

  5. Environmental influence on the evolution of morphological complexity in machines.

    PubMed

    Auerbach, Joshua E; Bongard, Josh C

    2014-01-01

    Whether, when, how, and why increased complexity evolves in biological populations is a longstanding open question. In this work we combine a recently developed method for evolving virtual organisms with an information-theoretic metric of morphological complexity in order to investigate how the complexity of morphologies, which are evolved for locomotion, varies across different environments. We first demonstrate that selection for locomotion results in the evolution of organisms with morphologies that increase in complexity over evolutionary time beyond what would be expected due to random chance. This provides evidence that the increase in complexity observed is a result of a driven rather than a passive trend. In subsequent experiments we demonstrate that morphologies having greater complexity evolve in complex environments, when compared to a simple environment when a cost of complexity is imposed. This suggests that in some niches, evolution may act to complexify the body plans of organisms while in other niches selection favors simpler body plans.

  6. Influence of changing carbonate chemistry on morphology and weight of coccoliths formed by Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    Bach, L. T.; Bauke, C.; Meier, K. J. S.; Riebesell, U.; Schulz, K. G.

    2012-08-01

    The coccolithophore Emiliania huxleyi is a marine phytoplankton species capable of forming small calcium carbonate scales (coccoliths) which cover the organic part of the cell. Calcification rates of E. huxleyi are known to be sensitive to changes in seawater carbonate chemistry. It has, however, not yet been clearly determined how these changes are reflected in size and weight of individual coccoliths and which specific parameter(s) of the carbonate system drive morphological modifications. Here, we compare data on coccolith size, weight, and malformation from a set of five experiments with a large diversity of carbonate chemistry conditions. This diversity allows distinguishing the influence of individual carbonate chemistry parameters such as carbon dioxide (CO2), bicarbonate (HCO3-), carbonate ion (CO32-), and protons (H+) on the measured parameters. Measurements of fine-scale morphological structures reveal an increase of coccolith malformation with decreasing pH suggesting that H+ is the major factor causing malformations. Coccolith distal shield area varies from about 5 to 11 μm2. Changes in size seem to be mainly induced by varying [HCO3-] and [H+] although influence of [CO32-] cannot be entirely ruled out. Changes in coccolith weight were proportional to changes in size. Increasing CaCO3 production rates are reflected in an increase in coccolith weight and an increase of the number of coccoliths formed per unit time. The combined investigation of morphological features and coccolith production rates presented in this study may help to interpret data derived from sediment cores, where coccolith morphology is used to reconstruct calcification rates in the water column.

  7. What Factors Influence Wind Perceptions

    NASA Astrophysics Data System (ADS)

    Stein, Tatiana

    Over the last decade, wind power has emerged as a possible source of energy and has attracted the attention of homeowners and policy makers worldwide. Many technological hurdles have been overcome in the last few years that make this technology feasible and economical. The United States has added more wind power than any other type of electric generation in 2012. Depending on the location, wind resources have shown to have the potential to offer 20% of the nation's electricity; a single, large wind turbine has the capacity to produce enough electricity to power 350 homes. Throughout the development of wind turbines, however, energy companies have seen significant public opposition towards the tall white structures. The purpose of this research was to measure peoples' perceptions on wind turbine development throughout their growth, from proposal to existing phase. Three hypotheses were developed based on the participant's political affiliation, proximity and knowledge of wind turbines. To validate these hypotheses, participants were asked an array of questions regarding their perception on economic, environmental, and social impacts of wind turbines with an online service called Amazon Mechanical Turk. The responses were from residents living in the United States and required them to provide their zip code for subsequent analysis. The analysis from the data obtained suggests that participants are favorable towards wind turbine development and would be supportive of using the technology in their community. Political affiliation and proximity to the nearest wind turbine in any phase of development (proposal, construction, existing) were also analyzed to determine if they had an effect on a person's overall perception on wind turbines and their technology. From the analysis, political affiliation was seen to be an indirect factor to understanding favorability towards wind turbines; the more liberal you are, the more supportive you will be towards renewable energy use

  8. Influence of Alluvial Morphology on Upscaled Hydraulic Conductivity.

    PubMed

    Jha, Sanjeev Kumar; Mariethoz, Gregoire; Mathews, George; Vial, John; Kelly, Bryce F J

    2016-05-01

    The hydraulic conductivity of aquifers is a key parameter controlling the interactions between resource exploitation activities, such as unconventional gas production and natural groundwater systems. Furthermore, this parameter is often poorly constrained by typical data used for regional groundwater modeling and calibration studies performed as part of impact assessments. In this study, a systematic investigation is performed to understand the correspondence between the lithological descriptions of channel-type formation and the bulk effective hydraulic conductivities at a larger scale (Kxeff , Kyeff , and Kzeff in the direction of channel cross section, along the channel and in the vertical directions, respectively). This will inform decisions on what additional data gathering and modeling of the geological system can be performed to allow the critical bulk properties to be more accurately predicted. The systems studied are conceptualized as stacked meandering channels formed in an alluvial plain, and are represented as two facies. Such systems are often studied using very detailed numerical models. The main factors that may influence Kxeff , Kyeff , and Kzeff are the proportion of the facies representing connected channels, the aspect ratio of the channels, and the difference in hydraulic conductivity between facies. Our results show that in most cases, Kzeff is only weakly dependent on the orientations of channelized structures, with the main effects coming from channel aspect ratio and facies proportion.

  9. Imitation, genetic lineages, and time influenced the morphological evolution of the violin.

    PubMed

    Chitwood, Daniel H

    2014-01-01

    Violin design has been in flux since the production of the first instruments in 16th century Italy. Numerous innovations have improved the acoustical properties and playability of violins. Yet, other attributes of the violin affect its performance less, and with fewer constraints, are potentially more sensitive to historical vagaries unrelated to quality. Although the coarse shape of violins is integral to their design, details of the body outline can vary without significantly compromising sound quality. What can violin shapes tell us about their makers and history, including the degree that luthiers have influenced each other and the evolution of complex morphologies over time? Here, I provide an analysis of morphological evolution in the violin family, sampling the body shapes of over 9,000 instruments over 400 years of history. Specific shape attributes, which discriminate instruments produced by different luthiers, strongly correlate with historical time. Linear discriminant analysis reveals luthiers who likely copied the outlines of their instruments from others, which historical accounts corroborate. Clustering of averaged violin shapes places luthiers into four major groups, demonstrating a handful of discrete shapes predominate in most instruments. Violin shapes originating from multi-generational luthier families tend to cluster together, and familial origin is a significant explanatory factor of violin shape. Together, the analysis of four centuries of violin shapes demonstrates not only the influence of history and time leading to the modern violin, but widespread imitation and the transmission of design by human relatedness.

  10. Imitation, Genetic Lineages, and Time Influenced the Morphological Evolution of the Violin

    PubMed Central

    Chitwood, Daniel H.

    2014-01-01

    Violin design has been in flux since the production of the first instruments in 16th century Italy. Numerous innovations have improved the acoustical properties and playability of violins. Yet, other attributes of the violin affect its performance less, and with fewer constraints, are potentially more sensitive to historical vagaries unrelated to quality. Although the coarse shape of violins is integral to their design, details of the body outline can vary without significantly compromising sound quality. What can violin shapes tell us about their makers and history, including the degree that luthiers have influenced each other and the evolution of complex morphologies over time? Here, I provide an analysis of morphological evolution in the violin family, sampling the body shapes of over 9,000 instruments over 400 years of history. Specific shape attributes, which discriminate instruments produced by different luthiers, strongly correlate with historical time. Linear discriminant analysis reveals luthiers who likely copied the outlines of their instruments from others, which historical accounts corroborate. Clustering of averaged violin shapes places luthiers into four major groups, demonstrating a handful of discrete shapes predominate in most instruments. Violin shapes originating from multi-generational luthier families tend to cluster together, and familial origin is a significant explanatory factor of violin shape. Together, the analysis of four centuries of violin shapes demonstrates not only the influence of history and time leading to the modern violin, but widespread imitation and the transmission of design by human relatedness. PMID:25295734

  11. Influencing factors in MMR immunisation decision making.

    PubMed

    Hill, Marie C; Cox, Carol L

    Immunisation decision making is not a straightforward process for parents. Many factors influence parental decision making on whether they immunise their child with the measles, mumps and rubella (MMR) vaccine. The feasibility study described in this article provides insight into influencing factors associated with decisions regarding the immunisation of children by parents. The study findings suggest that the practice nurse is a credible source of information for parents seeking informed decision making. At a time when the incidence of measles and mumps is rising in the UK, the provision of appropriate information by the practice nurse has the potential to increase uptake of the MMR vaccine.

  12. Factors influencing households' participation in recycling.

    PubMed

    Vicente, Paula; Reis, Elizabeth

    2008-04-01

    The success of a recycling programme depends on the active and sustained participation of citizens in the correct separation and collection of recyclable waste. An effective study of strategies aimed at augmenting people's involvement in recycling involves understanding which factors influence the decision to co-operate with a recycling programme. This research investigates the influence of attitudes, incentives, presence of children in household and information through direct media, on households' participation in recycling. The results suggest that positive attitudes toward recycling and information are important factors in explaining recycling participation. Some guidelines that may be considered in future communication and intervention strategies designed to promote recycling participation are discussed.

  13. Factors Influencing Job Satisfaction among Army Chaplains

    DTIC Science & Technology

    1976-05-20

    or 20 MAY 1976 STUDY ’ PROJECT FACTORS INFLUENCING JOB SATISFACTION AMONG ARMY CHAPLAINS BY CHAPLAIN(COLONEL) KERMIT D. JOHNSON US ARMY WAR...job •atUfaction among US kxmy chaplain« it b«aad CO • mail aurvay raaponao of 998 chap Ulna out of 1411 in tha Army chaplaincy. Factors which...chaplaincy, and cosseand. Certain professional Irritants were singled out. By means of demographic information, comparisons were made as to how

  14. Differential Influence of Clonal Integration on Morphological and Growth Responses to Light in Two Invasive Herbs

    PubMed Central

    Xu, Cheng-Yuan; Schooler, Shon S.; Van Klinken, Rieks D.

    2012-01-01

    Background and aims In contrast to seeds, high sensitivity of vegetative fragments to unfavourable environments may limit the expansion of clonal invasive plants. However, clonal integration promotes the establishment of propagules in less suitable habitats and may facilitate the expansion of clonal invaders into intact native communities. Here, we examine the influence of clonal integration on the morphology and growth of ramets in two invasive plants, Alternanthera philoxeroides and Phyla canescens, under varying light conditions. Methods In a greenhouse experiment, branches, connected ramets and severed ramets of the same mother plant were exposed under full sun and 85% shade and their morphological and growth responses were assessed. Key results The influence of clonal integration on the light reaction norm (connection×light interaction) of daughter ramets was species-specific. For A. philoxeroides, clonal integration evened out the light response (total biomass, leaf mass per area, and stem number, diameter and length) displayed in severed ramets, but these connection×light interactions were largely absent for P. canescens. Nevertheless, for both species, clonal integration overwhelmed light effect in promoting the growth of juvenile ramets during early development. Also, vertical growth, as an apparent shade acclimation response, was more prevalent in severed ramets than in connected ramets. Finally, unrooted branches displayed smaller organ size and slower growth than connected ramets, but the pattern of light reaction was similar, suggesting mother plants invest in daughter ramets prior to their own branches. Conclusions Clonal integration modifies light reaction norms of morphological and growth traits in a species-specific manner for A. philoxeroides and P. canescens, but it improves the establishment of juvenile ramets of both species in light-limiting environments by promoting their growth during early development. This factor may be partially

  15. Factors Influencing High School Students' Career Aspirations

    ERIC Educational Resources Information Center

    Tang, Mei; Pan, Wei; Newmeyer, Mark D.

    2008-01-01

    This article explores the factors influencing high school students' career aspirations with a study analyzing 141 high school students. The Social Cognitive Career Development Model was utilized to examine the interactive relationships among learning experiences, career self-efficacy, outcome expectations, career interests, and career choices. The…

  16. Factors Influencing Employee Learning in Small Businesses

    ERIC Educational Resources Information Center

    Coetzer, Alan; Perry, Martin

    2008-01-01

    Purpose: The purpose of this research is to identify key factors influencing employee learning from the perspective of owners/managers. Design/methodology/research: Data were gathered from owners/managers in a total of 27 small manufacturing and services firms through interviews and analysed using content analytic procedures. Findings: The…

  17. ESR (Electroslag Refining) Steel Deoxidation and Slag Practice - Influence on Inclusion Morphology,

    DTIC Science & Technology

    1984-01-01

    VICTORIA I REPORT MRL-R-915 ESR STEEL DEOXIDATION AND SLAG PRACTICE - INFLUENCE ON INCLUSION MORPHOLOGY G.M. Weston and R.C. Andrew THE UNITED...Commonweallh of Austaii eJA3UAY, 1984 DEPARTMENT OF DEFENCE MATERIALS RESEARCH LABORATORIES REPORT MRL-R-915 ESR STEEL DEOXIDATION AND SLAG PRACTICE...TLE ESR STEEL DEOXIDATION AND SLAG PRACTICE - INFLUENCE ON INCLUSION MORPHOLOGY AUTHOR(S) CORPORATE AUTHOR Materials Research Laboratories G.M. Weston

  18. Social Factors Influencing Child Health in Ghana

    PubMed Central

    Quansah, Emmanuel; Ohene, Lilian Akorfa; Norman, Linda; Mireku, Michael Osei; Karikari, Thomas K.

    2016-01-01

    Objectives Social factors have profound effects on health. Children are especially vulnerable to social influences, particularly in their early years. Adverse social exposures in childhood can lead to chronic disorders later in life. Here, we sought to identify and evaluate the impact of social factors on child health in Ghana. As Ghana is unlikely to achieve the Millennium Development Goals’ target of reducing child mortality by two-thirds between 1990 and 2015, we deemed it necessary to identify social determinants that might have contributed to the non-realisation of this goal. Methods ScienceDirect, PubMed, MEDLINE via EBSCO and Google Scholar were searched for published articles reporting on the influence of social factors on child health in Ghana. After screening the 98 articles identified, 34 of them that met our inclusion criteria were selected for qualitative review. Results Major social factors influencing child health in the country include maternal education, rural-urban disparities (place of residence), family income (wealth/poverty) and high dependency (multiparousity). These factors are associated with child mortality, nutritional status of children, completion of immunisation programmes, health-seeking behaviour and hygiene practices. Conclusions Several social factors influence child health outcomes in Ghana. Developing more effective responses to these social determinants would require sustainable efforts from all stakeholders including the Government, healthcare providers and families. We recommend the development of interventions that would support families through direct social support initiatives aimed at alleviating poverty and inequality, and indirect approaches targeted at eliminating the dependence of poor health outcomes on social factors. Importantly, the expansion of quality free education interventions to improve would-be-mother’s health knowledge is emphasised. PMID:26745277

  19. Factors that influence women's dispositions toward science

    NASA Astrophysics Data System (ADS)

    Atria, Catherine Graczyk

    Females have been underrepresented in the study of science and science careers for decades although advancements have been made in closing this gender gap, the gap persists particularly in the physical sciences. Variables which influence a woman's desire to pursue and maintain a science course of study and career must be discovered. The United States lags behind other industrialized countries in the fields of science, math, and engineering. Females comprise an estimated half of the population; their potential contributions cannot be ignored or overlooked. This retrospective research study explores the personal experiences of ten women enrolled in science majors, with science related career plans. The goal of this study is to describe the factors that influence the participants' interest in science. The findings, the effect of science coursework, science teachers' personality and manner, other influential educational personnel, role models and mentors, external influences exclusive of school, parental influence, locus of control and positive attitudes toward science confirm what other researchers have found.

  20. The influence of morphology on charge transport/recombination dynamics in planar perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Yu, Man; Wang, Yi; Wang, Hao-Yi; Han, Jun; Qin, Yujun; Zhang, Jian-Ping; Ai, Xi-Cheng

    2016-10-01

    The photovoltaic performance of planar perovskite solar cell is significantly influenced by the morphology of perovskite film. In this work, five kinds of devices with different perovskite film morphologies were prepared by varying the concentration of CH3NH3Cl in precursor solutions. We found that best morphology of perovskite film results in the excellent photovoltaic performance with an average efficiency of 15.52% and a champion efficiency of 16.38%. Transient photovoltage and photocurrent measurements are performed to elucidate the mechanism of photoelectric conversion processes, which shows that the charge recombination is effectively suppressed and the charge transport is obviously promoted by optimized morphology.

  1. Thin Ag films. Influence of substrate and postdeposition treatment on morphology and optical properties

    SciTech Connect

    Roark, S.E.; Rowlen, K.L. )

    1994-01-15

    In an effort to understand the experimental parameters that influence thin metal film morphology and optical characteristics, thin Ag films are examined with a combination of atomic force microscopy (AFM), optical absorption, and surface-enhanced Raman spectroscopy (SERS). The morphology of 5 nm of Ag vapor deposited onto glass, derivatized glass, Formvar-coated glass, and mica is explored. The substrate is found to have a large effect on both Ag film surface morphology and optical properties. In addition, micrographs of a Ag film before and after exposure to solvent suggest solvent-induced morphological changes. 32 refs., 8 figs., 5 tabs.

  2. Influence of urban morphology on total noise pollution: multifractal description.

    PubMed

    Ariza-Villaverde, Ana B; Jiménez-Hornero, Francisco J; Gutiérrez De Ravé, Eduardo

    2014-02-15

    Exposure to ambient noise levels above 65 dB can cause public health problems. The spatial distribution of this kind of pollution is linked to various elements which make up the urban form, such as construction density, the existence of open spaces and the shape and physical position of buildings. Since urban morphology displays multifractal behaviour, the present research studies for the first time the relationship between total noise pollution and urban features, such as street width and building height by means of a joint multifractal spectrum in two neighbourhoods of the city of Cordoba (Andalusia, Spain). According to the results, the joint multifractal spectrum reveals a positive correlation between the total noise pollution and the street width to building height ratio, this being more evident when urban morphology is regular. The information provided by the multifractal analysis completes the description obtained by using urban indexes and landscape metrics and might be useful for urban planning once the linkage between both frameworks has been done.

  3. Influence of organizational factors on safety

    SciTech Connect

    Haber, S.B.; Metlay, D.S.; Crouch, D.A.

    1990-01-01

    There is a need for a better understanding of exactly how organizational management factors at a nuclear power plant (NPP) affect plant safety performance, either directly or indirectly, and how these factors might be observed, measured, and evaluated. The purpose of this research project is to respond to that need by developing a general methodology for characterizing these organizational and management factors, systematically collecting information on their status and integrating that information into various types of evaluative activities. Research to date has included the development of the Nuclear Organization and Management Analysis Concept (NOMAC) of a NPP, the identification of key organizational and management factors, and the identification of the methods for systematically measuring and analyzing the influence of these factors on performance. Most recently, two field studies, one at a fossil fuel plant and the other at a NPP, were conducted using the developed methodology. Results are presented from both studies highlighting the acceptability, practicality, and usefulness of the methods used to assess the influence of various organizational and management factors including culture, communication, decision-making, standardization, and oversight. 6 refs., 3 figs., 1 tab.

  4. Reach-Scale Hydraulic Influence on Sediment Dynamics and Morphological Development in a Bedrock Influenced River

    NASA Astrophysics Data System (ADS)

    Entwistle, N. S.; Heritage, G. L.; Milan, D. J.; Tooth, S.

    2014-12-01

    Many large rivers in southern Africa are characterised by a macro-channel cut 10 - 20 m into the ancient planation surface. This has resulted in a variable channel morphology strongly influenced by bedrock outcrops. The influence of bedrock upon flow hydraulics and sediment transport often results in a repeat sequence of alluvial channel types behind bedrock obstructions. This study investigates the hydraulic controls on channel type sequencing on the Sabie River, which drains a 6500 km2 semi-arid catchment of the Lowveld of South Africa and Mozambique. Aerial LIDAR data within the Kruger National Park was interrogated to isolate a bedrock influenced anastomosing reach, together with its associated alluvial sequences up- and downstream. These data were used to create a 2m DEM and a 2D flow model (JFLOW) was used to simulate a sequence of flows from 20 m3s-1 to 5000 m3s-1, with spatial data on water surface, flow depth and channel velocity extracted from the model. Water surface data revealed the strong gradient control exerted by the bedrock influenced anastomosed channel, creating hydraulic conditions suitable for deposition upstream and restricting sedimentation downstream. Steepening of the gradient through the anastomosing reach resulted in altered hydraulics and a changed pattern of sedimentation. At moderate discharges, flow is distributed efficiently across numerous interconnected channels, over low berms and islands, promoting sedimentation. Similarly the backwater effect encourages deposition of fine sediments upstream to create and maintain the alluvial sequence. Under higher flows, water levels rise significantly in the confined upstream reach and shear stress exceeds the threshold necessary to strip stored sediment. In contrast, conditions within the anastomosed reach remain less energetic due to the continued effect of flow distribution. Under extreme flow conditions the bedrock influence is drowned out resulting in dramatically increased energy levels

  5. Natural selection on floral morphology can be influenced by climate.

    PubMed

    Campbell, Diane R; Powers, John M

    2015-06-07

    Climate has the potential to influence evolution, but how it influences the strength or direction of natural selection is largely unknown. We quantified the strength of selection on four floral traits of the subalpine herb Ipomopsis sp. in 10 years that differed in precipitation, causing extreme temporal variation in the date of snowmelt in the Colorado Rocky Mountains. The chosen floral traits were under selection by hummingbird and hawkmoth pollinators, with hawkmoth abundance highly variable across years. Selection for flower length showed environmental sensitivity, with stronger selection in years with later snowmelt, as higher water resources can allow translation of pollination success into fitness based on seed production. Selection on corolla width also varied across years, favouring narrower corolla tubes in two unusual years with hawkmoths, and wider corollas in another late snowmelt year. Our results illustrate how changes in climate could alter natural selection even when the primary selective agent is not directly influenced.

  6. Natural selection on floral morphology can be influenced by climate

    PubMed Central

    Campbell, Diane R.; Powers, John M.

    2015-01-01

    Climate has the potential to influence evolution, but how it influences the strength or direction of natural selection is largely unknown. We quantified the strength of selection on four floral traits of the subalpine herb Ipomopsis sp. in 10 years that differed in precipitation, causing extreme temporal variation in the date of snowmelt in the Colorado Rocky Mountains. The chosen floral traits were under selection by hummingbird and hawkmoth pollinators, with hawkmoth abundance highly variable across years. Selection for flower length showed environmental sensitivity, with stronger selection in years with later snowmelt, as higher water resources can allow translation of pollination success into fitness based on seed production. Selection on corolla width also varied across years, favouring narrower corolla tubes in two unusual years with hawkmoths, and wider corollas in another late snowmelt year. Our results illustrate how changes in climate could alter natural selection even when the primary selective agent is not directly influenced. PMID:25972465

  7. Political and economic factors influencing contraceptive uptake.

    PubMed

    Sai, F T

    1993-01-01

    International, national and local level politics influence the uptake of contraception through consensuses, laws, financial and moral support or the creation of an enabling atmosphere. Opposition to contraception generally comes from some churches and groups opposed to particular technologies. Socio-economic factors, particularly education, the health care system and the perceived or actual cost of fertility regulation as compared to benefits expected from children also powerfully influence contraceptive use. For many poor women in developing countries their powerlessness in relation to their male partners is an important obstacle.

  8. Influencing factor on the prognosis of arthrocentesis

    PubMed Central

    Kim, Yoon Ho; Jeong, Tae Min; Pang, Kang Mi

    2014-01-01

    Objectives The purpose of this article is to evaluate factors influencing prognosis of arthrocentesis in patients with temporomandibular joint (TMJ) disorder. Materials and Methods The subjects included 145 patients treated with arthrocentesis at the Dental Center of Ajou University Hospital from 2011 to 2013 for the purpose of recovering mouth opening limitation (MOL) and pain relief. Prognosis of arthrocentesis was evaluated 1 month after the operation. Improvement on MOL was defined as an increase from below 30 mm (MOL ≤30 mm) to above 40 mm (MOL ≥40 mm), and pain relief was defined as when a group with TMJ pain with a visual analog scale (VAS) score of 4 or more (VAS ≥4) decreased to a score of 3 or more. The success of arthrocentesis was determined when either mouth opening improved or pain relief was fulfilled. To determine the factors influencing the success of arthrocentesis, the patients were classified by age, gender, diagnosis group (the anterior disc displacement without reduction group, the anterior disc displacement with reduction group, or other TMJ disorders group), time of onset and oral habits (clenching, bruxism) to investigate the correlations between these factors and prognosis. Results One hundred twenty out of 145 patients who underwent arthrocentesis (83.4%) were found to be successful. Among the influencing factors mentioned above, age, diagnosis and time of onset had no statistically significant correlation with the success of arthrocentesis. However, a group of patients in their fifties showed a lower success rate (ANOVA P=0.053) and the success rate of the group with oral habits was 71% (Pearson's chi-square test P=0.035). Conclusion From this study, we find that factors influencing the success of arthrocentesis include age and oral habits. We also conclude that arthrocentesis is effective in treating mouth opening symptoms and for pain relief. PMID:25247144

  9. Media formulation influences chemical effects on neuronal growth and morphology.

    PubMed

    Harrill, Joshua A; Robinette, Brian L; Freudenrich, Theresa M; Mundy, William R

    2015-06-01

    Screening for developmental neurotoxicity using in vitro, cell-based systems has been proposed as an efficient alternative to performing in vivo studies. One tool currently used for developmental neurotoxicity screening is automated high-content imaging of neuronal morphology. While high-content imaging (HCI) has been demonstrated to be useful in detection of potential developmental neurotoxicants, comparison of results between laboratories or assays can be complicated due to methodological differences. In order to determine whether high-content imaging-based developmental neurotoxicity assays can be affected by differences in media formulation, a systematic comparison of serum-supplemented (Dulbecco's modified Eagle's media (DMEM) + 10% serum) and serum-free (Neurobasal A + B27) culture media on neuronal morphology was performed using primary rat cortical neurons. Concentration-response assays for neuritogenesis, axon and dendrite outgrowth, and synaptogenesis were performed in each media type using chemicals with previously demonstrated effects. Marked qualitative and quantitative differences in the characteristics of neurons cultured in the two media types were observed, with increased neuronal growth and less basal cell death in Neurobasal A + B27. Media formulation also affected assay sensitivity and selectivity. Increases in assay sensitivity were observed in Neurobasal A + B27 media as compared to serum-supplemented DMEM. In some instances, a greater difference between effective concentrations for cell death and neurodevelopmental-specific endpoints was also observed in Neurobasal A + B27 media as compared to serum-supplemented DMEM. These data show that media formulation must be considered when comparing data for similar endpoints between studies. Neuronal culture maintained in Neurobasal A + B27 media had several features advantageous for HCI applications including less basal cell death, less cell clustering and neurite fasciculation, and a tendency

  10. Factors Affecting the Acquisition of Plural Morphology in Jordanian Arabic

    ERIC Educational Resources Information Center

    Albirini, Abdulkafi

    2015-01-01

    This study investigates the development of plural morphology in Jordanian Arab children, and explores the role of the predictability, transparency, productivity, and frequency of different plural forms in determining the trajectory that children follow in acquiring this complex inflectional system. The study also re-examines the development of the…

  11. Factors Influencing the Eicosanoids Synthesis In Vivo

    PubMed Central

    Kruszewski, Wiesław Janusz; Sobczak, Ewa

    2015-01-01

    External factors activate a sequence of reactions involving the reception, transduction, and transmission of signals to effector cells. There are two main phases of the body's reaction to harmful factors: the first aims to neutralize the harmful factor, while in the second the inflammatory process is reduced in size and resolved. Secondary messengers such as eicosanoids are active in both phases. The discovery of lipoxins and epi-lipoxins demonstrated that not all arachidonic acid (AA) derivatives have proinflammatory activity. It was also revealed that metabolites of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) such as resolvins, protectins, and maresins also take part in the resolution of inflammation. Knowledge of the above properties has stimulated several clinical trials on the influence of EPA and DHA supplementation on various diseases. However, the equivocal results of those trials prevent the formulation of guidelines on EPA and DHA supplementation. Prescription drugs are among the substances with the strongest influence on the profile and quantity of the synthesized eicosanoids. The lack of knowledge about their influence on the conversion of EPA and DHA into eicosanoids may lead to erroneous conclusions from clinical trials. PMID:25861641

  12. Factors influencing micronutrient bioavailability in biofortified crops.

    PubMed

    Bechoff, Aurélie; Dhuique-Mayer, Claudie

    2017-02-01

    Dietary and human factors have been found to be the major factors influencing the bioavailability of micronutrients, such as provitamin A carotenoid (pVAC), iron, and zinc, in biofortified crops. Dietary factors are related to food matrix structure and composition. Processing can improve pVAC bioavailability by disrupting the food matrix but can also result in carotenoid losses. By degrading antinutrients, such as phytate, processing can also enhance mineral bioavailability. In in vivo interventions, biofortified crops have been shown to be overall efficacious in reducing micronutrient deficiency, with bioconversion factors varying between 2.3:1 and 10.4:1 for trans-β-carotene and amounts of iron and zinc absorbed varying between 0.7 and 1.1 mg/day and 1.1 and 2.1 mg/day, respectively. Micronutrient bioavailability was dependent on the crop type and the presence of fat for pVACs and on antinutrients for minerals. In addition to dietary factors, human factors, such as inflammation and disease, can affect micronutrient status. Understanding the interactions between micronutrients is also essential, for example, the synergic effect of iron and pVACs or the competitive effect of iron and zinc. Future efficacy trials should consider human status and genetic polymorphisms linked to interindividual variations.

  13. Influence of sulfur in coals on char morphology and combustion. Technical report, 1 September 1991--30 November 1991

    SciTech Connect

    Marsh, H.

    1991-12-31

    During coal carbonization (pyrolysis), as during the combustion process of pulverized coal in a combustor, not all of the sulfur is released. Significant proportions become pat of the structure of the resultant coke and char. The combustion process of the char within the flames of the combustor in influenced dominantly by char morphology. This, in turn, controls the accessibility of oxidizing gases to the surfaces of the carbonaceous substance of the char. Mineral matter content, its extent and state of distribution, also exerts an influence on char morphology created during pyrolysis/carbonization. This complexity of coal renders it a very difficult material to study, systematically, to distinguish and separate out the contributing factors which influence combustion characteristics. Therefore, in such circumstances, it is necessary to simplify the systems by making use of model chars/cokes/carbons which can be made progressively more complex, but in a controlled way. In this way complicating influence in chars from coals can be eliminated, so enabling specific influences to be studied independently. It is important to note that preliminary work by Marsh and Gryglewicz (1990) indicated that levels of sulfur of about 3 to 5 wt % can reduce reactivities by 10 to 25%. The overall purpose of the study is to provide meaningful kinetic data to establish, quantitatively, the influence of organically-bound sulfur on the reactivity of carbons, and to ascertain if gasification catalysts are effective in the preferential removal of sulfur from the chars.

  14. Influence of urea additives on micellar morphology/protein conformation.

    PubMed

    Gull, Nuzhat; Kumar, Sanjeev; Ahmad, Basir; Khan, Rizwan Hassan; Kabir-ud-Din

    2006-08-01

    The present study highlights the fact that the effect of additives (urea, monomethylurea, thiourea) on the supramolecular assemblies and proteins is strikingly similar. To investigate the effect, a viscometeric study on sphere-to-rod transition (s-->r) was undertaken in a system (3.5% tetradecyltrimethylammonium bromide+0.05 M NaBr + 1-pentanol [P.M. Lindemuth, G.L. Bertand, J. Phys. Chem. 97 (1993) 7769]) in the presence and absence of the said additives. [1-pentanol] needed for s-->r (i.e. [1-pentanol]s-->r) was determined from the relative viscosity versus [1-pentanol] profiles. It was observed that the additives preponed as well as postponed s-->r depending upon their nature and concentrations. These effects are explained in terms of increased polarity of the medium and the adsorption ability of urea/monomethylurea on the charged surfactant monomers of the micelle. In case of thiourea, postponement of s-->r was observed throughout which is attributed to its structure. To derive an analogy between micelles and proteins the additive-induced conformational changes of the protein, bovine serum albumin (BSA) was taken to monitor secondary structural changes and tryptophanyl fluorescence. A marked increase in secondary structure (far-UVCD) and increased tryptophanyl fluorescence with a marked blue shift in lambdamax was observed in presence of low concentrations of urea or alkylurea. This indicates that a more compact environment is created in presence of these additives, if added judiciously. Addition of thiourea to BSA caused a marked quenching without any significant change in lambdamax. The large decrease in tryptophanyl emission in presence of low thiourea concentrations seems to be specific and related to thiourea structure as no corresponding changes were observed in urea/alkylurea. All these effects pertaining to protein behavior fall in line with that of morphological observations on the present as well as surfactant systems studied earlier [S. Kumar, N

  15. Specification of individual adult motor neuron morphologies by combinatorial transcription factor codes.

    PubMed

    Enriquez, Jonathan; Venkatasubramanian, Lalanti; Baek, Myungin; Peterson, Meredith; Aghayeva, Ulkar; Mann, Richard S

    2015-05-20

    How the highly stereotyped morphologies of individual neurons are genetically specified is not well understood. We identify six transcription factors (TFs) expressed in a combinatorial manner in seven post-mitotic adult leg motor neurons (MNs) that are derived from a single neuroblast in Drosophila. Unlike TFs expressed in mitotically active neuroblasts, these TFs do not regulate each other's expression. Removing the activity of a single TF resulted in specific morphological defects, including muscle targeting and dendritic arborization, and in a highly specific walking defect in adult flies. In contrast, when the expression of multiple TFs was modified, nearly complete transformations in MN morphologies were generated. These results show that the morphological characteristics of a single neuron are dictated by a combinatorial code of morphology TFs (mTFs). mTFs function at a previously unidentified regulatory tier downstream of factors acting in the NB but independently of factors that act in terminally differentiated neurons.

  16. Factors Influencing Likelihood of Voice Therapy Attendance.

    PubMed

    Misono, Stephanie; Marmor, Schelomo; Roy, Nelson; Mau, Ted; Cohen, Seth M

    2017-03-01

    Objective To identify factors associated with the likelihood of attending voice therapy among patients referred for it in the CHEER (Creating Healthcare Excellence through Education and Research) practice-based research network infrastructure. Study Design Prospectively enrolled cross-sectional study. Setting CHEER network of community and academic sites. Methods Data were collected on patient-reported demographics, voice-related diagnoses, voice-related handicap (Voice Handicap Index-10), likelihood of attending voice therapy (VT), and opinions on factors influencing likelihood of attending VT. The relationships between patient characteristics/opinions and likelihood of attending VT were investigated. Results A total of 170 patients with various voice-related diagnoses reported receiving a recommendation for VT. Of those, 85% indicated that they were likely to attend it, regardless of voice-related handicap severity. The most common factors influencing likelihood of VT attendance were insurance/copay, relief that it was not cancer, and travel. Those who were not likely to attend VT identified, as important factors, unclear potential improvement, not understanding the purpose of therapy, and concern that it would be too hard. In multivariate analysis, factors associated with greater likelihood of attending VT included shorter travel distance, age (40-59 years), and being seen in an academic practice. Conclusions Most patients reported plans to attend VT as recommended. Patients who intended to attend VT reported different considerations in their decision making from those who did not plan to attend. These findings may inform patient counseling and efforts to increase access to voice care.

  17. Neonatal thyroid function: influence of perinatal factors.

    PubMed Central

    Franklin, R C; Carpenter, L M; O'Grady, C M

    1985-01-01

    Indices of thyroid function were measured in 229 healthy term neonates at birth and at 5, 10, and 15 days of age. Results were analysed to assess whether maternal diabetes mellitus, toxaemia of pregnancy, intrapartum fetal distress, duration of labour, method of delivery, asphyxia at birth, race, sex, birthweight, birth length, head circumference, or method of feeding influenced any index. Thyroxine, the free thyroxine index, and free thyroxine concentrations at birth correlated with birthweight. Method of delivery influenced mean thyroxine and free thyroxine index values at birth and at age 5 days. Mean values of triiodothyronine, reverse triiodothyronine, thyroxine binding globulin, and thyroid stimulating hormone were not affected by any of the perinatal factors studied. Birthweight and perhaps method of delivery should be taken into account when interpreting neonatal thyroxine parameters but determination of thyroid stimulating hormone as a screen for congenital hypothyroidism in healthy term neonates circumvents these considerations. PMID:3977386

  18. Factors influencing aircraft ground handling performance

    NASA Technical Reports Server (NTRS)

    Yager, T. J.

    1983-01-01

    Problems associated with aircraft ground handling operations on wet runways are discussed and major factors which influence tire/runway braking and cornering traction capability are identified including runway characteristics, tire hydroplaning, brake system anomalies, and pilot inputs. Research results from tests with instrumented ground vehicles and aircraft, and aircraft wet runway accident investigation are summarized to indicate the effects of different aircraft, tire, and runway parameters. Several promising means are described for improving tire/runway water drainage capability, brake system efficiency, and pilot training to help optimize aircraft traction performance on wet runways.

  19. The influence factors of medical professionalism

    PubMed Central

    Lin, Yifei; Yin, Senlin; Lai, Sike; Tang, Ji; Huang, Jin; Du, Liang

    2016-01-01

    Abstract As the relationship between physicians and patients deteriorated in China recently, medical conflicts occurred more frequently now. Physicians, to a certain extent, also take some responsibilities. Awareness of medical professionalism and its influence factors can be helpful to take targeted measures and alleviate the contradiction. Through a combination of physicians’ self-assessment and patients’ assessment in ambulatory care clinics in Chengdu, this research aims to evaluate the importance of medical professionalism in hospitals and explore the influence factors, hoping to provide decision-making references to improve this grim situation. From February to March, 2013, a cross-sectional study was conducted in 2 tier 3 hospitals, 5 tier 2 hospitals, and 10 community hospitals through a stratified-random sampling method on physicians and patients, at a ratio of 1/5. Questionnaires are adopted from a pilot study. A total of 382 physicians and 1910 patients were matched and surveyed. Regarding the medical professionalism, the scores of the self-assessment for physicians were 85.18 ± 7.267 out of 100 and the scores of patient-assessment were 57.66 ± 7.043 out of 70. The influence factors of self-assessment were physicians’ working years (P = 0.003) and patients’ complaints (P = 0.006), whereas the influence factors of patient-assessment were patients’ ages (P = 0.001) and their physicians’ working years (P < 0.01) and satisfaction on the payment mode (P = 0.006). Higher self-assessment on the medical professionalism was in accordance with physicians of more working years and no complaint history. Higher patient-assessment was in line with elder patients, the physicians’ more working years, and higher satisfaction on the payment mode. Elder patients, encountering with physicians who worked more years in health care services or with higher satisfaction on the payment mode, contribute to higher scores in patient assessment part. The

  20. [Influence of weather factors on suicidal hangings].

    PubMed

    Trepińska, Janina; Piotrowicz, Katarzyna; Bakowski, Rafał; Bolechała, Filip; Trela, Franciszek

    2005-01-01

    The paper presents a certain biometeorological problem. The evaluation of influence of weather factors on frequency of suicidal cases by hanging in the area of Cracow City during 1991-2002 was examined. Rapid changes of air pressure, air temperature, hot, sweltering and sultry days, very frosty days, days with strong or foehn wind, days with thunderstorms, fog and haze were selected as unfavourable weather factors. They give an occasion for strong psychical stress. The results of detailed investigations are next: more frequency of cases of suicide during the advance of cold fronts, rapid decreases of air pressure during hot, sweltering and sultry days, days with thunderstorms and foehn winds in the Tatra Mountains.

  1. The appositional articular morphology of the talo-crural joint: the influence of substrate use on joint shape.

    PubMed

    Turley, Kevin; Frost, Stephen R

    2014-04-01

    The appositional articular morphology of the talo-crural joint is the third component of the joint complex. It is a site of internal integration of this highly stable functional evolutionary unit. Prior studies of the other two components, tibia and talus, demonstrated that substrate preference influenced their articular shape. This effect was unrelated to physical attributes (size and mass) and phylogeny (superfamily). The effect of this behavioral factor, substrate preference, on shape and integration of the appositional articular morphology was investigated. Two hundred forty-five matched distal tibial and proximal talar landmarked surfaces from 12 diverse Catarrhine taxa were studied. Shape effects due to the same factors previously studied were examined in the tibial and talar subsets and were highly significant (P < 0.0001). These were assessed using Multivariate Regression and Relative Warps analysis, and Permutation tests, with results consistent with prior unmatched cohorts. Substrate preference influenced shape and was unrelated to the other factors across taxa. Singular Warp analysis of the cross-covariance matrix revealed sorting of taxa by substrate use, unrelated to physical attributes and phylogeny. Finally, the sorting demonstrated a signal of convergent evolution among distantly related taxa and divergent evolution among closely related taxa reflecting substrate use. Results were consistent with a behavioral influence, substrate use, affecting articular shape and integration in this highly stable functional evolutionary unit, and signals with evolutionary implications.

  2. Factors influencing global antiretroviral procurement prices

    PubMed Central

    2009-01-01

    Background Antiretroviral medicines (ARVs) are one of the most costly parts of HIV/AIDS treatment. Many countries are struggling to provide universal access to ARVs for all people living with HIV and AIDS. Although substantial price reductions of ARVs have occurred, especially between 2002 and 2008, achieving sustainable access for the next several decades remains a major challenge for most low- and middle-income countries. The objectives of the present study were twofold: first, to analyze global ARV prices between 2005 and 2008 and associated factors, particularly procurement methods and key donor policies on ARV procurement efficiency; second, to discuss the options of procurement processes and policies that should be considered when implementing or reforming access to ARV programs. Methods An ARV-medicines price-analysis was carried out using the Global Price Reporting Mechanism from the World Health Organization. For a selection of 12 ARVs, global median prices and price variation were calculated. Linear regression models for each ARV were used to identify factors that were associated with lower procurement prices. Logistic regression models were used to identify the characteristics of those countries which procure below the highest and lowest direct manufactured costs. Results Three key factors appear to have an influence on a country's ARV prices: (a) whether the product is generic or not; (b) the socioeconomic status of the country; (c) whether the country is a member of the Clinton HIV/AIDS Initiative. Factors which did not influence procurement below the highest direct manufactured costs were HIV prevalence, procurement volume, whether the country belongs to the least developed countries or a focus country of the United States President's Emergency Plan For AIDS Relief. Conclusion One of the principal mechanisms that can help to lower prices for ARV over the next several decades is increasing procurement efficiency. Benchmarking prices could be one useful

  3. Linguistic Factors Influencing Speech Audiometric Assessment

    PubMed Central

    Krijger, Stefanie; Meeuws, Matthias; De Ceulaer, Geert

    2016-01-01

    In speech audiometric testing, hearing performance is typically measured by calculating the number of correct repetitions of a speech stimulus. We investigate to what extent the repetition accuracy of Dutch speech stimuli presented against a background noise is influenced by nonauditory processes. We show that variation in verbal repetition accuracy is partially explained by morpholexical and syntactic features of the target language. Verbs, prepositions, conjunctions, determiners, and pronouns yield significantly lower correct repetitions than nouns, adjectives, or adverbs. The reduced repetition performance for verbs and function words is probably best explained by the similarities in the perceptual nature of verbal morphology and function words in Dutch. For sentences, an overall negative effect of syntactic complexity on speech repetition accuracy was found. The lowest number of correct repetitions was obtained with passive sentences, reflecting the cognitive cost of processing a noncanonical sentence structure. Taken together, these findings may have important implications for the audiological practice. In combination with hearing loss, linguistic complexity may increase the cognitive demands to process sentences in noise, leading to suboptimal functional hearing in day-to-day listening situations. Using test sentences with varying degrees of syntactic complexity may therefore provide useful information to measure functional hearing benefits. PMID:27830152

  4. Linguistic Factors Influencing Speech Audiometric Assessment.

    PubMed

    Coene, Martine; Krijger, Stefanie; Meeuws, Matthias; De Ceulaer, Geert; Govaerts, Paul J

    2016-01-01

    In speech audiometric testing, hearing performance is typically measured by calculating the number of correct repetitions of a speech stimulus. We investigate to what extent the repetition accuracy of Dutch speech stimuli presented against a background noise is influenced by nonauditory processes. We show that variation in verbal repetition accuracy is partially explained by morpholexical and syntactic features of the target language. Verbs, prepositions, conjunctions, determiners, and pronouns yield significantly lower correct repetitions than nouns, adjectives, or adverbs. The reduced repetition performance for verbs and function words is probably best explained by the similarities in the perceptual nature of verbal morphology and function words in Dutch. For sentences, an overall negative effect of syntactic complexity on speech repetition accuracy was found. The lowest number of correct repetitions was obtained with passive sentences, reflecting the cognitive cost of processing a noncanonical sentence structure. Taken together, these findings may have important implications for the audiological practice. In combination with hearing loss, linguistic complexity may increase the cognitive demands to process sentences in noise, leading to suboptimal functional hearing in day-to-day listening situations. Using test sentences with varying degrees of syntactic complexity may therefore provide useful information to measure functional hearing benefits.

  5. Landslide forecasting and factors influencing predictability

    NASA Astrophysics Data System (ADS)

    Intrieri, Emanuele; Gigli, Giovanni

    2016-11-01

    Forecasting a catastrophic collapse is a key element in landslide risk reduction, but it is also a very difficult task owing to the scientific difficulties in predicting a complex natural event and also to the severe social repercussions caused by a false or missed alarm. A prediction is always affected by a certain error; however, when this error can imply evacuations or other severe consequences a high reliability in the forecast is, at least, desirable. In order to increase the confidence of predictions, a new methodology is presented here. In contrast to traditional approaches, this methodology iteratively applies several forecasting methods based on displacement data and, thanks to an innovative data representation, gives a valuation of the reliability of the prediction. This approach has been employed to back-analyse 15 landslide collapses. By introducing a predictability index, this study also contributes to the understanding of how geology and other factors influence the possibility of forecasting a slope failure. The results showed how kinematics, and all the factors influencing it, such as geomechanics, rainfall and other external agents, are key concerning landslide predictability.

  6. Factors Influencing Endometrial Thickness in Postmenopausal Women

    PubMed Central

    Hebbar, S; Chaya, V; Rai, L; Ramachandran, A

    2014-01-01

    Background: Cut-off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. Aim: To study the various factors influencing the ET in postmenopausal women. Subjects and Methods: This was a prospective observational study. A total of 110 postmenopausal women underwent detailed history taking, clinical examination, and transvaginal scan for uterine volume and ovarian volume. The volumes were calculated by using ellipsoid formula: Width × thickness × height × 0.523. The variation in ET with respect to the influencing factors such as age, duration of menopause, parity, body mass index (BMI), medical illness like diabetes/hypertension, drugs like tamoxifen, presence of myoma, uterine volume, ovarian volume, and serum estradiol (in selected patients) were measured. Descriptive analysis was performed using SPSS software (version 16, Chicago II, USA) to obtain mean, standard deviation (SD), 95% confidence intervals (CIs) and inter quartile ranges. Comparison of means was carried out using analysis of variance. Results: The mean (SD) age of the patients was 55.4 (6.91) years (95% CI, 54.1, 56.7). The mean (SD) age at menopause was 47.95 (3.90) years (95% CI, 47.2, 48.7) and the mean (SD) duration of menopause was 7.27 (6.65) years (95% CI, 6.01, 8.53). The mean (SD) ET was 3.8 (2.3) mm (95% CI, 3.36, 4.23). Medical illness like diabetes and hypertension did not alter the ET. ET increased as BMI increased and it was statistically significant. The presence of myoma increased uterine volume significantly and was associated with thick endometrial stripe. Similarly, whenever the ovaries were visualized and as the ovarian volume increased, there was an increase in ET. When ET was > 4 mm (n = 37), they were offered endocel, of which 16 agreed to undergo the procedure. None were found to have endometrial cancer

  7. How are River Discharge - Suspended Sediment Relations Influenced by Watershed and Channel-Floodplain Morphology?

    NASA Astrophysics Data System (ADS)

    Vaughan, A. A.; Belmont, P.

    2015-12-01

    Erosion, transport and deposition of fine sediment (clay, silt and fine sand) influence the form and function of river systems. Excess suspended sediment degrades stream ecosystems and is implicated as a leading cause of water quality and aquatic life impairment. Consequently, understanding the factors that control fine sediment transport regimes is an interesting topic for basic science and one that has important management and policy implications. Fine sediment is mostly transported in suspension as a non-capacity load; transport rates are dependent on sediment supply in addition to a river's transport capacity. Many studies have investigated watershed-scale topographic, hydrologic, climatic, and land use influences on fine sediment erosion and transport regimes. Several recent studies in a wide range of landscapes have demonstrated that the majority of suspended sediment may be sourced from the near-channel environment; therefore, near-channel morphological characteristics may provide better predictive power compared to watershed averages. This study analyzes recent total suspended solids (TSS) data from 45 gages on 35 separate rivers. The rivers span the state of Minnesota, draining basins ranging from 33 km2 to 68100 km2 with distinct settings in terms of topography, land cover, hydrology and geologic history. We generate rating curves of the form TSS = aQb, where Q is normalized discharge and a and b are parameters that describe the shape of the relations. Values of a range from 4 to 138 mg/L; b values range from -0.53 to 1.86. We use high resolution lidar topography data to characterize the near-channel environment upstream of gages. In addition to commonly studied metrics describing the topographic, climatic/hydrologic and land use setting of the basin, we extract near-channel morphometrics that we hypothesize to influence fine sediment generation and transport: the difference in height of banks/bluffs (a measure of the amount of material available to be

  8. Jaw-muscle architecture and mandibular morphology influence relative maximum jaw gapes in the sexually dimorphic Macaca fascicularis.

    PubMed

    Terhune, Claire E; Hylander, William L; Vinyard, Christopher J; Taylor, Andrea B

    2015-05-01

    Maximum jaw gape is a performance variable related to feeding and non-feeding oral behaviors, such as canine gape displays, and is influenced by several factors including jaw-muscle fiber architecture, muscle position on the skull, and jaw morphology. Maximum gape, jaw length, and canine height are strongly correlated across catarrhine primates, but relationships between gape and other aspects of masticatory apparatus morphology are less clear. We examine the effects of jaw-adductor fiber architecture, jaw-muscle leverage, and jaw form on gape in an intraspecific sample of sexually dimorphic crab-eating macaques (Macaca fascicularis). As M. fascicularis males have relatively larger maximum gapes than females, we predict that males will have muscle and jaw morphologies that facilitate large gape, but these morphologies may come at some expense to bite force. Male crab-eating macaques have relatively longer jaw-muscle fibers, masseters with decreased leverage, and temporomandibular joint morphologies that facilitate the production of wide gapes. Because relative canine height is correlated with maximum gape in catarrhines, and males have relatively longer canines than females, these results support the hypothesis that male M. fascicularis have experienced selection to increase maximum gape. The sexes do not differ in relative masseter physiologic cross-sectional area (PCSA), but males compensate for a potential trade-off between muscle excursion versus muscle force with increased temporalis weight and PCSA. This musculoskeletal configuration is likely functionally significant for behaviors involving aggressive canine biting and displays in male M. fascicularis and provides additional evidence supporting the multifactorial nature of the catarrhine masticatory apparatus. Our results have implications for the evolution of craniofacial morphology in catarrhine primates and reinforce the importance of evaluating additional factors other than feeding behavior and diet

  9. Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology

    PubMed Central

    Rabey, Karyne N.; Green, David J.; Taylor, Andrea B.; Begun, David R.; Richmond, Brian G.; McFarlin, Shannon C.

    2014-01-01

    The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual’s past behaviour. PMID:25467113

  10. Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology.

    PubMed

    Rabey, Karyne N; Green, David J; Taylor, Andrea B; Begun, David R; Richmond, Brian G; McFarlin, Shannon C

    2015-01-01

    The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour.

  11. [Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba].

    PubMed

    Quesada, Eddy Martínez

    2009-01-01

    Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba. The foliar morphology of representative antophytes in four rainforest types of Eastern Cuba was studied in relation to the main abiotic factors. Although there are several leaf types in these forests, the microphyll type is the most important among endemic species in the ophiolites complex and the Montane rainforest. At the Lowland rainforest (metamorphic complex) the mesophyll leaf was the most important. Most foliar epidermis had structures normally found in mesomorphic plants, but xeromorphic and higromorphic morphologies were also present.

  12. Influence of substrate miscut angle on surface morphology and luminescence properties of AlGaN

    SciTech Connect

    Kusch, Gunnar Edwards, Paul R.; Bruckbauer, Jochen; Martin, Robert W.; Li, Haoning; Parbrook, Peter J.; Sadler, Thomas C.

    2014-03-03

    The influence of substrate miscut on Al{sub 0.5}Ga{sub 0.5} N layers was investigated using cathodoluminescence (CL) hyperspectral imaging and secondary electron imaging in an environmental scanning electron microscope. The samples were also characterized using atomic force microscopy and high resolution X-ray diffraction. It was found that small changes in substrate miscut have a strong influence on the morphology and luminescence properties of the AlGaN layers. Two different types are resolved. For low miscut angle, a crack-free morphology consisting of randomly sized domains is observed, between which there are notable shifts in the AlGaN near band edge emission energy. For high miscut angle, a morphology with step bunches and compositional inhomogeneities along the step bunches, evidenced by an additional CL peak along the step bunches, are observed.

  13. Examinations of factors influencing toe grip strength

    PubMed Central

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya

    2016-01-01

    [Purpose] This study examined the relationship between toe grip strength and its associated factors by focusing on factors that were suggested to have a relationship with toe grip strength in previous studies, aiming to clarify the factors influencing the toe grip strength of healthy women. [Subjects and Methods] Twelve healthy young women were selected for this study. Their toe grip strength, angular changes in their ankle joint during toe grip, maximum voluntary contraction activities of the rectus femoris, biceps femoris, and tibialis anterior muscles, and the medial head of the gastrocnemius muscles were measured using electromyography. Their toe curl ability, foot-arch height ratio, and weight were also measured. [Results] Multiple regression analysis demonstrated that the predictors of toe grip strength in the resulting model were foot-arch height ratio and the percentage of integrated electromyography (%IEMG) of the tibialis anterior muscle, as the dependent variables. This reveals that women whose tibialis anterior muscle %IEMG values and foot-arch height ratio are high have greater %IEMG values have greater toe grip strength. [Conclusion] These findings suggest a significant relationship between foot-arch height ratio and toe grip strength, with a reciprocal interaction. These findings further indicate that the risk of falls by the elderly could be decreased if toe grip strength were enhanced, by increasing the height of a low foot-arch with the help of an inserted insole. PMID:27942134

  14. Examinations of factors influencing toe grip strength.

    PubMed

    Soma, Masayuki; Murata, Shin; Kai, Yoshihiro; Nakae, Hideyuki; Satou, Yousuke; Murata, Jun; Miyazaki, Junya

    2016-11-01

    [Purpose] This study examined the relationship between toe grip strength and its associated factors by focusing on factors that were suggested to have a relationship with toe grip strength in previous studies, aiming to clarify the factors influencing the toe grip strength of healthy women. [Subjects and Methods] Twelve healthy young women were selected for this study. Their toe grip strength, angular changes in their ankle joint during toe grip, maximum voluntary contraction activities of the rectus femoris, biceps femoris, and tibialis anterior muscles, and the medial head of the gastrocnemius muscles were measured using electromyography. Their toe curl ability, foot-arch height ratio, and weight were also measured. [Results] Multiple regression analysis demonstrated that the predictors of toe grip strength in the resulting model were foot-arch height ratio and the percentage of integrated electromyography (%IEMG) of the tibialis anterior muscle, as the dependent variables. This reveals that women whose tibialis anterior muscle %IEMG values and foot-arch height ratio are high have greater %IEMG values have greater toe grip strength. [Conclusion] These findings suggest a significant relationship between foot-arch height ratio and toe grip strength, with a reciprocal interaction. These findings further indicate that the risk of falls by the elderly could be decreased if toe grip strength were enhanced, by increasing the height of a low foot-arch with the help of an inserted insole.

  15. Morphology Analysis and Optimization: Crucial Factor Determining the Performance of Perovskite Solar Cells.

    PubMed

    Zeng, Wenjin; Liu, Xingming; Guo, Xiangru; Niu, Qiaoli; Yi, Jianpeng; Xia, Ruidong; Min, Yong

    2017-03-24

    This review presents an overall discussion on the morphology analysis and optimization for perovskite (PVSK) solar cells. Surface morphology and energy alignment have been proven to play a dominant role in determining the device performance. The effect of the key parameters such as solution condition and preparation atmosphere on the crystallization of PVSK, the characterization of surface morphology and interface distribution in the perovskite layer is discussed in detail. Furthermore, the analysis of interface energy level alignment by using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy is presented to reveals the correlation between morphology and charge generation and collection within the perovskite layer, and its influence on the device performance. The techniques including architecture modification, solvent annealing, etc. were reviewed as an efficient approach to improve the morphology of PVSK. It is expected that further progress will be achieved with more efforts devoted to the insight of the mechanism of surface engineering in the field of PVSK solar cells.

  16. WETLAND MORPHOLOGIC AND BIOGEOGRAPHIC INFLUENCES ON ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    We are testing the influence of wetland morphology (protected vs. riverine) and biogeography (upper vs. lower Great Lakes) on algal responses to nutrients in Great Lakes Coastal wetlands. Principal components analysis using nutrient-specific GIS data was used to select sites wit...

  17. Incidence, risk factors, and morphology in operating microscope light retinopathy

    SciTech Connect

    Khwarg, S.G.; Linstone, F.A.; Daniels, S.A.; Isenberg, S.J.; Hanscom, T.A.; Geoghegan, M.; Straatsma, B.R.

    1987-03-15

    A review of 135 consecutive cataract operations identified ten cases (7.4%) of operating microscope light retinopathy. Ophthalmoscopically, these light retinopathy lesions appeared as a focal pigment epithelial change with varying degrees of pigment clumping in the center. Fluorescein angiography accentuated the lesion by demonstrating a sharply demarcated transmission defect, occasionally with multiple satellite lesions. The shape of the lesion matched the shape of the illuminating source of the particular operating microscope used during the surgery. The most significant risk factor associated with the production of these light retinopathy lesions was prolonged operating time. Mean total operating time for the ten patients with light retinopathy was 51 minutes longer than for those without (P less than .0001). Other significant associated factors were the presence of diabetes mellitus (P less than .03), younger age (P less than .05), and the use of hydrochlorothiazide (P less than .04).

  18. [Bioavailability and factors influencing its rate].

    PubMed

    Vraníková, Barbora; Gajdziok, Jan

    2015-01-01

    Bioavailability can be defined as the rate and range of active ingredient absorption, when it becomes available in the systemic circulation or at the desired site of drug action, respectively. Drug bioavailability after oral administration is affected by anumber of different factors, including physicochemical properties of the drug, physiological aspects, the type of dosage form, food intake, biorhythms, and intra- and interindividual variability of the human population. This article is the first from the series dealing with the bioavailability and methods leading to its improvement. The aim of the present paper is to provide an overview of aspects influencing the rate of bioavailability after oral administration of the active ingredient. Subsequentarticles will provide detailed descriptions of methods used for dug bioavailability improvement, which are here only summarized.

  19. Factors influencing the morbidity of colostomy closure.

    PubMed

    Demetriades, D; Pezikis, A; Melissas, J; Parekh, D; Pickles, G

    1988-04-01

    A series consisting of 110 patients who had colostomy closure was studied in an attempt to define the role of various factors in causing colon-related morbidity. The overall complication rate was 14.5 percent (wound sepsis 11.8 percent and anastomotic leak 2.7 percent). Patient age, the underlying pathologic abnormality (trauma versus nontrauma), the type of colostomy (loop versus end colostomy), the site of the stoma (right side, left side, or transverse), whether a drain was inserted or not, and the timing of the operation did not influence morbidity. Oral preoperative antibiotics appeared to be associated with less morbidity than parenteral antibiotics (p less than 0.01), and experienced surgeons had less complications than junior surgeons (p less than 0.05).

  20. Factors influencing nurses' perceptions of occupational safety.

    PubMed

    Samur, Menevse; Intepeler, Seyda Seren

    2017-01-02

    To determine nurses' perceptions of occupational safety and their work environment and examine the sociodemographic traits and job characteristics that influence their occupational safety, we studied a sample of 278 nurses. According to the nurses, the quality of their work environment is average, and occupational safety is insufficient. In the subdimensions of the work environment scale, it was determined that the nurses think "labor force and other resources" are insufficient. In the occupational safety subdimensions "occupational illnesses and complaints" and "administrative support and approaches," they considered occupational safety to be insufficient. "Doctor-nurse-colleague relationships," "exposure to violence," and "work unit" (eg, internal medicine, surgical, intensive care) are the main factors that affect occupational safety. This study determined that hospital administrations should develop and immediately implement plans to ameliorate communication and clinical precautions and to reduce exposure to violence.

  1. Factors influencing acrylamide formation in gingerbread.

    PubMed

    Amrein, Thomas M; Schönbächler, Barbara; Escher, Felix; Amadò, Renato

    2005-01-01

    The influence of ingredients, additives, and process conditions on the acrylamide formation in gingerbread was investigated. The sources for reducing sugars and free asparagine were identified and the effect of different baking agents on the acrylamide formation was evaluated. Ammonium hydrogencarbonate strongly enhanced the acrylamide formation, but its N-atom was not incorporated into acrylamide, nor did acrylic acid form acrylamide in gingerbread. Acrylamide concentration and browning intensity increased both with baking time and correlated with each other. The use of sodium hydrogencarbonate as baking agent reduced the acrylamide concentration by more than 60%. Free asparagine was a limiting factor for acrylamide formation, but the acrylamide content could also be lowered by replacing reducing sugars with sucrose or by adding moderate amounts of organic acids. A significant reduction of the acrylamide content in gingerbread can be achieved by using sodium hydrogencarbonate as baking agent, minimizing free asparagine, and avoiding prolonged baking.

  2. Gait mechanics influence healthy cartilage morphology and osteoarthritis of the knee.

    PubMed

    Andriacchi, Thomas P; Koo, Seungbum; Scanlan, Sean F

    2009-02-01

    The response of healthy and diseased cartilage of the knee to the mechanics of walking is examined, with the goal of providing insight into the relationship between the kinematics and kinetics of the knee during walking and the maintenance of cartilage health. The combination of information from three-dimensional thickness models of cartilage derived from magnetic resonance imaging and the analysis of the interaction between load at the knee and kinematic changes during walking associated with loss of the anterior cruciate ligament demonstrated the importance of considering walking mechanics as an important factor in the initiation and progression of osteoarthritis. In particular, this material suggests that knee cartilage becomes conditioned to loading and to the large number of repetitive cycles of loading that occur during walking and that healthy cartilage homeostasis is maintained as long as there are no changes to the normal patterns of locomotion, the structure of the knee joint, or cartilage biology. Thus, there is the potential for a degenerative pathway to be initiated when a condition such as anterior cruciate ligament injury causes the repetitive loading during walking to shift to a new location. The sensitivity of cartilage to the kinematic changes is illustrated with the anterior cruciate ligament-deficient knee and the regional variations in cartilage morphology. The material presented here supports the conclusion that individual variations in the range of loading and kinematics at the knee during walking can have a profound influence on the initiation and progression of osteoarthritis of the knee.

  3. Splat Morphology and Influence of Feeding Rate During Reactive Plasma Spray of Aluminum Powder

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Fukumoto, Masahiro

    2016-12-01

    Fabrication of aluminum nitride (AlN) coatings using conventional plasma spraying processes directly has been deemed impossible. It is attributed to the thermal decomposition of the AlN feedstock particles during spraying without a stable melting phase. Using the reactivity of the plasma (reactive plasma spraying: RPS) showed a promising consideration for in situ formation of AlN thermally sprayed coatings. Several AlN-based coatings were fabricated through the RPS of aluminum powders in the N2/H2 plasma. The focus of this study is in discussing the morphology of splat deposition during the nitriding of Al particles. Furthermore, the influence of the feeding rate during the RPS and nitriding of Al powders will be investigated. The nitride content, as well as the unreacted molten Al phase, strongly influences splat deposition and morphology during the RPS of Al. The collected splats can be divided into reacted, partially reacted, and unreacted splats. The reacted splats tend to show a disk or egg-shell shape. The partially reacted mainly had outside nitride shells and an unreacted molten Al part in the center. The unreacted splats tended to show a splash shape. The main controlling factor is the time of the droplet impact on the substrate during the reaction sequence. The particle size and spray distance showed significant effects on the splat formation due to their effect on the nitriding conversion and the melting behavior of the particles during RPS nitriding. The powder feeding rate was investigated through increasing the injection rate and by using a low carrier gas flow rate. Increasing the powder feeding rate significantly improved the coating thickness. However, it suppressed the nitriding conversion of the large Al particles. Thus, with increasing the amount of the powder in the plasma, the Al molten particles are easily aggregated and agglomerate together upon colliding on the substrate with an AlN shell on the surface. This prevents the N2 from having

  4. Factors controlling growth and morphology of early Miocene stromatolites from Montaigu-le-Blin, France

    NASA Astrophysics Data System (ADS)

    Bontognali, Tomaso R. R.; Barilaro, Federica; McKenzie, Judith A.; Vasconcelos, Crisogono

    2015-04-01

    A large variety of stromatolite morphotypes are present in the early Miocene sedimentary sequence that outcrops in the region of Montaigu-le-Blin, France. Thanks to its good degree of preservation, this formation is an ideal place to evaluate the key factors controlling the occurrence and morphology of the stromatolites, as well as to study the diagenetic processes that transform a soft, slimy lithifying microbialite into a solid, laminated sedimentary rock. Facies analysis suggests that the Montaigu-le-Blin stromatolites formed in shallow waters, in a restricted, laterally heterogeneous basin. Various evidence suggests a biological origin for the stromatolites, whose formation cannot be explained through abiotic background precipitation driven by evaporation, temperature changes, or migration of metamorphic fluids. Microscopic observations revealed that the Montaigu-le-Blin stromatolites are mainly comprised of authigenic calcite that precipitated directly from the basin waters (no evidence for trapping and binding) in close association with algae, microbial cells, and exopolymeric substances. Well-preserved microfossils of photosynthetic organisms are widespread within the thin sections. The calcite constituting the stromatolites is characterized by positive δ13C values (1.7 to 4.4 o), suggesting that microbial mediation of calcite was mainly related to the metabolic activity of photosynthetic organisms or anoxygenic phototrophs, and not to metabolisms in which organic material is degraded (e.g. sulfate reduction). The laminated habit of the stromatolites results from alternating layers of porous, digit-like sparite and more compacted organic-rich micrite. No correlation was identified, through isotopic analysis, between these two types of laminae and external environmental factors (i.e. temperature, salinity, eutrophication state). Rather, we hypothesize that periodic fluctuations in the dominant microbial/algal species within the mat influenced the morphology

  5. Influencing Factors of Thermogenic Adipose Tissue Activity

    PubMed Central

    Zhang, Guoqing; Sun, Qinghua; Liu, Cuiqing

    2016-01-01

    Obesity is an escalating public health challenge and contributes tremendously to the disease burden globally. New therapeutic strategies are required to alleviate the health impact of obesity-related metabolic dysfunction. Brown adipose tissue (BAT) is specialized for dissipating chemical energy for thermogenesis as a defense against cold environment. Intriguingly, the brown-fat like adipocytes that dispersed throughout white adipose tissue (WAT) in rodents and humans, called “brite” or “beige” adipocytes, share similar thermogenic characteristics to brown adipocytes. Recently, researchers have focused on cognition of these thermogenic adipose tissues. Some factors have been identified to regulate the development and function of thermogenic adipose tissues. Cold exposure, pharmacological conditions, and lifestyle can enhance non-shivering thermogenesis and metabolism via some mechanisms. However, environmental pollutants, such as ambient fine particulates and ozone, may impair the function of these thermogenic adipose tissues and thereby induce metabolic dysfunction. In this review, the origin, function and influencing factors of thermogenic adipose tissues were summarized and it will provide insights into identifying new therapeutic strategies for the treatment of obesity and obesity-related diseases. PMID:26903879

  6. Influence of different solvents on the morphology of APTMS-modified silicon surfaces

    NASA Astrophysics Data System (ADS)

    Jakša, G.; Štefane, B.; Kovač, J.

    2014-10-01

    In this study 3-aminopropyltrimethoxysilane (APTMS) was used for the modification of single-crystal silicon wafers (1 1 1). We deposited the self-assembled layers from a solution of APTMS in five solvents with different polarities under various reaction conditions. The influence of the different solvents on the morphology of the modified surfaces was studied, since the possible heterogeneity may significantly influence the application of such surfaces. The surface composition and the chemical bonding were characterized by X-ray photoelectron spectroscopy and the morphology of the modified surfaces was investigated using atomic force microscopy and scanning electron microscopy. Our results show that the amount of coatings and the morphology of the modified surface strongly depend on the type of solvent. Silanization carried out in acetonitrile and toluene leads to the formation of a rough surface with a large density of APTMS polymerized molecules in the form of islands. The surfaces modified in N,N-dimethylformamide were smoother, with a lower density of APTMS islands. When using acetone and ethanol as a solvent we prepared a smooth, thin, modified surface, with a very low density of the APTMS islands. We discuss the influence of the polarity/nature of the solvents on the morphology of the modified surfaces.

  7. Predictive influence of phonological processing, morphological/syntactic skill, and naming speed on spelling performance.

    PubMed

    Plaza, Monique; Cohen, Henri

    2004-07-01

    This paper focuses on the predictive influence of phonological awareness, morphological/syntactic skill, and naming speed on spelling. The retrospective study correlated spelling performance in a group of 199 French-speaking children at the end of grade 2 with earlier capacities for phonemic manipulation, morphological/syntactic correction, and naming speed, assessed at the end of grade 1. The results are consistent with an integrative model that challenges the unitary phonological disorder hypothesis and confirmed that in French, as in other languages, naming speed is an independent predictor of reading performance.

  8. Influence of interphase morphology on adhesion and composite durability in semicrystalline polymer matrix composites

    SciTech Connect

    Clark, R.L. Jr.; Kander, R.G.

    1996-12-31

    The microstructure of the interphase in semicrystalline polymer matrix composites has a dramatic influence on their mechanical properties. Studies have been performed to alter this region and to correlate various interphase morphologies with changes in fiber-matrix adhesion. A reinforced nylon 66 composite, when subjected to specific thermal histories, contains an interphase composed of transcrystallinity. This region has been altered by coating fibers with a diluent, poly(vinyl pyrrolidone), and/or adding the diluent to the matrix material in very small quantities. Interphase morphology was investigated with optical microscopy, and adhesion was measured using a modified fiber pull-out test. It was found that transcrystallinity increases the interfacial shear strength. The effect different interphase morphologies have on the durability of bulk composite samples is currently under investigation.

  9. On the influence of substrate morphology and surface area on phytofauna

    USGS Publications Warehouse

    Becerra-Munoz, S.; Schramm, H.L.

    2007-01-01

    The independent effects and interactions between substrate morphology and substrate surface area on invertebrate density or biomass colonizing artificial plant beds were assessed in a clear-water and a turbid playa lake in Castro County, Texas, USA. Total invertebrate density and biomass were consistently greater on filiform substrates than on laminar substrates with equivalent substrate surface areas. The relationship among treatments (substrates with different morphologies and surface areas) and response (invertebrate density or biomass) was assessed with equally spaced surface areas. Few statistically significant interactions between substrate morphology and surface area were detected, indicating that these factors were mostly independent from each other in their effect on colonizing invertebrates. Although infrequently, when substrate morphology and surface area were not independent, the effects of equally spaced changes in substrate surface area on the rate of change of phytofauna density or biomass per unit of substrate surface area were dependent upon substrate morphology. The absence of three-way interactions indicated that effects of substrate morphology and substrate area on phytofauna density or biomass were independent of environmental conditions outside and inside exclosures. ?? 2006 Springer Science+Business Media B.V.

  10. [Factors influencing the decision to seek abortion].

    PubMed

    af Geijerstam, G

    1980-02-13

    In 1974, a law was passed in Sweden allowing abortion on demand. Studies are now being undertaken to determine the effect of this law in 3 important areas: abortion counselling, abortion frequency, and possible means of psychological assistance for those who undergo abortions. Abortion must be studied as it affects the entire reproductive chain, in which there are 4 main links: frequency of sexual intercourse, physiological fertility, motivation to have children, and measures taken for birth control. In an agricultural society, children have a value as part of the work force and for retirement security; in a modern society, children have a much more abstract value. The reproductive chain is also affected by the increasing number of unmarried couples living together. There is a need to interview individuals and families to determine "fertility choice behavior", which can help to illuminate motivations for becoming pregnant or seeking abortion. These studies could help determine the perceived advantages and disadvantages of having children and what factors influence "fertility choice behavior".

  11. Trigger sequence can influence final morphology in the self-assembly of asymmetric telechelic polymers.

    PubMed

    Kumar, Aatish; Lowe, Christopher P; Cohen Stuart, Martien A; Bolhuis, Peter G

    2016-02-21

    We report on a numerical study of polymer network formation of asymmetric biomimetic telechelic polymers with two reactive ends based on a self-assembling collagen, elastin or silk-like polypeptide sequence. The two reactive ends of the polymer can be activated independently using physicochemical triggers such as temperature and pH. We show, using a simple coarse grained model that the order in which this triggering occurs influences the final morphology. For both of collagen-silk and elastin-silk topologies we find that for relatively short connector chains the morphology of the assembly is greatly influenced by the order of the trigger, whereas for longer chains the equilibrium situation is more easily achieved. Moreover, self-assembly is greatly enhanced at moderate collagen interaction strength, due to facilitated binding and unbinding of the peptides. This finding indicates that both the trigger sequence and strength can be used to steer self-assembly in these biomimetic polymer systems.

  12. What Factors Influence a Teacher's Commitment to Student Learning?

    ERIC Educational Resources Information Center

    Dannetta, Vincent

    2002-01-01

    Study of the personal, organizational, student-related factors influencing teacher commitment to student learning. Finds, for example, that among personal factors intrinsic rewards are more important than extrinsic rewards, that among organization factors collegiality is an important influence on commitment to student learning, and that among…

  13. Burkholderia cenocepacia ShvR-regulated genes that influence colony morphology, biofilm formation, and virulence.

    PubMed

    Subramoni, Sujatha; Nguyen, David T; Sokol, Pamela A

    2011-08-01

    Burkholderia cenocepacia is an opportunistic pathogen that primarily infects cystic fibrosis (CF) patients. Previously, we reported that ShvR, a LysR regulator, influences colony morphology, virulence, and biofilm formation and regulates the expression of an adjacent 24-kb genomic region encoding 24 genes. In this study, we report the functional characterization of selected genes in this region. A Tn5 mutant with shiny colony morphology was identified with a polar mutation in BCAS0208, predicted to encode an acyl-coenzyme A dehydrogenase. Mutagenesis of BCAS0208 and complementation analyses revealed that BCAS0208 is required for rough colony morphology, biofilm formation, and virulence on alfalfa seedlings. It was not possible to complement with BCAS0208 containing a mutation in the catalytic site. BCAS0201, encoding a putative flavin adenine dinucleotide (FAD)-dependent oxidoreductase, and BCAS0207, encoding a putative citrate synthase, do not influence colony morphology but are required for optimum levels of biofilm formation and virulence. Both BCAS0208 and BCAS0201 contribute to pellicle formation, although individual mutations in each of these genes had no appreciable effect on pellicle formation. A mutant with a polar insertion in BCAS0208 was significantly less virulent in a rat model of chronic lung infection as well as in the alfalfa model. Genes in this region were shown to influence utilization of branched-chain fatty acids, tricarboxylic acid cycle substrates, l-arabinose, and branched-chain amino acids. Together, our data show that the ShvR-regulated genes BCAS0208 to BCAS0201 are required for the rough colony morphotype, biofilm and pellicle formation, and virulence in B. cenocepacia.

  14. GROUP AND ORGANIZATIONAL FACTORS INFLUENCING CREATIVITY.

    DTIC Science & Technology

    SOCIAL COMMUNICATION, GROUP DYNAMICS, MOTIVATION, SOCIOMETRICS, MEASUREMENT, BEHAVIOR, CULTURE, PERSONALITY, COMPUTER PROGRAMMING, APTITUDE TESTS, COMPUTERS, LEADERSHIP, PSYCHOLOGICAL TESTS, FACTOR ANALYSIS.

  15. AIM 2 inflammasomes regulate neuronal morphology and influence anxiety and memory in mice

    PubMed Central

    Wu, Pei-Jung; Liu, Hsin-Yu; Huang, Tzyy-Nan; Hsueh, Yi-Ping

    2016-01-01

    Inflammasomes are the protein assemblies that consist of inflammasome sensors, adaptor apoptosis-associated speck-like proteins containing a CARD (ASC) and inflammasome caspase. Inflammasomes sense multiple danger signals via various inflammasome sensors and consequently use caspase to trigger proteolytic processing and secretion of IL-1β cytokines. Recent studies have suggested that neurons use their own innate immune system to detect danger signals and regulate neuronal morphology. Here, we investigate whether inflammasomes, the critical components of innate immunity, participate in regulation of neuronal morphology and function. Among various sensors, Absent in melanoma 2 (Aim2) expression in neurons is most prominent. Adding synthetic double-stranded DNA (dsDNA) to cultured neurons induces IL-1β secretion in an AIM2-dependent manner and consequently downregulates dendritic growth but enhances axon extension. The results of Aim2 knockout and knockdown show that AIM2 acts cell-autonomously to regulate neuronal morphology. Behavioral analyses further reveal that Aim2−/− mice exhibit lower locomotor activity, increased anxious behaviors and reduced auditory fear memory. In conclusion, our study suggests that AIM2 inflammasomes regulate neuronal morphology and influence mouse behaviors. PMID:27561456

  16. Influence of curvature on the morphology of brain microvascular endothelial cells

    NASA Astrophysics Data System (ADS)

    Ye, Mao; Yang, Zhen; Wong, Andrew; Searson, Peter; Searson Group Team

    2013-03-01

    There are hundreds or thousands of endothelial cells around the perimeter of a single artery or vein, and hence an individual cell experiences little curvature. In contrast, a single endothelial cell may wrap around itself to form the lumen of a brain capillary. Curvature plays a key role in many biological, chemical and physical processes, however, its role in dictating the morphology and polarization of brain capillary endothelial cells has not been investigated. We hypothesize that curvature and shear flow play a key role in determining the structure and function of the blood-brain barrier (BBB). We have developed the ``rod'' assay to study the influence of curvature on the morphology of confluent monolayers of endothelial cells. In this assay cells are plated onto glass rods pulled down to the desired diameter in the range from 5 - 500 μm and coated with collagen. We show that curvature has a significant influence on the morphology of endothelial cells and may have an important role in blood-brain barrier function.

  17. Artificial water sediment regulation scheme influences morphology, hydrodynamics and nutrient behavior in the Yellow River estuary

    NASA Astrophysics Data System (ADS)

    Xu, Bochao; Yang, Disong; Burnett, William C.; Ran, Xiangbin; Yu, Zhigang; Gao, Maosheng; Diao, Shaobo; Jiang, Xueyan

    2016-08-01

    Anthropogenic controls on water and sediment may play important roles in river system transformations and morphological evolution, which could further affect coastal hydrodynamics and nutrient behavior. We used geochemical tracers to evaluate the influence of an intentional large release of water and sediment during the so-called "Water Sediment Regulation Scheme" (WSRS) on estuarine morphology, hydrodynamics and nutrients in the Yellow River estuary, China. We discovered that there was a newly formed small delta in the river mouth after the 2013 WSRS. This new morphologic feature altered terrestrial material distribution patterns from a single plume to a two-plume pattern within the estuary. Our results show that the WSRS significantly influenced the study area in the following ways: (1) Radium and nutrient concentrations were significantly elevated (two to four times), especially along the two river outlets. (2) Estuarine mixing was about two times stronger during WSRS than before. Average aerial mixing rates before and during WSRS were 50 ± 26 km2 d-1 and 89 ± 51 km2 d-1, respectively. (3) Our data is consistent with P limitation and suggest that stoichiometrically based P limitation was even more severe during WSRS. (4) All river-derived nutrients were thoroughly consumed within one to two weeks after entry to near-shore waters. (5) The extent of the area influenced by terrestrial nutrients was two to three times greater during WSRS. Human influence, such as triggered by WSRS regulations, should thus be considered when studying biogeochemical processes and nutrient budgets in situations like the Yellow River estuary.

  18. What is the Main Potential Factor Influencing Ocular Protrusion?

    PubMed Central

    Li, Yinwei; Su, Yun; Song, Xuefei; Zhou, Huifang; Fan, Xianqun

    2017-01-01

    Background The aim of the present study was to establish the normal-range orbital parameters and to explore the relationships between ocular protrusion and various orbital morphological factors. Material/Methods A retrospective, non-comparative case series was conducted from January 2014 to December 2015. We recruited 56 subjects (112 orbits), including 27 males (21 to 87 years of age) and 29 females (22 to 88 years of age) in this study. Nine length measurements, 2 angle measurements, and 2 volume measurements of various aspects of the orbit were obtained using Mimics v18.0 software. The data were collected manually using a 3D measurement technique. Statistical analyses using t tests and Pearson’s correlation analyses were performed to evaluate the differences and relationships between the parameters, respectively. Results Ocular protrusion in both sexes was closely related to the following values: orbital soft tissue volume (OSTV) (males: r=0.61, p<0.001; females: r=0.39, p=0.003), orbital soft tissue volume/bony orbital volume (OSTV/BOV) (males: r=0.90, p<0.001; females: r=0.87, p<0.001), orbital width (males: r=0.40, p=0.003; females: r=0.53, p<0.001), orbital height (males: r=0.29, p=0.038; females: r=0.45, p<0.001), and globe diameter (males: r=0.52, p<0.001; females: r=0.48, p<0.001). No differences were found between the right and left orbits. Conclusions The study provides insight into the potential factors that influence ocular protrusion, which include the OSTV/BOV ratio, the shape of the orbital aperture, and the ocular axial length. The results of orbital surgery can be made more predictable by accounting for these 3 factors. The database and regression formula might provide support for surgical planning in the future. PMID:28053301

  19. The influence of morphology on geldanamycin production in submerged fermentations of Streptomyces hygroscopicus var. geldanus.

    PubMed

    Dobson, Lynne F; O'Cleirigh, Cormac C; O'Shea, Daniel G

    2008-07-01

    The diverse morphology of the filamentous organism Streptomyces hygroscopicus var. geldanus was characterised by image analysis under various environmental conditions. In the presence of surfactant compounds, a significant decrease in the mean pellet diameter was observed. Cell aggregation was also influenced by spore inoculum level, with high concentrations reducing pellet size. In addition, the dispersion of pellets was found to increase with the inclusion of glass beads to submerged shake-flask cultures. In all cases, production of the secondary metabolite geldanamycin was determined to be dependent on the morphological profile of the organism, with a concomitant increase of 88% in geldanamycin yield observed as the mean pellet diameter was reduced by 70%. Thus, to maximise the yield of geldanamycin, it is necessary to limit pellet formation in Streptomyces hygroscopicus var. geldanus to an appropriate size.

  20. Influence of carbon fillers nature on the structural and morphological properties of polyurethane-based composites

    NASA Astrophysics Data System (ADS)

    Melentyev, S. V.; Malinovskaya, T. D.; Pavlov, S. V.

    2016-01-01

    The present paper is devoted to studying structural and morphological properties of the resistive composite materials based on the polyurethane binder. The paper shows the influence of nature, size, shape, concentration of conductive carbon fillers (channel black K-163, graphite element GE-3, colloidal-graphite preparation C-1) and the method of their introduction into the binder to form the electrical conductivity of composites. Experimentally it was found out that a homogeneous composite structure reaches dispersive mixing filler and binder within 120 min. The analysis of the morphological pattern surfaces and chipping resistance materials has demonstrated that composites with colloidal-graphite preparation C-1 are more unimodal with the same concentrations of the investigated fillers.

  1. Influence of collagen addition on the thermal and morphological properties of chitosan/xanthan hydrogels.

    PubMed

    Horn, Marilia M; Martins, Virginia C A; Plepis, Ana Maria de Guzzi

    2015-09-01

    This study investigates the collagen influence on thermal and morphological characteristics of chitosan/xanthan hydrogels for potential tissue engineering applications. Anionic collagen was prepared by selective hydrolysis of type I collagen found in bovine tendons. Chitosan was obtained from the partial deacetylation of squid pen β-chitin and xanthan was acquired from Fluka. The hydrogels were obtained in different ratios and were characterized by thermal and morphological analysis. FT-IR suggested only electrostatic interactions between NH3(+) groups of chitosan and COO(-) groups of xanthan and collagen. Thermogravimetric curves showed that hydrogels contain a great amount of water (above 98%) and the presence of collagen does not change this characteristic. Freezing-bound water transition in DSC curves was shifted to higher values due to the increase of water/polymer interaction, mainly when different ratios of chitosan and xanthan were used. SEM images showed sheet-form structures with the presence of collagen promoting an increase in pore size.

  2. The Modeling of Factors That Influence Coast Guard Manpower Requirements

    DTIC Science & Technology

    2014-12-01

    FACTORS THAT INFLUENCE COAST GUARD MANPOWER REQUIREMENTS by Kara M. Lavin December 2014 Thesis Advisor: Ronald E. Giachetti Co-Advisor...AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE THE MODELING OF FACTORS THAT INFLUENCE COAST GUARD MANPOWER REQUIREMENTS 5. FUNDING...200 words) This research, conducted at the request of the United States Coast Guard Manpower Requirements Determination Division, determines the

  3. Marketing Factors Influencing the Overall Satisfaction of Marriage Education Participants.

    ERIC Educational Resources Information Center

    Morris, Michael Lane; Cooper, Catherine; Gross, Kevin H.

    1999-01-01

    Seventy-one married couples attending marriage education workshops were surveyed regarding price, product, place, people, and promotional marketing factors influencing their overall satisfaction as workshop participants. Findings suggest both similar and unique marketing factors influenced husbands' and wives' satisfaction. Recommendations for…

  4. Growth factor signaling alters the morphology of the zebrafish ethmoid plate.

    PubMed

    Cusack, Brian J; Parsons, Trish E; Weinberg, Seth M; Vieira, Alexandre R; Szabo-Rogers, Heather L

    2017-02-28

    Craniofacial development relies on coordinated tissue interactions that allow for patterning and growth of the face. We know a priori that the Wingless, fibroblast growth factor, Hedgehog and transforming growth factor-beta growth factor signaling pathways are required for the development of the face, but how they contribute to the shape of the face is largely untested. Here, we test how each signaling pathway contributes to the overall morphology of the zebrafish anterior neurocranium. We tested the contribution of each signaling pathway to the development of the ethmoid plate during three distinct time periods: the time of neural crest migration [10 hour post fertilization (hpf)]; once the neural crest is resident in the face (20 hpf); and finally at the time at which the cartilaginous condensations are being initiated (48 hpf). Using geometric morphometric analysis, we conclude that each signaling pathway contributes to the shape, size and morphology of the ethmoid plate in a dose-, and time-dependent fashion.

  5. Influence of botanic origin and amylose content on the morphology of starch nanocrystals

    NASA Astrophysics Data System (ADS)

    LeCorre, Déborah; Bras, Julien; Dufresne, Alain

    2011-12-01

    Starch nanocrystals (SNC) are crystalline platelets resulting from the disruption of the semi-crystalline structure of starch granules by the acid hydrolysis of amorphous parts. The aim of this study was to assess the influence of botanic origin and amylose content of native starches on the morphology and properties of resulting nanoparticles. SNC were prepared from five different starches normal maize, high amylose maize, waxy maize, potato, and wheat; covering three botanic origins, two crystalline types, and three range of amylose content (0, 25, and 70%) for maize starch. Different types of nanocrystals were obtained with a thickness ranging between 4 and 8 nm and diameter from about 50 to 120 nm depending on the source. The comparison of their morphology, crystallinity, and rheological properties is proposed for the first time. For the same amylose content, maize, potato, and wheat resulted in rather similar size and crystallinity of SNC proving the limited influence of the botanic origin. For the same botanic origin (maize), differences in size were more important indicating the influence of the amylopectin content. Also, particles tended to show square shapes with increasing native starch's amylopectin content and A-type crystalinity. Thus, only high amylose content starches should be avoided to prepare SNC.

  6. Chondrocyte Morphology in Stiff and Soft Agarose Gels and the Influence of Fetal Calf Serum.

    PubMed

    Karim, Asima; Hall, Andrew C

    2017-05-01

    Changes to chondrocyte volume/morphology may have deleterious effects on extracellular matrix (ECM) metabolism potentially leading to cartilage deterioration and osteoarthritis (OA). The factors controlling chondrocyte properties are poorly understood, however, pericellular matrix (PCM) weakening may be involved. We have studied the density, volume, morphology, and clustering of cultured bovine articular chondrocytes within stiff (2% w/v) and soft (0.2% w/v) three-dimensional agarose gels. Gels with encapsulated chondrocytes were cultured in Dulbecco's Modified Eagle's Medium (DMEM; fetal calf serum (FCS) 1-10%;380 mOsm) for up to 7 days. Chondrocytes were fluorescently labeled after 1, 3, and 7 days with 5-chloromethylfluorescein-diacetate (CMFDA) and propidium iodide (PI) or 1,5-bis{[2-(di-methylamino)ethyl]amino}-4,8-dihydroxyanthracene-9,10-dione (DRAQ5) to identify cytoplasmic space or DNA and imaged by confocal laser scanning microscopy (CLSM). Chondrocyte density, volume, morphology, and clustering were quantified using Volocity™ software. In stiff gels after 7 d with 10% FCS, chondrocyte density remained unaffected and morphology was relatively normal with occasional cytoplasmic processes. However, in soft gels by day 1, chondrocyte volume increased (P = 0.0058) and by day 7, density increased (P = 0.0080), along with the percentage of chondrocytes of abnormal morphology (P < 0.0001) and enhanced clustering (P < 0.05), compared to stiff gels. FCS exacerbated changes to density (P < 0.01), abnormal morphology (P < 0.001) and clustering (P < 0.01) compared to lower concentrations at the same gel strength. Reduced gel stiffness and/or increased FCS concentrations promoted chondrocyte proliferation and clustering, increased cell volume, and stimulated abnormal morphology, producing similar changes to those occurring in OA. The increased penetration of factors in FCS into soft gels may be important in the development of

  7. Spatial variability of factors influencing coastal change in the Western Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Manson, G. K.; Solomon, S. M.; Forbes, D. L.; Atkinson, D. E.; Craymer, M.

    2005-06-01

    Coastal change in the western Canadian Arctic is influenced by coastal morphology, relative sea-level trend and sea-ice and storm climates. The spatial variability of these factors tends to follow general east west trends suggesting similar trends in coastal erosion hazard, processes and rates of coastal change. The spatial variability in the causes of coastal change is examined in the communities of Tuktoyaktuk, Sachs Harbour, Holman and Kugluktuk.

  8. Factors Influencing Career Choice among Police Recruits

    ERIC Educational Resources Information Center

    Cole, Bryan

    2012-01-01

    This quantitative, non-experimental study examined the career choice factors of 154 (n = 154) police recruits to determine a correlation of age group generation to the five career choice factors presented in the Sibson Reward of Work Model. Law enforcement agencies faced a shortage of viable candidates to fill vacant positions. While extensive…

  9. COX assembly factor ccdc56 regulates mitochondrial morphology by affecting mitochondrial recruitment of Drp1.

    PubMed

    Ban-Ishihara, Reiko; Tomohiro-Takamiya, Shiho; Tani, Motohiro; Baudier, Jacques; Ishihara, Naotada; Kuge, Osamu

    2015-10-07

    Mitochondria are dynamic organelles that alter their morphology in response to cellular signaling and differentiation through balanced fusion and fission. In this study, we found that the mitochondrial inner membrane ATPase ATAD3A interacted with ccdc56/MITRAC12/COA3, a subunit of the cytochrome oxidase (COX)-assembly complex. Overproduction of ccdc56 in HeLa cells resulted in fragmented mitochondrial morphology, while mitochondria were highly elongated in ccdc56-repressed cells by the defective recruitment of the fission factor Drp1. We also found that mild and chronic inhibition of COX led to mitochondrial elongation, as seen in ccdc56-repressed cells. These results indicate that ccdc56 positively regulates mitochondrial fission via regulation of COX activity and the mitochondrial recruitment of Drp1, and thus, suggest a novel relationship between COX assembly and mitochondrial morphology.

  10. Factors Influencing Curricular Reform; An Irish Perspective

    ERIC Educational Resources Information Center

    Ferris, Helena; Joyce, Pauline

    2015-01-01

    There are various influences and obstacles when planning an educational curriculum. The imprint of globalisation on the landscape of Irish medicine highlights the importance of delivering a diverse curriculum with international dimensions so that knowledge and skills can transfer across borders. It is also clear that medical emigration has a…

  11. FACTORS INFLUENCING FRICTION OF PHOSPHATE COATINGS,

    DTIC Science & Technology

    surface roughness, crystalline structure , and velocity. The coefficients of friction for manganese phosphate coatings did not differ to any practical...The coefficient of friction was independent of the applied load. Velocity during dynamic testing, surface finish, and crystalline structure influenced

  12. Effect of childhood maltreatment and brain-derived neurotrophic factor on brain morphology

    PubMed Central

    Schmaal, Lianne; Jansen, Rick; Milaneschi, Yuri; Opmeer, Esther M.; Elzinga, Bernet M.; van der Wee, Nic J. A.; Veltman, Dick J.; Penninx, Brenda W. J. H.

    2016-01-01

    Childhood maltreatment (CM) has been associated with altered brain morphology, which may partly be due to a direct impact on neural growth, e.g. through the brain-derived neurotrophic factor (BDNF) pathway. Findings on CM, BDNF and brain volume are inconsistent and have never accounted for the entire BDNF pathway. We examined the effects of CM, BDNF (genotype, gene expression and protein level) and their interactions on hippocampus, amygdala and anterior cingulate cortex (ACC) morphology. Data were collected from patients with depression and/or an anxiety disorder and healthy subjects within the Netherlands Study of Depression and Anxiety (NESDA) (N = 289). CM was assessed using the Childhood Trauma Interview. BDNF Val66Met genotype, gene expression and serum protein levels were determined in blood and T1 MRI scans were acquired at 3T. Regional brain morphology was assessed using FreeSurfer. Covariate-adjusted linear regression analyses were performed. Amygdala volume was lower in maltreated individuals. This was more pronounced in maltreated met-allele carriers. The expected positive relationship between BDNF gene expression and volume of the amygdala is attenuated in maltreated subjects. Finally, decreased cortical thickness of the ACC was identified in maltreated subjects with the val/val genotype. CM was associated with altered brain morphology, partly in interaction with multiple levels of the BNDF pathway. Our results suggest that CM has different effects on brain morphology in met-carriers and val-homozygotes and that CM may disrupt the neuroprotective effect of BDNF. PMID:27405617

  13. Pangolin expression influences the development of a morphological novelty: beetle horns.

    PubMed

    Wasik, Bethany R; Moczek, Armin P

    2012-05-01

    Morphological diversity arises during development through the actions and interactions of diverse developmental pathways. Among those, the Wnt pathway is known to contribute to diverse developmental processes such as segmentation and the morphogenesis of appendages. Here, we characterize a transcription factor in the Wnt pathway, pangolin (pan), to investigate the role of Wnt signaling in the development of evolutionarily novel body structures: the horns of beetles. Beetle horns are highly diverse in size, shape, and number and develop principally from two major body regions: the head and prothorax. We investigate horns in two species of the genus Onthophagus using comparative in situ hybridization, larval RNA interference, and allometric measurements to analyze whether horn formation is regulated by pan and by extension the Wnt pathway. Our results illustrate that pan expression affects beetle horn growth in a species-, sex-, and location-specific manner in two morphologically distinct, yet closely-related, Onthophagus species.

  14. The influence of slope on Spartium junceum root system: morphological, anatomical and biomechanical adaptation.

    PubMed

    Lombardi, Fabio; Scippa, G S; Lasserre, B; Montagnoli, A; Tognetti, R; Marchetti, M; Chiatante, D

    2017-03-15

    Root systems have a pivotal role in plant anchorage and their mechanical interactions with the soil may contribute to soil reinforcement and stabilization of slide-prone slopes. In order to understand the responses of root system to mechanical stress induced by slope, samples of Spartium junceum L., growing in slope and in plane natural conditions, were compared in their morphology, biomechanical properties and anatomical features. Soils sampled in slope and plane revealed similar characteristics, with the exception of organic matter content and penetrometer resistance, both higher in slope. Slope significantly influenced root morphology and in particular the distribution of lateral roots along the soil depth. Indeed, first-order lateral roots of plants growing on slope condition showed an asymmetric distribution between up- and down-slope. Contrarily, this asymmetric distribution was not observed in plants growing in plane. The tensile strength was higher in lateral roots growing up-slope and in plane conditions than in those growing down-slope. Anatomical investigations revealed that, while roots grown up-slope had higher area covered by xylem fibers, the ratio of xylem and phloem fibers to root diameter did not differ among the three conditions, as also, no differences were found for xylem fiber cell wall thickness. Roots growing up-slope were the main contributors to anchorage properties, which included higher strength and higher number of fibers in the xylematic tissues. Results suggested that a combination of root-specific morphological, anatomical and biomechanical traits, determines anchorage functions in slope conditions.

  15. Silver nanoparticles: Influence of the temperature synthesis on the particles’ morphology

    NASA Astrophysics Data System (ADS)

    Piñero, S.; Camero, S.; Blanco, S.

    2017-01-01

    Silver nanoparticles have a wide range of applications in the medical field, textile and food industries. These and other applications can be found due to the relation between its size and morphology. In this study the influence of bath temperature on the morphology and size of silver nanoparticles are evaluated, which are obtained by chemical reduction of AgNO3 using three reducing agents: sodium borohydride, ascorbic acid and sodium citrate. The evaluation carried out by the traditional UV-vis Spectrophotometric analysis and with High Resolution Transmission Electron Microscopy. The UV-vis spectrum of the silver colloids obtained by chemical reduction using three different reducing agents shows the effect of the temperature change on the growing and aggregative process. The final effect on the morphology, size and aggregation of the particles was confirmed by TEM. The result suggests a change in the growing mechanism, conducted by aggregation of atoms at 5 and 20°C degrees and aggregation of clusters at higher temperatures. Moreover in this work the main synthesis methods of nanomaterials are described.

  16. Growth Hormone Influence on the Morphology and Size of the Mouse Meibomian Gland

    PubMed Central

    Liu, Yang; Knop, Erich; Knop, Nadja; Sullivan, David A.; List, Edward O.; Kopchick, John J.; Kam, Wendy R.; Ding, Juan

    2016-01-01

    Purpose. We hypothesize that growth hormone (GH) plays a significant role in the regulation of the meibomian gland. To test our hypothesis, we examined the influence of GH on mouse meibomian gland structure. Methods. We studied four groups of mice, including (1) bovine (b) GH transgenic mice with excess GH; (2) GH receptor (R) antagonist (A) transgenic mice with decreased GH; (3) GHR knockout (−/−) mice with no GH activity; and (4) wild type (WT) control mice. After mouse sacrifice, eyelids were processed for morphological and image analyses. Results. Our results show striking structural changes in the GH-deficient animals. Many of the GHR−/− and GHA meibomian glands featured hyperkeratinized and thickened ducts, acini inserting into duct walls, and poorly differentiated acini. In contrast, the morphology of WT and bGH meibomian glands appeared similar. The sizes of meibomian glands of bGH mice were significantly larger and those of GHA and GHR−/− mice were significantly smaller than glands of WT mice. Conclusions. Our findings support our hypothesis that the GH/IGF-1 axis plays a significant role in the control of the meibomian gland. In addition, our data show that GH modulates the morphology and size of this tissue. PMID:26981277

  17. The potential influence of morphology on the evolutionary divergence of an acoustic signal

    PubMed Central

    Pitchers, W. R.; Klingenberg, C.P.; Tregenza, Tom; Hunt, J.; Dworkin, I.

    2014-01-01

    The evolution of acoustic behaviour and that of the morphological traits mediating its production are often coupled. Lack of variation in the underlying morphology of signalling traits has the potential to constrain signal evolution. This relationship is particularly likely in field crickets, where males produce acoustic advertisement signals to attract females by stridulating with specialized structures on their forewings. In this study, we characterise the size and geometric shape of the forewings of males from six allopatric populations of the black field cricket (Teleogryllus commodus) known to have divergent advertisement calls. We sample from each of these populations using both wild-caught and common-garden reared cohorts, allowing us to test for multivariate relationships between wing morphology and call structure. We show that the allometry of shape has diverged across populations. However, there was a surprisingly small amount of covariation between wing shape and call structure within populations. Given the importance of male size for sexual selection in crickets, the divergence we observe among populations has the potential to influence the evolution of advertisement calls in this species. PMID:25223712

  18. Influence of transbilayer area asymmetry on the morphology of large unilamellar vesicles.

    PubMed Central

    Mui, B L; Döbereiner, H G; Madden, T D; Cullis, P R

    1995-01-01

    The morphological consequences of differences in the monolayer surface areas of large unilamellar vesicles (LUVs) have been examined employing cryoelectron microscopy techniques. Surface area was varied by inducing net transbilayer transport of dioleoylphosphatidylglycerol (DOPG) in dioleoylphosphatidylcholine (DOPC):DOPG (9:1, mol:mol) LUVs in response to transmembrane pH gradients. It is shown that when DOPG is transported from the inner to the outer monolayer, initially invaginated LUVs are transformed to long narrow tubular structures, or spherical structures with one or more protrusions. Tubular structures are also seen in response to outward DOPG transport in DOPC:DOPG:Chol (6:1:3, mol:mol:mol) LUV systems, and when lyso-PC is allowed to partition into the exterior monolayer of DOPC:DOPG (9:1, mol:mol) LUVs in the absence of DOPG transport. Conversely, when the inner monolayer area is expanded by the transport of DOPG from the outer monolayer to the inner monolayer of non-invaginated LUVs, a reversion to invaginated structures is observed. The morphological changes are well described by an elastic bending theory of the bilayer. Identification of the difference in relaxed monolayer areas and of the volume-to-area ratio of the LUVs as the shape-determining factors allows a quantitative classification of the observed morphologies. The morphology seen in LUVs supports the possibility that factors leading to differences in monolayer surface areas could play important roles in intracellular membrane transport processes. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 PMID:8519993

  19. Influence of Nutritional Factors on Lipid Metabolism.

    DTIC Science & Technology

    1980-12-01

    conditions of chronic high level fat oxidation such as exercise, Askew et al. (121) fed exercising rats diets supplemented with 0.5Z L- carnitine . Although...exercise increased adipose tissue fatty acid turnover, supplemental dietary carnitine neither increased skeletal muscle in vitro fatty acid oxidation...some investigators believe the relative activities of the sn-glycerolphosphate acyltransferase and carnitine palmttyltrans- ferase may influence the

  20. Choice of treatment with antidepressants: influencing factors.

    PubMed

    Himmerich, Hubertus; Wranik, Dominika W

    2012-01-01

    Depressive disorders place a large burden on patients and on society. Although efficacious treatment options for unipolar depressive disorders exist, substantial gaps in care remain. In part, the challenge lies in the matching of individual patients with appropriate care. This is complicated by the steady increases in the variety of antidepressants available in the market. The goal of this study is to highlight the decision processes in the selection of antidepressants by clinicians, given that most treatments have similar clinical effectiveness profiles. We conducted a systematic literature review of studies that referred to the decisions surrounding treatment with antidepressants for the treatment of non-psychotic unipolar depression. Our analysis of the literature reveals that the choice of treatment is based on a variety of factors, of which clinical evidence is only one. These factors can be categorized into clinical factors such as illness and treatment characteristics, individual factors such as patient and physician characteristics, and contextual factors such as setting characteristics, decision supports and pharmacoeconomic aspects. Illness characteristics are defined by the type and severity of depression. Treatment characteristics include drug properties, efficacy, effectiveness and favorable as well as unintended adverse effects of the drug. Examples for patient characteristics are co-morbidities and individual preferences, and physician characteristics include knowledge, experience, values and beliefs, and the relationship with the patient. Treatment guidelines, algorithms, and most recently, computational supports and biological markers serve as decision supports.

  1. Behavioral, Attitudinal, and Cultural Factors Influencing Interagency Information Sharing

    DTIC Science & Technology

    2011-05-01

    U.S. Army Research Institute for the Behavioral and Social Sciences Research Report 1944 Behavioral, Attitudinal, and Cultural Factors...REPORT TYPE Final 3. DATES COVERED (from... to) June 2008 - November 2009 4. TITLE AND SUBTITLE Behavioral, Attitudinal, and Cultural Factors...examined factors influencing interagency information sharing. Findings suggest that organizational culture , attitudes toward information sharing, perceived

  2. Secondary factors influencing cascade damage formation

    NASA Astrophysics Data System (ADS)

    Stoller, Roger E.; Guiriec, Sylvain G.

    2004-08-01

    Primary cascade damage production in iron has been extensively investigated by molecular dynamics, and the average defect production as a function of cascade energy and temperature is well characterized. However, preliminary results indicate several factors alter `normal' cascade evolution, leading to quite different defect production behavior. Further investigation of three such factors has been carried out: (1) primary knock-on atom (PKA) direction, (2) nearby free surfaces, and (3) pre-existing effects. Results of the investigation confirm these factors significantly impact damage production. Effects include: enhanced defect survival for PKA directions lying in close-packed {1 1 0} planes, increased point defect clustering and larger defect clusters in cascades initiated near a surface, and reduced defect survival in material containing defects. The origin and implications of these effects are discussed relative to the interpretation of certain experimental observations and parameters used in other modeling studies.

  3. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences

    PubMed Central

    Oliveira, Luiz Flamarion B.

    2015-01-01

    foot of male leopard cats is the main feature of sexual dimorphism among P. b. bengalensis (and probably among P. b. horsfieldii too). External body measurements also indicated the absence of sexual dimorphism among individuals of P. b. borneoensis. Inter-subspecific skull comparisons provided a morphometric basis for differentiating some subspecies. Prionailurus b. horsfieldii and P. b. bengalensis were distinguished only by a subtle difference in PM4 size, indicating that overall skull morphology does not appear to support their separate taxonomical status, in spite of the marked differences reported in their coat patterns. Geological events affecting the Sunda Shelf connection between the Sunda Islands and the mainland during the Last Glacial Maximum seem to have influenced directly the morphological pattern shown by leopard cat subspecies nowadays. PMID:26500818

  4. The influence of slope morphology on gullies: Terrestrial gullies in Lake George as analogues for Mars

    NASA Astrophysics Data System (ADS)

    Hobbs, S. W.; Paull, D. J.; Clarke, J. D. A.

    2013-06-01

    Terrestrial gullies provide a useful benchmark to compare martian gully forms against. We compare pole and equator facing gullies in an unnamed crater located in the martian southern mid-latitudes with gullies located on the Lake George escarpment south of Gearys Gap, New South Wales, Australia. Our investigations showed gully morphology at both sites is greatly influenced by thickness of readily erodable regolith, local slope and the presence or absence of bedrock exposures in the gullies. We found that the martian pole-facing gullies are the most similar to those of Lake George and both systems are therefore likely to have been eroded by liquid water. Although the martian gullies possessed much greater volumes of eroded sediment, they had not eroded to underlying bedrock. This contrasts with the smaller Lake George gully channels where numerous bedrock exposures, observed during our survey, affected their slope and overall morphology. Similarly, although dominated by dry processes, multiple bedrock exposures are present within the equator facing martian gullies affecting their cross sectional area and hence sediment transport. The studied sites all showed significant influence from initial slope angles, indicating that interpretation of gully forms such as slopes below the angle of repose, curved profiles and sinuosity must be placed in context of local environments. This analysis can be applied to other regions of Mars and Earth and provide a greater understanding of how geomorphologic processes operate on both worlds.

  5. Influence of Morphology on Electrical Properties of Syndiotactic Polypropylene Compared with Those of Isotactic Polypropylene

    NASA Astrophysics Data System (ADS)

    Kim, Dong; Yoshino, Katsumi; Inoue, Takeo; Abe, Masaru; Uchikawa, Nobutaka

    1999-06-01

    The influence of morphology on the electrical properties of syndiotactic polypropylene (sPP) has been investigated in comparison with those of conventional isotactic polypropylene (iPP). The evolution of spherulite in sPP occurred at a lower temperature than in iPP, and the size of spherulites in sPP is much smaller than those of iPP, though the number of spherulites increases drastically. The influence of heat treatment on the electrical properties of sPP, such as conductivity and current density-electric field characteristics, is negligible in contrast to iPP, in which the conductivity increased drastically and breakdown strength decreased markedly due to growth of large spherulites upon heat treatment. These results are discussed in terms of morphological change upon heat treatment. As a result, sPP is confirmed to be an excellent candidate for a new insulating polymer for cables which can be used at a much higher operating temperature than that of widely used cables with cross-linked polyethylene (XLPE) (90°C), because of its thermal stability, stable electrical properties even following heating treatment and mechanical flexibility due to the small spherulite size and low crystallinity under any preparation and treatment conditions.

  6. Assessing Morphological Changes due to Hydrometeorologic Influences in Mehendiganj Island, Meghna Estuary, Bangladesh

    NASA Astrophysics Data System (ADS)

    Hossain, A.; Ahmed, K. M.; Overeem, I.; Rogers, K. G.

    2014-12-01

    The Ganges-Brahmaputra-Meghna river system is the largest river system in the world with massive discharge rates and sediment loads (annually over one billion tons). Sediment from these rivers has formed one of the largest and most densely populated deltas in the world. The combined rivers discharge through the Meghna estuary into the Bay of Bengal. The study area, Mehendiganj Island, is located in the morphologically dynamic Meghna estuary region of the delta and is characterized by rapid accretion and erosion. The net effect of erosion-accretion processes between the years 1987-2012 was analyzed using Landsat satellite imagery. Time-lapse series were generated over consecutive monsoon periods to estimate net erosion, and reveal that morphological changes are influenced by hydrological conditions (e.g. areal extent of flooding surface, hydrometeorology) driven by high river and sediment discharge, mainly during the seasonal monsoon (wet) period. The hydrological conditions and, consequently, the morphological changes exhibit a skewed pattern in annual distribution on account of high-energy condition prevailing during the monsoon. Total erosion and accretion within the study area was estimated to be about 5997 hectares and 2922 hectares, respectively. The measured annual erosion rates were as high as 1493 hectares, which were about 15% of the existing land surface within the study area. Discharge rates and sediment loads over the course of the study period were calculated using a numerical model (WBMsed) and was validated by comparisons with field-measured values. Moreover, hydrological parameters were analyzed in the context of statistical hydrology in order to obtain trends and were correlated with annual accretion and erosion rates attained from the satellite image analysis. Anomalies in the patterns of annual accretion and erosion rates were detected during extreme hydrometeorological events such as high floodwater years and cyclones. The morphological changes

  7. Factors Influencing Young People's Conceptions of Environment.

    ERIC Educational Resources Information Center

    Loughland, Tony; Reid, Anna; Walker, Kim; Petocz, Peter

    2003-01-01

    Explains the importance of environmental education in schools for achieving environmental protection and improvement. Statistically examines factors that incline students to a 'relation' rather than an 'object' conception of the environment. Concludes that development of the former would seem to be an important aim of environmental education and…

  8. Factors Influencing uUniversity Research Performance

    ERIC Educational Resources Information Center

    Edgar, Fiona; Geare, Alan

    2013-01-01

    This research extends our understanding of research productivity by examining features of managerial practice and culture within university departments. Adopting a robust comparative research design, capturing both interview and survey data sourced from multiple stakeholders from New Zealand universities, we seek to identify factors associated…

  9. The Influence of Noneconomic Factors on Negotiators

    ERIC Educational Resources Information Center

    Tracy, Lane

    1974-01-01

    Certain noneconomic factors in collective bargaining are directly related to the negotiator's personal inclination to settle for the new contract. In this study, the pattern of relationships between the parties, the nature of the work itself, favorable recognition, team policy, and interpersonal relationships proved to be significantly related to…

  10. Factors influencing nurses' participation in clinical research.

    PubMed

    Jacobson, Ann F; Warner, Andrea M; Fleming, Eileen; Schmidt, Bruce

    2008-01-01

    Clinical research is necessary for developing nursing's body of knowledge and improving the quality of gastroenterology nursing care. The support and participation of nursing staff are crucial to conducting interventional research. Identification of characteristics of nurses and their work settings that facilitate or impede participation in research is needed. The purpose of this descriptive correlational study was to examine the effect of personal and professional characteristics and attitudes about nursing research on staff nurses' participation in a clinical nursing research project. A questionnaire measuring nurses' attitudes, perceptions of availability of support, and research use was distributed to staff nurses working on an endoscopy lab and two same-day surgery units where a nursing research study had recently been conducted. Investigator-developed items measured nurses' attitudes about the utility and feasibility of the interventions tested in the original study. A total of 36 usable questionnaires comprised the sample. Factor analysis of the two questionnaires resulted in three-factor (Importance of Research, Interest in Research, and Environment Support of Research) and two-factor (Value of Cognitive-Behavioral Interventions [CBIs] and Participation in Study) solutions, respectively. There were no statistically significant differences in mean scores for the five factors between nurses who did (n = 19) and those who did not (n = 17) participate in the original study. The Participation in Research Factor was significantly negatively correlated with years in nursing (r = -.336, p < .05) and positively correlated with the importance of research factor (r = .501, p < .01). Importance of research was negatively correlated with years in nursing (r = -.435, p < .01) and positively correlated with value of CBI (r = .439, p < .01) and participation in study (r = .501, p < .01). Findings from the study will contribute to the body of knowledge about factors that

  11. Influence of genetic and environmental factors on oral diseases and function in aged twins.

    PubMed

    Kurushima, Y; Ikebe, K; Matsuda, K; Enoki, K; Ogata, S; Yamashita, M; Murakami, S; Hayakawa, K; Maeda, Y

    2015-01-01

    This study was conducted to quantify the genetic and environmental contributions to oral disease and function in twins. Participants were middle-aged and old twins, 116 monozygotic and 16 dizygotic pairs whose mean age was 66·1 ± 10·3 (SD) years. Number of teeth, percentage of decayed, filled and missing teeth and periodontal status were recorded as indicators of oral disease. The widths of upper and lower dental arch served as indicators of morphological figures. Furthermore, stimulated salivary flow rate, occlusal force and masticatory performance were measured as indicators of oral function. Univariate genetic analysis with monozygotic and dizygotic twin pairs was conducted to detect the fittest structural equation model of each outcome. Both number of teeth and periodontal status fitted the model composed of common environmental factor and unique environmental factor. Decayed, filled and missing teeth, morphological figures and measurements of oral function fitted the model composed of additive genetic factor and unique environmental factor. The model fitting of each measurement suggested that periodontal disease was mainly affected by environmental factors, while morphological figures and oral functions were influenced by both genetic and environmental factors.

  12. Influence of laser irradiating energy on optical properties and morphology of TiO2 films

    NASA Astrophysics Data System (ADS)

    Guo, Fang; Xu, Junqi; Su, Junhong; Dang, Shaokun

    2013-12-01

    The optical thin film parts are important components used in the laser systems. In practice, the electromagnetic field generated by the laser will make complex and diverse changes on the films, but the fundamental related with properties changing is not clear. For the purpose of recognizing the variation of TiO2 films irradiated by the laser, TiO2 films were prepared on K9 substrates at the same experimental conditions with the exception that the irradiating laser energy was different to investigate effects about the film's properties and morphology between the before and after irradiation. The following film's factors: transmittance, refractive index, extinction coefficient, film thickness and laser-induced damage threshold (LIDT) are included in experimental results, also, morphology and roughness by an Atomic Force Microscope (AFM) and a Taylor Surf CCI 2000 non-contact instrument are needed. The result showed that irradiating laser can decrease TiO2 films' transmittance and roughness, and increases the films' refractive index and LIDT. Furthermore, the results indicated that different laser energy cause the different morphology of films.

  13. Factors influencing medication label viewing in Malaysia.

    PubMed

    Cheah, Yong Kang; Chong, Yen Wan

    2016-07-12

    The misuse of medicine is a serious public health issue worldwide. An important factor that contributes to the misuse of medicine is the lack of medication label viewing by consumers. The objective of the present study is to examine the socio-economic, demographic and lifestyle factors associated with medication label viewing among Malaysian adults. The empirical analysis is based on a nationally representative data set of 30,992 respondents. An ordered probit model is used to examine different types of medication label viewers. The results of this study suggest that socio-economic (i.e. age, income level, education level, location of residence), demographic (i.e. gender, ethnicity, marital status) and lifestyle factors (i.e. physical activity, smoking) have significant effects on medication label viewing. It is found that age, low-income and low-education level reduce the likelihood of viewing medication label. Based on these findings, several policy implications are suggested. The present study provides policy makers with baseline information regarding which cohorts of individuals to focus on in efforts to increase the frequency of medication label viewing.

  14. Influence of flow regime and channel morphology on larval drift and dispersion in a large regulated river

    NASA Astrophysics Data System (ADS)

    Erwin, S.; Jacobson, R. B.

    2013-12-01

    Larval drift is a critical phase of ontogenetic development for many species of lotic fishes. Downstream advection and dispersion of passively drifting larvae or eggs is controlled by the complex interaction of flow regime, channel planform, local channel morphology, and the resulting hydraulic gradients. In many regulated rivers, channel engineering and perturbations to the flow regime may disrupt natural drift processes and impact successful recruitment of native fishes. Here we explore the influence of flow regime and channel morphology on the downstream transport, dispersion, and retention of Pallid Sturgeon larvae, an endangered species endemic to the Mississippi River basin and the focus of significant conservation effort on the Missouri River. The transition from drifting free embryo to exogenously feeding larvae has been identified as a potential life stage bottleneck for the Pallid Sturgeon. Previous studies have indicated that river regulation and fragmentation may contribute to mortality of larval Pallid Sturgeon by reducing the extent of free-flowing river required by free embryos to complete the transition to exogenous feeding. Additionally, channelization may have increased the rate at which larvae are advected downstream out of the Missouri River basin. We describe the complex interactions and influence of morphologic and hydraulic factors on larval drift using an extensive library of hydroacoustic data collected along more than 1300 km of the Lower Missouri River. We use a one-dimensional advection-dispersion model to estimate total drift distance and employ the longitudinal dispersion coefficient as a measure to quantify the tendency towards dispersion or retention of passively drifting larvae in geomorphically distinct segments of river. We use a two-dimensional hydrodynamic model to evaluate the sensitivity of drift and dispersion to in-channel navigation structures and flood hydrology. Based on insights gained from the analysis of field data and

  15. Influence of effective number of pulses on the morphological structure of teeth and bovine femur after femtosecond laser ablation.

    PubMed

    Nicolodelli, Gustavo; Lizarelli, Rosane de Fátima Zanirato; Bagnato, Vanderlei Salvador

    2012-04-01

    Femtosecond lasers have been widely used in laser surgery as an instrument for contact-free tissue removal of hard dental, restorative materials, and osseous tissues, complementing conventional drilling or cutting tools. In order to obtain a laser system that provides an ablation efficiency comparable to mechanical instruments, the laser pulse rate must be maximal without causing thermal damage. The aim of this study was to compare the different morphological characteristics of the hard tissue after exposure to lasers operating in the femtosecond pulse regime. Two different kinds of samples were irradiated: dentin from human extracted teeth and bovine femur samples. Different procedures were applied, while paying special care to preserving the structures. The incubation factor S was calculated to be 0.788±0.004 for the bovine femur bone. These results indicate that the incubation effect is still substantial during the femtosecond laser ablation of hard tissues. The plasma-induced ablation has reduced side effects, i.e., we observe less thermal and mechanical damage when using a superficial femtosecond laser irradiation close to the threshold conditions. In the femtosecond regime, the morphology characteristics of the cavity were strongly influenced by the change of the effective number of pulses.

  16. Factors Influencing Haptic Perception of Complex Shapes.

    PubMed

    Ehrich, Jonathan M; Flanders, Martha; Soechting, John F

    2008-01-01

    Exploration of an object by arm movement and somatosensation is a serial process that relies on memories and expectations. The present experiments tested the hypothesis that this process involves breaking the object into component shapes (primitives). This was tested by having human subjects explore shapes composed of semicircular arcs, as well as quarter circles or quarter ellipses. The subjects' perception was reported using a visual display. In the first experiment, in which a series of semicircular arcs was presented, with offsets that differed from trial to trial, performance was consistent with the perception of two (left and right) semicircles. In the second experiment, subjects often failed to detect the quarter circles or quarter ellipses and again behaved as if the object was composed of two (top and bottom) semicircles. The results suggest that the synthesis of haptically sensed shapes is biased toward simple geometric objects and that it can be strongly influenced by expectations.

  17. Early B cell factor 1 regulates adipocyte morphology and lipolysis in white adipose tissue.

    PubMed

    Gao, Hui; Mejhert, Niklas; Fretz, Jackie A; Arner, Erik; Lorente-Cebrián, Silvia; Ehrlund, Anna; Dahlman-Wright, Karin; Gong, Xiaowei; Strömblad, Staffan; Douagi, Iyadh; Laurencikiene, Jurga; Dahlman, Ingrid; Daub, Carsten O; Rydén, Mikael; Horowitz, Mark C; Arner, Peter

    2014-06-03

    White adipose tissue (WAT) morphology characterized by hypertrophy (i.e., fewer but larger adipocytes) associates with increased adipose inflammation, lipolysis, insulin resistance, and risk of diabetes. However, the causal relationships and the mechanisms controlling WAT morphology are unclear. Herein, we identified EBF1 as an adipocyte-expressed transcription factor with decreased expression/activity in WAT hypertrophy. In human adipocytes, the regulatory targets of EBF1 were enriched for genes controlling lipolysis and adipocyte morphology/differentiation, and in both humans and murine models, reduced EBF1 levels associated with increased lipolysis and adipose hypertrophy. Although EBF1 did not affect adipose inflammation, TNFα reduced EBF1 gene expression. High-fat diet intervention in Ebf1(+/-) mice resulted in more pronounced WAT hypertrophy and attenuated insulin sensitivity compared with wild-type littermate controls. We conclude that EBF1 is an important regulator of adipose morphology and fat cell lipolysis and may constitute a link between WAT inflammation, altered lipid metabolism, adipose hypertrophy, and insulin resistance.

  18. Early B-cell Factor 1 Regulates Adipocyte Morphology and Lipolysis in White Adipose Tissue

    PubMed Central

    Gao, Hui; Mejhert, Niklas; Fretz, Jackie A.; Arner, Erik; Lorente-Cebrián, Silvia; Ehrlund, Anna; Dahlman-Wright, Karin; Gong, Xiaowei; Strömblad, Staffan; Douagi, Iyadh; Laurencikiene, Jurga; Dahlman, Ingrid; Daub, Carsten O.; Rydén, Mikael; Horowitz, Mark C.; Arner, Peter

    2014-01-01

    Summary White adipose tissue (WAT) morphology characterized by hypertrophy (i.e. fewer but larger adipocytes) associates with increased adipose inflammation, lipolysis, insulin resistance and risk of diabetes. However, the causal relationships and the mechanisms controlling WAT morphology are unclear. Herein, we identified EBF1 as an adipocyte-expressed transcription factor with decreased expression/activity in WAT hypertrophy. In human adipocytes, the regulatory targets of EBF1 were enriched for genes controlling lipolysis and adipocyte morphology/differentiation and in both humans and murine models, reduced EBF1 levels associated with increased lipolysis and adipose hypertrophy. Although EBF1 did not affect adipose inflammation, TNFα reduced EBF1 gene expression. High fat diet-intervention in Ebf1+/− mice resulted in more pronounced WAT hypertrophy and attenuated insulin sensitivity compared with wild-type littermate controls. We conclude that EBF1 is an important regulator of adipose morphology and fat cell lipolysis and may constitute a link between WAT inflammation, altered lipid metabolism, adipose hypertrophy and insulin resistance. PMID:24856929

  19. RNA Polymerase Sigma Factor That Blocks Morphological Differentiation by Streptomyces coelicolor

    PubMed Central

    Gehring, Amy M.; Yoo, Narie J.; Losick, Richard

    2001-01-01

    The filamentous bacterium Streptomyces coelicolor undergoes a complicated process of morphological differentiation that begins with the formation of an aerial mycelium and culminates in sporulation. Genes required for the initiation of aerial mycelium formation have been termed bld (bald), describing the smooth, undifferentiated colonies of mutant strains. By using an insertional mutagenesis protocol that relies on in vitro transposition, we have isolated a bld mutant harboring an insertion in a previously uncharacterized gene, SCE59.12c, renamed here rsuA. The insertion mutant exhibited no measurable growth defect but failed to produce an aerial mycelium and showed a significant delay in the production of the polyketide antibiotic actinorhodin. The rsuA gene encodes an apparent anti-sigma factor and is located immediately downstream of SCE59.13c, renamed here sigU, whose product is inferred to be a member of the extracytoplasmic function subfamily of RNA polymerase sigma factors. The absence of rsuA in a strain that contained sigU caused a block in development, and the overexpression of sigU in an otherwise wild-type strain caused a delay in aerial mycelium formation. However, a strain in which both rsuA and sigU had been deleted was able to undergo morphological differentiation normally. We conclude that the rsuA-encoded anti-sigma factor is responsible for antagonizing the function of the sigma factor encoded by sigU. We also conclude that the sigU-encoded sigma factor is not normally required for development but that its uncontrolled activity obstructs morphological differentiation at an early stage. PMID:11566999

  20. Factors influencing consumer satisfaction with health care.

    PubMed

    Deshpande, Satish P; Deshpande, Samir S

    2014-01-01

    The purpose of this study was to examine factors that impact consumer satisfaction with health care. This is a secondary analysis of the Center for Studying Health System Change's 2010 Health Tracking Household Survey. Regression analysis was used to examine the impact of treatment issues, financial issues, family-related issues, sources of health care information, location, and demographics-related factors on satisfaction with health care. The study involved 12280 subjects, 56% of whom were very satisfied with their health care, whereas 66% were very satisfied with their primary care physician. Fourteen percent of the subjects had no health insurance; 34% of the subjects got their health care information from the Web. Satisfaction with primary care physician, general health status, promptness of visit to doctor, insurance type, medical cost per family, annual income, persons in family, health care information from friends, and age significantly impacted satisfaction with health care. The regression models accounted for 23% of the variance in health care satisfaction. Satisfaction with primary care physicians, health insurance, and general health status are the 3 most significant indicators of an individual's satisfaction with health care.

  1. Factors that influence current tuberculosis epidemiology.

    PubMed

    Millet, Juan-Pablo; Moreno, Antonio; Fina, Laia; del Baño, Lucía; Orcau, Angels; de Olalla, Patricia García; Caylà, Joan A

    2013-06-01

    According to WHO estimates, in 2010 there were 8.8 million new cases of tuberculosis (TB) and 1.5 million deaths. TB has been classically associated with poverty, overcrowding and malnutrition. Low income countries and deprived areas, within big cities in developed countries, present the highest TB incidences and TB mortality rates. These are the settings where immigration, important social inequalities, HIV infection and drug or alcohol abuse may coexist, all factors strongly associated with TB. In spite of the political, economical, research and community efforts, TB remains a major global health problem worldwide. Moreover, in this new century, new challenges such as multidrug-resistance extension, migration to big cities and the new treatments with anti-tumour necrosis alpha factor for inflammatory diseases have emerged and threaten the decreasing trend in the global number of TB cases in the last years. We must also be aware about the impact that smoking and diabetes pandemics may be having on the incidence of TB. The existence of a good TB Prevention and Control Program is essential to fight against TB. The coordination among clinicians, microbiologists, epidemiologists and others, and the link between surveillance, control and research should always be a priority for a TB Program. Each city and country should define their needs according to the epidemiological situation. Local TB control programs will have to adapt to any new challenge that arises in order to respond to the needs of their population.

  2. Factors influencing the intention to watch online video advertising.

    PubMed

    Lee, Joonghwa; Lee, Mira

    2011-10-01

    This study examines the factors influencing consumer intention to watch online video ads, by applying the theory of reasoned action. The attitude toward watching online video ads, the subjective norm, and prior frequency of watching online video ads positively influence the intention to watch online video ads. Further, beliefs held about entertainment and information outcomes from watching online video ads and subjective norm influence attitude toward watching these ads.

  3. Factors Influencing Agricultural Education Students' Choice to Teach

    ERIC Educational Resources Information Center

    Lawver, Rebecca Grace

    2009-01-01

    The purpose of this study was to determine the factors that influence senior level agricultural education students' choice to become secondary agriculture teachers. This study focused on the extent to which beliefs and attitude influenced students' intent to select a teaching secondary agricultural education as a career. The Agricultural…

  4. Factors Influencing Whether Children Walk to School

    PubMed Central

    Su, Jason G.; Jerrett, Michael; Mcconnell, Rob; Berhane, Kiros; Dunton, Genevieve; Shankardass, Ketan; Reynolds, Kim; Chang, Roger; Wolch, Jennifer

    2015-01-01

    Few studies have evaluated multiple levels of influence simultaneously on whether children walk to school. A large cohort of 4,338 subjects from ten communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children. PMID:23707968

  5. Factors influencing weight gain after renal transplantation.

    PubMed

    Johnson, C P; Gallagher-Lepak, S; Zhu, Y R; Porth, C; Kelber, S; Roza, A M; Adams, M B

    1993-10-01

    Weight gain following renal transplantation occurs frequently but has not been investigated quantitatively. A retrospective chart review of 115 adult renal transplant recipients was used to describe patterns of weight gain during the first 5 years after transplantation. Only 23 subjects (21%) were overweight before their transplant. Sixty-six subjects (57%) experienced a weight gain of greater than or equal to 10%, and 49 subjects (43%) were overweight according to Metropolitan relative weight criteria at 1 year after transplantation. There was an inverse correlation between advancing age and weight gain, with the youngest patients (18-29 years) having a 13.3% weight gain and the oldest patients (age greater than 50 years) having the lowest gain of 8.3% at 1 year (P = 0.047). Black recipients experienced a greater weight gain than whites during the first posttransplant year (14.6% vs. 9.0%; P = 0.043), and maintained or increased this difference over the 5-year period. Men and women experienced comparable weight gain during the first year (9.5% vs. 12.1%), but women continued to gain weight throughout the 5-year study (21.0% total weight gain). The men remained stable after the first year (10.8% total weight gain). Recipients who experienced at least a 10% weight gain also increased their serum cholesterol (mean 261 vs. 219) and triglyceride (mean 277 vs. 159) levels significantly, whereas those without weight gain did not. Weight gain did not correlate with cumulative steroid dose, donor source (living-related versus cadaver), rejection history, pre-existing obesity, the number of months on dialysis before transplantation, or posttransplant renal function. Posttransplant weight gain is related mainly to demographic factors, not to treatment factors associated with the transplant. The average weight gain during the first year after renal transplantation is approximately 10%. This increased weight, coupled with changes in lipid metabolism, may be significant in

  6. The influence of swimming demand on phenotypic plasticity and morphological integration: a comparison of two polymorphic charr species.

    PubMed

    Peres-Neto, Pedro R; Magnan, Pierre

    2004-06-01

    In northern freshwater lakes, several fish species have populations composed of discrete morphs, usually involving a divergence between benthic and limnetic morphs. Although it has been suggested that swimming demand plays an important role in morphological differentiation, thus influencing habitat selection, it is unclear how it affects reaction norms, patterns in character correlation, and levels of morphological integration. We examined whether swimming demand could induce morphological plasticity in the directions expected under divergent habitat selection, and evaluated its influence on the morphological integration in Arctic charr ( Salvelinus alpinus) and brook charr ( S. fontinalis), two congeneric species exhibiting conspicuous and subtle resource polymorphism, respectively. We found that changes in morphology were induced by differential swimming demands in both species. The length of the pectoral fin was the character that responded most strongly according to the predicted morphological expectations under divergent habitat selection. High levels of morphological plasticity, relatively low levels of integration, and differences found in the morphological correlation structure among water velocity treatments suggest that constraints on morphological change are unlikely in either species, thus allowing great potential for phenotypic flexibility in both species. The magnitude of character integration, however, was larger for Arctic charr than for brook charr. This latter result is discussed in the light of the differences in the level of polymorphism between the two species in the wild. The results of the present study indicate that swimming demand alone may not be sufficient to generate the polymorphism encountered in nature. Given that both diet and swimming demands can induce morphological changes, it would be important to conduct experiments targeting the interaction between the morphological modules related to trophic and swimming demands.

  7. Automated morphological classification of galaxies based on projection gradient nonnegative matrix factorization algorithm

    NASA Astrophysics Data System (ADS)

    Selim, I. M.; Abd El Aziz, Mohamed

    2017-02-01

    The development of automated morphological classification schemes can successfully distinguish between morphological types of galaxies and can be used for studies of the formation and subsequent evolution of galaxies in our universe. In this paper, we present a new automated machine supervised learning astronomical classification scheme based on the Nonnegative Matrix Factorization algorithm. This scheme is making distinctions between all types roughly corresponding to Hubble types such as elliptical, lenticulars, spiral, and irregular galaxies. The proposed algorithm is performed on two examples with different number of image (small dataset contains 110 image and large dataset contains 700 images). The experimental results show that galaxy images from EFIGI catalog can be classified automatically with an accuracy of ˜93% for small and ˜92% for large number. These results are in good agreement when compared with the visual classifications.

  8. Automated morphological classification of galaxies based on projection gradient nonnegative matrix factorization algorithm

    NASA Astrophysics Data System (ADS)

    Selim, I. M.; Abd El Aziz, Mohamed

    2017-04-01

    The development of automated morphological classification schemes can successfully distinguish between morphological types of galaxies and can be used for studies of the formation and subsequent evolution of galaxies in our universe. In this paper, we present a new automated machine supervised learning astronomical classification scheme based on the Nonnegative Matrix Factorization algorithm. This scheme is making distinctions between all types roughly corresponding to Hubble types such as elliptical, lenticulars, spiral, and irregular galaxies. The proposed algorithm is performed on two examples with different number of image (small dataset contains 110 image and large dataset contains 700 images). The experimental results show that galaxy images from EFIGI catalog can be classified automatically with an accuracy of ˜93% for small and ˜92% for large number. These results are in good agreement when compared with the visual classifications.

  9. The influence of tissue procurement procedures on RNA integrity, gene expression, and morphology in porcine and human liver tissue.

    PubMed

    Kap, Marcel; Sieuwerts, Anieta M; Kubista, Mikael; Oomen, Monique; Arshad, Shazia; Riegman, Peter

    2015-06-01

    The advent of molecular characterization of tissues has brought an increasing emphasis on the quality of biospecimens, starting with the tissue procurement process. RNA levels are particularly affected by factors in the collection process, but the influence of different pre-analytical factors is not well understood. Here we present the influence of tissue specimen size, as well as the transport and freezing protocols, on RNA quality. Large, medium, and smaller porcine liver samples were stored either dry, on moist gauze, or in salt solution for various times, and then frozen in either liquid nitrogen or in pre-cooled isopentane. Large and small human liver samples were frozen in pre-cooled isopentane either immediately or after one hour at room temperature. The small samples were stored dry, on moist gauze, or in salt solution. RNA was isolated and RIN values were measured. The RNA for six standard reference genes from human liver was analyzed by RT-qPCR, and tissue morphology was assessed for artifacts of freezing. Experiments using porcine liver samples showed that RNA derived from smaller samples was more degraded after one hour of cold ischemia, and that cooled transport is preferable. Human liver samples showed significant RNA degradation after 1 h of cold ischemia, which was more pronounced in smaller samples. RNA integrity was not significantly influenced by the transport or freezing method, but changes in gene expression were observed in samples either transported on gauze or in salt solution. Based on observations in liver samples, smaller samples are more subject to gene expression variability introduced by post-excision sample handling than are larger samples. Small biopsies should be transported on ice and snap frozen as soon as possible after acquisition from the patient.

  10. Corolla morphology influences diversification rates in bifid toadflaxes (Linaria sect. Versicolores)

    PubMed Central

    Fernández-Mazuecos, Mario; Blanco-Pastor, José Luis; Gómez, José M.; Vargas, Pablo

    2013-01-01

    Background and Aims The role of flower specialization in plant speciation and evolution remains controversial. In this study the evolution of flower traits restricting access to pollinators was analysed in the bifid toadflaxes (Linaria sect. Versicolores), a monophyletic group of ∼30 species and subspecies with highly specialized corollas. Methods A time-calibrated phylogeny based on both nuclear and plastid DNA sequences was obtained using a coalescent-based method, and flower morphology was characterized by means of morphometric analyses. Directional trends in flower shape evolution and trait-dependent diversification rates were jointly analysed using recently developed methods, and morphological shifts were reconstructed along the phylogeny. Pollinator surveys were conducted for a representative sample of species. Key Results A restrictive character state (narrow corolla tube) was reconstructed in the most recent common ancestor of Linaria sect. Versicolores. After its early loss in the most species-rich clade, this character state has been convergently reacquired in multiple lineages of this clade in recent times, yet it seems to have exerted a negative influence on diversification rates. Comparative analyses and pollinator surveys suggest that the narrow- and broad-tubed flowers are evolutionary optima representing divergent strategies of pollen placement on nectar-feeding insects. Conclusions The results confirm that different forms of floral specialization can lead to dissimilar evolutionary success in terms of diversification. It is additionally suggested that opposing individual-level and species-level selection pressures may have driven the evolution of pollinator-restrictive traits in bifid toadflaxes. PMID:24142920

  11. Sediment replenishment: Influence of the geometrical configuration on the morphological evolution of channel-bed

    NASA Astrophysics Data System (ADS)

    Battisacco, E.; Franca, M. J.; Schleiss, A. J.

    2016-11-01

    Dams trap sediment in the upstream reservoir, which may lead to river bed armoring, streambank erosion and failure, channel incision and reduction of the morphological diversity in the downstream river reaches. The replenishment of sediment is a mitigation measure for this problem to be applied in river reaches downstream of dams. Previously performed field experiments always used one single volume of sediment replenishment. To explore different alternatives, the replenished volume was here divided in four deposits with the motivation to influence also the morphological evolution downstream. Six different geometrical configurations together with three submergence conditions of sediment replenishment were tested for the first time in a laboratory experiment and are herein discussed. The results of the sediment replenishment mitigation technique are described in terms of occupied surface of the flume bed and the temporal evolution of erosion and transport of the introduced sediments. It is shown that, under our experimental conditions, complete submersion of the replenishment volume results in complete erosion of the placed sediment, with a high persistence of the added material along the channel length. The geometrical configuration of the replenishment volume plays a key role for the evolution of bed-forms downstream. Parallel configurations lead to a wider spread of material across the channel. Alternated configurations are suitable to produce sediment clustering and high persistence of placed material in the channel. Observed periodic mounds, considered as the initiating condition for alternate bars, follow a wavelength related to the length of the replenishment when the replenishment volumes are alternating.

  12. Alginate based hybrid copolymer hydrogels--influence of pore morphology on cell-material interaction.

    PubMed

    Gnanaprakasam Thankam, Finosh; Muthu, Jayabalan

    2014-11-04

    Alginate based hybrid copolymer hydrogels with unidirectional pore morphology were prepared to achieve synergistic biological performance for cardiac tissue engineering applications. Alginate based hybrid copolymer (ALGP) were prepared using alginate and poly(propylene fumarate) (HT-PPF) units. Different hybrid bimodal hydrogels were prepared by covalent crosslinking using poly(ethylene glycol diacrylate) and vinyl monomer viz acrylic acid, methyl methacrylate, butyl methacrylate and N-N'-methylene-bis-acrylamide and ionic crosslinking with calcium. The morphologically modified hydrogels (MM-hydrogels) with unidirectional elongated pores and high aspect ratio were prepared. MM-hydrogels favour better mechanical properties; it also enhances cell viability and infiltration due to unidirectional pores. However, the crosslinkers influence the fibroblast infiltration of these hydrogels. Synthesis of collagen and fibroblast infiltration was greater for alginate copolymer crosslinked with poly(ethylene glycol diacrylate-acrylic acid (ALGP-PA) even after one month (288%). This hybrid MM-hydrogel promoted cardiomyoblast growth on to their interstices signifying its potent applications in cardiac tissue engineering.

  13. Did Adult Diurnal Activity Influence the Evolution of Wing Morphology in Opoptera Butterflies?

    PubMed

    Penz, C M; Heine, K B

    2016-02-01

    The butterfly genus Opoptera includes eight species, three of which have diurnal habits while the others are crepuscular (the usual activity period for members of the tribe Brassolini). Although never measured in the field, it is presumed that diurnal Opoptera species potentially spend more time flying than their crepuscular relatives. If a shift to diurnal habits potentially leads to a higher level of activity and energy expenditure during flight, then selection should operate on increased aerodynamic and energetic efficiency, leading to changes in wing shape. Accordingly, we ask whether diurnal habits have influenced the evolution of wing morphology in Opoptera. Using phylogenetically independent contrasts and Wilcoxon rank sum tests, we confirmed our expectation that the wings of diurnal species have higher aspect ratios (ARs) and lower wing centroids (WCs) than crepuscular congeners. These wing shape characteristics are known to promote energy efficiency during flight. Three Opoptera wing morphotypes established a priori significantly differed in AR and WC values. The crepuscular, cloud forest dweller Opoptera staudingeri (Godman & Salvin) was exceptional in having an extended forewing tip and the highest AR and lowest WC within Opoptera, possibly to facilitate flight in a cooler environment. Our study is the first to investigate how butterfly wing morphology might evolve as a response to a behavioral shift in adult time of activity.

  14. The influence of metal Mg on micro-morphology and crystallinity of spherical hexagonal boron nitride

    SciTech Connect

    Zhang, Ning Liu, Huan; Kan, Hongmin; Wang, Xiaoyang; Long, Haibo; Zhou, Yonghui

    2015-08-15

    Highlights: • The action mechanism of Mg to the synthesis of spherical BN was explored. • The influence of Mg content on the crystallinity of h-BN powders was studied. • Even if not added any template, the spherical h-BN could be prepared. - Abstract: This search used the boric acid and borax as a source of boron, urea as a nitrogen source, Mg as metal catalyst, and thus prepared different micro-morphology and crystallinity hexagonal boron nitride powders under a flowing ammonia atmosphere at a nitriding temperature of 750 °C. The effect of Mg content on the crystallinity and micro-morphology of hexagonal boron nitride powders was studied, and the Mg action mechanism was explored. Without the added surfactant, the graphitization index (GI) was 6.87, and the diameter of the spherical h-BN was bigger. When the added Mg were 0.1 g, 0.3 g, 0.5 g and 0.7 g, the (GI) decreased to 6.04, 5.67, 4.62 and 4.84, respectively. When the Mg content was higher (0.9 g), GI value increased rapidly, and the crystallinity became bad. When the Mg content was 0.5 g, the dispersion of h-BN powders was at its optimum and refinement apparently, and the crystallinity at its highest.

  15. Influences of semiconductor morphology on the mechanical fatigue behavior of flexible organic electronics

    NASA Astrophysics Data System (ADS)

    Lee, Young-Joo; Uk Lee, Yong; Yeon, Han-Wool; Shin, Hae-A.-Seul; Evans, Louise A.; Joo, Young-Chang

    2013-12-01

    The influence of crystalline morphology on the mechanical fatigue of organic semiconductors (OSCs) was investigated using 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) as a crystalline OSC and poly(triarylamine) (PTAA) as an amorphous OSC. During cyclic bending, resistances of the OSCs were monitored using the transmission-line method on a metal-semiconductor-metal structure. The resistance of the TIPS-pentacene increased under fatigue damage in tensile-stress mode, but no such degradation was observed in the PTAA. Both OSCs were stable under compressive bending fatigue. The formation of intergranular cracks at the domain boundaries of the TIPS-pentacene was responsible for the degradation of its electrical properties under tensile bending fatigue.

  16. Influences of semiconductor morphology on the mechanical fatigue behavior of flexible organic electronics

    SciTech Connect

    Lee, Young-Joo; Yeon, Han-Wool; Shin, Hae-A-Seul; Joo, Young-Chang; Uk Lee, Yong; Evans, Louise A.

    2013-12-09

    The influence of crystalline morphology on the mechanical fatigue of organic semiconductors (OSCs) was investigated using 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) as a crystalline OSC and poly(triarylamine) (PTAA) as an amorphous OSC. During cyclic bending, resistances of the OSCs were monitored using the transmission-line method on a metal-semiconductor-metal structure. The resistance of the TIPS-pentacene increased under fatigue damage in tensile-stress mode, but no such degradation was observed in the PTAA. Both OSCs were stable under compressive bending fatigue. The formation of intergranular cracks at the domain boundaries of the TIPS-pentacene was responsible for the degradation of its electrical properties under tensile bending fatigue.

  17. Factors influencing phototaxis in nocturnal migrating birds.

    PubMed

    Zhao, Xuebing; Chen, Mingyan; Wu, Zhaolu; Wang, Zijiang

    2014-12-01

    Many migratory bird species fly during the night (nocturnal migrants) and have been shown to display some phototaxis to artificial light. During 2006 to 2009, we investigated phototaxis in nocturnal migrants at Jinshan Yakou in Xinping County (N23°56', E101°30'; 2400 m above sea-level), and at the Niaowang Mountain in Funing County (N23°30', E105°35'; 1400 m above sea-level), both in the Yunnan Province of Southwest China. A total of 5069 birds, representing 129 species, were captured by mist-netting and artificial light. The extent of phototaxis effect on bird migration was examined during all four seasons, three phases of the moon, and under two weather conditions (mist and wind). Data were statistically analyzed to determine the extent to which these factors may impact phototaxis of nocturnal migrants. The results point to phototaxis in birds migrating in the spring and autumn, especially in the autumn. Furthermore, migrating birds were more readily attracted to artificial lights during nights with little moonlight, mist, and a headwind. Regardless of the initial orientation in which birds flew, either following the wind or against the wind, birds would always fly against the wind when flying towards the light. This study broadens our understanding of the nocturnal bird migration, potentially resulting in improved bird ringing practices, increased awareness, and better policies regarding bird protection.

  18. Colorectal anastomosis: factors influencing success1

    PubMed Central

    Tagart, R E B

    1981-01-01

    Preservation of the anal sphincters is now consistent with adequate extirpation of the majority of rectal neoplasms. However, there is still a troublesome incidence of leakage through colorectal anastomoses. A number of different factors, working in combination, are responsible for this. Although most problems have been solved, and the mortality is low, the anastomotic leak rate described in the present series, and in the hands of most surgeons, remains high. Efficient suturing without tension, adequate filling and drainage of the presacral space, and antimicrobial prophylaxis effective enough to abolish abdominal wound sepsis, have been applied. The large vessel arterial blood supply to the suture line is good but the microcirculation of the left colon and rectum, upon which suture line healing ultimately depends, is suspect. Reduction of blood viscosity by deliberate lowering of the haemoglobin level before operation has been practised in the hope of improving the microcirculatory flow. The results so far are encouraging and suggest that the method is worth a continued trial. PMID:7009860

  19. Factors influencing riverine fish assemblages in Massachusetts

    USGS Publications Warehouse

    Armstrong, David S.; Richards, Todd A.; Levin, Sara B.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the Massachusetts Department of Conservation and Recreation, Massachusetts Department of Environmental Protection, and the Massachusetts Department of Fish and Game, conducted an investigation of fish assemblages in small- to medium-sized Massachusetts streams. The objective of this study was to determine relations between fish-assemblage characteristics and anthropogenic factors, including impervious cover and estimated flow alteration, relative to the effects of environmental factors, including physical-basin characteristics and land use. The results of this investigation supersede those of a preliminary analysis published in 2010. Fish data were obtained for 669 fish-sampling sites from the Massachusetts Division of Fisheries and Wildlife fish-community database. A review of the literature was used to select fish metrics - species richness, abundance of individual species, and abundances of species grouped on life history traits - responsive to flow alteration. The contributing areas to the fish-sampling sites were delineated and used with a geographic information system to determine a set of environmental and anthropogenic factors that were tested for use as explanatory variables in regression models. Reported and estimated withdrawals and return flows were used together with simulated unaltered streamflows to estimate altered streamflows and indicators of flow alteration for each fish-sampling site. Altered streamflows and indicators of flow alteration were calculated on the basis of methods developed in a previous U.S. Geological Survey study in which unaltered daily streamflows were simulated for a 44-year period (water years 1961-2004), and streamflow alterations were estimated by use of water-withdrawal and wastewater-return data previously reported to the State for the 2000-04 period and estimated domestic-well withdrawals and septic-system discharges. A variable selection process, conducted using principal

  20. Factors that Influence Students' Decision to Dropout of Online Courses

    ERIC Educational Resources Information Center

    Willging, Pedro A.; Johnson, Scott D.

    2009-01-01

    Although there are many reasons why students dropout of college courses, those reasons may be unique for students who are enrolled in an online program. Issues of isolation, disconnectedness, and technological problems may be factors that influence a student to leave a course. To understand these factors, an online survey was developed to collect…

  1. Psychosocial Factors Influencing Competency of Children's Statements on Sexual Trauma

    ERIC Educational Resources Information Center

    Kim, Tae Kyung; Choi, Soul; Shin, Yee Jin

    2011-01-01

    Objectives: The objectives of this study are to assess children's competence to state their traumatic experience and to determine psychosocial factors influencing the competency of children's statements, such as emotional factors of children and parents and trauma-related variables, in Korean child sex abuse victims. Methods: We enrolled 214…

  2. A Study of Factors Influencing Teacher Salaries in Vermont.

    ERIC Educational Resources Information Center

    Callas, Rosanne; McCormick, Rod

    A study was done of factors affecting differences in teacher salaries among Vermont towns. Data from 181 local education agencies were used for the study and a set of factors was examined that included family, community, and school information to determine what influences teacher salaries. Findings included the following: (1) average teacher's…

  3. From Hospital to Nursing Facility: Factors Influencing Decisions

    ERIC Educational Resources Information Center

    Mason, Susan E.; Auerbach, Charles; LaPorte, Heidi Heft

    2009-01-01

    This study addresses the factors influencing decisions to send medicine-surgical (med-surg) patients home or to nursing facilities (NFs). The sample (n = 7,852) was taken from a large, urban, teaching, med-surg unit where discharges were documented and data collected over a two-and-a-half-year period. Using logistical regression, the factors found…

  4. Alternative Administrative Certification: Socializing Factors Influencing Program Choice

    ERIC Educational Resources Information Center

    Bickmore, Dana L.; Bickmore, Steven T.; Raines, Sarah

    2013-01-01

    This study used an organizational socialization lens to examine factors influencing participants' decision to pursue the principalship and choice to engage in an alternate administration certification program. Through an analysis of participant focus groups and interviews, factors emerged from the codes that were compared with dimensions of…

  5. A Survey of Factors Influencing High School Start Times

    ERIC Educational Resources Information Center

    Wolfson, Amy R.; Carskadon, Mary A.

    2005-01-01

    The present study surveyed high school personnel regarding high school start times, factors influencing school start times, and decision making around school schedules. Surveys were analyzed from 345 secondary schools selected at random from the National Center for Educational Statistics database. Factors affecting reported start times included…

  6. Factors Influencing Technology Planning in Developing Countries: A Literature Review

    ERIC Educational Resources Information Center

    Keengwe, Jared; Malapile, Sandy

    2014-01-01

    This article is a literature review concerning the factors that play an important role in the development of educational technology plans in the educational system of developing countries (DCs). Largely, the technology plans are influenced by factors that emanates from within the country (internal) and those outside of their borders (external).…

  7. Professional Identity Development in Higher Education: Influencing Factors

    ERIC Educational Resources Information Center

    Barbarà-i-Molinero, Alba; Cascón-Pereira, Rosalía; Hernández-Lara, Ana beatriz

    2017-01-01

    Purpose: In the last few years, the interest on professional identity development (PID) and the factors that influence PID has become central in higher education (HE) literature. However, the knowledge developed in this domain has focussed on a factor at a time and on a degree or discipline, thus being difficult to have a general picture of all…

  8. Using mixed methods to identify factors influencing patient flow.

    PubMed

    Van Vaerenbergh, Cindy

    2009-11-01

    An effective method of identifying operational factors that influence patient flow can potentially lead to improvements and thus have huge benefits on the efficiency of hospital departments. This paper presents a new inductive mixed-method approach to identify operational factors that influence patient flow through an accident and emergency (A&E) department. Preliminary explorative observations were conducted, followed by semi-structured interviews with key stakeholders. A questionnaire survey of all medical, nursing, porter and clerical staff was then conducted. The observations provided factors for further exploration: skill-mix, long working hours, equipment availability, lack of orientation programmes, inefficient IT use and issues regarding communication structures. Interviewees highlighted several factors, including availability of medical supervision and senior nursing staff, nursing documentation issues, lack of morale due to overcrowding, personality differences and factors relating to the department layout. The questionnaire respondents strongly supported the importance of the previously identified factors. This paper demonstrates an effective mixed-method approach that can be replicated by other health-care managers to identify factors influencing patient flow. Further benefits include increased volume and quality of data, increased staff awareness for the influence of internal factors on patient flow and enhancing the evidence base for future decision making when prioritizing A&E projects.

  9. Factors Influencing Digital Reference Triage: A Think-Aloud Study

    ERIC Educational Resources Information Center

    Pomerantz, Jeffrey

    2004-01-01

    This article describes a think-aloud study conducted to identify factors that influence the decisions made by digital reference "triagers" when performing triage on questions received by digital reference services. This study follows and expands on a Delphi study that identified factors that triagers agreed on after the fact of their performance…

  10. Depression Following Hysterectomy and the Influencing Factors

    PubMed Central

    Bahri, Narjes; Tohidinik, Hamid Reza; Fathi Najafi, Tahereh; Larki, Mona; Amini, Thoraya; Askari Sartavosi, Zahra

    2016-01-01

    Background Hysterectomy is one of the most common gynecological surgeries performed worldwide. However, women undergoing this surgery often experience negative emotional reactions. Objectives This study was done with the aim of investigating the relationship between hysterectomy and postoperative depression, three months after the procedure. Materials and Methods This longitudinal study was conducted in the province of Khorasan-Razavi in Iran, using multistage sampling. At first, three cities were selected from the province by cluster sampling; then, five hospitals were randomly selected from these cities. The participants included 53 women who were hysterectomy candidates in one of the five selected hospitals. The participants’ demographics and hysterectomy procedure information were entered into two separate questionnaires, and the Beck depression inventory (BDI) was employed to measure their severity of depression before and three months after the surgery. The statistical package for the social sciences (SPSS) version 16 was used for the statistical analysis, and a P value of < 0.05 was considered to be statistically significant. Results The means and standard deviations of the participants’ depression scores before and three months after their hysterectomies were 13.01 ± 10.1 and 11.02 ± 10.3, respectively. Although the mean score of depression decreased three months after the hysterectomy, the difference was not statistically significant. However, a significant relationship was found between the satisfaction with the outcome of the hysterectomy and the postoperative depression score (P = 0.04). Conclusions In this study, undergoing a hysterectomy did not show a relationship with postoperative depression three months after the surgery. Moreover, the only factor related to depression following a hysterectomy was satisfaction with the surgery. PMID:27066267

  11. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae).

    PubMed

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E; Duan, Jian J

    2016-05-19

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions.

  12. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae)

    PubMed Central

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E.; Duan, Jian J.

    2016-01-01

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions. PMID:27194095

  13. Nurturing Sport Expertise: Factors Influencing the Development of Elite Athlete

    PubMed Central

    Baker, Joseph; Horton, Sean; Robertson-Wilson, Jennifer; Wall, Michael

    2003-01-01

    The development of expertise in sport is the result of successful interaction of biological, psychological, and sociological constraints. This review examines the training and environmental factors that influence the acquisition of sport expertise. Research examining the quality and quantity of training indicate that these two elements are crucial predictors of attainment. In addition, the possession of resources such as parental support and adequate coaching are essential. Social factors such as cultural influences and the relative age effect are also considered as determinants of sport expertise. Although it is evident that environmental factors are essential to the acquisition of high levels of sport development, further research is clearly required. PMID:24616603

  14. HemoHIM improves ovarian morphology and decreases expression of nerve growth factor in rats with steroid-induced polycystic ovaries.

    PubMed

    Kim, Sung Ho; Lee, Hae June; Kim, Joong Sun; Moon, Changjong; Kim, Jong Choon; Bae, Chun Sik; Park, Hae Ran; Jung, Uhee; Jo, Sung Kee

    2009-12-01

    Estradiol valerate (EV)-induced polycystic ovaries (PCOs) in rats cause the anovulation and cystic ovarian morphology. We investigated whether treatment with HemoHIM influences the ovarian morphology and the expression of nerve growth factor (NGF) in an EV-induced PCO rat model. PCO was induced by a single intramuscular injection of EV (4 mg, dissolved in sesame oil) in adult cycling rats. HemoHIM was either administered orally (100 mg/kg of body weight/day) for 35 consecutive days or injected intraperitoneally (50 mg/kg of body weight) every other day after EV injection. Ovarian morphology was almost normalized, and NGF was normalized in the PCO + HemoHIM group. HemoHIM lowered the high numbers of antral follicles and increased the number of corpora lutea in PCOs. The results are consistent with a beneficial effect of HemoHIM in the prevention and treatment of PCO syndrome.

  15. Metal speciation in salt marsh sediments: Influence of halophyte vegetation in salt marshes with different morphology

    NASA Astrophysics Data System (ADS)

    Pedro, Sílvia; Duarte, Bernardo; Raposo de Almeida, Pedro; Caçador, Isabel

    2015-12-01

    Salt marshes provide environmental conditions that are known to affect metal speciation in sediments. The elevational gradient along the marsh and consequent differential flooding are some of the major factors influencing halophytic species distribution and coverage due to their differential tolerance to salinity and submersion. Different species, in turn, also have distinct influences on the sediment's metal speciation, and its metal accumulation abilities. The present work aimed to evaluate how different halophyte species in two different salt marshes could influence metal partitioning in the sediment at root depth and how that could differ from bare sediments. Metal speciation in sediments around the roots (rhizosediments) of Halimione portulacoides, Sarcocornia fruticosa and Spartina maritima was determined by sequentially extracting operationally defined fractions with solutions of increasing strength and acidity. Rosário salt marsh generally showed higher concentrations of all metals in the rhizosediments. Metal partitioning was primarily related to the type of metal, with the elements' chemistry overriding the environment's influence on fractionation schemes. The most mobile elements were Cd and Zn, with greater availability being found in non-vegetated sediments. Immobilization in rhizosediments was predominantly influenced by the presence of Fe and Mn oxides, as well as organic complexes. In the more mature of both salt marshes, the differences between vegetated and non-vegetated sediments were more evident regarding S. fruticosa, while in the younger system all halophytes presented significantly different metal partitioning when compared to that of mudflats.

  16. The influence of chloride on interface kinetics and morphology of copper electrodeposits on copper single crystals

    NASA Astrophysics Data System (ADS)

    Wu, Qunwei

    The influence of chloride on the kinetics and morphology of copper electrodeposition on copper single crystal in acidified copper sulfate solution was studied by atomic force microscopy (AFM) and by electro-analytical methods. AFM was employed to image deposits on low-index single crystal copper surface formed under potential control in a fluid electrolyte. The kinetic parameters for cathodic deposition of copper on the same surface from acid sulfate and chloride solution were measured by galvanostatic polarization. Chloride has a great influence on the morphology of copper deposits Isotropic structures were obtained only in high purity sulfate solution, whereas anisotropic structures emerged when even trace amounts of chloride were present. Chloride ion stabilizes terraces oriented along preferred directions on single crystal surfaces. While deposition in pure sulfate solution is uniform and isotropic, in chloride solution it is source (or nucleation) limited. As a result, step propagation is an important mechanism of growth in chloride solution. Spiral growth in particular was observed only in chloride solution. Chloride changes the reaction mechanism of copper deposition as well. When chloride is present, the reduction of the intermediate Cu+ to Cu becomes rate limiting. Additional effects of chloride include adsorption, desorption, and CuCl precipitation on the substrate. Three regions in the polarization curve were observed. The appearance of a limiting current in the second region is due to Precipitation of a film of CuCl, which blocks deposition. Charge transfer was not the rate-controlling step in this region. At higher current densities, in the third region, the dissolution of the CuCl film follows the Tafel form in dilute chloride solution. The Tafel slopes are 40 to 120 mV/decade in the Tafel region depending on chloride and cupric ion concentration. Chloride and oxygen are competitors in the copper cathodic reduction process. Chloride ions stabilize the

  17. Factors influencing adherence among older people with osteoarthritis.

    PubMed

    Loew, Laurianne; Brosseau, Lucie; Kenny, Glen P; Durand-Bush, Natalie; Poitras, Stéphane; De Angelis, Gino; Wells, George A

    2016-09-01

    This study aims to identify potential factors that could affect adherence and influence the implementation of an evidence-based structured walking program, among older adults diagnosed with knee osteoarthritis. A total of 69 participants with mild to moderate osteoarthritis of the knee fulfilled an online survey on potential factors that could affect their adherence to an evidence-based structured walking program. Adherence with regard to the influencing factors was explored using a logistic regression model. Results tend to show higher odds of adhering to the evidence-based walking program if the participants were supervised (more than 2.9 times as high), supported by family/friends (more than 3.7 times as high), and not influenced by emotional involvement (more than 11 times as high). The odds of adhering were 3.6 times lower for participants who indicated a change in their medication intake and 3.1 times lower for individuals who considered themselves as less physically active (95 % confidence interval (CI)). Our exploratory findings identified and defined potential adherence factors that could guide health professionals in their practice to better identify positive influences and obstacles to treatment adherence, which would lead to the adoption of a more patient-centered approach. A large-scale study is required to clearly delineate the key factors that would influence adherence. We addressed a new knowledge gap by identifying the main strategies to promote the long-term adherence of community-based walking program.

  18. Critical factors and paths influencing construction workers' safety risk tolerances.

    PubMed

    Wang, Jiayuan; Zou, Patrick X W; Li, Penny P

    2016-08-01

    While workers' safety risk tolerances have been regarded as a main reason for their unsafe behaviors, little is known about why different people have different risk tolerances even when confronting the same situation. The aim of this research is to identify the critical factors and paths that influence workers' safety risk tolerance and to explore how they contribute to accident causal model from a system thinking perceptive. A number of methods were carried out to analyze the data collected through interviews and questionnaire surveys. In the first and second steps of the research, factor identification, factor ranking and factor analysis were carried out, and the results show that workers' safety risk tolerance can be influenced by four groups of factors, namely: (1) personal subjective perception; (2) work knowledge and experiences; (3) work characteristics; and (4) safety management. In the third step of the research, hypothetical influencing path model was developed and tested by using structural equation modeling (SEM). It is found that the effects of external factors (safety management and work characteristics) on risk tolerance are larger than that of internal factors (personal subjective perception and work knowledge & experiences). Specifically, safety management contributes the most to workers' safety risk tolerance through its direct effect and indirect effect; while personal subjective perception comes the second and can act as an intermedia for work characteristics. This research provides an in-depth insight of workers' unsafe behaviors by depicting the contributing factors as shown in the accident causal model developed in this research.

  19. Prenatal stress is a vulnerability factor for altered morphology and biological activity of microglia cells

    PubMed Central

    Ślusarczyk, Joanna; Trojan, Ewa; Głombik, Katarzyna; Budziszewska, Bogusława; Kubera, Marta; Lasoń, Władysław; Popiołek-Barczyk, Katarzyna; Mika, Joanna; Wędzony, Krzysztof; Basta-Kaim, Agnieszka

    2015-01-01

    Several lines of evidence suggest that the dysregulation of the immune system is an important factor in the development of depression. Microglia are the resident macrophages of the central nervous system and a key player in innate immunity of the brain. We hypothesized that prenatal stress (an animal model of depression) as a priming factor could affect microglial cells and might lead to depressive-like disturbances in adult male rat offspring. We investigated the behavioral changes (sucrose preference test, Porsolt test), the expression of C1q and CD40 mRNA and the level of microglia (Iba1 positive) in 3-month-old control and prenatally stressed male offspring rats. In addition, we characterized the morphological and biochemical parameters of potentially harmful (NO, iNOS, IL-1β, IL-18, IL-6, TNF-α, CCL2, CXCL12, CCR2, CXCR4) and beneficial (insulin-like growth factor-1 (IGF-1), brain derived neurotrophic factor (BDNF)) phenotypes in cultures of microglia obtained from the cortices of 1–2 days old control and prenatally stressed pups. The adult prenatally stressed rats showed behavioral (anhedonic- and depression-like) disturbances, enhanced expression of microglial activation markers and an increased number of Iba1-immunopositive cells in the hippocampus and frontal cortex. The morphology of glia was altered in cultures from prenatally stressed rats, as demonstrated by immunofluorescence microscopy. Moreover, in these cultures, we observed enhanced expression of CD40 and MHC II and release of pro-inflammatory cytokines, including IL-1β, IL-18, TNF-α and IL-6. Prenatal stress significantly up-regulated levels of the chemokines CCL2, CXCL12 and altered expression of their receptors, CCR2 and CXCR4 while IGF-1 production was suppressed in cultures of microglia from prenatally stressed rats. Our results suggest that prenatal stress may lead to excessive microglia activation and contribute to the behavioral changes observed in depression in adulthood. PMID

  20. Tooth anatomy risk factors influencing root canal working length accessibility

    PubMed Central

    Tang, Lu; Sun, Tuo-qi; Gao, Xiao-jie; Zhou, Xue-dong; Huang, Ding-ming

    2011-01-01

    The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth location), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P<0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure. PMID:21789962

  1. Progesterone as a morphological regulatory factor of the male and female gerbil prostate.

    PubMed

    Fochi, Ricardo A; Santos, Fernanda C A; Goes, Rejane M; Taboga, Sebastião R

    2013-12-01

    Testosterone (T) and oestrogen are the main active steroid hormones in the male and female reproductive system respectively. In female rodents progesterone (P4), together with testosterone and oestrogen, has an essential role in the regulation of the oestrous cycle, which influences the prostate physiology through their oscillations. In this work we investigated how the male and female prostate gland of Mongolian gerbils responds to surgical castration at the start of puberty and what are the effects of T, oestradiol (E2) and P4 replacement, using both quantitative and qualitative methods. We also examined the location of the main steroid receptors present in the prostate. In the castrated animals of both sexes an intense glandular regression, along with disorganization of the stromal compartment, and abundant hyperplasia was observed. The replacement of P4 secured a mild recovery of the glandular morphology, inducing the growth of secretory cells and restoring the androgen receptor (AR) cells. The administration of P4 and E2 eliminated epithelial hyperplasia and intensified gland hypertrophy, favouring the emergence of prostatic intraepithelial neoplasia (PIN). In animals treated with T and P4, even though there are some inflammatory foci and other lesions, the prostate gland revealed morphology closer to that of control animals. In summary, through the administration of P4, we could demonstrate that this hormone has anabolic characteristics, promoting hyperplasia and hypertrophy, mainly in the epithelial compartment. When combined with E2 and T, there is an accentuation of glandular hypertrophy that interrupts the development of hyperplasia and ensures the presence of a less dysplastic glandular morphology.

  2. Progesterone as a morphological regulatory factor of the male and female gerbil prostate

    PubMed Central

    Fochi, Ricardo A; Santos, Fernanda C A; Goes, Rejane M; Taboga, Sebastião R

    2013-01-01

    Testosterone (T) and oestrogen are the main active steroid hormones in the male and female reproductive system respectively. In female rodents progesterone (P4), together with testosterone and oestrogen, has an essential role in the regulation of the oestrous cycle, which influences the prostate physiology through their oscillations. In this work we investigated how the male and female prostate gland of Mongolian gerbils responds to surgical castration at the start of puberty and what are the effects of T, oestradiol (E2) and P4 replacement, using both quantitative and qualitative methods. We also examined the location of the main steroid receptors present in the prostate. In the castrated animals of both sexes an intense glandular regression, along with disorganization of the stromal compartment, and abundant hyperplasia was observed. The replacement of P4 secured a mild recovery of the glandular morphology, inducing the growth of secretory cells and restoring the androgen receptor (AR) cells. The administration of P4 and E2 eliminated epithelial hyperplasia and intensified gland hypertrophy, favouring the emergence of prostatic intraepithelial neoplasia (PIN). In animals treated with T and P4, even though there are some inflammatory foci and other lesions, the prostate gland revealed morphology closer to that of control animals. In summary, through the administration of P4, we could demonstrate that this hormone has anabolic characteristics, promoting hyperplasia and hypertrophy, mainly in the epithelial compartment. When combined with E2 and T, there is an accentuation of glandular hypertrophy that interrupts the development of hyperplasia and ensures the presence of a less dysplastic glandular morphology. PMID:24205795

  3. The Influence of Morphological Awareness on the Literacy Development of First-Grade Children

    ERIC Educational Resources Information Center

    Wolter, Julie A.; Wood, Alexis; D'zatko, Kim W.

    2009-01-01

    Purpose: The purpose of this study was twofold. First, we investigated whether first-grade children evidenced morphological awareness and whether they used their knowledge of morphological relations to guide their spelling. Second, we sought to determine whether children's morphological awareness abilities were predictive of their performance on…

  4. Influence of Morphological Awareness on College Students' Literacy Skills: A Path Analytic Approach

    ERIC Educational Resources Information Center

    Wilson-Fowler, Elizabeth B.; Apel, Kenn

    2015-01-01

    The purpose of this study was twofold: to create a measure of morphological awareness with college students and to examine effects of morphological awareness on literacy abilities. Three morphological awareness measures, and spelling, word reading, and sentence comprehension tasks were administered to 214 undergraduate college students. Item…

  5. The Influence of Variable Discharge on the Morphology of a Model Meandering River

    NASA Astrophysics Data System (ADS)

    Leverich, G. T.; Braudrick, C. A.; Sklar, L. S.; Dietrich, W.

    2006-12-01

    influencing restoration design methods that, in the past, have rarely considered the role of higher magnitude flows in shaping the channel and influencing rates of morphologic change.

  6. Influence of Space-Flight Factors on the Properties of Microorganisms, Producers of Biologically Active Substances

    NASA Astrophysics Data System (ADS)

    Krasheninnikova, T. K.; Kanaeva, E. N.; Ukraintsev, A. D.; Smolyanaya, G. L.; Kuznetsov, N. V.; Panasyuk, M. I.; Shcherbakov, G. Ya.

    2001-07-01

    The following substances were isolated under the influence of space-flight factors in cosmic experiments aboard the Mirorbital station: an MIB-90 monoisolant, which is distinguished by its morphological and biochemical properties and enhanced productivity, was isolated from the Bacillus thuringiensis ssp. Kurstaki var. Z-52culture, which is a producer of the plant protection agent Lepidocide; and MIA-74 and MIP-89 monoisolants, which are highly active toward heavy petroleum fractions (C23 C33), were isolated from the Arthrobacter OC-1culture, which is a producer of biodegradants for petroleum.

  7. A morphological survey of root grooves and their influence on periodontal attachment loss

    PubMed Central

    Bhusari, Prashant A.; Chopra, Rajan

    2011-01-01

    Periodontal health reflects a balance between harmful and protective elements in the gingival marginal area. The total plaque mass, specific periodontopathogens, the tooth morphology, and local environmental factors may challenge this balance. The periodontal ligament attachment loss shifts this balance adversely toward the periodontal disease. Objectives The aim of this retrospective study was to determine the significance of proximal root grooves as a risk factor in the periodontal attachment loss; the effect of their dimensions and locations has been evaluated. Materials and methods One hundred (100) extracted formalin stored single rooted permanent anterior teeth were studied by staining with 0.1% toludine blue to visualize attached periodontal ligament remnants. On each tooth, the loss of attachment was measured from the cemento–enamel junction to the most coronal level of the stained periodontal ligament remnants. Results The prevalence of proximal root grooves was found to be 81% and a statistically significant greater loss of attachment was present on grooved than on non-grooved surfaces (p < 0.01). Conclusions Generally, there was direct relationship between groove location, its dimensions, and maximum loss of attachment. The results suggest that proximal root grooves should be considered in periodontal diagnosis, prognosis, and treatment planning. PMID:23960505

  8. Neuronal Survival, Morphology and Outgrowth of Spiral Ganglion Neurons Using a Defined Growth Factor Combination

    PubMed Central

    Schwieger, Jana; Warnecke, Athanasia; Lenarz, Thomas; Esser, Karl-Heinz; Scheper, Verena

    2015-01-01

    Objectives The functionality of cochlear implants (CI) depends, among others, on the number and excitability of surviving spiral ganglion neurons (SGN). The spatial separation between the SGN, located in the bony axis of the inner ear, and the CI, which is inserted in the scala tympani, results in suboptimal performance of CI patients and may be decreased by attracting the SGN neurites towards the electrode contacts. Neurotrophic factors (NTFs) can support neuronal survival and neurite outgrowth. Methods Since brain-derived neurotrophic factor (BDNF) is well known for its neuroprotective effect and ciliary neurotrophic factor (CNTF) increases neurite outgrowth, we evaluated if the combination of BDNF and CNTF leads to an enhanced neuronal survival with extended neurite outgrowth. Both NTFs were added in effective high concentrations (BDNF 50ng/ml, CNTF 100ng/ml), alone and in combination, to cultured dissociated SGN of neonatal rats for 48 hours. Results The neuronal survival and neurite outgrowth were significantly higher in SGN treated with the combination of the two NTFs compared to treatment with each factor alone. Additionally, with respect to the morphology, the combination of BDNF and CNTF leads to a significantly higher number of bipolar neurons and a decreased number of neurons without neurites in culture. Conclusion The combination of BDNF and CNTF shows a great potential to increase the neuronal survival and the number of bipolar neurons in vitro and to regenerate retracted nerve fibers. PMID:26263175

  9. Quantitative characterization of the influence of the nanoscale morphology of nanostructured surfaces on bacterial adhesion and biofilm formation.

    PubMed

    Singh, Ajay Vikram; Vyas, Varun; Patil, Rajendra; Sharma, Vimal; Scopelliti, Pasquale Emanuele; Bongiorno, Gero; Podestà, Alessandro; Lenardi, Cristina; Gade, Wasudev Namdev; Milani, Paolo

    2011-01-01

    Bacterial infection of implants and prosthetic devices is one of the most common causes of implant failure. The nanostructured surface of biocompatible materials strongly influences the adhesion and proliferation of mammalian cells on solid substrates. The observation of this phenomenon has led to an increased effort to develop new strategies to prevent bacterial adhesion and biofilm formation, primarily through nanoengineering the topology of the materials used in implantable devices. While several studies have demonstrated the influence of nanoscale surface morphology on prokaryotic cell attachment, none have provided a quantitative understanding of this phenomenon. Using supersonic cluster beam deposition, we produced nanostructured titania thin films with controlled and reproducible nanoscale morphology respectively. We characterized the surface morphology; composition and wettability by means of atomic force microscopy, X-ray photoemission spectroscopy and contact angle measurements. We studied how protein adsorption is influenced by the physico-chemical surface parameters. Lastly, we characterized Escherichia coli and Staphylococcus aureus adhesion on nanostructured titania surfaces. Our results show that the increase in surface pore aspect ratio and volume, related to the increase of surface roughness, improves protein adsorption, which in turn downplays bacterial adhesion and biofilm formation. As roughness increases up to about 20 nm, bacterial adhesion and biofilm formation are enhanced; the further increase of roughness causes a significant decrease of bacterial adhesion and inhibits biofilm formation. We interpret the observed trend in bacterial adhesion as the combined effect of passivation and flattening effects induced by morphology-dependent protein adsorption. Our findings demonstrate that bacterial adhesion and biofilm formation on nanostructured titanium oxide surfaces are significantly influenced by nanoscale morphological features. The

  10. Influences on the Morphologic Response to Hurricane Sandy: Fire Island, NY (Invited)

    NASA Astrophysics Data System (ADS)

    Hapke, C. J.; Brenner, O.; Schwab, W. C.

    2013-12-01

    evolutionary history (decadal to millennial scale behavior) of the coastal system, which is controlled by the antecedent geology. Morphodynamic time series of decades to a century indicate that the central segment of the island is relatively stable, the eastern portion is experiencing shoreward retreat and the western portion is variable but generally stable. The processes driving the differential response on Fire Island are influenced by the geology/morphology of the inner shelf, which is shallowest offshore of central Fire Island and deepens to the east. Sand ridges dominate the shelf offshore of the western segment of the island and influence the distribution of wave energy reaching the coast. The pattern of differential response along the island to this extreme storm event is strikingly similar to variations documented in longer term behavior, suggesting storm response is predictable if the long-term morphodynamics and geology of a coastal system are fairly well understood.

  11. ECM proteins in a microporous scaffold influence hepatocyte morphology, function, and gene expression.

    PubMed

    Wang, Yan; Kim, Myung Hee; Shirahama, Hitomi; Lee, Jae Ho; Ng, Soon Seng; Glenn, Jeffrey S; Cho, Nam-Joon

    2016-11-29

    It is well known that a three-dimensional (3D) culture environment and the presence of extracellular matrix (ECM) proteins facilitate hepatocyte viability and maintenance of the liver-specific phenotype in vitro. However, it is not clear whether specific ECM components such as collagen or fibronectin differentially regulate such processes, especially in 3D scaffolds. In this study, a series of ECM-functionalized inverted colloidal crystal (ICC) microporous scaffolds were fabricated and their influence on Huh-7.5 cell proliferation, morphology, hepatic-specific functions, and patterns of gene expression were compared. Both collagen and fibronectin promoted albumin production and liver-specific gene expression of Huh-7.5 cells, compared with the bare ICC scaffold. Interestingly, cells in the fibronectin-functionalized scaffold exhibited different aggregation patterns to those in the collagen-functionalized scaffold, a variation that could be related to the distinct mRNA expression levels of cell adhesion-related genes. Based on these results, we can conclude that different ECM proteins, such as fibronectin and collagen, indeed play distinct roles in the phenotypic regulation of cells cultured in a 3D environment.

  12. Trabecular bone of growth plate origin influences both trabecular and cortical morphology in adulthood.

    PubMed

    Wang, Qingju; Ghasem-Zadeh, Ali; Wang, Xiao-Fang; Iuliano-Burns, Sandra; Seeman, Ego

    2011-07-01

    Skeletal fragility is common at metaphyseal regions of long bones. The cortices of this region are derived by coalescence of trabeculae around the periphery of the growth plate, not by periosteal apposition, as occurs in the diaphyses. We therefore hypothesized that trabecular bone in childhood predicted both cortical and trabecular morphology in adulthood. To test this hypothesis, we measured distal radial and tibial structure using high-resolution peripheral quantitative computed tomography in 61 daughter-mother pairs, mean age 12.5 years (range 7 to 19 years) and 44.1 years (range 32 to 50 years), respectively. The daughters' trabecular bone volume (BV/TV), thickness, number, and separation predicted the corresponding traits in their mothers. Their trabecular BV/TV also predicted their mothers' cortical thickness (r = 0.32, p = .02). By contrast, the daughters' cortical thickness did not predict their mothers' cortical thickness. The daughters had higher trabecular BV/TV than their mothers (mean ± SD, radius 0.134 ± 0.024 versus 0.124 ± 0.033, p = .03; tibia 0.145 ± 0.021 versus 0.135 ± 0.032, p < .01) owing to greater trabecular number, not thickness, and less trabecular separation. Abnormalities in the development of metaphyseal trabecular bone are likely to influence fragility in both trabecular and cortical bone of this region in adulthood.

  13. ECM proteins in a microporous scaffold influence hepatocyte morphology, function, and gene expression

    PubMed Central

    Wang, Yan; Kim, Myung Hee; Shirahama, Hitomi; Lee, Jae Ho; Ng, Soon Seng; Glenn, Jeffrey S.; Cho, Nam-Joon

    2016-01-01

    It is well known that a three-dimensional (3D) culture environment and the presence of extracellular matrix (ECM) proteins facilitate hepatocyte viability and maintenance of the liver-specific phenotype in vitro. However, it is not clear whether specific ECM components such as collagen or fibronectin differentially regulate such processes, especially in 3D scaffolds. In this study, a series of ECM-functionalized inverted colloidal crystal (ICC) microporous scaffolds were fabricated and their influence on Huh-7.5 cell proliferation, morphology, hepatic-specific functions, and patterns of gene expression were compared. Both collagen and fibronectin promoted albumin production and liver-specific gene expression of Huh-7.5 cells, compared with the bare ICC scaffold. Interestingly, cells in the fibronectin-functionalized scaffold exhibited different aggregation patterns to those in the collagen-functionalized scaffold, a variation that could be related to the distinct mRNA expression levels of cell adhesion-related genes. Based on these results, we can conclude that different ECM proteins, such as fibronectin and collagen, indeed play distinct roles in the phenotypic regulation of cells cultured in a 3D environment. PMID:27897167

  14. Influence of different crosslinking systems on the mechanical and morphological properties of thermoplastic vulcanizates

    NASA Astrophysics Data System (ADS)

    Patermann, Simone; Altstädt, Volker

    2015-05-01

    Thermoplastic vulcanizates (TPVs) combine the elastic properties of thermoset cross-linked rubbers with the melt processability of thermoplastics. The most representative examples of this class are the TPVs based on polypropylene (PP) and ethylene-propylene-diene terpolymer rubber (EPDM). The PP/EPDM blends were produced by dynamic vulcanization in a continuous extrusion process. The influence of different crosslinking systems was studied with regard to cross-link density, compression set, tensile strength/elongation at break and morphology. With increasing peroxide concentration, the cross-link density increases, leading to a reduction of the compression set by 50 %. The same improvement is only reachable with twice the concentration of phenolic resin. Only the peroxide cross-linked blends show smaller dispersed EPDM particles with increasing peroxide concentration. With a peroxide concentration between 0.2 and 0.5 wt. %, a maximum in tensile strength and elongation at break was found. For the phenolic resin cross-linked blends, the tensile strength stays almost constant with increasing phenolic resin concentration and the elongation at break shows best results at 0.5 wt. % phenolic resin. Compared to batch processes, the results show different values, but comparable trends.

  15. Influence of morphological parameters on the development of gingival recession in class III malocclusion.

    PubMed

    Warmuz, Justyna; Jagielak, Maciej; Botzenhart, Ute; Seeliger, Julia; Gedrange, Tomasz; Dominiak, Marzena

    2016-07-01

    Cephalometric analysis, including both basic cranio- and gnathometric measurements and detailed evaluation of the construction of skeletal, muscular and mucosal systems combined with estimation of the risk of recession's occurrence, can be used to determine the direction of therapy and ensure appropriate aesthetic-functional effects of treatment. The objective of the present study was to compare the influence of the chosen morphologic parameters on the development of gingival recession in the front part of the jaw in patients with Angle class III. The research material was based on the medical documentation of 1800 patients. Sixty generally healthy patients qualified for the research with prognathism. On the basis of the side-head cephalograms, measurements were carried out to describe the bone structure in the front section of the lower jaw. The lower incisor teeth set-up was also analyzed. Gum recession of the lower incisor teeth was assessed on the basis of the inside-mouth photos of the patients with class III malocclusion. The occurrence of recession in a further 4 patients resulted from such a positioning of the lower teeth. In patients in the first group, treated with complex ortho-surgical treatment, the lower incisor teeth were adjusted much more vertically in the alveola and, thus, recession occurred only in one patient. Complex orthodontic-surgical therapy contributes to recession development to a lesser degree than the sham treatment and makes it a safe alternative therapy in patients with high diathesis for occurrence or progression of an existing recession.

  16. Skull and limb morphology differentially track population history and environmental factors in the transition to agriculture in Europe.

    PubMed

    von Cramon-Taubadel, Noreen; Stock, Jay T; Pinhasi, Ron

    2013-09-22

    The Neolithic transition in Europe was a complex mosaic spatio-temporal process, involving both demic diffusion from the Near East and the cultural adoption of farming practices by indigenous hunter-gatherers. Previous analyses of Mesolithic hunter-gatherers and Early Neolithic farmers suggest that cranial shape variation preserves the population history signature of the Neolithic transition. However, the extent to which these same demographic processes are discernible in the postcranium is poorly understood. Here, for the first time, crania and postcranial elements from the same 11 prehistoric populations are analysed together in an internally consistent theoretical and methodological framework. Results show that while cranial shape reflects the population history differences between Mesolithic and Neolithic lineages, relative limb dimensions exhibit significant congruence with environmental variables such as latitude and temperature, even after controlling for geography and time. Also, overall limb size is found to be consistently larger in hunter-gatherers than farmers, suggesting a reduction in size related to factors other than thermoregulatory adaptation. Therefore, our results suggest that relative limb dimensions are not tracking the same demographic population history as the cranium, and point to the strong influence of climatic, dietary and behavioural factors in determining limb morphology, irrespective of underlying neutral demographic processes.

  17. Profiling contextual factors which influence safety in heavy vehicle industries.

    PubMed

    Edwards, Jason R D; Davey, Jeremy; Armstrong, Kerry A

    2014-12-01

    A significant proportion of worker fatalities within Australia result from truck-related incidents. Truck drivers face a number of health and safety concerns. Safety culture, viewed here as the beliefs, attitudes and values shared by an organisation's workers, which interact with their surrounding context to influence behaviour, may provide a valuable lens for exploring safety-related behaviours in heavy vehicle operations. To date no major research has examined safety culture within heavy vehicle industries. As safety culture provides a means to interpret experiences and generate behaviour, safety culture research should be conducted with an awareness of the context surrounding safety. The current research sought to examine previous health and safety research regarding heavy vehicle operations to profile contextual factors which influence health and safety. A review of 104 peer-reviewed papers was conducted. Findings of these papers were then thematically analysed. A number of behaviours and scenarios linked with crashes and non-crash injuries were identified, along with a selection of health outcomes. Contextual factors which were found to influence these outcomes were explored. These factors were found to originate from government departments, transport organisations, customers and the road and work environment. The identified factors may provide points of interaction, whereby culture may influence health and safety outcomes.

  18. Learning Strategies and Other Factors Influencing Achievement via Web Courses.

    ERIC Educational Resources Information Center

    Shih, Ching-Chun; Ingebritsen, Tom; Pleasants, John; Flickinger, Kathleen; Brown, George

    This paper reports the results of a study designed to examine how students with different learning styles functioned in World Wide Web-based courses offered by Project BIO at Iowa State University in the Fall of 1997, and to determine what factors influenced their learning. The objectives of the study were to identify: (1) the demographic…

  19. Factors Influencing Teachers' Engagement in Informal Learning Activities

    ERIC Educational Resources Information Center

    Lohman, Margaret C.

    2006-01-01

    Purpose: The purpose of this study is to examine factors influencing the engagement of public school teachers in informal learning activities. Design/methodology/approach: This study used a survey research design. Findings: Analysis of the data found that teachers rely to a greater degree on interactive than on independent informal learning…

  20. Against Conventional Wisdom: Factors Influencing Hispanic Students' Reading Achievement

    ERIC Educational Resources Information Center

    Percell, Jay C.; Kaufman, Kristina

    2013-01-01

    The researchers performed a variable analysis of the 2002 Educational Longitudinal Study data investigating factors that influence students' reading scores on standardized tests. Hispanic and non-Hispanic Scores were analyzed and controlling variables were compared to determine the effect of each on both populations. Certain variables commonly…

  1. Environmental Volunteers: Factors Influencing Their Involvement in Environmental Action

    ERIC Educational Resources Information Center

    Liarakou, Georgia; Kostelou, Eleni; Gavrilakis, Costas

    2011-01-01

    The aim of the present study was to investigate the factors that influence volunteers to become involved in environmental action. The research focused on volunteers undertaking action in summer camps organised by an environmental non-governmental organisation (NGO) in Greece. The results suggest that the environmental issues addressed in volunteer…

  2. External and Internal Factors Influencing Happiness in Elite Collegiate Athletes

    ERIC Educational Resources Information Center

    Denny, Katherine G.; Steiner, Hans

    2009-01-01

    When under conditions of high demand and allostatic load, are happiness and satisfaction in four domains (family, friends, academics, recreation) influenced more by external or internal factors? Do student-athletes who lead exceedingly complicated lives report happiness as a function of athletic achievement or internal disposition? Stanford…

  3. Factors Influencing BI Data Collection Strategies: An Empirical Investigation

    ERIC Educational Resources Information Center

    Ramakrishnan, Thiagarajan

    2010-01-01

    The purpose of this dissertation is to examine the external factors that influence an organizations' business intelligence (BI) data collection strategy when mediated by BI attributes. In this dissertation, data warehousing strategies are used as the basis on which to frame the exploration of BI data collection strategies. The attributes include…

  4. Investigating Factors that Influence Item Performance on ACS Exams

    ERIC Educational Resources Information Center

    Schroeder, Jacob; Murphy, Kristen L.; Holme, Thomas A.

    2012-01-01

    General chemistry tests from the Examinations Institute of the Division of Chemical Education of the American Chemical Society have been analyzed to identify factors that may influence how individual test items perform. In this paper, issues of item order (position within a set of items that comprise a test) and answer order (position of correct…

  5. Factors Influencing Secondary School Teachers' Adoption of Teaching Blogs

    ERIC Educational Resources Information Center

    Lai, Hui-Min; Chen, Chin-Pin

    2011-01-01

    Recently, there has been a significant proliferation in the number of teaching blogs; however, little has been explored about what motivates teachers to adopt teaching blogs. The purpose of this study is to find out which factors can significantly influence teacher decisions regarding their teaching blog adoption and the relative importance of…

  6. Computer Visualizations: Factors that Influence Spatial Anatomy Comprehension

    ERIC Educational Resources Information Center

    Nguyen, Ngan; Nelson, Andrew J.; Wilson, Timothy D.

    2012-01-01

    Computer visualizations are increasingly common in education across a range of subject disciplines, including anatomy. Despite optimism about their educational potential, students sometime have difficulty learning from these visualizations. The purpose of this study was to explore a range of factors that influence spatial anatomy comprehension…

  7. Factors Influencing Career Choice of Management Students in India

    ERIC Educational Resources Information Center

    Agarwala, Tanuja

    2008-01-01

    Purpose: This paper aims to explore the influence of a range of factors on the career choice of management students in India. The importance of different individuals in the family and at work in making career choices among these students is also to be explored. In addition, the study seeks to address the relationship of the cultural values of…

  8. Factors Influencing Medical School Faculty Disposition Toward Collective Bargaining

    ERIC Educational Resources Information Center

    Fox, Thomas G.; Blackburn, Robert T.

    1975-01-01

    Reports that faculties perceive the protection or enhancement of collegiality as the single most important factor influencing their attitudes toward unionization. Faculties see collective bargaining as a means of strengthening their position in the decisionmaking process of the medical school. (Editor/PG)

  9. Factors Influencing Females' Access to the High School Principalship

    ERIC Educational Resources Information Center

    Kruse, Rae Ann

    2012-01-01

    Scope and Method of Study: The purpose of this study was to identify the factors influencing females' access to the Oklahoma secondary school principalship. Although in the United States federal laws and policies are in place to promote equity, research indicates females are underrepresented in secondary school administration. Regardless of equity…

  10. Factors Influencing Active Learning in Small Enterprises. Working Paper.

    ERIC Educational Resources Information Center

    Hawke, Geof

    The factors influencing active learning in small enterprises were examined. Data from earlier Australian studies were examined in an attempt to provide a framework that might inform the relationship between educational systems and small enterprises. Special attention was paid to a 1988 study of systematic differences between small businesses that…

  11. What Factors Influence Vietnamese Students' Choice of University?

    ERIC Educational Resources Information Center

    Dao, Mai Thi Ngoc; Thorpe, Anthony

    2015-01-01

    Purpose: The purpose of this paper is to report the factors that influence Vietnamese students' choice of university in a little researched context where the effects of globalization and education reform are changing higher education. Design/methodology/approach: A quantitative survey was completed by 1,124 current or recently completed university…

  12. Factors that Influence Information Systems Undergraduates to Pursue IT Certification

    ERIC Educational Resources Information Center

    Hunsinger, D. Scott; Smith, Michael A.

    2008-01-01

    We identify factors that influence the intent of undergraduate information systems majors to pursue IT certification. Previous research has revealed that IT/IS hiring managers may use certification as a job requirement or to differentiate between job candidates with similar levels of education and experience. As well, salary surveys have shown…

  13. Factors Influencing Latino Participation in Community-Based Diabetes Education

    ERIC Educational Resources Information Center

    Francis, Sarah L.; Noterman, Amber; Litchfield, Ruth

    2014-01-01

    An Extension diabetes program (DP) was revised for Latinos; however, participation was limited. Factors influencing low participation rates were examined. Five Latinos interested in the DP participated in a focus group discussion. Transcripts were analyzed for themes. Preferred education programs were multi-session, local, group classes led by an…

  14. Factors Influencing Exemplary Science Teachers' Levels of Computer Use

    ERIC Educational Resources Information Center

    Hakverdi, Meral; Dana, Thomas M.; Swain, Colleen

    2011-01-01

    The purpose of this study was to examine exemplary science teachers' use of technology in science instruction, factors influencing their level of computer use, their level of knowledge/skills in using specific computer applications for science instruction, their use of computer-related applications/tools during their instruction, and their…

  15. Factors Influencing Consent to Having Videotaped Mental Health Sessions

    ERIC Educational Resources Information Center

    Ko, Kenton; Goebert, Deborah

    2011-01-01

    Objective: The authors critically reviewed the literature regarding factors influencing consent to having videotaped mental health sessions. Methods: The authors searched the literature in PubMed, PsycINFO, Google Scholar, and Web of Science from the mid-1950s through February 2009. Results: The authors identified 27 studies, of which 19 (73%)…

  16. Organizational, Financial, and Environmental Factors Influencing Deans' Tenure.

    ERIC Educational Resources Information Center

    Levin, Rebecca; Bhak, Karyn; Moy, Ernest; Valente, Ernest; Griner, Paul F.

    1998-01-01

    A study of factors influencing tenure of 382 medical school deans from 1985-1994 found that, at the schools that were less healthy financially, were under the same ownership as the primary teaching hospital, and had small faculties, deans tended to have shorter tenures and higher turnover. Possible reasons for these findings and implications for…

  17. Consumers with Major Depressive Disorder: Factors Influencing Job Placement

    ERIC Educational Resources Information Center

    Hergenrather, Kenneth C.; Haase, Eileen; Zeglin, Robert J.; Rhodes, Scott D.

    2013-01-01

    The theory of planned behavior (TPB) was applied to study the factors that influence the intention of public rehabilitation placement professionals to place consumers with major depressive disorder (MDD) in jobs. A sample of 108 public rehabilitation placement professionals in the Mid-Atlantic region of the United States completed the MDD…

  18. Factors that Influence Women's Technical Skill Development in Outdoor Adventure

    ERIC Educational Resources Information Center

    Warren, Karen; Loeffler, TA

    2006-01-01

    This article provides a theoretical foundation for understanding women's technical skill development (TSD) in outdoor adventure. An examination of societal and biological factors influencing women's TSD focuses on gender role socialization, sense of competence, technical conditioning, sexism, spatial ability, and risk-taking. The article suggests…

  19. Leadership Factors Influencing the Performance of Educational Institutions. Final Report.

    ERIC Educational Resources Information Center

    Fiedler, Fred E.

    This document is the summary report of a study having as its main objectives: (1) an intensive study of organizational and group-structural factors influencing the research and teaching effectiveness of individual faculty members and their relations to the students; (2) research investigating the effect of academic area and technology on…

  20. Factors Influencing the Development of PTSD in Battered Women.

    ERIC Educational Resources Information Center

    Cimino, Joseph J.; Dutton, Mary Ann

    In this study an interactive conceptual model was utilized in an attempt to examine variables which contribute to, and influence, the development of Post Traumatic Stress Disorder (PTSD) in battered women. This model considers the individual's response to trauma as being the product of the interaction between factors related to the characteristics…

  1. Factors Influencing Faculty Engagement--Then, Now, and Future

    ERIC Educational Resources Information Center

    Holland, Barbara A.

    2016-01-01

    In this commentary, author Barbara Holland reflects on her 1999 "Journal of Public Service & Outreach" article, "Factors and Strategies That Influence Faculty Involvement in Public Service" (EJ589785) reprinted in this 20th anniversary issue of "Journal of Higher Education Outreach and Engagement." In the late…

  2. Factors Influencing the Academic Persistence of College Students with ADHD

    ERIC Educational Resources Information Center

    Melara, Claudia Alexia

    2012-01-01

    Students with Attention Deficit Hyperactivity Disorder (ADHD) are at greater risk for failing to complete their postsecondary educational degrees than their typical peers. The present qualitative sought to identify factors influencing the academic persistence of students with ADHD in postsecondary settings. Utilizing direct interviews with…

  3. Social and Environmental Factors Influencing In-Prison Drug Use

    ERIC Educational Resources Information Center

    Woodall, James

    2012-01-01

    Purpose: There is a strong political imperative to regard the prison as a key social setting for health promotion, but evidence indicates that drug misuse continues to be a significant issue for many prisoners. This paper aims to examine the social and environmental factors within the setting that influence individuals' drug taking.…

  4. Factors Influencing Student Choice of College and Course of Study

    ERIC Educational Resources Information Center

    Snelling, W. Rodman; Boruch, Robert

    1970-01-01

    Relates results of a longitudinal study (1958-67) of 16,395 science majors, revealing what grade level (prior to 9th grade through college-6th year) science was chosen as their major interest, when final major was selected, and when highest degree aspiration was decided. Presents discussion of factors influencing students' choice of liberal arts…

  5. Factors That Influence Faculty Adoption of Learning-Centered Approaches

    ERIC Educational Resources Information Center

    Blumberg, Phyllis

    2016-01-01

    This article proposes a recommended course of action for faculty development based upon Rogers' theory of Diffusion of Innovations and data collected in a study looking at the prevalence of use of learning-centered teaching practices. Specific faculty development strategies are aligned with Rogers' factors influencing decisions to adopt…

  6. Factors that Influence Children's Responses to Peer Victimization

    ERIC Educational Resources Information Center

    Terranova, Andrew M.

    2009-01-01

    Children's responses to peer victimization are associated with whether the victimization continues, and its impact on adjustment. Yet little longitudinal research has examined the factors influencing children's responses to peer victimization. In a sample of 140 late elementary school children (n = 140, Mean age = 10 years, 2 months, 55% female,…

  7. An Investigation of Classroom Factors That Influence Proof Construction Ability.

    ERIC Educational Resources Information Center

    McCrone, Sharon Soucy; Martin, Tami S.; Dindyal, Jaguthsing; Wallace, Michelle L.

    This paper on classroom factors influencing students' proof construction ability reports findings from the data collected in the first two years of a three-year National Science Foundation (NSF)-funded project. Four different classrooms, two from each participating school, were involved in the project. Data sources included videotaped classroom…

  8. Factors Influencing Role Behaviors by Professional Exemplars in Hospitals

    ERIC Educational Resources Information Center

    Bolding, Deborah J.

    2013-01-01

    This basic qualitative study explored factors that influenced the development of professional role behaviors of nurses, occupational and physical therapists who were characterized as exemplars in the acute hospital setting. The participants, four occupational therapists, four nurses, and four physical therapists were interviewed using a…

  9. Factors Influencing the Institutionalization of Distance Education in Higher Education

    ERIC Educational Resources Information Center

    Pina, Anthony A.

    2008-01-01

    The purpose of this study was to determine actions that colleges and universities can take to institutionalize their distance education programs. Thirty factors found to influence the institutionalization of innovations were identified from the literature. These were rated by distance education faculty and leaders as to their importance for…

  10. Factors That Influence the Attrition of Mentors in Rural Areas

    ERIC Educational Resources Information Center

    Givens, Sharon Leenese

    2012-01-01

    This research is a qualitative case study exploring the factors that influence the attrition of mentors in rural areas. Mentoring initiatives and programs have proliferated throughout schools in an effort to provide students with positive role models, increase graduation rates and improve overall performance Mentoring programs are an increasingly…

  11. Abuse of Working Children and Influencing Factors, Turkey

    ERIC Educational Resources Information Center

    Oncu, Emine; Kurt, Ahmet Oner; Esenay, Figen Isik; Ozer, Fatma

    2013-01-01

    Objective: The study was planned as the research of the kind/kinds of abuse and the factors influencing the abuse that the children under 18 who are working full-time at a workplace and enrolled in a vocational training center subjected to. Method: Questionnaires were administered to 595 apprentices who were attending a vocational training center.…

  12. Factors Influencing School Choice in a School District in Delaware

    ERIC Educational Resources Information Center

    Kennedy, John J., Jr.

    2012-01-01

    The purpose of this descriptive study is to examine the factors that influenced parents in a school district in Delaware when they selected a high school for their child. This study also sought to examine the sources of information that parents used. Also examined was the impact of socio-economic status in the high school selection process. A…

  13. Adolescents Who Drive Under the Influence: Correlates and Risk Factors.

    ERIC Educational Resources Information Center

    Mayton, Daniel M., II; And Others

    This study was designed to determine the correlates or potential risk factors which predict whether an adolescent who drinks or uses drugs will refrain from driving under the influence, or will drive in this condition. A group of 426 rural high school seniors completed a questionnaire which assessed drug use patterns and previously identified risk…

  14. Factors Influencing Practical Training Quality in Iranian Agricultural Higher Education

    ERIC Educational Resources Information Center

    Mojarradi, Gholamreza; Karamidehkordi, Esmail

    2016-01-01

    This paper presents an analysis of the factors influencing the practical training quality of agricultural higher education programmes from the senior students' perspective. The study was conducted in two public universities located in the north-west of Iran using a cross-sectional survey and structured interviews with a randomised sample of 254…

  15. Factors Influencing Stress, Burnout, and Retention of Secondary Teachers

    ERIC Educational Resources Information Center

    Fisher, Molly H.

    2011-01-01

    This study examines the stress, burnout, satisfaction, and preventive coping skills of nearly 400 secondary teachers to determine variables contributing to these major factors influencing teachers. Analysis of Variance (ANOVA) statistics were conducted that found the burnout levels between new and experienced teachers are significantly different,…

  16. Factors Influencing Student Participation in College Study Abroad Programs

    ERIC Educational Resources Information Center

    Bandyopadhyay, Soumava; Bandyopadhyay, Kakoli

    2015-01-01

    This paper proposes a theoretical framework to investigate the factors that influence student participation in college study abroad programs. The authors posit that students' general perceptions regarding the study abroad experience and their expectations of intercultural awareness from study abroad programs will impact their perceptions of…

  17. Factors Influencing Undergraduates' Self-Evaluation of Numerical Competence

    ERIC Educational Resources Information Center

    Tariq, Vicki N.; Durrani, Naureen

    2012-01-01

    This empirical study explores factors influencing undergraduates' self-evaluation of their numerical competence, using data from an online survey completed by 566 undergraduates from a diversity of academic disciplines, across all four faculties at a post-1992 UK university. Analysis of the data, which included correlation and multiple regression…

  18. Factors Influencing Residents' Satisfaction in Residential Aged Care

    ERIC Educational Resources Information Center

    Chou, Shu-Chiung; Boldy, Duncan P.; Lee, Andy H.

    2003-01-01

    Purpose: The aim of this study was to identify the important factors influencing residents' satisfaction in residential aged care and to provide a better understanding of their interrelationships. Design and Methods: A cross-sectional survey design was used to collect the required information, including resident satisfaction, resident dependency…

  19. Multilevel Factors Influencing Maternal Stress during the First Three Years.

    ERIC Educational Resources Information Center

    Mulsow, Miriam; Caldera, Yvonne M.; Pursley, Marta; Reifman, Alan; Huston, Aletha C.

    2002-01-01

    Study applies family stress theory to the influence of personal, child, and familial factors on a mother's parenting stress during the first 3 years of her infant's life. Mother's personality was most predictive of parenting stress. Counterintuitively, mothers who were more satisfied with work or school choices were more likely to be chronically…

  20. Pantomime Production by People with Aphasia: What Are Influencing Factors?

    ERIC Educational Resources Information Center

    van Nispen, Karin; van de Sandt-Koenderman, Mieke; Mol, Lisette; Krahmer, Emiel

    2016-01-01

    Purpose: The present article aimed to inform clinical practice on whether people with aphasia (PWA) deploy pantomime techniques similarly to participants without brain damage (PWBD) and if not, what factors influence these differences. Method: We compared 38 PWA to 20 PWBD in their use of 6 representation techniques ("handling,"…

  1. A review of major factors influencing plant responses to recreation impacts

    NASA Astrophysics Data System (ADS)

    Kuss, Fred R.

    1986-09-01

    This article reviews some of the more important factors found to influence the susceptibility of plants to trampling impacts associated with recreational use of natural areas. A three-way interaction mediates plant responses to impacts: plant x environment x stress level(s). Plant responses vary in part according to the genetic constitution of the plant, life and growth form, the adaptive flexibility of the plant, and anatomical differences inherent to growth habit and morphology. Other factors that influence plant sensitivities to impacts are the habitat environments in which plants grow, since a number of conditions such as moisture excesses or deficiencies, nitrogen or oxygen starvation, late frosts, etc., cause physiological injury and may increase plant sensitivity to impacts. Among the environmental factors that may increase or lessen plant sensitivities to impacts are soil moisture levels, canopy density, elevation, aspect, microclimate, soil drainage, texture, fertility and productivity. Seasonal influences also bear consideration since environmental changes and phonological and physiological events are mediated by time of year. Stresses are caused by both direct and indirect forms of impact and vary according to season of use, frequency and amount of use, and the type of activity. These interactions are further complicated by evidence that inter- and intraspecific competition, antagonism, and commensalism may influence differences in the sensitivity of plant communities to impacts.

  2. Factors influencing the flavour of game meat: A review.

    PubMed

    Neethling, J; Hoffman, L C; Muller, M

    2016-03-01

    Flavour is a very important attribute contributing to the sensory quality of meat and meat products. Although the sensory quality of meat includes orthonasal and retronasal aroma, taste, as well as appearance, juiciness and other textural attributes, the focus of this review is primarily on flavour. The influence of species, age, gender, muscle anatomical location, diet, harvesting conditions, ageing of meat, packaging and storage, as well as cooking method on the flavour of game meat are discussed. Very little research is available on the factors influencing the flavour of the meat derived from wild and free-living game species. The aim of this literature review is thus to discuss the key ante- and post-mortem factors that influence the flavour of game meat, with specific focus on wild and free-living South African game species.

  3. Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

    PubMed Central

    Runge, Fabian; Ndambi, Beninweck; Thines, Marco

    2012-01-01

    Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and

  4. Factors influencing first childbearing timing decisions among men: Path analysis

    PubMed Central

    Kariman, Nourossadat; Amerian, Maliheh; Jannati, Padideh; Salmani, Fatemeh

    2016-01-01

    Background: Factors that influence men’s childbearing intentions have been relatively unexplored in the literature. Objective: This study aimed to determine the influencing factors about the first childbearing timing decisions of men. Materials and Methods: In this cross-sectional study, 300 men who were referred to private and governmental healthcare centers in Shahrood, Iran were randomly recruited from April to September 2014. Data were collected using a demographic questionnaire, the Quality of Life Questionnaire; ENRICH Marital Satisfaction Questionnaire, Synder’s Hope Scale, and the Multidimensional Scale of Perceived Social Support. Results: After removing the statistically insignificant paths, men’s age at marriage had the highest direct effect (β=0.86) on their first childbearing decision. Marital satisfaction (β=-0.09), social support (β=0.06), economic status (β=0.06), and quality of life (β=-0.08) were other effective factors on men’s first childbearing decisions. Moreover, marital satisfaction and social support had significant indirect effects on men’s childbearing decisions (β=-0.04 and -0.01, respectively). Conclusion: Many factors, including personal factors (age at marriage and quality of life), family factors (marital satisfaction), and social factors (social support), can affect men’s decision to have a child. Policymakers are hence required to develop strategies to promote the socioeconomic and family conditions of the couples and to encourage them to have as many children as they desire at an appropriate time. PMID:27738661

  5. Factors influencing trust and mistrust in health promotion partnerships.

    PubMed

    Jones, Jacky; Barry, Margaret M

    2016-07-27

    Partnerships between sectors can achieve better outcomes than can be achieved by individual partners working alone. Trust is necessary for partnerships to function effectively. Mistrust makes partnership working difficult, if not impossible. There has been little research into partnership functioning factors that influence trust and mistrust. This study aimed to identify these factors in health promotion partnerships. Data were collected from 337 partners in 40 health promotion partnerships using a postal survey. The questionnaire incorporated multi-dimensional scales designed to assess the contribution of factors that influence partnership trust and mistrust. Newly validated scales were developed for trust, mistrust and power. Multiple regression analysis was used to identify the significance of each factor to partnership trust and mistrust. Power was found to be the only predictor of partnership trust. Power, leadership, and efficiency were the most important factors influencing partnership mistrust. Power in partnerships must be shared or partners will not trust each other. Power-sharing and trust-building mechanisms need to be built into partnerships from the beginning and sustained throughout the collaborative process.

  6. A Review of Factors Influencing Athletes' Food Choices.

    PubMed

    Birkenhead, Karen L; Slater, Gary

    2015-11-01

    Athletes make food choices on a daily basis that can affect both health and performance. A well planned nutrition strategy that includes the careful timing and selection of appropriate foods and fluids helps to maximize training adaptations and, thus, should be an integral part of the athlete's training programme. Factors that motivate food selection include taste, convenience, nutrition knowledge and beliefs. Food choice is also influenced by physiological, social, psychological and economic factors and varies both within and between individuals and populations. This review highlights the multidimensional nature of food choice and the depth of previous research investigating eating behaviours. Despite numerous studies with general populations, little exploration has been carried out with athletes, yet the energy demands of sport typically require individuals to make more frequent and/or appropriate food choices. While factors that are important to general populations also apply to athletes, it seems likely, given the competitive demands of sport, that performance would be an important factor influencing food choice. It is unclear if athletes place the same degree of importance on these factors or how food choice is influenced by involvement in sport. There is a clear need for further research exploring the food choice motives of athletes, preferably in conjunction with research investigating dietary intake to establish if intent translates into practice.

  7. Variance of indoor radon concentration: Major influencing factors.

    PubMed

    Yarmoshenko, I; Vasilyev, A; Malinovsky, G; Bossew, P; Žunić, Z S; Onischenko, A; Zhukovsky, M

    2016-01-15

    Variance of radon concentration in dwelling atmosphere is analysed with regard to geogenic and anthropogenic influencing factors. Analysis includes review of 81 national and regional indoor radon surveys with varying sampling pattern, sample size and duration of measurements and detailed consideration of two regional surveys (Sverdlovsk oblast, Russia and Niška Banja, Serbia). The analysis of the geometric standard deviation revealed that main factors influencing the dispersion of indoor radon concentration over the territory are as follows: area of territory, sample size, characteristics of measurements technique, the radon geogenic potential, building construction characteristics and living habits. As shown for Sverdlovsk oblast and Niška Banja town the dispersion as quantified by GSD is reduced by restricting to certain levels of control factors. Application of the developed approach to characterization of the world population radon exposure is discussed.

  8. Consumer's Online Shopping Influence Factors and Decision-Making Model

    NASA Astrophysics Data System (ADS)

    Yan, Xiangbin; Dai, Shiliang

    Previous research on online consumer behavior has mostly been confined to the perceived risk which is used to explain those barriers for purchasing online. However, perceived benefit is another important factor which influences consumers’ decision when shopping online. As a result, an integrated consumer online shopping decision-making model is developed which contains three elements—Consumer, Product, and Web Site. This model proposed relative factors which influence the consumers’ intention during the online shopping progress, and divided them into two different dimensions—mentally level and material level. We tested those factors with surveys, from both online volunteers and offline paper surveys with more than 200 samples. With the help of SEM, the experimental results show that the proposed model and method can be used to analyze consumer’s online shopping decision-making process effectively.

  9. Surface EMG of the masticatory muscles (part 2): fatigue testing, mastication analysis and influence of different factors.

    PubMed

    Hugger, S; Schindler, H J; Kordass, B; Hugger, A

    2013-01-01

    The second part of this review of the literature on the clinical significance of surface electromyography (EMG) of the masticatory muscles systematically examines the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, investigating relevant aspects of EMG activity during prolonged chewing activity (fatigue effects), during the mastication process, and under the influence of different factors. Studies on the influence of factors such as gender, age, tooth status, orofacial morphology and (acute) pain, the significance of different occlusal relationships during static and dynamic occlusion, and the impact of changes in static occlusion on EMG activity of the masticatory muscles were included in the review.

  10. The influence of the San Gregorio fault on the morphology of Monterey Canyon

    USGS Publications Warehouse

    McHugh, C.M.G.; Ryan, William B. F.; Eittreim, S.; Donald, Reed

    1998-01-01

    A side-scan sonar survey was conducted of Monterey Canyon and the San Gregorio fault zone, off shore of Monterey Bay. The acoustic character and morphology of the sonar images, enhanced by SeaBeam bathymetry, show the path of the San Gregorio fault zone across the shelf, upper slope, and Monterey Canyon. High backscatter linear features a few kilometers long and 100 to 200 m wide delineate the sea-floor expression of the fault zone on the shelf. Previous studies have shown that brachiopod pavements and carbonate crusts are the source of the lineations backscatter. In Monterey Canyon, the fault zone occurs where the path of the canyon makes a sharp bend from WNW to SSW (1800 m). Here, the fault is marked by NW-SE-trending, high reflectivity lineations that cross the canyon floor between 1850 m and 1900 m. The lineations can be traced to ridges on the northwestern canyon wall where they have ~ 15 m of relief. Above the low-relief ridges, bowl-shaped features have been excavated on the canyon wall contributing to the widening of the canyon. We suggest that shear along the San Gregorio fault has led to the formation of the low-relief ridges near the canyon wall and that carbonate crusts, as along the shelf, may be the source of the high backscatter features on the canyon floor. The path of the fault zone across the upper slope is marked by elongated tributary canyons with high backscatter floors and 'U'-shaped cross-sectional profiles. Linear features and stepped scarps suggestive of recent crustal movement and mass-wasting, occur on the walls and floors of these canyons. Three magnitude-4 earthquakes have occurred within the last 30 years in the vicinity of the canyons that may have contributed to the observed features. As shown by others, motion along the fault zone has juxtaposed diverse lithologies that outcrop on the canyon walls. Gully morphology and the canyon's drainage patterns have been influenced by the substrate into which the gullies have formed.

  11. Variation in Salamander Tail Regeneration Is Associated with Genetic Factors That Determine Tail Morphology

    PubMed Central

    Voss, Gareth J.; Kump, D. Kevin; Walker, John A.; Voss, S. Randal

    2013-01-01

    Very little is known about the factors that cause variation in regenerative potential within and between species. Here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. A hybrid ambystomatid salamander (Ambystoma mexicanum x A. andersoni) was crossed to an A. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. Following metamorphosis, each salamander’s tail tip was amputated and allowed to regenerate, and then amputated a second time and allowed to regenerate. Also, DNA was isolated from all individuals and genotypes were determined for 187 molecular markers distributed throughout the genome. The area of tissue that regenerated after the first and second amputations was highly positively correlated across males and females. Males presented wider tails and regenerated more tail tissue during both episodes of regeneration. Approximately 66–68% of the variation in regenerative outgrowth was explained by tail width, while tail length and genetic sex did not explain a significant amount of variation. A small effect QTL was identified as having a sex-independent effect on tail regeneration, but this QTL was only identified for the first episode of regeneration. Several molecular markers significantly affected regenerative outgrowth during both episodes of regeneration, but the effect sizes were small (<4%) and correlated with tail width. The results show that ambysex and minor effect QTL explain variation in adult tail morphology and importantly, tail width. In turn, tail width at the amputation plane largely determines the rate of regenerative outgrowth. Because amputations in this study were made at approximately the same position of the tail, our results resolve an outstanding question in regenerative biology: regenerative outgrowth positively co-varies as a function of tail width at the amputation site. PMID:23843997

  12. Mitochondrial outer membrane proteome of Trypanosoma brucei reveals novel factors required to maintain mitochondrial morphology.

    PubMed

    Niemann, Moritz; Wiese, Sebastian; Mani, Jan; Chanfon, Astrid; Jackson, Christopher; Meisinger, Chris; Warscheid, Bettina; Schneider, André

    2013-02-01

    Trypanosoma brucei is a unicellular parasite that causes devastating diseases in humans and animals. It diverged from most other eukaryotes very early in evolution and, as a consequence, has an unusual mitochondrial biology. Moreover, mitochondrial functions and morphology are highly regulated throughout the life cycle of the parasite. The outer mitochondrial membrane defines the boundary of the organelle. Its properties are therefore key for understanding how the cytosol and mitochondria communicate and how the organelle is integrated into the metabolism of the whole cell. We have purified the mitochondrial outer membrane of T. brucei and characterized its proteome using label-free quantitative mass spectrometry for protein abundance profiling in combination with statistical analysis. Our results show that the trypanosomal outer membrane proteome consists of 82 proteins, two-thirds of which have never been associated with mitochondria before. 40 proteins share homology with proteins of known functions. The function of 42 proteins, 33 of which are specific to trypanosomatids, remains unknown. 11 proteins are essential for the disease-causing bloodstream form of T. brucei and therefore may be exploited as novel drug targets. A comparison with the outer membrane proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. Known factors involved in the regulation of mitochondrial morphology are virtually absent in T. brucei. Interestingly, RNAi-mediated ablation of three outer membrane proteins of unknown function resulted in a collapse of the network-like mitochondrion of procyclic cells and for the first time identified factors that control mitochondrial shape in T. brucei.

  13. Variation in salamander tail regeneration is associated with genetic factors that determine tail morphology.

    PubMed

    Voss, Gareth J; Kump, D Kevin; Walker, John A; Voss, S Randal

    2013-01-01

    Very little is known about the factors that cause variation in regenerative potential within and between species. Here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. A hybrid ambystomatid salamander (Ambystoma mexicanum x A. andersoni) was crossed to an A. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. Following metamorphosis, each salamander's tail tip was amputated and allowed to regenerate, and then amputated a second time and allowed to regenerate. Also, DNA was isolated from all individuals and genotypes were determined for 187 molecular markers distributed throughout the genome. The area of tissue that regenerated after the first and second amputations was highly positively correlated across males and females. Males presented wider tails and regenerated more tail tissue during both episodes of regeneration. Approximately 66-68% of the variation in regenerative outgrowth was explained by tail width, while tail length and genetic sex did not explain a significant amount of variation. A small effect QTL was identified as having a sex-independent effect on tail regeneration, but this QTL was only identified for the first episode of regeneration. Several molecular markers significantly affected regenerative outgrowth during both episodes of regeneration, but the effect sizes were small (<4%) and correlated with tail width. The results show that ambysex and minor effect QTL explain variation in adult tail morphology and importantly, tail width. In turn, tail width at the amputation plane largely determines the rate of regenerative outgrowth. Because amputations in this study were made at approximately the same position of the tail, our results resolve an outstanding question in regenerative biology: regenerative outgrowth positively co-varies as a function of tail width at the amputation site.

  14. Factors Influencing Neurodevelopment after Cardiac Surgery during Infancy

    PubMed Central

    Hövels-Gürich, Hedwig Hubertine

    2016-01-01

    Short- and long-term neurodevelopmental (ND) disabilities with negative impact on psychosocial and academic performance, quality of life, and independence in adulthood are known to be the most common sequelae for surviving children after surgery for congenital heart disease (CHD). This article reviews influences and risk factors for ND impairment. For a long time, the search for independent risk factors was focused on the perioperative period and modalities of cardiopulmonary bypass (CPB). CPB operations to ensure intraoperative vital organ perfusion and oxygen supply with or without circulatory arrest or regional cerebral perfusion bear specific risks. Examples of such risks are embolization, deep hypothermia, flow rate, hemodilution, blood gas management, postoperative hyperthermia, systemic inflammatory response, and capillary leak syndrome. However, influences of these procedure-specific risk factors on ND outcome have not been found as strong as expected. Furthermore, modifications have not been found to support the effectiveness of the currently used neuroprotective strategies. Postoperative factors, such as need for extracorporal membrane oxygenation or assist device support and duration of hospital stay, significantly influence ND parameters. On the other hand, the so-called “innate,” less modifiable patient-specific risk factors have been found to exert significant influences on ND outcomes. Examples are type and severity of CHD, genetic or syndromic abnormalities, as well as prematurity and low birth weight. Structural and hemodynamic characteristics of different CHDs are assumed to result in impaired brain growth and delayed maturation with respect to the white matter. Beginning in the fetal period, this so-called “encephalopathy of CHD” is suggested a major innate risk factor for pre-, peri-, and postoperative additional hypoxic or ischemic brain injury and subsequent ND impairment. Furthermore, MRI studies on brain volume, structure, and

  15. Factors influencing validation of ambulatory blood pressure measuring devices.

    PubMed

    O'Brien, E; Atkins, N; Staessen, J

    1995-11-01

    With the introduction of 24 h ambulatory blood pressure monitoring into clinical practice a vast market for ambulatory blood pressure monitoring devices has been created. To satisfy this market manufacturers are producing an array of ambulatory blood pressure monitoring devices. There is no obligation on manufacturers to have such devices validated independently, even though two national protocols, one from the British Hypertension Society (BHS) and the other from the Association for the Advancement of Medical Instrumentation (AAMI), call for independent validation and state the means of doing so. However, many factors can influence the validation procedure. They include compliance to the protocol being employed; the accuracy of the standard; establishing precisely the model being validated; the influences of blood pressure level, age and exercise on device accuracy; the provisions necessary for special populations, such as pregnant women, the elderly and children; the influence of oscillometric versus Korotkoff sound detection and electrocardiographic gating on comparative measurements; the assessment of performance as distinct from accuracy; and the relevance of general factors, such as the algorithm being employed and computer compatibility. Forty-three ambulatory blood pressure monitoring devices have been marketed for ambulatory blood pressure measurement and of those only 18 have been validated according to either the BHS or the AAMI protocol. The influence of the factors listed above on the validation studies of those devices will be considered and the relevance of validation procedures to the clinical use of ambulatory blood pressure monitoring devices will be discussed.

  16. Influencing Factors on Life-Cycle Cost of Mooring Facilities

    NASA Astrophysics Data System (ADS)

    Sato, Wataru; Yokota, Hiroshi; Hashimoto, Katsufumi; Furuya, Koichi; Kato, Hirotoshi

    It is required that infrastructure should satisfy performance requirement through their service life based on an appropriate life cycle management strategy. Now adays, to determine the maintenance strategy and to consider the appropriate timing and method of intervention, the life-cycle cost (LCC) has been widely used as one of the decision-making indices. However, many factors influence on the estimation of LCC and they have not been adequately investigated. In this paper, the authors have made analytical investigation to quantify the influence of important factors on the results of LCC estimation. Four kinds of mooring facilities are focused; two of them are open-type wharves and the other two are sheet pile type quay walls having different design water depths. Prediction of deterioration progress and performance degradation is made by using the Markov models. The influences of structural sizes, transition probability in the Markov model, design service life, periodic inspection and methods of intervention on LCC were investigated. The influence of those factors has been discussed based on the calculated results of LCC by creating the maintenance scenarios for model mooring facilities.

  17. Influence of social factors on lead exposure and child development.

    PubMed Central

    Bornschein, R L

    1985-01-01

    A brief overview of current views of child development is provided, with particular attention given to the role the child's physical and social environment plays in influencing the developmental process. Examples from the recent literature are used to illustrate how these factors can influence lead exposure and most importantly how they might interact with lead to ameliorate or exacerbate possible lead effects. An example is provided which demonstrates that failure to control adequately and to adjust the data statistically to correct for the influence of these factors can lead one erroneously to attribute cognitive and behavioral changes to lead. Finally, data from the Cincinnati Prospective Lead Study are presented to illustrate the application of structural equation modeling as a means for unraveling the complex web of sociodemographic, environmental and behavioral influences on childhood lead exposure. The latter analysis indicates that for children less than 24 months of age, lead-containing dust in the home and on the children's hands are important determinates of their blood lead levels. This relationship is influenced by the amount of maternal involvement with their child and other indices of interaction between the child and primary caregiver. PMID:2417831

  18. Genetic and nongenetic factors influencing substance use by adolescents.

    PubMed

    Liepman, Michael R; Calles, Joseph L; Kizilbash, Leena; Nazeer, Ahsan; Sheikh, Suhail

    2002-06-01

    Substance use by adolescents can lead to mortality, physical and social morbidity, and a brain disorder called substance dependence if allowed to progress to chronic, repetitive self-administration. Substance abuse and dependence can begin in adolescence or adulthood, but many of the attitudes and behaviors that affect risk become established during adolescence. Genetic risk factors have been identified for at least two distinct disorders and more are under active study to determine the cause and pathophysiology of addictive disorders. Although much remains to be done, a complex interplay of numerous genetic and environmental risk factors clearly is involved. An understanding of the most important environmental risk factors has led to effective primary prevention approaches; knowledge of the genetic risk factors and neuropharmacology of drugs of abuse in the brain is beginning to influence secondary prevention efforts and treatment, including better medications for addictive disorders. A large proportion of adolescents carry a genetic vulnerability that can be expressed when they accept peer and societal influences that promote experimentation with substances of abuse. At that point, the genetic factors take over, maintaining the drug self-administration pattern. Decay of social status results from association with drug-using peers and shifts in priorities supportive of drug use rather than education and productivity. More research into the genetic risk factors and applications of current knowledge to treatment is needed.

  19. FACTORS INFLUENCING THE DESIGN OF BIOACCUMULATION FACTOR AND BIOTA-SEDIMENT ACCUMULATION FACTOR FIELD STUDIES

    EPA Science Inventory

    General guidance for designing field studies to measure bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) is not available. To develop such guidance, a series of modeling simulations were performed to evaluate the underlying factors and principles th...

  20. FACTORS INFLUENCING THE DESIGN OF BIOACCUMULATION FACTOR AND BIOTA-SEDIMENT ACCUMULATION FACTOR FIELD STUDIES

    EPA Science Inventory

    A series of modeling simulations were performed to develop an understanding of the underlying factors and principles involved in developing field sampling designs for measuring bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs. These simulations reveal...

  1. Factors influencing societal response of nanotechnology: an expert stakeholder analysis

    NASA Astrophysics Data System (ADS)

    Gupta, Nidhi; Fischer, Arnout R. H.; van der Lans, Ivo A.; Frewer, Lynn J.

    2012-05-01

    Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such as genetic modification, different socio-psychological factors will potentially influence societal responses to its development and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured interviews with experts on nanotechnology from North West Europe were conducted using repertory grid methodology in conjunction with generalized Procrustes analysis to examine the psychological constructs underlying societal uptake of 15 key applications of nanotechnology drawn from different areas (e.g. medicine, agriculture and environment, chemical, food, military, sports, and cosmetics). Based on expert judgement, the main factors influencing societal response to different applications of nanotechnology will be the extent to which applications are perceived to be beneficial, useful, and necessary, and how 'real' and physically close to the end-user these applications are perceived to be by the public.

  2. Factors influencing autism spectrum disorder screening by community paediatricians

    PubMed Central

    WS, Angie; Zwaigenbaum, Lonnie; Nicholas, David; Sharon, Raphael

    2015-01-01

    BACKGROUND: In most cases, autism spectrum disorders (ASD) can be reliably diagnosed at two to three years of age. However, Canadian data reveal a median age at diagnosis of approximately four years. OBJECTIVE: To examine general paediatricians’ practices regarding ASD screening and identify factors that influence decisions regarding the use of ASD screening tools. METHODS: Using a qualitative inquiry-based interpretive description approach, 12 paediatricians from four practice groups participated in four focus groups and one individual interview. These were conducted using semistructured interviews, digitally recorded and transcribed verbatim. RESULTS: Five main domains of themes were identified related to screening tool use: benefits; needs not addressed; elements that limit utility; elements that encourage utility; and implementation challenges. Factors influencing practice included availability of time, comfort with screening tool use, previous use and knowledge about specific tools. Systemic factors included knowledge and access to community resources, as well as the ability to provide support to the child and family. CONCLUSION: The results from the present study identified important factors that influence paediatric practice in ASD screening. As screening tools improve, it will be important to examine the implementation and effectiveness of screening tools and strategies for increased uptake. Future research will also need to attend to the practical needs of physicians and communities in the aim of earlier diagnosis and rapid access to interventional resources. PMID:26175565

  3. QoS test traffic influence factor analysis

    NASA Astrophysics Data System (ADS)

    Ge, Fei; Cao, Yang

    2004-04-01

    This paper described certain problems when performing QoS active measurement. The term Test Traffic Influence Factor (TTIF), describing quantitatively influence which the test traffic compared to actual traffic on Qos parameters is defined. A kind of ideal model based on the queue theory to study TTIF is build up and a TTIF for delay is discussed. The theoretical analysis results are verified by using network simulation tool-OPNET modeler. Then certain important conclusions and advice about IP network QoS measurement are given and further research direction is directed.

  4. Evidence of Niche Partitioning under Ontogenetic Influences among Three Morphologically Similar Siluriformes in Small Subtropical Streams

    PubMed Central

    Bonato, Karine Orlandi; Fialho, Clarice Bernhardt

    2014-01-01

    Ontogenetic influences in patterns of niche breadth and feeding overlap were investigated in three species of Siluriformes (Heptapterus sp., Rhamdia quelen and Trichomycterus poikilos) aiming at understanding the species coexistence. Samplings were conducted bimonthly by electrofishing technique from June/2012 to June/2013 in ten streams of the northwestern state of Rio Grande do Sul, Brazil. The stomach contents of 1,948 individuals were analyzed by volumetric method, with 59 food items identified. In general Heptapterus sp. consumed a high proportion of Aegla sp., terrestrial plant remains and Megaloptera; R. quelen consumed fish, and Oligochaeta, followed by Aegla sp.; while the diet of T. poikilos was based on Simuliidae, Ephemeroptera and Trichoptera. Specie segregation was observed in the NMDS. Through PERMANOVA analysis feeding differences among species, and between a combination of species plus size classes were observed. IndVal showed which items were indicators of these differences. Niche breadth values were high for all species. The niche breadth values were low only for the larger size of R. quelen and Heptapterus sp. while T. poikilos values were more similar. Overall the species were a low feeding overlap values. The higher frequency of high feeding overlap was observed for interaction between Heptapterus sp. and T. poikilos. The null model confirmed the niche partitioning between the species. The higher frequency of high and intermediate feeding overlap values were reported to smaller size classes. The null model showed resource sharing between the species/size class. Therefore, overall species showed a resource partitioning because of the use of occasional items. However, these species share resources mainly in the early ontogenetic stages until the emphasized change of morphological characteristics leading to trophic niche expansion and the apparent segregation observed. PMID:25340614

  5. The influence of refractory ceramic fibres on pulmonary morphology, redox and immune system in rats.

    PubMed

    Tátrai, Erzsébet; Kováciková, Z; Brózik, M; Six, E; Csík, M; Tulinska, J; Drahos, Agnes; Dám, Annamária

    2006-01-01

    Refractory ceramic fibres (RCF) were studied in male SPRD rats by both in vivo long term sequential and in vitro methods. RCF was administered by single intratracheal instillation and the lungs were examined at the end of months 1, 3 and 6 after exposure. In addition, the direct toxicity of the fibres was examined in a primary culture of alveolar macrophages (AM) and in pneumocytes type II (T2). Pulmonary morphological changes, a number of parameters of the redox system, such as activity of extracellular Cu,Zn/superoxide dismutase (EC-SOD), total glutathione content of the lungs (GSH) and immunoglobulins in bronchoalveolar lavage (IgA, IgG, IgM) and in the blood were measured. The composition of the original RCF and the elemental content of the lung tissue were compared by energy dispersive x-ray analysis (EDXA) before and after exposure. Macrophage alveolitis became confluent and moderate fibrosis developed by the end of month 3, and after 6 months of exposure the intensity decreased to the level of the first month. The RCF did not significantly influence the activity of EC-SOD or the total glutathione content of the lungs. Although aluminium and silicon could be demonstrated by EDXA in the lung tissue at the end of month 3, these elements were no longer detectable by the end of month 6. The RCF decreased IgA significantly in bronchoalveolar lavage (BAL). The main components of RCF induced pulmonary alterations, whereas no significant change could be detected in EC-SOD and GSH. Injuries caused by direct toxicity could be observed in the cell membranes only at the highest concentration. On the basis of these results RCF can be determined as moderately toxic fibres.

  6. The Influence of Contextual and Psychosocial Factors on Handwashing.

    PubMed

    Seimetz, Elisabeth; Boyayo, Anne-Marie; Mosler, Hans-Joachim

    2016-06-01

    Even though washing hands with soap is among the most effective measures to reduce the risk of infection, handwashing rates in infrastructure-restricted settings remain seriously low. Little is known about how context alone and in interaction with psychosocial factors influence hand hygiene behavior. The aim of this article was to explore how both contextual and psychosocial factors affect handwashing practices. A cross-sectional survey was conducted with 660 caregivers of primary school children in rural Burundi. Hierarchical regression analyses revealed that household wealth, the amount of water per person, and having a designated place for washing hands were contextual factors significantly predicting handwashing frequency, whereas the contextual factors, time spent collecting water and amount of money spent on soap, were not significant predictors. The contextual factors explained about 13% of the variance of reported handwashing frequency. The addition of the psychosocial factors to the regression model resulted in a significant 41% increase of explained variation in handwashing frequency. In this final model, the amount of water was the only contextual factor that remained a significant predictor. The most important predictors were a belief of self-efficacy, planning how, when, and where to wash hands, and always remembering to do so. The findings suggest that contextual constraints might be perceived rather than actual barriers and highlight the role of psychosocial factors in understanding hygiene behaviors.

  7. Genetic and environmental factors influencing human diseases with telomere dysfunction

    PubMed Central

    Ly, Hinh

    2009-01-01

    Both genetic and environmental factors have been implicated in the mechanism underlying the pathogenesis of serious and fatal forms of human blood disorder (acquired aplastic anemia, AA) and lung disease (idiopathic pulmonary fibrosis, IPF). We and other researchers have recently shown that naturally occurring mutations in genes encoding the telomere maintenance complex (telomerase) may predispose patients to the development of AA or IPF. Epidemiological data have shown that environmental factors can also cause and/or exacerbate the pathogenesis of these diseases. The exact mechanisms that these germ-line mutations in telomere maintenance genes coupled with environmental insults lead to ineffective hematopoiesis in AA and lung scarring in IPF are not well understood, however. In this article, we provide a summary of evidence for environmental and genetic factors influencing the diseases. These studies provide important insights into the interplay between environmental and genetic factors leading to human diseases with telomere dysfunction. PMID:19684885

  8. Succesful Lean Manufacturing Implementation: Internal Key Influencing Factors

    NASA Astrophysics Data System (ADS)

    Virginia, Iuga; Claudiu, Kifor

    2015-09-01

    Manufacturing sectors and companies all over the world are successfully implementing lean principles within their processes. Nowadays, lean has become an indispensable part of global players. Companies worldwide need to be aware of multiple factors which weigh heavily on the success or failure of lean implementation. This paper focuses on giving a brief and structured overview over the fundamental organizational factors which play a substantial role for the lean manufacturing (LM) implementation process. The study below focuses on internal factors which are indispensable for a successful LM implementation within organizations. It is imperative that these internal factors are known, recognized and taken into consideration during the whole LM implementation process. Ignoring their influence on the process's implementation may lead to endangering the expected results or to making the process more difficult which could result in much higher human resource consumption.

  9. From shared care to disease management: key-influencing factors

    PubMed Central

    Eijkelberg, Irmgard M.J.G.; Spreeuwenberg, Cor; Mur-Veeman, Ingrid M.; Wolffenbuttel, Bruce H.R.

    2001-01-01

    Abstract Background In order to improve the quality of care of chronically ill patients the traditional boundaries between primary and secondary care are questioned. To demolish these boundaries so-called ‘shared care’ projects have been initiated in which different ways of substitution of care are applied. When these projects end, disease management may offer a solution to expand the achieved co-operation between primary and secondary care. Objective Answering the question: What key factors influence the development and implementation of shared care projects from a management perspective and how are they linked? Theory The theoretical framework is based on the concept of the learning organisation. Design Reference point is a multiple case study that finally becomes a single case study. Data are collected by means of triangulation. The studied cases concern two interrelated Dutch shared care projects for type 2 diabetic patients, that in the end proceed as one disease management project. Results In these cases the predominant key-influencing factors appear to be the project management, commitment and local context, respectively. The factor project management directly links the latter two, albeit managing both appear prerequisites to its success. In practice this implies managing the factors' interdependency by the application of change strategies and tactics in a committed and skilful way. Conclusion Project management, as the most important and active key factor, is advised to cope with the interrelationships of the influencing factors in a gradually more fundamental way by using strategies and tactics that enable learning processes. Then small-scale shared care projects may change into a disease management network at a large scale, which may yield the future blueprint to proceed. PMID:16896415

  10. Children's disaster reactions: the influence of family and social factors.

    PubMed

    Pfefferbaum, Betty; Jacobs, Anne K; Houston, J Brian; Griffin, Natalie

    2015-07-01

    This review examines family (demographics, parent reactions and interactions, and parenting style) and social (remote effects, disaster media coverage, exposure to secondary adversities, and social support) factors that influence children's disaster reactions. Lower family socioeconomic status, high parental stress, poor parental coping, contact with media coverage, and exposure to secondary adversities have been associated with adverse outcomes. Social support may provide protection to children in the post-disaster environment though more research is needed to clarify the effects of certain forms of social support. The interaction of the factors described in this review with culture needs further exploration.

  11. Factors influencing the dielectric properties of agricultural and food products.

    PubMed

    Nelson, Stuart O; Trabelsi, Samir

    2012-01-01

    Dielectric properties of materials are defined, and the major factors that influence these properties of agricultural and food materials, namely, frequency of the applied radiofrequency or microwave electric fields, and water content, temperature, and density of the materials, are discussed on the basis of fundamental concepts. The dependence of measured dielectric properties on these factors is illustrated graphically and discussed for a number of agricultural and food products, including examples of grain, peanuts, fruit, eggs, fresh chicken meat, whey protein gel, and a macaroni and cheese preparation. General observations are provided on the nature of the variation of the dielectric properties with the major variables.

  12. The Influence of Various Factors on the Methane Fermentation Process

    NASA Astrophysics Data System (ADS)

    Kurbanova, M. G.; Egushova, E. A.; Pozdnjakova, OG

    2015-09-01

    The article describes the stages of the methane fermentation process. The phases of methane formation are characterized. The results of the experimental data based on the study of various factors influencing the rate of biogas production and its yield are presented. Such factors as the size of the substrate particles and temperature conditions in the reactor are considered. It is revealed on the basis of experimental data which of the farm animals and poultry excrements are exposed to the most complete fermentation without special preparation. The relationship between fermentation regime, particle size of the feedstock and biogas yield is graphically presented.

  13. Metal Oxide Gas Sensors: Sensitivity and Influencing Factors

    PubMed Central

    Wang, Chengxiang; Yin, Longwei; Zhang, Luyuan; Xiang, Dong; Gao, Rui

    2010-01-01

    Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above. PMID:22294916

  14. Influence of dissolved oxygen on the protectiveness and morphological characteristics of calcareous deposits with galvanostatic polarization

    NASA Astrophysics Data System (ADS)

    Li, Chengjie; Du, Min; Gao, Rongjie

    2017-04-01

    The influence of dissolved oxygen on calcareous deposits formed under galvanostatic polarization mode was studied. When the dissolved oxygen concentration was less than 7 mg L-1, the cathodic protection potential showed a plateau at the initial polarization, and then quickly shifted negatively. While the dissolved oxygen was more than 9 mg L-1, the potential shifted negatively in a linear form. After 168 h of polarization, the final protection potential shifted negatively with the decreasing dissolved oxygen concentration. The deposition progress was monitored by electrochemical impedance spectroscopy, and only one single loop was found in Nyquist diagram, indicating deposits of ineffective protectiveness precipitation under the experimental conditions. The protection factor of deposits increased with the decreasing dissolved oxygen concentration which was detected by linear polarization resistance technique. The cathodic electrochemical reaction could change very shortly from oxygen reduction to hydrogen evolution after cathodic protection under very low dissolved oxygen concentration, such as 1 mg L-1, resulting in the hydrogen bubbling from the metallic surface and the decrease of deposits protection factor. Observation by scanning electron microscopy and X-ray diffraction analysis demonstrated that the deposits were mainly of calcite under the experimental conditions, and that dissolved oxygen had no effect on the crystalline types of calcium carbonate.

  15. Influence of geophysical factors on oblique-sounder ionospheric characteristics

    SciTech Connect

    Baranets, A.N.; Blagoveshchenskaya, N.F.; Borisova, T.D.; Bubnov, V.A.

    1988-10-01

    The purpose of this paper is to study the influence of geophysical factors, including magnetoionospheric disturbances, on decameter wave propagation over extended paths using oblique sounding (OS) data, and also to compare experimental and calculated OS ionograms for various conditions of radio waver propagation (season, time of day). Variations of oblique-sounder ionospheric characteristics along a 9000 km long subauroral path for various geophysical conditions are considered. A comparison is made of experimental and calculated ionograms of oblique sounding.

  16. Foundation doctors career choice and factors influencing career choice.

    PubMed

    Wiener-Ogilvie, Sharon; Begg, Drummond; Dixon, Guy

    2015-11-01

    This study is seeking to establish the factors influencing foundation doctors' decision-making when applying for speciality training. A questionnaire was sent to all foundation doctors in Scotland (n = 1602, response rate 34%) asking them about their career intention in relation to General Practice, whether they received career advice and the extent to which certain factors influenced their career choice. For the majority of trainees, General Practice was not their first choice but just under half were considering it as a career. There were significant differences in career choices between the four Scottish regions and between the medical schools, with a greater proportion of those who studied in Aberdeen and Dundee Medical Schools opting for a career in General Practice. Undergraduate GP placement was reported as the strongest influence in favour of a career in General Practice followed by discussion with family and friends and discussion with speciality trainees. There were differences between medical schools in the way hospital placements, General Practice placements and role models influenced career choices. Career advice on General Practice was reported to be less available and more difficult to find.

  17. Factors influencing veterinary students career choices and attitudes to animals.

    PubMed

    Serpell, James A

    2005-01-01

    The purpose of the study was to investigate the influence of demographic and experiential factors on first-year veterinary students career choices and attitudes to animal welfare/rights. The study surveyed 329 first-year veterinary students to determine the influence of demographic factors, farm experience, and developmental exposure to different categories of animals on their career preferences and on their attitudes to specific areas of animal welfare and/or rights. A significant male gender bias toward food-animal practice was found, and prior experience with particular types of animals--companion animals, equines, food animals--tended to predict career preferences. Female veterinary students displayed greater concern for possible instances of animal suffering than males, and prior experience with different animals, as well as rural background and farm experience, were also associated with attitude differences. Seventy-two percent of students also reported that their interactions with animals (especially pets) had strongly influenced the development of their values. Animals ranked second in importance after parents in this respect. The present findings illustrate the importance to issues of animal welfare of the cultural context of past experience and influences on attitude development. The results also suggest that previous interactions with animals play a critical role in guiding veterinary students into their chosen career, as well as in helping to determine their specific employment preferences within the veterinary profession. From an animal welfare perspective, the dearth of women choosing careers in food-animal practice is a source of concern.

  18. Factors influencing the publishing efforts of graduate students in nursing.

    PubMed

    Whitley, G G; Oddi, L F; Terrell, D

    1998-04-01

    The purposes of this study were to identify factors influencing publication efforts of graduate students in nursing and determine the extent to which graduate students' scholarly activities contribute to the creation and dissemination of knowledge in nursing, as evidenced by publication in a professional journal. Authors of articles in Nursing Research were surveyed to assess their status as graduate students during the conceptualization, development, and publication of nursing research studies. The sample consisted of 633 authors of manuscripts published in Nursing Research from 1987 to 1991. The study design was descriptive. A survey questionnaire elicited data on graduate student status and factors that influenced the initiation and completion of the project. The data were analyzed using descriptive statistical techniques. The results of the study suggest that graduate students in nursing make important contributions to the advancement and dissemination of nursing knowledge. Factors that influence graduate students to engage in the process include academic requirements (e.g., thesis, dissertation, coursework), faculty involvement and support, and the ability to self-select the research topic.

  19. Research on Factors Influencing Individual's Behavior of Energy Management

    NASA Astrophysics Data System (ADS)

    Fan, Yanfeng

    With the rapid rise of distributed generation, Internet of Things, and mobile Internet, both U.S. and European smart home manufacturers have developed energy management solutions for individual usage. These applications help people manage their energy consumption more efficiently. Domestic manufacturers have also launched similar products. This paper focuses on the factors influencing Energy Management Behaviour (EMB) at the individual level. By reviewing academic literature, conducting surveys in Beijing, Shanghai and Guangzhou, the author builds an integrated behavioural energy management model of the Chinese energy consumers. This paper takes the vague term of EMB and redefines it as a function of two separate behavioural concepts: Energy Management Intention (EMI), and the traditional Energy Saving Intention (ESI). Secondly, the author conducts statistical analyses on these two behavioural concepts. EMI is the main driver behind an individual's EMB. EMI is affected by Behavioural Attitudes, Subjective Norms, and Perceived Behavioural Control (PBC). Among these three key factors, PBC exerts the strongest influence. This implies that the promotion of the energy management concept is mainly driven by good application user experience (UX). The traditional ESI also demonstrates positive influence on EMB, but its impact is weaker than the impacts arising under EMI's three factors. In other words, the government and manufacturers may not be able to change an individual's energy management behaviour if they rely solely on their traditional promotion strategies. In addition, the study finds that the government may achieve better promotional results by launching subsidies to the manufacturers of these kinds of applications and smart appliances.

  20. A real-time assessment of factors influencing medication events.

    PubMed

    Dollarhide, Adrian W; Rutledge, Thomas; Weinger, Matthew B; Fisher, Erin Stucky; Jain, Sonia; Wolfson, Tanya; Dresselhaus, Timothy R

    2014-01-01

    Reducing medical error is critical to improving the safety and quality of healthcare. Physician stress, fatigue, and excessive workload are performance-shaping factors (PSFs) that may influence medical events (actual administration errors and near misses), but direct relationships between these factors and patient safety have not been clearly defined. This study assessed the real-time influence of emotional stress, workload, and sleep deprivation on self-reported medication events by physicians in academic hospitals. During an 18-month study period, 185 physician participants working at four university-affiliated teaching hospitals reported medication events using a confidential reporting application on handheld computers. Emotional stress scores, perceived workload, patient case volume, clinical experience, total sleep, and demographic variables were also captured via the handheld computers. Medication event reports (n = 11) were then correlated with these demographic and PSFs. Medication events were associated with 36.1% higher perceived workload (p < .05), 38.6% higher inpatient caseloads (p < .01), and 55.9% higher emotional stress scores (p < .01). There was a trend for reported events to also be associated with less sleep (p = .10). These results confirm the effect of factors influencing medication events, and support attention to both provider and hospital environmental characteristics for improving patient safety.

  1. Morphological and microsatellite diversity associated with ecological factors in natural populations of Medicago laciniata Mill. (Fabaceae).

    PubMed

    Badri, Mounawer; Zitoun, Adel; Ilahi, Houcine; Huguet, Thierry; Aouani, Mohamed Elarbi

    2008-12-01

    Genetic variability in 10 natural Tunisian populations of Medicago laciniata were analysed using 19 quantitative traits and 12 polymorphic microsatellite loci. A large degree of genetic variability within-populations and among-populations was detected for both quantitative characters and molecular markers. High genetic differentiation among populations for quantitative traits was seen, with Q(ST) = 0.47, and F(ST) = 0.47 for microsatellite markers. Several quantitative traits displayed no statistical difference in the levels of Q(ST) and F(ST). Further, significant correlations between quantitative traits and eco-geographical factors suggest that divergence in the traits among populations may track environmental differences. There was no significant correlation between genetic variability at quantitative traits and microsatellite markers within populations. The site-of-origin of eco-geographical factors explain between 18.13% and 23.40% of genetic variance among populations at quantitative traits and microsatellite markers, respectively. The environmental factors that most influence variation in measured traits among populations are assimilated phosphorus (P(2)0(5)) and mean annual rainfall, followed by climate and soil texture, altitude and organic matter. Significant associations between eco-geographical factors and gene diversity, He, were established in five microsatellite loci suggesting that these simple sequence repeats (SSRs) are not necessarily biologically neutral.

  2. Influence of surface morphology and microstructure on performance of CVD tungsten coating under fusion transient thermal loads

    NASA Astrophysics Data System (ADS)

    Lian, Youyun; Liu, Xiang; Wang, Jianbao; Feng, Fan; Lv, Yanwei; Song, Jiupeng; Chen, Jiming

    2016-12-01

    Thick tungsten coatings have been deposited by chemical vapor deposition (CVD) at a rapid growth rate. A series of tungsten coatings with different thickness and surface morphology were prepared. The surface morphology, microstructure and preferred orientation of the CVD tungsten coatings were investigated. Thermal shock analyses were performed by using an electron beam facility to study the influence of the surface morphology and the microstructure on the thermal shock resistance of the CVD tungsten coatings. Repetitive (100 pulses) ELMs-like thermal shock loads were applied at various temperatures between room temperature and 600 °C with pulse duration of 1 ms and an absorbed power density of up to 1 GW/m2. The results of the tests demonstrated that the specific surface morphology and columnar crystal structure of the CVD tungsten have significant influence on the surface cracking threshold and crack propagation of the materials. The CVD tungsten coatings with a polished surface show superior thermal shock resistance as compared with that of the as-deposited coatings with a rough surface.

  3. Genetic and pharmacological factors that influence reproductive aging in nematodes.

    PubMed

    Hughes, Stacie E; Evason, Kimberley; Xiong, Chengjie; Kornfeld, Kerry

    2007-02-16

    Age-related degenerative changes in the reproductive system are an important aspect of aging, because reproductive success is the major determinant of evolutionary fitness. Caenorhabditis elegans is a prominent organism for studies of somatic aging, since many factors that extend adult lifespan have been identified. However, mechanisms that control reproductive aging in nematodes or other animals are not well characterized. To use C. elegans to measure reproductive aging, we analyzed mated hermaphrodites that do not become sperm depleted and monitored the duration and level of progeny production. Mated hermaphrodites display a decline of progeny production that culminates in reproductive cessation before the end of the lifespan, demonstrating that hermaphrodites undergo reproductive aging. To identify factors that influence reproductive aging, we analyzed genetic, environmental, and pharmacological factors that extend lifespan. Dietary restriction and reduced insulin/insulin-like growth factor signaling delayed reproductive aging, indicating that nutritional status and a signaling pathway that responds to environmental stress influence reproductive aging. Cold temperature delayed reproductive aging. The anticonvulsant medicine ethosuximide, which affects neural activity, delayed reproductive aging, indicating that neural activity can influence reproductive aging. Some of these factors decrease early progeny production, but there is no consistent relationship between early progeny production and reproductive aging in strains with an extended lifespan. To directly examine the effects of early progeny production on reproductive aging, we used sperm availability to modulate the level of early reproduction. Early progeny production neither accelerated nor delayed reproductive aging, indicating that reproductive aging is not controlled by use-dependent mechanisms. The implications of these findings for evolutionary theories of aging are discussed.

  4. Factors Potentially Influencing Student Acceptance of Biological Evolution

    NASA Astrophysics Data System (ADS)

    Wiles, Jason R.

    This investigation explored scientific, religious, and otherwise nonscientific factors that may influence student acceptance of biological evolution and related concepts, how students perceived these factors to have influenced their levels of acceptance of evolution and changes therein, and what patterns arose among students' articulations of how their levels of acceptance of evolution may have changed. This exploration also measured the extent to which students' levels of acceptance changed following a treatment designed to address factors identified as potentially affecting student acceptance of evolution. Acceptance of evolution was measured using the MATE instrument (Rutledge and Warden, 1999; Rutledge and Sadler, 2007) among participants enrolled in a secondary-level academic program during the summer prior to their final year of high school and as they transitioned to the post-secondary level. Student acceptance of evolution was measured to be significantly higher than pre-treatment levels both immediately following and slightly over one year after treatment. Qualitative data from informal questionnaires, from formal course evaluations, and from semi-structured interviews of students engaged in secondary level education and former students at various stages of post-secondary education confirmed that the suspected factors were perceived by participants to have influenced their levels of acceptance of evolution. Furthermore, participant reports provided insight regarding the relative effects they perceived these factors to have had on their evolution acceptance levels. Additionally, many participants reported that their science teachers in public schools had avoided, omitted, or denigrated evolution during instruction, and several of these students expressed frustration regarding what they perceived to have been a lack of education of an important scientific principle. Finally, no students expressed feelings of being offended by having been taught about

  5. Influence of Landscape Morphology and Vegetation Cover on the Sampling of Mixed Igneous Bodies

    NASA Astrophysics Data System (ADS)

    Perugini, Diego; Petrelli, Maurizio; Poli, Giampiero

    2010-05-01

    cover is generated using a random Brownian motion process in 2D. Such an approach allows us to produce vegetation patches that closely match the general topology of natural vegetation (e.g., Mandelbrot, 1982). Results show that the goodness of sampling is strongly dependant on the roughness of the landscape, with highly irregular morphologies being the best candidates to give the most complete information on the whole magma body. Conversely, sampling on flat or nearly flat surfaces should be avoided because they may contain misleading information about the magmatic system. Contrary to common sense, vegetation cover does not appear to significantly influence the representativeness of sampling if sample collection occurs on topographically irregular outcrops. Application of the proposed method for sampling area selection is straightforward. The irregularity of natural landscapes and the percentage of vegetation can be estimated by using natural landscapes extracted from digital elevation models (DEM) of the Earth's surface and satellite images by employing a variety of methods (e.g., Develi and Babadagli, 1998), thus giving one the opportunity to select a priori the best outcrops for sampling. References Bateman R (1995) The interplay between crystallization, replenishment and hybridization in large felsic magma chambers. Earth Sci Rev 39: 91-106 Develi K, Babadagli T (1998) Quantfication of natural fracture surfaces using fractal geometry. Math Geol 30: 971-998 Fournier A, Fussel D, Carpenter L (1982) Computer rendering of stochastic models. Comm ACM 25: 371-384 Galluccio S, Vulpiani A (1994) Stretching of material lines and surfaces in systems with Lagrangian chaos. Physica A 212: 75-98 Mandelbrot BB (1982) The fractal geometry of nature. W. H. Freeman, San Francisco Perugini D, Petrelli M, Poli G (2007) A Virtual Voyage through 3D Structures Generated by Chaotic Mixing of Magmas and Numerical Simulations: a New Approach for Understanding Spatial and Temporal Complexity

  6. Influence Of The Microinjection Moulding Process On The Crystalline Orientation And Morphology Of Semicrystalline Polymers

    NASA Astrophysics Data System (ADS)

    Malhab, Nada Bou; Régnier, Gilles

    2011-05-01

    Microinjection moulding (μIM) seems to be a key for the large scale production of polymer microparts. For semicrystalline polymers, the crystallisation under high shear and cooling rates induces specific morphologies and properties and thus takes tremendous importance in microinjection process compared to classical injection moulding (IM) process where wall thicknesses are generally larger than 1mm. Two semicrystalline polymers were microinjected, a high density polyethylene and a polyamide 12 in plaque cavities having thicknesses of 0.3 and 0.5mm. Analyses obtained by optical microscopy show that the crystalline morphologies vary between micro- and macro- parts. While a `skin-core' morphology is present for the macropart, the μpart exhibits a specific morphology. The X-ray scattering at small angles (SAXS) studies show an orientation of HDPE lamellae whatever the conditions of microinjection whereas the orientation of PA12 lamellae is either isotropic or anisotropic depending on the thickness of molded parts.

  7. Effects of basic fibroblast growth factor on density and morphology of fibroblasts grown on root surfaces with or without conditioning with tetracycline or EDTA.

    PubMed

    Silvério, Karina G; Martinez, Aurora E T; Rossa, Carlos

    2007-09-01

    A study was conducted to evaluate in vitro the effect of root surface conditioning with basic fibroblast growth factor (b-FGF) on morphology and proliferation of fibroblasts. Three experimental groups were used: non-treated, and treated with 50 microg or 125 microg b-FGF/ml. The dentin samples in each group were divided into subgroups according to the chemical treatment received before application of b-FGF: none, or conditioned with tetracycline-HCl or EDTA. After contact with b-FGF for 5 min, the samples were incubated for 24 h with 1 ml of culture medium containing 1 x 10(5) cells/ml plus 1 ml of culture medium alone. The samples were then subjected to routine preparation for SEM, and random fields were photographed. Three calibrated and blind examiners performed the assessment of morphology and density according to two index systems. Classification and regression trees indicated that the root surfaces treated with 125 microg b-FGF and previously conditioned with tetracycline-HCl or EDTA presented a morphology more suggestive of cellular adhesion and viability (P = 0.004). The density of fibroblasts on samples previously conditioned with EDTA, regardless of treatment with b-FGF, was significantly higher than in the other groups (P < 0.001). The present findings suggest that topical application of b-FGF has a positive influence on both the density and morphology of fibroblasts.

  8. Study of factors which influence the shock-initiation sensitivity of hexanitrostilbene (HNS)

    SciTech Connect

    Schwarz, A. C.

    1981-03-01

    An experimental program was conducted to study factors which influence the shock initiation sensitivity of hexanitrostilbene (HNS). The six factors evaluated were: (1) powder morphology, (2) sample density, (3) test temperature, (4) sample length, (5) diameter of the impacting flyer, and (6) duration of the input stimulus. In addition, the effect of pressure duration, tau, was assessed on the initiation sensitivity of an extrudable explosive (LX-13) and of hexanitroazobenzene (HNAB) for comparison with that of superfine hexanitrostilbene (HNS-SF). The impact stimulus was provided by a polyimide flyer 1.57 mm in diameter propelled by an electrically excited bursting foil. Flyer velocity determined impact pressure, P (3 to 20 GPa), and flyer thickness the shock duration, tau (0.010 to 0.150 ..mu..s), the pulse shape being rectangular. Powder morphology was the most significant factor to influence the initiation sensitivity of HNS; with 0.035-..mu..s pulses the smallest particle-sized HNS had a threshold pressure for initiation which was 50% of that required for the coarser HNS-II. Other factors which lowered the threshold pressure were: lower sample density, elevated test temperature, and larger diameter flyers. HNS-SF showed a shorter growth-to-detonation distance (GTDD) than HNS-I; the GTDD was 0.56 mm at an impact pressure of 7.3 GPa. Pulse duration affected the threshold pressure with each explosive behaving in its own characteristic manner; a P-tau characterization is essential, therefore, for all explosives of interest and should include values of tau which are equivalent to pulse durations expected in service.

  9. The influence of collagen support and ionic species on the morphology of collagen/hydroxyapatite composite materials

    SciTech Connect

    Ficai, Anton; Andronescu, Ecaterina; Voicu, Georgeta; Ghitulica, Cristina; Ficai, Denisa

    2010-04-15

    The purpose of this investigation is to study the influence of collagenous supports and ionic species on the precipitation of hydroxyapatite (HA) from aqueous solutions. To this end, we obtained hydroxyapatite by co-precipitation from a solution of calcium hydroxide and sodium dihydrogenophosphate. The formation of HA was studied by energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results of this study indicate that the morphology of hydroxyapatite is highly influenced by the support material and the ionic species present. The obtained materials were studied by scanning electron microscopy (SEM).

  10. Personal and situational factors influencing coaches' perceptions of stress.

    PubMed

    Knight, Camilla J; Reade, Ian L; Selzler, Anne-Marie; Rodgers, Wendy M

    2013-01-01

    Coaching has been recognised as a demanding occupation, associated with a range of stressors. The extent to which coaches perceive stress is likely to be influenced by various personal and situational factors. The purpose of this study was to identify coaches' levels of perceived stress and examine the personal and situational factors that may influence coaches' perceptions of stress. In total, 502 coaches working with university, college, Canada Games, and/or nationally identified athletes completed this study. Coaches completed an online survey, which included questions regarding demographics, work/job-related considerations, and aspects relating to their contract. Coaches also completed the Perceived Stress Scale (Cohen, Kamarck, & Mermelstein, 1983). Overall coaches indicated slightly below average levels of perceived stress (M = 15.13 out of 40) compared with norm-values (Cohen & Janicki-Deverts, 2012). Demographic factors, job-related characteristics, and certain aspects of their contract were associated with coaches' perceptions of stress. In particular, unclear expectations, long-working hours (>40), lack of agreed evaluation criteria, higher salaries, and a lack of social support were related to higher perceptions of stress. As such, the findings of the current study indicate that a reduction in perceived stress is likely to be achieved through a multifaceted approach that addresses multiple factors associated with coaching.

  11. Factors influencing palliative care. Qualitative study of family physicians' practices.

    PubMed Central

    Brown, J. B.; Sangster, M.; Swift, J.

    1998-01-01

    OBJECTIVE: To examine factors that influence family physicians' decisions to practise palliative care. DESIGN: Qualitative method of in-depth interviews. SETTING: Southwestern Ontario. PARTICIPANTS: Family physicians who practise palliative care on a full-time basis, who practise on a part-time basis, or who have retired from active involvement in palliative care. METHOD: Eleven in-depth interviews were conducted to explore factors that influence family physicians' decisions to practise palliative care and factors that sustain their interest in palliative care. All interviews were audiotaped and transcribed verbatim. The analysis strategy used a phenomenological approach and occurred concurrently rather than sequentially. All interview transcriptions were read independently by the researchers, who then compared and combined their analyses. Final analysis involved examining all interviews collectively, thus permitting relationships between and among central themes to emerge. MAIN OUTCOME FINDINGS: The overriding theme was a common philosophy of palliative care focusing on acceptance of death, whole person care, compassion, communication, and teamwork. Participants' philosophies were shaped by their education and by professional and personal experiences. In addition, participants articulated personal and systemic factors currently affecting their practice of palliative care. CONCLUSIONS: Participants observed that primary care physicians should be responsible for their patients' palliative care within the context of interdisciplinary teams. For medical students to be knowledgeable and sensitive to the needs of dying patients, palliative care should be given higher priority in the curriculum. Finally, participants argued compellingly for transferring the philosophy of palliative care to the overall practice of medicine. PMID:9612588

  12. Influence of Beach Scraping on Beach Profile Morphology: Fire Island, New York

    NASA Astrophysics Data System (ADS)

    Kratzmann, M.; Hapke, C.

    2007-12-01

    Fire Island is part of a barrier island system located just south of Long Island, New York. The island is 50 km long, oriented southwest-northeast, and varies in width from 150 meters to 1 kilometer. Established communities on Fire Island are part of Fire Island National Seashore (FIIS) which is managed by the National Park Service. The island is densely populated, and thus mitigating coastal erosion caused by large-scale storm waves has become an important issue. Severe nor'easter storms in 1991, 1992, and 1993 caused substantial erosion and property damage. This prompted communities within FIIS to conduct a pilot study in which the preventative, non-structural practice of beach scraping was employed as a method of erosion control. Beach scraping is the anthropogenic movement of sand from the berm to the back beach creating an artificial foredune. Currently, there is no published research that explores the morphologic influence of beach scraping on Fire Island, although the practice is still in place today for a number of communities. This study assesses changes caused by beach scraping using a temporally robust beach profile dataset of over 150 profiles, spanning thirteen years. Three study areas were chosen based on location (western, central, and eastern parts of Fire Island) and data availability in scraped and adjacent control areas. Analyzed characteristics include beach width, beach volume, slope (dune, beachface, global), berm crest elevation, and dune crest elevation. Initial results indicate a detectable difference in the behavior of the beach between scraped and control areas. Seasonal signals show beach width decreasing substantially westward from the scraped profile location, which is in the direction of net littoral transport. Anthropogenic relocation of berm material to the foredune zone during scraping places sediment in the back beach area that might otherwise be mobilized by storm waves, therefore depriving downcoast beaches of sediment. Longer

  13. Influence factors affecting career choice of preclinical medical technology students.

    PubMed

    Gleich, C

    1978-06-01

    Over a seven-year period, data were gathered on 249 declared medical technology majors enrolled in an Introduction to Medical Technology course at the University of Iowa. The Kendall Tau C test for significance (p = less than .05) was utilized in determining the influence of several variables or factors in the students' choice of medical technology as a career. Such factors as the type of work, demand for medical technologists, and desire to help people were found to be highly motivating factors in choice. It appeared the motivation was primarily internalized with assistance sought from various sources. The decision of medical technology as a career was predominantly made in the junior/senior year in high school or freshman/sophomore year in college.

  14. A review on factors influencing bioaccessibility and bioefficacy of carotenoids.

    PubMed

    Priyadarshani, A M B

    2017-05-24

    Vitamin A deficiency is one of the most prevalent deficiency disorders in the world. As shown by many studies plant food based approaches have a real potential on prevention of vitamin A deficiency in a sustainable way. Carotenoids are important as precursors of vitamin A as well as for prevention of cancers, coronary heart diseases, age-related macular degeneration, cataract etc. Bioaccessibility and bioefficacy of carotenoids are known to be influenced by numerous factors including dietary factors such as fat, fiber, dosage of carotenoid, location of carotenoid in the plant tissue, heat treatment, particle size of food, carotenoid species, interactions among carotenoids, isomeric form and molecular linkage and subject characteristics. Therefore even when carotenoids are found in high quantities in plant foods their utilization may be unsatisfactory because some factors are known to interfere as negative effectors.

  15. Pharmacokinetic, Pharmacogenetic, and Other Factors Influencing CNS Penetration of Antiretrovirals

    PubMed Central

    Babalola, Chinedum Peace; Morse, Gene D.; Taiwo, Babafemi

    2016-01-01

    Neurological complications associated with the human immunodeficiency virus (HIV) are a matter of great concern. While antiretroviral (ARV) drugs are the cornerstone of HIV treatment and typically produce neurological benefit, some ARV drugs have limited CNS penetration while others have been associated with neurotoxicity. CNS penetration is a function of several factors including sieving role of blood-brain and blood-CSF barriers and activity of innate drug transporters. Other factors are related to pharmacokinetics and pharmacogenetics of the specific ARV agent or mediated by drug interactions, local inflammation, and blood flow. In this review, we provide an overview of the various factors influencing CNS penetration of ARV drugs with an emphasis on those commonly used in sub-Saharan Africa. We also summarize some key associations between ARV drug penetration, CNS efficacy, and neurotoxicity. PMID:27777797

  16. [Factors influencing self-perception of overweight people].

    PubMed

    Makara-Studzińska, Marta; Podstawka, Danuta; Goclon, Karolina

    2013-11-01

    Shaping of self-perception is among others influenced by physical, interpersonal, emotional, and cultural factors. In self-perception of overweight people an important role is played by interpersonal factors, which include the opinions of others and the relationship with the surrounding. The evaluation of the body image is also affect by sociocultural factors including the media, which create an unrealistic and impossible to achieve ideal of beauty. Contemporary ideal of beauty, where a slim figure is dominant, more frequently contributes to the occurrence of discrimination and stigmatization of overweight people. This phenomenon causes negative self-perception leading to the occurrence of such emotional problems as low self-esteem, lack of confidence, depression and anxiety disorders. Overweight children and adolescents are also frequently stigmatized and discriminated because of their body weight, which results in the development of a negative body image that may lead to low self-esteem and symptoms of depression.

  17. Factors influencing Malaysian public attitudes to agro-biotechnology.

    PubMed

    Amin, Latifah; Ahmad, Jamil; Jahi, Jamaluddin Md; Nor, Abd Rahim Md; Osman, Mohamad; Mahadi, Nor Muhammad

    2011-09-01

    Despite considerable research in advanced countries on public perceptions of and attitudes to modern biotechnology, limited effort has been geared towards developing a structural model of public attitudes to modern biotechnology. The purpose of this paper is to identify the relevant factors influencing public attitudes towards genetically modified (GM) soybean, and to analyze the relationship between all the attitudinal factors. A survey was carried out on 1,017 respondents from various stakeholder groups in the Klang Valley region. Results of the survey have confirmed that attitudes towards complex issues such as biotechnology should be seen as a multifaceted process. The most important factors predicting support for GM soybean are the specific application-linked perceptions about the benefits, acceptance of risk and moral concern while risk and familiarity are significant predictors of benefit and risk acceptance. Attitudes towards GM soybean are also predicted by several general classes of attitude.

  18. Advances in principal factors influencing carbon dioxide adsorption on zeolites

    PubMed Central

    Bonenfant, Danielle; Kharoune, Mourad; Niquette, Patrick; Mimeault, Murielle; Hausler, Robert

    2008-01-01

    We report the advances in the principal structural and experimental factors that might influence the carbon dioxide (CO2) adsorption on natural and synthetic zeolites. The CO2 adsorption is principally govern by the inclusion of exchangeable cations (countercations) within the cavities of zeolites, which induce basicity and an electric field, two key parameters for CO2 adsorption. More specifically, these two parameters vary with diverse factors including the nature, distribution and number of exchangeable cations. The structure of framework also determines CO2 adsorption on zeolites by influencing the basicity and electric field in their cavities. In fact, the basicity and electric field usually vary inversely with the Si/Al ratio. Furthermore, the CO2 adsorption might be limited by the size of pores within zeolites and by the carbonates formation during the CO2 chemisorption. The polarity of molecules adsorbed on zeolites represents a very important factor that influences their interaction with the electric field. The adsorbates that have the most great quadrupole moment such as the CO2, might interact strongly with the electric field of zeolites and this favors their adsorption. The pressure, temperature and presence of water seem to be the most important experimental conditions that influence the adsorption of CO2. The CO2 adsorption increases with the gas phase pressure and decreases with the rise of temperature. The presence of water significantly decreases adsorption capacity of cationic zeolites by decreasing strength and heterogeneity of the electric field and by favoring the formation of bicarbonates. The optimization of the zeolites structural characteristics and the experimental conditions might enhance substantially their CO2 adsorption capacity and thereby might give rise to the excellent adsorbents that may be used to capturing the industrial emissions of CO2. PMID:27877925

  19. Factors Influencing Learning Environments in an Integrated Experiential Program

    NASA Astrophysics Data System (ADS)

    Koci, Peter

    The research conducted for this dissertation examined the learning environment of a specific high school program that delivered the explicit curriculum through an integrated experiential manner, which utilized field and outdoor experiences. The program ran over one semester (five months) and it integrated the grade 10 British Columbian curriculum in five subjects. A mixed methods approach was employed to identify the students' perceptions and provide richer descriptions of their experiences related to their unique learning environment. Quantitative instruments were used to assess changes in students' perspectives of their learning environment, as well as other supporting factors including students' mindfulness, and behaviours towards the environment. Qualitative data collection included observations, open-ended questions, and impromptu interviews with the teacher. The qualitative data describe the factors and processes that influenced the learning environment and give a richer, deeper interpretation which complements the quantitative findings. The research results showed positive scores on all the quantitative measures conducted, and the qualitative data provided further insight into descriptions of learning environment constructs that the students perceived as most important. A major finding was that the group cohesion measure was perceived by students as the most important attribute of their preferred learning environment. A flow chart was developed to help the researcher conceptualize how the learning environment, learning process, and outcomes relate to one another in the studied program. This research attempts to explain through the consideration of this case study: how learning environments can influence behavioural change and how an interconnectedness among several factors in the learning process is influenced by the type of learning environment facilitated. Considerably more research is needed in this area to understand fully the complexity learning

  20. Factors influencing U.S. canine heartworm (Dirofilaria immitis) prevalence

    PubMed Central

    2014-01-01

    Background This paper examines the individual factors that influence prevalence rates of canine heartworm in the contiguous United States. A data set provided by the Companion Animal Parasite Council, which contains county-by-county results of over nine million heartworm tests conducted during 2011 and 2012, is analyzed for predictive structure. The goal is to identify the factors that are important in predicting high canine heartworm prevalence rates. Methods The factors considered in this study are those envisioned to impact whether a dog is likely to have heartworm. The factors include climate conditions (annual temperature, precipitation, and relative humidity), socio-economic conditions (population density, household income), local topography (surface water and forestation coverage, elevation), and vector presence (several mosquito species). A baseline heartworm prevalence map is constructed using estimated proportions of positive tests in each county of the United States. A smoothing algorithm is employed to remove localized small-scale variation and highlight large-scale structures of the prevalence rates. Logistic regression is used to identify significant factors for predicting heartworm prevalence. Results All of the examined factors have power in predicting heartworm prevalence, including median household income, annual temperature, county elevation, and presence of the mosquitoes Aedes trivittatus, Aedes sierrensis and Culex quinquefasciatus. Interactions among factors also exist. Conclusions The factors identified are significant in predicting heartworm prevalence. The factor list is likely incomplete due to data deficiencies. For example, coyotes and feral dogs are known reservoirs of heartworm infection. Unfortunately, no complete data of their populations were available. The regression model considered is currently being explored to forecast future values of heartworm prevalence. PMID:24906567

  1. Factors influencing smokeless tobacco use in rural Ohio Appalachia.

    PubMed

    Nemeth, Julianna M; Liu, Sherry T; Klein, Elizabeth G; Ferketich, Amy K; Kwan, Mei-Po; Wewers, Mary Ellen

    2012-12-01

    The burden of smokeless tobacco (ST) use disproportionally impacts males in rural Ohio Appalachia. The purpose of this study was to describe the cultural factors contributing to this disparity and to articulate the way in which culture, through interpersonal factors (i.e. social norms and social networks) and community factors (i.e. marketing and availability), impacts ST initiation and use of ST among boys and men in Ohio Appalachia. Fifteen focus groups and 23 individual qualitative interviews were conducted with adult (n = 63) and adolescent (n = 53) residents in Ohio Appalachian counties to ascertain factors associated with ST use and the impact of ST marketing. Transcriptions were independently coded according to questions and themes. ST use appears to be a rite of passage in the development of masculine identity in Ohio Appalachian culture. Interpersonal factors had the greatest influence on initiation and continued use of ST. Ohio Appalachian boys either emulated current ST users or were actively encouraged to use ST through male family and peer networks. Users perceived their acceptance into the male social network as predicated on ST use. Community factors, including ST advertisement and access to ST, reinforced and normalized underlying cultural values. In addition to policy aimed at reducing tobacco marketing and access, interventions designed to reduce ST use in Ohio Appalachia should incorporate efforts to (1) shift the perception of cultural norms regarding ST use and (2) address male social networks as vehicles in ST initiation.

  2. The influence of tree morphology on stemflow generation in a tropical lowland rainforest

    NASA Astrophysics Data System (ADS)

    Uber, Magdalena; Levia, Delphis F.; Zimmermann, Beate; Zimmermann, Alexander

    2014-05-01

    Even though stemflow usually accounts for only a small proportion of rainfall, it is an important point source of water and ion input to forest floors and may, for instance, influence soil moisture patterns and groundwater recharge. Previous studies showed that the generation of stemflow depends on a multitude of meteorological and biological factors. Interestingly, despite the tremendous progress in stemflow research during the last decades it is still largely unknown which combination of tree characteristics determines stemflow volumes in species-rich tropical forests. This knowledge gap motivated us to analyse the influence of tree characteristics on stemflow volumes in a 1 hectare plot located in a Panamanian lowland rainforest. Our study comprised stemflow measurements in six randomly selected 10 m by 10 m subplots. In each subplot we measured stemflow of all trees with a diameter at breast height (DBH) > 5 cm on an event-basis for a period of six weeks. Additionally, we identified all tree species and determined a set of tree characteristics including DBH, crown diameter, bark roughness, bark furrowing, epiphyte coverage, tree architecture, stem inclination, and crown position. During the sampling period, we collected 985 L of stemflow (0.98 % of total rainfall). Based on regression analyses and comparisons among plant functional groups we show that palms were most efficient in yielding stemflow due to their large inclined fronds. Trees with large emergent crowns also produced relatively large amounts of stemflow. Due to their abundance, understory trees contribute much to stemflow yield not on individual but on the plot scale. Even though parameters such as crown diameter, branch inclination and position of the crown influence stemflow generation to some extent, these parameters explain less than 30 % of the variation in stemflow volumes. In contrast to published results from temperate forests, we did not detect a negative correlation between bark roughness

  3. Morphological and Molecular Characterization of Pomegranate Fruit Rot Pathogen, Chaetomella raphigera, and its Virulence Factors.

    PubMed

    Gajbhiye, Milind; Sathe, Shivaji; Shinde, Vikas; Kapadnis, Balu

    2016-03-01

    A new fungal pathogen was isolated from rotten pomegranates collected from the orchards of different parts of Maharashtra. The pathogen was morphologically identified as Chaetomella raphigera followed by sequencing of ITS and D1/D2 hypervariable region of LSU (28S) of rRNA gene. The pathogen produced pectinase, cellulase, xylanase and protease in liquid medium at a concentration of 71, 13.8, 54.3 and 7 U/ml respectively. Enzyme activity was also determined during pathogenesis in the tissues artificially infected by C. raphigera. Xylanase activity was maximum (25.1 U/g) followed by pectinase (19.2 U/g) and cellulase (1.5 U/g), whereas, protease activity was unnoticed. There was significant correlation (P < 0.05) between disease rating scale and pectinase, xylanase and cellulase activity in infected tissues. This indicates the simultaneous production of hydrolytic enzymes that aids in necrosis of fruit tissues. The elevated levels of these enzymes in infected tissues as compared with control suggest their possible role in pathogenesis. Thus, pectinase, cellulase and xylanase produced by C. raphigera acts as major virulence factors in the development of fruit rot in pomegranates. This is a first report of fungal fruit rot caused by C. raphigera in pomegranate.

  4. Factors influencing behavior in the forced swim test.

    PubMed

    Bogdanova, Olena V; Kanekar, Shami; D'Anci, Kristen E; Renshaw, Perry F

    2013-06-13

    The forced swim test (FST) is a behavioral test in rodents which was developed in 1978 by Porsolt and colleagues as a model for predicting the clinical efficacy of antidepressant drugs. A modified version of the FST added the classification of active behaviors into swimming and climbing, in order to facilitate the differentiation between serotonergic and noradrenergic classes of antidepressant drugs. The FST is now widely used in basic research and the pharmaceutical screening of potential antidepressant treatments. It is also one of the most commonly used tests to assess depressive-like behavior in animal models. Despite the simplicity and sensitivity of the FST procedure, important differences even in baseline immobility rates have been reported between different groups, which complicate the comparison of results across studies. In spite of several methodological papers and reviews published on the FST, the need still exists for clarification of factors which can influence the procedure. While most recent reviews have focused on antidepressant effects observed with the FST, this one considers the methodological aspects of the procedure, aiming to summarize issues beyond antidepressant action in the FST. The previously published literature is analyzed for factors which are known to influence animal behavior in the FST. These include biological factors, such as strain, age, body weight, gender and individual differences between animals; influence of preconditioning before the FST: handling, social isolation or enriched environment, food manipulations, various kinds of stress, endocrine manipulations and surgery; schedule and routes of treatment, dosage and type of the drugs as well as experimental design and laboratory environmental effects. Consideration of these factors in planning experiments may result in more consistent FST results.

  5. Factors influencing the microbial safety of fresh produce: a review.

    PubMed

    Olaimat, Amin N; Holley, Richard A

    2012-10-01

    Increased consumption, larger scale production and more efficient distribution of fresh produce over the past two decades have contributed to an increase in the number of illness outbreaks caused by this commodity. Pathogen contamination of fresh produce may originate before or after harvest, but once contaminated produce is difficult to sanitize. The prospect that some pathogens invade the vascular system of plants and establish "sub-clinical" infection needs to be better understood to enable estimation of its influence upon risk of human illness. Conventional surface sanitation methods can reduce the microbial load, but cannot eliminate pathogens if present. Chlorine dioxide, electrolyzed water, UV light, cold atmospheric plasma, hydrogen peroxide, organic acids and acidified sodium chlorite show promise, but irradiation at 1 kGy in high oxygen atmospheres may prove to be the most effective means to assure elimination of both surface and internal contamination of produce by pathogens. Pathogens of greatest current concern are Salmonella (tomatoes, seed sprouts and spices) and Escherichia coli O157:H7 on leafy greens (spinach and lettuce). This review considers new information on illness outbreaks caused by produce, identifies factors which influence their frequency and size and examines intervention effectiveness. Research needed to increase our understanding of the factors influencing microbial safety of fresh produce is addressed.

  6. High Enrollment Course Success Factors in Virtual School: Factors Influencing Student Academic Achievement

    ERIC Educational Resources Information Center

    Liu, Feng; Cavanaugh, Cathy

    2011-01-01

    This paper describes a study of success factors in high enrollment courses in a K-12 virtual school learning environment. The influence of variables: time student spent in the learning management system (LMS), number of times logged into the LMS, teacher comment, participation in free or reduced lunch programs, student status in the virtual school…

  7. Microconical silicon structures influence NGF-induced PC12 cell morphology.

    PubMed

    Simitzi, C; Stratakis, E; Fotakis, C; Athanassakis, I; Ranella, A

    2015-04-01

    Micro-and nanofabrication techniques provide the opportunity to develop new types of cell culture platform, where the effect of various topographical cues on cellular functions such as proliferation and differentiation can be studied. In this study, PC12 cells were cultured on patterned silicon (Si) surfaces comprising arrays of microcones (MCs) exhibiting different geometrical characteristics and surface chemistries. It was illustrated that, in the absence of nerve growth factor (NGF), PC12 cells increased proliferation on all types of patterned surface, as compared to flat Si surfaces. However, in the presence of NGF, PC12 cells showed different responses, depending on the plating surface. Unlike low and intermediate rough MC surfaces, highly rough ones exhibiting large distances between MCs did not support PC12 cell differentiation, independently of the MCs' chemical coatings. These results suggest that the geometrical characteristics of MCs alone can influence specific cellular functions. Tailoring of the physical properties of arrays of Si MCs in order to identify which combinations of MC topologies and spatially defined chemistries are capable of driving specific cellular responses is envisaged.

  8. The influence of bony morphology on the magnitude of the pivot shift.

    PubMed

    Musahl, Volker; Ayeni, Olufemi R; Citak, Musa; Irrgang, James J; Pearle, Andrew D; Wickiewicz, Thomas L

    2010-09-01

    The purpose of this study was to correlate clinical pivot shift grading with femoral condyle size as measured on pre-operative magnet resonance imaging (MRI) of patients with anterior cruciate ligament (ACL) injury. Forty-nine consecutive patients for anterior cruciate ligament (ACL) surgery were examined under anesthesia. The pivot shift was graded according to Galway et al. and MacIntosh et al. by a single observer. The grade of pivot shift, Lachman, and collateral laxity was recorded. Intraoperative findings of injury patterns to the ACL and other soft tissue structures were recorded. The anterior-posterior (AP) and medial-lateral (ML) diameter of femoral condyles and tibial plateaus were measured on pre-operative MRI. Patients were grouped into a grade 1 pivot shift group and a grade 2 pivot shift group. ANOVA and independent t tests were used to compare bony dimensions between grade 1 and 2 pivot shifts and by sex. Significance was set at P < 0.05. Twenty-seven patients had a grade 1 pivot shift and 22 a grade 2 pivot shift. Associated pathology was present in 11/27 patients (41%) with a grade 1 pivot shift and 21/22 patients (95%) with a grade 2 pivot shift. The ML diameter of the lateral tibial plateau was significantly smaller in patients with a grade 2 pivot shift (35.5 +/- 3.7 mm) compared to patients with a grade 1 pivot shift (30.3 +/- 3.2 mm; P < 0.05). No difference was detected for any of the other measurements taken (NS). When analyzed by sex this difference existed in women (group I: 31.1 +/- 3.2, group II: 28.8 +/- 2.0; P < 0.05) but not in men (group I: 34.1 +/- 3.7, group II: 33.1 +/- 3.1; NS). All morphologic measurements were larger in men (P < 0.05). A smaller (ML) lateral tibial plateau diameter may contribute to a patient's higher-grade pivot shift. When analyzed by sex this was true for women but not for men. There are other factors contributing to the magnitude of the pivot shift, such as concomitant generalized laxity, injury to the knee

  9. Influence of fossoriality on inner ear morphology: insights from caecilian amphibians.

    PubMed

    Maddin, Hillary C; Sherratt, Emma

    2014-07-01

    It is widely accepted that a relationship exists between inner ear morphology and functional aspects of an animal's biology, such as locomotor behaviour. Animals that engage in agile and spatially complex behaviours possess semicircular canals that morphologically maximise sensitivity to correspondingly complex physical stimuli. Stemming from the prediction that fossorial tetrapods require a well-developed sense of spatial awareness, we investigate the hypothesis that fossoriality leads to inner ear morphology that is convergent with other spatially adept tetrapods. We apply morphometrics to otic capsule endocasts of 26 caecilian species to quantify aspects of inner ear shape, and compare these with a sample of frog and salamander species. Our results reveal caecilians (and also frogs) possess strongly curved canals, a feature in common with spatially adept species. However, significantly shorter canals in caecilians suggest reduced sensitivity, possibly associated with reduced reliance on vestibulo-ocular reflexes in this group of visually degenerate tetrapods. An elaboration of the sacculus of caecilians is interpreted as a unique adaptation among amphibians to increase sensitivity to substrate-borne vibrations transmitted through the head. This study represents the first quantitative analyses of inner ear morphology of limbless fossorial tetrapods, and identifies features within a new behavioural context that will contribute to our understanding of the biological consequences of physical stimuli on sensory function and associated morphological evolution.

  10. Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

    PubMed Central

    Tapia, Javier E.; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A.

    2016-01-01

    Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae–microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga. PMID:26941722

  11. A Broad Set of Chromatin Factors Influences Splicing

    PubMed Central

    Allemand, Eric; Myers, Michael P.; Garcia-Bernardo, Jose; Harel-Bellan, Annick; Krainer, Adrian R.; Muchardt, Christian

    2016-01-01

    Several studies propose an influence of chromatin on pre-mRNA splicing, but it is still unclear how widespread and how direct this phenomenon is. We find here that when assembled in vivo, the U2 snRNP co-purifies with a subset of chromatin-proteins, including histones and remodeling complexes like SWI/SNF. Yet, an unbiased RNAi screen revealed that the outcome of splicing is influenced by a much larger variety of chromatin factors not all associating with the spliceosome. The availability of this broad range of chromatin factors impacting splicing further unveiled their very context specific effect, resulting in either inclusion or skipping, depending on the exon under scrutiny. Finally, a direct assessment of the impact of chromatin on splicing using an in vitro co-transcriptional splicing assay with pre-mRNAs transcribed from a nucleosomal template, demonstrated that chromatin impacts nascent pre-mRNP in their competence for splicing. Altogether, our data show that numerous chromatin factors associated or not with the spliceosome can affect the outcome of splicing, possibly as a function of the local chromatin environment that by default interferes with the efficiency of splicing. PMID:27662573

  12. Influencing factors of mental health of medical students in China.

    PubMed

    Yang, Fan; Meng, Heng; Chen, Hui; Xu, Xin-hao; Liu, Zhuo; Luo, Ai; Feng, Zhan-chun

    2014-06-01

    This study investigated the mental health status of medical students in China, and analyzed the influencing factors in order to provide evidence for mental health education for medical students. A stratified cluster sampling method was used to recruit medical students from Huazhong University of Science and Technology, China. The questionnaire survey on general information and Symptom Checklist 90 (SCL-90) were used for investigation and analysis. The results showed among the 1137 valid questionnaires, 278 (24.45%) participants had SCL-90 score ≥ 160. The top three mental problems of medical students were obsessive-compulsive disorder, interpersonal sensitivity and depression in terms of the factor score ≥ 2.5 and the number of participants who reflected on the diseases. The third-year medical students had the worst mental health status, and fifth-year medical students had the best mental health status. Students from rural area had more psychological problems than those from urban area; furthermore, students with high professional satisfaction, those who were the single child of the family, non-poor students, and those whose parents had high education level had better mental health status. It was concluded that the mental health of medical students is not optimistic in China. Medical students have some mental health problems of different degrees. Factors that influence the mental health of medical students include academic pressure, professional satisfaction level and family environment.

  13. Expecting success: Factors influencing ninth graders' science self-efficacy

    NASA Astrophysics Data System (ADS)

    Donahue, Elizabeth

    What factors influence ninth grade students' expectations for success in science? Using social cognitive theory and bioecological systems theory as theoretical frameworks, this dissertation employs data from the High School Longitudinal Study of 2009 (HSLS:09) to examine the relative impact of teacher practices and their perceived attitudes on students' science self-efficacy. Further, as they relate to this broader issue, the relative impact of student subjective task value and teacher characteristics is also investigated. It has been well documented that U.S. students are not achieving at satisfactory levels in science. Education policy has focused on improving science teacher quality as one way to address this problem. Teacher effectiveness has been primarily measured by student achievement on standardized tests. However, not enough attention has been given to the social cognitive factors that can lead to increased achievement and persistence in science as well as how teachers may influence these factors. This study interrogates the relationship between student and teacher variables and the social cognitive construct of self-efficacy, which has proven to have a significant impact on student achievement and persistence in science. Findings add to the current literature surrounding ways that educators may increase student performance in science by employing policies and practices that benefit the development of student science self-efficacy.

  14. Influence of surfactants on the morphology of SnO{sub 2} nanocrystals prepared via a hydrothermal method

    SciTech Connect

    Wang Mi; Gao Yanfeng; Dai Lei; Cao Chuanxiang; Guo Xuhong

    2012-05-15

    Nanoscaled SnO{sub 2} with different morphologies has been synthesized via a simple hydrothermal process at 180 Degree-Sign C using polyvinylpyrrolidone (PVP), sodium dodecyl sulfonate (SDS), cetyl trimethyl ammonium bromide (CTAB) or tetrapropyl ammonium bromide (TPAB) as surfactant. All the prepared SnO{sub 2} are of a tetragonal crystal structure. Nanocubes, nanorods, nanosheets, nanobelts and nanoparticles were prepared when changing the type and dosage of organic surfactants. It is shown that anionic surfactant (SDS) and cationic surfactant (CTAB or TPAB) at their suitable addition amounts can largely influence the morphologies of SnO{sub 2} nanocrystals. The effect is significantly dependent on the solvent types: water or ethanol. The non-ionic surfactant (PVP) can also change the morphologies like SDS but the impacts are less obvious. The effect of surfactants on the shape and size of SnO{sub 2} nanoparticles was discussed in detail. The particle growth mechanism is described based on the electrostatic interactions and Van der Waals' forces. - Graphical abstract: SnO{sub 2} nanocrystals with controllable morphologies were prepared via a hydrothermal method with surfactants. Highlights: Black-Right-Pointing-Pointer SnO{sub 2} nanocrystals were prepared via a hydrothermal method with surfactants. Black-Right-Pointing-Pointer SnO{sub 2} morphologies changed with the type and the dosage of surfactants. Black-Right-Pointing-Pointer The effect of surfactants on the growth of crystal planes was studied. Black-Right-Pointing-Pointer The controlling mechanisms of surfactants on SnO{sub 2} morphologies were discussed.

  15. Factors influencing choice of dental treatment by private general practitioners.

    PubMed

    Brennan, David S; Spencer, A John

    2002-01-01

    Service rate variations have focused attention on treatment decisions. The aims of this study were to examine factors considered in choosing treatments, to classify dentists in terms of clinical decision making, and to investigate the association of decision making with services provided. From a random sample of dentists (response rate 60.3%) treatment constraints (15.0%), periodontal status (12.1%), tooth status (11.3%), mouth status (10.1%), and patient factors (9.8%) were considered important factors across six alternative treatment pair choice scenarios. Cluster analysis of the treatment choice scenarios produced one cluster that reflected patient preferences, another that reflected treatment constraints such as cost, and a third that reflected oral health factors. Compared with the oral health cluster, dentists in the constraints cluster had higher rates (p < .05) of extractions (rate ratio [RR] = 1.49), bridge work (RR = 1.77), and dentures (RR = 1.32), whereas dentists in the patient cluster had higher restoration rates for two-surface ionomers (RR = 2.45) and resins on three or more surfaces (RR = 1.50) and other preventive services (RR = 1.78) such as oral hygiene instruction. Although a range of factors influenced treatment choice, a limited set accounted for the majority of responses, with cost a major determinant, ahead of oral health status and patient preference. Decision-making style was associated with service provision.

  16. Neutralising fair credit: factors that influence unethical authorship practices.

    PubMed

    Trinkle, Brad S; Phillips, Trisha; Hall, Alicia; Moffatt, Barton

    2017-01-31

    This study experimentally tests whether the techniques of neutralisation as identified in the criminal justice literature influence graduate student willingness to engage in questionable research practices (QRPs). Our results indicate that US-born graduate students are more willing to add an undeserved coauthor if the person who requests it is a faculty member in the student's department as opposed to a fellow student. Students are most likely to add an undeserving author if a faculty member is also their advisor. In addition, four techniques of neutralisation, 'diffusion of responsibility', 'defence of necessity', 'advantageous comparison' and 'euphemistic labelling', are associated with student willingness to act unethically. Participants who had received responsible conduct of research training were no less likely to commit the violation than those who had not. Knowledge of these influencing factors for QRPs will provide for opportunities to improve research ethics education strategies and materials.

  17. Psychosocial factors influencing breast cancer risk appraisal among older women.

    PubMed

    Wood, Robin Y; Della-Monica, Nola R

    2011-06-01

    Although the incidence of breast cancer increases with age, many older women are uninformed about the increased risk and have lower mammography screening rates than younger women. Understanding older women's perceptions of risk might assist health care providers in offering appropriate resources that result in screening. In this study, we explored psychosocial components influencing older women's breast cancer risk appraisal. To identify key psychosocial components of breast cancer risk appraisal, we conducted focus group interviews. Data saturation occurred with four groups (N = 36) of older Black (58%) and White (42%) women with no prior history of breast cancer. On analysis of the data, we found three themes representing psychosocial factors influencing breast cancer risk appraisal with this cohort. Our findings revealed that worry/fear/anxiety, self-regulating empowerment, and realistic optimism were psychosocial mechanisms older Black and White women in this sample used in appraising breast cancer risk.

  18. Factors influencing dissipation of avermectins in sheep faeces.

    PubMed

    Virant Celestina, Tina; Kolar, Lucija; Gobec, Ivan; Kuzner, Jernej; Flajs, Vesna Cerkvenik; Pogacnik, Milan; Erzen, Nevenka Kozuh

    2010-01-01

    Factors influencing fate of avermectins (abamectin, doramectin) in faeces of treated sheep were investigated under different experimental conditions. In the laboratory, concentrations of both avermectins were declined in homogenised faeces of treated animals until day 14 of exposure, regardless of experimental conditions. After that day, no significant decrease in concentrations was observed till the end of the experiment. Established DT(50) did not exceed 9 days. In the karst pasture, an average DT(50) of 27 days was established for abamectin and 23 days for doramectin in natural faeces of treated sheep. In the compost mixture, doramectin concentration was decreased by 38.9+/-2.6% during 21 days of the thermophilic phase of composting. Therefore, DT(50) was not established. A possible influence of moisture content of sheep faeces on concentrations of avermectins was observed.

  19. Influence of Si ion implantation on structure and morphology of g-C3N4

    NASA Astrophysics Data System (ADS)

    Varalakshmi, B.; Sreenivasulu, K. V.; Asokan, K.; Srikanth, V. V. S. S.

    2016-07-01

    Effect of Si ion implantation on structural and morphological features of graphite-like carbon nitride (g-C3N4) was investigated. g-C3N4 was prepared by using a simple atmospheric thermal decomposition process. The g-C3N4 pellets were irradiated with a Si ion beam of energy 200 keV with different fluencies. Structural, morphological and elemental, and phase analysis of the implanted samples in comparison with the pristine samples was carried out by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) techniques, respectively. The observations revealed that Si ion implantation results in a negligible change in the crystallite size and alteration of the network-like to the sheet-like morphology of g-C3N4 and Si ions in the g-C3N4 network.

  20. Removal of heavy metal ions by biogenic hydroxyapatite: Morphology influence and mechanism study

    NASA Astrophysics Data System (ADS)

    Wang, Dandan; Guan, Xiaomei; Huang, Fangzhi; Li, Shikuo; Shen, Yuhua; Chen, Jun; Long, Haibo

    2016-08-01

    Based on the synthesis of hydroxyapatite (HA) with different morphologies, such as nanorod-like, flower-like and sphere-like assembled HA nanorods, a new strategy has been developed for the removal of heavy metal ions such as Pb2+, Cu2+, Mn2+, Zn2+. The dependence of removal efficiency on the morphology and the suspended concentration of trapping agent, the removal time and selectivity were evaluated and discussed. The experimental results proved that the removal capacity of flower-like assembled HA nanorods (NAFL-HA) was the best, and the maximum removal ratio for Pb2+ ion was 99.97%. The mechanism of Pb2+ removal was studied in detail, noting that some metal ions were completely incorporated into hydroxyapatitie to produce Pb-HA. It reveals that the metal ions capture by HA is mainly controlled by sample surface adsorption and co-precipitation, which are directly controlled by sample morphology.

  1. Influence of Growth Time and Temperature on the Morphology of ZnO Nanorods via Hydrothermal

    NASA Astrophysics Data System (ADS)

    Shaziman, Syahirah; Syakirin Ismail@rosdi, Ahmad; Hafiz Mamat, Mohamad; Sabirin Zoolfakar, Ahmad

    2015-11-01

    This research investigates the effect of temperature and growth duration on the morphology of ZnO. ZnO nanostructure can be synthesized via hydrothermal method using Zinc Acetate and hexamethylenetetramine (HMT) as precursor and glass slide as a substrate. The temperature and growth time vary from 50-95 °C and 50-100 minutes, respectively. The substrates with ZnO nanostructures are annealed at different temperatures which are 200°C and 500°C. The result indicates that different temperature and growth time produces different morphologies in size. Thus, the morphology of ZnO nanostructure affects by the parameters such as temperature and growth time via hydrothermal grown.

  2. Factors influencing stakeholders attitudes toward genetically modified aedes mosquito.

    PubMed

    Amin, Latifah; Hashim, Hasrizul

    2015-06-01

    Dengue fever is a debilitating and infectious disease that could be life-threatening. It is caused by the dengue virus which affects millions of people in the tropical area. Currently, there is no cure for the disease as there is no vaccine available. Thus, prevention of the vector population using conventional methods is by far the main strategy but has been found ineffective. A genetically modified (GM) mosquito is among the favoured alternatives to curb dengue fever in Malaysia. Past studies have shown that development and diffusion of gene technology products depends heavily upon public acceptance. The purpose of this study is to identify the relevant factors influencing stakeholders' attitudes toward the GM Aedes mosquito and to analyse the relationships between all the factors using the structural equation model. A survey was carried out on 509 respondents from various stakeholder groups in the Klang Valley region of Malaysia. Results of the survey have confirmed that public perception towards complex issues such as gene technology should be seen as a multi-faceted process. The perceived benefit-perceived risk balance is very important in determining the most predominant predictor of attitudes toward a GM mosquito. In this study the stakeholders perceived the benefit of the GM mosquito as outweighing its risk, translating perceived benefit as the most important direct predictor of attitudes toward the GM mosquito. Trust in key players has a direct influence on attitudes toward the GM mosquito while moral concern exhibited an indirect influence through perceived benefits. Other factors such as attitudes toward technology and nature were also indirect predictors of attitudes toward the GM mosquito while religiosity and engagement did not exhibited any significant roles. The research findings serve as a useful database to understand public acceptance and the social construct of public attitudes towards the GM mosquito to combat dengue.

  3. Factors influencing trace element composition in human teeth

    SciTech Connect

    Tandon, L.; Iyengar, G.V.

    1997-12-01

    The authors recently compiled and reviewed the literature published in or after 1978 for 45 major, minor, and trace elements in human teeth as a part of an International Atomic Energy Agency (IAEA) study. The purpose of this paper is to discuss the various factors that influence the concentration levels of certain trace elements in human teeth. The sampling practices and analytical techniques that are applicable for trace element analysis are also discussed. It is also our intention to identify reference range of values, where data permit such conclusions. The scrutiny was designed to identify only the healthy permanent teeth, and values from teeth with fillings, caries, or periodontal diseases were eliminated.

  4. Influence of buffer composition on the distribution of inkjet printed protein molecules and the resulting spot morphology.

    PubMed

    Mujawar, Liyakat Hamid; van Amerongen, Aart; Norde, Willem

    2012-08-30

    Producing high quality protein microarrays on inexpensive substrates like polystyrene is a big challenge in the field of diagnostics. Using a non-contact inkjet printer we have produced microarrays on polystyrene slides for two different biotinylated biomolecules, bovine serum albumin (BSA-biotin) and immunoglobulin-G (IgG-biotin), and studied the influence of buffer (composition and pH) on the spot morphology and signal intensity. Atomic force microscopy revealed the morphological pattern of the (biomolecule) spots printed from phosphate buffer (pH 7.4), phosphate buffered saline (pH 7.4) and carbonate buffer (pH 9.6). The spots showed an irregular crust-like appearance when printed in phosphate buffered saline (pH 7.4), mainly due to the high NaCl content, whereas spots of biomolecules printed in carbonate buffer (pH 9.6) showed a smooth morphology. In addition, the rinsing of these dried spots led to the loss of a considerable fraction of the biomolecules, leaving behind a small fraction that is compatible with the (mono)layer. It was confirmed by confocal laser microscopy that the quality of the spots with respect to the uniformity and distribution of the biomolecules therein was superior when printed in carbonate buffer (pH 9.6) as compared to other buffer systems. Particularly, spotting in PBS yielded spots having a very irregular distribution and morphology.

  5. The influence of log jam development on channel morphology in an intermediate sized coastal stream, Carnation Creek, B.C.

    NASA Astrophysics Data System (ADS)

    Luzi, D. S.; Sidle, R. C.; Hogan, D. L.

    2006-12-01

    Large wood (LW) is an important functional and structural component of forest stream ecosystems, regulating sediment storage and transport, consequently determining channel morphology, and as an important foundation for aquatic habitat. LW occurs as either individual pieces or in accumulations (log jams). Where individual pieces of LW affect the stream at a small scale, several bankfull widths, jams influence the stream on a much larger scale. The spatial extent of jam related effects on channel morphology vary, dependent upon the life stage of the jam. Temporal changes in jams have received relatively little attention in the literature. The development stage of a jam is associated with upstream channel aggradation and downstream degradation; this process reverses during a jam's deterioration phase. Carnation Creek, an 11 km2 watershed located on the west coast of Vancouver Island, provided a rare opportunity to examine both the spatial and temporal impacts of log jams on channel morphology. An understanding of these relationships will be developed through the analysis of changes in channel variables, such as channel dimensions, pattern, hydraulic characteristics, and morphology. These characteristics will be extracted from annual cross sectional surveys taken during 1971 - 1998.

  6. Cadmium in rice: Transport mechanisms, influencing factors, and minimizing measures.

    PubMed

    Li, Hui; Luo, Na; Li, Yan Wen; Cai, Quan Ying; Li, Hui Yuan; Mo, Ce Hui; Wong, Ming Hung

    2017-05-01

    Cadmium (Cd) accumulation in rice and its subsequent transfer to food chain is a major environmental issue worldwide. Understanding of Cd transport processes and its management aiming to reduce Cd uptake and accumulation in rice may help to improve rice growth and grain quality. Moreover, a thorough understanding of the factors influencing Cd accumulation will be helpful to derive efficient strategies to minimize Cd in rice. In this article, we reviewed Cd transport mechanisms in rice, the factors affecting Cd uptake (including physicochemical characters of soil and ecophysiological features of rice) and discussed efficient measures to immobilize Cd in soil and reduce Cd uptake by rice (including agronomic practices, bioremediation and molecular biology techniques). These findings will contribute to ensuring food safety, and reducing Cd risk on human beings.

  7. Factors Influencing Dating Experiences Among African American Emerging Adults

    PubMed Central

    Hall, Naomi M.; Lee, Anna K.; Witherspoon, Daphne D.

    2014-01-01

    This study examined sociocultural factors that impact dating and sexual experiences of heterosexual African American undergraduate college students attending a historically Black institution in the Southeastern United States. Specifically, mate availability and relationship involvement were analyzed to document students’ experiences, and how these influences may be associated with sexual decision making and behavior. Data from nine focus groups (N = 57) were aggregated and four subthemes were identified: competition among women, acceptability of mates, high prevalence of casual relationships, and lowered expectations for commitment. Power dynamics emerged as a contributing factor to the types of relationship involvement, sexual decision-making, and behavior among participants. The importance of prevention programs focusing on situational and cultural variables is highlighted. Additionally, implications for professionals working with emerging adults to consider the impact of the gender ratio imbalance, and perceived power distributions on perceptions of dating relationships, and sexual decision making and behavior are addressed. PMID:25530924

  8. Astrocyte morphology after ischemic and hemorrhagic experimental stroke has no influence on the different recovery patterns.

    PubMed

    Mestriner, Régis Gemerasca; Saur, Lisiani; Bagatini, Pamela Brambilla; Baptista, Pedro Porto Alegre; Vaz, Sabrina Pereira; Ferreira, Kelly; Machado, Susane Alves; Xavier, Léder Leal; Netto, Carlos Alexandre

    2015-02-01

    Stroke, broadly subdivided into ischemic and hemorrhagic subtypes, is a serious health-care problem worldwide. Previous studies have suggested ischemic and hemorrhagic stroke could present different functional recovery patterns. However, little attention has been given to this neurobiological finding. Coincidently, astrocyte morphology could be related to improved sensorimotor recovery after skilled reaching training and modulated by physical exercise and environmental enrichment. Therefore, it is possible that astrocyte morphology might be linked to differential recovery patterns between ischemic and hemorrhagic stroke. Thus, we decided to compare long-term GFAP-positive astrocyte morphology after ischemic (IS, n=5), hemorrhagic (HS, n=5) and sham (S, n=5) stroke groups (induced by endothelin-1, collagenase type IV-S and salina, respectively). Our results showed ischemic and hemorrhagic stroke subtypes induced similar long-term GFAP-positive astrocyte plasticity (P>0.05) for all evaluated measures (regional and cellular optical density; astrocytic primary processes ramification and length; density of GFAP positive astrocytes) in perilesional sensorimotor cortex and striatum. These interesting negative results discourage similar studies focused on long-term plasticity of GFAP-positive astrocyte morphology and recovery comparison of stroke subtypes.

  9. Influence of nitrogen and phosphorous on the growth and root morphology of Acer mono

    PubMed Central

    Zhang, Peng; Shen, Hai-long; Salahuddin

    2017-01-01

    Nitrogen and phosphorous are critical determinants of plant growth and productivity, and both plant growth and root morphology are important parameters for evaluating the effects of supplied nutrients. Previous work has shown that the growth of Acer mono seedlings is retarded under nursery conditions; we applied different levels of N (0, 5, 10, and 15 g plant-1) and P (0, 4, 6 and 8 g plant-1) fertilizer to investigate the effects of fertilization on the growth and root morphology of four-year-old seedlings in the field. Our results indicated that both N and P application significantly affected plant height, root collar diameter, chlorophyll content, and root morphology. Among the nutrient levels, 10 g N and 8 g P were found to yield maximum growth, and the maximum values of plant height, root collar diameter, chlorophyll content, and root morphology were obtained when 10 g N and 8 g P were used together. Therefore, the present study demonstrates that optimum levels of N and P can be used to improve seedling health and growth during the nursery period. PMID:28234921

  10. Environment and gut morphology influence microplastic retention in langoustine, Nephrops norvegicus.

    PubMed

    Welden, Natalie A C; Cowie, Phillip R

    2016-07-01

    Over the past twenty years microplastic pollution has been recorded in all major marine habitats, and is now considered to be of high environmental concern. Correspondingly, the number of reports of microplastic ingestion by marine species is increasing. Despite this, there are still relatively few studies which address the uptake and retention of microplastic in wild populations. Langoustine, Nephrops norvegicus, sampled from the Clyde Sea Area, have previously been seen to contain large aggregations of microplastic fibres. The large proportion of contaminated individuals and size of the microplastic aggregations observed suggests that Nephrops are at high risk of microplastic ingestion. In this study the levels of ingested microplastic in populations of N. norvegicus from the Clyde Sea Area, North Minch and North Sea are examined. Animals in the near-shore, Clyde Sea population showed both a higher percentage of microplastic containing individuals and much greater weights of microplastic retained in the gut. N. norvegicus revealed that only a small percentage of individuals from the North Sea and Minch contained microplastic, predominantly single strands. An expanded sample from the Clyde Sea Area was examined to identify the factors influencing microplastic retention. This revealed that males, larger individuals, and animals that had recently moulted contained lower levels of microplastic. The presence of identified food items in the gut was not seen to correlate with microplastic loads. Observations of microplastic in the shed stomach lining of recently moulted individuals and the lack of aggregations in wild-caught individuals suggests that ecdysis is the primary route of microplastic loss by N. norvegicus. Therefore the large aggregations observed in wild-caught animals are believed to build up over extended periods as a result of the complex gut structure of N. norvegicus.

  11. Postnatal treatment factors affecting craniofacial morphology of unilateral cleft lip and palate (UCLP) patients in a Japanese population.

    PubMed

    Alam, M K; Iida, J; Sato, Y; Kajii, Takashi S

    2013-12-01

    We have evaluated the craniofacial morphology of Japanese patients with unilateral cleft lip and palate (UCLP) and assessed the various postnatal factors that affect it. Lateral cephalograms of 140 subjects (mean (SD) aged 7 (2) years) with UCLP were taken before orthodontic treatment. Surgeons from Hokkaido University Hospital had done the primary operations. The craniofacial morphology was assessed by angular and linear cephalometric measurements. Cheiloplasty, palatoplasty, and preoperative orthopaedic treatment were chosen as postnatal factors. To compare the assessments of the postnatal factors, we made angular and linear cephalometric measurements for each subject and converted them into Z scores in relation to the mean (SD) of the two variables. Subjects treated by the modified Millard cheiloplasty had larger sella-nasion-point A (SNA) and nasion-point A-pogonion (NA-POG) measurements than subjects treated by the modified Millard with a vomer flap cheiloplasty. Two-stage palatoplasty showed consistently better craniofacial morphology than the other palatoplasty. Subjects who had preoperative orthopaedic treatment with a Hotz plate had significantly larger upper incisor/sella-nasion (U1-SN) measurements than who had no preoperative orthopaedic treatment or an active plate. We conclude that in subjects treated by a modified Millard type of cheiloplasty, a two-stage palatoplasty, and a Hotz plate there were fewer adverse effects on craniofacial morphology.

  12. Factors That Influence the Extensional Rheological Property of Saliva

    PubMed Central

    Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy

    2015-01-01

    The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva. PMID:26305698

  13. Factors That Influence the Extensional Rheological Property of Saliva.

    PubMed

    Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy

    2015-01-01

    The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva.

  14. The extracellular adherence protein (Eap) of Staphylococcus aureus acts as a proliferation and migration repressing factor that alters the cell morphology of keratinocytes.

    PubMed

    Eisenbeis, Janina; Peisker, Henrik; Backes, Christian S; Bur, Stephanie; Hölters, Sebastian; Thewes, Nicolas; Greiner, Markus; Junker, Christian; Schwarz, Eva C; Hoth, Markus; Junker, Kerstin; Preissner, Klaus T; Jacobs, Karin; Herrmann, Mathias; Bischoff, Markus

    2017-02-01

    Staphyloccocus aureus is a major human pathogen and a common cause for superficial and deep seated wound infections. The pathogen is equipped with a large arsenal of virulence factors, which facilitate attachment to various eukaryotic cell structures and modulate the host immune response. One of these factors is the extracellular adherence protein Eap, a member of the "secretable expanded repertoire adhesive molecules" (SERAM) protein family that possesses adhesive and immune modulatory properties. The secreted protein was previously shown to impair wound healing by interfering with host defense and neovascularization. However, its impact on keratinocyte proliferation and migration, two major steps in the re-epithelialization process of wounds, is not known. Here, we report that Eap affects the proliferation and migration capacities of keratinocytes by altering their morphology and adhesive properties. In particular, treatment of non-confluent HaCaT cell cultures with Eap resulted in cell morphology changes as well as a significant reduction in cell proliferation and migration. Eap-treated HaCaT cells changed their appearance from an oblong via a trapezoid to an astral-like shape, accompanied by decreases in cell volume and cell stiffness, and exhibited significantly increased cell adhesion. Eap had a similar influence on endothelial and cancer cells, indicative for a general effect of Eap on eukaryotic cell morphology and functions. Specifically, Eap was found to interfere with growth factor-stimulated activation of the mitogen-activated protein kinase (MAPK) pathway that is known to be responsible for cell shape modulation, induction of proliferation and migration of epithelial cells. Western blot analyses revealed that Eap blocked the phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2) in keratinocyte growth factor (KGF)-stimulated HaCaT cells. Together, these data add another antagonistic mechanism of Eap in wound healing, whereby the

  15. Numerical study on the standing morphology of an oblique detonation wave under the influence of an incoming boundary layer

    NASA Astrophysics Data System (ADS)

    Zhou, Jin; Liu, Yu; Lin, Zhi-yong

    2015-01-01

    The influence of an incoming boundary layer to the standing morphology of an oblique detonation wave (ODW) induced by a compression ramp is numerically studied in this paper. The Spalart-Allmaras (SA) turbulence model is used to perform simulation of detonationboundary- layer interactions. Three different wall conditions are applied to realize control on the boundary-layer separation scales. Accordingly, different standing morphologies of the ODWs are obtained, including smooth ODW (without transverse wave) under no-slip, adiabatic wall condition with large-scale separation, abrupt ODW (with transverse wave) under no-slip, cold wall condition with moderate-scale separation, and bow-shaped detached ODW under slipwall condition without a boundary layer.

  16. Identification of the influencing factors on groundwater drought in Bangladesh

    NASA Astrophysics Data System (ADS)

    Touhidul Mustafa, Syed Md.; Huysmans, Marijke

    2015-04-01

    Groundwater drought is a specific type of drought that concerns groundwater bodies. It may have a significant adverse effect on the socio-economic, agricultural, and environmental conditions. Investigating the effect of response different climatic and manmade factors on groundwater drought provides essential information for sustainable planning and management of water resources. The aim of this study is to identify the influencing factors on groundwater drought in a drought prone region in Bangladesh to understand the forcing mechanisms. The Standardised Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) have been used to quantify the aggregated deficit between precipitation and the evaporative demand of the atmosphere. The influence of land use patterns on the groundwater drought has been identified by calculating spatially distributed groundwater recharge as a function of land use. The result shows that drought intensity is more severe during the dry season (November to April) compared to the rainy season (May to October). The evapotranspiration and rainfall deficit has a significant effect on meteorological drought which has a direct relation with groundwater drought. Urbanization results in a decrease of groundwater recharge which increases groundwater drought severity. Overexploitation of groundwater for irrigation and recurrent meteorological droughts are the main causes of groundwater drought in the study area. Efficient irrigation management is essential to reduce the growing pressure on groundwater resources and ensure sustainable water management. More detailed studies on climate change and land use change effects on groundwater drought are recommended. Keywords: Groundwater drought, SPI & RDI, Spatially distributed groundwater recharge, Irrigation, Bangladesh

  17. Factors influencing quality of chest compression depth in nursing students.

    PubMed

    Roh, Young Sook; Lim, Eun Ju

    2013-12-01

    The purpose of the study was to identify factors influencing quality of chest compression depth in nursing students. A convenience sample of 102 female nursing students enrolled in a cardiopulmonary resuscitation skills training session. Each student performed 3 min of chest compression skills on a Resusci Anne SkillReporter manikin for measurements of both depth and rate. Nursing students with correct compression depth (50-60 mm) had higher body weight (t = -2.02, P = 0.046) and body mass index (t = -2.19, P = 0.031) compared with students in the incorrect depth group. Mean chest compression depth was shallower in underweight nursing students compared with normal weight or overweight students (F = 8.89, P < 0.001). Body weight was a significant factor influencing quality of chest compression depth (F = 4.25, P = 0.003). Educational intervention targeting underweight nursing students might need to enhance the quality of chest compression skills.

  18. Multiple Factors Influence Glomerular Albumin Permeability in Rats

    PubMed Central

    Sandoval, Ruben M.; Wagner, Mark C.; Patel, Monica; Campos-Bilderback, Silvia B.; Rhodes, George J.; Wang, Exing; Wean, Sarah E.; Clendenon, Sherry S.

    2012-01-01

    Different laboratories recently reported incongruous results describing the quantification of albumin filtration using two-photon microscopy. We investigated the factors that influence the glomerular sieving coefficient for albumin (GSCA) in an effort to explain these discordant reports and to develop standard operating procedures for determining GSCA. Multiple factors influenced GSCA, including the kidney depth of image acquisition (10–20 μm was appropriate), the selection of fluorophore (probes emitting longer wavelengths were superior), the selection of plasma regions for fluorescence measurements, the size and molecular dispersion characteristics of dextran polymers if used, dietary status, and the genetic strain of rat. Fasting reduced the GSCA in Simonsen Munich Wistar rats from 0.035±0.005 to 0.016±0.004 (P<0.01). Frömter Munich Wistar rats had a much lower GSCA in both the fed and the fasted states. Finally, we documented extensive albumin transcytosis with vesicular and tubular delivery to and fusion with the basolateral membrane in S1 proximal tubule cells. In summary, these results help explain the previously conflicting microscopy and micropuncture data describing albumin filtration and highlight the dynamic nature of glomerular albumin permeability. PMID:22223875

  19. Environmental Factors Influencing Arctic Halogen Chemistry During Late Spring

    NASA Astrophysics Data System (ADS)

    Burd, J.; Nghiem, S. V.; Simpson, W. R.

    2015-12-01

    Reactive halogen radicals (e.g. Br, Cl atoms and their oxides, BrO, ClO) are important oxidizers in the troposphere that decrease atmospheric pollutants and deplete tropospheric ozone, affecting the abundance of other oxidizers such as the hydroxyl radical. During Arctic springtime, the heterogeneous chemical cycles (often called the "bromine explosion") produce high levels of bromine monoxide (BrO), through reactions on saline snow, ice, and/or aerosol surfaces. Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) measured BrO at Barrow, AK, from 2008-2009 and 2012-2015, as well at various locations above the frozen Arctic Ocean with O-Buoys in 2008 and 2011-2015. Observed BrO levels drop suddenly during late spring (May-June) and generally do not recover, which indicates the bromine explosion cycle can no longer produce significant amounts of BrO. We have established, through an objective algorithm, the local day of year of this drop in BrO as the "seasonal end." Additionally, in about half of the years, "recurrence" events were observed where BrO levels recover for at least a day. This study investigates the environmental factors influencing seasonal end and recurrence events including: temperature, relative humidity, precipitation and snowmelt. Analysis of BrO and air temperature revealed the temperature reaches 0°C within five days of the seasonal end event; however, temperatures drop below freezing during a recurrence event. In addition, there are periods where the temperature remains below freezing, but no recurrence event is observed. This BrO and temperature analysis indicates above-freezing air temperature prevents reactive bromine release; however, it is not the only environmental factor influencing this heterogeneous recycling. Further analysis of additional environmental influences on the bromine explosion cycle could help to better understand and model bromine chemistry in the Arctic.

  20. Influence of implant shape, surface morphology, surgical technique and bone quality on the primary stability of dental implants.

    PubMed

    Elias, Carlos Nelson; Rocha, Felipe Assis; Nascimento, Ana Lucia; Coelho, Paulo Guilherme

    2012-12-01

    The primary stability of dental implants has been investigated before, but a study of the influence of implant shape, size and surface morphology (machined, acid etched or anodized), surgical technique (press-fit or undersized) and substrate (natural or simulated bone) on the primary stability of dental implants has not been reported. The present work intends to fill this gap. In this work, six different dental implants were inserted into and removed from synthetic and natural bone while measuring the torque. A total of 255 dental implants with three shapes, four sizes and three surface topographies were inserted into pig rib, PTFE and polyurethane. The implant sites were prepared using straight and tapered drills. The primary stability was estimated from the maximum insertion torque. Comparisons between samples were based on the maximum insertion torque (MIT), the maximum removal torque (MRT) and the torque ratio (TR=MRT/MIT). The insertion torque into pig ribs showed larger dispersion. All parameters (shape, size and surface morphology of the implant, surgical technique and substrate type) were found to have a significant influence on primary stability. The insertion of a tapered implant requires a higher torque than the insertion of a straight implant. Surface treatments improve the primary stability. The influence of the surgical technique is smaller than that of implant size and shape. The highest insertion torque was that of anodized tapered implants inserted into undersized sites. Finally, the primary stability of dental implants is highly dependent on implant design, surgical technique and substrate type.

  1. Morphological influence of TiO2 nanostructures (nanozigzag, nanohelics and nanorod) on photocatalytic degradation of organic dyes

    NASA Astrophysics Data System (ADS)

    Khan, Sadaf Bashir; Hou, Mengjing; Shuang, Shuang; Zhang, Zhengjun

    2017-04-01

    Hierarchical nanostructures have drawn significant attention and incredible performance in photodriven chemical conversion area due to its unique physicochemical properties. Herein, we study the morphological influence of TiO2 nanostructures on photocatalytic degradation of different organic dyes methyl blue, methyl violet and methyl orange present in industrial wastewater. Nanorod, nanohelics and nanozigzag TiO2 nanofilms were fabricated by using galancing angle deposition technique (GLAD). TiO2 nanofilms were characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and raman analysis. BET surface area analysis were carried out by using nitrogen adsorption desorption curves. The results show that TiO2 morphology had great influence on photocatalytic degradation of organic dyes due to difference in specific surface area and pore volume of nanostructures. The photocatalytic degradation experiments were carried out for three hours under UV-vis light irradiation. Catalysis recycling and organic dyes concentration influence were also studied. In case of high concentration of organic dyes, negligible degradation rate is observed. TiO2 nanozigzag films show better degradation performance than nanohelics and nanorod due to presence of large surface area for reaction, higher porosity with dispersion of active sites at different length scales of pores and presence of oxygen vacancies.

  2. Diverse influences of dietary factors on cancer in Asia.

    PubMed

    Moore, Malcolm A

    2009-01-01

    The major environmental risk factors for cancer are carcinogen and co-carcinogen exposure in tobacco, insufficient exercise and above all an unhealthy diet. What we eat or do not eat is exceedingly important in determining what cancers or other chronic disease we may suffer from. Carcinogens may be integral contaminants of the diet, like nitrosamines in some situations and aflatoxins, or may be generated by cooking processes, as is known to be the case for heterocyclic amine pyrolysis products. Examples of co-carcinogenic agents may include grit in bread products, salt in pickles or betel in chewing quids. Dietary insufficiencies, for example of zinc, may also act to increase sensitivity to genetic damage, for example. Influence on metabolism of carcinogens, like induction of phase II enzymes like glutathione S transferases, further directly impacts on carcinogenicity. Antioxidants in fruits and vegetables are typical examples of protective agents acting in this way. In addition we have dietary fibre which can decrease carcinogen exposure through accelerating passage of faeces through the gut. Other types of fibre, the soluble forms, can act to decrease uptake of glucose and thus suppress insulin exposure, an important factor for colon cancer. Natural anti-inflammatory agents like N-3 fatty acids in fish offer another example of preventive factors in the diet. Individual dietary components, like isoflavones in soy products, can interfere with hormone function to exert a beneficial action, as on the breast. Other compounds may act via stimulation of the immune system like lactoferrin and betaglucans. Perhaps the most important influence of diet on cancer, however, in a world of increasing comfort and ease of access to foodstuffs, is through over-eating and consequent obesity. Given the importance of diet to all our lives, we need to focus on all possible interactive effects in providing an evidence base to guide our choices regarding what we should eat in Asia.

  3. Evaporation of drops on two parallel fibers: influence of the liquid morphology and fiber elasticity.

    PubMed

    Duprat, Camille; Bick, Alison D; Warren, Patrick B; Stone, Howard A

    2013-06-25

    We investigate experimentally the evaporation of liquid accumulated on a pair of parallel fibers, rigid or flexible. The liquid wetting the fibers can adopt two distinct morphologies: a compact drop shape, whose evaporation dynamics is similar to that of an isolated aerosol droplet, or a long liquid column of constant cross-section, whose evaporation dynamics depends upon the aspect ratio of the column. We thus find that the evaporation rate is constant for drops, while it increases strongly for columns as the interfiber distance decreases, and we propose a model to explain this behavior. When the fibers are flexible, the transition from drops to columns can be induced by the deformation of the fibers because of the capillary forces applied by the drop. Thus, we find that the evaporation rate increases with increasing flexibility. Furthermore, complex morphology transitions occur upon drying, which results in spreading of the drop as it evaporates.

  4. Evolution of the brightest cluster galaxies: the influence of morphology, stellar mass and environment

    NASA Astrophysics Data System (ADS)

    Zhao, Dongyao; Aragón-Salamanca, Alfonso; Conselice, Christopher J.

    2015-11-01

    Using a sample of 425 nearby brightest cluster galaxies (BCGs) from von der Linden et al., we study the relationship between their internal properties (stellar masses, structural parameters and morphologies) and their environment. More massive BCGs tend to inhabit denser regions and more massive clusters than lower mass BCGs. Furthermore, cDs, which are BCGs with particularly extended envelopes, seem to prefer marginally denser regions and tend to be hosted by more massive haloes than elliptical BCGs. cD and elliptical BCGs show parallel positive correlations between their stellar masses and environmental densities. However, at a fixed environmental density, cDs are, on average, ˜40 per cent more massive. Our results, together with the findings of previous studies, suggest an evolutionary link between elliptical and cD BCGs. We suggest that most present-day cDs started their life as ellipticals, which subsequently grew in stellar mass and size due to mergers. In this process, the cD envelope developed. The large scatter in the stellar masses and sizes of the cDs reflects their different merger histories. The growth of the BCGs in mass and size seems to be linked to the hierarchical growth of the structures they inhabit: as the groups and clusters became denser and more massive, the BCGs at their centres also grew. This process is nearing completion since the majority (˜60 per cent) of the BCGs in the local Universe have cD morphology. However, the presence of galaxies with intermediate morphological classes (between ellipticals and cDs) suggests that the growth and morphological transformation of some BCGs is still ongoing.

  5. Morphology of carbonates particles precipitated from saline waste solution: Influence of magnesium

    NASA Astrophysics Data System (ADS)

    Filippov, L. O.; Grandjean, M.; Filippova, I. V.; Pelletier, M.

    2013-03-01

    The role of a very low concentration of Mg on the nature, morphology and surface of carbonate particles during soda-ash residual brine carbonation has been studied. The Mg concentration of 200 mg/kg in brine slows down the kinetic of carbonation, modifies the shape of precipitated particles and new carbonated phases are precipitated. The existence of aragonite and (Ca, Mg) hydrated phases is supposed for Ca:Mg ratio equivalent to 24:1 in solid fraction.

  6. Does aridity influence the morphology, distribution and accumulation of calcium oxalate crystals in Acacia (Leguminosae: Mimosoideae)?

    PubMed

    Brown, Sharon L; Warwick, Nigel W M; Prychid, Christina J

    2013-12-01

    Calcium oxalate (CaOx) crystals are a common natural feature of many plant families, including the Leguminosae. The functional role of crystals and the mechanisms that underlie their deposition remain largely unresolved. In several species, the seasonal deposition of crystals has been observed. To gain insight into the effects of rainfall on crystal formation, the morphology, distribution and accumulation of calcium oxalate crystals in phyllodes of the leguminous Acacia sect. Juliflorae (Benth.) C. Moore & Betche from four climate zones along an aridity gradient, was investigated. The shapes of crystals, which include rare Rosanoffian morphologies, were constant between species from different climate zones, implying that morphology was not affected by rainfall. The distribution and accumulation of CaOx crystals, however, did appear to be climate-related. Distribution was primarily governed by vein density, an architectural trait which has evolved in higher plants in response to increasing aridity. Furthermore, crystals were more abundant in acacias from low rainfall areas, and in phyllodes containing high concentrations of calcium, suggesting that both aridity and soil calcium levels play important roles in the precipitation of CaOx. As crystal formation appears to be calcium-induced, we propose that CaOx crystals in Acacia most likely function in bulk calcium regulation.

  7. Influence of Morphological Characteristics on Physical and Physiological Performances of Tunisian Elite Male Handball Players

    PubMed Central

    Moncef, Cherif; Said, Mohamed; Olfa, Najlaoui; Dagbaji, Gomri

    2012-01-01

    Purpose The purpose of this study was to describe the body structure and morphological characteristics of Tunisian elite handball players, and to determine the effect of these variables on functional and physical performance levels. Methods A sample of 42 male handball players (mean age 21.98±3.24 years; training duration 12 years) at international level was submitted to a test battery comprising morphological, physical and physiological assessments. Tests were yo-yo intermittent recovery test, squat jump test, countermovement jump test, vertical-jump test, and Repeated sprint Ability. Measures for assessment of anthropometric characteristics were age, size, weight, body mass index, body fat, fat mass and thin mass. Results Weight was negatively correlated to the squat jump and the countermovement jump performance. Age, weight, and body composition measures (fat and thin body mass) were additionally negatively related to the maximal oxygen uptake, and to the maximal velocity obtained in the Yo-Yo recovery test. No relationship was found between size, body mass index, body fat and the physical abilities considered. Concerning the effects of physical characteristics on the functional performances, we can note a positive relationship between squat jump, countermovement jump, and the yo-yo recovery test performance. No relationship was found between vertical jump, repeated sprint ability, and the physiological performances. Conclusions Study results point to the existence of strong correlation between morphological and physical characteristics with functional characteristics. In handball, it is possible to have a reliable estimate of anthropometric measurements, physical and physiological performances. PMID:22942992

  8. MIRO1 influences the morphology and intracellular distribution of mitochondria during embryonic cell division in Arabidopsis.

    PubMed

    Yamaoka, Shohei; Nakajima, Masaki; Fujimoto, Masaru; Tsutsumi, Nobuhiro

    2011-02-01

    Regulating the morphology and intracellular distribution of mitochondria is essential for embryo development in animals. However, the importance of such regulation is not clearly defined in plants. The evolutionarily conserved Miro proteins are known to be involved in the regulation of mitochondrial morphology and motility. We previously demonstrated that MIRO1, an Arabidopsis thaliana orthologue of the Miro protein, is required for embryogenesis. An insertional mutation in the MIRO1 gene causes arrest of embryonic cell division, leading to abortion of the embryo at an early stage. Here we investigated the role of MIRO1 in the regulation of mitochondrial behaviour in egg cells and early-stage embryos using GFP-labeled mitochondria. Two-photon laser scanning microscopy revealed that, in miro1 mutant egg cells, mitochondria are abnormally enlarged, although egg cell formation is nearly unaffected. After fertilization and subsequent zygotic cell division, the homozygous miro1 mutant two-celled embryo contained a significantly reduced number of mitochondria in its apical cell compared with the wild type, suggesting that the miro1 mutation inhibits proper intracellular distribution of mitochondria, leading to an arrest of embryonic cell division. Our findings suggest that proper mitochondrial morphology and intracellular distribution are maintained by MIRO1 and are vital for embryonic cell division.

  9. Different fixative methods influence histological morphology and TUNEL staining in mouse testes.

    PubMed

    Wang, Hua; Yang, Lu-Lu; Ji, Yan-Li; Chen, Yuan-Hua; Hu, Jun; Zhang, Cheng; Zhang, Jun; Xu, De-Xiang

    2016-04-01

    Society of Toxicologic Pathology has recommended mDF to fix testes since 2002. However, subsequent studies showed that false TUNEL-positive cells were observed in mDF-fixed testes. This study compared the effects of different fixation methods on histology and TUNEL staining in mouse testes. Results showed that fixation for 24 or 36h in mDF provided better morphologic details in untreated testes, but markedly enhanced false TUNEL-positive staining. To optimize the fixation, testes were fixed using mDF for 6h and then PFA for 18h. Interestingly, fixation using mDF/PFA manifested better morphologic details, and rarely caused false TUNEL-positive cells in testes. Finally, we examined germ cell apoptosis in testes using mDF/PFA fixation in cadmium-treated mice. As expected, cadmium triggered germ cell apoptosis which was well visualized in the mDF/PFA fixed testes. Taken together, mDF plus PFA fixation not only minimizes false TUNEL-positive cells, but also provides integrated morphologic details in testes.

  10. Influence of the local morphology on the surface tension of injection molded polypropylene

    NASA Astrophysics Data System (ADS)

    Gomes, M.; Pontes, A. J.; Viana, J. C.

    2014-05-01

    In this work, we investigate the development of the morphology of an injection molding polypropylene under the local thermomechanical environment imposed during processing, and its effect on the contact angle and, hence, on the surface tension of the moldings. Melt and mold temperatures were varied in two levels. The local thermomechanical environment was characterized by mold filling computational simulations that allow the calculation of thermomechanical variables (e.g., local temperatures, shear stresses) and indices (related to the local morphology development). In order to investigate the structural hierarchy variations of the moldings in the thickness direction, samples from skin to core were used. The molecular orientation and degree of crystallinity were determined as function of the thickness, as well as the contact angle. The variations of the degree of crystallinity were assessed by differential scanning calorimetry. The level of molecular orientation was evaluated by birefringence measurements. The contact angles were measured in deionized water by sessile drop (needle in) method at room temperature, to determine the wettability of the samples. The contact angles were found to vary along the molding thickness in the skin, transition and core layers. These variations are related to the local morphologies developed. Results suggest that water contact angle increases with the level of molecular orientation and for finer microstructures.

  11. Influence of the amount of dietary gluten on gastrointestinal morphology and function in dermatitis herpetiformis.

    PubMed

    Andersson, H; Björkman, A C; Gillberg, R; Kastrup, W; Mobacken, H; Stockbrügger, R

    1984-07-01

    The individual daily intake of gluten was calculated in 45 patients with dermatitis herpetiformis (DH) on the basis of a depth interview about food habits. Gastric and small intestinal morphology and function were studied concurrently. Mean daily gluten intake was estimated to be 15 g, a figure which corresponds well to the average gluten intake in Sweden. There was a significant correlation between the degree of morphological mucosal changes of the small intestine and the quantity of gluten ingested. All patients with jejunal villous atrophy consumed more than 10 g gluten daily and all but one patient with normal jejunal villous structure had a gluten intake of less than 10 g/d. The findings suggest a dose-dependent effect of gluten on the intestinal mucosa. Conversely, the daily gluten intake was not correlated to gastric morphology, gastric acid secretion, serum gastrin levels or serum parietal cell antibodies. Patients with reduced ability to secrete gastric acid did not differ from the remaining patients in this respect. Whereas the coeliac-like enteropathy in DH seems to be caused by ingested gluten, the frequently occurring achlorhydric atrophic gastritis must be assumed to be of different immunopathogenesis.

  12. Abnormal aortic arch morphology in Turner syndrome patients is a risk factor for hypertension.

    PubMed

    De Groote, Katya; Devos, Daniël; Van Herck, Koen; Demulier, Laurent; Buysse, Wesley; De Schepper, Jean; De Wolf, Daniël

    2015-09-01

    Hypertension in Turner syndrome (TS) is a multifactorial, highly prevalent and significant problem that warrants timely diagnosis and rigorous treatment. The objective of this study was to investigate the association between abnormal aortic arch morphology and hypertension in adult TS patients. This was a single centre retrospective study in 74 adult TS patients (age 29.41 ± 8.91 years) who underwent a routine cardiac MRI. Patients were assigned to the hypertensive group (N = 31) if blood pressure exceeded 140/90 mmHg and/or if they were treated with antihypertensive medication. Aortic arch morphology was evaluated on MRI images and initially assigned as normal (N = 54) or abnormal (N = 20), based on the curve of the transverse arch and the distance between the left common carotid-left subclavian artery. We additionally used a new more objective method to describe aortic arch abnormality in TS by determination of the relative position of the highest point of the transverse arch (AoHP). Logistic regression analysis showed that hypertension is significantly and independently associated with age, BMI and abnormal arch morphology, with a larger effect size for the new AoHP method than for the classical method. TS patients with hypertension and abnormal arch morphology more often had dilatation of the ascending aorta. There is a significant association between abnormal arch morphology and hypertension in TS patients, independent of age and BMI, and not related to other structural heart disease. We suggest that aortic arch morphology should be included in the risk stratification for hypertension in TS and propose a new quantitative method to express aortic arch morphology.

  13. Factors influencing teaching style in block-scheduled science classrooms

    NASA Astrophysics Data System (ADS)

    Schoen Giddings, Linda

    This survey study sought to determine the extent to which teachers' personal belief systems, the leadership practices of the principal, and the nature of the organization as a professional learning community influence their teaching methodologies. The data were contributed by 172 South Carolina science teachers from 65 4 x 4 block-scheduled high schools. The teachers were pre-identified by teaching style as predominantly constructivist or traditional. The online survey consisted of two parts. Part I was the CTBA (Torff & Warburton 2005), which examined teacher beliefs regarding critical-thinking classroom strategies. Part II was the short form of the LOLSO Project Questionnaires (Shins et al., 2002), which examined teacher perceptions of their principal as a transformational leader and of their school as a learning organization. Logistic regression analysis identified two significant factors differentiating constructivist and traditional teachers. Traditional teachers were more likely to believe that low critical-thinking strategies were appropriate strategies for use in the classroom and constructivist teachers were more likely to perceive their schools as learning organizations. These two factors, when entered into the logistic regression predictive equation, could predict group membership with a 61% accuracy level. While not a differentiating factor, there was also a strong correlation between leadership and organizational learning (r = .86). These findings are consistent with other research that has found that schools which are learning organizations support more constructivist pedagogy and student-centered classrooms and are dependent upon strong support from school leadership.

  14. Call-related factors influencing output power from mobile phones.

    PubMed

    Hillert, Lena; Ahlbom, Anders; Neasham, David; Feychting, Maria; Järup, Lars; Navin, Roshan; Elliott, Paul

    2006-11-01

    Mobile phone use is increasing but there is also concern for adverse health effects. Well-designed prospective studies to assess several health outcomes are required. In designing a study of mobile phone use, it is important to assess which factors need to be considered in classifying the exposure to radiofrequency fields (RF). A pilot study was performed in Sweden and in the UK 2002 to 2003 to test the feasibility of recruiting a cohort of mobile phone users from a random population sample and from mobile phone subscription lists for a prospective study. As one part of this pilot study, different factors were evaluated regarding possible influence on the output power of the phones. By local switch logging, information on calls made from predefined subscriptions or dedicated handsets were obtained and the output power of phones during calls made indoors and outdoors, in moving and stationary mode, and in rural as well in urban areas were compared. In this experiment, calls were either 1, 1.5 or 5 min long. The results showed that high mobile phone output power is more frequent in rural areas whereas the other factors (length of call, moving/stationary, indoor/outdoor) were of less importance. Urban and rural area should be considered in an exposure index for classification of the exposure to RF from mobile phones and may be assessed by first base station during mobile phone calls or, if this information is not available, possibly by using home address as a proxy.

  15. Factors influencing computer literacy of Taiwan and South Korea nurses.

    PubMed

    Hsu, Hui-Mei; Hou, Ying-Hui; Chang, I-Chiu; Yen, David C

    2009-04-01

    Healthcare is experiencing a major transformation in its information technology base. Hospitals are adopting information technology (IT) to reduce costs and increase competitiveness. IT applications in healthcare are trending towards electronic patient records and even health records. Therefore, practices in nursing are also affected by IT. Many researchers have studied what computer literacy a nurse should possess, but have focused less on factors that actually impact computer literacy. The purposes of this study are to examine current computer literacy levels of nurses, and to indicate what variables influence their computer literacy. Taiwan and South Korea both implemented a national health insurance system, and used state-of-the art IT to provide higher volume and better quality of services. The data were collected from two case hospitals which are located in Taiwan and South Korea, respectively. By using a structured questionnaire, a total of 203 nurses responded; 104 from Taiwan and 99 from South Korea. The results revealed that personal innovativeness in IT, computer education, and age are significant factors that affected computer literacy levels. These factors serve as reference for administrators and executives in hospitals, or nursing educators seeking the data necessary to make decisions on curriculum.

  16. A critical review on factors influencing fermentative hydrogen production.

    PubMed

    Kothari, Richa; Kumar, Virendra; Pathak, Vinayak V; Ahmad, Shamshad; Aoyi, Ochieng; Tyagi, V V

    2017-03-01

    Biohydrogen production by dark fermentation of different waste materials is a promising approach to produce bio-energy in terms of renewable energy exploration. This communication has reviewed various influencing factors of dark fermentation process with detailed account of determinants in biohydrogen production. It has also focused on different factors such as improved bacterial strain, reactor design, metabolic engineering and two stage processes to enhance the bioenergy productivity from substrate. The study also suggest that complete utilization of substrates for biological hydrogen production requires the concentrated research and development for efficient functioning of microorganism with integrated application for energy production and bioremediation. Various studies have been taken into account here, to show the comparative efficiency of different substrates and operating conditions with inhibitory factors and pretreatment option for biohydrogen production. The study reveals that an extensive research is needed to observe field efficiency of process using low cost substrates and integration of dark and photo fermentation process. Integrated approach of fermentation process will surely compete with conventional hydrogen process and replace it completely in future.

  17. Social and ecological factors influencing offspring survival in wild macaques

    PubMed Central

    Kerhoas, Daphne; Perwitasari-Farajallah, Dyah; Agil, Muhammad; Widdig, Anja

    2014-01-01

    Premature loss of offspring decreases direct fitness of parents. In gregarious mammals, both ecological and social variables impact offspring survival and may interact with each other in this regard. Although a number of studies have investigated factors influencing offspring loss in mammals, we still know very little on how different factors interact with one another. We therefore investigated fetal and infant mortality in 3 large groups of wild crested macaques (Macaca nigra) over a period of up to 5 years by including potential social causes such as maternal dominance rank, male immigration, between group encounters, and ecological conditions such as rainfall in a multivariate survival analysis using Cox proportional hazards model. Infant but not fetal survival was most impaired after a recent takeover of the alpha-male position by an immigrant male. Furthermore, infant survival probability increased when there was an increase in number of group adult females and rainfall. Fetal survival probability also increased with an increase of these 2 factors, but more in high-ranking than low-ranking females. Fetal survival, unlike that of infants, was also improved by an increase of intergroup encounter rates. Our study thus stresses the importance of survival analyses using a multivariate approach and encompassing more than a single offspring stage to investigate the determinants of female direct fitness. We further provide evidence for fitness costs and benefits of group living, possibly deriving from high pressures of both within- and between-group competition, in a wild primate population. PMID:25214754

  18. Factors influencing the stream-aquifer flow exchange coefficient.

    PubMed

    Morel-Seytoux, Hubert J; Mehl, Steffen; Morgado, Kyle

    2014-01-01

    Knowledge of river gain from or loss to a hydraulically connected water table aquifer is crucial in issues of water rights and also when attempting to optimize conjunctive use of surface and ground waters. Typically in groundwater models this exchange flow is related to a difference in head between the river and some point in the aquifer, through a "coefficient." This coefficient has been defined differently as well as the location for the head in the aquifer. This paper proposes a new coefficient, analytically derived, and a specific location for the point where the aquifer head is used in the difference. The dimensionless part of the coefficient is referred to as the SAFE (stream-aquifer flow exchange) dimensionless conductance. The paper investigates the factors that influence the value of this new conductance. Among these factors are (1) the wetted perimeter of the cross-section, (2) the degree of penetration of the cross-section, and (3) the shape of the cross-section. The study shows that these factors just listed are indeed ordered in their respective level of importance. In addition the study verifies that the analytical correct value of the coefficient is matched by finite difference simulation only if the grid system is sufficiently fine. Thus the use of the analytical value of the coefficient is an accurate and efficient alternative to ad hoc estimates for the coefficient typically used in finite difference and finite element methods.

  19. Perceptual factors that influence use of computer enhanced visual displays

    NASA Technical Reports Server (NTRS)

    Littman, David; Boehm-Davis, Debbie

    1993-01-01

    This document is the final report for the NASA/Langley contract entitled 'Perceptual Factors that Influence Use of Computer Enhanced Visual Displays.' The document consists of two parts. The first part contains a discussion of the problem to which the grant was addressed, a brief discussion of work performed under the grant, and several issues suggested for follow-on work. The second part, presented as Appendix I, contains the annual report produced by Dr. Ann Fulop, the Postdoctoral Research Associate who worked on-site in this project. The main focus of this project was to investigate perceptual factors that might affect a pilot's ability to use computer generated information that is projected into the same visual space that contains information about real world objects. For example, computer generated visual information can identify the type of an attacking aircraft, or its likely trajectory. Such computer generated information must not be so bright that it adversely affects a pilot's ability to perceive other potential threats in the same volume of space. Or, perceptual attributes of computer generated and real display components should not contradict each other in ways that lead to problems of accommodation and, thus, distance judgments. The purpose of the research carried out under this contract was to begin to explore the perceptual factors that contribute to effective use of these displays.

  20. Factors influencing improved attendance in the UK fire service

    PubMed Central

    Hinckley, P.

    2016-01-01

    Background Sickness absence rates in the UK continue to exceed those in much of the developed world, with an annual cost to employers of £29 billion. Rates of sickness absence in the public sector are higher than those in the private sector, with the exception of the fire service where they are consistently lower. Aims To understand the influences that increase attendance among operational firefighters. Methods A series of semi-structured interviews undertaken with operational staff to explore their attitudes to sickness absence. Results Review and analysis of participant responses identified a number of key themes, namely employee well-being, including physical fitness and mental health; employee engagement with the fire service as manifested by culture, experience, nature of the job and leadership; organizational factors including the staffing model and relationship with occupational health services and policy, which describes both refinements to and implementation of targeted policies. Conclusions Previously observed factors such as improved fitness and the distinct firefighter culture play a role, yet other factors emerged that could explain the differences. These include the greater work–life balance offered by their shift patterns, the terms and conditions of employment and perhaps most importantly the evolution of precisely targeted policies that understand the unique nature of the operational fire service. PMID:27810889

  1. Proximate and landscape factors influence grassland bird distributions

    USGS Publications Warehouse

    Cunningham, M.A.; Johnson, D.H.

    2006-01-01

    Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the Sheyenne National Grassland in North Dakota, USA. The Grassland contains a diverse array of grassland and woodland habitats. We surveyed breeding birds on 2015 100 m long transect segments during 2002 and 2003. We modeled the occurrence of 19 species in relation to habitat features (percentages of grassland, woodland, shrubland, and wetland) within each 100-m segment and to tree cover within 200-1600 m of the segment. We used information-theoretic statistical methods to compare models and variables. At the proximate scales, tree cover was the most important variable, having negative influences on 13 species and positive influences on two species. In a comparison of multiple scales, models with only proximate variables were adequate for some species, but models combining proximate with landscape information were best for 17 of 19 species. Landscape-only models were rarely competitive. Combined models at the largest scales (800-1600 m) were best for 12 of 19 species. Seven species had best models including 1600-m landscapes plus proximate factors in at least one year. These were Wilson's Phalarope (Phalaropus tricolor), Sedge Wren (Cistothorus platensis), Field Sparrow (Spizella pusilla), Grasshopper Sparrow (Ammodramus savannarum), Bobolink (Dolychonix oryzivorus), Red-winged Blackbird (Agelaius phoeniceus), and Brown-headed Cowbird (Molothrus ater). These seven are small-bodied species; thus larger-bodied species do not necessarily respond most to the largest landscapes. Our findings suggest that birds respond to habitat features at a variety of

  2. Proximate and landscape factors influence grassland bird distributions.

    PubMed

    Cunningham, Mary Ann; Johnson, Douglas H

    2006-06-01

    Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the Sheyenne National Grassland in North Dakota, USA. The Grassland contains a diverse array of grassland and woodland habitats. We surveyed breeding birds on 2015 100 m long transect segments during 2002 and 2003. We modeled the occurrence of 19 species in relation to habitat features (percentages of grassland, woodland, shrubland, and wetland) within each 100-m segment and to tree cover within 200-1600 m of the segment. We used information-theoretic statistical methods to compare models and variables. At the proximate scales, tree cover was the most important variable, having negative influences on 13 species and positive influences on two species. In a comparison of multiple scales, models with only proximate variables were adequate for some species, but models combining proximate with landscape information were best for 17 of 19 species. Landscape-only models were rarely competitive. Combined models at the largest scales (800-1600 m) were best for 12 of 19 species. Seven species had best models including 1600-m landscapes plus proximate factors in at least one year. These were Wilson's Phalarope (Phalaropus tricolor), Sedge Wren (Cistothorus platensis), Field Sparrow (Spizella pusilla), Grasshopper Sparrow (Ammodramus savannarum), Bobolink (Dolychonix oryzivorus), Red-winged Blackbird (Agelaius phoeniceus), and Brown-headed Cowbird (Molothrus ater). These seven are small-bodied species; thus larger-bodied species do not necessarily respond most to the largest landscapes. Our findings suggest that birds respond to habitat features at a variety of

  3. Physicochemical characteristics of drip waters: Influence on mineralogy and crystal morphology of recent cave carbonate precipitates

    NASA Astrophysics Data System (ADS)

    Riechelmann, Sylvia; Schröder-Ritzrau, Andrea; Wassenburg, Jasper A.; Schreuer, Jürgen; Richter, Detlev K.; Riechelmann, Dana F. C.; Terente, Mihai; Constantin, Silviu; Mangini, Augusto; Immenhauser, Adrian

    2014-11-01

    Speleothems are one of the most intensively explored continental archives for palaeoclimate variability. The parameters, however, that control speleothem petrography and its changes with time and space, specifically calcite crystal morphology and carbonate mineralogy, are still poorly understood. In order to shed light on processes and their products, precipitation experiments of recent carbonate crystals on watch glasses and glass plates were performed in seven selected caves. Drip water sites were analysed for their fluid Mg/Ca molar ratio, pH, degree of saturation for calcite and aragonite and drip rates. Corresponding precipitates were analysed with respect to their mineralogy, calcite crystal morphology and Mg/Ca molar ratio of calcite. The following results are found: High fluid Mg/Ca ratios are found only for caves situated in dolostone, thus the hostrock lithology indirectly controls the carbonate mineralogy and calcite crystal morphology of speleothems. The precipitation of aragonite in place of calcite occurred only in dolostone caves and is bound to very specific conditions. These are: high fluid Mg/Ca ratios (⩾0.5), high fluid pH (>8.2) and low fluid saturation indices for calcite (<0.8). These specific conditions are induced by slow drip rates of <0.2 ml/min as often under more arid conditions, causing the precipitation of calcite/aragonite prior to reaching the stalagmite top. Due to this, fluid chemistry is altered, which in turn leads to changes in carbonate mineralogy and geochemistry on the stalagmite top. Calcite growth is inhibited at high fluid Mg/Ca ratios and hence, aragonite precipitation is kinetically stabilised. An increase of the drip water Mg/Ca ratio leads to an increased incorporation of Mg2+ into the calcite crystal lattice and thus, to a change in calcite crystal morphology. Four distinctive changes occur with increasing Mg2+ incorporation: (i) development of new forms (steeper rhombohedra and base pinacoid) at the edges and

  4. Genetic Factors and Host Traits Predict Spore Morphology for a Butterfly Pathogen

    PubMed Central

    Sander, Sarah E.; Altizer, Sonia; de Roode, Jacobus C.; Davis, Andrew K.

    2013-01-01

    Monarch butterflies (Danaus plexippus) throughout the world are commonly infected by the specialist pathogen Ophryocystis elektroscirrha (OE). This protozoan is transmitted when larvae ingest infectious stages (spores) scattered onto host plant leaves by infected adults. Parasites replicate internally during larval and pupal stages, and adult monarchs emerge covered with millions of dormant spores on the outsides of their bodies. Across multiple monarch populations, OE varies in prevalence and virulence. Here, we examined geographic and genetic variation in OE spore morphology using clonal parasite lineages derived from each of four host populations (eastern and western North America, South Florida and Hawaii). Spores were harvested from experimentally inoculated, captive-reared adult monarchs. Using light microscopy and digital image analysis, we measured the size, shape and color of 30 replicate spores per host. Analyses examined predictors of spore morphology, including parasite source population and clone, parasite load, and the following host traits: family line, sex, wing area, and wing color (orange and black pigmentation). Results showed significant differences in spore size and shape among parasite clones, suggesting genetic determinants of morphological variation. Spore size also increased with monarch wing size, and monarchs with larger and darker orange wings tended to have darker colored spores, consistent with the idea that parasite development depends on variation in host quality and resources. We found no evidence for effects of source population on variation in spore morphology. Collectively, these results provide support for heritable variation in spore morphology and a role for host traits in affecting parasite development. PMID:26462429

  5. Factors influencing mortality in acute pancreatitis: can we alter them?

    PubMed

    Pitchumoni, C S; Patel, Nayan M; Shah, Prasanna

    2005-10-01

    Severe acture pancreatitis (SAP), a multisystem disease, is characterized by multiple organ system failure and additionally by local pancreatic complications such as necrosis, abscess, or pseudocyst. The rate of mortality in SAP, which is about 20% of all cases of acute pancreatitis (AP), may be as high as 25%, as in infected pancreatic necrosis. The factors that influence mortality in different degrees are various. Etiology for the episode, age, sex, race, ethnicity, genetic makeup, severity on admission, and the extent and nature of pancreatic necrosis (sterile vs. infected) influence the mortality. Other factors include treatment modalities such as administration of prophylactic antibiotics, the mode of feeding (TPN vs. enteral), ERCP with sphincterotomy, and surgery in selected cases. Epidemiological studies indicate that the incidence of AP is increasing along with an increase in obesity, a bad prognostic factor. Many studies have indicated a worse prognosis in idiopathic AP compared to pancreatitis induced by alcoholism or biliary stone. The risk for SAP after ERCP is the subject of extensive study. AP after trauma, organ transplant, or coronary artery bypass surgery is rare but may be serious. Since Ranson reported early prognostic criteria, a number of attempts have been made to simplify or add new clinical or laboratory studies in the early assessment of severity. Obesity, hemoconcentration on admission, presence of pleural effusion, increased fasting blood sugar, as well as creatinine, elevated CRP in serum, and urinary trypsinogen levels are some of the well-documented factors in the literature. The role of appropriate prophylactic antibiotic therapy although still is highly controversial, in properly chosen cases appears to be beneficial and well accepted in clinical practice. Early enteral nutrition has gained much support and jejunal feeding bypassing the pancreatic stimulatory effect of it in the duodenum is desirable in selected cases. The limited

  6. The influence of pressure and gas flow on size and morphology of titanium oxide nanoparticles synthesized by hollow cathode sputtering

    NASA Astrophysics Data System (ADS)

    Gunnarsson, Rickard; Pilch, Iris; Boyd, Robert D.; Brenning, Nils; Helmersson, Ulf

    2016-07-01

    Titanium oxide nanoparticles have been synthesized via sputtering of a hollow cathode in an argon atmosphere. The influence of pressure and gas flow has been studied. Changing the pressure affects the nanoparticle size, increasing approximately proportional to the pressure squared. The influence of gas flow is dependent on the pressure. In the low pressure regime (107 ≤ p ≤ 143 Pa), the nanoparticle size decreases with increasing gas flow; however, at high pressure (p = 215 Pa), the trend is reversed. For low pressures and high gas flows, it was necessary to add oxygen for the particles to nucleate. There is also a morphological transition of the nanoparticle shape that is dependent on the pressure. Shapes such as faceted, cubic, and cauliflower can be obtained.

  7. Factors influencing experience in crowds - The participant perspective.

    PubMed

    Filingeri, Victoria; Eason, Ken; Waterson, Patrick; Haslam, Roger

    2017-03-01

    Humans encounter crowd situations on a daily basis, resulting in both negative and positive experiences. Understanding how to optimise the participant experience of crowds is important. In the study presented in this paper, 5 focus groups were conducted (35 participants, age range: 21-71 years) and 55 crowd situations observed (e.g. transport hubs, sport events, retail situations). Influences on participant experience in crowds identified by the focus groups and observations included: physical design of crowd space and facilities (layout, queuing strategies), crowd movement (monitoring capacity, pedestrian flow), communication and information (signage, wayfinding), comfort and welfare (provision of facilities, environmental comfort), and public order. It was found that important aspects affecting participant experience are often not considered systematically in the planning of events or crowd situations. The findings point to human factors aspects of crowds being overlooked, with the experiences of participants often poor.

  8. Factors influencing adoption of manure separation technology in The Netherlands.

    PubMed

    Gebrezgabher, Solomie A; Meuwissen, Miranda P M; Kruseman, Gideon; Lakner, Dora; Oude Lansink, Alfons G J M

    2015-03-01

    Manure separation technologies are essential for sustainable livestock operations in areas with high livestock density as these technologies result in better utilization of manure and reduced environmental impact. Technologies for manure separation have been well researched and are ready for use. Their use, however, has been limited to the Netherlands. This paper investigates the role of farm and farmer characteristics and farmers' attitudes toward technology-specific attributes in influencing the likelihood of the adoption of mechanical manure separation technology. The analysis used survey data collected from 111 Dutch dairy farmers in 2009. The results showed that the age and education level of the farmer and farm size are important variables explaining the likelihood of adoption. In addition to farm and farmer characteristics, farmers' attitudes toward the different attributes of manure separation technology significantly affect the likelihood of adoption. The study generates useful information for policy makers, technology developers and distributors in identifying the factors that impact decision-making behaviors of farmers.

  9. Assessment of factors influencing the biomethane yield of maize silages.

    PubMed

    Mayer, Frédéric; Gerin, Patrick A; Noo, Anaïs; Foucart, Guy; Flammang, Jos; Lemaigre, Sébastien; Sinnaeve, Georges; Dardenne, Pierre; Delfosse, Philippe

    2014-02-01

    A large set of maize silage samples was produced to assess the major traits influencing the biomethane production of this crop. The biomass yield, the volatile solids contents and the biochemical methane potential (BMP) were measured to calculate the biomethane yield per hectare (average=7266m(3)ha(-1)). The most influential factor controlling the biomethane yield was the cropping environment. The biomass yield had more impact than the anaerobic digestibility. Nevertheless, the anaerobic digestibility of maize silages was negatively affected by high VS content in mature maize. Late maturing maize varieties produced high biomass yield with high digestibility resulting in high biomethane yield per hectare. The BMP was predicted with good accuracy using solely the VS content.

  10. Factors influencing the frequency of children's consumption of soft drinks.

    PubMed

    Pettigrew, Simone; Jongenelis, Michelle; Chapman, Kathy; Miller, Caroline

    2015-08-01

    Among other focus areas, interventions designed to improve children's diets need to address key factors contributing to children's consumption of sugar-sweetened beverages. The present study employed structural equation modelling to investigate the relationship between a broad range of predictor variables and the frequency with which Australian children consume soft drinks. In total, 1302 parents of children aged 8 to 14 years responded to an online survey about their children's food consumption behaviours. Soft drink consumption frequency was primarily influenced by parents' attitudes to soft drinks, children's pestering behaviours, and perceived social norms relating to children's consumption of these products. Importantly, pestering and social norms had significant direct effects on consumption frequency in addition to indirect effects via their impact on parents' attitudes to soft drink.

  11. Factors influencing the detection of beach plastic debris.

    PubMed

    Lavers, Jennifer L; Oppel, Steffen; Bond, Alexander L

    2016-08-01

    Marine plastic pollution is a global problem with considerable ecological and economic consequences. Quantifying the amount of plastic in the ocean has been facilitated by surveys of accumulated plastic on beaches, but existing monitoring programmes assume the proportion of plastic detected during beach surveys is constant across time and space. Here we use a multi-observer experiment to assess what proportion of small plastic fragments is missed routinely by observers, and what factors influence the detection probability of different types of plastic. Detection probability across the various types of plastic ranged from 60 to 100%, and varied considerably by observer, observer experience, and biological material present on the beach that could be confused with plastic. Blue fragments had the highest detection probability, while white fragments had the lowest. We recommend long-term monitoring programmes adopt survey designs accounting for imperfect detection or at least assess the proportion of fragments missed by observers.

  12. Factors that influence the performance of experienced speech recognition users.

    PubMed

    Koester, Heidi Horstmann

    2006-01-01

    Performance on automatic speech recognition (ASR) systems for users with physical disabilities varies widely between individuals. The goal of this study was to discover some key factors that account for that variation. Using data from 23 experienced ASR users with physical disabilities, the effect of 20 different independent variables on recognition accuracy and text entry rate with ASR was measured using bivariate and multivariate analyses. The results show that use of appropriate correction strategies had the strongest influence on user performance with ASR. The amount of time the user spent on his or her computer, the user's manual typing speed, and the speed with which the ASR system recognized speech were all positively associated with better performance. The amount or perceived adequacy of ASR training did not have a significant impact on performance for this user group.

  13. Climatic factors influencing triatomine occurrence in Central-West Brazil

    PubMed Central

    Pereira, Joyce Mendes; de Almeida, Paulo Silva; de Sousa, Adair Vieira; de Paula, Aécio Moraes; Machado, Ricardo Bomfim; Gurgel-Gonçalves, Rodrigo

    2013-01-01

    We estimated the geographic distributions of triatomine species in Central-West Region of Brazil (CW) and analysed the climatic factors influencing their occurrence. A total of 3,396 records of 27 triatomine species were analysed. Using the maximum entropy method, ecological niche models were produced for eight species occurring in at least 20 municipalities based on 13 climatic variables and elevation. Triatoma sordida and Rhodnius neglectus were the species with the broadest geographic distributions in CW Brazil. The Cerrado areas in the state of Goiás were found to be more suitable for the occurrence of synanthropic triatomines than the Amazon forest areas in the northern part of the state of Mato Grosso. The variable that best explains the evaluated models is temperature seasonality. The results indicate that almost the entire region presents climatic conditions that are appropriate for at least one triatomine species. Therefore, it is recommended that entomological surveillance be reinforced in CW Brazil. PMID:23778666

  14. Structural, morphological and catalytic characterization of neutral Ag salt of 12-tungstophosphoric acid: Influence of preparation conditions

    NASA Astrophysics Data System (ADS)

    Holclajtner-Antunović, Ivanka; Bajuk-Bogdanović, Danica; Popa, Alexandru; Nedić Vasiljević, Bojana; Krstić, Jugoslav; Mentus, Slavko; Uskoković-Marković, Snežana

    2015-02-01

    The objective of this study is the structural and morphological characterization of the Ag3PW12O40 salts (AgWPA) of 12-tungstophosphoric acid (WPA) obtained under different preparation conditions and testing of their acid catalytic activity in dehydration of ethanol. The structure, morphology and physicochemical characteristics were determined by Fourier transform infrared (FT-IR) and Raman spectroscopy, X-ray diffraction (XRD), nitrogen physisorption at -196 °C, scanning electron microscopy (SEM) and differential thermal (DTA) and thermogravimetric analysis (TGA). It is shown that the preparation process has a significant influence on the morphological properties of the obtained materials which may be explained by the supposed mechanism of the formation of nanocrystallite‧s aggregates with more or less epitaxial connection. Neutral AgWPA obtained by filtration from supernatant forms porous aggregates of a symmetric dodecahedral shape, having average sizes about 2 μm. This sample shows higher specific area in comparison with the salt obtained by evaporation due to the higher micropore volume, while mesopore volumes are the same for both salts. Thus conversion of ethanol and selectivities of the main products, ethylene and diethyl ether, are almost the same and constant for both prepared salts, while their values are changed over the reaction time for the parent WPA acid.

  15. Influence of alkali metal cations on the thermal, mechanical and morphological properties of rectorite/chitosan bio-nanocomposite films.

    PubMed

    Babul Reddy, A; Jayaramudu, J; Siva Mohan Reddy, G; Manjula, B; Sadiku, E R

    2015-05-20

    The main theme of this work is to study the influence of ion-exchangeable alkali metal cations, such as: Li(+), Na(+), K(+), and Cs(+) on the thermal, mechanical and morphological properties. In this regard, a set of rectorite/chitosan (REC-CS) bio-nanocomposite films (BNCFs) was prepared by facile reaction of chitosan with ion-exchanged REC clay. The microstructure and morphology of BNCFs were investigated with XRD, TEM, SEM and AFM. Thermal and tensile properties of BNCFs were also investigated. As revealed from TEM and XRD results, the BNCFs featured a mixed morphology. Some intercalated clay sheets, together with nano-sized clay tactoids were obtained in LiREC/CS, NaREC/CS and KREC/CS of the BNCFs. From fractured surface study, via SEM, it was observed that the dispersion of chitosan polymer attaches to (and covers) the clay platelets. FTIR confirmed strong hydrogen bonds between clay and chitosan polymer. In addition, the thermal stabilities significantly varied when alkali metal cations varied from Li(+) to Cs(+). The BNCFs featured high tensile strengths (up to 84 MPa) and tensile moduli (up to 45 GPa). After evaluating these properties of BNCFs, we came to conclusion that these bio-nano composites can be used for packaging applications.

  16. Influence of processing conditions on the morphology of expanded perlite/polypropylene composites

    NASA Astrophysics Data System (ADS)

    Mattausch, H.; Laske, S.; Cirar, K.; Flachberger, H.; Holzer, C.

    2014-05-01

    Perlite is an oversaturated, volcanic, glassy rock, which has chemically bound water from 2 to 5 wt%. Upon heating, perlite can be expanded up to 20 times of its original volume. Important applications are in the field of building industry, in refrigeration engineering or the pharmaceutical industry. As mineral filler in polymers, expanded perlite can increase the thermal conductivity, the viscosity and the mechanical properties of polypropylene composites. But there are still many challenges that must be analyzed to reach the full potential of those composites. This research work focuses on the morphology of expanded perlite/polypropylene (PP) compounds and the interactions between filler and polymer. To achieve good performance a homogenous dispersion of the filler in the polymer matrix is needed because the enhancement of the material correlates strongly with the morphology of the composite. Therefore it is necessary to characterize the microstructure of these materials in order to establish adequate structure-process-property relationships. The expanded perlite/PP composites were compounded with a co-rotating twin screw extruder Theysohn TSK 30/40D. For producing the closed cell expanded perlite a new technology, the bublon process, was used. For the material characterization two particles sizes were chosen and the filler content was varied at 5, 10 and 15 wt%. For the analysis of the effects of the screw geometry, two setups have been chosen for the processing of the materials. The produced materials were analyzed by scanning electron microscope (SEM) and tensile testing. The results show a reinforcement effect of the filler and differences in the inner structure of expanded perlite and in the morphology.

  17. Influence of bill and foot morphology on the ectoparasites of barn owls.

    PubMed

    Bush, Sarah E; Villa, Scott M; Boves, Than J; Brewer, Dallas; Belthoff, James R

    2012-04-01

    Preening is the principle behavioral defense used by birds to combat ectoparasites. Most birds have a small overhang at the tip of their bills that is used to shear through the tough cuticle of ectoparasitic arthropods, making preening much more efficient. Birds may also scratch with their feet to defend against ectoparasites. This is particularly important for removing ectoparasites on the head, which birds cannot preen. Scratching may be enhanced by the comb-like serrations that are found on the claws of birds in many avian families. We examined the prevalence and intensity of ectoparasites of barn owls (Tyto alba pratincola) in southern Idaho in relation to bill hook length and morphological characteristics of the pectinate claw. The barn owls in our study were infested with 3 species of lice (Phthiraptera: Ischnocera): Colpocephalum turbinatum , Kurodaia subpachygaster, and Strigiphilus aitkeni . Bill hook length was associated with the prevalence of these lice. Owls with longer hooks were more likely to be infested with lice. Conventional wisdom suggests that the bill morphology of raptors has been shaped by selection for efficient foraging; our data suggest that hook morphology may also play a role in ectoparasite defense. The number of teeth on the pectinate claw was also associated with the prevalence of lice. Owls that had claws with more teeth were less likely to be infested with lice, which suggests that larger pectinate claws may offer relatively more protection against ectoparasitic lice. Experiments that manipulate the bill hook and pectinate claw are needed to confirm whether these host characters are involved in ectoparasite defense. Finally, we recovered mammalian ectoparasites from 4 barn owls. We recovered species of mammalian lice (Phthiraptera:Anoplura) and fleas (Siphonaptera) that are commonly found on microtine rodents. The owls probably acquired these parasites from recently eaten prey. This represents 1 of the few documented cases of

  18. Influence of processing conditions on the morphology of expanded perlite/polypropylene composites

    SciTech Connect

    Mattausch, H. E-mail: stephan.laske@unileoben.ac.at; Laske, S. E-mail: stephan.laske@unileoben.ac.at; Holzer, C.; Cirar, K. E-mail: helmut.flachberger@unileoben.ac.at; Flachberger, H. E-mail: helmut.flachberger@unileoben.ac.at

    2014-05-15

    Perlite is an oversaturated, volcanic, glassy rock, which has chemically bound water from 2 to 5 wt%. Upon heating, perlite can be expanded up to 20 times of its original volume. Important applications are in the field of building industry, in refrigeration engineering or the pharmaceutical industry. As mineral filler in polymers, expanded perlite can increase the thermal conductivity, the viscosity and the mechanical properties of polypropylene composites. But there are still many challenges that must be analyzed to reach the full potential of those composites. This research work focuses on the morphology of expanded perlite/polypropylene (PP) compounds and the interactions between filler and polymer. To achieve good performance a homogenous dispersion of the filler in the polymer matrix is needed because the enhancement of the material correlates strongly with the morphology of the composite. Therefore it is necessary to characterize the microstructure of these materials in order to establish adequate structure-process-property relationships. The expanded perlite/PP composites were compounded with a co-rotating twin screw extruder Theysohn TSK 30/40D. For producing the closed cell expanded perlite a new technology, the bublon process, was used. For the material characterization two particles sizes were chosen and the filler content was varied at 5, 10 and 15 wt%. For the analysis of the effects of the screw geometry, two setups have been chosen for the processing of the materials. The produced materials were analyzed by scanning electron microscope (SEM) and tensile testing. The results show a reinforcement effect of the filler and differences in the inner structure of expanded perlite and in the morphology.

  19. Influence of electropolishing and anodic oxidation on morphology, chemical composition and corrosion resistance of niobium.

    PubMed

    Sowa, Maciej; Greń, Katarzyna; Kukharenko, Andrey I; Korotin, Danila M; Michalska, Joanna; Szyk-Warszyńska, Lilianna; Mosiałek, Michał; Zak, Jerzy; Pamuła, Elżbieta; Kurmaev, Ernst Z; Cholakh, Seif O; Simka, Wojciech

    2014-09-01

    The work presents results of the studies performed on electropolishing of pure niobium in a bath that contained: sulphuric acid, hydrofluoric acid, ethylene glycol and acetanilide. After the electropolishing, the specimens were subjected to anodic passivation in a 1moldm(-3) phosphoric acid solution at various voltages. The surface morphology, thickness, roughness and chemical composition of the resulting oxide layers were analysed. Thusly prepared niobium samples were additionally investigated in terms of their corrosion resistance in Ringer's solution. The electropolished niobium surface was determined to be smooth and lustrous. The anodisation led to the growth of barrier-like oxide layers, which were enriched in phosphorus species.

  20. The influence of crystal morphology on the kinetics of growth of calcium oxalate monohydrate

    NASA Astrophysics Data System (ADS)

    Millan, A.; Sohnel, O.; Grases, F.

    1997-08-01

    The growth of several calcium oxalate monohydrate seeds in the presence and absence of additives (phytate, EDTA and citrate) has been followed by potentiometry measurements. Growth rates have been calculated from precipitate curves by a cubic spline method and represented in logarithmic plots versus supersaturation. Crystal growth kinetics were found to be dependent on crystal morphology, crystal perfection and degree of aggregation. Some seeds were dissolving in supersaturated solutions. Other seeds showed an initial growth phase of high-order kinetics. The effect of the additives was also different on each seed. Three alternative mechanisms for calcium oxalate crystal growth are proposed.

  1. Talking about Relations: Factors Influencing the Production of Relational Descriptions

    PubMed Central

    Baltaretu, Adriana; Krahmer, Emiel J.; van Wijk, Carel; Maes, Alfons

    2016-01-01

    In a production experiment (Experiment 1) and an acceptability rating one (Experiment 2), we assessed two factors, spatial position and salience, which may influence the production of relational descriptions (such as “the ball between the man and the drawer”). In Experiment 1, speakers were asked to refer unambiguously to a target object (a ball). In Experiment 1a, we addressed the role of spatial position, more specifically if speakers mention the entity positioned leftmost in the scene as (first) relatum. The results showed a small preference to start with the left entity, which leaves room for other factors that could influence spatial reference. Thus, in the following studies, we varied salience systematically, by making one of the relatum candidates animate (Experiment 1b), and by adding attention capture cues, first subliminally by priming one relatum candidate with a flash (Experiment 1c), then explicitly by using salient colors for objects (Experiment 1d). Results indicate that spatial position played a dominant role. Entities on the left were mentioned more often as (first) relatum than those on the right (Experiments 1a–d). Animacy affected reference production in one out of three studies (in Experiment 1d). When salience was manipulated by priming visual attention or by using salient colors, there were no significant effects (Experiments 1c, d). In the acceptability rating study (Experiment 2), participants expressed their preference for specific relata, by ranking descriptions on the basis of how good they thought the descriptions fitted the scene. Results show that participants preferred most the description that had an animate entity as the first mentioned relatum. The relevance of these results for models of reference production is discussed. PMID:26903911

  2. Factors influencing organic carbon preservation in marine sediments

    NASA Technical Reports Server (NTRS)

    Canfield, D. E.

    1994-01-01

    The organic matter that escapes decomposition is buried and preserved in marine sediments, with much debate as to whether the amount depends on bottom-water O2 concentration. One group argues that decomposition is more efficient with O2, and hence, organic carbon will be preferentially oxidized in its presence, and preserved in its absence. Another group argues that the kinetics of organic matter decomposition are similar in the presence and absence of O2, and there should be no influence of O2 on preservation. A compilation of carbon preservation shows that both groups are right, depending on the circumstances of deposition. At high rates of deposition, such as near continental margins, little difference in preservation is found with varying bottom-water O2. It is important that most carbon in these sediments decomposes by anaerobic pathways regardless of bottom-water O2. Hence, little influence of bottom-water O2 on preservation would, in fact, be expected. As sedimentation rate drops, sediments deposited under oxygenated bottom water become progressively more aerobic, while euxinic sediments remain anaerobic. Under these circumstances, the relative efficiencies of aerobic and anaerobic decomposition could affect preservation. Indeed, enhanced preservation is observed in low-O2 and euxinic environments. To explore in detail the factors contributing to this enhanced carbon preservation, aspects of the biochemistries of the aerobic and anaerobic process are reviewed. Other potential influences on preservation are also explored. Finally, a new model for organic carbon decomposition, the "pseudo-G" model, is developed. This model couples the degradation of refractory organic matter to the overall metabolic activity of the sediment, and has consequences for carbon preservation due to the mixing together of labile and refractory organic matter by bioturbation.

  3. Factors influencing yield of plateletpheresis using intermittent flow cell separator.

    PubMed

    DAS, S S; Chaudhary, R K; Shukla, J S

    2005-10-01

    Platelet recovery in the recipient is influenced by the transfused dose of platelets, which in turn is dependent on the quality of single donor platelets (SDPs) in terms of platelet yield. Various donor factors such as predonation platelet count and Hemoglobin (Hb) concentration affect the platelet yield. A total of 61 plateletpheresis procedures performed on intermittent flow cell separator (MCS3p, Hemonetics) were evaluated for platelet yield. A relationship between predonation platelet count and Hb concentration with yield of platelets was studied using Pearson Correlation. The mean platelet yield was 2.9 +/- 0.64 x 10(11). While a direct relationship was observed between predonation platelet count and yield (r = 0.51, P < 0.001), no such correlation was noticed with donor Hb concentration (r = -0.05, P > 0.005). The yield was > or =3 x 10(11) in >80% of procedures when the predonation platelet count was > or =250 x 10(3)/mm. Optimization of platelet yield, which is influenced by predonation platelet count, is an emerging issue in blood transfusion services. However, further studies in this regard are needed using more advanced cell separators.

  4. Factors influencing dust exposure: finishing activities in drywall construction.

    PubMed

    Simmons, Catherine E; Jones, Rachael M; Boelter, Fred W

    2011-05-01

    Sanding drywall joint compound is a dusty construction activity. We studied potential factors influencing exposure to respirable and total dust for sanders and bystanders in the area of drywall joint compound finishing in 17 test events within a room-scale isolation chamber. We found the air change rate to be negatively correlated with dust C(twa) both in the sander's personal breathing zone and surrounding area. We could not conclude that sanding tool type systematically influences dust C(twa), but the use of 80-grit abrasive was associated with the highest dust C(twa). We found respirable dusts were uniformly dispersed 1-8.2 m from sanding activities at a fixed location. As anticipated, both respirable and total dust C(twa) in the sander's personal breathing zone are higher than in the surrounding area. The respirable fraction of the total dust mass C(twa) was greater in the surrounding area than in the sander's personal breathing zone. Respirable dust concentrations measured in real time increased over the duration of sanding, exhibiting a temporal trend that is similar to that predicted by the well-mixed box model with contaminant removal by mechanical ventilation only, and continuous emission. Dust concentrations returned to pre-activity (background) levels 2-4 hr after cessation of the sanding activity.

  5. The morphology of green hydra endosymbionts as influenced by host strain and host environment.

    PubMed

    Pardy, R L

    1976-05-01

    The ultrastructure of Chlorella-like algal endosymbionts from the Florida and English strains of green hydra was compared under different host feeding and photoperiodic regimes. Under standard conditions (host fed daily, 12-h photoperiod) the algae from the 2 strains exhibited considerable differences. The English symbionts had a pyrenoid, compact chloroplast membranes and vesiculated polyphosphate bodies. By comparison, Florida symbionts lacked a pyrenoid, had chloroplasts with less compact membranes and exhibited spherical polyphosphate bodies. When maintained in the dark, algae from English hydra lost their pyrenoids, showed great compaction of the chloroplast and developed large, shield-shaped, electron-dense bodies. In contrast, algae from Florida hosts did not exhibit gross ultrastructural modification. Reciprocal cross-transfers of symbionts were made by placing Florida algae in English aposymbiotic (algal-free) hosts and vice versa. After residence in Florida hosts, English symbionts appeared to undergo ultrastructural modifications resulting in a morphology indistinguishable from the native Florida symbionts. Florida algae showed no modifications resulting from residence in English hosts. It thus appears that the English symbiont has great morphological plasticity, as its structure is greatly modified depending upon the host in which it resides and the conditions under which the host is maintained. The results of these studies are discussed and compared with published accounts of free-living Chlorella and with reports dealing with other Chlorella symbionts.

  6. Human aortic endothelial cell morphology influenced by topography of porous silicon substrates.

    PubMed

    Formentín, Pilar; Catalán, Úrsula; Fernández-Castillejo, Sara; Alba, Maria; Baranowska, Malgorzata; Solà, Rosa; Pallarès, Josep; Marsal, Lluís F

    2015-10-01

    Porous silicon has received much attention because of its optical properties and for its usefulness in cell-based biosensing, drug delivery, and tissue engineering applications. Surface properties of the biomaterial are associated with cell adhesion and with proliferation, migration, and differentiation. The present article analyzes the behavior of human aortic endothelial cells in macro- and nanoporous collagen-modified porous silicon samples. On both substrates, cells are well adhered and numerous. Confocal microscopy and scanning electron microscopy were employed to study the effects of porosity on the morphology of the cells. On macroporous silicon, filopodia is not observed but the cell spreads on the surface, increasing the lamellipodia surface which penetrates the macropore. On nanoporous silicon, multiple filopodia were found to branch out from the cell body. These results demonstrate that the pore size plays a key role in controlling the morphology and growth rate of human aortic endothelial cells, and that these forms of silicon can be used to control cell development in tissue engineering as well as in basic cell biology research.

  7. Influence of Zn incorporation in CdS: Structural and morphological studies

    NASA Astrophysics Data System (ADS)

    Mukherjee, A.; Fu, M.; Mitra, P.

    2015-07-01

    In recent years, cadmium zinc sulfide (CdxZn1-xS) alloy compounds have been paid much attention in the fields of opto-electronics, particularly in photovoltaic devices. In this report, the structural, morphological and optical properties of Cdx Zn1-x S films deposited by chemical bath deposition (CBD), which is a very attractive method for low-cost and large-area solar cell applications, has been presented. The as-grown layers were characterized using XRD, EDAX, FESEM, TEM and UV-vis spectrophotometers. Structural characterization by X-ray diffraction and SAED measurement reveals a dominant cubic structure with a minor hexagonal phase for high zinc content films. EDAX analysis shows nearly stoichiometric films with cadmium excess. Close packed and less dissociated surface morphology was observed in the Cdx Zn1-x S ternary thin films with lower Zn2+ content than the higher Zn2+ content one. Agglomeration of nanocrystals for high zinc content films results in enhanced absorption. The mean grain size of Cd0.5 Zn0.5 S calculated from TEM image is ~15 nm. Optical absorption study exhibits a distinct blue shift in band gap energy with enhancement of zinc content in the film.

  8. Plasmid-encoded genes influence exosporium assembly and morphology in Bacillus megaterium QM B1551 spores.

    PubMed

    Manetsberger, Julia; Hall, Elizabeth A H; Christie, Graham

    2015-09-01

    Spores of Bacillus megaterium QM B1551 are encased in a morphologically distinctive exosporium. We demonstrate here that genes encoded on the indigenous pBM500 and pBM600 plasmids are required for exosporium assembly and or stability in spores of this strain. Bioinformatic analyses identified genes encoding orthologues of the B. cereus-family exosporium nap and basal layer proteins within the B. megaterium genome. Transcriptional analyses, supported by electron and fluorescent microscopy, indicate that the pole-localized nap, identified here for the first time in B. megaterium QM B1551 spores, is comprised of the BclA1 protein. The role of the BxpB protein, which forms the basal layer of the exosporium in B. cereus spores, is less clear since spores of a null mutant strain display an apparently normal morphology. Retention of the localized nap in bxpB null spores suggests that B. megaterium employs an alternative mechanism to that used by B. cereus spores in anchoring the nap to the spore surface.

  9. Beryllium deposition on International Thermonuclear Experimental Reactor first mirrors: Layer morphology and influence on mirror reflectivity

    SciTech Connect

    De Temmerman, G.; Baldwin, M. J.; Doerner, R. P.; Nishijima, D.; Seraydarian, R.; Schmid, K.; Kost, F.; Linsmeier, Ch.; Marot, L.

    2007-10-15

    Metallic mirrors will be essential components of the optical diagnostic systems in the International Thermonuclear Experimental Reactor (ITER). Reliability of these systems may be affected by mirror reflectivity changes induced by erosion and/or deposition of impurities (carbon, beryllium). The present study aims to assess the effect of beryllium (Be) deposition on the reflectivity of metallic mirrors and to collect data on the optical quality of these layers in terms of morphology, roughness, etc. Mirrors from molybdenum and copper were exposed in the PISCES-B linear plasma device to collect eroded material from graphite and beryllium targets exposed to beryllium-seeded deuterium plasma. After exposure, relative reflectivity of the mirrors was measured and different surface analysis techniques were used to investigate the properties of the deposited layers. Be layers formed in PISCES-B exhibit high levels of porosity which makes the reflectivity of the Be layers much lower than the reflectivity of pure Be. It is found that if Be deposition occurs on ITER first mirrors, the reflectivity of the coated mirrors will strongly depend on the layer morphology, which in turn depends on the deposition conditions.

  10. Plasmid-encoded genes influence exosporium assembly and morphology in Bacillus megaterium QM B1551 spores

    PubMed Central

    Manetsberger, Julia; Hall, Elizabeth A. H.; Christie, Graham

    2015-01-01

    Spores of Bacillus megaterium QM B1551 are encased in a morphologically distinctive exosporium. We demonstrate here that genes encoded on the indigenous pBM500 and pBM600 plasmids are required for exosporium assembly and or stability in spores of this strain. Bioinformatic analyses identified genes encoding orthologues of the B. cereus-family exosporium nap and basal layer proteins within the B. megaterium genome. Transcriptional analyses, supported by electron and fluorescent microscopy, indicate that the pole-localized nap, identified here for the first time in B. megaterium QM B1551 spores, is comprised of the BclA1 protein. The role of the BxpB protein, which forms the basal layer of the exosporium in B. cereus spores, is less clear since spores of a null mutant strain display an apparently normal morphology. Retention of the localized nap in bxpB null spores suggests that B. megaterium employs an alternative mechanism to that used by B. cereus spores in anchoring the nap to the spore surface. PMID:26316548

  11. The Influence of Genome and Cell Size on Brain Morphology in Amphibians.

    PubMed

    Roth, Gerhard; Walkowiak, Wolfgang

    2015-08-10

    In amphibians, nerve cell size is highly correlated with genome size, and increases in genome and cell size cause a retardation of the rate of development of nervous (as well as nonnervous) tissue leading to secondary simplification. This yields an inverse relationship between genome and cell size on the one hand and morphological complexity of the tectum mesencephali as the main visual center, the size of the torus semicircularis as the main auditory center, the size of the amphibian papilla as an important peripheral auditory structure, and the size of the cerebellum as a major sensorimotor center. Nervous structures developing later (e.g., torus and cerebellum) are more affected by secondary simplification than those that develop earlier (e.g., the tectum). This effect is more prominent in salamanders and caecilians than in frogs owing to larger genome and cells sizes in the former two taxa. We hypothesize that because of intragenomic evolutionary processes, important differences in brain morphology can arise independently of specific environmental selection.

  12. The influence of ternary alloying elements on the Al-Si eutectic microstructure and the Si morphology

    NASA Astrophysics Data System (ADS)

    Darlapudi, A.; McDonald, S. D.; Terzi, S.; Prasad, A.; Felberbaum, M.; StJohn, D. H.

    2016-01-01

    The influence of the ternary alloying elements Cu, Mg and Fe on the Al-Si eutectic microstructure is investigated using a commercial purity Al-10 wt%Si alloy in unmodified and Sr-modified conditions. A change in the Al-Si eutectic microstructure was associated with a change in the nucleation density of the eutectic grains caused by the addition of ternary alloying elements. When the ternary alloying element addition resulted in an increase in the eutectic nucleation frequency, a fibrous to flake-like transition was observed within the eutectic grain. When the ternary alloying element addition decreased the eutectic nucleation frequency significantly, a change in the eutectic morphology from flake-like to a mixture of flake-like and fibrous morphologies was observed. The mechanism of Al-Si eutectic modification is discussed. The growth velocity of the eutectic grain - liquid interface and the constitutional driving force available for growth are proposed as important parameters that influence the degree of eutectic modification in Al-Si alloys.

  13. Influence of abiotic factors on the antimicrobial activity of chitosan.

    PubMed

    Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

    2013-12-01

    In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis.

  14. Factors influencing post-exercise plasma protein carbonyl concentration.

    PubMed

    Wadley, Alex J; Turner, James E; Aldred, Sarah

    2016-01-01

    Exercise of sufficient intensity and duration can cause acute oxidative stress. Plasma protein carbonyl (PC) moieties are abundant, chemically stable, and easily detectable markers of oxidative stress that are widely used for the interpretation of exercise-induced changes in redox balance. Despite many studies reporting acute increases in plasma PC concentration in response to exercise, some studies, including those from our own laboratory have shown decreases. This review will discuss the differences between studies reporting increases, decreases, and no change in plasma PC concentration following exercise in humans; highlighting participant physiology (i.e. training status) and study design (i.e. intensity, duration, and novelty of the exercise bout) as the main factors driving the direction of the PC response to exercise. The role of the 20S proteasome system is proposed as a possible mechanism mediating the clearance of plasma PC following exercise. Resting and exercise-induced differences in plasma protein composition and balance between tissues are also discussed. We suggest that exercise may stimulate the clearance of plasma PC present at baseline, whereas simultaneously increasing reactive oxygen species production that facilitates the formation of new PC groups. The balance between these two processes likely explains why some studies have reported no change or even decreases in plasma PC level post-exercise when other biomarkers of oxidative stress (e.g. markers of lipid peroxidation) were elevated. Future studies should determine factors that influence the balance between PC clearance and formation following acute exercise.

  15. Factors influencing HIV vaccine community engagement in the urban South.

    PubMed

    Frew, Paula M; del Rio, Carlos; Clifton, Sarah; Archibald, Matthew; Hormes, Joseph T; Mulligan, Mark J

    2008-08-01

    The purpose of this exploratory study was to examine personal characteristics, socio-environmental conditions, and motivational factors that potentially influence HIV vaccine research community engagement. Specifically, the study identified predictive aspects that may aid in future community program development on HIV vaccine issues. A cross-sectional survey consisting of evaluative measures, demographics, social interaction, and health information-seeking behaviors was conducted. Participants were a diverse group of 452 adults (>or=18 years) at HIV vaccine awareness-building and community education gatherings in Atlanta. The sample included large numbers of women (n=251) and minorities (n=224). In multivariate analysis, the overall logistic regression model was significant, with a resulting coefficient of determination (Nagelkerke R(2)) of .505. Highly significant factors included an excellent activity/event rating (log odds beta = 4.521, P< .001), White race (beta= -.835, P= .005), greater educational attainment (beta= .725, P= .011), travel distance (beta = 1.186, P= .002), and excellent perception of the study site (beta=2.131, P< .001). Subgroup analyses by gender and race revealed similar findings. These data demonstrate the importance of building a favorable study site image and gaining familiarity in the community to aid in the promotion of HIV vaccine research on an ongoing basis.

  16. Factors influencing deoxynivalenol accumulation in small grain cereals.

    PubMed

    Wegulo, Stephen N

    2012-11-06

    Deoxynivalenol (DON) is a mycotoxin produced by the plant pathogenic fungi Fusarium graminearum and F. culmorum. These and other closely related fungi cause a disease known as Fusarium head blight (FHB) in small grain cereals. Other mycotoxins produced by FHB-causing fungi include nivalenol, T-2 toxin, and zearalenone. Ingestion of mycotoxin-contaminated food and feed can lead to toxicosis in humans and animals, respectively. DON is the predominant and most economically important of these mycotoxins in the majority of small grain-producing regions of the world. This review examines the factors that influence DON accumulation in small grain cereals from an agricultural perspective. The occurrence and economic importance of FHB and DON in small grain cereals, epidemiological factors and cereal production practices that favor FHB development and DON accumulation in grain under field conditions, and regulatory/advisory standards for DON in food and feed are discussed. This information can be used to develop strategies that reduce DON accumulation in grain before harvest and to mitigate the human and animal health risks associated with DON contamination of food and feed.

  17. Emotional and Social Factors influence Poker Decision Making Accuracy.

    PubMed

    Laakasuo, Michael; Palomäki, Jussi; Salmela, Mikko

    2015-09-01

    Poker is a social game, where success depends on both game strategic knowledge and emotion regulation abilities. Thus, poker provides a productive environment for studying the effects of emotional and social factors on micro-economic decision making. Previous research indicates that experiencing negative emotions, such as moral anger, reduces mathematical accuracy in poker decision making. Furthermore, various social aspects of the game—such as losing against "bad players" due to "bad luck"—seem to fuel these emotional states. We designed an Internet-based experiment, where participants' (N = 459) mathematical accuracy in five different poker decision making tasks were assessed. In addition, we manipulated the emotional and social conditions under which the tasks were presented, in a 2 × 2 experimental setup: (1) Anger versus neutral emotional state—participants were primed either with an anger-inducing, or emotionally neutral story, and (2) Social cue versus non-social cue—during the tasks, either an image of a pair of human eyes was "following" the mouse cursor, or an image of a black moving box was presented. The results showed that anger reduced mathematical accuracy of decision making only when participants were "being watched" by a pair of moving eyes. Experienced poker players made mathematically more accurate decisions than inexperienced ones. The results contribute to current understanding on how emotional and social factors influence decision making accuracy in economic games.

  18. Abiotic factors influence plant storage lipid accumulation and composition.

    PubMed

    Singer, Stacy D; Zou, Jitao; Weselake, Randall J

    2016-02-01

    The demand for plant-derived oils has increased substantially over the last decade, and is sure to keep growing. While there has been a surge in research efforts to produce plants with improved oil content and quality, in most cases the enhancements have been small. To add further complexity to this situation, substantial differences in seed oil traits among years and field locations have indicated that plant lipid biosynthesis is also influenced to a large extent by multiple environmental factors such as temperature, drought, light availability and soil nutrients. On the molecular and biochemical levels, the expression and/or activities of fatty acid desaturases, as well as diacylglycerol acyltransferase 1, have been found to be affected by abiotic factors, suggesting that they play a role in the lipid content and compositional changes seen under abiotic stress conditions. Unfortunately, while only a very small number of strategies have been developed as of yet to minimize these environmental effects on the production of storage lipids, it is clear that this feat will be of the utmost importance for developing superior oil crops with the capability to perform in a consistent manner in field conditions in the future.

  19. Factors influencing habitat selection by arboreal pit vipers.

    PubMed

    Sawant, Nitin S; Jadhav, Trupti D

    2013-01-01

    We studied factors influencing habitat selection by two arboreal species of pit viper, namely Trimeresurus malabaricus (Malabar pit viper) and T. gramineus (Bamboo pit viper). The macrohabitat of these species was classified as forest, forest edge, or open habitat. To determine microhabitat selection, a variety of features at every other snake location were measured. Whether or not the animal was found in a tree, the tree species, its height of perch, position on the branch (distal/ apical/middle), diameter of the branch, the tree canopy (thick/sparse) and vegetation of the area (thick/sparse) were recorded. Assessment of habitat was done to determine how patterns of habitat use vary seasonally. Shaded ambient (air) temperatures and humidity were recorded. Data pertaining to 90 individuals of T. malabaricus and 100 individuals of T. gramineus were recorded. Trimeresurus malabaricus selected home ranges that included areas with thick vegetation and were encountered at regions of higher altitude. Neither of the species was found in open habitats. Both of the species preferred diverse habitats and were spread over the entire available space during the monsoon; they did not show any preference for the perch height during different seasons. Males had a positive correlation between body mass and preferred perch diameter. The present study suggests that several factors play an important role in habitat selection by these arboreal pit vipers, thus making them highly habitat-specific.

  20. [Influence of genetic factors on human sexual orientation. Review].

    PubMed

    Rodríguez-Larralde, Alvaro; Paradisi, Irene

    2009-09-01

    Human sexual orientation is a complex trait, influenced by several genes, experiential and sociocultural factors. These elements interact and produce a typical pattern of sexual orientation towards the opposite sex. Some exceptions exist, like bisexuality and homosexuality, which seem to be more frequent in males than females. Traditional methods for the genetic study of behavior multifactorial characteristics consist in detecting the presence of familial aggregation. In order to identify the importance of genetic and environmental factors in this aggregation, the concordance of the trait for monozygotic and dizygotic twins and for adopted sibs, reared together and apart, is compared. These types of studies have shown that familial aggregation is stronger for male than for female homosexuality. Based on the threshold method for multifactorial traits, and varying the frequency of homosexuality in the population between 4 and 10%, heritability estimates between 0.27 and 0.76 have been obtained. In 1993, linkage between homosexuality and chromosomal region Xq28 based on molecular approaches was reported. Nevertheless, this was not confirmed in later studies. Recently, a wide search of the genome has given significant or close to significant linkage values with regions 7q36, 8p12 and 10q26, which need to be studied more closely. Deviation in the proportion of X chromosome inactivation in mothers of homosexuals seems to favor the presence of genes related with sexual orientation in this chromosome. There is still much to be known about the genetics of human homosexuality.

  1. IMMUNOGENETIC FACTORS INFLUENCING CLINICAL COURSE OF HCV INFECTION (REVIEW).

    PubMed

    Kamkamidze, G; Butsashvili, M; Gendzekhadze, K

    2016-09-01

    Hepatitis C virus (HCV) infection remains one of the most important blood-borne diseases worldwide with about 130-170 million people chronically infected with hepatitis C virus, and more than 350 000 people die from hepatitis C-related liver diseases each year. Infection with HCV becomes chronic in approximately 80% of cases, while in up to 20% of cases hepatitis C virus is cleared from the human organism. Chronic infections of hepatitis C often leads to the end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. The clinical course and the outcome of the HCV infection is determined by the complex interplay between the viral replication and the host defense mechanisms. Several recent studies have shown that MHC class I and class II as well as natural killer (NK) cell's immunoglobulin-like receptors (KIR) loci can be associated with the HCV protection and clearance as well as with disease progression and responsiveness to antiviral treatment. Current status of our knowledge about the influence of immunogenetic factors on the clinical course of HCV infection is presented in the paper. Plans to investigate these factors among HCV infected patients enrolled in the HCV Elimination Program (launched in April 2015 in Georgia) are discussed.

  2. Identifying influencing factors on paved roads silt loading.

    PubMed

    Teng, Hualiang; Kwigizile, Valerian; James, David E; Merle, Russell

    2007-07-01

    The factors that influence the increase or decrease of silt loadings on paved roadways have not been fully quantitatively investigated. They were identified in this study based on the quarterly silt loading sampling data collected from 20 sites by the Clark County Department of Air Quality and Environmental Management in Southern Nevada for the period from 2000 to 2003. The silt loading and associated data collected over these years at one sampling site may inherently possess site-specific characteristics that can be better incorporated by using panel data models. The factors that are identified as significant are the presence of curbs and gutters, shoulder type, pavement conditions, and the presence of construction activities in the vicinity of roadways. The presence of curbs and gutters, stabilized shoulders, and good pavement conditions would result in decreased silt loadings. Conversely, the presence of construction activities within the immediate vicinity of sampled areas would result in increases of silt loadings on the roadway surfaces. Based on the analysis of the results, it was recommended that constructing curbs, gutters and stabilized shoulders, preventing or reducing construction track-out from construction activity, and improving pavement conditions be the preferred control measures to reduce silt loading on paved roadways.

  3. Factors influencing phenolic compounds in table olives (Olea europaea).

    PubMed

    Charoenprasert, Suthawan; Mitchell, Alyson

    2012-07-25

    The Mediterranean diet appears to be associated with a reduced risk of several chronic diseases including cancer and cardiovascular and Alzheimer's diseases. Olive products (mainly olive oil and table olives) are important components of the Mediterranean diet. Olives contain a range of phenolic compounds; these natural antioxidants may contribute to the prevention of these chronic conditions. Consequently, the consumption of table olives and olive oil continues to increase worldwide by health-conscious consumers. There are numerous factors that can affect the phenolics in table olives including the cultivar, degree of ripening, and, importantly, the methods used for curing and processing table olives. The predominant phenolic compound found in fresh olive is the bitter secoiridoid oleuropein. Table olive processing decreases levels of oleuropein with concomitant increases in the hydrolysis products hydroxytyrosol and tyrosol. Many of the health benefits reported for olives are thought to be associated with the levels of hydroxytyrosol. Herein the pre- and post-harvest factors influencing the phenolics in olives, debittering methods, and health benefits of phenolics in table olives are reviewed.

  4. Ecological factors influence population genetic structure of European grey wolves.

    PubMed

    Pilot, Malgorzata; Jedrzejewski, Wlodzimierz; Branicki, Wojciech; Sidorovich, Vadim E; Jedrzejewska, Bogumila; Stachura, Krystyna; Funk, Stephan M

    2006-12-01

    Although the mechanisms controlling gene flow among populations are particularly important for evolutionary processes, they are still poorly understood, especially in the case of large carnivoran mammals with extensive continuous distributions. We studied the question of factors affecting population genetic structure in the grey wolf, Canis lupus, one of the most mobile terrestrial carnivores. We analysed variability in mitochondrial DNA and 14 microsatellite loci for a sample of 643 individuals from 59 localities representing most of the continuous wolf range in Eastern Europe. We tested an array of geographical, historical and ecological factors to check whether they may explain genetic differentiation among local wolf populations. We showed that wolf populations in Eastern Europe displayed nonrandom spatial genetic structure in the absence of obvious physical barriers to movement. Neither topographic barriers nor past fragmentation could explain spatial genetic structure. However, we found that the genetic differentiation among local populations was correlated with climate, habitat types, and wolf diet composition. This result shows that ecological processes may strongly influence the amount of gene flow among populations. We suggest natal-habitat-biased dispersal as an underlying mechanism linking population ecology with population genetic structure.

  5. The Influence of Research Designs in Understanding the Control of Morphological Patterns on Bedload Path Lengths in gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Lamarre, H.; Roy, A.

    2009-05-01

    even when selecting well defined pool-bar or pool-step single entities, the morphological length scale is not associated with bedload path length in six of the seven reaches. However, in one of the reaches, a step-pool channel, the clasts did tend to move downstream from one pool to the next pool. The influence of sampling strategies was tested using the size and shape of the tagged clasts, the magnitude of the flood events, the channel characteristics, and the duration of the experiments. For some transport events, the size and the shape of the tagged clasts are both correlated with individual displacement distances. These events are not observed at specific discharge values. In general, however, the correlations are not significant. Moreover, the frequency distributions of path lengths are similar whatever the size of the tagged clasts. The percentage of mobile clasts during an initial event, as well as channel and average hydrodynamic characteristics of the streams do not affect the displacement distances or the mobility of the clasts. The duration of the experiment (from the initial seeding to the last recovery of the clasts) appears to be the only sampling factor to play a role on the significance of the relations between displacement distances and channel width, slope and bed material size. The channel morphology may affect the bedload path length but, to test this effect in the field and eventually generalize the results to different channel systems, the sampling protocol must include duration rules applied to all stream channels. This study outlines the importance standardizing research protocols for long term studies of particle path lengths.

  6. Influence of diurnal photosynthetic activity on the morphology, structure, and thermal properties of normal and waxy barley starch.

    PubMed

    Goldstein, Avi; Annor, George; Vamadevan, Varatharajan; Tetlow, Ian; Kirkensgaard, Jacob J K; Mortensen, Kell; Blennow, Andreas; Hebelstrup, Kim H; Bertoft, Eric

    2017-05-01

    This study investigated the influence of diurnal photosynthetic activity on the morphology, molecular composition, crystallinity, and gelatinization properties of normal barley starch (NBS) and waxy barley starch (WBS) granules from plants cultivated in a greenhouse under normal diurnal (16h light) or constant light photosynthetic conditions. Growth rings were observed in all starch samples regardless of lighting conditions. The size distribution of whole and debranched WBS analyzed by gel-permeation chromatography did not appear to be influenced by the different lighting regimes, however, a greater relative crystallinity measured by wide-angle X-ray scattering and greater crystalline quality as judged by differential scanning calorimetry was observed under the diurnal lighting regime. NBS cultivated under the diurnal photosynthetic lighting regime displayed lower amylose content (18.7%), and shorter amylose chains than its counterpart grown under constant light. Although the relative crystallinity of NBS was not influenced by lighting conditions, lower onset, peak, and completion gelatinization temperatures were observed in diurnally grown NBS compared to constant light conditions. It is concluded that normal barley starch is less influenced by the diurnal photosynthetic lighting regime than amylose-free barley starch suggesting a role of amylose to prevent structural disorder and increase starch granule robustness against environmental cues.

  7. Sow and litter factors influencing colostrum yield and nutritional composition.

    PubMed

    Declerck, I; Dewulf, J; Piepers, S; Decaluwé, R; Maes, D

    2015-03-01

    One of the main characteristics of colostrum intake (CI), colostrum yield (CY), and colostrum composition (CC) in pigs is its variability. The present observational study aimed to investigate factors influencing CY and CC in 10 commercial herds. In total, 100 sows of 5 different breeds and their 1,455 live-born piglets were included. Sows' CY was estimated by the CI of their suckling piglets. Colostrum composition was analyzed by LactoScope Fourier transform infrared spectroscopy. Colostrum yield averaged 3,500 ± 110 g and the percentage of colostral fat (CF), protein, and lactose in colostrum averaged 5.39 ± 0.12, 16.49 ± 0.14, and 2.02 ± 0.05 %, respectively. The effect of sow, litter, and parturition factors on CY and CC were evaluated with a linear mixed regression model with herd included as a random factor. Sows with a gestation length (GL) of 113 d had a higher CY (4,178 ± 506 g) than sows with a GL of 114 to 115 d (3,342 ± 107 g; = 0.04). An interaction was found between the litter birth weight of suckling piglets (LW) and GL ( = 0.03). In sows with a GL of 114 to 115 d, CY increased with higher LW ( = 0.009). A shorter interval between birth and first suckling of the litter was related to a higher CY ( < 0.01). The percentage of fat in colostrums was higher in Hypor sows (6.35 ± 0.51) than in PIC (4.98 ± 0.27; = 0.001), Topigs 20 (5.05 ± 0.14; < 0.001), and Danbred (5.34 ± 0.22; < 0.001) sows. The percentage of CF was negatively associated with parity ( = 0.02) and positively associated with the number of live-born piglets ( = 0.03). The percentages of colostral protein and lactose were not significantly associated with any factor in the multivariable model. In conclusion, this study demonstrated that CY and CF are affected by different sow and litter factors. Pig producers may implement these observations in their management to maximize production or reproduction potential by optimizing CI, CY, and CC.

  8. Factors influencing wood mobilization 1 in Minnesota streams

    USGS Publications Warehouse

    Merten, Eric; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

    2010-01-01

    [1] Natural pieces of wood provide a variety of ecosystem functions in streams including habitat, organic matter retention, increased hyporheic exchange and transient storage, and enhanced hydraulic and geomorphic heterogeneity. Wood mobilization is a critical process in determining the residence time of wood. We documented the characteristics and locations of 865 natural wood pieces (>0.05 m in diameter for a portion >1 m in length) in nine streams along the north shore of Lake Superior in Minnesota. We determined the locations of the pieces again after an overbank stormflow event to determine the factors that influenced mobilization of stationary wood pieces in natural streams. Seven of 11 potential predictor variables were identified with multiple logistic regression as significant to mobilization: burial, effective depth, ratio of piece length to effective stream width (length ratio), bracing, rootwad presence, downstream force ratio, and draft ratio. The final model (P< 0.001, r2 = 0.39) indicated that wood mobilization under natural conditions is a complex function of both mechanical factors (burial, length ratio, bracing, rootwad presence, draft ratio) and hydraulic factors (effective depth, downstream force ratio). If stable pieces are a goal for stream management then features such as partial burial, low effective depth, high length relative to channel width, bracing against other objects (e.g., stream banks, trees, rocks, or larger wood pieces), and rootwads are desirable. Using the model equation from this study, stewards of natural resources can better manage in-stream wood for the benefit of stream ecosystems.

  9. Factors influencing reproduction and genetic toxic effects on male gonads

    PubMed Central

    Lee, I. P.; Dixon, R. L.

    1978-01-01

    The objective of toxicological study of a target organ, such as the testis, is to elucidate the qualitative and quantitative toxic effects of a chemical on that organ. The ultimate objective is to assess the toxic effects of a chemical in laboratory animals and extrapolate the pertinent experimental data to man. To accomplish these objectives, one must consider the main factors which may influence and modulate the toxic effects of chemicals in the organ. In the male gonads, such modifying factors are the pharmacokinetic parameters governing the absorption, distribution, activation and detoxification of indirect carcinogens, covalent bindings to macromolecules, and DNA damage as well as DNA repair of damaged germ cells. All of these factors have been presently studied in our laboratory and are discussed in this paper with the exception of covalent bindings to macromolecules. The pharmacokinetic studies demonstrated that the functional blood–testis barrier (BTB) closely resembles the blood-brain barrier in transport characteristics: the permeability of nonelectrolytes and the acidic drugs with pKa values depend upon their molecular size and their partition coefficients, respectively. Thus, the functional BTB, restricts the permeability of many foreign compounds to male germ cells. Studies of mixed function oxidases and cytochrome P-450 system in male gonads demonstrated that the presence of AHH, EH, and GSH-ST implicate activation and detoxification of polycyclic hydrocarbons. Thus, active electrophiles may exert significant toxic effects locally within both interstitial and germ cell compartments. The presence of an efficient DNA repair system in premeiotic spermatogenic cells (and not in spermiogenic cells) can further modify both toxic and mutagenic events in the subsequent differentiation of germ cells to mature spermatozoa. PMID:17539139

  10. Factors influencing brown trout reproductive success in Ozark tailwater rivers

    USGS Publications Warehouse

    Pender, D.R.; Kwak, T.J.

    2002-01-01

    The reproductive success of brown trout Salmo trutta in White River, Arkansas, tailwater reaches is highly variable, resulting in the need for supplemental stocking. A better understanding of the physical and biotic factors affecting reproduction and survival would enhance the contribution of wild fish. We compared fecundity, reproductive chronology, physical habitat, water quality, trout density, food availability, diet, predation, and competitive interactions among four tailwater reaches to identify factors influencing brown trout reproductive success. The fecundity and condition factor of prespawning brown trout were significantly lower at Beaver Tailwater, a reach known for reproductive failure, than at other sites, among which no differences were found. Brown trout spawning was observed from 11 October to 23 November 1996, and juvenile emergence began on 28 February 1997. Significant among-site differences were detected for spawning and juvenile microhabitat variables, but the variables fell within or near suitable or optimal ranges reported in the literature for this species. Age-0 brown trout density differed significantly among sites, but growth and condition did not. Predation by Ozark sculpin Cottus hypselurus on trout eggs or age-0 trout of any species was not observed among the 418 stomachs examined. Ozark sculpin density and diet overlap with age-0 brown trout were highest and invertebrate food availability and water fertility were lowest at Beaver Tailwater relative to the other reaches. Our findings indicate that differences in trophic conditions occur among tailwater reaches, and a lower system productive capacity was identified at Beaver Tailwater. We suggest that management efforts include refining the multispecies trout stocking regime to improve production efficiency, enhancing flow regulation, and increasing habitat complexity to increase invertebrate and fish productivity. Such efforts may lead to improved natural reproduction and the

  11. Factors Influencing the Quality of Encapsulation in Rock Bolting

    NASA Astrophysics Data System (ADS)

    Aziz, Naj; Craig, Peter; Mirzaghorbanali, Ali; Nemcik, Jan

    2016-08-01

    Bolt installation quality is influenced by various factors, some are well known and others are less recognised. A programme of field and laboratory studies was undertaken to examine various factors of relevance to the load transfer mechanism between the bolt, resin and rock to ensure test methods truly represent field performance. Short encapsulation tests were undertaken as part of the Australian Coal Association Research Program (ACARP) funded project (C21011) with the ultimate aim of developing standard test methods for assessing bolt encapsulation with chemical resin anchor installations. The field study consisted of a series of Short Encapsulation Pull Tests (SEPT) carried out in three mines with different geological conditions to determine the most representative and practical method of SEPT. Additional field work included installation of bolts into threaded steel tubes for subsequent removal and laboratory evaluation. A series of pull tests was carried out by installing bolts in overhead rig mounted sandstone block, cast in concrete with controlled encapsulation length. Factors of importance considered included; borehole diameter, resin annulus thickness, installation time (including bolt spin to the back and "spin at back"), the effect of gloving and hole over drill. It was found that the borehole diameter had a detrimental effect on the encapsulation bonding strength. Bolt installation time of approximately 10 s constituted an acceptable time for effective bolt installation and within the resin manufacturers recommended time of 14 s. Maintaining constant length of encapsulation was paramount for obtaining consistency and repeatability of the test results. Finally, a numerical simulation study was carried out to assess the capabilities of FLAC 2D software in simulating the pull testing of rock bolts.

  12. [Influence of image process on fractal morphology characterization of NAPLs vertical fingering flow].

    PubMed

    Li, Hui-Ying; Du, Xiao-Ming; Yang, Bin; Wu, Bin; Xu, Zhu; Shi, Yi; Fang, Ji-Dun; Li, Fa-Sheng

    2013-11-01

    Dyes are frequently used to visualize fingering flow pathways, where the image process has an important role in the result analysis. The theory of fractal geometry is applied to give quantitative description of the stain patterns via image analysis, which is helpful for finger characterization and prediction. This description typically involves two parameters, a mass fractal dimension (D(m)) relative to the area, and a surface fractal dimension (D(s)) relative to the perimeter. This work detailed analyzes the influence of various choices during the thresholding step that transformed the origin color images to binary ones which are needed in the fractal analysis. One hundred and thirty images were obtained from laboratory two-dimension sand box infiltration experiments of four dyed non-aqueous phase liquids. Detailed comparisons of D(m) and D(s) were made respectively, considering a set of threshold algorithms and the filling of lakes. Results indicate that adjustments of the saturation threshold influence are less on both D(m) and D(s) in the laboratory experiments. The brightness threshold adjustments decrease the D(m) by 0.02 and increase the D(s) by 0.05. Filling lakes influence the D(m) less while the D(s) decrease by 0.10. Therefore the D(m) was recommended for further analysis to avoid subjective choices' influence in the image process.

  13. A study of the influence of a gestodene-containing triphasic oral contraceptive on endometrial morphology.

    PubMed

    Rabe, T; Leppien, G; Fossman, W G; Hessing, C; Vladescú, E; Runnebaum, B

    1997-09-01

    The objective of the study was to investigate histological changes in the endometrium in 20 volunteers treated with a low-dose, gestodene-containing triphasic oral contraceptive. Endometrial biopsy specimens were taken before, during a 6-month period of oral contraceptive use and in a post-treatment period. These specimens were evaluated using light microscopy, scanning and transmission electron microscopy. In addition, ultrasound examinations of the uterus, endometrial thickness and ovaries were performed. The low-dose, gestodene-containing triphasic oral contraceptive had no adverse effects on the endometrium (e.g. no proliferation, no polyps, no inflammatory processes), was well tolerated and showed a low side-effect profile. The inhibition of endometrial transformation was demonstrated both by endometrial morphology as well as by endometrial thickness, as measured by transvaginal ultrasound examination.

  14. Baicalin influences the dendritic morphology of newborn neurons in the hippocampus of chronically stressed rats.

    PubMed

    Jiang, Xinghua; Xu, Junmei; Zou, Dingquan; Yang, Lin; Wang, Yaping

    2013-02-25

    Chronic stress models, established in adult Sprague-Dawley rats through a 14-day subcutaneous injection of 40 mg/kg corticosterone, once per day, were given a daily oral feeding of 50 mg/kg baicalin. The study was an attempt to observe the effect of baicalin on neurogenesis in chronically stressed rats. Results showed that subcutaneous injection of corticosterone significantly decreased the total number of doublecortin-positive neurons in the hippocampus. The reduced cell number caused by corticosterone was mainly due to the decrease of class II doublecortin-positive neurons, but the class I doublecortin-positive neurons were unaffected. Baicalin treatment increased the number of both class I and class II doublecortin-positive neurons. In addition, doublecortin-positive neurons showed less complexity in dendritic morphology after corticosterone injection, and this change was totally reversed by baicalin treatment. These findings suggest that baicalin exhibits a beneficial effect on adult neurogenesis.

  15. Baicalin influences the dendritic morphology of newborn neurons in the hippocampus of chronically stressed rats☆

    PubMed Central

    Jiang, Xinghua; Xu, Junmei; Zou, Dingquan; Yang, Lin; Wang, Yaping

    2013-01-01

    Chronic stress models, established in adult Sprague-Dawley rats through a 14-day subcutaneous injection of 40 mg/kg corticosterone, once per day, were given a daily oral feeding of 50 mg/kg baicalin. The study was an attempt to observe the effect of baicalin on neurogenesis in chronically stressed rats. Results showed that subcutaneous injection of corticosterone significantly decreased the total number of doublecortin-positive neurons in the hippocampus. The reduced cell number caused by corticosterone was mainly due to the decrease of class II doublecortin-positive neurons, but the class I doublecortin-positive neurons were unaffected. Baicalin treatment increased the number of both class I and class II doublecortin-positive neurons. In addition, doublecortin-positive neurons showed less complexity in dendritic morphology after corticosterone injection, and this change was totally reversed by baicalin treatment. These findings suggest that baicalin exhibits a beneficial effect on adult neurogenesis. PMID:25206692

  16. Influence of size and morphology on the optical properties of carbon nanostructures

    NASA Astrophysics Data System (ADS)

    Sadeghi, Hajar; Dorranian, Davoud

    2016-03-01

    Optical properties of carbon nanostructures produced by laser ablation method in different liquid environments have been studied experimentally. In this work we used a 7 ns fundamental wavelength of pulsed Nd:YAG laser at 1064 nm and 10 Hz repetition rate to produce carbon nanostructures including graphene in distilled water, acetone, alcohol, and CTAB. Structure and morphology of carbon nanostructures were studied using their UV-Vis-NIR spectrum, TEM images, and Raman scattering spectrum. Results show that in our experimental condition distilled water was the most capable medium for producing graphene. Color of suspensions varied with the amount of carbon nanoparticles in the suspension while the bandgap energy of samples decreases with increasing the amount of graphene.

  17. [Emission factors of polycyclic aromatic hydrocarbons (PAHs) in residential coal combustion and its influence factors].

    PubMed

    Hai, Ting-Ting; Chen, Ying-Jun; Wang, Yan; Tian, Chong-Guo; Lin, Tian

    2013-07-01

    As the emission source of polycyclic aromatic hydrocarbons (PAHs), domestic coal combustion has attracted increasing attention in China. According to the coal maturity, combustion form and stove type associated with domestic coal combustion, a large-size, full-flow dilution tunnel and fractional sampling system was employed to collect the emissions from five coals with various maturities, which were burned in the form of raw-coal-chunk (RCC)/honeycomb-coal-briquettes (HCB) in different residential stoves, and then the emission factors of PAHs (EF(PAHs)) were achieved. The results indicate that the EF(PAHs) of bituminous coal ranged from 1.1 mg x kg(-1) to 3.9 mg x kg(-1) for RCC and 2.5 mg x kg(-1) to 21. 1 mg x kg(-1) for HCB, and the anthracite EF(PAH8) were 0.2 mg x kg(-1) for RCC and 0.6 mg x kg(-1) for HCB, respectively. Among all the influence factors of emission factors of PAHs from domestic coal combustion, the maturity of coal played a major role, the range of variance reaching 1 to 2 orders of magnitude in coals with different maturity. Followed by the form of combustion (RCC/HCB), the EF(PAHs) of HCB was 2-6 times higher than that of RCC for the same geological maturity of the coal. The type of stove had little influence on EF(PAHs).

  18. Hypobaric hypoxia in ascites resistant and susceptible broiler genetic lines influences gut morphology.

    PubMed

    de los, Santos F Solis; Tellez, G; Farnell, M B; Balog, J M; Anthony, N B; Pavlidis, H O; Donoghue, A M

    2005-09-01

    Genetic selection based on rapid growth rates, improved feed conversion, and increased body weights has led to a predisposition to ascites in broiler populations. Sire-family selection was applied to a commercial elite line to produce divergent lines of ascites-resistant (RES) and ascites-susceptible (SUS) broilers by the 8th generation. One objective of this research was to determine the effects of hypobaric hypoxia on gut morphology in these genetic lines. In two separate trials, pedigree broiler chickens were randomly assigned to cages in a hypobaric chamber (simulated 2,900 m above sea level) or a matching local altitude chamber (390 m above sea level). Ascites incidence was characterized by heart enlargement and fluid accumulation in the abdominal cavity. At the end of the study on d 42, all surviving birds were killed and evaluated for the presence of ascites and 2-cm sections from the duodenum and lower ileum were collected from 5 chickens per line, per altitude for each trial for morphometric analysis. At a high altitude, ascites incidence was lower in the RES line (20.9 and 3.7%) than in the SUS line (86.4 and 66.9%, Trials 1 and 2, respectively). No ascites was observed at a local altitude. Under hypoxic conditions, duodenum villus surface area was higher (P < 0.05) in the RES line (181.3 +/- 16.8 and 219 +/- 10.9 microm) compared with the SUS line (130.1 +/- 10.5 and 134.3 +/- 9.3 microm; Trials 1 and 2, respectively). No differences in ileum villus morphology were observed for any of the parameters measured. The reduced surface area in the duodenum of birds selected for ascites susceptibility suggests reduced enteric function and may provide clues as to why these birds have increased incidence of ascites.

  19. Genome-Wide Association Study Reveals Multiple Loci Influencing Normal Human Facial Morphology

    PubMed Central

    Raffensperger, Zachary D.; Heike, Carrie L.; Cunningham, Michael L.; Hecht, Jacqueline T.; Kau, Chung How; Moreno, Lina M.; Wehby, George L.; Murray, Jeffrey C.; Laurie, Cecelia A.; Laurie, Cathy C.; Santorico, Stephanie; Klein, Ophir; Feingold, Eleanor; Hallgrimsson, Benedikt; Spritz, Richard A.; Marazita, Mary L.; Weinberg, Seth M.

    2016-01-01

    Numerous lines of evidence point to a genetic basis for facial morphology in humans, yet little is known about how specific genetic variants relate to the phenotypic expression of many common facial features. We conducted genome-wide association meta-analyses of 20 quantitative facial measurements derived from the 3D surface images of 3118 healthy individuals of European ancestry belonging to two US cohorts. Analyses were performed on just under one million genotyped SNPs (Illumina OmniExpress+Exome v1.2 array) imputed to the 1000 Genomes reference panel (Phase 3). We observed genome-wide significant associations (p < 5 x 10−8) for cranial base width at 14q21.1 and 20q12, intercanthal width at 1p13.3 and Xq13.2, nasal width at 20p11.22, nasal ala length at 14q11.2, and upper facial depth at 11q22.1. Several genes in the associated regions are known to play roles in craniofacial development or in syndromes affecting the face: MAFB, PAX9, MIPOL1, ALX3, HDAC8, and PAX1. We also tested genotype-phenotype associations reported in two previous genome-wide studies and found evidence of replication for nasal ala length and SNPs in CACNA2D3 and PRDM16. These results provide further evidence that common variants in regions harboring genes of known craniofacial function contribute to normal variation in human facial features. Improved understanding of the genes associated with facial morphology in healthy individuals can provide insights into the pathways and mechanisms controlling normal and abnormal facial morphogenesis. PMID:27560520

  20. Influence of shell morphology on distributions of unionids in the upper Mississippi River

    USGS Publications Warehouse

    Bartsch, M.R.; Zigler, S.J.; Newton, T.J.; Sauer, J.S.

    2010-01-01

    Attempts to predict the distribution of unionids from readily measurable microhabitat descriptors (i.e. water depth, current velocity, stream size, sediment type) have been largely unsuccessful, but certain biological and calculated hydraulic variables have recently shown some predictive power. We used historic and recent data on unionids (from 1987 to 2003) and hydraulic conditions at 438 sample locations over a 38-km reach of the Upper Mississippi River (Navigation Pool 8) to compare the distribution of unionids with different shell morphologies. We evaluated whether sculptured, thick-shelled (STK) species would be found in areas with higher velocity and shear stress, compared to nonsculptured, thin-shelled (NSTN) species. We used classification trees to model the presence and absence of STK and NSTN species to determine which variables were most likely to predict their distribution. Candidate predictor variables included sampling gear, field substrate, water depth (bathymetry), slope, velocity, shear stress and Froude number under low, moderate and high discharges. Our models predicted that STK mussels would occupy a larger portion of the total aquatic area in this reach of the river than NSTN mussels. However, our data demonstrated that NSTN species used areas of higher shear stress and velocity than STK species, but were also present in backwaters with low energy, thus rejecting our hypothesis. The presence of NSTN species over a wide range of shear stress and velocity was probably due to the wide array of life histories displayed within this guild. Overall, these results are consistent with the flow refuge concept in which unionids are more prevalent in areas with low to moderate hydraulic stresses, regardless of shell morphology, and demonstrate the importance of incorporating abiotic and biotic variables into predictive models.

  1. Influence of surface morphology on the immersion mode ice nucleation efficiency of hematite particles

    SciTech Connect

    Hiranuma, N.; Hoffmann, N.; Kiselev, A.; Dreyer, A.; Zhang, K.; Kulkarni, G.; Koop, T.; Möhler, O.

    2014-01-01

    In this paper, the effect of the morphological modification of aerosol particles with respect to heterogeneous ice nucleation is comprehensively investigated for laboratory-generated hematite particles as a model substrate for atmospheric dust particles. The surface-area-scaled ice nucleation efficiencies of monodisperse cubic hematite particles and milled hematite particles were measured with a series of expansion cooling experiments using the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud simulation chamber. Complementary offline characterization of physico-chemical properties of both hematite subsets were also carried out with scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, dynamic light scattering (DLS), and an electro-kinetic particle charge detector to further constrain droplet-freezing measurements of hematite particles. Additionally, an empirical parameterization derived from our laboratory measurements was implemented in the single-column version of the Community Atmospheric Model version 5 (CAM5) to investigate the model sensitivity in simulated ice crystal number concentration on different ice nucleation efficiencies. From an experimental perspective, our results show that the immersion mode ice nucleation efficiency of milled hematite particles is almost an order of magnitude higher at -35.2 °C < T < -33.5 °C than that of the cubic hematite particles, indicating a substantial effect of morphological irregularities on immersion mode freezing. Our modeling results similarly show that the increased droplet-freezing rates of milled hematite particles lead to about one order magnitude higher ice crystal number in the upper troposphere than cubic hematite particles. Finally and overall, our results suggest that the surface irregularities and associated active sites lead to greater ice activation through droplet freezing.

  2. Effects of habitat structure on the epifaunal community in Mussismilia corals: does coral morphology influence the richness and abundance of associated crustacean fauna?

    NASA Astrophysics Data System (ADS)

    Nogueira, Marcos M.; Neves, Elizabeth; Johnsson, Rodrigo

    2015-06-01

    Coral habitat structures increase abundance and richness of organisms by providing niches, easy access to resources and refuge from predators. Corals harbor a great variety of animals; the variation in coral species morphology contributes to the heterogeneity and complexity of habitat types. In this report, we studied the richness and abundance of crustaceans (Decapoda, Copepoda, Peracarida and Ostracoda) associated with three species of Mussismilia exhibiting different growth morphologies, in two different coral reefs of the Bahia state (Caramuanas and Boipeba-Moreré, Brazil). Mussismilia hispida is a massive coral; M. braziliensis also has a massive growth pattern, but forms a crevice in the basal area of the corallum; M. harttii has a meandroid pattern. PERMANOVA analysis suggests significant differences in associated fauna richness among Mussismilia species, with higher values for M. harttii, followed by M. braziliensis and later by M. hispida. The same trend was observed for density, except that the comparison of M. braziliensis and M. hispida did not show differences. Redundancy and canonical correspondence analysis indicated that almost all of the crustacean species were more associated with the M. harttii colonies that formed a group clearly separated from colonies of M. braziliensis and M. hispida. We also found that the internal volume of interpolyp space, only present in M. harttii, was the most important factor influencing richness and abundance of all analyzed orders of crustaceans.

  3. A Phenomenological Study: The Influence of Noncognitive Factors on Academically Unprepared College Students

    ERIC Educational Resources Information Center

    Thom, Danny Moire

    2012-01-01

    This phenomenological research explored the influence of noncognitive factors in four areas: early educational factors, personal factors, affective factors, and noncognitive skill factors to understand the phenomenon of college students' academic underpreparedness. Findings related to textual categories indicated personal factors such as a…

  4. Morphology of SiO2 films as a key factor in alignment of liquid crystals with negative dielectric anisotropy

    PubMed Central

    Marino, Antigone; Otón, Eva; Bennis, Noureddine; Otón, Josè Manuel

    2016-01-01

    Control of liquid crystal (LC) orientation using a proper SiO2 alignment layer is essential for the optimization of vertically aligned nematic (VAN) displays. With this aim, we studied the optical anisotropy of thin SiO2 films by generalized ellipsometry as a function of deposition angle. The columnar SiO2 structure orientation measured by a noninvasive ellipsometry technique is reported for the first time, and its morphology influence on the LC alignment is demonstrated for large deposition angles. PMID:28144524

  5. Morphology of SiO2 films as a key factor in alignment of liquid crystals with negative dielectric anisotropy.

    PubMed

    Tkachenko, Volodymyr; Marino, Antigone; Otón, Eva; Bennis, Noureddine; Otón, Josè Manuel

    2016-01-01

    Control of liquid crystal (LC) orientation using a proper SiO2 alignment layer is essential for the optimization of vertically aligned nematic (VAN) displays. With this aim, we studied the optical anisotropy of thin SiO2 films by generalized ellipsometry as a function of deposition angle. The columnar SiO2 structure orientation measured by a noninvasive ellipsometry technique is reported for the first time, and its morphology influence on the LC alignment is demonstrated for large deposition angles.

  6. Factors influencing occupancy of nest cavities in recently burned forests

    USGS Publications Warehouse

    Saab, V.A.; Dudley, J.; Thompson, W.L.

    2004-01-01

    Recently burned forests in western North America provide nesting habitat for many species of cavity-nesting birds. However, little is understood about the time frame and the variables affecting occupancy of postfire habitats by these birds. We studied factors influencing the occupancy and reuse of nest cavities from 1-7 years after fire in two burned sites of western Idaho during 1994-1999. Tree cavities were used for nesting by 12 species of cavity nesters that were classified by the original occupant (strong excavator, weak excavator, or nonexcavator) of 385 nest cavities. We used logistic regression to model cavity occupancy by strong excavators (n = 575 trials) and weak excavators (n = 206 trials). Year after fire had the greatest influence on occupancy of nest cavities for both groups, while site of the burn was secondarily important in predicting occupancy by strong excavators and less important for weak excavators. Predicted probability of cavity occupancy was highest during the early years (1-4) after fire, declined over time (5-7 years after fire), and varied by site, with a faster decline in the smaller burned site with a greater mosaic of unburned forest. Closer proximity and greater interspersion of unburned forest (15% unburned) may have allowed a quicker recolonization by nest predators into the smaller burn compared to the larger burn with few patches of unburned forest (4% unburned). In combination with time and space effects, the predicted probability of cavity occupancy was positively affected by tree and nest heights for strong and weak excavators, respectively.

  7. Factors influencing reproductive performance of northern bobwhite in South Florida

    USGS Publications Warehouse

    Rolland, V.; Hostetler, J.A.; Hines, T.C.; Percival, H.F.; Oli, M.K.

    2011-01-01

    Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003-2008 to estimate reproductive parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10 ?? 0.22, but females laid more eggs in their first clutch (12.43 ?? 0.24) than in subsequent clutches (10.19 ?? 0.53) within a nesting season. Daily nest survival was higher for first (0.966 ?? 0.003) than subsequent nests (0.936 ?? 0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ?? 0.008, but was higher for nests incubated by females (0.873 ?? 0.009) than those incubated by males (0.798 ?? 0.018). The proportion of individuals attempting a second nest was 0.112 ?? 0.024 and 0.281 ?? 0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation. ?? 2010 Springer-Verlag.

  8. The Transcription Factor p53 Influences Microglial Activation Phenotype

    PubMed Central

    Jayadev, Suman; Nesser, Nicole K.; Hopkins, Stephanie; Myers, Scott J.; Case, Amanda; Lee, Rona J.; Seaburg, Luke A.; Uo, Takuma; Murphy, Sean P.; Morrison, Richard S.; Garden, Gwenn A.

    2011-01-01

    Several neurodegenerative diseases are influenced by the innate immune response in the central nervous system (CNS). Microglia, have pro-inflammatory and subsequently neurotoxic actions as well as anti-inflammatory functions that promote recovery and repair. Very little is known about the transcriptional control of these specific microglial behaviors. We have previously shown that in HIV associated neurocognitive disorders (HAND), the transcription factor p53 accumulates in microglia and that microglial p53 expression is required for the in vitro neurotoxicity of the HIV coat glycoprotein gp120. These findings suggested a novel function for p53 in regulating microglial activation. Here we report that in the absence of p53, microglia demonstrate a blunted response to interferon-γ, failing to increase expression of genes associated with classical macrophage activation or secrete pro-inflammatory cytokines. Microarray analysis of global gene expression profiles revealed increased expression of genes associated with anti-inflammatory functions, phagocytosis and tissue repair in p53 knockout (p53−/−) microglia compared with those cultured from strain matched p53 expressing (p53+/+) mice. We further observed that p53−/− microglia demonstrate increased phagocytic activity in vitro and expression of markers for alternative macrophage activation both in vitro and in vivo. In HAND brain tissue, the alternative activation marker CD163 was expressed in a separate subset of microglia than those demonstrating p53 accumulation. These data suggest that p53 influences microglial behavior, supporting the adoption of a pro-inflammatory phenotype, while p53 deficiency promotes phagocytosis and gene expression associated with alternative activation and anti-inflammatory functions. PMID:21598312

  9. Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

    DTIC Science & Technology

    2011-09-30

    properties of ethyl acrylate and n-butyl acrylate ( nBA )-based sulfobetaine-containing copolymers.10,11 They found that the incorporation of...ammonio]-1-propanesulfonate (SBMA), a zwitterionic mono- mer. Copolymerization of both charge-containing monomers with nBA elucidates the influence of...3-[[2-(methacryloyloxy)ethyl]- (dimethyl)ammonio]-1-propanesulfonate (SBMA), was generously provided by Raschig GmbH. n-Butyl acrylate ( nBA , Alfa

  10. Spelling patterns in preadolescents with atypical language skills: phonological, morphological, and orthographic factors.

    PubMed

    Silliman, Elaine R; Bahr, Ruth Huntley; Peters, Michelle L

    2006-01-01

    Several investigations have considered the spelling abilities of children with reading disability; however, the spelling patterns of children with a language learning disability (LLD) have been largely ignored. This study examined the spelling error patterns of three groups of children who met strict inclusion criteria-those with a known LLD (n = 8), chronological-age-matched peers (CA; n = 8), and a younger spelling-age-matched group (SA; n = 8). An experimental spelling measure was specially designed and administered to elucidate the underlying linguistic features (clusters, digraphs, etc.) and linguistic classifications (phonological, orthographical, morphological) of misspellings. Based on inferential statistical analyses, a general pattern was that the LLD group and the SA group always differed from the CA group, whereas the LLD group performed similarly to the SA group. This finding lends credence to the hypothesis that children with an LLD, like children with reading disability, are delayed in spelling development rather than following a deviant developmental process. However, a qualitative analysis indicated two specific patterns. First, the LLD group had more trouble than did the SA group in representing the basic phonological structure of words, when complexity was increased by word length or linguistic structure. Second, in contrast to the SA group, the LLD group had greater omissions of inflected and derived morphological markers. These findings point to the critical role of morphology as the mediator between and form and meaning.

  11. Hybridization in the Cetacea: widespread occurrence and associated morphological, behavioral, and ecological factors.

    PubMed

    Crossman, Carla A; Taylor, Eric B; Barrett-Lennard, Lance G

    2016-03-01

    Hybridization has been documented in a many different pairs of cetacean species both in captivity and in the wild. The widespread occurrence of hybridization indicates that postmating barriers to interbreeding are incomplete within the order Cetacea, and therefore raises questions about how species integrity is maintained in the face of interspecific (and often intergeneric) gene flow. We examined hybridization across the order Cetacea (oceanic species included: N = 78; species with 44 chromosomes included: N = 52) to test for associations between the occurrence of hybridization and similarity across 13 ecological, morphological and behavioral traits in hybridizing vs. non-hybridizing species pairs. We found that species pairs that share a greater number of traits had a higher propensity to hybridize than pairs of species that did not. This trend was driven by behavioral and morphological traits such as vocalization frequency and body size. Together our findings suggest the importance of divergent selection on morphological and behavioral traits within sympatric species in constraining opportunities for hybridization and preventing the collapse of parental species.

  12. Physico-chemical characteristics of coated silicone textured versus smooth breast implants differentially influence breast-derived fibroblast morphology and behaviour.

    PubMed

    Valencia-Lazcano, Anai A; Alonso-Rasgado, Teresa; Bayat, Ardeshir

    2014-12-01

    Capsule formation is an inevitable consequence of silicone breast implantation. Clinically challenging dense fibrocollagenous capsular contractures occur at different rates between smooth compared to textured surfaces. Host response is influenced by several factors including implant surface texture, chemistry and interactions between cells and the extracellular matrix (ECM). Specific coatings can modify the physico-chemical properties of implant surfaces eliciting specific cellular reactions. Therefore, we evaluated the physico-chemical characteristics of coated smooth versus textured silicone breast implants on breast-derived fibroblast morphology and behaviour using (a) confocal laser microscopy, (b) Raman spectroscopy and (c) the effect of four unique protein and glycosaminoglycan (GAG) coatings (aggrecan, collagen I, fibronectin and hyaluronic acid) on breast-derived fibroblast attachment, proliferation, morphology, spreading, cytotoxicity and gene expression. Collagen I, fibronectin and hyaluronic acid coatings exhibited satisfactory fibroblast adhesion (p<0.001) in comparison to uncoated surfaces. Cell adhesion was less on smooth surfaces compared to textured surfaces (p<0.001). Fibroblasts cultured on collagen I, fibronectin and hyaluronic acid coated implants demonstrated improved cell proliferation than uncoated surfaces (p<0.001). LDH assay showed that coating surfaces with collagen I, fibronectin and hyaluronic acid did not induce cytotoxicity. Alpha-actinin expression and fibroblast adhesion to the substrate were upregulated (p<0.001), in textured versus smooth surfaces. FAK, vinculin and paxillin expression were upregulated (p<0.001), in all surfaces coated with fibronectin and collagen I. In conclusion, we present original data for expression of adhesion-related genes, cell morphology and proliferation in breast fibroblasts following the application of specific coatings on breast implant surfaces.

  13. Experimental Investigation of Nascent Soot Physical Properties and The Influence on Particle Morphology and Growth

    NASA Astrophysics Data System (ADS)

    Lieb, Sydnie Marie

    Soot released to the atmosphere is a dangerous pollutant for human health and the environment. Understanding the physical properties and surface properties of these particles is important to properly explaining the growth of soot particles in flames as well as their interactions with other particles and gases in the environment. Particles below 15 nm in diameter, nascent soot particles, dominate the early growth stages of soot formation; previously these particles were characterized as hard graphitic spheres. New evidence derived from the current dissertation work, to a large extent, challenges this prior characterization. This dissertation study begins by revisiting the use of atomic force microscope (AFM) as a tool to investigate the structural properties of nascent soot. The impact of tip artifacts, which are known to complicate measurements of features below 10 nm in diameter, are carefully considered so as to provide a concise interpretation of the morphology of nascent soot as seen by AFM. The results of the AFM morphology collaborate with earlier photo- and thermal-fragmentation particle mass spectrometry and Fourier transform infrared spectroscopy that nascent soot is not a graphitized carbon material and that they are not spherical. Furthermore, phase mode imaging is introduced as a method to investigate the physical properties of nascent soot particles in a greater detail and finer resolution. The helium ion microscope (HIM) has been identified as a useful technique for the imaging of nascent soot. Using this imaging method nascent soot particles were imaged with a high resolution that had not been obtained by prior techniques. The increased contrast provides a closer look at the nascent soot particles and further suggested that these particles are not as structurally homogeneous as previously thought. Geometric shape analysis was performed to characterize the particles in terms of sphericity, circularity, and fractal dimension. The geometric analysis

  14. Factors influencing crime rates: an econometric analysis approach

    NASA Astrophysics Data System (ADS)

    Bothos, John M. A.; Thomopoulos, Stelios C. A.

    2016-05-01

    The scope of the present study is to research the dynamics that determine the commission of crimes in the US society. Our study is part of a model we are developing to understand urban crime dynamics and to enhance citizens' "perception of security" in large urban environments. The main targets of our research are to highlight dependence of crime rates on certain social and economic factors and basic elements of state anticrime policies. In conducting our research, we use as guides previous relevant studies on crime dependence, that have been performed with similar quantitative analyses in mind, regarding the dependence of crime on certain social and economic factors using statistics and econometric modelling. Our first approach consists of conceptual state space dynamic cross-sectional econometric models that incorporate a feedback loop that describes crime as a feedback process. In order to define dynamically the model variables, we use statistical analysis on crime records and on records about social and economic conditions and policing characteristics (like police force and policing results - crime arrests), to determine their influence as independent variables on crime, as the dependent variable of our model. The econometric models we apply in this first approach are an exponential log linear model and a logit model. In a second approach, we try to study the evolvement of violent crime through time in the US, independently as an autonomous social phenomenon, using autoregressive and moving average time-series econometric models. Our findings show that there are certain social and economic characteristics that affect the formation of crime rates in the US, either positively or negatively. Furthermore, the results of our time-series econometric modelling show that violent crime, viewed solely and independently as a social phenomenon, correlates with previous years crime rates and depends on the social and economic environment's conditions during previous years.

  15. Denitrification in upland of China: Magnitude and influencing factors

    NASA Astrophysics Data System (ADS)

    Wang, Jinyang; Yan, Xiaoyuan

    2016-12-01

    A better understanding of influencing factors and accurate estimate of soil denitrification is a global concern. Here we present a synthesis of 300 observations of denitrification in Chinese upland soils from 39 field and laboratory studies using the acetylene inhibition technique. The results of a linear mixed model analysis showed that the rates of soil denitrification were significantly affected by crop type, soil organic carbon, soil pH, the measurement period, and the rate of N application. The emission factor (EF) and N2O/(N2O + N2) ratio for soil denitrification were on average 2.11 ± 0.17% and 0.508 ± 0.020, respectively. Our meta-analysis indicated that N fertilization increased soil denitrification by 311% (95% CI: 279-346%) and 112% (95% CI: 66-171%) in the field and laboratory studies, respectively. Substantial interactive effects between soil properties and N fertilization on soil denitrification were found. Although the highest values of both the rate of denitrification and the EF were found in vegetable fields, the size of the stimulating effect of N fertilization on soil denitrification was lower in vegetable fields than in maize and wheat fields. These results suggest that the crop-specific effect is important and that vegetable fields are potential hot spots of denitrification in Chinese uplands. Based on either the EF or the N2O/(N2O + N2) ratio obtained, the estimated amount of total denitrification from the upland soils was an order of magnitude lower than that from budget calculations, suggesting that the acetylene inhibition technique may significantly underestimate denitrification in Chinese upland soils.

  16. Actin-myosin network influences morphological response of neuronal cells to altered osmolarity.

    PubMed

    Bober, Brian G; Love, James M; Horton, Steven M; Sitnova, Mariya; Shahamatdar, Sina; Kannan, Ajay; Shah, Sameer B

    2015-04-01

    Acute osmotic fluctuations in the brain occur during a number of clinical conditions and can result in a variety of adverse neurological symptoms. Osmotic perturbation can cause changes in the volumes of intra- and extracellular fluid and, due to the rigidity of the skull, can alter intracranial pressure thus making it difficult to analyze purely osmotic effects in vivo. The present study aims to determine the effects of changes in osmolarity on SH-SY5Y human neuroblastoma cells in vitro, and the role of the actin-myosin network in regulating this response. Cells were exposed to hyper- or hypoosmotic media and morphological and cytoskeletal responses were recorded. Hyperosmotic shock resulted in a drop in cell body volume and planar area, a persisting shape deformation, and increases in cellular translocation. Hypoosmotic shock did not significantly alter planar area, but caused a transient increase in cell body volume and an increase in cellular translocation via the development of small protrusions rich in actin. Disruption of the actin-myosin network with latrunculin and blebbistatin resulted in changes to volume and shape regulation, and a decrease in cellular translocation. In both osmotic perturbations, no apparent disruptions to cytoskeletal integrity were observed by light microscopy. Overall, because osmotically induced changes persisted even after volume regulation occurred, it is possible that osmotic stress may play a larger role in neurological dysfunction than currently believed.

  17. Differential targeting of VDAC3 mRNA isoforms influences mitochondria morphology.

    PubMed

    Michaud, Morgane; Ubrig, Elodie; Filleur, Sophie; Erhardt, Mathieu; Ephritikhine, Geneviève; Maréchal-Drouard, Laurence; Duchêne, Anne-Marie

    2014-06-17

    Intracellular targeting of mRNAs has recently emerged as a prevalent mechanism to control protein localization. For mitochondria, a cotranslational model of protein import is now proposed in parallel to the conventional posttranslational model, and mitochondrial targeting of mRNAs has been demonstrated in various organisms. Voltage-dependent anion channels (VDACs) are the most abundant proteins in the outer mitochondrial membrane and the major transport pathway for numerous metabolites. Four nucleus-encoded VDACs have been identified in Arabidopsis thaliana. Alternative cleavage and polyadenylation generate two VDAC3 mRNA isoforms differing by their 3' UTR. By using quantitative RT-PCR and in vivo mRNA visualization approaches, the two mRNA variants were shown differentially associated with mitochondria. The longest mRNA presents a 3' extension named alternative UTR (aUTR) that is necessary and sufficient to target VDAC3 mRNA to the mitochondrial surface. Moreover, aUTR is sufficient for the mitochondrial targeting of a reporter transcript, and can be used as a tool to target an unrelated mRNA to the mitochondrial surface. Finally, VDAC3-aUTR mRNA variant impacts mitochondria morphology and size, demonstrating the role of mRNA targeting in mitochondria biogenesis.

  18. Influence of the thickness on the morphology and sensing ability of thermally-deposited tellurium films

    NASA Astrophysics Data System (ADS)

    Hristova-Vasileva, T.; Bineva, I.; Dinescu, A.; Nesheva, D.; Arsova, D.; Pejova, B.

    2016-03-01

    Tellurium films with nominal thicknesses of 30, 90 and 300 nm were prepared by thermal evaporation in vacuum at a low deposition rate of 0.3 nm/s. The morphology evolution with the increase of the film thickness was observed by scanning electron microscopy and atomic force microscopy. Nanorods with a width of about 40 nm were observed on the thinnest films surface. On the 90 nm thick films, the formations grew in priority in the z-direction to nanoblades with the same width, but a length of about 100 nm. The further increase of the thickness led to an increase of the 2D nanoobjects' width and length and formation of a stacked nanosheet structure. The surface root-mean-square roughness (Sq) increased with the thickness of the films. Preliminary investigations of the sensing ability of the as-deposited tellurium films with different thicknesses towards water (H2O), ethanol (C2H5OH), acetone (C3H5OH), and ammonia (NH3) vapors were performed by measuring the vapor-induced changes in the film dark current. The films showed appreciable response only to ammonia vapors; their sensitivity was almost equal for the 30 and 90 nm thick films, and decreased significantly for the film tkness of 300 nm.

  19. Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism.

    PubMed

    Cao, Chengliang; Jiang, Jihong; Sun, Henry; Huang, Ying; Tao, Faxiang; Lian, Bin

    2016-01-01

    Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.

  20. Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism

    PubMed Central

    Cao, Chengliang; Jiang, Jihong; Sun, Henry; Huang, Ying; Tao, Faxiang; Lian, Bin

    2016-01-01

    Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments. PMID:27148166

  1. The influence of leaf morphology on litter flammability and its utility for interpreting palaeofire.

    PubMed

    Belcher, Claire M

    2016-06-05

    Studies of palaeofire rely on quantifying the abundance of fossil charcoals in sediments to estimate changes in fire activity. However, gaining an understanding of the behaviour of palaeofires is also essential if we are to determine the palaeoecological impact of wildfires. Here, I use experimental approaches to explore relationships between litter fire behaviour and leaf traits that are observable in the fossil record. Fire calorimetry was used to assess the flammability of 15 species of conifer litter and indicated that leaf morphology related to litter bulk density and fuel load that determined the duration of burning and the total energy released. These data were applied to a fossil case study that couples estimates of palaeolitter fire behaviour to charcoal-based estimates of fire activity and observations of palaeoecological changes. The case study reveals that significant changes in fire activity and behaviour likely fed back to determine ecosystem composition. This work highlights that we can recognize and measure plant traits in the fossil record that relate to fire behaviour and therefore that further research is warranted towards estimating palaeofire behaviour as it can enhance our ability to interpret the palaeoecological impact of palaeofires throughout Earth's long evolutionary history.This article is part of the themed issue 'The interaction of fire and mankind'.

  2. Factors influencing radiation therapy student clinical placement satisfaction

    SciTech Connect

    Bridge, Pete; Carmichael, Mary-Ann

    2014-02-15

    Introduction: Radiation therapy students at Queensland University of Technology (QUT) attend clinical placements at five different clinical departments with varying resources and support strategies. This study aimed to determine the relative availability and perceived importance of different factors affecting student support while on clinical placement. The purpose of the research was to inform development of future support mechanisms to enhance radiation therapy students’ experience on clinical placement. Methods: This study used anonymous Likert-style surveys to gather data from years 1 and 2 radiation therapy students from QUT and clinical educators from Queensland relating to availability and importance of support mechanisms during clinical placements in a semester. Results: The study findings demonstrated student satisfaction with clinical support and suggested that level of support on placement influenced student employment choices. Staff support was perceived as more important than physical resources; particularly access to a named mentor, a clinical educator and weekly formative feedback. Both students and educators highlighted the impact of time pressures. Conclusions: The support offered to radiation therapy students by clinical staff is more highly valued than physical resources or models of placement support. Protected time and acknowledgement of the importance of clinical education roles are both invaluable. Joint investment in mentor support by both universities and clinical departments is crucial for facilitation of effective clinical learning.

  3. Factors influencing lunchtime food choices among working Americans.

    PubMed

    Blanck, Heidi M; Yaroch, Amy L; Atienza, Audie A; Yi, Sarah L; Zhang, Jian; Mâsse, Louise C

    2009-04-01

    There is growing interest in the usefulness of the workplace as a site for promotion of healthful food choices. The authors therefore analyzed data of U.S. adults (N = 1,918) who reported working outside the home and eating lunch. The majority (84.0%) of workers had a break room. About one half (54.0%) purchased lunch > or = 2 times/week, with higher percentages for males, Blacks, younger (age 18-34 years) versus older adults (age 55 years or older), and obese versus normal-weight persons. The most important lunch food choice value was convenience (34.3%), followed by taste (27.8%), cost (20.8%), and health (17.1%). The typical source for purchasing lunch was a fast-food restaurant (43.4%), followed by on-site cafeteria/snack shop (25.3%), full-service restaurant (16.9%), supermarket (5.2%), vending machine (4.4%), and convenience store (4.0%); younger adults and those less educated relied more on fast-food places. This study identifies individual factors and values that may influence future dietary health initiatives in the work site.

  4. Factors influencing university students' explicit and implicit sexual double standards.

    PubMed

    Sakaluk, John K; Milhausen, Robin R

    2012-01-01

    Quantitative research has resulted in inconsistent evidence for the existence of a sexual double standard, leading Crawford and Popp ( 2003 ) to issue a call for methodological innovation. The implicit association test (IAT; Greenwald, McGhee, & Schwartz, 1998 ) is a measure that may provide a means to examine the double standard without the contamination of the demand characteristics and social desirability biases that plague self-report research (Marks & Fraley, 2005 ). The purpose of this study was to examine the factors influencing explicit and implicit double standards, and to examine the relationship between these explicit and implicit double standards, and levels of socially desirable responding. One hundred and three university students completed a sexual double standard IAT, an explicit measure of the double standard, and measures of socially desirable responding. Hierarchical regression analysis indicated that levels of socially desirable responding were not related to implicit or explicit double standards. Men endorsed a stronger explicit traditional double standard than women, whereas for implicit sexual standards, men demonstrated a relatively gender-neutral evaluation and women demonstrated a strong reverse double standard. These results suggest the existence of a complex double standard, and indicate that more research of sexual attitudes should include implicit measures.

  5. Factors that Influence the Effectiveness of Sanitation Programs

    PubMed Central

    Fernandez-Haddad, Marilu; Ingram, Maia

    2015-01-01

    Local governments in both Mexico and the U.S. spend considerable money on public services, which do not always bring the expected results. For instance, a large part of the public budget is destined to solve social and health problems, such as public sanitation. Government has attacked the problem by providing public sanitation infrastructure (such as garbage and recycling receptacles) and by using social ad campaigns. However, these efforts do not always affect the habits of residents and bring the desired changes in city sanitation. This article presents a case study that used a participatory method to address an innovative city sanitation effort: The Clean City Program in Puebla, Mexico. This program adopted social marketing techniques, a discipline born in the 70s when the principles and practices developed to sell products and services started to be applied to sell ideas, attitudes, or behaviors. Social marketing programs have been adopted by governments to change attitudes and behavior in areas such as public services. The article first describes the context and strategies of the program, which included the use of the promotora model to engage community members. The researchers then make use of qualitative data gathered throughout program planning and implementation to evaluate the impact of the social marketing programs and its effectiveness. The article analyzes social, educational, economic, demographic, and cultural factors that influence the effectiveness of sanitation programs and presents recommendations for strategies to engage community members in community sanitation programs. PMID:26389106

  6. Factors influencing bird foraging preferences among conspecific fruit trees

    USGS Publications Warehouse

    Foster, M.S.

    1990-01-01

    The rates at which birds visit fruiting individuals of Allophylus edulis (Sapindaceae) differ substantially among trees. Such avian feeding preferences are well-known, but usually involve fruits and trees of different species. Factors controlling avian preferences for particular trees in a population of conspecifics are generally undocumented. To address this issue, I attempted to correlate rates at which individual birds and species fed in trees of Allophylus with 27 fruit or plant characteristics. Birds that swallow fruits whole were considered separately from those that feed in other ways. Plant characters were selected on the basis of their potential influence on feeding efficiency or predation risk, assuming that birds would select feeding trees so as to maximize the net rate of energy or nutrient intake and to minimize predation. Correlations were found between feeding visits by some groups of birds and percent water in the pulp, milligrams of mineral ash in the pulp, and crop size. No character was correlated with feeding visits by all groups of birds in both years of the study. The correlations with water and mineral ash are unexplained and may be artifacts. The correlation with crop size may represent a tactic to minimize predation.

  7. Factors that Influence the Effectiveness of Sanitation Programs.

    PubMed

    Fernandez-Haddad, Marilu; Ingram, Maia

    2015-01-01

    Local governments in both Mexico and the U.S. spend considerable money on public services, which do not always bring the expected results. For instance, a large part of the public budget is destined to solve social and health problems, such as public sanitation. Government has attacked the problem by providing public sanitation infrastructure (such as garbage and recycling receptacles) and by using social ad campaigns. However, these efforts do not always affect the habits of residents and bring the desired changes in city sanitation. This article presents a case study that used a participatory method to address an innovative city sanitation effort: The Clean City Program in Puebla, Mexico. This program adopted social marketing techniques, a discipline born in the 70s when the principles and practices developed to sell products and services started to be applied to sell ideas, attitudes, or behaviors. Social marketing programs have been adopted by governments to change attitudes and behavior in areas such as public services. The article first describes the context and strategies of the program, which included the use of the promotora model to engage community members. The researchers then make use of qualitative data gathered throughout program planning and implementation to evaluate the impact of the social marketing programs and its effectiveness. The article analyzes social, educational, economic, demographic, and cultural factors that influence the effectiveness of sanitation programs and presents recommendations for strategies to engage community members in community sanitation programs.

  8. Phenotypes and enviromental factors: their influence in PCOS.

    PubMed

    Diamanti-Kandarakis, Evanthia; Christakou, Charikleia; Marinakis, Evangelos

    2012-01-01

    Polycystic ovary syndrome (PCOS) is a complex syndrome of unclear etiopathogenesis characterized by heterogeneity in phenotypic manifestations. The clinical phenotype of PCOS includes reproductive and hormonal aberrations, namely anovulation and hyperandrogenism, which coexist with metabolic disturbances. Reflecting the crosstalk between the reproductive system and metabolic tissues, obesity not only deteriorates the metabolic profile but also aggravates ovulatory dysfunction and hyperandrogenism. Although the pathogenesis of PCOS remains unclear, the syndrome appears to involve environmental and genetic components. Starting from early life and extending throughout lifecycle, environmental insults may affect susceptible women who finally demonstrate the clinical phenotype of PCOS. Diet emerges as the major environmental determinant of PCOS. Overnutrition leading to obesity is widely recognized to have an aggravating impact, while another detrimental dietary factor may be the high content of food in advanced glycated end products (AGEs). Environmental exposure to industrial products, particularly Bisphenol A (BPA), may also exacerbate the clinical course of PCOS. AGEs and BPA may act as endocrine disruptors in the pathogenesis of the syndrome. PCOS appears to mirror the harmful influence of the modern environment on the reproductive and metabolic balance of inherently predisposed individuals.

  9. Factors influencing the density of aerobic granular sludge.

    PubMed

    Winkler, M-K H; Kleerebezem, R; Strous, M; Chandran, K; van Loosdrecht, M C M

    2013-08-01

    In the present study, the factors influencing density of granular sludge particles were evaluated. Granules consist of microbes, precipitates and of extracellular polymeric substance. The volume fractions of the bacterial layers were experimentally estimated by fluorescent in situ hybridisation staining. The volume fraction occupied by precipitates was determined by computed tomography scanning. PHREEQC was used to estimate potential formation of precipitates to determine a density of the inorganic fraction. Densities of bacteria were investigated by Percoll density centrifugation. The volume fractions were then coupled with the corresponding densities and the total density of a granule was calculated. The sensitivity of the density of the entire granule on the corresponding settling velocity was evaluated by changing the volume fractions of precipitates or bacteria in a settling model. Results from granules originating from a Nereda reactor for simultaneous phosphate COD and nitrogen removal revealed that phosphate-accumulating organisms (PAOs) had a higher density than glycogen-accumulating organisms leading to significantly higher settling velocities for PAO-dominated granules explaining earlier observations of the segregation of the granular sludge bed inside reactors. The model showed that a small increase in the volume fraction of precipitates (1-5 %) strongly increased the granular density and thereby the settling velocity. For nitritation-anammox granular sludge, mainly granular diameter and not density differences are causing a segregation of the biomass in the bed.

  10. Some factors influencing salivary function when treating with radiotherapy

    SciTech Connect

    Mira, J.G.; Wescott, W.B.; Starcke, E.N.; Shannon, I.L.

    1981-04-01

    Salivary flow rate was studied in 29 patients treated with external irradiation to head and neck areas. Resting saliva samples were collected before, during the radiotherapy course and follow-up. Several parameters were investigated: field arrangement, amount of salivary glands irradiated, dose to these glands, initial FR, its recovery during and after irradiation, and influence of therapy interruption in FR. It was found that the level of the upper border of the field is a critical factor when using parallel-opposed lateral fields to the upper neck area and lateral face. More than 50% of the parotids have to be outside the fields to prevent severe dryness. Neck fields which do not encompass salivary glands do not decrease salivary secretion. There is some relation between the initial FR and the dose necessary to produce dryness: patients with high initial salivary FR require higher doses. FR recovery occurs during weekend interruptions before xerostomia develops. Interruptions of therapy for more than two weeks during the radiotherapy course prior to development of dryness might decrease late xerostomia, at least in patients with high initial FR. Objective recovery of the FR has not been observed after treatment in spite of the subjective improvement in the sensation of dryness of some patients.

  11. Factors that Influence Body Image Representations of Black Muslim Women

    PubMed Central

    2008-01-01

    Research on the body image perceptions of black women is limited. Although previous body image studies have explored the intersection between race and gender, the influence of religion has been neglected. Guided by a grounded theory framework, the focus of this investigation, conducted in Upstate New York, USA, was to examine the role of race and religion in the body image perceptions of 22 African-American Sunni Muslim women. Analysis of individual interviews revealed that, in contrast to using standard medical guidelines, participants’ views about their bodies were largely based on positive images of an earlier body size/shape, social and family expectations and contexts, cultural norms and values, and spirituality and religious beliefs. Although the body image perceptions of black Muslim women were similar to those expressed in previous body image studies with black women, participants expressed the importance of highlighting the spiritual versus physical self by adhering to religious guidelines regarding proper dress and appearance. These findings suggest that religion, race, and gender are all important factors to be considered when conducting body image studies with black women. PMID:18384923

  12. Factors Influencing Phosphorous Cycling in Biogeochemical 'Hot Spots'

    NASA Astrophysics Data System (ADS)

    Saia, S. M.; Walter, M. T.; Buda, A. R.; Carrick, H. J.; Regan, J. M.

    2015-12-01

    Anthropogenic alteration of the phosphorus (P) cycle has led to subsequent soil and water quality issues. For example, P build up in soils due to historic fertilizer application may become biologically available and exacerbate eutrophication and anoxia in nearby water bodies. In the humid Northeastern United States, storm runoff transports P and also stimulates biogeochemical processes, these locations are termed biogeochemical 'hot spots'. Many studies have looked at nitrogen and carbon cycling in biogeochemical hot spots but few have focused on P. We hypothesize the periodic wetting and drying of biogeochemical hot spots promotes a combination of abiotic and biotic processes that influence the mobility of P. To test this hypothesis, we took monthly soil samples (5 cm deep) from May to October in forest, pasture, and cropped land near Ithaca, NY. In-situ measurements taken with each sample included volumetric soil moisture and soil temperature. We also analyzed samples for 'runoff generated' phosphate, nitrate, and sulfate (from 0.01 M CaCl2 extraction), Fe(II), percent organic matter, pH, as well as oxalate extractable and total P, Al, and Fe. We used linear mixed effects models to test how runoff generated phosphate concentrations vary with soil moisture and whether other environmental factors strengthen/weaken this relationship. The knowledge gained from this study will improve our understanding of P cycling in biogeochemical hot spots and can be used to improve the effectiveness of agricultural management practices in the Northeastern United States.

  13. Preparation of Chitosan Nanoparticles: A Study of Influencing Factors

    NASA Astrophysics Data System (ADS)

    Thakur, Anupama; Taranjit

    2011-12-01

    Chitosan (CS), a cationic polysaccharide, offers great advantages for ionic interactions with negatively charged species such as sodium tripolyphosphate (STPP) leading to the formation of biocompatible crosslinked chitosan nanoparticles In the present work, an attempt has been made to systematically study the following factors influencing the ionotropic gelation of chitosan with STPP to produce CS nanoparticles: effect of pH of solution, CS concentration, STPP concentration and CS/STPP ratio. The results show that with the increase in CS concentration, the yield of the nanoparticle decreases whereas size increases. The mean size of the prepared nanoparticles varied between 120 to 720 nm and zeta potential between +14 mV to +53 mV . Nanoparticle size and yield was found to be strongly dependent on solution pH. Nanoparticle size decreased with increase in solution pH from 4 to 5 and yield was found to be maximum at pH = 5. With increase in STPP concentration, the size and yield of the nanoparticle increased. The potential of CS nanoparticles to trap amoxicillin trihydrate, taken as the model drug, was also studied. The maximum drug loading capacity was found to be 35% at a solution pH = 5 for 0.2% CS and 0.086% STPP.

  14. Study on the influence factors of camouflage target polarization detection

    NASA Astrophysics Data System (ADS)

    Huang, Yanhua; Chen, Lei; Li, Xia; Wu, Wenyuan

    2016-10-01

    The degree of linear polarization (DOLP) expressions at any polarizer direction (PD) was deduced based on the Stokes vector and Mueller matrix. The outdoors experiments were carried out to demonstrate the expressions. This paper mainly explored the DOLP-image-Contrast (DOLPC) between the target image and the background image, and the PD and RGB waveband that be considered two important influence factors were studied for camouflage target polarization detection. It was found that the DOLPC of target and background was obviously higher than intensity image. When setting the reference direction that polarizer was perpendicular to the incident face, the DOLP image of interval angle 60 degree between PD and reference direction had relatively high DOLPC, the interval angle 45 degree was the second, and the interval angle 35 degree was the third. The outdoors polarization detection experiment of controlling waveband showed that the DOLPC results was significantly different to use 650nm, 550nm and 450nm waveband, and the polarization detection performance by using 650nm band was an optimization method.

  15. Influence of Life Style Factors on Barrett's Oesophagus.

    PubMed

    Horna Strand, A; Franzén, T

    2014-01-01

    Background. Since the incidence of adenocarcinoma of the oesophagus is rising, the prognosis is poor, and surveillance programs are expensive and mostly cost ineffective, there is a need to increase the knowledge of risk factors in Barrett's oesophagus and oesophageal cancer in order to be able to give attention to medical prevention and/or surveillance programs. Aim. To study if there is a correlation between the development of Barrett's oesophagus and GOR (gastro oesophageal reflux), family history of GOR, and life style factors, such as alcohol, smoking habits, and mental stress. Methods. Fifty-five consecutively selected patients with Barrett's oesophagus (BO) examined at Linköping University Hospital's Oesophageal Laboratory were matched by sex, age, and duration of reflux symptoms with 55 GOR patients without Barrett's oesophagus at the Oesophageal Laboratory. The medical charts in respective groups were examined for comparison of life style factors, mental stress, medication, duration of gastroesophageal acid reflux at 24 hr-pH-metry, and incidence of antireflux surgery and of adenocarcinoma of the oesophagus (ACO). Also, potential gender differences and diagnosis of ACO were studied. Results. Mean percentage reflux time on 24 hr-pH-metry was higher for the Barrett's oesophagus group, 18% for women and 17% for men compared to 4% for women and 4% for men in the control group (P < 0.05). Family history of GOR was more frequent in Barrett's oesophagus patients (62%) than in the control group (35%) (P < 0.05). Male patients with Barrett's oesophagus had medical therapy for their GOR symptoms to a higher extent (38%) than male controls (65%) (P < 0.05). No difference was found in the number of tobacco users or former tobacco users between Barrett's oesophagus patients and controls. Barrett's oesophagus patients had the same level of alcohol consumption and the same average BMI as the control subjects. Female patients with Barrett's oesophagus rated

  16. Factors influencing recovery and restoration following a chemical incident.

    PubMed

    Peña-Fernández, A; Wyke, S; Brooke, N; Duarte-Davidson, R

    2014-11-01

    Chemicals are an important part of our society. A wide range of chemicals are discharged into the environment every day from residential, commercial and industrial sources. Many of these discharges do not pose a threat to public health or the environment. However, global events have shown that chemical incidents or accidents can have severe consequences on human health, the environment and society. It is important that appropriate tools and technical guidance are available to ensure that a robust and efficient approach to developing a remediation strategy is adopted. The purpose of remediation is to protect human health from future exposure and to return the affected area back to normal as soon as possible. There are a range of recovery options (techniques or methods for remediation) that are applicable to a broad range of chemicals and incidents. Recovery options should be evaluated according to their appropriateness and efficacy for removing contaminants from the environment; however economic drivers and social and political considerations often influence decision makers on which remedial actions are implemented during the recovery phase of a chemical incident. To date, there is limited information in the literature on remediation strategies and recovery options that have been implemented following a chemical incident, or how successful they have been. Additional factors that can affect the approach taken for recovery are not well assessed or understood by decision makers involved in the remediation and restoration of the environment following a chemical incident. The identification of this gap has led to the development of the UK Recovery Handbook for Chemical Incidents to provide a framework for choosing an effective recovery strategy. A compendium of practical evidence-based recovery options (techniques or methods for remediation) for inhabited areas, food production systems and water environments has also been developed and is included in the chemical

  17. Influence of solvothermal growth condition on morphological formation of hematite spheroid and pseudocubic micro structures and its magnetic coercivity

    NASA Astrophysics Data System (ADS)

    Satheesh, M.; Paloly, Abdul Rasheed; Suresh, K. G.; Junaid Bushiri, M.

    2016-11-01

    Influence of solvothermal growth condition on morphological formation and population of defects of hematite spheroid and pseudocubic micro structures and its magnetic properties were studied. Spheroid shaped crystals with different size were obtained from growth solution made of methanol, methanol-water, propanol and pseudocubic crystallites with dimension of 1.281 μm size were obtained with propanol-water solution combination at a growth temperature of 200 °C. UV absorption and magnetic properties of spheroid and pseudocubic micro structures were size and shape dependant. Spheroid shaped sample grown from precursor solution made of methanol gives intense UV absorption peaks at 360 nm and high coercivity (5.23 KOe) at room temperature. Reduction in magnetic coercivity and remanence of all samples at 5 K with respect to 300 K is attributed to antiferromagnetic nature of hematite with spheroid and pseudocubic morphology. High coercivity (6.2 KOe) at room temperature was observed from micro pseudocubic sample grown with propanol-water combination which is contributed to high aspect ratio, inter particle interaction and crystalline defects.

  18. Influence of La3+ Substitution on Structure, Morphology and Magnetic Properties of Nanocrystalline Ni-Zn Ferrite

    PubMed Central

    Dasan, Y. K.; Guan, B. H.; Zahari, M. H.; Chuan, L. K.

    2017-01-01

    Lanthanum substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5LaxFe1-xO4; 0.00 ≤x≤ 1.00) synthesized by sol-gel method were presented. X-ray diffraction patterns reveal the typical single phase spinel cubic ferrite structure, with the traces of secondary phase for lanthanum substituted nanocrystals. In addition, the structural analysis also demonstrates that the average crystallite size varied in the range of 21–25 nm. FTIR spectra present the two prominent absorption bands in the range of 400 to 600 cm-1 which are the fingerprint region of all ferrites. Surface morphology of both substituted and unsubstituted Ni-Zn ferrite nanoparticle samples was studied using FESEM technique and it indicates a significant increase in the size of spherical shaped particles with La3+ substitution. Magnetic properties of all samples were analyzed using vibrating sample magnetometer (VSM). The results revealed that saturation magnetization (Ms) and coercivity (Hc) of La3+ substituted samples has decreased as compared to the Ni-Zn ferrite samples. Hence, the observed results affirm that the lanthanum ion substitution has greatly influenced the structural, morphology and magnetic properties of Ni-Zn ferrite nanoparticles. PMID:28081257

  19. An Electrochemical NO₂ Sensor Based on Ionic Liquid: Influence of the Morphology of the Polymer Electrolyte on Sensor Sensitivity.

    PubMed

    Kuberský, Petr; Altšmíd, Jakub; Hamáček, Aleš; Nešpůrek, Stanislav; Zmeškal, Oldřich

    2015-11-11

    A systematic study was carried out to investigate the effect of ionic liquid in solid polymer electrolyte (SPE) and its layer morphology on the characteristics of an electrochemical amperometric nitrogen dioxide sensor. Five different ionic liquids were immobilized into a solid polymer electrolyte and key sensor parameters (sensitivity, response/recovery times, hysteresis and limit of detection) were characterized. The study revealed that the sensor based on 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][N(Tf)2]) showed the best sensitivity, fast response/recovery times, and low sensor response hysteresis. The working electrode, deposited from water-based carbon nanotube ink, was prepared by aerosol-jet printing technology. It was observed that the thermal treatment and crystallinity of poly(vinylidene fluoride) (PVDF) in the solid polymer electrolyte influenced the sensitivity. Picture analysis of the morphology of the SPE layer based on [EMIM][N(Tf)2] ionic liquid treated under different conditions suggests that the sensor sensitivity strongly depends on the fractal dimension of PVDF spherical objects in SPE. Their deformation, e.g., due to crowding, leads to a decrease in sensor sensitivity.

  20. Influence of growth duration on size and morphology of boron nitride nanotubes grown via chemical vapor deposition technique

    NASA Astrophysics Data System (ADS)

    Ahmad, Pervaiz; Khandaker, Mayeen Uddin; Mohd Amin, Yusoff; Raza Khan, Ziaul

    2015-10-01

    Boron nitride nanotubes are synthesized on Si substrate via a chemical vapor deposition technique with different growth durations. Field emission scanning electron microscopy micrographs show a clear influence of growth duration on size and morphology of the synthesized nanotubes. It reveals that the diameter of the tubes decreases and length increases with an increase in growth duration. Total diameter of the tube has been reduced up to 31% and length increased up to 30% with an increase of 20 min growth duration. As a result, morphology of nanotubes has also been changed from curve like to straight. Transmission electron microscope confirms the tubular structure of the synthesized nanotubes with an interlayer spacing of 0.34 nm that corresponds to d(002) plane of hexagonal boron nitride and its crystalline nature. Energy dispersive X-ray spectroscopy indicates the presence of magnesium particles in the synthesized samples that refers to its catalytic growth. X-ray photoelectron spectroscopy confirms the elemental compositions of the sample. Raman spectra reveal a peak shift of 5.48 cm-1 towards higher region of wavelength that corresponds to E2g mode of vibration in hexagonal boron nitride. This result also confirms the structural change in the synthesized boron nitride nanotubes with respect to the growth duration.

  1. Influence of La3+ Substitution on Structure, Morphology and Magnetic Properties of Nanocrystalline Ni-Zn Ferrite.

    PubMed

    Dasan, Y K; Guan, B H; Zahari, M H; Chuan, L K

    2017-01-01

    Lanthanum substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5LaxFe1-xO4; 0.00 ≤x≤ 1.00) synthesized by sol-gel method were presented. X-ray diffraction patterns reveal the typical single phase spinel cubic ferrite structure, with the traces of secondary phase for lanthanum substituted nanocrystals. In addition, the structural analysis also demonstrates that the average crystallite size varied in the range of 21-25 nm. FTIR spectra present the two prominent absorption bands in the range of 400 to 600 cm-1 which are the fingerprint region of all ferrites. Surface morphology of both substituted and unsubstituted Ni-Zn ferrite nanoparticle samples was studied using FESEM technique and it indicates a significant increase in the size of spherical shaped particles with La3+ substitution. Magnetic properties of all samples were analyzed using vibrating sample magnetometer (VSM). The results revealed that saturation magnetization (Ms) and coercivity (Hc) of La3+ substituted samples has decreased as compared to the Ni-Zn ferrite samples. Hence, the observed results affirm that the lanthanum ion substitution has greatly influenced the structural, morphology and magnetic properties of Ni-Zn ferrite nanoparticles.

  2. Influence of prenatal exposure to cimetidine and alcohol on selected morphological parameters of sexual differentiation: a preliminary report.

    PubMed

    McGivern, R F

    1987-01-01

    Pregnant rats were administered ethanol, cimetidine or a combination of both drugs from day 14 of gestation until parturition. Ano-genital (AG) distance measured at birth was significantly reduced in males exposed to cimetidine, but not in males or females exposed to alcohol. AG distance in males exposed to both ethanol and cimetidine also was not reduced, indicating a possible protective influence of ethanol against this effect of cimetidine. Birthweights in both sexes were reduced by prenatal ethanol exposure, both alone and with cimetidine exposure. Prenatal cimetidine exposure, both alone and in combination with ethanol significantly reduced seminal vesicle weights of adult males. However, no long-term effects of ethanol or cimetidine were observed on adrenal, testicular or ovarian weights. These results indicate that when fetal alcohol exposure is restricted to the critical prenatal period for hormonal actions on sexual differentiation, testosterone levels are maintained at an adequate level for normal morphological development of the genitalia.

  3. PP/EPDM-blends by dynamic vulcanization: Influence of increasing peroxide concentration on mechanical, morphological and rheological characteristics

    NASA Astrophysics Data System (ADS)

    Patermann, S.; Altstädt, V.

    2014-05-01

    Thermoplastic vulcanizates (TPVs) combine the elastic properties of thermoset cross-linked rubbers with the melt processability of thermoplastics. The most representative examples of this class are the TPVs based on polypropylene (PP) and ethylene-propylenediene terpolymer rubber (EPDM). The PP/EPDM blends were produced by dynamic vulcanization in a continuous extrusion process. The influence of different peroxide concentrations was studied with regard to cross-link density, compression set, tensile strength/elongation at break and morphology. With increasing peroxide concentration, the cross-link density increases, leading to a reduction of the compression set by 50 %. The cross-linked blends show smaller dispersed EPDM particles than the uncured one. With a peroxide concentration between 0.2 and 0.6 % a maximum in tensile strength and elongation at break was found and with increasing peroxide concentration, the complex viscosity of the TPVs decreases. Compared to batch processes, the results show nearly the same trends.

  4. SDOCT Doppler velocimetry for investigating the morphological influences on blood flow in the developing chick embryo heart

    NASA Astrophysics Data System (ADS)

    Davis, Anjul M.; Rothenberg, Florence G.; Law, Tzuo H.; Taber, Larry A.; Izatt, Joseph A.

    2007-02-01

    The onset of congenital heart disease (CHD) is believed to occur at very early stages of development. Investigations in the initiation and development of CHD has been hampered by the inability to image early stage heart structure and function, in vivo. Imaging small animals using optical coherence tomography (OCT) has filled a niche between the limited penetration depth of confocal microscopy and insufficient resolution from ultrasound. Previous demonstrations of chick heart imaging using OCT have entailed excision of, or arresting the heart to prevent motion artifacts. In this summary, we introduce SDOCT Doppler velocimetry as an enhancement of Doppler OCT for in vivo measurement of localized temporal blood flow dynamics. With this technique, dynamic velocity waveforms were measured in the outflow tract of the heart tube. These flow dynamics correlate to a finite element model of pulsatile flow and may lead to a further understanding of morphological influences on early heart development.

  5. Morphological and phase evolution of TiO 2 nanocrystals prepared from peroxotitanate complex aqueous solution: Influence of acetic acid

    NASA Astrophysics Data System (ADS)

    Chang, Jeong Ah; Vithal, Muga; Baek, In Chan; Seok, Sang Il

    2009-04-01

    Nanosized anatase and rutile TiO 2 having different shape, phase and size have been prepared from aqueous solutions of peroxo titanium complex starting from titanium(IV) isopropoxide (TTIP), acetic acid and hydrogen peroxide (H 2O 2) in water/isopropanol media by a facile sol-gel process. The TiO 2 nanocrystals are characterized by powder X-ray diffraction (XRD), Raman spectroscopy, FT-IR spectroscopy, TEM, high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) techniques. The influence of pH and the sequence of addition of reaction contents on the phase and morphology of TiO 2 are studied. The reasons for the observation of only anatase and/or mixture of anatase and rutile are given.

  6. Influence of solvent on the morphology and photocatalytic properties of ZnS decorated CeO{sub 2} nanoparticles

    SciTech Connect

    Raubach, Cristiane W. Polastro, Lisânias; Ferrer, Mateus M.; Perrin, Andre; Perrin, Christiane; Albuquerque, Anderson R.; Buzolin, Prescila G. C.; Sambrano, Julio R.; Santana, Yuri B. V. de; Varela, José A.; Longo, Elson

    2014-06-07

    Herein, we report a theoretical and experimental study on the photocatalytic activity of CeO{sub 2} ZnS, and ZnS decorated CeO{sub 2} nanoparticles prepared by a microwave-assisted solvothermal method. Theoretical models were established to analyze electron transitions primarily at the interface between CeO{sub 2} and ZnS. As observed, the particle morphology strongly influenced the photocatalytic degradation of organic dye Rhodamine B. A model was proposed to rationalize the photocatalytic behavior of the prepared decorated systems taking into account different extrinsic and intrinsic defect distributions, including order-disorder effects at interfacial and intra-facial regions, and vacancy concentration.

  7. Dietary nucleotides influence immune responses and intestinal morphology of red drum Sciaenops ocellatus.

    PubMed

    Cheng, Zhenyan; Buentello, Alejandro; Gatlin, Delbert M

    2011-01-01

    Dietary nucleotides have been shown to benefit many physiological and nutritional functions in higher vertebrates and fish. Therefore, a 6-week feeding trial was conducted to evaluate the effects of graded levels of a commercial nucleotide product on growth performance, immune responses and intestinal morphology of juvenile red drum (initial average weight of 7.1g). The basal diet was formulated to contain 40% protein, 10% lipid and a digestible energy level of 3.5 kcal g(-1). Two levels of nucleotide (Ascogen P(®), 0.5% and 1% of diet) were added to the basal diet with menhaden fishmeal and menhaden oil adjusted to provide isonitrogenous and isolipidic diets. Nucleotide supplementation tended to improve weight gain and survival of red drum, but not at a significant level. Neutrophil oxidative radical anion production and serum lysozyme activity tended to be higher for fish fed diets supplemented with nucleotide, while extracellular superoxide anion production of head kidney macrophages from fish fed diets with 1% nucleotide was significantly (P<0.05) increased, although no significant differences were observed between fish fed 0.5% nucleotide diet and the basal diet. Nucleotide supplementation significantly (P<0.05) increased fold height in the proximal intestine, and enterocyte height in the pyloric caeca, proximal and distal enteric sections. A significantly (P<0.05) higher microvilli height was observed in all evaluated enteric sections of fish fed with diets supplemented with nucleotides. It is therefore possible to use dietary nucleotides supplementation to significantly enhance the intestinal structure of red drum. Likewise, nucleotides in the diet may improve some components of the non-specific immune response of this sciaenid fish.

  8. Influence of thermal effects on the morphological patterns developed through phase separation in binary systems

    NASA Astrophysics Data System (ADS)

    Borzacchiello, D.; Leygue, A.; Chinesta, F.

    2014-07-01

    This paper is concerned with the modelling and numerical simulation of temperature-induced phase separation (TIPS) coupled with non-uniform temperature fields. The spontaneous phase separation of an initially homogeneous blend can be used, in principle, as a reliable and scalable process to reproduce specific morphologies at the microscopic scale in two-phase composite materials, such as rubber-reinforced resins, or in microstructured porous media. The size of the microstructures that are formed and the degree of anisotropy can be controlled through the imposition of an adequate temperature field. In order to understand the potential use of a temperature gradient to control phase separation, we developed a qualitative model for TIPS based on the Cahn-Hilliard approach and we proposed a computational strategy to obtain numerical solutions for phase separation in confined domains taking into account the thermal interaction with the walls. While the method is based on a volume penalization technique, the novelty of the proposed approach relies on the fact that the penalization term of the equation is constructed on the same theoretical basis from which the Cahn-Hilliard equation is derived. The advantage offered by this technique is that the same pseudo-spectral Fourier discretization schemes that are classically used to solve the Cahn-Hilliard equation in periodic domains can be straightforwardly applied to the case of bounded domains. The application examples shown in this paper emphasize the key role of the dimensionless number given by the ratio of the characteristic heat propagation time and the characteristic time of the phase separation, and demonstrate how control of the microstructure anisotropy could be achieved through TIPS.

  9. Morphological study of proximal root grooves and their influence on periodontal attachment loss

    PubMed Central

    Kaur, Saravpreet; Gupta, Rajan; Dahiya, Parveen; Kumar, Mukesh

    2016-01-01

    Background: The etiology of periodontal diseases is multifactorial including both systemic and local causes. Local factors such as grooves on root surfaces contribute a great deal to the causation of periodontal diseases. Materials and Methods: Proximal radicular grooves were studied in 150 extracted maxillary and mandibular anterior teeth. Periodontal attachment loss was measured after staining the root surfaces with 0.1% toluidine blue stain. The relationship of the presence and absence of grooves with periodontal attachment loss was also studied. Results: The prevalence of proximal root grooves was found to be 86.67%. The prevalence of grooves on maxillary teeth was 43.42% and on mandibular teeth was 56.67%. A greater loss of attachment was present on grooved surfaces than on nongrooved surfaces. Conclusion: The proximal radicular grooves present as one of the major etiological factors in periodontal diseases. PMID:27563206

  10. A Survey of the Influencing Factors for International Academic Mobility of Chinese University Students

    ERIC Educational Resources Information Center

    Cao, Chun; Zhu, Chang; Meng, Qian

    2016-01-01

    This research aims to understand the factors influencing international academic mobility within the Chinese higher education context. The inventory of University Students' Perceptions of Influencing Factors for International Academic Mobility was developed and tested to enquire about Chinese university students' perceptions of factors influencing…

  11. Parental Factors that Influence the Career Development of College-Bound African American High School Seniors

    ERIC Educational Resources Information Center

    Bostic, Shenice S.

    2010-01-01

    Parents have been identified as being the most influential factor upon their children career development. There are various factors that influence the career development of individuals from different ethnic backgrounds. The purpose of the study was to identify parental factors that influence the career development of college-bound African American…

  12. Morphological integration in the hominin dentition: evolutionary, developmental, and functional factors.

    PubMed

    Gómez-Robles, Aida; Polly, P David

    2012-04-01

    As the most common and best preserved remains in the fossil record, teeth are central to our understanding of evolution. However, many evolutionary analyses based on dental traits overlook the constraints that limit dental evolution. These constraints are diverse, ranging from developmental interactions between the individual elements of a homologous series (the whole dentition) to functional constraints related to occlusion. This study evaluates morphological integration in the hominin dentition and its effect on dental evolution in an extensive sample of Plio- and Pleistocene hominin teeth using geometric morphometrics and phylogenetic comparative methods. Results reveal that premolars and molars display significant levels of covariation; that integration is stronger in the mandibular dentition than in the maxillary dentition; and that antagonist teeth, especially first molars, are strongly integrated. Results also show an association of morphological integration and evolution. Stasis is observed in elements with strong functional and/or developmental interactions, namely in first molars. Alternatively, directional evolution (and weaker integration) occurs in the elements with marginal roles in occlusion and mastication, probably in response to other direct or indirect selective pressures. This study points to the need to reevaluate hypotheses about hominin evolution based on dental characters, given the complex scenario in which teeth evolve.

  13. Crack Healing in Quartz: Influence of Crack Morphology and pOH-

    NASA Astrophysics Data System (ADS)

    Fallon, J. A.; Kronenberg, A. K.; Popp, R. K.; Lamb, W. M.

    2004-12-01

    Crack healing in quartz has been investigated by optical microscopy and interferometry of rhombohedral r-cleavage cracks in polished Brazilian quartz prisms that were hydrothermally annealed. Quartz prisms were pre-cracked at room temperature and then annealed at temperatures T of 250° and 400° C for 2.4 to 240 hours, fluid pressure Pf = 41 MPa (equal to confining pressure Pc), and varying pOH- (from 5.4 to 1.2 at 250° C for fluids consisting of distilled water and NaOH solutions). Crack morphologies before and after annealing were recorded for each sample in plane light digital images and apertures were determined from interference fringes recorded using transmitted monochromatic light (λ = 598 nm). As documented in previous studies (Smith and Evans, 1984; Brantley et al., 1990; Beeler and Hickman, 1996), crack healing of quartz is driven by reductions in surface energy and healing rates appear to be limited by diffusional solute transport; sharply defined crack tips become blunted and break up into fluid-filled tubes and inclusions. However, fluid inclusion geometries are also observed with nonequilibrium shapes that depend on initial surface roughness. Crack healing is significant at 400° C after short run durations (24 hr) with healing rates reaching 10-5 mm/s. Crack healing is also observed at T=250° C, but only for smooth cracks with apertures < 0.6 μ m or for cracks subject to low pOH-. The extent of crack healing is sensitive to crack aperture and to hackles formed by fine-scale crack branching during crack growth. Initial crack apertures appear to be governed by the presence of fine particles, often found in the vicinity of hackles, which maintain the separation of crack surfaces. Where rough cracks exhibit healing, hackles are sites of either enhanced or reduced loss of fluid-solid interface depending on slight mismatches and sense of twist of opposing crack surfaces. Hackles of open r-cleavage cracks are replaced either by (1) healed curvilinear

  14. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (hymenoptera: bethylidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we examined the effects of biotic and abiotic factors including temperature, photoperiod, light intensity,...

  15. Mini mental state examination: influence of sociodemographic, environmental and behavioral factors and vascular risk factors.

    PubMed

    Freidl, W; Schmidt, R; Stronegger, W J; Irmler, A; Reinhart, B; Koch, M

    1996-01-01

    Age and education have been found to affect the Mini Mental State Examination (MMSE) score of elderly normals, but there have been no studies assessing the influence of environmental and behavioral factors on this test. We therefore administered the MMSE to 1437 normal elderly subjects in the setting of a stroke prevention study and correlated their results to 16 sociodemographic, environmental, and behavioral factors, and vascular risk factors. Study statistics composed of a multiple logistic regression analysis and graphical models revealed the relations between variables in greater detail. Logistic regression yielded education level, occupational status, living as a single, general life stress, physical strain, and physical inactivity to be independent predictors of the MMSE score. Age was not included in this model. Graphical models demonstrated similar results, but did not include living as a single and physical inactivity. As shown in our independence graph, general life stress is the crucial predictor and links other environmental and sociodemographic variables with the test performance of elderly normals.

  16. Factors That Influence the Difficulty of Science Words

    ERIC Educational Resources Information Center

    Cervetti, Gina N.; Hiebert, Elfrieda H.; Pearson, P. David; McClung, Nicola A.

    2015-01-01

    This study examines, within the domain of science, the characteristics of words that predict word knowledge and word learning. The authors identified a set of word characteristics--length, part of speech, polysemy, frequency, morphological frequency, domain specificity, and concreteness--that, based on earlier research, were prime candidates to…

  17. Factors influencing self-perception of health status.

    PubMed

    Kaleta, Dorota; Polańska, Kinga; Dziankowska-Zaborszczyk, Elzbieta; Hanke, Wojciech; Drygas, Wojciech

    2009-09-01

    The aim of this study was to evaluate subjective health status of Łódź adult population and to determine the factors affecting their self-perception of health. The study population consisted of randomly selected 1,056 adults aged 20-74 years from L6di district. Logistic regression model was applied to assess the factors influencing the self-perception of health. More than 30% of study subjects described their health as poor or very poor. There were no statistically significant differences between men and women regarding self-perception of health (p>0.05). Older people more frequently reported their health as poor and very poor compared to those younger than 25 years of age. Four percent of men and 10% of women younger than 25 years of age described their health as poor or very poor whereas in age category 45-54 years that percentage increased to more than 40% (men RR=16.3; p<0.001, women RR=7.5; p<0.001), in 55-64 to 60% (men RR=18.6; p<0.001, women RR=10.0; p<0.001) and for people older than 64 years of age to 60% for men (RR=12.6; p<0.01) and 72% for women (RR=13.4; p<0.001). People with lower educational degree perceived their health as worse compared to those with university diploma (men RR=5.3; p<0.001; women 4.6; p<0.001). The risk of indicating the health as poor or very poor was 3.4 times higher for unemployed men comparing to employed (p<0.001) and 1.5 for unemployed women compared to employed (p>0.05). Men indicating no leisure-time physical activity significantly more frequently described their health as poor or very poor than men with satisfactory level of recreational physical activity (RR=2.2; p<0.01). Current and former smoker men described their health as worse compared to non-smokers (current smokers RR=1.5; p>0.05; former smokers RR=1.8; p>0.05). Preventive programs aimed at improving self-perceived health should concentrate on increasing recreational physical activity and elimination of smoking. Those actions should in particular target people

  18. Peripheral blood morphologic changes after high-dose antineoplastic chemotherapy and recombinant human granulocyte colony-stimulating factor administration.

    PubMed

    Kerrigan, D P; Castillo, A; Foucar, K; Townsend, K; Neidhart, J

    1989-09-01

    The peripheral blood morphologic findings in 17 patients with cancer who had received high-dose cytotoxic chemotherapy followed by recombinant human-granulocyte colony-stimulating factor (rh-GCSF) were reviewed and compared with a control group of patients who received only high-dose chemotherapy. Both groups showed dysmyelopoiesis (abnormal granulation and nuclear lobulation) in the granulocytic series during the period of bone marrow recovery that followed the cytotoxic chemotherapy. Most of these morphologic abnormalities were more prominent in the rh-GCSF-treated group. Monocytic cells in both groups showed prominent vacuolation and immature nuclei. The percentages and absolute numbers of large granular lymphocytes were increased in the rh-GCSF group compared with the control group. No quantitative or qualitative abnormalities of eosinophilic or basophilic granulocytes were detected in either group. Both groups showed nonspecific red blood cell abnormalities, and large platelets were present in half of the control group smears. This report provides the first detailed peripheral blood morphologic description in patients treated with rh-GCSF and high-dose chemotherapy.

  19. Selection and geographic isolation influence hummingbird speciation: genetic, acoustic and morphological divergence in the wedge-tailed sabrewing (Campylopterus curvipennis)

    PubMed Central

    2011-01-01

    Background Mesoamerica is one of the most threatened biodiversity hotspots in the world, yet we are far from understanding the geologic history and the processes driving population divergence and speciation for most endemic taxa. In species with highly differentiated populations selective and/or neutral factors can induce rapid changes to traits involved in mate choice, promoting reproductive isolation between allopatric populations that can eventually lead to speciation. We present the results of genetic differentiation, and explore drift and selection effects in promoting acoustic and morphological divergence among populations of Campylopterus curvipennis, a lekking hummingbird with an extraordinary vocal variability across Mesoamerica. Results Analyses of two mitochondrial genes and ten microsatellite loci genotyped for 160 individuals revealed the presence of three lineages with no contemporary gene flow: C. c. curvipennis, C. c. excellens, and C. c. pampa disjunctly distributed in the Sierra Madre Oriental, the Tuxtlas region and the Yucatan Peninsula, respectively. Sequence mtDNA and microsatellite data were congruent with two diversification events: an old vicariance event at the Isthmus of Tehuantepec (c. 1.4 Ma), and a more recent Pleistocene split, isolating populations in the Tuxtlas region. Hummingbirds of the excellens group were larger, and those of the pampa group had shorter bills, and lineages that have been isolated the longest shared fewer syllables and differed in spectral and temporal traits of a shared syllable. Coalescent simulations showed that fixation of song types has occurred faster than expected under neutrality but the null hypothesis that morphological divergence resulted from drift was not rejected. Conclusions Our phylogeographic analyses uncovered the presence of three Mesoamerican wedge-tailed sabrewing lineages, which diverged at different time scales. These results highlight the importance of the Isthmus of Tehuantepec and more

  20. Race influences warfarin dose changes associated with genetic factors.

    PubMed

    Limdi, Nita A; Brown, Todd M; Yan, Qi; Thigpen, Jonathan L; Shendre, Aditi; Liu, Nianjun; Hill, Charles E; Arnett, Donna K; Beasley, T Mark

    2015-07-23

    Warfarin dosing algorithms adjust for race, assigning a fixed effect size to each predictor, thereby attenuating the differential effect by race. Attenuation likely occurs in both race groups but may be more pronounced in the less-represented race group. Therefore, we evaluated whether the effect of clinical (age, body surface area [BSA], chronic kidney disease [CKD], and amiodarone use) and genetic factors (CYP2C9*2, *3, *5, *6, *11, rs12777823, VKORC1, and CYP4F2) on warfarin dose differs by race using regression analyses among 1357 patients enrolled in a prospective cohort study and compared predictive ability of race-combined vs race-stratified models. Differential effect of predictors by race was assessed using predictor-race interactions in race-combined analyses. Warfarin dose was influenced by age, BSA, CKD, amiodarone use, and CYP2C9*3 and VKORC1 variants in both races, by CYP2C9*2 and CYP4F2 variants in European Americans, and by rs12777823 in African Americans. CYP2C9*2 was associated with a lower dose only among European Americans (20.6% vs 3.0%, P < .001) and rs12777823 only among African Americans (12.3% vs 2.3%, P = .006). Although VKORC1 was associated with dose decrease in both races, the proportional decrease was higher among European Americans (28.9% vs 19.9%, P = .003) compared with African Americans. Race-stratified analysis improved dose prediction in both race groups compared with race-combined analysis. We demonstrate that the effect of predictors on warfarin dose differs by race, which may explain divergent findings reported by recent warfarin pharmacogenetic trials. We recommend that warfarin dosing algorithms should be stratified by race rather than adjusted for race.