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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 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

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

    PubMed

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

    2016-01-01

    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. Phenotypic differences in a cryptic predator: factors influencing morphological variation in the terciopelo Bothrops asper (Garman, 1884; Serpentes: Viperidae).

    PubMed

    Saldarriaga-Córdoba, Mónica María; Sasa, Mahmood; Pardo, Rodrigo; Méndez, Marco Antonio

    2009-12-01

    The terciopelo Bothrops asper, is a cryptic lancehead pitviper widely distributed in humid environments of Middle America and the north-western portion of South America. Throughout its extensive distribution range, the terciopelo exhibits great morphological variation in external characters, a situation that has complicated its proper separation from other related species. In this paper, we analyzed the phenotypic variation of B. asper based in a sample of 514 specimens from nine distinct physiographic regions. Univariate and multivariate analyses demonstrated great phenotypic differentiation among most pre-established groups, and the pattern is fairly congruent between sexes. However, no correspondence was observed between morphological variation and molecular divergence, inferred from mDNA sequences, between individuals representing the physiographical regions under study. Geographic variation in the number of interrictals, ventral scales, subcaudal scales and dorsal blotches was positively correlated with latitude and number of dry months, but inversely related with precipitation. However, other variables do not exhibit such an effect. The observed relationships between scale counts and environmental variables are explained in terms of selective pressures to improve water balance along the distributional range of the species. PMID:19505490

  7. Factors controlling lava dome morphology

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan; Bridges, Nathan; Griffiths, Ross

    1991-01-01

    Research suggests that variations in lava dome morphology on different planets will depend much more critically on local gravity and the style of eruption than on the magma composition, ambient temperature, or the relative roles of convective and radiative cooling. Eruption style in turn reflects differences in tectonic conditions and the ability of magma to exsolve volatiles. Observed crude correlations between silica content and calculated yield strengths for terrestrial lava flows and domes probably are do to differences in extrusion rate and volatile solubility, rather than intrinsic rheological properties. Thus, even after taking the known effect of gravity into account, observed differences in gross dome morphology on different planets cannot by themselves be directly related to composition. Additional information such as the distribution of surface textures and structures, or spectroscopic data will be needed to conclusively establish dome compositions.

  8. 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...

  9. 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

  10. Climatic and Altitudinal Influences on Variation in Macaca Limb Morphology

    PubMed Central

    Weinstein, Karen J.

    2011-01-01

    This study compares limb lengths and joint diameters in the skeletons of six macaque species (Macaca assamensis, M. fascicularis, M. fuscata, M. mulatta, M. nemestrina, and M. thibetana) from a broad range of habitats and climates in order to test whether ambient temperatures, latitude, and altitude influence interspecific variation in limb morphology in this widely dispersed genus. Analysis of variance, principal component analysis, and partial correlation analysis reveal that species from temperate latitudes and high elevations tend to have short limbs and large joint diameters for their sizes while species from tropical latitudes and low elevations tend to have long limbs and small joint diameters. Interspecific variations in intra- and interlimb length proportions also reflect phylogeny and subtle differences in locomotion. The results of this study suggest that climatic conditions are important factors among many ecological variables that influence limb morphology in this geographically widespread genus. PMID:22567298

  11. Morphology of crystals: Internal and external controlling factors

    NASA Astrophysics Data System (ADS)

    Liu, Xiang-Yang; Bennema, P.

    1994-01-01

    Internal and external factors that influence the morphology of crystals are studied based on an inhomogeneous cell model. After discussing the reason of the failure of two basic assumptions, the equivalent wetting condition and the proportionality condition, the influence of the ambient phase is explicitly taken into account in terms of the surface characteristic scaling factor C*l. In connection with the solid-fluid interfacial structure, which is commonly determined by the crystal and the ambient phase, C*l will provide the essential information concerning how the morphology of the crystals is affected. Within the framework of our formalism, internal and external factors controlling both equilibrium forms and growth forms of crystals are described separately. This offers a guideline for the modification of the habit of crystals. To describe the morphology of crystals, the periodic bond chain analysis can be used to determine the internal controlling factors, and the interfacial structure analysis, which is developed in this paper, can be used to determine the external controlling factors. These analyses are applied to predict the growth forms of n-paraffin crystals.

  12. 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.

  13. Influence of material morphology on fabrication of large format IRFPA

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Fan, Yangyu; Si, Junjie; Wu, Wei; Hou, Zhijin

    2012-10-01

    Material characteristics of InSb wafer and Si wafer are fundamental factors to fabricating qualified infrared focal plane array (IRFPA). Parallelism and flatness of wafer are critical to yield and reliability of large format IRFPA. Influence of materials' parallelism and flatness on indium bump growing, flip-chip bonding and back thinning in the fabrication of large format IRFPA is analyzed. Parallelism of material brings additional nonuniformity to IRFPA. Parallelism after back thinning is only determined by the parallelism of readout integrated circuit (ROIC) and isn't affected by that of detector. Influence of material flatness is non-contacting or bad-contacting during flip-chip bonding, which results in bad pixels of IRFPA. According to actual fabrication condition of IRFPA, flatness of one single detector and ROIC chip should be better than 1 µm. Parallelism of ROIC chip should be better than 2 μm. Optical flat is the most convenient approach for InSb material morphology test. Utilizing higher indium bump and press in flip-chip bonding, designing larger contact metal under indium bumps or fabricating indium bumps with smaller diameter in center, selecting distribution of chips on wafer are put forward to reduce influence of morphology. Yield of large format IRFPA is improved.

  14. Morphological and chemical properties of the meadow-semidesert soil complexes of the Khaki playa (the Caspian Lowland) and the influence of the biogenic factor on them

    NASA Astrophysics Data System (ADS)

    Shabanova, N. P.; Lebedeva-Verba, M. P.; Bykov, A. V.

    2010-03-01

    The initial stage of the development of the complex soil cover pattern in the Caspian Lowland was studied. The obtained data made it possible to reveal the specific features of the morphological and chemical properties of the soils on terraces of the Khaki playa and the role of burrowing animals in the formation of the microtopography and complex soil cover patterns on the youngest surfaces. The soil cover of the studied area consists of three-component complexes: light-humus quasi-gley solonetzes on relatively flat background surfaces, zooturbated solonetzes on microhighs, and humus quasi-gley soils in microlows. The layered deposits of the Khaki playa terraces and the shallow depth of the saline groundwater are responsible for the specificity of the modern salinization of the studied solonetzes. The distribution of the salts in their profiles has a sawshaped patter, which is related to the nonuniform texture of the deposits. On the microhighs composed of the earth extracted from 5- to 7-year-old suslik burrows, specific zooturbated solonetzes are formed. The known age of these formations makes it possible to determine the rate of the desalinization of the gypsum- and salt-bearing material extracted onto the soil surface and the rate of the salt accumulation in the lower part of the solonetzic horizon and in the subsolonetzic horizons in comparison with the data on the solonetzes of the background flat surfaces. The specific features of the soils in the closed microlows suggest that these soils have a polygenetic origin. The features of the recent hydromorphism predetermine the specificity of their morphology.

  15. 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.

  16. 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,…

  17. 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.…

  18. Factors influencing dental decision making.

    PubMed

    Grembowski, D; Milgrom, P; Fiset, L

    1988-01-01

    In clinical decision making, dentists routinely choose between alternative treatments such as crown vs amalgam/composite buildup, root canal vs extraction, fixed bridge vs removable partial denture, and prophylaxis vs subgingival curettage or periodontal scaling. A number of technical and patient factors can influence dentists' choice of treatment in these situations; however, little is known about their relative importance. To address this issue, a list of technical (e.g., periodontal status and caries rate) and patient (e.g., cost and patient preference) factors possibly influencing choice of treatment was developed for each pair of services. Responding to a mail questionnaire, 156 general dentists in Washington State listed the top three factors influencing their choice of service in each pair. Results revealed that dentists took different factors into account in choosing among alternative treatments. Technical factors dominated over patient concerns; only about 33 percent of the dentists considered patient factors important in choosing alternative therapies. The latter group was less preventively oriented, were solo practitioners, worked longer hours, and had lower prices. Results suggest patients may have little influence on prescriptions of therapy among experienced general dentists. PMID:3045303

  19. 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. PMID:21063135

  20. 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 throughout the…

  1. 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 and the…

  2. 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

  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 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

  5. Role of Mechanical Factors in the Morphology of the Primate Cerebral Cortex

    PubMed Central

    Hilgetag, Claus C; Barbas, Helen

    2006-01-01

    The convoluted cortex of primates is instantly recognizable in its principal morphologic features, yet puzzling in its complex finer structure. Various hypotheses have been proposed about the mechanisms of its formation. Based on the analysis of databases of quantitative architectonic and connection data for primate prefrontal cortices, we offer support for the hypothesis that tension exerted by corticocortical connections is a significant factor in shaping the cerebral cortical landscape. Moreover, forces generated by cortical folding influence laminar morphology, and appear to have a previously unsuspected impact on cellular migration during cortical development. The evidence for a significant role of mechanical factors in cortical morphology opens the possibility of constructing computational models of cortical develoment based on physical principles. Such models are particularly relevant for understanding the relationship of cortical morphology to the connectivity of normal brains, and structurally altered brains in diseases of developmental origin, such as schizophrenia and autism. PMID:16557292

  6. Characterising natural bedform morphology and its influence on flow

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  7. The influence of fabric surface characteristics on satellite bloodstain morphology.

    PubMed

    Miles, H F; Morgan, R M; Millington, J E

    2014-07-01

    Bloodstains on fabrics such as clothing, soft furnishings or carpets are often encountered in casework. These stains often have a distinctive morphology that includes satellite stains, thought to be a highly sensitive feature that is a function of surface roughness. This study presents the findings of experimental studies conducted with proxy blood on two fabrics, similar in labeled composition, to assess the influence of fabric type on satellite stain generation. The morphology of proxy blood stains on the two fabric types were found to be statistically distinguishable from one another, with the volume of satellite stains generated being dependent upon the surface roughness of the fabric. These findings provide an initial step that illustrates the viability of providing an empirical evidence base for the interpretation of satellite stains in forensic blood pattern analysis (BPA). PMID:25002043

  8. Environmental factors influencing blackfly populations

    PubMed Central

    Carlsson, G.

    1967-01-01

    Much more information is required on the distribution of blackflies in various parts of the world, and in many cases an adequate methodology for obtaining such information still has to be worked out. A detailed methodology for the collection of information about blackflies is given, which was developed for investigations mainly in the Holarctic regions but is basically applicable to other parts of the world. A brief survey of the population dynamics of various species of blackflies in various parts of the Holarctic regions is given, and the main factors influencing the population dynamics are discussed. Interspecific and intraspecific fluctuations in natural blackfly populations are attributed chiefly to abiotic environmental factors rather than to competition. Larval competition in a given microhabitat is mainly individual, though specimens belonging to a given species may have a slightly more favourable position than others. The use of parasites and in particular the replacement of one species by another are promising methods of blackfly control. Predators are not generally likely to prove useful for this purpose. PMID:5300046

  9. Factors influencing boar sperm cryosurvival.

    PubMed

    Roca, J; Hernández, M; Carvajal, G; Vázquez, J M; Martínez, E A

    2006-10-01

    Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that

  10. [Endocrine factors influencing melanoma progression].

    PubMed

    Dobos, Judit

    2009-03-01

    According to recent findings that beside cancers traditionally considered as hormone-dependent, several other tumor types show different behavior in the two sexes, indicating the possible role of endocrine factors in the course of these diseases. The possibility that endocrine factors may influence the clinical course of human malignant melanoma is suggested by the higher survival rate in premenopausal vs. postmenopausal women or men of any ages. However, investigations on the sex hormone receptor status of human cutaneous melanomas and experiments attempting to support the epidemiological results yielded conflicting results. In our human melanoma cell lines we failed to detect steroid receptors at protein level, while quantitative PCR demonstrated that their mRNA expression level was orders of magnitude lower compared to the positive control cell lines. Sex hormones did not influence the in vitro features of the human melanoma cells considerably. On the other hand, glucocorticoid receptor was present both at mRNA and protein level, although dexamethasone was effective in vitro only at high doses. Our previous experiments showed that intrasplenic injection of human melanoma cells resulted in a significantly higher number of liver colonies in male than in female SCID mice. We now show that this difference evolves during the first day. After injection into the tail vein we did not observe gender-dependent difference in the efficiency of pulmonary colonization. Examining the pattern of metastasis formation after intracardiac injection, we have found differences between the two sexes in the incidence or number of colonies only in the case of the liver but not in other organs. We concluded that the observed phenomenon is specific to the liver; therefore we investigated the effects of 2-methoxyestradiol, an endogenous metabolite of estradiol produced mainly in the liver, with an estrogen receptor-independent antitumor activity. 2ME2 effectively inhibited melanoma cell

  11. Neuron Morphology Influences Axon Initial Segment Plasticity123

    PubMed Central

    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. PMID:27022619

  12. Influence Of Sterilization On Bulk And Surface Morphologies Of Copolyether-Urethane-Ureas

    NASA Astrophysics Data System (ADS)

    Knutson, K.; Lyman, D. J.

    1981-10-01

    The influence of sterilization on the bulk and surface morphologies of a copolyether-urethane-urea was studied. The bulk morphology was altered due to annealing by autoclaving and ethylene oxide sterilization. Radiation sterilization did not significantly alter the morphology. Surface morphology was not significantly altered by any of the sterilization procedures. Changes in chemical structure as the result of sterilization were not observed.

  13. Ring Current Morphology and the Influence of FACs

    NASA Astrophysics Data System (ADS)

    Dunlop, M. W.; Bogdanova, Y.; Shen, C.; Zhang, Q.; Luhr, H.; Yang, Y.; Dandouras, I. S.; Mccullough, C.; Perry, C. H.; Ritter, P.; Rong, Z.; Taylor, M. G.; Fazakerley, A. N.

    2013-12-01

    The imminent launch of the 3 Swarm spacecraft into low, polar Earth orbits; the planned coordination of Swarm with the 4 Cluster spacecraft through joint operations, and the further possible coordination with the recently launched 2 spacecraft RBSP spacecraft, provides an unprecedented, distributed space dataset of 'clustered' multi-point measurements. In anticipation of the direct comparison of Swarm and Cluster, preliminary study of the morphology and influence of the ring current using Cluster has produced a full-circle determination of the in-situ RC and associated FACs directly from the 4-spacecraft perigee observations. Such externally induced magnetic signals have significant effect at low Earth orbit (LEO) so that coordinated measurements of the current systems from ground to the (inner) magnetosphere are highly desirable and may be used to validate the Swarm constellation data. We report here further investigations of the RC morphology and compare the significance of the connecting FACs and partial eastward current using analysis techniques derived from the calculation of curl B and magnetic gradients. We also investigate the consequences for future spacecraft constellations at both Cluster and Swarm, during potential joint operations.

  14. The antioxidant protein Oxr1 influences aspects of mitochondrial morphology.

    PubMed

    Wu, Yixing; Davies, Kay E; Oliver, Peter L

    2016-06-01

    Oxidative stress (OS) and mitochondrial dysfunction are implicated in neurodegenerative disease, suggesting that antioxidant defence systems are critical for cell survival in the central nervous system (CNS). Oxidation resistance 1 (OXR1) can protect against OS in cellular and mouse models of amyotrophic lateral sclerosis (ALS) when over-expressed, whereas deletion of Oxr1 in mice causes neurodegeneration. OXR1 has emerged therefore as an essential antioxidant protein that controls the susceptibility of neurons to OS. It has been suggested that OXR1 is localised to mitochondria, yet the functional significance of this has not been investigated in the context of neuronal cell death. In order to characterise the role of Oxr1 in mitochondria, we investigated its sub-mitochondrial localisation and demonstrate that specific isoforms are associated with the outer mitochondrial membrane, while the full-length Oxr1 protein is predominately cytoplasmic. Interestingly, cytoplamsic over-expression of these mitochondrially-localised isoforms was still able to protect against OS-induced cell death and prevent rotenone-induced mitochondrial morphological changes. To study the consequences of Oxr1 deletion in vivo, we utilised the bella ataxic mouse mutant. We were unable to identify defects in mitochondrial metabolism in primary cerebellar granule cells (GCs) from bella mice, however a reduction in mitochondrial length was observed in mutant GCs compared to those from wild-type. Furthermore, screening a panel of proteins that regulate mitochondrial morphology in bella GCs revealed de-regulation of phospho-Drp1(Ser616), a key mitochondrial fission regulatory factor. Our data provide new insights into the function of Oxr1, revealing that specific isoforms of this novel antioxidant protein are associated with mitochondria and that the modulation of mitochondrial morphology may be an important feature of its protective function. These results have important implications for the

  15. 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…

  16. Urban Morphology Influence on Urban Albedo: A Revisit with the S olene Model

    NASA Astrophysics Data System (ADS)

    Groleau, Dominique; Mestayer, Patrice G.

    2013-05-01

    This heuristic study of the urban morphology influence on urban albedo is based on some 3,500 simulations with the S olene model. The studied configurations include square blocks in regular and staggered rows, rectangular blocks with different street widths, cross-shaped blocks, infinite street canyons and several actual districts in Marseilles, Toulouse and Nantes, France. The scanned variables are plan density, facade density, building height, layout orientation, latitude, date and time of the day. The sky-view factors of the ground and canopy surfaces are also considered. This study demonstrates the significance of the facade density, in addition to the built plan density, as the explanatory geometrical factor to characterize the urban morphology, rather than building height. On the basis of these albedo calculations the puzzling results of Kondo et al. (Boundary-Layer Meteorol 100:225-242, 2001) for the influence of building height are explained, and the plan density influence is quantitatively assessed. It is shown that the albedo relationship with plan and facade densities obtained with the regular square plot configuration may be considered as a reference for all other configurations, with the exception of the infinite street canyon that shows systematic differences for the lower plan densities. The curves representing this empirical relationship may be used as a sort of abacus for all other geometries while an approximate simple mathematical model is proposed, as well as relationships between the albedo and sky-view factors.

  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 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.

  19. Genetic factors influencing alcohol dependence

    PubMed Central

    Mayfield, R D; Harris, R A; Schuckit, M A

    2008-01-01

    Plentiful data from both animal and human studies support the importance of genetic influences in substance abuse and dependence (Bierut et al., 1998; Tsuang et al., 1998; Kendler et al., 2003). This review summarizes the evidence supporting such genetic influences, places them into perspective regarding animal and human studies, discusses the importance of both genes and environment, and highlights some specific genes of interest regarding the vulnerabilities for problems associated with alcohol use disorders. A long history of repetitive heavy use of alcohol exists across generations as well as the high prevalence of alcohol-related problems in Western societies. Moreover, the information offered here addresses the importance of more general issues regarding genetics and gene expression related to alcohol abuse and dependence. PMID:18362899

  20. Influence of Selective Biochemical and Morphological Agents on Natural History of Aneurysm of Abdominal Aorta Development.

    PubMed

    Wołoszko, Tomasz; Skórski, Maciej; Kwasiborski, Przemysław; Kmin, Ewelina; Gałązka, Zbigniew; Pogorzelski, Ryszard

    2016-01-01

    BACKGROUND The development of abdominal aortic aneurysm (AAA) is probably influenced by many factors. The role of some of these factors, such as intraluminal thrombus (ILT) or cystatin C serum levels, remains controversial. Proving their influence could have therapeutic implications for some patients with AAA. Associations between the rate of increase in diameter of an aneurysm and ILT, as well as other factors, including biochemical factors (C-Reactive Protein - CRP, cystatin C), age, sex, and comorbidities, could predict disease progression in individual patients. MATERIAL AND METHODS Seventy patients with small AAA were included into the study. The patients were followed using ultrasound and CT imaging. We evaluated aneurysm dimensions and aneurysm wall thickness, as well as ILT and its dimensions, aneurysm wall morphology, CRP, and cystatin C. RESULTS We observed significant growth of AAA and thinning of aneurysmal wall. Aneurysms over 4 cm grew significantly faster in the second year of observation. ILT grew together with AAA size. Age, sex, smoking, dyslipidemias, or controlled arterial hypertension had no influence on aneurysm progression rate. Changes in serum of CRP concentration did not reach statistical significance, but cystatin C levels did. CONCLUSIONS Presence and size of ILT, wall thickness, and cystatin C levels may be considered in prediction of AAA progression. ILT might exert a protective influence on the risk of aneurysm rupture. However, larger aneurysms containing larger thrombi grow faster and their walls undergo more rapid degradation, which in turn increases the risk of rupture. This matter requires further studies. PMID:26859744

  1. The Environmental Factors Influencing Attrition.

    ERIC Educational Resources Information Center

    Villella, Edward F.

    1986-01-01

    Offers an economics/business-management perspective on student attrition, focusing on the external macro-environment (including such factors as government funding of education, changing enrollment patterns, and the increased number of postsecondary institutions) and the internal micro-environment (exhibiting characteristics of intangibility,…

  2. 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. PMID:27561516

  3. 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).

  4. 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

  5. Morphological specialization influences nectar extraction efficiency of sympatric nectar-feeding bats.

    PubMed

    Gonzalez-Terrazas, Tania P; Medellin, Rodrigo A; Knörnschild, Mirjam; Tschapka, Marco

    2012-11-15

    Mammals frequently use nectar as a supplementary food, while a predominantly nectarivorous lifestyle with morphological specializations for this feeding mode is rare within the class. However, Neotropical flower-visiting bats largely depend on nectar resources and show distinct adaptations to a nectar diet. Glossophagine bats form local guilds of 2-6 species that may differ distinctly in skull morphology. It is still unknown how and to what extent this morphological diversity influences the efficiency of nectar extraction and hence resource partitioning within the local bat guild. As foraging behaviour is a key factor for niche partitioning of co-existing species, we compared nectar extraction behaviour and efficiency at different flower depths among sympatric bat species with different degrees of morphological specialization (Glossophaga soricina, Leptonycteris yerbabuenae and Musonycteris harrisoni). In flight cage experiments with artificial flowers, at deeper nectar levels all species showed a distinct decrease in the amount of nectar extracted per visit and an increase in the time spent hovering at the flower, indicating increased energetic cost when foraging on longer tubed flowers. The lowest nectar extraction efficiency (g s(-1)) was found in the small G. soricina and the highest in the largest species L. yerbabuenae. However, when also considering the different energy requirements of the different-sized bat species, the morphologically most specialized M. harrisoni consistently showed the highest foraging efficiency. Our data suggest that the long rostrum and tongue of the extremely specialized M. harrisoni are probably not evolved for monopolization of co-evolved deep flowers but for allowing efficient access to the broadest range of the local chiropterophilous flower resources. PMID:22899529

  6. 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. PMID:26479727

  7. Factors potentially influencing aminoglycoside use and expenditure

    SciTech Connect

    DiPiro, J.T.; Kilsdonk, G.F.; Amerson, A.B.; Record, K.E.

    1982-07-01

    Factors that may have influenced aminoglycoside use and expenditure in one hospital were examined. Factors that were evaluated as to their influence on aminoglycoside-use patterns were: (1) formulary status; (2) bacterial susceptibility patterns; (3) identified or perceived differences in toxicity; (4) changes in patient population; (5) price paid by the hospital for aminoglycosides; (6) distribution of newsletters or memoranda; (7) advertising and detailing; and (8) pharmacy policies. For FY 1976-77 to 1979-80, the largest proportion of aminoglycoside expense was for gentamicin. During FY 1980-81, the expenditure for gentamicin decreased and tobramycin accounted for the largest proportion of total expenditure. Monthly gentamicin use decreased 20% during FY 1980-81 from the previous year. Tobramycin use increased from January 1979 to November 1980 and decreased from December 1980 to June 1981. Kanamycin use and amikacin use were fairly constant during the study period. Based on temporal relationships, the following factors appeared to influence aminoglycoside use and expenditure: (1) a study conducted at the institution from June 1977 to June 1979 comparing gentamicin and tobramycin nephrotoxicity; (2) a comparative nephrotoxicity study published in a widely circulated medical journal in May 1980; and (3) an intramural newsletter and memorandum distributed in March 1981 encouraging selective aminoglycoside use. The identification of factors that potentially influenced aminoglycoside use can be used to anticipate the future impact of similar events and to devise strategies to influence antimicrobial use.

  8. Influence of monosaccharides and related molecules on the morphology of hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Walsh, Dominic; Kingston, Joanne L.; Heywood, Brigid R.; Mann, Stephen

    1993-10-01

    The influence of monosaccharides and related molecules on the crystal morphology of hydroxyapatite (HAP) precipitated from chloride-containing supersaturated solutions has been studied by transmission electron microscopy. Pulse addition of aliquots of CaCl 2 to Na 2HPO 4 solutions resulted in the formation of plate-like HAP crystals. In contrast, the presence of the monosaccharides D-glucose, D-galactose, D-mannose, glucuronic acid, N-acetyl glucosamine and D-fructose (phosphate:additive = 6:1) induced the precipitation of needle-shaped HAP crystals elongated along the c-axis. Other molecules, such as sorbitol and 1,2-butanediol, also showed this morphological effect. The order of decreasing aspect ratios was; sorbitol = 1,2-butanediol (25:1)> fructose (20:1)> glucose = galactose = mannose = glucuronic acid = N-acetyl glucosamine (10:1). Expression of the needle-like morphology is discussed in terms of kinetic factors involving nucleation and growth. The former is dependent on the exclusion of Cl - from HAP nuclei due to additive interactions with an amorphous calcium phosphate precursor phase. The latter is related to the strength of additive binding with the subsequent development of {100} HAP crystal faces.

  9. Factors Influencing the Fatigue Strength of Materials

    NASA Technical Reports Server (NTRS)

    Bollenrath, F

    1941-01-01

    A number of factors are considered which influence the static and fatigue strength of materials under practical operating conditions as contrasted with the relations obtaining under conditions of the usual testing procedure. Such factors are interruptions in operation, periodically fluctuating stress limits and mean stresses with periodic succession of several groups and stress states, statistical changes and succession of stress limits and mean stresses, frictional corrosion at junctures, and notch effects.

  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. 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. PMID:25295734

  12. Technology Education Graduate Education: Factors Influencing Participation.

    ERIC Educational Resources Information Center

    Cardon, Phillip L.; Rogers, George E.

    A modified Delphi technique was used to identify the factors that positively influence technology education teachers' decision to enroll in graduate education programs and the barriers to their enrollment in advanced degree programs. Two pairs of Delphi panels were established. The doctoral panels consisted of 15 recent doctoral graduates and 30…

  13. Factors Influencing Learning at a Community College.

    ERIC Educational Resources Information Center

    Johnson, Marvin L.

    The Walberg Educational Productivity Model theorizes that learning in its affective, behavioral, and cognitive aspects is causally influenced by factors in the areas of individual aptitude (i.e., prior achievement, age or stage of maturation, and motivation), instructional treatment (i.e., quantity of time spent in learning situations and…

  14. Factors Influencing the Successful Introduction of Portfolios

    ERIC Educational Resources Information Center

    Van Tartwijk, Jan; Driessen, Erik; Van Der Vleuten, Cees; Stokking, Karel

    2007-01-01

    Factors influencing the successful introduction of portfolios are described. A portfolio is a purposeful collection of all kinds of documents and other artefacts that together give an impression of how tasks were fulfilled and how competence has developed. A portfolio can also contain reflections and plans for future development. Although…

  15. 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…

  16. 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…

  17. Factors Influencing Teaching Choice in Turkey

    ERIC Educational Resources Information Center

    Kilinc, Ahmet; Watt, Helen M. G.; Richardson, Paul W.

    2012-01-01

    Why choose to become a teacher in Turkey? The authors examined motivations and perceptions among preservice teachers (N = 1577) encompassing early childhood, primary and secondary education. The Factors Influencing Teaching Choice (FIT-Choice) instrument was translated into Turkish and its construct validity and reliability assessed. Altruistic…

  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. 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

  20. 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.

  1. Factors Influencing Seminar Learning and Academic Achievement.

    PubMed

    Spruijt, Annemarie; Leppink, Jimmie; Wolfhagen, Ineke; Bok, Harold; Mainhard, Tim; Scherpbier, Albert; van Beukelen, Peter; Jaarsma, Debbie

    2015-01-01

    Many veterinary curricula use seminars, interactive educational group formats in which some 25 students discuss questions and issues relating to course themes. To get indications on how to optimize the seminar learning process for students, we aimed to investigate relationships between factors that seem to be important for the seminar learning process, and to determine how these seminar factors account for differences in students' achievement scores. A 57-item seminar evaluation (USEME) questionnaire was administered to students right after they attended a seminar. In total, 80 seminars distributed over years 1, 2, and 3 of an undergraduate veterinary medicine curriculum were sampled and 988 questionnaires were handed in. Principal factor analysis (PFA) was conducted on 410 questionnaires to examine which items could be grouped together as indicators of the same factor, and to determine correlations between the derived factors. Multilevel regression analysis was performed to explore the effects of these seminar factors and students' prior achievement scores on students' achievement scores. Within the questionnaire, four factors were identified that influence the seminar learning process: teacher performance, seminar content, student preparation, and opportunities for interaction within seminars. Strong correlations were found between teacher performance, seminar content, and group interaction. Prior achievement scores and, to a much lesser extent, the seminar factor group interaction appeared to account for differences in students' achievement scores. The factors resulting from the present study and their relation to the method of assessment should be examined further, for example, in an experimental setup. PMID:26075625

  2. 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.

  3. 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. PMID:8324609

  4. 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

  5. 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

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

    PubMed

    Campbell, Diane R; Powers, John M

    2015-06-01

    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. 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

  8. 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…

  9. Influence of surface laser cleaning combined with substrate preheating on the splat morphology

    NASA Astrophysics Data System (ADS)

    Costil, S.; Liao, H.; Gammoudi, A.; Coddet, C.

    2005-03-01

    The morphology of sprayed splats influences the coating adhesion and properties, which are determined by the spraying parameters. Many studies in this field show that the substrate surface temperature is a very relevant factor for the splat shape: the hypotheses of substrate surface wettability and contamination or adsorption layer on the surfaces are supported by the fact that the near-disk-shaped splat can be obtained by increasing the substrate temperature. In this work, a short-duration pulsed laser was used to ablate the substrate just before powder spraying. This ablation was powerful enough to eliminate the contaminants on the substrate surface and to improve the adhesion. In this study the analyses of NiAl splat morphology on the polished TA6V (Ti-6Al-4V) substrate were carried out using laser ablation with different substrate temperatures and different heating modes: the flame and another laser. Results show that the temperature at which the disk-shaped splat can be obtained decreased dramatically by laser ablation. Moreover, laser ablation combined with another laser increased the adhesion strength of the coatings.

  10. Postpartum cervical repair in mice: a morphological characterization and potential role for angiogenic factors.

    PubMed

    Stanley, Robert; Ohashi, Takako; Mowa, Chishimba

    2015-10-01

    The cervix undergoes marked mechanical trauma during delivery of the baby at birth. As such, a timely and complete tissue repair postpartum is necessary to prevent obstetrical complications, such as cervicitis, ectropion, hemorrhage, repeated miscarriages or abortions and possibly preterm labor and malignancies. However, our knowledge of normal cervical repair is currently incomplete and factors that influence repair are unclear. Here, we characterize the morphological and angiogenic profile of postpartum repair in mice cervix during the first 48 h of postpartum. The key findings presented here are: (1) cervical epithelial folds and size are diminished during the first 48 h of postpartum repair, (2) hypoxic inducible factor 1a, vascular endothelial growth factor (VEGF), and VEGF receptor 1 expression are pronounced early in postpartum cervical repair, and (3) VEGF receptor 2 gene and protein expressions are variable. We conclude that postpartum cervical repair involves gross and microscopic changes and is linked to expression of angiogenic factors. Future studies will assess the suitability of these factors, identified in the present study, as potential markers for determining the phase of postpartum cervical repair in obstetrical complications, such as cervical lacerations. PMID:25943091

  11. Landscape characteristics influence morphological and genetic differentiation in a widespread raptor (Buteo jamaicensis).

    PubMed

    Hull, Joshua M; Hull, Angus C; Sacks, Benjamin N; Smith, Jeff P; Ernest, Holly B

    2008-02-01

    Landscape-scale population genetic structure in vagile vertebrates was commonly considered to be a contradiction in terms whereas recent studies have demonstrated behaviour and habitat associated structure in several such species. We investigate whether landscape features influence morphological and genetic differentiation in a widespread, mobile raptor. To accurately describe genetic differentiation associated with regional landscape factors, we first investigated subspecies relationships at a continental scale. We used 17 microsatellite loci and five morphological measurements to investigate differentiation between eastern and western subspecies of red-tailed hawks (Buteo jamaicensis) and to identify patterns between differentiation and habitat within western North America. Bayesian and frequency-based analyses of microsatellite data revealed clear distinctions between B. j. borealis (eastern) and B. j. calurus (western) samples. Furthermore, hawks sampled in Texas were stouter than those collected from the Rocky Mountains and farther west. Among western samples, birds from the Great Basin, Rocky Mountains, and Washington were significantly different in morphology than those from Oregon and California. We identified a pattern of isolation by distance among western breeding sites around the Sierra Nevada. Given the long-range dispersal capabilities of raptors, this pattern suggests that population-specific habitat preferences, corresponding with habitat breaks between eastern and western slopes of the Sierra Nevada, and/or regionally variable population densities limit migration between the Mediterranean habitat of central California and the xeric habitats of southern California and interior west. We suggest habitat preferences and regionally disparate population densities may play a role in shaping genetic structure in vagile avian taxa. PMID:18208488

  12. Factors influencing union formation in Nairobi, Kenya.

    PubMed

    Bocquier, Philippe; Khasakhala, Anne

    2009-07-01

    Using retrospective data from the Urban Integration Survey conducted in 2001 in Nairobi, Kenya, on a sample of 955 women and men aged 25-54, this paper compares factors influencing entry into union formation for men and women. The analysis uses event history methods, specifically Cox Proportional Hazards regression, stratified by age cohort and run separately by sex. The results indicate that delay in union formation is more pronounced for women than for men. Cohabitation without formal marriage is the prominent form of union, especially among the younger generation, and appears to have increased. For men, the timing of union is more dependent upon human capital acquisition than on cultural factors. These findings show that the marriage search model, which was first applied in Western countries, can also hold in cities of developing countries. Nonetheless, neither the search model nor the integration or the independence models apply to women's union formation, which very few exogenous factors can explain. PMID:19250585

  13. Factors influencing internal color of cooked meats.

    PubMed

    Suman, Surendranath P; Nair, Mahesh N; Joseph, Poulson; Hunt, Melvin C

    2016-10-01

    This manuscript overviews the pertinent research on internal color of uncured cooked meats, biochemical processes involved in meat cookery, and fundamental mechanisms governing myoglobin thermal stability. Heat-induced denaturation of myoglobin, responsible for the characteristic dull-brown color of cooked meats, is influenced by a multitude of endogenous (i.e., pH, muscle source, species, redox state) and exogenous (i.e., packaging, ingredients, storage) factors. The interactions between these factors critically influence the internal cooked color and can confuse the consumers, who often perceive cooked color to be a reliable indicator for doneness and safety. While certain phenomena in cooked meat color are cosmetic in nature, others can mislead consumers and result in foodborne illnesses. Research in meat color suggests that processing technologies and cooking practices in industry as well as households influence the internal cooked color. Additionally, the guidelines of many international public health and regulatory authorities recommend using meat thermometers to determine safe cooking endpoint temperature and to ensure product safety. PMID:27131513

  14. INFLUENCE OF OSMOTIC PRESSURE ON THE MORPHOLOGY OF THE REITER TREPONEME

    PubMed Central

    Hardy, Paul H.; Nell, E. Ellen

    1961-01-01

    Hardy, Paul H., Jr. (Johns Hopkins University, Baltimore, Md.) and E. Ellen Nell. Influence of osmotic pressure on the morphology of the Reiter treponeme. J. Bacteriol. 82: 967–978. 1961.—Spherical bodies similar to those that develop spontaneously in cultures of treponemes, and which have been considered by many investigators to represent one stage in a complex life cycle of these organisms, can be produced rapidly with the Reiter treponeme by merely altering the medium in which the organisms are suspended. Osmotic pressure appears to be the major factor responsible for this effect, as shown by the observation that treponemes suspended in NaCl solutions of 0.15 to 0.10 m retain their spirochetal morphology, whereas organisms suspended in more dilute salt solutions rapidly become spherical. Moreover, the concentration of salt appears to influence both the rate and extent of sphere formation. Further evidence that osmotic pressure is primarily involved is demonstrated by the selectivity of the conditions under which spheres form. Treponemes suspended in various 0.3 osmolal solutions either retain their spiral shape or form spheres, depending upon the nature of the solute. Viability studies of suspensions containing predominantly spherical forms, which have developed spontaneously or have been artificially induced, have failed to produce evidence that the resulting growth of treponemes came from the spheres. It is concluded, therefore, that the naturally occurring spheres probably arise as the result of an osmotic imbalance which develops between the cells and their environment, and that the spheres represent degenerative forms rather than an intermediate stage in a life cycle. Images PMID:13904666

  15. 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.

  16. 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.

  17. Factors influencing variation in dentist service rates.

    PubMed

    Grembowski, D; Milgrom, P; Fiset, L

    1990-01-01

    In the previous article, we calculated dentist service rates for 200 general dentists based on a homogeneous, well-educated, upper-middle-class population of patients. Wide variations in the rates were detected. In this analysis, factors influencing variation in the rates were identified. Variation in rates for categories of dental services was explained by practice characteristics, patient exposure to fluoridated water supplies, and non-price competition in the dental market. Rates were greatest in large, busy practices in markets with high fees. Older practices consistently had lower rates across services. As a whole, these variables explained between 5 and 30 percent of the variation in the rates. PMID:2118182

  18. Biomechanics of Traumatic Brain Injury: Influences of the Morphologic Heterogeneities of the Cerebral Cortex

    PubMed Central

    Gervaise, H.M.T.; van Dommelen, J.A.W.; Geers, M.G.D.

    2008-01-01

    Traumatic brain injury (TBI) can be caused by accidents and often leads to permanent health issues or even death. Brain injury criteria are used for assessing the probability of TBI, if a certain mechanical load is applied. The currently used injury criteria in the automotive industry are based on global head kinematics. New methods, based on finite element modeling, use brain injury criteria at lower scale levels, e.g., tissue-based injury criteria. However, most current computational head models lack the anatomical details of the cerebrum. To investigate the influence of the morphologic heterogeneities of the cerebral cortex, a numerical model of a representative part of the cerebral cortex with a detailed geometry has been developed. Several different geometries containing gyri and sulci have been developed for this model. Also, a homogeneous geometry has been made to analyze the relative importance of the heterogeneities. The loading conditions are based on a computational head model simulation. The results of this model indicate that the heterogeneities have an influence on the equivalent stress. The maximum equivalent stress in the heterogeneous models is increased by a factor of about 1.3–1.9 with respect to the homogeneous model, whereas the mean equivalent stress is increased by at most 10%. This implies that tissue-based injury criteria may not be accurately applied to most computational head models used nowadays, which do not account for sulci and gyri. PMID:18465248

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

    PubMed Central

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

    2015-01-01

    Summary 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. PMID:25959734

  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. PMID:16521499

  1. 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

  2. Factors influencing breast changes after pregnancy.

    PubMed

    Rauh, Claudia; Faschingbauer, Florian; Haeberle, Lothar; Jud, Sebastian M; Heusinger, Katharina; Fasching, Peter A; Goecke, Tamme W; Rajakaruna, Nadeeka; Voigt, Franziska; Bani, Mayada R; Lux, Michael P; Renner, Stefan P; Loehberg, Christian R; Hartmann, Arndt; Schulz-Wendtland, Ruediger; Beckmann, Matthias W; Bayer, Christian M

    2013-05-01

    Pregnancy and breastfeeding are major factors reducing breast cancer (BC) risk. A potential mechanism for this effect might be changes in mammographic density, but other factors might be involved. The aim of this study was to investigate factors influencing changes in breast size and breast stiffness after pregnancy. Of a consecutive cohort of 5991 women who gave birth between 1996 and 1999, 559 replied to a questionnaire including questions about breast changes. The women completed their own assessments of changes in breast size and stiffness since their last pregnancy. Factors being investigated regarding their predictive value for these changes were: BMI before pregnancy, weight gain, age at first full-term pregnancy (FFTP), number of pregnancies, breastfeeding, and BMI of the children's fathers. A decrease in breast size was reported in 21.8% of the participants and an increase in 35.1%. With regard to the breast stiffness, 66.4% reported a decrease and only 5% reported an increase. Independent predictors for increased breast size were age at FFTP, increase in BMI since last pregnancy, BMI before pregnancy, and time since FFTP. Factors predictive of greater breast stiffness included age at FFTP, BMI before FFTP, time since FFTP, breastfeeding status, and number of pregnancies. Breast changes after pregnancy depend on several variables, which are described as BC-risk factors. Individual reaction of the female breast to a pregnancy leads to different outcomes with regard to breast size and stiffness. Further studies are needed to clarify whether these individual responses interact with the effect of pregnancy on the BC risk. PMID:23022745

  3. Factors that influence engagement in collaborative practice

    PubMed Central

    Herbert, Carol P.; Bainbridge, Lesley; Bickford, Julia; Baptiste, Susan; Brajtman, Susan; Dryden, Trish; Hall, Pippa; Risdon, Cathy; Solomon, Patricia

    2007-01-01

    OBJECTIVE To generate hypotheses regarding factors that might influence engagement in collaborative practice. DESIGN Qualitative study using in-depth interviews. SETTING Participants interviewed each other in dyads. The pairing was based upon geographical location and proximity to each other. PARTICIPANTS Eight professionals from the disciplines of medicine, nursing, occupational therapy, physical therapy, and massage therapy. METHOD Semistructured interviews, lasting 30 to 45 minutes each, were recorded and transcribed verbatim. The transcripts were read by all research team members using independent content analysis for common words, phrases, statements, or units of text for key themes. At a subsequent face-to-face meeting, the team used an iterative process of comparing and contrasting key themes until consensus was reached. The transcripts were then analyzed further for subthemes using NVivo software. MAIN FINDINGS Initial findings suggest that some common characteristics grounded in family history, school experiences, social interactions, and professional training might influence collaborative practice choices. The narrative form of the interview broke down interpersonal and interprofessional barriers, creating a new level of trust and respect that could improve professional collaboration. CONCLUSION This study suggests that life experiences from childhood into later adulthood can and do influence professional choices. PMID:17872847

  4. Morphological patterns of southeastern Mediterranean river mouths: The topographic setting of the beach as a forcing factor

    NASA Astrophysics Data System (ADS)

    Lichter, Michal; Zviely, Dov; Klein, Micha

    2010-11-01

    Israeli Mediterranean river mouths are characterized by an extremely dynamic morphology, as their channels tend to migrate hundreds of meters north and south along the shoreline. This study aims to characterize the impact of the topographic setting of the beach on the dynamic morphology of seven of these river mouths. This was achieved by morphologically mapping and monitoring the natural channel dynamics of each mouth over time; recognizing their spatial and temporal migration and avulsion patterns; describing, generalizing and classifying the different types of river mouths present on the coast; and investigating the influence of the adjacent topography on their morphology. Detailed geomorphologic mapping was achieved using remote sensing and GIS techniques, utilizing more than 300 aerial photographs taken between 1918 and 2005. This study revealed a number of typical differences in these patterns, attributed to differences in the topographic setting of the beach in the vicinity of the mouths. "Elongated strip" topography coasts demonstrate a uniform slope beach with equally spaced elevation contours, forming a narrow sandy strip between the shoreline and the back-berm. "Funnel" topography coasts exhibit a non-uniform slope with a funnel-shaped topographic depression adjacent to the river mouth. Similarities were found between the spatial and the temporal morphological patterns of river mouths flowing in each of these two topographical settings. Elongated strip mouths are deflected alongshore a barrier and demonstrate high migration distances and little temporal change. The morphology of funnel mouths was found to be highly temporally variable yet less spatially dynamic, as these mouths' channels are restricted by their funnel topography. This study concludes that the topographic setting of the beach, a constant element in the temporal scale of this study, is a primary factor influencing the morphology of the studied mouths.

  5. Factors affecting the acquisition of plural morphology in Jordanian Arabic.

    PubMed

    Albirini, Abdulkafi

    2015-07-01

    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 notion of default over several years. Sixty Jordanian children, equally divided among six age groups (three to eight years), completed an oral real-word pluralization task and a nonsense-word pluralization task. The findings indicate that feminine sound plurals are acquired before and extended to the other plural forms. Productivity and frequency seem to shape the acquisition patterns among younger children, but predictability becomes more critical at a later age. Younger children use the most productive plural as the default form, but older children tend to use two default forms based on frequency distributions in the adult language. The theoretical implications of the findings are discussed. PMID:25158792

  6. 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

  7. Factors influencing BMI classifications of Korean adults

    PubMed Central

    Chang, Ae Kyung; Choi, Jin Yi

    2015-01-01

    [Purpose] This study aimed to identify factors influencing the BMI classifications of 3,583 Korean adults using data from the fifth Korean National Health and Nutrition Examination Survey. [Subjects and Methods] Measures included lifestyle factors, physiologic factors, perceived health state, stress, subjective body recognition, health-related quality of life, and weight control behavior. [Results] Body perception scores were lower with underweight and higher with overweight and obesity than with a healthy weight. There was a lower proportion of underweight men and a higher proportion of overweight or obese men than women. Instances of Alcohol Use Identification Scores (AUDIT) ≥ 9 were proportionately lower with underweight and more with overweight or obesity relative to an AUDIT score < 9 with healthy weight. Hemoglobin A1c and systolic blood pressure were higher with obesity than with healthy weight. The total cholesterol level was greater with overweight and obesity than with healthy weight. [Conclusion] These results suggest that obesity intervention for adults should be based on age and sex and should include drinking habits and physical activity. PMID:26157264

  8. Factors Controlling Tidal Flat Morphology in South San Francisco Bay

    NASA Astrophysics Data System (ADS)

    Bearman, J. A.; Foxgrover, A.; Friedrichs, C.; Jaffe, B.

    2006-12-01

    Since the 1850's, the San Francisco Bay has been subjected to a wide array of human-induced change. From the time of the first US Coast and Geodetic Survey bathymetric surveys in 1858, the saltmarshes and mudflats of South San Francisco Bay (SSFB) have decreased in area by 80% and 40%, respectively. Much of the saltmarsh loss was due to salt pond leveeing, while mudflat loss can be related to lack of sediment input, wind-wave erosion, and sea level rise. Plans for marsh restoration include breaching of salt pond levees with the goal of restoring the 15,100 acres of acquired ponds to tidal marsh the largest such restoration in the western US. The effect this would have upon the adjacent mudflats is unclear. In this analysis, the tidal flats of SSFB are broken into geographically similar regions and multiple cross-sections are drawn from mean high water to below mean lower low water at close intervals, allowing for a mean tidal flat bathymetric profile to be determined for each segment and for each time period 1858, 1898, 1931, 1956, 1983, 2005. Eigenfunction analysis is used to separate the spatial and temporal changes in profile shape into the dominant components of variability, allowing evaluation of the behavior of mudflats relative to spatially and temporally-varying forcings. The components of bathymetric variability derived from objective statistical analysis are compared to theoretical models for tidal flat profiles as a function of waves, tides and sediment supply. Theoretical models predict that wave-dominated or sediment-starved flats tend to have concave-upwards bathymetric profiles, whereas tide-dominated or accretionary flats tend to have convex-upwards bathymetric profiles. Initial results from an analysis of the 1980's bathymetry data suggest the South Bay mudflats can be broken into three morphologically distinct sections: 1) concave-up, erosional mudflats in the Eastern zone, which is most subject to wind waves; 2) convex-up, accretionary flats in

  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. Factors influencing the uptake of orthodontic treatment.

    PubMed

    O'Brien, K; McComb, J L; Fox, N; Wright, J

    1996-11-01

    The aim of this investigation was to evaluate the factors that influenced the uptake of orthodontic treatment for patients who were referred for orthodontic treatment to two types of orthodontic treatment provider; a fee per item and hospital service. The following data were collected: (i) basic demographic data; (ii) the need for orthodontic treatment as measured by IOTN; and (iii) the outcome of the consultation. The data analysis with logistic regression revealed that the following variables had a predictive effect on the uptake of treatment: (i) the need for orthodontic treatment; and (ii) the patient's gender. Most of the patients that were referred and accepted for treatment had a definite need for orthodontic treatment. PMID:8985570

  11. Factors influencing human leukocyte adherence in vitro.

    PubMed

    Stepniewicz, W; Tchórzewski, H; Luciak, M

    1983-01-01

    Studies were performed on factors influencing leucocyte adherence in vitro. Blood condensation was found to increase leukocyte adherence. Addition of heparin, dextran or ethanol caused a significant reduction of white blood cell count in blood samples in comparison with blood mixed with sodium EDTA or ACD solution. This suggests the existence of two granulocyte subpopulations; viz, rapidly adhering and slowly adhering. Heparin enhanced granulocyte adherence, while dextran and ethanol decreased it. Five-day storage of ACD blood led to a decrease in granulocyte adherence, while addition of heparin or histamine to ACD blood prevented this change to occur. The glucose concentration of 1,000 mg/dl augmented granulocyte adherence, while higher glucose concentrations induced its progressive fall below the control values. There was no significant change of lymphocyte adherence during the experiments. PMID:6194070

  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. Influence of bank vegetation on channel morphology in rural and urban watersheds

    NASA Astrophysics Data System (ADS)

    Hession, W. C.; Pizzuto, J. E.; Johnson, T. E.; Horwitz, R. J.

    2003-02-01

    Stream-bank vegetation significantly influences the morphology of streams in the Piedmont region of the United States. We surveyed the morphology of 26 paired stream reaches in southeastern Pennsylvania, northern Maryland, and Delaware. One member of each pair has a forested riparian zone, whereas the other has a riparian zone composed pri marily of grass. The paired reaches are nearly contiguous, so all significant channel-forming variables except riparian vegetation are held constant. The extent of urban development of the watersheds upstream of the paired reaches also varies considerably, allowing us to determine the combined influence of riparian vegetation and urbanization on channel morphology. Statistical analyses indicate that (1) channels with forested riparian zones are wider than channels with nonforested riparian zones, (2) channels in urbanized watersheds are wider than channels in nonurbanized watersheds, and (3) the effect of riparian vegetation is independent of the level of urbanization.

  14. Factors influencing consumer dietary health preventative behaviours

    PubMed Central

    Petrovici, Dan A; Ritson, Christopher

    2006-01-01

    Background The deterioration of the health status of the Romanian population during the economic transition from a centrally planned to a free market economy has been linked to lifestyles factors (e.g. diet) regarded as a main determinants of the disparity in life expectancy between Eastern and Western Europe. Reforms in the health care system in this transition economy aim to focus on preventive action. The purpose of this study was to identify the factors that impact on the individual decision to engage in Dietary Health Preventive Behaviour (DHPB) and investigate their influence in the context of an adapted health cognition model. Methods A population-based study recruited 485 adult respondents using random route sampling and face-to-face administered questionnaires. Results and discussion Respondents' health motivation, beliefs that diet can prevent disease, knowledge about nutrition, level of education attainment and age have a positive influence on DHPB. Perceived barriers to healthy eating have a negative impact on alcohol moderation. The information acquisition behaviour (frequency of reading food labels) is negatively predicted by age and positively predicted by health motivation, education, self-reported knowledge about nutrition and household financial status. A significant segment of respondents believe they are not susceptible to the elicited diseases. Health promotion strategies should aim to change the judgments of health risk. Conclusion The adaptation of the Health Belief Model and the Theory of Health Preventive Behaviour represents a valid framework of predicting DHPB. The negative sign of perceived threat of disease on DHPB may suggest that, under an income constraint, consumers tend to trade off long-term health benefits for short-term benefits. This cautions against the use of negative messages in public health campaigns. Raising the awareness of diet-disease relationships, knowledge about nutrition (particularly sources and risks associated

  15. Influence of chronic arsenic poisoning on bone marrow morphology. A case report.

    PubMed

    Pralle, H; Manz, F

    1985-01-01

    Arsenic is widely used for the production of insecticides, paints, ceramics and for the preparation of textiles, leather and furs. Nevertheless hematologists are almost unaware of the influence of arsenic on bone marrow morphology. In the case described here we have found slight megaloblastic hemopoiesis, typical karyorrhexis in erythropoietic accompanied by basophilic stippling and impairment of mitoses in megakaryocytes and granulopoietic cells. PMID:3967100

  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. The Krüppel-Like Factor Dar1 Determines Multipolar Neuron Morphology

    PubMed Central

    Wang, Xin; Zhang, Macy W.; Kim, Jung Hwan; Macara, Ann Marie; Sterne, Gabriella; Yang, Tao

    2015-01-01

    Neurons typically assume multipolar, bipolar, or unipolar morphologies. Little is known about the mechanisms underlying the development of these basic morphological types. Here, we show that the Krüppel-like transcription factor Dar1 determines the multipolar morphology of postmitotic neurons in Drosophila. Dar1 is specifically expressed in multipolar neurons and loss of dar1 gradually converts multipolar neurons into the bipolar or unipolar morphology without changing neuronal identity. Conversely, misexpression of Dar1 or its mammalian homolog in unipolar and bipolar neurons causes them to assume multipolar morphologies. Dar1 regulates the expression of several dynein genes and nuclear distribution protein C (nudC), which is an essential component of a specialized dynein complex that positions the nucleus in a cell. We further show that these genes are required for Dar1-induced multipolar neuron morphology. Dar1 likely functions as a terminal selector gene for the basic layout of neuron morphology by regulating both dendrite extension and the dendrite–nucleus coupling. SIGNIFICANCE STATEMENT The three basic morphological types of neurons—unipolar, bipolar, and multipolar—are important for information processing and wiring of neural circuits. Little progress has been made toward understanding the molecular and cellular programs that generate these types since their discovery over a century ago. It is generally assumed that basic morphological types of neurons are determined by the number of dendrites growing out from the cell body. Here, we show that this model alone is insufficient. We introduce the positioning of nucleus as a critical factor in this process and report that the transcription factor Dar1 determines multipolar neuron morphology in postmitotic neurons by regulating genes involved in nuclear positioning. PMID:26490864

  19. Factors Influencing Early Dental Implant Failures.

    PubMed

    Chrcanovic, B R; Kisch, J; Albrektsson, T; Wennerberg, A

    2016-08-01

    The purpose of the present study was to assess the influence of local and systemic factors on the occurrence of dental implant failures up to the second-stage surgery (abutment connection). This retrospective study is based on 2,670 patients who received 10,096 implants and were consecutively treated with implant-supported prostheses between 1980 and 2014 at 1 specialist clinic. Several anatomic-, patient-, health-, and implant-related factors were collected. Descriptive statistics were used to describe the patients and implants. Univariate and multivariate logistic regression models were used at the patient level as well as the implant level to evaluate the effect of explanatory variables on the failure of implants up to abutment connection. A generalized estimating equation method was used for the implant-level analysis to account for the fact that repeated observations (several implants) were available for a single patient. Overall, 642 implants (6.36%) failed, of which 176 (1.74%) in 139 patients were lost up to second-stage surgery. The distribution of implants in sites of different bone quantities and qualities was quite similar between implants lost up to and after abutment connection. Smoking and the intake of antidepressants were the statistically significant predictors in the multivariate model (ClinicalTrials.gov NCT02369562). PMID:27146701

  20. Influencing Factors of Thermogenic Adipose Tissue Activity.

    PubMed

    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

  1. 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

  2. Influence of magnetic field on the morphology of the andrographolide crystal from supercritical carbon dioxide extraction crystallization

    NASA Astrophysics Data System (ADS)

    Chen, Kexun; Zhang, Xingyuan; Pan, Jian; Zhang, Wencheng; Yong, Ji; Yin, Wenhong

    2003-10-01

    In this paper, a supercritical fluid extraction-crystallization of andrographolide, a kind of Chinese traditional medicine, was investigated. We have studied the extraction-crystallization process with or without magnet in the extractor, respectively. It was found that the presence of magnetic field is an important factor influencing the quality of the products. SEM images showed that the crystal was slice-like in shape, and many slices reunited together in the absence of magnet. Further research showed that pressure had a certain effect on the morphology of the crystal.

  3. "Push-Pull" Factors Influencing International Student Destination Choice.

    ERIC Educational Resources Information Center

    Mazzarol, Tim; Soutar, Geoffrey N.

    2002-01-01

    Examined factors motivating international student choice of host country. Found that economic and social factors within the home country serve to "push" students abroad, while a variety of "pull" factors influence selection of a host country. (EV)

  4. 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

    2016-05-01

    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

  5. 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

  6. Factors influencing birth control habits in Victoria.

    PubMed

    Selwood, T; Leeton, J

    1981-02-01

    A survey was conducted in March 1978 for the purpose of comparing the contraceptive habits of Melbourne and ex-Melbourne populations in Victoria. Of the 1312 records of sexually active persons collected in 1978, 1254 of those persons were between the ages of 15 and 49. Recorded information included age, sex, marital status, and place of domicile (Melbourne or ex-Melbourne, Victoria). When the Melbourne population was compared with the rest of Victoria, the proportion using each method of contraception was much the same for each group. A marked difference was the proportion using withdrawal in Melbourne; this was over 3 times the proportion among the ex-Melbourne population. Over 35% of persons under age 30 used oral contraceptives (OCs), compared with 24.2 in the over 30 age range. Barrier methods and natural family planning methods and withdrawal were commonly used by the older age groups. A large proportion of the over age 30 group used sterilization and hysterectomy as forms of birth control. Individuals in "de facto" relationships showed a tendency towards more reliable forms of contraception than did other groups. Only 20.3% were not using some form of contraception. Single persons were frequent OC users and users of barrier methods. 28.1% used no form of contraception. The sex of the person interviewed in the survey revealed a bias. Males tended to report male birth control methods and female reported female methods rather than those used by partners of the opposite sex. Marital status influenced birth control choice. The choice of birth control for each marital status was influenced by the confounding factor of mean age of each group. PMID:7247847

  7. Platelets to rings: Influence of sodium dodecyl sulfate on Zn-Al layered double hydroxide morphology

    SciTech Connect

    Yilmaz, Ceren; Unal, Ugur; Yagci Acar, Havva

    2012-03-15

    In the current study, influence of sodium dodecyl sulfate (SDS) on the crystallization of Zn-Al layered double hydroxide (LDH) was investigated. Depending on the SDS concentration coral-like and for the first time ring-like morphologies were obtained in a urea-hydrolysis method. It was revealed that the surfactant level in the starting solution plays an important role in the morphology. Concentration of surfactant equal to or above the anion exchange capacity of the LDH is influential in creating different morphologies. Another important parameter was the critical micelle concentration (CMC) of the surfactant. Surfactant concentrations well above CMC value resulted in ring-like structures. The crystallization mechanism was discussed. - Graphical abstract: Dependence of ZnAl LDH Morphology on SDS concentration. Highlights: Black-Right-Pointing-Pointer In-situ intercalation of SDS in ZnAl LDH was achieved via urea hydrolysis method. Black-Right-Pointing-Pointer Morphology of ZnAl LDH intercalated with SDS depended on the SDS concentration. Black-Right-Pointing-Pointer Ring like morphology for SDS intercalated ZnAl LDH was obtained for the first time. Black-Right-Pointing-Pointer Growth mechanism was discussed. Black-Right-Pointing-Pointer Template assisted growth of ZnAl LDH was proposed.

  8. Evaluation of clinical, laboratory and morphologic prognostic factors in colon cancer

    PubMed Central

    Grande, Michele; Milito, Giovanni; Attinà, Grazia Maria; Cadeddu, Federica; Muzi, Marco Gallinella; Nigro, Casimiro; Rulli, Francesco; Farinon, Attilio Maria

    2008-01-01

    Background The long-term prognosis of patients with colon cancer is dependent on many factors. To investigate the influence of a series of clinical, laboratory and morphological variables on prognosis of colon carcinoma we conducted a retrospective analysis of our data. Methods Ninety-two patients with colon cancer, who underwent surgical resection between January 1999 and December 2001, were analyzed. On survival analysis, demographics, clinical, laboratory and pathomorphological parameters were tested for their potential prognostic value. Furthermore, univariate and multivariate analysis of the above mentioned data were performed considering the depth of tumour invasion into the bowel wall as independent variable. Results On survival analysis we found that depth of tumour invasion (P < 0.001; F-ratio 2.11), type of operation (P < 0.001; F-ratio 3.51) and CT scanning (P < 0.001; F-ratio 5.21) were predictors of survival. Considering the degree of mural invasion as independent variable, on univariate analysis, we observed that mucorrhea, anismus, hematocrit, WBC count, fibrinogen value and CT scanning were significantly related to the degree of mural invasion of the cancer. On the multivariate analysis, fibrinogen value was the most statistically significant variable (P < 0.001) with the highest F-ratio (F-ratio 5.86). Finally, in the present study, the tumour site was significantly related neither to the survival nor to the mural invasion of the tumour. Conclusion The various clinical, laboratory and patho-morphological parameters showed different prognostic value for colon carcinoma. In the future, preoperative prognostic markers will probably gain relevance in order to make a proper choice between surgery, chemotherapy and radiotherapy. Nevertheless, current data do not provide sufficient evidence for preoperative stratification of high and low risk patients. Further assessments in prospective large studies are warranted. PMID:18778464

  9. 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.

  10. 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…

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

    USGS Publications Warehouse

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

    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.

  12. Competing influences on morphological modularity in biomechanical systems: a case study in mantis shrimp.

    PubMed

    Anderson, Philip S L; Smith, Danielle C; Patek, S N

    2016-05-01

    Related species that share similar biomechanical systems and segmentation patterns may exhibit different patterns of morphological covariation. We examined morphological covariation of the potent prey capture appendage of two mantis shrimp (Stomatopoda) species-a spearer (Squilla empusa) and smasher (Gonodactylaceus falcatus). We assessed three frameworks for modularity, two based on the biomechanics of the appendage and one based on its segmentation as a proxy for shared developmental pathways. We collected morphometric data from S. empusa, and compared morphological covariation patterns across the raptorial appendage with patterns from a new analysis of previously published morphometric data from G. falcatus. The relative importance of the different hypothetical influences differed between the two species, and was dependent on whether specimens were analyzed all together or subdivided based on sex or sub-populations, including one particularly distinct population in the Gulf of Mexico. We also found an intriguing handedness pattern in which right-hand appendages had a variable number of spines, whereas the left had a constant number of spines. Overall, our findings highlight the importance of testing multiple, alternative frameworks for morphological covariation and suggest that mantis shrimp experience contrasting influences on covariation depending on their feeding mechanisms. PMID:27161948

  13. Factors influencing informal care-giving.

    PubMed

    Holmes, Ann M.; Deb, Partha

    1998-07-01

    BACKGROUND: As downsizing of institutional care continues, patients discharged are likely to have more severe mental illnesses, and to have experienced longer tenures within institutions than patients who have been discharged in the past. As greater numbers of patients are removed from mental hospitals, the objective burden experienced by informal care-givers may increase, particularly if formal care levels are inadequate. AIMS OF THE STUDY: This paper documents who assumes informal care-giver roles, and the form such care-giving takes for patients discharged from a state hospital. Specifically, this paper identifies (i) what factors affect a person's decision to assume a care-giver role, including the participation of other network members in care-giving, (ii) what factors influence whether care-giving is provided in time or in direct purchase of care and (iii) how the patient's treatment location affects the decision of the network member to assume any care-giving role. DATA AND ANALYTICAL METHODS: Data for this paper are taken from a longitudinal study of the closure of a state mental hospital in central Indiana. Seventy-seven patients were asked to identify their community networks. Ninety-eight network members were surveyed about the informal care, both in time or through direct expenditures, they provided to these patients one year after discharge. Care-giving relationships were estimated using a multivariate probit model. Such a model estimates the extent to which the decision to provide care in either form depends on the care-giving activities assumed by other network members associated with a given patient, as well as the characteristics of individual patients and network members. RESULTS: Forty-one per cent of network members provided some level of informal care, with 13.3% providing some care in time, and 35.7% providing some care through direct expenditures. A positive relationship was found between participation in informal care-giving and the

  14. Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung

    SciTech Connect

    Rombout, P.J.A.; Dormans, J.A.M.A.; Marra, M.; van Esch, G.J.

    1986-12-01

    Experiments were performed to study the influence of concentration, exposure pattern, and length of exposure on the degree and extent of morphological alterations in the NO/sub 2//sup -/ exposed rat lung. Four weeks of continuous exposure to 20 mg NO/sub 2//m/sup 3/ consecutively revealed damage and loss of cilia, replacement of desquamated type I pneumocytes by type II pneumocytes resulting in a cuboidal epithelial lining, an influx of alveolar macrophages, and hypertrophy and hyperplasia of the bronchiolar epithelium. The animals recovered almost completely from the induced lesions within 8 days. Continuous exposure to 1, 2.5, or 5 mg/m/sup 3/ displayed minimal alterations in the 5 mg/m/sup 3/ group. The effects increased with exposure time. Intermittent or continuous exposure to 20 mg NO/sub 2//m/sup 3/ resulted in minor differences after 4 weeks. The onset of the lesions was delayed and the massive influx of alveolar macrophages in the continuously exposed animals failed to appear in the intermittently exposed animals. This work demonstrates that in subacute experiments: (1) Concentration plays a more important role in inducing pulmonary lesions than exposure time when the product of concentration and time is kept constant. This effect is stronger during intermittent exposure than during continuous exposure. (2) Continuous exposure seems to be a more important factor with regard to a macrophage response than intermittent exposure. (3) The rat lung has a large capacity to repair almost completely from damage caused by short-term NO/sub 2/ exposure.

  15. Nanoscale morphology dependent pseudocapacitance of NiO: Influence of intercalating anions during synthesis

    NASA Astrophysics Data System (ADS)

    Meher, Sumanta Kumar; Justin, P.; Ranga Rao, G.

    2011-02-01

    Three nano-porous NiO samples with high specific surface area were prepared by a simple hydrothermal method under homogeneous precipitation conditions using CTAB as a template and urea as the hydrolysis controlling agent. This study was done to determine the effect of different anions (acetate, nitrate and chloride) present in the precursor salts on the morphology and pseudocapacitance behavior of NiO. The samples were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Brunauer-Emmet-Teller (BET) isotherm and field emission scanning electron microscopy (FESEM). The final NiO samples showed different hierarchical surface morphologies and their effect on the electrochemical pseudocapacitance behavior was carefully studied by cyclic voltammetry, galvanostatic charge-discharge cycles (chronopotentiometry) and impedance spectroscopic techniques. The specific capacitance of NiO sample synthesized by NO3- ion intercalation showed higher surface area, intermediate porosity and a novel pine-cone morphology with nano-wire surface attachments. This sample exhibits the highest pseudocapacitance of 279 F g-1 at a scan rate of 5 mV s-1, calculated from the cyclic voltammetry measurements. The sample synthesized by Cl- intercalation shows a nano-flower morphology with lower surface area, porosity and pseudocapacitance behaviour. The NiO sample prepared in the presence of CH3COO- ions showed a honeycomb type surface morphology with an intermediate pseudocapacitance value but higher reversibility. The galvanostatic charge-discharge and impedance spectroscopic measurements on these NiO electrodes were consistent with CV results. The Coulombic efficiency of all the three NiO samples was found to be high (~85 to ~99%) after 100 galvanostatic charge-discharge cycles. This study shows that the surface morphology and porosity of NiO are strongly influenced by the anions in the precursor salts, and in turn affect significantly

  16. Factors influencing wetland use by Canada geese

    USGS Publications Warehouse

    Naugle, D.E.; Gleason, J.S.; Jenks, J.A.; Higgins, K.F.; Mammenga, P.W.; Nusser, S.M.

    1997-01-01

    Seasonal and semi-permanent wetlands in eastern South Dakota were surveyed in 1995 and 1996 to identify habitat characteristics influencing wetland use by Canada geese (Branta canadensis maxima). Position of a wetland within the landscape and its area were important landscape-scale features influencing wetland use by geese. Our delineation of potential Canada goose habitat using a wetland geographic information system indicated that distribution and area of semi-permanent wetlands likely limit Canada goose occurrence in regions outside the Prairie Coteau. Periodicity in hydrologic cycles within landscapes also may influence goose use of wetlands in eastern South Dakota.

  17. 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. PMID:21690240

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

    PubMed

    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

  19. 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

  20. 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…

  1. 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.

  2. 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.

  3. Factors Influencing Simultaneous Communication Behaviors in Teachers.

    ERIC Educational Resources Information Center

    Stewart, David A.; And Others

    1988-01-01

    Simultaneous communication used by four teachers in formal lessons was investigated, to determine the extent to which signs and speech matched and to delineate factors predicting communication behavior. Simultaneous communication was found to be sign-driven or speech-driven depending on factors such as student comprehension, teacher's expertise,…

  4. Is Subjective Status Influenced by Psychosocial Factors?

    ERIC Educational Resources Information Center

    Lundberg, Johanna; Kristenson, Margareta

    2008-01-01

    Objective: Associations between subjective status and health are still relatively unexplored. This study aimed at testing whether subjective status is uniquely confounded by psychosocial factors compared to objective status, and what factors that may predict subjective status. Design: A cross-sectional analysis of a population-based, random sample…

  5. 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…

  6. The influence of catalyst layer morphology on the electrochemical performance of DMFC anode

    NASA Astrophysics Data System (ADS)

    Wang, Zhanliang; Liu, Yang; Linkov, Vladimir M.

    The anodes with different morphology for DMFC were prepared, and the influences of the microstructure of anode catalyst layer on their electrochemical performance were investigated by scanning electrochemical microscopy (SECM), scanning electron microscopy (SEM), proton induced X-ray emission (PIXE) and electrochemical methods, respectively. The surface morphology of catalyst layer was observed by SEM, and the elements dispersion status and its distribution of activity intensity on electrode catalyst layer were mapped by PIXE and SECM, respectively. Electrochemical impedance spectroscopy (EIS) and anode polarization experiment were employed to analyze the electrochemical properties of anode. The results reveal that the anode with a relative smooth surface of catalyst layer and less cracks shows good interfacial properties and the lower resistance on the electrode reaction of methanol, and its maximum power of MEA as a single cell was about 178 mW cm -2 at 70 °C.

  7. 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.

  8. Factors Influencing L2 Gender Processing

    ERIC Educational Resources Information Center

    Bordag, Denisa; Pechmann, Thomas

    2007-01-01

    In four experiments we explored processes underlying L2 gender retrieval. We focused on L1 interference and on the influence of the L2 noun's termination. In Experiments 1 and 2 we tried to manipulate the intensity of L1 interference. We found that L2 speakers cannot eliminate or substantially reduce the interlingual interference neither when they…

  9. 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…

  10. FACTORS AND PRACTICES THAT INFLUENCE LIVESTOCK DISTRIBUTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inconsistent livestock distribution in extensive rangeland pastures continues as a vexing problem for land and livestock managers. Dispersal patterns of cattle are affected by abiotic factors like degree of slope, distance from water, shade, physical barriers, temperature extremes and precipitation...

  11. Microtubule inhibitors block the morphological changes induced in Drosophila blood cells by a parasitoid wasp factor.

    PubMed

    Rizki, R M; Rizki, T M

    1990-03-15

    The shape change of Drosophila melanogaster blood cells (lamellocytes) from discoidal to bipolar that is caused by a factor from the female parasitoid Leptopilina heterotoma is blocked by the tubulin inhibitors vinblastine and vincristine in vitro. The actin inhibitor, cytochalasin B, causes arborization of Drosophila lamellocytes and acts synergistically with the wasp factor to alter lamellocyte morphology. Lamellocyte aborization induced by cytochalasin B is blocked by simultaneous treatment with vinblastine. These observations indicate that the changes in lamellocyte shape induced by both the wasp factor and cytochalasin B require microtubule assembly. PMID:2311722

  12. Influence of the morphology of lycopodium dust on its minimum ignition energy

    SciTech Connect

    Thomas, G.O.; Oakley, G.; Brenton, J. )

    1991-06-01

    Lycopodium, which exhibits a particularly uniform particle size, has been relatively widely used as a reference when studying dust cloud ignition. Lycopodium was used to determine the influence of discharge circuit parameters on minimum ignition energy. It is therefore a natural choice as a calibration dust when developing a new facility for the determination of ignition energies. During the initial evaluation period in this latter study significant differences were observed in the minimum energies of different samples of lycopodium. These differences have now been traced to differing morphologies between the samples.

  13. [The influences of anterior disc displacement on oral mandibular function and morphology and their biological mechanisms].

    PubMed

    Xia, Wendi; Fu, Kiayuan

    2016-03-01

    Anterior disc displacement is a common subtype seen in temporomandibular disorders (TMD) patients. It may cause mandibular movement disorders, such as clicking of joint, intermittent closed lock, limitation of mouth opening, etc. These disorders may affect the life qualities of patients. Anterior disc displacement may also cause mandibular malformations, especially among adolescents, which may affect the growth of condyle, therefore may have a correlation with mandibular retrusion or mandibular deviation when grown up. This paper going to review the influences of anterior disc displacement on oral mandibular function and morphology and their biological mechanisms. PMID:26980658

  14. An analysis of acromioclavicular joint morphology as a factor for shoulder impingement syndrome

    PubMed Central

    Tavakkolizadeh, Adel; Sinha, Joydeep

    2014-01-01

    Background The present study aimed to determine whether acromioclavicular (AC) joint morphology was a factor in the development of symptomatic impingement necessitating AC joint excision. Methods We performed a prospective cohort study on all patients undergoing AC joint excision for symptomatic joint pain unresponsive to conservative treatment between 2009 and 2011. This involved 106 consecutive patients (57 women, 49 men, average age 54 years, age range 33 to 76 years). Prior to surgery, radiographic classification of the AC joint was performed producing three main groups: oblique, flat or curved. Pre- and postoperative assessment was performed using the Oxford Shoulder Score and the Disabilities of the Arm, Shoulder and Hand questionnaire. Results A significantly (p < 0.05) higher frequency of oblique AC joint morphology was seen in the AC joint excision study population compared to the normal population. Postoperative outcome demonstrated no significant difference (P > 0.05) between any of the three AC joint morphologies. Conclusions The present study demonstrates a significant association between the oblique AC joint morphology and those patients who develop AC joint pain requiring surgery. Outcomes of surgery were independent of joint morphology, gender or age, with all patient subgroups demonstrating significant improvement by the end of the study.

  15. What psychosocial factors influence adolescents' oral health?

    PubMed

    Baker, S R; Mat, A; Robinson, P G

    2010-11-01

    Few studies have examined, comprehensively and prospectively, determinants of oral-health-related quality of life. The aim of this study was to examine the relationships between psychosocial factors and oral health status, health perceptions, and quality of life. Measures of symptom and functional status, health perceptions, quality of life, oral health beliefs, and psychological (sense of coherence, self-esteem, health locus of control) and social factors (parents' income and education) were collected from 439 12- and 13-year-olds at baseline and six-month follow-up, together with a clinical examination at baseline. Structural equation modeling indicated that increased levels of caries and more symptoms predicted more functional limitations, and, cross-sectionally, greater functional impact was associated with worse health perceptions, which were linked to lower quality of life. Sense of coherence was the most important psychosocial predictor. These factors are important in understanding how oral health affects young people's daily lives. PMID:20739689

  16. Computational analysis of nonlinear creep of polyphase aggregates: Influence of phase morphology

    NASA Astrophysics Data System (ADS)

    Cook, A. C.; Vel, S. S.; Gerbi, C.; Johnson, S. E.

    2014-09-01

    The constitutive laws of polyphase aggregates dominantly depend on the operative deformation mechanisms, phase morphology and modes, and environmental conditions. Each of these factors has the potential to dramatically affect bulk mechanical properties as well as the local stress and strain rate distributions. To focus on the effects of phase morphology, we have developed a rigorous multiscale approach based on asymptotic expansion homogenization. The proposed methodology has two fundamental goals: (1) accurately predict bulk behavior in aggregates by explicitly taking into account phase morphology and (2) calculate detailed distributions of strain rates, stresses, and viscosities in heterogeneous materials. The methodology is able to consider general nonlinear phase constitutive laws that relate strain rates to stresses, temperature, and other factors such as water fugacity and grain size. We demonstrate the approach by analyzing power law creep of computer-generated and natural polyphase systems and benchmarking the results against analytical solutions. As an outcome of this analysis, we find that the approximation of an aggregate as a power law material is reasonable for isotropic, homogeneous phase distributions but breaks down significantly with high degrees of phase organization. We also present distributions in strain rate, stress, and viscosity for different applied loading conditions. Results exhibit areas of high internal stresses and substantial localization. We describe and provide a freely available software package supporting these calculations.

  17. Factors Influencing the Elimination of Dietary Restraint.

    ERIC Educational Resources Information Center

    Herman, C. Peter; Polivy, Janet

    Recent research by Herman, Polivy, and their colleagues has been concerned with the determinants of self-control and disinhibition in dieters. The present paper summarizes a number of studies in which the reactions of dieters and nondieters to a variety of disinhibitory factors (preloading, emotional arousal, intoxication) were investigated. The…

  18. Factors Influencing Recruitment in Educational Psychology

    ERIC Educational Resources Information Center

    Frederickson, Norah

    2003-01-01

    This paper reports an investigation of the factors that educational psychologists in training (EPiTs) look for when applying for jobs in educational psychology services. Relevant literature on "job attraction" is reviewed and a three-stage research process employed. This involved a focus group approach to questionnaire generation followed by…

  19. 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…

  20. 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…

  1. Environmental factors influencing growth and pubertal development.

    PubMed Central

    Delemarre-van de Waal, H A

    1993-01-01

    Postnatal growth is based on hereditary signals and environmental factors in a complex regulatory network. Each factor must be in an optimal state for normal growth of the child. Fetal conditions may also have consequences on postnatal height. Intrauterine growth retardation can be recovered postnatally, although postnatal growth remains depressed in about one-third of cases. After birth, the environment may exert either a positive or negative effect on growth. In underdeveloped countries, malnutrition plays a major role in inhibiting the growth process. Children from families of higher socioeconomic classes are taller than their coevals in the lower socioeconomic groups. Urbanization also has a positive effect on growth. Better child care is supported by sufficient food supply, appropriate health and sanitation services, and a higher level of education. Over the last century, these factors have induced a taller stature and a more rapid maturity in Europe, North America, and Australia; a phenomenon which has been referred to as "the secular trend" in growth. Recently, a secular trend has also been reported in some developing countries. Although urbanization in general appears to be associated with better conditions of living, this is not the case in the slums of South America or in Africa where rural children are better off than children living in the poor cities. This paper describes in more detail the different hereditary and environmental factors that act during the fetal period and postnatally, and which play a role in human growth and pubertal development. PMID:8243404

  2. 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. PMID:21998033

  3. 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

  4. 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

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

    PubMed

    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

  6. Neighbor influences on root morphology and mycorrhizal fungus colonization in tallgrass prairie plants

    SciTech Connect

    Jastrow, J.D. Univ. of Illinois, Chicago ); Miller, R.M. )

    1993-03-01

    A field study was conducted across a chronosequence of tallgrass prairie restorations to investigate the influence a plant's neighbor may have on its gross root morphology and association with mycorrhizal fungi. The root systems of a warm-season grass, Andropogon gerardii, and two perennial forbs, Coreopsis tripteris and Solidago altissima, were sampled by excavating soil blocks representing all pairwise inter- and intra-specific combinations of these species. With forb neighbors, Andropogon had higher percentages of its firbrous roots colonized by mycorrhizal fungi than with conspecific neighbors. Andropogon root morphology (as measured by average root radius, specific root length, and root branching) did not vary with neighbor growth form; however, Andropogon roots did become finer as restoration age and root densities increased. For Coreopsis and Solidago, colonization of fibrous roots did not vary with neighbor species, but both forbs had coarser roots with interspecific neighbors than with conspecifics. With interspecific neighbors, Coreopsis almost doubled the number of branches per centimetre of root observed in conspecific pairs. Although some of the variations in colonization and root morphology may be attributable specifically to neighbor root mass, others were related to the overall root mass of the target-neighbor pair. The observed variations in mycorrhizal colonization may be related to increased opportunities for colonization by the fungus that are due not only to higher root densities but also to some sort of interaction between the root systems of Andropogon and the forbs. 44 refs., 2 figs., 2 tabs.

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

    PubMed

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

    2014-10-01

    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 characterize 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

  8. 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

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

    PubMed

    Sicuro, Fernando L; 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 PM(4) 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

  10. Roughness and morphology of composites: influence of type of material, fluoride solution, and time.

    PubMed

    de Oliveira, Ana Luísa Botta Martins; Giro, Elisa Maria Aparecida; Garcia, Patrícia Petromilli Nordi Sasso; Campos, Juliana Álvares Duarte Bonini; Phark, Jin-Ho; Duarte, Sillas

    2014-10-01

    This study evaluated the effect of fluoride solutions on surface roughness and morphology of composites in the short and long term. Specimens were randomly assigned to experimental groups (n=5) according to type of composite (nanofilled, microhybrid, microfilled) and immersion media (artificial saliva, 0.05% sodium fluoride solution, Fluordent Reach, Oral-B, and Fluorgard). Roughness was evaluated at time intervals: T 0 after 24 h in artificial saliva (baseline); T 60 after being in assigned immersion media for 1 min daily over 60 days; and T final after artificial aging (20,000 thermal cycles, 1,200,000 mechanical loading cycles, and continuous immersion for 1,825 min). Surface morphology was qualitatively analyzed by scanning electron microscopy (SEM) at T 60 and T final. Roughness data were submitted to analysis of variance for mixed repeated measures, Sidak, and Tukey tests at α=0.05. Micro-filled resin showed the highest roughness values. Fluoride solutions had no influence on roughness. Higher roughness values were observed after artificial aging. In SEM observations after the artificial aging, the specimens showed surface degradation, irrespective of immersion medium or type of composite. Nano-filled resin showed higher loss of resin matrix and protrusion of filler particles. Roughness was not influenced by fluoride solutions; however, it is material dependent and increases over time. PMID:25115976

  11. 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.

  12. 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

  13. Several efficiency influencing factors in CdTe/CdS solar cells

    SciTech Connect

    Li, K. |; Feng, Z.C. |; Wee, A.T.S.

    1998-12-31

    Several efficiency influencing factors in MOCVD-grown CdTe/CdS solar cells, including preferential crystal orientation of CdTe layers, CdTe grain size and surface roughness, interfacial mixing, and surface and interface geometrical morphology, are studied. X-ray diffraction (XRD) shows that polycrystalline CdTe/CdS solar cells with higher efficiencies tend to have more (111) planes of CdTe parallel to the macro-surface. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis reveal the relationship between the grain size/surface roughness and cell efficiency. Secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES) depth profiling show that the interfacial geometrical morphology has a significant influence on the efficiency of CdTe/CdS solar cells. Finally it is shown that interfacial mixing reduces the number of interfacial states and recombination centers and the energy loss due to internal reflectance, enhancing the performance of the solar cells.

  14. Factors influencing the intensity of magnetospheric substorms

    NASA Technical Reports Server (NTRS)

    Mcpherron, R. L.; Baker, D. N.

    1993-01-01

    A definition of the substorm is presented, and it is shown that the typical isolated substorm is produced by the superposition of effects of processes directly driven by the solar wind through dayside reconnection and those driven by unloading through nighttime reconnection. The single factor that determines whether a substorm will occur or not is the clock angle of the interplanetary magnetic field (IMF) around the earth-sun line. Only when this field points south of the GSM equatorial plane do the auroral electrojet indices depart from their quiet values. For a given clock angle, the level of activity increases with the IMF strength and solar wind velocity.

  15. Factors Influencing Childhood Immunization in Uganda

    PubMed Central

    2013-01-01

    This paper investigates the factors associated with childhood immunization in Uganda. We used nationally-representative data from Uganda Demographic and Health Survey (UDHS) of 2006. Both bivariate and multivariate approaches were employed in the analysis. The bivariate approach involved generating average percentages of children who were immunized, with analysis of pertinent background characteristics. The multivariate approach involved employing maximum likelihood probit technique and generating marginal effects to ascertain the probability of being immunized, given the same background characteristics. It revealed that slightly over 50% of children in Uganda were fully immunized. Additionally, 89%, 24%, 52%, and 64% received BCG, DPT, polio and measles vaccines respectively. Factors which have a significant association with childhood immunization are: maternal education (especially at post-secondary level), exposure to media, maternal healthcare utilization, maternal age, occupation type, immunization plan, and regional and local peculiarities. Children whose mothers had post-secondary education were twice as likely to be fully immunized compared to their counterparts whose mothers had only primary education (p<0.01). Thus, gender parity in education enhancement efforts is crucial. There is also a need to increase media penetration, maternal healthcare utilization, and to ensure parity across localities and regions. PMID:23617212

  16. Factors influencing childhood immunization in Uganda.

    PubMed

    Bbaale, Edward

    2013-03-01

    This paper investigates the factors associated with childhood immunization in Uganda. We used nationally-representative data from Uganda Demographic and Health Survey (UDHS) of 2006. Both bivariate and multivariate approaches were employed in the analysis. The bivariate approach involved generating average percentages of children who were immunized, with analysis of pertinent background characteristics. The multivariate approach involved employing maximum likelihood probit technique and generating marginal effects to ascertain the probability of being immunized, given the same background characteristics. It revealed that slightly over 50% of children in Uganda were fully immunized. Additionally, 89%, 24%, 52%, and 64% received BCG, DPT, polio and measles vaccines respectively. Factors which have a significant association with childhood immunization are: maternal education (especially at post-secondary level), exposure to media, maternal healthcare utilization, maternal age, occupation type, immunization plan, and regional and local peculiarities. Children whose mothers had post-secondary education were twice as likely to be fully immunized compared to their counterparts whose mothers had only primary education (p < 0.01). Thus, gender parity in education enhancement efforts is crucial. There is also a need to increase media penetration, maternal healthcare utilization, and to ensure parity across localities and regions. PMID:23617212

  17. Factors influencing the spinal motoneurons in development

    PubMed Central

    Wiese, Stefan

    2015-01-01

    The development of the spinal cord needs a concerted interaction of transcription factors activating diverse genes and signals from outside acting on the specification of the different cells. Signals have to act on the segments of the embryo as well as on the cranial-caudal axis and the dorso-ventral axis. Additionally the axons of the motoneurons have to cross the central nervous system barrier to connect to the periphery. Intensive anatomical studies have been followed by molecular characterization of the different subsets of transcription factors that are expressed by cells of the developing spinal cord. Here, intensive studies for the most important appearing cells, the motoneurons, have resulted in a good knowledge on the expression patterns of these proteins. Nonetheless motoneurons are by far not the only important cells and the concert activity of all cells besides them is necessary for the correct function and integrity of motoneurons within the spinal cord. This article will briefly summarize the different aspects on spinal cord development and focuses on the differentiation as well as the functionalization of motoneurons. PMID:26807112

  18. 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

  19. Influence of Rheological and Thermal Properties of Polymers During Melt Spinning on Bicomponent Fiber Morphology

    NASA Astrophysics Data System (ADS)

    Ayad, Esma; Cayla, Aurélie; Rault, François; Gonthier, Anne; LeBlan, Thierry; Campagne, Christine; Devaux, Eric

    2016-06-01

    Microfibers can be obtained by bicomponent spinning, followed by subsequent mechanical splitting. During process, two materials are coextruded in a die to form a unique complex morphology. Many factors affect these morphologies: melt viscosity and difference of crystallization temperature combined with polymers position. Consequently, fiber splitting can be improved by choosing an association of polymers with a stable interface and a poor adhesion. The aim of this study is to understand which intrinsic parameters of polymers allow to enhance bicomponent fiber's splitting. Bicomponent fibers (side-by-side and sheath/core) have been made with two grades of polypropylene and polyamide 6. Instable interface happens when a low-viscosity polymer flows around and encapsulates a high-viscosity material. Possible mechanism responsible of interface deformation is variation of shear rates through the morphology (highest shear rate is at the fiber periphery). DMA analysis reveals that fiber with polyamide as core exceeds the strength of fiber with polyamide as sheath. This increase of strength can be attributed to a better adhesion than fibers with PA6 in sheath. From experimental results, the position combined with the difference crystallization temperature shows poor or strong interface.

  20. 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. PMID:22559697

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

    NASA Astrophysics Data System (ADS)

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

    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.

  2. Factors influencing whether children walk to school.

    PubMed

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

    2013-07-01

    Few studies have simultaneously evaluated multiple levels of influence on whether children walk to school. A large cohort of 4338 subjects from 10 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

  3. 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

  4. 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

  5. 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

  6. Partial purification and characterization of an escherichia coli toxic factor that induces morphological cell alterations.

    PubMed Central

    Caprioli, A; Falbo, V; Roda, L G; Ruggeri, F M; Zona, C

    1983-01-01

    A factor produced by several strains of Escherichia coli isolated from enteritis-affected children has been shown to produce both a necrotizing effect on rabbit skin and striking morphological alterations on CHO, Vero, and HeLa cells. The same strains were found to have hemolytic activity on sheep erythrocytes. The toxic, cell-altering factor was demonstrated to be different from both heat-labile and heat-stable enterotoxins and from Vero toxin. The main effect induced by the isolated factor on cultured cells was the formation of large multinucleated cells. The partial purification achieved suggests that the same factor (most likely a protein with a molecular weight of 70,000 to 80,000) is responsible for toxic and cell-altering activities, whereas a different molecular species is responsible for hemolytic activity. Images PMID:6341235

  7. Breast cancer diagnosis and factors influencing treatment decisions in Ghana.

    PubMed

    Aziato, Lydia; Clegg-Lamptey, Joe Nat A

    2015-01-01

    Researchers in this study explored the reactions of women with breast cancer and identified factors influencing treatment decisions. A qualitative exploratory approach was employed. Participants were recruited from a tertiary hospital and a breast cancer support group. Purposive sampling recruited 12 women. It was found that women identified breast lesions accidentally or intentionally and that diagnosis was delayed. Emotional reactions to diagnosis included shock and sadness. Factors that influenced treatment were the influence of other people, alternative sources of treatment, faith and support, knowledge, "tuning the mind," and effects on intimacy. Health professionals should develop effective communication and counseling skills for clients. PMID:24750095

  8. Factors influencing single mother's employment status.

    PubMed

    Youngblut, J M; Brady, N R; Brooten, D; Thomas, D J

    2000-03-01

    Changes in the welfare system limit the length of time a person can receive welfare benefits, thus mandating employment for many current welfare recipients. Single mothers with young children who do not become employed will lose financial support for housing, food, clothing, and health care and place their own and their children's health and safety at risk. The purpose of this qualitative study was to explore women's experiences of being unemployed and to examine the barriers to employment perceived by single mothers who expressed a desire to be employed. Nine mothers were recruited from a larger sample of single mothers who had participated in a quantitative study about employment conducted 1 to 2 years earlier. Using focus group interviews, mothers were asked what it was like to be a single mother, and then what barriers to their employment they perceived. Two dimensions were identified from the mothers' statements. The first, a sense of obligation, included themes of "being there" for their own and their child's benefit and doing what it takes to optimize the child's growth and development. The second, negotiating the obstacles, referred to problems regarding child care, lack of involvement of the child's father and lack of support from relatives and friends for the mother's efforts toward securing employment. These findings have important implications for welfare reform, namely, that efforts aimed at moving nonemployed single mothers into the workforce will fail if these factors are not considered. PMID:10818834

  9. 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

  10. 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. PMID:25483789

  11. 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

  12. 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…

  13. 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).…

  14. 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…

  15. Factors Influencing Students' Achievement in Form 5 Islamic Studies Subject

    ERIC Educational Resources Information Center

    bin Che Noh, Mohd Aderi; Omar, Noraini binti; bin Kasan, Hasnan

    2013-01-01

    This study is aimed at analyzing the factors influencing the achievements of students in the subject of Islamic Studies for Form 5 SPM (KBSM) in schools in the area of Samarahan, Sarawak. The factors analysed is attitude and interest. This is a survey based study and data was compiled from the survey forms which had the topic "Factors…

  16. Factors Influencing Pursuit of Higher Education: Validating a Questionnaire.

    ERIC Educational Resources Information Center

    Harris, Sandra M.

    This paper explains the process used to validate the construct validity of the Factors Influencing Pursuit of Higher Education Questionnaire. This questionnaire is a literature-based, researcher-developed instrument which gathers information on the factors thought to affect a person's decision to pursue higher education. The questionnaire includes…

  17. Factors influencing visits to school nurses by pregnant adolescents.

    PubMed

    Chen, S P; Telleen, S; Mitchell, D R; Chen, E H

    1992-01-01

    The influence of five factors on the first visit to school nurses by pregnant adolescents and adequacy of prenatal care was analyzed. Only one factor, age of baby's father, was found to be associated with adequacy of prenatal care. PMID:1518672

  18. 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…

  19. Factors Influencing International Students' Career Choice: A Comparative Study

    ERIC Educational Resources Information Center

    Singaravelu, Hemla D.; White, Lyle J.; Bringaze, Tammy B.

    2005-01-01

    This study examines the career development behavior of Asian international, non-Asian international, and domestic students, specifically the certainty of career and major choice and environmental factors that have influenced their choices. Environmental factors include family, school counselors, teacher, friends, and government. The results show…

  20. 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…

  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. Factors Influencing Psychological Help Seeking in Adults: A Qualitative Study

    ERIC Educational Resources Information Center

    Topkaya, Nursel

    2015-01-01

    The aim of the current research is to identify which factors, and in what direction these factors influence adults' decisions to seek psychological help for their personal problems. The research was designed as a phenomenology model; the data was gathered through the semi-structured interview technique, which is mostly used in qualitative research…

  3. How Riparian Vegetation Influences Stream Morphology and Process: Implications for Restoration

    NASA Astrophysics Data System (ADS)

    Pizzuto, J. E.

    2005-05-01

    Vegetation is often used to enhance bank stabilization efforts and as part of more generalized restoration designs, but the influence of vegetation on geomorphic processes is poorly understood. Recent research suggests that changes in riparian vegetation can influence channel morphology, rates of erosion and deposition, and by extension, the entire sediment budget of a reach. In recent studies in the Mid-Atlantic region, reaches with forested riparian vegetation were compared to immediately adjacent non-forested (grassy) riparian vegetation to explain why channels with forested vegetation are wider than their non-forested counterparts. At study sites, erosion occurs at cutbanks in curving reaches, while deposition is localized on active floodplains at the insides of bends. In narrow, non-forested reaches, rates of bank erosion and channel migration are high, while in wide, forested reaches, rates of bank erosion and channel migration are low. These results may be explained using the ratio of two dimensionless parameters, alpha and E. Alpha represents the influence of vegetation on rates of active floodplain deposition (it is very high in non-forested reaches, and very low in forested reaches), while E is proportional to rates of cutbank migration (it is high in non-forested areas and low in forested areas). The width is proportional to E/alpha. These results could lead to improved assessment of the geomorphic effects of restoration designs that involve changes in riparian vegetation.

  4. A Genome-Wide Association Study Identifies Five Loci Influencing Facial Morphology in Europeans

    PubMed Central

    Liu, Fan; van der Lijn, Fedde; Schurmann, Claudia; Zhu, Gu; Chakravarty, M. Mallar; Hysi, Pirro G.; Wollstein, Andreas; Lao, Oscar; de Bruijne, Marleen; Ikram, M. Arfan; van der Lugt, Aad; Rivadeneira, Fernando; Uitterlinden, André G.; Hofman, Albert; Niessen, Wiro J.; Homuth, Georg; de Zubicaray, Greig; McMahon, Katie L.; Thompson, Paul M.; Daboul, Amro; Puls, Ralf; Hegenscheid, Katrin; Bevan, Liisa; Pausova, Zdenka; Medland, Sarah E.; Montgomery, Grant W.; Wright, Margaret J.; Wicking, Carol; Boehringer, Stefan; Spector, Timothy D.; Paus, Tomáš; Martin, Nicholas G.; Biffar, Reiner; Kayser, Manfred

    2012-01-01

    Inter-individual variation in facial shape is one of the most noticeable phenotypes in humans, and it is clearly under genetic regulation; however, almost nothing is known about the genetic basis of normal human facial morphology. We therefore conducted a genome-wide association study for facial shape phenotypes in multiple discovery and replication cohorts, considering almost ten thousand individuals of European descent from several countries. Phenotyping of facial shape features was based on landmark data obtained from three-dimensional head magnetic resonance images (MRIs) and two-dimensional portrait images. We identified five independent genetic loci associated with different facial phenotypes, suggesting the involvement of five candidate genes—PRDM16, PAX3, TP63, C5orf50, and COL17A1—in the determination of the human face. Three of them have been implicated previously in vertebrate craniofacial development and disease, and the remaining two genes potentially represent novel players in the molecular networks governing facial development. Our finding at PAX3 influencing the position of the nasion replicates a recent GWAS of facial features. In addition to the reported GWA findings, we established links between common DNA variants previously associated with NSCL/P at 2p21, 8q24, 13q31, and 17q22 and normal facial-shape variations based on a candidate gene approach. Overall our study implies that DNA variants in genes essential for craniofacial development contribute with relatively small effect size to the spectrum of normal variation in human facial morphology. This observation has important consequences for future studies aiming to identify more genes involved in the human facial morphology, as well as for potential applications of DNA prediction of facial shape such as in future forensic applications. PMID:23028347

  5. Factors influencing nursing career choices and choice of study program.

    PubMed

    Haron, Yafa; Reicher, Sima; Riba, Shoshana

    2014-01-01

    In advance of a recruitment campaign, Israeli first-year nursing students of all ethnicities were surveyed to elucidate what factors had influenced them to make nursing their career and what sort of training track they preferred. The responses made it clear that different factors influence different groups differently. There were noticeable differences by gender, age, and ethnicity. Overall, training institutions were chosen for their closeness to the student's home but other factors also operated among particular groups, such as institutional prestige and flexible entry criteria. There was a blatant preference for academic, particularly university-sited, programs over diploma programs. PMID:24878405

  6. 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

  7. 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. PMID:26035010

  8. Fibroblast growth factor 23 signaling in hippocampal cells: impact on neuronal morphology and synaptic density.

    PubMed

    Hensel, Niko; Schön, Anne; Konen, Timo; Lübben, Verena; Förthmann, Benjamin; Baron, Olga; Grothe, Claudia; Leifheit-Nestler, Maren; Claus, Peter; Haffner, Dieter

    2016-06-01

    Endocrine fibroblast growth factor 23 (FGF23) is predominantly secreted by osteocytes and facilitates renal phosphate excretion. However, FGF23 is also present in cerebrospinal fluid. In chronic kidney disease, FGF23 serum levels are excessively elevated and associated with learning and memory deficits. Structural plasticity of the hippocampus such as formation of new synapses or an altered dendritic arborization comprises a cellular and morphological correlate of memory formation. Therefore, we hypothesize that FGF23 alters hippocampal neuron morphology and synapses. To address this, we prepared primary murine hippocampal cultures and incubated them with recombinant FGF23 alone or together with a soluble isoform of its co-receptor α-Klotho. Neuronal expression of a fluorescent reporter allowed for a detailed evaluation of the neuronal morphology by Sholl analysis. Additionally, we evaluated synaptic density, identified by stainings, for synaptic markers. We show an enhanced number of primary neurites combined with a reduced arborization, resulting in a less complex morphology of neurons treated with FGF23. Moreover, FGF23 enhances the synaptic density in a FGF-receptor (FGF-R) dependent manner. Finally, we addressed the corresponding signaling events downstream of FGF-R employing a combination of western blots and quantitative immunofluorescence. Interestingly, FGF23 induces phospholipase Cγ activity in primary hippocampal neurons. Co-application of soluble α-Klotho leads to activation of the Akt-pathway and modifies FGF23-impact on neuronal morphology and synaptic density. Compared with other FGFs, this alternative signaling pattern is a possible reason for differential effects of FGF23 on hippocampal neurons and may thereby contribute to learning and memory deficits in chronic kidney disease patients. In this study, we show that fibroblast growth factor 23 inhibits neuronal ramification and enhances the synaptic density in primary hippocampal cultures

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

    PubMed

    Gnanaprakasam Thankam, Finosh; Muthu, Jayabalan

    2014-11-01

    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. PMID:25129740

  10. Influence of calcium precursors on the morphology and crystallinity of sol gel-derived hydroxyapatite nanoparticles

    NASA Astrophysics Data System (ADS)

    Vijayalakshmi Natarajan, U.; Rajeswari, S.

    2008-10-01

    Nanosized hydroxyapatite (HAP) particles were prepared by sol-gel method from the water-based solution of calcium and phosphorus precursor. In this study, two calcium precursors such as calcium nitrate tetrahydrate and calcium acetate were chosen as calcium precursors. The influence of aging period, pH, viscosity and sintering temperature on crystallinity and morphology of the HAP particles were investigated for the two calcium precursors with triethyl phosphate precursor. The morphology of nano-HAP towards phosphorous precursor was dependent on the type of calcium precursor used. The HAP prepared from calcium nitrate and triethyl phosphate was spherically shaped whereas the one from calcium acetate was found to be fibrous in structure. Both HAPs were stable up to 1200 °C and their crystallinity increased with respect to the sintering temperature. The obtained sample was characterized through X-ray diffraction (XRD), P 31 nuclear magnetic resonance (NMR), scanning electronic microscopy (SEM) and TEM analysis. The sol derived from the optimized aging period for the two different calcium precursors was coated on 316L stainless-steel (SS) implant and its corrosion resistivity during long-term implantation was studied by cyclic polarization in Ringer's solution. Both HAPs have their own desirable qualities and were found to be corrosion resistive.

  11. 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.

  12. 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. PMID:26429581

  13. 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

  14. 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.

  15. Boarding school influence on self-reported concern for perceived body and face morphology in Taiwan.

    PubMed

    Chang, Chieh Ting; Garg, Prerna; Giddon, Donald B

    2016-08-01

    To determine the influence of boarding school on self-perceived body and facial morphology, the Body Shape Questionnaire (BSQ) and exploratory questions about the orofacial area (OFA) were administered to female boarding (B) and nonboarding (NB) students at two Catholic schools in Taiwan. The mean total BSQ scores of Bs were significantly higher than NBs, with both being significantly higher than the published normative score but lower than probable bulimics with no significant B vs. NB difference in mean total OFA scores. Because the Bs were significantly taller and reported more orthodontic treatment than NBs, the possible confounding by the higher economic status of the Bs was minimized by finding similar significantly higher BSQ scores for the small number of Bs (5%) than the remaining NBs (95%) in the documented lower socio-economic school. In summary, the experience of boarding in religion-dominated schools significantly increases body image concerns of adolescent females. PMID:27520907

  16. Influence of Surface Morphology on the Torsion Fracture of NiTi Endodontic Instruments

    NASA Astrophysics Data System (ADS)

    Elias, Carlos; Lopes, Helio; Vieira, Victor; Souza, Leticia; Vieira, Márcia

    2014-07-01

    This study analyzed the influences of manufacturing process (twisting and machining) and surface finishing on the angular distortion, maximum torque, and toughness of two NiTi endodontic instruments (Race—FKG Dentaire and TF—Twisted Files, SybronEndo). Statistical analysis of results showed that TF instruments (twisted) had higher distortion angle ( p < 0.05) and lower maximum torque to fracture ( p < 0.05) than Race instruments (machined). SEM analysis of fractured instruments showed a surface morphology characteristic of ductile fracture, with plastic deformation in the helical shafts. The results suggest that both instruments are equally suitable for clinical applications. This study is purely scientific as it evaluates only some material properties, and is not intended to endorse a commercial product.

  17. 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

  18. 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

    2016-01-01

    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

  19. 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. PMID:26646111

  20. 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. PMID:20041792

  1. 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. PMID:26775077

  2. Factors That Influence the Practice of Elective Induction of Labor

    PubMed Central

    Moore, Jennifer; Low, Lisa Kane

    2012-01-01

    Elective induction of labor has been linked to increased rates of prematurity and rising rates of cesarean birth. The purpose of this investigation was to evaluate current trends in induction of labor scholarship focusing on evidence-based factors that influence the practice of elective induction. A key word search was conducted to identify studies on the practice of elective induction of labor. Analysis of the findings included clustering and identification of recurrent themes among the articles with 3 categories being identified. Under each category, the words/phrases were further clustered until a construct could be named. A total of 49 articles met inclusion criteria: 7 patient, 6 maternity care provider, and 4 organization factors emerged. Only 4 of the articles identified were evidence based. Patient factors were divided into preferences/convenience, communication, fear, pressure/influence, trust, external influences, and technology. Provider factors were then divided into practice preferences/convenience, lack of information, financial incentives, fear, patient desire/demand, and technology. Organization factors were divided into lack of enforcement/accountability, hospital culture, scheduling of staff, and market share issues. Currently, there is limited data-based information focused on factors that influence elective induction of labor. Despite patient and provider convenience/preferences being cited in the literature, the evidence does not support this practice. PMID:22843006

  3. 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.

  4. Influence of Surface Morphology on the Shear-Induced Wear of Alkylsilane Monolayers: Molecular Dynamics Study.

    PubMed

    Summers, Andrew Z; Iacovella, Christopher R; Billingsley, Matthew R; Arnold, Steven T; Cummings, Peter T; McCabe, Clare

    2016-03-15

    Chemisorbed alkylsilane monolayer coatings have been shown to possess favorable lubrication properties; however, film degradation prevents the widespread use of these materials as lubricants in micro- and nanoelectromechanical systems (MEMS/NEMS). In this work, molecular dynamics (MD) simulations are used to provide insight into the conditions that promote the degradation and wear of these materials. This is achieved through removal of interfacial chain-substrate bonds during shear and the examination of the mobility of the resulting free, unbound chains. Specific focus is given to the effects of surface morphology, which has been shown previously to strongly influence frictional forces in monolayer systems. In-plane order of chain attachments is shown to lead to pressure-induced orientational ordering of monolayers, promoting film stability. This behavior is lost as nonideality is introduced into the substrate and chain patterning on the surface becomes disordered. The presence of surface roughness is found to reduce film stability, with localization of wear observed for chain attachment sites nearest the interface of contact. The influence of substrate nonideality on monolayer degradation is shown to diminish as chain length is increased. PMID:26885941

  5. Hydrogeologic factors affecting cavern morphology within rocks of Mississippian age in northwestern Arkansas

    SciTech Connect

    Fanning, B.J. . Dept. of Geology); Brahana, J.V. . Geological Survey)

    1993-02-01

    Cavern development within rocks of Mississippian age in northwestern Arkansas is associated with two Pleistocene erosional features, the Boston Mountains Plateau and the Springfield Plateau. Each plateau is characterized by a distinct stratigraphic sequence with unique lithologies. Cavern morphology (both cross-sectional and planimetric) in each plateau is the result of the complex interaction of numerous hydrogeologic factors. Four of the most dominant factors which affect cavern morphology appear to be: (1) composition and continuity of the confining units; (2) percentage of noncarbonate components in rocks of the cavern-forming interval; (3) nature and distribution of ground-water recharge to the cavern-forming interval; and (4) nature and distribution of fractures within the cavern-forming interval. Network maze patterns typically develop in the Pitkin Limestone, the formation in which most caverns form beneath the Boston Mountains Plateau. The Pitkin, a bioclastic limestone, is confined above by siltstones of the Cane Hill member of the Hale Formation and below by shales of the Fayetteville Formation. The maze pattern indicates that these caverns probably were formed by dissolution of the rock matrix by diffuse recharge moving vertically through leaky confining units. Single rooms are the dominant cavern morphology in the chert-dominated Boone Formation of the Springfield Plateau. Where the concentration of chert is greater than 50 percent, the Boone lacks structural integrity and fails to develop well-integrated conduit networks. Point recharge features in outcrop areas of the Boone Formation are not visible in most of the Springfield Plateau because the insoluble residuum masks the upper bedrock surface. Where the Boone Formation is less than 7 meters thick, surface karst features are more prevalent.

  6. Influence analysis for the factor analysis model with ranking data.

    PubMed

    Xu, Liang; Poon, Wai-Yin; Lee, Sik-Yum

    2008-05-01

    Influence analysis is an important component of data analysis, and the local influence approach has been widely applied to many statistical models to identify influential observations and assess minor model perturbations since the pioneering work of Cook (1986). The approach is often adopted to develop influence analysis procedures for factor analysis models with ranking data. However, as this well-known approach is based on the observed data likelihood, which involves multidimensional integrals, directly applying it to develop influence analysis procedures for the factor analysis models with ranking data is difficult. To address this difficulty, a Monte Carlo expectation and maximization algorithm (MCEM) is used to obtain the maximum-likelihood estimate of the model parameters, and measures for influence analysis on the basis of the conditional expectation of the complete data log likelihood at the E-step of the MCEM algorithm are then obtained. Very little additional computation is needed to compute the influence measures, because it is possible to make use of the by-products of the estimation procedure. Influence measures that are based on several typical perturbation schemes are discussed in detail, and the proposed method is illustrated with two real examples and an artificial example. PMID:18482479

  7. 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.

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

    PubMed

    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

  9. 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

  10. 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…

  11. 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…

  12. 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…

  13. Factors Influencing Adjustment to Late-Life Divorce.

    ERIC Educational Resources Information Center

    Wilson, Keren Brown; DeShane, Michael R.

    Although the rate of divorce among older Americans has increased steadily, little attention has been paid to late life divorce. To describe the role of age and other factors which might influence adjustment to divorce in later life, data from a larger pilot study were used: 81 divorced persons over the age of 60 completed in-depth, structured…

  14. FACTORS INFLUENCING FALL FOLIAGE COLOR EXPRESSION IN SUGAR MAPLE TREES.

    EPA Science Inventory

    Abstract: We evaluated factors influencing red autumn coloration in leaves of sugar maple (Acer saccharum Marsh.) by measuring mineral nutrition and carbohydrate concentrations, moisture content, and phenology of color development of leaves from 16 mature open-grown trees on 12 d...

  15. Improving Performance Appraisals: Confronting Subjective Factors That Influence Ratings.

    ERIC Educational Resources Information Center

    Kruger, Michael J.

    1986-01-01

    Explores implications of subjective factors that influence rating processes upon which formal performance appraisal systems are based and presents a strategy for addressing this problem which utilizes the critical incident method to focus objectively on employee behavior. A performance feedback worksheet to be utilized with this appraisal method…

  16. Factors that Influence Informal Learning in the Workplace

    ERIC Educational Resources Information Center

    Berg, Shelley A.; Chyung, Seung Youn

    2008-01-01

    Purpose: The purpose of this research is to investigate factors that influence informal learning in the workplace and the types of informal learning activities people engage in at work. More specifically, the research examined: the relationship between informal learning engagement and the presence of learning organization characteristics; and…

  17. 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.…

  18. Key Factors that Influence Recruiting Young Chinese Students

    ERIC Educational Resources Information Center

    Wang, Zhenmin

    2007-01-01

    The discussion in this paper is based on the assumption that international education is equated to recruiting and educating international students, even though its true concept goes far beyond this narrow understanding. The purpose of this research is to look at the key factors that influence recruiting young Chinese students, and make sure all…

  19. 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.…

  20. 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…

  1. 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…

  2. 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…

  3. Factors That Influence the Understanding of Good Mathematics Teaching

    ERIC Educational Resources Information Center

    Leong, Kwan Eu

    2013-01-01

    This study explored the factors that influenced the understanding of good mathematics teaching. A mixed methodology was used investigate the beliefs of beginning secondary teachers on good mathematics teaching. The two research instruments used in this study were the survey questionnaire and an interview. Beginning teachers selected Immediate…

  4. Factors Influencing Students' Decisions about Post-Year 10 Education

    ERIC Educational Resources Information Center

    Beswick, Kim; Hay, Ian; Watson, Jane; Allen, Jeanne; Cranston, Neil

    2012-01-01

    This paper reports pilot data from an instrument devised as part of a large ARC funded project that aims, among other things, to investigate factors that influence the decisions of students in rural and/or disadvantaged areas to continue their schooling beyond Year 10. One section of the pilot student questionnaire comprised 42 items designed to…

  5. Factors Influencing the Dielectric Properties of Agricultural and Food Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dielectric properties of materials are defined, and the major factors that influence these properties of agricultural and food materials, namely, frequency of the applied radio-frequency or microwave electric fields, and water content, temperature, and density of the materials, are discussed on the ...

  6. 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…

  7. 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…

  8. 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…

  9. Factors Influencing the Vocational Aspirations of Victorian Year 9 Students.

    ERIC Educational Resources Information Center

    Schrom, Linda K.

    A study was conducted to determine the influence of family background and attitudinal factors on occupational aspirations of Year 9 students in Victoria, Australia. A survey was made of all Victorian Year 9 students and comparisons were made between groups of students who aspired to different occupations. Discriminant function analyses were…

  10. Factors Influencing the Readability of Student-Generated Texts.

    ERIC Educational Resources Information Center

    Allen, JoBeth

    An investigation examined student-generated texts in terms of both traditional and more theoretically valid readability to determine what factors influence comprehension when children read their own, peer, and adult-written texts. Seventy dictated stories created in an earlier study, along with 4 first-grade level stories from the "Reader's Digest…

  11. 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,…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. Factors Influencing Knowledge Creation and Innovation in an Organisation

    ERIC Educational Resources Information Center

    Merx-Chermin, Mireille; Nijhof, Wim, J.

    2005-01-01

    Purpose: The purpose of this study is to gain a better understanding of the factors that influence the innovative power of organisations. The concept of innovation and innovative power was examined by analysing the relationship between the construct of the learning organisation, knowledge organisation and innovative organisation, and has resulted…

  18. Police Management Training Factors Influencing DWI Arrests. Final Report.

    ERIC Educational Resources Information Center

    Bishop, Edward W.

    The development of training material for police management personnel concerning command and supervisory actions appropriate for more effective driving-while-intoxicated (DWI) enforcement is desired. The training is based on two research studies that identified environmental and attitudinal factors influencing a patrolman's arrest decision. These…

  19. 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…

  20. 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…

  1. 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…

  2. 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…

  3. Factors Influencing the Adoption of Multimedia Cable Technology.

    ERIC Educational Resources Information Center

    Lin, Carolyn A.; Jeffres, Leo W.

    1998-01-01

    Integrates several mainstream research approaches to new media diffusion to explore the potential strengths and weaknesses of each. Investigates factors influencing multimedia cable service adoption interest, including demographic variables, existing media-use patterns, and personality traits such as "innovativeness." (SR)

  4. Factors Influencing Federal Employee Worker Satisfaction: A Baseline Study.

    ERIC Educational Resources Information Center

    Schmidt, Wallace V.; And Others

    Utilizing data from the Federal Employee Attitude Survey, 1979, a survey was distributed to a stratified random sample of 20,000 employees to identify and analyze the factors influencing federal employee worker satisfaction. Questions on the survey ranged from demographics to personal evaluations of the work environment as recorded on a…

  5. 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…

  6. 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…

  7. 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…

  8. 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…

  9. Factors Influencing Consent for Electronic Data Linkage in Urban Latinos.

    PubMed

    Bakken, Suzanne; Yoon, Sunmoo; Suero-Tejeda, Niurka

    2015-01-01

    Within the context of patient participation in a Learning Health System, this study examined consent rates and factors associated with consent for linking survey data with electronic clinical data in a sample of 2,271 Latinos. Consent rate was 96.3%. Government insurance status and health literacy significantly influenced the odds of consent. PMID:26262286

  10. Factors that Influence Elementary Teachers Use of Computers

    ERIC Educational Resources Information Center

    Franklin, Cheryl

    2007-01-01

    The purpose of this quantitative study was to examine the ways elementary teachers use computer technology for instructional purposes and the factors that influence their use of computers. The population consisted of recent graduates from the elementary teacher preparation program at a mid-Atlantic university. Data were gathered using a survey…