Effect Of Local Variation Research Articles

Spatiotemporal snowmelt patterns within a high Arctic landscape, with implications for flora and fauna

ABSTRACT Snow conditions are important drivers of the distribution and phenology of Arctic flora and fauna, but the extent and effects of local variation in snowmelt are still inadequately studied. We analyze snowmelt patterns within the Zackenberg valley in northeast Greenland. Drawing on landscape-level snowmelt dates and meteorological data from a central climate station, we model snowmelt trends during 1998–2014. We then use time-lapse photographs to examine consistency in spatiotemporal snowmelt patterns during 2006–2014. Finally, we use monitoring data on arthropods and plants for 1998–2014 to investigate how snowmelt date affects the phenology of Arctic organisms. Despite large interannual variation in snowmelt timing, we find consistency in the relative order of snowmelt among sites within the landscape. With a slight overall advancement in snowmelt during the study period, early melting locations have advanced more than late-melting ones. Individual organism groups differ greatly in how their phenology shifts with snowmelt, with much variance attributable to variation in life history and diet. Overall, we note that local variation in snowmelt patterns may drive important ecological processes, and that more attention should be paid to variability within landscapes. Areas optimal for a given taxon vary between years, thereby creating spatial structure in a seemingly uniform landscape.

The effects of local variation in light availability on pollinator visitation, pollen and resource limitation of female reproduction in Hosta ventricosa

BackgroundLight availability may have direct effects on reproduction through resource availability, and indirect effects on female reproduction by influencing plant-pollinator interactions. Floral display size, pollinator visitation per flower, resource and pollen limitation of fruit and seed production were quantified in a forested patch and an adjacent open patch of two populations of the perennial herb Hosta ventricosa.ResultsPlants in the open patch produced significantly larger floral displays than those in the forested patch in both populations. Floral display size had a positive effect on pollinator visitation rate per flower in one population, but no effect in the other. Plants in the open patch received approximately 8–11 times more visitation rates and produced significantly more fruit and seeds per flower than those in the forested patch. However, supplemental pollination resulted in significantly more fruit and seed production per flower compared to natural pollination in the forested patch but not in the open patch in one population, and did not enhance fruit and seed production in either the forested or the open patch in the other. In both populations, supplementally pollinated plants in the open patch produced significantly more fruit and seeds per flower than supplementally pollinated plants in the forested patch.ConclusionsIn H. ventricosa, local variation in light conditions could affect pollinator activity and influence female reproduction through resource availability; however differences in the degree of pollen limitation between local habitats were found to be population-specific.

PREDICTION OF GRAIN GROWTH IN HYBRID WELDING HAZ OF TCS STAINLESS STEEL

According to the formula of grain growth under isothermal condition, the kinetics equation of ferritic grain growth in heat affected zone (HAZ) was obtained, which was combined with the calculated thermal cycles to predict the grain growth in HAZ of TCS stainless steel under the new-type welding procedure-hybrid welding. The grain sizes in HAZ of TCS stainless steel have been calculated for three welding conditions. Simulation results are validated by the average grain sizes measured on the metallographic images of the welding joint of TCS stainless steel. Preliminary discussion has been made on correlation of the grain growth with the thermal cycles and the effect of local variation in thermal cycles on the grain growth.

Undermining Stereotypes of Linguistic Groups Through Mediated Intergroup Contact

The article investigates majority group viewing of minority language media, with a particular focus on examining (a) motivations for viewing, (b) associations between viewing and stereotypes, and (c) the moderating effects of local minority language vitality and direct interpersonal contact. Among Finnish-speaking Finns (the majority group), traditional motivations (e.g., diversion) as well as intergroup motivations (e.g., seeking contact with the outgroup culture) were found to statistically predict Swedish language television viewing, and Swedish language television viewing predicted more positive stereotypes of Swedish-speaking Finns (the minority group). This latter effect was moderated by vitality, such that it was stronger in areas of higher Swedish (outgroup) vitality: The authors had predicted that the effect would be stronger in areas of lower vitality. The results are discussed in terms of intergroup contact theory and the effects of local variation in group vitality on the potential for media to influence intergroup attitudes, including the role of perceived threat from a large local minority population.

Mathematical Modeling of Diffusion Phenomenon in a Moderately Constricted Geometry

The incorporation of fluid flow through modelled normal and stenosed capillary-tissue exchange system has highlighted issues that may have major applications for the study of diffusion phenomenon. Results clearly demonstrate the important roles played by various physiological characteristics and diffusion variables involved in the analysis on blood flow. Assessment of the severity of the disease could be made possible through the variation of a parameter named as retention parameter. An attempt has been made to study the effects of local variation of viscosity on flow, wall-shearing stress and distribution of dissolved material in diseased artery as compared to the normal.

Evaluating the performance of semi-distance-independent competition indices in predicting the basal area growth of individual trees

Recent individual-tree growth models use either distance-dependent or distance-independent competition measures to predict tree increment. However, both measures have deficiencies: the latter because the effects of local variation in spacing are not represented, and the former because they cannot be calculated from normal inventory data for lack of spatial information. To overcome these shortcomings, the new class of semi-distance-independent competition indices was proposed. A semi-distance-independent competition index is a distance-independent competition measure that uses only the trees of a single small sample plot that includes the subject tree. Moreover, a semi-distance-independent competition index can be calculated in an analogous way to a distance-dependent competition index by using sample plot size, tree attributes, and intertree distances. However, many semi-distance-independent competition measures are based on simple tree attributes. Therefore, the objective of this study was to analyze if the semi-distance-independent competition indices explain the variation in measurements of tree increment more or less effectively than a set of classical distance-dependent competition indices. The results show that some of the semi-distance-independent competition indices explain at least as much variation in measurements of tree increment as any of the distance-dependent competition indices.

Effects of Local Variation, Specialty, and Beliefs on Antiviral Prescribing for Influenza

In 2004, we conducted a survey of physician knowledge, attitudes, and practices regarding influenza diagnosis and treatment at Baystate Medical Center in Massachusetts and Scott & White Hospital and Clinic in Texas. Of the 579 physicians we contacted, 336 completed the survey. Sixty-one percent of the respondents prescribed antivirals, and 62% used rapid testing. Prescribing practices were associated with location, practice size, use of rapid testing, and belief in the efficacy of antivirals.

ESTIMATION OF THE FRACTAL DIMENSION OF FRACTURE SURFACE PATTERNS BY BOX-COUNTING METHOD

In the box-counting method, positioning of images do not significantly affect the estimation of the fractal dimension of river pattern on the brittle fracture surface, and that of dimple pattern on the ductile fracture surface of materials. A reasonable estimation of the fractal dimension can be made using the box-counting method by a single measurement on the fracture surface pattern. The fractal dimension of dimple pattern in pure Zn polycrystals (about 1.50) is larger than that of river pattern in soda-lime glass (about 1.30). Personal difference in image processing does not have a large influence on the estimation of the fractal dimension of grain-boundary fracture surface profile, compared with the effects of local variation in fracture pattern concerning image size.

Caterpillar abundance in the territory affects the breeding performance of great tit Parus major minor.

The effects of caterpillar food supply on the breeding performance of a population of the Japanese great tit Parus major minor were investigated. Since more than 90% of the food items in our study site were caterpillars living on trees, we estimated the food availability using 20 frass traps per hectare. The sampling error of this method was about 10% on average, which was accurate enough to detect differences between territories. Food abundance at laying in each territory affected the timing of egg laying. However, food amount after hatching was correlated with clutch size. No relationship was found between fledgling quality and food availability, probably because the effects of local variation in food abundance could be canceled out by parental effort such as extending the foraging area. There was a significant negative correlation between the length of the nestling period and food availability. We suggest that parent tits decide the timing of fledging at the point where two factors, predation risk before fledging and additional improvement of nestling quality, are balanced. Food availability just after fledging affected the length of post-fledging parental care; it seems that fledglings in "poor" territories would have had difficulty in finding food and hence needed to depend on their parents longer than those in "rich" territories.

Subduction-Related Structure Along Eastern Aleutian Trench: ABSTRACT

Along the eastern Aleutian Trench between Kayak and Sanak Islands, the trench, magmatic arc, and active Benioff zone define a modern convergent margin 13,000 km long. The structures developed during the past 10 to 15 m.y. show the deformation associated with subduction. Fore-arc basins have been formed on pre-Neogene rock that was presumably accreted, uplifted, and then locally depressed. Structures in the basins are compressional near the shelf edge and extensional farther toward the arc. The trench lower slope is underlain by rocks that are coeval with those in the fore-arc basin, but are deformed as a result of subduction. Despite a uniform convergence history, the margin has marked structural variations along strike that reflect local non-tectonic influences on struct ral style. The structure could be influenced by a variety of geologic variables such as sediment volumes on the slope, in the trench, and on the ocean crust, and perhaps by the morphology of the igneous ocean crust. Although we have not yet successfully reconciled all the effects of local variation on structural style, a comparative study of these styles and local features can help define kinematic processes associated with plate convergence. End_of_Article - Last_Page 1004------------

Flux pinning by small perturbations in the superconducting order parameter in type-II superconductors

Abstract From a first-order perturbation of the Ginzburg–Landau free energy, the effects of local variation of the upper critical field H c2 and Ginzburg–Landau parameter κ are combined. The interaction energy ∼ |ψ|2[1 – |ψ|2] thus obtained, where |ψ| is the superconducting order parameter, varies locally. The elementary pinning force f p is calculated from the interaction energy as a function of the magnetic induction B, and is seen to be in good agreement with experimental results for several flux-pinning systems.