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Sample records for allometric scaling relationships

  1. An allometric scaling relationship in the brain of preterm infants

    PubMed Central

    Paul, Rachel A; Smyser, Christopher D; Rogers, Cynthia E; English, Ian; Wallendorf, Michael; Alexopoulos, Dimitrios; Meyer, Erin J; Van Essen, David C; Neil, Jeffrey J; Inder, Terrie E

    2014-01-01

    Allometry has been used to demonstrate a power–law scaling relationship in the brain of premature born infants. Forty-nine preterm infants underwent neonatal MRI scans and neurodevelopmental testing at age 2. Measures of cortical surface area and total cerebral volume demonstrated a power–law scaling relationship (α = 1.27). No associations were identified between these measures and investigated clinical variables. Term equivalent cortical surface area and total cerebral volume measures and scaling exponents were not related to outcome. These findings confirm a previously reported allometric scaling relationship in the preterm brain, and suggest that scaling is not a sensitive indicator of aberrant cortical maturation. PMID:25540808

  2. Allometric scaling of countries

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Yu, Tongkui

    2010-11-01

    As huge complex systems consisting of geographic regions, natural resources, people and economic entities, countries follow the allometric scaling law which is ubiquitous in ecological, and urban systems. We systematically investigated the allometric scaling relationships between a large number of macroscopic properties and geographic (area), demographic (population) and economic (GDP, gross domestic production) sizes of countries respectively. We found that most of the economic, trade, energy consumption, communication related properties have significant super-linear (the exponent is larger than 1) or nearly linear allometric scaling relations with the GDP. Meanwhile, the geographic (arable area, natural resources, etc.), demographic (labor force, military age population, etc.) and transportation-related properties (road length, airports) have significant and sub-linear (the exponent is smaller than 1) allometric scaling relations with area. Several differences of power law relations with respect to the population between countries and cities were pointed out. First, population increases sub-linearly with area in countries. Second, the GDP increases linearly in countries but not super-linearly as in cities. Finally, electricity or oil consumption per capita increases with population faster than cities.

  3. Stand variation in Pinus radiata and its relationship with allometric scaling and critical buckling height

    PubMed Central

    Waghorn, Matthew J.; Watt, Michael S.

    2013-01-01

    Background and Aims Allometric relationships and the determination of critical buckling heights have been examined for Pinus radiata in the past. However, how they relate to more mature Pinus radiata exhibiting a wide range of stem diameters, slenderness and modulus of elasticity (E) at operationally used stand densities is largely unknown. The aim of this study was to examine the relationship between Pinus radiata stand structure variables and allometric scaling and critical buckling height. Methods Utilizing a Pinus radiata Nelder trial with stand density and genetic breed as variables, critical buckling height was calculated whilst reduced major axis regression was used to determine scaling exponents between critical height (Hcrit), actual height (H), ground line diameter (D), slenderness (S), density-specific stiffness (E/ρ) and modulus of elasticity (E). Key Results Critical buckling height was highly responsive to decreasing diameter and increasing slenderness. Safety factors in this study were typically considerably lower than previously reported margins in other species. As density-specific stiffness scaled negatively with diameter, the exponent of 0·55 between critical height and diameter did not meet the assumed value of 0·67 under constant density-specific stiffness. E scaled positively with stem slenderness to the power of 0·78. Conclusions The findings suggest that within species density-specific stiffness variation may influence critical height and the scaling exponent between critical height and diameter, which is considered so important in assumptions regarding allometric relationships. PMID:23388878

  4. Allometric scaling relationship between above- and below-ground biomass within and across five woody seedlings

    PubMed Central

    Cheng, Dongliang; Ma, Yuzhu; Zhong, Quanling; Xu, Weifeng

    2014-01-01

    Allometric biomass allocation theory predicts that leaf biomass (ML) scaled isometrically with stem (MS) and root (MR) biomass, and thus above-ground biomass (leaf and stem) (MA) and root (MR) scaled nearly isometrically with below-ground biomass (root) for tree seedlings across a wide diversity of taxa. Furthermore, prior studies also imply that scaling constant should vary with species. However, litter is known about whether such invariant isometric scaling exponents hold for intraspecific biomass allocation, and how variation in scaling constants influences the interspecific scaling relationship between above- and below-ground biomass. Biomass data of seedlings from five evergreen species were examined to test scaling relationships among biomass components across and within species. Model Type II regression was used to compare the numerical values of scaling exponents and constants among leaf, stem, root, and above- to below-ground biomass. The results indicated that ML and MS scaled in an isometric or a nearly isometric manner with MR, as well as MA to MR for five woody species. Significant variation was observed in the Y-intercepts of the biomass scaling curves, resulting in the divergence for intraspecific scaling and interspecific scaling relationships for ML versus MS and ML versus MR, but not for MS versus MR and MA versus MR. We conclude, therefore, that a nearly isometric scaling relationship of MA versus MR holds true within each of the studied woody species and across them irrespective the negative scaling relationship between leaf and stem. PMID:25505524

  5. Allometric scaling relationship between frequency of intestinal contraction and body size in rodents and rabbits.

    PubMed

    Arab, Hossein-Ali; Muhammadnejad, Samad; Naeimi, Saeideh; Arab, Attieh

    2013-06-01

    This study aimed to establish an allometric scaling relationship between the frequency of intestinal contractions and body mass of different mammalian species. The frequency of intestinal contractions of rabbit, guinea pig, rat and mouse were measured using an isolated organ system. The isolated rings were prepared from proximal segments of jejunums and the frequency of contractions was recorded by an isometric force procedure. The coefficients of the obtained allometric equation were ascertained by computation of least squares after logarithmic transformation of both body mass and frequency. Significant differences (p less than 0.001) were shown in the frequency of contractions between different species. The highest frequency that corresponded to the mice was 57.7 min-1 and the 95 percent confidence interval (CI) ranged from 45.4 to 70, while rabbits showed the lowest frequency (12.71 min-1, CI: 8.6-16.8). Logarithms of frequency were statistically proportional to logarithms of body mass (r00.99; p less than 0.001). The data fitted an equation F 1/4 18:51B 0:31 and the 95 percent confidence interval of the exponent ranged from -0.30 to -0.32. The results of this study suggest that it is probably possible to extrapolate the intestinal contraction frequency of other mammalian species by the means of allometry scaling. PMID:23660674

  6. Allometric scaling of intraspecific space use.

    PubMed

    Rosten, Carolyn M; Gozlan, Rodolphe E; Lucas, Martyn C

    2016-03-01

    Allometric scaling relationships enable exploration of animal space-use patterns, yet interspecific studies cannot address many of the underlying mechanisms. We present the first intraspecific study of home range (HR) allometry relative to energetic requirements over several orders of magnitude of body mass, using as a model the predatory fish, pike Esox lucius. Analogous with interspecific studies, we show that space use increases more rapidly with mass (exponent = 1.08) than metabolic scaling theories predict. Our results support a theory that suggests increasing HR overlap with body mass explains many of these differences in allometric scaling of HR size. We conclude that, on a population scale, HR size and energetic requirement scale allometrically, but with different exponents. PMID:26979558

  7. Allometric scaling of intraspecific space use

    PubMed Central

    Gozlan, Rodolphe E.

    2016-01-01

    Allometric scaling relationships enable exploration of animal space-use patterns, yet interspecific studies cannot address many of the underlying mechanisms. We present the first intraspecific study of home range (HR) allometry relative to energetic requirements over several orders of magnitude of body mass, using as a model the predatory fish, pike Esox lucius. Analogous with interspecific studies, we show that space use increases more rapidly with mass (exponent = 1.08) than metabolic scaling theories predict. Our results support a theory that suggests increasing HR overlap with body mass explains many of these differences in allometric scaling of HR size. We conclude that, on a population scale, HR size and energetic requirement scale allometrically, but with different exponents. PMID:26979558

  8. Allometric Scaling in Biology

    NASA Astrophysics Data System (ADS)

    Banavar, Jayanth

    2009-03-01

    The unity of life is expressed not only in the universal basis of inheritance and energetics at the molecular level, but also in the pervasive scaling of traits with body size at the whole-organism level. More than 75 years ago, Kleiber and Brody and Proctor independently showed that the metabolic rates, B, of mammals and birds scale as the three-quarter power of their mass, M. Subsequent studies showed that most biological rates and times scale as M-1/4 and M^1/4 respectively, and that these so called quarter-power scaling relations hold for a variety of organisms, from unicellular prokaryotes and eukaryotes to trees and mammals. The wide applicability of Kleiber's law, across the 22 orders of magnitude of body mass from minute bacteria to giant whales and sequoias, raises the hope that there is some simple general explanation that underlies the incredible diversity of form and function. We will present a general theoretical framework for understanding the relationship between metabolic rate, B, and body mass, M. We show how the pervasive quarter-power biological scaling relations arise naturally from optimal directed resource supply systems. This framework robustly predicts that: 1) whole organism power and resource supply rate, B, scale as M^3/4; 2) most other rates, such as heart rate and maximal population growth rate scale as M-1/4; 3) most biological times, such as blood circulation time and lifespan, scale as M^1/4; and 4) the average velocity of flow through the network, v, such as the speed of blood and oxygen delivery, scales as M^1/12. Our framework is valid even when there is no underlying network. Our theory is applicable to unicellular organisms as well as to large animals and plants. This work was carried out in collaboration with Amos Maritan along with Jim Brown, John Damuth, Melanie Moses, Andrea Rinaldo, and Geoff West.

  9. The Leaf Size–Twig Size Spectrum of Temperate Woody Species Along an Altitudinal Gradient: An Invariant Allometric Scaling Relationship

    PubMed Central

    SUN, SHUCUN; JIN, DONGMEI; SHI, PEILI

    2006-01-01

    • Background and Aims The leaf size–twig size spectrum is one of the leading dimensions of plant ecological variation, and now it is under development. The purpose of this study was to test whether the relationship between leaf size and twig size is isometric or allometric, and to examine the relationship between plant allometric growth and life history strategies in the spectrum. • Methods Leaf and stem characters—including leaf and stem mass, total leaf area, individual leaf area, stem cross-sectional area, leaf number and stem length—at the twig level for 59 woody species were investigated along an altitudinal gradient on Changbaishan Mountain in the temperate zone of China. The environmental gradient ranges from temperate broad-leaved mixed forest at low altitude, to conifer forest at middle altitude, and to sub-alpine birch forest at high altitude. The scaling relationships between stem cross-sectional area and stem mass, stem mass and leaf mass, and leaf mass and leaf area at the twig level were simultaneously determined. • Key Results Twig cross-sectional area was found to have invariant allometric scaling relationships with the stem mass, leaf mass, total leaf area and individual leaf area, all with common slopes being significantly larger than 1, for three altitudinal-zoned vegetation types under investigation. However, leaf mass was found to be isometrically related to stem mass and leaf area along the environmental gradient. Based on the predictions of previous models, the exponent value of the relationship between twig cross-sectional area and total leaf area can be inferred to be 1·5, which falls between the confidence intervals of the relationship at each altitude, and between the confidence intervals of the common slope value (1·17–1·56) of this study. This invariant scaling relationship is assumed to result from the fractural network and/or developmental constraints of plants. The allometric constants (y-intercepts) of the

  10. Allometric scaling laws of metabolism

    NASA Astrophysics Data System (ADS)

    da Silva, Jafferson Kamphorst Leal; Garcia, Guilherme J. M.; Barbosa, Lauro A.

    2006-12-01

    One of the most pervasive laws in biology is the allometric scaling, whereby a biological variable Y is related to the mass M of the organism by a power law, Y=YM, where b is the so-called allometric exponent. The origin of these power laws is still a matter of dispute mainly because biological laws, in general, do not follow from physical ones in a simple manner. In this work, we review the interspecific allometry of metabolic rates, where recent progress in the understanding of the interplay between geometrical, physical and biological constraints has been achieved. For many years, it was a universal belief that the basal metabolic rate (BMR) of all organisms is described by Kleiber's law (allometric exponent b=3/4). A few years ago, a theoretical basis for this law was proposed, based on a resource distribution network common to all organisms. Nevertheless, the 3/4-law has been questioned recently. First, there is an ongoing debate as to whether the empirical value of b is 3/4 or 2/3, or even nonuniversal. Second, some mathematical and conceptual errors were found these network models, weakening the proposed theoretical arguments. Another pertinent observation is that the maximal aerobically sustained metabolic rate of endotherms scales with an exponent larger than that of BMR. Here we present a critical discussion of the theoretical models proposed to explain the scaling of metabolic rates, and compare the predicted exponents with a review of the experimental literature. Our main conclusion is that although there is not a universal exponent, it should be possible to develop a unified theory for the common origin of the allometric scaling laws of metabolism.

  11. Allometric scaling relationships of jumping performance in the striped marsh frog Limnodynastes peronii.

    PubMed

    Wilson, R S; Franklin, C E; James, R S

    2000-06-01

    We constructed a force platform to investigate the scaling relationships of the detailed dynamics of jumping performance in striped marsh frogs (Limnodynastes peronii). Data were used to test between two alternative models that describe the scaling of anuran jumping performance; Hill's model, which predicts mass- independence of jump distance, and Marsh's model, which predicts that jump distance increases as M(0.2), where M is body mass. From the force platform, scaling relationships were calculated for maximum jumping force (F(max)), acceleration, take-off velocity (U(max)), mass-specific jumping power (P(max)), total jumping distance (D(J)) and total contact time for 75 L. peronii weighing between 2.9 and 38. 4 g. F(max) was positively correlated with body mass and was described by the equation F(max)=0.16M(0.61), while P(max) decreased significantly with body mass and was described by the equation P(max)=347M(-)(0.46). Both D(J) and U(max) were mass-independent over the post-metamorph size range, and thus more closely resembled Hill's model for the scaling of locomotion. We also examined the scaling relationships of jumping performance in metamorph L. peronii by recording the maximum jump distance of 39 animals weighing between 0.19 and 0.58 g. In contrast to the post-metamorphic L. peronii, D(J) and U(max) were highly dependent on body mass in metamorphs and were described by the equations D(J)=38M(0.53) and U(max)=1.82M(0.23), respectively. Neither model for the scaling of anuran jumping performance resembled data from metamorph L. peronii. Although the hindlimbs of post-metamorphic L. peronii scaled geometrically (body mass exponent approximately 0.33), the hindlimbs of metamorphs showed greater proportional increases with body mass (mass exponents of 0.41-0.42). PMID:10821750

  12. Allometric Scaling Across Environmental Gradients

    NASA Astrophysics Data System (ADS)

    Duncanson, L.; Dubayah, R.

    2014-12-01

    Developing a better understanding of the controls on biomass allocation in forested systems and the consequences for carbon stocks and fluxes is required for improved ecosystem and climate modeling. A simple model, based largely on resource distribution networks, was presented by West, Brown and Enquist (1999). Their model predicts that the exponents of allometric relationships between many forest structural and functional properties will be constants, irrespective of environment or species. In this research we assess the validity of model predictions across the United States and examine their independence with respect to environment. We focus on two relationships with particular importance to biomass: Ht ∝ DBH2/3 nDBH ∝ DBH-2 where Ht is height, DBH is Diameter at Breast Height, and nDBH is the number of trees in a given DBH size class. We obtained DBH and height data from the U.S. Forest Inventory Analysis (FIA) dataset, and fit an exponent to each relationship for every FIA plot across the US. We extracted environmental data from the FIA plots (forest maximum height, species type, age, topography) and the North American Regional Reassessment dataset (precipitation, temperature, PAR) and performed random forest regression to estimate observed exponents as a function of environment. We found that forest height, age, and forest type were the most important drivers of allometry, explaining about 40% of observed variability. We found that for both relationships, as forest height and age increase, exponents constrain to the theoretical predictions presented by WBE. This suggests that WBE predictions are valid and may be useful constraints in biomass mapping and ecosystem flux models. However, they deviate from predictions in younger, shorter stands where forests have not had time to develop a complex size structure. Additionally, there is a significant difference in both relationships between conifer and deciduous-dominated stands, suggesting that species type

  13. Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

    PubMed

    Bastille-Rousseau, Guillaume; Yackulic, Charles B; Frair, Jacqueline L; Cabrera, Freddy; Blake, Stephen

    2016-09-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  14. Allometric and temporal scaling of movement characteristics in Galapagos tortoises

    USGS Publications Warehouse

    Bastille-Rousseau, Guillaume; Yackulic, Charles B.; Frair, Jacqueline L.; Cabrera, Freddy; Blake, Stephen

    2016-01-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs.We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour – giant Galapagos tortoises (Chelonoidis spp.) – to test how movement metrics estimated on a monthly basis scaled with body size.We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex.Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates.Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  15. Allometric Scaling of Wingate Anaerobic Power Test Scores in Women

    ERIC Educational Resources Information Center

    Hetzler, Ronald K.; Stickley, Christopher D.; Kimura, Iris F.

    2011-01-01

    In this study, we developed allometric exponents for scaling Wingate anaerobic test (WAnT) power data that are reflective in controlling for body mass (BM) and lean body mass (LBM) and established a normative WAnT data set for college-age women. One hundred women completed a standard WAnT. Allometric exponents and percentile ranks for peak (PP)…

  16. Problems of allometric scaling analysis: examples from mammalian reproductive biology.

    PubMed

    Martin, Robert D; Genoud, Michel; Hemelrijk, Charlotte K

    2005-05-01

    Biological scaling analyses employing the widely used bivariate allometric model are beset by at least four interacting problems: (1) choice of an appropriate best-fit line with due attention to the influence of outliers; (2) objective recognition of divergent subsets in the data (allometric grades); (3) potential restrictions on statistical independence resulting from phylogenetic inertia; and (4) the need for extreme caution in inferring causation from correlation. A new non-parametric line-fitting technique has been developed that eliminates requirements for normality of distribution, greatly reduces the influence of outliers and permits objective recognition of grade shifts in substantial datasets. This technique is applied in scaling analyses of mammalian gestation periods and of neonatal body mass in primates. These analyses feed into a re-examination, conducted with partial correlation analysis, of the maternal energy hypothesis relating to mammalian brain evolution, which suggests links between body size and brain size in neonates and adults, gestation period and basal metabolic rate. Much has been made of the potential problem of phylogenetic inertia as a confounding factor in scaling analyses. However, this problem may be less severe than suspected earlier because nested analyses of variance conducted on residual variation (rather than on raw values) reveals that there is considerable variance at low taxonomic levels. In fact, limited divergence in body size between closely related species is one of the prime examples of phylogenetic inertia. One common approach to eliminating perceived problems of phylogenetic inertia in allometric analyses has been calculation of 'independent contrast values'. It is demonstrated that the reasoning behind this approach is flawed in several ways. Calculation of contrast values for closely related species of similar body size is, in fact, highly questionable, particularly when there are major deviations from the best

  17. Quantum statistics and allometric scaling of organisms

    NASA Astrophysics Data System (ADS)

    Demetrius, Lloyd

    2003-05-01

    This article proposes a mechanism to explain allometric relations between basal metabolic rate and the body size of organisms. The model postulates that energy transduction in biological organisms is constrained by two classes of dynamical processes: The first process has its origin in quantum mechanics and the constraints which the coupling of electron transport and proton translocation impose on metabolic activity. The second derives from evolutionary dynamics and the constraints which ecological and demographic forces impose on metabolic rate. These two processes are invoked to show that the scaling exponent between basal metabolic rate and body size follows a {3}/{4} rule, in the case of organisms subject to ecological constraints defined by scarce but dependable resources, and a {2}/{3} rule when constraints are defined by ample but only temporarily available resources. Our conclusions are based on general arguments incorporating the molecular mechanisms that determine metabolic activity at all levels of biological organization. Hence the model applies to uni-cellular organisms, plants and animals.

  18. Interspecies Allometric Scaling of Antimalarial Drugs and Potential Application to Pediatric Dosing

    PubMed Central

    Senarathna, S. M. D. K. Ganga

    2014-01-01

    Pharmacopeial recommendations for administration of antimalarial drugs are the same weight-based (mg/kg of body weight) doses for children and adults. However, linear calculations are known to underestimate pediatric doses; therefore, interspecies allometric scaling data may have a role in predicting doses in children. We investigated the allometric scaling relationships of antimalarial drugs using data from pharmacokinetic studies in mammalian species. Simple allometry (Y = a × Wb) was utilized and compared to maximum life span potential (MLP) correction. All drugs showed a strong correlation with clearance (CL) in healthy controls. Insufficient data from malaria-infected species other than humans were available for allometric scaling. The allometric exponents (b) for CL of artesunate, dihydroartemisinin (from intravenous artesunate), artemether, artemisinin, clindamycin, piperaquine, mefloquine, and quinine were 0.71, 0.85, 0.66, 0.83, 0.62, 0.96, 0.52, and 0.40, respectively. Clearance was significantly lower in malaria infection than in healthy (adult) humans for quinine (0.07 versus 0.17 liter/h/kg; P = 0.0002) and dihydroartemisinin (0.81 versus 1.11 liters/h/kg; P = 0.04; power = 0.6). Interpolation of simple allometry provided better estimates of CL for children than MLP correction, which generally underestimated CL values. Pediatric dose calculations based on simple allometric exponents were 10 to 70% higher than pharmacopeial (mg/kg) recommendations. Interpolation of interspecies allometric scaling could provide better estimates than linear scaling of adult to pediatric doses of antimalarial drugs; however, the use of a fixed exponent for CL was not supported in the present study. The variability in allometric exponents for antimalarial drugs also has implications for scaling of fixed-dose combinations. PMID:25092696

  19. Relations between allometric scalings and fluctuations in complex systems: The case of Japanese firms

    NASA Astrophysics Data System (ADS)

    Watanabe, Hayafumi; Takayasu, Hideki; Takayasu, Misako

    2013-02-01

    To elucidate allometric scaling in complex systems, we investigated the underlying scaling relationships between typical three-scale indicators for approximately 500,000 Japanese firms; namely, annual sales, number of employees, and number of business partners. First, new scaling relations including the distributions of fluctuations were discovered by systematically analyzing conditional statistics. Second, we introduced simple probabilistic models that reproduce all these scaling relations, and we derived relations between scaling exponents and the magnitude of fluctuations.

  20. Allometric scaling and accidents at work

    PubMed Central

    Cempel, Czesław; Tabaszewski, Maciej; Ordysiński, Szymon

    2016-01-01

    Allometry is the knowledge concerning relations between the features of some beings, like animals, or cities. For example, the daily energy rate is proportional to a mass of mammals rise of 3/4. This way of thinking has spread quickly from biology to many areas of research concerned with sociotechnical systems. It was revealed that the number of innovations, patents or heavy crimes rises as social interaction increases in a bigger city, while other urban indexes such as suicides decrease with social interaction. Enterprise is also a sociotechnical system, where social interaction and accidents at work take place. Therefore, do these interactions increase the number of accidents at work or, on the contrary, are they reduction-driving components? This article tries to catch such links and assess the allometric exponent between the number of accidents at work and the number of employees in an enterprise. PMID:26655044

  1. Allometric scaling and accidents at work.

    PubMed

    Cempel, Czesław; Tabaszewski, Maciej; Ordysiński, Szymon

    2016-01-01

    Allometry is the knowledge concerning relations between the features of some beings, like animals, or cities. For example, the daily energy rate is proportional to a mass of mammals rise of 3/4. This way of thinking has spread quickly from biology to many areas of research concerned with sociotechnical systems. It was revealed that the number of innovations, patents or heavy crimes rises as social interaction increases in a bigger city, while other urban indexes such as suicides decrease with social interaction. Enterprise is also a sociotechnical system, where social interaction and accidents at work take place. Therefore, do these interactions increase the number of accidents at work or, on the contrary, are they reduction-driving components? This article tries to catch such links and assess the allometric exponent between the number of accidents at work and the number of employees in an enterprise. PMID:26655044

  2. Allometric scaling for predicting human clearance of bisphenol A

    SciTech Connect

    Collet, Séverine H. Picard-Hagen, Nicole Lacroix, Marlène Z. Puel, Sylvie Viguié, Catherine Bousquet-Melou, Alain Toutain, Pierre-Louis Gayrard, Véronique

    2015-05-01

    The investigation of interspecies differences in bisphenol A (BPA) pharmacokinetics (PK) may be useful for translating findings from animal studies to humans, identifying major processes involved in BPA clearance mechanisms, and predicting BPA PK parameters in man. For the first time, a large range of species in terms of body weight, from 0.02 kg (mice) to 495 kg (horses) was used to predict BPA clearance in man by an allometric approach. BPA PK was evaluated after intravenous administration of BPA in horses, sheep, pigs, dogs, rats and mice. A non-compartmental analysis was used to estimate plasma clearance and steady state volume of distribution and predict BPA PK parameters in humans from allometric scaling. In all the species investigated, BPA plasma clearance was high and of the same order of magnitude as their respective hepatic blood flow. By an allometric scaling, the human clearance was estimated to be 1.79 L/min (equivalent to 25.6 mL/kg.min) with a 95% prediction interval of 0.36 to 8.83 L/min. Our results support the hypothesis that there are highly efficient and hepatic mechanisms of BPA clearance in man. - Highlights: • Allometric scaling was used to predict BPA pharmacokinetic parameters in humans. • In all species, BPA plasma clearance approached hepatic blood flow. • Human BPA clearance was estimated to be 1.79 L/min.

  3. Thermodynamics Constrains Allometric Scaling of Optimal Development Time in Insects

    PubMed Central

    Dillon, Michael E.; Frazier, Melanie R.

    2013-01-01

    Development time is a critical life-history trait that has profound effects on organism fitness and on population growth rates. For ectotherms, development time is strongly influenced by temperature and is predicted to scale with body mass to the quarter power based on 1) the ontogenetic growth model of the metabolic theory of ecology which describes a bioenergetic balance between tissue maintenance and growth given the scaling relationship between metabolism and body size, and 2) numerous studies, primarily of vertebrate endotherms, that largely support this prediction. However, few studies have investigated the allometry of development time among invertebrates, including insects. Abundant data on development of diverse insects provides an ideal opportunity to better understand the scaling of development time in this ecologically and economically important group. Insects develop more quickly at warmer temperatures until reaching a minimum development time at some optimal temperature, after which development slows. We evaluated the allometry of insect development time by compiling estimates of minimum development time and optimal developmental temperature for 361 insect species from 16 orders with body mass varying over nearly 6 orders of magnitude. Allometric scaling exponents varied with the statistical approach: standardized major axis regression supported the predicted quarter-power scaling relationship, but ordinary and phylogenetic generalized least squares did not. Regardless of the statistical approach, body size alone explained less than 28% of the variation in development time. Models that also included optimal temperature explained over 50% of the variation in development time. Warm-adapted insects developed more quickly, regardless of body size, supporting the “hotter is better” hypothesis that posits that ectotherms have a limited ability to evolutionarily compensate for the depressing effects of low temperatures on rates of biological processes

  4. Allometric scaling for predicting human clearance of bisphenol A.

    PubMed

    Collet, Séverine H; Picard-Hagen, Nicole; Lacroix, Marlène Z; Puel, Sylvie; Viguié, Catherine; Bousquet-Melou, Alain; Toutain, Pierre-Louis; Gayrard, Véronique

    2015-05-01

    The investigation of interspecies differences in bisphenol A (BPA) pharmacokinetics (PK) may be useful for translating findings from animal studies to humans, identifying major processes involved in BPA clearance mechanisms, and predicting BPA PK parameters in man. For the first time, a large range of species in terms of body weight, from 0.02 kg (mice) to 495 kg (horses) was used to predict BPA clearance in man by an allometric approach. BPA PK was evaluated after intravenous administration of BPA in horses, sheep, pigs, dogs, rats and mice. A non-compartmental analysis was used to estimate plasma clearance and steady state volume of distribution and predict BPA PK parameters in humans from allometric scaling. In all the species investigated, BPA plasma clearance was high and of the same order of magnitude as their respective hepatic blood flow. By an allometric scaling, the human clearance was estimated to be 1.79 L/min (equivalent to 25.6 mL/kg.min) with a 95% prediction interval of 0.36 to 8.83 L/min. Our results support the hypothesis that there are highly efficient and hepatic mechanisms of BPA clearance in man. PMID:25759244

  5. Allometric scaling of marbofloxacin pharmacokinetics: a retrospective analysis.

    PubMed

    Yohannes, S; Hossain, Md Akil; Kim, J Y; Lee, S J; Kwak, D M; Suh, J W; Park, S C

    2014-01-01

    The association between physiologically dependent pharmacokinetic parameters (CL(B), T1/2beta, Vd(ss)) of marbofloxacin and body weight was studied in eight animal species based on allometric equation Y = aWb, where 'Y' is the pharmacokinetic parameter, 'W' is body weight, 'a' is allometric coefficient (intercept) and 'b' is the exponent that describes relation between pharmacokinetic parameter and body weight. The body clearance of marbofloxacin has shown significant (P < 0.0001) relation with size (Bwt) in various animal species. However, half-life and volume of distribution were not in association with body weight. Although half-life and volume of distribution were not in a good correlation with body weight, statistically significant association between the body clearance and body weight suggests validity of allometric scaling for predicting pharmacokinetic parameters of marbofloxacin in animal species that have not been studied yet. However further study considering large sample size and other parameters influencing pharmacokinetics of marbofloxacin is recommended. PMID:24724476

  6. Allometric Convergence in Savanna Trees and Implications for the Use of Plant Scaling Models in Variable Ecosystems

    PubMed Central

    Tredennick, Andrew T.; Bentley, Lisa Patrick; Hanan, Niall P.

    2013-01-01

    Theoretical models of allometric scaling provide frameworks for understanding and predicting how and why the morphology and function of organisms vary with scale. It remains unclear, however, if the predictions of ‘universal’ scaling models for vascular plants hold across diverse species in variable environments. Phenomena such as competition and disturbance may drive allometric scaling relationships away from theoretical predictions based on an optimized tree. Here, we use a hierarchical Bayesian approach to calculate tree-specific, species-specific, and ‘global’ (i.e. interspecific) scaling exponents for several allometric relationships using tree- and branch-level data harvested from three savanna sites across a rainfall gradient in Mali, West Africa. We use these exponents to provide a rigorous test of three plant scaling models (Metabolic Scaling Theory (MST), Geometric Similarity, and Stress Similarity) in savanna systems. For the allometric relationships we evaluated (diameter vs. length, aboveground mass, stem mass, and leaf mass) the empirically calculated exponents broadly overlapped among species from diverse environments, except for the scaling exponents for length, which increased with tree cover and density. When we compare empirical scaling exponents to the theoretical predictions from the three models we find MST predictions are most consistent with our observed allometries. In those situations where observations are inconsistent with MST we find that departure from theory corresponds with expected tradeoffs related to disturbance and competitive interactions. We hypothesize savanna trees have greater length-scaling exponents than predicted by MST due to an evolutionary tradeoff between fire escape and optimization of mechanical stability and internal resource transport. Future research on the drivers of systematic allometric variation could reconcile the differences between observed scaling relationships in variable ecosystems and those

  7. Metabolic allometric scaling model: combining cellular transportation and heat dissipation constraints.

    PubMed

    Shestopaloff, Yuri K

    2016-08-15

    Living organisms need energy to be 'alive'. Energy is produced by the biochemical processing of nutrients, and the rate of energy production is called the metabolic rate. Metabolism is very important from evolutionary and ecological perspectives, and for organismal development and functioning. It depends on different parameters, of which organism mass is considered to be one of the most important. Simple relationships between the mass of organisms and their metabolic rates were empirically discovered by M. Kleiber in 1932. Such dependence is described by a power function, whose exponent is referred to as the allometric scaling coefficient. With the increase of mass, the metabolic rate usually increases more slowly; if mass increases by two times, the metabolic rate increases less than two times. This fact has far-reaching implications for the organization of life. The fundamental biological and biophysical mechanisms underlying this phenomenon are still not well understood. The present study shows that one such primary mechanism relates to transportation of substances, such as nutrients and waste, at a cellular level. Variations in cell size and associated cellular transportation costs explain the known variance of the allometric exponent. The introduced model also includes heat dissipation constraints. The model agrees with experimental observations and reconciles experimental results across different taxa. It ties metabolic scaling to organismal and environmental characteristics, helps to define perspective directions of future research and allows the prediction of allometric exponents based on characteristics of organisms and the environments they live in. PMID:27284070

  8. Modeling aboveground tree woody biomass using national-scale allometric methods and airborne lidar

    NASA Astrophysics Data System (ADS)

    Chen, Qi

    2015-08-01

    Estimating tree aboveground biomass (AGB) and carbon (C) stocks using remote sensing is a critical component for understanding the global C cycle and mitigating climate change. However, the importance of allometry for remote sensing of AGB has not been recognized until recently. The overarching goals of this study are to understand the differences and relationships among three national-scale allometric methods (CRM, Jenkins, and the regional models) of the Forest Inventory and Analysis (FIA) program in the U.S. and to examine the impacts of using alternative allometry on the fitting statistics of remote sensing-based woody AGB models. Airborne lidar data from three study sites in the Pacific Northwest, USA were used to predict woody AGB estimated from the different allometric methods. It was found that the CRM and Jenkins estimates of woody AGB are related via the CRM adjustment factor. In terms of lidar-biomass modeling, CRM had the smallest model errors, while the Jenkins method had the largest ones and the regional method was between. The best model fitting from CRM is attributed to its inclusion of tree height in calculating merchantable stem volume and the strong dependence of non-merchantable stem biomass on merchantable stem biomass. This study also argues that it is important to characterize the allometric model errors for gaining a complete understanding of the remotely-sensed AGB prediction errors.

  9. FAST TRACK COMMUNICATION: Unified theory of interspecific allometric scaling

    NASA Astrophysics Data System (ADS)

    da Silva, Jafferson K. L.; Barbosa, Lauro A.; Silva, Paulo Roberto

    2007-11-01

    A general simple theory for the interspecific allometric scaling is developed in the d + 1-dimensional space (d biological lengths and a physiological time) of metabolic states of organisms. It is assumed that natural selection shaped the metabolic states in such a way that the mass and energy d + 1-densities are size-invariant quantities (independent of body mass). The different metabolic states (basal and maximum) are described by considering that the biological lengths and the physiological time are related by different transport processes of energy and mass. In the basal metabolism, transportation occurs by ballistic and diffusion processes. In d = 3, the 3/4 law occurs if the ballistic movement is the dominant process, while the 2/3 law appears when both transport processes are equivalent. Accelerated movement during the biological time is related to the maximum aerobic sustained metabolism, which is characterized by the scaling exponent 2d/(2d + 1) (6/7 in d = 3). The results are in good agreement with empirical data and a verifiable empirical prediction about the aorta blood velocity in maximum metabolic rate conditions is made.

  10. Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants

    PubMed Central

    Bruce, Andrew I.; Burd, Martin

    2012-01-01

    Leaf-cutting ants (Atta spp.) create physical pathways to support the transport of resources on which colony growth and reproduction depend. We determined the scaling relationship between the rate of resource acquisition and the size of the trail system and foraging workforce for 18 colonies of Atta colombica and Atta cephalotes. We examined conventional power-law scaling patterns, but did so in a multivariate analysis that reveals the simultaneous effects of forager number, trail length and trail width. Foraging rate (number of resource-laden ants returning to the nest per unit time) scaled at the 0.93 power of worker numbers, the –1.02 power of total trail length and the 0.65 power of trail width. These scaling exponents indicate that individual performance declines only slightly as more foragers are recruited to the workforce, but that trail length imposes a severe penalty on the foraging rate. A model of mass traffic flow predicts the allometric patterns for workforce and trail length, although the effect of trail width is unexpected and points to the importance of the little-known mechanisms that regulate a colony's investment in trail clearance. These results provide a point of comparison for the role that resource flows may play in allometric scaling patterns in other transport-dependent entities, such as human cities. PMID:22337696

  11. Allometric scaling of infraorbital surface topography in Homo.

    PubMed

    Maddux, Scott D; Franciscus, Robert G

    2009-02-01

    Infraorbital morphology is often included in phylogenetic and functional analyses of Homo. The inclusion of distinct infraorbital configurations, such as the "canine fossa" in Homo sapiens or the "inflated" maxilla in Neandertals, is generally based on either descriptive or qualitative assessments of this morphology, or simple linear chord and subtense measurements. However, the complex curvilinear surface of the infraorbital region has proven difficult to quantify through these traditional methods. In this study, we assess infraorbital shape and its potential allometric scaling in fossil Homo (n=18) and recent humans (n=110) with a geometric morphometric method well-suited for quantifying complex surface topographies. Our results indicate that important aspects of infraorbital shape are correlated with overall infraorbital size across Homo. Specifically, individuals with larger infraorbital areas tend to exhibit relatively flatter infraorbital surface topographies, taller and narrower infraorbital areas, sloped inferior orbital rims, anteroinferiorly oriented maxillary body facies, posteroinferiorly oriented maxillary processes of the zygomatic, and non-everted lateral nasal margins. In contrast, individuals with smaller infraorbital regions generally exhibit relatively depressed surface topographies, shorter and wider infraorbital areas, projecting inferior orbital rims, posteroinferiorly oriented maxillary body facies, anteroinferiorly oriented maxillary processes, and everted lateral nasal margins. These contrasts form a continuum and only appear dichotomized at the ends of the infraorbital size spectrum. In light of these results, we question the utility of incorporating traditionally polarized infraorbital morphologies in phylogenetic and functional analyses without due consideration of continuous infraorbital and facial size variation in Homo. We conclude that the essentially flat infraorbital surface topography of Neandertals is not unique and can be

  12. Interspecies allometric scaling: prediction of clearance in large animal species: part II: mathematical considerations.

    PubMed

    Martinez, M; Mahmood, I; Hunter, R P

    2006-10-01

    Interspecies scaling is a useful tool for the prediction of pharmacokinetic parameters from animals to humans, and it is often used for estimating a first-time in human dose. However, it is important to appreciate the mathematical underpinnings of this scaling procedure when using it to predict pharmacokinetic parameter values across animal species. When cautiously applied, allometry can be a tool for estimating clearance in veterinary species for the purpose of dosage selection. It is particularly valuable during the selection of dosages in large zoo animal species, such as elephants, large cats and camels, for which pharmacokinetic data are scant. In Part I, allometric predictions of clearance in large animal species were found to pose substantially greater risks of inaccuracies when compared with that observed for humans. In this report, we examine the factors influencing the accuracy of our clearance estimates from the perspective of the relationship between prediction error and such variables as the distribution of body weight values used in the regression analysis, the influence of a particular observation on the clearance estimate, and the 'goodness of fit' (R(2)) of the regression line. Ultimately, these considerations are used to generate recommendations regarding the data to be included in the allometric prediction of clearance in large animal species. PMID:16958788

  13. Invariant allometric scaling of nitrogen and phosphorus in leaves, stems, and fine roots of woody plants along an altitudinal gradient.

    PubMed

    Zhao, Ning; Yu, Guirui; He, Nianpeng; Xia, Fucai; Wang, Qiufeng; Wang, Ruili; Xu, Zhiwei; Jia, Yanlong

    2016-07-01

    Nitrogen (N) to phosphorus (P) allocation in plant organs is of particular interest, as both elements are important to regulate plant growth. We analyzed the scaling relationship of N and P in leaves, stems and fine roots of 224 plant species along an altitudinal transect (500-2,300 m) on the northern slope of Changbai Mountain, China. We tested whether the scaling relationships of N and P were conserved in response to environmental variations. We found that the N and P concentrations of the leaves, stems and fine roots decreased, whereas the N:P ratios increased with increasing altitude. Allometric scaling relationships of N and P were found in the leaves, stems and fine roots, with allometric exponents of 0.78, 0.71 and 0.87, respectively. An invariant allometric scaling of N and P in the leaves, stems and fine roots was detected for woody plants along the altitudinal gradient. These results may advance our understanding of plant responses to climate change, and provide a basis for practical implication of various ecological models. PMID:26943163

  14. High-Throughput Tissue Bioenergetics Analysis Reveals Identical Metabolic Allometric Scaling for Teleost Hearts and Whole Organisms

    PubMed Central

    Jayasundara, Nishad; Kozal, Jordan S.; Arnold, Mariah C.; Chan, Sherine S. L.; Di Giulio, Richard T.

    2015-01-01

    Organismal metabolic rate, a fundamental metric in biology, demonstrates an allometric scaling relationship with body size. Fractal-like vascular distribution networks of biological systems are proposed to underlie metabolic rate allometric scaling laws from individual organisms to cells, mitochondria, and enzymes. Tissue-specific metabolic scaling is notably absent from this paradigm. In the current study, metabolic scaling relationships of hearts and brains with body size were examined by improving on a high-throughput whole-organ oxygen consumption rate (OCR) analysis method in five biomedically and environmentally relevant teleost model species. Tissue-specific metabolic scaling was compared with organismal routine metabolism (RMO2), which was measured using whole organismal respirometry. Basal heart OCR and organismal RMO2 scaled identically with body mass in a species-specific fashion across all five species tested. However, organismal maximum metabolic rates (MMO2) and pharmacologically-induced maximum cardiac metabolic rates in zebrafish Danio rerio did not show a similar relationship with body mass. Brain metabolic rates did not scale with body size. The identical allometric scaling of heart and organismal metabolic rates with body size suggests that hearts, the power generator of an organism’s vascular distribution network, might be crucial in determining teleost metabolic rate scaling under routine conditions. Furthermore, these findings indicate the possibility of measuring heart OCR utilizing the high-throughput approach presented here as a proxy for organismal metabolic rate—a useful metric in characterizing organismal fitness. In addition to heart and brain OCR, the current approach was also used to measure whole liver OCR, partition cardiac mitochondrial bioenergetic parameters using pharmacological agents, and estimate heart and brain glycolytic rates. This high-throughput whole-organ bioenergetic analysis method has important applications in

  15. Allometric scaling of indirect effects: body size ratios predict non-consumptive effects in multi-predator systems.

    PubMed

    Krenek, Lauren; Rudolf, Volker H W

    2014-11-01

    Non-consumptive effects (NCES) frequently lead to non-independent effects of multiple predators. While such emergent predator effects are ubiquitous in natural communities, the strength of these effects varies among studies and systems, making it difficult to predict a priory how changes in predator diversity influence prey suppression. Thus, identifying general scaling rules which can explain this variation of non-independent effects is vital for modelling natural communities and how they respond to biodiversity loss. Body size is a key trait determining the nature and strength of ecological interactions. While great progress has been made using allometric relationships to predict the interaction strength of predator-prey pairs, it is unknown whether similar relationships explain variation in the strength of NCEs, and how they are related to consumptive effects. Here, we experimentally manipulate the relative size difference of multiple predators to determine whether NCEs follow general allometric scaling relationships in an aquatic multi-predator system. Results demonstrate that the presence and strength of NCEs can vary dramatically across predator combinations. However, this variation scaled predictably with the size ratio of predators, increasing the size difference among predators increased NCEs. This pattern was driven by a size-mediated shift in 'food web motif' from competition to intraguild predation and a positive correlation of NCEs and intraguild predation rate. Results indicate that models which assume that consumers have independent effects are particularly likely to make erroneous predictions when predators differ substantially in size, but simple allometric relationships of NCEs could be used to correct this bias. PMID:24910170

  16. Allometric scaling for chemical restraint in greater Rheas (Rhea americana) with Tiletamine and Zolazepam

    PubMed Central

    2014-01-01

    Background Chemical restraint is of great importance in the clinical practice of wildlife animals. In such, interspecific allometric scaling proposes pharmacological doses to a wide range of species, based on previously known doses for domestic animals and the target animal’s body mass. The objective was to compare chemical restraint responses in the greater rhea (Rhea americana) with conventional doses of tiletamine/zolazepam, found in the literature for the species, and with doses calculated through interspecific allometric scaling extrapolation. From the Federal University of Piauí, six adult greater rheas (Rhea americana), three males and three females, were randomly selected to be subjects in this research. All six animals were submitted to two chemical restraint protocols with tiletamine and zolazepam, per intramuscular injection in the hind limb. The first protocol was composed of doses found on the literature for the species, while the second protocol used doses calculated by interspecific allometric scaling, with the domestic dog as model animal. Heart and respiratory rates, body temperature, eyelid reflex, digital pinch and metatarsal reflex were registered along with latency and ambulation times. Results The use of interspecific allometric scaling for chemical restraint with the combination tiletamine and zolazepam showed satisfying results, with great similarity to results obtained with conventional doses in Greater rheas. Conclusions Literature on chemical restraint and use of tiletamine and zolazepam in rheas is scarce. Chemical restraint is of extreme importance on these animals, due to their aggressive nature and low level of domesticity. This research may further establish the interspecific allometric scaling method as a viable tool for the veterinary physician in formulating anesthetic and chemical restraint protocols for wildlife animals. PMID:24625103

  17. Scaling and mechanics of the felid calcaneus: geometric similarity without differential allometric scaling

    PubMed Central

    Gálvez-López, Eloy; Casinos, Adrià

    2012-01-01

    Six mechanically significant skeletal variables were measured on the calcanei from 60 Felidae specimens (22 species) to determine whether these variables were scaled to body mass, and to assess whether differential scaling exists. The power equation (y = a · xb) was used to analyse the scaling of the six variables to body mass; we compared traditional regression methods (standardised major axis) to phylogenetically independent contrasts. In agreement with previous studies that compared these methodologies, we found no significant differences between methods in the allometric coefficients (b) obtained. Overall, the scaling pattern of the felid calcaneus conformed to the predictions of the geometric similarity hypothesis, but not entirely to those of the elastic similarity hypothesis. We found that the moment arm of the ankle extensors scaled to body mass with an exponent not significantly different from 0.40. This indicated that the tuber calcanei scaled to body mass faster than calcaneus total length. This explained why the effective mechanical advantage of the ankle extensors increased with body mass, despite the fact that limb posture does not change in felid species. Furthermore, this finding was consistent with the hypothesis of the isometric scaling of ground reaction forces. No evidence for differential scaling was found in any of the variables studied. We propose that this reflected the similar locomotor pattern of all felid species. Thus, our results suggested that the differences in allometric coefficients for ‘large’ and ‘small’ mammals were in fact caused by different types of locomotion among the species included in each category. PMID:22463377

  18. Scaling and mechanics of the felid calcaneus: geometric similarity without differential allometric scaling.

    PubMed

    Gálvez-López, Eloy; Casinos, Adrià

    2012-06-01

    Six mechanically significant skeletal variables were measured on the calcanei from 60 Felidae specimens (22 species) to determine whether these variables were scaled to body mass, and to assess whether differential scaling exists. The power equation (y = a · x(b) ) was used to analyse the scaling of the six variables to body mass; we compared traditional regression methods (standardised major axis) to phylogenetically independent contrasts. In agreement with previous studies that compared these methodologies, we found no significant differences between methods in the allometric coefficients (b) obtained. Overall, the scaling pattern of the felid calcaneus conformed to the predictions of the geometric similarity hypothesis, but not entirely to those of the elastic similarity hypothesis. We found that the moment arm of the ankle extensors scaled to body mass with an exponent not significantly different from 0.40. This indicated that the tuber calcanei scaled to body mass faster than calcaneus total length. This explained why the effective mechanical advantage of the ankle extensors increased with body mass, despite the fact that limb posture does not change in felid species. Furthermore, this finding was consistent with the hypothesis of the isometric scaling of ground reaction forces. No evidence for differential scaling was found in any of the variables studied. We propose that this reflected the similar locomotor pattern of all felid species. Thus, our results suggested that the differences in allometric coefficients for 'large' and 'small' mammals were in fact caused by different types of locomotion among the species included in each category. PMID:22463377

  19. Chronic nitrogen deposition alters tree allometric relationships: implications for biomass production and carbon storage.

    PubMed

    Ibáñez, Inés; Zak, Donald R; Burton, Andrew J; Pregitzer, Kurt S

    2016-04-01

    As increasing levels of nitrogen (N) deposition impact many terrestrial ecosystems, understanding the potential effects of higher N availability is critical for forecasting tree carbon allocation patterns and thus future forest productivity. Most regional estimates of forest biomass apply allometric equations, with parameters estimated from a limited number of studies, to forest inventory data (i.e., tree diameter). However most of these allometric equations cannot account for potential effects of increased N availability on biomass allocation patterns. Using 18 yr of tree diameter, height, and mortality data collected for a dominant tree species (Acer saccharum) in an atmospheric N deposition experiment, we evaluated how greater N availability affects allometric relationships in this species. After taking into account site and individual variability, our results reveal significant differences in allometric parameters between ambient and experimental N deposition treatments. Large trees under experimental N deposition reached greater heights at a given diameter; moreover, their estimated maximum height (mean ± standard deviation: 33.7 ± 0.38 m) was significantly higher than that estimated under the ambient condition (31.3 ± 0.31 m). Within small tree sizes (5-10 cm diameter) there was greater mortality under experimental N deposition, whereas the relative growth rates of small trees were greater under experimental N deposition. Calculations of stemwood biomass using our parameter estimates for the diameter-height relationship indicated the potential for significant biases in these estimates (~2.5%), with under predictions of stemwood biomass averaging 4 Mg/ha lower if ambient parameters were to be used to estimate stem biomass of trees in the experimental N deposition treatment. As atmospheric N deposition continues to increase into the future, ignoring changes in tree allometry will contribute to the uncertainty associated with aboveground carbon storage

  20. Allometric scaling of mammalian blood pressure: A comment on White and Seymour (2014).

    PubMed

    Packard, Gary C

    2015-12-01

    White and Seymour examined the scaling of central arterial blood pressure against body mass in mammals ranging in size from a 30 g mouse to a 4080 kg elephant. Exponents in power functions fitted to each of three datasets (systolic, diastolic, and mean arterial pressure) were reported to be significantly greater than zero and indistinguishable from 0.33. The first of these outcomes would indicate that blood pressure increases with body size, whereas the second is consistent with the heart working against gravity to move blood to the head. Taken together, these results seemingly refute the notion that the cephalic circulation functions as an energy-neutral siphon. However, the main findings by White and Seymour were presented in the form of graphs that distorted the relationships between the variables of interest. I use simple graphics to show that the data were unsuited from the outset for use in allometric analyses and that conclusions of the investigation are not well supported. PMID:26462730

  1. Trabecular bone scales allometrically in mammals and birds

    PubMed Central

    Doube, Michael; Kłosowski, Michał M.; Wiktorowicz-Conroy, Alexis M.; Hutchinson, John R.; Shefelbine, Sandra J.

    2011-01-01

    Many bones are supported internally by a latticework of trabeculae. Scaling of whole bone length and diameter has been extensively investigated, but scaling of the trabecular network is not well characterized. We analysed trabecular geometry in the femora of 90 terrestrial mammalian and avian species with body masses ranging from 3 g to 3400 kg. We found that bone volume fraction does not scale substantially with animal size, while trabeculae in larger animals' femora are thicker, further apart and fewer per unit volume than in smaller animals. Finite element modelling indicates that trabecular scaling does not alter the bulk stiffness of trabecular bone, but does alter strain within trabeculae under equal applied loads. Allometry of bone's trabecular tissue may contribute to the skeleton's ability to withstand load, without incurring the physiological or mechanical costs of increasing bone mass. PMID:21389033

  2. Constraint around Quarter-Power Allometric Scaling in Wild Tomatoes (Solanum sect. Lycopersicon; Solanaceae).

    PubMed

    Muir, Christopher D; Thomas-Huebner, Meret

    2015-09-01

    The West-Brown-Enquist (WBE) metabolic scaling theory posits that many organismal features scale predictably with body size because of selection to minimize transport costs in resource distribution networks. Many scaling exponents are quarter-powers, as predicted by WBE, but there are also biologically significant deviations that could reflect adaptation to different environments. A central but untested prediction of the WBE model is that wide deviation from optimal scaling is penalized, leading to a pattern of constraint on scaling exponents. Here, we demonstrate, using phylogenetic comparative methods, that variation in allometric scaling between mass and leaf area across 17 wild tomato taxa is constrained around a value indistinguishable from that predicted by WBE but significantly greater than 2/3 (geometric-similarity model). The allometric-scaling exponent was highly correlated with fecundity, water use, and drought response, suggesting that it is functionally significant and therefore could be under selective constraints. However, scaling was not strictly log-log linear but rather declined during ontogeny in all species, as has been observed in many plant species. We caution that although our results supported one prediction of the WBE model, it did not strongly test the model in other important respects. Nevertheless, phylogenetic comparative methods such as those used here are powerful but underutilized tools for metabolic ecology that complement existing methods to adjudicate between models. PMID:26655358

  3. An Invariant Allometric Scaling of Nitrogen and Phosphorus in Leaves, Stems and Fine roots Along an Altitudinal Gradient

    NASA Astrophysics Data System (ADS)

    Zhao, Ning; He, Nianpeng; Wang, Qiufeng; Wang, Ruili; Xu, Zhiwei; YU, Guirui

    2014-05-01

    Plant nutrient allocation explicitly links the plant resource capture strategy to the material and energy cycles of ecosystems. The nitrogen (N) to phosphorus (P) relationship in plant organs is of particular interest, as N and P are the major limiting elements for plant growth. Here we analyze the relations of N and P in leaves, stems and fine roots of 269 species along an altitudinal transect on the northern slope of Changbai Mountain, China, to explore the partitioning of nutrients in major plant organs and its response to environmental gradient. We find that N, P contents as well as N: P ratio are significantly higher in leaves than in stems and fine roots. Nutrient contents of major plant organs show consistent response to the altitudinal gradient. N and P contents of leaves, stems and fine roots increased while N:P ratios decreased with elevation. Moreover, general allometric scaling relations of N and P is found in leaves, stems and fine roots with slopes of 0.78, 0.72 and 0.87, respectively, and differences exist among different plant growth forms. In general, the exponent values of the allometric scaling of N and P in leaves, stems and fine roots keep as an invariant constant along the altitudinal gradient, which implies the existence of conserved nutrient allocation strategies in plant.

  4. Left ventricular mass: allometric scaling, normative values, effect of obesity, and prognostic performance.

    PubMed

    Chirinos, Julio A; Segers, Patrick; De Buyzere, Marc L; Kronmal, Richard A; Raja, Muhammad W; De Bacquer, Dirk; Claessens, Tom; Gillebert, Thierry C; St John-Sutton, Martin; Rietzschel, Ernst R

    2010-07-01

    The need for left ventricular mass (LVM) normalization to body size is well recognized. Currently used allometric exponents to normalize LVM may not account for the confounding effect of sex. Because sex is a strong determinant of body size and LVM, we hypothesized that these are subject to potential bias. We analyzed data from 7528 subjects enrolled in the Asklepios Study (n=2524) and the Multiethnic Study of Atherosclerosis (limited access data set; n=5,004) to assess metric relationships between LVM and body size, generate normative data for indexed LVM, and compare the ability of normalization methods to predict cardiovascular events. The allometric exponent that adequately described the LVM-body height relationship was 1.7 in both studies and significantly different from both the unity and 2.7, whereas the LVM-body surface area relationship was approximately linear. LVM/height(2.7) consistently demonstrated important residual relationships with body height and systematically misclassified subjects regarding the presence of LVH. LVH defined by LVM/height(1.7) was more sensitive than LVM/body surface area to identify obesity-related LVH and was most consistently associated with cardiovascular events and all-cause death. In contrast to current assumptions, LVM/height(2.7) is not an adequate method to normalize LVM for body size. We provide more appropriate normalization methods, normative data by 2D echocardiography and gradient-echo cardiac MRI, and cutoffs for defining LVH, along with prognostic validation data. PMID:20458004

  5. Differences in left ventricular long-axis function from mice to humans follow allometric scaling to ventricular size.

    PubMed

    Popović, Zoran B; Sun, Jing Ping; Yamada, Hirotsugu; Drinko, Jeannie; Mauer, Karin; Greenberg, Neil L; Cheng, Yuanna; Moravec, Christine S; Penn, Marc S; Mazgalev, Todor N; Thomas, James D

    2005-10-01

    While the heart size maintains a constant proportion to body size, heart function parameters, such as heart rate and cardiac output, show a more complex scaling pattern. How these phenomena affect the long-axis left ventricular (LV) function is unknown. We studied 10 mice, 15 rats, 6 rabbits, 8 mongrel dogs and 38 human volunteers. Doppler tissue echocardiography data were postprocessed to reconstruct mitral annulus (MA) peak systolic velocity and displacement. The relationship between MA peak velocity, MA displacement and LV ejection time, and LV end-diastolic volume (and mass) were fit to an allometric (power-law) equation Y=kMbeta. LV mass varied from 0.062 to 255 g, while end-diastolic volume varied from 0.014 to 205 ml. beta values of the relation between LV ejection time and LV end-diastolic volume and mass were 0.247+/-0.017 and 0.267+/-0.018, respectively. beta values of the relationship between MA displacement and LV end-diastolic volume and mass were 0.358+/-0.047 and 0.390+/-0.051 (P<0.023 versus beta of LV ejection time). beta values of the relationship between MA peak systolic velocity and LV end-diastolic volume and mass were 0.096+/-0.012 and 0.100+/-0.013, respectively (P<0.0001 versus 0). Finally, beta values of the relationship between the long-to-short axis displacement ratio and LV end-diastolic volume and mass were 0.077+/-0.017 and 0.086+/-0.019 (P<0.0001 versus 0). We conclude that MA velocity, displacement, and long-to-short axis displacement ratio scale allometrically to heart size. This reduces the relative long-axis contribution to heart function in small mammals. PMID:16002448

  6. Anatomical and physiological basis for the allometric scaling of cisplatin clearance in dogs.

    PubMed

    Achanta, S; Sewell, A; Ritchey, J W; Broaddus, K; Bourne, D W A; Clarke, C R; Maxwell, L K

    2016-06-01

    Cisplatin is a platinum-containing cytotoxic drug indicated for the treatment of solid tumors in veterinary and human patients. Several of the algorithms used to standardize the doses of cytotoxic drugs utilize allometry, or the nonproportional relationships between anatomical and physiological variables, but the underlying basis for these relationships is poorly understood. The objective of this proof of concept study was to determine whether allometric equations explain the relationships between body weight, kidney weight, renal physiology, and clearance of a model, renally cleared anticancer agent in dogs. Postmortem body, kidney, and heart weights were collected from 364 dogs (127 juveniles and 237 adults, including 51 dogs ≥ 8 years of age). Renal physiological and cisplatin pharmacokinetic studies were conducted in ten intact male dogs including two juvenile and eight adult dogs (4-55 kg). Glomerular filtration rate (GFR), effective renal plasma flow, effective renal blood flow, renal cisplatin clearance, and total cisplatin clearance were allometrically related to body weight with powers of 0.75, 0.59, 0.61, 0.71, and 0.70, respectively. The similar values of these diverse mass exponents suggest a common underlying basis for the allometry of kidney size, renal physiology, and renal drug handling. PMID:26440900

  7. Allometric relationships between the length of pregnancy and body parameters in mammals

    NASA Astrophysics Data System (ADS)

    Atanasov, A. T.; Todorova, M.; Valev, D. T.; Todorova, R.

    2014-10-01

    In this manuscript we investigated the presence of allometric relationships between the length of pregnancy and the body parameters in mammals. The relationships between the length of pregnancy T (d) and the square of body length H2 (m2), body surface S (m2), body mass to surface ratio M/S (kg/m2) and body-mass index (BMI) (M/H2) were investigated in mammals: Metatheria and Placentalia, including animals with body mass ranging from 8g in Common shrew to 15t in Killer whale. In result, the found power equations are: T = 114.3 (H2)0.352; T= 120.4 S0.38; T = 9.147 (M/S)0.757 and T = 17.6 BMI0.605. The study showed that the M/S ratio and BMI are nearly equivalent characteristics in relation to length of pregnancy.

  8. Fifth dimension of life and the 4/5 allometric scaling law for human brain.

    PubMed

    He, Ji-Huan; Zhang, Juan

    2004-01-01

    Brain cells are not spherical. The basal metabolic rate (B) of a spherical cell scales as B approximately r2, where r is the radius of the cell; that of a brain cell scales as B approximately r(d), where r is the characteristic radius of the cell and d is the fractal dimensionality of its contour. The fractal geometry of the cell leads to a 4/5 allometric scaling law for human brain, uniquely endowing humans with a 5th dimension and successfully explains why the scaling exponent varies during rest and exercise. A striking analogy between Kleiber's 3/4 law and Newton's second law is heuristically illustrated. A physical explanation is given for the 4th dimension of life for three-dimensional organisms and the 5th dimension for human brain. PMID:15563403

  9. Languages cool as they expand: Allometric scaling and the decreasing need for new words

    PubMed Central

    Petersen, Alexander M.; Tenenbaum, Joel N.; Havlin, Shlomo; Stanley, H. Eugene; Perc, Matjaž

    2012-01-01

    We analyze the occurrence frequencies of over 15 million words recorded in millions of books published during the past two centuries in seven different languages. For all languages and chronological subsets of the data we confirm that two scaling regimes characterize the word frequency distributions, with only the more common words obeying the classic Zipf law. Using corpora of unprecedented size, we test the allometric scaling relation between the corpus size and the vocabulary size of growing languages to demonstrate a decreasing marginal need for new words, a feature that is likely related to the underlying correlations between words. We calculate the annual growth fluctuations of word use which has a decreasing trend as the corpus size increases, indicating a slowdown in linguistic evolution following language expansion. This “cooling pattern” forms the basis of a third statistical regularity, which unlike the Zipf and the Heaps law, is dynamical in nature. PMID:23230508

  10. Musculoskeletal determinants of pelvic sucker function in Hawaiian stream gobiid fishes: interspecific comparisons and allometric scaling.

    PubMed

    Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

    2013-07-01

    Gobiid fishes possess a distinctive ventral sucker, formed from fusion of the pelvic fins. This sucker is used to adhere to a wide range of substrates including, in some species, the vertical cliffs of waterfalls that are climbed during upstream migrations. Previous studies of waterfall-climbing goby species have found that pressure differentials and adhesive forces generated by the sucker increase with positive allometry as fish grow in size, despite isometry or negative allometry of sucker area. To produce such scaling patterns for pressure differential and adhesive force, waterfall-climbing gobies might exhibit allometry for other muscular or skeletal components of the pelvic sucker that contribute to its adhesive function. In this study, we used anatomical dissections and modeling to evaluate the potential for allometric growth in the cross-sectional area, effective mechanical advantage (EMA), and force generating capacity of major protractor and retractor muscles of the pelvic sucker (m. protractor ischii and m. retractor ischii) that help to expand the sealed volume of the sucker to produce pressure differentials and adhesive force. We compared patterns for three Hawaiian gobiid species: a nonclimber (Stenogobius hawaiiensis), an ontogenetically limited climber (Awaous guamensis), and a proficient climber (Sicyopterus stimpsoni). Scaling patterns were relatively similar for all three species, typically exhibiting isometric or negatively allometric scaling for the muscles and lever systems examined. Although these scaling patterns do not help to explain the positive allometry of pressure differentials and adhesive force as climbing gobies grow, the best climber among the species we compared, S. stimpsoni, does exhibit the highest calculated estimates of EMA, muscular input force, and output force for pelvic sucker retraction at any body size, potentially facilitating its adhesive ability. PMID:23450656

  11. Consistent allometric scaling of stomatal sizes and densities across taxonomic ranks and geologic time

    NASA Astrophysics Data System (ADS)

    de Boer, H. J.; Price, C. A.; Wagner-Cremer, F.; Dekker, S. C.; Veneklaas, E. J.

    2013-12-01

    Stomatal pores on plants leaves are an important link in the chain of processes that determine biosphere fluxes of water and carbon. Stomatal density (i.e. the number of stomata per area) and the size of the stomatal pore at maximum aperture are particularly relevant traits in this context because they determine the theoretical maximum diffusive stomatal conductance (gsmax) and thereby set an upper limit for leaf gas exchange. Observations on (sub)fossil leaves revealed that changes in stomatal densities are anti-correlated with changes in stomatal sizes at developmental and evolutionary timescales. Moreover, this anti-correlation appears consistently within single species, across multiple species in the extant plant community and at evolutionary time scales. The consistency of the relation between stomatal densities and sizes suggests that common mechanisms constrain the adaptation of these traits across the plant community. In an attempt to identify such potential generic constraints, we investigated the allometry between stomatal densities and sizes in the extant plant community and across geological time. As the size of the stomatal pore at maximum aperture is typically derived from the length of the stomatal pore, we considered the allometric scaling of pore length (lp) with stomatal density (Ds) as the power law: lp = k . Dsa in which k is a normalization constant and the exponent a is the slope of the scaling relation. Our null-hypothesis predicts that stomatal density and pore length scale along a constant slope of -1/2 based on a scale-invariant relation between pore length and the distance between neighboring pores. Our alternative hypothesis predicts a constant slope of -1 based on the idea that stomatal density and pore length scale along an invariant gsmax. To explore these scaling hypotheses in the extant plant community we compiled a dataset of combined observations of stomatal density and pore length on 111 species from published literature and new

  12. Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

    NASA Astrophysics Data System (ADS)

    CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

    2013-12-01

    Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

  13. Allometric scaling of discontinuous gas exchange patterns in the locust Locusta migratoria throughout ontogeny.

    PubMed

    Snelling, Edward P; Matthews, Philip G D; Seymour, Roger S

    2012-10-01

    The discontinuous gas exchange cycle (DGC) is a three-phase breathing pattern displayed by many insects at rest. The pattern consists of an extended breath-hold period (closed phase), followed by a sequence of rapid gas exchange pulses (flutter phase), and then a period in which respiratory gases move freely between insect and environment (open phase). This study measured CO(2) emission in resting locusts Locusta migratoria throughout ontogeny, in normoxia (21 kPa P(O2)), hypoxia (7 kPa P(O2)) and hyperoxia (40 kPa P(O2)), to determine whether body mass and ambient O(2) affect DGC phase duration. In normoxia, mean CO(2) production rate scales with body mass (M(b); g) according to the allometric power equation , closed phase duration (C; min) scales with body mass according to the equation C=8.0M(b)(0.38±0.29), closed+flutter period (C+F; min) scales with body mass according to the equation C+F=26.6M (0.20±0.25)(b) and open phase duration (O; min) scales with body mass according to the equation O=13.3M(b) (0.23±0.18). Hypoxia results in a shorter C phase and longer O phase across all life stages, whereas hyperoxia elicits shorter C, C+F and O phases across all life stages. The tendency for larger locusts to exhibit longer C and C+F phases might arise if the positive allometric scaling of locust tracheal volume prolongs the time taken to reach the minimum O(2) and maximum CO(2) set-points that determine the duration of these respective periods, whereas an increasingly protracted O phase could reflect the additional time required for larger locusts to expel CO(2) through a relatively longer tracheal pathway. Observed changes in phase duration under hypoxia possibly serve to maximise O(2) uptake from the environment, whereas the response of the DGC to hyperoxia is difficult to explain, but could be affected by elevated levels of reactive oxygen species. PMID:22735346

  14. Abnormal Cortical Development after Premature Birth Shown by Altered Allometric Scaling of Brain Growth

    PubMed Central

    Kapellou, Olga; Counsell, Serena J; Kennea, Nigel; Dyet, Leigh; Saeed, Nadeem; Stark, Jaroslav; Maalouf, Elia; Duggan, Philip; Ajayi-Obe, Morenike; Hajnal, Jo; Allsop, Joanna M; Boardman, James; Rutherford, Mary A; Cowan, Frances; Edwards, A. David

    2006-01-01

    Background We postulated that during ontogenesis cortical surface area and cerebral volume are related by a scaling law whose exponent gives a quantitative measure of cortical development. We used this approach to investigate the hypothesis that premature termination of the intrauterine environment by preterm birth reduces cortical development in a dose-dependent manner, providing a neural substrate for functional impairment. Methods and Findings We analyzed 274 magnetic resonance images that recorded brain growth from 23 to 48 wk of gestation in 113 extremely preterm infants born at 22 to 29 wk of gestation, 63 of whom underwent neurodevelopmental assessment at a median age of 2 y. Cortical surface area was related to cerebral volume by a scaling law with an exponent of 1.29 (95% confidence interval, 1.25–1.33), which was proportional to later neurodevelopmental impairment. Increasing prematurity and male gender were associated with a lower scaling exponent (p < 0.0001) independent of intrauterine or postnatal somatic growth. Conclusions Human brain growth obeys an allometric scaling relation that is disrupted by preterm birth in a dose-dependent, sexually dimorphic fashion that directly parallels the incidence of neurodevelopmental impairments in preterm infants. This result focuses attention on brain growth and cortical development during the weeks following preterm delivery as a neural substrate for neurodevelopmental impairment after premature delivery. PMID:16866579

  15. Allometric scaling of UK urban emissions: interpretation and implications for air quality management

    NASA Astrophysics Data System (ADS)

    MacKenzie, Rob; Barnes, Matt; Whyatt, Duncan; Hewitt, Nick

    2016-04-01

    Allometry uncovers structures and patterns by relating the characteristics of complex systems to a measure of scale. We present an allometric analysis of air quality for UK urban settlements, beginning with emissions and moving on to consider air concentrations. We consider both airshed-average 'urban background' concentrations (cf. those derived from satellites for NO2) and local pollution 'hotspots'. We show that there is a strong and robust scaling (with respect to population) of the non-point-source emissions of the greenhouse gases carbon dioxide and methane, as well as the toxic pollutants nitrogen dioxide, PM2.5, and 1,3-butadiene. The scaling of traffic-related emissions is not simply a reflection of road length, but rather results from the socio-economic patterning of road-use. The recent controversy regarding diesel vehicle emissions is germane to our study but does not affect our overall conclusions. We next develop an hypothesis for the population-scaling of airshed-average air concentrations, with which we demonstrate that, although average air quality is expected to be worse in large urban centres compared to small urban centres, the overall effect is an economy of scale (i.e., large cities reduce the overall burden of emissions compared to the same population spread over many smaller urban settlements). Our hypothesis explains satellite-derived observations of airshed-average urban NO2 concentrations. The theory derived also explains which properties of nature-based solutions (urban greening) can make a significant contribution at city scale, and points to a hitherto unforeseen opportunity to make large cities cleaner than smaller cities in absolute terms with respect to their airshed-average pollutant concentration.

  16. Comparison of lung volume in Greek swimmers, land based athletes, and sedentary controls using allometric scaling.

    PubMed Central

    Doherty, M; Dimitriou, L

    1997-01-01

    OBJECTIVE: To compare lung volumes in a large cross sectional sample of Greek swimmers, land based athletes, and sedentary controls by means of allometric scaling. METHODS: Four hundred and fifty nine asymptomatic Greek children and young adults (age 10-21 years), including 159 swimmers, 130 land based athletes, and 170 sedentary controls, performed forced expiratory manoeuvres into a portable spirometer. Measurements included forced vital capacity, forced expiratory volume in one second (FEV1.0), and peak expiratory flow. Body mass and stature were also measured using standardised anthropometric techniques. RESULTS: Logarithmic transformations showed that in FEV1.0 was highly related to in stature in males and females (r = 0.93 and 0.86 respectively, P < 0.001) and were used to determine the exponent in an allometric equation which also included age and age. Resulting power functions, FEV1.0/stature, were 0.64 (0.18) litres/m2.69 and 0.33 (0.24) litres/m2.32 for males and females respectively (mean (SE)). The male and female swimming groups had larger FEV1.0 than both land based athletes and sedentary controls (one way analysis of variance, P < 0.001). In addition, male national standard swimmers (n = 38) had superior FEV1.0 in comparison with male non-national standard swimmers (n = 24; t test, P < 0.05). However, when years of swimming training was controlled for by analysis of covariance, the difference in FEV1.0 between the two groups was no longer evident. CONCLUSIONS: Swimmers have superior FEV1.0 independent of stature and age in comparison with both land based athletes and sedentary controls. In addition, male national standard swimmers have superior FEV1.0 independent of stature and age in comparison with male non-national standard swimmers. When years of training is controlled for, the difference in FEV1.0 between the two groups is no longer evident. This suggests that the years of swimming training and/or the earlier age at which training begins may

  17. Comparative Pharmacokinetics and Allometric Scaling of Carboplatin in Different Avian Species

    PubMed Central

    De Baere, Siegrid; Hellebuyck, Tom; Van de Maele, Isabel; Rouffaer, Lieze; Stemkens, Hendrickus J. J.; De Backer, Patrick; Martel, An; Croubels, Siska

    2015-01-01

    The use of chemotherapeutics as a possible treatment strategy in avian oncology is steadily increasing over the last years. Despite this, literature reports regarding dosing strategies and pharmacokinetic behaviour of chemotherapeutics in avian species are lacking. The aim of the present study was to investigate the pharmacokinetics of carboplatin in a representative species of the order of Galliformes, Anseriformes, Columbiformes and Psittaciformes. Eight chickens, ducks and pigeons and twenty-eight parakeets were administered carboplatin intravenously (5 mg/kg body weight). A specific and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of the free carboplatin in plasma of the four birds species (limit of quantification: 20 ng/mL for chicken and duck, 50 ng/mL for pigeon and 100 ng/mL for parakeets). Non-compartmental pharmacokinetic analysis and allometric scaling demonstrated a significant correlation (R² = 0.9769) between body weight (BW) and elimination half-life (T1/2el). T1/2el ranged from 0.41 h in parakeets (BW: 61 ± 8 g) to 1.16 h chickens (BW: 1909 ± 619 g). T1/2el is a good parameter for dose optimization of carboplatin in other avian species, since also the previously reported T1/2el in cockatoos (average BW: 769 ± 68 g) of 1.00 h corresponds to the results obtained in the present study. PMID:26222777

  18. Comparative Pharmacokinetics and Allometric Scaling of Carboplatin in Different Avian Species.

    PubMed

    Antonissen, Gunther; Devreese, Mathias; De Baere, Siegrid; Hellebuyck, Tom; Van de Maele, Isabel; Rouffaer, Lieze; Stemkens, Hendrickus J J; De Backer, Patrick; Martel, An; Croubels, Siska

    2015-01-01

    The use of chemotherapeutics as a possible treatment strategy in avian oncology is steadily increasing over the last years. Despite this, literature reports regarding dosing strategies and pharmacokinetic behaviour of chemotherapeutics in avian species are lacking. The aim of the present study was to investigate the pharmacokinetics of carboplatin in a representative species of the order of Galliformes, Anseriformes, Columbiformes and Psittaciformes. Eight chickens, ducks and pigeons and twenty-eight parakeets were administered carboplatin intravenously (5 mg/kg body weight). A specific and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of the free carboplatin in plasma of the four birds species (limit of quantification: 20 ng/mL for chicken and duck, 50 ng/mL for pigeon and 100 ng/mL for parakeets). Non-compartmental pharmacokinetic analysis and allometric scaling demonstrated a significant correlation (R² = 0.9769) between body weight (BW) and elimination half-life (T1/2el). T1/2el ranged from 0.41 h in parakeets (BW: 61 ± 8 g) to 1.16 h chickens (BW: 1909 ± 619 g). T1/2el is a good parameter for dose optimization of carboplatin in other avian species, since also the previously reported T1/2el in cockatoos (average BW: 769 ± 68 g) of 1.00 h corresponds to the results obtained in the present study. PMID:26222777

  19. Interspecies allometric scaling. Part I: prediction of clearance in large animals.

    PubMed

    Mahmood, I; Martinez, M; Hunter, R P

    2006-10-01

    Interspecies scaling is a useful tool for the prediction of pharmacokinetic parameters from animals to humans, and it is often used for estimating a first-time in human dose. The knowledge of pharmacokinetics in veterinary species is important for dosage selection, particularly in the treatment of large zoo animal species, such as elephants, giant cats and camels, for which pharmacokinetic data are scant. Therefore, the accuracy in clearance predictions in large animal species, with and without the use of correction factors (rule of exponents), and the impact of species selection in the prediction of clearance in large animal species was examined. Based upon this analysis, it was determined that there is a much larger risk of inaccuracies in the clearance estimates in large animal species when compared with that observed for humans. Unlike in humans, for large animal species, correction factors could not be applied because there was no trend between the exponents of simple allometry and the appropriate correction factor for improving our predictions. Nevertheless, we did see an indication that the exponents of simple allometry may alert us as to when the predicted clearance in the large animal may be underestimated or overpredicted. For example, if a large animal is included in the scaling, the predicted clearance in a large animal should be considered overestimated if the exponent of simple allometry is >1.3. Despite the potential for extrapolation error, the reality is that allometric scaling is needed across many veterinary practice situations, and therefore will be used. For this reason, it is important to consider mechanisms for reducing the risk of extrapolation errors that can seriously affect target animal safety, therapeutic response, or the accuracy of withdrawal time predictions. PMID:16958787

  20. ALLOMETRIC LENGTH-WEIGHT RELATIONSHIPS FOR BENTHIC PREY OF AQUATIC WILDLIFE IN COASTAL MARINE HABITATS

    EPA Science Inventory

    We developed models to estimate the soft tissue content of benthic marine invertebrates that are prey for aquatic wildlife. Allometric regression models of tissue wet weight with shell length for 10 species of benthic invertebrates had r2 values ranging from 0.29 for hermit crabs...

  1. Impact of methodology and the use of allometric scaling on the echocardiographic assessment of the aortic root and arch: a study by the Research and Audit Sub-Committee of the British Society of Echocardiography.

    PubMed

    Oxborough, David; Ghani, Saqib; Harkness, Allan; Lloyd, Guy; Moody, William; Ring, Liam; Sandoval, Julie; Senior, Roxy; Sheikh, Nabeel; Stout, Martin; Utomi, Victor; Willis, James; Zaidi, Abbas; Steeds, Richard

    2014-09-01

    The aim of the study is to establish the impact of 2D echocardiographic methods on absolute values for aortic root dimensions and to describe any allometric relationship to body size. We adopted a nationwide cross-sectional prospective multicentre design using images obtained from studies utilising control groups or where specific normality was being assessed. A total of 248 participants were enrolled with no history of cardiovascular disease, diabetes, hypertension or abnormal findings on echocardiography. Aortic root dimensions were measured at the annulus, the sinus of Valsalva, the sinotubular junction, the proximal ascending aorta and the aortic arch using the inner edge and leading edge methods in both diastole and systole by 2D echocardiography. All dimensions were scaled allometrically to body surface area (BSA), height and pulmonary artery diameter. For all parameters with the exception of the aortic annulus, dimensions were significantly larger in systole (P<0.05). All aortic root and arch measurements were significantly larger when measured using the leading edge method compared with the inner edge method (P<0.05). Allometric scaling provided a b exponent of BSA(0.6) in order to achieve size independence. Similarly, ratio scaling to height in subjects under the age of 40 years also produced size independence. In conclusion, the largest aortic dimensions occur in systole while using the leading edge method. Reproducibility of measurement, however, is better when assessing aortic dimensions in diastole. There is an allometric relationship to BSA and, therefore, allometric scaling in the order of BSA(0.6) provides a size-independent index that is not influenced by the age or gender. PMID:26693286

  2. Jellyfish Body Plans Provide Allometric Advantages beyond Low Carbon Content

    PubMed Central

    Pitt, Kylie A.; Duarte, Carlos M.; Lucas, Cathy H.; Sutherland, Kelly R.; Condon, Robert H.; Mianzan, Hermes; Purcell, Jennifer E.; Robinson, Kelly L.; Uye, Shin-Ichi

    2013-01-01

    Jellyfish form spectacular blooms throughout the world’s oceans. Jellyfish body plans are characterised by high water and low carbon contents which enables them to grow much larger than non-gelatinous animals of equivalent carbon content and to deviate from non-gelatinous pelagic animals when incorporated into allometric relationships. Jellyfish have, however, been argued to conform to allometric relationships when carbon content is used as the metric for comparison. Here we test the hypothesis that differences in allometric relationships for several key functional parameters remain for jellyfish even after their body sizes are scaled to their carbon content. Data on carbon and nitrogen contents, rates of respiration, excretion, growth, longevity and swimming velocity of jellyfish and other pelagic animals were assembled. Allometric relationships between each variable and the equivalent spherical diameters of jellyfish and other pelagic animals were compared before and after sizes of jellyfish were standardised for their carbon content. Before standardisation, the slopes of the allometric relationships for respiration, excretion and growth were the same for jellyfish and other pelagic taxa but the intercepts differed. After standardisation, slopes and intercepts for respiration were similar but excretion rates of jellyfish were 10× slower, and growth rates 2× faster than those of other pelagic animals. Longevity of jellyfish was independent of size. The slope of the allometric relationship of swimming velocity of jellyfish differed from that of other pelagic animals but because they are larger jellyfish operate at Reynolds numbers approximately 10× greater than those of other pelagic animals of comparable carbon content. We conclude that low carbon and high water contents alone do not explain the differences in the intercepts or slopes of the allometric relationships of jellyfish and other pelagic animals and that the evolutionary longevity of jellyfish and

  3. The allometric exponent for scaling clearance varies with age: a study on seven propofol datasets ranging from preterm neonates to adults

    PubMed Central

    Wang, Chenguang; Allegaert, Karel; Peeters, Mariska Y M; Tibboel, Dick; Danhof, Meindert; Knibbe, Catherijne A J

    2014-01-01

    Aim For scaling clearance between adults and children, allometric scaling with a fixed exponent of 0.75 is often applied. In this analysis, we performed a systematic study on the allometric exponent for scaling propofol clearance between two subpopulations selected from neonates, infants, toddlers, children, adolescents and adults. Methods Seven propofol studies were included in the analysis (neonates, infants, toddlers, children, adolescents, adults1 and adults2). In a systematic manner, two out of the six study populations were selected resulting in 15 combined datasets. In addition, the data of the seven studies were regrouped into five age groups (FDA Guidance 1998), from which four combined datasets were prepared consisting of one paediatric age group and the adult group. In each of these 19 combined datasets, the allometric scaling exponent for clearance was estimated using population pharmacokinetic modelling (nonmem 7.2). Results The allometric exponent for propofol clearance varied between 1.11 and 2.01 in cases where the neonate dataset was included. When two paediatric datasets were analyzed, the exponent varied between 0.2 and 2.01, while it varied between 0.56 and 0.81 when the adult population and a paediatric dataset except for neonates were selected. Scaling from adults to adolescents, children, infants and neonates resulted in exponents of 0.74, 0.70, 0.60 and 1.11 respectively. Conclusions For scaling clearance, ¾ allometric scaling may be of value for scaling between adults and adolescents or children, while it can neither be used for neonates nor for two paediatric populations. For scaling to neonates an exponent between 1 and 2 was identified. PMID:23772816

  4. The allometric model in chronic myocardial infarction

    PubMed Central

    2012-01-01

    Background An allometric relationship between different electrocardiogram (ECG) parameters and infarcted ventricular mass was assessed in a myocardial infarction (MI) model in New Zealand rabbits. Methods A total of fifteen animals were used, out of which ten underwent left anterior descending coronary artery ligation to induce infarction (7–35% area). Myocardial infarction (MI) evolved and stabilized during a three month-period, after which, rabbits were sacrificed and the injured area was histologically confirmed. Right before sacrifice, ECGs were obtained to correlate several of its parameters to the infarcted mass. The latter was normalized after combining data from planimetry measurements and heart weight. The following ECG parameters were studied: RR and PR intervals, P-wave duration (PD), QRS duration (QRSD) and amplitude (QRSA), Q-wave (QA), R-wave (RA) and S-wave (SA) amplitudes, T-wave peak amplitude (TA), the interval from the peak to the end of the T-wave (TPE), ST-segment deviation (STA), QT interval (QT), corrected QT and JT intervals. Corrected QT was analyzed with different correction formulae, i.e., Bazett (QTB), Framingham (QTFRA), Fridericia (QTFRI), Hodge (QTHO) and Matsunaga (QTMA) and compared thereafter. The former variables and infarcted ventricular mass were then fitted to the allometric equation in terms of deviation from normality, in turn derived after ECGs in 5 healthy rabbits. Results Six variables (JT, QTB, QA, SA, TA and STA) presented statistical differences among leads. QT showed the best allometric fit (r = 0.78), followed by TA (r = 0.77), STA (r = 0.75), QTFRA (r = 0.72), TPE (r = 0.69), QTFRI (r = 0.68) and QTMA (r = 0.68). Corrected QT’s (QTFRA, QTFRI and QTMA) performed worse than the uncorrected counterpart (QT), the former scaling allometrically with similar goodness of fits. Conclusions QT, TA, STA and TPE could possibly be used to assess infarction extent in an old MI event through the

  5. Allometric scaling and proportion regulation in the freshwater planarian Schmidtea mediterranea.

    PubMed

    Oviedo, Néstor J; Newmark, Phillip A; Sánchez Alvarado, Alejandro

    2003-02-01

    The regulation of scale and proportion in living organisms is an intriguing and enduring problem of biology. Regulatory mechanisms for controlling body size and proportion are clearly illustrated by the regeneration of missing body parts after amputation, in which the newly regenerated tissues ultimately attain a size that is anatomically congruent with the size of the rest of the organism. Understanding the molecular processes underpinning scaling would have deep consequences for our comprehension of tissue regeneration, developmental ontogeny, growth, and evolution. Although many theories have been put forward to explain this process, it is interesting that no satisfactory mechanistic explanation is currently available to explain scalar relationships. We chose to investigate the freshwater planarian, a commonly used model system for the study of metazoan regeneration, to delineate a strategy for the molecular dissection of scale and proportion mechanisms in metazoans. Here, we report on the cloning and discrete expression pattern of a novel planarian gene, which shares homology with the DEG/ENaC super-family of sodium channels. We have named H.112.3c cintillo ("head ribbon" in Spanish) and present a strategy for using the expression of this gene to monitor scale and proportion regulation during regeneration, growth and degrowth in the freshwater planarian Schmidtea mediterranea. PMID:12557210

  6. Trabecular bone microstructure scales allometrically in the primate humerus and femur

    PubMed Central

    Ryan, Timothy M.; Shaw, Colin N.

    2013-01-01

    Most analyses of trabecular microarchitecture in mammals have focused on the functional significance of interspecific variation, but they have not effectively considered the influence of body size or phylogeny on bone architecture. The goals of this study were to determine the relationship between trabecular bone and body size in the humeral and femoral heads of extant primates, and to assess the influence of phylogeny on bone microstructure. Using a sample of 235 individuals from 34 primate species, ranging in body size from 0.06 to 130 kg, the relationships between trabecular bone structure and body size were assessed by using conventional and phylogenetic regression analyses. Bone volume fraction, trabecular thickness and trabecular spacing increase with body size, whereas bone surface-area-to-volume ratio decreases. Shape variables such as trabecular number, connectivity density and degree of anisotropy scale inversely with size. Most of these variables scale with significant negative allometry, except bone surface-area-to-volume ratio, which scales with slight positive allometry. Phylogenetic regressions indicate a relatively weak phylogenetic signal in some trabecular bone variables. These data demonstrate that, relative to body size, large primates have thinner and more tightly packed trabeculae than small primates. The relatively thin trabeculae in large primates and other mammals, coupled with constraints on trabecular thickness related to osteocyte function, suggest that increased skeletal loads in the postcranial joints of large mammals are probably mitigated not only through alterations in trabecular microarchitecture, but also through other mechanisms such as changes in cortical bone distribution, limb posture and gait speed. PMID:23486443

  7. Allometric Relationships in Soybean to Estimate the Effect of Vegetation on Microwave Remote Sensing

    NASA Astrophysics Data System (ADS)

    Spencer, A. J.; Hornbuckle, B. K.; Patton, J.

    2011-12-01

    content and dry mass may lead to the use of microwave remote sensing to estimate yield. Our models displayed a strong linear relationship between Zc*Sd2 and vegetation water content with each variable defined on a logarithmic scale. The R2 values gathered after ten soybean sampling days over a ten week period never dropped below 0.65 and three times displayed a R2 value of 0.94 and higher, with an average value of 0.82. We also found that the percentage change in vegetation water content varies only slightly from the second vegetative stage to the fourth reproductive stage. Further research into whether these changes are significant is ongoing. With this new information, we hope to improve in-situ measurements of vegetation water content and work towards the goal of estimating yield from space before harvest.

  8. Predicting Maximum Tree Heights and Other Traits from Allometric Scaling and Resource Limitations

    PubMed Central

    Kempes, Christopher P.; West, Geoffrey B.; Crowell, Kelly; Girvan, Michelle

    2011-01-01

    Terrestrial vegetation plays a central role in regulating the carbon and water cycles, and adjusting planetary albedo. As such, a clear understanding and accurate characterization of vegetation dynamics is critical to understanding and modeling the broader climate system. Maximum tree height is an important feature of forest vegetation because it is directly related to the overall scale of many ecological and environmental quantities and is an important indicator for understanding several properties of plant communities, including total standing biomass and resource use. We present a model that predicts local maximal tree height across the entire continental United States, in good agreement with data. The model combines scaling laws, which encode the average, base-line behavior of many tree characteristics, with energy budgets constrained by local resource limitations, such as precipitation, temperature and solar radiation. In addition to predicting maximum tree height in an environment, our framework can be extended to predict how other tree traits, such as stomatal density, depend on these resource constraints. Furthermore, it offers predictions for the relationship between height and whole canopy albedo, which is important for understanding the Earth's radiative budget, a critical component of the climate system. Because our model focuses on dominant features, which are represented by a small set of mechanisms, it can be easily integrated into more complicated ecological or climate models. PMID:21695189

  9. Body size and meta-community structure: the allometric scaling of parasitic worm communities in their mammalian hosts.

    PubMed

    DE Leo, Giulio A; Dobson, Andrew P; Gatto, Marino

    2016-06-01

    In this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the 'optimal' size of a parasite species for a host of a given body size; 'optimal' is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population. PMID:27001526

  10. Are tree ontogenetic structure and allometric relationship independent of vegetation formation type? A case study with Cordia oncocalyx in the Brazilian caatinga

    NASA Astrophysics Data System (ADS)

    Silveira, Andréa P.; Martins, Fernando R.; Araújo, Francisca S.

    2012-08-01

    In temperate and tropical rainforests, ontogenetic structure and allometry during tree ontogeny are often associated with light gradients. Light is not considered a limiting resource in deciduous thorny woodland (DTW), but establishment and growth occur during a short rainy period, when the canopy is fully leaved and light in the understory may be modified. Our aim was to investigate whether the light gradient in DTW and the biomechanical limitations of tree growth would be enough to produce an ontogenetic structure and allometric growth similar to rainforest canopy trees. We investigated the ontogenetic stages and diameter-height relationship of Cordia oncocalyx (Boraginaceae), a dominant canopy tree of the DTW of semiarid northeastern Brazil. We tagged, measured and classified the ontogenetic stages of 2.895 individuals in a 1 ha area (5°6'58.1″S and 40°52'19.4″W). In the rainy season only 4.7% of the light falling on the canopy reached the ground. Initial ontogenetic stages, mainly infant (50.9%) and seedling (42.1%), were predominant in the population, with the remaining 7% distributed among juvenile, immature, virginile and reproductive. The ontogenetic structure was similar to that of rainforest tree species, but the population formed both permanent seed and infant banks in response to long dry periods and erratic rainy spells. Like many other Boraginaceae tree species in tropical rainforests, C. oncocalyx has a Prévost architectural model, but allometric growth was quite different from rainforest trees. C. oncocalyx invested slightly more in diameter at first, then in height and finally invested greatly in diameter and attained an asymptotic height. The continued high investment in diameter growth at late stages and the asymptotic height point to low tree density and more frequent xylem embolism as the main drivers of tree allometric shape in DTW. This indicates that tree ontogenetic structure and allometric relationships depend on vegetation

  11. Sexual size and shape dimorphism and allometric scaling patterns in head traits in the New Zealand common gecko Woodworthia maculatus.

    PubMed

    Kelly, Clint D

    2015-08-01

    Sexual dimorphism in shape and size is widespread across animal taxa and arises when natural or sexual selection operates differently on the sexes. Male and female common geckos (Woodworthia maculatus; formerly Hoplodactylus maculatus) in New Zealand do not appear to experience different viability selection pressure, nor do males appear to be under intense pre-copulatory sexual selection. It was therefore predicted that this species would be sexually monomorphic with regard to body size and the size and shape of the head. In line with the prediction, there was no sexual difference in head width, depth, or length or in lateral head shape. However, contrary to prediction, males had a larger body and lateral head size than females. This study suggests that males, at least on Maud Island, NZ, might be under stronger pre-copulatory sexual selection than previously recognized and thus have evolved larger heads (i.e. lateral head size) for use in male combat for females. Allometric scaling patterns do not differ between the sexes and suggest that head width and depth are under directional selection whereas lateral head size is under stabilizing selection. Diet ecology - an agent of natural selection common to both sexes - is likely largely responsible for the observed patterns of head size and shape and the lack of sexual dimorphism in them. PMID:25958103

  12. Allometric scaling of dietary linoleic acid on changes in tissue arachidonic acid using human equivalent diets in mice

    PubMed Central

    2011-01-01

    Background It is hypothesized that dietary linoleic acid (LA) promotes chronic and acute diseases in humans by enriching tissues with arachidonic acid (AA), its downstream metabolite, and dietary studies with rodents have been useful for validation. However, levels of LA in research diets of rodents, as published in the literature, are notoriously erratic making interspecies comparisons unreliable. Therefore, the ability to extrapolate the biological effects of dietary LA from experimental rodents to humans necessitates an allometric scaling model that is rooted within a human equivalent context. Methods To determine the physiological response of dietary LA on tissue AA, a mathematical model for extrapolating nutrients based on energy was used, as opposed to differences in body weight. C57BL/6J mice were divided into 9 groups fed a background diet equivalent to that of the US diet (% energy) with supplemental doses of LA or AA. Changes in the phospholipid fatty acid compositions were monitored in plasma and erythrocytes and compared to data from humans supplemented with equivalent doses of LA or AA. Results Increasing dietary LA had little effect on tissue AA, while supplementing diets with AA significantly increased tissue AA levels, importantly recapitulating results from human trials. Conclusions Thus, interspecies comparisons for dietary LA between rodents and humans can be achieved when rodents are provided human equivalent doses based on differences in metabolic activity as defined by energy consumption. PMID:21702942

  13. The ontogeny of the chin: an analysis of allometric and biomechanical scaling.

    PubMed

    Holton, N E; Bonner, L L; Scott, J E; Marshall, S D; Franciscus, R G; Southard, T E

    2015-06-01

    The presence of a prominent chin in modern humans has been viewed by some researchers as an architectural adaptation to buttress the anterior corpus from bending stresses during mastication. In contrast, ontogenetic studies of mandibular symphyseal form suggest that a prominent chin results from the complex spatial interaction between the symphysis and surrounding soft tissue and skeletal anatomy during development. While variation in chin prominence is clearly influenced by differential growth and spatial constraints, it is unclear to what degree these developmental dynamics influence the mechanical properties of the symphysis. That is, do ontogenetic changes in symphyseal shape result in increased symphyseal bending resistance? We examined ontogenetic changes in the mechanical properties and shape of the symphysis using subjects from a longitudinal cephalometric growth study with ages ranging from 3 to 20+ years. We first examined whether ontogenetic changes in symphyseal shape were correlated with symphyseal vertical bending and wishboning resistance using multivariate regression. Secondly, we examined ontogenetic scaling of bending resistance relative to bending moment arm lengths. An ontogenetic increase in chin prominence was associated with decreased vertical bending resistance, while wishboning resistance was uncorrelated with ontogenetic development of the chin. Relative to bending moment arm lengths, vertical bending resistance scaled with significant negative allometry whereas wishboning resistance scaled isometrically. These results suggest a complex interaction between symphyseal ontogeny and bending resistance, and indicate that ontogenetic increases in chin projection do not provide greater bending resistance to the mandibular symphysis. PMID:25865897

  14. Allometric relationships between seed mass and seedling characteristics reveal trade-offs for neotropical gap-dependent species.

    PubMed

    Daws, Matthew I; Ballard, Christopher; Mullins, Christopher E; Garwood, Nancy C; Murray, Brian; Pearson, Timothy R H; Burslem, David F R P

    2007-12-01

    A seed size-seed number trade-off exists because smaller seeds are produced in greater number but have a lower probability of establishment. This reduced establishment success of smaller-seeded species may be determined by biophysical constraints imposed by scaling rules. Root and shoot diameter, root growth extension rate (RGER) and shoot length at death for dark-grown seedlings are predicted to scale with the cube root of seed embryo and endosperm mass (m). We confirmed this expectation for ten neotropical gap-dependent tree species with an embryo and endosperm dry mass>1 mg. However, for nine smaller seeded species (m<1 mg) with photoblastic germination, root and shoot diameters were larger than expected, and consequently, RGER was slower than expected. The maximum shoot thrust of seedlings from seeds with masses>or=1 mg was comparable to the estimated force required to displace overlying litter, supporting the hypothesis that photoblastic behaviour only occurs in seeds with insufficient shoot thrust to displace overlying leaves. Using the model soil water, energy and transpiration to predict soil drying in small and large gaps, we showed that: (1) gaps that receive a significant amount of direct sunlight will dry more quickly than small gaps that do not, (2) compared to the wet-season, soil that is already dry at depth (i.e. the dry-season) will dry faster after rainfall (this drying would most likely kill seedlings from small seeds) and (3) even during the wet-season, dry periods of a few days in large gaps can kill shallow-rooted seedlings. We conclude that the smaller the seed, the more vulnerable its seedling would be to both covering by litter and soil drying because it can only emerge from shallow depths and has a slow RGER. Consequently, we suggest that these allometrically related factors contribute to the reduced establishment success of smaller-seeded species that underpins the seed size-seed number trade-off. PMID:17846798

  15. Allometric relationships of the dentition of the great White Shark, Carcharodon carcharias, in forensic investigations of shark attacks.

    PubMed

    Nambiar, P; Bridges, T E; Brown, K A

    1991-06-01

    As a result of a systematic morphometric study of shark dentitions, a system of notation for describing the location of shark teeth has been developed and is proposed as a standard to be adopted for use in similar studies in the future. The macroscopic morphology of White Shark teeth has been characterised in order to gain quantitative data which might assist in identification of these sharks from bite marks on victims or objects or from shark carcasses. Using these data, a nomogram has been developed which can be used to estimate the body length of a White Shark from measurements of tooth or bite mark morphology. An example of the forensic application of such allometric data is provided as it applied to a recent fatal attack on a diver by a White Shark. PMID:1814935

  16. Long-term food consumption and body weight changes in neotame safety studies are consistent with the allometric relationship observed for other sweeteners and during dietary restrictions.

    PubMed

    Flamm, W Gary; Blackburn, George L; Comer, C Phil; Mayhew, Dale A; Stargel, W Wayne

    2003-10-01

    In long-term safety studies with neotame, a new high-intensity sweetener 7000-13,000 times sweeter than sucrose, the percent changes (%Delta) in body weight gain (BWG) in Sprague-Dawley rats were several-fold greater than the %Delta in overall food consumption (FC). This study investigates the question of whether the changes in BWG were adverse or secondary to small, long-term decrements in FC. The hypothesis tested in Sprague-Dawley rats was that the relationship between long-term %Delta in FC and %Delta in BWG is linear and in a ratio of 1:1. The %Delta in FC were compared to %Delta in BWG after 52 weeks on study in one saccharin (825 rats), two sucralose (480 rats), two neotame (630 rats), and five dietary restriction (>1000 rats) studies. Non-transformed plotting of data points demonstrated an absence of linearity between %Delta in FC and %Delta in BWG; however, log-log evaluation demonstrated a robust (R2=0.97) linear relationship between %Delta in FC and %Delta in BWG. This relationship followed the well-known allometric equation, y=bxa where x is %DeltaFC, y is %DeltaBWG, b is %DeltaBWG when DeltaFC=1, and a is the log-log slope. Thus, in Sprague-Dawley rats at week 52, the long-term relationship between %Delta in FC and %Delta in BWG was determined to be: %DeltaBWG=3.45(%DeltaFC0.74) for males and %DeltaBWG=5.28(%DeltaFC0.68) for females. Sexes were statistically different but study types, i.e., the high-intensity sweeteners saccharin and sucralose versus dietary restriction, were not. The %Delta in BWG are allometrically consistent with the observed %Delta in FC for these high-intensity sweeteners, including neotame. BW parameters are not appropriate endpoints for setting no-observed-effect levels (NOELs) when materials with intense taste are admixed into food. An approach using objective criteria is proposed to delineate BW changes due to toxicity from those secondary to reduced FC. PMID:14550756

  17. A kinetic-allometric approach to predicting tissue radionuclide concentrations for biota.

    PubMed

    Higley, K A; Domotor, S L; Antonio, E J

    2003-01-01

    Allometry, or the biology of scaling, is the study of size and its consequences. It has become a useful tool for comparative physiology. There are several allometric equations that relate body size to many parameters, including ingestion rate, lifespan, inhalation rate, home range and more. While these equations were originally derived from empirical observations, there is a growing body of evidence that these relationships have their origins in the dynamics of energy transport mechanisms. As part of an ongoing effort by the Department of Energy in developing generic methods for evaluating radiation dose to biota, we have examined the utility of applying allometric techniques to predicting radionuclide tissue concentration across a large range of terrestrial and riparian species of animals. This particular study examined 23 radionuclides. Initial investigations suggest that the allometric approach can provide a useful tool to derive limiting values of uptake and elimination factors for animals. PMID:12590070

  18. Growth of the eye lens: II. Allometric studies

    PubMed Central

    2014-01-01

    Purpose The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Methods Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated from wet and dry weights with eye volumes calculated from axial length. Results Linear allometric relationships were obtained for the comparison of ontogenic lens and bodyweight accumulation. The body mass exponent (BME) decreased with increasing animal size from around 1.0 in small rodents to 0.4 in large ungulates for both wet and dry weights. Compaction constants for the ontogenic growth ranged from 1.00 in birds and reptiles up to 1.30 in mammals. Allometric comparison of maximum lens wet and dry weights with maximum bodyweights also yielded linear plots with a BME of 0.504 for all warm blooded species except primates which had a BME of 0.25. When lens volumes were compared with eye volumes, all species yielded a scaling constant of 0.75 but the proportionality constants for primates and birds were lower. Conclusions Ontogenic lens growth is fastest, relative to body growth, in small animals and slowest in large animals. Fiber cell compaction takes place throughout life in most species, but not in birds and reptiles. Maximum adult lens size scales with eye size with the same exponent in all species, but birds and primates have smaller lenses relative to eye size than other species. Optical properties of the lens are generated through the combination of variations in the rate of growth, rate of compaction, shape and size. PMID:24715759

  19. Allometric Scaling of Patrolling Rate and Nest Volume in Constrictotermes cyphergaster Termites: Hints on the Settlement of Inquilines

    PubMed Central

    DeSouza, Og; Araújo, Ana Paula Albano; Florencio, Daniela Faria; Rosa, Cassiano Sousa; Marins, Alessandra; Costa, Diogo Andrade; Rodrigues, Vinicius Barros; Cristaldo, Paulo Fellipe

    2016-01-01

    Structural and functional traits of organisms are known to be related to the size of individuals and to the size of their colonies when they belong to one. Among such traits, propensity to inquilinism in termites is known to relate positively to colony size. Larger termitaria hold larger diversity of facultative inquilines than smaller nests, whereas obligate inquilines seem unable to settle in nests smaller than a threshold volume. Respective underlying mechanisms, however, remain hypothetical. Here we test one of such hypotheses, namely, that nest defence correlates negatively to nest volume in Constrictotermes cyphergaster termites (Termitidae: Nasutitermitinae). As a surrogate to defence, we used ‘patrolling rate’, i.e., the number of termite individuals attending per unit time an experimentally damaged spot on the outer wall of their termitaria. We found that patrolling rate decayed allometrically with increasing nest size. Conspicuously higher patrolling rates occurred in smaller nests, while conspicuously lower rates occurred in larger nests presenting volumes in the vicinity of the threshold value for the establishment of inquilinism. This could be proven adaptive for the host and guest. At younger nest age, host colonies are smaller and presumably more vulnerable and unstable. Enhanced defence rates may, hence, prevent eventual risks to hosts from inquilinism at the same time that it prevents inquilines to settle in a still unstable nest. Conversely, when colonies grow and maturate enough to stand threats, they would invest in priorities other than active defence, opening an opportunity for inquilines to settle in nests which are more suitable or less risky. Under this two-fold process, cohabitation between host and inquiline could readily stabilize. PMID:26808197

  20. Allometric Scaling of Patrolling Rate and Nest Volume in Constrictotermes cyphergaster Termites: Hints on the Settlement of Inquilines.

    PubMed

    DeSouza, Og; Araújo, Ana Paula Albano; Florencio, Daniela Faria; Rosa, Cassiano Sousa; Marins, Alessandra; Costa, Diogo Andrade; Rodrigues, Vinicius Barros; Cristaldo, Paulo Fellipe

    2016-01-01

    Structural and functional traits of organisms are known to be related to the size of individuals and to the size of their colonies when they belong to one. Among such traits, propensity to inquilinism in termites is known to relate positively to colony size. Larger termitaria hold larger diversity of facultative inquilines than smaller nests, whereas obligate inquilines seem unable to settle in nests smaller than a threshold volume. Respective underlying mechanisms, however, remain hypothetical. Here we test one of such hypotheses, namely, that nest defence correlates negatively to nest volume in Constrictotermes cyphergaster termites (Termitidae: Nasutitermitinae). As a surrogate to defence, we used 'patrolling rate', i.e., the number of termite individuals attending per unit time an experimentally damaged spot on the outer wall of their termitaria. We found that patrolling rate decayed allometrically with increasing nest size. Conspicuously higher patrolling rates occurred in smaller nests, while conspicuously lower rates occurred in larger nests presenting volumes in the vicinity of the threshold value for the establishment of inquilinism. This could be proven adaptive for the host and guest. At younger nest age, host colonies are smaller and presumably more vulnerable and unstable. Enhanced defence rates may, hence, prevent eventual risks to hosts from inquilinism at the same time that it prevents inquilines to settle in a still unstable nest. Conversely, when colonies grow and maturate enough to stand threats, they would invest in priorities other than active defence, opening an opportunity for inquilines to settle in nests which are more suitable or less risky. Under this two-fold process, cohabitation between host and inquiline could readily stabilize. PMID:26808197

  1. The allometric relationship between resting metabolic rate and body mass in wild waterfowl (Anatidae) and an application to estimation of winter habitat requirements

    USGS Publications Warehouse

    Miller, M.R.; Eadie, J. McA

    2006-01-01

    We examined the allometric relationship between resting metabolic rate (RMR; kJ day-1) and body mass (kg) in wild waterfowl (Anatidae) by regressing RMR on body mass using species means from data obtained from published literature (18 sources, 54 measurements, 24 species; all data from captive birds). There was no significant difference among measurements from the rest (night; n = 37), active (day; n = 14), and unspecified (n = 3) phases of the daily cycle (P > 0.10), and we pooled these measurements for analysis. The resulting power function (aMassb) for all waterfowl (swans, geese, and ducks) had an exponent (b; slope of the regression) of 0.74, indistinguishable from that determined with commonly used general equations for nonpasserine birds (0.72-0.73). In contrast, the mass proportionality coefficient (b; y-intercept at mass = 1 kg) of 422 exceeded that obtained from the nonpasserine equations by 29%-37%. Analyses using independent contrasts correcting for phylogeny did not substantially alter the equation. Our results suggest the waterfowl equation provides a more appropriate estimate of RMR for bioenergetics analyses of waterfowl than do the general nonpasserine equations. When adjusted with a multiple to account for energy costs of free living, the waterfowl equation better estimates daily energy expenditure. Using this equation, we estimated that the extent of wetland habitat required to support wintering waterfowl populations could be 37%-50% higher than previously predicted using general nonpasserine equations. ?? The Cooper Ornithological Society 2006.

  2. Developing a generalized allometric equation for aboveground biomass estimation

    NASA Astrophysics Data System (ADS)

    Xu, Q.; Balamuta, J. J.; Greenberg, J. A.; Li, B.; Man, A.; Xu, Z.

    2015-12-01

    A key potential uncertainty in estimating carbon stocks across multiple scales stems from the use of empirically calibrated allometric equations, which estimate aboveground biomass (AGB) from plant characteristics such as diameter at breast height (DBH) and/or height (H). The equations themselves contain significant and, at times, poorly characterized errors. Species-specific equations may be missing. Plant responses to their local biophysical environment may lead to spatially varying allometric relationships. The structural predictor may be difficult or impossible to measure accurately, particularly when derived from remote sensing data. All of these issues may lead to significant and spatially varying uncertainties in the estimation of AGB that are unexplored in the literature. We sought to quantify the errors in predicting AGB at the tree and plot level for vegetation plots in California. To accomplish this, we derived a generalized allometric equation (GAE) which we used to model the AGB on a full set of tree information such as DBH, H, taxonomy, and biophysical environment. The GAE was derived using published allometric equations in the GlobAllomeTree database. The equations were sparse in details about the error since authors provide the coefficient of determination (R2) and the sample size. A more realistic simulation of tree AGB should also contain the noise that was not captured by the allometric equation. We derived an empirically corrected variance estimate for the amount of noise to represent the errors in the real biomass. Also, we accounted for the hierarchical relationship between different species by treating each taxonomic level as a covariate nested within a higher taxonomic level (e.g. species < genus). This approach provides estimation under incomplete tree information (e.g. missing species) or blurred information (e.g. conjecture of species), plus the biophysical environment. The GAE allowed us to quantify contribution of each different

  3. Allometric biomass partitioning under nitrogen enrichment: Evidence from manipulative experiments around the world

    PubMed Central

    Peng, Yunfeng; Yang, Yuanhe

    2016-01-01

    Allometric and optimal hypotheses have been widely used to explain biomass partitioning in response to resource changes for individual plants; however, little evidence has been reported from measurements at the community level across a broad geographic scale. This study assessed the nitrogen (N) effect on community-level root to shoot (R/S) ratios and biomass partitioning functions by synthesizing global manipulative experiments. Results showed that, in aggregate, N addition decreased the R/S ratios in various biomes. However, the scaling slopes of the allometric equations were not significantly altered by the N enrichment, possibly indicating that N-induced reduction of the R/S ratio is a consequence of allometric allocation as a function of increasing plant size rather than an optimal partitioning model. To further illustrate this point, we developed power function models to explore the relationships between aboveground and belowground biomass for various biomes; then, we generated the predicted root biomass from the observed shoot biomass and predicted R/S ratios. The comparison of predicted and observed N-induced changes of the R/S ratio revealed no significant differences between each other, supporting the allometric allocation hypothesis. These results suggest that allometry, rather than optimal allocation, explains the N-induced reduction in the R/S ratio across global biomes. PMID:27349584

  4. Allometric biomass partitioning under nitrogen enrichment: Evidence from manipulative experiments around the world.

    PubMed

    Peng, Yunfeng; Yang, Yuanhe

    2016-01-01

    Allometric and optimal hypotheses have been widely used to explain biomass partitioning in response to resource changes for individual plants; however, little evidence has been reported from measurements at the community level across a broad geographic scale. This study assessed the nitrogen (N) effect on community-level root to shoot (R/S) ratios and biomass partitioning functions by synthesizing global manipulative experiments. Results showed that, in aggregate, N addition decreased the R/S ratios in various biomes. However, the scaling slopes of the allometric equations were not significantly altered by the N enrichment, possibly indicating that N-induced reduction of the R/S ratio is a consequence of allometric allocation as a function of increasing plant size rather than an optimal partitioning model. To further illustrate this point, we developed power function models to explore the relationships between aboveground and belowground biomass for various biomes; then, we generated the predicted root biomass from the observed shoot biomass and predicted R/S ratios. The comparison of predicted and observed N-induced changes of the R/S ratio revealed no significant differences between each other, supporting the allometric allocation hypothesis. These results suggest that allometry, rather than optimal allocation, explains the N-induced reduction in the R/S ratio across global biomes. PMID:27349584

  5. Allometric biomass partitioning under nitrogen enrichment: Evidence from manipulative experiments around the world

    NASA Astrophysics Data System (ADS)

    Peng, Yunfeng; Yang, Yuanhe

    2016-06-01

    Allometric and optimal hypotheses have been widely used to explain biomass partitioning in response to resource changes for individual plants; however, little evidence has been reported from measurements at the community level across a broad geographic scale. This study assessed the nitrogen (N) effect on community-level root to shoot (R/S) ratios and biomass partitioning functions by synthesizing global manipulative experiments. Results showed that, in aggregate, N addition decreased the R/S ratios in various biomes. However, the scaling slopes of the allometric equations were not significantly altered by the N enrichment, possibly indicating that N-induced reduction of the R/S ratio is a consequence of allometric allocation as a function of increasing plant size rather than an optimal partitioning model. To further illustrate this point, we developed power function models to explore the relationships between aboveground and belowground biomass for various biomes; then, we generated the predicted root biomass from the observed shoot biomass and predicted R/S ratios. The comparison of predicted and observed N-induced changes of the R/S ratio revealed no significant differences between each other, supporting the allometric allocation hypothesis. These results suggest that allometry, rather than optimal allocation, explains the N-induced reduction in the R/S ratio across global biomes.

  6. Preclinical Efficacy and Safety Profile of Allometrically Scaled Doses of Doxycycline Used to Turn "On" Therapeutic Transgene Expression from High-Capacity Adenoviral Vectors in a Glioma Model.

    PubMed

    VanderVeen, Nathan; Raja, Nicholas; Yi, Elizabeth; Appelman, Henry; Ng, Philip; Palmer, Donna; Zamler, Daniel; Dzaman, Marta; Lowenstein, Pedro R; Castro, Maria G

    2016-06-01

    Glioblastoma multiforme (GBM) is the most commonly occurring primary brain cancer in adults, in whom its highly infiltrative cells prevent total surgical resection, often leading to tumor recurrence and patient death. Our group has discovered a gene therapy approach for GBM that utilizes high-capacity "gutless" adenoviral vectors encoding regulatable therapeutic transgenes. The herpes simplex type 1-thymidine kinase (TK) actively kills dividing tumor cells in the brain when in the presence of the prodrug, ganciclovir (GCV), whereas the FMS-like tyrosine kinase 3 ligand (Flt3L) is an immune-stimulatory molecule under tight regulation by a tetracycline-inducible "Tet-On" activation system that induces anti-GBM immunity. As a prelude to a phase I clinical trial, we evaluated the safety and efficacy of Food and Drug Administration (FDA)-approved doses of the tetracycline doxycycline (DOX) allometrically scaled for rats. DOX initiates the expression of Flt3L, which has been shown to recruit dendritic cells to the brain tumor microenvironment-an integral first step in the development of antitumor immunity. The data revealed a highly safe profile surrounding these human-equivalent doses of DOX under an identical therapeutic window as proposed in the clinical trial. This was confirmed through a neuropathological analysis, liver and kidney histopathology, detection of neutralizing antibodies, and systemic toxicities in the blood. Interestingly, we observed a significant survival advantage in rats with GBM receiving the 300 mg/day equivalent dosage of DOX versus the 200 mg/day equivalent. Additionally, rats rejected "recurrent" brain tumor threats implanted 90 days after their primary brain tumors. We also show that DOX detection within the plasma can be an indicator of optimal dosing of DOX to attain therapeutic levels. This work has significant clinical relevance for an ongoing phase I clinical trial in humans with primary GBM and for other therapeutic approaches using

  7. Small Sample Sizes Yield Biased Allometric Equations in Temperate Forests.

    PubMed

    Duncanson, L; Rourke, O; Dubayah, R

    2015-01-01

    Accurate quantification of forest carbon stocks is required for constraining the global carbon cycle and its impacts on climate. The accuracies of forest biomass maps are inherently dependent on the accuracy of the field biomass estimates used to calibrate models, which are generated with allometric equations. Here, we provide a quantitative assessment of the sensitivity of allometric parameters to sample size in temperate forests, focusing on the allometric relationship between tree height and crown radius. We use LiDAR remote sensing to isolate between 10,000 to more than 1,000,000 tree height and crown radius measurements per site in six U.S. forests. We find that fitted allometric parameters are highly sensitive to sample size, producing systematic overestimates of height. We extend our analysis to biomass through the application of empirical relationships from the literature, and show that given the small sample sizes used in common allometric equations for biomass, the average site-level biomass bias is ~+70% with a standard deviation of 71%, ranging from -4% to +193%. These findings underscore the importance of increasing the sample sizes used for allometric equation generation. PMID:26598233

  8. Small Sample Sizes Yield Biased Allometric Equations in Temperate Forests

    PubMed Central

    Duncanson, L.; Rourke, O.; Dubayah, R.

    2015-01-01

    Accurate quantification of forest carbon stocks is required for constraining the global carbon cycle and its impacts on climate. The accuracies of forest biomass maps are inherently dependent on the accuracy of the field biomass estimates used to calibrate models, which are generated with allometric equations. Here, we provide a quantitative assessment of the sensitivity of allometric parameters to sample size in temperate forests, focusing on the allometric relationship between tree height and crown radius. We use LiDAR remote sensing to isolate between 10,000 to more than 1,000,000 tree height and crown radius measurements per site in six U.S. forests. We find that fitted allometric parameters are highly sensitive to sample size, producing systematic overestimates of height. We extend our analysis to biomass through the application of empirical relationships from the literature, and show that given the small sample sizes used in common allometric equations for biomass, the average site-level biomass bias is ~+70% with a standard deviation of 71%, ranging from −4% to +193%. These findings underscore the importance of increasing the sample sizes used for allometric equation generation. PMID:26598233

  9. Allometric control of human gait

    NASA Astrophysics Data System (ADS)

    Griffin, Lori Ann

    The purpose of the study was to extract the information contained in the fluctuations in the stride interval time series and the correlation properties of walking. To determine if the time series had memory or long-time correlation properties, the decay (loss) of correlation of the data across time was studied. The information acquired was to determine if control of walking could be better understood, by studying statistics of stride intervals. Furthermore, it was determined if the time series for walking was stable enough to establish a baseline for future studies. Allometric analysis was done on relaxed walking for 10 individuals. The data obtained during the experiments consisted of the time interval for a given stride and the number of strides in the sequence of steps. The maximal extension of the right leg, the ``stride interval'' versus the stride number, yielded a graph that has all the characteristics of a time series. Insight into the stride interval time series was obtained using relative dispersion, also know as the coefficient of variation, the ratio of the standard deviation to the mean. The results indicated memory in the control of walking for all subjects. Furthermore, memory was not maintained once the data was randomized suggesting the order of strides is important. The amount of memory differed for each subject, whereby some subjects had significant memory (high correlation coefficients = 0.693) while others showed low correlation coefficients. The relative dispersion for all subjects decreased with increasing aggregation number. This straight line with a negative slope depicted an inverse power-law relation between the relative dispersion and the aggregation number. The data does not have a dominant scale and can be evaluated on many scales without information lost. Although these data alone do not establish a baseline, the data analyzed using allometric analysis appears sufficiently stable to establish a baseline norm for walking. Finally, the

  10. Prediction of a potentially effective dose in humans for BAY 60–5521, a potent inhibitor of cholesteryl ester transfer protein (CETP) by allometric species scaling and combined pharmacodynamic and physiologically-based pharmacokinetic modelling

    PubMed Central

    Weber, Olaf; Willmann, Stefan; Bischoff, Hilmar; Li, Volkhart; Vakalopoulos, Alexandros; Lustig, Klemens; Hafner, Frank-Thorsten; Heinig, Roland; Schmeck, Carsten; Buehner, Klaus

    2012-01-01

    AIMS The purpose of this work was to support the prediction of a potentially effective dose for the CETP-inhibitor, BAY 60–5521, in humans. METHODS A combination of allometric scaling of the pharmacokinetics of the CETP-inhibitor BAY 60–5521 with pharmacodynamic studies in CETP-transgenic mice and in human plasma with physiologically-based pharmacokinetic (PBPK) modelling was used to support the selection of the first-in-man dose. RESULTS The PBPK approach predicts a greater extent of distribution for BAY 60–5521 in humans compared with the allometric scaling method as reflected by a larger predicted volume of distribution and longer elimination half-life. The combined approach led to an estimate of a potentially effective dose for BAY 60–5521 of 51 mg in humans. CONCLUSION The approach described in this paper supported the prediction of a potentially effective dose for the CETP-inhibitor BAY 60–5521 in humans. Confirmation of the dose estimate was obtained in a first-in-man study. PMID:21762205

  11. An Allometric Analysis of Sex and Sex Chromosome Dosage Effects on Subcortical Anatomy in Humans.

    PubMed

    Reardon, Paul Kirkpatrick; Clasen, Liv; Giedd, Jay N; Blumenthal, Jonathan; Lerch, Jason P; Chakravarty, M Mallar; Raznahan, Armin

    2016-02-24

    Structural neuroimaging of humans with typical and atypical sex-chromosome complements has established the marked influence of both Yand X-/Y-chromosome dosage on total brain volume (TBV) and identified potential cortical substrates for the psychiatric phenotypes associated with sex-chromosome aneuploidy (SCA). Here, in a cohort of 354 humans with varying karyotypes (XX, XY, XXX, XXY, XYY, XXYY, XXXXY), we investigate sex and SCA effects on subcortical size and shape; focusing on the striatum, pallidum and thalamus. We find large effect-size differences in the volume and shape of all three structures as a function of sex and SCA. We correct for TBV effects with a novel allometric method harnessing normative scaling rules for subcortical size and shape in humans, which we derive here for the first time. We show that all three subcortical volumes scale sublinearly with TBV among healthy humans, mirroring known relationships between subcortical volume and TBV among species. Traditional TBV correction methods assume linear scaling and can therefore invert or exaggerate sex and SCA effects on subcortical anatomy. Allometric analysis restricts sex-differences to: (1) greater pallidal volume (PV) in males, and (2) relative caudate head expansion and ventral striatum contraction in females. Allometric analysis of SCA reveals that supernumerary X- and Y-chromosomes both cause disproportionate reductions in PV, and coordinated deformations of striatopallidal shape. Our study provides a novel understanding of sex and sex-chromosome dosage effects on subcortical organization, using an allometric approach that can be generalized to other basic and clinical structural neuroimaging settings. PMID:26911691

  12. Simplified gyral pattern in severe developmental microcephalies? New insights from allometric modeling for spatial and spectral analysis of gyrification.

    PubMed

    Germanaud, D; Lefèvre, J; Fischer, C; Bintner, M; Curie, A; des Portes, V; Eliez, S; Elmaleh-Bergès, M; Lamblin, D; Passemard, S; Operto, G; Schaer, M; Verloes, A; Toro, R; Mangin, J F; Hertz-Pannier, L

    2014-11-15

    The strong positive-allometric relationship between brain size, cortical extension and gyrification complexity, recently highlighted in the general population, could be modified by brain developmental disorders. Indeed, in case of brain growth insufficiency, the pathophysiological relevance of the "simplified gyral pattern" phenotype is strongly disputed since almost no genotype-phenotype correlations have been found in primary microcephalies. Using surface scaling analysis and newly-developed spectral analysis of gyrification (Spangy), we tested whether the gyral simplification in groups of severe microcephalies related to ASPM, PQBP1 or fetal-alcohol-syndrome could be fully explained by brain size reduction according to the allometric scaling law established in typically-developing control groups, or whether an additional disease effect was to be suspected. We found the surface area reductions to be fully explained by scaling effect, leading to predictable folding intensities measured by gyrification indices. As for folding pattern assessed by spectral analysis, scaling effect also accounted for the majority of the variations, but an additional negative or positive disease effect was found in the case of ASPM and PQBP1-linked microcephalies, respectively. Our results point out the necessity of taking allometric scaling into account when studying the gyrification variability in pathological conditions. They also show that the quantitative analysis of gyrification complexity through spectral analysis can enable distinguishing between even (predictable, non-specific) and uneven (unpredictable, maybe disease-specific) gyral simplifications. PMID:25107856

  13. Interspecies allometric analysis of the comparative pharmacokinetics of 44 drugs across veterinary and laboratory animal species.

    PubMed

    Riviere, J E; Martin-Jimenez, T; Sundlof, S F; Craigmill, A L

    1997-12-01

    The purpose of this study was to apply the method of allometric analysis to a study of the comparative disposition of veterinary drugs using the Food Animal Residue Avoidance Databank (FARAD) as a source of the comparative pharmacokinetic data. An initial filtration of the FARAD data was performed in order to exclude drugs for which no pharmacokinetic data were available, in at least four species the route of administration was other than intravenous, and the matrix was different from blood, plasma or serum. This process restricted the study to a total of 44 candidate drugs. The primary pharmacokinetic parameter selected for study was half-life (t1/2). As this parameter is a composite of clearance (Cl) and volume of distribution (Vd), it was considered to be the most robust for interspecies scaling. Volume of distribution at steady state (Vdss) and clearance showed weak allometric correlations with weight across species. The relationships between body weight and elimination half-life (51/2 beta) were determined for this selected group of drugs by using the empirically determined function Y = a Wb. The function Y represents the parameter of concern (half-life), a is a coefficient typical of every drug (intercept), W is the species average body weight, and b is the scaling exponent. A total of 11 drugs (tetracycline, oxytetracycline, chlortetracycline, erythromycin, diazepam, prednisolone, cephapirin, ampicillin, gentamicin, apramycin and carbenicillin) showed statistically significant correlations and consequently are excellent candidates for interspecies extrapolation of pharmacokinetic parameters (half-life) in species of relevance to veterinary medicine. The remaining 33 drugs were divided into two groups which showed various degrees of lack of correlation. Many of the drugs that showed no allometric correlation were low hepatic extraction drugs. However, some other drugs demonstrated equivocal results which could either be due to a true lack of allometric

  14. Multidimensional Scaling Applied to Linguistic Relationships.

    ERIC Educational Resources Information Center

    Black, Paul

    1973-01-01

    As the several specific applications in this paper demonstrate, multidimensional scaling provides a long-needed means for investigating and describing spatial relationships among speech varieties. It is especially applicable to the relationships among varieties of a single language (or more properly, linguistic "cline"), which, as is generally…

  15. The relationship between canopy structure, light dynamics and deciduousness in a seasonal tropical forest in Panama: A multiple scale study using remote sensing and allometry

    NASA Astrophysics Data System (ADS)

    Bohlman, Stephanie Ann

    This dissertation uses two tools, remote sensing and allometry, to quantify canopy structure, phenology and light interception on stand to landscape levels in a semi-deciduous tropical forest in Panama. The remote sensing studies used a multiple scale approach. First relationships between spectral and physiological data were developed on a fine spatial scale. Then the interpretations were verified at a series of plots across the landscape. Finally, interpretation was applied to satellite images of the whole Panama Canal Zone. Using this approach, the applicability of the relationship between the Normalized Difference Vegetation Index (NDVI) and fraction of intercepted photosynthetically active radiation (FPAR) was tested for the first time in a tropical forest. NDVI was more strongly related to changes in the FPAR of the upper canopy than FPAR of the whole canopy profile. Both NDVI and FPAR were driven by the contrast of deciduous and non-deciduous tree crowns in the dry season. On a landscape scale, spectral mixture analysis (SMA) of remotely-sensed images quantified the percent of deciduous tree crowns in the overstory very accurately. Using the map of deciduousness developed from a Landsat image, I found high fine scale variability in deciduousness, highly deciduous patches throughout the canal zone of 4--250 ha in size, and landscape trends related to rainfall and geologic formation. Allometric relationships between stem diameter, tree height and crown size were developed for 65 species on Barro Colorado Island. Tree height was asymptotic with stem diameter, but crown radius was not, continuing to grow at large diameters. Allometric relationships through ontongeny varied among different functional groups. Gap species are taller than shade species when both functional groups were below 10 cm dbh, but have smaller crowns than shade species above 10 cm dbh. Subcanopy species are shorter with larger canopies than tall species. A simple canopy model based on these

  16. Development of the Dyadic Relationship Scale

    ERIC Educational Resources Information Center

    Haskan Avci, Özlem

    2014-01-01

    Problem Statement: The rise of premarital studies raises questions about the effectiveness of educational programs developed to prepare young couples for marriage and family life. Purpose of Study: The purpose of this study is to describe and introduce the Dyadic Relationship Scale (DRS) for use with university students. The author developed the…

  17. Scaling Relationships for Spherical Polymer Brushes Revisited.

    PubMed

    Chen, Guang; Li, Hao; Das, Siddhartha

    2016-06-16

    In this short paper, we revisit the scaling relationships for spherical polymer brushes (SPBs), i.e., polymer brushes grafted to rigid, spherical particles. Considering that the brushes can be described to be encased in a series of hypothetical spherical blobs, we identify significant physical discrepancies in the model of Daoud and Cotton (Journal of Physics, 1982), which is considered to be the state of the art in scaling modeling of SPBs. We establish that the "brush" configuration of the polymer molecules forming the SPBs is possible only if the swelling ratio (which is the ratio of the end-to-end length of the blob-encased polymer segment to the corresponding coil-like polymer segment) is always less than unity-a notion that has been erroneously overlooked in the model of Daoud and Cotton. We also provide new scaling arguments that (a) establish this swelling (or more appropriately shrinking) ratio as a constant (less than unity) for the case of "good" solvent, (b) recover the scaling predictions for blob dimension and monomer number and monomer concentration distributions within the blob, and PMID:27232497

  18. Allometric and metameric shape variation in Pan mandibular molars: a digital morphometric analysis.

    PubMed

    Singleton, Michelle; Rosenberger, Alfred L; Robinson, Chris; O'neill, Rob

    2011-02-01

    The predominance of molar teeth in fossil hominin assemblages makes the patterning of molar shape variation a topic of bioanthropological interest. Extant models are the principal basis for understanding dental variation in the fossil record. As the sister taxon to the hominin clade, Pan is one such model and the only widely accepted extant hominid model for both interspecific and intraspecific variation. To explore the contributions of allometric scaling and meristic variation to molar variation in Pan, we applied geometric shape analysis to 3D landmarks collected from virtual replicas of chimpanzee and bonobo mandibular molars. Multivariate statistical analysis and 3D visualization of metameric and allometric shape vectors were used to characterize shape differences and test the hypothesis that species of Pan share patterns of metameric variation and molar shape allometry. Procrustes-based shape variables were found to effectively characterize crown shape, sorting molars into species and tooth-row positions with ≥ 95% accuracy. Chimpanzees and bonobos share a common pattern of M(1) -M(2) metameric variation, which is defined by differences in the relative position of the metaconid, size of the hypoconulid, curvature of the buccal wall, and proportions of the basins and foveae. Allometric scaling of molar shape is homogeneous for M(1) and M(2) within species, but bonobo and chimpanzee allometric vectors are significantly different. Nevertheless, the common allometric shape trend explains most molar-shape differences between P. paniscus and P. troglodytes. When allometric effects are factored out, chimpanzee and bonobo molars are not morphometrically distinguishable. Implications for hominid taxonomy and dietary reconstruction are discussed. PMID:21235007

  19. Julian Huxley, Uca pugnax and the allometric method.

    PubMed

    Packard, Gary C

    2012-02-15

    The allometric method, which often is attributed to Julian Huxley, entails fitting a straight line to logarithmic transformations of the original bivariate data and then back-transforming the resulting equation to form a power function in the arithmetic scale. Development of the technique was strongly influenced by Huxley's own research on growth by the enlarged 'crusher' claw in male fiddler crabs (Uca pugnax). Huxley reported a discontinuity in the log-log plot of chela mass vs body mass, which he interpreted as an abrupt change in relative growth of the chela at about the time crabs attain sexual maturity. My analysis of Huxley's arithmetic data indicates, however, that the discontinuity was an artifact caused by logarithmic transformation and that dynamics of growth by the crusher claw do not change at any point during development. Arithmetic data are well described by a power function fitted by nonlinear regression but not by one estimated by back-transforming a line fitted to logarithms. This finding and others like it call into question the continued reliance on the allometric method in contemporary research. PMID:22279062

  20. Invariant relationships deriving from classical scaling transformations

    SciTech Connect

    Bludman, Sidney; Kennedy, Dallas C.

    2011-04-15

    Because scaling symmetries of the Euler-Lagrange equations are generally not variational symmetries of the action, they do not lead to conservation laws. Instead, an extension of Noether's theorem reduces the equations of motion to evolutionary laws that prove useful, even if the transformations are not symmetries of the equations of motion. In the case of scaling, symmetry leads to a scaling evolutionary law, a first-order equation in terms of scale invariants, linearly relating kinematic and dynamic degrees of freedom. This scaling evolutionary law appears in dynamical and in static systems. Applied to dynamical central-force systems, the scaling evolutionary equation leads to generalized virial laws, which linearly connect the kinetic and potential energies. Applied to barotropic hydrostatic spheres, the scaling evolutionary equation linearly connects the gravitational and internal energy densities. This implies well-known properties of polytropes, describing degenerate stars and chemically homogeneous nondegenerate stellar cores.

  1. An allometric analysis of the number of muscle spindles in mammalian skeletal muscles.

    PubMed

    Banks, R W

    2006-06-01

    An allometric analysis of the number of muscle spindles in relation to muscle mass in mammalian (mouse, rat, guinea-pig, cat, human) skeletal muscles is presented. It is shown that the trend to increasing number as muscle mass increases follows an isometric (length) relationship between species, whereas within a species, at least for the only essentially complete sample (human), the number of spindles scales, on average, with the square root rather than the cube root of muscle mass. An attempt is made to reconcile these apparently discrepant relationships. Use of the widely accepted spindle density (number of spindles g(-1) of muscle) as a measure of relative abundance of spindles in different muscles is shown to be grossly misleading. It is replaced with the residuals of the linear regression of ln spindle number against ln muscle mass. Significant differences in relative spindle abundance as measured by residuals were found between regional groups of muscles: the greatest abundance is in axial muscles, including those concerned with head position, whereas the least is in muscles of the shoulder girdle. No differences were found between large and small muscles operating in parallel, or between antigravity and non-antigravity muscles. For proximal vs. distal muscles, spindles were significantly less abundant in the hand than the arm, but there was no difference between the foot and the leg. PMID:16761976

  2. Morphological changes and allometric growth in hatchery-reared Chinese loach Paramisgurnus dabryanus (Dabry de Thiersant, 1872)

    NASA Astrophysics Data System (ADS)

    Zhang, Yunlong; Wu, Qiaowan; Hu, Weihua; Wang, Fan; Shao, Weihan; Zhang, Chengming; Zhao, Zhongbo; He, Hui; Fan, Qixue; Gu, Zemao

    2016-07-01

    The length-weight relationship and allometric growth patterns of hatchery-reared Chinese loach, Paramisgurnus dabryanus (Dabry de Thiersant, 1872), were determined from hatching to 60 days after hatching. A best power model was estimated for the length-weight relationship during the early life stages. Positive allometric growth for the head segment, trunk length, tail length and eye diameter was also found in the early life stages, while body depth, tail depth, tail fin length, pectoral fin length and barbel length displayed a negative coefficient. During the subsequent early developmental stage, the growth coefficients showed a clear and common tendency towards isometry for all measured body ratios. The allometric growth changes in Chinese loach during the early stage are possibly the result of selective organogenesis directed towards survival priorities.

  3. [Spatial distribution pattern and allometric growth of three common species on moving sand dunes in Horqin Sandy Land, China].

    PubMed

    Jia, Mei-yu; Li, Xue-hua; Oh, Choong-hyeon; Park, Hong-chul; Miao, Chun-ping; Han, Xu

    2015-10-01

    Research on fine scale pattern and characteristics of allometric growth could contribute to better understanding plants' adaptation in moving sandy dunes. The abundance, height and biomass of 3 species Agriophilum aquarrosum, Corispermum candelabrum and Setaria viridis in twenty-eight 1 m x 1 m quadrats of Horqin Sandy Land were identified, mapped and described. The nearest neighbor method and O-ring O(r) function analysis were applied to analyze the spatial patterns. The results showed that the individual spatial pattern was mainly aggregated in 1 m x 1 m quadrat at community level but mainly random at population level. At 0-50 cm individual distance scale, both intraspecific and interspecific relationship were facilitation and aggregated distribution occurred at some scales and varied with increasing plant abundance in 1 m x 1 m quadrat. In 0-40 cm, the aggregated distribution of S. viridis and A. aquarrosum increased obviously; in 10-20 cm, both intraspecific and interspecific aggregation increased; in 10-30 cm, the occurrence possibility of positive correlations between S. viridis and A. aquarrosum, S. viridis and C. candelabrum all increased; in 40-50 cm, the possibility of positive correlations between A. squarrosum and S. viridis, A. squarrosum and C. candelabrum all increased. Research on the three species components indicated that the growth rate of above-ground was faster than that of underground. S. viridis had the highest ratio of under-ground biomass to above-ground biomass but its nutritional organs' biomass ratio was medium. C. candelabrum allocated more biomass to propagative organs and stem, but A. squarrosum allocated more biomass to nutritional organs. Based on the spatial distribution and allometric characteristics, the three common species in moving sand dunes preferred r strategy in their life history. PMID:26995902

  4. University Students Leaving Relationships (USLR): Scale Development and Gender Differences in Decisions to Leave Romantic Relationships

    ERIC Educational Resources Information Center

    Hendy, Helen M.; Can, S. Hakan; Joseph, Lauren J.; Scherer, Cory R.

    2013-01-01

    The University Students Leaving Relationships scale was developed to identify student concerns when contemplating dissolution of romantic relationships. Participants included 1,106 students who rated the importance of issues when deciding to leave relationships. Factor analysis produced three dimensions: Missing the Relationship, Social…

  5. SIZE SCALING RELATIONSHIPS IN FRACTURE NETWORKS

    SciTech Connect

    Thomas H. Wilson

    2000-01-01

    The research conducted under DOE grant DE-FG26-98FT40385 provides a detailed assessment of size scaling issues in natural fracture and active fault networks that extend over scales from several tens of kilometers to less than a tenth of a meter. This study incorporates analysis of data obtained from several sources, including: natural fracture patterns photographed in the Appalachian field area, natural fracture patterns presented by other workers in the published literature, patterns of active faulting in Japan mapping at a scale of 1:100,000, and lineament patterns interpreted from satellite-based radar imagery obtained over the Appalachian field area. The complexity of these patterns is always found to vary with scale. In general,but not always, patterns become less complex with scale. This tendency may reverse as can be inferred from the complexity of high-resolution radar images (8 meter pixel size) which are characterized by patterns that are less complex than those observed over smaller areas on the ground surface. Model studies reveal that changes in the complexity of a fracture pattern can be associated with dominant spacings between the fractures comprising the pattern or roughly to the rock areas bounded by fractures of a certain scale. While the results do not offer a magic number (the fractal dimension) to characterize fracture networks at all scales, the modeling and analysis provide results that can be interpreted directly in terms of the physical properties of the natural fracture or active fault complex. These breaks roughly define the size of fracture bounded regions at different scales. The larger more extensive sets of fractures will intersect and enclose regions of a certain size, whereas smaller less extensive sets will do the same--i.e. subdivide the rock into even smaller regions. The interpretation varies depending on the number of sets that are present, but the scale breaks in the logN/logr plots serve as a guide to interpreting the

  6. Exaggerated allometric structures in relation to demographic and ecological parameters in Lucanus cervus (Coleoptera: Lucanidae).

    PubMed

    Romiti, Federico; Tini, Massimiliano; Redolfi De Zan, Lara; Chiari, Stefano; Zauli, Agnese; Carpaneto, Giuseppe M

    2015-10-01

    Enlarged weapons and ornamental traits under sexual selection often show a positive allometric relationship with the overall body size. The present study explores the allometry of mandibles and their supporting structure, the head, in males of the European stag beetle, Lucanus cervus. This species shows a remarkable dimorphism in mandible shape and size that are used by males in intraspecific combats. Stag beetles were captured, measured, weighed, and released in the framework of a capture-mark-recapture study. The relationship of mandible length (ML) and head width in respect to the overall body size was described by a segmented regression model. A linear relationship was detected between ML and head width. The scaling relationships for both ML and head width identified the same switchpoint, highlighting the advantages of using combined results of weapons and their supporting structures in such analysis. These results led to a more consistent distinction of males in two morphologies: minor and major. The survival probability of individuals was dependent on the morphological class and was higher for minor males than for major. Elytron length and body mass of the individuals did not show any significant variation during the season. Differences in predatory pressure were detected between morphs by the collection and analysis of body fragments due to the predatory activity of corvids. Morphological differences and shift in demographic and ecological parameters between the two classes suggested that selection continues to favor intrasexual dimorphism in this species throughout a trade-off mechanism between costs and benefits of carrying exaggerated traits. PMID:26220669

  7. Spatial autocorrelation and the scaling of species-environment relationships.

    PubMed

    De Knegt, H J; van Langevelde, F; Coughenour, M B; Skidmore, A K; de Boer, W F; Heitkönig, I M A; Knox, N M; Slotow, R; van der Waal, C; Prins, H H T

    2010-08-01

    Issues of residual spatial autocorrelation (RSA) and spatial scale are critical to the study of species-environment relationships, because RSA invalidates many statistical procedures, while the scale of analysis affects the quantification of these relationships. Although these issues independently are widely covered in the literature, only sparse attention is given to their integration. This paper focuses on the interplay between RSA and the spatial scaling of species-environment relationships. Using a hypothetical species in an artificial landscape, we show that a mismatch between the scale of analysis and the scale of a species' response to its environment leads to a decrease in the portion of variation explained by environmental predictors. Moreover, it results in RSA and biased regression coefficients. This bias stems from error-predictor dependencies due to the scale mismatch, the magnitude of which depends on the interaction between the scale of landscape heterogeneity and the scale of a species' response to this heterogeneity. We show that explicitly considering scale effects on RSA can reveal the characteristic scale of a species' response to its environment. This is important, because the estimation of species-environment relationships using spatial regression methods proves to be erroneous in case of a scale mismatch, leading to spurious conclusions when scaling issues are not explicitly considered. The findings presented here highlight the importance of examining the appropriateness of the spatial scales used in analyses, since scale mismatches affect the rigor of statistical analyses and thereby the ability to understand the processes underlying spatial patterning in ecological phenomena. PMID:20836467

  8. Interspecies allometric meta-analysis of the comparative pharmacokinetics of 85 drugs across veterinary and laboratory animal species.

    PubMed

    Huang, Q; Gehring, R; Tell, L A; Li, M; Riviere, J E

    2015-06-01

    Allometric scaling is widely used for the determination of first dosage regimen and the interpolation or extrapolation of pharmacokinetic parameters across many animal species during drug development. In this article, 85 drugs used in veterinary medicine obtained from the Food Animal Residue Avoidance Databank database were selected for allometric scaling analysis. Outlier species were identified by statistical methods. The results showed that 77% and 88% of drugs displayed significant correlations between total systemic clearance (CL) and volume of distribution at steady status (Vss) vs. body weight (P < 0.05) on a log-log scale, respectively. The distribution of the allometric exponent b for CL and Vss displays approximate normal distribution, with means (0.87 and 0.99) and standard deviations (0.143 and 0.157) for CL and Vss, respectively. Twelve drugs were identified to have at least one outlier species for CL and ten drugs for Vss. The human CL and Vss were predicted for selected drugs by the obtained allometric equations. The predicted CL and Vss were within a threefold error compared to observed values, except the predicted CL values for antipyrine, warfarin and diazepam. The results can be used to estimate cross-species pharmacokinetic profiles for predicting drug dosages in veterinary species, and to identify those species for which interpolation or extrapolation of pharmacokinetics properties may be problematic. PMID:25333341

  9. A modeling framework for inferring tree growth and allocation from physiological, morphological and allometric traits.

    PubMed

    Ogle, Kiona; Pacala, Stephen W

    2009-04-01

    Predictions of forest succession, diversity and function require an understanding of how species differ in their growth, allocation patterns and susceptibility to mortality. These processes in turn are affected by allometric constraints and the physiological state of the tree, both of which are coupled to the tree's labile carbon status. Ultimately, insight into the hidden labile pools and the processes affecting the allocation of labile carbon to storage, maintenance and growth will improve our ability to predict tree growth, mortality and forest dynamics. We developed the 'Allometrically Constrained Growth and Carbon Allocation' (ACGCA) model that explicitly couples tree growth, mortality, allometries and labile carbon. This coupling results in (1) a semi-mechanistic basis for predicting tree death, (2) an allocation scheme that simultaneously satisfies allometric relationships and physiology-based carbon dynamics and (3) a range of physiological states that are consistent with tree behavior (e.g., healthy, static, shrinking, recovering, recovered and dead). We present the ACGCA model and illustrate aspects of its behavior by conducting simulations under different forest gap dynamics scenarios and with parameter values obtained for two ecologically dissimilar species: loblolly pine (Pinus taeda L.) and red maple (Acer rubrum L.). The model reproduces growth and mortality patterns of these species that are consistent with their shade-tolerance and succession status. The ACGCA framework provides an alternative, and potentially improved, approach for predicting tree growth, mortality and forest dynamics. PMID:19203984

  10. Theoretical Heterogeneous Catalysis: Scaling Relationships and Computational Catalyst Design.

    PubMed

    Greeley, Jeffrey

    2016-06-01

    Scaling relationships are theoretical constructs that relate the binding energies of a wide variety of catalytic intermediates across a range of catalyst surfaces. Such relationships are ultimately derived from bond order conservation principles that were first introduced several decades ago. Through the growing power of computational surface science and catalysis, these concepts and their applications have recently begun to have a major impact in studies of catalytic reactivity and heterogeneous catalyst design. In this review, the detailed theory behind scaling relationships is discussed, and the existence of these relationships for catalytic materials ranging from pure metal to oxide surfaces, for numerous classes of molecules, and for a variety of catalytic surface structures is described. The use of the relationships to understand and elucidate reactivity trends across wide classes of catalytic surfaces and, in some cases, to predict optimal catalysts for certain chemical reactions, is explored. Finally, the observation that, in spite of the tremendous power of scaling relationships, their very existence places limits on the maximum rates that may be obtained for the catalyst classes in question is discussed, and promising strategies are explored to overcome these limitations to usher in a new era of theory-driven catalyst design. PMID:27088666

  11. Allometric secular change in the long bones from the 1800s to the present.

    PubMed

    Meadows, L; Jantz, R L

    1995-09-01

    Allometric secular changes in the six long limb bones for White and Black males from the mid 1800s to the present are examined. Long bone lengths are available from the Terry collection and WWII casualties. We conducted two types of analysis to reveal secular changes. First, allometry scaling coefficients were derived by regressing log bone length onto log stature. These showed that the femur, tibia and fibula were positively allometric with stature, while the humerus, radius and ulna were isometric. The lower limb bones were more positively allometric in the WWII sample than in the Terry sample. Second, secular changes in length of femur and tibia and in the tibia/femur ratio were evaluated, using modern forensic cases in addition to the Terry and WWII samples. This analysis shows that secular increase in lower limb bone length is accompanied by relatively longer tibiae. Secular changes in proportion may render stature formulae based on nineteenth century samples, such as the Terry collection, inappropriate for modern forensic cases. The positive allometry of the lower limb bones argues against using simple femur/stature ratio, which assumes constant proportionality, as an alternative to regression equations. PMID:7595319

  12. Similitude requirements and scaling relationships as applied to model testing

    NASA Technical Reports Server (NTRS)

    Wolowicz, C. H.; Brown, J. S., Jr.; Gilbert, W. P.

    1979-01-01

    The similitude requirements for the most general test conditions are presented. These similitude requirements are considered in relation to the scaling relationships, test technique, test conditions (including supersonic flow), and test objectives. Particular emphasis is placed on satisfying the various similitude requirements for incompressible and compressible flow conditions. For free flying models tests, the test velocities for incompressible flow are scaled from Froude number similitude requirements and those for compressible flow are scaled from Mach number similitude requirements. The limitations of various test techniques are indicated, with emphasis on the free flying model.

  13. Higher Education Scale and Employment Relationship in China

    ERIC Educational Resources Information Center

    Zhao, Gui-zhi

    2009-01-01

    This paper reviews Chinese management research since its beginning more than thirty years ago. It then discusses the possible interplay between higher education scale and employment relationship, and suggests that it is time to take the road less traveled rather than to over-travel the more popular road. We conclude that the practice will prove…

  14. Cross-Scale Interactions and the Distribution-Abundance Relationship

    PubMed Central

    Werner, Earl E.; Davis, Christopher J.; Skelly, David K.; Relyea, Rick A.; Benard, Michael F.; McCauley, Shannon J.

    2014-01-01

    Positive interspecific relationships between local abundance and extent of regional distribution are among the most ubiquitous patterns in ecology. Although multiple hypotheses have been proposed, the mechanisms underlying distribution-abundance (d-a) relationships remain poorly understood. We examined the intra- and interspecific distribution-abundance relationships for a metacommunity of 13 amphibian species sampled for 15 consecutive years. Mean density of larvae in occupied ponds was positively related to number of ponds occupied by species; employing the fraction of ponds uniquely available to each species this same relationship sharply decelerates. The latter relationship suggested that more abundant species inhabited most available habitats annually, whereas rarer species were dispersal limited. We inferred the mechanisms responsible for this pattern based on the dynamics of one species, Pseudacris triseriata, which transitioned between a rare, narrowly distributed species to a common, widely distributed species and then back again. Both transitions were presaged by marked changes in mean local densities driven by climatic effects on habitat quality. We identified threshold densities separating these population regime shifts that differed with landscape configuration. Our data suggest that these transitions were caused by strong cross-scale interactions between local resource/niche processes and larger scale metapopulation processes. The patterns we observed have relevance for understanding the mechanisms of interspecific d-a relationships and critical thresholds associated with habitat fragmentation. PMID:24875899

  15. Cross-scale interactions and the distribution-abundance relationship.

    PubMed

    Werner, Earl E; Davis, Christopher J; Skelly, David K; Relyea, Rick A; Benard, Michael F; McCauley, Shannon J

    2014-01-01

    Positive interspecific relationships between local abundance and extent of regional distribution are among the most ubiquitous patterns in ecology. Although multiple hypotheses have been proposed, the mechanisms underlying distribution-abundance (d-a) relationships remain poorly understood. We examined the intra- and interspecific distribution-abundance relationships for a metacommunity of 13 amphibian species sampled for 15 consecutive years. Mean density of larvae in occupied ponds was positively related to number of ponds occupied by species; employing the fraction of ponds uniquely available to each species this same relationship sharply decelerates. The latter relationship suggested that more abundant species inhabited most available habitats annually, whereas rarer species were dispersal limited. We inferred the mechanisms responsible for this pattern based on the dynamics of one species, Pseudacris triseriata, which transitioned between a rare, narrowly distributed species to a common, widely distributed species and then back again. Both transitions were presaged by marked changes in mean local densities driven by climatic effects on habitat quality. We identified threshold densities separating these population regime shifts that differed with landscape configuration. Our data suggest that these transitions were caused by strong cross-scale interactions between local resource/niche processes and larger scale metapopulation processes. The patterns we observed have relevance for understanding the mechanisms of interspecific d-a relationships and critical thresholds associated with habitat fragmentation. PMID:24875899

  16. Approaches to predicting broad-scale regime shifts using changing pattern-process relationships across scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding and predicting the occurrence of alternative ecosystem states (i.e., regime shifts) at broad scales is a pressing challenge for ecologists given the scope and nature of global change. In many cases, regime shifts at broad-scales are affected by pattern-process relationships across a ra...

  17. Scaling of Morphological Characters across Trait Type, Sex, and Environment.

    PubMed

    Voje, Kjetil Lysne

    2016-01-01

    Biological diversity is, to a large extent, a matter of variation in size. Proportional (isometric) scaling, where large and small individuals are magnified versions of each other, is often assumed to be the most common way morphological traits scale relative to overall size within species. However, the many traits showing nonproportional (allometric) scaling have motivated some of the most discussed hypotheses on scaling relationships in biology, like the positive allometry hypothesis for secondary sexual traits and the negative allometry hypothesis for genitals. I evaluate more than 3,200 allometric parameters from the literature and find that negative allometry, not isometry, is the expected scaling relationship of morphological traits within species. Slopes of secondary sexual traits are more often steeper compared with other traits, but slopes larger than unity are also common for traits not under sexual selection. The steepness of the allometric slope is accordingly a weak predictor of past and present patterns of selection. Scaling of genitals varies across taxonomic groups, but negative allometry of genitals in insects and spiders is a consistent pattern. Finally, I find indications that terrestrial organisms may have a different scaling of morphological traits overall compared with aquatic species. PMID:27277405

  18. The Brief Family Relationship Scale: A Brief Measure of the Relationship Dimension in Family Functioning

    PubMed Central

    Fok, Carlotta Ching Ting; Allen, James; Henry, David

    2011-01-01

    The Relationship dimension of the Family Environment Scale (FES; Moos & Moos, 1994), which consists of the Cohesion, Expressiveness, and Conflict subscales, measures a person's perception of the quality of their family relationship functioning. This study investigates an adaptation of the Relationship dimension of the FES for Alaska Native youth. We tested the adapted measure, the Brief Family Relationship Scale (BFRS), for psychometric properties and internal structure with 284 12 to18 year-old predominately Yup'ik Eskimo Alaska Native adolescents from rural, remote communities. This non-Western cultural group is hypothesized to display higher levels of collectivism traditionally organized around an extended kinship family structure. Results demonstrate a subset of the adapted items function satisfactorily, a three-response alternative format provided meaningful information, and the subscale's underlying structure is best described through three distinct first-order factors, organized under one higher order factor. Convergent and discriminant validity of the BFRS was assessed through correlational analysis. PMID:22084400

  19. The brief family relationship scale: a brief measure of the relationship dimension in family functioning.

    PubMed

    Fok, Carlotta Ching Ting; Allen, James; Henry, David

    2014-02-01

    The Relationship dimension of the Family Environment Scale, which consists of the Cohesion, Expressiveness, and Conflict subscales, measures a person's perception of the quality of his or her family relationship functioning. This study investigates an adaptation of the Relationship dimension of the Family Environment Scale for Alaska Native youth. The authors tested the adapted measure, the Brief Family Relationship Scale, for psychometric properties and internal structure with 284 12- to 18-year-old predominately Yup'ik Eskimo Alaska Native adolescents from rural, remote communities. This non-Western cultural group is hypothesized to display higher levels of collectivism traditionally organized around an extended kinship family structure. Results demonstrate a subset of the adapted items function satisfactorily, a three-response alternative format provided meaningful information, and the subscale's underlying structure is best described through three distinct first-order factors, organized under one higher order factor. Convergent and discriminant validity of the Brief Family Relationship Scale was assessed through correlational analysis. PMID:22084400

  20. Testing for size and allometric differences in fossil hominin body mass estimation.

    PubMed

    Uhl, Natalie M; Rainwater, Christopher W; Konigsberg, Lyle W

    2013-06-01

    Body size reconstructions of fossil hominins allow us to infer many things about their evolution and lifestyle, including diet, metabolic requirements, locomotion, and brain/body size relationships. The importance of these implications compels anthropologists to attempt body mass estimation from fragmentary fossil hominin specimens. Most calculations require a known "calibration" sample usually composed of modern humans or other extant apes. Caution must be taken in these analyses, as estimates are sensitive to overall size and allometric differences between the fossil hominin and the reference sample. PMID:23588924

  1. Geometric morphometric analysis of allometric variation in the mandibular morphology of the hominids of Atapuerca, Sima de los Huesos site.

    PubMed

    Rosas, Antonio; Bastir, Markus

    2004-06-01

    Allometry is an important factor of morphological integration that contributes to the organization of the phenotype and its variation. Variation in the allometric shape of the mandible is particularly important in hominid evolution because the mandible carries important taxonomic traits. Some of these traits are known to covary with size, particularly the retromolar space, symphyseal curvature, and position of the mental foramen. The mandible is a well studied system in the context of the evolutionary development of complex morphological structures because it is composed of different developmental units that are integrated within a single bone. In the present study, we investigated the allometric variation of two important developmental units that are separated by the inferior nerve (a branch of CN V3). We tested the null hypothesis that there would be no difference in allometric variation between the two components. Procrustes-based geometric morphometrics of 20 two-dimensional (2D) landmarks were analyzed by multivariate regressions of shape on size in samples from 121 humans, 48 chimpanzees, and 50 gorillas (all recent specimens), eight fossil hominids from Atapuerca, Sima de los Huesos (AT-SH), and 17 Neandertals. The findings show that in all of the examined species, there was significantly greater allometric variation in the supra-nerve unit than in the infra-nerve unit. The formation of the retromolar space exhibited an allometric relationship with the supra-nerve unit in all of the species studied. The formation of the chin-like morphology is an "apodynamic" feature of the infra-nerve unit in the AT-SH hominids. The results of this study support the hypothesis that allometry contributes to the organization of variation in complex morphological structures. PMID:15164343

  2. Spatial aggregation and the species-area relationship across scales.

    PubMed

    Grilli, Jacopo; Azaele, Sandro; Banavar, Jayanth R; Maritan, Amos

    2012-11-21

    There has been a considerable effort to understand and quantify the spatial distribution of species across different ecosystems. Relative species abundance (RSA), beta diversity and species-area relationship (SAR) are among the most used macroecological measures to characterize plants communities in forests. In this paper we introduce a simple phenomenological model based on Poisson cluster processes which allows us to exactly link RSA and beta diversity to SAR. The framework is spatially explicit and accounts for the spatial aggregation of conspecific individuals. Under the simplifying assumption of neutral theory, we derive an analytical expression for the SAR which reproduces tri-phasic behavior as sample area increases from local to continental scales, explaining how the tri-phasic behavior can be understood in terms of simple geometric arguments. We also find an expression for the endemic area relationship (EAR) and for the scaling of the RSA. PMID:22902426

  3. Scaling Relationships Based on Scaled Tank Mixing and Transfer Test Results

    SciTech Connect

    Piepel, Gregory F.; Holmes, Aimee E.; Heredia-Langner, Alejandro; Lee, Kearn P.; Kelly, Steven E.

    2014-01-01

    This report documents the statistical analyses performed (by Pacific Northwest National Laboratory for Washington River Protection Solutions) on data from 26 tests conducted using two scaled tanks (43 and 120 inches) in the Small Scale Mixing Demonstration platform. The 26 tests varied several test parameters, including mixer-jet nozzle velocity, base simulant, supernatant viscosity, and capture velocity. For each test, samples were taken pre-transfer and during five batch transfers. The samples were analyzed for the concentrations (lbs/gal slurry) of four primary components in the base simulants (gibbsite, stainless steel, sand, and ZrO2). The statistical analyses including modeling the component concentrations as functions of test parameters using stepwise regression with two different model forms. The resulting models were used in an equivalent performance approach to calculate values of scaling exponents (for a simple geometric scaling relationship) as functions of the parameters in the component concentration models. The resulting models and scaling exponents are displayed in tables and graphically. The sensitivities of component concentrations and scaling exponents to the test parameters are presented graphically. These results will serve as inputs to subsequent work by other researchers to develop scaling relationships that are applicable to full-scale tanks.

  4. Scaling Relationships Based on Scaled Tank Mixing and Transfer Test Results

    SciTech Connect

    Piepel, Gregory F.; Holmes, Aimee E.; Heredia-Langner, Alejandro

    2013-09-18

    This report documents the statistical analyses performed (by Pacific Northwest National Laboratory for Washington River Protection Solutions) on data from 26 tests conducted using two scaled tanks (43 and 120 inches) in the Small Scale Mixing Demonstration platform. The 26 tests varied several test parameters, including mixer-jet nozzle velocity, base simulant, supernatant viscosity, and capture velocity. For each test, samples were taken pre-transfer and during five batch transfers. The samples were analyzed for the concentrations (lbs/gal slurry) of four primary components in the base simulants (gibbsite, stainless steel, sand, and ZrO2). The statistical analyses including modeling the component concentrations as functions of test parameters using stepwise regression with two different model forms. The resulting models were used in an equivalent performance approach to calculate values of scaling exponents (for a simple geometric scaling relationship) as functions of the parameters in the component concentration models. The resulting models and scaling exponents are displayed in tables and graphically. The sensitivities of component concentrations and scaling exponents to the test parameters are presented graphically. These results will serve as inputs to subsequent work by other researchers to develop scaling relationships that are applicable to full-scale tanks.

  5. The Unidimensional Relationship Closeness Scale (URCS): Reliability and Validity Evidence for a New Measure of Relationship Closeness

    ERIC Educational Resources Information Center

    Dibble, Jayson L.; Levine, Timothy R.; Park, Hee Sun

    2012-01-01

    A fundamental dimension along which all social and personal relationships vary is closeness. The Unidimensional Relationship Closeness Scale (URCS) is a 12-item self-report scale measuring the closeness of social and personal relationships. The reliability and validity of the URCS were assessed with college dating couples (N = 192), female friends…

  6. Scaling relationships for mercury and gaseous propellant ion thrusters

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.; Kaufman, H. R.

    1978-01-01

    A model describing the doubly charged ion densities in argon and xenon ion thrusters is presented. Doubly charged ions are shown to be produced in significant numbers from both the neutral and singly ionized states. Doubly-to-singly charged ion density ratios calculated using this model are compared to experimental values of this ratio measured in the 15 cm multipole thruster using both propellants. Agreement between theory and experiment is shown to be good. Using this doubly charged ion model, and a similar one obtained previously for mercury, together with the constant neutral loss rate theory, Child's current density law and accelerator grid fabrication limitations, a set of scaling relationships are developed. These relationships show the propellant utilizations, thrust densities and discharge power levels that can be expected as thruster diameter and/or specific impulse are increased and doubly charged ion densities are held at acceptably low values.

  7. Mammalian phylogenetic diversity-area relationships at a continental scale

    PubMed Central

    Mazel, Florent; Renaud, Julien; Guilhaumon, François; Mouillot, David; Gravel, Dominique; Thuiller, Wilfried

    2015-01-01

    In analogy to the species-area relationship (SAR), one of the few laws in Ecology, the phylogenetic diversity-area relationship (PDAR) describes the tendency of phylogenetic diversity (PD) to increase with area. Although investigating PDAR has the potential to unravel the underlying processes shaping assemblages across spatial scales and to predict PD loss through habitat reduction, it has been little investigated so far. Focusing on PD has noticeable advantages compared to species richness (SR) since PD also gives insights on processes such as speciation/extinction, assembly rules and ecosystem functioning. Here we investigate the universality and pervasiveness of the PDAR at continental scale using terrestrial mammals as study case. We define the relative robustness of PD (compared to SR) to habitat loss as the area between the standardized PDAR and standardized SAR (i.e. standardized by the diversity of the largest spatial window) divided by the area under the standardized SAR only. This metric quantifies the relative increase of PD robustness compared to SR robustness. We show that PD robustness is higher than SR robustness but that it varies among continents. We further use a null model approach to disentangle the relative effect of phylogenetic tree shape and non random spatial distribution of evolutionary history on the PDAR. We find that for most spatial scales and for all continents except Eurasia, PDARs are not different from expected by a model using only the observed SAR and the shape of the phylogenetic tree at continental scale. Interestingly, we detect a strong phylogenetic structure of the Eurasian PDAR that can be predicted by a model that specifically account for a finer biogeographical delineation of this continent. In conclusion, the relative robustness of PD to habitat loss compared to species richness is determined by the phylogenetic tree shape but also depends on the spatial structure of PD. PMID:26649401

  8. Mammalian phylogenetic diversity-area relationships at a continental scale.

    PubMed

    Mazel, Florent; Renaud, Julien; Guilhaumon, François; Mouillot, David; Gravel, Dominique; Thuiller, Wilfried

    2015-10-01

    In analogy to the species-area relationship (SAR), one of the few laws in ecology, the phylogenetic diversity-area relationship (PDAR) describes the tendency of phylogenetic diversity (PD) to increase with area. Although investigating PDAR has the potential to unravel the underlying processes shaping assemblages across spatial scales and to predict PD loss through habitat reduction, it has been little investigated so far. Focusing on PD has noticeable advantages compared to species richness (SR), since PD also gives insights on processes such as speciation/extinction, assembly rules and ecosystem functioning. Here we investigate the universality and pervasiveness of the PDAR at continental scale using terrestrial mammals as study case. We define the relative robustness of PD (compared to SR) to habitat loss as the area between the standardized PDAR and standardized SAR (i.e., standardized by the diversity of the largest spatial window) divided by the area under the standardized SAR only. This metric quantifies the relative increase of PD robustness compared to SR robustness. We show that PD robustness is higher than SR robustness but that it varies among continents. We further use a null model approach to disentangle the relative effect of phylogenetic tree shape and nonrandom spatial distribution of evolutionary history on the PDAR. We find that, for most spatial scales and for all continents except Eurasia, PDARs are not different from expected by a model using only the observed SAR and the shape of the phylogenetic tree at continental scale. Interestingly, we detect a strong phylogenetic structure of the Eurasian PDAR that can be predicted by a model that specifically account for a finer biogeographical delineation of this continent. In conclusion, the relative robustness of PD to habitat loss compared to species richness is determined by the phylogenetic tree shape but also depends on the spatial structure of PD. PMID:26649401

  9. Scaling Relationship and Optimization of Double-Pulse Electroporation

    PubMed Central

    Sadik, Mohamed M.; Yu, Miao; Zheng, Mingde; Zahn, Jeffrey D.; Shan, Jerry W.; Shreiber, David I.; Lin, Hao

    2014-01-01

    The efficacy of electroporation is known to vary significantly across a wide variety of biological research and clinical applications, but as of this writing, a generalized approach to simultaneously improve efficiency and maintain viability has not been available in the literature. To address that discrepancy, we here outline an approach that is based on the mapping of the scaling relationships among electroporation-mediated molecular delivery, cellular viability, and electric pulse parameters. The delivery of Fluorescein-Dextran into 3T3 mouse fibroblast cells was used as a model system. The pulse was rationally split into two sequential phases: a first precursor for permeabilization, followed by a second one for molecular delivery. Extensive data in the parameter space of the second pulse strength and duration were collected and analyzed with flow cytometry. The fluorescence intensity correlated linearly with the second pulse duration, confirming the dominant role of electrophoresis in delivery. The delivery efficiency exhibited a characteristic sigmoidal dependence on the field strength. An examination of short-term cell death using 7-Aminoactinomycin D demonstrated a convincing linear correlation with respect to the electrical energy. Based on these scaling relationships, an optimal field strength becomes identifiable. A model study was also performed, and the results were compared with the experimental data to elucidate underlying mechanisms. The comparison reveals the existence of a critical transmembrane potential above which delivery with the second pulse becomes effective. Together, these efforts establish a general route to enhance the functionality of electroporation. PMID:24559983

  10. Large-scale directional relationship extraction and resolution

    PubMed Central

    Giles, Cory B; Wren, Jonathan D

    2008-01-01

    Background Relationships between entities such as genes, chemicals, metabolites, phenotypes and diseases in MEDLINE are often directional. That is, one may affect the other in a positive or negative manner. Detection of causality and direction is key in piecing pathways together and in examining possible implications of experimental results. Because of the size and growth of biomedical literature, it is increasingly important to be able to automate this process as much as possible. Results Here we present a method of relation extraction using dependency graph parsing with SVM classification. We tested the SVM classifier first on gold standard corpora from GENIA and find it achieved 82% precision and 94.8% recall (F-measure of 87.9) on these standardized test sets. We then applied the entire system to all available MEDLINE abstracts for two target interactions with known effects. We find that while some directional relations are extracted with low ambiguity, others are apparently contradictory, at least when considered in an isolated context. When examined, it is apparent some are dependent upon the surrounding context (e.g. whether the relationship referred to short-term or long-term effects, or whether the focus was extracellular versus intracellular). Conclusion Thesaurus-based directional relation extraction can be done with reasonable accuracy, but is prone to false-positives on larger corpora due to noun modifiers. Furthermore, methods of resolving or disambiguating relationship context and contingencies are important for large-scale corpora. PMID:18793456

  11. Using allometric procedures to substantiate the plastochrone method for eelgrass leaf growth assessments.

    PubMed

    Echavarría-Heras, Héctor; Solana-Arellano, Elena; Leal-Ramírez, Cecilia; Castillo, Oscar

    2013-01-01

    Estimation of leaf productivity in eelgrass (Zostera marina L.) is crucial for evaluating the ecological role of this important seagrass species. Although leaf marking techniques are widely used to obtain estimates of leaf productivity, the accuracy of these assessments, has been questioned mainly because these fail to account for leaf growth below the reference mark and also because they apparently disregard the contribution of mature leaf tissues to the growth rate of leaves. On the other hand, the plastochrone method is a simpler technique that has been considered to effectively capture growth in a more realistic way, thereby providing more accurate assessments of both above- and below-ground productivities. But since the actual values of eelgrass growth rates are difficult to obtain, the worth of the plastochrone method has been largely vindicated because it produces assessments that overestimate productivity as compared to estimates obtained by leaf marking. Additionally, whenever eelgrass leaf biomass can be allometrically scaled in terms of matching leaf length in a consistent way, the associated leaf growth rates can be also projected allometrically. In this contribution, we used that approach to derive an authentication of the plastochrone method and formally demonstrate that, as has been claimed to occur for leaf marking approaches, the plastochrone method itself underestimates actual values of eelgrass leaf growth rates. We also show that this unavoidable bias is mainly due to the inadequacy of single-leaf biomass assessments in providing a proxy for the growth of all leaf tissue in a shoot over a given interval. Moreover, the derived formulae give conditions under which assessments of leaf growth rates using the plastochrone method would systematically underestimate matching values obtained by leaf marking procedures. And, assessments of leaf growth rates obtained by using the present data show that plastochrone method estimations underestimated

  12. Modelling the determinants of 2000 m rowing ergometer performance: a proportional, curvilinear allometric approach.

    PubMed

    Nevill, A M; Allen, S V; Ingham, S A

    2011-02-01

    Previous studies have investigated the determinants of indoor rowing using correlations and linear regression. However, the power demands of ergometer rowing are proportional to the cube of the flywheel's (and boat's) speed. A rower's speed, therefore, should be proportional to the cube root (0.33) of power expended. Hence, the purpose of the present study was to explore the relationship between 2000 m indoor rowing speed and various measures of power of 76 elite rowers using proportional, curvilinear allometric models. The best single predictor of 2000 m rowing ergometer performance was power at VO(2max)(WVO(2max))(0.28), that explained R(2)=95.3% in rowing speed. The model realistically describes the greater increment in power required to improve a rower's performance by the same amount at higher speeds compared with that at slower speeds. Furthermore, the fitted exponent, 0.28 (95% confidence interval 0.226-0.334) encompasses 0.33, supporting the assumption that rowing speed is proportional to the cube root of power expended. Despite an R(2)=95.3%, the initial model was unable to explain "sex" and "weight-class" differences in rowing performances. By incorporating anaerobic as well as aerobic determinants, the resulting curvilinear allometric model was common to all rowers, irrespective of sex and weight class. PMID:19883389

  13. Sexual size dimorphism and allometric growth of Morelet's crocodiles in captivity.

    PubMed

    Barrios-Quiroz, Gabriel; Casas-Andreu, Gustavo; Escobedo-Galván, Armando H

    2012-03-01

    Few studies have conducted morphological analyses of crocodilians, and little information exists on differences between size-classes and sexes in Neotropical crocodilians. In this study, we measured nine morphological traits in 121 captive Morelet's crocodiles Crocodylus moreletii (81 females and 40 males). Our results revealed that individuals < 2 m total length do not exhibit sexual dimorphism in morphometric characteristics. However, for crocodiles over 2 m in length, males were significantly larger than females in terms of dorsal-cranial length, cranial width, snout width and snout-ventral length. In general, morphological traits demonstrated a strongly significant relationship with total length at the smaller size class of 150-200 cm length. However, in the highest size class of 250-300 cm length (large adult males), morphological traits were no longer significantly related with total length. Male crocodiles demonstrated allometric growth of cranial morphology with significantly greater increase in cranial width, snout width, and mid-snout width relative to total length at higher size classes. Morphological dimorphism and allometric growth may be associated with adaptive strategies for reproductive success. PMID:22379988

  14. An allometric approach to quantify the extinction vulnerability of birds and mammals.

    PubMed

    Hilbers, J P; Schipper, A M; Hendriks, A J; Verones, F; Pereira, H M; Huijbregts, M A J

    2016-03-01

    Methods to quantify the vulnerability of species to extinction are typically limited by the availability of species-specific input data pertaining to life-history characteristics and population dynamics. This lack of data hampers global biodiversity assessments and conservation planning. Here, we developed a new framework that systematically quantifies extinction risk based on allometric relationships between various wildlife demographic parameters and body size. These allometric relationships have a solid theoretical and ecological foundation. Extinction risk indicators included are (1) the probability of extinction, (2) the mean time to extinction, and (3) the critical patch size. We applied our framework to assess the global extinction vulnerability of terrestrial carnivorous and non-carnivorous birds and mammals. Irrespective of the indicator used, large-bodied species were found to be more vulnerable to extinction than their smaller counterparts. The patterns with body size were confirmed for all species groups by a comparison with IUCN data on the proportion of extant threatened species: the models correctly predicted a multimodal distribution with body size for carnivorous birds and a monotonic distribution for mammals and non-carnivorous birds. Carnivorous mammals were found to have higher extinction risks than non-carnivores, while birds were more prone to extinction than mammals. These results are explained by the allometric relationships, predicting the vulnerable species groups to have lower intrinsic population growth rates, smaller population sizes, lower carrying capacities, or larger dispersal distances, which, in turn, increase the importance of losses due to environmental stochastic effects and dispersal activities. Our study is the first to integrate population viability analysis and allometry into a novel, process-based framework that is able to quantify extinction risk of a large number of species without requiring data-intensive, species

  15. Mapping Urban Forest Leaf Area Index Using Lidar: A Comparison of Gap Fraction Inversion and Allometric Methods

    NASA Astrophysics Data System (ADS)

    Alonzo, M.; Bookhagen, B.; McFadden, J. P.; Sun, A.; Roberts, D. A.

    2014-12-01

    In urban areas leaf area index (LAI) is a key ecosystem structural attribute with implications for energy and water balance, gas exchange, and anthropogenic energy use. Typically, citywide LAI estimates are extrapolated from those made on forest inventory sample plots through intensive crown measurement and allometric scaling. This is a time- and labor-intensive process yielding coarse spatial resolution results. In this study we generate spatially explicit estimates of LAI using high-point density airborne lidar throughout our study area in downtown Santa Barbara, CA. We implement two theoretically distinct modeling approaches. First, based on hemispherical photography at our 71 field plots, we estimate effective LAI using scan-angle corrected lidar laser penetration metrics (LPM). For our second approach, we adapt existing allometric equations for use with a suite of crown structural metrics (e.g., tree height, crown base height) measured with lidar. This approach allows for estimates of LAI to be made at the individual tree crown scale (ITC). This is important for evaluating fine-scale interactions between canopy and urban surfaces. The LPM method resulted in good agreement with field estimates (r2 = 0.80) and a slope of near unity (β = 0.998) using a model that assumed a spherical leaf angle distribution. Within ITC segments that were automatically delineated using watershed segmentation, lidar estimates of crown structure closely paralleled field measurements (r2=0.87 for crown length). LAI estimates based on the lidar structural variables corresponded well with estimates from field measurements (r2 = 0.84). Agreement between the LPM and allometric lidar methods was also strong across the 71 validation plots (r2 = 0.88) and among 450 sample points (r2 = 0.72) randomly distributed throughout the citywide maps. This is notably higher than the agreement between the hemiphoto and allometric ground-based estimates (r2 = 0.56). The allometric approach generally

  16. Intron-genome size relationship on a large evolutionary scale.

    PubMed

    Vinogradov, A E

    1999-09-01

    The intron-genome size relationship was studied across a wide evolutionary range (from slime mold and yeast to human and maize), as well as the relationship between genome size and the ratio of intervening/coding sequence size. The average intron size is scaled to genome size with a slope of about one-fourth for the log-transformed values; i.e., on the global scale its increase in evolution is lower than the increase in genome size by four orders of magnitude. There are exceptions to the general trend. In baker's yeast introns are extraordinarily long for its genome size. Tetrapods also have longer introns than expected for their genome sizes. In teleost fish the mean intron size does not differ significantly, notwithstanding the differences in genome size. In contrast to previous reports, avian introns were not found to be significantly shorter than introns of mammals, although avian genomes are smaller than genomes of mammals on average by about a factor of 2.5. The extra-/intragenic ratio of noncoding DNA can be higher in fungi than in animals, notwithstanding the smaller fungal genomes. In vertebrates and invertebrates taken separately, this ratio is increasing as the increase in genome size. Two hypotheses are proposed to explain the variation in the extra-/intragenic ratio of noncoding DNA in organisms with similar numbers of genes: transition (dynamic) and equilibrium (static). According to the transition model, this variation arises with the rapid shift of genome size because the bulk of extragenic DNA can be changed more rapidly than the finely interspersed intron sequences. The equilibrium model assumes that this variation is a result of selective adjustment of genome size with constraints imposed on the intron size due to its putative link to chromatin structure (and constraints of the splicing machinery). PMID:10473779

  17. Ontogenetic study of allometric variation in Homo and Pan mandibles.

    PubMed

    Singh, Nandini

    2014-02-01

    Investigating ontogenetic variation and allometry in the mandible can provide valuable insight and aid in addressing questions related to the ontogeny of the skull. Here, patterns of ontogenetic shape change and allometric trajectories were examined in the mandible of 187 sub-adult and adult humans, bonobos, and chimpanzees. Procrustes-based geometric morphometrics was employed to quantify and analyze mandibular form. Thirty three-dimensional landmarks were used to capture the overall morphology of the mandible, and the landmarks were analyzed as a whole and subdivided into separate anterior and posterior units. Principal component analyses in Procrustes shape-space and form-space, and multivariate regressions were used to examine patterns of ontogenetic and allometric shape change. Results suggest that humans are distinct from Pan both in their mandibular morphology, particularly in the anterior-alveolar region, and direction of allometric trajectory. Chimpanzees and bonobos have parallel ontogenetic trajectories, but also show differences in mandibular shape. Species-specific features and adult mandibular shape are established before or by the eruption of the deciduous dentition. This suggests that developmental processes prior to deciduous teeth eruption have a stronger effect establishing taxa-specific phenotypes than later postnatal effects. This additionally implies that divergent trajectories between Pan and Homo do not contribute much to the adult mandibular shape after deciduous teeth eruption. Separate analyses of the anterior-alveolar region and ascending ramus show that these regions are semi-independent in their developmental pattern of shape change and allometry. This implies that allometric variation and ontogenetic shape change in the hominoid mandible is decoupled. PMID:24347386

  18. Scaling Relationships between Leaf Mass and Total Plant Mass across Chinese Forests

    PubMed Central

    Xu, Shanshan; Li, Yan; Wang, Genxuan

    2014-01-01

    Biomass partitioning is important for illustrating terrestrial ecosystem carbon flux. West, Brown and Enquist (WBE) model predicts that an optimal 3/4 allometric scaling of leaf mass and total biomass of individual plants will be applied in diverse communities. However, amount of scientific evidence suggests an involvement of some biological and environmental factors in interpreting the variation of scaling exponent observed in empirical studies. In this paper, biomass information of 1175 forested communities in China was collected and categorized into groups in terms of leaf form and function, as well as their locations to test whether the allocation pattern was conserved or variable with internal and/or environmental variations. Model Type II regression protocol was adopted to perform all the regressions. The results empirically showed that the slopes varied significantly across diverse forested biomes, between conifer and broadleaved forests, and between evergreen and deciduous forests. Based on the results, leaf form and function and their relations to environments play a significant role in the modification of the WBE model to explore more accurate laws in nature. PMID:24759801

  19. Scaling relationships between leaf mass and total plant mass across Chinese forests.

    PubMed

    Xu, Shanshan; Li, Yan; Wang, Genxuan

    2014-01-01

    Biomass partitioning is important for illustrating terrestrial ecosystem carbon flux. West, Brown and Enquist (WBE) model predicts that an optimal 3/4 allometric scaling of leaf mass and total biomass of individual plants will be applied in diverse communities. However, amount of scientific evidence suggests an involvement of some biological and environmental factors in interpreting the variation of scaling exponent observed in empirical studies. In this paper, biomass information of 1175 forested communities in China was collected and categorized into groups in terms of leaf form and function, as well as their locations to test whether the allocation pattern was conserved or variable with internal and/or environmental variations. Model Type II regression protocol was adopted to perform all the regressions. The results empirically showed that the slopes varied significantly across diverse forested biomes, between conifer and broadleaved forests, and between evergreen and deciduous forests. Based on the results, leaf form and function and their relations to environments play a significant role in the modification of the WBE model to explore more accurate laws in nature. PMID:24759801

  20. Root–shoot allometry of tropical forest trees determined in a large-scale aeroponic system

    PubMed Central

    Eshel, Amram; Grünzweig, José M.

    2013-01-01

    Background and Aims This study is a first step in a multi-stage project aimed at determining allometric relationships among the tropical tree organs, and carbon fluxes between the various tree parts and their environment. Information on canopy–root interrelationships is needed to improve understanding of above- and below-ground processes and for modelling of the regional and global carbon cycle. Allometric relationships between the sizes of different plant parts will be determined. Methods Two tropical forest species were used in this study: Ceiba pentandra (kapok), a fast-growing tree native to South and Central America and to Western Africa, and Khaya anthotheca (African mahogany), a slower-growing tree native to Central and Eastern Africa. Growth and allometric parameters of 12-month-old saplings grown in a large-scale aeroponic system and in 50-L soil containers were compared. The main advantage of growing plants in aeroponics is that their root systems are fully accessible throughout the plant life, and can be fully recovered for harvesting. Key Results The expected differences in shoot and root size between the fast-growing C. pentandra and the slower-growing K. anthotheca were evident in both growth systems. Roots were recovered from the aeroponically grown saplings only, and their distribution among various diameter classes followed the patterns expected from the literature. Stem, branch and leaf allometric parameters were similar for saplings of each species grown in the two systems. Conclusions The aeroponic tree growth system can be utilized for determining the basic allometric relationships between root and shoot components of these trees, and hence can be used to study carbon allocation and fluxes of whole above- and below-ground tree parts. PMID:23250916

  1. A spatial scaling relationship for soil moisture in a semiarid landscape, using spatial scaling relationships for pedology

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.; Chen, M.; Cohen, S.; Saco, P. M.; Hancock, G. R.

    2013-12-01

    In humid areas it is generally considered that soil moisture scales spatially according to the wetness index of the landscape. This scaling arises from lateral flow downslope of ground water within the soil zone. However, in semi-arid and drier regions, this lateral flow is small and fluxes are dominated by vertical flows driven by infiltration and evapotranspiration. Thus, in the absence of runon processes, soil moisture at a location is more driven by local factors such as soil and vegetation properties at that location rather than upstream processes draining to that point. The 'apparent' spatial randomness of soil and vegetation properties generally suggests that soil moisture for semi-arid regions is spatially random. In this presentation a new analysis of neutron probe data during summer from the Tarrawarra site near Melbourne, Australia shows persistent spatial organisation of soil moisture over several years. This suggests a link between permanent features of the catchment (e.g. soil properties) and soil moisture distribution, even though the spatial pattern of soil moisture during the 4 summers monitored appears spatially random. This and other data establishes a prima facie case that soil variations drive spatial variation in soil moisture. Accordingly, we used a previously published spatial scaling relationship for soil properties derived using the mARM pedogenesis model to simulate the spatial variation of soil grading. This soil grading distribution was used in the Rosetta pedotransfer model to derive a spatial distribution of soil functional properties (e.g. saturated hydraulic conductivity, porosity). These functional properties were then input into the HYDRUS-1D soil moisture model and soil moisture simulated for 3 years at daily resolution. The HYDRUS model used had previously been calibrated to field observed soil moisture data at our SASMAS field site. The scaling behaviour of soil moisture derived from this modelling will be discussed and

  2. Metabolic scaling in animals: methods, empirical results, and theoretical explanations.

    PubMed

    White, Craig R; Kearney, Michael R

    2014-01-01

    Life on earth spans a size range of around 21 orders of magnitude across species and can span a range of more than 6 orders of magnitude within species of animal. The effect of size on physiology is, therefore, enormous and is typically expressed by how physiological phenomena scale with mass(b). When b ≠ 1 a trait does not vary in direct proportion to mass and is said to scale allometrically. The study of allometric scaling goes back to at least the time of Galileo Galilei, and published scaling relationships are now available for hundreds of traits. Here, the methods of scaling analysis are reviewed, using examples for a range of traits with an emphasis on those related to metabolism in animals. Where necessary, new relationships have been generated from published data using modern phylogenetically informed techniques. During recent decades one of the most controversial scaling relationships has been that between metabolic rate and body mass and a number of explanations have been proposed for the scaling of this trait. Examples of these mechanistic explanations for metabolic scaling are reviewed, and suggestions made for comparing between them. Finally, the conceptual links between metabolic scaling and ecological patterns are examined, emphasizing the distinction between (1) the hypothesis that size- and temperature-dependent variation among species and individuals in metabolic rate influences ecological processes at levels of organization from individuals to the biosphere and (2) mechanistic explanations for metabolic rate that may explain the size- and temperature-dependence of this trait. PMID:24692144

  3. Mixed-power scaling of whole-plant respiration from seedlings to giant trees

    PubMed Central

    Mori, Shigeta; Yamaji, Keiko; Ishida, Atsushi; Prokushkin, Stanislav G.; Masyagina, Oxana V.; Hagihara, Akio; Hoque, A.T.M. Rafiqul; Suwa, Rempei; Osawa, Akira; Nishizono, Tomohiro; Ueda, Tatsushiro; Kinjo, Masaru; Miyagi, Tsuyoshi; Kajimoto, Takuya; Koike, Takayoshi; Matsuura, Yojiro; Toma, Takeshi; Zyryanova, Olga A.; Abaimov, Anatoly P.; Awaya, Yoshio; Araki, Masatake G.; Kawasaki, Tatsuro; Chiba, Yukihiro; Umari, Marjnah

    2010-01-01

    The scaling of respiratory metabolism with body mass is one of the most pervasive phenomena in biology. Using a single allometric equation to characterize empirical scaling relationships and to evaluate alternative hypotheses about mechanisms has been controversial. We developed a method to directly measure respiration of 271 whole plants, spanning nine orders of magnitude in body mass, from small seedlings to large trees, and from tropical to boreal ecosystems. Our measurements include the roots, which have often been ignored. Rather than a single power-law relationship, our data are fit by a biphasic, mixed-power function. The allometric exponent varies continuously from 1 in the smallest plants to 3/4 in larger saplings and trees. Therefore, our findings support the recent findings of Reich et al. [Reich PB, Tjoelker MG, Machado JL, Oleksyn J (2006) Universal scaling of respiratory metabolism, size, and nitrogen in plants. Nature 439:457–461] and West, Brown, and Enquist [West GB, Brown JH, Enquist BJ (1997) A general model for the origin of allometric scaling laws in biology. Science 276:122 -126.]. The transition from linear to 3/4-power scaling may indicate fundamental physical and physiological constraints on the allocation of plant biomass between photosynthetic and nonphotosynthetic organs over the course of ontogenetic plant growth. PMID:20080600

  4. Burrowing energetics of the Giant Burrowing Cockroach Macropanesthia rhinoceros: an allometric study.

    PubMed

    Xu, Liangwen; Snelling, Edward P; Seymour, Roger S

    2014-11-01

    Burrowing is an important life strategy for many insects, yet the energetic cost of constructing burrows has never been studied in insects of different sizes. Open flow respirometry was used to determine the allometric scaling of standard metabolic rate (MRS) and burrowing metabolic rate (MRB) in the heaviest extant cockroach species, the Giant Burrowing Cockroach Macropanesthia rhinoceros, at different stages of development. At 10 °C, MRS (mW) scales with body mass (M; g) according to the allometric power equation, MRS=0.158M(0.74), at 20 °C the equation is MRS=0.470M(0.53), and at 30 °C the equation is MRS=1.22M(0.49) (overall Q10=2.23). MRS is much lower in M. rhinoceros compared to other insect species, which is consistent with several aspects of their life history, including flightlessness, extreme longevity (>5 years), burrowing, parental behaviour, and an energy-poor diet (dry eucalypt leaf litter). Energy expenditure during burrowing at 25 °C scales according to MRB=16.9M(0.44), and is approximately 17 times higher than resting rates measured at the same temperature, although the metabolic cost over a lifetime is probably low, because the animal does not burrow to find food. The net cost of transport by burrowing (Jm(-1)) scales according to NCOT=120M(0.49), and reflects the energetically demanding task of burrowing compared to other forms of locomotion. The net cost of excavating the soil (J cm(-3)) is statistically independent of body size. PMID:25257537

  5. A scaling relationship between AE and natural earthquakes

    NASA Astrophysics Data System (ADS)

    Yoshimitsu, N.; Kawakata, H.; Takahashi, N.

    2013-12-01

    seismic moments and the corner frequencies by grid search. The magnitude of AE events were estimated between -8 to -7. As a result, the relationship between the seismic moment and the corner frequency of AE also satisfied the same scaling relationship as shown for natural earthquakes. This indicates that AE in rock samples can be regarded as micro size earthquake. This finding shows the possibility to understand the developing processes of natural earthquake from laboratory experiments.

  6. Large Scale Relationship between Aquatic Insect Traits and Climate

    PubMed Central

    Bhowmik, Avit Kumar; Schäfer, Ralf B.

    2015-01-01

    Climate is the predominant environmental driver of freshwater assemblage pattern on large spatial scales, and traits of freshwater organisms have shown considerable potential to identify impacts of climate change. Although several studies suggest traits that may indicate vulnerability to climate change, the empirical relationship between freshwater assemblage trait composition and climate has been rarely examined on large scales. We compared the responses of the assumed climate-associated traits from six grouping features to 35 bioclimatic indices (~18 km resolution) for five insect orders (Diptera, Ephemeroptera, Odonata, Plecoptera and Trichoptera), evaluated their potential for changing distribution pattern under future climate change and identified the most influential bioclimatic indices. The data comprised 782 species and 395 genera sampled in 4,752 stream sites during 2006 and 2007 in Germany (~357,000 km² spatial extent). We quantified the variability and spatial autocorrelation in the traits and orders that are associated with the combined and individual bioclimatic indices. Traits of temperature preference grouping feature that are the products of several other underlying climate-associated traits, and the insect order Ephemeroptera exhibited the strongest response to the bioclimatic indices as well as the highest potential for changing distribution pattern. Regarding individual traits, insects in general and ephemeropterans preferring very cold temperature showed the highest response, and the insects preferring cold and trichopterans preferring moderate temperature showed the highest potential for changing distribution. We showed that the seasonal radiation and moisture are the most influential bioclimatic aspects, and thus changes in these aspects may affect the most responsive traits and orders and drive a change in their spatial distribution pattern. Our findings support the development of trait-based metrics to predict and detect climate

  7. Large Scale Relationship between Aquatic Insect Traits and Climate.

    PubMed

    Bhowmik, Avit Kumar; Schäfer, Ralf B

    2015-01-01

    Climate is the predominant environmental driver of freshwater assemblage pattern on large spatial scales, and traits of freshwater organisms have shown considerable potential to identify impacts of climate change. Although several studies suggest traits that may indicate vulnerability to climate change, the empirical relationship between freshwater assemblage trait composition and climate has been rarely examined on large scales. We compared the responses of the assumed climate-associated traits from six grouping features to 35 bioclimatic indices (~18 km resolution) for five insect orders (Diptera, Ephemeroptera, Odonata, Plecoptera and Trichoptera), evaluated their potential for changing distribution pattern under future climate change and identified the most influential bioclimatic indices. The data comprised 782 species and 395 genera sampled in 4,752 stream sites during 2006 and 2007 in Germany (~357,000 km² spatial extent). We quantified the variability and spatial autocorrelation in the traits and orders that are associated with the combined and individual bioclimatic indices. Traits of temperature preference grouping feature that are the products of several other underlying climate-associated traits, and the insect order Ephemeroptera exhibited the strongest response to the bioclimatic indices as well as the highest potential for changing distribution pattern. Regarding individual traits, insects in general and ephemeropterans preferring very cold temperature showed the highest response, and the insects preferring cold and trichopterans preferring moderate temperature showed the highest potential for changing distribution. We showed that the seasonal radiation and moisture are the most influential bioclimatic aspects, and thus changes in these aspects may affect the most responsive traits and orders and drive a change in their spatial distribution pattern. Our findings support the development of trait-based metrics to predict and detect climate

  8. Scaling Relationships for ELM Diverter Heat Flux on DIII D

    NASA Astrophysics Data System (ADS)

    Peters, E. A.; Makowski, M. A.; Leonard, A. W.

    2015-11-01

    Edge Localized Modes (ELMs) are periodic plasma instabilities that occur during H-mode operation in tokamaks. Left unmitigated, these instabilities result in concentrated particle and heat fluxes at the divertor and stand to cause serious damage to the plasma facing components of tokamaks. The purpose of this research is to find scaling relationships that predict divertor heat flux due to ELMs based on plasma parameters at the time of instability. This will be accomplished by correlating characteristic ELM parameters with corresponding plasma measurements and analyzing the data for trends. One early assessment is the effect of the heat transmission coefficient ? on the in/out asymmetry of the calculated ELM heat fluxes. Using IR camera data, further assessments in this study will continue to emphasize in/out asymmetry in ELMs, as this has important implications for ITER operation. Work supported in part by the US DOE, DE-AC52-07NA27344, DE-FC02-04ER54698, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internships Program (SULI).

  9. Improved allometric models to estimate the aboveground biomass of tropical trees.

    PubMed

    Chave, Jérôme; Réjou-Méchain, Maxime; Búrquez, Alberto; Chidumayo, Emmanuel; Colgan, Matthew S; Delitti, Welington B C; Duque, Alvaro; Eid, Tron; Fearnside, Philip M; Goodman, Rosa C; Henry, Matieu; Martínez-Yrízar, Angelina; Mugasha, Wilson A; Muller-Landau, Helene C; Mencuccini, Maurizio; Nelson, Bruce W; Ngomanda, Alfred; Nogueira, Euler M; Ortiz-Malavassi, Edgar; Pélissier, Raphaël; Ploton, Pierre; Ryan, Casey M; Saldarriaga, Juan G; Vieilledent, Ghislain

    2014-10-01

    Terrestrial carbon stock mapping is important for the successful implementation of climate change mitigation policies. Its accuracy depends on the availability of reliable allometric models to infer oven-dry aboveground biomass of trees from census data. The degree of uncertainty associated with previously published pantropical aboveground biomass allometries is large. We analyzed a global database of directly harvested trees at 58 sites, spanning a wide range of climatic conditions and vegetation types (4004 trees ≥ 5 cm trunk diameter). When trunk diameter, total tree height, and wood specific gravity were included in the aboveground biomass model as covariates, a single model was found to hold across tropical vegetation types, with no detectable effect of region or environmental factors. The mean percent bias and variance of this model was only slightly higher than that of locally fitted models. Wood specific gravity was an important predictor of aboveground biomass, especially when including a much broader range of vegetation types than previous studies. The generic tree diameter-height relationship depended linearly on a bioclimatic stress variable E, which compounds indices of temperature variability, precipitation variability, and drought intensity. For cases in which total tree height is unavailable for aboveground biomass estimation, a pantropical model incorporating wood density, trunk diameter, and the variable E outperformed previously published models without height. However, to minimize bias, the development of locally derived diameter-height relationships is advised whenever possible. Both new allometric models should contribute to improve the accuracy of biomass assessment protocols in tropical vegetation types, and to advancing our understanding of architectural and evolutionary constraints on woody plant development. PMID:24817483

  10. Prediction of human drug clearance from two species: a comparison of several allometric methods.

    PubMed

    Goteti, Kosalaram; Garner, C Edwin; Mahmood, Iftekhar

    2010-03-01

    The objective of the study was to assess the degree of accuracy in human drug clearance prediction from two species using four different allometric approaches: simple allometry (SA), multiexponential allometry (ME), rule of exponents (ROE), and fixed exponents (FE) as suggested by Tang et al. There were 45 compounds in this analysis and the two species used were either rat-dog or rat-monkey. In addition, > or = 3 species scaling was also performed to evaluate the comparative accuracy in the prediction of human drug clearance between two or more than two-species scaling. The results of the study indicated that the two-species scaling with different methods provided different degrees of accuracy in the prediction of clearance. Prediction by a particular method was also species dependent. For example, a given drug with rat-dog scaling provided a reasonably accurate prediction of clearance whereas with rat-monkey scaling the prediction of clearance was highly erratic or vice versa. The results of the study indicated that the two-species scaling can be useful for prediction purposes but the prediction of clearance from > or = 3 species was far more accurate than two-species scaling. PMID:19827101

  11. RE-EXAMINING LARSON'S SCALING RELATIONSHIPS IN GALACTIC MOLECULAR CLOUDS

    SciTech Connect

    Heyer, Mark; Krawczyk, Coleman; Duval, Julia; Jackson, James M.

    2009-07-10

    The properties of Galactic molecular clouds tabulated by Solomon et al. (SRBY) are re-examined using the Boston University-FCRAO Galactic Ring Survey of {sup 13}CO J = 1-0 emission. These new data provide a lower opacity tracer of molecular clouds and improved angular and spectral resolution compared with previous surveys of molecular line emission along the Galactic Plane. We calculate giant molecular cloud (GMC) masses within the SRBY cloud boundaries assuming local thermodynamic equilibrium (LTE) conditions throughout the cloud and a constant H{sub 2} to {sup 13}CO abundance, while accounting for the variation of the {sup 12}C/{sup 13}C with galactocentric radius. The LTE-derived masses are typically five times smaller than the SRBY virial masses. The corresponding median mass surface density of molecular hydrogen for this sample is 42 M{sub sun} pc{sup -2}, which is significantly lower than the value derived by SRBY (median 206 M{sub sun} pc{sup -2}) that has been widely adopted by most models of cloud evolution and star formation. This discrepancy arises from both the extrapolation by SRBY of velocity dispersion, size, and CO luminosity to the 1 K antenna temperature isophote that likely overestimates the GMC masses and our assumption of constant {sup 13}CO abundance over the projected area of each cloud. Owing to the uncertainty of molecular abundances in the envelopes of clouds, the mass surface density of GMCs could be larger than the values derived from our {sup 13}CO measurements. From velocity dispersions derived from the {sup 13}CO data, we find that the coefficient of the cloud structure functions, v{sup 0} = {sigma}{sub v}/R {sup 1/2}, is not constant, as required to satisfy Larson's scaling relationships, but rather systematically varies with the surface density of the cloud as {approx}{sigma}{sup 0.5} as expected for clouds in self-gravitational equilibrium.

  12. Re-Examining Larson's Scaling Relationships in Galactic Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Heyer, Mark; Krawczyk, Coleman; Duval, Julia; Jackson, James M.

    2009-07-01

    The properties of Galactic molecular clouds tabulated by Solomon et al. (SRBY) are re-examined using the Boston University-FCRAO Galactic Ring Survey of 13CO J = 1-0 emission. These new data provide a lower opacity tracer of molecular clouds and improved angular and spectral resolution compared with previous surveys of molecular line emission along the Galactic Plane. We calculate giant molecular cloud (GMC) masses within the SRBY cloud boundaries assuming local thermodynamic equilibrium (LTE) conditions throughout the cloud and a constant H2 to 13CO abundance, while accounting for the variation of the 12C/13C with galactocentric radius. The LTE-derived masses are typically five times smaller than the SRBY virial masses. The corresponding median mass surface density of molecular hydrogen for this sample is 42 M sun pc-2, which is significantly lower than the value derived by SRBY (median 206 M sun pc-2) that has been widely adopted by most models of cloud evolution and star formation. This discrepancy arises from both the extrapolation by SRBY of velocity dispersion, size, and CO luminosity to the 1 K antenna temperature isophote that likely overestimates the GMC masses and our assumption of constant 13CO abundance over the projected area of each cloud. Owing to the uncertainty of molecular abundances in the envelopes of clouds, the mass surface density of GMCs could be larger than the values derived from our 13CO measurements. From velocity dispersions derived from the 13CO data, we find that the coefficient of the cloud structure functions, v ° = σ v /R 1/2, is not constant, as required to satisfy Larson's scaling relationships, but rather systematically varies with the surface density of the cloud as ~Σ0.5 as expected for clouds in self-gravitational equilibrium.

  13. Diversity trends and their ontogenetic basis: an exploration of allometric disparity in rodents.

    PubMed

    Wilson, Laura A B; Sánchez-Villagra, Marcelo R

    2010-04-22

    It has been hypothesized that most morphological evolution occurs by allometric differentiation. Because rodents encapsulate a phenomenal amount of taxonomic diversity and, among several clades, contrasting levels of morphological diversity, they represent an excellent subject to address the question: how variable are allometric patterns during evolution? We investigated the influence of phylogenetic relations and ecological factors on the results of the first quantification of allometric disparity among rodents by exploring allometric space, a multivariate morphospace here derived from, and encapsulating all, the ontogenetic trajectories of 34 rodent species from two parallel phylogenetic radiations. Disparity was quantified using angles between ontogenetic trajectories for different species and clades. We found an overlapping occupation of allometric space by muroid and hystricognath species, revealing both clades possess similar abilities to evolve in different directions of phenotypic space, and anatomical diversity does not act to constrain the labile nature of allometric patterning. Morphological features to enable efficient processing of food serve to group rodents in allometric space, reflecting the importance of convergent morphology, rather than shared evolutionary history, in the generation of allometric patterns. Our results indicate that the conserved level of morphological integration found among primates cannot simply be extended to all mammals. PMID:20018789

  14. The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles.

    PubMed

    Cuff, Andrew R; Sparkes, Emily L; Randau, Marcela; Pierce, Stephanie E; Kitchener, Andrew C; Goswami, Anjali; Hutchinson, John R

    2016-07-01

    The body masses of cats (Mammalia, Carnivora, Felidae) span a ~300-fold range from the smallest to largest species. Despite this range, felid musculoskeletal anatomy remains remarkably conservative, including the maintenance of a crouched limb posture at unusually large sizes. The forelimbs in felids are important for body support and other aspects of locomotion, as well as climbing and prey capture, with the assistance of the vertebral (and hindlimb) muscles. Here, we examine the scaling of the anterior postcranial musculature across felids to assess scaling patterns between different species spanning the range of felid body sizes. The muscle architecture (lengths and masses of the muscle-tendon unit components) for the forelimb, cervical and thoracic muscles was quantified to analyse how the muscles scale with body mass. Our results demonstrate that physiological cross-sectional areas of the forelimb muscles scale positively with increasing body mass (i.e. becoming relatively larger). Many significantly allometric variables pertain to shoulder support, whereas the rest of the limb muscles become relatively weaker in larger felid species. However, when phylogenetic relationships were corrected for, most of these significant relationships disappeared, leaving no significantly allometric muscle metrics. The majority of cervical and thoracic muscle metrics are not significantly allometric, despite there being many allometric skeletal elements in these regions. When forelimb muscle data were considered in isolation or in combination with those of the vertebral muscles in principal components analyses and MANOVAs, there was no significant discrimination among species by either size or locomotory mode. Our results support the inference that larger felid species have relatively weaker anterior postcranial musculature compared with smaller species, due to an absence of significant positive allometry of forelimb or vertebral muscle architecture. This difference in strength

  15. The Mentoring Relationship Challenges Scale: The Impact of Mentoring Stage, Type, and Gender

    ERIC Educational Resources Information Center

    Ensher, Ellen A.; Murphy, Susan E.

    2011-01-01

    The current study investigated the role of relational challenges as reported by 309 proteges in various stages and types of mentoring relationships. The Mentoring Relationship Challenges Scale (MRCS) was newly constructed using the results of an earlier qualitative study (Ensher & Murphy, 2005). The scale measured three factors of relational…

  16. Development of a Behavioral Affective Relationship Scale for Encounter Research.

    ERIC Educational Resources Information Center

    Shadish, William R., Jr.; Zarle, Thomas

    The paper outlines several studies over a two-year period to develop a self-report and observer-rating measure of sensitivity/encounter group outcome. The initial form of the scale was taken from McMillan (1971) who developed a measure of 16 categories of group outcome; McMillan's work indicated the scale had high reliability. Subsequent study…

  17. Technical note: Multiple wavelet coherence for untangling scale-specific and localized multivariate relationships in geosciences

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Si, Bing Cheng

    2016-08-01

    The scale-specific and localized bivariate relationships in geosciences can be revealed using bivariate wavelet coherence. The objective of this study was to develop a multiple wavelet coherence method for examining scale-specific and localized multivariate relationships. Stationary and non-stationary artificial data sets, generated with the response variable as the summation of five predictor variables (cosine waves) with different scales, were used to test the new method. Comparisons were also conducted using existing multivariate methods, including multiple spectral coherence and multivariate empirical mode decomposition (MEMD). Results show that multiple spectral coherence is unable to identify localized multivariate relationships, and underestimates the scale-specific multivariate relationships for non-stationary processes. The MEMD method was able to separate all variables into components at the same set of scales, revealing scale-specific relationships when combined with multiple correlation coefficients, but has the same weakness as multiple spectral coherence. However, multiple wavelet coherences are able to identify scale-specific and localized multivariate relationships, as they are close to 1 at multiple scales and locations corresponding to those of predictor variables. Therefore, multiple wavelet coherence outperforms other common multivariate methods. Multiple wavelet coherence was applied to a real data set and revealed the optimal combination of factors for explaining temporal variation of free water evaporation at the Changwu site in China at multiple scale-location domains. Matlab codes for multiple wavelet coherence were developed and are provided in the Supplement.

  18. Allometric growth in the extant coelacanth lung during ontogenetic development.

    PubMed

    Cupello, Camila; Brito, Paulo M; Herbin, Marc; Meunier, François J; Janvier, Philippe; Dutel, Hugo; Clément, Gaël

    2015-01-01

    Coelacanths are lobe-finned fishes known from the Devonian to Recent that were long considered extinct, until the discovery of two living species in deep marine waters of the Mozambique Channel and Sulawesi. Despite extensive studies, the pulmonary system of extant coelacanths has not been fully investigated. Here we confirm the presence of a lung and discuss its allometric growth in Latimeria chalumnae, based on a unique ontogenetic series. Our results demonstrate the presence of a potentially functional, well-developed lung in the earliest known coelacanth embryo, and its arrested growth at later ontogenetic stages, when the lung is clearly vestigial. The parallel development of a fatty organ for buoyancy control suggests a unique adaptation to deep-water environments. Furthermore, we provide the first evidence for the presence of small, hard, flexible plates around the lung in L. chalumnae, and consider them homologous to the plates of the 'calcified lung' of fossil coelacanths. PMID:26372119

  19. Allometric growth in the extant coelacanth lung during ontogenetic development

    PubMed Central

    Cupello, Camila; Brito, Paulo M.; Herbin, Marc; Meunier, François J; Janvier, Philippe; Dutel, Hugo; Clément, Gaël

    2015-01-01

    Coelacanths are lobe-finned fishes known from the Devonian to Recent that were long considered extinct, until the discovery of two living species in deep marine waters of the Mozambique Channel and Sulawesi. Despite extensive studies, the pulmonary system of extant coelacanths has not been fully investigated. Here we confirm the presence of a lung and discuss its allometric growth in Latimeria chalumnae, based on a unique ontogenetic series. Our results demonstrate the presence of a potentially functional, well-developed lung in the earliest known coelacanth embryo, and its arrested growth at later ontogenetic stages, when the lung is clearly vestigial. The parallel development of a fatty organ for buoyancy control suggests a unique adaptation to deep-water environments. Furthermore, we provide the first evidence for the presence of small, hard, flexible plates around the lung in L. chalumnae, and consider them homologous to the plates of the ‘calcified lung' of fossil coelacanths. PMID:26372119

  20. Complexity Increases Predictability in Allometrically Constrained Food Webs.

    PubMed

    Iles, Alison C; Novak, Mark

    2016-07-01

    All ecosystems are subjected to chronic disturbances, such as harvest, pollution, and climate change. The capacity to forecast how species respond to such press perturbations is limited by our imprecise knowledge of pairwise species interaction strengths and the many direct and indirect pathways along which perturbations can propagate between species. Network complexity (size and connectance) has thereby been seen to limit the predictability of ecological systems. Here we demonstrate a counteracting mechanism in which the influence of indirect effects declines with increasing network complexity when species interactions are governed by universal allometric constraints. With these constraints, network size and connectance interact to produce a skewed distribution of interaction strengths whose skew becomes more pronounced with increasing complexity. Together, the increased prevalence of weak interactions and the increased relative strength and rarity of strong interactions in complex networks limit disturbance propagation and preserve the qualitative predictability of net effects even when pairwise interaction strengths exhibit substantial variation or uncertainty. PMID:27322124

  1. Exploring Undergraduate Student Attitudes toward Persons with Disabilities: Application of the Disability Social Relationship Scale

    ERIC Educational Resources Information Center

    Hergenrather, Kenneth; Rhodes, Scott

    2007-01-01

    The Disability Social Relations Generalized Disability (DSRGD) Scale was used to explore the influence of the social context on attitudes toward persons with disabilities. The DSRGD Scale was based on the Disability Social Relationship (DSR) Scale (Grand, Bernier, & Strohmer, 1982; Strohmer, Grand, & Purcell, 1984). A sample of 1,013 undergraduate…

  2. An Adaptation, Validity and Reliability of the Lifespan Sibling Relationship Scale to the Turkish Adolescents

    ERIC Educational Resources Information Center

    Öz, F. Selda

    2015-01-01

    The purpose of this study is to adapt the Lifespan Sibling Relationship Scale (LSRS) developed by Riggio (2000) to Turkish. The scale with its original form in English consists of 48 items in total. The original scale was translated into Turkish by three instructors who are proficient both in the field and the language. Later, the original and…

  3. Scale-invariant structure of size fluctuations in plants

    NASA Astrophysics Data System (ADS)

    Picoli, S.; Mendes, R. S.; Lenzi, E. K.; Malacarne, L. C.

    2012-03-01

    A wide range of physical and biological systems exhibit complex behaviours characterised by a scale-invariant structure of the fluctuations in their output signals. In the context of plant populations, scaling relationships are typically allometric. In this study, we analysed spatial variation in the size of maize plants (Zea Mays L.) grown in agricultural plots at constant densities and found evidence of scaling in the size fluctuations of plants. The findings indicate that the scaling of the probability distribution of spatial size fluctuation exhibits non-Gaussian behaviour compatible with a Lévy stable process. The scaling relationships were observed for spatial scales spanning three orders of magnitude. These findings should provide additional information for the selection and development of empirically accurate models of pattern formation in plant populations.

  4. Visualizing the Earth and Moon Relationship via Scaled Drawings

    ERIC Educational Resources Information Center

    Fidler, Chuck; Dotger, Sharon

    2009-01-01

    Students' difficulties with accurately conceptualizing the relationships among the Earth, Moon, and Sun are well documented. Any teacher who has seen the film "A Private Universe" (Schneps and Sadler 1988) will remember the challenge the interviewees experienced when trying to explain their understanding of this phenomenon. This paper describes a…

  5. Craniodental features in male Mandrillus may signal size and fitness: an allometric approach.

    PubMed

    Klopp, Emily B

    2012-04-01

    According to a hypothesis in the broader mammalian literature, secondary sexual characteristics that have evolved to signal fitness and size to other conspecifics should exhibit positive allometry across adult males within a species. Here this hypothesis is tested in the genus Mandrillus. The overbuilding of bony features in larger individuals necessitates a functional explanation as bone is metabolically expensive to produce and maintain. Canine size and size of the maxillary ridge are scaled against a body size surrogate in intraspecific samples of male Mandrillus sphinx (mandrills) and Mandrillus leucophaeus (drills). Areal dimensions are weighted more heavily as they represent the size of a feature as it is viewed by individuals. Measures of the maxillary ridge and canine tooth are significantly correlated with the size surrogate and scale with positive allometry in both samples supporting the hypothesis that these features function to advertise a male's body size and fitness to other males competing for mates and potential discerning females. This is the first study in primates to test for intraspecific positive allometric scaling of bony facial features in adult males based on a theory of fitness signaling and sexual selection. PMID:22328467

  6. Fault populations and their relationship to the scaling of surface roughness

    NASA Astrophysics Data System (ADS)

    Pickering, G.; Bull, J. M.; Sanderson, D. J.

    1999-02-01

    The relationship between the scaling properties of faulted geological surfaces and parameters describing the underlying fault population are investigated using simulations of a dip-slip faulted surface. Analysis of multiple simulations of sections through the surface allowed the construction of a statistical relationship between the parameters defining the fault population and the fractal dimension of the surface. The results indicate a direct, if complex, relationship between the fault population and the scaling of the surface roughness. The main determining factor is the displacement distribution, with spacing and dip having only a minor contribution. This relationship is tested against examples from the Moray Firth, Scotland, and the central Indian Ocean.

  7. Scaling relationships and concavity of small valley networks on Mars

    NASA Astrophysics Data System (ADS)

    Penido, Julita C.; Fassett, Caleb I.; Som, Sanjoy M.

    2013-01-01

    Valley networks are widely interpreted as the preserved erosional record of water flowing across the martian surface. The manner in which valley morphometric properties scale with drainage area has been widely examined on Earth. Earlier studies assessing these properties on Mars have suggested that martian valleys are morphometrically distinct from those on Earth. However, these earlier measurements were generally made on large valley systems because of the limited topographic data available. In this study, we determine the scaling properties of valley networks at smaller scales than have been previously assessed, using digital elevation models from the High Resolution Stereo Camera (HRSC). We find a Hack's law exponent of 0.74, larger than on Earth, and our measurements also reveal that individual small valleys have concave up, concave down, and quasi-linear longitudinal profiles, consistent with earlier studies of dissected terrain on Mars. However, for many valleys, widths are observed to increase downstream similarly to how they scale in terrestrial channels. The similarities and differences between valley networks on Mars and Earth are consistent with the idea that valleys on Mars are comparatively immature, and precipitation was a likely mechanism for delivering water to these networks.

  8. FIELD SAMPLING IN ESTUARIES: THE RELATIONSHIP OF SCALE TO VARIABILITY

    EPA Science Inventory

    The spatial/temporal scaling problem (i.e., fitting a given research question to the dimensions of variability of the study area) is particularly pronounced in highly variable systems such as estuaries. Long-term, multidisciplinary studies in the Apalachicola Bay system were used...

  9. Technical Basis of Scaling Relationships for the Pretreatment Engineering Platform

    SciTech Connect

    Kuhn, William L.; Arm, Stuart T.; Huckaby, James L.; Kurath, Dean E.; Rassat, Scot D.

    2008-07-15

    Pacific Northwest National Laboratory has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities. The Pretreatment Engineering Platform (PEP) is being designed and constructed as part of a plan to respond to an issue raised by the WTP External Flowsheet Review Team (EFRT) entitled “Undemonstrated Leaching Processes” and numbered M12. The PEP replicates the WTP leaching process using prototypic equipment and control strategies. The approach for scaling PEP performance data to predict WTP performance is critical to the successful resolution of the EFRT issue. This report describes the recommended PEP scaling approach, PEP data interpretation and provides recommendations on test conduct and data requirements.

  10. Negative scaling relationship between molecular diversity and resource abundances

    NASA Astrophysics Data System (ADS)

    Kamimura, Atsushi; Kaneko, Kunihiko

    2016-06-01

    Cell reproduction involves replication of diverse molecule species, in contrast to a simple replication system with fewer components. To address this question of diversity, we study theoretically a cell system with catalytic reaction dynamics that grows by uptake of environmental resources. It is shown that limited resources lead to increased diversity of components within the system, and the number of coexisting species increases with a negative power of the resource uptake. The relationship is explained from the optimum growth speed of the cell, determined by a tradeoff between the utility of diverse resources and the concentration onto fewer components to increase the reaction rate.

  11. An allometric study of lung morphology during development in the Australian pelican, Pelicanus conspicillatus, from embryo to adult

    PubMed Central

    Runciman, S; Seymour, RS; Baudinette, RV; Pearson, JT

    2005-01-01

    Pelicans produce altricial chicks that develop into some of the largest birds capable of sustained flight. We traced pulmonary morphological development in the Australian pelican, Pelicanus conspicillatus, from third trimester embryos to adults. We described growth and development with allometric relationships between lung components and body mass or lung volume, according to the equation y = axb. Pelican lung volume increased faster than body mass (b = 1.07). Relative to lung volume, the airways and vascular spaces increased allometrically (b > 1) in embryos, but isometrically (b ≈ 1) after hatching. Parabronchial mantle volume decreased (b < 1) prior to hatching and increased isometrically thereafter. Surface area of air capillaries, blood capillaries and the blood–gas barrier increased relative to lung volume (b > 0.67) before and after hatching. Barrier thickness decreased before hatching, remained constant in juveniles and decreased by adulthood. The anatomical diffusing capacity significantly increased before hatching (b = 4.44) and after hatching (b = 1.26). Although altricial pelicans developed pulmonary complexity later than precocial turkeys, the volume-specific characteristics were similar. However, lungs of volant adult pelicans became significantly larger, with a greater capacity for gas exchange, than lungs of terrestrial turkeys. Exchange characteristics of growing pelican lungs were inferior to those of adult birds of 26 other species, but converged with them at maturity. PMID:16191165

  12. Left Ventricular Hypertrophy: An allometric comparative analysis of different ECG markers

    NASA Astrophysics Data System (ADS)

    Bonomini, M. P.; Ingallina, F.; Barone, V.; Valentinuzzi, M. E.; Arini, P. D.

    2011-12-01

    Allometry, in general biology, measures the relative growth of a part in relation to the whole living organism. Left ventricular hypertrophy (LVH) is the heart adaptation to excessive load (systolic or diastolic). The increase in left ventricular mass leads to an increase in the electrocardiographic voltages. Based on clinical data, we compared the allometric behavior of three different ECG markers of LVH. To do this, the allometric fit AECG = δ + β (VM) relating left ventricular mass (estimated from ecocardiographic data) and ECG amplitudes (expressed as the Cornell-Voltage, Sokolow and the ECG overall voltage indexes) were compared. Besides, sensitivity and specifity for each index were analyzed. The more sensitive the ECG criteria, the better the allometric fit. In conclusion: The allometric paradigm should be regarded as the way to design new and more sensitive ECG-based LVH markers.

  13. Scale dependence of the directional relationships between coupled time series

    NASA Astrophysics Data System (ADS)

    Shirazi, Amir Hossein; Aghamohammadi, Cina; Anvari, Mehrnaz; Bahraminasab, Alireza; Rahimi Tabar, M. Reza; Peinke, Joachim; Sahimi, Muhammad; Marsili, Matteo

    2013-02-01

    Using the cross-correlation of the wavelet transformation, we propose a general method of studying the scale dependence of the direction of coupling for coupled time series. The method is first demonstrated by applying it to coupled van der Pol forced oscillators and coupled nonlinear stochastic equations. We then apply the method to the analysis of the log-return time series of the stock values of the IBM and General Electric (GE) companies. Our analysis indicates that, on average, IBM stocks react earlier to possible common sector price movements than those of GE.

  14. Scale and hierarchical relationships when incorporating observed data into fish models

    EPA Science Inventory

    Identifying correlations between environmental variables and fish presence or density is usually the main focus of efforts to model fish-habitat relationships. These relationships, however, can be confounded by scale and hierarchical effects. In particular the strength of fish –...

  15. The Development of a Scale to Explore the Multidimensional Components of Good Student-Teacher Relationships

    ERIC Educational Resources Information Center

    Wilkins, Julia

    2014-01-01

    The Student-Teacher Relationship Survey: Student Version was developed and assessed for factor structure using principal components analysis. No instruments measuring students' perceptions of student-teacher relationships have been developed for high school students, and scales that measure related constructs tend to view good student-teacher…

  16. Assessing Social Support, Companionship, and Distress: NIH Toolbox Adult Social Relationship Scales

    PubMed Central

    Cyranowski, Jill M.; Zill, Nicholas; Bode, Rita; Butt, Zeeshan; Kelly, Morgen A. R.; Pilkonis, Paul A.; Salsman, John M.; Cella, David

    2013-01-01

    Objective The quality of our daily social interactions – including perceptions of support, feelings of loneliness, and distress stemming from negative social exchanges – influence physical health and well-being. Despite the importance of social relationships, brief yet precise, unidimensional scales that assess key aspects of social relationship quality are lacking. As part of the NIH Toolbox for the Assessment of Neurological and Behavioral Function, we developed brief self-report scales designed to assess aspects of social support, companionship, and social distress across age cohorts. This report details the development and psychometric testing of the adult NIH Toolbox Social Relationship scales. Methods Social relationship concepts were selected, and item sets were developed and revised based on expert feedback and literature review. Items were then tested across a community-dwelling U.S. internet panel sample of adults aged 18 and above (N=692) using traditional (classic) psychometric methods and item response theory (IRT) approaches to identify items for inclusion in 5–8 item unidimensional scales. Finally, concurrent validity of the newly-developed scales was evaluated with respect to their inter-relationships with classic social relationship validation instruments. Results Results provide support for the internal reliability and concurrent validity of resulting self-report scales assessing Emotional Support, Instrumental Support, Friendship, Loneliness, Perceived Rejection, and Perceived Hostility. Conclusion These brief social relationship scales provide the pragmatic utility and enhanced precision needed to promote future epidemiological and social neuroscience research on the impact of social relationships on physical and emotional health outcomes. PMID:23437856

  17. Applying the Nominal Response Model within a Longitudinal Framework to Construct the Positive Family Relationships Scale

    ERIC Educational Resources Information Center

    Preston, Kathleen Suzanne Johnson; Parral, Skye N.; Gottfried, Allen W.; Oliver, Pamella H.; Gottfried, Adele Eskeles; Ibrahim, Sirena M.; Delany, Danielle

    2015-01-01

    A psychometric analysis was conducted using the nominal response model under the item response theory framework to construct the Positive Family Relationships scale. Using data from the Fullerton Longitudinal Study, this scale was constructed within a long-term longitudinal framework spanning middle childhood through adolescence. Items tapping…

  18. Evaluating Empirical Relationships among Prediction, Measurement, and Scaling Invariance. Research Report. ETS RR-11-06

    ERIC Educational Resources Information Center

    Moses, Tim

    2011-01-01

    The purpose of this study was to consider the relationships of prediction, measurement, and scaling invariance when these invariances were simultaneously evaluated in psychometric test data. An approach was developed to evaluate prediction, measurement, and scaling invariance based on linear and nonlinear prediction, measurement, and scaling…

  19. Encountering unexpected difficult airway: relationship with the intubation difficulty scale

    PubMed Central

    Koh, Wonuk; Kim, Hajung; Kim, Kyongsun; Ro, Young-Jin

    2016-01-01

    Background An unexpected difficult intubation can be very challenging and if it is not managed properly, it may expose the encountered patient to significant risks. The intubation difficulty scale (IDS) has been used as a validated method to evaluate a global degree of intubation difficulty. The aims of this study were to evaluate the prevalence and characteristics of unexpected difficult intubation using the IDS. Methods We retrospectively reviewed 951 patients undergoing elective surgery in a single medical center. Patients expected to have a difficult intubation or who had history of difficult intubation were excluded. Each patient was assessed by the IDS scoring system with seven variables. Total prevalence of difficult intubation and the contributing individual factors were further analyzed. Results For the 951 patients, the difficult intubation cases presenting IDS > 5 was 5.8% of total cases (n = 55). The prevalence of Cormack-Lehane Grade 3 or 4 was 16.2% (n = 154). Most of the difficult intubation cases were managed by simple additional maneuvers and techniques such as stylet application, additional lifting force and laryngeal pressure. Conclusions Unexpected difficult airway was present in 5.8% of patients and most was managed effectively. Among the components of IDS, the Cormack-Lehane grade was most sensitive for predicting difficult intubation. PMID:27274369

  20. A general allometric and life-history model for cellular differentiation in the transition to multicellularity.

    PubMed

    Solari, Cristian A; Kessler, John O; Goldstein, Raymond E

    2013-03-01

    The transition from unicellular, to colonial, to larger multicellular organisms has benefits, costs, and requirements. Here we present a model inspired by the volvocine green algae that explains the dynamics involved in the unicellular-multicellular transition using life-history theory and allometry. We model the two fitness components (fecundity and viability) and compare the fitness of hypothetical colonies of different sizes with varying degrees of cellular differentiation to understand the general principles that underlie the evolution of multicellularity. We argue that germ-soma separation may have evolved to counteract the increasing costs and requirements of larger multicellular colonies. The model shows that the cost of investing in soma decreases with size. For lineages such as the Volvocales, as reproduction costs increase with size for undifferentiated colonies, soma specialization benefits the colony indirectly by decreasing such costs and directly by helping reproductive cells acquire resources for their metabolic needs. Germ specialization is favored once soma evolves and takes care of vegetative functions. To illustrate the model, we use some allometric relationships measured in Volvocales. Our analysis shows that the cost of reproducing an increasingly larger group has likely played an important role in the transition to multicellularity and cellular differentiation. PMID:23448886

  1. Quantifying the curvilinear metabolic scaling in mammals.

    PubMed

    Packard, Gary C

    2015-10-01

    A perplexing problem confronting students of metabolic allometry concerns the convex curvature that seemingly occurs in log-log plots of basal metabolic rate (BMR) vs. body mass in mammals. This putative curvilinearity has typically been interpreted in the context of a simple power function, Y=a*Xb, on the arithmetic scale, with the allometric exponent, b, supposedly increasing steadily as a dependent function of body size. The relationship can be quantified in arithmetic domain by exponentiating a quadratic equation fitted to logarithmic transformations of the original data, but the resulting model is not in the form of a power function and it is unlikely to describe accurately the pattern in the original distribution. I therefore re-examined a dataset for 636 species of mammal and discovered that the relationship between BMR and body mass is well-described by a power function with an explicit, non-zero intercept and lognormal, heteroscedastic error. The model has an invariant allometric exponent of 0.75, so the appearance in prior investigations of a steadily increasing exponent probably was an aberration resulting from undue reliance on logarithmic transformations to estimate statistical models in arithmetic domain. Theoretical constructs relating BMR to body mass in mammals may need to be modified to accommodate a positive intercept in the statistical model, but they do not need to be revised, or rejected, at present time on grounds that the allometric exponent varies with body size. New data from planned experiments will be needed to confirm any hypothesis based on data currently available. PMID:26173580

  2. Revisiting spatial scale in the productivity-species richness relationship: fundamental issues and global change implications.

    PubMed

    McBride, Paul D; Cusens, Jarrod; Gillman, Len N

    2014-01-01

    The relationship between net primary productivity (NPP) and species richness has been the subject of long-running debate. A changing climate gives added impetus to resolving this debate, as it becomes increasingly necessary to predict biodiversity responses that might arise from shifts in productivity or its climatic correlates. It has become increasingly clear that at small scales productivity-species richness relationships (PSRs) are variable, while at macro scales relationships are typically positive. We demonstrate the importance of explicitly considering scale in discussions on PSRs even at large scales by showing that distinct patterns emerge in a global dataset of terrestrial ecoregions when ecoregions are binned into size classes. At all sizes, PSRs in ecoregions are positive, but the strength of the PSR scales positively with ecoregion size. In small ecoregions (10(3)-10(4) km(2)), factors correlating with productivity play only a minor role in species richness patterns, while in large ecoregions (>10(5) km(2)), NPP modelled from remotely sensed data is able to explain most of the variation in species richness. Better understanding the effects of scale on PSRs contributes to the debate on the relationship between species richness and productivity, which in turn allows us to better predict how both long- and short-term biodiversity patterns and ecosystem functioning might be altered under global change scenarios. This gives focus on future research to clarify causal pathways between species richness and productivity with appropriate attention to scale as an important focusing element. PMID:25249265

  3. Scaling relationships for soil formation and edaphic controls on vegetation growth

    NASA Astrophysics Data System (ADS)

    Hunt, A. G.; Ghanbarian, B.

    2015-12-01

    Critical path analysis (CPA) is suited to calculating the hydraulic conductivity, K, of heterogeneous porous media by quantifying of paths of least resistance. Whenever CPA could be used to calculate K, advective transport scaling relationships from percolation theory should describe solute transport. Two solute transport relationships are applied to predict soil development and edaphic constraints on natural vegetation growth. These results use known exponents from percolation theory and known subsurface flow velocities. The typical flow velocity itself constrains optimal growth rates of cultivars. The percolation scaling relationship constraining vegetation growth is shown to be in accord with data over time scales from hours to 100,000 years, including over a dozen studies (and two models) of tree growth. The scaling function for soil development explains time scales for formation of soils from years to hundreds of millions of years. Data on soil development comes from 23 different studies. The key unification is the common origin of the time and space coordinates for all three relationships in the time of transport through a single pore of roughly micron size at a typical subsurface pore-scale flow velocity. The distinction in evolving time scales is primarily a result of the hierarchical nature of vascular plant root systems, which speed up nutrient access relative to physical transport rates in the soil. The results help explain reduction in forest productivity with age, diminishing soil production with time, and the temporal distinction between the relevance of chemical and biological processes in soils to the global carbon cycle.

  4. PROMIS Pediatric Peer Relationships Scale: Development of a Peer Relationships Item Bank as Part of Social Health Measurement

    PubMed Central

    DeWalt, Darren A.; Thissen, David; Stucky, Brian D.; Langer, Michelle M.; DeWitt, Esi Morgan; Irwin, Debra E.; Lai, Jin-Shei; Yeatts, Karin B.; Gross, Heather E.; Taylor, Olivia; Varni, James W.

    2013-01-01

    Objective This study’s objective was to develop a measure of social health using item response theory as part of the Patient Reported Outcomes Measurement Information System (PROMIS). Methods After candidate items were generated from review of prior literature, focus groups, expert input, and cognitive interviews, items were administered to youth aged 8–17 as part of the PROMIS pediatric large scale testing. Exploratory and confirmatory factor analyses were used to assess dimensionality and to identify instances of local dependence. Items that met the unidimensionality criteria were subsequently calibrated using Samejima’s Graded Response Model. Differential item functioning was examined by gender and age. Results The sample included 3,048 youth who completed the questionnaire (51.8% female, 60% white, and 22.7% with chronic illness). The initial conceptualization of social function and sociability did not yield unidimensional item banks. Rather, factor analysis revealed dimensions contrasting peer relationships and adult relationships. The analysis also identified dimensions formed by responses to positively versus negatively worded items. The resulting 15-item bank measures quality of peer relationships and has strong psychometric characteristics as a full bank or an 8-item short form. Conclusions The PROMIS pediatric peer relationships scale demonstrates good psychometric characteristics and addresses an important aspect of child health. PMID:23772887

  5. [Development of scales of relationships between grandchildren in adolescence and grandparents].

    PubMed

    Tabata, O; Hoshino, K; Sato, A; Tsuboi, S; Hashimoto, T; Endo, H

    1996-12-01

    The purposes of this study are (1) to make scales of relationships between grandchildren in adolescence and grandparents, and (2) to clarify functions of grandparents perceived by grandchildren and functions of grandchildren perceived by grandparents. Subjects were 517 students in junior high schools, high schools and universities (mean of age: 17 years old), and 107 elderly persons at home (mean of age: 73 years old). As a result, factorial validity and reliability of the scales were confirmed. We found the functions of "daily emotional support", "acceptance of existence", "time perspectives", and "succession of generations" in both the grandchildren scale and the grandparents scale. Additionally we identified the function of "instrumental informational support" in the grandparents scale. The fact that the functions of "time perspectives", and "succession of generations" were found in two groups suggested the facilitation of mutual development between the generations. In addition, the function of "acceptance of existence" suggested possibilities of genuinely supportive relationships. PMID:9121010

  6. A predictive nondestructive model for the covariation of tree height, diameter, and stem volume scaling relationships.

    PubMed

    Zhang, Zhongrui; Zhong, Quanlin; Niklas, Karl J; Cai, Liang; Yang, Yusheng; Cheng, Dongliang

    2016-01-01

    Metabolic scaling theory (MST) posits that the scaling exponents among plant height H, diameter D, and biomass M will covary across phyletically diverse species. However, the relationships between scaling exponents and normalization constants remain unclear. Therefore, we developed a predictive model for the covariation of H, D, and stem volume V scaling relationships and used data from Chinese fir (Cunninghamia lanceolata) in Jiangxi province, China to test it. As predicted by the model and supported by the data, normalization constants are positively correlated with their associated scaling exponents for D vs. V and H vs. V, whereas normalization constants are negatively correlated with the scaling exponents of H vs. D. The prediction model also yielded reliable estimations of V (mean absolute percentage error = 10.5 ± 0.32 SE across 12 model calibrated sites). These results (1) support a totally new covariation scaling model, (2) indicate that differences in stem volume scaling relationships at the intra-specific level are driven by anatomical or ecophysiological responses to site quality and/or management practices, and (3) provide an accurate non-destructive method for predicting Chinese fir stem volume. PMID:27553773

  7. A predictive nondestructive model for the covariation of tree height, diameter, and stem volume scaling relationships

    PubMed Central

    Zhang, Zhongrui; Zhong, Quanlin; Niklas, Karl J.; Cai, Liang; Yang, Yusheng; Cheng, Dongliang

    2016-01-01

    Metabolic scaling theory (MST) posits that the scaling exponents among plant height H, diameter D, and biomass M will covary across phyletically diverse species. However, the relationships between scaling exponents and normalization constants remain unclear. Therefore, we developed a predictive model for the covariation of H, D, and stem volume V scaling relationships and used data from Chinese fir (Cunninghamia lanceolata) in Jiangxi province, China to test it. As predicted by the model and supported by the data, normalization constants are positively correlated with their associated scaling exponents for D vs. V and H vs. V, whereas normalization constants are negatively correlated with the scaling exponents of H vs. D. The prediction model also yielded reliable estimations of V (mean absolute percentage error = 10.5 ± 0.32 SE across 12 model calibrated sites). These results (1) support a totally new covariation scaling model, (2) indicate that differences in stem volume scaling relationships at the intra-specific level are driven by anatomical or ecophysiological responses to site quality and/or management practices, and (3) provide an accurate non-destructive method for predicting Chinese fir stem volume. PMID:27553773

  8. Approaching a universal scaling relationship between fracture stiffness and fluid flow

    NASA Astrophysics Data System (ADS)

    Pyrak-Nolte, Laura J.; Nolte, David D.

    2016-02-01

    A goal of subsurface geophysical monitoring is the detection and characterization of fracture alterations that affect the hydraulic integrity of a site. Achievement of this goal requires a link between the mechanical and hydraulic properties of a fracture. Here we present a scaling relationship between fluid flow and fracture-specific stiffness that approaches universality. Fracture-specific stiffness is a mechanical property dependent on fracture geometry that can be monitored remotely using seismic techniques. A Monte Carlo numerical approach demonstrates that a scaling relationship exists between flow and stiffness for fractures with strongly correlated aperture distributions, and continues to hold for fractures deformed by applied stress and by chemical erosion as well. This new scaling relationship provides a foundation for simulating changes in fracture behaviour as a function of stress or depth in the Earth and will aid risk assessment of the hydraulic integrity of subsurface sites.

  9. Approaching a universal scaling relationship between fracture stiffness and fluid flow.

    PubMed

    Pyrak-Nolte, Laura J; Nolte, David D

    2016-01-01

    A goal of subsurface geophysical monitoring is the detection and characterization of fracture alterations that affect the hydraulic integrity of a site. Achievement of this goal requires a link between the mechanical and hydraulic properties of a fracture. Here we present a scaling relationship between fluid flow and fracture-specific stiffness that approaches universality. Fracture-specific stiffness is a mechanical property dependent on fracture geometry that can be monitored remotely using seismic techniques. A Monte Carlo numerical approach demonstrates that a scaling relationship exists between flow and stiffness for fractures with strongly correlated aperture distributions, and continues to hold for fractures deformed by applied stress and by chemical erosion as well. This new scaling relationship provides a foundation for simulating changes in fracture behaviour as a function of stress or depth in the Earth and will aid risk assessment of the hydraulic integrity of subsurface sites. PMID:26868649

  10. Approaching a universal scaling relationship between fracture stiffness and fluid flow

    PubMed Central

    Pyrak-Nolte, Laura J.; Nolte, David D.

    2016-01-01

    A goal of subsurface geophysical monitoring is the detection and characterization of fracture alterations that affect the hydraulic integrity of a site. Achievement of this goal requires a link between the mechanical and hydraulic properties of a fracture. Here we present a scaling relationship between fluid flow and fracture-specific stiffness that approaches universality. Fracture-specific stiffness is a mechanical property dependent on fracture geometry that can be monitored remotely using seismic techniques. A Monte Carlo numerical approach demonstrates that a scaling relationship exists between flow and stiffness for fractures with strongly correlated aperture distributions, and continues to hold for fractures deformed by applied stress and by chemical erosion as well. This new scaling relationship provides a foundation for simulating changes in fracture behaviour as a function of stress or depth in the Earth and will aid risk assessment of the hydraulic integrity of subsurface sites. PMID:26868649

  11. Theoretical and empirical scale dependency of Z-R relationships: Evidence, impacts, and correction

    NASA Astrophysics Data System (ADS)

    Verrier, Sébastien; Barthès, Laurent; Mallet, Cécile

    2013-07-01

    Estimation of rainfall intensities from radar measurements relies to a large extent on power-laws relationships between rain rates R and radar reflectivities Z, i.e., Z = a*R^b. These relationships are generally applied unawarely of the scale, which is questionable since the nonlinearity of these relations could lead to undesirable discrepancies when combined with scale aggregation. Since the parameters (a,b) are expectedly related with drop size distribution (DSD) properties, they are often derived at disdrometer scale, not at radar scale, which could lead to errors at the latter. We propose to investigate the statistical behavior of Z-R relationships across scales both on theoretical and empirical sides. Theoretically, it is shown that claimed multifractal properties of rainfall processes could constrain the parameters (a,b) such that the exponent b would be scale independent but the prefactor a would be growing as a (slow) power law of time or space scale. In the empirical part (which may be read independently of theoretical considerations), high-resolution disdrometer (Dual-Beam Spectropluviometer) data of rain rates and reflectivity factors are considered at various integration times comprised in the range 15 s - 64 min. A variety of regression techniques is applied on Z-R scatterplots at all these time scales, establishing empirical evidence of a behavior coherent with theoretical considerations: a grows as a 0.1 power law of scale while b decreases more slightly. The properties of a are suggested to be closely linked to inhomogeneities in the DSDs since extensions of Z-R relationships involving (here, strongly nonconstant) normalization parameters of the DSDs seem to be more robust across scales. The scale dependence of simple Z = a*R^b relationships is advocated to be a possible source of overestimation of rainfall intensities or accumulations. Several ways for correcting such scaling biases (which can reach >15-20% in terms of relative error) are suggested

  12. Scaling relationships among drivers of aquatic respiration from the smallest to the largest freshwater ecosystems

    USGS Publications Warehouse

    Hall, Ed K; Schoolmaster, Donald; Amado, A.M; Stets, Edward G.; Lennon, J.T.; Domaine, L.; Cotner, J.B.

    2016-01-01

    To address how various environmental parameters control or constrain planktonic respiration (PR), we used geometric scaling relationships and established biological scaling laws to derive quantitative predictions for the relationships among key drivers of PR. We then used empirical measurements of PR and environmental (soluble reactive phosphate [SRP], carbon [DOC], chlorophyll a [Chl-a)], and temperature) and landscape parameters (lake area [LA] and watershed area [WA]) from a set of 44 lakes that varied in size and trophic status to test our hypotheses. We found that landscape-level processes affected PR through direct effects on DOC and temperature and indirectly via SRP. In accordance with predictions made from known relationships and scaling laws, scale coefficients (the parameter that describes the shape of a relationship between 2 variables) were found to be negative and have an absolute value 1, others <1). We also found evidence of a significant relationship between temperature and SRP. Because our dataset included measurements of respiration from small pond catchments to the largest body of freshwater on the planet, Lake Superior, these findings should be applicable to controls of PR for the great majority of temperate aquatic ecosystems.

  13. Using tank 107-AN caustic addition for confirmation of mixing scale relationship

    SciTech Connect

    Chang, S.C.

    1995-05-01

    A subscale jet mixing program was carried out in two scale tanks to extend the basis of previous subscale tests to include in-tank geometry associated with tank AN-107. The laboratory data will be correlated with the data to be collected in the upcoming tank AN-107 mixing and caustic addition test. The objective is to verify the scaling relationship used in the MWTF mixer design.

  14. Scaling of the mandible in squirrels.

    PubMed

    Velhagen, W A; Roth, V L

    1997-05-01

    We compared the shape of the mandible among New World tree squirrels and selected outgroup taxa using linear measurements and areas defined by the median axis and conventional anatomical landmarks. We modified the median axis technique to define novel measurements, which proved complementary to those obtained from conventional landmarks. Allometric analyses showed that the scaling of the mandible among the New World tree squirrels is generally isometric (as has been observed in other groups of mammals), but diverges from isometry in a tendency in smaller animals for the masseteric ridge to be displaced anteriorly, the condylar process and posterior portion of the ascending ramus to be relatively elongated, and the coronoid process to be shortened. Allometric analyses also revealed the ways and extent that outgrowth taxa deviated from the scaling pattern observed for the New World tree squirrels. A flying squirrel (subfamily Pteromyinae), a moderate-sized callosciurine squirrel, and three species of pygmy tree squirrels from Asia and Africa show mandibular proportions very similar to those predicted for New World tree squirrels of corresponding size. Ground squirrels (tribe Marmotini) and successively more distant relatives such as Aplodontia, two myomorph rodents, and a rabbit show greater differences from the New World tree squirrels in their mandibular proportions. Combining the use of median-axis and conventional measurements makes it possible to examine changing relationships between locations of anatomically homologous landmarks and the geometry of the form. PMID:9097464

  15. Relationships between rating scales, question stem wording, and community responses to railway noise

    NASA Astrophysics Data System (ADS)

    Sato, Tetsumi; Yano, Takashi; Morihara, Takashi; Masden, Kirk

    2004-10-01

    Two series of social surveys on community responses to railway noise were carried out in Japan to evaluate the relationships between two verbal scales and a numeric scale, and those among four base descriptors. In the first survey, two types of questionnaires were prepared in which a 0-10- point numeric scale was used in combination with either a four-point or a five-point verbal scale. The key questions concerned annoyance, activity disturbance and related effects caused by railway noise. Community responses were compared on the basis of the dose-response relationships. Regarding the percentages of respondents who answered, "highly annoyed," it was found that there were no systematic differences between the two verbal scales. It was also found that the extent of noise annoyance rated on the four-point or five-point verbal scale corresponded with that rated on the 11-point numeric scale by percentages of scale steps. In the second survey, four types of questionnaires were prepared, each using one of the four base descriptors. Community responses to general noise annoyance among the four base descriptors were compared. No systematic differences were found among the four base descriptors.

  16. Regional processes in mangrove ecosystems: Spatial scaling relationships, biomass, and turnover rates following catastrophic disturbance

    USGS Publications Warehouse

    Ward, G.A.; Smith, T. J., III; Whelan, K.R.T.; Doyle, T.W.

    2006-01-01

    Physiological processes and local-scale structural dynamics of mangroves are relatively well studied. Regional-scale processes, however, are not as well understood. Here we provide long-term data on trends in structure and forest turnover at a large scale, following hurricane damage in mangrove ecosystems of South Florida, U.S.A. Twelve mangrove vegetation plots were monitored at periodic intervals, between October 1992 and March 2005. Mangrove forests of this region are defined by a -1.5 scaling relationship between mean stem diameter and stem density, mirroring self-thinning theory for mono-specific stands. This relationship is reflected in tree size frequency scaling exponents which, through time, have exhibited trends toward a community average that is indicative of full spatial resource utilization. These trends, together with an asymptotic standing biomass accumulation, indicate that coastal mangrove ecosystems do adhere to size-structured organizing principles as described for upland tree communities. Regenerative dynamics are different between areas inside and outside of the primary wind-path of Hurricane Andrew which occurred in 1992. Forest dynamic turnover rates, however, are steady through time. This suggests that ecological, more-so than structural factors, control forest productivity. In agreement, the relative mean rate of biomass growth exhibits an inverse relationship with the seasonal range of porewater salinities. The ecosystem average in forest scaling relationships may provide a useful investigative tool of mangrove community biomass relationships, as well as offer a robust indicator of general ecosystem health for use in mangrove forest ecosystem management and restoration. ?? Springer 2006.

  17. Relationships between an invasive crab, habitat availability and intertidal community structure at biogeographic scales.

    PubMed

    Gribben, Paul E; Simpson, Michael; Wright, Jeffrey T

    2015-09-01

    At local scales, habitat availability influences interactions between native and invasive species. Habitat availability may also predict patterns in native communities and invasive species at biogeographic scales when both native and invasive species have specific habitat requirements. The New Zealand porcelain crab, Petrolisthes elongatus, has invaded intertidal rocky shores around Tasmania, Australia, where it is found in high densities (>1800 m(2)) under rocks. A hierarchical sampling approach was used to investigate 1) the relationship between habitat availability (rock cover) and the biomass and abundance of P. elongatus, and 2) the relationship between P. elongatus biomass and native communities at local and regional scales. Invertebrate communities and habitat availability were sampled at multiple sites in the north and south regions of Tasmania. P. elongatus biomass and abundance were positively correlated with rock cover and patterns were consistent at the biogeographic scale (between regions). P. elongatus biomass was positively correlated with native species richness, biomass and abundance highlighting their co-dependence on rock cover. However, multivariate analyses indicated a different native community structure with increasing P. elongatus biomass. Flat, strongly adhering gastropods (chitons and limpets) were positively correlated with P. elongatus biomass, whereas mobile gastropods and crabs were negatively correlated with P. elongatus biomass. Despite local scale variation, there were clear consistent relationships between habitat-availability and the biomass of P. elongatus, and between native communities and the biomass of P. elongatus suggesting that the relationships between native and invasive species may be predictable at large spatial scales. Moreover, the strong relationships between P. elongatus biomass and changes in native community structure suggest a greater understanding of its impact is needed so that appropriate

  18. Density-body mass relationships: Inconsistent intercontinental patterns among termite feeding-groups

    NASA Astrophysics Data System (ADS)

    Dahlsjö, Cecilia A. L.; Parr, Catherine L.; Malhi, Yadvinder; Meir, Patrick; Rahman, Homathevi; Eggleton, Paul

    2015-02-01

    Allometric relationships are useful for estimating and understanding resource distribution in assemblages with species of different masses. Damuth's law states that body mass scales with population density as M-0.75, where M is body mass and -0.75 is the slope. In this study we used Damuth's law (M-0.75) as a null hypothesis to examine the relationship between body mass and population density for termite feeding-groups in three different countries and regions (Cameroon, West Africa; Peru South America; and Malaysia SE Asia). We found that none of the feeding-groups had a relationship where M-0.75 while the data suggested that population density-body mass relationships for true soil-feeding termites in Cameroon (M2.7) and wood-feeding termites in Peru (M1.5) were significantly different from the expected values given by Damuth's law. The dominance of large-bodied true soil-feeding termites in Cameroon and the absence of fungus-growing termites from Peru suggest that these allometric patterns are due to heterogeneities in termite biogeographical evolution. Additionally, as these feeding-groups have higher population density than expected by their body masses it may be suggested that they also have a higher energy throughput than expected. The results presented here may be used to gain further understanding of resource distribution among termite feeding-groups across regions and an insight into the importance of evolutionary history and biogeography on allometric patterns. Further understanding of population density-body mass relationships in termite feeding-groups may also improve understanding of the role these feeding-groups play in ecosystem processes in different regions.

  19. Environmental Conditions Influence Allometric Patterns in the Blow Fly, Chrysomya albiceps

    PubMed Central

    Horenstein, M Battán; Peretti, Av

    2011-01-01

    The objective of this research was to study variations in allometry of body characters in females and males of two populations of blow flies, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), under different environmental conditions to establish patterns of morphological variation. Body size of both males and females in the experimental population was significantly higher than in the individuals of the natural population, indicating an important influence of food on body size. All genitalic and non-genitalic characters in males and females of the two populations showed a trend towards negative allometry rather than isometry. Allometric patterns were modified in both sexes and between populations. The data show generally larger allometric slopes in females than in males. We confirmed that the environmental conditions have an important effect on allometric patterns and body size. PMID:22224467

  20. Dyadic Relationship Scale: A Measure of the Impact of the Provision and Receipt of Family Care

    ERIC Educational Resources Information Center

    Sebern, Margaret D.; Whitlatch, Carol J.

    2007-01-01

    Purpose: This study evaluated the psychometric properties of the Dyadic Relationship Scale (DRS), which measures negative and positive dyadic interactions from the perspective of both the patient and the family caregiver. An important aspect of evaluating the DRS was that it be statistically sound and meaningful for both members of the dyad.…

  1. Assessment of Romantic Perfectionism: Psychometric Properties of the Romantic Relationship Perfectionism Scale

    ERIC Educational Resources Information Center

    Matte, Melody; Lafontaine, Marie-France

    2012-01-01

    The objective of the present study was to provide validity evidence for the scores from the Romantic Relationship Perfectionism Scale. Results indicate a two-factor structure, adequate reliability, and overall good convergent, concurrent, discriminant, and incremental validity evidence. The strengths and limitations of this measure are discussed.…

  2. Examining Factorial Validity and Measurement Invariance of the Student-Teacher Relationship Scale

    ERIC Educational Resources Information Center

    Webb, Mi-young L.; Neuharth-Pritchett, Stacey

    2011-01-01

    The purposes of this study were to (a) test the hypothesized factor structure of the Student-Teacher Relationship Scale (STRS; Pianta, 2001) for 308 African American (AA) and European American (EA) children using confirmatory factor analysis (CFA) and (b) examine the measurement invariance of the factor structure across AA and EA children. CFA of…

  3. Concurrent Validity of the Adult Attachment Scale and the Adolescent Relationship Questionnaire.

    ERIC Educational Resources Information Center

    Domingo, Meera; Chambliss, Catherine

    The Adult Attachment Scale (AAS) (N. Collins and S. Read, 1996) and the Adolescent Relationship Questionnaire (ARQ) (E. Scharfe and K. Bartholomew, 1995) widely used self-assessment measures of attachment behavior. This study investigated the validity of these two measures by administering them concurrently to 117 introductory psychology college…

  4. Assessing Disharmony and Disaffection in Intimate Relationships: Revision of the Marital Satisfaction Inventory Factor Scales

    ERIC Educational Resources Information Center

    Herrington, Rachael L.; Mitchell, Alexandra E.; Castellani, Angela M.; Joseph, Jana I.; Snyder, Douglas K.; Gleaves, David H.

    2008-01-01

    Previous research has identified 2 broad components of distress in intimate relationships: overt conflict, or "disharmony", and emotional distance, or "disaffection". Using confirmatory factor analysis, the authors derived 2 broadband scales of disharmony and disaffection from the Marital Satisfaction Inventory-Revised (D. K. Snyder, 1997),…

  5. An Examination of Relationships between Psychosocial Satisfaction Scales in an Online Student Learning Environment

    ERIC Educational Resources Information Center

    Bookout, James Marshall, Jr.

    2010-01-01

    Research suggests that students who are satisfied with their learning experiences are typically successful and there is a fundamental theory that suggests if the expectations of students are achieved they will be return customers. This study examined the relationships between the psychosocial satisfaction scales in an online student learning…

  6. Another Look at the Relationships Between Similar Scales on the Strong Vocational Interest Blank and Kuder Occupational Interest Survey

    ERIC Educational Resources Information Center

    Carek, Roman

    1972-01-01

    The present study tests the hypothesis that greater relationships will be found between similarly named scales on the two instruments when OIS scale ranks rather than lambda scores are correlated with SVIB standard scores. The hypothesis was not confirmed. (Author)

  7. Inter-relationship between scaling exponents for describing self-similar river networks

    NASA Astrophysics Data System (ADS)

    Yang, Soohyun; Paik, Kyungrock

    2015-04-01

    Natural river networks show well-known self-similar characteristics. Such characteristics are represented by various power-law relationships, e.g., between upstream length and drainage area (exponent h) (Hack, 1957), and in the exceedance probability distribution of upstream area (exponent ɛ) (Rodriguez-Iturbe et al., 1992). It is empirically revealed that these power-law exponents are within narrow ranges. Power-law is also found in the relationship between drainage density (the total stream length divided by the total basin area) and specified source area (the minimum drainage area to form a stream head) (exponent η) (Moussa and Bocquillon, 1996). Considering that above three scaling relationships all refer to fundamental measures of 'length' and 'area' of a given drainage basin, it is natural to hypothesize plausible inter-relationship between these three scaling exponents. Indeed, Rigon et al. (1996) demonstrated the relationship between ɛ and h. In this study, we expand this to a more general ɛ-η-h relationship. We approach ɛ-η relationship in an analytical manner while η-h relationship is demonstrated for six study basins in Korea. Detailed analysis and implications will be presented. References Hack, J. T. (1957). Studies of longitudinal river profiles in Virginia and Maryland. US, Geological Survey Professional Paper, 294. Moussa, R., & Bocquillon, C. (1996). Fractal analyses of tree-like channel networks from digital elevation model data. Journal of Hydrology, 187(1), 157-172. Rigon, R., Rodriguez-Iturbe, I., Maritan, A., Giacometti. A., Tarboton, D. G., & Rinaldo, A. (1996). On Hack's Law. Water Resources Research, 32(11), 3367-3374. Rodríguez-Iturbe, I., Ijjasz-Vasquez, E. J., Bras, R. L., & Tarboton, D. G. (1992). Power law distributions of discharge mass and energy in river basins. Water Resources Research, 28(4), 1089-1093.

  8. Using scale dependent variation in soil properties to describe soil landscape relationships through DSM

    NASA Astrophysics Data System (ADS)

    Corstanje, Ronald; Mayr, Thomas

    2016-04-01

    DSM formalizes the relationship between soil forming factors and the landscape in which they are formed and aims to capture and model the intrinsic spatial variability naturally observed in soils. Covariates, the landscape factors recognized as governing soil formation, vary at different scales and this spatial variation at some scales may be more strongly correlated with soil than at others. Soil forming factors have different domains with distinctive scales, for example geology operates at a coarser scale than land use. By understanding the quantitative relationships between soil and soil forming factors, and their scale dependency, we can start determining the importance of landscape level processes on the formation and observed variation in soils. Three study areas, covered by detailed reconnaissance soil survey, were identified in the Republic of Ireland. Their different pedological and geomorphological characteristics allowed to test scale dependent behaviors across the spectrum of conditions present in the Irish landscape. We considered here three approaches, i) an empirical diagnostic tool in which DSM was applied across a range of scales (20 to 260 m2), ii) the application of wavelets to decompose the DEMs into a series of independent components at varying scales and then used in DSM and finally, iii) a multiscale, window based geostatistical based approach. Applied as a diagnostic approach, we found that wavelets and window based, multiscale geostatistics were effective in identifying the main scales of interaction of the key soil landscape factors (e.g. terrain, geology, land use etc.) and in partitioning the landscape accordingly, we were able to accurately reproduce the observed spatial variation in soils.

  9. Commitment in different relationships statuses: validation study of the personal commitment scale.

    PubMed

    Monteiro, Ana Pego; Costa-Ramalho, Susana; Ribeiro, Maria Teresa; Pinto, Alexandra Marques

    2015-01-01

    This study presents the validation process of the Portuguese version of the short-form Dedication Scale (Rhoades, Stanley, & Markman, 2006; Stanley, 1986), with a sample of 924 participants in different relationship statutes. With 14 items, this short version is recommended by the authors for its simple use, when wanting to measure commitment in romantic relationships. Confirmatory factor analysis showed that the instrument did not have a totally acceptable fit with the data so an exploratory factor analysis was conducted. This revealed a one-dimensional structure of the scale, and led to the exclusion of two items, which relate to a distinct meta-commitment dimension. In sum, the Portuguese version (ECP - Personal Commitment Scale) has 12 items, with good internal consistency (α = .82), correlations item-total between .36 and .60, and good criteria validity (p < .001). Its use for research is therefore appropriate. In a second study, significant differences were found between the participants' four relationship statuses (dating non-cohabiting and cohabiting relationships, formal unions and marriage) (p < .001; η2 p = .03). Results showed that married participants were more committed than those in a formal union, even when controlling for several relational and socio-demographic variables. No differences were found between cohabiting and non-cohabiting dating participants. Men reported higher levels of commitment than women (p < .001; η2 p = .02). Implications and suggestions for future research are discussed. PMID:26037376

  10. Higher photosynthetic capacity and different functional trait scaling relationships in erect bryophytes compared with prostrate species.

    PubMed

    Wang, Zhe; Liu, Xin; Bao, Weikai

    2016-02-01

    Ecophysiological studies of bryophytes have generally been conducted at the shoot or canopy scale. However, their growth forms are diverse, and knowledge of whether bryophytes with different shoot structures have different functional trait levels and scaling relationships is limited. We collected 27 bryophyte species and categorised them into two groups based on their growth forms: erect and prostrate species. Twenty-one morphological, nutrient and photosynthetic traits were quantified. Trait levels and bivariate trait scaling relationships across species were compared between the two groups. The two groups had similar mean values for shoot mass per area (SMA), light saturation point and mass-based nitrogen (N(mass)) and phosphorus concentrations. Erect bryophytes possessed higher values for mass-based chlorophyll concentration (Chl(mass)), light-saturated assimilation rate (A(mass)) and photosynthetic nitrogen/phosphorus use efficiency. N(mass), Chl(mass) and A(mass) were positively related, and these traits were negatively associated with SMA. Furthermore, the slope of the regression of N(mass) versus Chl(mass) was steeper for erect bryophytes than that for prostrate bryophytes, whereas this pattern was reversed for the relationship between Chl(mass) and A(mass). In conclusion, erect bryophytes possess higher photosynthetic capacities than prostrate species. Furthermore, erect bryophytes invest more nitrogen in chloroplast pigments to improve their light-harvesting ability, while the structure of prostrate species permits more efficient light capture. This study confirms the effect of growth form on the functional trait levels and scaling relationships of bryophytes. It also suggests that bryophytes could be good models for investigating the carbon economy and nutrient allocation of plants at the shoot rather than the leaf scale. PMID:26552378

  11. The derivation of scaling relationship between acoustic and electromagnetic scattering by spheres

    SciTech Connect

    Feng, Yongpan; Ge, Junxiang; Wan, Fayu

    2013-11-15

    The rigorous theory of the conversion between the scattering of uniform plane electromagnetic wave by a perfectly conducting sphere and the scattering of uniform plane acoustic wave by a rigid sphere is studied in this paper. The conversion formula between these two different scattering based on two calibration curves is derived, which describes the quantitative relationship between acoustic and electromagnetic wave scattering at arbitrary frequencies by spheres of arbitrary sizes. In addition, the scaling relationship of the sizes of those two spheres and the corresponding frequencies are discussed in detail, and an indirect method of measurement of electromagnetic scattering by the spheres is proposed.

  12. Phylogenetic and morphological relationships between nonvolant small mammals reveal assembly processes at different spatial scales

    PubMed Central

    Luza, André Luís; Gonçalves, Gislene Lopes; Hartz, Sandra Maria

    2015-01-01

    The relative roles of historical processes, environmental filtering, and ecological interactions in the organization of species assemblages vary depending on the spatial scale. We evaluated the phylogenetic and morphological relationships between species and individuals (i.e., inter- and intraspecific variability) of Neotropical nonvolant small mammals coexisting in grassland-forest ecotones, in landscapes and in regions, that is, three different scales. We used a phylogenetic tree to infer evolutionary relationships, and morphological traits as indicators of performance and niche similarities between species and individuals. Subsequently, we applied phylogenetic and morphologic indexes of diversity and distance between species to evaluate small mammal assemblage structures on the three scales. The results indicated a repulsion pattern near forest edges, showing that phylogenetically similar species coexisted less often than expected by chance. The strategies for niche differentiation might explain the phylogenetic repulsion observed at the edge. Phylogenetic and morphological clustering in the grassland and at the forest interior indicated the coexistence of closely related and ecologically similar species and individuals. Coexistence patterns were similar whether species-trait values or individual values were used. At the landscape and regional scales, assemblages showed a predominant pattern of phylogenetic and morphological clustering. Environmental filters influenced the coexistence patterns at three scales, showing the importance of phylogenetically conserved ecological tolerances in enabling taxa co-occurrence. Evidence of phylogenetic repulsion in one region indicated that other processes beyond environmental filtering are important for community assembly at broad scales. Finally, ecological interactions and environmental filtering seemed important at the local scale, while environmental filtering and historical colonization seemed important for community

  13. A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods

    PubMed Central

    2012-01-01

    Background Body size is intimately related to the physiology and ecology of an organism. Therefore, accurate and consistent body mass estimates are essential for inferring numerous aspects of paleobiology in extinct taxa, and investigating large-scale evolutionary and ecological patterns in the history of life. Scaling relationships between skeletal measurements and body mass in birds and mammals are commonly used to predict body mass in extinct members of these crown clades, but the applicability of these models for predicting mass in more distantly related stem taxa, such as non-avian dinosaurs and non-mammalian synapsids, has been criticized on biomechanical grounds. Here we test the major criticisms of scaling methods for estimating body mass using an extensive dataset of mammalian and non-avian reptilian species derived from individual skeletons with live weights. Results Significant differences in the limb scaling of mammals and reptiles are noted in comparisons of limb proportions and limb length to body mass. Remarkably, however, the relationship between proximal (stylopodial) limb bone circumference and body mass is highly conserved in extant terrestrial mammals and reptiles, in spite of their disparate limb postures, gaits, and phylogenetic histories. As a result, we are able to conclusively reject the main criticisms of scaling methods that question the applicability of a universal scaling equation for estimating body mass in distantly related taxa. Conclusions The conserved nature of the relationship between stylopodial circumference and body mass suggests that the minimum diaphyseal circumference of the major weight-bearing bones is only weakly influenced by the varied forces exerted on the limbs (that is, compression or torsion) and most strongly related to the mass of the animal. Our results, therefore, provide a much-needed, robust, phylogenetically corrected framework for accurate and consistent estimation of body mass in extinct terrestrial

  14. Prediction of glucuronidated drug clearance in pediatrics (≤5 years): An allometric approach.

    PubMed

    Mahmood, Iftekhar

    2015-03-01

    Children are not small adults. The differences between children of different age groups and adults are not merely due to body weight, but also due to physiological and biochemical differences resulting in different rates of drug metabolism or renal clearance. Glucuronidation is an important pathway of drug metabolism. Therefore, the objective of this study is to evaluate the predictive performance of several allometric exponents in children of ≤5 years for the total clearance of drugs which are mainly metabolized by glucuronidation. Four exponents (0.75, 1.0, 1.2, or 1.4) on the body weights and an allometric model developed from adults were evaluated. The four exponents and the allometric model were examined to determine the suitability of the method(s) to predict the clearances of drugs which are glucuronidated in children ≤5 years of age. Based on the analysis of ten drugs, it was noted that the combination of two allometric exponents 1.2 (for children ≤3 months) and 1.0 (for children ≥3 months ≤5 years) can be used to predict mean clearances of drugs which are mainly metabolized by glucuronidation. The suggested approach may be used to estimate a first-in-pediatric dose to initiate a pediatric clinical trial. PMID:24519316

  15. Relationship between the brightness in the coronal green line and magnetic fields on various scales

    NASA Astrophysics Data System (ADS)

    Badalyan, O. G.

    2013-03-01

    The relationship between the brightness in the FeXIV 530.3 nm coronal green line and magnetic fields on various scales in the corona is studied quantitatively. The cross-correlations of the corresponding synoptic maps for 1977-2001 have been calculated. Maps of the brightness of the coronal green line are constructed using daily monitoring data. Maps of the magnetic field are constructed separately for fields on large and small spatial scales, based on computations in a potential approximation using photospheric observations for distances of 1.1 R ⊙ carried out at the Wilcox Solar Observatory. The correlations between the brightness in the coronal green line and the magnetic-field strengths on various scales as a function of latitude have a cyclic character. The correlation coefficients in the spot-formation zone are positive. Here, the green-line brightness corresponds mainly to the strength of small-scale fields, corresponding to the sizes of large active regions and activity complexes. The correlation coefficients are sign-variable above 40° latitude, and reach their greatest positive and negative values at the cyclemaximum and minimum. Larger-scale fields influence the green-line brightness at higher latitudes and near the phase of the cycle minimum. The results obtained can be used to investigate mechanisms for heating the corona. The relationship between the results obtained and the subsurface and deep solar dynamos are also discussed.

  16. Spatial Relationships between Polychaete Assemblages and Environmental Variables over Broad Geographical Scales

    PubMed Central

    Benedetti-Cecchi, Lisandro; Iken, Katrin; Konar, Brenda; Cruz-Motta, Juan; Knowlton, Ann; Pohle, Gerhard; Castelli, Alberto; Tamburello, Laura; Mead, Angela; Trott, Tom; Miloslavich, Patricia; Wong, Melisa; Shirayama, Yoshihisa; Lardicci, Claudio; Palomo, Gabriela; Maggi, Elena

    2010-01-01

    This study examined spatial relationships between rocky shore polychaete assemblages and environmental variables over broad geographical scales, using a database compiled within the Census of Marine Life NaGISA (Natural Geography In Shore Areas) research program. The database consisted of abundance measures of polychaetes classified at the genus and family levels for 74 and 93 sites, respectively, from nine geographic regions. We tested the general hypothesis that the set of environmental variables emerging as potentially important drivers of variation in polychaete assemblages depend on the spatial scale considered. Through Moran's eigenvector maps we indentified three submodels reflecting spatial relationships among sampling sites at intercontinental (>10000 km), continental (1000–5000 km) and regional (20–500 km) scales. Using redundancy analysis we found that most environmental variables contributed to explain a large and significant proportion of variation of the intercontinental submodel both for genera and families (54% and 53%, respectively). A subset of these variables, organic pollution, inorganic pollution, primary productivity and nutrient contamination was also significantly related to spatial variation at the continental scale, explaining 25% and 32% of the variance at the genus and family levels, respectively. These variables should therefore be preferably considered when forecasting large-scale spatial patterns of polychaete assemblages in relation to ongoing or predicted changes in environmental conditions. None of the variables considered in this study were significantly related to the regional submodel. PMID:20886075

  17. Development and psychometric analysis of the student–teacher relationship scale – short form

    PubMed Central

    Settanni, Michele; Longobardi, Claudio; Sclavo, Erica; Fraire, Michela; Prino, Laura E.

    2015-01-01

    The purpose of this study is the construction and validation of an Italian Short Form version of the Student–Teacher Relationship Scale (STRS; Fraire et al., 2013). The analyses were conducted on 1256 students and 210 teachers. The STRS is a self-report measure assessing teachers’ perception of the quality of their relationship with students ranging from preschool to third grade. The items were selected from the original Italian adaptation of the regular STRS (Pianta, 2001) through Rasch (1960/1980) analysis, which allowed us to identify a subset of items with proven psychometric properties. The STRS-SF consists of two subscales: Conflict (eight items) and Closeness (six items). Results indicate that the 14-item instrument shows good internal consistency (α>0.80), high correlations with the scales from the regular STRS (r > 0.90) and equivalence across gender. PMID:26167156

  18. Distance to the scaling law: a useful approach for unveiling relationships between crime and urban metrics.

    PubMed

    Alves, Luiz G A; Ribeiro, Haroldo V; Lenzi, Ervin K; Mendes, Renio S

    2013-01-01

    We report on a quantitative analysis of relationships between the number of homicides, population size and ten other urban metrics. By using data from Brazilian cities, we show that well-defined average scaling laws with the population size emerge when investigating the relations between population and number of homicides as well as population and urban metrics. We also show that the fluctuations around the scaling laws are log-normally distributed, which enabled us to model these scaling laws by a stochastic-like equation driven by a multiplicative and log-normally distributed noise. Because of the scaling laws, we argue that it is better to employ logarithms in order to describe the number of homicides in function of the urban metrics via regression analysis. In addition to the regression analysis, we propose an approach to correlate crime and urban metrics via the evaluation of the distance between the actual value of the number of homicides (as well as the value of the urban metrics) and the value that is expected by the scaling law with the population size. This approach has proved to be robust and useful for unveiling relationships/behaviors that were not properly carried out by the regression analysis, such as [Formula: see text] the non-explanatory potential of the elderly population when the number of homicides is much above or much below the scaling law, [Formula: see text] the fact that unemployment has explanatory potential only when the number of homicides is considerably larger than the expected by the power law, and [Formula: see text] a gender difference in number of homicides, where cities with female population below the scaling law are characterized by a number of homicides above the power law. PMID:23940525

  19. Relationships between avian richness and landscape structure at multiple scales using multiple landscapes

    USGS Publications Warehouse

    Mitchell, M.S.; Rutzmoser, S.H.; Wigley, T.B.; Loehle, C.; Gerwin, J.A.; Keyser, P.D.; Lancia, R.A.; Perry, R.W.; Reynolds, C.J.; Thill, R.E.; Weih, R.; White, D.; Wood, P.B.

    2006-01-01

    Little is known about factors that structure biodiversity on landscape scales, yet current land management protocols, such as forest certification programs, place an increasing emphasis on managing for sustainable biodiversity at landscape scales. We used a replicated landscape study to evaluate relationships between forest structure and avian diversity at both stand and landscape-levels. We used data on bird communities collected under comparable sampling protocols on four managed forests located across the Southeastern US to develop logistic regression models describing relationships between habitat factors and the distribution of overall richness and richness of selected guilds. Landscape models generated for eight of nine guilds showed a strong relationship between richness and both availability and configuration of landscape features. Diversity of topographic features and heterogeneity of forest structure were primary determinants of avian species richness. Forest heterogeneity, in both age and forest type, were strongly and positively associated with overall avian richness and richness for most guilds. Road density was associated positively but weakly with avian richness. Landscape variables dominated all models generated, but no consistent patterns in metrics or scale were evident. Model fit was strong for neotropical migrants and relatively weak for short-distance migrants and resident species. Our models provide a tool that will allow managers to evaluate and demonstrate quantitatively how management practices affect avian diversity on landscapes.

  20. Scale indicators of social exchange relationships: a comparison of relative content validity.

    PubMed

    Colquitt, Jason A; Baer, Michael D; Long, David M; Halvorsen-Ganepola, Marie D K

    2014-07-01

    Although social exchange theory has become one of the most oft-evoked theories in industrial and organizational psychology, there remains no consensus about how to measure its key mechanism: social exchange relationships (Blau, 1964). Drawing on Cropanzano and Byrne's (2000) review of contemporary social exchange theorizing, we examined the content validity of perceived support, exchange quality, affective commitment, trust, and psychological contract fulfillment as indicators of social exchange relationships. We used Hinkin and Tracey's (1999) quantitative approach to content validation, which asks participants to rate the correspondence between scale items and definitions of intended (and unintended) constructs. Our results revealed that some of the most frequently utilized indicators of social exchange relationships--perceived support and exchange quality--were significantly less content valid than rarely used options like affect-based trust. Our results also revealed that 2 direct measures--Bernerth, Armenakis, Feild, Giles, and Walker's (2007) scale and a scale created for this study--were content valid. We discuss the implications of these results for future applications of social exchange theory. PMID:24708267

  1. Measuring Teacher-Child Relationships in the Greek Kindergarten Setting: A Validity Study of the Student-Teacher Relationship Scale-Short Form

    ERIC Educational Resources Information Center

    Tsigilis, Nikolaos; Gregoriadis, Athanasios

    2008-01-01

    Research Findings: The present study was designed to examine the factorial validity of the Student-Teacher Relationship Scale-Short Form (STRS-SF; R. C. Pianta, 2001) and its invariance across gender in the Greek educational context. The STRS-SF comprises 15 items that measure 2 dimensions of teacher-child relationships: Closeness and Conflict.…

  2. Adding constraints to predation through allometric relation of scats to consumption.

    PubMed

    Chakrabarti, Stotra; Jhala, Yadvendradev V; Dutta, Sutirtha; Qureshi, Qamar; Kadivar, Riaz F; Rana, Vishwadipsinh J

    2016-05-01

    A thorough understanding of mechanisms of prey consumption by carnivores and the constraints on predation help us in evaluating the role of carnivores in an ecosystem. This is crucial in developing appropriate management strategies for their conservation and mitigating human-carnivore conflict. Current models on optimal foraging suggest that mammalian carnivores would profit most from killing the largest prey that they can subdue with minimal risk of injury to themselves. Wild carnivore diets are primarily estimated through analysis of their scats. Using extensive feeding experiments (n = 68) on a wide size range (4·5-130 kg) of obligate carnivores - lion, leopard, jungle cat and domestic cat, we parameterize biomass models that best relate consumption to scat production. We evaluate additional constraints of gut fill, prey digestibility and carcass utilization on carnivory that were hereto not considered in optimal foraging studies. Our results show that patterns of consumption to scat production against prey size are similar and asymptotic, contrary to established linear models, across these carnivores after accounting for the effect of carnivore size. This asymptotic, allometric relationship allowed us to develop a generalized model: biomass consumed per collectable scat/predator weight = 0·033-0·025exp(-4·284(prey weight/predator weight)) , which is applicable to all obligate carnivores to compute prey biomass consumed from scats. Our results also depict a relationship for prey digestibility which saturates at about 90% for prey larger than predator size. Carcass utilization declines exponentially with prey size. These mechanisms result in digestible biomass saturating at prey weights approximately equal to predator weight. Published literature on consumption by tropical carnivores that has relied on linear biomass models is substantially biased. We demonstrate the nature of these biases by correcting diets of tiger, lion and leopard in recent

  3. Evolutionary relationships of flavobacterial and enterobacterial endosymbionts with their scale insect hosts (Hemiptera: Coccoidea).

    PubMed

    Rosenblueth, Mónica; Sayavedra, L; Sámano-Sánchez, H; Roth, A; Martínez-Romero, E

    2012-11-01

    Flavobacteria and Enterobacteriaceae have been previously reported as scale insect endosymbionts. The purpose of this work was twofold: first, to screen different scale insect families for the presence of these endosymbionts by PCR analyses and second, to elucidate the history of cophylogeny between these bacteria and the insects by analysing a portion of 16S rRNA and 18S rRNA gene sequences by two reconciliation tools, CoRe-PA and Jane. From a survey of 27 scale insects within seven families, we identified Flavobacteria and Enterobacteriaceae as coexisting in ten species that belong to the Ortheziidae, Monophlebidae, Diaspididae and Coccidae families, and we frequently found two closely related enterobacteria harboured in the same individual. Analyses performed with CoRe-PA and Jane suggest that Flavobacteria from the scale insects analysed have a unique origin, except for Candidatus Brownia rhizoecola (Flavobacteria of Pseudococcidae, Phenacoccinae), which seems to come from a nonscale insect. Nevertheless, cospeciation between Flavobacteria and scale insects is suggested only within the families Monophlebidae, Ortheziidae and Diaspididae, and host switches seem to have occurred from the ancestors of Monophlebidae and Ortheziidae to insects from families Coccidae, Lecanodiaspididae, Eriococcidae and Pseudococcidae. Our analyses suggest that Enterobacteriaceae underwent more evolutionary events (losses, duplications and host switches), and their phylogenies showed a lower proportion of congruent nodes between host and bacteria, indicating a more relaxed relationship with scale insects compared with Flavobacteria. PMID:22994649

  4. Scaling relationships of joint and vein arrays from The Burren, Co. Clare, Ireland

    NASA Astrophysics Data System (ADS)

    Gillespie, P. A.; Walsh, J. J.; Watterson, J.; Bonson, C. G.; Manzocchi, T.

    2001-02-01

    We present a study of the systematics of veins and joints in Carboniferous limestones of The Burren, Ireland. Scaling relationships were established for fracture arrays mapped from low elevation aerial photographs that image fractures on numerous limestone pavements for areas up to ca 1 km 2. The veins and joints occur in the same sequence, but have contrasting scaling properties. The veins strike north-south and cut many beds to form vertically persistent, non-stratabound arrays. They are strongly clustered and have scale invariant geometric properties. Vein geometries suggest they grew sub-critically under relatively high differential stresses, during north-south directed Variscan compression. The joints form stratabound arrays, with regular spacings that scale with bed thickness. They show greater strike variation than the veins and have lognormal length distributions. The joints formed during uplift, under low-differential stress conditions. The contrasting scaling properties of the joints and veins are attributed to different overburden stresses at the time of formation. The veins formed at greater depths than the joints, in conditions that favoured fracture propagation across mechanical discontinuities, resulting in the development of non-stratabound scaling properties.

  5. Online Friendship, Romance, and Sex: Properties and Associations of the Online Relationship Initiation Scale.

    PubMed

    Harris, Keith M; Aboujaoude, Elias

    2016-08-01

    Online relationships are increasingly central to many people's lives. As a result, there is a growing need to scientifically examine their psychosocial implications. This study developed and tested the Online Relationship Initiation Scale (ORIS) through classical and item response theory analyses to address this need. An anonymous online survey included 713 adults, aged 18-71 years. The ORIS was tested on psychometric properties and examined for associations with gender and several standardized psychosocial measures. Results demonstrated unidimensionality of nine items, strong factor loadings, and high internal consistency (α = 0.90, ωt = 0.94). All items captured significant information on the latent trait and none showed differential item functioning by sex, age group, or ethnicity. General linear modeling confirmed hypotheses that men were more likely than women to initiate online relationships. Online relationship initiation was not strongly associated with perceived social support, but was positively related to financial distress, and willingness to engage in infidelity or unprotected sex. The ORIS was negatively associated with age and satisfaction with life and showed modest interactions with ethnicity and hours online. This study provided empirical evidence for an interpersonal relationship initiation construct. The ORIS was shown to be a psychometrically sound instrument for evaluating online interpersonal behaviors and their associations with psychosocial and demographic factors. Such psychometrically sound instruments can be useful in exploring online interpersonal behaviors and their significance. PMID:27447244

  6. Intraspecific Scaling Relationships Between Crawling Speed and Body Size in a Gastropod.

    PubMed

    Hemmert, Heather M; Baltzley, Michael J

    2016-02-01

    Across various modes of locomotion, body size and speed are often correlated both between and within species. Among the gastropods, however, current data are minimal for interspecific and intraspecific scaling relationships. In this study, we tested the relationships between various measurements of body size and crawling speed in the terrestrial snail Cornu aspersum. We also investigated the relationships between crawling speed, muscular wave frequency, and muscular wavelength, because--while these relationships within individuals are well studied--the relationships among individuals are unknown. We recorded snails crawling on both a horizontal and a vertical surface. We found that when they crawled on a horizontal surface, foot length was positively correlated with pedal wavelength and crawling speed, but was not correlated with wave frequency. In comparison, when they crawled on a vertical surface, foot length was positively correlated with wavelength, negatively correlated with wave frequency, and not correlated with crawling speed. Body mass had no correlation with crawling speed when snails were crawling on a horizontal surface, but was negatively correlated with speed when snails crawled on a vertical surface. PMID:26896180

  7. Geometrical constraints in the scaling relationships between genome size, cell size and cell cycle length in herbaceous plants

    PubMed Central

    Šímová, Irena; Herben, Tomáš

    2012-01-01

    Plant nuclear genome size (GS) varies over three orders of magnitude and is correlated with cell size and growth rate. We explore whether these relationships can be owing to geometrical scaling constraints. These would produce an isometric GS–cell volume relationship, with the GS–cell diameter relationship with the exponent of 1/3. In the GS–cell division relationship, duration of processes limited by membrane transport would scale at the 1/3 exponent, whereas those limited by metabolism would show no relationship. We tested these predictions by estimating scaling exponents from 11 published datasets on differentiated and meristematic cells in diploid herbaceous plants. We found scaling of GS–cell size to almost perfectly match the prediction. The scaling exponent of the relationship between GS and cell cycle duration did not match the prediction. However, this relationship consists of two components: (i) S phase duration, which depends on GS, and has the predicted 1/3 exponent, and (ii) a GS-independent threshold reflecting the duration of the G1 and G2 phases. The matches we found for the relationships between GS and both cell size and S phase duration are signatures of geometrical scaling. We propose that a similar approach can be used to examine GS effects at tissue and whole plant levels. PMID:21881135

  8. The scaling relationship between telescope cost and aperture size for very large telescopes

    NASA Technical Reports Server (NTRS)

    van Belle, Gerard T.; Meinel, Aden Baker; Meinel, Marjorie Pettit

    2004-01-01

    Cost data for ground-based telescopes of the last century are analyzed for trends in the relationship between aperture size and cost. We find that for apertures built prior to 1980, costs scaled as aperture size to the 2.8 power, which is consistent with the precious finding of Meinel (1978). After 1980, 'traditional' monolithic mirror telescope costs have scaled as aperture to the 2.5 power. The large multiple mirror telescopes built or in construction during this time period (Keck, LBT, GTC) appear to deviate from this relationship with significant cost savings as a result, although it is unclear what power law such structures follow. We discuss the implications of the current cost-aperture size data on the proposed large telescope projects of the next ten to twenty years. Structures that naturally tend towards the 2.0 power in the cost-aperture relationship will be the favorable choice for future extremely large apertures; out expectation is that space-based structures will ultimately gain economic advantage over ground-based ones.

  9. Biogeographic affinity helps explain productivity-richness relationships at regional and local scales

    USGS Publications Warehouse

    Harrison, S.; Grace, J.B.

    2007-01-01

    The unresolved question of what causes the observed positive relationship between large-scale productivity and species richness has long interested ecologists and evolutionists. Here we examine a potential explanation that we call the biogeographic affinity hypothesis, which proposes that the productivity-richness relationship is a function of species' climatic tolerances that in turn are shaped by the earth's climatic history combined with evolutionary niche conservatism. Using botanical data from regions and sites across California, we find support for a key prediction of this hypothesis, namely, that the productivity-species richness relationship differs strongly and predictably among groups of higher taxa on the basis of their biogeographic affinities (i.e., between families or genera primarily associated with north-temperate, semiarid, or desert zones). We also show that a consideration of biogeographic affinity can yield new insights on how productivity-richness patterns at large geographic scales filter down to affect patterns of species richness and composition within local communities. ?? 2007 by The University of Chicago. All rights reserved.

  10. Quantitative relationships between watershed-scale stressors and estuarine condition for mid-Atlantic region

    SciTech Connect

    Paul, J.F.; Hale, S.S.; Comeleo, R.L.; Copeland, J.; August, P.V.

    1995-12-31

    A pilot project has been conducted that developed quantitative relationships between watershed-scale (landscape) stressors and sediment contamination for sub-estuaries within Chesapeake Bay. The landscape stressors, land use patterns (derived from classified, contemporary satellite imagery) and point source pollution, were spatially analyzed for each individual watershed of 25 sub-estuaries using a geographic information system. Sediment contamination data for the sub-estuaries, available from the Environmental Monitoring and Assessment Program (EMAP), were statistically reduced to one principal component for the metals and organics. Non-parametric statistical techniques were used to develop empirical relationships between sediment contamination and developed land (positive), herbaceous land (negative) and point source loadings (positive). These analyses have been extended to (1) include approximately 80 subestuaries across the mid-Atlantic region for which EMAP data were available, and (2) relate landscape stressors with estuarine condition. The measure of estuarine condition was an index of benthic quality developed by EMAP. The only available land use data set for the entire mid-Atlantic region was from US Geological Survey Land Use Data Analysis database, which is of 1970s vintage. Because of the dramatic differences in spatial area of the sub-estuaries in the mid-Atlantic region, adjustments for differing hydrologic regimes had to be factored into the analysis. Results indicate that it is possible to develop relationships between watershed-scale stressors and estuarine condition across large geographic regions.

  11. Biogeographic affinity helps explain productivity-richness relationships at regional and local scales.

    PubMed

    Harrison, Susan; Grace, James B

    2007-08-01

    The unresolved question of what causes the observed positive relationship between large-scale productivity and species richness has long interested ecologists and evolutionists. Here we examine a potential explanation that we call the biogeographic affinity hypothesis, which proposes that the productivity-richness relationship is a function of species' climatic tolerances that in turn are shaped by the earth's climatic history combined with evolutionary niche conservatism. Using botanical data from regions and sites across California, we find support for a key prediction of this hypothesis, namely, that the productivity-species richness relationship differs strongly and predictably among groups of higher taxa on the basis of their biogeographic affinities (i.e., between families or genera primarily associated with north-temperate, semiarid, or desert zones). We also show that a consideration of biogeographic affinity can yield new insights on how productivity-richness patterns at large geographic scales filter down to affect patterns of species richness and composition within local communities. PMID:17874384

  12. Scaling of swim speed in breath-hold divers.

    PubMed

    Watanabe, Yuuki Y; Sato, Katsufumi; Watanuki, Yutaka; Takahashi, Akinori; Mitani, Yoko; Amano, Masao; Aoki, Kagari; Narazaki, Tomoko; Iwata, Takashi; Minamikawa, Shingo; Miyazaki, Nobuyuki

    2011-01-01

    1. Breath-hold divers are widely assumed to descend and ascend at the speed that minimizes energy expenditure per distance travelled (the cost of transport (COT)) to maximize foraging duration at depth. However, measuring COT with captive animals is difficult, and empirical support for this hypothesis is sparse. 2. We examined the scaling relationship of swim speed in free-ranging diving birds, mammals and turtles (37 species; mass range, 0·5-90,000 kg) with phylogenetically informed statistical methods and derived the theoretical prediction for the allometric exponent under the COT hypothesis by constructing a biomechanical model. 3. Swim speed significantly increased with mass, despite considerable variations around the scaling line. The allometric exponent (0·09) was statistically consistent with the theoretical prediction (0·05) of the COT hypothesis. 4. Our finding suggests a previously unrecognized advantage of size in divers: larger animals swim faster and thus could travel longer distance, search larger volume of water for prey and exploit a greater range of depths during a given dive duration. 5. Furthermore, as predicted from the model, endotherms (birds and mammals) swam faster than ectotherms (turtles) for their size, suggesting that metabolic power production limits swim speed. Among endotherms, birds swam faster than mammals, which cannot be explained by the model. Reynolds numbers of small birds (<2 kg) were close to the lower limit of turbulent flow (∼ 3 × 10(5) ), and they swam fast possibly to avoid the increased drag associated with flow transition. PMID:20946384

  13. Downstream hydraulic geometry relationships: Gathering reference reach-scale width values from LiDAR

    NASA Astrophysics Data System (ADS)

    Sofia, G.; Tarolli, P.; Cazorzi, F.; Dalla Fontana, G.

    2015-12-01

    This paper examines the ability of LiDAR topography to provide reach-scale width values for the analysis of downstream hydraulic geometry relationships along some streams in the Dolomites (northern Italy). Multiple reach-scale dimensions can provide representative geometries and statistics characterising the longitudinal variability in the channel, improving the understanding of geomorphic processes across networks. Starting from the minimum curvature derived from a LiDAR DTM, the proposed algorithm uses a statistical approach for the identification of the scale of analysis, and for the automatic characterisation of reach-scale bankfull widths. The downstream adjustment in channel morphology is then related to flow parameters (drainage area and stream power). With the correct planning of a LiDAR survey, uncertainties in the procedure are principally due to the resolution of the DTM. The outputs are in general comparable in quality to field survey measurements, and the procedure allows the quick comparison among different watersheds. The proposed automatic approach could improve knowledge about river systems with highly variable widths, and about systems in areas covered by vegetation or inaccessible to field surveys. With proven effectiveness, this research could offer an interesting starting point for the analysis of differences between watersheds, and to improve knowledge about downstream channel adjustment in relation, for example, to scale and landscape forcing (e.g. sediment transport, tectonics, lithology, climate, geomorphology, and anthropic pressure).

  14. Geometrical analysis of deformation band lozenges and their scaling relationships to fault lenses

    NASA Astrophysics Data System (ADS)

    Awdal, Abdullah; Healy, David; Alsop, G. Ian

    2014-09-01

    Deformation bands can influence fluid flow in sandstone hydrocarbon reservoirs and therefore, understanding the geometrical attributes of individual bands and their patterns is a critical step in quantifying their connectivity. We present a geometrical study of deformation band lozenges, which are rock volumes contained between deformation bands, and fault lenses, which are rock volumes bounded by slip surfaces in fault cores. We investigate the statistical trends among data sets for deformation band lozenges and fault lenses in sandstones from the Moray Firth (Scotland) and southeastern Utah (USA), and explore their potential correlation to other attributes of the fracture pattern and petrophysical properties. The aspect ratio of lozenges, that represents the ratio of length or height to the maximum thickness of a lozenge, displays an oblate-shaped geometry in relation to fault-zone orientation. The length-thickness scaling relationships of lozenges are statistically similar to lenses. The scaling relationships show a slope break between lozenges bounded by deformation bands and lenses bounded by slip surfaces in the fault core. This break is inferred to mark the boundary between the lozenge domain and lens domain, and is likely due to a deformation transition from distributed strain for deformation bands to localised strain for slip surfaces. Furthermore, the integration of geometrical analysis with an understanding of scaling properties can help to make better predictions of fractures and fault properties in subsurface reservoirs.

  15. Relationships between Human Population Density and Burned Area at Continental and Global Scales

    PubMed Central

    Bistinas, Ioannis; Oom, Duarte; Sá, Ana C. L.; Harrison, Sandy P.; Prentice, I. Colin; Pereira, José M. C.

    2013-01-01

    We explore the large spatial variation in the relationship between population density and burned area, using continental-scale Geographically Weighted Regression (GWR) based on 13 years of satellite-derived burned area maps from the global fire emissions database (GFED) and the human population density from the gridded population of the world (GPW 2005). Significant relationships are observed over 51.5% of the global land area, and the area affected varies from continent to continent: population density has a significant impact on fire over most of Asia and Africa but is important in explaining fire over < 22% of Europe and Australia. Increasing population density is associated with both increased and decreased in fire. The nature of the relationship depends on land-use: increasing population density is associated with increased burned are in rangelands but with decreased burned area in croplands. Overall, the relationship between population density and burned area is non-monotonic: burned area initially increases with population density and then decreases when population density exceeds a threshold. These thresholds vary regionally. Our study contributes to improved understanding of how human activities relate to burned area, and should contribute to a better estimate of atmospheric emissions from biomass burning. PMID:24358108

  16. Training pilots to visualize large-scale spatial relationships in a stereoscopic display

    NASA Astrophysics Data System (ADS)

    Mowafy, Lyn; Thurman, Richard A.

    1993-09-01

    In flying air intercepts, a fighter pilot must plan most tactical maneuvers well before acquiring visual contact. Success depends on one's ability to create an accurate mental model of dynamic 3D spatial relationships from 2D information displays. This paper describes an Air Force training program for visualizing large- scale dynamic spatial relationships. It employs a low-cost, portable system in which the helmet-mounted stereoscopic display reveals the unobservable spatial relationships in a virtual world. We also describe recent research which evaluated the training effectiveness of this interactive three-dimensional display technology. Three display formats have been tested for their impact on the pilot's ability to encode, retain and recall functionally relevant spatial information: (1) a set of 2D orthographic plan views, (2) a flat panel 3D perspective rendering and, (3) the 3D virtual environment. Trainees flew specified air intercepts and reviewed the flights in one of the display formats. Experts' trajectories were provided for comparison. After training, flight performance was tested on a new set of scenarios. Differences in pilots' performances under the three formats suggest how virtual environment displays can aid people learning to visualize 3D spatial relationships from 2D information.

  17. Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes

    NASA Astrophysics Data System (ADS)

    Passarelli, L.; Rivalta, E.; Shuler, A.

    2014-01-01

    As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusion was followed by a series of smaller intrusions. By performing a statistical analysis of these rifting episodes, we demonstrate that dike intrusions obey scaling relationships similar to earthquakes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, and the long-term release of geodetic moment is governed by a relationship consistent with the Omori law. Due to the effects of magma supply, the timing of secondary dike intrusions differs from that of the aftershocks. This work provides evidence of self-similarity in the rifting process.

  18. Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes

    PubMed Central

    L., Passarelli; E., Rivalta; A., Shuler

    2014-01-01

    As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusion was followed by a series of smaller intrusions. By performing a statistical analysis of these rifting episodes, we demonstrate that dike intrusions obey scaling relationships similar to earthquakes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, and the long-term release of geodetic moment is governed by a relationship consistent with the Omori law. Due to the effects of magma supply, the timing of secondary dike intrusions differs from that of the aftershocks. This work provides evidence of self-similarity in the rifting process. PMID:24469260

  19. The Femininity Ideology Scale (FIS): dimensions and its relationship to anxiety and feminine gender role stress.

    PubMed

    Richmond, Katherine; Levant, Ronald; Smalley, Bryant; Cook, Stephen

    2015-01-01

    The purpose of this study was to conduct a confirmatory factor analytic investigation of the Femininity Ideology Scale (FIS) and to assess whether feminine gender role stress mediated the relationship between femininity ideology and anxiety. During the 2010-2011 academic year, a convenience sample of 606 college women were recruited from three universities and one college. Confirmatory factor analysis supported a four- versus the hypothesized five-factor model, resulting in the elimination of the Dependency/Deference factor. Mediation analysis using structural equation modeling indicated no direct relationship between Femininity Ideology and Anxiety, although an indirect one was observed, mediated through Feminine Gender Role Stress. The results are discussed in terms of possible changes in contemporary notions of femininity, and the utility of using the FIS in applied therapeutic settings. PMID:25719527

  20. Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes.

    PubMed

    Passarelli, L; Rivalta, E; Shuler, A

    2014-01-01

    As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusion was followed by a series of smaller intrusions. By performing a statistical analysis of these rifting episodes, we demonstrate that dike intrusions obey scaling relationships similar to earthquakes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, and the long-term release of geodetic moment is governed by a relationship consistent with the Omori law. Due to the effects of magma supply, the timing of secondary dike intrusions differs from that of the aftershocks. This work provides evidence of self-similarity in the rifting process. PMID:24469260

  1. Allometric constraints on Sr/Ca and Ba/Ca partitioning in terrestrial mammalian trophic chains.

    PubMed

    Balter, Vincent

    2004-03-01

    In biological systems, strontium (Sr) and barium (Ba) are two non-essential elements, in comparison to calcium (Ca) which is essential. The Sr/Ca and Ba/Ca ratios tend to decrease in biochemical pathways which include Ca as an essential element, and these processes are termed biopurification of Ca. The quantitative pathway of the biopurification of Ca in relation to Sr and Ba between two biological reservoirs ( Rn and R(n -1)) is measured with an observed ratio (OR) expressed by the (Sr/Ca) Rn /(Sr/Ca)( Rn-1) and (Ba/Ca) Rn /(Ba/Ca)( Rn-1) ratios. For a mammalian organism, during the whole biopurification of Ca starting with the diet to the ultimate reservoir of Ca which is the bone, the mean values for ORSr and ORBa are 0.25 and 0.2, respectively. In this study, published Sr/Ca and Ba/Ca ratios are used for three sets of soils, plants, and bones of herbivorous and carnivorous mammals, each comprising a trophic chain, to illustrate the biopurification of Ca at the level of trophic chains. Calculated ORSr and ORBa of herbivore bones in relation to plants and of bones of carnivores in relation to bones of herbivores give ORSr=0.30+/-0.08 and ORBa=0.16+/-0.08, thus suggesting that trophic chains reflect the Sr/Ca and Ba/Ca fluxes that are prevalent at the level of a mammalian organism. The slopes of the three regression equations of log(Sr/Ca) vs. log(Ba/Ca) are similar, indicating that the process of biopurification of Ca with respect to Sr and Ba is due to biological processes and is independent of the geological settings. Modifications of the logarithmic expression of the Sr/Ca and Ba/Ca relationship allow a new formula of the biopurification process to be deduced, leading to the general equation ORBa=ORSr(1.79+/-0.33), where the allometric coefficient is the mean of the slopes of the three regression equations. Some recent examples are used to illustrate this new analysis of predator-prey relations between mammals. This opens up new possibilities for the

  2. From Correlation to Causality: Statistical Approaches to Learning Regulatory Relationships in Large-Scale Biomolecular Investigations.

    PubMed

    Ness, Robert O; Sachs, Karen; Vitek, Olga

    2016-03-01

    Causal inference, the task of uncovering regulatory relationships between components of biomolecular pathways and networks, is a primary goal of many high-throughput investigations. Statistical associations between observed protein concentrations can suggest an enticing number of hypotheses regarding the underlying causal interactions, but when do such associations reflect the underlying causal biomolecular mechanisms? The goal of this perspective is to provide suggestions for causal inference in large-scale experiments, which utilize high-throughput technologies such as mass-spectrometry-based proteomics. We describe in nontechnical terms the pitfalls of inference in large data sets and suggest methods to overcome these pitfalls and reliably find regulatory associations. PMID:26731284

  3. Assessing Client-Caregiver Relationships and the Applicability of the "Student-Teacher Relationship Scale" for People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Roeden, John M.; Maaskant, Marian A.; Koomen, Helma M. Y.; Candel, Math J. J. M.; Curfs, Leopold M. G.

    2012-01-01

    Improvements in client-caregiver relationships may lead to improvements in the quality of life of clients with intellectual disabilities (ID). For this reason, interventions aimed at influencing these relationships are important. To gain insight into the nature and intention of these relationships in the ID population, suitable measurement…

  4. Relationship between bird abundances and landscape characteristics: the influence of scale.

    PubMed

    Brennan, Sarah P; Schnell, Gary D

    2005-06-01

    Scale is important to consider when investigating effects of the environment on a species. Breeding Bird Survey (BBS) data and landscape metrics derived from aerial photographs were evaluated to determine how relationships of bird abundances with landscape variables changed over a continuous range of 16 spatial scales. We analyzed the average number of birds per stop (1985-1994) for five songbird species (family Cardinalidae) for each of 50 stops on 198 BBS transects throughout six states in the Central Plains, USA. Land along each transect was categorized into six cover types, and landscape metrics of fractal dimension (a measure of shape complexity of habitat patches), edge density, patch density, and percent area were calculated, with principal components used to construct composite environmental variables. Associations of bird abundances and landscape variables changed in accordance with small scale changes. Abundances of three species were correlated with edge density and one with component I, which subsumes initial variables of patch density for urban, closed forest, open forest, and open country. Fractal dimension and component II (summarizing amount of closed forest versus open country) were associated with the most species. Correlation patterns of fractal dimension with northern cardinal (Cardinalis cardinalis) and painted bunting (Passerina ciris) abundances were similar, with highest correlations at intermediate to small scales, suggesting indirectly that these species thrive in areas where local habitat conditions are most important. Multiscale analysis can provide insight into the spatial scale(s) at which species respond, a topic of intrinsic scientific interest with applied implications for researchers establishing protocols to assess and monitor avian populations. PMID:15952521

  5. Allometric Prediction of Energy Expenditure in Infants and Children

    PubMed Central

    Blinman, Thane; Cook, Robin

    2011-01-01

    Predicting energy needs in children is complicated by the wide range of patient sizes, confusing traditional estimation equations, nonobjective stress-activity factors, and so on. These complications promote errors in bedside estimates of nutritional needs by rendering the estimation methods functionally unavailable to bedside clinicians. Here, the authors develop a simple heuristic energy prediction equation that requires only body mass (not height, age, or sex) as input. Expert estimation of energy expenditure suggested a power-law relationship between mass and energy. A similar mass-energy expenditure relationship was derived from published pediatric echocardiographic data using a Monte Carlo model of energy expenditure based on oxygen delivery and consumption. A simplified form of the equation was compared with energy required for normal growth in a cohort of historical patients weighing 2 to 70 kg. All 3 methods demonstrate that variation in energy expenditure in children is dominated by mass and can be estimated by the following equation: Power(kcal/kg/d) = 200 × [Mass(kg)(−0.4)]. This relationship explains 85% of the variability in energy required to maintain expected growth over a broad range of surgical clinical contexts. A simplified power-law equation predicts real-world energy needs for growth in patients over a wide range of body sizes and clinical contexts, providing a more useful bedside tool than traditional estimators. PMID:22308194

  6. Allometric patterns of cranial bone thickness in fossil hominids.

    PubMed

    Gauld, S C

    1996-07-01

    The interspecific allometry of five measures of total cranial bone thickness is examined in 10 extant catarrhine genera and two fossil hominid samples representing A. africanus and Asian H. erectus. Analysis of the modern sample shows that most interspecific variation in vault thickness can be accounted for by variation in body size. Correlation values are moderate to high (r = 0.75-0.98), and all variables exhibit positive allometry. The bone thickness: body mass relationship of modern humans broadly conforms with that of other primates. However, in the distribution of relative thickness throughout the skull, H. sapiens is distinguished by relative thickening of the parietal and extreme relative thinning of the temporal squama. The bone thickness: body mass relationship in the two early hominid species is examined using published mean body weight estimates generated from post-cranial predictor variables. A. africanus exhibits great similarity to modern humans in its relation to the catarrhine regression data and in the distribution of relative thickness throughout the skull. H. erectus also shows a modern human-like pattern in the distribution of its relative thickness; however, its bone thickness: body mass relationship is dissimilar to that displayed by all other taxa, including the other hominid species. On the basis of these results, it is suggested that the published body weight estimate assigned to H. erectus greatly underestimates actual mean body size for Asian members of this species. PMID:8798997

  7. Computational Study of the Scaling relationship between Fluid Flow and Fracture Stiffness

    NASA Astrophysics Data System (ADS)

    Petrovitch, C.; Pyrak-Nolte, L. J.; Nolte, D.

    2008-12-01

    To sequester CO2 in the subsurface requires an understanding of the relationships among physical processes that occur on multiple length and time scales. If seismic techniques are to be developed to monitor the injection and containment phases of CO2 sequestration, it is important to understand not only how the microscopic behavior affects macroscopic measurements, but to determine how measurements made on the laboratory scale may be relevant to the field scale. We performed a computational study to investigate the scaling behavior of the interrelationship between the fracture specific stiffness and fluid flow through fractures to promote development of active seismic monitoring techniques to quantify the time-dependent changes in a subsurface CO2 reservoir. The relationship between the hydraulic and seismic properties of fractures is based on the empirical relationship between fluid flow through a fracture and fracture specific stiffness. Experimental work has shown that fracture stiffness and fluid flow through a fracture both depend on the topology of the fracture. In our study, we focus on the role of fracture in expressing the fracture stiffness - flow fluid relationship in scaling form. The geometry of fractures were simulated using stratified continuum percolation that constructs a hierarchical aperture distribution with a tunable spatial correlation length. Correlation lengths were varied from a quarter of the fracture length to the full length of the fracture. The dimensions of the fractures ranged from 1024 to 32 pixels (1 m to 0.03 m) to observe scaling behavior. The spatial and size distribution of the aperture and contact area for each simulated fracture were quantified along with percolation probabilities, percolation cluster statistics and other geometric parameters. The fracture specific stiffness was determined using an algorithm that models the asperities of the fracture surface on a regular lattice grid. The half-spaces and asperities deformed

  8. Early development and allometric growth patterns of the grumatã (Prochilodus vimboides Kner, 1859).

    PubMed

    Souza, Guilherme; Melo, Edésio J T; Caramaschi, Erica P; Andrade, Dalcio R; Monteiro, Leandro R

    2016-06-01

    The objective of this study was to characterize the early development and allometric growth of the grumatã (Prochilodus vimboides). We describe a sample of 266 eggs and larvae obtained through induced spawning. The eggs were spherical (mean 3.7 mm diameter), exhibited a yellow yolk and were non-adhesive and pelagic after fertilization and hydration. The time elapsed between the early cleavage and post-flexion stages was considered short (328 hours, 8054 hour-degrees) in regard to the development times of other Neotropical rheophilic species, but time to hatching was considerably longer than in other Prochilodus species. The most notable anatomical changes were observed between the end of the yolk larval stage and the beginning of the pre-flexion stage, when the larvae displayed directed swimming and the digestive system became functional, enabling the transition from endogenous to exogenous feeding. After hatching, the larvae grew from 6.04 to 15.15 mm in total length average. Two growth phases were observed at this stage: a non-linear asymptotic curve in yolk-sac larvae, and a linear constant-rate growth phase after exogenous feeding started. Allometric growth related to standard length was positive for head length, negative for eye diameter, and switched between phases from negative to positive in body depth and head height. Morphological development and allometric growth in different larval phases impose drastic anatomical and physiological changes that are synchronic with habitat changes and the flood cycles during the reproductive period. PMID:26199146

  9. Allometric Equations for Aboveground and Belowground Biomass Estimations in an Evergreen Forest in Vietnam

    PubMed Central

    Nam, Vu Thanh; van Kuijk, Marijke; Anten, Niels P. R.

    2016-01-01

    Allometric regression models are widely used to estimate tropical forest biomass, but balancing model accuracy with efficiency of implementation remains a major challenge. In addition, while numerous models exist for aboveground mass, very few exist for roots. We developed allometric equations for aboveground biomass (AGB) and root biomass (RB) based on 300 (of 45 species) and 40 (of 25 species) sample trees respectively, in an evergreen forest in Vietnam. The biomass estimations from these local models were compared to regional and pan-tropical models. For AGB we also compared local models that distinguish functional types to an aggregated model, to assess the degree of specificity needed in local models. Besides diameter at breast height (DBH) and tree height (H), wood density (WD) was found to be an important parameter in AGB models. Existing pan-tropical models resulted in up to 27% higher estimates of AGB, and overestimated RB by nearly 150%, indicating the greater accuracy of local models at the plot level. Our functional group aggregated local model which combined data for all species, was as accurate in estimating AGB as functional type specific models, indicating that a local aggregated model is the best choice for predicting plot level AGB in tropical forests. Finally our study presents the first allometric biomass models for aboveground and root biomass in forests in Vietnam. PMID:27309718

  10. Allometric Equations for Aboveground and Belowground Biomass Estimations in an Evergreen Forest in Vietnam.

    PubMed

    Nam, Vu Thanh; van Kuijk, Marijke; Anten, Niels P R

    2016-01-01

    Allometric regression models are widely used to estimate tropical forest biomass, but balancing model accuracy with efficiency of implementation remains a major challenge. In addition, while numerous models exist for aboveground mass, very few exist for roots. We developed allometric equations for aboveground biomass (AGB) and root biomass (RB) based on 300 (of 45 species) and 40 (of 25 species) sample trees respectively, in an evergreen forest in Vietnam. The biomass estimations from these local models were compared to regional and pan-tropical models. For AGB we also compared local models that distinguish functional types to an aggregated model, to assess the degree of specificity needed in local models. Besides diameter at breast height (DBH) and tree height (H), wood density (WD) was found to be an important parameter in AGB models. Existing pan-tropical models resulted in up to 27% higher estimates of AGB, and overestimated RB by nearly 150%, indicating the greater accuracy of local models at the plot level. Our functional group aggregated local model which combined data for all species, was as accurate in estimating AGB as functional type specific models, indicating that a local aggregated model is the best choice for predicting plot level AGB in tropical forests. Finally our study presents the first allometric biomass models for aboveground and root biomass in forests in Vietnam. PMID:27309718

  11. River channel width change: Dynamics and scaling relationships in the upper Midwestern US

    NASA Astrophysics Data System (ADS)

    Notebaert, Bastiaan; Belmont, Patrick; Donovan, Mitchell

    2016-04-01

    The width of alluvial river channels varies as a function of multiple variables, including flow, sediment supply, bed roughness and riparian vegetation. Changes in channel width are highly variable in space and time, but few have characterized and/or explained the structure and scaling relationships of that variability. Increasing availability of remote sensing data and computational power allows us to measure landscape changes at more detailed spatial and temporal scales than ever. In this study we use historic air photos to study patterns of channel width change and examine the effects data resolution on measurements of channel width change. We digitized 129 km of (vegetated) channel banks for the Root River in Minnesota, USA, for nearly every decade (excluding the 60s and 80s) spanning 1937-2013. Rates of channel widening were calculated at different spatial and temporal scales. Spatial-scaling effects were examined by measuring width changes from a 10-m window to the reach (~10 km) scale. The time interval between measurements varied from 1 year to 76 years. Data show that at small (100 m) spatial scales reaches that widen in one time period have a strong propensity to narrow in the following period. The most active reaches typically exhibit short, punctuated periods of change, but the stretches that are most active varied across decades. When increasing the temporal scale (time period) over which rates are calculated, the rates exhibit an apparent decrease, an effect that is observed for both the recent period and for data from the 1930s-50s. When considering the same time scale, rates are comparable for both periods. In addition to a temporal scaling effect there is also a spatial scaling effect. Changes in width are spatially correlated for distances up to a 3 to 5 times the channel width. Rates measured over shorter stretches are higher than those measured for longer ones. The most extreme changes occurred over shorter time periods along reaches with a

  12. Global-Scale Relationships between Colonization Ability and Range Size in Marine and Freshwater Fish

    PubMed Central

    Strona, Giovanni; Galli, Paolo; Montano, Simone; Seveso, Davide; Fattorini, Simone

    2012-01-01

    Although fish range sizes are expected to be associated with species dispersal ability, several studies failed to find a clear relationship between range size and duration of larval stage as a measure of dispersal potential. We investigated how six characteristics of the adult phase of fishes (maximum body length, growth rate, age at first maturity, life span, trophic level and frequency of occurrence) possibly associated with colonization ability correlate with range size in both freshwater and marine species at global scale. We used more than 12 million point records to estimate range size of 1829 freshwater species and 10068 marine species. As measures of range size we used both area of occupancy and extent of occurrence. Relationships between range size and species traits were assessed using Canonical Correlation Analysis. We found that frequency of occurrence and maximum body length had a strong influence on range size measures, which is consistent with patterns previously found (at smaller scales) in several other taxa. Freshwater and marine fishes showed striking similarities, suggesting the existence of common mechanisms regulating fish biogeography in the marine and freshwater realms. PMID:23185338

  13. The scaling relationship between self-potential and fluid flow on Masaya volcano, Nicaragua

    SciTech Connect

    Lewicki, J.L.; Hilley, G.E.; Conner, C.

    2003-11-11

    The concurrent measurement of self-potential (SP) and soil CO{sub 2} flux (F{sub s}{sup CO2}) in volcanic systems may be an important tool to monitor intrusive activity and understand interaction between magmatic and groundwater systems. However, quantitative relationships between these parameters must be established to apply them toward understanding processes operating at depth. Power-law scaling exponents calculated for SP and F{sub s}{sup CO2} measured along a fault on the flanks of Masaya volcano, Nicaragua indicate a nonlinear relationship between these parameters. Scaling exponents suggest that there is a declining increase in SP with a given increase in F{sub s}{sup CO2}, until a threshold (log F{sub s}{sup CO2} {approx} 2.5 g m{sup -2}d{sup -1}) above which SP remains constant with increasing F{sub s}{sup CO2}. Implications for subsurface processes that may influence SP at Masaya are discussed.

  14. Global-scale relationships between colonization ability and range size in marine and freshwater fish.

    PubMed

    Strona, Giovanni; Galli, Paolo; Montano, Simone; Seveso, Davide; Fattorini, Simone

    2012-01-01

    Although fish range sizes are expected to be associated with species dispersal ability, several studies failed to find a clear relationship between range size and duration of larval stage as a measure of dispersal potential. We investigated how six characteristics of the adult phase of fishes (maximum body length, growth rate, age at first maturity, life span, trophic level and frequency of occurrence) possibly associated with colonization ability correlate with range size in both freshwater and marine species at global scale. We used more than 12 million point records to estimate range size of 1829 freshwater species and 10068 marine species. As measures of range size we used both area of occupancy and extent of occurrence. Relationships between range size and species traits were assessed using Canonical Correlation Analysis. We found that frequency of occurrence and maximum body length had a strong influence on range size measures, which is consistent with patterns previously found (at smaller scales) in several other taxa. Freshwater and marine fishes showed striking similarities, suggesting the existence of common mechanisms regulating fish biogeography in the marine and freshwater realms. PMID:23185338

  15. Towards a refinement of the D-L fault scale relationship for Mercury using MESSENGER topography

    NASA Astrophysics Data System (ADS)

    Di Achille, G.; Popa, C.; Galluzzi, V.; Ferranti, L.; Zusi, M.; Palumbo, P.

    2013-09-01

    Terrestrial faults show that the maximum displacement along the fault plane (D) scales with the plan-view length of the fault (L) [e.g., 1]. Particularly, it has been proposed that the latter relationship can be simplified to a linear relationship D=γ L (1) where γ is a constant depending on the lithology and overall tectonic context [1]. The linear relationship seems to be also applicable for planetary faults [e.g. 2, 3] and it is one of the few tools commonly used for estimating fault shortening and thus the amount of global planetary contraction for Mercury [4-7]. The ratio of D to L (i.e. γ) strongly affects the resulting estimates of shortening, therefore, the accuracy of γ is fundamental for quantitative tectonic studies based on (1). The coverage and resolution of topographic datasets are crucial for calculating γ. Prior to the MESSENGER mission, γ for Mercury's lobate scarps and wrinkle ridges were defined using the topography obtained from Mariner 10 images and radar observations from Arecibo [e.g. 4, 5]. Here we present preliminary results of a refinement of γ based on a survey of compressional tectonic structure throughout 30% of the Mercury's surface using topography derived from MESSENGER data. Our preliminary results suggest that γ values derived and used in previous studies [5-7] were likely overestimated and could have then resulted in a overestimation of fault shortening and global planetary contraction.

  16. Species-environment relationships and vegetation patterns: Effects of spatial scale and tree life-stage

    USGS Publications Warehouse

    Stohlgren, T.J.; Bachand, R.R.; Onami, Y.; Binkley, D.

    1998-01-01

    Do relationships between species and environmental gradients strengthen or weaken with tree life-stage (i.e., small seedlings, large seedlings, saplings, and mature trees)? Strengthened relationships may lead to distinct forest type boundaries, or weakening connections could lead to gradual ecotones and heterogeneous forest landscapes. We quantified the changes in forest dominance (basal area of tree species by life-stage) and environmental factors (elevation, slope, aspect, intercepted photosynthetically active radiation (PAR), summer soil moisture, and soil depth and texture) across 14 forest ecotones (n = 584, 10 m x 10 m plots) in Rocky Mountain National Park, Colorado, U.S.A. Local, ecotone-specific species-environment relationships, based on multiple regression techniques, generally strengthened from the small seedling stage (multiple R2 ranged from 0.00 to 0.26) to the tree stage (multiple R2 ranged from 0.20 to 0.61). At the landscape scale, combined canonical correspondence analysis (CCA) among species and for all tree life-stages suggested that the seedlings of most species became established in lower-elevation, drier sites than where mature trees of the same species dominated. However, conflicting evidence showed that species-environment relationships may weaken with tree life-stage. Seedlings were only found in a subset of plots (habitats) occupied by mature trees of the same species. At the landscape scale, CCA results showed that species-environment relationships weakened somewhat from the small seedling stage (86.4% of the variance explained by the first two axes) to the tree stage (76.6% of variance explained). The basal area of tree species co-occurring with Pinus contorta Doug. ex. Loud declined more gradually than P. contorta basal area declined across ecotones, resulting in less-distinct forest type boundaries. We conclude that broad, gradual ecotones and heterogeneous forest landscapes are created and maintained by: (1) sporadic establishment

  17. The Relationship of MacAndrew Alcoholism Scale Scores to MMPI Profile Type and Degree of Elevation.

    ERIC Educational Resources Information Center

    Pfost, Karen S.; And Others

    1984-01-01

    Investigated the relationship of the MacAndrew Alcoholism Scale (MAC) to personality type and level of emotional distress using Minnesota Multiphasic Personality Inventory scores of 38 alcoholic males. No relationship was found between the MAC and magnitude of psychological distress, as measured by T scores. (JAC)

  18. A common genetic basis to the origin of the leaf economics spectrum and metabolic scaling allometry.

    PubMed

    Vasseur, François; Violle, Cyrille; Enquist, Brian J; Granier, Christine; Vile, Denis

    2012-10-01

    Many facets of plant form and function are reflected in general cross-taxa scaling relationships. Metabolic scaling theory (MST) and the leaf economics spectrum (LES) have each proposed unifying frameworks and organisational principles to understand the origin of botanical diversity. Here, we test the evolutionary assumptions of MST and the LES using a cross of two genetic variants of Arabidopsis thaliana. We show that there is enough genetic variation to generate a large fraction of variation in the LES and MST scaling functions. The progeny sharing the parental, naturally occurring, allelic combinations at two pleiotropic genes exhibited the theorised optimum ¾ allometric scaling of growth rate and intermediate leaf economics. Our findings: (1) imply that a few pleiotropic genes underlie many plant functional traits and life histories; (2) unify MST and LES within a common genetic framework and (3) suggest that observed intermediate size and longevity in natural populations originate from stabilising selection to optimise physiological trade-offs. PMID:22856883

  19. Scaling relationship for source parameters of the seismicity of the Corinth Rift (Greece)

    NASA Astrophysics Data System (ADS)

    Matrullo, Emanuela; Satriano, Claudio; Lyon-Caen, Helene; Bernard, Pascal; Deschamps, Anne; Papadimitriou, Panayotis; Sokos, Efthimios; Plicka, Vladimir

    2013-04-01

    The improvements in high-density, high-dynamics and broadband seismic observation make it possible to investigate the proprieties of microearthquake source parameters at very small scales, in order to better understand the earthquake process similarity over a broad magnitude range. The issue of earthquake source scaling continues to draw considerable debate within the seismological community: both supporting and refuting that systematic differences between the source processes of small and large earthquakes may exist. It motivates the study of how source parameters, such as seismic moment, corner frequency, radiated seismic energy, and apparent stress, scale over a wide range of magnitudes. On the other hand the estimation of the heterogeneous distribution of seismic attenuation from the dispersion of amplitude with frequency is important for the characterization of rock and fluid properties, e.g., saturation, porosity, permeability, and viscosity, because attenuation is more sensitive than velocity to some of these properties. To address these questions, we analyze the seismicity recorded from 2000 to 2011 by the Corinth Rift Laboratory european project (http:/crlab.eu) covering the western part of the Corinth Rift (Greece). The network was composed in 2000 of 12 recording stations, with short period three component seismometers. Over the years 6 broadband stations have been added. The Corinth Rift (Western Greece) is one of the most seismic active area in Europe with several instrumental and historical earthquakes (at least 5 earthquakes with magnitude larger than 5.8 in the last 35 years), several seismic swarms and significant background seismicity. The database consists in about 100,000 events with prevalent normal faulting focal mechanism and covers five orders of magnitude of seismic moment M0 (10^10 - 10^15 Nm). We investigate scaling relationships of the source parameters from S-wave signals. We use a frequency domain parametric approach to estimate

  20. Outer scale and Monin-Obukhov flux relationships of atmospheric turbulence under dry convective conditions

    NASA Astrophysics Data System (ADS)

    De Bruin, Henk; Hartogensis, Oscar

    2015-04-01

    In this study we will investigate the assumption that in the atmospheric surface layer the outer scale (L0) is proportional to the height above the surface, under dry convective conditions. For this purpose we analyzed raw sonic anemometers data collected at 3.5 m and at 9 m in a field campaign at the Santa Cruz Flats (32040.3190'N, 111032.641'W, 526 m of elevation) near Eloy, Arizona. For simplicity, we define the L0 as that separation distance at which the spatial correlation coefficient of air temperature at two points in the surface layer is 0.5. Then, according to the 2/3-Kolmogorov scaling law in the inertial sub-range, L0 is determined by the variance and the structure parameter of T . It is found that L0 does not scale with height. Possible reasons for this negative result will be discussed, by considering the methodology to determine structure parameters, Taylor's frozen turbulence hypothesis, effects of intermittency and Monin-Obukhov flux relationships for variance and structure parameter for T . The question is asked whether the concept of surface constant flux layer still holds under strong convective condition.

  1. Quantifying the relationships between precipitation and atmospheric radiative cooling on a range of scales

    NASA Astrophysics Data System (ADS)

    Naegele, A. C.; Randall, D. A.

    2014-12-01

    In the global energy budget, the radiative cooling of the atmosphere is approximately balanced by latent heating; this implies a positive temporal correlation between the globally averaged atmospheric radiative cooling rate (ARC) and the globally averaged precipitation rate. The high clouds associated with precipitating weather systems tend to reduce the ARC, and so act to damp fluctuations of the global hydrologic cycle. In contrast, on the regional scale, high clouds cause the precipitation rate and the ARC to be negatively correlated in both space and time. The radiative warming associated with the high clouds promotes regional-scale rising motion and so feeds back to enhance the regional precipitation rate. We have used precipitation data from the Global Precipitation Climatology Project and radiative flux data (used to calculate the ARC) from the Clouds and the Earth's Radiant Energy System (CERES) project to investigate the relationships between the ARC and the precipitation rate on a range of spatial and temporal scales. Results show that the ARC and the precipitation rate are positively correlated globally and in middle and high latitudes, and negatively correlated in the tropics.

  2. Universal species-area and endemics-area relationships at continental scales.

    PubMed

    Storch, David; Keil, Petr; Jetz, Walter

    2012-08-01

    Despite the broad conceptual and applied relevance of how the number of species or endemics changes with area (the species-area and endemics-area relationships (SAR and EAR)), our understanding of universality and pervasiveness of these patterns across taxa and regions has remained limited. The SAR has traditionally been approximated by a power law, but recent theories predict a triphasic SAR in logarithmic space, characterized by steeper increases in species richness at both small and large spatial scales. Here we uncover such universally upward accelerating SARs for amphibians, birds and mammals across the world’s major landmasses. Although apparently taxon-specific and continent-specific, all curves collapse into one universal function after the area is rescaled by using the mean range sizes of taxa within continents. In addition, all EARs approximately follow a power law with a slope close to 1, indicating that for most spatial scales there is roughly proportional species extinction with area loss. These patterns can be predicted by a simulation model based on the random placement of contiguous ranges within a domain. The universality of SARs and EARs after rescaling implies that both total and endemic species richness within an area, and also their rate of change with area, can be estimated by using only the knowledge of mean geographic range size in the region and mean species richness at one spatial scale. PMID:22722856

  3. Spatial disaggregation of complex soil map units at regional scale based on soil-landscape relationships

    NASA Astrophysics Data System (ADS)

    Vincent, Sébastien; Lemercier, Blandine; Berthier, Lionel; Walter, Christian

    2015-04-01

    Accurate soil information over large extent is essential to manage agronomical and environmental issues. Where it exists, information on soil is often sparse or available at coarser resolution than required. Typically, the spatial distribution of soil at regional scale is represented as a set of polygons defining soil map units (SMU), each one describing several soil types not spatially delineated, and a semantic database describing these objects. Delineation of soil types within SMU, ie spatial disaggregation of SMU allows improved soil information's accuracy using legacy data. The aim of this study was to predict soil types by spatial disaggregation of SMU through a decision tree approach, considering expert knowledge on soil-landscape relationships embedded in soil databases. The DSMART (Disaggregation and Harmonization of Soil Map Units Through resampled Classification Trees) algorithm developed by Odgers et al. (2014) was used. It requires soil information, environmental covariates, and calibration samples, to build then extrapolate decision trees. To assign a soil type to a particular spatial position, a weighed random allocation approach is applied: each soil type in the SMU is weighted according to its assumed proportion of occurrence in the SMU. Thus soil-landscape relationships are not considered in the current version of DSMART. Expert rules on soil distribution considering the relief, parent material and wetlands location were proposed to drive the procedure of allocation of soil type to sampled positions, in order to integrate the soil-landscape relationships. Semantic information about spatial organization of soil types within SMU and exhaustive landscape descriptors were used. In the eastern part of Brittany (NW France), 171 soil types were described; their relative area in the SMU were estimated, geomorphological and geological contexts were recorded. The model predicted 144 soil types. An external validation was performed by comparing predicted

  4. Contaminant Load-Discharge Relationships Across Scales in Engineered Watersheds: Order Out of Complexity

    NASA Astrophysics Data System (ADS)

    Rao, P. S. C.; Basu, N. B.; Zanardo, S.; Botter, G.; Rinaldo, A.

    2009-04-01

    Lagrangian Model), to predict observed event hydrographs and chemographs for four crop growing seasons. TELM predictions, requiring no calibration for model parameters, were in good agreement with the measured event hydrographs and chemographs. TELM model was further tested by comparing predicted event hydrographs and event chemographs measured in the Little Vermillion River watershed (~300 km^2) in Illinois, USA. Next, TELM model outputs were linked to a distributed stream network model, based on Lagrangian travel time distributions, to predict the spatial patterns in nutrient delivery ratios at multiple spatial scales across the watersheds. Furthermore, we examined the hydrologic and water-quality monitoring data available for the Mississippi River Basin, and found consistent linear relationships between area-normalized annual discharge (Q; L^3L^-2T^-1) and area-normalized annual nutrient loads (ML-2T-1) at all spatial scales, ranging from first-order watersheds (~10 to 100 km^2) to the entire river basin (~3x106 km^2), and offer a theoretical explanation. By comparing the load-discharge data for conservative constituents (e.g., bicarbonate) with that for more-reactive constituents (nitrate, phosphate, pesticides), we estimated the effective nutrient attenuation rate constants (ke, T^-1) at each spatial scale. Finally, we derived explicit analytical expressions for reproducing the reported ke scale-dependence. Implications of these results to watershed management strategies aimed at mitigating adverse water-quality impacts of nutrient loads are discussed.

  5. Measuring the Closeness of Relationships: A Comprehensive Evaluation of the 'Inclusion of the Other in the Self' Scale

    PubMed Central

    2015-01-01

    Understanding the nature and influence of social relationships is of increasing interest to behavioral economists, and behavioral scientists more generally. In turn, this creates a need for tractable, and reliable, tools for measuring fundamental aspects of social relationships. We provide a comprehensive evaluation of the 'Inclusion of the Other in the Self' (IOS) Scale, a handy pictorial tool for measuring the subjectively perceived closeness of a relationship. The tool is highly portable, very easy for subjects to understand and takes less than 1 minute to administer. Across our three online studies with a diverse adult population (n = 772) we show that six different scales designed to measure relationship closeness are all highly significantly positively correlated with the IOS Scale. We then conduct a Principal Component Analysis to construct an Index of Relationship Closeness and find that it correlates very strongly (ρ = 85) with the IOS Scale. We conclude that the IOS Scale is a psychologically meaningful and highly reliable measure of the subjective closeness of relationships. PMID:26068873

  6. Scaling of the flow-stiffness relationship in weakly correlated single fractures

    NASA Astrophysics Data System (ADS)

    Petrovitch, Christopher L.

    The remote characterization of the hydraulic properties of fractures in rocks is important in many subsurface projects. Fractures create uncertainty in the hydraulic properties of the subsurface in that their topology controls the amount of flow that can occur in addition to that from the matrix. In turn, the fracture topology is also affected by stress which alters the topology as the stress changes directly. This alteration of fracture topology with stress is captured by fracture specific stiffness. The specific stiffness of a single fracture can be remotely probed from the attenuation and velocity of seismic waves. The hydromechanical coupling of single fractures, i.e. the relationship between flow and stiffness, holds the key to finding a method to remotely characterize a fractures hydraulic properties. This thesis is separated into two parts: (1) a description of the hydromechanical coupling of fractures based on numerical models used to generate synthetic fractures, compute the flow through a fracture, and deform fracture topologies to unravel the scaling function that is fundamental to the hydromechanical coupling of single fractures; (2) a Discontinuous Galerkin (DG) method was developed to accurately simulate the scattered seismic waves from realistic fracture topologies. The scaling regimes of fluid flow and specific stiffness in weakly correlated fractures are identified by using techniques from Percolation Theory and initially treating the two processes separately. The fixed points associated with fluid flow were found to display critical scaling while the fixed points for specific stiffness were trivial. The two processes could be indirectly related because the trivial scaling of the mechanical properties allowed the specific stiffness to be used as surrogate to the void area fraction. The dynamic transport exponent was extracted at threshold by deforming fracture geometries within the effective medium regime (near the ``cubic law'' regime) to the

  7. Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes

    NASA Astrophysics Data System (ADS)

    Passarelli, Luigi; Rivalta, Eleonora; Shuler, Ashley

    2014-05-01

    Rifting episodes accommodate the relative motion of mature divergent plate boundaries with sequences of magma-filled dikes that compensate for the missing volume due to crustal splitting. Two major rifting episodes have been recorded since modern monitoring techniques are available: the 1975-1984 Krafla (Iceland) and the 2005-2010 Manda-Hararo (Ethiopia) dike sequences. The statistical properties of the frequency of dike intrusions during rifting have never been investigated in detail, but it has been suggested that they may have similarities with earthquake mainshock-aftershock sequences, for example they start with a large intrusion followed by several events of smaller magnitude. The scaling relationships of earthquakes have on the contrary been widely investigated: earthquakes have been found to follow a power law, the Gutenberg-Richter relation, from local to global scale, while the decay of aftershocks with time has been found to follow the Omori law. These statistical laws for earthquakes are the basis for hazard evaluation and the physical mechanisms behind them are the object of wide interest and debate. Here we investigate in detail the statistics of dikes from the Krafla and Manda-Hararo rifting episodes, including their frequency-magnitude distribution, the release of geodetic moment in time, the correlation between interevent times and intruded volumes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, the long-term release of geodetic moment is governed by a relationship consistent with the Omori law, and the intrusions are roughly time-predictable. The need of magma availability affects however the timing of secondary dike intrusions: such timing is longer after large volume intrusions, contrarily to aftershock sequences where interevent times shorten after large events.

  8. Relationships Among the Edwards Personality Inventory Scales, the Edwards Personality Preference Schedule, and the Personality Research Form Scales

    ERIC Educational Resources Information Center

    Edwards, Allen L.; Abbott, Robert D.

    1973-01-01

    The present study was undertaken to determine the degree to which the EPPS and PRF scales are correlated with the EPI scales, and also to determine the degree to which the scales in all three inventories are measuring the same common traits. (Author)

  9. Mechanical and energetic scaling relationships of running gait through ontogeny in the ostrich (Struthio camelus).

    PubMed

    Smith, Nicola C; Wilson, Alan M

    2013-03-01

    It is unclear whether small animals, with their high stride frequency and crouched posture, or large animals, with more tendinous limbs, are more reliant on storage and return of elastic energy during locomotion. The ostrich has a limb structure that appears to be adapted for high-speed running with long tendons and short muscle fibres. Here we investigate biomechanics of ostrich gait through growth and, with consideration of anatomical data, identify scaling relationships with increasing body size, relating to forces acting on the musculoskeletal structures, effective mechanical advantage (EMA) and mechanical work. Kinematic and kinetic data were collected through growth from running ostriches. Joint moments scaled in a similar way to the pelvic limb segments as a result of consistent posture through growth, such that EMA was independent of body mass. Because no postural change was observed, relative loads applied to musculoskeletal tissues would be predicted to increase during growth, with greater muscle, and hence tendon, load allowing increased potential for elastic energy storage with increasing size. Mass-specific mechanical work per unit distance was independent of body mass, resulting in a small but significant increase in the contribution of elastic energy storage to locomotor economy in larger ostriches. PMID:23155079

  10. The Budyko and complementary relationships in an idealized model of large-scale land-atmosphere coupling

    NASA Astrophysics Data System (ADS)

    Lintner, B. R.; Gentine, P.; Findell, K. L.; Salvucci, G.

    2014-12-01

    Expressions corresponding to two well-known relationships in hydrology and hydrometeorology, the Budyko and complementary relationships, are derived within an idealized prototype representing the physics of large-scale land-atmosphere coupling. These relationships are shown to hold on long (climatologic) time scales because of the tight coupling that exists between precipitation, atmospheric radiation, moisture convergence and advection. The slope of the complementary relationship is shown to be dependent the Clausius-Clapeyron relationship between saturation specific humidity and temperature, with important implications for the continental hydrologic cycle in a warming climate, e.g., one consequence of this dependence is that the complementary relationship may be expected to become more asymmetric with warming, as higher values of the slope imply a larger change in potential evaporation for a given change in evapotranspiration. In addition, the transparent physics of the prototype permits diagnosis of the sensitivity of the Budyko and complementary relationships to various atmospheric and land surface processes. Here, the impacts of anthropogenic influences, including large-scale irrigation and global warming, are assessed.

  11. Relationship Quality and Patient-Assessed Quality of Care in VA Primary Care Clinics: Development and Validation of the Work Relationships Scale

    PubMed Central

    Finley, Erin P.; Pugh, Jacqueline A.; Lanham, Holly Jordan; Leykum, Luci K.; Cornell, John; Veerapaneni, Poornachand; Parchman, Michael L.

    2013-01-01

    PURPOSE Efforts to better understand the impact of clinic member relationships on care quality in primary care clinics have been limited by the absence of a validated instrument to assess these relationships. The purpose of this study was to develop and validate a scale assessing relationships within primary care clinics. METHODS The Work Relationships Scale (WRS) was developed and administered as part of a survey of learning and relationships among 17 Department of Veterans Affairs (VA) primary care clinics. A Rasch partial-credit model and principal components analysis were used to evaluate item performance, select the final items for inclusion, and establish unidimensionality for the WRS. The WRS was then validated against semistructured clinic member interviews and VA Survey of Healthcare Experiences of Patients (SHEP) data. RESULTS Four hundred fifty-seven clinicians and staff completed the clinic survey, and 247 participated in semistructured interviews. WRS scores were significantly associated with clinic-level reporting for 2 SHEP variables: overall rating of personal doctor/nurse (r2 =0.43, P <.01) and overall rating of health care (r2= 0.25, P <.05). Interview data describing relationship characteristics were consistent with variability in WRS scores across low-scoring and high-scoring clinics. CONCLUSIONS The WRS shows promising validity as a measure assessing the quality of relationships in primary care settings; moreover, primary care clinics with lower WRS scores received poorer patient quality ratings for both individual clinicians and overall health care. Relationships play an important role in shaping care delivery and should be assessed as part of efforts to improve patient care within primary care settings. PMID:24218378

  12. Understanding the Construct of Self-Determination: Examining the Relationship between the Arc's Self-Determination Scale and the American Institutes for Research Self-Determination Scale

    ERIC Educational Resources Information Center

    Shogren, Karrie A.; Wehmeyer, Michael L.; Palmer, Susan B.; Soukup, Jane Helen; Little, Todd D.; Garner, Nancy; Lawrence, Margaret

    2008-01-01

    Since the early 1990s, attention has been focused on the importance of self-determination in the education of students with disabilities. The purpose of this study was to further our understanding of the construct of self-determination by examining the relationship between the "Arc's Self-Determination Scale" and the "American Institutes for…

  13. Estimating geographic variation on allometric growth and body condition of Blue Suckers with quantile regression

    USGS Publications Warehouse

    Cade, B.S.; Terrell, J.W.; Neely, B.C.

    2011-01-01

    Increasing our understanding of how environmental factors affect fish body condition and improving its utility as a metric of aquatic system health require reliable estimates of spatial variation in condition (weight at length). We used three statistical approaches that varied in how they accounted for heterogeneity in allometric growth to estimate differences in body condition of blue suckers Cycleptus elongatus across 19 large-river locations in the central USA. Quantile regression of an expanded allometric growth model provided the most comprehensive estimates, including variation in exponents within and among locations (range = 2.88–4.24). Blue suckers from more-southerly locations had the largest exponents. Mixed-effects mean regression of a similar expanded allometric growth model allowed exponents to vary among locations (range = 3.03–3.60). Mean relative weights compared across selected intervals of total length (TL = 510–594 and 594–692 mm) in a multiplicative model involved the implicit assumption that allometric exponents within and among locations were similar to the exponent (3.46) for the standard weight equation. Proportionate differences in the quantiles of weight at length for adult blue suckers (TL = 510, 594, 644, and 692 mm) compared with their average across locations ranged from 1.08 to 1.30 for southern locations (Texas, Mississippi) and from 0.84 to 1.00 for northern locations (Montana, North Dakota); proportionate differences for mean weight ranged from 1.13 to 1.17 and from 0.87 to 0.95, respectively, and those for mean relative weight ranged from 1.10 to 1.18 and from 0.86 to 0.98, respectively. Weights for fish at longer lengths varied by 600–700 g within a location and by as much as 2,000 g among southern and northern locations. Estimates for the Wabash River, Indiana (0.96–1.07 times the average; greatest increases for lower weights at shorter TLs), and for the Missouri River from Blair, Nebraska, to Sioux City, Iowa (0.90

  14. Efficacy of generic allometric equations for estimating biomass: a test in Japanese natural forests.

    PubMed

    Ishihara, Masae I; Utsugi, Hajime; Tanouchi, Hiroyuki; Aiba, Masahiro; Kurokawa, Hiroko; Onoda, Yusuke; Nagano, Masahiro; Umehara, Toru; Ando, Makoto; Miyata, Rie; Hiura, Tsutom

    2015-07-01

    Accurate estimation of tree and forest biomass is key to evaluating forest ecosystem functions and the global carbon cycle. Allometric equations that estimate tree biomass from a set of predictors, such as stem diameter and tree height, are commonly used. Most allometric equations are site specific, usually developed from a small number of trees harvested in a small area, and are either species specific or ignore interspecific differences in allometry. Due to lack of site-specific allometries, local equations are often applied to sites for which they were not originally developed (foreign sites), sometimes leading to large errors in biomass estimates. In this study, we developed generic allometric equations for aboveground biomass and component (stem, branch, leaf, and root) biomass using large, compiled data sets of 1203 harvested trees belonging to 102 species (60 deciduous angiosperm, 32 evergreen angiosperm, and 10 evergreen gymnosperm species) from 70 boreal, temperate, and subtropical natural forests in Japan. The best generic equations provided better biomass estimates than did local equations that were applied to foreign sites. The best generic equations included explanatory variables that represent interspecific differences in allometry in addition to stem diameter, reducing error by 4-12% compared to the generic equations that did not include the interspecific difference. Different explanatory variables were selected for different components. For aboveground and stem biomass, the best generic equations had species-specific wood specific gravity as an explanatory variable. For branch, leaf, and root biomass, the best equations had functional types (deciduous angiosperm, evergreen angiosperm, and evergreen gymnosperm) instead of functional traits (wood specific gravity or leaf mass per area), suggesting importance of other traits in addition to these traits, such as canopy and root architecture. Inclusion of tree height in addition to stem diameter improved

  15. Psychometric properties of an Italian version of the Experiences in Close Relationships-Revised (ECR-R) Scale.

    PubMed

    Busonera, Alessandra; Martini, Pietro San; Zavattini, Giulio Cesare; Santona, Alessandra

    2014-06-01

    This study examined the psychometric properties of a newly translated Italian version of the Experiences in Close Relationships-Revised (ECR-R) Scale. The sample comprised 1,363 adults (906 women, 456 men, 1 unreported sex; ages 18-64 yr., M = 33.4, SD = 8.9; 84.4% reported being engaged in a romantic relationship, 9.4% declared being single), all living in Italy and speaking Italian as their first language. Exploratory and confirmatory factor analyses showed the expected bi-factorial (anxiety/avoidance) structure and a close correspondence between factors and scales. Test-retest and internal consistency reliabilities were adequate. Correlations with the Relationship Questionnaire, a categorical measure of attachment, and with the Dyadic Adjustment Scale were consistent with the theoretical relations among the constructs. The findings confirm the transcultural validity of the ECR-R. PMID:25074302

  16. Using mass scaling of movement cost and resource encounter rate to predict animal body size-population density relationships.

    PubMed

    Nilsen, Erlend B; Finstad, Anders G; Næsje, Tor F; Sverdrup-Thygeson, Anne

    2013-06-01

    The negative relationship between body mass and population abundance was documented decades ago and forms one of the most fundamental scaling-laws in ecology. However, current theory fails to capture observed variations and the subject continues to raise controversy. Here we unify empirically observed size-abundance relationships with theory, by incorporating allometries in resource encounter rate and metabolic costs of movements. Fractal geometry is used to quantify the underlying resources distributions. Our model predicts that in environments packed with resources, body mass to population abundance relationships is less negative than the commonly assumed -3/4 power law. When resources are more patchily distributed, we predict a more negative exponent. These predictions are consistent with empirical observations. The current research provides an important step towards synthesizing metabolism, resource distribution and the global scaling of animal abundance, explaining why size-abundance relationships vary among feeding guilds and ecosystems. PMID:23548840

  17. A unique cellular scaling rule in the avian auditory system.

    PubMed

    Corfield, Jeremy R; Long, Brendan; Krilow, Justin M; Wylie, Douglas R; Iwaniuk, Andrew N

    2016-06-01

    Although it is clear that neural structures scale with body size, the mechanisms of this relationship are not well understood. Several recent studies have shown that the relationship between neuron numbers and brain (or brain region) size are not only different across mammalian orders, but also across auditory and visual regions within the same brains. Among birds, similar cellular scaling rules have not been examined in any detail. Here, we examine the scaling of auditory structures in birds and show that the scaling rules that have been established in the mammalian auditory pathway do not necessarily apply to birds. In galliforms, neuronal densities decrease with increasing brain size, suggesting that auditory brainstem structures increase in size faster than neurons are added; smaller brains have relatively more neurons than larger brains. The cellular scaling rules that apply to auditory brainstem structures in galliforms are, therefore, different to that found in primate auditory pathway. It is likely that the factors driving this difference are associated with the anatomical specializations required for sound perception in birds, although there is a decoupling of neuron numbers in brain structures and hair cell numbers in the basilar papilla. This study provides significant insight into the allometric scaling of neural structures in birds and improves our understanding of the rules that govern neural scaling across vertebrates. PMID:26002617

  18. Assessing Weather-Yield Relationships in Rice at Local Scale Using Data Mining Approaches

    PubMed Central

    Delerce, Sylvain; Dorado, Hugo; Grillon, Alexandre; Rebolledo, Maria Camila; Prager, Steven D.; Patiño, Victor Hugo; Garcés Varón, Gabriel; Jiménez, Daniel

    2016-01-01

    Seasonal and inter-annual climate variability have become important issues for farmers, and climate change has been shown to increase them. Simultaneously farmers and agricultural organizations are increasingly collecting observational data about in situ crop performance. Agriculture thus needs new tools to cope with changing environmental conditions and to take advantage of these data. Data mining techniques make it possible to extract embedded knowledge associated with farmer experiences from these large observational datasets in order to identify best practices for adapting to climate variability. We introduce new approaches through a case study on irrigated and rainfed rice in Colombia. Preexisting observational datasets of commercial harvest records were combined with in situ daily weather series. Using Conditional Inference Forest and clustering techniques, we assessed the relationships between climatic factors and crop yield variability at the local scale for specific cultivars and growth stages. The analysis showed clear relationships in the various location-cultivar combinations, with climatic factors explaining 6 to 46% of spatiotemporal variability in yield, and with crop responses to weather being non-linear and cultivar-specific. Climatic factors affected cultivars differently during each stage of development. For instance, one cultivar was affected by high nighttime temperatures in the reproductive stage but responded positively to accumulated solar radiation during the ripening stage. Another was affected by high nighttime temperatures during both the vegetative and reproductive stages. Clustering of the weather patterns corresponding to individual cropping events revealed different groups of weather patterns for irrigated and rainfed systems with contrasting yield levels. Best-suited cultivars were identified for some weather patterns, making weather-site-specific recommendations possible. This study illustrates the potential of data mining for

  19. Assessing Weather-Yield Relationships in Rice at Local Scale Using Data Mining Approaches.

    PubMed

    Delerce, Sylvain; Dorado, Hugo; Grillon, Alexandre; Rebolledo, Maria Camila; Prager, Steven D; Patiño, Victor Hugo; Garcés Varón, Gabriel; Jiménez, Daniel

    2016-01-01

    Seasonal and inter-annual climate variability have become important issues for farmers, and climate change has been shown to increase them. Simultaneously farmers and agricultural organizations are increasingly collecting observational data about in situ crop performance. Agriculture thus needs new tools to cope with changing environmental conditions and to take advantage of these data. Data mining techniques make it possible to extract embedded knowledge associated with farmer experiences from these large observational datasets in order to identify best practices for adapting to climate variability. We introduce new approaches through a case study on irrigated and rainfed rice in Colombia. Preexisting observational datasets of commercial harvest records were combined with in situ daily weather series. Using Conditional Inference Forest and clustering techniques, we assessed the relationships between climatic factors and crop yield variability at the local scale for specific cultivars and growth stages. The analysis showed clear relationships in the various location-cultivar combinations, with climatic factors explaining 6 to 46% of spatiotemporal variability in yield, and with crop responses to weather being non-linear and cultivar-specific. Climatic factors affected cultivars differently during each stage of development. For instance, one cultivar was affected by high nighttime temperatures in the reproductive stage but responded positively to accumulated solar radiation during the ripening stage. Another was affected by high nighttime temperatures during both the vegetative and reproductive stages. Clustering of the weather patterns corresponding to individual cropping events revealed different groups of weather patterns for irrigated and rainfed systems with contrasting yield levels. Best-suited cultivars were identified for some weather patterns, making weather-site-specific recommendations possible. This study illustrates the potential of data mining for

  20. Relationship between climate extremes in Romania and their connection to large-scale air circulation

    NASA Astrophysics Data System (ADS)

    Barbu, Nicu; Ştefan, Sabina

    2015-04-01

    The aim of this paper is to investigate the connection between climate extremes (temperature and precipitation) in Romania and large-scale air circulation. Daily observational data of maximum air temperature and amount of precipitation for the period 1961-2010 were used to compute two seasonal indices associated with temperature and precipitation, quantifying their frequency, as follows: frequency of very warm days (FTmax90 ≥ 90th percentile), frequency of very wet days (FPp90; daily precipitation amount ≥ 90th percentile). Seasonally frequency of circulation types were calculated from daily circulation types determined by using two objective catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) from the COST733Action. Daily reanalysis data sets (sea level pressure, geopotential height at 925 and 500 hPa, u and v components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column) build up by NCEP/NCAR, with 2.5°/2.5° lat/lon spatial resolution, were used to determine the circulation types. In order to select the optimal domain size related to the FTmax90 and the FPp90, the explained variance (EV) has been used. The EV determines the relation between the variance among circulation types and the total variance of the variable under consideration. This method quantifies the discriminatory power of a classification. The relationships between climate extremes in Romania and large-scale air circulation were investigated by using multiple linear regression model (MLRM), the predictands are FTmax90 and FPp90 and the circulation types were used as predictors. In order to select the independent predictors to build the MLRM the collinearity and multicollinearity analysis were performed. The study period is dividend in two periods: the period 1961-2000 is used to train the MLRM and the period 2001-2010 is used to validate the MLRM. The analytical relationship obtained by using MLRM can be used for future projection

  1. Atomic Scale Structure-Chemistry Relationships at Oxide Catalyst Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    McBriarty, Martin E.

    Oxide catalysts are integral to chemical production, fuel refining, and the removal of environmental pollutants. However, the atomic-scale phenomena which lead to the useful reactive properties of catalyst materials are not sufficiently understood. In this work, the tools of surface and interface science and electronic structure theory are applied to investigate the structure and chemical properties of catalytically active particles and ultrathin films supported on oxide single crystals. These studies focus on structure-property relationships in vanadium oxide, tungsten oxide, and mixed V-W oxides on the surfaces of alpha-Al2O3 and alpha-Fe2O 3 (0001)-oriented single crystal substrates, two materials with nearly identical crystal structures but drastically different chemical properties. In situ synchrotron X-ray standing wave (XSW) measurements are sensitive to changes in the atomic-scale geometry of single crystal model catalyst surfaces through chemical reaction cycles, while X-ray photoelectron spectroscopy (XPS) reveals corresponding chemical changes. Experimental results agree with theoretical calculations of surface structures, allowing for detailed electronic structure investigations and predictions of surface chemical phenomena. The surface configurations and oxidation states of V and W are found to depend on the coverage of each, and reversible structural shifts accompany chemical state changes through reduction-oxidation cycles. Substrate-dependent effects suggest how the choice of oxide support material may affect catalytic behavior. Additionally, the structure and chemistry of W deposited on alpha-Fe 2O3 nanopowders is studied using X-ray absorption fine structure (XAFS) measurements in an attempt to bridge single crystal surface studies with real catalysts. These investigations of catalytically active material surfaces can inform the rational design of new catalysts for more efficient and sustainable chemistry.

  2. Regional-scale relationships between aerosol and summer monsoon circulation, and precipitation over northeast Asia

    NASA Astrophysics Data System (ADS)

    Yoon, Soon-Chang; Kim, Sang-Woo; Choi, Suk-Jin; Choi, In-Jin

    2010-08-01

    We investigated the regional-scale relationships between columnar aerosol loads and summer monsoon circulation, and also the precipitation over northeast Asia using aerosol optical depth (AOD) data obtained from the 8-year MODIS, AERONET Sun/sky radiometer, and precipitation data acquired under the Global Precipitation Climatology Project (GPCP). These high-quality data revealed the regional-scale link between AOD and summer monsoon circulation, precipitation in July over northeast Asian countries, and their distinct spatial and annual variabilities. Compared to the mean AOD for the entire period of 2001-2008, the increase of almost 40-50% in the AOD value in July 2005 and July 2007 was found over the downwind regions of China (Yellow Sea, Korean peninsula, and East Sea), with negative precipitation anomalies. This can be attributable to the strong westerly confluent flows, between cyclone flows by continental thermal low centered over the northern China and anticyclonic flows by the western North Pacific High, which transport anthropogenic pollution aerosols emitted from east China to aforementioned downwind high AOD regions along the rim of the Pacific marine airmass. In July 2002, however, the easterly flows transported anthropogenic aerosols from east China to the southwestern part of China in July 2002. As a result, the AOD off the coast of China was dramatically reduced in spite of decreasing rainfall. From the calculation of the cross-correlation coefficient between MODIS-derived AOD anomalies and GPCP precipitation anomalies in July over the period 2001-2008, we found negative correlations over the areas encompassed by 105-115°E and 30-35°N and by 120-140°E and 35-40°N (Yellow Sea, Korean peninsula, and East Sea). This suggests that aerosol loads over these regions are easily influenced by the Asian monsoon flow system and associated precipitation.

  3. Convergence of macroscopic tongue anatomy in ruminants and scaling relationships with body mass or tongue length.

    PubMed

    Meier, Andrea R; Schmuck, Ute; Meloro, Carlo; Clauss, Marcus; Hofmann, Reinhold R

    2016-03-01

    Various morphological measures demonstrate convergent evolution in ruminants with their natural diet, in particular with respect to the browser/grazer dichotomy. Here, we report quantitative macroanatomical measures of the tongue (length and width of specific parts) of 65 ruminant species and relate them to either body mass (BM) or total tongue length, and to the percentage of grass in the natural diet (%grass). Models without and with accounting for the phylogenetic structures of the dataset were used, and models were ranked using Akaike's Information Criterion. Scaling relationships followed geometric principles, that is, length measures scaled with BM to the power of 0.33. Models that used tongue length rather than BM as a body size proxy were consistently ranked better, indicating that using size proxies that are less susceptible to a wider variety of factors (such as BM that fluctuates with body condition) should be attempted whenever possible. The proportion of the freely mobile tongue tip of the total tongue (and hence also the corpus length) was negatively correlated to %grass, in accordance with concepts that the feeding mechanism of browsers requires more mobile tongues. It should be noted that some nonbrowsers, such as cattle, use a peculiar mechanism for grazing that also requires long, mobile tongues, but they appear to be exceptions. A larger corpus width with increasing %grass corresponds to differences in snout shape with broader snouts in grazers. The Torus linguae is longer with increasing %grass, a finding that still warrants functional interpretation. This study shows that tongue measures covary with diet in ruminants. In contrast, the shape of the tongue (straight or "hourglass-shaped" as measured by the ratio of the widest and smallest corpus width) is unrelated to diet and is influenced strongly by phylogeny. PMID:26647882

  4. Scaling relationship for NO2 pollution and urban population size: a satellite perspective.

    PubMed

    Lamsal, L N; Martin, R V; Parrish, D D; Krotkov, N A

    2013-07-16

    Concern is growing about the effects of urbanization on air pollution and health. Nitrogen dioxide (NO2) released primarily from combustion processes, such as traffic, is a short-lived atmospheric pollutant that serves as an air-quality indicator and is itself a health concern. We derive a global distribution of ground-level NO2 concentrations from tropospheric NO2 columns retrieved from the Ozone Monitoring Instrument (OMI). Local scaling factors from a three-dimensional chemistry-transport model (GEOS-Chem) are used to relate the OMI NO2 columns to ground-level concentrations. The OMI-derived surface NO2 data are significantly correlated (r = 0.69) with in situ surface measurements. We examine how the OMI-derived ground-level NO2 concentrations, OMI NO2 columns, and bottom-up NOx emission inventories relate to urban population. Emission hot spots, such as power plants, are excluded to focus on urban relationships. The correlation of surface NO2 with population is significant for the three countries and one continent examined here: United States (r = 0.71), Europe (r = 0.67), China (r = 0.69), and India (r = 0.59). Urban NO2 pollution, like other urban properties, is a power law scaling function of the population size: NO2 concentration increases proportional to population raised to an exponent. The value of the exponent varies by region from 0.36 for India to 0.66 for China, reflecting regional differences in industrial development and per capita emissions. It has been generally established that energy efficiency increases and, therefore, per capita NOx emissions decrease with urban population; here, we show how outdoor ambient NO2 concentrations depend upon urban population in different global regions. PMID:23763377

  5. Relationships of land use mix with walking for transport: do land uses and geographical scale matter?

    PubMed

    Duncan, Mitch J; Winkler, Elisabeth; Sugiyama, Takemi; Cerin, Ester; duToit, Lorinne; Leslie, Eva; Owen, Neville

    2010-09-01

    Physical activity and public health recommendations now emphasize the creation of activity-friendly neighborhoods. Mixed land use in a neighborhood is important in this regard, as it reflects the availability of destinations to which residents can walk or ride bicycles, and thus is likely to contribute to residents' active lifestyles that in turn will influence their overall health. Relationships between land use mix (LUM) and physical activity have not been apparent in some studies, which may be because geographical scale and the specificity of hypothesized environment-behavior associations are not taken into account. We compared the strength of association of four Geographic Information Systems-derived LUM measures with walking for transport and perceived proximity to destinations. We assessed physical activity behaviors of 2,506 adults in 154 Census Collection Districts (CCDs) in Adelaide, Australia, for which ''original'' LUM measures were calculated, and then refined by either: accounting for the geographic scale of measurement; including only the most-relevant land uses; or, both. The refined (but not the ''original'') LUM measures had significant associations with the frequency of walking for transport (p < 0.05) and area-corrected measures had significant associations with the duration of walking for transport. All LUM measures had significant associations with perceived proximity to destinations, but stronger associations were seen when using the refined measures compared with the original LUM. Identifying the LUM attributes most strongly associated with walking for transport is a priority and can inform environmental and policy initiatives that are needed to promote health-enhancing physical activity. PMID:20814757

  6. Cross-scale Interactions and Changing Pattern-Process Relationships: Consequences for System Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cross-scale interactions occur either when fine-scale processes influence a broad spatial extent or a long time period, or when broad-scale drivers interact with fine-scale processes to determine system dynamics. Cross-scale interactions are increasing recognized as having important influences on e...

  7. Allometric growth in juvenile marine turtles: possible role as an antipredator adaptation.

    PubMed

    Salmon, Michael; Scholl, Joshua

    2014-04-01

    Female marine turtles produce hundreds of offspring during their lifetime but few survive because small turtles have limited defenses and are vulnerable to many predators. Little is known about how small turtles improve their survival probabilities with growth though it is assumed that they do. We reared green turtles (Chelonia mydas) and loggerheads (Caretta caretta) from hatchlings to 13 weeks of age and documented that they grew wider faster than they grew longer. This pattern of allometric growth might enable small turtles to more quickly achieve protection from gape-limited predators, such as the dolphinfish (Coryphaena hippurus). As a test of that hypothesis, we measured how dolphinfish gape increased with length, reviewed the literature to determine how dolphinfish populations were size/age structured in nearby waters, and then determined the probability that a small turtle would encounter a fish large enough to consume it if it grew by allometry vs. by isometry (in which case it retained its hatchling proportions). Allometric growth more quickly reduced the probability of a lethal encounter than did isometric growth. On that basis, we suggest that allometry during early ontogeny may have evolved because it provides a survival benefit for small turtles. PMID:24629459

  8. A Systematic Review of the Psychometric Properties of the Sexual Relationship Power Scale in HIV/AIDS Research

    PubMed Central

    McMahon, James M.; Volpe, Ellen M.; Klostermann, Keith; Trabold, Nicole; Xue, Ying

    2014-01-01

    The Sexual Relationship Power Scale (SRPS) was developed over a decade ago to address the lack of reliable and valid measures of relationship power in social, behavioral and medical research. The SRPS and its two subscales (relationship control [RC], decision-making dominance [DMD]) have been used extensively in the field of HIV prevention and sexual risk behavior. We performed a systematic review of the psychometric properties of the SRPS and subscales as reported in the HIV/AIDS literature from 2000 to 2012. A total of 54 published articles were identified that reported reliability or construct validity estimates of the scales. Description of the psychometric properties of the SRPS and subscales are reported according to study population, and several cross-population trends were identified. In general, the SRPS and RC subscale exhibited sound psychometric properties across multiple study populations and research settings. By contrast, the DMD subscale had relatively weak psychometric properties, especially when used with specific populations and research settings. Factors that influenced the psychometric properties of the various scales and subscales included the study population, mean age of the sample, number of items retained in the scale, and modifications to the original scales. We conclude with recommendations for (a) the application and use of the SRPS and subscales, (b) reporting of psychometric properties of the scales in the literature, and (c) areas for future research. PMID:25331613

  9. Relationship between Dehalococcoides DNA in ground water and rates of reductive dechlorination at field scale.

    PubMed

    Lu, Xiaoxia; Wilson, John T; Kampbell, Donald H

    2006-09-01

    Certain strains of Dehalococcoides bacteria can dechlorinate chlorinated ethylenes to harmless products. This study was conducted to determine if there is a valid association between the density of Dehalococcoides DNA in ground water and the observed rates of reductive dechlorination at field scale. Dehalococcoides DNA in water from monitoring wells was determined using the quantitative real time polymerase chain reaction (q-PCR) with DNA primer set specific for Dehalococcoides organisms. Dechlorination rate constants were extracted from field data using the BIOCHLOR software. Of the six conventional plumes surveyed, "generally useful" rates of dechlorination (greater than or equal to 0.3 per year) of cis-dichloroethylene (cis-DCE) and vinyl chloride (VC) along the flow path were observed at three sites where Dehalococcoides DNA was detected, and little attenuation of cis-DCE and VC occurred at two sites where Dehalococcoides DNA was not detected. At the two sites where there was no net direction of ground water flow, the relationship between the density of Dehalococcoides DNA in ground water and the trend in concentrations of chlorinated ethylenes over time in monitoring wells was not so consistent as that observed for the conventional plumes. A comparison of our study to a field study performed by Lendvay and his coworker indicated that monitoring wells did not efficiently sample the Dehalococcoides organisms in the aquifer. PMID:16889813

  10. Symbiotic relationship analysis of predominant bacteria in a lab-scale anammox UASB bioreactor.

    PubMed

    Wang, Yujia; Hu, Xiaomin; Jiang, Binhui; Song, Zhenhui; Ma, Yongguang

    2016-04-01

    In order to provide the comprehensive insight into the key microbial groups in anaerobic ammonium oxidation (anammox) process, high-throughput sequencing analysis has been used for the investigation of the bacterial communities of a lab-scale upflow anaerobic sludge bed (UASB) anammox bioreactor. Results revealed that 109 operational taxonomic units (OTUs; out of 14,820 reads) were identified and a domination of anammox bacteria of Candidatus Kuenenia stuttgartiensis (OTU474, 35.42 %), along with heterotrophs of Limnobacter sp. MED105 (OTU951, 14.98 %), Anerolinea thermophila UNI-1 (OTU465 and OTU833, 6.60 and 3.93 %), Azoarcus sp. B72 (OTU26, 9.47 %), and Ignavibacterium sp. JCM 16511 (OTU459, 8.33 %) were detected. Metabolic pathway analysis showed that Candidatus K. stuttgartiensis encountered gene defect in synthesizing a series of metabolic cofactors for growth, implying that K. stuttgartiensis is auxotrophic. Coincidentally, the other dominant species severally showed complete metabolic pathways with full set gene encoding to corresponding cofactors presented in the surrounding environment. Furthermore, it was likely that the survival of heterotrophs in the autotrophic system indicates the existence of a symbiotic and mutual relationship in anammox system. PMID:26739990

  11. Habitat–performance relationships: finding the right metric at a given spatial scale

    PubMed Central

    Gaillard, Jean-Michel; Hebblewhite, Mark; Loison, Anne; Fuller, Mark; Powell, Roger; Basille, Mathieu; Van Moorter, Bram

    2010-01-01

    The field of habitat ecology has been muddled by imprecise terminology regarding what constitutes habitat, and how importance is measured through use, selection, avoidance and other bio-statistical terminology. Added to the confusion is the idea that habitat is scale-specific. Despite these conceptual difficulties, ecologists have made advances in understanding ‘how habitats are important to animals’, and data from animal-borne global positioning system (GPS) units have the potential to help this clarification. Here, we propose a new conceptual framework to connect habitats with measures of animal performance itself—towards assessing habitat–performance relationship (HPR). Long-term studies will be needed to estimate consequences of habitat selection for animal performance. GPS data from wildlife can provide new approaches for studying useful correlates of performance that we review. Recent examples include merging traditional resource selection studies with information about resources used at different critical life-history events (e.g. nesting, calving, migration), uncovering habitats that facilitate movement or foraging and, ultimately, comparing resources used through different life-history strategies with those resulting in death. By integrating data from GPS receivers with other animal-borne technologies and combining those data with additional life-history information, we believe understanding the drivers of HPRs will inform animal ecology and improve conservation. PMID:20566502

  12. Relationship of core-scale heterogeneity with non-Darcy flow coefficients

    SciTech Connect

    Al-Rumhy, M.H.; Kalam, M.Z.

    1996-06-01

    An experimental research program to investigate the effects of liquid saturations upon non-Darcy flow coefficients is presented. the presence of a wetting phase fluid plays an important role in high velocity flow of a gas well, producing condensate or water, and in propped fractures containing liquid saturations. This study initially examines the errors commonly encountered but ignored in evaluating the permeabilities and the coefficient of inertial resistance during the flow of gases through porous media. Experimental techniques, such as constant overburden pressure, changing overburden pressure, forward flow, and backpressure flow, are applied to optimize and obtain accurate evaluations of Klinkenberg parameters and inertial resistance coefficients for a selection of Omani reservoir cores. Gas-slippage factor significantly influences the derived viscous and inertial coefficients from high-velocity gas flow data. An increasing wetting phase saturation increases the non-Darcy coefficient up to thirty-fold. Analysis of the experimental data revealed that unique relationships exist between the non-Darcy flow coefficients and the equivalent liquid permeability, porosity, and liquid saturation. Heterogeneity of the core as mapped by pore-scale measurements provide an insight into the mechanism for such a large increase in the non-Darcy coefficients.

  13. Intraspecific scaling of arterial blood pressure in the Burmese python.

    PubMed

    Enok, Sanne; Slay, Christopher; Abe, Augusto S; Hicks, James W; Wang, Tobias

    2014-07-01

    Interspecific allometric analyses indicate that mean arterial blood pressure (MAP) increases with body mass of snakes and mammals. In snakes, MAP increases in proportion to the increased distance between the heart and the head, when the heart-head vertical distance is expressed as ρgh (where ρ is the density of blood, G: is acceleration due to gravity and h is the vertical distance above the heart), and the rise in MAP is associated with a larger heart to normalize wall stress in the ventricular wall. Based on measurements of MAP in Burmese pythons ranging from 0.9 to 3.7 m in length (0.20-27 kg), we demonstrate that although MAP increases with body mass, the rise in MAP is merely half of that predicted by heart-head distance. Scaling relationships within individual species, therefore, may not be accurately predicted by existing interspecific analyses. PMID:24737752

  14. Structure-Property Relationships in Atomic-Scale Junctions: Histograms and Beyond.

    PubMed

    Hybertsen, Mark S; Venkataraman, Latha

    2016-03-15

    are pulled apart has given complementary information such as the stiffness and rupture force of the molecule-metal link bond. Overall, while the BJ technique does not produce a single molecule circuit for practical applications, it has proved remarkably versatile for fundamental studies. Measured data and analysis have been combined with atomic-scale theory and calculations, typically performed for representative junction structures, to provide fundamental physical understanding of structure-function relationships. This Account integrates across an extensive series of our specific nanoscale junction studies which were carried out with the STM- and AFM-BJ techniques and supported by theoretical analysis and density functional theory based calculations, with emphasis on the physical characteristics of the measurement process and the rich data sets that emerge. Several examples illustrate the impact of measured trends based on the most probable values for key characteristics (obtained from ensembles of order 1000-10 000 individual junctions) to build a solid picture of conductance phenomena as well as attributes of the link bond chemistry. The key forward-looking question posed here is the extent to which the full data sets represented by the individual trajectories can be analyzed to address structure-function questions at the level of individual junctions. Initial progress toward physical modeling of conductance of individual junctions indicates trends consistent with physical junction structures. Analysis of junction mechanics reveals a scaling procedure that collapses existing data onto a universal force-extension curve. This research directed to understanding the distribution of structures and physical characteristics addresses fundamental questions concerning the interplay between chemical control and stochastically driven diversity. PMID:26938931

  15. Relationships between biodiversity and the stability of marine ecosystems: Comparisons at a European scale using meta-analysis

    NASA Astrophysics Data System (ADS)

    Cusson, Mathieu; Crowe, Tasman P.; Araújo, Rita; Arenas, Francisco; Aspden, Rebbecca; Bulleri, Fabio; Davoult, Dominique; Dyson, Kirstie; Fraschetti, Simonetta; Herkül, Kristjan; Hubas, Cédric; Jenkins, Stuart; Kotta, Jonne; Kraufvelin, Patrik; Migné, Aline; Molis, Markus; Mulholland, Olwyen; Noël, Laure M.-L. J.; Paterson, David M.; Saunders, James; Somerfield, Paul J.; Sousa-Pinto, Isabel; Spilmont, Nicolas; Terlizzi, Antonio; Benedetti-Cecchi, Lisandro

    2015-04-01

    The relationship between biodiversity and stability of marine benthic assemblages was investigated through meta-analyses using existing data sets (n = 28) covering various spatial (m-km) and temporal (1973-2006; ranging from 5 to > 250 months) scales in different benthic habitats (emergent rock, rock pools and sedimentary habitats) over different European marine systems (North Atlantic and western Mediterranean). Stability was measured by a lower variability in time, and variability was estimated as temporal variance of species richness, total abundance (density or % cover) and community structure (using Bray-Curtis dissimilarities on species composition and abundance). Stability generally decreased with species richness. Temporal variability in species richness increased with the number of species at both quadrat (< 1 m2) and site (~ 100 m2) scales, while no relationship was observed by multivariate analyses. Positive relationships were also observed at the scale of site between temporal variability in species richness and variability in community structure with evenness estimates. This implies that the relationship between species richness or evenness and species richness variability is slightly positive and depends on the scale of observation. Thus, species richness does not stabilize temporal fluctuations in species number, rather species rich assemblages are those most likely to undergo the largest fluctuations in species numbers and abundance from time to time. Changes within community assemblages in terms of structure are, however, generally independent of biodiversity. Except for sedimentary and rock pool habitats, no relationship was observed between temporal variation of total abundances and diversity at either scale. Overall, our results emphasize that the relation between species richness and species-level measures of temporal variability depends on scale of measurements, type of habitats and the marine system (North Atlantic and Mediterranean

  16. Larval serum proteins of the gypsy moth, Lymantria dispar: Allometric changes during development suggest several functions for arylphorin and lipophorin

    SciTech Connect

    Karpells, S.T.

    1989-01-01

    Storage proteins are the major nutritive intermediates in insects and although the serum storage proteins are relatively well studied, definitive roles for many of them have yet to be established. To further characterize their roles in development and to establish quantitative baselines for future studies, two serum proteins, arylphorin (Ap) and lipophorin (Lp), of the gypsy moth, Lymantria dispar, were studied. Ap and Lp, isolated from larval hemolymph, were partially characterized biochemically and immunologically. Hemolymph concentrations throughout larval development were determined using quantitative immunoelectrophoresis and absolute hemolymph amounts of protein were determined by measuring hemolymph volume. Cyclic fluctuations in hemolymph concentrations of Ap in particular correlated with each molting cycle and an increase in Lp levels just prior to pupation suggest a metamorphic change in the role or demand for the protein. Sexual dimorphism in protein concentrations are explained in part by the sexual dimorphism in the number of larval instars. In fact, an additional instar of Ap accumulation in the female gypsy moth is suggested to compensate for the lack of a female-specific storage protein in this species. The last two days of each instar were found to be the optimum time to sample protein concentration with minimum variance. Allometric relationships among Ap accumulation, Lp accumulation and weight gain were uncovered. Ap labelled with ({sup 14}C)-N-ethylmaleimide was shown to be incorporated into newly synthesized cuticle and setae during a larval-larval molt. The antiserum developed against L. dispar Ap was used to identify the Ap of Trichoplusia in and study Ap titers in parasitized T. in larvae. The antiserum was also used to determine the immunological relatedness of 5 species of Lepidoptera.

  17. Interactions between large-scale modes of climate and their relationship with Australian climate and hydrology

    NASA Astrophysics Data System (ADS)

    Whan, K. R.; Lindesay, J. A.; Timbal, B.; Raupach, M. R.; Williams, E.

    2010-12-01

    Australia’s natural environment is adapted to low rainfall availability and high variability but human systems are less able to adapt to variability in the hydrological cycle. Understanding the mechanisms underlying drought persistence and severity is vital to contextualising future climate change. Multiple external forcings mean the mechanisms of drought occurrence in south-eastern Australian are complex. The key influences on SEA climate are El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), the Southern Annular Mode (SAM) and the sub-tropical ridge (STR); each of these large-scale climate modes (LSCM) has been studied widely. The need for research into the interactions among the modes has been noted [1], although to date this has received limited attention. Relationships between LSCM and hydrometeorological variability are nonlinear, making linearity assumptions underlying usual statistical techniques (e.g. correlation, principle components analysis) questionable. In the current research a statistical technique that can deal with nonlinear interactions is applied to a new dataset enabling a full examination of the Australian water balance. The Australian Water Availability Project (AWAP) dataset models the Australian water balance on a fine grid [2]. Hydrological parameters (e.g. soil moisture, evaporation, runoff) are modelled from meteorological data, allowing the complete Australian water balance (climate and hydrology) to be examined and the mechanisms of drought to be studied holistically. Classification and regression trees (CART) are a powerful regression-based technique that is capable of accounting for nonlinear effects. Although it has limited previous application in climate research [3] this methodology is particularly informative in cases with multiple predictors and nonlinear relationships such as climate variability. Statistical relationships between variables are the basis for the decision rules in CART that are used to split

  18. An Examination of Coach and Player Relationships According to the Adapted LMX 7 Scale: A Validity and Reliability Study

    ERIC Educational Resources Information Center

    Caliskan, Gokhan

    2015-01-01

    The current study aims to test the reliability and validity of the Leader-Member Exchange (LMX 7) scale with regard to coach--player relationships in sports settings. A total of 330 professional soccer players from the Turkish Super League as well as from the First and Second Leagues participated in this study. Factor analyses were performed to…

  19. Factor Structure of the Student-Teacher Relationship Scale for Norwegian School-Age Children Explored with Confirmatory Factor Analysis

    ERIC Educational Resources Information Center

    Drugli, May Britt; Hjemdal, Odin

    2013-01-01

    The validity of the Student-Teacher Relationship Scale (STRS) was examined in a national sample of 863 Norwegian schoolchildren in grades 1-7 (aged 6-13). The original factor structure of the STRS was tested by confirmatory factor analysis (CFA). The CFA results did not support the original three-factor structure of the STRS. Subsequent CFA of the…

  20. Brief Report: Intimacy, Passion, and Commitment in Romantic Relationships--Validation of a "Triangular Love Scale" for Adolescents

    ERIC Educational Resources Information Center

    Overbeek, Geertjan; Ha, Thao; Scholte, Ron; de Kemp, Raymond; Engels, Rutger C. M. E.

    2007-01-01

    This study examined the psychometric properties of an adolescent version of the "triangular love scale" (TLS), which assesses three components of romantic relationships: intimacy, passion, and commitment. Using data from 435 Dutch adolescents aged 12-18 years, we found evidence for convergent validity, showing that dimensions of intimacy, passion,…

  1. Developing the Internet-Savviness (IS) Scale: Investigating the Relationships between Internet Use and Academically Talented Middle School Youth

    ERIC Educational Resources Information Center

    Geyer, Roger W.

    2009-01-01

    This study investigated the development and validation of a 32-item scale that measures "Internet-Savviness" (IS). Relationships between this multidimensional construct and other primary variables of interest including age, gender, Internet access, Internet location, and Internet activities were explored. The sample population consisted of 241…

  2. The Relationship between Student Achievement, School District Economies of Scale, School District Size, and Student Socioeconomic Status

    ERIC Educational Resources Information Center

    Trani, Randy

    2009-01-01

    The relationships between student achievement, school district economies of scale, school district size and student socioeconomic status were measured for 131 school districts in the state of Oregon. Data for school districts ranging in size from districts with around 300 students to districts with more than 40,000 students were collected for…

  3. The Consequences of Perfectionism Scale: Factorial Structure and Relationships with Perfectionism, Performance Perfectionism, Affect, and Depressive Symptoms

    ERIC Educational Resources Information Center

    Stoeber, Joachim; Hoyle, Azina; Last, Freyja

    2013-01-01

    This study investigated the Consequences of Perfectionism Scale (COPS) and its relationships with perfectionism, performance perfectionism, affect, and depressive symptoms in 202 university students using confirmatory factor analysis, correlations, and regression analyses. Results suggest that the COPS is a reliable and valid measure of positive…

  4. Relationship between Perceived and Actual Frequency Represented by Common Rating Scale Labels

    ERIC Educational Resources Information Center

    Woltz, Dan J.; Gardner, Michael K.; Kircher, John C.; Burrow-Sanchez, Jason J.

    2012-01-01

    Two experiments investigated the relationship between subjective interpretation of frequency terms and corresponding objective values. Evidence supported the existence of a nonlinear relationship that is well described by a logarithmic function. The general form of this relationship was consistent across different methods of eliciting subjective…

  5. Examining The Student-Teacher Relationship Scale in the Italian Context: A Factorial Validity Study

    ERIC Educational Resources Information Center

    Fraire, Michela; Longobardi, Claudio; Prino, Laura Elvira; Sclavo, Erica; Settanni, Michele

    2013-01-01

    Introduction: A growing body of literature suggest that the quality of teacher-child relationships is a determining factor in children's competence in social-emotional, behavioral functioning, and academic skills. Most of the research on student-teacher relationships has relied on these relationship perceptions. A well-known instrument to…

  6. Earthquake source parameters and scaling relationships from microseismicity at TauTona Gold Mine, South Africa

    NASA Astrophysics Data System (ADS)

    Moyer, P. A.; Boettcher, M. S.

    2012-12-01

    The issue of earthquake source scaling continues to draw considerable debate within the seismological community. Findings that both support and refute the claim that systematic differences between the source processes of small and large earthquakes may exist, motivate the study of how source parameters, such as seismic moment, corner frequency, radiated seismic energy, and apparent stress, scale over a wide range of magnitudes. To address this question, we are conducting a compressive examination of earthquake source parameters from microseismicity recorded at the TauTona gold mine in South Africa. At the TauTona gold mine, hundreds to thousands of earthquakes are recorded everyday within a few meters to kilometers of seismometers installed at depth throughout the mine. This high-rate of seismicity and close proximity to the recording instruments provides the ideal location and dataset to investigate source parameters and scaling relationships for earthquakes with a wide magnitude range of -4 < Mw < 4. We focus our investigation on earthquakes recorded during mining quiet hours to minimize blasts and rockburts in our catalog, and focus on earthquakes that occurred along the Pretorious Fault, the largest fault system running through the mine, to evaluate source parameters of fault zone earthquakes. The mine seismic network operated by the Institute of Mine Seismology (IMS) with a sample rate range of 3 - 2000 Hz has been enhanced by a tight array of high-quality instruments deployed in the Pretorious Fault Zone at the deepest part of the mine (~3.6 km depth) as part of the Natural Laboratory in South African Mines (NELSAM). The NELSAM network includes 3 strong-motion accelerometers, 5 weak-motion accelerometers, and 3 geophones with a combined sample rate range of 6 - 12 kHz that allows us to reliably constrain corner frequencies of very small earthquakes. We use spectral analysis techniques and an omega-squared source model determined by an Empirical Green

  7. Unraveling Kinase Activation Dynamics Using Kinase-Substrate Relationships from Temporal Large-Scale Phosphoproteomics Studies

    PubMed Central

    Chaudhuri, Rima; Yang, Pengyi; Vafaee, Fatemeh; Fazakerley, Daniel; Humphrey, Sean; James, David; Kuncic, Zdenka

    2016-01-01

    In response to stimuli, biological processes are tightly controlled by dynamic cellular signaling mechanisms. Reversible protein phosphorylation occurs on rapid time-scales (milliseconds to seconds), making it an ideal carrier of these signals. Advances in mass spectrometry-based proteomics have led to the identification of many tens of thousands of phosphorylation sites, yet for the majority of these the kinase is unknown and the underlying network topology of signaling networks therefore remains obscured. Identifying kinase substrate relationships (KSRs) is therefore an important goal in cell signaling research. Existing consensus sequence motif based prediction algorithms do not consider the biological context of KSRs, and are therefore insensitive to many other mechanisms guiding kinase-substrate recognition in cellular contexts. Here, we use temporal information to identify biologically relevant KSRs from Large-scale In Vivo Experiments (KSR-LIVE) in a data-dependent and automated fashion. First, we used available phosphorylation databases to construct a repository of existing experimentally-predicted KSRs. For each kinase in this database, we used time-resolved phosphoproteomics data to examine how its substrates changed in phosphorylation over time. Although substrates for a particular kinase clustered together, they often exhibited a different temporal pattern to the phosphorylation of the kinase. Therefore, although phosphorylation regulates kinase activity, our findings imply that substrate phosphorylation likely serve as a better proxy for kinase activity than kinase phosphorylation. KSR-LIVE can thereby infer which kinases are regulated within a biological context. Moreover, KSR-LIVE can also be used to automatically generate positive training sets for the subsequent prediction of novel KSRs using machine learning approaches. We demonstrate that this approach can distinguish between Akt and Rps6kb1, two kinases that share the same linear consensus motif

  8. Unraveling Kinase Activation Dynamics Using Kinase-Substrate Relationships from Temporal Large-Scale Phosphoproteomics Studies.

    PubMed

    Domanova, Westa; Krycer, James; Chaudhuri, Rima; Yang, Pengyi; Vafaee, Fatemeh; Fazakerley, Daniel; Humphrey, Sean; James, David; Kuncic, Zdenka

    2016-01-01

    In response to stimuli, biological processes are tightly controlled by dynamic cellular signaling mechanisms. Reversible protein phosphorylation occurs on rapid time-scales (milliseconds to seconds), making it an ideal carrier of these signals. Advances in mass spectrometry-based proteomics have led to the identification of many tens of thousands of phosphorylation sites, yet for the majority of these the kinase is unknown and the underlying network topology of signaling networks therefore remains obscured. Identifying kinase substrate relationships (KSRs) is therefore an important goal in cell signaling research. Existing consensus sequence motif based prediction algorithms do not consider the biological context of KSRs, and are therefore insensitive to many other mechanisms guiding kinase-substrate recognition in cellular contexts. Here, we use temporal information to identify biologically relevant KSRs from Large-scale In Vivo Experiments (KSR-LIVE) in a data-dependent and automated fashion. First, we used available phosphorylation databases to construct a repository of existing experimentally-predicted KSRs. For each kinase in this database, we used time-resolved phosphoproteomics data to examine how its substrates changed in phosphorylation over time. Although substrates for a particular kinase clustered together, they often exhibited a different temporal pattern to the phosphorylation of the kinase. Therefore, although phosphorylation regulates kinase activity, our findings imply that substrate phosphorylation likely serve as a better proxy for kinase activity than kinase phosphorylation. KSR-LIVE can thereby infer which kinases are regulated within a biological context. Moreover, KSR-LIVE can also be used to automatically generate positive training sets for the subsequent prediction of novel KSRs using machine learning approaches. We demonstrate that this approach can distinguish between Akt and Rps6kb1, two kinases that share the same linear consensus motif

  9. Relationship between the large-scale air circulation and frequency of very warm days in Romania

    NASA Astrophysics Data System (ADS)

    Stefan, Sabina; Barbu, Nicu; Baciu, Madalina

    2015-04-01

    In this work is investigated the relationship between the large-scale air circulation and frequency of very warm days (frequency of days with maximum temperature greater or equal to 90th percentile - FrTmax90). This analysis is conducted for summer and winter over the period 1962-2010. Daily temperature data recorded at 85 Romanian meteorological stations with complete observations over the study period were used to calculate the FrTmax90 for summer and winter. Daily air circulation types computed by using two objective catalogues, namely GWT (GrossWetter-Typen) and WLK (WetterLargenKlassifikation) from COST733Action were used to calculate the air circulation frequency for summer and winter. NCEP/NCAR gridded reanalysis data sets were used. For the GWT catalogue the sea level pressure data sets were used to classify the air circulation in the 18 types. In the case of the WLK catalogue the geopotential height at 925 and 500 hPa, zonal and meridional components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column were used to classify the air circulation in the 40 types. For winter were obtained 4 clusters and for summer 8 clusters of FrTmax90 by using a clusterization method. These clusters present homogeneity related to the FrTmax90. The Pearson correlation coefficient (R) is calculated between the FrTmax90 and the air circulation types. The results show that correlation coefficients are greatest in winter than in summer for the GWT catalogue compared to the WLK catalogue. The greatest correlation coefficients was obtained during winter for southwestern-anticyclones (SW[A]) circulation type for all the 4 clusters according to the GWT catalogue. The northwestern-anticyclones-wet (NW-AAW) circulation type presents the greatest correlation coefficient only for the cluster 3 according to the WLK catalogue. We can note that these results depend on the both large-scale air circulation and orography (the Carpathians).

  10. Relationship Between Large-Scale Functional and Structural Covariance Networks in Idiopathic Generalized Epilepsy

    PubMed Central

    Zhang, Zhiqiang; Mantini, Dante; Xu, Qiang; Wang, Zhengge; Chen, Guanghui; Jiao, Qing; Zang, Yu-Feng

    2013-01-01

    Abstract The human brain can be modeled as a network, whose structure can be revealed by either anatomical or functional connectivity analyses. Little is known, so far, about the topological features of the large-scale interregional functional covariance network (FCN) in the brain. Further, the relationship between the FCN and the structural covariance network (SCN) has not been characterized yet, in the intact as well as in the diseased brain. Here, we studied 59 patients with idiopathic generalized epilepsy characterized by tonic–clonic seizures and 59 healthy controls. We estimated the FCN and the SCN by measuring amplitude of low-frequency fluctuations (ALFF) and gray matter volume (GMV), respectively, and then we conducted graph theoretical analyses. Our ALFF-based FCN and GMV-based results revealed that the normal human brain is characterized by specific topological properties such as small worldness and highly-connected hub regions. The patients had an altered overall topology compared to the controls, suggesting that epilepsy is primarily a disorder of the cerebral network organization. Further, the patients had altered nodal characteristics in the subcortical and medial temporal regions and default-mode regions, for both the FCN and SCN. Importantly, the correspondence between the FCN and SCN was significantly larger in patients than in the controls. These results support the hypothesis that the SCN reflects shared long-term trophic mechanisms within functionally synchronous systems. They can also provide crucial information for understanding the interactions between the whole-brain network organization and pathology in generalized tonic–clonic seizures. PMID:23510272

  11. Earthquake source parameters and scaling relationships in Hungary (central Pannonian basin)

    NASA Astrophysics Data System (ADS)

    Süle, Bálint; Wéber, Zoltán

    2013-04-01

    Fifty earthquakes that occurred in Hungary (central part of the Pannonian basin) with local magnitude M_{L} ranging from 0.8 to 4.5 have been analyzed. The digital seismograms used in this study were recorded by six permanent broadband stations and 20 short-period ones at hypocentral distances between 10 and 327 km. The displacement spectra for P- and SH-waves were analyzed according to Brune's source model. Observed spectra were corrected for path-dependent attenuation effects using an independent regional estimate of the quality factor Q S . To correct spectra for near-surface attenuation, the κ parameter was calculated, obtaining it from waveforms recorded at short epicentral distances. The values of the κ parameter vary between 0.01 and 0.06 s with a mean of 0.03 s for P-waves and between 0.01 and 0.09 s with a mean of 0.04 s for SH-waves. After correction for attenuation effects, spectral parameters (corner frequency and low-frequency spectral level) were estimated by a grid search algorithm. The obtained seismic moments range from 4.21×1011 to 3.41×1015 Nm (1.7 ≤ M w ≤ 4.3). The source radii are between 125 and 1,343 m. Stress drop values vary between 0.14 and 32.4 bars with a logarithmic mean of 2.59 bars (1 bar = 105 Pa). From the results, a linear relationship between local and moment magnitudes has been established. The obtained scaling relations show slight evidence of self-similarity violation. However, due to the high scatter of our data, the existence of self-similarity cannot be excluded.

  12. Injury Rehabilitation Overadherence: Preliminary Scale Validation and Relationships With Athletic Identity and Self-Presentation Concerns

    PubMed Central

    Podlog, Leslie; Gao, Zan; Kenow, Laura; Kleinert, Jens; Granquist, Megan; Newton, Maria; Hannon, James

    2013-01-01

    Context: Evidence suggests that nonadherence to rehabilitation protocols may be associated with worse clinical and functional rehabilitation outcomes. Recently, it has been recognized that nonadherence may not only reflect a lack of rehabilitation engagement but that some athletes may “overadhere” to their injury-rehabilitation regimen or risk a premature return to sport. Presently, no measure of overadherence exists, and correlates of overadherence and risking a premature return to sport remain uncertain. Objective: To provide initial validation of a novel injury-rehabilitation overadherence measure (study 1) and to examine correlates of overadherence and risking a premature return to sport (study 2). Design: Cross-sectional study. Setting: High school athletes (study 1) and collegiate athletes (study 2). Patients or Other Participants: In study 1, 118 currently injured US adolescent athletes competing in a range of high school sports participated. In study 2, 105 currently injured collegiate athletes (National Collegiate Athletic Association Divisions I–III) volunteered. Main Outcome Measure(s): The Rehabilitation Overadherence Questionnaire was a novel instrument developed to assess injured athletes' tendency toward overadherence behaviors and beliefs. We used an adapted version of the Injury Psychological Readiness to Return to Sport Scale to assess the tendency to risk a premature return to sport. Results: In study 1, the construct validity of the overadherence measure was supported using principal axis factoring. Moreover, bivariate correlation and regression analyses indicated that self-presentation concerns and athletic identity were positive predictors of adolescent rehabilitation overadherence and a premature return to sport. Study 2 provided support for the 2-factor structure of the overadherence measure found in study 1 via confirmatory factor analysis. Further support for the relationship among self-presentation concerns, athletic identity, and

  13. RELATIONSHIPS BETWEEN LABORATORY AND PILOT-SCALE COMBUSTION OF SOME CHLORINATED HYDROCARBONS

    EPA Science Inventory

    Factors governing the occurence of trace amounts of residual organic substance emmissions (ROSEs) in full-scale incierators are not fully understood. Pilot-scale spray combustion expereiments involving some liquid chlorinated hydrocarbons (CHCs) and their dilute mixtures with hy...

  14. Proportional Reasoning Ability and Concepts of Scale: Surface Area to Volume Relationships in Science

    ERIC Educational Resources Information Center

    Taylor, Amy; Jones, Gail

    2009-01-01

    The "National Science Education Standards" emphasise teaching unifying concepts and processes such as basic functions of living organisms, the living environment, and scale. Scale influences science processes and phenomena across the domains. One of the big ideas of scale is that of surface area to volume. This study explored whether or not there…

  15. Validity of the Leadership Attitudes and Beliefs Scale: Relationships with Personality, Communal Orientation, and Social Desirability.

    ERIC Educational Resources Information Center

    Wielkiewicz, Richard M.

    2002-01-01

    The Leadership Attitudes and Beliefs Scale was studied in 65 males and 111 females between 19 and 22 years old. Results supported the convergent and discriminantive validity of the Systemic Thinking scale and the divergent and discriminantive validity of the Hierarchical Thinking scale. (Contains 61 references and 2 tables.) (GCP)

  16. General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

    PubMed Central

    Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B.; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M.; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W.; Wolters, Volkmar; Schrumpf, Marion

    2012-01-01

    Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider

  17. General relationships between abiotic soil properties and soil biota across spatial scales and different land-use types.

    PubMed

    Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W; Wolters, Volkmar; Schrumpf, Marion

    2012-01-01

    Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider

  18. Scaling relationships for diffusive boundary layer thickness and diffusive flux based on in situ measurements in coastal seas

    NASA Astrophysics Data System (ADS)

    Wang, Jianing; Zhao, Liang; Fan, Renfu; Wei, Hao

    2016-05-01

    In situ measurements of the diffusive boundary layer (DBL) and bottom boundary layer (BBL) under different dynamic and oxygen environments in three coastal seas are analyzed. Previous scaling methods for the DBL thickness (δDBL) are summarized. Three methods that lead to consistent dimensions at both sides of the derived relationships have all been rooted in the Batchelor length scale. The method representing the Batchelor length scale as a function of flow speed (U) is found to be the most appropriate for scaling δDBL when the law of wall applies. Diffusive flux is controlled by the dynamic-forced δDBL and the difference in oxygen concentration over the DBL (ΔC). Values of ΔC could be scaled using the oxygen concentration of the BBL (CBBL) and the normalized benthic temperature. An effective method is developed for scaling the diffusive flux based on measurements of benthic temperature, salinity, U, CBBL, and the estimation of bottom roughness. The scaling of δDBL based mainly on U and the scaling of diffusive flux well fit data from the three sites, despite their distinct differences in dynamic and oxygen environments.

  19. A critical appraisal of allometric growth among alpine cirques based on multivariate statistics and spatial analysis

    NASA Astrophysics Data System (ADS)

    Delmas, Magali; Gunnell, Yanni; Calvet, Marc

    2015-01-01

    When considering the morphometric attributes of a glacial cirque, imbalances between length, width, and amplitude have been deemed relevant tools for discriminating between two possible pathways of cirque growth: downwearing by glaciers or backwearing by freeze-thaw processes. Based on a sample of 1071 cirques in the French Pyrenees, we reframe the concern for climatic variables by also granting systematic consideration to cirque lithology. Insight into the factors that control cirque shape is gained from Principal Component Analysis, where maps of eigenvalues assigned to six classes of bedrock display spatial patterns of cirque form as a function of position along the regional climatic gradient. Among crystalline rocks (granite, gneiss, migmatite), cirque form is predominantly determined by climatic controls. This is highlighted in the contrast between the elevated core of the Pleistocene icefield, where cirque isometry prevails, and the more peripheral areas (external sierras of the Atlantic precipitation zone and high sierras of the drier Mediterranean zone) where the lighter imprint of glaciation on the landscape has failed to erase (through glacial deepening) the allometric signature of pre-Pleistocene topographic features such as shallow valley heads and etch-basins. As a result, wide and shallow cirques occur in these settings. Among schist outcrops, in contrast, cirque form appears randomly distributed, suggesting that bedrock characteristics (e.g., structure) rather than climate are the key controls on cirque growth patterns. Given the importance of geological structure and preglacial topographic inheritance, cirques are complex landforms for which assumptions of allometric growth may be spurious. It follows that form is not always a reliable guide to process.

  20. USING THE PARENT-INFANT RELATIONSHIP GLOBAL ASSESSMENT SCALE TO IDENTIFY CAREGIVER-INFANT/TODDLER DYADS WITH ABUSIVE RELATIONSHIP PATTERNS IN SIX EUROPEAN COUNTRIES.

    PubMed

    Hatzinikolaou, Kornilia; Karveli, Vassiliki; Skoubourdi, Aggeliki; Zarokosta, Foteini; Antonucci, Gianluca; Visci, Giovanni; Calheiros, Maria Manuela; MagalhÃes, Eunice; Essau, Cecilia; Allan, Sharon; Pithia, Jayshree; Walji, Fahreen; Ezpeleta, Lourdes; Perez-Robles, Ruth; Fanti, Kostas A; Katsimicha, Evita; Hadjicharambous, Maria-Zoe; Nikolaidis, George; Reddy, Vasudevi

    2016-07-01

    The study examined whether the Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood, Revised Edition (DC: 0-3R; ZERO TO THREE, 2005) Parent-Infant Relationship Global Assessment Scale (PIR-GAS) is applicable to six European countries and contributes to the identification of caregiver-infant/toddler dyads with abusive relationship patterns. The sample consisted of 115 dyads with children's ages ranging from 1 to 47 months. Sixty-four dyads were recruited from community settings without known violence problems, and 51 dyads were recruited from clinical settings and already had been identified with violence problems or as being at risk for violence problems. To classify the dyads on the PIR-GAS categories, caregiver-child interactions were video-recorded and coded with observational scales appropriate for child age. To test whether the PIR-GAS allows for reliable identification of dyads with abusive relationship patterns, PIR-GAS ratings were compared with scores on the the International Society for the Prevention of Child Abuse and Neglect's (ISPCAN) Child Abuse Screening Tool-Parental Version (ICAST-P; D.K. Runyan et al., ), a questionnaire measuring abusive parental disciplinary practices. It was found that PIR-GAS ratings differentiated between the general and the clinical sample, and the dyads with abusive patterns of relationship were identified by both the PIR-GAS and the ICAST-P. Interrater reliability for the PIR-GAS ranged from moderate to excellent. The value of a broader use of tools such as the DC: 0-3R to promote early identification of families at risk for infant and toddler abuse and neglect is discussed. PMID:27351372

  1. Scaling up the diversity-resilience relationship with trait databases and remote sensing data: the recovery of productivity after wildfire.

    PubMed

    Spasojevic, Marko J; Bahlai, Christie A; Bradley, Bethany A; Butterfield, Bradley J; Tuanmu, Mao-Ning; Sistla, Seeta; Wiederholt, Ruscena; Suding, Katharine N

    2016-04-01

    Understanding the mechanisms underlying ecosystem resilience - why some systems have an irreversible response to disturbances while others recover - is critical for conserving biodiversity and ecosystem function in the face of global change. Despite the widespread acceptance of a positive relationship between biodiversity and resilience, empirical evidence for this relationship remains fairly limited in scope and localized in scale. Assessing resilience at the large landscape and regional scales most relevant to land management and conservation practices has been limited by the ability to measure both diversity and resilience over large spatial scales. Here, we combined tools used in large-scale studies of biodiversity (remote sensing and trait databases) with theoretical advances developed from small-scale experiments to ask whether the functional diversity within a range of woodland and forest ecosystems influences the recovery of productivity after wildfires across the four-corner region of the United States. We additionally asked how environmental variation (topography, macroclimate) across this geographic region influences such resilience, either directly or indirectly via changes in functional diversity. Using path analysis, we found that functional diversity in regeneration traits (fire tolerance, fire resistance, resprout ability) was a stronger predictor of the recovery of productivity after wildfire than the functional diversity of seed mass or species richness. Moreover, slope, elevation, and aspect either directly or indirectly influenced the recovery of productivity, likely via their effect on microclimate, while macroclimate had no direct or indirect effects. Our study provides some of the first direct empirical evidence for functional diversity increasing resilience at large spatial scales. Our approach highlights the power of combining theory based on local-scale studies with tools used in studies at large spatial scales and trait databases to

  2. The Aeolian Volcanic Arc: New Insights From Subduction Zone Thermal Models and Mineral Solubility Scaling Relationships

    NASA Astrophysics Data System (ADS)

    Creamer, J.; van Keken, P.; Engdahl, E. R.; Spera, F. J.; Bohrson, W. A.

    2007-12-01

    . 2002 and includes power-law olivine rheology and shear-heating scaled to fit forearc heat flow. The computed thermal model is used with a thermodynamically-based mineral solubility scaling relationship between fluid solute content and the relative permittivity of the fluid to infer the solute content of a slab-derived aqueous fluid existing in equilibrium with slab and mantle wedge mineralogy. The relative abundances of different solutes in slab-derived fluids are critical in determining the trace element characteristics of subduction zone magmas. Among some of the Aeolian arc volcanic centers, the recent (<30 ky) evolution in magma composition from calc-alkaline to high-potassium has been variably attributed to melting of distinct source regions, or the increasing abundance of aqueous fluids in a source region associated with a young/incipient arc. Our approach of thermal-field and solute content modeling can contribute to the resolution of this and other petrogenesis questions for Aeolian arc lavas.

  3. Remote sensing and fish-habitat relationships in coral reef ecosystems: review and pathways for multi-scale hierarchical research.

    PubMed

    Mellin, Camille; Andréfouët, Serge; Kulbicki, Michel; Dalleau, Mayeul; Vigliola, Laurent

    2009-01-01

    Understanding spatial variations in alpha, beta, and gamma coral reef fish diversity, as well as both local community and regional metacommunity structures, is critical for science and conservation of coral reef ecosystems. This quest implies that fish-habitat relationships are characterized across different spatial scales. Remote sensing allows now for a routine description of habitats from global-regional to detailed reef scales, thus theoretically offering access to hierarchical spatial analysis at multiple scales. To judge the progress in using remotely sensed habitat variables for reef fish study, existing peer-reviewed papers on the subject are reviewed. We tabulated the significant fish-habitat relationships given the different study sites, fish and habitat variables, statistical analysis, sampling efforts and scales. Studies generally do not corroborate each other. Instead, the exercise provides a diversity of thematic results from which lessons remain equivocal. It is thus justified to recommend more systematic and hierarchical remote-sensing based research in the future. We advocate the use of remote-sensing early in the design of the fish study, as part of a coherent conceptual scheme spanning all spatial scales. PMID:19058817

  4. Scaling behaviors of weighted food webs as energy transportation networks.

    PubMed

    Zhang, Jiang; Guo, Liangpeng

    2010-06-01

    Food webs can be regarded as energy transporting networks in which the weight of each edge denotes the energy flux between two species. By investigating 21 empirical weighted food webs as energy flow networks, we found several ubiquitous scaling behaviors. Two random variables A(i) and C(i) defined for each vertex i, representing the total flux (also called vertex intensity) and total indirect effect or energy store of i, were found to follow power law distributions with the exponents alpha approximately 1.32 and beta approximately 1.33, respectively. Another scaling behavior is the power law relationship, C(i) approximately A(i)(eta), where eta approximately 1.02. This is known as the allometric scaling power law relationship because A(i) can be treated as metabolism and C(i) as the body mass of the sub-network rooted from the vertex i, according to the algorithm presented in this paper. Finally, a simple relationship among these power law exponents, eta=(alpha-1)/(beta-1), was mathematically derived and tested by the empirical food webs. PMID:20303987

  5. Relationship between North American winter temperature and large-scale atmospheric circulation anomalies and its decadal variation

    NASA Astrophysics Data System (ADS)

    Yu, B.; Lin, H.; Wu, Z. W.; Merryfield, W. J.

    2016-07-01

    The interannual relationship between North American (NA) winter temperature and large-scale atmospheric circulation anomalies and its decadal variation are analyzed. NA temperature anomalies are dominated by two leading maximum covariance analysis (MCA) modes of NA surface temperature and Northern Hemisphere 500 hPa geopotential anomalies. A new teleconnection index, termed the Asian-Bering-North American (ABNA) pattern, is constructed from the normalized geopotential field after linearly removing the contribution of the Pacific-North American (PNA) pattern. The ABNA pattern is sustained by synoptic eddy forcing. The first MCA mode of NA surface temperature is highly correlated with the PNA and ABNA teleconnections, and the second mode with the North Atlantic Oscillation (NAO). This indicates that NA temperature is largely controlled by these three large-scale atmospheric patterns, i.e., the PNA, ABNA and NAO. These temperature-circulation relationships appear stationary in the 20th century.

  6. Trends in methanol decomposition on transition metal alloy clusters from scaling and Brønsted–Evans–Polanyi relationships

    SciTech Connect

    Mehmood, Faisal; Rankin, Rees B.; Greeley, Jeffrey; Curtiss, Larry A.

    2012-05-15

    A combination of first principles Density Functional Theory calculations and thermochemical scaling relationships are employed to estimate the thermochemistry and kinetics of methanol decomposition on unsupported subnanometer metal clusters. The approach uses binding energies of various atomic and molecular species, determined on the pure metal clusters, to develop scaling relationships that are then further used to estimate the methanol decomposition thermodynamics for a series of pure and bimetallic clusters with four atoms per cluster. Additionally, activation energy barriers are estimated from Brønsted–Evans–Polanyi plots relating transition and final state energies on these clusters. The energetic results are combined with a simple, microkinetically-inspired rate expression to estimate reaction rates as a function of important catalytic descriptors, including the carbon and atomic oxygen binding energies to the clusters. Finally, based on these analyses, several alloy clusters are identified as promising candidates for the methanol decomposition reaction.

  7. Effects of dynamic heterogeneity and density scaling of molecular dynamics on the relationship among thermodynamic coefficients at the glass transition

    SciTech Connect

    Koperwas, K. Grzybowski, A.; Grzybowska, K.; Wojnarowska, Z.; Paluch, M.

    2015-07-14

    In this paper, we define and experimentally verify thermodynamic characteristics of the liquid-glass transition, taking into account a kinetic origin of the process. Using the density scaling law and the four-point measure of the dynamic heterogeneity of molecular dynamics of glass forming liquids, we investigate contributions of enthalpy, temperature, and density fluctuations to spatially heterogeneous molecular dynamics at the liquid-glass transition, finding an equation for the pressure coefficient of the glass transition temperature, dTg/dp. This equation combined with our previous formula for dTg/dp, derived solely from the density scaling criterion, implies a relationship among thermodynamic coefficients at Tg. Since this relationship and both the equations for dTg/dp are very well validated using experimental data at Tg, they are promising alternatives to the classical Prigogine-Defay ratio and both the Ehrenfest equations in case of the liquid-glass transition.

  8. The Multidimensional Media Influence Scale: confirmatory factor structure and relationship with body dissatisfaction among African American and Anglo American children.

    PubMed

    Harrison, Kristen

    2009-06-01

    The Multidimensional Media Influence Scale (MMIS; Cusumano & Thompson, 2001). Media influence and body image in 8-11-year-old boys and girls: A preliminary report on the multidimensional media influence scale. International Journal of Eating Disorders, 29, 37-44) is a child-appropriate, 3-factor scale designed to assess perceived media influence on body image. It has been used in studies exploring the relationship between the entire scale as well as its subscales (awareness, internalization, and pressure) and variables related to body image. However, the 3-factor structure of the scale has never been confirmed via confirmatory factor analysis (CFA), nor has the scale been evaluated with a racially diverse sample of children. This paper reports the results of CFAs establishing the multidimensionality of the scale and the unidimensionality of its subscales among a sample of 661 girls and boys aged 7-12 years, primarily African American and Anglo American. The pressure factor of the MMIS predicted the idealization of a thinner current (child) and future (adult) body both cross-sectionally and one year later for girls and for Anglo American children. PMID:19447694

  9. Leaf longevity as a normalization constant in allometric predictions of plant production.

    PubMed

    Kikuzawa, Kihachiro; Seiwa, Kenji; Lechowicz, Martin J

    2013-01-01

    In metabolic scaling theory the size-dependence of plant processes is described by a power function of form Y=Y o M (θ) where Y is a characteristic such as plant productivity that changes with plant size (M) raised to the θ (th) power and Y o is a normalization constant that adjusts the general relationship across environments and species. In essence, the theory considers that the value of θ arises in the size-dependent relationship between leaf area and vascular architecture that influences plant function and that Y o modulates this general relationship to account for ecological and evolutionary effects on the exchange of resources between plant and environment. Enquist and colleagues have shown from first principles that Y o is a function of carbon use efficiency, the carbon fraction of a plant, the area-specific carbon assimilation rate of a leaf, the laminar area of a leaf, and the mass of a leaf. We show that leaf longevity provides a functional integration of these traits that can serve as a simpler normalization in scaling plant productivity for individual species and potentially for mixed-species communities as well. PMID:24312595

  10. Sap Flow Estimate Of Watershed-Scale Transpiration

    NASA Astrophysics Data System (ADS)

    Kumagai, T.; Aoki, S.; Shimizu, T.; Otsuki, K.

    2006-12-01

    The present study examined how to obtain sufficient information to extrapolate watershed-scale transpiration in a Japanese cedar (Cryptomeria japonica D. Don) forest from sap flow measurements of available individual trees. In this study, we conducted measurements of tree biometrics and tree-to-tree and radial variations in xylem sap flux density (Fd) in two different stand plots, an upper slope plot (UP) and lower slope plot (LP), during the growing season with significant variations in environmental factors. The manner in which the mean stand sap flux density (JS) and tree stem allometric relationship (diameter at breast height (DBH) versus sapwood area (AS_tree)) vary between the two stands along the slope of the watershed was then investigated. After these analyses, appropriate sample sizes for estimations of representative JS values in the stand were also determined. The results demonstrated that a unique or general function allowed description of the allometric relationship along the slope, but the data for its formulation needed to be obtained in both UP and LP. They also revealed that JS in UP and LP were almost the same during the study period despite differences in tree density and size between the two plots. This implies that JS measured in a partial stand within a watershed is a reasonable estimator of the values of other stands, and that stand sapwood area calculated by AS_tree is a strong determinant of water-use in a forest watershed. To estimate JS in both an UP and LP, at least 10 trees should be sampled, but not necessarily more than this.

  11. Career Adapt-Abilities Scale--Brazilian Form: Psychometric Properties and Relationships to Personality

    ERIC Educational Resources Information Center

    Teixeira, Marco Antonio Pereira; Bardagi, Marucia Patta; Lassance, Maria Celia Pacheco; Magalhaes, Mauro de Oliveira; Duarte, Maria Eduarda

    2012-01-01

    The Career Adapt-Abilities Scale--Brazilian Form (CAASBrazil) consists of four scales which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. Internal consistency estimates for the subscale and total scores ranged from good to excellent. The…

  12. Career Adapt-Abilities Scale--Portugal Form: Psychometric Properties and Relationships to Employment Status

    ERIC Educational Resources Information Center

    Duarte, M. Eduarda; Soares, M. C.; Fraga, S.; Rafael, M.; Lima, M. R.; Paredes, I.; Agostinho, R.; Djalo, A.

    2012-01-01

    The Career-Adaptabilities Scale (CAAS)--Portugal Form consists of four scales, each with seven items, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. Internal consistency estimates for the subscale and total scores ranged from good to…

  13. An analysis of tooth and body size relationship in five primate taxa.

    PubMed

    Wood, B A

    1979-01-01

    The strength and the nature of the covariance between tooth and body size was investigated in Homo, Gorilla, Pan, Papio and Colobus. When sexes are combined in each taxon, the correlations are strong enough to compare the allometry coefficients of taxa, and the non-human taxa show a sufficiently strong linear relationship to compute 'interspecific' allometry coefficients. Allometry coefficients for each variable were not uniform among the taxa, and coefficients also differed from one variable to another. Computed 'intra' and 'inter' specific allometry coefficients from these data suggest that canine size will usually scale at a higher level than molar crown area, which is at most isometric, and not positively allometric with respect to body size. The consequence is that larger representatives of a taxon would be expected to combine relatively larger canines with a proportional, or relatively smaller, molar crown area. It is pointed out that these differences do not correspond to those found between 'gracile' and 'robust' australopithecines. PMID:116945

  14. Multi-scale analysis of relationship between landscape pattern and urban river water quality in different seasons

    PubMed Central

    Xiao, Rui; Wang, Guofeng; Zhang, Qianwen; Zhang, Zhonghao

    2016-01-01

    Water quality is highly dependent on the landscape characteristics. In this study, we investigated the relationships between water quality and landscape pattern (composition and configuration) in Huzhou City, China. The water quality variables, including pH, dissolved oxygen (DO), chemical oxygen demand (CODMn), Biochemical Oxygen Demand (BOD), NH3-N, petroleum, dissolved total phosphorus (DTP), and total nitrogen (TN) in low water, normal water and flood periods were identified by investigating 34 sampling sites in Huzhou City during the period from 2001 to 2007. Landscape composition and landscape configuration metrics were calculated for different scales. It was found that scales and seasons both play important role when analyzing the relationships between landscape characteristics of different land use types. The results implied that some water quality parameters such as CODMn, petroleum are more polluted in flood period than the other two seasons at different scales, while DTP and TN are more polluted in low water period. Influences of different landscape metrics on water quality should operate at different spatial scales. The results shown in this paper will effectively provide scientific basis for the policy making in sustainable development of water environment. PMID:27147104

  15. Multi-scale analysis of relationship between landscape pattern and urban river water quality in different seasons

    NASA Astrophysics Data System (ADS)

    Xiao, Rui; Wang, Guofeng; Zhang, Qianwen; Zhang, Zhonghao

    2016-05-01

    Water quality is highly dependent on the landscape characteristics. In this study, we investigated the relationships between water quality and landscape pattern (composition and configuration) in Huzhou City, China. The water quality variables, including pH, dissolved oxygen (DO), chemical oxygen demand (CODMn), Biochemical Oxygen Demand (BOD), NH3-N, petroleum, dissolved total phosphorus (DTP), and total nitrogen (TN) in low water, normal water and flood periods were identified by investigating 34 sampling sites in Huzhou City during the period from 2001 to 2007. Landscape composition and landscape configuration metrics were calculated for different scales. It was found that scales and seasons both play important role when analyzing the relationships between landscape characteristics of different land use types. The results implied that some water quality parameters such as CODMn, petroleum are more polluted in flood period than the other two seasons at different scales, while DTP and TN are more polluted in low water period. Influences of different landscape metrics on water quality should operate at different spatial scales. The results shown in this paper will effectively provide scientific basis for the policy making in sustainable development of water environment.

  16. Multi-scale analysis of relationship between landscape pattern and urban river water quality in different seasons.

    PubMed

    Xiao, Rui; Wang, Guofeng; Zhang, Qianwen; Zhang, Zhonghao

    2016-01-01

    Water quality is highly dependent on the landscape characteristics. In this study, we investigated the relationships between water quality and landscape pattern (composition and configuration) in Huzhou City, China. The water quality variables, including pH, dissolved oxygen (DO), chemical oxygen demand (CODMn), Biochemical Oxygen Demand (BOD), NH3-N, petroleum, dissolved total phosphorus (DTP), and total nitrogen (TN) in low water, normal water and flood periods were identified by investigating 34 sampling sites in Huzhou City during the period from 2001 to 2007. Landscape composition and landscape configuration metrics were calculated for different scales. It was found that scales and seasons both play important role when analyzing the relationships between landscape characteristics of different land use types. The results implied that some water quality parameters such as CODMn, petroleum are more polluted in flood period than the other two seasons at different scales, while DTP and TN are more polluted in low water period. Influences of different landscape metrics on water quality should operate at different spatial scales. The results shown in this paper will effectively provide scientific basis for the policy making in sustainable development of water environment. PMID:27147104

  17. Energy and the Scaling of Animal Space Use.

    PubMed

    Tamburello, Natascia; Côté, Isabelle M; Dulvy, Nicholas K

    2015-08-01

    Daily animal movements are usually limited to a discrete home range area that scales allometrically with body size, suggesting that home-range size is shaped by metabolic rates and energy availability across species. However, there is little understanding of the relative importance of the various mechanisms proposed to influence home-range scaling (e.g., differences in realm productivity, thermoregulation, locomotion strategy, dimensionality, trophic guild, and prey size) and whether these extend beyond the commonly studied birds and mammals. We derive new home-range scaling relationships for fishes and reptiles and use a model-selection approach to evaluate the generality of home-range scaling mechanisms across 569 vertebrate species. We find no evidence that home-range allometry varies consistently between aquatic and terrestrial realms or thermoregulation strategies, but we find that locomotion strategy, foraging dimension, trophic guild, and prey size together explain 80% of the variation in home-range size across vertebrates when controlling for phylogeny and tracking method. Within carnivores, smaller relative prey size among gape-limited fishes contributes to shallower scaling relative to other predators. Our study reveals how simple morphological traits and prey-handling ability can profoundly influence individual space use, which underpins broader-scale patterns in the spatial ecology of vertebrates. PMID:26655149

  18. Upscaling Self-Sustaining Treatment for Active Remediation (STAR): Experimental Study of Scaling Relationships for Smouldering Combustion to Remediate Soil

    NASA Astrophysics Data System (ADS)

    Kinsman, L.; Gerhard, J.; Torero, J.; Scholes, G.; Murray, C.

    2013-12-01

    scale experiments, including: peak temperatures, velocities and thicknesses of the smouldering front, rates of mass destruction of the contaminant, and rates of gaseous emissions during combustion. Additionally, upward and downward smouldering experiments were compared at the column scale to assess the significance of buoyant flow effects. An understanding of these scaling relationships will provide important information to aid in the design of field-scale applications of STAR.

  19. An investigation of relationships between meso- and synoptic-scale phenomena

    NASA Technical Reports Server (NTRS)

    Scoggins, J. R.; Wood, J. E.; Fuelberg, H. E.; Read, W. L.

    1972-01-01

    Methods based on the vorticity equation, the adiabatic method, the curvature of the vertical wind profile, and the structure of synoptic waves are used to determine areas of positive vertical motion in the mid-troposphere for a period in each season. Parameters indicative of low-level moisture and conditional instability are areas in which mesoscale systems may be present. The best association between mesoscale and synoptic-scale phenomena was found for a period during December when synoptic-scale systems were well developed. A good association between meso- and synoptic-scale events also was found for a period during March, while the poorest association was found for a June period. Daytime surface heating apparently is an important factor in the formation of mesoscale systems during the summer. It is concluded that the formation of mesoscale phenomena may be determined essentially from synoptic-scale conditions during winter, late fall, and early spring.

  20. Long-term and large-scale perspectives on the relationship between biodiversity and ecosystem functioning

    USGS Publications Warehouse

    Symstad, A.J.; Chapin, F. S., III; Wall, D.H.; Gross, K.L.; Huenneke, L.F.; Mittelbach, G.G.; Peters, D.P.C.; Tilman, D.

    2003-01-01

    In a growing body of literature from a variety of ecosystems is strong evidence that various components of biodiversity have significant impacts on ecosystem functioning. However, much of this evidence comes from short-term, small-scale experiments in which communities are synthesized from relatively small species pools and conditions are highly controlled. Extrapolation of the results of such experiments to longer time scales and larger spatial scales - those of whole ecosystems - is difficult because the experiments do not incorporate natural processes such as recruitment limitation and colonization of new species. We show how long-term study of planned and accidental changes in species richness and composition suggests that the effects of biodiversity on ecosystem functioning will vary over time and space. More important, we also highlight areas of uncertainty that need to be addressed through coordinated cross-scale and cross-site research.

  1. Relationship of the Gesell Developmental Exam and the Bracken Basic Concept Scale to Academic Achievement.

    ERIC Educational Resources Information Center

    Sterner, Anne G.; McCallum, R. Steve

    1988-01-01

    Administered the Gesell Development Exam and the Bracken Basic Concept Scale (BBCS) to kindergarten graduates (N=80). Found the BBCS may be a better predictor of achievement from a current state of readiness. (Author/ABL)

  2. General Relationship of Global Topology, Local Dynamics, and Directionality in Large-Scale Brain Networks

    PubMed Central

    Moon, Joon-Young; Lee, UnCheol; Blain-Moraes, Stefanie; Mashour, George A.

    2015-01-01

    The balance of global integration and functional specialization is a critical feature of efficient brain networks, but the relationship of global topology, local node dynamics and information flow across networks has yet to be identified. One critical step in elucidating this relationship is the identification of governing principles underlying the directionality of interactions between nodes. Here, we demonstrate such principles through analytical solutions based on the phase lead/lag relationships of general oscillator models in networks. We confirm analytical results with computational simulations using general model networks and anatomical brain networks, as well as high-density electroencephalography collected from humans in the conscious and anesthetized states. Analytical, computational, and empirical results demonstrate that network nodes with more connections (i.e., higher degrees) have larger amplitudes and are directional targets (phase lag) rather than sources (phase lead). The relationship of node degree and directionality therefore appears to be a fundamental property of networks, with direct applicability to brain function. These results provide a foundation for a principled understanding of information transfer across networks and also demonstrate that changes in directionality patterns across states of human consciousness are driven by alterations of brain network topology. PMID:25874700

  3. Gender-based differences in the shape of the human corpus callosum are associated with allometric variations

    PubMed Central

    Bruner, Emiliano; de la Cuétara, José Manuel; Colom, Roberto; Martin-Loeches, Manuel

    2012-01-01

    The corpus callosum displays considerable morphological variability between individuals. Although some characteristics are thought to differ between male and female brains, there is no agreement regarding the source of this variation. Biomedical imaging and geometric morphometrics have provided tools to investigate shape and size variation in terms of integration and correlation. Here we analyze variations at the midsagittal outline of the corpus callosum in a sample of 102 young adults in order to describe and quantify the pattern of covariation associated with its morphology. Our results suggest that the shape of the corpus callosum is characterized by low levels of morphological integration, which explains the large variability. In larger brains, a minor allometric component involves a relative reduction of the splenium. Small differences between males and?females are associated with this allometric pattern, induced primarily by size variation rather than gender-specific characteristics. PMID:22296183

  4. Gender-based differences in the shape of the human corpus callosum are associated with allometric variations.

    PubMed

    Bruner, Emiliano; de la Cuétara, José Manuel; Colom, Roberto; Martin-Loeches, Manuel

    2012-04-01

    The corpus callosum displays considerable morphological variability between individuals. Although some characteristics are thought to differ between male and female brains, there is no agreement regarding the source of this variation. Biomedical imaging and geometric morphometrics have provided tools to investigate shape and size variation in terms of integration and correlation. Here we analyze variations at the midsagittal outline of the corpus callosum in a sample of 102 young adults in order to describe and quantify the pattern of covariation associated with its morphology. Our results suggest that the shape of the corpus callosum is characterized by low levels of morphological integration, which explains the large variability. In larger brains, a minor allometric component involves a relative reduction of the splenium. Small differences between males and?females are associated with this allometric pattern, induced primarily by size variation rather than gender-specific characteristics. PMID:22296183

  5. Proctophantastes nettastomatis (Digenea: Zoogonidae) from Vanuatu deep-sea fish: new morphological features, allometric growth, and phenotypic plasticity aspects.

    PubMed

    Mouahid, Gabriel; Faliex, Elisabeth; Allienne, Jean-François; Cribb, Thomas H; Bray, Rodney A

    2012-05-01

    The present paper deals with Proctophantastes nettastomatis (Digenea: Zoogonidae; Lepidophyllinae) found in the intestine of three species of deep-sea fish, Dicrolene longimana (Ophidiidae, Ophidiiformes), Bathyuroconger sp. (Congridae, Anguilliformes), and Venefica tentaculata (Nettastomatidae, Anguilliformes). The fish were collected near the islands of Espiritu Santo, Erromango, and Epi, respectively, in the archipelago of Vanuatu (Southern Pacific Ocean) at depths ranging from 561 to 990 m. Morphological and histological analyses showed that the Vanuatu specimens differ from Proctophantastes abyssorum, Proctophantastes gillissi, Proctophantastes glandulosum, Proctophantastes infundibulum, and Proctophantastes brayi but are close to P. nettastomatis discovered in Suruga Bay, Japan. P. nettastomatis is redescribed based both on the observations of our specimens and of the Japanese holotype and paratype. The morphological variability of the species is described. Morphometric data allowed the identification of positive allometric growth for the hindbody, negative allometric growth for the ventral sucker, and a growth phenotypic plasticity between Ophidiiformes and Anguilliformes definitive hosts. PMID:22089085

  6. Practical Dyspnea Assessment: Relationship Between the 0–10 Numerical Rating Scale and the Four-Level Categorical Verbal Descriptor Scale of Dyspnea Intensity

    PubMed Central

    Wysham, Nicholas G.; Miriovsky, Benjamin J.; Currow, David C.; Herndon, James E.; Samsa, Gregory P.; Wilcock, Andrew; Abernethy, Amy P.

    2016-01-01

    Context Measurement of dyspnea is important for clinical care and research. Objectives To characterize the relationship between the 0–10 Numerical Rating Scale (NRS) and four-level categorical Verbal Descriptor Scale (VDS) for dyspnea assessment. Methods This was a substudy of a double-blind randomized controlled trial comparing palliative oxygen to room air for relief of refractory breathlessness in patients with life-limiting illness. Dyspnea was assessed with both a 0–10 NRS and a four-level categorical VDS over the one-week trial. NRS and VDS responses were analyzed in cross section and longitudinally. Relationships between NRS and VDS responses were portrayed using descriptive statistics and visual representations. Results Two hundred twenty-six participants contributed responses. At baseline, mild and moderate levels of breathlessness were reported by 41.9% and 44.6% of participants, respectively. NRS scores demonstrated increasing mean and median levels for increasing VDS intensity, from a mean (SD) of 0.6 (±1.04) for VDS none category to 8.2 (1.4) for VDS severe category. The Spearman correlation coefficient was strong at 0.78 (P < 0.0001). Based on the distribution of NRS scores within VDS categories, we calculated test characteristics of two different cutpoint models. Both models yielded 75% correct translations from NRS to VDS; however, Model A was more sensitive for moderate or greater dyspnea, with fewer misses downcoded. Conclusion There is strong correlation between VDS and NRS measures for dyspnea. Proposed practical cutpoints for the relationship between the dyspnea VDS and NRS are 0 for none, 1–4 for mild, 5–8 for moderate, and 9–10 for severe. PMID:26004401

  7. Predicting multi-scale relationships between geomorphology and bedrock geology of the rocky intertidal in Central and Northern California

    NASA Astrophysics Data System (ADS)

    Wheeler, A.; Aiello, I. W.

    2014-12-01

    Substratum geology is fundamental in shaping rocky shore morphology. Specific lithologies have various responses to wave action, tectonic features (e.g. fractures, faults) and sedimentary structures (e.g. bedding), creating distinctive weathering profiles. Along with local oceanography and climate forcing, different rock substrata create coastal morphologies that can vary distinctly between scales, ranging from mm to km. Despite the complexity of the system, qualitative observations show coastal areas with similar rock types share similar geomorphologies. Thus, a statistic relationship between geomorphology (expressed for instance by surface parameter rugosity) and geology can be envisaged. There are multiple benefits of finding such a relationship, as rocky intertidal geomorphology can be an important determinant in which organisms can settle, grow, and survive in near shore communities: allowing the prediction of geomorphologic parameters determining coastal ecology solely based on substratum geology, a crucial aspect in guiding the selection of marine protected areas. This study presents preliminary results of multi-scale geospatial surveys (cm to tens of meters) of rocky intertidal outcrops from Central to Northern California using a Terrestrial Laser Scanner. The outcrops investigated are representative of the most common igneous and sedimentary rocks in California (granitoids, conglomerates, sandstones, mudstones) and metamorphic units. The statistical analysis of the survey data support the hypothesis that surface properties can change significantly with changing scale, each rock type having distinct surface characteristics which are similar to comparable lithologies exposed at different locations. These scale dependent variations are controlled by different lithologic and structural characteristics of the outcrop in question. Our data also suggests lithologic variability within a rock unit could be a very significant factor in controlling changes in

  8. [The relationship between perceived personality and Ieading/following roles in university students' close friendships, using Gitaigo personality scale].

    PubMed

    Komatsu, Koji; Mukoyama, Yasuyo; Nishioka, Miwa; Sakai, Keiko

    2016-02-01

    Based on the recently developed Gitaigo personality scale (Komatsu, Sakai, Nishioka, & Mukoyama, 2012), we investigated the relationship between perceived personality and leading/following roles in close friend dyads. Primary participants rated their own and one of their close friend's personality with Gitaigo personality scale. They also described who takes the role of leader in the relationship with the friend they rated. When one in the pair is reported as leader, the other is considered as follower. Subsidiary participants who were cited as close friends rated their own personality. Our analysis of the 215 pairs showed that the participants taking the role of follower were rated higher in the traits of Cowardliness and Mildness by the primary participants. Regarding Mildness, this tendency was also clear in subsidiary participants' self-ratings. Primary participants rated the Preciseness and Candidness of their friends lower if their friend was considered a follower. Gitaigo personality scale describes the perceived personality well, at least for several traits. PMID:26964374

  9. Testing the robustness, to changes in process, of a scaling relationship between soil grading and geomorphology using a pedogenesis model

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.; Welivitiya, W. D. D. P.; Hancock, G. R.

    2014-12-01

    Using the mARM1D pedogenesis model (which simulated armouring and weathering processes on a hillslope) previous work by Cohen found a strong log-log linear relationship between the size distribution of the soil (e.g. d50), the contributing area and the local slope. However, Cohen performed his simulations using only one set of grading data, one climate, one geology and did his simulations over a relatively limited range of area and slope combinations. A model based on mARM, called SSSPAM, that generalises the modelled processes has been developed, and calibrated to mARM. This calibration was used as the starting point for a parametric study of the robustness to changes in environmental conditions and weathering conditions of the area-slope and d50 relationship, different initial soil gradings and weathering conditions, different geology, and a broader range of area and slope combinations. This parametric study assessed the influence of changes in the model parameters on the soil evolution results. These simulations confirmed the robustness of the area-slope and d50 relationship discovered by Cohen using mARM. We also demonstrated that the area-slope-diameter relationship is not only true for d50 but for the entire grading range (e.g. d10, d90). The results strengthen our confidence in the generality of the log-log linear scaling relationship between area, slope and soil grading. The paper will present the results of our parametric study and will highlight the potential uses of the relationship for digital soil mapping and better characterization of soils in environmental models.

  10. Scaling CO2-photosynthesis relationships from the leaf to the canopy.

    PubMed

    Amthor, J S

    1994-03-01

    Responses of individual leaves to short-term changes in CO2 partial pressure have been relatively well studied. Whole-plant and plant community responses to elevated CO2 are less well understood and scaling up from leaves to canopies will be complicated if feedbacks at the small scale differ from feedbacks at the large scale. Mathematical models of leaf, canopy, and ecosystem processes are important tools in the study of effects on plants and ecosystems of global environmental change, and in particular increasing atmospheric CO2, and might be used to scale from leaves to canopies. Models are also important in assessing effects of the biosphere on the atmosphere. Presently, multilayer and big leaf models of canopy photosynthesis and energy exchange exist. Big leaf models - which are advocated here as being applicable to the evaluation of impacts of 'global change' on the biosphere - simplify much of the underlying leaf-level physics, physiology, and biochemistry, yet can retain the important features of plant-environment interactions with respect to leaf CO2 exchange processes and are able to make useful, quantitative predictions of canopy and community responses to environmental change. The basis of some big leaf models of photosynthesis, including a new model described herein, is that photosynthetic capacity and activity are scaled vertically within a canopy (by plants themselves) to match approximately the vertical profile of PPFD. The new big leaf model combines physically based models of leaf and canopy level transport processes with a biochemically based model of CO2 assimilation. Predictions made by the model are consistent with canopy CO2 exchange measurements, although a need exists for further testing of this and other canopy physiology models with independent measurements of canopy mass and energy exchange at the time scale of 1 h or less. PMID:24311128

  11. Relationship between the Averaged Deposition Rate Coefficients for Colloids in a Single Pore and Various Pore-scale Parameters

    NASA Astrophysics Data System (ADS)

    Narayanan, S.; Mohan Kumar, M.; Hassanizadeh, S. M.; Raoof, A.

    2014-12-01

    rate coefficient vs the parameters describing DLVO energy profile, and a power law relationship between colloid attachment rate coefficient vs the average pore-water velocity. The current model forms the building block for upscaling colloid transport from pore scale to Darcy scale using Pore Network Modeling.

  12. Scaling Relationships for Adsorption Energies of C2 Hydrocarbons on Transition Metal Surfaces

    SciTech Connect

    Jones, G

    2011-08-18

    Using density functional theory calculations we show that the adsorption energies for C{sub 2}H{sub x}-type adsorbates on transition metal surfaces scale with each other according to a simple bond order conservation model. This observation generalizes some recently recognized adsorption energy scaling laws for AH{sub x}-type adsorbates to unsaturated hydrocarbons and establishes a coherent simplified description of saturated as well as unsaturated hydrocarbons adsorbed on transition metal surfaces. A number of potential applications are discussed. We apply the model to the dehydrogenation of ethane over pure transition metal catalysts. Comparison with the corresponding full density functional theory calculations shows excellent agreement.

  13. Scales

    MedlinePlus

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Eczema , ringworm , and psoriasis ...

  14. Measuring Social Relationships in Different Social Systems: The Construction and Validation of the Evaluation of Social Systems (EVOS) Scale.

    PubMed

    Aguilar-Raab, Corina; Grevenstein, Dennis; Schweitzer, Jochen

    2015-01-01

    Social interactions have gained increasing importance, both as an outcome and as a possible mediator in psychotherapy research. Still, there is a lack of adequate measures capturing relational aspects in multi-person settings. We present a new measure to assess relevant dimensions of quality of relationships and collective efficacy regarding interpersonal interactions in diverse personal and professional social systems including couple partnerships, families, and working teams: the EVOS. Theoretical dimensions were derived from theories of systemic family therapy and organizational psychology. The study was divided in three parts: In Study 1 (N = 537), a short 9-item scale with two interrelated factors was constructed on the basis of exploratory factor analysis. Quality of relationship and collective efficacy emerged as the most relevant dimensions for the quality of social systems. Study 2 (N = 558) confirmed the measurement model using confirmatory factor analysis and established validity with measures of family functioning, life satisfaction, and working team efficacy. Measurement invariance was assessed to ensure that EVOS captures the same latent construct in all social contexts. In Study 3 (N = 317), an English language adaptation was developed, which again confirmed the original measurement model. The EVOS is a theory-based, economic, reliable, and valid measure that covers important aspects of social relationships, applicable for different social systems. It is the first instrument of its kind and an important addition to existing measures of social relationships and related outcome measures in therapeutic and other counseling settings involving multiple persons. PMID:26200357

  15. Measuring Social Relationships in Different Social Systems: The Construction and Validation of the Evaluation of Social Systems (EVOS) Scale

    PubMed Central

    Aguilar-Raab, Corina; Grevenstein, Dennis; Schweitzer, Jochen

    2015-01-01

    Social interactions have gained increasing importance, both as an outcome and as a possible mediator in psychotherapy research. Still, there is a lack of adequate measures capturing relational aspects in multi-person settings. We present a new measure to assess relevant dimensions of quality of relationships and collective efficacy regarding interpersonal interactions in diverse personal and professional social systems including couple partnerships, families, and working teams: the EVOS. Theoretical dimensions were derived from theories of systemic family therapy and organizational psychology. The study was divided in three parts: In Study 1 (N = 537), a short 9-item scale with two interrelated factors was constructed on the basis of exploratory factor analysis. Quality of relationship and collective efficacy emerged as the most relevant dimensions for the quality of social systems. Study 2 (N = 558) confirmed the measurement model using confirmatory factor analysis and established validity with measures of family functioning, life satisfaction, and working team efficacy. Measurement invariance was assessed to ensure that EVOS captures the same latent construct in all social contexts. In Study 3 (N = 317), an English language adaptation was developed, which again confirmed the original measurement model. The EVOS is a theory-based, economic, reliable, and valid measure that covers important aspects of social relationships, applicable for different social systems. It is the first instrument of its kind and an important addition to existing measures of social relationships and related outcome measures in therapeutic and other counseling settings involving multiple persons. PMID:26200357

  16. The temporal dynamics of a scaling relationship between soil grading and landscape geomorphology using a pedogenesis model

    NASA Astrophysics Data System (ADS)

    Welivitiya, Dimuth; Willgoose, Garry; Hancock, Greg

    2015-04-01

    Using the mARM3D pedogenesis model (which simulated armouring and weathering processes on a hillslope) previous work by Cohen and the coauthors of this abstract found a strong log-log linear relationship between the particle size distribution of the soil (e.g. d50), the contributing area and the local slope. In recent work using our SSSPAM pedogenesis model (a generalisation of mARM3D) we have confirmed this relationship is robust against changes in climate and geology and is also true for more general grading properties of the soil at the surface (e.g. d10, d90). However, this previous work was for equilibrium soils and time invariant landforms. In this presentation we will extend this work to show the effect of temporal dynamics in the pedogenesis model by exploring the spatial organisation of the time varying behaviour of soil grading. We will show how the within-profile weathering processes change the variation with depth of the soil grading, and how the spatial variation of the soil surface and depth averaged grading properties change with the temporal dynamics. These results strengthen our confidence in the generality of the log-log linear scaling relationship between area, slope and soil grading. The paper will present the results of our simulations and will highlight the potential uses of the relationship for digital soil mapping and better characterization of soils in environmental models.

  17. The brief accessibility, responsiveness, and engagement (BARE) scale: a tool for measuring attachment behavior in couple relationships.

    PubMed

    Sandberg, Jonathan G; Busby, Dean M; Johnson, Susan M; Yoshida, Keitaro

    2012-12-01

    This article describes the purpose, reliability, validity, and potential clinical applications of the brief accessibility, responsiveness, and engagement (BARE) scale. In addition to focusing on the central attachment behaviors of accessibility and responsiveness, this instrument highlights the key role of engagement in couple bonding. The BARE is a short, systemic, self-report measure of attachment behaviors in couple relationships. Both classical testing theory and item response theory were used to test the psychometric properties of the instrument. The BARE demonstrated appropriate reliability and validity while maintaining its brevity and potential usefulness for clinicians and researchers. The BARE also accurately predicted the key relationship outcomes of stability and satisfaction. The data for this study were collected from the RELATE assessment (see www.relate-institute.org). PMID:23230982

  18. Career Adapt-Abilities Scale-France Form: Psychometric Properties and Relationships to Anxiety and Motivation

    ERIC Educational Resources Information Center

    Pouyaud, Jacques; Vignoli, Emmanuelle; Dosnon, Odile; Lallemand, Noelle

    2012-01-01

    The CAAS-France Form consists of four scales, each with six items, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. Internal consistency estimates for the subscale and total scores ranged from moderate to good. The factor structure was…

  19. RELATIONSHIPS BETWEEN JUVENILE WINTER FLOUNDER AND MULTIPLE-SCALE HABITAT VARIATION IN NARRAGANSETT BAY, RHODE ISLAND

    EPA Science Inventory

    A rapid random-sampling method was used to relate densities of juvenile winter flounder to multiple scales of habitat variation in Narragansett Bay and two nearby coastal lagoons in Rhode Island. We used a 1-m beam trawl with attached video camera, continuous GPS track overlay, ...

  20. Critical Thinking Motivational Scale: A Contribution to the Study of Relationship between Critical Thinking and Motivation

    ERIC Educational Resources Information Center

    Valenzuela, Jorge; Nieto, Ana M.; Saiz, Carlos

    2011-01-01

    Introduction: The present work reports the characteristics of an instrument measuring the degree of motivation that people possess to think critically. The "Critical Thinking Motivation Scales" ("CTMS") is based on a theoretical option that affords precedence to the perspective of motivation for over the perspective of dispositions. Motivation is…

  1. Decision to Leave Scale: Perceived Reasons to Stay in or Leave Violent Relationships

    ERIC Educational Resources Information Center

    Hendy, Helen M.; Eggen, Doreen; Gustitus, Cheryl; McLeod, Kelli C.; Ng, Phillip

    2003-01-01

    The 30-item Decision to Leave Scale (DLS) was developed with 631 college women and 420 college women and women in shelters. Seven DLS subscales emerged for concerns in deciding to stay or leave: Fear of Loneliness, Child Care Needs, Financial Problems, Social Embarrassment, Poor Social Support, Fear of Harm, Hopes Things Change. Mean internal…

  2. Cophylogenetic relationships between Anicetus parasitoids (Hymenoptera: Encyrtidae) and their scale insect hosts (Hemiptera: Coccidae)

    PubMed Central

    2013-01-01

    Background Numerous studies have investigated cospeciation between parasites and their hosts, but there have been few studies concerning parasitoids and insect hosts. The high diversity and host specialization observed in Anicetus species suggest that speciation and adaptive radiation might take place with species diversification in scale insect hosts. Here we examined the evolutionary history of the association between Anicetus species and their scale insect hosts via distance-based and tree-based methods. Results A total of 94 Anicetus individuals (nine parasitoid species) and 113 scale insect individuals (seven host species) from 14 provinces in China were collected in the present study. DNA sequence data from a mitochondrial gene (COI) and a nuclear ribosomal gene (28S D2 region) were used to reconstruct the phylogenies of Anicetus species and their hosts. The distance-based analysis showed a significant fit between Anicetus species and their hosts, but tree-based analyses suggested that this significant signal could be observed only when the cost of host-switching was high, indicating the presence of parasite sorting on related host species. Conclusions This study, based on extensive rearing of parasitoids and species identification, provides strong evidence for a prevalence of sorting events and high host specificity in the genus Anicetus, offering insights into the diversification process of Anicetus species parasitizing scale insects. PMID:24365056

  3. Foggy Faithfulness: Relationship Quality, Religiosity, and the Perceptions of Dating Infidelity Scale in an Adult Sample

    ERIC Educational Resources Information Center

    Mattingly, Brent A.; Wilson, Karen; Clark, Eddie M.; Bequette, Amanda W.; Weidler, Daniel J.

    2010-01-01

    The goals of the current study were to (a) replicate the factor structure of the Perceptions of Dating Infidelity Scale (PDIS) with a sample of older adults, (b) examine whether religiosity and relational variables (e.g., satisfaction, commitment) were correlates of perceptions of infidelity, and (c) examine unique predictors of ratings of…

  4. EFFECTS OF SCALE ON LAND USE AND WATER QUALITY RELATIONSHIPS: A LONGITUDINAL BASIN-WIDE PERSPECTIVE

    EPA Science Inventory

    Human land use is a major source of change in catchments in developing areas. To better anticipate the long-term effects of growth, land use planning requires estimates of how changes in land use will affect ecosystem processes and patterns across multiple scales of space and ti...

  5. The Behavior Observation Scale for Autism (BOS): Relationship of Frequency of Behavior to IQ.

    ERIC Educational Resources Information Center

    Freeman, B. J.; And Others

    The Behavior Observation Scale (BOS) was administered to 53 autistic children, 35 mentally retarded children matched for MA, and 33 normal children (all 2 to 5 years old) in an attempt to quantify autistic behavior. Ss were observed 3 days for 3 minutes through a one way mirror in a playroom setting where occurrence of 67 behaviors on the BOS was…

  6. The Relationship between Lexicon Rankings and Item Difficulty on the Bracken Basic Concept Scale.

    ERIC Educational Resources Information Center

    Frisby, Craig L.

    1992-01-01

    Analysis of the Bracken Basic Concept Scale (BBCS) indicated that all subtests except two (Quantity and Time) showed statistically significant correlations between item difficulty and frequency of concept words. Administration of the BBCS to 36 first graders revealed that most concept words showed expected item discrimination indices. (Author/JDD)

  7. A relationship between indigenous impurity elements and protective oxide scale adherence characteristics

    NASA Astrophysics Data System (ADS)

    Smeggil, J. G.; Funkenbusch, A. W.; Bornstein, N. S.

    1986-06-01

    A new and a radically different mechanism to account for the beneficial effects that small additions of elements such as yttrium have on the adherence of oxide scales is proposed. It has been long:known and has been reaffirmed here that indigenous impurities such as sulfur, known to be present at tramp levels (<100 ppm) within nickel and nickel-based alloys, can segregate to metal surfaces. However, here it has been disclosed that such sulfur segregation can also markedly affect the adherence of the protective oxide scale. In the absence of elements like yttrium, such segregation effects weaken the bond between the protective scale and the substrate metal. The role of the yttrium is to interact with such indigenous sulfur to form a refractory sulfide. This interaction lessens the amount of sulfur available to segregate to and concentrate at the critical scale-metal interface. Results reported here have focused on sulfur because sulfur has been long known to be a common tramp impurity in nickel and nickel-based alloys. However other elements, e.g., phosphorus, chlorine, etc., could very probably produce similar effects. The results of experiments involving Auger spectroscopy, optical, scanning electron microscopy, scanning electron microprobe, and scanning transmission electron microscopy techniques in conjunction with isothermal and cyclic oxidation testing which have led us to propose this mechanism are presented.

  8. Encephalization and allometric trajectories in the genus Homo: Evidence from the Neandertal and modern lineages

    PubMed Central

    Bruner, Emiliano; Manzi, Giorgio; Arsuaga, Juan Luis

    2003-01-01

    The term “encephalization” is commonly used to describe an enlargement in brain size, considered as either absolute endocranial volumes or relative values in relation to body size. It is widely recognized that a considerable endocranial expansion occurred throughout the evolution of the genus Homo. This article aims to evaluate whether this phenomenon was the outcome of distinct evolutionary lineages, reaching similar brain expansions but through different trajectories. Endocranial morphology was studied in a sample of fossil hominines by multivariate approaches using both traditional metrics and geometric morphometrics. The analysis was focused on the transition from a generalized archaic pattern within the genus Homo to the modern morphology and compared with changes that occurred along the Neandertal lineage. The main result was the identification of two different evolutionary trajectories, in which a similar expansion in endocranial size has been reached by different changes in shape. Along the Neandertal lineage we observed maintenance of an “archaic” endocranial model, in which a large amount of variability is based on a single allometric trend. By contrast, when modern endocasts were compared with nonmodern ones, we found important differences apparently led by a parietal expansion. In this light, the origin of our species may have represented the opportunity to surpass the constraints imposed on encephalization by the ontogenetic pattern shared by nonmodern Homo representatives. PMID:14673084

  9. Final Harvest of Above-Ground Biomass and Allometric Analysis of the Aspen FACE Experiment

    SciTech Connect

    Mark E. Kubiske

    2013-04-15

    The Aspen FACE experiment, located at the US Forest Service Harshaw Research Facility in Oneida County, Wisconsin, exposes the intact canopies of model trembling aspen forests to increased concentrations of atmospheric CO2 and O3. The first full year of treatments was 1998 and final year of elevated CO2 and O3 treatments is scheduled for 2009. This proposal is to conduct an intensive, analytical harvest of the above-ground parts of 24 trees from each of the 12, 30 m diameter treatment plots (total of 288 trees) during June, July & August 2009. This above-ground harvest will be carefully coordinated with the below-ground harvest proposed by D.F. Karnosky et al. (2008 proposal to DOE). We propose to dissect harvested trees according to annual height growth increment and organ (main stem, branch orders, and leaves) for calculation of above-ground biomass production and allometric comparisons among aspen clones, species, and treatments. Additionally, we will collect fine root samples for DNA fingerprinting to quantify biomass production of individual aspen clones. This work will produce a thorough characterization of above-ground tree and stand growth and allocation above ground, and, in conjunction with the below ground harvest, total tree and stand biomass production, allocation, and allometry.

  10. Comparative Allometric Growth of the Mimetic Ephippid Reef Fishes Chaetodipterus faber and Platax orbicularis.

    PubMed

    Barros, Breno; Sakai, Yoichi; Pereira, Pedro H C; Gasset, Eric; Buchet, Vincent; Maamaatuaiahutapu, Moana; Ready, Jonathan S; Oliveira, Yrlan; Giarrizzo, Tommaso; Vallinoto, Marcelo

    2015-01-01

    Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes. PMID:26630347

  11. Comparative Allometric Growth of the Mimetic Ephippid Reef Fishes Chaetodipterus faber and Platax orbicularis

    PubMed Central

    Barros, Breno; Sakai, Yoichi; Pereira, Pedro H. C.; Gasset, Eric; Buchet, Vincent; Maamaatuaiahutapu, Moana; Ready, Jonathan S.; Oliveira, Yrlan; Giarrizzo, Tommaso; Vallinoto, Marcelo

    2015-01-01

    Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes. PMID:26630347

  12. Regional scale spatio-temporal variability of soil moisture and its relationship with meteorological factors over the Korean peninsula

    NASA Astrophysics Data System (ADS)

    Cho, Eunsang; Choi, Minha

    2014-08-01

    An understanding soil moisture spatio-temporal variability is essential for hydrological and meteorological research. This work aims at evaluating the spatio-temporal variability of near surface soil moisture and assessing dominant meteorological factors that influence spatial variability over the Korean peninsula from May 1 to September 29, 2011. The results of Kolmogorov-Smirnov tests for goodness of fit showed that all applied distributions (normal, log-normal and generalized extreme value: GEV) were appropriate for the datasets and the GEV distribution described best spatial soil moisture patterns. The relationship between the standard deviation and coefficient of variation (CV) of soil moisture with mean soil moisture contents showed an upper convex shape and an exponentially negative pattern, respectively. Skewness exhibited a decreasing pattern with increasing mean soil moisture contents and kurtosis exhibited the U-shaped relationship. In this regional scale (99,720 km2), we found that precipitation indicated temporally stable features through an ANOVA test considering the meteorological (i.e. precipitation, insolation, air temperature, ground temperature and wind speed) and physical (i.e. soil texture, elevation, topography, and land use) factors. Spatial variability of soil moisture affected by the meteorological forcing is shown as result of the relationship between the meteorological factors (precipitation, insolation, air temperature and ground temperature) and the standard deviation of relative difference of soil moisture contents (SDRDt) which implied the spatial variability of soil moisture. The SDRDt showed a positive relationship with the daily mean precipitation, while a negative relationship with insolation, air temperature and ground temperature. The variation of spatial soil moisture pattern is more sensitive to change in ground temperature rather than air temperature changes. Therefore, spatial variability of soil moisture is greatly affected

  13. Relationship between isotope composition of sulphur in sulphate dissolved in river water and sulphur extracted from fish scales.

    PubMed

    Trembaczowski, Andrzej; Niezgoda, Halina

    2011-06-01

    More than 100 trouts captured in more than 20 rivers from Poland have been analysed. Only fish caught by trout fishermen were used for this study. Isotope compositions of sulphur (δ(34)S) and carbon (δ(13)C) of fish scales were examined together with δ(34)S from sulphate dissolved in river, as well as patterns of fish diet. We predominantly examined adult fish, at least 4 years old. A scatter of isotope values occurred among the samples obtained from fish caught in different rivers and also for fish caught in the same river. The scatter of the δ(34)S values was much larger than that of δ(13)C values. We noticed the relationship between δ(34)S of scales and δ(34)S of riverine sulphate. There is also a significant difference between isotope compositions obtained for different fish species, which can be attributed to their different diet. PMID:21644133

  14. Rape Myth Scale: factor structure and relationship with gender egalitarianism among Japanese professionals.

    PubMed

    Uji, Masayo; Shono, Masahiro; Shikai, Noriko; Kitamura, Toshinori

    2007-08-01

    Services provided to rape victims by human service professionals are usually helpful but are occasionally very harmful in that the victim ends up feeling 're-victimized'. This may be caused by the attitudes of the professionals towards the victims based on beliefs regarding rape and gender roles. Japanese human service professionals were solicited for responses to the Rape Myth Scale (RMS) and the short form of the Scale of Egalitarian Sex Role Attitudes (SESRA-S). One interpretable factor was extracted according to an exploratory factor analysis. Impact of the participants' age, sex, residential area, and type of profession on rape myth acceptance were examined by four-way layout ANOVA. Nurses had significantly higher rape myth acceptance than any other professional group. Furthermore, a structural equation model showing the contribution of sex role egalitarian attitude to rape myth acceptance was established. PMID:17610664

  15. The relationship between adience-abience scale scores and judged communication proficiency of alaryngeal speakers.

    PubMed

    Goldstein, L P; Salmon, S J

    1978-11-01

    Fifteen esophageal speakers and 15 artificial larynx speakers were administered the Hutt Adaptation of the Bender-Gestalt Test (HABGT): Adience-Abience Scale. Adience was defined as the individual's tendency to be motivated to adapt to new experiences that effect his physical functioning. Conversely, abience was defined as the individual's tendency to avoid or be inhibited from adapting to new experiences that effect his physical functioning. Audio-tape recordings were made of each speaker and used to determine verbal communication proficiency by six speech pathologists. Results indicated that the HABGT: Adience-Abience Scale was able to differentiate between the two groups of alaryngeal speakers, as well as relate to their verbal communication proficiency. PMID:713676

  16. Cities, traffic, and CO2: A multidecadal assessment of trends, drivers, and scaling relationships

    PubMed Central

    Gately, Conor K.; Hutyra, Lucy R.; Sue Wing, Ian

    2015-01-01

    Emissions of CO2 from road vehicles were 1.57 billion metric tons in 2012, accounting for 28% of US fossil fuel CO2 emissions, but the spatial distributions of these emissions are highly uncertain. We develop a new emissions inventory, the Database of Road Transportation Emissions (DARTE), which estimates CO2 emitted by US road transport at a resolution of 1 km annually for 1980–2012. DARTE reveals that urban areas are responsible for 80% of on-road emissions growth since 1980 and for 63% of total 2012 emissions. We observe nonlinearities between CO2 emissions and population density at broad spatial/temporal scales, with total on-road CO2 increasing nonlinearly with population density, rapidly up to 1,650 persons per square kilometer and slowly thereafter. Per capita emissions decline as density rises, but at markedly varying rates depending on existing densities. We make use of DARTE’s bottom-up construction to highlight the biases associated with the common practice of using population as a linear proxy for disaggregating national- or state-scale emissions. Comparing DARTE with existing downscaled inventories, we find biases of 100% or more in the spatial distribution of urban and rural emissions, largely driven by mismatches between inventory downscaling proxies and the actual spatial patterns of vehicle activity at urban scales. Given cities’ dual importance as sources of CO2 and an emerging nexus of climate mitigation initiatives, high-resolution estimates such as DARTE are critical both for accurately quantifying surface carbon fluxes and for verifying the effectiveness of emissions mitigation efforts at urban scales. PMID:25847992

  17. Scaling relationships between bed load volumes, transport distances, and stream power in steep mountain channels

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes M.; Turowski, Jens M.; Rickenmann, Dieter; Hegglin, Ramon; Arrigo, Sabrina; Mao, Luca; Kirchner, James W.

    2014-03-01

    Bed load transport during storm events is both an agent of geomorphic change and a significant natural hazard in mountain regions. Thus, predicting bed load transport is a central challenge in fluvial geomorphology and natural hazard risk assessment. Bed load transport during storm events depends on the width and depth of bed scour, as well as the transport distances of individual sediment grains. We traced individual gravels in two steep mountain streams, the Erlenbach (Switzerland) and Rio Cordon (Italy), using magnetic and radio frequency identification tags, and measured their bed load transport rates using calibrated geophone bed load sensors in the Erlenbach and a bed load trap in the Rio Cordon. Tracer transport distances and bed load volumes exhibited approximate power law scaling with both the peak stream power and the cumulative stream energy of individual hydrologic events. Bed load volumes scaled much more steeply with peak stream power and cumulative stream energy than tracer transport distances did, and bed load volumes scaled as roughly the third power of transport distances. These observations imply that large bed load transport events become large primarily by scouring the bed deeper and wider, and only secondarily by transporting the mobilized sediment farther. Using the sediment continuity equation, we can estimate the mean effective thickness of the actively transported layer, averaged over the entire channel width and the duration of individual flow events. This active layer thickness also followed approximate power law scaling with peak stream power and cumulative stream energy and ranged up to 0.57 m in the Erlenbach, broadly consistent with independent measurements.

  18. Note on the relationship between nude figure drawings and the MMPI scales.

    PubMed

    Brown, E L

    1982-08-01

    MMPI protocols of 40 asthmatic patients who produced nude DAPs were compared to a matched control group of equal number, Independent t tests computed for the validity and clinical scales of the MMPI between groups yielded not a single statistically significant difference. In contrast to the importance generally ascribed to global ratings of DAP figures, the global rating of nudity on DAP drawings did not differentiate any aspect of personality as measured by the MMPI. PMID:16370592

  19. Cities, traffic, and CO2: A multidecadal assessment of trends, drivers, and scaling relationships.

    PubMed

    Gately, Conor K; Hutyra, Lucy R; Sue Wing, Ian

    2015-04-21

    Emissions of CO2 from road vehicles were 1.57 billion metric tons in 2012, accounting for 28% of US fossil fuel CO2 emissions, but the spatial distributions of these emissions are highly uncertain. We develop a new emissions inventory, the Database of Road Transportation Emissions (DARTE), which estimates CO2 emitted by US road transport at a resolution of 1 km annually for 1980-2012. DARTE reveals that urban areas are responsible for 80% of on-road emissions growth since 1980 and for 63% of total 2012 emissions. We observe nonlinearities between CO2 emissions and population density at broad spatial/temporal scales, with total on-road CO2 increasing nonlinearly with population density, rapidly up to 1,650 persons per square kilometer and slowly thereafter. Per capita emissions decline as density rises, but at markedly varying rates depending on existing densities. We make use of DARTE's bottom-up construction to highlight the biases associated with the common practice of using population as a linear proxy for disaggregating national- or state-scale emissions. Comparing DARTE with existing downscaled inventories, we find biases of 100% or more in the spatial distribution of urban and rural emissions, largely driven by mismatches between inventory downscaling proxies and the actual spatial patterns of vehicle activity at urban scales. Given cities' dual importance as sources of CO2 and an emerging nexus of climate mitigation initiatives, high-resolution estimates such as DARTE are critical both for accurately quantifying surface carbon fluxes and for verifying the effectiveness of emissions mitigation efforts at urban scales. PMID:25847992

  20. Holocene multidecadal- to millennial-scale variations in Iceland-Scotland overflow and their relationship to climate

    NASA Astrophysics Data System (ADS)

    Mjell, Tor Lien; Ninnemann, Ulysses S.; Eldevik, Tor; Kleiven, Helga Kikki F.

    2015-05-01

    The Nordic Seas overflows are an important part of the Atlantic thermohaline circulation. While there is growing evidence that the overflow of dense water changed on orbital time scales during the Holocene, less is known about the variability on shorter time scales beyond the instrumental record. Here we reconstruct the relative changes in flow strength of Iceland-Scotland Overflow Water (ISOW), the eastern branch of the overflows, on multidecadal-millennial time scales. The reconstruction is based on mean sortable silt (SS>¯) from a sediment core on the Gardar Drift (60°19'N, 23°58'W, 2081 m). Our SS>¯ record reveals that the main variance in ISOW vigor occurred on millennial time scales (1-2 kyr) with particularly prominent fluctuations after 8 kyr. Superimposed on the millennial variability, there were multidecadal-centennial flow speed fluctuations during the early Holocene (10-9 kyr) and one prominent minimum at 0.9 kyr. We find a broad agreement between reconstructed ISOW and regional North Atlantic climate, where a strong (weak) ISOW is generally associated with warm (cold) climate. We further identify the possible contribution of anomalous heat and freshwater forcing, respectively, related to reconstructed overflow variability. We infer that ocean poleward heat transport can explain the relationship between regional climate and ISOW during the middle to late Holocene, whereas freshwater input provides a possible explanation for the reduced overflow during early Holocene (8-10 kyr).

  1. Structure–property relationships in atomic-scale junctions: Histograms and beyond

    DOE PAGESBeta

    Mark S. Hybertsen; Venkataraman, Latha

    2016-03-03

    Over the past 10 years, there has been tremendous progress in the measurement, modeling and understanding of structure–function relationships in single molecule junctions. Numerous research groups have addressed significant scientific questions, directed both to conductance phenomena at the single molecule level and to the fundamental chemistry that controls junction functionality. Many different functionalities have been demonstrated, including single-molecule diodes, optically and mechanically activated switches, and, significantly, physical phenomena with no classical analogues, such as those based on quantum interference effects. Experimental techniques for reliable and reproducible single molecule junction formation and characterization have led to this progress. In particular, themore » scanning tunneling microscope based break-junction (STM-BJ) technique has enabled rapid, sequential measurement of large numbers of nanoscale junctions allowing a statistical analysis to readily distinguish reproducible characteristics. Furthermore, harnessing fundamental link chemistry has provided the necessary chemical control over junction formation, enabling measurements that revealed clear relationships between molecular structure and conductance characteristics.« less

  2. Relationships among sediment chemistry, toxicity testing, and biology: What can large-scale monitoring teach us?

    SciTech Connect

    Summers, J.K.; Macauley, J.M.; Engle, V.D.; Malaeb, Z.

    1995-12-31

    The Environmental Monitoring and Assessment Program for Estuarine Resources has collected sediments from over 1,000 varying locations in the estuaries of the United States. At each of these sites, sediments are analyzed for bulk chemistry, tested for toxicity to Ampelisca abdita, and enumerated regarding benthic community structure and abundance. In addition, tissue residues have been examined for selected fish and shellfish species and toxicity testing has been completed at selected sites for alternative species. The statistical and ecological relationships among these indicators have been examined with regard to how they can used to identify the overall ecological condition of a site, an estuary, or populations of estuaries. Comparisons of these relationships among different regions of the country show major differences in the modes of exposure and response being prevalent in the Southeast and Gulf Coasts as compared to the Mid-Atlantic and West Coasts. While the extent of sediment contamination in the Southeast and Gulf estuaries appears to be similar to that of the Mid-Atlantic and California Coasts, the degree of contamination at contaminated sites is much greater in Mid-Atlantic estuaries. An examination of the primary contaminants suggests that the primary sources of contamination in the Mid-Atlantic are industrial and urban while the Southeast and Gulf estuaries are dominated by agricultural contaminants.

  3. The variability of winter high temperature extremes in Romania and its relationship with large-scale atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Rimbu, N.; Stefan, S.; Necula, C.

    2015-07-01

    The frequency variability of extreme high winter temperature as recorded at 85 meteorological stations from Romania during 1962-2010 period and its relationship with large-scale atmospheric circulation was investigated. An Empirical Orthogonal Function analysis reveals that large part of the extreme temperature frequency variability is common to all stations suggesting a strong influence of large-scale circulation anomalies. The North Atlantic Oscillation, West Pacific, East Atlantic, and Scandinavian patterns are related with extreme temperature frequency variability. We show that the East Atlantic Oscillation controls a significant part of interannual extreme high temperature variability over Romania via advection of warm air from the west. In addition, a strong relationship between blocking activity and frequency of extreme high temperature events in Romania was found. High blocking activity in the (20°W-70°E) sector is related with relatively strong advection of cold air over the country during winter. On the other hand, low blocking activity in the same sector is related with weak advection of relatively cold air in the region. Moreover, the blocking frequency in this sector is modulated mainly by the East Atlantic Oscillation.

  4. Relationship between Pulsating Aurora and Small-scale Field-Aligned Current Systems

    NASA Astrophysics Data System (ADS)

    Gillies, D. M.; Knudsen, D. J.; Donovan, E.; Kabirzadeh, R.

    2014-12-01

    Field-aligned currents derived from CHAMP satellite overpasses were compared to THEMIS ground-based all-sky camera array. Two separate conjunctions were studied in detail. The primary focus of this study was to investigate FAC derived from magnetometer measurements obtained by CHAMP collocated with various auroral phenomena. Two types of aurora were studied in detail: pulsating aurora and diffuse aurora occurring equatorward ward of an established auroral arc. We found that pulsating aurora exhibited low levels of fluctuating field aligned currents alternating between +/- 1 μA/m2 for the duration of the conjunction. We found similar behaviour for diffuse aurora equatorward of stable auroral arc events. Upon entering the region of diffuse aurora CHAMP recorded an alternating current fluctuating between +/- 5 μA/m2. High resolution data confirmed this alternating current structure as well as the presence of small scale arc structure seen by larger, small time scale amplitude fluctuations similar to that seen in the auroral arcs. These results show that electrical currents in diffuse and pulsating auroral structures are relevant.

  5. Millimeter-scale epileptiform spike propagation patterns and their relationship to seizures

    NASA Astrophysics Data System (ADS)

    Vanleer, Ann C.; Blanco, Justin A.; Wagenaar, Joost B.; Viventi, Jonathan; Contreras, Diego; Litt, Brian

    2016-04-01

    Objective. Current mapping of epileptic networks in patients prior to epilepsy surgery utilizes electrode arrays with sparse spatial sampling (∼1.0 cm inter-electrode spacing). Recent research demonstrates that sub-millimeter, cortical-column-scale domains have a role in seizure generation that may be clinically significant. We use high-resolution, active, flexible surface electrode arrays with 500 μm inter-electrode spacing to explore epileptiform local field potential (LFP) spike propagation patterns in two dimensions recorded from subdural micro-electrocorticographic signals in vivo in cat. In this study, we aimed to develop methods to quantitatively characterize the spatiotemporal dynamics of epileptiform activity at high-resolution. Approach. We topically administered a GABA-antagonist, picrotoxin, to induce acute neocortical epileptiform activity leading up to discrete electrographic seizures. We extracted features from LFP spikes to characterize spatiotemporal patterns in these events. We then tested the hypothesis that two-dimensional spike patterns during seizures were different from those between seizures. Main results. We showed that spatially correlated events can be used to distinguish ictal versus interictal spikes. Significance. We conclude that sub-millimeter-scale spatiotemporal spike patterns reveal network dynamics that are invisible to standard clinical recordings and contain information related to seizure-state.

  6. Millimeter-scale epileptiform spike propagation patterns and their relationship to seizures

    PubMed Central

    Vanleer, Ann C; Blanco, Justin A; Wagenaar, Joost B; Viventi, Jonathan; Contreras, Diego; Litt, Brian

    2016-01-01

    Objective Current mapping of epileptic networks in patients prior to epilepsy surgery utilizes electrode arrays with sparse spatial sampling (∼1.0 cm inter-electrode spacing). Recent research demonstrates that sub-millimeter, cortical-column-scale domains have a role in seizure generation that may be clinically significant. We use high-resolution, active, flexible surface electrode arrays with 500 μm inter-electrode spacing to explore epileptiform local field potential spike propagation patterns in two dimensions recorded from subdural micro-electrocorticographic signals in vivo in cat. In this study, we aimed to develop methods to quantitatively characterize the spatiotemporal dynamics of epileptiform activity at high-resolution. Approach We topically administered a GABA-antagonist, picrotoxin, to induce acute neocortical epileptiform activity leading up to discrete electrographic seizures. We extracted features from local field potential spikes to characterize spatiotemporal patterns in these events. We then tested the hypothesis that two dimensional spike patterns during seizures were different from those between seizures. Main results We showed that spatially correlated events can be used to distinguish ictal versus interictal spikes. Significance We conclude that sub-millimeter-scale spatiotemporal spike patterns reveal network dynamics that are invisible to standard clinical recordings and contain information related to seizure-state. PMID:26859260

  7. Relationships of sedimentation and benthic macroinvertebrate assemblages in headwater streams using systematic longitudinal sampling at the reach scale.

    PubMed

    Longing, S D; Voshell, J R; Dolloff, C A; Roghair, C N

    2010-02-01

    Investigating relationships of benthic invertebrates and sedimentation is challenging because fine sediments act as both natural habitat and potential pollutant at excessive levels. Determining benthic invertebrate sensitivity to sedimentation in forested headwater streams comprised of extreme spatial heterogeneity is even more challenging, especially when associated with a background of historical and intense watershed disturbances that contributed unknown amounts of fine sediments to stream channels. This scenario exists in the Chattahoochee National Forest where such historical timber harvests and contemporary land-uses associated with recreation have potentially affected the biological integrity of headwater streams. In this study, we investigated relationships of sedimentation and the macroinvertebrate assemblages among 14 headwater streams in the forest by assigning 30, 100-m reaches to low, medium, or high sedimentation categories. Only one of 17 assemblage metrics (percent clingers) varied significantly across these categories. This finding has important implications for biological assessments by showing streams impaired physically by sedimentation may not be impaired biologically, at least using traditional approaches. A subsequent multivariate cluster analysis and indicator species analysis were used to further investigate biological patterns independent of sedimentation categories. Evaluating the distribution of sedimentation categories among biological reach clusters showed both within-stream variability in reach-scale sedimentation and sedimentation categories generally variable within clusters, reflecting the overall physical heterogeneity of these headwater environments. Furthermore, relationships of individual sedimentation variables and metrics across the biological cluster groups were weak, suggesting these measures of sedimentation are poor predictors of macroinvertebrate assemblage structure when using a systematic longitudinal sampling design

  8. Fish foraging patterns, vulnerability to fishing, and implications for the management of ecosystem function across scales.

    PubMed

    Nash, Kirsty L; Graham, Nicholas A J; Bellwood, David R

    2013-10-01

    The function of species has been recognized as critical for the maintenance of ecosystems within desired states. However, there are still considerable gaps in our knowledge of interspecific differences in the functional roles of organisms, particularly with regard to the spatial scales over which functional impact is exerted. This has implications for the delivery of function and the maintenance of ecosystem processes. In this study we assessed the allometric relationship between foraging movements and fish body length at three sites, for 20 species of herbivorous reef fishes within four different functional groups: browsers, farmers, grazer/ detritivores, and scraper/excavators. The relationship between vulnerability of species to fishing and their scale of foraging was also examined. We present empirical evidence of the strong, positive, log-linear relationship between the scale of foraging movement and fish body length. This relationship was consistent among sites and between the two different movement metrics used. Phylogeny did not affect these results. Functional groups foraged over contrasting ranges of spatial scales; for example, scraper/excavators performed their role over a wide range of scales, whereas browsers were represented by few species and operated over a narrow range of scales. Overfishing is likely not only to remove species operating at large scales, but also to remove the browser group as a whole. Large fishes typically have a significant role in removing algae on reefs, and browsers are key to controlling macroalgae and reversing shifts to macroalgal-dominated states. This vulnerability to exploitation has serious consequences for the ability of fish assemblages to deliver their functional role in the face of anthropogenic impacts. However, identification of the scales at which herbivorous fish assemblages are susceptible to fishing provides managers with critical knowledge to design management strategies to support coral-dominated reefs by

  9. Ontogenetic changes in the scaling of cellular respiration with respect to size among sunflower seedlings.

    PubMed

    Kutschera, U; Niklas, K J

    2011-01-01

    The respiration rates R (oxygen uptake per min) and body mass M (mg per individual) of sunflower (Helianthus annuus L.) seedlings were measured for populations raised in the dark (scotomorphogenesis) and for plants subsequently grown in white light (photomorphogenesis) to determine the allometric (scaling) relationship for R vs. M. Based on ordinary least squares and reduced major axis regression protocols, cellular respiration rates were found to increase non-linearly as a 'broken-stick' curve of increasing M. During germination, the scaling was ca. 7.5-fold higher than after the emergence of the cotyledons from the seed coat, which can be attributed to the hypoxic conditions of the enclosed embryo. During seedling development, R was found to scale roughly as the 3/7 power of body mass (i.e., R ~ M(-3/7)), regardless of whether plants were grown in the dark or subsequently in white light. The numerical value of 3/7 statistically significantly differs from that reported across field- or laboratory-grown plants (i.e., R ~ M(-1.0)). It also differs from the expectations of recent allometric theory (i.e., R ~ M(-0.75) to M(-1.0)). This difference is interpreted to be the result of species-specific tissue-compositions that affect the volume fractions of metabolically active and less active cells. These findings, which are supported by cytological and ultrastructural observations (i.e., scanning- and transmission electron micrographs), draw attention to the need to measure R of developing plants in a tissue- or organ-specific context. PMID:21301213

  10. Effect of bedrock permeability on stream base flow mean transit time scaling relationships: 2. Process study of storage and release

    NASA Astrophysics Data System (ADS)

    Hale, V. Cody; McDonnell, Jeffrey J.; Stewart, Michael K.; Solomon, D. Kip; Doolitte, Jim; Ice, George G.; Pack, Robert T.

    2016-02-01

    In Part 1 of this two-part series, Hale and McDonnell (2016) showed that bedrock permeability controlled base flow mean transit times (MTTs) and MTT scaling relations across two different catchment geologies in western Oregon. This paper presents a process-based investigation of storage and release in the more permeable catchments to explain the longer MTTs and (catchment) area-dependent scaling. Our field-based study includes hydrometric, MTT, and groundwater dating to better understand the role of subsurface catchment storage in setting base flow MTTs. We show that base flow MTTs were controlled by a mixture of water from discrete storage zones: (1) soil, (2) shallow hillslope bedrock, (3) deep hillslope bedrock, (4) surficial alluvial plain, and (5) suballuvial bedrock. We hypothesize that the relative contributions from each component change with catchment area. Our results indicate that the positive MTT-area scaling relationship observed in Part 1 is a result of older, longer flow path water from the suballuvial zone becoming a larger proportion of streamflow in a downstream direction (i.e., with increasing catchment area). Our work suggests that the subsurface permeability structure represents the most basic control on how subsurface water is stored and therefore is perhaps the best direct predictor of base flow MTT (i.e., better than previously derived morphometric-based predictors). Our discrete storage zone concept is a process explanation for the observed scaling behavior of Hale and McDonnell (2016), thereby linking patterns and processes at scales from 0.1 to 100 km2.

  11. Scale effect analysis of the relationships between urban heat island and impact factors: case study in Chongqing

    NASA Astrophysics Data System (ADS)

    Luo, Xiaobo; Li, Weisheng

    2014-01-01

    Several indices, including the normalized difference vegetation index (NDVI), normalized difference build-up index (NDBI), and normalized difference water index (NDWI), were retrieved from the Landsat 5 Thematic Mapper (TM) images, and the land surface temperature (LST) was reversed by the thermal radiation transfer model. Next, with the help of the thermal field variance index from LST, characteristics of spatial distribution of urban heat island were analyzed. Then, the regression models between LST and the three indices were formed by the least-squares method after they were aggregated from 30 to 120, 240, 480, 960, and 1200 m, and the relationships between the accuracies of the regression models and spatial scales were analyzed quantitatively. Finally, results from the experiment exemplified by Chongqing show that at all these spatial scales, both NDVI and NDWI are negatively correlated with LST and NDBI is positively correlated with LST. At the same spatial scale, cooling effect by NDWI acting upon LST is superior to that by NDVI, while inferior to that by NDBI to enhance LST. The fitting determination coefficients (R) of the regression models of LST and NDVI, NDBI, and NDWI increase from 0.23 (30 m) to 0.57 (1200 m), from 0.34 (30 m) to 0.70 (1200 m), and from 0.31 (30 m) to 0.68 (1200 m), respectively. Further, the R of all of the regression models and spatial scales have positive logarithmic function relations, while the standard deviation and spatial scale have negative logarithmic function relations correspondingly, and the R of all of the logarithmic models are >0.95. The heat islands of Chongqing are roughly along northeast-southwest directions, while the heat islands of the urban core area, such as Yuzhong district, are not obvious due to the influence of the Yangtze River and the Jialing River.

  12. Defining the Relationship between Seismicity and Deformation at Regional and Local Scales

    NASA Astrophysics Data System (ADS)

    Williams, Nneka Njeri Akosua

    In this thesis, I use source inversion methods to improve understanding of crustal deformation along the Nyainquentanglha (NQTL) Detachment in Southern Tibet and the Piceance Basin in northwestern Colorado. Broadband station coverage in both regions is sparse, necessitating the development of innovative approaches to source inversion for the purpose of studying local earthquakes. In an effort to study the 2002-2003 earthquake swarm and the 2008 M w 6.3 Damxung earthquake and aftershocks that occurred in the NQTL region, we developed a single station earthquake location inversion method called the SP Envelope method, to be used with data from LHSA at Lhasa, a broadband seismometer located 75 km away. A location is calculated by first rotating the seismogram until the azimuth at which the envelope of the P-wave arrival on the T-component is smallest (its great circle path) is found. The distance at which to place the location along this azimuth is measured by calculating the S-P distance from arrivals on the seismogram. When used in conjunction with an existing waveform modeling based source inversion method called Cut and Paste (CAP), a catalog of 40 regional earthquakes was generated. From these 40 earthquakes, a catalog of 30 earthquakes with the most certain locations was generated to study the relationship of seismicity and NQTL region faults mapped in Google Earth™ and in Armijo et al., 1986 and Kapp et al., 2005. Using these faults and focal mechanisms, a fault model of the NQTL Region was generated using GOCAD, a 3D modeling suite. By studying the relationship of modeled faults to mapped fault traces at the surface, the most likely fault slip plane was chosen. These fault planes were then used to calculate slip vectors and a regional bulk stress tensor, with respect to which the low-angle NQTL Detachment was found to be badly misoriented. The formation of low-angle normal faults is inconsistent with the Anderson Theory of faulting, and the presence of the

  13. Toward new institutional relationships in the development of small scale hydroelectric power

    SciTech Connect

    Brown, P.W.

    1980-12-01

    This paper will briefly discuss three principle subjects. These subjects are recent changes in hydroelectric licensing, provisions of the Public Utility Regulatory Policies Act of 1978 (PURPA) and the regulations promulgated pursuant to the Act by the Federal Energy Regulatory Commission (FERC) and Sections 221 and 222 (e), and Section 242 of the Crude Oil Windfall Profit Tax Act of 1980. The FERC has recently reformed its licensing and permit regulations and Congress has enacted Section 408 of the Energy Security Act to exempt certain projects from the FERC licensing. PURPA and the FERC regulations promulgated pursuant thereto guarantee markets for the output of small scale hydroelectric (SSH) plants and the provisions of the Windfall Profit Tax Act measurably assist in the raising of capital for the construction of SSH facilities. All three incentives are significant given the electric utility markets confronted by SSH developers and the capital intensive nature of SSH projects.

  14. Fine scale relationships between sex, life history, and dispersal of masu salmon

    USGS Publications Warehouse

    Kitanishi, Shigeru; Yamamoto, Toshiaki; Koizumi, Itsuro; Dunham, Jason B.; Higashi, Seigo

    2012-01-01

    Identifying the patterns and processes driving dispersal is critical for understanding population structure and dynamics. In many organisms, sex-biased dispersal is related to the type of mating system. Considerably less is known about the influence of life history variability on dispersal. Here we investigated patterns of dispersal in masu salmon (Oncorhynchus masou) to evaluate influences of sex and life history on dispersal. As expected, assignment tests and isolation by distance analysis revealed that dispersal of marine-migratory masu salmon was male-biased. However, dispersal of resident and migratory males did not follow our expectation and marine-migratory individuals dispersed more than residents. This may be because direct competition between marine-migratory and resident males is weak or that the cost of dispersal is smaller for marine-migratory individuals. This study revealed that both sex and migratory life history influence patterns of dispersal at a local scale in masu salmon.

  15. Quantity-activity relationship of denitrifying bacteria and environmental scaling in streams of a forested watershed

    NASA Astrophysics Data System (ADS)

    O'Connor, Ben L.; Hondzo, Miki; Dobraca, Dina; Lapara, Timothy M.; Finlay, Jacques C.; Brezonik, Patrick L.

    2006-12-01

    The spatial variability of subreach denitrification rates in streams was evaluated with respect to controlling environmental conditions, molecular examination of denitrifying bacteria, and dimensional analysis. Denitrification activities ranged from 0 and 800 ng-N gsed-1 d-1 with large variations observed within short distances (<50 m) along stream reaches. A log-normal probability distribution described the range in denitrification activities and was used to define low (16% of the probability distribution), medium (68%), and high (16%) denitrification potential groups. Denitrifying bacteria were quantified using a competitive polymerase chain reaction (cPCR) technique that amplified the nirK gene that encodes for nitrite reductase. Results showed a range of nirK quantities from 103 to 107 gene-copy-number gsed-1. A nonparametric statistical test showed no significant difference in nirK quantities among stream reaches, but revealed that samples with a high denitrification potential had significantly higher nirK quantities. Denitrification activity was positively correlated with nirK quantities with scatter in the data that can be attributed to varying environmental conditions along stream reaches. Dimensional analysis was used to evaluate denitrification activities according to environmental variables that describe fluid-flow properties, nitrate and organic material quantities, and dissolved oxygen flux. Buckingham's pi theorem was used to generate dimensionless groupings and field data were used to determine scaling parameters. The resulting expressions between dimensionless NO3- flux and dimensionless groupings of environmental variables showed consistent scaling, which indicates that the subreach variability in denitrification rates can be predicted by the controlling physical, chemical, and microbiological conditions.

  16. Quantity-activity relationship of denitrifying bacteria and environmental scaling in streams of a forested watershed

    USGS Publications Warehouse

    O'Connor, B.L.; Hondzo, Miki; Dobraca, D.; LaPara, T.M.; Finlay, J.A.; Brezonik, P.L.

    2006-01-01

    The spatial variability of subreach denitrification rates in streams was evaluated with respect to controlling environmental conditions, molecular examination of denitrifying bacteria, and dimensional analysis. Denitrification activities ranged from 0 and 800 ng-N gsed-1 d-1 with large variations observed within short distances (<50 m) along stream reaches. A log-normal probability distribution described the range in denitrification activities and was used to define low (16% of the probability distributibn), medium (68%), and high (16%) denitrification potential groups. Denitrifying bacteria were quantified using a competitive polymerase chain reaction (cPCR) technique that amplified the nirK gene that encodes for nitrite reductase. Results showed a range of nirK quantities from 103 to 107 gene-copy-number gsed.-1 A nonparametric statistical test showed no significant difference in nirK quantifies among stream reaches, but revealed that samples with a high denitrification potential had significantly higher nirK quantities. Denitrification activity was positively correlated with nirK quantities with scatter in the data that can be attributed to varying environmental conditions along stream reaches. Dimensional analysis was used to evaluate denitrification activities according to environmental variables that describe fluid-flow properties, nitrate and organic material quantities, and dissolved oxygen flux. Buckingham's pi theorem was used to generate dimensionless groupings and field data were used to determine scaling parameters. The resulting expressions between dimensionless NO3- flux and dimensionless groupings of environmental variables showed consistent scaling, which indicates that the subreach variability in denitrification rates can be predicted by the controlling physical, chemical, and microbiological conditions. Copyright 2006 by the American Geophysical Union.

  17. Percolating transport and the conductive scaling relationship in lamellar block copolymers under confinement.

    PubMed

    Diederichsen, Kyle M; Brow, Ryan R; Stoykovich, Mark P

    2015-03-24

    The topology and transport behavior of the lamellar morphology self-assembled by block copolymers in thin films are shown to depend on the length scale over which they are characterized and can be described by percolation in a network under confinement. Gold nanowires replicating the lamellar morphology were fabricated via self-assembled poly(styrene-block-methyl methacrylate) thin films and a lift-off pattern transfer process. The lamellar morphology exhibits long-range connectivity (macroscopic scale); however, characterization of electrical conduction over confined areas (5-500 μm) demonstrates a discrete probability of disconnection that arises due to the underlying network structure and a lack of self-similarity at these microscale dimensions. In particular, it is proved that the lamellar network morphology under confinement has a conductance that is nonlinear with channel length or width. The experimental results are discussed in terms of percolation theory, and a simple, two-dimensional Monte Carlo model is shown to predict the key trends in the network topology and conductance in lamellar block copolymers, including the dependencies on composition, extent of spatial confinement, and confinement geometry. These results highlight the need to exquisitely control or engineer the self-assembled nanostructured pathways formed by block copolymers to ensure consistent device performance for any application that depends upon percolating material, ionic, or electrical transport, especially when confined in any dimension. It is also concluded that the two most promising approaches for enhancing conductivity in block copolymer materials may be achieved either at the limits of (1) perfectly oriented, single-crystalline or (2) high defect density, polycrystalline microphase separated morphologies and that nanostructured systems with intermediate defect densities would be detrimental to transport in confined systems. PMID:25756653

  18. [Biomass allometric equations of nine common tree species in an evergreen broadleaved forest of subtropical China].

    PubMed

    Zuo, Shu-di; Ren, Yin; Weng, Xian; Ding, Hong-feng; Luo, Yun-jian

    2015-02-01

    Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the species-specific and generalized BAEs using biomass measurement for 9 common broadleaved trees (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in species-specific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total tree than a combined variable (D2 H) of D and H (tree height) , but D2H was better than D in estimating stem biomass. R2 (coefficient of determination) values of BAEs for 6 species decreased when adding H as the second independent variable into D- only BAEs, where R2 value for S. sinensis decreased by 5.6%. Compared with generalized D- and D2H-based BAEs, standard errors of estimate (SEE) of BAEs for 8 tree species decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by tree species and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in tree species and model types. PMID:26094447

  19. Size matters: insights from an allometric approach to evaluate control methods for invasive Australian Rhinella marina.

    PubMed

    Beaty, Lynne E; Salice, Christopher J

    2013-10-01

    Invasive species are costly and difficult to control. In order to gain a mechanistic understanding of potential control measures, individual-based models uniquely parameterized to reflect the salient life-history characteristics of invasive species are useful. Using invasive Australian Rhinella marina as a case study, we constructed a cohort- and individual-based population simulation that incorporates growth and body size of terrestrial stages. We used this allometric approach to examine the efficacy of nontraditional control methods (i.e., tadpole alarm chemicals and native meat ants) that may have indirect effects on population dynamics mediated by effects on body size. We compared population estimates resulting from these control methods with traditional hand removal. We also conducted a sensitivity analysis to investigate the effect that model parameters, specifically those associated with growth and body size, had on adult population estimates. Incremental increases in hand removal of adults and juveniles caused nonlinear decreases in adult population estimates, suggesting less return with increased investment in hand-removal efforts. Applying tadpole alarm chemicals or meat ants decreased adult population estimates on the same level as removing 15-25% of adults and juveniles by hand. The combined application of tadpole alarm chemicals and meat ants resulted in approximately 80% decrease in adult abundance, the largest of any applied control method. In further support of the nontraditional control methods, which greatly affected the metamorph stage, our model was most sensitive to changes in metamorph survival, juvenile survival, metamorph growth rate, and adult survival. Our results highlight the use and insights that can be gained from individual-based models that incorporate growth and body size and the potential success that nontraditional control methods could have in controlling established, invasive Rhinella marina populations. PMID:24261039

  20. Using Combined Morphological, Allometric and Molecular Approaches to Identify Species of the Genus Raillietiella (Pentastomida)

    PubMed Central

    Kelehear, Crystal; Spratt, David M.; Dubey, Sylvain; Brown, Gregory P.; Shine, Richard

    2011-01-01

    Taxonomic studies of parasites can be severely compromised if the host species affects parasite morphology; an uncritical analysis might recognize multiple taxa simply because of phenotypically plastic responses of parasite morphology to host physiology. Pentastomids of the genus Raillietiella are endoparasitic crustaceans primarily infecting the respiratory system of carnivorous reptiles, but also recorded from bufonid anurans. The delineation of pentastomids at the generic level is clear, but the taxonomic status of many species is not. We collected raillietiellids from lungs of the invasive cane toad (Rhinella marina), the invasive Asian house gecko (Hemidactylus frenatus), and a native tree frog (Litoria caerulea) in tropical Australia, and employed a combination of genetic analyses, and traditional and novel morphological methods to clarify their identity. Conventional analyses of parasite morphology (which focus on raw values of morphological traits) revealed two discrete clusters in terms of pentastome hook size, implying two different species of pentastomes: one from toads and a tree frog (Raillietiella indica) and another from lizards (Raillietiella frenatus). However, these clusters disappeared in allometric analyses that took pentastome body size into account, suggesting that only a single pentastome taxon may be involved. Our molecular data revealed no genetic differences between parasites in toads versus lizards, confirming that there was only one species: R. frenatus. This pentastome (previously known only from lizards) clearly is also capable of maturing in anurans. Our analyses show that the morphological features used in pentastomid taxonomy change as the parasite transitions through developmental stages in the definitive host. To facilitate valid descriptions of new species of pentastomes, future taxonomic work should include both morphological measurements (incorporating quantitative measures of body size and hook bluntness) and molecular data

  1. Effect of citalopram treatment on relationship between platelet serotonin functions and the Karolinska scales of personality in panic patients.

    PubMed

    Neuger, Jolanta; Wistedt, Börje; Aberg-Wistedt, Anna; Stain-Malmgren, Rigmor

    2002-08-01

    Using the Karolinska Scales of Personality (KSP), we investigated the effect of the selective serotonin reuptake inhibitor citalopram on personality traits and the relationship between personality traits and peripheral indexes for central serotonergic function in patients with panic disorder at baseline and after 6 months of treatment. The degree of anxiety and depression was assessed using the Beck Anxiety Inventory, the Beck Depression Inventory, the Clinical Anxiety Scale, and the Montgomery Asberg Depression Rating Scale. A reduction in anxiety and depression scores of 75% was observed after treatment in two thirds of the patients. Mean changes of 12% in the direction of normalization were observed in all KSP anxiety-related items (Somatic Anxiety, Muscular Tension, Psychic Anxiety, and Psychasthenia), the aggression and hostility related items (Inhibition of Aggression, Irritability, and Guilt) and the item of Socialisation. A positive correlation was found between Vmax for the platelet [14C]-serotonin uptake and Inhibition of Aggression before treatment, and a negative correlation was found between the affinity of serotonin uptake and Inhibition of Aggression after treatment. Negative childhood experiences influenced enhanced scores on some KSP items but not the serotonergic function. In panic patients treated with citalopram, effects were seen on personality traits, confirming an association between serotonergic activity and aggression. PMID:12172340

  2. A study of the relationship between permeability distributions and small scale sedimentary features in a fluvial formation

    SciTech Connect

    Gotkowitz, M.

    1993-10-01

    This study focuses on styles of small-scale heterogeneity found in fluvial sand and soil bodies. Over 1,700 in situ measurements of air permeability were taken in an outcrop-based study which joins observations of sedimentary features with their associated permeability distributions. The relationship between sedimentology and hydrologic parameters provides a geologic framework to assess geostatistical hypotheses. The soils in the study area are found to have a significantly lower permeability than the channel sand deposits. The soil deposits showed a significant lack of observable small scale sedimentary structures, which is reflected in the experimental variograms. The permeability distribution in these study sites appears to be adequately represented by a continuous gaussian random field model. The presence of calcium carbonate nodules in the soils is related to the permeability distribution. Correlation lengths in the channel sands perpendicular to stratigraphy are significantly shorter than those observed parallel to stratigraphy. A sedimentological, bounding surfaces model is evaluated with regard to permeability distributions. In deposits of little sedimentary structure, the mean and variance may adequately characterize the permeability distribution. Where significant sedimentary structure exists, the bounding surfaces model can be used to determine the scales of variability present in the permeability distribution and may also be used to infer an appropriate choice of random field model.

  3. [Relationship between hope and subjective well-being: reliability and validity of the dispositional Hope Scale, Japanese version].

    PubMed

    Kato, Tsukasa; Snyder, C R

    2005-08-01

    We conducted three studies to translate the Snyder Hope Sales into Japanese, examine reliability and validity of the Japanese version, and investigate the relationship between the tendency to be hopeful and subjective well-being. In Study 1, confirmatory factor analysis was performed of the Hope Scale in the Japanese version: agency and pathways. Its test-retest reliability coefficients for the data from 113 undergraduates ranged from .81 to .84. In Study 2, concurrent validity of the Japanese version Hope Scale was examined with the data from 550 respondents, which looked at the correlations between hope and optimism, self-esteem, and self-efficacy. Results suggested that the Japanese version had high validity. In addition, the tendency to be hopeful had negative correlations with stress response, hopelessness, depressive tendency, and trait anxiety, and positive one with feeling of happiness. In Study 3, 175 undergraduates completed the Hope Scale and State-Trait Anxiety Inventory (STAI) immediately prior to final examinations. Results of regression analysis suggested that the tendency to be hopeful moderated examination anxiety. Taken together, results of the studies supported the hypothesis that hope had positive effects on subjective well-being. PMID:16200877

  4. Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

    PubMed Central

    Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

    2014-01-01

    Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, P<0.01). Conclusions/Significance Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

  5. Conductivity Scaling Relationships in Nanostructured Membranes based on Protic Polymerized Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Sanoja, Gabriel; Lynd, Nathaniel; Segalman, Rachel

    2015-03-01

    Nanostructured membranes based on protic polymerized ionic liquids are of great interest for a variety of electrochemical applications. Understanding the relationship between composition, structure, and ionic conductivity for these materials is essential for designing novel membranes with improved properties. In this work, we explore the effect of volume fraction of ionic liquid on conductivity, σ using a model system composed of poly[isoprene-block-(ethylene oxide-stat-histamine glycidyl ether) diblock copolymers [PI- b - P(EO-stat-HGE)] and the resulting [PI- b - P(EO-stat-IL)] obtained after treatment with trifluoroacetic acid. These materials self-assemble into lamellar structures with volume fractions of ionic liquid ranging from 0.50 to 0.90 as demonstrated by SAXS. PI- b - P(EO-stat-IL) membranes exhibit conductivities up to 4 x 10-3 S/cm at room temperature. In addition, PI- b - P(EO-stat-IL) based membranes have lower water uptake (λ = 8-10) in comparison with most proton conducting membranes reported elsewhere. The low λ in these membranes might translate into a stronger effect of morphology on transport properties. Joint Center for Artificial Photosynthesis.

  6. How diversification rates and diversity limits combine to create large-scale species–area relationships

    PubMed Central

    Kisel, Yael; McInnes, Lynsey; Toomey, Nicola H.; Orme, C. David L.

    2011-01-01

    Species–area relationships (SARs) have mostly been treated from an ecological perspective, focusing on immigration, local extinction and resource-based limits to species coexistence. However, a full understanding across large regions is impossible without also considering speciation and global extinction. Rates of both speciation and extinction are known to be strongly affected by area and thus should contribute to spatial patterns of diversity. Here, we explore how variation in diversification rates and ecologically mediated diversity limits among regions of different sizes can result in the formation of SARs. We explain how this area-related variation in diversification can be caused by either the direct effects of area or the effects of factors that are highly correlated with area, such as habitat diversity and population size. We also review environmental, clade-specific and historical factors that affect diversification and diversity limits but are not highly correlated with region area, and thus are likely to cause scatter in observed SARs. We present new analyses using data on the distributions, ages and traits of mammalian species to illustrate these mechanisms; in doing so we provide an integrated perspective on the evolutionary processes shaping SARs. PMID:21807732

  7. The Relationship between the Kaufman Brief Intelligence Test and the Wechsler Intelligence Scale for Children-III in a Clinical Sample.

    ERIC Educational Resources Information Center

    Javorsky, James

    1993-01-01

    This study found a significant relationship between the Kaufman Brief Intelligence Test (K-BIT) and the Wechsler Intelligence Scale for Children-III (WISC-III) in 63 youth at a psychiatric hospital. A multiple regression equation was derived to provide an estimate of the WISC-III Full Scale Intelligence Quotient using the composites of the K-BIT.…

  8. Estimation of Regional-Scale Actual Evapotranspiration in Okayama prefecture in Japan using Complementary Relationship

    NASA Astrophysics Data System (ADS)

    Moroizumi, T.; Yamamoto, M.; Miura, T.

    2008-12-01

    It is important to estimate accurately a water balance in watershed for proposing a reuse of water resources and a proper settlement of water utilization. Evapotranspiration (ET) is an important factor of water balance. Therefore, it is needed to estimate accurately the actual ET. The objective of this study is to estimate accurately monthly actual ET in Yoshii, Asahi, and Takahashi River watersheds in Okayama prefecture from 1999 to 2000. The monthly actual ET was calculated by a Morton and a modified Brutsaert and Stricker (B&S) method, using Automated Meteorological Data Acquisition Systems (AMeDAS) in the basin. The actual ET was estimated using land covers which were classified in 11 categories. The land covers includes the effects of albedo. The actual ET was related to the elevation at each AMeDAS station. Using this relationship, the actual ET at the 1 or 5 km grid-interval mesh in the basin was calculated, and finally, the distribution of actual ET was mapped. The monthly ET estimated by the modified B&S method were smaller than that by Morton method which showed a same tendency as the Penman potential ET (PET). The annual values of Morton"fs ET, modified B&S"fs ET, and PET were estimated as 796, 645, and 800 mm, respectively. The ET by the modified B&S was larger in hilly and mountainous areas than in settlement or city. In general, it was a reasonable result because city or settlement areas were covered with concrete and asphalt and the ET was controlled.

  9. The relationship between religiosity and cardiovascular risk factors in Japan: a large-scale cohort study.

    PubMed

    Kobayashi, Daiki; Shimbo, Takuro; Takahashi, Osamu; Davis, Roger B; Wee, Christina C

    2015-07-01

    The goal of this study was to examine the relationship between religiosity and cardiovascular risk factors in a Japanese population. A retrospective cohort study was conducted involving individuals who underwent annual health check-ups at St. Luke's International Hospital from 2005 to 2010. Data collected included self-reported demographics, clinical information, and health habits, as well as religiosity, baseline examination, and laboratory measures. We conducted multivariable regression analyses to examine the associations between religiosity and cardiovascular risk factors at baseline and longitudinally. The analyses were performed in 2012. A total of 36,965 participants were enrolled, and 13,846 (37.8%) reported being at least somewhat religious. Compared with those who were not religious at baseline, religious participants (n = 3685) were less likely to be current smokers (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.53-0.67) and to report excessive alcohol consumption (OR, 0.74; 95% CI, 0.67-0.82), and more likely to exercise at least three times a week (OR, 1.27; 95% CI,1.16-1.39) and to be obese (OR, 1.32; 95% CI, 1.19-1.47). There were no significant differences in the rate of hypertension, diabetes mellitus, or dyslipidemia prevalence. In longitudinal data analyses, religiosity was associated with a lower likelihood of smoking and excessive alcohol consumption, and a higher likelihood of regular exercise and a lower incidence of diabetes over time. Individuals who were more religious were significantly more likely to have favorable health habits and fewer cardiovascular risk factors, except for a higher prevalence of overweight/obesity at baseline. Religiosity was also associated with better health habits over time and less likely to be associated with future diabetes but not with blood pressure or lipid levels. PMID:26188400

  10. Examining the relationship between flooding and large-scale climate indices over the central United States

    NASA Astrophysics Data System (ADS)

    Mallakpour, I.; Villarini, G.

    2015-12-01

    This study examines the climatic driving forces responsible for the observed changes in flood frequency over the central United States (North Dakota, South Dakota, Nebraska, Kansas, Missouri, Iowa, Minnesota, Wisconsin, Illinois, West Virginia, Kentucky, Ohio, Indiana, and Michigan). Results are based on daily streamflow records from 774 U.S. Geological Survey (USGS) stations with a record of at least 50 years and ending no earlier than 2011. Five climate indices related to both Atlantic and Pacific Oceans are used in this study: the North Atlantic Oscillation (NAO), the Southern Oscillation Index (SOI), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO), and the Pacific-North American pattern (PNA). A peak-over-threshold approach is used to identify flood peaks, and the relationship between the frequency of flood events and climate drivers is investigated using Poisson regression. The results of this work indicate that changes in the climate system play a significant role in explaining the year-to-year variations in the frequency of flooding over the central United States. Different climate indices are related to the frequency of flood events over different parts of the domain and for different seasons. Analyses related to flood events are extended to examine climate controls on heavy rainfall over this area. The results indicate that the variability of the Atlantic and Pacific Oceans can influence the frequency of heavy rainfall days in a manner similar to what was found for flooding, both in terms of geographic regions and seasonality. Therefore, these results suggest that the recent observed changes in the frequency of flood events over the central United States can be largely attributed to changes in the climate system.

  11. Field-scale relationships among soil properties and shallow groundwater quality.

    PubMed

    Derby, Nathan E; Korom, Scott F; Casey, Francis X M

    2013-01-01

    It is important to understand the link between land surface/soil properties and shallow groundwater quality. To that end, soil properties and near-water-table groundwater chemistry of a shallow, unconfined aquifer were measured on a 100-m grid on a 64-ha irrigated field in southeastern North Dakota. Soil properties and hydrochemistry were compared via multivariate analysis that included product-moment correlations and factor analysis/principal component analysis. Topographic low areas where the water table was in close proximity to the soil surface generally had higher apparent electrical conductivity (ECa ) and higher percent silt and clay than higher positions on the landscape. The majority of the groundwater was characterized by Ca- and Mg-HCO3 type water and was associated with topographic high areas with lower ECa and net groundwater recharge. Small topographic depressions were areas of higher ECa (net groundwater discharge) where salts that precipitated via evapotranspiration and evaporative discharge dissolved and leached to the groundwater during short-term depression-focused recharge events. At this site, groundwater quality and soil ECa were related to surface topography. High-resolution topography and EC(a) measurements are necessary to characterize the land surface/soil properties and surficial groundwater quality at the field-scale and to delineate areas where the shallow groundwater is most susceptible to contamination. PMID:22913586

  12. Southern ocean SST variability and its relationship with ENSO on inter-decadal time scales

    NASA Astrophysics Data System (ADS)

    Yan, Li; Du, Yan; Zhang, Lan

    2013-06-01

    Empirical orthogonal function (EOF) analysis reveals a co-variability of Sea surface temperatures (SSTs) in the Southern Hemisphere (0°-60°S). In the South Indian and Atlantic Oceans, there is a subtropical dipole pattern slanted in the southwest-northeast direction. In the South Pacific Ocean, a meridional tripole structure emerges, whose middle pole co-varies with the dipoles in the South Indian and Atlantic Oceans and is used in this study to track subtropical Pacific variability. The South Indian and Atlantic Ocean dipoles and the subtropical Pacific variability are phase-locked in austral summer. On the inter-decadal time scales, the dipoles in the South Indian and Atlantic Oceans weaken in amplitude after 1979/1980. No such weakening is found in the subtropical South Pacific Ocean. Interestingly, despite the reduced amplitude, the correlation of the Indian Ocean and Atlantic dipoles with El Niño and Southern Oscillation (ENSO) are enhanced after 1979/1980. The same increase in correlation is found for subtropical South Pacific variability after 1979/1980. These inter-decadal modulations imply that the Southern Hemisphere participates in part of the climate shift in the late 1970s. The correlation between Southern Hemisphere SST and ENSO reduces after 2000.

  13. A sleep continuity scale in Alzheimer's disease: validation and relationship with cognitive and functional deterioration.

    PubMed

    Manni, R; Sinforiani, E; Zucchella, C; Terzaghi, M; Rezzani, C

    2013-05-01

    Considering that disrupted sleep may be detrimental to daytime performance in people with dementia, we set out to construct a questionnaire able to identify sleep patterns potentially associated with clinical and functional disease variables in this population. Two subsets of items indicative of patterns of unstable sleep and of disordered rapid eye movement sleep (REM) were selected. The first included items investigating sleep continuity, with low sleep continuity markers considered indicative of high arousability; the second included items investigating the frequency and quality of dreams and the frequency of clinically identifiable REM sleep behaviour disorder episodes. The questionnaire was administered to 140 outpatients with a diagnosis of mild-to-moderate Alzheimer's disease. The Mini-Mental State Examination (MMSE), Activities of Daily Living (ADL), Instrumental Activities of Daily Living, Neuropsychiatric Inventory and Clinical Dementia Rating (CDR) were administered to quantify cognitive, functional and behavioural impairment. A subscale comprising items investigating sleep discontinuity/fragmentation and showing high internal consistency was constructed and found to correlate significantly with variables considered indexes of cognitive and functional deterioration in AD (MMSE, ADL and CDR). Conversely, it did not prove possible to obtain a subscale of dysfunctional REM phenomena. The use of a rapidly and easily administered sleep scale, like the one we constructed, appears to be suitable for early identification and longitudinal monitoring of sleep disturbances in AD. PMID:22622870

  14. The Relationships between Workaholism and Symptoms of Psychiatric Disorders: A Large-Scale Cross-Sectional Study

    PubMed Central

    Griffiths, Mark D.; Sinha, Rajita; Hetland, Jørn

    2016-01-01

    Despite the many number of studies examining workaholism, large-scale studies have been lacking. The present study utilized an open web-based cross-sectional survey assessing symptoms of psychiatric disorders and workaholism among 16,426 workers (Mage = 37.3 years, SD = 11.4, range = 16–75 years). Participants were administered the Adult ADHD Self-Report Scale, the Obsession-Compulsive Inventory-Revised, the Hospital Anxiety and Depression Scale, and the Bergen Work Addiction Scale, along with additional questions examining demographic and work-related variables. Correlations between workaholism and all psychiatric disorder symptoms were positive and significant. Workaholism comprised the dependent variable in a three-step linear multiple hierarchical regression analysis. Basic demographics (age, gender, relationship status, and education) explained 1.2% of the variance in workaholism, whereas work demographics (work status, position, sector, and annual income) explained an additional 5.4% of the variance. Age (inversely) and managerial positions (positively) were of most importance. The psychiatric symptoms (ADHD, OCD, anxiety, and depression) explained 17.0% of the variance. ADHD and anxiety contributed considerably. The prevalence rate of workaholism status was 7.8% of the present sample. In an adjusted logistic regression analysis, all psychiatric symptoms were positively associated with being a workaholic. The independent variables explained between 6.1% and 14.4% in total of the variance in workaholism cases. Although most effect sizes were relatively small, the study’s findings expand our understanding of possible psychiatric predictors of workaholism, and particularly shed new insight into the reality of adult ADHD in work life. The study’s implications, strengths, and shortcomings are also discussed. PMID:27192149

  15. The Relationships between Workaholism and Symptoms of Psychiatric Disorders: A Large-Scale Cross-Sectional Study.

    PubMed

    Andreassen, Cecilie Schou; Griffiths, Mark D; Sinha, Rajita; Hetland, Jørn; Pallesen, Ståle

    2016-01-01

    Despite the many number of studies examining workaholism, large-scale studies have been lacking. The present study utilized an open web-based cross-sectional survey assessing symptoms of psychiatric disorders and workaholism among 16,426 workers (Mage = 37.3 years, SD = 11.4, range = 16-75 years). Participants were administered the Adult ADHD Self-Report Scale, the Obsession-Compulsive Inventory-Revised, the Hospital Anxiety and Depression Scale, and the Bergen Work Addiction Scale, along with additional questions examining demographic and work-related variables. Correlations between workaholism and all psychiatric disorder symptoms were positive and significant. Workaholism comprised the dependent variable in a three-step linear multiple hierarchical regression analysis. Basic demographics (age, gender, relationship status, and education) explained 1.2% of the variance in workaholism, whereas work demographics (work status, position, sector, and annual income) explained an additional 5.4% of the variance. Age (inversely) and managerial positions (positively) were of most importance. The psychiatric symptoms (ADHD, OCD, anxiety, and depression) explained 17.0% of the variance. ADHD and anxiety contributed considerably. The prevalence rate of workaholism status was 7.8% of the present sample. In an adjusted logistic regression analysis, all psychiatric symptoms were positively associated with being a workaholic. The independent variables explained between 6.1% and 14.4% in total of the variance in workaholism cases. Although most effect sizes were relatively small, the study's findings expand our understanding of possible psychiatric predictors of workaholism, and particularly shed new insight into the reality of adult ADHD in work life. The study's implications, strengths, and shortcomings are also discussed. PMID:27192149

  16. Prediction of Drug Clearance in Premature and Mature Neonates, Infants, and Children ≤2 Years of Age: A Comparison of the Predictive Performance of 4 Allometric Models.

    PubMed

    Mahmood, Iftekhar

    2016-06-01

    The objective of this study was to evaluate the predictive performance of 4 allometric models to predict clearance in pediatric ages ranging from premature neonates to children ≤2 years of age. Four allometric models were used to predict clearances of 28 drugs in children from preterm neonates to 2 years of age (n = 564). The 4 models are (1) basal metabolic rate-dependent model; (2) age-dependent exponent model; (3) an allometric model based on kidney and liver weights as well as kidney and liver blood flow; and (4) an allometric model based on a fixed exponent of 0.75. The predictive performance of these models was evaluated by comparing the predicted clearance of the studied drugs with the observed clearance in an individual child. The results of the study indicated that the 3 new proposed models predicted the mean clearance of the drugs with reasonable accuracy (≤50% prediction error). On the other hand, the exponent of 0.75 produced substantial prediction error. Predicted individual clearance values were ≥50% in approximately 30% of the children by the proposed 3 methods and 73% by exponent 0.75. The 3 new proposed allometric models can predict mean clearances of drugs in children from premature neonates to ≤2 years of age with reasonable accuracy and are of practical value during pediatric drug development. PMID:26437918

  17. Sediment budget variation at watershed scale due to anthropogenic pressures, and its relationship to coastal erosion

    NASA Astrophysics Data System (ADS)

    Aiello, Antonello; Adamo, Maria; Canora, Filomena

    2014-05-01

    forecast coastline fluctuations caused by such anthropogenic interventions. These are valuable information for both the management of and development of future plans for coastal environments and for reducing exposure risk to coastal erosion. The purpose of this study was to compare and to evaluate the suitability of the RUSLE (Revised Universal Soil Loss Equation), RUSLE 3D and USPED (Unit Stream Power-based Erosion Deposition) models in assessing the sediment budget variation at watershed scale. In order to assess the rate of net soil erosion, the three models were applied to the Bradano river basin and to the sub-basin subtended by the San Giuliano Dam. To this end, digital terrain model, products derived from satellite remote sensing (multi-temporal Landsat imagery), soil texture maps and ancillary data were integrated and processed in a GIS. To test the models, the computed soil erosion rates were integrated over the San Giuliano sub-basin surface, and compared with the dam silting value provided by an interregional authority responsible for its management. The three models have proven to be effective in quantifying the soil erosion at watershed scale.

  18. Diversity and relationships of cocirculating modern human rotaviruses revealed using large-scale comparative genomics.

    PubMed

    McDonald, Sarah M; McKell, Allison O; Rippinger, Christine M; McAllen, John K; Akopov, Asmik; Kirkness, Ewen F; Payne, Daniel C; Edwards, Kathryn M; Chappell, James D; Patton, John T

    2012-09-01

    Group A rotaviruses (RVs) are 11-segmented, double-stranded RNA viruses and are primary causes of gastroenteritis in young children. Despite their medical relevance, the genetic diversity of modern human RVs is poorly understood, and the impact of vaccine use on circulating strains remains unknown. In this study, we report the complete genome sequence analysis of 58 RVs isolated from children with severe diarrhea and/or vomiting at Vanderbilt University Medical Center (VUMC) in Nashville, TN, during the years spanning community vaccine implementation (2005 to 2009). The RVs analyzed include 36 G1P[8], 18 G3P[8], and 4 G12P[8] Wa-like genogroup 1 strains with VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 genotype constellations of I1-R1-C1-M1-A1-N1-T1-E1-H1. By constructing phylogenetic trees, we identified 2 to 5 subgenotype alleles for each gene. The results show evidence of intragenogroup gene reassortment among the cocirculating strains. However, several isolates from different seasons maintained identical allele constellations, consistent with the notion that certain RV clades persisted in the community. By comparing the genes of VUMC RVs to those of other archival and contemporary RV strains for which sequences are available, we defined phylogenetic lineages and verified that the diversity of the strains analyzed in this study reflects that seen in other regions of the world. Importantly, the VP4 and VP7 proteins encoded by VUMC RVs and other contemporary strains show amino acid changes in or near neutralization domains, which might reflect antigenic drift of the virus. Thus, this large-scale, comparative genomic study of modern human RVs provides significant insight into how this pathogen evolves during its spread in the community. PMID:22696651

  19. Diversity and Relationships of Cocirculating Modern Human Rotaviruses Revealed Using Large-Scale Comparative Genomics

    PubMed Central

    McKell, Allison O.; Rippinger, Christine M.; McAllen, John K.; Akopov, Asmik; Kirkness, Ewen F.; Payne, Daniel C.; Edwards, Kathryn M.; Chappell, James D.; Patton, John T.

    2012-01-01

    Group A rotaviruses (RVs) are 11-segmented, double-stranded RNA viruses and are primary causes of gastroenteritis in young children. Despite their medical relevance, the genetic diversity of modern human RVs is poorly understood, and the impact of vaccine use on circulating strains remains unknown. In this study, we report the complete genome sequence analysis of 58 RVs isolated from children with severe diarrhea and/or vomiting at Vanderbilt University Medical Center (VUMC) in Nashville, TN, during the years spanning community vaccine implementation (2005 to 2009). The RVs analyzed include 36 G1P[8], 18 G3P[8], and 4 G12P[8] Wa-like genogroup 1 strains with VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 genotype constellations of I1-R1-C1-M1-A1-N1-T1-E1-H1. By constructing phylogenetic trees, we identified 2 to 5 subgenotype alleles for each gene. The results show evidence of intragenogroup gene reassortment among the cocirculating strains. However, several isolates from different seasons maintained identical allele constellations, consistent with the notion that certain RV clades persisted in the community. By comparing the genes of VUMC RVs to those of other archival and contemporary RV strains for which sequences are available, we defined phylogenetic lineages and verified that the diversity of the strains analyzed in this study reflects that seen in other regions of the world. Importantly, the VP4 and VP7 proteins encoded by VUMC RVs and other contemporary strains show amino acid changes in or near neutralization domains, which might reflect antigenic drift of the virus. Thus, this large-scale, comparative genomic study of modern human RVs provides significant insight into how this pathogen evolves during its spread in the community. PMID:22696651

  20. Ecological Relationships of Meso-Scale Distribution in 25 Neotropical Vertebrate Species

    PubMed Central

    Michalski, Lincoln José; Norris, Darren; de Oliveira, Tadeu Gomes; Michalski, Fernanda

    2015-01-01

    Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species

  1. Development of allometric relations for three mangrove species in South Florida for use in the Greater Everglades Ecosystem restoration

    USGS Publications Warehouse

    Smith, T. J., III; Whelan, K.R.T.

    2006-01-01

    Mathematical relations that use easily measured variables to predict difficult-to-measure variables are important to resource managers. In this paper we develop allometric relations to predict total aboveground biomass and individual components of biomass (e.g., leaves, stems, branches) for three species of mangroves for Everglades National Park, Florida, USA. The Greater Everglades Ecosystem is currently the subject of a 7.8-billion-dollar restoration program sponsored by federal, state, and local agencies. Biomass and production of mangroves are being used as a measure of restoration success. A technique for rapid determination of biomass over large areas is required. We felled 32 mangrove trees and separated each plant into leaves, stems, branches, and for Rhizophora mangle L., prop roots. Wet weights were measured in the field and subsamples returned to the laboratory for determination of wet-to-dry weight conversion factors. The diameter at breast height (DBH) and stem height were also measured. Allometric equations were developed for each species for total biomass and components of biomass. We compared our equations with those from the same, or similar, species from elsewhere in the world. Our equations explained ???93% of the variance in total dry weight using DBH. DBH is a better predictor of dry weight than is stem height and DBH is much easier to measure. Furthermore, our results indicate that there are biogeographic differences in allometric relations between regions. For a given DBH, stems of all three species have less mass in Florida than stems from elsewhere in the world. ?? Springer 2006.

  2. Size at the onset of maturity (SOM) revealed in length-weight relationships of brackish amphipods and isopods: An information theory approach

    NASA Astrophysics Data System (ADS)

    Longo, Emanuela; Mancinelli, Giorgio

    2014-01-01

    In amphipods and other small-sized crustaceans, allometric relationships are conventionally analysed by fitting the standard model Y = a·Xb (X and Y are, e.g., body length and weight, respectively) whose scaling exponent b is assumed to be constant. However, breakpoints in allometric relationships have long been documented in large-sized crustaceans, ultimately determined by ontogenetic, abrupt variations in the value of b. Here, the existence of breakpoints in length-weight relationships was investigated in four amphipod (i.e., Gammarus aequicauda, Gammarus insensibilis, Microdeutopus gryllotalpa, and Dexamine spinosa) and three isopod species (i.e., Lekanesphaera hookeri, Sphaeroma serratum, and Cymodoce truncata) from three Mediterranean lagoons. The power of two candidate linear models fitted to log10-transformed data - a simple model assuming a constant exponent b and a segmented model assuming b to vary after a breakpoint - was compared using a parsimonious selection strategy based on the Akaike information criterion. The segmented model with a breakpoint provided the most accurate fitting of length-weight data in the majority of the species analysed; non-conclusive results were obtained only for D. spinosa and C. truncata, of which a limited number of specimens was examined. Model parameters were consistent for amphipod and isopod species collected across the three different habitats; the generality of the results was further supported by a literature search confirming that the identified breakpoints corresponded with ontogenetic discontinuities related with sexual maturation in all the species investigated. In this study, segmented regression models were revealed to provide a statistically accurate and biologically meaningful description of length-weight relationships of common amphipod and isopod species. The methodological limitations of the approach are considered, while the practical implications for secondary production estimates are discussed.

  3. On the relationship between ecosystem-scale hyperspectral reflectance and CO2 exchange in European mountain grasslands

    NASA Astrophysics Data System (ADS)

    Balzarolo, M.; Vescovo, L.; Hammerle, A.; Gianelle, D.; Papale, D.; Wohlfahrt, G.

    2014-07-01

    In this paper we explore the use of hyperspectral reflectance measurements and vegetation indices (VIs) derived therefrom in estimating carbon dioxide (CO2) fluxes (net ecosystem exchange - NEE; gross primary production - GPP), and some key ecophysiological variables related to NEE and GPP (light use efficiency - ɛ; initial quantum yield - α; and GPP at saturating light - GPPmax) for grasslands. Hyperspectral reflectance data (400-1000 nm), CO2 fluxes and biophysical parameters were measured at three grassland sites located in European mountain regions. The relationships between CO2 fluxes, ecophysiological variables and VIs derived using all two-band combinations of wavelengths available from the whole hyperspectral data space were analysed. We found that hyperspectral VIs generally explained a large fraction of the variability in the investigated dependent variables and that they generally exhibited more skill in estimating midday and daily average GPP and NEE, as well as GPPmax, than α and ɛ. Relationships between VIs and CO2 fluxes and ecophysiological parameters were site-specific, likely due to differences in soils, vegetation parameters and environmental conditions. Chlorophyll and water content related VIs (e.g. CI, NPCI, WI), reflecting seasonal changes in biophysical parameters controlling the photosynthesis process, explained the largest fraction of variability in most of the dependent variables. A limitation of the hyperspectral sensors is that their cost is still high and the use laborious. At the eddy covariance with a limited budget and without technical support, we suggest to use at least dual or four channels low cost sensors in the the following spectral regions: 400-420 nm; 500-530 nm; 750-770 nm; 780-800 nm and 880-900 nm. In addition, our findings have major implications for up-scaling terrestrial CO2 fluxes to larger regions and for remote and proximal sensing sampling and analysis strategies and call for more cross-site synthesis studies

  4. Patient-reported outcomes in multiple sclerosis: Relationships among existing scales and the development of a brief measure.

    PubMed

    Chua, Alicia S; Glanz, Bonnie I; Guarino, Anthony J; Cook, Sandra L; Greeke, Emily E; Little, Grace E; Chitnis, Tanuja; Healy, Brian C

    2015-11-01

    Several patient-reported outcome (PRO) measures are commonly used in multiple sclerosis (MS) research, but the relationship among items across measures is uncertain. We proposed to evaluate the associations between items from a standard battery of PRO measures used in MS research and to develop a brief, reliable and valid instrument measure by combining these items into a single measure. Subjects (N = 537) enrolled in CLIMB complete a PRO battery that includes the Center for Epidemiologic Studies Depression Scale, Medical Outcomes Study Modified Social Support Survey, Modified Fatigue Impact Scale and Multiple Sclerosis Quality of Life-54. Subjects were randomly divided into two samples: calibration (n = 269) and validation (n = 268). In the calibration sample, an Exploratory Factor Analysis (EFA) was used to identify latent constructs within the battery. The model constructed based on the EFA was evaluated in the validation sample using Confirmatory Factor Analysis (CFA), and reliability and validity were assessed for the final measure. The EFA in the calibration sample revealed an eight factor solution, and a final model with one second-order factor along with the eight first-order factors provided the best fit. The model combined items from each of the four parent measures, showing important relationships among the parent measures. When the model was fit using the validation sample, the results confirmed the validity and reliability of the model. A brief PRO for MS (BPRO-MS) that combines MS-related psychosocial and quality of life domains can be used to assess overall functioning in mildly disabled MS patients. PMID:26590669

  5. On the relationship between ecosystem-scale hyperspectral reflectance and CO2 exchange in European mountain grasslands

    NASA Astrophysics Data System (ADS)

    Balzarolo, M.; Vescovo, L.; Hammerle, A.; Gianelle, D.; Papale, D.; Tomelleri, E.; Wohlfahrt, G.

    2015-05-01

    In this paper we explore the skill of hyperspectral reflectance measurements and vegetation indices (VIs) derived from these in estimating carbon dioxide (CO2) fluxes of grasslands. Hyperspectral reflectance data, CO2 fluxes and biophysical parameters were measured at three grassland sites located in European mountain regions using standardized protocols. The relationships between CO2 fluxes, ecophysiological variables, traditional VIs and VIs derived using all two-band combinations of wavelengths available from the whole hyperspectral data space were analysed. We found that VIs derived from hyperspectral data generally explained a large fraction of the variability in the investigated dependent variables but differed in their ability to estimate midday and daily average CO2 fluxes and various derived ecophysiological parameters. Relationships between VIs and CO2 fluxes and ecophysiological parameters were site-specific, likely due to differences in soils, vegetation parameters and environmental conditions. Chlorophyll and water-content-related VIs explained the largest fraction of variability in most of the dependent variables. Band selection based on a combination of a genetic algorithm with random forests (GA-rF) confirmed that it is difficult to select a universal band region suitable across the investigated ecosystems. Our findings have major implications for upscaling terrestrial CO2 fluxes to larger regions and for remote- and proximal-sensing sampling and analysis strategies and call for more cross-site synthesis studies linking ground-based spectral reflectance with ecosystem-scale CO2 fluxes.

  6. Conductivity Scaling Relationships of Nanostructured Membranes based on Hydrated Protic Polymerized Ionic Liquids: Effect of Domain Spacing

    NASA Astrophysics Data System (ADS)

    Sanoja, Gabriel; Popere, Bhooshan; Beckingham, Bryan; Evans, Christopher; Lynd, Nathaniel; Segalman, Rachel

    Elucidating the relationship between chemical structure, morphology, and ionic conductivity is essential for designing novel materials for electrochemical applications. In this work, the effect of lamellar domain spacing (d) on ionic conductivity (σ) is investigated for a model system of hydrated block copolymer based on a protic polymerized ionic liquid. We present a strategy that allows for the synthesis of a well-defined series of narrowly dispersed PS- b - PIL with constant volume fraction of ionic liquid moieties (fIL ~ 0.39). These materials self-assemble into ordered lamellar morphologies with variable domain spacing (23-59 nm) as demonstrated by SAXS. PS- b - PIL membranes exhibit ionic conductivities above 10-4 S/cm at room temperature, which are independent of domain spacing. The conductivity scaling relationship demonstrated in this work suggests that a mechanically robust membrane can be designed without compromising its ability to transport ions. In addition, PIL-based membranes exhibit lower water uptake (λ = 10) in comparison with many proton-conducting systems reported elsewhere. The low water content of these materials makes them promising candidates for solar-fuels electrochemical devices.

  7. Examining the form-function relationship of convective organization and the larger scale with observations and models

    NASA Astrophysics Data System (ADS)

    Riley, Emily Marie

    This work uses a two-pronged approach to study the form-function relationship of convective organization and the larger scale. Form is simply the visual shape of convection and function is how the convection and larger scale interact. First, CloudSat observations are used to study cloud modulation during the Madden-Julian Oscillation (MJO). Second, a cloud systems resolving model (CSRM) with parameterized large-scale dynamics is used to examine how convective organization affects the interdependence of convection and the larger-scale. Using CloudSat observations, cloud type, total cloud cover, and temperature and moisture evolution are document across MJO phases. Deep cloud types were classified as wide or narrow as a proxy for designating organized and unorganized convective systems. For locally defined phases, the MJO exhibits a familiar progression of cloud types from shallow clouds mixed with deep, isolated convection in the growing stages of the MJO, to deep, widespread, organized convection during the mature stages, to more anvil dominated conditions during the decay stages. Comparison to the convectively coupled Kelvin wave reveals both wave types exhibit similar cloud type evolution, though, the MJO was found to be modulated more by moisture variation, while the Kelvin wave was modulated more by temperature variations. In terms of globally defined MJO phases, the wide deep precipitating systems were modulated more than other cloud types by MJO phases, with the well-known progression of cloud cover from the Indian Ocean to the central Pacific. The narrow deep precipitating systems only propagated from the Indian Ocean to the Maritime Continent. The modeling component of this work involved periodic domains, where convective organization was controlled by adding shear to a three-dimensional (3D) isotropic CSRM domain or by altering the 3D domain to be longer and narrower, until eventually becoming a 2D domain. Snapshots of convective activity in various

  8. Scale

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2009-01-01

    The common approach to scaling, according to Christopher Dede, a professor of learning technologies at the Harvard Graduate School of Education, is to jump in and say, "Let's go out and find more money, recruit more participants, hire more people. Let's just keep doing the same thing, bigger and bigger." That, he observes, "tends to fail, and fail…

  9. Assessing the relationship between environmental factors and malaria vector breeding sites in Swaziland using multi-scale remotely sensed data.

    PubMed

    Dlamini, Sabelo Nick; Franke, Jonas; Vounatsou, Penelope

    2015-01-01

    Many entomological studies have analyzed remotely sensed data to assess the relationship between malaria vector distribution and the associated environmental factors. However, the high cost of remotely sensed products with high spatial resolution has often resulted in analyses being conducted at coarse scales using open-source, archived remotely sensed data. In the present study, spatial prediction of potential breeding sites based on multi-scale remotely sensed information in conjunction with entomological data with special reference to presence or absence of larvae was realized. Selected water bodies were tested for mosquito larvae using the larva scooping method, and the results were compared with data on land cover, rainfall, land surface temperature (LST) and altitude presented with high spatial resolution. To assess which environmental factors best predict larval presence or absence, Decision Tree methodology and logistic regression techniques were applied. Both approaches showed that some environmental predictors can reliably distinguish between the two alternatives (existence and non-existence of larvae). For example, the results suggest that larvae are mainly present in very small water pools related to human activities, such as subsistence farming that were also found to be the major determinant for vector breeding. Rainfall, LST and altitude, on the other hand, were less useful as a basis for mapping the distribution of breeding sites. In conclusion, we found that models linking presence of larvae with high-resolution land use have good predictive ability of identifying potential breeding sites. PMID:26054511

  10. Constructing Model of Relationship among Behaviors and Injuries to Products Based on Large Scale Text Data on Injuries

    NASA Astrophysics Data System (ADS)

    Nomori, Koji; Kitamura, Koji; Motomura, Yoichi; Nishida, Yoshifumi; Yamanaka, Tatsuhiro; Komatsubara, Akinori

    In Japan, childhood injury prevention is urgent issue. Safety measures through creating knowledge of injury data are essential for preventing childhood injuries. Especially the injury prevention approach by product modification is very important. The risk assessment is one of the most fundamental methods to design safety products. The conventional risk assessment has been carried out subjectively because product makers have poor data on injuries. This paper deals with evidence-based risk assessment, in which artificial intelligence technologies are strongly needed. This paper describes a new method of foreseeing usage of products, which is the first step of the evidence-based risk assessment, and presents a retrieval system of injury data. The system enables a product designer to foresee how children use a product and which types of injuries occur due to the product in daily environment. The developed system consists of large scale injury data, text mining technology and probabilistic modeling technology. Large scale text data on childhood injuries was collected from medical institutions by an injury surveillance system. Types of behaviors to a product were derived from the injury text data using text mining technology. The relationship among products, types of behaviors, types of injuries and characteristics of children was modeled by Bayesian Network. The fundamental functions of the developed system and examples of new findings obtained by the system are reported in this paper.

  11. [Comparison of 2 depression scales and their relationship with negative and akinetic symptoms in stabilized schizophrenic patients].

    PubMed

    Langlois-Thery, S; Dollfus, S; Lesieur, P; Petit, M

    1994-01-01

    Since the Bleuler's early writings, studies in schizophrenia have often shown a frequent occurrence of depression in the context of schizophrenia and also its implications for the morbidity and mortality of schizophrenic patients. The wide variability in the prevalence of depression (between 7 to 70% in post-psychotic period) is due in part to the difficulty in clearly separating depressive symptoms from akinesia induced by neuroleptic or negative symptoms and to the lack of a valid assessment of depressive symptoms in schizophrenic patients. Under these conditions, a better understanding of depressive symptomatology in schizophrenia seems to be necessary to go further in this area of research with clinical and therapeutical purposes. The "Echelle de Ralentissement Dépressif" (ERD, Widlöcher, 1983) was studied in a sample of 53 schizophrenic patients to determinate whether ERD composed of three subscores (motor, ideic and subjective) could be able to evaluate the subjective depressive symptomatology and whether its measure would be independent of negative symptoms or akinesia. Pearson's correlations and correlations with variables partialled out were used to compare ERD to Montgomery and Asberg Depression Rating Scale (MADRS, 1979) and to establish their relationship with Positive And Negative Syndrome Scale (PANSS< Kay, 1987) and an Extrapyramidal Symptom Rating Scale (ESRS, Chouinard & Ross-Chouinard, 1980). Fifty three in or outpatients (35 males and 18 females, mean age +/- standard deviation = 38.26 +/- 9.82) were evaluated in a stable condition (i.e., when the psychotic symptomatology and the neuroleptic treatment have been stabilized since 4 weeks). According to DESM III-R criteria, 49 patients met the diagnosis of schizophrenia (2 schizoaffective disorders and 2 schizophreniform disorders).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7828511

  12. Colony-Level Differences in the Scaling Rules Governing Wood Ant Compound Eye Structure

    PubMed Central

    Perl, Craig D.; Niven, Jeremy E.

    2016-01-01

    Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers’ eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population. PMID:27068571

  13. Colony-Level Differences in the Scaling Rules Governing Wood Ant Compound Eye Structure.

    PubMed

    Perl, Craig D; Niven, Jeremy E

    2016-01-01

    Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers' eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population. PMID:27068571

  14. Whole-bone scaling of the avian pelvic limb

    PubMed Central

    Doube, Michael; Yen, Stephanie C W; Kłosowski, Michał M; Farke, Andrew A; Hutchinson, John R; Shefelbine, Sandra J

    2012-01-01

    Birds form the largest extant group of bipedal animals and occupy a broad range of body masses, from grams to hundreds of kilograms. Additionally, birds occupy distinct niches of locomotor behaviour, from totally flightless strong runners such as the ratites (moa, kiwi, ostrich) to birds that may walk, dabble on water or fly. We apply a whole-bone approach to investigate allometric scaling trends in the pelvic limb bones (femur, tibiotarsus, tarsometatarsus) from extant and recently extinct birds of greatly different size, and compare scaling between birds in four locomotor groups; flightless, burst-flying, dabbling and flying. We also compare scaling of birds’ femoral cross-sectional properties to data previously collected from cats. Scaling exponents were not significantly different between the different locomotor style groups, but elevations of the scaling relationships revealed that dabblers (ducks, geese, swans) have particularly short and slender femora compared with other birds of similar body mass. In common with cats, but less pronounced in birds, the proximal and distal extrema of the bones scaled more strongly than the diaphysis, and in larger birds the diaphysis occupied a smaller proportion of bone length than in smaller birds. Cats and birds have similar femoral cross-sectional area (CSA) for the same body mass, yet birds’ bone material is located further from the bone’s long axis, leading to higher second and polar moments of area and a greater inferred resistance to bending and twisting. The discrepancy in the relationship between outer diameter to CSA may underlie birds’ reputation for having ‘light’ bones. PMID:22606941

  15. Allometric variation among juvenile, adult male and female eastern bearded dragons Pogona barbata (Cuvier, 1829), with comments on the behavioural implications.

    PubMed

    Wotherspoon, Danny; Burgin, Shelley

    2011-02-01

    The functional significance of allometric change in reptiles has received limited attention and the reason for such changes has been regarded as 'obscure'. In this paper we report data on the Australian Pogona barbata, the eastern bearded dragon, from across their range and review changes in allometric growth among juveniles, and adult males and females and consider the functional relevance of these changes. There were significant differences in the population for mass, tail length, tail width, rear leg length and jaw length. These differences were consistent with differences required in locomotor performance and thus habitat use, together with access to different preferred dietary components. PMID:21236651

  16. Dynamic relationships between body size, species richness, abundance, and energy use in a shallow marine epibenthic faunal community

    PubMed Central

    Labra, Fabio A; Hernández-Miranda, Eduardo; Quiñones, Renato A

    2015-01-01

    We study the temporal variation in the empirical relationships among body size (S), species richness (R), and abundance (A) in a shallow marine epibenthic faunal community in Coliumo Bay, Chile. We also extend previous analyses by calculating individual energy use (E) and test whether its bivariate and trivariate relationships with S and R are in agreement with expectations derived from the energetic equivalence rule. Carnivorous and scavenger species representing over 95% of sample abundance and biomass were studied. For each individual, body size (g) was measured and E was estimated following published allometric relationships. Data for each sample were tabulated into exponential body size bins, comparing species-averaged values with individual-based estimates which allow species to potentially occupy multiple size classes. For individual-based data, both the number of individuals and species across body size classes are fit by a Weibull function rather than by a power law scaling. Species richness is also a power law of the number of individuals. Energy use shows a piecewise scaling relationship with body size, with energetic equivalence holding true only for size classes above the modal abundance class. Species-based data showed either weak linear or no significant patterns, likely due to the decrease in the number of data points across body size classes. Hence, for individual-based size spectra, the SRA relationship seems to be general despite seasonal forcing and strong disturbances in Coliumo Bay. The unimodal abundance distribution results in a piecewise energy scaling relationship, with small individuals showing a positive scaling and large individuals showing energetic equivalence. Hence, strict energetic equivalence should not be expected for unimodal abundance distributions. On the other hand, while species-based data do not show unimodal SRA relationships, energy use across body size classes did not show significant trends, supporting energetic

  17. Dynamic relationships between body size, species richness, abundance, and energy use in a shallow marine epibenthic faunal community.

    PubMed

    Labra, Fabio A; Hernández-Miranda, Eduardo; Quiñones, Renato A

    2015-01-01

    We study the temporal variation in the empirical relationships among body size (S), species richness (R), and abundance (A) in a shallow marine epibenthic faunal community in Coliumo Bay, Chile. We also extend previous analyses by calculating individual energy use (E) and test whether its bivariate and trivariate relationships with S and R are in agreement with expectations derived from the energetic equivalence rule. Carnivorous and scavenger species representing over 95% of sample abundance and biomass were studied. For each individual, body size (g) was measured and E was estimated following published allometric relationships. Data for each sample were tabulated into exponential body size bins, comparing species-averaged values with individual-based estimates which allow species to potentially occupy multiple size classes. For individual-based data, both the number of individuals and species across body size classes are fit by a Weibull function rather than by a power law scaling. Species richness is also a power law of the number of individuals. Energy use shows a piecewise scaling relationship with body size, with energetic equivalence holding true only for size classes above the modal abundance class. Species-based data showed either weak linear or no significant patterns, likely due to the decrease in the number of data points across body size classes. Hence, for individual-based size spectra, the SRA relationship seems to be general despite seasonal forcing and strong disturbances in Coliumo Bay. The unimodal abundance distribution results in a piecewise energy scaling relationship, with small individuals showing a positive scaling and large individuals showing energetic equivalence. Hence, strict energetic equivalence should not be expected for unimodal abundance distributions. On the other hand, while species-based data do not show unimodal SRA relationships, energy use across body size classes did not show significant trends, supporting energetic

  18. Sexual Dimorphism and Allometric Effects Associated With the Wing Shape of Seven Moth Species of Sphingidae (Lepidoptera: Bombycoidea).

    PubMed

    de Camargo, Willian Rogers Ferreira; de Camargo, Nícholas Ferreira; Corrêa, Danilo do Carmo Vieira; de Camargo, Amabílio J Aires; Diniz, Ivone Rezende

    2015-01-01

    Sexual dimorphism is a pronounced pattern of intraspecific variation in Lepidoptera. However, moths of the family Sphingidae (Lepidoptera: Bombycoidea) are considered exceptions to this rule. We used geometric morphometric techniques to detect shape and size sexual dimorphism in the fore and hindwings of seven hawkmoth species. The shape variables produced were then subjected to a discriminant analysis. The allometric effects were measured with a simple regression between the canonical variables and the centroid size. We also used the normalized residuals to assess the nonallometric component of shape variation with a t-test. The deformations in wing shape between sexes per species were assessed with a regression between the nonreduced shape variables and the residuals. We found sexual dimorphism in both wings in all analyzed species, and that the allometric effects were responsible for much of the wing shape variation between the sexes. However, when we removed the size effects, we observed shape sexual dimorphism. It is very common for females to be larger than males in Lepidoptera, so it is expected that the shape of structures such as wings suffers deformations in order to preserve their function. However, sources of variation other than allometry could be a reflection of different reproductive flight behavior (long flights in search for sexual mates in males, and flight in search for host plants in females). PMID:26206895

  19. Sexual Dimorphism and Allometric Effects Associated With the Wing Shape of Seven Moth Species of Sphingidae (Lepidoptera: Bombycoidea)

    PubMed Central

    de Camargo, Nícholas Ferreira; Corrêa, Danilo do Carmo Vieira; de Camargo, Amabílio J. Aires; Diniz, Ivone Rezende

    2015-01-01

    Sexual dimorphism is a pronounced pattern of intraspecific variation in Lepidoptera. However, moths of the family Sphingidae (Lepidoptera: Bombycoidea) are considered exceptions to this rule. We used geometric morphometric techniques to detect shape and size sexual dimorphism in the fore and hindwings of seven hawkmoth species. The shape variables produced were then subjected to a discriminant analysis. The allometric effects were measured with a simple regression between the canonical variables and the centroid size. We also used the normalized residuals to assess the nonallometric component of shape variation with a t-test. The deformations in wing shape between sexes per species were assessed with a regression between the nonreduced shape variables and the residuals. We found sexual dimorphism in both wings in all analyzed species, and that the allometric effects were responsible for much of the wing shape variation between the sexes. However, when we removed the size effects, we observed shape sexual dimorphism. It is very common for females to be larger than males in Lepidoptera, so it is expected that the shape of structures such as wings suffers deformations in order to preserve their function. However, sources of variation other than allometry could be a reflection of different reproductive flight behavior (long flights in search for sexual mates in males, and flight in search for host plants in females). PMID:26206895

  20. Scales

    ScienceCinema

    Murray Gibson

    2010-01-08

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain ? a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  1. Scales

    SciTech Connect

    Murray Gibson

    2007-04-27

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain — a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  2. Relationship between grip strength and newly diagnosed nonalcoholic fatty liver disease in a large-scale adult population.

    PubMed

    Meng, Ge; Wu, Hongmei; Fang, Liyun; Li, Chunlei; Yu, Fei; Zhang, Qing; Liu, Li; Du, Huanmin; Shi, Hongbin; Xia, Yang; Guo, Xiaoyan; Liu, Xing; Bao, Xue; Su, Qian; Gu, Yeqing; Yang, Huijun; Bin Yu; Wu, Yuntang; Sun, Zhong; Niu, Kaijun

    2016-01-01

    Enhanced muscle strength is often related to improved insulin sensitivity and secretion, control of lipid metabolism, and increased secretion of myokines. These factors have emerged as important mechanisms involved in the development and progression of nonalcoholic fatty liver disease (NAFLD), implying that muscle strength may be a useful predictor for NAFLD. We aimed to assess the relationship between grip strength (GS) and NAFLD in a large-scale adult population. GS was assessed using an electronic hand-grip dynamometer, and NAFLD was diagnosed by the liver ultrasonography. Multiple logistic regression analysis was used to assess the relationship between the quartiles of GS per body weight and the prevalence of NAFLD. After adjusting for potentially confounding factors, the odds ratios (95% confidence interval) for overall NAFLD, NAFLD with normal alanine aminotransferase levels, and NAFLD with elevated alanine aminotransferase levels across the quartiles of GS were 1.00 (reference), 0.89 (0.78, 1.01), 0.77 (0.67, 0.89), and 0.67 (0.57, 0.79); 1.00 (reference), 0.91 (0.80, 1.04), 0.79 (0.68, 0.92), and 0.72 (0.61, 0.85); 1.00 (reference), 0.77 (0.61, 0.98), 0.67 (0.51, 0.86), and 0.53 (0.40, 0.71) (all P for trend < 0.01), respectively. This is the first study shows that increased GS is independently associated with lower prevalence of NAFLD. PMID:27616599

  3. The Toronto Hospital Alertness Test scale: relationship to daytime sleepiness, fatigue, and symptoms of depression and anxiety

    PubMed Central

    Shahid, Azmeh; Chung, Sharon A; Maresky, Lance; Danish, Affan; Bingeliene, Arina; Shen, Jianhua; Shapiro, Colin M

    2016-01-01

    Objective The Toronto Hospital Alertness Test (THAT) scale was designed to measure alertness, defined as the capacity of the mind to respond appropriately to external and internal stimuli. The present study’s aim is to determine normative values of alertness on the THAT and to explore the relationship among excessive daytime sleepiness, fatigue, depressive symptoms, and alertness. Methods Normative data were collected from 60 healthy males and females. To explore the relationship among alertness, daytime sleepiness, fatigue, depression, and anxiety, data were collected from charts of sleep clinic patients. All study subjects completed measures for fatigue, sleepiness, depressive symptoms, and anxiety. Results The average score on the THAT was 34.9±7.2 (range 22–50) for the control group. The cutoff score for the THAT, indicative of clinically significant reduced alertness, was determined to be ≤20.5 (mean −2 SD). THAT alertness scores were found to be modestly, significantly, and negatively correlated with fatigue levels (r=−0.39, P<0.001), depressive symptoms (r=−0.53, P<0.001), and anxiety symptoms (r=−0.41, P<0.001). No correlations were found between alertness levels and daytime sleepiness. Regression analyses revealed a significant model (F=19.9, P<0.001, adjusted R2=0.35) with depressive symptoms (P<0.001) and fatigue (P=0.006) emerging as the only significant predictors of scores on the THAT. Conclusion The findings of this study support that sleepiness is not the same as poor alertness. Depressive symptoms and fatigue, but not sleepiness, were found to have a strong and significant impact on levels of alertness. This is the first study to link poor alertness to depressive symptoms. PMID:26855603

  4. Do clouds save the great barrier reef? satellite imagery elucidates the cloud-SST relationship at the local scale.

    PubMed

    Leahy, Susannah M; Kingsford, Michael J; Steinberg, Craig R

    2013-01-01

    Evidence of global climate change and rising sea surface temperatures (SSTs) is now well documented in the scientific literature. With corals already living close to their thermal maxima, increases in SSTs are of great concern for the survival of coral reefs. Cloud feedback processes may have the potential to constrain SSTs, serving to enforce an "ocean thermostat" and promoting the survival of coral reefs. In this study, it was hypothesized that cloud cover can affect summer SSTs in the tropics. Detailed direct and lagged relationships between cloud cover and SST across the central Great Barrier Reef (GBR) shelf were investigated using data from satellite imagery and in situ temperature and light loggers during two relatively hot summers (2005 and 2006) and two relatively cool summers (2007 and 2008). Across all study summers and shelf positions, SSTs exhibited distinct drops during periods of high cloud cover, and conversely, SST increases during periods of low cloud cover, with a three-day temporal lag between a change in cloud cover and a subsequent change in SST. Cloud cover alone was responsible for up to 32.1% of the variation in SSTs three days later. The relationship was strongest in both El Niño (2005) and La Niña (2008) study summers and at the inner-shelf position in those summers. SST effects on subsequent cloud cover were weaker and more variable among study summers, with rising SSTs explaining up to 21.6% of the increase in cloud cover three days later. This work quantifies the often observed cloud cooling effect on coral reefs. It highlights the importance of incorporating local-scale processes into bleaching forecasting models, and encourages the use of remote sensing imagery to value-add to coral bleaching field studies and to more accurately predict risks to coral reefs. PMID:23894649

  5. Do Clouds Save the Great Barrier Reef? Satellite Imagery Elucidates the Cloud-SST Relationship at the Local Scale

    PubMed Central

    Leahy, Susannah M.; Kingsford, Michael J.; Steinberg, Craig R.

    2013-01-01

    Evidence of global climate change and rising sea surface temperatures (SSTs) is now well documented in the scientific literature. With corals already living close to their thermal maxima, increases in SSTs are of great concern for the survival of coral reefs. Cloud feedback processes may have the potential to constrain SSTs, serving to enforce an “ocean thermostat” and promoting the survival of coral reefs. In this study, it was hypothesized that cloud cover can affect summer SSTs in the tropics. Detailed direct and lagged relationships between cloud cover and SST across the central Great Barrier Reef (GBR) shelf were investigated using data from satellite imagery and in situ temperature and light loggers during two relatively hot summers (2005 and 2006) and two relatively cool summers (2007 and 2008). Across all study summers and shelf positions, SSTs exhibited distinct drops during periods of high cloud cover, and conversely, SST increases during periods of low cloud cover, with a three-day temporal lag between a change in cloud cover and a subsequent change in SST. Cloud cover alone was responsible for up to 32.1% of the variation in SSTs three days later. The relationship was strongest in both El Niño (2005) and La Niña (2008) study summers and at the inner-shelf position in those summers. SST effects on subsequent cloud cover were weaker and more variable among study summers, with rising SSTs explaining up to 21.6% of the increase in cloud cover three days later. This work quantifies the often observed cloud cooling effect on coral reefs. It highlights the importance of incorporating local-scale processes into bleaching forecasting models, and encourages the use of remote sensing imagery to value-add to coral bleaching field studies and to more accurately predict risks to coral reefs. PMID:23894649

  6. Evaluating the relationship between topography and groundwater using outputs from a continental-scale integrated hydrology model

    NASA Astrophysics Data System (ADS)

    Condon, Laura E.; Maxwell, Reed M.

    2015-08-01

    We study the influence of topography on groundwater fluxes and water table depths across the contiguous United States (CONUS). Groundwater tables are often conceptualized as subdued replicas of topography. While it is well known that groundwater configuration is also controlled by geology and climate, nonlinear interactions between these drivers within large real-world systems are not well understood and are difficult to characterize given sparse groundwater observations. We address this limitation using the fully integrated physical hydrology model ParFlow to directly simulate groundwater fluxes and water table depths within a complex heterogeneous domain that incorporates all three primary groundwater drivers. Analysis is based on a first of its kind, continental-scale, high-resolution (1 km), groundwater-surface water simulation spanning more than 6.3 million km2. Results show that groundwater fluxes are most strongly driven by topographic gradients (as opposed to gradients in pressure head) in humid regions with small topographic gradients or low conductivity. These regions are generally consistent with the topographically controlled groundwater regions identified in previous studies. However, we also show that areas where topographic slopes drive groundwater flux do not generally have strong correlations between water table depth and elevation. Nonlinear relationships between topography and water table depth are consistent with groundwater flow systems that are dominated by local convergence and could also be influenced by local variability in geology and climate. One of the strengths of the numerical modeling approach is its ability to evaluate continental-scale groundwater behavior at a high resolution not possible with other techniques. This article was corrected on 11 SEP 2015. See the end of the full text for details.

  7. Investigating the relationship between a soils classification and the spatial parameters of a conceptual catchment-scale hydrological model

    NASA Astrophysics Data System (ADS)

    Dunn, S. M.; Lilly, A.

    2001-10-01

    There are now many examples of hydrological models that utilise the capabilities of Geographic Information Systems to generate spatially distributed predictions of behaviour. However, the spatial variability of hydrological parameters relating to distributions of soils and vegetation can be hard to establish. In this paper, the relationship between a soil hydrological classification Hydrology of Soil Types (HOST) and the spatial parameters of a conceptual catchment-scale model is investigated. A procedure involving inverse modelling using Monte-Carlo simulations on two catchments is developed to identify relative values for soil related parameters of the DIY model. The relative values determine the internal variability of hydrological processes as a function of the soil type. For three out of the four soil parameters studied, the variability between HOST classes was found to be consistent across two catchments when tested independently. Problems in identifying values for the fourth 'fast response distance' parameter have highlighted a potential limitation with the present structure of the model. The present assumption that this parameter can be related simply to soil type rather than topography appears to be inadequate. With the exclusion of this parameter, calibrated parameter sets from one catchment can be converted into equivalent parameter sets for the alternate catchment on the basis of their HOST distributions, to give a reasonable simulation of flow. Following further testing on different catchments, and modifications to the definition of the fast response distance parameter, the technique provides a methodology whereby it is possible to directly derive spatial soil parameters for new catchments.

  8. Roles of Spatial Scale and Rarity on the Relationship between Butterfly Species Richness and Human Density in South Africa

    PubMed Central

    Mecenero, Silvia; Altwegg, Res; Colville, Jonathan F.; Beale, Colin M.

    2015-01-01

    Wildlife and humans tend to prefer the same productive environments, yet high human densities often lead to reduced biodiversity. Species richness is often positively correlated with human population density at broad scales, but this correlation could also be caused by unequal sampling effort leading to higher species tallies in areas of dense human activity. We examined the relationships between butterfly species richness and human population density at five spatial resolutions ranging from 2' to 60' across South Africa. We used atlas-type data and spatial interpolation techniques aimed at reducing the effect of unequal spatial sampling. Our results confirm the general positive correlation between total species richness and human population density. Contrary to our expectations, the strength of this positive correlation did not weaken at finer spatial resolutions. The patterns observed using total species richness were driven mostly by common species. The richness of threatened and restricted range species was not correlated to human population density. None of the correlations we examined were particularly strong, with much unexplained variance remaining, suggesting that the overlap between butterflies and humans is not strong compared to other factors not accounted for in our analyses. Special consideration needs to be made regarding conservation goals and variables used when investigating the overlap between species and humans for biodiversity conservation. PMID:25915899

  9. How to unravel relationships between soil structure and preferential flow in structured soils with fast tomography at the continuum scale?

    NASA Astrophysics Data System (ADS)

    Sammartino, S.; Lissy, A. S.; Bogner, C.; Cornu, S.

    2015-12-01

    The modeling of water flow in the vadose zone and the understanding of processes and mechanisms that control preferential flow is still a challenge for many environmental issues. Since a long time, tridimensional X-ray images have been used to characterize the structures of intact soil cores. Conversely, imaging of water dynamics in soil structures was scarcely developed except on quite small samples in the order of a few centimeters to a few millimeters. As soil structure is a key-controlling factor, the understanding of the complex relationships between the topology and morphology of the pore space on flow distribution and hydraulic properties cannot be undertaken on such small samples. Therefore, we recently proposed the visualization and characterization of flow processes at the core scale (soil volumes of dimensions above 10 cm) with 3D image sequences acquired in a X-ray medical scanner. Last generation of these scanners combining a helical acquisition mode to the multislice capability can now provide very short acquisition times in the order of few seconds for a decimeter column. The 3D image sequences acquired during simulated rainfall events within the scanner were processed and analyzed with new ad hoc tools. Results will focus on 1) the recognition of the functional part of the macropore network related to the flow distribution, 2) its comparison to the entire structure and 3) the estimation of the macroscopic surface exchange between the active macropore network and the soil matrix obtained during the recording of water infiltration.

  10. Century-scale causal relationships between global drought conditions and the state of the Pacific and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Sun, Qiaohong; Miao, Chiyuan; Duan, Qingyun

    2016-04-01

    Drought is one of the costliest and least understood natural hazards. The El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO) are atmosphere-ocean coupled modes of climate variability that occur in the Pacific and Atlantic Oceans. In this study, the Granger causality test is used to examine the effects of ENSO, PDO, and NAO on global drought conditions. The results show robust relationships between drought conditions and the ocean states, as assessed through a multi-index (SPEI and SPI) and multiscalar (3-month and 12-month) evaluation. The influence of ENSO events is widespread, dominating about 40% of the global land droughts. Southern and western North America, northern South America, and eastern Russia are more influenced by PDO. Results show that NAO influence on drought is not restricted to Europe and includes northern Africa. The role of NAO is most evident at 3-month time scale. Moreover, the results provide evidence that drought conditions can be affected by multiple factors. ENSO and PDO may reinforce each other to dominate climate variability over North America and northern South America. Climate variability in southern Europe and northern Africa may be forced by the concurrence of ENSO and NAO. The spatial patterns of the influence of ocean states on global droughts provide valuable information for improving drought forecasting.

  11. Event-scale relationships between surface velocity, temperature and chlorophyll in the coastal ocean, as seen by satellite

    NASA Technical Reports Server (NTRS)

    Strub, P. Ted

    1991-01-01

    The overall goal of this project was to increase our understanding of processes which determine the temporally varying distributions of surface chlorophyll pigment concentration and surface temperature in the California Current System (CCS) on the time-scale of 'events', i.e., several days to several weeks. We also proposed to investigate seasonal and regional differences in these events. Additionally, we proposed to evaluate methods of estimating surface velocities and horizontal transport of pigment and heat from sequences of AVHRR and CZCS images. The four specific objectives stated in the original proposal were to: (1) test surface current estimates made from sequences of both SST and color images using variations of the statistical method of Emery et al. (1986) and estimate the uncertainties in these satellite-derived surface currents; (2) characterize the spatial and temporal relationships of chlorophyll and temperature in rapidly evolving features for which adequate imagery exist and evaluate the contribution of these events to monthly and seasonal averages; (3) use the methods tested in (1) to determine the nature of the velocity fields in the CCS; and (4) compare the currents, temperature, and currents in different seasons and in different geographic regions.

  12. Prediction of Young׳s modulus of trabeculae in microscale using macro-scale׳s relationships between bone density and mechanical properties.

    PubMed

    Cyganik, Łukasz; Binkowski, Marcin; Kokot, Grzegorz; Rusin, Tomasz; Popik, Paulina; Bolechała, Filip; Nowak, Roman; Wróbel, Zygmunt; John, Antoni

    2014-08-01

    According to the literature, there are many mathematical relationships between density of the trabecular bone and mechanical properties obtained in macro-scale testing. In micro-scale, the measurements provide only the ranges of Young׳s modulus of trabeculae, but there are no experimentally tested relationships allowing the calculation of the distribution of Young׳s modulus of trabeculae within these experimental ranges. This study examined the applicability of relationships between bone density and mechanical properties obtained in macro-scale testing for the calculation of Young׳s modulus distribution in micro-scale. Twelve cubic specimens from eleven femoral heads were cut out and micro-computed tomography (micro-CT) scanned. A mechanical compression test and Digital Image Correlation (DIC) measurements were performed to obtain the experimental displacement and strain full-field evaluation for each specimen. Five relationships between bone density and Young׳s modulus were selected for the test; those were given by Carter and Hayes (1977), Ciarelli et al. (2000), Kaneko et al. (2004), Keller (1994) for the human femur, and Li and Aspden, 1997. Using these relationships, five separate finite element (FE) models were prepared, with different distribution of Young׳s modulus of trabeculae for each specimen. In total, 60 FE analyses were carried out. The obtained displacement and strain full-field measurements from numerical calculations and experiment were compared. The results indicate that the highest accuracy of the numerical calculation was obtained for the Ciarelli et al. (2000) relationship, where the relative error was 17.87% for displacements and 50.94 % for strains. Therefore, the application of the Ciarelli et al. (2000) relationship in the microscale linear FE analysis is possible, but mainly to determine bone displacement. PMID:24837330

  13. The scaling of eye size with body mass in birds

    PubMed Central

    Brooke, M. de L.; Hanley, S.; Laughlin, S. B.

    1999-01-01

    We developed a simple method that uses skulls to estimate the diameter, and hence the mass, of birds' eyes. Allometric analysis demonstrated that, within five orders (parrots, pigeons, petrels, raptors and owls) and across 104 families of flying birds, eye mass is proportional to (body mass)0.68 over a range of body masses (6 g to 11.3 kg). As expected from their habits and visual ecology, raptors and owls have enlarged eyes, with masses 1.4 and 2.2 times greater than average birds of the same weight. Taking existing relationships for flight speed on body mass, we find that resolution increases close to (flight speed)1.333. Consequently, large birds resolve objects at a longer time to contact than small birds. Eye radius and skull size co-vary in strict proportion, suggesting common physiological, aerodynamic and mechanical constraints. Because eye mass scales close to brain mass, metabolic rate and information processing could also be limiting, but the precise factors determining the scaling of eye to body have not been identified.

  14. Development and Validation of the Relationship and Motivation (REMO) Scale to Assess Students' Perceptions of Peers and Teachers as Motivators in Adolescence

    ERIC Educational Resources Information Center

    Raufelder, Diana; Drury, Kate; Jagenow, Danilo; Hoferichter, Frances; Bukowski, William

    2013-01-01

    Factor analyses of a newly developed measure designed to measure early adolescents' perceptions of peers and teachers as sources of scholastic motivation were conducted with a diverse sample of 7th and 8th grade students (N = 1088) in secondary schools. The Relationship and Motivation (REMO) scales measure perceptions of peers (P-REMO) and…

  15. Career Adapt-Abilities Scale in a French-Speaking Swiss Sample: Psychometric Properties and Relationships to Personality and Work Engagement

    ERIC Educational Resources Information Center

    Rossier, Jerome; Zecca, Gregory; Stauffer, Sarah D.; Maggiori, Christian; Dauwalder, Jean-Pierre

    2012-01-01

    The aim of this study was to analyze the psychometric properties of the Career Adapt-Abilities Scale (CAAS) in a French-speaking Swiss sample and its relationship with personality dimensions and work engagement. The heterogeneous sample of 391 participants (M[subscript age] = 39.59, SD = 12.30) completed the CAAS-International and a short version…

  16. Exploring the Relationship between Static and Dynamic Vertical Scaling from Cross-Sectional and Longitudinal Design Perspectives

    ERIC Educational Resources Information Center

    Wang, Shudong; Jiao, Hong; Jiang, Yanming

    2009-01-01

    The concept of dynamic vertical scaling (DVS) from longitudinal point of view has been proposed as comparing to traditional vertical scaling or static vertical scaling (SVS) from cross-sectional perspective. The effects of differences between DVS and SVS on large-scale student achievements have been investigated. The potential application of DVS…

  17. Comparative biology of the crab Goniopsis cruentata: geographic variation of body size, sexual maturity, and allometric growth

    NASA Astrophysics Data System (ADS)

    de Lira, José Jonathas Pereira Rodrigues; Calado, Tereza Cristina dos Santos; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

    2015-12-01

    Geographic variation of phenotypic traits is common across species and is often associated with variation in environmental conditions. Here, we found larger bodies and larger size at maturity in a northward, lower latitude population of the crab Goniopsis cruentata, which inhabits a hotter, drier environment in comparison with a southward, higher latitude population. Furthermore, the juvenile male gonopods grow more relative to body size in the population characterized by maturation at a smaller size. In contrast, the female abdomen widens at a higher rate among the late maturing population. These results provide further evidence that local environmental conditions play a role in phenotypic variation between populations inhabiting different latitudes. Moreover, they also show that variation in size at maturity and body size can lead to divergent allometric patterns of sexual characteristics that can have a sex-specific response.

  18. Relationships between landslide occurrences and rainfall patterns at different time scale: application to the Barcelonnette Basin (South French Alps)

    NASA Astrophysics Data System (ADS)

    Remaitre, Alexandre; Malet, Jean-Philippe

    2010-05-01

    Triggering of mass movements can be divided in three general types: i) development of local perched water tables in the subsoil leading to shallow slope instabilities and possible gravitational flows, ii) long-lasting rise in permanent water tables leading to more deep-seated slope instabilities, and iii) intense runoff causing channel-bed erosion and debris flows. Types i) and iii) are usually observed during heavy storms characterized by high rainfall intensities (hourly and daily rainfall); type ii) is usually observed through increasing water content in the subsoil due to previous rainfalls (monthly rainfall). The objective of this work is to analyze the relationships between mass movement (landslide and debris flows) events and different pattern of rainfalls at different time scale. The study has been performed in the Barcelonnette Basin (South French Alps) where an important database on mass-movement events is available. Still two centuries, about 600 references with exact date and location of triggering have been recorded. The rainfall pattern has been recorded in six meteorological stations. Principally, data are available for 24h-periods and only a small amount of new installed stations include automated recording with 6-minute data. A detailed study has been performed for 145 well known mass-movement events. For each of these events, a study of the rainfall conditions for different time scale has been performed, and for some relevant events, the regional climate conditions has been determined by defining the related weather type (synoptic point of view). The analyses of the rainstorm episodes indicates that the determination of a clear rainfall threshold for shallow landslide and debris flows in the Barcelonnette Basin is still very difficult; this has to be put in relation with the geomorphologic settings of the different slopes and torrents. Nevertheless, two main rainfall conditions can be clearly distinguished: i) persistent rainstorms with low

  19. The Acoustic Signature of Woodford Shale and Upscale Relationship from Nano-Scale Mechanical Properties and Mineralogy

    NASA Astrophysics Data System (ADS)

    Tran, M. H.; Abousleiman, Y. N.; Hoang, S. K.; Ortega, A. J.; Bobko, C.; Ulm, F.

    2007-12-01

    The complex composition of shale, the most encountered and problematic lithology in the Earth's crust, has puzzled many researchers attempting to find the key for understanding their micro- and macro-scale acoustic and mechanical signatures. Recent advances in nano-technology, in particular the progress of the Atomic Force Microscope (AFM) base indentation technique, have made it possible to mechanically study porous material at a nano scale (10-9 m) and consequently have allowed linking shale mechanical properties to intrinsic micro- and macro-properties such as porosity, packing density, and mineralogy. Based on more than 20,000 nano- indentation tests conducted on a number of shales with varying physical properties, a GeoGenomeTM model was developed to upscale macroscopic shale mechanical parameters from mineralogy composition, porosity, and packing density. In this work, the mechanical properties such as the elastic stiffness coefficients, Cij, and the anisotropic Biot's Pore Pressure Coefficients, αij, of the Woodford shale, were acquired using sonic log data and Ultra-Sonic Pulse Velocity (UPV) measurements conducted on preserved retrieved shale core samples from a 200-ft well drilled in the Woodford formation, in Oklahoma. Furthermore, the dependency of the Cij and αij, on applied stresses and the relationship between the dynamic moduli and the quasi-static moduli were also investigated using an array of piezoelectric crystals mounted around the samples while subjecting the samples to different applied stress states using a series of tri-axial tests. X-Ray Diffraction (XRD) and mercury injection tests were also performed on the retrieved core samples to obtain mineralogy composition and porosity of the shale at different depths. Comparison of the simulated mechanical and poromechanical properties and stiffness coefficients using the Quantitative GeoGenomeTM Mineralogy Simulator (QGGMSTM) with field and acoustic lab measurements showed excellent agreement

  20. Geographic scale matters in detecting the relationship between neighbourhood food environments and obesity risk: an analysis of driver license records in Salt Lake County, Utah

    PubMed Central

    Fan, Jessie X; Hanson, Heidi A; Zick, Cathleen D; Brown, Barbara B; Kowaleski-Jones, Lori; Smith, Ken R

    2014-01-01

    Objectives Empirical studies of the association between neighbourhood food environments and individual obesity risk have found mixed results. One possible cause of these mixed findings is the variation in neighbourhood geographic scale used. The purpose of this paper was to examine how various neighbourhood geographic scales affected the estimated relationship between food environments and obesity risk. Design Cross-sectional secondary data analysis. Setting Salt Lake County, Utah, USA. Participants 403 305 Salt Lake County adults 25–64 in the Utah driver license database between 1995 and 2008. Analysis Utah driver license data were geo-linked to 2000 US Census data and Dun & Bradstreet business data. Food outlets were classified into the categories of large grocery stores, convenience stores, limited-service restaurants and full-service restaurants, and measured at four neighbourhood geographic scales: Census block group, Census tract, ZIP code and a 1 km buffer around the resident's house. These measures were regressed on individual obesity status using multilevel random intercept regressions. Outcome Obesity. Results Food environment was important for obesity but the scale of the relevant neighbourhood differs for different type of outlets: large grocery stores were not significant at all four geographic scales, limited-service restaurants at the medium-to-large scale (Census tract or larger) and convenience stores and full-service restaurants at the smallest scale (Census tract or smaller). Conclusions The choice of neighbourhood geographic scale can affect the estimated significance of the association between neighbourhood food environments and individual obesity risk. However, variations in geographic scale alone do not explain the mixed findings in the literature. If researchers are constrained to use one geographic scale with multiple categories of food outlets, using Census tract or 1 km buffer as the neighbourhood geographic unit is likely to

  1. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone.

    PubMed

    Osland, Michael J; Day, Richard H; Larriviere, Jack C; From, Andrew S

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone. PMID:24971938

  2. Aboveground Allometric Models for Freeze-Affected Black Mangroves (Avicennia germinans): Equations for a Climate Sensitive Mangrove-Marsh Ecotone

    PubMed Central

    Osland, Michael J.; Day, Richard H.; Larriviere, Jack C.; From, Andrew S.

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone. PMID:24971938

  3. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone

    USGS Publications Warehouse

    Osland, Michael J.; Day, Richard H.; Larriviere, Jack C.; From, Andrew S.

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  4. Relationships among the Y balance test, Berg Balance Scale, and lower limb strength in middle-aged and older females

    PubMed Central

    Lee, Dong-Kyu; Kang, Min-Hyeok; Lee, Tae-Sik; Oh, Jae-Seop

    2015-01-01

    Background: Older females have less dynamic postural control and muscle strength than do middle-aged females. Aging-related strength losses may limit balancing performance. Objective: The purpose of this study was to investigate the ability of the Y Balance Test (YBT) and lower limb strength to discriminate between females in 2 age groups, the relationship between YBT distance and the Berg Balance Scale (BBS), and the degree to which performance on YBT distance is related to lower limb strength in middle-aged and older females. Method: The 40 healthy, independently active females were divided into 2 groups: older and middle-aged. The participants underwent measurements of YBT distance using the YBT, maximal muscular strength of the lower limbs using a handheld dynamometer, and the BBS. Results: The YBT distance in 3 directions and lower limb muscle strength for both lower limbs were significantly lower in the older adults than in the middle-aged group. A moderate correlation but insignificant correlation was found between the YBT composite distance and the BBS score. In the older females, YBT distance was significantly positively correlated with strength of the knee flexor and hip abductor. In the middle-aged group, YBT distance was significantly positively correlated with strength of the knee flexor and hip extensor. Conclusions: Performance on the YBT was influenced by the strength of lower limb. We suggested that YBT can be used to alternative as a measurement of dynamic balance. Proper training programs for older people could include not only strengthening exercises but also YBT performance to improve balance. PMID:26039033

  5. Pathways of Leymus chinensis Individual Aboveground Biomass Decline in Natural Semiarid Grassland Induced by Overgrazing: A Study at the Plant Functional Trait Scale

    PubMed Central

    Wang, Zhen; Wu, Xinhong; Li, Xinle; Hu, Jing; Shi, Hongxiao; Guo, Fenghui; Zhang, Yong; Hou, Xiangyang

    2015-01-01

    Natural grassland productivity, which is based on an individual plant’s aboveground biomass (AB) and its interaction with herbivores, can obviously affect terrestrial ecosystem services and the grassland’s agricultural production. As plant traits have been linked to both AB and ecosystem success, they may provide a useful approach to understand the changes in individual plants and grassland productivity in response to grazing on a generic level. Unfortunately, the current lack of studies on how plant traits affect AB affected by herbivores leaves a major gap in our understanding of the mechanism of grassland productivity decline. This study, therefore, aims to analyze the paths of overgrazing-induced decline in the individual AB of Leymus chinensis (the dominant species of meadow-steppe grassland in northern China) on a plant functional trait scale. Using a paired-sampling approach, we compared the differences in the functional traits of L. chinensis in long-term grazing-excluded and experimental grazing grassland plots over a continuous period of approximately 20 years (located in meadow steppe lands in Hailar, Inner Mongolia, China). We found a highly significant decline in the individual height and biomass (leaf, stem, and the whole plant) of L. chinensis as a result of overgrazing. Biomass allocation and leaf mass per unit area were significantly affected by the variation in individual size. Grazing clearly enhanced the sensitivity of the leaf-to-stem biomass ratio in response to variation in individual size. Moreover, using a method of standardized major axis estimation, we found that the biomass in the leaves, stems, and the plant as a whole had highly significant allometric scaling with various functional traits. Also, the slopes of the allometric equations of these relationships were significantly altered by grazing. Therefore, a clear implication of this is that grazing promotes an asymmetrical response of different plant functional traits to variation

  6. Pathways of Leymus chinensis Individual Aboveground Biomass Decline in Natural Semiarid Grassland Induced by Overgrazing: A Study at the Plant Functional Trait Scale.

    PubMed

    Li, Xiliang; Liu, Zhiying; Wang, Zhen; Wu, Xinhong; Li, Xinle; Hu, Jing; Shi, Hongxiao; Guo, Fenghui; Zhang, Yong; Hou, Xiangyang

    2015-01-01

    Natural grassland productivity, which is based on an individual plant's aboveground biomass (AB) and its interaction with herbivores, can obviously affect terrestrial ecosystem services and the grassland's agricultural production. As plant traits have been linked to both AB and ecosystem success, they may provide a useful approach to understand the changes in individual plants and grassland productivity in response to grazing on a generic level. Unfortunately, the current lack of studies on how plant traits affect AB affected by herbivores leaves a major gap in our understanding of the mechanism of grassland productivity decline. This study, therefore, aims to analyze the paths of overgrazing-induced decline in the individual AB of Leymus chinensis (the dominant species of meadow-steppe grassland in northern China) on a plant functional trait scale. Using a paired-sampling approach, we compared the differences in the functional traits of L. chinensis in long-term grazing-excluded and experimental grazing grassland plots over a continuous period of approximately 20 years (located in meadow steppe lands in Hailar, Inner Mongolia, China). We found a highly significant decline in the individual height and biomass (leaf, stem, and the whole plant) of L. chinensis as a result of overgrazing. Biomass allocation and leaf mass per unit area were significantly affected by the variation in individual size. Grazing clearly enhanced the sensitivity of the leaf-to-stem biomass ratio in response to variation in individual size. Moreover, using a method of standardized major axis estimation, we found that the biomass in the leaves, stems, and the plant as a whole had highly significant allometric scaling with various functional traits. Also, the slopes of the allometric equations of these relationships were significantly altered by grazing. Therefore, a clear implication of this is that grazing promotes an asymmetrical response of different plant functional traits to variation in

  7. Satellite-scale Estimates of the "b Parameter" Relating Vegetation Water Content and SMOS Optical Thickness

    NASA Astrophysics Data System (ADS)

    Patton, J. C.; Hornbuckle, B. K.

    2013-12-01

    Microwave radiation emitted by Earth's land surface is primarily determined by soil moisture and vegetation. One of the effects of vegetation on surface microwave emissions is often termed the "vegetation optical thickness" or "vegetation opacity" and is often abbreviated as tau. Retrievals of soil moisture from microwave radiometer measurements requires knowledge of tau. The Soil Moisture and Ocean Salinity (SMOS) satellite measures microwave radiation at multiple incidence angles, enabling the simultaneous retrieval of soil moisture and tau. Other soil moisture satellites, such as the upcoming Soil Moisture Active Passive (SMAP) satellite, only measure at single incidence angles and may need auxiliary sources of tau data in order to retrieve soil moisture. One proposed method for estimating tau for these satellites is by relating reflectance data, e.g. the normalized difference vegetation index, to vegetation water content (VWC), then relating VWC to tau. VWC and tau can be related through the b parameter, i.e. tau = b x VWC. Values of b for different land cover types have been estimated from tower (~1 m) and airplane (~10-100 m) data, but have not been measured at the satellite scale (~10 km). Estimating b at the satellite scale from measurements at smaller scales is difficult because the effective value of b in a satellite pixel may not be well represented by linear weighted average based on the fraction of each land cover type in the pixel. However, by relating county crop yields, estimated by the USDA National Agricultural Statistics Service, to measurements of SMOS tau, and by using certain allometric relationships, such as the ratio of water to dry matter and the harvest index of crops, we can estimate b at the satellite scale. We have used this method to estimate b for each Iowa county for the years 2010-2012. Initial results suggest that b may change year to year; our current estimates for b in Iowa range from 0.065 in 2010 to 0.100 in 2012. These

  8. The Perception of False Self Scale for Adolescents: Reliability, Validity, and Longitudinal Relationships with Depressive and Anxious S