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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. Size structuring and allometric scaling relationships in coral reef fishes.

    PubMed

    Dunic, Jillian C; Baum, Julia K

    2017-05-01

    Temperate marine fish communities are often size-structured, with predators consuming increasingly larger prey and feeding at higher trophic levels as they grow. Gape limitation and ontogenetic diet shifts are key mechanisms by which size structuring arises in these communities. Little is known, however, about size structuring in coral reef fishes. Here, we aimed to advance understanding of size structuring in coral reef food webs by examining the evidence for these mechanisms in two groups of reef predators. Given the diversity of feeding modes amongst coral reef fishes, we also compared gape size-body size allometric relationships across functional groups to determine whether they are reliable indicators of size structuring. We used gut content analysis and quantile regressions of predator size-prey size relationships to test for evidence of gape limitation and ontogenetic niche shifts in reef piscivores (n = 13 species) and benthic invertivores (n = 3 species). We then estimated gape size-body size allometric scaling coefficients for 21 different species from four functional groups, including herbivores/detritivores, which are not expected to be gape-limited. We found evidence of both mechanisms for size structuring in coral reef piscivores, with maximum prey size scaling positively with predator body size, and ontogenetic diet shifts including prey type and expansion of prey size. There was, however, little evidence of size structuring in benthic invertivores. Across species and functional groups, absolute and relative gape sizes were largest in piscivores as expected, but gape size-body size scaling relationships were not indicative of size structuring. Instead, relative gape sizes and mouth morphologies may be better indicators. Our results provide evidence that coral reef piscivores are size-structured and that gape limitation and ontogenetic niche shifts are the mechanisms from which this structure arises. Although gape allometry was not indicative of

  3. 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.

  4. 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

  5. New allometric scaling relationships and applications for dose and toxicity extrapolation.

    PubMed

    Cao, Qiming; Yu, Jimmy; Connell, Des

    2014-01-01

    Allometric scaling between metabolic rate, size, body temperature, and other biological traits has found broad applications in ecology, physiology, and particularly in toxicology and pharmacology. Basal metabolic rate (BMR) was observed to scale with body size and temperature. However, the mass scaling exponent was increasingly debated whether it should be 2/3, 3/4, or neither, and scaling with body temperature also attracted recent attention. Based on thermodynamic principles, this work reports 2 new scaling relationships between BMR, size, temperature, and biological time. Good correlations were found with the new scaling relationships, and no universal scaling exponent can be obtained. The new scaling relationships were successfully validated with external toxicological and pharmacological studies. Results also demonstrated that individual extrapolation models can be built to obtain scaling exponent specific to the interested group, which can be practically applied for dose and toxicity extrapolations.

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

    PubMed

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

    2014-10-01

    Allometric biomass allocation theory predicts that leaf biomass (M L ) scaled isometrically with stem (M S ) and root (M R ) biomass, and thus above-ground biomass (leaf and stem) (M A ) and root (M R ) 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 M L and M S scaled in an isometric or a nearly isometric manner with M R , as well as M A to M R 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 M L versus M S and M L versus M R , but not for M S versus M R and M A versus M R . We conclude, therefore, that a nearly isometric scaling relationship of M A versus M R holds true within each of the studied woody species and across them irrespective the negative scaling relationship between leaf and stem.

  7. Allometric scaling in-vitro

    PubMed Central

    Ahluwalia, Arti

    2017-01-01

    About two decades ago, West and coworkers established a model which predicts that metabolic rate follows a three quarter power relationship with the mass of an organism, based on the premise that tissues are supplied nutrients through a fractal distribution network. Quarter power scaling is widely considered a universal law of biology and it is generally accepted that were in-vitro cultures to obey allometric metabolic scaling, they would have more predictive potential and could, for instance, provide a viable substitute for animals in research. This paper outlines a theoretical and computational framework for establishing quarter power scaling in three-dimensional spherical constructs in-vitro, starting where fractal distribution ends. Allometric scaling in non-vascular spherical tissue constructs was assessed using models of Michaelis Menten oxygen consumption and diffusion. The models demonstrate that physiological scaling is maintained when about 5 to 60% of the construct is exposed to oxygen concentrations less than the Michaelis Menten constant, with a significant concentration gradient in the sphere. The results have important implications for the design of downscaled in-vitro systems with physiological relevance. PMID:28169362

  8. Allometric scaling in-vitro

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Arti

    2017-02-01

    About two decades ago, West and coworkers established a model which predicts that metabolic rate follows a three quarter power relationship with the mass of an organism, based on the premise that tissues are supplied nutrients through a fractal distribution network. Quarter power scaling is widely considered a universal law of biology and it is generally accepted that were in-vitro cultures to obey allometric metabolic scaling, they would have more predictive potential and could, for instance, provide a viable substitute for animals in research. This paper outlines a theoretical and computational framework for establishing quarter power scaling in three-dimensional spherical constructs in-vitro, starting where fractal distribution ends. Allometric scaling in non-vascular spherical tissue constructs was assessed using models of Michaelis Menten oxygen consumption and diffusion. The models demonstrate that physiological scaling is maintained when about 5 to 60% of the construct is exposed to oxygen concentrations less than the Michaelis Menten constant, with a significant concentration gradient in the sphere. The results have important implications for the design of downscaled in-vitro systems with physiological relevance.

  9. 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.

  10. Allometric scaling of pegylated liposomal anticancer drugs.

    PubMed

    Caron, Whitney P; Clewell, Harvey; Dedrick, Robert; Ramanathan, Ramesh K; Davis, Whitney L; Yu, Ning; Tonda, Margaret; Schellens, Jan H; Beijnen, Jos H; Zamboni, William C

    2011-10-01

    Pegylated liposomal formulations contain lipid conjugated to polyethylene glycol. The disposition of encapsulated drug is dictated by the composition of the liposome, thus altering the pharmacokinetic (PK) profile of the drug. Allometric scaling is based on a power-log relationship between body weight (W) and drug clearance (CL) among mammals and has been used to compare the disposition of nonliposomal drugs across species. The objectives of this study were to use allometric scaling to: (1) compare the disposition of pegylated liposomal drugs across speciesand determine the best scaling model and (2) predict PK parameters of pegylated liposomal drugs in humans. The PK of pegylated liposomal CKD-602 (S-CKD602), doxorubicin (Doxil®), and cisplatin (SPI-077) were compared. PK studies ofS-CKD602, Doxil®, and SPI-077 were performed at the maximum tolerated dose (MTD) in male and female mice, rats, dogs and patients with refractory solid tumors. The allometric equation used to evaluate the relationship between W and CL in each species was CL = a(W)(m) (a = empirical coefficient; m = allometric exponent). Substitution of physiological variables other than body weight, such as factors representative of the mononuclear phagocyte system (MPS) were evaluated. Dedrick Plots and Maximum Life-Span Potential (MLP) were used to determine scaling feasibility. Standard allometry demonstrated a relationship between clearance of S-CKD602, Doxil®, and SPI-077 and body, spleen, liver, and kidney weights, total monocyte count, and spleen and liver blood flow. However, using scaling to predict CL of these agents in humans often resulted in differences >30%. Despite a strong correlation between body weight and MPS-associated variables with CL among preclinical species, the use of the equations did not predict CL. Thus, new methods of allometric scaling and measures of MPS function need to be developed.

  11. 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

  12. 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

  13. Allometric scaling of plant life history.

    PubMed

    Marbà, Núria; Duarte, Carlos M; Agustí, Susana

    2007-10-02

    Plant mortality and birth rates are critical components of plant life history affecting the stability of plant populations and the ecosystems they form. Although allometric theory predicts that both plant birth and mortality rates should be size-dependent, this prediction has not yet been tested across plants ranging the full size spectrum. Here we show that both population mortality and population birth rates scale as the -(1/4) power and plant lifespan as the (1/4) power of plant mass across plant species spanning from the tiniest phototrophs to the largest trees. Whereas the controls on plant lifespans are as yet poorly understood, our findings suggest that plant mortality rates have evolved to match population birth rates, thereby helping to maintain plant communities in equilibrium and optimizing plant life histories.

  14. 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)…

  15. Allometric scaling of Wingate anaerobic powertest scores in women.

    PubMed

    Hetzler, Ronald K; Stickley, Christopher D; Kimura, Iris E

    2011-03-01

    In this study, we developed allometric exponents for scaling Wingate anaerobic test (WAnT) power data that are effective 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) and mean power (MP) were established. Allometric exponents were applied to WAnT scores for an independent sample (n=31) to assess external validity. PP and MP were 477.0 W (SD = 80.0) and 372.6 W (SD = 61.5), respectively. Allometrice exponents for PP and MP scaled for BM were b = 0.92 and b = 0.76, respectively, and for LBM they were b = 0.93 and b = 0.91, respectively. In the independent sample, these exponents produced correlations between allometrically scaled PP and MP and BM of r = -.02 and r = .02, respectively. Correlations between allometrically scaled PP and MP and LBM were r = .004 and r = -.02, respectively. The allometric exponents were effective in partialing out the effect of BM for PP and MP and demonstrated acceptable levels of external validity when applied to an independent sample. The allometric exponents and normative values provide a useful tool for comparing WAnT scores in college-age women without the confounding effects of BM or LBM.

  16. 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.

  17. 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

  18. Multi-scaling allometric analysis for urban and regional development

    NASA Astrophysics Data System (ADS)

    Chen, Yanguang

    2017-01-01

    The concept of allometric growth is based on scaling relations, and it has been applied to urban and regional analysis for a long time. However, most allometric analyses were devoted to the single proportional relation between two elements of a geographical system. Few researches focus on the allometric scaling of multielements. In this paper, a process of multiscaling allometric analysis is developed for the studies on spatio-temporal evolution of complex systems. By means of linear algebra, general system theory, and by analogy with the analytical hierarchy process, the concepts of allometric growth can be integrated with the ideas from fractal dimension. Thus a new methodology of geo-spatial analysis and the related theoretical models emerge. Based on the least squares regression and matrix operations, a simple algorithm is proposed to solve the multiscaling allometric equation. Applying the analytical method of multielement allometry to Chinese cities and regions yields satisfying results. A conclusion is reached that the multiscaling allometric analysis can be employed to make a comprehensive evaluation for the relative levels of urban and regional development, and explain spatial heterogeneity. The notion of multiscaling allometry may enrich the current theory and methodology of spatial analyses of urban and regional evolution.

  19. Allometric scaling of mortality rates with body mass in abalones.

    PubMed

    Rossetto, Marisa; De Leo, Giulio A; Bevacqua, Daniele; Micheli, Fiorenza

    2012-04-01

    The existence of an allometric relationship between mortality rates and body mass has been theorized and extensively documented across taxa. Within species, however, the allometry between mortality rates and body mass has received substantially less attention and the consistency of such scaling patterns at the intra-specific level is controversial. We reviewed 73 experimental studies to examine the relationship between mortality rates and body size among seven species of abalone (Haliotis spp.), a marine herbivorous mollusk. Both in the field and in the laboratory, log-transformed mortality rates were negatively correlated with log-transformed individual body mass for all species considered, with allometric exponents remarkably similar among species. This regular pattern confirms previous findings that juvenile abalones suffer higher mortality rates than adult individuals. Field mortality rates were higher overall than those measured in the laboratory, and the relationship between mortality and body mass tended to be steeper in field than in laboratory conditions for all species considered. These results suggest that in the natural environment, additional mortality factors, especially linked to predation, could significantly contribute to mortality, particularly at small body sizes. On the other hand, the consistent allometry of mortality rates versus body mass in laboratory conditions suggests that other sources of mortality, beside predation, are size-dependent in abalone.

  20. Allometric scaling of Wingate anaerobic power test scores in men.

    PubMed

    Stickley, Christopher D; Hetzler, Ronald K; Wages, Jennifer J; Freemyer, Bret G; Kimura, Iris F

    2013-09-01

    This study examined the appropriate magnitude of allometric scaling of the Wingate anaerobic test (WAnT) power data for body mass (BM) and established normative data for the WAnT for adult men. Eighty-three men completed a standard WAnT using 0.1 kg·kg(-1) BM resistance. Allometric exponents and percentile ranks for 1-second peak power (PP), 5-second PP, and mean power (MP) were established. The Predicted Residual Sum of Squares (PRESS) procedure was used to assess external validity while avoiding data splitting. The mean 1-second PP, 5-second PP, and MP were 1,049.1 ± 168.8 W, 1,013.4 ± 158.6 W, and 777.9 ± 105.0 W, respectively. Allometric exponents for 1-second PP, 5-second PP, and MP scaled for BM were b = 0.89, 0.88, and 0.86, respectively. Correlations between allometrically scaled 1-second PP, 5-second PP, and MP, and BM were r = -0.03, -0.03, and -0.02, respectively, suggesting that the allometric exponents derived were effective in partialling out the effect of BM on WAnT values. The PRESS procedure values resulted in small decreases in R² (0.03, 0.04, and 0.02 for 1-second PP, 5-second PP, and MP, respectively) suggesting acceptable levels of external validity when applied to independent samples. The allometric exponents and normative values provide a useful tool for comparing WAnT scores in college-aged females without the confounding effect of BM. It is suggested that exponents of b = 0.89 (1-second PP), b = 0.88 (5-second PP), and b = 0.86 (MP) be used for allometrically scaling WAnT power values in healthy adult men and that the confidence limits for these allometric exponents be considered as 0.66-1.0 for PP and 0.69-1.0 for MP. The use of these exponents in allometric scaling of male WAnT power values provide coaches and practitioners with valid means for comparing power production between individuals without the confounding influence of BM.

  1. 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.

  2. Heterogeneity of cells may explain allometric scaling of metabolic rate.

    PubMed

    Takemoto, Kazuhiro

    2015-04-01

    The origin of allometric scaling of metabolic rate is a long-standing question in biology. Several models have been proposed for explaining the origin; however, they have advantages and disadvantages. In particular, previous models only demonstrate either two important observations for the allometric scaling: the variability of scaling exponents and predominance of 3/4-power law. Thus, these models have a dispute over their validity. In this study, we propose a simple geometry model, and show that a hypothesis that total surface area of cells determines metabolic rate can reproduce these two observations by combining two concepts: the impact of cell sizes on metabolic rate and fractal-like (hierarchical) organization. The proposed model both theoretically and numerically demonstrates the approximately 3/4-power law although several different biological strategies are considered. The model validity is confirmed using empirical data. Furthermore, the model suggests the importance of heterogeneity of cell size for the emergence of the allometric scaling. The proposed model provides intuitive and unique insights into the origin of allometric scaling laws in biology, despite several limitations of the model.

  3. 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.

  4. Thermodynamics constrains allometric scaling of optimal development time in insects.

    PubMed

    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. The

  5. 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

  6. Quantum metabolism explains the allometric scaling of metabolic rates

    PubMed Central

    Demetrius, Lloyd; Tuszynski, J. A.

    2010-01-01

    A general model explaining the origin of allometric laws of physiology is proposed based on coupled energy-transducing oscillator networks embedded in a physical d-dimensional space (d = 1, 2, 3). This approach integrates Mitchell's theory of chemi-osmosis with the Debye model of the thermal properties of solids. We derive a scaling rule that relates the energy generated by redox reactions in cells, the dimensionality of the physical space and the mean cycle time. Two major regimes are found corresponding to classical and quantum behaviour. The classical behaviour leads to allometric isometry while the quantum regime leads to scaling laws relating metabolic rate and body size that cover a broad range of exponents that depend on dimensionality and specific parameter values. The regimes are consistent with a range of behaviours encountered in micelles, plants and animals and provide a conceptual framework for a theory of the metabolic function of living systems. PMID:19734187

  7. Quantum metabolism explains the allometric scaling of metabolic rates.

    PubMed

    Demetrius, Lloyd; Tuszynski, J A

    2010-03-06

    A general model explaining the origin of allometric laws of physiology is proposed based on coupled energy-transducing oscillator networks embedded in a physical d-dimensional space (d = 1, 2, 3). This approach integrates Mitchell's theory of chemi-osmosis with the Debye model of the thermal properties of solids. We derive a scaling rule that relates the energy generated by redox reactions in cells, the dimensionality of the physical space and the mean cycle time. Two major regimes are found corresponding to classical and quantum behaviour. The classical behaviour leads to allometric isometry while the quantum regime leads to scaling laws relating metabolic rate and body size that cover a broad range of exponents that depend on dimensionality and specific parameter values. The regimes are consistent with a range of behaviours encountered in micelles, plants and animals and provide a conceptual framework for a theory of the metabolic function of living systems.

  8. A potential mechanism for allometric trabecular bone scaling in terrestrial mammals

    PubMed Central

    Christen, Patrik; Ito, Keita; van Rietbergen, Bert

    2015-01-01

    Trabecular bone microstructural parameters, including trabecular thickness, spacing, and number, have been reported to scale with animal size with negative allometry, whereas bone volume fraction is animal size-invariant in terrestrial mammals. As for the majority of scaling patterns described in animals, its underlying mechanism is unknown. However, it has also been found that osteocyte density is inversely related to animal size, possibly adapted to metabolic rate, which shows a negative relationship as well. In addition, the signalling reach of osteocytes is limited by the extent of the lacuno-canalicular network, depending on trabecular dimensions and thus also on animal size. Here we propose animal size-dependent variations in osteocyte density and their signalling influence distance as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. Using an established and tested computational model of bone modelling and remodelling, we run simulations with different osteocyte densities and influence distances mimicking six terrestrial mammals covering a large range of body masses. Simulated trabecular structures revealed negative allometric scaling for trabecular thickness, spacing, and number, constant bone volume fraction, and bone turnover rates inversely related to animal size. These results are in agreement with previous observations supporting our proposal of osteocyte density and influence distance variation as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. The inverse relationship between bone turnover rates and animal size further indicates that trabecular bone scaling may be linked to metabolic rather than mechanical adaptations. PMID:25655770

  9. A potential mechanism for allometric trabecular bone scaling in terrestrial mammals.

    PubMed

    Christen, Patrik; Ito, Keita; van Rietbergen, Bert

    2015-03-01

    Trabecular bone microstructural parameters, including trabecular thickness, spacing, and number, have been reported to scale with animal size with negative allometry, whereas bone volume fraction is animal size-invariant in terrestrial mammals. As for the majority of scaling patterns described in animals, its underlying mechanism is unknown. However, it has also been found that osteocyte density is inversely related to animal size, possibly adapted to metabolic rate, which shows a negative relationship as well. In addition, the signalling reach of osteocytes is limited by the extent of the lacuno-canalicular network, depending on trabecular dimensions and thus also on animal size. Here we propose animal size-dependent variations in osteocyte density and their signalling influence distance as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. Using an established and tested computational model of bone modelling and remodelling, we run simulations with different osteocyte densities and influence distances mimicking six terrestrial mammals covering a large range of body masses. Simulated trabecular structures revealed negative allometric scaling for trabecular thickness, spacing, and number, constant bone volume fraction, and bone turnover rates inversely related to animal size. These results are in agreement with previous observations supporting our proposal of osteocyte density and influence distance variation as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. The inverse relationship between bone turnover rates and animal size further indicates that trabecular bone scaling may be linked to metabolic rather than mechanical adaptations.

  10. Mechanical Work and Long-Distance Performance Prediction: the Influence of Allometric Scaling

    PubMed Central

    Tartaruga, Marcus Peikriszwili; Brisswalter, Jeanick; Mota, Carlos Bolli; Alberton, Cristine Lima; Gomeñuka, Natalia Andrea; Peyré-Tartaruga, Leonardo Alexandre

    2013-01-01

    The purpose of this study was to examine the effect of allometric scaling on the relationship between mechanical work and long-distance running performance in recreational runners. Fourteen recreational long-distance runners (male, mean ± SD - age: 29 ± 7 years; body mass: 70.0 ± 10.2 kg; body height: 1.71 ± 0.07 m; maximal oxygen uptake: VO2max 52.0 ± 4.9 ml·kg−1·min−1) performed two tests: a continuous incremental test to volitional exhaustion in order to determine VO2max, and a 6-minute running submaximal test at 3.1 m·s−1, during which segments in the sagittal plane were recorded using a digital camera and the internal (Wint), external (Wext) and total (Wtot) mechanic work, in J·kg−1·m−1, was subsequently calculated. The results indicated a significant correlation between mechanical work and performance, however, the strongest correlations were observed when allometric exponents were used (respectively for Wint, Wext and Wtot; non allometric vs. allometric scaling defined by literature (0.75) or determined mathematically (0.49): r = 0.38 vs. r = 0.44 and r = 0.50; r = 0.80 vs. r = 0.83 and r = 0.82; r = 0.70 vs. r = 0.77 and r = 0.78). These results indicate that mechanical work could be used as a predictor of recreational long-distance performance and an allometric model may improve this prediction. PMID:24235986

  11. An empirical assessment of tree branching networks and implications for plant allometric scaling models.

    PubMed

    Bentley, Lisa Patrick; Stegen, James C; Savage, Van M; Smith, Duncan D; von Allmen, Erica I; Sperry, John S; Reich, Peter B; Enquist, Brian J

    2013-08-01

    Several theories predict whole-tree function on the basis of allometric scaling relationships assumed to emerge from traits of branching networks. To test this key assumption, and more generally, to explore patterns of external architecture within and across trees, we measure branch traits (radii/lengths) and calculate scaling exponents from five functionally divergent species. Consistent with leading theories, including metabolic scaling theory, branching is area preserving and statistically self-similar within trees. However, differences among scaling exponents calculated at node- and whole-tree levels challenge the assumption of an optimised, symmetrically branching tree. Furthermore, scaling exponents estimated for branch length change across branching orders, and exponents for scaling metabolic rate with plant size (or number of terminal tips) significantly differ from theoretical predictions. These findings, along with variability in the scaling of branch radii being less than for branch lengths, suggest extending current scaling theories to include asymmetrical branching and differential selective pressures in plant architectures.

  12. 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.

  13. Allometric scaling laws for water uptake by plant roots.

    PubMed

    Biondini, Mario

    2008-03-07

    This paper develops scaling laws for plant roots of any arbitrary volume and branching configuration that maximize water uptake. Water uptake can occur along any part of the root network, and thus there is no branch-to-branch fluid conservation. Maximizing water uptake, therefore, involves balancing two flows that are inversely related: axial and radial conductivity. The scaling laws are tested against the root data of 1759 plants from 77 herbaceous species, and compared with those from the WBE model. I further discuss whether the scaling laws are invariant to soil water distribution. A summary of some of the results follows. (1) The optimal radius for a single root (no branches) scales with volume as r approximately volume(2/(8+a))(0allometric scaling for root radius branches (r(i+1)=beta*r(i)) is of the form beta=f(N)((2*epsilon(N))/(8+a)), where f(N)=A(N)/(n(b)*(1+A(N))), n(b) is the number of branches, and A(N) and epsilon(N) are functions of the number of root diameter classes (not constants as in the WBE model). (3) For large N, beta converges to the beta from the WBE model. For small N, the beta's for the two models diverge, but are highly correlated. (4) The fractal assumption of volume filling of the WBE model are also met in the root model even though they are not explicitly incorporated into it. (5) The WBE model for rigid tubes is an asymptotic solution for large root systems (large N and biomass). (6) The optimal scaling solutions for the root network appears to be independent of soil water distribution or water demand. The data set used for testing is included in the electronic supplementary archive of the journal.

  14. Curios relationship revealed by looking at long term data sets-The geometry and allometric scaling of diel xylem sap flux in tropical trees.

    PubMed

    Kunert, Norbert

    2016-10-20

    Daily xylem sap flux values (daily Js) and maximum xylem sap flux values (max Js) from 125 tropical trees from different study sites in the Neotropics were compared. A cross species and study site relationship was found between daily and maximum values. The relationship can be expressed as daily Js=6.5x max Js. The geometrical relationship between the maximum xylem sap flux of a given day is thus defining the daily xylem sap flux rates. Assuming a bell-shaped diurnal sap flux course and a relatively constant day length the maximum xylem sap flux is the only possible changing variable to define daily fluxes. Further, this relationship is showing the inertia of the xylem sap flux as a physical object and highlights the delayed response to environmental changes and its subsequent inevitable susceptibility under environmental stress to hydraulic failure.

  15. Allometric scaling of echocardiographic measurements in healthy Spanish foals with different body weight.

    PubMed

    Rovira, S; Muñoz, A; Rodilla, V

    2009-04-01

    Scaling in biology is usually allometric, and therefore, the size of the heart may be expressed as a power function of body weight (BW). The present research analyses the echocardiographic measurements in 68 healthy Spanish foals weighed between 70 and 347kg in order to determine the correct scaling exponent for the allometric equation. The echocardiographic parameters measured were: left ventricular internal dimensions (LVID), free wall thickness (LVFWT), interventricular septum thickness (IVST) at systole (s) and diastole (d), EPSS (distance between the point E of the mitral valve and the interventricular septum), and aorta diameters at the level of the aortic valve (AOD), base of valve leaflets (ABS), sinus of Valsalva (ASV) and sino-tubular junction (AJT). Indices of left ventricular performance were calculated. It was found that LVIDd, IVSTs, AOD, and ASV have a relationship to BW raised to 0.300-0.368 power, whereas left ventricular end-diastolic volume and stroke volume scaled to BW raised to 0.731-0.712 power. With these data, appropriate values can be calculated for normal Spanish foals.

  16. The ratio and allometric scaling of speed, power, and strength in elite male rugby union players.

    PubMed

    Crewther, Blair T; McGuigan, Mike R; Gill, Nicholas D

    2011-07-01

    This study compared the effectiveness of ratio and allometric scaling for normalizing speed, power, and strength in elite male rugby union players. Thirty rugby players (body mass [BM] 107.1 ± 10.1 kg, body height [BH] 187.8 ± 7.1 cm) were assessed for sprinting speed, peak power during countermovement jumps and squat jumps, and horizontal jumping distance. One-repetition maximum strength was assessed during a bench press, chin-up, and back squat. Performance was normalized using ratio and allometric scaling (Y/X), where Y is the performance, X, the body size variable (i.e., BM or BH), and b is the power exponent. An exponent of 1.0 was used during ratio scaling. Allometric scaling was applied using proposed exponents and derived exponents for each data set. The BM and BH variables were significantly related, or close to, performance during the speed, power and/or strength tests (p < 0.001-0.066). Ratio scaling and allometric scaling using proposed exponents were effective in normalizing performance (i.e., no significant correlations) for some of these tests. Allometric scaling with derived exponents normalized performance across all the tests undertaken, thereby removing the confounding effects of BM and BH. In terms of practical applications, allometric scaling with derived exponents may be used to normalize performance between larger rugby forwards and smaller rugby backs, and could provide additional information on rugby players of similar body size. Ratio scaling may provide the best predictive measure of performance (i.e., strongest correlations).

  17. Allometric scaling of brain regions to intra-cranial volume: An epidemiological MRI study.

    PubMed

    de Jong, Laura W; Vidal, Jean-Sébastien; Forsberg, Lars E; Zijdenbos, Alex P; Haight, Thaddeus; Sigurdsson, Sigurdur; Gudnason, Vilmundur; van Buchem, Mark A; Launer, Lenore J

    2017-01-01

    There is growing evidence that sub-structures of the brain scale allometrically to total brain size, that is, in a non-proportional and non-linear way. Here, scaling of different volumes of interest (VOI) to intra-cranial volume (ICV) was examined. It was assessed whether scaling was allometric or isometric and whether scaling coefficients significantly differed from each other. We also tested to what extent allometric scaling of VOI was introduced by the automated segmentation technique. Furthermore, reproducibility of allometric scaling was studied different age groups and study populations. Study samples included samples of cognitively healthy adults from the community-based Age Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik Study) (N = 3,883), the Coronary Artery Risk Development in Young Adults Study (CARDIA) (N =709), and the Alzheimer's Disease Neuroimaging Initiative (ADNI) (N = 180). Data encompassed participants with different age, ethnicity, risk factor profile, and ICV and VOI obtained with different automated MRI segmentation techniques. Our analysis showed that (1) allometric scaling is a trait of all parts of the brain, (2) scaling of neo-cortical white matter, neo-cortical gray matter, and deep gray matter structures including the cerebellum are significantly different from each other, and (3) allometric scaling of brain structures cannot solely be explained by age-associated atrophy, sex, ethnicity, or a systematic bias from study-specific segmentation algorithm, but appears to be a true feature of brain geometry. Hum Brain Mapp 38:151-164, 2017. © 2016 Wiley Periodicals, Inc.

  18. Allometric scaling of chemical restraint associated with inhalant anesthesia in giant anteaters.

    PubMed

    Carregaro, Adriano Bonfim; Gerardi, Patrícia Molina; Honsho, Daniel Kan

    2009-04-01

    This study describes the use of allometric scaling in five giant anteaters (Myrmecophaga tridactyla) submitted for osteosynthesis, gastrostomy, or treatment of burns. Chemical restraint was performed by allometric scaling using the dog as a reference; acepromazine (0.06 mg/kg), diazepam (0.3 mg/kg), ketamine (8.8 mg/kg), and buprenorphine (5.9 microg/kg) were combined, and the animals were maintained under isoflurane anesthesia. Heart rate, respiratory rate, hemoglobin oxygen saturation, temperature, and anesthetic depth were measured. Postoperative treatment consisted of ketoprofen, buprenorphine, and ceftiofur. Anesthetic induction was obtained in 10-15 min, achieving muscle relaxation and absence of excitement. Physiologic parameters were stable during the procedures, and postoperative treatment was effective. Allometric scaling was effective for chemical restraint and postoperative treatment.

  19. Allometric scaling of strength scores in NCAA division I-A football athletes.

    PubMed

    Oba, Yukiya; Hetzler, Ronald K; Stickley, Christopher D; Tamura, Kaori; Kimura, Iris F; Heffernan, Thomas P

    2014-12-01

    This study examined population-specific allometric exponents to control for the effect of body mass (BM) on bench press, clean, and squat strength measures among Division I-A collegiate football athletes. One repetition maximum data were obtained from a university pre-season football strength assessment (bench press, n = 207; clean, n = 88; and squat n = 86) and categorized into 3 groups by positions (line, linebacker, and skill). Regression diagnostics and correlations of scaled strength data to BM were used to assess the efficacy of the allometric scaling model and contrasted with that of ratio scaling and theoretically based allometric exponents of 0.67 and 0.33. The log-linear regression models yielded the following exponents (b): b = 0.559, 0.287, and 0.496 for bench press, clean, and squat, respectively. Correlations between bench press, clean, and squat to BM were r = -0.024, -0.047, and -0.018, respectively, suggesting that the derived allometric exponents were effective in partialling out the effect of BM on these lifts and removing between-group differences. Conversely, unscaled, ratio-scaled, and allometrically scaled (b = 0.67 or 0.33) data resulted in significant differences between groups. It is suggested that the exponents derived in the present study be used for allometrically scaling strength measures in National Collegiate Athletic Association Division I-A football athletes. Use of the normative percentile rank scores provide coaches and trainers with a valid means of judging the effectiveness of their training programs by allowing comparisons between individuals without the confounding influence of BM.

  20. 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

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

    PubMed

    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

  2. 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

  3. 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.

  4. Allometric scaling of electrical excitation and propagation in the mammalian heart.

    PubMed

    Bassil, Guillaume; Zarzoso, Manuel; Noujaim, Sami F

    2016-09-26

    Variations in body mass impose constraints on the structure and function of mammalian species, including those of the cardiovascular system. Numerous biological processes, including cardiovascular parameters, have been shown to scale with body mass (BM) according to the law of allometric scaling: Y=Y =a∙BM(b) (Y, biological process; a, normalization constant; b, scaling exponent, which in many instances is a multiple of ¼). These parameters include heart and breathing rates, intervals and subintervals of the electrocardiogram (ECG), action potential duration (APD), metabolic rate, and temporal properties of ventricular fibrillation. For instance, the hierarchical branching networks of the vascular system, and of the specialized conduction system in the heart have been proposed to be important determinants of allometric scaling. A global and unifying molecular mechanism of allometric scaling has not been put forth, but changes in gene expression have been proposed to play an important role. Even though it is accepted that differences in body size have cardiovascular effects, the use of scaling in the clinical setting is limited. An increase in the clinical utilization of scaling is thought to lead to improved cardiovascular disease diagnosis and management in patients.

  5. Allometric scaling and predicting cycling performance in (well-) trained female cyclists.

    PubMed

    Lamberts, R P; Davidowitz, K J

    2014-03-01

    As female cycling attains greater professionalism, a larger emphasis is placed on the ability to predict and monitor changes in their cycling performance. The main aim of this study was to determine if peak power output (PPO) adjusted for body mass (W · kg-0.32) accurately predicts flat 40-km time trial performance (40 km TT) in female cyclists as found in men. 20 (well-) trained female cyclists completed a PPO test including maximal oxygen consumption (VO2max) and a flat 40 km TT test. Relationships between cycling performance parameters were also compared to the cycling performance of 45 male cyclists. Allometrically scaled PPW (W · kg(-0.32)) most accurately predicted 40 km TT performance in the female cyclists (r = -0.87, p<0.0001) compared to any other method, however different slopes between the parameters were found in the female and male cyclists (p=0.000115). In addition gender differences were also found between the relationship between relative PPO (W · kg-1) and relative VO2max (ml · min-1 · kg(-1))(p<0.0001), while no gender differences were found between actual and predicted cycling performance based on the Lamberts and Lambert Submaximal Cycle Test (LSCT), which was used a standardized warm-up. In conclusion, relationships between relative cycling parameters seem to differ between genders, while relationships between absolute cycling parameters seem to be similar. Therefore gender specific regression equations should be used when predicting relative cycling performance parameters.

  6. Trabecular bone scales allometrically in mammals and birds.

    PubMed

    Doube, Michael; Klosowski, Michal M; Wiktorowicz-Conroy, Alexis M; Hutchinson, John R; Shefelbine, Sandra J

    2011-10-22

    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.

  7. Allometric scaling and prediction of concentration-time profiles of coagulation factors in humans from animals.

    PubMed

    Mahmood, Iftekhar

    2013-09-01

    Allometric scaling is a useful tool in early drug development and can be used for the prediction of human pharmacokinetic (PK) parameters from animal PK parameters. The main objective of this work was to predict concentration-time profiles of coagulation factors in humans in a multi-compartment system using animal PK parameters. The prediction of concentration-time profiles in humans in a multi-compartment system was based on the predicted values of clearance and volumes of distribution (V(c), V(ss) and V(β)) from animals. Five coagulation factors from the literature were chosen that were described by two-compartment model in both humans and animals. Clearance and volumes of distribution from animals were allometrically scaled to humans and then were used to predict concentration-time profiles in humans. The predicted concentration-time profile for a given coagulation factor was accurate for most of the time points. Percent prediction error range varied across coagulation factors. The prediction error >50% was observed either at 1 or a maximum of two time points for a given drug. The study indicated that the allometric scaling can be useful in the prediction of concentration-time profiles of coagulation factors in humans from animals and may be helpful in designing a first-in-human study.

  8. 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

  9. The origin of allometric scaling laws in biology.

    PubMed

    Demetrius, Lloyd

    2006-12-21

    The empirical rules relating metabolic rate and body size are described in terms of (i) a scaling exponent, which refers to the ratio of the fractional change in metabolic rate to a change in body size, (ii) a proportionality constant, which describes the rate of energy expenditure in an organism of unit mass. This article integrates the chemiosmotic theory of energy transduction with the methods of quantum statistics to propose a molecular mechanism which, in sharp contrast to competing models, explains both the variation in scaling exponents and the taxon-specific differences in proportionality constants. The new model is universal in the sense that it applies to unicellular organisms, plants and animals.

  10. Expression of VO2peak in Children and Youth, with Special Reference to Allometric Scaling.

    PubMed

    Loftin, Mark; Sothern, Melinda; Abe, Takashi; Bonis, Marc

    2016-10-01

    The aim of this review was to highlight research that has focused on examining expressions of peak oxygen uptake (VO2peak) in children and youth, with special reference to allometric scaling. VO2peak is considered the highest VO2 during an increasing workload treadmill or bicycle ergometer test until volitional termination. We have reviewed scholarly works identified from PubMed, One Search, EBSCOhost and Google Scholar that examined VO2peak in absolute units (L·min(-1)), relative units [body mass, fat-free mass (FFM)], and allometric expressions [mass, height, lean body mass (LBM) or LBM of the legs raised to a power function] through July 2015. Often, the objective of measuring VO2peak is to evaluate cardiorespiratory function and fitness level. Since body size (body mass and height) frequently vary greatly in children and youth, expressing VO2peak in dimensionless units is often inappropriate for comparative or explanatory purposes. Consequently, expressing VO2peak in allometric units has gained increased research attention over the past 2 decades. In our review, scaling mass was the most frequent variable employed, with coefficients ranging from approximately 0.30 to over 1.0. The wide variance is probably due to several factors, including mass, height, LBM, sex, age, physical training, and small sample size. In summary, we recommend that since skeletal muscle is paramount for human locomotion, an allometric expression of VO2peak relative to LBM is the best expression of VO2peak in children and youth.

  11. Allometric scaling of the optic tectum in cartilaginous fishes.

    PubMed

    Yopak, Kara E; Lisney, Thomas J

    2012-01-01

    In cartilaginous fishes (Chondrichthyes; sharks, skates and rays (batoids), and holocephalans), the midbrain or mesencephalon can be divided into two parts, the dorsal tectum mesencephali or optic tectum (analogous to the superior colliculus of mammals) and the ventral tegmentum mesencephali. Very little is known about interspecific variation in the relative size and organization of the components of the mesencephalon in these fishes. This study examined the relative development of the optic tectum and the tegmentum in 75 chondrichthyan species representing 32 families. This study also provided a critical assessment of attempts to quantify the size of the optic tectum in these fishes volumetrically using an idealized half-ellipsoid approach (method E), by comparing this method to measurements of the tectum from coronal cross sections (method S). Using species as independent data points and phylogenetically independent contrasts, relationships between the two midbrain structures and both brain and mesencephalon volume were assessed and the relative volume of each brain area (expressed as phylogenetically corrected residuals) was compared among species with different ecological niches (as defined by primary habitat and lifestyle). The relatively largest tecta and tegmenta were found in pelagic coastal/oceanic and oceanic sharks, benthopelagic reef sharks, and benthopelagic coastal sharks. The smallest tecta were found in all benthic sharks and batoids and the majority of bathyal (deep-sea) species. These results were consistent regardless of which method of estimating tectum volume was used. We found a highly significant correlation between optic tectum volume estimates calculated using method E and method S. Taxon-specific variation in the difference between tectum volumes calculated using the two methods appears to reflect variation in both the shape of the optic tectum relative to an idealized half-ellipsoid and the volume of the ventricular cavity. Because the

  12. 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.

  13. A comparison of ratio and allometric scaling methods for normalizing power and strength in elite rugby union players.

    PubMed

    Crewther, Blair T; Gill, Nicholas; Weatherby, Robert P; Lowe, Tim

    2009-12-01

    In this study, we compared the effectiveness of ratio and allometric scaling for normalizing power and strength in elite male rugby union players. Rugby union forwards (n = 18) and backs (n = 20) were assessed for squat jump and bench throw peak power, and box squat and bench press one-repetition maximum strength. The performance data for the forwards and backs were compared using ratio (P/BM) and allometric scaling (P/BM(b)), where P represents performance, BM is body mass in kilograms, and b is a power exponent. A proposed allometric exponent (0.67) and exponents (+/-95% confidence intervals) derived for the box squat (0.33 +/- 0.31), bench press (0.45 +/- 0.30), bench throw (0.46 +/- 0.36), and squat jump (0.64 +/- 0.31) exercises were used. In general, the absolute expression of power and strength was superior for the heavier forwards, but after ratio scaling these performance measures then favoured the lighter backs. There were no performance differences between the forwards and backs after allometric scaling using either the proposed or the derived exponents. Thus, allometric scaling may provide a more effective method for normalizing power and strength in elite athletes when body size is a confounding variable.

  14. 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.

  15. 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.

  16. 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.

  17. Proton leak in hepatocytes and liver mitochondria from archosaurs (crocodiles) and allometric relationships for ectotherms.

    PubMed

    Hulbert, A J; Else, P L; Manolis, S C; Brand, M D

    2002-07-01

    It has previously been shown that mitochondrial proton conductance decreases with increasing body mass in mammals and is lower in a 250-g lizard than the laboratory rat. To examine whether mitochondrial proton conductance is extremely low in very large reptiles, hepatocytes and mitochondria were prepared from saltwater crocodiles ( Crocodylus porosus) and freshwater crocodiles ( Crocodylus johnstoni). Respiration rates of hepatocytes and liver mitochondria were measured at 37 degrees C and compared with values obtained for rat or previously measured for other species. Respiration rates of hepatocytes from either species of crocodile were similar to those reported for lizards and approximately one fifth of the rates measured using cells from mammals (rat and sheep). Ten-to-thirty percent of crocodile hepatocyte respiration was used to drive mitochondrial proton leak, similar to the proportion in other species. Respiration rates of crocodile liver mitochondria were similar to those of mammalian species. Proton leak rate in isolated liver mitochondria was measured as a function of membrane potential. Contrary to our prediction, the mitochondrial proton conductance of liver mitochondria from crocodiles was greater than that of liver mitochondria from lizards and was similar to that of rats. The acyl composition of liver mitochondrial phospholipids from the crocodiles was more similar to that in mitochondria from rats than in mitochondria from lizards. The relatively high mitochondrial proton conductance was associated with a relatively small liver, which seems to be characteristic of crocodilians. Comparison of data from a number of diverse ectothermic species suggested that hepatocyte respiration rate may decrease with body mass, with an allometric exponent of about -0.2, similar to the exponent in mammalian hepatocytes. However, unlike mammals, liver mitochondrial proton conductance in ectotherms showed no allometric relationship with body size.

  18. 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

  19. 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.

  20. Quantitative Trait Loci Affecting Phenotypic Plasticity and the Allometric Relationship of Ovariole Number and Thorax Length in Drosophila melanogaster

    PubMed Central

    Bergland, Alan O.; Genissel, Anne; Nuzhdin, Sergey V.; Tatar, Marc

    2008-01-01

    Environmental factors during juvenile growth such as temperature and nutrition have major effects on adult morphology and life-history traits. In Drosophila melanogaster, ovary size, measured as ovariole number, and body size, measured as thorax length, are developmentally plastic traits with respect to larval nutrition. Herein we investigated the genetic basis for plasticity of ovariole number and body size, as well the genetic basis for their allometric relationship using recombinant inbred lines (RILs) derived from a natural population in Winters, California. We reared 196 RILs in four yeast concentrations and measured ovariole number and body size. The genetic correlation between ovariole number and thorax length was positive, but the strength of this correlation decreased with increasing yeast concentration. Genetic variation and genotype-by-environment (G × E) interactions were observed for both traits. We identified quantitative trait loci (QTL), epistatic, QTL-by-environment, and epistatic-by-environment interactions for both traits and their scaling relationships. The results are discussed in the context of multivariate trait evolution. PMID:18716336

  1. 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.

  2. Allometric scaling of decompression sickness risk in terrestrial mammals; cardiac output explains risk of decompression sickness

    NASA Astrophysics Data System (ADS)

    Fahlman, Andreas

    2017-02-01

    A probabilistic model was used to predict decompression sickness (DCS) outcome in pig (70 and 20 kg), hamster (100 g), rat (220 g) and mouse (20 g) following air saturation dives. The data set included 179 pig, 200 hamster, 360 rat, and 224 mouse exposures to saturation pressures ranging from 1.9–15.2 ATA and with varying decompression rates (0.9–156 ATA • min‑1). Single exponential kinetics described the tissue partial pressures (Ptiss) of N2: Ptiss =  ∫(Pamb – Ptiss) • τ‑1 dt, where Pamb is ambient N2 pressure and τ is a time constant. The probability of DCS [P(DCS)] was predicted from the risk function: P(DCS) = 1‑e‑r, where r = ∫(PtissN2 ‑ Thr ‑ Pamb) • Pamb–1 dt, and Thr is a threshold parameter. An equation that scaled τ with body mass included a constant (c) and an allometric scaling parameter (n), and the best model included n, Thr, and two c. The final model provided accurate predictions for 58 out of 61 dive profiles for pig, hamster, rat, and mouse. Thus, body mass helped improve the prediction of DCS risk in four mammalian species over a body mass range covering 3 orders of magnitude.

  3. Allometric scaling of decompression sickness risk in terrestrial mammals; cardiac output explains risk of decompression sickness

    PubMed Central

    Fahlman, Andreas

    2017-01-01

    A probabilistic model was used to predict decompression sickness (DCS) outcome in pig (70 and 20 kg), hamster (100 g), rat (220 g) and mouse (20 g) following air saturation dives. The data set included 179 pig, 200 hamster, 360 rat, and 224 mouse exposures to saturation pressures ranging from 1.9–15.2 ATA and with varying decompression rates (0.9–156 ATA • min−1). Single exponential kinetics described the tissue partial pressures (Ptiss) of N2: Ptiss =  ∫(Pamb – Ptiss) • τ−1 dt, where Pamb is ambient N2 pressure and τ is a time constant. The probability of DCS [P(DCS)] was predicted from the risk function: P(DCS) = 1−e−r, where r = ∫(PtissN2 − Thr − Pamb) • Pamb–1 dt, and Thr is a threshold parameter. An equation that scaled τ with body mass included a constant (c) and an allometric scaling parameter (n), and the best model included n, Thr, and two c. The final model provided accurate predictions for 58 out of 61 dive profiles for pig, hamster, rat, and mouse. Thus, body mass helped improve the prediction of DCS risk in four mammalian species over a body mass range covering 3 orders of magnitude. PMID:28150725

  4. Allometric scaling of decompression sickness risk in terrestrial mammals; cardiac output explains risk of decompression sickness.

    PubMed

    Fahlman, Andreas

    2017-02-02

    A probabilistic model was used to predict decompression sickness (DCS) outcome in pig (70 and 20 kg), hamster (100 g), rat (220 g) and mouse (20 g) following air saturation dives. The data set included 179 pig, 200 hamster, 360 rat, and 224 mouse exposures to saturation pressures ranging from 1.9-15.2 ATA and with varying decompression rates (0.9-156 ATA • min(-1)). Single exponential kinetics described the tissue partial pressures (Ptiss) of N2: Ptiss =  ∫(Pamb - Ptiss) • τ(-1) dt, where Pamb is ambient N2 pressure and τ is a time constant. The probability of DCS [P(DCS)] was predicted from the risk function: P(DCS) = 1-e(-r), where r = ∫(PtissN2 - Thr - Pamb) • Pamb(-1) dt, and Thr is a threshold parameter. An equation that scaled τ with body mass included a constant (c) and an allometric scaling parameter (n), and the best model included n, Thr, and two c. The final model provided accurate predictions for 58 out of 61 dive profiles for pig, hamster, rat, and mouse. Thus, body mass helped improve the prediction of DCS risk in four mammalian species over a body mass range covering 3 orders of magnitude.

  5. Appropriate interpretation of aerobic capacity: allometric scaling in adult and young soccer players

    PubMed Central

    Chamari, K; Moussa-Chamari, I; Boussaidi, L; Hachana, Y; Kaouech, F; Wisloff, U

    2005-01-01

    Objective: To compare aerobic capacity of young and adult elite soccer players using appropriate scaling procedures. Methods: Twenty four male adult (mean (SD) age 24 (2) years, weight 75.7 (7.2) kg, VO2MAX 66.6 (5.2) ml/lbm/min, where lbm is lean body mass in kg) and 21 youth (14 (0.4) years, 60.2 (7.3) kg, 66.5 (5.9) ml/lbm/min) elite soccer players took part in the study. Allometric equations were used to determine the relation between maximal and submaximal oxygen cost of running (running economy) and body mass. Results: Maximal and submaximal oxygen uptake increased in proportion to body mass raised to the power of 0.72 (0.04) and 0.60 (0.06) respectively. The VO2MAX of adult players was similar to that of the youth players when expressed in direct proportion to body mass—that is, ml/kg/min—but 5% higher (p<0.05) when expressed using appropriate procedures for scaling. Conversely, compared with seniors, youth players had 13% higher (p<0.001) energy cost of running—that is, poorer running economy—when expressed as ml/kg/min but not when expressed according to the scaling procedures. Conclusions: Compared with the youth soccer players, VO2MAX in the seniors was underestimated and running economy overestimated when expressed traditionally as ml/lbm/min. The study clearly shows the pitfalls in previous studies when aerobic capacity was evaluated in subjects with different body mass. It further shows that the use of scaling procedures can affect the evaluation of, and the resultant training programme to improve, aerobic capacity. PMID:15665205

  6. 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...

  7. Allometric scaling in the dentition of primates and prediction of body weight from tooth size in fossils.

    PubMed

    Gingerich, P D; Smith, B H; Rosenberg, K

    1982-05-01

    Tooth size varies exponentially with body weight in primates. Logarithmic transformation of tooth crown area and body weight yields a linear model of slope 0.67 as an isometric (geometric) baseline for study of dental allometry. This model is compared with that predicted by metabolic scaling (slope = 0.75). Tarsius and other insectivores have larger teeth for their body size than generalized primates do and they are not included in this analysis. Among generalized primates, tooth size is highly correlated with body size. Correlations of upper and lower cheek teeth with body size range from 0.90-0.97, depending on tooth position. Central cheek teeth (P44 and M11) have allometric coefficients ranging from 0.57-0.65, falling well below geometric scaling. Anterior and posterior cheek teeth scale at or above metabolic scaling. Considered individually or as a group, upper cheek teeth scale allometrically with lower coefficients than corresponding lower cheek teeth; the reverse is true for incisors. The sum of crown areas for all upper cheek teeth scales significantly below geometric scaling, while the sum of crown areas for all lower cheek teeth approximates geometric scaling. Tooth size can be used to predict the body weight of generalized fossil primates. This is illustrated for Aegyptopithecus and other Eocene, Oligocene, and miocene primates. Regressions based on tooth size in generalized primates yield reasonable estimates of body weight, but much remains to be learned about tooth size and body size scaling in more restricted systematic groups and dietary guilds.

  8. 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

  9. Jellyfish body plans provide allometric advantages beyond low carbon content.

    PubMed

    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

  10. Differentiating causality and correlation in allometric scaling: ant colony size drives metabolic hypometry.

    PubMed

    Waters, James S; Ochs, Alison; Fewell, Jennifer H; Harrison, Jon F

    2017-02-22

    Metabolic rates of individual animals and social insect colonies generally scale hypometrically, with mass-specific metabolic rates decreasing with increasing size. Although this allometry has wide ranging effects on social behaviour, ecology and evolution, its causes remain controversial. Because it is difficult to experimentally manipulate body size of organisms, most studies of metabolic scaling depend on correlative data, limiting their ability to determine causation. To overcome this limitation, we experimentally reduced the size of harvester ant colonies (Pogonomyrmex californicus) and quantified the consequent increase in mass-specific metabolic rates. Our results clearly demonstrate a causal relationship between colony size and hypometric changes in metabolic rate that could not be explained by changes in physical density. These findings provide evidence against prominent models arguing that the hypometric scaling of metabolic rate is primarily driven by constraints on resource delivery or surface area/volume ratios, because colonies were provided with excess food and colony size does not affect individual oxygen or nutrient transport. We found that larger colonies had lower median walking speeds and relatively more stationary ants and including walking speed as a variable in the mass-scaling allometry greatly reduced the amount of residual variation in the model, reinforcing the role of behaviour in metabolic allometry. Following the experimental size reduction, however, the proportion of stationary ants increased, demonstrating that variation in locomotory activity cannot solely explain hypometric scaling of metabolic rates in these colonies. Based on prior studies of this species, the increase in metabolic rate in size-reduced colonies could be due to increased anabolic processes associated with brood care and colony growth.

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

    PubMed

    Ryan, Timothy M; Shaw, Colin N

    2013-05-07

    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.

  12. 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

  13. Predicting maximum tree heights and other traits from allometric scaling and resource limitations.

    PubMed

    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.

  14. Species-specific allometric scaling under self-thinning: evidence from long-term plots in forest stands.

    PubMed

    Pretzsch, Hans

    2006-01-01

    Experimental plots covering a 120 years' observation period in unthinned, even-aged pure stands of common beech (Fagus sylvatica), Norway spruce (Picea abies), Scots pine (Pinus sylvestris), and common oak (Quercus Petraea) are used to scrutinize Reineke's (1933) empirically derived stand density rule [see text], N=tree number per unit area, [see text]=mean stem diameter), Yoda's (1963) self-thinning law based on Euclidian geometry ([see text] [see text]=mean biomass per tree), and basic assumptions of West, Brown and Enquist's (1997, 1999) fractal scaling rules ([see text] [see text] w=biomass per tree, d=stem diameter). RMA and OLS regression provides observed allometric exponents, which are tested against the exponents, expected by the considered rules. Hope for a consistent scaling law fades away, as observed exponents significantly correspond with the considered rules only in a minority of cases: (1) exponent r of [see text] varies around Reineke's constant -1.605, but is significantly different from r=-2, supposed by Euclidian or fractal scaling, (2) Exponent c of the self-thinning line [see text] roams roughly about the Euclidian scaling constant -3/2, (3) Exponent a of [see text] tends to follow fractal scaling 8/3. The unique dataset's evaluation displays that (4) scaling exponents and their oscillation are species-specific, (5) Euclidian scaling of one relation and fractal scaling of another are coupled, depending on species. Ecological implications of the results in respect to self-tolerance (common oak>Norway spruce>Scots pine>common beech) and efficiency of space occupation (common beech>Scots pine>Norway spruce>common oak) are stressed and severe consequences for assessing, regulating and scheduling stand density are discussed.

  15. 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.

  16. 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.

  17. The fourth dimension of life: fractal geometry and allometric scaling of organisms.

    PubMed

    West, G B; Brown, J H; Enquist, B J

    1999-06-04

    Fractal-like networks effectively endow life with an additional fourth spatial dimension. This is the origin of quarter-power scaling that is so pervasive in biology. Organisms have evolved hierarchical branching networks that terminate in size-invariant units, such as capillaries, leaves, mitochondria, and oxidase molecules. Natural selection has tended to maximize both metabolic capacity, by maximizing the scaling of exchange surface areas, and internal efficiency, by minimizing the scaling of transport distances and times. These design principles are independent of detailed dynamics and explicit models and should apply to virtually all organisms.

  18. 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

  19. Allometric scaling of long-distance seed dispersal by migratory birds.

    PubMed

    Viana, Duarte S; Santamaría, Luis; Michot, Thomas C; Figuerola, Jordi

    2013-05-01

    Migratory birds are often suggested to be important vectors for long-distance dispersal (LDD) of plant and animal propagules. The scale of such dispersal events (hundreds to thousands of kilometers) can influence landscape-level biological processes and species distributions. However, the few vector species studied and the lack of proper integration of their migratory movement in models of LDD has precluded the study of their potential as long-distance biotic dispersers. By means of a mechanistic model parameterized with empirical data, we first investigated the properties of seed dispersal curves generated by migratory birds and then analyzed the effect of bird size on model parameters and consequent seed dispersal patterns. Seed dispersal curves showed in most cases large and heavy tails, resulting in relatively frequent LDD (up to 3.5% of dispersal distances longer than 100 km). Bird size mediated trade-offs between bird movement and seed retention time that, in turn, determined seed dispersal patterns and the potential of each bird species as an LDD vector. Our modeling framework builds on a mechanistic understanding of seed dispersal by migratory birds and may thus be a useful tool to estimate the scale and frequency of bird-mediated, large-scale transport of native, invasive, and pathogenic organisms.

  20. Soil acidity, ecological stoichiometry and allometric scaling in grassland food webs

    PubMed Central

    MULDER, CHRISTIAN; ELSER, JAMES J

    2009-01-01

    The factors regulating the structure of food webs are a central focus of community and ecosystem ecology, as trophic interactions among species have important impacts on nutrient storage and cycling in many ecosystems. For soil invertebrates in grassland ecosystems in the Netherlands, the site-specific slopes of the faunal biomass to organism body mass relationships reflected basic biochemical and biogeochemical processes associated with soil acidity and soil C : N : P stoichiometry. That is, the higher the phosphorus availability in the soil, the higher, on average, the slope of the faunal biomass size spectrum (i.e., the higher the biomass of large-bodied invertebrates relative to the biomass of small invertebrates). While other factors may also be involved, these results are consistent with the growth rate hypothesis from biological stoichiometry that relates phosphorus demands to ribosomal RNA and protein production. Thus our data represent the first time that ecosystem phosphorus availability has been associated with allometry in soil food webs (supporting information available online). Our results have broad implications, as soil invertebrates of different size have different effects on soil processes.

  1. Integrated pharmacokinetic-pharmacodynamic modeling and allometric scaling for optimizing the dosage regimen of the monoclonal ior EGF/r3 antibody.

    PubMed

    Duconge, Jorge; Castillo, Rubén; Crombet, Tania; Alvarez, Daniel; Matheu, Janet; Vecino, Gloria; Alonso, Katia; Beausoleil, Irene; Valenzuela, Carmen; Becquer, Maria A; Fernández-Sánchez, Eduardo

    2004-02-01

    The multiple-dose strategy with the monoclonal ior EGF/r3 antibody, in xenograft bearing nude mice, was supported upon the basis of its integrated pharmacokinetic-pharmacodynamic relationship, according to both the temporal (K(e0)=0.0015+/-0.000035h(-1)) and the time-independent sensitivity (C(50%)(ss), 9.23+/-0.17microg/ml; C(max,eff)(ss), 12.5microg/ml) components of its tumor growth delay action. This relationship was consistent with a sigmoidal E(max) pharmacodynamic model postulating a hypothetical effect compartment that permits us to estimate an effective steady-state concentration range (7.5-12microg/ml). Using this information we calculated both the cumulative and non-cumulative dosage regimens to compare their response patterns with respect to the control group. It follows that the differences in the estimated tumor growth inhibition ratio were statistically significant between the control group and either of the treated ones (P<0.05). The median survival time in treated mice under non-cumulative regimen (72+/-10 days), predicted an increase in this parameter as compared to the control one (55+/-6 days). Finally, using the allometric paradigm, the empiric power equation for dose scaling across mammalian species allowed the calculation of the dosage schedule for further clinical trial. The estimated maintenance dose in human (70kg) was 200mg/m(2) to be given weekly, and the corresponding loading dose was 600mg/m(2).

  2. Interspecies allometric scaling.

    PubMed

    Hunter, Robert P

    2010-01-01

    Lack of approved pharmaceutical agents and very limited pharmacokinetic data in the scientific literature for exotic, wildlife, and zoo species are a major issue for veterinarians treating these species. There are fewer than 15 compounds approved in the United States for zoo and wildlife species compared to nearly 300 drugs licensed for cattle. Zoo veterinarians are therefore required to extrapolate the use of approved agents (veterinary or human) to nonapproved species, often with little or no scientific basis to support drug or dose schedule selection. In general, species differences in drug absorption, metabolism, distribution, and excretion have been well documented for domestic species. However, there has been limited research to provide similar data for nondomestic species. Consequently, with the possible exception of pet bird species, there is little published information on the pharmacokinetic parameters of drugs in nondomestic species. Additionally, because of the commercial value of many zoo species, the traditional method of "trial and error" for drug and dose selection and related compliance issues is often inappropriate. There is an understandable concern, whereby the zoo veterinarian does not wish to be the first to administer an agent or formulation in an untested species. "One medicine" is a central concept in treating zoo species, in that vertebrate species are generally more similar than dissimilar. However, drug absorption can vary within as well as between species. Considering the anatomical differences between true monogastrics (canine and feline species), hind-gut fermentors (rodents, rabbits, horses, and elephants), fore-gut fermentors (Colobus monkeys and kangaroos), and ruminants (cattle, goats, sheep, and antelope), the potential for differences in pharmacokinetic profiles are marked. Moreover, there are potential differences between organisms in a single class. An example is the ability of several snake species to up- and down-regulate their digestive systems. This renders the time course of oral drug absorption dependent on both body temperature and time after feeding. Plasma protein binding may vary considerably between species and may also be temperature dependent. This is very significant when treating poikilothermic (reptiles, amphibians, and fish) species and when conducting pharmacokinetic studies with highly protein-bound drugs. The large body sizes of some zoo species create additional considerations for treatment with drugs and can place significant limitations on delivery of an effective drug dose.

  3. Calculation of a First-In-Man Dose of 7-O-Succinyl Macrolactin A Based on Allometric Scaling of Data from Mice, Rats, and Dogs.

    PubMed

    Noh, Keumhan; Kang, Wonku

    2017-03-10

    7-O-succinyl macrolactin A (SMA) exerts several pharmacological effects including anti-bacterial, anti-inflammation, and anticancer activities. Recently, SMA has been extensively evaluated as an anti-cancer drug. Thus, the objectives of the present study were to characterise the pharmacokinetics of SMA via both non-compartmental and compartmental analysis in mice, rats, and dogs, and to derive an appropriate first-in-man dose based on allometric scaling of the animal data. The time courses of plasma SMA concentrations after intravenous administration to rats and dogs were analysed retrospectively, as were data collected after intraperitoneal SMA injection in mice. Pharmacokinetic parameters were estimated via both noncompartmental and compartmental analysis, and were correlated with body weight and/or the potential maximum life-span. The clearance and distribution volume of SMA in humans were predicted, and a first-in-man dose proposed. A two-compartment model best described the time courses of SMA plasma concentrations after a saturation elimination process was applied to fit the dataset obtained from rats. Incorporation of the maximum potential life-span during allometric scaling was required to improve the estimation of human clearance. The SMA clearance and the distribution volume in the steady state, in a 70-kg adult male, were estimated to be 30.6 L/h and 19.5 L, respectively. To meet the area under the curve (AUC) required for anti-tumour activity, a dose of 100 mg (~1.5 mg/kg) was finally proposed as the first dose for a 70-kg human. Although toxicological profiles derived from non-clinical studies must be considered before any final decision is made, our work will facilitate clinical studies on SMA.

  4. Absolute and allometric relationships between internal morphology and body mass in the adult collared peccary, Tayassu tajacu (Tayassuidae).

    PubMed

    Lochmiller, R L; Hellgren, E C; Grant, W E

    1986-01-01

    Selected morphological features of 8 adult male and 8 adult female collared peccaries (Tayassu tajacu) shot from southern Texas during March 1983 are described. A total of 16 adult peccaries with an average body mass of 18.68 +/- 0.61 (SE) Kg was examined. Significant differences between males and females were observed for absolute and relative mass of liver and lungs, and relative heart mass. These visceral organs were heavier among females than males. Significant sex effects were also found for absolute and relative mass of the dorsal scent gland. The dorsal scent gland contributed twice as much to total body mass in males as in females. No sexual dimorphisms of the gastrointestinal tract were noted. Females had a significantly greater portion of total visceral fat deposited around the kidneys than did males. Relative mass of the mandible was significantly greater in males than in females. Adult males had extremely large accessory sex glands. The bulbourethral and seminal vesicle glands comprised 0.27 per cent of the total body mass. Allometric growth coefficients (b) varied among the various organs and glands examined, ranging from below (eyes, b = 0.34) to well above (seminal vesicles, b = 1.87) unity. Growth coefficients of lungs, kidneys, pituitary gland, and thyroid gland during adulthood greatly exceeded respective values in developing nurslings.

  5. Allometric space and allometric disparity: a developmental perspective in the macroevolutionary analysis of morphological disparity.

    PubMed

    Gerber, Sylvain; Eble, Gunther J; Neige, Pascal

    2008-06-01

    Here, we advance novel uses of allometric spaces--multidimensional spaces specifically defined by allometric coefficients--with the goal of investigating the focal role of development in shaping the evolution of morphological disparity. From their examination, operational measures of allometric disparity can be derived, complementing standard signals of morphological disparity through an intuitive and process-oriented refinement of established analytical protocols used in disparity studies. Allometric spaces thereby become a promising context to reveal different patterns of evolutionary developmental changes and to assess their relative prevalence and importance. Such spaces offer a novel domain of investigation of phenotypic variation and should help in detecting large-scale trends, thus placing various macroevolutionary phenomena in an explicitly developmental context. Ammonoidea (Cephalopoda) at the Lower-Middle Jurassic transition were chosen as a case study to illustrate this methodological approach. We constructed two phenotypic spaces: a static, adult one (adult morphospace) and a dynamic, developmental one (allometric space). Comparative disparity analyses show a strikingly stable occupation in both spaces, despite extensive change in taxonomic composition. In contrast, disparity analyses of subclades reveal clearly distinct morphological and allometric disparity dynamics. Allometric approaches allow developmental insights into morphological diversification otherwise intractable from the analysis of adult morphospace alone.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. A novel in vitro allometric scaling methodology for aldehyde oxidase substrates to enable selection of appropriate species for traditional allometry.

    PubMed

    Crouch, Rachel D; Hutzler, J Matthew; Daniels, J Scott

    2017-03-10

    1. Failure to predict human pharmacokinetics of aldehyde oxidase (AO) substrates using traditional allometry has been attributed to species differences in AO metabolism. 2. To identify appropriate species for predicting human in vivo clearance by single-species scaling (SSS) or multispecies allometry (MA), we scaled in vitro intrinsic clearance (CLint) of five AO substrates obtained from hepatic S9 of mouse, rat, guinea pig, monkey and minipig to human in vitro CLint. 3. When predicting human in vitro CLint, average absolute fold-error was ≤2.0 by SSS with monkey, minipig and guinea pig (rat/mouse >3.0) and was <3.0 by most MA species combinations (including rat/mouse combinations). 4. Interspecies variables, including fraction metabolized by AO (Fm,AO) and hepatic extraction ratios (E) were estimated in vitro. SSS prediction fold-errors correlated with the animal:human ratio of E (r(2) = 0.6488), but not Fm,AO (r(2) = 0.0051). 5. Using plasma clearance (CLp) from the literature, SSS with monkey was superior to rat or mouse at predicting human CLp of BIBX1382 and zoniporide, consistent with in vitro SSS assessments. 6. Evaluation of in vitro allometry, Fm,AO and E may prove useful to guide selection of suitable species for traditional allometry and prediction of human pharmacokinetics of AO substrates.

  11. Allometric disparity in rodent evolution

    PubMed Central

    Wilson, Laura A B

    2013-01-01

    In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

  12. Allometric growth in reef-building corals.

    PubMed

    Dornelas, Maria; Madin, Joshua S; Baird, Andrew H; Connolly, Sean R

    2017-03-29

    Predicting demographic rates is a critical part of forecasting the future of ecosystems under global change. Here, we test if growth rates can be predicted from morphological traits for a highly diverse group of colonial symbiotic organisms: scleractinian corals. We ask whether growth is isometric or allometric among corals, and whether most variation in coral growth rates occurs at the level of the species or morphological group. We estimate growth as change in planar area for 11 species, across five morphological groups and over 5 years. We show that coral growth rates are best predicted from colony size and morphology rather than species. Coral size follows a power scaling law with a constant exponent of 0.91. Despite being colonial organisms, corals have consistent allometric scaling in growth. This consistency simplifies the task of projecting community responses to disturbance and climate change.

  13. 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

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

    PubMed

    Duncanson, L; Rourke, O; Dubayah, R

    2015-11-24

    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.

  15. 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.

  16. Body and limb size dissociation at the origin of birds: uncoupling allometric constraints across a macroevolutionary transition.

    PubMed

    Dececchi, T Alexander; Larsson, Hans C E

    2013-09-01

    The origin of birds and powered flight is a classic major evolutionary transition. Research on their origin often focuses on the evolution of the wing with trends of forelimb elongation traced back through many nonavian maniraptoran dinosaurs. We present evidence that the relative forelimb elongation within avian antecedents is primarily due to allometry and is instead driven by a reduction in body size. Once body size is factored out, there is no trend of increasing forelimb length until the origin of birds. We report that early birds and nonavian theropods have significantly different scaling relationships within the forelimb and hindlimb skeleton. Ancestral forelimb and hindlimb allometric scaling to body size is rapidly decoupled at the origin of birds, when wings significantly elongate, by evolving a positive allometric relationship with body size from an ancestrally negative allometric pattern and legs significantly shorten by keeping a similar, near isometric relationship but with a reduced intercept. These results have implications for the evolution of powered flight and early diversification of birds. They suggest that their limb lengths first had to be dissociated from general body size scaling before expanding to the wide range of fore and hindlimb shapes and sizes present in today's birds.

  17. Coarser wool is not a necessary consequence of sheep aging: allometric relationship between fibre diameter and fleece-free liveweight of Saxon Merino sheep.

    PubMed

    McGregor, B A; Butler, K L

    2016-12-01

    The mean fibre diameter (MFD) of wool is the primary determinant of price, processing performance and textile quality. This study determines the primary influences on MFD as Saxon Merino sheep age, by allometrically relating MFD to fleece-free liveweight (FFLwt). In total, 79 sheep were grazed in combinations of three stocking rates and two grazing systems (GS: sheep only; mixed with Angora goats) and studied over 3 years. Measurements were made over 14 consecutive periods (Segments), including segments of FFLwt gain or FFLwt loss. Using shearing and liveweight records and dye-bands on wool, the FFLwt and average daily gain (ADG) of each sheep were determined for each segment. The mean and range in key measurements were as follows: FFLwt, 40.1 (23.1 to 64.1) kg; MFD, 18.8 (12.7 to 25.8) μm. A random coefficient restricted maximum likelihood (REML) regression mixed model was developed to relate the logarithm of MFD to the logarithm of FFLwt and other effects. The model can be written in the form of ${\\rm MFD}\\,{\\equals}\\,\\rkappa \\left( {{\\rm GS,}\\,{\\rm A}{\\rm ,}\\,{\\rm Segment}{\\rm .Plot,}\\,{\\rm Segment,}\\,{\\rm ADG}} \\right){\\times}{\\rm FFLwt}^{{\\left( {\\ralpha \\left( {{\\rm GS}} \\right){\\plus}\\rbeta \\left(\\rm A \\right){\\plus}\\rgamma \\left( {{\\rm Segment}{\\rm .Plot}} \\right)} \\right)}} $ , where $\\ralpha \\left( {{\\rm GS}} \\right)\\,{\\equals}\\,\\;\\left\\{ {\\matrix{\\!\\! {0.32\\left( {{\\rm SE}\\,{\\equals}\\,{\\rm 0}{\\rm .038}} \\right)\\,{\\rm when}\\,{\\rm sheep}\\,{\\rm are}\\,{\\rm grazed}\\,{\\rm alone}} \\hfill \\cr \\!\\!\\!\\!{0.49\\left( {{\\rm SE}\\,{\\equals}\\,{\\rm 0}{\\rm .049}} \\right)\\,{\\rm when}\\,{\\rm sheep}\\,{\\rm are}\\,{\\rm mixed}\\,{\\rm with}\\,{\\rm goats}} \\hfill \\cr } } \\right.$ β(A) is a random animal effect, γ(Segment.Plot) a random effect associated with Segment.plot combinations, and κ a constant that depends on GS, random animal effects, random Segment.plot combination effects

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

    PubMed Central

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

    2016-01-01

    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. SIGNIFICANCE STATEMENT Sex and sex-chromosome dosage (SCD) are known to modulate human brain size and cortical anatomy, but very little is known regarding their impact on subcortical structures that work with the cortex to subserve a range of behaviors in health and disease. Moreover

  19. Pharmacokinetic Modeling of Paracetamol Uptake and Clearance in Zebrafish Larvae: Expanding the Allometric Scale in Vertebrates with Five Orders of Magnitude

    PubMed Central

    Kantae, Vasudev; Krekels, Elke H.J.; Ordas, Anita; González, Oskar; van Wijk, Rob C.; Harms, Amy C.; Racz, Peter I.; van der Graaf, Piet H.; Spaink, Herman P.

    2016-01-01

    Abstract Zebrafish larvae (Danio rerio) are increasingly used to translate findings regarding drug efficacy and safety from in vitro-based assays to vertebrate species, including humans. However, the limited understanding of drug exposure in this species hampers its implementation in translational research. Using paracetamol as a paradigm compound, we present a novel method to characterize pharmacokinetic processes in zebrafish larvae, by combining sensitive bioanalytical methods and nonlinear mixed effects modeling. The developed method allowed quantification of paracetamol and its two major metabolites, paracetamol-sulfate and paracetamol-glucuronide in pooled samples of five lysed zebrafish larvae of 3 days post-fertilization. Paracetamol drug uptake was quantified to be 0.289 pmole/min and paracetamol clearance was quantified to be 1.7% of the total value of the larvae. With an average volume determined to be 0.290 μL, this yields an absolute clearance of 2.96 × 107 L/h, which scales reasonably well with clearance rates in higher vertebrates. The developed methodology will improve the success rate of drug screens in zebrafish larvae and the translation potential of findings, by allowing the establishment of accurate exposure profiles and thereby also the establishment of concentration–effect relationships. PMID:27632065

  20. Cryptic individual scaling relationships and the evolution of morphological scaling.

    PubMed

    Dreyer, Austin P; Saleh Ziabari, Omid; Swanson, Eli M; Chawla, Akshita; Frankino, W Anthony; Shingleton, Alexander W

    2016-08-01

    Morphological scaling relationships between organ and body size-also known as allometries-describe the shape of a species, and the evolution of such scaling relationships is central to the generation of morphological diversity. Despite extensive modeling and empirical tests, however, the modes of selection that generate changes in scaling remain largely unknown. Here, we mathematically model the evolution of the group-level scaling as an emergent property of individual-level variation in the developmental mechanisms that regulate trait and body size. We show that these mechanisms generate a "cryptic individual scaling relationship" unique to each genotype in a population, which determines body and trait size expressed by each individual, depending on developmental nutrition. We find that populations may have identical population-level allometries but very different underlying patterns of cryptic individual scaling relationships. Consequently, two populations with apparently the same morphological scaling relationship may respond very differently to the same form of selection. By focusing on the developmental mechanisms that regulate trait size and the patterns of cryptic individual scaling relationships they produce, our approach reveals the forms of selection that should be most effective in altering morphological scaling, and directs researcher attention on the actual, hitherto overlooked, targets of selection.

  1. Validation of the Interpersonal Relationship Rating Scale.

    ERIC Educational Resources Information Center

    Brown, Nina W.; Sullivan, James

    1979-01-01

    Hipple's Interpersonal Relationship Rating Scale (1972) was administered to graduate students in a counselor education program. The results were factor analyzed and six scales were extracted. The IRRS was then administered to two classes of students in group counseling. Both groups had significant discrepancy scores. (Author)

  2. Simple Scaling Relationships For Stellar Dynamos

    NASA Astrophysics Data System (ADS)

    Augustson, Kyle; Mathis, Stéphane; Brun, Allan Sacha

    2016-12-01

    This paper provides a brief overview of dynamo scaling relationships for the degree of equipartition between magnetic and kinetic energies. Three basic approaches are adopted to explore these scaling relationships, with a first look at two simple models: one assuming magnetostrophy and another that includes the effects of inertia. Next, a third scaling relationship is derived that utilizes the assumptions that the dynamo possesses two integral spatial scales and that it is driven by the balance of buoyancy work and ohmic dissipation as studied in Davidson 2013. The results of which are then compared to a suite of convective dynamo simulations that possess a fully convective domain with a weak density stratification and that captured the behavior of the resulting dynamo for a range of convective Rossby numbers (Augustson et al. 2016).

  3. Applying Individual Tree Structure From Lidar to Address the Sensitivity of Allometric Equations to Small Sample Sizes.

    NASA Astrophysics Data System (ADS)

    Duncanson, L.; Dubayah, R.

    2015-12-01

    Lidar remote sensing is widely applied for mapping forest carbon stocks, and technological advances have improved our ability to capture structural details from forests, even resolving individual trees. Despite these advancements, the accuracy of forest aboveground biomass models remains limited by the quality of field estimates of biomass. The accuracies of field estimates are inherently dependent on the accuracy of the allometric equations used to relate measurable attributes to biomass. These equations are calibrated with relatively small samples of often spatially clustered trees. This research focuses on one of many issues involving allometric equations - understanding how sensitive allometric parameters are to the sample sizes used to fit them. We capitalize on recent advances in lidar remote sensing to extract individual tree structural information from six high-resolution airborne lidar datasets in the United States. We remotely measure millions of tree heights and crown radii, and fit allometric equations to the relationship between tree height and radius at a 'population' level, in each site. We then extract samples from our tree database, and build allometries on these smaller samples of trees, with varying sample sizes. We show that for the allometric relationship between tree height and crown radius, small sample sizes produce biased allometric equations that overestimate height for a given crown radius. We extend this analysis using translations from the literature to address potential implications for biomass, showing that site-level biomass may be greatly overestimated when applying allometric equations developed with the typically small sample sizes used in popular allometric equations for biomass.

  4. 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

  5. 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…

  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.

  7. Mechanisms driving carbon allocation in tropical rainforests: allometric constraints and environmental responses

    NASA Astrophysics Data System (ADS)

    Hofhansl, Florian; Schnecker, Jörg; Singer, Gabriel; Wanek, Wolfgang

    2014-05-01

    Tropical forest ecosystems play a major role in global water and carbon cycles. However, mechanisms of C allocation in tropical forests and their response to environmental variation are largely unresolved as, due to the scarcity of data, they are underrepresented in global syntheses of forest C allocation. Allocation of gross primary production to wood production exerts a key control on forest C residence time and biomass C turnover, and therefore is of special interest for terrestrial ecosystem research and earth system science. Here, we synthesize pantropical data from 105 old-growth rainforests to investigate relationships between climate (mean annual precipitation, mean annual temperature, dry season length and cloud cover), soil nutrient relations (soil N:P) and the partitioning of aboveground net primary production (ANPP) to wood production (WPart) using structural equation modelling. Our results show a strong increase of WPart with ANPP, pointing towards allometric scaling controls on WPart, with increasing light competition in more productive forests triggering greater ANPP allocation to wood production. ANPP itself was positively affected by mean annual temperature and soil N:P. Beyond these allometric controls on WPart we found direct environmental controls. WPart increased with dry season length in tropical montane rainforests and with mean annual precipitation in lowland tropical rainforests. We discuss different trade-offs between plant traits, such as community-wide changes along the wood economics spectrum, the leaf economics spectrum and the plant resource economics spectrum, as underlying mechanisms for direct climatic controls on WPart. We thereby provide new insights into mechanisms driving carbon allocation to WPart in tropical rainforests and show that low and high productive tropical rainforests may respond differently to projected global changes.

  8. 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.

  9. 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.

  10. 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.

  11. Evaluating general allometric models: interspecific and intraspecific data tell different stories due to interspecific variation in stem tissue density and leaf size.

    PubMed

    Huang, Yingxin; Lechowicz, Martin J; Zhou, Daowei; Price, Charles A

    2016-03-01

    The ability of general scaling models to capture the central tendency or dispersion in biological data has been questioned. In fact, the appropriate domain of such models has never been clearly articulated and they have been supported and challenged using both interspecific and/or intraspecific data. Here, we evaluate several simplifying assumptions and predictions of two prominent scaling models: West, Brown and Enquist's fractal model (WBE) and a null model of geometric similarity (GEOM). Using data for 53 herbaceous angiosperm species from the Songnen Grasslands of Northern China, we compared both the interspecific and intraspecific scaling relationships for plant geometry and biomass partitioning. Specifically, we considered biomass investment in shoots and leaves as well as related several traits not commonly collected in plant allometric analyses: shoot volume, leaf number, and mean leaf mass. At the interspecific level, we find substantial variation in regression slopes, and the simplifying assumptions of WBE and predictions of both the WBE and GEOM models do not hold. In contrast, we find substantial support for the WBE model at the intraspecific level, and to a lesser extent for GEOM. The differences between our results at interspecific and intraspecific levels are due to the fact that leaf size and stem tissue density vary considerably across species in contrast to the simplifying assumptions of WBE. These results highlight the domain within which simplifying model assumptions might be most appropriate, and suggest allometric models may be useful points of departure within some species, growth forms or taxonomic groups.

  12. 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…

  13. 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

  14. Allometric Trajectories and "Stress": A Quantitative Approach.

    PubMed

    Anfodillo, Tommaso; Petit, Giai; Sterck, Frank; Lechthaler, Silvia; Olson, Mark E

    2016-01-01

    The term "stress" is an important but vague term in plant biology. We show situations in which thinking in terms of "stress" is profitably replaced by quantifying distance from functionally optimal scaling relationships between plant parts. These relationships include, for example, the often-cited one between leaf area and sapwood area, which presumably reflects mutual dependence between sources and sink tissues and which scales positively within individuals and across species. These relationships seem to be so basic to plant functioning that they are favored by selection across nearly all plant lineages. Within a species or population, individuals that are far from the common scaling patterns are thus expected to perform negatively. For instance, "too little" leaf area (e.g., due to herbivory or disease) per unit of active stem mass would be expected to incur to low carbon income per respiratory cost and thus lead to lower growth. We present a framework that allows quantitative study of phenomena traditionally assigned to "stress," without need for recourse to this term. Our approach contrasts with traditional approaches for studying "stress," e.g., revealing that small "stressed" plants likely are in fact well suited to local conditions. We thus offer a quantitative perspective to the study of phenomena often referred to under such terms as "stress," plasticity, adaptation, and acclimation.

  15. Scaling relationship between rotation and translation motions

    NASA Astrophysics Data System (ADS)

    Chiu, Hung-Chie

    2016-04-01

    Rotation motion and its effects are not well known and our knowledge about translation motions is much better than that of the rotation motions. Since rotation motions show to have a close relationship with translation motions, deriving such relationship might improve our understanding on rotation motions. Rotation motion can be obtained by taking a spatial derivative of translation motion. Therefore, rotation motion is always accompanied by translation motions. Although rotation motion cannot be detected by strong motion record, the rotation-induced centrifugal acceleration and gravity effects are recorded in a strong-motion record. In this study we derive empirical relationships for rotation motion and its effects. Results show that rotation motion and its effects are small and can be ignored in weak motion, but they grow up very fast as the increasing of translation motion and become important in near-fault ground motions. We also found that those abnormal strong-motion records observed in near-fault are closely related to rotation motions.

  16. The relationship between cephalic scales and bones in lizards: a preliminary microtomographic survey on three lacertid species.

    PubMed

    Costantini, David; Alonso, Maria Lapresa; Moazen, Mehran; Bruner, Emiliano

    2010-02-01

    In the last two decades, there has been a great deal of interest in the morphology and anatomy of the lizard skull in an ecological and evolutionary perspective. However, the relationship between variations in many key anatomical features remains largely unknown. Using microtomography and geometric morphometrics, we examined the relationship between bones and scales associated with the parietal foramen in the three lizards species most common in the Italian peninsula: Podarcis muralis, P. sicula, and Lacerta bilineata. The imprints of the scales are clearly recognizable on the outer bone surface, and this may suggest a structural interaction between these elements. The temporal osteoderms are visible in the larger males and in the larger females of L. bilineata, but they are absent in the smaller specimens of L. bilineata and in all Podarcis specimens. Two parallel rows of pterygoid teeth are present in all the specimens of L. bilineata and are absent in the smaller male of L. bilineata and in both Podarcis species. Cheek osteoderms occurred only in the largest specimens of our sample (i.e., large L. bilineata), being possibly related to hyperostotic processes and densitometric thresholds more than to phylogeny. Minor differences may be also associated with the form of the parietal foramen. In absolute terms the parietal foramen tends to be largest in L. bilineata but in relation to skull length the foramen tends to be larger in P. muralis. In this latter species the foramen is also more elongated. In all three species the fronto-parietal suture occupies a similar location relatively to the scale spatial organization. A shared allometric pattern shows that the main vault enlargement can be localised at the areas anterior to the fronto-parietal suture, providing further information on the possible morphogenetic dynamics associated with the interaction between scales and bones around this structure.

  17. Scaling the respiratory metabolism to phosphorus relationship in plant seedlings

    PubMed Central

    Wang, Zhi-Qiang; Huang, Heng; Deng, Jian-Ming; Liu, Jian-Quan

    2015-01-01

    There are empirical indications of an isometric scaling relationship between plants’ respiratory metabolism rates and nitrogen contents. To test the hypothesis that there may be a similar relationship between plants’ respiratory metabolism and phosphorus contents we used data obtained from 150 laboratory and field-grown seedlings representing 30 herbaceous species and 20 woody deciduous species. Our results show that whole-plant respiration rates strongly scaled to the 0.81-power of the whole-plant phosphorus content, across wide ranges of growth conditions and functional classifications. Moreover, we also found a similar scaling exponent between whole-plant respiration rates and total nitrogen contents for the same set of samples. The similarities of the metabolic scaling relationships suggest that similar mechanisms may be involved in the transport and storage of phosphorus and nitrogen in plants. PMID:26560344

  18. 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.

  19. Allometric method to estimate leaf area index for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf area index (LAI) is critical for predicting plant metabolism, biomass production, evapotranspiration, and greenhouse gas sequestration, but direct LAI measurements are difficult and labor intensive. Several methods are available to measure LAI indirectly or calculate LAI using allometric method...

  20. Scaling--which methods best predict performance?

    PubMed

    Comfort, Paul; Pearson, Stephen J

    2014-06-01

    Athletes with a higher body mass (BM) tend to be stronger, with ratio scaling possibly eliminating this effect. The aim of this study was to compare relationships between sprint performances with scaled measures of strength and power. Fifteen professional rugby league players (age, 26.27 6 3.87 years; height, 183.33 6 6.37 cm; BM, 96.86 6 11.49 kg) performed 1 repetition maximum back squats, power cleans, squat jumps, and sprints (5, 10, and 20 m). Heavier athletes (forward) generated significantly greater absolute levels of power during the squat jump (5,659.11 6 710.35 vs.4,740.16 6 558.61 W; p , 0.001); however, when power data were scaled no differences were observed. Squat performance indicated no differences in absolute ability between the subgroups (190.6 6 14.25 vs. 205.7 6 18.35 kg), although the lighter group was significantly (p # 0.05) stronger than the heavier group when using ratio and allometric methods (2.1 vs. 1.9 kg · kg(-1) and 10.42 vs. 9.87 kg · kg(0.28)), respectively. Significant relationships with 5-m sprints were only observed for ratio and allometrically scaled power cleans (r = 20.625, p , 0.02; r = 20.675, p , 0.02), with similar correlations between allometrically scaled 10-m sprint and both back squat and power clean performances. Scaled power clean performances were also inversely correlated with 20-m sprints (r = 20.620, r = 20.638, p , 0.02). Where differences in absolute strength are apparent between individuals of different BM, then the use of scaling is required. Because of the similarity between ratio and allometric methods, simple ratio scaling is recommended.

  1. 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.

  2. Allometric equations for integrating remote sensing imagery into forest monitoring programmes.

    PubMed

    Jucker, Tommaso; Caspersen, John; Chave, Jérôme; Antin, Cécile; Barbier, Nicolas; Bongers, Frans; Dalponte, Michele; van Ewijk, Karin Y; Forrester, David I; Haeni, Matthias; Higgins, Steven I; Holdaway, Robert J; Iida, Yoshiko; Lorimer, Craig; Marshall, Peter L; Momo, Stéphane; Moncrieff, Glenn R; Ploton, Pierre; Poorter, Lourens; Rahman, Kassim Abd; Schlund, Michael; Sonké, Bonaventure; Sterck, Frank J; Trugman, Anna T; Usoltsev, Vladimir A; Vanderwel, Mark C; Waldner, Peter; Wedeux, Beatrice M M; Wirth, Christian; Wöll, Hannsjörg; Woods, Murray; Xiang, Wenhua; Zimmermann, Niklaus E; Coomes, David A

    2017-01-01

    Remote sensing is revolutionizing the way we study forests, and recent technological advances mean we are now able - for the first time - to identify and measure the crown dimensions of individual trees from airborne imagery. Yet to make full use of these data for quantifying forest carbon stocks and dynamics, a new generation of allometric tools which have tree height and crown size at their centre are needed. Here, we compile a global database of 108753 trees for which stem diameter, height and crown diameter have all been measured, including 2395 trees harvested to measure aboveground biomass. Using this database, we develop general allometric models for estimating both the diameter and aboveground biomass of trees from attributes which can be remotely sensed - specifically height and crown diameter. We show that tree height and crown diameter jointly quantify the aboveground biomass of individual trees and find that a single equation predicts stem diameter from these two variables across the world's forests. These new allometric models provide an intuitive way of integrating remote sensing imagery into large-scale forest monitoring programmes and will be of key importance for parameterizing the next generation of dynamic vegetation models.

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

    PubMed

    Greeley, Jeffrey

    2016-06-07

    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.

  4. 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.

  5. 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…

  6. Development of the cat-owner relationship scale (CORS).

    PubMed

    Howell, Tiffani J; Bowen, Jonathan; Fatjó, Jaume; Calvo, Paula; Holloway, Anna; Bennett, Pauleen C

    2017-03-07

    Characteristics of the human-animal bond can be influenced by both owner-related and pet-related factors, which likely differ between species. Three studies adapted the Monash Dog-Owner Relationship Scale (MDORS) to permit assessment of human-cat interactions as perceived by the cat's owner. In Study 1293 female cat owners completed a modified version of the MDORS, where 'dog' was replaced with 'cat' for all items. Responses were compared with a matched sample of female dog owners. A partial least squares discriminant analysis revealed systematic differences between cat and dog owners in the Dog (Cat)-Owner Interaction subscale (MDORS subscale 1), but not for Perceived Emotional Closeness or Perceived Costs (Subscales 2 and 3). Study 2 involved analysis of free-text descriptions of cat-owner interactions provided by 61 female cat owners. Text mining identified key words which were used to create additional questions for a new Cat-Owner Interaction subscale. In Study 3, the resulting cat-owner relationship scale (CORS) was tested in a group of 570 cat owners. The main psychometric properties of the scale, including internal consistency and factor structure, were evaluated. We propose that this scale can be used to accurately assess owner perceptions of their relationship with their cat. A modified scale, combining items from the CORS and MDORS (a C/DORS), is also provided for when researchers would find it desirable to compare human-cat and human-dog interactions.

  7. Concentration-Discharge Relationships Across Temporal and Spatial Scales

    NASA Astrophysics Data System (ADS)

    Godsey, S. E.; Kirchner, J. W.

    2005-12-01

    Hydrochemically diverse catchments in the USGS Hydrologic Benchmark Network exhibit power-law concentration-discharge relationships for the major base cations and silica. These 59 catchments exhibit diverse land cover and geology, and vary in size from ~6 to 6000 km2 with mean annual runoff between <1 and ~400 cm/year. At each of these catchments, concentrations typically decrease by a factor of approximately two to five while discharge increases by several orders of magnitude. These power-law relationships, with typical log-log slopes of -0.05 to -0.3, would not be expected in a kinetically-limited system where a constant chemical weathering flux is diluted by a variable water flux, even if a very large amount of subsurface storage is available. These observations imply that stream water solute concentrations are not directly controlled by kinetically-limited chemical weathering and solute mobilization processes. Furthermore, similar concentration-discharge relationships are also observed between mean annual concentration and annual discharge, implying that even on inter-annual time scales, kinetically-limited chemical weathering and solute mobilization processes do not directly regulate solute fluxes in streams. Similar power-law concentration-discharge relationships are observed at most sites, regardless of spatial scale. The slopes of the concentration-discharge relationships are not significantly correlated with catchment area or other landscape attributes. The observed concentration-discharge relationship is a general phenomenon across a wide range of temporal and spatial scales, as well as geologic and hydrologic environments, and therefore demands a general explanation. Simple mixing models are unable to reproduce the observed concentration-discharge relationships. We explore several new models to explain the observed patterns.

  8. Do insect metabolic rates at rest and during flight scale with body mass?

    PubMed

    Niven, Jeremy E; Scharlemann, Jörn P W

    2005-09-22

    Energetically costly behaviours, such as flight, push physiological systems to their limits requiring metabolic rates (MR) that are highly elevated above the resting MR (RMR). Both RMR and MR during exercise (e.g. flight or running) in birds and mammals scale allometrically, although there is little consensus about the underlying mechanisms or the scaling relationships themselves. Even less is known about the allometric scaling of RMR and MR during exercise in insects. We analysed data on the resting and flight MR (FMR) of over 50 insect species that fly to determine whether RMR and FMR scale allometrically. RMR scaled with body mass to the power of 0.66 (M0.66), whereas FMR scaled with M1.10. Further analysis suggested that FMR scaled with two separate relationships; insects weighing less than 10mg had fourfold lower FMR than predicted from the scaling of FMR in insects weighing more than 10mg, although both groups scaled with M0.86. The scaling exponents of RMR and FMR in insects were not significantly different from those of birds and mammals, suggesting that they might be determined by similar factors. We argue that low FMR in small insects suggests these insects may be making considerable energy savings during flight, which could be extremely important for the physiology and evolution of insect flight.

  9. 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.

  10. Controls on scaling relationships of dynamic headwater stream networks

    NASA Astrophysics Data System (ADS)

    Godsey, S.; Kirchner, J. W.; Whiting, J. A.

    2013-12-01

    Stream networks expand and contract within their channel network, particularly within their headwaters. Along their length, especially during drought periods, it is not unusual to encounter dry reaches of varying lengths. Controls on the length and location of those dry reaches include: large woody debris, upstream sediment loading, hydraulic properties of the subsurface/hyporheic zone, and the catchment hydroclimate and morphology. Here we examine patterns in the length of discontinuous reaches, their location, and the length of the overall drainage network. We find that drainage networks expand with discharge as a power-law relationship with a slope of ~0.25, contradicting recent theoretical suggestions in the literature that this scaling exponent should be close to 1.0. We discuss physical limitations on the range of potential scaling relationships, and link stream responses to groundwater and evapotranspiration sources and sinks.

  11. 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.

  12. 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.

  13. Relationship Status: Scales for Assessing the Vitality of Late Adolescents' Relationships with Their Parents.

    ERIC Educational Resources Information Center

    Klos, Dennis S.; Paddock, John R.

    1978-01-01

    Three criteria for assessing parent-child relationships were proposed: self-disclosure despite risk of parental disapproval; openness to critical feedback from parents; and constructive confrontation when angry with parents. These concepts were operationalized as narratives of parent-adolescent dilemmas. Scales were constructed and cross validated…

  14. 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…

  15. 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.

  16. 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

  17. Scaling relationship and optimization of double-pulse electroporation.

    PubMed

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

    2014-02-18

    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.

  18. Quantifying the Relationship Between Drainage Networks at Hillslope Scale and Particle Size Distribution at Pedon Scale

    NASA Astrophysics Data System (ADS)

    Cámara, Joaquín; Martín, Miguel Ángel; Gómez-Miguel, Vicente

    2015-02-01

    Nowadays, translating information about hydrologic and soil properties and processes across scales has emerged as a major theme in soil science and hydrology, and suitable theories for upscaling or downscaling hydrologic and soil information are being looked forward. The recognition of low-order catchments as self-organized systems suggests the existence of a great amount of links at different scales between their elements. The objective of this work was to research in areas of homogeneous bedrock material, the relationship between the hierarchical structure of the drainage networks at hillslope scale and the heterogeneity of the particle-size distribution at pedon scale. One of the most innovative elements in this work is the choice of the parameters to quantify the organization level of the studied features. The fractal dimension has been selected to measure the hierarchical structure of the drainage networks, while the Balanced Entropy Index (BEI) has been the chosen parameter to quantify the heterogeneity of the particle-size distribution from textural data. These parameters have made it possible to establish quantifiable relationships between two features attached to different steps in the scale range. Results suggest that the bedrock lithology of the landscape constrains the architecture of the drainage networks developed on it and the particle soil distribution resulting in the fragmentation processes.

  19. Evolution of static allometries: adaptive change in allometric slopes of eye span in stalk-eyed flies.

    PubMed

    Voje, Kjetil L; Hansen, Thomas F

    2013-02-01

    Julian Huxley showed that within-species (static) allometric (power-law) relations can arise from proportional growth regulation with the exponent in the power law equaling the factor of proportionality. Allometric exponents may therefore be hard to change and act as constraints on the independent evolution of traits. In apparent contradiction to this, many empirical studies have concluded that static allometries are evolvable. Many of these studies have been based, however, on a broad definition of allometry that includes any monotonic shape change with size, and do not falsify the hypothesis of constrained narrow-sense allometry. Here, we present the first phylogenetic comparative study of narrow-sense allometric exponents based on a reanalysis of data on eye span and body size in stalk-eyed flies (Diopsidae). Consistent with a role in sexual selection, we found strong evidence that male slopes were tracking "optima" based on sexual dimorphism and relative male trait size. This tracking was slow, however, with estimated times of 2-3 million years for adaptation to exceed ancestral influence on the trait. Our results are therefore consistent with adaptive evolution on million-year time scales, but cannot rule out that static allometry may act as a constraint on eye-span adaptation at shorter time scales.

  20. 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.

  1. 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

  2. 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

  3. 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

  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.

  5. 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.

  6. 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

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

    PubMed

    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

    2010-01-26

    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.

  8. 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

  9. Conservative whole-organ scaling contrasts with highly labile suborgan scaling differences among compound eyes of closely related Formica ants.

    PubMed

    Perl, Craig D; Rossoni, Sergio; Niven, Jeremy E

    2017-03-01

    Static allometries determine how organ size scales in relation to body mass. The extent to which these allometric relationships are free to evolve, and how they differ among closely related species, has been debated extensively and remains unclear; changes in intercept appear common, but changes in slope are far rarer. Here, we compare the scaling relationships that govern the structure of compound eyes of four closely related ant species from the genus Formica. Comparison among these species revealed changes in intercept but not slope in the allometric scaling relationships governing eye area, facet number, and mean facet diameter. Moreover, the scaling between facet diameter and number was conserved across all four species. In contrast, facet diameters from distinct regions of the compound eye differed in both intercept and slope within a single species and when comparing homologous regions among species. Thus, even when species are conservative in the scaling of whole organs, they can differ substantially in regional scaling within organs. This, at least partly, explains how species can produce organs that adhere to genus wide scaling relationships while still being able to invest differentially in particular regions of organs to produce specific features that match their ecology.

  10. Channel Forming Discharges and Scaling Relationships in Small Streams

    NASA Astrophysics Data System (ADS)

    Brayshaw, D. D.

    2008-12-01

    One of the major challenges in predicting or mitigating the impacts of disturbance on hydrologic systems is to link changes in hydrology to changes in sediment delivery and transport. Because of the complexity of modelling, usually only one system is considered in isolation, with any potential changes in the corresponding system inferred. For instance, a study of a small watershed might consider changes to peak flows or to sediment delivery to the channel, but not alteration in channel pattern caused by those changes. Linking our understanding of expected changes in hydrology and sediment transport is therefore important for improving land use management. In order to improve this understanding, the development of models and concepts linking hydrologic change to geomorphic change, and vice versa, is necessary. Channel and reach parameters (such as width, depth, slope, and channel pattern) reflect the adjustment of the stream channel to inputs of water, wood and sediment from upstream and upslope. Therefore, channel parameters can be used as indicators which synthesize the hydrologic and geomorphic processes occurring in a watershed (Goodwin et al, 1998). Two parameters which are particularly relevant are the bankfull discharge and the effective discharge. Bankfull discharge (Wolman and Leopold, 1957) is defined as the discharge at which the stream channel is full to the top of its banks, but not flooding over the bank. Effective discharge (Wolman and Miller, 1960) is defined as the discharge that, averaged over time, transports the most sediment. Estimating the frequency, magnitude, and duration of bankfull and effective discharge in a single stream reach provides an indication of the stream channel's stability and the frequency with which geomorphically effective events occur in the watershed upstream. Determining the bankfull and effective discharge for multiple streams across a region enables regionalization, consideration of scaling relationships, and evaluation

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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).

  16. Allometric Analysis Detects Brain Size-Independent Effects of Sex and Sex Chromosome Complement on Human Cerebellar Organization.

    PubMed

    Mankiw, Catherine; Park, Min Tae M; Reardon, P K; Fish, Ari M; Clasen, Liv S; Greenstein, Deanna; Giedd, Jay N; Blumenthal, Jonathan D; Lerch, Jason P; Chakravarty, M Mallar; Raznahan, Armin

    2017-03-17

    The cerebellum is a large hindbrain structure that is increasingly recognized for its contribution to diverse domains of cognitive and affective processing in human health and disease. Although several of these domains are sex-biased, our fundamental understanding of cerebellar sex differences - including their spatial distribution, potential biological determinants, and independence from brain volume variation - lags far behind that for the cerebrum. Here, we harness automated neuroimaging methods for cerebellar morphometrics in 417 individuals to (i) localize normative male-female differences in raw cerebellar volume, (ii) compare these to sex chromosome effects estimated across five rare X-/Y-chromosome aneuploidy (SCA) syndromes, and (iii) clarify brain size-independent effects of sex and SCA on cerebellar anatomy using a generalizable allometric approach which considers scaling relationships between regional cerebellar volume and brain volume in health. Integration of these approaches shows that (i) sex and SCA effects on raw cerebellar volume are large and distributed, but regionally heterogeneous, (ii) human cerebellar volume scales with brain volume in a highly non-linear and regionally heterogeneous fashion that departs from documented patterns of cerebellar scaling in phylogeny, and (iii) cerebellar organization is modified in a brain size-independent manner by sex (relative expansion of total cerebellum, flocculus, and Crus II-lobule VIIIB volumes in males) and SCA (contraction of total cerebellar, lobule IV and Crus I volumes with additional X- or Y-chromosomes; X-specific contraction of Crus II-lobule VIIIB). Our methods and results clarify the shifts in human cerebellar organization that accompany interwoven variations in sex, sex chromosome complement, and brain size.SIGNIFICANCE STATEMENTCerebellar systems are implicated in diverse domains of sex-biased behavior and pathology, but we lack a basic understanding of how sex differences in the human

  17. 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.

  18. Relationship between small and large sedimentary basins: the scale spectrum

    SciTech Connect

    Dewey, J.F.; Karner, G.D.; Pitman, W.C.

    1986-07-01

    Realizing that detachments influence lithospheric extension helps us define the fundamental elements responsible for basin formation. In addition to strain rate, crustal thickness, and lithospheric thickness, these factors are (1) stretching distribution within the upper plate of the detachment, (2) stretching distribution within the lower plate, and (3) depth distribution of the detachment(s), where lateral strain must be balanced within the lithosphere during extension. Intracrustal duplex systems may reflect previous compressional events, or they may be produced by upper-crustal flaking in strike-slip regimes. Basin initiation represents a mechanical process (e.g., hanging-wall collapse), whereas subsequent basin development is primarily an isostatic process controlled by the thermal and mechanical properties of the lithosphere. However, subcrustal lithospheric involvement and, hence, heating are minimal until flexure becomes unimportant, which depends on basin wavelength, lithospheric temperature structure, and hence, rigidity. This wavelength or scale dependency may help explain the difference between the abrupt but short-lived subsidence of small basins, such as the Ridge basin of southern California, and the general negative exponential subsidence characteristic of passive continental margins. The rheological implications of depth-dependent stretching, with thermal modification of the lithosphere during extension, ultimately controls lithospheric strength and, hence, the actual rift/breakup configuration. Together, factors 1 and 2 generate rift and thermal subsidences, the final form of which depends on the flexural properties of the lithosphere. The exact relationship between factors 1 and 2 determines the spatial configuration between rift and sag basins and temporary uplifts. They illustrate these concepts and their implications with examples from California, Nevada, Brazil, Turkey, and Australia.

  19. Testing the cranial evolutionary allometric 'rule' in Galliformes.

    PubMed

    Linde-Medina, M

    2016-09-01

    Recent comparative studies have indicated the existence of a common cranial evolutionary allometric (CREA) pattern in mammals and birds, in which smaller species have relatively smaller faces and bigger braincases than larger species. In these studies, cranial allometry was tested using a multivariate regression between shape (described using landmarks coordinates) and size (i.e. centroid size), after accounting for phylogenetic relatedness. Alternatively, cranial allometry can be determined by comparing the sizes of two anatomical parts using a bivariate regression analysis. In this analysis, a slope higher or lower than one indicates the existence of positive or negative allometry, respectively. Thus, in those species that support the CREA 'rule', positive allometry is expected for the association between face size and braincase size, which would indicate that larger species have disproportionally larger faces. In this study, I applied these two approaches to explore cranial allometry in 83 Galliformes (Aves, Galloanserae), ranging in mean body weight from 30 g to 2.5 kg. The multivariate regression between shape and centroid size revealed the existence of a significant allometric pattern resembling CREA, whereas the second analysis revealed a negative allometry for beak size and braincase size (i.e. contrary to the CREA 'rule', larger galliform species have disproportionally shorter beaks than smaller galliform species). This study suggests that the presence of CREA may be overestimated when using cranium size as the standard measurement.

  20. 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

  1. The Student-Teacher Relationship Scale: Results of a Pilot Study.

    ERIC Educational Resources Information Center

    Pianta, Robert C.; Nimetz, Sheri L.

    This study reports the results of a pilot study of the relationship between teachers and students. The study used a newly developed measure: The Student-Teacher Relationship Scale (STRS). In a sample of 72 kindergarten children, the STRS was found to have three factors: Secure, Change, and Insecure. The total scale and the subscales based on these…

  2. Basic Relationships among Scale, Quality, and Benefits in Sino-Foreign Cooperative Education

    ERIC Educational Resources Information Center

    Lin, Jinhui

    2016-01-01

    The basic relationships among scale, quality, and benefits in Sino-foreign cooperative education are key to the development of cooperative education. It is necessary to construct a theoretical framework for the basic relationships among scale, quality, and benefits in Sino-foreign cooperative education and analyze the questions faced in…

  3. Allometric Trajectories and “Stress”: A Quantitative Approach

    PubMed Central

    Anfodillo, Tommaso; Petit, Giai; Sterck, Frank; Lechthaler, Silvia; Olson, Mark E.

    2016-01-01

    The term “stress” is an important but vague term in plant biology. We show situations in which thinking in terms of “stress” is profitably replaced by quantifying distance from functionally optimal scaling relationships between plant parts. These relationships include, for example, the often-cited one between leaf area and sapwood area, which presumably reflects mutual dependence between sources and sink tissues and which scales positively within individuals and across species. These relationships seem to be so basic to plant functioning that they are favored by selection across nearly all plant lineages. Within a species or population, individuals that are far from the common scaling patterns are thus expected to perform negatively. For instance, “too little” leaf area (e.g., due to herbivory or disease) per unit of active stem mass would be expected to incur to low carbon income per respiratory cost and thus lead to lower growth. We present a framework that allows quantitative study of phenomena traditionally assigned to “stress,” without need for recourse to this term. Our approach contrasts with traditional approaches for studying “stress,” e.g., revealing that small “stressed” plants likely are in fact well suited to local conditions. We thus offer a quantitative perspective to the study of phenomena often referred to under such terms as “stress,” plasticity, adaptation, and acclimation. PMID:27881990

  4. 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…

  5. Relationships between persistent large-scale flow anomalies and variation in synoptic-scale eddy activity and cyclogenesis

    NASA Technical Reports Server (NTRS)

    Dole, Randall M.; Neilley, Peter P.

    1988-01-01

    Observational analyses to study the relationships between large-scale flow anomalies and variations in synoptic-scale eddy activity and cyclogenesis are presented. The way in which changes in the large-scale flow influence the behavior of synoptic-scale eddies and the way in which changes in eddies may feedback to influence the large-scale flow anomalies are examined. Situations characterized by differing large-scale flows are compared, showing well-defined diferences in synoptic-scale eddy activity. The net forcings of anomalous mean flows by eddies as deduced from tendency methods and E-vector analyses suggest that synoptic-scale eddies may play an important role in maintaining certain anomalous flow patterns such as blocking.

  6. 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

  7. 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

    2015-09-15

    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.

  8. Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales).

    PubMed

    Neustupa, J

    2016-02-01

    The surface area-to-volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface-to-volume scaling involves fractal-like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface-to-volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species-specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors.

  9. Scale-invariant structure of size fluctuations in plants

    PubMed Central

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

    2012-01-01

    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. PMID:22439105

  10. 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.

  11. 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…

  12. 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…

  13. Assessing client-caregiver relationships and the applicability of the 'student-teacher relationship scale' for people with intellectual disabilities.

    PubMed

    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 instruments are needed. This study examines the applicability of an existing relationship questionnaire designed for primary education, called the Student-Teacher Relationship Scale (STRS) on the basis of the following research questions: (1) What is the factor structure of the STRS? (2) Are there associations between STRS scales and other conceptually comparable instruments? (3) Is the STRS reliable? The participants in this study were 46 caregivers, who assessed 350 client-caregiver relationships. Psychometric research was conducted into the factor structure (n=350), construct validity (n=146), internal consistency (n=350) and test-retest reliability (n=177) of the STRS and the reliability of the individual scores (n=350) among a study population of people with moderate and severe ID. The three-factor model of the STRS as used in primary education (1. closeness, 2. conflict, 3. dependency) was, despite minor deviations, also found in the ID population. Research into the construct validity of the STRS showed statistically significant correlations with other scales with which similarities could be expected. The internal consistency and test-retest reliability of the STRS in the population studied were very good. The 95% confidence intervals of the means were small, and these measurements can be regarded as reliable.

  14. 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.

  15. A critical review and database of biomass and volume allometric equation for trees and shrubs of Bangladesh

    NASA Astrophysics Data System (ADS)

    Mahmood, H.; Siddique, M. R. H.; Akhter, M.

    2016-08-01

    Estimations of biomass, volume and carbon stock are important in the decision making process for the sustainable management of a forest. These estimations can be conducted by using available allometric equations of biomass and volume. Present study aims to: i. develop a compilation with verified allometric equations of biomass, volume, and carbon for trees and shrubs of Bangladesh, ii. find out the gaps and scope for further development of allometric equations for different trees and shrubs of Bangladesh. Key stakeholders (government departments, research organizations, academic institutions, and potential individual researchers) were identified considering their involvement in use and development of allometric equations. A list of documents containing allometric equations was prepared from secondary sources. The documents were collected, examined, and sorted to avoid repetition, yielding 50 documents. These equations were tested through a quality control scheme involving operational verification, conceptual verification, applicability, and statistical credibility. A total of 517 allometric equations for 80 species of trees, shrubs, palm, and bamboo were recorded. In addition, 222 allometric equations for 39 species were validated through the quality control scheme. Among the verified equations, 20%, 12% and 62% of equations were for green-biomass, oven-dried biomass, and volume respectively and 4 tree species contributed 37% of the total verified equations. Five gaps have been pinpointed for the existing allometric equations of Bangladesh: a. little work on allometric equation of common tree and shrub species, b. most of the works were concentrated on certain species, c. very little proportion of allometric equations for biomass estimation, d. no allometric equation for belowground biomass and carbon estimation, and d. lower proportion of valid allometric equations. It is recommended that site and species specific allometric equations should be developed and

  16. 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.

  17. 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.

  18. The relationships among three habitat scales and stream benthic invertebrate community structure

    USGS Publications Warehouse

    Carter, J.L.; Fend, S.V.; Kennelly, S.S.

    1996-01-01

    6. There was no clear relationship between species richness and altitude on a site basis. However, when viewed at the basin scale, maximum richness was observed at the transition between montane and valley sites.

  19. Spatially varying relationships between land-cover change and driving factors at multiple sampling scales.

    PubMed

    Du, Shihong; Wang, Qiao; Guo, Luo

    2014-05-01

    Modeling the relationships between environment, human activity, and natural conditions is very important for understanding human-environment interactions. This study aims at examining how these relationships vary over spatial sampling scales and investigating the spatially varying relationships between land-cover changes and driving factors, as well as the variations in the relationships at different sampling scales in the Tibetan Autonomous Prefecture of Qinghai Province, P.R. China. Regular sampling methods are used first to generate eight sets of data points at different scales, and then the values for land-cover changes and the factors are extracted for these data points. Geographically weighted regression (GWR) model is applied to analyze the relationships between land-cover changes and the factors at different sampling scales. The results indicate that the influences of the factors (e.g. the signs, significances, and values of coefficients) change greatly over different sampling scales; similarly, for different types of land-cover changes, the contributions of the factors also vary. Generally, roads, rivers, and lakes contribute greatly to land-cover changes, while villages, temples, and elevations contribute less. A possible reason is that the densities of roads, rivers, and lakes is much greater than those of villages and temples, and the populations in temples and villages are too small to have much effect on land-cover changes. The results demonstrate that the sampling scales have an important influence on the relationships between land-cover change and the factors.

  20. Scaling of nitrogen and phosphorus across plant organs in shrubland biomes across Northern China.

    PubMed

    Yang, Xian; Tang, Zhiyao; Ji, Chengjun; Liu, Hongyan; Ma, Wenhong; Mohhamot, Anwar; Shi, Zhaoyong; Sun, Wei; Wang, Tao; Wang, Xiangping; Wu, Xian; Yu, Shunli; Yue, Ming; Zheng, Chengyang

    2014-06-26

    Allocation of limiting resources, such as nutrients, is an important adaptation strategy for plants. Plants may allocate different nutrients within a specific organ or the same nutrient among different organs. In this study, we investigated the allocation strategies of nitrogen (N) and phosphorus (P) in leaves, stems and roots of 126 shrub species from 172 shrubland communities in Northern China using scaling analyses. Results showed that N and P have different scaling relationships among plant organs. The scaling relationships of N concentration across different plant organs tended to be allometric between leaves and non-leaf organs, and isometric between non-leaf organs. Whilst the scaling relationships of P concentration tended to be allometric between roots and non-root organs, and isometric between non-root organs. In arid environments, plant tend to have higher nutrient concentration in leaves at given root or stem nutrient concentration. Evolutionary history affected the scaling relationships of N concentration slightly, but not affected those of P concentration. Despite fairly consistent nutrients allocation strategies existed in independently evolving lineages, evolutionary history and environments still led to variations on these strategies.

  1. Scaling of nitrogen and phosphorus across plant organs in shrubland biomes across Northern China

    PubMed Central

    Yang, Xian; Tang, Zhiyao; Ji, Chengjun; Liu, Hongyan; Ma, Wenhong; Mohhamot, Anwar; Shi, Zhaoyong; Sun, Wei; Wang, Tao; Wang, Xiangping; Wu, Xian; Yu, Shunli; Yue, Ming; Zheng, Chengyang

    2014-01-01

    Allocation of limiting resources, such as nutrients, is an important adaptation strategy for plants. Plants may allocate different nutrients within a specific organ or the same nutrient among different organs. In this study, we investigated the allocation strategies of nitrogen (N) and phosphorus (P) in leaves, stems and roots of 126 shrub species from 172 shrubland communities in Northern China using scaling analyses. Results showed that N and P have different scaling relationships among plant organs. The scaling relationships of N concentration across different plant organs tended to be allometric between leaves and non-leaf organs, and isometric between non-leaf organs. Whilst the scaling relationships of P concentration tended to be allometric between roots and non-root organs, and isometric between non-root organs. In arid environments, plant tend to have higher nutrient concentration in leaves at given root or stem nutrient concentration. Evolutionary history affected the scaling relationships of N concentration slightly, but not affected those of P concentration. Despite fairly consistent nutrients allocation strategies existed in independently evolving lineages, evolutionary history and environments still led to variations on these strategies. PMID:24965183

  2. 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 –...

  3. 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…

  4. An allometric analysis of the giraffe cardiovascular system.

    PubMed

    Mitchell, G; Skinner, J D

    2009-12-01

    There has been co-evolution of a long neck and high blood pressure in giraffes. How the cardiovascular system (CVS) has adapted to produce a high blood pressure, and how it compares with other similar sized mammals largely is unknown. We have measured body mass and heart structure in 56 giraffes of both genders ranging in body mass from 18 kg to 1500 kg, and developed allometric equations that relate changes in heart dimensions to growth and to cardiovascular function. Predictions made from these equations match measurements made in giraffes. We have found that heart mass increases as body mass increases but it has a relative mass of 0.51+/-0.7% of body mass which is the same as that in other mammals. The left ventricular and interventricular walls are hypertrophied and their thicknesses are linearly related to neck length. Systemic blood pressure increases as body mass and neck length increase and is twice that of mammals of the same body mass. Cardiac output is the same as, but peripheral resistance double that predicted for similar sized mammals. We have concluded that increasing hydrostatic pressure of the column of blood during neck elongation results in cardiac hypertrophy and concurrent hypertrophy of arteriole walls raising peripheral resistance, with an increase in blood pressure following.

  5. 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…

  6. 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…

  7. 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.

  8. Spatial scale and species identity influence the indigenous-alien diversity relationship in springtails.

    PubMed

    Terauds, Aleks; Chown, Steven L; Bergstrom, Dana M

    2011-07-01

    Although theory underlying the invasion paradox, or the change in the relationship between the richness of alien and indigenous species from negative to positive with increasing spatial scale, is well developed and much empirical work on the subject has been undertaken, most of the latter has concerned plants and to a lesser extent marine invertebrates. Here we therefore examine the extent to which the relationships between indigenous and alien species richness change from the local metacommunity to the interaction neighborhood scales, and the influences of abundance, species identity, and environmental favorability thereon, in springtails, a significant component of the soil fauna. Using a suite of modeling techniques, including generalized least squares and geographically weighted regressions to account for spatial autocorrelation or nonstationarity of the data, we show that the abundance and species richness of both indigenous and alien species at the metacommunity scale respond strongly to declining environmental favorability, represented here by altitude. Consequently, alien and indigenous diversity covary positively at this scale. By contrast, relationships are more complex at the interaction neighborhood scale, with the relationship among alien species richness and/or density and the density of indigenous species varying between habitats, being negative in some, but positive in others. Additional analyses demonstrated a strong influence of species identity, with negative relationships identified at the interaction neighborhood scale involving alien hypogastrurid springtails, a group known from elsewhere to have negative effects on indigenous species in areas where they have been introduced. By contrast, diversity relationships were positive with the other alien species. These results are consistent with both theory and previous empirical findings for other taxa, that interactions among indigenous and alien species change substantially with spatial scale and

  9. Multi-functional scaling methodology for translational pharmacokinetic and pharmacodynamic applications using integrated microphysiological systems (MPS).

    PubMed

    Maass, Christian; Stokes, Cynthia L; Griffith, Linda G; Cirit, Murat

    2017-03-07

    Microphysiological systems (MPS) provide relevant physiological environments in vitro for studies of pharmacokinetics, pharmacodynamics and biological mechanisms for translational research. Designing multi-MPS platforms is essential to study multi-organ systems. Typical design approaches, including direct and allometric scaling, scale each MPS individually and are based on relative sizes not function. This study's aim was to develop a new multi-functional scaling approach for integrated multi-MPS platform design for specific applications. We developed an optimization approach using mechanistic modeling and specification of an objective that considered multiple MPS functions, e.g., drug absorption and metabolism, simultaneously to identify system design parameters. This approach informed the design of two hypothetical multi-MPS platforms consisting of gut and liver (multi-MPS platform I) and gut, liver and kidney (multi-MPS platform II) to recapitulate in vivo drug exposures in vitro. This allows establishment of clinically relevant drug exposure-response relationships, a prerequisite for efficacy and toxicology assessment. Design parameters resulting from multi-functional scaling were compared to designs based on direct and allometric scaling. Human plasma time-concentration profiles of eight drugs were used to inform the designs, and profiles of an additional five drugs were calculated to test the designed platforms on an independent set. Multi-functional scaling yielded exposure times in good agreement with in vivo data, while direct and allometric scaling approaches resulted in short exposure durations. Multi-functional scaling allows appropriate scaling from in vivo to in vitro of multi-MPS platforms, and in the cases studied provides designs that better mimic in vivo exposures than standard MPS scaling methods.

  10. 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.

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

    PubMed

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

    2014-09-23

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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.

  13. 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

    2016-08-24

    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.

  14. 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

  15. 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

  16. Patterns of cranial ontogeny in lacertid lizards: morphological and allometric disparity.

    PubMed

    Urošević, A; Ljubisavljević, K; Ivanović, A

    2013-02-01

    We explored the ontogenetic dynamics of the morphological and allometric disparity in the cranium shapes of twelve lacertid lizard species. The analysed species (Darevskia praticola, Dinarolacerta mosorensis, Iberolacerta horvathi, Lacerta agilis, L. trilineata, L. viridis, Podarcis erhardii, P. melisellensis, P. muralis, P. sicula, P. taurica and Zootoca vivipara) can be classified into different ecomorphs: terrestrial lizards that inhabit vegetated habitats (habitats with lush or sparse vegetation), saxicolous and shrub-climbing lizards. We observed that there was an overall increase in the morphological disparity (MD) during the ontogeny of the lacertid lizards. The ventral cranium, which is involved in the mechanics of jaw movement and feeding, showed higher levels of MD, an ontogenetic shift in the morphospace planes and more variable allometric patterns than more conserved dorsal crania. With respect to ecology, the allometric trajectories of the shrub-climbing species tended to cluster together, whereas the allometric trajectories of the saxicolous species were highly dispersed. Our results indicate that the ontogenetic patterns of morphological and allometric disparity in the lacertid lizards are modified by ecology and functional constraints and that the identical mechanisms that lead to intraspecific morphological variation also produce morphological divergence at higher taxonomic levels.

  17. 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.

  18. 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.

  19. The relationship of MMPI and Sensation Seeking Scales to adolescent drug use.

    PubMed

    Andrucci, G L; Archer, R P; Pancoast, D L; Gordon, R A

    1989-01-01

    This study examined the relationship of Minnesota Multiphasic Personality Inventory (MMPI) measures, including the MacAndrew alcoholism (MAC) scale, and the Sensation Seeking Scales (SSS) to adolescents' drug use across nine drug categories. Subjects were 51 male and 72 female high school students between the ages of 14 and 18 (mean age = 16 years, 5 months). The drug use/abuse measure consisted of adolescents' self-reports on the Segal (1973) Alcohol-Drug Use Research Survey. Drug categories included for investigation were alcohol, amphetamines, barbiturates, caffeine, cocaine, hallucinogens, marijuana, narcotics, and tobacco. Scores from standard MMPI scales, the MAC scale, and the SSS were examined in relation to individual drug use outcomes, and multivariate procedures were used to predict polydrug versus single drug use patterns. Results demonstrated significant and meaningful relationships between personality measures and drug use among adolescents, with consistently strong findings for the SSS.

  20. Relationship between Hounsfield unit in CT scan and gray scale in CBCT

    NASA Astrophysics Data System (ADS)

    Kamaruddin, Noorshaida; Rajion, Zainul Ahmad; Yusof, Asilah; Aziz, Mohd Ezane

    2016-12-01

    Cone-beam computed tomography (CBCT) is an imaging system which has advantages over computed tomography (CT). Recently, CBCT has become widely used for oral and maxillofacial imaging. In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present (in vitro) study was to investigate the relationship between gray scale in CBCT and HU in CT scan. In this descriptive study, the anthropomorphic head phantom was scanned with CBCT and CT scanner. Gray scales and HUs were detected on images at the crown of the teeth, trabecular and cortical bone of mandible. The images were analyzed to obtain the gray scale value and HU value. The obtained value then used to investigate the relationship between CBCT gray scales and HUs. For the statistical analysis, t-test, Pearson's correlation and regression analysis were used. The differences between the gray scale of CBCT and HU of CT were statistically not significant, whereas the Pearson's correlation coefficients demonstrated a statistically significant correlation between gray scale of CBCT and HU of CT values. Considering the fact that gray scale in CBCT is important in pre assessment evaluation of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  1. On identifying relationships between the flood scaling exponent and basin attributes.

    PubMed

    Medhi, Hemanta; Tripathi, Shivam

    2015-07-01

    Floods are known to exhibit self-similarity and follow scaling laws that form the basis of regional flood frequency analysis. However, the relationship between basin attributes and the scaling behavior of floods is still not fully understood. Identifying these relationships is essential for drawing connections between hydrological processes in a basin and the flood response of the basin. The existing studies mostly rely on simulation models to draw these connections. This paper proposes a new methodology that draws connections between basin attributes and the flood scaling exponents by using observed data. In the proposed methodology, region-of-influence approach is used to delineate homogeneous regions for each gaging station. Ordinary least squares regression is then applied to estimate flood scaling exponents for each homogeneous region, and finally stepwise regression is used to identify basin attributes that affect flood scaling exponents. The effectiveness of the proposed methodology is tested by applying it to data from river basins in the United States. The results suggest that flood scaling exponent is small for regions having (i) large abstractions from precipitation in the form of large soil moisture storages and high evapotranspiration losses, and (ii) large fractions of overland flow compared to base flow, i.e., regions having fast-responding basins. Analysis of simple scaling and multiscaling of floods showed evidence of simple scaling for regions in which the snowfall dominates the total precipitation.

  2. 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

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

    USGS Publications Warehouse

    Ward, G.A.; Smith, T. J.; 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.

  4. 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

  5. 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…

  6. Further Examination of the Convergent and Discriminant Validity of the Student-Teacher Relationship Scale

    ERIC Educational Resources Information Center

    Doumen, Sarah; Verschueren, Karine; Buyse, Evelien; De Munter, Sofie; Max, Kristel; Moens, Loth

    2009-01-01

    Two studies extended psychometric research on the Student-Teacher Relationship Scale (STRS) with kindergarten and preschool children (N[subscript 1] = 60-7[subscript 1]; N[subscript 2] = 35) and their teachers. These studies used a multi-method approach to replicate and extend previous findings concerning the convergent validity of the STRS…

  7. The Three Dimensions of the Student-Teacher Relationship Scale: CFA Validation in a Preschool Sample

    ERIC Educational Resources Information Center

    Solheim, Elisabet; Berg-Nielsen, Turid Suzanne; Wichstrom, Lars

    2012-01-01

    The validity of the Student-Teacher Relationship Scale (STRS) was examined in a preschool community sample (N = 925) using confirmatory factor analysis (CFA). Factorial invariance across genders was also investigated as was concurrent and discriminant validity. Indicators of validity were teacher-rated social competence, problem behavior, and…

  8. 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.…

  9. Validity and Utility of the Parent--Teacher Relationship Scale-II

    ERIC Educational Resources Information Center

    Dawson, Anne E.; Wymbs, Brian T.

    2016-01-01

    Preliminary findings indicate that positive relations between parents and teachers are associated with successful school outcomes for children. However, measures available to assess parent-teacher relations are scant. The current study examined validity evidence for the Parent-Teacher Relationship Scale-I (PTRS). Specifically, the internal…

  10. 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),…

  11. 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…

  12. Relationships Between the 1960 Stanford-Binet Scale and Group Measures of Intelligence and Achievement

    ERIC Educational Resources Information Center

    Churchill, William D.; Smith, Stuart E.

    1974-01-01

    This study is concerned with the determination of relationships between the 1960 Revised Stanford-Binet Intelligence Scale, the Lorge-Thorndike Intelligence Test, and the Iowa Tests of Basic Skills. The primary objective of the investigation was to determine the predictive validity of the 1960 Stanford-Binet over a period of eight years. (Author)

  13. 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…

  14. Relationship between manual dexterity and the unified parkinson's disease rating scale-motor exam.

    PubMed

    Hwang, Sujin; Song, Chiang-Soon

    2016-12-01

    [Purpose] The purpose of this study was to examine the relationships between manual dexterity and the Unified Parkinson's Disease Rating Scale-Motor Exam as a clinical tool for quantifying upper extremity function in persons with Parkinson's disease. [Subjects and Methods] Thirty-two persons with idiopathic Parkinson's disease participated in this study. This study measured two clinical outcomes, the box-and-block test and the Unified Parkinson's Disease Rating Scale-Motor Exam, to investigate the relationships between manual dexterity and the Unified Parkinson's Disease Rating Scale-Motor Exam. [Results] The box-and-block test on the more affected side was positive relationship with the box-and-block test on the less affected side. The Unified Parkinson's Disease Rating Scale-motor exam score had a negative correlation with the box-and-block test results for both sides. [Conclusion] A positive association was noted between manual dexterity and motor function in patients with idiopathic Parkinson disease. The results of this study suggest that the box-and-block test and the Unified Parkinson's Disease Rating Scale-Motor Exam are good clinical measures that quantify upper extremity function and are necessary for the accurate evaluation of patients and to plan intervention strategies.

  15. Relationship between manual dexterity and the unified parkinson’s disease rating scale-motor exam

    PubMed Central

    Hwang, Sujin; Song, Chiang-Soon

    2016-01-01

    [Purpose] The purpose of this study was to examine the relationships between manual dexterity and the Unified Parkinson’s Disease Rating Scale-Motor Exam as a clinical tool for quantifying upper extremity function in persons with Parkinson’s disease. [Subjects and Methods] Thirty-two persons with idiopathic Parkinson’s disease participated in this study. This study measured two clinical outcomes, the box-and-block test and the Unified Parkinson’s Disease Rating Scale-Motor Exam, to investigate the relationships between manual dexterity and the Unified Parkinson’s Disease Rating Scale-Motor Exam. [Results] The box-and-block test on the more affected side was positive relationship with the box-and-block test on the less affected side. The Unified Parkinson’s Disease Rating Scale-motor exam score had a negative correlation with the box-and-block test results for both sides. [Conclusion] A positive association was noted between manual dexterity and motor function in patients with idiopathic Parkinson disease. The results of this study suggest that the box-and-block test and the Unified Parkinson’s Disease Rating Scale-Motor Exam are good clinical measures that quantify upper extremity function and are necessary for the accurate evaluation of patients and to plan intervention strategies. PMID:28174461

  16. Assessing the Spatial Relationships Between Hydrological Processes and Catchment Architecture at Multiple Scales

    NASA Astrophysics Data System (ADS)

    Ali, G.; Roy, A.; Thériault, R.; Sicotte, K.

    2008-12-01

    New statistical tools are needed in hydrology to improve our understanding of process heterogeneity and its relationship to catchment architecture. Specifically, the issue of spatial scale must be carefully considered while investigating hydrological processes, yet it is often invoked in a qualitative (catchment, hillslope and plot scales) rather than in a quantitative manner (distance or area assessments). In this paper, we applied a new approach, the PCNM (principal coordinates of neighbor matrices) method, for the search for dominant organizing scales of soil moisture in a humid temperate forested catchment. PCNM analysis provides a way of modeling spatial patterns by a combination of auto-correlated structures. This method has proven invaluable in ecology but is still not used in hydrology. PCNM could be a very powerful tool for depicting the spatial structure of hydrological state variables, the dynamics of which usually reflect processes dependent upon spatial connectivity and stormflow distribution between heterogeneous locations. We focused on three key- questions regarding processes and scales: (1) do catchment soil moisture patterns reflect the hierarchical scales of hydrological processes?, (2) is there a strong relationship between soil moisture patterns and topographic controls patterns?, and (3) are soil moisture patterns and their topographic controls across scales highly dependent upon hydro-meteorological factors? Data consisted of 11 surveys of soil moisture content at multiple depths in the 5.1 ha Hermine catchment (Laurentians, Canada). PCNM analysis was able to dissect the variance in soil moisture over four nested scales: very-large (1.1-1.6 ha), large (0.8-1.1 ha), meso (0.1-0.8 ha) and fine (less than 0.1 ha). The technique proved to be useful in searching for characteristic spatial scales, as the PCNM model explained between 87 and 98 % of the variance in the detrended soil moisture data apportioned into significant decreasing fractions

  17. 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.

  18. Relationship between Hounsfield Unit in CT Scan and Gray Scale in CBCT.

    PubMed

    Razi, Tahmineh; Niknami, Mahdi; Alavi Ghazani, Fakhri

    2014-01-01

    Background and aims. Cone-beam computed tomography (CBCT) is an imaging system which has many advantages over computed tomography (CT). In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present study was to investigate the relationship between gray scale in CBCT) and Hounsfield Unit (HU) in CT scan. Materials and methods. In this descriptive study, the head of a sheep was scanned with 3 CBCT and one medical CT scanner. Gray scales and HUs were detected on images. Reconstructed data were analyzed to investigate relationship between CBCT gray scales and HUs. Results. A strong correlation between gray scales of CBCT and HUs of CT scan was determined. Conclusion. Considering the fact that gray scale in CBCT is the criteria in measurement of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  19. Characterizing scale-dependent community assembly using the functional-diversity--area relationship.

    PubMed

    Smith, Adam B; Sandel, Brody; Kraft, Nathan J B; Carey, Susan

    2013-11-01

    Phenotypic traits mediate organisms' interactions with the environment and determine how they affect and are affected by their biotic and abiotic milieu. Thus, dispersion of trait values, or functional diversity (FD) of a community can offer insights into processes driving community assembly. For example, underdispersion of FD suggests that habitat "filtering" of species with unfavorable trait values restricts the species that can exist in a particular habitat, while even spacing of FD suggests that interspecific competition, or biotic "sorting," discourages the coexistence of species with similar trait values. Since assembly processes are expected to vary as a function of spatial scale, we should also expect patterns of FD to reflect scale dependence in filtering and biotic sorting. Here we present the concept of the functional-diversity-area relationship (FAR), which is similar to the species-area relationship but plots a measure of phenotypic trait diversity as a function of spatial scale. We develop a set of null model tests that discriminate between FARs generated predominantly by filtering or biotic sorting and indicate the scales at which these effects are pronounced. The utility of the FAR for addressing long-standing issues in ecology is illustrated with several examples. A multi-scale examination of FD and its pattern relative to null expectations provides an important tool for ecologists interested in understanding the scale dependence of community assembly processes.

  20. 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.

  1. 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.

  2. 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

    2015-06-03

    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.

  3. Relationship Between the Functional Status Scale and the Pediatric Overall Performance Category and Pediatric Cerebral Performance Category Scales FREE

    PubMed Central

    Pollack, Murray M.; Holubkov, Richard; Funai, Tomohiko; Clark, Amy; Moler, Frank; Shanley, Thomas; Meert, Kathy; Newth, Christopher J. L.; Carcillo, Joseph; Berger, John T.; Doctor, Allan; Berg, Robert A.; Dalton, Heidi; Wessel, David L.; Harrison, Rick E.; Dean, J. Michael; Jenkins, Tammara L.

    2015-01-01

    Importance Functional status assessment methods are important as outcome measures for pediatric critical care studies. Objective To investigate the relationships between the 2 functional status assessment methods appropriate for large-sample studies, the Functional Status Scale (FSS) and the Pediatric Overall Performance Category and Pediatric Cerebral Performance Category (POPC/PCPC) scales. Design, Setting, and Participants Prospective cohort study with random patient selection at 7 sites and 8 children’s hospitals with general/medical and cardiac/cardiovascular pediatric intensive care units (PICUs) in the Collaborative Pediatric Critical Care Research Network. Participants included all PICU patients younger than 18 years. Main Outcomes and Measures Functional Status Scale and POPC/PCPC scores determined at PICU admission (baseline) and PICU discharge. We investigated the association between the baseline and PICU discharge POPC/PCPC scores and the baseline and PICU discharge FSS scores, the dispersion of FSS scores within each of the POPC/PCPC ratings, and the relationship between the FSS neurologic components (FSS-CNS) and the PCPC. Results We included 5017 patients. We found a significant (P < .001) difference between FSS scores in each POPC or PCPC interval, with an FSS score increase with each worsening POPC/PCPC rating. The FSS scores for the good and mild disability POPC/PCPC ratings were similar and increased by 2 to 3 points for the POPC/PCPC change from mild to moderate disability, 5 to 6 points for moderate to severe disability, and 8 to 9 points for severe disability to vegetative state or coma. The dispersion of FSS scores within each POPC and PCPC rating was substantial and increased with worsening POPC and PCPC scores. We also found a significant (P < .001) difference between the FSS-CNS scores between each of the PCPC ratings with increases in the FSS-CNS score for each higher PCPC rating. Conclusions and Relevance The FSS and POPC/PCPC system

  4. 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.

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

    PubMed

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

    2015-02-01

    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

  6. 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

  7. 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

  8. Estimating forest biomass using scale linkage from tree to Landsat TM reflectance data

    NASA Astrophysics Data System (ADS)

    Ung, Chhun-Huor; Lambert, Marie-Claude; Raulier, Frédéric

    2005-10-01

    Estimates of forest biomass are needed to account for carbon at the tree, stand and regional scales. Sample plots of national forest inventories provide the basic database for these estimates. At the tree scale, a common estimation method is the use of an allometric equation that relates a tree's predicted compartment biomass yi (i = foliage, branches, stem wood or stem bark) with easily obtained non-destructive measurements, i.e., diameter at breast height (D): yi=bi1Dbi2 or with both D and tree height (H): yi=bi1Dbi2Hbi3, bik being the parameters estimated. A common paradigm observed in biomass literature considers that parameter values vary between stands and regions. At the regional scale, however, when comparing national biomass equations to regional biomass equations, our results showed no significant differences between both types of equation. These results contribute to strengthening the allometric theory as an organizing principle for quantifying the relationship between tree size and biomass across spatial scales. In tandem with the allometry theory, we used a soil-canopy model based on Li-Strahler's approach for up-scaling biomass from the tree to stand scale in a mixed hardwood-coniferous forest. Our results indicated that the shadow fraction of Landsat TM reflectance was correlated with stand biomass. However, this model is indebted with heteroscedasticity, meaning that its error increases appreciably when stand biomass density is high.

  9. Do Vascular Networks Branch Optimally or Randomly across Spatial Scales?

    PubMed Central

    Newberry, Mitchell G.; Savage, Van M.

    2016-01-01

    Modern models that derive allometric relationships between metabolic rate and body mass are based on the architectural design of the cardiovascular system and presume sibling vessels are symmetric in terms of radius, length, flow rate, and pressure. Here, we study the cardiovascular structure of the human head and torso and of a mouse lung based on three-dimensional images processed via our software Angicart. In contrast to modern allometric theories, we find systematic patterns of asymmetry in vascular branching, potentially explaining previously documented mismatches between predictions (power-law or concave curvature) and observed empirical data (convex curvature) for the allometric scaling of metabolic rate. To examine why these systematic asymmetries in vascular branching might arise, we construct a mathematical framework to derive predictions based on local, junction-level optimality principles that have been proposed to be favored in the course of natural selection and development. The two most commonly used principles are material-cost optimizations (construction materials or blood volume) and optimization of efficient flow via minimization of power loss. We show that material-cost optimization solutions match with distributions for asymmetric branching across the whole network but do not match well for individual junctions. Consequently, we also explore random branching that is constrained at scales that range from local (junction-level) to global (whole network). We find that material-cost optimizations are the strongest predictor of vascular branching in the human head and torso, whereas locally or intermediately constrained random branching is comparable to material-cost optimizations for the mouse lung. These differences could be attributable to developmentally-programmed local branching for larger vessels and constrained random branching for smaller vessels. PMID:27902691

  10. 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

  11. Development and psychometric analysis of the student-teacher relationship scale - short form.

    PubMed

    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.

  12. Scaling Relationship Among Source Parameters of Microearthquake," From Near Source Observation in a Deep Mine

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Y.; Yoshimura, M.; Furumoto, M.

    2004-12-01

    Scaling relationships among various source parameters are important clues to understand the source process. In particular the relationship between the corner frequency, fC, and the seismic moment, MO, has been investigated by many researchers. Aki(1967) investigated fC and MO using the spectra of seismic waves and reported that these parameters obeyed a relationship of MO ∝ fC-3. For small earthquakes, the breakdown of this relationship was often reported. On the other hand, no breakdown of the relationship for microearthquakes has been reported from high quality observation at deep boreholes and in a deep gold mine. We report here these scaling relationships using waveform of microearthquakes observed at the distance range of 15m to 1km. We installed nine tri-axial borehole accelerometers within 200 m along a haulage tunnel 2650m deep in Mponeng mine in South Africa from February to December in 1996. More than 25 thousand seismic events were recorded with a sampling frequency of 15 kHz and a dynamic range of 120 dB. The recording system has flat response up to 2 KHz. Among those events, we select 378 events with high S/N. We locate hypocenters assuming infinite medium with the P-wave velocity 5.5 km/s and the S-wave velocity 3.2 km/s. We calculate the green function using the discrete wavenumber integral method into account the effect of anelasticity by Takeo (1985) and determine the seismic moment and the mechanism using moment tensor inversion. We apply the omega square model by Brune (1970) to determine the corner frequency and the stress drop. Minimizing L2 norm between the observed spectra of P and S waves and the synthetic ones give the optimum source parameters. The earthquakes analyzed in this study show the constant stress drop of 0.4 ˜8MPa in the ranges of 40scaled as fC-3. This result is consistent with the previous work by Ogasawara et al. (2001). Compared with other studies, the scaling

  13. 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.

  14. 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.

  15. 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.

  16. Investigating the relationship between North Atlantic Oscillation and flood losses at the European scale

    NASA Astrophysics Data System (ADS)

    Zanardo, Stefano; Jewson, Steve; Nicotina, Ludovico; Hilberts, Arno

    2016-04-01

    The North Atlantic Oscillation (NAO) is Europe's dominant mode of climate variability. As a consequence, the interconnections between NAO and hydrologic extremes in the European continent have long been observed and analysed. Some of this research has been focusing on the relationship between NAO and catastrophic floods, however, the lack of extensive data-sets restricts these studies to relatively small spatial and temporal scales. This is an obvious limitation when dealing with flood risk; indeed, the highly non-linear relationships among the different physical and anthropogenic controls are responsible for strong spatial and temporal correlations that cannot be accounted for at the local scale alone. The goal of this work is to explore the relationship between the NAO signal and economic flood losses at the European scale through long term stochastic simulations. For this study we use the European flood model recently developed by RMS (Risk Management Solution Ltd). The model combines 50000 years of rainfall-runoff-inundation simulations with a high definition exposure/vulnerability model to produce simulated flood losses in 13 European countries. The correlation between rainfall fields and NAO signal is based on the last 50 years of data and discretized at the monthly level. We found significant correlations between the NAO signal and both the average annual loss (AAL) and the average seasonal loss (ASL), for all the countries analysed. Noticeably, ASL-NAO trends were always negative for summer, spring and fall seasons, while could be either positive or negative for winter seasons, depending on the country.

  17. Bias in C IV-based quasar black hole mass scaling relationships from reverberation mapped samples

    NASA Astrophysics Data System (ADS)

    Brotherton, Michael S.; Runnoe, J. C.; Shang, Zhaohui; DiPompeo, M. A.

    2015-08-01

    The masses of the black holes powering quasars represent a fundamental parameter of active galaxies. Estimates of quasar black hole masses using single-epoch spectra are quite uncertain, and require quantitative improvement. We recently identified a correction for C IV λ1549-based scaling relationships used to estimate quasar black hole masses that relies on the continuum-subtracted peak flux ratio of the ultraviolet emission-line blend Si IV + O IV] (the λ1400 feature) to that of C IV. This parameter correlates with the suite of associated quasar spectral properties collectively known as `Eigenvector 1' (EV1). Here we use a sample of 85 quasars with quasi-simultaneous optical-ultraviolet spectrophotometry to demonstrate how biases in the average EV1 properties can create systematic biases in C IV-based black hole mass scaling relationships. This effect results in nearly an order of magnitude moving from objects with small , which have overestimated black hole masses, to objects with large , which have underestimated values. We show that existing reverberation-mapped samples of quasars with ultraviolet spectra - used to calibrate C IV-based scaling relationships - have significant EV1 biases that result in predictions of black hole masses nearly 50 per cent too high for the average quasar. We offer corrections and suggestions to account for this bias.

  18. A revision of the sexual coercion in intimate relationships scale for young adults in China.

    PubMed

    He, Shanshan; Tsang, Sandra; Li, Caina

    2013-01-01

    The Sexual Coercion in Intimate Relationships Scale (SCIRS; 34 items) assesses the severity of sexual coercion (SC) in committed intimate relationships, but it does not validly screen out valid target cases or accurately assess prevalence. This study aims to revise the SCIRS to facilitate research in China. There were 927 college students in active dating relationships, from 5 large Chinese cities, who participated in the study. The results showed that the revised SCIRS (33 items) measured 3 constructs-Emotional Manipulation (17 items), Defection Threat (7 items), and Violence Threat (7 items)-and that the reliability and validity properties were satisfactory. The advantages of the revision and the limitations of this study are discussed.

  19. 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.

  20. Scaling relationships and physics for mixed heating convection in planetary interiors: Isoviscous spherical shells

    NASA Astrophysics Data System (ADS)

    Weller, Matthew B.; Lenardic, Adrian; Moore, William B.

    2016-10-01

    We use a suite of 3-D numerical experiments to test and expand 2-D planar isoviscous scaling relationships of Moore (2008) for mixed heating convection in spherical geometry mantles over a range of Rayleigh numbers (Ra). The internal temperature scaling of Moore (2008), when modified to account for spherical geometry, matches our experimental results to a high degree of fit. The heat flux through the boundary layers scale as a linear combination of internal (Q) and basal heating, and the modified theory predictions match our experimental results. Our results indicate that boundary layer thickness and surface heat flux are not controlled by a local boundary layer stability condition (in agreement with the results of Moore (2008)) and are instead strongly influenced by boundary layer interactions. Subadiabatic mantle temperature gradients, in spherical 3-D, are well described by a vertical velocity scaling based on discrete drips as opposed to a scaling based on coherent sinking sheets, which was found to describe 2-D planar results. Root-mean-square (RMS) velocities are asymptotic for both low Q and high Q, with a region of rapid adjustment between asymptotes for moderate Q. RMS velocities are highest in the low Q asymptote and decrease as internal heating is applied. The scaling laws derived by Moore (2008), and extended here, are robust and highlight the importance of differing boundary layer processes acting over variable Q and moderate Ra.

  1. Spanish and English neuropsychological assessment scales: relationship to demographics, language, cognition, and independent function.

    PubMed

    Mungas, Dan; Reed, Bruce R; Haan, Mary N; González, Hector

    2005-07-01

    This study examined the relationship of the Spanish and English Neuropsychological Assessment Scales (SENAS) to demographic, cultural, and language fluency variables and to measures of cognition and independent functioning. Participants were 367 Hispanics and 160 Caucasians in the 60+ years age range, all living in the community. In Study 1, education and language use had strong influences on SENAS scores and largely explained ethnic group differences in mean scale scores. Age had weak effects on most scales except for verbal memory measures. Acculturation effects in Hispanics were largely accounted for by education and language use. Study 2 showed equivalent sensitivity of SENAS to cognitive and functional status in Hispanics and Caucasians. Results indicate that interpretation of SENAS scores must be informed by effects related to education and language fluency but provide evidence of equivalent validity in Hispanics and Caucasians with respect to concurrent measures of cognition and independent function.

  2. A Portuguese version of the student-teacher relationship scale - short form.

    PubMed

    Patrício, Joana Nunes; Barata, M Clara; Calheiros, M Manuela; Graça, João

    2015-05-20

    Research consistently demonstrates that positive student-teacher relationships are fundamental to the healthy development of all students. However, we lack a Portuguese-validated measure of student-teacher relationships. In this article we present the adaptation procedures and the psychometric properties of a Portuguese version of the Student-Teacher Relationship Scale - Short Form (Pianta, 1992). Five hundred and thirty five teachers from 127 schools completed the STRS-SF. The results demonstrate that this adapted version of the STRS-SF has good psychometric properties, namely high reliability (α = .84 to .87) and expected construct validity, which were tested through exploratory and confirmatory factor analyses (χ2/df = 1.65, CFI = .96, GFI = .93, RMSEA = 0.05). This study also showed that the correlations of student-teacher relationship with students' demographic variables are consistent with the evidence in the literature about this construct. Finally, the study indicated that female teachers reported more closeness, t(530) = 4.06, p < .001 and better overall student-teacher relationships, t(530) = 4.90, p < .001. In the discussion, we analyze the implications of these results.

  3. 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.

  4. 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.

  5. To scale or not to scale: the principles of dose extrapolation

    PubMed Central

    Sharma, Vijay; McNeill, John H

    2009-01-01

    The principles of inter-species dose extrapolation are poorly understood and applied. We provide an overview of the principles underlying dose scaling for size and dose adjustment for size-independent differences. Scaling of a dose is required in three main situations: the anticipation of first-in-human doses for clinical trials, dose extrapolation in veterinary practice and dose extrapolation for experimental purposes. Each of these situations is discussed. Allometric scaling of drug doses is commonly used for practical reasons, but can be more accurate when one takes into account species differences in pharmacokinetic parameters (clearance, volume of distribution). Simple scaling of drug doses can be misleading for some drugs; correction for protein binding, physicochemical properties of the drug or species differences in physiological time can improve scaling. However, differences in drug transport and metabolism, and in the dose–response relationship, can override the effect of size alone. For this reason, a range of modelling approaches have been developed, which combine in silico simulations with data obtained in vitro and/or in vivo. Drugs that are unlikely to be amenable to simple allometric scaling of their clearance or dose include drugs that are highly protein-bound, drugs that undergo extensive metabolism and active transport, drugs that undergo significant biliary excretion (MW > 500, ampiphilic, conjugated), drugs whose targets are subject to inter-species differences in expression, affinity and distribution and drugs that undergo extensive renal secretion. In addition to inter-species dose extrapolation, we provide an overview of dose extrapolation within species, discussing drug dosing in paediatrics and in the elderly. PMID:19508398

  6. 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.…

  7. Statistical relationship between large-scale upward field-aligned currents and electron precipitation

    NASA Astrophysics Data System (ADS)

    Korth, Haje; Zhang, Yongliang; Anderson, Brian J.; Sotirelis, Thomas; Waters, Colin L.

    2014-08-01

    Simultaneous observations of Birkeland currents by the constellation of Iridium satellites and N2 Lyman-Birge-Hopfield (LBH) auroral emissions measured by the Global Ultraviolet Imager (GUVI) onboard the Thermosphere, Ionosphere, and Mesosphere Energetics and Dynamics (TIMED) satellite are used to establish relationships between large-scale upward field-aligned currents and electron precipitation during stable current configurations. The electron precipitation was inferred from GUVI data using a statistical relationship between LBH intensity and electron energy flux. LBH emissions with >5% contribution from protons, identified by Lyman-alpha intensity, were excluded from the analysis. The Birkeland currents were derived with a spatial resolution of 3° in latitude and 2 h in local time. For southward interplanetary magnetic field (IMF), the electron precipitation occurred primarily within and near large-scale upward currents. The correspondence was less evident for northward IMF, presumably because the spatial variability is large compared to the areas of interest so that the number of events identified is smaller and the derived statistical distributions are less reliable. At dusk, the correlation between upward current and precipitation was especially high, where a larger fraction of the electron precipitation is accelerated downward by a field-aligned potential difference. Unaccelerated electron precipitation dominated in the morning sector, presumably induced by scattering of eastward-drifting energetic electrons into the loss cone through interaction with whistler-mode waves (diffuse precipitation) rather than by field-aligned acceleration. In the upward Region 1 on the dayside, where the electron precipitation is almost exclusively due to field-aligned acceleration, a quadratic relationship between current density and electron energy flux was observed, implying a linear current-voltage relationship in this region. Current density and electron energy flux in

  8. Understanding Monthly Land Surface Relationships at the Continental Scale Using Remotely Sensed Data

    NASA Astrophysics Data System (ADS)

    Robertson, R. D.; Mehra, V.; Kumar, P.; Bajcsy, P.; Tcheng, D.

    2006-12-01

    In the past few decades, remotely sensed Earth observation data has been gathered at rates now on the order of tens of terabytes per day. These collections of data are valuable reserves of "scientific ore." However, mining the ore for useful science has been challenging due to the sheer volume of data, esoteric formats, varying temporal scales, and varying spatial scales. Regardless, the wide geographic and temporal ranges allow investigations at scales inaccessible by other presently existing methods. We developed a technology called GeoLearn to facilitate data preparation and basic exploration so this data can be more readily available for scientific purposes. GeoLearn is used to prepare the data which we examine for relationships between several land surface variables across the entire continental USA during each month in the summer of 2004. We employ two approaches: k-means style clustering and regression tree approaches. Using k-means, we try to identify geographic regions of similarity using only remotely sensed characteristics. The resulting geographic regions often, but not always, correspond to EPA ecoregion boundaries. Using regressions trees, we try to predict a greenness index (EVI) based on other characteristics. In this case, the differing resolutions of the datasets became important. EVI is the most detailed variable we use. Since regression trees are capable of quite detailed approximations, the best naive model turns out to be based on the one or two most detailed explanatory variables. This results in a model which merely uses the explanatory variables as ID numbers rather than identifying any general relationships. We are able to develop alternative models which maintain flexibility without succumbing to the "ID number" problem as easily. These models allow us to identify what variables are most important for determining vegetation greenness at continental scales as well as how those relationships changed throughout the summer of 2004.

  9. 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).

  10. 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.

  11. 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.

  12. The Neighborhood Environment Walkability Scale for the Republic of Korea: Reliability and Relationship with Walking

    PubMed Central

    KIM, Hyunshik; CHOI, Younglae; MA, Jiameng; HYUNG, Kuam; MIYASHITA, Masashi; LEE, Sunkyoung

    2016-01-01

    Background: The aim of the study was to analyze the reliability of the Korean version of the NEWS and to investigate the relationship between walking and environmental factors by gender. Methods: A total of 1407 Korean adults, aged 20–59 yr, participated in the study. Data were collected between Sep 2013 and Oct 2013. To examine the test-retest reliability, 281 of the 1407 participants were asked to answer the same questionnaire (Korean NEWS-A scale) after a 7-d interval. Results: The ICC range of the entire questionnaire was 0.71–0.88. The item on land use mix-diversity had the highest ICC, and that on physical barriers had the lowest. In addition, presents the partial correlation coefficients for walking and the NEWS-A score, adjusted for social demographic variables. Overall, land use mix-diversity (P<0.034) and land use mix-access (P<0.014) showed a positive relationship with walking. Discussion: Examination of the reliability of the Korean NEWS-A scale based on Korean adults who reside in large cities showed that all items had statistically satisfactory reliability. Korean NEWS-A scale may be a useful measure for assessing environmental correlates of walking among population in Korea. PMID:28032060

  13. Scale Effects on Spatially Varying Relationships Between Urban Landscape Patterns and Water Quality

    NASA Astrophysics Data System (ADS)

    Sun, Yanwei; Guo, Qinghai; Liu, Jian; Wang, Run

    2014-08-01

    Scientific interpretation of the relationships between urban landscape patterns and water quality is important for sustainable urban planning and watershed environmental protection. This study applied the ordinary least squares regression model and the geographically weighted regression model to examine the spatially varying relationships between 12 explanatory variables (including three topographical factors, four land use parameters, and five landscape metrics) and 15 water quality indicators in watersheds of Yundang Lake, Maluan Bay, and Xinglin Bay with varying levels of urbanization in Xiamen City, China. A local and global investigation was carried out at the watershed-level, with 50 and 200 m riparian buffer scales. This study found that topographical features and landscape metrics are the dominant factors of water quality, while land uses are too weak to be considered as a strong influential factor on water quality. Such statistical results may be related with the characteristics of land use compositions in our study area. Water quality variations in the 50 m buffer were dominated by topographical variables. The impact of landscape metrics on water quality gradually strengthen with expanding buffer zones. The strongest relationships are obtained in entire watersheds, rather than in 50 and 200 m buffer zones. Spatially varying relationships and effective buffer zones were verified in this study. Spatially varying relationships between explanatory variables and water quality parameters are more diversified and complex in less urbanized areas than in highly urbanized areas. This study hypothesizes that all these varying relationships may be attributed to the heterogeneity of landscape patterns in different urban regions. Adjustment of landscape patterns in an entire watershed should be the key measure to successfully improving urban lake water quality.

  14. Relationships between human population density and burned area at continental and global scales.

    PubMed

    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.

  15. 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.

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

    PubMed

    Passarelli, L; Rivalta, E; Shuler, A

    2014-01-28

    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.

  17. Systematic perturbation of cytoskeletal function reveals a linear scaling relationship between cell geometry and fitness.

    PubMed

    Monds, Russell D; Lee, Timothy K; Colavin, Alexandre; Ursell, Tristan; Quan, Selwyn; Cooper, Tim F; Huang, Kerwyn Casey

    2014-11-20

    Diversification of cell size is hypothesized to have occurred through a process of evolutionary optimization, but direct demonstrations of causal relationships between cell geometry and fitness are lacking. Here, we identify a mutation from a laboratory-evolved bacterium that dramatically increases cell size through cytoskeletal perturbation and confers a large fitness advantage. We engineer a library of cytoskeletal mutants of different sizes and show that fitness scales linearly with respect to cell size over a wide physiological range. Quantification of the growth rates of single cells during the exit from stationary phase reveals that transitions between "feast-or-famine" growth regimes are a key determinant of cell-size-dependent fitness effects. We also uncover environments that suppress the fitness advantage of larger cells, indicating that cell-size-dependent fitness effects are subject to both biophysical and metabolic constraints. Together, our results highlight laboratory-based evolution as a powerful framework for studying the quantitative relationships between morphology and fitness.

  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.

  20. 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

  1. Allometric comparison of skulls from two closely related weasels, Mustela itatsi and M. sibirica.

    PubMed

    Suzuki, Satoshi; Abe, Mikiko; Motokawa, Masaharu

    2011-09-01

    We conducted an interspecific comparison of skulls from two closely related but differently sized mustelid species, Mustela itatsi and M. sibirica (Mammalia, Carnivora, Mustelidae); a sexual comparison within the latter species showed remarkable size dimorphism. We clarified several differences in skull proportion related to size using allometric analyses and qualitative comparisons. Allometric analysis revealed that the skulls of male M. itatsi (the smaller species) have a relatively long palate; a slender viscerocranium and postorbital constriction; a broad, short, and low neurocranium; small carnassials; and a short mandible with a thin body and small ramus compared to the skulls of male M. sibirica (the larger species). Similar results were obtained when male M. itatsi were compared to female M. sibirica, although the male M. itatsi had a broader viscerocranium than female M. sibirica. A sexual comparison in M. sibirica revealed a larger skull size among the males with a relatively wide viscerocranium; wide postorbital constriction; a slender, long, and high neurocranium; short and wide auditory bullae; short carnassials; and a long and high mandible compared to females. Qualitative comparisons revealed changes in a few characters depending on skull size or with respect to some cranial components in each species. The interspecific differences observed were clearly larger than the intraspecific differences for three qualitative characters. The allometric and qualitative differences detected between these species suggest that each species is not simply the dwarf and/or giant morph of the other, and complicated differences were clarified.

  2. 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.

  3. 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

  4. Relationship between fine-mode AOD and precipitation on seasonal and interannual time scales

    NASA Astrophysics Data System (ADS)

    Jeoung, Hwayoung; Chung, Chul E.; van Noije, Twan; Takemura, Toshihiko

    2014-05-01

    On seasonal and interannual time scales, weather is highly influential in aerosol variability. In this study, we investigate the relationship between fine-mode AOD (fAOD) and precipitation on these scales, in order to unravel the effect of wet weather on aerosol amount. We find with integrated satellite and ground observations that biomass burning related fAOD has a relatively greater seasonal variation than fossil fuel combustion related fAOD. It is also found that wet weather reduces biomass burning fAOD and increases fossil-fuel combustion fAOD. Aerosol simulation models forced by reanalyses consistently simulate the biomass burning fAOD reduced during wet weather but only in the tropics and furthermore do not consistently increase fossil-fuel combustion fAOD during wet conditions. The identified relationship between fAOD and precipitation in observations allows for seasonal predictability of fAOD, since average precipitation can be predicted a few to several months in advance due to the well-established predictability of ENSO. We reveal ENSO-covariant fAOD using a rotated component principal analysis of combined interannual variation of SST, precipitation and fAOD. During the warm phase of ENSO, we find that fAOD increases over Indonesia and the eastern coastal area of China, and decreases over South Asia, the Amazon and the continental parts of China.

  5. Whole muscle length-tension relationships are accurately modeled as scaled sarcomeres in rabbit hindlimb muscles.

    PubMed

    Winters, Taylor M; Takahashi, Mitsuhiko; Lieber, Richard L; Ward, Samuel R

    2011-01-04

    An a priori model of the whole active muscle length-tension relationship was constructed utilizing only myofilament length and serial sarcomere number for rabbit tibialis anterior (TA), extensor digitorum longus (EDL), and extensor digitorum II (EDII) muscles. Passive tension was modeled with a two-element Hill-type model. Experimental length-tension relations were then measured for each of these muscles and compared to predictions. The model was able to accurately capture the active-tension characteristics of experimentally-measured data for all muscles (ICC=0.88 ± 0.03). Despite their varied architecture, no differences in predicted versus experimental correlations were observed among muscles. In addition, the model demonstrated that excursion, quantified by full-width-at-half-maximum (FWHM) of the active length-tension relationship, scaled linearly (slope=0.68) with normalized muscle fiber length. Experimental and theoretical FWHM values agreed well with an intraclass correlation coefficient of 0.99 (p<0.001). In contrast to active tension, the passive tension model deviated from experimentally-measured values and thus, was not an accurate predictor of passive tension (ICC=0.70 ± 0.07). These data demonstrate that modeling muscle as a scaled sarcomere provides accurate active functional but not passive functional predictions for rabbit TA, EDL, and EDII muscles and call into question the need for more complex modeling assumptions often proposed.

  6. 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.

  7. Changes of scaling relationships in an evolving population: The example of "sedimentary" stylolites

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Korneva, I.; Nixon, C. W.; Rotevatn, A.

    2017-03-01

    Bed-parallel (;sedimentary;) stylolites are used as an example of a population that evolves by the addition of new components, their growth and their merger. It is shown that this style of growth controls the changes in the scaling relationships of the population. Stylolites tend to evolve in carbonate rocks through time, for example by compaction during progressive burial. The evolution of a population of stylolites, and their likely effects on porosity, are demonstrated using simple numerical models. Starting with a power-law distribution, the adding of new stylolites, the increase in their amplitudes and their merger decrease the slope of magnitude versus cumulative frequency of the population. The population changes to a non-power-law distribution as smaller stylolites merge to form larger stylolites. The results suggest that other populations can be forward- or backward-modelled, such as fault lengths, which also evolve by the addition of components, their growth and merger. Consideration of the ways in which populations change improves understanding of scaling relationships and vice versa, and would assist in the management of geofluid reservoirs.

  8. 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.

  9. 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…

  10. 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

  11. The consistency and stability of abundance-occupancy relationships in large-scale population dynamics.

    PubMed

    Zuckerberg, Benjamin; Porter, William F; Corwin, Kimberley

    2009-01-01

    1. Abundance-occupancy relationships comprise some of the most general and well-explored patterns in macro-ecology. The theory governing these relationships predicts that species will exhibit a positive interspecific and intraspecific relationship between regional occupancy and local abundance. Abundance-occupancy relationships have important implications in using distributional surveys, such as atlases, to understand and document large-scale population dynamics and the consequences of environmental change. A basic need for interpreting such data bases is a better understanding of whether changes in regional occupancy reflect changes in local abundance across species of varying life-history characteristics. 2. Our objective was to test the predictions of the abundance-occupancy rule using two independent data sets, the New York State Breeding Bird Atlas and the North American Breeding Bird Survey. The New York State Breeding Bird Atlas consists of 5332 25-km(2) survey blocks and is one of the first atlases in the USA to be completed for two time periods (1980-85 and 2000-05). The North American Breeding Survey is a large-scale annual survey intended to document the relative abundance and population change of songbirds throughout the USA. 3. We found that regional occupancy was positively correlated with relative abundance across 98 (beta = 0.60 +/- 0.11 SE, P < 0.001, R(2) = 0.60) and 85 species (beta = 0.67 +/- 0.06 SE, P < 0.001, R(2) = 0.57) in two separate time periods. This relationship proved stable over time and was notably consistent between breeding habitat groups and migratory guilds. 4. Between 1980 and 2005, changes in regional occupancy were highly correlated with long-term abundance trend estimates for 75 species (beta = 5.73 +/- 0.24 SE, P < 0.001, R(2) = 0.88). Over a 20-year period, woodland and resident birds showed an increase in occupancy while grassland species showed the greatest decline; these patterns were mirrored by changes in local

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

    PubMed

    Storch, David; Keil, Petr; Jetz, Walter

    2012-08-02

    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.

  13. Development of magnitude scaling relationship for earthquake early warning system in South Korea

    NASA Astrophysics Data System (ADS)

    Sheen, D.

    2011-12-01

    Seismicity in South Korea is low and magnitudes of recent earthquakes are mostly less than 4.0. However, historical earthquakes of South Korea reveal that many damaging earthquakes had occurred in the Korean Peninsula. To mitigate potential seismic hazard in the Korean Peninsula, earthquake early warning (EEW) system is being installed and will be operated in South Korea in the near future. In order to deliver early warnings successfully, it is very important to develop stable magnitude scaling relationships. In this study, two empirical magnitude relationships are developed from 350 events ranging in magnitude from 2.0 to 5.0 recorded by the KMA and the KIGAM. 1606 vertical component seismograms whose epicentral distances are within 100 km are chosen. The peak amplitude and the maximum predominant period of the initial P wave are used for finding magnitude relationships. The peak displacement of seismogram recorded at a broadband seismometer shows less scatter than the peak velocity of that. The scatters of the peak displacement and the peak velocity of accelerogram are similar to each other. The peak displacement of seismogram differs from that of accelerogram, which means that two different magnitude relationships for each type of data should be developed. The maximum predominant period of the initial P wave is estimated after using two low-pass filters, 3 Hz and 10 Hz, and 10 Hz low-pass filter yields better estimate than 3 Hz. It is found that most of the peak amplitude and the maximum predominant period are estimated within 1 sec after triggering.

  14. The Relationship between the Overcontrolled-Hostility Scale and the MMPI 4-3 High-Point Pair.

    ERIC Educational Resources Information Center

    Walters, Glenn D.; And Others

    1982-01-01

    Investigated the relationship between the Minnesota Multiphasic Personality Inventory 4-3 high-point pair and the Overcontrolled-Hostility (O-H) scale in prisoners, psychology clinic outpatients, and inpatients at a state hospital. Results suggested the O-H scale and the 4-3 high-point pair are correlated and seem to measure the same types of…

  15. Modeling Allometric Relationships in Leaves of Young Rapeseed (Brassica napus L.) Grown at Different Temperature Treatments

    PubMed Central

    Tian, Tian; Wu, Lingtong; Henke, Michael; Ali, Basharat; Zhou, Weijun; Buck-Sorlin, Gerhard

    2017-01-01

    Functional–structural plant modeling (FSPM) is a fast and dynamic method to predict plant growth under varying environmental conditions. Temperature is a primary factor affecting the rate of plant development. In the present study, we used three different temperature treatments (10/14°C, 18/22°C, and 26/30°C) to test the effect of temperature on growth and development of rapeseed (Brassica napus L.) seedlings. Plants were sampled at regular intervals (every 3 days) to obtain growth data during the length of the experiment (1 month in total). Total leaf dry mass, leaf area, leaf mass per area (LMA), width-length ratio, and the ratio of petiole length to leaf blade length (PBR), were determined and statistically analyzed, and contributed to a morphometric database. LMA under high temperature was significantly smaller than LMA under medium and low temperature, while leaves at high temperature were significantly broader. An FSPM of rapeseed seedlings featuring a growth function used for leaf extension and biomass accumulation was implemented by combining measurement with literature data. The model delivered new insights into growth and development dynamics of winter oilseed rape seedlings. The present version of the model mainly focuses on the growth of plant leaves. However, future extensions of the model could be used in practice to better predict plant growth in spring and potential cold damage of the crop. PMID:28377775

  16. Variations in normal color vision. VII. Relationships between color naming and hue scaling.

    PubMed

    Emery, Kara J; Volbrecht, Vicki J; Peterzell, David H; Webster, Michael A

    2017-01-05

    A longstanding and unresolved question is how observers construct a discrete set of color categories to partition and label the continuous variations in light spectra, and how these categories might reflect the neural representation of color. We explored the properties of color naming and its relationship to color appearance by analyzing individual differences in color-naming and hue-scaling patterns, using factor analysis of individual differences to identify separate and shared processes underlying hue naming (labeling) and hue scaling (color appearance). Observers labeled the hues of 36 stimuli spanning different angles in cone-opponent space, using a set of eight terms corresponding to primary (red, green, blue, yellow) or binary (orange, purple, blue-green, yellow-green) hues. The boundaries defining different terms varied mostly independently, reflecting the influence of at least seven to eight factors. This finding is inconsistent with conventional color-opponent models in which all colors derive from the relative responses of underlying red-green and blue-yellow dimensions. Instead, color categories may reflect qualitatively distinct attributes that are free to vary with the specific spectral stimuli they label. Inter-observer differences in color naming were large and systematic, and we examined whether these differences were associated with differences in color appearance by comparing the hue naming to color percepts assessed by hue scaling measured in the same observers (from Emery et al., 2017). Variability in both tasks again depended on multiple (7 or 8) factors, with some Varimax-rotated factors specific to hue naming or hue scaling, but others common to corresponding stimuli for both judgments. The latter suggests that at least some of the differences in how individuals name or categorize color are related to differences in how the stimuli are perceived.

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

    PubMed

    Gächter, Simon; Starmer, Chris; Tufano, Fabio

    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.

  18. Allometric scaling of production and life-history variation in vascular plants

    NASA Astrophysics Data System (ADS)

    Enquist, Brian J.; West, Geoffrey B.; Charnov, Eric L.; Brown, James H.

    1999-10-01

    A prominent feature of comparative life histories is the well documented negative correlation between growth rate and life span. Patterns of resource allocation during growth and reproduction reflect life-history differences between species. This is particularly striking in tropical forests, where tree species can differ greatly in their rates of growth and ages of maturity but still attain similar canopy sizes. Here we provide a theoretical framework for relating life-history variables to rates of production, dM/dt, where M is above-ground mass and t is time. As metabolic rate limits production as an individual grows, dM/dt ~ M3/4. Incorporating interspecific variation in resource allocation to wood density, we derive a universal growth law that quantitatively fits data for a large sample of tropical tree species with diverse life histories. Combined with evolutionary life-history theory, the growth law also predicts several qualitative features of tree demography and reproduction. This framework also provides a general quantitative answer to why relative growth rate (1/M)(dM/df) decreases with increasing plant size (~M-1/4) and how it varies with differing allocation strategies.

  19. Relationship between the Berg Balance Scale and Static Balance Test in Hemiplegic Patients with Stroke.

    PubMed

    Suzuki, Makoto; Fujisawa, Hiroyuki; Machida, Yooichiro; Minakata, Shin

    2013-08-01

    [Purpose] The purpose of this study was to analyze the relationship between results of the Berg Balance Scale (BBS) and Static Balance Test (SBT) in hemiplegic patients with stroke. [Subjects] The subjects were 39 hemiplegic patients (25 men, 14 women; mean age, 69.4 ± 11.0 years) with stroke that had occurred within the preceding 6 months and who had good understanding of verbal instructions. [Methods] The SBT consists of five posture-holding tasks (sitting, stride standing, close standing, one-foot standing on the unparalyzed leg, and one-foot standing on the paralyzed leg). Four grades, 1-4, are used to judge the ability of patients to hold these postures. The SBT and BBS were each implemented, and the relationship between test results was analyzed using correlation coefficients. [Results] The correlation coefficient for the BBS score and SBT score was 0.87. Thus, a strong correlation was seen between the BBS and SBT. [Conclusion] The SBT is thought to be an assessment index that can predict overall balance ability.

  20. A Study of the Relationship Between Freshwater Runoff and Benthos Abundance: a Scale-oriented Approach

    NASA Astrophysics Data System (ADS)

    Ardisson, P.-L.; Bourget, E.

    1997-10-01

    In some coastal environments, freshwater runoff is one of the main potential sources of auxiliary energy. Little is known, however, about the mechanisms by which this energy input influences biological production, particularly at intermediate and high trophic levels. Moreover, the evidence available does not allow to link runoff variability one unambiguously to the dynamics of marine fauna. Here, an empirical approach based on exploratory data analysis is used to test for a link between these components of the ecosystem. Linear regression and correlation models were used to examine the relationship between runoff and abundance, biomass and mean weight per individual of juvenile populations (<1 year old) of five dominant epibenthic species sampled on suspended collectors (i.e. Obelia longissima, Hiatella arctica, Mytilus edulis, Semibalanus balanoidesand Balanus crenatus), over a 10-year period. The study was carried out in a large coastal ecosystem, the Estuary and north-western Gulf of St. Lawrence, for both regulated and non-regulated runoff situations. Notwithstanding the regression or correlation model, the spatial scale, the runoff signal, the runoff index, the species or the biological descriptor used, no significant relationships were observed. Results are discussed in light of current hypotheses proposed to account for the effects of runoff on marine fauna.

  1. The effect of quantitative feed restriction on allometric growth in broilers.

    PubMed

    van der Klein, S A S; Silva, F A; Kwakkel, R P; Zuidhof, M J

    2017-01-01

    Feed restriction in broilers is aimed at preventing metabolic disorders, increasing feed efficiency, or manipulating carcass conformation. The purpose of the current study was to investigate the effects of modest graded levels feed restriction during the second and third wk of life. Mixed-sex chickens were raised in pens with 4 replications per treatment to 35 d of age. Chickens were fed ad libitum throughout the trial, or 90, 80, or 70% of expected ad libitum feed intake during the second wk of life, or 95, 90, 85, or 80% of expected ad libitum feed intake during the third wk of life. Feed intake, BW, ADG, and feed conversion ratio (FCR) were measured and weekly dissections were conducted to characterize allometric growth of the breast muscle, legs, abdominal fat pad, liver, gastro-intestinal tract (GIT), and heart. Feeding 70% of ad libitum during wk 2 and 80% during wk 3 reduced ADG during the restriction period and reduced BW at the end of the restriction period, but chickens exhibited complete compensatory growth within one wk after the restriction period. No significant effects of restriction treatment were found on BW, FCR, fat pad, empty GIT, breast muscle, heart, legs, and liver weight at d 35, but allometric growth curve for breast muscle was lower in birds fed 80 and 85% of ad libitum during wk 3, and for birds fed 70% of ad libitum in wk 2. Allometric growth curves for all body parts were different between males and females, except for the liver. Females had higher relative fat pad, breast muscle, and liver weight and a lower GIT and heart and leg weight compared with males at d 35. Feed restriction could differentially affect males and females. This study showed that feeding 70% of ad libitum in wk 2 might be beneficial to reduce fat pad, but later feed restriction in wk 3 may reduce breast muscle weight at broiler processing age.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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

  7. Allometric analysis of a morphological anti-predator trait in geographic populations of Japanese crucian carp

    PubMed Central

    Kodama, Sakie; Fujimori, Hiroka; Hakoyama, Hiroshi

    2017-01-01

    Costly anti-predator traits tend to be expressed only in high-predation conditions. For the cyprinid fish genus Carassius, deeper body depth is more adaptive to avoid predation by gape-limited piscivorous fish, but it raises swimming costs. It is therefore predicted that the relative body depth will decrease when the prey fish has reached a size larger than the predator gape-size. This prediction was tested by allometric analysis of the relation between body depth and standard length of triploid asexual females of the Japanese crucian carp (Carassius auratus sspp.) sampled from 13 geographic populations. The overall allometric relation was not significantly different from isometry. The estimate of the common major-axis slope was close to 1 (near-isometry). The mean relative body depth differed significantly among populations. A significant positive correlation was found with the mean annual air temperature. The geographic variation suggests that local selection pressures vary. In conclusion, the hypothesis that larger fish will have lower body depth was not supported, perhaps indicating that deep body depth in large fish is adaptive for some reason other than defense against piscivorous fish. PMID:28150742

  8. 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.

  9. Scaling relationships between sizes of nucleation regions and eventual sizes of microearthquakes

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Yoshihiro; Furumoto, Muneyoshi

    2007-10-01

    We investigate the initial rupture process of microearthquakes to reveal relationships between nucleation region sizes and eventual earthquake sizes. In order to obtain high quality waveform data, we installed a trigger recording system with a sampling frequency of 10 kHz at the base of a deep borehole at the Nojima Fault, Japan. We analyze waveform data of 31 events around the borehole, with seismic moment ranging from 4.2 × 10 9 Nm to 7.1 × 10 11 Nm. We use both a circular crack model with an accelerating rupture velocity (SK model) [Sato, T., Kanamori, H., 1999. Beginning of earthquakes modeled with the Griffith's fracture criterion, Bull. Seism. Soc. Am., 89, 80-93.], which generates a slow initial phase of velocity pulse, and a circular crack model with a constant rupture velocity (SH model) [Sato, T, Hirasawa, T., 1973. Body wave spectra from propagating shear cracks, J. Phys. Earth, 21, 415-431.], which generates a ramp-like velocity pulse. Source parameters of these two models are estimated by waveform inversion of the first half cycle of the observed velocity pulse applying both a grid search and a non-linear least squares method. 14 of 31 events are never reproduced by the SH model with a constant Q operator. But SK model with a constant Q operator provides a size of the pre-existing crack, corresponding to the size of the nucleation regions, and a size of the eventual crack. We recognize that (i) the eventual seismic moment is approximately scaled as the cube of the size of pre-existing cracks, (ii) the eventual seismic moment is scaled as the cube of the size of eventual cracks, and (iii) the size of eventual cracks is roughly proportional to the size of pre-existing cracks. We, thus, conclude that the size of eventual earthquakes is controlled by the size of the nucleation regions.

  10. 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.

  11. Observed and Aogcm Simulated Relationships Between us Wind Speeds and Large Scale Modes of Climate Variability

    NASA Astrophysics Data System (ADS)

    Schoof, J. T.; Pryor, S. C.; Barthelmie, R. J.

    2013-12-01

    Previous research has indicated that large-scale modes of climate variability, such as El Niño - Southern Oscillation (ENSO), the Arctic Oscillation (AO) and the Pacific-North American pattern (PNA), influence the inter-annual and intra-annual variability of near-surface and upper-level wind speeds over the United States. For example, we have shown that rawinsonde derived wind speeds indicate that 90th percentile of wind speeds at 700 hPa over the Pacific Northwest and Southwestern USA are significantly higher under the negative phase of the PNA, and the Central Plains experiences higher wind speeds at 850 hPa under positive phase Southern Oscillation index while the Northeast exhibits higher wind speeds at 850 hPa under positive phase NAO. Here, we extend this research by further investigating these relationships using both reanalysis products and output from coupled atmosphere-ocean general circulation models (AOGCMs) developed for the 5th Phase of the Coupled Model Intercomparison Project (CMIP5). The research presented has two specific goals. First, we evaluate the AOGCM simulations in terms of their ability to represent the temporal and spatial representations of ENSO, the AO, and the PNA pattern relative to historical observations. The diagnostics used include calculation of the power spectra (and thus representation of the fundamental frequencies of variability) and Taylor diagrams (for comparative assessment of the spatial patterns and their intensities). Our initial results indicate that most AOGCMs produce modes that are qualitatively similar to those observed, but that differ slightly in terms of the spatial pattern, intensity of specific centers of action, and variance explained. Figure 1 illustrates an example of the analysis of the frequencies of variability of two climate modes for the NCEP-NCAR reanalysis (NNR) and a single AOGCM (BCC CSM1). The results show a high degree of similarity in the power spectra but for this AOGCM the variance of the PNA

  12. Allometric constraints on, and trade-offs in, belowground carbon allocation and their control of soil respiration across global forest ecosystems.

    PubMed

    Chen, Guangshui; Yang, Yusheng; Robinson, David

    2014-05-01

    To fully understand how soil respiration is partitioned among its component fluxes and responds to climate, it is essential to relate it to belowground carbon allocation, the ultimate carbon source for soil respiration. This remains one of the largest gaps in knowledge of terrestrial carbon cycling. Here, we synthesize data on gross and net primary production and their components, and soil respiration and its components, from a global forest database, to determine mechanisms governing belowground carbon allocation and their relationship with soil respiration partitioning and soil respiration responses to climatic factors across global forest ecosystems. Our results revealed that there are three independent mechanisms controlling belowground carbon allocation and which influence soil respiration and its partitioning: an allometric constraint; a fine-root production vs. root respiration trade-off; and an above- vs. belowground trade-off in plant carbon. Global patterns in soil respiration and its partitioning are constrained primarily by the allometric allocation, which explains some of the previously ambiguous results reported in the literature. Responses of soil respiration and its components to mean annual temperature, precipitation, and nitrogen deposition can be mediated by changes in belowground carbon allocation. Soil respiration responds to mean annual temperature overwhelmingly through an increasing belowground carbon input as a result of extending total day length of growing season, but not by temperature-driven acceleration of soil carbon decomposition, which argues against the possibility of a strong positive feedback between global warming and soil carbon loss. Different nitrogen loads can trigger distinct belowground carbon allocation mechanisms, which are responsible for different responses of soil respiration to nitrogen addition that have been observed. These results provide new insights into belowground carbon allocation, partitioning of soil

  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.

  14. 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.

  15. A systematic review of the psychometric properties of the Sexual Relationship Power Scale in HIV/AIDS research.

    PubMed

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

    2015-02-01

    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, which reported reliability or construct validity estimates of the scales. Description of the psychometric properties of the SRPS and subscales is 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 (1) the application and use of the SRPS and subscales, (2) reporting of psychometric properties of the scales in the literature, and (3) areas for future research.

  16. 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

  17. 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.

  18. Understanding relationships among abundance, extirpation,and climate at ecoregional scales

    USGS Publications Warehouse

    Beever, Erik A.; Solomon Dubrowski,; ,; ,; J. Long,; ,; A. Mysnberge,; Piekielek, N. B.

    2014-01-01

    Recent research on mountain-dwelling species has illustrated changes in species’ distributional patterns in response to climate change. Abundance of a species will likely provide an earlier warning indicator of change than will occupancy, yet relationships between abundance and climatic factors have received less attention. We tested whether predictors of counts of American pikas (Ochotona princeps) during surveys from the Great Basin region in 1994–1999 and 2003–2008 differed between the two periods. Additionally, we tested whether various modeled aspects of ecohydrology better predicted relative density than did average annual precipitation, and whether risk of site-wide extirpation predicted subsequent population counts of pikas. We observed several patterns of change in pika abundance at range edges that likely constitute early warnings of distributional shifts. Predictors of pika abundance differed strongly between the survey periods, as did pika extirpation patterns previously reported from this region. Additionally, maximum snowpack and growing-season precipitation resulted in better-supported models than those using average annual precipitation, and constituted two of the top three predictors of pika density in the 2000s surveys (affecting pikas perhaps via vegetation). Unexpectedly, we found that extirpation risk positively predicted subsequent population size. Our results emphasize the need to clarify mechanisms underlying biotic responses to recent climate change at organism-relevant scales, to inform management and conservation strategies for species of concern.

  19. An optimum city size? The scaling relationship for urban population and fine particulate (PM(2.5)) concentration.

    PubMed

    Han, Lijian; Zhou, Weiqi; Pickett, Steward T A; Li, Weifeng; Li, Li

    2016-01-01

    We utilize the distribution of PM2.5 concentration and population in large cities at the global scale to illustrate the relationship between urbanization and urban air quality. We found: 1) The relationship varies greatly among continents and countries. Large cities in North America, Europe, and Latin America have better air quality than those in other continents, while those in China and India have the worst air quality. 2) The relationships between urban population size and PM2.5 concentration in large cities of different continents or countries were different. PM2.5 concentration in large cities in North America, Europe, and Latin America showed little fluctuation or a small increasing trend, but those in Africa and India represent a "U" type relationship and in China represent an inverse "U" type relationship. 3) The potential contribution of population to PM2.5 concentration was higher in the large cities in China and India, but lower in other large cities.

  20. Measuring thought content valence after a breakup: Development of the Positive and Negative Ex-Relationship Thoughts (PANERT) scale.

    PubMed

    Brenner, Rachel E; Vogel, David L

    2015-07-01

    The end of a romantic relationship is a common and serious presenting concern among clients at university counseling centers. Researchers have highlighted the need to understand the nature of thoughts about an ex-relationship, because they may lead to unique clinical interventions. One aspect of thought that may be clinically relevant is content valence, or the positive or negative emotions associated with the content of the thought. Unfortunately, content valence has not been addressed in the romantic relationship dissolution literature. To address this omission, we developed the 12-item Positive and Negative Ex-Relationship Thoughts (PANERT) scale across 4 samples. In Sample 1 (n = 475), exploratory factor analyses demonstrated a multidimensional scale with 2 factors: positive content valence and negative content valence. Sample 2 (n = 509) and Sample 3 (n = 291) confirmed the factor structure in college and community samples. Internal consistencies ranged from .88-.94 for positive content valence and from .87-.94 for negative content valence. In Sample 4 (n = 133), construct validity was supported, with the PANERT factors uniquely predicting breakup distress, relationship preoccupation, depression, loss of self-concept, rediscovery of self-concept, negative emotional adjustment, and positive emotional adjustment. Further, the direction of these relationships suggest that positive thought content valence may be consistently maladaptive to recovery from an ex-relationship, and negative thought content valence may have maladaptive and adaptive features. Implications for future research and practice are discussed.

  1. 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.

  2. 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

  3. Effect of biological maturation on maximal oxygen uptake and ventilatory thresholds in soccer players: an allometric approach.

    PubMed

    Cunha, Giovani; Lorenzi, Thiago; Sapata, Katiuce; Lopes, Andre Luiz; Gaya, Adroaldo Cezar; Oliveira, Álvaro

    2011-07-01

    In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O(2max)) and ventilatory thresholds (VT(1) and VT(2)) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O(2) corresponding to VT(1) and VT(2) were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O(2) (ml · min(-1)) was different between groups for VT(1), VT(2), and [Vdot]O(2max). Ratio standards (ml · kg(-1) · min(-1)) were not significantly different between groups for VT(1), VT(2), and [Vdot]O(2max). Theoretical exponents (ml · kg(-0.67) · min(-1) and ml · kg(-0.75) · min(-1)) were not properly adjusted for the body mass effects on VT(1), VT(2), and [Vdot]O(2max). When the data were correctly adjusted using experimentally observed exponents, VT(1) (ml · kg(-0.94) · min(-1)) and VT(2) (ml · kg(-0.95) · min(-1)) were not different between groups. The experimentally observed exponent for [Vdot]O(2max) (ml · kg(-0.90) · min(-1)) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT(1), VT(2) or [Vdot]O(2max) when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.

  4. 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

  5. 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…

  6. 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…

  7. Relationships between the Underlying Constructs of the Beck Depression Inventory and the Center for Epidemiological Studies Depression Scale.

    ERIC Educational Resources Information Center

    Skorikov, Vladimir B.; Vandervoort, Debra J.

    2003-01-01

    Examined the relationships between the constructs of depression as measured by the Center for Epidemiological Studies Depression Scale (CES-D) and the revised Beck Depression Inventory (BDI; Beck and others, 1979) in 261 college students. Findings suggest the BDI and CES-D measure different aspects of depression and should not be used…

  8. 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…

  9. 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…

  10. 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…

  11. 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 assess…

  12. Relationship between pumping-test and slug-test parameters: Scale effect or artifact?

    USGS Publications Warehouse

    Butler, J.J.; Healey, J.M.

    1998-01-01

    In most field investigations, information about hydraulic conductivity (K) is obtained through pumping or slug tests. A considerable body of data has been amassed that indicates that the K estimate from a pumping test is, on average, considerably larger than the estimate obtained from a series of slug tests in the same formation. Although these data could be interpreted as indicating a natural underlying scale dependence in K, an alternate explanation is that the slug-test K is artificially low as a result of incomplete well development and, to a much lesser extent, failure to account for vertical anisotropy. Incomplete well development will often result in only the most permeable zones being cleared of drilling debris, with much of the screened interval remaining undeveloped. More cursory development can leave a low-K skin along the entire screened interval. Failure to recognize such conditions can result in a K estimate from a slug test that is much lower than the average K of the formation in the vicinity of the well. By contrast, neither a skin nor vertical anisotropy will have a significant impact on K estimates from pumping tests when semi-log analyses and/or observation wells are used. However, a reasonable estimate of aquifer thickness is required to convert the transmissivity calculated from a pumping test Into an average K for the aquifer. Prior to invoking a natural scale dependence to explain the results of different types of hydraulic tests, head data should be closely examined and serious consideration given to alternate explanations.Pumping and slug tests are the primary means to obtain in situ estimates of the transmissive properties of a formation. Since the duration of most pumping tests is on the order of hours to days, the formation volume that is affected by the average pumping test is considerably larger than that affected by a slug test. These tests can yield different parameter estimates when performed at the same well. In this regard, the

  13. [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.

  14. 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

  15. The relationship between large-scale and convective states in the tropics - Towards an improved representation of convection in large-scale models

    SciTech Connect

    Jakob, Christian

    2015-02-26

    This report summarises an investigation into the relationship of tropical thunderstorms to the atmospheric conditions they are embedded in. The study is based on the use of radar observations at the Atmospheric Radiation Measurement site in Darwin run under the auspices of the DOE Atmospheric Systems Research program. Linking the larger scales of the atmosphere with the smaller scales of thunderstorms is crucial for the development of the representation of thunderstorms in weather and climate models, which is carried out by a process termed parametrisation. Through the analysis of radar and wind profiler observations the project made several fundamental discoveries about tropical storms and quantified the relationship of the occurrence and intensity of these storms to the large-scale atmosphere. We were able to show that the rainfall averaged over an area the size of a typical climate model grid-box is largely controlled by the number of storms in the area, and less so by the storm intensity. This allows us to completely rethink the way we represent such storms in climate models. We also found that storms occur in three distinct categories based on their depth and that the transition between these categories is strongly related to the larger scale dynamical features of the atmosphere more so than its thermodynamic state. Finally, we used our observational findings to test and refine a new approach to cumulus parametrisation which relies on the stochastic modelling of the area covered by different convective cloud types.

  16. Nonverbal cognitive development in children with cochlear implants: relationship between the Mullen Scales of Early Learning and later performance on the Leiter International Performance Scales-Revised.

    PubMed

    Caudle, Susan E; Katzenstein, Jennifer M; Oghalai, John S; Lin, Jerry; Caudle, Donald D

    2014-02-01

    Methodologically, longitudinal assessment of cognitive development in young children has proven difficult because few measures span infancy through school age. This matter is further complicated when the child presents with a sensory deficit such as hearing loss. Few measures are validated in this population, and children who are evaluated for cochlear implantation are often reevaluated annually. The authors sought to evaluate the predictive validity of subscales of the Mullen Scales of Early Learning (MSEL) on Leiter International Performance Scales-Revised (LIPS-R) Full-Scale IQ scores. To further elucidate the relationship of these two measures, comparisons were also made with the Vineland Adaptive Behavior Scale-Second Edition (VABS), which provides a measure of adaptive functioning across the life span. Participants included 35 children (14 female, 21 male) who were evaluated both as part of the precandidacy process for cochlear implantation using the MSEL and VABS and following implantation with the LIPS-R and VABS. Hierarchical linear regression revealed that the MSEL Visual Reception subdomain score significantly predicted 52% of the variance in LIPS-R Full-Scale IQ scores at follow-up, F(1, 34) = 35.80, p < .0001, R (2) = .52, β = .72. This result suggests that the Visual Reception subscale offers predictive validity of later LIPS-R Full-Scale IQ scores. The VABS was also significantly correlated with cognitive variables at each time point.

  17. Scaling and functional morphology in strigiform hind limbs

    PubMed Central

    Madan, Meena A.; Rayfield, Emily J.; Bright, Jen A.

    2017-01-01

    Strigiformes are an order of raptorial birds consisting exclusively of owls: the Tytonidae (barn owls) and the Strigidae (true owls), united by a suite of adaptations aiding a keen predatory lifestyle, including robust hind limb elements modified for grip strength. To assess variation in hind limb morphology, we analysed how the dimensions of the major hind limb elements in subfossil and modern species scaled with body mass. Comparing hind limb element length, midshaft width, and robusticity index (RI: ratio of midshaft width to maximum length) to body mass revealed that femoral and tibiotarsal width scale with isometry, whilst length scales with negative allometry, and close to elastic similarity in the tibiotarsus. In contrast, tarsometatarsus width shows strong positive allometry with body mass, whilst length shows strong negative allometry. Furthermore, the tarsometatarsi RI scales allometrically to mass0.028, whilst a weak relationship exists in femora (mass0.004) and tibiotarsi (mass0.004). Our results suggest that tarsometatarsi play a more substantial functional role than tibiotarsi and femora. Given the scaling relationship between tarsometatarsal width and robusticity to body mass, it may be possible to infer the body mass of prehistoric owls by analysing tarsometatarsi, an element that is frequently preserved in the fossil record of owls. PMID:28327549

  18. Probability of ventricular fibrillation: allometric model based on the ST deviation

    PubMed Central

    2011-01-01

    Background Allometry, in general biology, measures the relative growth of a part in relation to the whole living organism. Using reported clinical data, we apply this concept for evaluating the probability of ventricular fibrillation based on the electrocardiographic ST-segment deviation values. Methods Data collected by previous reports were used to fit an allometric model in order to estimate ventricular fibrillation probability. Patients presenting either with death, myocardial infarction or unstable angina were included to calculate such probability as, VFp = δ + β (ST), for three different ST deviations. The coefficients δ and β were obtained as the best fit to the clinical data extended over observational periods of 1, 6, 12 and 48 months from occurrence of the first reported chest pain accompanied by ST deviation. Results By application of the above equation in log-log representation, the fitting procedure produced the following overall coefficients: Average β = 0.46, with a maximum = 0.62 and a minimum = 0.42; Average δ = 1.28, with a maximum = 1.79 and a minimum = 0.92. For a 2 mm ST-deviation, the full range of predicted ventricular fibrillation probability extended from about 13% at 1 month up to 86% at 4 years after the original cardiac event. Conclusions These results, at least preliminarily, appear acceptable and still call for full clinical test. The model seems promising, especially if other parameters were taken into account, such as blood cardiac enzyme concentrations, ischemic or infarcted epicardial areas or ejection fraction. It is concluded, considering these results and a few references found in the literature, that the allometric model shows good predictive practical value to aid medical decisions. PMID:21226961

  19. 10 km running performance predicted by a multiple linear regression model with allometrically adjusted variables

    PubMed Central

    Abad, Cesar C. C.; Barros, Ronaldo V.; Bertuzzi, Romulo; Gagliardi, João F. L.; Lima-Silva, Adriano E.; Lambert, Mike I.

    2016-01-01

    Abstract The aim of this study was to verify the power of VO2max, peak treadmill running velocity (PTV), and running economy (RE), unadjusted or allometrically adjusted, in predicting 10 km running performance. Eighteen male endurance runners performed: 1) an incremental test to exhaustion to determine VO2max and PTV; 2) a constant submaximal run at 12 km·h−1 on an outdoor track for RE determination; and 3) a 10 km running race. Unadjusted (VO2max, PTV and RE) and adjusted variables (VO2max0.72, PTV0.72 and RE0.60) were investigated through independent multiple regression models to predict 10 km running race time. There were no significant correlations between 10 km running time and either the adjusted or unadjusted VO2max. Significant correlations (p < 0.01) were found between 10 km running time and adjusted and unadjusted RE and PTV, providing models with effect size > 0.84 and power > 0.88. The allometrically adjusted predictive model was composed of PTV0.72 and RE0.60 and explained 83% of the variance in 10 km running time with a standard error of the estimate (SEE) of 1.5 min. The unadjusted model composed of a single PVT accounted for 72% of the variance in 10 km running time (SEE of 1.9 min). Both regression models provided powerful estimates of 10 km running time; however, the unadjusted PTV may provide an uncomplicated estimation. PMID:28149382

  20. 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.

  1. On the Validity of the Psychosocial Maturity Scales: Relationship to Teacher Ratings. Report No. 171.

    ERIC Educational Resources Information Center

    Josselson, Ruthellen; And Others

    This study attempts to provide evidence for the criterion validity of the Psychosocial Maturity (PSM) scales. Students' scores on the nine PSM scales were related to teachers' ratings of student PSM-related behavior. All scales except Trust significantly differentiated students rated high on PSM-related traits from students not rated high. Only…

  2. 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

  3. 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

  4. A general model for metabolic scaling in self-similar asymmetric networks

    PubMed Central

    Savage, Van M.; Enquist, Brian J.

    2017-01-01

    How a particular attribute of an organism changes or scales with its body size is known as an allometry. Biological allometries, such as metabolic scaling, have been hypothesized to result from selection to maximize how vascular networks fill space yet minimize internal transport distances and resistances. The West, Brown, Enquist (WBE) model argues that these two principles (space-filling and energy minimization) are (i) general principles underlying the evolution of the diversity of biological networks across plants and animals and (ii) can be used to predict how the resulting geometry of biological networks then governs their allometric scaling. Perhaps the most central biological allometry is how metabolic rate scales with body size. A core assumption of the WBE model is that networks are symmetric with respect to their geometric properties. That is, any two given branches within the same generation in the network are assumed to have identical lengths and radii. However, biological networks are rarely if ever symmetric. An open question is: Does incorporating asymmetric branching change or influence the predictions of the WBE model? We derive a general network model that relaxes the symmetric assumption and define two classes of asymmetrically bifurcating networks. We show that asymmetric branching can be incorporated into the WBE model. This asymmetric version of the WBE model results in several theoretical predictions for the structure, physiology, and metabolism of organisms, specifically in the case for the cardiovascular system. We show how network asymmetry can now be incorporated in the many allometric scaling relationships via total network volume. Most importantly, we show that the 3/4 metabolic scaling exponent from Kleiber’s Law can still be attained within many asymmetric networks. PMID:28319153

  5. A general model for metabolic scaling in self-similar asymmetric networks.

    PubMed

    Brummer, Alexander Byers; Savage, Van M; Enquist, Brian J

    2017-03-01

    How a particular attribute of an organism changes or scales with its body size is known as an allometry. Biological allometries, such as metabolic scaling, have been hypothesized to result from selection to maximize how vascular networks fill space yet minimize internal transport distances and resistances. The West, Brown, Enquist (WBE) model argues that these two principles (space-filling and energy minimization) are (i) general principles underlying the evolution of the diversity of biological networks across plants and animals and (ii) can be used to predict how the resulting geometry of biological networks then governs their allometric scaling. Perhaps the most central biological allometry is how metabolic rate scales with body size. A core assumption of the WBE model is that networks are symmetric with respect to their geometric properties. That is, any two given branches within the same generation in the network are assumed to have identical lengths and radii. However, biological networks are rarely if ever symmetric. An open question is: Does incorporating asymmetric branching change or influence the predictions of the WBE model? We derive a general network model that relaxes the symmetric assumption and define two classes of asymmetrically bifurcating networks. We show that asymmetric branching can be incorporated into the WBE model. This asymmetric version of the WBE model results in several theoretical predictions for the structure, physiology, and metabolism of organisms, specifically in the case for the cardiovascular system. We show how network asymmetry can now be incorporated in the many allometric scaling relationships via total network volume. Most importantly, we show that the 3/4 metabolic scaling exponent from Kleiber's Law can still be attained within many asymmetric networks.

  6. 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

  7. Source scaling relationships of small earthquakes estimated from the inversion method using stopping phases

    NASA Astrophysics Data System (ADS)

    Imanishi, K.; Takeo, M.; Ito, H.; Ellsworth, W.; Matsuzawa, T.; Kuwahara, Y.; Iio, Y.; Horiuchi, S.; Ohmi, S.

    2002-12-01

    We estimate source parameters of small earthquakes from stopping phases and investigate the scaling relationships between source parameters. The method we employed [Imanishi and Takeo, 2002] assumes an elliptical fault model proposed by Savage [1966]. In this model, two high-frequency stopping phases, Hilbert transformations of each other, are radiated and the difference in arrival times between the two stopping phases is dependent on the average value of rupture velocity, the source dimension, the aspect ratio of elliptical fault, the direction of rupture propagation and the orientation of the fault plane. These parameters can be estimated by a nonlinear least squares inversion method. Earthquakes studied occurred between May and August 1999 at the western Nagano prefecture, Japan, which is characterized by high levels of shallow earthquakes. The data consist of seismograms recorded by an 800 m deep borehole and a 46 surface seismic array whose spacing is a few km. In particular, the 800 m borehole data provide a wide frequency bandwidth and greatly reduce ground noise and coda wave amplitude compared to surface recordings. High-frequency stopping phases are readily detected on accelerograms recorded in the borehole. After correcting both borehole and surface data for attenuation, we also measure the rise time, which is defined as the time lag from the arrival time of the direct wave to the first slope change in the displacement pulse. Using these durations, we estimate source parameters of 25 earthquakes ranging in size from M1.2 to M2.6. The rupture aspect ratio is estimated to be about 0.8 on an average. This suggests that the assumption of a circular crack model is valid as a first order approximation for earthquakes analyzed in this study. Static stress drops range from approximately 0.1 to 5 MPa and do not vary with seismic moment. It seems that the breakdown seen in the previous studies by other authors using surface data is simply an artifact of

  8. 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 ...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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…

  15. 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…

  16. Brief report: Intimacy, passion, and commitment in romantic relationships--validation of a 'triangular love scale' for adolescents.

    PubMed

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

    2007-06-01

    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, and commitment were all positively correlated with relationship satisfaction and duration. Evidence was also found for divergent validity, as adolescents' perceptions of the main (dis)advantages of being involved in romantic relationships showed a specific pattern of associations with intimacy, passion, and commitment. Finally, CFA analyses in LISREL showed that a model in which all separate questionnaire items were specified to load on three underlying, correlated factors (intimacy, passion, commitment) fit the data adequately. Overall, this measure seems appropriate for use with adolescents.

  17. Scaling of olfactory antennae of the terrestrial hermit crabs Coenobita rugosus and Coenobita perlatus during ontogeny

    PubMed Central

    Bantay, Roxanne M.; Nguyen, Quang V.

    2014-01-01

    Although many lineages of terrestrial crustaceans have poor olfactory capabilities, crabs in the family Coenobitidae, including the terrestrial hermit crabs in the genus Coenobita, are able to locate food and water using olfactory antennae (antennules) to capture odors from the surrounding air. Terrestrial hermit crabs begin their lives as small marine larvae and must find a suitable place to undergo metamorphosis into a juvenile form, which initiates their transition to land. Juveniles increase in size by more than an order of magnitude to reach adult size. Since odor capture is a process heavily dependent on the size and speed of the antennules and physical properties of the fluid, both the transition from water to air and the large increase in size during ontogeny could impact odor capture. In this study, we examine two species of terrestrial hermit crabs, Coenobita perlatus H. Milne-Edwards and Coenobita rugosus H. Milne-Edwards, to determine how the antennule morphometrics and kinematics of flicking change in comparison to body size during ontogeny, and how this scaling relationship could impact odor capture by using a simple model of mass transport in flow. Many features of the antennules, including the chemosensory sensilla, scaled allometrically with carapace width and increased slower than expected by isometry, resulting in relatively larger antennules on juvenile animals. Flicking speed scaled as expected with isometry. Our mass-transport model showed that allometric scaling of antennule morphometrics and kinematics leads to thinner boundary layers of attached fluid around the antennule during flicking and higher odorant capture rates as compared to antennules which scaled isometrically. There were no significant differences in morphometric or kinematic measurements between the two species. PMID:25177536

  18. The Relationship between Spatial and Temporal Magnitude Estimation of Scientific Concepts at Extreme Scales

    NASA Astrophysics Data System (ADS)

    Price, Aaron; Lee, H.

    2010-01-01

    Many astronomical objects, processes, and events exist and occur at extreme scales of spatial and temporal magnitudes. Our research draws upon the psychological literature, replete with evidence of linguistic and metaphorical links between the spatial and temporal domains, to compare how students estimate spatial and temporal magnitudes associated with objects and processes typically taught in science class.. We administered spatial and temporal scale estimation tests, with many astronomical items, to 417 students enrolled in 12 undergraduate science courses. Results show that while the temporal test was more difficult, students’ overall performance patterns between the two tests were mostly similar. However, asymmetrical correlations between the two tests indicate that students think of the extreme ranges of spatial and temporal scales in different ways, which is likely influenced by their classroom experience. When making incorrect estimations, students tended to underestimate the difference between the everyday scale and the extreme scales on both tests. This suggests the use of a common logarithmic mental number line for both spatial and temporal magnitude estimation. However, there are differences between the two tests in the errors student make in the everyday range. Among the implications discussed is the use of spatio-temporal reference frames, instead of smooth bootstrapping, to help students maneuver between scales of magnitude and the use of logarithmic transformations between reference frames. Implications for astronomy range from learning about spectra to large scale galaxy structure.

  19. Inter-relationships between corrosion and mineral-scale deposition in aqueous systems.

    PubMed

    Hodgkiess, T

    2004-01-01

    The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed.

  20. 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

  1. 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.

  2. 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.

  3. Continental-scale relationship between bankfull width and drainage area for single-thread alluvial channels

    NASA Astrophysics Data System (ADS)

    Wilkerson, Gregory V.; Kandel, Dinesh R.; Perg, Lesley A.; Dietrich, William E.; Wilcock, Peter R.; Whiles, Matt R.

    2014-02-01

    We explore the bankfull width (Wbf) versus drainage area (Ada) relationship across a range of climatic and geologic environments and ask (1) is the relationship between ln(Wbf) and ln(Ada) best described by a linear function and (2) can a reliable relationship be developed for predicting Wbf with Ada as the only independent variable. The principal data set for this study was compiled from regional curve studies and other reports that represent 1018 sites (1 m ≤ Wbf ≤ 110 m and 0.50 km2 ≤ Ada ≤ 22,000 km2) in the continental United States. Two additional data sets were used for validation. After dividing the data into small, medium, and large-size basins which, respectfully, correspond to Ada < 4.95 km2, 4.95 km2 ≤ Ada < 337 km2, and Ada ≥ 337 km2, regression lines from each data set were compared using one-way analysis of covariance (ANCOVA). A second ANCOVA was performed to determine if mean annual precipitation (P) is an extraneous factor in the Wbf versus Ada relationship. The ANCOVA results reveal that using Ada alone does not yield a reliable Wbf versus Ada relationship that is applicable across a wide range of environments and that P is a significant extraneous factor in the relationship. Considering data for very small basins (Ada ≤ 0.49 km2) and very large basins (Ada ≥ 1.0 × 105 km2) we conclude that a two-segment linear model is the most probable form of the ln(Wbf) versus ln(Ada) relationship. This study provides useful information for building complex multivariate models for predicting Wbf.

  4. 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)

  5. Long-term and large-scale perspectives on the relationship between biodiversity and ecosystem functioning

    USGS Publications Warehouse

    Symstad, A.J.; Chapin, F. S.; Wall, D.H.; Gross, K.L.; Huenneke, L.F.; Mittelbach, G.G.; Peters, Debra 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.

  6. 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.

  7. 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.

  8. 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.

  9. Bird and mammal species composition in distinct geographic regions and their relationships with environmental factors across multiple spatial scales.

    PubMed

    Kent, Rafi; Bar-Massada, Avi; Carmel, Yohay

    2014-05-01

    Global patters of species distributions and their underlying mechanisms are a major question in ecology, and the need for multi-scale analyses has been recognized. Previous studies recognized climate, topography, habitat heterogeneity and disturbance as important variables affecting such patterns. Here we report on analyses of species composition - environment relationships among different taxonomic groups in two continents, and the components of such relationships, in the contiguous USA and Australia. We used partial Canonical Correspondence Analysis of occurrence records of mammals and breeding birds from the Global Biodiversity Information Facility, to quantify relationships between species composition and environmental variables in remote geographic regions at multiple spatial scales, with extents ranging from 10(5) to 10(7) km(2) and sampling grids from 10 to 10,000 km(2). We evaluated the concept that two elements contribute to the impact of environmental variables on composition: the strength of species' affinity to an environmental variable, and the amount of variance in the variable. To disentangle these two elements, we analyzed correlations between resulting trends and the amount of variance contained in different environmental variables to isolate the mechanisms behind the observed relationships. We found that climate and land use-land cover are responsible for most explained variance in species composition, regardless of scale, taxonomic group and geographic region. However, the amount of variance in species composition attributed to land use / land cover (LULC) was closely related to the amount of intrinsic variability in LULC in the USA, but not in Australia, while the effect of climate on species composition was negatively correlated to the variability found in the climatic variables. The low variance in climate, compared to LULC, suggests that species in both taxonomic groups have strong affinity to climate, thus it has a strong effect on species

  10. General relationship of global topology, local dynamics, and directionality in large-scale brain networks.

    PubMed

    Moon, Joon-Young; Lee, UnCheol; Blain-Moraes, Stefanie; Mashour, George A

    2015-04-01

    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.

  11. Using plastid genome-scale data to resolve enigmatic relationships among basal angiosperms

    PubMed Central

    Moore, Michael J.; Bell, Charles D.; Soltis, Pamela S.; Soltis, Douglas E.

    2007-01-01

    Although great progress has been made in clarifying deep-level angiosperm relationships, several early nodes in the angiosperm branch of the Tree of Life have proved difficult to resolve. Perhaps the last great question remaining in basal angiosperm phylogeny involves the branching order among the five major clades of mesangiosperms (Ceratophyllum, Chloranthaceae, eudicots, magnoliids, and monocots). Previous analyses have found no consistent support for relationships among these clades. In an effort to resolve these relationships, we performed phylogenetic analyses of 61 plastid genes (≈42,000 bp) for 45 taxa, including members of all major basal angiosperm lineages. We also report the complete plastid genome sequence of Ceratophyllum demersum. Parsimony analyses of combined and partitioned data sets varied in the placement of several taxa, particularly Ceratophyllum, whereas maximum-likelihood (ML) trees were more topologically stable. Total evidence ML analyses recovered a clade of Chloranthaceae + magnoliids as sister to a well supported clade of monocots + (Ceratophyllum + eudicots). ML bootstrap and Bayesian support values for these relationships were generally high, although approximately unbiased topology tests could not reject several alternative topologies. The extremely short branches separating these five lineages imply a rapid diversification estimated to have occurred between 143.8 ± 4.8 and 140.3 ± 4.8 Mya. PMID:18048334

  12. 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

  13. Invasive plants have scale-dependent effects on diversity by altering species-area relationships.

    PubMed

    Powell, Kristin I; Chase, Jonathan M; Knight, Tiffany M

    2013-01-18

    Although invasive plant species often reduce diversity, they rarely cause plant extinctions. We surveyed paired invaded and uninvaded plant communities from three biomes. We reconcile the discrepancy in diversity loss from invaders by showing that invaded communities have lower local richness but steeper species accumulation with area than that of uninvaded communities, leading to proportionately fewer species loss at broader spatial scales. We show that invaders drive scale-dependent biodiversity loss through strong neutral sampling effects on the number of individuals in a community. We also show that nonneutral species extirpations are due to a proportionately larger effect of invaders on common species, suggesting that rare species are buffered against extinction. Our study provides a synthetic perspective on the threat of invasions to biodiversity loss across spatial scales.

  14. 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.

  15. 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

  16. The small-world organization of large-scale brain systems and relationships with subcortical structures.

    PubMed

    Koziol, Leonard F; Barker, Lauren A; Joyce, Arthur W; Hrin, Skip

    2014-01-01

    Brain structure and function is characterized by large-scale brain systems. However, each system has its own "small-world" organization, with sub-regions, or "hubs," that have varying degrees of specialization for certain cognitive and behavioral processes. This article describes this small-world organization, and the concepts of functional specialization and functional integration are defined and explained through practical examples. We also describe the development of large-scale brain systems and this small-world organization as a sensitive, protracted process, vulnerable to a variety of influences that generate neurodevelopmental disorders.

  17. Scaling relationships in photoelectron-photoion coincidence studies: The aceton ion dissociation

    NASA Astrophysics Data System (ADS)

    Johnson, Kieth; Powis, I.; Danby, C. J.

    1981-12-01

    The distributions of internal energy released into translation in the fragmentation of energy-selected acetone ions (as determined by photoelectron-photoion coincidence studies) are shown to obey a scaling law, as do the calculated distributions derived from a statistical-dynamical phase space theory. A single function contains the dynamical history of the reaction system, at least at higher energies, in contrast to the predictions of the rigid rotor harmonic oscillator model. The scaling law provides an analysis of the bimodal form of the translational energy distributions which are found for the dissociation of the enol form of the acetone ion. This is shown to be consistent with the ergodic hypothesis.

  18. Scaling relationships for nonadiabatic energy relaxation times in warm dense matter: toward understanding the equation of state.

    PubMed

    Pradhan, Ekadashi; Magyar, Rudolph J; Akimov, Alexey V

    2016-11-30

    Understanding the dynamics of electron-ion energy transfer in warm dense (WD) matter is important to the measurement of equation of state (EOS) properties and for understanding the energy balance in dynamic simulations. In this work, we present a comprehensive investigation of nonadiabatic electron relaxation and thermal excitation dynamics in aluminum under high pressure and temperature. Using quantum-classical trajectory surface hopping approaches, we examine the role of nonadiabatic couplings and electronic decoherence in electron-nuclear energy transfer in WD aluminum. The computed timescales range from 400 fs to 4.0 ps and are consistent with existing experimental studies. We have derived general scaling relationships between macroscopic parameters of WD systems such as temperature or mass density and the timescales of energy redistribution between quantum and classical degrees of freedom. The scaling laws are supported by computational results. We show that electronic decoherence plays essential role and can change the functional dependencies qualitatively. The established scaling relationships can be of use in modelling of WD matter.

  19. A study of energy-size relationship and wear rate in a lab-scale high pressure grinding rolls unit

    NASA Astrophysics Data System (ADS)

    Rashidi Dashtbayaz, Samira

    This study is focused on two independent topics of energy-size relationship and wear-rate measurements on a lab-scale high pressure grinding rolls (HPGR). The first part of this study has been aimed to investigate the influence of the operating parameters and the feed characteristics on the particle-bed breakage using four different ore samples in a 200 mm x 100 mm lab-scale HPGR. Additionally, multistage grinding, scale-up from a lab-scale HPGR, and prediction of the particle size distributions have been studied in detail. The results obtained from energy-size relationship studies help with better understanding of the factors contributing to more energy-efficient grinding. It will be shown that the energy efficiency of the two configurations of locked-cycle and open multipass is completely dependent on the ore properties. A test procedure to produce the scale-up data is presented. The comparison of the scale-up factors between the data obtained on the University of Utah lab-scale HPGR and the industrial machine at the Newmont Boddington plant confirmed the applicability of lab-scale machines for trade-off studies. The population balance model for the simulation of product size distributions has shown to work well with the breakage function estimated through tests performed on the HPGR at high rotational speed. Selection function has been estimated by back calculation of population balance model with the help of the experimental data. This is considered to be a major step towards advancing current research on the simulation of particle size distribution by using the HPGR machine for determining the breakage function. Developing a technique/setup to measure the wear rate of the HPGR rolls' surface is the objective of the second topic of this dissertation. A mockup was initially designed to assess the application of the linear displacement sensors for measuring the rolls' weight loss. Upon the analysis of that technique and considering the corresponding sources of

  20. 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, ...

  1. 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…

  2. 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…

  3. 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

  4. Reliability and Validity of a Self-Concept Scale for Researchers in Family Relationships

    ERIC Educational Resources Information Center

    Rathus, Spencer A.; Siegel, Larry J.

    1976-01-01

    Self-concept questionnaire was shown to have high test-retest reliability, but only fair to moderate split-half (odd-even) reliability. Validity was adequate. The scale will serve as a heuristic device for family counselors who require a rapid assessment of a child's self-esteem. (Author)

  5. The Development of a Sexual Harassment Proclivity Scale: Construct Validation and Relationship to Communication Competence.

    ERIC Educational Resources Information Center

    Bingham, Shereen G.; Burleson, Brant R.

    1996-01-01

    Develops and assesses the validity of a self-report measure of sexual harassment proclivities in men. Demonstrates the validity of the scale by its moderate correlations with attitude measures relevant to sexual harassment, its nonsignificant correlation with the need to provide socially desirable responses, and by showing that potential victims…

  6. Structure–property relationships in atomic-scale junctions: Histograms and beyond

    SciTech Connect

    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, the 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.

  7. 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.

  8. 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

  9. 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.

  10. Continental-Scale View of Bankfull Width Versus Drainage Area Relationship

    NASA Astrophysics Data System (ADS)

    Wilkerson, G. V.

    2012-12-01

    While recognizing that there are multiple variables that influence bankfull channel width (Wbf), this study explores the relationship between Wbf and drainage area (Ada) across a range of geologic, terrestrial, climatic, and botanical environments. The study aims to develop a foundational model that will facilitate developing a comprehensive multivariate model for predicting channel width. Data for this study was compiled from independent regional curve studies (i.e., studies in which Wbf vs. Ada relationships are developed). The data represent 1,018 sites that span 12 states in the continental U.S. The channels are alluvial and are such that 1 m ≤ Wbf ≤ 110 m and 0.50 km2 ≤ Ada ≤ 22,000 km2. For developing regional curves, the Wbf vs. Ada relationship is generally assumed to be log-linear. Also, past studies have indicated that the Wbf vs. Ada relationship differs for small basins (i.e., 10 to 100 km2) and large basins due to the effects of vegetation. Linear and nonlinear (i.e., sigmoidal) models were considered for this study. The best model relates ln(Wbf ) and ln(Ada) using a three-piece linear model (Figure 1). The value of dWbf /dAda is significantly greater (p < 0.001) for mid-size basins (5 km2 ≤ Ada ≤ 350 km2) than either small or large basins. The noted change in dWbf /dAda is likely in response to vegetation. Also, the change in dWbf /dAda is so abrupt that the three-piece linear model, fits the data better than any of the sigmoidal functions explored in this study. For every model evaluated in this study, the residuals were bi-modal (Figure 2). For the residuals to begin converging on a normal distribution, at least one other factor (probably precipitation) needs to be included in the model.

  11. [Development of the Feelings toward Nature Scale and relationship between feelings toward nature and proximity to nature].

    PubMed

    Shibata, Seiji

    2016-04-01

    In the field of environmental psychology, there is rapidly growing interest in the concept of connectivity with nature, describing an individual's sense of being connected with nature. The author developed a new scale for assessing feelings toward nature, including connectedness. Confirmatory factor analysis indicated a five-factor model consisting of restorativeness, oneness, mystery, care, and aversion. Then, the relationships among availability of nature in respondents' neighborhood, age, and each subscale score of the Feelings toward Nature Scale, were analyzed using structural equation modeling. The availability of nature in neighborhoods was assessed using a geographic information system and respondents' subjective evaluations. Results indicate that overall connectedness to nature is weaker as availability of nature decreases, as assessed by subjective evaluation. Results also suggest that aversion toward nature in younger people is relatively stronger than in older generations.

  12. Source scaling relationships of microearthquakes at Parkfield, CA, determined using the SAFOD Pilot Hole Seismic Array

    NASA Astrophysics Data System (ADS)

    Imanishi, Kazutoshi; Ellsworth, William L.

    We estimate the source parameters of 34 microearthquakes at Parkfield, CA, ranging in size from M -0.2 to M 2.1, by analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We succeeded in obtaining stable spectral ratios by stacking the ratios calculated from the moving windows taken along the record following the direct waves. These spectral ratios were modeled to determine seismic moments and corner frequencies assuming an omega-squared model. Static stress drops and apparent stresses of microearthquakes at Parkfield display moment-independent scaling in agreement with scaling laws reported for moderate and large earthquakes. It is likely that the dynamics of microearthquakes at Parkfield is macroscopically similar to that of larger tectonic earthquakes.

  13. Cities, traffic, and CO2: A multidecadal assessment of trends, drivers, and scaling relationships

    DOE PAGES

    Gately, Conor K.; Hutyra, Lucy R.; Sue Wing, Ian

    2015-04-06

    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-roadmore » 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. Here, 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. Here, 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.« less

  14. 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.

  15. 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).

  16. New Insights about Enzyme Evolution from Large Scale Studies of Sequence and Structure Relationships*

    PubMed Central

    Brown, Shoshana D.; Babbitt, Patricia C.

    2014-01-01

    Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfamilies, each representing a large set of sequences that evolved from a common ancestor and that retain conserved features of their structures and active sites. Using several examples, we describe the different structural strategies nature has used to evolve new reaction and substrate specificities in each unique superfamily. The results provide insight about enzyme evolution that is not easily obtained from studies of one or only a few enzymes. PMID:25210038

  17. New insights about enzyme evolution from large scale studies of sequence and structure relationships.

    PubMed

    Brown, Shoshana D; Babbitt, Patricia C

    2014-10-31

    Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfamilies, each representing a large set of sequences that evolved from a common ancestor and that retain conserved features of their structures and active sites. Using several examples, we describe the different structural strategies nature has used to evolve new reaction and substrate specificities in each unique superfamily. The results provide insight about enzyme evolution that is not easily obtained from studies of one or only a few enzymes.

  18. 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.

  19. Quantifying Mountain Block Recharge by Means of Catchment-Scale Storage-Discharge Relationships

    NASA Astrophysics Data System (ADS)

    Ajami, H.; Troch, P. A.; Maddock, T.; Meixner, T.; Eastoe, C. J.

    2009-12-01

    Despite the hydrologic significance of mountainous catchments in providing freshwater resources, especially in semi-arid regions, little is known about key hydrological processes in these systems, such as mountain block recharge (MBR). We developed an empirical approach based on the storage sensitivity function introduced by Kirchner (2009) to develop storage-discharge relationships from stream flow analysis. We investigated sensitivity of MBR estimates to uncertainty in the derivation of the catchment storage-discharge relations. We implemented this technique in a semi-arid mountainous catchment in South-east Arizona, USA (the Marshall Gulch catchment in the Santa Catalina Mountains near Tucson) with two distinct rainy seasons, winter frontal storms and summer monsoon separated by prolonged dry periods. Developing storage-discharge relation based on baseflow data in the dry period allowed quantifying change in fractured bedrock storage caused by MBR. Contribution of fractured bedrock to stream flow was confirmed using stable isotope data. Our results show that 1) incorporating scalable time steps to correct for stream flow measurement errors improves the model fit; 2) the quantile method is more suitable for stream flow data binning; 3) the choice of the regression model is more critical when the stage-discharge function is used to predict changes in bedrock storage beyond the maximum observed flow in the catchment and 4) application of daily versus hourly flow did not affect the storage-discharge relationship. This methodology allowed quantifying MBR using stream flow recession analysis from within the mountain system.

  20. Structure–property relationships in atomic-scale junctions: Histograms and beyond

    DOE PAGES

    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

  1. [No relationship between blood type and personality: evidence from large-scale surveys in Japan and the US].

    PubMed

    Nawata, Kengo

    2014-06-01

    Despite the widespread popular belief in Japan about a relationship between personality and ABO blood type, this association has not been empirically substantiated. This study provides more robust evidence that there is no relationship between blood type and personality, through a secondary analysis of large-scale survey data. Recent data (after 2000) were collected using large-scale random sampling from over 10,000 people in total from both Japan and the US. Effect sizes were calculated. Japanese datasets from 2004 (N = 2,878-2,938), and 2,005 (N = 3,618-3,692) as well as one dataset from the US in 2004 (N = 3,037-3,092) were used. In all the datasets, 65 of 68 items yielded non-significant differences between blood groups. Effect sizes (eta2) were less than .003. This means that blood type explained less than 0.3% of the total variance in personality. These results show the non-relevance of blood type for personality.

  2. [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.

  3. 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

  4. Washout allometric reference method (WARM) for parametric analysis of [(11)C]PIB in human brains.

    PubMed

    Rodell, Anders; Aanerud, Joel; Braendgaard, Hans; Gjedde, Albert

    2013-01-01

    Rapid clearance and disappearance of a tracer from the circulation challenges the determination of the tracer's binding potentials in brain (BP ND) by positron emission tomography (PET). This is the case for the analysis of the binding of radiolabeled [(11)C]Pittsburgh Compound B ([(11)C]PIB) to amyloid-β (Aβ) plaques in brain of patients with Alzheimer's disease (AD). To resolve the issue of rapid clearance from the circulation, we here introduce the flow-independent Washout Allometric Reference Method (WARM) for the analysis of washout and binding of [(11)C]PIB in two groups of human subjects, healthy aged control subjects (HC), and patients suffering from AD, and we compare the results to the outcome of two conventional analysis methods. We also use the rapid initial clearance to obtain a surrogate measure of the rate of cerebral blood flow (CBF), as well as a method of identifying a suitable reference region directly from the [(11)C]PIB signal. The difference of average absolute CBF values between the AD and HC groups was highly significant (P < 0.003). The CBF measures were not significantly different between the groups when normalized to cerebellar gray matter flow. Thus, when flow differences confound conventional measures of [(11)C]PIB binding, the separate estimates of CBF and BP ND provide additional information about possible AD. The results demonstrate the importance of data-driven estimation of CBF and BP ND, as well as reference region detection from the [(11)C]PIB signal. We conclude that the WARM method yields stable measures of BP ND with relative ease, using only integration for noise reduction and no model regression. The method accounts for relative flow differences in the brain tissue and yields a calibrated measure of absolute CBF directly from the [(11)C]PIB signal. Compared to conventional methods, WARM optimizes the Aβ plaque load discrimination between patients with AD and healthy controls (P = 0.009).

  5. 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

  6. Relationship between family history of alcohol addiction, parents' education level, and smartphone problem use scale scores.

    PubMed

    Beison, Ashley; Rademacher, David J

    2017-03-01

    Background and aims Smartphones are ubiquitous. As smartphones increased in popularity, researchers realized that people were becoming dependent on their smartphones. The purpose here was to provide a better understanding of the factors related to problematic smartphone use (PSPU). Methods The participants were 100 undergraduates (25 males, 75 females) whose ages ranged from 18 to 23 (mean age = 20 years). The participants completed questionnaires to assess gender, ethnicity, year in college, father's education level, mother's education level, family income, age, family history of alcoholism, and PSPU. The Family Tree Questionnaire assessed family history of alcoholism. The Mobile Phone Problem Use Scale (MPPUS) and the Adapted Cell Phone Addiction Test (ACPAT) were used to determine the degree of PSPU. Whereas the MPPUS measures tolerance, escape from other problems, withdrawal, craving, and negative life consequences, the ACPAT measures preoccupation (salience), excessive use, neglecting work, anticipation, lack of control, and neglecting social life. Results Family history of alcoholism and father's education level together explained 26% of the variance in the MPPUS scores and 25% of the variance in the ACPAT scores. The inclusion of mother's education level, ethnicity, family income, age, year in college, and gender did not significantly increase the proportion of variance explained for either MPPUS or ACPAT scores. Discussion and conclusions Family history of alcoholism and father's education level are good predictors of PSPU. As 74%-75% of the variance in PSPU scale scores was not explained, future studies should aim to explain this variance.

  7. 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.

  8. Relationship between acid precipitation and three-dimensional transport associated with synoptic-scale cyclones

    SciTech Connect

    Haagenson, P.L.; Lazrus, A.L.; Kuo, Y.H.; Caldwell, G.A.

    1985-09-01

    Field data collected during APEX (Acid Precipitation Experiment) are used in combination with an isentropic trajectory model to analyze the relationship between acid precipitation and three-dimensional transport associated with cyclonic storms. Data are presented which indicate that high acidity in precipitation is often associated with slow transport speed and elevated SO2 concentrations in the dry air feeding into the precipitating regions. Conversely, low acidity is usually related to rapid transit, descending motion, and transport above the atmospheric boundary layer. The results also show that precipitation in the cold sector of a cyclone (in advance of the surface warm front) is often more acidic than that in other sectors of the storm. Four case studies are included to detail some of these meteorological effects. 19 references.

  9. Quantifying mountain block recharge by means of catchment-scale storage-discharge relationships

    NASA Astrophysics Data System (ADS)

    Ajami, Hoori; Troch, Peter A.; Maddock, Thomas, III; Meixner, Thomas; Eastoe, Chris

    2011-04-01

    Despite the importance of mountainous catchments for providing freshwater resources, especially in semi-arid regions, little is known about key hydrological processes such as mountain block recharge (MBR). Here we implement a data-based method informed by isotopic data to quantify MBR rates using recession flow analysis. We applied our hybrid method in a semi-arid sky island catchment in southern Arizona, United States. Sabino Creek is a 91 km2 catchment with its sources near the summit of the Santa Catalina Mountains northeast of Tucson. Southern Arizona's climate has two distinct wet seasons separated by prolonged dry periods. Winter frontal storms (November-March) provide about 50% of annual precipitation, and summers are dominated by monsoon convective storms from July to September. Isotope analyses of springs and surface water in the Sabino Creek catchment indicate that streamflow during dry periods is derived from groundwater storage in fractured bedrock. Storage-discharge relationships are derived from recession flow analysis to estimate changes in storage during wet periods. To provide reliable estimates, several corrections and improvements to classic base flow recession analysis are considered. These corrections and improvements include adaptive time stepping, data binning, and the choice of storage-discharge functions. Our analysis shows that (1) incorporating adaptive time steps to correct for streamflow measurement errors improves the coefficient of determination, (2) the quantile method is best for streamflow data binning, (3) the choice of the regression model is critical when the stage-discharge function is used to predict changes in bedrock storage beyond the maximum observed flow in the catchment, and (4) the use of daily or night-time hourly streamflow does not affect the form of the storage-discharge relationship but will impact MBR estimates because of differences in the observed range of streamflow in each series.

  10. Length scales of mantle heterogeneities and their relationship to ocean island basalt geochemistry

    NASA Astrophysics Data System (ADS)

    Kogiso, Tetsu; Hirschmann, Marc M.; Reiners, Peter W.

    2004-01-01

    The upper mantle is widely considered to be heterogeneous, possibly comprising a "marble-cake" mixture of heterogeneous domains in a relatively well-mixed matrix. The extent to which such domains are capable of producing and expelling melts with characteristic geochemical signatures upon partial melting, rather than equilibrating diffusively with surrounding peridotite, is a critical question for the origin of ocean island basalts (OIB) and mantle heterogeneity, but is poorly constrained. Central to this problem is the characteristic length scale of heterogeneous domains. If radiogenic osmium signatures in OIB are derived from discrete domains, then sub-linear correlations between Os isotopes and other geochemical indices, suggesting melt-melt mixing, may be used to constrain the length scales of these domains. These constraints arise because partial melts of geochemically distinct domains must segregate from their sources without significant equilibration with surrounding peridotite. Segregation of partial melts from such domains in upwelling mantle is promoted by compaction of the domain mineral matrix, and must occur faster than diffusive equilibration between the domain and its surroundings. Our calculations show that the diffusive equilibration time depends on the ratios of partition and diffusion coefficients of the partial melt and surrounding peridotite. Comparison of time scales between diffusion and melt segregation shows that segregation is more rapid than diffusive equilibration for Os, Sr, Pb, and Nd isotopes if the body widths are greater than tens of centimeter to several meters, depending on the aspect ratio of the bodies, on the melt fraction at which melt becomes interconnected in the bodies, and on the diffusivity in the solid. However, because Fe-Mg exchange occurs significantly more rapidly than equilibration of these isotopes under solid-state and partially molten conditions, it is possible that some domains can produce melts with Fe/Mg ratios

  11. Validating the Student-Teacher Relationship Scale: Testing Factor Structure and Measurement Invariance across Child Gender and Age in a Dutch Sample

    ERIC Educational Resources Information Center

    Koomen, Helma M. Y.; Verschueren, Karine; van Schooten, Erik; Jak, Suzanne; Pianta, Robert C.

    2012-01-01

    The Student-Teacher Relationship Scale (STRS) is widely used to examine teachers' relationships with young students in terms of closeness, conflict, and dependency. This study aimed to verify the dimensional structure of the STRS with confirmatory factor analysis, test its measurement invariance across child gender and age, improve its measurement…

  12. Patients' Perceived Involvement in Care Scale: relationship to attitudes about illness and medical care.

    PubMed

    Lerman, C E; Brody, D S; Caputo, G C; Smith, D G; Lazaro, C G; Wolfson, H G

    1990-01-01

    This report describes the development of the Perceived Involvement in Care Scale (PICS), a self-report questionnaire for patients, and its relation to primary care patients' attitudes regarding their illnesses and the management of them. The questionnaire was administered to three independent samples of adult primary care patients. Patients' satisfaction and their attitudes regarding their illnesses are evaluated after their medical visits. This instrument is designed to examine three relatively distinct factors: 1) doctor facilitation of patient involvement, 2) level of information exchange, and 3) patient participation in decision making. Of these factors, doctor facilitation and patient decision making were related significantly to patients' satisfaction with care. Doctor facilitation and information exchange related consistently to patients' perceptions of post-visit changes in their understanding, reassurance, perceived control over illness, and expectations for improvement in functioning. The role of physicians in enhancing patient involvement in care and the potential therapeutic benefits of physician facilitative behavior are addressed.

  13. 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.

  14. The Invalidating Childhood Environment Scale (ICES): psychometric properties and relationship to borderline personality symptomatology.

    PubMed

    Robertson, Christopher D; Kimbrel, Nathan A; Nelson-Gray, Rosemery O

    2013-06-01

    The objective of this study was to examine the psychometric properties of the Invalidating Childhood Environment Scale (ICES; Mountford, Corstorphine, Tomlinson, & Waller, 2004), a measure designed to retrospectively assess exposure to parental invalidation. The ICES was administered to a sample of female college students along with measures of parental bonding and borderline personality disorder (BPD) symptomatology. In contrast with previous findings, the ICES demonstrated excellent internal consistency within a nonclinical sample. It also correlated in the predicted directions with measures of parental bonding and BPD symptomatology. Taken together, these findings suggest that the ICES is a promising retrospective measure of parental invalidation. They also provide some support for the hypothesized link between parental invalidation and BPD symptomatology and suggest that additional research with clinical samples is needed.

  15. 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.

  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. 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

  18. 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.

  19. Relationships between scores of the Jefferson Scale of Physician Empathy (JSPE) and the Interpersonal Reactivity Index (IRI).

    PubMed

    Hojat, Mohammadreza; Mangione, Salvatore; Kane, Gregory C; Gonnella, Joseph S

    2005-11-01

    This study was designed to examine the relationships between scores of two measures of empathy. One was specifically developed for measuring empathy in patient care situations; the other was developed for the general population. It was hypothesized that the overlap between scores of the two measures would be greater for their constructs that are more relevant to patient care. Study participants were 93 first-year internal medicine residents at Thomas Jefferson University Hospital in Philadelphia. The Jefferson Scale of Physician Empathy (JSPE, specifically developed for administration to health professionals), and the Interpersonal Reactivity Index (IRI, developed for the general population) were administered. A statistically significant correlation of a moderate magnitude between the total scores of the JSPE and IRI (r = 0.45, p < 0.01) was found. The research hypothesis was confirmed by observing higher correlations between those scales of the IRI that were relevant to patient care (e.g. empathic concern, perspective taking) and related factors of the JSPE (compassionate care, perspective taking) than other scales of the IRI that seemed less relevant to patient care (e.g. personal distress and fantasy). These findings provide further support for the validity of the JSPE. It is concluded that physician empathy as measured by the JSPE and its underlying factors are distinct personal attributes that have a limited overlap with fantasy and no overlap with personal distress defined as dimensions of an empathy measure that was developed for the general population.

  20. Quantifying the fingerprint descriptor dependence of structure-activity relationship information on a large scale.

    PubMed

    Dimova, Dilyana; Stumpfe, Dagmar; Bajorath, Jürgen

    2013-09-23

    It is well-known that different molecular representations, e.g., graphs, numerical descriptors, fingerprints, or 3D models, change the numerical results of molecular similarity calculations. Because the assessment of structure-activity relationships (SARs) requires similarity and potency comparisons of active compounds, this representation dependence inevitably also affects SAR analysis. But to what extent? How exactly does SAR information change when alternative fingerprints are used as descriptors? What is the proportion of active compounds with substantial changes in SAR information induced by different fingerprints? To provide answers to these questions, we have quantified changes in SAR information across many different compound classes using six different fingerprints. SAR profiling was carried out on 128 target-based data sets comprising more than 60,000 compounds with high-confidence activity annotations. A numerical measure of SAR discontinuity was applied to assess SAR information on a per compound basis. For ~70% of all test compounds, changes in SAR characteristics were detected when different fingerprints were used as molecular representations. Moreover, the SAR phenotype of ~30% of the compounds changed, and distinct fingerprint-dependent local SAR environments were detected. The fingerprints we compared were found to generate SAR models that were essentially not comparable. Atom environment and pharmacophore fingerprints produced the largest differences in compound-associated SAR information. Taken together, the results of our systematic analysis reveal larger fingerprint-dependent changes in compound-associated SAR information than would have been anticipated.

  1. 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

  2. Scaling of VO2max and its relationship with insulin resistance in children.

    PubMed

    Ahn, Bumsoo; McMurray, Robert; Harrell, Joanne

    2013-02-01

    The relationship between insulin resistance (HOMA-IR), percent body fat, and aerobic fitness (VO2max per unit fat free mass; mL/kgFFM/min) was examined in 1,710 children. Percent body fat was estimated from sum of skinfolds, and VO2max was estimated from submaximal cycle ergometer tests. Overnight fasting blood samples were obtained. VO2max (mL/kgFFM/min) and percent body fat were correlated with HOMA-IR (r = -0.076, p < .002; r = .420, p < .001, respectively); as was VO2max in units of mL/kg/min (r = -0.264, p < .001). When VO2max in mL/kg/min was used, a progressive increase in HOMA-IR was found with decreasing fitness (p < .05). However, when mL/kgFFM/min was used, HOMA-IR scores remained similar between moderate-fit and low-fit group. The stronger association between aerobic fitness (mL/kg/min) and HOMA-IR is partially due to the significant association of fat mass to HOMA-IR. Therefore, our recommendation is to express aerobic fitness in units of mL/kgFFM/min to eliminate the confounding factor of adiposity and better understand the influence of muscle on insulin resistance.

  3. 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.

  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. Long-Period Oscillations of Hydraulic Fractures: Attenuation, Scaling Relationships, and Flow Stability

    NASA Astrophysics Data System (ADS)

    Lipovsky, B.; Dunham, E. M.

    2013-12-01

    Long-period seismicity due to the excitation of hydraulic fracture normal modes is thought to occur in many geological systems, including volcanoes, glaciers and ice sheets, and hydrocarbon reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluid within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis that accounts for quasi-dynamic elasticity of the fracture wall, as well as fluid drag, inertia, and compressibility. We consider symmetric perturbations and neglect the effects of stratification and gravity. In the long-wavelength or thin-fracture limit, dispersive guided waves known as crack waves propagate with phase velocity cw=√(G*|k|w/ρ), where G* = G/(1-υ) for shear modulus G and Poisson ratio υ, w is the crack half-width, k is the wavenumber, and ρ is the fluid density. Restoring forces from elastic wall deformation drive wave motions. In the opposite, short-wavelength limit, guided waves are simply sound waves within the fluid and little seismic excitation occurs due to minimal fluid-solid coupling. We focus on long-wavelength crack waves, which, in the form of standing wave modes in finite-length cracks, are thought to be a common mechanism for long-period seismicity. The dispersive nature of crack waves implies several basic scaling relations that might be useful when interpreting statistics of long-period events. Seismic observations may constrain a characteristic frequency f0 and seismic moment M0~GδwR2, where δw is the change in crack width and R is the crack dimension. Resonant modes of a fluid-filled crack have associated frequencies f~cw/R. Linear elasticity provides a link between pressure changes δp in the crack and the induced opening δw: δp~G δw/R. Combining these, and assuming that pressure changes have no variation with crack dimension, leads to the scaling law relating seismic moment and oscillation frequency, M0~(Gwδp/ρ)f0

  6. Hydraulic constraints in the functional scaling of trees.

    PubMed

    Mencuccini, Maurizio

    2002-06-01

    I conducted a literature survey to assess the available information on relationships between size--expressed in terms of diameter and dry biomass--and hydraulic efficiency of woody structures at different scales, from stem segments to whole trees. Three data sets were constructed: the first described the relationship between segment diameter and hydraulic conductivity (k(h); kg m s(-1) MPa(-1)) in four species; the second, for the same four species, described the intraspecific trajectories of change in total hydraulic conductance (G; kg s(-1) MPa(-1)) during ontogeny, i.e., from saplings to mature trees, thereby providing a comparison between allometric scaling laws at the scales of segments and whole trees; the third comprised pooled means for nine species that described the interspecific trajectory of change in G with tree size. The scaling coefficients obtained were compared with predictions made with an architectural fractal-like model incorporating tissue-specific hydraulic architecture parameters (West et al. 1999). When data on segment k(h) were examined, the fractal-like model closely predicted the scaling of k(h) with segment diameter in four species. However, the model failed to predict accurately in all species the intraspecific scaling at the branch and whole-tree levels, and consistently overestimated the scaling coefficients. The results suggest that ontogenetic changes in tree size during the life cycle of one tree may result in tradeoffs between optimal hydraulic supply to the existing leaf area and maintenance costs of the supporting xylem tissue. The model of West et al. (1999) may be useful for understanding broad interspecific patterns, but not for understanding more subtle ontogenetic changes.

  7. 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.

  8. Scales

    ScienceCinema

    Murray Gibson

    2016-07-12

    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).

  9. 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).

  10. The relationship between religiosity and cardiovascular risk factors in Japan: a large–scale cohort study

    PubMed Central

    Kobayashi, Daiki; Shimbo, Takuro; Takahashi, Osamu; Davis, Roger B.; Wee, Christina C.

    2015-01-01

    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

  11. 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.

  12. 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

  13. 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.

  14. Scale dependence of structure-function relationship in the emphysematous mouse lung

    PubMed Central

    Sato, Susumu; Bartolák-Suki, Erzsébet; Parameswaran, Harikrishnan; Hamakawa, Hiroshi; Suki, Béla

    2015-01-01

    The purpose of this study was to determine how the initial distribution of elastase in mouse lungs determines the time course of tissue destruction and how structural heterogeneity at different spatial scales influences lung function. We evaluated lung function and alveolar structure in normal and emphysematous C57BL/6 mice at 2 and 21 days following orotracheal treatment with porcine pancreatic elastase (PPE). Initial distribution of elastase 1 h after treatment was assessed using red fluorescently labeled PPE (f-PPE) by laser scanning confocal microscopy. From measured input impedance of the respiratory system, the global lung compliance, and the variability of regional compliance were obtained. Lungs were fixed and equivalent airspace diameters were measured in four lobes of the right lung and three regions of the left lung. At day 2 and day 21, the mean airspace diameter of each region was significantly enlarged which was accompanied by an increased inter-regional heterogeneity. The deposition of f-PPE on day 0 was much more heterogeneous than the inter-regional diameters at both day 2 and day 21 and, at day 21, this reached statistical significance (p < 0.05). Microscale heterogeneity characterized by the overall variability of airspace diameters correlated significantly better with compliance than macroscale or inter-regional heterogeneity. Furthermore, while the spatial distribution of the inflammatory response does not seem to follow that of the elastase deposition, it correlates with the strongest regional determinant of lung function. These results may help interpret lung function decline in terms of structural deterioration in human patients with emphysema. PMID:26029115

  15. Scale dependence of structure-function relationship in the emphysematous mouse lung.

    PubMed

    Sato, Susumu; Bartolák-Suki, Erzsébet; Parameswaran, Harikrishnan; Hamakawa, Hiroshi; Suki, Béla

    2015-01-01

    The purpose of this study was to determine how the initial distribution of elastase in mouse lungs determines the time course of tissue destruction and how structural heterogeneity at different spatial scales influences lung function. We evaluated lung function and alveolar structure in normal and emphysematous C57BL/6 mice at 2 and 21 days following orotracheal treatment with porcine pancreatic elastase (PPE). Initial distribution of elastase 1 h after treatment was assessed using red fluorescently labeled PPE (f-PPE) by laser scanning confocal microscopy. From measured input impedance of the respiratory system, the global lung compliance, and the variability of regional compliance were obtained. Lungs were fixed and equivalent airspace diameters were measured in four lobes of the right lung and three regions of the left lung. At day 2 and day 21, the mean airspace diameter of each region was significantly enlarged which was accompanied by an increased inter-regional heterogeneity. The deposition of f-PPE on day 0 was much more heterogeneous than the inter-regional diameters at both day 2 and day 21 and, at day 21, this reached statistical significance (p < 0.05). Microscale heterogeneity characterized by the overall variability of airspace diameters correlated significantly better with compliance than macroscale or inter-regional heterogeneity. Furthermore, while the spatial distribution of the inflammatory response does not seem to follow that of the elastase deposition, it correlates with the strongest regional determinant of lung function. These results may help interpret lung function decline in terms of structural deterioration in human patients with emphysema.

  16. Relationship between the Arctic oscillation and surface air temperature in multi-decadal time-scale

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroshi L.; Tamura, Mina

    2016-09-01

    In this study, a simple energy balance model (EBM) was integrated in time, considering a hypothetical long-term variability in ice-albedo feedback mimicking the observed multi-decadal temperature variability. A natural variability was superimposed on a linear warming trend due to the increasing radiative forcing of CO2. The result demonstrates that the superposition of the natural variability and the background linear trend can offset with each other to show the warming hiatus for some period. It is also stressed that the rapid warming during 1970-2000 can be explained by the superposition of the natural variability and the background linear trend at least within the simple model. The key process of the fluctuating planetary albedo in multi-decadal time scale is investigated using the JRA-55 reanalysis data. It is found that the planetary albedo increased for 1958-1970, decreased for 1970-2000, and increased for 2000-2012, as expected by the simple EBM experiments. The multi-decadal variability in the planetary albedo is compared with the time series of the AO mode and Barents Sea mode of surface air temperature. It is shown that the recent AO negative pattern showing warm Arctic and cold mid-latitudes is in good agreement with planetary albedo change indicating negative anomaly in high latitudes and positive anomaly in mid-latitudes. Moreover, the Barents Sea mode with the warm Barents Sea and cold mid-latitudes shows long-term variability similar to planetary albedo change. Although further studies are needed, the natural variabilities of both the AO mode and Barents Sea mode indicate some possible link to the planetary albedo as suggested by the simple EBM to cause the warming hiatus in recent years.

  17. Ecological relationships of meso-scale distribution in 25 neotropical vertebrate species.

    PubMed

    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

  18. 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

  19. The Cyber Aggression in Relationships Scale: A New Multidimensional Measure of Technology-Based Intimate Partner Aggression.

    PubMed

    Watkins, Laura E; Maldonado, Rosalita C; DiLillo, David

    2016-09-02

    The purpose of this study was to develop and provide initial validation for a measure of adult cyber intimate partner aggression (IPA): the Cyber Aggression in Relationships Scale (CARS). Drawing on recent conceptual models of cyber IPA, items from previous research exploring general cyber aggression and cyber IPA were modified and new items were generated for inclusion in the CARS. Two samples of adults 18 years or older were recruited online. We used item factor analysis to test the factor structure, model fit, and invariance of the measure structure across women and men. Results confirmed that three-factor models for both perpetration and victimization demonstrated good model fit, and that, in general, the CARS measures partner cyber aggression similarly for women and men. The CARS also demonstrated validity through significant associations with in-person IPA, trait anger, and jealousy. Findings suggest the CARS is a useful tool for assessing cyber IPA in both research and clinical settings.

  20. The global deterioration scale: relationships to neuropsychological performance and activities of daily living in patients with vascular dementia.

    PubMed

    Paul, Robert H; Cohen, Ronald A; Moser, David J; Zawacki, Tricia; Ott, Brian R; Gordon, Norman; Stone, William

    2002-01-01

    In the present study, we examined the relationships between ratings on the Global Deterioration Scale (GDS) and activities of daily living and cognitive function in 39 individuals with vascular dementia (VaD). The results of the study revealed significant correlations between GDS rating and performance on cognitive tests, including memory and overall cognitive ability. In addition, the GDS was significantly related to ratings of instrumental activities of daily living. Comparisons between patients with VaD with GDS scores between 4 and 6 (n = 21) and patients with scores between 2 and 3 (n = 18) revealed greater cognitive and functional deficits in the group with higher GDS scores. Further, the GDS score accurately classified 87% of the patients with VaD. These findings provide support for the validity of the GDS in general staging of dementia severity of VaD.

  1. An Examination of Not-For-Profit Stakeholder Networks for Relationship Management: A Small-Scale Analysis on Social Media.

    PubMed

    Wyllie, Jessica; Lucas, Benjamin; Carlson, Jamie; Kitchens, Brent; Kozary, Ben; Zaki, Mohamed

    2016-01-01

    Using a small-scale descriptive network analysis approach, this study highlights the importance of stakeholder networks for identifying valuable stakeholders and the management of existing stakeholders in the context of mental health not-for-profit services. We extract network data from the social media brand pages of three health service organizations from the U.S., U.K., and Australia, to visually map networks of 579 social media brand pages (represented by nodes), connected by 5,600 edges. This network data is analyzed using a collection of popular graph analysis techniques to assess the differences in the way each of the service organizations manage stakeholder networks. We also compare node meta-information against basic topology measures to emphasize the importance of effectively managing relationships with stakeholders who have large external audiences. Implications and future research directions are also discussed.

  2. An Examination of Not-For-Profit Stakeholder Networks for Relationship Management: A Small-Scale Analysis on Social Media

    PubMed Central

    Carlson, Jamie; Kitchens, Brent; Kozary, Ben; Zaki, Mohamed

    2016-01-01

    Using a small-scale descriptive network analysis approach, this study highlights the importance of stakeholder networks for identifying valuable stakeholders and the management of existing stakeholders in the context of mental health not-for-profit services. We extract network data from the social media brand pages of three health service organizations from the U.S., U.K., and Australia, to visually map networks of 579 social media brand pages (represented by nodes), connected by 5,600 edges. This network data is analyzed using a collection of popular graph analysis techniques to assess the differences in the way each of the service organizations manage stakeholder networks. We also compare node meta-information against basic topology measures to emphasize the importance of effectively managing relationships with stakeholders who have large external audiences. Implications and future research directions are also discussed. PMID:27711236

  3. 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.

  4. 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

  5. Water supply and demand remain coordinated during breakdown of the global scaling relationship between leaf size and major vein density.

    PubMed

    Schneider, Julio V; Habersetzer, Jörg; Rabenstein, Renate; Wesenberg, Jens; Wesche, Karsten; Zizka, Georg

    2017-04-01

    Vein networks that disobey the global scaling of major vein density with leaf size shed light on functional constraints of vein network formation in dicotyledons. Understanding their evolution, distribution and impact on vein-stomata-climate associations is an important contribution to our global view of vein network organization. Based on vein traits of 55 species of pantropical Ochnaceae, stomata and climatic niche data, and a dated molecular phylogeny, we unveil major structural shifts in vein networks through deep time, relationships between leaf size, vein and stomata traits, and their interplay with climate. Dense 2° veins, reduction of minor veins and the associated breakdown of vein-leaf size scaling evolved multiple times independently in Ochnaceae. In spite of the drastic changes in vein architecture in this venation type, vein and stomatal densities remain correlated. Our study demonstrates that shortening the major vein-stomata distance is economically not less advantageous than by increasing minor vein density, as illustrated by the same degree of coordination between vein and stomatal densities and the similar construction costs across networks with dense 2° veins and those with 'normally' spaced 2° veins.

  6. 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.

  7. Whole-bone scaling of the avian pelvic limb.

    PubMed

    Doube, Michael; Yen, Stephanie C W; Kłosowski, Michał M; Farke, Andrew A; Hutchinson, John R; Shefelbine, Sandra J

    2012-07-01

    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.

  8. Examining the relationship between intermediate-scale soil moisture and terrestrial evaporation within a semi-arid grassland

    NASA Astrophysics Data System (ADS)

    Jana, Raghavendra B.; Ershadi, Ali; McCabe, Matthew F.

    2016-09-01

    Interactions between soil moisture and terrestrial evaporation affect water cycle behaviour and responses between the land surface and the atmosphere across scales. With strong heterogeneities at the land surface, the inherent spatial variability in soil moisture makes its representation via point-scale measurements challenging, resulting in scale mismatch when compared to coarser-resolution satellite-based soil moisture or evaporation estimates. The Cosmic Ray Neutron Probe (CRNP) was developed to address such issues in the measurement and representation of soil moisture at intermediate scales. Here, we present a study to assess the utility of CRNP soil moisture observations in validating model evaporation estimates. The CRNP soil moisture product from a pasture in the semi-arid central west region of New South Wales, Australia, was compared to evaporation derived from three distinct approaches, including the Priestley-Taylor (PT-JPL), Penman-Monteith (PM-Mu), and Surface Energy Balance System (SEBS) models, driven by forcing data from local meteorological station data and remote sensing retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Pearson's correlations, quantile-quantile (Q-Q) plots, and analysis of variance (ANOVA) were used to qualitatively and quantitatively evaluate the temporal distributions of soil moisture and evaporation over the study site. The relationships were examined against nearly 2 years of observation data, as well as for different seasons and for defined periods of analysis. Results highlight that while direct correlations of raw data were not particularly instructive, the Q-Q plots and ANOVA illustrate that the root-zone soil moisture represented by the CRNP measurements and the modelled evaporation estimates reflect similar distributions under most meteorological conditions. The PT-JPL and PM-Mu model estimates performed contrary to expectation when high soil moisture and cold temperatures were present

  9. Variation in the cranium shape of wall lizards (Podarcis spp.): effects of phylogenetic constraints, allometric constraints and ecology.

    PubMed

    Urošević, Aleksandar; Ljubisavljević, Katarina; Jelić, Dušan; Ivanović, Ana

    2012-08-01

    We used geometric morphometrics to explore the influence of phylogenetic and allometric constraints as well as ecology on variation in cranium shape in five species of monophyletic, morphologically similar Podarcis lizards (Podarcis erhardii, Podarcis melisellensis, Podarcis muralis, Podarcis sicula and Podarcis taurica). These species belong to different clades, they differ in their habitat preferences and can be classified into two distinct morphotypes: saxicolous and terrestrial. We found (i) no phylogenetic signal in cranium shape, (ii) diverging allometric slopes among species, and (iii) a significant effect of habitat on cranium shape. The saxicolous species (P. erhardii and P. muralis) had crania with elongated parietals, elongated cranium bases, shortened anterior parts of the dorsal cranium, reduced chambers of the jaw adductor muscles and larger subocular foramina. These cranial features are adaptations that compensate for a flattened cranium, dwelling on vertical surfaces and seeking refuge in crevices. The crania of the terrestrial species (P. melisellensis, P. sicula and P. taurica) tended to be more elongate and robust, with enlarged chambers of the jaw adductor muscle, reduced skull bases and shortened parietals. Terrestrial species exhibited more variation in cranium shape than saxicolous species. Our study suggests that shape variation in Podarcis sp. lizards is largely influenced by ecology, which likely affects species-specific patterns of static allometry.

  10. Allometric dependence of the life span of mammal erythrocytes on thermal stability and sphingomyelin content of plasma membranes.

    PubMed

    Ivanov, Ivan Tanev

    2007-08-01

    Thermal stability of erythrocyte membrane is a measure for its ability to maintain permeability barrier at deleterious conditions. Hence, it could impact the resistance of erythrocytes against detrimental factors in circulation. In this study the thermostability of erythrocyte membranes was expressed by the temperature, T(go), at which the transmembrane gradient of ion concentration rapidly dissipated during transient heating. T(go) is the inducing temperature of the membrane transition that activated passive ion permeability at hyperthermia causing thermal hemolysis. A good allometric correlation of T(go) to the resistance against thermal hemolysis and the life span of erythrocytes were found for 13 mammals; sheep, cow, goat, dog, horse, man, rabbit, pig, cat, hamster, guinea pig, rat, and mouse. For the same group, the values of T(go) were strictly related to the sphingomyelin content of erythrocyte membranes. The residual ion permeability, P, was temperature activated from 38 to 57 degrees C with activation energy of 250+/-15 kJ/mol that strongly differed from that below 37 degrees C. The projected value of P at 37 degrees C was about half that of residual physiological permeability for Na+ and K+ that build ground for possible explanation of the life span vs membrane thermostability allometric correlation.

  11. 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.

  12. 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.

  13. The Uses of Texting in Sexual Relationships Scale: Associations With Risky Sexual Behavior Among At-Risk African American Emerging Adults.

    PubMed

    Broaddus, Michelle; Dickson-Gomez, Julia

    2016-10-01

    Qualitative and quantitative research was used to create the Uses of Texting in Sexual Relationships scale. At-risk, predominantly African American emerging adults participated in qualitative interviews (N = 20) and quantitative surveys (N = 110) about their uses of text messaging within romantic and sexual relationships. Exploratory factor analysis of items generated from interviews resulted in four subscales: Sexting, Relationship Maintenance, Relationship Development, and Texting for Sexual Safety. Exploratory analyses indicated associations of Sexting with more instances of condomless sex, and Texting for Sexual Safety with fewer instances of condomless sex, which was moderated by relationship power. Further research on the connections between text messaging in relationships and sexual behavior among high-risk and minority young adults is warranted, and intervention efforts to decrease sexual risks need to incorporate these avenues of sexual communication.

  14. 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.

  15. Relationship between grip strength and newly diagnosed nonalcoholic fatty liver disease in a large-scale adult population

    PubMed Central

    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

  16. 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

  17. An analysis of epipubic bone function in mammals using scaling theory.

    PubMed

    White, T D

    1989-08-09

    Linear dimensions of epipubic bones in 61 species of metatherians and monotremes scale to mass differently in groups with or without marsupia, presumably reflecting emphasis on different but non-mutually exclusive functions. Sexual dimorphism of epipubic form exists. However, the allometric relationships of the epipubic bones of taxa that possess marsupia do not conform to the hypothesis that epipubic bones support the marsupium nearly as well as those without a marsupium. This observation renders a new hypothesis relating litter mass to epipubic form in taxa without marsupia. It appears that support of the marsupium is not the primary function or, at least, not the most proximate determinate of epipubic form in taxa with marsupia. The scaling of epipubic bone dimensions is consistent with the hypothesis that predicts epipubic bones serve to assist in locomotion by acting with the hypaxial muscles of the trunk and pectineus to protract the pelvic limbs. Epipubic length is shown to scale to maintain a mechanical advantage between these opposing muscle groups that approximates the rate that inertia of the hind limbs increases with total mass and speed of locomotion. This hypothesis provides an explanation for a skeletal element scaling significantly above geometric similarity. This observation has important theoretical significance as it suggests that skeletal architecture may, within limits, scale independently of mass-related stress.

  18. Temperature effects on mass-scaling exponents in colonial animals: a manipulative test.

    PubMed

    Barneche, Diego R; White, Craig R; Marshall, Dustin J

    2017-01-01

    Body size and temperature are fundamental drivers of ecological processes because they determine metabolic rates at the individual level. Whether these drivers act independently on individual-level metabolic rates remains uncertain. Most studies of intraspecific scaling of unitary organisms must rely on preexisting differences in size to examine its relationship with metabolic rate, thereby potentially confounding size-correlated traits (e.g., age, nutrition) with size, which can affect metabolic rate. Here, we use a size manipulation approach to test whether metabolic mass scaling and temperature dependence interact in four species (two phyla) of colonial marine invertebrates. Size manipulation in colonial organisms allows tests of how ecological processes (e.g., predation) affect individual physiology and consequently population- and community-level energy flux. Body mass and temperature interacted in two species, with one species exhibiting decreased and the other increased mass-scaling exponents with increasing temperature. The allometric scaling of metabolic rate that we observe in three species contrasts with the isometric scaling of ingestion rates observed in some colonial marine invertebrates. Thus, we suggest that the often observed competitive superiority of colonial over unitary organisms may arise because the difference between energy intake and expenditure increases more strongly with size in colonial organisms.

  19. Validating the Student-Teacher Relationship Scale: testing factor structure and measurement invariance across child gender and age in a Dutch sample.

    PubMed

    Koomen, Helma M Y; Verschueren, Karine; van Schooten, Erik; Jak, Suzanne; Pianta, Robert C

    2012-04-01

    The Student-Teacher Relationship Scale (STRS) is widely used to examine teachers' relationships with young students in terms of closeness, conflict, and dependency. This study aimed to verify the dimensional structure of the STRS with confirmatory factor analysis, test its measurement invariance across child gender and age, improve its measurement of the dependency construct, and extend its age range. Teachers completed a slightly adapted STRS for a Dutch sample of 2335 children aged 3 to 12. Overall, the 3-factor model showed an acceptable fit. Results indicated metric invariance across gender and age up to 8years. Scalar invariance generally did not hold. Lack of metric invariance at ages 8 to 12 primarily involved Conflict items, whereas scale differences across gender and age primarily involved Closeness items. The adapted Dependency scale showed strong invariance and higher internal consistencies than the original scale for this Dutch sample. Importantly, the revealed non-invariance for gender and age did not influence mean group comparisons.

  20. High-frequency daily temperature variability in China and its relationship to large-scale circulation

    SciTech Connect

    Wu, Fu-Ting; Fu, Congbin; Qian, Yun; Gao, Yang; Wang, Shu-Yu

    2016-04-18

    Two measures of intra-seasonal variability, indicated respectively by standard deviations (SD) and day-to-day (DTD) fluctuations denoted by absolute differences between adjacent 2-day periods, as well as their relationships with large-scale circulation patterns were investigated in China during 1962–2008 on the basis of homogenized daily temperature records from 549 local stations and reanalysis data. Our results show that both the SD and DTD of daily minimum temperatures (Tmin) in summer as well as the minimum and maximum temperatures in winter have been decreasing, while the daily maximum temperature (Tmax) variability in summer is fluctuating more, especially over southern China. In summer, an attribution analysis indicates that the intensity of the Western Pacific Subtropical High (WPSH) and high-level East Asian Subtropical Jet stream (EASJ) are positively correlated with both SD and DTD, but the correlation coefficients are generally greater with the SD than with the DTD of the daily maximum temperature, Tmax. In contrast, the location of the EASJ shows the opposite correlation pattern, with intensity regarding the correlation with both SD and DTD. In winter, the Arctic Oscillation (AO) is negatively correlated with both the SD and DTD of the daily minimum temperature, but its intra-seasonal variability exhibits good agreement with the SD of the Tmin. The Siberian High acts differently with respect to the SD and DTD of the Tmin, demonstrating a regionally consistent positive correlation with the SD. Overall, the large-scale circulation can well explain the intra-seasonal SD, but DTD fluctuations may be more local and impacted by local conditions, such as changes in the temperature itself, the land surface, and so on.

  1. 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

  2. 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

  3. 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.

  4. Roles of Spatial Scale and Rarity on the Relationship between Butterfly Species Richness and Human Density in South Africa.

    PubMed

    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.

  5. 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

  6. 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.

  7. 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.

  8. Ontogenetic scaling of bite force in lizards and turtles.

    PubMed

    Herrel, Anthony; O'reilly, James C

    2006-01-01

    Because selection on juvenile life-history stages is likely strong, disproportionately high levels of performance (e.g., sprint speed, endurance, etc.) might be expected. Whereas this phenomenon has been demonstrated with respect to locomotor performance, data for feeding are scarce. Here, we investigate the relationships among body dimensions, head dimensions, and bite force during growth in lizards and turtles. We also investigate whether ontogenetic changes in bite performance are related to changes in diet. Our analyses show that, for turtles, head dimensions generally increase with negative allometry. For lizards, heads scale as expected for geometrically growing systems. Bite force generally increased isometrically with carapace length in turtles but showed significant positive allometry relative to body dimensions in lizards. However, both lizards and turtles display positive allometric scaling of bite force relative to some measures of head size throughout ontogeny, suggesting (1) strong selection for increased relative bite performance with increasing head size and (2) intrinsic changes in the geometry and/or mass of the jaw adductors during growth. Whereas our data generally do not provide strong evidence of compensation for lower absolute levels of performance, they do show strong links among morphology, bite force, and diet during growth.

  9. 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.

  10. 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…

  11. 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.

  12. [Clinical Validation of the Caregiver-Child Socioemotional and Relationship Rating Scale (SIRS) for Child Behavior in a Preschool-Age Sample].

    PubMed

    Esins, Svenja; Müller, Jörg Michael; Romer, Georg; Wagner, Katharina; Achtergarde, Sandra

    2017-03-01

    Clinical Validation of the Caregiver-Child Socioemotional and Relationship Rating Scale (SIRS) for Child Behavior in a Preschool-Age Sample The description of child behavior in mother-child-interaction is important in early detection and treatment of psychiatric disorders in preschool children. The Caregiver-Child Socioemotional and Relationship Rating Scale (SIRS) may serve this diagnostic purpose. We aim to examine interrater-reliability of SIRS and concurrent, convergent, and discriminant validity to maternal behavior by Play-PAB, and a m