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Sample records for allometric scaling relations

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

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

    PubMed

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

    2005-05-01

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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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).

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  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 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.

  14. 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.

  15. 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.

  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. 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.

  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 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

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  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. 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.

  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. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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.

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

    PubMed

    Kelly, Clint D

    2015-08-01

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

  12. 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.

  13. Allometric relations of total volumes of prolactin cells and corticotropic cells to body length in the annual cyprinodont Cynolebias whitei: effects of environmental salinity, stress and ageing.

    PubMed

    Ruijter, J M; Wendelaar Bonga, S E

    1987-09-01

    An analysis of the allometric relations of the total volumes occupied by prolactin (PRL) and corticotropic (ACTH) cells (PRL volume and ACTH volume, respectively) to body length and a study of the immunocytochemical staining intensity of PRL and ACTH cells were used to determine the differences in activity of PRL and ACTH cells in freshwater-reared and in saltwater-reared Cynolebias whitei during the entire lifespan of this annual cyprinodont fish. An inflection in the allometric relation of PRL volume to body length was observed in fish of one-week old. The relatively large PRL volume in younger fish may be related to PRL cell activity before hatching. No inflections were observed in the allometric relations of PRL volume and ACTH volume to body length at the onset of maturation and the onset of ageing, indicating that the increased pituitary growth in maturing and ageing C. whitei is not the result of changes in PRL or ACTH cells. The slope of the allometric relation of PRL volume to body length in freshwater-reared fish was significantly steeper than the slope in saltwater-reared fish. The PRL volume in adult freshwater-reared fish was eight times larger than that in saltwater-reared fish of the same length. The intensity of immunocytochemical staining of saltwater PRL cells was significantly reduced. These volumetric and staining differences correspond to the low functional demand put upon PRL cells in saltwater-adapted fish. In contrast, the slope of the allometric relation of ACTH volume to body length and the intensity of immunocytochemical staining of ACTH cells were similar in freshwater-reared and in saltwater-reared fish.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. 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.

  15. 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.

  16. 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.

  17. Allometric growth rate of the spinal cord in relation to the vertebral column during prenatal life in male and female goats (Capra hircus).

    PubMed

    Ghazi, S M; Ranjbar, R; Khaksary Mahabady, M

    2016-01-01

    Total and regional allometric growth rates and termination sites of the spinal cord related to the respective vertebra were studied in 36 goat fetuses, from the Ahvaz slaughterhouse. These specimens were assigned to 3 groups, group 1 (CRL 10-20 cm), group 2 (CRL 21-30 cm), and group 3 (CRL 31-40 cm), each consisting of 6 male and 6 female fetuses. Observations in all 3 groups revealed that although the growth of the vertebral column was greater than that of the spinal cord, the difference in growth was not constant throughout the spine. While in cervical and thoracic regions the growth rate of the spinal cord in relation to the vertebral column was almost isometric, in the caudal part of the spine there was marked decline in growth of the spinal cord compared to the respective regions of the vertebral column. Craniocaudally, the allometric growth rate became drastically negative. There was no significant difference (P>0.05) between males and females. Except in thoracic region, all other regions showed significant differences (P<0.01) between similar regions in all 3 groups. In the lumbar region of group 2 no significant difference was found (P>0.05). As a consequence of the negative allometric growth of the spinal cord in relation to the vertebral column in the caudal part of the spine, the conus medullaris was displaced from S4-S5 in group 1 to S2 in group 3. No significant difference (P>0.05) between male and female fetuses concerning the termination of the spinal cord was found.

  18. Allometric growth rate of the spinal cord in relation to the vertebral column during prenatal life in male and female goats (Capra hircus)

    PubMed Central

    Ghazi, S. M.; Ranjbar, R.; Khaksary Mahabady, M.

    2016-01-01

    Total and regional allometric growth rates and termination sites of the spinal cord related to the respective vertebra were studied in 36 goat fetuses, from the Ahvaz slaughterhouse. These specimens were assigned to 3 groups, group 1 (CRL 10-20 cm), group 2 (CRL 21-30 cm), and group 3 (CRL 31-40 cm), each consisting of 6 male and 6 female fetuses. Observations in all 3 groups revealed that although the growth of the vertebral column was greater than that of the spinal cord, the difference in growth was not constant throughout the spine. While in cervical and thoracic regions the growth rate of the spinal cord in relation to the vertebral column was almost isometric, in the caudal part of the spine there was marked decline in growth of the spinal cord compared to the respective regions of the vertebral column. Craniocaudally, the allometric growth rate became drastically negative. There was no significant difference (P>0.05) between males and females. Except in thoracic region, all other regions showed significant differences (P<0.01) between similar regions in all 3 groups. In the lumbar region of group 2 no significant difference was found (P>0.05). As a consequence of the negative allometric growth of the spinal cord in relation to the vertebral column in the caudal part of the spine, the conus medullaris was displaced from S4-S5 in group 1 to S2 in group 3. No significant difference (P>0.05) between male and female fetuses concerning the termination of the spinal cord was found. PMID:28224007

  19. 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

  20. 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.

  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. 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

  3. 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

  4. 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.

  5. 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.

  6. Allometric growth and development of organs in ballan wrasse (Labrus bergylta Ascanius, 1767) larvae in relation to different live prey diets and growth rates

    PubMed Central

    Wold, Per-Arvid; Bardal, Tora; Øie, Gunvor; Kjørsvik, Elin

    2016-01-01

    ABSTRACT Small fish larvae grow allometrically, but little is known about how this growth pattern may be affected by different growth rates and early diet quality. The present study investigates how different growth rates, caused by start-feeding with copepods or rotifers the first 30 days post-hatch (dph), affect allometric growth and development of nine major organs in ballan wrasse (Labrus bergylta) larvae up to experimental end at 60 dph. Feeding with cultivated copepod nauplii led to both increased larval somatic growth and faster development and growth of organ systems than feeding with rotifers. Of the organs studied, the digestive and respiratory organs increased the most in size between 4 and 8 dph, having a daily specific growth rate (SGR) between 30 and 40% in larvae fed copepods compared with 20% or less for rotifer-fed larvae. Muscle growth was prioritised from flexion stage and onwards, with a daily SGR close to 30% between 21 and 33 dph regardless of treatment. All larvae demonstrated a positive linear correlation between larval standard length (SL) and increase in total tissue volume, and no difference in allometric growth pattern was found between the larval treatments. A change from positive allometric to isometric growth was observed at a SL close to 6.0 mm, a sign associated with the start of metamorphosis. This was also where the larvae reached postflexion stage, and was accompanied by a change in growth pattern for most of the major organ systems. The first sign of a developing hepatopancreas was, however, first observed in the largest larva (17.4 mm SL, 55 dph), indicating that the metamorphosis in ballan wrasse is a gradual process lasting from 6.0 to at least 15-17 mm SL. PMID:27422903

  7. Allometric growth and development of organs in ballan wrasse (Labrus bergylta Ascanius, 1767) larvae in relation to different live prey diets and growth rates.

    PubMed

    Gagnat, Maren Ranheim; Wold, Per-Arvid; Bardal, Tora; Øie, Gunvor; Kjørsvik, Elin

    2016-09-15

    Small fish larvae grow allometrically, but little is known about how this growth pattern may be affected by different growth rates and early diet quality. The present study investigates how different growth rates, caused by start-feeding with copepods or rotifers the first 30 days post-hatch (dph), affect allometric growth and development of nine major organs in ballan wrasse (Labrus bergylta) larvae up to experimental end at 60 dph. Feeding with cultivated copepod nauplii led to both increased larval somatic growth and faster development and growth of organ systems than feeding with rotifers. Of the organs studied, the digestive and respiratory organs increased the most in size between 4 and 8 dph, having a daily specific growth rate (SGR) between 30 and 40% in larvae fed copepods compared with 20% or less for rotifer-fed larvae. Muscle growth was prioritised from flexion stage and onwards, with a daily SGR close to 30% between 21 and 33 dph regardless of treatment. All larvae demonstrated a positive linear correlation between larval standard length (SL) and increase in total tissue volume, and no difference in allometric growth pattern was found between the larval treatments. A change from positive allometric to isometric growth was observed at a SL close to 6.0 mm, a sign associated with the start of metamorphosis. This was also where the larvae reached postflexion stage, and was accompanied by a change in growth pattern for most of the major organ systems. The first sign of a developing hepatopancreas was, however, first observed in the largest larva (17.4 mm SL, 55 dph), indicating that the metamorphosis in ballan wrasse is a gradual process lasting from 6.0 to at least 15-17 mm SL.

  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. 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.

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Scaling relations for magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Landeros, P.; Escrig, J.; Altbir, D.; Laroze, D.; D'Albuquerque E Castro, J.; Vargas, P.

    2005-03-01

    A detailed investigation of the scaling relations recently proposed [J. d’Albuquerque e Castro, D. Altbir, J. C. Retamal, and P. Vargas, Phys. Rev. Lett. 88, 237202 (2002)] to study the magnetic properties of nanoparticles is presented. Analytical expressions for the total energy of three characteristic internal configurations of the particles are obtained, in terms of which the behavior of the magnetic phase diagram for those particles upon scaling of the exchange interaction is discussed. The exponent η in scaling relations is shown to be dependent on the geometry of the vortex core, and results for specific cases are presented.

  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. 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

  19. 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.

  20. Children's Social Relations Interview Scale.

    ERIC Educational Resources Information Center

    Volpe, Richard

    The Children's Social Relations Interview Scale (CSRIS) was developed to assess the role expectations and role behaviors associated with physical disabilities, namely low status and independence. Three traits are assessed: succorance, the seeking of help and support; restraint, physical and social limitation and circumscription by others; and…

  1. 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.

  2. Mirages in galaxy scaling relations

    NASA Astrophysics Data System (ADS)

    Mosenkov, A. V.; Sotnikova, N. Ya.; Reshetnikov, V. P.

    2014-06-01

    We analysed several basic correlations between structural parameters of galaxies. The data were taken from various samples in different passbands which are available in the literature. We discuss disc scaling relations as well as some debatable issues concerning the so-called Photometric Plane for bulges and elliptical galaxies in different forms and various versions of the famous Kormendy relation. We show that some of the correlations under discussion are artificial (self-correlations), while others truly reveal some new essential details of the structural properties of galaxies. Our main results are as follows: At present, we cannot conclude that faint stellar discs are, on average, more thin than discs in high surface brightness galaxies. The `central surface brightness-thickness' correlation appears only as a consequence of the transparent exponential disc model to describe real galaxy discs. The Photometric Plane appears to have no independent physical sense. Various forms of this plane are merely sophisticated versions of the Kormendy relation or of the self-relation involving the central surface brightness of a bulge/elliptical galaxy and the Sérsic index n. The Kormendy relation is a physical correlation presumably reflecting the difference in the origin of bright and faint ellipticals and bulges. We present arguments that involve creating artificial samples to prove our main idea.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Satellite-scale Estimates of the "b Parameter" Relating Vegetation Water Content and SMOS Optical Thickness

    NASA Astrophysics Data System (ADS)

    Patton, J. C.; Hornbuckle, B. K.

    2013-12-01

    Microwave radiation emitted by Earth's land surface is primarily determined by soil moisture and vegetation. One of the effects of vegetation on surface microwave emissions is often termed the "vegetation optical thickness" or "vegetation opacity" and is often abbreviated as tau. Retrievals of soil moisture from microwave radiometer measurements requires knowledge of tau. The Soil Moisture and Ocean Salinity (SMOS) satellite measures microwave radiation at multiple incidence angles, enabling the simultaneous retrieval of soil moisture and tau. Other soil moisture satellites, such as the upcoming Soil Moisture Active Passive (SMAP) satellite, only measure at single incidence angles and may need auxiliary sources of tau data in order to retrieve soil moisture. One proposed method for estimating tau for these satellites is by relating reflectance data, e.g. the normalized difference vegetation index, to vegetation water content (VWC), then relating VWC to tau. VWC and tau can be related through the b parameter, i.e. tau = b x VWC. Values of b for different land cover types have been estimated from tower (~1 m) and airplane (~10-100 m) data, but have not been measured at the satellite scale (~10 km). Estimating b at the satellite scale from measurements at smaller scales is difficult because the effective value of b in a satellite pixel may not be well represented by linear weighted average based on the fraction of each land cover type in the pixel. However, by relating county crop yields, estimated by the USDA National Agricultural Statistics Service, to measurements of SMOS tau, and by using certain allometric relationships, such as the ratio of water to dry matter and the harvest index of crops, we can estimate b at the satellite scale. We have used this method to estimate b for each Iowa county for the years 2010-2012. Initial results suggest that b may change year to year; our current estimates for b in Iowa range from 0.065 in 2010 to 0.100 in 2012. These

  8. The Career-Related Parent Support Scale.

    ERIC Educational Resources Information Center

    Turner, Sherri L.; Alliman-Brissett, Annette; Lapan, Richard T.; Udipi, Sharanya; Ergun, Damla

    2003-01-01

    The authors describe the construction of the Career-Related Parent Support Scale and examine the validity of the scale scores within a sample of at-risk middle school adolescents. Four empirically distinct parent support factors were confirmed along A. Bandura's sources of self-efficacy information. Gender and ethnic differences in perceived…

  9. On the Evolution of Cluster Scaling Relations

    NASA Astrophysics Data System (ADS)

    Diemer, Benedikt; Kravtsov, Andrey V.; More, Surhud

    2013-12-01

    Understanding the evolution of scaling relations between the observable properties of clusters and their total mass is key to realizing their potential as cosmological probes. In this study, we investigate whether the evolution of cluster scaling relations is affected by the spurious evolution of mass caused by the evolving reference density with respect to which halo masses are defined (pseudo-evolution). We use the relation between mass, M, and velocity dispersion, σ, as a test case, and show that the deviation from the M-σ relation of cluster-sized halos caused by pseudo-evolution is smaller than 10% for a wide range of mass definitions. The reason for this small impact is a tight relation between the velocity dispersion and mass profiles, \\sigma ({<}r) = const \\times \\sqrt{{GM}({<}r) / r}, which holds across a wide range of radii. We show that such a relation is generically expected for a variety of density profiles, as long as halos are in approximate Jeans equilibrium. Thus, as the outer "virial" radius used to define the halo mass, R, increases due to pseudo-evolution, halos approximately preserve their M-σ relation. This result highlights the fact that tight scaling relations are the result of tight equilibrium relations between radial profiles of physical quantities. We find exceptions at very small and very large radii, where the profiles deviate from the relations they exhibit at intermediate radii. We discuss the implications of these results for other cluster scaling relations and argue that pseudo-evolution should have a small effect on most scaling relations, except for those that involve the stellar masses of galaxies. In particular, we show that the relation between stellar-mass fraction and total mass is affected by pseudo-evolution and is largely shaped by it for halo masses <~ 1014 M ⊙.

  10. On the evolution of cluster scaling relations

    SciTech Connect

    Diemer, Benedikt; Kravtsov, Andrey V.; More, Surhud

    2013-12-20

    Understanding the evolution of scaling relations between the observable properties of clusters and their total mass is key to realizing their potential as cosmological probes. In this study, we investigate whether the evolution of cluster scaling relations is affected by the spurious evolution of mass caused by the evolving reference density with respect to which halo masses are defined (pseudo-evolution). We use the relation between mass, M, and velocity dispersion, σ, as a test case, and show that the deviation from the M-σ relation of cluster-sized halos caused by pseudo-evolution is smaller than 10% for a wide range of mass definitions. The reason for this small impact is a tight relation between the velocity dispersion and mass profiles, σ(relation is generically expected for a variety of density profiles, as long as halos are in approximate Jeans equilibrium. Thus, as the outer 'virial' radius used to define the halo mass, R, increases due to pseudo-evolution, halos approximately preserve their M-σ relation. This result highlights the fact that tight scaling relations are the result of tight equilibrium relations between radial profiles of physical quantities. We find exceptions at very small and very large radii, where the profiles deviate from the relations they exhibit at intermediate radii. We discuss the implications of these results for other cluster scaling relations and argue that pseudo-evolution should have a small effect on most scaling relations, except for those that involve the stellar masses of galaxies. In particular, we show that the relation between stellar-mass fraction and total mass is affected by pseudo-evolution and is largely shaped by it for halo masses ≲ 10{sup 14} M {sub ☉}.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. Relative Atomic Mass Scale: A Teaching Aid.

    ERIC Educational Resources Information Center

    Baumgartner, Erwin; And Others

    1988-01-01

    Proposes the use of a relative atomic mass (RAM) scale in which hydrogen is assigned a value from one as a teaching aid for better understanding the concept of RAM. Helps to clarify the ideas and concepts about this topic. (CW)

  16. 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

  17. 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.

  18. Extended Scaling Relations for Planar Lattice Models

    NASA Astrophysics Data System (ADS)

    Benfatto, G.; Falco, P.; Mastropietro, V.

    2009-12-01

    It is widely believed that the critical properties of several planar lattice systems, like the Eight Vertex or the Ashkin-Teller models, are well described by an effective continuum fermionic theory obtained as a formal scaling limit. On the basis of this assumption several extended scaling relations among their indices were conjectured. We prove the validity of some of them, among which the ones predicted by Kadanoff (Phys Rev Lett 39:903-905, 1977) and by Luther and Peschel (Phys Rev B 12:3908-3917, 1975).

  19. 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.

  20. 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.

  1. Finite-fault scaling relations in Mexico

    NASA Astrophysics Data System (ADS)

    Rodríguez-Pérez, Quetzalcoatl; Ottemöller, Lars

    2013-06-01

    Earthquake source parameters are widely used for computing scaling laws. We estimated source parameters for earthquakes in the Gulf of California, and the Mexican subduction zone through teleseismic fault slip inversion. The scaling relations herein can provide useful information for studies focused on source characteristics and ground motions in Mexico. We derived source scaling relations to estimate fault dimensions, combined asperity area, ratio of combined asperity area to rupture area, maximum displacement, mean displacement, duration and seismic energy of subduction interplate earthquakes based on their moment magnitude. We do not developed scaling relationships for strike-slip events in the Gulf of California due to the reduced number of data, but compare source parameters. We analyzed differences in source parameters between the two types of earthquakes. Scaling relations were fitted with orthogonal regression and we analyzed the difference between our subduction zone relationships and previous ones. We determined 21 finite-fault slip distributions for earthquakes in the magnitude range of 6.5 < Mw < 8.0. We do not include solutions obtained from other authors based on different inversion methods to construct scaling relationships in a consistent manner. Within this study, we characterized heterogeneous slip models by determining source parameters on the asperities and on the background area, such as number of asperities, combined asperity area, stress drop on asperities, aspect ratio, strain and average stress drop. We found that the area of the asperities represented about 22 and 24 per cent of the total area for strike-slip, and reverse events respectively with two different criteria based on average slip and maximum displacement. Sensitivity tests were carried out to estimate the variability of slip patterns and source parameters by changing fault dimensions, subfault size and the number of stations. We observed robust slip solutions and reliable source

  2. Fundamental metallicity scaling relations in cosmological simulations

    NASA Astrophysics Data System (ADS)

    De Rossi, M. E.; Theuns, T.; Font, A. S.; McCarthy, I. G.

    2016-08-01

    In this work, we analyse metallicity scaling relations of galaxies by using Galaxies-Intergalactic Medium Interaction Calculation simulations. Our results show that stellar metallicity correlates with stellar mass, in agreement with observations. At a given mass, systems with lower gas fractions or lower star formation rates are, on average, more metal-enriched. In addition, satellite galaxies tend to have higher metallicities that central galaxies of similar masses. The relation between mass and stellar metallicity does not evolve significantly with redshift. These trends obtained for the stellar phase are weaker than those found for the gas component in previous studies.

  3. 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

  4. Scaling relations for galaxies prior to reionization

    SciTech Connect

    Chen, Pengfei; Norman, Michael L.; Xu, Hao; Wise, John H.; O'Shea, Brian W. E-mail: mlnorman@ucsd.edu E-mail: jwise@gatech.edu

    2014-11-10

    The first galaxies in the universe are the building blocks of all observed galaxies. We present scaling relations for galaxies forming at redshifts z ≥ 15 when reionization is just beginning. We utilize the 'Rarepeak' cosmological radiation hydrodynamics simulation that captures the complete star formation history in over 3300 galaxies, starting with massive Population III stars that form in dark matter halos as small as ∼10{sup 6} M {sub ☉}. We make various correlations between the bulk halo quantities, such as virial, gas, and stellar masses and metallicities and their respective accretion rates, quantifying a variety of properties of the first galaxies up to halo masses of 10{sup 9} M {sub ☉}. Galaxy formation is not solely relegated to atomic cooling halos with virial temperatures greater than 10{sup 4} K, where we find a dichotomy in galaxy properties between halos above and below this critical mass scale. Halos below the atomic cooling limit have a stellar mass-halo mass relationship log M {sub *} ≅ 3.5 + 1.3log (M {sub vir}/10{sup 7} M {sub ☉}). We find a non-monotonic relationship between metallicity and halo mass for the smallest galaxies. Their initial star formation events enrich the interstellar medium and subsequent star formation to a median of 10{sup –2} Z {sub ☉} and 10{sup –1.5} Z {sub ☉}, respectively, in halos of total mass 10{sup 7} M {sub ☉}, which is then diluted by metal-poor inflows well beyond Population III pre-enrichment levels of 10{sup –3.5} Z {sub ☉}. The scaling relations presented here can be employed in models of reionization, galaxy formation, and chemical evolution in order to consider these galaxies forming prior to reionization.

  5. Large-scale tides in general relativity

    NASA Astrophysics Data System (ADS)

    Ip, Hiu Yan; Schmidt, Fabian

    2017-02-01

    Density perturbations in cosmology, i.e. spherically symmetric adiabatic perturbations of a Friedmann-Lemaȋtre-Robertson-Walker (FLRW) spacetime, are locally exactly equivalent to a different FLRW solution, as long as their wavelength is much larger than the sound horizon of all fluid components. This fact is known as the "separate universe" paradigm. However, no such relation is known for anisotropic adiabatic perturbations, which correspond to an FLRW spacetime with large-scale tidal fields. Here, we provide a closed, fully relativistic set of evolutionary equations for the nonlinear evolution of such modes, based on the conformal Fermi (CFC) frame. We show explicitly that the tidal effects are encoded by the Weyl tensor, and are hence entirely different from an anisotropic Bianchi I spacetime, where the anisotropy is sourced by the Ricci tensor. In order to close the system, certain higher derivative terms have to be dropped. We show that this approximation is equivalent to the local tidal approximation of Hui and Bertschinger [1]. We also show that this very simple set of equations matches the exact evolution of the density field at second order, but fails at third and higher order. This provides a useful, easy-to-use framework for computing the fully relativistic growth of structure at second order.

  6. 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

  7. 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

  8. 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.

  9. Scaling Relation for Occulter Manufacturing Errors

    NASA Technical Reports Server (NTRS)

    Sirbu, Dan; Shaklan, Stuart B.; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2015-01-01

    For directly imaging exoplanets, NASA is considering space mission designs that use an external occulter as the principal starlight suppression system. These occulter designs range in diameter from 16 to 40 meters and separation distance from 8,000 to 60,000 kilometers for telescopes with primary diameters of 0.5 to 4 meters. Occulter shapes are solutions to an optimization problem which seeks to maximize suppression in the shadow subject to constraints such as size, separation, and wavelengths. These designs are based on scalar diffraction theory and must be verified experimentally to demonstrate predicted on-orbit performance. Due to the large sizes and separations involved the experiment must be scaled to lab size. We are currently expanding the existing experimental test-bed at Princeton to enable scaling of occulters operating at flight Fresnel sizes. Here we examine the effect on suppression performance of edge defects and their scaling to test-bed size.

  10. 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

  11. 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.

  12. 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.

  13. Scaling Relation for Occulter Manufacturing Errors

    NASA Technical Reports Server (NTRS)

    Sirbu, Dan; Shaklan, Stuart B.; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2015-01-01

    An external occulter is a spacecraft own along the line-of-sight of a space telescope to suppress starlight and enable high-contrast direct imaging of exoplanets. The shape of an external occulter must be specially designed to optimally suppress starlight and deviations from the ideal shape due to manufacturing errors can result loss of suppression in the shadow. Due to the long separation distances and large dimensions involved for a space occulter, laboratory testing is conducted with scaled versions of occulters etched on silicon wafers. Using numerical simulations for a flight Fresnel occulter design, we show how the suppression performance of an occulter mask scales with the available propagation distance for expected random manufacturing defects along the edge of the occulter petal. We derive an analytical model for predicting performance due to such manufacturing defects across the petal edges of an occulter mask and compare this with the numerical simulations. We discuss the scaling of an extended occulter test-bed.

  14. 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.

  15. 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.

  16. Special relativity at the quantum scale.

    PubMed

    Lam, Pui K

    2014-01-01

    It has been suggested that the space-time structure as described by the theory of special relativity is a macroscopic manifestation of a more fundamental quantum structure (pre-geometry). Efforts to quantify this idea have come mainly from the area of abstract quantum logic theory. Here we present a preliminary attempt to develop a quantum formulation of special relativity based on a model that retains some geometric attributes. Our model is Feynman's "checker-board" trajectory for a 1-D relativistic free particle. We use this model to guide us in identifying (1) the quantum version of the postulates of special relativity and (2) the appropriate quantum "coordinates". This model possesses a useful feature that it admits an interpretation both in terms of paths in space-time and in terms of quantum states. Based on the quantum version of the postulates, we derive a transformation rule for velocity. This rule reduces to the Einstein's velocity-addition formula in the macroscopic limit and reveals an interesting aspect of time. The 3-D case, time-dilation effect, and invariant interval are also discussed in term of this new formulation. This is a preliminary investigation; some results are derived, while others are interesting observations at this point.

  17. Special Relativity at the Quantum Scale

    PubMed Central

    Lam, Pui K.

    2014-01-01

    It has been suggested that the space-time structure as described by the theory of special relativity is a macroscopic manifestation of a more fundamental quantum structure (pre-geometry). Efforts to quantify this idea have come mainly from the area of abstract quantum logic theory. Here we present a preliminary attempt to develop a quantum formulation of special relativity based on a model that retains some geometric attributes. Our model is Feynman's “checker-board” trajectory for a 1-D relativistic free particle. We use this model to guide us in identifying (1) the quantum version of the postulates of special relativity and (2) the appropriate quantum “coordinates”. This model possesses a useful feature that it admits an interpretation both in terms of paths in space-time and in terms of quantum states. Based on the quantum version of the postulates, we derive a transformation rule for velocity. This rule reduces to the Einstein's velocity-addition formula in the macroscopic limit and reveals an interesting aspect of time. The 3-D case, time-dilation effect, and invariant interval are also discussed in term of this new formulation. This is a preliminary investigation; some results are derived, while others are interesting observations at this point. PMID:25531675

  18. Amplitudes of solar-like oscillations: a new scaling relation

    NASA Astrophysics Data System (ADS)

    Kjeldsen, H.; Bedding, T. R.

    2011-05-01

    Solar-like oscillations are excited by near-surface convection and are being observed in growing numbers of stars using ground- and space-based telescopes. We have previously suggested an empirical scaling relation to predict their amplitudes. This relation has found widespread use but it predicts amplitudes in F-type stars that are higher than observed. Here we present a new scaling relation that is based on the postulate that the power in velocity fluctuations due to p-mode oscillations scales with stellar parameters in the same way as the power in velocity fluctuations due to granulation. The new relation includes a dependence on the damping rate via the mode lifetime and should be testable using observations from the CoRoT and Kepler missions. We also suggest scaling relations for the properties of the background power due to granulation and argue that both these and the amplitude relations should be applicable to red giant stars.

  19. Developing scaling relations for the yield strength of nanoporous gold

    NASA Astrophysics Data System (ADS)

    Briot, Nicolas J.; Balk, T. John

    2015-09-01

    In this work, the applicability of Gibson and Ashby's porous scaling relations to nanoporous metals is discussed, and an updated equation is proposed for relating the yield strength of nanoporous gold to the yield strength of individual gold ligaments that form the porous structure. This new relation is derived from experimental measurements obtained by small-scale tensile testing and by nanoindentation, and incorporates the average ligament diameter. Nanoindentation data, obtained experimentally by the authors as well as reported by others in the literature, are reconciled with tensile test measurements previously reported by the present authors. The values of ligament yield strength calculated with the new scaling relation are found to agree with data reported from mechanical testing of nanowires, and the scaling relation thus represents a bridge between nanowire and nanoporous metal behaviour. In addition, calculations of yield strength for nanoporous gold samples with various ligament size and relative density are consistent with the experimentally determined values.

  20. Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach.

    PubMed

    Genet, H; Bréda, N; Dufrêne, E

    2010-02-01

    Two types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root:shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m(-)(2) year(-1) at 30 years old to 129 gC m(-2) year(-1) at 138 years old. In beech, carbon allocation to storage and

  1. PICACS: self-consistent modelling of galaxy cluster scaling relations

    NASA Astrophysics Data System (ADS)

    Maughan, B. J.

    2014-01-01

    In this paper, we introduce Physically motivated, Internally Consistent Analysis of Cluster Scaling (PICACS), a detailed model of scaling relations between galaxy cluster masses and their observable properties. This model can be used to constrain simultaneously the form, scatter (including its covariance) and evolution of the scaling relations, as well as the masses of the individual clusters. In this framework, scaling relations between observables (such as that between X-ray luminosity and temperature) are modelled explicitly in terms of the fundamental mass-observable scaling relations, and so are fully constrained without being fit directly. We apply the PICACS model to two observational data sets, and show that it performs as well as traditional regression methods for simply measuring individual scaling relation parameters, but reveals additional information on the processes that shape the relations while providing self-consistent mass constraints. Our analysis suggests that the observed combination of slopes of the scaling relations can be described by a deficit of gas in low-mass clusters that is compensated for by elevated gas temperatures, such that the total thermal energy of the gas in a cluster of given mass remains close to self-similar expectations. This is interpreted as the result of AGN feedback removing low entropy gas from low-mass systems, while heating the remaining gas. We deconstruct the luminosity-temperature (L-T) relation and show that its steepening compared to self-similar expectations can be explained solely by this combination of gas depletion and heating in low-mass systems, without any additional contribution from a mass dependence of the gas structure. Finally, we demonstrate that a self-consistent analysis of the scaling relations leads to an expectation of self-similar evolution of the L-T relation that is significantly weaker than is commonly assumed.

  2. Testing general relativity: from local to cosmological scales.

    PubMed

    Uzan, Jean-Philippe

    2011-12-28

    I summarize various tests of general relativity on astrophysical scales, based on the large-scale structure of the universe but also on other systems, in particular the constants of physics. I emphasize the importance of hypotheses on the geometric structures of our universe while performing such tests and discuss their complementarity as well as their possible extensions.

  3. 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.

  4. Utility-scale system preventive and failure-related maintenance

    SciTech Connect

    Jennings, C.; Hutchinson, P.

    1995-11-01

    This paper describes the design and performance background on PVUSA utility-scale systems at Davis and Kerman, California, and reports on a preventative and failure-related maintenance approach and costs.

  5. Non-Abelian gauge field theory in scale relativity

    SciTech Connect

    Nottale, Laurent; Celerier, Marie-Noeelle; Lehner, Thierry

    2006-03-15

    Gauge field theory is developed in the framework of scale relativity. In this theory, space-time is described as a nondifferentiable continuum, which implies it is fractal, i.e., explicitly dependent on internal scale variables. Owing to the principle of relativity that has been extended to scales, these scale variables can themselves become functions of the space-time coordinates. Therefore, a coupling is expected between displacements in the fractal space-time and the transformations of these scale variables. In previous works, an Abelian gauge theory (electromagnetism) has been derived as a consequence of this coupling for global dilations and/or contractions. We consider here more general transformations of the scale variables by taking into account separate dilations for each of them, which yield non-Abelian gauge theories. We identify these transformations with the usual gauge transformations. The gauge fields naturally appear as a new geometric contribution to the total variation of the action involving these scale variables, while the gauge charges emerge as the generators of the scale transformation group. A generalized action is identified with the scale-relativistic invariant. The gauge charges are the conservative quantities, conjugates of the scale variables through the action, which find their origin in the symmetries of the ''scale-space.'' We thus found in a geometric way and recover the expression for the covariant derivative of gauge theory. Adding the requirement that under the scale transformations the fermion multiplets and the boson fields transform such that the derived Lagrangian remains invariant, we obtain gauge theories as a consequence of scale symmetries issued from a geometric space-time description.

  6. 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

  7. 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.

  8. On Scaling Relations of Organic Antiferromagnets with Magnetic Anions

    NASA Astrophysics Data System (ADS)

    Shimahara, Hiroshi; Kono, Yuki

    2017-04-01

    We study a recently reported scaling relation of the specific heat of the organic compounds λ-(BETS)2FexGa1-xCl4. This relation suggests that the sublattice magnetization m of the π electrons and the antiferromagnetic transition temperature TN are proportional to x. Note that the scaling relation for TN can be explained by considering the effective interaction between the π electrons via the localized 3d spins on the FeCl4 anions. The effective interaction is analogous to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, but the roles of the conductive electrons and the localized spins are interchanged. Using available energy scales, it is shown that the TN scaling relation indicates that the system is in the vicinity of the quantum critical point. It is argued that the scaling relation for m at low temperatures, i.e., below TN but excluding temperatures in the vicinity of TN, indicates that the mismatch between the Fermi surface and that shifted by the nesting vector is large, at least for a large part of the Fermi surface. We also discuss the scaling relation near TN.

  9. SMALL-SCALE ANISOTROPIES OF COSMIC RAYS FROM RELATIVE DIFFUSION

    SciTech Connect

    Ahlers, Markus; Mertsch, Philipp

    2015-12-10

    The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small-scale structure can naturally arise from cosmic ray scattering in local turbulent magnetic fields that distort a global dipole anisotropy set by diffusion. We study this effect in terms of the power spectrum of cosmic ray arrival directions and show that the strength of small-scale anisotropies is related to properties of relative diffusion. We provide a formalism for how these power spectra can be inferred from simulations and motivate a simple analytic extension of the ensemble-averaged diffusion equation that can account for the effect.

  10. 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

  11. 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.

  12. EMERGENCE OF THE KENNICUTT-SCHMIDT RELATION FROM THE SMALL-SCALE SFR-DENSITY RELATION

    SciTech Connect

    Gnedin, Nickolay Y.; Tasker, Elizabeth J.; Fujimoto, Yusuke

    2014-05-20

    We use simulations of isolated galaxies with a few parsec resolution to explore the connection between the small-scale star formation rate (SFR)-gas density relation and the induced large-scale correlation between the SFR surface density and the surface density of the molecular gas (the Kennicutt-Schmidt relation). We find that, in the simulations, a power-law small-scale ''star formation law'' directly translates into an identical power-law Kennicutt-Schmidt relation. If this conclusion holds in the reality as well, it implies that the observed approximately linear Kennicutt-Schmidt relation must reflect the approximately linear small-scale ''star formation law''.

  13. Weighing the giants- V. Galaxy cluster scaling relations

    NASA Astrophysics Data System (ADS)

    Mantz, Adam B.; Allen, Steven W.; Morris, R. Glenn; von der Linden, Anja; Applegate, Douglas E.; Kelly, Patrick L.; Burke, David L.; Donovan, David; Ebeling, Harald

    2016-12-01

    We present constraints on the scaling relations of galaxy cluster X-ray luminosity, temperature and gas mass (and derived quantities) with mass and redshift, employing masses from robust weak gravitational lensing measurements. These are the first such results obtained from an analysis that simultaneously accounts for selection effects and the underlying mass function, and directly incorporates lensing data to constrain total masses. Our constraints on the scaling relations and their intrinsic scatters are in good agreement with previous studies, and reinforce a picture in which departures from self-similar scaling laws are primarily limited to cluster cores. However, the data are beginning to reveal new features that have implications for cluster astrophysics and provide new tests for hydrodynamical simulations. We find a positive correlation in the intrinsic scatters of luminosity and temperature at fixed mass, which is related to the dynamical state of the clusters. While the evolution of the nominal scaling relations over the redshift range 0.0 < z < 0.5 is consistent with self-similarity, we find tentative evidence that the luminosity and temperature scatters, respectively, decrease and increase with redshift. Physically, this likely related to the development of cool cores and the rate of major mergers. We also examine the scaling relations of redMaPPer richness and Compton Y from Planck. While the richness-mass relation is in excellent agreement with recent work, the measured Y-mass relation departs strongly from that assumed in the Planck cluster cosmology analysis. The latter result is consistent with earlier comparisons of lensing and Planck scaling relation-derived masses.

  14. Development of parallel scales to measure HIV-related stigma.

    PubMed

    Visser, Maretha J; Kershaw, Trace; Makin, Jennifer D; Forsyth, Brian W C

    2008-09-01

    HIV-related stigma is a multidimensional concept which has pervasive effects on the lives of HIV-infected people as well as serious consequences for the management of HIV/AIDS. In this research three parallel stigma scales were developed to assess personal views of stigma, stigma attributed to others, and internalised stigma experienced by HIV-infected individuals. The stigma scales were administered in two samples: a community sample of 1,077 respondents and 317 HIV-infected pregnant women recruited at clinics from the same community in Tshwane (South Africa). A two-factor structure referring to moral judgment and interpersonal distancing was confirmed across scales and sample groups. The internal consistency of the scales was acceptable and evidence of validity is reported. Parallel scales to assess and compare different perspectives of stigma provide opportunities for research aimed at understanding stigma, assessing the consequences or evaluating possible interventions aimed at reducing stigma.

  15. Planck-scale-modified dispersion relations in FRW spacetime

    NASA Astrophysics Data System (ADS)

    Rosati, Giacomo; Amelino-Camelia, Giovanni; Marcianò, Antonino; Matassa, Marco

    2015-12-01

    In recent years, Planck-scale modifications of the dispersion relation have been attracting increasing interest also from the viewpoint of possible applications in astrophysics and cosmology, where spacetime curvature cannot be neglected. Nonetheless, the interplay between Planck-scale effects and spacetime curvature is still poorly understood, particularly in cases where curvature is not constant. These challenges have been so far postponed by relying on an ansatz, first introduced by Jacob and Piran. We propose here a general strategy of analysis of the effects of modifications of the dispersion relation in Friedmann-Robertson-Walker spacetimes, applicable both to cases where the relativistic equivalence of frames is spoiled ("preferred-frame scenarios") and to the alternative possibility of "DSR-relativistic theories," theories that are fully relativistic but with relativistic laws deformed so that the modified dispersion relation is observer independent. We show that the Jacob-Piran ansatz implicitly assumes that spacetime translations are not affected by the Planck scale, while under rather general conditions, the same Planck-scale quantum-spacetime structures producing modifications of the dispersion relation also affect translations. Through the explicit analysis of one of the effects produced by modifications of the dispersion relation, an effect amounting to Planck-scale corrections to travel times, we show that our concerns are not merely conceptual but rather can have significant quantitative implications.

  16. Scale relativity theory and integrative systems biology: 1. Founding principles and scale laws.

    PubMed

    Auffray, Charles; Nottale, Laurent

    2008-05-01

    In these two companion papers, we provide an overview and a brief history of the multiple roots, current developments and recent advances of integrative systems biology and identify multiscale integration as its grand challenge. Then we introduce the fundamental principles and the successive steps that have been followed in the construction of the scale relativity theory, and discuss how scale laws of increasing complexity can be used to model and understand the behaviour of complex biological systems. In scale relativity theory, the geometry of space is considered to be continuous but non-differentiable, therefore fractal (i.e., explicitly scale-dependent). One writes the equations of motion in such a space as geodesics equations, under the constraint of the principle of relativity of all scales in nature. To this purpose, covariant derivatives are constructed that implement the various effects of the non-differentiable and fractal geometry. In this first review paper, the scale laws that describe the new dependence on resolutions of physical quantities are obtained as solutions of differential equations acting in the scale space. This leads to several possible levels of description for these laws, from the simplest scale invariant laws to generalized laws with variable fractal dimensions. Initial applications of these laws to the study of species evolution, embryogenesis and cell confinement are discussed.

  17. Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables

    NASA Astrophysics Data System (ADS)

    Nottale, Laurent; Célérier, Marie-Noëlle

    2013-11-01

    One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.

  18. Emergence of complex and spinor wave functions in scale relativity. I. Nature of scale variables

    SciTech Connect

    Nottale, Laurent; Célérier, Marie-Noëlle

    2013-11-15

    One of the main results of scale relativity as regards the foundation of quantum mechanics is its explanation of the origin of the complex nature of the wave function. The scale relativity theory introduces an explicit dependence of physical quantities on scale variables, founding itself on the theorem according to which a continuous and non-differentiable space-time is fractal (i.e., scale-divergent). In the present paper, the nature of the scale variables and their relations to resolutions and differential elements are specified in the non-relativistic case (fractal space). We show that, owing to the scale-dependence which it induces, non-differentiability involves a fundamental two-valuedness of the mean derivatives. Since, in the scale relativity framework, the wave function is a manifestation of the velocity field of fractal space-time geodesics, the two-valuedness of velocities leads to write them in terms of complex numbers, and yields therefore the complex nature of the wave function, from which the usual expression of the Schrödinger equation can be derived.

  19. Scaling of Quench Front and Entrainment-Related Phenomena

    SciTech Connect

    Aumiller, D. L.; Hourser, R. J.; Holowach, M. J.; Hochreiter, L. E.; Cheung, F-B.

    2002-04-01

    The scaling of thermal hydraulic systems is of great importance in the development of experiments in laboratory-scale test facilities that are used to replicate the response of full-size prototypical designs. One particular phenomenon that is of interest in experimental modeling is the quench front that develops during the reflood phase in a PWR (Pressurized Water Reactor) following a large-break LOCA (Loss of Coolant Accident). The purpose of this study is to develop a scaling methodology such that the prototypical quench front related phenomena can be preserved in a laboratory-scale test facility which may have material, geometrical, fluid, and flow differences as compared to the prototypical case. A mass and energy balance on a Lagrangian quench front control volume along with temporal scaling methods are utilized in developing the quench front scaling groups for a phenomena-specific second-tier scaling analysis. A sample calculation is presented comparing the quench front scaling groups calculated for a prototypical Westinghouse 17 x 17 PWR fuel design and that of the geometry and material configuration used in the FLECHT SEASET series of experiments.

  20. 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

  1. 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

  2. Scaling Relations for Wheeled Locomotion in Granular Media

    NASA Astrophysics Data System (ADS)

    Slonaker, James; Kamrin, Ken

    Vehicular wheel design for use on granular material has not currently been perfected. Resistive Force Theory (RFT) is a reduced-order empirical model for granular drag, which shows promise to help simulate and understand locomotion processes to design more efficient wheels. Here we explore the fundamental scaling relations derived from RFT and their experimental validation. Similar to the non-dimensional scaling relations in fluid mechanics, the relative simplicity of RFT asserts that only one material parameter, the ''grain-structure coefficient'', is required, which reduces the complexity of the non-dimensional groups implied by the system. Therefore, wheels with differing input design parameters like size, mass, shape and even gravity, can be tested and their performance related to each other in predictable ways. We experimentally confirmed these relations by testing with 3D printed wheel geometries in a controlled sand bed.

  3. Relatively scaled ECE temperature profiles of KSTAR plasmas.

    PubMed

    Choi, M J; Yun, G S; Park, H K; Jeon, Y M; Jeong, S H

    2010-10-01

    A scheme to obtain relatively scaled profiles of electron cyclotron emission (ECE) temperature directly from uncalibrated raw radiometer data is proposed and has been tested for the 2009 campaign KSTAR plasmas. The proposed method utilizes a position controlled system to move the plasma adiabatically and compares ECE radiometer channels at the same relative radial positions assuming the profile consistency during the adiabatic change. This scaling method is an alternative solution when an absolute calibration is unreliable or too time consuming. The application to the two dimensional ECE imaging data, wherein calibration is extremely difficult, may also prove to be useful.

  4. Relatively scaled ECE temperature profiles of KSTAR plasmas

    SciTech Connect

    Choi, M. J.; Yun, G. S.; Park, H. K.; Jeon, Y. M.; Jeong, S. H.

    2010-10-15

    A scheme to obtain relatively scaled profiles of electron cyclotron emission (ECE) temperature directly from uncalibrated raw radiometer data is proposed and has been tested for the 2009 campaign KSTAR plasmas. The proposed method utilizes a position controlled system to move the plasma adiabatically and compares ECE radiometer channels at the same relative radial positions assuming the profile consistency during the adiabatic change. This scaling method is an alternative solution when an absolute calibration is unreliable or too time consuming. The application to the two dimensional ECE imaging data, wherein calibration is extremely difficult, may also prove to be useful.

  5. Scaling relations for gaps in fractional quantum Hall states

    NASA Astrophysics Data System (ADS)

    Murthy, Ganpathy; Park, K.; Shankar, R.; Jain, J. K.

    1998-12-01

    The microscopic Hamiltonian approach of Murthy and Shankar, which has recently been used to calculate the transport gaps of quantum Hall states with fractions ν=p/(2ps+1), also implies scaling relations between gaps within a single sequence (fixed s) as well as between gaps of corresponding states in different sequences. This work tests these relations for a system of electrons in the lowest Landau level interacting with a model potential cutoff at high momenta due to sample thickness.

  6. Violence-Related Attitudes and Beliefs: Scale Construction and Psychometrics

    ERIC Educational Resources Information Center

    Brand, Pamela A.; Anastasio, Phyllis A.

    2006-01-01

    The 50-item Violence-Related Attitudes and Beliefs Scale (V-RABS) includes three subscales measuring possible causes of violent behavior (environmental influences, biological influences, and mental illness) and four subscales assessing possible controls of violent behavior (death penalty, punishment, prevention, and catharsis). Each subscale…

  7. 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

  8. Does the Milky Way Obey Spiral Galaxy Scaling Relations?

    NASA Astrophysics Data System (ADS)

    Licquia, Timothy C.; Newman, Jeffrey A.; Bershady, Matthew A.

    2016-12-01

    It is crucial to understand how the Milky Way (MW), the galaxy we can study in the most intimate detail, fits in among other galaxies. Key considerations include the Tully-Fisher relation (TFR)—i.e., the tight correlation between luminosity (L) and rotational velocity (V rot)—and the three-dimensional luminosity-velocity-radius (LVR) scaling relation. Several past studies have characterized the MW as a 1-1.5σ outlier to the TFR. This study re-examines such comparisons using new estimates of MW properties that are robust to many of the systematic uncertainties that have been a problem in the past and are based on assumptions consistent with those used for other spiral galaxies. Comparing to scaling relations derived from modern extragalactic data, we find that our Galaxy’s properties are in excellent agreement with TFRs defined using any Sloan Digital Sky Survey-filter absolute magnitude, stellar mass, or baryonic mass as the L proxy. We next utilize disk scale length (R d) measurements to extend this investigation to the LVR relation. Here we find that our Galaxy lies farther from the relation than ˜90% of other spiral galaxies, yielding ˜9.5σ evidence that it is unusually compact for its L and V rot (based on MW errors alone), a result that holds for all of the L proxies considered. The expected R d for the MW from the LVR relation is ˜5 kpc, nearly twice as large as the observed value, with error estimates placing the two in tension at the ˜1.4σ level. The compact scale length of the Galactic disk could be related to other ways in which the MW has been found to be anomalous.

  9. Lagrangian space consistency relation for large scale structure

    SciTech Connect

    Horn, Bart; Hui, Lam; Xiao, Xiao E-mail: lh399@columbia.edu

    2015-09-01

    Consistency relations, which relate the squeezed limit of an (N+1)-point correlation function to an N-point function, are non-perturbative symmetry statements that hold even if the associated high momentum modes are deep in the nonlinear regime and astrophysically complex. Recently, Kehagias and Riotto and Peloso and Pietroni discovered a consistency relation applicable to large scale structure. We show that this can be recast into a simple physical statement in Lagrangian space: that the squeezed correlation function (suitably normalized) vanishes. This holds regardless of whether the correlation observables are at the same time or not, and regardless of whether multiple-streaming is present. The simplicity of this statement suggests that an analytic understanding of large scale structure in the nonlinear regime may be particularly promising in Lagrangian space.

  10. Time evolution of galaxy scaling relations in cosmological simulations

    NASA Astrophysics Data System (ADS)

    Taylor, Philip; Kobayashi, Chiaki

    2016-12-01

    We predict the evolution of galaxy scaling relationships from cosmological, hydrodynamical simulations, that reproduce the scaling relations of present-day galaxies. Although we do not assume co-evolution between galaxies and black holes a priori, we are able to reproduce the black hole mass-velocity dispersion relation. This relation does not evolve, and black holes actually grow along the relation from significantly less massive seeds than have previously been used. AGN feedback does not very much affect the chemical evolution of our galaxies. In our predictions, the stellar mass-metallicity relation does not change its shape, but the metallicity significantly increases from z ˜ 2 to z ˜ 1, while the gas-phase mass-metallicity relation does change shape, having a steeper slope at higher redshifts (z ≲ 3). Furthermore, AGN feedback is required to reproduce observations of the most massive galaxies at z ≲ 1, specifically their positions on the star formation main sequence and galaxy mass-size relation.

  11. Ontogenetic Scaling of Theoretical Bite Force in Southern Sea Otters (Enhydra lutris nereis).

    PubMed

    Law, Chris J; Young, Colleen; Mehta, Rita S

    2016-01-01

    Sexual dimorphism attributed to niche divergence is often linked to differentiation between the sexes in both dietary resources and characters related to feeding and resource procurement. Although recent studies have indicated that southern sea otters (Enhydra lutris nereis) exhibit differences in dietary preferences as well as sexual dimorphism in skull size and shape, whether these intersexual differences translate to differentiation in feeding performances between the sexes remains to be investigated. To test the hypothesis that scaling patterns of bite force, a metric of feeding performance, differ between the sexes, we calculated theoretical bite forces for 55 naturally deceased male and female southern sea otters spanning the size ranges encountered over ontogeny. We then used standardized major axis regressions to simultaneously determine the scaling patterns of theoretical bite forces and skull components across ontogeny and assess whether these scaling patterns differed between the sexes. We found that positive allometric increases in theoretical bite force resulted from positive allometric increases in physiological cross-sectional area for the major jaw adductor muscle and mechanical advantage. Closer examination revealed that allometric increases in temporalis muscle mass and relative allometric decreases in out-lever lengths are driving these patterns. In our analysis of sexual dimorphism, we found that scaling patterns of theoretical bite force and morphological traits do not differ between the sexes. However, adult sea otters differed in their absolute bite forces, revealing that adult males exhibited greater bite forces as a result of their larger sizes. We found intersexual differences in biting ability that provide some support for the niche divergence hypothesis. Continued work in this field may link intersexual differences in feeding functional morphology with foraging ecology to show how niche divergence has the potential to reinforce sexual

  12. Implicit Priors in Galaxy Cluster Mass and Scaling Relation Determinations

    NASA Technical Reports Server (NTRS)

    Mantz, A.; Allen, S. W.

    2011-01-01

    Deriving the total masses of galaxy clusters from observations of the intracluster medium (ICM) generally requires some prior information, in addition to the assumptions of hydrostatic equilibrium and spherical symmetry. Often, this information takes the form of particular parametrized functions used to describe the cluster gas density and temperature profiles. In this paper, we investigate the implicit priors on hydrostatic masses that result from this fully parametric approach, and the implications of such priors for scaling relations formed from those masses. We show that the application of such fully parametric models of the ICM naturally imposes a prior on the slopes of the derived scaling relations, favoring the self-similar model, and argue that this prior may be influential in practice. In contrast, this bias does not exist for techniques which adopt an explicit prior on the form of the mass profile but describe the ICM non-parametrically. Constraints on the slope of the cluster mass-temperature relation in the literature show a separation based the approach employed, with the results from fully parametric ICM modeling clustering nearer the self-similar value. Given that a primary goal of scaling relation analyses is to test the self-similar model, the application of methods subject to strong, implicit priors should be avoided. Alternative methods and best practices are discussed.

  13. 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.

  14. 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

  15. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  16. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-06-01

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. In this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. The reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  17. Scaling Relations for Intercalation Induced Damage in Electrodes

    DOE PAGES

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; ...

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based onmore » a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.« less

  18. Large scale obscuration and related climate effects open literature bibliography

    SciTech Connect

    Russell, N.A.; Geitgey, J.; Behl, Y.K.; Zak, B.D.

    1994-05-01

    Large scale obscuration and related climate effects of nuclear detonations first became a matter of concern in connection with the so-called ``Nuclear Winter Controversy`` in the early 1980`s. Since then, the world has changed. Nevertheless, concern remains about the atmospheric effects of nuclear detonations, but the source of concern has shifted. Now it focuses less on global, and more on regional effects and their resulting impacts on the performance of electro-optical and other defense-related systems. This bibliography reflects the modified interest.

  19. 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.

  20. Scaling, crumpled wires, and genome packing in virions

    NASA Astrophysics Data System (ADS)

    de Holanda, V. H.; Gomes, M. A. F.

    2016-12-01

    The packing of a genome in virions is a topic of intense current interest in biology and biological physics. The area is dominated by allometric scaling relations that connect, e.g., the length of the encapsulated genome and the size of the corresponding virion capsid. Here we report scaling laws obtained from extensive experiments of packing of a macroscopic wire within rigid three-dimensional spherical and nonspherical cavities that can shed light on the details of the genome packing in virions. We show that these results obtained with crumpled wires are comparable to those from a large compilation of biological data from several classes of virions.

  1. Scaling relations in the diffusive infiltration in fractals

    NASA Astrophysics Data System (ADS)

    Aarão Reis, F. D. A.

    2016-11-01

    In a recent work on fluid infiltration in a Hele-Shaw cell with the pore-block geometry of Sierpinski carpets (SCs), the area filled by the invading fluid was shown to scale as F ˜tn , with n <1 /2 , thus providing a macroscopic realization of anomalous diffusion [Filipovitch et al., Water Resour. Res. 52, 5167 (2016), 10.1002/2016WR018667]. The results agree with simulations of a diffusion equation with constant pressure at one of the borders of those fractals, but the exponent n is very different from the anomalous exponent ν =1 /DW of single-particle diffusion in the same fractals (DW is the random-walk dimension). Here we use a scaling approach to show that those exponents are related as n =ν (DF-DB) , where DF and DB are the fractal dimensions of the bulk and the border from which diffusing particles come, respectively. This relation is supported by accurate numerical estimates in two SCs and in two generalized Menger sponges (MSs), in which we performed simulations of single-particle random walks (RWs) with a rigid impermeable border and of a diffusive infiltration model in which that border is permanently filled with diffusing particles. This study includes one MS whose external border is also fractal. The exponent relation is also consistent with the recent simulational and experimental results on fluid infiltration in SCs, and explains the approximate quadratic dependence of n on DF in these fractals. We also show that the mean-square displacement of single-particle RWs has log-periodic oscillations, whose periods are similar for fractals with the same scaling factor in the generator (even with different embedding dimensions), which is consistent with the discrete scale invariance scenario. The roughness of a diffusion front defined in the infiltration problem also shows this type of oscillation, which is enhanced in fractals with narrow channels between large lacunas.

  2. Scaling Relations of Galactic Winds with Star Formation Rate

    NASA Astrophysics Data System (ADS)

    Tanner, Ryan; Cecil, Gerald; Heitsch, Fabian

    2017-01-01

    The galactic scale outflows generated by nuclear starbursts consist of a multiphase medium where each phase has a distinct velocity depending on the characteristics of the starburst. Using synthetic absorption lines generated from 3D hydrodynamical simulations we probe the outflow velocity of the hot, warm, and neutral gas entrained in a galactic wind. By varying the star formation rate (SFR) in our simulations, we find no correlation between the outflow velocity of the hot gas with the SFR, but we do find a correlation between the outflow velocity of both warm and neutral gas with the SFR. The scaling relation between outflow velocity and SFR only holds for low SFR until the scaling relation abruptly flattens at a SFR determined by the mass loading of the starburst. The outflow velocity of the hot gas only depends on the mass loading of the starburst and not the SFR. For low SFRs the difference between the velocity of cold gas, as measured by absorption lines of neutral or low ionized gas, may be 5-7 times lower than the velocity of the hot, highly ionized gas. The difference in velocity between the cold and hot gas for higher SFRs depends on the mass loading factor of the starburst. Thus the measured velocities of neutral or low ionized gas cannot be used to estimate the outflow velocity of the hot gas without determining the mass loading of the starburst.

  3. Influence of mechanical stratigraphy and kinematics on fault scaling relations

    NASA Astrophysics Data System (ADS)

    Gross, Michael R.; G´rrez-Alonso, Gabriel; Bai, Taixu; Wacker, Michael A.; Collinsworth, Kevin B.; Behl, Richard J.

    1997-02-01

    In order to document effects of mechanical anisotropy, fault geometry, and structural style on displacement-length ( D-L) scaling relations, we investigated fault dimensions in the lithologically heterogeneous Monterey Formation exposed along Arroyo Burro Beach, California. The faults, which range in length from several centimeters to several meters, group into two populations: small faults confined to individual mudstone beds, and larger faults that displace multiple beds and often merge into bedding plane detachments. Whereas a linear correlation exists between displacement and length for small faults, displacement across large faults is independent of length. We attribute this deviation from scale-invariance to a combination of geologic factors that influence fault growth once faults extend beyond the confines of mudstone beds. Propagation of large faults across higher moduli opal-CT porcellanite leads to a reduction in DL, as does the development of drag folds. Further scatter in DL occurs when fault tips splay as they approach detachments. Large faults eventually merge into bedding plane detachments, which originally formed due to flexural slip folding. Extremely high DL ratios are recorded for these merged faults as they accommodate block rotation within a simple shear zone. Thus, both mechanical stratigraphy and the temporal evolution of fault systems can lead to a breakdown in fault scaling relations thought to characterize isolated fault growth in a homogeneous medium.

  4. Scaling Relations for Adsorption Energies on Doped Molybdenum Phosphide Surfaces

    DOE PAGES

    Fields, Meredith; Tsai, Charlie; Chen, Leanne D.; ...

    2017-03-10

    Molybdenum phosphide (MoP), a well-documented catalyst for applications ranging from hydrotreating reactions to electrochemical hydrogen evolution, has yet to be mapped from a more fundamental perspective, particularly in the context of transition-metal scaling relations. In this work, we use periodic density functional theory to extend linear scaling arguments to doped MoP surfaces and understand the behavior of the phosphorus active site. The derived linear relationships for hydrogenated C, N, and O species on a variety of doped surfaces suggest that phosphorus experiences a shift in preferred bond order depending on the degree of hydrogen substitution on the adsorbate molecule. Thismore » shift in phosphorus hybridization, dependent on the bond order of the adsorbate to the surface, can result in selective bond weakening or strengthening of chemically similar species. As a result, we discuss how this behavior deviates from transition-metal, sulfide, carbide, and nitride scaling relations, and we discuss potential applications in the context of electrochemical reduction reactions.« less

  5. 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.

  6. On the Use of Scaling Relations for the Tolman Test

    NASA Astrophysics Data System (ADS)

    Moles, Mariano; Campos, Ana; Kjærgaard, Per; Fasano, Giovanni; Bettoni, Daniela

    1998-03-01

    The use of relations between structural parameters of early-type galaxies to perform the Tolman test for the expansion of the universe is reconsidered. Scaling relations such as the fundamental plane or the Kormendy relation require the transformation from angular to metric sizes, to compare the relation at different z-values. This transformation depends on the assumed world model: galaxies of a given angular size, at a given z, are larger (in units of kiloparsecs) in a nonexpanding universe than in an expanding one. Furthermore, the luminosities of galaxies are expected to evolve with z in an expanding model. These effects are shown to conspire to reduce the difference between the predicted surface brightness (SB) change with redshift in the expanding and nonexpanding cases. We have considered expanding models with passive luminosity evolution. We find that their predictions for the visible photometric bands are very similar to those of the static model until z~1, and therefore the test cannot distinguish between the two world models. Recent good-quality data on the Kormendy relation and the fundamental plane at intermediate redshifts are consistent with the predictions from both models. In the K band, where the expected (model) luminosity evolutionary corrections are smaller, the differences between the expanding and static models amount to ~0.4 (0.8) mag at z=0.4 (1). It is shown that, owing to that small difference between the predictions in the covered z-range, and to the paucity and uncertainties of the relevant SB photometry, the existing K-band data are not adequate to distinguish between the different world metrics and cannot yet be used to discard the static case. It is pointed out that the scaling relations could still be used to rule out the nonevolving case if it could be shown that the coefficients change with the redshift.

  7. Examining Similarity Structure: Multidimensional Scaling and Related Approaches in Neuroimaging

    PubMed Central

    Shinkareva, Svetlana V.; Wedell, Douglas H.

    2013-01-01

    This paper covers similarity analyses, a subset of multivariate pattern analysis techniques that are based on similarity spaces defined by multivariate patterns. These techniques offer several advantages and complement other methods for brain data analyses, as they allow for comparison of representational structure across individuals, brain regions, and data acquisition methods. Particular attention is paid to multidimensional scaling and related approaches that yield spatial representations or provide methods for characterizing individual differences. We highlight unique contributions of these methods by reviewing recent applications to functional magnetic resonance imaging data and emphasize areas of caution in applying and interpreting similarity analysis methods. PMID:23662162

  8. 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

  9. Scaling relations in the diffusive infiltration in fractals.

    PubMed

    Aarão Reis, F D A

    2016-11-01

    In a recent work on fluid infiltration in a Hele-Shaw cell with the pore-block geometry of Sierpinski carpets (SCs), the area filled by the invading fluid was shown to scale as F∼t^{n}, with n<1/2, thus providing a macroscopic realization of anomalous diffusion [Filipovitch et al., Water Resour. Res. 52, 5167 (2016)WRERAQ0043-139710.1002/2016WR018667]. The results agree with simulations of a diffusion equation with constant pressure at one of the borders of those fractals, but the exponent n is very different from the anomalous exponent ν=1/D_{W} of single-particle diffusion in the same fractals (D_{W} is the random-walk dimension). Here we use a scaling approach to show that those exponents are related as n=ν(D_{F}-D_{B}), where D_{F} and D_{B} are the fractal dimensions of the bulk and the border from which diffusing particles come, respectively. This relation is supported by accurate numerical estimates in two SCs and in two generalized Menger sponges (MSs), in which we performed simulations of single-particle random walks (RWs) with a rigid impermeable border and of a diffusive infiltration model in which that border is permanently filled with diffusing particles. This study includes one MS whose external border is also fractal. The exponent relation is also consistent with the recent simulational and experimental results on fluid infiltration in SCs, and explains the approximate quadratic dependence of n on D_{F} in these fractals. We also show that the mean-square displacement of single-particle RWs has log-periodic oscillations, whose periods are similar for fractals with the same scaling factor in the generator (even with different embedding dimensions), which is consistent with the discrete scale invariance scenario. The roughness of a diffusion front defined in the infiltration problem also shows this type of oscillation, which is enhanced in fractals with narrow channels between large lacunas.

  10. New scaling relation for information transfer in biological networks

    PubMed Central

    Kim, Hyunju; Davies, Paul; Walker, Sara Imari

    2015-01-01

    We quantify characteristics of the informational architecture of two representative biological networks: the Boolean network model for the cell-cycle regulatory network of the fission yeast Schizosaccharomyces pombe (Davidich et al. 2008 PLoS ONE 3, e1672 (doi:10.1371/journal.pone.0001672)) and that of the budding yeast Saccharomyces cerevisiae (Li et al. 2004 Proc. Natl Acad. Sci. USA 101, 4781–4786 (doi:10.1073/pnas.0305937101)). We compare our results for these biological networks with the same analysis performed on ensembles of two different types of random networks: Erdös–Rényi and scale-free. We show that both biological networks share features in common that are not shared by either random network ensemble. In particular, the biological networks in our study process more information than the random networks on average. Both biological networks also exhibit a scaling relation in information transferred between nodes that distinguishes them from random, where the biological networks stand out as distinct even when compared with random networks that share important topological properties, such as degree distribution, with the biological network. We show that the most biologically distinct regime of this scaling relation is associated with a subset of control nodes that regulate the dynamics and function of each respective biological network. Information processing in biological networks is therefore interpreted as an emergent property of topology (causal structure) and dynamics (function). Our results demonstrate quantitatively how the informational architecture of biologically evolved networks can distinguish them from other classes of network architecture that do not share the same informational properties. PMID:26701883

  11. Scaling laws of coronary circulation in health and disease.

    PubMed

    Huo, Yunlong; Kassab, Ghassan S

    2016-08-16

    The heterogeneity and complexity of coronary vasculature (structure) and myocardial flow (function) have fractal-like characteristics and can be described by scaling laws with remarkable simplicity. In contrast with allometric (interspecific) scaling law, intraspecific scaling laws describe the design rules of vascular trees within a species. This paper provides an overview of intraspecific scaling laws of vascular trees and the physiological and clinical implications thereof. The significance and shortcomings of these scaling laws are discussed in relation to diffuse coronary artery disease, Glagov's positive remodeling in early stages of coronary atherosclerosis, treatment guidelines of complex bifurcation lesions, and for estimation of outlet resistance values for computation of blood flow in epicardial coronary arteries. Finally, we summarize the highlights of scaling relations and suggest some future directions.

  12. 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.

  13. EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE

    SciTech Connect

    Laura J. Pyrak-Nolte; Nicholas J. Giordano; David D. Nolte

    2004-03-01

    The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements of interfacial area per volume. This project on the experimental investigation of relative permeability upscaling has produced a unique combination of three quite different technical approaches to the upscaling problem of obtaining pore-related microscopic properties and using them to predict macroscopic behavior. Several important ''firsts'' have been achieved during the course of the project. (1) Optical coherence imaging, a laser-based ranging and imaging technique, has produced the first images of grain and pore structure up to 1 mm beneath the surface of the sandstone and in a laboratory borehole. (2) Woods metal injection has connected for the first time microscopic pore-scale geometric measurements with macroscopic saturation in real sandstone cores. (3) The micro-model technique has produced the first invertible relationship between saturation and capillary pressure--showing that interfacial area per volume (IAV) provides the linking parameter. IAV is a key element in upscaling theories, so this experimental finding may represent the most important result of this project, with wide ramifications for predictions of fluid behavior in porous media.

  14. Scaling Relation in Two Situations of Extreme Mergers

    NASA Astrophysics Data System (ADS)

    Rasia, E.; Mazzotta, P.; Evrard, A.; Markevitch, M.; Dolag, K.; Meneghetti, M.

    2011-03-01

    Clusters of galaxies are known to be dynamically active systems, yet X-ray studies of the low-redshift population exhibit tight scaling laws. In this work, we extend previous studies of this apparent paradox using numerical simulations of two extreme merger cases, one is a high Mach number (above 2.5) satellite merger similar to the "bullet cluster" and the other is a merger of nearly equal-mass progenitors. Creating X-ray images densely sampled in time, we construct T X, M gas, and Y X measures within R 500 and compare to the calibrations of Kravtsov et al. We find that these extreme merger cases respect the scaling relations, for both intrinsic measures and for measures derived from appropriately masked, synthetic Chandra X-ray images. The masking procedure plays a critical role in the X-ray temperature calculation, while it is irrelevant in the X-ray gas mass derivation. Miscentering up to 100 kpc does not influence the result. The observationally determined radius R 500 might conduce to systematic shifts in M gas and Y X, which increases the total mass scatter.

  15. Scaling Aspects of Lymphocyte Trafficking

    PubMed Central

    Perelson, Alan S.; Wiegel, Frederik W.

    2010-01-01

    We consider the long lived pool of B and T cells that recirculate through blood, tissues and the lymphatic system of an animal with body mass M. We derive scaling rules (allometric relations) for: (1) the rate of production of mature lymphocytes; (2) the accumulation of lymphocytes in the tissues; (3) the flux of lymphocytes through the lymphatic system; (4) the number of lymph nodes, (5) the number of lymphocytes per clone within a lymph node, and (6) the total number of lymphocytes within a lymph node. Mass-dependent aspects of immune learning and of the immunological self are shown to be not very significant. Our treatment is somewhat heuristic and aims at a combination of immunological data with recent progress in biological scaling. PMID:19084024

  16. Single-field consistency relations of large scale structure

    SciTech Connect

    Creminelli, Paolo; Noreña, Jorge; Simonović, Marko; Vernizzi, Filippo E-mail: jorge.norena@icc.ub.edu E-mail: filippo.vernizzi@cea.fr

    2013-12-01

    We derive consistency relations for the late universe (CDM and ΛCDM): relations between an n-point function of the density contrast δ and an (n+1)-point function in the limit in which one of the (n+1) momenta becomes much smaller than the others. These are based on the observation that a long mode, in single-field models of inflation, reduces to a diffeomorphism since its freezing during inflation all the way until the late universe, even when the long mode is inside the horizon (but out of the sound horizon). These results are derived in Newtonian gauge, at first and second order in the small momentum q of the long mode and they are valid non-perturbatively in the short-scale δ. In the non-relativistic limit our results match with [1]. These relations are a consequence of diffeomorphism invariance; they are not satisfied in the presence of extra degrees of freedom during inflation or violation of the Equivalence Principle (extra forces) in the late universe.

  17. EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE

    SciTech Connect

    JiangTao Cheng; Ping Yu; William Headley; Nicholas Giordao; Mirela Mustata; Daiquan Chen; Nathan Cooper; David D. Nolte; Laura J. Pyrak-Nolte

    2001-12-01

    The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements of interfacial area per volume. During this reporting period, we have shown experimentally and theoretically that the optical coherence imaging system is optimized for sandstone. The measurement of interfacial area per volume (IAV), capillary pressure and saturation in two dimensional micro-models structures that are statistically similar to real porous media has shown the existence of a unique relationship among these hydraulic parameters. The measurement of interfacial area per volume on a three-dimensional natural sample, i.e., sandstone, has the same length-scale as the values of IAV determined for the two-dimensional micro-models.

  18. Intermolecular forces and scaling relations between heterogeneous macromolecular surfaces

    NASA Astrophysics Data System (ADS)

    Rosenberg, Kenneth J.

    Most theories regarding the behavior of intermolecular forces assume perfectly smooth surfaces with well-defined chemical and material properties. In this thesis, three separate systems are studied to explore the accuracy of this assumption in very different situations. In the first system, the effects of milli-molar amounts of dissolved gas (the amount typically present in normal atmospheric conditions) have been studied at a pristine oil/water interface. It was found that the removal of the dissolved gas significantly increased the lifetime of the oil droplets, effectively reducing the long-range hydrophobic attractive force present under standard conditions. In the second system, the effect of varying normal and lateral roughness of solid surfaces in understanding the long-range steric forces and shorter-range adhesive (van der Waals) forces are studied. Various techniques to reproducibly control and vary the roughness were developed for a number of different types of polymeric surfaces. A strong correlation between the roughness and the repulsive steric force was observed for randomly rough surfaces. Similar scaling relations between the roughness and the magnitude of the adhesive force were measured. Friction measurements between these surfaces show that even a few nanometers of roughness significantly reduces the critical shear stress required to initiate sliding. However, the coefficient of friction was relatively unaffected by the range of roughness considered, in agreement with the macroscopic Amontons' law. The third and final system dealt with the properties of adsorbed layers of polyampholytes (containing both positively and negatively charged groups), as opposed to the more common classes of neutral polymers or polyelectrolytes. These measurements took advantage of a naturally occurring family of proteins (a class of polyampholytes), known as tau, which exist in six different well-defined lengths and charge densities. Force measurements were made with

  19. 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.

  20. 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.

  1. 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...

  2. Large Scale Obscuration and Related Climate Effects Workshop: Proceedings

    SciTech Connect

    Zak, B.D.; Russell, N.A.; Church, H.W.; Einfeld, W.; Yoon, D.; Behl, Y.K.

    1994-05-01

    A Workshop on Large Scale Obsurcation and Related Climate Effects was held 29--31 January, 1992, in Albuquerque, New Mexico. The objectives of the workshop were: to determine through the use of expert judgement the current state of understanding of regional and global obscuration and related climate effects associated with nuclear weapons detonations; to estimate how large the uncertainties are in the parameters associated with these phenomena (given specific scenarios); to evaluate the impact of these uncertainties on obscuration predictions; and to develop an approach for the prioritization of further work on newly-available data sets to reduce the uncertainties. The workshop consisted of formal presentations by the 35 participants, and subsequent topical working sessions on: the source term; aerosol optical properties; atmospheric processes; and electro-optical systems performance and climatic impacts. Summaries of the conclusions reached in the working sessions are presented in the body of the report. Copies of the transparencies shown as part of each formal presentation are contained in the appendices (microfiche).

  3. Size and scaling in human evolution.

    PubMed

    Pilbeam, D; Gould, S J

    1974-12-06

    Our general conclusion is simply stated: many lineages display phyletic size increase; allometric changes almost always accompany increase in body size. We cannot judge adaptation until we separate such changes into those required by increasing size and those serving as special adaptations to changing environments. In our view, the three australopithecines are, in a number of features, scaled variants of the "same" animal. In these characters, A. africanus is no more "advanced" than the larger, more robust forms. The one early hominid to show a significant departure from this adaptive pattern toward later hominids-cranially, dentally, and postcranially-is H. habilis from East Africa. The australopithecines, one of which was probably a precursor of the Homolineage, were apparently a successful group of basically vegetarian hominids, more advanced behaviorally than apes (87), but not hunter-gatherers. The fossil hominids of Africa fall into two major groupings. One probable lineage, the australopithecines, apparently became extinct without issue; the other evolved to modern man. Both groups displayed steady increase in body size. We consider quantitatively two key characters of the hominid skull: cranial capacity and cheek tooth size. The variables are allometrically related to body size in both lineages. In australopithecines, the manner of relative growth neatly meets the predictions for functional equivalence over a wide range of sizes (negative allometry of cranial capacity with a slope against body weight of 0.2 to 0.4 and positive allometry of postcanine area with a slope near 0.75). In the A. africanus to H. sapiens lineage, cranial capacity increases with positive allometry (slope 1.73) while cheek teeth decrease absolutely (slope - 0.725). Clearly, these are special adaptations unrelated to the physical requirements of increasing body size. We examined qualitatively other features, which also seem to vary allometrically. Of course, many characters should be

  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. Work related injuries in small scale commercial fishing

    PubMed Central

    Marshall, S; Kucera, K; Loomis, D; McDonald, M; Lipscomb, H

    2004-01-01

    Objective: To describe the epidemiology of work related injury in a group of small scale, independent commercial fishers. Design: Cross sectional survey (baseline instrument of a prospective cohort study). Setting and subjects: Commercial fishers in eastern North Carolina. Results: A cohort of 219 commercial fishers was established and 215 subjects completed an injury questionnaire. The main types of fishing conducted by the cohort were finfishing (159/215) and crabbing (154/215). Of the 215 fishers, 83 reported that they had suffered an injury event in the previous 12 months, a retrospective recall incidence proportion of 38.6 per 100 workers (95% confidence interval 32.1 to 45.1). The 83 injury events resulted in 94 injuries; 47% were penetrating wounds and 24% were strains/sprains. Half of injuries were to the hand/wrist/digits and 13% were to the back. Of the penetrating wounds, 87% were to the hand/wrist/digits, 32% became infected, and 80% were caused by contact with finfish, shellfish, or other marine animal. Of the strains/sprains, 48% were to the back and 26% were to the shoulder. Seventy percent of strains/sprains were caused by moving heavy objects, mainly either while hauling in nets, pots, or lines or loading/unloading the boat. Conclusion: In this group of small scale, independent fishers, the most common reported injuries were penetrating wounds to the hand/wrist/digits from marine animals and strains/sprains to the back while moving heavy objects. PMID:15314048

  6. Theoretical z -pinch scaling relations for thermonuclear-fusion experiments.

    PubMed

    Stygar, W A; Cuneo, M E; Vesey, R A; Ives, H C; Mazarakis, M G; Chandler, G A; Fehl, D L; Leeper, R J; Matzen, M K; McDaniel, D H; McGurn, J S; McKenney, J L; Muron, D J; Olson, C L; Porter, J L; Ramirez, J J; Seamen, J F; Speas, C S; Spielman, R B; Struve, K W; Torres, J A; Waisman, E M; Wagoner, T C; Gilliland, T L

    2005-08-01

    We have developed wire-array z -pinch scaling relations for plasma-physics and inertial-confinement-fusion (ICF) experiments. The relations can be applied to the design of z -pinch accelerators for high-fusion-yield (approximately 0.4 GJ/shot) and inertial-fusion-energy (approximately 3 GJ/shot) research. We find that (delta(a)/delta(RT)) proportional (m/l)1/4 (Rgamma)(-1/2), where delta(a) is the imploding-sheath thickness of a wire-ablation-dominated pinch, delta(RT) is the sheath thickness of a Rayleigh-Taylor-dominated pinch, m is the total wire-array mass, l is the axial length of the array, R is the initial array radius, and gamma is a dimensionless functional of the shape of the current pulse that drives the pinch implosion. When the product Rgamma is held constant the sheath thickness is, at sufficiently large values of m/l, determined primarily by wire ablation. For an ablation-dominated pinch, we estimate that the peak radiated x-ray power P(r) proportional (I/tau(i))(3/2)Rlphigamma, where I is the peak pinch current, tau(i) is the pinch implosion time, and phi is a dimensionless functional of the current-pulse shape. This scaling relation is consistent with experiment when 13 MA < or = I < or = 20 MA, 93 ns < or = tau(i) < or = 169 ns, 10 mm < or = R < or = 20 mm, 10 mm < or = l < or = 20 mm, and 2.0 mg/cm < or = m/l < or = 7.3 mg/cm. Assuming an ablation-dominated pinch and that Rlphigamma is held constant, we find that the x-ray-power efficiency eta(x) congruent to P(r)/P(a) of a coupled pinch-accelerator system is proportional to (tau(i)P(r)(7/9 ))(-1), where P(a) is the peak accelerator power. The pinch current and accelerator power required to achieve a given value of P(r) are proportional to tau(i), and the requisite accelerator energy E(a) is proportional to tau2(i). These results suggest that the performance of an ablation-dominated pinch, and the efficiency of a coupled pinch-accelerator system, can be improved substantially by decreasing the

  7. Kelvin Absolute Temperature Scale Identified as Length Scale and Related to de Broglie Thermal Wavelength

    NASA Astrophysics Data System (ADS)

    Sohrab, Siavash

    Thermodynamic equilibrium between matter and radiation leads to de Broglie wavelength λdβ = h /mβvrβ and frequency νdβ = k /mβvrβ of matter waves and stochastic definitions of Planck h =hk =mk <λrk > c and Boltzmann k =kk =mk <νrk > c constants, λrkνrk = c , that respectively relate to spatial (λ) and temporal (ν) aspects of vacuum fluctuations. Photon massmk =√{ hk /c3 } , amu =√{ hkc } = 1 /No , and universal gas constant Ro =No k =√{ k / hc } result in internal Uk = Nhνrk = Nmkc2 = 3 Nmkvmpk2 = 3 NkT and potential pV = uN\\vcirc / 3 = N\\ucirc / 3 = NkT energy of photon gas in Casimir vacuum such that H = TS = 4 NkT . Therefore, Kelvin absolute thermodynamic temperature scale [degree K] is identified as length scale [meter] and related to most probable wavelength and de Broglie thermal wavelength as Tβ =λmpβ =λdβ / 3 . Parallel to Wien displacement law obtained from Planck distribution, the displacement law λwS T =c2 /√{ 3} is obtained from Maxwell -Boltzmann distribution of speed of ``photon clusters''. The propagation speeds of sound waves in ideal gas versus light waves in photon gas are described in terms of vrβ in harmony with perceptions of Huygens. Newton formula for speed of long waves in canals √{ p / ρ } is modified to √{ gh } =√{ γp / ρ } in accordance with adiabatic theory of Laplace.

  8. Scaling Relations Between Warm Galactic Outflows and Their Host Galaxies

    NASA Astrophysics Data System (ADS)

    Chisholm, John; Tremonti, Christy A.; Leitherer, Claus; Chen, Yanmei; Wofford, Aida; Lundgren, Britt

    2015-10-01

    We report on a sample of 48 nearby, star-forming galaxies observed with the Cosmic Origin Spectrograph on the Hubble Space Telescope. We measure the kinematics of warm gas in galactic outflows using a combination of four Si ii absorption lines. We use multi-wavelength ancillary data to estimate stellar masses (M*), star formation rates (SFR), circular velocities (vcirc), and morphologies. The galaxies cover four orders of magnitude in M* and SFR, and sample a wide range of morphologies from starbursting mergers to normal star-forming galaxies. We derive 3.0-3.5σ relations between outflow velocity and SFR, M*, and vcirc. The outflow velocities scale as SFR0.08-0.22, {M}*0.12-0.20 and {v}{circ}0.44-0.87, with the range depending on whether we use a maximum or a central velocity to quantify the outflow velocity. After accounting for their increased SFR, mergers drive 32% faster outflows than non-merging galaxies, with all of the highest velocity outflows arising from mergers. Low-mass galaxies (log(M*/ M⊙) < 10.5) lose some low-ionization gas through galactic outflows, while more massive galaxies retain all of their low-ionization gas, unless they undergo a merger.

  9. Following Black Hole Scaling Relations through Gas-rich Mergers

    NASA Astrophysics Data System (ADS)

    Medling, Anne M.; U, Vivian; Max, Claire E.; Sanders, David B.; Armus, Lee; Holden, Bradford; Mieda, Etsuko; Wright, Shelley A.; Larkin, James E.

    2015-04-01

    We present black hole mass measurements from kinematic modeling of high-spatial resolution integral field spectroscopy of the inner regions of nine nearby (ultra-)luminous infrared galaxies in a variety of merger stages. These observations were taken with OSIRIS and laser guide star adaptive optics on the Keck I and Keck II telescopes, and reveal gas and stellar kinematics inside the spheres of influence of these supermassive black holes. We find that this sample of black holes are overmassive (˜107-9 {{M}}) compared to the expected values based on black hole scaling relations, and suggest that the major epoch of black hole growth occurs in early stages of a merger, as opposed to during a final episode of quasar-mode feedback. The black hole masses presented are the dynamical masses enclosed in ˜25 pc, and could include gas which is gravitationally bound to the black hole but has not yet lost sufficient angular momentum to be accreted. If present, this gas could in principle eventually fuel active galactic nucleus feedback or be itself blown out from the system.

  10. NON-GAUSSIAN SCATTER IN CLUSTER SCALING RELATIONS

    SciTech Connect

    Shaw, Laurie D.; Holder, Gilbert P.; Dudley, Jonathan

    2010-06-10

    We investigate the impact of non-Gaussian scatter in the cluster mass-observable scaling relation on the mass and redshift distribution of clusters detected by wide area surveys. We parameterize non-Gaussian scatter by incorporating the third and fourth moments (skewness and kurtosis) into the distribution P(M {sub obs}|M). We demonstrate that the effect of the higher order moments becomes important when the product of the standard deviation of P(M {sub obs}|M) and the slope of the mass function is greater than unity. For high scatter mass indicators it is therefore necessary for the survey, limiting mass threshold to be less than 10{sup 14} h {sup -1} M {sub sun}, to prevent the skewness from having a significant impact on the observed number counts, particularly at high redshift. We also show that an unknown level of non-Gaussianity in the scatter is equivalent to an additional uncertainty on the variance in P(M {sub obs}|M) and thus may limit the constraints that can be placed on {sigma}{sub 8} and the dark energy equation of state parameter w.

  11. ISM and dynamical scaling relations in the local Universe

    NASA Astrophysics Data System (ADS)

    Cortese, L.

    2016-06-01

    In the last decade we have seen a tremendous progress in our understanding of the life cycle of galaxies. Particularly powerful has been the synergy between representative surveys of cold gas, dust and metals and improved theoretical models able to follow the evolution of the different phases of the ISM in a self-consistent way. At the same time, the advent of optical integral field spectroscopic surveys is finally allowing us to quantify how the kinematical properties of gas and stars vary across the Hubble sequence. In this talk, I will review recent observational work aimed at providing a local benchmark for the study of the star formation cycle in galaxies and dynamical scaling relations in galaxies. By combining observations obtained as part the Herschel Reference Survey, the GALEX Arecibo SDSS survey, the ALFALFA survey and the SAMI Galaxy Survey, I will discuss what nearby galaxies can teach us about the interplay between kinematics, star formation, chemical enrichment and environmental effects in our neighbourhoods.

  12. Intra- and Interspecific Interactions as Proximate Determinants of Sexual Dimorphism and Allometric Trajectories in the Bottlenose Dolphin Tursiops truncatus (Cetacea, Odontoceti, Delphinidae)

    PubMed Central

    2016-01-01

    Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations. Landmark configurations were transformed, standardized and superimposed through a Generalized Procrustes Analysis. Size and shape differences between adult males and females were respectively evaluated through ANOVA on centroid size, Procrustes ANOVA on Procrustes distances, and MANOVA on Procrustes coordinates. Ontogenetic allometry was investigated by multivariate regression of shape coordinates on centroid size in the largest homogenous sample from the North Sea. Results evidenced sexual dimorphic asymmetric traits only detected in the adults of the North Sea bottlenose dolphins living in monospecific associations, with females bearing a marked incision of the cavity hosting the left tympanic bulla. These differences were related to a more refined echolocalization system that likely enhances the exploitation of local resources by philopatric females. Distinct shape in immature versus mature stages and asymmetric changes in postnatal allometry of dorsal and occipital traits, suggest that differences between males and females are established early during growth. Allometric growth trajectories differed between males and females for the ventral view of the skull. Allometric trajectories differed among projections of skull and mandible, and were related to dietary

  13. Intra- and Interspecific Interactions as Proximate Determinants of Sexual Dimorphism and Allometric Trajectories in the Bottlenose Dolphin Tursiops truncatus (Cetacea, Odontoceti, Delphinidae).

    PubMed

    de Francesco, Maria Carla; Loy, Anna

    2016-01-01

    Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations. Landmark configurations were transformed, standardized and superimposed through a Generalized Procrustes Analysis. Size and shape differences between adult males and females were respectively evaluated through ANOVA on centroid size, Procrustes ANOVA on Procrustes distances, and MANOVA on Procrustes coordinates. Ontogenetic allometry was investigated by multivariate regression of shape coordinates on centroid size in the largest homogenous sample from the North Sea. Results evidenced sexual dimorphic asymmetric traits only detected in the adults of the North Sea bottlenose dolphins living in monospecific associations, with females bearing a marked incision of the cavity hosting the left tympanic bulla. These differences were related to a more refined echolocalization system that likely enhances the exploitation of local resources by philopatric females. Distinct shape in immature versus mature stages and asymmetric changes in postnatal allometry of dorsal and occipital traits, suggest that differences between males and females are established early during growth. Allometric growth trajectories differed between males and females for the ventral view of the skull. Allometric trajectories differed among projections of skull and mandible, and were related to dietary

  14. Non-Trivial Feature Derivation for Intensifying Feature Detection Using LIDAR Datasets Through Allometric Aggregation Data Analysis Applying Diffused Hierarchical Clustering for Discriminating Agricultural Land Cover in Portions of Northern Mindanao, Philippines

    NASA Astrophysics Data System (ADS)

    Villar, Ricardo G.; Pelayo, Jigg L.; Mozo, Ray Mari N.; Salig, James B., Jr.; Bantugan, Jojemar

    2016-06-01

    Leaning on the derived results conducted by Central Mindanao University Phil-LiDAR 2.B.11 Image Processing Component, the paper attempts to provides the application of the Light Detection and Ranging (LiDAR) derived products in arriving quality Landcover classification considering the theoretical approach of data analysis principles to minimize the common problems in image classification. These are misclassification of objects and the non-distinguishable interpretation of pixelated features that results to confusion of class objects due to their closely-related spectral resemblance, unbalance saturation of RGB information is a challenged at the same time. Only low density LiDAR point cloud data is exploited in the research denotes as 2 pts/m2 of accuracy which bring forth essential derived information such as textures and matrices (number of returns, intensity textures, nDSM, etc.) in the intention of pursuing the conditions for selection characteristic. A novel approach that takes gain of the idea of object-based image analysis and the principle of allometric relation of two or more observables which are aggregated for each acquisition of datasets for establishing a proportionality function for data-partioning. In separating two or more data sets in distinct regions in a feature space of distributions, non-trivial computations for fitting distribution were employed to formulate the ideal hyperplane. Achieving the distribution computations, allometric relations were evaluated and match with the necessary rotation, scaling and transformation techniques to find applicable border conditions. Thus, a customized hybrid feature was developed and embedded in every object class feature to be used as classifier with employed hierarchical clustering strategy for cross-examining and filtering features. This features are boost using machine learning algorithms as trainable sets of information for a more competent feature detection. The product classification in this

  15. Massive Halos in Millennium Gas Simulations: Multivariate Scaling Relations

    NASA Astrophysics Data System (ADS)

    Stanek, R.; Rasia, E.; Evrard, A. E.; Pearce, F.; Gazzola, L.

    2010-06-01

    The joint likelihood of observable cluster signals reflects the astrophysical evolution of the coupled baryonic and dark matter components in massive halos, and its knowledge will enhance cosmological parameter constraints in the coming era of large, multiwavelength cluster surveys. We present a computational study of intrinsic covariance in cluster properties using halo populations derived from Millennium Gas Simulations (MGS). The MGS are re-simulations of the original 500 h -1 Mpc Millennium Simulation performed with gas dynamics under two different physical treatments: shock heating driven by gravity only (GO) and a second treatment with cooling and preheating (PH). We examine relationships among structural properties and observable X-ray and Sunyaev-Zel'dovich (SZ) signals for samples of thousands of halos with M 200 >= 5 × 1013 h -1 M sun and z < 2. While the X-ray scaling behavior of PH model halos at low redshift offers a good match to local clusters, the model exhibits non-standard features testable with larger surveys, including weakly running slopes in hot gas observable-mass relations and ~10% departures from self-similar redshift evolution for 1014 h -1 M sun halos at redshift z ~ 1. We find that the form of the joint likelihood of signal pairs is generally well described by a multivariate, log-normal distribution, especially in the PH case which exhibits less halo substructure than the GO model. At fixed mass and epoch, joint deviations of signal pairs display mainly positive correlations, especially the thermal SZ effect paired with either hot gas fraction (r = 0.88/0.69 for PH/GO at z = 0) or X-ray temperature (r = 0.62/0.83). The levels of variance in X-ray luminosity, temperature, and gas mass fraction are sensitive to the physical treatment, but offsetting shifts in the latter two measures maintain a fixed 12% scatter in the integrated SZ signal under both gas treatments. We discuss halo mass selection by signal pairs, and find a minimum mass

  16. Establishing and Understanding Adsorption-Energy Scaling Relations with Negative Slopes.

    PubMed

    Su, Hai-Yan; Sun, Keju; Wang, Wei-Qi; Zeng, Zhenhua; Calle-Vallejo, Federico; Li, Wei-Xue

    2016-12-15

    Adsorption-energy scaling relations are widely used for the design of catalytic materials. To date, only linear scaling relations are known in which the slopes are positive. Considering the adsorption energies of F, O, N, C, and B on transition metals, we show here that scaling relations with negative slopes also exist between certain adsorbates. The origin of such unconventional scaling relations is analyzed in terms of common descriptors such as d-band center, work function, number of outer electrons, electronic charge on the adsorbates, integrated crystal orbital overlap populations, and crystal orbital Hamilton populations. Conventional scaling relations are formed between adsorbates such as F, O, N, and C, which create ionic-like bonds with surfaces. Conversely, anomalous scaling relations are established between those and covalently bound adsorbates such as B. This widens the theory of adsorption-energy scaling relations and opens new avenues in physical chemistry and catalysis, for instance, in direct borohydride fuel cells.

  17. 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

  18. 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

  19. Phase relations of triadic scale interactions in turbulent flows

    NASA Astrophysics Data System (ADS)

    Duvvuri, Subrahmanyam; McKeon, Beverley

    2014-11-01

    The quadratic nature of non-linearity in the Navier-Stokes (NS) equations dictates the coupling between scales in a turbulent flow to be of triadic form. An understanding of the triadic coupling affords good insights into the dynamics of turbulence, as demonstrated by Sharma & McKeon (J. Fluid Mech., 2013) through analysis of the NS resolvent operator; a set of three triadically consistent spatio-temporal modes was shown to produce complex structures such as modulating packets of hairpin vortices observed in wall-bounded turbulent flows. Here we interpret Skewness (Sk) of velocity fluctuations and the Amplitude Modulation coefficient (Ram), proposed by Mathis, Hutchins & Marusic (J. Fluid Mech., 2009), to be a measure of the large- and small-scale phase relationship. Through a simple decomposition of scales, both Sk and Ram are shown to be amplitude weighted (and normalized) measures of phase between scales that have direct triadic coupling. An analytical relationship is established between the two quantities and the result is demonstrated using experimental data from canonical and dynamically forced turbulent boundary layers presented in Duvvuri and McKeon (AIAA 2014-2883). The support of AFOSR (Grant No. FA 9550-12-1-0469) and Resnick Institute Graduate Research Fellowship (S.D.) is gratefully acknowledged.

  20. Allometric ecological distributions in a local community of Hymenoptera

    NASA Astrophysics Data System (ADS)

    Ulrich, Werner

    2004-05-01

    The present paper describes basic ecological distributions in a community of beech forest Hymenoptera. It shows that the species diversity-body weight and the density-body weight distributions give rise to a new distribution that relates total community biomass to species diversity. For Hymenoptera this distribution follows a power function with a slope of 1.3. Combining this relation with the species-area and the individuals-area relations resulted in two other distributions that relate community biomass to area and individual numbers. It appeared that population densities decrease when computed over larger areas. The biomass-species diversity relation offers a new and simple way to estimate total community biomass from samples. The possible implications of this distribution to the productivity-diversity debate are discussed.

  1. Scaling Relations of Mass, Velocity, and Radius for Disk Galaxies

    NASA Astrophysics Data System (ADS)

    Schulz, Earl

    2017-02-01

    I demonstrate four tight correlations of total baryonic mass, velocity, and radius for a set of nearby disk galaxies: the mass–velocity relation {M}{{t}}\\propto {V}4; the mass–radius relation {M}{{t}}\\propto {R}2; the radius–velocity relation R\\propto {V}2; and the mass–radius–velocity relation {M}{{t}}\\propto {{RV}}2. The mass–velocity relation is the familiar Baryonic Tully–Fisher relation, and versions of the other three relations, using magnitude rather than baryonic mass, are also well known. These four observed correlations follow from a pair of more fundamental relations. First, the centripetal acceleration at the edge of the stellar disk is proportional to the acceleration predicted by Newtonian physics, and second, this acceleration is a constant that is related to Milgrom’s constant. The two primary relations can be manipulated algebraically to generate the four observed correlations and allow little room for dark matter inside the radius of the stellar disk. The primary relations do not explain the velocity of the outer gaseous disks of spiral galaxies, which do not trace the Newtonian gravitational field of the observed matter.

  2. Development & Validation of a PTSD-Related Impairment Scale

    DTIC Science & Technology

    2013-06-01

    funded randomized controlled study will be on the effectiveness of mind-body skills like meditation , biofeedback, guided imagery on PTSD, sleep...Education: This scale assesses the extent to which the individual can focus in the classroom and complete homework assignments in an effective and...December 2009. The data collections will be done in on-post facilities such as theaters, gymnasiums, classrooms , and at assigned training locations

  3. 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.

  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. Relativity of Scales: Application to AN Endo-Perspective of Temporal Structures

    NASA Astrophysics Data System (ADS)

    Nottale, Laurent; Timar, Pierre

    The theory of scale relativity is an extension of the principle of relativity to scale transformations of the reference system, in a fractal geometry framework where coordinates become explicitly dependent on resolutions. Applied to an observer perspective, it means that the scales of length and of time, usually attributed to the observed object as being intrinsic to it, have actually no existence by themselves, since only the ratio between an external scale and an internal scale, which serves as unit, is meaningful. Oliver Sacks' observations on patients suffering from temporal and spatial distortions in Parkinson's and encephalitis lethargica disease offer a particularly relevant field of application for such a scale-relativistic view.

  6. The scaling of frontal cortex in primates and carnivores

    PubMed Central

    Bush, Eliot C.; Allman, John M.

    2004-01-01

    Size has a profound effect on the structure of the brain. Many brain structures scale allometrically, that is, their relative size changes systematically as a function of brain size. Here we use independent contrasts analysis to examine the scaling of frontal cortex in 43 species of mammals including 25 primates and 15 carnivores. We find evidence for significant differences in scaling between primates and carnivores. Primate frontal cortex hyperscales relative to the rest of neocortex and the rest of the brain. The slope of frontal cortex contrasts on rest of cortex contrasts is 1.18 (95% confidence interval, 1.06-1.30) for primates, which is significantly greater than isometric. It is also significantly greater than the carnivore value of 0.94 (95% confidence interval, 0.82-1.07). This finding supports the idea that there are substantial differences in frontal cortex structure and development between the two groups. PMID:15007170

  7. 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

  8. Spatial patterns of correlated scale size and scale color in relation to color pattern elements in butterfly wings.

    PubMed

    Iwata, Masaki; Otaki, Joji M

    2016-02-01

    Complex butterfly wing color patterns are coordinated throughout a wing by unknown mechanisms that provide undifferentiated immature scale cells with positional information for scale color. Because there is a reasonable level of correspondence between the color pattern element and scale size at least in Junonia orithya and Junonia oenone, a single morphogenic signal may contain positional information for both color and size. However, this color-size relationship has not been demonstrated in other species of the family Nymphalidae. Here, we investigated the distribution patterns of scale size in relation to color pattern elements on the hindwings of the peacock pansy butterfly Junonia almana, together with other nymphalid butterflies, Vanessa indica and Danaus chrysippus. In these species, we observed a general decrease in scale size from the basal to the distal areas, although the size gradient was small in D. chrysippus. Scales of dark color in color pattern elements, including eyespot black rings, parafocal elements, and submarginal bands, were larger than those of their surroundings. Within an eyespot, the largest scales were found at the focal white area, although there were exceptional cases. Similarly, ectopic eyespots that were induced by physical damage on the J. almana background area had larger scales than in the surrounding area. These results are consistent with the previous finding that scale color and size coordinate to form color pattern elements. We propose a ploidy hypothesis to explain the color-size relationship in which the putative morphogenic signal induces the polyploidization (genome amplification) of immature scale cells and that the degrees of ploidy (gene dosage) determine scale color and scale size simultaneously in butterfly wings.

  9. REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS

    SciTech Connect

    Cassano, R.; Brunetti, G.; Venturi, T.; Kale, R.; Pratt, G. W.; Markevitch, M.

    2013-11-10

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R{sub 500} as P{sub 1.4}∼L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) clusters branch into two populations—radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P{sub 1.4} scales with the cluster integrated SZ signal within R{sub 500}, measured by Planck, as P{sub 1.4}∼Y{sup 2.05±0.28}{sub 500}, in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that 'SZ-luminous' Y{sub 500} > 6 × 10{sup –5} Mpc{sup 2} clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle

  10. Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Cassano, R.; Ettori, S.; Brunetti, G.; Giacintucci, S.; Pratt, G. W.; Venturi, T.; Kale, R.; Dolag, K.; Markevitch, Maxim L.

    2013-01-01

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R(sub 500) as P(sub 1.4) approx. L(2.1+/-0.2) - 500). Our bigger and more homogenous sample confirms that the X-ray luminous (L(sub 500) > 5 × 10(exp 44) erg/s)) clusters branch into two populations-radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P(sub 1.4) scales with the cluster integrated SZ signal within R(sub 500), measured by Planck, as P(sub 1.4) approx. Y(2.05+/-0.28) - 500), in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that "SZ-luminous" Y(sub 500) > 6×10(exp -5) Mpc(exp 2) clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle acceleration.

  11. Understanding the relative role of dispersion mechanisms across basin scales

    NASA Astrophysics Data System (ADS)

    Di Lazzaro, M.; Zarlenga, A.; Volpi, E.

    2016-05-01

    Different mechanisms are understood to represent the primary sources of the variance of travel time distribution in natural catchments. To quantify the fraction of variance introduced by each component, dispersion coefficients have been earlier defined in the framework of geomorphology-based rainfall-runoff models. In this paper we compare over a wide range of basin sizes and for a variety of runoff conditions the relative role of geomorphological dispersion, related to the heterogeneity of path lengths, and hillslope kinematic dispersion, generated by flow processes within the hillslopes. Unlike previous works, our approach does not focus on a specific study case; instead, we try to generalize results already obtained in previous literature stemming from the definition of a few significant parameters related to the metrics of the catchment and flow dynamics. We further extend this conceptual framework considering the effects of two additional variance-producing processes: the first covers the random variability of hillslope velocities (i.e. of travel times over hillslopes); the second deals with non-uniform production of runoff over the basin (specifically related to drainage density). Results are useful to clarify the role of hillslope kinematic dispersion and define under which conditions it counteracts or reinforces geomorphological dispersion. We show how its sign is ruled by the specific spatial distribution of hillslope lengths within the basin, as well as by flow conditions. Interestingly, while negative in a wide range of cases, kinematic dispersion is expected to become invariantly positive when the variability of hillslope velocity is large.

  12. Time scales in the context of general relativity.

    PubMed

    Guinot, Bernard

    2011-10-28

    Towards 1967, the accuracy of caesium frequency standards reached such a level that the relativistic effect could not be ignored anymore. Corrections began to be applied for the gravitational frequency shift and for distant time comparisons. However, these corrections were not applied to an explicit theoretical framework. Only in 1991 did the International Astronomical Union provide metrics (then improved in 2000) for a definition of space-time coordinates in reference systems centred at the barycentre of the Solar System and at the centre of mass of the Earth. In these systems, the temporal coordinates (coordinate times) can be realized on the basis of one of them, the International Atomic Time (TAI), which is itself a realized time scale. The definition and the role of TAI in this context will be recalled. There remain controversies regarding the name to be given to the unit of coordinate times and to other quantities appearing in the theory. However, the idea that astrometry and celestial mechanics should adopt the usual metrological rules is progressing, together with the use of the International System of Units, among astronomers.

  13. Relative scaling of mode shapes using transmissibility functions

    NASA Astrophysics Data System (ADS)

    Weijtjens, Wout; De Sitter, Gert; Devriendt, Christof; Guillaume, Patrick

    2013-10-01

    Operational modal analysis (OMA) is the collective term for different techniques that estimate the modal parameters of a linear structure using only the structural responses to unknown excitations. Therefore, OMA is the preferred approach when operational forces are hard to measure, when operational conditions are hard to replicate in a controlled environment or when an experimental modal analysis (EMA) is too time-consuming. However, OMA does not allow us to determine the relative contribution of each mode, i.e. the mode shapes found with OMA are unscaled. This paper introduces a novel approach to estimate the relative contributions of all modes within a given bandwidth and to reconstruct frequency response functions (FRF) that are proportional to the true FRFs of the system. This novel technique requires only response data and a general knowledge of the input locations of the dominant forces acting on the system. It is shown that even when only a limited number of input locations are known the proposed method can still be used by considering multiple loading conditions. Finally, since the technique is based on transmissibility functions, there are no necessary assumptions considering the spectral content of the excitations. Several numerical examples illustrate the claimed properties and are used to quantify the influence of measurement and ambient noise.

  14. Modeling relative frost weathering rates at geomorphic scales

    NASA Astrophysics Data System (ADS)

    Rempel, Alan W.; Marshall, Jill A.; Roering, Joshua J.

    2016-11-01

    Frost damage is a powerful agent of geomorphic change. Cracks can grow when the ice pressure in pores reaches a threshold that depends on matrix properties and crack geometry. Mineral surfaces that are preferentially wetted by liquid water rather than ice are coated by premelted liquid at a pressure that is lower than the ice pressure. Because this pressure difference increases as the temperature cools, when the ice pressure is effectively pinned at the cracking threshold, temperature gradients induce gradients in liquid pressure that draw water towards colder temperatures. Porosity increases and frost damage accumulates in regions where water supplies crack growth. To apply this understanding over the large spatial and temporal scales that are relevant to evolving landscapes, we develop a simple model that tracks porosity changes. Our central assumption is that frost damage is correlated with porosity increases under conditions where frost cracking takes place. Accordingly, we account for the permeability reductions with decreased temperature that accompany ice growth along porous pathways and derive general expressions for the porosity change through time at particular depths, as well as the total porosity increase through all depths beneath a point at the ground surface over the time during which cracking occurs each year. To illustrate the resulting patterns of frost weathering, we consider a general case in which the permeability has a power law dependence on temperature and the annual surface-temperature variation is sinusoidal. We find that the degree of frost damage generally decreases with depth, except at localized depths where damage is elevated because the rock spends longer times near the threshold for cracking, leading to enhanced water supply in comparison with neighboring regions. The magnitude of the net expansion that results from porosity changes at all depths beneath the ground surface is increased for seasonal thermal cycles with larger

  15. 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

  16. Universal scaling of respiratory metabolism, size and nitrogen in plants.

    PubMed

    Reich, Peter B; Tjoelker, Mark G; Machado, Jose-Luis; Oleksyn, Jacek

    2006-01-26

    The scaling of respiratory metabolism to body size in animals is considered to be a fundamental law of nature, and there is substantial evidence for an approximate (3/4)-power relation. Studies suggest that plant respiratory metabolism also scales as the (3/4)-power of mass, and that higher plant and animal scaling follow similar rules owing to the predominance of fractal-like transport networks and associated allometric scaling. Here, however, using data obtained from about 500 laboratory and field-grown plants from 43 species and four experiments, we show that whole-plant respiration rate scales approximately isometrically (scaling exponent approximately 1) with total plant mass in individual experiments and has no common relation across all data. Moreover, consistent with theories about biochemically based physiological scaling, isometric scaling of whole-plant respiration rate to total nitrogen content is observed within and across all data sets, with a single relation common to all data. This isometric scaling is unaffected by growth conditions including variation in light, nitrogen availability, temperature and atmospheric CO2 concentration, and is similar within or among species or functional groups. These findings suggest that plants and animals follow different metabolic scaling relations, driven by distinct mechanisms.

  17. Scaling the relative dominance of exogenous drivers in structuring desert small mammal assemblages

    NASA Astrophysics Data System (ADS)

    Rodríguez, Daniela; Ojeda, Ricardo A.

    2015-11-01

    Assemblage patterns could be primarily generated by two types of drivers: exogenous (such as environmental and climatic factors) and endogenous (interactions such as competition, predation, mutualism or herbivory). The most widely accepted hypothesis states that at smaller scales (such as patch scale), interspecific interactions are the major drivers structuring communities, whereas at larger regional scales, factors such as climate, topography and soil act as ecological filters that determine assemblage composition. The general aim of this paper is to compare different exogenous drivers in terms of their relative dominance in structuring desert small mammal communities across a range of spatial scales, from patch to regional, and compare them with previous results on endogenous drivers. Our results show that as spatial scale increases, the explanatory power of exogenous factors also increases, e.g. from 17% at the patch scale (i.e. abundance) to 99% at the regional scale (i.e. diversity). Moreover, environmental drivers vary in type and strength depending on the community estimator across several spatial scales. On the other hand, endogenous drivers such as interspecific interactions are more important at the patch scale, diminishing in importance towards the regional scale. Therefore, the relative importance of exogenous versus endogenous drivers affects small mammal assemblage structure at different spatial scales. Our results fill up a knowledge gap concerning ecological drivers of assemblage structure at intermediate spatial scales for Monte desert small mammals, and highlight the importance of dealing with multi-causal factors in explaining ecological patterns of assemblages.

  18. The Individual and Relational Role Balance Scale (IRRBS): A Preliminary Scale Development and Validation Study

    ERIC Educational Resources Information Center

    Bishop, Jennifer L.; Welsh, Deborah P.; Lounsbury, John W.; Norona, Jerika C.

    2016-01-01

    During emerging adulthood, young people begin the process of balancing individual and relational role commitments. Whereas development within specific domains, primarily career and relationship (work and love), have been explored separately, it is important to understand how emerging adults divide their attention across multiple individual (i.e.,…

  19. Nano scale devices: Fabrication, actuation, and related fluidic dynamics

    NASA Astrophysics Data System (ADS)

    Jing, Hao

    cilia beating through the use of magnetic nanowires. We apply our custom magnetic system, 3DFM, to drive these magnetic nanowires rotating with desired patterns and frequencies in a liquid chamber. High speed movies of passive tracers in the oscillating 3-D flow fields reveal the spatio-temporal structure of the induced fluid motion. Complementing these experimental studies, we have developed a family of exact solutions of the Stoke's equations for a spheroid sweeping a double cone in free space, and an asymptotic solution for a spinning slender rod sweeping an upright cone above a flat, infinite no-slip plane. We are using these solutions to develop a mathematical package to quantitatively model, and predict the tracer motion induced by the spinning nano-rods with and without Brownian noise. To understand the effect of these epicyclical flows on molecular conformations, we have studied the conformation of fluorescently labeled, single DNA molecules (lambda-DNA) in the flow produced by a precessing nanowire. The flow patterns in a viscoelastic medium about a precessing nanowire are also presented to reveal the epicyclical flows in a more bio-related environment.

  20. 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.

  1. The size, scale, and shape of cities.

    PubMed

    Batty, Michael

    2008-02-08

    Despite a century of effort, our understanding of how cities evolve is still woefully inadequate. Recent research, however, suggests that cities are complex systems that mainly grow from the bottom up, their size and shape following well-defined scaling laws that result from intense competition for space. An integrated theory of how cities evolve, linking urban economics and transportation behavior to developments in network science, allometric growth, and fractal geometry, is being slowly developed. This science provides new insights into the resource limits facing cities in terms of the meaning of density, compactness, and sprawl, and related questions of sustainability. It has the potential to enrich current approaches to city planning and replace traditional top-down strategies with realistic city plans that benefit all city dwellers.

  2. The scaling of postcranial muscles in cats (Felidae) II: hindlimb and lumbosacral muscles.

    PubMed

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

    2016-07-01

    In quadrupeds the musculature of the hindlimbs is expected to be responsible for generating most of the propulsive locomotory forces, as well as contributing to body support by generating vertical forces. In supporting the body, postural changes from crouched to upright limbs are often associated with an increase of body mass in terrestrial tetrapods. However, felids do not change their crouched limb posture despite undergoing a 300-fold size increase between the smallest and largest extant species. Here, we test how changes in the muscle architecture (masses and lengths of components of the muscle-tendon units) of the hindlimbs and lumbosacral region are related to body mass, to assess whether there are muscular compensations for the maintenance of a crouched limb posture at larger body sizes. We use regression and principal component analyses to detect allometries in muscle architecture, with and without phylogenetic correction. Of the muscle lengths that scale allometrically, all scale with negative allometry (i.e. relative shortening with increasing body mass), whereas all tendon lengths scale isometrically. Only two muscles' belly masses and two tendons' masses scale with positive allometry (i.e. relatively more massive with increasing body mass). Of the muscles that scale allometrically for physiological cross-sectional area, all scale positively (i.e. relatively greater area with increasing body mass). These muscles are mostly linked to control of hip and thigh movements. When the architecture data are phylogenetically corrected, there are few significant results, and only the strongest signals remain. None of the vertebral muscles scaled significantly differently from isometry. Principal component analysis and manovas showed that neither body size nor locomotor mode separate the felid species in morphospace. Our results support the inference that, despite some positively allometric trends in muscle areas related to thigh movement, larger cats have

  3. Working memory performance inversely predicts spontaneous delta and theta-band scaling relations.

    PubMed

    Euler, Matthew J; Wiltshire, Travis J; Niermeyer, Madison A; Butner, Jonathan E

    2016-04-15

    Electrophysiological studies have strongly implicated theta-band activity in human working memory processes. Concurrently, work on spontaneous, non-task-related oscillations has revealed the presence of long-range temporal correlations (LRTCs) within sub-bands of the ongoing EEG, and has begun to demonstrate their functional significance. However, few studies have yet assessed the relation of LRTCs (also called scaling relations) to individual differences in cognitive abilities. The present study addressed the intersection of these two literatures by investigating the relation of narrow-band EEG scaling relations to individual differences in working memory ability, with a particular focus on the theta band. Fifty-four healthy adults completed standardized assessments of working memory and separate recordings of their spontaneous, non-task-related EEG. Scaling relations were quantified in each of the five classical EEG frequency bands via the estimation of the Hurst exponent obtained from detrended fluctuation analysis. A multilevel modeling framework was used to characterize the relation of working memory performance to scaling relations as a function of general scalp location in Cartesian space. Overall, results indicated an inverse relationship between both delta and theta scaling relations and working memory ability, which was most prominent at posterior sensors, and was independent of either spatial or individual variability in band-specific power. These findings add to the growing literature demonstrating the relevance of neural LRTCs for understanding brain functioning, and support a construct- and state-dependent view of their functional implications.

  4. 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.

  5. Validation of the Career-Related Parent Support Scale among Chinese High School Students

    ERIC Educational Resources Information Center

    Cheng, Sandra; Yuen, Mantak

    2012-01-01

    The Career-Related Parent Support Scale (CRPSS; Turner, Alliman-Brissett, Lapan, Udipi, & Ergun, 2003) was translated and modified to form the 24-item Chinese version of the scale. As in the case of the original CRPSS, the Chinese version includes 4 subscales (Instrumental Assistance, Emotional Support, Verbal Encouragement, and Career-Related…

  6. Scaling adult doses of antifungal and antibacterial agents to children.

    PubMed

    Dawson, Thomas H

    2012-06-01

    My general pharmacokinetic scaling theory is discussed for the important matter of determining pediatric dosing for existing and new therapeutic drugs when optimal, or near-optimal, dosing for adults is known. The basis for the scaling is the requirement of a time-scaled likeness of the free-drug concentration time histories of children and adults. Broad categories of single and periodic dosing are considered. The former involves the scaling of dosage, and the latter involves both the dosage and schedule. The validity of the scaling relations is demonstrated by using measurements from previously reported clinical trials with adults and children (with ages generally 1 year or older) for the relatively new antifungal agent caspofungin and for the relatively new antibacterial agent linezolid. Standard pharmacodynamic effectiveness criteria are shown to be satisfied for the scaled dosage and schedule for children to the same extent that they are for the referenced adult. Consideration of scaling from adults to children is discussed for the case of new agents where no pediatric data are available and needed parameters are determined from in vitro measurements and preclinical animal data. A connection is also made between the allometric representation of clearance data and the dosing formulas. Limitations of the scaling results for infants because of growth and maturational matters are discussed. The general conclusion from this work is that the scaling theory does indeed have application to pediatric dosing for children, for both confirmation and refinement of present practice and guidance in pediatric treatment with new therapeutic agents.

  7. Scale effects and morphological diversification in hindlimb segment mass proportions in neognath birds

    PubMed Central

    2014-01-01

    Introduction In spite of considerable work on the linear proportions of limbs in amniotes, it remains unknown whether differences in scale effects between proximal and distal limb segments has the potential to influence locomotor costs in amniote lineages and how changes in the mass proportions of limbs have factored into amniote diversification. To broaden our understanding of how the mass proportions of limbs vary within amniote lineages, I collected data on hindlimb segment masses – thigh, shank, pes, tarsometatarsal segment, and digits – from 38 species of neognath birds, one of the most speciose amniote clades. I scaled each of these traits against measures of body size (body mass) and hindlimb size (hindlimb length) to test for departures from isometry. Additionally, I applied two parameters of trait evolution (Pagel’s λ and δ) to understand patterns of diversification in hindlimb segment mass in neognaths. Results All segment masses are positively allometric with body mass. Segment masses are isometric with hindlimb length. When examining scale effects in the neognath subclade Land Birds, segment masses were again positively allometric with body mass; however, shank, pedal, and tarsometatarsal segment masses were also positively allometric with hindlimb length. Methods of branch length scaling to detect phylogenetic signal (i.e., Pagel’s λ) and increasing or decreasing rates of trait change over time (i.e., Pagel’s δ) suffer from wide confidence intervals, likely due to small sample size and deep divergence times. Conclusions The scaling of segment masses appears to be more strongly related to the scaling of limb bone mass as opposed to length, and the scaling of hindlimb mass distribution is more a function of scale effects in limb posture than proximo-distal differences in the scaling of limb segment mass. Though negative allometry of segment masses appears to be precluded by the need for mechanically sound limbs, the positive allometry of

  8. 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

  9. [Development of the Trait Respect-Related Emotions Scale for late adolescence].

    PubMed

    Muto, Sera

    2016-02-01

    This study developed a scale to measure the respect-related emotional traits (the Trait Respect-Related Emotions Scale) for late adolescence and examined the reliability and validity. In study 1,368 university students completed the items of the Trait Respect-Related Emotions Scale and other scales of theoretically important personality constructs including adult attachment style, the "Big Five," self-esteem, and two types of narcissistic personality. Factor analysis indicated that there are three factors of trait respect-related emotions: (a) trait (prototypical) respect; (b) trait idolatry (worship and adoration); and (c) trait awe. The three traits associated differentially with the daily experience (frequency) of the five basic respect-related emotions (prototypical respect, idolatry, awe, admiration, and wonder), and other constructs. In Study 2, a test-retest correlation of the new scale with 60 university students indicated good reliability. Both studies generally supported the reliability and validity of the new scale. These findings suggest that, at Ieast in late adolescence, there are large individual differences in respect-related emotion experiences and the trait of respect should be considered as multi-dimensional structure.

  10. Length scales in glass-forming liquids and related systems: a review

    NASA Astrophysics Data System (ADS)

    Karmakar, Smarajit; Dasgupta, Chandan; Sastry, Srikanth

    2016-01-01

    The central problem in the study of glass-forming liquids and other glassy systems is the understanding of the complex structural relaxation and rapid growth of relaxation times seen on approaching the glass transition. A central conceptual question is whether one can identify one or more growing length scale(s) associated with this behavior. Given the diversity of molecular glass-formers and a vast body of experimental, computational and theoretical work addressing glassy behavior, a number of ideas and observations pertaining to growing length scales have been presented over the past few decades, but there is as yet no consensus view on this question. In this review, we will summarize the salient results and the state of our understanding of length scales associated with dynamical slow down. After a review of slow dynamics and the glass transition, pertinent theories of the glass transition will be summarized and a survey of ideas relating to length scales in glassy systems will be presented. A number of studies have focused on the emergence of preferred packing arrangements and discussed their role in glassy dynamics. More recently, a central object of attention has been the study of spatially correlated, heterogeneous dynamics and the associated length scale, studied in computer simulations and theoretical analysis such as inhomogeneous mode coupling theory. A number of static length scales have been proposed and studied recently, such as the mosaic length scale discussed in the random first-order transition theory and the related point-to-set correlation length. We will discuss these, elaborating on key results, along with a critical appraisal of the state of the art. Finally we will discuss length scales in driven soft matter, granular fluids and amorphous solids, and give a brief description of length scales in aging systems. Possible relations of these length scales with those in glass-forming liquids will be discussed.

  11. 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.

  12. 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

  13. 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.

  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 local species-habitat relations to the larger landscape with a hierarchical spatial count model

    USGS Publications Warehouse

    Thogmartin, W.E.; Knutson, M.G.

    2007-01-01

    Much of what is known about avian species-habitat relations has been derived from studies of birds at local scales. It is entirely unclear whether the relations observed at these scales translate to the larger landscape in a predictable linear fashion. We derived habitat models and mapped predicted abundances for three forest bird species of eastern North America using bird counts, environmental variables, and hierarchical models applied at three spatial scales. Our purpose was to understand habitat associations at multiple spatial scales and create predictive abundance maps for purposes of conservation planning at a landscape scale given the constraint that the variables used in this exercise were derived from local-level studies. Our models indicated a substantial influence of landscape context for all species, many of which were counter to reported associations at finer spatial extents. We found land cover composition provided the greatest contribution to the relative explained variance in counts for all three species; spatial structure was second in importance. No single spatial scale dominated any model, indicating that these species are responding to factors at multiple spatial scales. For purposes of conservation planning, areas of predicted high abundance should be investigated to evaluate the conservation potential of the landscape in their general vicinity. In addition, the models and spatial patterns of abundance among species suggest locations where conservation actions may benefit more than one species. ?? 2006 Springer Science+Business Media B.V.

  16. Fitness consequences of artificial selection on relative male genital size

    PubMed Central

    Booksmythe, Isobel; Head, Megan L.; Keogh, J. Scott; Jennions, Michael D.

    2016-01-01

    Male genitalia often show remarkable differences among related species in size, shape and complexity. Across poeciliid fishes, the elongated fin (gonopodium) that males use to inseminate females ranges from 18 to 53% of body length. Relative genital size therefore varies greatly among species. In contrast, there is often tight within-species allometric scaling, which suggests strong selection against genital–body size combinations that deviate from a species' natural line of allometry. We tested this constraint by artificially selecting on the allometric intercept, creating lines of males with relatively longer or shorter gonopodia than occur naturally for a given body size in mosquitofish, Gambusia holbrooki. We show that relative genital length is heritable and diverged 7.6–8.9% between our up-selected and down-selected lines, with correlated changes in body shape. However, deviation from the natural line of allometry does not affect male success in assays of attractiveness, swimming performance and, crucially, reproductive success (paternity). PMID:27188478

  17. 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

  18. Psychometric Evaluation of Data from the Race-Related Events Scale

    ERIC Educational Resources Information Center

    Crusto, Cindy A.; Dantzler, John; Roberts, Yvonne Humenay; Hooper, Lisa M.

    2015-01-01

    Using exploratory factor analysis, we examined the factor structure of data collected from the Race-Related Events Scale, which assesses perceived exposure to race-related stress. Our sample (N = 201) consisted of diverse caregivers of Head Start preschoolers. Three factors explained 81% of the variance in the data and showed sound reliability.

  19. Reliability of a Scale of Work-Related Self-Efficacy for People with Psychiatric Disabilities

    ERIC Educational Resources Information Center

    Harris, Meredith

    2010-01-01

    Work-related self-efficacy at a core task level fits with the social cognitive career theory explaining the career development of people with severe mental illness. The aim of this study was to further investigate the psychometric properties of the "Work-related Self- Efficacy Scale" for use with people with psychiatric disabilities. Sixty…

  20. Eysenck Personality Questionnaire scales and paper-and-pencil tests related to creativity.

    PubMed

    Schuldberg, David

    2005-08-01

    Pearson correlations for scores on scales of the 1975 version of the Eysenck Personality Questionnaire with measures of schizotypy, hypomania, and creative traits are reported for 625 undergraduates. The Psychoticism scores are correlated .30 with Hypomanic traits, .25 with Perceptual Aberration, and .20 with the How Do You Think, a test of attitudes and activities related to creativity. Extraversion is also related to creativity-relevant scores. Results support a broad and nonspecific role for the Psychoticism scale in relation to both creativity and subclinical symptomatology.

  1. 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.

  2. Planck-scale-modified dispersion relations in homogeneous and isotropic spacetimes

    NASA Astrophysics Data System (ADS)

    Barcaroli, Leonardo; Brunkhorst, Lukas K.; Gubitosi, Giulia; Loret, Niccoló; Pfeifer, Christian

    2017-01-01

    The covariant understanding of dispersion relations as level sets of Hamilton functions on phase space enables us to derive the most general dispersion relation compatible with homogeneous and isotropic spacetimes. We use this concept to present a Planck-scale deformation of the Hamiltonian of a particle in Friedman-Lemaître-Robertson-Walker (FLRW) geometry that is locally identical to the κ -Poincaré dispersion relation, in the same way as the dispersion relation of point particles in general relativity is locally identical to the one valid in special relativity. Studying the motion of particles subject to such a Hamiltonian, we derive the redshift and lateshift as observable consequences of the Planck-scale deformed FLRW universe.

  3. An estimate of the relative magnitude of small-scale tracer fluxes

    NASA Technical Reports Server (NTRS)

    Bacmeister, Julio T.; Schoeberl, Mark R.; Loewenstein, Max; Podolske, Jim R.; Strahan, Susan E.; Chan, K. R.

    1992-01-01

    The wind and constituent measurements from the polar aircraft data are used to compute the flux spectra. Although there is variation from flight to flight, the flux spectra generally fit a -2 to -1.5 power law as expected theoretically. This result suggests that tracer fluxes from small scale features do not substantially contribute to the overall tracer budget relative to the fluxes from the larger scales.

  4. Scale-dependent relative dispersion measurements from the Grand LAgrangian Deployment (GLAD)

    NASA Astrophysics Data System (ADS)

    Haza, Angelique; Poje, Andrew; Ozgokmen, Tamay; Griffa, Annalisa; Haus, Brian; Huntley, Helga; Hogan, Patrick; Jacobs, Gregg; Kirwan, Danny; Lipphardt, Bruce; Novelli, Guillaume; Olascoaga, Josefina; Beron-Vera, Francisco; Reniers, Ad; Ryan, Edward

    2013-04-01

    The scale-dependent Lagrangian dispersion metrics, such as the Finite Scale Lyapunov Exponent, are suitable to study multi-scale interaction of ocean flows. Of particular interest is the possible impact of submesoscale flows on transport in the ocean, for applied problems such as oil spill. Results will be presented from the GLAD experiment, which was configured to optimize in-situ submesoscale relative dispersion measurements in the Gulf of Mexico near DeSoto Canyon from a release of more than 300 surface drifters.

  5. 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 ...

  6. An investigation of integral facility scaling and data relation methods (Integral System Test Program)

    SciTech Connect

    Larson, T K

    1987-02-01

    The Integral Systems Test (IST) Program was initiated in 1982 by government and industry to provide information needed to help resolve issues raised by the accident at the Three Mile Island nuclear power station. Three different integral test facilities, each scaled to a Babcock and Wilcox (B and W) design nuclear steam supply system, will ultimately contribute data to meet the objectives of the program. Each of the facilities was designed using different scaling methodologies, and each has different operating capabilities, such as maximum operating pressure and core power. The overall scaling of each facility is examined in this report, and local scaling is analyzed to demonstrate potential similarities and dissimilarities in facility response relative to expected plant responses. The scaling relationships are used to show how local thermal-hydraulic phenomena in each facility can be compared to each other or to expected plant behavior. The concept of an equilibrium plot is used to show how the global response of each facility can be related for a specific small break loss-of-coolant transient. Potential complications that may arise as a consequence of the facility scaling or facility limitations are enumerated. The potential use of dimensionless groupings for relating and specifying experiments is discussed. Finally, some specific experiments and conditions are proposed for the purpose of simplifying interfacility comparison of test results.

  7. Interspecific scaling patterns of talar articular surfaces within primates and their closest living relatives.

    PubMed

    Yapuncich, Gabriel S; Boyer, Doug M

    2014-02-01

    The articular facets of interosseous joints must transmit forces while maintaining relatively low stresses. To prevent overloading, joints that transmit higher forces should therefore have larger facet areas. The relative contributions of body mass and muscle-induced forces to joint stress are unclear, but generate opposing hypotheses. If mass-induced forces dominate, facet area should scale with positive allometry to body mass. Alternatively, muscle-induced forces should cause facets to scale isometrically with body mass. Within primates, both scaling patterns have been reported for articular surfaces of the femoral and humeral heads, but more distal elements are less well studied. Additionally, examination of complex articular surfaces has largely been limited to linear measurements, so that 'true area' remains poorly assessed. To re-assess these scaling relationships, we examine the relationship between body size and articular surface areas of the talus. Area measurements were taken from microCT scan-generated surfaces of all talar facets from a comprehensive sample of extant euarchontan taxa (primates, treeshrews, and colugos). Log-transformed data were regressed on literature-derived log-body mass using reduced major axis and phylogenetic least squares regressions. We examine the scaling patterns of muscle mass and physiological cross-sectional area (PCSA) to body mass, as these relationships may complicate each model. Finally, we examine the scaling pattern of hindlimb muscle PCSA to talar articular surface area, a direct test of the effect of mass-induced forces on joint surfaces. Among most groups, there is an overall trend toward positive allometry for articular surfaces. The ectal (= posterior calcaneal) facet scales with positive allometry among all groups except 'sundatherians', strepsirrhines, galagids, and lorisids. The medial tibial facet scales isometrically among all groups except lemuroids. Scaling coefficients are not correlated with sample size

  8. 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

  9. Scaling relation between earthquake magnitude and the departure time from P wave similar growth

    USGS Publications Warehouse

    Noda, Shunta; Ellsworth, William L.

    2016-01-01

    We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K-NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of departure from similarity of the absolute displacement after applying a band-pass filter, correlates with the final M in a range of 4.5 ≤ Mw ≤ 7. The scaling relation between Mw and Tdp implies that useful information on the final M can be derived while the event is still in progress because Tdp occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.

  10. Large-scale circulation departures related to wet episodes in northeast Brazil

    NASA Technical Reports Server (NTRS)

    Sikdar, D. N.; Elsner, J. B.

    1985-01-01

    Large scale circulation features are presented as related to wet spells over northeast Brazil (Nordeste) during the rainy season (March and April) of 1979. The rainy season season is devided into dry and wet periods, the FGGE and geostationary satellite data was averaged and mean and departure fields of basic variables and cloudiness were studied. Analysis of seasonal mean circulation features show: lowest sea level easterlies beneath upper level westerlies; weak meridional winds; high relative humidity over the Amazon basin and relatively dry conditions over the South Atlantic Ocean. A fluctuation was found in the large scale circulation features on time scales of a few weeks or so over Nordeste and the South Atlantic sector. Even the subtropical High SLP's have large departures during wet episodes, implying a short period oscillation in the Southern Hemisphere Hadley circulation.

  11. Large-scale circulation departures related to wet episodes in north-east Brazil

    NASA Technical Reports Server (NTRS)

    Sikdar, Dhirendra N.; Elsner, James B.

    1987-01-01

    Large scale circulation features are presented as related to wet spells over northeast Brazil (Nordeste) during the rainy season (March and April) of 1979. The rainy season is divided into dry and wet periods; the FGGE and geostationary satellite data was averaged; and mean and departure fields of basic variables and cloudiness were studied. Analysis of seasonal mean circulation features show: lowest sea level easterlies beneath upper level westerlies; weak meridional winds; high relative humidity over the Amazon basin and relatively dry conditions over the South Atlantic Ocean. A fluctuation was found in the large scale circulation features on time scales of a few weeks or so over Nordeste and the South Atlantic sector. Even the subtropical High SLPs have large departures during wet episodes, implying a short period oscillation in the Southern Hemisphere Hadley circulation.

  12. Health-related quality-of-life scales in Parkinson's disease: critique and recommendations.

    PubMed

    Martinez-Martin, Pablo; Jeukens-Visser, Martine; Lyons, Kelly E; Rodriguez-Blazquez, C; Selai, Caroline; Siderowf, Andrew; Welsh, Mickie; Poewe, Werner; Rascol, Oliver; Sampaio, Cristina; Stebbins, Glenn T; Goetz, Christopher G; Schrag, Anette

    2011-11-01

    Health-related quality of life is an important patient-reported outcome used in intervention trials and for monitoring the consequences of health status on physical, mental, and social domains. Parkinson's disease is a complex disorder that strongly affects patients' quality of life. Several health-related quality of life tools have been used in Parkinson's disease. A Movement Disorder Society Task Force was commissioned to rate the psychometric quality of available health-related quality of life scales as applied to Parkinson's disease. Following the methodology adopted by previous work of the Movement Disorder Society Task Force, a review of generic and specific health-related quality of life scales applied in studies on Parkinson's disease was completed. Considering the scales from 3 perspectives-use in Parkinson's disease, use by multiple research groups, and clinimetric properties-a final classification as "recommended," "suggested," or "listed" was applied to each reviewed instrument. Four generic scales (EuroQoL, Nottingham Health Profile, 36-Item Short-Form Health Survey, and Sickness Impact Profile) and 5 specific scales (39-Item Parkinson's Disease Questionnaire, Parkinson's Disease Questionnaire Short Form, Parkinson's Disease Quality of Life Questionnaire, Parkinson's Impact Scale, and Scales for Outcomes in Parkinson's Disease-Psychosocial) reached the level of "recommended." The 39-item Parkinson's Disease Questionnaire is the most thoroughly tested and applied questionnaire. Three other generic measures (Quality of Life Questionnaire 15D, Schedule for the Evaluation of Individual Quality of Life-Direct Weighting, and World Health Organization Quality of Life Assessment Short Version) and the specific Parkinson's Disease Quality of Life Scale are "suggested." With a little additional effort in completing the stipulated requirements, they could reach the "recommended" level. At present there is a wide variety of health-related quality of life measures

  13. Scaling the primate lateral geniculate nucleus: niche and neurodevelopment in the regulation of magnocellular and parvocellular cell number and nucleus volume.

    PubMed

    Finlay, Barbara L; Charvet, Christine J; Bastille, Isle; Cheung, Desmond T; Muniz, José Augusto P C; de Lima Silveira, Luiz Carlos

    2014-06-01

    New stereological assessments of lateral geniculate nucleus (LGN) neuron numbers and volumes in five New World primates (Cebus apella, Saguinus midas niger, Alouatta caraya, Aotus azarae, and Callicebus moloch) and compiled LGN volumes for an additional 26 mammals were analyzed for a better understanding of visual system evolution. Both the magnocellular (M)- and the parvocellular (P)-cell populations scale allometrically with brain volume in primates, P cells with a significantly higher slope such that, for every increase in M neuron number, P neuron numbers more than double (ln scale; y = 0.89x + 2.42R(2) = 0.664). In diurnal primates, the ratio of P to M cells was slightly but significantly higher than in nocturnal primates. For all mammals, including primates, LGN volume was unrelated to nocturnal or diurnal niche but showed marked differences in slope and intercept depending on taxonomic group. The allometric scaling of M and P cells can be related to the order of neurogenesis, with late-generated P cells increasing with positive allometry compared with the earlier-generated M cells. This developmental regularity links relative foveal representation to relative isocortex enlargement, which is also generated late. The small increase in the P/M cell ratio in diurnal primates may result from increased developmental neuron loss in the M-cell population as it competes for limited termination zones in primary visual cortex.

  14. Use of geology in the interpretation of core-scale relative permeability data

    SciTech Connect

    Ringrose, P.S.; Jensen, J.L.; Sorbie, K.S.

    1996-09-01

    A number of factors, such as wettability, pore-size distribution, and core-scale heterogeneity, are known to affect the measured relative permeability in core plug samples. This paper focuses on the influence of geological structure at the laminaset scale on water-oil imbibition relative permeability curves. The endpoint positions and curve shapes vary as a function of the type of internal heterogeneity, the flow rate, and the assumptions on the pore-scale petrophysics (e.g. wettability). Interaction between the capillary forces and heterogeneity can occur at the cm-dm scale, which results in widely varying two-phase flow behavior for rocks with the same single-phase permeability. The geometry of heterogeneity as expressed in standard geological descriptions (e.g., cross-laminated, ripple-laminated, plane-laminated) can be translated into features of the expected relative permeability behavior for each rock type, thus aiding the interpretation of relative permeability data. The authors illustrate how their findings can help to interpret sets of relative permeability data from the field, using some examples from the Admire sand, El Dorado Field, Kansas.

  15. The relative influence of habitat amount and configuration on genetic structure across multiple spatial scales

    PubMed Central

    Millette, Katie L; Keyghobadi, Nusha

    2015-01-01

    Despite strong interest in understanding how habitat spatial structure shapes the genetics of populations, the relative importance of habitat amount and configuration for patterns of genetic differentiation remains largely unexplored in empirical systems. In this study, we evaluate the relative influence of, and interactions among, the amount of habitat and aspects of its spatial configuration on genetic differentiation in the pitcher plant midge, Metriocnemus knabi. Larvae of this species are found exclusively within the water-filled leaves of pitcher plants (Sarracenia purpurea) in a system that is naturally patchy at multiple spatial scales (i.e., leaf, plant, cluster, peatland). Using generalized linear mixed models and multimodel inference, we estimated effects of the amount of habitat, patch size, interpatch distance, and patch isolation, measured at different spatial scales, on genetic differentiation (FST) among larval samples from leaves within plants, plants within clusters, and clusters within peatlands. Among leaves and plants, genetic differentiation appears to be driven by female oviposition behaviors and is influenced by habitat isolation at a broad (peatland) scale. Among clusters, gene flow is spatially restricted and aspects of both the amount of habitat and configuration at the focal scale are important, as is their interaction. Our results suggest that both habitat amount and configuration can be important determinants of genetic structure and that their relative influence is scale dependent. PMID:25628865

  16. The relative influence of habitat amount and configuration on genetic structure across multiple spatial scales.

    PubMed

    Millette, Katie L; Keyghobadi, Nusha

    2015-01-01

    Despite strong interest in understanding how habitat spatial structure shapes the genetics of populations, the relative importance of habitat amount and configuration for patterns of genetic differentiation remains largely unexplored in empirical systems. In this study, we evaluate the relative influence of, and interactions among, the amount of habitat and aspects of its spatial configuration on genetic differentiation in the pitcher plant midge, Metriocnemus knabi. Larvae of this species are found exclusively within the water-filled leaves of pitcher plants (Sarracenia purpurea) in a system that is naturally patchy at multiple spatial scales (i.e., leaf, plant, cluster, peatland). Using generalized linear mixed models and multimodel inference, we estimated effects of the amount of habitat, patch size, interpatch distance, and patch isolation, measured at different spatial scales, on genetic differentiation (F ST) among larval samples from leaves within plants, plants within clusters, and clusters within peatlands. Among leaves and plants, genetic differentiation appears to be driven by female oviposition behaviors and is influenced by habitat isolation at a broad (peatland) scale. Among clusters, gene flow is spatially restricted and aspects of both the amount of habitat and configuration at the focal scale are important, as is their interaction. Our results suggest that both habitat amount and configuration can be important determinants of genetic structure and that their relative influence is scale dependent.

  17. Positive Relational Management for Healthy Organizations: Psychometric Properties of a New Scale for Prevention for Workers

    PubMed Central

    Di Fabio, Annamaria

    2016-01-01

    This contribution aims at evaluating the psychometric properties of the Positive Relational Management Scale (PRMS) in a sample of 251 Italian workers. The dimensionality, reliability, and concurrent validity of the scale were investigated. Confirmatory factor analysis supported a correlated three-dimensional version of the scale, comprising Respect, Caring, and Connectedness. Latent correlations among the dimensions were moderate-to-strong (0.44–0.57), but suggestive of the multidimensionality of the scores. In addition, good internal consistency was confirmed. The concurrent validity is good as the Pearson’s correlations between PRMS and measure for social support, life satisfaction, life meaningfulness, and flourishing range from 0.39 to 0.52. The results indicate that the PRMS is a valid instrument for measuring positive relational management at work in the Italian context within a positive preventive perspective. PMID:27790163

  18. 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.

  19. Validity of the Adaptation to Age-related Vision Loss Scale in an Australian Cataract Population

    PubMed Central

    Gothwal, Vijaya K.; Wright, Thomas A.; Lamoureux, Ecosse L.; Pesudovs, Konrad

    2010-01-01

    Purpose The Adaptation to Age-related Vision Loss (AVL) scale was developed to measure the adjustment of older adults who are adapting to late-life vision loss. The purpose of this study was to assess whether the AVL scale satisfies the Rasch model in a cataract population. Methods The 24-item AVL scale (18 negatively and 6 positively coded) was mailed to 436 cataract patients for self-administration whilst they were on the waiting list for cataract surgery at the Flinders Eye Centre, Adelaide, South Australia. Rasch analysis was performed to determine whether the items were measuring a single construct (unidimensionality) as examined with fit statistics and principal components analysis (PCA) of the residuals. The ability of the scale to distinguish between the levels of adaptation of the participants (person separation) was investigated, with a value ≥2.0 established as the minimum acceptable. Results The AVL scale was unable to differentiate sufficiently between participants’ levels of adaptation, indicating poor person separation. One item did not fit the construct, causing misfit. Furthermore, the five positively worded items did not appear either to measure the same construct as other items, resulting in lack of unidimensionality evidenced by PCA. Following the deletion of these items, the AVL scale was one-dimensional but a single item continued to misfit, so it had to be deleted, resulting in an 18-item AVL scale. Even so, the discriminating abilities of the scale continued to be poor. Conclusions The AVL scale is not an appropriate measure of adaptation to vision loss in a cataract population.

  20. German National Proficiency Scales in Biology: Internal Structure, Relations to General Cognitive Abilities and Verbal Skills

    ERIC Educational Resources Information Center

    Kampa, Nele; Köller, Olaf

    2016-01-01

    National and international large-scale assessments (LSA) have a major impact on educational systems, which raises fundamental questions about the validity of the measures regarding their internal structure and their relations to relevant covariates. Given its importance, research on the validity of instruments specifically developed for LSA is…

  1. Validation of the Offending-Related Attitudes Questionnaire of CRIME-PICS II Scale (Chinese)

    ERIC Educational Resources Information Center

    Chui, Wing Hong; Wu, Joseph; Kwok, Yan Yuen; Liu, Liu

    2017-01-01

    This study examined the factor structure, reliability, and validity of the first part of the Chinese version of the CRIME-PICS II Scale, a self-administrated instrument assessing offending-related attitudes. Data were collected from three samples: male Hong Kong young offenders, female Mainland Chinese prisoners, and Hong Kong college students.…

  2. The Work-Related Quality of Life Scale for Higher Education Employees

    ERIC Educational Resources Information Center

    Edwards, Julian A.; Van Laar, Darren; Easton, Simon; Kinman, Gail

    2009-01-01

    Previous research suggests that higher education employees experience comparatively high levels of job stress. A range of instruments, both generic and job-specific, has been used to measure stressors and strains in this occupational context. The Work-related Quality of Life (WRQoL) scale is a measure designed to capture perceptions of the working…

  3. Absolute and Relative Reliability of Percentage of Syllables Stuttered and Severity Rating Scales

    ERIC Educational Resources Information Center

    Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark

    2014-01-01

    Purpose: Percentage of syllables stuttered (%SS) and severity rating (SR) scales are measures in common use to quantify stuttering severity and its changes during basic and clinical research conditions. However, their reliability has not been assessed with indices measuring both relative and absolute reliability. This study was designed to provide…

  4. Global-Scale Location and Distance Estimates: Common Representations and Strategies in Absolute and Relative Judgments

    ERIC Educational Resources Information Center

    Friedman, Alinda; Montello, Daniel R.

    2006-01-01

    The authors examined whether absolute and relative judgments about global-scale locations and distances were generated from common representations. At the end of a 10-week class on the regional geography of the United States, participants estimated the latitudes of 16 North American cities and all possible pairwise distances between them. Although…

  5. A comparison of relative toxicity rankings by some small-scale laboratory tests

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1977-01-01

    Small-scale laboratory tests for fire toxicity, suitable for use in the average laboratory hood, are needed for screening and ranking materials on the basis of relative toxicity. The performance of wool, cotton, and aromatic polyamide under several test procedures is presented.

  6. Single-field consistency relations of large scale structure part II: resummation and redshift space

    SciTech Connect

    Creminelli, Paolo; Gleyzes, Jérôme; Vernizzi, Filippo; Simonović, Marko E-mail: jerome.gleyzes@cea.fr E-mail: filippo.vernizzi@cea.fr

    2014-02-01

    We generalize the recently derived single-field consistency relations of Large Scale Structure in two directions. First, we treat the effect of the long modes (with momentum q) on the short ones (with momentum k) non-perturbatively, by writing resummed consistency relations which do not require k/q⋅δ{sub q} << 1. These relations do not make any assumptions on the short-scales physics and are extended to include (an arbitrary number of) multiple long modes, internal lines with soft momenta and soft loops. We do several checks of these relations in perturbation theory and we verify that the effect of soft modes always cancels out in equal-time correlators. Second, we write the relations directly in redshift space, without assuming the single-stream approximation: not only the long mode affects the short scales as a homogeneous gravitational field, but it also displaces them by its velocity along the line-of-sight. Redshift space consistency relations still vanish when short modes are taken at equal time: an observation of a signal in the squeezed limit would point towards multifield inflation or a violation of the equivalence principle.

  7. Allometric exponents as a tool to study the influence of climate on the trade-off between primary and secondary growth in major north-eastern American tree species

    PubMed Central

    Franceschini, T.; Martin-Ducup, O.; Schneider, R.

    2016-01-01

    Background and Aims Trees invest in both primary (e.g. height) and secondary (e.g. diameter) growth. The trade-off between these investments varies between species and changes with the tree growing environment. To better establish this trade-off, readily available allometric exponents relating height to diameter at breast height (γh,dbh) and stem volume to diameter at breast height (αv,dbh) were simultaneously studied. Methods Allometric exponents αv,dbh and γh,dbh were obtained from 8893 individual tree stem analyses from two broadleaved species (Betula papyrifera, Populus tremuloides) and four conifers (Picea glauca, Picea mariana, Pinus banksiana, Abies balsamea) in the temperate and boreal forests of the province of Quebec, Canada. αv,dbh and γh,dbh were related to tree age, stand density index (SDI), and mean temperature (TGS) and total precipitation (PGS) of the growing season. Key Results αv,dbh and γh,dbh were found to be invariant with PGS and positively related to SDI and TGS for all species except Pinus banksiana . The parameter values associated with SDI and TGS were of higher value for conifers than for broadleaved species. Conclusions This suggests that conifers and broadleaved species have different growth patterns. This could be explained by their different mode of development, the conifer species having a stronger apical dominance than broadleaved species. Such results could be further considered in allocation studies to quantify future carbon stocks in managed forests. PMID:26975315

  8. Organelle Size Scaling of the Budding Yeast Vacuole by Relative Growth and Inheritance.

    PubMed

    Chan, Yee-Hung M; Reyes, Lorena; Sohail, Saba M; Tran, Nancy K; Marshall, Wallace F

    2016-05-09

    It has long been noted that larger animals have larger organs compared to smaller animals of the same species, a phenomenon termed scaling [1]. Julian Huxley proposed an appealingly simple model of "relative growth"-in which an organ and the whole body grow with their own intrinsic rates [2]-that was invoked to explain scaling in organs from fiddler crab claws to human brains. Because organ size is regulated by complex, unpredictable pathways [3], it remains unclear whether scaling requires feedback mechanisms to regulate organ growth in response to organ or body size. The molecular pathways governing organelle biogenesis are simpler than organogenesis, and therefore organelle size scaling in the cell provides a more tractable case for testing Huxley's model. We ask the question: is it possible for organelle size scaling to arise if organelle growth is independent of organelle or cell size? Using the yeast vacuole as a model, we tested whether mutants defective in vacuole inheritance, vac8Δ and vac17Δ, tune vacuole biogenesis in response to perturbations in vacuole size. In vac8Δ/vac17Δ, vacuole scaling increases with the replicative age of the cell. Furthermore, vac8Δ/vac17Δ cells continued generating vacuole at roughly constant rates even when they had significantly larger vacuoles compared to wild-type. With support from computational modeling, these results suggest there is no feedback between vacuole biogenesis rates and vacuole or cell size. Rather, size scaling is determined by the relative growth rates of the vacuole and the cell, thus representing a cellular version of Huxley's model.

  9. Scaling Relation of Mega-fault Systems for Strong Ground Motion Prediction

    NASA Astrophysics Data System (ADS)

    Irikura, K.; Awata, Y.; Miyake, H.; Kagawa, T.; Miyakoshi, K.; Sato, T.; Dan, K.; Matsushima, S.

    2006-12-01

    We are studying scaling relations between fault length (L) and seismic moment (Mo) for mega-fault systems such as the 1906 San Francisco earthquake and the 2002 Denali earthquake. Scholz (2002) proposed an idea that the scaling relation changes from L-model to W-model for extra large earthquakes. According to the idea, Ikikura et al. (2004) proposed three-stage scaling relations between fault rupture area (S) and seismic moment; i.e., Mo is in proportion with S^{2/3} for Mo<7.5x1018Nm, S^{1/2} for Mo <7.5x1020, S for extra large earthquakes. Meanwhile, Somerville et al. (1999) proposed an uniform scaling, Mo is in proportion with S^{2/3}, even for larger earthquakes. We consider that the difference of the two scaling relations causes from their treatments of fault width (W). Irikura et al. (2004) introduces saturation of fault width considering thickness of seismogenic zone. However, fault widths are not observed values but estimated from aftershock distributions. We have to carefully evaluate S-Mo relationship considering uncertainty of fault widths. We try to estimate fault width from two empirical relationships, fault length vs. fault displacement (D) and seismic moment Mo vs fault length (L). The relationship L vs D is from certain data based on geological and geomorphological investigations. As for fault displacement, Awata (2006) proposes liner relationship between behavioral fault segment length and its maximum displacement. He also proposed saturation of fault displacement in case of mega-fault system. We here propose and demonstrate new scaling relations between fault length and seismic moment for mega-fault systems compiling past earthquake data (introducing field data about behavioral fault segments). We compare the derived fault width with carefully validated fault width from waveform and geodetic inversions to develop scaling relation for strong ground motion estimation. ACKNOWLEDGEMENT: A portion of this study was supported by the JNES research topic

  10. 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.

  11. 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.

  12. 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.

  13. UPDATED MASS SCALING RELATIONS FOR NUCLEAR STAR CLUSTERS AND A COMPARISON TO SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Scott, Nicholas; Graham, Alister W.

    2013-02-15

    We investigate whether or not nuclear star clusters and supermassive black holes (SMBHs) follow a common set of mass scaling relations with their host galaxy's properties, and hence can be considered to form a single class of central massive object (CMO). We have compiled a large sample of galaxies with measured nuclear star cluster masses and host galaxy properties from the literature and fit log-linear scaling relations. We find that nuclear star cluster mass, M {sub NC}, correlates most tightly with the host galaxy's velocity dispersion: log M {sub NC} = (2.11 {+-} 0.31)log ({sigma}/54) + (6.63 {+-} 0.09), but has a slope dramatically shallower than the relation defined by SMBHs. We find that the nuclear star cluster mass relations involving host galaxy (and spheroid) luminosity and stellar and dynamical mass, intercept with but are in general shallower than the corresponding black hole scaling relations. In particular, M {sub NC}{proportional_to}M {sup 0.55{+-}0.15} {sub Gal,dyn}; the nuclear cluster mass is not a constant fraction of its host galaxy or spheroid mass. We conclude that nuclear stellar clusters and SMBHs do not form a single family of CMOs.

  14. Application of the resource-based relative value scale system to pediatrics.

    PubMed

    Gerstle, Robert S; Molteni, Richard A; Andreae, Margie C; Bradley, Joel F; Brewer, Eileen D; Calabrese, Jamie; Krug, Steven E; Liechty, Edward A; Linzer, Jeffrey F; Pillsbury, Julia M; Tuli, Sanjeev Y

    2014-06-01

    The majority of public and private payers in the United States currently use the Medicare Resource-Based Relative Value Scale as the basis for physician payment. Many large group and academic practices have adopted this objective system of physician work to benchmark physician productivity, including using it, wholly or in part, to determine compensation. The Resource-Based Relative Value Scale survey instrument, used to value physician services, was designed primarily for procedural services, leading to current concerns that American Medical Association/Specialty Society Relative Value Scale Update Committee (RUC) surveys may undervalue nonprocedural evaluation and management services. The American Academy of Pediatrics is represented on the RUC, the committee charged with maintaining accurate physician work values across specialties and age groups. The Academy, working closely with other primary care and subspecialty societies, actively pursues a balanced RUC membership and a survey instrument that will ensure appropriate work relative value unit assignments, thereby allowing pediatricians to receive appropriate payment for their services relative to other services.

  15. Covariance in the thermal SZ-weak lensing mass scaling relation of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Shirasaki, Masato; Nagai, Daisuke; Lau, Erwin T.

    2016-08-01

    The thermal Sunyaev-Zel'dovich (tSZ) effect signal is widely recognized as a robust mass proxy of galaxy clusters with small intrinsic scatter. However, recent observational calibration of the tSZ scaling relation using weak lensing (WL) mass exhibits considerably larger scatter than the intrinsic scatter predicted from numerical simulations. This raises a question as to whether we can realize the full statistical power of ongoing and upcoming tSZ-WL observations of galaxy clusters. In this work, we investigate the origin of observed scatter in the tSZ-WL scaling relation, using mock maps of galaxy clusters extracted from cosmological hydrodynamic simulations. We show that the inferred intrinsic scatter from mock tSZ-WL analyses is considerably larger than the intrinsic scatter measured in simulations, and comparable to the scatter in the observed tSZ-WL relation. We show that this enhanced scatter originates from the combination of the projection of correlated structures along the line of sight and the uncertainty in the cluster radius associated with WL mass estimates, causing the amplitude of the scatter to depend on the covariance between tSZ and WL signals. We present a statistical model to recover the unbiased cluster scaling relation and cosmological parameter by taking into account the covariance in the tSZ-WL mass relation from multiwavelength cluster surveys.

  16. Measuring emotions during epistemic activities: the Epistemically-Related Emotion Scales.

    PubMed

    Pekrun, Reinhard; Vogl, Elisabeth; Muis, Krista R; Sinatra, Gale M

    2016-07-22

    Measurement instruments assessing multiple emotions during epistemic activities are largely lacking. We describe the construction and validation of the Epistemically-Related Emotion Scales, which measure surprise, curiosity, enjoyment, confusion, anxiety, frustration, and boredom occurring during epistemic cognitive activities. The instrument was tested in a multinational study of emotions during learning from conflicting texts (N = 438 university students from the United States, Canada, and Germany). The findings document the reliability, internal validity, and external validity of the instrument. A seven-factor model best fit the data, suggesting that epistemically-related emotions should be conceptualised in terms of discrete emotion categories, and the scales showed metric invariance across the North American and German samples. Furthermore, emotion scores changed over time as a function of conflicting task information and related significantly to perceived task value and use of cognitive and metacognitive learning strategies.

  17. Validity of DSM-IV axis V global assessment of relational functioning scale: a multimethod assessment.

    PubMed

    Stein, Michelle B; Hilsenroth, Mark; Pinsker-Aspen, Janet H; Primavera, Louis

    2009-01-01

    We investigate the convergent validity of the DSM-IV Axis V Global Assessment of Relational Functioning Scale (GARF; American Psychiatric Association, 1994). This study included 79 patients at a university-based outpatient treatment clinic. We examined clinician-rated GARF and the relationship to self-reported (Inventory of Interpersonal Problems; IIP-C; Horowitz et al. 2000) and free response themes [Social Cognition and Object Relations Scale: SCORS; Hilsenroth, Stein & Pinsker, 2004; Westen, 1995] of interpersonal functioning. Clinician ratings of the GARF scale and SCORS variables were highly reliable and internally consistent. Convergent Validity among the GARF, SCORS, and IIP scores was calculated using a Principal Components Analysis and Confirmatory Factor Analysis (CFA). Results of the Principal Components Analysis revealed that the GARF, SCORS, and IIP scores converged on a single factor, although findings of the CFA did not fully confirm the 1 factor model originally proposed. Intercorrelations among the GARF, SCORS, and IIP variables were analyzed and a pattern of significant relationships was found between the GARF and SCORS variables. This study helps support the convergent validity GARF as a relational functioning measure and is one of the first investigations to examine this scale multidimensionally.

  18. OBSERVED SCALING RELATIONS FOR STRONG LENSING CLUSTERS: CONSEQUENCES FOR COSMOLOGY AND CLUSTER ASSEMBLY

    SciTech Connect

    Comerford, Julia M.; Moustakas, Leonidas A.; Natarajan, Priyamvada

    2010-05-20

    Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, {sigma}{sub 8}, is constrained using observed clusters of galaxies, although current estimates of {sigma}{sub 8} from the scaling relations of dynamically relaxed galaxy clusters are limited by the large scatter in the observed cluster mass-temperature (M-T) relation. With a sample of eight strong lensing clusters at 0.3 < z < 0.8, we find that the observed cluster concentration-mass relation can be used to reduce the M-T scatter by a factor of 6. Typically only relaxed clusters are used to estimate {sigma}{sub 8}, but combining the cluster concentration-mass relation with the M-T relation enables the inclusion of unrelaxed clusters as well. Thus, the resultant gains in the accuracy of {sigma}{sub 8} measurements from clusters are twofold: the errors on {sigma}{sub 8} are reduced and the cluster sample size is increased. Therefore, the statistics on {sigma}{sub 8} determination from clusters are greatly improved by the inclusion of unrelaxed clusters. Exploring cluster scaling relations further, we find that the correlation between brightest cluster galaxy (BCG) luminosity and cluster mass offers insight into the assembly histories of clusters. We find preliminary evidence for a steeper BCG luminosity-cluster mass relation for strong lensing clusters than the general cluster population, hinting that strong lensing clusters may have had more active merging histories.

  19. The dependence of the mass-metallicity relation on large-scale environment

    NASA Astrophysics Data System (ADS)

    Wu, Po-Feng; Zahid, H. Jabran; Hwang, Ho Seong; Geller, Margaret J.

    2017-03-01

    We examine the relation between gas-phase oxygen abundance and stellar mass - the MZ relation - as a function of the large-scale galaxy environment parametrized by the local density. The dependence of the MZ relation on the environment is small. The metallicity where the MZ relation saturates and the slope of the MZ relation are both independent of the local density. The impact of the large-scale environment is completely parametrized by the anticorrelation between local density and the turnover stellar mass where the MZ relation begins to saturate. Analytical modelling suggests that the anticorrelation between the local density and turnover stellar mass is a consequence of a variation in the gas content of star-forming galaxies. Across ˜1 order of magnitude in local density, the gas content at a fixed stellar mass varies by ˜5 per cent. Variation of the specific star formation rate with the environment is consistent with this interpretation. At a fixed stellar mass, galaxies in low-density environments have lower metallicities because they are slightly more gas-rich than galaxies in high-density environments. Modelling the shape of the mass-metallicity relation thus provides an indirect means to probe subtle variations in the gas content of star-forming galaxies.

  20. The resource-based relative value scale and physician reimbursement policy.

    PubMed

    Laugesen, Miriam J

    2014-11-01

    Most physicians are unfamiliar with the details of the Resource-Based Relative Value Scale (RBRVS) and how changes in the RBRVS influence Medicare and private reimbursement rates. Physicians in a wide variety of settings may benefit from understanding the RBRVS, including physicians who are employees, because many organizations use relative value units as productivity measures. Despite the complexity of the RBRVS, its logic and ideal are simple: In theory, the resource usage (comprising physician work, practice expense, and liability insurance premium costs) for one service is relative to the resource usage of all others. Ensuring relativity when new services are introduced or existing services are changed is, therefore, critical. Since the inception of the RBRVS, the American Medical Association's Relative Value Scale Update Committee (RUC) has made recommendations to the Centers for Medicare & Medicaid Services on changes to relative value units. The RUC's core focus is to develop estimates of physician work, but work estimates also partly determine practice expense payments. Critics have attributed various health-care system problems, including declining and growing gaps between primary care and specialist incomes, to the RUC's role in the RBRVS update process. There are persistent concerns regarding the quality of data used in the process and the potential for services to be overvalued. The Affordable Care Act addresses some of these concerns by increasing payments to primary care physicians, requiring reevaluation of the data underlying work relative value units, and reviewing misvalued codes.

  1. Scaling relations of three-dimensional random-exchange quantum antiferromagnets

    NASA Astrophysics Data System (ADS)

    Tan, Deng-Ruei; Jiang, Fu-Jiun

    2015-11-01

    The thermal and ground state properties of a class of three-dimensional (3D) random-exchange spin-1/2 antiferromagnets are studied using first principles quantum Monte Carlo method. Our motivation is to examine whether the newly discovered universal scaling properties, which connect the Néel temperature and the staggered magnetization density, for the clean 3D quantum dimerized Heisenberg models remain valid for the random-exchange models considered here. Remarkably, similar to the clean systems, our Monte Carlo results indicate that these scaling relations also emerge for the considered models with the introduced antiferromagnetic randomness. The scope of the validity of these scaling properties for the 3D quantum antiferromagnets is investigated as well.

  2. Gauge-independent scales related to the standard model vacuum instability

    NASA Astrophysics Data System (ADS)

    Espinosa, J. R.; Garny, M.; Konstandin, T.; Riotto, A.

    2017-03-01

    The measured (central) values of the Higgs and top quark masses indicate that the standard model (SM) effective potential develops an instability at high field values. The scale of this instability, determined as the Higgs field value at which the potential drops below the electroweak minimum, is about 1 011 GeV . However, such a scale is unphysical as it is not gauge invariant and suffers from a gauge-fixing uncertainty of up to 2 orders of magnitude. Subjecting our system, the SM, to several probes of the instability (adding higher order operators to the potential, letting the vacuum decay through critical bubbles, heating up the system to very high temperature, and inflating it) and asking in each case physical questions, we are able to provide several gauge-invariant scales related with the Higgs potential instability.

  3. THE Y {sub SZ}-Y{sub X} SCALING RELATION AS DETERMINED FROM PLANCK AND CHANDRA

    SciTech Connect

    Rozo, Eduardo; More, Surhud; Vikhlinin, Alexey

    2012-11-20

    Sunyaev-Zeldovich (SZ) clusters surveys, such as Planck, the South Pole Telescope, and the Atacama Cosmology Telescope, will soon be publishing several hundred SZ-selected systems. The key ingredient required to transport the mass calibration from current X-ray-selected cluster samples to these SZ systems is the Y {sub SZ}-Y{sub X} scaling relation. We constrain the amplitude, slope, and scatter of the Y {sub SZ}-Y{sub X} scaling relation using SZ data from Planck and X-ray data from Chandra. We find a best-fit amplitude of ln (D {sup 2} {sub A} Y {sub SZ}/CY{sub X} ) = -0.202 {+-} 0.024 at the pivot point CY{sub X} = 8 Multiplication-Sign 10{sup -5} Mpc{sup 2}. This corresponds to a Y {sub SZ}/Y{sub X} ratio of 0.82 {+-} 0.024, in good agreement with X-ray expectations after including the effects of gas clumping. The slope of the relation is {alpha} = 0.916 {+-} 0.032, consistent with unity at Almost-Equal-To 2.3{sigma}. We are unable to detect intrinsic scatter, and find no evidence that the scaling relation depends on cluster dynamical state.

  4. Scaling relations of halo cores for self-interacting dark matter

    SciTech Connect

    Lin, Henry W.; Loeb, Abraham E-mail: aloeb@cfa.harvard.edu

    2016-03-01

    Using a simple analytic formalism, we demonstrate that significant dark matter self-interactions produce halo cores that obey scaling relations nearly independent of the underlying particle physics parameters such as the annihilation cross section and the mass of the dark matter particle. For dwarf galaxies, we predict that the core density ρ{sub c} and the core radius r{sub c} should obey ρ{sub c} r{sub c} ≈ 41 M{sub ⊙} pc{sup −2} with a weak mass dependence ∼ M{sup 0.2}. Remarkably, such a scaling relation has recently been empirically inferred. Scaling relations involving core mass, core radius, and core velocity dispersion are predicted and agree well with observational data. By calibrating against numerical simulations, we predict the scatter in these relations and find them to be in excellent agreement with existing data. Future observations can test our predictions for different halo masses and redshifts.

  5. Fossil group origins - VI. Global X-ray scaling relations of fossil galaxy clusters

    NASA Astrophysics Data System (ADS)

    Kundert, A.; Gastaldello, F.; D'Onghia, E.; Girardi, M.; Aguerri, J. A. L.; Barrena, R.; Corsini, E. M.; De Grandi, S.; Jiménez-Bailón, E.; Lozada-Muñoz, M.; Méndez-Abreu, J.; Sánchez-Janssen, R.; Wilcots, E.; Zarattini, S.

    2015-11-01

    We present the first pointed X-ray observations of 10 candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to r500 for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined r500 properties, we measure global temperatures in the range 2.8 ≤ TX ≤ 5.3 keV, bolometric X-ray luminosities of 0.8 × 1044 ≤ LX, bol ≤ 7.7 × 1044 erg s-1, and estimate masses, as derived from TX, of M500 ≳ 1014 M⊙. Fossil cluster scaling relations are constructed for a sample that combines our Suzaku observed fossils with fossils in the literature. Using measurements of global X-ray luminosity, temperature, optical luminosity, and velocity dispersion, scaling relations for the fossil sample are then compared with a control sample of non-fossil systems. We find the fits of our fossil cluster scaling relations are consistent with the relations for normal groups and clusters, indicating fossil clusters have global ICM X-ray properties similar to those of comparable mass non-fossil systems.

  6. Relative time scales reveal multiple origins of parallel disjunct distributions of African caecilian amphibians.

    PubMed

    Loader, Simon P; Pisani, Davide; Cotton, James A; Gower, David J; Day, Julia J; Wilkinson, Mark

    2007-10-22

    Parallel patterns of distribution in different lineages suggest a common cause. Explanations in terms of a single biogeographic event often imply contemporaneous diversifications. Phylogenies with absolute time scales provide the most obvious means of testing temporal components of biogeographic hypotheses but, in their absence, the sequence of diversification events and whether any could have been contemporaneous can be tested with relative date estimates. Tests using relative time scales have been largely overlooked, but because they do not require the calibration upon which absolute time scales depend, they make a large amount of existing molecular data of use to historical biogeography and may also be helpful when calibration is possible but uncertain. We illustrate the use of relative dating by testing the hypothesis that parallel, disjunct east/west distributions in three independent lineages of African caecilians have a common cause. We demonstrate that at least two biogeographic events are implied by molecular data. Relative dating analysis reveals the potential complexity of causes of parallel distributions and cautions against inferring common cause from common spatial patterns without considering the temporal dimension.

  7. Scaling Relations in Coronal Mass Ejections and Energetic Proton Events Associated with Solar Superflares

    NASA Astrophysics Data System (ADS)

    Takahashi, Takuya; Mizuno, Yoshiyuki; Shibata, Kazunari

    2016-12-01

    In order to discuss the potential impact of solar “superflares” on space weather, we investigated statistical relations among energetic proton peak flux with energy higher than 10 MeV (F p ), CME speed near the Sun (V CME) obtained by Solar and Heliospheric Observatory/LASCO coronagraph, and flare soft X-ray peak flux in the 1-8 Å band (F SXR) during 110 major solar proton events recorded from 1996 to 2014. The linear regression fit results in the scaling relations {V}{CME}\\propto {F}{SXR}α , {F}p\\propto {F}{SXR}β , and {F}p\\propto {V}{CME}γ with α = 0.30 ± 0.04, β = 1.19 ± 0.08, and γ = 4.35 ± 0.50, respectively. On the basis of simple physical assumptions, on the other hand, we derive scaling relations expressing CME mass (M CME), CME speed, and energetic proton flux in terms of total flare energy (E flare) as {M}{CME}\\propto {E}{flare}2/3, {V}{CME}\\propto {E}{flare}1/6, and {F}p\\propto {E}{flare}5/6\\propto {V}{CME}5, respectively. We then combine the derived scaling relations with observation and estimated the upper limit of V CME and F p to be associated with possible solar superflares.

  8. 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

  9. Scale-Free Brain Networks Based on the Event-Related Potential during Visual Spatial Attention

    NASA Astrophysics Data System (ADS)

    Li, Ling; Jin, Zhen-Lan

    2011-04-01

    The human brain is thought of as one of the most complex dynamical systems in the universe. The network view of the dynamical system has emerged since the discovery of scale-free networks. Brain functional networks, which represent functional associations among brain regions, are extracted by measuring the temporal correlations from electroencephalogram data. We measure the topological properties of the brain functional network, including degree distribution, average degree, clustering coefficient and the shortest path length, to compare the networks of multi-channel event-related potential activity between visual spatial attention and unattention conditions. It is found that the degree distribution of the brain functional networks under both the conditions is a power law distribution, which reflects a scale-free property. Moreover, the scaling exponent of the attention condition is significantly smaller than that of the unattention condition. However, the degree distribution of equivalent random networks does not follow the power law distribution. In addition, the clustering coefficient of these random networks is smaller than those of brain networks, and the shortest path length of these random networks is large and comparable with those of brain networks. Our results, typical of scale-free networks, indicate that the scaling exponent of brain activity could reflect different cognitive processes.

  10. Large Scale Water Vapor Sources Relative to the October 2000 Piedmont Flood

    NASA Technical Reports Server (NTRS)

    Turato, Barbara; Reale, Oreste; Siccardi, Franco

    2003-01-01

    Very intense mesoscale or synoptic-scale rainfall events can occasionally be observed in the Mediterranean region without any deep cyclone developing over the areas affected by precipitation. In these perplexing cases the synoptic situation can superficially look similar to cases in which very little precipitation occurs. These situations could possibly baffle the operational weather forecasters. In this article, the major precipitation event that affected Piedmont (Italy) between 13 and 16 October 2000 is investigated. This is one of the cases in which no intense cyclone was observed within the Mediterranean region at any time, only a moderate system was present, and yet exceptional rainfall and flooding occurred. The emphasis of this study is on the moisture origin and transport. Moisture and energy balances are computed on different space- and time-scales, revealing that precipitation exceeds evaporation over an area inclusive of Piedmont and the northwestern Mediterranean region, on a time-scale encompassing the event and about two weeks preceding it. This is suggestive of an important moisture contribution originating from outside the region. A synoptic and dynamic analysis is then performed to outline the potential mechanisms that could have contributed to the large-scale moisture transport. The central part of the work uses a quasi-isentropic water-vapor back trajectory technique. The moisture sources obtained by this technique are compared with the results of the balances and with the synoptic situation, to unveil possible dynamic mechanisms and physical processes involved. It is found that moisture sources on a variety of atmospheric scales contribute to this event. First, an important contribution is caused by the extratropical remnants of former tropical storm Leslie. The large-scale environment related to this system allows a significant amount of moisture to be carried towards Europe. This happens on a time- scale of about 5-15 days preceding the

  11. Axial allometry in a neutrally buoyant environment: effects of the terrestrial-aquatic transition on vertebral scaling.

    PubMed

    Jones, K E; Pierce, S E

    2016-03-01

    Ecological diversification into new environments presents new mechanical challenges for locomotion. An extreme example of this is the transition from a terrestrial to an aquatic lifestyle. Here, we examine the implications of life in a neutrally buoyant environment on adaptations of the axial skeleton to evolutionary increases in body size. On land, mammals must use their thoracolumbar vertebral column for body support against gravity and thus exhibit increasing stabilization of the trunk as body size increases. Conversely, in water, the role of the axial skeleton in body support is reduced, and, in aquatic mammals, the vertebral column functions primarily in locomotion. Therefore, we hypothesize that the allometric stabilization associated with increasing body size in terrestrial mammals will be minimized in secondarily aquatic mammals. We test this by comparing the scaling exponent (slope) of vertebral measures from 57 terrestrial species (23 felids, 34 bovids) to 23 semi-aquatic species (pinnipeds), using phylogenetically corrected regressions. Terrestrial taxa meet predictions of allometric stabilization, with posterior vertebral column (lumbar region) shortening, increased vertebral height compared to width, and shorter, more disc-shaped centra. In contrast, pinniped vertebral proportions (e.g. length, width, height) scale with isometry, and in some cases, centra even become more spool-shaped with increasing size, suggesting increased flexibility. Our results demonstrate that evolution of a secondarily aquatic lifestyle has modified the mechanical constraints associated with evolutionary increases in body size, relative to terrestrial taxa.

  12. 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.

  13. Relations between overturning length scales at the Spanish planetary boundary layer

    NASA Astrophysics Data System (ADS)

    López, Pilar; Cano, José L.

    2016-04-01

    We analyze the behavior of the maximum Thorpe displacement (dT)max and the Thorpe scale LTat the atmospheric boundary layer (ABL), extending previous research with new data and improving our studies related to the novel use of the Thorpe method applied to ABL. The maximum Thorpe displacements vary between -900 m and 950 m for the different field campaigns. The maximum Thorpe displacement is always greater under convective conditions than under stable ones, independently of its sign. The Thorpe scale LT ranges between 0.2 m and 680 m for the different data sets which cover different stratified mixing conditions (turbulence shear-driven and convective regions). The Thorpe scale does not exceed several tens of meters under stable and neutral stratification conditions related to instantaneous density gradients. In contrast, under convective conditions, Thorpe scales are relatively large, they exceed hundreds of meters which may be related to convective bursts. We analyze the relation between (dT)max and the Thorpe scale LT and we deduce that they verify a power law. We also deduce that there is a difference in exponents of the power laws for convective conditions and shear-driven conditions. These different power laws could identify overturns created under different mechanisms. References Cuxart, J., Yagüe, C., Morales, G., Terradellas, E., Orbe, J., Calvo, J., Fernández, A., Soler, M., Infante, C., Buenestado, P., Espinalt, Joergensen, H., Rees, J., Vilà, J., Redondo, J., Cantalapiedra, I. and Conangla, L.: Stable atmospheric boundary-layer experiment in Spain (Sables 98). A report, Boundary-Layer Meteorology, 96, 337-370, 2000. Dillon, T. M.: Vertical Overturns: A Comparison of Thorpe and Ozmidov Length Scales, J. Geophys. Res., 87(C12), 9601-9613, 1982. Itsweire, E. C.: Measurements of vertical overturns in stably stratified turbulent flow, Phys. Fluids, 27(4), 764-766, 1984. Kitade, Y., Matsuyama, M. and Yoshida, J.: Distribution of overturn induced by internal

  14. Action scales for quantum decoherence and their relation to structures in phase space

    SciTech Connect

    Alonso, Daniel; Brouard, S.; Palao, Jose P.; Mayato, R. Sala

    2004-05-01

    A characteristic action {delta}S is defined whose magnitude determines some properties of the expectation value of a general quantum displacement operator. These properties are related to the capability of a given environmental ''monitoring'' system to induce decoherence in quantum systems coupled to it. We show that the scale for effective decoherence is given by {delta}S{approx_equal}({Dirac_h}/2{pi}). We relate this characteristic action with a complementary quantity, {delta}Z, and analyze their connection with the main features of the pattern of structures developed by the environmental state in different phase space representations. The relevance of the {delta}S-action scale is illustrated using both a model quantum system solved numerically and a set of model quantum systems for which analytical expressions for the time-averaged expectation value of the displacement operator are obtained explicitly.

  15. Single-field consistency relations of large scale structure part III: test of the equivalence principle

    SciTech Connect

    Creminelli, Paolo; Gleyzes, Jérôme; Vernizzi, Filippo; Hui, Lam; Simonović, Marko E-mail: jerome.gleyzes@cea.fr E-mail: msimonov@sissa.it

    2014-06-01

    The recently derived consistency relations for Large Scale Structure do not hold if the Equivalence Principle (EP) is violated. We show it explicitly in a toy model with two fluids, one of which is coupled to a fifth force. We explore the constraints that galaxy surveys can set on EP violation looking at the squeezed limit of the 3-point function involving two populations of objects. We find that one can explore EP violations of order 10{sup −3}÷10{sup −4} on cosmological scales. Chameleon models are already very constrained by the requirement of screening within the Solar System and only a very tiny region of the parameter space can be explored with this method. We show that no violation of the consistency relations is expected in Galileon models.

  16. [Scale Relativity Theory in living beings morphogenesis: fratal, determinism and chance].

    PubMed

    Chaline, J

    2012-10-01

    The Scale Relativity Theory has many biological applications from linear to non-linear and, from classical mechanics to quantum mechanics. Self-similar laws have been used as model for the description of a huge number of biological systems. Theses laws may explain the origin of basal life structures. Log-periodic behaviors of acceleration or deceleration can be applied to branching macroevolution, to the time sequences of major evolutionary leaps. The existence of such a law does not mean that the role of chance in evolution is reduced, but instead that randomness and contingency may occur within a framework which may itself be structured in a partly statistical way. The scale relativity theory can open new perspectives in evolution.

  17. Galilean invariance and the consistency relation for the nonlinear squeezed bispectrum of large scale structure

    SciTech Connect

    Peloso, Marco; Pietroni, Massimo E-mail: pietroni@pd.infn.it

    2013-05-01

    We discuss the constraints imposed on the nonlinear evolution of the Large Scale Structure (LSS) of the universe by galilean invariance, the symmetry relevant on subhorizon scales. Using Ward identities associated to the invariance, we derive fully nonlinear consistency relations between statistical correlators of the density and velocity perturbations, such as the power spectrum and the bispectrum. These relations are valid up to O(f{sub NL}{sup 2}) corrections. We then show that most of the semi-analytic methods proposed so far to resum the perturbative expansion of the LSS dynamics fail to fulfill the constraints imposed by galilean invariance, and are therefore susceptible to non-physical infrared effects. Finally, we identify and discuss a nonperturbative semi-analytical scheme which is manifestly galilean invariant at any order of its expansion.

  18. Relative importance of habitat and landscape scales on butterfly communities of urbanizing areas.

    PubMed

    Lizée, Marie-Hélène; Bonardo, Rémi; Mauffrey, Jean-François; Bertaudière-Montes, Valérie; Tatoni, Thierry; Deschamps-Cottin, Magali

    2011-01-01

    Agricultural decline and urbanization entail rapid alterations of the patterns of organization of rural landscapes in Europe. The spread of the urban footprint to the adjacent countryside contributes to the development of new anthropogenic ecosystems in formerly rural hinterlands. In this study, butterflies are considered as biological indicators of these rapid environmental changes. Our purpose is to better understand changes in biodiversity related to the evolution of available habitats in a mutating landscape. In this study, we investigate butterfly communities of four land-use types (fallow lands, gardens, vineyards, woodlands) within different landscape contexts. Our results reveal that variations in structure and functional composition of these communities are related to different levels of human disturbance at both landscape scale and habitat scale.

  19. Testing the Asteroseismic Scaling Relations for Red Giants with Eclipsing Binaries Observed by Kepler

    NASA Astrophysics Data System (ADS)

    Gaulme, P.; McKeever, J.; Jackiewicz, J.; Rawls, M. L.; Corsaro, E.; Mosser, B.; Southworth, J.; Mahadevan, S.; Bender, C.; Deshpande, R.

    2016-12-01

    Given the potential of ensemble asteroseismology for understanding fundamental properties of large numbers of stars, it is critical to determine the accuracy of the scaling relations on which these measurements are based. From several powerful validation techniques, all indications so far show that stellar radius estimates from the asteroseismic scaling relations are accurate to within a few percent. Eclipsing binary systems hosting at least one star with detectable solar-like oscillations constitute the ideal test objects for validating asteroseismic radius and mass inferences. By combining radial velocity (RV) measurements and photometric time series of eclipses, it is possible to determine the masses and radii of each component of a double-lined spectroscopic binary. We report the results of a four-year RV survey performed with the échelle spectrometer of the Astrophysical Research Consortium’s 3.5 m telescope and the APOGEE spectrometer at Apache Point Observatory. We compare the masses and radii of 10 red giants (RGs) obtained by combining radial velocities and eclipse photometry with the estimates from the asteroseismic scaling relations. We find that the asteroseismic scaling relations overestimate RG radii by about 5% on average and masses by about 15% for stars at various stages of RG evolution. Systematic overestimation of mass leads to underestimation of stellar age, which can have important implications for ensemble asteroseismology used for Galactic studies. As part of a second objective, where asteroseismology is used for understanding binary systems, we confirm that oscillations of RGs in close binaries can be suppressed enough to be undetectable, a hypothesis that was proposed in a previous work.

  20. The MUSIC of galaxy clusters - II. X-ray global properties and scaling relations

    NASA Astrophysics Data System (ADS)

    Biffi, V.; Sembolini, F.; De Petris, M.; Valdarnini, R.; Yepes, G.; Gottlöber, S.

    2014-03-01

    We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) data set. We focus on a sub-sample of 179 clusters at redshift z ˜ 0.11, with 3.2 × 1014 h-1 M⊙ < Mvir < 2 × 1015 h-1 M⊙, complete in mass. We employed the X-ray photon simulator PHOX to obtain synthetic Chandra observations and derive observable-like global properties of the intracluster medium (ICM), as X-ray temperature (TX) and luminosity (LX). TX is found to slightly underestimate the true mass-weighted temperature, although tracing fairly well the cluster total mass. We also study the effects of TX on scaling relations with cluster intrinsic properties: total (M500 and gas Mg,500 mass; integrated Compton parameter (YSZ) of the Sunyaev-Zel'dovich (SZ) thermal effect; YX = Mg,500 TX. We confirm that YX is a very good mass proxy, with a scatter on M500-YX and YSZ-YX lower than 5 per cent. The study of scaling relations among X-ray, intrinsic and SZ properties indicates that simulated MUSIC clusters reasonably resemble the self-similar prediction, especially for correlations involving TX. The observational approach also allows for a more direct comparison with real clusters, from which we find deviations mainly due to the physical description of the ICM, affecting TX and, particularly, LX.

  1. Free energy of cluster formation and a new scaling relation for the nucleation rate

    SciTech Connect

    Tanaka, Kyoko K.; Tanaka, Hidekazu; Diemand, Jürg; Angélil, Raymond

    2014-05-21

    Recent very large molecular dynamics simulations of homogeneous nucleation with (1 − 8) × 10{sup 9} Lennard-Jones atoms [J. Diemand, R. Angélil, K. K. Tanaka, and H. Tanaka, J. Chem. Phys. 139, 074309 (2013)] allow us to accurately determine the formation free energy of clusters over a wide range of cluster sizes. This is now possible because such large simulations allow for very precise measurements of the cluster size distribution in the steady state nucleation regime. The peaks of the free energy curves give critical cluster sizes, which agree well with independent estimates based on the nucleation theorem. Using these results, we derive an analytical formula and a new scaling relation for nucleation rates: ln J{sup ′}/η is scaled by ln S/η, where the supersaturation ratio is S, η is the dimensionless surface energy, and J{sup ′} is a dimensionless nucleation rate. This relation can be derived using the free energy of cluster formation at equilibrium which corresponds to the surface energy required to form the vapor-liquid interface. At low temperatures (below the triple point), we find that the surface energy divided by that of the classical nucleation theory does not depend on temperature, which leads to the scaling relation and implies a constant, positive Tolman length equal to half of the mean inter-particle separation in the liquid phase.

  2. Evolution of Cluster Scaling Relations with Near-infrared and Spitzer Imaging

    NASA Astrophysics Data System (ADS)

    Svoboda, Brian E.; Arnold, R. L.; Welch, T. J.; Rines, K.; Finn, R. A.; Vikhlinin, A.

    2010-01-01

    We present scaling relations for a unique sample of 41 X-ray-selected clusters at moderate redshift (z = 0.35 -- 0.90). Chandra data of the clusters have been used to constrain dark energy (the Chandra Cluster Cosmology Project). We have deep Flamingos/ISPI Ks-band imaging from the NOAO 4m telescopes and mid-infrared IRAC imaging from Spitzer for all 41 clusters. We use these data to estimate the cluster richnesses and stellar masses. We compare these infrared properities to X-ray properties (TX, YX, M500) from Chandra data to measure the evolution of cluster scaling relations and the halo occupation function. Both semi-analytic models and simulations incorporating radiative cooling and galaxy formation overpredict the stellar masses of clusters by a factor of 2-3. Our data will help constrain models of galaxy formation and evolution in clusters. The evolution of cluster scaling relations is an important input for understanding cosmological constraints from future cluster surveys. Companion posters study the evolution of luminosity functions and star formation in these clusters.

  3. Confirmation of general relativity on large scales from weak lensing and galaxy velocities.

    PubMed

    Reyes, Reinabelle; Mandelbaum, Rachel; Seljak, Uros; Baldauf, Tobias; Gunn, James E; Lombriser, Lucas; Smith, Robert E

    2010-03-11

    Although general relativity underlies modern cosmology, its applicability on cosmological length scales has yet to be stringently tested. Such a test has recently been proposed, using a quantity, E(G), that combines measures of large-scale gravitational lensing, galaxy clustering and structure growth rate. The combination is insensitive to 'galaxy bias' (the difference between the clustering of visible galaxies and invisible dark matter) and is thus robust to the uncertainty in this parameter. Modified theories of gravity generally predict values of E(G) different from the general relativistic prediction because, in these theories, the 'gravitational slip' (the difference between the two potentials that describe perturbations in the gravitational metric) is non-zero, which leads to changes in the growth of structure and the strength of the gravitational lensing effect. Here we report that E(G) = 0.39 +/- 0.06 on length scales of tens of megaparsecs, in agreement with the general relativistic prediction of E(G) approximately 0.4. The measured value excludes a model within the tensor-vector-scalar gravity theory, which modifies both Newtonian and Einstein gravity. However, the relatively large uncertainty still permits models within f(R) theory, which is an extension of general relativity. A fivefold decrease in uncertainty is needed to rule out these models.

  4. Gravitation and Special Relativity from Compton Wave Interactions at the Planck Scale: An Algorithmic Approach

    NASA Technical Reports Server (NTRS)

    Blackwell, William C., Jr.

    2004-01-01

    In this paper space is modeled as a lattice of Compton wave oscillators (CWOs) of near- Planck size. It is shown that gravitation and special relativity emerge from the interaction between particles Compton waves. To develop this CWO model an algorithmic approach was taken, incorporating simple rules of interaction at the Planck-scale developed using well known physical laws. This technique naturally leads to Newton s law of gravitation and a new form of doubly special relativity. The model is in apparent agreement with the holographic principle, and it predicts a cutoff energy for ultrahigh-energy cosmic rays that is consistent with observational data.

  5. Disk galaxy scaling relations at intermediate redshifts. I. The Tully-Fisher and velocity-size relations

    NASA Astrophysics Data System (ADS)

    Böhm, Asmus; Ziegler, Bodo L.

    2016-07-01

    Aims: Galaxy scaling relations such as the Tully-Fisher relation (between the maximum rotation velocity Vmax and luminosity) and the velocity-size relation (between Vmax and the disk scale length) are powerful tools to quantify the evolution of disk galaxies with cosmic time. Methods: We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z ≈ 1 using the FORS instruments of the ESO Very Large Telescope. The targets were selected from the FORS Deep Field and William Herschel Deep Field. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the two-dimensional spectra. Taking into account all geometrical, observational, and instrumental effects, these rotation curves were used to derive the intrinsic Vmax. Results: Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax was reliably determined for 124 galaxies covering redshifts 0.05 < z < 0.97. This is one of the largest kinematic samples of distant disk galaxies to date. We compared this data set to the local B-band Tully-Fisher relation and the local velocity-size relation. The scatter in both scaling relations is a factor of ~2 larger at z ≈ 0.5 than at z ≈ 0. The deviations of individual distant galaxies from the local Tully-Fisher relation are systematic in the sense that the galaxies are increasingly overluminous toward higher redshifts, corresponding to an overluminosity ΔMB = -(1.2 ± 0.5) mag at z = 1. This luminosity evolution at given Vmax is probably driven by younger stellar populations of distant galaxies with respect to their local counterparts, potentially combined with modest changes in dark matter mass fractions. The analysis of the velocity-size relation reveals that disk galaxies of a given Vmax have grown in size by a factor of ~1.5 over the past ~8 Gyr, most likely through accretion of cold gas and/or small satellites

  6. Ward identities and consistency relations for the large scale structure with multiple species

    SciTech Connect

    Peloso, Marco; Pietroni, Massimo E-mail: pietroni@pd.infn.it

    2014-04-01

    We present fully nonlinear consistency relations for the squeezed bispectrum of Large Scale Structure. These relations hold when the matter component of the Universe is composed of one or more species, and generalize those obtained in [1,2] in the single species case. The multi-species relations apply to the standard dark matter + baryons scenario, as well as to the case in which some of the fields are auxiliary quantities describing a particular population, such as dark matter halos or a specific galaxy class. If a large scale velocity bias exists between the different populations new terms appear in the consistency relations with respect to the single species case. As an illustration, we discuss two physical cases in which such a velocity bias can exist: (1) a new long range scalar force in the dark matter sector (resulting in a violation of the equivalence principle in the dark matter-baryon system), and (2) the distribution of dark matter halos relative to that of the underlying dark matter field.

  7. Revisiting with Chandra the X-ray Scaling Relations of Early-Type Galaxies

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Woo

    2011-09-01

    The scaling relations of early-type galaxies are key observables which can be directly compared with theoretical models to better understand the evolution of the galaxies and their hot ISM. We revisit the scaling relations, using high spatial resolution Chandra observations of optical and X-ray selected early type galaxies, including a large fraction of gas-poor galaxies. We have accurately measured the X-ray properties of hot ISM, after carefully removing other individual emission components. In particular, we find a positive correlation between the luminosity and temperature of the hot ISM, significantly tighter than reported by earlier studies. This relation is particularly well defined in the subsample with σ>240 km/s, where it may be related to the analogous correlation found in cD galaxies and groups/clusters. However, the gas-poor galaxies with the shallowest potentials (σ < 200 km/s) also follow this relation, contrary to the expected anti-correlation in a simple outflow/wind scenario. Galaxies with intermediate values of σ instead tend to have the same kT, while Lx(gas) spans a factor of 20. We address the implications of our results in terms of theoretical predictions of the dynamical states of hot halos.

  8. Age-related alterations in the fractal scaling of cardiac interbeat interval dynamics

    NASA Technical Reports Server (NTRS)

    Iyengar, N.; Peng, C. K.; Morin, R.; Goldberger, A. L.; Lipsitz, L. A.

    1996-01-01

    We postulated that aging is associated with disruption in the fractallike long-range correlations that characterize healthy sinus rhythm cardiac interval dynamics. Ten young (21-34 yr) and 10 elderly (68-81 yr) rigorously screened healthy subjects underwent 120 min of continuous supine resting electrocardiographic recording. We analyzed the interbeat interval time series using standard time and frequency domain statistics and using a fractal measure, detrended fluctuation analysis, to quantify long-range correlation properties. In healthy young subjects, interbeat intervals demonstrated fractal scaling, with scaling exponents (alpha) from the fluctuation analysis close to a value of 1.0. In the group of healthy elderly subjects, the interbeat interval time series had two scaling regions. Over the short range, interbeat interval fluctuations resembled a random walk process (Brownian noise, alpha = 1.5), whereas over the longer range they resembled white noise (alpha = 0.5). Short (alpha s)- and long-range (alpha 1) scaling exponents were significantly different in the elderly subjects compared with young (alpha s = 1.12 +/- 0.19 vs. 0.90 +/- 0.14, respectively, P = 0.009; alpha 1 = 0.75 +/- 0.17 vs. 0.99 +/- 0.10, respectively, P = 0.002). The crossover behavior from one scaling region to another could be modeled as a first-order autoregressive process, which closely fit the data from four elderly subjects. This implies that a single characteristic time scale may be dominating heartbeat control in these subjects. The age-related loss of fractal organization in heartbeat dynamics may reflect the degradation of integrated physiological regulatory systems and may impair an individual's ability to adapt to stress.

  9. [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.

  10. 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

  11. Validation of the Comfort scale for relatives of people in critical states of health 1

    PubMed Central

    Freitas, Kátia Santana; Menezes, Igor Gomes; Mussi, Fernanda Carneiro

    2015-01-01

    Abstract Objective: this methodological study aims to present the construct validity of the Comfort scale for family members of people in a critical state of health (ECONF). Method: this is a methodological study. The sample was made up of 274 family members of adults receiving inpatient treatment in six Intensive Care Units (ICU) in the State of Bahía responded to 62 items distributed in 7 dimensions. The validation procedures adopted were based on the techniques of the Classical Test Theory. Results: the analysis of dimensionality was undertaken through principal components analysis, a scale being obtained with 55 items distributed in four factors: Safety, Support, Family member-relative interaction and Integration with oneself and the everyday. The analysis of the items' , discriminative power, undertaken by the item-total correlation-coefficient showed a good relationship of the items with their respective factors. From the ECONF's reliability test, from the analysis of internal consistency, a raised Alpha Cronbach coefficient was obtained for the 4 factors and the general measurement. Conclusion: the comfort scale presented satisfactory psychometric parameters, thus constituting the first valid instrument for evaluating the comfort of family members of people in a critical state of health. The advance made by the study lies in its theoretical framework on comfort, and provides the health team with a scale based on empirical evidence. PMID:26444168

  12. Schooling behaviour and environmental forcing in relation to anchoveta distribution: An analysis across multiple spatial scales

    NASA Astrophysics Data System (ADS)

    Bertrand, Arnaud; Gerlotto, François; Bertrand, Sophie; Gutiérrez, Mariano; Alza, Luis; Chipollini, Andres; Díaz, Erich; Espinoza, Pepe; Ledesma, Jesús; Quesquén, Roberto; Peraltilla, Salvador; Chavez, Francisco

    2008-10-01

    The Peruvian anchovy or anchoveta ( Engraulis ringens) supports the highest worldwide fishery landings and varies in space and time over many scales. Here we present the first comprehensive sub-mesocale study of anchoveta distribution in relation to the environment. During November 2004, we conducted a behavioural ecology survey off central Peru and used a series of observational and sampling tools including SST and CO 2 sensors, Niskin bottles, CTD probes, zooplankton sampling, stomach content analysis, echo-sounder, multibeam sonar, and bird observations. The sub-mesoscale survey areas were chosen from mesoscale acoustic surveys. A routine coast-wide (∼2000 km) acoustic survey performed just after the sub-mesoscale surveys, provided information at an even larger population scale. The availability of nearly concurrent sub-mesoscale, mesoscale and coast-wide information on anchoveta distribution allowed for a unique multi-scale synthesis. At the sub-mesoscale (100s m to km) physical processes (internal waves and frontogenesis) concentrated plankton into patches and determined anchoveta spatial distribution. At the mesoscale (10s km) location relative to the zone of active upwelling (and age of the upwelled water) and the depth of the oxycline had strong impacts on the anchoveta. Finally, over 100s km the size of the productive area, as defined by the upwelled cold coastal waters, was the determining factor. We propose a conceptual view of the relative importance of social behaviour and environmental (biotic and abiotic) processes on the spatial distribution of anchoveta. Our ecological space has two y-axis; one based on self-organization (social behaviour), and the other based on the environmental processes. At scales from the individual (10s cm), to the nucleus (m), social behaviour (e.g. the need to school) drives spatial organization. At scales larger than the school, environmental forces are the main driver of fish distribution. The conceptual ecosystem

  13. 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

  14. Urban energy consumption and related carbon emission estimation: a study at the sector scale

    NASA Astrophysics Data System (ADS)

    Lu, Weiwei; Chen, Chen; Su, Meirong; Chen, Bin; Cai, Yanpeng; Xing, Tao

    2013-12-01

    With rapid economic development and energy consumption growth, China has become the largest energy consumer in the world. Impelled by extensive international concern, there is an urgent need to analyze the characteristics of energy consumption and related carbon emission, with the objective of saving energy, reducing carbon emission, and lessening environmental impact. Focusing on urban ecosystems, the biggest energy consumer, a method for estimating energy consumption and related carbon emission was established at the urban sector scale in this paper. Based on data for 1996-2010, the proposed method was applied to Beijing in a case study to analyze the consumption of different energy resources (i.e., coal, oil, gas, and electricity) and related carbon emission in different sectors (i.e., agriculture, industry, construction, transportation, household, and service sectors). The results showed that coal and oil contributed most to energy consumption and carbon emission among different energy resources during the study period, while the industrial sector consumed the most energy and emitted the most carbon among different sectors. Suggestions were put forward for energy conservation and emission reduction in Beijing. The analysis of energy consumption and related carbon emission at the sector scale is helpful for practical energy saving and emission reduction in urban ecosystems.

  15. Scaling relations for galaxies of all types with CALIFA and MaNGA surveys.

    NASA Astrophysics Data System (ADS)

    Aquino-Ortíz, E.; Sánchez-Sánchez, S. F.; Valenzuela, O.; Cano-Díaz, M.; Hernández-Toledo, H.

    2016-06-01

    We used gas and stellar kinematics for the final Data Release of 667 spatially resolved galaxies publicly available from Calar Alto Legacy Integral Field Area survey (CALIFA) with the aim of study dynamical scaling relations as Tully & Fisher for rotation velocity, Faber & Jackson for velocity dispersion and also a combination of them through the S_{K} parameter defined as S_{K}^2 = KV_{rot}^2 + σ^2. We found a offset between gas and stellar kinematics in Tully & Fisher and Faber & Jackson relations, however when we used the S_{K} parameter all galaxies regardless of the morphological type lie in this M_{*} vs S_{k} scaling relation with a significant improvement compared with the M_{*} vs V_{rot} and M_{*} vs σ relations, in agreement with previous studies with SAMI survey, however the slope ant zero-point are different with them. We also explored different values of the K parameter, as well as different proxys to estimate V_{rot} in order to understand and characterize the physical source of scatter, slope and zero-point.

  16. Giant molecular cloud scaling relations: the role of the cloud definition

    NASA Astrophysics Data System (ADS)

    Khoperskov, S. A.; Vasiliev, E. O.; Ladeyschikov, D. A.; Sobolev, A. M.; Khoperskov, A. V.

    2016-01-01

    We investigate the physical properties of molecular clouds in disc galaxies with different morphologies: a galaxy without prominent structure, a spiral barred galaxy and a galaxy with flocculent structure. Our N-body/hydrodynamical simulations take into account non-equilibrium H2 and CO chemical kinetics, self-gravity, star formation and feedback processes. For the simulated galaxies, the scaling relations of giant molecular clouds, or so-called Larson's relations, are studied for two types of cloud definition (or extraction method): the first is based on total column density position-position (PP) data sets and the second is indicated by the CO (1-0) line emission used in position-position-velocity (PPV) data. We find that the cloud populations obtained using both cloud extraction methods generally have similar physical parameters, except that for the CO data the mass spectrum of clouds has a tail with low-mass objects M ˜ 103-104 M⊙. Owing toa varying column density threshold, the power-law indices in the scaling relations are significantly changed. In contrast, the relations are invariant to the CO brightness temperature threshold. Finally, we find that the mass spectra of clouds for PPV data are almost insensitive to the galactic morphology, whereas the spectra for PP data demonstrate significant variation.

  17. Weak lensing calibrated M-T scaling relation of galaxy groups in the cosmos field

    SciTech Connect

    Kettula, K.; Finoguenov, A.; Massey, R.; Rhodes, J.; Hoekstra, H.; Taylor, J. E.; Spinelli, P. F.; Tanaka, M.; Ilbert, O.; Capak, P.; McCracken, H. J.; Koekemoer, A.

    2013-11-20

    The scaling between X-ray observables and mass for galaxy clusters and groups is instrumental for cluster-based cosmology and an important probe for the thermodynamics of the intracluster gas. We calibrate a scaling relation between the weak lensing mass and X-ray spectroscopic temperature for 10 galaxy groups in the COSMOS field, combined with 55 higher-mass clusters from the literature. The COSMOS data includes Hubble Space Telescope imaging and redshift measurements of 46 source galaxies per arcminute{sup 2}, enabling us to perform unique weak lensing measurements of low-mass systems. Our sample extends the mass range of the lensing calibrated M-T relation an order of magnitude lower than any previous study, resulting in a power-law slope of 1.48{sub −0.09}{sup +0.13}. The slope is consistent with the self-similar model, predictions from simulations, and observations of clusters. However, X-ray observations relying on mass measurements derived under the assumption of hydrostatic equilibrium have indicated that masses at group scales are lower than expected. Both simulations and observations suggest that hydrostatic mass measurements can be biased low. Our external weak lensing masses provide the first observational support for hydrostatic mass bias at group level, showing an increasing bias with decreasing temperature and reaching a level of 30%-50% at 1 keV.

  18. Scaling Relations Between Mainshock Source Parameters and Aftershock Distributions for Use in Aftershock Forecasting

    NASA Astrophysics Data System (ADS)

    Donovan, J.; Jordan, T. H.

    2010-12-01

    Aftershocks are often used to delineate the mainshock rupture zone retrospectively. In aftershock forecasting on the other hand, the problem is to use mainshock rupture area to determine the aftershock zone prospectively. The procedures for this type of prediction are not as well developed and have been restricted to simple parameterizations such as the Utsu-Seki (1955) scaling relation between mainshock energy and aftershock area (Ogata and Zhueng, 2006). With a focus on improving current forecasting methods, we investigate the relationship between spatial source parameters that can be rapidly computed (spatial centroid and characteristic dimensions) and corresponding spatial measures of the aftershock distribution. For a set of about 30 large events, we either extracted source parameters from the McGuire et al (2002) finite moment tensor (FMT) catalog, or computed them from the online SRCMOD database (Mai, 2004). We identified aftershocks with windowing and scale-free methods, and computed both L1 and L2 measures of their distributions. Our comparisons produce scaling relations among the characteristic dimensions that can be used to initiate aftershock forecasts. By using rapidly-determined source parameters, we can decrease the forecasting latency and thus improve the probability gain of the forecasting methods.

  19. Relative Time-scale for Channeling Events Within Chaotic Terrains, Margaritifer Sinus, Mars

    NASA Technical Reports Server (NTRS)

    Janke, D.

    1985-01-01

    A relative time scale for ordering channel and chaos forming events was constructed for areas within the Margaritifer Sinus region of Mars. Transection and superposition relationships of channels, chaotic terrain, and the surfaces surrounding them were used to create the relative time scale; crater density studies were not used. Channels and chaos in contact with one another were treated as systems. These systems were in turn treated both separately (in order to understand internal relationships) and as members of the suite of Martian erosional forms (in order to produce a combined, master time scale). Channeling events associated with chaotic terrain development occurred over an extended geomorphic period. The channels can be divided into three convenient groups: those that pre-date intercrater plains development post-plains, pre-chasma systems; and those associated with the development of the Vallis Marineris chasmata. No correlations with cyclic climatic changes, major geologic events in other regions on Mars, or triggering phenomena (for example, specific impact events) were found.

  20. CFHTLenS: weak lensing calibrated scaling relations for low-mass clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Kettula, K.; Giodini, S.; van Uitert, E.; Hoekstra, H.; Finoguenov, A.; Lerchster, M.; Erben, T.; Heymans, C.; Hildebrandt, H.; Kitching, T. D.; Mahdavi, A.; Mellier, Y.; Miller, L.; Mirkazemi, M.; Van Waerbeke, L.; Coupon, J.; Egami, E.; Fu, L.; Hudson, M. J.; Kneib, J. P.; Kuijken, K.; McCracken, H. J.; Pereira, M. J.; Rowe, B.; Schrabback, T.; Tanaka, M.; Velander, M.

    2015-08-01

    We present weak lensing and X-ray analysis of 12 low-mass clusters from the Canada-France-Hawaii Telescope Lensing Survey and XMM-CFHTLS surveys. We combine these systems with high-mass systems from Canadian Cluster Comparison Project and low-mass systems from Cosmic Evolution Survey to obtain a sample of 70 systems, spanning over two orders of magnitude in mass. We measure core-excised LX-TX, M-LX and M-TX scaling relations and include corrections for observational biases. By providing fully bias-corrected relations, we give the current limitations for LX and TX as cluster mass proxies. We demonstrate that TX benefits from a significantly lower intrinsic scatter at fixed mass than LX. By studying the residuals of the bias-corrected relations, we show for the first time using weak lensing masses that galaxy groups seem more luminous and warmer for their mass than clusters. This implies a steepening of the M-LX and M-TX relations at low masses. We verify the inferred steepening using a different high-mass sample from the literature and show that variance between samples is the dominant effect leading to discrepant scaling relations. We divide our sample into subsamples of merging and relaxed systems, and find that mergers may have enhanced scatter in lensing measurements, most likely due to stronger triaxiality and more substructure. For the LX-TX relation, which is unaffected by lensing measurements, we find the opposite trend in scatter. We also explore the effects of X-ray cross-calibration and find that Chandra calibration leads to flatter LX-TX and M-TX relations than XMM-Newton.

  1. Optical-SZE Scaling Relations for DES Optically Selected Clusters within the SPT-SZ Survey

    SciTech Connect

    Saro, A.; et al.

    2016-05-27

    We study the Sunyaev-Zel'dovich effect (SZE) signature in South Pole Telescope (SPT) data for an ensemble of 719 optically identified galaxy clusters selected from 124.6 deg$^2$ of the Dark Energy Survey (DES) science verification data, detecting a stacked SZE signal down to richness $\\lambda\\sim20$. The SZE signature is measured using matched-filtered maps of the 2500 deg$^2$ SPT-SZ survey at the positions of the DES clusters, and the degeneracy between SZE observable and matched-filter size is broken by adopting as priors SZE and optical mass-observable relations that are either calibrated using SPT selected clusters or through the Arnaud et al. (2010, A10) X-ray analysis. We measure the SPT signal to noise $\\zeta$-$\\lambda$, relation and two integrated Compton-$y$ $Y_\\textrm{500}$-$\\lambda$ relations for the DES-selected clusters and compare these to model expectations accounting for the SZE-optical center offset distribution. For clusters with $\\lambda > 80$, the two SPT calibrated scaling relations are consistent with the measurements, while for the A10-calibrated relation the measured SZE signal is smaller by a factor of $0.61 \\pm 0.12$ compared to the prediction. For clusters at $20 < \\lambda < 80$, the measured SZE signal is smaller by a factor of $\\sim$0.20-0.80 (between 2.3 and 10~$\\sigma$ significance) compared to the prediction, with the SPT calibrated scaling relations and larger $\\lambda$ clusters showing generally better agreement. We quantify the required corrections to achieve consistency, showing that there is a richness dependent bias that can be explained by some combination of contamination of the observables and biases in the estimated masses. We discuss possible physical effects, as contamination from line-of-sight projections or from point sources, larger offsets in the SZE-optical centering or larger scatter in the $\\lambda$-mass relation at lower richnesses.

  2. Early-type galaxies in the Antlia Cluster: a deep look into scaling relations

    NASA Astrophysics Data System (ADS)

    Calderón, Juan P.; Bassino, Lilia P.; Cellone, Sergio A.; Richtler, Tom; Caso, Juan P.; Gómez, Matías

    2015-07-01

    We present the first large-scale study of the photometric and structural relations followed by early-type galaxies (ETGs) in the Antlia cluster. Antlia is the third nearest populous galaxy cluster after Fornax and Virgo (d ˜ 35 Mpc). A photographic catalogue of its galaxy content was built by Ferguson & Sandage in 1990 (FS90). Afterwards, we performed further analysis of the ETG population located at the cluster centre. Now, we extend our study covering an area four times larger, calculating new total magnitudes and colours, instead of isophotal photometry, as well as structural parameters obtained through Sérsic model fits extrapolated to infinity. This work involves a total of 177 ETGs, out of them 56 per cent have been catalogued by FS90 while the rest (77 galaxies) are newly discovered ones. Medium-resolution GEMINI and Very Large Telescope (VLT) spectra are used to confirm membership when available. Including radial velocities from the literature, 59 ETGs are confirmed as Antlia members. Antlia scaling relations mainly support the existence of unique functions (linear and curved) that join bright and dwarf ETGs, excluding compact ellipticals (cEs). Lenticular galaxies are outliers only with respect to the curved relation derived for effective surface brightness versus absolute magnitude. The small number of bright ellipticals and cEs present in Antlia, prevents us from testing if the same data can be fitted with two different linear sequences, for bright and dwarf ETGs. However, adding data from other clusters and groups, the existence of such sequences is also noticeable in the same scaling relations.

  3. INFALL REGIONS AND SCALING RELATIONS OF X-RAY SELECTED GROUPS

    SciTech Connect

    Rines, Kenneth; Diaferio, Antonaldo E-mail: diaferio@ph.unito.it

    2010-02-15

    We use the Fifth Data Release of the Sloan Digital Sky Survey (SDSS) to study X-ray-selected galaxy groups and compare their properties to clusters. We search for infall patterns around the groups and use these to measure group mass profiles to large radii. In previous work, we analyzed infall patterns for an X-ray-selected sample of 72 clusters from the ROSAT All-Sky Survey. Here, we extend this approach to a sample of systems with smaller X-ray fluxes selected from the 400 deg{sup 2} serendipitous survey of clusters and groups in ROSAT pointed observations. We identify 16 groups with SDSS DR5 spectroscopy, search for infall patterns, and compute mass profiles out to 2-6 h {sup -1} Mpc from the group centers with the caustic technique. No other mass estimation methods are currently available at such large radii for these low-mass groups, because the virial estimate requires dynamical equilibrium and the gravitational lensing signal is too weak. Despite the small masses of these groups, most display recognizable infall patterns. We use caustic and virial mass estimates to measure the scaling relations between different observables, extending these relations to smaller fluxes and luminosities than many previous surveys. Close inspection reveals that three of the groups are subclusters in the outskirts of larger clusters. A fourth group is apparently undergoing a group-group merger. These four merging groups represent the most extreme outliers in the scaling relations. Excluding these groups, we find L{sub X} {proportional_to} {sigma}{sup 3.1{+-}}{sup 1.6} {sub p}, consistent with previous determinations for both clusters and groups. Understanding cluster and group scaling relations is crucial for measuring cosmological parameters from clusters. The complex environments of our group sample reinforce the idea that great care must be taken in determining the properties of low-mass clusters and groups.

  4. Developing Interest in Art Scale and Determining the Relation between Personality Type of Teacher Candidates and Their Interest in Art

    ERIC Educational Resources Information Center

    Taskesen, Orhan

    2014-01-01

    The goal of this study is to develop a scale that measures individuals' interest in art and to test if there is a relation between this scale and personality types. For this aim, in the first stage of the study, a scale that can measure university students' interest in art is developed. Draft scale, which is made of 25 items, is conducted on 171…

  5. What Should Constitute a Health Related Quality of Life Scale for Parkinson’s Disease?

    PubMed Central

    Aggarwal, Rajeev; Goyal, Vinay; Pandey, Ravindra Mohan; Kumar, Nand; Singh, Sumit; Shukla, Garima

    2016-01-01

    Introduction Health Related Quality of Life (HRQoL) in Parkinson’s Disease (PD) lacks universally agreed definition and its components. A conceptual framework helps in understanding the essential domains and their inter-relationship while developing patient reported outcome measure. Aim To construct a conceptual framework for developing HRQoL scale in PD. Materials and Methods A panel of 7 experts extracted 6 major domains for measuring HRQoL in PD from literature review including 8 disease specific scales for PD, 2 books on quality of life, 5 websites, relevant articles; and content analysis of semi-structured interviews of stakeholders (28 persons with PD, 6 caregivers and 9 clinicians). Extracted domains were subjected to consensus of stakeholders (7 persons with PD, 7 caregivers and 7 clinicians) on 7 point Likert scale. The panel constructed a conceptual framework and a definition of HRQoL in PD in context of available guidelines for developing patient reported outcome measures. Results The extracted domains were physical, non motor symptom, psychological, family/social, finance and treatment domains. Median of all six domains on 7 point Likert scale was 7 and inter-quartile distance was <1 in consensus agreement. The conceptual framework consisted of indicator domains and causal domains. Indicator domains (physical, psychological, and social and family) estimate the influence of causal domains (motor symptoms, non motor symptoms, finance and treatment) on quality of life. The definition emphasizes upon the person’s perception of their symptoms and its impact on their lives. Conclusion This study defined and developed a conceptual framework for HRQoL scale for PD. PMID:27790491

  6. The Pressure-Activation-Stress scale in relation to ADHD and cortisol.

    PubMed

    Isaksson, J; Nilsson, K W; Lindblad, F

    2015-02-01

    The Pressure-Activation-Stress (PAS) scale is a self-report questionnaire for children concerning perceived stress. To explore behavioral and physiological correlates, we investigated if scores discriminate between a group prone to perceive high levels of stress [children with attention-deficit/hyperactivity disorder (ADHD)] and a healthy school sample, and if they are associated with diurnal cortisol levels. The PAS scale was filled in at home by children (11-17 years) with clinically confirmed ADHD (n = 102) and non-affected comparisons (n = 146). Saliva samples were collected four times during a regular school day for radioimmunoassay analysis of cortisol. Subtypes and severity of ADHD symptoms were determined using parental rating scales. Children with ADHD scored higher on the PAS scale than a school sample. The PAS scores were similar over ages in the ADHD group while they increased with age in the healthy group. Female sex was associated with higher stress in both groups but no gender interaction was found. No association was found between PAS scores and cortisol levels in neither group. Children in the ADHD group had a lower ratio of cortisol levels/perceived stress on all sampling occasions, built up both by the higher PAS scores and the lower cortisol levels in children with ADHD. The higher PAS scores in children with ADHD support the validity of the scale. The lack of association between PAS scores and diurnal cortisol levels is intriguing and illustrates the complexity of the stress concept. Stress-related fragility seems to accompany ADHD during childhood.

  7. Consistency relations for large-scale structures with primordial non-Gaussianities

    NASA Astrophysics Data System (ADS)

    Valageas, Patrick; Taruya, Atsushi; Nishimichi, Takahiro

    2017-01-01

    We investigate how the consistency relations of large-scale structures are modified when the initial density field is not Gaussian. We consider both scenarios where the primordial density field can be written as a nonlinear functional of a Gaussian field and more general scenarios where the probability distribution of the primordial density field can be expanded around the Gaussian distribution, up to all orders over δL 0. Working at linear order over the non-Gaussianity parameters fNL(n ) or Sn, we find that the consistency relations for the matter density fields are modified as they include additional contributions that involve all-order mixed linear-nonlinear correlations ⟨∏δL∏δ ⟩. We derive the conditions needed to recover the simple Gaussian form of the consistency relations. This corresponds to scenarios that become Gaussian in the squeezed limit. Our results also apply to biased tracers and velocity or momentum cross-correlations.

  8. Scaling Effects in Perovskite Ferroelectrics: Fundamental Limits and Process-Structure-Property Relations

    DOE PAGES

    Ihlefeld, Jon F.; Harris, David T.; Keech, Ryan; ...

    2016-07-05

    Ferroelectric materials are well-suited for a variety of applications because they can offer a combination of high performance and scaled integration. Examples of note include piezoelectrics to transform between electrical and mechanical energies, capacitors used to store charge, electro-optic devices, and non-volatile memory storage. Accordingly, they are widely used as sensors, actuators, energy storage, and memory components, ultrasonic devices, and in consumer electronics products. Because these functional properties arise from a non-centrosymmetric crystal structure with spontaneous strain and a permanent electric dipole, the properties depend upon physical and electrical boundary conditions, and consequently, physical dimension. The change of properties withmore » decreasing physical dimension is commonly referred to as a size effect. In thin films, size effects are widely observed, while in bulk ceramics, changes in properties from the values of large-grained specimens is most notable in samples with grain sizes below several microns. It is important to note that ferroelectricity typically persists to length scales of about 10 nm, but below this point is often absent. Despite the stability of ferroelectricity for dimensions greater than ~10 nm, the dielectric and piezoelectric coefficients of scaled ferroelectrics are suppressed relative to their bulk counterparts, in some cases by changes up to 80%. The loss of extrinsic contributions (domain and phase boundary motion) to the electromechanical response accounts for much of this suppression. In this article the current understanding of the underlying mechanisms for this behavior in perovskite ferroelectrics are reviewed. We focus on the intrinsic limits of ferroelectric response, the roles of electrical and mechanical boundary conditions, grain size and thickness effects, and extraneous effects related to processing. Ultimately, in many cases, multiple mechanisms combine to produce the observed scaling

  9. Scaling Effects in Perovskite Ferroelectrics: Fundamental Limits and Process-Structure-Property Relations

    SciTech Connect

    Ihlefeld, Jon F.; Harris, David T.; Keech, Ryan; Jones, Jacob L.; Maria, Jon-Paul; Trolier-McKinstry, Susan

    2016-07-05

    Ferroelectric materials are well-suited for a variety of applications because they can offer a combination of high performance and scaled integration. Examples of note include piezoelectrics to transform between electrical and mechanical energies, capacitors used to store charge, electro-optic devices, and non-volatile memory storage. Accordingly, they are widely used as sensors, actuators, energy storage, and memory components, ultrasonic devices, and in consumer electronics products. Because these functional properties arise from a non-centrosymmetric crystal structure with spontaneous strain and a permanent electric dipole, the properties depend upon physical and electrical boundary conditions, and consequently, physical dimension. The change of properties with decreasing physical dimension is commonly referred to as a size effect. In thin films, size effects are widely observed, while in bulk ceramics, changes in properties from the values of large-grained specimens is most notable in samples with grain sizes below several microns. It is important to note that ferroelectricity typically persists to length scales of about 10 nm, but below this point is often absent. Despite the stability of ferroelectricity for dimensions greater than ~10 nm, the dielectric and piezoelectric coefficients of scaled ferroelectrics are suppressed relative to their bulk counterparts, in some cases by changes up to 80%. The loss of extrinsic contributions (domain and phase boundary motion) to the electromechanical response accounts for much of this suppression. In this article the current understanding of the underlying mechanisms for this behavior in perovskite ferroelectrics are reviewed. We focus on the intrinsic limits of ferroelectric response, the roles of electrical and mechanical boundary conditions, grain size and thickness effects, and extraneous effects related to processing. Ultimately, in many cases, multiple mechanisms combine to produce the observed scaling effects.

  10. Scale relativity theory and integrative systems biology: 2. Macroscopic quantum-type mechanics.

    PubMed

    Nottale, Laurent; Auffray, Charles

    2008-05-01

    In these two companion papers, we provide an overview and a brief history of the multiple roots, current developments and recent advances of integrative systems biology and identify multiscale integration as its grand challenge. Then we introduce the fundamental principles and the successive steps that have been followed in the construction of the scale relativity theory, which aims at describing the effects of a non-differentiable and fractal (i.e., explicitly scale dependent) geometry of space-time. The first paper of this series was devoted, in this new framework, to the construction from first principles of scale laws of increasing complexity, and to the discussion of some tentative applications of these laws to biological systems. In this second review and perspective paper, we describe the effects induced by the internal fractal structures of trajectories on motion in standard space. Their main consequence is the transformation of classical dynamics into a generalized, quantum-like self-organized dynamics. A Schrödinger-type equation is derived as an integral of the geodesic equation in a fractal space. We then indicate how gauge fields can be constructed from a geometric re-interpretation of gauge transformations as scale transformations in fractal space-time. Finally, we introduce a new tentative development of the theory, in which quantum laws would hold also in scale space, introducing complexergy as a measure of organizational complexity. Initial possible applications of this extended framework to the processes of morphogenesis and the emergence of prokaryotic and eukaryotic cellular structures are discussed. Having founded elements of the evolutionary, developmental, biochemical and cellular theories on the first principles of scale relativity theory, we introduce proposals for the construction of an integrative theory of life and for the design and implementation of novel macroscopic quantum-type experiments and devices, and discuss their potential

  11. The Scaling Relations and Star Formation Laws of Mini-starburst Complexes

    NASA Astrophysics Data System (ADS)

    Nguyen-Luong, Quang; Nguyen, Hans V. V.; Motte, Fredérique; Schneider, Nicola; Fujii, Michiko; Louvet, Fabien; Hill, Tracey; Sanhueza, Patricio; Chibueze, James O.; Didelon, Pierre

    2016-12-01

    The scaling relations and star formation laws for molecular cloud complexes (MCCs) in the Milky Way are investigated. MCCs are mostly large (R > 50 pc), massive (˜106 {\\text{}}{M}⊙ ) gravitationally unbound cloud structures. We compare their masses {M}{gas}, mass surface densities {{{Σ }}}{M{gas}}, radii R, velocity dispersions σ, star formation rates (SFRs), and SFR densities {{{Σ }}}{SFR} with those of structures ranging from cores, clumps, and giant molecular clouds, to MCCs, and galaxies, spanning eight orders of magnitudes in size and 13 orders of magnitudes in mass. This results in the following universal relations:σ ˜ {R}0.5,{M}{gas}˜ {R}2,{{{Σ }}}{SFR}˜ {{{Σ }}}{M{gas}}1.5, {SFR}˜ {{M}{gas}}0.9, {and} {SFR}˜ {σ }2.7. Variations in the slopes and coefficients of these relations are found at individual scales, signifying different physics acting at different scales. Additionally, there are breaks at the MCC scale in the σ {--}R relation and between starburst and normal star-forming objects in the {SFR}{--}{M}{gas} and {{{Σ }}}{SFR}-{{{Σ }}}{{{M}}{gas}} relations. Therefore, we propose to use the Schmidt-Kennicutt diagram to distinguish starburst from normal star-forming structures by applying a {{{Σ }}}{M{gas}} threshold of ˜100 {\\text{}}{M}⊙ pc-2 and a {{{Σ }}}{SFR} threshold of 1 {\\text{}}{M}⊙ yr-1 kpc-2. Mini-starburst complexes are gravitationally unbound MCCs that have enhanced {{{Σ }}}{SFR} (>1 {\\text{}}{M}⊙ yr-1 kpc-2), probably caused by dynamic events such as radiation pressure, colliding flows, or spiral arm gravitational instability. Because of dynamical evolution, gravitational boundedness does not play a significant role in regulating the star formation activity of MCCs, especially the mini-starburst complexes, which leads to the dynamical formation of massive stars and clusters. We emphasize the importance of understanding mini-starbursts in investigating the physics of starburst galaxies.

  12. Cumulative relative reactivity: A concept for modeling aquifer-scale reactive transport

    NASA Astrophysics Data System (ADS)

    Loschko, Matthias; Wöhling, Thomas; Rudolph, David L.; Cirpka, Olaf A.

    2016-10-01

    We simulate aquifer-scale reactive transport using an approach based on travel times and relative reactivity. The latter quantifies the intensity of the chemical reaction relative to a reference reaction rate with identical concentrations and can be interpreted as the strength of electron-donor (or electron-acceptor) release by the matrix, scaled by a reference release. In general, the relative reactivity is a spatially variable property reflecting the geology of the formation. In the proposed approach, we track the path of individual water parcels through the aquifer and evaluate the age of the water parcels and the relative reactivity integrated along their trajectories. By switching from spatial discretization to cumulative relative reactivity, advective-reactive transport can be simulated by solving a single system of ordinary differential equations for each combination of concentrations in the inflow. We test the validity of the approach in a two-dimensional test case of steady state groundwater flow and reactive transport involving aerobic respiration and denitrification. Here we compare steady state concentration distributions of the spatially explicit virtual truth, accounting for dispersive mixing, with the approximation based on cumulative relative reactivity and show that the errors introduced by neglecting dispersive mixing are minor if the target quantities are the mass fluxes crossing a control plane or being collected by a well. We further demonstrate the efficiency of the approach in a synthetic three-dimensional case study. The proposed approach is computationally so efficient that ensemble runs to assess statistical distributions of concentration time series of reactive solutes become feasible, which is not practical with a spatially explicit model.

  13. THE SAMI GALAXY SURVEY: TOWARD A UNIFIED DYNAMICAL SCALING RELATION FOR GALAXIES OF ALL TYPES

    SciTech Connect

    Cortese, L.; Glazebrook, K.; Mould, J.; Fogarty, L. M. R.; Bland-Hawthorn, J.; Croom, S. M.; Scott, N.; Allen, J. T.; Bloom, J.; Bryant, J. J.; Ho, I.-T.; Bekki, K.; Colless, M.; Sharp, R.; Couch, W.; Goodwin, M.; Tonini, C.; Cluver, M.; Davies, R. L.; Drinkwater, M. J.; and others

    2014-11-10

    We take advantage of the first data from the Sydney-AAO Multi-object Integral field Galaxy Survey to investigate the relation between the kinematics of gas and stars, and stellar mass in a comprehensive sample of nearby galaxies. We find that all 235 objects in our sample, regardless of their morphology, lie on a tight relation linking stellar mass (M {sub *}) to internal velocity quantified by the S {sub 0.5} parameter, which combines the contribution of both dispersion (σ) and rotational velocity (V {sub rot}) to the dynamical support of a galaxy (S{sub 0.5}=√(0.5 V{sub rot}{sup 2}+σ{sup 2})). Our results are independent of the baryonic component from which σ and V {sub rot} are estimated, as the S {sub 0.5} of stars and gas agree remarkably well. This represents a significant improvement compared to the canonical M {sub *} versus V {sub rot} and M {sub *} versus σ relations. Not only is no sample pruning necessary, but also stellar and gas kinematics can be used simultaneously, as the effect of asymmetric drift is taken into account once V {sub rot} and σ are combined. Our findings illustrate how the combination of dispersion and rotational velocities for both gas and stars can provide us with a single dynamical scaling relation valid for galaxies of all morphologies across at least the stellar mass range 8.5 relation appears to be more general and at least as tight as any other dynamical scaling relation, representing a unique tool for investigating the link between galaxy kinematics and baryonic content, and a less biased comparison with theoretical models.

  14. The SAMI Galaxy Survey: Toward a Unified Dynamical Scaling Relation for Galaxies of All Types

    NASA Astrophysics Data System (ADS)

    Cortese, L.; Fogarty, L. M. R.; Ho, I.-T.; Bekki, K.; Bland-Hawthorn, J.; Colless, M.; Couch, W.; Croom, S. M.; Glazebrook, K.; Mould, J.; Scott, N.; Sharp, R.; Tonini, C.; Allen, J. T.; Bloom, J.; Bryant, J. J.; Cluver, M.; Davies, R. L.; Drinkwater, M. J.; Goodwin, M.; Green, A.; Kewley, L. J.; Kostantopoulos, I. S.; Lawrence, J. S.; Mahajan, S.; Medling, A. M.; Owers, M.; Richards, S. N.; Sweet, S. M.; Wong, O. I.

    2014-11-01

    We take advantage of the first data from the Sydney-AAO Multi-object Integral field Galaxy Survey to investigate the relation between the kinematics of gas and stars, and stellar mass in a comprehensive sample of nearby galaxies. We find that all 235 objects in our sample, regardless of their morphology, lie on a tight relation linking stellar mass (M *) to internal velocity quantified by the S 0.5 parameter, which combines the contribution of both dispersion (σ) and rotational velocity (V rot) to the dynamical support of a galaxy (S0.5=\\sqrt{0.5 V_rot2+σ 2}). Our results are independent of the baryonic component from which σ and V rot are estimated, as the S 0.5 of stars and gas agree remarkably well. This represents a significant improvement compared to the canonical M * versus V rot and M * versus σ relations. Not only is no sample pruning necessary, but also stellar and gas kinematics can be used simultaneously, as the effect of asymmetric drift is taken into account once V rot and σ are combined. Our findings illustrate how the combination of dispersion and rotational velocities for both gas and stars can provide us with a single dynamical scaling relation valid for galaxies of all morphologies across at least the stellar mass range 8.5 relation appears to be more general and at least as tight as any other dynamical scaling relation, representing a unique tool for investigating the link between galaxy kinematics and baryonic content, and a less biased comparison with theoretical models.

  15. 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).

  16. 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).

  17. Incremental Validity of the Subscales of the Emotional Regulation Related to Testing Scale for Predicting Test Anxiety

    ERIC Educational Resources Information Center

    Feldt, Ronald; Lindley, Kyla; Louison, Rebecca; Roe, Allison; Timm, Megan; Utinkova, Nikola

    2015-01-01

    The Emotional Regulation Related to Testing Scale (ERT Scale) assesses strategies students use to regulate emotion related to academic testing. It has four dimensions: Cognitive Appraising Processes (CAP), Emotion-Focusing Processes (EFP), Task-Focusing Processes (TFP), and Regaining Task-Focusing Processes (RTFP). The study examined the factor…

  18. Effects of galactic disc inclination and resolution on observed GMC properties and Larson's scaling relations

    NASA Astrophysics Data System (ADS)

    Pan, Hsi-An; Fujimoto, Yusuke; Tasker, Elizabeth J.; Rosolowsky, Erik; Colombo, Dario; Benincasa, Samantha M.; Wadsley, James

    2016-05-01

    With ALMA (Atacama Large Millimeter/submillimeter Array) making it possible to resolve giant molecular clouds (GMCs) in other galaxies, it is becoming necessary to quantify the observational bias on measured GMC properties. Using a hydrodynamical simulation of a barred spiral galaxy, we compared the physical properties of GMCs formed in position-position-position (PPP) space to the observational position-position-velocity (PPV) space. We assessed the effect of disc inclination: face-on (PPVface) and edge-on (PPVedge), and resolution: 1.5 pc versus 24 pc, on GMC properties and the further implications of using Larson's scaling relations for mass-radius and velocity dispersion-radius. The low-resolution PPV data are generated by simulating ALMA Cycle 3 observations using the CASA package. Results show that the median properties do not differ strongly between PPP and PPVface under both resolutions, but PPVedge clouds deviate from these two. The differences become magnified when switching to the lower, but more realistic resolution. The discrepancy can lead to opposite results for the virial parameter's measure of gravitational binding, and therefore the dynamical state of the clouds. The power-law indices for the two Larson's scaling relations decrease going from PPP, PPVedge to PPVface and decrease from high to low resolutions. We conclude that the relations are not entirely driven by the underlying physical origin and therefore have to be used with caution when considering the environmental dependence, dynamical state, and the extragalactic CO-to-H2 conversion factor of GMCs.

  19. The dynamical masses, densities, and star formation scaling relations of Lyα galaxies

    SciTech Connect

    Rhoads, James E.; Malhotra, Sangeeta; Richardson, Mark L. A.; McLinden, Emily M.; Finkelstein, Steven L.; Fynbo, Johan P. U.; Tilvi, Vithal S.

    2014-01-01

    We present the first dynamical mass measurements for Lyα galaxies at high redshift, based on velocity dispersion measurements from rest-frame optical emission lines and size measurements from Hubble Space Telescope imaging, for nine galaxies drawn from four surveys. We use these measurements to study Lyα galaxies in the context of galaxy scaling relations. The resulting dynamical masses range from 10{sup 9} to 10{sup 10} M {sub ☉}. We also fit stellar population models to our sample and use them to place the Lyα sample on a stellar mass versus line width relation. The Lyα galaxies generally follow the same scaling relation as star-forming galaxies at lower redshift, although, lower stellar mass fits are also acceptable in ∼1/3 of the Lyα galaxies. Using the dynamical masses as an upper limit on gas mass, we show that Lyα galaxies have unusually active star formation for their gas mass surface density. This behavior is consistent with what is observed in starburst galaxies, despite the typically smaller masses and sizes of the Lyα galaxy population. Finally, we examine the mass densities of these galaxies and show that their future evolution likely requires dissipational ('wet') merging. In short, we find that Lyα galaxies are low-mass cousins of larger starbursts.

  20. Scaling relations and the fundamental line of the local group dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Woo, Joanna; Courteau, Stéphane; Dekel, Avishai

    2008-11-01

    We study the scaling relations between global properties of dwarf galaxies in the local group. In addition to quantifying the correlations between pairs of variables, we explore the `shape' of the distribution of galaxies in log parameter space using standardized principal component analysis, the analysis is performed first in the 3D structural parameter space of stellar mass M*, internal velocity V and characteristic radius R* (or surface brightness μ*). It is then extended to a 4D space that includes a stellar population parameter such as metallicity Z or star formation rate . We find that the local group dwarfs basically define a one-parameter `fundamental line' (FL), primarily driven by stellar mass, M*. A more detailed inspection reveals differences between the star formation properties of dwarf irregulars (dI's) and dwarf ellipticals (dE's), beyond the tendency of the latter to be more massive. In particular, the metallicities of dI's are typically lower by a factor of 3 at a given M* and they grow faster with increasing M*, showing a tighter FL in the 4D space for the dE's. The structural scaling relations of dI's resemble those of the more massive spirals, but the dI's have lower star formation rates for a given M* which also grow faster with increasing M*. On the other hand, the FL of the dE's departs from the fundamental plane of bigger ellipticals. While the one-parameter nature of the FL and the associated slopes of the scaling relations are consistent with the general predictions of supernova feedback from Dekel & Woo, the differences between the FL's of the dE's and the dI's remain a challenge and should serve as a guide for the secondary physical processes responsible for these two types.

  1. X-ray Scaling Relations of SPT Selected Galaxy Clusters Observed with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bulbul, Esra; Chiu, Inon; McDonald, Michael; Bautz, Mark W.; Benson, Bradford; Bleem, Lindsey; Miller, Eric D.; Mohr, Joseph J.

    2017-01-01

    We will present results of X-ray observations of a sample of 68 South Pole Telescope selected galaxy clusters observed with XMM-Newton. Using X-ray follow-up observations with XMM-Newton, we estimate the temperature, luminosity, and mass of the intracluster medium within R500 for each cluster. From these, we constrain the Mg-Tx, Lx-Tx, and Yx-Mgas scaling relations for a sample of massive clusters at 0.1

  2. Large-scale phytogeographical patterns in eastern Asia in relation to latitudinal and climatic gradients

    USGS Publications Warehouse

    Qian, H.; Song, J.-S.; Krestov, P.; Guo, Q.; Wu, Z.; Shen, X.; Guo, X.

    2003-01-01

    This paper aims at determining how different floristic elements (e.g. cosmopolitan, tropical, and temperate) change with latitude and major climate factors, and how latitude affects the floristic relationships between East Asia and the other parts of the world. The large-scale patterns of phytogeography in East Asia are strongly related to latitude, which covaries with several climatic variables such as temperature. Evolutionary processes such as the adaptation of plants to cold climates and current and past land connections are likely responsible for the observed latitudinal patterns.

  3. The reliability of an education-related self-efficacy scale for people with psychiatric disabilities.

    PubMed

    Harris, Meredith; Gladman, Beverley; Hennessy, Nicole; Lloyd, Chris; Mowry, Bryan; Waghorn, Geoffrey

    2011-04-01

    We investigated the reliability of the Education-related Self Efficacy Scale (ESS-40), a measure of self-efficacy at a core task level designed for people with psychiatric disabilities. Sixty community residents with schizophrenia or schizoaffective disorder participated. The ESS-40 was administered twice via telephone interview. Short cycle test-retest reliability was very good for the total score and most items. The measure demonstrated signs of a coherent internal structure, adequate face validity, good client acceptability, and promising utility. The reliability evidence supports its use in community mental health services and in psychiatric rehabilitation settings. Sensitivity and predictive validity require further investigation.

  4. A conserved function of the zinc finger transcription factor Sp8/9 in allometric appendage growth in the milkweed bug Oncopeltus fasciatus.

    PubMed

    Schaeper, Nina D; Prpic, Nikola-Michael; Wimmer, Ernst A

    2009-08-01

    The genes encoding the closely related zinc finger transcription factors Buttonhead (Btd) and D-Sp1 are expressed in the developing limb primordia of Drosophila melanogaster and are required for normal growth of the legs. The D-Sp1 homolog of the red flour beetle Tribolium castaneum, Sp8 (appropriately termed Sp8/9), is also required for the proper growth of the leg segments. Here we report on the isolation and functional study of the Sp8/9 gene from the milkweed bug Oncopeltus fasciatus. We show that Sp8/9 is expressed in the developing appendages throughout development and that the downregulation of Sp8/9 via RNAi leads to antennae, rostrum, and legs with shortened and fused segments. This supports a conserved role of Sp8/9 in allometric leg segment growth. However, all leg segments including the claws are present and the expression of the leg genes Distal-less, dachshund, and homothorax are proportionally normal, thus providing no evidence for a role of Sp8/9 in appendage specification.

  5. Dynamics of the spatial scale of visual attention revealed by brain event-related potentials

    NASA Technical Reports Server (NTRS)

    Luo, Y. J.; Greenwood, P. M.; Parasuraman, R.

    2001-01-01

    The temporal dynamics of the spatial scaling of attention during visual search were examined by recording event-related potentials (ERPs). A total of 16 young participants performed a search task in which the search array was preceded by valid cues that varied in size and hence in precision of target localization. The effects of cue size on short-latency (P1 and N1) ERP components, and the time course of these effects with variation in cue-target stimulus onset asynchrony (SOA), were examined. Reaction time (RT) to discriminate a target was prolonged as cue size increased. The amplitudes of the posterior P1 and N1 components of the ERP evoked by the search array were affected in opposite ways by the size of the precue: P1 amplitude increased whereas N1 amplitude decreased as cue size increased, particularly following the shortest SOA. The results show that when top-down information about the region to be searched is less precise (larger cues), RT is slowed and the neural generators of P1 become more active, reflecting the additional computations required in changing the spatial scale of attention to the appropriate element size to facilitate target discrimination. In contrast, the decrease in N1 amplitude with cue size may reflect a broadening of the spatial gradient of attention. The results provide electrophysiological evidence that changes in the spatial scale of attention modulate neural activity in early visual cortical areas and activate at least two temporally overlapping component processes during visual search.

  6. Relation between fish communities and riparian zone conditions at two spatial scales

    USGS Publications Warehouse

    Lee, K.E.; Goldstein, R.M.; Hanson, P.E.

    2001-01-01

     The relation offish community composition to riparian cover at two spatial scales was compared at 18 streams in the agricultural Minnesota River Basin. The two spatial scales were: (1) local riparian zone (a 200 meter wide buffer extending 2 to 3 kilometers upstream of the sampling reach); and (2) the upstream riparian zone (a 200 m wide buffer on the mainstem and all perennial tributaries upstream of the sampling reach). Analysis of variance indicated that streams with wooded-local riparian zones had greater fish species richness (means = 20 and 15, respectively) and Index of Biotic Integrity (IBI) scores (means = 40 and 26, respectively) than streams with open-local riparian zones. Streams with wooded-upstream riparian zones tended (were not statistically significant) to have greater numbers of species (means = 19 and 15, respectively) and IBI scores (means = 33 and 28, respectively) than streams with open-upstream riparian zones. There was no significant interaction between the riparian zone conditions at the two scales. This study suggests that maintenance of wooded riparian cover along streams could be effective in maintaining or improving fish community composition in streams draining heavily agricultural areas.

  7. VORTICAL MOTIONS OF BARYONIC GAS IN THE COSMIC WEB: GROWTH HISTORY AND SCALING RELATION

    SciTech Connect

    Zhu, Weishan; Feng, Long-long

    2015-10-01

    The vortical motions of the baryonic gas residing in large-scale structures are investigated by cosmological hydrodynamic simulations. Proceeding in the formation of the cosmic web, the vortical motions of baryonic matter are pumped up by baroclinity in two stages, i.e., the formation of sheets and filaments. The mean curl velocities are about <1, 1–10, 10–150, and 5–50 km s{sup −1} in voids, sheets, filaments, and knots at z = 0, respectively. The scaling of the vortical velocity of gas can be well described by the She–Leveque hierarchical turbulence model in the range of l < 0.65(1.50) h{sup −1} Mpc in a simulation with a box of size 25(100) h{sup −1} Mpc. The fractal Hausdorff dimension of vortical motions, d, revealed by velocity structure functions, is ∼2.1–2.3(∼1.8–2.1). It is slightly larger than the fractal dimension of mass distribution in filaments, D{sup f} ∼ 1.9–2.2, and smaller than the fractal dimension of sheets, D{sup s} ∼ 2.4–2.7. The vortical kinetic energy of baryonic gas is mainly transported by filaments. Both scalings of mass distribution and vortical velocity increments show distinctive transitions at the turning scale of ∼0.65(1.50) h{sup −1} Mpc, which may be closely related to the characteristic radius of density filaments.

  8. THE (BLACK HOLE)-BULGE MASS SCALING RELATION AT LOW MASSES

    SciTech Connect

    Graham, Alister W.; Scott, Nicholas

    2015-01-01

    Several recent papers have reported on the occurrence of active galactic nuclei (AGNs) containing undermassive black holes relative to a linear scaling relation between black hole mass (M {sub bh}) and host spheroid stellar mass (M {sub sph,} {sub *}). However, dramatic revisions to the M {sub bh}-M {sub sph,} {sub *} and M {sub bh}-L {sub sph} relations, based on samples containing predominantly inactive galaxies, have recently identified a new steeper relation at M {sub bh} ≲ (2-10) × 10{sup 8} M {sub ☉}, roughly corresponding to M {sub sph,} {sub *} ≲ (0.3-1) × 10{sup 11} M {sub ☉}. We show that this steeper, quadratic-like M {sub bh}-M {sub sph,} {sub *} relation defined by the Sérsic galaxies, i.e., galaxies without partially depleted cores, roughly tracks the apparent offset of the AGN having 10{sup 5} ≲ M {sub bh}/M {sub ☉} ≲ 0.5 × 10{sup 8}. That is, these AGNs are not randomly offset with low black hole masses, but also follow a steeper (nonlinear) relation. As noted by Busch et al., confirmation or rejection of a possible AGN offset from the steeper M {sub bh}-M {sub sph,} {sub *} relation defined by the Sérsic galaxies will benefit from improved stellar mass-to-light ratios for the spheroids hosting these AGNs. Several implications for formation theories are noted. Furthermore, reasons for possible under- and overmassive black holes, the potential existence of intermediate mass black holes (<10{sup 5} M {sub ☉}), and the new steep (black hole)-(nuclear star cluster) relation, M{sub bh}∝M{sub nc}{sup 2.7±0.7}, are also discussed.

  9. Characterizing two-phase flow relative permeabilities in chemicalflooding using a pore-scale network model

    SciTech Connect

    Liu, Qingjie; Shen, Pingping; Wu, Yu-Shu

    2004-03-15

    A dynamic pore-scale network model is presented for investigating the effects of interfacial tension and oil-water viscosity on relative permeability during chemical flooding. This model takes into account both viscous and capillary forces in analyzing the impact of chemical properties on flow behavior or displacement configuration, as opposed to the conventional or invasion percolation algorithm which incorporates capillary pressure only. The study results indicate that both water and oil relative-permeability curves are dependent strongly on interfacial tension as well as an oil-water viscosity ratio. In particular, water and oil relative-permeability curves are both found to shift upward as interfacial tension is reduced, and they both tend to become linear versus saturation once interfacial tension is at low values. In addition, the oil-water viscosity ratio appears to have only a small effect under conditions of high interfacial tension. When the interfacial tension is low, however, water relative permeability decreases more rapidly (with the increase in the aqueous-phase viscosity) than oil relative permeability. The breakthrough saturation of the aqueous phase during chemical flooding tends to decrease with the reduction of interfacial tension and may also be affected by the oil-water viscosity ratio.

  10. Stress-related noradrenergic activity prompts large-scale neural network reconfiguration.

    PubMed

    Hermans, Erno J; van Marle, Hein J F; Ossewaarde, Lindsey; Henckens, Marloes J A G; Qin, Shaozheng; van Kesteren, Marlieke T R; Schoots, Vincent C; Cousijn, Helena; Rijpkema, Mark; Oostenveld, Robert; Fernández, Guillén

    2011-11-25

    Acute stress shifts the brain into a state that fosters rapid defense mechanisms. Stress-related neuromodulators are thought to trigger this change by altering properties of large-scale neural populations throughout the brain. We investigated this brain-state shift in humans. During exposure to a fear-related acute stressor, responsiveness and interconnectivity within a network including cortical (frontoinsular, dorsal anterior cingulate, inferotemporal, and temporoparietal) and subcortical (amygdala, thalamus, hypothalamus, and midbrain) regions increased as a function of stress response magnitudes. β-adrenergic receptor blockade, but not cortisol synthesis inhibition, diminished this increase. Thus, our findings reveal that noradrenergic activation during acute stress results in prolonged coupling within a distributed network that integrates information exchange between regions involved in autonomic-neuroendocrine control and vigilant attentional reorienting.

  11. Spectral measurements at different spatial scales in potato: relating leaf, plant and canopy nitrogen status

    NASA Astrophysics Data System (ADS)

    Jongschaap, Raymond E. E.; Booij, Remmie

    2004-09-01

    Chlorophyll contents in vegetation depend on soil nitrogen availability and on crop nitrogen uptake, which are important management factors in arable farming. Crop nitrogen uptake is important, as nitrogen is needed for chlorophyll formation, which is important for photosynthesis, i.e. the conversion of absorbed radiance into plant biomass. The objective of this study was to estimate leaf and canopy nitrogen contents by near and remote sensing observations and to link observations at leaf, plant and canopy level. A theoretical base is presented for scaling-up leaf optical properties to whole plants and crops, by linking different optical recording techniques at leaf, plant and canopy levels through the integration of vertical nitrogen distribution. Field data come from potato experiments in The Netherlands in 1997 and 1998, comprising two potato varieties: Eersteling and Bintje, receiving similar nitrogen treatments (0, 100, 200 and 300 kg N ha -1) in varying application schemes to create differences in canopy nitrogen status during the growing season. Ten standard destructive field samplings were performed to follow leaf area index and crop dry weight evolution. Samples were analysed for inorganic nitrogen and total nitrogen contents. At sampling dates, spectral measurements were taken both at leaf level and at canopy level. At leaf level, an exponential relation between SPAD-502 readings and leaf organic nitrogen contents with a high correlation factor of 0.91 was found. At canopy level, an exponential relation between canopy organic nitrogen contents and red edge position ( λrep, nm) derived from reflectance measurements was found with a good correlation of 0.82. Spectral measurements (SPAD-502) at leaf level of a few square mm were related to canopy reflectance measurements (CropScan™) of approximately 0.44 m 2. Statistical regression techniques were used to optimise theoretical vertical nitrogen profiles that allowed scaling-up leaf chlorophyll measurements

  12. Calculation of large scale relative permeabilities from stochastic properties of the permeability field and fluid properties

    SciTech Connect

    Lenormand, R.; Thiele, M.R.

    1997-08-01

    The paper describes the method and presents preliminary results for the calculation of homogenized relative permeabilities using stochastic properties of the permeability field. In heterogeneous media, the spreading of an injected fluid is mainly sue to the permeability heterogeneity and viscosity fingering. At large scale, when the heterogeneous medium is replaced by a homogeneous one, we need to introduce a homogenized (or pseudo) relative permeability to obtain the same spreading. Generally, is derived by using fine-grid numerical simulations (Kyte and Berry). However, this operation is time consuming and cannot be performed for all the meshes of the reservoir. We propose an alternate method which uses the information given by the stochastic properties of the field without any numerical simulation. The method is based on recent developments on homogenized transport equations (the {open_quotes}MHD{close_quotes} equation, Lenormand SPE 30797). The MHD equation accounts for the three basic mechanisms of spreading of the injected fluid: (1) Dispersive spreading due to small scale randomness, characterized by a macrodispersion coefficient D. (2) Convective spreading due to large scale heterogeneities (layers) characterized by a heterogeneity factor H. (3) Viscous fingering characterized by an apparent viscosity ration M. In the paper, we first derive the parameters D and H as functions of variance and correlation length of the permeability field. The results are shown to be in good agreement with fine-grid simulations. The are then derived a function of D, H and M. The main result is that this approach lead to a time dependent . Finally, the calculated are compared to the values derived by history matching using fine-grid numerical simulations.

  13. Longitudinal multigroup invariance analysis of the satisfaction with food-related life scale in university students.

    PubMed

    Schnettler, Berta; Miranda, Horacio; Miranda-Zapata, Edgardo; Salinas-Oñate, Natalia; Grunert, Klaus G; Lobos, Germán; Sepúlveda, José; Orellana, Ligia; Hueche, Clementina; Bonilla, Héctor

    2017-06-01

    This study examined longitudinal measurement invariance in the Satisfaction with Food-related Life (SWFL) scale using follow-up data from university students. We examined this measure of the SWFL in different groups of students, separated by various characteristics. Through non-probabilistic longitudinal sampling, 114 university students (65.8% female, mean age: 22.5) completed the SWFL questionnaire three times, over intervals of approximately one year. Confirmatory factor analysis was used to examine longitudinal measurement invariance. Two types of analysis were conducted: first, a longitudinal invariance by time, and second, a multigroup longitudinal invariance by sex, age, socio-economic status and place of residence during the study period. Results showed that the 3-item version of the SWFL exhibited strong longitudinal invariance (equal factor loadings and equal indicator intercepts). Longitudinal multigroup invariance analysis also showed that the 3-item version of the SWFL displays strong invariance by socio-economic status and place of residence during the study period over time. Nevertheless, it was only possible to demonstrate equivalence of the longitudinal factor structure among students of both sexes, and among those older and younger than 22 years. Generally, these findings suggest that the SWFL scale has satisfactory psychometric properties for longitudinal measurement invariance in university students with similar characteristics as the students that participated in this research. It is also possible to suggest that satisfaction with food-related life is associated with sex and age.

  14. The Concurrent Validity of Two Forms of the RAM Scale Relative to Three Criterion Measures Indicating School-Related Preferences of Community College Students.

    ERIC Educational Resources Information Center

    Wright, Claudia R.; And Others

    1984-01-01

    Two samples of 177 and 125 community college students were administered two different RAM Scale formats, then responded to three dichotomous school related criterion variables. Evidence supports the concurrent validity of RAM Scale classifications with student preferences for instructors with views similar to or different from the student's.…

  15. 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.

  16. Optical Scaling Relations of X-ray Selected Clusters at Moderate Redshift

    NASA Astrophysics Data System (ADS)

    Kloster, Dylan; Rines, K.; Svoboda, B. E.; Arnold, R. L.; Welch, T. J.; Finn, R. A.; Vikhlinin, A.

    2011-01-01

    The relation between dark matter and galaxies is a fundamental problem in astrophysics. Here, we study this relation using optical observations of an X-ray-selected sample of clusters at moderate redshift (z=0.35-0.90). We collected griz images of 30 clusters with WIYN/OPTIC to measure the bright end of the luminosity function. Our imaging extends approximately 2 magnitudes fainter than M*, thus including most of the total cluster light. We use the red sequence and statistical background subtraction to estimate the richnesses and stellar luminosities of the clusters. We measure scaling relations by comparing the optical properties to X-ray mass estimates derived from Chandra observations. At low redshift, some studies indicate that total stellar luminosity is a better predictor of cluster mass than X-ray luminosity. We test whether a similar result holds at moderate redshift. In the future, we will compare the optical and X-ray properties to virial mass estimates from optical spectroscopy and to Sunyaev-Zeldovich Effect observations. If photometric properties of clusters are good predictors of cluster mass, these relations could be applied to large surveys like SPT, Planck, DES, eROSITA, and LSST to improve constraints on the properties of dark energy.

  17. SZ/X-ray scaling relations using X-ray data and Planck Nominal maps

    NASA Astrophysics Data System (ADS)

    De Martino, I.; Atrio-Barandela, F.

    2016-09-01

    We determine the relation between the Comptonization parameter predicted using X-ray data YC, Xray and the X-ray luminosity LX, both magnitudes derived from ROSAT data, with the Comptonization parameter YC, SZ measured on Planck 2013 foreground cleaned Nominal maps. The 560 clusters of our sample includes clusters with masses M ≥ 1013 M⊙, one order of magnitude smaller than those used by the Planck Collaboration in a similar analysis. It also contains eight times more clusters in the redshift interval z ≤ 0.3. The prediction of the β = 2/3 model convolved with the Planck antenna beam agrees with the anisotropies measured in foreground cleaned Planck Nominal maps within the X-ray emitting region, confirming the results of an earlier analysis. The universal pressure profile overestimates the signal by a 15-21 per cent depending on the angular aperture. We show that the discrepancy is not due to the presence of cool-core systems but it is an indication of a brake in the LX - M relation towards low mass systems. We show that relation of the Comptonization parameter averaged over the region that emits 99 per cent of the X-ray flux and and the X-ray luminosity is consistent with the predictions of the self-similar model. We confirm previous findings that the scaling relations studied here do not evolve with redshift within the range probed by our catalogue.

  18. Extended general relativity: Large-scale antigravity and short-scale gravity with ω=-1 from five-dimensional vacuum

    NASA Astrophysics Data System (ADS)

    Madriz Aguilar, José Edgar; Bellini, Mauricio

    2009-08-01

    Considering a five-dimensional (5D) Riemannian spacetime with a particular stationary Ricci-flat metric, we obtain in the framework of the induced matter theory an effective 4D static and spherically symmetric metric which give us ordinary gravitational solutions on small (planetary and astrophysical) scales, but repulsive (anti gravitational) forces on very large (cosmological) scales with ω=-1. Our approach is an unified manner to describe dark energy, dark matter and ordinary matter. We illustrate the theory with two examples, the solar system and the great attractor. From the geometrical point of view, these results follow from the assumption that exists a confining force that make possible that test particles move on a given 4D hypersurface.

  19. 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.

  20. Testing fault displacement-length scaling relations through analogue modeling in an extensional setting

    NASA Astrophysics Data System (ADS)

    Bonini, L.; Basili, R.; Burrato, P.; Kastelic, V.; Toscani, G.; Seno, S.; Valensise, G.

    2013-12-01

    The scaling relation between displacement and length of faults plays a crucial role in understanding the growth history of individual faults and their possible linkage and reactivation in future ruptures. Displacement-length relations are commonly based on empirical data. The measurement of fault geometric properties, however, is generally affected by large scattering due not only to intrinsic difficulties of making observations in natural cases (outcrop availability, seismic profiles), but also to the variety of geological factors that may affect the rupture patterns. These can be the interaction between the present-day tectonic regime and an inherited structural fabric, or that between a master fault at depth and shallow structural features. As an alternative to field observations, analogue modeling provides an opportunity to investigate the faulting processes in a controlled environment. During the last decade, the ability of scaled models to properly reproduce such geological processes has greatly improved thanks to the introduction of new materials (e.g. wet kaolin) suitable for reproducing brittle deformation in the upper crust and hi-tech monitoring systems (e.g. laser scanner, particle image velocimetry) with the ability of capturing structural details and performing accurate measurements. We use a dedicated apparatus with such properties to gain insights on the evolution of extensional faults through a suite of experiments which includes (a) setups in homogeneous material to test our ability in meeting general criteria related with fault displacement-length parameters; and (b) increasing complexities attained by inserting various pre-existing fault patterns to analyze how shallow mechanical discontinuities affect our ability to characterize a major fault at depth. Our results show that pre-existing faults can either halt or favor fault development and growth depending on their location/orientation with respect to the applied stress field and suggest the

  1. The extra-galactic Cepheid distance scale from LMC and Galactic period-luminosity relations

    NASA Astrophysics Data System (ADS)

    Kanbur, S. M.; Ngeow, C.; Nikolaev, S.; Tanvir, N. R.; Hendry, M. A.

    2003-12-01

    In this paper, we recalibrate the Cepheid distance to some nearby galaxies observed by the HST Key Project and the Sandage-Tammann-Saha group. We use much of the Key Project methodology in our analysis but apply new techniques, based on Fourier methods to estimate the mean of a sparsely sampled Cepheid light curve, to published extra-galactic Cepheid data. We also apply different calibrating PL relations to estimate Cepheid distances, and investigate the sensitivity of the distance moduli to the adopted calibrating PL relation. We re-determine the OGLE LMC PL relations using a more conservative approach and also study the effect of using Galactic PL relations on the distance scale. For the Key Project galaxies after accounting for charge transfer effects, we find good agreement with an average discrepancy of -0.002 and 0.075 mag when using the LMC and Galaxy, respectively, as a calibrating PL relation. For NGC 4258 which has a geometric distance of 29.28 mag, we find a distance modulus of 29.44+/-0.06(random) mag, after correcting for metallicity. In addition we have calculated the Cepheid distance to 8 galaxies observed by the Sandage-Tammann-Saha group and find shorter distance moduli by -0.178 mag (mainly due to the use of different LMC PL relations) and -0.108 mag on average again when using the LMC and Galaxy, respectively, as a calibrating PL relation. However care must be taken to extrapolate these changed distances to changes in the resulting values of the Hubble constant because STS also use distances to NGC 3368 and 4414 and because STS calibration of SN Ia is often decoupled from the distance to the host galaxy through their use of differential extinction arguments. We also calculate the distance to all these galaxies using PL relations at maximum light and find very good agreement with mean light PL distances. However, after correcting for metallicity effects, the difference between the distance moduli obtained using the two sets of calibrating PL

  2. Investigation of Absolute and Relative Scaling Conceptions of Students in Introductory College Chemistry Courses

    ERIC Educational Resources Information Center

    Gerlach, Karrie; Trate, Jaclyn; Blecking, Anja; Geissinger, Peter; Murphy, Kristen

    2014-01-01

    Scale as a theme in science instruction is not a new idea. As early as the mid-1980s, scale was identified as an important component of a student's overall science literacy. However, the study of scale and the scale literacy of students in varying levels of education have received less attention than other science-literacy components. Foremost…

  3. Communicating Climate Uncertainties: Challenges and Opportunities Related to Spatial Scales, Extreme Events, and the Warming 'Hiatus'

    NASA Astrophysics Data System (ADS)

    Casola, J. H.; Huber, D.

    2013-12-01

    Many media, academic, government, and advocacy organizations have achieved sophistication in developing effective messages based on scientific information, and can quickly translate salient aspects of emerging climate research and evolving observations. However, there are several ways in which valid messages can be misconstrued by decision makers, leading them to inaccurate conclusions about the risks associated with climate impacts. Three cases will be discussed: 1) Issues of spatial scale in interpreting climate observations: Local climate observations may contradict summary statements about the effects of climate change on larger regional or global spatial scales. Effectively addressing these differences often requires communicators to understand local and regional climate drivers, and the distinction between a 'signal' associated with climate change and local climate 'noise.' Hydrological statistics in Missouri and California are shown to illustrate this case. 2) Issues of complexity related to extreme events: Climate change is typically invoked following a wide range of damaging meteorological events (e.g., heat waves, landfalling hurricanes, tornadoes), regardless of the strength of the relationship between anthropogenic climate change and the frequency or severity of that type of event. Examples are drawn from media coverage of several recent events, contrasting useful and potentially confusing word choices and frames. 3) Issues revolving around climate sensitivity: The so-called 'pause' or 'hiatus' in global warming has reverberated strongly through political and business discussions of climate change. Addressing the recent slowdown in warming yields an important opportunity to raise climate literacy in these communities. Attempts to use recent observations as a wedge between climate 'believers' and 'deniers' is likely to be counterproductive. Examples are drawn from Congressional testimony and media stories. All three cases illustrate ways that decision

  4. First order phase transformations: scaling relations for grain self-correlation functions

    SciTech Connect

    Axe, J.D.; Shapiro, S.M.; Yamada, Y.; Hamaya, N.

    1985-06-01

    At high pressure many alkali halides transform from the NaCl (B1) structure to the CsCl (B2) structure. We have recently studied this transformation in polycrystalline RbI, which transforms at a critical pressure, P/sub c/ = 3.5 kbar. By observing the time development of the neutron diffraction pattern after sudden increase of hydrostatic pressure from P

    P/sub c/ we directly deduced X(t), the fraction of the sample converted from metastable to stable phase, as a function of time. We showed that X(t) taken at different P could be approximately scaled onto a universal growth curve by introducing an adjustable characteristic time tau(P) for each curve. The success of the Kolmogorov in fitting X(t) suggests that comparisons of model predictions with other experimental observables be made on the system. For example, by a trivial (in principle) extension of the neutron diffraction techniques described above, one might determine the broadening of the powder diffraction peaks due to finite grain size as a function of time throughout growth. This particle size broadening is related by Fourier transformation to the grain autocorrelation function, G/sub s/(r,t), which measures the ensemble average of the overlap of grains with themselves upon translation of the grain pattern by an amount r. We present some results of a study of the scaling properties of G/sub s/(r,t) for the Kolmogorov model for d=1 and d=2. Although the model is highly idealized, it is perhaps the simplest conceivable one which obeys correlation function scaling in early stages of growth and undergoes nontrivial saturation due to volume fraction effects in the late stages. 4 refs., 6 figs.

  5. Analysis of environmental issues related to small-scale hydroelectric development. III. Water level fluctuation

    SciTech Connect

    Hildebrand, S.G.

    1980-10-01

    Potential environmental impacts in reservoirs and downstream river reaches below dams that may be caused by the water level fluctuation resulting from development and operation of small scale (under 25MW) hydroelectric projects are identified. The impacts discussed will be of potential concern at only those small-scale hydroelectric projects that are operated in a store and release (peaking) mode. Potential impacts on physical and chemical characteristics in reservoirs resulting from water level fluctuation include resuspension and redistribution of bank and bed sediment; leaching of soluble organic matter from sediment in the littoral zone; and changes in water quality resulting from changes in sediment and nutrient trap efficiency. Potential impacts on reservoir biota as a result of water level fluctuation include habitat destruction and the resulting partial or total loss of aquatic species; changes in habitat quality, which result in reduced standing crop and production of aquatic biota; and possible shifts in species diversity. The potential physical effects of water level fluctuation on downstream systems below dams are streambed and bank erosion and water quality problems related to resuspension and redistribution of these materials. Potential biological impacts of water level fluctuation on downstream systems below dams result from changes in current velocity, habitat reduction, and alteration in food supply. These alterations, either singly or in combination, can adversely affect aquatic populations below dams. The nature and potential significance of adverse impacts resulting from water level fluctuation are discussed. Recommendations for site-specific evaluation of water level fluctuation at small-scale hydroelectric projects are presented.

  6. Relation between volatility correlations in financial markets and Omori processes occurring on all scales

    NASA Astrophysics Data System (ADS)

    Weber, Philipp; Wang, Fengzhong; Vodenska-Chitkushev, Irena; Havlin, Shlomo; Stanley, H. Eugene

    2007-07-01

    We analyze the memory in volatility by studying volatility return intervals, defined as the time between two consecutive fluctuations larger than a given threshold, in time periods following stock market crashes. Such an aftercrash period is characterized by the Omori law, which describes the decay in the rate of aftershocks of a given size with time t by a power law with exponent close to 1. A shock followed by such a power law decay in the rate is here called Omori process. We find self-similar features in the volatility. Specifically, within the aftercrash period there are smaller shocks that themselves constitute Omori processes on smaller scales, similar to the Omori process after the large crash. We call these smaller shocks subcrashes, which are followed by their own aftershocks. We also show that the Omori law holds not only after significant market crashes as shown by Lillo and Mantegna [Phys. Rev. E 68, 016119 (2003)], but also after “intermediate shocks.” By appropriate detrending we remove the influence of the crashes and subcrashes from the data, and find that this procedure significantly reduces the memory in the records. Moreover, when studying long-term correlated fractional Brownian motion and autoregressive fractionally integrated moving average artificial models for volatilities, we find Omori-type behavior after high volatilities. Thus, our results support the hypothesis that the memory in the volatility is related to the Omori processes present on different time scales.

  7. Predicting Anxiety Diagnoses and Severity with the CBCL-A: Improvement Relative to Other CBCL Scales?

    PubMed Central

    Read, Kendra L.; Settipani, Cara A.; Peterman, Jeremy; Kendall, Philip C.; Compton, Scott; Piacentini, John; McCracken, James; Bergman, Lindsey; Walkup, John; Sakolsky, Dara; Birmaher, Boris; Albano, Anne Marie; Rynn, Moira; Ginsburg, Golda; Keeton, Courtney; Gosch, Elizabeth; Suveg, Cynthia; Sherrill, Joel; March, John

    2014-01-01

    The Child Behavior Checklist (CBCL) is a widely used parent-report of child and adolescent behavior. We examined the ability of the CBCL-A scale, a previously published subset of CBCL items, to predict the presence of generalized anxiety disorder (GAD), separation anxiety disorder (SAD), and social phobia (SoP), as well as anxiety severity, among 488 youth randomized in the Child Anxiety Multimodal Study (CAMS). We predicted that the CBCL-A’s unique inclusion of items related to somatic symptoms would better identify anxiety disorder and severity than other CBCL scales, given that somatic complaints are often key features of anxiety among youth. Results support the use of the anxiety-based CBCL subscales as first-line screeners for generally elevated symptoms of anxiety, rather than tools to identify specific anxiety disorders. Although somatic symptoms are often reported and included in diagnostic criteria for certain anxiety disorders (e.g., SAD, GAD), the unique combination of somatic and non-somatic symptoms for the CBCL-A subscale did not increase its ability to consistently predict the presence of specific anxiety disorders. PMID:26257470

  8. Distribution and density of moose in relation to landscape characteristics: Effects of scale

    USGS Publications Warehouse

    Maier, J.A.K.; Ver Hoef, J.M.; McGuire, A.D.; Bowyer, R.T.; Saperstein, L.; Maier, H.A.

    2005-01-01

    We analyzed the relation between early winter distribution and density of female moose (Alces alces L.) and habitat heterogeneity in interior Alaska. We tested for effects of vegetation type, topography, distance to rivers and towns, occurrence and timing of fire, and landscape metrics. A spatial linear model was used to analyze effects of independent variables organized at multiple scales. Because densities of moose vary widely as a result of differences in management and other factors, a spatial response surface of the log of moose density was fit to remove large-scale effects. The analysis revealed that the densest populations of moose occurred closer to towns, at moderate elevations, near rivers, and in areas where fire occurred between 11 and 30 years ago. Furthermore, moose tended to occur in areas with large compact patches of varied habitat and avoided variable terrain and nonvegetated areas. Relationships of most variables with moose density occurred at or below 34 km2, suggesting that moose respond to environmental variables within a few kilometres of their location. The spatial model of density of moose developed in this study represents an important application for effective monitoring and management of moose in the boreal forest. ?? 2005 NRC.

  9. Snake scales, partial exposure, and the Snake Detection Theory: A human event-related potentials study

    PubMed Central

    Van Strien, Jan W.; Isbell, Lynne A.

    2017-01-01

    Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225–300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature. PMID:28387376

  10. Predicting Anxiety Diagnoses and Severity with the CBCL-A: Improvement Relative to Other CBCL Scales?

    PubMed

    Read, Kendra L; Settipani, Cara A; Peterman, Jeremy; Kendall, Philip C; Compton, Scott; Piacentini, John; McCracken, James; Bergman, Lindsey; Walkup, John; Sakolsky, Dara; Birmaher, Boris; Albano, Anne Marie; Rynn, Moira; Ginsburg, Golda; Keeton, Courtney; Gosch, Elizabeth; Suveg, Cynthia; Sherrill, Joel; March, John

    2015-03-01

    The Child Behavior Checklist (CBCL) is a widely used parent-report of child and adolescent behavior. We examined the ability of the CBCL-A scale, a previously published subset of CBCL items, to predict the presence of generalized anxiety disorder (GAD), separation anxiety disorder (SAD), and social phobia (SoP), as well as anxiety severity, among 488 youth randomized in the Child Anxiety Multimodal Study (CAMS). We predicted that the CBCL-A's unique inclusion of items related to somatic symptoms would better identify anxiety disorder and severity than other CBCL scales, given that somatic complaints are often key features of anxiety among youth. Results support the use of the anxiety-based CBCL subscales as first-line screeners for generally elevated symptoms of anxiety, rather than tools to identify specific anxiety disorders. Although somatic symptoms are often reported and included in diagnostic criteria for certain anxiety disorders (e.g., SAD, GAD), the unique combination of somatic and non-somatic symptoms for the CBCL-A subscale did not increase its ability to consistently predict the presence of specific anxiety disorders.

  11. A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation

    NASA Astrophysics Data System (ADS)

    Pascucci, Ilaria; SLICK, EOS

    2017-01-01

    The disk mass is among the most important input parameter of planet formation models as it determines the number and masses of the planets that can form. I will present an ALMA 887 micron survey of the disk population around objects from 2 to 0.03Msun in the nearby 2 Myr-old Chamaeleon I star-forming region. Assuming isothermal and optically thin emission, we convert the 887 micron flux densities into dust disk masses (Mdust) and show that the Mdust-Mstar scaling relation is steeper than linear. By re-analyzing all millimeter data available for nearby regions in a self-consistent way, we find that the 1-3 Myr-old regions of Taurus, Lupus, and Chamaeleon I share the same Mdust-Mstar relation, while the 10 Myr-old Upper Sco association has an even steeper relation. Theoretical models of grain growth, drift, and fragmentation reproduce this trend and suggest that disks are in the fragmentation-limited regime. In this regime millimeter grains will be located closer in around lower-mass stars, a prediction that can be tested with deeper and higher spatial resolution ALMA observations.

  12. Genetic mechanisms control the linear scaling between related cortical primary and higher order sensory areas

    PubMed Central

    Zembrzycki, Andreas; Stocker, Adam M; Leingärtner, Axel; Sahara, Setsuko; Chou, Shen-Ju; Kalatsky, Valery; May, Scott R; Stryker, Michael P; O'Leary, Dennis DM

    2015-01-01

    In mammals, the neocortical layout consists of few modality-specific primary sensory areas and a multitude of higher order ones. Abnormal layout of cortical areas may disrupt sensory function and behavior. Developmental genetic mechanisms specify primary areas, but mechanisms influencing higher order area properties are unknown. By exploiting gain-of and loss-of function mouse models of the transcription factor Emx2, we have generated bi-directional changes in primary visual cortex size in vivo and have used it as a model to show a novel and prominent function for genetic mechanisms regulating primary visual area size and also proportionally dictating the sizes of surrounding higher order visual areas. This finding redefines the role for intrinsic genetic mechanisms to concomitantly specify and scale primary and related higher order sensory areas in a linear fashion. DOI: http://dx.doi.org/10.7554/eLife.11416.001 PMID:26705332

  13. To address surface reaction network complexity using scaling relations machine learning and DFT calculations.

    PubMed

    Ulissi, Zachary W; Medford, Andrew J; Bligaard, Thomas; Nørskov, Jens K

    2017-03-06

    Surface reaction networks involving hydrocarbons exhibit enormous complexity with thousands of species and reactions for all but the very simplest of chemistries. We present a framework for optimization under uncertainty for heterogeneous catalysis reaction networks using surrogate models that are trained on the fly. The surrogate model is constructed by teaching a Gaussian process adsorption energies based on group additivity fingerprints, combined with transition-state scaling relations and a simple classifier for determining the rate-limiting step. The surrogate model is iteratively used to predict the most important reaction step to be calculated explicitly with computationally demanding electronic structure theory. Applying these methods to the reaction of syngas on rhodium(111), we identify the most likely reaction mechanism. Propagating uncertainty throughout this process yields the likelihood that the final mechanism is complete given measurements on only a subset of the entire network and uncertainty in the underlying density functional theory calculations.

  14. To address surface reaction network complexity using scaling relations machine learning and DFT calculations

    PubMed Central

    Ulissi, Zachary W.; Medford, Andrew J.; Bligaard, Thomas; Nørskov, Jens K.

    2017-01-01

    Surface reaction networks involving hydrocarbons exhibit enormous complexity with thousands of species and reactions for all but the very simplest of chemistries. We present a framework for optimization under uncertainty for heterogeneous catalysis reaction networks using surrogate models that are trained on the fly. The surrogate model is constructed by teaching a Gaussian process adsorption energies based on group additivity fingerprints, combined with transition-state scaling relations and a simple classifier for determining the rate-limiting step. The surrogate model is iteratively used to predict the most important reaction step to be calculated explicitly with computationally demanding electronic structure theory. Applying these methods to the reaction of syngas on rhodium(111), we identify the most likely reaction mechanism. Propagating uncertainty throughout this process yields the likelihood that the final mechanism is complete given measurements on only a subset of the entire network and uncertainty in the underlying density functional theory calculations. PMID:28262694

  15. To address surface reaction network complexity using scaling relations machine learning and DFT calculations

    NASA Astrophysics Data System (ADS)

    Ulissi, Zachary W.; Medford, Andrew J.; Bligaard, Thomas; Nørskov, Jens K.

    2017-03-01

    Surface reaction networks involving hydrocarbons exhibit enormous complexity with thousands of species and reactions for all but the very simplest of chemistries. We present a framework for optimization under uncertainty for heterogeneous catalysis reaction networks using surrogate models that are trained on the fly. The surrogate model is constructed by teaching a Gaussian process adsorption energies based on group additivity fingerprints, combined with transition-state scaling relations and a simple classifier for determining the rate-limiting step. The surrogate model is iteratively used to predict the most important reaction step to be calculated explicitly with computationally demanding electronic structure theory. Applying these methods to the reaction of syngas on rhodium(111), we identify the most likely reaction mechanism. Propagating uncertainty throughout this process yields the likelihood that the final mechanism is complete given measurements on only a subset of the entire network and uncertainty in the underlying density functional theory calculations.

  16. Photosynthesis and stomatal conductance related to reflectance on the canopy scale

    NASA Technical Reports Server (NTRS)

    Verma, S. B.; Sellers, P. J.; Walthall, C. L.; Hall, F. G.; Kim, J.; Goetz, S. J.

    1993-01-01

    Field measurements of carbon dioxide and water vapor fluxes were analyzed in conjunction with reflectances obtained from a helicopter-mounted Modular Multiband Radiometer at a grassland study site during the First International Satellite Land Surface Climatology Project Field Experiment. These measurements are representative of the canopy scale and were made over a range of meteorological and soil moisture conditions during different stages in the annual life cycle of the prairie vegetation, and thus provide a good basis for investigating hpotheses/relationships potentially useful in remote sensing applications. We tested the hypothesis (Sellers, 1987) that the simple ratio vegetation index should be near-linearly related to the derivatives of the unstressed canopy stomatal conductance and the unstressed canopy photosynthesis with respect to photosynthetically active radiation. Even though there is some scatter in our data, the results seem to support this hypothesis.

  17. The Challenge of Electrochemical Ammonia Synthesis: A New Perspective on the Role of Nitrogen Scaling Relations.

    PubMed

    Montoya, Joseph H; Tsai, Charlie; Vojvodic, Aleksandra; Nørskov, Jens K

    2015-07-08

    The electrochemical production of NH3 under ambient conditions represents an attractive prospect for sustainable agriculture, but electrocatalysts that selectively reduce N2 to NH3 remain elusive. In this work, we present insights from DFT calculations that describe limitations on the low-temperature electrocatalytic production of NH3 from N2 . In particular, we highlight the linear scaling relations of the adsorption energies of intermediates that can be used to model the overpotential requirements in this process. By using a two-variable description of the theoretical overpotential, we identify fundamental limitations on N2 reduction analogous to those present in processes such as oxygen evolution. Using these trends, we propose new strategies for catalyst design that may help guide the search for an electrocatalyst that can achieve selective N2 reduction.

  18. Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

    NASA Technical Reports Server (NTRS)

    Squires, K. C.; Squires, N. K.; Hillyard, S. A.

    1974-01-01

    Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

  19. Cosmology and astrophysics from relaxed galaxy clusters - III. Thermodynamic profiles and scaling relations

    NASA Astrophysics Data System (ADS)

    Mantz, A. B.; Allen, S. W.; Morris, R. G.; Schmidt, R. W.

    2016-03-01

    This is the third in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Our sample comprises 40 clusters identified as being dynamically relaxed and hot (i.e. massive) in Papers I and II of this series. Here we consider the thermodynamics of the intracluster medium, in particular the profiles of density, temperature and related quantities, as well as integrated measurements of gas mass, average temperature, total luminosity and centre-excluded luminosity. We fit power-law scaling relations of each of these quantities as a function of redshift and cluster mass, which can be measured precisely and with minimal bias for these relaxed clusters using hydrostatic arguments. For the thermodynamic profiles, we jointly model the density and temperature and their intrinsic scatter as a function of radius, thus also capturing the behaviour of the gas pressure and entropy. For the integrated quantities, we also jointly fit a multidimensional intrinsic covariance. Our results reinforce the view that simple hydrodynamical models provide a good description of relaxed clusters outside their centres, but that additional heating and cooling processes are important in the inner regions (radii r ≲ 0.5 r2500 ≈ 0.15 r500). The thermodynamic profiles remain regular, with small intrinsic scatter, down to the smallest radii where deprojection is straightforward (˜20 kpc); within this radius, even the most relaxed systems show clear departures from spherical symmetry. Our results suggest that heating and cooling are continuously regulated in a tight feedback loop, allowing the cluster atmosphere to remain stratified on these scales.

  20. Multi-scale Geological Outcrop Visualisation: Using Gigapan and Photosynth in Fieldwork-related Geology Teaching

    NASA Astrophysics Data System (ADS)

    Stimpson, Ian; Gertisser, Ralf; Montenari, Michael; O'Driscoll, Brian

    2010-05-01

    An increasing proportion of geology (and other fieldwork-related discipline) students are mobility impaired. This is partially due to the widening access agenda and the acceptance of increased numbers of students with severe medical disabilities. In the UK, the expectation of "The Special Educational Needs and Disabilities Act (2001)" (SENDA) and "The Higher Education Quality Assurance Agency" (QAA) is that institutions should, wherever possible, provide alternative experiences where comparable opportunities are available which satisfy the learning outcomes. In order to provide this alternative experience, the ways in which students observe and learn from geology in the field need to be resembled closely by, for example, viewing outcrops at different scales and from different perspectives. Whilst a series of still images at different distances could be taken, students need to be able to decide where to look in detail and 'move around' the outcrop. The Gigapan project is a website and supporting software that allows high-resolution megapixel photographic images to be combined to make gigapixel panoramas which can then be explored at many scales by zooming and panning. Photosynth is a similar project where a number of different digital photographs are combined into a 3D model in which the user can move around. Here, we show examples of both projects, which have been successfully implemented in geology teaching related to a residential undergraduate field course to classic geological areas in Pembrokeshire, South Wales. In addition to providing an alternative learning experience for mobility-impaired students on the fieldtrip, these resources could also be used for non-impaired students where circumstances such as bad weather prevents the whole cohort from visiting a key exposure on a field course. They would also allow a 'virtual' visit of exposures that are inaccessible and may be a useful learning tool for preparing students for a forthcoming field course.

  1. Effect of Items Direction (Positive or Negative) on the Factorial Construction and Criterion Related Validity in Likert Scale

    ERIC Educational Resources Information Center

    Naji Qasem, Mamun Ali; Ahmad Gul, Showkeen Bilal

    2014-01-01

    The study was conducted to know the effect of items direction (positive or negative) on the factorial construction and criterion related validity in Likert scale. The descriptive survey research method was used for the study and the sample consisted of 510 undergraduate students selected by used random sampling technique. A scale developed by…

  2. RELATION OF LANDSCAPE-SCALE ENVIRONMENTAL CHARACTERISTICS TO FISH ASSEMBLAGES IN THE UPPER FRENCH BROAD RIVER BASIN, NORTH CAROLINA

    EPA Science Inventory

    Fish assemblages at 16 sites in the upper French Broad river basin in North Carolina were related to environmental characteristics at the landscape scale, the scale at which management activities and decisions are most likely to occur. Indirect gradient analysis and subsequent re...

  3. Exploring Physicians' Dissatisfaction and Work-Related Stress: Development of the PhyDis Scale

    PubMed Central

    Pedrazza, Monica; Berlanda, Sabrina; Trifiletti, Elena; Bressan, Franco

    2016-01-01

    Research, all over the world, is starting to recognize the potential impact of physicians' dissatisfaction and burnout on their productivity, that is, on their intent to leave the job, on their work ability, on the amount of sick leave days, on their intent to continue practicing, and last but not least, on the quality of the services provided, which is an essential part of the general medical care system. It was interest of the provincial medical board's ethical committee to acquire information about physician's work-related stress and dissatisfaction. The research group was committed to define the indicators of dissatisfaction and work-related stressors. Focus groups were carried out, 21 stressful experience's indicators were identified; we developed an online questionnaire to assess the amount of perceived stress relating to each indicator at work (3070 physicians were contacted by e-mail); quantitative and qualitative data analysis were carried out. The grounded theory perspective was applied in order to assure the most reliable procedure to investigate the concepts' structure of “work-related stress.” We tested the five dimensions' model of the stressful experience with a confirmatory factor analysis: Personal Costs; Decline in Public Image and Role Uncertainty; Physician's Responsibility toward hopelessly ill Patients; Relationship with Staff and Colleagues; Bureaucracy. We split the sample according to attachment style (secure and insecure -anxious and avoidant-). Results show the complex representation of physicians' dissatisfaction at work also with references to the variable of individual difference of attachment security/insecurity. The discriminant validity of the scale was tested. The original contribution of this paper lies on the one hand in the qualitative in depth inductive analysis of physicians' dissatisfaction starting from physicians' perception, on the other hand, it represents the first attempt to analyze the physicians' dissatisfaction

  4. Exploring Physicians' Dissatisfaction and Work-Related Stress: Development of the PhyDis Scale.

    PubMed

    Pedrazza, Monica; Berlanda, Sabrina; Trifiletti, Elena; Bressan, Franco

    2016-01-01

    Research, all over the world, is starting to recognize the potential impact of physicians' dissatisfaction and burnout on their productivity, that is, on their intent to leave the job, on their work ability, on the amount of sick leave days, on their intent to continue practicing, and last but not least, on the quality of the services provided, which is an essential part of the general medical care system. It was interest of the provincial medical board's ethical committee to acquire information about physician's work-related stress and dissatisfaction. The research group was committed to define the indicators of dissatisfaction and work-related stressors. Focus groups were carried out, 21 stressful experience's indicators were identified; we developed an online questionnaire to assess the amount of perceived stress relating to each indicator at work (3070 physicians were contacted by e-mail); quantitative and qualitative data analysis were carried out. The grounded theory perspective was applied in order to assure the most reliable procedure to investigate the concepts' structure of "work-related stress." We tested the five dimensions' model of the stressful experience with a confirmatory factor analysis: Personal Costs; Decline in Public Image and Role Uncertainty; Physician's Responsibility toward hopelessly ill Patients; Relationship with Staff and Colleagues; Bureaucracy. We split the sample according to attachment style (secure and insecure -anxious and avoidant-). Results show the complex representation of physicians' dissatisfaction at work also with references to the variable of individual difference of attachment security/insecurity. The discriminant validity of the scale was tested. The original contribution of this paper lies on the one hand in the qualitative in depth inductive analysis of physicians' dissatisfaction starting from physicians' perception, on the other hand, it represents the first attempt to analyze the physicians' dissatisfaction with

  5. Large-scale variation in boreal and temperate forest carbon turnover rate related to climate

    NASA Astrophysics Data System (ADS)

    Thurner, Martin; Beer, Christian; Carvalhais, Nuno; Forkel, Matthias; Santoro, Maurizio; Tum, Markus; Schmullius, Christiane

    2016-05-01

    Vegetation carbon turnover processes in forest ecosystems and their dominant drivers are far from being understood at a broader scale. Many of these turnover processes act on long timescales and include a lateral dimension and thus can hardly be investigated by plot-level studies alone. Making use of remote sensing-based products of net primary production (NPP) and biomass, here we show that spatial gradients of carbon turnover rate (k) in Northern Hemisphere boreal and temperate forests are explained by different climate-related processes depending on the ecosystem. k is related to frost damage effects and the trade-off between growth and frost adaptation in boreal forests, while drought stress and climate effects on insects and pathogens can explain an elevated k in temperate forests. By identifying relevant processes underlying broadscale patterns in k, we provide the basis for a detailed exploration of these mechanisms in field studies, and ultimately the improvement of their representations in global vegetation models (GVMs).

  6. THE SCALING RELATIONS AND THE FUNDAMENTAL PLANE FOR RADIO HALOS AND RELICS OF GALAXY CLUSTERS

    SciTech Connect

    Yuan, Z. S.; Han, J. L.; Wen, Z. L.

    2015-11-01

    Diffuse radio emission in galaxy clusters is known to be related to cluster mass and cluster dynamical state. We collect the observed fluxes of radio halos, relics, and mini-halos for a sample of galaxy clusters from the literature, and calculate their radio powers. We then obtain the values of cluster mass or mass proxies from previous observations, and also obtain the various dynamical parameters of these galaxy clusters from optical and X-ray data. The radio powers of relics, halos, and mini-halos are correlated with the cluster masses or mass proxies, as found by previous authors, while the correlations concerning giant radio halos are in general the strongest. We found that the inclusion of dynamical parameters as the third dimension can significantly reduce the data scatter for the scaling relations, especially for radio halos. We therefore conclude that the substructures in X-ray images of galaxy clusters and the irregular distributions of optical brightness of member galaxies can be used to quantitatively characterize the shock waves and turbulence in the intracluster medium responsible for re-accelerating particles to generate the observed diffuse radio emission. The power of radio halos and relics is correlated with cluster mass proxies and dynamical parameters in the form of a fundamental plane.

  7. Aging on a different scale – chronological versus pathology-related aging

    PubMed Central

    Melis, Joost P.M.; Jonker, Martijs J.; Vijg, Jan; Hoeijmakers, Jan H.J.; Breit, Timo M.; van Steeg, Harry

    2013-01-01

    In the next decades the elderly population will increase dramatically, demanding appropriate solutions in health care and aging research focusing on healthy aging to prevent high burdens and costs in health care. For this, research targeting tissue-specific and individual aging is paramount to make the necessary progression in aging research. In a recently published study we have attempted to make a step interpreting aging data on chronological as well as pathological scale. For this, we sampled five major tissues at regular time intervals during the entire C57BL/6J murine lifespan from a controlled in vivo aging study, measured the whole transcriptome and incorporated temporal as well as physical health aspects into the analyses. In total, we used 18 different age-related pathological parameters and transcriptomic profiles of liver, kidney, spleen, lung and brain and created a database that can now be used for a broad systems biology approach. In our study, we focused on the dynamics of biological processes during chronological aging and the comparison between chronological and pathology-related aging. PMID:24131799

  8. Aging on a different scale--chronological versus pathology-related aging.

    PubMed

    Melis, Joost P M; Jonker, Martijs J; Vijg, Jan; Hoeijmakers, Jan H J; Breit, Timo M; van Steeg, Harry

    2013-10-01

    In the next decades the elderly population will increase dramatically, demanding appropriate solutions in health care and aging research focusing on healthy aging to prevent high burdens and costs in health care. For this, research targeting tissue-specific and individual aging is paramount to make the necessary progression in aging research. In a recently published study we have attempted to make a step interpreting aging data on chronological as well as pathological scale. For this, we sampled five major tissues at regular time intervals during the entire C57BL/6J murine lifespan from a controlled in vivo aging study, measured the whole transcriptome and incorporated temporal as well as physical health aspects into the analyses. In total, we used 18 different age-related pathological parameters and transcriptomic profiles of liver, kidney, spleen, lung and brain and created a database that can now be used for a broad systems biology approach. In our study, we focused on the dynamics of biological processes during chronological aging and the comparison between chronological and pathology-related aging.

  9. A Statistical Model and Computer program for Preliminary Calculations Related to the Scaling of Sensor Arrays

    SciTech Connect

    Max Morris

    2001-04-01

    Recent advances in sensor technology and engineering have made it possible to assemble many related sensors in a common array, often of small physical size. Sensor arrays may report an entire vector of measured values in each data collection cycle, typically one value per sensor per sampling time. The larger quantities of data provided by larger arrays certainly contain more information, however in some cases experience suggests that dramatic increases in array size do not always lead to corresponding improvements in the practical value of the data. The work leading to this report was motivated by the need to develop computational planning tools to approximate the relative effectiveness of arrays of different size (or scale) in a wide variety of contexts. The basis of the work is a statistical model of a generic sensor array. It includes features representing measurement error, both common to all sensors and independent from sensor to sensor, and the stochastic relationships between the quantities to be measured by the sensors. The model can be used to assess the effectiveness of hypothetical arrays in classifying objects or events from two classes. A computer program is presented for evaluating the misclassification rates which can be expected when arrays are calibrated using a given number of training samples, or the number of training samples required to attain a given level of classification accuracy. The program is also available via email from the first author for a limited time.

  10. Scaling Relations for the Thermal Structure of Segmented Oceanic Transform Faults

    NASA Astrophysics Data System (ADS)

    Wolfson-Schwehr, M.; Boettcher, M. S.; Behn, M. D.

    2015-12-01

    Mid-ocean ridge-transform faults (RTFs) are a natural laboratory for studying strike-slip earthquake behavior due to their relatively simple geometry, well-constrained slip rates, and quasi-periodic seismic cycles. However, deficiencies in our understanding of the limited size of the largest RTF earthquakes are due, in part, to not considering the effect of short intra-transform spreading centers (ITSCs) on fault thermal structure. We use COMSOL Multiphysics to run a series of 3D finite element simulations of segmented RTFs with visco-plastic rheology. The models test a range of RTF segment lengths (L = 10-150 km), ITSC offset lengths (O = 1-30 km), and spreading rates (V = 2-14 cm/yr). The lithosphere and upper mantle are approximated as steady-state, incompressible flow. Coulomb failure incorporates brittle processes in the lithosphere, and a temperature-dependent flow law for dislocation creep of olivine activates ductile deformation in the mantle. ITSC offsets as small as 2 km affect the thermal structure underlying many segmented RTFs, reducing the area above the 600˚C isotherm, A600, and thus the size of the largest expected earthquakes, Mc. We develop a scaling relation for the critical ITSC offset length, OC, which significantly reduces the thermal affect of adjacent fault segments of length L1 and L2. OC is defined as the ITSC offset that results in an area loss ratio of R = (Aunbroken - Acombined)/Aunbroken - Adecoupled) = 63%, where Aunbroken = C600(L1+L2)1.5V-0.6 is A600 for an RTF of length L1 + L2; Adecoupled = C600(L11.5+L21.5)V-0.6 is the combined A600 of RTFs of lengths L1 and L2, respectively; and Acombined = Aunbroken exp(-O/ OC) + Adecoupled (1-exp(-O/ OC)). C600 is a constant. We use OC and kinematic fault parameters (L1, L2, O, and V) to develop a scaling relation for the approximate seismogenic area, Aseg, for each segment of a RTF system composed of two fault segments. Finally, we estimate the size of Mc on a fault segment based on Aseg. We

  11. New insights into Kilauea's volcano dynamics brought by large-scale relative relocation of microearthquakes

    USGS Publications Warehouse

    Got, J.-L.; Okubo, P.

    2003-01-01

    We investigated the microseismicity recorded in an active volcano to infer information concerning the volcano structure and long-term dynamics, by using relative relocations and focal mechanisms of microearthquakes. There were 32,000 earthquakes of the Mauna Loa and Kilauea volcanoes recorded by more than eight stations of the Hawaiian Volcano Observatory seismic network between 1988 and 1999. We studied 17,000 of these events and relocated more than 70%, with an accuracy ranging from 10 to 500 m. About 75% of these relocated events are located in the vicinity of subhorizontal decollement planes, at a depth of 8-11 km. However, the striking features revealed by these relocation results are steep southeast dipping fault planes working as reverse faults, clearly located below the decollement plane and which intersect it. If this decollement plane coincides with the pre-Mauna Loa seafloor, as hypothesized by numerous authors, such reverse faults rupture the pre-Mauna Loa oceanic crust. The weight of the volcano and pressure in the magma storage system are possible causes of these ruptures, fully compatible with the local stress tensor computed by Gillard et al. [1996]. Reverse faults are suspected of producing scarps revealed by kilometer-long horizontal slip-perpendicular lineations along the decollement surface and therefore large-scale roughness, asperities, and normal stress variations. These are capable of generating stick-slip, large-magnitude earthquakes, the spatial microseismic pattern observed in the south flank of Kilauea volcano, and Hilina-type instabilities. Rupture intersecting the decollement surface, causing its large-scale roughness, may be an important parameter controlling the growth of Hawaiian volcanoes.

  12. Relations between Arctic large-scale TEC changes and scintillations over Greenland

    NASA Astrophysics Data System (ADS)

    Durgonics, T.; Hoeg, P.; von Benzon, H. H.

    2014-12-01

    The increasing dependence on GNSS-based methods and technologies for global or regional navigation and communication has raised concerns about the impact of space weather on these systems. Temporal and spatial ionosphere variations caused by driving forces, such as changes in solar radiation, solar wind, and the Earth's magnetic field contribute to errors in satellite navigation positioning and communication systems. In this study we will focus on the impact of space weather in the Arctic region related to total electron content (TEC) and scintillation changes. Measurements from the GNSS network of stations in Greenland are analyzed and geophysical variables such as such as TEC, amplitude scintillation indices (S4), and phase scintillation indices (σϕ), are calculated together with 2D/3D electron density and scintillation maps. For the TEC we applied data from the Greenland GNET network of stations - consisting of 62 stations, while the scintillations data are based on 50 Hz sampled data from a set of sites on the west coast of Greenland (i.e., Thule, Sisimiut, and Kangerlussuaq). The GNSS-derived data is augmented by ground-based geomagnetic measurements, such as the Dst-index and magnetic H-component data obtained from the Greenland magnetic stations. Extreme ionosphere events will be presented and the underlying geophysical process will be identified and discussed. Especially results where large-scale gradients in the regional TEC are compared with the growth of scintillations. We will identify crucial elements and parameters (such as the auroral oval and the auroral electrojet), driving these changes in the Greenland TEC, S4 and σϕ distributions, in order to come up with appropriate algorithms and tools for monitoring and predicting Arctic TEC and scintillation large-scale patterns.

  13. The Relation Between Large-Scale Coronal Propagating Fronts and Type II Radio Bursts

    NASA Astrophysics Data System (ADS)

    Nitta, Nariaki V.; Liu, Wei; Gopalswamy, Nat; Yashiro, Seiji

    2014-12-01

    Large-scale, wave-like disturbances in extreme-ultraviolet (EUV) and type II radio bursts are often associated with coronal mass ejections (CMEs). Both phenomena may signify shock waves driven by CMEs. Taking EUV full-disk images at an unprecedented cadence, the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory has observed the so-called EIT waves or large-scale coronal propagating fronts (LCPFs) from their early evolution, which coincides with the period when most metric type II bursts occur. This article discusses the relation of LCPFs as captured by AIA with metric type II bursts. We show examples of type II bursts without a clear LCPF and fast LCPFs without a type II burst. Part of the disconnect between the two phenomena may be due to the difficulty in identifying them objectively. Furthermore, it is possible that the individual LCPFs and type II bursts may reflect different physical processes and external factors. In particular, the type II bursts that start at low frequencies and high altitudes tend to accompany an extended arc-shaped feature, which probably represents the 3D structure of the CME and the shock wave around it, and not just its near-surface track, which has usually been identified with EIT waves. This feature expands and propagates toward and beyond the limb. These events may be characterized by stretching of field lines in the radial direction and may be distinct from other LCPFs, which may be explained in terms of sudden lateral expansion of the coronal volume. Neither LCPFs nor type II bursts by themselves serve as necessary conditions for coronal shock waves, but these phenomena may provide useful information on the early evolution of the shock waves in 3D when both are clearly identified in eruptive events.

  14. Assessing the relative importance of surface ozone influential variables in regional-scale analysis

    NASA Astrophysics Data System (ADS)

    Lu, Wei-Zhen; Wang, Dong

    The multilayer perceptron (MLP) model is frequently used to assess the relative importance (RI) of surface ozone influential variables when they are used to investigate ozone variation mechanisms. Previous studies, however, suffer from two limitations: 1) indentifying or searching the optimal MLP topology to avoid a biased RI assessment inevitably incurs a heavy computational burden, and 2) the model is suitable only for local-scale analysis of ozone variation mechanisms. To tackle both problems, we selected three typical air-quality monitoring sites in Hong Kong as our study targets, as the ozone variations at these sites are inhomogeneously affected by regional and local factors. An MLP model trained by automatic relevance determination (referred to as MLP-ARD), a Bayesian MLP approach, was employed to assess the RI for both regional and local ozone influential variables. The results indicated the following remarks: 1) The MLP-ARD model, due to its high degree of resistance to both the over-fitting and the under-fitting problems, is exempt from identifying or searching the optimal MLP topology when used to obtain an unbiased RI assessment and thus avoid the heavy computational burden. Furthermore, the RI assessment results obtained with the MLP-ARD method are comparable to those of the best assessment method in the literature. Based on these findings, decision-makers can scientifically promulgate a site-specific air pollution control strategy site; 2) Regional-scale analysis of ozone variation is indispensable, as taking the key regional ozone influential variables into account significantly improves the prediction accuracy of the MLP-ARD model, especially on peak ozone days.

  15. Time-scaling based sliding mode control for Neuromuscular Electrical Stimulation under uncertain relative degrees.

    PubMed

    Oliveira, Tiago Roux; Costa, Luiz Rennó; Catunda, João Marcos Yamasaki; Pino, Alexandre Visintainer; Barbosa, William; Souza, Márcio Nogueira de

    2017-03-28

    This paper addresses the application of the sliding mode approach to control the arm movements by artificial recruitment of muscles using Neuromuscular Electrical Stimulation (NMES). Such a technique allows the activation of motor nerves using surface electrodes. The goal of the proposed control system is to move the upper limbs of subjects through electrical stimulation to achieve a desired elbow angular displacement. Since the human neuro-motor system has individual characteristics, being time-varying, nonlinear and subject to uncertainties, the use of advanced robust control schemes may represent a better solution than classical Proportional-Integral (PI) controllers and model-based approaches, being simpler than more sophisticated strategies using fuzzy logic or neural networks usually applied in this control problem. The objective is the introduction of a new time-scaling base sliding mode control (SMC) strategy for NMES and its experimental evaluation. The main qualitative advantages of the proposed controller via time-scaling procedure are its independence of the knowledge of the plant relative degree and the design/tuning simplicity. The developed sliding mode strategy allows for chattering alleviation due to the impact of the integrator in smoothing the control signal. In addition, no differentiator is applied to construct the sliding surface. The stability analysis of the closed-loop system is also carried out by using singular perturbation methods. Experimental results are conducted with healthy volunteers as well as stroke patients. Quantitative results show a reduction of 45% in terms of root mean square (RMS) error (from 5.9° to [Formula: see text] ) in comparison with PI control scheme, which is similar to that obtained in the literature.

  16. 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.

  17. Genome-Scale Assessment of Age-Related DNA Methylation Changes in Mouse Spermatozoa

    PubMed Central

    Kobayashi, Norio; Okae, Hiroaki; Hiura, Hitoshi; Chiba, Hatsune; Shirakata, Yoshiki; Hara, Kenshiro; Tanemura, Kentaro; Arima, Takahiro

    2016-01-01

    DNA methylation plays important roles in the production and functioning of spermatozoa. Recent studies have suggested that DNA methylation patterns in spermatozoa can change with age, but the regions susceptible to age-related methylation changes remain to be fully elucidated. In this study, we conducted genome-scale DNA methylation profiling of spermatozoa obtained from C57BL/6N mice at 8 weeks (8w), 18 weeks (18w) and 17 months of age (17m). There was no substantial difference in the global DNA methylation patterns between 18w and 17m samples except for a slight increase of methylation levels in long interspersed nuclear elements in the 17m samples. We found that maternally methylated imprinting control regions (mICRs) and spermatogenesis-related gene promoters had 5–10% higher methylation levels in 8w samples than in 18w or 17m samples. Analysis of individual sequence reads suggested that these regions were fully methylated (80–100%) in a subset of 8w spermatozoa. These regions are also known to be highly methylated in a subset of postnatal spermatogonia, which might be the source of the increased DNA methylation in 8w spermatozoa. Another possible source was contamination by somatic cells. Although we carefully purified the spermatozoa, it was difficult to completely exclude the possibility of somatic cell contamination. Further studies are needed to clarify the source of the small increase in DNA methylation in the 8w samples. Overall, our findings suggest that DNA methylation patterns in mouse spermatozoa are relatively stable throughout reproductive life. PMID:27880848

  18. A comparison of the Psychological Entitlement Scale and the Narcissistic Personality Inventory's Entitlement Scale: relations with general personality traits and personality disorders.

    PubMed

    Pryor, Lauren R; Miller, Joshua D; Gaughan, Eric T

    2008-09-01

    Given the negative consequences of psychological entitlement, it is important to have a reliable and valid measure of the construct. We used an undergraduate sample (N = 271) to examine the Entitlement subscale (ENT) of the Narcissistic Personality Inventory (Raskin & Terry, 1988) and the Psychological Entitlement Scale (PES; Campbell, Bonacci, Shelton, Exline, & Bushman, 2004) in relation to general personality traits (i.e., Revised NEO Personality Inventory; Costa & McCrae, 1992) and personality disorders (PDs; Personality Diagnostic Questionnaire-4; Hyler, 1994). We found similar personality correlates (e.g., disagreeableness; Cluster B PDs) for both measures, although ENT was comprised of greater disagreeableness and less warmth and positive affect. ENT was also more positively associated with schizoid and borderline PDs compared to the PES. Overall, these measures are closely related with regard to their relations with general and pathological personality dimensions, although the ENT scale may capture a slightly more pathological variant.

  19. City-scale analysis of water-related energy identifies more cost-effective solutions.

    PubMed

    Lam, Ka Leung; Kenway, Steven J; Lant, Paul A

    2017-02-01

    Energy and greenhouse gas management in urban water systems typically focus on optimising within the direct system boundary of water utilities that covers the centralised water supply and wastewater treatment systems, despite a greater energy influence by the water end use. This work develops a cost curve of water-related energy management options from a city perspective for a hypothetical Australian city. It is compared with that from the water utility perspective. The curves are based on 18 water-related energy management options that have been implemented or evaluated in Australia. In the studied scenario, the cost-effective energy saving potential from a city perspective (292 GWh/year) is far more significant than that from a utility perspective (65 GWh/year). In some cases, for similar capital cost, if regional water planners invested in end use options instead of utility options, a greater energy saving potential at a greater cost-effectiveness could be achieved in urban water systems. For example, upgrading a wastewater treatment plant for biogas recovery at a capital cost of $27.2 million would save 31 GWh/year with a marginal cost saving of $63/MWh, while solar hot water system rebates at a cost of $28.6 million would save 67 GWh/year with a marginal cost saving of $111/MWh. Options related to hot water use such as water-efficient shower heads, water-efficient clothes washers and solar hot water system rebates are among the most cost-effective city-scale opportunities. This study demonstrates the use of cost curves to compare both utility and end use options in a consistent framework. It also illustrates that focusing solely on managing the energy use within the utility would miss substantial non-utility water-related energy saving opportunities. There is a need to broaden the conventional scope of cost curve analysis to include water-related energy and greenhouse gas at the water end use, and to value their management from a city perspective. This

  20. Size and scaling in the mandible of living and extinct apes.

    PubMed

    Ravosa, M J

    2000-01-01

    The purpose of this study is to fill a gap in our knowledge of dietary and allometric determinants of masticatory function and mandibular morphology in major catarrhine clades. To extend the implications of previous work on variation in mandibular form and function in other primates, a scaling analysis was performed on 20 extinct and 7 living non-cercopithecoid catarrhines or 'dental apes'. Results of allometric comparisons indicate that for a given jaw length, larger apes exhibit significantly more robust corpora and symphyses than smaller forms. This appears linked to size-related increases in dietary toughness and/or hardness, which in turn causes elevated mandibular loads and/or greater repetitive loading during unilateral mastication. Larger-bodied dental apes also display more curved symphyses, which also explains the positive allometry of symphysis width and height. In apes, proconsulids often evince more robust jaws while all hylobatids, Pan and Dryopithecus laietanus possess more gracile cross sections. In propliopithecids, Aegyptopithecus is always more robust than Propliopithecus. In proconsulids, Rangwapithecus and Micropithecus commonly exhibit more robust jaws whereas Dendropithecus and especially Simiolus are more gracile. Most of the larger taxa are folivorous and/or hard-object frugivorous pongids with relatively larger dentaries. Though apes have relatively wider corpora than cercopithecines due to greater axial twisting of the corpora during chewing, they are otherwise alike in robusticity levels. Smaller apes are similar to cercopithecines in evincing a relatively high degree of symphyseal curvature, while larger taxa are like colobines in having less curvature. Larger pongids resemble or even exceed colobine jaw proportions and thus appear to converge on colobines in terms of the mechanical properties of their diets.

  1. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone.

    PubMed

    Osland, Michael J; Day, Richard H; Larriviere, Jack C; From, Andrew S

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  2. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone

    USGS Publications Warehouse

    Osland, Michael J.; Day, Richard H.; Larriviere, Jack C.; From, Andrew S.

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  3. Relation between Transport Properties and Heterogeneities from Grain and Sample Scale in Fontainebleau Sandstone

    NASA Astrophysics Data System (ADS)

    Song, I.; Graphchikov, A.; Renner, J.

    2004-12-01

    We carried out an experimental study of Fontainebleau sandstone for correlation between pore structure and transport properties. Eight blocks of the sandstone were available from different locations. Several cored samples, 30 mm in diameter and 60 mm in length, were prepared from each block. The available blocks yield a range in porosity from about 3 to 11% with no difference between connected and total porosity. Scanning Electronic Microscope analysis revealed a clayless-pure (>99% quartz), well sorted sandstone with different porosity and pore geometry for different blocks. The pore texture varies from ¡risolated pores¡_ to ¡risolated grains¡_ in two-dimensional images. To further constrain the effect of heterogeneities in sample scale on bulk fluid transport properties we tested samples with up to six sawcuts parallel or perpendicular to the flow direction. The planar faces of the saw cuts were machined to a smooth finish. We also stacked pieces alternating between two sandstone varieties of 6 and 9% porosity to model inhomogeneity for one-dimensional fluid transport varying in scale. On intact sample, we measured ultrasonic velocity, electrical conductivity, hydraulic permeability and specific storage. Ultrasonic velocity and electrical conductivity were measured on as-is, oven-dry, and water-saturated samples at room temperature and atmospheric pressure. Permeability and specific storage were determined from steady state, linear injection and oscillatory tests at different effective pressures ranging up to 200 MPa at room temperature. The variation of the ultrasonic velocity covers the full range between the lower and the upper Hashin-Shtrickman bound. The velocity ranges relate to the pore geometry rather than porosity; e.g. high velocity in samples with ¡risolated pores¡_ and low velocity in samples with ¡risolated grains¡_. The electric impedance and hydraulic permeability of the sandstone correlates strongly with the connected porosity. The

  4. The Richter Scale of Reduction: decoupling management and climatic related drivers of water conservation behavior

    NASA Astrophysics Data System (ADS)

    Rippy, Megan; Hemati, Azadeh; Grant, Stanley

    2016-04-01

    As global populations grow, cities in drought prone regions of the world such as South East Australia are faced with escalating water scarcity and water security challenges. The management approaches geared towards addressing these challenges are diverse, and background climatic variability further complicates the story. Here we use Melbourne, a city of 4.3 million people in South East Australia that recently faced and overcame a > 10 year "Millennium" drought, as a test case for evaluating the relative importance of various management-related and climatic factors in driving reductions in municipal water consumption (>50% in 12 years). Our analysis suggests that Melbourne's declining municipal consumption cannot be explained by potable substitution alone, as reductions in municipal consumption were not matched by increased use of alternative sources (e.g., urban rain or recycled water). Savings from non revenue water (NRW) reduction (through leak reduction and improved metering) also fell short of the total savings achieved during the drought. In the final analysis, conservation behavior emerged as the dominant driver of municipal water savings, forming a so-called "Richter Scale of Reduction" with conservation saving ~10 fold more water than NRW reduction, which in turn saved ~10 fold more water than alternative water sources. We also used wavelet analysis to illustrate that conservation behavior responds to climate variability at a variety of frequencies (annual-decadal and longer) which correspond to perturbations that impact water system vulnerability and sustainability. Interestingly the shared power of climatic and conservation responses declined as the drought progressed, perhaps reflecting the adoption of more consistent conservation behavior as the drought became increasingly severe.

  5. The 1868 Hayward fault, California, earthquake: Implications for earthquake scaling relations on partially creeping faults

    USGS Publications Warehouse

    Hough, Susan E.; Martin, Stacey

    2015-01-01

    The 21 October 1868 Hayward, California, earthquake is among the best-characterized historical earthquakes in California. In contrast to many other moderate-to-large historical events, the causative fault is clearly established. Published magnitude estimates have been fairly consistent, ranging from 6.8 to 7.2, with 95% confidence limits including values as low as 6.5. The magnitude is of particular importance for assessment of seismic hazard associated with the Hayward fault and, more generally, to develop appropriate magnitude–rupture length scaling relations for partially creeping faults. The recent reevaluation of archival accounts by Boatwright and Bundock (2008), together with the growing volume of well-calibrated intensity data from the U.S. Geological Survey “Did You Feel It?” (DYFI) system, provide an opportunity to revisit and refine the magnitude estimate. In this study, we estimate the magnitude using two different methods that use DYFI data as calibration. Both approaches yield preferred magnitude estimates of 6.3–6.6, assuming an average stress drop. A consideration of data limitations associated with settlement patterns increases the range to 6.3–6.7, with a preferred estimate of 6.5. Although magnitude estimates for historical earthquakes are inevitably uncertain, we conclude that, at a minimum, a lower-magnitude estimate represents a credible alternative interpretation of available data. We further discuss implications of our results for probabilistic seismic-hazard assessment from partially creeping faults.

  6. Relative influence upon microwave emissivity of fine-scale stratigraphy, internal scattering, and dielectric properties

    USGS Publications Warehouse

    England, A.W.

    1976-01-01

    The microwave emissivity of relatively low-loss media such as snow, ice, frozen ground, and lunar soil is strongly influenced by fine-scale layering and by internal scattering. Radiometric data, however, are commonly interpreted using a model of emission from a homogeneous, dielectric halfspace whose emissivity derives exclusively from dielectric properties. Conclusions based upon these simple interpretations can be erroneous. Examples are presented showing that the emission from fresh or hardpacked snow over either frozen or moist soil is governed dominantly by the size distribution of ice grains in the snowpack. Similarly, the thickness of seasonally frozen soil and the concentration of rock clasts in lunar soil noticeably affect, respectively, the emissivities of northern latitude soils in winter and of the lunar regolith. Petrophysical data accumulated in support of the geophysical interpretation of microwave data must include measurements of not only dielectric properties, but also of geometric factors such as finescale layering and size distributions of grains, inclusions, and voids. ?? 1976 Birkha??user Verlag.

  7. Visualization of large scale geologically related data in virtual 3D scenes with OpenGL

    NASA Astrophysics Data System (ADS)

    Seng, Dewen; Liang, Xi; Wang, Hongxia; Yue, Guoying

    2007-11-01

    This paper demonstrates a method for three-dimensional (3D) reconstruction and visualization of large scale multidimensional surficial, geological and mine planning data with the programmable visualization environment OpenGL. A simulation system developed by the authors is presented for importing, filtering and visualizing of multidimensional geologically related data. The approach for the visual simulation of complicated mining engineering environment implemented in the system is described in detail. Aspects like presentations of multidimensional data with spatial dependence, navigation in the surficial and geological frame of reference and in time, interaction techniques are presented. The system supports real 3D landscape representations. Furthermore, the system provides many visualization methods for rendering multidimensional data within virtual 3D scenes and combines them with several navigation techniques. Real data derived from an iron mine in Wuhan City of China demonstrates the effectiveness and efficiency of the system. A case study with the results and benefits achieved by using real 3D representations and navigations of the system is given.

  8. German National Proficiency Scales in Biology: Internal Structure, Relations to General Cognitive Abilities and Verbal Skills

    PubMed Central

    KÖLLER, OLAF

    2016-01-01

    ABSTRACT National and international large‐scale assessments (LSA) have a major impact on educational systems, which raises fundamental questions about the validity of the measures regarding their internal structure and their relations to relevant covariates. Given its importance, research on the validity of instruments specifically developed for LSA is still sparse, especially in science and its subdomains biology, chemistry, and physics. However, policy decisions for the improvement of educational quality based on LSA can only be helpful if valid information on students’ achievement levels is provided. In the present study, the nature of the measurement instruments based on the German Educational Standards in Biology is examined. On the basis of data from 3,165 students in Grade 10, we present dimensional analyses and report the relationship between different subdimensions of biology literacy and cognitive covariates such as general cognitive abilities and verbal skills. A theory‐driven two‐dimensional model fitted the data best. Content knowledge and scientific inquiry, two subdimensions of biology literacy, are highly correlated and show differential correlational patterns to the covariates. We argue that the underlying structure of biology should be incorporated into curricula, teacher training and future assessments. PMID:27818532

  9. Consistent rationalization of type-2 topoisomerases' unknotting, decatenating, supercoil-relaxing actions and their scaling relation

    NASA Astrophysics Data System (ADS)

    Liu, Zhirong; Chan, Hue Sun

    2015-09-01

    How type-2 topoisomerases discern global topology from local properties of DNA is not known precisely but the hypothesis that the enzymes selectively pass double-helix strands at hook-like juxtapositions is promising. Building upon an investigation of unknotting and decatenating using an improved wormlike DNA model, here we focus primarily on the enzymes' action in narrowing the distribution of linking number (Lk) in supercoiled DNA. Consistent with experiments, with selective passage at a hooked juxtaposition, the simulated narrowing factor RLk diminishes with decreasing DNA circle size but approaches an asymptotic RLk ≈ 1.7-1.8 for circle size ≳3.5 kb. For the larger DNA circles, we found that (RLk - 1) ≈ 0.42log10RK ≈ 0.68log10RL and thus RK ≈ (RL)1.6 holds for the computed RLk and knot and catenane reduction factors RK and RL attained by selective passage at different juxtaposition geometries. Remarkably, this general scaling relation is essentially identical to that observed experimentally for several type-2 topoisomerases from a variety of organisms, indicating that the different disentangling powers of the topoisomerases likely arise from variations in the hooked geometries they select. Taken together, our results suggest strongly that type-2 topoisomerases recognize not only the curvature of the G-segment but also that of the T-segment.

  10. Determining stellar parameters of asteroseismic targets: going beyond the use of scaling relations

    NASA Astrophysics Data System (ADS)

    Rodrigues, Thaíse S.; Bossini, Diego; Miglio, Andrea; Girardi, Léo; Montalbán, Josefina; Noels, Arlette; Trabucchi, Michele; Coelho, Hugo Rodrigues; Marigo, Paola

    2017-01-01

    Asteroseismic parameters allow us to measure the basic stellar properties of field giants observed far across the Galaxy. Most of such determinations are, up to now, based on simple scaling relations involving the large frequency separation, Δν, and the frequency of maximum power, νmax. In this work, we implement Δν and the period spacing, ΔP, computed along detailed grids of stellar evolutionary tracks, into stellar isochrones and hence in a Bayesian method of parameter estimation. Tests with synthetic data reveal that masses and ages can be determined with typical precision of 5 and 19 per cent, respectively, provided precise seismic parameters are available. Adding independent information on the stellar luminosity, these values can decrease down to 3 and 10 per cent respectively. The application of these methods to NGC 6819 giants produces a mean age in agreement with those derived from isochrone fitting, and no evidence of systematic differences between RGB and RC stars. The age dispersion of NGC 6819 stars, however, is larger than expected, with at least part of the spread ascribable to stars that underwent mass-transfer events.

  11. Strong anisotropy in two-dimensional surfaces with generic scale invariance: Gaussian and related models.

    PubMed

    Vivo, Edoardo; Nicoli, Matteo; Cuerno, Rodolfo

    2012-11-01

    Among systems that display generic scale invariance, those whose asymptotic properties are anisotropic in space (strong anisotropy, SA) have received relatively less attention, especially in the context of kinetic roughening for two-dimensional surfaces. This is in contrast with their experimental ubiquity, e.g., in the context of thin-film production by diverse techniques. Based on exact results for integrable (linear) cases, here we formulate a SA ansatz that, albeit equivalent to existing ones borrowed from equilibrium critical phenomena, is more naturally adapted to the type of observables that are measured in experiments on the dynamics of thin films, such as one- and two-dimensional height structure factors. We test our ansatz on a paradigmatic nonlinear stochastic equation displaying strong anisotropy like the Hwa-Kardar equation [Phys. Rev. Lett. 62, 1813 (1989)], which was initially proposed to describe the interface dynamics of running sand piles. A very important role to elucidate its SA properties is played by an accurate (Gaussian) approximation through a nonlocal linear equation that shares the same asymptotic properties.

  12. Worldwide F(ST) estimates relative to five continental-scale populations.

    PubMed

    Steele, Christopher D; Court, Denise Syndercombe; Balding, David J

    2014-11-01

    We estimate the population genetics parameter FST (also referred to as the fixation index) from short tandem repeat (STR) allele frequencies, comparing many worldwide human subpopulations at approximately the national level with continental-scale populations. FST is commonly used to measure population differentiation, and is important in forensic DNA analysis to account for remote shared ancestry between a suspect and an alternative source of the DNA. We estimate FST comparing subpopulations with a hypothetical ancestral population, which is the approach most widely used in population genetics, and also compare a subpopulation with a sampled reference population, which is more appropriate for forensic applications. Both estimation methods are likelihood-based, in which FST is related to the variance of the multinomial-Dirichlet distribution for allele counts. Overall, we find low FST values, with posterior 97.5 percentiles < 3% when comparing a subpopulation with the most appropriate population, and even for inter-population comparisons we find FST < 5%. These are much smaller than single nucleotide polymorphism-based inter-continental FST estimates, and are also about half the magnitude of STR-based estimates from population genetics surveys that focus on distinct ethnic groups rather than a general population. Our findings support the use of FST up to 3% in forensic calculations, which corresponds to some current practice.

  13. German National Proficiency Scales in Biology: Internal Structure, Relations to General Cognitive Abilities and Verbal Skills.

    PubMed

    Kampa, Nele; Köller, Olaf

    2016-09-01

    National and international large-scale assessments (LSA) have a major impact on educational systems, which raises fundamental questions about the validity of the measures regarding their internal structure and their relations to relevant covariates. Given its importance, research on the validity of instruments specifically developed for LSA is still sparse, especially in science and its subdomains biology, chemistry, and physics. However, policy decisions for the improvement of educational quality based on LSA can only be helpful if valid information on students' achievement levels is provided. In the present study, the nature of the measurement instruments based on the German Educational Standards in Biology is examined. On the basis of data from 3,165 students in Grade 10, we present dimensional analyses and report the relationship between different subdimensions of biology literacy and cognitive covariates such as general cognitive abilities and verbal skills. A theory-driven two-dimensional model fitted the data best. Content knowledge and scientific inquiry, two subdimensions of biology literacy, are highly correlated and show differential correlational patterns to the covariates. We argue that the underlying structure of biology should be incorporated into curricula, teacher training and future assessments.

  14. Analysis of earthquake body wave spectra for potency and magnitude values: implications for magnitude scaling relations

    NASA Astrophysics Data System (ADS)

    Ross, Zachary E.; Ben-Zion, Yehuda; White, Malcolm C.; Vernon, Frank L.

    2016-11-01

    We develop a simple methodology for reliable automated estimation of the low-frequency asymptote in seismic body wave spectra of small to moderate local earthquakes. The procedure corrects individual P- and S-wave spectra for propagation and site effects and estimates the seismic potency from a stacked spectrum. The method is applied to >11 000 earthquakes with local magnitudes 0 < ML < 4 that occurred in the Southern California plate-boundary region around the San Jacinto fault zone during 2013. Moment magnitude Mw values, derived from the spectra and the scaling relation of Hanks & Kanamori, follow a Gutenberg-Richter distribution with a larger b-value (1.22) from that associated with the ML values (0.93) for the same earthquakes. The completeness magnitude for the Mw values is 1.6 while for ML it is 1.0. The quantity (Mw - ML) linearly increases in the analysed magnitude range as ML decreases. An average earthquake with ML = 0 in the study area has an Mw of about 0.9. The developed methodology and results have important implications for earthquake source studies and statistical seismology.

  15. Photosynthesis and stomatal conductance related to reflectance on the canopy scale

    SciTech Connect

    Verma, S.B.; Kim, J. ); Sellers, P.J.; Hall, F.G.; Goetz, S.J. ); Walthall, C.L. )

    1993-04-01

    Field measurements of carbon dioxide and water vapor fluxes were analyzed in conjunction with reflectances obtained from a helicopter-mounted Modular Multiband Radiometer (MMR) at a grassland study site during the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE). These measurements are representative of the canopy scale and were made over a range of meteorological and soil moisture conditions during different stages in the annual life cycle of the prairie vegetation, and thus provide a good basis for investigating hypotheses/relationships potentially useful in remote sensing applications. The authors tested the hypothesis (Sellers, 1987) that the simple ratio vegetation index (SR) should be near-linearly related to the derivatives of the unstressed canopy stomatal conductance (g[sub c]*) and the unstressed canopy photosynthesis (P[sub c]*) with respect to photosynthetically active radiation (PAR). Even though there is some scatter in the data, the results seem to support this hypothesis. Further investigation, however, is needed before such relationships can be employed in satellite remote sensing applications.

  16. Implementing a Resource-Based Relative Value Scale Fee Schedule for Physician Services

    PubMed Central

    Wynn, Barbara O.; Liu, Hangsheng; Mulcahy, Andrew W.; Okeke, Edward N.; Iyer, Neema; Painter, Lawrence S.

    2014-01-01

    Abstract A RAND study used 2011 medical data to examine the impact of implementing a resource-based relative value scale to pay for physician services under the California workers' compensation system. Current allowances under the Official Medical Fee Schedule are approximately 116 percent of Medicare-allowed amounts and, by law, will transition to 120 percent of Medicare over four years. Using Medicare policies to establish the fee-schedule amounts, aggregate allowances are estimated to decrease for four types of service by the end of the transition in 2017: anesthesia (−16.5 percent), surgery (−19.9 percent), radiology (−16.5 percent), and pathology (−29.0 percent). Aggregate allowances for evaluation and management visits are estimated to increase by 39.5 percent. Allowances for services classified as “medicine” in the Current Procedural Terminology codebook will increase by 17.3 percent. In the aggregate, across all services, allowances are projected to increase 11.9 percent. Because most specialties furnish different types of services, the impacts by specialty are generally less than the impacts by type of service. PMID:28083336

  17. Ecotoxicity and environmental safety related to nano-scale zerovalent iron remediation applications.

    PubMed

    Semerád, Jaroslav; Cajthaml, Tomáš

    2016-12-01

    This mini-review summarizes the current information that has been published on the various effects of nano-scale zerovalent iron (nZVI) on microbial biota, with an emphasis on reports that highlight the positive aspects of its application or its stimulatory effects on microbiota. By nature, nZVI is a highly reactive substance; thus, the possibility of nZVI being toxic is commonly suspected. Accordingly, the cytotoxicity of nZVI and the toxicity of nZVI-related products have been detected by laboratory tests and documented in the literature. However, there are numerous other published studies on its useful nature, which are usually skipped in reviews that deal only with the phenomenon of toxicity. Therefore, the objective of this article is to review both recent publications reporting the toxic effects of nZVI on microbiota and studies documenting the positive effects of nZVI on various environmental remediation processes. Although cytotoxicity is an issue of general importance and relevance, nZVI can reduce the overall toxicity of a contaminated site, which ultimately results in the creation of better living conditions for the autochthonous microflora. Moreover, nZVI changes the properties of the site in a manner such that it can also be used as a tool in a tailor-made approach to support a specific microbial community for the decontamination of a particular polluted site.

  18. Family attitude scale: measurement of criticism in the relatives of patients with schizophrenia in Japan.

    PubMed

    Fujita, Hirokazu; Shimodera, Shinji; Izumoto, Yuji; Tanaka, Shuichi; Kii, Masaru; Mino, Yoshio; Inoue, Shimpei

    2002-07-31

    Expressed emotion (EE) is traditionally measured with the Camberwell Family Interview (CFI), but the CFI requires considerable time for both execution and evaluation. As an alternative, we investigated the validity of the Family Attitude Scale (FAS), a questionnaire developed for the measurement of EE. The CFI, the FAS, the General Health Questionnaire (GHQ), and the Five-Minute Speech Sample (FMSS) were administered in 57 members of the families of 41 patients with acute episodes of schizophrenia. The relative sensitivity and specificity of EE assessment with the FAS compared with the criticism component of the CFI were 100% and 88.5%, respectively. EE assessment based on criticism as assessed with the FMSS compared with the CFI had a sensitivity of 40.0% and a specificity of 90.4%. The GHQ score tended to be higher in the high-scoring FAS group than in the low-scoring FAS group. The FAS showed excellent validity for the measurement of critical aspects of family attitudes, and the FAS score reflected the state of psychological health of the families.

  19. Ontology-based annotations and semantic relations in large-scale (epi)genomics data.

    PubMed

    Galeota, Eugenia; Pelizzola, Mattia

    2016-05-03

    Public repositories of large-scale biological data currently contain hundreds of thousands of experiments, including high-throughput sequencing and microarray data. The potential of using these resources to assemble data sets combining samples previously not associated is vastly unexplored. This requires the ability to associate samples with clear annotations and to relate experiments matched with different annotation terms. In this study, we illustrate the semantic annotation of Gene Expression Omnibus samples metadata using concepts from biomedical ontologies, focusing on the association of thousands of chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) samples with a given target, tissue and disease state. Next, we demonstrate the feasibility of quantitatively measuring the semantic similarity between different samples, with the aim of combining experiments associated with the same or similar semantic annotations, thus allowing the generation of large data sets without the need of additional experiments. We compared tools based on Unified Medical Language System with tools that use topic-specific ontologies, showing that the second approach outperforms the first both in the annotation process and in the computation of semantic similarity measures. Finally, we demonstrated the potential of this approach by identifying semantically homogeneous groups of ChIP-seq samples targeting the Myc transcription factor, and expanding this data set with semantically coherent epigenetic samples. The semantic information of these data sets proved to be coherent with the ChIP-seq signal and with the current knowledge about this transcription factor.

  20. Allometric and Non-Allometric Patterns in Sexual Dimorphism Discrimination of Wing Shape in Ophion intricatus: Might Two Male Morphotypes Coexist?

    PubMed Central

    Benítez, Hugo A.; Bravi, Raffaella; Parra, Luis E.; Sanzana, Maria-Jose; Sepúlveda-Zúñiga, Einer

    2013-01-01

    Bees and wasps could exhibit shape and size sexual dimorphism, and most of their morphological variation could depend on phenotypic responses due to environmental pressure during ontogenetic development. More complex measurement techniques related to size and shape rather than simply to mass and length should be required to analyze such a complex sexual dimorphism. In this study, differences related to wing shape and size of males and females of Ophion intricatus Brullé (Hymenoptera: Ichneumonidae) were evaluated using geometric morphometrics. Right and left wings of specimens were used, and a photographic matrix was constructed in which 18 morphological landmarks based on shape and vein patterns of the wings were digitalized. A multivariate analysis of wing shape showed significant differences between sexes and sites. The geometric variation demonstrated that the points at the intersection of radial and cubital-anal veins might be key characters to differentiate between sexes. This study also showed the presence of two clearly different male morphotypes coexisting in the same study site. However, it should be noted that the results of this study showed that the variation in wing shape is an analytical character in the determination of sexual differences in the family Ichneumonidae. These differences raise the question of whether sexual dimorphism of wing shape may be modulated by natural selection. PMID:24766555

  1. Probing cosmology and galaxy cluster structure with the Sunyaev-Zel'dovich decrement versus X-ray temperature scaling relation

    NASA Astrophysics Data System (ADS)

    Shang, Cien; Haiman, Zoltán; Verde, Licia

    2009-12-01

    Scaling relations among galaxy cluster observables, which will become available in large future samples of galaxy clusters, could be used to constrain not only cluster structure, but also cosmology. We study the utility of this approach, employing a physically motivated parametric model to describe cluster structure and applying it to the expected relation between the Sunyaev-Zel'dovich decrement (Sν) and the emission-weighted X-ray temperature (Tew). The slope and normalization of the entropy profile, the concentration of the dark matter potential, the pressure at the virial radius and the level of non-thermal pressure support as well as the mass and redshift dependence of these quantities are described by free parameters. With a suitable choice of fiducial parameter values, the cluster model satisfies several existing observational constraints. We employ a Fisher matrix approach to estimate the joint errors on cosmological and cluster structure parameters from a measurement of Sν versus Tew in a future survey. We find that different cosmological parameters affect the scaling relation differently: predominantly through the baryon fraction (Ωm and Ωb), the virial overdensity (w0 and wa for low-z clusters) and the angular diameter distance (w0 and wa for high-z clusters; ΩDE and h). We find that the cosmology constraints from the scaling relation are comparable to those expected from the number counts (dN/dz) of the same clusters. The scaling-relation approach is relatively insensitive to selection effects and it offers a valuable consistency check; combining the information from the scaling relation and dN/dz is also useful to break parameter degeneracies and help disentangle cluster physics from cosmology. Our work suggests that scaling relations should be a useful component in extracting cosmological information from large future cluster surveys.

  2. Testing SMBH scaling relations using cosmological simulations and optical/near-IR imaging data

    NASA Astrophysics Data System (ADS)

    Mutlu Pakdil, Burcin; Seigar, Marc S.; Davis, Benjamin L.; Treuthardt, Patrick M.; Berrier, Joel

    2017-01-01

    The strong correlation between supermassive black hole (SMBH) mass and a number of measurable features of the host galaxies has generated great interest in the notion that galaxy formation and SMBH growth are closely linked. My dissertation has focused primarily on the SMBH-host galaxy scaling relations and their implications for galaxy evolution. First, we use the statistically tightest correlations with SMBH mass, which are the Sersic index for early-type galaxies and pitch angle for spiral galaxies, to predict the SMBH masses in our volume-limited sample, and derive the SMBH mass function (BHMF), and quantify the SMBH space density in our local universe. I will present the observational simplicity of our approach to estimate the local BHMF through imaging data only as well as our BHMF estimate and its implications. Our result is as of a particular interest because it is derived from a nearly complete sample within set limits and provides reliable data, especially for the low-mass end of the local BHMF.Next, we study the data from Illustris simulation project, which is a large cosmological simulation of galaxy formation. This simulation provides a statistically large and representative sample of objects, and makes it possible to disentangle the physical link between black holes and their host galaxies. We derive the spiral arm morphology in the multi-wavelength, and test the theories of spiral structure in the simulated disk galaxies. We further study the Illustris prediction for the SMBH mass-spiral arm pitch angle relation and check if the result produces the slope and normalization of the observed SMBH mass-spiral arm pitch angle relation. A careful assessment of the agreement/disagreement with observations is the primary test of the physics implemented in the simulation. I will present our results from the Illustris spiral galaxies, and discuss the implications on which galaxy types are strongly physically linked with their central SMBHs and which are much

  3. 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

    Microwave remote sensing is capable of developing soil moisture maps through satellite data. The resulting maps are useful indicators of hydrologic conditions. Water concentrations are deterministic of flooding events and potential agricultural resources. The emitted microwave radiation of soil is influenced by its moisture content. Models have been developed to incorporate parameters besides soil moisture that affect the emitted microwave radiation. We are interested in one of these parameters known as the optical depth. Optical depth is the effect of the canopy on the observed emission of microwaves. The vegetation directly competes with soil moisture as a contributor to the emitted microwave radiation and the optical depth appears within every term in the present satellite retrieval algorithm. Optical depth has been shown to be directly proportional to the amount of water contained within vegetation tissue. Allometry is a way to effectively and efficiently measure vegetation water content through the way the parts of the organism change in proportion to each other in response to growth. Vegetation water content is difficult to measure without taking destructive measurements, in addition to involving too much time and manual labor. Therefore, another component of vegetation can be measured in relation to vegetation water content which can then be related to optical depth. In our study we worked in soybean, a major crop in many areas of the world. We compared soybean vegetation water content to an estimate of the volume of an individual plant expressed as the product of canopy height and stem diameter squared (Zc*Sd2), both of which can be measured easily and nondestructively. We also wished to determine whether vegetation water content remained constant as a percentage to total biomass over the length of the growing season. Agricultural yield is most likely a function of the total dry mass of vegetation. Establishing the relationship between vegetation water

  4. Testing Scaling Relations for Solar-like Oscillations from the Main Sequence to Red Giants Using Kepler Data

    NASA Astrophysics Data System (ADS)

    Huber, D.; Bedding, T. R.; Stello, D.; Hekker, S.; Mathur, S.; Mosser, B.; Verner, G. A.; Bonanno, A.; Buzasi, D. L.; Campante, T. L.; Elsworth, Y. P.; Hale, S. J.; Kallinger, T.; Silva Aguirre, V.; Chaplin, W. J.; De Ridder, J.; García, R. A.; Appourchaux, T.; Frandsen, S.; Houdek, G.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Broomhall, A. M.; Corsaro, E.; Salabert, D.; Sanderfer, D. T.; Seader, S. E.; Smith, J. C.

    2011-12-01

    We have analyzed solar-like oscillations in ~1700 stars observed by the Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling relations for the frequency of maximum power (νmax), the large frequency separation (Δν), and oscillation amplitudes. We show that the difference of the Δν-νmax relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M) s scaling nor the revised scaling relation by Kjeldsen & Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of ~25%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation.

  5. [Organizational well-being and work-related stress in health care organizations: validation of the Work-related Stress Assessment Scale].

    PubMed

    Coluccia, Anna; Lorini, Francesca; Ferretti, Fabio; Pozza, Andrea; Gaetani, Marco

    2015-01-01

    The issue of the assessment of work-related stress has stimulated in recent years, the production of several theoretical paradigms and assessment tools. In this paper we present a new scale for the assessment of organizational well-being and work-related stress specific for healthcare organizations (Work-related Stress Assessment Scale - WSAS). The goal of the authors is to examine the psychometric properties of the scale, so that it can be used in the healthcare setting as a work-related stress assessment tool. The answers of 230 healthcare professionals belonging to different roles have been analyzed. The study was realized in 16 Units of the University Hospital "S. Maria alle Scotte "of Siena. The exploratory factor analysis (EFA) revealed the presence of five factors with good internal consistency and reliability, "relationship to the structure of proximity" (α = 0.93) "change" (α = 0.92), "organization of work "(α = 0.81)," relationship with the company / Governance "(α = 0.87)" working environment "(α = 0.83). The analysis of SEM (Structural Equation Models) has confirmed the goodness of the factor solution (NNFI = 0.835, CFI = 0.921, RMSEA = 0.060). The good psychometric qualities, the shortness and simplicity of the scale WSAS makes it a useful aid in the assessment of work-related stress in health care organizations.

  6. The Post-Deployment Reintegration Scale: Associations with Organizational Commitment, Job-Related Affect, and Career Intentions

    DTIC Science & Technology

    2006-11-01

    The post-deployment reintegration scale: Associations with organizational commitment, job-related affect, and career intentions Ann-Renée Blais...Recherche et développement pour la défense Canada DEFENCE DÉFENSE & The post-deployment reintegration scale: Associations with organizational... reintegration can lead to intra- and/or inter-personal changes that may influence the quality of their relationships with family, friends, and

  7. Using Relational Reasoning to Learn about Scientific Phenomena at Unfamiliar Scales

    ERIC Educational Resources Information Center

    Resnick, Ilyse; Davatzes, Alexandra; Newcombe, Nora S.; Shipley, Thomas F.

    2017-01-01

    Many scientific theories and discoveries involve reasoning about extreme scales, removed from human experience, such as time in geology and size in nanoscience. Thus, understanding scale is central to science, technology, engineering, and mathematics. Unfortunately, novices have trouble understanding and comparing sizes of unfamiliar large and…

  8. Scale issues in soil hydrology related to measurement and simulation: A case study in Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    State variables, such as soil water content (SWC), are typically measured or inferred at very small scales while being simulated at larger scales relevant to spatial management or hillslope areas. Thus there is an implicit spatial disparity that is often ignored. Surface runoff, on the other hand, ...

  9. Using Relational Reasoning to Learn about Scientific Phenomena at Unfamiliar Scales

    ERIC Educational Resources Information Center

    Resnick, Ilyse; Davatzes, Alexandra; Newcombe, Nora S.; Shipley, Thomas F.

    2016-01-01

    Many scientific theories and discoveries involve reasoning about extreme scales, removed from human experience, such as time in geology, size in nanoscience. Thus, understanding scale is central to science, technology, engineering, and mathematics. Unfortunately, novices have trouble understanding and comparing sizes of unfamiliar large and small…

  10. Career Adapt-Abilities Scale-USA Form: Psychometric Properties and Relation to Vocational Identity

    ERIC Educational Resources Information Center

    Porfeli, Erik J.; Savickas, Mark L.

    2012-01-01

    This article reports construction and initial validation of the United States form of the Career Adapt-Abilities Scale (CAAS). The CAAS 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.…

  11. Laboratory experiments for defining scaling relations between rock material properties and rock resistance to erosion

    NASA Astrophysics Data System (ADS)

    Sklar, L. S.; Beyeler, J. D.; Collins, G. C.; Farrow, J. W.; Hsu, L.; Litwin, K. L.; Polito, P. J.

    2012-12-01

    that relative erodibility (for fixed erosive forcing and variable rock type) is well-predicted by power functions of tensile strength and grain size for each of the erosional processes studied. This result is consistent with fracture mechanics theory applied to brittle materials subjected to low (sub-ballistic) velocity impacts or collisions. Theory suggests that absolute erodiblity can be quantified as the impact kinetic energy required to detach a unit volume of material, which can be parameterized as a power function of tensile strength, elastic modulus and grain size. Theory also helps explain the high degree of correlation among many of the rock material properties we measured, an attribute of the data set that can be used to develop other predictive relations using more-easily measured rock attributes such as dry bulk density or Schmidt hammer rebound number. These relationships can be used for temporal scaling where weak materials are used in the laboratory to accelerate erosion processes that are much slower in strong rocks in the field, and for collapsing field and lab erosion rate measurements collected across multiple rock types. The community would benefit from a shared database of linked measurements of rock material properties, erosion rates, and details of erosion dynamics for a variety of rock detachment mechanisms.

  12. Developing a scale to measure family dynamics related to long-term care, and testing that scale in a multicenter cross-sectional study

    PubMed Central

    2014-01-01

    Background As Japan’s population ages, more frail elderly people are cared for by members of their family. The dynamics within such families are difficult to study, in part because they are difficult to quantify. We developed a scale for assessing family dynamics related to long-term care. Here we report on the development of that scale, and we present the results of reliability testing and validation testing. Methods Two primary-care specialists drafted questions about family dynamics, and discussed them with other primary-care physicians and clinical researchers. The final questionnaire asked about four problems or undesirable situations: disengagement (emotional distance), scapegoating (inappropriate blame), transfer of problems across generations (transfer of unnecessary burden from older to younger generations, trans-generationally displaced revenge), and undesirable behavior (co-dependence). Next, at six general-medicine clinics, doctors evaluated families that had a caregiver and a patient requiring long-term care. The results were analyzed by factor analysis. Cronbach’s α was computed, and criterion-related validation tests were done with three types of criteria: relationship before caregiving, ability to do activities of daily living (ADL), and the duration of care. Results Results were obtained from 199 families. Among the caregivers, 79% were women and their mean age was 63 years. Among the patients, 71% were women and their mean age was 84 years. The results of factor analysis indicated that the scale was unidimensional. Cronbach’s α was 0.73. Not having a good relationship before caregiving was associated with significantly worse family dynamics scores, as was greater dependence regarding ADL. Conclusions We developed a scale that enables physicians to assess the dynamics of families with a patient and a family caregiver. The scale’s scores are reliable and the results of validation testing were generally good. This scale holds promise as a

  13. 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.

  14. Large-scale fractures related to inception of the Yellowstone hotspot

    USGS Publications Warehouse

    Glen, J.M.G.; Ponce, D.A.

    2002-01-01

    During middle Miocene time, western North America was subject to flood-basalt volcanism, dike-swarm injection, and broad-scale fracturing and folding of the crust. We propose a simple model to account for these events and for a regional pattern of geologic and geophysical features. Aeromagnetic maps reveal some of the most important elements of this pattern, which are several narrow, arcuate anomalies, here referred to as the Northern Nevada rifts. These rifts extend hundreds of kilometers across Nevada and are likely caused by highly magnetic, middle Miocene mafic dikes. With the aid of filtering techniques, the anomalies can be traced into Oregon. Together with other geologic features, such as fold axes, dike swarms, and faults, they produce a spoke-like pattern fanning over 220?? of arc that converges toward a point near the Oregon-Idaho border (lat ~44??N). A possible cause for this pattern is a point source of stress at the base of the crust related to the formation of the Yellowstone hotspot. The spoke-like pattern, however, does not persist at large distances from the emerging hotspot; several hundred kilometers to the south, the Northern Nevada rifts deviate significantly (>30??) from a radial trend. We show that a simple model-imposing a point source of stress at the base of the crust and a regional stress field aligned with the presumed middle Miocene stress direction-fits the observed fracture pattern. It thus accounts for both the radial pattern present near the nascent hotspot and the far-field pattern due to regional stresses.

  15. Measurement of Galaxy Cluster Integrated Comptonization and Mass Scaling Relations with the South Pole Telescope

    SciTech Connect

    Saliwanchik, B. R.; et al.

    2015-01-22

    We describe a method for measuring the integrated Comptonization (Y (SZ)) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in the South Pole Telescope (SPT) data. We use a Markov Chain Monte Carlo method to fit a β-model source profile and integrate Y (SZ) within an angular aperture on the sky. In simulated observations of an SPT-like survey that include cosmic microwave background anisotropy, point sources, and atmospheric and instrumental noise at typical SPT-SZ survey levels, we show that we can accurately recover β-model parameters for inputted clusters. We measure Y (SZ) for simulated semi-analytic clusters and find that Y (SZ) is most accurately determined in an angular aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure Y (SZ) and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring Y (SZ) within a 0.'75 radius aperture, we find an intrinsic log-normal scatter of 21% ± 11% in Y (SZ) at a fixed mass. Measuring Y (SZ) within a 0.3 Mpc projected radius (equivalent to 0.'75 at the survey median redshift z = 0.6), we find a scatter of 26% ± 9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters that Y (SZ) measured within an aperture comparable to the SPT beam size is equivalent