Size, shape and flow characterization of ground wood chip and ground wood pellet particles

DOE PAGES

Rezaei, Hamid; Lim, C. Jim; Lau, Anthony; ...

2016-07-11

Size, shape and density of biomass particles influence their transportation, fluidization, rates of drying and thermal decomposition. Pelleting wood particles increases the particle density and reduces the variability of physical properties among biomass particles. In this study, pine chips prepared for pulping and commercially produced pine pellets were ground in a hammer mill using grinder screens of 3.2, 6.3, 12.7 and 25.4mmperforations. Pellets consumed about 7 times lower specific grinding energy than chips to produce the same size of particles. Grinding pellets produced the smaller particles with narrower size distribution than grinding chips. Derived shape factors in digital image analysismore » showed that chip particles were rectangular and had the aspect ratios about one third of pellet particles. Pellet particles were more circular shape. The mechanical sieving underestimated the actual particle size and did not represent the size of particles correctly. Instead, digital imaging is preferred. Angle of repose and compressibility tests represented the flow properties of ground particles. Pellet particles made a less compacted bulk, had lower cohesion and did flow easier in a pile of particles. In conclusion, particle shape affected the flow properties more than particle size« less

Axially adjustable magnetic properties in arrays of multilayered Ni/Cu nanowires with variable segment sizes

NASA Astrophysics Data System (ADS)

Shirazi Tehrani, A.; Almasi Kashi, M.; Ramazani, A.; Montazer, A. H.

2016-07-01

Arrays of multilayered Ni/Cu nanowires (NWs) with variable segment sizes were fabricated into anodic aluminum oxide templates using a pulsed electrodeposition method in a single bath for designated potential pulse times. Increasing the pulse time between 0.125 and 2 s in the electrodeposition of Ni enabled the formation of segments with thicknesses ranging from 25 to 280 nm and 10-110 nm in 42 and 65 nm diameter NWs, respectively, leading to disk-shaped, rod-shaped and/or near wire-shaped geometries. Using hysteresis loop measurements at room temperature, the axial and perpendicular magnetic properties were investigated. Regardless of the segment geometry, the axial coercivity and squareness significantly increased with increasing Ni segment thickness, in agreement with a decrease in calculated demagnetizing factors along the NW length. On the contrary, the perpendicular magnetic properties were found to be independent of the pulse times, indicating a competition between the intrawire interactions and the shape demagnetizing field.

Some Causes of the Variable Shape of Flocks of Birds

PubMed Central

Hemelrijk, Charlotte K.; Hildenbrandt, Hanno

2011-01-01

Flocks of birds are highly variable in shape in all contexts (while travelling, avoiding predation, wheeling above the roost). Particularly amazing in this respect are the aerial displays of huge flocks of starlings (Sturnus vulgaris) above the sleeping site at dawn. The causes of this variability are hardly known, however. Here we hypothesise that variability of shape increases when there are larger local differences in movement behaviour in the flock. We investigate this hypothesis with the help of a model of the self-organisation of travelling groups, called StarDisplay, since such a model has also increased our understanding of what causes the oblong shape of schools of fish. The flocking patterns in the model prove to resemble those of real birds, in particular of starlings and rock doves. As to shape, we measure the relative proportions of the flock in several ways, which either depend on the direction of movement or do not. We confirm that flock shape is usually more variable when local differences in movement in the flock are larger. This happens when a) flock size is larger, b) interacting partners are fewer, c) the flock turnings are stronger, and d) individuals roll into the turn. In contrast to our expectations, when variability of speed in the flock is higher, flock shape and the positions of members in the flock are more static. We explain this and indicate the adaptive value of low variability of speed and spatial restriction of interaction and develop testable hypotheses. PMID:21829627

Geometric morphometric analysis of Colombian Anopheles albimanus (Diptera: Culicidae) reveals significant effect of environmental factors on wing traits and presence of a metapopulation

PubMed Central

Gómez, Giovan F.; Márquez, Edna J.; Gutiérrez, Lina A.; Conn, Jan E.; Correa, Margarita M.

2015-01-01

Anopheles albimanus is a major malaria mosquito vector in Colombia. In the present study, wing variability (size and shape) in An. albimanus populations from Colombian Maracaibo and Chocó bio-geographical eco-regions and the relationship of these phenotypic traits with environmental factors were evaluated. Microsatellite and morphometric data facilitated a comparison of the genetic and phenetic structure of this species. Wing size was influenced by elevation and relative humidity, whereas wing shape was affected by these two variables and also by rainfall, latitude, temperature and eco-region. Significant differences in mean shape between populations and eco-regions were detected, but they were smaller than those at the intra-population level. Correct assignment based on wing shape was low at the population level (<58%) and only slightly higher (>70%) at the eco-regional level, supporting the low population structure inferred from microsatellite data. Wing size was similar among populations with no significant differences between eco-regions. Population relationships in the genetic tree did not agree with those from the morphometric data; however, both datasets consistently reinforced a panmictic population of An. albimanus. Overall, site-specific population differentiation is not strongly supported by wing traits or genotypic data. We hypothesize that the metapopulation structure of An. albimanus throughout these Colombian eco-regions is favoring plasticity in wing traits, a relevant characteristic of species living under variable environmental conditions and colonizing new habitats. PMID:24704285

Rhodnius prolixus and Rhodnius robustus-like (Hemiptera, Reduviidae) wing asymmetry under controlled conditions of population density and feeding frequency.

PubMed

Márquez, E J; Saldamando-Benjumea, C I

2013-09-01

Habitat change in Rhodnius spp may represent an environmental challenge for the development of the species, particularly when feeding frequency and population density vary in nature. To estimate the effect of these variables in stability on development, the degree of directional asymmetry (DA) and fluctuating asymmetry (FA) in the wing size and shape of R. prolixus and R. robustus-like were measured under laboratory controlled conditions. DA and FA in wing size and shape were significant in both species, but their variation patterns showed both inter-specific and sexual dimorphic differences in FA of wing size and shape induced by nutrition stress. These results suggest different abilities of the genotypes and sexes of two sylvatic and domestic genotypes of Rhodnius to buffer these stress conditions. However, both species showed non-significant differences in the levels of FA between treatments that simulated sylvan vs domestic conditions, indicating that the developmental noise did not explain the variation in wing size and shape found in previous studies. Thus, this result confirm that the variation in wing size and shape in response to treatments constitute a plastic response of these genotypes to population density and feeding frequency.

A revision of chiggers of the minuta species-group (Acari: Trombiculidae: Neotrombicula Hirst, 1925) using multivariate morphometrics.

PubMed

Stekolnikov, Alexandr A; Klimov, Pavel B

2010-09-01

We revise chiggers belonging to the minuta-species group (genus Neotrombicula Hirst, 1925) from the Palaearctic using size-free multivariate morphometrics. This approach allowed us to resolve several diagnostic problems. We show that the widely distributed Neotrombicula scrupulosa Kudryashova, 1993 forms three spatially and ecologically isolated groups different from each other in size or shape (morphometric property) only: specimens from the Caucasus are distinct from those from Asia in shape, whereas the Asian specimens from plains and mountains are different from each other in size. We developed a multivariate classification model to separate three closely related species: N. scrupulosa, N. lubrica Kudryashova, 1993 and N. minuta Schluger, 1966. This model is based on five shape variables selected from an initial 17 variables by a best subset analysis using a custom size-correction subroutine. The variable selection procedure slightly improved the predictive power of the model, suggesting that it not only removed redundancy but also reduced 'noise' in the dataset. The overall classification accuracy of this model is 96.2, 96.2 and 95.5%, as estimated by internal validation, external validation and jackknife statistics, respectively. Our analyses resulted in one new synonymy: N. dimidiata Stekolnikov, 1995 is considered to be a synonym of N. lubrica. Both N. scrupulosa and N. lubrica are recorded from new localities. A key to species of the minuta-group incorporating results from our multivariate analyses is presented.

Sex determination by three-dimensional geometric morphometrics of craniofacial form.

PubMed

Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K

The purpose of the present study is to define which regions of the cranium, the upper-face, the orbits and the nasal are the most sexually dimorphic, by using three-dimensional geometric morphometric methods, and investigate the effectiveness of this method in determining sex from the shape of these regions. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived in Greece during the 20(th) century. The three-dimensional co-ordinates of 31 ecto-cranial landmarks were digitized using a MicroScribe 3DX contact digitizer. Goodall's F-test was performed in order to compare statistical differences in shape between males and females. Generalized Procrustes Analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, Size and Form analyses were carried out by logistic regression and discriminant function analysis. The results indicate that there are shape differences between the sexes in the upper-face and the orbits. The highest shape classification rate was obtained from the upper-face region. The centroid size of the caraniofacial and the orbital regions was smaller in females than males. Moreover, it was found that size is significant for sexual dimorphism in the upper-face region. As anticipated, the classification accuracy improves when both size and shape are combined. The findings presented here constitute a firm basis upon which further research can be conducted.

Effect of Test Specimen Shape and Size on Interlaminar Tensile Properties of Advanced Carbon-Carbon Composites

NASA Technical Reports Server (NTRS)

Vaughn, Wallace L.

2015-01-01

The interlaminar tensile strength of 1000-tow T-300 fiber ACC-6 carbon-carbon composites was measured using the method of bonding the coupons to adherends at room temperature. The size, 0.70 to 1.963 inches maximum width or radius, and shape, round or square, of the test coupons were varied to determine if the test method was sensitive to these variables. Sixteen total variations were investigated and the results modeled.

Size- and shape-dependent surface thermodynamic properties of nanocrystals

NASA Astrophysics Data System (ADS)

Fu, Qingshan; Xue, Yongqiang; Cui, Zixiang

2018-05-01

As the fundamental properties, the surface thermodynamic properties of nanocrystals play a key role in the physical and chemical changes. However, it remains ambiguous about the quantitative influence regularities of size and shape on the surface thermodynamic properties of nanocrystals. Thus by introducing interface variables into the Gibbs energy and combining Young-Laplace equation, relations between the surface thermodynamic properties (surface Gibbs energy, surface enthalpy, surface entropy, surface energy and surface heat capacity), respectively, and size of nanocrystals with different shapes were derived. Theoretical estimations of the orders of the surface thermodynamic properties of nanocrystals agree with available experimental values. Calculated results of the surface thermodynamic properties of Au, Bi and Al nanocrystals suggest that when r > 10 nm, the surface thermodynamic properties linearly vary with the reciprocal of particle size, and when r < 10 nm, the effect of particle size on the surface thermodynamic properties becomes greater and deviates from linear variation. For nanocrystals with identical equivalent diameter, the more the shape deviates from sphere, the larger the surface thermodynamic properties (absolute value) are.

Body shape indices are predictors for estimating fat-free mass in male athletes

PubMed Central

Aoki, Toru; Komori, Daisuke; Oyamada, Kazuyuki; Murata, Kensuke; Fujita, Eiji; Akamine, Takuya; Urita, Yoshihisa; Yamamoto, Masayoshi

2018-01-01

It is unknown whether body size and body shape parameters can be predictors for estimating whole body fat-free mass (FFM) in male athletes. This study aimed to investigate whether body size and shape variables can be predictors for FFM in male athletes. Using a whole-body dual-energy X-ray absorptiometry scanner, whole body fat mass (FM) and FFM were determined in 132 male athletes and 14 sedentary males. The sample was divided into two groups: validation (N = 98) and cross-validation (N = 48) groups. Body height (BH), body mass (BM), and waist circumference at immediately above the iliac crest (W) were measured. BM-to-W and W-to-BH ratios were calculated as indices of body shapes. Stepwise multiple regression analysis revealed that BM/W and W/BH were selected as explainable variables for predicting FFM. The equation developed in the validation group was FFM (kg) = 0.883 × BM/W (kg/m) + 43.674 × W/BH (cm/cm)– 41.480 [R2 = 0.900, SEE (%SEE) = 2.3 kg (3.8%)], which was validated in the cross-validation group. Thus, the current results demonstrate that an equation using BM/W and W/BH as independent variables is applicable for predicting FFM in male athletes. PMID:29346452

Specific-age group sex estimation of infants through geometric morphometrics analysis of pubis and ischium.

PubMed

Estévez Campo, Enrique José; López-Lázaro, Sandra; López-Morago Rodríguez, Claudia; Alemán Aguilera, Inmaculada; Botella López, Miguel Cecilio

2018-05-01

Sex determination of unknown individuals is one of the primary goals of Physical and Forensic Anthropology. The adult skeleton can be sexed using both morphological and metric traits on a large number of bones. The human pelvis is often used as an important element of adult sex determination. However, studies carried out about the pelvic bone in subadult individuals present several limitations due the absence of sexually dimorphic characteristics. In this study, we analyse the sexual dimorphism of the immature pubis and ischium bones, attending to their shape (Procrustes residuals) and size (centroid size), using an identified sample of subadult individuals composed of 58 individuals for the pubis and 83 for the ischium, aged between birth and 1year of life, from the Granada osteological collection of identified infants (Granada, Spain). Geometric morphometric methods and discriminant analysis were applied to this study. The results of intra- and inter-observer error showed good and excellent agreement in the location of coordinates of landmarks and semilandmarks, respectively. Principal component analysis performed on shape and size variables showed superposition of the two sexes, suggesting a low degree of sexual dimorphism. Canonical variable analysis did not show significant changes between the male and female shapes. As a consequence, discriminant analysis with leave-one-out cross validation provided low classification accuracy. The results suggested a low degree of sexual dimorphism supported by significant sexual dimorphism in the subadult sample and poor cross-validated classification accuracy. The inclusion of centroid size as a discriminant variable does not imply a significant improvement in the results of the analysis. The similarities found between the sexes prevent consideration of pubic and ischial morphology as a sex estimator in early stages of development. The authors suggest extending this study by analysing the different trajectories of shape and size in later ontogeny between males and females. Copyright © 2018 Elsevier B.V. All rights reserved.

Grid sensitivity capability for large scale structures

NASA Technical Reports Server (NTRS)

Nagendra, Gopal K.; Wallerstein, David V.

1989-01-01

The considerations and the resultant approach used to implement design sensitivity capability for grids into a large scale, general purpose finite element system (MSC/NASTRAN) are presented. The design variables are grid perturbations with a rather general linking capability. Moreover, shape and sizing variables may be linked together. The design is general enough to facilitate geometric modeling techniques for generating design variable linking schemes in an easy and straightforward manner. Test cases have been run and validated by comparison with the overall finite difference method. The linking of a design sensitivity capability for shape variables in MSC/NASTRAN with an optimizer would give designers a powerful, automated tool to carry out practical optimization design of real life, complicated structures.

Clones of cells switch from reduction to enhancement of size variability in Arabidopsis sepals

PubMed Central

Tsugawa, Satoru; Hervieux, Nathan; Kierzkowski, Daniel; Routier-Kierzkowska, Anne-Lise; Sapala, Aleksandra; Hamant, Olivier; Smith, Richard S.; Boudaoud, Arezki

2017-01-01

Organs form with remarkably consistent sizes and shapes during development, whereas a high variability in growth is observed at the cell level. Given this contrast, it is unclear how such consistency in organ scale can emerge from cellular behavior. Here, we examine an intermediate scale, the growth of clones of cells in Arabidopsis sepals. Each clone consists of the progeny of a single progenitor cell. At early stages, we find that clones derived from a small progenitor cell grow faster than those derived from a large progenitor cell. This results in a reduction in clone size variability, a phenomenon we refer to as size uniformization. By contrast, at later stages of clone growth, clones change their growth pattern to enhance size variability, when clones derived from larger progenitor cells grow faster than those derived from smaller progenitor cells. Finally, we find that, at early stages, fast growing clones exhibit greater cell growth heterogeneity. Thus, cellular variability in growth might contribute to a decrease in the variability of clones throughout the sepal. PMID:29183944

Representation and visualization of variability in a 3D anatomical atlas using the kidney as an example

NASA Astrophysics Data System (ADS)

Hacker, Silke; Handels, Heinz

2006-03-01

Computer-based 3D atlases allow an interactive exploration of the human body. However, in most cases such 3D atlases are derived from one single individual, and therefore do not regard the variability of anatomical structures concerning their shape and size. Since the geometric variability across humans plays an important role in many medical applications, our goal is to develop a framework of an anatomical atlas for representation and visualization of the variability of selected anatomical structures. The basis of the project presented is the VOXEL-MAN atlas of inner organs that was created from the Visible Human data set. For modeling anatomical shapes and their variability we utilize "m-reps" which allow a compact representation of anatomical objects on the basis of their skeletons. As an example we used a statistical model of the kidney that is based on 48 different variants. With the integration of a shape description into the VOXEL-MAN atlas it is now possible to query and visualize different shape variations of an organ, e.g. by specifying a person's age or gender. In addition to the representation of individual shape variants, the average shape of a population can be displayed. Besides a surface representation, a volume-based representation of the kidney's shape variants is also possible. It results from the deformation of the reference kidney of the volume-based model using the m-rep shape description. In this way a realistic visualization of the shape variants becomes possible, as well as the visualization of the organ's internal structures.

How well can body size represent effects of the environment on demographic rates? Disentangling correlated explanatory variables.

PubMed

Brooks, Mollie E; Mugabo, Marianne; Rodgers, Gwendolen M; Benton, Timothy G; Ozgul, Arpat

2016-03-01

Demographic rates are shaped by the interaction of past and current environments that individuals in a population experience. Past environments shape individual states via selection and plasticity, and fitness-related traits (e.g. individual size) are commonly used in demographic analyses to represent the effect of past environments on demographic rates. We quantified how well the size of individuals captures the effects of a population's past and current environments on demographic rates in a well-studied experimental system of soil mites. We decomposed these interrelated sources of variation with a novel method of multiple regression that is useful for understanding nonlinear relationships between responses and multicollinear explanatory variables. We graphically present the results using area-proportional Venn diagrams. Our novel method was developed by combining existing methods and expanding upon them. We showed that the strength of size as a proxy for the past environment varied widely among vital rates. For instance, in this organism with an income breeding life history, the environment had more effect on reproduction than individual size, but with substantial overlap indicating that size encompassed some of the effects of the past environment on fecundity. This demonstrates that the strength of size as a proxy for the past environment can vary widely among life-history processes within a species, and this variation should be taken into consideration in trait-based demographic or individual-based approaches that focus on phenotypic traits as state variables. Furthermore, the strength of a proxy will depend on what state variable(s) and what demographic rate is being examined; that is, different measures of body size (e.g. length, volume, mass, fat stores) will be better or worse proxies for various life-history processes. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Immobilization thresholds of electrofishing relative to fish size

USGS Publications Warehouse

Dolan, C.R.; Miranda, L.E.

2003-01-01

Fish size and electrical waveforms have frequently been associated with variation in electrofishing effectiveness. Under controlled laboratory conditions, we measured the electrical power required by five electrical waveforms to immobilize eight fish species of diverse sizes and shapes. Fish size was indexed by total body length, surface area, volume, and weight; shape was indexed by the ratio of body length to body depth. Our objectives were to identify immobilization thresholds, elucidate the descriptors of fish size that were best associated with those immobilization thresholds, and determine whether the vulnerability of a species relative to other species remained constant across electrical treatments. The results confirmed that fish size is a key variable controlling the immobilization threshold and further suggested that the size descriptor best related to immobilization is fish volume. The peak power needed to immobilize fish decreased rapidly with increasing fish volume in small fish but decreased slowly for fish larger than 75-100 cm 3. Furthermore, when we controlled for size and shape, different waveforms did not favor particular species, possibly because of the overwhelming effect of body size. Many of the immobilization inconsistencies previously attributed to species might simply represent the effect of disparities in body size.

Quantitative 3D shape description of dust particles from treated seeds by means of X-ray micro-CT.

PubMed

Devarrewaere, Wouter; Foqué, Dieter; Heimbach, Udo; Cantre, Dennis; Nicolai, Bart; Nuyttens, David; Verboven, Pieter

2015-06-16

Crop seeds are often treated with pesticides before planting. Pesticide-laden dust particles can be abraded from the seed coating during planting and expelled into the environment, damaging nontarget organisms. Drift of these dust particles depends on their size, shape and density. In this work, we used X-ray micro-CT to examine the size, shape (sphericity) and porosity of dust particles from treated seeds of various crops. The dust properties quantified in this work were very variable in different crops. This variability may be a result of seed morphology, seed batch, treatment composition, treatment technology, seed cleaning or an interaction of these factors. The intraparticle porosity of seed treatment dust particles varied from 0.02 to 0.51 according to the crop and generally increased with particle size. Calculated settling velocities demonstrated that accounting for particle shape and porosity is important in drift studies. For example, the settling velocity of dust particles with an equivalent diameter of 200 μm may vary between 0.1 and 1.2 m s(-1), depending on their shape and density. Our analysis shows that in a wind velocity of 5 m s(-1), such particles ejected at 1 m height may travel between 4 and 50 m from the source before settling. Although micro-CT is a valuable tool to characterize dust particles, the current image processing methodology limits the number of particles that can be analyzed.

Grain Size as a Control for Melt Focusing Beneath Mid-Ocean Ridges

NASA Astrophysics Data System (ADS)

Turner, A.; Katz, R. F.; Behn, M. D.

2015-12-01

Grain size is a fundamental control on both the rheology and permeability of the mantle. These properties, in turn, affect the transport of melt beneath mid-ocean ridges. Previous models of grain size beneath ridges have considered only the single-phase problem of dynamic recrystallisation and the resultant pattern of grain-size variation [1,2]. These models have not coupled the spatially variable grain-size field to two-phase (partially molten) mechanics to investigate the implications of spatially variable grain size on melt transport. Here, we present new results from numerical models that investigate the consequences of this coupling. In our two-dimensional, two-phase model the grain-size is coupled to both the permeability and rheology. The rheology is strain-rate and grain-size dependent. For simplicity, however, the grain-size field is not computed dynamically — rather, it is imposed from a single-phase, steady-state model [1] that is based on the "wattmeter" theory [3]. Our calculations predicts that a spatially variable grain size field can promote focusing of melt towards the ridge axis. This focusing is distinct from the commonly discussed, sub-lithospheric decompaction channel [4]. Furthermore, our model predicts that the shape of the partially molten region is sensitive to rheological parameters associated with grain size. The comparison of this shape with observations [5] may help to constrain the rheology of the upper mantle beneath mid-ocean ridges. References: [1] Turner et al., Geochem. Geophys. Geosyst., 16, 925-946, 2015. [2] Behn et al., EPSL, 282, 178-189, 2009. [3] Austin and Evans, Geology, 35:343-346, 2007. [4] Sparks and Parmentier, EPSL, 105, 368-377, 1991. [5] Key et al., Nature, 495, 499-502, 2013.

The morphology of human hyoid bone in relation to sex, age and body proportions.

PubMed

Urbanová, P; Hejna, P; Zátopková, L; Šafr, M

2013-06-01

Morphological aspects of the human hyoid bone are, like many other skeletal elements in human body, greatly affected by individual's sex, age and body proportions. Still, the known sex-dependent bimodality of a number of body size characteristics overshadows the true within-group patterns. Given the ambiguity of the causal effects of age, sex and body size upon hyoid morphology the present study puts the relationship between shape of human hyoid bone and body proportions (height and weight) under scrutiny of a morphological study. Using 211 hyoid bones and landmark-based methods of geometric morphometrics, it was shown that the size of hyoid bones correlated positively with measured body dimensions but showed no correlation if the individual's sex was controlled for. For shape variables, our results revealed that hyoid morphology is clearly related to body size as expressed in terms of the height and weight. Yet, the hyoid shape was shown to result primarily from the sex-related bimodal distribution of studied body size descriptors which, in the case of the height-dependent model, exhibited opposite trends for males and females. Apart from the global hyoid shape given by spatial arrangements of the greater horns, body size dependency was translated into size and position of the hyoid body. None of the body size characters had any impact on hyoid asymmetry. Ultimately, sexually dimorphic variation was revealed for age-dependent changes in both size and shape of hyoid bones as male hyoids tend to be more susceptible to modifications with age than female bones. Copyright © 2013 Elsevier GmbH. All rights reserved.

PROGRESS ON THE STUDY OF BETA TREATMENT OF URANIUM, AUGUST 1, 1961-NOVEMBER 30, 1961

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, R.B.; Wolff, A.K.

Variables affecting the texture and grain size of uranium during beta treatment are summarized. The effects of composition (ingot versus dingot), prior delta condition, prior texture, pre-quenching air delay, rod or tube size, quenching medium and applied stress on grain size, distontion, and G/sub 3/ gradients in the final beta-treated shapes are described. (N.W.R.)

Effects of Missing Data Methods in SEM under Conditions of Incomplete and Nonnormal Data

ERIC Educational Resources Information Center

Li, Jian; Lomax, Richard G.

2017-01-01

Using Monte Carlo simulations, this research examined the performance of four missing data methods in SEM under different multivariate distributional conditions. The effects of four independent variables (sample size, missing proportion, distribution shape, and factor loading magnitude) were investigated on six outcome variables: convergence rate,…

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis

PubMed Central

Ichikawa, Kei; Tanaka, Yoshiki; Kato, Yukihito; Horai, Rie; Tamaoki, Akeno; Ichikawa, Kazuo

2017-01-01

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces. PMID:28210504

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis.

PubMed

Takagi, Mari; Kojima, Takashi; Ichikawa, Kei; Tanaka, Yoshiki; Kato, Yukihito; Horai, Rie; Tamaoki, Akeno; Ichikawa, Kazuo

2017-01-01

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.

Prechamber Compression-Ignition Engine Performance

NASA Technical Reports Server (NTRS)

Moore, Charles S; Collins, John H , Jr

1938-01-01

Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

The evolution of cranial base and face in Cercopithecoidea and Hominoidea: Modularity and morphological integration.

PubMed

Profico, Antonio; Piras, Paolo; Buzi, Costantino; Di Vincenzo, Fabio; Lattarini, Flavio; Melchionna, Marina; Veneziano, Alessio; Raia, Pasquale; Manzi, Giorgio

2017-12-01

The evolutionary relationship between the base and face of the cranium is a major topic of interest in primatology. Such areas of the skull possibly respond to different selective pressures. Yet, they are often said to be tightly integrated. In this paper, we analyzed shape variability in the cranial base and the facial complex in Cercopithecoidea and Hominoidea. We used a landmark-based approach to single out the effects of size (evolutionary allometry), morphological integration, modularity, and phylogeny (under Brownian motion) on skull shape variability. Our results demonstrate that the cranial base and the facial complex exhibit different responses to different factors, which produces a little degree of morphological integration between them. Facial shape variation appears primarily influenced by body size and sexual dimorphism, whereas the cranial base is mostly influenced by functional factors. The different adaptations affecting the two modules suggest they are best studied as separate and independent units, and that-at least when dealing with Catarrhines-caution must be posed with the notion of strong cranial integration that is commonly invoked for the evolution of their skull shape. © 2017 Wiley Periodicals, Inc.

The A and m coefficients in the Bruun/Dean equilibrium profile equation seen from the Arctic

USGS Publications Warehouse

Are, F.; Reimnitz, E.

2008-01-01

The Bruun/Dean relation between water depth and distance from the shore with a constant profile shape factor is widely used to describe shoreface profiles in temperate environments. However, it has been shown that the sediment scale parameter (A) and the profile shape factor (m) are interrelated variables. An analysis of 63 Arctic erosional shoreface profiles shows that both coefficients are highly variable. Relative frequency of the average m value is only 16% by the class width 0.1. No other m value frequency exceeds 21%. Therefore, there is insufficient reason to use average m to characterize Arctic shoreface profile shape. The shape of each profile has a definite combination of A and m values. Coefficients A and m show a distinct inverse relationship, as in temperate climate. A dependence of m values on coastal sediment grain size is seen, and m decreases with increasing grain size. With constant m = 0.67, parameter A obtains a dimension unit m1/3. But A equals the water depth in meters 1 m from the water edge. This fact and the variability of parameter m testify that the Bruun/Dean equation is essentially an empirical formula. There is no need to give any measurement unit to parameter A. But the International System of Units (SI) has to be used in applying the Bruun/Dean equation for shoreface profiles. A comparison of the shape of Arctic shoreface profiles with those of temperate environments shows surprising similarity. Therefore, the conclusions reached in this Arctic paper seem to apply also to temperate environments.

Form drag in rivers due to small-scale natural topographic features: 2. Irregular sequences

USGS Publications Warehouse

Kean, J.W.; Smith, J.D.

2006-01-01

The size, shape, and spacing of small-scale topographic features found on the boundaries of natural streams, rivers, and floodplains can be quite variable. Consequently, a procedure for determining the form drag on irregular sequences of different-sized topographic features is essential for calculating near-boundary flows and sediment transport. A method for carrying out such calculations is developed in this paper. This method builds on the work of Kean and Smith (2006), which describes the flow field for the simpler case of a regular sequence of identical topographic features. Both approaches model topographic features as two-dimensional elements with Gaussian-shaped cross sections defined in terms of three parameters. Field measurements of bank topography are used to show that (1) the magnitude of these shape parameters can vary greatly between adjacent topographic features and (2) the variability of these shape parameters follows a lognormal distribution. Simulations using an irregular set of topographic roughness elements show that the drag on an individual element is primarily controlled by the size and shape of the feature immediately upstream and that the spatial average of the boundary shear stress over a large set of randomly ordered elements is relatively insensitive to the sequence of the elements. In addition, a method to transform the topography of irregular surfaces into an equivalently rough surface of regularly spaced, identical topographic elements also is given. The methods described in this paper can be used to improve predictions of flow resistance in rivers as well as quantify bank roughness.

Sex determination by three-dimensional geometric morphometrics of the palate and cranial base.

PubMed

Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K

2013-01-01

The purpose of this study is to assess sexual dimorphism in the palate and base of adult crania using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 30 ectocranial landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes Analysis (GPA) was used to obtain size and shape variables for statistical analysis. Three discriminant function analyses were carried out: (1) using PC scores from Procrustes shape space, (2) centroid size alone, and (3) PC scores of GPA residuals which includes InCS for analysis in Procrustes form space. Results indicate that there are shape differences between sexes. In males, the palate is deepest and more elongated; the cranial base is shortened. Sex-specific shape differences for the cross-validated data give better classification results in the cranial base (77.2%) compared with the palate (68.9%). Size alone yielded better results for cranial base (82%) in opposition to palate (63.1%). As anticipated, the classification accuracy improves when both size and shape are combined (90.4% for cranial base, and 74.8% for palate).

Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments.

PubMed

Ninan, Elizabeth; Berzins, David W

2013-01-01

Recently introduced into the market are shape memory nickel-titanium (NiTi) rotary files. The objective of this study was to investigate the torsion and bending properties of shape memory files (CM Wire, HyFlex CM, and Phoenix Flex) and compare them with conventional (ProFile ISO and K3) and M-Wire (GT Series X and ProFile Vortex) NiTi files. Sizes 20, 30, and 40 (n = 12/size/taper) of 0.02 taper CM Wire, Phoenix Flex, K3, and ProFile ISO and 0.04 taper HyFlex CM, ProFile ISO, GT Series X, and Vortex were tested in torsion and bending per ISO 3630-1 guidelines by using a torsiometer. All data were statistically analyzed by analysis of variance and the Tukey-Kramer test (P = .05) to determine any significant differences between the files. Significant interactions were present among factors of size and file. Variability in maximum torque values was noted among the shape memory files brands, sometimes exhibiting the greatest or least torque depending on brand, size, and taper. In general, the shape memory files showed a high angle of rotation before fracture but were not statistically different from some of the other files. However, the shape memory files were more flexible, as evidenced by significantly lower bending moments (P < .008). Shape memory files show greater flexibility compared with several other NiTi rotary file brands. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Intraspecific variation in body size and shape in an andean highland anole species, Anolis ventrimaculatus (Squamata: Dactyloidae).

PubMed

Calderón-Espinosa, Martha L; Ortega-León, Angela M; Zamora-Abrego, Joan G

2013-03-01

Variation in body characteristics related to lizard locomotion has been poorly studied at the intraspecific level in Anolis species. Local adaptation due to habitat heterogeneity has been reported in some island species. However, studies of mainland species are particularly scarce and suggest different patterns: high variability among highland lizards and poorly differentiated populations in one Amazonian species. We characterized inter population variation of body size and shape in the highland Andean Anolis ventrimaculatus, an endemic species from Western Colombia. A total of 15 morphometric variables were measured in specimens from the reptile collection of the Instituto de Ciencias Naturales, Universidad Nacional, Colombia. The study included individuals from seven different highland localities. We found size and shape sexual dimorphism, both of which varied among localities. Patterns of variation in body proportions among populations were different in both males and females, suggesting that either sexual or natural selective factors are different in each locality and between sexes. Since this species exhibits a fragmented distribution in highlands, genetic divergence may also be a causal factor of the observed variation. Ecological, behavioral, additional morphological as well as phylogenetic data, may help to understand the evolutionary processes behind the geographic patterns found in this species.

Evaluation of removal of the size effect using data scaling and elliptic Fourier descriptors in otolith shape analysis, exemplified by the discrimination of two yellow croaker stocks along the Chinese coast

NASA Astrophysics Data System (ADS)

Zhao, Bo; Liu, Jinhu; Song, Junjie; Cao, Liang; Dou, Shuozeng

2017-11-01

Removal of the length effect in otolith shape analysis for stock identification using length scaling is an important issue; however, few studies have attempted to investigate the effectiveness or weakness of this methodology in application. The aim of this study was to evaluate whether commonly used size scaling methods and normalized elliptic Fourier descriptors (NEFDs) could effectively remove the size effect of fish in stock discrimination. To achieve this goal, length groups from two known geographical stocks of yellow croaker, Larimichthys polyactis, along the Chinese coast (five groups from the Changjiang River estuary of the East China Sea and three groups from the Bohai Sea) were subjected to otolith shape analysis. The results indicated that the variation of otolith shape caused by intra-stock fish length might exceed that due to inter-stock geographical separation, even when otolith shape variables are standardized with length scaling methods. This variation could easily result in misleading stock discrimination through otolith shape analysis. Therefore, conclusions about fish stock structure should be carefully drawn from otolith shape analysis because the observed discrimination may primarily be due to length effects, rather than differences among stocks. The application of multiple methods, such as otoliths shape analysis combined with elemental fingering, tagging or genetic analysis, is recommended for sock identification.

[Morphological characterization of annatto fruits 9bixa orellana L.) and its correspondence with protein and isoenzym patterns].

PubMed

Medina, A M; Michelangeli, C; Ramis, C; Díaz, A

2001-01-01

A group of 32 annatto genotypes collected in five Venezuelan regions (Oriente, Centro, Llanos, Andes and Amazonas) and in Brazil were used for morphological studies. The fruit variables with the greatest discriminatory power in the formation of groups were capsule size, spinosity and seed size. On the other hand, an association group among the variables spinosity, spine length, dehiscence and apex shape were formed, also a proportional association between capsule and seed size, and between dehiscent capsule and brown coloured seeds. Additionally, in order to discriminate morphological variables behaviour in respond to electrophoretic variables, a group of protein and isozyme bands associated with fruit characteristics were established. Therefore, a classification system of this species was possible using morphological studies of the capsules, even though a determined association relating morphological and molecular patterns was not found.

High inter-specimen variability of baseline data for the tibio-talar contact area.

PubMed

Matricali, Giovanni A; Bartels, Ward; Labey, Luc; Dereymaeker, Greta Ph E; Luyten, Frank P; Vander Sloten, Jos

2009-01-01

The tibio-talar contact area has been widely investigated to monitor biomechanical changes due to articular incongruities or an altered loading. This study aims to investigate for the first time in a systematic way the extent of the inter-specimen variability of the tibio-talar contact area, and its repercussions when analyzing data concerning this parameter. Ten specimens were loaded to record the tibio-talar contact characteristics by use of pressure sensitive film. The size of the talar dome area, the size of the (normalized) tibio-talar contact area, the position of the tibio-talar contact area, and the shape of the latter were determined and analyzed. Inter-specimen variability was expressed as the coefficient of variation and was calculated for the datasets of previous studies as well. The size of the tibio-talar contact area showed a very high inter-specimen variability, as is the case in previous studies. This high variability persisted when a normalized tibio-talar contact area was calculated. The shape of the tibio-talar contact area showed some basic characteristics, but a high variation in details could be observed. Every specimen can be considered to have its own "ankle print". By this variability, articular incongruities are expected to have a different effect on local biomechanical characteristics in every single individual. Therefore, every single case has to be evaluated and reported for significant changes. In case of modeling, this also underscores the need to use subject specific models fed by sets of parameters derived from a series of single specimens.

Evaluation of bovine hemimandible morphology by means of elliptic Fourier descriptors.

PubMed

Parés-Casanova, Pere M

2014-01-01

The aim of this research was to compare size (area) and shape variations of bovine hemimandibles according to age. Digital photographs were obtained for 34 hemimandibles belonging to different European breeds of cattle. The specimens were classified according to age, as determined by molar eruption: b months ("young", M1 erupting, n = 8), 10 months ("immature", M2 erupting, n = 9) and over 24 months ("adult", M3 fully erupted, n = 17). Captured images were then digitally analysed based on elliptic Fourier descriptors, which mathematically characterise the area and shape. Hemimandibular areas only showed significant differences between the adults (2752.3 cm2 +/- 250.4) and young subjects (2373.8 cm2 +/- 300.2). The areas for each age group were not linked to linear shape modifications, which was the same for all age groups. So, bovine hemimandibular form change is mainly related to size changes. Shape variability is centred on the condylar ramus.

Realistic weight perception and body size assessment in a racially diverse community sample of dieters.

PubMed

Cachelin, F M; Striegel-Moore, R H; Elder, K A

1998-01-01

Recently, a shift in obesity treatment away from emphasizing ideal weight loss goals to establishing realistic weight loss goals has been proposed; yet, what constitutes "realistic" weight loss for different populations is not clear. This study examined notions of realistic shape and weight as well as body size assessment in a large community-based sample of African-American, Asian, Hispanic, and white men and women. Participants were 1893 survey respondents who were all dieters and primarily overweight. Groups were compared on various variables of body image assessment using silhouette ratings. No significant race differences were found in silhouette ratings, nor in perceptions of realistic shape or reasonable weight loss. Realistic shape and weight ratings by both women and men were smaller than current shape and weight but larger than ideal shape and weight ratings. Compared with male dieters, female dieters considered greater weight loss to be realistic. Implications of the findings for the treatment of obesity are discussed.

Phylogenetic, ecological, and allometric correlates of cranial shape in Malagasy lemuriforms.

PubMed

Baab, Karen L; Perry, Jonathan M G; Rohlf, F James; Jungers, William L

2014-05-01

Adaptive radiations provide important insights into many aspects of evolution, including the relationship between ecology and morphological diversification as well as between ecology and speciation. Many such radiations include divergence along a dietary axis, although other ecological variables may also drive diversification, including differences in diel activity patterns. This study examines the role of two key ecological variables, diet and activity patterns, in shaping the radiation of a diverse clade of primates, the Malagasy lemurs. When phylogeny was ignored, activity pattern and several dietary variables predicted a significant proportion of cranial shape variation. However, when phylogeny was taken into account, only typical diet accounted for a significant proportion of shape variation. One possible explanation for this discrepancy is that this radiation was characterized by a relatively small number of dietary shifts (and possibly changes in body size) that occurred in conjunction with the divergence of major clades. This pattern may be difficult to detect with the phylogenetic comparative methods used here, but may characterize not just lemurs but other mammals. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Variable-Size Bead Layer as Standard Reference for Endothelial Microscopes.

PubMed

Tufo, Simona; Prazzoli, Erica; Ferraro, Lorenzo; Cozza, Federica; Borghesi, Alessandro; Tavazzi, Silvia

2017-02-01

For morphometric analysis of the cell mosaic of corneal endothelium, checking accuracy and precision of instrumentation is a key step. In this study, a standard reference sample is proposed, developed to reproduce the cornea with its shape and the endothelium with its intrinsic variability in the cell size. A polystyrene bead layer (representing the endothelium) was deposited on a lens (representing the cornea). Bead diameters were 20, 25, and 30 μm (fractions in number 55%, 30%, and 15%, respectively). Bead density and hexagonality were simulated to obtain the expected true values and measured using a slit-lamp endothelial microscope applied to 1) a Takagi 700GL slit lamp at 40× magnification (recommended standard setup) and 2) a Takagi 2ZL slit lamp at 25× magnification. The simulation provided the expected bead density 2001 mm and hexagonality 47%. At 40×, density and hexagonality were measured to be 2009 mm (SD 93 mm) and 45% (SD 3%). At 25× on a different slit lamp, the comparison between measured and expected densities provided the factor 1.526 to resize the image and to use the current algorithms of the slit-lamp endothelial microscope for cell recognition. A variable-size polystyrene bead layer on a lens is proposed as a standard sample mimicking the real shape of the cornea and the variability of cell size and cell arrangement of corneal endothelium. The sample is suggested to evaluate accuracy and precision of cell density and hexagonality obtained by different endothelial microscopes, including a slit-lamp endothelial microscope applied to different slit lamps, also at different magnifications.

Time-dependent breakdown of fiber networks: Uncertainty of lifetime

NASA Astrophysics Data System (ADS)

Mattsson, Amanda; Uesaka, Tetsu

2017-05-01

Materials often fail when subjected to stresses over a prolonged period. The time to failure, also called the lifetime, is known to exhibit large variability of many materials, particularly brittle and quasibrittle materials. For example, a coefficient of variation reaches 100% or even more. Its distribution shape is highly skewed toward zero lifetime, implying a large number of premature failures. This behavior contrasts with that of normal strength, which shows a variation of only 4%-10% and a nearly bell-shaped distribution. The fundamental cause of this large and unique variability of lifetime is not well understood because of the complex interplay between stochastic processes taking place on the molecular level and the hierarchical and disordered structure of the material. We have constructed fiber network models, both regular and random, as a paradigm for general material structures. With such networks, we have performed Monte Carlo simulations of creep failure to establish explicit relationships among fiber characteristics, network structures, system size, and lifetime distribution. We found that fiber characteristics have large, sometimes dominating, influences on the lifetime variability of a network. Among the factors investigated, geometrical disorders of the network were found to be essential to explain the large variability and highly skewed shape of the lifetime distribution. With increasing network size, the distribution asymptotically approaches a double-exponential form. The implication of this result is that, so-called "infant mortality," which is often predicted by the Weibull approximation of the lifetime distribution, may not exist for a large system.

The role of environmental variables in structuring landscape-scale species distributions in seafloor habitats.

PubMed

Kraan, Casper; Aarts, Geert; Van der Meer, Jaap; Piersma, Theunis

2010-06-01

Ongoing statistical sophistication allows a shift from describing species' spatial distributions toward statistically disentangling the possible roles of environmental variables in shaping species distributions. Based on a landscape-scale benthic survey in the Dutch Wadden Sea, we show the merits of spatially explicit generalized estimating equations (GEE). The intertidal macrozoobenthic species, Macoma balthica, Cerastoderma edule, Marenzelleria viridis, Scoloplos armiger, Corophium volutator, and Urothoe poseidonis served as test cases, with median grain-size and inundation time as typical environmental explanatory variables. GEEs outperformed spatially naive generalized linear models (GLMs), and removed much residual spatial structure, indicating the importance of median grain-size and inundation time in shaping landscape-scale species distributions in the intertidal. GEE regression coefficients were smaller than those attained with GLM, and GEE standard errors were larger. The best fitting GEE for each species was used to predict species' density in relation to median grain-size and inundation time. Although no drastic changes were noted compared to previous work that described habitat suitability for benthic fauna in the Wadden Sea, our predictions provided more detailed and unbiased estimates of the determinants of species-environment relationships. We conclude that spatial GEEs offer the necessary methodological advances to further steps toward linking pattern to process.

A Differential Evolution Based Approach to Estimate the Shape and Size of Complex Shaped Anomalies Using EIT Measurements

NASA Astrophysics Data System (ADS)

Rashid, Ahmar; Khambampati, Anil Kumar; Kim, Bong Seok; Liu, Dong; Kim, Sin; Kim, Kyung Youn

EIT image reconstruction is an ill-posed problem, the spatial resolution of the estimated conductivity distribution is usually poor and the external voltage measurements are subject to variable noise. Therefore, EIT conductivity estimation cannot be used in the raw form to correctly estimate the shape and size of complex shaped regional anomalies. An efficient algorithm employing a shape based estimation scheme is needed. The performance of traditional inverse algorithms, such as the Newton Raphson method, used for this purpose is below par and depends upon the initial guess and the gradient of the cost functional. This paper presents the application of differential evolution (DE) algorithm to estimate complex shaped region boundaries, expressed as coefficients of truncated Fourier series, using EIT. DE is a simple yet powerful population-based, heuristic algorithm with the desired features to solve global optimization problems under realistic conditions. The performance of the algorithm has been tested through numerical simulations, comparing its results with that of the traditional modified Newton Raphson (mNR) method.

Adaptive Hybrid Picture Coding. Volume 2.

DTIC Science & Technology

1985-02-01

ooo5 V.a Measurement Vector ..eho..............57 V.b Size Variable o .entroi* Vector .......... .- 59 V * c Shape Vector .Ř 0-60o oe 6 I V~d...the Program for the Adaptive Line of Sight Method .i.. 18.. o ... .... .... 1 B Details of the Feature Vector FormationProgram .. o ...oo..-....- .122 C ...shape recognition is analogous to recognition of curves in space. Therefore, well known concepts and theorems from differential geometry can be 34 . o

Measuring Spatial Accessibility of Health Care Providers – Introduction of a Variable Distance Decay Function within the Floating Catchment Area (FCA) Method

PubMed Central

Groneberg, David A.

2016-01-01

We integrated recent improvements within the floating catchment area (FCA) method family into an integrated ‘iFCA`method. Within this method we focused on the distance decay function and its parameter. So far only distance decay functions with constant parameters have been applied. Therefore, we developed a variable distance decay function to be used within the FCA method. We were able to replace the impedance coefficient β by readily available distribution parameter (i.e. median and standard deviation (SD)) within a logistic based distance decay function. Hence, the function is shaped individually for every single population location by the median and SD of all population-to-provider distances within a global catchment size. Theoretical application of the variable distance decay function showed conceptually sound results. Furthermore, the existence of effective variable catchment sizes defined by the asymptotic approach to zero of the distance decay function was revealed, satisfying the need for variable catchment sizes. The application of the iFCA method within an urban case study in Berlin (Germany) confirmed the theoretical fit of the suggested method. In summary, we introduced for the first time, a variable distance decay function within an integrated FCA method. This function accounts for individual travel behaviors determined by the distribution of providers. Additionally, the function inherits effective variable catchment sizes and therefore obviates the need for determining variable catchment sizes separately. PMID:27391649

A repeatable geometric morphometric approach to the analysis of hand entheseal three-dimensional form.

PubMed

Karakostis, Fotios Alexandros; Hotz, Gerhard; Scherf, Heike; Wahl, Joachim; Harvati, Katerina

2018-05-01

The purpose of this study was to put forth a precise landmark-based technique for reconstructing the three-dimensional shape of human entheseal surfaces, to investigate whether the shape of human entheses is related to their size. The effects of age-at-death and bone length on entheseal shapes were also assessed. The sample comprised high-definition three-dimensional models of three right hand entheseal surfaces, which correspond to 45 male adult individuals of known age. For each enthesis, a particular landmark configuration was introduced, whose precision was tested both within and between observers. The effect of three-dimensional size, age-at-death, and bone length on shape was investigated through shape regression. The method presented high intra-observer and inter-observer repeatability. All entheses showed significant allometry, with the area of opponens pollicis demonstrating the most substantial relationship. This was particularly due to variation related to its proximal elongated ridge. The effect of age-at-death and bone length on entheses was limited. The introduced methodology can set a reliable basis for further research on the factors affecting entheseal shape. Using both size and shape, variables can provide further information on entheseal variation and its biomechanical implications. The low entheseal variation by age verifies that specimens under 50 years of age are not substantially affected by age-related changes. The lack of correlation between entheseal shape and bone length or age implies that other factors may regulate entheseal surfaces. Future research should focus on multivariate shape patterns among entheses and their association with occupation. © 2018 Wiley Periodicals, Inc.

A scalable and deformable stylized model of the adult human eye for radiation dose assessment

NASA Astrophysics Data System (ADS)

El Basha, Daniel; Furuta, Takuya; Iyer, Siva S. R.; Bolch, Wesley E.

2018-05-01

With recent changes in the recommended annual limit on eye lens exposures to ionizing radiation, there is considerable interest in predictive computational dosimetry models of the human eye and its various ocular structures including the crystalline lens, ciliary body, cornea, retina, optic nerve, and central retinal artery. Computational eye models to date have been constructed as stylized models, high-resolution voxel models, and polygon mesh models. Their common feature, however, is that they are typically constructed of nominal size and of a roughly spherical shape associated with the emmetropic eye. In this study, we present a geometric eye model that is both scalable (allowing for changes in eye size) and deformable (allowing for changes in eye shape), and that is suitable for use in radiation transport studies of ocular exposures and radiation treatments of eye disease. The model allows continuous and variable changes in eye size (axial lengths from 20 to 26 mm) and eye shape (diopters from  ‑12 to  +6). As an explanatory example of its use, five models (emmetropic eyes of small, average, and large size, as well as average size eyes of  ‑12D and  +6D) were constructed and subjected to normally incident beams of monoenergetic electrons and photons, with resultant energy-dependent dose coefficients presented for both anterior and posterior eye structures. Electron dose coefficients were found to vary with changes to both eye size and shape for the posterior eye structures, while their values for the crystalline lens were found to be sensitive to changes in only eye size. No dependence upon eye size or eye shape was found for photon dose coefficients at energies below 2 MeV. Future applications of the model can include more extensive tabulations of dose coefficients to all ocular structures (not only the lens) as a function of eye size and shape, as well as the assessment of x-ray therapies for ocular disease for patients with non-emmetropic eyes.

Large drinks are no mistake: Glass size, but not shape, affects alcoholic beverage drink pours

PubMed Central

Kerr, William C.; Patterson, Deidre; Koenen, Mary Albert; Greenfield, Thomas K.

2009-01-01

Introduction and Aims Drink alcohol content has been shown to be variable and is an important determinant of alcohol intake. This study evaluates claims regarding the effects of glass size and glass shape on the amount of alcohol in on-premise drinks. Design and Methods Wine and spirits drinks were purchased and measured in 80 on-premise establishments in 10 Northern California Counties. Drink alcohol content was measured as the liquid volume of the drink multiplied by the percentage alcohol by volume of given brands or from analysis of mixed drink and wine samples. Results Larger glass size was associated with larger on-premise pours of straight shots and mixed drinks served in the relatively large pint glass and variable “other” glass type were found to contain more alcohol than drinks served in a short wide glass. No significant differences were found for other drink types. Drinks poured in short wide glasses were not found to contain more alcohol than drinks poured in tall thin glasses. Bars with mostly black patrons were found to serve spirits drinks with more alcohol than bars with other patron types. Discussion and Conclusions Glass shape does not affect actual drink pours in the US but glass size does in some cases. Drinkers should measure wine and spirits pours at home to achieve standard drink amounts and consumer education programs should foster awareness of the relatively high drink alcohol content of on-premise wine and mixed spirits drinks. More research is needed to evaluate potential differences in drink pours by patron race and ethnicity. PMID:19594789

“What Women Like”: Influence of Motion and Form on Esthetic Body Perception

PubMed Central

Cazzato, Valentina; Siega, Serena; Urgesi, Cosimo

2012-01-01

Several studies have shown the distinct contribution of motion and form to the esthetic evaluation of female bodies. Here, we investigated how variations of implied motion and body size interact in the esthetic evaluation of female and male bodies in a sample of young healthy women. Participants provided attractiveness, beauty, and liking ratings for the shape and posture of virtual renderings of human bodies with variable body size and implied motion. The esthetic judgments for both shape and posture of human models were influenced by body size and implied motion, with a preference for thinner and more dynamic stimuli. Implied motion, however, attenuated the impact of extreme body size on the esthetic evaluation of body postures, while body size variations did not affect the preference for more dynamic stimuli. Results show that body form and action cues interact in esthetic perception, but the final esthetic appreciation of human bodies is predicted by a mixture of perceptual and affective evaluative components. PMID:22866044

Shell shape variation of queen conch Strombus gigas (Mesograstropoda: Strombidae) from Southwest Caribbean.

PubMed

Márquez, Edna Judith; Restrepo-Escobar, Natalia; Montoya-Herrera, Francisco Luis

2016-12-01

The endangered species Strombus gigas is a marine gastropod of significant economic importance through the Greater Caribbean region. In contrast to phenotypic plasticity, the role of genetics on shell variations in S. gigas has not been addressed so far, despite its importance in evolution, management and conservation of this species. This work used geometric morphometrics to investigate the phenotypic variation of 219 shells of S. gigas from eight sites of the Colombian Southwest Caribbean. Differences in mean size between sexes and among sites were contrasted by analysis of variance. Allometry was tested by multivariate regression and the hypothesis of common slope was contrasted by covariance multivariate analysis. Differences in the shell shape among sites were analyzed by principal component analysis. Sexual size dimorphism was not significant, whereas sexual shape dimorphism was significant and variable across sites. Differences in the shell shape among sites were concordant with genetic differences based on microsatellite data, supporting its genetic background. Besides, differences in the shell shape between populations genetically similar suggest a role of phenotypic plasticity in the morphometric variation of the shell shape. These outcomes evidence the role of genetic background and phenotypic plasticity in the shell shape of S. gigas. Thus, geometric morphometrics of shell shape may constitute a complementary tool to explore the genetic diversity of this species.

Magnetization Reversal of Nanoscale Islands: How Size and Shape Affect the Arrhenius Prefactor

NASA Astrophysics Data System (ADS)

Krause, S.; Herzog, G.; Stapelfeldt, T.; Berbil-Bautista, L.; Bode, M.; Vedmedenko, E. Y.; Wiesendanger, R.

2009-09-01

The thermal switching behavior of individual in-plane magnetized Fe/W(110) nanoislands is investigated by a combined study of variable-temperature spin-polarized scanning tunneling microscopy and Monte Carlo simulations. Even for islands consisting of less than 100 atoms the magnetization reversal takes place via nucleation and propagation. The Arrhenius prefactor is found to strongly depend on the individual island size and shape, and based on the experimental results a simple model is developed to describe the magnetization reversal in terms of metastable states. Complementary Monte Carlo simulations confirm the model and provide new insight into the microscopic processes involved in magnetization reversal of smallest nanomagnets.

The 'temporal effect' in hominids: Reinvestigating the nature of support for a chimp-human clade in bone morphology.

PubMed

Pearson, Alannah; Groves, Colin; Cardini, Andrea

2015-11-01

In 2004, an analysis by Lockwood and colleagues of hard-tissue morphology, using geometric morphometrics on the temporal bone, succeeded in recovering the correct phylogeny of living hominids without resorting to potentially problematic methods for transforming continuous shape variables into meristic characters. That work has increased hope that by using modern analytical methods and phylogenetically informative anatomical data we might one day be able to accurately infer the relationships of hominins, including the closest extinct relatives of modern humans. In the present study, using 3D virtually generated models of the hominid temporal bone and a larger suite of geometric morphometric and comparative techniques, we have re-examined the evidence for a Pan-Homo clade. Despite differences in samples, as well as the type of raw data, the effect of measurement error (and especially landmark digitization by a different operator), but also a broader perspective brought in by our diverse set of approaches, our reanalysis largely supports Lockwood and colleagues' original results. However, by focusing not only mainly on shape (as in the original 2004 analysis) but also on size and 'size-corrected' (non-allometric) shape, we demonstrate that the strong phylogenetic signal in the temporal bone is largely related to similarities in size. Thus, with this study, we are not suggesting the use of a single 'character', such as size, for phylogenetic inference, but we do challenge the common view that shape, with its highly complex and multivariate nature, is necessarily more phylogenetically informative than size and that actually size and size-related shape variation (i.e., allometry) confound phylogenetic inference based on morphology. This perspective may in fact be less generalizable than often believed. Thus, while we confirm the original findings by Lockwood et al., we provide a deep reinterpretation of their nature and potential implications for hominid phylogenetics and we show how crucial it is not to overlook size in geometric morphometric analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evolutionary patterns and processes in the radiation of phyllostomid bats

PubMed Central

2011-01-01

Background The phyllostomid bats present the most extensive ecological and phenotypic radiation known among mammal families. This group is an important model system for studies of cranial ecomorphology and functional optimisation because of the constraints imposed by the requirements of flight. A number of studies supporting phyllostomid adaptation have focused on qualitative descriptions or correlating functional variables and diet, but explicit tests of possible evolutionary mechanisms and scenarios for phenotypic diversification have not been performed. We used a combination of morphometric and comparative methods to test hypotheses regarding the evolutionary processes behind the diversification of phenotype (mandible shape and size) and diet during the phyllostomid radiation. Results The different phyllostomid lineages radiate in mandible shape space, with each feeding specialisation evolving towards different axes. Size and shape evolve quite independently, as the main directions of shape variation are associated with mandible elongation (nectarivores) or the relative size of tooth rows and mandibular processes (sanguivores and frugivores), which are not associated with size changes in the mandible. The early period of phyllostomid diversification is marked by a burst of shape, size, and diet disparity (before 20 Mya), larger than expected by neutral evolution models, settling later to a period of relative phenotypic and ecological stasis. The best fitting evolutionary model for both mandible shape and size divergence was an Ornstein-Uhlenbeck process with five adaptive peaks (insectivory, carnivory, sanguivory, nectarivory and frugivory). Conclusions The radiation of phyllostomid bats presented adaptive and non-adaptive components nested together through the time frame of the family's evolution. The first 10 My of the radiation were marked by strong phenotypic and ecological divergence among ancestors of modern lineages, whereas the remaining 20 My were marked by stasis around a number of probable adaptive peaks. A considerable amount of cladogenesis and speciation in this period is likely to be the result of non-adaptive allopatric divergence or adaptations to peaks within major dietary categories. PMID:21605452

Evolutionary patterns and processes in the radiation of phyllostomid bats.

PubMed

Monteiro, Leandro R; Nogueira, Marcelo R

2011-05-23

The phyllostomid bats present the most extensive ecological and phenotypic radiation known among mammal families. This group is an important model system for studies of cranial ecomorphology and functional optimisation because of the constraints imposed by the requirements of flight. A number of studies supporting phyllostomid adaptation have focused on qualitative descriptions or correlating functional variables and diet, but explicit tests of possible evolutionary mechanisms and scenarios for phenotypic diversification have not been performed. We used a combination of morphometric and comparative methods to test hypotheses regarding the evolutionary processes behind the diversification of phenotype (mandible shape and size) and diet during the phyllostomid radiation. The different phyllostomid lineages radiate in mandible shape space, with each feeding specialisation evolving towards different axes. Size and shape evolve quite independently, as the main directions of shape variation are associated with mandible elongation (nectarivores) or the relative size of tooth rows and mandibular processes (sanguivores and frugivores), which are not associated with size changes in the mandible. The early period of phyllostomid diversification is marked by a burst of shape, size, and diet disparity (before 20 Mya), larger than expected by neutral evolution models, settling later to a period of relative phenotypic and ecological stasis. The best fitting evolutionary model for both mandible shape and size divergence was an Ornstein-Uhlenbeck process with five adaptive peaks (insectivory, carnivory, sanguivory, nectarivory and frugivory). The radiation of phyllostomid bats presented adaptive and non-adaptive components nested together through the time frame of the family's evolution. The first 10 My of the radiation were marked by strong phenotypic and ecological divergence among ancestors of modern lineages, whereas the remaining 20 My were marked by stasis around a number of probable adaptive peaks. A considerable amount of cladogenesis and speciation in this period is likely to be the result of non-adaptive allopatric divergence or adaptations to peaks within major dietary categories.

Indian Craniometric Variability and Affinities

PubMed Central

Raghavan, Pathmanathan; Bulbeck, David; Pathmanathan, Gayathiri; Rathee, Suresh Kanta

2013-01-01

Recently published craniometric and genetic studies indicate a predominantly indigenous ancestry of Indian populations. We address this issue with a fuller coverage of Indian craniometrics than any done before. We analyse metrical variability within Indian series, Indians' sexual dimorphism, differences between northern and southern Indians, index-based differences of Indian males from other series, and Indians' multivariate affinities. The relationship between a variable's magnitude and its variability is log-linear. This relationship is strengthened by excluding cranial fractions and series with a sample size less than 30. Male crania are typically larger than female crania, but there are also shape differences. Northern Indians differ from southern Indians in various features including narrower orbits and less pronounced medial protrusion of the orbits. Indians resemble Veddas in having small crania and similar cranial shape. Indians' wider geographic affinities lie with “Caucasoid” populations to the northwest, particularly affecting northern Indians. The latter finding is confirmed from shape-based Mahalanobis-D distances calculated for the best sampled male and female series. Demonstration of a distinctive South Asian craniometric profile and the intermediate status of northern Indians between southern Indians and populations northwest of India confirm the predominantly indigenous ancestry of northern and especially southern Indians. PMID:24455409

Wing geometry of Culex coronator (Diptera: Culicidae) from South and Southeast Brazil

PubMed Central

2014-01-01

Background The Coronator Group encompasses Culex coronator Dyar & Knab, Culex camposi Dyar, Culex covagarciai Forattini, Culex ousqua Dyar, Culex usquatissimus Dyar, Culex usquatus Dyar and Culex yojoae Strickman. Culex coronator has the largest geographic distribution, occurring in North, Central and South America. Moreover, it is a potential vector-borne mosquito species because females have been found naturally infected with several arboviruses, i.e., Saint Louis Encephalitis Virus, Venezuelan Equine Encephalitis Virus and West Nile Virus. Considering the epidemiological importance of Cx. coronator, we investigated the wing shape diversity of Cx. coronator from South and Southeast Brazil, a method to preliminarily estimate population diversity. Methods Field-collected immature stages of seven populations from a large geographical area in Brazil were maintained in the laboratory to obtain both females and males linked with pupal and/or larval exuviae. For each individual female, 18 landmarks of left wings were marked and digitalized. After Procrustes superimposition, discriminant analysis of shape was employed to quantify wing shape variation among populations. The isometric estimator centroid size was calculated to assess the overall wing size and allometry. Results Wing shape was polymorphic among populations of Cx. coronator. However, dissimilarities among populations were higher than those observed within each population, suggesting populational differentiation in Cx. coronator. Morphological distances between populations were not correlated to geographical distances, indicating that other factors may act on wing shape and thus, determining microevolutionary patterns in Cx. coronator. Despite the population differentiation, intrapopulational wing shape variability was equivalent among all seven populations. Conclusion The wing variability found in Cx. coronator populations brings to light a new biological problem to be investigated: the population genetics of Cx. coronator. Because of differences in the male genitalia, we also transferred Cx. yojoae to the Apicinus Subgroup. PMID:24721508

Can high resolution 3D topographic surveys provide reliable grain size estimates in gravel bed rivers?

NASA Astrophysics Data System (ADS)

Pearson, E.; Smith, M. W.; Klaar, M. J.; Brown, L. E.

2017-09-01

High resolution topographic surveys such as those provided by Structure-from-Motion (SfM) contain a wealth of information that is not always exploited in the generation of Digital Elevation Models (DEMs). In particular, several authors have related sub-metre scale topographic variability (or 'surface roughness') to sediment grain size by deriving empirical relationships between the two. In fluvial applications, such relationships permit rapid analysis of the spatial distribution of grain size over entire river reaches, providing improved data to drive three-dimensional hydraulic models, allowing rapid geomorphic monitoring of sub-reach river restoration projects, and enabling more robust characterisation of riverbed habitats. However, comparison of previously published roughness-grain-size relationships shows substantial variability between field sites. Using a combination of over 300 laboratory and field-based SfM surveys, we demonstrate the influence of inherent survey error, irregularity of natural gravels, particle shape, grain packing structure, sorting, and form roughness on roughness-grain-size relationships. Roughness analysis from SfM datasets can accurately predict the diameter of smooth hemispheres, though natural, irregular gravels result in a higher roughness value for a given diameter and different grain shapes yield different relationships. A suite of empirical relationships is presented as a decision tree which improves predictions of grain size. By accounting for differences in patch facies, large improvements in D50 prediction are possible. SfM is capable of providing accurate grain size estimates, although further refinement is needed for poorly sorted gravel patches, for which c-axis percentiles are better predicted than b-axis percentiles.

Coupling of Waves, Turbulence and Thermodynamics Across the Marginal Ice Zone

DTIC Science & Technology

2013-09-30

ice . The albedo of sea ice is large compared to open water, and most of the incoming solar radiation...ocean and the ice pack where the seasonal retreat of the main ice pack takes place. It is a highly variable sea ice environment, usually comprised of...many individual floes of variable shape and size and made of mixed ice types, from young forming ice to fragmented multiyear ice . The presence of sea

Identification and detection of simple 3D objects with severely blurred vision.

PubMed

Kallie, Christopher S; Legge, Gordon E; Yu, Deyue

2012-12-05

Detecting and recognizing three-dimensional (3D) objects is an important component of the visual accessibility of public spaces for people with impaired vision. The present study investigated the impact of environmental factors and object properties on the recognition of objects by subjects who viewed physical objects with severely reduced acuity. The experiment was conducted in an indoor testing space. We examined detection and identification of simple convex objects by normally sighted subjects wearing diffusing goggles that reduced effective acuity to 20/900. We used psychophysical methods to examine the effect on performance of important environmental variables: viewing distance (from 10-24 feet, or 3.05-7.32 m) and illumination (overhead fluorescent and artificial window), and object variables: shape (boxes and cylinders), size (heights from 2-6 feet, or 0.61-1.83 m), and color (gray and white). Object identification was significantly affected by distance, color, height, and shape, as well as interactions between illumination, color, and shape. A stepwise regression analysis showed that 64% of the variability in identification could be explained by object contrast values (58%) and object visual angle (6%). When acuity is severely limited, illumination, distance, color, height, and shape influence the identification and detection of simple 3D objects. These effects can be explained in large part by the impact of these variables on object contrast and visual angle. Basic design principles for improving object visibility are discussed.

Relationship of cranial robusticity to cranial form, geography and climate in Homo sapiens.

PubMed

Baab, Karen L; Freidline, Sarah E; Wang, Steven L; Hanson, Timothy

2010-01-01

Variation in cranial robusticity among modern human populations is widely acknowledged but not well-understood. While the use of "robust" cranial traits in hominin systematics and phylogeny suggests that these characters are strongly heritable, this hypothesis has not been tested. Alternatively, cranial robusticity may be a response to differences in diet/mastication or it may be an adaptation to cold, harsh environments. This study quantifies the distribution of cranial robusticity in 14 geographically widespread human populations, and correlates this variation with climatic variables, neutral genetic distances, cranial size, and cranial shape. With the exception of the occipital torus region, all traits were positively correlated with each other, suggesting that they should not be treated as individual characters. While males are more robust than females within each of the populations, among the independent variables (cranial shape, size, climate, and neutral genetic distances), only shape is significantly correlated with inter-population differences in robusticity. Two-block partial least-squares analysis was used to explore the relationship between cranial shape (captured by three-dimensional landmark data) and robusticity across individuals. Weak support was found for the hypothesis that robusticity was related to mastication as the shape associated with greater robusticity was similar to that described for groups that ate harder-to-process diets. Specifically, crania with more prognathic faces, expanded glabellar and occipital regions, and (slightly) longer skulls were more robust than those with rounder vaults and more orthognathic faces. However, groups with more mechanically demanding diets (hunter-gatherers) were not always more robust than groups practicing some form of agriculture.

Hematoma Shape, Hematoma Size, Glasgow Coma Scale Score and ICH Score: Which Predicts the 30-Day Mortality Better for Intracerebral Hematoma?

PubMed Central

Wang, Chih-Wei; Liu, Yi-Jui; Lee, Yi-Hsiung; Hueng, Dueng-Yuan; Fan, Hueng-Chuen; Yang, Fu-Chi; Hsueh, Chun-Jen; Kao, Hung-Wen; Juan, Chun-Jung; Hsu, Hsian-He

2014-01-01

Purpose To investigate the performance of hematoma shape, hematoma size, Glasgow coma scale (GCS) score, and intracerebral hematoma (ICH) score in predicting the 30-day mortality for ICH patients. To examine the influence of the estimation error of hematoma size on the prediction of 30-day mortality. Materials and Methods This retrospective study, approved by a local institutional review board with written informed consent waived, recruited 106 patients diagnosed as ICH by non-enhanced computed tomography study. The hemorrhagic shape, hematoma size measured by computer-assisted volumetric analysis (CAVA) and estimated by ABC/2 formula, ICH score and GCS score was examined. The predicting performance of 30-day mortality of the aforementioned variables was evaluated. Statistical analysis was performed using Kolmogorov-Smirnov tests, paired t test, nonparametric test, linear regression analysis, and binary logistic regression. The receiver operating characteristics curves were plotted and areas under curve (AUC) were calculated for 30-day mortality. A P value less than 0.05 was considered as statistically significant. Results The overall 30-day mortality rate was 15.1% of ICH patients. The hematoma shape, hematoma size, ICH score, and GCS score all significantly predict the 30-day mortality for ICH patients, with an AUC of 0.692 (P = 0.0018), 0.715 (P = 0.0008) (by ABC/2) to 0.738 (P = 0.0002) (by CAVA), 0.877 (P<0.0001) (by ABC/2) to 0.882 (P<0.0001) (by CAVA), and 0.912 (P<0.0001), respectively. Conclusion Our study shows that hematoma shape, hematoma size, ICH scores and GCS score all significantly predict the 30-day mortality in an increasing order of AUC. The effect of overestimation of hematoma size by ABC/2 formula in predicting the 30-day mortality could be remedied by using ICH score. PMID:25029592

Preparation of narrow dispersity gold nanorods by asymmetrical flow field-flow fractionation and investigation of surface plasmon resonance.

PubMed

Runyon, J Ray; Goering, Adam; Yong, Ken-Tye; Williams, S Kim Ratanathanawongs

2013-01-15

The development of an asymmetrical field-flow fractionation (AsFlFFF) method for separating gold nanorods (GNR) is reported. Collected fractions containing GNR subpopulations with aspect ratios, sizes, and shapes which are more narrowly dispersed than the original population were further characterized by UV-vis spectroscopy and transmission electron microscopy. This ability to obtain different sizes and shapes of nanoparticles enabled the evaluation of a new approach to estimating the retention time and hydrodynamic size of nanorods and the investigation of GNR optical properties at a previously unattainable level of detail. Experimental results demonstrate that the longitudinal surface plasmon absorption maximum of GNRs is correlated with the effective particle radius in addition to the aspect ratio. This may account for some of the variabilities reported in published empirical data from different research groups and supports reports of simulated absorption spectra of GNRs of different physical dimensions. The use of AsFlFFF with dual UV-vis detection to rapidly assess relative changes in GNR subpopulations was demonstrated for irregularly shaped gold nanoparticles formed at different synthesis temperatures.

Beyond the sniffer: frontal sinuses in Carnivora.

PubMed

Curtis, Abigail A; Van Valkenburgh, Blaire

2014-11-01

Paranasal sinuses are some of the most poorly understood features of mammalian cranial anatomy. They are highly variable in presence and form among species, but their function is not well understood. The best-supported explanations for the function of sinuses is that they opportunistically fill mechanically unnecessary space, but that in some cases, sinuses in combination with the configuration of the frontal bone may improve skull performance by increasing skull strength and dissipating stresses more evenly. We used CT technology to investigate patterns in frontal sinus size and shape disparity among three families of carnivores: Canidae, Felidae, and Hyaenidae. We provide some of the first quantitative data on sinus morphology for these three families, and employ a novel method to quantify the relationship between three-dimensional sinus shape and skull shape. As expected, frontal sinus size and shape were more strongly correlated with frontal bone size and shape than with the morphology of the skull as a whole. However, sinus morphology was also related to allometric differences among families that are linked to biomechanical function. Our results support the hypothesis that frontal sinuses most often opportunistically fill space that is mechanically unnecessary, and they can facilitate cranial shape changes that reduce stress during feeding. Moreover, we suggest that the ability to form frontal sinuses allows species to modify skull function without compromising the performance of more functionally constrained regions such as the nasal chamber (heat/water conservation, olfaction), and braincase (housing the brain and sensory structures). © 2014 Wiley Periodicals, Inc.

Neighbouring populations, opposite dynamics: influence of body size and environmental variation on the demography of stream-resident brown trout (Salmo trutta).

PubMed

Fernández-Chacón, Albert; Genovart, Meritxell; Álvarez, David; Cano, José M; Ojanguren, Alfredo F; Rodriguez-Muñoz, Rolando; Nicieza, Alfredo G

2015-06-01

In organisms such as fish, where body size is considered an important state variable for the study of their population dynamics, size-specific growth and survival rates can be influenced by local variation in both biotic and abiotic factors, but few studies have evaluated the complex relationships between environmental variability and size-dependent processes. We analysed a 6-year capture-recapture dataset of brown trout (Salmo trutta) collected at 3 neighbouring but heterogeneous mountain streams in northern Spain with the aim of investigating the factors shaping the dynamics of local populations. The influence of body size and water temperature on survival and individual growth was assessed under a multi-state modelling framework, an extension of classical capture-recapture models that considers the state (i.e. body size) of the individual in each capture occasion and allows us to obtain state-specific demographic rates and link them to continuous environmental variables. Individual survival and growth patterns varied over space and time, and evidence of size-dependent survival was found in all but the smallest stream. At this stream, the probability of reaching larger sizes was lower compared to the other wider and deeper streams. Water temperature variables performed better in the modelling of the highest-altitude population, explaining over a 99 % of the variability in maturation transitions and survival of large fish. The relationships between body size, temperature and fitness components found in this study highlight the utility of multi-state approaches to investigate small-scale demographic processes in heterogeneous environments, and to provide reliable ecological knowledge for management purposes.

Development of laser-guided precision sprayers for tree crop applications

USDA-ARS?s Scientific Manuscript database

Tree crops in nurseries and orchards have great variations in shapes, sizes, canopy densities and gaps between in-row trees. The variability requires future sprayers to be flexible to spray the amount of chemicals that can match tree structures. A precision air-assisted sprayer was developed to appl...

40 CFR 799.9620 - TSCA neurotoxicity screening battery.

Code of Federal Regulations, 2011 CFR

2011-07-01

... address in paragraph (g) of this section. (c) Definitions. The following definitions apply to this section... facilitate interpretation of the data. (C) Additional measures. Other measures may also be included and the.... Among the variables which can affect motor activity are sound level, size and shape of the test cage...

40 CFR 799.9620 - TSCA neurotoxicity screening battery.

Code of Federal Regulations, 2010 CFR

2010-07-01

... address in paragraph (g) of this section. (c) Definitions. The following definitions apply to this section... facilitate interpretation of the data. (C) Additional measures. Other measures may also be included and the.... Among the variables which can affect motor activity are sound level, size and shape of the test cage...

Development of a laser-guided embedded-computer-controlled air-assisted precision sprayer

USDA-ARS?s Scientific Manuscript database

An embedded computer-controlled, laser-guided, air-assisted, variable-rate precision sprayer was developed to automatically adjust spray outputs on both sides of the sprayer to match presence, size, shape, and foliage density of tree crops. The sprayer was the integration of an embedded computer, a ...

Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample.

PubMed

Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K

2016-06-01

The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population. Copyright © 2016. Published by Elsevier GmbH.

Shape Analysis of 3D Head Scan Data for U.S. Respirator Users

NASA Astrophysics Data System (ADS)

Zhuang, Ziqing; Slice, DennisE; Benson, Stacey; Lynch, Stephanie; Viscusi, DennisJ

2010-12-01

In 2003, the National Institute for Occupational Safety and Health (NIOSH) conducted a head-and-face anthropometric survey of diverse, civilian respirator users. Of the 3,997 subjects measured using traditional anthropometric techniques, surface scans and 26 three-dimensional (3D) landmark locations were collected for 947 subjects. The objective of this study was to report the size and shape variation of the survey participants using the 3D data. Generalized Procrustes Analysis (GPA) was conducted to standardize configurations of landmarks associated with individuals into a common coordinate system. The superimposed coordinates for each individual were used as commensurate variables that describe individual shape and were analyzed using Principal Component Analysis (PCA) to identify population variation. The first four principal components (PC) account for 49% of the total sample variation. The first PC indicates that overall size is an important component of facial variability. The second PC accounts for long and narrow or short and wide faces. Longer narrow orbits versus shorter wider orbits can be described by PC3, and PC4 represents variation in the degree of ortho/prognathism. Geometric Morphometrics provides a detailed and interpretable assessment of morphological variation that may be useful in assessing respirators and devising new test and certification standards.

Variability in body size and shape of UK offshore workers: A cluster analysis approach.

PubMed

Stewart, Arthur; Ledingham, Robert; Williams, Hector

2017-01-01

Male UK offshore workers have enlarged dimensions compared with UK norms and knowledge of specific sizes and shapes typifying their physiques will assist a range of functions related to health and ergonomics. A representative sample of the UK offshore workforce (n = 588) underwent 3D photonic scanning, from which 19 extracted dimensional measures were used in k-means cluster analysis to characterise physique groups. Of the 11 resulting clusters four somatotype groups were expressed: one cluster was muscular and lean, four had greater muscularity than adiposity, three had equal adiposity and muscularity and three had greater adiposity than muscularity. Some clusters appeared constitutionally similar to others, differing only in absolute size. These cluster centroids represent an evidence-base for future designs in apparel and other applications where body size and proportions affect functional performance. They also constitute phenotypic evidence providing insight into the 'offshore culture' which may underpin the enlarged dimensions of offshore workers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vocal tract length and acoustics of vocalization in the domestic dog (Canis familiaris).

PubMed

Riede, T; Fitch, T

1999-10-01

The physical nature of the vocal tract results in the production of formants during vocalisation. In some animals (including humans), receivers can derive information (such as body size) about sender characteristics on the basis of formant characteristics. Domestication and selective breeding have resulted in a high variability in head size and shape in the dog (Canis familiaris), suggesting that there might be large differences in the vocal tract length, which could cause formant behaviour to affect interbreed communication. Lateral radiographs were made of dogs from several breeds ranging in size from a Yorkshire terrier (2.5 kg) to a German shepherd (50 kg) and were used to measure vocal tract length. In addition, we recorded an acoustic signal (growling) from some dogs. Significant correlations were found between vocal tract length, body mass and formant dispersion, suggesting that formant dispersion can deliver information about the body size of the vocalizer. Because of the low correlation between vocal tract length and the first formant, we predict a non-uniform vocal tract shape.

Locomotion of Amorphous Surface Robots

NASA Technical Reports Server (NTRS)

Bradley, Arthur T. (Inventor)

2018-01-01

An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

Locomotion of Amorphous Surface Robots

NASA Technical Reports Server (NTRS)

Bradley, Arthur T. (Inventor)

2016-01-01

An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

Locomotion of Amorphous Surface Robots

NASA Technical Reports Server (NTRS)

Bradley, Arthur T. (Inventor)

2014-01-01

An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

Spatiotemporal attention operator using isotropic contrast and regional homogeneity

NASA Astrophysics Data System (ADS)

Palenichka, Roman; Lakhssassi, Ahmed; Zaremba, Marek

2011-04-01

A multiscale operator for spatiotemporal isotropic attention is proposed to reliably extract attention points during image sequence analysis. Its consecutive local maxima indicate attention points as the centers of image fragments of variable size with high intensity contrast, region homogeneity, regional shape saliency, and temporal change presence. The scale-adaptive estimation of temporal change (motion) and its aggregation with the regional shape saliency contribute to the accurate determination of attention points in image sequences. Multilocation descriptors of an image sequence are extracted at the attention points in the form of a set of multidimensional descriptor vectors. A fast recursive implementation is also proposed to make the operator's computational complexity independent from the spatial scale size, which is the window size in the spatial averaging filter. Experiments on the accuracy of attention-point detection have proved the operator consistency and its high potential for multiscale feature extraction from image sequences.

Disentangling the phylogenetic and ecological components of spider phenotypic variation.

PubMed

Gonçalves-Souza, Thiago; Diniz-Filho, José Alexandre Felizola; Romero, Gustavo Quevedo

2014-01-01

An understanding of how the degree of phylogenetic relatedness influences the ecological similarity among species is crucial to inferring the mechanisms governing the assembly of communities. We evaluated the relative importance of spider phylogenetic relationships and ecological niche (plant morphological variables) to the variation in spider body size and shape by comparing spiders at different scales: (i) between bromeliads and dicot plants (i.e., habitat scale) and (ii) among bromeliads with distinct architectural features (i.e., microhabitat scale). We partitioned the interspecific variation in body size and shape into phylogenetic (that express trait values as expected by phylogenetic relationships among species) and ecological components (that express trait values independent of phylogenetic relationships). At the habitat scale, bromeliad spiders were larger and flatter than spiders associated with the surrounding dicots. At this scale, plant morphology sorted out close related spiders. Our results showed that spider flatness is phylogenetically clustered at the habitat scale, whereas it is phylogenetically overdispersed at the microhabitat scale, although phylogenic signal is present in both scales. Taken together, these results suggest that whereas at the habitat scale selective colonization affect spider body size and shape, at fine scales both selective colonization and adaptive evolution determine spider body shape. By partitioning the phylogenetic and ecological components of phenotypic variation, we were able to disentangle the evolutionary history of distinct spider traits and show that plant architecture plays a role in the evolution of spider body size and shape. We also discussed the relevance in considering multiple scales when studying phylogenetic community structure.

Disentangling the Phylogenetic and Ecological Components of Spider Phenotypic Variation

PubMed Central

Gonçalves-Souza, Thiago; Diniz-Filho, José Alexandre Felizola; Romero, Gustavo Quevedo

2014-01-01

An understanding of how the degree of phylogenetic relatedness influences the ecological similarity among species is crucial to inferring the mechanisms governing the assembly of communities. We evaluated the relative importance of spider phylogenetic relationships and ecological niche (plant morphological variables) to the variation in spider body size and shape by comparing spiders at different scales: (i) between bromeliads and dicot plants (i.e., habitat scale) and (ii) among bromeliads with distinct architectural features (i.e., microhabitat scale). We partitioned the interspecific variation in body size and shape into phylogenetic (that express trait values as expected by phylogenetic relationships among species) and ecological components (that express trait values independent of phylogenetic relationships). At the habitat scale, bromeliad spiders were larger and flatter than spiders associated with the surrounding dicots. At this scale, plant morphology sorted out close related spiders. Our results showed that spider flatness is phylogenetically clustered at the habitat scale, whereas it is phylogenetically overdispersed at the microhabitat scale, although phylogenic signal is present in both scales. Taken together, these results suggest that whereas at the habitat scale selective colonization affect spider body size and shape, at fine scales both selective colonization and adaptive evolution determine spider body shape. By partitioning the phylogenetic and ecological components of phenotypic variation, we were able to disentangle the evolutionary history of distinct spider traits and show that plant architecture plays a role in the evolution of spider body size and shape. We also discussed the relevance in considering multiple scales when studying phylogenetic community structure. PMID:24651264

Microbial community dynamics in soil aggregates shape biogeochemical gas fluxes from soil profiles - upscaling an aggregate biophysical model.

PubMed

Ebrahimi, Ali; Or, Dani

2016-09-01

Microbial communities inhabiting soil aggregates dynamically adjust their activity and composition in response to variations in hydration and other external conditions. These rapid dynamics shape signatures of biogeochemical activity and gas fluxes emitted from soil profiles. Recent mechanistic models of microbial processes in unsaturated aggregate-like pore networks revealed a highly dynamic interplay between oxic and anoxic microsites jointly shaped by hydration conditions and by aerobic and anaerobic microbial community abundance and self-organization. The spatial extent of anoxic niches (hotspots) flicker in time (hot moments) and support substantial anaerobic microbial activity even in aerated soil profiles. We employed an individual-based model for microbial community life in soil aggregate assemblies represented by 3D angular pore networks. Model aggregates of different sizes were subjected to variable water, carbon and oxygen contents that varied with soil depth as boundary conditions. The study integrates microbial activity within aggregates of different sizes and soil depth to obtain estimates of biogeochemical fluxes from the soil profile. The results quantify impacts of dynamic shifts in microbial community composition on CO2 and N2 O production rates in soil profiles in good agreement with experimental data. Aggregate size distribution and the shape of resource profiles in a soil determine how hydration dynamics shape denitrification and carbon utilization rates. Results from the mechanistic model for microbial activity in aggregates of different sizes were used to derive parameters for analytical representation of soil biogeochemical processes across large scales of practical interest for hydrological and climate models. © 2016 John Wiley & Sons Ltd.

Effects of process variables on the properties of YBa2Cu3O(7-x) ceramics formed by investment casting

NASA Technical Reports Server (NTRS)

Hooker, M. W.; Taylor, T. D.; Leigh, H. D.; Wise, S. A.; Buckley, J. D.; Vasquez, P.; Buck, G. M.; Hicks, L. P.

1993-01-01

An investment casting process has been developed to produce net-shape, superconducting ceramics. In this work, a factorial experiment was performed to determine the critical process parameters for producing cast YBa2Cu3O7 ceramics with optimum properties. An analysis of variance procedure indicated that the key variables in casting superconductive ceramics are the particle size distribution and sintering temperature. Additionally, the interactions between the sintering temperature and the other process parameters (e.g., particle size distribution and the use of silver dopants) were also found to influence the density, porosity, and critical current density of the fired ceramics.

Real-Time Variable Rate Spraying in Orchards and Vineyards: A Review

NASA Astrophysics Data System (ADS)

Wandkar, Sachin Vilas; Bhatt, Yogesh Chandra; Jain, H. K.; Nalawade, Sachin M.; Pawar, Shashikant G.

2018-06-01

Effective and efficient use of pesticides in the orchards is of concern since many years. With the conventional constant rate sprayers, equal dose of pesticide is applied to each tree. Since, there is great variation in size and shape of each tree in the orchard, trees gets either oversprayed or undersprayed. Real-time variable rate spraying technology offers pesticide application in accordance with tree size. With the help of suitable sensors, tree characteristics such as canopy volume, foliage density, etc. can be acquired and with the micro-processing unit coupled with proper algorithm, flow of electronic proportional valves can be controlled thus, controlling the flow rate of nozzles according to tree characteristics. Also, sensors can help in the detection of spaces in-between trees which allows to control the spray in spaces. Variable rate spraying helps in achieving precision in spraying operation especially inside orchards. This paper reviews the real-time variable rate spraying technology and efforts made by the various researchers for real-time variable application in the orchards and vineyards.

The Tölz Temporal Topography Study: mapping the visual field across the life span. Part II: cognitive factors shaping visual field maps.

PubMed

Poggel, Dorothe A; Treutwein, Bernhard; Calmanti, Claudia; Strasburger, Hans

2012-08-01

Part I described the topography of visual performance over the life span. Performance decline was explained only partly by deterioration of the optical apparatus. Part II therefore examines the influence of higher visual and cognitive functions. Visual field maps for 95 healthy observers of static perimetry, double-pulse resolution (DPR), reaction times, and contrast thresholds, were correlated with measures of visual attention (alertness, divided attention, spatial cueing), visual search, and the size of the attention focus. Correlations with the attentional variables were substantial, particularly for variables of temporal processing. DPR thresholds depended on the size of the attention focus. The extraction of cognitive variables from the correlations between topographical variables and participant age substantially reduced those correlations. There is a systematic top-down influence on the aging of visual functions, particularly of temporal variables, that largely explains performance decline and the change of the topography over the life span.

Real-Time Variable Rate Spraying in Orchards and Vineyards: A Review

NASA Astrophysics Data System (ADS)

Wandkar, Sachin Vilas; Bhatt, Yogesh Chandra; Jain, H. K.; Nalawade, Sachin M.; Pawar, Shashikant G.

2018-02-01

Effective and efficient use of pesticides in the orchards is of concern since many years. With the conventional constant rate sprayers, equal dose of pesticide is applied to each tree. Since, there is great variation in size and shape of each tree in the orchard, trees gets either oversprayed or undersprayed. Real-time variable rate spraying technology offers pesticide application in accordance with tree size. With the help of suitable sensors, tree characteristics such as canopy volume, foliage density, etc. can be acquired and with the micro-processing unit coupled with proper algorithm, flow of electronic proportional valves can be controlled thus, controlling the flow rate of nozzles according to tree characteristics. Also, sensors can help in the detection of spaces in-between trees which allows to control the spray in spaces. Variable rate spraying helps in achieving precision in spraying operation especially inside orchards. This paper reviews the real-time variable rate spraying technology and efforts made by the various researchers for real-time variable application in the orchards and vineyards.

Plasticity as Phenotype: G x E Interaction in a Freshwater Snail

NASA Astrophysics Data System (ADS)

Brunkow, P. E.; Calloway, S. A.

2005-05-01

Plasticity in morphological development allows species to accommodate environmental variation experienced during growth; however, genetic variation for phenotypic plasticity per se has been relatively under-studied. We utilized the well-documented plastic response of shell development to predator cues in a freshwater snail to quantify genetic variation for plasticity in growth rate and shell shape. Field-caught pairs of snails reproduced in the laboratory to create families of full siblings, which were then divided and allowed to grow in control and predator cue treatments. Predator (crayfish) cues had significant effects on both size-corrected growth rate and shell shape; family identity also significantly affected both final shell shape and growth rate. The interaction between predator treatment and family identity significantly affected snail growth rate but not final shell shape, suggesting genetic variation in the plastic response to predator cues for a physiological variable (growth rate) but not for a variable known to mechanically reduce the risk of predation (shell shape), at least in this population of snails. The possibility that risk of multiple modes of predation (i.e., both fish and crayfish) in some populations might maintain genetic variation in morphological plasticity is discussed.

Human mandibular shape is associated with masticatory muscle force.

PubMed

Sella-Tunis, Tanya; Pokhojaev, Ariel; Sarig, Rachel; O'Higgins, Paul; May, Hila

2018-04-16

Understanding how and to what extent forces applied to the mandible by the masticatory muscles influence its form, is of considerable importance from clinical, anthropological and evolutionary perspectives. This study investigates these questions. Head CT scans of 382 adults were utilized to measure masseter and temporalis muscle cross-sectional areas (CSA) as a surrogate for muscle force, and 17 mandibular anthropometric measurements. Sixty-two mandibles of young individuals (20-40 years) whose scans were without artefacts (e.g., due to tooth filling) were segmented and landmarked for geometric morphometric analysis. The association between shape and muscle CSA (controlled for size) was assessed using two-block partial least squares analysis. Correlations were computed between mandibular variables and muscle CSAs (all controlled for size). A significant association was found between mandibular shape and muscle CSAs, i.e. larger CSAs are associated with a wider more trapezoidal ramus, more massive coronoid, more rectangular body and a more curved basal arch. Linear measurements yielded low correlations with muscle CSAs. In conclusion, this study demonstrates an association between mandibular muscle force and mandibular shape, which is not as readily identified from linear measurements. Retrodiction of masticatory muscle force and so of mandibular loading is therefore best based on overall mandibular shape.

Foveal shape and structure in a normal population.

PubMed

Tick, Sarah; Rossant, Florence; Ghorbel, Itebeddine; Gaudric, Alain; Sahel, José-Alain; Chaumet-Riffaud, Philippe; Paques, Michel

2011-07-29

The shape of the human fovea presents important but still poorly characterized variations. In this study, the variability of the shape and structure of normal foveae were examined. In a group of 110 eyes of 57 healthy adults, the shape and structure of the fovea were analyzed by automated segmentation of retinal layer on high-resolution optical coherence tomography scans. In an additional group of 10 normal eyes of 10 patients undergoing fluorescein angiography, the size of the foveal avascular zone (FAZ) was correlated to foveal shape. From the thickest to the thinnest fovea, there was a structural continuum ranging from a shallow pit with continuity of the inner nuclear layer (INL) over the center (seven eyes; 6.7%), to a complete separation of inner layers overlying a flat and thinner central outer nuclear layer (ONL; eight eyes; 7.3%). Central foveal thickness correlated inversely to the degree of inner layer separation and to the surface of the FAZ. Foveal structure strongly correlates with its neurovascular organization. The findings support a developmental model in which the size of the FAZ determines the extent of centrifugal migration of inner retinal layers, which counteracts in some way the centripetal packing of cone photoreceptors.

The zebrafish world of colors and shapes: preference and discrimination.

PubMed

Oliveira, Jessica; Silveira, Mayara; Chacon, Diana; Luchiari, Ana

2015-04-01

Natural environment imposes many challenges to animals, which have to use cognitive abilities to cope with and exploit it to enhance their fitness. Since zebrafish is a well-established model for cognitive studies and high-throughput screening for drugs and diseases that affect cognition, we tested their ability for ambient color preference and 3D objects discrimination to establish a protocol for memory evaluation. For the color preference test, zebrafish were observed in a multiple-chamber tank with different environmental color options. Zebrafish showed preference for blue and green, and avoided yellow and red. For the 3D objects discrimination, zebrafish were allowed to explore two equal objects and then observed in a one-trial test in which a new color, size, or shape of the object was presented. Zebrafish showed discrimination for color, shape, and color+shape combined, but not size. These results imply that zebrafish seem to use some categorical system to discriminate items, and distracters affect their ability for discrimination. The type of variables available (color and shape) may favor zebrafish objects perception and facilitate discrimination processing. We suggest that this easy and simple memory test could serve as a useful screening tool for cognitive dysfunction and neurotoxicological studies.

Pancreas and cyst segmentation

NASA Astrophysics Data System (ADS)

Dmitriev, Konstantin; Gutenko, Ievgeniia; Nadeem, Saad; Kaufman, Arie

2016-03-01

Accurate segmentation of abdominal organs from medical images is an essential part of surgical planning and computer-aided disease diagnosis. Many existing algorithms are specialized for the segmentation of healthy organs. Cystic pancreas segmentation is especially challenging due to its low contrast boundaries, variability in shape, location and the stage of the pancreatic cancer. We present a semi-automatic segmentation algorithm for pancreata with cysts. In contrast to existing automatic segmentation approaches for healthy pancreas segmentation which are amenable to atlas/statistical shape approaches, a pancreas with cysts can have even higher variability with respect to the shape of the pancreas due to the size and shape of the cyst(s). Hence, fine results are better attained with semi-automatic steerable approaches. We use a novel combination of random walker and region growing approaches to delineate the boundaries of the pancreas and cysts with respective best Dice coefficients of 85.1% and 86.7%, and respective best volumetric overlap errors of 26.0% and 23.5%. Results show that the proposed algorithm for pancreas and pancreatic cyst segmentation is accurate and stable.

Effects of environmental disturbance on phenotypic variation: an integrated assessment of canalization, developmental stability, modularity, and allometry in lizard head shape.

PubMed

Lazić, Marko M; Carretero, Miguel A; Crnobrnja-Isailović, Jelka; Kaliontzopoulou, Antigoni

2015-01-01

When populations experience suboptimal conditions, the mechanisms involved in the regulation of phenotypic variation can be challenged, resulting in increased phenotypic variance. This kind of disturbance can be diagnosed by using morphometric tools to study morphological patterns at different hierarchical levels and evaluate canalization, developmental stability, integration, modularity, and allometry. We assess the effect of urbanization on phenotypic variation in the common wall lizard (Podarcis muralis) by using geometric morphometrics to assess disturbance to head shape development. The head shapes of urban lizards were more variable and less symmetric, suggesting that urban living is more likely to disturb development. Head shape variation was congruent within and across individuals, which indicated that canalization and developmental stability are two related phenomena in these organisms. Furthermore, urban lizards exhibited smaller mean head sizes, divergent size-shape allometries, and increased deviation from within-group allometric lines. This suggests that mechanisms regulating head shape allometry may also be disrupted. The integrated evaluation of several measures of developmental instability at different hierarchical levels, which provided in this case congruent results, can be a powerful methodological guide for future studies, as it enhances the detection of environmental disturbances on phenotypic variation and aids biological interpretation of the results.

Stony Endocarp Dimension and Shape Variation in Prunus Section Prunus

PubMed Central

Depypere, Leander; Chaerle, Peter; Mijnsbrugge, Kristine Vander; Goetghebeur, Paul

2007-01-01

Background and Aims Identification of Prunus groups at subspecies or variety level is complicated by the wide range of variation and morphological transitional states. Knowledge of the degree of variability within and between species is a sine qua non for taxonomists. Here, a detailed study of endocarp dimension and shape variation for taxa of Prunus section Prunus is presented. Method The sample size necessary to obtain an estimation of the population mean with a precision of 5 % was determined by iteration. Two cases were considered: (1) the population represents an individual; and (2) the population represents a species. The intra-individual and intraspecific variation of Prunus endocarps was studied by analysing the coefficients of variance for dimension and shape parameters. Morphological variation among taxa was assessed using univariate statistics. The influence of the time of sampling and the level of hydration on endocarp dimensions and shape was examined by means of pairwise t-tests. In total, 14 endocarp characters were examined for five Eurasian plum taxa. Key Results All linear measurements and index values showed a low or normal variability on the individual and species level. In contrast, the parameter ‘Vertical Asymmetry’ had high coefficients of variance for one or more of the taxa studied. Of all dimension and shape parameters studied, only ‘Triangle’ differed significantly between mature endocarps of P. insititia sampled with a time difference of 1 month. The level of hydration affected endocarp dimensions and shape significantly. Conclusions Index values and the parameters ‘Perimeter’, ‘Area’, ‘Triangle’, ‘Ellipse’, ‘Circular’ and ‘Rectangular’, based on sample sizes and coefficients of variance, were found to be most appropriate for further taxonomic analysis. However, use of one, single endocarp parameter is not satisfactory for discrimination between Eurasian plum taxa, mainly because of overlapping ranges. Before analysing dried endocarps, full hydration is recommended, as this restores the original dimensions and shape. PMID:17965026

Calculations of the variability of ice cloud radiative properties at selected solar wavelengths

NASA Technical Reports Server (NTRS)

Welch, R. M.; Zdunkowski, W. G.; Cox, S. K.

1980-01-01

This study shows that there is surprising little difference in values of reflectance, absorptance, and transmittance for many of the intermediate-size particle spectra. Particle size distributions with mode radii ranging from approximately 50 to 300 microns, irrespective of particle shape and nearly independent of the choice of size distribution representation, give relatively similar flux values. The very small particle sizes, however, have significantly larger values of reflectance and transmittance with corresponding smaller values of absorptance than do the larger particle sizes. The very large particle modes produce very small values of reflectance and transmittance along with very large values of absorptance. Such variations are particularly noticeable when plotted as a function of wavelength.

Hysteresis modeling of magnetic shape memory alloy actuator based on Krasnosel'skii-Pokrovskii model.

PubMed

Zhou, Miaolei; Wang, Shoubin; Gao, Wei

2013-01-01

As a new type of intelligent material, magnetically shape memory alloy (MSMA) has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP) model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator.

Hysteresis Modeling of Magnetic Shape Memory Alloy Actuator Based on Krasnosel'skii-Pokrovskii Model

PubMed Central

Wang, Shoubin; Gao, Wei

2013-01-01

As a new type of intelligent material, magnetically shape memory alloy (MSMA) has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP) model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator. PMID:23737730

Analysis of intraspecific seed diversity in Astragalus aquilanus (Fabaceae), an endemic species of Central Apennine.

PubMed

Di Cecco, V; Di Musciano, M; D'Archivio, A A; Frattaroli, A R; Di Martino, L

2018-05-20

This work aims to study seeds of the endemic species Astragalus aquilanus from four different populations of central Italy. We investigated seed morpho-colorimetric features (shape and size) and chemical differences (through infrared spectroscopy) among populations and between dark and light seeds. Seed morpho-colorimetric quantitative variables, describing shape, size and colour traits, were measured using image analysis techniques. Fourier transform infrared (FT-IR) spectroscopy was used to attempt seed chemical characterisation. The measured data were analysed by step-wise linear discriminant analysis (LDA). Moreover, we analysed the correlation between the four most important traits and six climatic variables extracted from WorldClim 2.0. The LDA on seeds traits shows clear differentiation of the four populations, which can be attributed to different chemical composition, as confirmed by Wilk's lambda test (P < 0.001). A strong correlation between morphometric traits and temperature (annual mean temperature, mean temperature of the warmest and coolest quarter), colorimetric traits and precipitation (annual precipitation, precipitation of wettest and driest quarter) was observed. The characterisation of A. aquilanus seeds shows large intraspecific plasticity both in morpho-colorimetric and chemical composition. These results confirm the strong relationship between the type of seed produced and the climatic variables. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Human cranial anatomy and the differential preservation of population history and climate signatures.

PubMed

Harvati, Katerina; Weaver, Timothy D

2006-12-01

Cranial morphology is widely used to reconstruct evolutionary relationships, but its reliability in reflecting phylogeny and population history has been questioned. Some cranial regions, particularly the face and neurocranium, are believed to be influenced by the environment and prone to convergence. Others, such as the temporal bone, are thought to reflect more accurately phylogenetic relationships. Direct testing of these hypotheses was not possible until the advent of large genetic data sets. The few relevant studies in human populations have had intriguing but possibly conflicting results, probably partly due to methodological differences and to the small numbers of populations used. Here we use three-dimensional (3D) geometric morphometrics methods to test explicitly the ability of cranial shape, size, and relative position/orientation of cranial regions to track population history and climate. Morphological distances among 13 recent human populations were calculated from four 3D landmark data sets, respectively reflecting facial, neurocranial, and temporal bone shape; shape and relative position; overall cranial shape; and centroid sizes. These distances were compared to neutral genetic and climatic distances among the same, or closely matched, populations. Results indicate that neurocranial and temporal bone shape track neutral genetic distances, while facial shape reflects climate; centroid size shows a weak association with climatic variables; and relative position/orientation of cranial regions does not appear correlated with any of these factors. Because different cranial regions preserve population history and climate signatures differentially, caution is suggested when using cranial anatomy for phylogenetic reconstruction. Copyright (c) 2006 Wiley-Liss, Inc.

Novel Anthropometry Based on 3D-Bodyscans Applied to a Large Population Based Cohort.

PubMed

Löffler-Wirth, Henry; Willscher, Edith; Ahnert, Peter; Wirkner, Kerstin; Engel, Christoph; Loeffler, Markus; Binder, Hans

2016-01-01

Three-dimensional (3D) whole body scanners are increasingly used as precise measuring tools for the rapid quantification of anthropometric measures in epidemiological studies. We analyzed 3D whole body scanning data of nearly 10,000 participants of a cohort collected from the adult population of Leipzig, one of the largest cities in Eastern Germany. We present a novel approach for the systematic analysis of this data which aims at identifying distinguishable clusters of body shapes called body types. In the first step, our method aggregates body measures provided by the scanner into meta-measures, each representing one relevant dimension of the body shape. In a next step, we stratified the cohort into body types and assessed their stability and dependence on the size of the underlying cohort. Using self-organizing maps (SOM) we identified thirteen robust meta-measures and fifteen body types comprising between 1 and 18 percent of the total cohort size. Thirteen of them are virtually gender specific (six for women and seven for men) and thus reflect most abundant body shapes of women and men. Two body types include both women and men, and describe androgynous body shapes that lack typical gender specific features. The body types disentangle a large variability of body shapes enabling distinctions which go beyond the traditional indices such as body mass index, the waist-to-height ratio, the waist-to-hip ratio and the mortality-hazard ABSI-index. In a next step, we will link the identified body types with disease predispositions to study how size and shape of the human body impact health and disease.

Edge Length and Surface Area of a Blank: Experimental Assessment of Measures, Size Predictions and Utility

PubMed Central

Dogandžić, Tamara; Braun, David R.; McPherron, Shannon P.

2015-01-01

Blank size and form represent one of the main sources of variation in lithic assemblages. They reflect economic properties of blanks and factors such as efficiency and use life. These properties require reliable measures of size, namely edge length and surface area. These measures, however, are not easily captured with calipers. Most attempts to quantify these features employ estimates; however, the efficacy of these estimations for measuring critical features such as blank surface area and edge length has never been properly evaluated. In addition, these parameters are even more difficult to acquire for retouched implements as their original size and hence indication of their previous utility have been lost. It has been suggested, in controlled experimental conditions, that two platform variables, platform thickness and exterior platform angle, are crucial in determining blank size and shape meaning that knappers can control the interaction between size and efficiency by selecting specific core angles and controlling where fracture is initiated. The robustness of these models has rarely been tested and confirmed in context other than controlled experiments. In this paper, we evaluate which currently employed caliper measurement methods result in the highest accuracy of size estimations of blanks, and we evaluate how platform variables can be used to indirectly infer aspects of size on retouched artifacts. Furthermore, we investigate measures of different platform management strategies that control the shape and size of artifacts. To investigate these questions, we created an experimental lithic assemblage, we digitized images to calculate 2D surface area and edge length, which are used as a point of comparison for the caliper measurements and additional analyses. The analysis of aspects of size determinations and the utility of blanks contributes to our understanding of the technological strategies of prehistoric knappers and what economic decisions they made during process of blank production. PMID:26332773

The Study of Bose-Einstein correlation in deep inelastic mu - nucleon and mu - nucleus scattering at 465-GeV/C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Rurngsheng

1994-01-01

The Bose-Einstein correlation between two like-sign charged pions was studied in deep inelastic muon nucleon and nucleus interactions. The goals for this study were to measure nuclear effects on the size and shape of the pion emission source and the dependence of these values on the event kinematical variables. Two parametrization models (Goldhaber and Kopylov-Podgorestskii) have been used for this study. The Goldhaber parametrization gives the radius ofthe pion emission region ofrg = 0.63 ± 0.04 fm and for the chaoticity parameter .A = 0.39 ± 0.03. Using the Kopylov-Podgorestskii parameterization yields rk = 1.8 ± 0.72 ±, .A =more » 0.34 ± 0.05 and for the pion source lifetime of T= 0.75 ± 0.18 fm. A double enhancement which represents two source size distribution was observed with a smaller size of 0.51 ± 0.06 ± 0.04 fm and a bigger second size of 1.53 ± 0.39 ± 0.28 fm. The results of this analysis show the Goldhaber parametrization is preferable to explain the source distribution. The Goldhaber parametrization was used for the further studies. The data are compatible with an oblate shape of the pion emission region with not any nuclear effect on the source size and the shape. A decreasing source size has been observed with increasing Zbj as well as with increasing Q2. No dependence for Bose-Einstein effect on other kinematical variables, v and W 2 , is seen. No nuclear effect for the dependence on event kinematical variables, Zbj, W 2, v, and Q2 has been found. This thesis is based on the data collected in the 1990-91 Fermilab experiment E665 fixed target run period and the reconstruction is completed in 1993. The organization of this thesis is as follow: The first chapter describes a brief introduction of experimental and theoretical approach for studying the Bose-Einstein correlation and the evidence from other experiments. Chapter two describes the experimental apparatus which used to gather the data for this analysis. The procedure used to reconstruct raw data into events with kinematical variables and the simulation of Monte-Carlo events is described in chapter three. Chapter four describes the selection of events and tracks used for the Bose-Einstein correlation analysis and the Monte-Carlo studies for understanding the quality of data. The analysis of Bose-Einstein correlation and the results of the analysis along with the conclusions are described in chapter five.« less

Shape Optimization of Supersonic Turbines Using Response Surface and Neural Network Methods

NASA Technical Reports Server (NTRS)

Papila, Nilay; Shyy, Wei; Griffin, Lisa W.; Dorney, Daniel J.

2001-01-01

Turbine performance directly affects engine specific impulse, thrust-to-weight ratio, and cost in a rocket propulsion system. A global optimization framework combining the radial basis neural network (RBNN) and the polynomial-based response surface method (RSM) is constructed for shape optimization of a supersonic turbine. Based on the optimized preliminary design, shape optimization is performed for the first vane and blade of a 2-stage supersonic turbine, involving O(10) design variables. The design of experiment approach is adopted to reduce the data size needed by the optimization task. It is demonstrated that a major merit of the global optimization approach is that it enables one to adaptively revise the design space to perform multiple optimization cycles. This benefit is realized when an optimal design approaches the boundary of a pre-defined design space. Furthermore, by inspecting the influence of each design variable, one can also gain insight into the existence of multiple design choices and select the optimum design based on other factors such as stress and materials considerations.

Efficient Simulation of Wing Modal Response: Application of 2nd Order Shape Sensitivities and Neural Networks

NASA Technical Reports Server (NTRS)

Kapania, Rakesh K.; Liu, Youhua

2000-01-01

At the preliminary design stage of a wing structure, an efficient simulation, one needing little computation but yielding adequately accurate results for various response quantities, is essential in the search of optimal design in a vast design space. In the present paper, methods of using sensitivities up to 2nd order, and direct application of neural networks are explored. The example problem is how to decide the natural frequencies of a wing given the shape variables of the structure. It is shown that when sensitivities cannot be obtained analytically, the finite difference approach is usually more reliable than a semi-analytical approach provided an appropriate step size is used. The use of second order sensitivities is proved of being able to yield much better results than the case where only the first order sensitivities are used. When neural networks are trained to relate the wing natural frequencies to the shape variables, a negligible computation effort is needed to accurately determine the natural frequencies of a new design.

Biotemplating pores with size and shape diversity for Li-oxygen Battery Cathodes.

PubMed

Oh, Dahyun; Ozgit-Akgun, Cagla; Akca, Esin; Thompson, Leslie E; Tadesse, Loza F; Kim, Ho-Cheol; Demirci, Gökhan; Miller, Robert D; Maune, Hareem

2017-04-04

Synthetic porogens provide an easy way to create porous structures, but their usage is limited due to synthetic difficulties, process complexities and prohibitive costs. Here we investigate the use of bacteria, sustainable and naturally abundant materials, as a pore template. The bacteria require no chemical synthesis, come in variable sizes and shapes, degrade easier and are approximately a million times cheaper than conventional porogens. We fabricate free standing porous multiwalled carbon nanotube (MWCNT) films using cultured, harmless bacteria as porogens, and demonstrate substantial Li-oxygen battery performance improvement by porosity control. Pore volume as well as shape in the cathodes were easily tuned to improve oxygen evolution efficiency by 30% and double the full discharge capacity in repeated cycles compared to the compact MWCNT electrode films. The interconnected pores produced by the templates greatly improve the accessibility of reactants allowing the achievement of 4,942 W/kg (8,649 Wh/kg) at 2 A/g e (1.7 mA/cm 2 ).

Biotemplating pores with size and shape diversity for Li-oxygen Battery Cathodes

PubMed Central

Oh, Dahyun; Ozgit-Akgun, Çagla; Akca, Esin; Thompson, Leslie E.; Tadesse, Loza F.; Kim, Ho-Cheol; Demirci, Gökhan; Miller, Robert D.; Maune, Hareem

2017-01-01

Synthetic porogens provide an easy way to create porous structures, but their usage is limited due to synthetic difficulties, process complexities and prohibitive costs. Here we investigate the use of bacteria, sustainable and naturally abundant materials, as a pore template. The bacteria require no chemical synthesis, come in variable sizes and shapes, degrade easier and are approximately a million times cheaper than conventional porogens. We fabricate free standing porous multiwalled carbon nanotube (MWCNT) films using cultured, harmless bacteria as porogens, and demonstrate substantial Li-oxygen battery performance improvement by porosity control. Pore volume as well as shape in the cathodes were easily tuned to improve oxygen evolution efficiency by 30% and double the full discharge capacity in repeated cycles compared to the compact MWCNT electrode films. The interconnected pores produced by the templates greatly improve the accessibility of reactants allowing the achievement of 4,942 W/kg (8,649 Wh/kg) at 2 A/ge (1.7 mA/cm2). PMID:28374862

Sampling errors in the estimation of empirical orthogonal functions. [for climatology studies

NASA Technical Reports Server (NTRS)

North, G. R.; Bell, T. L.; Cahalan, R. F.; Moeng, F. J.

1982-01-01

Empirical Orthogonal Functions (EOF's), eigenvectors of the spatial cross-covariance matrix of a meteorological field, are reviewed with special attention given to the necessary weighting factors for gridded data and the sampling errors incurred when too small a sample is available. The geographical shape of an EOF shows large intersample variability when its associated eigenvalue is 'close' to a neighboring one. A rule of thumb indicating when an EOF is likely to be subject to large sampling fluctuations is presented. An explicit example, based on the statistics of the 500 mb geopotential height field, displays large intersample variability in the EOF's for sample sizes of a few hundred independent realizations, a size seldom exceeded by meteorological data sets.

[Differentiation by geometric morphometrics among 11 Anopheles (Nyssorhynchus) in Colombia].

PubMed

Calle, David Alonso; Quiñones, Martha Lucía; Erazo, Holmes Francisco; Jaramillo, Nicolás

2008-09-01

The correct identification of the Anopheles species of the subgenus Nyssorhynchus is important because this subgenus includes the main malaria vectors in Colombia. This information is necessary for focusing a malaria control program. Geometric morphometrics were used to evaluate morphometric variation of 11 species of subgenus Nyssorhynchus present in Colombia and to distinguish females of each species. Materials and methods. The specimens were obtained from series and family broods from females collected with protected human hosts as attractants. The field collected specimens and their progeny were identified at each of the associated stages by conventional keys. For some species, wild females were used. Landmarks were selected on wings from digital pictures from 336 individuals, and digitized with coordinates. The coordinate matrix was processed by generalized Procrustes analysis which generated size and shape variables, free of non-biological variation. Size and shape variables were analyzed by univariate and multivariate statistics. The subdivision of subgenus Nyssorhynchus in sections is not correlated with wing shape. Discriminant analyses correctly classified 97% of females in the section Albimanus and 86% in the section Argyritarsis. In addition, these methodologies allowed the correct identification of 3 sympatric species from Putumayo which have been difficult to identify in the adult female stage. The geometric morphometrics were demonstrated to be a very useful tool as an adjunct to taxonomy of females the use of this method is recommended in studies of the subgenus Nyssorhynchus in Colombia.

Differential adaptation to a harsh granite outcrop habitat between sympatric Mimulus species.

PubMed

Ferris, Kathleen G; Willis, John H

2018-03-31

Understanding which environmental variables and traits underlie adaptation to harsh environments is difficult because many traits evolve simultaneously as populations or species diverge. Here, we investigate the ecological variables and traits that underlie Mimulus laciniatus' adaptation to granite outcrops compared to its sympatric, mesic-adapted progenitor, Mimulus guttatus. We use fine-scale measurements of soil moisture and herbivory to examine differences in selective forces between the species' habitats, and measure selection on flowering time, flower size, plant height, and leaf shape in a reciprocal transplant using M. laciniatus × M. guttatus F 4 hybrids. We find that differences in drought and herbivory drive survival differences between habitats, that M. laciniatus and M. guttatus are each better adapted to their native habitat, and differential habitat selection on flowering time, plant stature, and leaf shape. Although early flowering time, small stature, and lobed leaf shape underlie plant fitness in M. laciniatus' seasonally dry environment, increased plant size is advantageous in a competitive mesic environment replete with herbivores like M. guttatus'. Given that we observed divergent selection between habitats in the direction of species differences, we conclude that adaptation to different microhabitats is an important component of reproductive isolation in this sympatric species pair. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Advances in the simulation and automated measurement of well-sorted granular material: 1. Simulation

USGS Publications Warehouse

Daniel Buscombe,; Rubin, David M.

2012-01-01

1. In this, the first of a pair of papers which address the simulation and automated measurement of well-sorted natural granular material, a method is presented for simulation of two-phase (solid, void) assemblages of discrete non-cohesive particles. The purpose is to have a flexible, yet computationally and theoretically simple, suite of tools with well constrained and well known statistical properties, in order to simulate realistic granular material as a discrete element model with realistic size and shape distributions, for a variety of purposes. The stochastic modeling framework is based on three-dimensional tessellations with variable degrees of order in particle-packing arrangement. Examples of sediments with a variety of particle size distributions and spatial variability in grain size are presented. The relationship between particle shape and porosity conforms to published data. The immediate application is testing new algorithms for automated measurements of particle properties (mean and standard deviation of particle sizes, and apparent porosity) from images of natural sediment, as detailed in the second of this pair of papers. The model could also prove useful for simulating specific depositional structures found in natural sediments, the result of physical alterations to packing and grain fabric, using discrete particle flow models. While the principal focus here is on naturally occurring sediment and sedimentary rock, the methods presented might also be useful for simulations of similar granular or cellular material encountered in engineering, industrial and life sciences.

The Effect of Heterogeneity on Numerical Ordering in Rhesus Monkeys

ERIC Educational Resources Information Center

Cantlon, Jessica F.; Brannon, Elizabeth M.

2006-01-01

We investigated how within-stimulus heterogeneity affects the ability of rhesus monkeys to order pairs of the numerosities 1 through 9. Two rhesus monkeys were tested in a touch screen task where the variability of elements within each visual array was systematically varied by allowing elements to vary in color, size, shape, or any combination of…

Elbow joint variability for different hand positions of the round off in gymnastics.

PubMed

Farana, Roman; Irwin, Gareth; Jandacka, Daniel; Uchytil, Jaroslav; Mullineaux, David R

2015-02-01

The aim of the present study was to conduct within-gymnast analyses of biological movement variability in impact forces, elbow joint kinematics and kinetics of expert gymnasts in the execution of the round-off with different hand positions. Six international level female gymnasts performed 10 trials of the round-off from a hurdle step to a back-handspring using two hand potions: parallel and T-shape. Two force plates were used to determine ground reaction forces. Eight infrared cameras were employed to collect the kinematic data automatically. Within gymnast variability was calculated using biological coefficient of variation (BCV) discretely for ground reaction force, kinematic and kinetic measures. Variability of the continuous data was quantified using coefficient of multiple correlations (CMC). Group BCV and CMC were calculated and T-test with effect size statistics determined differences between the variability of the two techniques examined in this study. The major observation was a higher level of biological variability in the elbow joint abduction angle and adduction moment of force in the T-shaped hand position. This finding may lead to a reduced repetitive abduction stress and thus protect the elbow joint from overload. Knowledge of the differences in biological variability can inform clinicians and practitioners with effective skill selection. Copyright © 2014 Elsevier B.V. All rights reserved.

Finite element analysis of 6 large PMMA skull reconstructions: A multi-criteria evaluation approach

PubMed Central

Ridwan-Pramana, Angela; Marcián, Petr; Borák, Libor; Narra, Nathaniel; Forouzanfar, Tymour; Wolff, Jan

2017-01-01

In this study 6 pre-operative designs for PMMA based reconstructions of cranial defects were evaluated for their mechanical robustness using finite element modeling. Clinical experience and engineering principles were employed to create multiple plan options, which were subsequently computationally analyzed for mechanically relevant parameters under 50N loads: stress, strain and deformation in various components of the assembly. The factors assessed were: defect size, location and shape. The major variable in the cranioplasty assembly design was the arrangement of the fixation plates. An additional study variable introduced was the location of the 50N load within the implant area. It was found that in smaller defects, it was simpler to design a symmetric distribution of plates and under limited variability in load location it was possible to design an optimal for expected loads. However, for very large defects with complex shapes, the variability in the load locations introduces complications to the intuitive design of the optimal assembly. The study shows that it can be beneficial to incorporate multi design computational analyses to decide upon the most optimal plan for a clinical case. PMID:28609471

Finite element analysis of 6 large PMMA skull reconstructions: A multi-criteria evaluation approach.

PubMed

Ridwan-Pramana, Angela; Marcián, Petr; Borák, Libor; Narra, Nathaniel; Forouzanfar, Tymour; Wolff, Jan

2017-01-01

In this study 6 pre-operative designs for PMMA based reconstructions of cranial defects were evaluated for their mechanical robustness using finite element modeling. Clinical experience and engineering principles were employed to create multiple plan options, which were subsequently computationally analyzed for mechanically relevant parameters under 50N loads: stress, strain and deformation in various components of the assembly. The factors assessed were: defect size, location and shape. The major variable in the cranioplasty assembly design was the arrangement of the fixation plates. An additional study variable introduced was the location of the 50N load within the implant area. It was found that in smaller defects, it was simpler to design a symmetric distribution of plates and under limited variability in load location it was possible to design an optimal for expected loads. However, for very large defects with complex shapes, the variability in the load locations introduces complications to the intuitive design of the optimal assembly. The study shows that it can be beneficial to incorporate multi design computational analyses to decide upon the most optimal plan for a clinical case.

First principle study of electronic nanoscale structure of In x Ga1- x P with variable size, shape and alloying percentage

NASA Astrophysics Data System (ADS)

Hussein, M. T.; Kasim, T.; Abdulsattar, M. A.

2013-11-01

In present work, we investigate electronic properties of alloying percentage of In x Ga1- x P compound with different sizes of superlattice large unit cell (LUC) method with 8, 16, 54, and 64 nanocrystals core atoms. The size and type of alloying compound are varied so that it can be tuned to a required application. To determine properties of indium gallium phosphide nanocrystals density functional theory at the generalized-gradient approximation level coupled with LUC method is used to simulate electronic structure of zinc blende indium gallium phosphide nanocrystals that have dimensions around 2-2.8 nm. The calculated properties include lattice constant, energy gap, valence band width, cohesive energy, density of states (DOS) etc. Results show that laws that are applied at microscale alloying percentage are no more applicable at the present nanoscale. Results also show that size, shape and quantum effects are strong. Many properties fluctuate at nanoscale while others converge to definite values. DOS summarizes many of the above quantities.

Microstructural investigations on carbonate fault core rocks in active extensional fault zones from the central Apennines (Italy)

NASA Astrophysics Data System (ADS)

Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio

2017-04-01

The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub-rounded), and (2) very fine-grained gouges (< 1 mm) localized along major and minor mirror-like slip surfaces. Damage zones mostly consist of fractured rocks and, locally, pulverized rocks. Collectively, field observations and laboratory analyses indicate that within the fault cores of the studied fault zones, grain size progressively decreases approaching the master slip surfaces. Furthermore, grain shape changes from very angular to sub-rounded clasts moving toward the master slip surfaces. These features suggest that the progressive evolution of grain size and shape distributions within fault cores may have determined the development of strain localization by the softening and cushioning effects of smaller particles in loose fault rocks.

Can high resolution topographic surveys provide reliable grain size estimates?

NASA Astrophysics Data System (ADS)

Pearson, Eleanor; Smith, Mark; Klaar, Megan; Brown, Lee

2017-04-01

High resolution topographic surveys contain a wealth of information that is not always exploited in the generation of Digital Elevation Models (DEMs). In particular, several authors have related sub-grid scale topographic variability (or 'surface roughness') to particle grain size by deriving empirical relationships between the two. Such relationships would permit rapid analysis of the spatial distribution of grain size over entire river reaches, providing data to drive distributed hydraulic models and revolutionising monitoring of river restoration projects. However, comparison of previous roughness-grain-size relationships shows substantial variability between field sites and do not take into account differences in patch-scale facies. This study explains this variability by identifying the factors that influence roughness-grain-size relationships. Using 275 laboratory and field-based Structure-from-Motion (SfM) surveys, we investigate the influence of: inherent survey error; irregularity of natural gravels; particle shape; grain packing structure; sorting; and form roughness on roughness-grain-size relationships. A suite of empirical relationships is presented in the form of a decision tree which improves estimations of grain size. Results indicate that the survey technique itself is capable of providing accurate grain size estimates. By accounting for differences in patch facies, R2 was seen to improve from 0.769 to R2 > 0.9 for certain facies. However, at present, the method is unsuitable for poorly sorted gravel patches. In future, a combination of a surface roughness proxy with photosieving techniques using SfM-derived orthophotos may offer improvements on using either technique individually.

Particle shape impacts export and fate in the ocean through interactions with the globally abundant appendicularian Oikopleura dioica.

PubMed

Conley, Keats R; Sutherland, Kelly R

2017-01-01

Marine microbes exhibit highly varied, often non-spherical shapes that have functional significance for essential processes, including nutrient acquisition and sinking rates. There is a surprising absence of data, however, on how cell shape affects grazing, which is crucial for predicting the fate of oceanic carbon. We used synthetic spherical and prolate spheroid microbeads to isolate the effect of particle length-to-width ratios on grazing and fate in the ocean. Here we show that the shape of microbe-sized particles affects predation by the appendicularian Oikopleura dioica, a globally abundant marine grazer. Using incubation experiments, we demonstrate that shape affects how particles are retained in the house and that the minimum particle diameter is the key variable determining how particles are ingested. High-speed videography revealed the mechanism behind these results: microbe-sized spheroids oriented with the long axis parallel to fluid streamlines, matching the speed and tortuosity of spheres of equivalent width. Our results suggest that the minimum particle diameter determines how elongated prey interact with the feeding-filters of appendicularians, which may help to explain the prevalence of ellipsoidal cells in the ocean, since a cell's increased surface-to-volume ratio does not always increase predation. We provide the first evidence that grazing by appendicularians can cause non-uniform export of different shaped particles, thereby influencing particle fate.

Development for 2D pattern quantification method on mask and wafer

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Toyoda, Yasutaka; Wang, Zhigang

2010-03-01

We have developed the effective method of mask and silicon 2-dimensional metrology. The aim of this method is evaluating the performance of the silicon corresponding to Hotspot on a mask. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. 2-dimensional Shape quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. On the other hand, there is roughness in the silicon shape made from a mass-production line. Moreover, there is variation in the silicon shape. For this reason, quantification of silicon shape is important, in order to estimate the performance of a pattern. In order to quantify, the same shape is equalized in two dimensions. And the method of evaluating based on the shape is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. It is possible to analyze variability of the edge of the same position with high precision. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. - Estimate of the correlativity of shape variability and a process margin. - Determination of two-dimensional variability of pattern. - Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the shape of the same location of Design, Mask, and Silicon in such a viewpoint.

Nonlocal Intracranial Cavity Extraction

PubMed Central

Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

2014-01-01

Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

A National Census of Birth Weight in Purebred Dogs in Italy

PubMed Central

Groppetti, Debora; Pecile, Alessandro; Palestrini, Clara; Marelli, Stefano P.; Boracchi, Patrizia

2017-01-01

Simple Summary Birth weight is a key factor for neonatal mortality and morbidity in most mammalian species. The great morphological variability in size, body weight and breed, as well as in skeletal and cranial conformation makes it challenging to define birth weight standards in dogs. A total of 3293 purebred pups were surveyed to study which maternal aspects can determine birth weight considering head and body shape, size, body weight and breed in bitches, as well as litter size and sex in pups. In our sample, multivariate analysis outcomes suggested that birth weight and litter size were directly proportional to maternal size. The maternal body shape influenced both birth weight and litter size, whereas the maternal head shape had impact only on birth weight. Sex differences in birth weight were found. Birth weight and litter size also varied among breeds. The results of the present study could have practical implications allowing one to identify pups in need of admission to intensive nursing care, as occurs in humans. A deeper knowledge of the factors that significantly influence birth weight could positively affect the canine breeding management helping to prevent and reduce neonatal mortality. Abstract Despite increasing professionalism in dog breeding, the physiological range of birth weight in this species remains unclear. Low birth weight can predispose to neonatal mortality and growth deficiencies in humans. To date, the influence of the morphotype on birth weight has never been studied in dogs. For this purpose, an Italian census of birth weight was collected from 3293 purebred pups based on maternal morphotype, size, body weight and breed, as well as on litter size and sex of pups. Multivariate analysis outcomes showed that birth weight (p < 0.001) and litter size (p < 0.05) increased with maternal size and body weight. Birth weight was also influenced by the maternal head and body shape, with brachycephalic and brachymorph dogs showing the heaviest and the lightest pups, respectively (p < 0.001). Birth weight decreased with litter size (p < 0.001), and male pups were heavier than females (p < 0.001). These results suggest that canine morphotype, not only maternal size and body weight, can affect birth weight and litter size with possible practical implications in neonatal assistance. PMID:28556821

Bone Marrow Stem Cells and Ear Framework Reconstruction.

PubMed

Karimi, Hamid; Emami, Seyed-Abolhassan; Olad-Gubad, Mohammad-Kazem

2016-11-01

Repair of total human ear loss or congenital lack of ears is one of the challenging issues in plastic and reconstructive surgery. The aim of the present study was 3D reconstruction of the human ear with cadaveric ear cartilages seeded with human mesenchymal stem cells. We used cadaveric ear cartilages with preserved perichondrium. The samples were divided into 2 groups: group A (cartilage alone) and group B (cartilage seeded with a mixture of fibrin powder and mesenchymal stem cell [1,000,000 cells/cm] used and implanted in back of 10 athymic rats). After 12 weeks, the cartilages were removed and shape, size, weight, flexibility, and chondrocyte viability were evaluated. P value <0.05 was considered significant. In group A, size and weight of cartilages clearly reduced (P < 0.05) and then shape and flexibility (torsion of cartilages in clockwise and counterclockwise directions) were evaluated, which were found to be significantly reduced (P > 0.05). After staining with hematoxylin and eosin and performing microscopic examination, very few live chondrocytes were found in group A. In group B, size and weight of samples were not changed (P < 0.05); the shape and flexibility of samples were well maintained (P < 0.05) and on performing microscopic examination of cartilage samples, many live chondrocytes were found in cartilage (15-20 chondrocytes in each microscopic field). In samples with human stem cell, all variables (size, shape, weight, and flexibility) were significantly maintained and abundant live chondrocytes were found on performing microscopic examination. This method may be used for reconstruction of full defect of auricles in humans.

Neuronal density, size and shape in the human anterior cingulate cortex: a comparison of Nissl and NeuN staining.

PubMed

Gittins, Rebecca; Harrison, Paul J

2004-03-15

There are an increasing number of quantitative morphometric studies of the human cerebral cortex, especially as part of comparative investigations of major psychiatric disorders. In this context, the present study had two aims. First, to provide quantitative data regarding key neuronal morphometric parameters in the anterior cingulate cortex. Second, to compare the results of conventional Nissl staining with those observed after immunostaining with NeuN, an antibody becoming widely used as a selective neuronal marker. We stained adjacent sections of area 24b from 16 adult brains with cresyl violet or NeuN. We measured the density of pyramidal and non-pyramidal neurons, and the size and shape of pyramidal neurons, in laminae II, III, Va, Vb and VI, using two-dimensional counting methods. Strong correlations between the two modes of staining were seen for all variables. However, NeuN gave slightly higher estimates of neuronal density and size, and a more circular perikaryal shape. Brain pH was correlated with neuronal size, measured with both methods, and with neuronal shape. Age and post-mortem interval showed no correlations with any parameter. These data confirm the value of NeuN as a tool for quantitative neuronal morphometric studies in routinely processed human brain tissue. Absolute values are highly correlated between NeuN and cresyl violet stains, but cannot be interchanged. NeuN may be particularly useful when it is important to distinguish small neurons from glia, such as in cytoarchitectural studies of the cerebral cortex in depression and schizophrenia.

Occupancy in continuous habitat

USGS Publications Warehouse

Efford, Murray G.; Dawson, Deanna K.

2012-01-01

The probability that a site has at least one individual of a species ('occupancy') has come to be widely used as a state variable for animal population monitoring. The available statistical theory for estimation when detection is imperfect applies particularly to habitat patches or islands, although it is also used for arbitrary plots in continuous habitat. The probability that such a plot is occupied depends on plot size and home-range characteristics (size, shape and dispersion) as well as population density. Plot size is critical to the definition of occupancy as a state variable, but clear advice on plot size is missing from the literature on the design of occupancy studies. We describe models for the effects of varying plot size and home-range size on expected occupancy. Temporal, spatial, and species variation in average home-range size is to be expected, but information on home ranges is difficult to retrieve from species presence/absence data collected in occupancy studies. The effect of variable home-range size is negligible when plots are very large (>100 x area of home range), but large plots pose practical problems. At the other extreme, sampling of 'point' plots with cameras or other passive detectors allows the true 'proportion of area occupied' to be estimated. However, this measure equally reflects home-range size and density, and is of doubtful value for population monitoring or cross-species comparisons. Plot size is ill-defined and variable in occupancy studies that detect animals at unknown distances, the commonest example being unlimited-radius point counts of song birds. We also find that plot size is ill-defined in recent treatments of "multi-scale" occupancy; the respective scales are better interpreted as temporal (instantaneous and asymptotic) rather than spatial. Occupancy is an inadequate metric for population monitoring when it is confounded with home-range size or detection distance.

Novel Anthropometry Based on 3D-Bodyscans Applied to a Large Population Based Cohort

PubMed Central

Löffler-Wirth, Henry; Willscher, Edith; Ahnert, Peter; Wirkner, Kerstin; Engel, Christoph; Loeffler, Markus; Binder, Hans

2016-01-01

Three-dimensional (3D) whole body scanners are increasingly used as precise measuring tools for the rapid quantification of anthropometric measures in epidemiological studies. We analyzed 3D whole body scanning data of nearly 10,000 participants of a cohort collected from the adult population of Leipzig, one of the largest cities in Eastern Germany. We present a novel approach for the systematic analysis of this data which aims at identifying distinguishable clusters of body shapes called body types. In the first step, our method aggregates body measures provided by the scanner into meta-measures, each representing one relevant dimension of the body shape. In a next step, we stratified the cohort into body types and assessed their stability and dependence on the size of the underlying cohort. Using self-organizing maps (SOM) we identified thirteen robust meta-measures and fifteen body types comprising between 1 and 18 percent of the total cohort size. Thirteen of them are virtually gender specific (six for women and seven for men) and thus reflect most abundant body shapes of women and men. Two body types include both women and men, and describe androgynous body shapes that lack typical gender specific features. The body types disentangle a large variability of body shapes enabling distinctions which go beyond the traditional indices such as body mass index, the waist-to-height ratio, the waist-to-hip ratio and the mortality-hazard ABSI-index. In a next step, we will link the identified body types with disease predispositions to study how size and shape of the human body impact health and disease. PMID:27467550

Evaluation of the DSM-5 Severity Indicator for Binge Eating Disorder in a Community Sample

PubMed Central

Grilo, Carlos M.; Ivezaj, Valentina; White, Marney A.

2015-01-01

Research has examined various aspects of the diagnostic criteria for binge-eating disorder (BED) but has yet to evaluate the DSM-5 severity criterion. This study examined the DSM-5 severity criterion for BED based on binge-eating frequency and tested an alternative severity specifier based on overvaluation of shape/weight. 338 community volunteers categorized with DSM-5 BED completed a battery of self-report instruments. Participants were categorized first using DSM-5 severity levels and second by shape/weight overvaluation and were compared on clinical variables. 264 (78.1%) participants were categorized as mild, 67 (19.8%) as moderate, 6 (1.8%) as severe, and 1 (0.3%) as extreme. Analyses comparing mild and moderate severity groups revealed no significant differences in demographic variables or BMI; moderate severity group had greater eating-disorder psychopathology (small effect-sizes) but not depression than mild group. Participants with overvaluation (N=196; 60.1%) versus without (N=130; 39.9%) did not differ significantly in age, sex, BMI, or binge-eating frequency. Overvaluation group had significantly greater eating-disorder psychopathology and depression than non-overvaluation group. The greater eating-disorder and depression levels (medium-to-large effect-sizes) persisted after adjusting for ethnicity/race and binge-eating severity/frequency, without attenuation of effect-sizes. Findings from this non-clinical community sample provide support for overvaluation of shape/weight as a specifier for BED as it provides stronger information about severity than the DSM-5 rating based on binge-eating. Future research should include treatment-seeking patients with BED to test the utility of DSM-5 severity specifiers and include broader clinical validators. PMID:25701802

Evaluation of the DSM-5 severity indicator for binge eating disorder in a clinical sample

PubMed Central

Grilo, Carlos M.; Ivezaj, Valentina; White, Marney A.

2015-01-01

Objective This study tested the new DSM-5 severity criterion for binge eating disorder (BED) based on frequency of binge-eating in a clinical sample. This study also tested overvaluation of shape/weight as an alternative severity specifier. Method Participants were 834 treatment-seeking adults diagnosed with DSM-5 BED using semistructured diagnostic and eating-disorder interviews. Participants sub-grouped based on DSM-5 severity levels and on overvaluation of shape/weight were compared on demographic and clinical variables. Results Based on DSM-5 severity definitions, 331 (39.7%) participants were categorized as mild, 395 (47.5%) as moderate, 83 (10.0%) as severe, and 25 (3.0%) as extreme. Analyses comparing three (mild, moderate, and severe/extreme) severity groups revealed no significant differences in demographic variables or body mass index (BMI). Analyses revealed significantly higher eating-disorder psychopathology in the severe/extreme than moderate and mild groups and higher depression in moderate and severe/extreme groups than the mild group; effect sizes were small. Participants characterized with overvaluation (N = 449; 54%) versus without overvaluation (N = 384; 46%) did not differ significantly in age, sex, BMI, or binge-eating frequency, but had significantly greater eating-disorder psychopathology and depression. The robustly greater eating-disorder psychopathology and depression levels (medium-to-large effect sizes) in the overvaluation group was observed without attenuation of effect sizes after adjusting for ethnicity/race and binge-eating severity/frequency. Conclusions Our findings provide support for overvaluation of shape/weight as a severity specifier for BED as it provides stronger information about the severity of homogeneous groupings of patients than the DSM-5 rating based on binge-eating. PMID:26114779

Quantitative analyses of variability in normal vaginal shape and dimension on MR images

PubMed Central

Luo, Jiajia; Betschart, Cornelia; Ashton-Miller, James A.; DeLancey, John O. L.

2016-01-01

Introduction and hypothesis We present a technique for quantifying inter-individual variability in normal vaginal shape, axis, and dimension, and report findings in healthy women. Methods Eighty women (age: 28~70 years) with normal pelvic organ support underwent supine, multi-planar proton-density MRI. Vaginal width was assessed at five evenly-spaced locations, and vaginal axis, length, and surface area were quantified via ImageJ and MATLAB. Results The mid-sagittal plane angles, relative to the horizontal, of three vaginal axes were 90± 11, 72± 21, and 41± 22° (caudal to cranial, p < 0.001). The mean (± SD) vaginal widths were 17± 5, 24± 4, 30± 7, 41± 9, and 45± 12 mm at the five locations (caudal to cranial, p < 0.001). Mid-sagittal lengths for anterior and posterior vaginal walls were 63± 9 and 98 ± 18 mm respectively. The vaginal surface area was 72 ± 21 cm2 (range: 34 ~ 164 cm2). The coefficient of determination between any demographic variable and any vaginal dimension did not exceed 0.16. Conclusions Large variations in normal vaginal shape, axis, and dimensions were not explained by body size or other demographic variables. This variation has implications for reconstructive surgery, intravaginal and surgical product design, and vaginal drug delivery. PMID:26811115

Possible pseudogout in two dogs.

PubMed

Forsyth, S F; Thompson, K G; Donald, J J

2007-03-01

Pseudogout, the acute form of calcium pyrophosphate deposition disease, is a common condition in elderly human beings and is characterised by the sudden onset of intense joint pain and synovitis. It is rarely identified in animals but was diagnosed in two dogs that presented with acute lameness and pyrexia. Cytology of the synovial fluid showed a mildly elevated cell count with both non-degenerate neutrophils and mononuclear cells present. Many of the mononuclear cells and occasional neutrophils contained square or rhomboid-shaped crystals that were variable in shape and size and weakly birefringent on examination under polarised light. Clinical signs resolved following treatment with prednisolone.

Diagnostics of wear in aeronautical systems

NASA Technical Reports Server (NTRS)

Wedeven, L. D.

1979-01-01

Maintenance costs associated with the transmissions and drive train greatly increase the maintenance burden and failure risk. Detection measurements fall under two general categories of vibration and particle detectors. The latter are more amenable to tracking wear. Wear debris analysis can supply a great deal of information such as: particle concentration, rate of change in concentration, composition, particle size and shape, principal metals, etc. It is not economically feasible to monitor all variables. At least one role of the lubrication and wear specialist is to provide guidance in selecting the most appropriate variables to monitor.

Validation of a sterilization dose for products manufactured using a 3D printer

NASA Astrophysics Data System (ADS)

Wangsgard, Wendy; Winters, Martell

2018-02-01

As more healthcare products are personalized, the use of unique, patient-specific products will increase. Some of these are manufactured using a 3D printing process (also known as additive manufacturing) for either polymers or metals. For these products, processes such as sterilization validations must be handled in a different manner. The concepts typically used are still relevant but are approached from an alternative perspective to account for a potential production batch size of one, and for the great variability that can occur in size and shape of a product.

Natural variation of fecundity components in a widespread plant with dimorphic seeds

NASA Astrophysics Data System (ADS)

Braza, Rita; Arroyo, J.; García, M. B.

2010-09-01

The number and size of seeds are the basis of the quantity and quality components of female reproductive fitness in plants, playing a central role in the evolutionary ecology of life history diversification. In this study we show and analyze the natural variability of several fecundity variables (fruit set, seed production per fruit, seed size, total seed production per plant, and proportion of small seeds) in Plantago coronopus, a widespread, short-lived herb with dimorphic seeds. The structure of such variability was examined at the individual, population (eight locations with different environments within the same region), and life history levels (annual vs perennial), and correlated to soil fertility. There was no divergence associated to the life history for any of the variables studied. Total seed production (the quantity component of female fitness) was correlated with maternal resources, while the size of the large mucilaginous, basal seeds, and the proportion of the small apical seeds (quality component) were more associated to environmental resources. Thus, internal and external resources shape different fitness components, maximizing seed production, and fitting the size and proportion of different kind of seeds to local conditions irrespective of life history. P. coronopus illustrates the versatility of short-lived widespread plants to combine fecundity traits in a flexible manner, in order to increase fitness at each of the many possible habitats they occupy over heterogeneous environments.

Describing wildland surface fuel loading for fire management: A review of approaches, methods and systems

Treesearch

Robert E. Keane

2013-01-01

Wildland fuelbeds are exceptionally complex, consisting of diverse particles of many sizes, types and shapes with abundances and properties that are highly variable in time and space. This complexity makes it difficult to accurately describe, classify, sample and map fuels for wildland fire research and management. As a result, many fire behaviour and effects software...

Preparation of thin film silver fluoride electrodes from constituent elements

NASA Technical Reports Server (NTRS)

Odonnell, P. M.

1972-01-01

The feasibility of preparing thin-film metal fluoride electrodes from the elemental constituents has been demonstrated. Silver fluoride cathodes were prepared by deposition of silver on a conducting graphite substrate followed by fluorination under controlled conditions using elemental fluorine. The resulting electrodes were of high purity, and the variables such as size, shape, and thickness were easily controlled.

A shape-based segmentation method for mobile laser scanning point clouds

NASA Astrophysics Data System (ADS)

Yang, Bisheng; Dong, Zhen

2013-07-01

Segmentation of mobile laser point clouds of urban scenes into objects is an important step for post-processing (e.g., interpretation) of point clouds. Point clouds of urban scenes contain numerous objects with significant size variability, complex and incomplete structures, and holes or variable point densities, raising great challenges for the segmentation of mobile laser point clouds. This paper addresses these challenges by proposing a shape-based segmentation method. The proposed method first calculates the optimal neighborhood size of each point to derive the geometric features associated with it, and then classifies the point clouds according to geometric features using support vector machines (SVMs). Second, a set of rules are defined to segment the classified point clouds, and a similarity criterion for segments is proposed to overcome over-segmentation. Finally, the segmentation output is merged based on topological connectivity into a meaningful geometrical abstraction. The proposed method has been tested on point clouds of two urban scenes obtained by different mobile laser scanners. The results show that the proposed method segments large-scale mobile laser point clouds with good accuracy and computationally effective time cost, and that it segments pole-like objects particularly well.

Shape of Thyroid Cartilage Influences Outcome of Montgomery Medialization Thyroplasty: A Gender Issue.

PubMed

Desuter, Gauthier; Henrard, Sylvie; Van Lith-Bijl, Julie T; Amory, Avigaëlle; Duprez, Thierry; van Benthem, Peter Paul; Sjögren, Elisabeth

2017-03-01

This study aimed to determine whether the shape of the thyroid cartilage and gender influence voice outcomes after a Montgomery thyroplasty implant system (MTIS). A retrospective cohort study was performed on 20 consecutive patients who underwent MTIS. Voice outcome variables were the relative decrease in Voice Handicap Index (%) and the absolute increase in maximum phonation time (MPT) (in seconds). Material variables were the angle between the thyroid cartilage laminae (α-angle), the size of the prosthesis, and a combination of both (the α-ratio). Continuous variables were analyzed using medians and were compared between groups using the Mann-Whitney U test. Factors associated with the outcome variables were assessed by multivariable linear regression. A Pearson coefficient was calculated between material variables. The absolute increase in MPT between the pre- and postoperative period was significantly different between men and women, with a median absolute increase of 11.0 seconds for men and of 1.3 seconds for women (P < 0.001). A strong inverse correlation between the α-ratio and the absolute increase in MPT is observed in all patients, with a Pearson correlation coefficient R = -0.769 (P < 0.001). No factors were significantly associated with the relative Voice Handicap Index decrease in univariable or multivariable analyses. A better Pearson coefficient between the α-angle and the prosthesis size was found for females (0.8 vs 0.71). The MTIS is a good thyroplasty modality for male patients, but inadequate design of MTIS female implants leads to poor MPT outcomes. This represents a gender issue that needs to be further studied and eventually tackled. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Morphometric analysis of developing crowns of maxillary primary second molars and permanent first molars in humans.

PubMed

Peretz, B; Nevis, N; Smith, P

1998-07-01

The purpose of this study was firstly to characterize the changes occurring in size and form of the mineralizing maxillary second primary molar and first permanent molar crowns, and secondly to determine if similar changes in size and form characterize enamel apposition in the crowns of these teeth. Twenty-five primary second molars and 20 maxillary permanent first molars at various stages of development, found in archaeological excavations in Israel, were examined for a number of measured variables using image analyser software. Teeth were divided into two groups according to their stage of development: stage I included all teeth at an early stage of development in which mesiobuccal-cusp height was less than 5 mm for the primary molar and 5.9 mm for the permanent molar; stage 2 included all teeth in later stages of development where mesiobuccal-cusp height was greater than these values. In the primary molar, a significant increase was found between the two stages in almost all variables. Significant correlations were also found between all intercusp distances and the external variables. Strong correlations between height of the mesiobuccal cusp and all external and internal variables were noted in stage 1, but fewer in stage 2. In the permanent tooth, no increase was observed in intercusp distances and very few correlations were found between and among the variables. The results suggest that a change in the shape of the maxillary primary second molar occurs during formation, with the lingual cusp tips moving lingually and distally, and the distobuccal cusp tips moving distally. No change occurs in the shape of the maxillary permanent first molar during crown formation. Growth of the maxillary primary second and permanent first molar crowns occurs in 'bursts' of development.

2D or Not 2D? Testing the Utility of 2D Vs. 3D Landmark Data in Geometric Morphometrics of the Sculpin Subfamily Oligocottinae (Pisces; Cottoidea).

PubMed

Buser, Thaddaeus J; Sidlauskas, Brian L; Summers, Adam P

2018-05-01

We contrast 2D vs. 3D landmark-based geometric morphometrics in the fish subfamily Oligocottinae by using 3D landmarks from CT-generated models and comparing the morphospace of the 3D landmarks to one based on 2D landmarks from images. The 2D and 3D shape variables capture common patterns across taxa, such that the pairwise Procrustes distances among taxa correspond and the trends captured by principal component analysis are similar in the xy plane. We use the two sets of landmarks to test several ecomorphological hypotheses from the literature. Both 2D and 3D data reject the hypothesis that head shape correlates significantly with the depth at which a species is commonly found. However, in taxa where shape variation in the z-axis is high, the 2D shape variables show sufficiently strong distortion to influence the outcome of the hypothesis tests regarding the relationship between mouth size and feeding ecology. Only the 3D data support previous studies which showed that large mouth sizes correlate positively with high percentages of elusive prey in the diet. When used to test for morphological divergence, 3D data show no evidence of divergence, while 2D data show that one clade of oligocottines has diverged from all others. This clade shows the greatest degree of z-axis body depth within Oligocottinae, and we conclude that the inability of the 2D approach to capture this lateral body depth causes the incongruence between 2D and 3D analyses. Anat Rec, 301:806-818, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The Microwave Properties of Simulated Melting Precipitation Particles: Sensitivity to Initial Melting

NASA Technical Reports Server (NTRS)

Johnson, B. T.; Olson, W. S.; Skofronick-Jackson, G.

2016-01-01

A simplified approach is presented for assessing the microwave response to the initial melting of realistically shaped ice particles. This paper is divided into two parts: (1) a description of the Single Particle Melting Model (SPMM), a heuristic melting simulation for ice-phase precipitation particles of any shape or size (SPMM is applied to two simulated aggregate snow particles, simulating melting up to 0.15 melt fraction by mass), and (2) the computation of the single-particle microwave scattering and extinction properties of these hydrometeors, using the discrete dipole approximation (via DDSCAT), at the following selected frequencies: 13.4, 35.6, and 94.0GHz for radar applications and 89, 165.0, and 183.31GHz for radiometer applications. These selected frequencies are consistent with current microwave remote-sensing platforms, such as CloudSat and the Global Precipitation Measurement (GPM) mission. Comparisons with calculations using variable-density spheres indicate significant deviations in scattering and extinction properties throughout the initial range of melting (liquid volume fractions less than 0.15). Integration of the single-particle properties over an exponential particle size distribution provides additional insight into idealized radar reflectivity and passive microwave brightness temperature sensitivity to variations in size/mass, shape, melt fraction, and particle orientation.

The problem with coal-waste dumps inventory in Upper Silesian Coal Basin

NASA Astrophysics Data System (ADS)

Abramowicz, Anna; Chybiorz, Ryszard

2017-04-01

Coal-waste dumps are the side effect of coal mining, which has lasted in Poland for 250 years. They have negative influence on the landscape and the environment, and pollute soil, vegetation and groundwater. Their number, size and shape is changing over time, as new wastes have been produced and deposited changing their shape and enlarging their size. Moreover deposited wastes, especially overburned, are exploited for example road construction, also causing the shape and size change up to disappearing. Many databases and inventory systems were created in order to control these hazards, but some disadvantages prevent reliable statistics. Three representative databases were analyzed according to their structure and type of waste dumps description, classification and visualization. The main problem is correct classification of dumps in terms of their name and type. An additional difficulty is the accurate quantitative description (area and capacity). A complex database was created as a result of comparison, verification of the information contained in existing databases and its supplementation based on separate documentation. A variability analysis of coal-waste dumps over time is also included. The project has been financed from the funds of the Leading National Research Centre (KNOW) received by the Centre for Polar Studies for the period 2014-2018.

Control of minimum member size in parameter-free structural shape optimization by a medial axis approximation

NASA Astrophysics Data System (ADS)

Schmitt, Oliver; Steinmann, Paul

2018-06-01

We introduce a manufacturing constraint for controlling the minimum member size in structural shape optimization problems, which is for example of interest for components fabricated in a molding process. In a parameter-free approach, whereby the coordinates of the FE boundary nodes are used as design variables, the challenging task is to find a generally valid definition for the thickness of non-parametric geometries in terms of their boundary nodes. Therefore we use the medial axis, which is the union of all points with at least two closest points on the boundary of the domain. Since the effort for the exact computation of the medial axis of geometries given by their FE discretization highly increases with the number of surface elements we use the distance function instead to approximate the medial axis by a cloud of points. The approximation is demonstrated on three 2D examples. Moreover, the formulation of a minimum thickness constraint is applied to a sensitivity-based shape optimization problem of one 2D and one 3D model.

Control of minimum member size in parameter-free structural shape optimization by a medial axis approximation

NASA Astrophysics Data System (ADS)

Schmitt, Oliver; Steinmann, Paul

2017-09-01

We introduce a manufacturing constraint for controlling the minimum member size in structural shape optimization problems, which is for example of interest for components fabricated in a molding process. In a parameter-free approach, whereby the coordinates of the FE boundary nodes are used as design variables, the challenging task is to find a generally valid definition for the thickness of non-parametric geometries in terms of their boundary nodes. Therefore we use the medial axis, which is the union of all points with at least two closest points on the boundary of the domain. Since the effort for the exact computation of the medial axis of geometries given by their FE discretization highly increases with the number of surface elements we use the distance function instead to approximate the medial axis by a cloud of points. The approximation is demonstrated on three 2D examples. Moreover, the formulation of a minimum thickness constraint is applied to a sensitivity-based shape optimization problem of one 2D and one 3D model.

North American sturgeon otolith morphology

USGS Publications Warehouse

Chalupnicki, Marc A.; Dittman, Dawn E.

2016-01-01

Accurate expedient species identification of deceased sturgeon (Acipenseridae) when external physical characteristic analysis is inconclusive has become a high priority due to the endangered or threatened status of sturgeon species around the world. Examination of otoliths has provided useful information to aid in population management, age and size-class analysis, understanding predator–prey interactions, and archeological research in other fish species. The relationship between otolith characteristics and sturgeon species has remained unknown. Therefore, we analyzed the shape of otoliths from the eight species of sturgeon found in North America to test the utility of otolith characteristic morphology in species identification. There were distinct differences in the size and shape of the otoliths between species of sturgeon with little shape variation among individuals of the same species. The relationship between otolith length axes was linear, and most of the variability was explained by a Log (axis + 1) transformation of the x and y axes (r2 = 0.8983) using the equation y = 0.73x + 0.0612. Images of otoliths from all eight North American species are presented to assist in the identification process.

Pulsed field probe of real time magnetization dynamics in magnetic nanoparticle systems

NASA Astrophysics Data System (ADS)

Foulkes, T.; Syed, M.; Taplin, T.

2015-05-01

Magnetic nanoparticles (MNPs) are extensively used in biotechnology. These applications rely on magnetic properties that are a keen function of MNP size, distribution, and shape. Various magneto-optical techniques, including Faraday Rotation (FR), Cotton-Mouton Effect, etc., have been employed to characterize magnetic properties of MNPs. Generally, these measurements employ AC or DC fields. In this work, we describe the results from a FR setup that uses pulsed magnetic fields and an analysis technique that makes use of the entire pulse shape to investigate size distribution and shape anisotropy. The setup employs a light source, polarizing components, and a detector that are used to measure the rotation of light from a sample that is subjected to a pulsed magnetic field. This magnetic field "snapshot" is recorded alongside the intensity pulse of the sample's response. This side by side comparison yields useful information about the real time magnetization dynamics of the system being probed. The setup is highly flexible with variable control of pulse length and peak magnitude. Examining the raw data for the response of bare Fe3O4 and hybrid Au and Fe3O4 nanorods reveals interesting information about Brownian relaxation and the hydrodynamic size of these nanorods. This analysis exploits the self-referencing nature of this measurement to highlight the impact of an applied field on creating a field induced transparency for a longitudinal measurement. Possible sources for this behavior include shape anisotropy and field assisted aggregate formation.

Investigating the Variability in Cumulus Cloud Number as a Function of Subdomain Size and Organization using large-domain LES

NASA Astrophysics Data System (ADS)

Neggers, R.

2017-12-01

Recent advances in supercomputing have introduced a "grey zone" in the representation of cumulus convection in general circulation models, in which this process is partially resolved. Cumulus parameterizations need to be made scale-aware and scale-adaptive to be able to conceptually and practically deal with this situation. A potential way forward are schemes formulated in terms of discretized Cloud Size Densities, or CSDs. Advantages include i) the introduction of scale-awareness at the foundation of the scheme, and ii) the possibility to apply size-filtering of parameterized convective transport and clouds. The CSD is a new variable that requires closure; this concerns its shape, its range, but also variability in cloud number that can appear due to i) subsampling effects and ii) organization in a cloud field. The goal of this study is to gain insight by means of sub-domain analyses of various large-domain LES realizations of cumulus cloud populations. For a series of three-dimensional snapshots, each with a different degree of organization, the cloud size distribution is calculated in all subdomains, for a range of subdomain sizes. The standard deviation of the number of clouds of a certain size is found to decrease with the subdomain size, following a powerlaw scaling corresponding to an inverse-linear dependence. Cloud number variability also increases with cloud size; this reflects that subsampling affects the largest clouds first, due to their typically larger neighbor spacing. Rewriting this dependence in terms of two dimensionless groups, by dividing by cloud number and cloud size respectively, yields a data collapse. Organization in the cloud field is found to act on top of this primary dependence, by enhancing the cloud number variability at the smaller sizes. This behavior reflects that small clouds start to "live" on top of larger structures such as cold pools, favoring or inhibiting their formation (as illustrated by the attached figure of cloud mask). Powerlaw scaling is still evident, but with a reduced exponent, suggesting that this behavior could be parameterized.

The stabilized, wavelet-Mellin transform for analyzing the size and shape information of vocalized sounds

NASA Astrophysics Data System (ADS)

Irino, Toshio; Patterson, Roy

2005-04-01

We hear vowels produced by men, women, and children as approximately the same although there is considerable variability in glottal pulse rate and vocal tract length. At the same time, we can identify the speaker group. Recent experiments show that it is possible to identify vowels even when the glottal pulse rate and vocal tract length are condensed or expanded beyond the range of natural vocalization. This suggests that the auditory system has an automatic process to segregate information about shape and size of the vocal tract. Recently we proposed that the auditory system uses some form of Stabilized, Wavelet-Mellin Transform (SWMT) to analyze scale information in bio-acoustic sounds as a general framework for auditory processing from cochlea to cortex. This talk explains the theoretical background of the model and how the vocal information is normalized in the representation. [Work supported by GASR(B)(2) No. 15300061, JSPS.

Configuration-shape-size optimization of space structures by material redistribution

NASA Technical Reports Server (NTRS)

Vandenbelt, D. N.; Crivelli, L. A.; Felippa, C. A.

1993-01-01

This project investigates the configuration-shape-size optimization (CSSO) of orbiting and planetary space structures. The project embodies three phases. In the first one the material-removal CSSO method introduced by Kikuchi and Bendsoe (KB) is further developed to gain understanding of finite element homogenization techniques as well as associated constrained optimization algorithms that must carry along a very large number (thousands) of design variables. In the CSSO-KB method an optimal structure is 'carved out' of a design domain initially filled with finite elements, by allowing perforations (microholes) to develop, grow and merge. The second phase involves 'materialization' of space structures from the void, thus reversing the carving process. The third phase involves analysis of these structures for construction and operational constraints, with emphasis in packaging and deployment. The present paper describes progress in selected areas of the first project phase and the start of the second one.

Aesthetic breast shape preferences among plastic surgeons.

PubMed

Broer, Peter Niclas; Juran, Sabrina; Walker, Marc E; Ng, Reuben; Weichman, Katie; Tanna, Neil; Liu, Yuen-Jong; Shah, Ajul; Patel, Anup; Persing, John A; Thomson, James Grant

2015-06-01

There has been little discussion in the plastic surgery literature regarding breast shape preferences among plastic surgeons, despite strong evidence that such aesthetic preferences are influenced by multiple factors. Much effort has been focused on delineating the objective criteria by which an "attractive" breast might be defined. This study aimed at providing a better understanding of the presence and significance of differences in personal aesthetic perception, and how these relate to a plastic surgeon's demographic, ethnic, and cultural background, as well as practice type (academic vs private). An interactive online survey was designed. Modifiable ranges of upper pole fullness and areola size were achieved via digital alteration, enabling participants to interactively change the shape of a model's breasts. The questionnaire was translated into multiple languages and sent to plastic surgeons worldwide. Demographic data were also collected. Analysis of variance was used to elucidate plastic surgeon's breast shape preferences in respect to sex and age, geographic and ethnic background, as well as practice type. The authors gathered 614 responses from 29 different countries. Significant differences regarding preferences for upper pole fullness, areola size in the natural breast, and areola size in the augmented breast were identified across surgeons from the different countries. Further, significant relationships regarding breast shape preferences were distilled between the age and sex of the surgeon, as well as the practice type. No differences were found in respect to the surgeons' self-reported ethnic background. Country of residence, age, and practice type significantly impact breast shape preferences of plastic surgeons. These findings have implications for both patients seeking and surgeons performing cosmetic and reconstructive breast surgery. In an increasingly global environment, cultural differences and international variability must be considered when defining and publishing new techniques and aesthetic outcomes. When both the plastic surgeon and the patient are able to adequately and effectively communicate their preferences regarding the shape and relations of the breast, they will be more successful at achieving satisfying results.

Beyond body size: muscle biochemistry and body shape explain ontogenetic variation of anti-predatory behaviour in the lizard Salvator merianae.

PubMed

de Barros, Fábio Cury; de Carvalho, José Eduardo; Abe, Augusto Shinya; Kohlsdorf, Tiana

2016-06-01

Anti-predatory behaviour evolves under the strong action of natural selection because the success of individuals avoiding predation essentially defines their fitness. Choice of anti-predatory strategies is defined by prey characteristics as well as environmental temperature. An additional dimension often relegated in this multilevel equation is the ontogenetic component. In the tegu Salvator merianae, adults run away from predators at high temperatures but prefer fighting when it is cold, whereas juveniles exhibit the same flight strategy within a wide thermal range. Here, we integrate physiology and morphology to understand ontogenetic variation in the temperature-dependent shift of anti-predatory behaviour in these lizards. We compiled data for body shape and size, and quantified enzyme activity in hindlimb and head muscles, testing the hypothesis that morphophysiological models explain ontogenetic variation in behavioural associations. Our prediction is that juveniles exhibit body shape and muscle biochemistry that enhance flight strategies. We identified biochemical differences between muscles mainly in the LDH:CS ratio, whereby hindlimb muscles were more glycolytic than the jaw musculature. Juveniles, which often use evasive strategies to avoid predation, have more glycolytic hindlimb muscles and are much smaller when compared with adults 1-2 years old. Ontogenetic differences in body shape were identified but marginally contributed to behavioural variation between juvenile and adult tegus, and variation in anti-predatory behaviour in these lizards resides mainly in associations between body size and muscle biochemistry. Our results are discussed in the ecological context of predator avoidance by individuals differing in body size living at temperature-variable environments, where restrictions imposed by the cold could be compensated by specific phenotypes. © 2016. Published by The Company of Biologists Ltd.

Evidence of selection on phenotypic plasticity and cost of plasticity in response to host-feeding sources in the major Chagas disease vector Triatoma infestans.

PubMed

Nattero, Julieta; Leonhard, Gustavo; Gürtler, Ricardo E; Crocco, Liliana B

2015-12-01

Phenotypic plasticity is the ability of a genotype to display alternative phenotypes in different environments. Understanding how plasticity evolves and the factors that favor and constrain its evolution have attracted great interest. We investigated whether selection on phenotypic plasticity and costs of plasticity affect head and wing morphology in response to host-feeding sources in the major Chagas disease vector Triatoma infestans. Full-sib families were assigned to blood-feeding on either live pigeons or guinea pigs throughout their lives. We measured diet-induced phenotypic plasticity on wing and head size and shape; characterized selection on phenotypic plasticity for female and male fecundity rates, and evaluated costs of plasticity. Wing size and shape variables exhibited significant differences in phenotypic plasticity associated with host-feeding source in female and male bugs. Evidence of selection on phenotypic plasticity was detected in head size and shape for guinea pig-fed females. A lower female fecundity rate was detected in more plastic families for traits that showed selection on plasticity. These results provide insights into the morphological phenotypic plasticity of T. infestans, documenting fitness advantages of head size and shape for females fed on guinea pigs. This vector species showed measurable benefits of responding plastically to environmental variation rather than adopting a fixed development plan. The presence of cost of plasticity suggests constraints on the evolution of plasticity. Our study indicates that females fed on guinea pigs (and perhaps on other suitable mammalian hosts) have greater chances of evolving under selection on phenotypic plasticity subject to some constraints. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of different spectral shape parameterizations of cloud droplet size distribution on first and second aerosol indirect effects in NACR CAM5 and evaluation with satellite data

NASA Astrophysics Data System (ADS)

Wang, M.; Peng, Y.; Xie, X.; Liu, Y.

2017-12-01

Aerosol cloud interaction continues to constitute one of the most significant uncertainties for anthropogenic climate perturbations. The parameterization of cloud droplet size distribution and autoconversion process from large scale cloud to rain can influence the estimation of first and second aerosol indirect effects in global climate models. We design a series of experiments focusing on the microphysical cloud scheme of NCAR CAM5 (Community Atmospheric Model Version 5) in transient historical run with realistic sea surface temperature and sea ice. We investigate the effect of three empirical, two semi-empirical and one analytical expressions for droplet size distribution on cloud properties and explore the statistical relationships between aerosol optical thickness (AOT) and simulated cloud variables, including cloud top droplet effective radius (CDER), cloud optical depth (COD), cloud water path (CWP). We also introduce the droplet spectral shape parameter into the autoconversion process to incorporate the effect of droplet size distribution on second aerosol indirect effect. Three satellite datasets (MODIS Terra/ MODIS Aqua/ AVHRR) are used to evaluate the simulated aerosol indirect effect from the model. Evident CDER decreasing with significant AOT increasing is found in the east coast of China to the North Pacific Ocean and the east coast of USA to the North Atlantic Ocean. Analytical and semi-empirical expressions for spectral shape parameterization show stronger first aerosol indirect effect but weaker second aerosol indirect effect than empirical expressions because of the narrower droplet size distribution.

Protection of obstetric dimensions in a small-bodied human sample.

PubMed

Kurki, Helen K

2007-08-01

In human females, the bony pelvis must find a balance between being small (narrow) for efficient bipedal locomotion, and being large to accommodate a relatively large newborn. It has been shown that within a given population, taller/larger-bodied women have larger pelvic canals. This study investigates whether in a population where small body size is the norm, pelvic geometry (size and shape), on average, shows accommodation to protect the obstetric canal. Osteometric data were collected from the pelves, femora, and clavicles (body size indicators) of adult skeletons representing a range of adult body size. Samples include Holocene Later Stone Age (LSA) foragers from southern Africa (n = 28 females, 31 males), Portuguese from the Coimbra-identified skeletal collection (CISC) (n = 40 females, 40 males) and European-Americans from the Hamann-Todd osteological collection (H-T) (n = 40 females, 40 males). Patterns of sexual dimorphism are similar in the samples. Univariate and multivariate analyses of raw and Mosimann shape-variables indicate that compared to the CISC and H-T females, the LSA females have relatively large midplane and outlet canal planes (particularly posterior and A-P lengths). The LSA males also follow this pattern, although with absolutely smaller pelves in multivariate space. The CISC females, who have equally small stature, but larger body mass, do not show the same type of pelvic canal size and shape accommodation. The results suggest that adaptive allometric modeling in at least some small-bodied populations protects the obstetric canal. These findings support the use of population-specific attributes in the clinical evaluation of obstetric risk. (c) 2007 Wiley-Liss, Inc.

Theory for computing the size and shape of a region of influence associated with a maneuvering vehicle

NASA Technical Reports Server (NTRS)

Barger, R. L.

1980-01-01

A general procedure for computing the region of influence of a maneuvering vehicle is described. Basic differential geometric relations, including the use of a general trajectory parameter and the introduction of auxiliary variables in the envelope theory are presented. To illustrate the application of the method, the destruct region for a maneuvering fighter firing missiles is computed.

[Evaluation of the apron as a taxonomic trait in ixodid ticks of the genus Dermacentor Koch (Ixodoidea, Ixodidae)].

PubMed

Filippova, N A; Panova, I V

1986-01-01

Study of the apron in 9 species of the genus Dermacentor from the fauna of the USSR has revealed differencies in its structure. The subgenus Dermacentor (s. str.) differs from two other subgenera both in the shape of the apron itself and in the shape of the postgenital sclerite and setae of perigenital area. Close species within each of two other subgenera differ in apron proportion, shape and size of denticles along its hind edge, and sometimes in their number. Inspite of the statistically reliable interspecific differences in apron structure a wide range of individual variability of some details and geographical specificity of samples from various places of the area were observed in species with a vast area.

Introduction to Blueweb: A Decentralized Scatternet Formation Algorithm for Bluetooth Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Yu, Chih-Min; Huang, Chia-Chi

In this letter, a decentralized scatternet formation algorithm called Bluelayer is proposed. First, Bluelayer uses a designated root to construct a tree-shaped subnet and propagates an integer variable k1 called counter limit as well as a constant k in its downstream direction to determine new roots. Then each new root asks its upstream master to start a return connection procedure to convert the tree-shaped subnet into a web-shaped subnet for its immediate upstream root. At the same time, each new root repeats the same procedure as the root to build its own subnet until the whole scatternet is formed. Simulation results show that Bluelayer achieves good network scalability and generates an efficient scatternet configuration for various sizes of Bluetooth ad hoc network.

Statistical shape analysis of clavicular cortical bone with applications to the development of mean and boundary shape models.

PubMed

Lu, Yuan-Chiao; Untaroiu, Costin D

2013-09-01

During car collisions, the shoulder belt exposes the occupant's clavicle to large loading conditions which often leads to a bone fracture. To better understand the geometric variability of clavicular cortical bone which may influence its injury tolerance, twenty human clavicles were evaluated using statistical shape analysis. The interior and exterior clavicular cortical bone surfaces were reconstructed from CT-scan images. Registration between one selected template and the remaining 19 clavicle models was conducted to remove translation and rotation differences. The correspondences of landmarks between the models were then established using coordinates and surface normals. Three registration methods were compared: the LM-ICP method; the global method; and the SHREC method. The LM-ICP registration method showed better performance than the global and SHREC registration methods, in terms of compactness, generalization, and specificity. The first four principal components obtained by using the LM-ICP registration method account for 61% and 67% of the overall anatomical variation for the exterior and interior cortical bone shapes, respectively. The length was found to be the most significant variation mode of the human clavicle. The mean and two boundary shape models were created using the four most significant principal components to investigate the size and shape variation of clavicular cortical bone. In the future, boundary shape models could be used to develop probabilistic finite element models which may help to better understand the variability in biomechanical responses and injuries to the clavicle. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Wing Shape as an Indicator of Larval Rearing Conditions for Aedes albopictus and Ae. aegypti (Diptera: Culicidae)

PubMed Central

Stephens, C. R.; Juliano, S. A.

2012-01-01

Estimating a mosquito’s vector competence, or likelihood of transmitting disease, if it takes an infectious blood meal, is an important aspect of predicting when and where outbreaks of infectious diseases will occur. Vector competence can be affected by rearing temperature and inter- and intraspecific competition experienced by the individual mosquito during its larval development. This research investigates whether a new morphological indicator of larval rearing conditions, wing shape, can be used to distinguish reliably temperature and competitive conditions experienced during larval stages. Aedes albopictus and Aedes aegypti larvae were reared in low intra-specific, high intra-specific, or high inter-specific competition treatments at either 22°C or 32°C. The right wing of each dried female was removed and photographed. Nineteen landmarks and twenty semilandmarks were digitized on each wing. Shape variables were calculated using geometric morphometric software. Canonical variate analysis, randomization multivariate analysis of variance, and visualization of landmark movement using deformation grids provided evidence that although semilandmark position was significantly affected by larval competition and temperature for both species, the differences in position did not translate into differences in wing shape, as shown in deformation grids. Two classification procedures yielded success rates of 26–49%. Accounting for wing size produced no increase in classification success. There appeared to be a significant relationship between shape and size. These results, particularly the low success rate of classification based on wing shape, show that shape is unlikely to be a reliable indicator of larval rearing competition and temperature conditions for Aedes albopictus and Aedes aegypti. PMID:22897054

The effect of environmental uncertainty on morphological design and fluid balance in Sarracenia purpurea L.

PubMed

Kingsolver, Joel

1981-03-01

To explore principles of organismic design in fluctuating environments, morphological design of the leaf of the pitcher-plant, Sarracenia purpurea, was studied for a population in northern Michigan. The design criterion focused upon the leaf shape and minimum size which effectively avoids leaf desiccation (complete loss of fluid from the leaf cavity) in the face of fluctuating rainfall and meteorological conditions. Bowl- and pitcher-shaped leaves were considered. Simulations show that the pitcher geometry experiences less frequent desiccation than bowls of the same size. Desiccation frequency is inversely related to leaf size; the size distribution of pitcher leaves in the field shows that the majority of pitchers desiccate only 1-3 times per season on average, while smaller pitchers may average up to 8 times per season. A linear filter model of an organism in a fluctuating environment is presented, in which the organism selectively filters the temporal patterns of environmental input. General measures of rainfall predictability based upon information theory and spectral analysis are consistent with the model of a pitcher leaf as a low-pass (frequency) filter which avoids desiccation by eliminating high-frequency rainfall variability.

Size and shape in Melipona quadrifasciata anthidioides Lepeletier, 1836 (Hymenoptera; Meliponini).

PubMed

Nunes, L A; Passos, G B; Carvalho, C A L; Araújo, E D

2013-11-01

This study aimed to identify differences in wing shape among populations of Melipona quadrifasciata anthidioides obtained in 23 locations in the semi-arid region of Bahia state (Brazil). Analysis of the Procrustes distances among mean wing shapes indicated that population structure did not determine shape variation. Instead, populations were structured geographically according to wing size. The Partial Mantel Test between morphometric (shape and size) distance matrices and altitude, taking geographic distances into account, was used for a more detailed understanding of size and shape determinants. A partial Mantel test between morphometris (shape and size) variation and altitude, taking geographic distances into account, revealed that size (but not shape) is largely influenced by altitude (r = 0.54 p < 0.01). These results indicate greater evolutionary constraints for the shape variation, which must be directly associated with aerodynamic issues in this structure. The size, however, indicates that the bees tend to have larger wings in populations located at higher altitudes.

Leaf Morphology, Taxonomy and Geometric Morphometrics: A Simplified Protocol for Beginners

PubMed Central

Viscosi, Vincenzo; Cardini, Andrea

2011-01-01

Taxonomy relies greatly on morphology to discriminate groups. Computerized geometric morphometric methods for quantitative shape analysis measure, test and visualize differences in form in a highly effective, reproducible, accurate and statistically powerful way. Plant leaves are commonly used in taxonomic analyses and are particularly suitable to landmark based geometric morphometrics. However, botanists do not yet seem to have taken advantage of this set of methods in their studies as much as zoologists have done. Using free software and an example dataset from two geographical populations of sessile oak leaves, we describe in detailed but simple terms how to: a) compute size and shape variables using Procrustes methods; b) test measurement error and the main levels of variation (population and trees) using a hierachical design; c) estimate the accuracy of group discrimination; d) repeat this estimate after controlling for the effect of size differences on shape (i.e., allometry). Measurement error was completely negligible; individual variation in leaf morphology was large and differences between trees were generally bigger than within trees; differences between the two geographic populations were small in both size and shape; despite a weak allometric trend, controlling for the effect of size on shape slighly increased discrimination accuracy. Procrustes based methods for the analysis of landmarks were highly efficient in measuring the hierarchical structure of differences in leaves and in revealing very small-scale variation. In taxonomy and many other fields of botany and biology, the application of geometric morphometrics contributes to increase scientific rigour in the description of important aspects of the phenotypic dimension of biodiversity. Easy to follow but detailed step by step example studies can promote a more extensive use of these numerical methods, as they provide an introduction to the discipline which, for many biologists, is less intimidating than the often inaccessible specialistic literature. PMID:21991324

Moderate climate signature in cranial anatomy of late holocene human populations from Southern South America.

PubMed

Paula Menéndez, Lumila

2018-02-01

The aim of this study is to analyze the association between cranial variation and climate in order to discuss their role during the diversification of southern South American populations. Therefore, the specific objectives are: (1) to explore the spatial pattern of cranial variation with regard to the climatic diversity of the region, and (2) to evaluate the differential impact that the climatic factors may have had on the shape and size of the diverse cranial structures studied. The variation in shape and size of 361 crania was studied, registering 62 3D landmarks that capture shape and size variation in the face, cranial vault, and base. Mean, minimum, and maximum annual temperature, as well as mean annual precipitation, but also diet and altitude, were matched for each population sample. A PCA, as well as spatial statistical techniques, including kriging, regression, and multimodel inference were employed. The facial skeleton size presents a latitudinal pattern which is partially associated with temperature diversity. Both diet and altitude are the variables that mainly explain the skull shape variation, although mean annual temperature also plays a role. The association between climate factors and cranial variation is low to moderate, mean annual temperature explains almost 40% of the entire skull, facial skeleton and cranial vault shape variation, while annual precipitation and minimum annual temperature only contribute to the morphological variation when considered together with maximum annual temperature. The cranial base is the structure less associated with climate diversity. These results suggest that climate factors may have had a partial impact on the facial and vault shape, and therefore contributed moderately to the diversification of southern South American populations, while diet and altitude might have had a stronger impact. Therefore, cranial variation at the southern cone has been shaped both by random and nonrandom factors. Particularly, the influence of climate on skull shape has probably been the result of directional selection. This study supports that, although cranial vault is the cranial structure more associated to mean annual temperature, the impact of climate signature on morphology decreases when populations from extreme cold environments are excluded from the analysis. Additionally, it shows that the extent of the geographical scales analyzed, as well as differential sampling may lead to different results regarding the role of ecological factors and evolutionary processes on cranial morphology. © 2017 Wiley Periodicals, Inc.

The Hot-Pressing of Hafnium Carbide (Melting Point, 7030 F)

NASA Technical Reports Server (NTRS)

Sanders, William A.; Grisaffe, Salvatore J.

1960-01-01

An investigation was undertaken to determine the effects of the hot-pressing variables (temperature, pressure, and time) on the density and grain size of hafnium carbide disks. The purpose was to provide information necessary for the production of high-density test shapes for the determination of physical and mechanical properties. Hot-pressing of -325 mesh hafnium carbide powder was accomplished with a hydraulic press and an inductively heated graphite die assembly. The ranges investigated for each variable were as follows: temperature, 3500 to 4870 F; pressure, 1000 to 6030 pounds per square inch; and time, 5 to 60 minutes. Hafnium carbide bodies of approximately 98 percent theoretical density can be produced under the following minimal conditions: 4230 F, 3500 pounds per square inch, and 15 minutes. Further increases in temperature and time resulted only in greater grain size.

Variable aperture-based ptychographical iterative engine method

NASA Astrophysics Data System (ADS)

Sun, Aihui; Kong, Yan; Meng, Xin; He, Xiaoliang; Du, Ruijun; Jiang, Zhilong; Liu, Fei; Xue, Liang; Wang, Shouyu; Liu, Cheng

2018-02-01

A variable aperture-based ptychographical iterative engine (vaPIE) is demonstrated both numerically and experimentally to reconstruct the sample phase and amplitude rapidly. By adjusting the size of a tiny aperture under the illumination of a parallel light beam to change the illumination on the sample step by step and recording the corresponding diffraction patterns sequentially, both the sample phase and amplitude can be faithfully reconstructed with a modified ptychographical iterative engine (PIE) algorithm. Since many fewer diffraction patterns are required than in common PIE and the shape, the size, and the position of the aperture need not to be known exactly, this proposed vaPIE method remarkably reduces the data acquisition time and makes PIE less dependent on the mechanical accuracy of the translation stage; therefore, the proposed technique can be potentially applied for various scientific researches.

Investigation of the effect of tablet surface area/volume on drug release from hydroxypropylmethylcellulose controlled-release matrix tablets.

PubMed

Reynolds, Thomas D; Mitchell, Shawn A; Balwinski, Karen M

2002-04-01

The purpose of this study was to investigate the influence of tablet surface area/volume (SA/Vol) on drug release from controlled-release matrix tablets containing hydroxypropylmethylcellulose (HPMC). Soluble drugs (promethazine HCl, diphenhydramine HCl, and propranolol HCl) were utilized in this study to give predominantly diffusion-controlled release. Drug release from HPMC matrix tablets with similar values of SA/Vol was comparable within the same tablet shape (i.e., flat-faced round tablets) and among different shapes (i.e., oval, round concave, flat-faced beveled-edge, and flat-faced round tablets). Tablets having the same surface area but different SA/Vol values did not result in similar drug release; tablets with larger SA/Vol values hadfaster release profiles. Utility of SA/Vol to affect drug release was demonstrated by changing drug doses, and altering tablet shape to adjust SA/Vol. When SA/Vol was held constant, similar release profiles were obtained with f2 metric values greater than 70. Thus, surface area/volume is one of the key variables in controlling drug release from HPMC matrix tablets. Proper use of this variable has practical application by formulators who may need to duplicate drug release profiles from tablets of different sizes and different shapes.

Influence of size, shape, and flexibility on bacterial passage through micropore membrane filters.

PubMed

Wang, Yingying; Hammes, Frederik; Düggelin, Marcel; Egli, Thomas

2008-09-01

Sterilization of fluids by means of microfiltration is commonly applied in research laboratories as well as in pharmaceutical and industrial processes. Sterile micropore filters are subject to microbiological validation, where Brevundimonas diminuta is used as a standard test organism. However, several recent reports on the ubiquitous presence of filterable bacteria in aquatic environments have cast doubt on the accuracy and validity of the standard filter-testing method. Six different bacterial species of various sizes and shapes (Hylemonella gracilis, Escherichia coli, Sphingopyxis alaskensis, Vibrio cholerae, Legionella pneumophila, and B. diminuta) were tested for their filterability through sterile micropore filters. In all cases, the slender spirillum-shaped Hylemonella gracilis cells showed a superior ability to pass through sterile membrane filters. Our results provide solid evidence that the overall shape (including flexibility), instead of biovolume, is the determining factor for the filterability of bacteria, whereas cultivation conditions also play a crucial role. Furthermore, the filtration volume has a more important effect on the passage percentage in comparison with other technical variables tested (including flux and filter material). Based on our findings, we recommend a re-evaluation of the grading system for sterile filters, and suggest that the species Hylemonella should be considered as an alternative filter-testing organism for the quality assessment of micropore filters.

Head-and-face shape variations of U.S. civilian workers

PubMed Central

Zhuang, Ziqing; Shu, Chang; Xi, Pengcheng; Bergman, Michael; Joseph, Michael

2016-01-01

The objective of this study was to quantify head-and-face shape variations of U.S. civilian workers using modern methods of shape analysis. The purpose of this study was based on previously highlighted changes in U.S. civilian worker head-and-face shape over the last few decades – touting the need for new and better fitting respirators – as well as the study's usefulness in designing more effective personal protective equipment (PPE) – specifically in the field of respirator design. The raw scan three-dimensional (3D) data for 1169 subjects were parameterized using geometry processing techniques. This process allowed the individual scans to be put in correspondence with each other in such a way that statistical shape analysis could be performed on a dense set of 3D points. This process also cleaned up the original scan data such that the noise was reduced and holes were filled in. The next step, statistical analysis of the variability of the head-and-face shape in the 3D database, was conducted using Principal Component Analysis (PCA) techniques. Through these analyses, it was shown that the space of the head-and-face shape was spanned by a small number of basis vectors. Less than 50 components explained more than 90% of the variability. Furthermore, the main mode of variations could be visualized through animating the shape changes along the PCA axes with computer software in executable form for Windows XP. The results from this study in turn could feed back into respirator design to achieve safer, more efficient product style and sizing. Future study is needed to determine the overall utility of the point cloud-based approach for the quantification of facial morphology variation and its relationship to respirator performance. PMID:23399025

Head-and-face shape variations of U.S. civilian workers.

PubMed

Zhuang, Ziqing; Shu, Chang; Xi, Pengcheng; Bergman, Michael; Joseph, Michael

2013-09-01

The objective of this study was to quantify head-and-face shape variations of U.S. civilian workers using modern methods of shape analysis. The purpose of this study was based on previously highlighted changes in U.S. civilian worker head-and-face shape over the last few decades - touting the need for new and better fitting respirators - as well as the study's usefulness in designing more effective personal protective equipment (PPE) - specifically in the field of respirator design. The raw scan three-dimensional (3D) data for 1169 subjects were parameterized using geometry processing techniques. This process allowed the individual scans to be put in correspondence with each other in such a way that statistical shape analysis could be performed on a dense set of 3D points. This process also cleaned up the original scan data such that the noise was reduced and holes were filled in. The next step, statistical analysis of the variability of the head-and-face shape in the 3D database, was conducted using Principal Component Analysis (PCA) techniques. Through these analyses, it was shown that the space of the head-and-face shape was spanned by a small number of basis vectors. Less than 50 components explained more than 90% of the variability. Furthermore, the main mode of variations could be visualized through animating the shape changes along the PCA axes with computer software in executable form for Windows XP. The results from this study in turn could feed back into respirator design to achieve safer, more efficient product style and sizing. Future study is needed to determine the overall utility of the point cloud-based approach for the quantification of facial morphology variation and its relationship to respirator performance. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

A simple technique of laparoscopic port closure allowing wound extension.

PubMed

Christey, G R; Poole, G

2002-04-01

Reliable and safe access to the abdominal cavity and efficient removal of the resected gallbladder are essential to laparoscopic cholecystectomy. The unpredictable size of the cholecystectomy specimen can sometimes lead to frustration at the time of removal. A simple technique has been developed that allows for tissue extraction and easy fascial closure regardless of the size of the specimen. This is achieved by using a four bite "U-shaped" purse string at the time of Hasson insertion, with cephalad advancement of the proximal two bites. This allows for variable wound extension and secure closure, without the need for additional sutures.

Differentiating gold nanorod samples using particle size and shape distributions from transmission electron microscope images

NASA Astrophysics Data System (ADS)

Grulke, Eric A.; Wu, Xiaochun; Ji, Yinglu; Buhr, Egbert; Yamamoto, Kazuhiro; Song, Nam Woong; Stefaniak, Aleksandr B.; Schwegler-Berry, Diane; Burchett, Woodrow W.; Lambert, Joshua; Stromberg, Arnold J.

2018-04-01

Size and shape distributions of gold nanorod samples are critical to their physico-chemical properties, especially their longitudinal surface plasmon resonance. This interlaboratory comparison study developed methods for measuring and evaluating size and shape distributions for gold nanorod samples using transmission electron microscopy (TEM) images. The objective was to determine whether two different samples, which had different performance attributes in their application, were different with respect to their size and/or shape descriptor distributions. Touching particles in the captured images were identified using a ruggedness shape descriptor. Nanorods could be distinguished from nanocubes using an elongational shape descriptor. A non-parametric statistical test showed that cumulative distributions of an elongational shape descriptor, that is, the aspect ratio, were statistically different between the two samples for all laboratories. While the scale parameters of size and shape distributions were similar for both samples, the width parameters of size and shape distributions were statistically different. This protocol fulfills an important need for a standardized approach to measure gold nanorod size and shape distributions for applications in which quantitative measurements and comparisons are important. Furthermore, the validated protocol workflow can be automated, thus providing consistent and rapid measurements of nanorod size and shape distributions for researchers, regulatory agencies, and industry.

Surface nucleation in complex rheological systems

NASA Astrophysics Data System (ADS)

Herfurth, J.; Ulrich, J.

2017-07-01

Forced nucleation induced by suitable foreign seeds is an important tool to control the production of defined crystalline products. The quality of a surface provided by seed materials represents an important variable in the production of crystallizing layers that means for the nucleation process. Parameters like shape and surface structure, size and size distribution of the seed particles as well as the ability to hold up the moisture (the solvent), can have an influence on the nucleation process of different viscous supersaturated solutions. Here the properties of different starch powders as seeds obtained from corn, potato, rice, tapioca and wheat were tested. It could be found, that the best nucleation behavior of a sugar solution could be reached with the use of corn starch as seed material. Here the surface of the crystallized sugar layer is smooth, crystallization time is short (<3 h) and the shape of the product is easily reproducible. Beneficial properties of seed materials are therefore an edged, uneven surface, small particle sizes as well as low moisture content at ambient conditions within the seed materials.

Do size, shape, and alignment parameters of the femoral condyle affect the trochlear groove tracking? A morphometric study based on 3D- computed tomography models in Chinese people.

PubMed

Du, Zhe; Chen, Shichang; Yan, Mengning; Yue, Bing; Zeng, Yiming; Wang, You

2017-01-06

Our study aimed to investigate whether geometrical features (size, shape, or alignment parameters) of the femoral condyle affect the morphology of the trochlear groove. Computed tomography models of 195 femurs (97 and 98 knees from male and female subjects, respectively) were reconstructed into three-dimensional models and categorised into four types of trochlear groove morphology based on the position of the turning point in relation to the mechanical axis (types 45°, 60°, 75°, and 90°). Only subjects with healthy knees were included, whereas individuals with previous knee trauma or knee pain, soft tissue injury, osteoarthritis, or other chronic diseases of the musculoskeletal system were excluded. The size parameters were: radius of the best-fit cylinder, anteroposterior dimension of the lateral condyles (AP), and distal mediolateral dimension (ML). The shape parameters were: aspect ratio (AP/ML), arc angle, and proximal- and distal- end angles. The alignment parameters were: knee valgus physiologic angle (KVPA), mechanical medial distal femoral angle (mMDFA), and hip-knee-ankle angle (HKA). All variables were measured in the femoral condyle models, and the means for each groove type were compared using one-way analysis of variance. No significant difference among groove types was observed regarding size parameters. There were significant differences when comparing type 45° with types 60°, 75°, and 90° regarding aspect ratio and distal-end angle (p < 0.05), but not regarding proximal-end angle. There were significant differences when comparing type 90° with types 45°, 60°, and 75° regarding KVPA, mMDFA, and HKA (p < 0.05). Among size, shape, and alignment parameters, the latter two exhibited partial influence on the morphology of the trochlear groove. Shape parameters affected the trochlear groove for trochlear type 45°, for which the femoral condyle was relatively flat, whereas alignment parameters affected the trochlear groove for trochlear type 90°, showing that knees in type 90° tend to be valgus. The morphometric analysis based on trochlear groove classification may be helpful for the future design of individualized prostheses.

SU-F-T-577: Comparison of Small Field Dosimetry Measurements in Fields Shaped with Conical Applicators On Two Different Accelerating Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, B; McEwen, M; Belec, J

2016-06-15

Purpose: To investigate small field dosimetry measurements and associated uncertainties when conical applicators are used to shape treatment fields from two different accelerating systems. Methods: Output factor measurements are made in water in beams from the CyberKnife radiosurgery system, which uses conical applicators to shape fields from a (flattening filter-free) 6 MV beam, and in a 6 MV beam from the Elekta Precise linear accelerator (with flattening filter) with BrainLab external conical applicators fitted to shape the field. The measurements use various detectors: (i) an Exradin A16 ion chamber, (ii) two Exradin W1 plastic scintillation detectors, (iii) a Sun Nuclearmore » Edge diode, and (iv) two PTW microDiamond synthetic diamond detectors. Profiles are used for accurate detector positioning and to specify field size (FWHM). Output factor measurements are corrected with detector specific correction factors taken from the literature where available and/or from Monte Carlo simulations using the EGSnrc code system. Results: Differences in measurements of up to 1.7% are observed with a given detector type in the same beam (i.e., intra-detector variability). Corrected results from different detectors in the same beam (inter-detector differences) show deviations up to 3 %. Combining data for all detectors and comparing results from the two accelerators results in a 5.9% maximum difference for the smallest field sizes (FWHM=5.2–5.6 mm), well outside the combined uncertainties (∼1% for the smallest beams) and/or differences among detectors. This suggests that the FWHM of a measured profile is not a good specifier to compare results from different small fields with the same nominal energy. Conclusion: Large differences in results for both intra-detector variability and inter-detector differences suggest potentially high uncertainties in detector-specific correction factors. Differences between the results measured in circular fields from different accelerating systems provide insight into sources of variability in small field dosimetric measurements reported in the literature.« less

78 FR 74154 - Draft Guidance for Industry on Size, Shape, and Other Physical Attributes of Generic Tablets and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-10

...] Draft Guidance for Industry on Size, Shape, and Other Physical Attributes of Generic Tablets and... ``Size, Shape, and Other Physical Attributes of Generic Tablets and Capsules.'' This guidance discusses FDA recommendations for the size, shape, and other physical attributes of generic tablets intended to...

Bioavailability of Lead in Small Arms Range Soils

DTIC Science & Technology

2009-08-01

titanium TOC total organic carbon USEPA U.S. Environmental Protection Agency XRF X-ray fluorescence Zn zinc Zr zirconium 1 1.0 EXECUTIVE...particles of inert matrix such as rock or slag of variable size, shape, and association; these chemical and physical properties may influence the absorption...zirconium, Pb=lead, Cu=copper, Mn=manganese, Si=silicon, Zn= zinc , As=arsenic, Cd=cadmium, CEC= cation exchange capacity, TOC = total organic carbon, Sb

Piezoelectric Nanogenerators for Self-Powered Nanosystems and Nanosensors

DTIC Science & Technology

2013-05-15

mechanical triggering applied onto the nanogenerator. The structure and general working principle of the spring-substrated nanogenerator ( SNG ) are...schematically shown in Fig. 3a–c. Compressive springs with variable sizes were selected as the skeletons of the SNG devices. The helix-shaped spring surface...In the measurement for the output performance of the SNG , one end of the spring was fixed onto a three-dimensional stage; meanwhile a mechanical

Three-dimensional quantitative analysis of healthy foot shape: a proof of concept study.

PubMed

Stanković, Kristina; Booth, Brian G; Danckaers, Femke; Burg, Fien; Vermaelen, Philippe; Duerinck, Saartje; Sijbers, Jan; Huysmans, Toon

2018-01-01

Foot morphology has received increasing attention from both biomechanics researches and footwear manufacturers. Usually, the morphology of the foot is quantified by 2D footprints. However, footprint quantification ignores the foot's vertical dimension and hence, does not allow accurate quantification of complex 3D foot shape. The shape variation of healthy 3D feet in a population of 31 adult women and 31 adult men who live in Belgium was studied using geometric morphometric methods. The effect of different factors such as sex, age, shoe size, frequency of sport activity, Body Mass Index (BMI), foot asymmetry, and foot loading on foot shape was investigated. Correlation between these factors and foot shape was examined using multivariate linear regression. The complex nature of a foot's 3D shape leads to high variability in healthy populations. After normalizing for scale, the major axes of variation in foot morphology are (in order of decreasing variance): arch height, combined ball width and inter-toe distance, global foot width, hallux bone orientation (valgus-varus), foot type (e.g. Egyptian, Greek), and midfoot width. These first six modes of variation capture 92.59% of the total shape variation. Higher BMI results in increased ankle width, Achilles tendon width, heel width and a thicker forefoot along the dorsoplantar axis. Age was found to be associated with heel width, Achilles tendon width, toe height and hallux orientation. A bigger shoe size was found to be associated with a narrow Achilles tendon, a hallux varus, a narrow heel, heel expansion along the posterior direction, and a lower arch compared to smaller shoe size. Sex was found to be associated with differences in ankle width, Achilles tendon width, and heel width. Frequency of sport activity was associated with Achilles tendon width and toe height. A detailed analysis of the 3D foot shape, allowed by geometric morphometrics, provides insights in foot variations in three dimensions that can not be obtained from 2D footprints. These insights could be applied in various scientific disciplines, including orthotics and shoe design.

Gum ghatti mediated, one pot green synthesis of optimized gold nanoparticles: Investigation of process-variables impact using Box-Behnken based statistical design.

PubMed

Alam, Md Sabir; Garg, Arun; Pottoo, Faheem Hyder; Saifullah, Mohammad Khalid; Tareq, Abu Izneid; Manzoor, Ovais; Mohsin, Mohd; Javed, Md Noushad

2017-11-01

Due to unique inherent catalytic characteristics of different size, shape and surface functionalized gold nanoparticles, their potential applications, are being explored in various fields such as drug delivery, biosensor, diagnosis and theranostics. However conventional process for synthesis of these metallic nanoparticles utilizes toxic reagents as reducing agents, additional capping agent for stability as well as surface functionalization for drug delivery purposes. Hence, in this work suitability of gum Ghatti for reducing, capping and surface functionalization during the synthesis of stable Gold nanoparticles were duly explored. Role and impact of key process variables i.e. volume of chloroauric acid solution, gum solution and temperature at their respective three different levels, as well as mechanism of formation of optimized gold nanoparticles were also investigated using Box- Behnken design. These novel synthesized optimized Gold nanoparticles were further characterized by UV spectrophotometer for its surface plasmon resonance (SPR) at around ∼530nm, dynamic light scattering (DLS) for its hydrodynamic size (112.5nm), PDI (0.222) and zeta potential (-21.3mV) while, transmission electron microscopy (TEM) further revealed surface geometry of these nanoparticles being spherical in shape. Copyright © 2017 Elsevier B.V. All rights reserved.

Target identification using Zernike moments and neural networks

NASA Astrophysics Data System (ADS)

Azimi-Sadjadi, Mahmood R.; Jamshidi, Arta A.; Nevis, Andrew J.

2001-10-01

The development of an underwater target identification algorithm capable of identifying various types of underwater targets, such as mines, under different environmental conditions pose many technical problems. Some of the contributing factors are: targets have diverse sizes, shapes and reflectivity properties. Target emplacement environment is variable; targets may be proud or partially buried. Environmental properties vary significantly from one location to another. Bottom features such as sand, rocks, corals, and vegetation can conceal a target whether it is partially buried or proud. Competing clutter with responses that closely resemble those of the targets may lead to false positives. All the problems mentioned above contribute to overly difficult and challenging conditions that could lead to unreliable algorithm performance with existing methods. In this paper, we developed and tested a shape-dependent feature extraction scheme that provides features invariant to rotation, size scaling and translation; properties that are extremely useful for any target classification problem. The developed schemes were tested on an electro-optical imagery data set collected under different environmental conditions with variable background, range and target types. The electro-optic data set was collected using a Laser Line Scan (LLS) sensor by the Coastal Systems Station (CSS), located in Panama City, Florida. The performance of the developed scheme and its robustness to distortion, rotation, scaling and translation was also studied.

Size, shape, and diffusivity of a single Debye-Hückel polyelectrolyte chain in solution.

PubMed

Soysa, W Chamath; Dünweg, B; Prakash, J Ravi

2015-08-14

Brownian dynamics simulations of a coarse-grained bead-spring chain model, with Debye-Hückel electrostatic interactions between the beads, are used to determine the root-mean-square end-to-end vector, the radius of gyration, and various shape functions (defined in terms of eigenvalues of the radius of gyration tensor) of a weakly charged polyelectrolyte chain in solution, in the limit of low polymer concentration. The long-time diffusivity is calculated from the mean square displacement of the centre of mass of the chain, with hydrodynamic interactions taken into account through the incorporation of the Rotne-Prager-Yamakawa tensor. Simulation results are interpreted in the light of the Odjik, Skolnick, Fixman, Khokhlov, and Khachaturian blob scaling theory (Everaers et al., Eur. Phys. J. E 8, 3 (2002)) which predicts that all solution properties are determined by just two scaling variables-the number of electrostatic blobs X and the reduced Debye screening length, Y. We identify three broad regimes, the ideal chain regime at small values of Y, the blob-pole regime at large values of Y, and the crossover regime at intermediate values of Y, within which the mean size, shape, and diffusivity exhibit characteristic behaviours. In particular, when simulation results are recast in terms of blob scaling variables, universal behaviour independent of the choice of bead-spring chain parameters, and the number of blobs X, is observed in the ideal chain regime and in much of the crossover regime, while the existence of logarithmic corrections to scaling in the blob-pole regime leads to non-universal behaviour.

The zipper mechanism in phagocytosis: energetic requirements and variability in phagocytic cup shape

PubMed Central

2010-01-01

Background Phagocytosis is the fundamental cellular process by which eukaryotic cells bind and engulf particles by their cell membrane. Particle engulfment involves particle recognition by cell-surface receptors, signaling and remodeling of the actin cytoskeleton to guide the membrane around the particle in a zipper-like fashion. Despite the signaling complexity, phagocytosis also depends strongly on biophysical parameters, such as particle shape, and the need for actin-driven force generation remains poorly understood. Results Here, we propose a novel, three-dimensional and stochastic biophysical model of phagocytosis, and study the engulfment of particles of various sizes and shapes, including spiral and rod-shaped particles reminiscent of bacteria. Highly curved shapes are not taken up, in line with recent experimental results. Furthermore, we surprisingly find that even without actin-driven force generation, engulfment proceeds in a large regime of parameter values, albeit more slowly and with highly variable phagocytic cups. We experimentally confirm these predictions using fibroblasts, transfected with immunoreceptor FcγRIIa for engulfment of immunoglobulin G-opsonized particles. Specifically, we compare the wild-type receptor with a mutant receptor, unable to signal to the actin cytoskeleton. Based on the reconstruction of phagocytic cups from imaging data, we indeed show that cells are able to engulf small particles even without support from biological actin-driven processes. Conclusions This suggests that biochemical pathways render the evolutionary ancient process of phagocytic highly robust, allowing cells to engulf even very large particles. The particle-shape dependence of phagocytosis makes a systematic investigation of host-pathogen interactions and an efficient design of a vehicle for drug delivery possible. PMID:21059234

Semicircular canals in Anolis lizards: ecomorphological convergence and ecomorph affinities of fossil species.

PubMed

Dickson, Blake V; Sherratt, Emma; Losos, Jonathan B; Pierce, Stephanie E

2017-10-01

Anoli s lizards are a model system for the study of adaptive radiation and convergent evolution. Greater Antillean anoles have repeatedly evolved six similar forms or ecomorphs: crown-giant, grass-bush, twig, trunk, trunk-crown and trunk-ground. Members of each ecomorph category possess a specific set of morphological, ecological and behavioural characteristics which have been acquired convergently. Here we test whether the semicircular canal system-the organ of balance during movement-is also convergent among ecomorphs, reflecting the shared sensory requirements of their ecological niches. As semicircular canal shape has been shown to reflect different locomotor strategies, we hypothesized that each Anolis ecomorph would have a unique canal morphology. Using three-dimensional semilandmarks and geometric morphometrics, semicircular canal shape was characterized in 41 Anolis species from the Greater Antilles and the relationship between canal shape and ecomorph grouping, phylogenetic history, size, head dimensions, and perch characteristics was assessed. Further, canal morphology of modern species was used to predict the ecomorph affinity of five fossil anoles from the Miocene of the Dominican Republic. Of the covariates tested, our study recovered ecomorph as the single-most important covariate of canal morphology in modern taxa; although phylogenetic history, size, and head dimensions also showed a small, yet significant correlation with shape. Surprisingly, perch characteristics were not found to be significant covariates of canal shape, even though they are important habitat variables. Using posterior probabilities, we found that the fossil anoles have different semicircular canals shapes to modern ecomorph groupings implying extinct anoles may have been interacting with their Miocene environment in different ways to modern Anolis species.

Semicircular canals in Anolis lizards: ecomorphological convergence and ecomorph affinities of fossil species

NASA Astrophysics Data System (ADS)

Dickson, Blake V.; Sherratt, Emma; Losos, Jonathan B.; Pierce, Stephanie E.

2017-10-01

Anolis lizards are a model system for the study of adaptive radiation and convergent evolution. Greater Antillean anoles have repeatedly evolved six similar forms or ecomorphs: crown-giant, grass-bush, twig, trunk, trunk-crown and trunk-ground. Members of each ecomorph category possess a specific set of morphological, ecological and behavioural characteristics which have been acquired convergently. Here we test whether the semicircular canal system-the organ of balance during movement-is also convergent among ecomorphs, reflecting the shared sensory requirements of their ecological niches. As semicircular canal shape has been shown to reflect different locomotor strategies, we hypothesized that each Anolis ecomorph would have a unique canal morphology. Using three-dimensional semilandmarks and geometric morphometrics, semicircular canal shape was characterized in 41 Anolis species from the Greater Antilles and the relationship between canal shape and ecomorph grouping, phylogenetic history, size, head dimensions, and perch characteristics was assessed. Further, canal morphology of modern species was used to predict the ecomorph affinity of five fossil anoles from the Miocene of the Dominican Republic. Of the covariates tested, our study recovered ecomorph as the single-most important covariate of canal morphology in modern taxa; although phylogenetic history, size, and head dimensions also showed a small, yet significant correlation with shape. Surprisingly, perch characteristics were not found to be significant covariates of canal shape, even though they are important habitat variables. Using posterior probabilities, we found that the fossil anoles have different semicircular canals shapes to modern ecomorph groupings implying extinct anoles may have been interacting with their Miocene environment in different ways to modern Anolis species.

A Statistical Analysis of the Economic Drivers of Battery Energy Storage in Commercial Buildings: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Matthew; Simpkins, Travis; Cutler, Dylan

There is significant interest in using battery energy storage systems (BESS) to reduce peak demand charges, and therefore the life cycle cost of electricity, in commercial buildings. This paper explores the drivers of economic viability of BESS in commercial buildings through statistical analysis. A sample population of buildings was generated, a techno-economic optimization model was used to size and dispatch the BESS, and the resulting optimal BESS sizes were analyzed for relevant predictor variables. Explanatory regression analyses were used to demonstrate that peak demand charges are the most significant predictor of an economically viable battery, and that the shape ofmore » the load profile is the most significant predictor of the size of the battery.« less

A Statistical Analysis of the Economic Drivers of Battery Energy Storage in Commercial Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Matthew; Simpkins, Travis; Cutler, Dylan

There is significant interest in using battery energy storage systems (BESS) to reduce peak demand charges, and therefore the life cycle cost of electricity, in commercial buildings. This paper explores the drivers of economic viability of BESS in commercial buildings through statistical analysis. A sample population of buildings was generated, a techno-economic optimization model was used to size and dispatch the BESS, and the resulting optimal BESS sizes were analyzed for relevant predictor variables. Explanatory regression analyses were used to demonstrate that peak demand charges are the most significant predictor of an economically viable battery, and that the shape ofmore » the load profile is the most significant predictor of the size of the battery.« less

A numerical study on shear buckling capacity of Z-section steel purlin with opening

NASA Astrophysics Data System (ADS)

De'nan, Fatimah; Keong, Choong Kok; Hashim, Nor Salwani; Yuting, Ng

2017-10-01

Cold-formed Z-section steel purlin is one of the most commonly available steel purlin worldwide. A numerical study on Z-section steel purlin with opening under shear loading was carried out. Six (6) variables such as opening size, opening shape, section type, opening distance, opening position and opening arrangement were identified and tested to investigate their effect on shear capacity of Z-section steel purlin. Results indicated that the presence of web opening did not improve the shear behaviour of Z-section steel purlin. However, non-negligible improvement in terms of volume reduction was observed. Each 0.1D (where D is the section height) enlargement of opening size caused an approximate 10% drop in shear buckling capacity (SBC) while volume reduction (VR) increased exponentially. Diamond shape performed up to 55% better in SBC compared to circular shape opening but circular shape opening performed up to 24% better in VR. Sections with smaller section height had higher SBC compared to sections with bigger section height. Nevertheless, sections with bigger section height had higher VR. No significant difference in terms of shear buckling capacity was observed when opening distance was manipulated. Opening position had no effect on SBC and VR. Opening arrangement had no significant effect on SBC and VR. An optimal section of Z100-19 with 0.3D to 0.5D diamond shaped opening and an opening distance of 100mm centre to centre depending on design engineer's specification is proposed.

Fracture control method for composite tanks with load sharing liners

NASA Technical Reports Server (NTRS)

Bixler, W. D.

1975-01-01

The experimental program was based on the premise that the plastic sizing cycle, which each pressure vessel is subjected to prior to operation, acts as an effective proof test of the liner, screening out all flaws or cracks larger than a critical size. In doing so, flaw growth potential is available for cyclic operation at pressures less than the sizing pressure. Static fracture and cyclic life tests, involving laboratory type specimens and filament overwrapped tanks, were conducted on three liner materials: (1) 2219-T62 aluminum, (2) Inconel X750 STA, and (3) cryoformed 301 stainless steel. Variables included material condition, thickness, flaw size, flaw shape, temperature, sizing stress level, operating stress level and minimum-to-maximum operating stress ratio. From the empirical data base obtained, a procedure was established by which the service life of composite tanks with load sharing liners could be guaranteed with a high degree of confidence.

Techniques of contributing-area delineation for analysis of nonpoint-source contamination of Long Island, New York

USGS Publications Warehouse

Misut, P.

1995-01-01

Ninety shallow monitoring wells on Long Island, N.Y., were used to test the hypothesis that the correlation between the detection of volatile organic compounds (VOC's) at a well and explanatory variables representing land use, population density, and hydrogeologic conditions around the well is affected by the size and shape of the area defined as the contributing area. Explanatory variables are quantified through overlay of various specified contributing areas on 1:24 000-scale landuse and population-density geographic information system (GIS) coverages. Four methods of contributing-area delineation were used: (a) centering a circle of selected radius on the well site, (b) orienting a triangular area along the direction of horizontal ground-water flow to the well, (c) generating a shaped based on direction and magnitude of horizontal flow to the well, and (d) generating a shape based on three-dimensional particle pathlines backtracked from the well screen to the water table. The strongest correlations with VOC detections were obtained from circles of 400- to 1 000-meter radius. Improvement in correlation through delineations based on ground-water flow would require geographic overlay on more highly detailed GIS coverages than those used in the study.

The 2.1 Ga old Francevillian biota: biogenicity, taphonomy and biodiversity.

PubMed

El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E; Riboulleau, Armelle; Rollion Bard, Claire; Macchiarelli, Roberto; Ngombi Pemba, Lauriss; Hammarlund, Emma; Meunier, Alain; Moubiya Mouele, Idalina; Benzerara, Karim; Bernard, Sylvain; Boulvais, Philippe; Chaussidon, Marc; Cesari, Christian; Fontaine, Claude; Chi-Fru, Ernest; Garcia Ruiz, Juan Manuel; Gauthier-Lafaye, François; Mazurier, Arnaud; Pierson-Wickmann, Anne Catherine; Rouxel, Olivier; Trentesaux, Alain; Vecoli, Marco; Versteegh, Gerard J M; White, Lee; Whitehouse, Martin; Bekker, Andrey

2014-01-01

The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations ∼2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation. While most sedimentary successions deposited during this time interval have experienced thermal overprinting from burial diagenesis and metamorphism, the ca. 2.1 Ga black shales of the Francevillian B Formation (FB2) cropping out in southeastern Gabon have not. The Francevillian Formation contains centimeter-sized structures interpreted as organized and spatially discrete populations of colonial organisms living in an oxygenated marine ecosystem. Here, new material from the FB2 black shales is presented and analyzed to further explore its biogenicity and taphonomy. Our extended record comprises variably sized, shaped, and structured pyritized macrofossils of lobate, elongated, and rod-shaped morphologies as well as abundant non-pyritized disk-shaped macrofossils and organic-walled acritarchs. Combined microtomography, geochemistry, and sedimentary analysis suggest a biota fossilized during early diagenesis. The emergence of this biota follows a rise in atmospheric oxygen, which is consistent with the idea that surface oxygenation allowed the evolution and ecological expansion of complex megascopic life.

A mechanistic model for the evolution of multicellularity

NASA Astrophysics Data System (ADS)

Amado, André; Batista, Carlos; Campos, Paulo R. A.

2018-02-01

Through a mechanistic approach we investigate the formation of aggregates of variable sizes, accounting mechanisms of aggregation, dissociation, death and reproduction. In our model, cells can produce two metabolites, but the simultaneous production of both metabolites is costly in terms of fitness. Thus, the formation of larger groups can favor the aggregates to evolve to a configuration where division of labor arises. It is assumed that the states of the cells in a group are those that maximize organismal fitness. In the model it is considered that the groups can grow linearly, forming a chain, or compactly keeping a roughly spherical shape. Starting from a population consisting of single-celled organisms, we observe the formation of groups with variable sizes and usually much larger than two-cell aggregates. Natural selection can favor the formation of large groups, which allows the system to achieve new and larger fitness maxima.

Variable aperture-based ptychographical iterative engine method.

PubMed

Sun, Aihui; Kong, Yan; Meng, Xin; He, Xiaoliang; Du, Ruijun; Jiang, Zhilong; Liu, Fei; Xue, Liang; Wang, Shouyu; Liu, Cheng

2018-02-01

A variable aperture-based ptychographical iterative engine (vaPIE) is demonstrated both numerically and experimentally to reconstruct the sample phase and amplitude rapidly. By adjusting the size of a tiny aperture under the illumination of a parallel light beam to change the illumination on the sample step by step and recording the corresponding diffraction patterns sequentially, both the sample phase and amplitude can be faithfully reconstructed with a modified ptychographical iterative engine (PIE) algorithm. Since many fewer diffraction patterns are required than in common PIE and the shape, the size, and the position of the aperture need not to be known exactly, this proposed vaPIE method remarkably reduces the data acquisition time and makes PIE less dependent on the mechanical accuracy of the translation stage; therefore, the proposed technique can be potentially applied for various scientific researches. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Relationships between nesting populations of wading birds and habitat features along the Atlantic Coast

USGS Publications Warehouse

Erwin, R.M.; Spendelow, J.A.; Geissler, P.H.; Williams, B.K.; Whitman, William R.; Meredith, William H.

1987-01-01

Using previously published atlas data for 122 mixed-species wading bird colonies on islands along the Atlantic coast (Maine to Florida, 1976-77), we examined relationships between population sizes of 11 species of egrets, herons, ibises, and wood storks (Mycteria americana) and nine habitat variables. On nautical charts, we measured four island characteristics (area, length, width, shape), three isolation factors (distances to nearest island, mainland, and a water barrier),, and two variables related to potential feeding habitat within 5 km of the center of the colony (wetland area and land-water interface, i.e., the linear distance between the marsh/upland and all water bodies within the same 5-km radius). One univariable and five multivariable .procedures were used to determine which habitat features were best related to population size .(all species combined). Multicollinearity problems among the variables limited interpretation for most procedures. Both univariable and the multivariable procedures indicated that land-water interface was the most important of the nine variables, but for all models, less than 10% of the total variance was explained (rz is less than 0.10). The size of the colony was not related to the amount of wetland area (within 5-km).per se. Colony data showed better 'structure' when examined on the basis of geographic and disturbance gradients. Population sizes of colonies near man-altered habitats were compared with those surrounded by relatively natural habitats in three geographic zones: north, middle, and south. Significant differences were found in colony size among the three zones (south largest) and between disturbance types. Surprisingly, in all three zones, colonies near man-altered areas were larger on average than those near more natural habitats in this region. A possible reason for this difference is suggested.

The relationship between asymmetry, size and unusual venation in honey bees (Apis mellifera).

PubMed

Łopuch, S; Tofilski, A

2016-06-01

Despite the fact that symmetry is common in nature, it is rarely perfect. Because there is a wide range of phenotypes which differs from the average one, the asymmetry should increase along with deviation. Therefore, the aim of this study was to assess the level of asymmetry in normal individuals as well as in phenodeviants categorized as minor or major based on abnormalities in forewing venation in honey bees. Shape fluctuating asymmetry (FA) was lower in normal individuals and minor phenodeviants compared with major phenodeviants, whereas the former two categories were comparable in drones. In workers and queens, there were not significant differences in FA shape between categories. FA size was significantly lower in normal individuals compared with major phenodeviant drones and higher compared with minor phenodeviant workers. In queens, there were no significant differences between categories. The correlation between FA shape and FA size was significantly positive in drones, and insignificant in workers and queens. Moreover, a considerable level of directional asymmetry was found as the right wing was constantly bigger than the left one. Surprisingly, normal individuals were significantly smaller than minor phenodeviants in queens and drones, and they were comparable with major phenodeviants in all castes. The correlation between wing size and wing asymmetry was negative, indicating that smaller individuals were more asymmetrical. The high proportion of phenodeviants in drones compared with workers and queens confirmed their large variability. Thus, the results of the present study showed that minor phenodeviants were not always intermediate as might have been expected.

Screening actuator locations for static shape control

NASA Technical Reports Server (NTRS)

Haftka, Raphael T.

1990-01-01

Correction of shape distortion due to zero-mean normally distributed errors in structural sizes which are random variables is examined. A bound on the maximum improvement in the expected value of the root-mean-square shape error is obtained. The shape correction associated with the optimal actuators is also characterized. An actuator effectiveness index is developed and shown to be helpful in screening actuator locations in the structure. The results are specialized to a simple form for truss structures composed of nominally identical members. The bound and effectiveness index are tested on a 55-m radiometer antenna truss structure. It is found that previously obtained results for optimum actuators had a performance close to the bound obtained here. Furthermore, the actuators associated with the optimum design are shown to have high effectiveness indices. Since only a small fraction of truss elements tend to have high effectiveness indices, the proposed screening procedure can greatly reduce the number of truss members that need to be considered as actuator sites.

Heritability of mandibular cephalometric variables in twins with completed craniofacial growth.

PubMed

Šidlauskas, Mantas; Šalomskienė, Loreta; Andriuškevičiūtė, Irena; Šidlauskienė, Monika; Labanauskas, Žygimantas; Vasiliauskas, Arūnas; Kupčinskas, Limas; Juzėnas, Simonas; Šidlauskas, Antanas

2016-10-01

To determine genetic and environmental impact on mandibular morphology using lateral cephalometric analysis of twins with completed mandibular growth and deoxyribonucleic acid (DNA) based zygosity determination. The 39 cephalometric variables of 141 same gender adult pair of twins were analysed. Zygosity was determined using 15 specific DNA markers and cervical vertebral maturation method was used to assess completion of the mandibular growth. A genetic analysis was performed using maximum likelihood genetic structural equation modelling (GSEM). The genetic heritability estimates of angular variables describing horizontal mandibular position in relationship to cranial base and maxilla were considerably higher than in those describing vertical position. The mandibular skeletal cephalometric variables also showed high heritability estimates with angular measurements being considerably higher than linear ones. Results of this study indicate that the angular measurements representing mandibular skeletal morphology (mandibular form) have greater genetic determination than the linear measurements (mandibular size). The shape and sagittal position of the mandible is under stronger genetic control, than is its size and vertical relationship to cranial base. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Stability, surface features, and atom leaching of palladium nanoparticles: toward prediction of catalytic functionality.

PubMed

Ramezani-Dakhel, Hadi; Mirau, Peter A; Naik, Rajesh R; Knecht, Marc R; Heinz, Hendrik

2013-04-21

Surfactant-stabilized metal nanoparticles have shown promise as catalysts although specific surface features and their influence on catalytic performance have not been well understood. We quantify the thermodynamic stability, the facet composition of the surface, and distinct atom types that affect rates of atom leaching for a series of twenty near-spherical Pd nanoparticles of 1.8 to 3.1 nm size using computational models. Cohesive energies indicate higher stability of certain particles that feature an approximate 60/20/20 ratio of {111}, {100}, and {110} facets while less stable particles exhibit widely variable facet composition. Unique patterns of atom types on the surface cause apparent differences in binding energies and changes in reactivity. Estimates of the relative rate of atom leaching as a function of particle size were obtained by the summation of Boltzmann-weighted binding energies over all surface atoms. Computed leaching rates are in good qualitative correlation with the measured catalytic activity of peptide-stabilized Pd nanoparticles of the same shape and size in Stille coupling reactions. The agreement supports rate-controlling contributions by atom leaching in the presence of reactive substrates. The computational approach provides a pathway to estimate the catalytic activity of metal nanostructures of engineered shape and size, and possible further refinements are described.

Within-litter differences in personality and physiology relate to size differences among siblings in cavies.

PubMed

Guenther, A; Trillmich, F

2015-06-01

Many aspects of an animal's early life potentially contribute to long-term individual differences in physiology and behaviour. From several studies on birds and mammals it is known that the early family environment is one of the most prominent factors influencing early development. Most of these studies were conducted on highly altricial species. Here we asked whether in the highly precocial cavy (Cavia aperea) the size rank within a litter, i.e. whether an individual is born as the heaviest, the lightest or an intermediate sibling, affects personality traits directly after birth and after independence. Furthermore, we investigated whether individual states (early growth, baseline cortisol and resting metabolic rate) differ between siblings of different size ranks and assessed their relation to personality traits. Siblings of the same litter differed in personality traits as early as three days after birth. Pups born heaviest in the litter were more explorative and in general more risk-prone than their smaller siblings. Physiological state variables were tightly correlated with personality traits and also influenced by the size rank within litter, suggesting that the size relative to littermates constitutes an important factor in shaping an individual's developmental trajectory. Our data add valuable information on how personalities are shaped during early phases of life and indicate the stability of developmentally influenced behavioural and physiological traits. Copyright © 2015 Elsevier Inc. All rights reserved.

Sharp and round shapes of seen objects have distinct influences on vowel and consonant articulation.

PubMed

Vainio, L; Tiainen, M; Tiippana, K; Rantala, A; Vainio, M

2017-07-01

The shape and size-related sound symbolism phenomena assume that, for example, the vowel [i] and the consonant [t] are associated with sharp-shaped and small-sized objects, whereas [ɑ] and [m] are associated with round and large objects. It has been proposed that these phenomena are mostly based on the involvement of articulatory processes in representing shape and size properties of objects. For example, [i] might be associated with sharp and small objects, because it is produced by a specific front-close shape of articulators. Nevertheless, very little work has examined whether these object properties indeed have impact on speech sound vocalization. In the present study, the participants were presented with a sharp- or round-shaped object in a small or large size. They were required to pronounce one out of two meaningless speech units (e.g., [i] or [ɑ]) according to the size or shape of the object. We investigated how a task-irrelevant object property (e.g., the shape when responses are made according to size) influences reaction times, accuracy, intensity, fundamental frequency, and formant 1 and formant 2 of vocalizations. The size did not influence vocal responses but shape did. Specifically, the vowel [i] and consonant [t] were vocalized relatively rapidly when the object was sharp-shaped, whereas [u] and [m] were vocalized relatively rapidly when the object was round-shaped. The study supports the view that the shape-related sound symbolism phenomena might reflect mapping of the perceived shape with the corresponding articulatory gestures.

On the comparison of the strength of morphological integration across morphometric datasets.

PubMed

Adams, Dean C; Collyer, Michael L

2016-11-01

Evolutionary morphologists frequently wish to understand the extent to which organisms are integrated, and whether the strength of morphological integration among subsets of phenotypic variables differ among taxa or other groups. However, comparisons of the strength of integration across datasets are difficult, in part because the summary measures that characterize these patterns (RV coefficient and r PLS ) are dependent both on sample size and on the number of variables. As a solution to this issue, we propose a standardized test statistic (a z-score) for measuring the degree of morphological integration between sets of variables. The approach is based on a partial least squares analysis of trait covariation, and its permutation-based sampling distribution. Under the null hypothesis of a random association of variables, the method displays a constant expected value and confidence intervals for datasets of differing sample sizes and variable number, thereby providing a consistent measure of integration suitable for comparisons across datasets. A two-sample test is also proposed to statistically determine whether levels of integration differ between datasets, and an empirical example examining cranial shape integration in Mediterranean wall lizards illustrates its use. Some extensions of the procedure are also discussed. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Spatial trends in tidal flat shape and associated environmental parameters in South San Francisco Bay

USGS Publications Warehouse

Bearman, J.A.; Friedrichs, Carl T.; Jaffe, B.E.; Foxgrover, A.C.

2010-01-01

Spatial trends in the shape of profiles of South San Francisco Bay (SSFB) tidal flats are examined using bathymetric and lidar data collected in 2004 and 2005. Eigenfunction analysis reveals a dominant mode of morphologic variability related to the degree of convexity or concavity in the cross-shore profileindicative of (i) depositional, tidally dominant or (ii) erosional, wave impacted conditions. Two contrasting areas of characteristic shapenorth or south of a constriction in estuary width located near the Dumbarton Bridgeare recognized. This pattern of increasing or decreasing convexity in the inner or outer estuary is correlated to spatial variability in external and internal environmental parameters, and observational results are found to be largely consistent with theoretical expectations. Tidal flat convexity in SSFB is observed to increase (in decreasing order of significance) in response to increased deposition, increased tidal range, decreased fetch length, decreased sediment grain size, and decreased tidal flat width. ?? 2010 Coastal Education and Research Foundation.

Human induced rotation and reorganization of the brain of domestic dogs.

PubMed

Roberts, Taryn; McGreevy, Paul; Valenzuela, Michael

2010-07-26

Domestic dogs exhibit an extraordinary degree of morphological diversity. Such breed-to-breed variability applies equally to the canine skull, however little is known about whether this translates to systematic differences in cerebral organization. By looking at the paramedian sagittal magnetic resonance image slice of canine brains across a range of animals with different skull shapes (N = 13), we found that the relative reduction in skull length compared to width (measured by Cephalic Index) was significantly correlated to a progressive ventral pitching of the primary longitudinal brain axis (r = 0.83), as well as with a ventral shift in the position of the olfactory lobe (r = 0.81). Furthermore, these findings were independent of estimated brain size or body weight. Since brachycephaly has arisen from generations of highly selective breeding, this study suggests that the remarkable diversity in domesticated dogs' body shape and size appears to also have led to human-induced adaptations in the organization of the canine brain.

Renormalization-group theory for finite-size scaling in extreme statistics

NASA Astrophysics Data System (ADS)

Györgyi, G.; Moloney, N. R.; Ozogány, K.; Rácz, Z.; Droz, M.

2010-04-01

We present a renormalization-group (RG) approach to explain universal features of extreme statistics applied here to independent identically distributed variables. The outlines of the theory have been described in a previous paper, the main result being that finite-size shape corrections to the limit distribution can be obtained from a linearization of the RG transformation near a fixed point, leading to the computation of stable perturbations as eigenfunctions. Here we show details of the RG theory which exhibit remarkable similarities to the RG known in statistical physics. Besides the fixed points explaining universality, and the least stable eigendirections accounting for convergence rates and shape corrections, the similarities include marginally stable perturbations which turn out to be generic for the Fisher-Tippett-Gumbel class. Distribution functions containing unstable perturbations are also considered. We find that, after a transitory divergence, they return to the universal fixed line at the same or at a different point depending on the type of perturbation.

Convergence and Divergence in the Evolution of Cat Skulls: Temporal and Spatial Patterns of Morphological Diversity

PubMed Central

Sakamoto, Manabu; Ruta, Marcello

2012-01-01

Background Studies of biological shape evolution are greatly enhanced when framed in a phylogenetic perspective. Inclusion of fossils amplifies the scope of macroevolutionary research, offers a deep-time perspective on tempo and mode of radiations, and elucidates life-trait changes. We explore the evolution of skull shape in felids (cats) through morphometric analyses of linear variables, phylogenetic comparative methods, and a new cladistic study of saber-toothed cats. Methodology/Principal Findings A new phylogenetic analysis supports the monophyly of saber-toothed cats (Machairodontinae) exclusive of Felinae and some basal felids, but does not support the monophyly of various saber-toothed tribes and genera. We quantified skull shape variation in 34 extant and 18 extinct species using size-adjusted linear variables. These distinguish taxonomic group membership with high accuracy. Patterns of morphospace occupation are consistent with previous analyses, for example, in showing a size gradient along the primary axis of shape variation and a separation between large and small-medium cats. By combining the new phylogeny with a molecular tree of extant Felinae, we built a chronophylomorphospace (a phylogeny superimposed onto a two-dimensional morphospace through time). The evolutionary history of cats was characterized by two major episodes of morphological divergence, one marking the separation between saber-toothed and modern cats, the other marking the split between large and small-medium cats. Conclusions/Significance Ancestors of large cats in the ‘Panthera’ lineage tend to occupy, at a much later stage, morphospace regions previously occupied by saber-toothed cats. The latter radiated out into new morphospace regions peripheral to those of extant large cats. The separation between large and small-medium cats was marked by considerable morphologically divergent trajectories early in feline evolution. A chronophylomorphospace has wider applications in reconstructing temporal transitions across two-dimensional trait spaces, can be used in ecophenotypical and functional diversity studies, and may reveal novel patterns of morphospace occupation. PMID:22792186

Holographic photolysis of caged neurotransmitters

PubMed Central

Lutz, Christoph; Otis, Thomas S.; DeSars, Vincent; Charpak, Serge; DiGregorio, David A.; Emiliani, Valentina

2009-01-01

Stimulation of light-sensitive chemical probes has become a powerful tool for the study of dynamic signaling processes in living tissue. Classically, this approach has been constrained by limitations of lens–based and point-scanning illumination systems. Here we describe a novel microscope configuration that incorporates a nematic liquid crystal spatial light modulator (LC-SLM) to generate holographic patterns of illumination. This microscope can produce illumination spots of variable size and number and patterns shaped to precisely match user-defined elements in a specimen. Using holographic illumination to photolyse caged glutamate in brain slices, we demonstrate that shaped excitation on segments of neuronal dendrites and simultaneous, multi-spot excitation of different dendrites enables precise spatial and rapid temporal control of glutamate receptor activation. By allowing the excitation volume shape to be tailored precisely, the holographic microscope provides an extremely flexible method for activation of various photosensitive proteins and small molecules. PMID:19160517

Stereoscopic shape discrimination is well preserved across changes in object size.

PubMed

Norman, J Farley; Swindle, Jessica M; Jennings, L RaShae; Mullins, Elizabeth M; Beers, Amanda M

2009-06-01

A single experiment evaluated human observers' ability to discriminate the shape of solid objects that varied in size and orientation in depth. The object shapes were defined by binocular disparity, Lambertian shading, and texture. The object surfaces were smoothly curved and had naturalistic shapes, resembling those of water-smoothed granite rocks. On any given trial, two objects were presented that were either the same or different in terms of shape. When the "same" objects were presented, they differed in their orientation in depth by 25 degrees , 45 degrees , or 65 degrees . The observers were required to judge whether any given pair of objects was the "same" or "different" in terms of shape. The size of the objects was also varied by amounts up to +/-40% relative to the standard size. The observers' shape discrimination performance was strongly affected by the magnitude of the orientation changes in depth - thus, their performance was viewpoint dependent. In contrast, the observers' shape discrimination abilities were only slightly affected by changes in the overall size of the objects. It appears that human observers can recognize the three-dimensional shape of objects in a manner that is relatively independent of size.

Size-Sensitive Perceptual Representations Underlie Visual and Haptic Object Recognition

PubMed Central

Craddock, Matt; Lawson, Rebecca

2009-01-01

A variety of similarities between visual and haptic object recognition suggests that the two modalities may share common representations. However, it is unclear whether such common representations preserve low-level perceptual features or whether transfer between vision and haptics is mediated by high-level, abstract representations. Two experiments used a sequential shape-matching task to examine the effects of size changes on unimodal and crossmodal visual and haptic object recognition. Participants felt or saw 3D plastic models of familiar objects. The two objects presented on a trial were either the same size or different sizes and were the same shape or different but similar shapes. Participants were told to ignore size changes and to match on shape alone. In Experiment 1, size changes on same-shape trials impaired performance similarly for both visual-to-visual and haptic-to-haptic shape matching. In Experiment 2, size changes impaired performance on both visual-to-haptic and haptic-to-visual shape matching and there was no interaction between the cost of size changes and direction of transfer. Together the unimodal and crossmodal matching results suggest that the same, size-specific perceptual representations underlie both visual and haptic object recognition, and indicate that crossmodal memory for objects must be at least partly based on common perceptual representations. PMID:19956685

Joint detection and tracking of size-varying infrared targets based on block-wise sparse decomposition

NASA Astrophysics Data System (ADS)

Li, Miao; Lin, Zaiping; Long, Yunli; An, Wei; Zhou, Yiyu

2016-05-01

The high variability of target size makes small target detection in Infrared Search and Track (IRST) a challenging task. A joint detection and tracking method based on block-wise sparse decomposition is proposed to address this problem. For detection, the infrared image is divided into overlapped blocks, and each block is weighted on the local image complexity and target existence probabilities. Target-background decomposition is solved by block-wise inexact augmented Lagrange multipliers. For tracking, label multi-Bernoulli (LMB) tracker tracks multiple targets taking the result of single-frame detection as input, and provides corresponding target existence probabilities for detection. Unlike fixed-size methods, the proposed method can accommodate size-varying targets, due to no special assumption for the size and shape of small targets. Because of exact decomposition, classical target measurements are extended and additional direction information is provided to improve tracking performance. The experimental results show that the proposed method can effectively suppress background clutters, detect and track size-varying targets in infrared images.

Phenotypic plasticity in haptoral structures of Ligophorus cephali (Monogenea: Dactylogyridae) on the flathead mullet (Mugil cephalus): a geometric morphometric approach.

PubMed

Rodríguez-González, Abril; Míguez-Lozano, Raúl; Llopis-Belenguer, Cristina; Balbuena, Juan Antonio

2015-04-01

Evaluating phenotypic plasticity in attachment organs of parasites can provide information on the capacity to colonise new hosts and illuminate evolutionary processes driving host specificity. We analysed the variability in shape and size of the dorsal and ventral anchors of Ligophorus cephali from Mugil cephalus by means of geometric morphometrics and multivariate statistics. We also assessed the morphological integration between anchors and between the roots and points in order to gain insight into their functional morphology. Dorsal and ventral anchors showed a similar gradient of overall shape variation, but the amount of localised changes was much higher in the former. Statistical models describing variations in shape and size revealed clear differences between anchors. The dorsal anchor/bar complex seems more mobile than the ventral one in Ligophorus, and these differences may reflect different functional roles in attachment to the gills. The lower residual variation associated with the ventral anchor models suggests a tighter control of their shape and size, perhaps because these anchors seem to be responsible for firmer attachment and their size and shape would allow more effective responses to characteristics of the microenvironment within the individual host. Despite these putative functional differences, the high level of morphological integration indicates a concerted action between anchors. In addition, we found a slight, although significant, morphological integration between roots and points in both anchors, which suggests that a large fraction of the observed phenotypic variation does not compromise the functional role of anchors as levers. Given the low level of genetic variation in our sample, it is likely that much of the morphological variation reflects host-driven plastic responses. This supports the hypothesis of monogenean specificity through host-switching and rapid speciation. The present study demonstrates the potential of geometric morphometrics to provide new and previously unexplored insights into the functional morphology of attachment and evolutionary processes of host-parasite coevolution. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Oleic acid-associated bronchiolitis obliterans-organizing pneumonia in beagle dogs.

PubMed

Li, X; Botts, S; Morton, D; Knickerbocker, M J; Adler, R

2006-03-01

Accidental intra-airway exposure of dogs with pure oleic acid produced bronchiolitis obliterans and bronchopneumonia. Pulmonary changes included multifocal to coalescing necrosis of bronchioles and adjacent alveoli, hemorrhage, inflammation, and exudation of fibrin. Hyperplasia of bronchiolar and alveolar epithelial cells and proliferation of loose fibrovascular connective tissue formed polyps or plugs of variable size and shape. Polyps in the airways primarily consisted of fibroblasts with loose or myxoid stroma and were variably covered with attenuated epithelial cells. Some polyps had prominent vasculature, mixed inflammatory cell infiltration, and/or necrosis. Polyps or plugs variably effaced bronchioles and adjacent alveoli. The changes closely resembled human bronchiolitis obliterans-organizing pneumonia (BOOP). Controlled intra-airway delivery of oleic acid in dogs may be a potential animal model of obstructive pulmonary diseases such as BOOP or bronchiolitis obliterans.

On the melt infiltration of copper coated silicon carbide with an aluminium alloy

NASA Technical Reports Server (NTRS)

Asthana, R.; Rohatgi, P. K.

1992-01-01

Pressure-assisted infiltration of porous compacts of Cu coated and uncoated single crystals of platelet shaped alpha (hexagonal) SiC was used to study infiltration dynamics and particulate wettability with a 2014 Al alloy. The infiltration lengths were measured for a range of experimental variables which included infiltration pressure, infiltration time, and SiC size. A threshold pressure (P(th)) for flow initiation through compacts was identified from an analysis of infiltration data; P(th) decreased while penetration lengths increased with increasing SiC size (more fundamentally, due to changes in interparticle pore size) and with increasing infiltration times. Cu coated SiC led to lower P(th) and 60-80 percent larger penetration lengths compared to uncoated SiC under identical processing conditions.

Snow grain size and shape distributions in northern Canada

NASA Astrophysics Data System (ADS)

Langlois, A.; Royer, A.; Montpetit, B.; Roy, A.

2016-12-01

Pioneer snow work in the 1970s and 1980s proposed new approaches to retrieve snow depth and water equivalent from space using passive microwave brightness temperatures. Numerous research work have led to the realization that microwave approaches depend strongly on snow grain morphology (size and shape), which was poorly parameterized since recently, leading to strong biases in the retrieval calculations. Related uncertainties from space retrievals and the development of complex thermodynamic multilayer snow and emission models motivated several research works on the development of new approaches to quantify snow grain metrics given the lack of field measurements arising from the sampling constraints of such variable. This presentation focuses on the unknown size distribution of snow grain sizes. Our group developed a new approach to the `traditional' measurements of snow grain metrics where micro-photographs of snow grains are taken under angular directional LED lighting. The projected shadows are digitized so that a 3D reconstruction of the snow grains is possible. This device has been used in several field campaigns and over the years a very large dataset was collected and is presented in this paper. A total of 588 snow photographs from 107 snowpits collected during the European Space Agency (ESA) Cold Regions Hydrology high-resolution Observatory (CoReH2O) mission concept field campaign, in Churchill, Manitoba Canada (January - April 2010). Each of the 588 photographs was classified as: depth hoar, rounded, facets and precipitation particles. A total of 162,516 snow grains were digitized across the 588 photographs, averaging 263 grains/photo. Results include distribution histograms for 5 `size' metrics (projected area, perimeter, equivalent optical diameter, minimum axis and maximum axis), and 2 `shape' metrics (eccentricity, major/minor axis ratio). Different cumulative histograms are found between the grain types, and proposed fits are presented with the Kernel distribution function. Finally, a comparison with the Specific Surface Area (SSA) derived from reflectance values using the Infrared Integrating Sphere (IRIS) highlight different power statistical fits for the 5 `size' metrics.

An analysis of beak shape variation in two ages of domestic turkeys (Meleagris gallopavo) using landmark-based geometric morphometrics.

PubMed

Dalton, Hillary A; Wood, Benjamin J; Widowski, Tina M; Guerin, Michele T; Torrey, Stephanie

2017-01-01

The objective of this study was to assess beak shape variation in domestic turkeys (Meleagris gallopavo) and determine the effects of age, sex, and beak size on beak shape variation using geometric morphometrics. Dorsal and right lateral images were taken of 2442 turkeys at 6 and 18.5 weeks of age. Landmarks were digitized in tpsDig in three analyses of the dorsal upper mandible, lateral upper mandible, and lateral lower mandible shape of each turkey at both ages. The coordinate data were then subjected to a principal components analysis (PCA), multivariate regression, and a canonical variates analysis (CVA) with a Procrustes ANOVA in MorphoJ. For the dorsal images, three principal components (PCs) showed beak shape variation ranged from long, narrow, and pointed to short, wide, and blunt upper mandibles at both ages (6 weeks: 95.36%, 18.5 weeks: 92.21%). Three PCs showed the lateral upper mandible shape variation ranged from long, wide beaks with long, curved beak tips to short, narrow beaks with short, pointed beak tips at both ages (6 weeks: 94.91%, 18.5 weeks: 94.33%). Three PCs also explained 97.80% (6 weeks) and 97.11% (18.5 weeks) of the lateral lower mandible shape variation ranging from wide and round to narrow and thin lower mandibles with superior/inferior beak tip shifts. Beak size accounted for varying proportions of the beak shape variation (0.96-54.76%; P < 0.0001) in the three analyses of each age group. For all the analyses, the CVA showed sexual dimorphism in beak shape (P < 0.0001) with female upper mandibles appearing wider and blunter dorsally with long, curved beak tips laterally. Whereas male turkey upper mandibles had a narrow, pointed dorsal appearance and short, pointed beak tips laterally. Future applications of beak shape variability could have a genetic and welfare value by incorporating beak shape variation to select for specific turkey beak phenotypes as an alternative to beak treatment.

An analysis of beak shape variation in two ages of domestic turkeys (Meleagris gallopavo) using landmark-based geometric morphometrics

PubMed Central

Widowski, Tina M.; Guerin, Michele T.

2017-01-01

The objective of this study was to assess beak shape variation in domestic turkeys (Meleagris gallopavo) and determine the effects of age, sex, and beak size on beak shape variation using geometric morphometrics. Dorsal and right lateral images were taken of 2442 turkeys at 6 and 18.5 weeks of age. Landmarks were digitized in tpsDig in three analyses of the dorsal upper mandible, lateral upper mandible, and lateral lower mandible shape of each turkey at both ages. The coordinate data were then subjected to a principal components analysis (PCA), multivariate regression, and a canonical variates analysis (CVA) with a Procrustes ANOVA in MorphoJ. For the dorsal images, three principal components (PCs) showed beak shape variation ranged from long, narrow, and pointed to short, wide, and blunt upper mandibles at both ages (6 weeks: 95.36%, 18.5 weeks: 92.21%). Three PCs showed the lateral upper mandible shape variation ranged from long, wide beaks with long, curved beak tips to short, narrow beaks with short, pointed beak tips at both ages (6 weeks: 94.91%, 18.5 weeks: 94.33%). Three PCs also explained 97.80% (6 weeks) and 97.11% (18.5 weeks) of the lateral lower mandible shape variation ranging from wide and round to narrow and thin lower mandibles with superior/inferior beak tip shifts. Beak size accounted for varying proportions of the beak shape variation (0.96–54.76%; P < 0.0001) in the three analyses of each age group. For all the analyses, the CVA showed sexual dimorphism in beak shape (P < 0.0001) with female upper mandibles appearing wider and blunter dorsally with long, curved beak tips laterally. Whereas male turkey upper mandibles had a narrow, pointed dorsal appearance and short, pointed beak tips laterally. Future applications of beak shape variability could have a genetic and welfare value by incorporating beak shape variation to select for specific turkey beak phenotypes as an alternative to beak treatment. PMID:28934330

Subcutaneous haemangiosarcoma in a cockatiel (Nymphicus hollandicus).

PubMed

Sledge, D G; Radi, Z A; Miller, D L; Lynn, B S

2006-08-01

An ulcerated, 1 x 0.5 cm, subcutaneous mass on the craniolateral aspect of the right tibiotarsus of a 4-year-old male cockatiel was removed. Histologically, the neoplasm was non-encapsulated, infiltrative and composed of irregular vascular channels lined by branching and variably sized spindle-shaped cells with large vesicular nuclei, prominent nucleoli and rare mitoses. Surrounding these vascular channels were fibroblasts and mixed inflammatory cells. Neoplastic cells had diffuse immunoreactivity to factor VIII supporting a diagnosis of haemangiosarcoma.

Chemical and Biological Sensor Standards Study

DTIC Science & Technology

2005-01-01

that is utilized in lieu of Bacillus anthracis in testing biological agent sensors; both are gram positive, spore forming bacteria that have similar...for a given agent dosage is as follows: C = D r 3 f B Tη4π 3 ρ See the table for the variable designation. Using Bacillus anthracis as an example...e.g., genetic similarity, aerosol dynamics, size, shape, etc.) of the agent of interest. For example, Bacillus globigii is a widely used bacterium

Novel high-resolution computed tomography-based radiomic classifier for screen-identified pulmonary nodules in the National Lung Screening Trial.

PubMed

Peikert, Tobias; Duan, Fenghai; Rajagopalan, Srinivasan; Karwoski, Ronald A; Clay, Ryan; Robb, Richard A; Qin, Ziling; Sicks, JoRean; Bartholmai, Brian J; Maldonado, Fabien

2018-01-01

Optimization of the clinical management of screen-detected lung nodules is needed to avoid unnecessary diagnostic interventions. Herein we demonstrate the potential value of a novel radiomics-based approach for the classification of screen-detected indeterminate nodules. Independent quantitative variables assessing various radiologic nodule features such as sphericity, flatness, elongation, spiculation, lobulation and curvature were developed from the NLST dataset using 726 indeterminate nodules (all ≥ 7 mm, benign, n = 318 and malignant, n = 408). Multivariate analysis was performed using least absolute shrinkage and selection operator (LASSO) method for variable selection and regularization in order to enhance the prediction accuracy and interpretability of the multivariate model. The bootstrapping method was then applied for the internal validation and the optimism-corrected AUC was reported for the final model. Eight of the originally considered 57 quantitative radiologic features were selected by LASSO multivariate modeling. These 8 features include variables capturing Location: vertical location (Offset carina centroid z), Size: volume estimate (Minimum enclosing brick), Shape: flatness, Density: texture analysis (Score Indicative of Lesion/Lung Aggression/Abnormality (SILA) texture), and surface characteristics: surface complexity (Maximum shape index and Average shape index), and estimates of surface curvature (Average positive mean curvature and Minimum mean curvature), all with P<0.01. The optimism-corrected AUC for these 8 features is 0.939. Our novel radiomic LDCT-based approach for indeterminate screen-detected nodule characterization appears extremely promising however independent external validation is needed.

Extraction of liver volumetry based on blood vessel from the portal phase CT dataset

NASA Astrophysics Data System (ADS)

Maklad, Ahmed S.; Matsuhiro, Mikio; Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Utsunomiya, Tohru; Shimada, Mitsuo

2012-02-01

At liver surgery planning stage, the liver volumetry would be essential for surgeons. Main problem at liver extraction is the wide variability of livers in shapes and sizes. Since, hepatic blood vessels structure varies from a person to another and covers liver region, the present method uses that information for extraction of liver in two stages. The first stage is to extract abdominal blood vessels in the form of hepatic and nonhepatic blood vessels. At the second stage, extracted vessels are used to control extraction of liver region automatically. Contrast enhanced CT datasets at only the portal phase of 50 cases is used. Those data include 30 abnormal livers. A reference for all cases is done through a comparison of two experts labeling results and correction of their inter-reader variability. Results of the proposed method agree with the reference at an average rate of 97.8%. Through application of different metrics mentioned at MICCAI workshop for liver segmentation, it is found that: volume overlap error is 4.4%, volume difference is 0.3%, average symmetric distance is 0.7 mm, Root mean square symmetric distance is 0.8 mm, and maximum distance is 15.8 mm. These results represent the average of overall data and show an improved accuracy compared to current liver segmentation methods. It seems to be a promising method for extraction of liver volumetry of various shapes and sizes.

Identification of major and minor QTL for ecologically important morphological traits in three-spined sticklebacks (Gasterosteus aculeatus).

PubMed

Liu, Jun; Shikano, Takahito; Leinonen, Tuomas; Cano, José Manuel; Li, Meng-Hua; Merilä, Juha

2014-04-16

Quantitative trait locus (QTL) mapping studies of Pacific three-spined sticklebacks (Gasterosteus aculeatus) have uncovered several genomic regions controlling variability in different morphological traits, but QTL studies of Atlantic sticklebacks are lacking. We mapped QTL for 40 morphological traits, including body size, body shape, and body armor, in a F2 full-sib cross between northern European marine and freshwater three-spined sticklebacks. A total of 52 significant QTL were identified at the 5% genome-wide level. One major QTL explaining 74.4% of the total variance in lateral plate number was detected on LG4, whereas several major QTL for centroid size (a proxy for body size), and the lengths of two dorsal spines, pelvic spine, and pelvic girdle were mapped on LG21 with the explained variance ranging from 27.9% to 57.6%. Major QTL for landmark coordinates defining body shape variation also were identified on LG21, with each explaining ≥15% of variance in body shape. Multiple QTL for different traits mapped on LG21 overlapped each other, implying pleiotropy and/or tight linkage. Thus, apart from providing confirmatory data to support conclusions born out of earlier QTL studies of Pacific sticklebacks, this study also describes several novel QTL of both major and smaller effect for ecologically important traits. The finding that many major QTL mapped on LG21 suggests that this linkage group might be a hotspot for genetic determinants of ecologically important morphological traits in three-spined sticklebacks.

Bony pelvic canal size and shape in relation to body proportionality in humans.

PubMed

Kurki, Helen K

2013-05-01

Obstetric selection acts on the female pelvic canal to accommodate the human neonate and contributes to pelvic sexual dimorphism. There is a complex relationship between selection for obstetric sufficiency and for overall body size in humans. The relationship between selective pressures may differ among populations of different body sizes and proportions, as pelvic canal dimensions vary among populations. Size and shape of the pelvic canal in relation to body size and shape were examined using nine skeletal samples (total female n = 57; male n = 84) from diverse geographical regions. Pelvic, vertebral, and lower limb bone measurements were collected. Principal component analyses demonstrate pelvic canal size and shape differences among the samples. Male multivariate variance in pelvic shape is greater than female variance for North and South Africans. High-latitude samples have larger and broader bodies, and pelvic canals of larger size and, among females, relatively broader medio-lateral dimensions relative to low-latitude samples, which tend to display relatively expanded inlet antero-posterior (A-P) and posterior canal dimensions. Differences in canal shape exist among samples that are not associated with latitude or body size, suggesting independence of some canal shape characteristics from body size and shape. The South Africans are distinctive with very narrow bodies and small pelvic inlets relative to an elongated lower canal in A-P and posterior lengths. Variation in pelvic canal geometry among populations is consistent with a high degree of evolvability in the human pelvis. Copyright © 2013 Wiley Periodicals, Inc.

WIDE AND THICK GRAIN 1, which encodes an otubain-like protease with deubiquitination activity, influences grain size and shape in rice.

PubMed

Huang, Ke; Wang, Dekai; Duan, Penggen; Zhang, Baolan; Xu, Ran; Li, Na; Li, Yunhai

2017-09-01

Grain size and shape are two crucial traits that influence grain yield and grain appearance in rice. Although several factors that affect grain size have been described in rice, the molecular mechanisms underlying the determination of grain size and shape are still elusive. In this study we report that WIDE AND THICK GRAIN 1 (WTG1) functions as an important factor determining grain size and shape in rice. The wtg1-1 mutant exhibits wide, thick, short and heavy grains and also shows an increased number of grains per panicle. WTG1 determines grain size and shape mainly by influencing cell expansion. WTG1 encodes an otubain-like protease, which shares similarity with human OTUB1. Biochemical analyses indicate that WTG1 is a functional deubiquitinating enzyme, and the mutant protein (wtg1-1) loses this deubiquitinating activity. WTG1 is expressed in developing grains and panicles, and the GFP-WTG1 fusion protein is present in the nucleus and cytoplasm. Overexpression of WTG1 results in narrow, thin, long grains due to narrow and long cells, further supporting the role of WTG1 in determining grain size and shape. Thus, our findings identify the otubain-like protease WTG1 to be an important factor that determines grain size and shape, suggesting that WTG1 has the potential to improve grain size and shape in rice. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Shape, size, and maturity trajectories of the human ilium.

PubMed

Wilson, Laura A B; Ives, Rachel; Cardoso, Hugo F V; Humphrey, Louise T

2015-01-01

Morphological traits of the ilium have consistently been more successful for juvenile sex determination than have techniques applied to other skeletal elements, however relatively little is known about the ontogeny and maturation of size and shape dimorphism in the ilium. We use a geometric morphometric approach to quantitatively separate the ontogeny of size and shape of the ilium, and analyze interpopulation differences in the onset, rate and patterning of sexual dimorphism. We captured the shape of three traits for a total of 191 ilia from Lisbon (Portugal) and London (UK) samples of known age and sex (0-17 years). Our results indicate that a) there is a clear dissociation between the ontogeny of size and shape in males and females, b) the ontogeny of size and shape are each defined by non-linear trajectories that differ between the sexes, c) there are interpopulation differences in ontogenetic shape trajectories, which point to population-specific patterning in the attainment of sexual dimorphism, and d) the rate of shape maturation and size maturation is typically higher for females than males. Male and female shape differences in the ilium are brought about by trajectory divergence. Differences in size and shape maturation between the sexes suggest that maturity may confound our ability to discriminate between the sexes by introducing variation not accounted for in age-based groupings. The accuracy of sex determination methods using the ilium may be improved by the use of different traits for particular age groups, to capture the ontogenetic development of shape in both sexes. © 2014 Wiley Periodicals, Inc.

Gas Dispersion Coefficients in Variably Saturated and Differently Textured Porous Media Muhammad Naveed (1), Shoichiro Hamamoto (1), Ken Kawamoto (1,2), Toshihiro Sakaki (3), Per Moldrup (4), and Toshiko Komatsu (1,2) (1) Graduate School of Science and Engineering, Saitama University, Saitama, Japan (2) Institute of Environmental Science and Technology, Saitama University, Saitama, Japan (3) Center for Experimental Study of Subsurface Environmental Processes, Colorado School of Mines, Golden, CO, USA (4) Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Aalborg, Denmark

NASA Astrophysics Data System (ADS)

Naveed, M.; Kawamoto, K.; Hamamoto, S.; Sakaki, T.; Moldrup, P.; Komatsu, T.

2010-12-01

The transport and fate of gases in the soil are governed by gas advection, diffusion and dispersion phenomena. Among three gas transport phenomena, gas dispersion is least understood. Main objective of this study is to investigate the gas dispersion phenomena, emphasising on the effect of moisture content, sand particle shape, particle size, particle size distribution, and scale dependency on gas dispersion. One dimensional laboratory column experiments, in an apparatus consisting of an acrylic column attached to inlet and outlet chambers (Hamamoto et al., SSAJ, 2009), were conducted for the measurements of gas dispersion coefficient (DH). Various types of sands (Narita and Toyoura sands from Japan, and Granusils and Accusands from United States) and glass beads with variable moisture contents were used as porous media. Shape of the sand particles were characterized in terms of sphericity and roundness. The changes in the oxygen concentration within the soil column and in the inlet and outlet chambers were monitored. In addition the air pressure at inlet and middle of the soil column was also monitored to ensure the uniform density of porous media along the column. The measured breakthrough curves were fitted with the analytical solution of the advection dispersion equation to determine dispersion coefficients. The measured dispersion coefficient (DH) showed linear increase with pore velocity (u0). Measured dispersivity (λ= DH/u0) increases with decrease in air filled porosity induced by adding moisture contents in sands. Its values varies from 0 to 3 cm on decreasing air filled porosity from 0.50 (air dry) to 0.25 (field capacity). Shape of the sand particles has no significant effect on gas dispersion. When gas dispersion phenomena was studied on different shape of the sand particles at various air filled porosities, it was found that for angular sand particles initially gas dispersivity increases more rapidly as compared to rounded sand particles and finally both attains nearly same values at field capacity. Particle size has no significant effect on gas dispersion but particle size distribution has considerable effect on it. For the same sand when a coefficient of uniformity (Uc) increases from 1 to 4, gas dispersivity increases by 1.5 times. Gas dispersion coefficient was measured with two different sized columns and it was found that there is no effect of diameter and length of the column on gas dispersion for sandy soils. Therefore it can be concluded that only air filled porosity and particle size distribution should be considered for modeling the gas dispersivity in porous media.

Brain shape in human microcephalics and Homo floresiensis.

PubMed

Falk, Dean; Hildebolt, Charles; Smith, Kirk; Morwood, M J; Sutikna, Thomas; Jatmiko; Saptomo, E Wayhu; Imhof, Herwig; Seidler, Horst; Prior, Fred

2007-02-13

Because the cranial capacity of LB1 (Homo floresiensis) is only 417 cm(3), some workers propose that it represents a microcephalic Homo sapiens rather than a new species. This hypothesis is difficult to assess, however, without a clear understanding of how brain shape of microcephalics compares with that of normal humans. We compare three-dimensional computed tomographic reconstructions of the internal braincases (virtual endocasts that reproduce details of external brain morphology, including cranial capacities and shape) from a sample of 9 microcephalic humans and 10 normal humans. Discriminant and canonical analyses are used to identify two variables that classify normal and microcephalic humans with 100% success. The classification functions classify the virtual endocast from LB1 with normal humans rather than microcephalics. On the other hand, our classification functions classify a pathological H. sapiens specimen that, like LB1, represents an approximately 3-foot-tall adult female and an adult Basuto microcephalic woman that is alleged to have an endocast similar to LB1's with the microcephalic humans. Although microcephaly is genetically and clinically variable, virtual endocasts from our highly heterogeneous sample share similarities in protruding and proportionately large cerebella and relatively narrow, flattened orbital surfaces compared with normal humans. These findings have relevance for hypotheses regarding the genetic substrates of hominin brain evolution and may have medical diagnostic value. Despite LB1's having brain shape features that sort it with normal humans rather than microcephalics, other shape features and its small brain size are consistent with its assignment to a separate species.

Human Facial Shape and Size Heritability and Genetic Correlations.

PubMed

Cole, Joanne B; Manyama, Mange; Larson, Jacinda R; Liberton, Denise K; Ferrara, Tracey M; Riccardi, Sheri L; Li, Mao; Mio, Washington; Klein, Ophir D; Santorico, Stephanie A; Hallgrímsson, Benedikt; Spritz, Richard A

2017-02-01

The human face is an array of variable physical features that together make each of us unique and distinguishable. Striking familial facial similarities underscore a genetic component, but little is known of the genes that underlie facial shape differences. Numerous studies have estimated facial shape heritability using various methods. Here, we used advanced three-dimensional imaging technology and quantitative human genetics analysis to estimate narrow-sense heritability, heritability explained by common genetic variation, and pairwise genetic correlations of 38 measures of facial shape and size in normal African Bantu children from Tanzania. Specifically, we fit a linear mixed model of genetic relatedness between close and distant relatives to jointly estimate variance components that correspond to heritability explained by genome-wide common genetic variation and variance explained by uncaptured genetic variation, the sum representing total narrow-sense heritability. Our significant estimates for narrow-sense heritability of specific facial traits range from 28 to 67%, with horizontal measures being slightly more heritable than vertical or depth measures. Furthermore, for over half of facial traits, >90% of narrow-sense heritability can be explained by common genetic variation. We also find high absolute genetic correlation between most traits, indicating large overlap in underlying genetic loci. Not surprisingly, traits measured in the same physical orientation (i.e., both horizontal or both vertical) have high positive genetic correlations, whereas traits in opposite orientations have high negative correlations. The complex genetic architecture of facial shape informs our understanding of the intricate relationships among different facial features as well as overall facial development. Copyright © 2017 by the Genetics Society of America.

Deconstructing cartilage shape and size into contributions from embryogenesis, metamorphosis, and tadpole and frog growth.

PubMed

Rose, Christopher S; Murawinski, Danny; Horne, Virginia

2015-06-01

Understanding skeletal diversification involves knowing not only how skeletal rudiments are shaped embryonically, but also how skeletal shape changes throughout life. The pharyngeal arch (PA) skeleton of metamorphosing amphibians persists largely as cartilage and undergoes two phases of development (embryogenesis and metamorphosis) and two phases of growth (larval and post-metamorphic). Though embryogenesis and metamorphosis produce species-specific features of PA cartilage shape, the extents to which shape and size change during growth and metamorphosis remain unaddressed. This study uses allometric equations and thin-plate spline, relative warp and elliptic Fourier analyses to describe shape and size trajectories for the ventral PA cartilages of the frog Xenopus laevis in tadpole and frog growth and metamorphosis. Cartilage sizes scale negatively with body size in both growth phases and cartilage shapes scale isometrically or close to it. This implies that most species-specific aspects of cartilage shape arise in embryogenesis and metamorphosis. Contributions from growth are limited to minor changes in lower jaw (LJ) curvature that produce relative gape narrowing and widening in tadpoles and frogs, respectively, and most cartilages becoming relatively thinner. Metamorphosis involves previously unreported decreases in cartilage size as well as changes in cartilage shape. The LJ becomes slightly longer, narrower and more curved, and the adult ceratohyal emerges from deep within the resorbing tadpole ceratohyal. This contrast in shape and size changes suggests a fundamental difference in the underlying cellular pathways. The observation that variation in PA cartilage shape decreases with tadpole growth supports the hypothesis that isometric growth is required for the metamorphic remodeling of PA cartilages. It also supports the existence of shape-regulating mechanisms that are specific to PA cartilages and that resist local adaptation and phenotypic plasticity. © 2015 Anatomical Society.

Deconstructing cartilage shape and size into contributions from embryogenesis, metamorphosis, and tadpole and frog growth

PubMed Central

Rose, Christopher S; Murawinski, Danny; Horne, Virginia

2015-01-01

Understanding skeletal diversification involves knowing not only how skeletal rudiments are shaped embryonically, but also how skeletal shape changes throughout life. The pharyngeal arch (PA) skeleton of metamorphosing amphibians persists largely as cartilage and undergoes two phases of development (embryogenesis and metamorphosis) and two phases of growth (larval and post-metamorphic). Though embryogenesis and metamorphosis produce species-specific features of PA cartilage shape, the extents to which shape and size change during growth and metamorphosis remain unaddressed. This study uses allometric equations and thin-plate spline, relative warp and elliptic Fourier analyses to describe shape and size trajectories for the ventral PA cartilages of the frog Xenopus laevis in tadpole and frog growth and metamorphosis. Cartilage sizes scale negatively with body size in both growth phases and cartilage shapes scale isometrically or close to it. This implies that most species-specific aspects of cartilage shape arise in embryogenesis and metamorphosis. Contributions from growth are limited to minor changes in lower jaw (LJ) curvature that produce relative gape narrowing and widening in tadpoles and frogs, respectively, and most cartilages becoming relatively thinner. Metamorphosis involves previously unreported decreases in cartilage size as well as changes in cartilage shape. The LJ becomes slightly longer, narrower and more curved, and the adult ceratohyal emerges from deep within the resorbing tadpole ceratohyal. This contrast in shape and size changes suggests a fundamental difference in the underlying cellular pathways. The observation that variation in PA cartilage shape decreases with tadpole growth supports the hypothesis that isometric growth is required for the metamorphic remodeling of PA cartilages. It also supports the existence of shape-regulating mechanisms that are specific to PA cartilages and that resist local adaptation and phenotypic plasticity. PMID:25913729

A statistical test of unbiased evolution of body size in birds.

PubMed

Bokma, Folmer

2002-12-01

Of the approximately 9500 bird species, the vast majority is small-bodied. That is a general feature of evolutionary lineages, also observed for instance in mammals and plants. The avian interspecific body size distribution is right-skewed even on a logarithmic scale. That has previously been interpreted as evidence that body size evolution has been biased. However, a procedure to test for unbiased evolution from the shape of body size distributions was lacking. In the present paper unbiased body size evolution is defined precisely, and a statistical test is developed based on Monte Carlo simulation of unbiased evolution. Application of the test to birds suggests that it is highly unlikely that avian body size evolution has been unbiased as defined. Several possible explanations for this result are discussed. A plausible explanation is that the general model of unbiased evolution assumes that population size and generation time do not affect the evolutionary variability of body size; that is, that micro- and macroevolution are decoupled, which theory suggests is not likely to be the case.

The Remarkable Change in Euro-American Cranial Shape and Size.

PubMed

Jantz, Richard L; Jantz, Lee Meadows

2016-01-01

Secular changes in stature, weight, or other components of the body that can be obtained from historical records have been extensively studied. Cranial change has been central to anthropology for more than a century, but the focus has normally been on change measured in centuries or millennia. Cranial change measured in decades, normally considered to result from plastic response to the environment, has been less studied. This article reports on change in cranial vault dimensions in white Americans. Variables were glabello-occipital length (GOL), basion-bregma height (BBH), basion-nasion length (BNL), maximum cranial breadth (XCB), and biauricular breadth (AUB). Cranial size was calculated as the geometric mean of these variables, and shape dimensions were calculated as described by Darroch and Mosimann ( 1985 ). Cranial module and cranial capacity were also calculated. Samples consisted of 1,112 males and 668 females complete for those variables. Samples were organized into 10-year birth cohorts, with birth years ranging from 1820 to 1990. One-way ANOVA was used to test for variation among cohorts. The pattern of secular change was examined graphically and was compared with quality-of-life and environmental indicators, including stature, infant mortality, calories per person, and relative number of immigrants. All variables showed significant secular change, but BBH, XCB, and BNL responded most strongly. Over the past 170 years, crania became relatively higher, narrower, and larger with longer cranial bases. Both sexes changed, but female change was less pronounced than male change. The cranial variables tracked secular changes in stature, most prominently BNL. The highest correlation between a cranial variable and quality-of-life indicator was BBH and infant mortality. We are not able to identify specific causes of secular changes in cranial morphology. However, given that modern Americans have introduced themselves into a novel environment never before experienced by human populations, we consider it unlikely that it is pure plasticity. In addition to possible plastic responses, it is likely that selection, acting through the dramatic changes in infant mortality, is also involved.

Vertical uniformity of cells and nuclei in epithelial monolayers.

PubMed

Neelam, Srujana; Hayes, Peter Robert; Zhang, Qiao; Dickinson, Richard B; Lele, Tanmay P

2016-01-22

Morphological variability in cytoskeletal organization, organelle position and cell boundaries is a common feature of cultured cells. Remarkable uniformity and reproducibility in structure can be accomplished by providing cells with defined geometric cues. Cells in tissues can also self-organize in the absence of directing extracellular cues; however the mechanical principles for such self-organization are not understood. We report that unlike horizontal shapes, the vertical shapes of the cell and nucleus in the z-dimension are uniform in cells in cultured monolayers compared to isolated cells. Apical surfaces of cells and their nuclei in monolayers were flat and heights were uniform. In contrast, isolated cells, or cells with disrupted cell-cell adhesions had nuclei with curved apical surfaces and variable heights. Isolated cells cultured within micron-sized square wells displayed flat cell and nuclear shapes similar to cells in monolayers. Local disruption of nuclear-cytoskeletal linkages resulted in spatial variation in vertical uniformity. These results suggest that competition between cell-cell pulling forces that expand and shorten the vertical cell cross-section, thereby widening and flattening the nucleus, and the resistance of the nucleus to further flattening results in uniform cell and nuclear cross-sections. Our results reveal the mechanical principles of self-organized vertical uniformity in cell monolayers.

The grain size dependency of vesicular particle shapes strongly affects the drag of particles. First results from microtomography investigations of Campi Flegrei fallout deposits

NASA Astrophysics Data System (ADS)

Mele, Daniela; Dioguardi, Fabio

2018-03-01

Acknowledging the grain size dependency of shape is important in volcanology, in particular when dealing with tephra produced and emplaced during and after explosive volcanic eruptions. A systematic measurement of the tridimensional shape of vesicular pyroclasts of Campi Flegrei fallout deposits (Agnano-Monte Spina, Astroni 6 and Averno 2 eruptions) varying in size from 8.00 to 0.016 mm has been carried out by means of X-Ray Microtomography. Data show that particle shape changes with size, especially for juvenile vesicular clasts, since it is dependent on the distribution and size of vesicles that contour the external clast outline. Two drag laws that include sphericity in the formula were used for estimating the dependency of settling velocity on shape. Results demonstrate that it is not appropriate to assume a size-independent shape for vesicular particles, in contrast with the approach commonly employed when simulating the ash dispersion in the atmosphere.

Identification of different shapes, colors and sizes of standard oral dosage forms in diabetes type 2 patients-A pilot study.

PubMed

Stegemann, Sven; Riedl, Regina; Sourij, Harald

2017-01-30

The clear identification of drug products by the patients is essential for a safe and effective medication management. In order to understand the impact of shape, size and color on medication identification a study was performed in subjects with type 2 diabetes mellitus (T2D). Ten model drugs differentiated by shape, size and color were evaluated using a mixed method of medication schedule preparation by the participants followed by a semi-structured interview. Detection times were fastest for the large round tablet shape and the bi-chromatic forms. Larger size was easier to identify than the smaller sizes except for the bi-chromatic forms. The shape was the major source of errors, followed by the size and the color dimension. The results from this study suggests that color as a single dimension are perceived more effectively by subjects with T2D compared to shape and size, which requires a more demanding processing of three dimension and is dependent on the perspective. Copyright © 2016 Elsevier B.V. All rights reserved.

Is the number and size of scales in Liolaemus lizards driven by climate?

PubMed

José Tulli, María; Cruz, Félix B

2018-05-03

Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they occur. To buffer these fluctuations, ectotherms use different strategies, including the integument, which is a barrier that minimizes temperature exchange between the inner body and the surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape and texture, and its main function is protection, water loss avoidance and thermoregulation. The size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it has also been observed that in some groups of Iguanian lizards could be related to phylogeny. Thus, here, we studied the area and number of scales (dorsal and ventral) of 61 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate, and found that the number and size of scales are related to climatic variables, such as temperature and geographical variables as altitude. The evolutionary process that better explained how these morphological variables evolved was the Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry, whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is thus under less pressure to change in response to alterations in external conditions. It is possible that scale ornamentation such as keels and granulosity may bring some more information in this regard. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Characterization and Reconstruction of Nanolipoprotein Particles (Nlps) by Cryo-EM and Image Reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pesavento, J B; Morgan, D; Bermingham, R

Nanolipoprotein particles (NLPs) are small 10-20 nm diameter assemblies of apolipoproteins and lipids. At Lawrence Livermore National Laboratory (LLNL), they have constructed multiple variants of these assemblies. NLPs have been generated from a variety of lipoproteins, including apolipoprotein Al, apolipophorin III, apolipoprotein E4 22K, and MSP1T2 (nanodisc, Inc.). Lipids used included DMPC (bulk of the bilayer material), DMPE (in various amounts), and DPPC. NLPs were made in either the absence or presence of the detergent cholate. They have collected electron microscopy data as a part of the characterization component of this research. Although purified by size exclusion chromatography (SEC), samplesmore » are somewhat heterogeneous when analyzed at the nanoscale by negative stained cryo-EM. Images reveal a broad range of shape heterogeneity, suggesting variability in conformational flexibility, in fact, modeling studies point to dynamics of inter-helical loop regions within apolipoproteins as being a possible source for observed variation in NLP size. Initial attempts at three-dimensional reconstructions have proven to be challenging due to this size and shape disparity. They are pursuing a strategy of computational size exclusion to group particles into subpopulations based on average particle diameter. They show here results from their ongoing efforts at statistically and computationally subdividing NLP populations to realize greater homogeneity and then generate 3D reconstructions.« less

An Energy Absorber for the International Space Station

NASA Technical Reports Server (NTRS)

Wilkes, Bob; Laurence, Lora

2000-01-01

The energy absorber described herein is similar in size and shape to an automotive shock absorber, requiring a constant, high load to compress over the stroke, and self-resetting with a small load. The differences in these loads over the stroke represent the energy absorbed by the device, which is dissipated as friction. This paper describes the evolution of the energy absorber, presents the results of testing performed, and shows the sensitivity of this device to several key design variables.

Bioavailability of Lead in Small Arms Range Soils

DTIC Science & Technology

2007-09-01

minerals, and may also exist inside particles of inert matrix such as rock or slag of variable size, shape, and association; these chemical and...Abbreviations: Fe=iron, Pb=lead, Cu=copper, Ti=titanium, Zn= zinc , Sb=antimony, Rb=rubidium, Zr=zirconium, As=arsenic. Values are mean of three...20 30 40 50 60 70 80 FeOOH Cerussite Organic Phosphate PbMO PbAsO MnOOH Anglesite PbOOH PbCl4 Slag FeSO4 PbO Frequency of Occurrence Relative Pb

Electrostatics effects in granular materials

NASA Astrophysics Data System (ADS)

Sarkar, Saurabh; Chaudhuri, Bodhisattwa

2013-06-01

This purpose of this study is to investigate the role of physiochemical properties and operational conditions in determining the electrostatic interactions between two species on a surface under typical industrial conditions. The variables considered for the study were particle type, particle size and shape, loading mass, surface type, angle of inclination of chute, nature and concentration of additive. Triboelectrification of simple and binary mixtures in a simple hopper and chute geometry was observed to be strongly linked to work function and moisture content of the powdered material.

Variation in Craniomandibular Morphology and Sexual Dimorphism in Pantherines and the Sabercat Smilodon fatalis

PubMed Central

Christiansen, Per; Harris, John M.

2012-01-01

Sexual dimorphism is widespread among carnivorans, and has been an important evolutionary factor in social ecology. However, its presence in sabertoothed felids remains contentious. Here we present a comprehensive analysis of extant Panthera and the sabertoothed felid Smilodon fatalis. S. fatalis has been reported to show little or no sexual dimorphism but to have been intraspecifically variable in skull morphology. We found that large and small specimens of S. fatalis could be assigned to male and female sexes with similar degrees of confidence as Panthera based on craniomandibular shape. P. uncia is much less craniomandibularly variable and has low levels of sexual size-dimorphism. Shape variation in S. fatalis probably reflects sexual differences. Craniomandibular size-dimorphism is lower in S. fatalis than in Panthera except P. uncia. Sexual dimorphism in felids is related to more than overall size, and S. fatalis and the four large Panthera species show marked and similar craniomandibular and dental morphometric sexual dimorphism, whereas morphometric dimorphism in P. uncia is less. Many morphometric-sexually dimorphic characters in Panthera and Smilodon are related to bite strength and presumably to killing ecology. This suggests that morphometric sexual dimorphism is an evolutionary adaptation to intraspecific resource partitioning, since large males with thicker upper canines and stronger bite forces would be able to hunt larger prey than females, which is corroborated by feeding ecology in P. leo. Sexual dimorphism indicates that S. fatalis could have been social, but it is unlikely that it lived in fusion-fission units dominated by one or a few males, as in sub-Saharan populations of P. leo. Instead, S. fatalis could have been solitary and polygynous, as most extant felids, or it may have lived in unisexual groups, as is common in P. leo persica. PMID:23110232

Variability Matters: New Insights into Mechanics of River Avulsions on Deltas and Their Deposits

NASA Astrophysics Data System (ADS)

Ganti, V.

2015-12-01

River deltas are highly dynamic, often fan-shaped depositional systems that form when rivers drain into a standing body of water. They host over a half billion people and are currently under threat of drowning and destruction by relative sea-level rise, subsidence, and anthropogenic interference. Deltas often develop planform fan shapes through avulsions, whereby major river channel shifts occur via "channel jumping" about a spatial node, thus determining their fundamental length scale. Emerging theories suggest that the size of delta lobes is set by backwater hydrodynamics; however, these ideas are difficult to test on natural deltas, which evolve on centennial to millennial timescales. In this presentation, I will show results from the first laboratory delta built through successive deposition of lobes that maintain a constant size that scales with backwater hydrodynamics. The characteristic size of deltas emerges because of a preferential avulsion node that remains fixed spatially relative to the prograding shoreline, and is a consequence of multiple river floods that produce persistent morphodynamic river-bed adjustment within the backwater zone. Moreover, river floods cause erosion in the lowermost reaches of the alluvial river near their coastline, which may leave erosional boundaries in the sedimentary record that may appear similar to those previously interpreted to be a result of relative sea-level fall. I will discuss the implications of these findings in the context of sustainability management of deltas, decoding their stratigraphic record, and identifying ancient standing bodies of water on other planets such as Mars. Finally, I will place this delta study in a broader context of recent work that highlights the importance of understanding and quantifying variability in sedimentology and geomorphology.

Sperm kinematic, head morphometric and kinetic-morphometric subpopulations in the blue fox (Alopex lagopus).

PubMed

Soler, Carles; Contell, Jesús; Bori, Lorena; Sancho, María; García-Molina, Almudena; Valverde, Anthony; Segarvall, Jan

2017-01-01

This work provides information on the blue fox ejaculated sperm quality needed for seminal dose calculations. Twenty semen samples, obtained by masturbation, were analyzed for kinematic and morphometric parameters by using CASA-Mot and CASA-Morph system and principal component (PC) analysis. For motility, eight kinematic parameters were evaluated, which were reduced to PC1, related to linear variables, and PC2, related to oscillatory movement. The whole population was divided into three independent subpopulations: SP1, fast cells with linear movement; SP2, slow cells and nonoscillatory motility; and SP3, medium speed cells and oscillatory movement. In almost all cases, the subpopulation distribution by animal was significantly different. Head morphology analysis generated four size and four shape parameters, which were reduced to PC1, related to size, and PC2, related to shape of the cells. Three morphometric subpopulations existed: SP1: large oval cells; SP2: medium size elongated cells; and SP3: small and short cells. The subpopulation distribution differed between animals. Combining the kinematic and morphometric datasets produced PC1, related to morphometric parameters, and PC2, related to kinematics, which generated four sperm subpopulations - SP1: high oscillatory motility, large and short heads; SP2: medium velocity with small and short heads; SP3: slow motion small and elongated cells; and SP4: high linear speed and large elongated cells. Subpopulation distribution was different in all animals. The establishment of sperm subpopulations from kinematic, morphometric, and combined variables not only improves the well-defined fox semen characteristics and offers a good conceptual basis for fertility and sperm preservation techniques in this species, but also opens the door to use this approach in other species, included humans.

Sperm kinematic, head morphometric and kinetic-morphometric subpopulations in the blue fox (Alopex lagopus)

PubMed Central

Soler, Carles; Contell, Jesús; Bori, Lorena; Sancho, María; García-Molina, Almudena; Valverde, Anthony; Segarvall, Jan

2017-01-01

This work provides information on the blue fox ejaculated sperm quality needed for seminal dose calculations. Twenty semen samples, obtained by masturbation, were analyzed for kinematic and morphometric parameters by using CASA-Mot and CASA-Morph system and principal component (PC) analysis. For motility, eight kinematic parameters were evaluated, which were reduced to PC1, related to linear variables, and PC2, related to oscillatory movement. The whole population was divided into three independent subpopulations: SP1, fast cells with linear movement; SP2, slow cells and nonoscillatory motility; and SP3, medium speed cells and oscillatory movement. In almost all cases, the subpopulation distribution by animal was significantly different. Head morphology analysis generated four size and four shape parameters, which were reduced to PC1, related to size, and PC2, related to shape of the cells. Three morphometric subpopulations existed: SP1: large oval cells; SP2: medium size elongated cells; and SP3: small and short cells. The subpopulation distribution differed between animals. Combining the kinematic and morphometric datasets produced PC1, related to morphometric parameters, and PC2, related to kinematics, which generated four sperm subpopulations – SP1: high oscillatory motility, large and short heads; SP2: medium velocity with small and short heads; SP3: slow motion small and elongated cells; and SP4: high linear speed and large elongated cells. Subpopulation distribution was different in all animals. The establishment of sperm subpopulations from kinematic, morphometric, and combined variables not only improves the well-defined fox semen characteristics and offers a good conceptual basis for fertility and sperm preservation techniques in this species, but also opens the door to use this approach in other species, included humans. PMID:27751987

Body size and allometric variation in facial shape in children.

PubMed

Larson, Jacinda R; Manyama, Mange F; Cole, Joanne B; Gonzalez, Paula N; Percival, Christopher J; Liberton, Denise K; Ferrara, Tracey M; Riccardi, Sheri L; Kimwaga, Emmanuel A; Mathayo, Joshua; Spitzmacher, Jared A; Rolian, Campbell; Jamniczky, Heather A; Weinberg, Seth M; Roseman, Charles C; Klein, Ophir; Lukowiak, Ken; Spritz, Richard A; Hallgrimsson, Benedikt

2018-02-01

Morphological integration, or the tendency for covariation, is commonly seen in complex traits such as the human face. The effects of growth on shape, or allometry, represent a ubiquitous but poorly understood axis of integration. We address the question of to what extent age and measures of size converge on a single pattern of allometry for human facial shape. Our study is based on two large cross-sectional cohorts of children, one from Tanzania and the other from the United States (N = 7,173). We employ 3D facial imaging and geometric morphometrics to relate facial shape to age and anthropometric measures. The two populations differ significantly in facial shape, but the magnitude of this difference is small relative to the variation within each group. Allometric variation for facial shape is similar in both populations, representing a small but significant proportion of total variation in facial shape. Different measures of size are associated with overlapping but statistically distinct aspects of shape variation. Only half of the size-related variation in facial shape can be explained by the first principal component of four size measures and age while the remainder associates distinctly with individual measures. Allometric variation in the human face is complex and should not be regarded as a singular effect. This finding has important implications for how size is treated in studies of human facial shape and for the developmental basis for allometric variation more generally. © 2017 Wiley Periodicals, Inc.

Determination of macular hole size in relation to individual variabilities of fovea morphology.

PubMed

Shin, J Y; Chu, Y K; Hong, Y T; Kwon, O W; Byeon, S H

2015-08-01

To determine the preoperative anatomic factors in macular holes and their correlation to hole closure. Forty-six eyes with consecutive unilateral macular hole who had undergone surgery and followed up for at least 6 months were enrolled. Optical coherence tomography images and best-corrected visual acuity (BCVA) within 2 weeks prior to operation and 6 months after surgery were analyzed. The maximal hole dimension, foveal degeneration factors (inner nuclear layer cysts, outer segment (OS) shortening) and the widest foveolar floor size of the fellow eyes were measured. For overcoming preoperative individual variability of foveal morphology, an 'adjusted' hole size parameter (the ratio between the hole size and the fellow eye foveolar floor size) was used based on the fact that both eyes were morphologically symmetrical. Mean preoperative BCVA (logMAR) was 1.03±0.43 and the mean postoperative BCVA was 0.50±0.38 at 6 months. Preoperative BCVA is significantly associated with postoperative BCVA (P=0.0002). The average hole diameter was 448.9±196.8 μm and the average fellow eye foveolar floor size was 461.3±128.4 μm. There was a correlation between hole diameter and the size of the fellow eye foveolar floor (Pearson's coefficient=0.608, P<0.0001). The adjusted hole size parameter was 0.979±0.358 (0.761-2.336), which was a strong predictor for both anatomic (P=0.0281) and visual (P=0.0016) outcome. When determining the extent of preoperative hole size, we have to take into consideration the foveal morphologic variations among individuals. Hole size may be related to the original foveal shape, especially in relation to the centrifugal retraction of the foveal tissues.

Evaluation of the chondral modeling theory using fe-simulation and numeric shape optimization

PubMed Central

Plochocki, Jeffrey H; Ward, Carol V; Smith, Douglas E

2009-01-01

The chondral modeling theory proposes that hydrostatic pressure within articular cartilage regulates joint size, shape, and congruence through regional variations in rates of tissue proliferation.The purpose of this study is to develop a computational model using a nonlinear two-dimensional finite element analysis in conjunction with numeric shape optimization to evaluate the chondral modeling theory. The model employed in this analysis is generated from an MR image of the medial portion of the tibiofemoral joint in a subadult male. Stress-regulated morphological changes are simulated until skeletal maturity and evaluated against the chondral modeling theory. The computed results are found to support the chondral modeling theory. The shape-optimized model exhibits increased joint congruence, broader stress distributions in articular cartilage, and a relative decrease in joint diameter. The results for the computational model correspond well with experimental data and provide valuable insights into the mechanical determinants of joint growth. The model also provides a crucial first step toward developing a comprehensive model that can be employed to test the influence of mechanical variables on joint conformation. PMID:19438771

Body shape convergence driven by small size optimum in marine angelfishes.

PubMed

Frédérich, Bruno; Santini, Francesco; Konow, Nicolai; Schnitzler, Joseph; Lecchini, David; Alfaro, Michael E

2017-06-01

Convergent evolution of small body size occurs across many vertebrate clades and may reflect an evolutionary response to shared selective pressures. However it remains unclear if other aspects of phenotype undergo convergent evolution in miniaturized lineages. Here we present a comparative analysis of body size and shape evolution in marine angelfishes (Pomacanthidae), a reef fish family characterized by repeated transitions to small body size. We ask if lineages that evolve small sizes show convergent evolution in body shape. Our results reveal that angelfish lineages evolved three different stable size optima with one corresponding to the group of pygmy angelfishes ( Centropyge ). Then, we test if the observed shifts in body size are associated with changes to new adaptive peaks in shape. Our data suggest that independent evolution to small size optima have induced repeated convergence upon deeper body and steeper head profile in Centropyge These traits may favour manoeuvrability and visual awareness in these cryptic species living among corals, illustrating that functional demands on small size may be related to habitat specialization and predator avoidance. The absence of shape convergence in large marine angelfishes also suggests that more severe requirements exist for small than for large size optima. © 2017 The Author(s).

Shape Comparison Between 0.4–2.0 and 20–60 lm Cement Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzer, L.; Flatt, R; Erdogan, S

Portland cement powder, ground from much larger clinker particles, has a particle size distribution from about 0.1 to 100 {micro}m. An important question is then: does particle shape depend on particle size? For the same cement, X-ray computed tomography has been used to examine the 3-D shape of particles in the 20-60 {micro}m sieve range, and focused ion beam nanotomography has been used to examine the 3-D shape of cement particles found in the 0.4-2.0 {micro}m sieve range. By comparing various kinds of computed particle shape data for each size class, the conclusion is made that, within experimental uncertainty, bothmore » size classes are prolate, but the smaller size class particles, 0.4-2.0 {micro}m, tend to be somewhat more prolate than the 20-60 {micro}m size class. The practical effect of this shape difference on the set-point was assessed using the Virtual Cement and Concrete Testing Laboratory to simulate the hydration of five cement powders. Results indicate that nonspherical aspect ratio is more important in determining the set-point than are the actual shape details.« less

Extended Fitts' model of pointing time in eye-gaze input system - Incorporating effects of target shape and movement direction into modeling.

PubMed

Murata, Atsuo; Fukunaga, Daichi

2018-04-01

This study attempted to investigate the effects of the target shape and the movement direction on the pointing time using an eye-gaze input system and extend Fitts' model so that these factors are incorporated into the model and the predictive power of Fitts' model is enhanced. The target shape, the target size, the movement distance, and the direction of target presentation were set as within-subject experimental variables. The target shape included: a circle, and rectangles with an aspect ratio of 1:1, 1:2, 1:3, and 1:4. The movement direction included eight directions: upper, lower, left, right, upper left, upper right, lower left, and lower right. On the basis of the data for identifying the effects of the target shape and the movement direction on the pointing time, an attempt was made to develop a generalized and extended Fitts' model that took into account the movement direction and the target shape. As a result, the generalized and extended model was found to fit better to the experimental data, and be more effective for predicting the pointing time for a variety of human-computer interaction (HCI) task using an eye-gaze input system. Copyright © 2017. Published by Elsevier Ltd.

Surface characteristics of isopod digestive gland epithelium studied by SEM.

PubMed

Millaku, Agron; Leser, Vladka; Drobne, Damjana; Godec, Matjaz; Torkar, Matjaz; Jenko, Monika; Milani, Marziale; Tatti, Francesco

2010-05-01

The structure of the digestive gland epithelium of a terrestrial isopod Porcellio scaber has been investigated by conventional scanning electron microscopy (SEM), focused ion beam-scanning electron microscopy (FIB/SEM), and light microscopy in order to provide evidence on morphology of the gland epithelial surface in animals from a stock culture. We investigated the shape of cells, extrusion of lipid droplets, shape and distribution of microvilli, and the presence of bacteria on the cell surface. A total of 22 animals were investigated and we found some variability in the appearance of the gland epithelial surface. Seventeen of the animals had dome-shaped digestive gland "normal" epithelial cells, which were densely and homogeneously covered by microvilli and varying proportions of which extruded lipid droplets. On the surface of microvilli we routinely observed sparsely distributed bacteria of different shapes. Five of the 22 animals had "abnormal" epithelial cells with a significantly altered shape. In three of these animals, the cells were much smaller, partly or completely flat or sometimes pyramid-like. A thick layer of bacteria was detected on the microvillous border, and in places, the shape and size of microvilli were altered. In two animals, hypertrophic cells containing large vacuoles were observed indicating a characteristic intracellular infection. The potential of SEM in morphological investigations of epithelial surfaces is discussed.

The decomposition of deformation: New metrics to enhance shape analysis in medical imaging.

PubMed

Varano, Valerio; Piras, Paolo; Gabriele, Stefano; Teresi, Luciano; Nardinocchi, Paola; Dryden, Ian L; Torromeo, Concetta; Puddu, Paolo E

2018-05-01

In landmarks-based Shape Analysis size is measured, in most cases, with Centroid Size. Changes in shape are decomposed in affine and non affine components. Furthermore the non affine component can be in turn decomposed in a series of local deformations (partial warps). If the extent of deformation between two shapes is small, the difference between Centroid Size and m-Volume increment is barely appreciable. In medical imaging applied to soft tissues bodies can undergo very large deformations, involving large changes in size. The cardiac example, analyzed in the present paper, shows changes in m-Volume that can reach the 60%. We show here that standard Geometric Morphometrics tools (landmarks, Thin Plate Spline, and related decomposition of the deformation) can be generalized to better describe the very large deformations of biological tissues, without losing a synthetic description. In particular, the classical decomposition of the space tangent to the shape space in affine and non affine components is enriched to include also the change in size, in order to give a complete description of the tangent space to the size-and-shape space. The proposed generalization is formulated by means of a new Riemannian metric describing the change in size as change in m-Volume rather than change in Centroid Size. This leads to a redefinition of some aspects of the Kendall's size-and-shape space without losing Kendall's original formulation. This new formulation is discussed by means of simulated examples using 2D and 3D platonic shapes as well as a real example from clinical 3D echocardiographic data. We demonstrate that our decomposition based approaches discriminate very effectively healthy subjects from patients affected by Hypertrophic Cardiomyopathy. Copyright © 2018 Elsevier B.V. All rights reserved.

An online detection system for aggregate sizes and shapes based on digital image processing

NASA Astrophysics Data System (ADS)

Yang, Jianhong; Chen, Sijia

2017-02-01

Traditional aggregate size measuring methods are time-consuming, taxing, and do not deliver online measurements. A new online detection system for determining aggregate size and shape based on a digital camera with a charge-coupled device, and subsequent digital image processing, have been developed to overcome these problems. The system captures images of aggregates while falling and flat lying. Using these data, the particle size and shape distribution can be obtained in real time. Here, we calibrate this method using standard globules. Our experiments show that the maximum particle size distribution error was only 3 wt%, while the maximum particle shape distribution error was only 2 wt% for data derived from falling aggregates, having good dispersion. In contrast, the data for flat-lying aggregates had a maximum particle size distribution error of 12 wt%, and a maximum particle shape distribution error of 10 wt%; their accuracy was clearly lower than for falling aggregates. However, they performed well for single-graded aggregates, and did not require a dispersion device. Our system is low-cost and easy to install. It can successfully achieve online detection of aggregate size and shape with good reliability, and it has great potential for aggregate quality assurance.

Gender differences in foot shape: a study of Chinese young adults.

PubMed

Hong, Youlian; Wang, Lin; Xu, Dong Qing; Li, Jing Xian

2011-06-01

One important extrinsic factor that causes foot deformity and pain in women is footwear. Women's sports shoes are designed as smaller versions of men's shoes. Based on this, the current study aims to identify foot shape in 1,236 Chinese young adult men and 1,085 Chinese young adult women. Three-dimensional foot shape data were collected through video filming. Nineteen foot shape variables were measured, including girth (4 variables), length (4 variables), width (3 variables), height (7 variables), and angle (1 variable). A comparison of foot measures within the range of the common foot length (FL) categories indicates that women showed significantly smaller values of foot measures in width, height, and girth than men. Three foot types were classified, and distributions of different foot shapes within the same FL were found between women and men. Foot width, medial ball length, ball angle, and instep height showed significant differences among foot types in the same FL for both genders. There were differences in the foot shape between Chinese young women and men, which should be considered in the design of Chinese young adults' sports shoes.

Two Echinostome Species, Pegosomum bubulcum and Nephrostomum ramosum (Digenea: Echinostomatidae), from an Eastern Cattle Egret, Bubulcus ibis coromandus, in Republic of Korea

PubMed Central

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Kim, Eunju; Na, Ki-Jeong; Eom, Keeseon S.

2016-01-01

We describe 2 echinostome species recovered from an Eastern cattle egret, Bubulcus ibis coromandus, from Cheongju-si (city), Chungcheongbuk-do (province), Korea. Total 72 Pegosomum bubulcum specimens were recovered from the bile duct. They were 7,566×2,938 μm in average size and had 27 collar spines with vitelline extension from anterior 1/3 level of the esophagus to mid-level of the posterior testis as characteristic features. Total 9 specimens of Nephrostomum ramosum were recovered in the small intestines of the bird. They were ribbon-shaped, 11,378×2,124 μm in average size, and morphologically variable in some organs, i.e., the number of collar spines (47-50), the shape of ovary and testes, and the extension of vitelline follicles. These morphological variations observed in a single host indicated that these features are not critical for the classification of Nephrostomum species and thus were reconsidered taxonomically as synonym of N. ramosum. This study is the first report documenting and describing both flukes and their associated genera in Korea. PMID:27658601

Two Echinostome Species, Pegosomum bubulcum and Nephrostomum ramosum (Digenea: Echinostomatidae), from an Eastern Cattle Egret, Bubulcus ibis coromandus, in Republic of Korea.

PubMed

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Kim, Eunju; Na, Ki-Jeong; Eom, Keeseon S

2016-08-01

We describe 2 echinostome species recovered from an Eastern cattle egret, Bubulcus ibis coromandus, from Cheongju-si (city), Chungcheongbuk-do (province), Korea. Total 72 Pegosomum bubulcum specimens were recovered from the bile duct. They were 7,566×2,938 μm in average size and had 27 collar spines with vitelline extension from anterior 1/3 level of the esophagus to mid-level of the posterior testis as characteristic features. Total 9 specimens of Nephrostomum ramosum were recovered in the small intestines of the bird. They were ribbon-shaped, 11,378×2,124 μm in average size, and morphologically variable in some organs, i.e., the number of collar spines (47-50), the shape of ovary and testes, and the extension of vitelline follicles. These morphological variations observed in a single host indicated that these features are not critical for the classification of Nephrostomum species and thus were reconsidered taxonomically as synonym of N. ramosum. This study is the first report documenting and describing both flukes and their associated genera in Korea.

Recent advances in understanding nuclear size and shape

PubMed Central

Mukherjee, Richik N.; Chen, Pan; Levy, Daniel L.

2016-01-01

ABSTRACT Size and shape are important aspects of nuclear structure. While normal cells maintain nuclear size within a defined range, altered nuclear size and shape are associated with a variety of diseases. It is unknown if altered nuclear morphology contributes to pathology, and answering this question requires a better understanding of the mechanisms that control nuclear size and shape. In this review, we discuss recent advances in our understanding of the mechanisms that regulate nuclear morphology, focusing on nucleocytoplasmic transport, nuclear lamins, the endoplasmic reticulum, the cell cycle, and potential links between nuclear size and size regulation of other organelles. We then discuss the functional significance of nuclear morphology in the context of early embryonic development. Looking toward the future, we review new experimental approaches that promise to provide new insights into mechanisms of nuclear size control, in particular microfluidic-based technologies, and discuss how altered nuclear morphology might impact chromatin organization and physiology of diseased cells. PMID:26963026

Acoustic modeling and eigenanalysis of coupled rooms with a transparent coupling aperture of variable size

NASA Astrophysics Data System (ADS)

Shi, Shuangxia; Jin, Guoyong; Xiao, Bin; Liu, Zhigang

2018-04-01

This paper is concerned with the modeling and acoustic eigenanalysis of coupled spaces with a coupling aperture of variable size. A modeling method for this problem is developed based on the energy principle in combination with a 3D modified Fourier cosine series approach. Under this theoretical framework, the energy exchange property and acoustically transparent characteristics of the opening are taken into account via the inflow and outflow sound powers through the opening without any assumptions. The sound pressure in the subrooms is constructed in the form of the three-dimensional modified Fourier series with several auxiliary functions introduced to ensure the uniform convergence of the solution over the entire solution domain. The accuracy of the natural frequencies and mode shapes of three exemplary coupled rooms systems is verified against numerical data obtained by finite element method, with good agreement achieved. The present method offers a unified procedure for a variety of cases because the modification of any parameter from one case to another, such as the size and location of the coupling aperture, is as simple as modifying the material properties, requiring no changes to the solution procedures.

Geometric constraints during epithelial jamming

NASA Astrophysics Data System (ADS)

Atia, Lior; Bi, Dapeng; Sharma, Yasha; Mitchel, Jennifer A.; Gweon, Bomi; Koehler, Stephan A.; DeCamp, Stephen J.; Lan, Bo; Kim, Jae Hun; Hirsch, Rebecca; Pegoraro, Adrian F.; Lee, Kyu Ha; Starr, Jacqueline R.; Weitz, David A.; Martin, Adam C.; Park, Jin-Ah; Butler, James P.; Fredberg, Jeffrey J.

2018-06-01

As an injury heals, an embryo develops or a carcinoma spreads, epithelial cells systematically change their shape. In each of these processes cell shape is studied extensively whereas variability of shape from cell to cell is regarded most often as biological noise. But where do cell shape and its variability come from? Here we report that cell shape and shape variability are mutually constrained through a relationship that is purely geometrical. That relationship is shown to govern processes as diverse as maturation of the pseudostratified bronchial epithelial layer cultured from non-asthmatic or asthmatic donors, and formation of the ventral furrow in the Drosophila embryo. Across these and other epithelial systems, shape variability collapses to a family of distributions that is common to all. That distribution, in turn, is accounted for by a mechanistic theory of cell-cell interaction, showing that cell shape becomes progressively less elongated and less variable as the layer becomes progressively more jammed. These findings suggest a connection between jamming and geometry that spans living organisms and inert jammed systems, and thus transcends system details. Although molecular events are needed for any complete theory of cell shape and cell packing, observations point to the hypothesis that jamming behaviour at larger scales of organization sets overriding geometric constraints.

MRI analysis of the size and shape of the oropharynx in chronic whiplash.

PubMed

Elliott, James; Cannata, Emma; Christensen, Eric; Demaris, Joel; Kummrow, John; Manning, Erin; Nielsen, Elizabeth; Romero, Tomas; Barnes, Clifford; Jull, Gwendolen

2008-06-01

To quantify differences in the size/shape of the oropharynx between female subjects with whiplash and controls. Retrospective cohort. A total of 113 subjects (79 whiplash, 34 controls) were included. T1-weighted MRI was used to measure 1) cross-sectional area (CSA [mm(2)]) and 2) shape ratios for the oropharynx. Reliability data were established. Whiplash subjects had significantly smaller oropharynx CSAs (P < 0.001) and shape ratios (P < 0.001) compared with healthy controls. Self-reported levels of pain and disability and duration of symptoms were not associated with size and shape of the oropharynx in whiplash subjects (P = 0.75 and P = 0.99, respectively). Age and BMI did influence the size (P = 0.01) and shape of the oropharynx (P < 0.001) in the whiplash subjects, but only 20 to 30 percent of the variance could be explained by these factors. Significant difference in the size and shape of the oropharynx was noted in subjects with chronic whiplash compared with controls. Future studies are required to investigate the relationships between oropharynx morphometry and symptoms in patients with chronic whiplash.

Phenotypic Plasticity of Leaf Shape along a Temperature Gradient in Acer rubrum

PubMed Central

Royer, Dana L.; Meyerson, Laura A.; Robertson, Kevin M.; Adams, Jonathan M.

2009-01-01

Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. PMID:19893620

Rare ecomorphological convergence on a complex adaptive landscape: Body size and diet mediate evolution of jaw shape in squirrels (Sciuridae).

PubMed

Zelditch, Miriam Leah; Ye, Ji; Mitchell, Jonathan S; Swiderski, Donald L

2017-03-01

Convergence is widely regarded as compelling evidence for adaptation, often being portrayed as evidence that phenotypic outcomes are predictable from ecology, overriding contingencies of history. However, repeated outcomes may be very rare unless adaptive landscapes are simple, structured by strong ecological and functional constraints. One such constraint may be a limitation on body size because performance often scales with size, allowing species to adapt to challenging functions by modifying only size. When size is constrained, species might adapt by changing shape; convergent shapes may therefore be common when size is limiting and functions are challenging. We examine the roles of size and diet as determinants of jaw shape in Sciuridae. As expected, size and diet have significant interdependent effects on jaw shape and ecomorphological convergence is rare, typically involving demanding diets and limiting sizes. More surprising is morphological without ecological convergence, which is equally common between and within dietary classes. Those cases, like rare ecomorphological convergence, may be consequences of evolving on an adaptive landscape shaped by many-to-many relationships between ecology and function, many-to-one relationships between form and performance, and one-to-many relationships between functionally versatile morphologies and ecology. On complex adaptive landscapes, ecological selection can yield different outcomes. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Identification of Major and Minor QTL for Ecologically Important Morphological Traits in Three-Spined Sticklebacks (Gasterosteus aculeatus)

PubMed Central

Liu, Jun; Shikano, Takahito; Leinonen, Tuomas; Cano, José Manuel; Li, Meng-Hua; Merilä, Juha

2014-01-01

Quantitative trait locus (QTL) mapping studies of Pacific three-spined sticklebacks (Gasterosteus aculeatus) have uncovered several genomic regions controlling variability in different morphological traits, but QTL studies of Atlantic sticklebacks are lacking. We mapped QTL for 40 morphological traits, including body size, body shape, and body armor, in a F2 full-sib cross between northern European marine and freshwater three-spined sticklebacks. A total of 52 significant QTL were identified at the 5% genome-wide level. One major QTL explaining 74.4% of the total variance in lateral plate number was detected on LG4, whereas several major QTL for centroid size (a proxy for body size), and the lengths of two dorsal spines, pelvic spine, and pelvic girdle were mapped on LG21 with the explained variance ranging from 27.9% to 57.6%. Major QTL for landmark coordinates defining body shape variation also were identified on LG21, with each explaining ≥15% of variance in body shape. Multiple QTL for different traits mapped on LG21 overlapped each other, implying pleiotropy and/or tight linkage. Thus, apart from providing confirmatory data to support conclusions born out of earlier QTL studies of Pacific sticklebacks, this study also describes several novel QTL of both major and smaller effect for ecologically important traits. The finding that many major QTL mapped on LG21 suggests that this linkage group might be a hotspot for genetic determinants of ecologically important morphological traits in three-spined sticklebacks. PMID:24531726

SU-D-201-04: Study On the Impact of Tumor Shape and Size On Drug Delivery to Pancreatic Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soltani, M; Bazmara, H; Sefidgar, M

Purpose: Drug delivery to solid tumors can be expressed physically using transport phenomena such as convection and diffusion for the drug of interest within extracellular matrices. We aimed to carefully model these phenomena, and to investigate the effect of tumor shape and size on drug delivery to solid tumors in the pancreas. Methods: In this study, multiple tumor geometries as obtained from clinical PET/CT images were considered. An advanced numerical method was used to simultaneously solve fluid flow and solute transport equations. Data from n=45 pancreatic cancer patients with non-resectable locoregional disease were analyzed, and geometrical information from the tumorsmore » including size, shape, and aspect ratios were classified. To investigate effect of tumor shape, tumors with similar size but different shapes were selected and analyzed. Moreover, to investigate effect of tumor size, tumors with similar shapes but different sizes, ranging from 1 to 77 cm{sup 3}, were selected and analyzed. A hypothetical tumor similar to one of the analyzed tumors, but scaled to reduce its size below 0.2 cm{sup 3}, was also analyzed. Results: The results showed relatively similar average drug concentration profiles in tumors with different sizes. Generally, smaller tumors had higher absolute drug concentration. In the hypothetical tumor, with volume less than 0.2 cm{sup 3}, the average drug concentration was 20% higher in comparison to its counterparts. For the various real tumor geometries, however, the maximum difference between average drug concentrations was 10% for the smallest and largest tumors. Moreover, the results demonstrated that for pancreatic tumors the shape is not significant. The negligible difference of drug concentration in different tumor shapes was due to the minimum effect of convection in pancreatic tumors. Conclusion: In tumors with different sizes, smaller tumors have higher drug delivery; however, the impact of tumor shape in the case of pancreatic tumors is not significant.« less

The effects of relative food item size on optimal tooth cusp sharpness during brittle food item processing

PubMed Central

Berthaume, Michael A.; Dumont, Elizabeth R.; Godfrey, Laurie R.; Grosse, Ian R.

2014-01-01

Teeth are often assumed to be optimal for their function, which allows researchers to derive dietary signatures from tooth shape. Most tooth shape analyses normalize for tooth size, potentially masking the relationship between relative food item size and tooth shape. Here, we model how relative food item size may affect optimal tooth cusp radius of curvature (RoC) during the fracture of brittle food items using a parametric finite-element (FE) model of a four-cusped molar. Morphospaces were created for four different food item sizes by altering cusp RoCs to determine whether optimal tooth shape changed as food item size changed. The morphospaces were also used to investigate whether variation in efficiency metrics (i.e. stresses, energy and optimality) changed as food item size changed. We found that optimal tooth shape changed as food item size changed, but that all optimal morphologies were similar, with one dull cusp that promoted high stresses in the food item and three cusps that acted to stabilize the food item. There were also positive relationships between food item size and the coefficients of variation for stresses in food item and optimality, and negative relationships between food item size and the coefficients of variation for stresses in the enamel and strain energy absorbed by the food item. These results suggest that relative food item size may play a role in selecting for optimal tooth shape, and the magnitude of these selective forces may change depending on food item size and which efficiency metric is being selected. PMID:25320068

Identification of Flood Reactivity Regions via the Functional Clustering of Hydrographs

NASA Astrophysics Data System (ADS)

Brunner, Manuela I.; Viviroli, Daniel; Furrer, Reinhard; Seibert, Jan; Favre, Anne-Catherine

2018-03-01

Flood hydrograph shapes contain valuable information on the flood-generation mechanisms of a catchment. To make good use of this information, we express flood hydrograph shapes as continuous functions using a functional data approach. We propose a clustering approach based on functional data for flood hydrograph shapes to identify a set of representative hydrograph shapes on a catchment scale and use these catchment-specific sets of representative hydrographs to establish regions of catchments with similar flood reactivity on a regional scale. We applied this approach to flood samples of 163 medium-size Swiss catchments. The results indicate that three representative hydrograph shapes sufficiently describe the hydrograph shape variability within a catchment and therefore can be used as a proxy for the flood behavior of a catchment. These catchment-specific sets of three hydrographs were used to group the catchments into three reactivity regions of similar flood behavior. These regions were not only characterized by similar hydrograph shapes and reactivity but also by event magnitudes and triggering event conditions. We envision these regions to be useful in regionalization studies, regional flood frequency analyses, and to allow for the construction of synthetic design hydrographs in ungauged catchments. The clustering approach based on functional data which establish these regions is very flexible and has the potential to be extended to other geographical regions or toward the use in climate impact studies.

Oval Window Size and Shape: a Micro-CT Anatomical Study With Considerations for Stapes Surgery.

PubMed

Zdilla, Matthew J; Skrzat, Janusz; Kozerska, Magdalena; Leszczyński, Bartosz; Tarasiuk, Jacek; Wroński, Sebastian

2018-06-01

The oval window is an important structure with regard to stapes surgeries, including stapedotomy for the treatment of otosclerosis. Recent study of perioperative imaging of the oval window has revealed that oval window niche height can indicate both operative difficulty and subjective discomfort during otosclerosis surgery. With regard to shape, structures incorporated into the oval window niche, such as cartilage grafts, must be compatible with the shape of the oval window. Despite the clinical importance of the oval window, there is little information regarding its size and shape. This study assessed oval window size and shape via micro-computed tomography paired with modern morphometric methodology in the fetal, infant, child, and adult populations. Additionally, the study compared oval window size and shape between sexes and between left- and right-sided ears. No significant differences were found among traditional morphometric parameters among age groups, sides, or sexes. However, geometric morphometric methods revealed shape differences between age groups. Further, geometric morphometric methods provided the average oval window shape and most-likely shape variance. Beyond demonstrating oval window size and shape variation, the results of this report will aid in identifying patients among whom anatomical variation may contribute to surgical difficulty and surgeon discomfort, or otherwise warrant preoperative adaptations for the incorporation of materials into and around the oval window.

A comparative test of adaptive hypotheses for sexual size dimorphism in lizards.

PubMed

Cox, Robert M; Skelly, Stephanie L; John-Alder, Henry B

2003-07-01

It is commonly argued that sexual size dimorphism (SSD) in lizards has evolved in response to two primary, nonexclusive processes: (1) sexual selection for large male size, which confers an advantage in intrasexual mate competition (intrasexual selection hypothesis), and (2) natural selection for large female size, which confers a fecundity advantage (fecundity advantage hypothesis). However, outside of several well-studied lizard genera, the empirical support for these hypotheses has not been examined with appropriate phylogenetic control. We conducted a comparative phylogenetic analysis to test these hypotheses using literature data from 497 lizard populations representing 302 species and 18 families. As predicted by the intrasexual selection hypothesis, male aggression and territoriality are correlated with SSD, but evolutionary shifts in these categorical variables each explain less than 2% of the inferred evolutionary change in SSD. We found stronger correlations between SSD and continuous estimates of intrasexual selection such as male to female home range ratio and female home range size. These results are consistent with the criticism that categorical variables may obscure much of the actual variation in intrasexual selection intensity needed to explain patterns in SSD. In accordance with the fecundity advantage hypothesis, SSD is correlated with clutch size, reproductive frequency, and reproductive mode (but not fecundity slope, reduced major axis estimator of fecundity slope, length of reproductive season, or latitude). However, evolutionary shifts in clutch size explain less than 8% of the associated change in SSD, which also varies significantly in the absence of evolutionary shifts in reproductive frequency and mode. A multiple regression model retained territoriality and clutch size as significant predictors of SSD, but only 16% of the variation in SSD is explained using these variables. Intrasexual selection for large male size and fecundity selection for large female size have undoubtedly helped to shape patterns of SSD across lizards, but the comparative data at present provide only weak support for these hypotheses as general explanations for SSD in this group. Future work would benefit from the consideration of alternatives to these traditional evolutionary hypotheses, and the elucidation of proximate mechanisms influencing growth and SSD within populations.

Geometric morphometrics reveals sex-differential shape allometry in a spider.

PubMed

Fernández-Montraveta, Carmen; Marugán-Lobón, Jesús

2017-01-01

Common scientific wisdom assumes that spider sexual dimorphism (SD) mostly results from sexual selection operating on males. However, testing predictions from this hypothesis, particularly male size hyperallometry, has been restricted by methodological constraints. Here, using geometric morphometrics (GMM) we studied for the first time sex-differential shape allometry in a spider ( Donacosa merlini , Araneae: Lycosidae) known to exhibit the reverse pattern (i.e., male-biased) of spider sexual size dimorphism. GMM reveals previously undetected sex-differential shape allometry and sex-related shape differences that are size independent (i.e., associated to the y-intercept, and not to size scaling). Sexual shape dimorphism affects both the relative carapace-to-opisthosoma size and the carapace geometry, arguably resulting from sex differences in both reproductive roles (female egg load and male competition) and life styles (wandering males and burrowing females). Our results demonstrate that body portions may vary modularly in response to different selection pressures, giving rise to sex differences in shape, which reconciles previously considered mutually exclusive interpretations about the origins of spider SD.

The impact of cigarette pack shape, size and opening: evidence from tobacco company documents.

PubMed

Kotnowski, Kathy; Hammond, David

2013-09-01

To use tobacco industry documents on cigarette pack shape, size and openings to identify industry findings on associations with brand imagery, product attributes, consumer perceptions and behaviour. Internal tobacco industry research and marketing documents obtained through court disclosure contained in the Legacy Tobacco Documents Library were searched using keywords related to pack shapes, sizes and opening methods. The search identified 66 documents related to consumer research and marketing plans on pack shape, size and openings, drawn from 1973 to 2002. Industry research consistently found that packs that deviated from the traditional flip-top box projected impressions of 'modern', 'elegant' and 'unique' brand imagery. Alternative pack shape and openings were identified as an effective means to communicate product attributes, particularly with regard to premium quality and smooth taste. Consumer studies consistently found that pack shape, size and opening style influenced perceptions of reduced product harm, and were often used to communicate a 'lighter' product. Slim, rounded, oval and booklet packs were found to be particularly appealing among young adults, and several studies demonstrated increased purchase interest for tobacco products presented in novel packaging shape or opening. Evidence from consumer tracking reports and company presentations indicate that pack innovations in shape or opening method increased market share of brands. Consumer research by the tobacco industry between 1973 and 2002 found that variations in packaging shape, size and opening method could influence brand appeal and risk perceptions and increase cigarette sales. © 2013 Society for the Study of Addiction.

Physicochemically Tunable Polyfunctionalized RNA Square Architecture with Fluorogenic and Ribozymatic Properties

PubMed Central

2015-01-01

Recent advances in RNA nanotechnology allow the rational design of various nanoarchitectures. Previous methods utilized conserved angles from natural RNA motifs to form geometries with specific sizes. However, the feasibility of producing RNA architecture with variable sizes using native motifs featuring fixed sizes and angles is limited. It would be advantageous to display RNA nanoparticles of diverse shape and size derived from a given primary sequence. Here, we report an approach to construct RNA nanoparticles with tunable size and stability. Multifunctional RNA squares with a 90° angle were constructed by tuning the 60° angle of the three-way junction (3WJ) motif from the packaging RNA (pRNA) of the bacteriophage phi29 DNA packaging motor. The physicochemical properties and size of the RNA square were also easily tuned by modulating the “core” strand and adjusting the length of the sides of the square via predictable design. Squares of 5, 10, and 20 nm were constructed, each showing diverse thermodynamic and chemical stabilities. Four “arms” extending from the corners of the square were used to incorporate siRNA, ribozyme, and fluorogenic RNA motifs. Unique intramolecular contact using the pre-existing intricacy of the 3WJ avoids relatively weaker intermolecular interactions via kissing loops or sticky ends. Utilizing the 3WJ motif, we have employed a modular design technique to construct variable-size RNA squares with controllable properties and functionalities for diverse and versatile applications with engineering, pharmaceutical, and medical potential. This technique for simple design to finely tune physicochemical properties adds a new angle to RNA nanotechnology. PMID:24971772

Self-associated submicron IgG1 particles for pulmonary delivery: effects of non-ionic surfactants on size, shape, stability, and aerosol performance.

PubMed

Srinivasan, Asha R; Shoyele, Sunday A

2013-03-01

The ability to produce submicron particles of monoclonal antibodies of different sizes and shapes would enhance their application to pulmonary delivery. Although non-ionic surfactants are widely used as stabilizers in protein formulations, we hypothesized that non-ionic surfactants will affect the shape and size of submicron IgG particles manufactured through precipitation. Submicron particles of IgG1 were produced by a precipitation process which explores the fact that proteins have minimum solubility but maximum precipitation at the isoelectric point. Non-ionic surfactants were used for size and shape control, and as stabilizing agents. Aerosol performance of the antibody nanoparticles was assessed using Andersen Cascade Impactor. Spinhaler® and Handihaler® were used as model DPI devices. SEM micrographs revealed that the shape of the submicron particles was altered by varying the type of surfactant added to the precipitating medium. Particle size as measured by dynamic light scattering was also varied based on the type and concentration of the surfactant. The surfactants were able to stabilize the IgG during the precipitation process. Polyhedral, sponge-like, and spherical nanoparticles demonstrated improved aerosolization properties compared to irregularly shaped (>20 μm) unprocessed particles. Stable antibody submicron particles of different shapes and sizes were prepared. Careful control of the shape of such particles is critical to ensuring optimized lung delivery by dry powder inhalation.

Investigation of Sclerotinia sclerotiorum strains variability in Brazil.

PubMed

Abreu, M J; Souza, E A

2015-06-18

White mold is a common bean disease caused by the fungus Sclerotinia sclerotiorum, resulting in economic losses in Brazil and worldwide. Lack of knowledge about the population structure of the pathogen makes it difficult to control the disease. The aim of this study was to characterize strains of S. sclerotiorum obtained from ex-perimental and commercial common bean fields in Brazil. We analyzed 50 strains of S. sclerotiorum collected at several locations in the state of Minas Gerais. The strains were characterized according to their ability and time for developing apothecia. Morphological and physiological analyses such as the mycelial growth index, colony color, the time re-quired to form the first sclerotia on media, the number of sclerotia per plate, average sclerotium size, and sclerotium shape were performed. We determined the mycelial compatibility, conducted molecular analy-sis of microsatellites, and evaluated the aggressiveness of 28 strains. Most strains had the ability to form apothecia. A small group of strains showed mycelial compatibility, and the strains showed different aggres-siveness levels. Overall, the population studied here demonstrated wide variability based on the morphological, physiological, and molecular traits analyzed. The average size and shape of sclerotia presented a cor-relation of 0.617, whereas the times required to form sclerotia and the number of sclerotia per plate showed a correlation of -0.455. The char-acterization of the pathogen population described herein will provide an important tool for promoting the development of bean cultivars re-sistant to white mold.

Human access and landscape structure effects on Andean forest bird richness

NASA Astrophysics Data System (ADS)

Aubad, Jorge; Aragón, Pedro; Rodríguez, Miguel Á.

2010-07-01

We analyzed the influence of human access and landscape structure on forest bird species richness in a fragmented landscape of the Colombian Andes. In Latin America, habitat loss and fragmentation are considered as the greatest threats to biodiversity because a large number of countryside villagers complement their food and incomes with the extraction of forest resources. Anthropogenic actions may also affect forest species by bird hunting or indirectly through modifying the structure of forest habitats. We surveyed 14 secondary cloud forest remnants to generate bird species richness data for each of them. We also quantified six landscape structure descriptors of forest patch size (patch area and core area), shape (perimeter of each fragment and the Patton's shape index) and isolation (nearest neighbor distance and edge contrast), and generated (using principal components analysis) a synthetic human influence variable based on the distance of each fragment to roads and villages, as well as the total slope of the fragments. Species richness was related to these variables using generalized linear models (GLMs) complemented with model selection techniques based on information theory and partial regression analysis. We found that forest patch size and accessibility were key drivers of bird richness, which increased toward largest patches, but decreased in those more accessible to humans and their potential disturbances. Both patch area and human access effects on forest bird species richness were complementary and similar in magnitude. Our results provide a basis for biodiversity conservation plans and initiatives of Andean forest diversity.

Effect of finite size in magnetic properties of BaFe12O19

NASA Astrophysics Data System (ADS)

Kumar, A. Sendil; Bhatnagar, Anil K.

2018-05-01

BaFe12O19 Nanoparticles are prepared through auto ignition method and structure, microstructure and magnetic properties are characterized. Samples having spherical shapes and elongated nanorods are chosen to investigate the role of finite size effect in magnetic properties. Magnetization studies show superparamagnetic, antiferromagnetic and ferrimagnetic behaviors depending on the size and shape. Very small coercive field of around 200 Oe is observed for spherical nanoparticles and a large coercive field of around 7000 Oe for nanorods is found. The shape and size plays an important role in magnetic properties of BaFe12O19 nanoparticles. Shape anisotropy has significant value compared to other anisotropies. Therefore shape of nanoparticles influences the magnetic order.

Crawling and turning in a minimal reaction-diffusion cell motility model: Coupling cell shape and biochemistry

NASA Astrophysics Data System (ADS)

Camley, Brian A.; Zhao, Yanxiang; Li, Bo; Levine, Herbert; Rappel, Wouter-Jan

2017-01-01

We study a minimal model of a crawling eukaryotic cell with a chemical polarity controlled by a reaction-diffusion mechanism describing Rho GTPase dynamics. The size, shape, and speed of the cell emerge from the combination of the chemical polarity, which controls the locations where actin polymerization occurs, and the physical properties of the cell, including its membrane tension. We find in our model both highly persistent trajectories, in which the cell crawls in a straight line, and turning trajectories, where the cell transitions from crawling in a line to crawling in a circle. We discuss the controlling variables for this turning instability and argue that turning arises from a coupling between the reaction-diffusion mechanism and the shape of the cell. This emphasizes the surprising features that can arise from simple links between cell mechanics and biochemistry. Our results suggest that similar instabilities may be present in a broad class of biochemical descriptions of cell polarity.

Nuclear Autonomy in Multinucleate Fungi

PubMed Central

Roberts, Samantha E.; Gladfelter, Amy S.

2015-01-01

Within many fungal syncytia, nuclei behave independently despite sharing a common cytoplasm. Creation of independent nuclear zones of control in one cell is paradoxical considering random protein synthesis sites, predicted rapid diffusion rates, and well-mixed cytosol. In studying the surprising fungal nuclear autonomy, new principles of cellular organization are emerging. We discuss the current understanding of nuclear autonomy, focusing on asynchronous cell cycle progression where most work has been directed. Mechanisms underlying nuclear autonomy are diverse including mRNA localization, ploidy variability, and nuclear spacing control. With the challenges fungal syncytia face due to cytoplasmic size and shape, they serve as powerful models for uncovering new subcellular organization modes, variability sources among isogenic uninucleate cells, and the evolution of multicellularity. PMID:26379197

Visual variability affects early verb learning.

PubMed

Twomey, Katherine E; Lush, Lauren; Pearce, Ruth; Horst, Jessica S

2014-09-01

Research demonstrates that within-category visual variability facilitates noun learning; however, the effect of visual variability on verb learning is unknown. We habituated 24-month-old children to a novel verb paired with an animated star-shaped actor. Across multiple trials, children saw either a single action from an action category (identical actions condition, for example, travelling while repeatedly changing into a circle shape) or multiple actions from that action category (variable actions condition, for example, travelling while changing into a circle shape, then a square shape, then a triangle shape). Four test trials followed habituation. One paired the habituated verb with a new action from the habituated category (e.g., 'dacking' + pentagon shape) and one with a completely novel action (e.g., 'dacking' + leg movement). The others paired a new verb with a new same-category action (e.g., 'keefing' + pentagon shape), or a completely novel category action (e.g., 'keefing' + leg movement). Although all children discriminated novel verb/action pairs, children in the identical actions condition discriminated trials that included the completely novel verb, while children in the variable actions condition discriminated the out-of-category action. These data suggest that - as in noun learning - visual variability affects verb learning and children's ability to form action categories. © 2014 The British Psychological Society.

Fabrication of a form- and size-variable microcellular-polymer-stabilized metal nanocomposite using supercritical foaming and impregnation for catalytic hydrogenation

PubMed Central

2012-01-01

This article presents the fabrication of size-controllable and shape-flexible microcellular high-density polyethylene-stabilized palladium nanoparticles (Pd/m-HDPE) using supercritical foaming, followed by supercritical impregnation. These nanomaterials are investigated for use as heterogeneous hydrogenation catalysts of biphenyls in supercritical carbon dioxide with no significant surface and inner mass transfer resistance. The morphology of the Pd/m-HDPE is examined using scanning electron microscopy images of the pores inside Pd/m-HDPE catalysts and transmission electron microscopy images of the Pd particles confined in an HDPE structure. This nanocomposite simplifies industrial design and operation. These Pd/m-HDPE catalysts can be recycled easily and reused without complex recovery and cleaning procedures. PMID:22651135

Comparing apples and pears: women's perceptions of their body size and shape.

PubMed

Thoma, Marie E; Hediger, Mary L; Sundaram, Rajeshwari; Stanford, Joseph B; Peterson, C Matthew; Croughan, Mary S; Chen, Zhen; Buck Louis, Germaine M

2012-10-01

Obesity is a growing public health problem among reproductive-aged women, with consequences for chronic disease risk and reproductive and obstetric morbidities. Evidence also suggests that body shape (i.e., regional fat distribution) may be independently associated with risk, yet it is not known if women adequately perceive their shape. This study aimed to assess the validity of self-reported body size and shape figure drawings when compared to anthropometric measures among reproductive-aged women. Self-reported body size was ascertained using the Stunkard nine-level figures and self-reported body shape using stylized pear, hourglass, rectangle, and apple figures. Anthropometry was performed by trained researchers. Body size and body mass index (BMI) were compared using Spearman's correlation coefficient. Fat distribution indicators were compared across body shapes for nonobese and obese women using analysis of variance (ANOVA) and Fisher's exact test. Percent agreement and kappa statistics were computed for apple and pear body shapes. The 131 women studied were primarily Caucasian (81%), aged 32 years, with a mean BMI of 27.1 kg/m(2) (range 16.6-52.8 kg/m(2)). The correlation between body size and BMI was 0.85 (p<0.001). Among nonobese women, waist-to-hip ratios (WHR) were 0.75, 0.75, 0.80, and 0.82 for pear, hourglass, rectangle, and apple, respectively (p<0.001). Comparing apples and pears, the percent agreement (kappa) for WHR≥0.80 was 83% (0.55). Self-reported size and shape were consistent with anthropometric measures commonly used to assess obesity and fat distribution, respectively. Self-reported body shape may be a useful proxy measure in addition to body size in large-scale surveys.

Pelvic Inlet Shape Is Not as Dimorphic as Previously Suggested.

PubMed

Delprete, Hillary

2017-04-01

It is well known that there are significant differences in the pelves of males and females due, in part, to differing constraints. The male and female pelves must be suitable for upright posture and locomotion, but the female pelvis must also be suitable for reproduction. These differing requirements lead to differences in the shape and size of various pelvic dimensions. These differences are reflected in the pelvic inlet, midplane, and outlet. Current research has documented dimorphisms in the posterior and anterior spaces in all three of these planes. One measure however, that is calculated from the relationship between the length of the anterior-posterior diameter (APD) and the transverse diameter (TD) of the inlet, is not as dimorphic as previously suggested. This computed value is used to describe four main categories of inlet shape: android, gynecoid, anthropoid, and platypelloid. Current textbooks in anatomy and midwifery describe these forms and identify the typical male inlet shape as android and the typical female inlet shape as gynecoid. In this study, however, using skeletonized pelves of 378 adult individuals from three identified skeletal collections, the most common inlet shape for both males and females was android. In addition, when examining shape as a continuous variable, inlet shape is not sexually dimorphic in two of the three populations examined in this study. Based on the results of this study, the inlet shape for males and females is less dimorphic than previously thought, and we need to discontinue using pelvic categories to describe typical inlet shape. Anat Rec, 300:706-715, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Shape and Size of Microfine Aggregates: X-ray Microcomputed Tomgraphy vs. Laser Diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erdogan,S.; Garboczi, E.; Fowler, D.

Microfine rock aggregates, formed naturally or in a crushing process, pass a No. 200 ASTM sieve, so have at least two orthogonal principal dimensions less than 75 {mu}m, the sieve opening size. In this paper, for the first time, we capture true 3-D shape and size data of several different types of microfine aggregates, using X-ray microcomputed tomography ({mu}CT) with a voxel size of 2 {mu}m. This information is used to generate shape analyses of various kinds. Particle size distributions are also generated from the {mu}CT data and quantitatively compared to the results of laser diffraction, which is the leadingmore » method for measuring particle size distributions of sub-millimeter size particles. By taking into account the actual particle shape, the differences between {mu}CT and laser diffraction can be qualitatively explained.« less

Contribution of the hydrostatic pressure to the shape of silver island particles

NASA Astrophysics Data System (ADS)

Anno, E.; Hoshino, R.

1984-09-01

We have investigated the shape change of silver island particles caused by the surface energy reduction. When the surface energy was reduced by the reaction with hydrogen sulfide, the flattening of the particles was observed. As is well known, the similar shape change takes place when the particle size increases. Therefore, the particle shape is considered to depend both on the surface energy and the particle size. From this consideration, we predict the contribution of the hydrostatic pressure P to the particle shape. As evidence of this contribution, we consider the existence of the critical size below which P is larger than the adhesive force FA between deposit and substrate surface. Investigating the influence of the flattening due to the surface energy reduction on the size distribution, the critical size is found and estimated to be about 80 Å in diameter. This value is comparable with that estimated from the condition P = FA.

Monodisperse Block Copolymer Particles with Controllable Size, Shape, and Nanostructure

NASA Astrophysics Data System (ADS)

Shin, Jae Man; Kim, Yongjoo; Kim, Bumjoon; PNEL Team

Shape-anisotropic particles are important class of novel colloidal building block for their functionality is more strongly governed by their shape, size and nanostructure compared to conventional spherical particles. Recently, facile strategy for producing non-spherical polymeric particles by interfacial engineering received significant attention. However, achieving uniform size distribution of particles together with controlled shape and nanostructure has not been achieved. Here, we introduce versatile system for producing monodisperse BCP particles with controlled size, shape and morphology. Polystyrene-b-polybutadiene (PS-b-PB) self-assembled to either onion-like or striped ellipsoid particle, where final structure is governed by amount of adsorbed sodium dodecyl sulfate (SDS) surfactant at the particle/surrounding interface. Further control of molecular weight and particle size enabled fine-tuning of aspect ratio of ellipsoid particle. Underlying physics of free energy for morphology formation and entropic penalty associated with bending BCP chains strongly affects particle structure and specification.

Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution

PubMed Central

Soo, Oi Yoon Michelle; Tan, Wooi Boon; Lim, Lee Hong Susan

2016-01-01

Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams’s Kmult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data. Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root point, and the length between the inner root point and the dent point. The species on M. buchanani evolved larger, more robust anchors; those on L. subviridis evolved smaller, more delicate anchors. Anchor shape and size were significantly correlated, suggesting constraints in anchor evolution. Tight integration between the root and the point compartments within anchors confirms the anchor as a single, fully integrated module. The correlation between male copulatory organ morphology and size with anchor shape was consistent with predictions from the Rohde-Hobbs hypothesis. Conclusions. Monogenean anchors are tightly integrated structures, and their shape variation correlates strongly with phylogeny, thus underscoring their value for systematic and evolutionary biology studies. Our MonogeneaGM R package provides tools for researchers to mine biological insights from geometric morphometric data of speciose monogenean genera. PMID:26966649

Effect of shape and size of lung and chest wall on stresses in the lung

NASA Technical Reports Server (NTRS)

Vawter, D. L.; Matthews, F. L.; West, J. B.

1975-01-01

To understand better the effect of shape and size of lung and chest wall on the distribution of stresses, strains, and surface pressures, we analyzed a theoretical model using the technique of finite elements. First we investigated the effects of changing the chest wall shape during expansion, and second we studied lungs of a variety of inherent shapes and sizes. We found that, in general, the distributions of alveolar size, mechanical stresses, and surface pressures in the lungs were dominated by the weight of the lung and that changing the shape of the lung or chest wall had relatively little effect. Only at high states of expansion where the lung was very stiff did changing the shape of the chest wall cause substantial changes. Altering the inherent shape of the lung generally had little effect but the topographical differences in stresses and surface pressures were approximately proportional to lung height. The results are generally consistent with those found in the dog by Hoppin et al (1969).

A theoretical approach to study the melting temperature of metallic nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arora, Neha; Joshi, Deepika P.

2016-05-23

The physical properties of any material change with the change of its size from bulk range to nano range. A theoretical study to account for the size and shape effect on melting temperature of metallic nanowires has been done. We have studied zinc (Zn), indium (In), lead (Pb) and tin (Sn) nanowires with three different cross sectional shapes like regular triangular, square and regular hexagonal. Variation of melting temperature with the size and shape is graphically represented with the available experimental data. It was found that melting temperature of the nanowires decreases with decrement in the size of nanowire, duemore » to surface effect and at very small size the most probable shape also varies with material.« less

The Geomorphically Effective Hydrograph: An Emerging Concept For Interpreting Channel Morphology And Evolution

NASA Astrophysics Data System (ADS)

Grant, G.; Hempel, L. A.; Marwan, H.; Eaton, B. C.; Lewis, S.

2017-12-01

Predicting how alluvial channels adjust to changes in their flow and sediment regimes is one of the Holy Grails of geomorphology. Consider Lane's balance - one of the most widely recognized conceptual models in geomorphology - which graphically shows how a change in any one of the driving variables of slope, grain size, sediment transport rate, or discharge can be accommodated by changes in the other variables. Much of the history of process geomorphology addresses how channels respond to these controlling factors. Yet the emphasis has been disproportionately focused on the effects and consequences of changing sediment transport rates or grain size. Much less attention has been paid to how changing discharge itself, particularly over short, event-based timescales influences the channel. Discharge has typically been treated as a single value - often the bankfull discharge - with little attention paid to how the unsteady nature of flow during floods may influence the morphology of the channel. More attention has been paid recently to the effect of hydrograph shape on channel characteristics, notably the texture of the channel bed. There is little theory and scant data, however, that highlights how the hydrograph affects the channel. We have begun to address this problem through models and targeted experiments. Our goal is to explore the idea of the geomorphically effective hydrograph: the concept that hydrographs with different forms, durations, and sequences play a major, controlling role in shaping the form and organization of alluvial channels. We report on results from both field studies and flume experiments that lend support to this hypothesis. We compare channel forms in channels with radically different flow regimes. The distinctive rectangular shape, constant slope, and absence of alluvial bars in spring-fed channels are in sharp contrast to the more asymmetric channels with regular pool/riffle patterns observed in systems where discharge varies over orders of magnitude. Flume studies reveal how channel organization, defined as the tendency to form regularly-spaced pools, riffles, and bars, is related to the flashiness of the hydrograph. Drawing on these and other studies, we develop a conceptual model that accounts for hydrograph shape as an overarching control on channel development and evolution.

How river rocks round: resolving the shape-size paradox.

PubMed

Domokos, Gabor; Jerolmack, Douglas J; Sipos, Andras Á; Török, Akos

2014-01-01

River-bed sediments display two universal downstream trends: fining, in which particle size decreases; and rounding, where pebble shapes evolve toward ellipsoids. Rounding is known to result from transport-induced abrasion; however many researchers argue that the contribution of abrasion to downstream fining is negligible. This presents a paradox: downstream shape change indicates substantial abrasion, while size change apparently rules it out. Here we use laboratory experiments and numerical modeling to show quantitatively that pebble abrasion is a curvature-driven flow problem. As a consequence, abrasion occurs in two well-separated phases: first, pebble edges rapidly round without any change in axis dimensions until the shape becomes entirely convex; and second, axis dimensions are then slowly reduced while the particle remains convex. Explicit study of pebble shape evolution helps resolve the shape-size paradox by reconciling discrepancies between laboratory and field studies, and enhances our ability to decipher the transport history of a river rock.

How River Rocks Round: Resolving the Shape-Size Paradox

PubMed Central

Domokos, Gabor; Jerolmack, Douglas J.; Sipos, Andras Á.; Török, Ákos

2014-01-01

River-bed sediments display two universal downstream trends: fining, in which particle size decreases; and rounding, where pebble shapes evolve toward ellipsoids. Rounding is known to result from transport-induced abrasion; however many researchers argue that the contribution of abrasion to downstream fining is negligible. This presents a paradox: downstream shape change indicates substantial abrasion, while size change apparently rules it out. Here we use laboratory experiments and numerical modeling to show quantitatively that pebble abrasion is a curvature-driven flow problem. As a consequence, abrasion occurs in two well-separated phases: first, pebble edges rapidly round without any change in axis dimensions until the shape becomes entirely convex; and second, axis dimensions are then slowly reduced while the particle remains convex. Explicit study of pebble shape evolution helps resolve the shape-size paradox by reconciling discrepancies between laboratory and field studies, and enhances our ability to decipher the transport history of a river rock. PMID:24533132

Simultaneous Comparison of Two Roller Compaction Techniques and Two Particle Size Analysis Methods.

PubMed

Saarinen, Tuomas; Antikainen, Osmo; Yliruusi, Jouko

2017-11-01

A new dry granulation technique, gas-assisted roller compaction (GARC), was compared with conventional roller compaction (CRC) by manufacturing 34 granulation batches. The process variables studied were roll pressure, roll speed, and sieve size of the conical mill. The main quality attributes measured were granule size and flow characteristics. Within granulations also the real applicability of two particle size analysis techniques, sieve analysis (SA) and fast imaging technique (Flashsizer, FS), was tested. All granules obtained were acceptable. In general, the particle size of GARC granules was slightly larger than that of CRC granules. In addition, the GARC granules had better flowability. For example, the tablet weight variation of GARC granules was close to 2%, indicating good flowing and packing characteristics. The comparison of the two particle size analysis techniques showed that SA was more accurate in determining wide and bimodal size distributions while FS showed narrower and mono-modal distributions. However, both techniques gave good estimates for mean granule sizes. Overall, SA was a time-consuming but accurate technique that provided reliable information for the entire granule size distribution. By contrast, FS oversimplified the shape of the size distribution, but nevertheless yielded acceptable estimates for mean particle size. In general, FS was two to three orders of magnitude faster than SA.

Low-Dimensional Statistics of Anatomical Variability via Compact Representation of Image Deformations.

PubMed

Zhang, Miaomiao; Wells, William M; Golland, Polina

2016-10-01

Using image-based descriptors to investigate clinical hypotheses and therapeutic implications is challenging due to the notorious "curse of dimensionality" coupled with a small sample size. In this paper, we present a low-dimensional analysis of anatomical shape variability in the space of diffeomorphisms and demonstrate its benefits for clinical studies. To combat the high dimensionality of the deformation descriptors, we develop a probabilistic model of principal geodesic analysis in a bandlimited low-dimensional space that still captures the underlying variability of image data. We demonstrate the performance of our model on a set of 3D brain MRI scans from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Our model yields a more compact representation of group variation at substantially lower computational cost than models based on the high-dimensional state-of-the-art approaches such as tangent space PCA (TPCA) and probabilistic principal geodesic analysis (PPGA).

The unusual suspect: Land use is a key predictor of biodiversity patterns in the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Martins, Inês Santos; Proença, Vânia; Pereira, Henrique Miguel

2014-11-01

Although land use change is a key driver of biodiversity change, related variables such as habitat area and habitat heterogeneity are seldom considered in modeling approaches at larger extents. To address this knowledge gap we tested the contribution of land use related variables to models describing richness patterns of amphibians, reptiles and passerines in the Iberian Peninsula. We analyzed the relationship between species richness and habitat heterogeneity at two spatial resolutions (i.e., 10 km × 10 km and 50 km × 50 km). Using both ordinary least square and simultaneous autoregressive models, we assessed the relative importance of land use variables, climate variables and topographic variables. We also compare the species-area relationship with a multi-habitat model, the countryside species-area relationship, to assess the role of the area of different types of habitats on species diversity across scales. The association between habitat heterogeneity and species richness varied with the taxa and spatial resolution. A positive relationship was detected for all taxa at a grain size of 10 km × 10 km, but only passerines responded at a grain size of 50 km × 50 km. Species richness patterns were well described by abiotic predictors, but habitat predictors also explained a considerable portion of the variation. Moreover, species richness patterns were better described by a multi-habitat species-area model, incorporating land use variables, than by the classic power model, which only includes area as the single explanatory variable. Our results suggest that the role of land use in shaping species richness patterns goes beyond the local scale and persists at larger spatial scales. These findings call for the need of integrating land use variables in models designed to assess species richness response to large scale environmental changes.

Wing shape allometry and aerodynamics in calopterygid damselflies: a comparative approach.

PubMed

Outomuro, David; Adams, Dean C; Johansson, Frank

2013-06-07

Wing size and shape have important aerodynamic implications on flight performance. We explored how wing size was related to wing shape in territorial males of 37 taxa of the damselfly family Calopterygidae. Wing coloration was also included in the analyses because it is sexually and naturally selected and has been shown to be related to wing shape. We studied wing shape using both the non-dimensional radius of the second moment of wing area (RSM) and geometric morphometrics. Lower values of the RSM result in less energetically demanding flight and wider ranges of flight speed. We also re-analyzed previously published data on other damselflies and dragonflies. The RSM showed a hump-shaped relationship with wing size. However, after correcting for phylogeny using independent contrast, this pattern changed to a negative linear relationship. The basal genus of the study family, Hetaerina, was mainly driving that change. The obtained patterns were specific for the study family and differed from other damselflies and dragonflies. The relationship between the RSM and wing shape measured by geometric morphometrics was linear, but relatively small changes along the RSM axis can result in large changes in wing shape. Our results also showed that wing coloration may have some effect on RSM. We found that RSM showed a complex relationship with size in calopterygid damselflies, probably as a result of other selection pressures besides wing size per se. Wing coloration and specific behavior (e.g. courtship) are potential candidates for explaining the complexity. Univariate measures of wing shape such as RSM are more intuitive but lack the high resolution of other multivariate techniques such as geometric morphometrics. We suggest that the relationship between wing shape and size are taxa-specific and differ among closely-related insect groups.

The John Insall Award: Both morphotype and gender influence the shape of the knee in patients undergoing TKA.

PubMed

Bellemans, Johan; Carpentier, Karel; Vandenneucker, Hilde; Vanlauwe, Johan; Victor, Jan

2010-01-01

There is an ongoing debate whether gender differences in the dimensions of the knee should influence the design of TKA components. We hypothesized that not only gender but also the patient's morphotype determined the shape of the distal femur and proximal tibia and that this factor should be taken into account when designing gender-specific TKA implants. We reviewed all 1000 European white patients undergoing TKA between April 2003 and June 2007 and stratified each into one of three groups based on their anatomic constitution: endomorph, ectomorph, or mesomorph. Of the 250 smallest knees, 98% were female, whereas 81% of the 250 largest knees were male. In the group with intermediate-sized knees, female knees were narrower than male knees. Patients with smaller knees (predominantly female) demonstrated large variability between narrow and wide mediolateral dimensions irrespective of gender. The same was true for larger knees (predominantly male). This variability within gender could partially be explained by morphotypic variation. Patients with short and wide morphotype (endomorph) had, irrespective of gender, wider knees, whereas patients with long and narrow morphotype (ectomorph) had narrower knees. The shape of the knee is therefore not only dependent on gender, but also on the morphotype of the patient. Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Generating Multivariate Ordinal Data via Entropy Principles.

PubMed

Lee, Yen; Kaplan, David

2018-03-01

When conducting robustness research where the focus of attention is on the impact of non-normality, the marginal skewness and kurtosis are often used to set the degree of non-normality. Monte Carlo methods are commonly applied to conduct this type of research by simulating data from distributions with skewness and kurtosis constrained to pre-specified values. Although several procedures have been proposed to simulate data from distributions with these constraints, no corresponding procedures have been applied for discrete distributions. In this paper, we present two procedures based on the principles of maximum entropy and minimum cross-entropy to estimate the multivariate observed ordinal distributions with constraints on skewness and kurtosis. For these procedures, the correlation matrix of the observed variables is not specified but depends on the relationships between the latent response variables. With the estimated distributions, researchers can study robustness not only focusing on the levels of non-normality but also on the variations in the distribution shapes. A simulation study demonstrates that these procedures yield excellent agreement between specified parameters and those of estimated distributions. A robustness study concerning the effect of distribution shape in the context of confirmatory factor analysis shows that shape can affect the robust [Formula: see text] and robust fit indices, especially when the sample size is small, the data are severely non-normal, and the fitted model is complex.

Nutrition warnings as front-of-pack labels: influence of design features on healthfulness perception and attentional capture.

PubMed

Cabrera, Manuel; Machín, Leandro; Arrúa, Alejandra; Antúnez, Lucía; Curutchet, María Rosa; Giménez, Ana; Ares, Gastón

2017-12-01

Warnings are a new directive front-of-pack (FOP) nutrition labelling scheme that highlights products with high content of key nutrients. The design of warnings influences their ability to catch consumers' attention and to clearly communicate their intended meaning, which are key determinants of their effectiveness. The aim of the present work was to evaluate the influence of design features of warnings as a FOP nutrition labelling scheme on perceived healthfulness and attentional capture. Five studies with a total of 496 people were carried out. In the first study, the association of colour and perceived healthfulness was evaluated in an online survey in which participants had to rate their perceived healthfulness of eight colours. In the second study, the influence of colour, shape and textual information on perceived healthfulness was evaluated using choice-conjoint analysis. The third study focused on implicit associations between two design features (shape and colour) on perceived healthfulness. The fourth and fifth studies used visual search to evaluate the influence of colour, size and position of the warnings on attentional capture. Perceived healthfulness was significantly influenced by shape, colour and textual information. Colour was the variable with the largest contribution to perceived healthfulness. Colour, size and position of the warnings on the labels affected attentional capture. Results from the experiments provide recommendations for the design of warnings to identify products with unfavourable nutrient profile.

Event-related potentials during word mapping to object shape predict toddlers' vocabulary size

PubMed Central

Borgström, Kristina; Torkildsen, Janne von Koss; Lindgren, Magnus

2015-01-01

What role does attention to different object properties play in early vocabulary development? This longitudinal study using event-related potentials in combination with behavioral measures investigated 20- and 24-month-olds' (n = 38; n = 34; overlapping n = 24) ability to use object shape and object part information in word-object mapping. The N400 component was used to measure semantic priming by images containing shape or detail information. At 20 months, the N400 to words primed by object shape varied in topography and amplitude depending on vocabulary size, and these differences predicted productive vocabulary size at 24 months. At 24 months, when most of the children had vocabularies of several hundred words, the relation between vocabulary size and the N400 effect in a shape context was weaker. Detached object parts did not function as word primes regardless of age or vocabulary size, although the part-objects were identified behaviorally. The behavioral measure, however, also showed relatively poor recognition of the part-objects compared to the shape-objects. These three findings provide new support for the link between shape recognition and early vocabulary development. PMID:25762957

Dimensional analysis of the endometrial cavity: how many dimensions should the ideal intrauterine device or system have?

PubMed

Goldstuck, Norman D

2018-01-01

The geometrical shape of the human uterus most closely approximates that of a prolate ellipsoid. The endometrial cavity itself is more likely to also have the shape of a prolate ellipsoid especially when the extension of the cervix is omitted. Using this information and known endometrial cavity volumes and lateral and vertical dimensions, it is possible to calculate the anteroposterior (AP) dimensions and get a complete evaluation of all possible dimensions of the endometrial cavity. These are singular observations and not part of any other study. The AP dimensions of the endometrial cavity of the uterus were calculated using the formula for the volume of the prolate ellipsoid to complete a three-dimensional picture of the endometrial cavity. Calculations confirm ultrasound imaging which shows large variations in cavity size and shape. Known cavity volumes and length and breadth measurements indicate that the AP diameter may vary from 6.29 to 38.2 mm. These measurements confirm the difficulty of getting a fixed-frame intrauterine device (IUD) to accommodate to a space of highly variable dimensions. This is especially true of three-dimension IUDs. A one-dimensional frameless IUD is most likely to be able to conform to this highly variable space and shape. The endometrial cavity may assume many varied prolate ellipsoid configurations where one or more measurements may be too small to accommodate standard IUDs. A one-dimensional device is most likely to be able to be accommodated by most uterine cavities as compared to two- and three-dimensional devices.

Bite of the cats: relationships between functional integration and mechanical performance as revealed by mandible geometry.

PubMed

Piras, Paolo; Maiorino, Leonardo; Teresi, Luciano; Meloro, Carlo; Lucci, Federico; Kotsakis, Tassos; Raia, Pasquale

2013-11-01

Cat-like carnivorous mammals represent a relatively homogeneous group of species whose morphology appears constrained by exclusive adaptations for meat eating. We present the most comprehensive data set of extant and extinct cat-like species to test for evolutionary transformations in size, shape and mechanical performance, that is, von Mises stress and surface traction, of the mandible. Size and shape were both quantified by means of geometric morphometrics, whereas mechanical performance was assessed applying finite element models to 2D geometry of the mandible. Additionally, we present the first almost complete composite phylogeny of cat-like carnivorans for which well-preserved mandibles are known, including representatives of 35 extant and 59 extinct species of Felidae, Nimravidae, and Barbourofelidae. This phylogeny was used to test morphological differentiation, allometry, and covariation of mandible parts within and among clades. After taking phylogeny into account, we found that both allometry and mechanical variables exhibit a significant impact on mandible shape. We also tested whether mechanical performance was linked to morphological integration. Mechanical stress at the coronoid process is higher in sabertoothed cats than in any other clade. This is strongly related to the high degree of covariation within modules of sabertooths mandibles. We found significant correlation between integration at the clade level and per-clade averaged stress values, on both original data and by partialling out interclade allometry from shapes when calculating integration. This suggests a strong interaction between natural selection and the evolution of developmental and functional modules at the clade level.

Measurement of Size-dependent Dynamic Shape Factors of Quartz Particles in Two Flow Regimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexander, Jennifer M.; Bell, David M.; Imre, D.

2016-08-02

Understanding and modeling the behavior of quartz dust particles, commonly found in the atmosphere, requires knowledge of many relevant particles properties, including particle shape. This study uses a single particle mass spectrometer, a differential mobility analyzer, and an aerosol particle mass analyzer to measure quartz aerosol particles mobility, aerodynamic, and volume equivalent diameters, mass, composition, effective density, and dynamic shape factor as a function of particle size, in both the free molecular and transition flow regimes. The results clearly demonstrate that dynamic shape factors can vary significantly as a function of particle size. For the quartz samples studied here, themore » dynamic shape factors increase with size, indicating that larger particles are significantly more aspherical than smaller particles. In addition, dynamic shape factors measured in the free-molecular (χv) and transition (χt) flow regimes can be significantly different, and these differences vary with the size of the quartz particles. For quartz, χv of small (d < 200 nm) particles is 1.25, while χv of larger particles (d ~ 440 nm) is 1.6, with a continuously increasing trend with particle size. In contrast χt, of small particles starts at 1.1 increasing slowly to 1.34 for 550 nm diameter particles. The multidimensional particle characterization approach used here goes beyond determination of average properties for each size, to provide additional information about how the particle dynamic shape factor may vary even for particles with the same mass and volume equivalent diameter.« less

Reverberation Mapping the Dusty Torus in Active Galactic Nuclei: the Influence of Torus Geometry and Structure on the Measured Reverberation Radius

NASA Astrophysics Data System (ADS)

Almeyda, Triana

2018-01-01

The obscuring circumnuclear dusty torus is a cornerstone of AGN unification, yet its shape, composition, and structure have not been well constrained. Infrared (IR) interferometry can partially resolve the dust structures in nearby AGN. However, the size and structure of the torus can also be investigated at all redshifts by reverberation mapping, that is, analyzing the temporal variability of the torus dust emission in response to changes in the AGN luminosity. In simple models, the lag between the AGN optical continuum variations and the torus IR response is directly related to the effective size of the emitting region. However, the IR response is sensitive to many poorly constrained variables including the geometry and illumination of the torus, which complicates the interpretation of measured reverberation lags. I will present results from the first comprehensive analysis of the multi-wavelength IR torus response, showing how various structural and geometrical torus parameters influence the measured lag. A library of torus response functions has been computed using a new code, TORMAC, which simulates the temporal response of the IR emission of a 3D ensemble of dust clouds given an input optical light curve. TORMAC accounts for anisotropic emission from the dust clouds, inter-cloud and AGN-cloud shadowing, and anisotropic illumination of the torus by the AGN continuum source. We can use the model grid to quantify the relationship between the lag and the effective size of the torus for various torus parameters at any selected wavelength. Although the shapes of the response functions vary widely over our grid parameter range, the reverberation lag provides an estimate of the effective torus radius that is always within a factor of 2.5. TORMAC can also be used to model observed IR light curves; we present preliminary simulations for the “changing-look” Seyfert galaxy, NGC 6418, which exhibited large IR variability during a recent Spitzer monitoring campaign. This work will aid in the interpretation of reverberation mapping measurements, especially for the new VEILS wide field near-IR extragalactic time domain survey, whose aim is to use AGN IR reverberation mapping lags as cosmological standard candles.

Confounding environmental colour and distribution shape leads to underestimation of population extinction risk.

PubMed

Fowler, Mike S; Ruokolainen, Lasse

2013-01-01

The colour of environmental variability influences the size of population fluctuations when filtered through density dependent dynamics, driving extinction risk through dynamical resonance. Slow fluctuations (low frequencies) dominate in red environments, rapid fluctuations (high frequencies) in blue environments and white environments are purely random (no frequencies dominate). Two methods are commonly employed to generate the coloured spatial and/or temporal stochastic (environmental) series used in combination with population (dynamical feedback) models: autoregressive [AR(1)] and sinusoidal (1/f) models. We show that changing environmental colour from white to red with 1/f models, and from white to red or blue with AR(1) models, generates coloured environmental series that are not normally distributed at finite time-scales, potentially confounding comparison with normally distributed white noise models. Increasing variability of sample Skewness and Kurtosis and decreasing mean Kurtosis of these series alter the frequency distribution shape of the realised values of the coloured stochastic processes. These changes in distribution shape alter patterns in the probability of single and series of extreme conditions. We show that the reduced extinction risk for undercompensating (slow growing) populations in red environments previously predicted with traditional 1/f methods is an artefact of changes in the distribution shapes of the environmental series. This is demonstrated by comparison with coloured series controlled to be normally distributed using spectral mimicry. Changes in the distribution shape that arise using traditional methods lead to underestimation of extinction risk in normally distributed, red 1/f environments. AR(1) methods also underestimate extinction risks in traditionally generated red environments. This work synthesises previous results and provides further insight into the processes driving extinction risk in model populations. We must let the characteristics of known natural environmental covariates (e.g., colour and distribution shape) guide us in our choice of how to best model the impact of coloured environmental variation on population dynamics.

Robust functional statistics applied to Probability Density Function shape screening of sEMG data.

PubMed

Boudaoud, S; Rix, H; Al Harrach, M; Marin, F

2014-01-01

Recent studies pointed out possible shape modifications of the Probability Density Function (PDF) of surface electromyographical (sEMG) data according to several contexts like fatigue and muscle force increase. Following this idea, criteria have been proposed to monitor these shape modifications mainly using High Order Statistics (HOS) parameters like skewness and kurtosis. In experimental conditions, these parameters are confronted with small sample size in the estimation process. This small sample size induces errors in the estimated HOS parameters restraining real-time and precise sEMG PDF shape monitoring. Recently, a functional formalism, the Core Shape Model (CSM), has been used to analyse shape modifications of PDF curves. In this work, taking inspiration from CSM method, robust functional statistics are proposed to emulate both skewness and kurtosis behaviors. These functional statistics combine both kernel density estimation and PDF shape distances to evaluate shape modifications even in presence of small sample size. Then, the proposed statistics are tested, using Monte Carlo simulations, on both normal and Log-normal PDFs that mimic observed sEMG PDF shape behavior during muscle contraction. According to the obtained results, the functional statistics seem to be more robust than HOS parameters to small sample size effect and more accurate in sEMG PDF shape screening applications.

Imaging of thymic disorders

PubMed Central

Bogot, Naama R; Quint, Leslie E

2005-01-01

Evaluation of the thymus poses a challenge to the radiologist. In addition to age-related changes in thymic size, shape, and tissue composition, there is considerable variability in the normal adult thymic appearance within any age group. Many different types of disorders may affect the thymus, including hyperplasia, cysts, and benign and malignant neoplasms, both primary and secondary; clinical and imaging findings typical for each disease process are described in this article. Whereas computed tomography is the mainstay for imaging the thymus, other imaging modalities may occasionally provide additional structural or functional information. PMID:16361143

A study of some fundamental physicochemical variables on the morphology of mesoporous silica nanoparticles MCM-41 type

NASA Astrophysics Data System (ADS)

Beltrán-Osuna, Ángela A.; Gómez Ribelles, José L.; Perilla, Jairo E.

2017-12-01

All variables affecting the morphology of mesoporous silica nanoparticles (MSN) should be carefully analyzed in order to truly tailored design their mesoporous structure according to their final use. Although complete control on MCM-41 synthesis has been already claimed, reproducibility and repeatability of results remain a big issue due to the lack of information reported in literature. Stirring rate, reaction volume, and system configuration (i.e., opened or closed reactor) are three variables that are usually omitted, making the comparison of product characteristics difficult. Specifically, the rate of solvent evaporation is seldom disclosed, and its influence has not been previously analyzed. These variables were systematically studied in this work, and they were proven to have a fundamental impact on final particle morphology. Hence, a high degree of circularity ( C = 0.97) and monodispersed particle size distributions were only achieved when a stirring speed of 500 rpm and a reaction scale of 500 mL were used in a partially opened system, for a 2 h reaction at 80 °C. Well-shaped spherical mesoporous silica nanoparticles with a diameter of 95 nm, a pore size of 2.8 nm, and a total surface area of 954 m2 g-1 were obtained. Final characteristics made this product suitable to be used in biomedicine and nanopharmaceutics, especially for the design of drug delivery systems.

Comparison of marginal adaptation of mineral trioxide aggregate, glass ionomer cement and intermediate restorative material as root-end filling materials, using scanning electron microscope: An in vitro study

PubMed Central

Gundam, Sirisha; Patil, Jayaprakash; Venigalla, Bhuvan Shome; Yadanaparti, Sravanthi; Maddu, Radhika; Gurram, Sindhura Reddy

2014-01-01

Aim: The present study compares the marginal adaption of Mineral Trioxide Aggregate (MTA), Glass Ionomer Cement (GIC) and Intermediate Restorative Material (IRM) as root-end filling materials in extracted human teeth using Scanning Electron Microscope (SEM). Materials and Methods: Thirty single rooted human teeth were obturated with Gutta-percha after cleaning and shaping. Apical 3 mm of roots were resected and retrofilled with MTA, GIC and IRM. One millimeter transverse section of the retrofilled area was used to study the marginal adaptation of the restorative material with the dentin. Mounted specimens were examined using SEM at approximately 15 Kv and 10-6 Torr under high vacuum condition. At 2000 X magnification, the gap size at the material-tooth interface was recorded at 2 points in microns. Statistical Analysis: One way ANOVA Analysis of the data from the experimental group was carried out with gap size as the dependent variable, and material as independent variable. Results: The lowest mean value of gap size was recorded in MTA group (0.722 ± 0.438 μm) and the largest mean gap in GIC group (1.778 ± 0.697 μm). Conclusion: MTA showed least gap size when compared to IRM and GIC suggesting a better marginal adaptation. PMID:25506146

Consideration of correlativity between litho and etching shape

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

2012-03-01

We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

Wing shape and size of the western corn rootworm (Coleoptera: Chrysomelidae) is related to sex and resistance to soybean-maize crop rotation.

PubMed

Mikac, K M; Douglas, J; Spencer, J L

2013-08-01

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of maize in the United States and more recently, Europe. Understanding the dispersal dynamics of this species will provide crucial information for its management. This study used geometric morphometric analysis of hind wing venation based on 13 landmarks in 223 specimens from nine locations in Illinois, Nebraska, Iowa, and Missouri, to assess whether wing shape and size differed between rotated and continuously grown maize where crop rotation-resistant and susceptible individuals are found, respectively. Before assessing differences between rotation-resistant and susceptible individuals, sexual dimorphism was investigated. No significant difference in wing (centroid) size was found between males and females; however, females had significantly different shaped (more elongated) wings compared with males. Wing shape and (centroid) size were significantly larger among individuals from rotated maize where crop-rotation resistance was reported; however, cross-validation of these results revealed that collection site resistance status was an only better than average predictor of shape in males and females. This study provides preliminary evidence of wing shape and size differences in D. v. virgifera from rotated versus continuous maize. Further study is needed to confirm whether wing shape and size can be used to track the movement of rotation-resistant individuals and populations as a means to better inform management strategies.

A Three-Dimensional Analysis of Morphological Evolution and Locomotor Performance of the Carnivoran Forelimb

PubMed Central

Martín-Serra, Alberto; Figueirido, Borja; Palmqvist, Paul

2014-01-01

In this study, three-dimensional landmark-based methods of geometric morphometrics are used for estimating the influence of phylogeny, allometry and locomotor performance on forelimb shape in living and extinct carnivorans (Mammalia, Carnivora). The main objective is to investigate morphological convergences towards similar locomotor strategies in the shape of the major forelimb bones. Results indicate that both size and phylogeny have strong effects on the anatomy of all forelimb bones. In contrast, bone shape does not correlate in the living taxa with maximum running speed or daily movement distance, two proxies closely related to locomotor performance. A phylomorphospace approach showed that shape variation in forelimb bones mainly relates to changes in bone robustness. This indicates the presence of biomechanical constraints resulting from opposite demands for energetic efficiency in locomotion –which would require a slender forelimb– and resistance to stress –which would be satisfied by a robust forelimb–. Thus, we interpret that the need of maintaining a trade-off between both functional demands would limit shape variability in forelimb bones. Given that different situations can lead to one or another morphological solution, depending on the specific ecology of taxa, the evolution of forelimb morphology represents a remarkable “one-to-many mapping” case between anatomy and ecology. PMID:24454891

Effects of thermo-mechanical behavior and hinge geometry on folding response of shape memory polymer sheets

NASA Astrophysics Data System (ADS)

Mailen, Russell W.; Dickey, Michael D.; Genzer, Jan; Zikry, Mohammed

2017-11-01

Shape memory polymer (SMP) sheets patterned with black ink hinges change shape in response to external stimuli, such as absorbed thermal energy from an infrared (IR) light. The geometry of these hinges, including size, orientation, and location, and the applied thermal loads significantly influence the final folded shape of the sheet, but these variables have not been fully investigated. We perform a systematic study on SMP sheets to fundamentally understand the effects of single and double hinge geometries, hinge orientation and spacing, initial temperature, heat flux intensity, and pattern width on the folding behavior. We have developed thermo-viscoelastic finite element models to characterize and quantify the stresses, strains, and temperatures as they relate to SMP shape changes. Our predictions indicate that hinge orientation can be used to reduce the total bending angle, which is the angle traversed by the folding face of the sheet. Two parallel hinges increase the total bending angle, and heat conduction between the hinges affects the transient folding response. IR intensity and initial temperatures can also influence the transient folding behavior. These results can provide guidelines to optimize the transient folding response and the three-dimensional folded structure obtained from self-folding polymer origami sheets that can be applied for myriad applications.

Ultrasonographic Evaluation of Cervical Lymph Nodes in Thyroid Cancer.

PubMed

Machado, Maria Regina Marrocos; Tavares, Marcos Roberto; Buchpiguel, Carlos Alberto; Chammas, Maria Cristina

2017-02-01

Objective To determine what ultrasonographic features can identify metastatic cervical lymph nodes, both preoperatively and in recurrences after complete thyroidectomy. Study Design Prospective. Setting Outpatient clinic, Department of Head and Neck Surgery, School of Medicine, University of São Paulo, Brazil. Subjects and Methods A total of 1976 lymph nodes were evaluated in 118 patients submitted to total thyroidectomy with or without cervical lymph node dissection. All the patients were examined by cervical ultrasonography, preoperatively and/or postoperatively. The following factors were assessed: number, size, shape, margins, presence of fatty hilum, cortex, echotexture, echogenicity, presence of microcalcification, presence of necrosis, and type of vascularity. The specificity, sensitivity, positive predictive value, and negative predictive value of each variable were calculated. Univariate and multivariate logistic regression analyses were conducted. A receiver operator characteristic (ROC) curve was plotted to determine the best cutoff value for the number of variables to discriminate malignant lymph nodes. Results Significant differences were found between metastatic and benign lymph nodes with regard to all of the variables evaluated ( P < .05). Logistic regression analysis revealed that size and echogenicity were the best combination of altered variables (odds ratio, 40.080 and 7.288, respectively) in discriminating malignancy. The ROC curve analysis showed that 4 was the best cutoff value for the number of altered variables to discriminate malignant lymph nodes, with a combined specificity of 85.7%, sensitivity of 96.4%, and efficiency of 91.0%. Conclusion Greater diagnostic accuracy was achieved by associating the ultrasonographic variables assessed rather than by considering them individually.

Baselines and null hypotheses for climate change: Phytoplankton biomass structure in the California Current

NASA Astrophysics Data System (ADS)

Landry, M. R.; Taylor, A. G.

2016-02-01

Phytoplankton community structure is shaped both by the bottom-up influences of the physical-chemical environment and by the top-down impacts of food webs. Emergent patterns in the contemporary ocean can thus be "null hypotheses" of future changes assuming that the underlying structuring relationships remain intact but only shift spatially. To provide such a context for the California Current Ecosystem (CCE) and adjacent open-ocean ecosystems, we used a combination of digital epifluorescence microscopy and flow cytometry to investigate variability of phytoplankton biomass, composition and size structure across gradients of ecosystem richness, as represented by total autotrophic carbon (AC). Biomass of large micro-sized (>20 µm) phytoplankton increases as a power function with system richness. Nano-sized cells (2-20 µm) increase at a lower rate at low AC, and level off at high AC. Pico-sized cells (<2-µm) do not clearly dominate at low AC and decline significantly at high AC, neither predicted by competition theory. This study provides several new insights into structural relationships and mechanisms in the CCE: 1) diatoms and dinoflagellates co-dominate the micro-phytoplankton size class throughout the range of system richness; 2) nano-phytoplankton co-dominate biomass in oligotrophic (low AC) waters, suggesting widespread mixotrophy rather than direct competition with pico-phytoplankton for nutrients; and 3) the pico-phytoplankton decline at high AC impacts small eukaryotes as well as photosynthetic bacteria, consistent with a broad stimulation of grazing pressure on all bacterial-sized cells in richer systems. Observed variability in heterotrophic bacteria and nano-flagellate grazers with system richness is consistent with this mechanism.

Facial Shape Analysis Identifies Valid Cues to Aspects of Physiological Health in Caucasian, Asian, and African Populations.

PubMed

Stephen, Ian D; Hiew, Vivian; Coetzee, Vinet; Tiddeman, Bernard P; Perrett, David I

2017-01-01

Facial cues contribute to attractiveness, including shape cues such as symmetry, averageness, and sexual dimorphism. These cues may represent cues to objective aspects of physiological health, thereby conferring an evolutionary advantage to individuals who find them attractive. The link between facial cues and aspects of physiological health is therefore central to evolutionary explanations of attractiveness. Previously, studies linking facial cues to aspects of physiological health have been infrequent, have had mixed results, and have tended to focus on individual facial cues in isolation. Geometric morphometric methodology (GMM) allows a bottom-up approach to identifying shape correlates of aspects of physiological health. Here, we apply GMM to facial shape data, producing models that successfully predict aspects of physiological health in 272 Asian, African, and Caucasian faces - percentage body fat (21.0% of variance explained), body mass index (BMI; 31.9%) and blood pressure (BP; 21.3%). Models successfully predict percentage body fat and blood pressure even when controlling for BMI, suggesting that they are not simply measuring body size. Predicted values of BMI and BP, but not percentage body fat, correlate with health ratings. When asked to manipulate the shape of faces along the physiological health variable axes (as determined by the models), participants reduced predicted BMI, body fat and (marginally) BP, suggesting that facial shape provides a valid cue to aspects of physiological health.

Facial Shape Analysis Identifies Valid Cues to Aspects of Physiological Health in Caucasian, Asian, and African Populations

PubMed Central

Stephen, Ian D.; Hiew, Vivian; Coetzee, Vinet; Tiddeman, Bernard P.; Perrett, David I.

2017-01-01

Facial cues contribute to attractiveness, including shape cues such as symmetry, averageness, and sexual dimorphism. These cues may represent cues to objective aspects of physiological health, thereby conferring an evolutionary advantage to individuals who find them attractive. The link between facial cues and aspects of physiological health is therefore central to evolutionary explanations of attractiveness. Previously, studies linking facial cues to aspects of physiological health have been infrequent, have had mixed results, and have tended to focus on individual facial cues in isolation. Geometric morphometric methodology (GMM) allows a bottom–up approach to identifying shape correlates of aspects of physiological health. Here, we apply GMM to facial shape data, producing models that successfully predict aspects of physiological health in 272 Asian, African, and Caucasian faces – percentage body fat (21.0% of variance explained), body mass index (BMI; 31.9%) and blood pressure (BP; 21.3%). Models successfully predict percentage body fat and blood pressure even when controlling for BMI, suggesting that they are not simply measuring body size. Predicted values of BMI and BP, but not percentage body fat, correlate with health ratings. When asked to manipulate the shape of faces along the physiological health variable axes (as determined by the models), participants reduced predicted BMI, body fat and (marginally) BP, suggesting that facial shape provides a valid cue to aspects of physiological health. PMID:29163270

The Interannual Stability of Cumulative Frequency Distributions for Convective System Size and Intensity

NASA Technical Reports Server (NTRS)

Mohr, Karen I.; Molinari, John; Thorncroft, Chris D,

2010-01-01

The characteristics of convective system populations in West Africa and the western Pacific tropical cyclone basin were analyzed to investigate whether interannual variability in convective activity in tropical continental and oceanic environments is driven by variations in the number of events during the wet season or by favoring large and/or intense convective systems. Convective systems were defined from TRMM data as a cluster of pixels with an 85 GHz polarization-corrected brightness temperature below 255 K and with an area at least 64 km 2. The study database consisted of convective systems in West Africa from May Sep for 1998-2007 and in the western Pacific from May Nov 1998-2007. Annual cumulative frequency distributions for system minimum brightness temperature and system area were constructed for both regions. For both regions, there were no statistically significant differences among the annual curves for system minimum brightness temperature. There were two groups of system area curves, split by the TRMM altitude boost in 2001. Within each set, there was no statistically significant interannual variability. Sub-setting the database revealed some sensitivity in distribution shape to the size of the sampling area, length of sample period, and climate zone. From a regional perspective, the stability of the cumulative frequency distributions implied that the probability that a convective system would attain a particular size or intensity does not change interannually. Variability in the number of convective events appeared to be more important in determining whether a year is wetter or drier than normal.

Modeling Linguistic Variables With Regression Models: Addressing Non-Gaussian Distributions, Non-independent Observations, and Non-linear Predictors With Random Effects and Generalized Additive Models for Location, Scale, and Shape

PubMed Central

Coupé, Christophe

2018-01-01

As statistical approaches are getting increasingly used in linguistics, attention must be paid to the choice of methods and algorithms used. This is especially true since they require assumptions to be satisfied to provide valid results, and because scientific articles still often fall short of reporting whether such assumptions are met. Progress is being, however, made in various directions, one of them being the introduction of techniques able to model data that cannot be properly analyzed with simpler linear regression models. We report recent advances in statistical modeling in linguistics. We first describe linear mixed-effects regression models (LMM), which address grouping of observations, and generalized linear mixed-effects models (GLMM), which offer a family of distributions for the dependent variable. Generalized additive models (GAM) are then introduced, which allow modeling non-linear parametric or non-parametric relationships between the dependent variable and the predictors. We then highlight the possibilities offered by generalized additive models for location, scale, and shape (GAMLSS). We explain how they make it possible to go beyond common distributions, such as Gaussian or Poisson, and offer the appropriate inferential framework to account for ‘difficult’ variables such as count data with strong overdispersion. We also demonstrate how they offer interesting perspectives on data when not only the mean of the dependent variable is modeled, but also its variance, skewness, and kurtosis. As an illustration, the case of phonemic inventory size is analyzed throughout the article. For over 1,500 languages, we consider as predictors the number of speakers, the distance from Africa, an estimation of the intensity of language contact, and linguistic relationships. We discuss the use of random effects to account for genealogical relationships, the choice of appropriate distributions to model count data, and non-linear relationships. Relying on GAMLSS, we assess a range of candidate distributions, including the Sichel, Delaporte, Box-Cox Green and Cole, and Box-Cox t distributions. We find that the Box-Cox t distribution, with appropriate modeling of its parameters, best fits the conditional distribution of phonemic inventory size. We finally discuss the specificities of phoneme counts, weak effects, and how GAMLSS should be considered for other linguistic variables. PMID:29713298

Modeling Linguistic Variables With Regression Models: Addressing Non-Gaussian Distributions, Non-independent Observations, and Non-linear Predictors With Random Effects and Generalized Additive Models for Location, Scale, and Shape.

PubMed

Coupé, Christophe

2018-01-01

As statistical approaches are getting increasingly used in linguistics, attention must be paid to the choice of methods and algorithms used. This is especially true since they require assumptions to be satisfied to provide valid results, and because scientific articles still often fall short of reporting whether such assumptions are met. Progress is being, however, made in various directions, one of them being the introduction of techniques able to model data that cannot be properly analyzed with simpler linear regression models. We report recent advances in statistical modeling in linguistics. We first describe linear mixed-effects regression models (LMM), which address grouping of observations, and generalized linear mixed-effects models (GLMM), which offer a family of distributions for the dependent variable. Generalized additive models (GAM) are then introduced, which allow modeling non-linear parametric or non-parametric relationships between the dependent variable and the predictors. We then highlight the possibilities offered by generalized additive models for location, scale, and shape (GAMLSS). We explain how they make it possible to go beyond common distributions, such as Gaussian or Poisson, and offer the appropriate inferential framework to account for 'difficult' variables such as count data with strong overdispersion. We also demonstrate how they offer interesting perspectives on data when not only the mean of the dependent variable is modeled, but also its variance, skewness, and kurtosis. As an illustration, the case of phonemic inventory size is analyzed throughout the article. For over 1,500 languages, we consider as predictors the number of speakers, the distance from Africa, an estimation of the intensity of language contact, and linguistic relationships. We discuss the use of random effects to account for genealogical relationships, the choice of appropriate distributions to model count data, and non-linear relationships. Relying on GAMLSS, we assess a range of candidate distributions, including the Sichel, Delaporte, Box-Cox Green and Cole, and Box-Cox t distributions. We find that the Box-Cox t distribution, with appropriate modeling of its parameters, best fits the conditional distribution of phonemic inventory size. We finally discuss the specificities of phoneme counts, weak effects, and how GAMLSS should be considered for other linguistic variables.

Shape and size variation on the wing of Drosophila mediopunctata: influence of chromosome inversions and genotype-environment interaction.

PubMed

Hatadani, Luciane Mendes; Klaczko, Louis Bernard

2008-07-01

The second chromosome of Drosophila mediopunctata is highly polymorphic for inversions. Previous work reported a significant interaction between these inversions and collecting date on wing size, suggesting the presence of genotype-environment interaction. We performed experiments in the laboratory to test for the joint effects of temperature and chromosome inversions on size and shape of the wing in D. mediopunctata. Size was measured as the centroid size, and shape was analyzed using the generalized least squares Procrustes superimposition followed by discriminant analysis and canonical variates analysis of partial warps and uniform components scores. Our findings show that wing size and shape are influenced by temperature, sex, and karyotype. We also found evidence suggestive of an interaction between the effects of karyotype and temperature on wing shape, indicating the existence of genotype-environment interaction for this trait in D. mediopunctata. In addition, the association between wing size and chromosome inversions is in agreement with previous results indicating that these inversions might be accumulating alleles adapted to different temperatures. However, no significant interaction between temperature and karyotype for size was found--in spite of the significant presence of temperature-genotype (cross) interaction. We suggest that other ecological factors--such as larval crowding--or seasonal variation of genetic content within inversions may explain the previous results.

Comparison of Two Methods Used to Model Shape Parameters of Pareto Distributions

USGS Publications Warehouse

Liu, C.; Charpentier, R.R.; Su, J.

2011-01-01

Two methods are compared for estimating the shape parameters of Pareto field-size (or pool-size) distributions for petroleum resource assessment. Both methods assume mature exploration in which most of the larger fields have been discovered. Both methods use the sizes of larger discovered fields to estimate the numbers and sizes of smaller fields: (1) the tail-truncated method uses a plot of field size versus size rank, and (2) the log-geometric method uses data binned in field-size classes and the ratios of adjacent bin counts. Simulation experiments were conducted using discovered oil and gas pool-size distributions from four petroleum systems in Alberta, Canada and using Pareto distributions generated by Monte Carlo simulation. The estimates of the shape parameters of the Pareto distributions, calculated by both the tail-truncated and log-geometric methods, generally stabilize where discovered pool numbers are greater than 100. However, with fewer than 100 discoveries, these estimates can vary greatly with each new discovery. The estimated shape parameters of the tail-truncated method are more stable and larger than those of the log-geometric method where the number of discovered pools is more than 100. Both methods, however, tend to underestimate the shape parameter. Monte Carlo simulation was also used to create sequences of discovered pool sizes by sampling from a Pareto distribution with a discovery process model using a defined exploration efficiency (in order to show how biased the sampling was in favor of larger fields being discovered first). A higher (more biased) exploration efficiency gives better estimates of the Pareto shape parameters. ?? 2011 International Association for Mathematical Geosciences.

The effect of particle shape and size distribution on the acoustical properties of mixtures of hemp particles.

PubMed

Glé, Philippe; Gourdon, Emmanuel; Arnaud, Laurent; Horoshenkov, Kirill-V; Khan, Amir

2013-12-01

Hemp concrete is an attractive alternative to traditional materials used in building construction. It has a very low environmental impact, and it is characterized by high thermal insulation. Hemp aggregate particles are parallelepiped in shape and can be organized in a plurality of ways to create a considerable proportion of open pores with a complex connectivity pattern, the acoustical properties of which have never been examined systematically. Therefore this paper is focused on the fundamental understanding of the relations between the particle shape and size distribution, pore size distribution, and the acoustical properties of the resultant porous material mixture. The sound absorption and the transmission loss of various hemp aggregates is characterized using laboratory experiments and three theoretical models. These models are used to relate the particle size distribution to the pore size distribution. It is shown that the shape of particles and particle size control the pore size distribution and tortuosity in shiv. These properties in turn relate directly to the observed acoustical behavior.

Impact of Snow Grain Shape and Internal Mixing with Black Carbon Aerosol on Snow Optical Properties for use in Climate Models

NASA Astrophysics Data System (ADS)

He, C.; Liou, K. N.; Takano, Y.; Yang, P.; Li, Q.; Chen, F.

2017-12-01

A set of parameterizations is developed for spectral single-scattering properties of clean and black carbon (BC)-contaminated snow based on geometric-optic surface-wave (GOS) computations, which explicitly resolves BC-snow internal mixing and various snow grain shapes. GOS calculations show that, compared with nonspherical grains, volume-equivalent snow spheres show up to 20% larger asymmetry factors and hence stronger forward scattering, particularly at wavelengths <1 mm. In contrast, snow grain sizes have a rather small impact on the asymmetry factor at wavelengths <1 mm, whereas size effects are important at longer wavelengths. The snow asymmetry factor is parameterized as a function of effective size, aspect ratio, and shape factor, and shows excellent agreement with GOS calculations. According to GOS calculations, the single-scattering coalbedo of pure snow is predominantly affected by grain sizes, rather than grain shapes, with higher values for larger grains. The snow single-scattering coalbedo is parameterized in terms of the effective size that combines shape and size effects, with an accuracy of >99%. Based on GOS calculations, BC-snow internal mixing enhances the snow single-scattering coalbedo at wavelengths <1 mm, but it does not alter the snow asymmetry factor. The BC-induced enhancement ratio of snow single-scattering coalbedo, independent of snow grain size and shape, is parameterized as a function of BC concentration with an accuracy of >99%. Overall, in addition to snow grain size, both BC-snow internal mixing and snow grain shape play critical roles in quantifying BC effects on snow optical properties. The present parameterizations can be conveniently applied to snow, land surface, and climate models including snowpack radiative transfer processes.

Size and shape effects in β-NaGdF4: Yb3+, Er3+ nanocrystals

NASA Astrophysics Data System (ADS)

Noculak, Agnieszka; Podhorodecki, Artur

2017-04-01

Three sets of β-NaGdF4:Yb3+, Er3+ nanocrystals (NCs) with different shapes (spherical and more complex flower shapes), different sizes (6-17 nm) and Yb3+ concentrations (2%-15%) were synthesized by a co-precipitation method using oleic acid as a stabilizing agent. The uncommon, single-crystalline flower-shaped NCs were obtained by simply adjusting the fluorine-to-lanthanides molar ratio. Additionally, some of the NCs with different sizes have been covered by the un-doped shell. The crystal phase, shapes and sizes of all NCs were examined using transmission electron microscopy and x-ray diffraction methods. Simultaneously, upconversion luminescence and lifetimes, under 980 nm excitation, were measured and the changes in green to red (G/R) emission ratios as well as emission decay times were correlated with the evolution of nanocrystal sizes and surface to volume ratios. Three different mechanisms responsible for the changes in G/R ratios were presented and discussed.

Rostro-dorsal and rostro-lateral skull morphologic variability in three age-groups of the Egyptian mongoose (Herpestes ichneumon) (Linnaeus, 1758): implications of certain orbital parameters - angular geometric approach.

PubMed

Samuel, M O; Wanmi, N; Usende, L

2016-01-01

This study evaluated 30 skulls of the grey mongoose divided into three age-groups (6 pups, 10 juveniles and 14 adults) for skull shape variability determination. Specific geometric shapes were drawn from defined points. Angular geometric measurements of shapes derived from rostro-dorsal and rostro-lateral parts of the skull included; orbital angles (with and without the mandible), comprising of viscero-cranium, skull and orbital index that was calculated to evaluate the correlations, if any, with angles measured. It was observed that orbital height and width became higher with age; there was stronger correlation in this regard between pups and juveniles compared with juveniles and adults. There is a reduction (narrowing) in BrEcEc, BrEcN, EcPEc, EcEnN and NwNNw angles with concomitant enlargement of BrEcP, BrEcN, EcNEc, EnNEn, EcNNw and EnNP with age. The decline in the skull index shows a decrease in rate of skull width growth relative to rostro-facial length and demonstrates non-proportionality to zygoma bowing. Significantly varied orbital parameters include the inter-canthii distance and implications of certain significant variables observed in some geometric orbital measurements of the tropical mongoose (Herpestes ichneumon). The survey hypothesizes the observations follow typical carnivoran phylogenic affinity, differentiates this species from similar herpestid versions and is an estimation of functional morphology with respect to bite size. It is further suggested to contribute to visual acuity in timing of bite delivery as well an adaptation in prey summarisation. This study will serve as baseline information in herpestid cranial investigations. Such facial features are useful in population studies, species identification, eco-migrant species surveillance and species ontogenic evolution.

Settling equivalence of detrital minerals and grain-size dependence of sediment composition

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni

2008-08-01

This study discusses the laws which govern sediment deposition, and consequently determine size-dependent compositional variability. A theoretical approach is substantiated by robust datasets on major Alpine, Himalayan, and African sedimentary systems. Integrated (bulk-petrography, heavy-mineral, X-ray powder diffraction) multiple-window analyses at 0.25ϕ to 0.50ϕ sieve interval of eighty-five fluvial, beach, and eolian-dune samples, ranging from very fine silt to coarse sand, document homologous intrasample compositional trends, revealed by systematic concentration of denser grains in finer-grained fractions (“size-density sorting”). These trends are explained by the settling-equivalence principle, stating that detrital minerals are deposited together if their settling velocity is the same. Settling of silt is chiefly resisted by fluid viscosity, and Stokes' law predicts that size differences between detrital minerals in ϕ units (“size shifts”) are half the difference between the logarithms of their submerged densities. Settling of pebbles is chiefly resisted by turbulence effects, and the Impact law predicts double size shifts than Stokes' law. Settling of sand is resisted by both viscosity and turbulence, the settling-equivalence formula is complex, and size shifts increase - with increasing settling velocity and grain size - from those predicted by Stokes' law to those predicted by the Impact law. In wind-laid sands, size shifts match those predicted by the Impact law; size-density sorting is thus greater than in water-laid fine sands. New analytical, graphical, and statistical techniques for rigorous settling-equivalence analysis of terrigenous sediments are illustrated. Deviations associated with non-spherical shape, density anomalies, inheritance from source rocks, or mixing of detrital species with contrasting provenance and different size distribution are also tentatively assessed. Such integrated theoretical and experimental approach allows us to mathematically predict intrasample compositional variability of water-laid and wind-laid sediments, once the density of detrital components is known.

Does skull morphology constrain bone ornamentation? A morphometric analysis in the Crocodylia.

PubMed

Clarac, F; Souter, T; Cubo, J; de Buffrénil, V; Brochu, C; Cornette, R

2016-08-01

Previous quantitative assessments of the crocodylians' dermal bone ornamentation (this ornamentation consists of pits and ridges) has shown that bone sculpture results in a gain in area that differs between anatomical regions: it tends to be higher on the skull table than on the snout. Therefore, a comparative phylogenetic analysis within 17 adult crocodylian specimens representative of the morphological diversity of the 24 extant species has been performed, in order to test if the gain in area due to ornamentation depends on the skull morphology, i.e. shape and size. Quantitative assessment of skull size and shape through geometric morphometrics, and of skull ornamentation through surface analyses, produced a dataset that was analyzed using phylogenetic least-squares regression. The analyses reveal that none of the variables that quantify ornamentation, be they on the snout or the skull table, is correlated with the size of the specimens. Conversely, there is more disparity in the relationships between skull conformations (longirostrine vs. brevirostrine) and ornamentation. Indeed, both parameters GApit (i.e. pit depth and shape) and OArelat (i.e. relative area of the pit set) are negatively correlated with snout elongation, whereas none of the values quantifying ornamentation on the skull table is correlated with skull conformation. It can be concluded that bone sculpture on the snout is influenced by different developmental constrains than on the skull table and is sensible to differences in the local growth 'context' (allometric processes) prevailing in distinct skull parts. Whatever the functional role of bone ornamentation on the skull, if any, it seems to be restricted to some anatomical regions at least for the longirostrine forms that tend to lose ornamentation on the snout. © 2016 Anatomical Society.

Mechanisms shaping size structure and functional diversity of phytoplankton communities in the ocean

PubMed Central

Acevedo-Trejos, Esteban; Brandt, Gunnar; Bruggeman, Jorn; Merico, Agostino

2015-01-01

The factors regulating phytoplankton community composition play a crucial role in structuring aquatic food webs. However, consensus is still lacking about the mechanisms underlying the observed biogeographical differences in cell size composition of phytoplankton communities. Here we use a trait-based model to disentangle these mechanisms in two contrasting regions of the Atlantic Ocean. In our model, the phytoplankton community can self-assemble based on a trade-off emerging from relationships between cell size and (1) nutrient uptake, (2) zooplankton grazing, and (3) phytoplankton sinking. Grazing ‘pushes’ the community towards larger cell sizes, whereas nutrient uptake and sinking ‘pull’ the community towards smaller cell sizes. We find that the stable environmental conditions of the tropics strongly balance these forces leading to persistently small cell sizes and reduced size diversity. In contrast, the seasonality of the temperate region causes the community to regularly reorganize via shifts in species composition and to exhibit, on average, bigger cell sizes and higher size diversity than in the tropics. Our results raise the importance of environmental variability as a key structuring mechanism of plankton communities in the ocean and call for a reassessment of the current understanding of phytoplankton diversity patterns across latitudinal gradients. PMID:25747280

Morpho morphometrics: Shared ancestry and selection drive the evolution of wing size and shape in Morpho butterflies.

PubMed

Chazot, Nicolas; Panara, Stephen; Zilbermann, Nicolas; Blandin, Patrick; Le Poul, Yann; Cornette, Raphaël; Elias, Marianne; Debat, Vincent

2016-01-01

Butterfly wings harbor highly diverse phenotypes and are involved in many functions. Wing size and shape result from interactions between adaptive processes, phylogenetic history, and developmental constraints, which are complex to disentangle. Here, we focus on the genus Morpho (Nymphalidae: Satyrinae, 30 species), which presents a high diversity of sizes, shapes, and color patterns. First, we generate a comprehensive molecular phylogeny of these 30 species. Next, using 911 collection specimens, we quantify the variation of wing size and shape across species, to assess the importance of shared ancestry, microhabitat use, and sexual selection in the evolution of the wings. While accounting for phylogenetic and allometric effects, we detect a significant difference in wing shape but not size among microhabitats. Fore and hindwings covary at the individual and species levels, and the covariation differs among microhabitats. However, the microhabitat structure in covariation disappears when phylogenetic relationships are taken into account. Our results demonstrate that microhabitat has driven wing shape evolution, although it has not strongly affected forewing and hindwing integration. We also found that sexual dimorphism of forewing shape and color pattern are coupled, suggesting a common selective force. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Fourier analysis of human soft tissue facial shape: sex differences in normal adults.

PubMed Central

Ferrario, V F; Sforza, C; Schmitz, J H; Miani, A; Taroni, G

1995-01-01

Sexual dimorphism in human facial form involves both size and shape variations of the soft tissue structures. These variations are conventionally appreciated using linear and angular measurements, as well as ratios, taken from photographs or radiographs. Unfortunately this metric approach provides adequate quantitative information about size only, eluding the problems of shape definition. Mathematical methods such as the Fourier series allow a correct quantitative analysis of shape and of its changes. A method for the reconstruction of outlines starting from selected landmarks and for their Fourier analysis has been developed, and applied to analyse sex differences in shape of the soft tissue facial contour in a group of healthy young adults. When standardised for size, no sex differences were found between both cosine and sine coefficients of the Fourier series expansion. This shape similarity was largely overwhelmed by the very evident size differences and it could be measured only using the proper mathematical methods. PMID:8586558

Extrusion-spheronization: process variables and characterization.

PubMed

Sinha, V R; Agrawal, M K; Agarwal, A; Singh, G; Ghai, D

2009-01-01

Multiparticulate systems have undergone great development in the past decade fueled by the better understanding of their multiple roles as a suitable delivery system. With the passage of time, significant advances have been made in the process of pelletization due to the incorporation of specialized techniques for their development. Extrusion-spheronization seems to be the most promising process for the optimum delivery of many potent drugs having high systemic toxicity. It also offers immense pharmaceutical applicability due to the benefits of high loading capacity of active ingredient(s), narrow size distribution, and cost-effectiveness. On application of a specific coat, these systems can also aid in site-specific delivery, thereby enhancing the bioavailability of many drugs. The current review focuses on the process of extrusion-spheronization and the operational (extruder types, screen pressure, screw speed, temperature, moisture content, spheronization load, speed and time) and formulation (excipients and drugs) variables, which may affect the quality of the final pellets. Various methods for the evaluation of the quality of the pellets with regard to the size distribution, shape, friability, granule strength, density, porosity, flow properties, and surface texture are discussed.

Simultaneous Aerodynamic and Structural Design Optimization (SASDO) for a 3-D Wing

NASA Technical Reports Server (NTRS)

Gumbert, Clyde R.; Hou, Gene J.-W.; Newman, Perry A.

2001-01-01

The formulation and implementation of an optimization method called Simultaneous Aerodynamic and Structural Design Optimization (SASDO) is shown as an extension of the Simultaneous Aerodynamic Analysis and Design Optimization (SAADO) method. It is extended by the inclusion of structure element sizing parameters as design variables and Finite Element Method (FEM) analysis responses as constraints. The method aims to reduce the computational expense. incurred in performing shape and sizing optimization using state-of-the-art Computational Fluid Dynamics (CFD) flow analysis, FEM structural analysis and sensitivity analysis tools. SASDO is applied to a simple. isolated, 3-D wing in inviscid flow. Results show that the method finds the saine local optimum as a conventional optimization method with some reduction in the computational cost and without significant modifications; to the analysis tools.

Karyotyping human chromosomes by optical and x-ray ptychography methods

DOE PAGES

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg; ...

2015-02-01

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Karyotyping human chromosomes by optical and x-ray ptychography methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Quantitative analysis of fetal facial morphology using 3D ultrasound and statistical shape modeling: a feasibility study.

PubMed

Dall'Asta, Andrea; Schievano, Silvia; Bruse, Jan L; Paramasivam, Gowrishankar; Kaihura, Christine Tita; Dunaway, David; Lees, Christoph C

2017-07-01

The antenatal detection of facial dysmorphism using 3-dimensional ultrasound may raise the suspicion of an underlying genetic condition but infrequently leads to a definitive antenatal diagnosis. Despite advances in array and noninvasive prenatal testing, not all genetic conditions can be ascertained from such testing. The aim of this study was to investigate the feasibility of quantitative assessment of fetal face features using prenatal 3-dimensional ultrasound volumes and statistical shape modeling. STUDY DESIGN: Thirteen normal and 7 abnormal stored 3-dimensional ultrasound fetal face volumes were analyzed, at a median gestation of 29 +4  weeks (25 +0 to 36 +1 ). The 20 3-dimensional surface meshes generated were aligned and served as input for a statistical shape model, which computed the mean 3-dimensional face shape and 3-dimensional shape variations using principal component analysis. Ten shape modes explained more than 90% of the total shape variability in the population. While the first mode accounted for overall size differences, the second highlighted shape feature changes from an overall proportionate toward a more asymmetric face shape with a wide prominent forehead and an undersized, posteriorly positioned chin. Analysis of the Mahalanobis distance in principal component analysis shape space suggested differences between normal and abnormal fetuses (median and interquartile range distance values, 7.31 ± 5.54 for the normal group vs 13.27 ± 9.82 for the abnormal group) (P = .056). This feasibility study demonstrates that objective characterization and quantification of fetal facial morphology is possible from 3-dimensional ultrasound. This technique has the potential to assist in utero diagnosis, particularly of rare conditions in which facial dysmorphology is a feature. Copyright © 2017 Elsevier Inc. All rights reserved.

A Field Study of Pixel-Scale Variability of Raindrop Size Distribution in the MidAtlantic Region

NASA Technical Reports Server (NTRS)

Tokay, Ali; D'adderio, Leo Pio; Wolff, David P.; Petersen, Walter A.

2016-01-01

The spatial variability of parameters of the raindrop size distribution and its derivatives is investigated through a field study where collocated Particle Size and Velocity (Parsivel2) and two-dimensional video disdrometers were operated at six sites at Wallops Flight Facility, Virginia, from December 2013 to March 2014. The three-parameter exponential function was employed to determine the spatial variability across the study domain where the maximum separation distance was 2.3 km. The nugget parameter of the exponential function was set to 0.99 and the correlation distance d0 and shape parameter s0 were retrieved by minimizing the root-mean-square error, after fitting it to the correlations of physical parameters. Fits were very good for almost all 15 physical parameters. The retrieved d0 and s0 were about 4.5 km and 1.1, respectively, for rain rate (RR) when all 12 disdrometers were reporting rainfall with a rain-rate threshold of 0.1 mm h1 for 1-min averages. The d0 decreased noticeably when one or more disdrometers were required to report rain. The d0 was considerably different for a number of parameters (e.g., mass-weighted diameter) but was about the same for the other parameters (e.g., RR) when rainfall threshold was reset to 12 and 18 dBZ for Ka- and Ku-band reflectivity, respectively, following the expected Global Precipitation Measurement missions spaceborne radar minimum detectable signals. The reduction of the database through elimination of a site did not alter d0 as long as the fit was adequate. The correlations of 5-min rain accumulations were lower when disdrometer observations were simulated for a rain gauge at different bucket sizes.

Effect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model

USGS Publications Warehouse

Ganju, Neil K.; Sherwood, Christopher R.

2010-01-01

A variety of algorithms are available for parameterizing the hydrodynamic bottom roughness associated with grain size, saltation, bedforms, and wave–current interaction in coastal ocean models. These parameterizations give rise to spatially and temporally variable bottom-drag coefficients that ostensibly provide better representations of physical processes than uniform and constant coefficients. However, few studies have been performed to determine whether improved representation of these variable bottom roughness components translates into measurable improvements in model skill. We test the hypothesis that improved representation of variable bottom roughness improves performance with respect to near-bed circulation, bottom stresses, or turbulence dissipation. The inner shelf south of Martha’s Vineyard, Massachusetts, is the site of sorted grain-size features which exhibit sharp alongshore variations in grain size and ripple geometry over gentle bathymetric relief; this area provides a suitable testing ground for roughness parameterizations. We first establish the skill of a nested regional model for currents, waves, stresses, and turbulent quantities using a uniform and constant roughness; we then gauge model skill with various parameterization of roughness, which account for the influence of the wave-boundary layer, grain size, saltation, and rippled bedforms. We find that commonly used representations of ripple-induced roughness, when combined with a wave–current interaction routine, do not significantly improve skill for circulation, and significantly decrease skill with respect to stresses and turbulence dissipation. Ripple orientation with respect to dominant currents and ripple shape may be responsible for complicating a straightforward estimate of the roughness contribution from ripples. In addition, sediment-induced stratification may be responsible for lower stresses than predicted by the wave–current interaction model.

Variation in the shape and mechanical performance of the lower jaws in ceratopsid dinosaurs (Ornithischia, Ceratopsia).

PubMed

Maiorino, Leonardo; Farke, Andrew A; Kotsakis, Tassos; Teresi, Luciano; Piras, Paolo

2015-11-01

Ceratopsidae represents a group of quadrupedal herbivorous dinosaurs that inhabited western North America and eastern Asia during the Late Cretaceous. Although horns and frills of the cranium are highly variable across species, the lower jaw historically has been considered to be relatively conservative in morphology. Here, the lower jaws from 58 specimens representing 21 ceratopsoid taxa were sampled, using geometric morphometrics and 2D finite element analysis (FEA) to explore differences in morphology and mechanical performance across Ceratopsoidea (the clade including Ceratopsidae, Turanoceratops and Zuniceratops). Principal component analyses and non-parametric permuted manovas highlight Triceratopsini as a morphologically distinct clade within the sample. A relatively robust and elongate dentary, a larger and more elongated coronoid process, and a small and dorso-ventrally compressed angular characterize this clade, as well as the absolutely larger size. By contrast, non-triceratopsin chasmosaurines, Centrosaurini and Pachyrhinosaurini have similar morphologies to each other. Zuniceratops and Avaceratops are distinct from other taxa. No differences in size between Pachyrhinosaurini and Centrosaurini are recovered using non-parametric permuted anovas. Structural performance, as evaluated using a 2D FEA, is similar across all groups as measured by overall stress, with the exception of Triceratopsini. Shape, size and stress are phylogenetically constrained. A longer dentary as well as a long coronoid process result in a lower jaw that is reconstructed as relatively much more stressed in triceratopsins. © 2015 Anatomical Society.

Guided Search for Triple Conjunctions

PubMed Central

Nordfang, Maria; Wolfe, Jeremy M

2017-01-01

A key tenet of Feature Integration Theory and related theories such as Guided Search (GS) is that the binding of basic features requires attention. This would seem to predict that conjunctions of features of objects that have not been attended should not influence search. However, Found (1998) reported that an irrelevant feature (size) improved the efficiency of search for a color × orientation conjunction if it was correlated with the other two features across the display compared to the case where size was not correlated with color and orientation features. We examine this issue with somewhat different stimuli. We use triple conjunctions of color, orientation and shape (e.g. search for a red, vertical, oval-shaped item). This allows us to manipulate the number of features that each distractor shares with the target (Sharing) and it allows us to vary the total number of distractor types (and, thus, the number of groups of identical items; Grouping). We find these triple conjunction searches are generally very efficient – producing very shallow reaction time (RT) × set size slopes, consistent with strong guidance by basic features. Nevertheless, both of these variables, Sharing and Grouping modulate performance. These influences are not predicted by previous accounts of GS. However, both can be accommodated in a GS framework. Alternatively, it is possible, if not necessary, to see these effects as evidence for “preattentive binding” of conjunctions. PMID:25005070

Guided search for triple conjunctions.

PubMed

Nordfang, Maria; Wolfe, Jeremy M

2014-08-01

A key tenet of feature integration theory and of related theories such as guided search (GS) is that the binding of basic features requires attention. This would seem to predict that conjunctions of features of objects that have not been attended should not influence search. However, Found (1998) reported that an irrelevant feature (size) improved the efficiency of search for a Color × Orientation conjunction if it was correlated with the other two features across the display, as compared to the case in which size was not correlated with color and orientation features. We examined this issue with somewhat different stimuli. We used triple conjunctions of color, orientation, and shape (e.g., search for a red, vertical, oval-shaped item). This allowed us to manipulate the number of features that each distractor shared with the target (sharing) and it allowed us to vary the total number of distractor types (and, thus, the number of groups of identical items: grouping). We found that these triple conjunction searches were generally very efficient--producing very shallow Reaction Time × Set Size slopes, consistent with strong guidance by basic features. Nevertheless, both of the variables, sharing and grouping, modulated performance. These influences were not predicted by previous accounts of GS; however, both can be accommodated in a GS framework. Alternatively, it is possible, though not necessary, to see these effects as evidence for "preattentive binding" of conjunctions.

Polymeric nanoparticles containing diazepam: preparation, optimization, characterization, in-vitro drug release and release kinetic study

NASA Astrophysics Data System (ADS)

Bohrey, Sarvesh; Chourasiya, Vibha; Pandey, Archna

2016-03-01

Nanoparticles formulated from biodegradable polymers like poly(lactic-co-glycolic acid) (PLGA) are being extensively investigated as drug delivery systems due to their two important properties such as biocompatibility and controlled drug release characteristics. The aim of this work to formulated diazepam loaded PLGA nanoparticles by using emulsion solvent evaporation technique. Polyvinyl alcohol (PVA) is used as stabilizing agent. Diazepam is a benzodiazepine derivative drug, and widely used as an anticonvulsant in the treatment of various types of epilepsy, insomnia and anxiety. This work investigates the effects of some preparation variables on the size and shape of nanoparticles prepared by emulsion solvent evaporation method. These nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM). Zeta potential study was also performed to understand the surface charge of nanoparticles. The drug release from drug loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by various kinetic models. The results show that sonication time, polymer content, surfactant concentration, ratio of organic to aqueous phase volume, and the amount of drug have an important effect on the size of nanoparticles. Hopefully we produced spherical shape Diazepam loaded PLGA nanoparticles with a size range under 250 nm with zeta potential -23.3 mV. The in vitro drug release analysis shows sustained release of drug from nanoparticles and follow Korsmeyer-Peppas model.

ICP-MS Analysis of Lanthanide-Doped Nanoparticles as a Non-Radiative, Multiplex Approach to Quantify Biodistribution and Blood Clearance

PubMed Central

Crayton, Samuel H.; Elias, Andrew; Al-Zaki, Ajlan; Cheng, Zhiliang; Tsourkas, Andrew

2011-01-01

Recent advances in material science and chemistry have led to the development of nanoparticles with diverse physicochemical properties, e.g. size, charge, shape, and surface chemistry. Evaluating which physicochemical properties are best for imaging and therapeutic studies is challenging not only because of the multitude of samples to evaluate, but also because of the large experimental variability associated with in vivo studies (e.g. differences in tumor size, injected dose, subject weight, etc.). To address this issue, we have developed a lanthanide-doped nanoparticle system and analytical method that allows for the quantitative comparison of multiple nanoparticle compositions simultaneously. Specifically, superparamagnetic iron oxide (SPIO) with a range of different sizes and charges were synthesized, each with a unique lanthanide dopant. Following the simultaneous injection of the various SPIO compositions into tumor-bearing mice, inductively coupled plasma mass spectroscopy (ICP-MS) was used to quantitatively and orthogonally assess the concentration of each SPIO composition in serial blood samples and the resected tumor and organs. The method proved generalizable to other nanoparticle platforms, including dendrimers, liposomes, and polymersomes. This approach provides a simple, cost-effective, and non-radiative method to quantitatively compare tumor localization, biodistribution, and blood clearance of more than 10 nanoparticle compositions simultaneously, removing subject-to-subject variability. PMID:22100983

Absorption Efficiencies of Forsterite. I: DDA Explorations in Grain Shape and Size

NASA Technical Reports Server (NTRS)

Lindsay, Sean S.; Wooden, Diane; Harker, David E.; Kelley, Michael S.; Woodward, Charles E.; Murphy, Jim R.

2013-01-01

We compute the absorption efficiency (Q(sub abs)) of forsterite using the discrete dipole approximation (DDA) in order to identify and describe what characteristics of crystal grain shape and size are important to the shape, peak location, and relative strength of spectral features in the 8 - 40 micron wavelength range. Using the DDSCAT code, we compute Q(sub abs) for non-spherical polyhedral grain shapes with a(sub eff) = 0.1 micron. The shape characteristics identified are: 1) elongation/reduction along one of three crystallographic axes; 2) asymmetry, such that all three crystallographic axes are of different lengths; and 3) the presence of crystalline faces that are not parallel to a specific crystallographic axis, e.g., non-rectangular prisms and (di)pyramids. Elongation/reduction dominates the locations and shapes of spectral features near 10, 11, 16, 23.5, 27, and 33.5 micron, while asymmetry and tips are secondary shape effects. Increasing grain sizes (0.1 - 1.0 micron) shifts the 10, 11 micron features systematically towards longer wavelengths and relative to the 11 micron feature increases the strengths and slightly broadens the longer wavelength features. Seven spectral shape classes are established for crystallographic a-, b-, and c-axes and include columnar and platelet shapes plus non-elongated or equant grain shapes. The spectral shape classes and the effects of grain size have practical application in identifying or excluding columnar, platelet or equant forsterite grain shapes in astrophysical environs. Identification of the shape characteristics of forsterite from 8 - 40 micron spectra provides a potential means to probe the temperatures at which forsterite formed.

[Eyeball shape in children with emmetropia and myopia].

PubMed

Dolzhich, G I; Shurygina, I P; Shapovalova, V M

1991-01-01

In order to determine the eyeball shape, the authors have carried out ultrasonic biometry of its three major parameters, the anteroposterior axis (APA), horizontal diameter (HD), and vertical diameter (VD), and estimated the ratios of these values (APA/HD and APA/VD) in children with emmetropia (234 eyes) and those with slight and medium-grave myopia (660 eyes), aged 7 to 14. The findings evidence a compressed ellipsoidal shape of the eyeball, presenting as a vertical oval, in all subjects with emmetropic refraction, whatever their age. In myopia the eyeball shape transforms, and all the eyeball sizes are increased, but the APA size is growing more rapidly than the rest sizes, and the eyeball acquires the ball shape with a trend to an elongated ellipsoidal shape. The mean APA length in 7-14-year-old children with emmetropia was up to 23 +/- 0.15 mm, whereas in those with the ball shape of the eyeball it was distended.

Engineering cartilage substitute with a specific size and shape using porous high-density polyethylene (HDPE) as internal support.

PubMed

Wu, Yujia; Zhu, Lie; Jiang, Hua; Liu, Wei; Liu, Yu; Cao, Yilin; Zhou, Guangdong

2010-04-01

Despite the great advances in cartilage engineering, constructing cartilage of large sizes and appropriate shapes remains a great challenge, owing to limits in thickness of regenerated cartilage and to inferior mechanical properties of scaffolds. This study introduces a pre-shaped polyglycolic acid (PGA)-coated porous high-density polyethylene (HDPE) scaffold to overcome these challenges. HDPE was carved into cylindrical rods and wrapped around by PGA fibres to form PGA-HDPE scaffolds. Porcine chondrocytes were seeded into the scaffolds and the constructs were cultured in vitro for 2 weeks before subcutaneous implantation into nude mice. Scaffolds made purely of PGA with the same size and shape were used as a control. After 8 weeks of implantation, the construct formed cartilage-like tissue and retained its pre-designed shape and size. In addition, the regenerated cartilage grew and completely surrounded the HDPE core, which made the entire cartilage substitute biocompatible to its implanted environment as native cartilage similarly does. By contrast, the shape and size of the constructs in the control group seriously deformed and obvious hollow cavity and necrotic tissue were observed in the inner region. These results demonstrate that the use of HDPE as the internal support of a biodegradable scaffold has the potential to circumvent the problems of limitations in size and shape, with promising implications for the development of engineered cartilage appropriate for clinical applications. Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Preparation of α-alumina nanoparticles with various shapes via hydrothermal phase transformation under supercritical water conditions

NASA Astrophysics Data System (ADS)

Hakuta, Y.; Nagai, N.; Suzuki, Y.-H.; Kodaira, T.; Bando, K. K.; Takashima, H.; Mizukami, F.

2013-12-01

Alumina (Al2O3) fine particles are widely used as industrial materials including fillers for metal or plastics, paints, polisher, cosmetics and electric substrates, due to its high hardness, chemical stability, and high thermal conductivity. The performance of those industrial products is closely related to the particle size or shape of the alumina particles used, and thus a new synthetic method to control size, shape, and crystal structure of the aluminum oxide is desired for the improvement of the performance. Hydrothermal phase transformation using various aluminum compounds such as oxide, hydroxide, and salt as a staring material, is known as one of the synthetic methods for producing alumina fine particles; however, the influence about the size and shape of the starting aluminum compounds has been little mentioned, although they strongly affect the size and shape of the final products. In this study, we investigated the influence of the shape, size and crystal structure of the starting aluminum compounds on those of the products, and newly succeeded in the production of rod-like α-Al2O3 nanoparticles from fibrous boehmite nanoparticles using hydrothermal phase transformation under supercritical water conditions.

Fabrication of ordered arrays of micro- and nanoscale features with control over their shape and size via templated solid-state dewetting.

PubMed

Ye, Jongpil

2015-05-08

Templated solid-state dewetting of single-crystal films has been shown to be used to produce regular patterns of various shapes. However, the materials for which this patterning method is applicable, and the size range of the patterns produced are still limited. Here, it is shown that ordered arrays of micro- and nanoscale features can be produced with control over their shape and size via solid-state dewetting of patches patterned from single-crystal palladium and nickel films of different thicknesses and orientations. The shape and size characteristics of the patterns are found to be widely controllable with varying the shape, width, thickness, and orientation of the initial patches. The morphological evolution of the patches is also dependent on the film material, with different dewetting behaviors observed in palladium and nickel films. The mechanisms underlying the pattern formation are explained in terms of the influence on Rayleigh-like instability of the patch geometry and the surface energy anisotropy of the film material. This mechanistic understanding of pattern formation can be used to design patches for the precise fabrication of micro- and nanoscale structures with the desired shapes and feature sizes.

Fabrication of ordered arrays of micro- and nanoscale features with control over their shape and size via templated solid-state dewetting

PubMed Central

Ye, Jongpil

2015-01-01

Templated solid-state dewetting of single-crystal films has been shown to be used to produce regular patterns of various shapes. However, the materials for which this patterning method is applicable, and the size range of the patterns produced are still limited. Here, it is shown that ordered arrays of micro- and nanoscale features can be produced with control over their shape and size via solid-state dewetting of patches patterned from single-crystal palladium and nickel films of different thicknesses and orientations. The shape and size characteristics of the patterns are found to be widely controllable with varying the shape, width, thickness, and orientation of the initial patches. The morphological evolution of the patches is also dependent on the film material, with different dewetting behaviors observed in palladium and nickel films. The mechanisms underlying the pattern formation are explained in terms of the influence on Rayleigh-like instability of the patch geometry and the surface energy anisotropy of the film material. This mechanistic understanding of pattern formation can be used to design patches for the precise fabrication of micro- and nanoscale structures with the desired shapes and feature sizes. PMID:25951816

A new approach to children's footwear based on foot type classification.

PubMed

Mauch, M; Grau, S; Krauss, I; Maiwald, C; Horstmann, T

2009-08-01

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.

Gland segmentation in prostate histopathological images

PubMed Central

Singh, Malay; Kalaw, Emarene Mationg; Giron, Danilo Medina; Chong, Kian-Tai; Tan, Chew Lim; Lee, Hwee Kuan

2017-01-01

Abstract. Glandular structural features are important for the tumor pathologist in the assessment of cancer malignancy of prostate tissue slides. The varying shapes and sizes of glands combined with the tedious manual observation task can result in inaccurate assessment. There are also discrepancies and low-level agreement among pathologists, especially in cases of Gleason pattern 3 and pattern 4 prostate adenocarcinoma. An automated gland segmentation system can highlight various glandular shapes and structures for further analysis by the pathologist. These objective highlighted patterns can help reduce the assessment variability. We propose an automated gland segmentation system. Forty-three hematoxylin and eosin-stained images were acquired from prostate cancer tissue slides and were manually annotated for gland, lumen, periacinar retraction clefting, and stroma regions. Our automated gland segmentation system was trained using these manual annotations. It identifies these regions using a combination of pixel and object-level classifiers by incorporating local and spatial information for consolidating pixel-level classification results into object-level segmentation. Experimental results show that our method outperforms various texture and gland structure-based gland segmentation algorithms in the literature. Our method has good performance and can be a promising tool to help decrease interobserver variability among pathologists. PMID:28653016

AMCC casting development. Volume 1: Executive Summary

NASA Technical Reports Server (NTRS)

1995-01-01

The Advanced Combustion Chamber Casting (AMCC) has been a technically challenging part due to its size, configuration, and alloy type. The height and weight of the wax pattern assembly necessitated the development of a hollow gating system to ensure structural integrity of the shell throughout the investment process. The complexity in the jacket area of the casting required the development of an innovative casting technology that PCC has termed 'TGC' or Thermal Gradient Control. This method, of setting up thermal gradients in the casting during solidification, represents a significant process improvement for PCC and has been successfully implemented on other programs. Metallurgical integrity of the final four castings was very good. Only the areas of the parts that utilized 'TGC Shape & Location System #2' showed any significant areas of microshrinkage when evaluated by non-destructive tests. Alumina oxides detected by FPI on the 'float' surfaces (top sid surfaces of the casting during solidification) of the part were almost entirely less than the acceptance criteria of .032 inches in diameter. Destructive chem mill of the castings was required to determine the effect of the process variables used during the processing of these last four parts (with the exception of the 'Shape & Location of TGC' variable).

Modelling and optimization of semi-solid processing of 7075 Al alloy

NASA Astrophysics Data System (ADS)

Binesh, B.; Aghaie-Khafri, M.

2017-09-01

The new modified strain-induced melt activation (SIMA) process presented by Binesh and Aghaie-Khafri was optimized using a response surface methodology to improve the thixotropic characteristics of semi-solid 7075 alloy. The responses, namely the average grain size and the shape factor, were considered as functions of three independent input variables: effective strain, isothermal holding temperature and time. Mathematical models for the responses were developed using the regression analysis technique, and the adequacy of the models was validated by the analysis of variance method. The calculated results correlated fairly well with the experiments. It was found that all the first- and second-order terms of the independent parameters and the interactive terms of the effective strain and holding time were statistically significant for the responses. In order to simultaneously optimize the responses, the desirable values for the effective strain, holding temperature and time were predicted to be 5.1, 609 °C and 14 min, respectively, when employing the desirability function approach. Based on the optimization results, a significant improvement in the average grain size and shape factor of the semi-solid slurry prepared by the new modified SIMA process was observed.

A PDE approach for quantifying and visualizing tumor progression and regression

NASA Astrophysics Data System (ADS)

Sintay, Benjamin J.; Bourland, J. Daniel

2009-02-01

Quantification of changes in tumor shape and size allows physicians the ability to determine the effectiveness of various treatment options, adapt treatment, predict outcome, and map potential problem sites. Conventional methods are often based on metrics such as volume, diameter, or maximum cross sectional area. This work seeks to improve the visualization and analysis of tumor changes by simultaneously analyzing changes in the entire tumor volume. This method utilizes an elliptic partial differential equation (PDE) to provide a roadmap of boundary displacement that does not suffer from the discontinuities associated with other measures such as Euclidean distance. Streamline pathways defined by Laplace's equation (a commonly used PDE) are used to track tumor progression and regression at the tumor boundary. Laplace's equation is particularly useful because it provides a smooth, continuous solution that can be evaluated with sub-pixel precision on variable grid sizes. Several metrics are demonstrated including maximum, average, and total regression and progression. This method provides many advantages over conventional means of quantifying change in tumor shape because it is observer independent, stable for highly unusual geometries, and provides an analysis of the entire three-dimensional tumor volume.

The effects of colorimetric detection of heavy metal ions based on Au nanoparticles (NPs): size and shape—a case of Co2+

NASA Astrophysics Data System (ADS)

Leng, Yumin; He, Junbao; Li, Bo; Xing, Xiaojing; Guo, Yongming; Ye, Liqun; Lu, Zhiwen

2017-09-01

The different sized and shaped Au NPs have intrigued considerable attention, because they possess different surface plasma resonance (SPR) absorption bands and thus result in many colorimetric Au NP-based detection applications. In this article, four different sized and shaped Au NPs of nanodots/rods were prepared and characterized. The as-prepared Au NPs were modified by the negatively charged anions of [SCH2CO2]2- to investigate both the size and shape effects of modified Au NPs on colorimetric detection of Co2+ and the corresponding SPR absorption properties. The different-shaped Au NPs possess different SPR absorption properties. The Au nanorods appeared to be colorimetric sensitive for Co2+ sensing.

Body size and allometric shape variation in the molly Poecilia vivipara along a gradient of salinity and predation.

PubMed

Araújo, Márcio S; Perez, S Ivan; Magazoni, Maria Julia C; Petry, Ana C

2014-12-04

Phenotypic diversity among populations may result from divergent natural selection acting directly on traits or via correlated responses to changes in other traits. One of the most frequent patterns of correlated response is the proportional change in the dimensions of anatomical traits associated with changes in growth or absolute size, known as allometry. Livebearing fishes subject to predation gradients have been shown to repeatedly evolve larger caudal peduncles and smaller cranial regions under high predation regimes. Poecilia vivipara is a livebearing fish commonly found in coastal lagoons in the north of the state of Rio de Janeiro, Brazil. Similar to what is observed in other predation gradients, lagoons inhabited by P. vivipara vary in the presence of piscivorous fishes; contrary to other poeciliid systems, populations of P. vivipara vary greatly in body size, which opens the possibility of strong allometric effects on shape variation. Here we investigated body shape diversification among six populations of P. vivipara along a predation gradient and its relationship with allometric trajectories within and among populations. We found substantial body size variation and correlated shape changes among populations. Multivariate regression analysis showed that size variation among populations accounted for 66% of shape variation in females and 38% in males, suggesting that size is the most important dimension underlying shape variation among populations of P. vivipara in this system. Changes in the relative sizes of the caudal peduncle and cranial regions were only partly in line with predictions from divergent natural selection associated with predation regime. Our results suggest the possibility that adaptive shape variation among populations has been partly constrained by allometry in P. vivipara. Processes governing body size changes are therefore important in the diversification of this species. We conclude that in species characterized by substantial among-population differences in body size, ignoring allometric effects when investigating divergent natural selection's role in phenotypic diversification might not be warranted.

Fish movement and habitat use depends on water body size and shape

USGS Publications Warehouse

Woolnough, D.A.; Downing, J.A.; Newton, T.J.

2009-01-01

Home ranges are central to understanding habitat diversity, effects of fragmentation and conservation. The distance that an organism moves yields information on life history, genetics and interactions with other organisms. Present theory suggests that home range is set by body size of individuals. Here, we analyse estimates of home ranges in lakes and rivers to show that body size of fish and water body size and shape influence home range size. Using 71 studies including 66 fish species on five continents, we show that home range estimates increased with increasing water body size across water body shapes. This contrasts with past studies concluding that body size sets home range. We show that water body size was a consistently significant predictor of home range. In conjunction, body size and water body size can provide improved estimates of home range than just body size alone. As habitat patches are decreasing in size worldwide, our findings have implications for ecology, conservation and genetics of populations in fragmented ecosystems. ?? 2008 Blackwell Munksgaard.

How to Build a Bacterial Cell: MreB as the Foreman of E. coli Construction.

PubMed

Shi, Handuo; Bratton, Benjamin P; Gitai, Zemer; Huang, Kerwyn Casey

2018-03-08

Cell shape matters across the kingdoms of life, and cells have the remarkable capacity to define and maintain specific shapes and sizes. But how are the shapes of micron-sized cells determined from the coordinated activities of nanometer-sized proteins? Here, we review general principles that have surfaced through the study of rod-shaped bacterial growth. Imaging approaches have revealed that polymers of the actin homolog MreB play a central role. MreB both senses and changes cell shape, thereby generating a self-organizing feedback system for shape maintenance. At the molecular level, structural and computational studies indicate that MreB filaments exhibit tunable mechanical properties that explain their preference for certain geometries and orientations along the cylindrical cell body. We illustrate the regulatory landscape of rod-shape formation and the connectivity between cell shape, cell growth, and other aspects of cell physiology. These discoveries provide a framework for future investigations into the architecture and construction of microbes. Copyright © 2018 Elsevier Inc. All rights reserved.

Costs of storing colour and complex shape in visual working memory: Insights from pupil size and slow waves.

PubMed

Kursawe, Michael A; Zimmer, Hubert D

2015-06-01

We investigated the impact of perceptual processing demands on visual working memory of coloured complex random polygons during change detection. Processing load was assessed by pupil size (Exp. 1) and additionally slow wave potentials (Exp. 2). Task difficulty was manipulated by presenting different set sizes (1, 2, 4 items) and by making different features (colour, shape, or both) task-relevant. Memory performance in the colour condition was better than in the shape and both condition which did not differ. Pupil dilation and the posterior N1 increased with set size independent of type of feature. In contrast, slow waves and a posterior P2 component showed set size effects but only if shape was task-relevant. In the colour condition slow waves did not vary with set size. We suggest that pupil size and N1 indicates different states of attentional effort corresponding to the number of presented items. In contrast, slow waves reflect processes related to encoding and maintenance strategies. The observation that their potentials vary with the type of feature (simple colour versus complex shape) indicates that perceptual complexity already influences encoding and storage and not only comparison of targets with memory entries at the moment of testing. Copyright © 2015 Elsevier B.V. All rights reserved.

Ontogenetic shifts in morphology and resource use of cisco Coregonus artedi.

PubMed

Muir, A M; Vecsei, P; Pratt, T C; Krueger, C C; Power, M; Reist, J D

2013-02-01

Two previously described lacustrine cisco Coregonus spp. morphs [i.e. a small (<300 mm fork length, L(F)), low-gillraker (≤44) morph and a large (≥300 mm L(F) ), high-gillraker (≥45) morph] from Great Slave Lake, NT, Canada, were found to be synonymous with cisco Coregonus artedi. Geometric body shape did not differ between the two size classes nor could they be differentiated by 24 size-corrected linear measurements, indicating that the two groups had similar phenotypes. Strong, positive correlations between all linear characters and geometric centroid size (a composite variable of fish body length, mass and age) suggested that body morphology changed with age as fish grew. Total gillraker number (N(GR)) increased with L(F) according to: N(GR) = 36.3 + 0.034L(F). Differences in gillraker number and phenotype with age and size were explained by shifts in habitat and trophic resource use. Relative abundance within 0-30, 30-60, 60-90 and >90 m depth strata differed between size classes suggesting that morphology changed when fish shifted their habitat as they grew older. Large C. artedi had lower δ(13)C and slightly higher δ(15)N, indicating greater reliance on pelagic prey resources (i.e. more or larger zooplankton, such as Mysis spp.), compared to small C. artedi, which relied slightly more on benthic prey. Gillraker shape and number have always been used as key diagnostic characters in coregonine taxonomy; based on the findings presented here, ontogenetic shifts should be accounted for in resulting classifications. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

Ex vivo magnetic resonance imaging of crystalline lens dimensions in chicken.

PubMed

Tattersall, Rebecca J; Prashar, Ankush; Singh, Krish D; Tokarczuk, Pawel F; Erichsen, Jonathan T; Hocking, Paul M; Guggenheim, Jeremy A

2010-02-02

A reduction in the power of the crystalline lens during childhood is thought to be important in the emmetropization of the maturing eye. However, in humans and model organisms, little is known about the factors that determine the dimensions of the crystalline lens and in particular whether these different parameters (axial thickness, surface curvatures, equatorial diameter, and volume) are under a common source of control or regulated independently of other aspects of eye size and shape. Using chickens from a broiler-layer experimental cross as a model system, three-dimensional magnetic resonance imaging (MRI) scans were obtained at 115-microm isotropic resolution for one eye of 501 individuals aged 3-weeks old. After fixation with paraformaldehyde, the excised eyes were scanned overnight (16 h) in groups of 16 arranged in a 2x2x4 array. Lens dimensions were calculated from each image by fitting a three-dimensional mesh model to the lens, using the semi-automated analysis program mri3dX. The lens dimensions were compared to measures of eye and body size obtained in vivo using techniques that included keratometry and A-scan ultrasonography. A striking finding was that axial lens thickness measured using ex vivo MRI was only weakly correlated with lens thickness measured in vivo by ultrasonography (r=0.19, p<0.001). In addition, the MRI lens thickness estimates had a lower mean value and much higher variance. Indeed, about one-third of crystalline lenses showed a kidney-shaped appearance instead of the typical biconvex shape. Since repeat MRI scans of the same eye showed a high degree of reproducibility for the scanning and mri3dX analysis steps (the correlation in repeat lens thickness measurements was r=0.95, p<0.001) and a recent report has shown that paraformaldehyde fixation induces a loss of water from the human crystalline lens, it is likely that the tissue fixation step caused a variable degree of shrinkage and a change in shape to the lenses examined here. Despite this serious source of imprecision, we found significant correlations between lens volume and eye/body size (p<0.001) and between lens equatorial diameter and eye/body size (p<0.001) in these chickens. Our results suggest that certain aspects of lens size (specifically, lens volume and equatorial diameter) are controlled by factors that also regulate the size of the eye and body (presumably, predominantly genetic factors). However, since it has been shown previously that axial lens thickness is regulated almost independently of eye and body size, these results suggest that different systems might operate to control lens volume/diameter and lens thickness in normal chickens.

Ex vivo magnetic resonance imaging of crystalline lens dimensions in chicken

PubMed Central

Tattersall, Rebecca J.; Prashar, Ankush; Singh, Krish D.; Tokarczuk, Pawel F.; Erichsen, Jonathan T.; Hocking, Paul M.

2010-01-01

Purpose A reduction in the power of the crystalline lens during childhood is thought to be important in the emmetropization of the maturing eye. However, in humans and model organisms, little is known about the factors that determine the dimensions of the crystalline lens and in particular whether these different parameters (axial thickness, surface curvatures, equatorial diameter, and volume) are under a common source of control or regulated independently of other aspects of eye size and shape. Methods Using chickens from a broiler-layer experimental cross as a model system, three-dimensional magnetic resonance imaging (MRI) scans were obtained at 115-µm isotropic resolution for one eye of 501 individuals aged 3-weeks old. After fixation with paraformaldehyde, the excised eyes were scanned overnight (16 h) in groups of 16 arranged in a 2×2×4 array. Lens dimensions were calculated from each image by fitting a three-dimensional mesh model to the lens, using the semi-automated analysis program mri3dX. The lens dimensions were compared to measures of eye and body size obtained in vivo using techniques that included keratometry and A-scan ultrasonography. Results A striking finding was that axial lens thickness measured using ex vivo MRI was only weakly correlated with lens thickness measured in vivo by ultrasonography (r=0.19, p<0.001). In addition, the MRI lens thickness estimates had a lower mean value and much higher variance. Indeed, about one-third of crystalline lenses showed a kidney-shaped appearance instead of the typical biconvex shape. Since repeat MRI scans of the same eye showed a high degree of reproducibility for the scanning and mri3dX analysis steps (the correlation in repeat lens thickness measurements was r=0.95, p<0.001) and a recent report has shown that paraformaldehyde fixation induces a loss of water from the human crystalline lens, it is likely that the tissue fixation step caused a variable degree of shrinkage and a change in shape to the lenses examined here. Despite this serious source of imprecision, we found significant correlations between lens volume and eye/body size (p<0.001) and between lens equatorial diameter and eye/body size (p<0.001) in these chickens. Conclusions Our results suggest that certain aspects of lens size (specifically, lens volume and equatorial diameter) are controlled by factors that also regulate the size of the eye and body (presumably, predominantly genetic factors). However, since it has been shown previously that axial lens thickness is regulated almost independently of eye and body size, these results suggest that different systems might operate to control lens volume/diameter and lens thickness in normal chickens. PMID:20142845

Sensitivity analysis for axis rotation diagrid structural systems according to brace angle changes

NASA Astrophysics Data System (ADS)

Yang, Jae-Kwang; Li, Long-Yang; Park, Sung-Soo

2017-10-01

General regular shaped diagrid structures can express diverse shapes because braces are installed along the exterior faces of the structures and the structures have no columns. However, since irregular shaped structures have diverse variables, studies to assess behaviors resulting from various variables are continuously required to supplement the imperfections related to such variables. In the present study, materials elastic modulus and yield strength were selected as variables for strength that would be applied to diagrid structural systems in the form of Twisters among the irregular shaped buildings classified by Vollers and that affect the structural design of these structural systems. The purpose of this study is to conduct sensitivity analysis for axial rotation diagrid structural systems according to changes in brace angles in order to identify the design variables that have relatively larger effects and the tendencies of the sensitivity of the structures according to changes in brace angles and axial rotation angles.

Body shape and size depictions of African American women in JET magazine, 1953-2006.

PubMed

Dawson-Andoh, Nana A; Gray, James J; Soto, José A; Parker, Scott

2011-01-01

Depictions of Caucasian women in the mainstream media have become increasingly thinner in size and straighter in shape. These changes may be inconsistent with the growing influence of African American beauty ideals, which research has established as more accepting of larger body sizes and more curvaceous body types than Caucasians. The present study looked at trends in the portrayal of African American women featured in JET magazine from 1953 to 2006. Beauty of the Week (BOW) images were collected and analyzed to examine body size (estimated by independent judges) and body shape (estimated by waist-to-hip ratio). We expected body sizes to increase and body shapes to become more curvaceous. Results revealed a rise in models' body size consistent with expectations, but an increase in waist-to-hip ratio, contrary to prediction. Our findings suggest that the African American feminine beauty ideal reflects both consistencies with and departures from mainstream cultural ideals. Copyright © 2010 Elsevier Ltd. All rights reserved.

Dissection of Genetic Factors underlying Wheat Kernel Shape and Size in an Elite × Nonadapted Cross using a High Density SNP Linkage Map.

PubMed

Kumar, Ajay; Mantovani, E E; Seetan, R; Soltani, A; Echeverry-Solarte, M; Jain, S; Simsek, S; Doehlert, D; Alamri, M S; Elias, E M; Kianian, S F; Mergoum, M

2016-03-01

Wheat kernel shape and size has been under selection since early domestication. Kernel morphology is a major consideration in wheat breeding, as it impacts grain yield and quality. A population of 160 recombinant inbred lines (RIL), developed using an elite (ND 705) and a nonadapted genotype (PI 414566), was extensively phenotyped in replicated field trials and genotyped using Infinium iSelect 90K assay to gain insight into the genetic architecture of kernel shape and size. A high density genetic map consisting of 10,172 single nucleotide polymorphism (SNP) markers, with an average marker density of 0.39 cM/marker, identified a total of 29 genomic regions associated with six grain shape and size traits; ∼80% of these regions were associated with multiple traits. The analyses showed that kernel length (KL) and width (KW) are genetically independent, while a large number (∼59%) of the quantitative trait loci (QTL) for kernel shape traits were in common with genomic regions associated with kernel size traits. The most significant QTL was identified on chromosome 4B, and could be an ortholog of major rice grain size and shape gene or . Major and stable loci also were identified on the homeologous regions of Group 5 chromosomes, and in the regions of (6A) and (7A) genes. Both parental genotypes contributed equivalent positive QTL alleles, suggesting that the nonadapted germplasm has a great potential for enhancing the gene pool for grain shape and size. This study provides new knowledge on the genetic dissection of kernel morphology, with a much higher resolution, which may aid further improvement in wheat yield and quality using genomic tools. Copyright © 2016 Crop Science Society of America.

Influence of Nanopore Shapes on Thermal Conductivity of Two-Dimensional Nanoporous Material.

PubMed

Huang, Cong-Liang; Huang, Zun; Lin, Zi-Zhen; Feng, Yan-Hui; Zhang, Xin-Xin; Wang, Ge

2016-12-01

The influence of nanopore shapes on the electronic thermal conductivity (ETC) was studied in this paper. It turns out that with same porosity, the ETC will be quite different for different nanopore shapes, caused by the different channel width for different nanopore shapes. With same channel width, the influence of different nanopore shapes can be approximately omitted if the nanopore is small enough (smaller than 0.5 times EMFP in this paper). The ETC anisotropy was discovered for triangle nanopores at a large porosity with a large nanopore size, while there is a similar ETC for small pore size. It confirmed that the structure difference for small pore size may not be seen by electrons in their moving.

Shape recognition of microbial cells by colloidal cell imprints

NASA Astrophysics Data System (ADS)

Borovička, Josef; Stoyanov, Simeon D.; Paunov, Vesselin N.

2013-08-01

We have engineered a class of colloids which can recognize the shape and size of targeted microbial cells and selectively bind to their surfaces. These imprinted colloid particles, which we called ``colloid antibodies'', were fabricated by partial fragmentation of silica shells obtained by templating the targeted microbial cells. We successfully demonstrated the shape and size recognition between such colloidal imprints and matching microbial cells. High percentage of binding events of colloidal imprints with the size matching target particles was achieved. We demonstrated selective binding of colloidal imprints to target microbial cells in a binary mixture of cells of different shapes and sizes, which also resulted in high binding selectivity. We explored the role of the electrostatic interactions between the target cells and their colloid imprints by pre-coating both of them with polyelectrolytes. Selective binding occurred predominantly in the case of opposite surface charges of the colloid cell imprint and the targeted cells. The mechanism of the recognition is based on the amplification of the surface adhesion in the case of shape and size match due to the increased contact area between the target cell and the colloidal imprint. We also tested the selective binding for colloid imprints of particles of fixed shape and varying sizes. The concept of cell recognition by colloid imprints could be used for development of colloid antibodies for shape-selective binding of microbes. Such colloid antibodies could be additionally functionalized with surface groups to enhance their binding efficiency to cells of specific shape and deliver a drug payload directly to their surface or allow them to be manipulated using external fields. They could benefit the pharmaceutical industry in developing selective antimicrobial therapies and formulations.

Visualization of the variability of 3D statistical shape models by animation.

PubMed

Lamecker, Hans; Seebass, Martin; Lange, Thomas; Hege, Hans-Christian; Deuflhard, Peter

2004-01-01

Models of the 3D shape of anatomical objects and the knowledge about their statistical variability are of great benefit in many computer assisted medical applications like images analysis, therapy or surgery planning. Statistical model of shapes have successfully been applied to automate the task of image segmentation. The generation of 3D statistical shape models requires the identification of corresponding points on two shapes. This remains a difficult problem, especially for shapes of complicated topology. In order to interpret and validate variations encoded in a statistical shape model, visual inspection is of great importance. This work describes the generation and interpretation of statistical shape models of the liver and the pelvic bone.

General shape optimization capability

NASA Technical Reports Server (NTRS)

Chargin, Mladen K.; Raasch, Ingo; Bruns, Rudolf; Deuermeyer, Dawson

1991-01-01

A method is described for calculating shape sensitivities, within MSC/NASTRAN, in a simple manner without resort to external programs. The method uses natural design variables to define the shape changes in a given structure. Once the shape sensitivities are obtained, the shape optimization process is carried out in a manner similar to property optimization processes. The capability of this method is illustrated by two examples: the shape optimization of a cantilever beam with holes, loaded by a point load at the free end (with the shape of the holes and the thickness of the beam selected as the design variables), and the shape optimization of a connecting rod subjected to several different loading and boundary conditions.

The Effect of Defects on the Fatigue Initiation Process in Two P/M Superalloys.

DTIC Science & Technology

1980-09-01

determine the effect of Sdfect size, shape, and population on the fatigue initiation process in two high strength P/M superalloys, AF-l5 and AF2-lDA. The...to systematically determine the effects of defect size, shape, and population on fatigue. It is true that certain trends have been established...to determine the relative effects of defect size, shape, and population on the crack initiation life of a representative engineering material

Microstructure as a function of the grain size distribution for packings of frictionless disks: Effects of the size span and the shape of the distribution.

PubMed

Estrada, Nicolas; Oquendo, W F

2017-10-01

This article presents a numerical study of the effects of grain size distribution (GSD) on the microstructure of two-dimensional packings of frictionless disks. The GSD is described by a power law with two parameters controlling the size span and the shape of the distribution. First, several samples are built for each combination of these parameters. Then, by means of contact dynamics simulations, the samples are densified in oedometric conditions and sheared in a simple shear configuration. The microstructure is analyzed in terms of packing fraction, local ordering, connectivity, and force transmission properties. It is shown that the microstructure is notoriously affected by both the size span and the shape of the GSD. These findings confirm recent observations regarding the size span of the GSD and extend previous works by describing the effects of the GSD shape. Specifically, we find that if the GSD shape is varied by increasing the proportion of small grains by a certain amount, it is possible to increase the packing fraction, increase coordination, and decrease the proportion of floating particles. Thus, by carefully controlling the GSD shape, it is possible to obtain systems that are denser and better connected, probably increasing the system's robustness and optimizing important strength properties such as stiffness, cohesion, and fragmentation susceptibility.

Multi-shaped beam: development status and update on lithography results

NASA Astrophysics Data System (ADS)

Slodowski, Matthias; Doering, Hans-Joachim; Dorl, Wolfgang; Stolberg, Ines A.

2011-04-01

According to the ITRS [1] photo mask is a significant challenge for the 22nm technology node requirements and beyond. Mask making capability and cost escalation continue to be critical for future lithography progress. On the technological side mask specifications and complexity have increased more quickly than the half-pitch requirements on the wafer designated by the roadmap due to advanced optical proximity correction and double patterning demands. From the economical perspective mask costs have significantly increased each generation, in which mask writing represents a major portion. The availability of a multi-electron-beam lithography system for mask write application is considered a potential solution to overcome these challenges [2, 3]. In this paper an update of the development status of a full-package high-throughput multi electron-beam writer, called Multi Shaped Beam (MSB), will be presented. Lithography performance results, which are most relevant for mask writing applications, will be disclosed. The MSB technology is an evolutionary development of the matured single Variable Shaped Beam (VSB) technology. An arrangement of Multi Deflection Arrays (MDA) allows operation with multiple shaped beams of variable size, which can be deflected and controlled individually [4]. This evolutionary MSB approach is associated with a lower level of risk and a relatively short time to implementation compared to the known revolutionary concepts [3, 5, 6]. Lithography performance is demonstrated through exposed pattern. Further details of the substrate positioning platform performance will be disclosed. It will become apparent that the MSB operational mode enables lithography on the same and higher performance level compared to single VSB and that there are no specific additional lithography challenges existing beside those which have already been addressed [1].

Comparison of geometric morphometric outline methods in the discrimination of age-related differences in feather shape

PubMed Central

Sheets, H David; Covino, Kristen M; Panasiewicz, Joanna M; Morris, Sara R

2006-01-01

Background Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. Results Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method of outline measurement. Rates of classification were not highly dependent on the number of points used to represent a curve or the manner in which those points were acquired. The new approach to dimensionality reduction, which utilizes a variable number of principal component (PC) axes, produced higher cross-validation assignment rates than either the standard approach of using a fixed number of PC axes or a partial least squares method. Conclusion Classification of specimens based on feather shape was not highly dependent of the details of the method used to capture shape information. The choice of dimensionality reduction approach was more of a factor, and the cross validation rate of assignment may be optimized using the variable number of PC axes method presented herein. PMID:16978414

Measuring spore settling velocity for an improved assessment of dispersal rates in mosses

PubMed Central

Zanatta, Florian; Patiño, Jairo; Lebeau, Frederic; Massinon, Mathieu; Hylander, Kristofer; de Haan, Myriam; Ballings, Petra; Degreef, Jerôme; Vanderpoorten, Alain

2016-01-01

Background and Aims The settling velocity of diaspores is a key parameter for the measurement of dispersal ability in wind-dispersed plants and one of the most relevant parameters in explicit dispersal models, but remains largely undocumented in bryophytes. The settling velocities of moss spores were measured and it was determined whether settling velocities can be derived from spore diameter using Stokes’ Law or if specific traits of spore ornamentation cause departures from theoretical expectations. Methods A fall tower design combined with a high-speed camera was used to document spore settling velocities in nine moss species selected to cover the range of spore diameters within the group. Linear mixed effect models were employed to determine whether settling velocity can be predicted from spore diameter, taking specific variation in shape and surface roughness into account. Key Results Average settling velocity of moss spores ranged from 0·49 to 8·52 cm s–1. There was a significant positive relationship between spore settling velocity and size, but the inclusion of variables of shape and texture of spores in the best-fit models provides evidence for their role in shaping spore settling velocities. Conclusions Settling velocities in mosses can significantly depart from expectations derived from Stokes’ Law. We suggest that variation in spore shape and ornamentation affects the balance between density and drag, and results in different dispersal capacities, which may be correlated with different life-history traits or ecological requirements. Further studies on spore ultrastructure would be necessary to determine the role of complex spore ornamentation patterns in the drag-to-mass ratio and ultimately identify what is the still poorly understood function of the striking and highly variable ornamentation patterns of the perine layer on moss spores. PMID:27296133

Hydrodynamic and sedimentological controls governing formation of fluvial levees

NASA Astrophysics Data System (ADS)

Johnston, G. H.; Edmonds, D. A.; David, S. R.; Czuba, J. A.

2017-12-01

Fluvial levees are familiar features found on the margins of river channels, yet we know little about what controls their presence, height, and shape. These attributes of levees are important because they control sediment transfer from channel to floodplain and flooding patterns along a river system. Despite the familiarity and importance of levees, there is a surprising lack of basic geomorphic data on fluvial levees. Because of this we seek to understand: 1) where along rivers do levees tend to occur?; 2) what geomorphic and hydrodynamic variables control cross-sectional shape of levees? We address these questions by extracting levee shape from LiDAR data and by collecting hydrodynamic and sedimentological data from reaches of the Tippecanoe River, the White River, and the Muscatatuck River, Indiana, USA. Fluvial levees are extracted from a 1.5-m resolution LiDAR bare surface model and compared to hydrological, sedimentological, and geomorphological data from USGS stream gages. We digitized banklines and extracted levee cross-sections to calculate levee slope, taper, height, e-folding length, and e-folding width. To answer the research questions, we performed a multivariable regression between the independent variables—channel geometry, sediment grain size and concentration, flooding conditions, and slope—and the dependent levee variables. We find considerable variation in levee presence and shape in our field data. On the Muscatatuck River levees occur on 30% of the banks compared to 10% on the White River. Moreover, levees on the Muscatatuck are on average 3 times wider than the White River. This is consistent with the observation that the Muscatatuck is finer-grained compared to the White River and points to sedimentology being an important control on levee geomorphology. Future work includes building a morphodynamic model to understand how different hydrodynamic and geomorphic conditions control levee geometry.

Environmental effects on the shape variation of male ultraviolet patterns in the Brimstone butterfly ( Gonepteryx rhamni, Pieridae, Lepidoptera)

NASA Astrophysics Data System (ADS)

Pecháček, Pavel; Stella, David; Keil, Petr; Kleisner, Karel

2014-12-01

The males of the Brimstone butterfly ( Gonepteryx rhamni) have ultraviolet pattern on the dorsal surfaces of their wings. Using geometric morphometrics, we have analysed correlations between environmental variables (climate, productivity) and shape variability of the ultraviolet pattern and the forewing in 110 male specimens of G. rhamni collected in the Palaearctic zone. To start with, we subjected the environmental variables to principal component analysis (PCA). The first PCA axis (precipitation, temperature, latitude) significantly correlated with shape variation of the ultraviolet patterns across the Palaearctic. Additionally, we have performed two-block partial least squares (PLS) analysis to assess co-variation between intraspecific shape variation and the variation of 11 environmental variables. The first PLS axis explained 93 % of variability and represented the effect of precipitation, temperature and latitude. Along this axis, we observed a systematic increase in the relative area of ultraviolet colouration with increasing temperature and precipitation and decreasing latitude. We conclude that the shape variation of ultraviolet patterns on the forewings of male Brimstones is correlated with large-scale environmental factors.

Universality of fragment shapes.

PubMed

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-03-16

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

Determining shapes and dimensions of dental arches for the use of straight-wire arches in lingual technique.

PubMed

Kairalla, Silvana Allegrini; Scuzzo, Giuseppe; Triviño, Tarcila; Velasco, Leandro; Lombardo, Luca; Paranhos, Luiz Renato

2014-01-01

This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D) and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25%)--an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%). T-test revealed differences between males and females in the size of 12 dental arches. The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.

Universality of fragment shapes

PubMed Central

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-01-01

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.

The brown anole dewlap revisited: do predation pressure, sexual selection, and species recognition shape among-population signal diversity?

PubMed Central

Van Damme, Raoul

2018-01-01

Animal signalling structures are amongst the most variable characteristics, as they are subjected to a diversity of selection pressures. A well-known example of a diverse signalling system in the animal kingdom is the dewlap of Anolis lizards. Dewlap characteristics can vary remarkably among and within species, and also between sexes. Although a considerable amount of studies have attempted to disentangle the functional significance of the staggering dewlap diversity in Anolis, the underlying evolutionary processes remain elusive. In this study, we focus on the contribution of biotic selective pressures in shaping geographic variation in dewlap design (size, colour, and pattern) and dewlap display behaviour at the intraspecific level. Notably, we have tried to replicate and extend previously reported results hereof in both sexes of the brown anole lizard (Anolis sagrei). To do this, we assembled a dataset consisting of 17 A. sagrei heterogeneous island populations from the Caribbean and specifically tested whether predation pressure, sexual selection, or species recognition could explain interpopulational variation in an array of dewlap characteristics. Our findings show that in neither males nor females estimates of predation pressure (island size, tail break frequency, model attack rate, presence of predatory Leiocephalus lizards) or sexual selection (sexual size dimorphism) could explain variation in dewlap design. We did find that A. sagrei males from larger islands showed higher dewlap display intensities than males from smaller islands, but the direct connection with predation pressure remains ambiguous and demands further investigation. Last, we could show indirect support for species recognition only in males, as they are more likely to have a ‘spotted’ dewlap pattern when co-occurring with a higher number of syntopic Anolis species. In conclusion, we found overall limited support for the idea that the extensive interpopulational variability in dewlap design and use in A. sagrei is mediated by variation in their biotic environment. We propose a variety of conceptual and methodological explanations for this unexpected finding. PMID:29761044

Aerodynamic Shape Optimization of a Dual-Stream Supersonic Plug Nozzle

NASA Technical Reports Server (NTRS)

Heath, Christopher M.; Gray, Justin S.; Park, Michael A.; Nielsen, Eric J.; Carlson, Jan-Renee

2015-01-01

Aerodynamic shape optimization was performed on an isolated axisymmetric plug nozzle sized for a supersonic business jet. The dual-stream concept was tailored to attenuate nearfield pressure disturbances without compromising nozzle performance. Adjoint-based anisotropic mesh refinement was applied to resolve nearfield compression and expansion features in the baseline viscous grid. Deformed versions of the adapted grid were used for subsequent adjoint-driven shape optimization. For design, a nonlinear gradient-based optimizer was coupled to the discrete adjoint formulation of the Reynolds-averaged Navier- Stokes equations. All nozzle surfaces were parameterized using 3rd order B-spline interpolants and perturbed axisymmetrically via free-form deformation. Geometry deformations were performed using 20 design variables shared between the outer cowl, shroud and centerbody nozzle surfaces. Interior volume grid deformation during design was accomplished using linear elastic mesh morphing. The nozzle optimization was performed at a design cruise speed of Mach 1.6, assuming core and bypass pressure ratios of 6.19 and 3.24, respectively. Ambient flight conditions at design were commensurate with 45,000-ft standard day atmosphere.

Reciprocal-space mapping of epitaxic thin films with crystallite size and shape polydispersity.

PubMed

Boulle, A; Conchon, F; Guinebretière, R

2006-01-01

A development is presented that allows the simulation of reciprocal-space maps (RSMs) of epitaxic thin films exhibiting fluctuations in the size and shape of the crystalline domains over which diffraction is coherent (crystallites). Three different crystallite shapes are studied, namely parallelepipeds, trigonal prisms and hexagonal prisms. For each shape, two cases are considered. Firstly, the overall size is allowed to vary but with a fixed thickness/width ratio. Secondly, the thickness and width are allowed to vary independently. The calculations are performed assuming three different size probability density functions: the normal distribution, the lognormal distribution and a general histogram distribution. In all cases considered, the computation of the RSM only requires a two-dimensional Fourier integral and the integrand has a simple analytical expression, i.e. there is no significant increase in computing times by taking size and shape fluctuations into account. The approach presented is compatible with most lattice disorder models (dislocations, inclusions, mosaicity, ...) and allows a straightforward account of the instrumental resolution. The applicability of the model is illustrated with the case of an yttria-stabilized zirconia film grown on sapphire.

A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

NASA Technical Reports Server (NTRS)

Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

2010-01-01

As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

Phase gradient metasurface with broadband anomalous reflection based on cross-shaped units

NASA Astrophysics Data System (ADS)

Chen, Zhaobin; Deng, Hui; Xiong, Qingxu; Liu, Chen

2018-03-01

It has been pointed out by many documents that a phase gradient metasurface with wideband characteristics can be designed by the unit with a low-quality factor ( Q value). In this paper, a cross-shaped unit with a low-quality factor Q is proposed. By changing the variable parameters of the unit, it is found that the reflection phase of the unit can achieve a stable distribution of phase gradient in the frequency range of 8.0-20.0 GHz. we analyze variation of the electromagnetic field distribution on the unit with frequency and find that the size along electrical field polarization of electromagnetic field distribution area changes with frequency. Based on our design, effective size of electromagnetic field distribution area keeps meeting the subwavelength condition, thus stable phase distribution is gained across broadened bandwidth. It is found by the analysis of the phase gradient metasurface composed of seven units that the metasurface can exhibit anomalous reflection in the wide frequency band of 8.0-20.0 GHz, and the efficiency of abnormal reflection is higher in the range of 10.0-18.0 GHz. The error between the simulation results of abnormal reflection angle and the theoretical result is only - 1.5° to 0.5° after the work of comparison. Therefore, the metasurface designed by the new cross-shaped unit has a good control on the deflection direction of the reflected wave, and shows obvious advantages in widening the bandwidth.

Analysis of Acoustic Access to the Prostate Through the Abdomen and Perineum for Extracorporeal Ablation

NASA Astrophysics Data System (ADS)

Hall, Timothy L.; Hempel, Christopher R.; Sabb, Brian J.; Roberts, William W.

2010-03-01

As part of the development of a noninvasive treatment for BPH using histotripsy, this study aimed to measure acoustic access for extracorporeal ablation of the prostate. Both transabdominal and transperineal approaches were considered. The objective was to measure the size and shape of a transducer aperture that could target the prostate without obstruction. CT images obtained from 17 subjects >56 years of age were used to create 3D reconstructions of the lower abdomen and pelvis. Target locations on the urethra at the base, mid, and apex in the prostate were marked along with a transrectal imaging probe. Evenly space rays spanning were traced from each target location towards the perineum and separately towards the abdomen with the maximum x-ray density encountered along each path recorded. The overall free aperture through the perineum was found to be a triangular shaped region bounded by the lower bones of the pelvis and the transrectal probe varying significantly in size between subjects. The free aperture through the abdomen was wedge shaped limited by the pubis also with great subject to subject variability. Average unblocked fractions of an f/1 transducer to target base, veru, and apex through the perineum were 77.0%, 94.4%, and 99.6%, respectively. Averages targeting through the abdomen were 86.1%, 52.3%, and 11.0%. Acoustic access to the prostate for through the perineum was judged to be feasible.

Henricia djakonovi sp. nov. (Echinodermata, Echinasteridae): a new sea star species from the Sea of Japan.

PubMed

Chichvarkhin, Anton

2017-01-01

A new sea star species, H. djakonovi sp.n., was discovered in Rudnaya Bay in the Sea of Japan. This is a sympatric species of the well-known and common species Henricia pseudoleviuscula Djakonov, 1958. Both species are similar in body size and proportions, shape of skeletal plates, and life coloration, which distinguishes them from the other Henricia species inhabiting the Sea of Japan. Nevertheless, these species can be distinguished by their abactinal spines: in both species, they are short and barrel-like, but the new species is the only Henricia species in Russian waters of the Pacific that possesses such spines with a massive, smooth, bullet-like tip. The spines in H. pseudoleviuscula are crowned with a variable number of well-developed thorns. About half (<50%) of the abactinal pseudopaxillae in the new species are oval, not crescent-shaped as in H. pseudoleviuscula .

Inter- and intrapatient variability of facial nerve response areas in the floor of the fourth ventricle.

PubMed

Bertalanffy, Helmut; Tissira, Nadir; Krayenbühl, Niklaus; Bozinov, Oliver; Sarnthein, Johannes

2011-03-01

Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage. To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa. Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient. Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm). Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.

42 CFR 37.54 - Notification of abnormal radiographic findings.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., abnormality of cardiac shape or size, tuberculosis, lung cancer, or any other significant abnormal findings... shape or size, tuberculosis, cancer, complicated pneumoconiosis, and any other significant abnormal...

Investigation of the Evolution of Crystal Size and Shape during Temperature Cycling and in the Presence of a Polymeric Additive Using Combined Process Analytical Technologies

PubMed Central

2017-01-01

Crystal size and shape can be manipulated to enhance the qualities of the final product. In this work the steady-state shape and size of succinic acid crystals, with and without a polymeric additive (Pluronic P123) at 350 mL, scale is reported. The effect of the amplitude of cycles as well as the heating/cooling rates is described, and convergent cycling (direct nucleation control) is compared to static cycling. The results show that the shape of succinic acid crystals changes from plate- to diamond-like after multiple cycling steps, and that the time required for this morphology change to occur is strongly related to the type of cycling. Addition of the polymer is shown to affect both the final shape of the crystals and the time needed to reach size and shape steady-state conditions. It is shown how this phenomenon can be used to improve the design of the crystallization step in order to achieve more efficient downstream operations and, in general, to help optimize the whole manufacturing process. PMID:28867966

Variable area nozzle for gas turbine engines driven by shape memory alloy actuators

NASA Technical Reports Server (NTRS)

Rey, Nancy M. (Inventor); Miller, Robin M. (Inventor); Tillman, Thomas G. (Inventor); Rukus, Robert M. (Inventor); Kettle, John L. (Inventor); Dunphy, James R. (Inventor); Chaudhry, Zaffir A. (Inventor); Pearson, David D. (Inventor); Dreitlein, Kenneth C. (Inventor); Loffredo, Constantino V. (Inventor)

2001-01-01

A gas turbine engine includes a variable area nozzle having a plurality of flaps. The flaps are actuated by a plurality of actuating mechanisms driven by shape memory alloy (SMA) actuators to vary fan exist nozzle area. The SMA actuator has a deformed shape in its martensitic state and a parent shape in its austenitic state. The SMA actuator is heated to transform from martensitic state to austenitic state generating a force output to actuate the flaps. The variable area nozzle also includes a plurality of return mechanisms deforming the SMA actuator when the SMA actuator is in its martensitic state.

Crystallography of rare galactic honeycomb structure near supernova 1987a

NASA Technical Reports Server (NTRS)

Noever, David A.

1994-01-01

Near supernova 1987a, the rare honeycomb structure of 20-30 galactic bubbles measures 30 x 90 light years. Its remarkable regularity in bubble size suggests a single-event origin which may correlate with the nearby supernova. To test the honeycomb's regularity in shape and size, the formalism of statistical crystallography is developed here for bubble sideness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter and nearest neighbor shapes. Taken together, they predict a highly non-equilibrium structure for the galactic honeycomb which evolves as a bimodal shape distribution without dominant bubble perimeter energy.

Variable flexure-based fluid filter

DOEpatents

Brown, Steve B.; Colston, Jr., Billy W.; Marshall, Graham; Wolcott, Duane

2007-03-13

An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.

Feline vaccine-associated fibrosarcoma induced by aluminium compound in two cats: short communication.

PubMed

Deim, Zoltán; Palmai, Nimród; Cserni, Gábor

2008-03-01

Two cases of feline vaccine-associated fibrosarcoma (FVAF) are reported. The excised tumours were both characterised as well circumscribed, subcutaneous, firm and white with central necrosis. Histopathologically, they consisted of well-differentiated and variably sized and shaped anaplastic cells, characterised by marked nuclear and cellular pleomorphism including giant cells. The mitotic activity was low. Aluminium was demonstrated in the central necrosis and giant cells. Neoplastic cells were positive for vimentin and negative for desmin and cytokeratin. The presence of feline sarcoma virus and feline immunodeficiency virus could not be detected by PCR in either case.

Absorption and scattering of light by nonspherical particles. [in atmosphere

NASA Technical Reports Server (NTRS)

Bohren, C. F.

1986-01-01

Using the example of the polarization of scattered light, it is shown that the scattering matrices for identical, randomly ordered particles and for spherical particles are unequal. The spherical assumptions of Mie theory are therefore inconsistent with the random shapes and sizes of atmospheric particulates. The implications for corrections made to extinction measurements of forward scattering light are discussed. Several analytical methods are examined as potential bases for developing more accurate models, including Rayleigh theory, Fraunhoffer Diffraction theory, anomalous diffraction theory, Rayleigh-Gans theory, the separation of variables technique, the Purcell-Pennypacker method, the T-matrix method, and finite difference calculations.

Gender differences of foot characteristics in older Japanese adults using a 3D foot scanner.

PubMed

Saghazadeh, Mahshid; Kitano, Naruki; Okura, Tomohiro

2015-01-01

Knowledge of gender differences in foot shape assists shoe manufactures with designing appropriate shoes for men and women. Although gender differences in foot shapes are relatively known among young men and women, less is known about how the older men and women's feet differ in shape. A recent development in foot shape assessment is the use of 3D foot scanners. To our knowledge this technology has yet to be used to examine gender differences in foot shape of Japanese older adults. This cross-sectional study included 151 older men (74.5 ± 5.6 years) and 140 older women (73.9 ± 5.1 years) recruited in Kasama City, Japan. Foot variables were measured in sitting and standing positions using Dream GP Incorporated's 3D foot scanner, Footstep PRO (Osaka, Japan). Scores were analyzed as both raw and normalized to truncated foot length using independent samples t-test and analysis of covariance, respectively. In men, the measurement values for navicular height, first and fifth toe and instep heights, ball and heel width, ball girth, arch height index (just standing), arch rigidity index and instep girth were significantly greater than the women's, whereas the first toe angle, in both sitting and standing positions was significantly smaller. However, after normalizing, the differences in ball width, heel width, height of first and fifth toes in both sitting and standing and ball girth in sitting position were nonsignificant. According to Cohen's d, among all the foot variables, the following had large effect sizes in both sitting and standing positions: truncated foot length, instep, navicular height, foot length, ball girth, ball width, heel width and instep girth. This study provides evidence of anthropometric foot variations between older men and women. These differences need to be considered when manufacturing shoes for older adults.

Internal Tooth Structure and Burial Practices: Insights into the Neolithic Necropolis of Gurgy (France, 5100-4000 cal. BC).

PubMed

Le Luyer, Mona; Coquerelle, Michael; Rottier, Stéphane; Bayle, Priscilla

2016-01-01

Variations in the dental crown form are widely studied to interpret evolutionary changes in primates as well as to assess affinities among human archeological populations. Compared to external metrics of dental crown size and shape, variables including the internal structures such as enamel thickness, tissue proportions, and the three-dimensional shape of enamel-dentin junction (EDJ), have been described as powerful measurements to study taxonomy, phylogenetic relationships, dietary, and/or developmental patterns. In addition to providing good estimate of phenotypic distances within/across archeological samples, these internal tooth variables may help to understand phylogenetic, functional, and developmental underlying causes of variation. In this study, a high resolution microtomographic-based record of upper permanent second molars from 20 Neolithic individuals of the necropolis of Gurgy (France) was applied to evaluate the intrasite phenotypic variation in crown tissue proportions, thickness and distribution of enamel, and EDJ shape. The study aims to compare interindividual dental variations with burial practices and chronocultural parameters, and suggest underlying causes of these dental variations. From the non-invasive characterization of internal tooth structure, differences have been found between individuals buried in pits with alcove and those buried in pits with container and pits with wattling. Additionally, individuals from early and recent phases of the necropolis have been distinguished from those of the principal phase from their crown tissue proportions and EDJ shape. The results suggest that the internal tooth structure may be a reliable proxy to track groups sharing similar chronocultural and burial practices. In particular, from the EDJ shape analysis, individuals buried in an alcove shared a reduction of the distolingual dentin horn tip (corresponding to the hypocone). Environmental, developmental and/or functional underlying causes might be suggested for the origin of phenotypic differences shared by these individuals buried in alcoves.

Nursing Unit Design, Nursing Staff Communication Networks, and Patient Falls: Are They Related?

PubMed

Brewer, Barbara B; Carley, Kathleen M; Benham-Hutchins, Marge; Effken, Judith A; Reminga, Jeffrey

2018-01-01

The purpose of this research is to (1) investigate the impact of nursing unit design on nursing staff communication patterns and, ultimately, on patient falls in acute care nursing units; and (2) evaluate whether differences in fall rates, if found, were associated with the nursing unit physical structure (shape) or size. Nursing staff communication and nursing unit design are frequently linked to patient safety outcomes, yet little is known about the impact of specific nursing unit designs on nursing communication patterns that might affect patient falls. An exploratory longitudinal correlational design was used to measure nursing unit communication structures using social network analysis techniques. Data were collected 4 times over a 7-month period. Floor plans were used to determine nursing unit design. Fall rates were provided by hospital coordinators. An analysis of covariance controlling for hospitals resulted in a statistically significant interaction of unit shape and size (number of beds). The interaction occurred when medium- and large-sized racetrack-shaped units intersected with medium- and large-sized cross-shaped units. The results suggest that nursing unit design shape impacts nursing communication patterns, and the interaction of shape and size may impact patient falls. How those communication patterns affect patient falls should be considered when planning hospital construction of nursing care units.

Shape-Controlled Synthesis of Isotopic Yttrium-90-Labeled Rare Earth Fluoride Nanocrystals for Multimodal Imaging.

PubMed

Paik, Taejong; Chacko, Ann-Marie; Mikitsh, John L; Friedberg, Joseph S; Pryma, Daniel A; Murray, Christopher B

2015-09-22

Isotopically labeled nanomaterials have recently attracted much attention in biomedical research, environmental health studies, and clinical medicine because radioactive probes allow the elucidation of in vitro and in vivo cellular transport mechanisms, as well as the unambiguous distribution and localization of nanomaterials in vivo. In addition, nanocrystal-based inorganic materials have a unique capability of customizing size, shape, and composition; with the potential to be designed as multimodal imaging probes. Size and shape of nanocrystals can directly influence interactions with biological systems, hence it is important to develop synthetic methods to design radiolabeled nanocrystals with precise control of size and shape. Here, we report size- and shape-controlled synthesis of rare earth fluoride nanocrystals doped with the β-emitting radioisotope yttrium-90 ((90)Y). Size and shape of nanocrystals are tailored via tight control of reaction parameters and the type of rare earth hosts (e.g., Gd or Y) employed. Radiolabeled nanocrystals are synthesized in high radiochemical yield and purity as well as excellent radiolabel stability in the face of surface modification with different polymeric ligands. We demonstrate the Cerenkov radioluminescence imaging and magnetic resonance imaging capabilities of (90)Y-doped GdF3 nanoplates, which offer unique opportunities as a promising platform for multimodal imaging and targeted therapy.

Cyclosporine a loaded solid lipid nanoparticles: optimization of formulation, process variable and characterization.

PubMed

Varia, Jigisha K; Dodiya, Shamsunder S; Sawant, Krutika K

2008-01-01

Solid lipid nanoparticles (SLNs) loaded with Cyclosporine A using glyceryl monostearate (GMS) and glyceryl palmitostearate (GPS) as lipid matrices were prepared by melt-homogenization using high-pressure homogenizer. Various process parameters such as homogenization pressure, homogenization cycles and formulation parameters such as ratio of drug: lipid, emulsifier: lipid and emulsifier: co-emulsifier were optimized using particle size and entrapment efficiencies as the dependent variables. The mean particle size of optimized batches of the GMS SLN and GPS SLN were found to be 131 nm and 158 nm and their entrapment efficiencies were 83 +/- 3.08% and 97 +/- 2.59% respectively. To improve the handling processing and stability of the prepared SLNs, the SLN dispersions were spray dried and its effect on size and reconstitution parameters were evaluated. The spray drying of SLNs did not significantly alter the size of SLNs and they exhibited good redispersibility. Solid state studies such as Infra Red Spectroscopy and Differential Scanning Calorimetry indicated absence of any chemical interaction between Cyclosporine A and the lipids. Scanning Electron Microscopy of optimized formulations showed spherical shape with smooth and non porous surface. In vitro release studies revealed that GMS based SLNs released the drug faster (41.12% in 20 hours) than GPS SLNs (7.958% in 20 hours). Release of Cyclosporine A from GMS SLN followed Higuchi equation better than first order while release from GPS SLN followed first order better than Higuchi model.

Head shape evolution in Tropidurinae lizards: does locomotion constrain diet?

PubMed

Kohlsdorf, T; Grizante, M B; Navas, C A; Herrel, A

2008-05-01

Different components of complex integrated systems may be specialized for different functions, and thus the selective pressures acting on the system as a whole may be conflicting and can ultimately constrain organismal performance and evolution. The vertebrate cranial system is one of the most striking examples of a complex system with several possible functions, being associated to activities as different as locomotion, prey capture, display and defensive behaviours. Therefore, selective pressures on the cranial system as a whole are possibly complex and may be conflicting. The present study focuses on the influence of potentially conflicting selective pressures (diet vs. locomotion) on the evolution of head shape in Tropidurinae lizards. For example, the expected adaptations leading to flat heads and bodies in species living on vertical structures may conflict with the need for improved bite performance associated with the inclusion of hard or tough prey into the diet, a common phenomenon in Tropidurinae lizards. Body size and six variables describing head shape were quantified in preserved specimens of 23 species, and information on diet and substrate usage was obtained from the literature. No phylogenetic signal was observed in the morphological data at any branch length tested, suggesting adaptive evolution of head shape in Tropidurinae. This pattern was confirmed by both factor analysis and independent contrast analysis, which suggested adaptive co-variation between the head shape and the inclusion of hard prey into the diet. In contrast to our expectations, habitat use did not constrain or drive head shape evolution in the group.

Separation of plastics by froth flotation. The role of size, shape and density of the particles.

PubMed

Pita, Fernando; Castilho, Ana

2017-02-01

Over the last few years, new methods for plastic separation in mining have been developed. Froth flotation is one of these techniques, which is based on hydrophobicity differences between particles. Unlike minerals, most of the plastics are naturally hydrophobic, thus requiring the addition of chemicals that promote the selective wettability of one of its components, for a flotation separation. The floatability of six granulated post-consumer plastic - Polystyrene (PS), Polymethyl methacrylate (PMMA), Polyethylene Terephthalate (PET-S, PET-D) and Polyvinyl Chloride (PVC-M, PVC-D) - in the presence of tannic acid (wetting agent), and the performance of the flotation separation of five bi-component plastic mixtures - PS/PMMA, PS/PET-S, PS/PET-D, PS/PVC-M and PS/PVC-D - were evaluated. Moreover, the effect of the contact angle, density, size and shape of the particles was also analysed. Results showed that all plastics were naturally hydrophobic, with PS exhibiting the highest floatability. The contact angle and the flotation recovery of six plastics decreased with increasing tannic acid concentration, occurring depression of plastics at very low concentrations. Floatability differed also with the size and shape of plastic particles. For regular-shaped plastics (PS, PMMA and PVC-D) floatability decreased with the increase of particle size, while for lamellar-shaped particles (PET-D) floatability was slightly greater for coarser particles. Thus, plastic particles with small size, lamellar shape and low density present a greater floatability. The quality of separation varied with the mixture type, depending not only on the plastics hydrophobicity, but also on the size, density and shape of the particles, i.e. the particle weight. Flotation separation of plastics can be enhanced by differences in hydrophobicity. In addition, flotation separation improves if the most hydrophobic plastic, that floats, has a lamellar shape and lower density and if the most hydrophilic plastic, that sinks, has a regular shape and higher density. The results obtained show that froth flotation is a potential method for plastics separation, in particular for plastics with particle size greater than 2.0mm. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design and fabrication of nano-imprint templates using unique pattern transforms and primitives

NASA Astrophysics Data System (ADS)

MacDonald, Susan; Mellenthin, David; Rentzsch, Kevin; Kramer, Kenneth; Ellenson, James; Hostetler, Tim; Enck, Ron

2005-11-01

Increasing numbers of MEMS, photonic, and integrated circuit manufacturers are investigating the use of Nano-imprint Lithography or Step and Flash Imprint Lithography (SFIL) as a lithography choice for making various devices and products. Their main interests in using these technologies are the lack of aberrations inherent in traditional optical reduction lithography, and the relative low cost of imprint tools. Since imprint templates are at 1X scale, the small sizes of these structures have necessitated the use of high-resolution 50KeV, and 100KeV e-beam lithography tools to build these templates. For MEMS and photonic applications, the structures desired are often circles, arches, and other non-orthogonal shapes. It has long been known that both 50keV, and especially 100keV e-beam lithography tools are extremely accurate, and can produce very high resolution structures, but the trade off is long write times. The main drivers in write time are shot count and stage travel. This work will show how circles and other non-orthogonal shapes can be produced with a 50KeV Variable Shaped Beam (VSB) e-beam lithography system using unique pattern transforms and primitive shapes, while keeping the shot count and write times under control. The quality of shapes replicated into the resist on wafer using an SFIL tool will also be presented.

Sonographic findings of ruptured epidermal inclusion cysts in superficial soft tissue: emphasis on shapes, pericystic changes, and pericystic vascularity.

PubMed

Jin, Wook; Ryu, Kyung Nam; Kim, Gou Young; Kim, Hyun Cheol; Lee, Jae Hoon; Park, Ji Seon

2008-02-01

The purpose of this study was to retrospectively evaluate the sonographic findings of ruptured epidermal inclusion cysts in superficial soft tissue, with an emphasis on shapes, pericystic changes, and pericystic vascularity. The cases of 61 patients with surgically confirmed epidermal inclusion cysts were reviewed, and 13 patients were found to have ruptured cysts. The Ethics Committees of our institutions did not require patient approval or informed patient consent for this retrospective study. We evaluated the shapes, sizes, locations, pericystic changes, and pericystic vascularity for the 13 cases. The shapes of the ruptured epidermal inclusion cysts were classified into 3 types: with lobulations (type I, 2 cases), with protrusions (type II, 8 cases), and with abscess pocket formations (type III, 3 cases). The mean long diameter of the cysts was 3 cm. Common sites of ruptured epidermal inclusion cysts were the plantar surface of the metatarsophalangeal joint (4 cases) and buttocks (3 cases). Pericystic changes were noted in all of the type II and III cysts. Increased vascularity on color Doppler sonography was prominent in 3 type II cysts and 3 type III cysts. Deep abscess formation was noted in the epidermal inclusion cysts, especially for the type III cysts. A ruptured epidermal inclusion cyst visualized by sonography had variable shapes; the sonographic findings can be useful for obtaining a correct diagnosis of a ruptured epidermal inclusion cyst.

Effects of Shapes of Solute Molecules on Diffusion: A Study of Dependences on Solute Size, Solvent, and Temperature.

PubMed

Chan, T C; Li, H T; Li, K Y

2015-12-24

Diffusivities of basically linear, planar, and spherical solutes at infinite dilution in various solvents are studied to unravel the effects of solute shapes on diffusion. On the basis of the relationship between the reciprocal of diffusivity and the molecular volume of solute molecules with similar shape in a given solvent at constant temperature, the diffusivities of solutes of equal molecular volume but different shapes are evaluated and the effects due to different shapes of two equal-sized solute molecules on diffusion are determined. It is found that the effects are dependent on the size of the solute pairs studied. Evidence of the dependence of the solute-shape effects on solvent properties is also demonstrated and discussed. Here, some new diffusion data of aromatic compounds in methanol at different temperatures are reported. The result for methanol in this study indicates that the effects of solute shape on diffusivity are only weakly dependent on temperature.

Variable stiffness mechanisms with SMA actuators

NASA Astrophysics Data System (ADS)

Siler, Damin J.; Demoret, Kimberly B. J.

1996-05-01

Variable stiffness is a new branch of smart structures development with several applications related to aircraft. Previous research indicates that temporarily reducing the stiffness of an airplane wing can decrease control actuator sizing and improve aeroelastic roll performance. Some smart materials like shape memory alloys (SMA) can change their material stiffness properties, but they tend to gain stiffness in their `power on' state. An alternative is to integrate mechanisms into a structure and change stiffness by altering boundary conditions and structural load paths. An innovative concept for an axial strut mechanism was discovered as part of research into variable stiffness. It employs SMA springs (specifically Ni-Ti) in a way that reduces overall stiffness when the SMA springs gain stiffness. A simplified mathematical model for static analysis was developed, and a 70% reduction in stiffness was obtained for a particular selection of springs. The small force capacity of commercially available SMA springs limits the practicality of this concept for large load applications. However, smart material technology is still immature, and future advances may permit development of a heavy-duty, variable stiffness strut that is small and light enough for use in aircraft structures.

Combining Airborne and Lidar Measurements for Attribution of Aerosol Layers

NASA Astrophysics Data System (ADS)

Nikandrova, A.; Väänänen, R.; Tabakova, K.; Kerminen, V. M.; O'Connor, E.

2016-12-01

The aim of this work was to identify discrete aerosol layers and diagnose their origin, investigate the strength of mixing within the free-troposphere and with the boundary layer (BL), and understand the impact that mixing has on local and long-range transport of aerosol. For these purposes we combined airborne in-situ aerosol measurements with data obtained by a High Spectral Resolution Lidar (HSRL). The HSRL was deployed in Hyytiälä, Southern Finland, from January to September 2014 as a part of the US DoE ARM (Atmospheric Radiation Measurement) Mobile Facility during the BAECC (Biogenic Aerosols - Effects on Cloud and Climate) Campaign. Two airborne campaigns took place in April and August 2014 during the BAECC campaign. The vertical profile of backscatter coefficient from the HSRL was used to diagnose the location and depth of significant aerosol layers in the atmosphere. Frequently, in addition to the BL, one or two tropospheric layers were identified. In-situ measurements of the aerosol size distribution in these layers were obtained from a Scanning Mobility Particle Sizer (SMPS) and Optical Particle Sizer (OPS), that were installed on board the aircraft; these measurements were combined to cover sizes ranging from 10 nm to 10 µm. As expected, the highest number concentration of aerosol particles at all size ranges was found predominantly in the BL. Many upper layers had size distributions with a similar shape to that in the BL but with overall lower concentrations attributed to dilution of particles into a large volume of air. Hence, these layers were likely of very similar origin to the air in the BL and presumably were the result of lofted residual layers. Intervening layers however, could contain markedly different distribution shapes, which could be attributed to both different air mass origins, and different ambient relative humidity. Potential for mixing between two discreet elevated layers was often seen as a thin interface layer, which exhibited a combination of properties from both layers. Strong turbulent mixing ensured lower variability in the size distribution in the BL on short timescales, with more variability seen in the free troposphere. 96-hour back trajectories from multiple altitudes were used to diagnose the air mass origin of each discrete layer.

The Interannual Stability of Cumulative Frequency Distributions for Convective System Size and Intensity

NASA Technical Reports Server (NTRS)

Mohr, Karen I.; Molinari, John; Thorncroft, Chris

2009-01-01

The characteristics of convective system populations in West Africa and the western Pacific tropical cyclone basin were analyzed to investigate whether interannual variability in convective activity in tropical continental and oceanic environments is driven by variations in the number of events during the wet season or by favoring large and/or intense convective systems. Convective systems were defined from Tropical Rainfall Measuring Mission (TRMM) data as a cluster of pixels with an 85-GHz polarization-corrected brightness temperature below 255 K and with an area of at least 64 square kilometers. The study database consisted of convective systems in West Africa from May to September 1998-2007, and in the western Pacific from May to November 1998-2007. Annual cumulative frequency distributions for system minimum brightness temperature and system area were constructed for both regions. For both regions, there were no statistically significant differences between the annual curves for system minimum brightness temperature. There were two groups of system area curves, split by the TRMM altitude boost in 2001. Within each set, there was no statistically significant interannual variability. Subsetting the database revealed some sensitivity in distribution shape to the size of the sampling area, the length of the sample period, and the climate zone. From a regional perspective, the stability of the cumulative frequency distributions implied that the probability that a convective system would attain a particular size or intensity does not change interannually. Variability in the number of convective events appeared to be more important in determining whether a year is either wetter or drier than normal.

Percolation in three-dimensional fracture networks for arbitrary size and shape distributions

NASA Astrophysics Data System (ADS)

Thovert, J.-F.; Mourzenko, V. V.; Adler, P. M.

2017-04-01

The percolation threshold of fracture networks is investigated by extensive direct numerical simulations. The fractures are randomly located and oriented in three-dimensional space. A very wide range of regular, irregular, and random fracture shapes is considered, in monodisperse or polydisperse networks containing fractures with different shapes and/or sizes. The results are rationalized in terms of a dimensionless density. A simple model involving a new shape factor is proposed, which accounts very efficiently for the influence of the fracture shape. It applies with very good accuracy in monodisperse or moderately polydisperse networks, and provides a good first estimation in other situations. A polydispersity index is shown to control the need for a correction, and the corrective term is modelled for the investigated size distributions.

A horse's eye view: size and shape discrimination compared with other mammals.

PubMed

Tomonaga, Masaki; Kumazaki, Kiyonori; Camus, Florine; Nicod, Sophie; Pereira, Carlos; Matsuzawa, Tetsuro

2015-11-01

Mammals have adapted to a variety of natural environments from underwater to aerial and these different adaptations have affected their specific perceptive and cognitive abilities. This study used a computer-controlled touchscreen system to examine the visual discrimination abilities of horses, particularly regarding size and shape, and compared the results with those from chimpanzee, human and dolphin studies. Horses were able to discriminate a difference of 14% in circle size but showed worse discrimination thresholds than chimpanzees and humans; these differences cannot be explained by visual acuity. Furthermore, the present findings indicate that all species use length cues rather than area cues to discriminate size. In terms of shape discrimination, horses exhibited perceptual similarities among shapes with curvatures, vertical/horizontal lines and diagonal lines, and the relative contributions of each feature to perceptual similarity in horses differed from those for chimpanzees, humans and dolphins. Horses pay more attention to local components than to global shapes. © 2015 The Author(s).

A finite element simulation of sound attenuation in a finite duct with a peripherally variable liner

NASA Technical Reports Server (NTRS)

Watson, W. R.

1977-01-01

Using multimodal analysis, a variational finite element method is presented for analyzing sound attenuation in a three-dimensional finite duct with a peripherally variable liner in the absence of flow. A rectangular element, with cubic shaped functions, is employed. Once a small portion of a peripheral liner is removed, the attenuation rate near the frequency where maximum attenuation occurs drops significantly. The positioning of the liner segments affects the attenuation characteristics of the liner. Effects of the duct termination are important in the low frequency ranges. The main effect of peripheral variation of the liner is a broadening of the attenuation characteristics in the midfrequency range. Because of matrix size limitations of the presently available computer program, the eigenvalue equations should be solved out of core in order to handle realistic sources.

Low-order modeling of internal heat transfer in biomass particle pyrolysis

DOE PAGES

Wiggins, Gavin M.; Daw, C. Stuart; Ciesielski, Peter N.

2016-05-11

We present a computationally efficient, one-dimensional simulation methodology for biomass particle heating under conditions typical of fast pyrolysis. Our methodology is based on identifying the rate limiting geometric and structural factors for conductive heat transport in biomass particle models with realistic morphology to develop low-order approximations that behave appropriately. Comparisons of transient temperature trends predicted by our one-dimensional method with three-dimensional simulations of woody biomass particles reveal good agreement, if the appropriate equivalent spherical diameter and bulk thermal properties are used. Here, we conclude that, for particle sizes and heating regimes typical of fast pyrolysis, it is possible to simulatemore » biomass particle heating with reasonable accuracy and minimal computational overhead, even when variable size, aspherical shape, anisotropic conductivity, and complex, species-specific internal pore geometry are incorporated.« less

Low-Order Modeling of Internal Heat Transfer in Biomass Particle Pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiggins, Gavin M.; Ciesielski, Peter N.; Daw, C. Stuart

2016-06-16

We present a computationally efficient, one-dimensional simulation methodology for biomass particle heating under conditions typical of fast pyrolysis. Our methodology is based on identifying the rate limiting geometric and structural factors for conductive heat transport in biomass particle models with realistic morphology to develop low-order approximations that behave appropriately. Comparisons of transient temperature trends predicted by our one-dimensional method with three-dimensional simulations of woody biomass particles reveal good agreement, if the appropriate equivalent spherical diameter and bulk thermal properties are used. We conclude that, for particle sizes and heating regimes typical of fast pyrolysis, it is possible to simulate biomassmore » particle heating with reasonable accuracy and minimal computational overhead, even when variable size, aspherical shape, anisotropic conductivity, and complex, species-specific internal pore geometry are incorporated.« less

Regulating positioning and orientation of mitotic spindles via cell size and shape

NASA Astrophysics Data System (ADS)

Li, Jingchen; Jiang, Hongyuan

2018-01-01

Proper location of the mitotic spindle is critical for chromosome segregation and the selection of the cell division plane. However, how mitotic spindles sense cell size and shape to regulate their own position and orientation is still largely unclear. To investigate this question systematically, we used a general model by considering chromosomes, microtubule dynamics, and forces of various molecular motors. Our results show that in cells of various sizes and shapes, spindles can always be centered and oriented along the long axis robustly in the absence of other specified mechanisms. We found that the characteristic time of positioning and orientation processes increases with cell size. Spindles sense the cell size mainly by the cortical force in small cells and by the cytoplasmic force in large cells. In addition to the cell size, the cell shape mainly influences the orientation process. We found that more slender cells have a faster orientation process, and the final orientation is not necessarily along the longest axis but is determined by the radial profile and the symmetry of the cell shape. Finally, our model also reproduces the separation and repositioning of the spindle poles during the anaphase. Therefore, our work provides a general tool for studying the mitotic spindle across the whole mitotic phase.

Large increase in nest size linked to climate change: an indicator of life history, senescence and condition.

PubMed

Møller, Anders Pape; Nielsen, Jan Tøttrup

2015-11-01

Many animals build extravagant nests that exceed the size required for successful reproduction. Large nests may signal the parenting ability of nest builders suggesting that nests may have a signaling function. In particular, many raptors build very large nests for their body size. We studied nest size in the goshawk Accipiter gentilis, which is a top predator throughout most of the Nearctic. Both males and females build nests, and males provision their females and offspring with food. Nest volume in the goshawk is almost three-fold larger than predicted from their body size. Nest size in the goshawk is highly variable and may reach more than 600 kg for a bird that weighs ca. 1 kg. While 8.5% of nests fell down, smaller nests fell down more often than large nests. There was a hump-shaped relationship between nest volume and female age, with a decline in nest volume late in life, as expected for senescence. Clutch size increased with nest volume. Nest volume increased during 1977-2014 in an accelerating fashion, linked to increasing spring temperature during April, when goshawks build and start reproduction. These findings are consistent with nest size being a reliable signal of parental ability, with large nest size signaling superior parenting ability and senescence, and also indicating climate warming.

Optical properties of mineral dust aerosol including analysis of particle size, composition, and shape effects, and the impact of physical and chemical processing

NASA Astrophysics Data System (ADS)

Alexander, Jennifer Mary

Atmospheric mineral dust has a large impact on the earth's radiation balance and climate. The radiative effects of mineral dust depend on factors including, particle size, shape, and composition which can all be extremely complex. Mineral dust particles are typically irregular in shape and can include sharp edges, voids, and fine scale surface roughness. Particle shape can also depend on the type of mineral and can vary as a function of particle size. In addition, atmospheric mineral dust is a complex mixture of different minerals as well as other, possibly organic, components that have been mixed in while these particles are suspended in the atmosphere. Aerosol optical properties are investigated in this work, including studies of the effect of particle size, shape, and composition on the infrared (IR) extinction and visible scattering properties in order to achieve more accurate modeling methods. Studies of particle shape effects on dust optical properties for single component mineral samples of silicate clay and diatomaceous earth are carried out here first. Experimental measurements are modeled using T-matrix theory in a uniform spheroid approximation. Previous efforts to simulate the measured optical properties of silicate clay, using models that assumed particle shape was independent of particle size, have achieved only limited success. However, a model which accounts for a correlation between particle size and shape for the silicate clays offers a large improvement over earlier modeling approaches. Diatomaceous earth is also studied as an example of a single component mineral dust aerosol with extreme particle shapes. A particle shape distribution, determined by fitting the experimental IR extinction data, used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the scattering data, the fits are generally better than those obtained using more commonly invoked particle shape distributions. The next goal of this work is to investigate if modeling methods developed in the studies of single mineral components can be generalized to predict the optical properties of more authentic aerosol samples which are complex mixtures of different minerals. Samples of Saharan sand, Iowa loess, and Arizona road dust are used here as test cases. T-matrix based simulations of the authentic samples, using measured particle size distributions, empirical mineralogies, and a priori particle shape models for each mineral component are directly compared with the measured IR extinction spectra and visible scattering profiles. This modeling approach offers a significant improvement over more commonly applied models that ignore variations in particle shape with size or mineralogy and include only a moderate range of shape parameters. Mineral dust samples processed with organic acids and humic material are also studied in order to explore how the optical properties of dust can change after being aged in the atmosphere. Processed samples include quartz mixed with humic material, and calcite reacted with acetic and oxalic acid. Clear differences in the light scattering properties are observed for all three processed mineral dust samples when compared to the unprocessed mineral dust or organic salt products. These interactions result in both internal and external mixtures depending on the sample. In addition, the presence of these organic materials can alter the mineral dust particle shape. Overall, however, these results demonstrate the need to account for the effects of atmospheric aging of mineral dust on aerosol optical properties. Particle shape can also affect the aerodynamic properties of mineral dust aerosol. In order to account for these effects, the dynamic shape factor is used to give a measure of particle asphericity. Dynamic shape factors of quartz are measured by mass and mobility selecting particles and measuring their vacuum aerodynamic diameter. From this, dynamic shape factors in both the transition and vacuum regime can be derived. The measured dynamic shape factors of quartz agree quite well with the spheroidal shape distributions derived through studies of the optical properties.

Bubble Detachment in Variable Gravity Under the Influence of a Non-Uniform Electric Field

NASA Technical Reports Server (NTRS)

Chang, Shinan; Herman, Cila; Iacona, Estelle

2002-01-01

The objective of the study reported in this paper is to investigate the effects of variable, reduced gravity on the formation and detachment behavior of individual air bubbles under the influence of a non-uniform electric field. For this purpose, variable gravity experiments were carried out in parabolic nights. The non-uniform electric field was generated by a spherical electrode and a plate electrode. The effect of the magnitude of the non-uniform electric field and gravity level on bubble formation, development and detachment at an orifice was investigated. An image processing code was developed that allows the measurement of bubble volume, dimensions and contact angle at detachment. The results of this research can be used to explore the possibility of enhancing boiling heat transfer in the variable and low gravity environments by substituting the buoyancy force with a force induced by the electric field. The results of experiments and measurements indicate that the level of gravity significantly affects bubble shape, size and frequency. The electric field magnitude also influences bubble detachment, however, its impact is not as profound as that of variable gravity for the range of electric field magnitudes investigated in the present study.

Microstructure and mesh sensitivities of mesoscale surrogate driving force measures for transgranular fatigue cracks in polycrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castelluccio, Gustavo M.; McDowell, David L.

The number of cycles required to form and grow microstructurally small fatigue cracks in metals exhibits substantial variability, particularly for low applied strain amplitudes. This variability is commonly attributed to the heterogeneity of cyclic plastic deformation within the microstructure, and presents a challenge to minimum life design of fatigue resistant components. Our paper analyzes sources of variability that contribute to the driving force of transgranular fatigue cracks within nucleant grains. We also employ crystal plasticity finite element simulations that explicitly render the polycrystalline microstructure and Fatigue Indicator Parameters (FIPs) averaged over different volume sizes and shapes relative to the anticipatedmore » fatigue damage process zone. Volume averaging is necessary to both achieve description of a finite fatigue damage process zone and to regularize mesh dependence in simulations. Furthermore, results from constant amplitude remote applied straining are characterized in terms of the extreme value distributions of volume averaged FIPs. Grain averaged FIP values effectively mitigate mesh sensitivity, but they smear out variability within grains. Furthermore, volume averaging over bands that encompass critical transgranular slip planes appear to present the most attractive approach to mitigate mesh sensitivity while preserving variability within grains.« less

Microstructure and mesh sensitivities of mesoscale surrogate driving force measures for transgranular fatigue cracks in polycrystals

DOE PAGES

Castelluccio, Gustavo M.; McDowell, David L.

2015-05-22

The number of cycles required to form and grow microstructurally small fatigue cracks in metals exhibits substantial variability, particularly for low applied strain amplitudes. This variability is commonly attributed to the heterogeneity of cyclic plastic deformation within the microstructure, and presents a challenge to minimum life design of fatigue resistant components. Our paper analyzes sources of variability that contribute to the driving force of transgranular fatigue cracks within nucleant grains. We also employ crystal plasticity finite element simulations that explicitly render the polycrystalline microstructure and Fatigue Indicator Parameters (FIPs) averaged over different volume sizes and shapes relative to the anticipatedmore » fatigue damage process zone. Volume averaging is necessary to both achieve description of a finite fatigue damage process zone and to regularize mesh dependence in simulations. Furthermore, results from constant amplitude remote applied straining are characterized in terms of the extreme value distributions of volume averaged FIPs. Grain averaged FIP values effectively mitigate mesh sensitivity, but they smear out variability within grains. Furthermore, volume averaging over bands that encompass critical transgranular slip planes appear to present the most attractive approach to mitigate mesh sensitivity while preserving variability within grains.« less

Quality of the log-geometric distribution extrapolation for smaller undiscovered oil and gas pool size

USGS Publications Warehouse

Chenglin, L.; Charpentier, R.R.

2010-01-01

The U.S. Geological Survey procedure for the estimation of the general form of the parent distribution requires that the parameters of the log-geometric distribution be calculated and analyzed for the sensitivity of these parameters to different conditions. In this study, we derive the shape factor of a log-geometric distribution from the ratio of frequencies between adjacent bins. The shape factor has a log straight-line relationship with the ratio of frequencies. Additionally, the calculation equations of a ratio of the mean size to the lower size-class boundary are deduced. For a specific log-geometric distribution, we find that the ratio of the mean size to the lower size-class boundary is the same. We apply our analysis to simulations based on oil and gas pool distributions from four petroleum systems of Alberta, Canada and four generated distributions. Each petroleum system in Alberta has a different shape factor. Generally, the shape factors in the four petroleum systems stabilize with the increase of discovered pool numbers. For a log-geometric distribution, the shape factor becomes stable when discovered pool numbers exceed 50 and the shape factor is influenced by the exploration efficiency when the exploration efficiency is less than 1. The simulation results show that calculated shape factors increase with those of the parent distributions, and undiscovered oil and gas resources estimated through the log-geometric distribution extrapolation are smaller than the actual values. ?? 2010 International Association for Mathematical Geology.

flexTMS--a novel repetitive transcranial magnetic stimulation device with freely programmable stimulus currents.

PubMed

Gattinger, Norbert; Moessnang, Georg; Gleich, Bernhard

2012-07-01

Transcranial magnetic stimulation (TMS) is able to noninvasively excite neuronal populations due to brief magnetic field pulses. The efficiency and the characteristics of stimulation pulse shapes influence the physiological effect of TMS. However, commercial devices allow only a minimum of control of different pulse shapes. Basically, just sinusoidal and monophasic pulse shapes with fixed pulse widths are available. Only few research groups work on TMS devices with controllable pulse parameters such as pulse shape or pulse width. We describe a novel TMS device with a full-bridge circuit topology incorporating four insulated-gate bipolar transistor (IGBT) modules and one energy storage capacitor to generate arbitrary waveforms. This flexible TMS (flexTMS ) device can generate magnetic pulses which can be adjusted with respect to pulse width, polarity, and intensity. Furthermore, the equipment allows us to set paired pulses with a variable interstimulus interval (ISI) from 0 to 20 ms with a step size of 10  μs. All user-defined pulses can be applied continually with repetition rates up to 30 pulses per second (pps) or, respectively, up to 100 pps in theta burst mode. Offering this variety of flexibility, flexTMS will allow the enhancement of existing TMS paradigms and novel research applications.

Structure-function covariation with nonfeeding ecological variables influences evolution of feeding specialization in Carnivora

PubMed Central

Tseng, Z. Jack; Flynn, John J.

2018-01-01

Skull shape convergence is pervasive among vertebrates. Although this is frequently inferred to indicate similar functional underpinnings, neither the specific structure-function linkages nor the selective environments in which the supposed functional adaptations arose are commonly identified and tested. We demonstrate that nonfeeding factors relating to sexual maturity and precipitation-related arboreality also can generate structure-function relationships in the skulls of carnivorans (dogs, cats, seals, and relatives) through covariation with masticatory performance. We estimated measures of masticatory performance related to ecological variables that covary with cranial shape in the mammalian order Carnivora, integrating geometric morphometrics and finite element analyses. Even after accounting for phylogenetic autocorrelation, cranial shapes are significantly correlated to both feeding and nonfeeding ecological variables, and covariation with both variable types generated significant masticatory performance gradients. This suggests that mechanisms of obligate shape covariation with nonfeeding variables can produce performance changes resembling those arising from feeding adaptations in Carnivora. PMID:29441363

Study of the Size and Shape of Synapses in the Juvenile Rat Somatosensory Cortex with 3D Electron Microscopy

PubMed Central

Rodríguez, José-Rodrigo; DeFelipe, Javier

2018-01-01

Abstract Changes in the size of the synaptic junction are thought to have significant functional consequences. We used focused ion beam milling and scanning electron microscopy (FIB/SEM) to obtain stacks of serial sections from the six layers of the rat somatosensory cortex. We have segmented in 3D a large number of synapses (n = 6891) to analyze the size and shape of excitatory (asymmetric) and inhibitory (symmetric) synapses, using dedicated software. This study provided three main findings. Firstly, the mean synaptic sizes were smaller for asymmetric than for symmetric synapses in all cortical layers. In all cases, synaptic junction sizes followed a log-normal distribution. Secondly, most cortical synapses had disc-shaped postsynaptic densities (PSDs; 93%). A few were perforated (4.5%), while a smaller proportion (2.5%) showed a tortuous horseshoe-shaped perimeter. Thirdly, the curvature was larger for symmetric than for asymmetric synapses in all layers. However, there was no correlation between synaptic area and curvature. PMID:29387782

Study of the Size and Shape of Synapses in the Juvenile Rat Somatosensory Cortex with 3D Electron Microscopy.

PubMed

Santuy, Andrea; Rodríguez, José-Rodrigo; DeFelipe, Javier; Merchán-Pérez, Angel

2018-01-01

Changes in the size of the synaptic junction are thought to have significant functional consequences. We used focused ion beam milling and scanning electron microscopy (FIB/SEM) to obtain stacks of serial sections from the six layers of the rat somatosensory cortex. We have segmented in 3D a large number of synapses ( n = 6891) to analyze the size and shape of excitatory (asymmetric) and inhibitory (symmetric) synapses, using dedicated software. This study provided three main findings. Firstly, the mean synaptic sizes were smaller for asymmetric than for symmetric synapses in all cortical layers. In all cases, synaptic junction sizes followed a log-normal distribution. Secondly, most cortical synapses had disc-shaped postsynaptic densities (PSDs; 93%). A few were perforated (4.5%), while a smaller proportion (2.5%) showed a tortuous horseshoe-shaped perimeter. Thirdly, the curvature was larger for symmetric than for asymmetric synapses in all layers. However, there was no correlation between synaptic area and curvature.

Growth of arrays of oriented epitaxial platinum nanoparticles with controlled size and shape by natural colloidal lithography

DOE PAGES

Komanicky, Vladimir; Barbour, Andi; Lackova, Miroslava; ...

2014-07-05

Here, we developed a method for production of arrays of platinum nanocrystals of controlled size and shape using templates from ordered silica bead monolayers. Silica beads with nominal sizes of 150 and 450 nm were self-assembl into monolayers over strontium titanate single crystal substrates. The monolayers were used as shadow masks for platinum metal deposition on the substrate using the three-step evaporation technique. Produced arrays of epitaxial platinum islands were transformed into nanocrystals by annealing in a quartz tube in nitrogen flow. The shape of particles is determined by the substrate crystallography, while the size of the particles and theirmore » spacing are controlled by the size of the silica beads in the mono- layer mask. As a proof of concept, arrays of platinum nanocrystals of cubooctahedral shape were prepared on (100) strontium titanate substrates. We also characterized the nanocrystal arrays by atomic force microscopy, scanning electron microscopy, and synchrotron X-ray diffraction techniques.« less

Shape Modification and Size Classification of Microcrystalline Graphite Powder as Anode Material for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Wang, Cong; Gai, Guosheng; Yang, Yufen

2018-03-01

Natural microcrystalline graphite (MCG) composed of many crystallites is a promising new anode material for lithium-ion batteries (LiBs) and has received considerable attention from researchers. MCG with narrow particle size distribution and high sphericity exhibits excellent electrochemical performance. A nonaddition process to prepare natural MCG as a high-performance LiB anode material is described. First, raw MCG was broken into smaller particles using a pulverization system. Then, the particles were modified into near-spherical shape using a particle shape modification system. Finally, the particle size distribution was narrowed using a centrifugal rotor classification system. The products with uniform hemispherical shape and narrow size distribution had mean particle size of approximately 9 μm, 10 μm, 15 μm, and 20 μm. Additionally, the innovative pilot experimental process increased the product yield of the raw material. Finally, the electrochemical performance of the prepared MCG was tested, revealing high reversible capacity and good cyclability.

Particle size and shape distributions of hammer milled pine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westover, Tyler Lott; Matthews, Austin Colter; Williams, Christopher Luke

2015-04-01

Particle size and shape distributions impact particle heating rates and diffusion of volatized gases out of particles during fast pyrolysis conversion, and consequently must be modeled accurately in order for computational pyrolysis models to produce reliable results for bulk solid materials. For this milestone, lodge pole pine chips were ground using a Thomas-Wiley #4 mill using two screen sizes in order to produce two representative materials that are suitable for fast pyrolysis. For the first material, a 6 mm screen was employed in the mill and for the second material, a 3 mm screen was employed in the mill. Bothmore » materials were subjected to RoTap sieve analysis, and the distributions of the particle sizes and shapes were determined using digital image analysis. The results of the physical analysis will be fed into computational pyrolysis simulations to create models of materials with realistic particle size and shape distributions. This milestone was met on schedule.« less

Evaluation of Morphological Change and Aggregation Process of Ice Crystals in Frozen Food by Using Fractal Analysis

NASA Astrophysics Data System (ADS)

Koshiro, Yoko; Watanabe, Manabu; Takai, Rikuo; Hagiwara, Tomoaki; Suzuki, Toru

Size and shape of ice crystals in frozen food materials are very important because they affect not only quality of foods but also the viability of industrial processing such as freeze-drying of concentration. In this study, 30%wt sucrose solution is used as test samples. For examining the effect of stabilizerspectine and xantan gum is added to the sucrose solution. They are frozen on the cold stage of microscope to be observed their growing ice crystals under the circumstance of -10°C. Their size and shape are measured and quantitatively evaluated by applying fractal analysis. lce crystal of complicated shape has large fractal dimension, and vice versa. It successflly categorized the ice crystals into two groups; one is a group of large size and complicated shape, and the other is a group of small size and plain shape. The critical crystal size between the two groups is found to become larger with increasing holding time. It suggests a phenomenological model for metamorphoses process of ice crystals. Further, it is indicated that xantan gum is able to suppress the smoothing of ice crystals.

Morphometric Assessment of Convergent Tool Technology and Function during the Early Middle Palaeolithic: The Case of Payre, France

PubMed Central

Détroit, Florent; Coudenneau, Aude; Moncel, Marie-Hélène

2016-01-01

There appears to be little doubt as to the existence of an intentional technological resolve to produce convergent tools during the Middle Palaeolithic. However, the use of these pieces as pointed tools is still subject to debate: i.e., handheld tool vs. hafted tool. Present-day technological analysis has begun to apply new methodologies in order to quantify shape variability and to decipher the role of the morphology of these pieces in relation to function; for instance, geometric morphometric analyses have recently been applied with successful results. This paper presents a study of this type of analysis on 37 convergent tools from level Ga of Payre site (France), dated to MIS 8–7. These pieces are non-standardized knapping products produced by discoidal and orthogonal core technologies. Moreover, macro-wear studies attest to various activities on diverse materials with no evidence of hafting or projectile use. The aim of this paper is to test the geometric morphometric approach on non-standardized artefacts applying the Elliptical Fourier analysis (EFA) to 3D contours and to assess the potential relationship between size and shape, technology and function. This study is innovative in that it is the first time that this method, considered to be a valuable complement for describing technological and functional attributes, is applied to 3D contours of lithic products. Our results show that this methodology ensures a very good degree of accuracy in describing shape variations of the sharp edges of technologically non-standardized convergent tools. EFA on 3D contours indicates variations in deviations of the outline along the third dimension (i.e., dorso-ventrally) and yields quantitative and insightful information on the actual shape variations of tools. Several statistically significant relationships are found between shape variation and use-wear attributes, though the results emphasize the large variability of the shape of the convergent tools, which, in general, does not show a strong direct association with technological features and function. This is in good agreement with the technological context of this chronological period, characterized by a wide diversity of non-standardized tools adapted to multipurpose functions for varied subsistence activities. PMID:27191164

Morphometric Assessment of Convergent Tool Technology and Function during the Early Middle Palaeolithic: The Case of Payre, France.

PubMed

Chacón, M Gema; Détroit, Florent; Coudenneau, Aude; Moncel, Marie-Hélène

2016-01-01

There appears to be little doubt as to the existence of an intentional technological resolve to produce convergent tools during the Middle Palaeolithic. However, the use of these pieces as pointed tools is still subject to debate: i.e., handheld tool vs. hafted tool. Present-day technological analysis has begun to apply new methodologies in order to quantify shape variability and to decipher the role of the morphology of these pieces in relation to function; for instance, geometric morphometric analyses have recently been applied with successful results. This paper presents a study of this type of analysis on 37 convergent tools from level Ga of Payre site (France), dated to MIS 8-7. These pieces are non-standardized knapping products produced by discoidal and orthogonal core technologies. Moreover, macro-wear studies attest to various activities on diverse materials with no evidence of hafting or projectile use. The aim of this paper is to test the geometric morphometric approach on non-standardized artefacts applying the Elliptical Fourier analysis (EFA) to 3D contours and to assess the potential relationship between size and shape, technology and function. This study is innovative in that it is the first time that this method, considered to be a valuable complement for describing technological and functional attributes, is applied to 3D contours of lithic products. Our results show that this methodology ensures a very good degree of accuracy in describing shape variations of the sharp edges of technologically non-standardized convergent tools. EFA on 3D contours indicates variations in deviations of the outline along the third dimension (i.e., dorso-ventrally) and yields quantitative and insightful information on the actual shape variations of tools. Several statistically significant relationships are found between shape variation and use-wear attributes, though the results emphasize the large variability of the shape of the convergent tools, which, in general, does not show a strong direct association with technological features and function. This is in good agreement with the technological context of this chronological period, characterized by a wide diversity of non-standardized tools adapted to multipurpose functions for varied subsistence activities.

A Revised Similarity Law in Botanic Describes the Genesis of the Vulnerability Curve Shape in Vascular Plants

NASA Astrophysics Data System (ADS)

Mrad, A.; Domec, J. C.; Huang, C. W.; Katul, G. G.

2017-12-01

Xylem tissues are specialized in offering the least possible resistance to water flow. However, this is not guaranteed when ascending sap reaches large negative pressures during periods of water stress when embolism within the xylem occurs, an inevitable step toward potential drought-induced mortality. Ongoing research into changing forest patterns and plant survival due to droughts rarely dispute the significance of Vulnerability Curves (VCs), plots that feature loss in relative conductance with declining liquid pressure (ψ). While Earth-Systems models routinely employ various VC functions, the theoretical underpinnings describing their shape remains lacking. VCs are the outcome of microscopic phenomena describing embolism formation, bubble-scale xylem properties allowing embolism spread, and hydraulic processes that dictate the water potential along the flow path. The work here explores how the upscaled version of these gives rise to popular mathematical shapes used to describe VC measurements: The Logistic and Weibull exceedance equations. Each of these two captures a distinct type of embolism spread: The Logistic VC arises when the probability that embolized vessels interact with intact ones describe embolism spread as water pressure decreases (labeled as a similarity law in botanic [1]). The Weibull VC arises when the aforementioned description includes the effects of ψ explicitly. Variability in xylem properties along the flow path is explored analytically using novel approaches borrowed from `super-statistics' and numerical simulations. The numerical simulations intend to single out which xylem network property is significant in describing the VC shape. The model results corroborate previous research (experimental and 3-dimensional high-resolution simulations) on the effect of vessel size and network topology. It is shown that (i) initial embolism locations alter air-seeding pressure and VC slope; (ii) redundancy and size variations decrease bubble propagation probability with decreasing ψ; and (iii) varying network properties spatially along the flow path delays total loss of conductance. The implications of these findings to linking VC shape to plant traits and the on-going debate about `r' vs `s' shape VCs are highlighted.

The natural channel of Brandywine Creek, Pennsylvania

USGS Publications Warehouse

Wolman, M.G.

1955-01-01

This study of the channel of Brandy wine Creek, Pennsylvania, consists of three parts. The first is an analysis of the changes which take place in the width, depth, velocity, slope of the water surface, suspended load, and roughness factor with changing discharge below the bankfull stage at each of several widely separated cross sections of the channel. Expressed as functions of the discharge, it is found that the variables behave systematically. In every section studied, as the discharge increases, the velocity increases to about the 0.6 power, depth to the 0.4, and load to the 2.0 power of the discharge. The roughness decreases to the 0.2 power of the discharge. The relative magnitudes and the direction of these variations are similar to those which have been observed in other rivers in the United States, primarily in the West. Some modifications of the hypotheses applicable to the western rivers are probably required because on Brandywine Creek the difference between the materials on the bed and in the banks is considerably greater than it is on most of the western rivers studied. In the second part of the paper the progressive changes of the same variables in the downstream direction with increasing discharge at a given frequency are described. Despite the disorderly appearance of the stream, it is found that the variables display a progressive, orderly change in the downstream direction when traced from the headwater tributaries through the trunk stream of Brandywine Creek. At a given frequency of flow, width increases with discharge to about the 0.5 power. Depth increases downstream somewhat less rapidly, while the slope and roughness both decrease in the downstream direction. Despite a decrease in the size of the material on the bed, both the mean velocity and the mean bed velocity increase downstream. The rates of change of these variables are in close accord with the changes observed on rivers flowing in alluvium and in stable irrigation canals. These relationships hold for all flows up to the bankfull stage. Analysis of the streamflow records indicates that the annual maximum discharge equals or exceeds the bankfull stage roughly once every 2 years. The regularity in the behavior of the variables with changing discharges both at-a-station and in the downstream direction and the similar rates of change of the variables on Brandywine Creek and in stable irrigation canals suggest the existence of a quasi-equilibrium in the channel of the creek. Part three of this study is concerned with this concept of equilibrium in streams. By analogy with canals and with several rivers in diverse regions of the United States it may be concluded that this quasi-equilibrium is closely related to the discharge, and to the concentration of the suspended load. The shape and longitudinal profile of the channel are determined by these two independent factors which operate within the limits set by the local geology. The latter determines the initial size, shape, and resistance of the material provided to the channel. The existence of a quasi-equilibrium among the variables studied suggests that most reaches on Brandywine Creek are at grade. This is true if the term "grade," when applied to natural rivers, is synonymous with quasi-equilibrium. The adjustability of the variables in the channel rather than the stability of any particular shape or longitudinal profile of the channel is emphasized when t

Size-dependent adhesion energy of shape-selected Pd and Pt nanoparticles

NASA Astrophysics Data System (ADS)

Ahmadi, M.; Behafarid, F.; Cuenya, B. Roldan

2016-06-01

Thermodynamically stable shape-selected Pt and Pd nanoparticles (NPs) were synthesized via inverse micelle encapsulation and a subsequent thermal treatment in vacuum above 1000 °C. The majority of the Pd NPs imaged via scanning tunneling microscopy (STM) had a truncated octahedron shape with (111) top and interfacial facets, while the Pt NPs were found to adopt a variety of shapes. For NPs of identical shape for both material systems, the NP-support adhesion energy calculated based on STM data was found to be size-dependent, with large NPs (e.g. ~6 nm) having lower adhesion energies than smaller NPs (e.g. ~1 nm). This phenomenon was rationalized based on support-induced strain that for larger NPs favors the formation of lattice dislocations at the interface rather than a lattice distortion that may propagate through the smaller NPs. In addition, identically prepared Pt NPs of the same shape were found to display a lower adhesion energy compared to Pd NPs. While in both cases, a transition from a lattice distortion to interface dislocations is expected to occur with increasing NP size, the higher elastic energy in Pt leads to a lower transition size, which in turn lowers the adhesion energy of Pt NPs compared to Pd.Thermodynamically stable shape-selected Pt and Pd nanoparticles (NPs) were synthesized via inverse micelle encapsulation and a subsequent thermal treatment in vacuum above 1000 °C. The majority of the Pd NPs imaged via scanning tunneling microscopy (STM) had a truncated octahedron shape with (111) top and interfacial facets, while the Pt NPs were found to adopt a variety of shapes. For NPs of identical shape for both material systems, the NP-support adhesion energy calculated based on STM data was found to be size-dependent, with large NPs (e.g. ~6 nm) having lower adhesion energies than smaller NPs (e.g. ~1 nm). This phenomenon was rationalized based on support-induced strain that for larger NPs favors the formation of lattice dislocations at the interface rather than a lattice distortion that may propagate through the smaller NPs. In addition, identically prepared Pt NPs of the same shape were found to display a lower adhesion energy compared to Pd NPs. While in both cases, a transition from a lattice distortion to interface dislocations is expected to occur with increasing NP size, the higher elastic energy in Pt leads to a lower transition size, which in turn lowers the adhesion energy of Pt NPs compared to Pd. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02166b

Mechanics of Fluid-Filled Interstitial Gaps. II. Gap Characteristics in Xenopus Embryonic Ectoderm.

PubMed

Barua, Debanjan; Parent, Serge E; Winklbauer, Rudolf

2017-08-22

The ectoderm of the Xenopus embryo is permeated by a network of channels that appear in histological sections as interstitial gaps. We characterized this interstitial space by measuring gap sizes, angles formed between adjacent cells, and curvatures of cell surfaces at gaps. From these parameters, and from surface-tension values measured previously, we estimated the values of critical mechanical variables that determine gap sizes and shapes in the ectoderm, using a general model of interstitial gap mechanics. We concluded that gaps of 1-4 μm side length can be formed by the insertion of extracellular matrix fluid at three-cell junctions such that cell adhesion is locally disrupted and a tension difference between cell-cell contacts and the free cell surface at gaps of 0.003 mJ/m 2 is generated. Furthermore, a cell hydrostatic pressure of 16.8 ± 1.7 Pa and an interstitial pressure of 3.9 ± 3.6 Pa, relative to the central blastocoel cavity of the embryo, was found to be consistent with the observed gap size and shape distribution. Reduction of cell adhesion by the knockdown of C-cadherin increased gap volume while leaving intracellular and interstitial pressures essentially unchanged. In both normal and adhesion-reduced ectoderm, cortical tension of the free cell surfaces at gaps does not return to the high values characteristic of the free surface of the whole tissue. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

A study of resonant-cavity and fiberglass-filled parallel baffles as duct silencers. [for wind tunnels

NASA Technical Reports Server (NTRS)

Soderman, P. T.

1982-01-01

Acoustical performance and pressure drop were measured for two types of splitters designed to attenuate sound propagating in ducts - resonant-cavity baffles and fiberglass-filled baffles. Arrays of four baffles were evaluated in the 7- by 10-foot wind tunnel number 1 at Ames Research Center at flow speeds from 0 to 41 m/sec. The baffles were 2.1 m high, 305 to 406 mm thick, and 3.1 to 4.4 m long. Emphasis was on measurements of silencer insertion loss as affected by variations of such parameters as baffle length, baffle thickness, perforated skin geometry, cavity size and shape, cavity damping, wind speed, and acoustic field directivity. An analytical method for predicting silencer performance is described and compared with measurements. With the addition of cavity damping in the form of 25-mm foam linings, the insertion loss above 250 Hz of the resonant-cavity baffles was improved 2 to 7 db compared with the undamped baffles; the loss became equal to or greater than the insertion loss of comparable size fiberglass baffles at frequencies above 250 Hz. Variations of cavity size and shape showed that a series of cavities with triangular cross-sections (i.e., variable depth) were superior to cavities with rectangular cross sections (i.e., constant depth). In wind, the undamped, resonant-cavity baffles generated loud cavity-resonance tones; the tones could be eliminated by cavity damping.

Concurrent natural and sexual selection in wild male sockeye salmon, Oncorhynchus nerka.

PubMed

Hamon, Troy R; Foote, Chris J

2005-05-01

Concurrent natural and sexual selection have been inferred from laboratory and comparative studies in a number of taxa, but are rarely measured in natural populations. Because the interaction of these two general categories of selection may be complex when they occur simultaneously, empirical evidence from natural populations would help us to understand this interaction and probably give us greater insight into each separate episode as well. In male sockeye salmon, sexual selection for larger body size has been indicated in both deep and shallow water habitats. However, in shallow habitats male sockeye are generally smaller and less deep-bodied than in deep habitats, a difference that has been ascribed to natural selection. We measured concurrent natural and sexual selection in two years on breeding male sockeye salmon with respect to body size, body shape, and time of arrival to the breeding grounds. Natural selection was variable in effect and sexual selection was variable in intensity in these two years. The patterns of selection also appear to be interdependent; areas where predation on spawning adults is not intense have yielded different patterns of sexual selection than those measured here. It appears that some of the body shape differences in sockeye salmon associated with different spawning habitats, which were previously attributed to selective mortality, may be a result of different patterns of sexual selection in the different habitats. Total selection resulting from the combination of both natural and sexual selection was less intense than either natural or sexual selection in most cases. Measurement of concurrent selection episodes in nature may help us to understand whether the pattern of differential sexual selection is common, and whether observed patterns of habitat-related differentiation may be due to differences in sexual selection.

Comparative study of dental anomalies assessed with panoramic radiographs of Down syndrome and non-Down syndrome patients.

PubMed

Mayoral-Trias, M A; Llopis-Perez, J; Puigdollers Pérez, A

2016-03-01

The aim of this study was to compare the prevalence of dental anomalies from panoramic radiographs of age-matched individuals with and without Down Syndrome (DS). This is a retrospective cross-sectional study. A group of 41 patients (19 female and 22 male) with Down Syndrome (DS), mean age 10.6 ± 1.4 and a control group of 42 non- DS patients (26 female and 16 male), mean age 11.1 ± 1.3 were studied. This study examined the medical history and a panoramic radiograph of each patient. The dental anomalies studied were agenesis of permanent teeth (except third molars), size and shape maxillary lateral anomalies and maxillary canine eruption path anomalies. The groups were compared using Mann-Whitney and Wilcoxon non-parametric tests (p<0.05). Rho Spearman correlation coefficient was applied for associations. Results Agenesis of one permanent tooth was found in 73.17% of DS subjects and two or more permanent teeth in more than 50% (p<0.001). Maxillary lateral incisor was the most frequently absent tooth followed by mandibular second premolar, mandibular lateral incisor, maxillary second premolar and mandibular central incisor. No significant differences were detected between maxilla and mandible on either side. No differences in gender were observed. Significant differences were found for size and shape anomalies of maxillary lateral incisors, as well as for canine eruption anomalies (p<0.05). No gender differences were observed for either variable. No association was found between these two variables in the DS group. More dental anomalies were present in the DS group than in the control group, which implied that DS patients need periodical dental and orthodontic supervision so as to prevent or control subsequent oral problems.

Sperm motility parameters and spermatozoa morphometric characterization in marine species: a study of swimmer and sessile species.

PubMed

Gallego, V; Pérez, L; Asturiano, J F; Yoshida, M

2014-09-15

The biodiversity of marine ecosystems is diverse and a high number of species coexist side by side. However, despite the fact that most of these species share a common fertilization strategy, a high variability in terms of the size, shape, and motion of spermatozoa can be found. In this study, we have analyzed both the sperm motion parameters and the spermatozoa morphometric features of two swimmer (pufferfish and European eel) and two sessile (sea urchin and ascidian) marine species. The most important differences in the sperm motion parameters were registered in the swimming period. Sessile species sperm displayed notably higher values than swimmer species sperm. In addition, the sperm motilities and velocities of the swimmer species decreased sharply once the sperm was activated, whereas the sessile species were able to maintain their initial values for a long time. These results are linked directly to the species-specific lifestyles. Although sessile organisms, which show limited or no movement, need sperm with a capacity to swim for long distances to find the oocytes, swimmer organisms can move toward the female and release gametes near it, and therefore the spermatozoa does not need to swim for such a long time. At the same time, sperm morphology is related to sperm motion parameters, and in this study an in-depth morphometric analysis of ascidian, sea urchin, and pufferfish spermatozoa, using computer-assisted sperm analysis software, has been carried out for the first time. A huge variability in shapes, sizes, and structures of the studied species was found using electron microscopy. Copyright © 2014 Elsevier Inc. All rights reserved.

Contrasting habitat associations of imperilled endemic stream fishes from a global biodiversity hot spot

PubMed Central

2012-01-01

Background Knowledge of the factors that drive species distributions provides a fundamental baseline for several areas of research including biogeography, phylogeography and biodiversity conservation. Data from 148 minimally disturbed sites across a large drainage system in the Cape Floristic Region of South Africa were used to test the hypothesis that stream fishes have similar responses to environmental determinants of species distribution. Two complementary statistical approaches, boosted regression trees and hierarchical partitioning, were used to model the responses of four fish species to 11 environmental predictors, and to quantify the independent explanatory power of each predictor. Results Elevation, slope, stream size, depth and water temperature were identified by both approaches as the most important causal factors for the spatial distribution of the fishes. However, the species showed marked differences in their responses to these environmental variables. Elevation and slope were of primary importance for the laterally compressed Sandelia spp. which had an upstream boundary below 430 m above sea level. The fusiform shaped Pseudobarbus ‘Breede’ was strongly influenced by stream width and water temperature. The small anguilliform shaped Galaxias ‘nebula’ was more sensitive to stream size and depth, and also penetrated into reaches at higher elevation than Sandelia spp. and Pseudobarbus ‘Breede’. Conclusions The hypothesis that stream fishes have a common response to environmental descriptors is rejected. The contrasting habitat associations of stream fishes considered in this study could be a reflection of their morphological divergence which may allow them to exploit specific habitats that differ in their environmental stressors. Findings of this study encourage wider application of complementary methods in ecological studies, as they provide more confidence and deeper insights into the variables that should be managed to achieve desired conservation outcomes. PMID:23009367

A Variable Resolution Atmospheric General Circulation Model for a Megasite at the North Slope of Alaska

NASA Astrophysics Data System (ADS)

Dennis, L.; Roesler, E. L.; Guba, O.; Hillman, B. R.; McChesney, M.

2016-12-01

The Atmospheric Radiation Measurement (ARM) climate research facility has three siteslocated on the North Slope of Alaska (NSA): Barrrow, Oliktok, and Atqasuk. These sites, incombination with one other at Toolik Lake, have the potential to become a "megasite" whichwould combine observational data and high resolution modeling to produce high resolutiondata products for the climate community. Such a data product requires high resolutionmodeling over the area of the megasite. We present three variable resolution atmosphericgeneral circulation model (AGCM) configurations as potential alternatives to stand-alonehigh-resolution regional models. Each configuration is based on a global cubed-sphere gridwith effective resolution of 1 degree, with a refinement in resolution down to 1/8 degree overan area surrounding the ARM megasite. The three grids vary in the size of the refined areawith 13k, 9k, and 7k elements. SquadGen, NCL, and GIMP are used to create the grids.Grids vary based upon the selection of areas of refinement which capture climate andweather processes that may affect a proposed NSA megasite. A smaller area of highresolution may not fully resolve climate and weather processes before they reach the NSA,however grids with smaller areas of refinement have a significantly reduced computationalcost compared with grids with larger areas of refinement. Optimal size and shape of thearea of refinement for a variable resolution model at the NSA is investigated.

Genetic variability and phenotypic plasticity of metric thoracic traits in an invasive drosophilid in America.

PubMed

Bitner-Mathé, Blanche Christine; David, Jean Robert

2015-08-01

Thermal phenotypic plasticity of 5 metric thoracic traits (3 related to size and 2 to pigmentation) was investigated in Zaprionus indianus with an isofemale line design. Three of these traits are investigated for the first time in a drosophilid, i.e. thorax width and width of pigmented longitudinal white and black stripes. The reaction norms of white and black stripes were completely different: white stripes were insensitive to growth temperature while the black stripes exhibited a strong linear decrease with increasing temperatures. Thorax width exhibited a concave reaction norm, analogous but not identical to those of wing length and thorax length: the temperatures of maximum value were different, the highest being for thorax width. All traits exhibited a significant heritable variability and a low evolvability. Sexual dimorphism was very variable among traits, being nil for white stripes and thorax width, and around 1.13 for black stripes. The ratio thorax length to thorax width (an elongation index) was always >1, showing that males have a more rounded thorax at all temperatures. Black stripes revealed a significant increase of sexual dimorphism with increasing temperature. Shape indices, i.e. ratios between size traits all exhibited a linear decrease with temperature, the least sensitive being the elongation index. All these results illustrate the complexity of developmental processes but also the analytical strength of biometrical plasticity studies in an eco-devo perspective.

Clarification of effects of DDE on shell thickness, size, mass, and shape of avian eggs

USGS Publications Warehouse

Blus, Lawrence J.; Wiemeyer, Stanley N.; Bunck, Christine M.

1997-01-01

Moriarty et al. (1986) used field data to conclude that DDE decreased the size or altered the shape of avian eggs; therefore, they postulated that decreased eggshell thickness was a secondary effect because, as a general rule, thickness and egg size are positively correlated. To further test this relationship, the present authors analyzed data from eggs of captive American kestrels. Falco sparverius given DDT- or DDE-contaminated or clean diets and from wild brown pelicans Pelecanus occidentalis collected both before (pre-1946) and after (post-1945) DDT was introduced into the environment. Pertinent data from other field and laboratory studies were also summarized. DDE was not related to and did not affect size, mass, or shape of eggs of the brown pelican or American kestrel; but the relationship of DDE to eggshell thinning held true. Size and shape of eggs of brown pelicans from the post-1945 era and those of kestrels, on DDT-contaminated diets showed some significant, but inconsistent, changes compared to brown pelican data from the pre-1946 era or kestrels on clean diets. In contrast, nearly all samples of eggs of experimental kestrels given DDT-contaminated diets and those of wild brown pelicans from the post-1945 era exhibited significant eggshell thinning. Pertinent experimental studies with other sensitive avian species indicated no effects of DDE on the size or shape of eggs, even though the high dietary concentrations caused extreme eggshell thinning and mortality of some adult mallards (Anas platyrhynchos) in one study. These findings essentially controvert the argument that decreased eggshell thickness is a secondary effect resulting from the primary effect of DDE-induced changes in the size or shape of eggs.

ICP-MS analysis of lanthanide-doped nanoparticles as a non-radiative, multiplex approach to quantify biodistribution and blood clearance.

PubMed

Crayton, Samuel H; Elias, Drew R; Al Zaki, Ajlan; Cheng, Zhiliang; Tsourkas, Andrew

2012-02-01

Recent advances in material science and chemistry have led to the development of nanoparticles with diverse physicochemical properties, e.g. size, charge, shape, and surface chemistry. Evaluating which physicochemical properties are best for imaging and therapeutic studies is challenging not only because of the multitude of samples to evaluate, but also because of the large experimental variability associated with in vivo studies (e.g. differences in tumor size, injected dose, subject weight, etc.). To address this issue, we have developed a lanthanide-doped nanoparticle system and analytical method that allows for the quantitative comparison of multiple nanoparticle compositions simultaneously. Specifically, superparamagnetic iron oxide (SPIO) with a range of different sizes and charges were synthesized, each with a unique lanthanide dopant. Following the simultaneous injection of the various SPIO compositions into tumor-bearing mice, inductively coupled plasma mass spectroscopy (ICP-MS) was used to quantitatively and orthogonally assess the concentration of each SPIO composition in serial blood samples and the resected tumor and organs. The method proved generalizable to other nanoparticle platforms, including dendrimers, liposomes, and polymersomes. This approach provides a simple, cost-effective, and non-radiative method to quantitatively compare tumor localization, biodistribution, and blood clearance of more than 10 nanoparticle compositions simultaneously, removing subject-to-subject variability. Copyright © 2011 Elsevier Ltd. All rights reserved.

Controllable synthesis of Co3O4 nanocrystals as efficient catalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Li, Baoying; Zhang, Yihe; Du, Ruifeng; Liu, Lei; Yu, Xuelian

2018-03-01

The electrochemical oxygen reduction reaction (ORR) has received great attention due to its importance in fuel cells and metal-air batteries. Here, we present a simple approach to prepare non-noble metal catalyst-Co3O4 nanocrystals (NCs). The particle size and shape were simply controlled by different types and concentrations of metal precursor. Furthermore, different sizes and shapes of Co3O4 NCs are explored as electrocatalysts for ORR, and it has been observed that particles with a similar shape, and smaller particle size led to greater catalytic current densities because of the greater surface area. For particles with a comparable size, the shape or crystalline structure governed the activity of the electrocatalytic reactions. Most importantly, the 9 nm-Co3O4 were demonstrated to act as low-cost catalysts for the ORR with a similar performance to that of Pt catalysts.

A Marked Poisson Process Driven Latent Shape Model for 3D Segmentation of Reflectance Confocal Microscopy Image Stacks of Human Skin.

PubMed

Ghanta, Sindhu; Jordan, Michael I; Kose, Kivanc; Brooks, Dana H; Rajadhyaksha, Milind; Dy, Jennifer G

2017-01-01

Segmenting objects of interest from 3D data sets is a common problem encountered in biological data. Small field of view and intrinsic biological variability combined with optically subtle changes of intensity, resolution, and low contrast in images make the task of segmentation difficult, especially for microscopy of unstained living or freshly excised thick tissues. Incorporating shape information in addition to the appearance of the object of interest can often help improve segmentation performance. However, the shapes of objects in tissue can be highly variable and design of a flexible shape model that encompasses these variations is challenging. To address such complex segmentation problems, we propose a unified probabilistic framework that can incorporate the uncertainty associated with complex shapes, variable appearance, and unknown locations. The driving application that inspired the development of this framework is a biologically important segmentation problem: the task of automatically detecting and segmenting the dermal-epidermal junction (DEJ) in 3D reflectance confocal microscopy (RCM) images of human skin. RCM imaging allows noninvasive observation of cellular, nuclear, and morphological detail. The DEJ is an important morphological feature as it is where disorder, disease, and cancer usually start. Detecting the DEJ is challenging, because it is a 2D surface in a 3D volume which has strong but highly variable number of irregularly spaced and variably shaped "peaks and valleys." In addition, RCM imaging resolution, contrast, and intensity vary with depth. Thus, a prior model needs to incorporate the intrinsic structure while allowing variability in essentially all its parameters. We propose a model which can incorporate objects of interest with complex shapes and variable appearance in an unsupervised setting by utilizing domain knowledge to build appropriate priors of the model. Our novel strategy to model this structure combines a spatial Poisson process with shape priors and performs inference using Gibbs sampling. Experimental results show that the proposed unsupervised model is able to automatically detect the DEJ with physiologically relevant accuracy in the range 10- 20 μm .

A Marked Poisson Process Driven Latent Shape Model for 3D Segmentation of Reflectance Confocal Microscopy Image Stacks of Human Skin

PubMed Central

Ghanta, Sindhu; Jordan, Michael I.; Kose, Kivanc; Brooks, Dana H.; Rajadhyaksha, Milind; Dy, Jennifer G.

2016-01-01

Segmenting objects of interest from 3D datasets is a common problem encountered in biological data. Small field of view and intrinsic biological variability combined with optically subtle changes of intensity, resolution and low contrast in images make the task of segmentation difficult, especially for microscopy of unstained living or freshly excised thick tissues. Incorporating shape information in addition to the appearance of the object of interest can often help improve segmentation performance. However, shapes of objects in tissue can be highly variable and design of a flexible shape model that encompasses these variations is challenging. To address such complex segmentation problems, we propose a unified probabilistic framework that can incorporate the uncertainty associated with complex shapes, variable appearance and unknown locations. The driving application which inspired the development of this framework is a biologically important segmentation problem: the task of automatically detecting and segmenting the dermal-epidermal junction (DEJ) in 3D reflectance confocal microscopy (RCM) images of human skin. RCM imaging allows noninvasive observation of cellular, nuclear and morphological detail. The DEJ is an important morphological feature as it is where disorder, disease and cancer usually start. Detecting the DEJ is challenging because it is a 2D surface in a 3D volume which has strong but highly variable number of irregularly spaced and variably shaped “peaks and valleys”. In addition, RCM imaging resolution, contrast and intensity vary with depth. Thus a prior model needs to incorporate the intrinsic structure while allowing variability in essentially all its parameters. We propose a model which can incorporate objects of interest with complex shapes and variable appearance in an unsupervised setting by utilizing domain knowledge to build appropriate priors of the model. Our novel strategy to model this structure combines a spatial Poisson process with shape priors and performs inference using Gibbs sampling. Experimental results show that the proposed unsupervised model is able to automatically detect the DEJ with physiologically relevant accuracy in the range 10 – 20µm. PMID:27723590

Low Dimensional Non-Crystallographic Metallic Nanostructures:. HRTEM Simulation, Models and Experimental Results

NASA Astrophysics Data System (ADS)

Rodríguez-López, J. L.; Montejano-Carrizales, J. M.; José-Yacamán, M.

Modern nanoparticle research in the field of small metallic systems has confirmed that many nanoparticles take on some Platonic and Archimedean solids related shapes. A Platonic solid looks the same from any vertex, and intuitively they appear as good candidates for atomic equilibrium shapes. A very clear example is the icosahedral (Ih) particle that only shows {111} faces that contribute to produce a more rounded structure. Indeed, many studies report the Ih as the most stable particle at the size range r≤20 Å for noble gases and for some metals. In this review, we report on the structure and shape of mono- and bimetallic nanoparticles in the wide size range from 1-300 nm. First, we present AuPd nanoparticles in the 1-2 nm size range that show dodecahedral atomic growth packing, one of the Platonic solid shapes that have not been identified before in this small size range for metallic particles. Next, with particles in the size range of 2-5 nm, we present an energetic surface reconstruction phenomenon observed also on bimetallic nanoparticle systems of AuPd and AuCu, similar to a re-solidification effect observed during cooling process in lead clusters. These binary alloy nanoparticles show the fivefold edges truncated, resulting in {100} faces on decahedral structures, an effect largely envisioned and reported theoretically, with no experimental evidence in the literature before. Next nanostructure we review is a monometallic system in the size range of ≈5 nm that we termed the decmon. We present here some detailed geometrical analysis and experimental evidence that supports our models. Finally, in the size range of 100-300 nm, we present icosahedrally derived star gold nanocrystals which resembles the great stellated dodechaedron, which is a Kepler-Poisont solid. We conclude then that the shape or morphology of some mono- and bimetallic particles evolves with size following the sequence from atoms to the Platonic solids, and with a slightly greater particle's size, they tend to adopt Archimedean related shapes. If the particle's size is still greater, they tend to adopt shapes beyond the Archimedean (Kepler-Poisont) solids, reaching at the very end the bulk structure of solids. We demonstrate both experimentally and by means of computational simulations for each case that this structural atomic growth sequence is followed in such mono- and bimetallic nanoparticles.

Towards climatological study on the characteristics of aerosols in Central Africa and Mediterranean sites

NASA Astrophysics Data System (ADS)

Benkhalifa, Jamel; Chaabane, Mabrouk

2016-02-01

The atmosphere contains molecules, clouds and aerosols that are sub-millimeter particles having a large variability in size, shape, chemical composition, lifetime and contents. The aerosols concentration depends greatly on the geographical situation, meteorological and environmental conditions, which makes aerosol climatology difficult to assess. Setting up a solar photometer (automatic, autonomous and portable instrument) on a given site allows carrying out the necessary measurements for aerosol characterization. The particle microphysical and optical properties are obtained from photometric measurements. The objective of this study is to analyze the spatial variability of aerosol optical thickness (AOT) in several Mediterranean regions and Central Africa, we considered a set of simultaneous data in the AErosol RObotic NETwork (AERONET) from six sites, two of which are located in Central Africa (Banizoumbou and Zinder Airport) and the rest are Mediterranean sites (Barcelona, Malaga, Lampedusa, and Forth Crete). The results have shown that the physical properties of aerosols are closely linked to the climate nature of the studied site. The optical thickness, single scattering albedo and aerosols size distribution can be due to the aging of the dust aerosol as they are transported over the Mediterranean basin.

An issue encountered in solving problems in electricity and magnetism: curvilinear coordinates

NASA Astrophysics Data System (ADS)

Gülçiçek, Çağlar; Damlı, Volkan

2016-11-01

In physics lectures on electromagnetic theory and mathematical methods, physics teacher candidates have some difficulties with curvilinear coordinate systems. According to our experience, based on both in-class interactions and teacher candidates’ answers in test papers, they do not seem to have understood the variables in curvilinear coordinate systems very well. For this reason, the problems that physics teacher candidates have with variables in curvilinear coordinate systems have been selected as a study subject. The aim of this study is to find the physics teacher candidates’ problems with determining the variables of drawn shapes, and problems with drawing shapes based on given variables in curvilinear coordinate systems. Two different assessment tests were used in the study to achieve this aim. The curvilinear coordinates drawing test (CCDrT) was used to discover their problems related to drawing shapes, and the curvilinear coordinates detection test (CCDeT) was used to find out about problems related to determining variables. According to the findings obtained from both tests, most physics teacher candidates have problems with the ϕ variable, while they have limited problems with the r variable. Questions that are mostly answered wrongly have some common properties, such as value. According to inferential statistics, there is no significant difference between the means of the CCDeT and CCDrT scores. The mean of the CCDeT scores is only 4.63 and the mean of the CCDrT is only 4.66. Briefly, we can say that most physics teacher candidates have problems with drawing a shape using the variables of curvilinear coordinate systems or in determining the variables of drawn shapes. Part of this study was presented at the XI. National Science and Mathematics Education Congress (UFBMEK) in 2014.

Shape-memory polymer foam device for treating aneurysms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortega, Jason M.; Benett, William J.; Small, Ward

A system for treating an aneurysm in a blood vessel or vein, wherein the aneurysm has a dome, an interior, and a neck. The system includes a shape memory polymer foam in the interior of the aneurysm between the dome and the neck. The shape memory polymer foam has pores that include a first multiplicity of pores having a first pore size and a second multiplicity of pores having a second pore size. The second pore size is larger than said first pore size. The first multiplicity of pores are located in the neck of the aneurysm. The second multiplicitymore » of pores are located in the dome of the aneurysm.« less

The effects of dielectric decrement and finite ion size on differential capacitance of electrolytically gated graphene

NASA Astrophysics Data System (ADS)

Daniels, Lindsey; Scott, Matthew; Mišković, Z. L.

2018-06-01

We analyze the effects of dielectric decrement and finite ion size in an aqueous electrolyte on the capacitance of a graphene electrode, and make comparisons with the effects of dielectric saturation combined with finite ion size. We first derive conditions for the cross-over from a camel-shaped to a bell-shaped capacitance of the diffuse layer. We show next that the total capacitance is dominated by a V-shaped quantum capacitance of graphene at low potentials. A broad peak develops in the total capacitance at high potentials, which is sensitive to the ion size with dielectric saturation, but is stable with dielectric decrement.

Forces and dynamics in epithelial domes of controlled size and shape

NASA Astrophysics Data System (ADS)

Latorre-Ibars, Ernest; Casares, Laura; Gomez-Gonzalez, Manuel; Uroz, Marina; Arroyo, Marino; Trepat, Xavier

Mechanobiology of epithelia plays a central role in morphogenesis, wound healing, and tumor progression. Its current understanding relies on mechanical measurements on flat epithelial layers. However, most epithelia in vivo exhibit a curved 3D shape enclosing a pressurized lumen. Using soft micropatterned substrates we produce massive parallel arrays of epithelial domes with controlled size and basal shape. We measure epithelial traction, tension, and luminal pressure in epithelial domes. The local stress tensor on the freestanding epithelial membrane is then mapped by combining measured luminal pressure and local curvature. We show that tension and cell shape are highly anisotropic and vary along the meridional position of the domes. Finally, we establish constitutive relations between shape, tension, and pressure during perturbations of the contractile machinery, osmotic shocks, and spontaneous fluctuations of dome volume. Our findings contradict a description of the epithelium as a fluid capillary surface. Cells in the dome are unable to relax into a uniform and isotropic tensional state through sub- and supra-cellular rearrangements. Mapping epithelial shape, tension, and pressure will enable quantitative studies of mechanobiology in 3D epithelia of controlled size and shape.

Solar granulation and statistical crystallography: A modeling approach using size-shape relations

NASA Technical Reports Server (NTRS)

Noever, D. A.

1994-01-01

The irregular polygonal pattern of solar granulation is analyzed for size-shape relations using statistical crystallography. In contrast to previous work which has assumed perfectly hexagonal patterns for granulation, more realistic accounting of cell (granule) shapes reveals a broader basis for quantitative analysis. Several features emerge as noteworthy: (1) a linear correlation between number of cell-sides and neighboring shapes (called Aboav-Weaire's law); (2) a linear correlation between both average cell area and perimeter and the number of cell-sides (called Lewis's law and a perimeter law, respectively) and (3) a linear correlation between cell area and squared perimeter (called convolution index). This statistical picture of granulation is consistent with a finding of no correlation in cell shapes beyond nearest neighbors. A comparative calculation between existing model predictions taken from luminosity data and the present analysis shows substantial agreements for cell-size distributions. A model for understanding grain lifetimes is proposed which links convective times to cell shape using crystallographic results.

Gold nanoparticle size and shape influence on osteogenesis of mesenchymal stem cells

NASA Astrophysics Data System (ADS)

Li, Jingchao; Li, Jia'en Jasmine; Zhang, Jing; Wang, Xinlong; Kawazoe, Naoki; Chen, Guoping

2016-04-01

Gold nanoparticles (AuNPs) have been extensively explored for biomedical applications due to their advantages of facile synthesis and surface functionalization. Previous studies have suggested that AuNPs can induce differentiation of stem cells into osteoblasts. However, how the size and shape of AuNPs affect the differentiation response of stem cells has not been elucidated. In this work, a series of bovine serum albumin (BSA)-coated Au nanospheres, Au nanostars and Au nanorods with different diameters of 40, 70 and 110 nm were synthesized and their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) were investigated. All the AuNPs showed good cytocompatibility and did not influence proliferation of hMSCs at the studied concentrations. Osteogenic differentiation of hMSCs was dependent on the size and shape of AuNPs. Sphere-40, sphere-70 and rod-70 significantly increased the alkaline phosphatase (ALP) activity and calcium deposition of cells while rod-40 reduced the ALP activity and calcium deposition. Gene profiling revealed that the expression of osteogenic marker genes was down-regulated after incubation with rod-40. However, up-regulation of these genes was found in the sphere-40, sphere-70 and rod-70 treatment. Moreover, it was found that the size and shape of AuNPs affected the osteogenic differentiation of hMSCs through regulating the activation of Yes-associated protein (YAP). These results indicate that the size and shape of AuNPs had an influence on the osteogenic differentiation of hMSCs, which should provide useful guidance for the preparation of AuNPs with defined size and shape for their biomedical applications.Gold nanoparticles (AuNPs) have been extensively explored for biomedical applications due to their advantages of facile synthesis and surface functionalization. Previous studies have suggested that AuNPs can induce differentiation of stem cells into osteoblasts. However, how the size and shape of AuNPs affect the differentiation response of stem cells has not been elucidated. In this work, a series of bovine serum albumin (BSA)-coated Au nanospheres, Au nanostars and Au nanorods with different diameters of 40, 70 and 110 nm were synthesized and their effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) were investigated. All the AuNPs showed good cytocompatibility and did not influence proliferation of hMSCs at the studied concentrations. Osteogenic differentiation of hMSCs was dependent on the size and shape of AuNPs. Sphere-40, sphere-70 and rod-70 significantly increased the alkaline phosphatase (ALP) activity and calcium deposition of cells while rod-40 reduced the ALP activity and calcium deposition. Gene profiling revealed that the expression of osteogenic marker genes was down-regulated after incubation with rod-40. However, up-regulation of these genes was found in the sphere-40, sphere-70 and rod-70 treatment. Moreover, it was found that the size and shape of AuNPs affected the osteogenic differentiation of hMSCs through regulating the activation of Yes-associated protein (YAP). These results indicate that the size and shape of AuNPs had an influence on the osteogenic differentiation of hMSCs, which should provide useful guidance for the preparation of AuNPs with defined size and shape for their biomedical applications. Electronic supplementary information (ESI) available: Additional experimental results. See DOI: 10.1039/c5nr08808a

Liquid-Liquid Phase Separation in a Dual Variable Domain Immunoglobulin Protein Solution: Effect of Formulation Factors and Protein-Protein Interactions.

PubMed

Raut, Ashlesha S; Kalonia, Devendra S

2015-09-08

Dual variable domain immunoglobulin proteins (DVD-Ig proteins) are large molecules (MW ∼ 200 kDa) with increased asymmetry because of their extended Y-like shape, which results in increased formulation challenges. Liquid-liquid phase separation (LLPS) of protein solutions into protein-rich and protein-poor phases reduces solution stability at intermediate concentrations and lower temperatures, and is a serious concern in formulation development as therapeutic proteins are generally stored at refrigerated conditions. In the current work, LLPS was studied for a DVD-Ig protein molecule as a function of solution conditions by measuring solution opalescence. LLPS of the protein was confirmed by equilibrium studies and by visually observing under microscope. The protein does not undergo any structural change after phase separation. Protein-protein interactions were measured by light scattering (kD) and Tcloud (temperature that marks the onset of phase separation). There is a good agreement between kD measured in dilute solution with Tcloud measured in the critical concentration range. Results indicate that the increased complexity of the molecule (with respect to size, shape, and charge distribution on the molecule) increases contribution of specific and nonspecific interactions in solution, which are affected by formulation factors, resulting in LLPS for DVD-Ig protein.

The study of craniofacial growth patterns using 3D laser scanning and geometric morphometrics

NASA Astrophysics Data System (ADS)

Friess, Martin

2006-02-01

Throughout childhood, braincase and face grow at different rates and therefore exhibit variable proportions and positions relative to each other. Our understanding of the direction and magnitude of these growth patterns is crucial for many ergonomic applications and can be improved by advanced 3D morphometrics. The purpose of this study is to investigate this known growth allometry using 3D imaging techniques. The geometry of the head and face of 840 children, aged 2 to 19, was captured with a laser surface scanner and analyzed statistically. From each scan, 18 landmarks were extracted and registered using General Procrustes Analysis (GPA). GPA eliminates unwanted variation due to position, orientation and scale by applying a least-squares superimposition algorithm to individual landmark configurations. This approach provides the necessary normalization for the study of differences in size, shape, and their interaction (allometry). The results show that throughout adolescence, boys and girls follow a different growth trajectory, leading to marked differences not only in size but also in shape, most notably in relative proportions of the braincase. These differences can be observed during early childhood, but become most noticeable after the age of 13 years, when craniofacial growth in girls slows down significantly, whereas growth in boys continues for at least 3 more years.

Size and shape-dependent cytotoxicity profile of gold nanoparticles for biomedical applications.

PubMed

Woźniak, Anna; Malankowska, Anna; Nowaczyk, Grzegorz; Grześkowiak, Bartosz F; Tuśnio, Karol; Słomski, Ryszard; Zaleska-Medynska, Adriana; Jurga, Stefan

2017-06-01

Metallic nanoparticles, in particular gold nanoparticles (AuNPs), offer a wide spectrum of applications in biomedicine. A crucial issue is their cytotoxicity, which depends greatly on various factors, including morphology of nanoparticles. Because metallic nanoparticles have an effect on cell membrane integrity, their shape and size may affect the viability of cells, due to their different geometries as well as physical and chemical interactions with cell membranes. Variations in the size and shape of gold nanoparticles may indicate particular nanoparticle morphologies that provide strong cytotoxicity effects. Synthesis of different sized and shaped bare AuNPs was performed with spherical (~ 10 nm), nanoflowers (~ 370 nm), nanorods (~ 41 nm), nanoprisms (~ 160 nm) and nanostars (~ 240 nm) morphologies. These nanostructures were characterized and interacting with cancer (HeLa) and normal (HEK293T) cell lines and cell viability tests were performed by WST-1 tests and fluorescent live/dead cell imaging experiments. It was shown that various shapes and sizes of gold nanostructures may affect the viability of the cells. Gold nanospheres and nanorods proved to be more toxic than star, flower and prism gold nanostructures. This may be attributed to their small size and aggregation process. This is the first report concerning a comparison of cytotoxic profile in vitro with a wide spectrum of bare AuNPs morphology. The findings show their possible use in biomedical applications.

Why do shape aftereffects increase with eccentricity?

PubMed

Gheorghiu, Elena; Kingdom, Frederick A A; Bell, Jason; Gurnsey, Rick

2011-12-20

Studies have shown that spatial aftereffects increase with eccentricity. Here, we demonstrate that the shape-frequency and shape-amplitude aftereffects, which describe the perceived shifts in the shape of a sinusoidal-shaped contour following adaptation to a slightly different sinusoidal-shaped contour, also increase with eccentricity. Why does this happen? We first demonstrate that the perceptual shift increases with eccentricity for stimuli of fixed sizes. These shifts are not attenuated by variations in stimulus size; in fact, at each eccentricity the degree of perceptual shift is scale-independent. This scale independence is specific to the aftereffect because basic discrimination thresholds (in the absence of adaptation) decrease as size increases. Structural aspects of the displays were found to have a modest effect on the degree of perceptual shift; the degree of adaptation depends modestly on distance between stimuli during adaptation and post-adaptation testing. There were similar temporal rates of decline of adaptation across the visual field and higher post-adaptation discrimination thresholds in the periphery than in the center. The observed results are consistent with greater sensitivity reduction in adapted mechanisms following adaptation in the periphery or an eccentricity-dependent increase in the bandwidth of the shape-frequency- and shape-amplitude-selective mechanisms.

Growth trajectories in the cave bear and its extant relatives: an examination of ontogenetic patterns in phylogeny.

PubMed

Fuchs, Manuela; Geiger, Madeleine; Stange, Madlen; Sánchez-Villagra, Marcelo R

2015-11-02

The study of postnatal ontogeny can provide insights into evolution by offering an understanding of how growth trajectories have evolved resulting in adult morphological disparity. The Ursus lineage is a good subject for studying cranial and mandibular shape and size variation in relation to postnatal ontogeny and phylogeny because it is at the same time not diverse but the species exhibit different feeding ecologies. Cranial and mandibular shapes of Ursus arctos (brown bear), U. maritimus (polar bear), U. americanus (American black bear), and the extinct U. spelaeus (cave bear) were examined, using a three-dimensional geometric morphometric approach. Additionally, ontogenetic series of crania and mandibles of U. arctos and U. spelaeus ranging from newborns to senile age were sampled. The distribution of specimens in morphospace allowed to distinguish species and age classes and the ontogenetic trajectories U. arctos and U. spelaeus were found to be more similar than expected by chance. Cranial shape changes during ontogeny are largely size related whereas the evolution of cranial shape disparity in this clade appears to be more influenced by dietary adaptation than by size and phylogeny. The different feeding ecologies are reflected in different cranial and mandibular shapes among species. The cranial and mandibular shape disparity in the Ursus lineage appears to be more influenced by adaptation to diet than by size or phylogeny. In contrast, the cranial and mandibular shape changes during postnatal ontogeny in U. arctos and U. spelaeus are probably largely size related. The patterns of morphospace occupation of the cranium and the mandible in adults and through ontogeny are different.

Global statistics of microphysical properties of cloud-top ice crystals

NASA Astrophysics Data System (ADS)

van Diedenhoven, B.; Fridlind, A. M.; Cairns, B.; Ackerman, A. S.; Riedi, J.

2017-12-01

Ice crystals in clouds are highly complex. Their sizes, macroscale shape (i.e., habit), mesoscale shape (i.e., aspect ratio of components) and microscale shape (i.e., surface roughness) determine optical properties and affect physical properties such as fall speeds, growth rates and aggregation efficiency. Our current understanding on the formation and evolution of ice crystals under various conditions can be considered poor. Commonly, ice crystal size and shape are related to ambient temperature and humidity, but global observational statistics on the variation of ice crystal size and particularly shape have not been available. Here we show results of a project aiming to infer ice crystal size, shape and scattering properties from a combination of MODIS measurements and POLDER-PARASOL multi-angle polarimetry. The shape retrieval procedure infers the mean aspect ratios of components of ice crystals and the mean microscale surface roughness levels, which are quantifiable parameters that mostly affect the scattering properties, in contrast to "habit". We present global statistics on the variation of ice effective radius, component aspect ratio, microscale surface roughness and scattering asymmetry parameter as a function of cloud top temperature, latitude, location, cloud type, season, etc. Generally, with increasing height, sizes decrease, roughness increases, asymmetry parameters decrease and aspect ratios increase towards unity. Some systematic differences are observed for clouds warmer and colder than the homogeneous freezing level. Uncertainties in the retrievals will be discussed. These statistics can be used as observational targets for modeling efforts and to better constrain other satellite remote sensing applications and their uncertainties.

Improvement of Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size.

PubMed

Ma, Haotong; Liu, Zejin; Jiang, Pengzhi; Xu, Xiaojun; Du, Shaojun

2011-07-04

We propose and demonstrate the improvement of conventional Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size. Based on the detailed study of the refractive beam shaping system, we found that the conventional Galilean beam shaper can only work well for the magnifying beam shaping. Taking the transformation of input beam with Gaussian irradiance distribution into target beam with high order Fermi-Dirac flattop profile as an example, the shaper can only work well at the condition that the size of input and target beam meets R(0) ≥ 1.3 w(0). For the improvement, the shaper is regarded as the combination of magnifying and demagnifying beam shaping system. The surface and phase distributions of the improved Galilean beam shaping system are derived based on Geometric and Fourier Optics. By using the improved Galilean beam shaper, the accurate transformation of input beam with Gaussian irradiance distribution into target beam with flattop irradiance distribution is realized. The irradiance distribution of the output beam is coincident with that of the target beam and the corresponding phase distribution is maintained. The propagation performance of the output beam is greatly improved. Studies of the influences of beam size and beam order on the improved Galilean beam shaping system show that restriction of beam size has been greatly reduced. This improvement can also be used to redistribute the input beam with complicated irradiance distribution into output beam with complicated irradiance distribution.

Global Statistics of Microphysical Properties of Cloud-Top Ice Crystals

NASA Technical Reports Server (NTRS)

Van Diedenhoven, Bastiaan; Fridlind, Ann; Cairns, Brian; Ackerman, Andrew; Riedl, Jerome

2017-01-01

Ice crystals in clouds are highly complex. Their sizes, macroscale shape (i.e., habit), mesoscale shape (i.e., aspect ratio of components) and microscale shape (i.e., surface roughness) determine optical properties and affect physical properties such as fall speeds, growth rates and aggregation efficiency. Our current understanding on the formation and evolution of ice crystals under various conditions can be considered poor. Commonly, ice crystal size and shape are related to ambient temperature and humidity, but global observational statistics on the variation of ice crystal size and particularly shape have not been available. Here we show results of a project aiming to infer ice crystal size, shape and scattering properties from a combination of MODIS measurements and POLDER-PARASOL multi-angle polarimetry. The shape retrieval procedure infers the mean aspect ratios of components of ice crystals and the mean microscale surface roughness levels, which are quantifiable parameters that mostly affect the scattering properties, in contrast to a habit. We present global statistics on the variation of ice effective radius, component aspect ratio, microscale surface roughness and scattering asymmetry parameter as a function of cloud top temperature, latitude, location, cloud type, season, etc. Generally, with increasing height, sizes decrease, roughness increases, asymmetry parameters decrease and aspect ratios increase towards unity. Some systematic differences are observed for clouds warmer and colder than the homogeneous freezing level. Uncertainties in the retrievals will be discussed. These statistics can be used as observational targets for modeling efforts and to better constrain other satellite remote sensing applications and their uncertainties.

Size-dependent modification of asteroid family Yarkovsky V-shapes

NASA Astrophysics Data System (ADS)

Bolin, B. T.; Morbidelli, A.; Walsh, K. J.

2018-04-01

Context. The thermal properties of the surfaces of asteroids determine the magnitude of the drift rate cause by the Yarkovsky force. In the general case of Main Belt asteroids, the Yarkovsky force is indirectly proportional to the thermal inertia, Γ. Aim. Following the proposed relationship between Γ and asteroid diameter D, we find that asteroids' Yarkovsky drift rates might have a more complex size dependence than previous thought, leading to a curved family V-shape boundary in semi-major axis, a, vs. 1/D space. This implies that asteroids are drifting faster at larger sizes than previously considered decreasing on average the known ages of asteroid families. Methods: The V-Shape curvature is determined for >25 families located throughout the Main Belt to quantify the Yarkovsky size-dependent drift rate. Results: We find that there is no correlation between family age and V-shape curvature. In addition, the V-shape curvature decreases for asteroid families with larger heliocentric distances suggesting that the relationship between Γ and D is weaker in the outer MB possibly due to homogenous surface roughness among family members.

Highly rearranged and size-variable chloroplast genomes in conifers II clade (cupressophytes): evolution towards shorter intergenic spacers.

PubMed

Wu, Chung-Shien; Chaw, Shu-Miaw

2014-04-01

Although conifers are of immense ecological and economic value, bioengineering of their chloroplasts remains undeveloped. Understanding the chloroplast genomic organization of conifers can facilitate their bioengineering. Members of the conifer II clade (or cupressophytes) are highly diverse in both morphologic features and chloroplast genomic organization. We compared six cupressophyte chloroplast genomes (cpDNAs) that represent four of the five cupressophyte families, including three genomes that are first reported here (Agathis dammara, Calocedrus formosana and Nageia nagi). The six cupressophyte cpDNAs have lost a pair of large inverted repeats (IRs) and vary greatly in size, organization and tRNA copies. We demonstrate that cupressophyte cpDNAs have evolved towards reduced size, largely due to shrunken intergenic spacers. In cupressophytes, cpDNA rearrangements are capable of extending intergenic spacers, and synonymous mutations are negatively associated with the size and frequency of rearrangements. The variable cpDNA sizes of cupressophytes may have been shaped by mutational burden and genomic rearrangements. On the basis of cpDNA organization, our analyses revealed that in gymnosperms, cpDNA rearrangements are phylogenetically informative, which supports the 'gnepines' clade. In addition, removal of a specific IR influences the minimal rearrangements required for the gnepines and cupressophyte clades, whereby Pinaceae favours the removal of IRB but cupressophytes exclusion of IRA. This result strongly suggests that different IR copies have been lost from conifers I and II. Our data help understand the complexity and evolution of cupressophyte cpDNAs. © 2013 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology, The Association of Applied Biologists and John Wiley & Sons Ltd.

Birth dimensions in Melanesian and Indian Fijians and their relationships with maternal and socio-economic factors.

PubMed

Clegg, E J; Clegg, S D

1989-01-01

Fifty-nine Melanesian (MF) and 39 Indian (IF) Fijian full-term newborns were studied within 5 days of birth. Dimensions recorded included birthweight, length, crown-rump length, head circumference, upper limb length, bycondylar humeral and femoral diameters and four skinfolds (triceps, subscapular, suprailiac and thigh). Data from previous pregnancies of the presenting newborns' mothers were added to presenting birthweights, giving a total of 160 MF and 84 IF birthweights. In all birthweight and linear dimensions MFs were the bigger. Sex differences were significant in respect only of head circumference and the two bicondylar diameters. Multiple regression analysis showed dimensions in MF newborns to have few significant relationships with the maternal and socio-economic variables of age, parity, stature and years of education, but IFs had many more significant relationships. When covariance correction was made for the significant maternal and socio-economic variables (maternal age and parity) little effect on racial differences was seen. All linear dimensions except length could be subsumed into birthweight. MFs had greater triceps and subscapular skinfold thicknesses than IFs, a difference which was not much changed by covariance correction for significant maternal and socio-economic variables (maternal stature and years of education). Measurements of shape, expressed as ratios of linear dimensions, showed few racial differences but males had relatively broader limbs. For upper limb shape only, this difference was maintained after covariance correction for significant maternal and socio-economic variables (parity, stature and education). The greater size of MF infants at birth is associated with lower peri- and neonatal death rates. However this advantage is reversed during the remainder of the first year of life. It is suggested that better standards of infant care among IFs are responsible for this change.

Correlation between strength properties in standard test specimens and molded phenolic parts

NASA Technical Reports Server (NTRS)

Turner, P S; Thomason, R H

1946-01-01

This report describes an investigation of the tensile, flexural, and impact properties of 10 selected types of phenolic molding materials. The materials were studied to see in what ways and to what extent their properties satisfy some assumptions on which the theory of strength of materials is based: namely, (a) isotropy, (b) linear stress-strain relationship for small strains, and (c) homogeneity. The effect of changing the dimensions of tensile and flexural specimens and the span-depth ratio in flexural tests were studied. The strengths of molded boxes and flexural specimens cut from the boxes were compared with results of tests on standard test specimens molded from the respective materials. The nonuniformity of a material, which is indicated by the coefficient of variation, affects the results of tests made with specimens of different sizes and tests with different methods of loading. The strength values were found to depend on the relationship between size and shape of the molded specimen and size and shape of the fillers. The most significant variations observed within a diversified group of materials were found to depend on the orientation of fibrous fillers. Of secondary importance was the dependence of the variability of test results on the pieces of filler incorporated into the molding powder as well as on the size of the piece. Static breaking strength tests on boxes molded from six representative phenolic materials correlated well with falling-ball impact tests on specimens cut from molded flat sheets. Good correlation was obtained with Izod impact tests on standard test specimens prepared from the molding materials. The static breaking strengths of the boxes do not correlate with the results of tensile or flexural tests on standard specimens.

Do position and size matter? An analysis of cage and placement variables for optimum lordosis in PLIF reconstruction.

PubMed

Landham, Priyan R; Don, Angus S; Robertson, Peter A

2017-11-01

To examine monosegmental lordosis after posterior lumbar interbody fusion (PLIF) surgery and relate lordosis to cage size, shape, and placement. Eighty-three consecutive patients underwent single-level PLIF with paired identical lordotic cages involving a wide decompression and bilateral facetectomies. Cage parameters relating to size (height, lordosis, and length) and placement (expressed as a ratio relative to the length of the inferior vertebral endplate) were recorded. Centre point ratio (CPR) was the distance to the centre of both cages and indicated mean position of both cages. Posterior gap ratio (PGR) was the distance to the most posterior cage and indicated position and cage length indirectly. Relationships between lordosis and cage parameters were explored. Mean lordosis increased by 5.98° (SD 6.86°). The cages used varied in length from 20 to 27 mm, in lordosis from 10° to 18°, and in anterior cage height from 10 to 17 mm. The mean cage placement as determined by CPR was 0.54 and by PGR was 0.16. The significant correlations were: both CPR and PGR with lordosis gain at surgery (r = 0.597 and 0.537, respectively, p < 0.001 both), cage lordosis with the final lordosis (r = 0.234, p < 0.05), and anterior cage height was negatively correlated with a change in lordosis (r = -0.297, p < 0.01). Cage size, shape, and position, in addition to surgical technique, determine lordosis during PLIF surgery. Anterior placement with sufficient "clear space" behind the cages is recommended. In addition, cages should be of moderate height and length, so that they act as an effective pivot for lordosis.

Measuring the X-shaped structures in edge-on galaxies

NASA Astrophysics Data System (ADS)

Savchenko, S. S.; Sotnikova, N. Ya.; Mosenkov, A. V.; Reshetnikov, V. P.; Bizyaev, D. V.

2017-11-01

We present a detailed photometric study of a sample of 22 edge-on galaxies with clearly visible X-shaped structures. We propose a novel method to derive geometrical parameters of these features, along with the parameters of their host galaxies based on the multi-component photometric decomposition of galactic images. To include the X-shaped structure into our photometric model, we use the imfit package, in which we implement a new component describing the X-shaped structure. This method is applied for a sample of galaxies with available Sloan Digital Sky Survey and Spitzer IRAC 3.6 μm observations. In order to explain our results, we perform realistic N-body simulations of a Milky Way-type galaxy and compare the observed and the model X-shaped structures. Our main conclusions are as follows: (1) galaxies with strong X-shaped structures reside in approximately the same local environments as field galaxies; (2) the characteristic size of the X-shaped structures is about 2/3 of the bar size; (3) there is a correlation between the X-shaped structure size and its observed flatness: the larger structures are more flattened; (4) our N-body simulations qualitatively confirm the observational results and support the bar-driven scenario for the X-shaped structure formation.

Observations of Co-variation in Cloud Properties and their Relationships with Atmospheric State

NASA Astrophysics Data System (ADS)

Sinclair, K.; van Diedenhoven, B.; Fridlind, A. M.; Arnold, T. G.; Yorks, J. E.; Heymsfield, G. M.; McFarquhar, G. M.; Um, J.

2017-12-01

Radiative properties of upper tropospheric ice clouds are generally not well represented in global and cloud models. Cloud top height, cloud thermodynamic phase, cloud optical thickness, cloud water path, particle size and ice crystal shape all serve as observational targets for models to constrain cloud properties. Trends or biases in these cloud properties could have profound effects on the climate since they affect cloud radiative properties. Better understanding of co-variation between these cloud properties and linkages with atmospheric state variables can lead to better representation of clouds in models by reducing biases in their micro- and macro-physical properties as well as their radiative properties. This will also enhance our general understanding of cloud processes. In this analysis we look at remote sensing, in situ and reanalysis data from the MODIS Airborne Simulator (MAS), Cloud Physics Lidar (CPL), Cloud Radar System (CRS), GEOS-5 reanalysis data and GOES imagery obtained during the Tropical Composition, Cloud and Climate Coupling (TC4) airborne campaign. The MAS, CPL and CRS were mounted on the ER-2 high-altitude aircraft during this campaign. In situ observations of ice size and shape were made aboard the DC8 and WB57 aircrafts. We explore how thermodynamic phase, ice effective radius, particle shape and radar reflectivity vary with altitude and also investigate how these observed cloud properties vary with cloud type, cloud top temperature, relative humidity and wind profiles. Observed systematic relationships are supported by physical interpretations of cloud processes and any unexpected differences are examined.

Hemocytes of Rhipicephalus sanguineus (Acari: Ixodidae): Characterization, Population Abundance, and Ultrastructural Changes Following Challenge with Leishmania infantum.

PubMed

Feitosa, A P S; Alves, L C; Chaves, M M; Veras, D L; Silva, E M; Aliança, A S S; França, I R S; Gonçalves, G G A; Lima-Filho, J L; Brayner, F A

2015-11-01

Few studies have examined the cellular immune response of ticks, and further research on the characterization of the hemocytes of ticks is required, particularly on those of Rhipicephalus sanguineus (Latreille) because of the medical and veterinary importance of this tick. The aims of this study were to characterize the morphology and the ultrastructure of the different types of hemocytes of adult R. sanguineus and to determine the population abundance and the ultrastructural changes in the hemocytes of ticks infected with Leishmania infantum. The hemocytes were characterized through light and transmission electron microscopy. Within the variability of circulating cells in the hemolymph of adult R. sanguineus, five cell types were identified, which were the prohemocytes, plasmatocytes, granulocytes, spherulocytes, and adipohemocytes. The prohemocytes were the smallest cells found in the hemolymph. The plasmatocytes had polymorphic morphology with vesicles and cytoplasmic projections. The granulocytes had an elliptical shape with the cytoplasm filled with granules of different sizes and electrodensities. The spherulocytes were characterized by several spherules of uniform shapes and sizes that filled the entire cytoplasm, whereas the adipohemocytes had an irregular shape with multiple lipid inclusions that occupied almost the entire cytoplasmic space. The total counts of the hemocyte population increased in the group that was infected with L. infantum. Among the different cell types, the numbers increased and the ultrastructural changes occurred in the granulocytes and the plasmatocytes in the infected group of ticks. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Wing morphometrics of Aedes (Ochlerotatus) albifasciatus (Macquart, 1838) (Diptera: Culicidae) from different climatic regions of Argentina.

PubMed

Garzón, Maximiliano J; Schweigmann, Nicolás

2018-05-16

Gene flow restrictions between populations of Aedes albifasciatus, the vector of Western equine encephalitis and Dirophilaria immitis, have been described in the central region of Argentina. Genetic and eco-physiological variations usually result in local forms reflecting the climatic regions. Mosquito wings and their different parts have ecological functions in flight and communication. Therefore, wing shape could be considered an aspect of sexual dimorphism, and its eco-physiological responses can be expressed as morphological changes induced by the environment. To compare the geographical and sexual variations with respect to wing shape and size in two Ae. albifasciatus populations from contrasting climates of Argentina (temperate: Buenos Aires, and the arid steppe of Patagonia: Sarmiento), the wings of adults reared in thermal trays at different constant temperatures (10-29 °C) were analyzed. The wing size of Ae. albifasciatus showed inverse linear relationships with the rearing thermal condition and higher slope for Buenos Aires. In the cool range (10-17 °C), geographical size variations responded to the converse Bergmann's rule, where Buenos Aires individuals were larger than those from Sarmiento. Sexual shape dimorphism occurred in both populations while geographical variation in shape was observed in both sexes. Buenos Aires individuals showed greater response sensitivity with respect to the size-temperature relation than those from Sarmiento. The converse Bergmann's rule in size variation could be due to a higher development rate in Sarmiento to produce more cohorts in the limited favorable season. The shape could be more relevant with respect to the size in the study of population structures due to the size being more liable to vary due to changes in the environment. The geographical variations with respect to morphology could be favored by the isolation between populations and adaptations to the environmental conditions. Our results demonstrate that the shape and size of wing provide useful phenotypic information for studies related to sexual and environmental adaptations.

Landmark-free statistical analysis of the shape of plant leaves.

PubMed

Laga, Hamid; Kurtek, Sebastian; Srivastava, Anuj; Miklavcic, Stanley J

2014-12-21

The shapes of plant leaves are important features to biologists, as they can help in distinguishing plant species, measuring their health, analyzing their growth patterns, and understanding relations between various species. Most of the methods that have been developed in the past focus on comparing the shape of individual leaves using either descriptors or finite sets of landmarks. However, descriptor-based representations are not invertible and thus it is often hard to map descriptor variability into shape variability. On the other hand, landmark-based techniques require automatic detection and registration of the landmarks, which is very challenging in the case of plant leaves that exhibit high variability within and across species. In this paper, we propose a statistical model based on the Squared Root Velocity Function (SRVF) representation and the Riemannian elastic metric of Srivastava et al. (2011) to model the observed continuous variability in the shape of plant leaves. We treat plant species as random variables on a non-linear shape manifold and thus statistical summaries, such as means and covariances, can be computed. One can then study the principal modes of variations and characterize the observed shapes using probability density models, such as Gaussians or Mixture of Gaussians. We demonstrate the usage of such statistical model for (1) efficient classification of individual leaves, (2) the exploration of the space of plant leaf shapes, which is important in the study of population-specific variations, and (3) comparing entire plant species, which is fundamental to the study of evolutionary relationships in plants. Our approach does not require descriptors or landmarks but automatically solves for the optimal registration that aligns a pair of shapes. We evaluate the performance of the proposed framework on publicly available benchmarks such as the Flavia, the Swedish, and the ImageCLEF2011 plant leaf datasets. Copyright © 2014 Elsevier Ltd. All rights reserved.

SU-G-IeP3-08: Image Reconstruction for Scanning Imaging System Based On Shape-Modulated Point Spreading Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ruixing; Yang, LV; Xu, Kele

Purpose: Deconvolution is a widely used tool in the field of image reconstruction algorithm when the linear imaging system has been blurred by the imperfect system transfer function. However, due to the nature of Gaussian-liked distribution for point spread function (PSF), the components with coherent high frequency in the image are hard to restored in most of the previous scanning imaging system, even the relatively accurate PSF is acquired. We propose a novel method for deconvolution of images which are obtained by using shape-modulated PSF. Methods: We use two different types of PSF - Gaussian shape and donut shape -more » to convolute the original image in order to simulate the process of scanning imaging. By employing deconvolution of the two images with corresponding given priors, the image quality of the deblurred images are compared. Then we find the critical size of the donut shape compared with the Gaussian shape which has similar deconvolution results. Through calculation of tightened focusing process using radially polarized beam, such size of donut is achievable under same conditions. Results: The effects of different relative size of donut and Gaussian shapes are investigated. When the full width at half maximum (FWHM) ratio of donut and Gaussian shape is set about 1.83, similar resolution results are obtained through our deconvolution method. Decreasing the size of donut will favor the deconvolution method. A mask with both amplitude and phase modulation is used to create a donut-shaped PSF compared with the non-modulated Gaussian PSF. Donut with size smaller than our critical value is obtained. Conclusion: The utility of donutshaped PSF are proved useful and achievable in the imaging and deconvolution processing, which is expected to have potential practical applications in high resolution imaging for biological samples.« less

Evaluation of Elevation, Slope and Stream Network Quality of SPOT Dems

NASA Astrophysics Data System (ADS)

El Hage, M.; Simonetto, E.; Faour, G.; Polidori, L.

2012-07-01

Digital elevation models are considered the most useful data for dealing with geomorphology. The quality of these models is an important issue for users. This quality concerns position and shape. Vertical accuracy is the most assessed in many studies and shape quality is often neglected. However, both of them have an impact on the quality of the final results for a particular application. For instance, the elevation accuracy is required for orthorectification and the shape quality for geomorphology and hydrology. In this study, we deal with photogrammetric DEMs and show the importance of the quality assessment of both elevation and shape. For this purpose, we produce several SPOT HRV DEMs with the same dataset but with different template size, that is one of the production parameters from optical images. Then, we evaluate both elevation and shape quality. The shape quality is assessed with in situ measurements and analysis of slopes as an elementary shape and stream networks as a complex shape. We use the fractal dimension and sinuosity to evaluate the stream network shape. The results show that the elevation accuracy as well as the slope accuracy are affected by the template size. Indeed, an improvement of 1 m in the elevation accuracy and of 5 degrees in the slope accuracy has been obtained while changing this parameter. The elevation RMSE ranges from 7.6 to 8.6 m, which is smaller than the pixel size (10 m). For slope, the RMSE depends on the sampling distance. With a distance of 10 m, the minimum slope RMSE is 11.4 degrees. The stream networks extracted from these DEMs present a higher fractal dimension than the reference river. Moreover, the fractal dimension of the extracted networks has a negligible change according to the template size. Finally, the sinuosity of the stream networks is slightly affected by the change of the template size.

Variable-Domain Displacement Transfer Functions for Converting Surface Strains into Deflections for Structural Deformed Shape Predictions

NASA Technical Reports Server (NTRS)

Ko, William L.; Fleischer, Van Tran

2015-01-01

Variable-Domain Displacement Transfer Functions were formulated for shape predictions of complex wing structures, for which surface strain-sensing stations must be properly distributed to avoid jointed junctures, and must be increased in the high strain gradient region. Each embedded beam (depth-wise cross section of structure along a surface strain-sensing line) was discretized into small variable domains. Thus, the surface strain distribution can be described with a piecewise linear or a piecewise nonlinear function. Through discretization, the embedded beam curvature equation can be piece-wisely integrated to obtain the Variable-Domain Displacement Transfer Functions (for each embedded beam), which are expressed in terms of geometrical parameters of the embedded beam and the surface strains along the strain-sensing line. By inputting the surface strain data into the Displacement Transfer Functions, slopes and deflections along each embedded beam can be calculated for mapping out overall structural deformed shapes. A long tapered cantilever tubular beam was chosen for shape prediction analysis. The input surface strains were analytically generated from finite-element analysis. The shape prediction accuracies of the Variable- Domain Displacement Transfer Functions were then determined in light of the finite-element generated slopes and deflections, and were fofound to be comparable to the accuracies of the constant-domain Displacement Transfer Functions

A multiscale, hierarchical model of pulse dynamics in arid-land ecosystems

USGS Publications Warehouse

Collins, Scott L.; Belnap, Jayne; Grimm, N. B.; Rudgers, J. A.; Dahm, Clifford N.; D'Odorico, P.; Litvak, M.; Natvig, D. O.; Peters, Douglas C.; Pockman, W. T.; Sinsabaugh, R. L.; Wolf, B. O.

2014-01-01

Ecological processes in arid lands are often described by the pulse-reserve paradigm, in which rain events drive biological activity until moisture is depleted, leaving a reserve. This paradigm is frequently applied to processes stimulated by one or a few precipitation events within a growing season. Here we expand the original framework in time and space and include other pulses that interact with rainfall. This new hierarchical pulse-dynamics framework integrates space and time through pulse-driven exchanges, interactions, transitions, and transfers that occur across individual to multiple pulses extending from micro to watershed scales. Climate change will likely alter the size, frequency, and intensity of precipitation pulses in the future, and arid-land ecosystems are known to be highly sensitive to climate variability. Thus, a more comprehensive understanding of arid-land pulse dynamics is needed to determine how these ecosystems will respond to, and be shaped by, increased climate variability.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Richen; Guo, Hanqi; Yuan, Xiaoru

Most of the existing approaches to visualize vector field ensembles are to reveal the uncertainty of individual variables, for example, statistics, variability, etc. However, a user-defined derived feature like vortex or air mass is also quite significant, since they make more sense to domain scientists. In this paper, we present a new framework to extract user-defined derived features from different simulation runs. Specially, we use a detail-to-overview searching scheme to help extract vortex with a user-defined shape. We further compute the geometry information including the size, the geo-spatial location of the extracted vortexes. We also design some linked views tomore » compare them between different runs. At last, the temporal information such as the occurrence time of the feature is further estimated and compared. Results show that our method is capable of extracting the features across different runs and comparing them spatially and temporally.« less

TRUMP. Transient & S-State Temperature Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elrod, D.C.; Turner, W.D.

1992-03-03

TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady-state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complex shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position,more » and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time-steps or on the computer time, and attainment of steady state.« less

Object view in spatial system dynamics: a grassland farming example

PubMed Central

Neuwirth, Christian; Hofer, Barbara; Schaumberger, Andreas

2016-01-01

Abstract Spatial system dynamics (SSD) models are typically implemented by linking stock variables to raster grids while the use of object representations of human artefacts such as buildings or ownership has been limited. This limitation is addressed by this article, which demonstrates the use of object representations in SSD. The objects are parcels of land that are attributed to grassland farms. The model simulates structural change in agriculture, i.e., change in the size of farms. The aim of the model is to reveal relations between structural change, farmland fragmentation and variable farmland quality. Results show that fragmented farms tend to become consolidated by structural change, whereas consolidated initial conditions result in a significant increase of fragmentation. Consolidation is reinforced by a dynamic land market and high transportation costs. The example demonstrates the capabilities of the object-based approach for integrating object geometries (parcel shapes) and relations between objects (distances between parcels) dynamically in SSD. PMID:28190972

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elrod, D.C.; Turner, W.D.

TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady-state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complex shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position,more » and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time-steps or on the computer time, and attainment of steady state.« less

Acidification reduced growth rate but not swimming speed of larval sea urchins.

PubMed

Chan, Kit Yu Karen; García, Eliseba; Dupont, Sam

2015-05-15

Swimming behaviors of planktonic larvae impact dispersal and population dynamics of many benthic marine invertebrates. This key ecological function is modulated by larval development dynamics, biomechanics of the resulting morphology, and behavioral choices. Studies on ocean acidification effects on larval stages have yet to address this important interaction between development and swimming under environmentally-relevant flow conditions. Our video motion analysis revealed that pH covering present and future natural variability (pH 8.0, 7.6 and 7.2) did not affect age-specific swimming of larval green urchin Strongylocentrotus droebachiensis in still water nor in shear, despite acidified individuals being significantly smaller in size (reduced growth rate). This maintenance of speed and stability in shear was accompanied by an overall change in size-corrected shape, implying changes in swimming biomechanics. Our observations highlight strong evolutionary pressure to maintain swimming in a varying environment and the plasticity in larval responses to environmental change.

Melt infiltration of silicon carbide compacts. I - Study of infiltration dynamics

NASA Technical Reports Server (NTRS)

Asthana, Rajiv; Rohatgi, Pradeep K.

1992-01-01

Countergravity, pressure-assisted infiltration with a 2014 Al alloy of suitably tamped porous compacts of platelet shaped single crystals of alpha (hexagonal) silicon carbide was used to measure particulate wettability and infiltration kinetics under dynamic conditions relevant to pressure casting of composites. A threshold pressure P(th) for ingression of the infiltrant was identified based on the experimental penetration length versus pressure profiles for a range of experimental variables which included infiltration pressure, infiltration time, SiC size and SiC surface chemistry. The results showed that P(th) decreased whereas the penetration length increased with increasing SiC size and infiltration time. Cu-coated SiC led to lower P(th) and larger penetration lengths compared to uncoated SiC under identical conditions. These observations have been discussed in the light of theoretical models of infiltration and the kinetics of wetting.

The Geometric Phase of Stock Trading.

PubMed

Altafini, Claudio

2016-01-01

Geometric phases describe how in a continuous-time dynamical system the displacement of a variable (called phase variable) can be related to other variables (shape variables) undergoing a cyclic motion, according to an area rule. The aim of this paper is to show that geometric phases can exist also for discrete-time systems, and even when the cycles in shape space have zero area. A context in which this principle can be applied is stock trading. A zero-area cycle in shape space represents the type of trading operations normally carried out by high-frequency traders (entering and exiting a position on a fast time-scale), while the phase variable represents the cash balance of a trader. Under the assumption that trading impacts stock prices, even zero-area cyclic trading operations can induce geometric phases, i.e., profits or losses, without affecting the stock quote.

High Performance Compression of Science Data

NASA Technical Reports Server (NTRS)

Storer, James A.; Carpentieri, Bruno; Cohn, Martin

1994-01-01

Two papers make up the body of this report. One presents a single-pass adaptive vector quantization algorithm that learns a codebook of variable size and shape entries; the authors present experiments on a set of test images showing that with no training or prior knowledge of the data, for a given fidelity, the compression achieved typically equals or exceeds that of the JPEG standard. The second paper addresses motion compensation, one of the most effective techniques used in interframe data compression. A parallel block-matching algorithm for estimating interframe displacement of blocks with minimum error is presented. The algorithm is designed for a simple parallel architecture to process video in real time.

A study of delamination buckling of laminates

NASA Technical Reports Server (NTRS)

Mukherjee, Yu-Xie; Xie, Zhi-Cheng; Ingraffea, Anthony

1990-01-01

The subject of this paper is the buckling of laminated plates, with a preexisting delamination, subjected to in-plane loading. Each laminate is modelled as an orthotropic Mindlin plate. The analysis is carried out by a combination of the finite element and asymptotic expansion methods. By applying the finite element method, plates with general delamination regions can be studied. The asymptotic expansion method reduces the number of unknown variables of the eigenvalue equation to that of the equation for a single Kirchhoff plate. Numerical results are presented for several examples. The effects of the shape, size, and position of the delamination on the buckling load are studied through these examples.

Evaluation of Cloud-Resolving Model Intercomparison Simulations Using TWP-ICE Observations: Precipitation and Cloud Structure

NASA Technical Reports Server (NTRS)

Varble, Adam; Fridlind, Ann M.; Zipser, Edward J.; Ackerman, Andrew S.; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; McFarlane, Sally A.; Pinty, Jean-Pierre; Shipway, Ben

2011-01-01

The Tropical Warm Pool.International Cloud Experiment (TWP ]ICE) provided extensive observational data sets designed to initialize, force, and constrain atmospheric model simulations. In this first of a two ]part study, precipitation and cloud structures within nine cloud ]resolving model simulations are compared with scanning radar reflectivity and satellite infrared brightness temperature observations during an active monsoon period from 19 to 25 January 2006. Seven of nine simulations overestimate convective area by 20% or more leading to general overestimation of convective rainfall. This is balanced by underestimation of stratiform rainfall by 5% to 50% despite overestimation of stratiform area by up to 65% because of a preponderance of very low stratiform rain rates in all simulations. All simulations fail to reproduce observed radar reflectivity distributions above the melting level in convective regions and throughout the troposphere in stratiform regions. Observed precipitation ]sized ice reaches higher altitudes than simulated precipitation ]sized ice despite some simulations that predict lower than observed top ]of ]atmosphere infrared brightness temperatures. For the simulations that overestimate radar reflectivity aloft, graupel is the cause with one ]moment microphysics schemes whereas snow is the cause with two ]moment microphysics schemes. Differences in simulated radar reflectivity are more highly correlated with differences in mass mean melted diameter (Dm) than differences in ice water content. Dm is largely dependent on the mass ]dimension relationship and gamma size distribution parameters such as size intercept (N0) and shape parameter (m). Having variable density, variable N0, or m greater than zero produces radar reflectivities closest to those observed.

Estimation of representative elementary volume for DNAPL saturation and DNAPL-water interfacial areas in 2D heterogeneous porous media

NASA Astrophysics Data System (ADS)

Wu, Ming; Cheng, Zhou; Wu, Jianfeng; Wu, Jichun

2017-06-01

Representative elementary volume (REV) is important to determine properties of porous media and those involved in migration of contaminants especially dense nonaqueous phase liquids (DNAPLs) in subsurface environment. In this study, an experiment of long-term migration of the commonly used DNAPL, perchloroethylene (PCE), is performed in a two dimensional (2D) sandbox where several system variables including porosity, PCE saturation (Soil) and PCE-water interfacial area (AOW) are accurately quantified by light transmission techniques over the entire PCE migration process. Moreover, the REVs for these system variables are estimated by a criterion of relative gradient error (εgi) and results indicate that the frequency of minimum porosity-REV size closely follows a Gaussian distribution in the range of 2.0 mm and 8.0 mm. As experiment proceeds in PCE infiltration process, the frequency and cumulative frequency of both minimum Soil-REV and minimum AOW-REV sizes change their shapes from the irregular and random to the regular and smooth. When experiment comes into redistribution process, the cumulative frequency of minimum Soil-REV size reveals a linear positive correlation, while frequency of minimum AOW-REV size tends to a Gaussian distribution in the range of 2.0 mm-7.0 mm and appears a peak value in 13.0 mm-14.0 mm. Undoubtedly, this study will facilitate the quantification of REVs for materials and fluid properties in a rapid, handy and economical manner, which helps enhance our understanding of porous media and DNAPL properties at micro scale, as well as the accuracy of DNAPL contamination modeling at field-scale.

The Kepler Mission: A Photometric Search for Earthlike Planets

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; Borucki, William; Koch, David; Young, Richard E. (Technical Monitor)

1998-01-01

If Earth lies in or near the orbital plane of an extrasolar planet, that planet passes in front of the disk of its star once each orbit as viewed from Earth. Precise photometry can reveal such transits, which can be distinguished from rotationally-modulated starspots and intrinsic stellar variability by their periodicity, square-well shapes and relative spectral neutrality. Transit observations would provide the size and orbital period of the detected planet. Although geometrical considerations limit the fraction of planets detectable by this technique, many stars can be surveyed within the field of view of one telescope, so transit photometry is quite efficient. Scintillation in and variability of Earth's atmosphere limit photometric precision to roughly one-thousandth of a magnitude, allowing detection of transits by Jupiter-sized planets but not by Earth-sized planets from the ground. The COROT spacecraft will be able to detect Uranus-sized planets orbiting near stars. The Kepler Mission, which is being proposed to NASA's Discovery Program this year, will have a photometer with a larger aperture (1 meter) than will COROT, so it will be able to detect transits by planets as small as Earth. Moreover, the Kepler mission will examine the same star field for four years, allowing confirmation of planets with orbital periods of a year. If the Sun's planetary system is typical for single stars, Kepler should detect approximately 480 terrestrial planets. Assuming the statistics from radial velocity surveys are typical, Kepler should also detect transits of 150 inner giant planets and reflected light variations of 1400 giant planets with orbital periods of less than one week.

Optimum size of nanorods for heating application

NASA Astrophysics Data System (ADS)

Seshadri, G.; Thaokar, Rochish; Mehra, Anurag

2014-08-01

Magnetic nanoparticles (MNP's) have become increasingly important in heating applications such as hyperthermia treatment of cancer due to their ability to release heat when a remote external alternating magnetic field is applied. It has been shown that the heating capability of such particles varies significantly with the size of particles used. In this paper, we theoretically evaluate the heating capability of rod-shaped MNP's and identify conditions under which these particles display highest efficiency. For optimally sized monodisperse particles, the power generated by rod-shaped particles is found to be equal to that generated by spherical particles. However, for particles which are not mono dispersed, rod-shaped particles are found to be more effective in heating as a result of the greater spread in the power density distribution curve. Additionally, for rod-shaped particles, a dispersion in the radius of the particle contributes more to the reduction in loss power when compared to a dispersion in the length. We further identify the optimum size, i.e the radius and length of nanorods, given a bi-variate log-normal distribution of particle size in two dimensions.

Size, Shape and Impurity Effects on Superconducting critical temperature.

NASA Astrophysics Data System (ADS)

Umeda, Masaki; Kato, Masaru; Sato, Osamu

Bulk superconductors have their own critical temperatures Tc. However, for a nano-structured superconductor, Tc depends on size and shape of the superconductor. Nishizaki showed that the high pressure torsion on bulks of Nb makes Tc higher, because the torsion makes many nano-sized fine grains in the bulks. However the high pressure torsion on bulks of V makes Tc lower, and Nishizaki discussed that the decrease of Tc is caused by impurities in the bulks of V. We studied size, shape, and impurity effects on Tc, by solving the Gor'kov equations, using the finite element method. We found that smaller and narrower superconductors show higher Tc. We found how size and shape affects Tc by studying spacial order parameter distributions and quasi-particle eigen-energies. Also we studied the impurity effects on Tc, and found that Tc decreases with increase of scattering rate by impurities. This work was supported in part of KAKENHI Grant Number JP26400367 and JP16K05460, and program for leading graduate schools of ministry of education, culture, sports, science and technology-Japan.

Clear cell trichoblastoma: a clinicopathological and ultrastructural study of two cases.

PubMed

Kazakov, Dmitry V; Mentzel, Thomas; Erlandson, Robert A; Mukensnabl, Petr; Michal, Michal

2006-06-01

Clear cell change in basal cell carcinomas is a well-recognized phenomenon, but is obviously rare in trichoblastomas. We present two cases of clear cell trichoblastoma in which clear cell change was very much prominent, and the results of an ultrastructural study intended to explore the basis of that feature. Both our patients were women, aged 56 and 77 years, who presented with solitary, slowly growing nodules that measured 3 to 5 cm in largest dimension and were located on the scalp and the flexor aspect of the lower arm. Microscopically, the tumors in both cases were symmetric, non-ulcerated, and composed of variably sized and shaped (cribriform, racemiform, strands, cords, nodules) aggregations of monomorphous basaloid epithelial cells that were associated with a specific trichogenic stroma. Common to both tumors was clear cell cytoplasm evident in the majority of the epithelial cells in one case and almost in the entire epithelial cell population in the other. In most epithelial aggregations the epithelial cells with clear cytoplasm often appeared columnar and were arranged in a palisade along a recognizable basal membrane, thus indicative of outer sheath differentiation at the bulb. There were other signs of follicular differentiation. Ultrastructurally, variably sized clusters of uniform small basaloid epithelial cells were separated from the stroma by a thin discontinuous basement membrane. In addition to the usual organelles, the cytoplasm contained fairly conspicuous tonofilaments and variably sized vacuoles devoid of a limiting membrane, located between the palisaded nuclei and the outer cell membrane. The majority of vacuoles were empty, although clumps of a finely granular substance were occasionally evident. No distinct lipid droplets or glycogen particles were identified. The basaloid cells were joined by scattered small desmosomes. These findings were consistent with trichilemmal differentiation at the bulb.

The evolution of avian wing shape and previously unrecognized trends in covert feathering

PubMed Central

Wang, Xia; Clarke, Julia A.

2015-01-01

Avian wing shape has been related to flight performance, migration, foraging behaviour and display. Historically, linear measurements of the feathered aerofoil and skeletal proportions have been used to describe this shape. While the distribution of covert feathers, layered over the anterior wing, has long been assumed to contribute to aerofoil properties, to our knowledge no previous studies of trends in avian wing shape assessed their variation. Here, these trends are explored using a geometric–morphometric approach with landmarks describing the wing outline as well as the extent of dorsal and ventral covert feathers for 105 avian species. We find that most of the observed variation is explained by phylogeny and ecology but shows only a weak relationship with previously described flight style categories, wing loading and an investigated set of aerodynamic variables. Most of the recovered variation is in greater primary covert feather extent, followed by secondary feather length and the shape of the wing tip. Although often considered a plastic character strongly linked to flight style, the estimated ancestral wing morphology is found to be generally conservative among basal parts of most major avian lineages. The radiation of birds is characterized by successive diversification into largely distinct areas of morphospace. However, aquatic taxa show convergence in feathering despite differences in flight style, and songbirds move into a region of morphospace also occupied by basal taxa but at markedly different body sizes. These results have implications for the proposed inference of flight style in extinct taxa. PMID:26446812

Anatomically shaped cranial collimation (ACC) for lateral cephalometric radiography: a technical report.

PubMed

Hoogeveen, R C; van der Stelt, P F; Berkhout, W E R

2014-01-01

Lateral cephalograms in orthodontic practice display an area cranial of the base of the skull that is not required for diagnostic evaluation. Attempts have been made to reduce the radiation dose to the patient using collimators combining the shielding of the areas above the base of the skull and below the mandible. These so-called "wedge-shaped" collimators have not become standard equipment in orthodontic offices, possibly because these collimators were not designed for today's combination panoramic-cephalometric imaging systems. It also may be that the anatomical variability of the area below the mandible makes this area unsuitable for standardized collimation. In addition, a wedge-shaped collimator shields the cervical vertebrae; therefore, assessment of skeletal maturation, which is based on the stage of development of the cervical vertebrae, cannot be performed. In this report, we describe our investigations into constructing a collimator to be attached to the cephalostat and shield the cranial area of the skull, while allowing the visualization of diagnostically relevant structures and markedly reducing the size of the irradiated area. The shape of the area shielded by this "anatomically shaped cranial collimator" (ACC) was based on mean measurements of cephalometric landmarks of 100 orthodontic patients. It appeared that this collimator reduced the area of irradiation by almost one-third without interfering with the imaging system or affecting the quality of the image. Further research is needed to validate the clinical efficacy of the collimator.

Surface integrity on grinding of gamma titanium aluminide intermetallic compounds

NASA Astrophysics Data System (ADS)

Murtagian, Gregorio Roberto

Gamma-TiAl is an ordered intermetallic compound characterized by high strength to density ratio, good oxidation resistance, and good creep properties at elevated temperatures. However, it is intrinsically brittle at room temperature. This thesis investigates the potential for the use of grinding to process TiAl into useful shapes. Grinding is far from completely understood, and many aspects of the individual mechanical interactions of the abrasive grit with the material and their effect on surface integrity are unknown. The development of new synthetic diamond superabrasives in which shape and size can be controlled raises the question of the influence of those variables on the surface integrity. The goal of this work is to better understand the fundamentals of the abrasive grit/material interaction in grinding operations. Experimental, analytical, and numerical work was done to characterize and predict the resultant deformation and surface integrity on ground lamellar gamma-TiAl. Grinding tests were carried out, by analyzing the effects of grit size and shape, workpiece speed, wheel depth of cut, and wear on the subsurface plastic deformation depth (PDD). A practical method to assess the PDD is introduced based on the measurement of the lateral material flow by 3D non-contact surface profilometry. This method combines the quantitative capabilities of the microhardness measurement with the sensitivity of Nomarski microscopy. The scope and limitations of this technique are analyzed. Mechanical properties were obtained by quasi-static and split Hopkinson bar compression tests. Residual stress plots were obtained by x-ray, and surface roughness and cracking were evaluated. The abrasive grit/material interaction was accounted by modeling the force per abrasive grit for different grinding conditions, and studying its correlation to the PDD. Numerical models of this interaction were used to analyze boundary conditions, and abrasive size effects on the PDD. An explicit 2D triple planar slip crystal plasticity model of single point scratching was used to analyze the effects of lamellae orientation, material anisotropy, and grain boundaries on the deformation.