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Linear Dimensions (linear + dimension)
Selected AbstractsConvergence in the macroscopic anatomy of the reticulum in wild ruminant species of different feeding types and a new resulting hypothesis on reticular functionJOURNAL OF ZOOLOGY, Issue 1 2010M. Clauss Abstract The reticulum is the second part of the ruminant forestomach, located between the rumen and the omasum and characterized by honeycomb-like internal mucosa. With its fluid contents, it plays a decisive role in particle separation. Differences among species have been linked to their feeding style. We investigated whether reticulum size (absolute and in relation to rumen size) and size of the crests that form the mucosal honeycomb pattern differ among over 60 ruminant species of various body sizes and feeding type, controlling for phylogeny. Linear dimensions generally scaled allometrically, that is to body mass0.33. With or without controlling for phylogeny, species that ingest a higher proportion of grass in their natural diet had both significantly larger (higher) rumens and higher reticular mucosa crests, but neither reticulum height nor reticulum width varied with feeding type. The height of the reticular mucosa crests represents a dietary adaptation in ruminants. We suggest that the reticular honeycomb structures do not separate particles by acting as traps (neither for small nor for large particles), but that the structures reduce the lumen of the reticulum during contractions , at varying degrees of completeness in the different feeding types. In browsing species with rumen contents that may be less fluid and more viscous than those of the reticulum, incomplete closure of the lumen may allow the reticulum to retain the fluid necessary for particle separation. In grazing species, whose rumen contents are more stratified with a larger distinct fluid pool, a more complete closure of the reticular lumen due to higher crests may be beneficial as the reticulum can quickly re-fill with fluid rumen contents that contain pre-sorted particles. [source] Is the Presence of Mitral Annular Calcification Associated with Poor Left Atrial Function?ECHOCARDIOGRAPHY, Issue 8 2009Vignendra Ariyarajah M.D. Introduction: Mitral annular calcification (MAC) is characterized by calcium and lipid deposition in the annular fibrosa of the mitral valve. MAC is associated with cardiovascular events but little is known of its association with left atrial (LA) function. Methods: We prospectively obtained 12-lead electrocardiograms (ECGs) and transthoracic echocardiograms (TTE) on patients scheduled for nonemergent echocardiographic assessment at a tertiary care hospital. MAC was graded as 0 = none, 1 = mild, 2 = moderate, 3 = severe. LA linear and volume measurements (stroke volume, LA passive emptying fraction, LA active emptying fraction and LA kinetic energy) were done specifically in addition to commonly measured TTE parameters. Results: From the 124 considered for the study, 72 patients remained (aged 68±18 years; 44% male) after excluding those with poor ECG tracings and/or poor TTE images. Eighteen patients had MAC; mild MAC = 14, moderate MAC = 3, severe MAC = 1. When patients with MAC were compared to those without MAC, no significant difference was noted, except for LA linear dimension index (2.1±0.4 vs. 1.9±0.3 cm/m2; P = 0.03). For those with mild and moderate MAC, a trend was noted toward lower LA function with increasing MAC severity. In addition, significant differences were noted between those with and without interatrial conduction delay, where those with such delay had significantly impaired LA stroke volume (9.8±3 vs. 19.93±4 ml; P < 0.0001), LA active emptying fraction (18.83±8 vs. 65.71±9%; P < 0.0001) and LA total/reservoir fraction (39.54±6 vs. 75.1±6%; P < 0.0001). Conclusions: MAC is associated with increase in LA linear dimension on TTE and may be equally represented with lower overall LA function. Further study in a much larger cohort is warranted to delineate these and other potential associations of MAC. [source] Experimental evaluation of creep and fatigue behaviour for microscale solder interconnectFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 2 2007H. LU ABSTRACT This paper presents a novel experimental study for creep and fatigue of solder-interconnects in microstructures. The strains are directly measured in the fillet area of solder-joints with a typical linear dimension of 50 ,m. An analytical approach is developed for calculating shear stress based on the shear strain measurement and the established solder constitutive relations. Also obtained is the strain-rate as well as the separated elastic, plastic and creep components from the measured total strain. The data enables the determination of the strain energy density per temperature cycle for the characterization of the solder joint creep fatigue behaviour. Case studies provide evidence for the shear dominance and the creep fatigue mechanism in thermally induced solder joint deformation in surface-mounted electronic assemblies. Though a similar trend of variation in stress,strain is found in the joints of different solders, the substantial differences in the hysteresis loop area and shape as well as in the creep rate suggest that the solder constitutive parameters should have a profound impact on the creep fatigue endurance of the joints. [source] Picophytoplankton contribution to phytoplankton community structure in the Gulf of Venice (NW Adriatic Sea)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 1 2006Fabrizio Bernardi Aubry Abstract The size distribution of the phytoplankton community has been analyzed on a monthly basis in the Gulf of Venice (NW Adriatic Sea), with the aim to assess the seasonal variation of the contribution of autotrophic picoplankton (APP) to total phytoplankton. The investigation was carried out in two stations characterized by different influences of fluvial inputs. APP was mainly made up of Synechococcus , the larger fraction (Utermöhl Fraction Phytoplankton, UFP: µm as maximum linear dimension) of diatoms and nanoflagellates. The average APP abundance (46 × 103 cells ml,1) and biomass (8.1 µg C dm,3) indicate that APP was a persistent and significant component of the NW Adriatic phytoplankton. The highest APP abundance (up to 270 × 103 cells ml,1) and biomass (up to 49 µg C dm,3) were recorded from summer to autumn, UFP peaked from late winter to late spring. The mean APP contribution to total phytoplankton abundance and biomass was 98% and 31% respectively. The seasonal variation of total phytoplankton biomass was mainly driven by the UFP fraction; however, a seasonal shift in the relative importance of UFP and APP occurred from spring to summer. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Miranda cargo-binding domain forms an elongated coiled-coil homodimer in solution: Implications for asymmetric cell division in DrosophilaPROTEIN SCIENCE, Issue 5 2008Mohammad S. Yousef Abstract Miranda is a multidomain adaptor protein involved in neuroblast asymmetric division in Drosophila melanogaster. The central domain of Miranda is necessary for cargo binding of the neural transcription factor Prospero, the Prospero-mRNA carrier Staufen, and the tumor suppressor Brat. Here, we report the first solution structure of Miranda central "cargo-binding" domain (residues 460,660) using small-angle X-ray scattering. Ab initio modeling of the scattering data yields an elongated "rod-like" molecule with a maximum linear dimension (Dmax) of ,22 nm. Moreover, circular dichroism and cross-linking experiments indicate that the cargo-binding domain is predominantly helical and forms a parallel coiled-coil homodimer in solution. Based on the results, we modeled the full-length Miranda protein as a double-headed, double-tailed homodimer with a long central coiled-coil region. We discuss the cargo-binding capacity of the central domain and propose a structure-based mechanism for cargo release and timely degradation of Miranda in developing neuroblasts. [source] PHYSICAL PROPERTIES OF TWO POPULAR INDIAN POTATO VARIETIESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2006D.K. SINGH ABSTRACT Physical properties of potatoes, often required for analyzing heat and mass transfer during cooling and storage applications, were determined for the Kufri Jyoti and Kufri Sinduri varieties. The average values of linear dimensions, Dp, Sp, Ra, mass, ,, Acand A of these two varieties were measured. The Kufri Jyoti was found to have comparatively more variations in a, b and c than the Kufri Sinduri. The average values of Dp, Sp, Ra, ,, Acand A for the Kufri Jyoti and Kufri Sinduri were found to be 4.647 and 3.692 cm; 82.45 and 86.65%; 82.99 and 91.78%; 1113.3 and 1092.1 kg/m3; 30.86 and 12.10 cm2; and 79.05 and 47.10 cm2, respectively. The average values of ,, Dv, average Dpi, ,and bulk density for the Kufri Jyoti and Kufri Sinduri in a commercially used 50-kg gunny bag were found to be 0.42 ± 0.01 and 0.43 ± 0.008; 4.998 and 4.056 cm, 4.817 ± 0.534 and 3.922 ± 0.211 cm, 0.58 and 0.57; and 647.6 and 622.5 kg/m3, respectively. Relationships were also established for calculating the A of potato as a function of volume and weight. [source] The contribution of the swimbladder to buoyancy in the adult zebrafish (Danio rerio): A morphometric analysisJOURNAL OF MORPHOLOGY, Issue 6 2008George N. Robertson Abstract Many teleost fishes use a swimbladder, a gas-filled organ in the coelomic cavity, to reduce body density toward neutral buoyancy, thus minimizing the locomotory cost of maintaining a constant depth in the water column. However, for most swimbladder-bearing teleosts, the contribution of this organ to the attainment of neutral buoyancy has not been quantified. Here, we examined the quantitative contribution of the swimbladder to buoyancy and three-dimensional stability in a small cyprinid, the zebrafish (Danio rerio). In aquaria during daylight hours, adult animals were observed at mean depths from 10.1 ± 6.0 to 14.2 ± 5.6 cm below the surface. Fish mass and whole-body volume were linearly correlated (r2 = 0.96) over a wide range of body size (0.16,0.73 g); mean whole-body density was 1.01 ± 0.09 g cm,3. Stereological estimations of swimbladder volume from linear dimensions of lateral X-ray images and direct measurements of gas volumes recovered by puncture from the same swimbladders showed that results from these two methods were highly correlated (r2 = 0.85). The geometric regularity of the swimbladder thus permitted its volume to be accurately estimated from a single lateral image. Mean body density in the absence of the swimbladder was 1.05 ± 0.04 g cm,3. The swimbladder occupied 5.1 ± 1.4% of total body volume, thus reducing whole-body density significantly. The location of the centers of mass and buoyancy along rostro-caudal and dorso-ventral axes overlapped near the ductus communicans, a constriction between the anterior and posterior swimbladder chambers. Our work demonstrates that the swimbladder of the adult zebrafish contributes significantly to buoyancy and attitude stability. Furthermore, we describe and verify a stereological method for estimating swimbladder volume that will aid future studies of the functions of this organ. J Morphol., 2008. © 2008 Wiley-Liss, Inc. [source] Quantitative radiographic changes in the mandible and the tibia in systemically loaded rats fed a low-calcium dietORAL DISEASES, Issue 5 2000Y Morimoto The combined effect of the duration of loaded physical exercise and the percentage of calcium intake on the mandible and tibia were studied in developing male rats. For the loaded exercise, rats ran on a treadmill at a rate of 12 m per min for either 1 or 2 h per day. A total of 54 4-week-old male Wistar rats were randomly assigned to one of six groups. After 4 weeks of the diet and loaded exercise, the rats were killed and their mandibles and tibia were removed. Each individual bone was assessed by radiography and the radiographs were then used for measurements of cortical thickness, bone length and bone width. All radiographic images were analyzed using a computer-based scanner image analysis system. In addition, we measured the dry weight both of the tibia and mandible. The results demonstrated that significant differences in cortical thickness, bone length, bone width, and bone weight, both of the tibia and the mandible, were detectable between the normal diet group and the low-calcium diet group. Among the normal diet groups, significant differences were found in cortical thickness, bone length, bone width, and bone weight of the tibia, whereas no significant differences in either cortical bone thickness, bone length or bone weight of the mandible were detected. In contrast, among the low-calcium diet groups, no significant differences were detected in cortical thickness, bone length, bone width or bone weight for either the tibia or the mandible. Our results suggested that systemic exercise, such as running, promote the linear dimensions and the cortical thickness of the tibia in response to local stimuli. Furthermore, sufficient calcium intake appears to be necessary to allow the effect of systemic exercise on tibial bone growth to occur. In contrast, systemic loaded exercise does not promote either bone growth or development of the mandible even under conditions of sufficient calcium intake. [source] SYSTEMATICS OF THE CAMBRIAN TRILOBITE FAMILY NEPEIDAE, WITH REVISION OF AUSTRALIAN SPECIESPALAEONTOLOGY, Issue 3 2005JOHN R. PATERSON Abstract:, Taxonomy of the Cambrian trilobite family Nepeidae is revised. Morphometric analyses of the genera Nepea and Penarosa demonstrate that use of proportions of linear dimensions of the cranidium to differentiate species is invalid, and that infrageneric variation is continuous. The taxonomy and biostratigraphy of all Australian species of Nepeidae is revised. Species considered valid herein include: Nepea narinosa (type species), N. tonsillata, N. nans, Penarosa retifera (type species), P. elaticeps, P. rhinodelphis, P. netenta, Loxonepea loxophrys (type species) and Ferenepea hispida (type species). Folliceps is considered to be a junior subjective synonym of Nepea, Trinepea is regarded as a junior subjective synonym of Penarosa, and Ascionepea is considered to be a junior subjective synonym of Ferenepea. [source] Growth patterns in adverse environmentsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2007Noël Cameron The triple-logistic pattern of human growth in linear dimensions is probably one of the most recognizable models within human biology. The fact that postnatal somatic growth occurs in three phases (infancy, childhood, adolescence) creates opportunities for the individual expression of this genetically directed, but environmentally modified, phenomenon. The impact of the environment works to alter the duration and intensity of critical stages within the total process resulting in individual patterns that can differ radically from the general pattern. However, the constancy of the general pattern is so fixed that its presence in children is taken as a reflection of good health. Departures from that pattern are recognized as reflecting ill health. While the cessation of growth in response to an acute attack is uniformly dramatic, the gradual response to chronic adverse stimuli is less easily predicted and interpreted. For example, in chronic scenarios the loss of centile position that precedes the eventual establishment of normal increments can be viewed as either a poor or a good growth response, as either maladaptive or adaptive, as either poor health or good health. This article reviews such growth patterns in urban South African children exploring the relationship between environment and growth outcome. Am. J. Hum. Biol., 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||