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Relative Distribution (relative + distribution)
Selected AbstractsRelative distribution of three major lactate transporters in frozen human tissues and their localization in unfixed skeletal muscleMUSCLE AND NERVE, Issue 1 2002William N. Fishbein MD Abstract We have prepared affinity-purified rabbit polyclonal antibodies to the near-C-terminal peptides of human monocarboxylate transporters (MCTs) 1, 2, and 4 coupled to keyhole limpet hemocyanin. Each antiserum reacted only with its specific peptide antigen and gave a distinct molecular weight band (blocked by preincubation with antigen) after chemiluminescence reaction on Western blots from sodium dodecyl sulfate,polyacrylamide gel electrophoresis (SDS-PAGE) of tissue membrane proteins. Densitometry showed distinctive expression patterns for each MCT in a panel of 15 frozen human tissues, with the distribution of MCT1 ,L:MCT2>MCT4. Fluorescence microscopy of unfixed skeletal muscle using fluorescein-conjugated secondary antibody was correlated with reverse adenosine triphosphatase (ATPase) stained sequential sections to identify fiber-type localization. MCT1 expression was high in the sarcolemma of type 1 fibers, modest to low in type 2a fibers, and almost absent in type 2b fibers. In contrast, MCT4 expression was low to absent in the membrane of most type 1 fibers, but high in most 2a and in all 2b fibers, favoring the view that their high lactate levels during work may be channeled in part to neighboring type 1 (and perhaps 2a) fibers for oxidation, thereby delaying fatigue. MCT2 expression was limited to the sarcolemma of a type 1 fiber subset, which varied from <5 to 40%, depending on the specific muscle under study. Quantitative chemiluminescent densitometry of 10 muscle biopsies for their MCT2 and MCT4 content, each normalized to MCT1, confirmed the unique variation of MCT2 expression with biopsy site. The application of these antibodies should add to the understanding of motor unit physiology, and may contribute to the muscle-biopsy assessment of low-level denervation. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 101,112, 2002 [source] Invasion by Rattus rattus into native coastal forests of south-eastern Australia: are native small mammals at risk?AUSTRAL ECOLOGY, Issue 4 2009VICKI L. STOKES Abstract The black rat, Rattus rattus, is an alien rodent in Australian ecosystems where niche overlap with native small mammals may lead to competition for resources and displacement of native species. In coastal habitats surrounding Jervis Bay in south-eastern Australia, R. rattus co-occurs with the native bush rat, Rattus fuscipes, and brown antechinus, Antechinus stuartii. Relative distributions and abundances, and fine-scale space use suggest invasive and native rodents compete for use of space and habitat. Such competitive interactions were not evident between R. rattus and native A. stuartii, which was negatively influenced more by disturbance to habitat. Differences in rodent communities between spatially separate forests forming the northern and southern peninsulas of Jervis Bay potentially reflect symmetrical competition and differences in competitive outcomes. In southern forests, R. rattus was largely restricted to patches of disturbed forest associated with campgrounds. Competitive interference by native rodent populations inhabiting surrounding intact forests may have so far limited R. rattus colonization of these areas. In northern forests, R. rattus was the predominant rodent irrespective of disturbance, while populations of R. fuscipes were unusually low seemingly due to poor juvenile recruitment. Native individuals avoided areas frequented by adult R. rattus and given that species did not partition use of microhabitats, R. rattus most likely precluded R. fuscipes from suitable habitat and in doing so limited native populations. We discuss how natural disturbance of habitat and human activity have potentially facilitated successful invasion by R. rattus of the northern forests. Studies that manipulate rodent populations are required to support these interpretations of observed patterns. [source] Position-Invariant Neural Network for Digital Pavement Crack AnalysisCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2004Byoung Jik Lee This system includes three neural networks: (1) image-based neural network, (2) histogram-based neural network, and (3) proximity-based neural network. These three neural networks were developed to classify various crack types based on the subimages (crack tiles) rather than crack pixels in digital pavement images. These spatial neural networks were trained using artificially generated data following the Federal Highway Administration (FHWA) guidelines. The optimal architecture of each neural network was determined based on the testing results from different sets of the number of hidden units, learning coefficients, and the number of training epochs. To validate the system, actual pavement pictures taken from pavements as well as the computer-generated data were used. The proximity value is determined by computing relative distribution of crack tiles within the image. The proximity-based neural network effectively searches the patterns of various crack types in both horizontal and vertical directions while maintaining its position invariance. The final result indicates that the proximity-based neural network produced the best result with the accuracy of 95.2% despite its simplest neural network structure with the least computing requirement. [source] The role of spatial scale and the perception of large-scale species-richness patternsECOLOGY LETTERS, Issue 2 2005Carsten Rahbek Abstract Despite two centuries of exploration, our understanding of factors determining the distribution of life on Earth is in many ways still in its infancy. Much of the disagreement about governing processes of variation in species richness may be the result of differences in our perception of species-richness patterns. Until recently, most studies of large-scale species-richness patterns assumed implicitly that patterns and mechanisms were scale invariant. Illustrated with examples and a quantitative analysis of published data on altitudinal gradients of species richness (n = 204), this review discusses how scale effects (extent and grain size) can influence our perception of patterns and processes. For example, a hump-shaped altitudinal species-richness pattern is the most typical (c. 50%), with a monotonic decreasing pattern (c. 25%) also frequently reported, but the relative distribution of patterns changes readily with spatial grain and extent. If we are to attribute relative impact to various factors influencing species richness and distribution and to decide at which point along a spatial and temporal continuum they act, we should not ask only how results vary as a function of scale but also search for consistent patterns in these scale effects. The review concludes with suggestions of potential routes for future analytical exploration of species-richness patterns. [source] Subcellular cadmium distribution, accumulation, and toxicity in a predatory gastropod, Thais clavigera, fed different preyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006Ma-Shan Cheung Abstract Bioaccumulation and toxicity of Cd were investigated in a marine predatory whelk, Thais clavigera, after being fed with the rock oyster, Saccostrea cucullata, or the herbivorous snail, Monodonta labio, for up to four weeks. The oysters and snails had different subcellular Cd distributions and concentrations in their bodies given their different metal-handling strategies and were exposed to dissolved Cd for two weeks before being fed to the whelks. After four weeks of dietary exposure, the Cd body concentrations in T. clavigera increased from 3.1 ,g/g to between 22.9 and 41.8 ,g/g and to between 22.7 and 24.1 ,g/g when they were fed with oyster and snail prey, respectively. An increasing proportion of Cd was found to be distributed in the metallothionein (MT)-like proteins and organelle fractions, whereas the relative distribution in the metal-rich granules fraction decreased when the whelks were fed Cd-exposed prey. At the highest Cd dosage, more Cd was distributed in the pool of metal-rich granules when the whelks were fed the oysters than when they were fed the snails. Among all the biomarkers measured (MT induction, condition index, lipid peroxidation, and total energy reserve including carbohydrate, lipid, and protein), only MT showed a significant difference from the control treatments, and MT was the most sensitive biomarker for dietary Cd exposure. No toxicity was found in the whelks fed different Cd-exposed prey as revealed by various biomarkers at the different biological levels. Our results imply that metal fractionation in prey can alter the subsequent subcellular metal distribution in predators and that dietary Cd toxicity to the whelks was low, even when the accumulated Cd body concentrations were high. [source] Wavelet analysis of the scale- and location-dependent correlation of modelled and measured nitrous oxide emissions from soilEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2005A. E. Milne Summary We used the wavelet transform to quantify the performance of models that predict the rate of emission of nitrous oxide (N2O) from soil. Emissions of N2O and other soil variables that influence emissions were measured on soil cores collected at 256 locations across arable land in Bedfordshire, England. Rate-limiting models of N2O emissions were constructed and fitted to the data by functional analysis. These models were then evaluated by wavelet variance and wavelet correlations, estimated from coefficients of the adapted maximal overlap discrete wavelet transform (AMODWT), of the fitted and measured emission rates. We estimated wavelet variances to assess whether the partition of the variance of modelled rates of N2O emission between scales reflected that of the data. Where the relative distribution of variance in the model is more skewed to coarser scales than is the case for the observation, for example, this indicates that the model predictions are too smooth spatially, and fail adequately to represent some of the variation at finer scales. Scale-dependent wavelet correlations between model and data were used to quantify the model performance at each scale, and in several cases to determine the scale at which the model description of the data broke down. We detected significant changes in correlation between modelled and predicted emissions at each spatial scale, showing that, at some scales, model performance was not uniform in space. This suggested that the influence of a soil variable on N2O emissions, important in one region but not in another, had been omitted from the model or modelled poorly. Change points usually occurred at field boundaries or where soil textural class changed. We show that wavelet analysis can be used to quantify aspects of model performance that other methods cannot. By evaluating model behaviour at several scales and positions wavelet analysis helps us to determine whether a model is suitable for a particular purpose. [source] Geranyl acetate esterase is commonly present but linalyl acetate esterase occurrence is highly limited in plantsFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2007Neelam S. Sangwan Abstract Esterases are a group of hydrolytic enzymes that split ester bonds by addition of water and are ubiquitously present in diverse biosystems. Although animal esterases are well studied and are catalytically and functionally classified into different groups, plant enzymes have been viewed rather generally and are casually recruited as biochemical markers in morphogenesis, genetic characterization of plants, etc., without functional emphasis. Some volatile oil plants constitutively synthesize their characteristic monoterpene esters, geranyl acetate and linalyl acetate being the most common among them in the acyclic monoterpene class, whereas other plants also synthesize some volatile hemi- to sesquiterpene esters but inductively under certain ecological situations, such as herbivory, wounding, etc. This study concerns screening relative distribution of geranyl acetate esterase and linalyl aceate esterase activities in selected medicinal and aromatic plants, and reveals that in plants geranyl acetate (a primary alcohol ester) esterase is commonly present, while linalyl acetate (a tertiary alcohol ester) esterase seems to be highly limited to those plants (e.g. Lippia alba, Mentha citrata) that biosynthesize the tertiary monoterpene alcohol linalool and its ester. Such contrasting distribution of the two discrete types of esterases has been discussed in light of scenario of their microbial counterparts and structure,function relationships established thereon. This study makes it obvious that the GGG(A)-X motif esterases (acting on tertiary alcohol esters) are rare entities in plants too, similar to microbes. Furthermore, their presence in some volatile oil plants renders such plants novel phytoresources of the GGGX/GGAX motif hydrolases. Detailed characterization of the motif-specific plant esterases would have an immense impact on understanding of their structure,function relationships in plants. Copyright © 2007 John Wiley & Sons, Ltd. [source] Changes in rat hippocampal CA1 synapses following imipramine treatmentHIPPOCAMPUS, Issue 7 2008Fenghua Chen Abstract Neuronal plasticity in hippocampus is hypothesized to play an important role in both the pathophysiology of depressive disorders and the treatment. In this study, we investigated the consequences of imipramine treatment on neuroplasticity (including neurogenesis, synaptogenesis, and remodelling of synapses) in subregions of the hippocampus by quantifying number of neurons and synapses. Adult male Sprague-Dawley rats were injected with imipramine or saline (i.p.) daily for 14 days. Unbiased stereological methods were used to quantify the number of neurons and synapses. No differences in the volume and number of neurons of hippocampal subregions following imipramine treatment were found. However, the number and percentage of CA1 asymmetric spine synapses increased significantly and, conversely, the percentage of asymmetric shaft synapses significantly decreased in the imipramine treated group. Our results indicate that administration of imipramine for 14 days in normal rats could significantly increase the excitatory spine synapses, and change the relative distribution of spine and shaft synapses. We speculate that the present findings may be explained by the establishment of new synaptic connections and by remodelling or transformation of existing synapses. © 2008 Wiley-Liss, Inc. [source] Long-term changes in the trophic level of the Celtic Sea fish community and fish market price distributionJOURNAL OF APPLIED ECOLOGY, Issue 3 2002J. K. Pinnegar Summary 1The intensive exploitation of fish communities often leads to substantial reductions in the abundance of target species, with ramifications for the structure and stability of the ecosystem as a whole. 2We explored changes in the mean trophic level of the Celtic Sea (ICES divisions VII f,j) fish community using commercial landings, survey data and estimates of trophic level derived from the analysis of nitrogen stable isotopes. 3Our analyses showed that there has been a significant decline in the mean trophic level of survey catches from 1982 to 2000 and a decline in the trophic level of landings from 1946 to 1998. 4The decline in mean trophic level through time resulted from a reduction in the abundance of large piscivorous fishes and an increase in smaller pelagic species which feed at a lower trophic level. 5Similar patterns of decline in the trophic level of both catches and landings imply that there have been substantial changes in the underlying structure of the Celtic Sea fish community and not simply a change in fishery preferences. 6We suggest that the reported changes in trophic structure result from reductions in the spawning stock biomass of traditional target species associated with intensive fishing, together with long-term climate variability. 7The relative distribution of fish market prices has changed significantly over the past 22 years, with high trophic level species experiencing greater price rises than lower trophic level species. 8Although decreased abundance of high trophic level species will ultimately have negative economic consequences, the reduction in mean trophic level of the fish community as a whole may allow the system to sustain higher fishery yields. 9Management objectives in this fishery will depend on the relative values that society attaches to economic profit and protein production. [source] Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, MalaysiaJOURNAL OF BIOGEOGRAPHY, Issue 4 2004Konstans Wells Abstract Aim, Small mammals were live-trapped in a primary rain forest to evaluate the relative distribution of species to each other and to microhabitat properties on the ground and in the canopy. Location, Kinabalu National Park in Borneo, Sabah, Malaysia. Methods, Seven trapping sessions were conducted along two grids with 31 trap points at distances of 20 m on the ground and in the lower canopy at an average height of 13.5 m. Results, Species diversity and abundance of small mammals proved to be high: 20 species of the families Muridae, Sciuridae, Tupaiidae, Hystricidae, Viverridae and Lorisidae were trapped, with murids being dominant in both habitat layers. The terrestrial community was significantly more diverse with 16 captured species (Shannon,Wiener's diversity index = 2.47), while 11 species were trapped in the canopy ( = 1.59). The Whitehead's rat, Maxomys whiteheadi, and the red spiny rat, Maxomys surifer, dominated the terrestrial community whereas the large pencil-tailed tree mouse, Chiropodomys major, was by far the most abundant species in the canopy. Other abundant species of the canopy community, the dark-tailed tree rat, Niviventer cremoriventer, and the lesser treeshrew, Tupaia minor, were also abundant on the ground, and there was no clear boundary between arboreal and terrestrial species occurrences. Main conclusions, As most species were not confined to specific microhabitats or habitat layers, species seemed to rely on resources not necessarily restricted to certain microhabitats or habitat layers, and separation of species probably resulted mainly from a species' concentrated activity in a preferred microhabitat rather than from principal adaptations to certain habitats. Ecological segregation was stronger in the more diverse terrestrial community, though microhabitat selection was generally not sufficient to explain the co-occurrences of species and the variability between local species assemblages. Constraints on small mammal foraging efficiency in the three-dimensional more complex canopy may be responsible for the similarity of microhabitat use of all common arboreal species. Community composition was characterized by mobile species with low persistence rates, resulting in a high degree of variability in local species assemblages with similar turnover rates in both habitats. [source] Texting as a life phase mediumJOURNAL OF COMPUTER-MEDIATED COMMUNICATION, Issue 2 2010Rich Ling SMS has grown to be a common form of interaction in Norwegian society. Its adoption started among teens but has since been taken into use by other age groups. However, the use patterns for teens seem to be different from those of older users. This paper examines the assertion that SMS is a life phase and not a cohort phenomenon. That is, its use is more intense among teens and more moderate among older age groups. Data for the analysis comes from a series of six nation-wide surveys of Norwegians over the age of 13. Questions on the reported use of SMS were included in all these surveys. This information was adjusted in order to remove the effects of generally increased use over time. The analysis shows that the proportion of text messages sent by different age groups stays rather stable over time. Indeed there seems to be a type of "standing wave" of use associated with older teens and those in their early 20s. While there are cohort effects visible in the data, the analysis indicates that texting is largely a life phase phenomenon. If the curve had flattened out with time it would have indicated that the teens are carrying texting with them as they grow older. This, it seems is not the case. The overall use of SMS has increased in Norwegian society but the relative distribution of the text messages has remained centered around those in their late teens. This seems to indicate that the intense use of SMS is a life-phase phenomenon. [source] Distinct properties of murine ,5 ,-aminobutyric acid type a receptors revealed by biochemical fractionation and mass spectroscopyJOURNAL OF NEUROSCIENCE RESEARCH, Issue 8 2009Young H. Ju Abstract ,-Aminobutyric acid type A receptors (GABAARs) that contain the ,5 subunit are expressed predominantly in the hippocampus, where they regulate learning and memory processes. Unlike conventional postsynaptic receptors, GABAARs containing the ,5 subunit (,5 GABAARs) are localized primarily to extrasynaptic regions of neurons, where they generate a tonic inhibitory conductance. The unique characteristics of ,5 GABAARs have been examined with pharmacological, immunostaining, and electrophysiological techniques; however, little is known about their biochemical properties. The aim of this study was to modify existing purification and enrichment techniques to isolate ,5 GABAARs preferentially from the mouse hippocampus and to identify the ,5 subunit by using tandem mass spectroscopy (MS/MS). The results showed that the detergent solubility of the ,5 subunits was distinct from that of ,1 and ,2 subunits, and the relative distribution of the ,5 subunits in Triton X-100-soluble fractions was correlated with that of the extracellular protein radixin but not with that of the postsynaptic protein gephyrin. Mass spectrometry identified the ,5 subunit and showed that this subunit associates with multiple ,, ,, and , subunits, but most frequently the ,3 subunit. Thus, the ,5 subunits coassemble with similar subunits as their synaptic counterparts yet have a distinct detergent solubility profile. Mass spectroscopy now offers a method for detecting and characterizing factors that confer the unique detergent solubility and possibly cellular location of ,5 GABAARs in hippocampal neurons. © 2009 Wiley-Liss, Inc. [source] Commuting, Migration, and Rural-Urban Population DynamicsJOURNAL OF REGIONAL SCIENCE, Issue 2 2000Mitch Renkow Over the past 25 years social scientists attempting to explain the dramatic changes in the relative distribution of urban and rural population growth have gravitated toward two competing explanations. The regional restructuring hypothesis holds that changes in the spatial distribution of employment opportunities have been dominant whereas the deconcentration hypothesis attributes these changes to changes in residential preferences of workers and consumers. We develop an empirical test of these two explanations based on whether commuting and migration are positively or negatively related after controlling for other economic factors. Our econometric results support the deconcentration hypothesis. [source] Phylogeography of the common ivy (Hedera sp.) in Europe: genetic differentiation through space and timeMOLECULAR ECOLOGY, Issue 8 2002D. Grivet Abstract We studied the phylogeography of ivy (Hedera sp.), a liana widespread in Europe, throughout its natural range. The populations sampled belong to four closely related species differing by ploidy levels and morphological characters. Chloroplast (cp) markers were used and 13 haplotypes were detected, usually shared across species, contrary to ribosomal internal transcribed spacer (ITS) variants. We demonstrated the existence of a strong overall cpDNA phylogeographical structure. Several methods of data analysis were conducted to describe how this structure and the genetic diversity change through space and time. Southern populations, especially those from Spain, are the most divergent. Pairwise estimates of differentiation point to isolation by distance, and the existence of a latitudinal gradient of divergence was demonstrated using a regression procedure. Similarly, latitudinal differences in haplotype richness and diversity exist, as shown by population permutations (,differentiation through space'). Finally, we measured differentiation by taking into account successive levels of divergence between haplotypes (,differentiation through time'). Genetic differentiation turns out to be much greater when differences between closely related haplotypes are not considered. Further, these results indicate that the phylogeographical structure is essentially due to the relative distribution of the most similar haplotypes. Diversity decreases from south to north, whereas haplotype frequencies change longitudinally. It appears that Hedera survived in Spanish and Balkan refugia during the last ice age. A third refugium must have been present in the Alps or in Italy. During the northward expansion, the decrease in overall diversity was attenuated by some mixing of lineages at intermediate latitudes, resulting in comparatively higher levels of differentiation in the south. [source] Computerised morphometric study of the paraurethral tissue in young and elderly womenNEUROUROLOGY AND URODYNAMICS, Issue 6 2002M. Verelst Abstract Aim. Changes in structural support of the urethra and bladder neck have been proposed to be among the most important factors in the pathogenesis of stress urinary incontinence. In this context, we histologically investigated the paraurethral area in continent women to quantify the relative distribution of connective tissue, smooth muscle, vessels, nerves, and striated muscle. Previously published literature gives only descriptive evaluations of the relative distribution of these tissue components. Methods. We used a computerised morphometric method, which allowed us to estimate the paraurethral tissue distribution in a more objective way. The material was obtained by dissection during autopsy in five premenopausal and five postmenopausal women. Results. Paraurethral tissue consisted of 56% connective tissue (SD, 5%), 30% smooth muscle (SD, 5%), 11% blood vessel (SD, 6%), 2% striated muscle (SD, 3%), and 1% nerves (SD, 1%). We also found that the distribution of different tissue components along the length of the urethra did not differ at a statistically significant level. Furthermore, there was a statistically significant difference in the amount of connective tissue and blood vessels in the postmenopausal women compared with the premenopausal women. Conclusions. The present study shows that the paraurethral area is built of heterogeneous tissue with small changes in its composition along the course of urethra. Increase in connective tissue was found to be the dominating change in the process of ageing. Neurourol. Urodynam. 21:529,533, 2002. © 2002 Wiley-Liss, Inc. [source] Waist-to-hip ratio and adipose tissue distribution: Contribution of subcutaneous adiposityAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2003Mark Daniel The waist-to-hip ratio (WHR) reflects the relative distribution of adipose tissue in the human body. However, whether this is due to the musculoskeletal structures of the waist and hip or the overlying subcutaneous adipose tissue has been disputed. We measured waist and hip girths in 11 male and 11 female cadavers, aged 55,94 years, before and after complete removal of skin and subcutaneous adipose tissue. Girths measured following removal of subcutaneous adipose tissue were termed "waist gx" and "hip gx", and their ratio "WHRx". Masses of regional adipose tissue segments were obtained by complete dissection, and the adipose mass ratios "trunk/arm-plus-leg", "trunk/leg", "internal/arm-plus-leg", and "internal/leg" were derived. As assessed by analysis of variance, WHR accounted for significant (P < 0.05) portions of the variance in all adipose mass ratios; adjustment for internal adipose mass increased the significance of all these relationships (P < 0.005). The ratio WHRx was not related to any ratio of regional adipose masses. Waist girth was related to trunk (P < 0.001) and internal (P < 0.05) adipose masses, and hip girth was related to arm-plus-leg adipose mass (P < 0.0001) and leg adipose mass (P < 0.0001), but waist gx and hip gx were not related to dependent variables. The results indicate that the ability of WHR and waist and hip girths to reflect the regional distribution of adipose tissue in the body is dependent upon the subcutaneous adipose tissue mass of the waist hip area, not its musculoskeletal constituency. Am. J. Hum. Biol. 15:428,432, 2003. © 2003 Wiley-Liss, Inc. [source] Near miss and minor occupational injury: Does it share a common causal pathway with major injury?AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2009Hasanat Alamgir MBA Abstract Background An essential assumption of injury prevention programs is the common cause hypothesis that the causal pathways of near misses and minor injuries are similar to those of major injuries. Methods The rates of near miss, minor injury and major injury of all reported incidents and musculoskeletal incidents (MSIs) were calculated for three health regions using information from a surveillance database and productive hours from payroll data. The relative distribution of individual causes and activities involved in near miss, minor injury and major injury were then compared. Results For all reported incidents, there were significant differences in the relative distribution of causes for near miss, minor, and major injury. However, the relative distribution of causes and activities involved in minor and major MSIs were similar. The top causes and activities involved were the same across near miss, minor, and major injury. Conclusions Finding from this study support the use of near miss and minor injury data as potential outcome measures for injury prevention programs. Am. J. Ind. Med. 52:69,75, 2009. © 2008 Wiley-Liss, Inc. [source] Trends during a half century in relative squamous cell carcinoma distribution by body site in the Swedish population: Support for accumulated sun exposure as the main risk factorTHE JOURNAL OF DERMATOLOGY, Issue 2 2008Henrik DAL ABSTRACT There is a strong relationship between squamous cell carcinoma (SCC) and exposure to ultraviolet radiation in terms of accumulated exposure. In this study, data from the Swedish Cancer Registry are surveyed to discern a reflection of behavioral and societal changes in relative distribution of SCC by body site. Data for the time period 1960,2004, including a total of 66 221 cases (56 669 people) were analyzed by body site for age and gender cohorts. The age-standardized (European population) incidence per 100 000 of SCC in the year 2004 was 30.4 in males and 15.4 in females. In the year 1960, the corresponding incidences were 7.7 and 3.8; that is, SCC has become four times more frequent in Sweden for both sexes during this period. The standardized incidence of SCC increased on all body sites except eyelids (men and women) and ears (women). Head tumors dominated among patients aged 70 years or more and diagnosed 1960,1964. Among patients less than 70 years old at diagnosis in 2000,2004, tumors of the trunk and limbs dominated. A relative increase of tumors of the scalp and neck was observed in all age groups (men), and of tumors of the trunk and upper limbs in all age groups and both sexes except among patients aged more than 90 years of age. In contrast, a relative decrease of tumors on the face (including the ears) was seen in all age groups. The relative increase of SCC of the trunk and upper limbs is a plausible reflection of intentional tanning. [source] Urban-Rural Flows of PhysiciansTHE JOURNAL OF RURAL HEALTH, Issue 4 2007Thomas C. Ricketts PhD ABSTRACT:,Context:Physician supply is anticipated to fall short of national requirements over the next 20 years. Rural areas are likely to lose relatively more physicians. Policy makers must know how to anticipate what changes in distribution are likely to happen to better target policies. Purpose: To determine whether there was a significant flow of physicians from urban to rural areas in recent years when the overall supply of physicians has been considered in balance with needs. Methods: Individual records from merged AMA Physician Masterfiles for 1981, 1986, 1991, 1996, 2001, and 2003 were used to track movements from urban to rural and rural to urban counties. Individual physician locations were tracked over 5-year intervals during the period 1981 to 2001, with an additional assessment for movements in 2001-2003. Findings: Approximately 25% of physicians moved across county boundaries in any given 5-year period but the relative distribution of urban-rural supply remained relatively stable. One third of all physicians remained in the same urban or rural practice location for most of their professional careers. There was a small net movement of physicians from urban to rural areas from 1981 to 2003. Conclusions: The data show a net flow from urban to rural places, suggesting a geographic diffusion of physicians in response to economic forces. However, the small gain in rural areas may also be explained by programs that are intended to counter normal market pressures for urban concentrations of professionals. It is likely that in the face of an overall shortage, rural areas will lose physician supply relative to population. [source] Ultraviolet radiation intensity predicts the relative distribution of dermatomyositis and anti,Mi-2 autoantibodies in womenARTHRITIS & RHEUMATISM, Issue 8 2009Lori A. Love Objective Because studies suggest that ultraviolet (UV) radiation modulates the myositis phenotype and Mi-2 autoantigen expression, we conducted a retrospective investigation to determine whether UV radiation may influence the relative prevalence of dermatomyositis and anti,Mi-2 autoantibodies in the US. Methods We assessed the relationship between surface UV radiation intensity in the state of residence at the time of onset with the relative prevalence of dermatomyositis and myositis autoantibodies in 380 patients with myositis from referral centers in the US. Myositis autoantibodies were detected by validated immunoprecipitation assays. Surface UV radiation intensity was estimated from UV Index data collected by the US National Weather Service. Results UV radiation intensity was associated with the relative proportion of patients with dermatomyositis (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 0.9,5.8) and with the proportion of patients expressing anti,Mi-2 autoantibodies (OR 6.0, 95% CI 1.1,34.1). Modeling of these data showed that these associations were confined to women (OR 3.8, 95% CI 1.3,11.0 and OR 17.3, 95% CI 1.8,162.4, respectively) and suggests that sex influences the effects of UV radiation on autoimmune disorders. Significant associations were not observed in men, nor were UV radiation levels related to the presence of antisynthetase or anti,signal recognition particle autoantibodies. Conclusion This first study of the distribution of myositis phenotypes and UV radiation exposure in the US showed that UV radiation may modulate the clinical and immunologic expression of autoimmune disease in women. Further investigation of the mechanisms by which these effects are produced may provide insights into pathogenesis and suggest therapeutic or preventative strategies. [source] Dust attenuation in starburst galaxies determined by measuring the dependence of the optical color indices on galaxy inclinationASTRONOMISCHE NACHRICHTEN, Issue 7 2010O. Vince Abstract We use optical color indices (colors) from the SDSS database to study the effect of dust in starburst galaxies by mea-suring the dependence of colors on galaxy inclination. Starburst galaxies with ongoing star formation, are rich with metals/dust and are, therefore, an excellent objects for studying the effect of dust in galaxies. They are selected using the [O III], 5007/H, vs. [N II], 6584/H, diagram, that is, the BPT-diagram. We use Kauffmann's empirical demarcation line in the BPT-diagram to exclude galaxies with active galactic nuclei (AGN) from the sample because they have different physical and dust properties from normal galaxies. The sample is divided into bins according to galaxy stellar mass and 4000 Å break (which is a coarse measure of a galaxy star formation history; SFH) and the reddening with inclination is studied as a function of these two physical parameters. Assuming that the dust effect is negligible in the SDSS z -band, we derive the attenuation curves for these galaxies. We fit the attenuation curves with a simple power law and use power law index to interpret the relative distribution of dust and stars in the starburst galaxies (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fifty thousand galaxies at a glanceASTRONOMY & GEOPHYSICS, Issue 3 2002Klaus Meisenheimer Klaus Meisenheimer and Christian Wolf look forward to COMBO-17, a deep sky survey that should make it possible to bridge the gap between matter in the early universe and the pattern of galaxies that we see today. Abstract The COMBO-17 survey should significantly improve our understanding of galaxy evolution during the last 10 billion years in detail, given its multicolour method to determine redshifts and spectral types for 40 000 galaxies within more than a square degree of sky. In addition, mass determination in the supercluster A901/902 should give significant information about the total mass and distribution of dark matter in the universe. In particular, it should be possible to derive new results about the relative distribution of luminous and dark matter. We see this as a significant step in order to answer a decisive question of cosmology: how did the galaxies form from the density peaks in the early universe? [source] Control of the Molecular Weight Distribution of Petroleum Pitches via Dense-Gas ExtractionCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2007E. G. Cervo Abstract Dense-gas extraction (DGE) was used to fractionate an isotropic petroleum pitch (number-average molecular weight Mn,=,516) into oligomeric cuts. A countercurrent-flow packed column was used to effect the separation, with supercritical toluene being used as the dense-gas solvent and commercially available M-50 or A-240 pitch being used as the feed. Isothermal operation at 330, 350, and 380,°C was investigated, as well as operation with a linear positive temperature gradient (+,T), with the bottom of the column at 330 and the top at 380,°C. For isothermal operation, the molecular weight distribution of the bottom products consisted primarily of dimer (Mn,=,508) and trimer (Mn,=,759) species, with pressure changes of as little as 5 bar producing significant changes in their relative distribution, as observed by MALDI mass spectrometry. On the other hand, by operating with a +,T, we could produce a bottom product consisting primarily of trimers and tetramers (Mn,=,997). [source] FTIR microspectroscopy study of composition fluctuations in extruded amylopectin,gelatin blendsBIOPOLYMERS, Issue 4 2001Z. Mousia Abstract The spatial variation in the composition of nonexpanded biopolymer blends prepared by extrusion of mixtures of gelatin with either native or pregelatinized waxy maize starch was studied using a 30-,m aperture FTIR microspectroscopy technique. The ratio of the areas of the "saccharide" bands (953,1180 cm,1) and the amide I and II bands (1483,1750 cm,1) was used to monitor the relative distributions of the two components of the blend. Two calibration methods were used to obtain amylopectin concentration values from the ratios of the IR bands. The results suggested a high degree of heterogeneity in these blends, despite the thorough mixing expected by twin-screw extrusion processing. The concentration fluctuations were greater for the blends produced by extruding gelatin and native waxy maize starch mixtures. This was in agreement with the reduced degree of conversion of the starch granules when extruded in the presence of gelatin. The FTIR 2-dimensional maps obtained suggested that in the blends produced from either native or pregelatinized starch at all concentrations studied (25/75, 50/50, and 75/25 amylopectin/gelatin) the gelatin constituted the continuous phase. The effect of the spatial resolution on the FTIR microspectroscopy results was considered and the proposed interpretation was verified by the use of polarized light microscopy and FTIR microspectroscopy acquired at higher spatial resolution (10 ,m). © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 208,218, 2001 [source] | |||||||||||||||||||||||||||||||||||||