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Boundary Line (boundary + line)
Selected AbstractsTemporal dynamics and nestedness of an oceanic island bird faunaGLOBAL ECOLOGY, Issue 4 2006Ermias T. Azeria ABSTRACT Aim, To examine temporal variation in nestedness and whether nestedness patterns predict colonization, extinction and turnover across islands and species. Location, Dahlak Archipelago, Red Sea. Method, The distributions of land birds on 17 islands were recorded in two periods 30 years apart. Species and islands were reordered in the Nestedness Temperature Calculator, software for assessing degrees of nestedness in communities. The occupancy probability of each cell, i.e. species,island combinations, was calculated in the nested matrix and an extinction curve (boundary line) was specified. We tested whether historical and current nested ranks of species and islands were correlated, whether there was a relationship between occupancy probability (based on the historical data) and number of extinctions or colonizations (regression analyses) and whether the boundary line could predict extinctions and colonizations (chi-square analyses). Results, Historical and current nested ranks of islands and species were correlated but changes in occupancy patterns were common, particularly among bird species with intermediate incidence. Extinction and turnover of species were higher for small than large islands, and colonization was negatively related to isolation. As expected, colonizations were more frequent above than below the boundary line. Probability of extinction was highest at intermediate occupancy probability, giving a quadratic relationship between extinction and occupancy probability. Species turnover was related to the historical nested ranks of islands. Colonization was related negatively while extinction and occupancy turnover were related quadratically to historical nested ranks of species. Main conclusions, Some patterns of the temporal dynamics agreed with expectations from nested patterns. However, the accuracy of the predictions may be confounded by regional dynamics and distributions of idiosyncratic, resource-limited species. It is therefore necessary to combine nestedness analysis with adequate knowledge of the causal factors and ecology of targeted species to gain insight into the temporal dynamics of assemblages and for nestedness analyses to be helpful in conservation planning. [source] Landscapes of the Law: Injury, Remedy, and Social Change in ThailandLAW & SOCIETY REVIEW, Issue 1 2009David M. Engel Sociolegal theorists since Weber have postulated that state law operates by interacting with and responding to nonstate legal orders. This article, examining conceptions of injury and compensation in Thailand, analyzes two ways of mapping law onto the landscape. The first is associated with state law and legal institutions established at the turn of the twentieth century. The state legal system imagines space from the outside in, drawing a boundary line and applying law uniformly throughout the jurisdiction it has enclosed. A second type of mapping, which has been more familiar over the centuries to ordinary Thai people, imagines space from the inside out. Nonstate legal orders are associated with sacred centers and radiate outward, diminishing in intensity and effectiveness with distance. This article, based on extensive interviews with injured persons and other actors and observers in northern Thailand, examines the interconnections between these two ways of imagining the landscape of law. It suggests that recent transformations of Thai society have rendered ineffective the norms and procedures associated with the law of sacred centers. Consequently, state law no longer interacts with or responds to nonstate law and surprisingly plays a diminished role in the lives of ordinary people who suffer injuries. [source] On testing biological data for the presence of a boundaryANNALS OF APPLIED BIOLOGY, Issue 2 2006A.E. Milne Abstract Under the boundary line model for a biological data set, where one variable is a biological response (e.g. crop yield) to an independent variable (e.g. available water content of the soil), we interpret the upper (or lower) boundary on a plot of the dependent variable (ordinate) against the independent variable (abscissa) as representing the maximum (or minimum) possible response for a given value of the independent variable. This concept has been widely used in soil science, agronomy and plant physiology; but it has been subject to criticism. In particular, no methods that are used to analyse the boundary line quantify the evidence that the envelope of the plot represents a boundary (in the sense of some limiting response to the independent variable) rather than simply being a fringe of extreme values of no intrinsic biological interest. In this article, we present a novel procedure that tests a data set for evidence of a boundary by considering its statistical properties in the region of the proposed boundary. The method is demonstrated using both simulated and real data sets. [source] New perspectives of optical coherrence tomography in diagnosis and follow-up of macular holesACTA OPHTHALMOLOGICA, Issue 2009SA KABANAROU Purpose To compare Time Domain (TD) with Spectral Domain (SD) OCT for imaging macular holes, identify retinal pathology and correlate anatomical morphology after surgical intervention for hole closure with visual outcome. Methods 34 eyes of 34 patients with idiopathic macular holes stage II- IV were included in this study. Comparative studies were performed with both SD OCT (Heidelberg, Germany) and TD OCT (Stratus) using standard scanning protocols of 6 radial 6-mm scans through the fovea. All patients underwent a standard three port- pars plana vitrectomy. Postoperatively, all patients were evaluated using both OCTs. ETDRS visual acuities were recorded pre- and post-operatively. Results In general TD and SD OCTs showed comparable images of macular holes. However, the boundary line between the inner and outer segments of the photoreceptors was better imaged with the SD OCT preoperatively and postoperatively. Poor visual acuity postoperatively was measured mainly in cases with morphological disruption in this boundary line despite hole closure. Conclusion SD OCT imaging enhances the visualization of retinal anatomy in macular holes relative to TD OCT. [source] COLLAPSE-SUBMERGENCE METHOD: SIMPLE COLONOSCOPIC TECHNIQUE COMBINING WATER INFUSION WITH COMPLETE AIR REMOVAL FROM THE RECTOSIGMOID COLONDIGESTIVE ENDOSCOPY, Issue 1 2007Takeshi Mizukami Colonoscopy is a difficult examination to conduct for inexperienced examiners. In an attempt to improve the view, there is often a tendency to overinsufflate air, which causes elongation or acute angulations of the colon and makes passage of the scope difficult. Sakai et al. were the first to describe a simple colonoscopic technique using water infusion instead of air insufflation. We have modified this technique to simplify the procedure further by combining water infusion using disposable syringes with complete air suction from the rectum to the descending colon. With the resultant elimination of the boundary lines between water and air, a good view of the lumen is obtained though the transparent water. With the patient in the left lateral position, this procedure allows the water to flow straight down into the descending colon through the ,collapsed' lumen, and the scope to be easily negotiated through the straightened recto-sigmoid colon and sigmoid-descending colon junction with minimum discomfort. Measurements of the patients' abdominal circumference during colonoscopy showed that colonic distension hardly occurred. Under supervision by the author, six complete novices were allowed to insert the colonoscope within 10 min by this method for one patient per week, as long as the patients did not complain of pain. The average trial number for the first cecal intubation within 10 min was 3.3, and the average success rate during the first 3 months was 58.6%. We believe that this ,collapse-submergence method' is easy to master, even for inexperienced examiners. [source] A note on hinge-free topology design using the special triangulation of design elementsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2005Jae Eun Kim Abstract Hinges, the unrepeated checkerboard cells, may appear in the topology optimization using low-order finite elements, especially for compliant mechanism design. Existing hinge-controlling methods are based on the rectangular element discretization, so slant or curved boundary lines may not be represented satisfactorily. To avoid hinge formation and to represent curved boundary lines better, we consider a macro-design element method which subdivides the design element into eight triangular finite elements; the finite element calculation is carried out with triangular elements, but the design variables are defined at the nodes defining rectangular macro-design elements. For hinge-free results, different stiffness interpolations are suggested depending on whether the triangular element belongs to a master group or a slave group. The performance of the proposed method was checked with compliant mechanism design problems from the viewpoint of hinge suppression and the possibility of generating slant boundary lines. Copyright © 2005 John Wiley & Sons, Ltd. [source] Biogeography of the livebearing fish Poecilia gillii in Costa Rica: are phylogeographical breaks congruent with fish community boundaries?MOLECULAR ECOLOGY, Issue 19 2009JARED B. LEE Abstract One of the original goals of phylogeography was to use genetic data to identify historical events that might contribute to breaks among communities. In this study, we examine the phylogeography of a common livebearing fish (Poecilia gillii) from Costa Rica. Our goal was to determine if phylogeographical breaks in this species were congruent with previously defined boundaries among four fish community provinces. We hypothesized that if abiotic factors influence both community boundaries and genetic structuring in P. gillii then we might find four clades within our focal species that were geographically separated along community boundary lines. Similarly, we expected to find most of the genetic variation in P. gillii partitioned among these four geographical regions. We generated DNA sequence data (mitochondrial cytochrome b and nuclear S7 small ribosomal subunit) for 260 individuals from 42 populations distributed across Costa Rica. We analysed these data using phylogenetic (parsimony and likelihood) and coalescent approaches to estimate phylogenetic relationships among haplotypes, patterns of gene flow and effective population size. Contrary to our expectations, we did not find four monophyletic groups that mapped cleanly to our geographical community provinces. However, one of our clades was restricted to a single province, suggesting that common earth history events could be responsible for both genetic structuring in P. gillii and fish community composition in this area. However, our results show a complex pattern of gene flow throughout other regions in Costa Rica where genetic structuring is not predicted by community province boundaries. [source] | |||||||||||||