108 research outputs found

    Comunicación Bilateral de los Nervios Músculocutáneo y Mediano. Aspectos Morfológicos e Importancia Clínica

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    Cerda, A (Cerda, Aladino). Univ Talca, Talca, ChileCommunication of the musculocutaneous and median nerves of the brachial plexus is common and is important in the evaluation of trauma and surgical procedures in axillary and brachial regions. This paper presents a case in which during a routine dissection of upper limb the presence of bilateral communication between musculocutaneous and medium nerves was observed. Trajectory of communicating branches was described, relation and morphometry was discussed with regard to prevalence and clinical significance of these communications

    Novel techniques for location-cloaked applications

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    Location cloaking has been shown to be cost-effective in mitigating location privacy and safety risks. This strategy, however, has significant impact on the applications that rely on location information. They may suffer efficiency loss; some may not even work with reduced location resolution. This research investigates two problems. 1) How to process location-cloaked queries. Processing such queries incurs significant more workload for both server and client. While the server needs to retrieve more query results and transmit them to the client, the client downloading these results wastes its battery power because most of them are useless. To address these problems, we propose a suite of novel techniques including query decomposition, scheduling, and personalized air indexing. These techniques are integrated into a single unified platform that is capable of handling various types of queries. 2) How a node V can verify whether or not another node P indeed locates in a cloaking region it claims. This problem is challenging due to the fact that the process of location verification may allow V to refine P\u27s location within the region. We identify two types of attacks, transmission coverage attack and distance bounding attack. In the former, V refines a cloaking region by adjusting its transmission range to partially overlap with the region, whereas in the latter, by measuring the round trip time of its communication with P. We present two corresponding counter strategies, and built on top of them, propose a novel technique that allows P to participate in location verification while providing a certain level of guarantee that its cloaking region will not be refined during the process

    Managing continuous k-nearest neighbor queries in mobile peer-to-peer networks

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    A continuous k nearest neighbor (CKNN) query retrieves the set of k mobile nodes that are nearest to a query point, and provides real-time updates whenever this set of nodes changes. A CKNN query can be either stationary or mobile, depending on the mobility of its query point. Efficient processing of CKNN queries is essential to many applications, yet most existing techniques assume a centralized system, where one or more central servers are used for query management. In this thesis, we assume a fully distributed mobile peer-to-peer system, where mobile nodes are the only computing devices, and present a unified platform for efficient processing of both stationary and mobile CKNN queries. For each query, our technique computes a set of safe boundaries and lets mobile nodes monitor their movement with respect to these boundaries. We show that the result of a query does not change unless a node crosses over a safe boundary. As such, our technique requires a query to be re-evaluated only when there is a crossing event, thus minimizing the cost of query evaluation. For performance study, we model the communication cost incurred in query processing with a detailed mathematical analysis and verify its accuracy using simulation. Our extensive study shows that the proposed technique is able to provide real-time and accurate query results with a reasonable cost

    Factorizing Kernel Operators

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    Consider an operator T : X--->Y between Banach function spaces having adequate order continuity and Fatou properties. Assume that T can be factorized through a Banach space as T =SR, where R and the adjoint of S are p-th power and q-th power factorable, respectively. Then a canonical factorization scheme can be given for T. We show that it provides a tool for analyzing T that becomes specially useful for the case of kernel operators. In particular, we show that this square factorization scheme for T is equivalent to some inequalities for the bilinear form defined by T. Kernel operators are studied from this point of view.Support of the Ministerio de Economia y Competitividad under project # MTM2012-36740-C02-02 (Spain) is gratefully acknowledged.Galdames, O.; Sánchez Pérez, EA. (2013). Factorizing Kernel Operators. Integral Equations and Operator Theory. 75(1):13-29. https://doi.org/10.1007/s00020-012-2019-zS1329751Bennett C., Sharpley R.: Interpolation of Operators. Academic Press, Boston (1988)Calabuig J.M., Delgado O., Sánchez-Pérez E.A.: Factorizing operators on Banach function spaces through spaces of multiplication operators. J. Math. Anal. Appl. 364, 88–103 (2010)Defant A.: Variants of the Maurey-Rosenthal theorem for quasi Köthe function spaces. Positivity 5, 153–175 (2001)Defant A., Sánchez Pérez E.A.: Maurey-Rosenthal factorization of positive operators and convexity. J. Math. Anal. Appl. 297, 771–790 (2004)Diestel, J., Uhl, J.J.: Vector Measures. Mathematical Surveys, vol. 15. American Mathematical Society, Providence (1977)Fernández A., Mayoral F., Naranjo F., Sáez C., Sánchez-Pérez E.A.: Spaces of integrable functions with respect to a vector measure and factorizations through L p and Hilbert spaces. J. Math. Anal. Appl. 330, 1249–1263 (2007)Galdames O., Sánchez Pérez E.A.: Optimal range theorems for operators with p-th power factorable adjoints. Banach J. Math. Anal. 6(1), 63–71 (2012)Lindenstrauss J., Tzafriri L.: Classical Banach Spaces II. Springer, Berlin (1979)Okada, S., Ricker, W.J., Sánchez Pérez, E.A.: Optimal Domain and Integral Extension of Operators acting in Function Spaces. Operator Theory: Adv. Appl., vol. 180. Birkhäuser, Basel (2008)Zaanen, A.C.: Integration, 2nd revised edn. North Holland, Amsterdam; Interscience, New York (1967

    Evaluación del Perfil Nasal Mediante Morfometría Geométrica en una Muestra de Población Chilena. Implicancias Clínicas y Forenses

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    Schilling, A (Schilling, Alejandro). Univ Talca, Talca, ChileThe search of morphological patterns of nasal profile using traditional morphometrics has been the goal of several studies aiming to orient therapeutical planning and forensic techniques such as facial reconstruction. The present study aims to find and describe such patterns with geometric morphometric tools in a sample of Chilean population with geometric morphometric tools. We used the lateral X-rays of 156 individuals (men and women) and 14 landmarks in bone and soft tissues. Procrustes analysis was performed followed by principal component analysis to assess general shape variation, regression of shape components against centroid size to study to allometric effect and discriminant analysis by sex with cross-validation test. Our results show the lack of shape patterns, and that the size, followed by sex, explains within a limited scope the shape changes which suggests the presence of uncontrolled variables and a high effect of inter-individual variation. In general terms bigger profiles, more frequent in men, show a lower Pronasal point, a more prominent nasal dorsum with a thicker layer of soft tissue, and a vertically expanded upper lip. We suggest the reassessment of the importance of individual aesthetic evaluation for clinical purposes, and recommend caution in concluding results based on forensic reconstruction technique

    A model for a collaborative recommender system for multimedia learning material

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    Abstract. In a cluster of many servers containing heterogeneous multimedia learning material and serving users with different backgrounds (e.g. language, interests, previous knowledge, hardware and connectivity) it may be difficult for the learners to find a piece of material which fit their needs. This is the case of the COLDEX project. Recommender systems have been used to help people sift through all the available information to find that most valuable to them. We propose a recommender system, which suggest multimedia learning material based on the learner's background preferences as well as the available hardware and software that he/she has.

    Sex Determination by Observation of Barr Body in Teeth Subjected to High Temperatures

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    Galdames, IS (reprint author), Univ Talca, Ave Lircay S-N Oficina 104, Valparaiso, Chile.Sex determination is one of the keys in the identification process. A useful histological method for sex determination is the observation of Barr chromatin or Barr body. This study determines the effect of high temperatures on the diagnostic performance of the Barr chromatin observation on teeth. Were used 50 healthy teeth from 25 male and 25 female individuals aged between 14 and 44 years. The teeth were divided into 5 groups (each group with 5 female and 5 male teeth) and were exposed to controlled temperatures of 200, 400, 600, 800, and 1000 degrees C for 5 minutes. The coronal pulp was obtained and the tissue was processed and stained with hematoxylin-eosin. Four histological slides of male and 4 of female individuals were randomly selected, for each temperature level, which were observed by conventional microscopy at 100X magnification, each showing 50 cells per plate. The presence of 1 cell with visible sex chromatin was considered positive for females. It was only possible to evaluate the samples from groups subjected to 200 and 400 degrees C. In the groups analyzed, the test showed 100% accuracy. The average number of cells found to be positive Barr chromatin was 15 (SD 3.9) at 200 degrees C and 11 (SD 2.8) at 400 degrees C. Hence, it was possible to detect the sex at these temperatures by observing chromatin of the Barr body in dental pulp

    Differences in the fly-load of Haematobia irritans (Diptera: Muscidae) on cattle is modified by endophyte infection of pastures

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    Background: The horn fly, Haematobia irritans, is an obligate bloodsucking ectoparasite of pastured cattle and is a major pest of livestock production in North and South America and Europe. In this study, we investigated the potential to use cattle pastures, infected with non-toxic, "friendly" fungal-endophyte-infected (E+) tall fescue, Festuca arundinacea Schreb., as a strategy for reducing horn fly loads in cattle, and to evaluate the possible bioinsecticide effect on horn fly larvae. Results: When cattle grazed in E+ tall fescue, a decrease in fly-load was observed, compared with other pastures (endophyte-free (E-) pastures). The infestation of horn fly load decreased according to an increase in the percentage of endophyte present in the different pastures (0 to 100%). Moreover, two groups of animals with significant differences in the fly-load (high and low fly-load) in the same herd were observed (P < 0.05). Additionally, it was possible to determine a bioinsecticide effect of cattle dung, upon horn fly larvae (80%), from animals fed E+ tall fescue. Conclusions: These results constitute the first report on the potential for exploiting pasture management for controlling 1) horn fly-loads on cattle and 2) the normal development of horn fly larvae. In conclusion, this information provides preliminary understanding of the role of cattle pasture diet management for controlling horn fliesas part of an integrated pest management strategy for this major pest of farmed livestock

    Development of new remediation technologies for contaminated soils based on the application of zero-valent iron nanoparticles and bioremediation with compost

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    This study aimed to develop new techniques for the remediation of contaminated soils based on the applicationof zero-valent iron nanoparticles (nZVI) and bioremediation with compost from organic wastesand a mixed technique of both. An assessment of the effectiveness of remediation in two soils contaminatedwith hydrocarbons and heavy metals was carried out, with the aim of looking for positive synergiesby combining the two techniques, and demonstrating their viability on an industrial scale. The applicationof nZVI for in situ immobilization of As and Cr in two different soils (Soil I from a contaminatedindustrial site and Soil II, contaminated artificially) showed a decrease in the concentration of As in SoilI and Soil II, as well as a decrease in Cr concentration for Soil I and Soil II in the leachate of both soils.The addition of compost and nanoparticles under uncontrolled environmental conditions in biopiles wasable to produce a decrease in the concentration of aliphatic hydrocarbons of up to 60% in the two soils.Especially, degradation and transformation of longer chains occurred. A significant reduction of ecotoxicitywas observed throughout the process in the biopile of soil II, not reaching the LC50 even with 100%of the sample after the treatment, in both earthworm and seeds growth tests

    Variations of the Vocal Fold Epithelium in a Menopause Induced Model

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    During menopause, changes occur in the laryngeal structures that have implications for the voice. The purpose of this study was to determine the effect of induced menopause on the morphological parameters of the vocal fold mucosa in rats. Ten adult female Sprague-Dawley rats were used as samples and divided into two groups: 5 were surgically oophorectomized (OVX), and 5 underwent a surgical procedure similar to oophorectomy but without removal of the ovaries (SHAM). After 30 days surgery, the characteristics of the epithelium that forms the vocal fold mucosa in terms of cellular arrangement and organization of the epithelium were observed. Through the Morphometrics XS software, the epithelial height and the number and density of cellular layers were determined. Our results indicate that there were alterations in the number of cell layers that constitute the epithelium, as well as features, such as cellular cohesion and increased extracellular matrix. The number of cell layers was significantly higher (p<0.01) in the SHAM group with 6.66 (SD 1.07), whereas in the OVX was 3.2 (SD 0.83). The average thickness of the epithelium was 534.71 mm (SD 119.89), whereas in the SHAM group was 486.84 mm (SD 82.95); these differences were not statistically significant (p = 0.112). Changes in the characteristics of the epithelium covering the vocal folds can be related to clinical abnormalities, such as reduced voice quality and degeneration of the vocal folds in postmenopausal women
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