903 research outputs found

    Feed-forward volume rendering algorithm for moderately parallel MIMD machines

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    Algorithms for direct volume rendering on parallel and vector processors are investigated. Volumes are transformed efficiently on parallel processors by dividing the data into slices and beams of voxels. Equal sized sets of slices along one axis are distributed to processors. Parallelism is achieved at two levels. Because each slice can be transformed independently of others, processors transform their assigned slices with no communication, thus providing maximum possible parallelism at the first level. Within each slice, consecutive beams are incrementally transformed using coherency in the transformation computation. Also, coherency across slices can be exploited to further enhance performance. This coherency yields the second level of parallelism through the use of the vector processing or pipelining. Other ongoing efforts include investigations into image reconstruction techniques, load balancing strategies, and improving performance

    Ancient technology and punctuated change: Detecting the emergence of the Edomite Kingdom in the Southern Levant.

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    While the punctuated equilibrium model has been employed in paleontological and archaeological research, it has rarely been applied for technological and social evolution in the Holocene. Using metallurgical technologies from the Wadi Arabah (Jordan/Israel) as a case study, we demonstrate a gradual technological development (13th-10th c. BCE) followed by a human agency-triggered punctuated "leap" (late-10th c. BCE) simultaneously across the entire region (an area of ~2000 km2). Here, we present an unparalleled, diachronic archaeometallurgical dataset focusing on elemental analysis of dozens of well-dated slag samples. Based on the results, we suggest punctuated equilibrium provides an innovative theoretical model for exploring ancient technological changes in relation to larger sociopolitical conditions-in the case at hand the emergence of biblical Edom-, exemplifying its potential for more general cross-cultural applications

    Noisy Beeping Networks

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    We introduce noisy beeping networks, where nodes have limited communication capabilities, namely, they can only emit energy or sense the channel for energy. Furthermore, imperfections may cause devices to malfunction with some fixed probability when sensing the channel, which amounts to deducing a noisy received transmission. Such noisy networks have implications for ultra-lightweight sensor networks and biological systems. We show how to compute tasks in a noise-resilient manner over noisy beeping networks of arbitrary structure. In particular, we transform any algorithm that assumes a noiseless beeping network (of size nn) into a noise-resilient version while incurring a multiplicative overhead of only O(logn)O(\log n) in its round complexity, with high probability. We show that our coding is optimal for some tasks, such as node-coloring of a clique. We further show how to simulate a large family of algorithms designed for distributed networks in the CONGEST(BB) model over a noisy beeping network. The simulation succeeds with high probability and incurs an asymptotic multiplicative overhead of O(BΔmin(n,Δ2))O(B\cdot \Delta \cdot \min(n,\Delta^2)) in the round complexity, where Δ\Delta is the maximal degree of the network. The overhead is tight for certain graphs, e.g., a clique. Further, this simulation implies a constant overhead coding for constant-degree networks

    Importancia del uso de Estrategias Lúdicas que implementa la Docente durante el proceso de Enseñanza y Aprendizaje para potenciar al máximo las habilidades adaptativas en los Estudiantes que presenta Deficiencia Cognitiva del Primer Ciclo del Centro de Atención específica el Güís, durante el II Semestre del Año Lectivo 2016

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    La presente investigación se realizó en el centro de atención Especifica El Güis de Managua, Nicaragua en el aula de primer ciclo, con el propósito de conocer cuáles son las actividades lúdicas que utiliza la docente para favorecer el desarrollo de las habilidades adaptativas en los estudiantes que presentan deficiencia cognitiva. Esta es una investigación de carácter cualitativo, donde se realizó un estudio de caso, en el cual se utilizó la entrevista como instrumento para la recolección de información relevante, así también guías de observación y visitas al aula donde se desarrolló el escenario pedagógico y, por otro lado, se revisaron diferentes referencias bibliográficas. Según Vygotsky (1993) expresa que las actividades lúdicas están presentes en todos los espacios de la vida de los seres humanos, permitiendo aprender e interactuar con el mundo y las cosas, reconocer y recrear su mundo y de forma muy particular las actividades lúdicas ocupan un lugar fundamental en el proceso de enseñanza aprendizaje, en términos educativos. Los resultados de la presente investigación muestran que la docente no está haciendo uso de estrategias lúdicas en el proceso de enseñanza aprendizaje para potenciar las habilidades adaptativas de los estudiantes que presentan deficiencia cognitiva y a pesar de ser una herramienta tan vital la docente le ha restado importancia . Por lo antes expuesto se recomienda a la docente documentarse a cerca de la importancia de realizar actividades lúdicas y de la selección pertinente de dichas estrategias, tomando en cuenta las particularidades y necesidades educativas de sus estudiantes y luego sean incorporadas en la planificación didáctica e implementadas en el salón de clase para favorecer el desarrollo de habilidades adaptativas de los estudiantes que presentan deficiencia cognitiv

    Ultrasound-guided Transvaginal Aspiration in the Management of Actinomyces Pelvic Abscess

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    Background: Increasing reports of intrauterine device (IUD)-related abdominopelvic actinomycosis have been described recently. Surgical therapy has been the usual treatment when tubo-ovarian abscess is identified

    Editorial: Editors' showcase: obstetrics and gynecology

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    Decidual Macrophages Are Significantly Increased in Spontaneous Miscarriages and Over-Express FasL

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    Decidual macrophages (DM) are the second most abundant population in the fetal-maternal interface. Their role has been so far identified as being local immuno-modulators favoring the maternal tolerance to the fetus. Herein we investigated tissue samples from 11 cases of spontaneous miscarriages and from 9 cases of elective terminations of pregnancy. Using immunohistochemistry and dual immunofluorescence we have demonstrated that in spontaneous miscarriages the DM are significantly increased. Additionally, we noted a significant up-regulation of macrophage FasL expression. Our results further support a dual role for DM during pregnancy and miscarriages. We hypothesize that the baseline DM population in normal pregnancy is in line with an M2 phenotype supporting the ongoing gestation. In contrast, during spontaneous miscarriages, the increased FasL-expressing population could be a part of an M1 phenotype participating in Fas/FasL-related apoptosis. Our results highlight a new aspect of macrophage biology in pregnancy physiology and pathophysiology. Further studies with larger samples are needed to verify the current results and evaluate their clinical impact

    Inhibitory NK Receptor Recognition of HLA-G: Regulation by Contact Residues and by Cell Specific Expression at the Fetal-Maternal Interface

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    The non-classical HLA-G protein is distinguished from the classical MHC class I molecules by its expression pattern, low polymorphism and its ability to form complexes on the cell surface. The special role of HLA-G in the maternal-fetal interface has been attributed to its ability to interact with specific receptors found on maternal immune cells. However this interaction is restricted to a limited number of receptors. In this study we elucidate the reason for this phenomenon by comparing the specific contact residues responsible for MHC-KIR interactions. This alignment revealed a marked difference between the HLA-G molecule and other MHC class I molecules. By mutating these residues to the equivalent classical MHC residues, the HLA-G molecule regained an ability of interacting with KIR inhibitory receptors found on NK cells derived either from peripheral blood or from the decidua. Functional NK killing assays further substantiated the binding results. Furthermore, double immunofluorescent staining of placental sections revealed that while the conformed form of HLA-G was expressed in all extravillous trophoblasts, the free heavy chain form of HLA-G was expressed in more distal cells of the column, the invasion front. Overall we suggest that HLA-G protein evolved to interact with only some of the NK inhibitory receptors thus allowing a control of inhibition, while permitting appropriate NK cell cytokine and growth factor production necessary for a viable maternal fetal interface

    Eleven fetal echocardiographic planes using 4-dimensional ultrasound with spatio-temporal image correlation (STIC): a logical approach to fetal heart volume analysis

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    <p>Abstract</p> <p>Background</p> <p>Theoretically, a cross-sectional image of any cardiac planes can be obtained from a STIC fetal heart volume dataset. We described a method to display 11 fetal echocardiographic planes from STIC volumes.</p> <p>Methods</p> <p>Fetal heart volume datasets were acquired by transverse acquisition from 200 normal fetuses at 15 to 40 weeks of gestation. Analysis of the volume datasets using the described technique to display 11 echocardiographic planes in the multiplanar display mode were performed offline.</p> <p>Results</p> <p>Volume datasets from 18 fetuses were excluded due to poor image resolution. The mean visualization rates for all echocardiographic planes at 15-17, 18-22, 23-27, 28-32 and 33-40 weeks of gestation fetuses were 85.6% (range 45.2-96.8%, N = 31), 92.9% (range 64.0-100%, N = 64), 93.4% (range 51.4-100%, N = 37), 88.7%(range 54.5-100%, N = 33) and 81.8% (range 23.5-100%, N = 17) respectively.</p> <p>Conclusions</p> <p>Overall, the applied technique can favorably display the pertinent echocardiographic planes. Description of the presented method provides a logical approach to explore the fetal heart volumes.</p
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