2,332 research outputs found

    Guidelines For Pursuing and Revealing Data Abstractions

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    Many data abstraction types, such as networks or set relationships, remain unfamiliar to data workers beyond the visualization research community. We conduct a survey and series of interviews about how people describe their data, either directly or indirectly. We refer to the latter as latent data abstractions. We conduct a Grounded Theory analysis that (1) interprets the extent to which latent data abstractions exist, (2) reveals the far-reaching effects that the interventionist pursuit of such abstractions can have on data workers, (3) describes why and when data workers may resist such explorations, and (4) suggests how to take advantage of opportunities and mitigate risks through transparency about visualization research perspectives and agendas. We then use the themes and codes discovered in the Grounded Theory analysis to develop guidelines for data abstraction in visualization projects. To continue the discussion, we make our dataset open along with a visual interface for further exploration

    An examination of Maya metallurgy, 1150 to 1544 A.D.

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    Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1990.Includes bibliographical references (leaves 65-66).by Katherine E. Williams.B.S

    An XMM-Newton and Chandra Study of the Starburst Galaxy IC 10

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    We present an X-ray study of our nearest starburst galaxy IC 10, based on XMM-Newton and Chandra observations. A list of 73 XMM-Newton and 28 Chandra detections of point-like X-ray sources in the field is provided; a substantial fraction of them are likely stellar objects in the Milky Way due to the low Galactic latitude location of IC 10. The brightest source in the IC 10 field, X-1, shows a large variation by a factor of up to 6\sim 6 on time scales during the XMM-Newton observation. The X-ray spectra of the source indicate the presence of a multi-color blackbody accretion disk with an inner disk temperature T_{in} \approx 1.1 keV. These results are consistent with the interpretation of the source as a stellar mass black hole, probably accreting from a Wolf-Rayet star companion. We infer the mass of this black hole to be about 4 Msun if it is not spinning, or a factor of up to about 6 higher if there is significant spinning. We also detect an apparent diffuse soft X-ray emission component of IC 10. An effective method is devised to remove the X-ray CCD-readout streaks of X-1 that strongly affect the study of the diffuse component in the XMM-Newton and Chandra observations. We find that the diffuse X-ray morphology is oriented along the optical body of the galaxy and is chiefly associated with starburst regions. The diffuse component can be characterized by an optically thin thermal plasma with a mean temperature of 4×106\sim 4 \times 10^6 K and a 0.5-2 keV luminosity of 8×1037ergs1\sim 8 \times 10^{37} {\rm erg s^{-1}}, representing only a small fraction of the expected mechanical energy inputs from massive stars in the galaxy. There is evidence that the hot gas is driving outflows from the starburst regions; therefore, the bulk of the energy inputs may be released in a galactic wind.Comment: 30 pages, accepted for publication in MNRA

    American Indian painters of Oklahoma : artistic negotiation in the twentieth century.

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    This work discusses the emergence of easel painting as an art form in Oklahoma American Indian communities and the commoditization of American Indian art during the twentieth century. The lives and art of five Muscogee Creek painters working during the twentieth century, Acee Blue Eagle, Solomon McCombs, Fred Beaver, Joan Hill and Enoch Kelly Haney, are documented and discussed. By examining each artist’s works, their personal biographies and changes in their artistic style, the author demonstrates the multiple ways in which artists respond to fluctuations within the market for American Indian art

    Clonal amplification of Fasciola hepatica in Galba truncatula: within and between isolate variation of triclabendazole-susceptible and -resistant clones

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    Background: Fasciola hepatica is of worldwide significance, impacting on the health, welfare and productivity of livestock and regarded by WHO as a re-emerging zoonosis. Triclabendazole (TCBZ), the drug of choice for controlling acute fasciolosis in livestock, is also the drug used to treat human infections. However TCBZ-resistance is now considered a major threat to the effective control of F. hepatica. It has yet to be demonstrated whether F. hepatica undergoes a genetic clonal expansion in the snail intermediate host, Galba truncatula, and to what extent amplification of genotypes within the snail facilitates accumulation of drug resistant parasites. Little is known about genotypic and phenotypic variation within and between F. hepatica isolates. Results: Six clonal isolates of F. hepatica (3× triclabendazole-resistant, TCBZ-R and 3× triclabendazole-susceptible, TCBZ-S) were generated. Snails infected with one miracidium started to shed cercariae 42–56 days post-infection and shed repeatedly up to a maximum of 11 times. A maximum of 884 cercariae were shed by one clonally-infected snail (FhLivS1) at a single time point, with > 3000 clonal metacercariae shed over its lifetime. Following experimental infection all 12 sheep were FEC positive at the time of TCBZ treatment. Sheep infected with one of three putative TCBZ-S clones and treated with TCBZ had no parasites in the liver at post-mortem, whilst sheep each infected with putative TCBZ-R isolates had 35–165 adult fluke at post-mortem, despite TCBZ treatment. All six untreated control animals had between 15–127 parasites. A single multi-locus genotype was reported for every fluke from each of the six clonal isolates. Adult F. hepatica showed considerable variation in weight, ranging from 20–280 mg, with variation in weight evident within and amongst clonal isolates. Conclusions: A genetic clonal expansion occurs within G. truncatula, highlighting the potential for amplification of drug resistant genotypes of F. hepatica. Variation in the weight of parasites within and between clonal isolates and when comparing isolates that are either susceptible or resistant to TCBZ represent inherent variation in liver fluke and cannot be attributed to their resistance or susceptibility traits

    “Great Job Cleaning Your Plate Today!” Determinants of Child-Care Providers’ Use of Controlling Feeding Practices: An Exploratory Examination

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    Background National early childhood obesity prevention policies recommend that child-care providers avoid controlling feeding practices (CFP) (e.g., pressure-to-eat, food as reward, and praising children for cleaning their plates) with children to prevent unhealthy child eating behaviors and childhood obesity. However, evidence suggests that providers frequently use CFP during mealtimes. Objective Using the Academy of Nutrition and Dietetics (2011) benchmarks for nutrition in child care as a framework, researchers assessed child-care providers’ perspectives regarding their use of mealtime CFP with young children (aged 2 to 5 years). Design Using a qualitative design, individual, face-to-face, semi-structured interviews were conducted with providers until saturation was reached. Participants/setting Providers were selected using maximum variation purposive sampling from varying child-care contexts (Head Start, Child and Adult Care Food Program [CACFP] e-funded centers, non-CACFP programs). All providers were employed full-time in Head Start or state-licensed center-based child-care programs, cared for children (aged 2 to 5 years), and were directly responsible for serving meals and snacks. Main outcome measure Child-care providers’ perspectives regarding CFP. Statistical analyses performed Thematic analysis using NVivo (version 9, 2010, QSR International Pty Ltd) to derive themes. Results Providers’ perspectives showed barriers, motivators, and facilitators regarding their use of mealtime CFP. Providers reported barriers to avoiding CFP such as CFP were effective for encouraging desired behaviors, misconceptions that providers were encouraging but not controlling children’s eating, and fear of parents’ negative reaction if their child did not eat. Providers who did not practice CFP were motivated to avoid CFP because they were unnecessary for encouraging children to eat, and they resulted in negative child outcomes and obesity. Facilitators as an alternative to CFP included practicing healthful feeding practices such as role modeling, peer modeling, and sensory exploration of foods. Conclusions Training providers about negative child outcomes associated with CFP, children’s ability to self-regulate energy intake, and differentiating between controlling and healthful feeding strategies may help providers to avoid CFP

    “Great Job Cleaning Your Plate Today!” Determinants of Child-Care Providers’ Use of Controlling Feeding Practices: An Exploratory Examination

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    Background National early childhood obesity prevention policies recommend that child-care providers avoid controlling feeding practices (CFP) (e.g., pressure-to-eat, food as reward, and praising children for cleaning their plates) with children to prevent unhealthy child eating behaviors and childhood obesity. However, evidence suggests that providers frequently use CFP during mealtimes. Objective Using the Academy of Nutrition and Dietetics (2011) benchmarks for nutrition in child care as a framework, researchers assessed child-care providers’ perspectives regarding their use of mealtime CFP with young children (aged 2 to 5 years). Design Using a qualitative design, individual, face-to-face, semi-structured interviews were conducted with providers until saturation was reached. Participants/setting Providers were selected using maximum variation purposive sampling from varying child-care contexts (Head Start, Child and Adult Care Food Program [CACFP] e-funded centers, non-CACFP programs). All providers were employed full-time in Head Start or state-licensed center-based child-care programs, cared for children (aged 2 to 5 years), and were directly responsible for serving meals and snacks. Main outcome measure Child-care providers’ perspectives regarding CFP. Statistical analyses performed Thematic analysis using NVivo (version 9, 2010, QSR International Pty Ltd) to derive themes. Results Providers’ perspectives showed barriers, motivators, and facilitators regarding their use of mealtime CFP. Providers reported barriers to avoiding CFP such as CFP were effective for encouraging desired behaviors, misconceptions that providers were encouraging but not controlling children’s eating, and fear of parents’ negative reaction if their child did not eat. Providers who did not practice CFP were motivated to avoid CFP because they were unnecessary for encouraging children to eat, and they resulted in negative child outcomes and obesity. Facilitators as an alternative to CFP included practicing healthful feeding practices such as role modeling, peer modeling, and sensory exploration of foods. Conclusions Training providers about negative child outcomes associated with CFP, children’s ability to self-regulate energy intake, and differentiating between controlling and healthful feeding strategies may help providers to avoid CFP

    Human Brain Microvascular Endothelial Cells and Umbilical Vein Endothelial Cells Differentially Facilitate Leukocyte Recruitment and Utilize Chemokines for T Cell Migration

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    Endothelial cells that functionally express blood brain barrier (BBB) properties are useful surrogates for studying leukocyte-endothelial cell interactions at the BBB. In this study, we compared two different endothelial cellular models: transfected human brain microvascular endothelial cells (THBMECs) and human umbilical vein endothelial cells (HUVECs). With each grow under optimal conditions, confluent THBMEC cultures showed continuous occludin and ZO-1 immunoreactivity, while HUVEC cultures exhibited punctate ZO-1 expression at sites of cell-cell contact only. Confluent THBMEC cultures on 24-well collagen-coated transwell inserts had significantly higher transendothelial electrical resistance (TEER) and lower solute permeability than HUVECs. Confluent THBMECs were more restrictive for mononuclear cell migration than HUVECs. Only THBMECs utilized abluminal CCL5 to facilitate T-lymphocyte migration in vitro although both THBMECs and HUVECs employed CCL3 to facilitate T cell migration. These data establish baseline conditions for using THBMECs to develop in vitro BBB models for studying leukocyte-endothelial interactions during neuroinflammation
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