343 research outputs found

    Developing Mediators: An Analysis of the Changing Associations of Ghanaian Internet Cafe Users between 2003 and 2014

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    This study examines interview data gathered a decade apart, in 2003 and in 2014.The analysis answers the questions: How were cafĂ© patrons using the Internet in 2003 and how do the 2003 findings of this study compare to the findings of other studies conducted around the same time? How has Internet usage changed between 2003 and 2014? How has the Internet cafĂ© business changed over the last decade? This study starts by reviewing the theory and literature which informs studies of the Internet and Internet cafĂ©s in developing countries. Two years were spent discovering the fate of the 2003 locations. The data that were used for analysis were gathered at these locations, or their walking distance equivalents, using ethnographic interviews. An argument is made that the Internet can either be a Black-box or a Quasi-actant in an Actor-network account, depending on how the subject frames its influence. The study then compares the findings from 2003 to the findings presented in Invisible Users, another study of Ghana\u27s Internet cafĂ©s conducted in 2005(Burrell 2011).This study makes the argument that “Invisible Users” were only one of many different types of cafĂ© users. It is also argued that pornography played a multi-faceted role in the narratives of cafĂ© patrons. Differences and similarities in both patron usage and the cafĂ© business itself, between 2003 and 2014 are discussed Finally, this study concludes by presenting an actor-network description of the flow of action for both the cafĂ© business and cafĂ© patrons by using the first three uncertainties identified in Reassembling the Social (Latour 2007)

    Digital Photograph Analysis for Measuring Percent Plant Cover in the Arctic

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    Long-term satellite remote sensing data, when properly calibrated and validated against ground monitoring, could provide valuable data sets for assessing climate change impacts on ecosystems, wildlife, and other important aspects of life in the Arctic. Percent plant cover is ideal for seasonal and long-term ground monitoring because it can be observed non-destructively and is closely related to other key ecosystem variables, such as biomass and leaf area index (LAI). Accurately measuring percent plant cover in the Arctic, however, has been a challenge. Advances in digital photography and imageprocessing techniques have provided the potential to measure vegetation cover accurately. In this paper we report an adapted method for quantifying percent plant cover based on plot digital photograph classification (PDPC). In this digital image analysis, the red, green, and blue image channels and the intensity, hue, and saturation image channels were used together to ensure more accurate cover measurement and labeling of plant species. We evaluated the accuracy of the PDPC method and two other techniques, visual estimate and digital grid overlay, by testing against artificial plots with known percent cover, by comparing with destructively measured LAI, and by comparing results of the three methods. Our evaluation indicates that the PDPC method is the most accurate. In addition, PDPC has the advantages of being objective, quick in the field, and suitable for measuring percent plant cover in the Arctic at the level of functional types or species groups.Lorsqu'elles sont bien calibrĂ©es et qu'elles sont validĂ©es contre le dĂ©pistage terrestre, les donnĂ©es rĂ©sultant de la tĂ©lĂ©dĂ©tection satellitaire Ă  long terme pourraient fournir d'importants ensembles de donnĂ©es en vue de l'Ă©valuation des incidences du changement climatique sur les Ă©cosystĂšmes, la faune et d'autres aspects-clĂ©s de la vie dans l'Arctique. Le pourcentage de couverture vĂ©gĂ©tale est idĂ©al pour le dĂ©pistage saisonnier et le dĂ©pistage terrestre Ă  long terme parce qu'il peut ĂȘtre observĂ© sans qu'il n'y ait de destruction et parce qu'il est Ă©troitement liĂ© Ă  d'autres variables-clĂ©s se rapportant aux Ă©cosystĂšmes, comme la biomasse et l'indice de surface foliaire (ISF). Toutefois, dans l'Arctique, la mesure exacte du pourcentage de couverture vĂ©gĂ©tale reprĂ©sente un dĂ©fi. Les progrĂšs rĂ©alisĂ©s dans les domaines de la photographie numĂ©rique et des techniques de traitement d'images fournissent la possibilitĂ© de mesurer la couverture vĂ©gĂ©tale avec prĂ©cision. Dans cette communication, nous faisons Ă©tat d'une mĂ©thode adaptĂ©e permettant de quantifier le pourcentage de couverture vĂ©gĂ©tale en fonction de la classification de photographies numĂ©riques de parcelles. Dans le cadre de l'analyse d'images numĂ©riques, les canaux rouges, verts et bleus des images ainsi que les canaux d'intensitĂ©, de tonalitĂ© et de saturation des images ont Ă©tĂ© utilisĂ©s pour donner lieu Ă  la mesure plus exacte de la couverture vĂ©gĂ©tale et Ă  l'Ă©tiquetage des espĂšces vĂ©gĂ©tales. Nous avons Ă©valuĂ© l'exactitude de la mĂ©thode de classification de photographies numĂ©riques de parcelles de mĂȘme que celle de deux autres techniques, soit l'estimation visuelle et la superposition de grilles numĂ©riques en faisant des essais Ă  la lumiĂšre de parcelles artificielles dont le pourcentage de couverture vĂ©gĂ©tale Ă©tait connu et en les comparant avec des ISF mesurĂ©s de maniĂšre destructive, puis en comparant les rĂ©sultats des trois mĂ©thodes. Selon notre Ă©valuation, la mĂ©thode consistant en la classification de photographies numĂ©riques de parcelles PDPC est la plus prĂ©cise. La classification de photographies numĂ©riques de parcelles a Ă©galement l'avantage d'ĂȘtre objective, d'ĂȘtre rapide sur le terrain et de se prĂȘter Ă  la mesure du pourcentage de couverture vĂ©gĂ©tale dans l'Arctique en ce qui a trait aux types fonctionnels ou aux groupements d'espĂšces

    A complex speciation-richness relationship in a simple neutral model

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    Speciation is the "elephant in the room" of community ecology. As the ultimate source of biodiversity, its integration in ecology's theoretical corpus is necessary to understand community assembly. Yet, speciation is often completely ignored or stripped of its spatial dimension. Recent approaches based on network theory have allowed ecologists to effectively model complex landscapes. In this study, we use this framework to model allopatric and parapatric speciation in networks of communities and focus on the relationship between speciation, richness, and the spatial structure of communities. We find a strong opposition between speciation and local richness, with speciation being more common in isolated communities and local richness being higher in more connected communities. Unlike previous models, we also find a transition to a positive relationship between speciation and local richness when dispersal is low and the number of communities is small. Also, we use several measures of centrality to characterize the effect of network structure on diversity. The degree, the simplest measure of centrality, is found to be the best predictor of local richness and speciation, although it loses some of its predictive power as connectivity grows. Our framework shows how a simple neutral model can be combined with network theory to reveal complex relationships between speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference

    Bedside Endoscopic Ultrasound in Critically Ill patients

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    Background. The aim of this study was to evaluate the role and impact of EUS in the management of critically ill patients. Methods. We retrospectively identified all patients at our institution over a 68-month period in whom bedside inpatient EUS was performed. EUS was considered to have a significant impact if a new diagnosis was established and/or the findings altered subsequent clinical management. Results. Fifteen patients (9 male; mean age 58 ± 15 years) underwent bedside EUS without complications. EUS-FNA (median 4 passes; range 2–7) performed in 12 (80%) demonstrated a malignant mediastinal mass/lymph node (5), pancreatic abscess (1), excluded a pelvic abscess (1), established enlarged gastric folds as benign (1) and excluded malignancy in enlarged mediastinal (1) and porta hepatis adenopathy (1). In two patients, EUS-FNA failed to diagnose mediastinal histoplasmosis (1) and a hemorrhagic pancreatic pseudocyst (1). In three diagnostic exams without FNA, EUS correctly excluded choledocholithaisis (n = 1) and cholangiocarcinoma (1), and found gastric varices successfully thrombosed after previous cyanoacrylate injection (1). EUS was considered to have an impact in 13/15 (87%) patients. Conclusions. In this series, bedside EUS in critically ill patients was technically feasible, safe and had a major impact on the majority of patients

    Clinical Study Bedside Endoscopic Ultrasound in Critically Ill patients

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    Background. The aim of this study was to evaluate the role and impact of EUS in the management of critically ill patients. Methods. We retrospectively identified all patients at our institution over a 68-month period in whom bedside inpatient EUS was performed. EUS was considered to have a significant impact if a new diagnosis was established and/or the findings altered subsequent clinical management. Results. Fifteen patients (9 male; mean age 58 ± 15 years) underwent bedside EUS without complications. EUS-FNA (median 4 passes; range 2–7) performed in 12 (80%) demonstrated a malignant mediastinal mass/lymph node (5), pancreatic abscess (1), excluded a pelvic abscess (1), established enlarged gastric folds as benign (1) and excluded malignancy in enlarged mediastinal (1) and porta hepatis adenopathy (1). In two patients, EUS-FNA failed to diagnose mediastinal histoplasmosis (1) and a hemorrhagic pancreatic pseudocyst (1). In three diagnostic exams without FNA, EUS correctly excluded choledocholithaisis (n = 1) and cholangiocarcinoma (1), and found gastric varices successfully thrombosed after previous cyanoacrylate injection (1). EUS was considered to have an impact in 13/15 (87%) patients. Conclusions. In this series, bedside EUS in critically ill patients was technically feasible, safe and had a major impact on the majority of patients. 1

    Utility of EUS following endoscopic polypectomy of high-risk rectosigmoid lesions

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    BACKGROUND: The utility of endoscopic ultrasound (EUS) compared with standard white light endoscopy (WLE) following recent polypectomy of high-risk colorectal polyps is unknown. OBJECTIVE: To assess the incremental yield of EUS after endoscopic polypectomy of a high-risk rectal lesion. DESIGN: Retrospective cohort. SETTING: Tertiary referral center. MATERIALS AND METHODS: Patients referred for EUS following attempted endoscopic resection of a high-risk rectal neoplasm, defined as a tubulovillous adenoma, tubular adenoma with high-grade dysplasia, carcinoid, carcinoma in-situ or adenocarcinoma (CA). INTERVENTIONS: Sigmoidoscopy ± mucosal biopsy and EUS ± fine-needle aspiration (FNA) to evaluate for: (1) Residual polyp/tumor in the rectal wall or (2) peritumoral adenopathy. MAIN OUTCOME: Sensitivity and specificity for detection of residual neoplasia for WLE ± biopsy (WLE/BX) and EUS ± FNA for cancer (CA group) or benign disease (non-CA group). The incremental yield of EUS defined as: (1) Residual intramural neoplasia not present on WLE ± BX and; (2) abnormal peritumoral adenopathy. RESULTS: A total of 70 patients (mean age 64 ± 11 years, 61% male) with a final diagnosis of CA (n = 38) and non-CA (n = 32) were identified. There was no difference between the sensitivity and specificity of WLE alone (65% and 84%), WLE with biopsy (71% and 95%), and EUS (59% and 84%), for the detection of residual neoplasia (P > 0.05 for all). EUS identified 3 masses missed by WLE, all in the CA group. A malignant (n = 2) or benign (n = 3) node was identified in 5 (13%) CA patients; EUS-FNA in two showed residual malignancy in one and a reactive lymph node (LN) in one. No LNs were identified in the non-CA patients. LIMITATIONS: Retrospective design, incomplete follow-up in some patients. CONCLUSION: Following endoscopic polypectomy of high-risk rectal neoplasia, the incremental yield of EUS compared with WLE/BX for evaluation of residual disease appears limited, especially in patients with benign disease

    Performance characteristics of EUS for locoregional evaluation of ampullary lesions

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    Background The accuracy of EUS in the locoregional assessment of ampullary lesions is unclear. Objectives To compare EUS with ERCP and surgical pathology for the evaluation of intraductal extension and local staging of ampullary lesions. Design Retrospective cohort study. Setting Tertiary-care referral center. Patients All patients who underwent EUS primarily for the evaluation of an ampullary lesion between 1998 and 2012. Intervention EUS. Main Outcome Measurements Comparison of EUS sensitivity/specificity for intraductal and local extension with ERCP and surgical pathology by using the area under the receiver-operating characteristic (AUROC) curves and outcomes of the subgroup referred for endoscopic papillectomy. Results We identified 119 patients who underwent EUS for an ampullary lesion, of whom 99 (83%) had an adenoma or adenocarcinoma. Compared with ERCP (n = 90), the sensitivity/specificity of EUS for any intraductal extension was 56%/97% (AUROC = 0.77; 95% confidence interval [CI], 0.64-0.89). However, when using surgical pathology as the reference (n = 102), the sensitivity/specificity of EUS (80%/93%; AUROC = 0.87; 95% CI, 0.76-0.97) and ERCP (83%/93%; AUROC = 0.88; 95% CI, 0.77-0.99) were comparable. The overall accuracy of EUS for local staging was 90%. Of 58 patients referred for endoscopic papillectomy, complete resection was achieved in 53 (91%); in those having intraductal extension by EUS or ERCP, complete resection was achieved in 4 of 5 (80%) and 4 of 7 (57%), respectively. Limitation Retrospective design. Conclusions EUS and ERCP perform similarly in evaluating intraductal extension of ampullary adenomas. Additionally, EUS is accurate in T-staging ampullary adenocarcinomas. Future prospective studies should evaluate whether EUS can identify characteristics of ampullary lesions that appropriately direct patients to endoscopic or surgical resection. (Gastrointest Endosc 2015;81:380-8.

    Global Genetic Diversity of Human Metapneumovirus Fusion Gene

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    We analyzed 64 human metapneumovirus strains from eight countries. Phylogenetic analysis identified two groups (A and B, amino acid identity 93%–96%) and four subgroups. Although group A strains predominated, accounting for 69% of all strains, as many B as A strains were found in persons >3 years of age

    Loss of CIC promotes mitotic dysregulation and chromosome segregation defects

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    Background: CIC is a transcriptional repressor inactivated by loss-of-function mutations in several cancer types, including gliomas, lung cancers, and gastric adenocarcinomas. CIC alterations and/or loss of CIC activity have been associated with poorer outcomes and more aggressive phenotypes across cancer types, which is consistent with the notion that CIC functions as a tumour suppressor across a wide range of contexts. Results: Using mammalian cells lacking functional CIC, we found that CIC deficiency was associated with chromosome segregation (CS) defects, resulting in chromosomal instability and aneuploidy. These CS defects were associated with transcriptional dysregulation of spindle assembly checkpoint and cell cycle regulators. We also identified novel CIC interacting proteins, including core members of the SWI/SNF complex, and showed that they cooperatively regulated the expression of genes involved in cell cycle regulation. Finally, we showed that loss of CIC and ARID1A cooperatively increased CS defects and reduced cell viability. Conclusions: Our study ascribes a novel role to CIC as an important regulator of the cell cycle and demonstrates that loss of CIC can lead to chromosomal instability and aneuploidy in human and murine cells through defects in CS, providing insight into the underlying mechanisms of CIC's increasingly apparent role as a "pan-cancer" tumour suppressor
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