1,720,999 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Incidence of and factors associated with discordant pathologic diagnosis in patients with suspected Burkitt Lymphoma treated in a low-resource setting
Get PDFThesis (Master's)--University of Washington, 2015Aim: To determine the frequency of discordant diagnosis of endemic Burkitt Lymphoma at the Uganda Cancer institute and to evaluate different baseline patient characteristics for their association with discordance and its impact on one year overall survival Background: Burkitt Lymphoma is the most common childhood malignancy in many countries of Sub-Saharan Africa. Overall survival rates for this disease in low-resource settings are far below those seen for a similar disease in more affluent countries. Resources for pathology are scarce in many countries where Burkitt Lymphoma is endemic, leading to high rates of inaccurate diagnoses, thereby possibly contributing to the lower overall survival rates. A clinical care project at the Uganda Cancer Institute (UCI) in Kampala, Uganda has been following patients with Burkitt Lymphoma for more than 2 years, with preliminary data showing a high rate of diagnostic discordance. Method: All patients presenting for care at the UCI between July 2012 and July 2014 with suspected BL and two independent histopathologic evaluations of the same tumor biopsy were eligible for this study. Baseline demographic and clinical characteristics were described for the entire cohort and by discordance status. Kappa statistics were calculated to determine the rate of agreement between two pathology labs involved in the project. Poisson regression analysis was used to determine associations of baseline factors with discordance. To determine one year overall survival the Kaplan-Meier Method was used. Findings: 57 patients were eligible for the study. The percentage of discordance for BL vs. “other” was 32%. Older age and central nervous system involvement were associated with a higher frequency of discordant diagnosis. There was a trend towards elevated LDH being associated with discordance, though this was not statistically significant. These associations were attenuated when adjusting for age. Overall survival was 55% for the entire cohort, and 70% and 39% for patients without and with discordance respectively. The difference in survival between the groups did not meet statistical significance. Conclusions: Discordance was a frequent event in our study setting. Baseline factors associated with discordance may be used to guide decisions regarding more extensive diagnostic workup, but need to be confirmed in larger studies. Cheaper and sustainable pathology testing needs to be made available for countries with limited resources
The impact of HIV infection on cervical cancer presentation and survival in Uganda
Get PDFThesis (Master's)--University of Washington, 2017-06Objectives: To determine how HIV infection impacts cervical cancer stage and overall survival (OS) among Ugandan women. Methods/Materials: Women diagnosed with cervical cancer were followed between 2013 and 2015 at the Uganda Cancer Institute (UCI). A Poisson regression model was fit to calculate prevalence ratios (PR) for the association between HIV infection and late stage at cancer diagnosis. The association between HIV infection and OS after cervical cancer diagnosis was evaluated using a Cox proportional hazards model. Results: 53 HIV-positive and 96 HIV-negative participants were enrolled. Median age at diagnosis was 44 years (IQR 39-48) for HIV-positive and 54 years (IQR 47-62) for HIV-negative participants. 77% of HIV-positive participants were receiving antiretroviral therapy. Median baseline CD4 count was 373 cells/mm3 (IQR 300-502) for HIV-positive participants versus 926 cells/mm3 (IQR 639-1045) for HIV-negative participants. Thirty-two percent of HIV-positive participants were diagnosed with late stage cervical cancer (III-IV) versus 39% of HIV-negative participants (p=0.4). After adjusting for age, number of live births, and cost of transportation, no association was found between late stage at cancer diagnosis and HIV status (PR 1.03, 95%CI 0.60-1.78, p=0.9). Most women presenting for care received treatment (85% of HIV-positive versus 75% of HIV-negative), though almost half who received radiotherapy did not receive adequate treatment. There were 35 deaths among HIV-positive and 45 among HIV-negative participants. The median OS was significantly shorter for HIV-positive participants (14.7 months vs 24.3 months for HIV-negative participants, p=0.05). After adjusting for age and stage, HIV infection was weakly, but not statistically significantly, associated with OS (HR 1.35, 95%CI 0.83-2.17). Conclusions: Cervical cancer remains morbid and often incompletely treated in Uganda. HIV infection was not associated with the stage of cervical cancer at diagnosis, but may be weakly associated with shorter survival, although our limited sample size prohibits definitive statistical evidence
Readily-Available Antibiotic Formulations to Improve Outcomes in Cancer Patients with Severe Sepsis and Septic Shock
Get PDFThesis (Master's)--University of Washington, 2015Background: Cancer patients are at high risk for severe sepsis (SS) and septic shock (SSh) and delay to effective antimicrobial therapy (ABx) is strongly associated with increased mortality. Anti-pseudomonal beta-lactam intravenous monotherapy is equally effective and less toxic than combination therapy for uncomplicated neutropenic fever, but combination therapy may be superior for more severe disease. Methods: We implemented a clinical algorithm to simplify timely and effective empiric ABx and other resuscitative care to cancer outpatients with SS/SSh prior to hospital admission. Triple therapy with meropenem, tobramycin and linezolid or alternatives such as aztreonam for penicillin-allergic patients can be co-administered and provides broad coverage for resistant organisms typically encountered in this population. A pre-printed order form triggered dispensing of kits containing ABx, fluids and dexamethasone. We performed a retrospective cohort study to assess the impact of this strategy. Results: From 1/1/08 through 1/31/12, 162 patients met inclusion criteria. Median age was 53 (IQR: 42 – 63) years and 65% were male. The majority of patients (87%) had hematopoietic malignancies. 77 (48%) were hematopoietic stem cell transplant recipients and 80 (49%) were neutropenic. SSh was diagnosed in 25 patients (15%), SS in 46 (28%), sepsis in 72 (44%) alternative diagnosis in 6 (4%) and infection without systemic inflammatory response syndrome in 13 (8%). Median time from clinical encounter to ABx administration was 111 (IQR: 60 – 178) minutes, 93% had blood cultures drawn prior to ABx, 46% received dexamethasone and 99% had crystalloid infusion started before hospital transfer. De-escalation on hospital day 1 occurred in 95% of persons admitted. 44% of 25 persons with SSh received vasopressors. 71 persons (44%) had bacteremia and 18% of 93 isolates were multidrug resistant. Possible nephrotoxicity occurred in 7 patients. 30 day mortality was 6/160 (4%) including 3/71 (4%) with SS/SSh. For each hour delay to administer antibiotics, there was an18% increased risk of developing SSh or death within 30 days (95% CI: 4 – 34%), p=0.01. Conclusions: A program to simplify choice of aggressive empiric ABx among cancer patients presenting to an ambulatory clinic with suspected sepsis was associated with excellent survival in those with SS/SSh, without excessive adverse events or inappropriately long empiric ABx durations
Predictors of late presentation of cervical cancer in HIV-positive Ugandan women
No full textThesis (Master's)--University of Washington, 2012Predictors of late stage presentation of cervical cancer in HIV-positive Ugandan women Background Cervical cancer is one of the leading causes of cancer deaths in women globally and it is the number one cause of cancer morbidity and mortality in Ugandan women. No data on predictors of late stage cervical cancer in HIV-positive women presenting for oncologic care in Uganda is available. It is also not known how HIV care providers in Uganda view integration of cervical cancer screening in routine HIV care. Methods This was a cross sectional study of HIV-positive women with cervical cancer. Data were collected on demographics, HIV history, including CD4+ T-cell count, and cervical cancer history and stage. In addition, focus group discussions were held with staff in HIV clinics. Results Forty women completed study procedures, with a median age of 40 years (range 25 - 68). Thirty-two (40%) had late stage cervical cancer (FIGO stage III and IV). In bivariate analysis, there was an association between young age at sexual debut (16 years and younger) and presentation with late stage cervical cancer (OR = 0.273, p = 0.043). Having 2 or more lifetime sexual partners was also associated with 80% increased odds (OR=1.800, p=0.045). Importantly, CD4+ T-cell count were not associated with late stage cervical cancer. Qualitative data showed that HIV care staffs know that HIV-positive women are at high risk of cervical cancer, there is lack of awareness among the HIV- positive women and some of the key reasons why cervical cancer screening is not done routinely in HIV care are absence of a policy and HIV care guidelines that integrate the intervention. Conclusions Many HIV-positive women present with late stage cervical cancer. Women with low SES (poor, low education) with early sexual debut and multiple sexual partners were more likely to presen
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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