2,976,058 research outputs found

    The treatment of missing data on placement tools for predicting success in college algebra at the University of Alaska

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    Master's Project (M.S.) University of Alaska Fairbanks, 2014This project investigated the statistical significance of baccalaureate student placement tools such as tests scores and completion of a developmental course on predicting success in a college level algebra course at the University of Alaska (UA). Students included in the study had attempted Math 107 at UA for the first time between fiscal years 2007 and 2012. The student placement information had a high percentage of missing data. A simulation study was conducted to choose the best missing data method between complete case deletion, and multiple imputation for the student data. After the missing data methods were applied, a logistic regression with fitted with explanatory variables consisting of tests scores, developmental course grade, age (category) of scores and grade, and interactions. The relevant tests were SAT math, ACT math, AccuPlacer college level math, and the relevant developmental course was Devm /Math 105. The response variable was success in passing Math 107 with grade of C or above on the first attempt. The simulation study showed that under a high percentage of missing data and correlation, multiple imputation implemented by the R package Multivariate Imputation by Chained Equations (MICE) produced the least biased estimators and better confidence interval coverage compared to complete cases deletion when data are missing at random (MAR) and missing not at random (MNAR). Results from multiple imputation method on the student data showed that Devm /Math 105 grade was a significant predictor of passing Math 107. The age of Devm /Math 105, age of tests, and test scores were not significant predictors of student success in Math 107. Future studies may consider modeling with ALEKS scores, and high school math course information

    Possible protective effect of green tea intake on risk of adult leukaemia

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    In a case–control study of 107 adults with leukaemia and 110 orthopaedic controls in China, a reduced risk was found with longer duration, higher quantity, and frequency of green tea intake

    Teamwork Process Among Amanah Ikhtiar Malaysia (AIM) Participants. Case Study in Hulu Langat District

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    The present research sought to examine the teamwork performance among AIM microcredit participants based on Tuckman (1965) model. Hence, the author elaborates the level of teamwork process such as forming, norming, storming and performing in a group among AIM participant in Daerah Hulu Langat. The AIM is replication of the Grameen Bank approach in Malaysia and the teamwork concept was apply which is the scheme must be apply in a group and not in individual. Self- administrative questionnaire was applied to conduct a data collection and a sample of 160 respondents among participant from Sungai Gabai, Sungai Ramal, Sungai Chua, Sungai Tangkas, Bukit Mewah, Semenyih and Sungai Jelok in Kajang were chosen based on stratified and simple random sampling techniques to complete the survey. Researcher suggests the finding indicate that the high level stage in teamwork process is forming, storming and performing stage. Only norming stage was in moderate level. Consequently, high and positive teamwork resulted efficiencies in the microfinance group. Teamwork with the right process can achieved positive outcome among AIM microcredit participants

    Septic Abortion Managed in a Tertiary Hospital in West Bengal

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    Background: Septic abortion is still a challenging problem and a major cause of maternal mortality and morbidity in developing countries.Aim: The present study was conducted to estimate incidence, causes, risk factors, associated microorganisms, and treatment modalities of cases of septic abortion managed in a tertiary health care in West Bengal.Subjects and Methods: It was a cross‑sectional study carried out in Burdwan Medical College and Hospital in West Bengal between July 2011 and June 2012. On admission a thorough history was taken, examination was done, and investigations were carried. Depending on the examination findings the cases were grouped into three grades‑grade I: The infection localized in the uterus; grade II: The infection spread beyond the uterus to the parametrium, tubes, and ovaries or pelvic peritoneum; grade III: Generalized peritonitis and/or endotoxic shock or jaundice or acute renal failure. Statistical analysis was done by using Epi Info™ software (Version 3.5.1, CDC) after proper arrangement of all the data in tabular form and presented as simple percentage.Results: During the period, 1297 cases of abortion were admitted among which 107 were septic abortions, thus giving the incidence of the latter as 8.2% (107/1297). Forty‑three percent cases of septic abortion (46/107) were in grade I, 21.5% (23/107) in grade II, and 35.5% (38/107) in grade III. The modal age group of the patients was 15‑25 years (49.5%). Majority of the subjects were married (77.6%; 83/107) and multiparous (60.7%; 65/107). Similarly, most of them (71%; 76/107) were from low socioeconomic class. Ninety percent of the patients (96/107) had induced abortion. The common clinical features at presentation were pallor (88.8%; 95/107) and fever (86.0%; 92/107). Escherichia coli (62.6%; 67/107) and Klebsiella pneumonia (32.75%; 35/107) were the most common organism isolated. The case fatality from septic abortion in this study was 13.1% and the condition accounted for 15.4% of total maternal mortality within the period reviewed.Conclusion: The incidence of septic abortion in this study is relatively high, and majority of the cases resulted from attempted termination of pregnancy. It is a significant contributor to maternal mortality. Promotion of family planning and legalization of abortion services will go a long way in reducing the incidence of septic abortion and itsassociated complications. Keywords: Asia, management, maternal mortality, outcome, septic abortio

    Influence of correlated impurities on conductivity of graphene sheets: Time-dependent real-space Kubo approach

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    Exact numerical calculations of the conductivity of graphene sheets with random and correlated distributions of disorders have been performed using the time-dependent real-space Kubo formalism. The disorder was modeled by the long-range Gaussian potential describing screened charged impurities and by the short-range potential describing neutral adatoms both in the weak and strong scattering regime. Our central result is that correlation in the spatial distribution for the strong short-range scatterers and for the long-range Gaussian potential do not lead to any enhancement of the conductivity in comparison to the uncorrelated case. Our results strongly indicate that the temperature enhancement of the conductivity reported in the recent study (Yan and Fuhrer, Phys. Rev. Lett. 107, 206601 (2011)) and attributed to the effect of dopant correlations was most likely caused by other factors not related to the correlations in the scattering potential.Comment: 14 pages, 10 figure

    Children with pertussis inform the investigation of other pertussis cases among contacts

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    BACKGROUND: The number of reported pertussis has increased in the last two decades. However, many cases of pertussis may be underreported or not diagnosed. The World Health Organization estimates that pertussis causes 200,000-400,000 deaths each year, most deaths are in infants and in developing countries. Infants with pertussis can indicate an undetected source cases in the community. METHODS: At a University Hospital in Brazil individuals that had frequent contacts with a child with confirmed pertussis (the index case) and had recent history of cough were enrolled into the study. Nasopharyngeal swabs were collected from every contact that had cough within the last 21 days. Cases confirmation followed the guidelines of the Center for Disease Control and Prevention-Atlanta, USA. RESULTS: Pertussis diagnosis was confirmed in 51 children, (considered the index cases). Among the index cases, 72.5% (37/51) were under 6 months of age; culture for Bordetella pertussis was positive in 78.4% (40/51). Pertussis was confirmed in 39% (107/276) of the contacts of 51 index cases. Among these contacts identified as a pertussis case, 40.2% (43/107) were between 6 months and 111/2 years of age and 59.8% (64/107) were older than 111/2 years of age. Pertussis was confirmed by culture in 11.2% (12/107) of them and by epidemiologic linkage in 88.8% (95/107). Each index case allowed identifying two new cases of pertussis. CONCLUSION: Public health authorities should consider implementing early recognition of pertussis index cases and searching for pertussis cases among the contacts. Treatment of the cases and prophylaxis of the contacts is fundamental to control outbreaks in the community
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