Moment-based Estimation of Mixtures of Regression Models

Finite mixtures of regression models provide a flexible modeling framework for many phenomena. Using moment-based estimation of the regression parameters, we develop unbiased estimators with a minimum of assumptions on the mixture components. In particular, only the average regression model for one of the components in the mixture model is needed and no requirements on the distributions. The consistency and asymptotic distribution of the estimators is derived and the proposed method is validated through a series of simulation studies and is shown to be highly accurate. We illustrate the use of the moment-based mixture of regression models with an application to wine quality data.Comment: 17 pages, 3 figure

Mississippi Registered Nurse Perceptions when Communicating with Limited-English-Speaking and Non-English-Speaking Patients

Communication serves as the foundation for safe and effective healthcare practice. Effective nurse-patient communication is the cornerstone of the nurse-patient relationship and is vital for the delivery of safe and effective healthcare. Research has shown patients who are communication impaired are at a greater risk of medical error and poorer health outcomes. A review of the literature revealed various nurse perceptions of barriers when providing care for limited-English-speaking patients and non-English-speaking patients. LEP and NEP patients also identified similar perceived barriers when receiving care. Both nurses and patients revealed a distrust for interpreters and interpreter services. The literature review revealed the need for further study into the perspective of registered nurses when caring for LEP and NEP patients. Communication is an important part of the nurse-patient relationship and is vital for the delivery of safe and effective health care. Increasing diversity among patient populations means healthcare professionals will find themselves caring for LEP or NEP more frequently and highlights the need to identify strategies for positively impacting healthcare encounters for LEP or NEP and healthcare providers. The purpose of this study was to explore the lived experience of Mississippi registered nurses communicating with LEP and NEP. A phenomenological approach was used to conduct the study. Participants were recruited until data saturation occurred, resulting in a total of six participants. Participants described experiencing anxiety when communicating with LEP and NEP due to feelings of helplessness and fear, limited cultural competence education/training, limited availability of interpreter services. Participants also described feelings of detachment from LEP and NEP due to the role language plays in forming a connection, especially in Mississippi. The study also found that participants feel that healthcare facilities have not prioritized improving communication with LEP or NEP which furthers the feelings of anxiety and detachment. The results of the study could serve as the foundation for further research into improving communication between nurses and LEP/NEP in the State of Mississippi

Semiparametric multi-parameter regression survival modelling

We consider a log-linear model for survival data, where both the location and scale parameters depend on covariates and the baseline hazard function is completely unspecified. This model provides the flexibility needed to capture many interesting features of survival data at a relatively low cost in model complexity. Estimation procedures are developed and asymptotic properties of the resulting estimators are derived using empirical process theory. Finally, a resampling procedure is developed to estimate the limiting variances of the estimators. The finite sample properties of the estimators are investigated by way of a simulation study, and a practical application to lung cancer data is illustrated

Análise da produção de leite como opção de renda na agricultura familiar na localidade de Esquina Salete Independência RS

A agricultura familiar é a base da produção de alimentos no Brasil. Neste sentido, o presente trabalho teve como objetivo entender se a produção de leite na localidade de Esquina Salete, município de Independência RS, é uma opção possível para gerar renda para subsistência das famílias pertencentes a agricultura familiar. Para atingir o objetivo foram realizadas pesquisas bibliográficas e trabalho de campo, com entrevistas e questionários. Os resultados mostraram que os produtores pesquisados, tem a produção de leite como principal atividade, e os índices de produção de leite de Esquina Salete estão acima da média geral do município. Todos os produtores recebem incentivos do poder público. A produção de leite, pela agricultura familiar em Esquina Salete, é uma atividade instável em relação ao preço recebido pelo litro de leite e passa por um período de redução dos valores. Mesmo enfrentando dificuldades, nos últimos anos, houve o acréscimo de um produtor na localidade e nenhuma desistência. Isto revela que Esquina Salete é um território de resistência da agricultura familiar produtora de leite e mesmo com dificuldades a produção de leite pela agricultura familiar ainda é uma opção de renda para as famílias.The familiar agriculture is the base of food production in Brazil. In this scenario, the given assignament has had a goal to understand if the dairy production made in Esquina Salete, Independência RS, is a possible option to generate income to the subsistence of the families belonging to family farming. To reach this goal there were made bibliographic research and fieldwork, with interviews and a quiz. The results showed that the interviewed producers have the dairy production as the main activity and the production's indexes from Esquina Salete are above the general media of the city. All the producers receive government incentive. The dairy production, by familiar producers in Esquina Salete is an instable activity related to the given price by the milk's when the liter goes through a low season. Even if they face difficulties, lately, there were an addition of a producer in the locality and no quitting. It reveals that Esquina Salete is a territory of resistance of family dairy farming and even with these difficulties dairy production by the familiar agriculture is still a way of income to the families

25-Hydroxyvitamin D and Peripheral Immune Mediators:Results from Two Nationwide Danish Pediatric Cohorts

(1) Background: We aimed to examine if 25-hydroxyvitamin D (25(OH)D) was related to the peripheral immunological and inflammatory signature both at birth, and in newly diagnosed patients with childhood type 1 diabetes (T1D) and their healthy controls; (2) Methods: The birth cohort consisted of 470 patients and 500 healthy controls. Dried blood samples were collected from the neonates in the period 1981–1999. The newly diagnosed cohort consisted of 460 patients and 453 siblings. Serum samples were collected in the period 1997–2005. A variety of peripheral immune mediators were measured and compared to total 25(OH)D levels (25(OH)D2 + 25(OH)D3). For each immune mediator, the relative change (RC) in the mean level was modeled by robust log-normal regression and correction for multiple testing was performed; (3) Results: Two associations were identified; there was a negative association between 25(OH)D (10 nmol/L increase) and leptin (RC (95% confidence interval (CI)), 0.98 (0.96; 1.00)), and a positive association between 25(OH)D (10 nmol/L increase) and the chemokine, chemokine (c-x-c motif) ligand (CXCL) 8 (RC (95% CI), 1.07 (1.01; 1.13)); (4) Conclusion: CXCL8 and leptin have significant associations with levels of 25(OH)D in the newly diagnosed cohort. These results do not indicate a strong influence of 25(OH)D on the peripheral immunological or inflammatory signature

Ultra fast miniaturized real-time PCR: 40 cycles in less than six minutes

We have designed, fabricated and tested a real-time PCR chip capable of conducting one thermal cycle in 8.5 s. This corresponds to 40 cycles of PCR in 5 min and 40 s. The PCR system was made of silicon micromachined into the shape of a cantilever terminated with a disc. The thin film heater and a temperature sensor were placed on the disc perimeter. Due to the system's thermal constant of 0.27 s, we have achieved a heating rate of 175°C s−1 and a cooling rate of −125°C s−1. A PCR sample encapsulated with mineral oil was dispensed onto a glass cover slip placed on the silicon disc. The PCR cycle time was then determined by heat transfer through the glass, which took only 0.5 s. A real-time PCR sample with a volume of 100 nl was tested using a FAM probe. As the single PCR device occupied an area of only a few square millimeters, devices could be combined into a parallel system to increase throughput

Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization:a study of healthy male volunteers

INTRODUCTION: The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia, however, remains unsettled, and the dissimilarities in physiologic properties suggest that they may represent 2 distinctively different pain entities. The aim of this study was to investigate the association between HPDT and BTS-induced secondary hyperalgesia. METHODS: A sample of 121 healthy male participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression scale (HADS) were also applied. RESULTS: A significant association between HPDT and the size of the area of secondary hyperalgesia (p<0.0001) was found. The expected change in area of secondary hyperalgesia due to a 1-degree increase in HPDT was estimated to be −27.38 cm(2), 95% confidence interval (CI) of −37.77 to −16.98 cm(2), with an R(2) of 0.19. Likewise, a significant association between HADS-depression subscore and area of secondary hyperalgesia (p=0.046) was found, with an estimated expected change in secondary hyperalgesia to a 1-point increase in HADS-depression subscore of 11 cm(2), 95% CI (0.19–21.82), and with R(2) of 0.03. We found no significant associations between secondary hyperalgesia area and PCS score or pain during thermal stimulation. CONCLUSION: HPDT and the area of secondary hyperalgesia after BTS are significantly associated; however, with an R(2) of only 19%, HPDT only offers a modest explanation of the inter-participant variation in the size of the secondary hyperalgesia area elicited by BTS

No Contribution of GAD-65 and IA-2 Autoantibodies around Time of Diagnosis to the Increasing Incidence of Juvenile Type 1 Diabetes:A 9-Year Nationwide Danish Study

Aims. A new perspective on autoantibodies as pivotal players in the pathogenesis of type 1 diabetes (T1D) has recently emerged. Our key objective was to examine whether increased levels of autoantibodies against the β-cell autoantigens glutamic acid decarboxylase (isoform 65) (GADA) and insulinoma associated antigen-2A (IA-2A) mirrored the 3.4% annual increase in incidence of T1D. Methods. From the Danish Childhood Diabetes Register, we randomly selected 500 patients and 500 siblings for GADA and IA-2A analysis (1997 through 2005). Blood samples were taken within three months after onset. A robust log-normal regression model was used. Nine hundred children and adolescents had complete records and were included in the analysis. Cochran-Armitage test for trend was used to evaluate changes in prevalence of autoantibody positivity by period. Results. No significant changes in levels of GADA and IA-2A were found over our 9-year study period. No trends in autoantibody positivity—in either patients or siblings—were found. Levels of GADA and IA-2A were significantly associated with HLA risk groups and GADA with age. Conclusion. The prevalence of positivity and the levels of GADA and IA-2A have not changed between 1997 and 2005 in newly diagnosed patients with T1D and their siblings without T1D