Modeling left-truncated and right-censored survival data with longitudinal covariates

There is a surge in medical follow-up studies that include longitudinal covariates in the modeling of survival data. So far, the focus has been largely on right-censored survival data. We consider survival data that are subject to both left truncation and right censoring. Left truncation is well known to produce biased sample. The sampling bias issue has been resolved in the literature for the case which involves baseline or time-varying covariates that are observable. The problem remains open, however, for the important case where longitudinal covariates are present in survival models. A joint likelihood approach has been shown in the literature to provide an effective way to overcome those difficulties for right-censored data, but this approach faces substantial additional challenges in the presence of left truncation. Here we thus propose an alternative likelihood to overcome these difficulties and show that the regression coefficient in the survival component can be estimated unbiasedly and efficiently. Issues about the bias for the longitudinal component are discussed. The new approach is illustrated numerically through simulations and data from a multi-center AIDS cohort study.Comment: Published in at http://dx.doi.org/10.1214/12-AOS996 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Health literacy and depression in women with type 2 diabetes mellitus

OBJECTIVES: The prevalence of diabetes mellitus has recently increased in Taiwan, and depression is common among these patients. Moreover, a lack of health literacy may lead to depression. In this study, we explored the correlation between health literacy and depression in diabetic women. METHODS: In this cross-sectional study, 152 women with type 2 diabetes mellitus were recruited from the outpatient clinic of a regional teaching hospital in Taiwan. The data were collected through medical records and a self-reported structured questionnaire, which included items on basic attributes, self-rated health status, the Center for Epidemiologic Studies Depression Scale (CES-D), and Chinese Health Literacy Scale for Diabetes (CHLSD). The results were analyzed using descriptive statistical analyses, bivariate correlation tests, and linear regression analyses. RESULTS: One hundred thirty-five valid questionnaires were obtained. Approximately 20% of the participants had a higher tendency toward depression as per their CES-D score, and the CHLSD results showed that 13.33% had poor health literacy. There was a negative correlation between health literacy and depressive tendencies after adjusting for self-rated health status, economic satisfaction status, employment status, and education level using multivariate linear regression analyses. For each 1-point rise in the CHLSD score, the CES-D score decreased by 0.17 points (z=2.05, p=0.042). CONCLUSIONS: A negative correlation was identified between health literacy and depression. Self-rated health status, economic satisfaction, employment status, and higher education level are factors that also affect depressive tendency among diabetic women

Symmetry breaking and criticality in tensor-product states

We discuss variationally optimized matrix-product states for the transverse-field Ising chain, using D*D matrices with small D=2-10. For finite system size N there are energy minimums for symmetric as well as symmetry-broken states, which cross each other at a field value hc(N,D); thus the transition is first-order. A continuous transition develops as N->infinity. The asymptotic critical behavior is then always of mean-field type (the magnetization exponent beta=1/2), but a window of field strengths where true Ising scaling holds (beta=1/8) emerges with increasing D. We also demonstrate asymptotic mean-field behavior for infinite-size two-dimensional tensor-product (iPEPS) states with small tensors.Comment: 4 pages, 5 figure

Cultivating Social Capital through Interactivity on Social Network Sites

The Internet has changed from an information tool to a social tool. More and more people use social networking sites such as Facebook to build and maintain numerous interpersonal relationships. The benefits of online social interaction can be manifested in bridging and bonding social capital. This study examined how the four dimensions of perceived interactivity (control, synchronicity, surveillance, and social bandwidth) affected users’ bridging and bonding social capital. Moreover, this study also assessed how the effects of perceived interactivity on bridging and bonding social capital were mediated by communication quality and social relationship support. This study recruited 422 respondents to participate in the survey. The first results showed that three out of four dimensions of perceived interactivity (control, synchronicity, and social bandwidth) positively influenced bridging and bonding social capital, whereas perceived surveillance negatively affected bridging social capital. Moreover, they have a stronger effect on bridging than on bonding social capital. The second findings revealed that the relationships between the two dimensions of perceived interactivity (synchronicity and social bandwidth) and bridging social capital were mediated by social relationship support

New Approach of the Water Resource Conservation in Taiwan — an Ecological Check for Reservoir Watershed Project (ECRWP)

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Diet Shapes Mortality Response to Trauma in Old Tephritid Fruit Flies.

Despite the importance of trauma in healthspan and lifespan in humans as well as in non-human species, with one important exception the literature in both gerontology and ecology contains virtually no experimental demographic studies concerned with trauma in any species. We used dietary manipulation [full diet (F) versus sugar-only (S)] to produce four levels of frailty in 55-day old tephritid fruit flies (Anastrepha ludens) that were then subject to the trauma of cage transfer stress (n = 900/sex in each of the 4 treatments). The key results included the following: (1) there is a trauma effect caused by the transfer that depends on previous diet before transfer, new diet after transfer and gender of the fly; (2) males are more vulnerable than females; (3) if initial diet was F, flies are relatively immune against the trauma, and the subsequent diet (F or S) does not matter; (4) however if initial diet was S, then the effect of the trauma depends largely on the diet after the transfer; (5) flies transferred from S to F diets do very well in terms of remaining longevity (i.e. greatest remaining longevity), while flies transferred from S to S diet do poorly (i.e. shortest remaining longevity). We discuss both the strengths and weaknesses of this study and implications of the results

Ultraviolet Lasing Characteristics of ZnS Microbelt Lasers

published_or_final_versio

Mothers and mother tongue : their role in promoting Foochow to their children

Research in settings where the Foochow population is small relative to other ethnic groups has indicated a shift away from Foochow towards Mandarin and English and the question raised is whether the same phenomenon is happening in Foochow-dominant settings. The study examined whether Foochow mothers promote use of the mother tongue by their children in Foochow-dominant towns in Sarawak. Interview data were collected from 30 participants from seven families, of which 14 were mothers. The results showed that the children's language use was in the hands ofthe mother more than the father although some Foochow mothers allowed the family situation to dictate the children's first language. Others took on a more active role in deciding the language(s) their children should learn, some going with and others going against the tide of social change. The demographic profiles ofthe families were examined to find out the factors influencing Foochow mothers to promote or demote their ethnic language in the family