The cutoff phenomenon describes a case where a Markov chain exhibits a sharp transition in its convergence to stationarity. In 1996, Diaconis surveyed this phenomenon, and asked how one could recognize its occurrence in families of finite ergodic Markov chains. In 2004, the third author noted that a necessary condition for cutoff in a family of reversible chains is that the product of the mixin...

The B-cell repertoire in neonatal mice contains predominant clonotypes that are reproducibly expressed at particular times after birth. We have isolated and sequenced heavy and light chain cDNA clones from three 2,4-dinitrophenyl-specific neonatal hybridomas. Two of these hybridomas (TF2-36 and TF5-139) express idiotypes (Ids) that predominate during the first days after birth, and the third hy...

BACKGROUND Skilled birth attendance is one of the key factors in improving maternal health but less than 50% of women in sub-Saharan African countries do not have the opportunity to be attended to by skilled personnel during childbirth. The aim of the study was to assess the factors determining women's preference for a place to give birth in Dodoma Region, Tanzania. METHODS This study employe...

Aim: To determine the visual functions, at age 10–12 years, of a geographically based cohort of children of birth weight less than 1701 g. The results were compared to a group of children born at full term. Methods: 572 low birthweight (LBW) ‘‘low birthweight cohort’’ children who had been examined in the neonatal period were invited for review at 10–12 years of age. 169 11 year old schoolchild...

BACKGROUND The Conditional Autoregressive (CAR) model is widely used in many small-area ecological studies to analyse outcomes measured at an areal level. There has been little evaluation of the influence of different neighbourhood weight matrix structures on the amount of smoothing performed by the CAR model. We examined this issue in detail. METHODS We created several neighbourhood weight m...

OBJECTIVE To assess associations between unconventional natural gas development (UGD) and perinatal outcomes. METHODS We conducted a retrospective birth cohort study among 158,894 women with a birth or fetal death from November 30, 2010-November 29, 2012 in the Barnett Shale, in North Texas. We constructed three UGD-activity metrics by calculating the inverse distance-weighted sum of active w...

OBJECTIVE To investigate delays in first and third dose diphtheria-tetanus-pertussis (DTP1 and DTP3) vaccination in low-birth-weight infants in Ghana, and the associated determinants. METHODS We used data from a large, population-based vitamin A trial in 2010-2013, with 22 955 enrolled infants. We measured vaccination rate and maternal and infant characteristics and compared three categories ...

BACKGROUND Evidence suggests that air pollution exposure adversely affects pregnancy outcomes. Few studies have examined individual-level intraurban exposure contrasts. OBJECTIVES We evaluated the impacts of air pollution on small for gestational age (SGA) birth weight, low full-term birth weight (LBW), and preterm birth using spatiotemporal exposure metrics. METHODS With linked administrat...

OBJECTIVE To investigate the risk of early childhood cancers associated with the mother's exposure to radiofrequency from and proximity to macrocell mobile phone base stations (masts) during pregnancy. DESIGN Case-control study. SETTING Cancer registry and national birth register data in Great Britain. PARTICIPANTS 1397 cases of cancer in children aged 0-4 from national cancer registry 19...

BACKGROUND Area-level socioeconomic disparities have long been associated with adverse pregnancy outcomes. Crime is an important element of the neighborhood environment inadequately investigated in the reproductive and public health literature. When crime has been used in research, it has been variably defined, resulting in non-comparable associations across studies. METHODS Using geocoded li...