Relation Between First Arrival Time and Permeability in Self-Affine Fractures with Areas in Contact

We demonstrate that the first arrival time in dispersive processes in self-affine fractures are governed by the same length scale characterizing the fractures as that which controls their permeability. In one-dimensional channel flow this length scale is the aperture of the bottle neck, i.e., the region having the smallest aperture. In two dimensions, the concept of a bottle neck is generalized to that of a minimal path normal to the flow. The length scale is then the average aperture along this path. There is a linear relationship between the first arrival time and this length scale, even when there is strong overlap between the fracture surfaces creating areas with zero permeability. We express the first arrival time directly in terms of the permeability.Comment: EPL (2012)

A Test of Kangaroo Care on Preterm Infant Breastfeeding

To test the effects of kangaroo care (KC) on breastfeeding outcomes in preterm infants compared to two control groups and to explore whether maternal-infant characteristics and the mother’s choice to use KC were related to breastfeeding measures

Patterns of Distress in African American Mothers of Preterm Infants

Objective: To examine inter-relationships among stress due to infant appearance and behavior in the NICU, parental role alteration stress in the NICU, depressive symptoms, state anxiety, posttraumatic stress symptoms, and daily hassles exhibited by African American mothers of preterm infants and to determine whether there were sub-groups of mothers based on patterns of psychological distress. Method: 177 African American mothers completed questionnaires on their psychological distress at enrollment during infant hospitalization and 2, 6, 12, 18, and 24 months after term. Results: Psychological distress measures were inter-correlated. There were four latent classes of mothers: the low distress class with low scores on all measures; the high NICU-related stress class with high infant appearance and parental role stress and moderate scores on other measures; the high depressive symptoms class with high depressive symptoms and state anxiety and moderately elevated scores on NICU-related stress and post-traumatic stress symptoms; the extreme distress class with the highest means on all measures. Infants in the high stress class were sicker than infants in the other classes. The extreme distress class mothers averaged the lowest educational level. The classes differed on distress measures, worry about the child, and parenting stress through 24 months with the extreme distress class having the highest values. Conclusion: Although different types of maternal psychological distress were substantially related, there were distinct sub-groups of mothers that were identifiable in the NICU. Moreover, these sub-groups continued to differ on trajectories of distress and on their perceptions of the infants and parenting through 24 months after term. Originally published Journal of Developmental and Behavioral Pediatrics, Vol. 30, No. 3, June 200

Measuring and optimising the efficiency of community hospital inpatient care for older people: the MoCHA mixed-methods study

Background: Community hospitals are small hospitals providing local inpatient and outpatient services. National surveys report that inpatient rehabilitation for older people is a core function but there are large differences in key performance measures. We have investigated these variations in community hospital ward performance. Objectives: (1) To measure the relative performance of community hospital wards (studies 1 and 2); (2) to identify characteristics of community hospital wards that optimise performance (studies 1 and 3); (3) to develop a web-based interactive toolkit that supports operational changes to optimise ward performance (study 4); (4) to investigate the impact of community hospital wards on secondary care use (study 5); and (5) to investigate associations between short-term community (intermediate care) services and secondary care utilisation (study 5). Methods: Study 1 – we used national data to conduct econometric estimations using stochastic frontier analysis in which a cost function was modelled using significant predictors of community hospital ward costs. Study 2 – a national postal survey was developed to collect data from a larger sample of community hospitals. Study 3 – three ethnographic case studies were performed to provide insight into less tangible aspects of community hospital ward care. Study 4 – a web-based interactive toolkit was developed by integrating the econometrics (study 1) and case study (study 3) findings. Study 5 – regression analyses were conducted using data from the Atlas of Variation Map 61 (rate of emergency admissions to hospital for people aged ≥ 75 years with a length of stay of < 24 hours) and the National Audit of Intermediate Care. Results: Community hospital ward efficiency is comparable with the NHS acute hospital sector (mean cost efficiency 0.83, range 0.72–0.92). The rank order of community hospital ward efficiencies was distinguished to facilitate learning across the sector. On average, if all community hospital wards were operating in line with the highest cost efficiency, savings of 17% (or £47M per year) could be achieved (price year 2013/14) for our sample of 101 wards. Significant economies of scale were found: a 1% rise in output was associated with an average 0.85% increase in costs. We were unable to obtain a larger community hospital sample because of the low response rate to our national survey. The case studies identified how rehabilitation was delivered through collaborative, interdisciplinary working; interprofessional communication; and meaningful patient and family engagement. We also developed insight into patients’ recovery trajectories and care transitions. The web-based interactive toolkit was established [http://mocha. nhsbenchmarking.nhs.uk/ (accessed 9 September 2019)]. The crisis response team type of intermediate care, but not community hospitals, had a statistically significant negative association with emergency admissions. Limitations: The econometric analyses were based on cross-sectional data and were also limited by missing data. The low response rate to our national survey means that we cannot extrapolate reliably from our community hospital sample. Conclusions: The results suggest that significant community hospital ward savings may be realised by improving modifiable performance factors that might be augmented further by economies of scale. Future work: How less efficient hospitals might reduce costs and sustain quality requires further research

Depressive symptoms in the second trimester relate to low oxytocin levels in African-American women: a pilot study

Low-income African-American women report elevated prenatal depressive symptoms more often (42 %) than the national average (20 %). In the USA in 2012, 16.5 % of African-American women experienced a premature birth (less than 36 completed gestational weeks) compared to 10.3 % of white women. In addition, 13 % of African-American women had a low-birth weight infant (less than 2,500 g) compared to 7 % of white women. Variation in the neuropeptide, oxytocin has been implicated in perinatal depression, maternal behavior, regulation of stress responses, and may be associated with this health disparity. The purpose of this investigation was to examine factors associated with prenatal depressive symptoms, including plasma oxytocin levels and birth weight, in a sample of urban African-American women. Pregnant African-American women (N = 57) completed surveys and had blood drawn twice during pregnancy at 15-22 weeks and 25-37 weeks. In addition, birth data were collected from medical records. A large number of participants reported elevated prenatal depressive symptoms at the first (n = 20, 35 %) and the second (n = 19, 33 %) data points. Depressive symptoms were higher in multigravidas (t(51) = -2.374, p = 0.02), women with higher anxiety (r(47) = 0.71, p = 0.001), women who delivered their infants at an earlier gestational age (r(51) = -0.285, p = 0.04), and those without the support of the infant's father (F(4, 48) = 2.676, p = 0.04). Depressive symptoms were also higher in women with low oxytocin levels than in women with high oxytocin levels (F(2, 47) = 3.3, p = 0.05). In addition, women who had low oxytocin tended to have infants with lower birth weights (F(2, 47) = 2.9, p = 0.06). Neither prenatal depressive symptoms nor prenatal oxytocin levels were associated with premature birth. Pregnant multigravida African-American women with increased levels of anxiety and lacking the baby's father's support during the pregnancy are at higher risk for prenatal depressive symptoms. Prenatal depressive symptoms are associated with low oxytocin levels and lower infant birth weights. Further research is needed to understand the mechanisms between prenatal depressive symptoms, oxytocin, and birth weight in order to better understand this health disparity

Effects of Secondhand Smoke Exposure on the Health and Development of African American Premature Infants

Objective. To explore the effects of secondhand smoke exposure on growth, health-related illness, and child development in rural African American premature infants through 24 months corrected age. Method. 171 premature infants (72 boys, 99 girls) of African American mothers with a mean birthweight of 1114 grams. Mothers reported on household smoking and infant health at 2, 6, 12, 18, and 24 months corrected age. Infant growth was measured at 6, 12, 18, and 24 months, and developmental assessments were conducted at 12 and 24 months. Results. Thirty percent of infants were exposed to secondhand smoke within their first 2 years of life. Secondhand smoke exposure was associated with poorer growth of head circumference and the development of otitis media at 2 months corrected age. Height, weight, wheezing, and child development were not related to secondhand smoke exposure. Conclusion. Exposure to secondhand smoke may negatively impact health of rural African American premature infants. Interventions targeted at reducing exposure could potentially improve infant outcomes

Exploring Modifiable Risk Factors for Wheezing in African American Premature Infants

To examine the degree to which obesity during infancy, consistent exposure to secondhand smoke, and parenting (positive attention, maternal involvement, and negative control) were related to early development of wheezing in a cohort of African American premature infants at 2, 6, 12, 18, and 24 months corrected age

Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions

Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance

Risk Factors for Postpartum Depressive Symptoms in Low-Income Women With Very Low-Birth-Weight Infants

PURPOSE: This study examined factors associated with postpartum depressive symptoms in mothers with premature infants in the neonatal intensive care unit (NICU). SUBJECTS: A total of 113 new mothers with very low-birth-weight infants in their initial NICU admission were recruited from 2 urban hospitals servicing low-income minority communities. DESIGN: This study employed a cross-sectional design. METHODS: Data were collected during the infants' postpartum NICU admission and included maternal demographic information (eg, age, education, race, living with the baby's father), infant illness severity (Neurobiologic Risk Score from infant's medical record), and maternal psychological measures (the Center for Epidemiologic Studies Depression Scale, the Perinatal Posttraumatic Stress Questionnaire, and the State-Trait Anxiety Inventory). RESULTS: The findings indicated that 47 (42%) women had elevated postpartum depressive symptoms and 33 (30%) women had elevated postpartum posttraumatic stress symptoms (PTSs). Factors associated with postpartum depressive symptoms included PTS, anxiety, maternal age, and whether the mother lived with the baby's father (F₄, ₁₀₄ = 52.27, P < .001). The severity of the infants' illness, parental stress, and maternal education were not associated with depressive symptoms among low-income mothers of NICU infants. CONCLUSIONS: On the basis of our findings, we recommend that low-income women should be screened for symptoms of anxiety, posttraumatic stress, and postpartum depression on their infants' admission to the NICU. When this is not feasible, we advise NICU healthcare providers to assess women for familial support, maternal age, posttraumatic stress related to their infants birth, and anxiety to determine which mothers are at the greatest risk for postpartum depressive symptoms. Screening for postpartum depression in the NICU can aid in early identification and treatment, thereby decreasing negative consequences for mothers and their infants

An RCT of dating matters:Effects on teen dating violence and relationship behaviors

Introduction Teen dating violence is a serious public health problem with few effective prevention strategies. This study examines whether the Dating Matters comprehensive prevention model, compared with a standard of care intervention, prevented negative relationship behaviors and promoted positive relationship behaviors. Study design This longitudinal, cluster-RCT compared the effectiveness of Dating Matters with standard of care across middle school. Standard of care was an evidence-based teen dating violence prevention curriculum (Safe Dates) implemented in eighth grade. Setting/participants Forty-six middle schools in high-risk urban neighborhoods in four U.S. cities were randomized. Schools lost to follow-up were replaced with new schools, which were independently randomized (71% school retention). Students were surveyed in fall and spring of sixth, seventh, and eighth grades (2012–2016). The analysis sample includes students from schools implementing Dating Matters or standard of care for >2 years who started sixth grade in the fall of 2012 or 2013 and had dated (N=2,349 students, mean age 12 years, 49% female, and 55% black, non-Hispanic, 28% Hispanic, 17% other). Intervention Dating Matters is a comprehensive, multicomponent prevention model including classroom-delivered programs for sixth to eighth graders, training for parents of sixth to eighth graders, educator training, a youth communications program, and local health department activities to assess capacity and track teen dating violence–related policy and data. Main outcome measures Self-reported teen dating violence perpetration and victimization, use of negative conflict resolution strategies, and positive relationship skills were examined as outcomes. Imputation and analyses were conducted in 2017. Results Latent panel models demonstrated significant program effects for three of four outcomes; Dating Matters students reported 8.43% lower teen dating violence perpetration, 9.78% lower teen dating violence victimization, and 5.52% lower use of negative conflict resolution strategies, on average across time points and cohorts, than standard of care students. There were no significant effects on positive relationship behaviors. Conclusions Dating Matters demonstrates comparative effectiveness, through middle school, for reducing unhealthy relationship behaviors, such as teen dating violence and use of negative conflict resolution strategies, relative to the standard of care intervention