Parallel hierarchical sampling:a general-purpose class of multiple-chains MCMC algorithms

This paper introduces the Parallel Hierarchical Sampler (PHS), a class of Markov chain Monte Carlo algorithms using several interacting chains having the same target distribution but different mixing properties. Unlike any single-chain MCMC algorithm, upon reaching stationarity one of the PHS chains, which we call the “mother” chain, attains exact Monte Carlo sampling of the target distribution of interest. We empirically show that this translates in a dramatic improvement in the sampler’s performance with respect to single-chain MCMC algorithms. Convergence of the PHS joint transition kernel is proved and its relationships with single-chain samplers, Parallel Tempering (PT) and variable augmentation algorithms are discussed. We then provide two illustrative examples comparing the accuracy of PHS with

Feeding practices and growth among young children during two seasons in rural Ethiopia

BACKGROUND: The use of indices of infant and young child feeding practices to predict growth has generated inconsistent results, possibly through age and seasonal confounding. The aim of this study was to evaluate the association of a dietary diversity score (DDS) and infant and child feeding index (ICFI) with growth among young children in a repeated cross-sectional and a follow-up study in two distinct seasons in rural southwest Ethiopia. METHODS: We used a repeated cross-sectional design comparing child feeding practices to nutritional status in 6–12 month old children during harvest (HS; n = 320) and pre-harvest season (PHS; n = 312). In addition, 6–12 month old children from the HS were reassessed 6 months later during PHS. In addition to child anthropometry, child feeding practices were collected using 24-h and 7-day dietary recalls. RESULTS: The mean (±SD) length-for-age z-score (LAZ) of the 6–12 month old children was −0.77 (±1.4) and −1.0 (±1.3) in HS and PHS, respectively, while the mean (±SD) of the follow-up children in PHS was −1.0 (±1.3). The median DDS (IQR) was 2.0 (1.0, 3.0.), 2.0 (2.0, 3.0) and 3.0 (2.0, 4.0) for the children in HS, PHS and the follow-up children in PHS, respectively. The DDS in HS was positively associated with LAZ at follow-up (β = 0.16; 95% CI: 0.01, 0.30; P = 0.03) after controlling for confounding factors. ICFI and DDS were not associated with mean LAZ, weight-for-height z-score and weight-for-age z-score within season. However, the odds of being stunted when having a DDS ≤ 2 was 2.3 times (95% CI: 1.10, 4.78; P = 0.03) higher compared to a DDS > 2 child in HS and 1.7 times (95% CI: 1.04, 2.71; P = 0.04) higher for the pooled sample of 6–12 months old children in HS and PHS. CONCLUSIONS: The DDS was found to be an indicator for child stunting during the Ethiopian harvest season. The DDS can be an appropriate tool to evaluate the association of child feeding practices with child growth irrespective of season. Inclusion of other dimensions in the construction of ICFI should be considered in future analysis as we found no association with growth

Student-Centered Learning Opportunities For Adolescent English Learners In Flipped Classrooms

This study documents opportunities for diverse adolescent English learners to deeply engage with content and language in flipped learning environments. Through a linked description of teaching practices and student learning experiences in an urban New England high school, the study attempts to understand the potential of flipped instruction in preparing a traditionally underserved population for post-secondary education. Our research partner Patriot High School (PHS) is one of the New England schools implementing flipped learning. PHS represents a typical secondary school context for adolescent English learners: More than half of students speak a language other than English at home and the majority of students are from minority and low-income homes (Massachusetts Department of Elementary and Secondary Education, 2014). PHS is also an urban school committed to implementing student-centered learning strategies to meet the needs of its diverse students

Spatial distribution of trace metals in urban soils and road dusts : an example from Manchester, UK

Urban soil quality is of concern under current UK contaminated land legislation in terms of potential impacts on human health, due to the legacy of industrial, mining and waste disposal activities and the fact that soils can act as a sink for potentially harmful substances (PHS) in the urban environment. As part of the the Geochemical Baseline Survey of the Environment (G-BASE) project of the British Geological Survey (BGS), 27 UK cities have been surveyed to establish baselines and assess the quality of urban soils. The G-BASE soil geochemical dataset for Manchester forms the basis of this project. Another medium that is a likely sink for PHS in urban environments is road dust sediment (RDS). RDS forms as an accumulation of particles on pavements and road surfaces, and has been shown to be both spatially and temporally highly variable in composition, as it is more susceptible to remobilisation and transport. RDS has been documented as carrying a high loading of contaminant species, including significant amounts of trace metals. Geochemical data from both soils and RDS, despite having different properties, are essential for environmental assessment in urban areas. Although studies of PHS in RDS and soils have been published, little is known about the spatial, geochemical and mineralogical linkages between these two media. The aim of this research is to define and establish these linkages, and produce novel mineralogical data on the PHS–particulate relationships within soils and RDS

Public Health Informatics in Local and State Health Agencies: An Update From the Public Health Workforce Interests and Needs Survey

OBJECTIVE: To characterize public health informatics (PHI) specialists and identify the informatics needs of the public health workforce. DESIGN: Cross-sectional study. SETTING: US local and state health agencies. PARTICIPANTS: Employees from state health agencies central office (SHA-COs) and local health departments (LHDs) participating in the 2017 Public Health Workforce Interests and Needs Survey (PH WINS). We characterized and compared the job roles for self-reported PHI, "information technology specialist or information system manager" (IT/IS), "public health science" (PHS), and "clinical and laboratory" workers. MAIN OUTCOME MEASURE: Descriptive statistics for demographics, income, education, public health experience, program area, job satisfaction, and workplace environment, as well as data and informatics skills and needs. RESULTS: A total of 17 136 SHA-CO and 26 533 LHD employees participated in the survey. PHI specialist was self-reported as a job role among 1.1% and 0.3% of SHA-CO and LHD employees. The PHI segment most closely resembled PHS employees but had less public health experience and had lower salaries. Overall, fewer than one-third of PHI specialists reported working in an informatics program area, often supporting epidemiology and surveillance, vital records, and communicable disease. Compared with PH WINS 2014, current PHI respondents' satisfaction with their job and workplace environment moved toward more neutral and negative responses, while the IT/IS, PHS, and clinical and laboratory subgroups shifted toward more positive responses. The PHI specialists were less likely than those in IT/IS, PHS, or clinical and laboratory roles to report gaps in needed data and informatics skills. CONCLUSIONS: The informatics specialists' role continues to be rare in public health agencies, and those filling that role tend to have less public health experience and be less well compensated than staff in other technically focused positions. Significant data and informatics skills gaps persist among the broader public health workforce

Policy options for obesity in Europe: a comparison of public health specialists with other stakeholders

Objective: To explore policy options that public health specialists (PHS) consider appropriate for combating obesity in Europe, and compare their preferences with those of other stakeholders (non-PHS). Design: Structured interviews using multicriteria mapping, a computer-based, decision-support tool. Setting: Nine European countries. Subjects: A total of 189 stakeholders. Twenty-seven interviewees were PHS and non-PHS included food, sports and health sectors. Measurements: A four-step approach was taken, i.e. selecting options, defining criteria, scoring options quantitatively and weighting the criteria to provide overall rankings of options. Interviews were recorded and transcribed to yield qualitative data. Results: The PHS concur with other stakeholders interviewed, as all emphasised the importance of educational initiatives in combating obesity, followed by policies to improve community sports facilities, introduce mandatory food labelling and controlling food and drink advertising. Further analyses revealed several significant differences. The non-PHS from the private sector ranked institutional reforms favourably; the PHS from non-Mediterranean countries supported the option of medicines to prevent obesity; and those PHS from Mediterranean countries endorsed the use of activity monitoring devices such as pedometers. As far as appraisal criteria were concerned, PHS considered efficacy and the economic impact on the public sector to be the most important. Conclusion: There is clear consensus among PHS and other stakeholders concerning the need for a package of policy options, which suggests that European-wide implementation could be successful. However, it would be advisable to avoid more contentious policy options such as taxation until future changes in public opinion.New and Emerging Science and Technology (NEST) research programme (European Union)

Partial Exchange Transfusion For Polycythemia Hyperviscosity Syndrome

PARTIAL EXCHANGE TRANSFUSION FOR POLYCYTHEMIA HYPERVISCOSITY SYNDROME: A 21-YEAR REVIEW Bridget L. Hopewell, Laurie A. Steiner, Richard A. Ehrenkranz, Matthew J. Bizzarro, and Patrick G. Gallagher. Division of Perinatal Medicine, Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut. The objective of this study was to examine the use of partial exchange transfusion (PET) performed for polycythemia hyperviscosity syndrome (PHS) over time. A retrospective review of 141 infants who received a PET for PHS at Yale-New Haven Hospital, between 1986-2007 was performed, querying maternal and neonatal medical records. Patient demographics, risk factors for PHS, indications for PET, and complications associated with PET and PHS were collected. Overall, there was no change in the number of PET performed over the study period (r2=0.082, p=0.192). Eighty-eight percent of patients had at least one risk factor for PHS, most commonly maternal diabetes. Over time, there was a statistically significant decrease in maternal diabetes as a risk factor for PHS. Forty percent of patients had a significant complication attributed to PHS prior to PET. Eighteen percent of patients had a complication attributed to PET. Life-threatening complications of PHS or PET were rare. In conclusion, PHS continues to be a problem observed in neonatal intensive care units, particularly in at-risk populations. PHS and PET are associated with significant complications. Well designed studies with long-term follow up are needed to assess the risks and benefits of PET for PHS

Discrete-time port-Hamiltonian systems: A definition based on symplectic integration

We introduce a new definition of discrete-time port-Hamiltonian systems (PHS), which results from structure-preserving discretization of explicit PHS in time. We discretize the underlying continuous-time Dirac structure with the collocation method and add discrete-time dynamics by the use of symplectic numerical integration schemes. The conservation of a discrete-time energy balance - expressed in terms of the discrete-time Dirac structure - extends the notion of symplecticity of geometric integration schemes to open systems. We discuss the energy approximation errors in the context of the presented definition and show that their order is consistent with the order of the numerical integration scheme. Implicit Gauss-Legendre methods and Lobatto IIIA/IIIB pairs for partitioned systems are examples for integration schemes that are covered by our definition. The statements on the numerical energy errors are illustrated by elementary numerical experiments.Comment: 12 pages. Preprint submitted to Systems & Control Letter