Capturing Low Probability of Disease Dynamics in Coupled Populations

Researchers using mathematical models have made significant contributions to the field of epidemiology in recent years. These models have both explanatory and predicative power to describe disease dynamics. More recent work has considered multi-population models and the effects vaccinations have on the population as a whole. One such example can be seen in the West African country of Cameroon, which has two distinct patterns of measles outbreaks. By considering Cameroon as two subpopulations, a deterministic model is developed that includes the effect of vaccinations. Stability analysis is then performed on the model over a range of coupling and vaccination rates to establish thresholds between disease absence and persistence. Stochastic methods are then used to capture low probability events near these thresholds. We identified significant differences in vaccination rates predicted deterministically for disease absence versus vaccination rates that are effective at inducing disease absence

The Impact of Coordination by a Child Abuse Committee on Community Services to Battered Children

The Child Abuse Committee at the University of Oregon Medical School has assumed a coordinating role as an attempt to provide more effective service to abused children and their families. This research report is a follow up to a 1970 study by Matusak which evaluated the effectiveness of the Committee. The Matusak study seemed to indicate that, because of Committee action resulting in appropriate intervention and services, definite improvement in the situation of the children in the study was seen. This study follows the children from the 1970 study one year later and makes further comparisons of child abuse cases seen at the hospital in 1971. The results of this study fail to support the Matusak findings. A decreased percentage of children in the 1970 study group have maintained their level of improvement one year later and an even lower percentage of the 1971 study group are improved. More children have been left in their own homes than in 1970 but there is little to indicate that the family functions any more adequately than at the time of abuse. The findings seem to reflect a need for reevaluation of management and treatment practices in child abuse cases. It appears that responsibility and authority for coordination should be placed with a single agency and that more specialized services be provided by experienced staff

Variations in supplier relations operating within voluntary groups: historical perspectives on relationships and social justice in the independent retail sector

The convenience store sector evolved from the variety of small retailers operating in the 1950’s and is still dominated (in store numbers) by SMEs operating smaller stores (usually smaller than 3,000 sq ft.); trading extended hours; with a base around confectionary, tobacco and news (CTN) and off licence. In the 1980s as more independent retailers adopted the new convenience format the convenience sector spread geographically to fill the increasing demand for local stores with extended hours. Once geographic saturation was reached the main independent supply chains within the convenience sector adopted either a broadly coordinated embedded network through voluntary symbol groups or a broadly cooperative supply chain through cash and carries and delivered wholesalers. Various writers have argued that networking and the building of social capital (as in the voluntary symbol groups) is vital for SME growth whilst Jack and Anderson (2002) have demonstrated that entrepreneurs embedding themselves within a network may be sacrificing their entrepreneurial capabilities. Around 2000, the major retail multiples and the COOP entered the convenience sector. By using their extensive knowledge of Supply Chain Management (SCM) they were able to gain commercial advantage over the existing supply chains which focused these chains on the need for economic efficiency. This meant that the businesses within the voluntary groups had to choose between the mechanisms highlighted by Payan (2000) of economic efficiency with increased dependence on the centre and the mechanisms of social justice within the group that allowed independent actions within the group. Possibly because of these mechanisms, distinct differences in the types of relationships started to appear between suppliers and independent retailers within each of the voluntary groups. New (1997) highlighted the two opposing forces facing independent retailers operating within voluntary groups; the drive for profit for the whole group and the desire for a perceived fair share of that profit for individual members of the group. This paper introduces work currently under way to investigate causal configurations of market forces and the social history of a sector that jointly dictate the relationship choices of SMEs within the supply chain. Envisaging a critical realist approach, the aim of the research is to develop understanding of current relationship choices and identify causal mechanisms that would explain how these choices affect independent retailers today

Resolution of the Distance Ambiguity for Galactic HII Regions

We resolve the kinematic distance ambiguity for 266 inner Galaxy HII regions out of a sample of 291 using existing HI and 13CO sky surveys. Our sample contains all HII regions with measured radio recombination line (RRL) emission over the extent of the 13CO Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey (18 deg, < l < 55 deg. and |b| < 1) and contains ultra compact, compact, and diffuse HII regions. We use two methods for resolving the distance ambiguity for each HII region: HI emission/absorption (HIEA) and HI self-absorption (HISA). We find that the HIEA and HISA methods can resolve the distance ambiguity for 72% and 87% of our sample, respectively. When projected onto the Galactic plane, this large sample appears to reveal aspects of Galactic structure, with spiral arm-like features at Galactocentric radii of 4.5 and 6 kpc, and a lack of HII regions within 3.5 kpc of the Galactic center. Our HII regions are approximately in the ratio of 2 to 1 for far verses near distances. The ratio of far to near distances for ultra-compact HII regions is 2.2 to 1. Compact HII regions are preferentially at the near distance; their ratio of far to near distances is 1.6 to 1. Diffuse HII regions are preferentially at the far distance; their ratio of far to near distances is 3.8 to 1. This implies that the distinction between ultra compact and compact HII regions is due largely to distance, and that the large angular size of diffuse HII regions is not due solely to proximity to the Sun.Comment: Accepted to Ap

Polyphenol-rich fruits attenuate impaired endothelial function induced by glucose and free fatty acids in vitro in human endothelial cells

Elevated concentrations of plasma glucose and free fatty acids (FFA) are associated with impaired endothelial function increasing risk of cardiovascular diseases. Previous studies suggested that fruits rich in polyphenolic compounds modulate endothelial cell migration and capillary-like tube formation via a redox-sensitive mechanism. We hypothesized that polyphenol-rich extracts of strawberry (SB) and wild blueberry (WB) would attenuate relatively high concentrations of glucose and/or FFA–mediated impaired cell migration and capillary-like tube formation in vitro in human umbilical vein endothelial cells (HUVECs). HUVECs treated with high FFA and combinations of glucose and FFA showed significantly reduced cell migration and capillary-like tube formation compared to the PBS control (p<0.05). However, HUVEC pre-treated with SB or WB extracts significantly increased cell migration and capillary-like tube formation in cells treated with FFA or a combination of FFA and glucose compared to cells exposed to the same nutrients/combinations alone. The results from this study suggest that berry fruits may play a role in promoting cardiovascular health especially in individuals with high blood glucose and/or FFA levels

Kinematic Distances to Molecular Clouds identified in the Galactic Ring Survey

Kinematic distances to 750 molecular clouds identified in the 13CO J=1-0 Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey (BU-FCRAO GRS) are derived assuming the Clemens rotation curve of the Galaxy. The kinematic distance ambiguity is resolved by examining the presence of HI self-absorption toward the 13CO emission peak of each cloud using the Very Large Array Galactic Plane Survey (VGPS). We also identify 21 cm continuum sources embedded in the GRS clouds in order to use absorption features in the HI 21 cm continuum to distinguish between near and far kinematic distances. The Galactic distribution of GRS clouds is consistent with a four-arm model of the Milky Way. The locations of the Scutum-Crux and Perseus arms traced by GRS clouds match star count data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) star-count data. We conclude that molecular clouds must form in spiral arms and be short-lived (lifetimes < 10 Myr) in order to explain the absence of massive, 13CO bright molecular clouds in the inter-arm space

Lorentz-Lorenz Coefficient, Critical Point Constants, and Coexistence Curve of 1,1-Difluoroethylene

We report measurements of the Lorentz-Lorenz coefficient density dependence, the critical temperature, and the critical density, of the fluid 1,1-difluoroethylene. Lorentz-Lorenz coefficient data were obtained by measuring refractive index and density of the same fluid sample independently of one another. Accurate determination of the Lorentz-Lorenz coefficient is necessary for transformation of refractive index data into density data from optics-based experiments on critical phenomena of fluid systems done with different apparatus, with which independent measurement of the refractive indes and density is not possible. Measurements were made along the coexistence curve of the fluid and span the density range 0.01 to 0.80 g/cc. The Lorentz-Lorenz coefficient results show a stronger density dependence along the coexistence curve than previously observed in other fluids, with a monotonic decrease from a density of about 0.2 g/cc onwards, and an overall variation of about 2.5% in the density range studied. No anomaly in the Lorentz-Lorenz coefficient was observed near the critical density. The critical temperature is measured at Tc=(302.964+-0.002) K (29.814 C) and the measured critical density is (0.4195+-0.0018)g/cc.Comment: 14 pages, 6 figures, MikTeX 2.4, submitted to Physical Review

Consequences of population change for local abundance and site occupancy of wintering waterbirds

Aim: Population size changes can lead to changes in local abundance and/or site occupancy, depending on the processes influencing site use by individuals. Here we quantify such changes for wintering waterbirds, and assess their implications for widely used conservation strategies in which sites that support in excess of a given proportion of a population are prioritised for protection.  Location: Britain. Methods: We use long-term survey data to quantify changes in population size and distribution for 19 waterbird species across Britain. Results: Population changes in these species have varied greatly (from declines of ~25% to increases of >1600%) over 26 years, and we show that change in local abundance was the predominant consequence of these changes, while colonisation of new sites mainly occurred in response to large population increases. For most species, changes in abundance and occupancy were spatially dependent over relatively short distances, consistent with (but not conclusive of) density-dependent spill-over. Levels of occupancy among species were negatively associated with proportions of sites, and populations within sites, exceeding the 1% of total population threshold for site protection. For species increasing in overall population size, the occurrence of small incipient populations at new sites resulted in declines in the number of sites supporting> 1% of the total population and the proportion of the population supported by these sites.  Main conclusions: Fluctuations in waterbird population size are more likely to result in changes in local abundance than distribution. Consequences of population change for site protection when abundance thresholds are used for site designation depend on shifts in the evenness of distribution of abundances across sites, and whether occupancy is increasing or decreasing. Range-expanding species have an increased likelihood of losing some sites, and populations within sites, exceeding the 1% of total population threshold for site protection