Markov model-based clustering for efficient patient care

Phase-type distributions were used to carry out model-based clustering of patients using the time spent by the patients in hospital, with maximum likelihood estimation of the model parameters. These parameters were allowed to vary with covariates so that the probability of cluster membership was dependent on these covariates. Expressions for the cluster membership probabilities and corresponding distributions of length of stay in care were found where the membership probabilities can be updated to take account of length of stay to date. The approach was applied to data on geriatric patients from an administrative database of a London hospital. The age of the patients at admission to care and the year of admission were included as covariates. Differential effects of these covariates on the various parameters of the fitted model were demonstrated, and interpretations of these effects made. The clusters here corresponded to patient pathways, with different length of stay distributions, varying care needs and different associated costs. By using the membership probabilities to assign patients to such clusters, care may thus be suited to their predicted pathway. Such an approach might be used in association with healthcare process improvement technologies, such as Lean Thinking or Six Sigm

Description and Vorticity Analysis of 50-Day Oscillations in the Western Tropical Region of the CME Model

The WOCE Community Modeling Effort (CME) general circulation model of the North Atlantic was used to investigate the behavior, nature, and dynamics of 50-day oscillations seen in the meridional component of velocity between 5 degrees and 11 degrees N, 35 degrees and 55 degrees W. Oscillations of the meridional component of velocity, with a period of about 50 days, appear as the seasonal meander pattern of the North Equatorial Countercurrent starts to break down in December. They appear first near 35 degrees W and are advected westward. They have a westward phase velocity of about 0.1 m s(-1), wavelength of about 600 km, and a very slow eastward group velocity. Their period, phase speed, and wavelength agree with recent observations. Calculation of the leading terms from the full vorticity equation following a modal decomposition in the propagation region showed that the oscillations were first and second mode baroclinic Rossby waves. Repetition of the vorticity analysis on an undecomposed snapshot during the period of the retroflection revealed the NECC meanders also to be baroclinic Rossby waves, the same as the 50-day oscillations. These findings, together with the time evolution of the individual flow components over an annual cycle, suggested that the 50-day oscillations were the westward advected residue of the NECC meander pattern that is released as the NECC slows in December. The retroflecting North Brazil Current produces Rossby waves with very slow eastward group velocity that are advected eastward by the NECC until they reach 35 degrees W, where they dissipate. A standing wave pattern is established for several months, while the NECC is active. Once it slows, the waves are advected westward and disappear totally by May. Neither wind forcing nor barotropic instability were considered to be responsible for the oscillations in the model

The effect of farming system on dairy cow cleanliness in the UK and implications to udder health

The cleanliness of dairy cows was assessed using a 20 point hygiene score system at different times in the year on 14 organic and 14 conventional farms in the UK. Overall, cows were dirtier during winter housing compared to summer grazing. Farming system had no effect on cow cleanliness when cows were at grass, but when housed in the winter, organic cows were more likely to be cleaner. There was a link between cow hygiene scores and milk hygiene, with herds having lower bulk tank somatic cell counts (BTSCC) tending to have cleaner cows. This relationship was strongest for the organic herds. There was no significant link between hygiene score and Bactoscan (BS) count or mastitis incidence

Urinary naphthalene and phenanthrene as biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The study investigated the utility of unmetabolised naphthalene (Nap) and phenanthrene (Phe) in urine as surrogates for exposures to mixtures of polycyclic aromatic hydrocarbons (PAHs). METHODS: The report included workers exposed to diesel exhausts (low PAH exposure level, n = 39) as well as those exposed to emissions from asphalt (medium PAH exposure level, n = 26) and coke ovens (high PAH exposure level, n = 28). Levels of Nap and Phe were measured in urine from each subject using head space-solid phase microextraction and gas chromatography-mass spectrometry. Published levels of airborne Nap, Phe and other PAHs in the coke-producing and aluminium industries were also investigated. RESULTS: In post-shift urine, the highest estimated geometric mean concentrations of Nap and Phe were observed in coke-oven workers (Nap: 2490 ng/l; Phe: 975 ng/l), followed by asphalt workers (Nap: 71.5 ng/l; Phe: 54.3 ng/l), and by diesel-exposed workers (Nap: 17.7 ng/l; Phe: 3.60 ng/l). After subtracting logged background levels of Nap and Phe from the logged post-shift levels of these PAHs in urine, the resulting values (referred to as ln(adjNap) and ln(adjPhe), respectively) were significantly correlated in each group of workers (0.71 < or = Pearson r < or = 0.89), suggesting a common exposure source in each case. Surprisingly, multiple linear regression analysis of ln(adjNap) on ln(adjPhe) showed no significant effect of the source of exposure (coke ovens, asphalt and diesel exhaust) and further suggested that the ratio of urinary Nap/Phe (in natural scale) decreased with increasing exposure levels. These results were corroborated with published data for airborne Nap and Phe in the coke-producing and aluminium industries. The published air measurements also indicated that Nap and Phe levels were proportional to the levels of all combined PAHs in those industries. CONCLUSION: Levels of Nap and Phe in urine reflect airborne exposures to these compounds and are promising surrogates for occupational exposures to PAH mixtures

A Comparative Analysis of Mortuary and Domestic Artifacts from Petra’s North Ridge

Interpreting the use of material culture in mortuary contexts provides an intimate view of the social identity of both the deceased and the mourners in ancient societies. However, the material remains of mortuary practices throughout the Nabataean Kingdom (3rd century BC – 2nd century AD) have not been sufficiently investigated. Qualitative and quantitative comparisons of the material culture between contemporary mortuary and domestic contexts will establish a preliminary characterization of uniquely mortuary material culture and highlight objects that have a dual purpose within both spaces. This study focuses on the small finds from occupational or mortuary layers from at least four domestic complexes and five rock-cut shaft chamber tombs located on Petra’s North Ridge dating to the 2nd century BC to the 2nd century AD. Through quantitative and qualitative analyses of the small finds, we found that jewelry items, grinding stones, spindle whorls, figurines, coins, lamps, and lids were found in both contexts, but these artifact types may be more abundant in one context than another. Alternatively, game pieces, scarabs, incense altars, votive carvings and coffin studs are specific to mortuary contexts, while pestles, spindles, and spoons were solely found in domestic contexts. Therefore, this research will provide insight into the social organization and identity of the community living on the North Ridge and shed light on Nabatean views of death, mourning, and the treatment of the deceased

The worldwide costs of marine protected areas

Declines in marine harvests, wildlife, and habitats have prompted calls at both the 2002 World Summit on Sustainable Development and the 2003 World Parks Congress for the establishment of a global system of marine protected areas (MPAs). MPAs that restrict fishing and other human activities conserve habitats and populations and, by exporting biomass, may sustain or increase yields of nearby fisheries. Here we provide an estimate of the costs of a global MPA network, based on a survey of the running costs of 83 MPAs worldwide. Annual running costs per unit area spanned six orders of magnitude, and were higher in MPAs that were smaller, closer to coasts, and in high-cost, developed countries. Models extrapolating these findings suggest that a global MPA network meeting the World Parks Congress target of conserving 20–30% of the world’s seas might cost between $5 billion and$19 billion annually to run and would probably create around one million jobs. Although substantial, gross network costs are less than current government expenditures on harmful subsidies to industrial fisheries. They also ignore potential private gains from improved fisheries and tourism and are dwarfed by likely social gains from increasing the sustainability of fisheries and securing vital ecosystem services

A Systematic Review of the Acute Effects of Exercise on Immune and Inflammatory Indices in Untrained Adults

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of global mortality. Although the incidence may be reduced with regular exercise, the health benefits of a single bout of exercise on selected CVD risk factors are not well understood. The primary objective of this review is to consider the transient effects of exercise on immune (neutrophil count) and inflammatory (interleukin-6 [IL-6], C-reactive protein [CRP]) markers in untrained adults. METHODS: MEDLINE, EMBASE, CINAHL, Sports Discus and Cochrane were searched for relevant studies published from January 1946 to May 2013. Randomised controlled or crossover studies which measured any of these parameters in untrained but otherwise healthy participants in the 48 h following about of exercise, less than 1 h in duration were included. RESULTS: Ten studies met the inclusion criteria. The results indicate a single bout of aerobic or resistance exercise of moderate to high intensity promotes an increase in IL-6 (145 %) and neutrophil counts (51 %). It appears that 30–60 min of moderate to high intensity exercise is necessary to elicit such changes although variables such as the mode, intensity and pattern of exercise also affect the response. The acute response of CRP within the included studies is equivocal. CONCLUSIONS: Although responses to CRP are inconsistent, a single bout of exercise can increase the activity of both circulating IL-6 and neutrophil counts in untrained adults. These immune and inflammatory responses to a single bout of exercise may be linked to a range of health benefits