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In this paper we describe several approaches to the AUV (glider) mission planning problem and investigate their complexity. At the heart of such mission planning are variants of an NP-hard (Non-deterministic Polynominal-time) Asymmetric Travelling Salesman Problem (ATSP); however, some modern-day heuristics can solve this problem optimally in a reasonable amount of time (although providing a proof of optimality slows down the computation). A glider mission plan often has to accommodate a variety of other constraints such as scheduling restrictions, specific time windows or order to visit selected points and so on. Here we consider a general AUV mission planning problem which, although based on ATSP, can incorporate other constraints. Thus, the use of general-purpose solvers such as Integer Linear Programming or Satisfiability-based solvers may be desired. With this goal, we have developed a software package for the glider mission planning problem that utilizes a variety of existing solvers to compute an optimal order of goal points to visit, subject to travel time as well as userprovided additional constraints. Then, to evaluate feasibility of this setting using state-of-the-art solvers, we analyze the performance of a variety of solvers on the core ATSP problem. [ABSTRACT FROM AUTHOR]

This article describes the development of a ward accreditation scheme that was set up to tackle healthcare associated infection in an acute trust. The scheme was used on all inpatient wards, and early reports indicated significant variation in practice. Standardisation of practice and regular audit has resulted in a 35.6% reduction in MRSA over a 12 month period.

The mortality experience of 7,119 workers who were employed at a Beaumont, Texas, refinery for at least 1 year between 1945 and 1987 was investigated. Mortality analyses based on standardized mortality ratios (SMRs) and 95% confidence intervals (95% CI) showed overall mortality was significantly lower than expected compared with the U.S. general population (SMR = 82, 95% CI = 79-86). Total cancer mortality was also lower than expected (SMR = 92, 95% CI = 84-100). Significant mortality deficits from several malignant and nonmalignant diseases were reported. A significant mortality increase in the broad category of lymphatic and hematopoietic cancers was found (SMR = 133, 95% CI = 103-170). This increase was attributed to a nonsignificant elevation in leukemia of all cell types combined (SMR = 139, 95% CI = 92-201) and a borderline significant increase in other lymphatic tissue cancer (SMR = 158, 95% CI = 101-235). The elevation in leukemia was confined to workers hired before 1950. Furthermore, the leukemia excess was shown to have peaked during the 1960s, with mortality no longer elevated post-1980. Analyses of cell type-specific leukemias showed a similar temporal pattern for acute myeloid leukemia (AML) which was not significantly elevated (SMR = 136, 95% CI = 59-268). Mortality from other leukemia cell types was similar to or lower than expected. Mortality from non-Hodgkin's lymphoma (NHL) (SMR = 140, 95% CI = 88-211) and multiple myeloma (MM) (SMR = 121, 95% CI = 55-230) were increased, but neither was statistically significant nor likely to be related to refinery employment. No death from asbestosis was reported, and mortality from mesothelioma and pulmonary fibrosis was lower than expected. Lung cancer mortality for the overall cohort was similar to expected. For the overall cohort, analyses by duration of employment and time since first employment showed no evidence of any trends for increasing cause-specific mortality. Separate analyses of male workers employed in operator jobs showed mortality patterns that were more favorable than those of the total cohort. Maintenance craftworkers showed statistically significant elevations in mortality for prostate cancer (SMR = 145, 95% CI = 107-194), leukemia (SMR = 179, 95% CI = 111-273), and other lymphatic tissue cancer (SMR = 233, 95% CI = 138-368). Detailed analyses indicated that, among maintenance craftworkers, mortality was elevated for AML, NHL, and MM, but none was significant. Furthermore, no upward trend by duration of maintenance jobs was observed. A small increase of lung cancer was observed among maintenance craftworkers (SMR = 120, 95% CI = 99-145), which was borderline significant. No relationship between lung cancer and duration of maintenance employment was found. In contrast, a deficit of pulmonary fibrosis was reported among maintenance craftworkers (SMR = 62, 95% CI = 17-159). These findings are discussed in conjunction with results from other refinery studies, and the limitations of the study are discussed.

This retrospective cohort mortality study examined 2,467 workers in lubrication products blending and packaging (B&P) operations at two refineries of Mobil Corporation between January 1, 1945 and December 31, 1978. Ninety-seven percent were male. Compared with U.S. males, there were significantly fewer deaths observed among males due to all causes, external causes, and diseases of the circulatory, respiratory, digestive, and genitourinary systems. Deaths observed from all cancer were fewer than expected, although not statistically significant. No statistically significant excess cause-specific mortality occurred at B&P facilities combined or separately. Nonsignificant increases in mortality were observed for cancers of the stomach, large intestine, prostate, the category of "other lymphatic tissue" cancer, and leukemia and aleukemia. Analyses demonstrated a statistically significant pattern of increasing SMR with employment duration for "other lymphatic tissue" cancer. Within the highest cumulative duration of employment category, the excess was confined to workers after 30 or more years since first employment. Although the interpretation of cancer mortality patterns is limited due to small numbers of deaths, the absence of associations with specific B&P departments is evidence against a causal interpretation.

Since lymphocyte nuclear size and shape play such a key role in the classification of non-Hodgkin's lymphoma (NHL), the mechanisms and nuclear compartments responsible for the control of nuclear size are of fundamental importance to pathologists. To assess the role of condensed chromatin and the interchromatinic region of the nucleus in determining the size of this organelle, morphometric image analysis of total nuclear area and the area occupied by these two compartments was performed on electron micrographs of nuclear profiles from lymphocytes in lymph node biopsies of four cases of reactive lymphoid hyperplasia and ten examples of NHL. Using bivariate linear regression analysis, it was clear that, whether in normal mantle zone and follicular center lymphocytes or in the neoplastic lymphocytes of various NHLs, there is an extremely high correlation (R = 0.96) between the size of the interchromatinic region and the area of nuclear profiles. In contrast, there is a poorer correlation (R = 0.63) between the area occupied by condensed chromatin and nuclear area. The results demonstrate for the first time that even in NHL, where some nuclear features clearly vary from the normal counterpart, the control of nuclear size continues to be largely dependent on a particular subcompartment of the nucleus, the interchromatinic region. How this fact influences the categorization of subtypes of NHL for therapeutic and prognostic purposes will be an essential avenue for further investigation.

An industry-wide retrospective cohort mortality study was conducted on 6,152 chemical workers (2,460 exposed and 3,692 nonexposed) engaged in chloromethyl ether manufacture at 7 major U.S. companies between 1948 and 1980. A previous study at 6 companies from 1948 through 1972 reported excess respiratory cancer (RC) mortality and significant exposure-response relationships in exposed workers at 1 company (company 2). The present study, which extended follow-up of an additional 7 years for companies 1-6 and included company 7 for follow-up from 1953 through 1980, found excess RC mortality in exposed workers at company 2 [observed (Obs) = 32, standardized mortality ratio (SMR) = 430] and company 7 (Obs = 9, SMR = 603). External comparisons of RC mortality at both companies showed significant exposure-response relationships with respect to cumulative time-weighted exposure. At company 2, where the greatest number of RC deaths occurred, external comparisons showed that RC risk remained constant in relation to age at first exposure and decreased with increasing time since last exposure. With the use of Mantel-Haenszel and relative risk (RR) regression methods, internal comparisons at company 2 demonstrated significant findings of increasing RR with cumulative duration of exposure and cumulative time-weighted exposure and with decreasing time since last exposure. No association was found between RR and age at first exposure. An interesting finding was a significant negative interaction between cumulative time-weighted exposure and age at risk. The best-fitting logistic regression model for the exposed group predicted RR at 2.79 (95% confidence interval = 1.66-4.69) for workers with the mean cumulative exposure score of the 32 RC deaths (lagged by 6 yr) compared with those with negligible exposure (assuming mean age at risk of the RC deaths, 51 years old, and time since last exposure held constant). Qualitative assessment of the results suggests that chloromethyl ether exposure affects both an early as well as a late stage of a putative multistage respiratory malignant process.