Image coding using depth blurring for aesthetically acceptable distortion.

We introduce the concept of depth-based blurring to achieve an aesthetically acceptable distortion when reducing the bitrate in image coding. The proposed depth-based blurring is a prefiltering that reduces high-frequency components by mimicking the limited depth of field effect that occurs in cameras. To cope with the challenge of avoiding intensity leakage at the boundaries of objects when blurring at different depth levels, we introduce a selective blurring algorithm that simulates occlusion effects as occur in natural blurring. The proposed algorithm can handle any number of blurring and occlusion levels. Subjective experiments show that the proposed algorithm outperforms foveation filtering, which is the dominant approach for bitrate reduction by space-variant prefiltering.

Accurate and efficient method for smoothly space-variant Gaussian blurring.

This paper presents a computationally efficient algorithm for smoothly space-variant Gaussian blurring of images. The proposed algorithm uses a specialized filter bank with optimal filters computed through principal component analysis. This filter bank approximates perfect space-variant Gaussian blurring to arbitrarily high accuracy and at greatly reduced computational cost compared to the brute force approach of employing a separate low-pass filter at each image location. This is particularly important for spatially variant image processing such as foveated coding. Experimental results show that the proposed algorithm provides typically 10 to 15 dB better approximation of perfect Gaussian blurring than the blended Gaussian pyramid blurring approach when using a bank of just eight filters.

Metalworking fluid mist--strategies to reduce exposure: a comparison of new and old transmission case transfer lines.

Three studies were performed to assess the effectiveness of various techniques to control metalworking fluid (MWF) mist. The studies consisted of a detailed main study that determined the effect of degree of enclosure on personal exposures and area concentrations of MWF mist on two machining transfer lines. One ancillary study was conducted to determine the effect of shutting off MWF delivery during down time; the second ancillary study investigated the effectiveness of improved retrofitted enclosure. In the main study, the two operations were identical except for degree of enclosure. Personal and area sampling results for the new line were about half those found in the old line. Measurements at the new operation exhibited significantly less variability. Personal exposures and area concentrations were significantly less at the new operation than at the older, less enclosed operation, demonstrating that the total enclosure in the new operation provides better and more consistent control of the mist. The first ancillary study was conducted to determine if shutting off MWF delivery to the parts being machined reduced area MWF mist concentration during downtime at a partially enclosed transfer machining line. A significant reduction in concentration of 80% was measured with machining off/MWF off. Mist concentrations measured with machining off/MWF on were not significantly different from mist levels measured during machining on/MWF on. The second ancillary study investigated the reduction of mist concentration achieved through improved enclosure of an existing set of machines. Area mist concentrations were measured at a machining operation before and after the installation of an improved enclosure. Area mist concentrations were reduced by 87% with the improved enclosure.

Practical asymmetric synthesis of a gamma-secretase inhibitor exploiting substrate-controlled intramolecular nitrile oxide-olefin cycloaddition.

A practical asymmetric synthesis of the gamma-secretase inhibitor (-)-1 is described. As the key transformation, a highly diastereoselective intramolecular nitrile oxide cycloaddition forms the hexahydrobenzisoxazole core of 3 in four operations. Other aspects of the route include a highly stereoselective reduction of an isoxazole to form a cis-gamma-amino alcohol, an efficient chemical resolution, a dianion cyclization to construct a sultam ring, and the alpha-alkylation of a sultam with excellent diastereoselectivity. In each instance, the relative stereochemistry was evolved by way of substrate-based induction with > or = 96% ds. Kilogram quantities of the targeted drug candidate (-)-1 were obtained, without recourse to chromatography, by way of 10 isolated intermediates and in 13% overall yield.

Control methods for mineral oil mists.

Effective mist collection is important, but it is not the only determinant of mist concentration in plant air. Oil-based metalworking fluids such as straight and soluble oils contain semivolatile hydrocarbons. When these fluids form a mist, their semivolatile components partition between the vapor and mist phases depending on the makeup of the mist and on local conditions. This article addresses the relationship between the concentrations of semivolatile hydrocarbons in the vapor and mist phases using theory for partitioning developed in the field of atmospheric chemistry. Mist can be removed effectively in a collector that uses a HEPA filter as its final collection stage. Acceptable HEPA lifetime requires effective upstream stages that reduce mist loading to the HEPA; furthermore, acceptable HEPA performance requires that it be installed and maintained properly. Collectors designed to remove mist do not remove vapor, and as collector exhaust mixes into cooler plant air that already contains some mist, vapor from the collector can repartition to increase the mist concentration in the plant. Assessing the effect of vapor-to-mist repartitioning is complicated; however, repartitioning may be important for many of the compounds contained in oil-based metalworking fluids. Conditions that minimize vapor-to-mist repartitioning, such as ventilating the plant with clean outdoor air, increasing plant temperature, or controlling the release of vapor, may also be expensive, uncomfortable to plant occupants, or impractical from an engineering standpoint. As a result, very low mist concentrations in plant air may be difficult to attain.

Inpatient hospital admission rates for nonmalignant respiratory disease among workers exposed to metal removal fluids at a U.S. automobile manufacturer.

This study was undertaken to determine the impact of exposure to metal removal fluids (MRFs) on the respiratory health of exposed workers. The outcome measure selected was the rate of hospital admissions for nonmalignant respiratory disease episodes as determined from healthcare insurance claims data. A cohort of MRF-exposed employees was assembled from 11 manufacturing facilities where MRFs were extensively used in the manufacture of automotive engines, transmissions, and other machined parts. The MRF-exposed cohort included 20,434 employees of such facilities who worked at any time from 1993 through 1997. A non-MRF-exposed cohort was assembled from other employees of the same company during the same time period, but working in warehouse operations and other manufacturing facilities that did not use MRFs or any known respiratory sensitizing agents. The non-exposed cohort included 8681 employees. The crude hospital admission rate for the MRF-exposed cohort was 44 percent higher than that of the non-exposed cohort over the 5-year study period (6.67 vs. 4.62 per 1000 person years at risk, p < 0.05). With age adjustment, the MRF population's rate was still 35 percent higher, and still statistically significant. A nested case-control study was also conducted to determine whether the risk of hospital admission increased with the level of MRF exposure in the population working in MRF plants. The industrial hygiene reconstruction found the levels of exposures of both cases and controls to be very low, with the vast majority of study subjects (more than 90%) having exposures of less than 0.5 mg/m(3). The case-control study did not find any association between increased levels of MRF exposure and risk of hospitalization. The study did document an elevated risk of hospitalization among a sizable population employed in manufacturing operations where MRFs are used.

A systematic review of the clinical and economic impact of drug information services on patient outcome.

AIM: To establish what is known about the clinical and economic impact of drug information (DI) services on patient outcome. METHOD: A systematic review and critical appraisal of world literature on work conducted by Drug Information Centres and UK Schools of Pharmacy. RESULTS: Six relevant published articles were recovered--three from the UK; two from the US and one from Canada; just one was prospective in design. Four were single-centre and two were multi-centre studies. Four studies relied heavily on questionnaire surveys of the enquirer to establish an effect; only one monitored patient outcome independently and used peer review to assess impact. CONCLUSION: The clinical and economic impact of drug information consultation and provision on patient care has not been investigated rigorously. A research methodology for such an investigation is suggested.

Victorian values and mental health nursing.

It was disappointing to read the article on mental health nursing featured in the Appointments section because it gave no indication of the positive side of those large psychiatric institutions (Mental health nursing, June 29).