A meshing scheme for efficient hardware implementation of butterfly subdivision using displacement mapping

Displacement mapping is an effective technique for encoding the high levels of detail of surface models using coarse triangle meshes and displacement maps. These maps are 2D representations containing the distances between the coarse mesh and the surface to represent. Displacement maps have been used in many applications such as ray tracing, image warping, and volume rendering. In this article, we propose modifications to our previous grouping strategy, a new subdivision strategy based on the Modified Butterfly algorithm and new heuristics for the adaptive subdivision procedure, and, finally, the corresponding modifications on our hardware proposal. A meshing scheme and an adaptive subdivision strategy based on displacement mapping reduce the bottleneck between the CPU and graphics pipeline common in high-performance graphics systems.     

Isolation of the [3H]gabapentin-binding protein/alpha 2 delta Ca2+ channel subunit from porcine brain: development of a radioligand binding assay for alpha 2 delta subunits using [3H]leucine

Mutations in a number of genes affect eye colour in Drosophila melanogaster; some of these "eye-colour" genes have been shown to be involved in various aspects of cellular transport processes. In addition, combinations of viable mutant alleles of some of these genes, such as carnation (car) combined with either light (lt) or deep-orange (dor) mutants, show lethal interactions. Recently, dor was shown to be homologous to the yeast gene PEP3 (VPS18), which is known to be involved in intracellular trafficking. We have undertaken to extend our earlier work on the lt gene, in order to examine in more detail its expression pattern and to characterize its gene product via sequencing of a cloned cDNA. The gene appears to be expressed at relatively high levels in all stages and tissues examined, and shows strong homology to VPS41, a gene involved in cellular-protein trafficking in yeast and higher eukaryotes. Further genetic experiments also point to a role for lt in transport processes: we describe lethal interactions between viable alleles of lt and dor, as well as phenotypic interactions (reductions in eye pigment) between allels of lt and another eye-colour gene, garnet (g), whose gene product has close homology to a subunit of the human adaptor complex, AP-3.     

Subretinal semiconductor microphotodiode array

OBJECTIVE: To evaluate the predictive validity of the Emergency Physician Job Satisfaction (EPJS) and Global Job Satisfaction (GJS) instruments. METHODS: Prospective mail survey of 223 Canadian emergency physicians (EPs) using a 42-item questionnaire, including 14 items evaluating their reasons for leaving emergency medicine (EM). Original (1990) EPJS and GJS scores were analyzed using 1-way ANOVA and Scheffe's test comparing the physicians who left EM with those still in their original jobs, and those who had left their original jobs but who stayed in EM. Mean scores on the 14 "reason for leaving" items were compared with scores from an earlier sample of U.S. physicians using a t-test for independent means. Criteria for statistical significance were set at alpha = 0.05 for all analyses. RESULTS: The response rate for the primary study questions was 99.1%. Of the respondents, 29.4% had left their original jobs, and 10.4% had left EM altogether. The GJS scores for the physicians who left EM were significantly different from those for the physicians who stayed (p = 0.004). The EPJS scores for the physicians who left EM were not significantly different from those for the physicians who stayed (p = 0.56). There was no significant difference in scores between the Canadian and U.S. physicians' reasons for leaving EM (all p-values > 0.05). Shiftwork scored the highest as a reason to leave EM. CONCLUSIONS: A low GJS score is associated with physicians' leaving EM, but not with changing jobs. The EPJS instrument was not associated with either outcome. Canadian and U.S. EPs place similar levels of importance on potential reasons for leaving EM.     

Characterization of a sulfur-rich Arctic spring site and field analog to Europa using hyperspectral data

A unique glacial spring system exists at Borup Fiord pass, in the Canadian High Arctic, emerging from a glacial surface and depositing elemental sulfur, gypsum and calcite across a portion of the glacier. The presence of sulfur springs associated with glacial ice is extremely rare in a terrestrial context, and the resulting deposits may provide a field analog to non-ice materials on the surface of Europa. Spectral characterization of the supraglacial deposits in the visible-near infrared (VIS-NIR) range, 0.4-2.5 µm, was carried out using reflectance spectra collected in situ using a field spectrometer during the 2006 field season. These spectra, while dominated by melting snow, ice, and sulfur, show that some absorption features of the sulfates are shifted in wavelength with respect to library spectra due to the effects of mixing or temperature. Absorption features of calcite are largely absent, potentially due to mineral partitioning effects within the deposits. Investigations into changes in mineralogy within the deposits over the course of the active season using data collected by the Hyperion hyperspectral visible/infrared spectrometer aboard the Earth Observing 1 spacecraft (EO-1) were limited by low signal-to-noise (SNR) ratios in the data, although they indicate that sulfur is remaining stable. This is confirmed by seasonal data on the extent of the deposits, obtained using a classification algorithm running onboard the satellite, which continued to detect the presence of sulfur until snow obscured the site. Ground truth for the observations is provided by mineralogical analyses obtained by X-ray diffraction (XRD) measurements and laboratory reflectance spectra from 0.2-25 µm obtained of samples returned from the site in 2006. We show that while sulfur, the main constituent of the deposits, is well represented in Hyperion data, minor constituents such as calcite and gypsum can be partially or entirely masked in the data. In spite of these effects, autonomous detection methods can be utilized to monitor the generation and extent of the deposits, whose spectral properties show similarities with those of Europa's non-ice materials.     

Carotid artery occlusion due to bacterial paranasal sinusitis

BACKGROUND: Many experts have suggested that blunt splenic trauma in patients older than 55 years should not be managed by observation because of supposed increased fragility of the spleen and decreased physiologic reserve in elderly patients. We sought to determine the outcome of nonoperative management of blunt splenic trauma in patients older than 55 years. METHODS: For the years 1994 through 1996, data for patients with splenic injury older than 55 years from seven trauma centers in a single state were reviewed. RESULTS: Blunt splenic trauma occurred in 41 patients older than 55 years. Eight patients were excluded from further analysis because of death from massive associated injuries within 24 hours of admission. The remaining 33 patients (mean age, 72+/-10 years) were divided into two groups: immediate exploration (10 patients) and observation (23 patients). Observation of blunt splenic injury failed in 4 of 23 patients (17%). No patient deaths were related to the method of management of the splenic injury. CONCLUSIONS: Observation of the elderly patient with blunt splenic trauma has an acceptable failure rate of 17%.     

The spectrum of endocrine dysfunction in active pulmonary tuberculosis

OBJECTIVE: To determine the expected neonatal outcome in a hypothetical obstetric population with various screening and intrapartum management protocols for the prevention of neonatal group B streptococcal infections. METHODS: We used decision analysis to investigate the performance of various antenatal and intrapartum group B streptococcal screening protocols combined with selective or universal intrapartum antibiotic prophylaxis in preventing neonatal early-onset group B streptococcal disease. Population characteristics, screening test performance, and treatment efficacy profiles were abstracted from previous investigations. RESULTS: In the absence of screening or treatment, the estimated neonatal attack rate and mortality rate were 3.6 and 0.60 cases per 1000 neonates, respectively. Universal antenatal screening at 26-28 weeks' gestation and selective intrapartum prophylaxis (treatment of colonized women with risk factors) or nonselective prophylaxis (treatment of all colonized women) had attack rates of 1.64 and 1.08 and mortality rates of 0.21 and 0.18 cases per 1000 neonates, respectively. Rapid intrapartum screening and selective prophylaxis had an estimated attack rate of 1.92-2.58 and a mortality rate of 0.26-0.40 cases per 1000 neonates, with results dependent upon the time required to attain test results. Similarly, rapid intrapartum screening and nonselective prophylaxis had an attack rate of 1.44-2.30 and a mortality rate of 0.24-0.38 cases per 1000 neonates. Empirical prophylaxis of all women delivering prematurely, regardless of culture status, had an attack rate of 2.40 and mortality rate of 0.36 cases per 1000 neonates. CONCLUSIONS: Under ideal circumstances, antenatal group B streptococcal screening at 26-28 weeks' gestation with vaginal-rectal cultures and subsequent intrapartum prophylaxis is associated with lower projected neonatal attack and mortality rates than protocols using rapid intrapartum screening methods. However, in a non-research population, difficulties frequently encountered with antenatal screening procedures may minimize these differences.     

Novel biologically active nonpeptidic inhibitors of myristoylCoA:protein N-myristoyltransferase

A new class of biologically active nonpeptidic inhibitors of Candida albicans NMT has been synthesized starting from the octapeptide ALYASKLS-NH2 (2). The synthetic strategy entailed the preparation of novel protected Ser-Lys mimics 9 and 12 from (S)- or (R)-3-iodotyrosine and then grafting key enzyme recognition elements in a stepwise manner. Like 2, compounds 16, 17, and 18 are competitive Candida NMT inhibitors that bind to the peptide recognition site of the enzyme. Moreover, 16-18 have an affinity comparable to that of 2 even though they are devoid of peptide bonds. In contrast to 2, these nonpeptidic inhibitors exhibit antifungal activity.