Optimized Fast Walsh–Hadamard Transform on GPUs for non-binary LDPC decoding

The Fourier Transform Sum-Product Algorithm (FT-SPA) used in non-binary Low-Density Parity-Check (LDPC) decoding makes extensive use of the Walsh–Hadamard Transform (WHT). We have developed a massively parallel Fast Walsh–Hadamard Transform (FWHT) which exploits the Graphics Processing Unit (GPU) pipeline and memory hierarchy, thereby minimizing the level of memory bank conflicts and maximizing the number of returned instructions per clock cycle for different generations of graphics processors, with considerable speedup gains in FT-SPA based non-binary LDPC decoding.     

The incidence of giant cell arteritis in Olmsted County, Minnesota: apparent fluctuations in a cyclic pattern

OBJECTIVE: To investigate trends in the incidence of giant cell arteritis over a 42-year period in Olmsted County, Minnesota. DESIGN: Population-based incidence study. SETTING: Olmsted County, Minnesota. METHODS: All incidence cases of giant cell arteritis first diagnosed between 1950 and 1991 were identified using the unified record system at Mayo Clinic. Age- and sex-specific incidence rates were calculated using the number of incidence cases as the numerator and population estimates as the denominator. Overall rates were age- and sex-adjusted to the 1980 United States white population. The annual incidence rates were graphically illustrated using a 3-year centered moving average. RESULTS: Between 1950 and 1991, 125 Olmsted County residents (103 women and 22 men) were diagnosed with giant cell arteritis. The age- and sex-adjusted incidence per 100,000 persons 50 years of age or older was 17.8 (95% CI, 14.7 to 21.0); incidence was significantly higher in women (24.2 [CI, 19.5 to 28.9]) than in men (8.2 [CI, 4.8 to 11.6]). Age-specific incidence rates increased with age (P < 0.0001). The annual incidence rates increased significantly over the study period (P = 0.002) and appear to have clustered in five peak periods, which occurred about every 7 years. A significant calendar-time effect was identified; it predicted an increase in incidence of 2.6% (CI, 0.9% to 4.3%) every 5 years. CONCLUSIONS: Our observation of a regular cyclic pattern in incidence rates over time supports the hypothesis of an infectious cause for giant cell arteritis. Similar studies in other populations are needed to confirm our findings.     

Chronic non-B, non-C hepatitis among blood donors assessed with HCV third generation tests and polymerase chain reaction

Forty five blood donors with increased serum aminotransferases levels had liver histologic assessment and were tested for antibodies to hepatitis C virus (anti-HCV) with second and third generation ELISAs and RIBAs, and for HCV RNA with polymerase chain reaction (PCR) in serum and liver tissue. Twenty-nine of these 45 donors (65%) had steatosis without chronic hepatitis. Sixteen (35%) had chronic hepatitis. Twelve had evidence of HCV infection. Four had no evidence of HCV infection demonstrable by ELISA, RIBA or PCR. These four patients had no known cause of chronic hepatitis and no risk factor for parenterally acquired viral infection was found in them. This observation supports the hypothesis that a non-B, non-C virus might be implicated in chronic hepatitis. However, this hypothesis remains to be demonstrated.     

Speech development in preschool children. II. Sex differences in articulation and tongue motility

Transfatty acids are geometrical isomers of the naturally occurring cis-fatty acids, and their molecular configuration is more like that of the corresponding saturated fatty acid. In view of the large amounts of trans-acids in commercially prepared margarines, metabolic studies with trans-acids have received a great deal of attention. Although there are differences in the absorption and digestion of trans-acids and although considerable amounts are deposited in various tissues, no definite signs of toxicity have been observed. An important finding is the increased requirement for essential fatty acids in animals fed high levels of trans-acids. In recent work carried out in Kummerow's laboratory, aortic lesions were found in swine fed large amounts of trans-acids. Evaluation of the data suggests that factors other than trans-acids, per se, may have been responsible for the occurrence of the lesions. As yet, there does not seem to be any valid reason why trans-acids should be excluded from the diet as long as their intake is associated with a high enough level of essential fatty acids in the diet.     

Investigation of the elementary reactions in the synthesis of poly(hydroxethers) in dipolar,aprotic solvents

The effect of the hydroxyl groups of various phenols on the course of the reaction of their alkali metal salts with epichlorohydrin in dipolar, aprotic solvents has been studied. It was found that the presence of phenols in the system leads to the formation of a complex salt of the type (ArO … H … OAr)^?Mt⁺, and to a considerable decrease in the reaction rate. The mechanism of the reaction of chlorohydrin ethers of phenols with alkali metal phenolates was also studied. The effect of various factors on the course of the reaction of glycidyl ethers with phenols was determined by kinetic measurements.     

Measurement of spermatozoal motility over prolonged periods of time using image analysis

This paper presents a new method for the quantitative analysis of the movement characteristics of spermatozoa. The method is based on (i) measuring the displacement of a spermatozoon observed using a microscope and (ii) automatically compensating for the displacement of the spermatozoon in order to keep it in the center of the microscopic field. The displacement of the spermatozoon is measured by on-line processing of digitized images of the microscopic field, acquired by an image analysis system. The motility characteristics of the same spermatozoon can be evaluated over prolonged periods of time (typically 10 min). The movement characteristics of 19 spermatozoa from five fertile donors were studied. At constant temperature, intradonor variations of the motility parameters were found. No statistically significant differences were found in the mean values of the motility characteristics for three of four donors. At increasing temperature, the mean curvilinear velocity, averaged on the 19 spermatozoa from the five donors, regularly increased between 23 and 30 degrees C and remained constant up to 38 degrees C.     

Prediction of attenuation due to rain: Characteristics of the 0°C isotherm in temperate and tropical climates

A detailed investigation of the vertical structure of rain and of the characteristics of the 0°C isotherm height in both rainy and non-rainy conditions has been carried out in connection with the prediction of rain attenuation on Earth-satellite links. Radiosonde data have been analysed for eight and nine locations in the southern and northern hemispheres, respectively. The temporal, latitudinal variations and the relationship between the 0°C isotherm height and ground meteorological parameters such as rainfall, temperature and relative humidity, are reported. The equivalent rain height measured along the Earth-satellite link is compared with the heights obtained from meteorological data.     

Comparison between the dynamics of lipid/gramicidin A systems in the lamellar and hexagonal phases: a solid-state 13C NMR study

Adolescence is a developmental period marked by multiple challenges and demands which create a heightened vulnerability to the development of emotional disorders. Primary care physicians are in an ideal position to intervene in the early stages and prevent the tragic consequences which can occur with an untreated mental health disorder. This article reviews the assessment and treatment of adolescent mental health in the primary care medical setting. Knowledge of these disorders and their manifestations in the primary care environment will enable clinicians to provide higher quality medical care and will reduce the potential for continual life disruptions into the adult years.     

Complete switching in a three-terminal Sagnac switch

A three-terminal all-optical fiber switch based on a fiber Sagnac interferometer is described. The use of polarization components allows the construction of a switch in which the control beam and signal beam are isolated (i.e. the device is three terminal) and which is cascadable (the device output can drive its inputs). The interaction length need not be limited by the walkoff length in the fiber, as cross-splices can be made in the birefringent fiber to permit multiple passes. Contrast ratios as high as 40:1 have been demonstrated in a switch driven by an amplified laser diode.<>