The Irish cystic fibrosis database

We have found records of 1014 Irish cystic fibrosis patients alive by December 1994, belonging to 883 families. Prevalence in the population is 1/3475 and incidence at birth 1/1461, with a gene frequency of 2.6%. Twenty percent of the patients are aged over 20 years, but at present survival rate falls rapidly after that age. We have identified 85% of the mutations on the CFTR gene in a sample of 29% of the families (506 CF chromosomes). Mutation delta F508 is found in 72% of Irish CF chromosomes, G551D in 6.9%, and R117H in 2%. These are the highest frequencies reported for the latter two mutations world wide. Another seven mutations are found in an additional 4% of CF families. We present new microsatellite haplotype data that could be useful for genetic counselling of CF families bearing some of the 15% of CF mutations still unidentified, and comment on possible uses of our database.     

Chip Formation, Acoustic Emission and Surface White Layers in Hard Machining

In hard machining, sawtooth chip formation is due to initiation of adiabatic shear within the lower region of the primary shear zone. Catastrophic failure within the upper region of the shear zone occurs through either of two different mechanisms and results in the rapid release of elastic strain energy. This periodic release of strain energy is the dominant source of acoustic emission during sawtooth chip formation. In addition to adiabatic shearing in the primary and secondary shear zones, there is evidence to suggest that it occurs in the tertiary shear zone also; namely the surface white layer.     

General entropy criteria for inverse problems, with applications todata compression, pattern classification, and cluster analysis

Minimum distance approaches are considered for the reconstruction of a real function from finitely many linear functional values. An optimal class of distances satisfying an orthogonality condition analogous to that enjoyed by linear projections in Hilbert space is derived. These optimal distances are related to measures of distances between probability distributions recently introduced by C.R. Rao and T.K. Nayak (1985) and possess the geometric properties of cross entropy useful in speech and image compression, pattern classification, and cluster analysis. Several examples from spectrum estimation and image processing are discussed     

Treatment with the oral antidiabetic agent troglitazone improves beta cell responses to glucose in subjects with impaired glucose tolerance

Impaired glucose tolerance (IGT) is associated with defects in both insulin secretion and action and carries a high risk for conversion to non-insulin-dependent diabetes mellitus (NIDDM). Troglitazone, an insulin sensitizing agent, reduces glucose concentrations in subjects with NIDDM and IGT but is not known to affect insulin secretion. We sought to determine the role of beta cell function in mediating improved glucose tolerance. Obese subjects with IGT received 12 wk of either 400 mg daily of troglitazone (n = 14) or placebo (n = 7) in a randomized, double-blind design. Study measures at baseline and after treatment were glucose and insulin responses to a 75-g oral glucose tolerance test, insulin sensitivity index (SI) assessed by a frequently sampled intravenous glucose tolerance test, insulin secretion rates during a graded glucose infusion, and beta cell glucose-sensing ability during an oscillatory glucose infusion. Troglitazone reduced integrated glucose and insulin responses to oral glucose by 10% (P = 0.03) and 39% (P = 0.003), respectively. SI increased from 1.3+/-0.3 to 2.6+/-0.4 x 10(-)5min-1pM-1 (P = 0.005). Average insulin secretion rates adjusted for SI over the glucose interval 5-11 mmol/liter were increased by 52% (P = 0.02), and the ability of the beta cell to entrain to an exogenous oscillatory glucose infusion, as evaluated by analysis of spectral power, was improved by 49% (P = 0.04). No significant changes in these parameters were demonstrated in the placebo group. In addition to increasing insulin sensitivity, we demonstrate that troglitazone improves the reduced beta cell response to glucose characteristic of subjects with IGT. This appears to be an important factor in the observed improvement in glucose tolerance.     

Adaptive Filter Processing in Microwave Remote Heart Monitors

This commmunication describes some current applications tions of adaptive filtering to the processing of microwave Doppler signals for heart rate monitoring. The problem has been approached in the past using signal processing techniques such as peak detection or autocorrelation. These methods either require large amounts of data or tend to be unreliable. This communication utilizes some recent techniques used in speech processing and applies them to heartbeat detection, thus allowing on-line processing of sampled microwave heart signals. The presentation includes a model for the signal, brief discussions of the algorithms evaluated, and qualitative analysis of performance compared to EKG measurements.     

Knowledge formation and learning in the management of projects: A problem solving perspective

In contrast to traditional projects, which are assumed to be fully specified and then executed with little learning anticipated, complex projects cannot be fully specified at the outset and require continuous learning over their life cycles. Nevertheless, the key role of knowledge formation and learning in managing complex projects is under-developed for expanding project capability boundaries to include knowledge uncertainty and indeterminacy.     

Evaluating the potential of small-scale renewable energy options to meet rural livelihoods needs: A GIS- and lifecycle cost-based assessment of Western China's options

The economics and livelihoods impacts of stand-alone, small-scale (less than 2 kW) renewable energy technologies for rural electrification are assessed using a representative sample of 531 rural households in three provinces of Western China. Over 20 small wind, photovoltaic (PV) and wind–PV hybrid configurations were evaluated for their potential to meet local electricity needs. The assessment integrates lifecycle costing and geographic information system (GIS) methods in order to provide a comprehensive resource, economic, technological and livelihoods assessment. The results of the analysis indicate that off-grid renewable energy technologies can provide cost-effective and reliable alternatives to conventional generator sets in addressing rural livelihoods energy requirements. Findings also demonstrate the existence of a sizeable market potential for stand-alone renewable energy systems in Western China. In support of market development for these technologies, policy recommendations are provided.     

Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens

The bioproduction of nanoscale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50?nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles have been investigated by x-ray magnetic circular dichroism and indicate the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimized biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently to the less harmful trivalent form.     

Environmental and genetic influences on prereading skills in Australia, Scandinavia, and the United States.

Individual differences in measures of prereading skills and in questionnaire measures of 4-5-year-old twins' print environments in Australia, Scandinavia, and the United States were explored with a behavioral-genetic design. Modest phenotypic correlations were found between environmental measures and the twins' print knowledge, general verbal ability, and phoneme awareness. Lower print knowledge in Scandinavian twins was related to country differences in preschool print environment. Latent-trait behavioral-genetic analyses indicated very strong shared-environment influences on individual differences in Print Knowledge. Genetic influence was also significant. Several other prereading skills varied in their environmental and genetic influence, including a significant contrast between Phonological Awareness and Print Knowledge. Rapid Naming also revealed very strong genetic influence, as did Verbal Memory. Stronger shared-environment influences were found for Vocabulary and Grammar/Morphology. Genetic and environmental correlations among latent traits for General Verbal Ability, Phonological Awareness, and Print Knowledge were high, but there were also significant independent genetic and environmental contributions to each skill. Practical implications include the need for substantial and sustained instructional support for children hampered by genetic constraints on early literacy development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased epinephrine responses to hypoglycemia during sleep

BACKGROUND: In patients with type I diabetes mellitus, hypoglycemia occurs commonly during sleep and is frequently asymptomatic. This raises the question of whether sleep is associated with reduced counterregulatory-hormone responses to hypoglycemia. METHODS: We studied the counterregulatory-hormone responses to insulin-induced hypoglycemia in eight adolescent patients with type I diabetes and six age-matched normal subjects when they were awake during the day, asleep at night, and awake at night. In each study, the plasma glucose concentration was stabilized for 60 minutes at approximately 100 mg per deciliter (5.6 mmol per liter) and then reduced to 50 mg per deciliter (2.8 mmol per liter) and maintained at that concentration for 40 minutes. Plasma free insulin, epinephrine, norepinephrine, cortisol, and growth hormone were measured frequently during each study. Sleep was monitored by polysomnography. RESULTS: The plasma glucose and free insulin concentrations were similar in both groups during all studies. During the studies when the subjects were asleep, no one was awakened during the hypoglycemic phase, but during the final 30 minutes of the studies when the subjects were awake both the patients with diabetes and the normal subjects had symptoms of hypoglycemia. In the patients with diabetes, plasma epinephrine responses to hypoglycemia were blunted when they were asleep (mean [+/-SE] peak plasma epinephrine concentration, 70+/-14 pg per milliliter [382+/-76 pmol per liter]; P=0.3 for the comparison with base line), as compared with when they were awake during the day or night (238+/-39 pg per milliliter [1299+/-213 pmol per liter] P=0.004 for the comparison with base line, and 296+/-60 pg per milliliter [1616+/-327 pmol per liter], P=0.004, respectively). The patients' plasma norepinephrine responses were also reduced during sleep, whereas their plasma cortisol concentrations did not increase and their plasma growth hormone concentrations increased slightly. The patterns of counterregulatory-hormone responses in the normal subjects were similar. CONCLUSIONS: Sleep impairs counterregulatory-hormone responses to hypoglycemia in patients with diabetes and normal subjects.