Peak expiratory flow rate control chart in asthma care: chart construction and use in asthma care

We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families.     

Comments on “Learning convergence in the cerebellar modelarticulation controller”

The commenter refers to the paper by Wong-Sideris (ibid. vol.3, p.115-21 (1992)) claiming that the original Albus CMAC (or binary CMAC) is capable of learning an arbitrary multivariate lookup table, the linear optimization process is strictly positive definite, and that the basis functions are linearly independent, given sufficient training data. In recent work by Brown et al. (1994), however, it has been proved that the multivariate binary CMAC is unable to learn certain multivariate lookup tables and the number of such orthogonal functions increases exponentially as the generalization parameter is increased. A simple 2D orthogonal function is presented as a counterexample to the original theory. It is also demonstrated that the basis functions are-always linearly dependent, both for the univariate and the multivariate case, and hence the linear optimization process is only positive semi-definite and there always exists an infinite number of possible optimal weight vectors.     

Tributary use and large-scale movements of grass carp in Lake Erie

Infrequent captures of invasive, non-native grass carp (Ctenopharyngodon idella) have occurred in Lake Erie over the last 30+ years, with recent evidence suggesting wild reproduction in the lake’s western basin (WB) is occurring. Information on grass carp movements in the Laurentian Great Lakes is lacking, but an improved understanding of large-scale movements and potential areas of aggregation will help inform control strategies and risk assessment if grass carp spread to other parts of Lake Erie and other Great Lakes. Twenty-three grass carp captured in Lake Erie’s WB were implanted with acoustic transmitters and released. Movements were monitored with acoustic receivers deployed throughout Lake Erie and elsewhere in the Great Lakes. Grass carp dispersed up to 236 km, with approximately 25% of fish dispersing greater than 100 km from their release location. Mean daily movements ranged from <0.01 to 2.49 km/day, with the highest daily averages occurring in the spring and summer. The Sandusky, Detroit, and Maumee Rivers, and Plum Creek were the most heavily used WB tributaries. Seventeen percent of grass carp moved into Lake Erie’s central or eastern basins, although all fish eventually returned to the WB. One fish emigrated from Lake Erie through the Huron-Erie Corridor and into Lake Huron. Based on our results, past assessments may have underestimated the potential for grass carp to spread in the Great Lakes. We recommend focusing grass carp control efforts on Sandusky River and Plum Creek given their high use by tagged fish, and secondarily on Maumee and Detroit Rivers.     

Zirconium-based intermetallics as heterogeneous catalysts for the fischer-tropsch reaction: I. Zr-Ni-Co catalysts

Alloys of the general formula Zr₅₀Ni_xCO_50-x, where 0 ≦x≧ 50, have been prepared and used in the temperature range 300–400°C, in the pressure range 1–9 barg in a microtubular reactor for the reaction of hydrogen with carbon monoxide to give hydrocarbons. The alloys or intermetallic materials were prepared by argon arc melting, powdered by hydrogen decrepitation and characterised by means of optical microscopy (metallography), scanning electron microscopy with surface analysis and magnetic susceptibility measurements. The selectivity towards higher hydrocarbons increased with (i) increase in the total pressure and (ii) decrease in hydrogen content of the feed gases. The kinetics were found to be of the form: where m = 1.0 ± 0.2 and n = 0. The apparent energy of activation (E_a) lay in the range of 80–130 kJ mole^?1 and there appeared to be a compensation effect between E_a and the pre-exponential factor A. The turnover numbers for the reaction exhibited an activity maximum for alloys of composition around Zr₅₀Ni₄₀Co₂₀ and Zr₅₀Ni₃₀Co₂₀. Magnetic susceptibility measurements indicated that alloys changed their nature from moderately paramagnetic to strongly paramagnetic or even ferromagnetic after use and this is attributed to the conversion of zirconium to zirconium oxide during reaction with the attendant production of free 3d-transition metals. Derived catalysts prepared by air treatment of the hydrogen-decrepitated intermetallics behaved almost identically to the latter materials and gave similar magnetic susceptibility values to used hydrided materials.     

Roundup: extractors. Eight manufacturers of extractors provide details about their systems

Choosing an extractor for a specific set of plant conditions can be complicated and costly, if you make the wrong purchasing decision. Extractors come in two types: centrifugal and compression, but there are numerous models of each. Here, eight manufacturers of extractors provide details about their systems.     

Lithotripsy pulse measurement errors due to nonideal hydrophone and amplifier frequency responses

When using miniature ultrasonic hydrophones to probe the focal region of extracorporeal shock wave lithotripsy devices, the frequency response of the measurement hydrophone and any associated amplifier must be broad enough to minimize pulse distortion. To study the potential effects of the bandwidth-limited behavior, a mathematical model was used. Several parameters of a simulated lithotripsy pulse were compared before and after being filtered by hydrophone and amplifier response functions. Errors were computed for the peak positive and negative pressures, risetime, pulse duration, and pulse intensity integral as functions of hydrophone and amplifier bandwidths. Although most of the energy in a shock wave pulse lies at frequencies below a few megahertz, it is found that significant errors can occur unless measurement bandwidths are much wider.