W. H. Grinsted: pioneer of teletraffic engineering

W. H. Grinsted was a pioneer of automatic telephony and was responsible for many important innovations. He also appears to have been the first to obtain an analytical solution to the problem of dimensioning telecommunication systems, i.e. determining the number of trunks required to carry the traffic offered with a specified probability of calls being lost because all trunks are busy. Grinsted was also responsible for introducing simulation methods for solving teletraffic problems that are too complex for straightforward analytical solution     

Physical fitness and heart rate recovery from stress.

Examined relationships between a variety of exercise and fitness-related variables and heart rate recovery from a mental stressor. 108 women (mean age 26.4 yrs) participated in 2 laboratory sessions. In the 1st session, exercise and fitness measures were taken. In the 2nd session, Ss completed health and stress-related questionnaires, and heart rate recovery from a serial subtraction task was measured. Faster heart rate recovery was significantly correlated with several fitness indices including {v}{o}?Max, self-reported fitness level, and level of activity in sports. However, faster heart rate recovery was not associated with improved health or mood, or lower general life stress; benefits in these areas were related to higher levels of fitness and exercise. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New digital automatic gain control for p.c.m. signals

A new design for digital automatic gain control for p.c.m. telephony is presented. This new design is capable of processing 30 speech channels. It avoids putting highest gain where there is no speech. It has manual and automatic facilities.     

Poly(p-phenylene terephthalamide) films formed from extrusion and coagulation of liquid crystalline sulphuric acid solutions: Characterization of orientation and void structure,annealing, and upgrading of film mechanical properties

Poly(p-phenylene terephthalamide) (PPD-T) films have been prepared by continuous extrusion of liquid crystalline 17 percent PPD-T/sulphuric acid solutions through an annular die followed by coagulation, Films extruded without drawdown exhibit some polymer chain orientation in the machine direction. This is increased by uniaxially drawing down films. Films produced with a lubricated conical mandrel sitting between the die and the coagulation bath exhibit an equal biaxial orientation. The uniaxially oriented films exhibit highly anisotropic mechanical properties, while the mandrel-produced film exhibits balanced properties. Heat treatment at 350°C results in significant enhancement of the tensile strength of the mandrel film. Void structures in the films have been investigated by mass density, scanning electron microscopy (SEM), and small-angle X-ray scattering (SAXS). Density measurement indicate a void content decreasing with decreasing film thickness and heat treatment. SEM locates micron-size voids in the thickest films, apparently caused by rapid coagulation. SAXS indicates much smaller void sixes which are roughly prolate ellipsoids (long axis in machine direction) for uniaxial films and oblate ellipsoids (short axis in thickness direction) for the mandrel produced films. Various techniques are used to estimate mean void size.     

Performance of a single glazing assembly exposed to a fire in the centre of an enclosure

The result of 14 experiments in which a single glazing assembly was exposed to fires of increasing severity in the centre of an enclosure are presented. The glazing assembly was exposed to a two zone fire enclosure environment with consistency and repeatability within each set of three experiments conducted at each fire severity level evident from the enclosure gas temperature profiles. The results presented include heat release rates, enclosure and local gas temperature, heat flux distribution, glass surface temperatures, shaded glass temperatures, thermally induced strains, crack bifurcation patterns and loss of integrity of the glazing assembly. Limits regarding the maximum incident heat fluxes required to cause catastrophic failure of the glazing assembly are suggested. Copyright © 2002 John Wiley & Sons, Ltd.     

Electrocardiographic effects of desipramine and 2-hydroxydesipramine in children, adolescents, and adults treated with desipramine

OBJECTIVE: To assess the developmental effects of desipramine (DMI) treatment on the electrocardiogram (ECG), we investigated serum concentrations of DMI ([DMI]), and its major active metabolite 2-hydroxydesipramine ([OHDMI]) and ECG parameters. METHODS: ECGs and [DMI] and [OHDMI] were analyzed from 50 children, 39 adolescents, and 30 adult psychiatric patients receiving DMI. RESULTS: There were modest overall correlations between [DMI], [OHDMI], or [OHDMI+DMI], and the PR and QRS intervals when data from all 119 subjects were pooled. Within the pediatric age groups there were no significant associations between serum drug levels and heart rate or conduction intervals; and in all subjects with ECG abnormalities, there were some findings of higher [DMI], [OHDMI], and [OHDMI+DMI]. CONCLUSIONS: These findings indicate that only modest associations of [DMI] and [OHDMI] with ECG conduction intervals were found, and are not likely to be clinically significant in any of the age groups studied. Compared with adults, children and adolescents do not appear to be at increased risks for ECG changes related to DMI treatment or to circulating concentrations of [DMI] or [OHDMI].     

Odor of the muskox

The behavior of captive male muskoxen was observed closely during their characteristic superiority display, the anatomy of the preputial region was studied in two adults and three calves, and preputial washings and preorbital gland secretion were subjected to gas chromatography and mass spectroscopy. During the superiority display, the prepuce was everted to form a pendulous tube tipped with a fringe of matted hair. Owing to the movement of the animal, the urine that dribbled from the preputial opening was liberally applied to the long guard hairs of the belly. The superiority display was almost exclusively confined to dominant males and apparently accounted for their odor. In the quiescent state, the hair seen around the preputial opening was drawn inside and formed an 8 cm-wide band on the lining of the prepuce. The preputial washings contained large amounts of benzoic acid andp-cresol. The infraorbital gland secretion contained cholesterol, benzaldehyde, and a homologous series of saturated -lactones ranging from 8 to 12 carbons. The latter compounds and the natural secretion smell similar to the human nose.     

马斯京根法流量演进系数的扩展运用

提出按长时段推求的马斯京根法流量演进系数K、x,在数值不变的条件下应用于该河段短时段的流量演算,解决了水利水电工程规划设计中的一些特殊要求和水电站日调节不稳定流演进的近似计算问题.假定河槽为棱柱体,经实测资料检验分析,计算精度较高,能够满足工程规划设计的要求.     

Compatibility between Drugs and Polymer in Nanoparticles Produced by the Miniemulsion-Solvent Evaporation Technique

Encapsulation of poorly soluble drugs in polymer nanoparticles is a common strategy to increase bioavailability of drugs. The miniemulsion-solvent evaporation technique is widely used for encapsulating drugs in polymer nanoparticles because it is a versatile process, allowing many drug–polymer pair combinations. However, above a critical concentration of drug, which depends on the drug and polymer, nanoparticles tend to precipitate. Herein, the importance of drug solubility and miscibility in the polymer phase for selecting the optimal polymer matrix is investigated. Ibuprofen, naproxen methyl ester, and naproxen, as models for poorly soluble drugs, are encapsulated with various loadings in polycaprolactone nanoparticles by the miniemulsion-solvent evaporation method. The miscibility between drug and polymer is estimated by calculating Flory–Huggins interaction parameters (χ) from differential scanning calorimetry measurements and calculating the difference in Hansen solubility parameter of drugs and polymer. Both values can be used for determining the feasibility of the drug encapsulation in polymer nanoparticles.     

Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ~1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.