Connections between deformation-temperature and deformation-entropy constraints and near-constraints in thermoelasticity

Two types of thermomechanical constraint are known to the literature, the first consisting of a relation between the deformation and temperature, the second consisting of a relation between deformation and entropy. The first is known to be unstable in response to small disturbances and the second stable. Insight into these unphysical instabilities is sought by modelling each constraint as the limit of a nearly constrained thermoelastic material. It is found that each deformation-entropy near-constraint is equivalent to a corresponding deformation-temperature near-constraint. But the limit of the deformation-entropy constraint holding exactly is found to correspond to a situation where the limit of the deformation-temperature near-constraint has not been reached. Then this constraint holds only approximately and the need for unphysical instabilities is avoided.     

Hereditary motor and sensory neuropathies. Clinical and molecular genetic aspects

Hereditary motor sensory neuropathies are a heterogeneous group of inherited diseases of the peripheral nerves. In this review the clinical and genetic differences between the sub-groups of this disease will be discussed. Since the discovery of a 1.5 mb duplication on chromosome 17 p11.2-12 in most patients with a hereditary motor sensory neuropathy and a variety of different mutations on chromosomes 1 and X in other patients with a similar disease profile, Dycks' clinical classification needs to be re-evaluated. In this review Dycks' taxonomy of heridihary neuropathies will be compared to a new genetic classification and a relevant diagnostic procedure proposed when a hereditary neuropathy is suspected.     

External-Memory Algorithms for Processing Line Segments in Geographic Information Systems

In the design of algorithms for large-scale applications it is essential to consider the problem of minimizing I/O communication. Geographical information systems (GIS) are good examples of such large-scale applications as they frequently handle huge amounts of spatial data. In this paper we develop efficient external-memory algorithms for a number of important problems involving line segments in the plane, including trapezoid decomposition, batched planar point location, triangulation, red--blue line segment intersection reporting, and general line segment intersection reporting. In GIS systems the first three problems are useful for rendering and modeling, and the latter two are frequently used for overlaying maps and extracting information from them.     

Milk production, health, behavior, and endocrine responses of cows exposed to electrical current during milking

Six cows were exposed during milkings to electrical current to assess its effects on behavior, health, milking performance, and endocrine responses. Three treatments (0, 4, and 8 mA) were applied in a changeover design over three consecutive 1-wk periods. A cow received the same current treatment during 14 consecutive milkings, beginning with the evening milking (d 1) and ending with the morning milking (d 8). Treatments began 5 min before milking and continued until milking unit removal. Treatments consisted of 60 Hz square wave current of 5-s duration applied every 30 s from udder to hooves. Milk accumulation curves provided information about milk yields, milking times, peak milk flow rates, and times of peak milk flow. Residual milk yields also were measured. Milk was analyzed for protein, fat, and somatic cells. Blood samples from 60 min before to 60 min after treatment were collected, and oxytocin, prolactin, and cortisol concentrations were measured. Behavioral responses to current decreased with time. Changes of milking performance and milk composition were not significant. Changes of milking related cortisol responses during 8-mA current stimulation were significant. Oxytocin release was delayed during 8-mA treatments. Current treatments did not affect prolactin.     

Life table study of Aedes aegypti (Diptera: Culicidae) in Puerto Rico fed only human blood versus blood plus sugar

Life table studies were performed in 1996 with Aedes aegypti (L.) during the low (cool/dry) and high (hot/rainy) dengue virus transmission seasons in Puerto Rico. Mated adult females from field-collected pupae were placed individually in cages and divided into 2 treatment groups: one was fed only human blood and the other human blood plus a 10% sucrose solution. Survival and number of eggs laid were recorded daily for each female. During both seasons, age specific survivorship was higher for the blood plus sugar group, groups fed only human blood had higher reproductive outputs (mx), and net replacement rates (Ro) for blood only groups were higher than for those fed blood plus sugar. Intrinsic rates of growth (r) were the same for both treatments during the low (cool/dry) transmission season, but higher for the blood-only treatment during the high (hot/rainy) transmission season. Our results indicate that feeding on only human blood provides an evolutionary advantage to Ae. aegypti females in Puerto Rico. These results are similar to those from an earlier study carried out with Ae. aegypti in Thailand; the advantage of feeding on human blood does not seem to be restricted to a particular geographic region. We also found that the benefits associated with human feeding persist through epidemiologically different times of the year. We conclude that feeding on human blood is reproductively beneficial for Ae. aegypti, which may increase their contact with human hosts, and therefore may influence their vectorial capacity for dengue viruses through frequent feeding on blood.