Finite difference time domain modeling of phase grating diffusion

In this paper, a method for modeling diffusion caused by non-smooth boundary surfaces in simulations of room acoustics using finite difference time domain (FDTD) technique is investigated. The proposed approach adopts the well-known theory of phase grating diffusers to efficiently model sound scattering from rough surfaces. The variation of diffuser well-depths is attained by nesting allpass filters within the reflection filters from which the digital impedance filters used in the boundary implementation are obtained. The presented technique is appropriate for modeling diffusion at high frequencies caused by small surface roughness and generally diffusers that have narrow wells and infinitely thin separators. The diffusion coefficient was measured with numerical experiments for a range of fractional Brownian diffusers.

Modal Representation of the Resonant Body within a Finite Difference Framework for Simulation of String Instruments

This paper investigates numerical simulation of a string coupled
transversely to a resonant body. Starting from a complete nite
difference formulation, a second model is derived in which the
body is represented in modal form. The main advantage of this hybrid form is that the body model is scalable, i.e. the computational
complexity can be adjusted to the available processing power. Numerical results are calculated and discussed for simplied models
in the form of string-string coupling and string-plate coupling.

The ontogenesis of lateralized behavior in the domestic cat, Felis silvestris catus

For the first time, the development of paw preferences in the domestic cat, Felis silvestris catus, is explored. Twelve cats were tested at ages 12 weeks, 6 months, and 1 year on a challenge requiring them to use one of their paws to retrieve food. To control for repeated testing of the same cats at different ages, the subjects' paw preferences were compared with those of cats tested just once, at 6 months (n = 11) or 1 year (n = 14) of age. Analysis revealed a significant effect of age on the distribution of cats' paw preferences. Cats were significantly more likely to be ambilateral than paw preferent at 12 weeks and at 6 months but more likely to display a lateral bias in paw use at 1 year. There was a significant positive correlation between cats' paw preferences at 6 months and at 1 year. Lateralized behavior was strongly sex related. Females had a greater preference for using their right paw; males were significantly more inclined to adopt their left. Analysis revealed no significant difference in the direction or strength of paw preferences of cats tested longitudinally or cross-sectionally at 6 months or 1 year of age. Findings indicate that cats develop paw preferences by 1 year and hint at a relative stability in preferred paw use over time. The strong sex effect observed strengthens the case for the influence of a biological mechanism in the emergence of motor asymmetry in cats.

Evaluation of Pt and Re oxidation state in a pressurized reactor: difference in reduction between gas and liquid phase

Determination of metal oxidation state under relevant working conditions is crucial to understand catalytic behaviour. The reduction behaviour of Pt and Re was evaluated simultaneously as a function of support and solvent in a pressurized reactor (autoclave). The bimetallic catalysts are used in selective hydrogenation of carboxylic acids and amides. Gas phase reduction reduced the metals more efficiently, in particular Pt.

Diabetic retinopathy: quantitative variation in capillary basement membrane thickening in arterial or venous environments

Diabetes mellitus was induced in male beagles by a single injection of an alloxan and streptozotocin cocktail and fasting blood sugar levels maintained between 15 and 20 mmol/l. Five years after induction of diabetes, three diabetic animals were sacrificed, together with sex and age-matched controls, and the retinas fixed for either transmission electron microscopy (TEM) or trypsin digestion. In TEM specimens, capillaries in close proximity to the major vessels were designated as either AE (arterial environment) or VE (venous environment) and the thickness of their basement membranes (BMs) measured using an image analyser based two dimensional morphometric analysis system. Results show that the BMs of retinal capillaries from the diabetic dogs were significantly thicker than those from control dogs. Furthermore, within the diabetic group the AE capillaries had thicker BMs than VE capillaries (p less than or equal to 0.05). The controls, however, showed no significant difference in BM thickness between AE and VE capillaries. Although many of the capillaries designated as AE or VE would actually have been derived from the opposite side of the circulation, with respect to BM thickness, they conformed to values of their specific group. The conclusion is that diabetic capillaries are more vulnerable to BM thickening in an arterial environment than in a venous environment.

Plays of Difference

Review-essay

Why is housing tenure associated with a lower risk of admission to a nursing or residential home? Wealth, health and the incentive to keep 'my home'

Background Previous research has shown that home ownership is associated with a reduced risk of admission to institutional care. The extent to which this reflects associations between wealth and health, between wealth and ability to buy in care or increased motivation to avoid admission related to policies on charging is unclear. Taking account of the value of the home, as well as housing tenure, may provide some clarification as to the relative importance of these factors.
Aims To analyse the probability of admission to residential and nursing home care according to housing tenure and house value.
Methods Cox regression was used to examine the association between home ownership, house value and risk of care home admissions over 6 years of follow-up among a cohort of 51 619 people aged 65 years or older drawn from the Northern Ireland Longitudinal Study, a representative sample of approximate to 28% of the population of Northern Ireland.
Results 4% of the cohort (2138) was admitted during follow-up. Homeowners were less likely than those who rented to be admitted to care homes (HR 0.77, 95% CI 0.70 to 0.85, after adjusting for age, sex, health, living arrangement and urban/rural differences). There was a strong association between house value/tenure and health with those in the highest valued houses having the lowest odds of less than good health or limiting long-term illness. However, there was no difference in probability of admission according to house value; HRs of 0.78 (95% CI 0.67 to 0.90) and 0.81 (95% CI 0.70 to 0.95), respectively, for the lowest and highest value houses compared with renters.
Conclusions The requirement for people in the UK with capital resources to contribute to their care is a significant disincentive to institutional admission. This may place an additional burden on carers.