Stochastic modeling of soil salinity

A minimalist stochastic model of primary soil salinity is proposed, in which the rate of soil salinization is determined by the balance between dry and wet salt deposition and the intermittent leaching events caused by rainfall events. The long term probability density functions of salt mass and concentration are found by reducing the coupled soil moisture and salt mass balance equation to a single stochastic differential equation driven by multiplicative Poisson noise. The novel analytical solutions provide insight on the interplay of the main soil, plant and climate parameters responsible for long-term soil salinization. In particular, they show the existence of two distinct regimes, one where the mean salt mass remains nearly constant (or decreases) with increasing rainfall frequency, and another where mean salt content increases markedly with increasing rainfall frequency. As a result, relatively small reductions of rainfall in drier climates may entail dramatic shifts in long-term soil salinization trends, with significant consequences e.g. for climate change impacts on rain-fed agricultur

Morris Water Maze Learning in Two Rat Strains Increases the Expression of the Polysialylated Form of the Neural Cell Adhesion Molecule in the Dentate Gyrus But Has No Effect on Hippocampal Neurogenesis

In the current study, the authors investigated whether Morris water maze learning induces alterations in hippocampal neurogenesis or neural cell adhesion molecule (NCAM) polysialylation in the dentate gyrus. Two frequently used rat strains, Wistar and Sprague–Dawley, were trained in the spatial or the nonspatial version of the water maze. Both training paradigms did not have an effect on survival of newly formed cells that were labeled 7–9 days prior to the training or on progenitor proliferation in the subgranular zone. However, the granule cell layer of the spatially trained rats contained significantly more positive cells of the polysialylated form of the NCAM. These data demonstrate that Morris water maze learning causes plastic change in the dentate gyrus without affecting hippocampal neurogenesis.

Discontinuities without discontinuity: The Weakly-enforced Slip Method

Tectonic faults are commonly modelled as Volterra or Somigliana dislocations in an elastic medium. Various solution methods exist for this problem. However, the methods used in practice are often limiting, motivated by reasons of computational efficiency rather than geophysical accuracy. A typical geophysical application involves inverse problems for which many different fault configurations need to be examined, each adding to the computational load. In practice, this precludes conventional finite-element methods, which suffer a large computational overhead on account of geometric changes. This paper presents a new non-conforming finite-element method based on weak imposition of the displacement discontinuity. The weak imposition of the discontinuity enables the application of approximation spaces that are independent of the dislocation geometry, thus enabling optimal reuse of computational components. Such reuse of computational components renders finite-element modeling a viable option for inverse problems in geophysical applications. A detailed analysis of the approximation properties of the new formulation is provided. The analysis is supported by numerical experiments in 2D and 3D.Comment: Submitted for publication in CMAM

Pathogenic bacteria and indicator organisms for anti-microbial resistance in pork meat at retail level in The Netherlands.

Slaughter pigs and pork carcasses are often contaminated with pathogenic bacteria. Consequently raw meat on sale in retail stores may also contain these bacteria. In The Netherlands the calculated contribution by pigs to the relative occurrence of human salmonellosis in the period 1994-1998 was 25.2 % (van Pelt, 2001). Survey and monitoring data on the contamination of raw products with pathogens like Salmonella, Campylobacter, Listeria monocytogenes and Escherichia coli O157 are essential for making risk estimates, and the results of surveys carried out in 1990/2000 and 2002 are presented here. In 2002 also a surveillance of anti-microbial resistance among indicator bacteria (Escherichia coli, Enterococcus faecium/faecalis) isolated from pork meat was started. The results show that pork meat was contaminated with Salmonella in levels between 6.2 - 10.5 %, S. Typhimurium being the predominant serotype, and to a lesser extent with Campylobacter, Listeria and E. coli O157

A High-Efficiency 4x45W Car Audio Power Amplifier using Load Current Sharing

A 4x45W (EIAJ) monolithic car audio power amplifier is presented that achieves a power dissipation decrease of nearly 2x over standard class AB operation by sharing load currents between loudspeakers. Output signals are conditioned using a common-mode control loop to allow switch placement between loads with minimal THD increase. A prototype is realized in a SOI bipolar-CMOS-DMOS process with 0.5μm feature size. Die area is 7.5x4.6mm2. THD+N @(1kHz,10W) is 0.05%

Diversity of Child and Family Characteristics of Children with Hearing Loss in Family-Centered Early Intervention in The Netherlands

Background: Family-centered early intervention (FCEI) for children with hearing loss (HL) supports caregivers to promote their children’s language development. To provide FCEI services that are relevant and accessible to meet diverse needs, insight into the characteristics of children with HL is important. In the current study, various characteristics of children with HL and intervention-related factors are examined in relation to spoken language outcomes. Methods: Child and family characteristics, language outcomes and data on intervention were extracted from FCEI records for 83 children. Family involvement ratings were obtained from EI providers. Relations between characteristics, intervention, family involvement and language outcomes were analyzed and predictors for children’s language outcomes were investigated. Results: The characteristics of children with HL in FCEI are very diverse. Family involvement and the occurrence of additional disabilities were predictive for children’s receptive and expressive language abilities; the start of FCEI was not. Maternal education was predictive for expressive language outcomes only. Conclusions: The current study showed the diversity in characteristics of children with HL and their families in the degree of HL, etiology, cultural background, home language, family involvement and additional disabilities. We conclude that ’one size does not fit all’, and FCEI programs should acknowledge the unique strengths and challenges of every individual family