A new analysis of the nearly century-old Lotka-Volterra theory allows us to link species interactions to biodiversity patterns, including: species abundance distributions, estimates of total community size, patterns of community invasibility, and predicted responses to disturbance. Based on a few restrictive assumptions about species interactions, our calculations require only that the community i

C-4 savanna grass species, Digitaria eriantha, Eragrostis lehmanniana and Panicum repens, were grown under optimum growth conditions with the aim of characterizing their above- and below-ground biomass allocation and the response of their gas exchange to changes in light intensity, CO2 concentration and leaf-to-air vapour pressure deficit gradient (D-l). Digitaria eriantha showed the largest above

Ovarian carcinoma is the fourth most common cause of cancer death in women. The cause and pathogenesis of this disease has remained obscure. Galactose, the hydrolyzing product of the milk sugar lactose, has been hypothesized to be toxic to ovarian epithelial cells and consumption of dairy products and lactase persistence has been suggested to be a risk factor for ovarian carcinoma. In adults, down

In mammals, the increase in gene dosage, in the form of polyploidy or involving chromosomal fragments, has deleterious effects [1]. Regulation of appropriate gene product amounts has to be warranted by complex dosage-compensation mechanisms. Lower vertebrates, on the other hand, cope very well with ploidy increase [2 4], implying either effective compensation or a lack of necessity for such mechan

Physicochemical properties of solutions of charged colloids are often dominated by the electrostatic interactions present in such systems. A full determination of these properties constitutes a highly nontrivial many-body problem involving long-range interactions. In electrostatically strongly coupled systems, it is essential to explicitly include both the charged colloids and the small ions in th

The fatty acid amide anandamide produces hypotension and a decrease in systemic vascular resistance in vivo. A drop in blood pressure is also seen with synthetic cannabinoid (CB) receptor agonists. The hypotensive responses to anandamide and synthetic cannabinoids are absent in CB1 receptor gene knockout mice. In isolated arteries and perfused vascular beds, anandamide induces vasodilator response

Aims/hypothesis Peroxisome proliferator activated receptor-gamma coactivator-lp (PGC-1 beta, also known as PPARGCIB) expression is reduced in skeletal muscle from patients with type 2 diabetes mellitus and in elderly subjects. Ala203Pro, a common variant in the PGC-1 beta gene is associated with obesity. The aim of this study was to investigate whether the PGC-1 beta Ala203Pro polymorphism influen

Although chronic obstructive pulmonary disease (COPD) patients frequently report symptoms, it is not known which factors determine the course of symptoms over time and if these differ according to the sex of the patient. The current study investigated predictors for presence, development and remission of COPD symptoms in 816 males and 312 females completing 3-yr-follow-up in the European Respirato

General-purpose computing on graphics processing units (GPGPU) is shown to dramatically increase the speed of Monte Carlo simulations of photon migration. In a standard simulation of time-resolved photon migration in a semi-infinite geometry, the proposed methodology executed on a low-cost graphics processing unit (GPU) is a factor 1000 faster than simulation performed on a single standard process

The use of artificial neural networks (ANNs) in problems related to water resources has received steadily increasing interest over the last decade or so. The related method of the self-organizing map (SOM) is an unsupervised learning method to analyze, cluster, and model various types of large databases. There is, however, still a notable lack of comprehensive literature review for SOM along with

1. In intensively farmed agricultural landscapes, many species are confined to very small uncultivated areas such as field margins. However, it has been suggested that these small habitat elements cannot support viable populations of all the species observed there. Instead, species richness and abundance in these small habitat fragments may, at least partly, be dependent on dispersal from larger s

The communicational and computational demands of neural networks are hard to satisfy in a digital technology. Temporal computing solves this problem by iteration, but leaves a slow network. Spatial computing was no option until the coming of modern FPGA devices. The letter shows how a small feed-forward neural module can be configured on the limited logic blocks between RAM and multiplier macro’s.

Abstract in UndeterminedThe in situ Lu-Hf isotope analysis of zircon by laser ablation has emerged as a high-calibre tool for tackling magmatic and crustal evolution. The strength of the approach lies with the ability to target specific zircon growth domains identified by imaging, and thus to unravel polyphase crystallisation histories. However, due to the volume of material being sampled during a

Background: Weused a sensitive and specific beta-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) assay to determine the relationship between BACE1 activity in cerebrospinal fluid (CSF) and markers of APP metabolism and axonal degeneration in early and late stages of Alzheimer disease (AD). Objective: To assess CSF BACE1 activity in AD. Design: Case-control and longitudinal follow-up

Within the Dutch National Research Programme on Climate Change, the emission of methane from urban areas was considered to be one of the uncertain sources in the national methane budget. Amsterdam was chosen to be a representative urban area for methane emission assessment. An emission inventory was made and concentration fields were calculated using the Danish OML model. Calculated concentration