Reductions in reproductive performance with age have been predicted to result from a general deterioration of performance, i.e. senescence. Variation among species in the onset and rate of this deterioration depends on the age-independent extrinsic mortality rate. If few individuals reach a specific age, the strength of selection for mechanisms that retard senescence will be reduced. The aim of th

Chelatases catalyze the insertion of a specific metal ion into porphyrins, a key step in the synthesis of metalated tetrapyrroles that are essential for many cellular processes. Despite apparent common structural features among chelatases, no general reaction mechanism accounting for metal ion specificity has been established. We propose that chelatase-induced distortion of the porphyrin substrate

This paper describes the implementation of a simulation benchmark for studying the influence of control strategy implementations on combined nitrogen and phosphorus removal processes in a biological wastewater treatment plant. The presented simulation benchmark plant and its performance criteria are to a large extent based on the already existing nitrogen removal simulation benchmark. The paper il

Neuropeptide Y (NPY), noradrenaline (NA) and adenosine 5'-triphosphate (ATP) are important co-transmitters in the sympathetic nervous system, which has a central role in cardiovascular control. In order to evaluate if hypertension is associated with alterations in vascular responses to sympathetic co-transmitters we studied the effects of intra-arterial infusion of NPY, NA and ATP on forearm blood

The aim of this study was to analyse the impact of neighbourhood on individual social capital (measured as social participation). The study population consisted of 14,390 individuals aged 45-73 that participated in the Malmö diet and cancer study in 1992-1994, residing in 90 neighbourhoods of Malmö, Sweden (population 250,000). A multilevel logistic regression model, with individuals at the first

The nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) is related to the radiation-dependent concentration of polymer formed in polymer gel dosimeters manufactured from monomers in an aqueous gelatin matrix. Changes in T2 with time post-irradiation have been reported in the literature but their nature is not fully understood. We investigated those changes with time after irradiation u

Mucosal pathogens use diverse and highly specific molecular mechanisms to activate mucosal inflammation. It may even be argued that their virulence depends on the inflammatory response that they induce. Some bacteria target epithelial cells and trigger them to produce inflammatory mediators but others cross the mucosa and activate macrophages or dendritic cells. Although systemic release of inflam

One of the major histopathological hallmarks of Alzheimer's disease (AD) is redundant senile plaques mainly composed of beta-amyloid (Abeta) aggregates. Alternative cleavage of the amyloid precursor protein (APP), occurring in both normal and AD subjects, results in the generation and secretion of soluble APP (sAPP) and Abeta. We examined the cerebrospinal fluid (CSF) for alpha- and beta-secretase

We present a theory of very long waves propagating on the surface of water. The waves evolve slowly, both on the scale e (weak nonlinearity), and on the scale, a, of the depth variation. In our model, dispersion does not affect the evolution of the wave even over the large distances that tsunamis may travel. We allow a distribution of vorticity, in addition to variable depth. Our solution is not v

How can we reconcile the conception of language as a conventional-normative semiotic system with a perception/action-based account of its structure and meaning? And why should linguistic meaning - as opposed to linguistic expression - be so closely related to motor activity and its neural underpinnings, as suggested by recent findings? A conceptual framework and evolutionary scenario building on t

During the last half century, a dramatic downscaling of electronics has taken place, a miniaturization that the industry expects to continue for at least a decade. We present efforts to use the self-assembly of one-dimensional semiconductor nanowires(1) in order to bring new, high-performance nanowire devices as an add-on to mainstream Si technology. The nanowire approach offers a coaxial gate-die

This paper concerns voting with logical consequences, which means that anybody voting for an alternative x should vote for the logical consequences of x as well. Similarly, the social choice set is also supposed to be closed under logical consequences. The central result of the paper is that, given a set of fairly natural conditions, the only social choice functions that satisfy social logical clo

The purpose of this study was to investigate the influence of selective denervation of the rat pancreas on hormone secretion and on peripheral insulin sensitivity. Thirteen rats, 7 denervated and 6 sham operated, received an intravenous glucose challenge for 30 min. The basal plasma levels of insulin, glucagon and glucose did not differ between the two groups. An augmented insulin response to gluc

The white-rot fungus Bjerkandera sp. BOL-13 was evaluated regarding decolorization of four textile dyes Reactive blue 21, Reactive black 5, Reactive orange 13 and Reactive yellow 206. Experiments were performed in batch and continuous modes. The total dye concentration in all experiments was 100 mg l(-1). The results of the batch experiments showed that the fungus decolorized all dyes but at diffe

Objectives: To compare personality features of fibromyalgia patients with those of a disease control group with regional pain. Methods: A group of 33 women with fibromyalgia [FMS-group] was compared on the Minnesota Multiphasic Personality Inventory [MMPI] and the Defense Mechanism Technique modified [DMTm] with 31 women [C-group] without this diagnosis who had localized chronic pain in their neck

We consider the problem of minimizing the number of multiplications in computing f(x)=x n , where n is an integer and x is an element of any ring. We present new methods which reduce the average number of multiplications comparing with well-known methods, such as the binary method and the q-ary method. We do not compare our approach with algorithms based on addition chains since our approach is in

BACKGROUND: Despite screening of blood donors, hepatitis C virus (HCV) infection can occur in patients who receive multiple transfusions. OBJECTIVE: To clarify mechanisms of nosocomial transmission of HCV. DESIGN: Epidemiologic and molecular analyses of hepatitis C outbreaks. SETTING: Pediatric oncology ward. PATIENTS: Children with cancer. MEASUREMENTS: Epidemiologic analysis, HCV RNA detection,

The spatial and temporal pattern of land degradation in northeastern Iceland during the Holocene is analysed in relation to climatic fluctuations. Tephrochronology is used to date the infer-red terrestrial changes. and remote sensing and geographical information systems to assess the dynamic relationships between topographic relief. geomorphic processes and soil structure. Changes in vegetation an