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The effect of pollen competition on maintenance of variation in fertilisation ability

Pollen competition in the pistil does not only give flowering plants the possibility to reduce inbreeding but also provides an opportunity for selection of pollen traits that increase male reproductive success. An objection to the existence of selection on pollen competitive ability is that individual variation should quickly vanish if selection is strong. A balance between selection for local ada

From arctic lemmings to adaptive dynamics: Charles Elton's legacy in population ecology

We shall examine the impact of Charles S. Eltons 1924 article on periodic fluctuations in animal populations on the development of modern population ecology. We argue that his impact has been substantial and that during the past 75 years of research on multi-annual periodic fluctuations in numbers of voles, lemmings, hares, lynx and game animals he has contributed much to the contemporary understa

Complement C3 and C4 in plasma and incidence of myocardial infarction and stroke: a population-based cohort study

Background Complement factor C3 and C4 have been associated with atherosclerosis and cardiovascular risk factors. This study explored whether plasma levels of C3 and C4 are risk factors for the incidence of cardiovascular disease (CVD). Design A population-based prospective study of 5850 initially healthy men, 28-61 years old at baseline. Methods Plasma levels of C3 and C4 were analysed at the bas

Examining the utility of categorical models and alleviating artifacts in phylogenetic reconstruction of the Squamata (Reptilia).

Reconstruction artifacts are a serious hindrance to the elucidation of phylogenetic relationships and a number of methods have been devised to alleviate them. Previous studies have demonstrated a striking disparity in the evolutionary rates of the mitochondrial (mt) genomes of squamate reptiles (lizards, worm lizards and snakes) and the reconstruction artifacts that may arise from this. Here, to e

Late Ordovician (Hirnantian) depositional pattern and sea-level change in shallow marine to shoreface cycles in central Sweden

The Upper Ordovician Kyrkas Quartzite Formation at the Nifsasen Quarry (Jamtland, Sweden) exhibits c. 90 m of siliciclastic sedimentary rocks deposited on a shallow shelf at the cratonattached part of tile Caledonian foreland basin. Five lithologies are distinguished, including claystone, mudstone, siltstone, subarkose and sublitharenite. Based on these five lithologies, sedimentary structures and

Suppressed kindling epileptogenesis in mice with ectopic overexpression of galanin

The neuropeptide galanin has been shown to suppress epileptic seizures. In cortical and hippocampal areas, galanin is normally mainly expressed in noradrenergic afferents. We have generated a mouse overexpressing galanin in neurons under the platelet-derived growth factor B promoter. RIA and HPLC analysis revealed up to 8-fold higher levels of galanin in transgenic as compared with wild-type mice.

Core localization and sigma( *) delocalization in the O 1s core-excited sulfur dioxide molecule.

Electron-ion-ion coincidence measurements of sulfur dioxide at discrete resonances near the O 1s ionization edge are reported. The spectra are analyzed using a model based upon molecular symmetry and on the geometry of the molecule. We find clear evidence for molecular alignment that can be ascribed to symmetry properties of the ground and core-excited states. Configuration interaction (CI) calcul

Reappraisal of the regulation of lactococcal L-lactate dehydrogenase

Lactococcal lactate dehydrogenases (LDHs) are coregulated at the substrate level by at least two mechanisms: the fructose- 1,6-biphosphate/phosphate ratio and the NADH/NAD ratio. Among the Lactococcus lactis species, there are strains that are predominantly regulated by the first mechanism (e.g., strain 65.1) or by the second mechanism (e.g., strain NCDO 2118). A more complete model of the kinetic

The differentiation potential of precursor cells from the mouse lateral ganglionic eminence is restricted by in vitro expansion.

We have investigated whether the differentiation potential of attached cultures derived from the mouse lateral ganglionic eminence (LGE) is influenced by in vitro expansion. Primary neuronal cultures derived from the LGE give rise to neurons expressing the striatal projection neuron markers Islet1 (ISL1) and dopamine and cAMP-regulated phosphoprotein of 32 kilodaltons (DARPP-32) as well as the olf

A direct digital RF amplitude modulator

This paper describes a direct digital RF amplitude modulator, which uses a 10-bit linear interpolation current steering digital to analog converter (DAC) and a Gilbert cell mixer to generate an RF amplitude modulated signal directly. The linear interpolation increases the attenuation of the DAC's image components. The low pass filter (LPF) is eliminated, and the RF transmitter structure can be sim

Two-year follow-up of Helicobacter pylori infection in C57BL/6 and Balb/cA mice.

Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. We previously found high-grade lymphoma after 13 months' H. pylori infection in C57BL/6 mice. In this study we followed H. pylori infection by three different isolates in C57BL/6 and Balb/cA mice for 23 months. Six-week-old C57BL/6 and Balb/cA mice were infected with

Effects of anoxia and sulfide on concentrations of total and methyl mercury in sediment and water in two Hg-polluted lakes

Between May and December 1996, monthly samples of surface sediment (0-1 cm), settling matter, and water were taken at a shallow site and a deep site in each of two consecutive Hg-polluted riverine lakes. In the upper lake, the sediment was polluted also with cellulose fiber. Both hypolimnia turned anoxic, but sulfide was detected only in the upper lake. When sulfide appeared, hypolimnetic methyl m

CD44-stimulated human B cells express transcripts specifically involved in immunomodulation and inflammation as analyzed by DNA microarrays

A number of studies have implicated a role for the cell surface glycoprotein CD44 in several biologic events, such as lymphopoiesis, homing, lymphocyte activation, and apoptosis. We have earlier reported that signaling via CD44 on naive B cells in addition to B-cell receptor (BCR) and CD40 engagement generated a germinal center-like phenotype. To further characterize the global role of CD44 in B d

Effect of methyldopa and isradipine on fetal heart rate pattern assessed by computerized cardiotocography in human pregnancy

OBJECTIVE: The effects of two antihypertensive drugs, methyldopa and isradipine, on fetal heart rate pattern were analyzed by computerized cardiotocography. STUDY DESIGN: The first part of the study was a prospective, randomized, controlled trial of 19 women with preeclampsia in the third trimester given 2.5 mg of oral slow-release isradipine twice a day or 250 mg of methyldopa three times a day.

The Central Role of Bcl-3 in Atopic Dermatitis

Cytokines and hormones are essential mediators in the regulation of antimicrobial peptide and protein (AMP) levels during host defense responses. In this issue, Buchau et al. identify and characterize B-cell leukemia-3 as an important modulator of AMP expression during the innate immune response in keratinocytes as well as in the chronic inflammatory skin disorder atopic dermatitis.

Cloud system resolving model study of the roles of deep convection for photo-chemistry in the TOGA COARE/CEPEX region

A cloud system resolving model including photo-chemistry (CSRMC) has been developed based on a prototype version of the Weather Research and Forecasting (WRF) model and is used to study influences of deep convection on chemistry in the TOGA COARE/CEPEX region. Lateral boundary conditions for trace gases are prescribed from global chemistry-transport simulations, and the vertical advection of trace

Psychosocial work conditions, social participation and social capital: A causal pathway investigated in a longitudinal study.

Social capital is often claimed to be promoted by stable social structures such as low migration rates between neighbourhoods and social networks that remain stable over time. However, stable social structures may also inhibit the formation of social capital in the form of social networks and social participation. One example is psychosocial conditions at work, which may be determined by character

Procedure for simulating divergent-light halos

Divergent-light halos are halos produced by light from nearby light sources, like street lamps being scattered by small crystals of ice floating in the air. The use of "brute-force" Monte Carlo methods to simulate such halos is extremely inefficient, as most scattered rays will not hit the eye of the observer. I present a new procedure for Monte Carlo simulations of divergent-light halos. This pro