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The need for sustainable agricultural systems, which for example enhance soil organic carbon (SOC) content, has increased the interest for management with reduced tillage. In this study we used a Swedish long-term (20 yrs.) systems experiment, including reduced tillage (harrowing 10 cm) and plowing (moldboard plow 0–20 cm) combined with three levels of nitrogen (N) fertilization. With this setup w
We consider a selection of recent experimental results on electroweak W±,Z gauge boson production in pp collisions at BNL RHIC and CERN LHC energies in comparison to prediction of perturbative QCD calculations based on different sets of NLO parton distribution functions including the statistical PDF model known from fits to the DIS data. We show that the current statistical PDF parametrization (fi
We developed a process-oriented model called NutsFor that simulates nutrient cycling of major cations (Ca, Mg, K, Al, NH4, Na) and anions (NO3, SO4, Cl) and the stable isotope tracers for each of the respective elements at the scale of an ecosystem (isotopic fractionation are not simulated). We tested the ability of NutsFor to reproduce major element and stable isotope tracer (26Mg and 44Ca) cycli
A pocket cavity is generated when the Low Pressure Turbine (LPT) is connected to the Outlet Guide Vane (OGV) in the rear part of a gas turbine engine due to the different conjugate diameters. This kind of pocket cavities, due to the high Reynolds number and the specific shapes, are hardly investigated in previous researches. The heat transfer distribution and fluid flow over the pocket cavity have
Three episodes of Paleoproterozoic magmatism with distinctively different nature in the Liaoji belt of the Eastern North China Craton are discussed here: the 2200–2140 Ma Liaoji A-type granites, the 2160–2110 Ma Haicheng mafic sills and the ∼1890 Ma Qingchengzi I-type granites. The Mafeng monzogranitic pluton, representative of the Liaoji A-type granites, gives a SIMS U-Pb zircon age of 2181 ± 6 M
The flow field design of current collectors is a significant issue, which greatly affects the mass transport processes of reactants/products inside fuel cells. Especially for proton exchange membrane (PEM) fuel cells, an appropriate flow field design is very important due to the water balance problem. In this paper, a wavy surface is employed at the cathode flow channel to improve the oxygen mass
This paper documents and evaluates seasonal trends in reproductive performance in the Marsh Tit (Parus palustris) in southern Sweden. Clutch size decreased for nests started later in the season. This pattern held true both for second-year and older females when analyzed separately. Individual females adjusted clutch size in relation to the relative time of season they produced a clutch a particula
In southern Sweden, the starling (Sturnus vulgaris) has a variable mating system with some males mating monogamously and others attracting several females. Mating status affected the reproductive success of females: monogamous and primary females laid larger clutches and fledged more and heavier young than secondary females. This pattern was explained by female competition for male help, with the
In this paper we show that nestling mass hierarchies in the European Starling (Sturnus vulgaris) are due to asynchronous hatching. The parents may, by starting to incubate the day the penultimate egg is laid, or earlier, affect the degree of hatching asynchrony and thereby the nestling weight hierarchy. Intra-clutch variation in egg size had no effect on nestling weight hierarchies, explaining onl
A novel formulation of the theory of parent-offspring conflict is proposed. The basis of this formulation is an application of traditional life-history theory in combination with simple genetic arguments. The advanatage with this approach is conceptual, and the formulation is not in variance with earlier studies in the area. Parent-offspring conflict is, in our forumlation, not seen as a conflict
Reproductive success in relation to egg size was studied in European Starlings (Sturnus vulgaris) by swapping whole clutches between nests at the start of the incubation period. Egg size did not reflect parental quality as no measure of reproductive success was correlated with the foster mothers' mean egg size. There was a significant positive relationship between the mean size of the cross-foster
In polygynous passerines, males of some species provide food for their nestlings, but male incubation seems to be rare. In the European starling both the mating system and the extent to which males help with incubation vary. This enabled the relationship between mating system and male incubation to be investigated. The extent to which males provided care to a particular nest depended on mating sta
Males should invest in mate attraction, mate guarding and paternal care in relation to the marginal fitness value of each of those behaviours. Since time and energy are limited, trade-offs between these activities are expected. This study demonstrates that monogamous male European starlings (Sturnus vulgaris) decrease their paternal effort in response to increased opportunities to attract addition
In altricial birds, growth rates and nestling morphology vary between broods. For natural selection to produce evolutionary change in these variables, there must exist heritable variation. Since nestling traits are not any longer present in parents, traditional offspring-parent regressions cannot estimate heritabilities of these. In this study, a partial cross-fostering experiment was performed, w
Most models explaining polygyny in birds have concentrated on variation in male or territorial quality, ignoring the role of females in maintaining monogamy. Although field observations have suggested that already mated females may maintain monogamy by either behaving aggressively toward prospecting females or by interupting male mate attraction behaviour, no experiments have been done to test if
The extent to which male birds in polygynous species with biparental care assist in nestling feeding often varies considerably between nests of different mating status. Both how much polygynous males assist and how they divide their effort between nests may have a profound effect on the evolution of mating systems. In this study we investigated how males in the facultatively polygynous European st
Intraspecific female aggression during the breeding season can have several different functions: defence of resources, defence against intraspecific brood parasitism and defence of mating status. The intraspecific aggressive behaviour of breeding female starlings, Sturnus vulgaris, was examined by exposing them to a simulated intrusion of a conspecific bird. A caged male or female starling was pla
In many polygynous bird species, males allocate most of their parental effort to their primary females’ broods. There are several hypotheses that may explain this: the relative reproductive value of the brood, the energetic demand of the brood, the genetic quality of the female and the certainty of fatherhood may all be higher for the primary females’ broods. Since these parameters may covary in n
In spite of the fact that hatchling size and energy reserves in birds are affected by egg size, many studies have failed to find an effect of egg size on offspring fitness. One possibility is that this is because they have been performed in areas with high food availability and that effects of egg size on offspring fitness are most apparent in areas of low food availability. To investigate this, e
In the facultatively polygynous European starling (Sturnus vulgaris) males attract from one to four mates. Males gain by mating polygynously because they produce more offspring by doing so. This is true also genetically, since polygynous males on average father the same proportion of offspring as monogamous males. However, the marginal benefit of attracting additional mates is negatively affected
