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Sexual selection is often viewed as a promoter of population divergence, although some forms of sexual selection could rather hamper divergence. In the present study, we investigated whether sexual selection promotes divergence in sexually-selected traits. We studied population variation in sexual selection in relation to colour morph and body size in islet and mainland populations of the Skyros w
Horizontal gene transfer involves the non-sexual interspecific transmission of genetic material. Even if they are initially functional, horizontally transferred genes are expected to deteriorate into non-expressed pseudogenes, unless they become adaptively relevant in the recipient organism. However, little is known about the distributions of natural transgenes within wild species or the adaptive
Soil disturbance is a common phenomenon in semi-natural sandy grasslands, caused by management practices, livestock trampling and erosion. To better understand ecosystem processes when the surface layers of the soil are disturbed, we investigated the effects of disturbance on different functional microbial groups by the use of signature fatty acid analysis. Four levels of disturbance were investig
The structural and magnetic properties of MnSb layers grown on two differently oriented GaAs substrates are reported. The MnSb compounds grow nonhomogenously both on GaAs (111) B and on GaAs (100) substrates. In x-ray diffraction studies the formation of two epitaxial domains is observed depending on the crystallographic orientation of the substrate. The observed diffusion of Ga atoms from the sub
BACKGROUND: Although it is well known that analgesics contribute to suicide, there is little knowledge about how much of the mortality and suicide can be explained by socioeconomic deprivation or by sales of analgesics. METHODS: This ecological study analyses the relationships between the sales (defined daily doses per 1000 inhabitants per day) of dextropropoxyphene, dextropropoxyphene combination
Given the great range of visual systems, tasks and habitats, there is surprisingly little experimental evidence of how visual limitations affect behavioural strategies under natural conditions. Analysing this relationship will require an experimental system that allows for the synchronous measurement of visual cues and visually guided behaviour. The first step in quantifying visual cues from an an
This paper presents a new damage identification technique based on the statistical moments of the energy density function of the vibration responses in the time-scale (or time-frequency) domain. The continuous wavelet transform is first conducted to decompose the vibration responses into discrete energy distributions as a joint function of time and scale. The principal structural response features
We aimed to assess whether prey organisms with limited large-scale dispersal abilities are locally adapted to prevailing predator regimes by studying how chemical cues from predatory fish affected the behavior of Gammarus pulex (Amphipoda) from ponds with and without fish. We also examined, in the laboratory, the F1 generation from each pond by incubating them with or without cues from predatory f
The cytokine transforming growth factor beta-1 (TGFbeta1), was transfected into a TGFbeta1-negative rat colon carcinoma. The growth of isografts of TGFbeta1-expressing tumors was compared to that of vector control transfectants. The TGFbeta1 transfectant grew significantly more slowly after intrahepatic isografting than did vector control and wild-type tumors. The TGFbeta1-transfected tumor tissue
I examine the relationship between reproductive success and marker-based relatedness (MBR; inferred from variation at 21 microsatellite loci) of pair-mates in a semi-isolated population of great reed warblers (Acrocephalus arundinaceus) over a 12 year period. There was a negative relationship between egg-hatching success and MBR, but no association between MBR and three other components of fitness
Variation in ontogenetic development among individuals may be a major contributor to morphological variation within species. Evolution of different growth trajectories might, for example, evolve as a response to varying ecological contexts of individuals living in different environments, or by life-stage or gender differences. The intertidal periwinkle Littorina saxatilis is strongly polymorphic i
BACKGROUND: The plasma level of endothelin-1 is locally increased during cooling but the net vasoconstrictor effect will be dependent on temperature effects on the vascular smooth muscle reactivity in response to the polypeptide. The aim of this study was to investigate the effect of cooling on the vascular smooth muscle response to endothelin-1 in human and rat veins. METHODS: Registration of vas
Forests cover about 56% of the land area in Sweden and forest damage due to strong winds has been a recurring problem. In this paper we analyse recorded storm damage in Swedish forests for the years 1965-2007. During the period 48 individual storm events with a total damage of 164 Mm(3) have been reported with the severe storm on 8 to 9 January 2005, as the worst with 70 Mm(3) damaged forest. For
Migratory birds use compass systems derived from the geomagnetic field, the stars, the sun and polarized light patterns. We tested whether birds use a single underlying reference system for calibration of these compasses and, specifically, whether sunset and sunrise polarized light cues from the region of the sky near the horizon are used to calibrate the magnetic compass. We carried out orientati
Human activity often causes a decline in the local density of plant populations. Below some critical lower density, populations may suffer a progressive decline in reproductive success because of the difficulties associated with finding suitable mates. Therefore, to conserve endangered plant species it is necessary to understand in greater detail how changes in population density affect different
We used radiotelemetry to investigate the time of migratory flight initiation relative to available celestial orientation cues and departure direction of a nocturnal passerine migrant, the reed warbler, Acrocephalus scirpaceus, during autumn migration. The study was carried out at Falsterbo, a coastal site in southwest Sweden. The warblers initiated migration from times well after local sunset and
Reconstruction of movement control properties of the brain could result in many potential advantages for application in robotics. However, a hampering factor so far has been the lack of knowledge of the structure and function of brain circuitry in vivo during movement control. Much more detailed information has recently become available for the area of the cerebellum that controls arm–hand movemen
In the present study the geographical distribution, abundance and composition of Gambierdiscus was described over a 600 km longitudinal scale in the Canary Islands. Samples for cell counts, isolation and identification of Gambierdiscus were obtained from five islands (El Hierro, Tenerife, Gran Canaria, Fuerteventura and Lanzarote). Average densities of Gambierdiscus spp. between 0 and 2200 cells g
An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allow
OBJECTIVES: Outcome assessment in large-vessel vasculitis (LVV) remains challenging and this impairs patient management and the conduct of clinical studies. Previous proposals for outcome tools have not included imaging. This study aimed to develop an imaging score to quantify damage in LVV and to assess the difference between Takayasu (TAK) and giant cell arteritis (GCA).METHODS: Ninety-six patie
