Surface roughness and height-height correlations dependence on thickness of YBaCuO thin films

For high Tc superconducting multilayer applications, smooth interfaces between the individual layers are required. However, in general, e.g., YBaCuO grows in a 3D screw-dislocation or island nucleation growth mode, introducing a surface roughness. In this contribution we study the surface layer roughness as a function of different deposition techniques as well as deposition parameters. Special attention will be paid to the increase in film roughness with increasing film thickness. For these studies we used scanning probe microscopy. From these experiments, we obtained an island density decreasing with a square root dependence on the film thickness. Furthermore, height-height correlations indicate that the film growth can be described by a ballistic growth process, with very limited effective surface diffusion. The correlation lengths ¿ are on the order of the island size, inferring that the island size forms the mean diffusion barrier. This results in a representation of non-correlated islands, which can be considered as autonomous systems

A major QTL affects temperature sensitive adult lethality and inbreeding depression in life span in Drosophila melanogaster

<p>Abstract</p> <p>Background</p> <p>The study of inbreeding depression has major relevance for many disciplines, including conservation genetics and evolutionary biology. Still, the molecular genetic basis of this phenomenon remains poorly characterised, as knowledge on the mechanistic causes of inbreeding depression and the molecular properties of genes that give rise to or modulate its deleterious effects is lacking. These questions warrant the detailed study of genetic loci giving rise to inbreeding depression. However, the complex and polygenic nature of general inbreeding depression makes this a daunting task. Study of inbreeding effects in specific traits, such as age-specific mortality and life span, provide a good starting point, as a limited set of genes is expected to be involved.</p> <p>Results</p> <p>Here we report on a QTL mapping study on inbreeding related and temperature sensitive lethality in male <it>Drosophila melanogaster</it>. The inbreeding effect was expressed at moderately high temperature, and manifested itself as severe premature mortality in males, but not in females. We used a North Carolina crossing design 3 to estimate average dominance ratio and heritability. We found the genetic basis of the lethal effect to be relatively simple, being due mainly to a single recessive QTL on the left arm of chromosome 2. This locus colocalised with a QTL that conditioned variation in female life span, acting as an overdominant locus for this trait. Male life span was additionally affected by variation at the X-chromosome.</p> <p>Conclusion</p> <p>This demonstrates that analysis of large conditional lethal effects is a viable strategy for delineating genes which are sensitive to inbreeding depression.</p

Designing participation processes for water management and beyond

This article addresses the question of how to design participation processes in water management and other fields. Despite a lot of work on participation, and especially its evaluation, this question has received little attention in the research literature. However, it is important, because previous research has made it clear that participation may yield important benefits for humans and the environment but that these benefits do not occur automatically. One precondition is sound design. The design of participation processes has been addressed in detail in the so-called "craft" literature but more rarely in the scientific literature. This article helps close this gap by systematically analyzing and comparing five design guides to determine whether it is possible to combine them into a more robust guide. The article confirms that possibility and presents a preliminary outline for such a guide. Principles for participatory process orientation are presented, as well as numerous partially iterative steps. The adaptive process is laid out in a way intended to help designers determine the objectives of the participation process and the initial design context, and make preplanning choices that eventually lead to the selection of suitable participation mechanisms. There are also design tools that facilitate this work. We discuss how our findings are largely compatible with previous research on participation, notably the work on criteria for "good" or "effective" participation processes. We also argue that our article advances research on an important remaining question in the scientific literature on participation: What process should be chosen in which context

Hearing disability in patients with Fuchs’ endothelial corneal dystrophy: unrecognized co-pathology?

To investigate a possible association between Fuchs' endothelial corneal dystrophy (FECD) and hearing disability. A cross-sectional observational study was performed at the University Medical Center Utrecht. Cases and controls were patients who were treated by a cornea specialist between 2004 and 2008. FECD patients had either already undergone or were planned for a keratoplasty procedure. All controls were patients treated for cataract without any corneal pathology. Cases and controls were matched by age group and gender. A structured telephone interview combined with a validated self-perceived hearing function test (the Hearing Handicap Inventory for the Elderly, screening version; HHIE-S) was used for data collection. Hearing disability was reported in 33 patients (45.8%) in the FECD-group (n = 72, average age: 73 years) versus 50 patients (34.7%) in the control group (n = 144, average age: 73 years). Hearing disability was significantly associated with FECD after adjustment for age, noise exposure, and diabetes mellitus (odds ratio 1.97 95% confidence interval 1.04-3.75). This case-control study reports a significant association between FECD and hearing disability. The causal relation was not evaluated in this study, though mutations in the SLC4A11 gene could have played an important role. This gene encodes for an ion transporter, which has been found in the cornea and inner ear. With the lack of examination with a pure tone or speech audiometry in this study, further studies need to be performed in order to support the association and should include a complete ENT examination with audiometry and genetic researc

Detecting purging of inbreeding depression by a slow rate of inbreeding for various traits:the impact of environmental and experimental conditions

Inbreeding depression (ID) has since long been recognized as a significant factor in evolutionary biology. It is mainly the consequence of (partially) recessive deleterious mutations maintained by mutation-selection balance in large random mating populations. When population size is reduced, recessive alleles are increasingly found in homozygous condition due to drift and inbreeding and become more prone to selection. Particularly at slow rates of drift and inbreeding, selection will be more effective in purging such alleles, thereby reducing the amount of ID. Here we test assumptions of the efficiency of purging in relation to the inbreeding rate and the experimental conditions for four traits in D. melanogaster. We investigated the magnitude of ID for lines that were inbred to a similar level, F ≈ 0.50, reached either by three generations of full-sib mating (fast inbreeding), or by 12 consecutive generations with a small population size (slow inbreeding). This was done on two different food media. We observed significant ID for egg-to-adult viability and heat shock mortality, but only for egg-to-adult viability a significant part of the expressed inbreeding depression was effectively purged under slow inbreeding. For other traits like developmental time and starvation resistance, however, adaptation to the experimental and environmental conditions during inbreeding might affect the likelihood of purging to occur or being detected. We discuss factors that can affect the efficiency of purging and why empirical evidence for purging may be ambiguous.</p

Consequences of fragmentation for the ability to adapt to novel environments in experimental <i>Drosophila</i> metapopulations

We used experimental populations of Drosophila melanogaster, which had either been subdivided (metapopulations) or kept undivided for 40 generations, to study the consequences of population subdivision for the tolerance and adaptive response after six generations of exposure to novel environmental factors (high temperature, medium with ethanol or salt added) for traits with different genetic architectures. In this setup, we attempted to separate the effects of the loss of fitness due to inbreeding (i.e., the survival upon first exposure to stress) from the loss of adaptive potential due to the lack of genetic variation. To place our experimental results in a more general perspective, we used individual-based simulations combining different options of levels of gene flow, intensity of selection and genetic architecture to derive quantitative hypotheses of the effects of these factors on the adaptive response to stress. We observed that population subdivision resulted in substantial inter-deme variation in tolerance due to redistribution of genetic variation from within demes to among demes. In line with the simulation results, the adaptive response was generally lower in the subdivided than in the undivided populations, particularly so for high temperature. We observed pronounced differences between stress factors that are likely related to the different genetic architectures involved in resistance to these factors. From a conservation genetics viewpoint, our results have two important implications: (i) Long-term fragmentation in combination with restricted gene flow will limit the adaptive potential of individual subpopulations because adaptive variation will become distributed among populations rather than within populations. (ii) The genetic architecture of the trait(s) under selection is of great significance to understand the possible responses to novel stresses that may be expected

Dynamics of genetic rescue in inbred <i>Drosophila melanogaster</i> populations

Genetic rescue has been proposed as a management strategy to improve the fitness of genetically eroded populations by alleviating inbreeding depression. We studied the dynamics of genetic rescue in inbred populations of Drosophila. Using balancer chromosomes, we show that the force of heterosis that accompanies genetic rescue is large and allows even a recessive lethal to increase substantially in frequency in the rescued populations, particularly at stress temperatures. This indicates that deleterious alleles present in the immigrants can increase significantly in frequency in the recipient population when they are in linkage disequilibrium with genes responsible for the heterosis. In a second experiment we rescued eight inbred Drosophila populations with immigrants from two other inbred populations and observe: (i) there is a significant increase in viability both 5 and 10 generations after the rescue event, showing that the increase in fitness is not transient but persists long-term. (ii) The lower the fitness of the recipient population the larger the fitness increase. (iii) The increase in fitness depends significantly on the origin of the rescuers. The immigrants used were fixed for a conditional lethal that was mildly deleterious at 25A degrees C but lethal at 29A degrees C. By comparing fitness at 25A degrees C (the temperature during the rescue experiment) and 29A degrees C, we show that the lethal allele reached significant frequencies in most rescued populations, which upon renewed inbreeding became fixed in part of the inbred lines. In conclusion, in addition to the fitness increase genetic rescue can easily result in a substantial increase in the frequency of mildly deleterious alleles carried by the immigrants. This can endanger the rescued population greatly when it undergoes recurrent inbreeding. However, using a sufficient number of immigrants and to accompany the rescue event with the right demographic measures will overcome this problem. As such, genetic rescue still is a viable option to manage genetically eroded populations

Induction of morphological aberrations by enzyme inhibition in Drosophila melanogaster

Zusatz zum Futter vonDrosophila melanogaster von 5-Fluoro-2-deoxyuridin oder Aminopterin induziert überzählige Skutellar- und Dorsozentralborsten sowie gekerbte Flügel. Diese Modifikationen wurden als Konsequenz von Enzymhemmung interpretiert

Pauli-Lubanski scalar in the Polygon Approach to 2+1-Dimensional Gravity

In this paper we derive an expression for the conserved Pauli-Lubanski scalar in 't Hooft's polygon approach to 2+1-dimensional gravity coupled to point particles. We find that it is represented by an extra spatial shift $\Delta$ in addition to the usual identification rule (being a rotation over the cut). For two particles this invariant is expressed in terms of 't Hooft's phase-space variables and we check its classical limit.Comment: Some errors are corrected and a new introduction and discussion are added. 6 pages Latex, 4 eps-figure