Separation and identification of dominant mechanisms in double photoionization

Double photoionization by a single photon is often discussed in terms of two contributing mechanisms, {\it knock-out} (two-step-one) and {\it shake-off} with the latter being a pure quantum effect. It is shown that a quasi-classical description of knock-out and a simple quantum calculation of shake-off provides a clear separation of the mechanisms and facilitates their calculation considerably. The relevance of each mechanism at different photon energies is quantified for helium. Photoionization ratios, integral and singly differential cross sections obtained by us are in excellent agreement with benchmark experimental data and recent theoretical results.Comment: 4 pages, 5 figure

Semiclassical threshold law when the Wannier exponent diverges

Using semiclassical methods we investigate the threshold behavior for three-particle breakup of a system with one particle of charge Z and two other particles of charge -q. For the particular case where the ratio of the charges of the third particle to the wing particles is Z/g = 1/4, the Wannier exponent for breakup diverges and the threshold law changes from a power law to an exponential law of the form exp(-lambda/root E). The threshold behavior is tested above the region of divergence and it is found that for Z/q < 0.3 a power law does not hold. Ionizing trajectories show that the dynamics within the near zone can become crucial to the energy dependence of the cross section. Cases are found to arise where more than one trajectory contributes to the same final state giving rise to semiclassical interference effects

Nutritional Deficiencies and Phospholipid Metabolism

Phospholipids are important components of the cell membranes of all living species. They contribute to the physicochemical properties of the membrane and thus influence the conformation and function of membrane-bound proteins, such as receptors, ion channels, and transporters and also influence cell function by serving as precursors for prostaglandins and other signaling molecules and modulating gene expression through the transcription activation. The components of the diet are determinant for cell functionality. In this review, the effects of macro and micronutrients deficiency on the quality, quantity and metabolism of different phospholipids and their distribution in cells of different organs is presented. Alterations in the amount of both saturated and polyunsaturated fatty acids, vitamins A, E and folate, and other micronutrients, such as zinc and magnesium, are discussed. In all cases we observe alterations in the pattern of phospholipids, the more affected ones being phosphatidylcholine, phosphatidylethanolamine and sphingomyelin. The deficiency of certain nutrients, such as essential fatty acids, fat-soluble vitamins and some metals may contribute to a variety of diseases that can be irreversible even after replacement with normal amount of the nutrients. Usually, the sequelae are more important when the deficiency is present at an early age

The effect of public participation in development of infrastructure investments in the procedure of the environmental impact assessment

Celem artykułu jest przedstawienie wpływu udziału społeczeństwa w procedurze oceny oddziaływania na środowisko na rozwój inwestycji infrastrukturalnych oraz wskazanie zalet i wad tego udziału.Economic development is a long-term process, and faces the idea of sustainable development. Development of the infrastructure investments is one of the most important elements which determinate economic growth. The environmental impact assessment (EIA) gives the citizens opportunity of implementation of their sustainable solutions in the wider process of planning infrastructure investments. One of the basic part of the decision process is the environmental impact assessment which lead to the first „investment decision” ie.: the decisions on the environmental conditions. The environmental impact assessment for a project means the procedure of working out the best solutions for the proposed project, including in particular: the verification of the environmental impact report for the project, the acquisition of the opinions and approvals required by the Act of 3 October 2008 on the Provision of Information on the Environment and its Protection, Public Participation in Environmental Protection and Environmental Impact Assessments, ensuring the possibility of public participation in the procedure. This article is based on wide data bases of administration procedures and outlines the procedure for public participation in environmental impact assessment to emphasize its impact positive and negative on the development of infrastructure investments

Dem Regen folgen. Die nomadische Architektur der Afar: Tradition und Herausforderungen

Abweichender Titel nach Übersetzung der Verfasserin/des VerfassersDer Schwerpunkt dieser Arbeit liegt bei einer anthropologischen und architektonischen Aufnahme des Lebensstiles der Afar- Hirten in Äthiopien, aus der die Siedlungsstrukturen und Wohntypologien resultieren, aber auch der gegenwärtigen Prozesse der Urbanisierung, die das Erhalten der traditionellen Lebensweise gefährden. Dabei werden verschiedene sozioökonomische, ökologische und technische Aspekte der nomadischen Architektur erforscht: wie wird das Weiden der Herden organisiert, wie beeinfl usst das die Siedlungsstrukturen und Hausformen, wer ist für das Bauen zuständig, wie passt sich das Afar Haus den Klima-Gegebenheiten an und wie wird die lokale Ökologie in Zusammenhang mit verfügbaren Ressourcen balanciert. Anschließend werden die politisch-ökonomische und ökologische Veränderungen in der Region in den letzten Jahrzehnten untersucht, die dazu führten, dass der Zugang zu den der Afar zuvor frei zugänglichen Ressourcen wie Wasser, Weidegebiete und Waldbestand erschwert und im schlimmsten Fall komplett untersagt wird. Die lokalen Nachbarschaftskonfl ikte, die daraus resultieren, fordern konstante Anpassungen der Bewegungsrichtungen und Niederlassungsschemata. Diejenigen, die dadurch ohne Existenzmitteln bleiben sind gezwungen ihr Lebensstil auf ein sesshaftes anzupassen und siedeln sich in urbanen Gebieten an.The main focus of this paper is gaining an anthropological and architectural insight into the lifestyle of Afar pastoralists in Ethiopia, from which habitation forms and housing typologies are derived, as well as into the current processes of urbanization that endanger the preservation of the traditional way of life. Various socio-economic, ecological and technical aspects of nomadic architecture are explored here: how is the pasture of the herds managed, how does it affect the structure of the settlements and choice of dwelling forms, who is responsible for building, how is the Afar House adapted to environmental conditions and how is the local ecology balanced in connection with available resources. Finally, the political, economical and ecological changes in the region over the past decades are investigated, which have made access to the previously much more easily attainable for Afar resources such as water, pasture land and forest very diffi cult and, in the worst case, completely restricted. The local confl icts with neighbors resulting from these, call for constant adjustments to the migration patterns and settling schemes. Those who are left without means are forced to adapt their lifestyle to a sedentary one and settle in urban areas.23

Chromatin regulation of lifespan in C. elegans

The biological basis of lifespan regulation is a subject of intense interest, and epigenetic control of gene expression is thought to play an important role in the ageing process. A library of RNAi clones against chromatin factors was used to screen for their effects on lifespan in C.elegans, utilising microscopic examination of lipofuscin accumulation as a primary biomarker of ageing. A secondary RNAi screen involving full lifespan monitoring confirmed knock-downs of four genes, isw-1, cbp-1, mes-2 and jmjd-3.2, results in extension of lifespan. The use of mutant alleles of these genes also resulted in statistically significant lifespan extension. Intriguingly, three of those genes encode H3K27 modifiers: cbp-1 is an acetyl transferase, whilst mes-2 and jmjd-3.2 are H3K27 methyltransferase and demethylase respectively. Mutation in another gene of the jmjd-3.2 family, utx-1, is also known to have a lifespan prolonging effects by increasing H3K27 methylation on the daf-2 promoter (Jin et al, 2012). In addition to its lifespan effects, utx-1 is also an essential developmental gene. Its role in development has, however, been confirmed to be independent of its demethylase activity (Vandamme et al. 2012) raising questions about the biological significance of UTX-1- mediated H3K27 demethylation. I used a demethylase-dead form of UTX-1 to demonstrate that enzymatic activity is absolutely required for UTX-1 function in lifespan regulation. Intriguingly, it is not just utx-1 loss of function that causes lifespan extension; overexpression of utx-1 from a transgenic array is associated with even more dramatic lifespan extension. Moreover, mes-2 and jmjd-3.2 overexpression also increases the lifespan of transgenic animals. Interestingly, however, lifespan extension driven by overexpression of jmjd-3.2 is not dependent on its demethylase function, suggesting a different mode of action to utx-1. Epistasis analysis suggests that the insulin signalling pathway is a crucial target of regulation for all the factors I identified, but ChIP analysis implies that lifespan extension driven by utx-1 overexpression may involve a different pathway from H3K27me3 regulation at the daf-2 locus. Overall, this work pinpoints H3K27 modifications at key target genes as critical determinants of longevity, and furthermore identifies the crucial importance of the fine balance of factors controlling H3K27 methylation status. </p

Chromatin regulation of lifespan in C. elegans

The biological basis of lifespan regulation is a subject of intense interest, and epigenetic control of gene expression is thought to play an important role in the ageing process. A library of RNAi clones against chromatin factors was used to screen for their effects on lifespan in C.elegans, utilising microscopic examination of lipofuscin accumulation as a primary biomarker of ageing. A secondary RNAi screen involving full lifespan monitoring confirmed knock-downs of four genes, isw-1, cbp-1, mes-2 and jmjd-3.2, results in extension of lifespan. The use of mutant alleles of these genes also resulted in statistically significant lifespan extension. Intriguingly, three of those genes encode H3K27 modifiers: cbp-1 is an acetyl transferase, whilst mes-2 and jmjd-3.2 are H3K27 methyltransferase and demethylase respectively. Mutation in another gene of the jmjd-3.2 family, utx-1, is also known to have a lifespan prolonging effects by increasing H3K27 methylation on the daf-2 promoter (Jin et al, 2012). In addition to its lifespan effects, utx-1 is also an essential developmental gene. Its role in development has, however, been confirmed to be independent of its demethylase activity (Vandamme et al. 2012) raising questions about the biological significance of UTX-1- mediated H3K27 demethylation. I used a demethylase-dead form of UTX-1 to demonstrate that enzymatic activity is absolutely required for UTX-1 function in lifespan regulation. Intriguingly, it is not just utx-1 loss of function that causes lifespan extension; overexpression of utx-1 from a transgenic array is associated with even more dramatic lifespan extension. Moreover, mes-2 and jmjd-3.2 overexpression also increases the lifespan of transgenic animals. Interestingly, however, lifespan extension driven by overexpression of jmjd-3.2 is not dependent on its demethylase function, suggesting a different mode of action to utx-1. Epistasis analysis suggests that the insulin signalling pathway is a crucial target of regulation for all the factors I identified, but ChIP analysis implies that lifespan extension driven by utx-1 overexpression may involve a different pathway from H3K27me3 regulation at the daf-2 locus. Overall, this work pinpoints H3K27 modifications at key target genes as critical determinants of longevity, and furthermore identifies the crucial importance of the fine balance of factors controlling H3K27 methylation status. </p