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In probabilistic seismic-hazard analysis, epistemic uncertainties are commonly treated within a logic-tree framework in which the branch weights express the degree of belief of an expert in a set of models. For the calculation of the distribution of hazard curves, these branch weights represent subjective probabilities. A major challenge for experts is to provide logically consistent weight estimates (in the sense of Kolmogorovs axioms), to be aware of the multitude of heuristics, and to minimize the biases which affect human judgment under uncertainty. We introduce a platform-independent, interactive program enabling us to quantify, elicit, and transfer expert knowledge into a set of subjective probabilities by applying experimental design theory, following the approach of Curtis and Wood (2004). Instead of determining the set of probabilities for all models in a single step, the computer-driven elicitation process is performed as a sequence of evaluations of relative weights for small subsets of models. From these, the probabilities for the whole model set are determined as a solution of an optimization problem. The result of this process is a set of logically consistent probabilities together with a measure of confidence determined from the amount of conflicting information which is provided by the expert during the relative weighting process. We experiment with different scenarios simulating likely expert behaviors in the context of knowledge elicitation and show the impact this has on the results. The overall aim is to provide a smart elicitation technique, and our findings serve as a guide for practical applications.
The dynamics of tail-like current sheets under the influence of small-scale plasma turbulence
(1999)
A 2D-magnetohydrodynamic model of current-sheet dynamics caused by anomalous electrical resistivity as result of small-scale plasma turbulence is proposed. The anomalous resistivity is assumed to be proportional to the square of the gradient of the magnetic pressure as may be valid for instance in the case of lower-hybrid-drift turbulence. The initial resistivity pulse is given. Then the temporal and spatial evolution of the magnetic and electric fields, plasma density, pressure, convection and resistivity are considered. The motion of the induced electric field is discussed as indicator of the plasma disturbances. The obtained results found using much improved numerical methods show a magnetic field evolution with x-line formation and plasma acceleration. Besides, in the current sheet, three types of magnetohydrodynamic waves occur, fast magnetoacoustic waves of compression and rarefaction as well as slow magnetoacoustic waves.
The author's recently published monograph on Alexander von Humboldt[1] describes the multiple images of this great cultural icon. The book is a metabiographical study that shows how from the middle of the nineteenth century to the present day Humboldt has served as a nucleus of crystallisation for a variety of successive socio-political ideologies, each producing its own distinctive representation of him. The historiographical implications of this biographical diversity are profound and support current attempts to understand historical scholarship in terms of memory cultures.
Die Entstehung der modernen britischen Nachrichtendienstarchitektur fiel in die erste Hälfte des zwanzigsten Jahrhunderts. Zeitgleich erfuhr die britische Gesellschaft eine nie dagewesene Demokratisierung. Die Arbeit versucht darzulegen, wie auch vermeintlich arkane Bereiche staatlichen Handelns in öffentliche Aushandlungsprozesse eingebettet sind und rekonstruiert deshalb erstmals systematisch öffentliche und fachöffentliche Diskurse über Nachrichtendienste Großbritanniens im Zeitalter der Weltkriege.
Same but different
(2022)
The peace processes in Liberia and Sierra Leone share similar contexts and have an interrelated history. They are also often portrayed as successful cases of peacebuilding. This conclusion seems valid, as war has not returned, and political power was handed over peacefully; however, both cases differ with regard to the inclusiveness of the peace processes and the role of local leaders. This article aims to add to the critical peacebuilding debate by focusing on local perceptions about the position of local leaders in these two peace processes. We conducted a public opinion survey in five regions in Sierra Leone and Liberia and expert interviews with peacebuilding actors to examine changing perceptions about the roles of local leaders in both countries. This article speaks to the broader peacebuilding debate by highlighting the importance of including local voices in the peace process and by discussing challenges of inclusive peacebuilding.
Der Beitrag beleuchtet jüngere Entwicklungen der unbefugten Verwendung von Daten im Sinne des § 263 a StGB und versucht, die unterschiedlichen Strömungen beispielsnah einzufangen, um die Schwierigkeiten des Computerbetrugs in der Fallbehandlung aufzuzeigen sowie davon ausgehend darzulegen, wie die eigene Meinung in der Klausur argumentativ zu stützen ist.
Der Beitrag knüpft unmittelbar an den in JA 10/2022, 830 ff. veröffentlichten ersten Teil (Anwendungsbereich, Stufenverhältnisse und unechte Wahlfeststellung) an und führt diesen fort. Idealerweise führen Sie sich zum Einstieg noch einmal die unechte Wahlfeststellung vor Augen, um die Unterschiede zu vergegenwärtigen: Diese ist zu treffen, wenn unklar ist, durch welche von mehreren nach den Erkenntnissen möglichen Handlungen der Täter den identischen Straftatbestand verwirklicht hat – also der Straftatbestand klar, lediglich die diesen erfüllende Handlung unklar ist.
Wenn auch der Begriff ab und an anklingt, so fristet der Nötigungsnotstand doch weitgehend ein Schattendasein in der juristischen Ausbildung. Dabei wartet er in der Klausur mit zahlreichen Problemen auf, welche von der mittelbaren Täterschaft über eine Rechtfertigung oder Entschuldigung bis hin zu einem Erlaubnistatbestandsirrtum reichen können. Bereits deshalb dürfte der Nötigungsnotstand viele Klausurersteller in Versuchung führen – und viele Studierende in die Verzweiflung treiben. Dieser Beitrag will daher die klausurrelevanten Problemkreise des Nötigungsnotstands darstellen, um so Sicherheit für die Klausurbearbeitung zu gewinnen.
Whole-genome duplications (WGDs) or polyploidy events have been studied extensively in plants. In a now widely cited paper, Jiao et al. presented evidence for two ancient, ancestral plant WGDs predating the origin of flowering and seed plants, respectively. This finding was based primarily on a bimodal age distribution of gene duplication events obtained from molecular dating of almost 800 phylogenetic gene trees. We reanalyzed the phylogenomic data of Jiao et al. and found that the strong bimodality of the age distribution may be the result of technical and methodological issues and may hence not be a "true" signal of two WGD events. By using a state-of-the-art molecular dating algorithm, we demonstrate that the reported bimodal age distribution is not robust and should be interpreted with caution. Thus, there exists little evidence for two ancient WGDs in plants from phylogenomic dating.
Large-scale co-expression approach to dissect secondary cell wall formation across plant species
(2011)
Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA) complexes. Several studies in Arabidopsis have demonstrated the power of co-expression analyses to identify new genes associated with secondary wall cellulose biosynthesis. However, across-species comparative co-expression analyses remain largely unexplored. Here, we compared co-expressed gene vicinity networks of primary and secondary wall CESAsin Arabidopsis, barley, rice, poplar, soybean, Medicago, and wheat, and identified gene families that are consistently co-regulated with cellulose biosynthesis. In addition to the expected polysaccharide acting enzymes, we also found many gene families associated with cytoskeleton, signaling, transcriptional regulation, oxidation, and protein degradation. Based on these analyses, we selected and biochemically analyzed T-DNA insertion lines corresponding to approximately twenty genes from gene families that re-occur in the co-expressed gene vicinity networks of secondary wall CESAs across the seven species. We developed a statistical pipeline using principal component analysis and optimal clustering based on silhouette width to analyze sugar profiles. One of the mutants, corresponding to a pinoresinol reductase gene, displayed disturbed xylem morphology and held lower levels of lignin molecules. We propose that this type of large-scale co-expression approach, coupled with statistical analysis of the cell wall contents, will be useful to facilitate rapid knowledge transfer across plant species.
Phytoplankton biomass and production regulates key aspects of freshwater ecosystems yet its variability and subsequent predictability is poorly understood. We estimated within-lake variation in biomass using high-frequency chlorophyll fluorescence data from 18 globally distributed lakes. We tested how variation in fluorescence at monthly, daily, and hourly scales was related to high-frequency variability of wind, water temperature, and radiation within lakes as well as productivity and physical attributes among lakes. Within lakes, monthly variation dominated, but combined daily and hourly variation were equivalent to that expressed monthly. Among lakes, biomass variability increased with trophic status while, within-lake biomass variation increased with increasing variability in wind speed. Our results highlight the benefits of high-frequency chlorophyll monitoring and suggest that predicted changes associated with climate, as well as ongoing cultural eutrophication, are likely to substantially increase the temporal variability of algal biomass and thus the predictability of the services it provides.
Ländliche Gesellschaft im Notstand. Die Ämter Besigheim und Bietigheim im Dreißigjährigen Krieg
(2012)
Der Arbeitskreis Militär und Gesellschaft in der Frühen Neuzeit e. V. wurde im Frühjahr 1995 gegründet. Er hat es sich zur Aufgabe gemacht, die Erforschung des Militärs im Rahmen der frühneuzeitlichen Geschichte zu befördern und zugleich das Bewusstsein der Frühneuzeit-HistorikerInnen für die Bedeutung des Militärs in all seinen Funktionen zu wecken. Das Militär steht somit als soziale Gruppe selbst im Mittelpunkt der Aktivitäten des Arbeitskreises, wird aber auch in seinen Wirkungen und Repräsentationen thematisiert. Ziel ist es, die Rolle des Militärs als Teil der frühneuzeitlichen Gesellschaft umfassend herauszuarbeiten und zu würdigen. Insofern versteht der AMG seine Arbeit nicht nur als Beitrag zur Militärgeschichte, sondern vor allem als Beitrag zur Geschichte der Frühen Neuzeit insgesamt.
Der Arbeitskreis bietet ein Diskussions- und Informationsforum durch die Organisation von Tagungen, die Herausgabe der Schriftenreihe ‚Herrschaft und soziale Systeme in der Frühen Neuzeit‘, die Zeitschrift ‚Militär und Gesellschaft in der Frühen Neuzeit‘ und die Mailingliste mil-fnz.
Außenpolitik ist von den Werten, dem Selbstverständnis einer Gesellschaft und den ökonomischen Interessen ihrer Volkswirtschaft geprägt. In den ersten beiden Teilen dieses Essays zeigen wir auf, wie Deutschland seine Werte behutsam erneuern sollte und welche Bereiche zur Wahrung seines ökonomischen Wohlstands zentral sind. Auf dieses Fundament setzen wir ein Plädoyer für eine neue außenpolitische Kultur, die Interessen offen debattiert und klar definiert, um sie erfolgreich durchzusetzen.
Inhalt: 1. Werte und Selbstverständnis behutsam erneuern Globalisierung Demografischer Wandel Klimawandel 2. Langfristig ökonomischen Wohlstand sichern Bildung Forschung und Entwicklung Außenwirtschaft 3. Plädoyer für eine neue außenpolitische Kultur : Deutsche Interessen – Ein Anachronismus? Status quo: Interessendefinition im Hinterzimmer Interessen klar definieren und erfolgreich durchsetzen Entscheidungsmatrix für Auslandseinsätze Evaluierung des Nutzens Evaluierung der Kosten Ableiten der Entscheidung Und die Moral? – Aber sicher! Der Tönissteiner Kreis
Deutsche Interessen
(2011)
Das Preußische Erbrecht in der Judikatur des Berliner Obertribunals in den Jahren 1836 bis 1865
(2019)
Die Dissertation befasst sich mit dem Allgemeinen Preußischen Landrecht von 1794 und der hierzu ergangenen Rechtsprechung des Berliner Obertribunals. Im Fokus der Untersuchung stehen die erbrechtlichen Regelungen des Landrechts und deren Anwendung sowie Auslegung in der Judikatur des höchsten preußischen Gerichts. Der Forschungsgegenstand ergibt sich aus dem im Landrecht kodifizierten speziellen Gesetzesverständnisses. Nach diesem sollte die Gesetzesauslegung durch die Rechtsprechung auf ein Minimum, nämlich die Auslegung allein anhand des Wortlauts der Regelung reduziert werden, um dem absolutistischen Regierungsanspruch der preußischen Monarchen, namentlich Friedrich des Großen, hinreichend Rechnung zu tragen. In diesem Kontext wird der Frage nachgegangen, inwieweit das preußische Obertribunal das im Landrecht statuierte „Auslegungsverbot“ beachtet hat und in welchen Fällen sich das Gericht von der Vorgabe emanzipierte und weitere Auslegungsmethoden anwendete und sich so eine unabhängige Rechtsprechung entwickeln konnte.
Die Arbeit gliedert sich in drei Hauptabschnitte. Im Anschluss an die Einleitung, in der zunächst die rechtshistorische Bedeutung des Landrechts und des Erbrechts sowie der Untersuchungsgegenstand umrissen werden, folgt die Darstellung der Entstehungsgeschichte des Landrechts und des Berliner Obertribunals.
Hieran schließt sich in einem dritten Abschnitt eine Analyse der erbrechtlichen Vorschriften des Landrechts an. In dieser wird auf die Entstehungsgeschichte der verschiedenen erbrechtlichen Institute wie beispielsweise der gesetzlichen und gewillkürten Erbfolge, dem Pflichtteilsrecht etc., unter Berücksichtigung des zeitgenössischen wissenschaftlichen Diskurses eingegangen.
Im vierten Abschnitt geht es um die Judikate des Berliner Obertribunals aus den Jahren 1836-1865 in denen die zuvor dargestellten erbrechtlichen Regelungen entscheidungserheblich waren. Dabei wird der Forschungsfrage, inwieweit das Obertribunal das im Landrecht statuierte Auslegungsverbot beachtet hat und in welchen Fällen es von diesem abwich bzw. weitere Auslegungsmethoden anwendete, konkret nachgegangen wird. Insgesamt werden 26 Entscheidungen des Obertribunals unter dem Aspekt der Auslegungspraxis, der Kontinuität und der Beschleunigung der Rechtsprechung analysiert und ausgewertet.
During life bones constantly adapt their structure to their mechanical environment via a mechanically controlled process called bone remodeling. For trabecular bone, this process modifies the thickness of each trabecula leading occasionally to full resorption. We describe the irreversible dynamics of the trabecular thickness distribution (TTD) by means of a Markov chain discrete in space and time. By using thickness data from adult patients, we derive the transition probabilities in the chain. This allows a quantification, in terms of geometrical quantities, of the control of bone remodeling and thus to determine the evolution of the TTD with age.
The economy in Poland has changed tremendously in recent years. Agricultural enterprises can defend their market share only if they are able to adjust quickly and efficiently to new circumstances. The most effective strategy to cope with changing operating conditions is a strategy of permanent development of human resources. This strategy must embrace a constant improvement of professional entrepreneurial skills and of management structures within organizations. Only such a strategy will allow businesses to hold on to or to increase their market standing despite strong competition. It will also allow them to meet, for instance, the newly introduced standardisation procedures for goods produced and supplied. This challenge holds especially true for agricultural enterprises that operate in highly competitive markets; markets which are currently characterised by a permanent surplus of supply over demand and a great number of businesses, mainly of small or medium size. Demand in the agricultural market is exerted by millions of consumers, all of different consumption habits with idiosyncratic consumption preferences. Agricultural producers as a group are extremely sensitive to any kind of change in their environment. This is especially true in the current transition period when a worsening of economic conditions can be observed: an economic downturn caused by the price of inputs increasing at a faster rate than agricultural product prices and an ineffective agricultural policy. One of the agricultural production factors which allows for quick adjustment to change and which can thus be used to improve one’s market position is the human factor. It is a wellknown fact that a good level of professional skills in combination with ongoing means of furthering and updating professional qualifications of workers can help to facilitate coping with market challenges. The aim of this study is first to determine specific quality and quantity features of human resources in agricultural production, looking, inter alia, at changes in employment, specific employment structures and the number of recruitments and dismissals in a given period. A further aim was to undertake an efficiency analysis of limited partnerships which leased their agricultural real estate from the Agricultural Property Agency (APA) in the Voivodeship of Gorzów between 1995 and 1997. The first analysis was carried out using data which were collected from surveys amongst the owners of 36 privately owned farms and the managers of 14 limited partnerships. The data cover the period between 1994 and 1997. The incentive to conduct research on large farms in the Gorzów Voivodeship using the Data Envelopment Analysis method (DEA) lay in the outcome of various earlier studies on the financial standing of limited partnerships leasing real estate from APA in the Gorzów Voivodeship in 1996 and 1997. Apart from general adjustment processes, these inquiries proved that, in 1997, the economic condition of the farms analysed was worse when compared to the situation in 1996; the following ratios worsened: the financial support ratio, the liquidity ratio, the turnover ratio, the profitability ratio and the cost level ratio (see Świtłyk, 1998, 1999). These results determined the focus of our research, namely input efficiency in particular limited partnerships. The base of our calculations was a research model which consisted of efficiency measures focusing on firms’ inputs The analysis was carried out on a sample of 90 firms in the years between 1995 and 1997 (30 firms every year). Other data material was collected from national statistical office reports on incomes, costs and financial results (F-O1) and statistics about land usage, crop area and yields (R-O5). In the next section we briefly discuss privatisation in agriculture. Sections 3 and 4 present results from our survey. Section 5 concludes.
It was not until the 1960s and 70s of the 20th century that researchers turned their special interest to colloquial Russian (hereafter CR) and its interaction with codified (normative) Russian. Colloquial Russian uses its grammatical constructions in deviation from the norms of the written language. Since codified language is the basis of colloquial language on the grammatical level, among others, the question arises, how the standard forms are used in oral speech. Lapteva (1976) has looked in particular at the syntax of CR and made a classification of CR constructions that differ from their standard forms. The present study deals with two constructions from this classification: an embedded temporal subordinate clause and a temporal subordinate clause with the meaningless conjunction kogda (as/if), which leaves its normative position in the sentence. In addition to the special forms of temporal adverbial clauses, the frequency of their standard implementation as preceding and the following constructions will be examined. Two hypotheses were formulated:
• The frequency of certain constructions classified by Lapteva (1976) as transitional constructions decreases over decades.
• The ratio between prefixed and suffixed temporal subordinate clauses will be in favor of the latter due to the spontaneity of oral speech. The corpus study was conducted with the oral language sub-corpus of the National'nyj Korpus Russkogo Jazyka (National Corpus of the Russian Language). No evidence of a correlation between the number of CR constructions and the year of recording was found either in the whole oral sub-corpus or in its largest section - the collection of private conversations. The proportion of prefixed temporal constructions was greatest in both public and non-public corpora compared to postfixed ones. The study did not provide evidence for the hypotheses put forward, due to the limitations of the corpus study, such as missing or incomplete context of the conversations, lack of punctuation and/or marking of intonation.
Colliding Wolf-Rayet (WR) winds produce thermal X-ray emission widely observed by X-ray telescopes. In wide WR+O binaries, such as WR 140, the X-ray flux is tied to the orbital phase, and is a direct probe of the winds’ properties. In the Galactic center, ~30 WRs orbit the super massive black hole (SMBH) within ~10”, leading to a smorgasbord of wind-wind collisions. To model the X-ray emission of WR 140 and the Galactic center, we perform 3D hydrodynamic simulations to trace the complex gaseous flows, and then carry out 3D radiative transfer calculations to compute the variable X-ray spectra. The model WR 140 RXTE light curve matches the data well for all phases except the X-ray minimum associated with periastron, while the model spectra agree with the RXTE hardness ratio and the shape of the Suzaku observations throughout the orbit. The Galactic center model of the Chandra flux and spectral shape match well in the region r ≤ 3”, but the model flux falls off too rapidly beyond this radius.
It is desirable to reduce the potential threats that result from the variability of nature, such as droughts or heat waves that lead to food shortage, or the other extreme, floods that lead to severe damage. To prevent such catastrophic events, it is necessary to understand, and to be capable of characterising, nature's variability. Typically one aims to describe the underlying dynamics of geophysical records with differential equations. There are, however, situations where this does not support the objectives, or is not feasible, e.g., when little is known about the system, or it is too complex for the model parameters to be identified. In such situations it is beneficial to regard certain influences as random, and describe them with stochastic processes. In this thesis I focus on such a description with linear stochastic processes of the FARIMA type and concentrate on the detection of long-range dependence. Long-range dependent processes show an algebraic (i.e. slow) decay of the autocorrelation function. Detection of the latter is important with respect to, e.g. trend tests and uncertainty analysis. Aiming to provide a reliable and powerful strategy for the detection of long-range dependence, I suggest a way of addressing the problem which is somewhat different from standard approaches. Commonly used methods are based either on investigating the asymptotic behaviour (e.g., log-periodogram regression), or on finding a suitable potentially long-range dependent model (e.g., FARIMA[p,d,q]) and test the fractional difference parameter d for compatibility with zero. Here, I suggest to rephrase the problem as a model selection task, i.e.comparing the most suitable long-range dependent and the most suitable short-range dependent model. Approaching the task this way requires a) a suitable class of long-range and short-range dependent models along with suitable means for parameter estimation and b) a reliable model selection strategy, capable of discriminating also non-nested models. With the flexible FARIMA model class together with the Whittle estimator the first requirement is fulfilled. Standard model selection strategies, e.g., the likelihood-ratio test, is for a comparison of non-nested models frequently not powerful enough. Thus, I suggest to extend this strategy with a simulation based model selection approach suitable for such a direct comparison. The approach follows the procedure of a statistical test, with the likelihood-ratio as the test statistic. Its distribution is obtained via simulations using the two models under consideration. For two simple models and different parameter values, I investigate the reliability of p-value and power estimates obtained from the simulated distributions. The result turned out to be dependent on the model parameters. However, in many cases the estimates allow an adequate model selection to be established. An important feature of this approach is that it immediately reveals the ability or inability to discriminate between the two models under consideration. Two applications, a trend detection problem in temperature records and an uncertainty analysis for flood return level estimation, accentuate the importance of having reliable methods at hand for the detection of long-range dependence. In the case of trend detection, falsely concluding long-range dependence implies an underestimation of a trend and possibly leads to a delay of measures needed to take in order to counteract the trend. Ignoring long-range dependence, although present, leads to an underestimation of confidence intervals and thus to an unjustified belief in safety, as it is the case for the return level uncertainty analysis. A reliable detection of long-range dependence is thus highly relevant in practical applications. Examples related to extreme value analysis are not limited to hydrological applications. The increased uncertainty of return level estimates is a potentially problem for all records from autocorrelated processes, an interesting examples in this respect is the assessment of the maximum strength of wind gusts, which is important for designing wind turbines. The detection of long-range dependence is also a relevant problem in the exploration of financial market volatility. With rephrasing the detection problem as a model selection task and suggesting refined methods for model comparison, this thesis contributes to the discussion on and development of methods for the detection of long-range dependence.
Taking inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite were investigated. A new preparation approach based on a co-precipitation method has been developed. In its earlier stage of formation, the composite occurs as hydrogel as suspended in aqueous alkaline solution. In order to get solid composites various drying procedures including freeze-drying technique, air-drying at room temperature and at moderate temperatures, between 50oC and 100oC were used. Physicochemical studies showed that the composites exhibit different properties with respect to their structure and composition. IR and Raman spectroscopy probed the presence of both chitosan and hydroxyapatite in the composites. Hydroxyapatite as dispersed in the chitosan matrix was found to be in the nanosize range (15-50 nm) and occurs in a bimodal distribution with respect to its crystallite length. Two types of distribution domains of hydroxyapatite crystallites in the composite matrix such as cluster-like (200-400 nm) and scattered-like domains were identified by the transmission electron microscopy (TEM), X-ray diffraction (XRD) and by confocal scanning laser microscopy (CSLM) measurements. Relaxation NMR experiments on composite hydrogels showed the presence of two types of water sites in their gel networks, such as free and bound water. Mechanical tests showed that the mechanical properties of composites are one order of magnitude less than those of compact bone but comparable to those of porous bone. The enzymatic degradation rates of composites showed slow degradation processes. The yields of degradation were estimated to be less than 10% by loss of mass, after incubation with lysozyme, for a period of 50 days. Since the composite materials were found biocompatible by the in vivo tests, the simple mode of their fabrication and their properties recommend them as potential candidates for the non-load bearing bone substitute materials.
This paper presents some results concerning the size-controlled hydroxyapatite nanoparticles obtained in aqueous media in a biopolymer matrix from soluble precursors salts. Taking the inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite was investigated. A stepwise co-precipitation approach was used to obtain different types of composites by means of different ratio between components. The synthesis of hydroxyapatite was carried out in the chitosan matrix from calcium chloride and sodium dihydrogenphosphate in alkaline solutions at moderate pH of 10-11 for 24 h. Our research is focused on studying and understanding the structure of this class of composites, aiming at the development of novel materials, controlled at the nanolevel scale. The X-ray diffraction technique was employed in order to study the kinetic of hydroxyapatite formation in the chitosan matrix as well as to determine the HAp crystallite sizes in the composite samples. The hydroxyapatite synthesized using this route was found to be nano-sized (15-50nm). Moreover, applying an original approach to analyze the (002) XRD diffraction peak profile of hydroxyapatite by using a sum of two Gauss functions, the bimodal distribution of nanosized hydroxyapatite within the chitosan matrix was revealed. Two types of size distribution domains such as cluster-like (between 200 and 400 nm), which are the habitat of "small" hydroxyapatite nanocrystallites and scattered-like, which are the habitat of "large" hydroxyapatite nanocrystallites was probed by TEM and CSLM. The structural features of composites suggest that self-assembly processes might be involved. The composites contain nanosized hydroxyapatite with structural features close to those of biological apatites that make them attractive for bone tissue engineering applications. (c) 2005 Elsevier Ltd. All rights reserved
Methylmercury (MeHg), an abundant environmental pollutant, has long been known to adversely affect neurodevelopment in both animals and humans. Several reports from epidemiological studies, as well as experimental data indicate sex-specific susceptibility to this neurotoxicant; however, the molecular bases of this process are still not clear. In the present study, we used Caenorhabditis elegans (C. elegans), to investigate sex differences in response to MeHg toxicity during development. Worms at different developmental stage (L1, L4, and adult) were treated with MeHg for 1h. Lethality assays revealed that male worms exhibited significantly higher resistance to MeHg than hermaphrodites, when at L4 stage or adults. However, the number of worms with degenerated neurons was unaffected by MeHg, both in males and hermaphrodites. Lower susceptibility of males was not related to changes in mercury (Hg) accumulation, which was analogous for both wild-type (wt) and male-rich him-8 strain. Total glutathione (GSH) levels decreased upon MeHg in him-8, but not in wt. Moreover, the sex-dependent response of the cytoplasmic thioredoxin system was observedmales exhibited significantly higher expression of thioredoxin TRX-1, and thioredoxin reductase TRXR-1 expression was downregulated upon MeHg treatment only in hermaphrodites. These outcomes indicate that the redox status is an important contributor to sex-specific sensitivity to MeHg in C. elegans.
Methylmercury (MeHg) is an environmental pollutant linked to many neurological defects, especially in developing individuals. The thioredoxin (TRX) system is a key redox regulator affected by MeHg toxicity, however the mechanisms and consequences of MeHg-induced dysfunction are not completely understood. This study evaluated the role of the TRX system in C. elegans susceptibility to MeHg during development. Worms lacking or overexpressing proteins from the TRX family were exposed to MeHg for 1 h at different developmental stage: L1, L4 and adult. Worms without cytoplasmic thioredoxin system exhibited age-specific susceptibility to MeHg when compared to wild-type (wt). This susceptibility corresponded partially to decreased total glutathione (GSH) levels and enhanced degeneration of dopaminergic neurons. In contrast, the overexpression of the cytoplasmic system TRX-1/TRXR-1 did not provide substantial protection against MeHg. Moreover, transgenic worms exhibited decreased protein expression for cytoplasmic thioredoxin reductase (TRXR-1). Both mitochondrial thioredoxin system TRX-2/TRXR-2, as well as other thioredoxin-like proteins: TRX-3, TRX-4, TRX-5 did not show significant role in C. elegans resistance to MeHg. Based on the current findings, the cytoplasmic thioredoxin system TRX-1/TRXR-1 emerges as an important age-sensitive protectant against MeHg toxicity in C. elegans.
Dissecting the tree of life
(2021)
Die Esche ist nicht nur als Weltenbaum Yggdrasil aus der germanischen Mythologie bekannt. Ihr Holz wird für Möbel, Parkett und Werkzeuge genutzt, und sie ist ein wichtiger Faktor für die Neuaufforstung. Doch die Esche ist vom Aussterben bedroht. Das Eschentriebsterben wird ausgelöst durch einen Pilz (Falsches Weißes Stengelbecherchen) und verursacht ein großflächiges Absterben von Altbeständen und jungen Bäumen in allen Teilen Deutschlands.
Diese umweltsoziologische Untersuchung geht der Frage nach, ob die Diskrepanz zwischen der gesellschaftlichen, ökonomischen und ökologischen Bedeutung dieser Baumgattung und ihrem möglichen Verlust zu gesellschaftlichen Diskussionsprozessen über die Esche und das Eschentriebsterben führt.
Anhand der Wissenssoziologischen Diskursanalyse und der Grounded Theory Method wird gezeigt, dass sich zwar Expertinnen und Experten einig sind, dass die Esche vermutlich aussterben wird, ihre gesellschaftliche Bedeutung jedoch nicht groß genug ist, sodass ihr Aussterben als hinreichend problematisch eingestuft wird und folglich politische Handlungskonsequenzen gefordert werden.
Between history and legend
(2010)
In the early modern period, Jewish historiography moved from the Hebrew domain into the Yiddish one. Jewish writers have succeeded to match the historical literature to the particular needs of their audience. The most popular Yiddish chronicle of this kind was written in Amsterdam in the 18th century by Menachem Man Amelander, following both the Jewish and Christian genre. This paper briefly surveys the genre characteristics of this chronicle and the way it served the purpose of guarding Jewish memory and tradition.