No description available.

Globally, the forestry sector is the second largest contributor of greenhouse gases, and sustainable forest management is a major target of international environmental policy. However, there is the assumption underlying many policy recommendations that an increase in above-ground carbon stocks correspond to long term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of organic inputs manipulations as part of the Detritus Input and Removal Treatment (DIRT) network. There was no statistically significant effect of the rate of litter or root inputs on the carbon or nitrogen in bulk soil, on respiration rates of soil in laboratory incubations, on the non-hydrolyzed fraction of soil organic matter, or on any organic matter associated with any density. However, there is evidence for positive priming due to increased litter inputs; doubling the rate of litter inputs decreased C and N contents of bulk soil and decreased respiration rates of soil. Furthermore, there is evidence that roots influence soil organic matter dynamics more strongly than above-ground inputs. Both of these results trends match data from other DIRT sites, and are supported by the literature. / Graduation date: 2012

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, toxic contaminants that are released to the environment from various petrogenic and pyrogenic sources. In an effort to more clearly identify and trace sources of PAHs in the environment, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing highly pure extracts using various chromatographic techniques. The method was refined by improving compound separations using purification techniques and high resolution chromatographic columns. The purification method consists of alumina/silica gel column chromatography, gel permeation chromatography and thin layer chromatography. The mean recovery of PAHs after the purification procedure was approximately 80 %. Sample purities after purification were verified by GC/FID and full scan mass spectrometry. To better resolve peaks and provide more accurate stable carbon isotope measurements, various gas chromatographic conditions were evaluated. The precision of the method ranged between 0.08 and 0.43 . The analytical protocols were evaluated to confirm compositional and stable isotopic integrity during purification and stable isotopic analysis. To confirm the utility of the purification and isotope analysis methods, various environmental samples from marine, land and lacustrine environments were analyzed. The isolates were analyzed for the composition and the stable carbon isotope ratios of PAHs. The stable carbon isotope ratio was measured by GC/IRMS and the results, along with quantitative compound compositions, were used to characterize and identify the contaminant sources. The sources of the PAHs in the study areas were differentiated by PAH molecular ratios and confirmed by stable carbon isotope ratios. This study confirms that compound specific isotope analysis of pollutants by GC/IRMS can be used to identify PAH sources in environmental samples. The study also confirms that the purification and stable carbon isotope analysis methods that were developed can be used to accurately measure the stable carbon isotope ratios of PAHs in environmental samples for the purpose of source identification. GC/IRMS measurement of stable isotopic compositions can be an effective fingerprinting method when used in conjunction with traditional molecular composition methods.

Sehzellen von Insekten sind epitheliale Zellen mit einer charakteristischen, hochpolaren Morphologie und Organisation. Die molekularen Komponenten der Sehkaskade befinden sich im Rhabdomer, einem Saum dicht gepackter Mikrovilli entlang der Sehzelle. Bereits in den 70er Jahren des letzten Jahrhunderts wurde beschrieben, dass die Mikrovilli entlang einer Sehzelle eine unterschiedliche Ausrichtung besitzen, oder in anderen Worten, die Rhabdomere entlang der Sehzell-Längsachse verdreht sind. So sind in den Sehzellen R1-R6 bei dipteren Fliegen (Calliphora, Drosophila) die Mikrovilli im distalen und proximalen Bereich eines Rhabdomers etwa rechtwinkelig zueinander angeordnet. Dieses Phänomen wird in der Fachliteratur als rhabdomere twisting bezeichnet und reduziert die Empfindlichkeit für polarisiertes Licht. Es wurde für das Drosophila-Auge gezeigt, dass diese strukturelle Asymmetrie der Sehzellen mit einer molekularen Asymmetrie in der Verteilung phosphotyrosinierter Proteine an die Stielmembran (einem nicht-mikrovillären Bereich der apikalen Plasmamembran) einhergeht. Zudem wurde gezeigt, dass die immuncytochemische Markierung mit anti-Phosphotyrosin (anti-PY) als lichtmikroskopischer Marker für das rhabdomere twisting verwendet werden kann. Bisher wurde hauptsächlich die physiologische Bedeutung der Rhabdomerverdrehung untersucht. Es ist wenig über die entwicklungs- und zellbiologischen Grundlagen bekannt. Ziel der vorliegenden Arbeit war es, die Identität der phosphotyrosinierten Proteine an der Stielmembran zu klären und ihre funktionelle Bedeutung für die Entwicklung des rhabdomere twisting zu analysieren. Zudem sollte untersucht werden, welchen Einfluss die inneren Sehzellen R7 und R8 auf die Verdrehung der Rhabdomere von R1-R6 haben. Für die zwei Proteinkinasen Rolled (ERK) und Basket (JNK) vom Typ der Mitogen-aktivierten Proteinkinasen (MAPK) konnte ich zeigen, dass sie in ihrer aktivierten (= phosphorylierten) Form (pERK bzw. pJNK) eine asymmetrische Verteilung an der Stielmembran aufweisen vergleichbar der Markierung mit anti-PY. Weiterhin wurde diese asymmetrische Verteilung von pERK und pJNK ebenso wie die von PY erst kurz vor Schlupf der Fliegen (bei ca. 90% pupaler Entwicklung) etabliert. Durch Präinkubationsexperimente mit anti-PY wurde die Markierung mit anti-pERK bzw. anti-pJNK unterbunden. Diese Ergebnisse sprechen dafür, dass pERK und pJNK zu den Proteinen gehören, die von anti-PY an der Stielmembran erkannt werden. Da es sich bei ERK und JNK um Kinasen handelt, ist es naheliegend, dass diese an der Entwicklung des rhabdomere twisting beteiligt sein könnten. Diese Hypothese wurde durch die Analyse von hypermorphen (rl SEM)und hypomorphen (rl 1/rl 10a) Rolled-Mutanten überprüft. In der rl SEM-Mutante mit erhöhter Aktivität der Proteinkinase erfolgte die asymmetrische Positionierung von pERK an der Stielmembran sowie die Mikrovillikippung schon zu einem früheren Zeitpunkt in der pupalen Entwicklung. Im adulten Auge war die anti-PY-Markierung im distalen Bereich der Sehzellen intensiver sowie der Kippwinkel vergrößert. In der rl 1/rl 10a-Mutanten mit reduzierter Kinaseaktivität waren die anti-PY-Markierung und der Kippwinkel im proximalen Bereich der Sehzellen verringert. Die Proteinkinase ERK hat somit einen Einfluss auf die zeitliche Etablierung des rhabdomere twisting wie auch auf dessen Ausprägung im Adulttier. Die Rhabdomerverdrehung sowie die Änderung im anti-PY-Markierungsmuster erfolgen an den Sehzellen R1-R6 relativ abrupt auf halber Ommatidienlänge, dort wo das Rhabdomer von R7 endet und das von R8 beginnt. Es stellte sich deshalb die Frage, ob die Rhabdomerverdrehung an R1-R6 durch die Sehzelle R7 und/oder R8 beeinflusst wird. Um dieser Frage nachzugehen wurden Mutanten analysiert, denen die R7- oder die R8-Photorezeptoren bzw. R7 und R8 fehlten. Das wichtigste Ergebnis dieser Untersuchungen war, dass bei Fehlen von R8 die Rhabdomerverdrehung bei R1-R6 nach keinen erkennbaren Regeln erfolgt. R8 ist somit Voraussetzung für die Etablierung der Rhabdomerverdrehung in R1-R6. Folgendes Modell wurde auf Grundlage dieses und weiterer Ergebnisse erarbeitet: Im dritten Larvenstadium rekrutiert R8 die Sehzellpaare R2/R5, R3/R4 und R1/R6. Dabei werden R1-R6 durch den Kontakt zu R8 „polarisiert“. Abschließend wird R7 durch R8 rekrutiert. Dies führt zu einer Fixierung der Polarität von R1-R6 durch R7. Die Ausführung der Mikrovillikippung anhand der festgelegten Polarität erfolgt in der späten Puppenphase. Die Proteinkinase ERK ist an diesem letzten Morphogeneseprozess beteiligt. / Visual cells of insects are epithelial cells with a characteristic morphology and organization. The molecular components of the signalling cascade are arranged in the rhabdomere, an array of densely packed microvilli along the side of the cell body. Already in the 70s of the last century it was described that microvilli point in different directions in various segments of the rhabdomere. Thus, in Dipteran flies (Calliphora, Drosophila) microvilli in the distal part of visual cells R1-R6 are nearly perpendicular to the microvilli in the proximal portion. This phenomenon is termed rhabdomere twisting and decreases the sensitivity of visual cells to polarized light. For Drosophila, structural asymmetry was shown to correlate with molecular asymmetry in the distribution of phosphotyrosinated proteins to the stalk (a non-microvillar region of the apical plasma membrane). Furthermore, this asymmetric distribution of antiphosphotyrosine (anti-PY) provides a light microscopic marker for rhabdomere twisting. So far little is known about the developmental and cell biological basis of rhabdomere twisting. Purpose of the present study was to identify the phosphotyrosinated proteins at the stalk und to analyse their functional relevance for the development of rhabdomere twisting. Moreover, influence of the inner visual cells R7 and R8 on rhabdomere twisting should be examined. Two protein kinases of the MAPK-type, Rolled (ERK) and Basket (JNK), show for their activated (= phosphorylated) forms (pERK and pJNK respectively) an asymmetric distribution to the stalk comparable to labelling with anti-PY. In addition, this asymmetric distribution of pERK, pJNK and also PY is established shortly before eclosion of the fly. Preincubation experiments with anti-PY abolished labelling with anti-pERK and anti-pJNK respectively. These results indicate that pERK and pJNK belong to the proteins on the stalk recognized by anti-PY. ERK and JNK are kinases and therefore are likely to be involved in the development of rhabdomere twisting. To test this hypothesis I analysed hypermorph (rl SEM) and hypomorph (rl 1/rl 10a) rolled mutants. In rl SEM mutants with increased kinase activity asymmetric positioning of pERK to the stalk and tilting of microvilli occurred earlier during pupal development. In the adult eye anti-PY labelling was more intensive in the distal part of the visual cells, and congruently the microvillar tilt angle was increased. In rl 1/rl 10a mutants with reduced kinase activity anti-PY labelling and microvillar tilt angle were reduced in the proximal part of visual cells. Hence, protein kinase ERK has an influence on developmental establishment of rhabdomere twisting and its specification in the adult eye. In R1-R6 rhabdomere twisting as well as changes in anti-PY labelling pattern take place within a narrow range halfway along the rhabdomere where the rhabdomere of R7 ceases and that of R8 begins. So the question arises whether rhabdomere twisting of R1-R6 is influenced by R7 and/or R8. To answer that question I analysed mutants that lack R7 or R8 or both visual cells. Most importantly absence of R8 leads to a disorganized rhabdomere twisting in R1-R6. Consequently R8 seems to be required for the establishment of rhabdomere twisting in R1-R6. Following working model was developed: in the third larval instar R8 recruits pairs of visual cells R2/R5, R3/R4 and R1/R6. In that process R1-R6 become „polarised“ by the contact to R8. Finally R7 is recruited by R8. That fixes polarity of R1-R6 by R7. The active tilting of the microvilli on the basis of the given polarity is carried out in late pupal development with the help of protein kinase ERK.

In this thesis I aim to improve phrase-based statistical machine translation (PBSMT) in a number of ways by the use of text harmonization strategies. PBSMT systems are built by training statistical models on large corpora of human translations. This architecture generally performs well for languages with similar structure. If the languages are different for example with respect to word order or morphological complexity, however, the standard methods do not tend to work well. I address this problem through text harmonization, by making texts more similar before training and applying a PBSMT system. I investigate how text harmonization can be used to improve PBSMT with a focus on four areas: compounding, definiteness, word order, and unknown words. For the first three areas, the focus is on linguistic differences between languages, which I address by applying transformation rules, using either rule-based or machine learning-based techniques, to the source or target data. For the last area, unknown words, I harmonize the translation input to the training data by replacing unknown words with known alternatives. I show that translation into languages with closed compounds can be improved by splitting and merging compounds. I develop new merging algorithms that outperform previously suggested algorithms and show how part-of-speech tags can be used to improve the order of compound parts. Scandinavian definite noun phrases are identified as a problem forPBSMT in translation into Scandinavian languages and I propose a preprocessing approach that addresses this problem and gives large improvements over a baseline. Several previous proposals for how to handle differences in reordering exist; I propose two types of extensions, iterating reordering and word alignment and using automatically induced word classes, which allow these methods to be used for less-resourced languages. Finally I identify several ways of replacing unknown words in the translation input, most notably a spell checking-inspired algorithm, which can be trained using character-based PBSMT techniques. Overall I present several approaches for extending PBSMT by the use of pre- and postprocessing techniques for text harmonization, and show experimentally that these methods work. Text harmonization methods are an efficient way to improve statistical machine translation within the phrase-based approach, without resorting to more complex models.

It has been well known that the architecture of insect compound eyes contributes outstanding capability for precise and efficient observation of moving objects. If this technique can be transferred to the domain of engineering applications, significant improvement on visual tracking of moving objects will be greatly expected. The brightness variation, caused by relative velocity of the camera and environment in a sequence of images, is called optical flow. The advantage of the optical-flow-based visual servo methods is that features of the moving object do not have to be known in advance. Therefore, they can be applied for general positioning and tracking tasks. The purpose of this thesis is to develop a visual servo system with trinocular cameras. For mimicking the configuration of compound eyes of insects, the arrangement of the divergent trinocular cameras is applied. In order to overcome possible difficulties of unknown or uncertain parameters, an image servo technique using the robust discrete-time sliding-mode control algorithm to track an object moving in 2D space is developed.

This thesis aims at exploring how probabilistic reasoning arises in explorative learning situations that are random in nature. The focus is especially on what learners with scant experience of formal theories of probability do and can do when dealing with compound random situations in which they are offered opportunities to integrate different probabilistic lines of reasoning. Three studies were carried out for the purpose of gaining an understanding of how learners’ probabilistic reasoning is organised and re-organised in explorative, random-dependent situations. In two of the studies 12 to 13 year-old students acted within a dice-game setting, which was based on the total of two dice. The third study examined 14 to 16 year-old students’ ways of dealing with ICT-versions of compound, independent events viewed in a random-dependent ramified structure. To uncover the basis and the content of the students’ reasoning, behaviour has been regarded in terms of intentions. That is, to understand and make sense of the students’ reasoning, their activities have been matched and re-matched with conjectures about their intents to fulfil certain goals. Although the students were acting on the same learning material, the analyses revealed various kinds of probabilistic reasoning among the students. It has been argued that students’ various ways of dealing with chance encounters may be understood and explained with reference to the ways in which they interpret the learning situations. Thus, this thesis suggests that probabilistic reasoning takes form through a process of contextualisation, i.e. through a compound process where the cognitive activity oscillates between interpretations and reflections about context, the focal event and new information that comes into play. This thesis reveals that students, prior to instruction, are able to devise ideas of an underlying probability distribution in the case of compound random phenomena. The students bring into the discussion geometrical and numerical considerations, as well as arguments reflecting principles of the law of large numbers.

No description available.

<p>Although monophosphoryl lipid A was recently approved by the Food and Drug Administration, more vaccine adjuvants are needed to meet the demand for vaccines against new, emerging, and re-emerging diseases. Additionally, characterizing the mechanisms of action of potent vaccine adjuvants is important for moving toward more rational vaccine design based on the careful selection of antigens and adjuvants to stimulate only the desired immune responses. Two experimental vaccine adjuvants, compound 48/80 (C48/80) and IL-1, were evaluated in these studies. The safety and efficacy of the mast cell activator C48/80 was evaluated when used as an adjuvant delivered intradermally (ID) with recombinant anthrax protective antigen (rPA) in comparison with two well-known adjuvants. Mice were vaccinated in the ear pinnae with rPA or rPA + C48/80, CpG oligodeoxynucleotides (CpG), or cholera toxin (CT). All adjuvants induced similar increases in serum anti-rPA IgG and lethal toxin-neutralizing antibodies. C48/80 induced balanced cytokine production (Th1/Th2/Th17) by antigen-restimulated splenocytes, minimal injection site inflammation, and no antigen-specific IgE. Our data demonstrate that C48/80 is a safe and effective adjuvant, when used by the intradermal route, to induce protective antibody and balanced Th1/Th2/Th17 responses. Histological analysis demonstrated that vaccination with C48/80 reduced the number of resident mast cells and induced an injection-site neutrophil influx within 24 hours. Nonetheless, rPA + C48/80 significantly increased antigen-specific IgG titers in mast cell-deficient mice compared to antigen alone, suggesting that C48/80 has mast cell-dependent and mast cell-independent mechanisms of action.</p><p>IL-1alpha and beta have been shown to have strong mucosal adjuvant activities, but little is known about their mechanism of action. Bone marrow chimeric mice were intranasally vaccinated with Bacillus anthracis lethal factor (LF) with or without 4 µg IL-1alpha or a control adjuvant (cholera toxin) to determine if IL-1R1 expression on stromal cells or hematopoietic cells was sufficient for the maximal adjuvant activity of nasally delivered IL-1alpha. IL-1alpha was not active in IL-1R1-deficient (<italic>Il1r1</italic>-/-) mice given <italic>Il1r1</italic>-/- bone marrow, demonstrating that the adjuvant activity of IL-1 was due to the presence of IL-1R1 and not contaminants. Cytokine and chemokine responses induced by vaccination with IL-1alpha were predominantly derived from the stromal cell compartment and included G-CSF, IL-6, IL-13, MCP-1, and KC. Nasal vaccination of <italic>Il1r1</italic>-/- mice given wild-type bone marrow (WT-->KO) and WT-->WT mice with LF + IL-1alpha induced maximal adaptive immune responses, while vaccination of wild-type mice given <italic>Il1r1</italic>-/- bone marrow (KO-->WT) mice resulted in significantly decreased production of LF-specific serum IgG, IgG subclasses, lethal toxin-neutralizing antibodies, and mucosal IgA compared to WT-->KO and WT-->WT mice (p < 0.05). Our results suggest that IL-1R1 expression in the hematopoietic compartment is sufficient for the maximal induction of antigen-specific adaptive immunity after nasal vaccination adjuvanted with IL-1alpha and that while stromal cells are required for maximal adjuvant-induced cytokine production, the adjuvant-induced stromal cell cytokine responses are not required for effective induction of adaptive immunity.</p> / Dissertation

Little is known about the enzyme-substrate interactions occurring during the dechlorination of chloroform (CF) and 1,1,1-trichloroethane (1,1,1-TCA) by the enrichment culture containing Dehalobacters, hereafter called DHB-CF/MEL. Compound specific isotope analysis (CSIA) is used to investigate the factors which may affect the isotope fractionation observed for CF and 1,1,1-TCA dechlorination. This thesis reports the first isotope enrichment factors observed for CF biodegradation at -27.5‰ ± 0.9‰, thus providing fundamental information for comparing isotope enrichment factors observed during trichlorinated alkane degradation by DHB-CF/MEL. The thesis also reports how the presence of CF and 1,1,1-TCA influences isotope fractionation and explores the possible influence of substrate inhibition on isotope fractionation during 1,1,1-TCA dechlorination. The data suggests that substrate inhibition during 1,1,1-TCA dechlorination by DHB-CF/MEL may not affect carbon isotope fractionation. The results suggest that CSIA is a promising monitoring tool even for the simultaneous biodegradation of CF and 1,1,1-TCA at different 1,1,1-TCA starting concentration.