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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Floristická studie vodních sinic a řas v jihovýchodní části kraje Vysočina / Floristic study of cyanobacteria and algae in south-east part of Vysočina region

MELICHAR, Antonín January 2011 (has links)
The phytoplankton samples from 45 localities in Vysočina region were collected in 2009. Species composition and relative abundance of species were studied; ecological factors like pH, conductivity, temperature, water transparency and dissolved ions were measured. Ecological indices (Shannon and Simpson index of diversity) were calculated and compared with other ecological factors. Checklist of all species present in Vysočina region was made. There were found 262 species and 4 species new for the Czech Republic.
2

Model Based Analysis of Clonal Developments Allows for Early Detection of Monoclonal Conversion and Leukemia

Baldow, Christoph, Thielecke, Lars, Glauche, Ingmar 28 March 2017 (has links) (PDF)
The availability of several methods to unambiguously mark individual cells has strongly fostered the understanding of clonal developments in hematopoiesis and other stem cell driven regenerative tissues. While cellular barcoding is the method of choice for experimental studies, patients that underwent gene therapy carry a unique insertional mark within the transplanted cells originating from the integration of the retroviral vector. Close monitoring of such patients allows accessing their clonal dynamics, however, the early detection of events that predict monoclonal conversion and potentially the onset of leukemia are beneficial for treatment. We developed a simple mathematical model of a self-stabilizing hematopoietic stem cell population to generate a wide range of possible clonal developments, reproducing typical, experimentally and clinically observed scenarios. We use the resulting model scenarios to suggest and test a set of statistical measures that should allow for an interpretation and classification of relevant clonal dynamics. Apart from the assessment of several established diversity indices we suggest a measure that quantifies the extension to which the increase in the size of one clone is attributed to the total loss in the size of all other clones. By evaluating the change in relative clone sizes between consecutive measurements, the suggested measure, referred to as maximum relative clonal expansion (mRCE), proves to be highly sensitive in the detection of rapidly expanding cell clones prior to their dominant manifestation. This predictive potential places the mRCE as a suitable means for the early recognition of leukemogenesis especially in gene therapy patients that are closely monitored. Our model based approach illustrates how simulation studies can actively support the design and evaluation of preclinical strategies for the analysis and risk evaluation of clonal developments.
3

Exploring patterns of phytodiversity, ethnobotany, plant geography and vegetation in the mountains of Miandam, Swat, Northern Pakistan

Akhtar, Naveed 21 August 2014 (has links)
Das Miandam-Untersuchungsgebiet (35° 1′- 5′ N, 72° 30′-37′ E) liegt in der Swat-Region der Provinz Khyber Pakhtunkhwa (ehemals North West Frontier Province) im nördlichen Pakistan. Die vorliegende Arbeit berücksichtigt sowohl ethnobotanische und pflanzensoziologische Aspekte als auch die Pflanzenartendiversität innerhalb des Gebietes. Aufgrund der hohen Habitatvielfalt weist das Miandam-Gebiet einen großen Reichtum von Medizinalpflanzen auf. Die im Rahmen der Arbeit durchgeführte ethnobotanische Studie dokumentiert das Vorkommen der Medizinalpflanzen sowie deren Nutzung in der Region. Weiterhin wurden die durch Sammlerpräferierten Lebensräume bestimmt und evaluiert inwiefern die Heilpflanzen durch Sammlung und Habitatzerstörung bedroht werden. Insgesamt wurden 106 traditionelle Heilpflanzen aus 54 Pflanzenfamilien verzeichnet. Zu den am häufigsten gefundenen Wuchsformen zählten mehrjährige (43%) und kurzlebige Kräuter (23%), Sträucher (16%) und Bäume (15%). Ein Großteil der untersuchten Heilpflanzen und ihrer Produkte wird zur Behandlung von Magen-Darm-Erkrankungen eingesetzt. Die Produkte werden vorrangig als Sud oder Pulver zubereitet und oral angewendet. Achtzig der 106 traditionellen Heilpflanzen gehören der Gruppe der einheimischen Arten an. Fast 50% der Pflanzenarten treten dabei in synanthroper Vegetation auf, während der Rest in naturnaher Umgebung (z.B. extensiv beweidete Wald- und Graslandbereiche) vorgefunden werden kann. Wälder sind der Ursprung der meisten nicht synanthropen einheimischen Medizinalpflanzen. Drei Arten (Aconitum violaceum, Colchicum luteum, Jasminum humile) können als Folge intensiven Sammelns als bedroht eingestuft werden. Um die pflanzensoziologischen und phytogeografischen Aspekte des Projektes abzudecken wurde die Vegetation des Miandam-Gebietes mit einem Fokus auf Wäldern, Gebüschen und anderen Formationen untersucht. Die Ergebnisse der Vegetationserhebungen wurden mit denen anderer Studien in der weiteren Umgebung des Hindukush-Himalayas verglichen. Weiterhin wurde untersucht inwiefern die Waldökosysteme durch anthropogene Aktivitäten im Untersuchungsgebiet bedroht sind. Die im Gebiet verzeichneten Gefäßpflanzenarten umfassen insgesamt 33 Bäume, 52 Sträucher, 305 Kräuter und 11 Lianen. Basierend auf einer multivariaten Analyse konnten 12 Pflanzengesellschaften identifiziert werden. Die Spanne dieser Gesellschaften reichte von subtropischen semiariden Wäldern mit Ailanthus altissima im Tiefland zu alpinen Rasen von Sibbaldia cuneata durchsetzt mit Juniperus. Die dominierende Vegetation des Untersuchungsgebietes besteht aus von Abies pindrow und Viburnum grandiflorum Wäldern. Eine georeferenzierte Karte der Vegetation erleichtert die Lokalisierung der ökologisch interessanten Vegetation. Artenreichtum und –diversität wurden entlang eines Höhengradienten untersucht. Dazu wurde die Alpha- sowie Beta-Diversität verschiedener Wuchsformtypen bestimmt. Der Artenreichtum aller Gefäßpflanzenarten erreichte sein Maximum zwischen 2200-2500 m. Dagegen zeigte der Artenreichtum der Sträucher einen glockenkurvenartigen Verlauf mit einem Maximum zwischen 2000 und 2200 m. Die höchste Alpha-Diversität der Gefäßpflanzenarten wurde in den tieferen Lagen des Untersuchungsgebietes verzeichnet. Die Beta-Diversität aller Wuchsformtypen zeigte entlang des gesamten Höhengradienten hohe Werte und somit einen starken Artenwechsel. Die Beta-Diversität der Straucharten fluktuiert entlang des Höhengradienten und zeigt damit ein einzigartiges Muster.
4

Avaliação da dinâmica e da diversidade de uma pastagem natural submetida a diferentes distúrbios / Evaluation of dynamics and diversity of a natural pasture under different disturbance

Rossi, Guilherme Ebling 17 February 2009 (has links)
Dynamics of species, families and plant functional types (PFTs), and diversity of a natural grassland submitted or not to burning and grazing, in different relief positions (concave a convex slope) were evaluated. Treatments consisted of the associations of those three factors, in a completely randomized design, with variable number of replicates, from two to five. Rotational grazing were used, with an average occupation period of six days. Grazing animals were from Nelore, Charolais and its crosses. Stocking rate was calculated to obtain between 20 to 35 % of disappearing of forage mass. Diversity was evaluated using Shannon and Simpson index and frequency of species. The analysis of dry matter availability, on the relative participation of main species and the relative frequency of the other species were performed by double sampling. Data were submitted to cluster and ordination analysis and an analysis of variance via randomization tests. With respect to diversity, burned and grazed areas had lower index than those only grazed. Considering relief and grazing interaction, higher diversity occurred in convex slope. Including burning interaction, diversity was higher in concave slope. In grazing excluded areas, higher index were observed under burning effect, and considering this factor, higher diversity were registered in convex slope. Analyzing frequency of families, Poaceae, Cyperaceae and Asteraceae were present in all plots. The most versatile species were A. lateralis, Frimbristylis diphylla and Dichanthelium sabulorum, occurring in all treatments. Burning and grazing had a positive influence in vegetation diversity, however when interacting or in its absence, they turned dynamics to a dominance of a few species. The evaluation of dynamics showed that interpretation of the results through PFTs were more efficient to explore the differences between treatments, when compared to analysis by families or by species. The seasonal dynamics of the vegetation was affected both by grazing, burning and relief position, independently if evaluated through species or functional types of plants. / Foi avaliada a dinâmica por meio de espécies, famílias e tipos funcionais de plantas (TFs), e a diversidade de uma pastagem natural submetida aos fatores queima (presença ou ausência) e pastejo (ausência ou presença), em diferentes posições topográficas (encosta ou baixada). Os tratamentos foram constituídos pela associação dos três fatores, em um delineamento completamente casualizado com número variável de repetições, entre duas e cinco. O pastejo foi rotacionado, com um período de ocupação médio de seis dias, sendo utilizados animais das raças Nelore, Charolês e suas cruzas. A carga foi calculada adotando-se uma taxa de desaparecimento entre 20-35% da massa de forragem existente. A diversidade foi avaliada através dos índices de Shannon, Simpson e da freqüência de ocorrência de espécies. As avaliações da disponibilidade total de matéria seca, da participação relativa das principais espécies e da freqüência relativa das demais espécies foram realizadas por meio de dupla amostragem. Os dados obtidos foram submetidos às análises de agrupamento, ordenação e de variância via teste de aleatorização. Com relação à diversidade, as áreas queimadas com pastejo possuíram índices menores do que apenas com pastejo. Considerando a interação relevo e pastejo, a maior diversidade se deu na encosta. Incluindo-se a interação com o efeito de queima, essa foi superior nas áreas de baixada. Na exclusão de pastejo, os índices mais elevados foram encontrados com queima, e dentro desse distúrbio, maiores índices na posição de relevo de encosta. Já na ausência da queima, o maior índice foi observado na baixada. Na análise da freqüência de ocorrência por família, destacaram-se Poaceae, Cyperaceae e Asteraceae, com presença em todos os ambientes estudados. Já as espécies com maior versatilidade foram A. lateralis, Frimbristylis diphylla e Dichanthelium sabulorum, encontrados em todos os tratamentos avaliados. O emprego da queima ou pastejo tiveram uma influência positiva na diversidade da vegetação, porém quando em conjunto ou totalmente ausentes direcionaram a dinâmica a uma dominância de poucas espécies. O estudo da dinâmica mostrou que a interpretação dos resultados através dos TFs foi mais eficiente para explorar as diferenças entre os tratamentos, quando comparado às análises por famílias botânicas ou por espécies. A dinâmica estacional da vegetação foi afetada pelos fatores pastejo, queima e posição de relevo, independentemente se avaliados através de espécies ou tipos funcionais de plantas.
5

ESTUDO DE COMUNIDADES VEGETAIS CAMPESTRES NA REGIÃO DO ALTO CAMAQUÃ, RIO GRANDE DO SUL / GRASSLAND COMMUNITIES EVALUATION AT ALTO CAMAQUÃ, RIO GRANDE DO SUL

Boavista, Lidiane da Rosa 02 March 2012 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Understanding the dynamics of vegetation could facilitate decision making and adoption of new management practices, seeking a better use of available resources in areas of natural grassland. This study aimed to evaluate the dynamics of a natural grassland vegetation subject to grazing and fertilization, in four different locations in the counties of Pinheiro Machado and Piratini, located in the upper basin region of Rio Camaquã. The treatments were a combination of the above factors. The estimation of species composition and biomass followed BOTANAL field method procedures, with some adjustments. There was a change in vegetation dynamics in the treatments as a response of the interaction of evaluation period, fertilization and grazing, showing a divergence of the trajectories of vegetation and there is no clear distinction of functional types. There was not a clear association between the functional types and environmental variables. The diversity and evenness of species were quantified using the Shannon and equitability indexes. There were no significant differences between different fertilization, but for grazing, there was a significant difference between the evaluation periods. Areas subjected to controlled grazing, show a tendency to increase the diversity of species compared to areas subjected to continuous grazing. The use of controlled grazing had a positive influence on species diversity. / A compreensão da dinâmica vegetacional pode facilitar as tomadas de decisões a adoção de novas práticas de manejo, visando um melhor aproveitamento dos recursos disponíveis em áreas de pastagem natural. Este estudo teve como objetivo avaliar a dinâmica vegetacional de uma pastagem natural submetida aos fatores adubação e pastejo, em quatro locais diferentes, nos municípios de Pinheiro Machado e Piratini, localizados no terço superior da bacia região do Rio Camaquã. Os tratamentos foram constituídos pela associação dos fatores acima. As estimativas da composição de espécies e suas respectivas biomassas seguiram os procedimentos de campo do método BOTANAL, com algumas adaptações. Visando gerar hipóteses sobre os efeitos dos tratamentos, foram utilizadas análises multivariadas para os dados de dinâmica de espécies e tipos funcionais. A diversidade e uniformidade de espécies foram quantificadas através dos índices de Shannon e da equitabilidade. Houve uma mudança na dinâmica vegetacional em função dos efeitos compostos pelos fatores períodos de avaliação, adubação e pastoreio, indicada por uma divergência nas trajetórias da vegetação. Não foi evidenciada uma associação nítida entre os tipos funcionais e as variáveis ambientais. A diversidade e uniformidade de espécies foram quantificadas através dos índices de Shannon e da equitabilidade. Não foram observadas diferenças significativas entre as diferentes adubações, para o pastejo, houve diferença significativa na comparação entre os períodos de avaliação. Áreas submetidas a pastoreio controlado demonstraram uma tendência ao aumento da diversidade de espécies, quando comparadas a áreas submetidas a pastoreio contínuo e sem controle que apresentaram valores menores.
6

Rainfall partitioning and soil water dynamics along a tree species diversity gradient in a deciduous old-growth forest in Central Germany / Niederschlagsverteilung und Bodenwasserdynamik entlang eines Baumartendiversitätsgradienten in einem naturnahen Laubwald in Mitteldeutschland

Krämer, Inga 30 November 2009 (has links)
No description available.
7

Model Based Analysis of Clonal Developments Allows for Early Detection of Monoclonal Conversion and Leukemia

Baldow, Christoph, Thielecke, Lars, Glauche, Ingmar 28 March 2017 (has links)
The availability of several methods to unambiguously mark individual cells has strongly fostered the understanding of clonal developments in hematopoiesis and other stem cell driven regenerative tissues. While cellular barcoding is the method of choice for experimental studies, patients that underwent gene therapy carry a unique insertional mark within the transplanted cells originating from the integration of the retroviral vector. Close monitoring of such patients allows accessing their clonal dynamics, however, the early detection of events that predict monoclonal conversion and potentially the onset of leukemia are beneficial for treatment. We developed a simple mathematical model of a self-stabilizing hematopoietic stem cell population to generate a wide range of possible clonal developments, reproducing typical, experimentally and clinically observed scenarios. We use the resulting model scenarios to suggest and test a set of statistical measures that should allow for an interpretation and classification of relevant clonal dynamics. Apart from the assessment of several established diversity indices we suggest a measure that quantifies the extension to which the increase in the size of one clone is attributed to the total loss in the size of all other clones. By evaluating the change in relative clone sizes between consecutive measurements, the suggested measure, referred to as maximum relative clonal expansion (mRCE), proves to be highly sensitive in the detection of rapidly expanding cell clones prior to their dominant manifestation. This predictive potential places the mRCE as a suitable means for the early recognition of leukemogenesis especially in gene therapy patients that are closely monitored. Our model based approach illustrates how simulation studies can actively support the design and evaluation of preclinical strategies for the analysis and risk evaluation of clonal developments.
8

Quantifying biodiversity trends in time and space

Studeny, Angelika C. January 2012 (has links)
The global loss of biodiversity calls for robust large-scale diversity assessment. Biological diversity is a multi-faceted concept; defined as the “variety of life”, answering questions such as “How much is there?” or more precisely “Have we succeeded in reducing the rate of its decline?” is not straightforward. While various aspects of biodiversity give rise to numerous ways of quantification, we focus on temporal (and spatial) trends and their changes in species diversity. Traditional diversity indices summarise information contained in the species abundance distribution, i.e. each species' proportional contribution to total abundance. Estimated from data, these indices can be biased if variation in detection probability is ignored. We discuss differences between diversity indices and demonstrate possible adjustments for detectability. Additionally, most indices focus on the most abundant species in ecological communities. We introduce a new set of diversity measures, based on a family of goodness-of-fit statistics. A function of a free parameter, this family allows us to vary the sensitivity of these measures to dominance and rarity of species. Their performance is studied by assessing temporal trends in diversity for five communities of British breeding birds based on 14 years of survey data, where they are applied alongside the current headline index, a geometric mean of relative abundances. Revealing the contributions of both rare and common species to biodiversity trends, these "goodness-of-fit" measures provide novel insights into how ecological communities change over time. Biodiversity is not only subject to temporal changes, but it also varies across space. We take first steps towards estimating spatial diversity trends. Finally, processes maintaining biodiversity act locally, at specific spatial scales. Contrary to abundance-based summary statistics, spatial characteristics of ecological communities may distinguish these processes. We suggest a generalisation to a spatial summary, the cross-pair overlap distribution, to render it more flexible to spatial scale.
9

Monitoring anti-infectives and antibiotic resistance genes : with focus on analytical method development, effects of antibiotics and national perspectives

Khan, Ghazanfar Ali January 2012 (has links)
Antibiotics are biologically active and are globally used in humans and animal medicine for treatment and in sub-therapeutic amounts as growth promoters in animal husbandry, aquaculture and agriculture. After excretion, inappropriate disposal and discharge from drug production facilities they enter into water bodies either as intact drugs, metabolites or transformed products. In water environments they promote development of antibiotic resistance genes (ARGs) which could serve as a reservoir and be horizontally transferred to human-associated bacteria and thus contribute to AR proliferation. Measurement of antibiotics has been revolutionized with the usage of solid phase extraction (SPE) for enrichment followed by Liquid chromatography mass spectrometry (LC-MS). On-line SPE coupled to LC-MS/MS has the advantages of high sample throughput, low sample preparation time and minimal solvent utilization.  Constructed wetlands (CWs) are potential alternatives to conventional treatment plants to remove organic pollutants. A study at Plönninge, Halmstad was performed to assess the impact of bacterial community pattern and development of resistance in spiked (n=4) and control (n=4). CWs were spiked with antibiotics at environmentally relevant concentrations continuously for 25 days. Shannon Index (H’) were used to determine the bacterial diversity and real-time PCR detected and quantified antibiotic resistance genes (ARGs) sulI, tetA, tetB, erm, dfrA1, qnrS and vanB and class 1 integrons intI1. No significant differences in bacterial compositions or in ARGs or integron concentrations could be discerned between exposed and control wetlands. A study conducted in Northern Pakistan showed that the antibiotic levels in most studied rivers were comparable to surface water measurements in unpolluted sites in Europe and the US. However, high levels of antibiotics were detected in the river in close vicinity of the 10 million city Lahore, e.g. 4600 ng L−1 sulfamethoxazole. Highest detected levels were at one of the drug formulation facilities, with measured levels up to 49000 ng L−1 of sulfamethoxazole for example. The highest levels of ARGs detected, sul1 and dfrA1, were directly associated with the antibiotics detected at the highest concentrations, sulfamethoxazole and trimethoprim. In the study in UK, sewage epidemiology surveillance is used to measure the oseltamivir carboxylate (OC), metabolite of oseltamivir (parent drug) in twenty four time proportional hourly influent samples from two WWTPs and then back-calculations were made to assess the compliance of drug.  Predicted users of oseltamivir, based on measured OC in waste water, ranged from 3-4 and 120-154 people for the two WWTP catchments, respectively, which are consistent with the projected use from national antiviral allocation statistics, 3-8 and 108-270, respectively. Scenario analysis suggests compliance was likely between 45-60% in the study regions.

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