This dissertation demonstrates the construction of the Panthera Population Persistence (PPP), an individual-based model for the Sumatran tiger (Panthera tigris sumatrae) which provides proper theoretical and application frameworks for the conservation of this tiger sub-species in central Sumatra. The PPP model was developed to gain insight into tiger-preyhabitat relationships as well as the effect of human impacts on the persistence of tiger populations. The model addresses three main problems for the survival of the Sumatran tiger: tiger poaching, prey depletion, and habitat loss. The description of the PPP model serves as an in-depth study of existing literature and covers the most important factors of existing models for tiger conservation. Existing modelling approaches have been improved by the inclusion of finer description of individual-level traits and behaviours in the PPP model. The modelling approach allows a direct inter-relationships between individuals and their environment. The relationship between individual behaviours, intrinsic states, and external factors are simulated spatially explicitly in a bottom-up approach where the emergence of the population dynamics of tiger and prey can be observed under different scenarios. The integration between the PPP model and geographical information system (GIS) has provided a much more meaningful spatial data by revealing the mechanism of the response of individuals to the present land-use types. The relative importance of the parameters within the PPP model was tested using two modes of sensitivity analysis: The Morris Method and the traditional One-factor-at-a-time method. The results provided guidance for the application of reasonable sensitivity analysis during the development of individual-based models. The Morris Method suggested that the overall output of the PPP model showed a high sensitivity on the change of time required by a tigress to take care of cubs. The analysis also revealed that the number of dispersers was sensitive toward perceptual distance of individuals to detect the presence of prey. Comparison with a similar predator-prey models provided insight into the predator-prey relationship. The comparison also suggested that perceptual distance of the individual is important for any spatially explicit individual-based model involving predator-prey relationships. The parameterization of the individual perceptual distance of tigers was tested by using existing literature on prey consumption by tigers as a benchmark. The simulation results were within the range of scientific acceptance for the number of prey killed by a tiger. Thus, further use of the set of parameters for a tiger’s perceptual distance is less uncertain for the output of the PPP model. The effect of habitat quality and landscape configuration on the mortality and migration of prey were evaluated through the use of virtual habitats and landscapes. The findings suggested that a good habitat quality enables prey survival, increases the population available for predation by tigers. When a low-quality habitat is combined with a high-quality habitat, the number of migrating prey was high, reducing resources for tigers. This suggested that landscape composition should be considered when predicting population persistence of the Sumatran tiger. Optimal movement of two different prey resulted in a high density of prey in high-quality habitat, providing a concentration of prey in a tiger’s habitat, but resulted in a lower tiger predation rate than random movement and species specific movement. The PPP model has been applied to evaluate the effect of poaching, prey depletion, and their combination for the probability of extinction of a tiger population. The results from the evaluation showed that prey depletion, tiger poaching, and a combination of both, created a 100% probability of extinction within 20 years if the density and frequency of those threats at high rates. However, the duration of those threats in the system caused a 100% probability of extinction from tiger poaching. The results are able to contribute to optimize anti-poaching programs in future, to reduce significantly the probability of total extinction of Sumatran tiger. Furthermore, various landscape configurations have been tested against the probability and time of extinction for the Sumatran tiger population. The integration of spatial GIS-data in the model provides an insight into the relationship between tiger-prey-habitat. The results suggested that habitat quality surrounding a protected area plays an important role for the persistence of the Sumatran tiger population. This study also recommends agroforestry systems as reasonable land-use type in the vicinity of protected areas. They provide not only positive effects for tiger conservation purpose but they also appear as adaptable to the current land-use situation in Sumatra island. / Die vorliegende Dissertation beschreibt die Entwicklung des Panthera Populations Persistence (PPP) Modells, eines individuenbasierten Simulationsmodells für den Sumatra-Tiger (Panthera tigris sumatrae). Dieses stellt einen geeigneten theoretischen und anwendungsbezogenen Rahmen für den Schutz dieser Tiger-Unterart in Zentralsumatra bereit. Das PPP-Modell wurde entwickelt, um Einblicke in die Tiger-Beute-Habitat-Beziehungen zu gewinnen, sowie um den Effekt anthropogener Einflüsse auf den Fortbestand von Tigerpopulationen abzuschätzen. Dabei werden die drei Hauptprobleme für das Überleben des Sumatra-Tigers analysiert: die Wilderei, der Rückgang von Beutetieren und der Verlust von geeigneten Habitaten. Die Beschreibung des PPP-Modells gibt zunächst einen umfassenden Überblick zum aktuellen Wissensstand auf dem Gebiet des Tigerschutzes und integriert die wichtigsten Faktoren bereits existierender Modellansätze. Diese konnten durch die Einbeziehung einer detaillierten Beschreibung von individuellen Merkmalen und Verhalten verbessert werden. Das PPPModell stellt somit das Individuum in einen direkten Zusammenhang mit dessen Umwelt. Die Beziehung zwischen individuellem Verhalten, intrinsischen Merkmalen und externen Faktoren werden räumlich-explizit in einem bottom-up Ansatz simuliert. Damit kann sowohl die Populationsdynamik des Tigers als auch die seiner Beutetiere unter verschiedenen Annahmen beobachtet werden. Die Verknüpfung des PPP-Modells mit Geographischen Informationssystemen (GIS) bietet die Möglichkeit, die Reaktionsmechanismen der Individuen basierend auf der gegenwärtigen Landnutzungssituation zu simulieren und somit realitätsnahe räumliche Daten zu generieren. Die relative Bedeutung der Modell-Parameter auf die Simulationsergebnisse kann durch Sensitivitätsanalysen ermittelt werden. Hier wurden zwei verschiedene Ansätze verwendet: die Morris-Methode und die herkömmliche One-factor-at-a-time Methode. Der Vergleich beider methodischen Ansätze zeigte somit beispielhaft die Eignung unterschiedlicher Sensitivitätsanalysen für individuenbasierte Modelle auf. Die Morris-Methode zeigte, dass das Gesamtergebnis des PPP-Modells eine hohe Sensitivität gegenüber der Veränderung der Zeit aufweist, die ein Tigerweibchen braucht, um ihre Jungen aufzuziehen. Die Analyse zeigt auch, dass die Anzahl an abwandernden Tigern sensitiv gegenüber der IndividuellenWahrnehmungsdistanz von Beute ist. Der Vergleich mit einem ähnlichen Räuber-Beute-Modell lässt vermuten, dass diese Wahrnehmungsdistanz eines Individuums generell als ein entscheidender Faktor für Räuber-Beute-Beziehungen in räumlich-expliziten Individuenmodellen an- gesehen werden kann. Die Parametrisierung der IndividuellenWahrnehmungsdistanz des Tigers wurde so gewahlt, dass die damit ermittelten Simulationsergebnisse den Beutekonsum des Tigers, wie in der Literatur beschrieben, weitgehen widerspiegeln. Sie ist somit für die weitere Anwendung im PPP-Modell ausreichend gut beschrieben. Simulationsszenarien, welche verschiedene Habitatqualitäten sowie Landnutzungsmuster berücksichtigen, zeigen auch deren Bedeutung für die Mortalität und Migration der Beutetiere. Eine gute Habitatqualität hat eine geringe Mortalität der Beutetiere zur Folge, welche dann wiederum für den Tiger in ausreichender Zahl zur Verfügung stehen. Treten geringe Habitatqualitäten angrenzend an ein Habitat mit hoher Qualität auf, führte dies zu einer hohen Anzahl an abwandernden Beutetieren, womit sich die Ressourcen für den Tiger verringern. Die Landschaftsmerkmale sollten also bei der Vorhersage des Populationsfortbestandes des Sumatra-Tigers berücksichtigt werden. Die optimale Bewegung von zwei verschiedenen Beutetieren ergab eine hohe Beutedichte in einem Habitat mit hoher Qualität und stellte konzentriert Beute in einem Tigerhabitat bereit. Allerdings resultierte dies auch in einer geringeren Prädationsrate des Tigers, verglichen mit zufälligen oder artenspezifischen Bewegungen. Das PPP-Modell wurde angewandt, um die Auswirkungen von Wilderei, Beutetierrückgang sowie die Kombination beider Faktoren auf die Aussterbewahrscheinlichkeit einer Tigerpopulation zu bewerten. Die Ergebnisse zeigen, dass die genannten Faktoren eine 100-prozentige Aussterbewahrscheinlichkeit innerhalb von 20 Jahren zur Folge haben, wenn die Dichte und Häufigkeit dieser Bedrohungen hoch sind. Die Dauer dieser Bedrohungen im System verursachte allerdings eine 100-prozentige Aussterbewahrscheinlichkeit nur für die Wilderei von Tigern. Betrachtet man unabhängig von Dichte und Häufigkeit einzig die Dauer der Bedrohung, führt lediglich die Wilderei zum 100%-igen Aussterben. Diese Ergebnisse können maßgeblich dazu beitragen, zukünftig Schutzprogramme gegen die Wilderei zu optimieren, um das Aussterben des Sumatra-Tigers zu verhindern. DesWeiteren wurde der Einfluss von unterschiedlichen Landnutzungsmustern auf die Aussterbewahrscheinlichkeit und -zeit einer Sumatra-Tigerpopulation aufgezeigt. Die Integration von räumlichen GIS-Daten in das Modell ermöglichte einen Einblick in die Beziehungen zwischen Tiger, Beutetieren und Habitat. Die Ergebnisse zeigen, dass die Habitatqualität um Schutzgebiete herum eine wichtige Rolle für den Fortbestand der Population spielt. Die vorliegende Arbeit empfiehlt Agroforstsysteme als eine geeignete Landnutzungsform in der Nähe von Schutzgebieten, welche sowohl positive Effekte für den Tigerschutz bietet als auch mit den gegenwärtigen Landnutzungsmustern in Sumatra vereinbar erscheint.

Die Eutrophierung von Fließgewässern führt besonders im Frühjahr zur Zunahme der Biomasse des benthischen Aufwuchses. Dies kann zur reduzierter Infiltration von Wasser in die Gewässersohle führen und wichtige Funktionen von Fließgewässerökosystems stören. Verschiedene Studien konnten zeigen, dass invertebrate Weidegänger (Grazer) in der Lage sind die Biomasse des Aufwuchses in Fließgewässern effektiv zu reduzieren. Diese wichtige ökologische Funktion, das benthische Grazing, kann dazu beitragen negative Effekte der Eutrophierung in Fließgewässern zu kompensieren. Relevante invertebrate Grazer sind unter anderem die Larven der Eintagsfliege Rhithrogena semicolorata, die hohe Biomassen in Fließgewässern erreichen und eine hohe Spezialisierung auf Aufwuchs zeigen. Die Larven von R. semicolorata sind während ihres einjährigen Lebenszykluses Pestiziden ausgesetzt, welche ihre Entwicklung beeinträchtigen können. Um die Effekte von Pestiziden auf die Entwicklung dieser wichtigen Grazer zu untersuchen wurden drei Expositionsszenarien in Anlehnung an reale Bedingungen im Freiland untersucht. Das erste Szenario untersucht die Effekten einer Exposition mit dem Herbizid Terbutryn auf die Grazer-Aufwuchs-Interaktion, wie sie im Herbst und zeitigen Frühjahr anzutreffen ist. Terbutryn verursachte ab 6 µg/L eine deutliche Reduktion der Aufwuchsquantität, was indirekt das Wachstum und die Fettreserven der Grazer verringerte. Die Grazer zeigten ab 0,6 µg/L eine deutliche erhöhte Drift. Da bei dieser Konzentration noch keine Effekte auf die Aufwuchsbiomasse detektiert wurde, ist dies ein Indiz für verringerte Qualität des Aufwuchses. Insektzide werden verstärkt im Frühjahr ausgebracht und beeinflussen die Entwicklung der Grazer direkt. Das zweite Szenario untersuchte die Effekte des Insektizids lambda-Cyhalotrhin (LCH) auf die Grazer-Aufwuchs-Interaktion. LCH ist stark lipophil und adsorbiert schnell an organisches Material und Aufwüchse in Gewässer, weshalb es besonders für aufwuchsfressende Organismen bioverfügbar ist. Neben den erwarteten letalen Effekten wurden in Bereichen um 1 µg/g OC bereits subletale Effekte auf das Driftverhalten sowie das Wachstum der Grazer gefunden. Die Fettreserven waren ab ca. 0,01 µg/g OC reduziert, was auf verringerte Fraßaktivität in diesen niedrigen Konzentrationsbereichen schließen lässt. Die Analyse des Aufwuchses zeigte einen indirekt Effekt von LCH auf die Aufwuchsentwicklung, der einerseits auf die erhöhte Mortalität der Grazer aber auch auf LCH-induzierte Verhaltensänderungen zurückgeführt werden konnte. Das finale Szenario befasste sich mit den Effekten der kombinierten Exposition von Herbizid und Insektizid, wie sie im Lebenszyklus von R. semicolorata auftreten. Dabei zeigte sich entgegen der Erwartung keine erhöhte Mortalität durch die kombinierte Exposition. Die Ergebnisse weisen jedoch daraufhin, dass die Reduzierung der physiologischen Kondition der Grazer, durch die indirekten Effekte von Terbutryn, in subletalen Konzentrationsbereichen von LCH die Dauer bis zur Wiedererholung verlängert. Außerdem zeigte sich am Ende eine erhöhte Aufwuchsbiomasse, was eine reduzierte Leistung des Grazings durch die kombinierte Exposition indiziert. / The eutrophication of running water ecosystems leads especially in spring to an increase of benthic biofilms or aufwuchs, which reduces the infiltration of water into the river bed and, hence, disturb important ecological functions. Different studies already showed that invertebrate grazers of running water ecosystems are able to reduce the aufwuchs biomass effectively. This important ecological function, the benthic grazing, can therefore contribute to compensate the negative effects of eutrophication in lotic ecosystems. Relevant grazers are for instance the larvae of the mayfly Rhithrogena semicolorata, which reach high biomasses in streams and show a high feeding specialisation on aufwuchs. During their on year lasting life cycle the larvae of R. semicolorata are exposed to different pesticides, which can disturb their development. To evaluate the effects of pesticides on the development of this important grazer three exposition scenarios were performed following real exposure patterns from the environment. In the first scenarios the effects of a solely exposure with the herbicide Terbutryn on the grazer-aufwuchs-interaction was investigated, as it occurs preferably during autumn and spring. Terbutryn induced a clear reduction of aufwuchs quantity at 6 µg/L, which indirectly affected the growth and the energy storages of the grazers. Furthermore, the grazers showed an increased drift activity at 0.6 µg/L. Considering that the aufwuchs biomass was not affected at this low concentrations, the increased drift was interpreted as an indirect effect of reduced aufwuchs quantity. Inseciticides are preferably applied during spring and are able to disturb the development of grazers directly. The second scenario investigated therefore the effects of the insecticide lambda-Cyhalothrin (LCH) on the grazer-aufwuchs-interaction. LCH has a high lipophilicity and thus rapidly binds to organic matter or aufwuchs after entering aquatic ecosystems. This behaviour leads to a increased bioavailability of this substance to aufwuchs feeding organisms. Apart from the expected lethal effects, sublethal effects in form of increased drift and reduced grazer growth were found in a range of 1 µg/g OC LCH. Moreover, the energy storages of grazers were reduced at 0,01 µg/g OC, which is an indication of disturbed feeding behaviour at this low concentration. The analysis of the aufwuchs revealed additionally an indirect effect of LCH on the aufwuchs development, which was caused by increased grazer mortality and behavioural changes of the grazers induced by sublethal LCH concentrations. The final scenario aimed on the effects of a combined exposure of herbicide and insecticide, as it occurs during the life cycle of R. semicolorata. A increased mortality of grazers, due to the combinded exporsure, was not found. However, the results indicate that the reduction of the physiological condition by the indirect effect of Terbutryn extends the time until grazers recover from sublethal LCH exposure. Finally, also an increased aufwuchs biomass was found in treatments with combined exposure, indicating a reduced performance of grazers exposed to both substances.

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No description available.

Color removal of some reactive dyes (Blue 19, Black 5 and Red 195) using a local Poly Aluminium Chloride (PAC) was investigated with Jar-test experiment. The dyes were removed (above 94%) at optimal pH 7 (Red 195) and pH 10 (Blue 19 and Black 5). The PAC dosage of 220 mg/L (Blue 19 and Black 5) and 160 mg/L (Red 195) were found to be best for decreasing dye up to 50 mg/L (Black 5, Red 195) and 100 mg/L (Blue 19). Reaction time and agit ation speed also affected the decolorization process. That result indicates that Vietnamese PAC can be a robust and economical coagulant for discolorization of reactive dyeing process. / Chất keo tụ Poly Aluminium Chloride (PAC) sản xuất tại Việt nam được ứng dụng khử màu của một số màu nhuộm hoạt tính phổ biến (Blue 19, Black 5 and Red 195) trên thí nghiệm Jar-test. Kết quả cho thấy màu bị loại gần như hoàn toàn (trên 94 %) tại pH 7 (Red 195) hoặc 10 (Blue 19 và Black 5). Nồng độ PAC đạt hiệu quả tốt nhất tại 220 mg/L (Blue 19 và Black 5) và 160 mg/L (Red 195) ứng với nồng độ màu 50 mg/L (Black 5, Red 195) hay 100 mg/L (Blue 19). Thời gian phản ứng, tốc độ khuấy cũng có tác động đến hiệu suất khử màu. Kết quả nghiên cứu cho thấy PAC sản xuất tại Việt nam không những là một chất keo tụ tốt mà còn rất kinh tế cho việc khử màu hoàn toàn trong nước thải nhuộm hoạt tính.

In this study, the application of bipolar electrocoagulation (EC) with iron electrode has been assessed for color removal of simulated wastewater containing Reactive Red 195. The influence of initial pH, sodium sulfate concentration, initial dye concentration, electrolysis time, and electric current were examined. The optimum operational parameters were found to be pH =11, concentration of dye = 50 mg L-1, sodium sulfate concentration = 1200 mg L-1, electrolysis time = 5 min and electric current = 4 A. In such condition, color removal efficiency achieved over 99%. This result indicates that EC can be used as an efficient and “green” method for color removal from reactive dye solution. / Trong nghiên cứu này, quá trình khử màu nhuộm hoạt tính (Reactive Red 195) được khảo sát bằng hệ thống keo tụ điện hóa điện cực kép, với vật liệu sắt. Các yếu tố ảnh hưởng đến quá trình khử màu như pH, nồng độ màu nhuộm, nồng độ muối Na2SO4, thời gian phản ứng và cường độ dòng được lựa chọn nghiên cứu. Kết quả cho thấy hệ thống điện hóa trên loại gần như hoàn toàn màu nhuộm với hiệu suất đạt trên 99 % tại pH 11, nồng độ màu 50 mgL-1 và nống độ muối Na2SO4 1200 mgL-1 trong khoảng thời gian 5phút. Kết quả trên cho thấy keo tụ điện hóa có thể xem là một phương pháp xử lý hiệu quả và “xanh” trong việc loại bỏ hoàn toàn màu từ nước thải nhuộm hoạt tính.

This paper presents the result of dyeing solution coagulation with the use of ferrous ammonium sulfate hexah ydrate (FAS). The examined solution contains two reactive dyes: Black 5 and Blue 19. It has been shown that the efficiency of the dye removal depends on the type of dye, coagulation dosage and the initial pH. Our result showed that the increase of initial pH up to 12 enhanced the color removal efficiency; the FAS dose was 280 ml (Black 5) and 180 mg/l (Blue 19) at slow mixing time (15 min), agitation speed 60 rpm, and the initial dye concentration should be 50 and 100 mg/L for Black 5 and Blue 19, respectively. / Chất keo tụ sắt (II) amoni sulfate (FAS) được sử dụng khử màu của hai màu nhuộm hoạt tính phổbiến (Blue 19 và Black 5). Kết quả cho thấy, quá trình keo tụ bịảnh hưởng nhiều bởi loại màu nhuộm, nồng độ chất keo tụ và pH của dung dịch đầu vào. Với nồng độ FAS 280 mg/l (Black 5) và 180 mg/l (Blue 19), pH đầu vào dung dịch khoảng 12, thời gian phản ứng 15 phút, tốc độ khuấy 60 vòng/phút ứng với nồng độ màu Black 50 mg/L và blue 100 mg/L dung dịch gần như mất màu hoàn toàn.

Rice and maize are global staple food and play an important role in world’s food security strategy. Vietnam is one of rice leading export countries but annually it has to import a considerate amount of maize for cattle food processing. Red River Delta in the north of Vietnam is the second rice bucket of the country, which is responsible formore than 20% of total rice production. The priority crops in the areas are rice and maize and rice-maize system is the leading cropping system in the area. Currently, it is reported that the rice-maize cropping system is not sustainable and its profit is reducing in most of production areas in the Red River Delta. Improving rice cropping system aims is not only to increase rice and maize yields and production but also to improve the land use efficiency, decline the cost of the production and to increase system sustainability. To increase sustainability there must be a linkage of various factors. This review emphasizes on increasing rice-maize crop sustainability by applying appropriate agriculture practices such as reducing chemical fertilization and intensive tillage. / Gạo và ngô là nguồn lương thực chính cho toàn cầu và đóng một vai trò quan trọng trong chiến lược an ninh lương thực của thế giới. Việt Nam là một trong những nước dẫn đầu về xuất khẩu gạo nhưng hàng năm vẫn phải nhập một số lượng lớn ngô để chế biến thức ăn gia súc. Đồng bằng sông Hồng là một trong hai vựa lúa lớn của Việt Nam sản xuất khoảng 20% sản lượng lúa gạo của cả nước. Ở đồng bằng sông Hồng, lúa và ngô là hai cây trồng chính là hệ canh tác lúa-ngô là cơ cấu cây trồng hàng đầu trong vùng. Tuy nhiên, trong những năm gần đây, rất nhiều đánh giá cho thấy hệ thống canh tác lúa-ngô là hệ thống canh tác không bền vững và các lợi nhuận của mang lại từ cơ cấu canh tác ở hầu hết các khu vực sản xuất ở vùng đồng bằng sông Hồng của Việt Nam đã và đang giảm dần. Do đó, việc cải thiện cơ cấu canh tác lúa-ngô không chỉ nhằm mục đích tăng năng suất lúa và ngô mà còn nâng cao hiệu quả sử dụng đất, giảm chi phí sản xuất và tăng cường hệ thống canh tác bền vững. Tuy nhiên, để tăng tính bền vững của hệ thống canh tác thì phải liên kết nhiều yếu tố khác nhau. Bài viết này dựa vào các kết quả nghiên cứu của các tác giả khác nhau để đưa ra những giải pháp tích cực làm tăng tính bền vững của hệ thống canh tác lúa-ngô bằng cách áp dụng các phương pháp canh tác hợp lý như giảm sử dụng phân hóa học và các biện pháp canh tác thâm canh như áp dụng phương pháp làm đất tối thiểu.

Die Broschüre gibt einen Überblick über die Ergebnisse des EU-Projektes TransGeoTherm. Im Projekt wurde ein grenzüberschreitendes 3D-Modell entwickelt, das den geologischen Untergrund der Neiße-Region darstellt. Mit dem 3D-Modell wurden geothermische Potenzialkarten berechnet. Damit steht erstmals für diese Region ein Hilfsmittel für die qualifizierte Planung geothermischer Anlagen zur Verfügung. Der Abschlussbericht richtet sich an Bürger, Unternehmen, Behörden und Institutionen, die sich mit der Erdwärmenutzung befassen.

No description available.