401 research outputs found

    Jatropha curcas L.: Visions and Realities

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    Since several years Jatropha is experiencing a renaissance. The main drivers for this development are the biofuel boom in general and the special attributes of Jatropha itself. This paper discusses the current knowledge as well as expectations of Jatropha and the consequential outcomes starting with data availability and quality followed by economic and political needs and constraints

    Opportunities and constraints for agrofuels in developing countries : case studies on economic viability and employment effects of Jatropha production

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    This dissertation was motivated by controversial statements of politicians and lobby groups for and against first-generation agrofuel production. Therefore this thesis contributes to a more realistic view on opportunities and constraints for agrofuel production based on first-generation technologies. The findings are based on an intensive literature review covering the following topics: current production trends of ethanol and agrodiesel, their potential for fossil energy substitution and greenhouse gas reduction including related costs, rural development and poverty alleviation. This more general overview on agrofuels was deepened by own research on Jatropha seed production in India and Madagascar. In this context the economic viability of Jatropha seed production and possible income effects for households living in the vicinity of a Jatropha plantation were analyzed. For this special agrofuel feedstock the findings allowed shedding some light on important aspects of the much broader topic concerning the production of agrofuels. To cover the above mentioned topics this dissertation is structured around three research papers. The first paper identifies and discusses the opportunities and constraints of first-generation agrofuel production in developed and developing countries and is based on an intensive literature review. Therefore this paper contrasts arguments used by politicians to justify agrofuel support measures like energy security, greenhouse gas reduction potential, income generation and possible rural development with new scientific findings on each argument. Furthermore data on worldwide trends in ethanol and agrodiesel production were presented. The second paper focuses on one possible option to lower competition between food and agrofuel production at least partially. This option is seen in the production of Jatropha seeds on marginal land not suitable for food production. In this context an Indian case study revealed the economic viability of Jatropha seed production on marginal land. The database for this study includes data derived from literature as well as experimental field data provided by the ?International Crops Research Institute for the Semi-Arid Tropics?. The third paper addresses possible income effects for rural households offering their labour force to a Jatropha plantation in central Madagascar. The econometric impact assessment is based on a socio-economic household survey undertaken by the author in 2009. To account for possible selection bias the propensity score matching approach was used to estimate the average treatment effect on the treated by comparing the average income of Jatropha plantation households and control households. The findings for 336 households reveal positive income effects for households working at the Jatropha plantation. The dissertation concludes that more investments in research are needed to gain a potential win-win situation for rural households, investors and the environment especially for the case of developing countries. The results lead to the conclusion, that smallholder based Jatropha seed production should not be promoted in developing countries. Therefore this dissertation concludes further that it would be far better for developing countries to let international investors set up Jatropha plantations, hence in this case the economic risk is borne by the foreign investors. Furthermore abundant labour in rural areas could find employment opportunities with such plantations and therefore would be able to generate some income for their families. Nevertheless the implementation of Jatropha projects financed by international investor?s needs regulations set up by national governments. Those regulations should cover each aspect within the entire value chain of Jatropha agrofuel production and should be embedded in a national energy and rural development policy. Furthermore institutional frameworks such as land tenure security and labour rights have to be enforced. Setting up aforementioned regulations and institutional frameworks can prevent possible constraints such as, land grabbing, exploitation of rural labourers, loss of biodiversity and competition between Jatropha seed and food production e.g. for scarce water, which could occur due to foreign investment in local Jatropha (and other agrofuel feedstocks) cultivation in the worst case.Diese Dissertation wurde durch die kontroversen Äußerungen von Politikern und Lobbyisten über das Für und Wider von Agrartreibstoffen der ersten Generation motiviert. Ziel dieser Arbeit war es basierend auf einer Durchsicht relevanter Literatur einerseits die weltweite Produktion von Ethanol und Agrardiesel anhand von Produktionszahlen aufzuzeigen und andererseits zur Beantwortung der folgenden Fragen beizutragen. Inwieweit kann die Produktion von Agrartreibstoffen der ersten Generation zum einen eine Strategie darstellen, die die Abhängigkeit von fossilen Treibstoffen reduziert und damit den Ausstoß an Treibhausgasen vermindert, einschließlich der damit verbundenen Kosten? Welche Möglichkeiten bestehen, dass die Produktion von Rohstoffen für die Agrartreibstoff-herstellung zur Entwicklung ländlicher Räume und damit zur Armutsminderung beiträgt? Diese eher generelle Übersicht zur Produktion von Agartreibstoffen der ersten Generation wurde vertieft durch eigene Forschung hinsichtlich der Produktion von Jatrophasamen in Indien und Madagaskar. In diesem Zusammenhang wurde analysiert ob die Produktion von Jatrophasamen mit dem Ziel einen wettbewerbsfähigen Agrartreibstoff herzustellen wirtschaftlich betrieben werden kann und welche Einkommenseffekte durch eine Jatrophaplantage für Haushalte in deren Umgebung entstehen können. Die erzielten Ergebnisse erlauben es einen kleinen jedoch wichtigen Aspekt für ein mögliches Rohmaterial der Agrartreibstoffherstellung innerhalb des großen Rahmens der Agrartreibstoffproduktion besser zu verstehen. Diese Dissertation gliedert sich in drei wissenschaftliche Artikel. Der erste Artikel identifiziert und diskutiert Möglichkeiten und Beschränkungen, denen die Agrartreibstoffproduktion mit Technologien der ersten Generation in Industrienationen und Entwicklungsländern unterliegt anhand einer intensiven Literaturdurchsicht. Diesbezüglich setzt er sich mit den durch Politiker angeführten Argumenten Energiesicherheit, Treibhausgasreduktion, Generierung zusätzlicher Einkommensmöglichkeiten und ländliche Entwicklung auseinander, da diese die Basis für gewährte politische Unterstützung der Agrartreibstoffproduktion darstellen. Weiter wird die Entwicklung der weltweiten Ethanol- und Agrardieselproduktion aufgezeigt. Der Möglichkeit einen Rohstoff für die Agrartreibstoffherstellung auf marginalen Standorten zu produzieren und somit die Konkurrenz zur Nahrungsmittelproduktion zu verringern widmet sich der zweite Artikel. Hierbei wurde in einer Fallstudie die Wirtschaftlichkeit der Produktion von Jatrophasamen auf solchen Standorten am Beispiel Indiens analysiert. Diese Analyse stützt sich auf Sekundärdaten relevanter Literatur und kombiniert diese mit neuen Ergebnissen basierend auf Feldexperimenten durch das ?International Crops Research Institute for the Semi-Arid Tropics?. Der dritte Artikel beschäftigt sich mit der Berechnung von Einkommenseffekten für Haushalte, die auf einer Jatrophaplantage in Zentralmadagaskar arbeiten. Dazu wurde eine ökonometrische Analyse basierend auf den Daten einer sozioökonomischen Haushaltsbefragung durchgeführt. Die Erhebung der verwendeten Daten erfolgte durch den Autor im Frühjahr 2009. Um mögliche Selektionseffekte der Haushalte zu berücksichtigen wurde die Methodik des ?Propensity Score Matching? angewendet. Diese Methodik erlaubte es Haushalte, die auf der Jatrophaplantage arbeiten, mit ähnlichen Haushalten einer Kontrollgruppe hinsichtlich ihres Einkommens zu vergleichen. Anhand einer Stichprobe von 336 Haushalten konnten positive Einkommenseffekte für Plantagenhaushalte nachgewiesen werden. Weiterhin führen die Ergebnisse dieser Arbeit zu dem Schluss, dass zum gegenwärtigen Zeitpunkt der kleinbäuerliche Anbau von Jatropha in Entwicklungsländern nicht forciert werden sollte. Aufgrund dessen sollten Entwicklungsländer vorerst internationale Investoren mit der Etablierung von Jatrophaplantagen betrauen, da diese fähig sind die ökonomischen Risiken eher zu tragen als lokale Kleinbauern. Dieser Fall kann zu einer Belebung des ländlichen Arbeitsmarktes führen, und ungelernten Arbeitskräften und ihren Familien Einkommensalternative bieten. Regierungen sollten jedoch die Aktivitäten ausländischer Investitionen durch das Entwickeln gesetzlicher und institutioneller Rahmenbedingungen für eine nationale Produktion von Agrartreibstoffen begleiten. Besonders anzuraten ist die Einbindung einer möglichen Jatrophatreibstoffproduktion und ihrer einzelnen Produktionsschritte in einen nationalen Energie- und Entwicklungsplan. Weiter sollten Anstrengung zur Sicherung von Landbesitz und gegen eine mögliche Ausbeutung von Plantagenarbeitern auf nationaler Ebene unternommen werden. Durch diese gesetzlichen und institutionellen Rahmenbedingung können negative Auswirkungen, von Auslandsinvestitionen in Jatrophaproduktion (sowie in andere Rohstoffe für die Gewinnung von Agrartreibstoffen), wie Landraub, die Ausbeutung von Plantagenarbeitern, Biodiversitätsverluste und eine mögliche Konkurrenz zwischen Jatropha und Nahrungsmittelproduktion z.B. um knappe Wasserressourcen verringert bzw. vermieden werden

    Clara Zetkin und Stockholm 1917

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    Non-destructive Three-dimensional Imaging of Artificially Degraded CdS Paints by Pump-probe Microscopy

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    Cadmium sulfide (CdS) pigments have degraded in several well-known paintings, but the mechanisms of degradation have yet to be fully understood. Traditional non-destructive analysis techniques primarily focus on macroscopic degradation, whereas microscopic information is typically obtained with invasive techniques that require sample removal. Here, we demonstrate the use of pump-probe microscopy to nondestructively visualize the three-dimensional structure and degradation progress of CdS pigments in oil paints. CdS pigments, reproduced following historical synthesis methods, were artificially aged by exposure to high relative humidity (RH) and ultraviolet (UV) light. Pump-probe microscopy was applied to track the degradation progress in single grains, and volumetric imaging revealed early CdS degradation of small particles and on the surface of large particles. This indicates that the particle dimension influences the extent and evolution of degradation of historical CdS. In addition, the pump-probe signal decrease in degraded CdS is observable before visible changes to the eye, demonstrating that pump-probe microscopy is a promising tool to detect early-stage degradation in artworks. The observed degradation by pump-probe microscopy occurred through the conversion from CdS into CdSO4.xH2O, verified by both FTIR (Fourier-transform infrared) and XPS (X-ray photoelectron spectroscopy) experiment

    Correlation of Incisura Anatomy With Syndesmotic Malreduction

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    Background: The anatomy of the syndesmosis is variable, yet little is known on the correlation between differences in anatomy and syndesmosis reduction results. The aim of this study was to analyze the correlation between syndesmotic anatomy and the modes of syndesmotic malreduction. Methods: Bilateral postreduction ankle computed tomography (CT) scans of 72 patients treated for fractures with syndesmotic disruption were analyzed. Incisura depth, fibular engagement into the incisura, and incisura rotation were correlated with degree of syndesmotic malreduction in coronal and sagittal planes as well as rotational malreduction. Results: Clinically relevant malreduction in the coronal plane, sagittal plane, and rotation affected 8.3%, 27.8%, and 19.4% of syndesmoses, respectively. The syndesmoses with a deep incisura and the fibula not engaged into the tibial incisura were at risk of overcompression, anteverted incisuras at risk of anterior fibular translation, and retroverted incisuras at risk of posterior fibular translation. Conclusions: Certain morphologic configurations of the tibial incisura increased the risk of specific syndesmotic malreduction patterns. Level of Evidence: Level III, comparative study

    Pain perception after colorectal surgery: A propensity score matched prospective cohort study.

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    The purpose of this prospective cohort study was to compare multimodal pain management and pain perception after open vs. laparoscopic colorectal surgery within enhanced recovery care. Pain scores at rest and at mobilization were prospectively assessed in consecutive patients using Visual Analog Scales (VAS 0-10) and consumption of different analgesics was recorded daily until 96 hours postoperatively. Uni- and multivariate risk factors for pain peaks (≥ 4/10) were identified by logistic regression and compared between two propensity score matched groups (open vs. laparoscopic). 156 open and 176 laparoscopic procedures were included. Mean VAS scores were consistently < 3 until 96 hours at rest and at mobilization. Patients operated by laparoscopy experienced more pain peaks (≥ 4) within 24 hours (p < 0.05), while patients operated by open approach experienced more pain peaks (≥ 4) during mobilization at 72 hours (p < 0.05). Independent risk factors for insufficient pain control (≥ 4) within 24 hours from surgery were duration of the procedure (OR 3.37, 95%CI 2.03-5.59), emergency surgery (OR 3.01, 95%CI 1.72-5.31), wound infiltration (OR 3.23, 95%CI 0.97-10.70), age < 70 years (OR 2.03, 95% CI 1.18-3.48) and ASA I-II score (OR 2.06, 95% CI 1.19-3.56). The perioperative adding of lidocaine ± ketamine to opioids did not improve postoperative pain perception nor decrease morphine equivalents. In conclusion, overall pain scores were low after colorectal surgery. However, pain peaks remained a concern early after minimally invasive surgery and after epidural removal for open surgery. Multimodal strategies were not superior to opioids alone

    Preoperative Nutritional Conditioning of Crohn's Patients-Systematic Review of Current Evidence and Practice.

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    Crohn's disease is an incurable and frequently progressive entity with major impact on affected patients. Up to half of patients require surgery in the first 10 years after diagnosis and over 75% of operated patients require at least one further surgery within lifetime. In order to minimize surgical risk, modifiable risk factors such as nutritional status need to be optimized. This systematic review on preoperative nutritional support in adult Crohn's patients between 1997 and 2017 aimed to provide an overview on target populations, screening modalities, routes of administration, and expected benefits. Pertinent study characteristics (prospective vs. retrospective, sample size, control group, limitations) were defined a priori. Twenty-nine studies were retained, of which 14 original studies (9 retrospective, 4 prospective, and 1 randomized controlled trial) and 15 reviews. Study heterogeneity was high regarding nutritional regimens and outcome, and meta-analysis could not be performed. Most studies were conducted without matched control group and thus provide modest level of evidence. Consistently, malnutrition was found to be a major risk factor for postoperative complications, and both enteral and parenteral routes were efficient in decreasing postoperative morbidity. Current guidelines for nutrition in general surgery apply also to Crohn's patients. The route of administration should be chosen according to disease presentation and patients' condition. Further studies are needed to strengthen the evidence

    Lethal Carbon Monoxide Poisoning in Wood Pellet Storerooms—Two Cases and a Review of the Literature

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    The installation of wood pellet heating as a cost-effective and climatically neutral source of energy for private households has increased steadily in recent years. We report two deaths that occurred within the space of about a year in wood pellet storerooms of private households in German-speaking countries and were investigated by forensic medical teams. This is the first report of fatalities in this special context as is shown in the literature review. Both victims died of carbon monoxide (CO) poisoning; one of the victims was a woman who was 4 months pregnant. Measurements at the scene detected life-threatening CO concentrations (7500 ppm, >500 ppm), which were not significantly reduced after ventilation of the storerooms as required by regulations. We carried out a series of experiments in order to confirm CO production by wood pellets. Thirty kilograms of freshly produced pellets from two different manufacturers were stored for 16 days in airtight containers at 26°C with different relative humidities. CO concentrations between 3100 and 4700 ppm were measured in all containers. There were no notable differences between the wood pellet products or storage at different humidities. Emission of CO from wood pellets has already been described, but fatal accidents have previously been reported only in association with pellet transport on cargo ships or storage in silos. It is therefore a new finding that fatal accidents may also occur in the wood pellet storerooms of private households. We show that significant CO concentrations can build up even when these rooms are ventilated in accordance with the regulations and that such levels may cause the death of healthy persons, as described in the following. As the safety recommendations from the wood pellet industry are inadequate, we consider that further fatal accidents are likely to occur and recommend urgent revision of the safety regulation

    Perioperative Nutrition in Abdominal Surgery: Recommendations and Reality

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    Introduction. Preoperative malnutrition is a major risk factor for increased postoperative morbidity and mortality. Definition and diagnosis of malnutrition and its treatment is still subject for controversy. Furthermore, practical implementation of nutrition-related guidelines is unknown. Methods. A review of the available literature and of current guidelines on perioperative nutrition was conducted. We focused on nutritional screening and perioperative nutrition in patients undergoing digestive surgery, and we assessed translation of recent guidelines in clinical practice. Results and Conclusions. Malnutrition is a well-recognized risk factor for poor postoperative outcome. The prevalence of malnutrition depends largely on its definition; about 40% of patients undergoing major surgery fulfil current diagnostic criteria of being at nutritional risk. The Nutritional Risk Score is a pragmatic and validated tool to identify patients who should benefit from nutritional support. Adequate nutritional intervention entails reduced (infectious) complications, hospital stay, and costs. Preoperative oral supplementation of a minimum of five days is preferable; depending on the patient and the type of surgery, immune-enhancing formulas are recommended. However, surgeons' compliance with evidence-based guidelines remains poor and efforts are necessary to implement routine nutritional screening and nutritional support
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