1,439 research outputs found

    Weather Derivatives as an Instrument to Hedge Against the Risk of High Energy Cost in Greenhouse Production

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    In many areas agriculture is exposed to weather related risks. Weather derivatives that get more and more in the focus of interest can reduce these risks. In this study we develop a temperature based weather derivative and analyse how it can reduce the weather-related energy cost risk in greenhouse production. We base this study on a temperature index whose stochastic characteristics are analysed. Finally we simulate the heating demand for energy of a horticultural firm.Environmental Economics and Policy, Risk and Uncertainty, C22, D8, Q14,

    Wetterderivate als Instrument im Risikomanagement landwirtschaftlicher Betriebe

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    Die vergangenen und vermutlich zukünftigen Reformen der gemeinsamen Agrarpolitik führen bei landwirtschaftlichen Aktivitäten zu einem Anstieg der Risiken. Marktrisiken nehmen durch Marktliberalisierungen und daraus resultierenden abnehmenden Preisstützungen zu. Darüber hinaus können strengere Richtlinien bei der Anwendung von Pflanzenschutzmitteln die Ertragsvariabilität erhöhen. Daher erscheint es sinnvoll, neue oder zusätzliche Instrumente des Risikomanagements zu analysieren. In diesem Kontext stellen Wetterderivate ein neues Konzept dar, das in jüngster Vergangenheit zunehmend Interesse auf sich gezogen hat. Im Gegensatz zu klassischen Finanzderivaten wird bei solchen die Auszahlung von zukünftigen Wettereignissen wie Temperatur oder Niederschlag determiniert. Dadurch ist die Absicherung von Risiken möglich, die nicht aus der Wertänderung von gehandelten Finanztiteln sondern aus der Unsicherheit zukünftiger klimatischer Prozesse stammen. Ziel der vorliegenden Arbeit ist die einzelbetriebliche Wirkungsanalyse von Wetterderivaten, wobei drei verschiedene Modelle genutzt werden. Es sollen Möglichkeiten und Grenzen von Wetterderivaten als Instrument im Risikomanagement in landwirtschaftlichen Betrieben aufgezeigt werden. Die Arbeit beginnt mit einer Darstellung von Risiko und Risikomanagement, wobei verschiedene Methoden der Risikobeurteilung diskutiert werden. Risiko wird häufig mit Lower Partial Moments gemessen, bei denen keine Annahme der exakten Verteilung der Zufallsvariable vorausgesetzt werden muss. Im Gegensatz zu Versicherungen ist bei Wetterderivaten keine adverse Selektion oder moral hazard möglich. Jedoch zeigt eine Korrelationsanalyse zwischen den Wetterparametern Temperatur und Niederschlag und dem Ertrag von verschiedenen Kulturen an verschiedenen Kulturen keine einheitlichen Beziehungen den Parametern. In der vorliegenden Arbeit werden ein autoregressiver Prozess dritter Ordnung für die Modellierung der Temperaturentwicklung und ein Markovkettenmodell für die Niederschlagsentwicklung verwendet. Ein Gewächshausmodellbetrieb wird entwickelt, um den Einfluss eines Temperaturderivats auf das Heizenergiekostenrisiko zu überprüfen. In zwei weiteren Modellen wird der Einfluss von Niederschlagsderivaten auf das Ertragsrisiko von Stärkekartoffeln und Zwiebeln analysiert. Das Zwiebelmodell wird einer gesamtbetrieblichen Wirkungsanalyse unterzogen. Eine Risikoreduzierung der mit dem Wetterderivat abgesicherten Kultur wird erzielt, wobei sich der Effekt im diversifizierten Modellbetrieb auf gesamtbetrieblicher Ebene verringert.Weather Derivatives as Risk Management Tool in Agriculture Past and presumable future reforms of the CAP tend to increase the risk associated with farming activities. Globalisation of trade combined with declining commodity price support result in an increase of market risks. Besides this, more stringent regulations with respect to the application of agro chemicals cause an increase of yield variability. It therefore appears worthwile analysing new or additional risk management instruments. Among these are weather derivatives a fairly new concept that has recently gained a considerable amount of interest. Contrary to traditional financial derivatives their payoff is determined by future weather events such as temperature or precipitation. Thus, they allow the securitisation of risks which are not caused by changes of market value of traded finance titles but result from the uncertainty of the climatic processes. The study addresses the farm level impacts of hedging with weather derivatives using three modelling approaches. The objective is to evaluate the economic attractiveness of weather derivatives and to assess their potential and limitations as farm level instruments of risk management. The study starts with a description of risk and risk management whereby different methods of risk assessment are discussed. Risk exposure is often presented by Lower Partial Moments who do not need an exact distribution assumption of the random variable. Contrary to insurances weather derivatives do not evoke adverse selection and moral hazard. However, in this study correlation analysis between temperature, precipitation and yield of different crops on different sites show no standardised relation between these parameters. The development of weather parameters can be modelled in different ways. In this study a third order autoregressive process is used for temperature and in case of precipitation a Markov Chain model. To review the impact of a temperature derivative on the heating energy cost risk a greenhouse model firm is used. Precipitation derivatives are modelled to analyse their impact on the yield risk of starch potatoes and onions. The latter is used to evaluate the whole-farm effect of weather derivatives. A risk reduction for the hedged crop is achieved by using the weather derivative. In the diversified model farm on whole farm level the risk reducing effect diminishes

    Fostering Self-Regulated Learning in Online Environments: Positive Effects of a Web-Based Training With Peer Feedback on Learning Behavior

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    Although training in self-regulated learning (SRL) is effective in improving performance, human trainers can reach only a few people at a time. We developed a web-based training for potentially unlimited numbers of participants based on the process model of SRL by Schmitz and Wiese (2006). A prior study (Bellhäuser et al., 2016) observed positive effects on self-reported SRL and self-efficacy. In the present randomized controlled trial, we investigated an improved version of the web-based training, augmented by the application of peer feedback groups. Prospective university students in an online mathematics preparation course were assigned randomly to one of four experimental conditions: Group D (diary), group TD (training + diary), group TDP (training + diary + peer feedback group), and group C (control). Complete data was obtained for 136 participants (78.8% male; M = 19.8 years). The learning diary was intended to trigger goal setting, planning, and self-motivation in the morning and reflection in the evening. The web-based training consisted of three lessons (approximately 90 min each) with videos, presentations, self-tests, and exercises. In the peer feedback condition, participants were randomly assigned to groups of five persons each and used a bulletin board to discuss pre-defined topics related to the content of the web-based training. Outcome measures included a test of declarative SRL knowledge, an SRL questionnaire, a general self-efficacy scale, log file data, and a mathematics test. Results showed positive effects for the web-based training, particularly when combined with peer feedback on both SRL knowledge and SRL questionnaires, self-efficacy, and on objective time-investment, but not on the mathematics test. The learning diary did not exhibit positive effects. We conclude that additional peer-feedback seems to be a useful supplement to web-based trainings with comparably low organizational costs

    The Role of Motivational Regulation in Exam Preparation: Results From a Standardized Diary Study

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    Previous studies have shown that the use of motivational regulation strategies has the potential to sustain invested effort and persistence in the learning process. Combining different methods (questionnaires and standardized diaries), the present study aimed to determine the role of motivational regulation in an exam preparation period. Motivational regulation is differentiated in a quantitative (extent of strategy use) and a qualitative (planning, implementing, monitoring, and correcting strategy use) aspect. One hundred and fifteen university students reported the quantity and quality of their motivational regulation strategy use in a pretest and kept a standardized learning diary focused on motivational difficulties and invested effort over a 14-day period just before an exam in their studies. Exam performance was assessed afterward. Results revealed positive effects of both aspects of motivational regulation on invested effort in exam preparation and exam performance. Moreover, a high quality of motivational regulation was associated with reduced negative effects of motivational difficulties on invested effort during studying—implying that motivational regulation can buffer against specific motivational problems occurring in the learning process

    From a Biomarker to Targeting in a Proof-Of-Concept Trial

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    Background There is high medical need for safe long-term immunosuppression monotherapy in kidney transplantation. Selective targeting of post-transplant alloantigen-(re)activated effector-T cells by anti-TNF antibodies after global T cell depletion may allow safe drug minimization, however, it is unsolved what might be the best maintenance monotherapy. Methods In this open, prospective observational single-centre trial, 20 primary deceased donor kidney transplant recipients received 2x20 mg Alemtuzumab (d0/d1) followed by 5 mg/kg Infliximab (d2). For 14 days all patients received only tacrolimus, then they were allocated to either receive tacrolimus (TAC, n = 13) or sirolimus (SIR, n = 7) monotherapy, respectively. Protocol biopsies and extensive immune monitoring were performed and patients were followed-up for 60 months. Results TAC-monotherapy resulted in excellent graft survival (5yr 92%, 95%CI: 56.6–98.9) and function, normal histology, and no proteinuria. Immune monitoring revealed low intragraft inflammation (urinary IP-10) and hints for the development of operational tolerance signature in the TAC- but not SIR-group. Remarkably, the TAC-monotherapy was successful in all five presensitized (ELISPOT+) patients. However, recruitment into SIR-arm was stopped (after n = 7) because of high incidence of proteinuria and acute/chronic rejection in biopsies. No opportunistic infections occurred during follow-up. Conclusions In conclusion, our novel fast-track TAC- monotherapy protocol is likely to be safe and preliminary results indicated an excellent 5-year outcome, however, a full–scale study will be needed to confirm our findings. Trial Registration EudraCT Number: 2006-003110-1

    Многокомпонентные термины сферы автомобилестроения: структура и способы перевода с английского языка на русский

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    Работа нацелена на выявление структурных особенностей многокомпонентных терминов сферы автомобилестроения и особенностей их перевода с английского языка на русский. В результате исследования были выявлены формально-структурные модели английских многокомпонентных терминов, определены основные ядерные термины, участвующие в процессе терминодеривации. Были выявлены основные способы перевода многокомпонентных терминов с английского языка на русский язык, сделаны выводы об особенностях перевода многокомпонентных терминов в зависимости от их формально-структурных моделей.The thesis is aimed at revealing the structural features of multi-component terms of the automotive industry and the features of their translation from English into Russian. Research resulrs: formal structural models of English multicomponent terms have been identified, the most representative nuclear terms participating in the term-derivation process have been identified.The most efficient ways of translation of multi-component terms from English into Russian have been identified, the relation between the way multi-component terms were translated and its formal structure have been traced

    Mode of action-based risk assessment of genotoxic carcinogens

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    The risk assessment of chemical carcinogens is one major task in toxicology. Even though exposure has been mitigated effectively during the last decades, low levels of carcinogenic substances in food and at the workplace are still present and often not completely avoidable. The distinction between genotoxic and non-genotoxic carcinogens has traditionally been regarded as particularly relevant for risk assessment, with the assumption of the existence of no-effect concentrations (threshold levels) in case of the latter group. In contrast, genotoxic carcinogens, their metabolic precursors and DNA reactive metabolites are considered to represent risk factors at all concentrations since even one or a few DNA lesions may in principle result in mutations and, thus, increase tumour risk. Within the current document, an updated risk evaluation for genotoxic carcinogens is proposed, based on mechanistic knowledge regarding the substance (group) under investigation, and taking into account recent improvements in analytical techniques used to quantify DNA lesions and mutations as well as “omics” approaches. Furthermore, wherever possible and appropriate, special attention is given to the integration of background levels of the same or comparable DNA lesions. Within part A, fundamental considerations highlight the terms hazard and risk with respect to DNA reactivity of genotoxic agents, as compared to non-genotoxic agents. Also, current methodologies used in genetic toxicology as well as in dosimetry of exposure are described. Special focus is given on the elucidation of modes of action (MOA) and on the relation between DNA damage and cancer risk. Part B addresses specific examples of genotoxic carcinogens, including those humans are exposed to exogenously and endogenously, such as formaldehyde, acetaldehyde and the corresponding alcohols as well as some alkylating agents, ethylene oxide, and acrylamide, but also examples resulting from exogenous sources like aflatoxin B1_{1}, allylalkoxybenzenes, 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), benzo[a]pyrene and pyrrolizidine alkaloids. Additionally, special attention is given to some carcinogenic metal compounds, which are considered indirect genotoxins, by accelerating mutagenicity via interactions with the cellular response to DNA damage even at low exposure conditions. Part C finally encompasses conclusions and perspectives, suggesting a refined strategy for the assessment of the carcinogenic risk associated with an exposure to genotoxic compounds and addressing research needs
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