992 resultados para cation exchange capacity (CEC)
Resumo:
An important policy issue in recent years concerns the number of people claimingdisability benefits for reasons of incapacity for work. We distinguish between workdisability , which may have its roots in economic and social circumstances, and healthdisability which arises from clear diagnosed medical conditions. Although there is a linkbetween work and health disability, economic conditions, and in particular the businesscycle and variations in the risk of unemployment over time and across localities, mayplay an important part in explaining both the stock of disability benefit claimants andinflows to and outflow from that stock. We employ a variety of cross?country andcountry?specific household panel data sets, as well as administrative data, to testwhether disability benefit claims rise when unemployment is higher, and also toinvestigate the impact of unemployment rates on flows on and off the benefit rolls. Wefind strong evidence that local variations in unemployment have an importantexplanatory role for disability benefit receipt, with higher total enrolments, loweroutflows from rolls and, often, higher inflows into disability rolls in regions and periodsof above?average unemployment. Although general subjective measures of selfreporteddisability and longstanding illness are also positively associated withunemployment rates, inclusion of self?reported health measures does not eliminate thestatistical relationship between unemployment rates and disability benefit receipt;indeed including general measures of health often strengthens that underlyingrelationship. Intriguingly, we also find some evidence from the United Kingdom and theUnited States that the prevalence of self?reported objective specific indicators ofdisability are often pro?cyclical that is, the incidence of specific forms of disability arepro?cyclical whereas claims for disability benefits given specific health conditions arecounter?cyclical. Overall, the analysis suggests that, for a range of countries and datasets, levels of claims for disability benefits are not simply related to changes in theincidence of health disability in the population and are strongly influenced by prevailingeconomic conditions. We discuss the policy implications of these various findings.
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It was studied the parasitism capacity of Trichogramma acacioi on Anagasta kuehniella and Sitotroga cerealella eggs at different temperatures (15, 20, 25, 30 and 35 ± 1°C). The parasitism of T. acacioi varied with temperature and host. The highest parasitism (³80%) were observed during the first days after emergence in both hosts, at all tested temperatures. The accumulated parasitism varied with both host and temperature, being higher on A. kuehniella at 20°C, what shows good parasitoid species adaptation to this temperature. Thus, we conclude that the best host and best temperature to be used at mass-rearing of T. acacioi is A. kuehniella and 20ºC, respectively. Moreover, this Trichogramma species has great potential to be used in field releases at regions where average temperature is around 20ºC.
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Considerable experimental evidence suggests that non-pecuniary motivesmust be addressed when modeling behavior in economic contexts. Recentmodels of non-pecuniary motives can be classified as either altruism-based, equity-based, or reciprocity-based. We estimate and compareleading approaches in these categories, using experimental data. Wethen offer a flexible approach that nests the above three approaches,thereby allowing for nested hypothesis testing and for determiningthe relative strength of each of the competing theories. In addition,the encompassing approach provides a functional form for utility in different settings without the restrictive nature of the approaches nested within it. Using this flexible form for nested tests, we findthat intentional reciprocity, distributive concerns, and altruisticconsiderations all play a significant role in players' decisions.
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Previous indirect evidence suggests that impulses towards pro-socialbehavior are diminished when an external authority is responsiblefor an outcome. The responsibility-alleviation effect states that ashift of responsibility to an external authority dampens internalimpulses toward honesty, loyalty, or generosity. In a gift-exchangeexperiment, we find that subjects respond with more generosity(higher effort) when a wage is determined by a random process thanwhen it is assigned by a third party, indicating that even a slightshift in perceived responsibility for the final payoffs can changebehavior. Responsibility-alleviation is a factor in economicenvironments featuring substantial personal interaction.
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The first statement of the EUPHA on the Future of Public Health in Europe refers to the need for going 'to policymakers, politicians and practitioners in all sectors of society and advise them on how to promote public health throughout society'. WHO-EURO Director General Marc Danzon, quoted in the second EUPHA statement on the responsibility of policy makers indicates that 'learning is not systematically applied in health policy development in our continent'. Statement 3 calls for the integration of public health into the political agenda in all sectors. The first EUPHA president, Louise Gunning-Schepers, quoted in Statement 10 called on EUPHA to become 'a powerful advocate of the public health community'. In addition to the above, the EU is now actively seeking ways to build capacity to implement its health strategy. Learning and building the capacity to achieve our aims The aims and objectives to promote the public's health as reflected in EUPHA's 10 statements are also mirrored in the national public health associations. However, many of EUPHA's national associations have little or limited experience in promoting public health policy at the national level. To assist in the learning of advocacy for public health policies, case studies presenting experiences of national public health organizations in lobbying for national public health policy will be presented and discussed. In addition to sharing experiences, the presentations will identify successful approaches to public health advocacy as well as lessons learned from unsuccessful attempts.
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This study aimed at evaluating the biological characteristics and the capacity of parasitism of a Trichogramma pretiosum Riley, 1869 (Hymenoptera, Trichogrammatidae) strain (T. pretiosum RV) collected in Rio Verde County, State of Goiás, Brazil. The study was carried out on eggs of Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera, Noctuidae) and conducted under controlled environmental conditions at different constant temperatures. The biological parameters determined were: developmental time (egg-adult; days); emergence (%); sex ratio; number of progeny/egg; number of generation/year; thermal constant (K); temperature threshold (Tb); daily number of parasitized eggs; cumulative parasitism (%); total number of eggs parasitized by T. pretiosum; and female longevity. To study the T. pretiosum parasitism capacity, 20 S. frugiperda eggs (< 24 h old) were placed into 8.0 cm x 2.0 cm glass vials containing one female (< 24 h old) each. Trials were carried out in a completely randomized experimental design, with 20 replications at each temperature. The environmental chambers (BOD type) were set at 18ºC, 20ºC, 22ºC, 25ºC, 28ºC and 32ºC ± 1ºC, 70 ±10% relative humidity, and 14/10 h (L:D) photoperiod. The eggs of S. frugiperda were replaced daily until parasitoid death. Results have shown an inverse correlation between developmental time and temperature, with statistically significant differences among means, except at 25ºC and 28ºC (10 days). Parasitoid emergence (%) was also influenced by temperature. The lowest percent emergence was observed at 32ºC, and the highest ones at 18ºC and 20ºC temperatures. The temperature did not affect T. pretiosum sex ratio and number of parasitoids per egg, thus allowing changes in the temperature to control insect mass production in the laboratory to meet the needs for field releases.
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We lay out a small open economy version of the Calvo sticky price model, and show how the equilibrium dynamics can be reduced to simple representation in domestic inflation and the output gap. We use the resulting framework to analyze the macroeconomic implications of three alternative rule-based policy regimes for the small open economy: domestic inflation and CPI-based Taylor rules, and an exchange rate peg. We show that a key difference amongthese regimes lies in the relative amount of exchange rate volatility that they entail. We also discuss a special case for which domestic inflation targeting constitutes the optimal policy, and where a simple second order approximation to the utility of the representative consumer can be derived and used to evaluate the welfare losses associated with the suboptimal rules.
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After the accounting scandals that have taken place mainly in the UnitedStates during the last years, some Spanish leading authorities havedefended the idea that this kind of accounting problems cannot happen inSpain. They argue that accounting regulation in Europe, and specificallyin Spain, make more difficult the use of creative accounting practices.The objective of this paper is to identify some evidence about thesituacion in Spain. The study tries to demonstrate that some accountingpractices of several of the companies quoted in the Spanish Stock Exchangecould be qualified as earnings management.To carry out this study, the authors have analysed the accounts of the 35companies included in the stock market index IBEX 35. This index iscalculated with the share prices variations of the most importantcompanies quoted in the Spanish Stock Exchange.
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Purpose of the evaluation This is a scheduled standard mid-term evaluation (MTR) of a UNDP implemented GEF LDCF co-financed project. It is conducted by a team of an international and a national independent evaluator. The objective of the MTR, as set out in the Terms of Reference (TORs; Annex 1), is to provide an independent analysis of the progress of the project so far. The MTR aims to: identify potential project design problems, assess progress towards the achievement of the project objective and outcomes, identify and document lessons learned (including lessons that might improve design and implementation of other projects, including UNDP-GEF supported projects), and make recommendations regarding specific actions that should be taken to improve the project. The MTR is intended to assess signs of project success or failure and identify the necessary changes to be made. The project commenced its implementation in the first half of 2010 with the recruitment of project staff. According to the updated project plan, it is due to close in July 201410 with operations scaling down in December 2013 due to funding limits. Because of a slow implementation start, the mid-term evaluation was delayed to July 201311 The intended target audience of the evaluation are: The project team and decision makers in the INGRH The GEF and UNFCCC Operational Focal Points The project partners and beneficiaries UNDP in Cape Verde as well as the regional and headquarter (HQ) office levels The GEF Secretariat.
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While the theoretical industrial organization literature has long arguedthat excess capacity can be used to deter entry into markets, there islittle empirical evidence that incumbent firms effectively behave in thisway. Bagwell and Ramey (1996) propose a game with a specific sequence ofmoves and partially-recoverable capacity costs in which forward inductionprovides a theoretical rationalization for firm behavior in the field. Weconduct an experiment with a game inspired by their work. In our data theincumbent tends to keep the market, in contrast to what the forwardinduction argument of Bagwell and Ramey would suggest. The results indicatethat players perceive that the first mover has an advantage without havingto pre-commit capacity. In our game, evolution and learning do not driveout this perception. We back these claims with data analysis, atheoretical framework for dynamics, and simulation results.
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This paper offers empirical evidence that a country's choice of exchange rate regime can have a signifficant impact on its medium-term rate of productivity growth. Moreover, the impact depends critically on the country's level of financial development, its degree of market regulation, and its distance from the global technology frontier. We illustrate how each of these channels may operate in a simple stylized growth model in which real exchange rate uncertainty exacerbates the negative investment e¤ects of domestic credit market constraints. The empirical analysis is based on an 83 country data set spanning the years 1960-2000. Our approach delivers results that are in striking contrast to the vast existing empirical exchange rate literature, which largely finds the effects of exchange rate volatility on real activity to be relatively small and insignificant.
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This study aimed to evaluate the development, survival and reproductive capacity of Spodoptera eridania in four soybean cultivars. The experiment was conducted in the laboratory, in a climatic chamber at 25 °C ± 1 °C, 70 ± 10% relative humidity and 12 h photophase. The cultivars used were: FMT Tabarana, BRS/MT Pintado, FMT Tucunaré and Monsoy 8757, all conventional cultivars with medium cycles. All cultivars tested allowed the development of S. eridania. However, Monsoy 8757 was the cultivar that most affected the prolonged in the duration larval, pupal and total cycle, showed lower pupal weight as well as reduction in the intrinsic rate increase. These results contribute to the management of this species in regions of outbreaks in soybean areas.
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Preface In this thesis we study several questions related to transaction data measured at an individual level. The questions are addressed in three essays that will constitute this thesis. In the first essay we use tick-by-tick data to estimate non-parametrically the jump process of 37 big stocks traded on the Paris Stock Exchange, and of the CAC 40 index. We separate the total daily returns in three components (trading continuous, trading jump, and overnight), and we characterize each one of them. We estimate at the individual and index levels the contribution of each return component to the total daily variability. For the index, the contribution of jumps is smaller and it is compensated by the larger contribution of overnight returns. We test formally that individual stocks jump more frequently than the index, and that they do not respond independently to the arrive of news. Finally, we find that daily jumps are larger when their arrival rates are larger. At the contemporaneous level there is a strong negative correlation between the jump frequency and the trading activity measures. The second essay study the general properties of the trade- and volume-duration processes for two stocks traded on the Paris Stock Exchange. These two stocks correspond to a very illiquid stock and to a relatively liquid stock. We estimate a class of autoregressive gamma process with conditional distribution from the family of non-central gamma (up to a scale factor). This process was introduced by Gouriéroux and Jasiak and it is known as Autoregressive gamma process. We also evaluate the ability of the process to fit the data. For this purpose we use the Diebold, Gunther and Tay (1998) test; and the capacity of the model to reproduce the moments of the observed data, and the empirical serial correlation and the partial serial correlation functions. We establish that the model describes correctly the trade duration process of illiquid stocks, but have problems to adjust correctly the trade duration process of liquid stocks which present long-memory characteristics. When the model is adjusted to volume duration, it successfully fit the data. In the third essay we study the economic relevance of optimal liquidation strategies by calibrating a recent and realistic microstructure model with data from the Paris Stock Exchange. We distinguish the case of parameters which are constant through the day from time-varying ones. An optimization problem incorporating this realistic microstructure model is presented and solved. Our model endogenizes the number of trades required before the position is liquidated. A comparative static exercise demonstrates the realism of our model. We find that a sell decision taken in the morning will be liquidated by the early afternoon. If price impacts increase over the day, the liquidation will take place more rapidly.
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This paper describes an optimized model to support QoS by mean of Congestion minimization on LSPs (Label Switching Path). In order to perform this model, we start from a CFA (Capacity and Flow Allocation) model. As this model does not consider the buffer size to calculate the capacity cost, our model- named BCA (Buffer Capacity Allocation)- take into account this issue and it improve the CFA performance. To test our proposal, we perform several simulations; results show that BCA model minimizes LSP congestion and uniformly distributes flows on the network
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Two retrospective epidemiologic studies have shown that cannabis is the main psychoactive substance detected in the blood of drivers suspected of driving under the influence of psychotropic drugs. An oral administration double-blind crossover study was carried out with eight healthy male subjects, aged 22 to 30 years, all occasional cannabis smokers. Three treatments and one placebo were administered to all participants at a two week interval: 20 mg dronabinol, 16.5 mg D9-tétrahydrocannabinol (THC) and 45.7 mg THC as a cannabis milk decoction. Participants were asked to report the subjective drug effects and their willingness to drive under various circumstances on a visual analog scale. Clinical observations, a psychomotor test and a tracking test on a driving simulator were also carried out. Compared to cannabis smoking, THC, 11-OH-THC and THC-COOH blood concentrations remained low through the whole study (<13.1 ng THC/mL,<24.7 ng 11-OH-THC/mL and<99.9 ng THC-COOH/mL). Two subjects experienced deep anxiety symptoms suggesting that this unwanted side-effect may occur when driving under the influence of cannabis or when driving and smoking a joint. No clear association could be found between these adverse reactions and a susceptibility gene to propensity to anxiety and psychotic symptoms (genetic polymorphism of the catechol-O-methyltransferase). The questionnaires have shown that the willingness to drive was lower when the drivers were assigned an insignificant task and was higher when the mission was of crucial importance. The subjects were aware of the effects of cannabis and their performances on the road sign and tracking test were greatly impaired, especially after ingestion of the strongest dose. The Cannabis Influence Factor (CIF) which relies on the molar ratio of active and inactive cannabinoids in blood provided a good estimate of the fitness to drive.