Modeling Exit and Entry of Farmers in a Crop Insurance Program

This paper examines the factors influencing farmer participation in crop insurance schemes, but unlike previous studies that focus on total demand, participation is disaggregated into entrants and those exiting. Modeling entry and exit decisions separately illustrates that the effect of a given variable is often muted by aggregation. In addition, the approach in this paper distinguishes between price and yield variables rather than total returns and is consequently able to demonstrate that price variables are particularly important for farmers considering enrolling in crop insurance, while yield variables and other risk management opportunities are more important for farmers who have been in the program but are deciding to exit. The result suggests that moral hazard is reduced significantly by calculating the coverage yield level for an individual producer on the basis of a moving average of past yields for that farmer. While yield and its variance are particularly influential in the participation decision for farmers currently enrolled, its significant impact on the insurance decision for all farmers highlights the importance of crop insurance as a potential adaptation strategy to weather events.crop insurance, entry and exit, panel data, Risk and Uncertainty,

Use of Urinary Pregnanediol 3-glucuronide to Confirm Ovulation

Objective Urinary hormonal markers may assist in increasing the efficacy of Fertility Awareness Based Methods (FABM). This study uses urinary pregnanediol-3a-glucuronide (PDG) testing to more accurately identify the infertile phase of the menstrual cycle in the setting of FABM. Methods Secondary analysis of an observational and simulation study, multicentre, European study. The study includes 107 women and tracks daily first morning urine (FMU), observed the changes in cervical mucus discharge, and ultrasonography to identify the day of ovulation over 326 menstrual cycles. The following three scenarios were tested: (A) use of the daily pregnandiol-3a-glucuronide (PDG) test alone; (B) use of the PDG test after the first positive urine luteinizing hormone (LH) kit result; (C) use of the PDG test after the disappearance of fertile type mucus. Two models were used: (1) one day of PDG positivity; or (2) waiting for three days of PDG positivity before declaring infertility. Results After the first positivity of a LH test or the end of fertile mucus, three consecutive days of PDG testing over a threshold of 5 μg/mL resulted in a 100% specificity for ovulation confirmation. They were respectively associated an identification of an average of 6.1 and 7.6 recognized infertile days. Conclusions The results demonstrate a clinical scenario with 100% specificity for ovulation confirmation and provide the theoretical background for a future development of a competitive lateral flow assay for the detection of PDG in the urine

Birnbaum–Saunders autoregressive conditional duration models applied to high-frequency financial data

Modern financial markets now record the precise time of each stock trade, along with price and volume, with the aim of analysing the structure of the times between trading events—leading to a big data problem. In this paper, we propose and compare two Birnbaum–Saunders autoregressive conditional duration models specified in terms of time-varying conditional median and mean durations. These models provide a novel alternative to the existing autoregressive conditional duration models due to their flexibility and ease of estimation. Diagnostic tools are developed to allow goodness-of-fit assessment and to detect departures from assumptions, including the presence of outliers and influential cases. These diagnostic tools are based on the parameter estimates using residual analysis and the Cook distance for global influence, and different perturbation schemes for local influence. A thorough Monte Carlo study is presented to evaluate the performance of the maximum likelihood estimators, and the forecasting ability of the models is assessed using the traditional and density forecast evaluation techniques. The Monte Carlo study suggests that the parameter estimators are asymptotically unbiased, consistent and normally distributed. Finally, a full analysis of a real-world financial transaction data set, from the German DAX in 2016, is presented to illustrate the proposed approach and to compare the fitting and forecasting performances with existing models in the literature. One case related to the duration time is identified as potentially influential, but its removal does not change resulting inferences demonstrating the robustness of the proposed approach. Fitting and forecasting performances favor the proposed models and, in particular, the median-based approach gives additional protection against outliers, as expected

Stochastic inversion of linear first kind integral equations I. Continuous theory and the stochastic generalized inverse

The dataset associated with this paper is in ORE; see http://hdl.handle.net/10871/17644© 2015 American Psychological AssociationThis article may not exactly replicate the final version published in the APA journal. It is not the copy of record.This paper is made available in accordance with publisher policies. The final published version of this article is available from the publisher’s site. at http://www.apa.org/pubs/journals/xhp/index.aspxBefore reusing this item please check the rights under which it has been made available. Some items are restricted to non-commercial use. Please cite the published version where applicable.The present study explores the link between attentional reorienting and response inhibition. Recent behavioral and neuroscience work indicates that both might rely on similar cognitive and neural mechanisms. We tested two popular accounts of the overlap: The ‘circuit breaker’ account, which assumes that unexpected events produce global suppression of motor output, and the ‘stimulus detection’ account, which assumes that attention is reoriented to unexpected events. In Experiment 1, we presented standard and (unexpected) novel sounds in a go/no-go task. Consistent with the stimulus detection account, we found longer RTs on go trials and higher rates of commission errors on no-go trials when these were preceded by a novel sound compared with a standard sound. In Experiment 2, novel and standard sounds acted as no-go signals. In this experiment, the novel sounds produced an improvement on no-go trials. This further highlights the importance of stimulus detection for response inhibition. Combined, the two experiments support the idea that attention is oriented to novel or unexpected events, impairing no-go performance if these events are irrelevant but enhancing no-go performance when they are relevant. Our findings also indicate that the popular circuit breaker account of the overlap between response inhibition and attentional reorienting needs some revision.European Research CouncilFPU Fellowshi

Finite Time Synchronization of Extended Nonlinear Dynamical Systems Using Local Coupling

We consider two reaction-diffusion equations connected by one-directional coupling function and study the synchronization problem in the case where the coupling function affects the driven system in some specific regions. We derive conditions that ensure that the evolution of the driven system closely tracks the evolution of the driver system at least for a finite time. The framework built to achieve our results is based on the study of an abstract ordinary differential equation in a suitable Hilbert space. As a specific application we consider the Gray-Scott equations and perform numerical simulations that are consistent with our main theoretical results

Orbital evolution of circumbinary planets due to creep tides

Most confirmed circumbinary planets are located very close to their host binary where the tidal forces are expected to play an important role in their dynamics. Here we consider the orbital evolution of a circumbinary planet with arbitrary viscosity, subjected to tides due to both central stars. We adopt the creep tide theory and assume that the planet is the only extended body in the system and that its orbital evolution occurs after acquiring its pseudo-synchronous stationary rotational state. With this aim, we first performed a set of numerical integrations of the tidal equations, using a Kepler-38-type system as a working example. For this case we find that the amount of planetary tidal migration and also, curiously, its direction both depend on the viscosity. However, the effect of tides on its eccentricity and pericenter evolutions is simply a move toward pure gravitational secular solutions. Then we present a secular analytical model for the planetary semimajor axis and eccentricity evolution that reproduces very well the mean behavior of the full tidal equations and provides a simple criterion to determine the migration directions of the circumbinary planets. This criterion predicts that some of the confirmed circumbinary planets are tidally migrating inward, but others are migrating outward. However, the typical timescales are predicted to be very long, and not much orbital tidal evolution is expected to have taken place in these systems. Finally, we revisit the orbital evolution of a circumbinary planet in the framework of the constant time lag model. We find that the results predicted with this formalism are identical to those obtained with creep theory in the limit of gaseous bodies.Fil: Zoppetti, Federico Andrés. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Grupo de Invest.en Astronomia Teórica y Exptal.; ArgentinaFil: Folonier, H.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Leiva, Alejandro Martín. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Gomes, G.O.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; Brasi

Estudio experimental de una barrera acústica compuesta de cenizas volantes

Although fly ash is commonly used as an additive to cement, large amounts of this material are disposed in landfills. To mitigate, it would be interesting to develop new products in which fly ash can be easily used and required in large quantities. In this work, fly ash is added to manufacture eco-friendly materials with acceptable acoustic and non-acoustic properties and a low cost. We built a barrier composed of fly ash (60 wt.%), type II Portland cement (25 wt.%), vermiculite (14.5 wt.%) and polypropylene fibers (0.5 wt.%). The barrier complied with the mechanical requirements of European standards. The sound absorption coefficient and the airborne sound insulation were determined in a reverberation room, and the barrier was classified as A2 and B3. No leaching problems were observed.Aunque las cenizas volantes se usan comúnmente como una adición en la fabricación del cemento, grandes cantidades se siguen depositando en vertedero. Para mitigar este problema, es interesante desarrollar nuevos productos en los que las cenizas volantes se puedan usar fácilmente en grandes cantidades. En este trabajo, se emplean cenizas volantes para fabricar materiales con una alta absorción acústica, con propiedades mecánicas aceptables y un bajo coste. Se ha construido una barrera compuesta de cenizas volantes (60% en peso), cemento Portland tipo II (25% en peso), vermiculita (14.5% en peso) y fibras de polipropileno (0.5% en peso). La barrera cumplió con los requisitos mecánicos establecidos de las normas europeas. El coeficiente de absorción acústica y el aislamiento acústico en el aire se han determinado en una sala de reverberación, y la barrera se clasificó como A2 y B3. No se han observado problemas de lixiviación

The Introduction of DTT in Latin America: Politics and Policies

The switch to digital terrestrial television is now a global trend. In Latin America, where the terrestrial platform has a dominant role, the introduction of DTT raises important questions for economic and industrial development, as well as pluralism. This article focuses on the earliest experiences (Brazil, México and Argentina) and those of the newcomers (Chile, Colombia and Uruguay). The aim is to outline the differences between the various political decision processes and the way with which they have been turned into communication policies, so as to draw some conclusions that contribute to visualizing the future of television in the region.Publicad

1-D Harmonic Oscillator in Snyder Space, the Classic and the Quantum

The 1-D dimension harmonic oscillator in Snyder space is investigated in its classical and quantum versions. The classical trajectory is obtained and the semiclassical quantization from the phase space trajectories is discussed. In the meanwhile, an effective cutoff to high frequencies is found. The quantum version is developed and an equivalent usual harmonic oscillator is obtained through an effective mass and an effective frequency introduced in the model. This modified parameters give us an also modified energy spectra.Comment: 8 pages, 2 figure