1,488 research outputs found
Asymptotic and bootstrap specification tests of nonlinear in variable econometric models
We address the issue of consistent specification testing in general econometric models definedı by multiple moment conditions. We develop two c1asses of moment conditions based tests. The first class of tests depends upon nonparametric functions that are estimated by kernel smoothers. The second class of tests depends upon a marked empirical process. Asymptotic and bootstrap versions of these tests are formally justified, and their finite sample performances are investigated by means of Monte-CarIo experiments
Consistent tests of conditional moment restrictions
We propose two classes of consistent tests in parametric econometric models defined through multiple conditional moment restrictions. The first type of tests relies on nonparametric estimation, while the second relies on a functional of a marked empirical process. For both tests, a simulation procedure for obtaining critical values is shown to be asymptotically valid. Finite sample performances of the tests are investigated by means of several Monte-Carlo experiments.Publicad
Semiparametric estimation and testing in models of adverse selection, with an aplication to environmental regulation
We propose a flexible framework for estimating and testing structural models with adverse selection. This framework uses semiparametric methods for estimating consistently structural parameters of interest and for assesssing the results by testing procedures. We consider a problem of environmental regulation where firms are regulated through contracts. We show how to check parametric assumptions for the abatement cost function and test for neglected adverse selection. We then apply a semiparametric procedure for estimating models with adverse selection, that does not require to specify the distribution of the private information and avoids costly numerical procedures. The proposed framework can prove useful in a wide variety of problems where adverse selection can be present
âI Didnât Have to Prove to Anybody That I Was a Good Candidateâ: A Case Study Framing International Bariatric Tourism by Canadians as Circumvention Tourism
Background Medical tourism is a practice where patients travel internationally to purchase medical services. Medical tourists travel abroad for reasons including costly care, long wait times for care, and limited availability of desired procedures stemming from legal and/or regulatory restrictions. This paper examines bariatric (weight loss) surgery obtained abroad by Canadians through the lens of âcircumvention tourismâ â typically applied to cases of circumvention of legal barriers but here applied to regulatory circumvention. Despite bariatric surgery being available domestically through public funding, many Canadians travel abroad to obtain these surgeries in order to circumvent barriers restricting access to this care. Little, however, is known about why these barriers push some patients to obtain these surgeries abroad and the effects of this circumvention.
Methods Semi-structured phone interviews were conducted with 20 former Canadian bariatric tourists between February and May of 2016. Interview questions probed patientsâ motivations for seeking care abroad, as well as experiences with attempting to obtain care domestically and internationally. Interviews were digitally recorded, transcribed verbatim, and then thematically analyzed.
Results Three key barriers to access were identified: (1) structural barriers resulting in limited locally available options; (2) strict body mass index cut-off points to qualify for publicly-funded surgery; and (3) the extended wait-time and level of commitment required of the mandatory pre-operative program in Canada. It was not uncommon for participants to experience a combination, if not all, of these barriers.
Conclusions Collectively, these barriers restricting domestic access to bariatric care in Canada may leave Canadian patients with a sense that their health care system is not adequately addressing their specific health care needs. In circumventing these barriers, patients may feel empowered in their health care opportunities; however, significant concerns are raised when patients bypass protections built into the health system. Given the practical limitations of a publicly funded health care system, these barriers to care are likely to persist. Health professionals and policy makers in Canada should consider these barriers in the future when examining the implications medical tourism for bariatric surgery holds for Canadians
Citizen Science Time Domain Astronomy with Astro-COLIBRI
Astro-COLIBRI is an innovative tool designed for professional astronomers to
facilitate the study of transient astronomical events. Transient events - such
as supernovae, gamma-ray bursts and stellar mergers - are fleeting cataclysmic
phenomena that can offer profound insights into the most violent processes in
the universe. Revealing their secrets requires rapid and precise observations:
Astro-COLIBRI alerts its users of new transient discoveries from observatories
all over the world in real-time. The platform also provides observers the
details they need to make follow-up observations.
Some of the transient phenomena available through Astro-COLIBRI are
accessible by amateur astronomers and citizen scientists. A subset of the
features dedicated to this growing group of users are highlighted here. They
include the possibility of receiving only alerts on very bright events, the
possibility of defining custom observer locations, as well as the calculation
of optimized observation plans for searches for optical counterparts to
gravitational wave events.Comment: Proceedings Atelier Pro-AM Gemini, Journ\'ees SF2A 2023. arXiv admin
note: text overlap with arXiv:2308.0704
Snell\u27s Law of Refraction Observed in Thermal Frontal Polymerization
We demonstrate that Snellâs law of refraction can be applied to thermal fronts propagating through a boundary between regions that support distinct frontal velocities. We use the free-radical frontal polymerization of a triacrylate with clay filler that allows for two domains containing two different concentrations of a peroxide initiator to be molded together. Because the polymerization reaction rates depend on the initiator concentration, the propagation speed is different in each domain. We study fronts propagating in two parallel strips in which the incident angle is 90°. Our data fit Snellâs law vr/vi = sin Ξr/sin Ξi, where vr is the refracted velocity, vi is the incident velocity, Ξr is the angle of refraction, and Ξi is the incident angle. Further, we study circular fronts propagating radially from an initiation point in a high-velocity region into a low-velocity region (and vice versa). We demonstrate the close resemblance between the numerically simulated and experimentally observed thermal reaction fronts. By measuring the normal velocity and the angle of refraction of both simulated and experimental fronts, we establish that Snellâs law holds for thermal frontal polymerization in our experimental system. Finally we discuss the regimes in which Snellâs law may not be valid
Getting To Excellence: What Every Educator Should Know About Consequences of Beliefs, Attitudes, and Paradigms for the Reconstruction of an Academically Unacceptable Middle School
In this chapter a discussion of a salient dimension of the external environment in which todayâs educators find themselves practicing â the policy context - is presented. Critical elements of this discussion include a truncated history of the encroachment on local control of the schools and the ensuing standardized-tests-based accountability and standardized testing movement. We also pay some attention to growing efforts to push back against these movements. We conclude this chapter with perspectives of a set of scholarly informants on quality, equity, and adequacy. Our effort in this chapter is to trace the political distance traveled from education defined by the diverse beliefs, values, attitudes and paradigms specific to the New England, Middle, and Southern colonies to the current emphasis on standardized-tests-based accountability, standards, and testing as they impact or fail to impact quality, equity, and adequacy â the context in which the Willie Ray Smith, Sr. Science and Medical Technology Magnet Middle School was previously branded academically unacceptable but now academically acceptable
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