A three-stage experimental test of revealed preference

A powerful test of Varian's (1982) generalised axiom of revealed preference (GARP) with two goods requires the consumer's budget line to pass through two demand vectors revealed as chosen given other budget sets. In an experiment using this idea, each of 41 student subjects faced a series of 16 successive grouped portfolio selection problems. Each group of selection problems had up to three stages, where later budget sets depended on that subject'choices at earlier stages in the same group. Only 49% of subjects' choices were observed to satisfy GARP exactly, even by our relatively generous nonparametric test

A Three-Stage Experimental Test of Revealed Preference

A powerful test of Varian's (1982) generalised axiom of revealed preference (GARP) with two goods requires the consumer's budget line to pass through two demand vectors revealed as chosen given other budget sets. In an experiment using this idea, each of 41 student subjects faced a series of 16 successive grouped portfolio selection problems. Each group of selection problems had up to three stages, where later budget sets depended on that subject's choices at earlier stages in the same group. Only 49% of subjects' choices were observed to satisfy GARP exactly, even by our relatively generous nonparametric test.Rationality, revealed preference, uncertainty

Simple fecal flotation is a superior alternative to guadruple Kato Katz smear examination for the detection of hookworm eggs in human stool

Microscopy-based identification of eggs in stool offers simple, reliable and economical options for assessing the prevalence and intensity of hookworm infections, and for monitoring the success of helminth control programs. This study was conducted to evaluate and compare the diagnostic parameters of the Kato-Katz (KK) and simple sodium nitrate flotation technique (SNF) in terms of detection and quantification of hookworm eggs, with PCR as an additional reference test in stool, collected as part of a baseline cross-sectional study in Cambodia.; Fecal samples collected from 205 people in Dong village, Rovieng district, Preah Vihear province, Cambodia were subjected to KK, SNF and PCR for the detection (and in case of microscopy-based methods, quantification) of hookworm eggs in stool. The prevalence of hookworm detected using a combination of three techniques (gold standard) was 61.0%. PCR displayed a highest sensitivity for hookworm detection (92.0%) followed by SNF (44.0%) and quadruple KK smears (36.0%) compared to the gold standard. The overall eggs per gram feces from SNF tended to be higher than for quadruple KK and the SNF proved superior for detecting low egg burdens.; As a reference, PCR demonstrated the higher sensitivity compared to SNF and the quadruple KK method for detection of hookworm in human stool. For microscopic-based quantification, a single SNF proved superior to the quadruple KK for the detection of hookworm eggs in stool, in particular for low egg burdens. In addition, the SNF is cost-effective and easily accessible in resource poor countries

Land Use Change Detection and Urban Sprawl Monitoring in Metropolitan Area of Jakarta (Jabodetabek) from 2001 to 2015

Being 13th largest city in the world makes Jakarta as a fascinating city in South East Asia. Its surrounding regions are included in a particular metropolitan area called “Jabodetabek”. Population growth in this metropolitan area about 10 million only in 15 years from 2000 to 2015. Consequently, loss of vegetation and agricultural land, less water resources, increasing demand for housing and transportation infrastructure as the effect of this ever-growing population take place. This phenomenon can be detected using Landsat satellites images. The settlement or urban area in Jabodetabek shows a huge increase in percentage from 2001 to 2015, so much that the urban area is the dominant land cover and reaches up to 61 percent of Jabodetabek in year 2015. Moreover settlement density in Jabodetabek (ring zones 25 to 45 km from central city) shows an increase of more than 20% urban areas in year 2015. Furthermore, the result of compactness reveals that this urban expansion in Jabodetabek was spread out from 2001 to 2008 and became more compacted by 2015

Does Epileptiform Activity Represent a Failure of Neuromodulation to Control Central Pattern Generator-Like Neocortical Behavior?

Rhythmic motor patterns in invertebrates are often driven by specialized "central pattern generators" (CPGs), containing small numbers of neurons, which are likely to be "identifiable" in one individual compared with another. The dynamics of any particular CPG lies under the control of modulatory substances, amines, or peptides, entering the CPG from outside it, or released by internal constituent neurons; consequently, a particular CPG can generate a given rhythm at different frequencies and amplitudes, and perhaps even generate a repertoire of distinctive patterns. The mechanisms exploited by neuromodulators in this respect are manifold: Intrinsic conductances (e.g., calcium, potassium channels), conductance state of postsynaptic receptors, degree of plasticity, and magnitude and kinetics of transmitter release can all be affected. The CPG concept has been generalized to vertebrate motor pattern generating circuits (e.g., for locomotion), which may contain large numbers of neurons - a construct that is sensible, if there is enough redundancy: that is, the large number of neurons consists of only a small number of classes, and the cells within any one class act stereotypically. Here we suggest that CPG and modulator ideas may also help to understand cortical oscillations, normal ones, and particularly transition to epileptiform pathology. Furthermore, in the case illustrated, the mechanism of the transition appears to be an exaggerated form of a normal modulatory action used to influence sensory processing

Spatially Resolved Circumstellar Structure of Herbig Ae/Be Stars in the Near-Infrared

We have conducted the first systematic study of Herbig Ae/Be stars using the technique of long baseline stellar interferometry in the near-infrared. The principal result of this paper is that the IOTA interferometer resolves the source of infrared excess in 11 of the 15 systems surveyed. The visibility data for all the sources has been interpreted within the context of four simple models which represent a range of plausible representations for the brightness distribution of the source of excess emission: a Gaussian, a narrow uniform ring, a flat blackbody disk with a single temperature power law, and an infrared companion. We find that the characteristic sizes of the near-infrared emitting regions are larger than previously thought (0.5-5.9 AU, as given by the FWHM of the Gaussian intensity). A further major result of this paper is that the sizes measured, when combined with the observed spectral energy distributions, essentially rule out accretion disk models represented by blackbody disks with the canonical radial temperature law with exponent -3/4. We also find that, within the range observed in this study, none of the sources (except the new binary) shows varying visibilities as the orientation of the interferometer baseline changes. Taken as an ensemble, with no clear evidence in favor of axi-symmetric structure, the observations favor the interpretation that the circumstellar dust is distributed in spherical envelopes (the Gaussian model) or thin shells (the ring model).Comment: Accepted for publication by The Astrophysical Journa