scholarly journals Randomization and Ambiguity Aversion

Econometrica ◽  
2020 ◽  
Vol 88 (3) ◽  
pp. 1159-1195 ◽  
Author(s):  
Shaowei Ke ◽  
Qi Zhang

We propose a model of preferences in which the effect of randomization on ambiguity depends on how the unknown probability law is determined. We adopt the framework of Anscombe and Aumann (1963) and relax the axioms. In the resulting representation of the individual's preference, the individual has a collection of sets of priors M . She believes that before she moves, nature has chosen an unknown scenario (a set of priors) from M , and from that scenario, nature will choose a prior after she moves. The representation illustrates how randomization may partially eliminate the effect of ambiguity.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Divya Aggarwal ◽  
Uday Damodaran ◽  
Pitabas Mohanty ◽  
D. Israel

PurposeThis study examines individual ambiguity attitudes alone and in groups by leveraging the descriptive model of anchoring and adjustment on decision-making under ambiguity. The study extends Ellsberg's probability ambiguity to outcome ambiguity and examines decisions made under both ambiguities, at different likelihood levels and under the domain of gains and losses.Design/methodology/approachThe methodology selected for this study is a two-stage within-subject lab experiment, with participants from different Indian universities. Each participant made 12 lottery decisions at the individual level and at individuals in the group level.FindingsThe results show that ambiguity attitudes are not universal in nature. Ambiguity seeking as a dominant choice was observed at both the individual level and at individual in the group level. However, the magnitude of ambiguity seeking or ambiguity aversion contingent upon the domain of gains and losses differed widely across the individual level and at individuals in the group level.Research limitations/implicationsThe study enables to contribute toward giving a robust descriptive explanation for individual behavior in real-world applications of finance. It aims to provide direction for theoretical normative models to accommodate heterogeneity of ambiguity attitudes.Originality/valueThe study is novel as it examines a two-dimensional approach by representing ambiguity in probability and in outcomes. It also analyzes whether decisions under ambiguity vary when individuals make decisions alone and when they make it in groups.


2011 ◽  
pp. 16-34
Author(s):  
I. Pavlov

The paper analyzes ambiguity aversion that is one of the main anomalies characteristic for the individual behaviour of economic agents making choice in the face of uncertainty. It shows that this phenomenon plays a major role in the contemporary rational choice theory and hence is widely discussed both by economic theorists and experimental economists. The article further elaborates on the nature of this phenomenon and considers its main causes.


Author(s):  
C.N. Sun

The present study demonstrates the ultrastructure of the gingival epithelium of the pig tail monkey (Macaca nemestrina). Specimens were taken from lingual and facial gingival surfaces and fixed in Dalton's chrome osmium solution (pH 7.6) for 1 hr, dehydrated, and then embedded in Epon 812.Tonofibrils are variable in number and structure according to the different region or location of the gingival epithelial cells, the main orientation of which is parallel to the long axis of the cells. The cytoplasm of the basal epithelial cells contains a great number of tonofilaments and numerous mitochondria. The basement membrane is 300 to 400 A thick. In the cells of stratum spinosum, the tonofibrils are densely packed and increased in number (fig. 1 and 3). They seem to take on a somewhat concentric arrangement around the nucleus. The filaments may occur scattered as thin fibrils in the cytoplasm or they may be arranged in bundles of different thickness. The filaments have a diameter about 50 A. In the stratum granulosum, the cells gradually become flatted, the tonofibrils are usually thin, and the individual tonofilaments are clearly distinguishable (fig. 2). The mitochondria and endoplasmic reticulum are seldom seen in these superficial cell layers.


Author(s):  
Anthony J. Godfrey

Aldehyde-fixed chick retina was embedded in a water-containing resin of glutaraldehyde and urea, without dehydration. The loss of lipids and other soluble tissue components, which is severe in routine methods involving dehydration, was thereby minimized. Osmium tetroxide post-fixation was not used, lessening the amount of protein denaturation which occurred. Ultrathin sections were stained with 1, uranyl acetate and lead citrate, 2, silicotungstic acid, or 3, osmium vapor, prior to electron microscope examination of visual cell outer segment ultrastructure, at magnifications up to 800,000.Sections stained with uranyl acetate and lead citrate (Fig. 1) showed that the individual disc membranes consisted of a central lipid core about 78Å thick in which dark-staining 40Å masses appeared to be embedded from either side.


Author(s):  
Anthony A. Paparo ◽  
Judith A. Murphy

The purpose of this study was to localize the red neuronal pigment in Mytilus edulis and examine its role in the control of lateral ciliary activity in the gill. The visceral ganglia (Vg) in the central nervous system show an over al red pigmentation. Most red pigments examined in squash preps and cryostat sec tions were localized in the neuronal cell bodies and proximal axon regions. Unstained cryostat sections showed highly localized patches of this pigment scattered throughout the cells in the form of dense granular masses about 5-7 um in diameter, with the individual granules ranging from 0.6-1.3 um in diame ter. Tissue stained with Gomori's method for Fe showed bright blue granular masses of about the same size and structure as previously seen in unstained cryostat sections.Thick section microanalysis (Fig.l) confirmed both the localization and presence of Fe in the nerve cell. These nerve cells of the Vg share with other pigmented photosensitive cells the common cytostructural feature of localization of absorbing molecules in intracellular organelles where they are tightly ordered in fine substructures.


Author(s):  
William W. Thomson ◽  
Elizabeth S. Swanson

The oxidant air pollutants, ozone and peroxyacetyl nitrate, are produced in the atmosphere through the interaction of light with nitrogen oxides and gaseous hydrocarbons. These oxidants are phytotoxicants and are known to deleteriously affect plant growth, physiology, and biochemistry. In many instances they induce changes which lead to the death of cells, tissues, organs, and frequently the entire plant. The most obvious damage and biochemical changes are generally observed with leaves.Electron microscopic examination of leaves from bean (Phaseolus vulgaris L.) tobacco (Nicotiana tabacum L.) and cotton (Gossipyum hirsutum L.) fumigated for .5 to 2 hours with 0.3 -1 ppm of the individual oxidants revealed that changes in the ultrastructure of the cells occurred in a sequential fashion with time following the fumigation period. Although occasional cells showed severe damage immediately after fumigation, the most obvious change was an enhanced clarity of the cell membranes.


Author(s):  
D. E. Becker

An efficient, robust, and widely-applicable technique is presented for computational synthesis of high-resolution, wide-area images of a specimen from a series of overlapping partial views. This technique can also be used to combine the results of various forms of image analysis, such as segmentation, automated cell counting, deblurring, and neuron tracing, to generate representations that are equivalent to processing the large wide-area image, rather than the individual partial views. This can be a first step towards quantitation of the higher-level tissue architecture. The computational approach overcomes mechanical limitations, such as hysterisis and backlash, of microscope stages. It also automates a procedure that is currently done manually. One application is the high-resolution visualization and/or quantitation of large batches of specimens that are much wider than the field of view of the microscope.The automated montage synthesis begins by computing a concise set of landmark points for each partial view. The type of landmarks used can vary greatly depending on the images of interest. In many cases, image analysis performed on each data set can provide useful landmarks. Even when no such “natural” landmarks are available, image processing can often provide useful landmarks.


Author(s):  
B. Carragher ◽  
M. Whittaker

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.


2015 ◽  
Vol 24 (3) ◽  
pp. 74-85
Author(s):  
Sandra M. Grether

Individuals with Rett syndrome (RS) present with a complex profile. They benefit from a multidisciplinary approach for diagnosis, treatment, and follow-up. In our clinic, the Communication Matrix © (Rowland, 1990/1996/2004) is used to collect data about the communication skills and modalities used by those with RS across the lifespan. Preliminary analysis of this data supports the expected changes in communication behaviors as the individual with RS ages and motor deficits have a greater impact.


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