The Effect of Expertise on the Quality of Appraisal Services

This article examines the quality of appraisals as a function of expertise. In paraticular, we compare novices (beginning real estate students) to experts (practicing certified and/or designated appraisers) on three performance criteria. First, we examine differences in the values that these two groups attach to various property features. Second, we investigate the variation between their final market value estimates. The last task studied is whether appraisers can reliably provide a range about their market value that includes the actual sale price of the property. The results are based on a controlled experiment involving seventy-two novices and sixty-nine experts, where each participant was asked to determine a fair market value of a single-family home. Findings indicate that experienced appraisers do in fact exhibit less variation in their valuation of property characteristics, hence there is greater agreement in their market value estimates than is the case with novices. However, more experienced decision-makers tend to be overconfident of their ability: they are less likely to specify a range that includes the sale price than are novices.

Correcting political and consumer misperceptions

While fact-checking has grown dramatically in the last decade, little is known about the relative effectiveness of different formats in correcting false beliefs or overcoming partisan resistance to new information. This article addresses that gap by using theories from communication and psychology to compare two prevailing approaches: An online experiment examined how the use of visual “truth scales” interacts with partisanship to shape the effectiveness of corrections. We find that truth scales make fact-checks more effective in some conditions. Contrary to theoretical predictions and the fears of some journalists, their use does not increase partisan backlash against the correction or the organization that produced it

Compensated Deconvolution from Wavefront Sensing

The U.S. Air Force has a continuing mission to obtain imagery of earth-orbiting objects. One of the means for obtaining this imagery is through the use of ground-based observatories. A fundamental problem associated with imaging objects through the atmosphere is that atmospheric turbulence inflicts a large, random aberration on the telescope which effectively limits the realizable resolution to that of a much smaller telescope. Several approaches have been taken to overcome these effects including pure post processing, pure adaptive optics, and hybrid techniques involving both adaptive optics and image post processing. One key result from past approaches is that partially compensated systems can be used in conjunction with image processing to overcome most of the optical effects of atmospheric turbulence while retaining nearly the performance of a fully compensated system. One hybrid approach is compensated deconvolution from wavefront sensing (CDWFS). This method uses wavefront sensor measurements in conjunction with short exposure images to improve the effective optical performance. This thesis formulates and executes a plan which allows fundamental questions regarding partially compensated adaptive optics performance to be answered. Specifically, imaging of extended objects using the CDWFS technique is investigated, through simulation. The simulation results demonstrate that the CDWFS technique can be used to reduce the required closed-loop bandwidth of an imaging system, permitting longer integration times in the wavefront sensor, and thus allowing dimmer objects to be imaged without the use of an artificial guidestar

Occasional Paper No. 092-1: Health Care Perceptions of Nebraska\u27s Urban & Rural Aged

Random samples were drawn in Douglas County, Nebraska (N = 196, mean age = 73.8 years), in the counties surrounding Douglas County also served by the Eastern Nebraska Office on Aging (N = 104, mean age = 72.4 years), and in eleven of the rural Sandhills counties of Nebraska (N = 200, mean age = 76.6). Participants responded to structured interviews of 169 questions that included self-assessed health status, availability of health care and physician services, costs, attitudes toward health care services, health experiences and beliefs. While the Sandhills respondents were significantly older and had less access to health services, they also had fewer annual days of hospitalization. There were no differences in subjective ratings of health or in levels of satisfaction with health care or availability

\u3ci\u3eParavitellotrema overstreeti\u3c/i\u3e Sp. n. (Digenea: Hemiuridae) from the Colombian Freshwater Stingray \u3ci\u3ePotamotrygon magdalenae\u3c/i\u3e Dumeri

Paravitellotrema overstreeti from the freshwater stingray Potamotrygon magdalenae in northern Colombia most closely resembles P. thorsoni by possessing a muscular sinus organ and sinus sac as well as exhibiting a saccate rather than elongate prostatic vesicle, It differs by possessing lobate rather than spherical vitellaria, a smaller sinus organ and sinus sac, elongate rather than diamond-shaped prostatic cells enclosed in a delicate membrane rather than free in the parenchyma, and a metraterm joining the hermaphroditic duct immediately anterior to the prostatic vesicle rather than at the base of the sinus organ

Studies of the Potential Curve Crossing Problem I. Analysis of Stueckelberg\u27s Method

A detailed critical analysis is made of Stueckelberg\u27s treatment of inelastic transitions at a crossing of two potential curves. Using an asymptotic method analogous to the WKB approximation, Stueckelberg obtained the well-known Landau-Zener-Stueckelberg (LZS) formula for the inelastic transition probability. His method involved the determination of connection formulas linking amplitudes associated with his asymptotic approximants on either side of the crossing-point region. Here we show that (a) Stueckelberg\u27s asymptotic approximants are just the WKB approximants for elastic scattering on the adiabatic (noncrossing) potential curves; (b) Stueckelberg\u27s method for obtaining the connection formulas can be put on a rigorous footing, including sufficient conditions for its validity, using the classical trajectory equations derivable from a general semiclassical theory of inelastic atomic collisions; (c) there is an undetermined phase in the S matrix, which Stueckelberg incorrectly assumed to be zero, and which has the value 14π in the distorted-wave approximation; (d) Stueckelberg\u27s derivation is not valid whenever the inelastic transition probability is small, either in the rapid-passage (diabatic) case or the near-adiabatic limit; (e) for realistic model parameters, the conditions needed for Stueckelberg\u27s derivation to be valid are almost never satisfied. Since the LZS formula is known from numerical computations to be valid under some conditions when the Stueckelberg derivation is not valid, we conclude that analysis via connection-formula methods is not a useful technique for treating the crossing problem. In an appendix we derive an analytical result for the Stokes\u27s constants determining the Stueckelberg connection formulas. The result is an absolutely convergent, infinite series whose numerical evaluation would yield exactly the unknown phase associated with the LZS formula

Two New Species of \u3ci\u3eAcanthobothrium\u3c/i\u3e Van Beneden 1849 (Cestoidea: Tetraphyllidea) from Freshwater Stingrays in South America

Two new species of Acanthobothrium are reported from freshwater stingrays in northern South America. Acanthobothrium quinonesi sp. n. is described from Potamotrygon magdalenae Dumeril collected from the Magdalena River in northern Colombia and A. amazonensis sp. n. from P. circularis Garman collected in the Itacuai River of northwestern Brazil. Acanthobothrium quinonesi differs from A. amazonensis by having a smaller and anteriorly-curved cirrus sac, 43-60 rather than 50-72 testes, and bothridial hooks 100-142 μm long rather than 145-184 μm long. Characters used in the taxonomy of Acanthobothrium species are listed to show that the new species resemble each other and A. terezae, also from a South American freshwater stingray, more than they do any other members of the genus