Property Assessments and Information Asymmetry in Residential Real Estate

This paper presents a game theoretic model of property tax assessment that allows a tax appraiser to either choose a high or a low assessment. The owner either accepts or challenges this assessment. A ‘‘fixed effects’’ regression model is used to evaluate the differences in the assessed values of a sample of houses from Bexar County, Texas during 2000 and 2001. Where the owner of the house is identified as a state licensed property tax consultant, the assessed value, after adjusting for size, age, and other economic characteristics, ranged from a statistically robust 2.5% to 6.2% lower than neighboring houses.

Density functional theory in transition-metal chemistry: a self-consistent Hubbard U approach

Transition-metal centers are the active sites for many biological and inorganic chemical reactions. Notwithstanding this central importance, density-functional theory calculations based on generalized-gradient approximations often fail to describe energetics, multiplet structures, reaction barriers, and geometries around the active sites. We suggest here an alternative approach, derived from the Hubbard U correction to solid-state problems, that provides an excellent agreement with correlated-electron quantum chemistry calculations in test cases that range from the ground state of Fe$_2$ and Fe$_2^-$ to the addition-elimination of molecular hydrogen on FeO$^+$. The Hubbard U is determined with a novel self-consistent procedure based on a linear-response approach.Comment: 5 pages, 3 figures, Phys. Rev. Lett., in pres

Implementation of advanced matrix corrections for active interrogation of waste drums using the CTEN instrument

The combined thermal/epithermal neutron instrument (CTEN) was designed at Los Alamos to improve measurement accuracy and mitigate self shielding effects inherent in the differential dieaway technique (DDT). A major goal in this research effort has been the development of a calibration technique that incorporates recently developed matrix and self-shielding corrections using data generated from additional detectors and new acquisition techniques. A comprehensive data set containing both active and passive measurements was generated using 26 different matrices and comprising a total of 1,400 measurements. In all, 31 flux-and-matrix-dependent parameters, 24 positional parameters, two dieaway times, and a correlated ratio were determined from each of the over 1,400 measurements. A reduced list of matrix indicators, prioritized using the alternating conditional expectation (ACE) algorithm, was used to train a neural network using a generalized regression technique (GRNN) to determine matrix- and position-corrected calibration factors. This paper describes the experimental, analytical, and empirical techniques used to determine the corrected calibration factor for an unknown waste drum. Results from a range of cases are compared with those obtained using a mobile DDT instrument and traditional DDT algorithms

Influence of two different solid-liquid separation processes on the settling characteristics of swine effluent.

ABSTRACT: Solid-liquid separation (SLS) in swine manure treatment is an important step due to a substantial amount of organic and inorganic solids that can be removed from liquid wastewater. The aim of this study was to evaluate the efficiency of two mechanical separation processes (screw press and rotary screen) followed by settling and to analyze the composition of liquid fractions. In this sense, total solids (TS), volatile solids (VS), fixed solids (FS), total phosphorous (TP), total Kjeldahl nitrogen (TKN) and total organic carbon (TOC) were analyzed. By combining mechanical separation with settling, the average of TS, VS and FS removal was 75%, 80% and 69%, respectively. Phosphorus removal reached 86%, and TKN achieved a reduction up to 45%. There was no statistical difference among the results obtained using SLS by screw press and rotary screen. It was possible to conclude that SLS process with mechanical devices, followed by settling, generates a suitable effluent to be used on nitrification and denitrification process, producing an effluent with a C/N ratio of 2.6, and the solid fraction is useful to anaerobic digestion

Study of nitrogen consumption by nitrification process.

ABSTRACT: Biological processes are being applied to nitrogen removal from wastewater. The conventional process is based on nitrification followed by denitrification. In nitrification process the ammoniacal nitrogen is oxidized to nitrate and it is strongly influenced by availability of dissolved oxygen. In this context, kinetics studies are an alternative used to evaluate the microorganisms activity by defining substrate (NH3-N) consumption and the influence of others parameters, like oxygen and substrate. The present study aims to evaluate the ammonium consumption rate by nitrification process at three different ammonia concentrations (100, 200 and 300 mg NH3-N L -1 ) at air flow rates of 20, 30, 50, 100, 200 and 500 mLair min−1 L −1 reactor. The kinetics were made by batch tests in an EGSB reactor at temperature of 25ºC for 2h30min. It was visualized that with 100 and 200 mg N-NH3 L - ¹ the substrate concentration was fully consumed. However, at the substrate concentration of 300 mg NH3-N L - ¹ an increase of substrate consumption was observed but ammonia was not entirely consumed. Furthermore, for the three initial ammonia concentrations, the behavior of substrate consumption was similar in function of air flow rate. Additionally, it was possible to conclude that as the supply of oxygen increased, the nitrogen ammoniacal consumption rate also increased

Lump correction and identification in the combined thermal/epithermal neutron (CTEN) method

The authors present a model for self shielding in lumps of fissile material in active-neutron assays. The model combines the formula for self-attenuation of gamma-ray in lumpy sources with the multi-group analysis techniques used in neutron transport calculations. Models for thin foils and for spheres are examined in terms of error multiplication in determining lump corrections and the basic accuracy of the model

Transcriptional regulation of the urokinase receptor (u-PAR) - A central molecule of invasion and metastasis

The phenomenon of tumor-associated proteolysis has been acknowledged as a decisive step in the progression of cancer. This short review focuses on the urokinase receptor (u-PAR), a central molecule involved in tumor-associated invasion and metastasis, and summarizes the transcriptional regulation of u-PAR. The urokinase receptor (u-PAR) is a heavily glycosylated cell surface protein and binds the serine protease urokinase specifically and with high affinity. It consists of three similar cysteine-rich repeats and is anchored to the cell membrane via a GPI-anchor. The u-PAR gene comprises 7 exons and is located on chromosome 19q13. Transcriptional activation of the u-PAR promoter region can be induced by binding of transcription factors (Sp1, AP-1, AP-2, NF-kappaB). One current study gives an example for transcriptional downregulation of u-PAR through a PEA3/ets transcriptional silencing element. Knowledge of the molecular regulation of this molecule in tumor cells could be very important for diagnosis and therapy in the near future