Testing for Vertical Inequity in Property Tax Systems

Models for testing assessor performance have been widely discussed in the literature. Many have been used in practice. The purpose of this study are to evaluate the performance of existing models and to propose two new models. We find that existing models can be used correctly to test for inequity when their functional form is consistent with the pattern of the assessment-sales ratio data. Results from the application of different models show inconsistencies since the appropriate functional form may vary for different data sets. The new models have the ability to emulate the forms of the existing models as well as handle more complex relationships.

Student Perceptions Of The Online Classroom: An Update

In this paper, the authors compare perceptions of 2001-2002 undergraduate students toward online courses, with the attitudes of undergraduate students matriculating in 2005. Specifically, a questionnaire developed and used in a study during the period 2001-2002, in which there were eight hundred ninety-six (896) undergraduate students at two medium-sized southern universities, was again given to six hundred twenty-six (626) undergraduate students at these same two universities in 2005. The results suggest that students continue to have questions about the overall appeal of online courses, despite the fact that three to four years have elapsed. The results of this study should be of interest to university administrators, faculty members, and students who plan to offer, teach, or take online courses in the future. This information may be helpful to university administrators in deciding which types of courses at their universities might be offered online. Faculty who are considering teaching one or more online courses may find the results of this study helpful in structuring these online offerings. This research is also intended to give students a realistic expectation of what to anticipate from online courses, based upon information we have found and studies we have done

Faculty Perceptions Of Distance Education Courses: A Survey

This paper discusses the results of a study of the perceptions of a national sample of business faculty members from various business disciplines regarding distance (online) education and teaching distance education courses.  In the past few years, distance learning programs have become very popular, and the number of offerings continues to increase.  However, distance learning courses offer significant differences from the classic classroom environment.  The results of this study suggest that the offering of online courses in business is still in the early or developmental stages, and that only a small percentage of the respondents indicate that they would teach online courses in the future

Nanoparticle metrology of silica colloids and super-resolution studies using the ADOTA fluorophore

We describe how a new fluorescent dye, methyl ADOTA (N-methyl-azadioxatriangulenium tetrafluoroborate), is an improvement on dyes reported previously for measuring silica nanoparticle size in sols using the decay of fluorescence anisotropy. Me(thyl)-ADOTA possesses the unusual combination of having a red emission and a long fluorescence lifetime of ~ 20 ns, leaving it better-placed to reveal particle sizes at the upper end of the 1-10 nm measurement range. For stable LUDOX colloids, Me-ADOTA is shown to offer higher measurement precision in ≤ 1/30th of the measurement time required for dyes previously used. In measurement times of only ~ 20 mins nanoparticle radii for LUDOX SM-AS, AM and AS-40 of 4.6 ± 0.3 nm, 5.9 ± 0.2 nm and 11.1 ± 1.1 nm, are in good agreement with two of the manufacturer’s values of 3.5 nm, 6 nm and 11 nm respectively. Unlike the Si-ADOTA (N-(4-(triethoxysilylethyl)urea-phenyl-) ADOTA tetrafluoroborate) derivative containing a reactive trimetoxysilane group, Me-ADOTA is shown to not induce aggregation of colloidal silica. Measurements on nanoparticles growing in an acidic silica hydrogel at pH 0.94, prior to the gel time of ~ 50 hr, reveals an average nanoparticle size up to ~ 6.3 nm, significantly larger than the 4.5 nm reported previously. The difference is most certainly due to the longer fluorescence lifetime of Me-ADOTA (~ 20 ns) revealing the presence of larger particles. Studies of growing silica clusters in an alcogel of tetraethyl orthosilicate (TEOS) were able to resolve a monotonically increasing average radius of 1.42 ± 0.10 nm to 1.81 ± 0.14 nm over a period of 48 hr. We have also assessed a carboxylic acid derivative of ADOTA (N-(3-carboxypropylene)-ADOTA tetrafluoroborate - Acid-ADOTA) using dSTORM super-resolution microscopy. Although demonstrating high photochemical stability and blinking, its lower brightness and relative propensity to aggregate limits Acid-ADOTA’s use for dSTORM

Scaling Ecosystem Services to Reef Development : Effects of oyster density on nitrogen removal and reef community structure

Eighteen native oyster experimental reefs (16-m2 each) were restored using six oyster densities (0, 10, 25, 50, 100 and 250 adult oysters m-2) with three replicates of each density at each of two sites: one subtidal site in Onancock Creek, Virginia and one intertidal site in Hillcrest Oyster Sanctuary within The Nature Conservancy’s Virginia Coast Reserve. A science-based monitoring program explored quantitative relationships between structural and functional characteristics of these restored reefs. Structural parameters examined included oyster abundance, oyster size/biomass, surface shell volume, reef topographic complexity and sediment characteristics. Functional parameters included denitrification rates and macrofaunal abundance and biomass. Data were collected from the intertidal site during six sampling periods between April 2012 and July 2013 and from the subtidal site in April and June 2012. Relationships between reef structural parameters and functional parameters were complex and variable. As of July 2014, the intertidal reefs continue to serve as a platform for continued studies of the relationships between reef structural and functional characteristics

A new arenavirus in a cluster of fatal transplant-associated diseases

Three patients who received visceral-organ transplants from a single donor on the same day died of a febrile illness 4 to 6 weeks after transplantation. Culture, polymerase-chain-reaction (PCR) and serologic assays, and oligonucleotide microarray analysis for a wide range of infectious agents were not informative. We evaluated RNA obtained from the liver and kidney transplant recipients. Unbiased high-throughput sequencing was used to identify microbial sequences not found by means of other methods. The specificity of sequences for a new candidate pathogen was confirmed by means of culture and by means of PCR, immunohistochemical, and serologic analyses. High-throughput sequencing yielded 103,632 sequences, of which 14 represented an Old World arenavirus. Additional sequence analysis showed that this new arenavirus was related to lymphocytic choriomeningitis viruses. Specific PCR assays based on a unique sequence confirmed the presence of the virus in the kidneys, liver, blood, and cerebrospinal fluid of the recipients. Immunohistochemical analysis revealed arenavirus antigen in the liver and kidney transplants in the recipients. IgM and IgG antiviral antibodies were detected in the serum of the donor. Seroconversion was evident in serum specimens obtained from one recipient at two time points

A new arenavirus in a cluster of fatal transplant-associated diseases

Three patients who received visceral-organ transplants from a single donor on the same day died of a febrile illness 4 to 6 weeks after transplantation. Culture, polymerase-chain-reaction (PCR) and serologic assays, and oligonucleotide microarray analysis for a wide range of infectious agents were not informative. We evaluated RNA obtained from the liver and kidney transplant recipients. Unbiased high-throughput sequencing was used to identify microbial sequences not found by means of other methods. The specificity of sequences for a new candidate pathogen was confirmed by means of culture and by means of PCR, immunohistochemical, and serologic analyses. High-throughput sequencing yielded 103,632 sequences, of which 14 represented an Old World arenavirus. Additional sequence analysis showed that this new arenavirus was related to lymphocytic choriomeningitis viruses. Specific PCR assays based on a unique sequence confirmed the presence of the virus in the kidneys, liver, blood, and cerebrospinal fluid of the recipients. Immunohistochemical analysis revealed arenavirus antigen in the liver and kidney transplants in the recipients. IgM and IgG antiviral antibodies were detected in the serum of the donor. Seroconversion was evident in serum specimens obtained from one recipient at two time points

Modeling the Subsurface Structure of Sunspots

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic