On Estimating Marginal Tax Rates and Tax Progressivities for U.S. States

This research presents a simple procedure for improving state-specific estimates of marginal tax rates (MTR’s). Most research employing MTR’s follows a procedure developed by Koester and Kormendi (K&K, 1987). Unfortunately, the time-invariant nature of the K&K estimates precludes their use as explanatory variables in panel data studies. Furthermore, their estimates are not based on statutory tax parameters. In contrast, our procedure produces timevarying estimates of MTR’s that are directly related to observed changes in statutory tax parameters. Using comprehensive data on state tax policy parameters, our procedure produces state-specific MTR’s estimates for all 50 states over the years 1977-2004. We compare our refined MTR’s to alternative estimates and evaluate implications for estimating tax progressivity for US states.State tax revenues; Marginal tax rates; Tax burden; Tax progressivity; Economic growth.

Polynomials inducing the zero function on local rings

For a Noetherian local ring (R, m) having a finite residue field of cardinality q, we study the connections between the ideal N (R) of R[x], which is the set of polynomials that vanish on R, and the ideal N(m), the polynomials that vanish on m, using polynomials of the form (formula presented) where c1,…, cq is a set of representatives of the residue classes of m. In particular, when R is Henselian we show that a generating set for N (R) may be obtained from a generating set for N (m) by composing with π(x)

Using Statistical and Judgmental Reviews to Identify and Interpret Translation Differential Item Functioning

The purpose of this study was to evaluate the equivalence of two translated tests using statistical and judgmental methods. Performance differences for a large random sample of English- and French-speaking examinees were compared on a grade 6 mathematics and social studies provincial achievement test. Items displaying differential item functioning (DIF) were flagged using three popular statistical methods—ManteTHaenszel, Simultaneous Item Bias Test, and logistic regression—and the substantive meaning of these items was studied by comparing the back-translated form with the original English version. The items flagged by the three statistical procedures were relatively consistent, but not identical across the two tests. The correlation between the DIF effect size measures were also strong, but far from perfect, suggesting that two procedures should be used to screen items for translation DIF. To identify the DIF items with translation differences, the French items were back-translated into English and compared with the original English items by three reviewers. Two of seven and six of 26 DIF items in mathematics and social studies respectively were judged to be nonequivalent across language forms due to differences introduced in the translation process. There were no apparent translation differences for the remaining items, revealing the necessity for further research on the sources of translation differential item functioning. Results from this study provide researchers and practitioners with a better understanding of how three popular DIF statistical methods compare and contrast. The results also demonstrate how statistical methods inform substantive reviews intended to identify items with translation differences.Le but de cette étude était d'évaluer l'équivalence de deux examens traduits avec des méthodes basées sur les statistiques et d'autres reposant sur le jugement. On a comparé les différences dans la performance d'un grand échantillon aléatoire de sujets anglophones et francophones qui avaient complété des examen provinciaux de sixième année en mathématiques et en études sociales. Les items démontrant une divergence par rapport aux autres (differential item functioning - DIF) ont été marqués d'un indicateur dans le contexte de trois méthodes statistiques bien connues - Mantel-Haenszel, Simultaneous Item Bias Test et la régression logistique. La signification de fond de ces items a été étudiée en comparant la version traduite de l'examen avec l'original en anglais. Les items marqués par les trois procédures statistiques étaient relativement constants mais pas identiques d'une version à l'autre. Alors que la corrélation entre les mesures de l'effet DIF étaient aussi forte, elle était loin d'être parfaite, ce qui suggère que l'on devrait avoir recours à deux procédures dans le dépistage du DIF en traduction. Pour identifier les items DIF présentant des différences en traduction, trois réviseurs ont comparé les items français retraduits en anglais avec les originaux en anglais. Ceux-ci ont jugé que deux sur sept items en mathématiques et six sur vingt-six items en études sociales n'étaient pas équivalents d'une langue à l'autre à cause des différences introduites par le processus de traduction. Les autres items ne présentaient pas de différences apparentes de traduction, ce qui révèle le besoin de poursuivre la recherche sur les sources du DIF en traduction. Les résultats de cette étude aideront les chercheurs et les praticiens à mieux comprendre les similarités et les différences entres trois méthodes statistiques DIF souvent employées. De plus, ils démontrent comment les méthodes statistiques contribuent aux études de signification dont le but est l'identification des items présentant des différences de traduction

The geometry of reaction norms yields insights on classical fitness functions for Great Lakes salmon.

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions-intrinsic rate of natural increase r, net reproductive rate R0, and reproductive value Vx-for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior. In one's efforts to understand an organism's behavior and to develop effective conservation and management policies, the choice of fitness function matters. The central ingredient of our approach is the maturation reaction norm (MRN), which describes how optimal age and size at maturation vary with growth rate or mortality rate. We develop a practical geometric construction of MRNs that allows us to include different growth functions (linear growth and nonlinear von Bertalanffy growth in length) and develop two-dimensional MRNs useful for quantifying growth-mortality trade-offs. We relate our approach to Beverton-Holt life history invariants and to the Stearns-Koella categorization of MRNs. We conclude with a detailed discussion of life history parameters for Great Lakes Chinook Salmon and demonstrate that age and size at maturity are consistent with predictions using R0 (but not r or Vx) as the underlying fitness function

Differential Validity and Utility of Successive and Simultaneous Approaches to the Development of Equivalent Achievement Tests in French and English

Described in this article are the first three activities of a research program designed to assess the differential validity and utility of successive and simultaneous approaches to the development of equivalent achievement tests in the French and English languages. Two teams of multilingual/multicultural French-English teachers used the simultaneous approach to develop 70 items respectively for mathematics and social studies at the grade 9 level. The evidence gained from the pilot study suggests that the issue of differential item performance attributable to translation differences appears to be confounded by the presence of socioeconomic differences between the two groups of students. Consequently, the next activities of this research will be directed toward disentangling these two issues to obtain a clearer view of the efficacy of the simultaneous method in reducing differential group performance and enhancing linguistic and cultural decentering

How Captain Amerika uses neural networks to fight crime

Artificial neural network models can make amazing computations. These models are explained along with their application in problems associated with fighting crime. Specific problems addressed are identification of people using face recognition, speaker identification, and fingerprint and handwriting analysis (biometric authentication)

Fetal liver blood flow distribution: role in human developmental strategy to prioritize fat deposition versus brain development

Among primates, human neonates have the largest brains but also the highest proportion of body fat. If placental nutrient supply is limited, the fetus faces a dilemma: should resources be allocated to brain growth, or to fat deposition for use as a potential postnatal energy reserve? We hypothesised that resolving this dilemma operates at the level of umbilical blood distribution entering the fetal liver. In 381 uncomplicated pregnancies in third trimester, we measured blood flow perfusing the fetal liver, or bypassing it via the ductus venosus to supply the brain and heart using ultrasound techniques. Across the range of fetal growth and independent of the mother's adiposity and parity, greater liver blood flow was associated with greater offspring fat mass measured by dual-energy X-ray absorptiometry, both in the infant at birth (r = 0.43, P<0.001) and at age 4 years (r = 0.16, P = 0.02). In contrast, smaller placentas less able to meet fetal demand for essential nutrients were associated with a brain-sparing flow pattern (r = 0.17, p = 0.02). This flow pattern was also associated with a higher degree of shunting through ductus venosus (P = 0.04). We propose that humans evolved a developmental strategy to prioritize nutrient allocation for prenatal fat deposition when the supply of conditionally essential nutrients requiring hepatic inter-conversion is limited, switching resource allocation to favour the brain if the supply of essential nutrients is limited. Facilitated placental transfer mechanisms for glucose and other nutrients evolved in environments less affluent than those now prevalent in developed populations, and we propose that in circumstances of maternal adiposity and nutrient excess these mechanisms now also lead to prenatal fat deposition. Prenatal developmental influences play important roles in the human propensity to deposit fa

Using WebGIS to Develop a Spatial Bibliography for Organizing, Mapping, and Disseminating Research Information: A Case Study of Quaking Aspen

On the Ground • Spatial data is valuable to researchers for locating studies that occur in a particular area of interest, or one with similar attributes. • Without a standard in publishing protocol, spatial data largely goes unreported, or is difficult to find without searching the publication. • Assigning location data and displaying points on a public web map makes locating publications based on spatial location possible