Surgery on SL~×En\widetilde{\Bbb{SL}}\times\Bbb{E}^n-manifolds

We show that although closed $\widetilde{\Bbb{SL}}\times\Bbb{E}^n$-manifolds do not admit metrics of nonpositive sectional curvature, the arguments of Farrell and Jones can be extended to show that such manifolds are topologically rigid, if $n\geq2$.Comment: 7 pages, AMS-LaTeX file, To appear in the Canadian Mathematical Bulletin

Life Satisfaction: Measurement Invariance and Correlations with Adolescent Adjustment

Background Low life satisfaction during adolescence has been associated with adjustment problems. There are few well-validated measures available to assess adolescents’ life-satisfaction. The purpose of this study was to investigate the structure of the Life Satisfaction Scale, evaluate its measurement invariance across sex and race/ethnicity, and investigate its associations with related constructs. Methods Participants were 3,340 adolescents from rural middle schools in Florida. Half the participants were female, 51% were White, 15% were Black, and 22% were Latinx. Adolescents completed the Life Satisfaction Scale, the Children’s Report of Exposure to Violence scale, and the Problem Behavior Frequency Scale. Results Confirmatory factor analysis found support for a single factor representing overall life satisfaction, and strong measurement invariance across race, but not across sex. There were significant differences in item thresholds such that girls at the same level of life satisfaction as boys, were more likely to endorse higher responses to items assessing satisfaction with school, with themselves, and with their friendships. Life satisfaction had significant negative correlations with violence exposure, problem behavior, and peer pressure for drug use. Conclusion Findings suggest that the Life Satisfaction Scale may be suitable for assessing life satisfaction across different groups of adolescents. Examining sex differences must be done cautiously as life satisfaction may have different meanings to boys and girls. The inverse correlations between life satisfaction, violence exposure and problem behavior across groups highlights the importance of developing sound measures to assess this important construct and determine how it relates to youth adjustment.https://scholarscompass.vcu.edu/gradposters/1076/thumbnail.jp

Superorbital Period in the High Mass X-ray Binary 2S 0114+650

We report the detection of a superorbital period in the high-mass X-ray binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously reported neutron star spin period of 2.7 h and the binary orbital period of 11.6 d. It is unclear if the superorbital period can be ascribed to the precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript expanded to include discussion of evolution of periods, and hardness ratio variability. Number of figures increased from 5 to 9. Accepted for publication 19th December 200

A synoptic description of coal basins via image processing

An existing image processing system is adapted to describe the geologic attributes of a regional coal basin. This scheme handles a map as if it were a matrix, in contrast to more conventional approaches which represent map information in terms of linked polygons. The utility of the image processing approach is demonstrated by a multiattribute analysis of the Herrin No. 6 coal seam in Illinois. Findings include the location of a resource and estimation of tonnage corresponding to constraints on seam thickness, overburden, and Btu value, which are illustrative of the need for new mining technology

The fibered isomorphism conjecture for complex manifolds

In this paper we show that the fibered isomorphism conjecture of Farrell and Jones corresponding to the stable topological pseudoisotopy functor is true for the fundamental groups of a large class of complex manifolds. A consequence of this result is that the Whitehead group, reduced projective class groups and the negative K-groups of the fundamental group of these manifolds vanish whenever the fundamental group is torsion free. We also prove the same results for a class of real manifolds.Comment: accepted for publication in Acta Mathematica Sinica, English Serie

Reflections on the Role of Consultation in the Delivery of Effective Educational Psychology Services

For many years educational and school psychologists from all over the world have emphasised the importance of consultation as a key approach to delivering effective services. However, there is a considerable body of literature indicating that the approach has not been widely adopted by educational psychologists in the UK and elsewhere. This paper considers some interconnected factors that might explain why educational psychologists may be reluctant to wholeheartedly embrace this approach. First, it considers the possibility that educational psychologists, who may claim to work in a ‘traditional’ way, are in fact using consultation regularly in their everyday practice, although not in the way that it is often defined in the literature. Second, the influence of the history of the profession, in which educational psychologists were described as being experts in psychometric assessment, may be acting as a barrier to adopting alternative practices. Third, unintentionally perhaps, the efforts of professional associations to promote educational and school psychology may reinforce the importance of maintaining traditional practices based on individual psychometric assessments of children thought to have special educational needs and disabilities. Finally the paper discusses the skills and competencies needed to work effectively as a school-based consultant and suggests that these pose particular challenges to new entrants to the profession who wish to work in this way. The paper concludes by suggesting that debates about the relative importance of individual work versus consultation present a false dichotomy. Both roles are central to the delivery of effective psychological services. Educational psychologists need to have the necessary skills and confidence in all areas of professional practice, being able to strike the right balance between the two approaches and sensitive to the situations where each is likely to be effective in dealing with the range of problems with which they are presented

The isomorphism conjecture for 3-manifold groups and K-theory of virtually poly-surface groups

This article has two purposes. In \cite{R3} (math.KT/0405211) we showed that the FIC (Fibered Isomorphism Conjecture for pseudoisotopy functor) for a particular class of 3-manifolds (we denoted this class by \cal C) is the key to prove the FIC for 3-manifold groups in general. And we proved the FIC for the fundamental groups of members of a subclass of \cal C. This result was obtained by showing that the double of any member of this subclass is either Seifert fibered or supports a nonpositively curved metric. In this article we prove that for any M in {\cal C} there is a closed 3-manifold P such that either P is Seifert fibered or is a nonpositively curved 3-manifold and \pi_1(M) is a subgroup of \pi_1(P). As a consequence this proves that the FIC is true for any B-group (see definition 3.2 in \cite{R3}). Therefore, the FIC is true for any Haken 3-manifold group and hence for any 3-manifold group (using the reduction theorem of \cite{R3}) provided we assume the Geometrization conjecture. The above result also proves the FIC for a class of 4-manifold groups (see \cite{R2}(math.GT/0209119)). The second aspect of this article is to relax a condition in the definition of strongly poly-surface group (\cite{R1} (math.GT/0209118)) and define a new class of groups (we call them {\it weak strongly poly-surface} groups). Then using the above result we prove the FIC for any virtually weak strongly poly-surface group. We also give a corrected proof of the main lemma of \cite{R1}.Comment: 12 pages, AMS Latex file, 1 figure, final version. accepted for publication in K-theor

Binscatter Regressions

We introduce the \texttt{Stata} (and \texttt{R}) package \textsf{Binsreg}, which implements the binscatter methods developed in \citet*{Cattaneo-Crump-Farrell-Feng_2019_Binscatter}. The package includes the commands \texttt{binsreg}, \texttt{binsregtest}, and \texttt{binsregselect}. The first command (\texttt{binsreg}) implements binscatter for the regression function and its derivatives, offering several point estimation, confidence intervals and confidence bands procedures, with particular focus on constructing binned scatter plots. The second command (\texttt{binsregtest}) implements hypothesis testing procedures for parametric specification and for nonparametric shape restrictions of the unknown regression function. Finally, the third command (\texttt{binsregselect}) implements data-driven number of bins selectors for binscatter implementation using either quantile-spaced or evenly-spaced binning/partitioning. All the commands allow for covariate adjustment, smoothness restrictions, weighting and clustering, among other features. A companion \texttt{R} package with the same capabilities is also available

A Multicoloured View of 2S 0114+650

We report the results of radio and X-ray observations of the high mass X-ray binary 2S 0114+650, made with the Giant Meterwave Radio Telescope and the Rossi X-ray Timing Explorer respectively. No emission was detected at radio wavelengths. The neutral hydrogen column density was found to vary over the orbital period, while no variability over the the super-orbital period was observed. We discuss the causes of the observed relationships and the implications for the underlying mechanisms.Comment: 4 pages, 2 figures; to appear in proceedings for "The multicoloured landscape of compact objects and their explosive progenitors", Cefalu, Sicily, 2006 June 11-24, AIP, submitte