TopReX generator (version~3.25). Short manual

This is the manual of the specialized event generator TopReX 3.25. The generator provides the simulation of several important processes in pp and p pbar collisions, not implemented in PYTHIA (yet). Some of these processes include t-quarks whose spin polarizations are taken into account in the subsequent decay of the t-quarks. Several non-SM top quark decay channels are included, too. All calculated subprocesses can be accessed from PYTHIA as external processes. In addition, TopReX can be used as stand alone event generator, providing partonic final states before showering. In this mode the control of the event generation is taken by TopReX itself. A few simple examples of main routines, which show how to use TopReX in the different modes are discussed.Comment: 12 pages, 4 figures, LaTe

Extending an Effective Classroom-Based Math Board Game Intervention to Preschoolers’ Homes

The preschool years are a critical time for math development. Unfortunately, children from low-income backgrounds often enter kindergarten with lower math skills than middle-income peers, perhaps due to less math exposure at home. Few home-based math interventions are available for preschool age children; those that do exist are costly and difficult to implement. Interventions conducted in children’s schools using linear numeric board games developed by researchers have been particularly successful with low-income preschool children. Researchers have suggested they may be adapted for home-use by using commercially available board games, such as Chutes and Ladders, and teaching parents how to play. The two studies described in this paper explored the effectiveness of using Chutes and Ladders with a specialized counting procedure with Head Start families. Implementation proved to be challenging and children did not improve as much as in previous classroom-based interventions

Note and Comment

Wilgus: Payment of Dividends Out of Capital of Corporations and the Nature of Treasury Stock; Wilgus: Duty of a Managing Director of a Corporation to an Individual Shareholder; Williams: Impairing Obligation of Contract with Foreign Corporations; Dodds: May a Legislature Pass an Act Allowing Actual Expenses to Circuit Judges Whose Salaries are Fixed by the State Constitution?; Sonnenschein: What Constitutes a Waiver by Implication of the Privilege of Confidential Communications Between Attorney and Clien

Ductus venosus blood flow velocity characteristics of fetuses with single umbilical artery

Objectives: Sonographic Doppler evaluation of the fetal ductus venosus has been proved to be useful in the evaluation of fetal cardiac function. The aim of this study was to investigate the ductus venosus blood flow profile in fetuses with single umbilical artery and to correlate it with the umbilical cord morphology. Methods: Fetuses at > 20 weeks' gestation with single umbilical artery who were otherwise healthy were consecutively enrolled into the study. The sonographic examination included evaluation of the following Doppler parameters: umbilical artery resistance index, maximum blood flow velocity of the ductus venosus during ventricular systole (S-peak) and atrial contraction (A-wave), ductus venosus time-averaged maximum velocity (TAMXV), and pulsatility index for veins (PIV). The cross-sectional area of the umbilical cord and its vessels were measured in all cases. The Doppler and morphometric values obtained were plotted on reference ranges. Results: A total of 88 fetuses with single umbilical artery were scanned during the study period. Of these 52 met the inclusion criteria. The S-peak velocity, A-wave velocity, and TAMXV were below the 5th centile for gestational age in 57.7%, 59.6%, and 57.7% of cases, respectively. The PIV was within the normal range in 80.1% of cases. The umbilical vein cross-sectional area of fetuses with single umbilical artery was above the 95th centile for gestational age in 34.6% cases. Conclusions: The ductus venosus blood flow pattern is different in fetuses with single umbilical artery from that in those with a three-vessel cord. This difference may be caused in part by the particular morphology of umbilical cords with a single artery. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd

Resonance ionization spectroscopy of thorium isotopes - towards a laser spectroscopic identification of the low-lying 7.6 eV isomer of Th-229

In-source resonance ionization spectroscopy was used to identify an efficient and selective three step excitation/ionization scheme of thorium, suitable for titanium:sapphire (Ti:sa) lasers. The measurements were carried out in preparation of laser spectroscopic investigations for an identification of the low-lying Th-229m isomer predicted at 7.6 +- 0.5 eV above the nuclear ground state. Using a sample of Th-232, a multitude of optical transitions leading to over 20 previously unknown intermediate states of even parity as well as numerous high-lying odd parity auto-ionizing states were identified. Level energies were determined with an accuracy of 0.06 cm-1 for intermediate and 0.15 cm-1 for auto-ionizing states. Using different excitation pathways an assignment of total angular momenta for several energy levels was possible. One particularly efficient ionization scheme of thorium, exhibiting saturation in all three optical transitions, was studied in detail. For all three levels in this scheme, the isotope shifts of the isotopes Th-228, Th-229, and Th-230 relative to Th-232 were measured. An overall efficiency including ionization, transport and detection of 0.6 was determined, which was predominantly limited by the transmission of the mass spectrometer ion optics

Polynomials, Riemann surfaces, and reconstructing missing-energy events

We consider the problem of reconstructing energies, momenta, and masses in collider events with missing energy, along with the complications introduced by combinatorial ambiguities and measurement errors. Typically, one reconstructs more than one value and we show how the wrong values may be correlated with the right ones. The problem has a natural formulation in terms of the theory of Riemann surfaces. We discuss examples including top quark decays in the Standard Model (relevant for top quark mass measurements and tests of spin correlation), cascade decays in models of new physics containing dark matter candidates, decays of third-generation leptoquarks in composite models of electroweak symmetry breaking, and Higgs boson decay into two tau leptons.Comment: 28 pages, 6 figures; version accepted for publication, with discussion of Higgs to tau tau deca

The E-SCREEN assay as a tool to identify estrogens: an update on estrogenic environmental pollutants.

Estrogens are defined by their ability to induce the proliferation of cells of the female genital tract. The wide chemical diversity of estrogenic compounds precludes an accurate prediction of estrogenic activity on the basis of chemical structure. Rodent bioassays are not suited for the large-scale screening of chemicals before their release into the environment because of their cost, complexity, and ethical concerns. The E-SCREEN assay was developed to assess the estrogenicity of environmental chemicals using the proliferative effect of estrogens on their target cells as an end point. This quantitative assay compares the cell number achieved by similar inocula of MCF-7 cells in the absence of estrogens (negative control) and in the presence of 17 beta-estradiol (positive control) and a range of concentrations of chemicals suspected to be estrogenic. Among the compounds tested, several "new" estrogens were found; alkylphenols, phthalates, some PCB congeners and hydroxylated PCBs, and the insecticides dieldrin, endosulfan, and toxaphene were estrogenic by the E-SCREEN assay. In addition, these compounds competed with estradiol for binding to the estrogen receptor and increased the levels of progesterone receptor and pS2 in MCF-7 cells, as expected from estrogen mimics. Recombinant human growth factors (bFGF, EGF, IGF-1) and insulin did not increase in cell yields. The aims of the work summarized in this paper were a) to validate the E-SCREEN assay; b) to screen a variety of chemicals present in the environment to identify those that may be causing reproductive effects in wildlife and humans; c) to assess whether environmental estrogens may act cumulatively; and finally d) to discuss the reliability of this and other assays to screen chemicals for their estrogenicity before they are released into the environment