Theoretical Setting of Inner Reversible Quantum Measurements

We show that any unitary transformation performed on the quantum state of a closed quantum system, describes an inner, reversible, generalized quantum measurement. We also show that under some specific conditions it is possible to perform a unitary transformation on the state of the closed quantum system by means of a collection of generalized measurement operators. In particular, given a complete set of orthogonal projectors, it is possible to implement a reversible quantum measurement that preserves the probabilities. In this context, we introduce the concept of "Truth-Observable", which is the physical counterpart of an inner logical truth.Comment: 11 pages. More concise, shortened version for submission to journal. References adde

Day-night asymmetries of low-energy electrons in Saturn's inner magnetosphere

We examine the day-night asymmetry of near-equatorial low energy (12-100 eV) electron fluxes measured by Cassini from July 1, 2004 through April 1, 2010. This energy range is also known to be associated with interchange injections. The electrons are separated into field-aligned (0 degrees to 20 degrees and 160 degrees to 180 degrees) pitch angles and trapped (70 degrees to 110 degrees) pitch angles. There is a stronger day-night asymmetry for the trapped than the field-aligned electrons, but both show enhanced energy fluxes on the nightside relative to the dayside. The dayside electron fluxes decrease sharply at an L-shell of 8, while the nightside electrons exhibit a slow decline in to L = 5. Our finding, along with previous research of high energy electrons, shows that this asymmetry is energy independent. This suggests that interchange injections are stronger, and therefore penetrate deeper into the magnetosphere, on the nightside

Self-reported pregnancy exposures and placental DNA methylation in the MARBLES prospective autism sibling study.

Human placenta is a fetal-derived tissue that offers a unique sample of epigenetic and environmental exposures present in utero. In the MARBLES prospective pregnancy study of high-risk younger siblings of children with autism spectrum disorder (ASD), pregnancy and environmental factors collected by maternal interviews were examined as predictors of placental DNA methylation, including partially methylated domains (PMDs), an embryonic feature of the placental methylome. DNA methylation data from MethylC-seq analysis of 47 placentas of children clinically diagnosed at 3 years with ASD or typical development using standardized assessments were examined in relation to: child's gestational age, birth-weight, and diagnosis; maternal pre-pregnancy body mass index, smoking, education, parity, height, prenatal vitamin and folate intake; home ownership; pesticides professionally applied to lawns or gardens or inside homes, pet flea/tick pouches, collars, or soaps/shampoos used in the 3 months prior to or during pregnancy. Sequencing run, order, and coverage, and child race and sex were considered as potential confounders. Akaike information criterion was used to select the most parsimonious among candidate models. Final prediction models used sandwich estimators to produce homoscadisticity-robust estimates of the 95% confidence interval (CI) and P-values controlled the false discovery rate at 5%. The strongest, most robust associations were between pesticides professionally applied outside the home and higher average methylation over PMDs [0.45 (95% CI 0.17, 0.72), P = 0.03] and a reduced proportion of the genome in PMDs [-0.42 (95% CI - 0.67 to -0.17), P = 0.03]. Pesticide exposures could alter placental DNA methylation more than other factors

Hard X-ray variability of the black-hole candidate GRO J0422+32 during its 1992 outburst

We have studied the hard X-ray variability of the soft X-ray transient GRO J0422+32 with BATSE in the 20-100 keV energy band. Our analysis covers 180 days following the first X-ray detection of the source on 1992 August 5, fully covering its primary and secondary X-ray outburst. We computed power density spectra (PDSs) in the 20-50, 50-100, and 20-100 keV energy bands, in the frequency interval 0.002-0.488 Hz. The PDSs of GRO J0422+32 are approximately flat up to a break frequency, and decay as a power law above, with index ~1. The canonical anticorrelation between the break frequency and the power density at the break, observed in Cyg X-1 and other BHCs in the low state, is not observed in the PDSs of GRO J0422+32. We compare our results with those of similar variability studies of Cyg X-1. The relation between the spectral slope and the amplitude of the X-ray variations of GRO J0422+32 is similar to that of Cyg X-1; however, the relation between the hard X-ray flux and the amplitude of its variation is opposite to what has been found in Cyg X-1. Phase lags between the X-ray flux variations of GRO J0422+32 at high and low photon energies, could only be derived during the first 30 days of its outburst. During this period, the variations in the 50-100 keV lag those in the 20-50 keV energy band by an approximately constant phase difference of 0.039(3) rad in the frequency interval 0.02-0.20 Hz.Comment: 33 pages, including 14 postscript figures, AASTEX. To appear in ApJ 1999, March 1, vol. 513 #

Many Disease-Associated Variants of hTERT Retain High Telomerase Enzymatic Activity

Mutations in the gene for telomerase reverse transcriptase (hTERT) are associated with diseases including dyskeratosis congenita, aplastic anemia, pulmonary fibrosis and cancer. Understanding the molecular basis of these telomerase-associated diseases requires dependable quantitative measurements of telomerase enzyme activity. Furthermore, recent findings that the human POT1-TPP1 chromosome end-binding protein complex stimulates telomerase activity and processivity provide incentive for testing variant telomerases in the presence of these factors. In the present work, we compare multiple disease-associated hTERT variants reconstituted with the RNA subunit hTR in two systems (rabbit reticulocyte lysates and human cell lines) with respect to telomerase enzymatic activity, processivity and activation by telomere proteins. Surprisingly, many of the previously reported disease-associated hTERTalleles give near-normal telomerase enzyme activity. It is possible that a small deficit in telomerase activity is sufficient to cause telomere shortening over many years. Alternatively, mutations may perturb functions such as the recruitment of telomerase to telomeres, which are essential in vivo but not revealed by simple enzyme assays

Correlation Between BATSE Hard X-ray Spectral and Timing Properties of Cygnus X-1

We have analyzed approximately 1100 days of Cygnus X-1 hard X-ray data obtained with BATSE to study its rapid variability. We find for the first time correlations between the slope of the spectrum and the hard X-ray intensity, and between the spectral slope and the amplitude of the rapid variations of the hard X-ray flux. We compare our results with expectations from current theories of accretion onto black holes.Comment: 17 pages, 3 Postscript figures, uses aasms4.sty. Accepted for publication in Astrophysical Journal Letter

A Bevalac Calibration of a Scintillating Optical Fiber Hodoscope for Possible use on the Advanced Composition Explorer

As part of instrument definition activities for the Advanced Composition Explorer (ACE) we are evaluating a hodoscope comprised of scintillating fibers for possible use in the Cosmic Ray Isotope Spectrometer (CRIS). The hodoscope would determine the trajectories of individual cosmic ray nuclei which stop in the silicon solid state telescopes in CRIS. We report a preliminary analysis of data from a Dec., 1990 Bevalac calibration of a CRIS test model which consisted of a scintillating fiber hodosccpe, utilizing 200mm, square cross section scintillating fibers, and silicon detectors for dE/dx-Erot measurements. The positional resolution obtained in our preliminary data analysis is -60μm for angles from 0-30°. The detection efficiency for iron and silicon nuclei was determined to be >99% for beam angles of ≥ 20°

Hard X-ray lags in GRO J1719-24

We have used the Fourier cross spectra of GRO J1719-24, as obtained with BATSE, to estimate the phase lags between the X-ray flux variations in the 20--50 and 50--100 keV energy bands as a function of Fourier frequency in the interval 0.002--0.488 Hz. Our analysis covers the entire ~80 day X-ray outburst of this black-hole candidate, following the first X-ray detection on 1993 September 25. The X-ray variations in the 50--100 keV band lag those in the 20--50 keV energy band by an approximately constant phase difference of 0.072 +/- 0.010 rad in the frequency interval 0.02--0.20 Hz. The peak phase lags in the interval 0.02--0.20 Hz are about twice those of Cyg X-1 and GRO J0422+32.These results are consistent with models for Comptonization regions composed of extended non-uniform clouds around the central source.Comment: 10 pages, including 4 postscript figures, AASTEX. Accepted for publication by Ap