Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

APOE ɛ4 exacerbates age-dependent deficits in cortical microstructure

The apolipoprotein E ɛ4 allele is the primary genetic risk factor for the sporadic type of Alzheimer’s disease. However, the mechanisms by which apolipoprotein E ɛ4 are associated with neurodegeneration are still poorly understood. We applied the Neurite Orientation Dispersion Model to characterize the effects of apolipoprotein ɛ4 and its interactions with age and education on cortical microstructure in cognitively normal individuals. Data from 1954 participants were included from the PREVENT-Dementia and ALFA (ALzheimer and FAmilies) studies (mean age = 57, 1197 non-carriers and 757 apolipoprotein E ɛ4 carriers). Structural MRI datasets were processed with FreeSurfer v7.2. The Microstructure Diffusion Toolbox was used to derive Orientation Dispersion Index maps from diffusion MRI datasets. Primary analyses were focused on (i) the main effects of apolipoprotein E ɛ4, and (ii) the interactions of apolipoprotein E ɛ4 with age and education on lobar and vertex-wise Orientation Dispersion Index and implemented using Permutation Analysis of Linear Models. There were apolipoprotein E ɛ4 × age interactions in the temporo-parietal and frontal lobes, indicating steeper age-dependent Orientation Dispersion Index changes in apolipoprotein E ɛ4 carriers. Steeper age-related Orientation Dispersion Index declines were observed among apolipoprotein E ɛ4 carriers with lower years of education. We demonstrated that apolipoprotein E ɛ4 worsened age-related Orientation Dispersion Index decreases in brain regions typically associated with atrophy patterns of Alzheimer’s disease. This finding also suggests that apolipoprotein E ɛ4 may hasten the onset age of dementia by accelerating age-dependent reductions in cortical Orientation Dispersion Index

Influence Of Multiphase Flow In Well Test Analysis Of Nonflowing Wells

This work considers the influence of multiphase flow (oil and gas) in well testing analysis of non-flowing wells: For example, Drill Stem Test (DST) and Slug Test. The problem is solved by a two-dimensional (r-z), variable bubble-point, black oil simulator that incorporates the typical DST inner boundary condition. Initially, the oil in the reservoir is in equilibrium condition at the initial reservoir pressure which is considered greater or equal to the initial oil bubble-point pressure. A sequence of flow and/or buildup periods can be imposed at the reservoir sandface to simulate a non-flowing well test condition. Inertial, friction, and multiphase flow effects in the wellbore are neglected. Comparisons with analytical methods (developed for single phase flow of a fluid of small and constant compressibility) traditionally used to obtaining reservoir parameters (eg., transmissibility) are made to determine how good or bad these methods are in the presence of more than one phase flowing in the porous medium. During flow periods significant discrepancies are obtained, whereas in buildup flow periods these discrepancies are less significative. Explanation to these multiphase flow effects on the determination of reservoir parameters are given in detail, and justify why, usually, reservoir parameters obtained from flow tests do not match results obtained from build up periods in well test analysis.Omega61162