1,171 research outputs found
CP Tagged Decays at SuperBaBar
We explore the possibility of measuring the CKM parameter gamma using CP
tagged decays at a very high luminosity e+e- B Factory. A new collider capable
of integrating as much as 10 inverse attobarns per year is being discussed as a
possible future for SLAC beyond the current PEP-II program, and could also be
in the future of KEK. In two years of operation, it could be possible for a
successor to BaBar or Belle to accumulate a sample of one million CP tagged B
decays. We find that a theoretically clean extraction of gamma with uncertainty
less than 5 degrees may be achievable in the analysis of such a data set.Comment: 14 pages, 4 figures; minimal revisions for version to appear in
Physical Review D, all formulas and conclusions unchange
Distinguishing Latent from Active Mycobacterium tuberculosis Infection Using Elispot Assays: Looking Beyond Interferon-gamma
Mycobacterium tuberculosis (MTB) is a global heath epidemic, its threat amplified by HIV infection and the emergence of multidrug-resistant tuberculosis (MDR-TB). Interferon (IFN)-gamma release assays (IGRAs) have improved the accuracy of detection of MTB exposure in some subject groups as compared to the Tuberculin Skin Test (TST). However, as IFN-gamma is produced by both fully rested and more recently activated populations of memory T cells, it is not surprising that the measurement of this cytokine alone cannot accurately distinguish Latent TB Infected (LTBI) subjects from those with active (infectious) disease. Accurate and rapid diagnosis of infectious individuals would allow medication to be properly allocated and other actions taken to more effectively curtail MTB spread. Analysis of multi-cytokine profiles ex vivo after stimulation of PBMCs from LTBI and active MTB subjects indicate the real possibility of successfully discerning these two disease states within 24 hours of a subject's blood draw. Due to the unparalleled sensitivity, low cost, and ease of use of Elispot assays, we propose that via a multiplex Elispot platform the accurate distinction of LTBI from active MTB-infected individuals is within reach
Serum and Urine Concentrations of Flunitrazepam and Metabolites, after a Single Oral Dose, by Immunoassay and GC-MS
A clinical study was conducted to assess the ability of commercially available immunoassays to detect flunitrazepam (FNP) in plasma and urine samples and to compare the results with those obtained by gas chromatography-mass spectrometry (GC-MS). The clinical study consisted of four individuals (two male and two female) who had taken a single 2-mg dose of FNP. Serum was collected over a 48-h period and urine was collected over a 72-h period. The serum and urine samples were analyzed by the COBAS® INTEGRA Serum Benzodiazepines assay (SBENZ), the TDx serum and urine Benzodiazepines assay, and GC-MS. The GC-MS procedure was developed for analysis of FNP and metabolites in plasma and urine using an acid hydrolysis step resulting in the formation of specific benzophenones corresponding to FNP and its metabolites. The relative sensitivities of the assays for the detection of FNP and metabolites in serum and urine were GC-MS > SBFNZ > TDx. The immunoassay results for serum samples showed peak concentrations of FNP metabolites at 8 h after FNP ingestion for three individuals and at about 1 h for the fourth individual. The GC-MS, SBENZ, and TDx urine immunoassays detected drug above the stated limit of detection (LOD) in 44, 41, and 35 serial FNP urine samples, respectively. FNP metabolites were detected in urine samples with all three assays for up to 72 h after a 2-mg dose. The improved detection rate with the SBENZ assay as compared to the TDx assay is likely explained by its higher cross-reactivity with the major metabolite, 7-amino-flunitrazepam (7-amino-FNP), and its lower LO
Can One Measure the Weak Phase of a Penguin Diagram?
The b -> d penguin amplitude receives contributions from internal u, c and
t-quarks. We show that it is impossible to measure the weak phase of any of
these penguin contributions without theoretical input. However, it is possible
to obtain the weak phase if one makes a single assumption involving the
hadronic parameters. With such an assumption, one can test for the presence of
new physics in the b -> d flavour-changing neutral current by comparing the
weak phase of B_d^0-{\bar B}_d^0 mixing with that of the t-quark contribution
to the b -> d penguin.Comment: 20 pages, no figure
Inhomogeneous chiral symmetry breaking in noncommutative four fermion interactions
The generalization of the Gross-Neveu model for noncommutative 3+1 space-time
has been analyzed. We find indications that the chiral symmetry breaking occurs
for an inhomogeneous background as in the LOFF phase in condensed matter.Comment: 17 pages, 2 figures, published version, minor correction
Cyclotomic integers, fusion categories, and subfactors
Dimensions of objects in fusion categories are cyclotomic integers, hence
number theoretic results have implications in the study of fusion categories
and finite depth subfactors. We give two such applications. The first
application is determining a complete list of numbers in the interval (2,
76/33) which can occur as the Frobenius-Perron dimension of an object in a
fusion category. The smallest number on this list is realized in a new fusion
category which is constructed in the appendix written by V. Ostrik, while the
others are all realized by known examples. The second application proves that
in any family of graphs obtained by adding a 2-valent tree to a fixed graph,
either only finitely many graphs are principal graphs of subfactors or the
family consists of the A_n or D_n Dynkin diagrams. This result is effective,
and we apply it to several families arising in the classification of subfactors
of index less then 5.Comment: 47 pages, with an appendix by Victor Ostri
Appealing to motivation to change attitudes, intentions, and behavior: A systematic review and meta-analysis of 702 experimental tests of the effects of motivational message matching on persuasion.
Message matching refers to the design and distribution of persuasive messages such that message features (e.g., the themes emphasized) align with characteristics of the target audience (e.g., their personalities). Motivational message matching is a form of this technique that seeks to enhance persuasion by matching specifically to differences in motivational characteristics (e.g., salient goals, needs, values). Despite the widespread use of motivational matching, there is little understanding of how and when to use it. We conducted a preregistered (PROSPERO CRD42019116688; https://osf.io/rpjdg) systematic review and three-level meta-analysis of 702 experimental studies on motivational matching (synthesizing 5,251 effect sizes from N = 206,482). Studies were inclusive of publications until December 2018 and primarily identified using APA PsycINFO, MEDLINE, and Scopus. We evaluate moderation using metaregressions and provide bias assessments (sensitivity analyses, funnel plots). Motivational matching increases persuasion by an average of r = .20 (95% CI [.18, .22]) as assessed by differences in attitudes, intentions, self-reported behavior, and observed behavior, relative to comparison conditions. This effect is larger than previously observed for other message matching approaches (e.g., message tailoring, message framing), which usually average r < .10. Although motivational matching can effectively improve persuasion, its effects are also marked by meaningful heterogeneity. Notably, motivational matching effects are largest when matching to contextual factors (than to individual differences), when compared to messages that conflict with people’s motivations, and when target characteristics are manipulated rather than assessed. Through this review, we develop and evaluate theoretical propositions that inform the optimization of motivational matching
Ohta-Jasnow-Kawasaki Approximation for Nonconserved Coarsening under Shear
We analytically study coarsening dynamics in a system with nonconserved
scalar order parameter, when a uniform time-independent shear flow is present.
We use an anisotropic version of the Ohta-Jasnow-Kawasaki approximation to
calculate the growth exponents in two and three dimensions: for d=3 the
exponents we find are the same as expected on the basis of simple scaling
arguments, that is 3/2 in the flow direction and 1/2 in all the other
directions, while for d=2 we find an unusual behavior, in that the domains
experience an unlimited narrowing for very large times and a nontrivial
dynamical scaling appears. In addition, we consider the case where an
oscillatory shear is applied to a two-dimensional system, finding in this case
a standard t^1/2 growth, modulated by periodic oscillations. We support our
two-dimensional results by means of numerical simulations and we propose to
test our predictions by experiments on twisted nematic liquid crystals.Comment: 25 RevTeX pages, 7 EPS figures. To be published in Phys. Rev.
Rescattering and chiral dynamics in B\to \rho\pi decay
We examine the role of B^0(\bar B^0) \to \sigma \pi^0 \to \pi^+\pi^- \pi^0
decay in the Dalitz plot analysis of B^0 (\bar B^0) \to \rho\pi \to
\pi^+\pi^-\pi^0 decays, employed to extract the CKM parameter \alpha. The
\sigma \pi channel is significant because it can break the relationship between
the penguin contributions in B\to\rho^0\pi^0, B\to\rho^+\pi^-, and
B\to\rho^-\pi^+ decays consequent to an assumption of isospin symmetry. Its
presence thus mimics the effect of isospin violation. The \sigma\pi^0 state is
of definite CP, however; we demonstrate that the B\to\rho\pi analysis can be
generalized to include this channel without difficulty. The \sigma or
f_0(400-1200) ``meson'' is a broad I=J=0 enhancement driven by strong \pi\pi
rescattering; a suitable scalar form factor is constrained by the chiral
dynamics of low-energy hadron-hadron interactions - it is rather different from
the relativistic Breit-Wigner form adopted in earlier B\to\sigma\pi and
D\to\sigma\pi analyses. We show that the use of this scalar form factor leads
to an improved theoretical understanding of the measured ratio Br(\bar B^0 \to
\rho^\mp \pi^\pm) / Br(B^-\to \rho^0 \pi^-).Comment: 26 pages, 8 figs, published version. typos fixed, minor change
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