344 research outputs found
U-Spin Symmetry in Doubly Cabibbo-Suppressed Charmed Meson Decays
We prove a U-spin amplitude triangle relation among doubly Cabibbo-suppressed
(DCS) charmed meson decays, and , congruent to an isospin relation among corresponding Cabibbo-favored
(CF) decays. U-spin breaking in relative phases between CF and DCS amplitudes
affects time-dependent studies of D^0-\od mixing. Comparison of final state
phase patterns in DCS and CF amplitude triangles, which can shed some light on
these phases, is carried out in a phenomenological framework incorporating
resonance contributions.Comment: Two references updated, to appear in Phys. Lett.
Two-Body Cabibbo-Suppressed Charmed Meson Decays
Singly-Cabibbo-suppressed decays of charmed particles governed by the quark
subprocesses and are analyzed using a
flavor-topology approach, based on a previous analysis of the Cabibbo-favored
decays governed by . Decays to and , where is a
pseudoscalar meson and is a vector meson, are considered. We include
processes in which and are produced.Comment: 18 pages, latex, 2 figures, to be submitted to Phys. Rev.
Quantum error mitigated classical shadows
Classical shadows enable us to learn many properties of a quantum state Ï with very few measurements. However, near-term and early fault-tolerant quantum computers will only be able to prepare noisy quantum states Ï and it is thus a considerable challenge to efficiently learn properties of an ideal, noise-free state Ïid. We consider error mitigation techniques, such as probabilistic error cancelation (PEC), zero noise extrapolation (ZNE), and symmetry verification (SV), which have been developed for mitigating errors in single expected value measurements and generalize them for mitigating errors in classical shadows. We find that PEC is the most natural candidate and thus develop a thorough theoretical framework for PEC shadows with the following rigorous theoretical guarantees: PEC shadows are an unbiased estimator for the ideal quantum state Ïid; the sample complexity for simultaneously predicting many linear properties of Ïid is identical to that of the conventional shadows approach up to a multiplicative factor, which is the sample overhead due to error mitigation. Due to efficient postprocessing of shadows, this overhead does not depend directly on the number of qubits but rather grows exponentially with the number of noisy gates. The broad set of tools introduced in this work may be instrumental in exploiting near-term and early fault-tolerant quantum computers: we demonstrate in detailed numerical simulations a range of practical applications of quantum computers that will significantly benefit from our techniques
Quantum Error Mitigated Classical Shadows
Classical shadows enable us to learn many properties of a quantum state
with very few measurements. However, near-term and early fault-tolerant
quantum computers will only be able to prepare noisy quantum states and
it is thus a considerable challenge to efficiently learn properties of an
ideal, noise free state . We consider error mitigation techniques,
such as Probabilistic Error Cancellation (PEC), Zero Noise Extrapolation (ZNE)
and Symmetry Verification (SV) which have been developed for mitigating errors
in single expected value measurements and generalise them for mitigating errors
in classical shadows. We find that PEC is the most natural candidate and thus
develop a thorough theoretical framework for PEC shadows with the following
rigorous theoretical guarantees: PEC shadows are an unbiased estimator for the
ideal quantum state ; the sample complexity for simultaneously
predicting many linear properties of is identical to that of the
conventional shadows approach up to a multiplicative factor which is the sample
overhead due to error mitigation. Due to efficient post-processing of shadows,
this overhead does not depend directly on the number of qubits but rather grows
exponentially with the number of noisy gates. The broad set of tools introduced
in this work may be instrumental in exploiting near-term and early
fault-tolerant quantum computers: We demonstrate in detailed numerical
simulations a range of practical applications of quantum computers that will
significantly benefit from our techniques.Comment: The first two authors contributed equally. 21 pages, 5 figure
Proliferation and Propagation of Breakthrough Performance Management Theories and Praxes
The articles included in this special issue look broadly at the proliferation (widespread) and propagation (deliberate attempt to implant in other disciplines/contexts) of breakthrough (significant, high impact, renowned) performance management theories and praxes (cf. practices, for its acceptability and custom use)
Influence of Gelatin Source and Bloom Number on Gelatin Methacryloyl Hydrogels Mechanical and Biological Properties for Muscle Regeneration
Approximately half of an adult humanâs body weight is made up of muscles. Thus, restoring the functionality and aesthetics of lost muscle tissue is critical. The body is usually able to repair minor muscle injuries. However, when volumetric muscle loss occurs due to tumour extraction, for instance, the body will form fibrous tissue instead. Gelatin methacryloyl (GelMA) hydrogels have been applied for drug delivery, tissue adhesive, and various tissue engineering applications due to their tuneable mechanical properties. Here, we have synthesised GelMA from different gelatin sources (i.e., porcine, bovine, and fish) with varying bloom numbers, which refers to the gel strength, and investigated for the influence of the source of gelatin and the bloom number on biological activities and mechanical properties. The results indicated that the source of the gelatin and variable bloom numbers have an impact on GelMA hydrogel properties. Furthermore, our findings established that the bovine-derived gelatin methacryloyl (B-GelMA) has better mechanical properties than the other varieties composed of porcine and fish with 60 kPa, 40 kPa, and 10 kPa in bovine, porcine, and fish, respectively. Additionally, it showed a noticeably greater swelling ratio (SR) ~1100% and a reduced rate of degradation, improving the stability of hydrogels and giving cells adequate time to divide and proliferate to compensate for muscle loss. Furthermore, the bloom number of gelatin was also proven to influence the mechanical properties of GelMA. Interestingly, although GelMA made of fish had the lowest mechanical strength and gel stability, it demonstrated excellent biological properties. Overall, the results emphasise the importance of gelatin source and bloom number, allowing GelMA hydrogels to have a wide range of mechanical and excellent biological properties and making them suitable for various muscle tissue regeneration applications
Loss to follow-up after pregnancy among Sub-Saharan Africa-born women living with HIV in England, Wales and Northern Ireland:results from a large national cohort
BACKGROUND: Little is known about retention in human immunodeficiency virus (HIV) care in HIV-positive women after pregnancy in the United Kingdom. We explored the association between loss to follow-up (LTFU) in the year after pregnancy, maternal place of birth and duration of UK residence, in HIV-positive women in England, Wales, and Northern Ireland. METHODS: We analyzed combined data from 2 national data sets: the National Study of HIV in Pregnancy and Childhood; and the Survey of Prevalent HIV Infections Diagnosed, including pregnancies in 2000 to 2009 in women with diagnosed HIV. Logistic regression models were fitted with robust standard errors to estimate adjusted odds ratios (AOR). RESULTS: Overall, 902 of 7211 (12.5%) women did not access HIV care in the year after pregnancy. Factors associated with LTFU included younger age, last CD4 in pregnancy of 350 cells/ÎŒL or greater and detectable HIV viral load at the end of pregnancy (all P < 0.001). On multivariable analysis, LTFU was more likely in sub-Saharan Africa-born (SSA-born) women than white UK-born women (AOR, 2.17; 95% confidence interval, 1.50â3.14; P < 0.001). The SSA-born women who had migrated to the UK during pregnancy were 3 times more likely than white UK-born women to be lost to follow-up (AOR, 3.19; 95% confidence interval, 1.94â3.23; P < 0.001). CONCLUSIONS: One in 8 HIV-positive women in England, Wales, and Northern Ireland did not return for HIV care in the year after pregnancy, with SSA-born women, especially those who migrated to the United Kingdom during pregnancy, at increased risk. Although emigration is a possible explanatory factor, disengagement from care may also play a role
Final-State Phases in Charmed Meson Two-Body Nonleptonic Decays
Observed decay rates indicate large phase differences among the amplitudes
for the charge states in and but
relatively real amplitudes in the charge states for . This
feature is traced using an SU(3) flavor analysis to a sign flip in the
contribution of one of the amplitudes contributing to the latter processes in
comparison with its contribution to the other two sets. This amplitude may be
regarded as an effect of rescattering and is found to be of magnitude
comparable to others contributing to charmed particle two-body nonleptonic
decays.Comment: 19 pages, latex, 4 figures, to be submitted to Phys. Rev.
CP Violation from Slepton Oscillations at the LHC and NLC
In supersymmetric theories the charged sleptons of different generations may
oscillate amongst themselves while they decay. In the case of three generation
oscillations, superpartner production at the LHC and NLC may lead to an
observable -violating signal . This signal is
proportional to a -violating invariant of the slepton mass matrix,
, which is not constrained by searches for the electric dipole
moment of the electron. The sensitivity of the LHC and NLC to this signal is
highly dependent on superpartner masses, but may be probed to a
level of . Observation of the -violating signal would imply a
definite structure for the slepton mass matrices and have strong implications
for models of flavor and SUSY breaking.Comment: 37 pages, REVTeX, 7 figure
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