257 research outputs found
Semileptonic meson decays to S-wave charmonia and within the covariant light-front approach
In this work, we investigate the semileptonic decays of meson to
, and within the framework of
covariant light-front quark model (CLFQM). We combine the helicity amplitudes
via the corresponding form factors to obtain the branching ratios of the
semileptonic decays , and with
. In view of the anomaly released by the LHCb
collaboration, it is necessary to calculate the ratios with
systematically, which are helpful
to check the lepton flavor universality (LFU). Furthermore, we also take into
account another two physical observables, one is the longitudinal polarization
fraction and the other is the forward-backward asymmetry ,
which can provide new clues to understand the anomaly. Such
theoretical predictions are necessary and interesting, which can be tested in
the future LHCb experiments.Comment: 23 pages, 4 figure
Quasi-two-body decays in the perturbative QCD
In this work, we investigate the quasi-two-body decays with using the perturbative QCD(PQCD)
approach. The description of final state interactions between the pair
is achieved through the two-meson distribution amplitudes(DAs), which are
normalized to the time-like form factor. The PQCD predictions on the branching
ratios of the quasi-two-body decays show an obvious
hierarchy: and .
From the invariant mass -dependence of the decay spectrum for each
channel, one can find that the branching fraction is concentrated in a narrow
region around the pole mass. So one can obtain the branching ratios for
the corresponding two-body decays under the narrow width
approximation. We find that the branching ratios of the decays
are consistent well with the previous PQCD calculations within errors. These
predictions will be tested by the future experiments.Comment: 12 pages, 3 figures, accepted for publication in Chin. Phys.
Quasi-two-body decays in the perturbative QCD
In this work we study the quasi-two-body decays in the perturbative QCD (PQCD) approach.
The two-meson distribution amplitudes (DAs) are
introduced to describe the final state interactions of the K \pi pair, which
involve the time-like form factors F_{K\pi}(s) parameterized by the
relativistic Breit-Wigner function and the Gegenbauer polynomials. We calculate
the branching ratios for these quasi-two-body decays, from which one can obtain
the branching raios for the corresponding two-body decays under the narrow
width approximation relation. We find that and have the largest branching ratios, which can reach up to ,
while the branching ratios for other two-body decays are very small and only
about . As we expected that the branching ratios of the
pure annihilation decays are usually small, while in our considered such type
of decays, the channel has the largest branching
ratio, which is near . These results are consistent with the
previously PQCD calculations obtained in the two-body framework, which can be
tested by the future LHCb experiments. For the decays and , we calculate their direct CP
violations and find that is the largest one, which is
possible measured by the present LHCb experiments. For the pure annihilation
type decays, there is no CP violations because only the tree operators are
involved. Furthermore, we also give the differential distributions of the
branching ratios and the direct CP violations for the decays .Comment: 15 pages, 3 figures, 2 table
A HRNet-based Rehabilitation Monitoring System
The rehabilitation treatment helps to heal minor sports and occupational
injuries. In a traditional rehabilitation process, a therapist will assign
certain actions to a patient to perform in between hospital visits, and it will
rely on the patient to remember actions correctly and the schedule to perform
them. Unfortunately, many patients forget to perform actions or fail to recall
actions in detail. As a consequence, the rehabilitation treatment is hampered
or, in the worst case, the patient may suffer from additional injury caused by
performing incorrect actions. To resolve these issues, we propose a HRNet-based
rehabilitation monitoring system, which can remind a patient when to perform
the actions and display the actions for the patient to follow via the patient's
smartphone. In addition, it helps the therapist to monitor the progress of the
rehabilitation for the patient. Our system consists of an iOS app and several
components at the server side. The app is in charge of displaying and
collecting action videos. The server computes the similarity score between the
therapist's actions and the patient's in the videos to keep track of the number
of repetitions of each action. Theses stats will be shown to both of the
patient and therapist. The extensive experiments show that the F1-Score of the
similarity calculation is as high as 0.9 and the soft accuracy of the number of
repetitions is higher than 90%
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Dietary Intake of Fatty Acids, Total Cholesterol, and Stomach Cancer in a Chinese Population.
To investigate the associations between dietary fatty acids and cholesterol consumption and stomach cancer (SC), we analyzed data from a population-based case-control study with a total of 1900 SC cases and 6532 controls. Dietary data and other risk or protective factors were collected by face-to-face interviews in Jiangsu Province, China, from 2003 to 2010. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multiple unconditional logistic regression models and an energy-adjusted method. The joint associations between dietary factors and known risk factors on SC were examined. We observed positive associations between dietary saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and total cholesterol and the development of SC, comparing the highest versus lowest quarters. Increased intakes of dietary SFAs (p-trend = 0.005; aOR, 1.11; 95% CI, 1.01-1.22 with a 7 g/day increase as a continuous variable) and total cholesterol (p-trend < 0.001; aOR, 1.13; 95% CI, 1.06-1.22 with a 250 mg/day increase as a continuous variable) were monotonically associated with elevated odds of developing SC. Our results indicate that dietary SFAs, MUFAs, and total cholesterol are associated with stomach cancer, which might provide a potential dietary intervention for stomach cancer prevention
Raw Garlic Consumption and Risk of Liver Cancer: A Population-Based Case-Control Study in Eastern China.
Although the major risk factors for liver cancer have been established, preventive factors for liver cancer have not been fully explored. We evaluated the association between raw garlic consumption and liver cancer in a large population-based case-control study in Eastern China. The study was conducted in Jiangsu, China, from 2003 to 2010. A total of 2011 incident liver cancer cases and 7933 randomly selected population-controls were interviewed. Epidemiological data including raw garlic intake and other exposures were collected, and serum markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection were assayed. Overall, eating raw garlic twice or more per week was inversely associated with liver cancer, with an adjusted odds ratio (aOR) of 0.77 (95% confidence interval (CI): 0.62-0.96) compared to those ingesting no raw garlic or less than twice per week. In stratified analyses, high intake of raw garlic was inversely associated with liver cancer among Hepatitis B surface antigen (HBsAg) negative individuals, frequent alcohol drinkers, those having history of eating mold-contaminated food or drinking raw water, and those without family history of liver cancer. Marginal interactions on an additive scale were observed between low raw garlic intake and HBsAg positivity (attributable proportion due to interaction (AP) = 0.31, 95% CI: -0.01-0.62) and heavy alcohol drinking (AP = 0.28, 95% CI: 0.00-0.57). Raw garlic consumption is inversely associated with liver cancer. Such an association shed some light on the potential etiologic role of garlic intake on liver cancer, which in turn might provide a possible dietary intervention to reduce liver cancer in Chinese population
Validation of reference genes for gene expression studies in post-harvest leaves of tea plant (Camellia sinensis)
Tea is one of three major non-alcoholic beverages that are popular all around the world. The economic value of tea product largely depends on the post-harvest physiology of tea leaves. The utilization of quantitative reverse transcription polymerase chain reaction is a widely accepted and precise approach to determine the target gene expression of tea plants, and the reliability of results hinges on the selection of suitable reference genes. A few reliable reference genes have been documented using various treatments and different tissues of tea plants, but none has been done on post-harvest leaves during the tea manufacturing process. The present study selected and analyzed 15 candidate reference genes: Cs18SrRNA, CsGADPH, CsACT, CsEF-1α, CsUbi, CsTUA, Cs26SrRNA, CsRuBP, CsCYP, CselF-4α, CsMON1, CsPCS1, CsSAND, CsPPA2, CsTBP. This study made an assessment on the expression stability under two kinds of post-harvest treatment, turn over and withering, using three algorithms—GeNorm, Normfinder, and Bestkeeper. The results indicated that the three commonly used reference genes, CsTUA, Cs18SrRNA, CsRuBP, together with Cs26SrRNA, were the most unstable genes in both the turn over and withering treatments. CsACT, CsEF-1α, CsPPA2, and CsTBP were the top four reference genes in the turn over treatment, while CsTBP, CsPCS1, CsPPA2, CselF-4α, and CsACT were the five best reference genes in the withering group. The expression level of lipoxygenase genes, which were involved in a number of diverse aspects of plant physiology, including wounding, was evaluated to validate the findings. To conclude, we found a basis for the selection of reference genes for accurate transcription normalization in post-harvest leaves of tea plants
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