9,344 research outputs found
Quasi-two-body decays in the perturbative QCD approach
In this paper, we calculated the branching ratios of the quasi-two-body
decays
by employing the perturbative QCD (PQCD) approach. The contributions from the
-wave resonances , and were taken into
account. The two-pion distribution amplitude is
parameterized by the vector current time-like form factor to study
the considered decay modes. We found that (a) the PQCD predictions for the
branching ratios of the considered quasi-two-body decays are in the order of
, while the two-body decay rates are extracted from those for the
corresponding quasi-two-body decays; (b) the whole pattern of the pion form
factor-squared measured by the BABAR Collaboration could be
understood based on our theoretical results; (c) the general expectation based
on the similarity between and
decays are confirmed: is consistent with the measured
within errors; and (d) new ratios
and among the branching ratios of the
considered decay modes are defined and could be tested by future experiments.Comment: 10 pages, 3 figure
Quasi-two-body decays in the perturbative QCD approach
We study the quasi-two-body decays by employing
the perturbative QCD approach. The two-meson distribution amplitudes
\Phi_{K\pi}^{\text{P-wave}} are adopted to describe the final state
interactions of the kaon-pion pair in the resonance region. The resonance line
shape for the -wave component in the time-like form factor
is parameterized by the relativistic Breit-Wigner function. For
most considered decay modes, the theoretical predictions for their branching
ratios are consistent with currently available experimental measurements within
errors. We also disscuss some ratios of the branching fractions of the
concerned decay processes. More precise data from LHCb and Belle-II are
expected to test our predictions.Comment: 10 pages, 3 figures and 2 tables.To be published in EPJ
Analysis of influence factors of free cataract surgery in suburban district of one city in middle China
AIM:To investigate the reasons of the barriers to free cataract surgery in suburban area of one city in middle China. <p>METHODS: From 2008 to 2009, in Sight Rehabilitation Programme of Cataract in suburban district of one city in middle China, all visually significant cataract patients screened were questioned about why he/she did not accept free cataract surgery. The answers were recorded and analyzed. <p>RESULTS: Of 892 screened patients, only 387 patients(43.39%)wanted a free cataract surgery at first. At last 490 patients(54.93%)accepted free surgery. The main reasons for patients who did not accept free surgery include: be afraid of surgery and wanting other treatments(193, 21.64%), thinking the eyesight was enough for daily life(148, 16.59%), worrying about that the result would not be good as those paid for surgery(147, 16.48%), and other reasons(17, 1.91%).<p>CONCLUSION: The reasons of the barriers to free cataract surgery include patients' ignorance, surgery outcome of patients around, and working mode of designated surgical hospital
LeCaRDv2: A Large-Scale Chinese Legal Case Retrieval Dataset
As an important component of intelligent legal systems, legal case retrieval
plays a critical role in ensuring judicial justice and fairness. However, the
development of legal case retrieval technologies in the Chinese legal system is
restricted by three problems in existing datasets: limited data size, narrow
definitions of legal relevance, and naive candidate pooling strategies used in
data sampling. To alleviate these issues, we introduce LeCaRDv2, a large-scale
Legal Case Retrieval Dataset (version 2). It consists of 800 queries and 55,192
candidates extracted from 4.3 million criminal case documents. To the best of
our knowledge, LeCaRDv2 is one of the largest Chinese legal case retrieval
datasets, providing extensive coverage of criminal charges. Additionally, we
enrich the existing relevance criteria by considering three key aspects:
characterization, penalty, procedure. This comprehensive criteria enriches the
dataset and may provides a more holistic perspective. Furthermore, we propose a
two-level candidate set pooling strategy that effectively identify potential
candidates for each query case. It's important to note that all cases in the
dataset have been annotated by multiple legal experts specializing in criminal
law. Their expertise ensures the accuracy and reliability of the annotations.
We evaluate several state-of-the-art retrieval models at LeCaRDv2,
demonstrating that there is still significant room for improvement in legal
case retrieval. The details of LeCaRDv2 can be found at the anonymous website
https://github.com/anonymous1113243/LeCaRDv2
An Intent Taxonomy of Legal Case Retrieval
Legal case retrieval is a special Information Retrieval~(IR) task focusing on
legal case documents. Depending on the downstream tasks of the retrieved case
documents, users' information needs in legal case retrieval could be
significantly different from those in Web search and traditional ad-hoc
retrieval tasks. While there are several studies that retrieve legal cases
based on text similarity, the underlying search intents of legal retrieval
users, as shown in this paper, are more complicated than that yet mostly
unexplored. To this end, we present a novel hierarchical intent taxonomy of
legal case retrieval. It consists of five intent types categorized by three
criteria, i.e., search for Particular Case(s), Characterization, Penalty,
Procedure, and Interest. The taxonomy was constructed transparently and
evaluated extensively through interviews, editorial user studies, and query log
analysis. Through a laboratory user study, we reveal significant differences in
user behavior and satisfaction under different search intents in legal case
retrieval. Furthermore, we apply the proposed taxonomy to various downstream
legal retrieval tasks, e.g., result ranking and satisfaction prediction, and
demonstrate its effectiveness. Our work provides important insights into the
understanding of user intents in legal case retrieval and potentially leads to
better retrieval techniques in the legal domain, such as intent-aware ranking
strategies and evaluation methodologies.Comment: 28 pages, work in proces
Small deviations of iterated processes in space of trajectories
We derive logarithmic asymptotics of probabilities of small deviations for
iterated processes in the space of trajectories. We find conditions under which
these asymptotics coincide with those of processes generating iterated
processes. When these conditions fail the asymptotics are quite different
Determination of tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry
A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS)
method for determination of tetramethylpyrazine in rat plasma was developed. After addition of
phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation.
Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with
(40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI)
source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to
quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8
for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma.
Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine
from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were
less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic
research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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