129 research outputs found
Pathological study of elective nephrectomies for a two year period
Background: Nephrectomies whether partial, total or radical are common surgical procedures these days with trauma being the most common cause of an emergency nephrectomy. The indications of elective nephrectomies vary with different age groups- malignancies being common in the elderly age group and non-neoplastic indications of nephrectomy may present in any age group. The present study was undertaken in view of the increasing elective nephrectomies in our area thus analyzing the common causes requiring nephrectomy as a treatment. The present study also aimed at determining the age and sex distribution of various renal lesions requiring a nephrectomy.Methods: It was a prospective study for a period of 2 years - January 2013 to December 2014. A total of 45 nephrectomies were included in the study. Detailed clinical, biochemical and imaging findings were taken into consideration before analyzing each case. Results: There was a male predominance(64.4%) and 26.6% of the cases were in the age group of 40-50 years. 95.5% of the nephrectomies were performed for a non-neoplastic indication. Involvement of the right and left kidney was almost equal in the study. Chronic pyelonephritis was the most common histopathological diagnosis(68.8%).Conclusion: Inflammatory causes more commonly required a nephrectomy in the study population. Chronic calculous pyelonephritis was the most common underlying pathophysiology leading to a nonfunctioning kidney thus highlighting the early treatment of renal calculi.
Tests of light-lepton universality in angular asymmetries of decays
We present the first comprehensive tests of light-lepton universality in the
angular distributions of semileptonic \Bz-meson decays to charged spin-1
charmed mesons. We measure five angular-asymmetry observables as functions of
the decay recoil that are sensitive to lepton-universality-violating
contributions. We use events where one neutral \B is fully reconstructed in
\PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion
integrated luminosity from electron-positron collisions collected with the
\belletwo detector. We find no significant deviation from the standard model
expectations
Measurement of asymmetries and branching-fraction ratios for and with using Belle and Belle II data
We measure asymmetries and branching-fraction ratios for and decays with , where
is a superposition of and . We use the full data set of the
Belle experiment, containing pairs, and data from the
Belle~II experiment, containing pairs, both collected
in electron-positron collisions at the resonance. Our results
provide model-independent information on the unitarity triangle angle .Comment: 26 pages, 8 figure
Search for an invisible in a final state with two muons and missing energy at Belle II
The extension of the standard model predicts the existence
of a lepton-flavor-universality-violating boson that couples only
to the heavier lepton families. We search for such a through its
invisible decay in the process . We use a
sample of electron-positron collisions at a center-of-mass energy of 10.58GeV
collected by the Belle II experiment in 2019-2020, corresponding to an
integrated luminosity of 79.7fb. We find no excess over the expected
standard-model background. We set 90-confidence-level upper limits on the
cross section for this process as well as on the coupling of the model, which
ranges from at low masses to 1 at
masses of 8
Search for a resonance in events with the Belle II experiment
We report the first search for a non-standard-model resonance decaying into
pairs in events in
the 3.6-10 GeV/ mass range. We use a 62.8 fb sample of
collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II
experiment at the SuperKEKB collider. The analysis probes three different
models predicting a spin-1 particle coupling only to the heavier lepton
families, a Higgs-like spin-0 particle that couples preferentially to charged
leptons (leptophilic scalar), and an axion-like particle, respectively. We
observe no evidence for a signal and set exclusion limits at 90% confidence
level on the product of cross section and branching fraction into pairs,
ranging from 0.7 fb to 24 fb, and on the couplings of these processes. We
obtain world-leading constraints on the couplings for the leptophilic scalar
model for masses above 6.5 GeV/ and for the axion-like particle model over
the entire mass range
Measurement of the branching fraction and asymmetry of decays using pairs in Belle II data
We report measurements of the branching fraction and asymmetry in
decays reconstructed at Belle II in an
electron-positron collision sample containing
pairs. We measure a branching fraction \mathcal{B}(\Bpipi) =
(1.38 \pm 0.27 \pm 0.22) \times 10^{-6} and a asymmetry \Acp(\Bpipi)
= 0.14 \pm 0.46 \pm 0.07, where the first uncertainty is statistical and the
second is systematic
Measurement of asymmetries in decays with Belle II
We present a measurement of time-dependent rate asymmetries in decays to search for non-standard-model physics in transitions. The data sample is collected with the Belle II
detector at the SuperKEKB asymmetric-energy collider in 2019-2022
and contains bottom-antibottom mesons from
resonance decays. We reconstruct signal events and
extract the charge-parity () violating parameters from a fit to the
distribution of the proper-decay-time difference of the two mesons. The
measured direct and mixing-induced asymmetries are
and , respectively, where the first
uncertainties are statistical and the second are systematic. The results are
compatible with the asymmetries observed in
transitions
First measurement of as an inclusive test of the anomaly
We measure the tau-to-light-lepton ratio of inclusive -meson branching
fractions , where indicates an electron or muon, and thereby test
the universality of charged-current weak interactions. We select events that
have one fully reconstructed meson and a charged lepton candidate from
of electron-positron collision data collected with the
Belle II detector. We find , in agreement with standard-model expectations. This
is the first direct measurement of
Measurement of branching fractions and direct asymmetries for and decays at Belle II
We report measurements of the branching fractions and direct
asymmetries of the decays , , , and , and use these for testing the standard
model through an isospin-based sum rule. In addition, we measure the branching
fraction and direct asymmetry of the decay and
the branching fraction of the decay . The data are
collected with the Belle II detector from collisions at the
resonance produced by the SuperKEKB asymmetric-energy collider
and contain bottom-antibottom meson pairs. Signal yields are
determined in two-dimensional fits to background-discriminating variables, and
range from 500 to 3900 decays, depending on the channel. We obtain for the sum rule, in agreement with the standard model
expectation of zero and with a precision comparable to the best existing
determinations
Precise measurement of the lifetime at Belle II
We measure the lifetime of the meson using a data sample of 207
fb collected by the Belle II experiment running at the SuperKEKB
asymmetric-energy collider. The lifetime is determined by fitting the
decay-time distribution of a sample of
decays. Our result is \tau^{}_{D^+_s} = (498.7\pm
1.7\,^{+1.1}_{-0.8}) fs, where the first uncertainty is statistical and the
second is systematic. This result is significantly more precise than previous
measurements.Comment: 7 pages, 4 figures, to be submitted to Physical Review Letter
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