1,168 research outputs found
Reconsideration of the QCD corrections to the decays into light hadrons using the principle of maximum conformality
In the paper, we analyze the decays into light hadrons at the
next-to-leading order QCD corrections by applying the principle of maximum
conformality (PMC). The relativistic correction at the -order level has been included in the discussion, which gives about
contribution to the ratio . The PMC, which satisfies the renormalization
group invariance, is designed to obtain a scale-fixed and scheme-independent
prediction at any fixed order. To avoid the confusion of treating -terms,
we transform the usual pQCD series into the one under the
minimal momentum space subtraction scheme. To compare with the prediction under
conventional scale setting, , after applying the PMC, we obtain
, where the
errors are squared averages of the ones caused by and . The PMC prediction agrees with the recent PDG value within errors, i.e.
. Thus we think the mismatching
of the prediction under conventional scale-setting with the data is due to
improper choice of scale, which however can be solved by using the PMC.Comment: 5 pages, 2 figure
Butane-1,2,3,4-tetracarboxylic acid–4,4′-bipyridine (1/2)
The hydrothermal reaction of butane-1,2,3,4-tetracarboxylic acid (H4butca), 4,4′-bipyridine (bipy) and Mn(SO4)2·H2O afforded a new co-crystal, C8H10O8·2C10H8N2 or H4butca·2(bipy), in which strong O—H⋯N hydrogen-bonding and weak π–π stacking [centroid–centroid distance = 3.8459 (19) Å] interactions assemble the organic molecules into a three-dimensional supramolecular framework. C—H⋯O interactions are also present. The whole molecule has inversion symmetry
Structure-driven intercalated architecture of septuple-atomic-layer family with diverse properties from semiconductor to topological insulator to Ising superconductor
Motivated by the fact that septuple-atomic-layer MnBiTe can be
structurally viewed as the combination of double-atomic-layer MnTe
intercalating into quintuple-atomic-layer BiTe, we present a general
approach of constructing twelve septuple-atomic-layer - and
- monolayer family (\emph{i} = 1 to 6) by intercalating
MoS-type monolayer into InSe-type AZ monolayer. Besides
reproducing the experimentally synthesized -MoSiN,
-WSiN and -MnBiTe monolayer materials,
another 66 thermodynamically and dynamically stable were predicted,
which span a wide range of properties upon the number of valence electrons
(VEC). with the rules of 32 or 34 VEC are mostly semiconductors with
direct or indirect band gap and, however, with 33 VEC are generally metal,
half-metal ferromagnetism, or spin-gapless semiconductor upon whether or not an
unpaired electron is spin polarized. Moreover, we propose
-WSiP for the spin-valley polarization,
-TaSiN for Ising superconductor and -SrGaSe
for topological insulator.Comment: Maintext 9 pages; 5 figures; Supplementary Materials 8 figures and 4
table
Surgical techniques for early-stage thymoma: Video-assisted thoracoscopic thymectomy versus transsternal thymectomy
ObjectiveThe present study compared the outcomes between patients who had undergone video-assisted thoracoscopic surgery (VATS) thymectomy and transsternal (TS) thymectomy for Masaoka stage I and II thymoma.MethodsThe outcomes of 262 patients without myasthenia gravis who had undergone surgery for Masaoka stage I and II thymoma from January 2008 to December 2012 at our center were retrospectively evaluated. The study included 125 patients who had undergone unilateral VATS thymectomy (VATS group) and 137 patients who had undergone TS thymectomy (TS group).ResultsThe VATS group had a shorter operative time than the TS group (170 vs 210 minutes, P < .001). The VATS group also had a smaller intraoperative blood loss (200 vs 450 mL, P < .001), smaller pleural drainage volume in the first 24 hours postoperatively (300 vs 500 mL, P < .0010), shorter postoperative pleural drainage duration (3 vs 5 days, P < .001), and shorter postoperative hospital stay (8 vs 10 days, P < .001). Four patients in the VATS group underwent conversion to open surgery because of injury to the innominate vein. The postoperative complication rate was similar between the 2 groups. One patient in the VATS group developed pleural recurrence, and one in the TS group developed local recurrence.ConclusionsUnilateral VATS thymectomy for Masaoka stage I and II thymoma is technically feasible and safe and is less invasive than TS thymectomy, with a shorter duration of surgery, less intraoperative blood loss, less postoperative pleural drainage, shorter postoperative pleural drainage duration, and shorter postoperative hospital stay. We have concluded that it is preferable to perform VATS thymectomy, although perhaps under certain circumstances sternotomy might be preferred. The oncologic outcomes were comparable between the 2 procedures. Additional follow-up is required to evaluate the long-term outcomes
Attention Mechanisms in Computer Vision: A Survey
Humans can naturally and effectively find salient regions in complex scenes.
Motivated by this observation, attention mechanisms were introduced into
computer vision with the aim of imitating this aspect of the human visual
system. Such an attention mechanism can be regarded as a dynamic weight
adjustment process based on features of the input image. Attention mechanisms
have achieved great success in many visual tasks, including image
classification, object detection, semantic segmentation, video understanding,
image generation, 3D vision, multi-modal tasks and self-supervised learning. In
this survey, we provide a comprehensive review of various attention mechanisms
in computer vision and categorize them according to approach, such as channel
attention, spatial attention, temporal attention and branch attention; a
related repository https://github.com/MenghaoGuo/Awesome-Vision-Attentions is
dedicated to collecting related work. We also suggest future directions for
attention mechanism research.Comment: 27 pages, 9 figure
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