308 research outputs found
A Theoretical Diagnosis on Light Speed Anisotropy from GRAAL Experiment
The light speed anisotropy, i.e., the variation of the light speed with
respect to the direction in an "absolute" reference frame, is a profound issue
in physics. The one-way experiment, performed at the GRAAL facility of the
European Synchrotron Radiation Facility (ESRF) in Grenoble, reported results on
the light speed anisotropy by Compton scattering of laser photons on
high-energy electrons. So far, most articles concerned with the GRAAL data have
established only the upper bounds on the anisotropy parameters based on
available theories. We use a new theory of the Lorentz invariance violation to
analyse the available GRAAL data and obtain the stringent upper limit of the
order on the Lorentz violation parameters. In the meantime,
we also can reproduce the allowed light speed anisotropy appearing in the
azimuthal distribution of the GRAAL experimental data, and find that the
best-fit parameters are compatible with the competitive upper bounds.Comment: 13 pages, 2 figures, final version in journal publicatio
Neutrino speed anomaly as signal of Lorentz violation
We make a reanalysis on the issue of neutrino speed anomaly by taking into
account the newly reported data from the ICARUS experiment and other CNGS
collaborations. We examine the consequence of the Lorentz violation on the
neutrino speed in a new framework of standard model supplement (SMS), and find
that the Lorentz violating parameters are constrained at least one order
stronger than that of the earlier OPERA report. The combination with other
phenomenological considerations puts more stringent constraints on the Lorentz
violation of neutrinos.Comment: 14 pages. Significantly improved version with updated analysis on the
relevant experiments related to neutrino speed. Matches to the final
published versio
Lorentz Violation of the Photon Sector in Field Theory Models
We compare the Lorentz violation terms of the pure photon sector between two
field theory models, namely the minimal standard model extension (SME) and the
standard model supplement (SMS). From the requirement of the identity of the
intersection for the two models, we find that the free photon sector of the SMS
can be a subset of the photon sector of the minimal SME. We not only obtain
some relations between the SME parameters, but also get some constraints on the
SMS parameters from the SME parameters. The CPT-odd coefficients
of the SME are predicted to be zero. There are 15 degrees
of freedom in the Lorentz violation matrix of free
photons of the SMS related with the same number of degrees of freedom in the
tensor coefficients , which are independent from
each other in the minimal SME, but are inter-related in the intersection of the
SMS and the minimal SME. With the related degrees of freedom, we obtain the
conservative constraints () on the elements of the photon Lorentz
violation matrix. The detailed structure of the photon Lorentz violation matrix
suggests some applications to the Lorentz violation experiments for photons.Comment: 9 pages, no figure, three tables. Final version for journal
publicatio
AMG: Automated Efficient Approximate Multiplier Generator for FPGAs via Bayesian Optimization
Approximate computing is a promising approach to reduce the power, delay, and
area in hardware design for many error-resilient applications such as machine
learning (ML) and digital signal processing (DSP) systems, in which multipliers
usually are key arithmetic units. Due to the underlying architectural
differences between ASICs and FPGAs, existing ASIC-based approximate
multipliers do not offer symmetrical gains when they are implemented by FPGA
resources. In this paper, we propose AMG, an open-source automated approximate
multiplier generator for FPGAs driven by Bayesian optimization (BO) with
parallel evaluation. The proposed method simplifies the exact half adders (HAs)
for the initial partial product (PP) compression in a multiplier while
preserving coarse-grained additions for the following accumulation. The
generated multipliers can be effectively mapped to lookup tables (LUTs) and
carry chains provided by modern FPGAs, reducing hardware costs with acceptable
errors. Compared with 1167 multipliers from previous works, our generated
multipliers can form a Pareto front with 28.70%-38.47% improvements in terms of
the product of hardware cost and error on average. All source codes, reproduced
multipliers, and our generated multipliers are available at
https://github.com/phyzhenli/AMG.Comment: 7 pages, 2023 IEEE International Conference on Field-Programmable
Technology (ICFPT
Fast Adjustable NPN Classification Using Generalized Symmetries
NPN classification of Boolean functions is a powerful technique used in many logic synthesis and technology mapping tools in FPGA design flows. Computing the canonical form of a function is the most common approach of Boolean function classification. In this paper, a novel algorithm for computing NPN canonical form is proposed. By exploiting symmetries under different phase assignments and higher-order symmetries of Boolean functions, the search space of NPN canonical form computation is pruned and the runtime is dramatically reduced. The algorithm can be adjusted to be a slow exact algorithm or a fast heuristic algorithm with lower quality. For exact classification, the proposed algorithm achieves a 30× speedup compared to a state-of-the-art algorithm. For heuristic classification, the proposed algorithm has similar performance as the state-of-the-art algorithm with a possibility to trade runtime for quality
Case report: Thoughts on two cases of total anomalous pulmonary venous connection complicated with pulmonary artery hypertension
The two primary pathological alterations of total anomalous pulmonary venous connection (TAPVC), a rare cyanotic congenital heart disease (CHD), are right heart failure and pulmonary artery hypertension (PAH). The timing and prognosis of surgery depend on the level of pulmonary hypertension. Surgery will not be an option after Eisenmenger syndrome appears. In light of this, it is crucial to assess patients’ PAH. In order to aid in the following treatment of related types of diseases, this article studied and compared the echocardiographic features and disease development of one adult and one child TAPVC patients complicated with PAH
Clinical and pathological observation of conversion therapy for malignant peritoneal mesothelioma: a case report and literature review
Background: Malignant mesothelioma (MM) is a tumor originating from the pleura, peritoneum, or pericardial cavity. It is divided into diffuse and localized malignant mesothelioma, with four subtypes in diffuse MM: epithelioid, sarcomatoid, desmoplastic, and biphasic, with biphasic being less common. The onset of this tumor is insidious, and the prognosis is extremely poor in some cases, with a median survival of 6–18 months and no standard treatment options in the past.Aims: We report a case of peritoneal malignant mesothelioma that was successfully treated with transformative therapy. We also review the literature in the hope of providing reference for the treatment and pathological diagnosis of such patients.Methods: The case of the peritoneal malignant mesothelioma was processed and reported in the routine manner for biopsy specimens at different stages.Results and conclusion: We report a case of a malignant tumor originating in the hepatorenal recess, which was diagnosed as biphasic malignant mesothelioma through a biopsy. Immunohistochemical testing showed PD-L1 expression. After multidisciplinary discussion, the patient received transformative treatment, including a trial of combined immunotherapy. The tumor significantly shrank, and the patient obtained a chance for curative surgical resection. Microscopic examination showed significant collagenization in the lesion area, with almost no residual tumor. After 19 months of comprehensive treatment, the patient developed multiple fluffy opacities under the pleura of both lungs. Transthoracic core needle biopsy under CT guidance, the pathology showed organizing pneumonia, considering it as delayed interstitial pneumonitis due to immunotherapy based on previous treatment history. Successful comprehensive treatment was achieved for this case of peritoneal malignant mesothelioma, and the patient has been alive without evidence of disease for 33 months, with long-term follow-up. In this process, the pathologist had three opportunities for pathological diagnosis, which required understanding the patient’s medical history, being attentive to the clinical purpose of the specimen, and providing accurate responses to morphological changes at different stages, along with corresponding descriptions and diagnoses to provide effective information for clinical treatment
The clinical implications of fasting serum insulin levels in patients with insulin-treated type 2 diabetes: a cross-sectional survey
ObjectiveThis study aimed to investigate the clinical implications of fasting serum insulin (FINS) levels in subjects with type 2 diabetes who were receiving insulin therapy.MethodsA total of 1,553 subjects with type 2 diabetes [774 subjects who had never received insulin treatment (N-INS) and 779 subjects who were receiving insulin therapy (constant insulin treatment, C-INS)] admitted to the Department of Endocrinology and Metabolism of Peking University People’s Hospital were enrolled in this study. Their FINS levels were measured and those with hyperinsulinemia were identified. The underlying mechanisms of hyperinsulinemia were revealed by measuring insulin antibodies (IAs) and analyzing changes in FINS levels before and after polyethylene glycol (PEG) precipitation. In addition, the clinical characteristics of patients with different types of hyperinsulinemia were compared.ResultsHigher FINS levels and a higher incidence (43.8%, 341/779) of hyperinsulinemia (FINS > 15μIU/mL) were observed in subjects with C-INS than in subjects with N-INS. Among subjects with C-INS and hyperinsulinemia, 66.9% (228/341) were IAs positive, and the incidence of IAs was found to be positively associated with FINS level. By performing PEG precipitation, we found that all subjects without IAs (i.e., those with real hyperinsulinemia) and 31.1% of subjects (71/228) with IAs (i.e., those with both real and IAs-related hyperinsulinemia) still had hyperinsulinemia after PEG precipitation, whereas FINS levels in the other 68.9% of subjects (157/228) with IAs were normal (IAs-related hyperinsulinemia) after PEG precipitation. Comparisons between the groups showed that subjects with real hyperinsulinemia showed more obvious insulin resistance characteristics, including higher lipid levels, BMIs, and homoeostasis model assessment2-estimated insulin resistance (HOMA2-IR) index, and were more likely to have hypertension, obesity, and metabolic syndromes (p < 0.05). However, the risk of hypoglycemia and glucose variability increased significantly in subjects with IAs compared with those without IAs. A cutoff of FINS to serum C-peptide ratio (≥ 9.3μIU/ng) could be used to screen IAs in clinical practice with 83.3% sensitivity and 70% specificity.ConclusionsIt is necessary to measure FINS in subjects with C-INS to distinguish between types of hyperinsulinemia, which should help to tailor treatment regimens
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