Comparing Machine Learning and Interpolation Methods for Loop-Level Calculations

The need to approximate functions is ubiquitous in science, either due to empirical constraints or high computational cost of accessing the function. In high-energy physics, the precise computation of the scattering cross-section of a process requires the evaluation of computationally intensive integrals. A wide variety of methods in machine learning have been used to tackle this problem, but often the motivation of using one method over another is lacking. Comparing these methods is typically highly dependent on the problem at hand, so we specify to the case where we can evaluate the function a large number of times, after which quick and accurate evaluation can take place. We consider four interpolation and three machine learning techniques and compare their performance on three toy functions, the four-point scalar Passarino-Veltman $D_0$ function, and the two-loop self-energy master integral $M$. We find that in low dimensions ($d = 3$), traditional interpolation techniques like the Radial Basis Function perform very well, but in higher dimensions ($d=5, 6, 9$) we find that multi-layer perceptrons (a.k.a neural networks) do not suffer as much from the curse of dimensionality and provide the fastest and most accurate predictions.Comment: 30 pages, 17 figures, v2:added a few references, v3: new title, added a few reference

The Effect Of Ni And Cu Catalysts On The Growth Of Graphene Under Different Ethanol Flow Rates Using Atmospheric Pressure Chemical Vapor Deposition

Graphene was grown on both nickel (Ni) and copper (Cu) catalysts by atmospheric pressure chemical vapor deposition (APCVD) technique at various ethanol flow rates. Raman spectroscopy and field emission scanning electron microscopy (FESEM) were used to study morphological and structural properties of APCVD grown graphene. The crystallite size, defect intensity, distance between defects and the graphene thickness were estimated based on Raman spectra analysis. For the same growth conditions, Ni catalyst promote the formation of more graphene layers as compare to Cu. This because of the higher carbon solubility in Ni as compared to Cu which leads to different growth mechanisms

Contribution a l'analyse non-lineaire materielle et geometrique des coques en beton arme

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 80597 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Clinical Trials in Hepatopancreatobiliary Surgery: Assessing Trial Characteristics, Early Discontinuation, Result Reporting, and Publication

BACKGROUND: Hepatopancreaticobiliary (HPB) diseases carry high morbidity despite efforts aimed at their reduction. An assessment of their trial characteristics is paramount to determine trial design adequacy and highlight areas for improvement. As such, the aim of this study is to assess HPB surgery trial characteristics, summarize logistic, financial, and practical reasons behind early discontinuation, and propose potential interventions to prevent this in the future. METHODS: All clinical trials investigating HPB surgery registered on ClinicalTrials.gov from October 1st, 2007 (inclusive), to April 20th, 2021 (inclusive), were examined. Trial characteristics were collected including, but not limited to, study phase, duration, patient enrollment size, location, and study design. Peer-reviewed publications associated with the selected trials were also assessed to determine outcome reporting. RESULTS: A total of 1776 clinical trials conducted in 43 countries were identified, the majority of which were conducted in the USA. Of these trials, 32% were reported as completed whereas 12% were discontinued. The most common cause of trial discontinuation was low accrual, which was reported in 37% of terminated studies. These resulted in 413 published studies. Most trials had multiple assignment, randomized, or open-label designs. Treatment was the most common study objective (73%) with pharmacological therapy being the most commonly studied intervention. CONCLUSIONS: The main reasons for early discontinuation of clinical trials in HPB surgery are poor patient recruitment and inadequate funding. Improved trial design, recruitment strategies and increased funding are needed to prevent trial discontinuation and increase publication rates of HPB surgery clinical trials