Statistical estimates of the<tex>n</tex>-bit Gray codes by restricted random generation of permutations of 1 to<tex>2^n</tex>

1983 ◽  
Vol 29 (6) ◽  
pp. 894-901 ◽  
Author(s):  
J. Silverman ◽  
V. Vickers ◽  
J. Sampson
Author(s):  
Sergey Kovalenko

The management of surface watercourses is an urgent scientific task. The article presents the results of statistical processing of long-term monthly data of field observations of hydrological and hydrochemical parameters along the Upper Yerga small river in the Vologda region. Sampling estimates of statistical parameters are obtained, autocorrelation and correlation analyzes are performed. The limiting periods from the point of view of pollution for water receivers receiving wastewater from drained agricultural areas are identified.


Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 8
Author(s):  
Alessandro Montoli ◽  
Marco Antonelli ◽  
Brynmor Haskell ◽  
Pierre Pizzochero

A common way to calculate the glitch activity of a pulsar is an ordinary linear regression of the observed cumulative glitch history. This method however is likely to underestimate the errors on the activity, as it implicitly assumes a (long-term) linear dependence between glitch sizes and waiting times, as well as equal variance, i.e., homoscedasticity, in the fit residuals, both assumptions that are not well justified from pulsar data. In this paper, we review the extrapolation of the glitch activity parameter and explore two alternatives: the relaxation of the homoscedasticity hypothesis in the linear fit and the use of the bootstrap technique. We find a larger uncertainty in the activity with respect to that obtained by ordinary linear regression, especially for those objects in which it can be significantly affected by a single glitch. We discuss how this affects the theoretical upper bound on the moment of inertia associated with the region of a neutron star containing the superfluid reservoir of angular momentum released in a stationary sequence of glitches. We find that this upper bound is less tight if one considers the uncertainty on the activity estimated with the bootstrap method and allows for models in which the superfluid reservoir is entirely in the crust.


2019 ◽  
Vol 32 (5) ◽  
pp. 439-445 ◽  
Author(s):  
Mohammad Aghaali ◽  
Seyed Saeed Hashemi-Nazari

Abstract Background Recent studies have shown that antibiotic exposure during infancy is associated with increased body mass in healthy children. This study was performed to investigate the association between early-life antibiotic exposure and risk of childhood obesity. Methods A systematic review and meta-analysis was performed to comprehensively and quantitatively determine the association between early antibiotic exposure and risk of childhood obesity. Various databases such as PubMed, Embase, Scopus, Web of Science, ProQuest, Cochrane and Google Scholar were searched. A random-effects meta-analysis was performed to pool the statistical estimates. Additionally, a subgroup analysis was performed based on the time of follow-up. Results Nineteen studies involving at least 671,681 participants were finally included. Antibiotic exposure in early life was significantly associated with risk of childhood weight gain and obesity (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.04–1.06). Conclusions Antibiotic exposure in early life significantly increases the risk of childhood weight gain and obesity.


Information ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Alexey Semenkov ◽  
Dmitry Bragin ◽  
Yakov Usoltsev ◽  
Anton Konev ◽  
Evgeny Kostuchenko

Modern facial recognition algorithms make it possible to identify system users by their appearance with a high level of accuracy. In such cases, an image of the user’s face is converted to parameters that later are used in a recognition process. On the other hand, the obtained parameters can be used as data for pseudo-random number generators. However, the closeness of the sequence generated by such a generator to a truly random one is questionable. This paper proposes a system which is able to authenticate users by their face, and generate pseudo-random values based on the facial image that will later serve to generate an encryption key. The generator of a random value was tested with the NIST Statistical Test Suite. The subsystem of image recognition was also tested under various conditions of taking the image. The test results of the random value generator show a satisfactory level of randomness, i.e., an average of 0.47 random generation (NIST test), with 95% accuracy of the system as a whole.


1979 ◽  
Vol 57 (2) ◽  
pp. 117-124 ◽  
Author(s):  
J. J. Myher ◽  
A. Kuksis

A method of simultaneous determination of stereospecific distribution and molecular association of acyl groups in triacylglycerols has been developed. The analysis is based on a random generation of rac-1, 2-diacylglycerols by Grignard degradation, synthesis of rac-phosphatidylcholines, and a stereospecific stepwise release of 1, 2-sn- and 2, 3-sn-diacylglycerols by phospholipase C. The exact structure of the original triacylglycerols is reconstituted on the basis of complete analysis of the molecular species of the 1, 2-sn- and 2, 3-sn-diacylglycerols as the tertiary-butyldimethylsilyl ethers by gas chromatography with mass spectrometry. The validity of the method is demonstrated by analyses of synthetic triacylglycerols of known structure. A practical application is illustrated by determination of the fatty acid distribution in lard.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
José R. Rossari ◽  
Otto Metzger-Filho ◽  
Marianne Paesmans ◽  
Kamal S. Saini ◽  
Alessandra Gennari ◽  
...  

Background. Randomized studies have shown different magnitude of bevacizumab benefit in the treatment of advanced breast cancer. Regulatory agencies have modified bevacizumab treatment indications across different regions. In this study, we perform a meta-analysis of phase III studies aiming to interrogate the magnitude of bevacizumab benefit for the treatment of first-line HER2-negative metastatic breast cancer (MBC).Methods. Data from studies E2100, AVADO and RIBBON-1 were used to calculate the benefit of bevacizumab in terms of tumor overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and toxicities. Combined statistical estimates of hazard ratios (HR) and odds ratios were calculated using fixed-effects or random-effects models.Results. A total of 2,695 patients were evaluated. Combining bevacizumab with different chemotherapy backbones resulted in a 30% risk reduction of PFS events (HR = 0.70; 95% confidence interval [CI], 0.57–0.86) and increased ORR (odds ratio 1.81; 95% CI, 1.53–2.14). No OS benefit could be demonstrated (HR = 0.95; 95% CI, 0.85–1.06). Bevacizumab significantly increased the incidence of adverse events such as proteinuria, hypertension and cardiovascular events.Conclusions. Bevacizumab combined with chemotherapy in the first-line treatment of MBC significantly improved ORR and PFS, but also increased grade 3-4 toxicities. No significant OS advantage was observed.


2016 ◽  
Vol 10 (1) ◽  
pp. 78-85 ◽  
Author(s):  
I. S. Bykov
Keyword(s):  

2021 ◽  
Vol 5 (1) ◽  
pp. 19
Author(s):  
Alexander Kushnir ◽  
Alexander Varypaev

The publication is devoted to studying asymptotic properties of statistical estimates of the distribution parameters u∈Rq of a multidimensional random stationary time series zt∈Rm, t∈ℤ satisfying the strong mixing conditions. We consider estimates u^nδ(z¯n), z¯n=(z1T,…,znT)T∈Rmn that provide in asymptotic n→∞ the maximum values for some objective functions Qn(z¯n;u), which have properties similar to the well-known property of local asymptotic normality. These estimates are constructed by solving the equations δn(z¯n;u)=0, where δn(z¯n;u) are arbitrary functions for which δn(z¯n;u)−gradhQn(z¯n;u+n−1/2h)→0(n→∞) in Pn,u(z¯n)-probability uniformly on u∈U, were U is compact in Rq. In many cases, the estimates u^nδ(z¯n) have the same asymptotic properties as well-known M-estimates defined by equations u^nQ(z¯n)=arg maxu∈UQn(z¯n;u) but often can be much simpler computationally. We consider an algorithmic method for constructing estimates u^nδ(z¯n), which is similar to the accumulation method first proposed by R. Fischer and rigorously developed by L. Le Cam. The main theoretical result of the article is the proof of the theorem, in which conditions of the asymptotic normality of estimates u^nδ(z¯n) are formulated, and the expression is proposed for their matrix of asymptotic mean-square deviations limn→∞nEn,u{(u^δ(z¯n)−u)(u^δ(z¯n)−u)T}.


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