A luminosity monitor for the A4 parity violation experiment at MAMI

A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both is required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 hours with electron beam, and the results of its application in the A4 experiment are presented.Comment: 22 pages, 12 figures, submitted to NIM

Strange nucleon form factors in the perturbative chiral quark model

We apply the perturbative chiral quark model at one loop to calculate the strange form factors of the nucleon. A detailed numerical analysis of the strange magnetic moments and radii of the nucleon, and also the momentum dependence of the form factors is presented.Comment: 18 pages, 6 figure

Unifying local-global type properties in vector optimization.

It is well-known that all local minimum points of a semistrictly quasiconvex real-valued function are global minimum points. Also, any local maximum point of an explicitly quasiconvex real-valued function is a global minimum point, provided that it belongs to the intrinsic core of the function’s domain. The aim of this paper is to show that these “local min - global min” and “local max - global min” type properties can be extended and unified by a single general localglobal extremality principle for certain generalized convex vector-valued functions with respect to two proper subsets of the outcome space. For particular choices of these two sets, we recover and refine several local-global properties known in the literature, concerning unified vector optimization (where optimality is defined with respect to an arbitrary set, not necessarily a convex cone) and, in particular, classical vector/multicriteria optimization.Nicolae Popovici’s research was supported by a grant of the Romanian Ministry of Research and Innovation, CNCS-UEFISCDI, project number PN-III-P4-ID-PCE- 2016-0190, within PNCDI III

Reasons for facebook usage: Data from 46 countries

Seventy-nine percent of internet users use Facebook, and on average they access Facebook eight times a day (Greenwood et al., 2016). To put these numbers into perspective, according to Clement (2019), around 30% of the world\u2019s population uses this Online Social Network (OSN) site. Despite the constantly growing body of academic research on Facebook (Chou et al., 2009; Back et al., 2010; Kaplan and Haenlein, 2010; McAndrew and Jeong, 2012; Wilson et al., 2012; Krasnova et al., 2017), there remains limited research regarding the motivation behind Facebook use across different cultures. Our main goal was to collect data from a large cross-cultural sample of Facebook users to examine the roles of sex, age, and, most importantly, cultural differences underlying Facebook use

Sex differences in mate preferences across 45 countries: A large-scale replication

Considerable research has examined human mate preferences across cultures, finding universal sex differences in preferences for attractiveness and resources as well as sources of systematic cultural variation. Two competing perspectives—an evolutionary psychological perspective and a biosocial role perspective—offer alternative explanations for these findings. However, the original data on which each perspective relies are decades old, and the literature is fraught with conflicting methods, analyses, results, and conclusions. Using a new 45-country sample (N = 14,399), we attempted to replicate classic studies and test both the evolutionary and biosocial role perspectives. Support for universal sex differences in preferences remains robust: Men, more than women, prefer attractive, young mates, and women, more than men, prefer older mates with financial prospects. Cross-culturally, both sexes have mates closer to their own ages as gender equality increases. Beyond age of partner, neither pathogen prevalence nor gender equality robustly predicted sex differences or preferences across countries

Martin-Luther-Universität Halle-Wittenberg Institut für Mathematik Relations Between Strictly Robust Optimization Problems and a Nonlinear Scalarization Method Relations Between Strictly Robust Optimization Problems and a Nonlinear Scalarization Method Re

Abstract. We study a strictly robust optimization problem in the context of a nonlinear scalarization method. We introduce a strictly robust multicriteria optimization problem and discuss its relation to a well-known scalar strictly robust optimization problem by using the nonlinear scalarization concept. Furthermore, we propose an unrestricted multicriteria optimization problem and note that its set of weakly Pareto optimal solutions contains all solutions of the scalar strictly robust optimization problem