Answer to a question of Kolmogorov

More than 80 years ago Kolmogorov asked the following question. Let E ⊆ R 2 E\subseteq \mathbb {R}^{2} be a measurable set with λ 2 ( E ) &gt; ∞ \lambda ^{2}(E)&gt;\infty , where λ 2 \lambda ^2 denotes the two-dimensional Lebesgue measure. Does there exist for every ε &gt; 0 \varepsilon &gt;0 a contraction f : E → R 2 f\colon E\to \mathbb {R}^{2} such that λ 2 ( f ( E ) ) ≥ λ 2 ( E ) − ε \lambda ^{2}(f(E))\geq \lambda ^{2}(E)-\varepsilon and f ( E ) f(E) is a polygon? We answer this question in the negative by constructing a bounded, simply connected open counterexample. Our construction can easily be modified to yield an analogous result in higher dimensions.</p

The Relation of Occupational Identity, and Family Background Variables in a Hungarian Sample of Emerging Adults

Background: In the last few decades, identity formation has been postponed until the mid or late twenties (ARNETT 2000). ARNETT calls this specific period between 19–27 emerging adulthood. According to WATERMAN (1999), some family variables can foster or hinder the process of identity development. In our study, we investigate the relation of parenting styles described by BAUMRIND (1991), two-parent or one-parent family backgrounds, and occupational identity. Among the dimensions of identity, we will focus on occupational identity, since it has great importance in this period of life. Method: Besides demographic variables and data regarding the participants’ family background, we used the Melgosa Occupational Identity Scale (OIS), Parental Authority Questionnaire (PAQ). The sample consisted of 220 19–29-year-old emerging adults. Results: According to our hypothesis, identity diffusion and moratorium show a slightly negative correlation with age. Regarding occupational identity, it seems significant whether the person could or could not find a job in accordance with their qualifications: the moratorium is higher among those who could not, while foreclosure and identity achievement is higher among those who found a job in their professional field. Regarding family background, it seems that children of divorced parents do now show higher rates of less adaptive identity statuses, but foreclosure is higher among children raised in two-parent families. Conforming to our expectations, we found that permissive parenting is related to identity diffusion, while interestingly, both the father’s and the mother’s authoritative parenting is related to foreclosure

Precise half-life measurement of 110Sn and 109In isotopes

The half-lives of 110Sn and 109In isotopes have been measured with high precision. The results are T1/2 =4.173 +- 0.023 h for 110Sn and T1/2 = 4.167 +-0.018 h for 109In. The precision of the half-lives has been increased by a factor of 5 with respect to the literature values which makes results of the recently measured 106Cd(alpha,gamma)110Sn and 106Cd(alpha,p)109In cross sections more reliable.Comment: 3 pages, 2 figures, accepted for publication in Phys. Rev C as brief repor

High precision 89^{89}Y(α\alpha,α\alpha)89^{89}Y scattering at low energies

Elastic scattering cross sections of the $^{89}$Y($\alpha$,$\alpha$)$^{89}$Y reaction have been measured at energies E$_{c.m.}$ = 15.51 and 18.63 MeV. The high precision data for the semi-magic $N = 50$ nucleus $^{89}$Y are used to derive a local potential and to evaluate the predictions of global and regional $\alpha$-nucleus potentials. The variation of the elastic alpha scattering cross sections along the $N = 50$ isotonic chain is investigated by a study of the ratios of angular distributions for $^{89}$Y($\alpha$,$\alpha$)$^{89}$Y and $^{92}$Mo($\alpha$,$\alpha$)$^{92}$Mo at E$_{c.m.} \approx$ 15.51 and 18.63 MeV. This ratio is a very sensitive probe at energies close to the Coulomb barrier, where scattering data alone is usually not enough to characterize the different potentials. Furthermore, $\alpha$-cluster states in $^{93}$Nb = $^{89}$Y $\otimes$ $\alpha$ are investigated

Response of Multi-strip Multi-gap Resistive Plate Chamber

A prototype of Multi-strip Multi-gap Resistive Plate chamber (MMRPC) with active area 40 cm $\times$ 20 cm has been developed at SINP, Kolkata. Detailed response of the developed detector was studied with the pulsed electron beam from ELBE at Helmholtz-Zentrum Dresden-Rossendorf. In this report the response of SINP developed MMRPC with different controlling parameters is described in details. The obtained time resolution ($\sigma_t$) of the detector after slew correction was 91.5$\pm$3 ps. Position resolution measured along ($\sigma_x$) and across ($\sigma_y$) the strip was 2.8$\pm$0.6 cm and 0.58 cm, respectively. The measured absolute efficiency of the detector for minimum ionizing particle like electron was 95.8$\pm$1.3 $\%$. Better timing resolution of the detector can be achieved by restricting the events to a single strip. The response of the detector was mainly in avalanche mode but a few percentage of streamer mode response was also observed. A comparison of the response of these two modes with trigger rate was studiedComment: 19 pages, 26 figure

Presence of stolbur phytoplasma in Cixiidae in Hungarian vineyards

Bois Noir (16SrXII-A) phytoplasmas were identified in three viticultural areas of Hungary in 18 % of Hyalesthes obsoletus, and in an asymptomatic nettle sample. The cixiid Reptalus panzeri was found to be infected with 16SrXII-A and with 16SrIII (X-disease) phytoplasmas. The latter pathogen was also detected in symptomatic wild Cirsium spp. and Convolvolus collected inside Bois Noir-infected and R. panzeri-infested vineyards

Efficiency determination of resistive plate chambers for fast quasi-monoenergetic neutrons

Composite detectors made of stainless steel converters and multigap resistive plate chambers have been irradiated with quasi-monoenergetic neutrons with a peak energy of 175MeV. The neutron detection efficiency has been determined using two different methods. The data are in agreement with the output of Monte Carlo simulations. The simulations are then extended to study the response of a hypothetical array made of these detectors to energetic neutrons from a radioactive ion beam experiment.Comment: Submitted to Eur.Phys.J. A; upgraded version correcting some typos and updating ref.

Psychoactive substance use and problematic Internet use as predictors of bullying and cyberbullying victimization

Research exploring the relationship between addictions and experiences of bullying suggests that problem behaviors may generally be associated with an increased risk of victimization. The aim of the present study was to examine the role of psychoactive substance use, excessive Internet use, and social support in both traditional offline bullying and online Bcyberbullying^ victimization in a nationally representative sample of adolescents (N = 6237; 51% male; Mage = 16.62 years, SD = 0.95). Results demonstrated that traditional bullying victimization was associated with cyberbullying victimization. Furthermore, psychoactive substance use and problematic Internet use predicted both traditional bullying and cyberbullying victimization. Finally, perceived social support was found to be an important protective factor against both traditional and cyberbullying victimization. However, psychoactive substance use and problematic Internet use accounted for only a small proportion of variance in victimization

Elastic and total reaction cross sections of oxygen isotopes in Glauber theory

We systematically calculate the total reaction cross sections of oxygen isotopes, $^{15-24}$O, on a $^{12}$C target at high energies using the Glauber theory. The oxygen isotopes are described with Slater determinants generated from a phenomenological mean-field potential. The agreement between theory and experiment is generally good, but a sharp increase of the reaction cross sections from ^{21}O to ^{23}O remains unresolved. To examine the sensitivity of the diffraction pattern of elastic scattering to the nuclear surface, we study the differential elastic-scattering cross sections of proton-^{20,21,23}O at the incident energy of 300 MeV by calculating the full Glauber amplitude.Comment: 9 pages, 8 figure