Metrologically useful states of spin-1 Bose condensates with macroscopic magnetization

We study theoretically the usefulness of spin-1 Bose condensates with macroscopic magnetization in a homogeneous magnetic field for quantum metrology. We demonstrate Heisenberg scaling of the quantum Fisher information for states in thermal equilibrium. The scaling applies to both antiferromagnetic and ferromagnetic interactions. The effect preserves as long as fluctuations of magnetization are sufficiently small. Scaling of the quantum Fisher information with the total particle number is derived within the mean-field approach in the zero temperature limit and exactly in the high magnetic field limit for any temperature. The precision gain is intuitively explained owing to subtle features of the quasi-distribution function in phase space.Comment: 9 pages, 5 figure

Spin-squeezed atomic crystal

We propose a method to obtain a regular arrangement of two-level atoms in a three-dimensional optical lattice with unit filling, where all the atoms share internal state coherence and metrologically useful quantum correlations. Such a spin-squeezed atomic crystal is obtained by adiabatically raising an optical lattice in an interacting two-component Bose-Einstein condensate. The scheme could be directly implemented on a microwave transition with state-of-the art techniques and used in optical-lattice atomic clocks with bosonic atoms to strongly suppress the collisional shift and benefit from the spins quantum correlations at the same time

Study of the phase transition in polycrystalline (Ba_{0.90}Pb_{0.10})(Ti_{0.90}Sn_{0.10})O_3

Polycrystalline sample of (Ba_{0.90}Pb_{0.10})(Ti_{0.90}Sn_{0.10})O_3 was obtained by means of a conventional ceramic technology. The dielectric measurements were performed depending on temperature and frequency of electric measuring field. The character of the phase transitions of (Ba_{0.90}Pb_{0.10})(Ti_{0.90}Sn_{0.10})O_3 ceramics strongly depends on the presence of Pb in the sample. The obtained results pointed out the diffused character of phase transition. The temperature dependence of the dielectric properties showed that the phase transition from the paraelectric phase to ferroelectric one takes place at the same temperature (T_{m}=367 K). It does not depend on the frequency of the measuring electric field. A change of the value of the parameter \gamma takes place in the paraelectric phase.Comment: 5 pages, 6 figure

Learning to educate : the comparison of the present-day condition of colleges in Poland with the past (case study)

The paper presents opinions of two persons: a 60-year-old teacher with long years of practice in both secondary and higher levels of education, worried with the condition of the Polish education, and a young researcher who has the results of specific empirical studies conducted in the environment of pedagogy students, who had the opportunity to compare the conclusions of his older colleague with his own. Both authors believe that at present, at the time of another reform of the Polish education, which started, as we know, with liquidation of gymnasia, it is important to come back to the causes why the Polish secondary and higher education system in the second decade of the 21st century is in the condition that requires deep changes; however, they are first of all interested in the future

Genetic constitution of parthenogenetic form of Polydrusus inustus (Coleoptera: Curculionidae) : hints of hybrid origin and recombinations

Asexual reproduction among insects may arise spontaneously, as a result of infectious agents or hybridization between phylogenetically distinct organisms. Polyploidy, which may be the result of auto- or allopoliploidization (also associated with hybridization), is often connected with parthenogenesis. However, all studied parthenogens of weevils were apomictic, rare meiotic stages have been observed in a few of them what could suggests in their genomes besides the mutational changeability also recombination may occurs. We studied the level of heterozygosity in Internal Transcribed Spacer 2 sequences, and congruence of mitochondrial (cytochrome B) and nuclear genealogies among individuals of parthenogenetic form of Polydrusus inustus. High frequency (87.0%) of heterozygotes in ITS2 sequences may indicate a hybrid origin of the parthenogen. It is possible that this parthenogenetic form arose via a hybridization event between phylogenetically distinct lineages of bisexual P. inustus, known only from Georgia and Turkey, or between this species and one of the closely relatives from the subgenus Scythodrusus. Although result of partition- homogeneity test did not show significant incongruence of mitochondrial and nuclear genealogies, in the network was detected one loop. Most probable explanations for existence of that loop in parthenogenetic form and for origin of rare homozygotes, which were detected in ITS2 sequences, is gene conversion. It is supported by recently cytogenetic studies indicating rare meiotic stages during the oogenesis of triploids of P. inustus

Restricted geographic distribution and low genetic distinctiveness of steppic Crioceris quinquepunctata (Coleoptera: Chrysomelidae) populations in Central East Europe

Crioceris quinquepunctata is a European leafbeetle, rare and strictly associated with steppe-like habitats in Central and Eastern Europe. We sampled suitable localities in Central East Europe to determine the current distribution and to verify whether populations isolated by the Carpathian Mountains (within Pannonian and Pontic area) show genetic differentiation. Sequences from the beetle COI and ITSl were amplified and compared. Furthermore, ftsZ and hcpA genes of the endosymbiont Wolbachia were analysed as additional genetic markers. We found only two populations of C. quinquepunctata (in Moravia and Podolian Upland). Unusually low genetic differences between these populations were revealed, which is in contrast to previous studies on other steppe beetles. The reasons for such low diversity are speculative and probably related to recent natural expansion or man-made translocation of C. quinquepunctata