Small violations of full correlation Bell inequalities for multipartite pure random states

We estimate the probability of random $N$-qudit pure states violating full-correlation Bell inequalities with two dichotomic observables per site. These inequalities can show violations that grow exponentially with $N$, but we prove this is not the typical case. For many-qubit states the probability to violate any of these inequalities by an amount that grows linearly with $N$ is vanishingly small. If each system's Hilbert space dimension is larger than two, on the other hand, the probability of seeing \emph{any} violation is already small. For the qubits case we discuss furthermore the consequences of this result for the probability of seeing arbitrary violations (\emph i.e., of any order of magnitude) when experimental imperfections are considered.Comment: 16 pages, one colum

Phase space measure concentration for an ideal gas

We point out that a special case of an ideal gas exhibits concentration of the volume of its phase space, which is a sphere, around its equator in the thermodynamic limit. The rate of approach to the thermodynamic limit is determined. Our argument relies on the spherical isoperimetric inequality of L\'{e}vy and Gromov.Comment: 15 pages, No figures, Accepted by Modern Physics Letters

Torsional nodeless vibrations of quaking neutron star restored by combined forces of shear elastic and magnetic field stresses

Within the framework of Newtonian magneto-solid-mechanics, relying on equations appropriate for a perfectly conducting elastic continuous medium threaded by a uniform magnetic field, the asteroseismic model of a neutron star undergoing axisymmetric global torsional nodeless vibrations under the combined action of Hooke's elastic and Lorentz magnetic forces is considered with emphasis on a toroidal Alfv\'en mode of differentially rotational vibrations about the dipole magnetic moment axis of the star. The obtained spectral equation for frequency is applied to $\ell$-pole identification of quasi-periodic oscillations (QPOs) of X-ray flux during the giant flares of SGR 1806-20 and SGR 1900+14. Our calculations suggest that detected QPOs can be consistently interpreted, within the framework of this model, as produced by global torsional nodeless vibrations of quaking magnetar if they are considered to be restored by the joint action of bulk forces of shear elastic and magnetic field stresses.Comment: 18 pages, 5 figures; accepted in Ap

Conditional Targeting of the DNA Repair Enzyme hOGG1 into Mitochondria

Oxidative damage to mitochondrial DNA (mtDNA) has been suggested to be a key factor in the etiologies of many diseases and in the normal process of aging. Although the presence of a repair system to remove this damage has been demonstrated, the mechanisms involved in this repair have not been well defined. In an effort to better understand the physiological role of recombinant 8-oxoguanine DNA glycosylase/apurinic lyase (OGG1) in mtDNA repair, we constructed an expression vector containing the gene for OGG1 downstream of the mitochondrial localization sequence from manganese-superoxide dismutase. This gene construct was placed under the control of a tetracycline-regulated promoter. Transfected cells that conditionally expressed OGG1 in the absence of the tetracycline analogue doxycycline and targeted this recombinant protein to mitochondria were generated. Western blots of mitochondrial extracts from vector- and OGG1-transfected clones with and without doxycycline revealed that removal of doxycycline for 4 days caused an approximate 8-fold increase in the amount of OGG1 protein in mitochondria. Enzyme activity assays and DNA repair studies showed that the doxycycline-dependent recombinant OGG1 is functional. Functional studies revealed that cells containing recombinant OGG1 were more proficient at repairing oxidative damage in their mtDNA, and this increased repair led to increased cellular survival following oxidative stress

Discovery of a Perseus-like cloud in the early Universe: HI-to-H2 transition, carbon monoxide and small dust grains at zabs=2.53 towards the quasar J0000+0048

We present the discovery of a molecular cloud at zabs=2.5255 along the line of sight to the quasar J0000+0048. We perform a detailed analysis of the absorption lines from ionic, neutral atomic and molecular species in different excitation levels, as well as the broad-band dust extinction. We find that the absorber classifies as a Damped Lyman-alpha system (DLA) with logN(HI)(cm^-2)=20.8+/-0.1. The DLA has super-Solar metallicity with a depletion pattern typical of cold gas and an overall molecular fraction ~50%. This is the highest f-value observed to date in a high-z intervening system. Most of the molecular hydrogen arises from a clearly identified narrow (b~0.7 km/s), cold component in which CO molecules are also found, with logN(CO)~15. We study the chemical and physical conditions in the cold gas. We find that the line of sight probes the gas deep after the HI-to-H2 transition in a ~4-5 pc-size cloud with volumic density nH~80 cm^-3 and temperature of only 50 K. Our model suggests that the presence of small dust grains (down to about 0.001 {\mu}m) and high cosmic ray ionisation rate (zeta_H a few times 10^-15 s^-1) are needed to explain the observed atomic and molecular abundances. The presence of small grains is also in agreement with the observed steep extinction curve that also features a 2175 A bump. The properties of this cloud are very similar to what is seen in diffuse molecular regions of the nearby Perseus complex. The high excitation temperature of CO rotational levels towards J0000+0048 betrays however the higher temperature of the cosmic microwave background. Using the derived physical conditions, we correct for a small contribution (0.3 K) of collisional excitation and obtain TCMB(z = 2.53)~9.6 K, in perfect agreement with the predicted adiabatic cooling of the Universe. [abridged]Comment: 24 pages, 24 figures, accepted for publication in A&

Effects of school quality, school citizenship policy, and student body composition on the acquisition of citizenship competences in the final year of primary education

This study examines the effects of general educational quality of schools, school citizenship policy, and ethnic homogeneity of the student body on the acquisition of citizenship competences in the final year of primary education. The theoretical framework is based on developmental, psychological, and sociological studies into effects of social context on educational outcomes and research into effective schools. The effects of school quality, school policy, and student population were analysed using 2-level (students, school) multilevel models. The results show that differences in citizenship competences between students and schools are mainly explained by factors at student level. Although the school also appeared to play a role, the school variables used in the analysis did not offer sufficient explanation for these differences. In order to further investigate the relationship between school factors and students’ citizenship, more insight is needed into characteristics of citizenship practices of schools

Photometric Monitoring of the Gravitationally Lensed Ultraluminous BAL Quasar APM08279+5255

We report on one year of photometric monitoring of the ultraluminous BAL quasar APM 08279+5255. The temporal sampling reveals that this gravitationally lensed system has brightened by ~0.2 mag in 100 days. Two potential causes present themselves; either the variability is intrinsic to the quasar, or it is the result of microlensing by stars in a foreground system. The data is consistent with both hypotheses and further monitoring is required before either case can be conclusively confirmed. We demonstrate, however, that gravitational microlensing can not play a dominant role in explaining the phenomenal properties exhibited by APM 08279+5255. The identification of intrinsic variability, coupled with the simple gravitational lensing configuration, would suggest that APM 08279+5255 is a potential golden lens from which the cosmological parameters can be derived and is worthy of a monitoring program at high spatial resolution.Comment: 17 pages, with 2 figures. Accepted for publication in P.A.S.

Yeast apurinic/apyrimidinic endonuclease Apn1 protects mammalian neuronal cell line from oxidative stress

Reactive oxygen species (ROS) have been implicated as one of the agents responsible for many neurodegenerative diseases. A critical target for ROS is DNA. Most oxidative stress-induced DNA damage in the nucleus and mitochondria is removed by the base excision repair pathway. Apn1 is a yeast enzyme in this pathway which possesses a wider substrate specificity and greater enzyme activity than its mammalian counterpart for removing DNA damage, making it a good therapeutic candidate. For this study we targeted Apn1 to mitochondria in a neuronal cell line derived from the substantia nigra by using a mitochondrial targeting signal (MTS) in an effort to hasten the removal of DNA damage and thereby protect these cells. We found that following oxidative stress, mitochondrial DNA (mtDNA) was repaired more efficiently in cells containing Apn1 with the MTS than controls. There was no difference in nuclear repair. However, cells that expressed Apn1 without the MTS showed enhanced repair of both nuclear and mtDNA. Both Apn1-expressing cells were more resistant to cell death following oxidative stress compared with controls. Therefore, these results reveal that the expression of Apn1 in neurons may be of potential therapeutic benefit for treating patients with specific neurodegenerative diseases