The luminosity-redshift relation in brane-worlds: I. Analytical results

The luminosity distance - redshift relation is analytically given for generalized Randall-Sundrum type II brane-world models containing dark radiation. The derived expressions contain both elementary functions and elliptic integrals of the first and second kind. First we derive the relation for models with the Randall-Sundrum fine-tuning. Then we generalize the method for models with cosmological constant. The analytical results are suitable for testing brane-world models when future supernova data at higher redshifts will be available.Comment: v2: Improved discussion and new references; analytical results kept, comparison with observation moved to astro-ph/0702610, 18 pages, 2 figures v3: Minor improvements, few new references. Version to appear in the initial issue of PMC Physics

Large size and slow rotation of the trans-Neptunian object (225088) 2007 OR10 discovered from Herschel and K2 observations

We present the first comprehensive thermal and rotational analysis of the second most distant trans-Neptunian object (225088) 2007 OR10. We combined optical light curves provided by the Kepler space telescope -- K2 extended mission and thermal infrared data provided by the Herschel Space Observatory. We found that (225088) 2007 OR10 is likely to be larger and darker than derived by earlier studies: we obtained a diameter of d=1535^{+75}_{-225} km which places (225088) 2007 OR10 in the biggest top three trans-Neptunian objects. The corresponding visual geometric albedo is p_V=0.089^{+0.031}_{-0.009}. The light curve analysis revealed a slow rotation rate of P_rot=44.81+/-0.37 h, superseded by a very few objects only. The most likely light-curve solution is double-peaked with a slight asymmetry, however, we cannot safely rule out the possibility of having a rotation period of P_rot=22.40+/-0.18 h which corresponds to a single-peaked solution. Due to the size and slow rotation, the shape of the object should be a MacLaurin ellipsoid, so the light variation should be caused by surface inhomogeneities. Its newly derived larger diameter also implies larger surface gravity and a more likely retention of volatiles -- CH_4, CO and N_2 -- on the surface.Comment: Accepted for publication in AJ, 8 pages in emulateapj styl

An ab initio and DFT conformational analysis of unsubstituted and omega-substituted ethyl-benzene: (Ph-CH2-CH2-Z; Z = -H, -F, -NH3+, -CH3)

A series of compounds of Ph-CH2-CH2-Z, with substituents Z = -H, -F, -NH3+-, and -CH3, were subjected to conformational analysis. Conformational potential energy surfaces were generated and their minima were geometrically optimized at three levels of theory. The relative stabilities of the minima correlated with the electron withdrawing nature of the substituents (Z). (C) 2002 Elsevier Science B.V. All rights reserved

Rotational Properties of Hilda Asteroids Observed by the K2 Mission

Hilda asteroids orbit at the outer edge, or just outside of the Main Belt, occupying the 2:3 mean motion resonance with Jupiter. It is known that the group shows a mixed taxonomy that suggests the mixed origin of Hilda members, having migrated to the current orbit both from the outer Main Belt and from the Trojans swarms. But there are still few observations for comparative studies that help in understanding the Hilda group in deeper details. We identified 125 individual light curves of Hilda asteroids observed by the K2 mission. We found that despite of the mixed taxonomies, the Hilda group highly resembles to the Trojans in the distribution of rotation periods and amplitudes, and even the LR group (mostly C and X-type) Hildas follow this rule. Contrary to the Main Belt, Hilda group lacks the very fast rotators. The ratio of extremely slow rotators (P>100 h) is a surprising 18%, which is unique in the Solar System. The occurrence rate of asteroids with multiple periods (4%) and asteroids with three maxima in the light curves (5%) can be signs of high rate of binarity, which we can estimate as 25% within the Hilda group

Can NO2+ exist in bent or cyclic forms?

Calculations of NO2+ at HF, CBS-4, CASSCF, MBPT(2), MBPT(3), and MBPT(4) theory levels, using 3-21G and 6-31G(d) basis sets, found two C-2V structures along with the linear geometry. Computations using MBPT(2) and CCSD(T) approaches and the aug-cc-pvtz basis set confirmed these results. Harmonic vibrational frequency calculations, performed with MBPT(2) and CCSD(T) theories, indicated that the linear structure was the global minimum while one of the bent structures (angle ONO = 80 degrees) was a higher energy local minimum. The second C-2V structure (angle ONO = 45 degrees) exhibited a large imaginary vibrational frequency along the asymmetric stretching (B-2) mode, indicating its saddle point nature. (C) 2001 Elsevier Science B.V. All rights reserved

The slow component of the delayed rectifier potassium current in undiseased human ventricular myocytes

Objective: The purpose of this study was to investigate the properties of the slow component of the delayed rectifier potassium current (I-Ks) in myocytes isolated from undiseased human left ventricles. Methods: The whole-cell configuration of the patch-clamp technique was applied in 58 left ventricular myocytes from 15 hearts at 37 degreesC. Nisoldipine (1 muM) was used to block inward calcium current (I-Ca) and E-4031 (1-5 muM) was applied to inhibit the rapid component of the delayed rectifier potassium current (I-Ks). Results: In 31 myocytes an E-4031 insensitive, but L-735,821 and chromanol 293B sensitive, tail current was identified which was attributed to the slow component of I-K (I-Ks). Activation of I-Ks was slow (tau = 903 +/- 101 ms at 50 mV, n = 24), but deactivation of the current was relatively rapid ( tau =122.4 +/- 11.7 ms at -40 mV, n = 19). The activation of I-Ks was voltage independent but its deactivation showed clear voltage dependence. The deactivation was faster at negative voltages (about 100 ms at -50 mV) and slower at depolarized potentials (about 300 ms at 0 mV). In six cells, the reversal potential was -81.6 +/- 2.8 mV on an average which is close to the K+ equilibrium potential suggesting K+ as the main charge carrier. Conclusion: In undiseased human ventricular myocytes, I-Ks exhibits slow activation and fast deactivation kinetics. Therefore, in humans I-Ks differs from that reported in guinea pig, and it best resembles I-Ks described in dog and rabbit ventricular myocytes

The Vartian Collection Part IV. : Geometridae

A bécsi Naturhistorisches Museum lepkegyűjteményében őrzött Eva Vartian-féle gyűjtemény araszolólepke (Geometridae) anyagának tételes feldolgozása. A gyűjteményrész 1353 Geometridae taxon több mint 22000 példányából áll. A könyv ennek a gyűjteményrésznek taxonómiai és biogeográfiai elemzését (beleértve 6 a tudományra nézve új faj leírását), a tételes fajjegyzéket és valamennyi faj és alfaj természetes nagyságú színes képeit (összesen 87 színes táblán) tartalmazza