The Period Changes of the Cepheid RT Aurigae

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit.Comment: Accepted for publication in PASP (November 2007

EVIDENCES OF SURFACE DIFFERENTIAL ROTATION ON THE RED DWARF PZ MON

Photometric behavior of the active red dwarf PZ Mori (K2e) is studied using UBVRI obser­vations obtained with 1.25 m telescope of the SRI "Crimean Astrophysical Observatory" in 1992-2004 and V-data from the ASAS catalogue obtained in 2000­2006. Frequency analysis of the full V-data and colors has shown the existence of close periods – 2429d and 2500 d, respectively. Supposing that the star's surface is covered by spots a long-term variability can be ex­plained as changes of stellar activity during 6.5 years. After subtraction of slow periodicity some periods in the range of 15 d  - 56 d with amplitudes more than 4a were found. Period P = 34d found as at the whole in­terval of observations as at the short selected intervals is likely close to the rotation period of the star. Steady-phase of this period indicates the existence of an active longitude where spots are generated.

V strane legend : legendy minuvsich vekov v pereskaze dlja detej / [pereskazali V. Markova ... Chudoznik: V. Zmeev]

V STRANE LEGEND : LEGENDY MINUVSICH VEKOV V PERESKAZE DLJA DETEJ / [PERESKAZALI V. MARKOVA ... CHUDOZNIK: V. ZMEEV] V strane legend : legendy minuvsich vekov v pereskaze dlja detej / [pereskazali V. Markova ... Chudoznik: V. Zmeev] (1) Einband (1) Titelblatt (10) K junym citateljam (12) Poslednij boj rolanda (14) Illustration (15) Korol' Artur i rycari kruglogo ctola (28) Illustration (29) Tristan i Isol'da (62) Illustration (63) Loengrin (84) Illustration (85) Robin Gud (94) Illustration (95) Tomas Lermont (116) Illustration (117) Loreleja (130) Illustration (131) Gamel'nskij krycolov (138) Illustration (139) Vil'gel'm Tell' (150) Illustration (151) Don Zuan (160) Illustration (161) "Letucij Gollandec" (172) Illustration (173) Doktor Faust (180) Illustration (181) Primecanija (210) Soderzanie (231) Impressum (232

[DNA replication in intact and X-ray-irradiated cells in the Cockayne syndrome.

Using DNA fiber autoradiography, an estimation was made of DNA replication in normal fibroblasts and in those derived from a patient with Cockayne syndrome. The rate of replication fork movement as well as the rate of DNA chain growth, dependent on the frequency of initiation sites in the adjacent clusters of replicons, did not differ in Cockayne syndrome cells, compared to cells of normal donors, either before or after exposure to ionizing radiation