The optical module of the Baikal deep underwater neutrino telescope

A deep underwater Cherenkov telescope has been operating since 1993 in stages of growing size at 1.1 km depth in Lake Baikal. The key component of the telescope is the Optical Module (OM) which houses the highly sensitive phototube QUASAR-370. We describe design and parameters of the QUASAR-370, the layout of the optical module, the front-end electronics and the calibration procedures, and present selected results from the five-year operation underwater. Also, future developments with respect to a telescope consisting from several thousand OMs are discussed.Comment: 30 pages, 24 figure

Status of the Lake Baikal Experiment

We review the present status of the Baikal Underwater Neutrino Experiment and report on neutrino events recorded with the detector stages NT-36 and NT-96.Comment: 5 pages, 4 PostScript figures, uses here.sty and mine.sty, submitted to the Proc. of 5th Int. Workshop on Topics in Astroparticle and Underground Physics (LNGS INFN, Assergi, September 7-11, 1997

ЭТНИЧЕСКИЕ АСПЕКТЫ НАСЛЕДСТВЕННОГО РАКА МОЛОЧНОЙ ЖЕЛЕЗЫ В РЕГИОНЕ СИБИРИ

Background: Ethnic diversity of the population in the region of Siberia suggests the existence of different germline mutations in the BRCA1/2 genes associated with breast and ovarian cancer in different ethnic populations, but spectrum of these mutations has not been studied. Objective: Our aim was to evaluate the frequency of the most common mutations BRCA1 / 2 (BRCA1 5382insC, BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT) in women diagnosed with breast cancer among indigenous people and newcomers living in Siberia. Methods: We tested 1281 genomic DNA samples for the presence of BRCA1 5382insC mutation in patients diagnosed with breast cancer considering no family history. 72 patients having hereditary cancer signs were tested for the mutations BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT. Results: Out of 765 patients of Slavic ethnic group, 27 women (3.5%) were carriers of allele BRCA1 5382insC. The frequencies of mutations in patients with signs of hereditary cancer were: 8.3% in group of young patients (under 40 years), 20.0% in patients with bilateral cancer and 5.7% in patients with family history of breast or ovarian cancers. We tested 516 BC patients residing on the territory of the Buryat-Aginsky district, Republics of Tyva and Altai. Out of them, there were 197 patients among the indigenous population (buryats, tuvinians, altaians), and 319 patients among newcomers (Slavic ethnics). Mutations BRCA1 5382insC were detected only in women from Slavic ethnic groups. The frequency of BRCA1 5382insC mutation was 6% in the group where family history was excluded and 14% in the group of patients with characteristics of family cancer. Allele BRCA1 5382insC was not found in indigenous breast cancer patients, although 59 patients had signs of hereditary cancer. In women from Slavic ethnic group, the BRCA1 185delAG, BRCA1 4153delAG and BRCA1 T300G mutations were detected in 9.1% of cases and were not found in patients among the indigenous population. Conclusion: studies of mutations in the BRCA1 gene in breast cancer patients from Siberia confirmed data on the high frequency of «founder mutation» BRCA1 5382insC in Slavic population and indicate the advisability of further studies to identify the genes responsible for the occurrence of hereditary breast cancer in the indigenous population. Обоснование: этническая разнородность населения Сибири предполагает наличие разных наследственных мутаций в генах BRCA1/2, ассоциированных с раком молочной железы (РМЖ) и раком яичников в различных популяциях, спектр которых не изучен. Цель исследования: оценить частоту встречаемости наиболее распространенных в РФ мутаций BRCA1/2 (BRCA1 5382insC, BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT) у представительниц коренного и пришлого населения Сибири. Методы: протестирован 1281 образец геномной ДНК на наличие распространенных мутаций у больных с диагнозом РМЖ. Результаты: из 765 больных РМЖ славянской принадлежности 27 человек (3,5%) были носителями аллеля BRCA1 5382insC. Частота мутации у пациенток с признаками наследственного рака составила: у молодых пациенток до 40 лет — 8,3%, у пациенток с билатеральным раком — 20,0%, при отягощенном семейном анамнезе — 5,7%. На наличие мутации BRCA15382insC протестировано 516 больных РМЖ из Агинского бурятского автономного округа, республик Тыва и Алтай, из них 319 женщин пришлого населения (славянки) и 197 представительниц коренного населения (бурятки, тувинки, алтайки). Мутации обнаружены только у славянок, частота без учета семейного анамнеза составила 6%, с учетом признаков семейного рака — около 14%. У больных РМЖ коренного населения мутация не обнаружена, хотя 59 пациенток имеют признаки наследственного рака. Мутации BRCA1 185delAG, BRCA1 4153delAG и BRCA1 T300G выявлены у славянок в 6,7% случаев и не выявлены у представительниц коренного населения. Заключение: получены данные о высокой частоте встречаемости «мутации-основателя» 5382insC у больных РМЖ славянской популяции и отсутствии «славянских» мутаций у больных РМЖ женщин монголоидного происхождения. Актуальны исследования по выявлению генов наследственного рака молочной железы у представительниц коренного населения.

Gravitomagnetic Effects in the Propagation of Electromagnetic Waves in Variable Gravitational Fields of Arbitrary-Moving and Spinning Bodies

Propagation of light in the gravitational field of self-gravitating spinning bodies moving with arbitrary velocities is discussed. The gravitational field is assumed to be "weak" everywhere. Equations of motion of a light ray are solved in the first post-Minkowskian approximation that is linear with respect to the universal gravitational constant $G$. We do not restrict ourselves with the approximation of gravitational lens so that the solution of light geodesics is applicable for arbitrary locations of source of light and observer. This formalism is applied for studying corrections to the Shapiro time delay in binary pulsars caused by the rotation of pulsar and its companion. We also derive the correction to the light deflection angle caused by rotation of gravitating bodies in the solar system (Sun, planets) or a gravitational lens. The gravitational shift of frequency due to the combined translational and rotational motions of light-ray-deflecting bodies is analyzed as well. We give a general derivation of the formula describing the relativistic rotation of the plane of polarization of electromagnetic waves (Skrotskii effect). This formula is valid for arbitrary translational and rotational motion of gravitating bodies and greatly extends the results of previous researchers. Finally, we discuss the Skrotskii effect for gravitational waves emitted by localized sources such as a binary system. The theoretical results of this paper can be applied for studying various relativistic effects in microarcsecond space astrometry and developing corresponding algorithms for data processing in space astrometric missions such as FAME, SIM, and GAIA.Comment: 36 pages, 1 figure, submitted to Phys. Rev.

Optical Light Curves of Supernovae

Photometry is the most easily acquired information about supernovae. The light curves constructed from regular imaging provide signatures not only for the energy input, the radiation escape, the local environment and the progenitor stars, but also for the intervening dust. They are the main tool for the use of supernovae as distance indicators through the determination of the luminosity. The light curve of SN 1987A still is the richest and longest observed example for a core-collapse supernova. Despite the peculiar nature of this object, as explosion of a blue supergiant, it displayed all the characteristics of Type II supernovae. The light curves of Type Ib/c supernovae are more homogeneous, but still display the signatures of explosions in massive stars, among them early interaction with their circumstellar material. Wrinkles in the near-uniform appearance of thermonuclear (Type Ia) supernovae have emerged during the past decade. Subtle differences have been observed especially at near-infrared wavelengths. Interestingly, the light curve shapes appear to correlate with a variety of other characteristics of these supernovae. The construction of bolometric light curves provides the most direct link to theoretical predictions and can yield sorely needed constraints for the models. First steps in this direction have been already made.Comment: To be published in:"Supernovae and Gamma Ray Bursters", Lecture Notes in Physics (http://link.springer.de/series/lnpp

The Baikal Deep Underwater Neutrino Experiment: Results, Status, Future

We review the present status of the Baikal Underwater Neutrino Experiment and present results obtained with the various stages of the stepwise increasing detector: NT-36 (1993-95), NT-72 (1995-96) and NT-96 (1996-97). Results cover atmospheric muons, first clear neutrino events, search for neutrinos from WIMP annihilation in the center of the Earth, search for magnetic monopoles, and -- far from astroparticle physics -- limnology.Comment: Talk given at the Int. School on Nuclear Physics, Erice, Sept.199