The Eclipsing Binary BG Geminorum: Improved Constraints on the Orbit and the Structure of the Accretion Disk

We describe new optical photometric and spectroscopic observations of the semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg I absorption at secondary maximum indicates the presence of cool material in the outer edge of the disk surrounding the unseen primary star. Detection of weak He I emission implies a hot radiation source at the inner edge of the disk. If the velocity variations in the Hbeta emission line track the orbital motion of the primary star, the primary star has an orbital semiamplitude of K1 = K(Hbeta) = 16.0 +- 4.6 km/sec. This result yields a mass ratio, q = 0.22 +- 0.07, consistent with the q = 0.1 derived from the large ellipsoidal variation. Despite this progress, the nature of the primary star - B-type star or black hole - remains uncertain.Comment: 9 pages of text, 3 tables, and 4 figures; to appear in AJ, August 200

A Study of Pi Aquarii During a Quasi-normal Star Phase: Refined Fundamental Parameters and Evidence for Binarity

We present the results of recent multicolor photometric and high-resolution spectroscopic observations of the bright Be star Pi Aquarii. Observational data collected from the literature were used to study the star's variations over the last four decades. The star is identified with the IR sources F22227+0107 in the IRAS Faint Point Source catalog and MSX5_G066.0066-44.7392 in the MSX catalog. The variations in near-IR brightness of Pi Aqr are found to be among the largest reported for Be stars. Since 1996, the star has shown only weak signs of circumstellar emission, which has allowed us to refine the fundamental stellar parameters: A_V=0.15 mag., T_eff=24000K, log g=3.9, and M_V=-2.95 mag. A weak emission component of the H-alpha line has been detected during the recent quasi-normal star phase. From analysis of the H-alpha line profiles, we find anti-phased radial velocity variations of the emission component and the photospheric absorption, with a period of 84.1 days and semi-amplitudes of 101.4 and 16.7 km/s, respectively. This result suggests that Pi Aqr may be a binary system consisting of stars with masses of M_1 sin^{3}i = 12.4 M_sun, M_2 sin^{3}i = 2.0 M_sun. We also estimate the orbital inclination angle to be between 50 and 75 degrees. We suggest that the photometric, spectroscopic, and polarimetric variations observed during the second half of the 20th century may be due to variable mass transfer between the binary components.Comment: 26 pages (including 8 figs, 2 tables), accepted by Ap

Vitamin A derivatives in the prevention and treatment of human cancer.

Vitamin A is essential for normal cellular growth and differentiation. A vast amount of laboratory data have clearly demonstrated the potent antiproliferative and differentiation-inducing effects of vitamin A and the synthetic analogues (retinoids). Recent in-vitro work has led to the exciting proposal that protein kinase-C may be centrally involved in many of retinoids' anticancer actions including the effects on ornithine decarboxylase induction, intracellular polyamine levels, and epidermal growth factor receptor number. Several intervention trials have clearly indicated that natural vitamin A at clinically tolerable doses has only limited activity against human neoplastic processes. Therefore, clinical work has focused on the synthetic derivatives with higher therapeutic indexes. In human cancer prevention, retinoids have been most effective for skin diseases, including actinic keratosis, keratoacanthoma, epidermodysplasia verruciformis, dysplastic nevus syndrome, and basal cell carcinoma. Several noncutaneous premaligancies, however, are currently receiving more attention in retinoid trials. Definite retinoid activity has been documented in oral leukoplakia, laryngeal papillomatosis, superficial bladder carcinoma, cervical dysplasia, bronchial metaplasia, and preleukemia. Significant therapeutic advances are also occurring with this class of drugs in some drug-resistant malignancies and several others that have become refractory, including advanced basal cell cancer, mycosis fungoides, melanoma, acute promyelocytic leukemia, and squamous cell carcinoma of the skin and of the head and neck. This report comprehensively presents the clinical data using retinoids as anticancer agents in human premalignant disorders and outlines the ongoing and planned studies with retinoids in combination and adjuvant therapy

Qualidade do leite: utopia sem um programa sério de monitoramento da ocorrência de mastite bovina

Bovine mastitis is still a costly issue in dairy farms, besides public health aspects considering the pathogen transmission to humans. Its multiple etiology with a high number of pathogens involved, demands a rigorous control program for monitoring and milk quality control, based on diagnostic actions and epidemiological vigilance regarding parameters which indirectly are associated with the occurrence of mastitis in dairy herds, as the California Mastitis Test (CMT) and Somatic Cell Count (SCC/mL of milk), of individual milk samples obtained from each cow, and from bulk tank which also allows the Total Bacteria Count (TBC), usually related to the incidence of mastitis, especially in subclinical cases. It is important to reinforce the microbiological milk exam, also to stress the importance of the milking process as a critical point, and to determine risk factors for mastitis. Based on these aspects, this review is presented with the aim to obtain high quality milk products, compromising the personal enrolled in milk production to be conscious that milk quality depends on all, inclusive the consumers which are the final element in the milk production chain.Departamento de Higiene Veterinária e Saúde Pública Universidade Estadual Paulista Júlio de Mesquita Filho (Unesp), Distrito de Rubião Junior s/n, Botucatu, SP 18618-970Departamento de Higiene Veterinária e Saúde Pública Universidade Estadual Paulista Júlio de Mesquita Filho (Unesp), Distrito de Rubião Junior s/n, Botucatu, SP 18618-97