New Young Star Candidates in BRC 27 and BRC 34

We used archival Spitzer Space Telescope mid-infrared data to search for young stellar objects (YSOs) in the immediate vicinity of two bright-rimmed clouds, BRC 27 (part of CMa R1) and BRC 34 (part of the IC 1396 complex). These regions both appear to be actively forming young stars, perhaps triggered by the proximate OB stars. In BRC 27, we find clear infrared excesses around 22 of the 26 YSOs or YSO candidates identified in the literature, and identify 16 new YSO candidates that appear to have IR excesses. In BRC 34, the one literature-identified YSO has an IR excess, and we suggest 13 new YSO candidates in this region, including a new Class I object. Considering the entire ensemble, both BRCs are likely of comparable ages, within the uncertainties of small number statistics and without spectroscopy to confirm or refute the YSO candidates. Similarly, no clear conclusions can yet be drawn about any possible age gradients that may be present across the BRCs.Comment: 54 pages, 19 figures, accepted by A

The Effect of Oestrone on the Incidence of Mammary Carcinoma and Adenoma in C3Hf Breeders After Late Ovariectomy

THE effects on the incidence of spontaneous mammary carcinoma of breeding and of age in C3Hf mice have been recorded (Pullinger and Iversen, 1960). None of the tests done to detect the mammary tumour agent disclosed its presence in this strain (Pullinger, 1960a). A reduction in mammary tumour incidence in former breeding females after ovariectomy alone was reported (Pullinger, 1960b). In the present paper the incidence of mammary carcinoma and adenoma in C3Hf breeders after late ovariectomy with subsequent treatment with oestrone is described. MATERIALS AND METHODS Surplus breeders of generations F5 to F16 of the pure line C3Hf colony were ovariectomised at the age of 9 to 11 months. The operation and subsequent management were the same as that recorded for ovariectomy alone (Pullinger, 1960b) except that the animals were treated thereafter with oestrone once weekly for 30 weeks. One experimental group comprising 30 animals received 5,tg. weekly, the other of 23 received 10,ug. weekly. The oestrone was dissolved i