5 research outputs found
Stellar parameters of Be stars observed with X-shooter
Aims. The X-shooter archive of several thousand telluric star spectra was
skimmed for Be and Be-shell stars to derive the stellar fundamental parameters
and statistical properties, in particular for the less investigated late type
Be stars, and the extension of the Be phenomenon into early A stars. Methods.
An adapted version of the BCD method is used, utilizing the Balmer
discontinuity parameters to determine effective temperature and surface
gravity. This method is optimally suited for late B stars. The projected
rotational velocity was obtained by profile fitting to the Mg ii lines of the
targets, and the spectra were inspected visually for the presence of peculiar
features such as the infrared Ca ii triplet or the presence of a double Balmer
discontinuity. The Balmer line equivalent widths were measured, but due to
uncertainties in determining the photospheric contribution are useful only in a
subsample of Be stars for determining the pure emission contribution. Results.
A total of 78 Be stars, mostly late type ones, were identified in the X-shooter
telluric standard star archive, out of which 48 had not been reported before.
The general trend of late type Be stars having more tenuous disks and being
less variable than early type ones is confirmed. The relatively large number
(48) of relatively bright (V > 8.5) additional Be stars casts some doubt on the
statistics of late type Be stars; they are more common than currently thought:
The Be/B star fraction may not strongly depend on spectral subtype.Comment: Accepted for publication in A&
Age at diagnosis in women with non-metastatic breast cancer: Is it related to prognosis?
Objective: Primary objective was to verify whether breast cancer patients aged less than 40Â years at diagnosis have poorer prognosis than older patients. Secondary to assess prognostic factors influencing disease free survival.
Methods: 941 women were diagnosed with non-metastatic breast cancer at NCI, Cairo in 2003. Epidemiologic, clinico-pathological characteristics, treatment modalities and disease free survival were compared among the two age groups. Prognostic factors were evaluated for association with disease-free survival.
Results: One hundred-eighty-one patients (19.2%) were younger than 40 years and 760 (80.8%) were older. Older women presented with higher rates of comorbidities and younger women presented with more hormone non-responsive tumors. Young women presented with larger tumors pT4 = 13.8% compared to 8.6% in older women, yet not significant. Young women were treated with more conservative surgery, more adjuvant chemotherapy and radiotherapy while older women with more radical mastectomies and more hormonal treatment. Recurrence rates were significantly higher among young women 44.2% compared to 34.5% in older women. Five year disease free survival in young women was 38.9% ± 4.6% compared to 48.6% ± 2.5% with adjusted hazard ratio of 1.22 95% CI (0.91–1.64), p = 0.19. Multivariate analyses identified positive axillary lymph nodes (pN2-pN3), larger tumor size (pT3-pT4), hypertension, lobular carcinoma type and lack of adjuvant systemic treatment as independent factors associated with poor DFS.
Conclusion: Young women were not found to have poorer prognosis, yet they presented with more ER negative tumors. Most of women presented with advanced stage and young women had higher recurrence rates