51 research outputs found
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Evaluation of effectiveness of the PlasmaJet surgical device in the treatment of advanced stage ovarian cancer (PlaComOv-study): study protocol of a randomized controlled trial in the Netherlands
Background: The most important goal for survival benefit of advanced stage ovarian cancer is to surgically remove
all visible tumour, because complete cytoreductive surgery (CCS) has been shown to be associated with prolonged
survival.
In a remarkable number of women, CCS is very challenging. Especially in women with many small metastases on
the peritoneum and intestinal surface, conventional CCS with electrosurgery is not able to be “complete” in
removing safely all visible tumour.
In this randomized controlled trail (RCT) we investigate whether the use of the PlasmaJet Surgical Device increases
the rate of CCS, and whether this indeed leads to a longer progression free and overall survival.
The main research question is: does the use of the PlasmaJet Surgical Device in surgery for advanced stage ovarian
cancer result in an increased number of complete cytoreductive surgeries when compared with conventional
surgical techniques. Secondary study objectives are: 30-day morbidity, duration of surgery, blood loss, length of
hospitalisation, Quality of Life, disease-free survival, overall survival, percentage colostomy, cost-effectiveness.
Methods: The study design is a multicentre single-blinded superiority RCT in two university and nine non-university
hospitals in The Netherlands. Three hundred and thirty women undergoing cytoreductive surgery for advanced
stage ovarian carcinoma (FIGO Stage IIIB-IV) will be randomized into two arms: use of the PlasmaJet (intervention
group) versus the use of standard surgical instruments combined with electrocoagulation (control group). The
primary outcome is the rate of complete cytoreductive surgery in both groups.
Secondary study objectives are: 30-day morbidity, duration of surgery, blood loss, length of hospitalisation, Quality of
Life, disease-free survival, overall survival, percentage colostomy, cost-effectiveness. Quality of life will be evaluated
using validated questionnaires at baseline, at 1 and 6 months after surgery and at 1, 2, 3 and 4 years after surgery
Discussion: We hypothesize the additional value of the use of the PlasmaJet in CCS for advanced stage epithelial
ovarian cancer. More knowledge about efficacy, side effects, recurrence rates, cost effectiveness and pathology findings
after using the PlasmaJet Device is advocated. This RCT may aid in this void
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