Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter ...1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 R Jupiter in a 3.9 day orbit.
The line-of-sight velocities and O III 5007 AA expansion velocities are measured for 11 planetary nebulae (PNs) in the Virgo Cluster core, at 15 Mpc distance, with the FLAMES spectrograph on the ESO ...VLT. These PNs are located about halfway between the two giant elliptical galaxies M87 and M86. From the O III 5007 AA line profile widths, the average half-width at half-maximum expansion velocity for this sample of 11 PNs is unk = 16.5 km s super(-1) (rms = 2.6 km s super(-1)). We use the PN subsample bound to M87 to remove the distance uncertainties and the resulting O III 5007 AA luminosities to derive the central star masses. We find these masses to be at least 0.6 M unk and obtain PN observable lifetimes t sub(PN) < 2000 yr, which imply that the bright PNs detected in the Virgo Cluster core are compact, high-density nebulae. We finally discuss several scenarios for explaining the high central star masses in these bright M87 halo PNs.
We search for evidence of diffuse Ly alpha emission from extended neutral hydrogen surrounding Ly alpha emitting galaxies (LAEs) using deep narrow-band images of the Extended Chandra Deep Field ...South. By stacking the profiles of 187 LAEs at z = 2.06, 241 LAEs at z = 3.10, and 179 LAEs at z = 3.12, and carefully performing low-surface brightness photometry, we obtain mean surface brightness maps that reach 9.9, 8.7, and 6.2 x 10(-19) erg cm(-2) s(-1) arcsec(-2) in the emission line. We undertake a thorough investigation of systematic uncertainties in our surface brightness measurements and find that our limits are 5-10 times larger than would be expected from Poisson background fluctuations; these uncertainties are often underestimated in the literature. At z similar to 3.1, we find evidence for extended halos with small-scale lengths of 5-8 kpc in some but not all of our sub-samples. We demonstrate that sub-samples of LAEs with low equivalent widths and brighter continuum magnitudes are more likely to possess such halos. At z similar to 2.1, we find no evidence of extended Ly alpha emission down to our detection limits. Through Monte-Carlo simulations, we also show that we would have detected large diffuse LAE halos if they were present in our data sets. We compare these findings to other measurements in the literature and discuss possible instrumental and astrophysical reasons for the discrepancies.
The standard clinical approach of dose measurement using a Farmer type fixed plane parallel cylindrical ionization chamber produces erroneous results in the build-up region. We studied dose ...distribution in this region using a Monte Carlo simulation technique and compared our results with data measured using extrapolation, parallel plate, and cylindrical farmer type ionization chambers for 6 and 10
MV photon beams from two different accelerators. The extrapolation chamber data agreed favorably with the Monte Carlo results, suggesting that dose at the skin surface and a few mm beneath is significantly lower than conventionally accepted values.
Purpose: Persisting symptomatology after breast-conserving surgery and radiation is frequently reported. In most cases, symptoms in the breast resolve without further treatment. In some instances, ...however, pain, erythema, and edema can persist for years and can impact the patient’s quality of life. Hyperbaric oxygen therapy was shown to be effective as treatment for late radiation sequelae. The objective of this study was to assess the efficacy of hyperbaric oxygen therapy in symptomatic patients after breast cancer treatment.
Patients and Methods: Forty-four patients with persisting symptomatology after breast-conservation therapy were prospectively observed. Thirty-two women received hyperbaric oxygen therapy in a multiplace chamber for a median of 25 sessions (range, 7–60). One hundred percent oxygen was delivered at 240 kPa for 90-min sessions, 5 times per week. Twelve control patients received no further treatment. Changes throughout the irradiated breast tissue were scored prior to and after hyperbaric oxygen therapy using modified LENT-SOMA criteria.
Results: Hyperbaric oxygen therapy patients showed a significant reduction of pain, edema, and erythema scores as compared to untreated controls (
p < 0.001). Fibrosis and telangiectasia, however, were not significantly affected by hyperbaric oxygen therapy. Seven of 32 women were free of symptoms after hyperbaric oxygen therapy, whereas all 12 patients in the control group had persisting complaints.
Conclusions: Hyperbaric oxygen therapy should be considered as a treatment option for patients with persisting symptomatology following breast-conserving therapy.
The commercially available brachytherapy treatment-planning systems today, usually neglects the attenuation effect from stainless steel (SS) tube when Fletcher-Suit-Delclos (FSD) is used in treatment ...of cervical and endometrial cancers. This could lead to potential inaccuracies in computing dwell times and dose distribution. A more accurate analysis quantifying the level of attenuation for high-dose-rate (HDR) iridium 192 radionuclide ((192)Ir) source is presented through Monte Carlo simulation verified by measurement.
In this investigation a general Monte Carlo N-Particles (MCNP) transport code was used to construct a typical geometry of FSD through simulation and compare the doses delivered to point A in Manchester System with and without the SS tubing. A quantitative assessment of inaccuracies in delivered dose vs. the computed dose is presented. In addition, this investigation expanded to examine the attenuation-corrected radial and anisotropy dose functions in a form parallel to the updated AAPM Task Group No. 43 Report (AAPM TG-43) formalism. This will delineate quantitatively the inaccuracies in dose distributions in three-dimensional space. The changes in dose deposition and distribution caused by increased attenuation coefficient resulted from presence of SS are quantified using MCNP Monte Carlo simulations in coupled photon/electron transport. The source geometry was that of the Vari Source wire model VS2000. The FSD was that of the Varian medical system. In this model, the bending angles of tandem and colpostats are 15 degrees and 120 degrees , respectively. We assigned 10 dwell positions to the tandem and 4 dwell positions to right and left colpostats or ovoids to represent a typical treatment case. Typical dose delivered to point A was determined according to Manchester dosimetry system.
Based on our computations, the reduction of dose to point A was shown to be at least 3%. So this effect presented by SS-FSD systems on patient dose is of concern.
We report on the discovery of a faint (M sub(V)6 -10.6 c 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily ...resolved in our images, as our color magnitude diagram (CMD) extends 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of M/H = -2.3 c 0.3 and show that the metallicity dispersion is less than 0.6 dex at 95% confidence. We also use the galaxy's lack of AGB stars and the absence of objects brighter than M sub(bol) 6 -4.1 c 0.2 to show that the system is old (t 10 Gyr). Finally, we derive the object's structural parameters and show that the galaxy displays no obvious evidence of tidal threshing. Since the tip of the red giant branch distance (m - M) sub(0) = 31.23 c 0.17 or D = 17.6 c 1.4 Mpc puts the galaxy near the core of the Virgo cluster, one might expect the object to have undergone some tidal processing. Yet the chemical and morphological similarity between the dwarf and the dSph galaxies of the Local and M81 Group demonstrates that the object is indeed pristine and not the shredded remains of a much larger galaxy. We discuss the possible origins of this galaxy and suggest that it is just now falling into Virgo for the first time.
Objective. To compare the survival, morbidity, and cost of treating women with intermediate risk endometrial cancer with postoperative vaginal cuff brachytherapy versus observation followed by ...treatment for vaginal recurrence.
Methods. A cost-effectiveness analysis was performed comparing two treatment strategies for intermediate risk endometrial cancer (Stage IC, IG3, II—tumors limited to the uterus with greater than 50% myometrial invasion or poor differentiation or cervical metastasis). All patients undergo hysterectomy, oophorectomy, and lymphadenectomy: strategy 1—postoperative vaginal cuff brachytherapy, strategy 2—observation. Strategy 2 patients who develop vaginal recurrence undergo diagnostic work-up followed by teletherapy and brachytherapy. All six principles of cost-effectiveness analysis were employed. Importantly, actual payer costs were evaluated, not charges.
Results. Although the treatment for vaginal cuff recurrence is expensive, since only 8% of patients develop a vaginal recurrence, there was a 31% decreased cost by not treating patients with postoperative low-dose rate brachytherapy (strategy 2). Also, although the complication rate for teletherapy is greater than brachytherapy, since only 8% of patients develop a vaginal recurrence and require teletherapy, projected complication rates for the two strategies are similar. Survival would be decreased 3% by withholding postoperative brachytherapy (strategy 2). With postoperative high-dose rate brachytherapy (strategy 1), the cost per life saved would be $38
764.
Conclusion. Using a cost-effectiveness analysis, we have shown that withholding postoperative brachytherapy for patients with intermediate risk endometrial cancer results in a 31% decrease in cost, has a similar radiation complication rate, and results in a 3% decrease in survival.
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