344 research outputs found

    RCS2 J232727.6-020437: An Efficient Cosmic Telescope at z=0.6986z=0.6986

    Full text link
    We present a detailed gravitational lens model of the galaxy cluster RCS2 J232727.6-020437. Due to cosmological dimming of cluster members and ICL, its high redshift (z=0.6986z=0.6986) makes it ideal for studying background galaxies. Using new ACS and WFC3/IR HST data, we identify 16 multiple images. From MOSFIRE follow up, we identify a strong emission line in the spectrum of one multiple image, likely confirming the redshift of that system to z=2.083z=2.083. With a highly magnified (μ2\mu\gtrsim2) source plane area of 0.7\sim0.7 arcmin2^2 at z=7z=7, RCS2 J232727.6-020437 has a lensing efficiency comparable to the Hubble Frontier Fields clusters. We discover four highly magnified z7z\sim7 candidate Lyman-break galaxies behind the cluster, one of which may be multiply-imaged. Correcting for magnification, we find that all four galaxies are fainter than 0.5L0.5 L_{\star}. One candidate is detected at >10σ{>10\sigma} in both Spitzer/IRAC [3.6] and [4.5] channels. A spectroscopic follow-up with MOSFIRE does not result in the detection of the Lyman-alpha emission line from any of the four candidates. From the MOSFIRE spectra we place median upper limits on the Lyman-alpha flux of 514×1019ergs1cm25-14 \times 10^{-19}\, \mathrm{erg \,\, s^{-1} cm^{-2}} (5σ5\sigma).Comment: 14 pages, 9 figures, submitted to ApJ on 3/06/201

    Spitzer UltRa Faint SUrvey Program (SURFS UP). II. IRAC-Detected Lyman-Break Galaxies at 6 < z < 10 Behind Strong-Lensing Clusters

    Get PDF
    We study the stellar population properties of the IRAC-detected 6z106 \lesssim z \lesssim 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program (SURFS UP). Using the Lyman Break selection technique, we find a total of 16 new galaxy candidates at 6z106 \lesssim z \lesssim 10 with S/N3S/N \geq 3 in at least one of the IRAC 3.6μ3.6\mum and 4.5μ4.5\mum bands. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of 1.2\sim 1.2--5.55.5. We find that the IRAC-detected 6z106 \lesssim z \lesssim 10 sample is likely not a homogeneous galaxy population: some are relatively massive (stellar mass as high as 4×109M4 \times 10^9\,M_{\odot}) and evolved (age 500\lesssim 500 Myr) galaxies, while others are less massive (Mstellar108MM_{\text{stellar}}\sim 10^8\,M_{\odot}) and very young (10\sim 10 Myr) galaxies with strong nebular emission lines that boost their rest-frame optical fluxes. We identify two Lyα\alpha emitters in our sample from the Keck DEIMOS spectra, one at zLyα=6.76z_{\text{Ly}\alpha}=6.76 (in RXJ1347) and one at zLyα=6.32z_{\text{Ly}\alpha}=6.32 (in MACS0454). We show that IRAC [3.6][4.5][3.6]-[4.5] color, when combined with photometric redshift, can be used to identify galaxies likely with strong nebular emission lines within certain redshift windows.Comment: ApJ in pres

    Subcutaneous rupture of the Achilles tendon and ipsilateral fracture of the medial malleolus

    Get PDF
    BACKGROUND: Although ankle fractures and an Achilles tendon rupture are relatively frequent in isolation, their association in the same injury is uncommon. CASE PRESENTATION: A 38 year old male tree surgeon fell six meters from a tree, sustaining a subcutaneous rupture of the Achilles tendon and an ipsilateral closed fracture of the medial malleolus. The injuries were diagnosed following clinical examination and imaging. CONCLUSION: This injury combination is infrequent, and management of the Achilles tendon rupture should take into account the necessity not to secondarily displace the fracture of the medial malleollus

    Radon and childhood cancer

    Get PDF
    British Journal of Cancer (2002) 87, 1336–1337. doi:10.1038/sj.bjc.6600671 www.bjcancer.co

    Breakdown of the adiabatic limit in low dimensional gapless systems

    Get PDF
    It is generally believed that a generic system can be reversibly transformed from one state into another by sufficiently slow change of parameters. A standard argument favoring this assertion is based on a possibility to expand the energy or the entropy of the system into the Taylor series in the ramp speed. Here we show that this argumentation is only valid in high enough dimensions and can break down in low-dimensional gapless systems. We identify three generic regimes of a system response to a slow ramp: (A) mean-field, (B) non-analytic, and (C) non-adiabatic. In the last regime the limits of the ramp speed going to zero and the system size going to infinity do not commute and the adiabatic process does not exist in the thermodynamic limit. We support our results by numerical simulations. Our findings can be relevant to condensed-matter, atomic physics, quantum computing, quantum optics, cosmology and others.Comment: 11 pages, 5 figures, to appear in Nature Physics (originally submitted version

    Hybrid video quality prediction: reviewing video quality measurement for widening application scope

    Get PDF
    A tremendous number of objective video quality measurement algorithms have been developed during the last two decades. Most of them either measure a very limited aspect of the perceived video quality or they measure broad ranges of quality with limited prediction accuracy. This paper lists several perceptual artifacts that may be computationally measured in an isolated algorithm and some of the modeling approaches that have been proposed to predict the resulting quality from those algorithms. These algorithms usually have a very limited application scope but have been verified carefully. The paper continues with a review of some standardized and well-known video quality measurement algorithms that are meant for a wide range of applications, thus have a larger scope. Their individual artifacts prediction accuracy is usually lower but some of them were validated to perform sufficiently well for standardization. Several difficulties and shortcomings in developing a general purpose model with high prediction performance are identified such as a common objective quality scale or the behavior of individual indicators when confronted with stimuli that are out of their prediction scope. The paper concludes with a systematic framework approach to tackle the development of a hybrid video quality measurement in a joint research collaboration.Polish National Centre for Research and Development (NCRD) SP/I/1/77065/10, Swedish Governmental Agency for Innovation Systems (Vinnova

    Detection of Polarization in the Cosmic Microwave Background using DASI

    Get PDF
    We report the detection of polarized anisotropy in the Cosmic Microwave Background radiation with the Degree Angular Scale Interferometer (DASI), located at the Amundsen-Scott South Pole research station. Observations in all four Stokes parameters were obtained within two 3.4 FWHM fields separated by one hour in Right Ascension. The fields were selected from the subset of fields observed with DASI in 2000 in which no point sources were detected and are located in regions of low Galactic synchrotron and dust emission. The temperature angular power spectrum is consistent with previous measurements and its measured frequency spectral index is -0.01 (-0.16 -- 0.14 at 68% confidence), where 0 corresponds to a 2.73 K Planck spectrum. The power spectrum of the detected polarization is consistent with theoretical predictions based on the interpretation of CMB anisotropy as arising from primordial scalar adiabatic fluctuations. Specifically, E-mode polarization is detected at high confidence (4.9 sigma). Assuming a shape for the power spectrum consistent with previous temperature measurements, the level found for the E-mode polarization is 0.80 (0.56 -- 1.10), where the predicted level given previous temperature data is 0.9 -- 1.1. At 95% confidence, an upper limit of 0.59 is set to the level of B-mode polarization with the same shape and normalization as the E-mode spectrum. The TE correlation of the temperature and E-mode polarization is detected at 95% confidence, and also found to be consistent with predictions. These results provide strong validation of the underlying theoretical framework for the origin of CMB anisotropy and lend confidence to the values of the cosmological parameters that have been derived from CMB measurements.Comment: 20 pages, 6 figure

    Thyroid nodularity after childhood irradiation for lymphoid hyperplasia: a comparison of questionnaire and clinical findings

    Full text link
    Ionizing radiation is a well-established cause of thyroid cancer and modularity, however, important questions relating to the magnitude of the risk following low-dose medical exposures remain unresolved. To address these issues, we conducted a follow-up study of 1590 individuals treated between 1938 and 1969 with X-rays for childhood lymphoid hyperplasia (av. thyroid DOSE = 24 cGy) and 1499 individuals treated with surgery only. Thyroid nodularity was determined from self-administered questionnaires completed by 1195 irradiated and 1063 surgically-treated subjects and from clinical examinations of 602 irradiated and 457 non-irradiated subjects. A much higher relative risk (RR) for radiation-induced thyroid nodules was estimated from the questionnaire than from the clinical examination data, 15.8 and 2.7, respectively. (The corresponding estimates of excess RR per cGy were 64 and 7%). Analysis of the examination data revealed a strong dose-response relationship, similar excess RR/cGy for males and females, and an inverse relationship with age at exposure. Although the thyroid gland is one of the most sensitive organs to the neoplastic effects of radiation, the radiation-induced risk of thyroid nodularity reported from questionnaire studies may over-estimate the true risk.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28887/1/0000723.pd

    CMB Telescopes and Optical Systems

    Full text link
    The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB observations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1: Telescopes and Instrumentatio

    Prognostic significance of anti-p53 and anti-KRas circulating antibodies in esophageal cancer patients treated with chemoradiotherapy

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>P53 mutations are an adverse prognostic factor in esophageal cancer. P53 and KRas mutations are involved in chemo-radioresistance. Circulating anti-p53 or anti-KRas antibodies are associated with gene mutations. We studied whether anti-p53 or anti-KRas auto-antibodies were prognostic factors for response to chemoradiotherapy (CRT) or survival in esophageal carcinoma.</p> <p>Methods</p> <p>Serum p53 and KRas antibodies (abs) were measured using an ELISA method in 97 consecutive patients treated at Saint Louis University Hospital between 1999 and 2002 with CRT for esophageal carcinoma (squamous cell carcinoma (SCCE) 57 patients, adenocarcinoma (ACE) 27 patients). Patient and tumor characteristics, response to treatment and the follow-up status of 84 patients were retrospectively collected. The association between antibodies and patient characteristics was studied. Univariate and multivariate survival analyses were conducted.</p> <p>Results</p> <p>Twenty-four patients (28%) had anti-p53 abs. Abs were found predominantly in SCCE (p = 0.003). Anti-p53 abs were associated with a shorter overall survival in the univariate analysis (HR 1.8 [1.03-2.9], p = 0.04). In the multivariate analysis, independent prognostic factors for overall and progression-free survival were an objective response to CRT, the CRT strategy (alone or combined with surgery [preoperative]) and anti-p53 abs. None of the long-term survivors had p53 abs. KRas abs were found in 19 patients (23%, no difference according to the histological type). There was no significant association between anti-KRas abs and survival neither in the univariate nor in the multivariate analysis. Neither anti-p53 nor anti-KRas abs were associated with response to CRT.</p> <p>Conclusions</p> <p>Anti-p53 abs are an independent prognostic factor for esophageal cancer patients treated with CRT. Individualized therapeutic approaches should be evaluated in this population.</p
    corecore