COMPASS: a 2.6m telescope for CMBR polarization studies

COMPASS (COsmic Microwave Polarization at Small Scale) is an experiment devoted to measuring the polarization of the CMBR. Its design and characteristics are presented

A Limit on the Large Angular Scale Polarization of the Cosmic Microwave Background

We present an upper limit on the polarization of the Cosmic Microwave Background at 7 degree angular scales in the frequency band between 26 and 36 GHz, produced by the POLAR experiment. The campaign produced a map of linear polarization over the R.A. range 112 degrees - 275 degrees at declination 43degrees. The model-independent upper limit on the E-mode polarization component of the CMB at angular scales l = 2 - 20 is 10 microKelvin (95% confidence). The corresponding limit for the B-mode is also 10 microKelvin. Constraining the B-mode power to be zero, the 95% confidence limit on E-mode power alone is 8 microKelvin

COMPASS: a 2.6m telescope for CMBR polarization studies

Abstract. COMPASS (COsmic Microwave Polarization at Small Scale) is an experiment devoted to measuring the polarization of the CMBR. Its design and characteristics are presented

COMPASS: a 2.6m telescope for CMBR polarization studies

Abstract. COMPASS (COsmic Microwave Polarization at Small Scale) is an experiment devoted to measuring the polarization of the CMBR. Its design and characteristics are presented

SU-D-202-03: Statistical Segmentation On Quantitative CT for Assessing Spatial Tumor Response During Radiation Therapy Delivery

Purpose: Develop a method to segment regions of interest (ROIs) in tumor with statistically similar Hounsfield unit (HU) values and/or HU changes during chemoradiation therapy (CRT) delivery, to assess spatial tumor treatment response based on daily CTs during CRT delivery. Methods: Generate a three region map of ROIs with differential HUs, by sampling neighboring voxels around a selected voxel and comparing to the mean of the entire ROI using a t-test. The cumulative distribution function, P, is calculated from the t-test. The P value is assigned to be the value at the selected voxel, and this is repeated over all voxels in the initial ROI. Three regions are defined as: (1-P) \u3c 0.00001 (mid region), and 0.00001 \u3c (1-P) (mean greater than baseline and mean lower than baseline). The test is then expanded to compare daily CT sets acquired during routine CT-guided RT delivery using a CT-on-rails. The first fraction CT is used as the baseline for comparison. We tested 15 pancreatic head tumor cases undergoing CRT, to identify the ROIs and changes corresponding to normal, fibrotic, and tumor tissue. The obtained ROIs were compared with MRI-ADC maps acquired pre- and post-CRT. Results: The ROIs in 13 out of 15 patients’ first fraction CTs and pre-CRT MRIs matched the general region and slices covered, as well as in 6 out of the 9 patients with post-CRT MRIs. The high HU region designated by the t-test was seen to correlate with the tumor region in MR, and these ROIs are positioned within the same region over the course of treatment. In patients with poorly delineated tumors in MR, the t-test was inconclusive. Conclusion: The proposed statistical segmentation technique shows the potential to identify regions in tumor with differential HUs and HU changes during CRT delivery for patients with pancreas head cancer

COMPASS: An upper limit on Cosmic Microwave background Polaritazion at an Angular Scale of 20’

COMPASS is an on-axis 2.6 m telescope coupled to a correlation polarimeter operating at a wavelength of 1 cm. The entire instrument was built specifically for cosmic microwave background (CMB) polarization studies. We report here on observations of 2001 February–April using this system. We set an upper limit on E-mode polarized anisotropies of 1036 K2 (95% confidence limit) in the l range 93–555

Can Reform Models of Value Added Taxation Stop the VAT Evasion and Revenue Shortfalls in the EU?

VAT evasion caused by the growth of carousel fraud has recently led to significant VAT revenue losses in the EU. Carousel fraud works such that intra-EU firms repeatedly carry out cross-border supply and purchase of goods and services, leading to the fraudulent retention of revenue. This study discusses three reform models of the VAT system in Germany, whose implementation would open up further possibilities for tax evasion and lead to a considerable increase in administrative costs.VAT evasion, reform models, carousel fraud, Germany, EU,