Shape-Based Models for Interactive Segmentation of Medical Images

Accurate image segmentation is one of the key problems in computer vision. In domains such as radiation treatment planning, dosimetrists must manually trace the outlines of a few critical structures on large numbers of images. Considerable similarity can be seen in the shape of these regions, both between adjacent slices in a particular patient and across the spectrum of patients. Consequently we should be able to model this similarity and use it to assist in the process of segmentation. Previous work has demonstrated that a constraint-based 2D radial model can capture generic shape information for certain shape classes, and can reduce user interaction by a factor of three over purely manual segmentation. Additional simulation studies have shown that a probabilistic version of the model has the potential to further reduce user interaction. This paper describes an implementation of both models in a general-purpose imaging and graphics framework and compares the usefulness of the models on several shape classes

Construing Clinton and Trump: The Effects of Psychological Distance and Voter Preference

People live in the here and now, although they can think about distal events, places and times. Thinking about distal time, places and people are referred to as psychological distance. Psychological distance is correlated with the level of construal. The level of construal refers to the level of abstractness and concreteness of the mental representation of an idea (e.g., goals, events, places, people, etc). The information that we have stored about the world can also vary on a dimension of concreteness and abstraction. The purpose of this study was to test whether psychological distance mediates the extent that we evaluate the information about the world as being more or less detailed. In the study, people performed a task that has been shown to instill different levels of psychological distance (Liberman & Trope, 1998). In the close condition, participates wrote about what they would do tomorrow. In the far condition, participants wrote about what they would do next year. In a control group, the participants described their favorite hobby. Then all groups rated Hillary Clinton and Donald Trump’s policy plans and long-term visions of America on measures of construal. People ranked the candidate they were voting for as having lower construal. Not supported was the prediction that psychological distance would affect the ratings of the candidates’ visions for the future.  B.S. (Bachelor of Science

Hot pixel contamination in the CMB correlation function?

Recently, it was suggested that the map-making procedure, which is applied to the time-ordered CMB data by the WMAP team, might be flawed by hot pixels. This could lead to a bias in the pixels having an angular distance of about 141 degrees from hot pixels due to the differential measuring process of the satellite WMAP. Here, the bias is confirmed, and the temperature two-point correlation function C(theta) is reevaluated by excluding the affected pixels. It is shown that the most significant effect occurs in C(theta) at the largest angles near theta = 180 degrees. Furthermore, the corrected correlation function C(theta) is applied to the cubic topology of the Universe, and it is found that such a multi-connected universe matches the temperature correlation better than the LCDM concordance model, provided the cubic length scale is close to L=4 measured in units of the Hubble length

Can one reconstruct masked CMB sky?

The CMB maps obtained by observations always possess domains which have to be masked due to severe uncertainties with respect to the genuine CMB signal. Cosmological analyses ideally use full CMB maps in order to get e.g. the angular power spectrum. There are attempts to reconstruct the masked regions at least at low resolutions, i.e. at large angular scales, before a further analysis follows. In this paper, the quality of the reconstruction is investigated for the ILC (7yr) map as well as for 1000 CMB simulations of the LambdaCDM concordance model. The latter allows an error estimation for the reconstruction algorithm which reveals some drawbacks. The analysis points to errors of the order of a significant fraction of the mean temperature fluctuation of the CMB. The temperature 2-point correlation function C(theta) is evaluated for different reconstructed sky maps which leads to the conclusion that it is safest to compute it on the cut-sky

Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectra

We present the temperature and polarization angular power spectra of the cosmic microwave background (CMB) derived from the first 5 years of WMAP data. The 5-year temperature (TT) spectrum is cosmic variance limited up to multipole l=530, and individual l-modes have S/N>1 for l<920. The best fitting six-parameter LambdaCDM model has a reduced chi^2 for l=33-1000 of chi^2/nu=1.06, with a probability to exceed of 9.3%. There is now significantly improved data near the third peak which leads to improved cosmological constraints. The temperature-polarization correlation (TE) is seen with high significance. After accounting for foreground emission, the low-l reionization feature in the EE power spectrum is preferred by \Delta\chi^2=19.6 for optical depth tau=0.089 by the EE data alone, and is now largely cosmic variance limited for l=2-6. There is no evidence for cosmic signal in the BB, TB, or EB spectra after accounting for foreground emission. We find that, when averaged over l=2-6, l(l+1)C^{BB}_l/2\pi < 0.15 uK^2 (95% CL).Comment: 29 pages, 13 figures, accepted by ApJ

Cross-Correlation Detection of Point Sources in WMAP First Year Data

We apply a Cross-correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. Analyzing this map, we find that the CC method is a powerful tool to examine the WMAP foreground residuals which can be further cleaned accordingly. Evident foreground signals are found in WMAP foreground cleaned maps and Tegmark cleaned map. In this process 101 point-sources are detected, and 26 of them are new sources besides the originally listed WMAP 208 sources. We estimate the flux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.Comment: 14 pages, 10 figures; accepted for publication by ChJA

Time-Periodic Solutions of the Einstein's Field Equations II

In this paper, we construct several kinds of new time-periodic solutions of the vacuum Einstein's field equations whose Riemann curvature tensors vanish, keep finite or take the infinity at some points in these space-times, respectively. The singularities of these new time-periodic solutions are investigated and some new physical phenomena are found. The applications of these solutions in modern cosmology and general relativity can be expected.Comment: 10 pages, 1 figur

Pseudo-Dipole Signal Removal from WMAP Data

It is discovered in our previous work that different observational systematics, e.g., errors of antenna pointing directions, asynchronous between the attitude and science data, can generate pseudo-dipole signal in full-sky maps of the cosmic microwave background (CMB) anisotropy published by The Wilkinson Microwave Anisotropy Probe (WMAP) team. Now the antenna sidelobe response to the Doppler signal is found to be able to produce similar effect as well. In this work, independent to the sources, we uniformly model the pseudo-dipole signal and remove it from published WMAP7 CMB maps by model fitting. The result demonstrates that most of the released WMAP CMB quadrupole is artificial.Comment: V3: using WMAP7 dat

Evaluating the potential contribution of interdisciplinary obstetrics skills/drills emergency training as a quality improvement initiative: self-reported levels of pre and post- test confidence levels

Background High-fidelity simulation is integral to health professional training. The effect of interdisciplinary training on levels of confidence in obstetric emergencies is less well explored. Aim To evaluate the impact of a multidisciplinary training project in obstetric emergency skills and drills on the confidence of staff. Methods A mixed-methods approach was used to evaluate the self-reported confidence levels of obstetrics staff. A total of 69 staff voluntarily attended emergency skills and drills training with a birthing simulator manikin. The programme used four emergency scenarios that had potential for poor maternal outcomes. A debrief followed each scenario and confidence levels were self-reported before and after each training session