A likelihood ratio test for functional MRI data analysis to account for colored noise

Abstract. Functional magnetic resonance (fMRI) data are often corrupted with colored noise. To account for this type of noise, many prewhitening and pre-coloring strategies have been proposed to process the fMRI time series prior to statistical inference. In this paper, a generalized likelihood ratio test for brain activation detection is proposed in which the temporal correlation structure of the noise is modelled as an autoregressive (AR) model. The order of the AR model is determined from experimental null data sets. Simulation tests reveal that, for a fixed false alarm rate, the proposed test is slightly (2-3%) better than current tests incorporating colored noise in terms of detection rate

Adaptive nonlinear fringe-adjusted joint transform correlator

International audienceAn optimized technique based on the fringe-adjustedJTC (joint transform correlator) architecture is proposed and validated for rotation invariant recognition and tracking of a target in an unknown input scene. To enhance the robustness of the proposed technique, we used a three-step optimization by: (1) utilizing the fringe-adjusted filter (HFAF) in the Fourier plane, (2) adding nonlinear processing in the Fourier plane, and (3) using a new decision criterion in the correlation plane by considering the correlation peak energy and the highest peaks outside the desired correlation peak. Several tests were conducted to reduce the number of reference images needed for fast tracking while ensuring robust discrimination and efficient tracking of thedesired target. Test results obtained using the PHPID (Pointing Head Pose Image Database) data baseconfirm robust performance of the proposed method for face recognition and tracking applications. Thereafter, we also tested the proposed technique for a challenging application i.e. underwater mine detection and excellent results were obtained

NLO differential distributions of massive lepton-pair production in longitudinally polarized proton-proton collisions

We present the full next-to-leading order (NLO) corrected inclusive cross section $d^3\Delta \sigma/dQ^2/dy/dp_T$ for massive lepton pair production in longitudinally polarized proton-proton collisions $p + p\to l^+l^- + 'X'$. Here $'X'$ denotes any inclusive hadronic state and Q represents the invariant mass of the lepton pair which has transverse momentum p_T and rapidity y. All QCD partonic subprocesses have been included provided the lepton pair is created by a virtual photon, which is a valid approximation for $Q<50{\rm GeV}$. Like in unpolarized proton-proton scattering the dominant subprocess is given by $q(\bar q) + g \to \gamma^* + 'X'$ so that massive lepton pair production provides us with an excellent method to measure the spin density of the gluon. Our calculations are carried out using the method of n-dimensional regularization by making a special choice for the $\gamma_5$-matrix. Like in the case of many other prescriptions evanescent counter terms appear. They are determined by computing the NLO coefficient functions for $d\Delta\sigma/dQ^2$ and the polarized cross section for Higgs production using both n-dimensional regularization and a four dimensional regularization technique in which the $\gamma_5$-matrix is uniquely defined. Our calculations reveal that the non-singlet polarized coefficient function equals the unpolarized one up to a minus sign. We give predictions for double longitudinal spin asymmetry measurements at the RHIC.Comment: 56 pages, LaTeX, 20 postscript figures. We have changed the discussion of the various regularization schemes in the penultimate paragraph of section 1 and in the text between Eq. (2.17) and Eq. (2.18). Furthermore a more careful comparison between our results and those in refs. [13],[14] for the quark-anti-quark channel reveals that we have full agreement. Further some misprints like the ones occuring in Eq. (2.61) and table 1 in section 4 are correcte

Imaging of pediatric great vessel stents: Computed tomography or magnetic resonance imaging?

__Background:__ Complications might occur after great vessel stent implantation in children. Therefore follow- up using imaging is warranted. __Purpose:__ To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children. __Material and methods:__ Five different large vessel stents were evaluated in an in-vitro setting. All stents were expanded to the maximal vendor recommended diameter (20mm; n = 4 or 10mm; n = 1), placed in an anthropomorphic chest phantom and imaged with a 256-slice CT-scanner. MRI images were acquired at 1.5T using a multi-slice T2-weighted turbo spin echo, an RFspoiled three-dimensional T1-weighted Fast Field Echo and a balanced turbo field echo 3D seq

Change of bilateral difference in radial artery pulse morphology with one-side arm movement

Previous studies have demonstrated that the compliance of peripheral artery changes with arm movement. This study aimed to quantify the bilateral difference in radial artery pulse morphology with one-side arm movement. Twenty-four healthy subjects were recruited. Radial artery pulses were synchronously recorded from both arms, with one arm (left or right) at five different positions (90°, 45°, 0°, −45° and −90°) and the other arm at horizontal level (0°) as reference. Two types of indices of arterial pulse morphology were derived from the normalized arterial pulse signals: the waveform width corresponding to the 50%, 60% and 70% pulse amplitude (W50, W60, W70) and the total area of normalized pulse waveform (Apulse). No matter whether the moving arm was left or right arm, when compared with the other side reference arm, all the waveform widths decreased with arm moving from 90°, 45°, 0°, −45°, and −90°. The bilateral difference of W50, W60 and W70 with the moving arm (either left or right) at 90°, 45° were significantly positive (both p < 0.01) and significantly negative at −90° (both p < 0.05). Meanwhile, no matter whether the moving arm is left or right, Apulse decreased with arm moving from 90°, 45°, 0°, −45°, and −90°. The bilateral difference of Apulse with the left moving arm were significantly positive at 45°, 90° (both p < 0.05). Meanwhile, the bilateral difference of Apulse from the moving right arm was significantly positive at 90° and significantly negative at −45° and −90° (all p < 0.05). In summary, this study quantified the bilateral arterial pulse morphology between arteries with different compliances induced by a simple arm positioning procedure

Guidance on the Selection of Appropriate Indicators for Quantification of Antimicrobial Usage in Humans and Animals

An increasing variety of indicators of antimicrobial usage has become available in human and veterinary medicine, with no consensus on the most appropriate indicators to be used. The objective of this review is therefore to provide guidance on the selection of indicators, intended for those aiming to quantify antimicrobial usage based on sales, deliveries or reimbursement data. Depending on the study objective, different requirements apply to antimicrobial usage quantification in terms of resolution, comprehensiveness, stability over time, ability to assess exposure and comparability. If the aim is to monitor antimicrobial usage trends, it is crucial to use a robust quantification system that allows stability over time in terms of required data and provided output; to compare usage between different species or countries, comparability must be ensured between the different populations. If data are used for benchmarking, the system comprehensiveness is particularly crucial, while data collected to study the association between usage and resistance should express the exposure level and duration as a measurement of the exerted selection pressure. Antimicrobial usage is generally described as the number of technical units consumed normalized by the population at risk of being treated in a defined period. The technical units vary from number of packages to number of individuals treated daily by adding different levels of complexity such as daily dose or weight at treatment. These technical units are then related to a description of the population at risk, based either on biomass or number of individuals. Conventions and assumptions are needed for all of these calculation steps. However, there is a clear lack of standardization, resulting in poor transparency and comparability. By combining study requirements with available approaches to quantify antimicrobial usage, we provide suggestions on the most appropriate indicators and data sources to be used for a given study objective

Historical Y. pestis Genomes Reveal the European Black Death as the Source of Ancient and Modern Plague Pandemics

© 2016 Elsevier Inc.Ancient DNA analysis has revealed an involvement of the bacterial pathogen Yersinia pestis in several historical pandemics, including the second plague pandemic (Europe, mid-14th century Black Death until the mid-18th century AD). Here we present reconstructed Y. pestis genomes from plague victims of the Black Death and two subsequent historical outbreaks spanning Europe and its vicinity, namely Barcelona, Spain (1300-1420 cal AD), Bolgar City, Russia (1362-1400 AD), and Ellwangen, Germany (1485-1627 cal AD). Our results provide support for (1) a single entry of Y. pestis in Europe during the Black Death, (2) a wave of plague that traveled toward Asia to later become the source population for contemporary worldwide epidemics, and (3) the presence of an historical European plague focus involved in post-Black Death outbreaks that is now likely extinct

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations