Autocalibration with the Minimum Number of Cameras with Known Pixel Shape

In 3D reconstruction, the recovery of the calibration parameters of the cameras is paramount since it provides metric information about the observed scene, e.g., measures of angles and ratios of distances. Autocalibration enables the estimation of the camera parameters without using a calibration device, but by enforcing simple constraints on the camera parameters. In the absence of information about the internal camera parameters such as the focal length and the principal point, the knowledge of the camera pixel shape is usually the only available constraint. Given a projective reconstruction of a rigid scene, we address the problem of the autocalibration of a minimal set of cameras with known pixel shape and otherwise arbitrarily varying intrinsic and extrinsic parameters. We propose an algorithm that only requires 5 cameras (the theoretical minimum), thus halving the number of cameras required by previous algorithms based on the same constraint. To this purpose, we introduce as our basic geometric tool the six-line conic variety (SLCV), consisting in the set of planes intersecting six given lines of 3D space in points of a conic. We show that the set of solutions of the Euclidean upgrading problem for three cameras with known pixel shape can be parameterized in a computationally efficient way. This parameterization is then used to solve autocalibration from five or more cameras, reducing the three-dimensional search space to a two-dimensional one. We provide experiments with real images showing the good performance of the technique.Comment: 19 pages, 14 figures, 7 tables, J. Math. Imaging Vi

Fe-XANES analyses of Reykjanes Ridge basalts: Implications for oceanic crust's role in the solid Earth oxygen cycle

The cycling of material from Earth's surface environment into its interior can couple mantle oxidation state to the evolution of the oceans and atmosphere. A major uncertainty in this exchange is whether altered oceanic crust entering subduction zones can carry the oxidised signal it inherits during alteration at the ridge into the deep mantle for long-term storage. Recycled oceanic crust may be entrained into mantle upwellings and melt under ocean islands, creating the potential for basalt chemistry to constrain solid Earth–hydrosphere redox coupling. Numerous independent observations suggest that Iceland contains a significant recycled oceanic crustal component, making it an ideal locality to investigate links between redox proxies and geochemical indices of enrichment. We have interrogated the elemental, isotope and redox geochemistry of basalts from the Reykjanes Ridge, which forms a 700 km transect of the Iceland plume. Over this distance, geophysical and geochemical tracers of plume influence vary dramatically, with the basalts recording both long- and short-wavelength heterogeneity in the Iceland plume. We present new high-precision Fe-XANES measurements of Fe³⁺/∑Fe on a suite of 64 basalt glasses from the Reykjanes Ridge. These basalts exhibit positive correlations between Fe³⁺/∑Fe and trace element and isotopic signals of enrichment, and become progressively oxidised towards Iceland: fractionation-corrected Fe³⁺/∑Fe increases by ∼0.015 and ΔQFM by ∼0.2 log units. We rule out a role for sulfur degassing in creating this trend, and by considering various redox melting processes and metasomatic source enrichment mechanisms, conclude that an intrinsically oxidised component within the Icelandic mantle is required. Given the previous evidence for entrained oceanic crustal material within the Iceland plume, we consider this the most plausible carrier of the oxidised signal. To determine the ferric iron content of the recycled component ([Fe₂O₃]) we project observed liquid compositions to an estimate of Fe₂O₃ in the pure enriched endmember melt, and then apply simple fractional melting models, considering lherzolitic and pyroxenitic source mineralogies, to estimate [Fe₂O₃] content. Propagating uncertainty through these steps, we obtain a range of [Fe₂O₃] for the enriched melts (0.9–1.4 wt%) that is significantly greater than the ferric iron content of typical upper mantle lherzolites. This range of ferric iron contents is consistent with a hybridised lherzolite–basalt (pyroxenite) mantle component. The oxidised signal in enriched Icelandic basalts is therefore potential evidence for seafloor–hydrosphere interaction having oxidised ancient mid-ocean ridge crust, generating a return flux of oxygen into the deep mantle.OS was supported by a Title A Fellowship from Trinity College, JM through NERC grant NE/J021539/1 and MH acknowledges a Junior Research Fellowship from Murray Edwards College, Cambridge. We acknowledge Diamond Light Source for time on beamline I18 under proposals SP9446, SP9456 and SP12130 and the support during our analytical sessions from beamline scientist Konstantin Ignatyev and principal beamline scientist Fred Mosselmans. The Smithsonian Institution National Museum of Natural History is thanked for their loan of NMNH 117393.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.epsl.2015.07.01

Guest Editorial Cardiovascular Health Informatics: Risk Screening and Intervention

Despite enormous efforts to prevent cardiovascular disease (CVD) in the past, it remains the leading cause of death in most countries worldwide. Around two-thirds of these deaths are due to acute events, which frequently occur suddenly and are often fatal beforemedical care can be given. New strategies for screening and early intervening CVD, in addition to the conventional methods, are therefore needed in order to provide personalized and pervasive healthcare. In this special issue, selected emerging technologies in health informatics for screening and intervening CVDs are reported. These papers include reviews or original contributions on 1) new potential genetic biomarkers for screening CVD outcomes and high-throughput techniques for mining genomic data; 2) new imaging techniques for obtaining faster and higher resolution images of cardiovascular imaging biomarkers such as the cardiac chambers and atherosclerotic plaques in coronary arteries, as well as possible automatic segmentation, identification, or fusion algorithms; 3) new physiological biomarkers and novel wearable and home healthcare technologies for monitoring them in daily lives; 4) new personalized prediction models of plaque formation and progression or CVD outcomes; and 5) quantifiable indices and wearable systems to measure them for early intervention of CVD through lifestyle changes. It is hoped that the proposed technologies and systems covered in this special issue can result in improved CVD management and treatment at the point of need, offering a better quality of life to the patient

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses

Background: A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011. <p/>Methods: Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs). <p/>Results: 32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m2. MTD was 10 mg/m2; DLTs at 12 (2/4 patients) and 10 mg/m2 (3/12) included thrombocytopenia and febrile neutropenia; diarrhea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1--10 mg/m2. Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion. <p/>Conclusions: TP300 had predictable hematologic toxicity, and diarrhea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage

Fast Outlier Rejection by Using Parallax-Based Rigidity Constraint for Epipolar Geometry Estimation

A novel approach is presented in order to reject correspondence outliers between frames using the parallax-based rigidity constraint for epipolar geometry estimation. In this approach, the invariance of 3-D relative projective structure of a stationary scene over different views is exploited to eliminate outliers, mostly due to independently moving objects of a typical scene. The proposed approach is compared against a well-known RANSAC-based algorithm by the help of a test-bed. The results showed that the speed-up, gained by utilization of the proposed technique as a preprocessing step before RANSAC-based approach, decreases the execution time of the overall outlier rejection, significantly

The role of mass and environment in the build up of the quenched galaxy population since cosmic noon

We conduct the first study of how the relative quenching probability of galaxies depends on environment over the redshift range $0.5 < z < 3$, using data from the UKIDSS Ultra-Deep Survey. By constructing the stellar mass functions for quiescent and post-starburst (PSB) galaxies in high, medium and low density environments to $z = 3$, we find an excess of quenched galaxies in dense environments out to at least $z \sim 2$. Using the growth rate in the number of quenched galaxies, combined with the star-forming galaxy mass function, we calculate the probability that a given star-forming galaxy is quenched per unit time. We find a significantly higher quenching rate in dense environments (at a given stellar mass) at all redshifts. Massive galaxies (M$_* > 10^{10.7}$ M$_{\odot}$) are on average 1.7 $\pm$ 0.2 times more likely to quench per Gyr in the densest third of environments compared to the sparsest third. Finally, we compare the quiescent galaxy growth rate to the rate at which galaxies pass through a PSB phase. Assuming a visibility timescale of 500 Myr, we find that the PSB route can explain $\sim$ 50\% of the growth in the quiescent population at high stellar mass (M$_* > 10^{10.7}$ M$_{\odot}$) in the redshift range $0.5 < z < 3$, and potentially all of the growth at lower stellar masses.Comment: 12 pages, 8 figures. Accepted for publication in MNRA

Long-range pollution transport during the MILAGRO-2006 campaign: a case study of a major Mexico City outflow event using free-floating altitude-controlled balloons

One of the major objectives of the Megacities Initiative: Local And Global Research Observations (MILAGRO-2006) campaign was to investigate the long-range transport of polluted Mexico City Metropolitan Area (MCMA) outflow and determine its downwind impacts on air quality and climate. Six research aircraft, including the National Center for Atmospheric Research (NCAR) C-130, made extensive chemical, aerosol, and radiation measurements above MCMA and more than 1000 km downwind in order to characterize the evolution of the outflow as it aged and dispersed over the Mesa Alta, Sierra Madre Oriental, Coastal Plain, and Gulf of Mexico. As part of this effort, free-floating Controlled-Meteorological (CMET) balloons, commanded to change altitude via satellite, made repeated profile measurements of winds and state variables within the advecting outflow. In this paper, we present an analysis of the data from two CMET balloons that were launched near Mexico City on the afternoon of 18 March 2006 and floated downwind with the MCMA pollution for nearly 30 h. The repeating profile measurements show the evolving structure of the outflow in considerable detail: its stability and stratification, interaction with other air masses, mixing episodes, and dispersion into the regional background. Air parcel trajectories, computed directly from the balloon wind profiles, show three transport pathways on 18–19 March: (a) high-altitude advection of the top of the MCMA mixed layer, (b) mid-level outflow over the Sierra Madre Oriental followed by decoupling and isolated transport over the Gulf of Mexico, and (c) low-level outflow with entrainment into a cleaner northwesterly jet above the Coastal Plain. The C-130 aircraft intercepted the balloon-based trajectories three times on 19 March, once along each of these pathways; in all three cases, peaks in urban tracer concentrations and LIDAR backscatter are consistent with MCMA pollution. In comparison with the transport models used in the campaign, the balloon-based trajectories appear to shear the outflow far more uniformly and decouple it from the surface, thus forming a thin but expansive polluted layer over the Gulf of Mexico that is well aligned with the aircraft observations. These results provide critical context for the extensive aircraft measurements made during the 18–19 March MCMA outflow event and may have broader implications for modelling and understanding long-range transport

Origin of two-band chorus in the radiation belt of Earth.

Naturally occurring chorus emissions are a class of electromagnetic waves found in the space environments of the Earth and other magnetized planets. They play an essential role in accelerating high-energy electrons forming the hazardous radiation belt environment. Chorus typically occurs in two distinct frequency bands separated by a gap. The origin of this two-band structure remains a 50-year old question. Here we report, using NASA's Van Allen Probe measurements, that banded chorus waves are commonly accompanied by two separate anisotropic electron components. Using numerical simulations, we show that the initially excited single-band chorus waves alter the electron distribution immediately via Landau resonance, and suppress the electron anisotropy at medium energies. This naturally divides the electron anisotropy into a low and a high energy components which excite the upper-band and lower-band chorus waves, respectively. This mechanism may also apply to the generation of chorus waves in other magnetized planetary magnetospheres