We describe a novel probabilistic framework for real-time tracking of multiple objects from combined depth-colour imagery. Object shape is represented implicitly using 3D signed distance functions. ...Probabilistic generative models based on these functions are developed to account for the observed RGB-D imagery, and tracking is posed as a maximum a posteriori problem. We present first a method suited to tracking a single rigid 3D object, and then generalise this to multiple objects by combining distance functions into a shape union in the frame of the camera. This second model accounts for similarity and proximity between objects, and leads to robust real-time tracking without recourse to bolt-on or ad-hoc collision detection.
1. Using data from a 20-year study of individually marked red-billed choughs, we examine how reproductive performance varies with age in male and female breeders, and investigate whether ...population-level trends result from changes in individual performance and/or the phenotypic composition of the breeding population. 2. Across the population, mean clutch size, the probability of breeding successfully and the number of offspring fledged during successful attempts increased and then declined with female age. Male age did not explain a significant proportion of the residual variation. 3. All three measures of reproductive performance improved and then declined with age within individual females. 4. Females that died young laid relatively small clutches and fledged few offspring before death. Thus mean performance improved across young age classes partly because some poor breeders were absent from older age classes. 5. Females that ultimately reached the greatest ages had laid small clutches and fledged few offspring during their first few breeding attempts. Females that were more productive when they were young had relatively shorter lives. These data indicate a trade-off between early reproduction and future survival in choughs, and suggest that individuals that reach old age are phenotypically distinct from an early stage in their breeding lives. 6. We emphasize that age-specific changes in mean reproductive performance observed across wild populations are due to a complex interplay between improvement and senescence at the individual level, as well as changes in the phenotypic composition of the breeding population.
Two laccase isozymes (I and II) produced by the white-rot fungus Trametes versicolor were purified, and their reactivities towards various substrates and lignins were studied. The N-terminal amino ...acid sequences of these enzymes were determined and compared to other known laccase sequences. Laccase II showed a very high sequence similarity to a laccase which was previously reported to depolymerize lignin. The reactivities of the two isozymes on most of the substrates tested were similar, but there were some differences in the oxidation rate of polymeric substrates. We found that the two laccases produced similar qualitative effects on kraft lignin and residual lignin in kraft pulp, with no evidence of a marked preference for depolymerization by either enzyme. However, the presence of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) prevented and reversed the polymerization of kraft lignin by either laccase. The delignification of hardwood and softwood kraft pulps with the two isozymes and the mediator was compared; either laccase was able to reduce the kappa number of pulp, but only in the presence of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate).
Human campylobacteriosis exhibits a distinctive seasonality in temperate regions. This paper aims to identify the origins of this seasonality. Clinical isolates typed by multi-locus sequence typing ...(MLST) and epidemiological data were collected from Scotland. Young rural children were found to have an increased burden of disease in the late spring due to strains of non-chicken origin (e.g. ruminant and wild bird strains from environmental sources). In contrast the adult population had an extended summer peak associated with chicken strains. Travel abroad and UK mainland travel were associated with up to 17% and 18% of cases, respectively. International strains were associated with chicken, had a higher diversity than indigenous strains and a different spectrum of MLST types representative of these countries. Integrating empirical epidemiology and molecular subtyping can successfully elucidate the seasonal components of human campylobacteriosis. The findings will enable public health officials to focus strategies to reduce the disease burden.
1. The consequences of environmental variability for life-history evolution are predicted to depend on the pattern of covariation amongst life-history traits. Using data from a 20-year study of ...individually marked red-billed choughs, we investigate the short- and long-term life-history consequences of population-wide variation in reproductive conditions, and demonstrate clear among-cohort variation and covariation in life-history parameters. 2. The mean number of offspring fledging per breeding event varied among years, and was correlated with environmental conditions (temperature and rainfall) during the months preceding breeding. As the variance in breeding performance did not differ among years and choughs did not miss breeding seasons, variation in environmental conditions affected the whole breeding population. Thus the quality of the chough's breeding environment varied amongst years. 3. Juvenile survival, the probability of recruitment to the breeding population and breeding longevity varied amongst cohorts, and these were positively correlated with the quality of the cohort's natal environment. Offspring fledging under good conditions were more likely to survive to breeding age and recruit, and had longer breeding lives than offspring fledging under poor conditions. 4. Age at first breeding varied amongst cohorts, and increased with population size at maturity rather than natal conditions. 5. The total number of offspring that recruits ultimately fledged varied primarily with breeding longevity rather than recruitment age. Thus, the consistent positive covariation amongst life-history traits meant that the total number of offspring fledged by recruits during their breeding life varied amongst cohorts, and was correlated with the quality of a cohort's natal conditions. Choughs fledging under good conditions themselves ultimately fledged more offspring. 6. Such environmentally determined variation in offspring fitness is expected to influence optimal patterns of parental investment. We discuss the predictions that environmental variability should select for investment in adult survival and for reduced reproductive effort in poor years.
MonoSLAM: Real-Time Single Camera SLAM Davison, A.J.; Reid, I.D.; Molton, N.D. ...
IEEE transactions on pattern analysis and machine intelligence,
06/2007, Letnik:
29, Številka:
6
Journal Article
Recenzirano
Odprti dostop
We present a real-time algorithm which can recover the 3D trajectory of a monocular camera, moving rapidly through a previously unknown scene. Our system, which we dub MonoSLAM, is the first ...successful application of the SLAM methodology from mobile robotics to the "pure vision" domain of a single uncontrolled camera, achieving real time but drift-free performance inaccessible to structure from motion approaches. The core of the approach is the online creation of a sparse but persistent map of natural landmarks within a probabilistic framework. Our key novel contributions include an active approach to mapping and measurement, the use of a general motion model for smooth camera movement, and solutions for monocular feature initialization and feature orientation estimation. Together, these add up to an extremely efficient and robust algorithm which runs at 30 Hz with standard PC and camera hardware. This work extends the range of robotic systems in which SLAM can be usefully applied, but also opens up new areas. We present applications of MonoSLAM to real-time 3D localization and mapping for a high-performance full-size humanoid robot and live augmented reality with a hand-held camera
Implementing a 3D histogram version of the Energy-Test in ROOT Cohen, E.O.; Reid, I.D.; Piasetzky, E.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2016, Letnik:
828
Journal Article
Recenzirano
Odprti dostop
Comparing simulation and data histograms is of interest in nuclear and particle physics experiments; however, the leading three-dimensional histogram comparison tool available in ROOT, the 3D ...Kolmogorov–Smirnov test, exhibits shortcomings. Throughout the following, we present and discuss the implementation of an alternative comparison test for three-dimensional histograms, based on the Energy-Test by Aslan and Zech. The software package can be found at http://www-nuclear.tau.ac.il/ecohen/.
Free induction decay signals emitted from Carbon Monoxide (CO) excited by sub-picosecond pulses of Terahertz (THz) radiation are directly measured in the time domain and compared to model ...calculations using a linear dispersion model to good agreement. Best fitting techniques of the data using the model allow the self-pressure broadening of CO to be measured across a range of absolute pressures, and the rotational constant to be determined. We find
B
V
= 5.770 ± 0.003 × 10
10
Hz in agreement with previous measurements. A partial pressure limit of detection for CO of 7900 ppm is estimated at atmosphere through extrapolating the calculated commensurate echo peaks down to low pressures with respect to the RMS noise floor of our THz time domain spectroscopy (THz-TDS) apparatus, which implies a limit of detection in the range of 40 ppm for commercial THz-TDS systems.
1. Understanding the pattern and magnitude of spatial variation in demography and population growth rate (λ) is key to understanding the structure and dynamics of natural populations. However, such ...spatial variation is challenging to quantify. We use > 20 years of individual life-history data to quantify small- and large-scale spatial variation in demography and λ within a single population of red-billed choughs Pyrrhocorax pyrrhocorax on Islay, Scotland. Critically, we demonstrate a major importance of an individual's natal rather than current location in driving observed spatial variation. 2. Breeding success (the number of offspring fledged per breeding attempt) varied among individual chough nest sites but did not vary on a larger spatial scale across Islay. 3. The proportion of fledglings observed to survive to recruiting age varied markedly among individual nest sites and also varied more widely across Islay. Spatial capture-mark-recapture models defined two discrete geographical regions where fledgling survival differed significantly: choughs fledged in region 'BGE' were more likely to survive than choughs fledged in region 'CNSW' as both subadults and adults. 4. The asymptotic λ attributable to breeding attempts in region BGE exceeded unity, and exceeded that attributable to breeding attempts in region CNSW. Relatively productive and unproductive regions therefore exist within this population. 5. Spatial variation in adult survival was better explained by an individual's natal region than the region where that individual settled to breed. Spatial variation in λ would consequently have remained undetected had survival been measured across resident breeders rather than across individuals fledged in each region. Furthermore, breeding success was a weak predictor of a nest site's estimated productivity of recruits. 6. We therefore describe marked spatial variation in demography and λ within a single population of a territorial vertebrate, mediated partly by long-term links between an individual's natal location and its subsequent life-history. Life-long monitoring of individuals of known origin may therefore be necessary to identify accurately subpopulations of intrinsically high and low λ.
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