Automated Detection of Vessel Abnormalities on Fluorescein Angiogram in Malarial Retinopathy

The detection and assessment of intravascular filling defects is important, because they may represent a process central to cerebral malaria pathogenesis: neurovascular sequestration. We have developed and validated a framework that can automatically detect intravascular filling defects in fluorescein angiogram images. It first employs a state-of-the-art segmentation approach to extract the vessels from images and then divide them into individual segments by geometrical analysis. A feature vector based on the intensity and shape of saliency maps is generated to represent the level of abnormality of each vessel segment. An AdaBoost classifier with weighted cost coefficient is trained to classify the vessel segments into normal and abnormal categories. To demonstrate its effectiveness, we apply this framework to 6,358 vessel segments in images from 10 patients with malarial retinopathy. The test sensitivity, specificity, accuracy, and area under curve (AUC) are 74.7%, 73.5%, 74.1% and 74.2% respectively when compared to the reference standard of human expert manual annotations. This performance is comparable to the agreement that we find between human observers of intravascular filling defects. Our method will be a powerful new tool for studying malarial retinopathy

Scalar resonances: scattering and production amplitudes

Scattering and production amplitudes involving scalar resonances are known, according to Watson's theorem, to share the same phase $\delta(s)$. We show that, at low energies, the production amplitude is fully determined by the combination of $\delta(s)$ with another phase $\omega(s)$, which describes intermediate two-meson propagation and is theoretically unambiguous. Our main result is a simple and almost model independent expression, which generalizes the usual $K$-matrix unitarization procedure and is suited to be used in analyses of production data involving scalar resonances.Comment: 10 pages, 4 figures. Minor changes, references added, version to appear in Phys. Rev.

ANALISA TINGKAT KERUSAKAN JALAN MENGGUNAKAN METODE PCI (PAVEMENT CONDITION INDEX) DAN APLIKASI SISTEM INFORMASI GEOGRAFIS PADA RUAS JALAN SANGA SANGA - DONDANG

Road damage that occurs in various areas, especially in the Sanga Sanga - Dondang area, Kutai Kartanegara Regency is a very complex problem and the losses suffered are quite large, especially for road users, such as long travel times and traffic accidents. The cause of road damage that occurs in the Sanga Sanga - Dondang road section is the burden of excessive traffic (overloaded) and the slow handling of existing damage so that it becomes more severe. The method used in this survey is a method of visual analysis based on the Pavement Condition Index (PCI) method. The Pavement Condition Index (PCI) method is used to identify damage to the road surface based on the survey results, so that appropriate and efficient handling of repairs can be identified in the study. the Sanga Sanga - Dondang road section and the Geographic Information System (GIS) application function to facilitate the presentation of damage information in the form of maps. The most dense damage to the Sanga Sanga - Dondang Sta 0 + 000 - 18 + 000 road segment, especially in segments 1 to 11, Potholes, Alligator cracking, Weathering, Edge cracking and Patching. The average pavement condition index (PCI) value of the Sanga Sanga - Dondang road section is 33% based on the existing classification, the road segment is classified as poor (Poor) and refers to the PCI matrix for Class I Arterial Roads, the road needs to be done. reconstructed

Optical-uv spectrum and proper motion of the middle-aged pulsar b1055-52

PSRB1055-52 is a middle-aged (~535 kyr) radio, X-ray, and gamma-ray pulsar showing X-ray thermal emission from the neutron star (NS) surface. A candidate optical counterpart to PSRB1055-52 was proposed by Mignani and coworkers based on Hubble Space Telescope (HST) observations performed in 1996, in one spectral band only. We report on HST observations of this field carried out in 2008, in four spectral bands. The astrometric and photometric analyses of these data confirm the identification of the proposed candidate as the pulsar's optical counterpart. Similarly to other middle-aged pulsars, its optical-UV spectrum can be described by the sum of a power-law (PLO) component, presumably emitted from the pulsar magnetosphere, and a Rayleigh-Jeans (RJ) component emitted from the NS surface. The spectral index of the PLO component, alpha_O=1.05+/-0.34, is larger than for other pulsars with optical counterparts. The RJ component, with the brightness temperature TO=(0.66+/-0.10) d_350**2 R_O,13**-2 MK (where d_350 and R_O,13 are the distance to the pulsar in units of 350 pc and the radius of the emitting area in units of 13 km), shows a factor of 4 excess with respect to the extrapolation of the X-ray thermal component into the UV-optical. This hints that the RJ component is emitted from a larger, colder area, and suggests that the distance to the pulsar is smaller than previously thought. From the absolute astrometry of the HST images we measured the pulsar coordinates with a position accuracy of 0.15". From the comparison with previous observations we measured the pulsar proper motion, mu = 42+/-5 mas/yr, which corresponds to a transverse velocity V_t = (70+/-8) d_350 km/s.Comment: 12 pages, 5 figures, accepted for publication on Astrophysical Journal, (Fig1a available at http://www.mssl.ucl.ac.uk/~rm2/