Texture Segmentation by Evidence Gathering

A new approach to texture segmentation is presented which uses Local Binary Pattern data to provide evidence from which pixels can be classified into texture classes. The proposed algorithm, which we contend to be the first use of evidence gathering in the field of texture classification, uses Generalised Hough Transform style R-tables as unique descriptors for each texture class and an accumulator is used to store votes for each texture class. Tests on the Brodatz database and Berkeley Segmentation Dataset have shown that our algorithm provides excellent results; an average of 86.9% was achieved over 50 tests on 27 Brodatz textures compared with 80.3% achieved by segmentation by histogram comparison centred on each pixel. In addition, our results provide noticeably smoother texture boundaries and reduced noise within texture regions. The concept is also a "higher order" texture descriptor, whereby the arrangement of texture elements is used for classification as well as the frequency of occurrence that is featured in standard texture operators. This results in a unique descriptor for each texture class based on the structure of texture elements within the image, which leads to a homogeneous segmentation, in boundary and area, of texture by this new technique

Currency Portfolios and Currency Exchange in a Search Economy

We develop a dual currency search model to study equilibrium currency exchange and the determination of nominal exchange rates. Agents hold portfolios consisting of two distinct currencies. We study equilibria in which the two currencies are identical and equilibria in which the two currencies differ according to their relative purchasing power risk. We use numerical methods to solve for the steady-state distributions of currency portfolios, nominal exchange rates and value functions. When one of the currencies is 'risky', equilibria exist in which the safe currency trades for multiple units of the risky currency with the observed ratio being the nominal exchange rate. However, due to the decentralized trading environment, we obtain a steady state distribution of nominal exchange rates. The mean and variance of the nominal exchange rate distribution are based on the fundamentals of the model and change in predictable ways when the fundamentals change. -- Wir entwickeln ein Modell mit zwei Währungen, um das Gleichgewicht beim Austausch der Währungen und die nominalen Wechselkurse zu bestimmen. Die Wirtschaftssubjekte halten Portfolios, die aus den zwei verschiedenen Währungen bestehen. Wir untersuchen Gleichgewichte, in denen die zwei Währungen identische Eigenschaften haben und Gleichgewichte, in denen sich die zwei Währungen hinsichtlich ihres Kaufkraftrisikos unterscheiden. Es werden numerische Methoden verwendet, um die Verteilungen der Währungsportfolios, der nominalen Wechselkurse und der Wertfunktionen im langfristigen Gleichgewicht zu bestimmen. Wenn eine der Währungen risikobehaftet ist, dann existieren Gleichgewichte, in denen die sichere Währung gegen mehrere Einheiten der risikobehafteten Währung gehandelt wird. Das Austauschverhältnis ist der nominale Wechselkurs. Da der Handel dezentral erfolgt, ergibt sich eine Gleichgewichtsverteilung der Wechselkurse. Der Mittelwert und die Varianz dieser Verteilung hängt von den Fundamentalfaktoren des Modells ab. Wenn sich die Fundamentalfaktoren ändern, dann ändert sich diese Verteilung in vorhersehbarer Weise.

Dual-currency economies as multiple-payment systems

Monetary search models are valuable for studying how a second currency's acceptability arises endogenously in an economy that lacks a stable domestic currency and other more sophisticated payment systems. Search models' basic assumptions (absence of credit, lack of smoothly functioning banking systems, reliance on currency as the sole medium of exchange, and primitive trading environments) are not necessarily consistent with modern financial systems. They do, however, provide good descriptions of transitional and developing economies, particularly in the countries of the former Soviet Union, and may yield helpful policy prescriptions.Money ; Monetary theory

Currency competition in a fundamental model of money

The authors study how two fiat monies, one safe and one risky, compete in a decentralized trading environment. The equilibrium value of the two currencies, their transaction velocities and agents' spending patterns are endogenously determined. The authors derive conditions under which agents holding diversified currency portfolios spend the safe currency first and hold the risky one for later purchases. They also examine when the reverse spending pattern is optimal.Money ; Currency substitution

Meeting radiation dosimetry capacity requirements of population-scale exposures by geostatistical sampling.

BACKGROUND: Accurate radiation dose estimates are critical for determining eligibility for therapies by timely triaging of exposed individuals after large-scale radiation events. However, the universal assessment of a large population subjected to a nuclear spill incident or detonation is not feasible. Even with high-throughput dosimetry analysis, test volumes far exceed the capacities of first responders to measure radiation exposures directly, or to acquire and process samples for follow-on biodosimetry testing. AIM: To significantly reduce data acquisition and processing requirements for triaging of treatment-eligible exposures in population-scale radiation incidents. METHODS: Physical radiation plumes modelled nuclear detonation scenarios of simulated exposures at 22 US locations. Models assumed only location of the epicenter and historical, prevailing wind directions/speeds. The spatial boundaries of graduated radiation exposures were determined by targeted, multistep geostatistical analysis of small population samples. Initially, locations proximate to these sites were randomly sampled (generally 0.1% of population). Empirical Bayesian kriging established radiation dose contour levels circumscribing these sites. Densification of each plume identified critical locations for additional sampling. After repeated kriging and densification, overlapping grids between each pair of contours of successive plumes were compared based on their diagonal Bray-Curtis distances and root-mean-square deviations, which provided criteria ( RESULTS/CONCLUSIONS: We modeled 30 scenarios, including 22 urban/high-density and 2 rural/low-density scenarios under various weather conditions. Multiple (3-10) rounds of sampling and kriging were required for the dosimetry maps to converge, requiring between 58 and 347 samples for different scenarios. On average, 70±10% of locations where populations are expected to receive an exposure ≥2Gy were identified. Under sub-optimal sampling conditions, the number of iterations and samples were increased, and accuracy was reduced. Geostatistical mapping limits the number of required dose assessments, the time required, and radiation exposure to first responders. Geostatistical analysis will expedite triaging of acute radiation exposure in population-scale nuclear events

Eating behaviours, menstrual history and the athletic career : a retrospective survey from adolescence to adulthood in female endurance athletes

Aim To evaluate differences in menstrual and pubertal history and trends in eating behaviours among women with and without a competitive sports background. Additionally, we investigated if menstrual history and eating behaviours are associated with sports career-related factors.Methods This retrospective study was conducted on 100 women with a competitive endurance sports background and their age-matched, gender-matched and municipality-matched controls (n=98). Data were collected using a questionnaire using previously validated instruments. Generalised estimating equations were used to calculate associations of menstrual history and eating behaviours with outcome variables (career length, participation level, injury-related harms and career termination due to injury).Results Athletes reported higher rates of delayed puberty and menstrual dysfunction than controls. No differences between the groups were observed in the Eating Disorder Examination Questionnaire short form (EDE-QS) scores at any age. Previous disordered eating (DE) was associated with current DE in both groups. Among athletes, higher EDE-QS scores during the sports career were associated with a shorter career (B=-0.15, 95% CI -0.26 to -0.05). Secondary amenorrhoea was associated with lower participation level (OR 0.51, 95% CI 0.27 to 0.95), injury-related harms during the career (OR 4.00, 95% CI 1.88 to 8.48) and career termination due to injury (OR 1.89, 95% CI 1.02 to 3.51).Conclusion The findings indicate that DE behaviours and menstrual dysfunction, specifically secondary amenorrhoea, have a disadvantageous relationship with a sports career in women competing in endurance sports. DE during the sports career is associated with DE after the career.Peer reviewe

The Orphan Adhesion-GPCR GPR126 Is Required for Embryonic Development in the Mouse

Adhesion-GPCRs provide essential cell-cell and cell-matrix interactions in development, and have been implicated in inherited human diseases like Usher Syndrome and bilateral frontoparietal polymicrogyria. They are the second largest subfamily of seven-transmembrane spanning proteins in vertebrates, but the function of most of these receptors is still not understood. The orphan Adhesion-GPCR GPR126 has recently been shown to play an essential role in the myelination of peripheral nerves in zebrafish. In parallel, whole-genome association studies have implicated variation at the GPR126 locus as a determinant of body height in the human population. The physiological function of GPR126 in mammals is still unknown. We describe a targeted mutation of GPR126 in the mouse, and show that GPR126 is required for embryonic viability and cardiovascular development