On Rigidity of 3d Asymptotic Symmetry Algebras

We study rigidity and stability of infinite dimensional algebras which are not subject to the Hochschild-Serre factorization theorem. In particular, we consider algebras appearing as asymptotic symmetries of three dimensional spacetimes, the BMS3, u(1) Kac-Moody and Virasoro algebras. We construct and classify the family of algebras which appear as deformations of BMS3, u(1) Kac-Moody and their central extensions by direct computations and also by cohomological analysis. The Virasoro algebra appears as a specific member in this family of rigid algebras; for this case stabilization procedure is inverse of the In\"on\"u-Wigner contraction relating Virasoro to BMS3 algebra. We comment on the physical meaning of deformation and stabilization of these algebras and relevance of the family of rigid algebras we obtainComment: 50 pages, one figure and two tables; v2: minor improvements, references adde

A satellite-based global landslide model

Landslides are devastating phenomena that cause huge damage around the world. This paper presents a quasi-global landslide model derived using satellite precipitation data, land-use land cover maps, and 250 m topography information. This suggested landslide model is based on the Support Vector Machines (SVM), a machine learning algorithm. The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) landslide inventory data is used as observations and reference data. In all, 70% of the data are used for model development and training, whereas 30% are used for validation and verification. The results of 100 random subsamples of available landslide observations revealed that the suggested landslide model can predict historical landslides reliably. The average error of 100 iterations of landslide prediction is estimated to be approximately 7%, while approximately 2% false landslide events are observed

Expected Number of Real Zeros of a Random Polynomial With Independent Identically Distributed Symmetric Long-Tailed Coefficients

We show that the expected number of real zeros of the nth degree polynomial with real independent identically distributed coefficients with common characteristic function φ(z) = e-A(ln|1/z|)^-a for 0 \u3c |z| \u3c 1 and φ(0) = 1, φ(z) ≡ 0 for 1 ≦ |z| \u3c ∞, with 1 \u3c a and A ≧ a(a-1), is (a-1)/(a-1/2) log(n) asymptotically as n → ∞

Mitigation of liquefaction seismic risk by preloading

Hazard

Phase diagram of fluid phases in 3{}^3He -4{}^4He mixtures

Fluid parts of the phase diagram of ${}^3$He -${}^4$He mixtures are obtained from a mean-field analysis of a suitable lattice gas model for binary liquid mixtures. The proposed model takes into account the continuous rotational symmetry O(2) of the superfluid degrees of freedom associated with ${}^4$He and includes the occurrence of vacancies. This latter degree of freedom allows the model to exhibit a vapor phase and hence can provide the theoretical framework to describe the experimental conditions for measurements of tricritical Casimir forces in ${}^3$He -${}^4$He wetting films

Evaluating the effects of climate on weathering processes of rocks based on Peltier models in Kermanshah province

Weathering is a result of physical, chemical and biological factors, all of which affect the rocks but do not cause Material Handling. The existence of pores and crevices and cracks in the rocks expose the rocks to physical and chemical attack, gradual wracking and being weathered. This study has been based on Louis Peltier’s models in which two mean annual temperature and precipitation variables are used. Peltier identified seven models using these two variables which can describe different types of weathering phenomena. Among these models, two models related to weathering regimes and morphogenetic regimes were evaluated in case of Kermanshah province and the regimes related to each station were determined from the related diagrams. Climate data such as mean annual temperature and precipitation and eight synoptic stations which had appropriate data and statistical length were taken from meteorological organization and then were recorded in a database in GIS environment for studying and zoning of the weathering status and geomorphological regions in Kermanshah. Then, the regimes relating to each station were determined from Peltier models after evaluation of temperature and precipitation processes in the study area which were recorded in the database after giving weighted value to them and then the related maps were generated in ARC map environment. The obtained results showed that most parts of Kermanshah province are semi-arid regions. Chemical weathering along with glacial action to moderate chemical weathering take place in in Kermanshah province in terms of weathering status.Keywords: Weathering regimes, Peltier model, morphogenetic regions, Kermanshah

Statistics of the Number of Zero Crossings : from Random Polynomials to Diffusion Equation

We consider a class of real random polynomials, indexed by an integer d, of large degree n and focus on the number of real roots of such random polynomials. The probability that such polynomials have no real root in the interval [0,1] decays as a power law n^{-\theta(d)} where \theta(d)>0 is the exponent associated to the decay of the persistence probability for the diffusion equation with random initial conditions in space dimension d. For n even, the probability that such polynomials have no root on the full real axis decays as n^{-2(\theta(d) + \theta(2))}. For d=1, this connection allows for a physical realization of real random polynomials. We further show that the probability that such polynomials have exactly k real roots in [0,1] has an unusual scaling form given by n^{-\tilde \phi(k/\log n)} where \tilde \phi(x) is a universal large deviation function.Comment: 4 pages, 3 figures. Minor changes. Accepted version in Phys. Rev. Let

Working memory and response inhibition in patients with bipolar I disorder during euthymic period

Background: Several cognitive domains, including attention, memory, and executive functions are impaired in bipolar disorder. Objectives: This study aimed to investigate two executive functions (working memory and response inhibition) in patients with bipolar I disorder during remission of the symptoms. Patients and Methods: In this case-control design, 30 bipolar I patients (18 to 45 years old) were matched with 30 ones in the control group in terms of age, gender, and education. The patients were selected from Roozbeh Psychiatric Hospital (a hospital affiliated to Tehran University of Medical Sciences) from May to October 2013. They were evaluated and contrasted using working memory (Spatial Span and Spatial Working Memory (SSP and SWM)) and response inhibition (Stop Signal Task (SST)) tests. Results: We used independent t-tests for comparing and contrasting 2 groups on total and sub-scales scores of these 3 tests. In terms of SWM test there was a significant difference in between-group error between the two groups (P = 0.05); there was also a meaningful difference between the strategies used by two groups (P = 0.05). In SSP test, a significant difference appeared between averages of span length of the two groups. In the first and last item delays, there was also a clear difference, but the total error index was not noticeably different. In SST test, the direction error indicator in start-stop trials indicated a major difference, while in successful stops ratio, the case group had a lower ratio. In addition, reaction time to stop signs in bipolar group was meaningfully lower than the control group. Conclusion: In conclusion, even during remission phase, executive dysfunction is detectable at least in some areas in patients with bipolar disorder. © 2015, Mazandaran University of Medical Sciences