An Extended Kalman Filter with a Computed Mean Square Error Bound

The paper proposes a new recursive filter for non-linear systems that inherently computes a valid bound on the mean square estimation error. The proposed filter, bound based extended Kalman, (BEKF) is in the form of an extended Kalman filter. The main difference of the proposed filter from the conventional extended Kalman filter is in the use of a computed mean square error bound matrix, to calculate the filter gain, and to serve as bound on the actual mean square error. The paper shows that when the system is linear the proposed filtering algorithm reduces to the conventional Kalman filter. The theory presented in the paper is applicable to a wide class of systems, but if the system is polynomial, then the recently developed theory of positive polynomials considerably simplifies the filter's implementation.Comment: 7 pages, 1 figur

Effect of Xenon gas and foils on a multi-foil insulation

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The miniaturization of thermal installations has been also extended to compact insulations in processes maintained at low or high temperatures, and restricted to minimal heat losses or gains. The current investigation has been conducted experimentally and numerically, aiming to predict the performance of a multi-foil array, in which xenon gas is entrapped between steel foils, separated and supported by widely spaced ceramic particles. A parametric study of the effect of an increased number of foils, as compared to the experimental array, shows the preferred directions to design of such arrays. The performance of an array operated with xenon gas near-atmospheric pressure is compared to the performance of arrays filled with other gases. The low thermal conductivity of xenon gas leads to a lower effective conductivity of the array, as compared to arrays operated with other gases. The equations of conduction and radiation are solved numerically for a wide range of pressures and temperatures. Good agreement with experimental results is achieved.dc201

Disorder and Funneling Effects on Exciton Migration in Tree-Like Dendrimers

The center-bound excitonic diffusion on dendrimers subjected to several types of non-homogeneous funneling potentials, is considered. We first study the mean-first passage time (MFPT) for diffusion in a linear potential with different types of correlated and uncorrelated random perturbations. Increasing the funneling force, there is a transition from a phase in which the MFPT grows exponentially with the number of generations $g$, to one in which it does so linearly. Overall the disorder slows down the diffusion, but the effect is much more pronounced in the exponential compared to the linear phase. When the disorder gives rise to uncorrelated random forces there is, in addition, a transition as the temperature $T$ is lowered. This is a transition from a high-$T$ regime in which all paths contribute to the MFPT to a low-$T$ regime in which only a few of them do. We further explore the funneling within a realistic non-linear potential for extended dendrimers in which the dependence of the lowest excitonic energy level on the segment length was derived using the Time-Dependent Hatree-Fock approximation. Under this potential the MFPT grows initially linearly with $g$ but crosses-over, beyond a molecular-specific and $T$-dependent optimal size, to an exponential increase. Finally we consider geometrical disorder in the form of a small concentration of long connections as in the {\it small world} model. Beyond a critical concentration of connections the MFPT decreases significantly and it changes to a power-law or to a logarithmic scaling with $g$, depending on the strength of the funneling force.Comment: 13 pages, 9 figure

On the joint residence time of N independent two-dimensional Brownian motions

We study the behavior of several joint residence times of N independent Brownian particles in a disc of radius $R$ in two dimensions. We consider: (i) the time T_N(t) spent by all N particles simultaneously in the disc within the time interval [0,t]; (ii) the time T_N^{(m)}(t) which at least m out of N particles spend together in the disc within the time interval [0,t]; and (iii) the time {\tilde T}_N^{(m)}(t) which exactly m out of N particles spend together in the disc within the time interval [0,t]. We obtain very simple exact expressions for the expectations of these three residence times in the limit t\to\infty.Comment: 8 page

Survival and residence times in disordered chains with bias

We present a unified framework for first-passage time and residence time of random walks in finite one-dimensional disordered biased systems. The derivation is based on exact expansion of the backward master equation in cumulants. The dependence on initial condition, system size, and bias strength is explicitly studied for models with weak and strong disorder. Application to thermally activated processes is also developed.Comment: 13 pages with 2 figures, RevTeX4; v2:minor grammatical changes, typos correcte

Residence Time Statistics for Normal and Fractional Diffusion in a Force Field

We investigate statistics of occupation times for an over-damped Brownian particle in an external force field. A backward Fokker-Planck equation introduced by Majumdar and Comtet describing the distribution of occupation times is solved. The solution gives a general relation between occupation time statistics and probability currents which are found from solutions of the corresponding problem of first passage time. This general relationship between occupation times and first passage times, is valid for normal Markovian diffusion and for non-Markovian sub-diffusion, the latter modeled using the fractional Fokker-Planck equation. For binding potential fields we find in the long time limit ergodic behavior for normal diffusion, while for the fractional framework weak ergodicity breaking is found, in agreement with previous results of Bel and Barkai on the continuous time random walk on a lattice. For non-binding potential rich physical behaviors are obtained, and classification of occupation time statistics is made possible according to whether or not the underlying random walk is recurrent and the averaged first return time to the origin is finite. Our work establishes a link between fractional calculus and ergodicity breaking.Comment: 12 page

The yeast Cbk1 kinase regulates mRNA localization via the mRNA-binding protein Ssd1

In the absence of Cbk1 phosphorylation Ssd1-associated mRNAs are redirected from sites of polarized cell growth to stress granules and P-bodies

Applicability of a short/rapid 13C-urea breath test for Helicobacter pylori: retrospective multicenter chart review study

<p>Abstract</p> <p>Background</p> <p>Carbon labeled urea breath tests usually entail a two point sampling with a 20 to 30-minute gap. Our aim was to evaluate the duration of time needed for diagnosing <it>Helicobacter pylori </it>by the BreathID^®System.</p> <p>Methods</p> <p>This is a retrospective multicenter chart review study. Test location, date, delta over baseline, and duration of the entire test were recorded. Consecutively ¹³C urea breath tests results were extracted from the files over a nine year period.</p> <p>Results</p> <p>Of the 12,791 tests results, 35.1% were positively diagnosed and only 0.1% were inconclusive. A statistically significant difference in prevalence among the countries was found: Germany showing the lowest, 13.3%, and Israel the highest, 44.1%. Significant differences were found in time to diagnosis: a positive diagnosis had the shortest and an inconclusive result had the longest. Overall test duration averaged 15.1 minutes in Germany versus approximately 13 minutes in other countries. Diagnosis was achieved after approximately 9 minutes in Israel, Italy and Switzerland, but after 10 on average in the others. The mean delta over baseline value for a negative diagnosis was 1.03 ± 0.86, (range, 0.9 - 5), versus 20.2 ± 18.9, (range, 5.1 - 159.4) for a positive one.</p> <p>Conclusions</p> <p>The BreathID^®System used in diagnosing <it>Helicobacter pylori </it>can safely shorten test duration on average of 10-13 minutes without any loss of sensitivity or specificity and with no test lasting more than 21 minutes.</p

Sacred Rhythms and Political Frequencies: Reading Lefebvre in an Urban House of Prayer

In recent years, Lefebvre’s concept of rhythm analysis has been implied in various ways to critically examine how rhythms are formed, disrupted, and reformed through different urban venues. One theme that this body of knowledge has yet to comprehensively examine, however, is how changes in the urban sphere impact the spatial rhythms of religious institutions in cities, which can be pivotal for understanding how religious institutions are formed as urban public spaces. This article addresses this issue with a rhythm analysis of a particular religious urban locus: a synagogue in the mixed Palestinian and Jewish city of Acre in northern Israel. Based on ethnographic fieldwork and an urban survey, the article discusses how different forms of rhythm making undergo a process of contested synchronization with linear and cyclical rhythms of the city. More specifically, how the ability to forge a space hinges on the ability to maintain a rhythmic cycle of attendance, which, in turn, is not only dependent on the ability to achieve synchronization amongst the needs of the different participants but is also intertwined with the larger linear cycle of urban life as a rhythmic equation that fuses the personal with the political, the linear with the cyclical, and the religious with the urban