Busy Beaver Scores and Alphabet Size

We investigate the Busy Beaver Game introduced by Rado (1962) generalized to non-binary alphabets. Harland (2016) conjectured that activity (number of steps) and productivity (number of non-blank symbols) of candidate machines grow as the alphabet size increases. We prove this conjecture for any alphabet size under the condition that the number of states is sufficiently large. For the measure activity we show that increasing the alphabet size from two to three allows an increase. By a classical construction it is even possible to obtain a two-state machine increasing activity and productivity of any machine if we allow an alphabet size depending on the number of states of the original machine. We also show that an increase of the alphabet by a factor of three admits an increase of activity

Application of Predictive Models for Natural Gas Needs - Current State and Future Trends Review

Nowadays, in terms of trading on the world scale, to foresee a natural gas consumption represents an essential activity. In the first part, the paper examines the current state of the Serbian natural gas sector and methodology applied for prediction and capacity planning. In addition, the study intends to give a comprehensive assessment of predictive algorithms for natural gas needs involved in the last decade with projections and suggestions for future applications. The primary task is to evaluate used predictive models with an emphasis on the accuracy of the predictions obtained. Additionally, the paper will analyse used parameters, consumption scale, prediction scope, forecast algorithms, and other related information. The main objective of this study is to review the new-fangled information related analyses data from peer-reviewed journals, international conferences, and books

Stability of Bose Einstein condensates of hot magnons in YIG

We investigate the stability of the recently discovered room temperature Bose-Einstein condensate (BEC) of magnons in Ytrrium Iron Garnet (YIG) films. We show that magnon-magnon interactions depend strongly on the external field orientation, and that the BEC in current experiments is actually metastable - it only survives because of finite size effects, and because the BEC density is very low. On the other hand a strong field applied perpendicular to the sample plane leads to a repulsive magnon-magnon interaction; we predict that a high-density magnon BEC can then be formed in this perpendicular field geometry.Comment: Submitted to Physical Review Letter

Approximating Tverberg Points in Linear Time for Any Fixed Dimension

Let P be a d-dimensional n-point set. A Tverberg-partition of P is a partition of P into r sets P_1, ..., P_r such that the convex hulls conv(P_1), ..., conv(P_r) have non-empty intersection. A point in the intersection of the conv(P_i)'s is called a Tverberg point of depth r for P. A classic result by Tverberg implies that there always exists a Tverberg partition of size n/(d+1), but it is not known how to find such a partition in polynomial time. Therefore, approximate solutions are of interest. We describe a deterministic algorithm that finds a Tverberg partition of size n/4(d+1)^3 in time d^{O(log d)} n. This means that for every fixed dimension we can compute an approximate Tverberg point (and hence also an approximate centerpoint) in linear time. Our algorithm is obtained by combining a novel lifting approach with a recent result by Miller and Sheehy (2010).Comment: 14 pages, 2 figures. A preliminary version appeared in SoCG 2012. This version removes an incorrect example at the end of Section 3.

Biocontrol of potato wilt by selective rhizospheric and endophytic bacteria associated with potato plant

Ralstonia solanacearum is the causative agent of wilt disease in plants, which constitutes a severe problem to agricultural crops, particularly for potato production in Madagascar. The present study focuses on the isolation, in vitro and in vivo assays of potential rhizospheric and endophytic bacteria associated with healthy potato plant, capable to inhibit the growth of Ralstonia solanacearum for controlling potato bacterial wilt. A total of 77 bacteria strains were isolated from six soil rhizospheric samples and six vegetal material samples of healthy potatoes in the district of Antsirabe II. Forty of them were telluric actinomycetes, 25 were endophytic actinomycetes and 12 were fluorescent Pseudomonas spp. An additional 30 phytopathogenic isolates were obtained from six rhizopsheric soil samples of diseased potatoes. Morphological, cultural, biochemical characterization and molecular identification with the Ralstonia solanacearum specific primers 759/760 revealed that 24 of the pathogenic isolates belong to the Ralstonia solanacearum species, biovar two; the causal agent of potato bacterial wilt. Isolates from healthy plants were, then, examined in vitro and in vivo for their antagonistic activity against Ralstonia solanacearum strain for their potential to improve potato plant growth. In vitro antagonism of actinomycete and Pseudomonas isolates against Ralstonia solanacearum development was performed using agar diffusion technique, while in vivo tests were conducted under greenhouse conditions. Ten antagonistic strains including two Pseudomonas, four telluric actinomycetes, and four endophytic actinomycetes inhibited the tested Ralstonia strain. Four strains, E7, E13 (endophytic actinomycete from root potatoes), S25 (telluric actinomycetes) and P7 (fluorescent Pseudomonas), showed high antagonistic activity against the pathogen with zones of inhibition from 23 to 40 mm. Of the fours strains tested in greenhouse, E7 significantly reduced (p < 0.05) the percentage of Ralstonia solanacearum that infected plants by 72.04%. The isolates E13 and S25 have also been demonstrated to improve plant growth by increase of plant height to 44.63% and 44.84%, fresh weight to 68.75% and 75.85% and dry weight to 86.17% and 115.42%, respectively compared with non-treated control. Morphological and cultural characterization of these three active isolates showed that they belong to the genus Streptomyces. The antagonism of these isolates against Ralstonia solanacearum according to in vitro and in vivo tests results, along with their high efficiency as regards the improvement of plant development, suggests that these three actinomycete strains E7, E13 and S25 could be useful for biocontrol of potato bacterial wilt.Key words: Potato, Ralstonia, Actinomycetes, Pseudomonas, Biocontrol

Acid fast bacillus pulmonary and extra pulmonary in a laboratory of university hospital center in Antananarivo, Madagascar since 2003-2014

Background: Tuberculosis has even been a grave public health problem in Madagascar, one of the main causes responsible for death at the hospital for active and productive people.Methods: It was a descriptive and analytical retrospective study of patient records admitted for the research of acid-fast bacillus (AFB) pulmonary and extra pulmonary from January 2003 to December 2014 at the microbiology laboratory of the University Hospital Joseph Ravoahangy Andrianavalona (HU-JRA) Antananarivo, Madagascar. We did this study in order to describe the epidemiology of pulmonary and extra pulmonary tuberculosis at the laboratory. All of the requests about researching AFB for bacterial analysis have been received. Incomplete folders have been rejected. Age, sex, clinic information and the results of AFB research have been analyzed.Results: During 12 years, 1060 requests have been received to research AFB with 89 cases (8.39%) of positivity. Patients were between 9 months and 93 years old. The middle patient age was 41.7 years. Sex-ratio of infected patients was 1.36. There was a significant difference between gender and positive cases (p=0,001). 82 positive cases (93.77%) were pulmonary localization and 7 cases of extra pulmonary (6.23%).Conclusions: Despite the lack of screening, the high rate of bacillary pulmonary tuberculosis found was one of the great epidemiological importances because of their contagiousness. It is obvious that only health actions cannot solve the problem of tuberculosis.

Signature of effective mass in crackling noise asymmetry

Crackling noise is a common feature in many dynamic systems [1-9], the most familiar instance of which is the sound made by a sheet of paper when crumpled into a ball. Although seemingly random, this noise contains fundamental information about the properties of the system in which it occurs. One potential source of such information lies in the asymmetric shape of noise pulses emitted by a diverse range of noisy systems [8-12], but the cause of this asymmetry has lacked explanation [1]. Here we show that the leftward asymmetry observed in the Barkhausen effect [2] - the noise generated by the jerky motion of domain walls as they interact with impurities in a soft magnet - is a direct consequence of a magnetic domain wall's negative effective mass. As well as providing a means of determining domain wall effective mass from a magnet's Barkhausen noise our work suggests an inertial explanation for the origin of avalanche asymmetries in crackling noise phenomena more generally.Comment: 13 pages, 4 figures, to appear in Nature Physic

A robust SNP barcode for typing Mycobacterium tuberculosis complex strains

Strain-specific genomic diversity in the Mycobacterium tuberculosis complex (MTBC) is an important factor in pathogenesis that may affect virulence, transmissibility, host response and emergence of drug resistance. Several systems have been proposed to classify MTBC strains into distinct lineages and families. Here, we investigate single-nucleotide polymorphisms (SNPs) as robust (stable) markers of genetic variation for phylogenetic analysis. We identify ~92k SNP across a global collection of 1,601 genomes. The SNP-based phylogeny is consistent with the gold-standard regions of difference (RD) classification system. Of the ~7k strain-specific SNPs identified, 62 markers are proposed to discriminate known circulating strains. This SNP-based barcode is the first to cover all main lineages, and classifies a greater number of sublineages than current alternatives. It may be used to classify clinical isolates to evaluate tools to control the disease, including therapeutics and vaccines whose effectiveness may vary by strain type