Factorizations of Elements in Noncommutative Rings: A Survey

We survey results on factorizations of non zero-divisors into atoms (irreducible elements) in noncommutative rings. The point of view in this survey is motivated by the commutative theory of non-unique factorizations. Topics covered include unique factorization up to order and similarity, 2-firs, and modular LCM domains, as well as UFRs and UFDs in the sense of Chatters and Jordan and generalizations thereof. We recall arithmetical invariants for the study of non-unique factorizations, and give transfer results for arithmetical invariants in matrix rings, rings of triangular matrices, and classical maximal orders as well as classical hereditary orders in central simple algebras over global fields.Comment: 50 pages, comments welcom

The First Comprehensive Photometric Study of the Algol-type System CL Aurigae

We present the first extensive photometric results of CL Aur from our BVRI CCD photometry made on 22 nights from 2003 November through 2005 February. Fifteen new timings of minimum light were obtained. During the past 104 years, the orbital period has varied due to a periodic oscillation superposed on a continuous period increase. The period and semi-amplitude of the oscillation are about 21.6 yrs and 0.0133 d, respectively. This detail is interpreted as a light-travel-time effect due to a low-luminosity K-type star gravitationally bound to the CL Aur close system. Our photometric study indicates that CL Aur is a relatively short-period Algol-type binary with values of q=0.602 and i=88$^\circ$.2. Mass transfer from the secondary to the primary eclipsing component is at least partly responsible for the observed secular period change with a rate of dP/dt = +1.4$\times10^{-7}$ d yr$^{-1}$. A cool spot model has been calculated but we think that an alternative hot-spot model resulting from a gas stream impact on the hot star is more reasonable despite two difficulties with the explanation. Absolute dimensions of the eclipsing system are deduced and its present state is compared with tracks for single star and conservative close binary evolution. Finally, we examine the possible reconciliation of two different calculations of the luminosity of the hot spot and a re-interpretation of the secular term of the period variability.Comment: 26 pages, including 5 figures and 9 tables, accepted for publication in A

Evaluation of the efficiency of vending business and the perspectives of its development in the territory of Tomsk

This article assesses the effectiveness of conducting a vending business in the territory of Tomsk and develops a business plan for creating a network of vending machines for hot drinks. During the study, the authors conducted a sociological survey, the purpose of which was to identify the gastronomic preferences of potential buyers and to determine the presence or absence of demand in the market of vending trade. Also, the advantages and disadvantages of this market niche, possible problems and prospects for its development are considered

The secret world of shrimps: polarisation vision at its best

Animal vision spans a great range of complexity, with systems evolving to detect variations in optical intensity, distribution, colour, and polarisation. Polarisation vision systems studied to date detect one to four channels of linear polarisation, combining them in opponent pairs to provide intensity-independent operation. Circular polarisation vision has never been seen, and is widely believed to play no part in animal vision. Polarisation is fully measured via Stokes' parameters--obtained by combined linear and circular polarisation measurements. Optimal polarisation vision is the ability to see Stokes' parameters: here we show that the crustacean \emph{Gonodactylus smithii} measures the exact components required. This vision provides optimal contrast-enhancement, and precise determination of polarisation with no confusion-states or neutral-points--significant advantages. We emphasise that linear and circular polarisation vision are not different modalities--both are necessary for optimal polarisation vision, regardless of the presence of strongly linear or circularly polarised features in the animal's environment.Comment: 10 pages, 6 figures, 2 table

On the Series of +CG Lightning Strokes in Dancing Sprite Events

In dancing sprite events, sprite entities and groups appear in rapid succession together with a corresponding series of parent lightning strokes. Dancing sprite events, including a case with possible sprite rebrightening, were recorded on video simultaneously from two observation sites above a mesoscale convective system in Central Europe on the night of 6 August 2013. Joint analysis of triangulated locations of sprite elements, position, type, and peak current of lightning strokes from the LINET lightning detection network database and current moment waveforms deduced at the Hylaty station, Poland, showed that subsequent sprite‐parent lightning strokes occurred no further than 21 km from the closest preceding sprite entity in the cases analyzed in this study. Additionally, it was found that longer sprite delay times tend to correspond to larger sprite location offsets from the parent +CG stroke. These observations, the occurrence of +CG lightning stroke and sprite sequences, as well as sprite‐sprite delay times and displacements can be explained if +CG strokes are part of one extended lightning flash. A corresponding production mechanism based on previous findings on the formation of sprite‐producing and general +CG lightning discharges is suggested

Testing SNe Ia distance measurement methods with SN 2011fe

The nearby, bright, almost completely unreddened Type Ia supernova 2011fe in M101 provides a unique opportunity to test both the precision and the accuracy of the extragalactic distances derived from SNe Ia light curve fitters. We apply the current, public versions of the independent light curve fitting codes MLCS2k2 and SALT2 to compute the distance modulus of SN 2011fe from high-precision, multi-color (BVRI) light curves. The results from the two fitting codes confirm that 2011fe is a "normal" (not peculiar) and only slightly reddened SN Ia. New unreddened distance moduli are derived as 29.21 +/- 0.07 mag (D ~ 6.95 +/- 0.23$ Mpc, MLCS2k2), and 29.05 +/- 0.07 mag (6.46 +/- 0.21 Mpc, SALT2). Despite the very good fitting quality achieved with both light curve fitters, the resulting distance moduli are inconsistent by 2 sigma. Both are marginally consistent (at ~1 sigma) with the HST Key Project distance modulus for M101. The SALT2 distance is in good agreement with the recently revised Cepheid- and TRGB-distance to M101. Averaging all SN- and Cepheid-based estimates, the absolute distance to M101 is ~6.6 +/- 0.5 Mpc.Comment: 8 pages, 7 figures, accepted for publication in A&

Impact of month of birth on the development of autoimmune thyroid disease in the United Kingdom and Europe

CONTEXT: Viral/bacterial infection is proposed as a trigger for the autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto's thyroiditis (HT). Previous studies in European Caucasian AITD subjects found higher birth rates in the autumn/winter, suggesting those born in the autumn/winter experience increased viral/bacterial exposure after birth, impacting upon immune system development and predisposing to AITD later in life. OBJECTIVE: Month of birth effects were investigated in three independent European Caucasian AITD datasets. DESIGN: Variation in GD and HT onset was compared across months and seasons, with fluctuations across all 12 months analyzed using a Walter-Elwood test. SETTING: The study was conducted at a research laboratory. PATIENTS: National UK Caucasian AITD Case Control Collection (2746 GD and 502 HT compared with 1 423 716 UK births), National UK Caucasian GD Family Collection (239 GD and 227 unaffected siblings), and OXAGEN AITD Caucasian Family Collection (885 GD, 717 HT, and 794 unaffected siblings of European Caucasian decent). MAIN OUTCOME MEASURES: Case-control and family-based association studies were measured. RESULTS: No consistent month of birth effects were detected in GD females or males across all three collections. In HT females from the OXAGEN AITD Caucasian Family Collection, slightly higher birth rates were detected in autumn (Walter's test statistic = 7.47, P = .024) however, this was not seen in the HT females from the case-control cohort. CONCLUSION: Our results suggest in UK/Northern European Caucasian GD subjects, month of birth does not impact on AITD development. Although some month of birth effects for HT females in one collection cannot be excluded, only further work in larger European Caucasian AITD collections can confirm these effects

Automated Model Merge by Design Space Exploration

Industrial applications of model-driven engineering to develop large and complex systems resulted in an increasing demand for collaboration features. However, use cases such as model differencing and merging have turned out to be a difficult challenge, due to (i) the graph-like nature of models, and (ii) the complexity of certain operations (e.g. hierarchy refactoring) that are common today. In the paper, we present a novel search-based automated model merge approach where rule-based design space exploration is used to search the space of solution candidates that represent conflict-free merged models. Our method also allows engineers to easily incorporate domain-specific knowledge into the merge process to provide better solutions. The merge process automatically calculates multiple merge candidates to be presented to domain experts for final selection. Furthermore, we propose to adopt a generic synthetic benchmark to carry out an initial scalability assessment for model merge with large models and large change sets