Multiple small angle neutron scattering in ferromagnets

The conclusions arising from the multiple small angle neutron scattering theory, developed recently by S.V. Maleyev, R.V. Pomortsev and Y.N. Skryabin [Phys. Rev. B 50 7133 (1994)] for the value of Born parameter more than 1, are experimentally confirmed by magnetic scattering from domain structure of pure Fe and Ni, as well as Fe_{65}Ni_{35} alloy. The crossover from multiple refraction to multiple Fraunhofer diffraction is found to be at a critical thickness L_0, where dependence of the neutron beam broadening w on sample thickness L changes from law L^{1/2} to law L.Comment: 2 pages, latex, espcrc2.sty, 2 figures; to appear in the Proceedings of the 1st European Conference on Neutron Scattering, Physica

Overview Of Nonlinear Kinetic Instabilities

The saturation of shear Alfven-like waves by alpha particles is presented from the general viewpoint of determining the saturation mechanisms of basic waves in a plasma destabilized by a perturbing source of free energy. The formalism is reviewed and then followed by analyses of isolated mode saturation far from and close to marginal stability. The effect of multiple waves that are isolated or are overlapping is then discussed. The presentation is concluded with a discussion of a non-conventional quasilinear theory that covers both extreme cases as well as the intermediate regime between the extremes.Physic

The Concept of Neighbourhood in Contemporary Residential Environments: An Investigation of Occupants' Perception

The dwelling occupant satisfaction is related to the efficiency of the combination of numerous factors stemming from the qualitative and quantitative aspects of the various components of the residential environment. Those components exist at a whole scale ranging from an interior space within the housing unit to the whole urban environment. This study aimed to explore the immediate social and physical environment around the dwelling unit, which is often referred to as “neighbourhood”. In addition to the physical space that the concept reminds, the term neighbourhood is also used to describe a socially distinguished area depending on residents’ perception. In the traditional sense, this physical space is outlined with virtual boundaries that are traced differently in the minds of each individual according to the life style and type of social interaction and the type of use of the physical environment. The perceptions of residents’ in relation with this neighbourhood area are also affected with both physical and social characteristics of the concerned environment. This paper aimed to investigate the situation of the neighbourhood concept in contemporary urban residential environments by making use of the data obtained from two distinct independent housing researches conducted in Turkey. The analysis and evaluation of the findings together with an overview of the literature reflecting the traditional and contemporary neighbourhood concepts in Turkish residential environments, reveals that changes are about to occur in the definition, creation and experiencing of the neighbourhood issue. The evaluation of the literature, manifestos and approaches of most housing institutions and policy builders in the contemporary world expose a rather increasing interest to the issue of neighbourhood as the concept constitutes an important component of residential satisfaction. The findings of this study indicate that the neighbourhood feeling in contemporary urban environments is now less dependent on the sharing of common close physical residential environment due to housing initiatives driven by liberal / random land use options, financial viability and profitability. The benefits expected of the use of the close physical environment is disregarded due to possibilities obtained with increasing mobility and transportation facilities. The remote activities and life styles of dwelling occupants become the basic factors that shape the social environment. The segregation of the close social environment from the close physical environment is a major source for residential environment dissatisfaction. A conclusion drawn from the findings is that the physical properties of the close built environment may act as sources of dissatisfaction if the residents’ perception of neighbourhood notion is disregarded during residential environment design. Hints to increase dwelling occupants’ satisfaction from the residential environment lies in redefining the neighbourhood concept through creating adequate, functioning, distinct, value added common spaces that ease admittance and social interaction. However, those spaces shall be a part of the urban tissue. The long-term effects of physical segregation, clustering of the residential environments, creating of sprawl type settlements shall be re-evaluated

Measuring Solvency In The Turkish Public Transportation Industry Cem

Financial analysis is a combined effort of knowledge and experience to obtain relevant ratios and elaborate on the results. The study is an application of financial analysis on Istanbul Public Transportation Company. As seen in the literature review section of the study public transportation companies require high subsidies by governments which is a factor to consider in the research. The research period is 2014- 2016. It is a comparative study with the inclusion of Izmir – ESHOT and Ankara – EGO public transportation companies. The results are therefore compared with industry averages computed by the average of public transportation companies of three big cities in Turkey. The research is based on 7 selected ratios, 3 for measuring liquidity and the remaining 4 for measuring solvency. The ratios used in this paper are current ratio, acid test ratio, cash ratio, total debt ratio, debt equity ratio, equity multiplier, and long term debt ratio. According to the results, the companies have a very low current ratio which means they operate with low liquidity. Solvency analysis also reveal that, there are high degrees of leverage and negative shareholders’ equity. The research shows that companies might struggle to repay debts without government support

Supersparse Linear Integer Models for Optimized Medical Scoring Systems

Scoring systems are linear classification models that only require users to add, subtract and multiply a few small numbers in order to make a prediction. These models are in widespread use by the medical community, but are difficult to learn from data because they need to be accurate and sparse, have coprime integer coefficients, and satisfy multiple operational constraints. We present a new method for creating data-driven scoring systems called a Supersparse Linear Integer Model (SLIM). SLIM scoring systems are built by solving an integer program that directly encodes measures of accuracy (the 0-1 loss) and sparsity (the $\ell_0$-seminorm) while restricting coefficients to coprime integers. SLIM can seamlessly incorporate a wide range of operational constraints related to accuracy and sparsity, and can produce highly tailored models without parameter tuning. We provide bounds on the testing and training accuracy of SLIM scoring systems, and present a new data reduction technique that can improve scalability by eliminating a portion of the training data beforehand. Our paper includes results from a collaboration with the Massachusetts General Hospital Sleep Laboratory, where SLIM was used to create a highly tailored scoring system for sleep apnea screeningComment: This version reflects our findings on SLIM as of January 2016 (arXiv:1306.5860 and arXiv:1405.4047 are out-of-date). The final published version of this articled is available at http://www.springerlink.co

Small area estimation of the homeless in Los Angeles: An application of cost-sensitive stochastic gradient boosting

In many metropolitan areas efforts are made to count the homeless to ensure proper provision of social services. Some areas are very large, which makes spatial sampling a viable alternative to an enumeration of the entire terrain. Counts are observed in sampled regions but must be imputed in unvisited areas. Along with the imputation process, the costs of underestimating and overestimating may be different. For example, if precise estimation in areas with large homeless c ounts is critical, then underestimation should be penalized more than overestimation in the loss function. We analyze data from the 2004--2005 Los Angeles County homeless study using an augmentation of $L_1$ stochastic gradient boosting that can weight overestimates and underestimates asymmetrically. We discuss our choice to utilize stochastic gradient boosting over other function estimation procedures. In-sample fitted and out-of-sample imputed values, as well as relationships between the response and predictors, are analyzed for various cost functions. Practical usage and policy implications of these results are discussed briefly.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS328 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org