An introduction to how chi-square and classical exact tests often wildly misreport significance and how the remedy lies in computers

Goodness-of-fit tests based on the Euclidean distance often outperform chi-square and other classical tests (including the standard exact tests) by at least an order of magnitude when the model being tested for goodness-of-fit is a discrete probability distribution that is not close to uniform. The present article discusses numerous examples of this. Goodness-of-fit tests based on the Euclidean metric are now practical and convenient: although the actual values taken by the Euclidean distance and similar goodness-of-fit statistics are seldom humanly interpretable, black-box computer programs can rapidly calculate their precise significance.Comment: 41 pages, 25 figures, 7 tables. arXiv admin note: near complete text overlap with arXiv:1108.412

The response of hot wires in high Reynolds-number turbulent pipe flow

Issues concerning the accuracy of hot-wire measurements in turbulent pipe flow are addressed for pipe Reynolds numbers up to 6 × 106 and hot-wire Reynolds numbers up to Rew ap 250. These include the optimization of spatial and temporal resolution and the associated feature of signal-to-noise ratio. Very high wire Reynolds numbers enable the use of wires with reduced length-to-diameter ratios compared to those typical of atmospheric conditions owing to increased wire Nusselt numbers. Simulation of the steady-state heat balance for the wire and the unetched portion of wire are used to assess static end-conduction effects: they are used to calculate wire Biot numbers, \sqrt{c_0}l , and fractional end-conduction losses, σ, which confirm the 'conduction-only' theory described by Corrsin. They show that, at Rew ap 250, the wire length-to-diameter ratio can be reduced to about 50, while keeping \sqrt{c_0}l\gt3 and σ < 7% in common with accepted limits at Rew ap 3. It is shown that these limits depend additionally on the choice of wire material and the length of unetched wire. The dynamic effects of end-cooling are also assessed using the conduction-only theory

Riccati Solutions of Discrete Painlev\'e Equations with Weyl Group Symmetry of Type E8(1)E_8^{(1)}

We present a special solutions of the discrete Painlev\'e equations associated with $A_0^{(1)}$, $A_0^{(1)*}$ and $A_0^{(1)**}$-surface. These solutions can be expressed by solutions of linear difference equations. Here the $A_0^{(1)}$-surface discrete Painlev\'e equation is the most generic difference equation, as all discrete Painlev\'e equations can be obtained by its degeneration limit. These special solutions exist when the parameters of the discrete Painlev\'e equation satisfy a particular constraint. We consider that these special functions belong to the hypergeometric family although they seems to go beyond the known discrete and $q$-discrete hypergeometric functions. We also discuss the degeneration scheme of these solutions.Comment: 22 page

بررسی میزان شیوع افسردگی در تازه دانشجویان رشته داروسازی زنجان بر حسب متغیرهای جمعیت شناختی

زمینه و هدف: افسردگی یک بیماری روانی شایع در دانشجویان است که دارای علائمی نظیر کاهش سطح خلق وخو، عدم وجود علایق ولذت ها در زندگی و افزایش احساس خستگی می باشد. علاوه براین افسردگی می تواند شامل زمینه و هدف: افسردگی یک بیماری روانی شایع در دانشجویان است که دارای علائمی نظیر کاهش سطح خلق وخو، عدم وجود علایق ولذت ها در زندگی و افزایش احساس خستگی می باشد. علاوه براین افسردگی می تواند شامل علائم و اختلالات دیگر و در شرایط بدتر باعث بروز رفتارهای پرخطر نظیر اعتیاد به الکل وداروها وحتی خودکشی گردد. پژوهش حاضر با هدف مطالعه شیوع افسردگی دانشجویان بر حسب متغیرهای جمعیت شناختی بر روی دانشجویان انجام شد. روش بررسی: در یک مطالعه توصیفی- مقطعی در سال 1392، با استفاده از روش نمونه گیری در دسترس 83 دانشجوی رشته داروسازی در دانشگاه علوم پزشکی زنجان انتخاب شدند.. داده های مربوط به شیوع افسردگی دانشجویان (تعیین شده بوسیله پرسشنامه بک) و اطلاعات جمعیت شناختی جمع آوری و بوسیله نرم افزار Spss18 تحلیل شدند. یافته ها: نتایج پژوهش نشان داد که میزان شیوع کلی افسردگی در دانشجویان مورد مطالعه 4/9 درصد می باشد. نتایج همچنین نشان داد بین شیوع افسردگی دانشجویان بومی و غیربومی تفاوت معناداری وجود دارد(01/0p<). اما بین شیوع افسردگی در دانشجویان دختر و پسر تفاوت معناداری مشاهده نشد. همچنین بین معدل تحصیلی و میزان افسردگی رابطه معناداری وجود نداشت. نتیجه گیری: نتایج پژوهش شواهدی را پیشنهاد می کند که دور از خانواده زندگی کردن می تواند در بروز شیوع افسردگی دانشجویان نقش داشته باشد. لذا به منظور کاهش بروز شیوع افسردگی در دانشجویان پیشنهاد می شود برنامه های آموزشی ارتقاء سلامت روان و توانمندسازی روانی از یک سو و بومی گزینی از سوی دیگر مد نظر قرار گیرد

Approaches to the Monopole-Dynamic Dipole Vacuum Solution Concerning the Structure of its Ernst's Potential on the Symmetry Axis

The FHP algorithm allows to obtain the relativistic multipole moments of a vacuum stationary axisymmetric solution in terms of coefficients which appear in the expansion of its Ernst's potential on the symmetry axis. First of all, we will use this result in order to determine, at a certain approximation degree, the Ernst's potential on the symmetry axis of the metric whose only multipole moments are mass and angular momentum. By using Sibgatullin's method we analyse a series of exacts solutions with the afore mentioned multipole characteristic. Besides, we present an approximate solution whose Ernst's potential is introduced as a power series of a dimensionless parameter. The calculation of its multipole moments allows us to understand the existing differences between both approximations to the proposed pure multipole solution.Comment: 24 pages, plain TeX. To be published in General Relativity and Gravitatio

Entangling capabilities of Symmetric two qubit gates

Our work addresses the problem of generating maximally entangled two spin-1/2 (qubit) symmetric states using NMR, NQR, Lipkin-Meshkov-Glick Hamiltonians. Time evolution of such Hamiltonians provides various logic gates which can be used for quantum processing tasks. Pairs of spin-1/2's have modeled a wide range of problems in physics. Here we are interested in two spin-1/2 symmetric states which belong to a subspace spanned by the angular momentum basis {|j = 1, {\mu}>; {\mu} = +1, 0,-1}. Our technique relies on the decomposition of a Hamiltonian in terms of SU(3) generators. In this context, we define a set of linearly independent, traceless, Hermitian operators which provides an alternate set of SU(n) generators. These matrices are constructed out of angular momentum operators Jx,Jy,Jz. We construct and study the properties of perfect entanglers acting on a symmetric subspace i.e., spin-1 operators that can generate maximally entangled states from some suitably chosen initial separable states in terms of their entangling power.Comment: 12 page

Diagonal and transition magnetic moments of negative parity heavy baryons in QCD sum rules

Diagonal and transition magnetic moments of the negative parity, spin-1/2 heavy baryons are studied in framework of the light cone QCD sum rules. By constructing the sum rules for different Lorentz structures, the unwanted contributions coming from negative (positive) to positive (negative) parity transitions are removed. It is obtained that the magnetic moments of all baryons, except $\Lambda_b^0$, $\Sigma_c^+$ and $\Xi_c^{\prime +}$, are quite large. It is also found that the transition magnetic moments between neutral negative parity heavy $\Xi_Q^{\prime 0}$ and $\Xi_Q^0$ baryons are very small. Magnetic moments of the $\Sigma_Q \to \Lambda_Q$ and $\Xi_Q^{\prime \pm} \to \Xi_Q^\pm$ transitions are quite large and can be measured in further experiments.Comment: 31 pages, 4 figures, LaTeX formatted. arXiv admin note: substantial text overlap with arXiv:1504.00172, arXiv:1504.0818