Equal Zero Research Articles

Minimal Spaces with Cyclic Group of Homeomorphisms

There are two main subjects in this paper. (1) For a topological dynamical system (X,T) we study the topological entropy of its “functional envelopes” (the action of T by left composition on the space of all continuous self-maps or on the space of all self-homeomorphisms of X). In particular we prove that for zero-dimensional spaces X both entropies are infinite except when T is equicontinuous (then both equal zero). (2) We call Slovak space any compact metric space whose homeomorphism group is cyclic and generated by a minimal homeomorphism. Using Slovak spaces we provide examples of (minimal) systems (X,T) with positive entropy, yet, whose functional envelope on homeomorphisms has entropy zero (answering a question posed by Kolyada and Semikina). Finally, also using Slovak spaces, we resolve a long standing open problem whether the circle is a unique non-degenerate continuum admitting minimal continuous transformations but only invertible: No, some Slovak spaces are such, as well.

多重散射效应对部分相干源两粒子关联函数的影响

The normal method handling the HBT rescattering effect is classical random cascade of secondary collision in high energy heavy ion collisions program whose goal is to seek the quark-gluon plasma. Interferometry, also called Hanbury-Brown Twiss (HBT) effects, is an important tool to study the space-time feature of particle-emitting source, and is an effective method to examine the quantum chromodynamics phase transition. As the HBT interference phenomenon of two identical particles is quantum mechanical in nature, and HBT results are affected by the particle-emitting source collective expansion, excited-particle decays and rescattering of particles in the source, hence, these effects should be studied properly in quantum mechanics frame. In this thesis, based on Glaubers scattering model, we use the method of path integral to analysis the rescattering effect on two-particle correlation functions of the partially coherent sources and give the formulas of two-particle correlation functions adding a absorbing factor due to rescattering effect by studying the quantum transport of the interfering identity particle pair, which include the rescattering effect. The two-particle correlation functions of the partially coherent sources contain a phase which is sensitive to the asymmetry of the source emission function and the rescattering effect shift the phase from zero and cause asymmetry of particle emission source. We investigate the influence of rescattering in high energy heavy ion collision on two-particle correlation functions for the partially coherent sources by Monte Carlo calculations. The result shows that the rescattering effect makes the phase not equal zero, causing asymmetry of particle emission source. The rescattering effect makes particles hard to emit from the center of sources, particles tend to emit from the surface of sources and the emitting time shorten. The Gaussian-formula fit results to the simulated two-particle correlation functions indicate that rescattering effect leads to a smaller interferometry radius due a shorter emitting time.

Hydrocarbon potential, thermal maturation of the Jurassic sequences, and the genetic implication for the oil seeps in North Thrust Zone, North Iraq

The organic geochemistry is studied for the rocks of three Jurassic formations: Sargelu, Naokelekan, and Chia Gara from the north of Iraq. These rocks comprise bituminous carbonate and shale rocks. The hydrocarbon source rock potential is evaluated by using total organic carbon (TOC) and Rock-Eval Pyrolysis. The prevalence of high values of TOC (2.21–45.12 wt.%) associated with moderate to high values of HI (225–550 mg HC/g TOC), low OI (1–33 CO2/g TOC), and high S2 values (4.53–181.0) indicate very good to excellent source rock potential for these rocks with mostly type II kerogen and few mixed-type II/III kerogen of oil prone source rocks. This is supported by high values of S2/S3 ratios (>5). Tmax values range from 440 to 447 °C in agreement with the calculated R o values (0.76–0.90) infer early to peak thermally mature stage. Based on the TOC and pyrolysis data, the rocks of the three formations have indigenous hydrocarbon mature oil prone. The geochemical investigation of biomarker parameters were performed for oil samples from two oil seepages (Banik and Tawke) which are located in the same area using gas chromatography-mass spectrometry and stable carbon isotope measurements. The measured values of Pr/n-C17 for oil samples are low coupled with high values of Ph/n-C18 indicating marine organic matters with type II kerogen accumulated under marine reducing condition. The values and plots of δ13C (saturate and aromatic) also approve the prevalence of marine reducing condition. The source rocks for the oils of both seepages are interpreted to be carbonate rocks of Mesozoic age by the measured CV values which are 0.25. All these data are in consistent with marine carbonate source rocks for these oils. The paleoredox depositional environment for the source rocks is interpreted by the low value of Pr/Ph (0.74 in Banik) and high values of homohopane ratio C35S/C34S (1.21 in Banik and 1.13 in Tawke); the values of C29/C30 (norhopane/hopane >1) as well as the high sulfur content all indicate reducing condition during the deposition of the marine source rocks. The concentrations of C27, C28, and C29 reflect the prevalence of marine algal plankton organic matters. The measured Oleanane index equal zero which indicates age older than Lower Cretaceous for the source rocks. This documented by the calculated values of C28/C29 sterane ratio, and plots on Geomark Research database gives an age of Middle–Upper Jurassic for the source rocks. According to the characteristics of depositional environment of the source rocks, the paleoredox condition, and age estimation, the oils of Banik and Tawke could be derived from the rocks of Sargelu, Naokelekan, and Chia Gara Formations.

Strict Descriptions of Some Typical 2×2 Games and Negative Games

In this paper, we shall give the strict description of some typical 2×2 games such as stag hunt, game of chicken, battle of the sexes, prisoner’s dilemma (briefly PD) and Rasumsen’s boxed pigs and we shall invent three new game stories, game of musicians, game of ruffians and negative Rasumsen boxed pigs. Every game is not necessarily symmetrical. We shall divide battle of the sexes into two forms and introduce the concept of weak PD. A game is said to be negative game of another one if the sum of their payoff functions is equal zero. The following main results will be obtained. (1) A negative game of chicken is a stage hunt. (2) A negative non-weak PD is a non-weak PD, where defection and cooperation of the original non-weak PD are corresponding to cooperation and defection of the negative non-weak PD respectively. The negative game of a weak PD is not a PD. (3) The negative first battle of the sexes is the game of musicians and the negative second one is the game of ruffians. (4) The negative Rasmusen boxed pigs is a weak PD and so is asymmetrical. (5) The guilt game as a negative Rasmusen boxed pigs is not a non-weak PD; it is a weak PD if and only if the small pig is conscienceless.

Motifs des variétés analytiques rigides

In this work, I extend the theory of motives, as developed by Voevodsky and Morel-Voevodsky, to the context of rigid analytic geometry over a complete non archimedean field. The first chapter deals with the homotopical approach of Morel and Voevodsky. One finds there the construction of the motivic stable homotopy category of rigid analytic varieties and a complete description of this category in terms of algebraic motives when the base field has equal characteristic zero and its valuation is discrete. The second chapter deals with Voevodsky's approach based on transfers. One finds there the construction of the triangulated category of rigid analytic motives, and an extension to rigid analytic geometry of a large number of Voevodsky's fundamental results such as his theory of homotopy invariants presheaves with transfers. This is said, the present work is a lot more than just a mere copy of the classical theory and the reader will find a lot of results that are new and specific to rigid analytic geometry.

Uniform central limit theorems for the Grenander estimator

We consider the Grenander estimator that is the maximum likelihood estimator for non-increasing densities. We prove uniform central limit theorems for certain subclasses of bounded variation functions and for Hölder balls of smoothness $s>1/2$. We do not assume that the density is differentiable or continuous. The proof can be seen as an adaptation of the method for the parametric maximum likelihood estimator to the nonparametric setting. Since nonparametric maximum likelihood estimators lie on the boundary, the derivative of the likelihood cannot be expected to equal zero as in the parametric case. Nevertheless, our proofs rely on the fact that the derivative of the likelihood can be shown to be small at the maximum likelihood estimator.

What Determines the Firm’s Net Trade Credit? Evidence from Macedonian Listed Firms

This paper analyzes the net trade credit and its determinants for a sample of 23 non-financial firms for the year 2011. The sample is derived from Macedonian Stock Exchange. The net trade credit is the dependent variable. Dependent variable is defined as the difference between trade receivables and liabilities, and then this difference is divided by total assets. Maturity structure of assets, size, profitability, inventory investment, and cash to assets ratio, long-term financing, total debt financing, and converting sales into cash are the independent variables. Both types of variables, dependent and independent are quantitative variables. Both are expressed on their book values. Variables are transformed and necessary post-selection adjustments will be done. Data and results are checked using Shapiro-Wilk W test for normality, Kernel density estimation, Cameron & Trivedi’s decomposition of IM-test and Breusch-Pagan / Cook-Weisberg test for heteroscedasticity, Variance Inflation Factor for multicollinearity, the model specification link test for single-equation models, and the regression specification error test for omitted variables. Relevant conclusions are drawn based on Spearman and regression analysis. Obtained results show that firms with more net trade credit are more profitable. Firms with higher portion of current assets are bigger firms and invest more in inventory than counterparties. Bigger firms have more inventory than smaller firms. Firms with higher leverage ratios are less able to convert sales into cash. Net trade credit is negatively significant associated with inventory to assets ratio, leverage ratio, and net cash flows from operating activities to sales. Net trade credit is positively significant associated with current assets to total assets ratio. Profitability is found statistically significant determinant, but with beta and standard error equal zero. Results show that net trade credit ratio on average is slightly small, but positive. A positive net trade credit indicates that on average trade receivables are higher than trade payables. With other words, analyzed firms for the analyzed period have sell more than have bought on credit. Keywords: net trade credit, accounts receivable, accounts payable, financial ratios, regression.

Conditions of resonance interaction of acoustic periodic waves interaction

We consider differential equations of gas dynamics, when the thermal conductivity and viscosity coefficients equal zero. The system is supplemented with equations of state for the gas pressure and the total energy; these equations do not depend on the properties of gas, i.e. are of a general form. We construct asymptotical approximation for the resonance interaction of acoustic periodic waves, which is uniformly valid in the long time interval. A system coefficient allows determining the resonance occurring condition the relation between gas pressure and temperature at the initial time. We investigate the ideal and non-ideal gas and determine the relationship between the parameters, which causes the of resonanse vanishing in non-ideal gas.

Uso fertilizante do subproduto da agroindústria processadora de goiabas II: estado nutricional e produção de goiabas

O conhecimento sobre a dinâmica dos nutrientes provenientes da aplicação de resíduos orgânicos faz-se necessário, principalmente visando sua a reciclagem, considerando que a quantidade desses materiais tem aumentado rapidamente com o tempo. Assim, objetivou-se avaliar o estado nutricional e a produção de frutos de um pomar de goiabeiras, em função da aplicação do subproduto da indústria processadora de goiabas. O delineamento empregado foi o de blocos casualizados, com cinco tratamentos e quatro repetições, sendo as doses do subproduto (moído) iguais a zero; 9;18; 27 e 36 t ha-1 (peso do material seco). Foram feitas cinco aplicações do subproduto em 2006, 2007, 2008, 2009 e 2010. Avaliou-se o estado nutricional das goiabeiras, via diagnose foliar (macro e micronutrientes), bem como a produção de frutos por seis safras consecutivas. A aplicação do subproduto da indústria processadora de goiabas promoveu alterações no estado nutricional e na produção de frutos. As doses do subproduto incrementaram os teores foliares de N, Mg e Mn da goiabeira. A produção de goiabas cresceu de forma linear em função das doses do subproduto. Os efeitos da aplicação do subproduto foram verificados primeiramente no solo, posteriormente nos teores foliares e, finalmente, na produção de frutos, ao longo das safras.

An Analysis of the Relationship between Risk and Expected Return in the BRVM Stock Exchange: Test of the CAPM

One of the most important concepts in investment theory is the relationship between risk and return. This relationship drives the theoretical foundation of many investment models such as the well known Capital Asset Pricing Model which predicts that the expected return on an asset above the risk-free rate is linearly related to the non-diversifiable risk measured by its beta. This study examines the Capital Asset Pricing Model (CAPM) and test it validity for the WAEMU space stock market called BRVM (BOURSE REGIONALE DES VALEURS MOBILIERES) using monthly stock returns from 17 companies listed on the stock exchange for the period of January 2000 to December 2008. Combining Black, Jensen and Scholes with Fama and Macbeth methods of testing the CAPM, the whole period was divided into four sub-periods and stock’s betas used instead of portfolio’s betas due to the small size of the sample.The CAPM’s prediction for the intercept is that it should equal zero and the slope should equal the excess returns on the market portfolio. The results of the study refute the above hypothesis about the slope and offer evidence against the CAPM for all the sub-period and even for the whole period. The tests conducted to examine the nonlinearity of the relationship between return and betas support the hypothesis that the expected return-beta relationship is linear. Additionally, this paper investigates whether the CAPM adequately captures all-important determinants of returns including the residual variance of stocks.The results demonstrate that residual risk has no effect on the expected returns of stocks for the whole period and the entire sub –periods except for the last period of 2003-2008 which shows that returns are affected by non-systematic risks during that specific period, justifying the fact that the operating activities of the firms have an impact on their stocks returns

Temporal correlation of blinking events in CdSe/ZnS and Si/SiO2 nanocrystals

Well passivated single Si/SiO2 nanoparticles obey mono-exponential blinking statistics, whereas CdSe/ZnS quantum dots follow an apparent (truncated) power-law. Log-normal distributions are found to describe the interval length histograms at least as well as power-laws, while at the same time being more physically feasible and significantly easing the determination of the exponential cutoff in the ON-time distribution. The correlation of an ON- (OFF-)interval with its temporally displaced ON (OFF) neighbors, as well as that of intermixed intervals (ON with OFF and OFF with ON neighbors) has been studied. As expected from purely random processes, the correlation coefficients for events in silicon nanocrystals equal zero, whereas positive correlations between the pure and negative correlations between the mixed states in CdSe quantum dots hint at a switching process between two distinct blinking regimes that are slower than the blinking itself.

Determination of the Type of Flood-producing Thunderstorms by Some Convection-related Parameters and Radar Images in Northwestern Iran

The structure of five flood-producing storms was analyzed in northwestern Iran. The storms contained several coexisting convective cells during analysis period. We tried to obtain knowledge of Intensity, Duration and Type (IDT) of the storms by radar images and verify some convection-related parameters such as K, Showalter, Total- Total, Helicity and Energy-Helicity (EHI) indices; Convective available potential energy (CAPE) and Bulk Richardson number (BRN) in the area. The surface and upper air data were taken from General Forecast System (GFS) with spatial resolution of 0.5°×0.5° and a temporal resolution of 6 h. Results show, the CAPE values for thunderstorms are equal zero or less than 1000 Jkg-1 even for super and multi cells in the area. The most flood producing thunderstorms was single or multi cell and those merges together and makes Complex cell. One of the cases was twin squall lines that accompanied with cold front. Super-cell without Tornado sign was very infrequent. The growth of vertical cell in radar images has the direct relationships with convective available potential energy.

Dual-channel dispersionless slow light based on plasmon-induced transparency

I have proposed a dual-channel dispersionless slow-light waveguide system based on plasmon-induced transparency. By appropriately tuning the stub depth, two transparency windows in the transmission spectrum can be achieved due to the destructive interference between the electromagnetic fields from the three stubs. Two flat bands can be achieved in the transparency windows, which have nearly constant group indices over the bandwidth of 2 THz. The analytical results show that the group velocity dispersion parameters of the two channels equal zero, which indicates that the incident pulse can be slowed down without distortion. The proposed plasmonic waveguide system can realize slow-light effect without pulse distortion, and thus can find important applications on slow-light systems, optical buffers, and all-optical signal processors in highly integrated optical circuits.

An Addendum to “A New Tool for Climatic Analysis Using Köppen Climate Classification”

The Köppen climatic classification system in a modified format is the most widely applied system in use today. Mapping and analysis of hundreds of arid and semiarid climate stations has made the use of the additional fourth letter in BW/BS climates essential. The addition of “s,” “w,” or “f” to the standard three-letter designation adds significant information when mapping and analysis is being conducted. A new quantity is herein proposed, the potential excess precipitation value (PEP value). The PEP value is actual annual precipitation minus potential annual evapotranspiration. When mapped, PEP value equal zero is the boundary between BS and C or D climates.

Meta-analysis of mean differences from randomized trials with nested clustering

Nesting of patients within care providers in trials of physical and talking therapies creates an additional level within the The statistical implications of this are analogous to those of cluster-randomised trials, except that the clustering effect interacts with treatment, leading to different ICCs across treatment arms. In some cases, the clustering effect may be restricted to one or more of the arms, resulting in a nested design. The statistical model that is recommended at the trial-level includes a random effect for the care provider but allows the provider and patient level variances to differ across arms. The care provider variance is constrained to equal zero where there is no clustering in partially nested trials. Evidence suggests that, while important, such within-trial clustering effects are rarely taken into account in trials or in meta-analyses of these trials. This paper proposes summary measures and individual-patient-data (IPD) methods for meta-analysing randomized trials with nested clustering effects. It extends methods for incorporating trials with unequal variances and cluster-randomisation to allow for between-trial and between-arm heterogeneity in ICC estimates. The work is motivated by a meta-analysis of trials of counselling in primary care, where the outcome of interest is the Beck Depression Inventory and the control is no counselling. We begin by outlining the example and presenting the statistical model at the trial-level. We then extend standard summary measures and IPD approaches to meta-analysis of mean differences and illustrate the proposed methods with our example. Fixed and random effects meta-analysis models are contrasted.

Hilbert–Schmidt Hankel Operators over Complete Reinhardt Domains

Let \({\mathcal{R}}\) be an arbitrary bounded complete Reinhardt domain in \({\mathbb{C}^n}\). We show that for \({n \geq 2}\), if a Hankel operator with an anti-holomorphic symbol is Hilbert–Schmidt on the Bergman space \({A^2(\mathcal{R})}\), then it must equal zero. This fact has previously been proved only for strongly pseudoconvex domains and for a certain class of pseudoconvex domains.

Detecting Model Misspecification in Inflated Beta Regressions

Beta regression models are useful for modeling data that assume values in the standard unit interval (0, 1), such as rates and proportions. These models, however, cannot be used when the data contain observations that equal zero or one (the limits of the unit interval). Ospina and Ferrari (2012) developed the class of inflated beta regressions to handle situations in which the data contain positive mass at zero and/or one. The model is quite general and contains three submodels: for the mean, for the precision, and for the probability that the variate equals zero or one (α). In this article, we propose a misspecification test for inflated beta regressions with fixed and variable dispersion. In particular, we propose two variants of the test. In the first variant, we only add testing variables to the mean submodel. The second variant follows from adding testing variables to all submodels. We perform extensive Monte Carlo simulations in order to assess the finite-sample properties of the tests (size and power), and also to gain insight on which variables should be used as testing variable and on which asymptotic testing procedure delivers the most reliable inferences. We consider a number of different misspecifications, namely: neglected nonlinearities, omitted independent variables, incorrect link functions, neglected spatial correlation, and neglected variable dispersion. Finally, an empirical illustration is presented and discussed.

A Novel Pilot Protection for HVDC Transmission Lines Based on Model Error Function

In order to solve the problems in existing protection for high voltage direct current (HVDC) transmission lines, such as insufficient sensitivity for main protection and slow operation for backup protection, a novel pilot protection for HVDC transmission lines based on model error function is proposed in this paper. In the principle, through analyzing the fault component networks, external fault is equivalent to a capacitance model, while the internal fault is equivalent to a inductance model. Taking capacitance model as a benchmark, the model error function was defined to describe the degree of consistency between actual fault data and the benchmark. When an external fault occurs, fault data agree with the capacitance model and model error equals zero. When an internal fault occurs, fault data do not agree with the capacitance model and model error does not equal zero. According to this, a protection criterion is constructed. Theoretical analysis and simulation show that the new principle, not affected by transition resistance and line distributed capacitance current, can identify internal faults and external faults reliably and rapidly.

Structural and geometric characteristics of sets of convergence and divergence of multiple Fourier series with J k -lacunary sequence of rectangular partial sums

We study multiple trigonometric Fourier series of functions f in the classes \(L_p \left( {\mathbb{T}^N } \right)\), p > 1, which equal zero on some set \(\mathfrak{A}, \mathfrak{A} \subset \mathbb{T}^N , \mu \mathfrak{A} > 0\) (µ is the Lebesgue measure), \(\mathbb{T}^N = \left[ { - \pi ,\pi } \right]^N\), N ≥ 3. We consider the case when rectangular partial sums of the indicated Fourier series Sn(x; f) have index n = (n1, ..., nN) ∈ ℤN, in which k (k ≥ 1) components on the places {j1, ..., jk} = Jk ⊂ {1, ..., N} are elements of (single) lacunary sequences (i.e., we consider multiple Fourier series with Jk-lacunary sequence of partial sums). A correlation is found of the number k and location (the “sample” Jk) of lacunary sequences in the index n with the structural and geometric characteristics of the set \(\mathfrak{A}\), which determines possibility of convergence almost everywhere of the considered series on some subset of positive measure \(\mathfrak{A}_1\) of the set \(\mathfrak{A}\).

Stability of Equity and Debt Betas and the 2008-2009 Crisis

We study the behavior of betas going in and out of the 2008-2009 crisis for a broad range of equity and debt sectors. We find that most betas have reverted back to their precrisis levels, which demonstrates the general stability of long-run betas. One notable exception is the high-yield debt sector, which saw betas increase from 0.17 pre-crisis to 0.41 during the crisis and after. This appears to indicate that investors now demand much higher compensation for bearing the risk of below investment-grade debt. In addition, we find betas of the other debt sectors were generally negative regardless of the sample period. These results for debt betas contradict the common assumption used in estimating the cost of capital that debt betas equal zero or are positive.