Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural instability of the bifurcation diagram for two-dimensional flow in a channel with a sudden expansion

Flow in a symmetric channel with a sudden expansion makes a transition from a symmetric flow to an asymmetric one due to a symmetry-breaking pitchfork bifurcation on a gradual increase of the Reynolds number if the system is perfectly symmetric. However, an unavoidable infinitesimal imperfection of the system may render the pitchfork bifurcation imperfect. A weakly nonlinear stability analysis is proposed to investigate the structural instability of the bifurcation for such a flow. As a result, an amplitude equation for a disturbance is derived by including the effect of the imperfection of the system, and its coefficients are evaluated numerically. The equilibrium amplitude of the disturbance is calculated from the amplitude equation and compared with the experimental results for the flow in a channel that is presumed symmetric and also with the numerical solution of the full nonlinear equations for the flow in a slightly asymmetric channel.
Implied-Meaning Analysis of the Currian Conditional

Expanding on the recent research of Stephen Read and Catarina Dutilh Novaes concerning Thomas Bradwardine's theory of truth, the present paper makes an effort to analyse the Currian conditional in terms of the so-called ‘Bradwardine principle’, i.e. the principle that meaning is closed under entailment. Based upon two possible applications of this approach, alternative solutions to the issues of semantic pathology and trivialisation of deductive systems are presented.
DIRECTIONAL ALIGNMENT AND NON-GAUSSIAN STATISTICS IN SOLAR WIND TURBULENCE

The magnetic and velocity field fluctuations in magnetohydrodynamic turbulence can be characterized by their directional alignment and induced electric field. These manifest as coherent spatial correlations which are measures of Alfvénicity and turbulence cascade strength, respectively. Solar wind observations and direct numerical simulations find that these distinctive correlations, caused by rapid relaxation processes that act to suppress nonlinearity, occur in localized spatial patches. This cellularization of magnetofluid turbulence is inconsistent with a superposition of Gaussian fields and could be related to spatial intermittency or other non-Gaussian statistics.
Evolution of low-mass stars in the alpha Persei cluster.

We present a photometric and spectroscopic study of low-mass members of the . cap alpha. Persei cluster. Now relative proper motions have been obtained for 4000 stars in a 1X2 x 1X2 region of the . cap alpha. Persei open cluster. The survey extends to Vroughly-equal16.5 mag, much fainter than the previous proper motion surveys. Optical photometry and high-dispersion spectroscopy of the possible cluster members from our survey, as well as a set of 10th to 12th magnitude stars from previous surveys, have also been obtained. The new photometry shows an apparent pre-main sequence (PMS), but we cannot yet accurately determine the PMS turn-on point. The faint stars in the cluster have positions in a V versus V-I diagram that are roughly in accord with the 5 x 10/sup 7/ yr isochrone derived by VandenBerg et al. In agreement with previous results for the Pleiades cluster, some of the late-type . cap alpha. Persei members are photometric variables, with periods of 1 day or less. Light curves and estimated periods are presented for six of the G and K dwarf members of the cluster. We attribute the periodic light variations to spots on the surfaces of these stars, which are carried around themore » visible hemisphere by rapid rotation. The photometric periods are consistent with rotational broadening measurements when available. Projected rotational velocities derived from the echelle spectra indicate that nearly 50% of the stars observed that are later than G2 have 25 km s/sup -1/« less
Effect of image processing version on detection of non-calcification cancers in 2D digital mammography imaging

Image processing (IP) is the last step in the digital mammography imaging chain before interpretation by a radiologist. Each manufacturer has their own IP algorithm(s) and the appearance of an image after IP can vary greatly depending upon the algorithm and version used. It is unclear whether these differences can affect cancer detection. This work investigates the effect of IP on the detection of non-calcification cancers by expert observers. Digital mammography images for 190 patients were collected from two screening sites using Hologic amorphous selenium detectors. Eighty of these cases contained non-calcification cancers. The images were processed using three versions of IP from Hologic – default (full enhancement), low contrast (intermediate enhancement) and pseudo screen-film (no enhancement). Seven experienced observers inspected the images and marked the location of regions suspected to be non-calcification cancers assigning a score for likelihood of malignancy. This data was analysed using JAFROC analysis. The observers also scored the clinical interpretation of the entire case using the BSBR classification scale. This was analysed using ROC analysis. The breast density in the region surrounding each cancer and the number of times each cancer was detected were calculated. IP did not have a significant effect on the radiologists’ judgment of the likelihood of malignancy of individual lesions or their clinical interpretation of the entire case. No correlation was found between number of times each cancer was detected and the density of breast tissue surrounding that cancer.
Random correction for positron emission tomography using singles count rates

To obtain quantitative images in PET (Positron Emission Tomography) the correction for randomly occurring coincidences is an important step prior to reconstruction. Especially in 3D mode, random coincidences contribute considerably to all measured events. Tomographs with more open geometries and extended field of view (FOV) are particularly prone to random coincidences. Therefore efforts are made to develop methods for an estimation of their contributions as exact as possible and subtract them from the measured signal. A new random correction method has been developed and investigated. The estimation of random coincidences was done by using singles count rates of detector ensembles. This approach does not need a separate random measurement in a delayed coincidence window (standard technique) and thus it should relieve the load on the coincidence controller. More true coincidences could be recorded this way. The inferior statistical quality of the random measurements compared to the singles measurements is a further stimulus to utilize singles for the estimation. The performance of the new method has been compared with the current standard technique and its benefits have been quantified in a range of imaging situations. It has been demonstrated that the use of the new algorithm should lead to significant gains in performance.
Eikonal calculations of short‐wavelength internal‐wave spectra

Following Henyey and Pomphrey (1983), we investigate the spectrum of small-scale internal waves using the eikonal method. We send test-wave packets through background internal-wave shear fields, varying the initial distributions and the background spectra. We find that the test-wave distributions evolve to Garrett-Munk wave number spectra for all the cases investigated. We find that the test waves evolve toward higher frequencies, in contrast to a simple induced diffusion model, and consistent with a picture of low-frequency internal-wave sources.
Forecasting Tornadic Thunderstorm Potential in Alberta Using Environmental Sounding Data. Part II: Helicity, Precipitable Water, and Storm Convergence

Abstract Sounding parameters are examined to determine whether they can help distinguish between Alberta, Canada, severe thunderstorms that spawn significant tornadoes (F2–F4), weak tornadoes (F0–F1), or nontornadic severe storms producing large hail. Parameters investigated included storm-relative helicity (SRH), precipitable water (PW), and storm convergence. The motivation for analyzing these parameters is that, in theory, they might affect the rate of change of vertical vorticity generation through vortex stretching, vortex tilting, and baroclinic effects. Precipitable water showed statistically significant differences between significant tornadic storms and those severe storms that produced weak tornadoes or no tornadoes. All significant tornadic cases in the dataset used had PW values exceeding 22 mm, with a median value of 24 mm. Values of PW between 19 and 23 mm were generally associated with weak tornadic storms. Computed values of storm convergence, height of the lifted condensation level, and n.
Social Cohesion in Postcolonial Singapore: Effects of Anti-Immigrant Attitudes and Authoritarianism

The paper presents an examination of the predictors of social cohesion in Singapore based on an analysis of the impact of anti-immigrant attitudes and authoritarianism on the nation’s state-led social togetherness. The binary logistic regression models find that hostility to immigration and trust in state institutions reduces social cohesion, while authoritarian attitudes promote it. The results of the analysis indicate that state support measures for social cohesion in a postcolonial society appear ambivalent. It is striking that the predictors of social cohesion developed predominantly in Western contexts show no or a different kind of influence in Singapore than in Western societies. Consequently, multicultural Singaporean society obviously also reacts to cohesion policies with a stronger differentiation into separate groups. These policies should therefore focus even more strongly than before on societal cohesion.
Theoretical and practical aspects of selected fiber‐blend color‐formulation functions

Color matching blends of precolored fiber using three different methods was studied. Best color-matching accuracy was obtained using a two-constant Kubelka-Munk (KM) procedure. First-formula color differences averaged 1.6 CIELAB units and were found to be within the experimental error of 1.6 CIELAB units. Useful approximations were obtained using the methods proposed by Friele and by Stearns. First-formula color matches averaged 2.4 CIELAB units for the Stearns and 2.7 CIELAB units for the Friele methods. The methods are mathematically compared and the merits of each are discussed. Where possible, interpretation of the empirical parameters each method employs is attempted. It is pointed out that absorption and scattering constants calculated for fibers using the KM formalism are not true KM absorption and scattering constants. It is demonstrated that too literal an interpretation of these constants leads to apparent anomalies. It is shown that the fiber KM scattering constants which are normally considered unchanged as dye is applied cannot be considered unchanged if these same fibers are subsequently to be used in blends with other colored fibers.
Coronal Plasma Motions near Footpoints of Active Region Loops Revealed from Spectroscopic Observations with Hinode EIS

The solar active region 10938 has been observed from the disk center to the west limb with the Hinode EUV Imaging Spectrometer. In the disk-center observation, subsonic upflow motions of tens of km s−1 and enhanced nonthermal velocities have been found near the footpoints of the active region loops assuming a single Gaussian approximation for the emission-line profiles. When the same part of the active region is observed near the limb, both upflows and enhanced nonthermal velocities essentially decrease. There is a strong correlation between Doppler velocity and nonthermal velocity. Significant deviations from a single Gaussian profile are found in the blue wing of the line profiles for the upflows. These suggest that there are unresolved high-speed upflows. We discuss the implications for coronal heating mechanisms.
A Studentized Permutation Test for the Comparison of Spatial Point Patterns

In this study, a new test is proposed for the hypothesis that two (or more) observed point patterns are realizations of the same spatial point process model. To this end, the point patterns are divided into disjoint quadrats, on each of which an estimate of Ripley’s K-function is calculated. The two groups of empirical K-functions are compared by a permutation test using a Studentized test statistic. The proposed test performs convincingly in terms of empirical level and power in a simulation study, even for point patterns where the K-function estimates on neighboring subsamples are not strictly exchangeable. It also shows improved behavior compared with a test suggested by Diggle et al. for the comparison of groups of independently replicated point patterns. In an application to two point patterns from pathology that represent capillary positions in sections of healthy and cancerous tissue, our Studentized permutation test indicates statistical significance, although the patterns cannot be clearly distinguished by the eye.
A BAYESIAN APPROACH EMPLOYING GENERALIZED DIRICHLET PRIORS IN PREDICTING MICROCHIP YIELDS

ABSTRACT In the production model studied by Jewell and Chou, since some of the sorting probabilities for different categories of microelectronic chips tend to be positively correlated, a Dirichlet distribution is an inappropriate prior for that model. Jewell and Chou therefore propose an approximation approach to predict coproduct yields. Since a generalized Dirichlet distribution allows variables to be positively correlated, a Bayesian method by assuming generalized Dirichlet priors is presented to calculate the probabilities of future yields in this paper. We consider not only the mean values, but also either the variances or the covariances of the sorting probabilities to construct generalized Dirichlet priors. The numerical results indicate that the generalized Dirichlet distribution should be a reasonable prior, and the computation in forecasting coproduct output is relatively straightforward with respect to the approximation approach.
X-Ray/Optical Studies of Two Outbursts of the Intermediate Polar YY (DO) Draconis

YY Draconis (likely the same variable called DO Draconis) is one of a small number of intermediate polars (IPs) that show outburst behavior. We report results from Target of Opportunity observations with the Rossi X-Ray Timing Explorer, together with ground-based optical photometry during outbursts in 1999 September and 2000 November. Similar behavior was evident in both outbursts. At outburst, the X-ray flux increased by more than a factor of 12, and the spectrum became hotter and more absorbed compared to quiescence. While the spin pulse at 529 s is clearly present in the X-ray data at 2–4 days past outburst peak and during quiescence, it was not detected in the X-ray data closest to outburst (1.5 days). This is contrary to the large increase in spin pulse amplitude that has been seen during outbursts of the IPs GK Per, XY Ari, and EX Hya. The differences in YY Dra are likely due to its unique geometry, with two relatively equal poles located near the white dwarf equator. The equal enhancement of both poles near outburst could account for the low pulse amplitude, while unequal feeding of the poles as the magnetosphere recedes during decline could explain the changes in amplitude and pulse shape. The changing height of the shocks may also have an effect on the visibility of both poles.
The effect of grain and particle size on the microwave properties of barium titanate (BaTiO3)

The use of ferroelectric ceramics and thin films in microwave devices requires that they possess frequency-stable, low-loss dielectric properties. At microwave frequencies, ferroelectric polycrystalline ceramic materials typically exhibit a large dielectric relaxation, characterized by a decrease in the relative permittivity (er) and a peak in the dielectric loss (tan δ). Mechanisms attributed to the relaxation phenomenon include piezoelectric resonance of grains and domains, inertia to domain wall movement, and the emission of gigahertz shear waves from ferroelastic domain walls. As a result, the relaxation phenomenon appears to be intimately linked to the domain state of the ferroelectric. The domain state of a ferroelectric is, in part, dependent upon its microstructure. In this study, the microwave dielectric properties of ferroelectric barium titanate were measured as a function of grain and particle size. Polycrystalline ceramic ferroelectric BaTiO3 (having average grain sizes of 14.4, 2.14, and 0.2.
Gender assessment of arable crop farmers in soil management practices in Osun State, Nigeria.

The study assessed the roles of arable crop farmers in soil management practices on gender basis. Specifically, it identified the common soil management practices used among arable crop farmers and assessed the level of involvement of men and women arable crop farmers in soil management practices. A multi- stage sampling procedure was used for sample selection. Data collected were described using descriptive statistics such as mean, standard deviation, frequency and percentages, appropiate charts and analysed using correlation and t-test. The findings revealed that the mean age of the male farmers was 46.3±9.51 years while that of the female respondents was 38.7±7.91 years. Application of inorganic fertilizer was the dominant soil management practice used by both male and female farmers with male involving more in all the soil management practices. Results of correlation analysis showed that there were positive and significant relationship between men and women arable crop farmers' level of involvement in soil management practices and age (r=0.997), years of formal education (r=0.640), number of children assisting in farming (r=0.694), sources of credits (r=0.921) at P≥0.05 level of significance. Also, income per year (r=-0.661), was negative but significant at 0.05 level of significant. Also, t-test results showed that significant differences exist between male and female arable crop farmers in soil management practices in the study area at P≥0.01. The study therefore, concludes that male were more involved in all the soil management practices identified in the study area. It was therefore recommended that gender policies that could bridge the gaps between male and female arable crop farmers in soil management practices should be put in place by the government with a view to increasing soil fertility, hence increased food production in Osun State.
Comparing Demographic Characteristics of Male Victims of Domestic Violence

The present study investigated the demographic characteristics of male victims of domestic violence. These demographic characteristics were menxs age, level of education and level of income. To do this, an author-made questionnaire regarding victimization of domestic violence, both, physical and psychological, was administered to 120 randomly chosen men, referred to family courts by their councilors to seek divorce because of experiencing domestic violence. The results showed that age had significant effect on physical violence; specifically, hitting and psychological violence; specifically, denying choices and cessation of intermarital intercourse. Also, the level of education had significant effect on the physical (e.g., throwing objects) and psychological (e.g., Cessation of marital intercourse and denying choices). Finally, present results indicated that the level of income, by itself, did not have any effects on experiencing any types of violence by men but its effect was visible and significant in the presence of the other two factors, the age and the level of education. The results in the present study are, in fact, only of their kinds in that the characteristics of abused men by their wives are assessed in male victims of domestic violence and can contribute to further understanding of the types of men susceptible to victimization by their wives. Furthermore, it should be pointed out that other demographic variables such as the number of children, the type of housing (ownership of the house or renting) and so on, were also determined in this study, but given their lack of any significant effects on the occurrence of violence of any kind against men, were not mentioned in the study.
An IRT-Based Two-Wave Model for Studying Short-Term Stability in Personality Measurement

This article describes an item response theorybased structural equation model that allows the short-term stability and the magnitude of retest effects to be assessed for some types of personality traits. The relations between the model estimates and the usual procedures for assessing invariance in IRT are described. An empirical application of the model is given, the substantive implications of the results are discussed, and suggestions for further research and methodological procedures are presented.
Jeans collapse of turbulent gas clouds: tentative theory

The linear Jeans stability problem in a turbulent medium is treated using a description of the large-scale motions, with the response of turbulence on the small scales being treated using a renormalization approach. This treatment shows how turbulence at scales smaller than the potentially collapsing scale builds up a turbulent pressure force which effectively resists compression, if the kinetic energy is sufficient to balance the gravitational attraction.
Numerical Study of an Oscillating Airfoil in Transonic Buffeting Flows

Numerical simulations are conducted to compute the aerodynamic flowfield response that is observed for a NACA0012 airfoil that undergoes prescribed harmonic oscillation at transonic Mach numbers. Large shock oscillations are observed for certain combinations of Mach number and steady mean angle of attack. These are termed as buffet in this paper. Prescribing an airfoil oscillation about the buffeting flowfield reveals a nonlinear interaction between the flowfields induced by the buffet and airfoil motion, respectively. At low airfoil-oscillation amplitudes, the time histories of the aerodynamic coefficients exhibit two frequencies, that of the buffet and that of the oscillating airfoil. As the airfoil amplitude increases, the flowfield response at the buffet frequency decreases. Beyond a certain level of airfoil amplitude, lock-in occurs: the flowfield response at the buffet frequency vanishes, and the flow system response predominantly assumes the frequency of the airfoil motion. The airfoil amplitude that will cause lock-in is dependent on the ratio between the frequency of the airfoil oscillation and the buffet frequency. The closer these frequencies are, the smaller the airfoil-oscillation amplitude that will cause lock-in. There is a broad analogy between this flow phenomenon and the flowfield of the von Karman vortex street found behind a cylinder with the cylinder undergoing a prescribed oscillation. This paper reviews that phenomenon, suggests an aerodynamic gain-phase model for the lock-in region, and suggests a possible relation between this flow mechanism and limit-cycle oscillation.
Symbiotic stars in the Magellanic Clouds.

Searches of UK Schmidt Telescope objective prism plates have revealed four new symbiotic stars in the Magellanic Clouds. These include the first M-type donor identified in the Magellanic Clouds and two more carbon star donors. The relatively high proportion of carbon star donors is maintained. Details of the spectral characteristics and variability of these stars are presented
Some problems of analytic number theory

This is in continuation of the paper with the same title but with number IV. Theorem 6 of that paper reads as follows. Let 00 exp(((s)) 00 = :~::)nn-• and expexp(((s)) =L dnn-• n=l n=l in R( s) > 1. Then we have and '°' dn = ~ f L. ,, n~x 27rt expexp(((s)) x• ds 8 circle + O(x 1 -•) for every fixed c > 0 (throughout this paper circle means the curve Is - ll = -fo, s # -fa, traversed in the anticlockwise direction) as x --+ oo. In the present paper we prove that these results are valid even when ((s) is replaced by o(((s)) 13 where a and (3 are any non- zero complex constants.