Asymmetry Of Curves Research Articles

A non-volatile four-state magnetic memory in a Co/(011)Pb(Mg1/3Nb2/3)O3-PbTiO3 heterostructure

A non-volatile four-state magnetic memory is achieved in a Co/(011)Pb(Mg1/3Nb2/3)O3-PbTiO3 heterostructure. The in-plane magnetization of ferromagnetic Co film in the heterostructure can be controlled both electrically and magnetically. Electric field mediated magnetism is caused by piezostrain effect, which displays a stable non-volatile remnant magnetization vs electric field looplike behavior. In-plane strain-electric field (S-E) behavior under different temperatures reveals a non-volatile strain switching effect, which is responsible for the non-volatile remnant magnetization switching through piezostrain mediated magnetoelectric effect. Further investigations on temperature dependence of S-E behavior suggest that the absent of the second non-180° domain switching may be responsible for the asymmetry in strain curves that causes the non-volatile strain switching, and therefore causes the non-volatile remanent magnetization switching, which is crucial for the four-state magnetoelectric memory.

Coronal Spinal Balance in Adult Spine Deformity Patients With Long Spinal Fusions

This study was a retrospective one. The objective of the study was to analyze the causes, prevalence of, and risk factors for coronal decompensation in long adult lumbar spinal instrumentation and fusion (from thoracic or upper lumbar spine) to L5 or S1. Coronal and sagittal decompensation after long fusions for spinal deformities can affect outcomes negatively. There is no study reporting the natural history of coronal spinal balance after long spinal fusions. A single-center retrospective review of data from 54 patients with spinal deformity was performed. Inclusion criteria were patients over 18 years with long fusions (>4 segments) to L5 or the pelvis who had full spine standing radiographs before surgery and up to 2-5 years postoperatively. Radiographic data included C7PL, magnitude of scoliotic curve, shoulder or pelvic asymmetry in the coronal plane, thoracic kyphosis, lumbar lordosis, and pelvic parameters (pelvic incidence, pelvic tilt, sacral slope). Coronal imbalance (CI) was considered if the C7PL was >4 cm lateral to the central sacral line, and sagittal imbalance (SI) was considered when the C7 plumbline was >4 cm anterior to the middle of the upper sacral plate. Paired t test, χ test, and repeated measures regression analysis using demographic data (age, sex, body mass index), operative (previous fusion, posterior only or anteroposterior fusion, iliac fixation or not, decompression or not, osteotomy or not) and postoperative (complications, use of bracing) data, and radiographic parameters (including SI) were performed. Patients showing CI equaled 11 (19.3%) preoperatively, remained 11 (19.3%) (4 of whom were new patients with CI) at 6 weeks postoperatively, and increased (P<0.001) to 18 (31.6%) (8 of them without initial CI) at 2-5 years follow-up. However, in terms of numeric distance of C7PL from the midsacrum, there was no statistically significant change (P>0.05) from preoperative to last follow-up. SI showed significant improvement (P<0.05) from preoperative to 6 weeks postoperative and no statistical significant change (P>0.05) from 6 weeks to 2-5 years postoperatively. Repeated measures regression analysis showed that the presence of osteoporosis and the combination of anterior approach surgery with a history of previous surgery were significant (P<0.05) factors predictive of changes in coronal balance. After surgical correction of spinal deformities, coronal spinal decompensation appears in an increased number of patients at last follow-up postoperatively but without significant differences in coronal plane C7PL during the postoperative period. Attention should be paid to patients with osteoporosis and those with a combination of previous same site posterior spine surgery and new anterior approach surgery for changes of coronal balance postoperatively.

In response: some species sensitivity distribution statistics revisited--a governmental perspective.

In response: some species sensitivity distribution statistics revisited--a governmental perspective.

Orbital Solutions and Absolute Elements of the W UMa Binary MW Pavonis

We present differential UBV photoelectric photometry obtained by Williamon of the short-period A-type W UMa binary MW Pav. With the Wilson–Devinney analysis program, we obtained a simultaneous solution of these observations with the UBV photometry of Lapasset, the V measurements by the ASAS program, and the double-lined radial velocity measurements of Rucinski and Duerbeck. Our solution indicates that MW Pav is in an overcontact state, where both components exceed their critical Roche lobes. We derive masses of M 1 = 1.514 ± 0.063 M ⊙ and M 2 = 0.327 ± 0.014 M ⊙, and equal-volume radii of R 1 = 2.412 ± 0.034 R ⊙ and R 2 = 1.277 ± 0.019 R ⊙ for the primary and secondary, respectively. The system is assumed to have a circular orbit and is seen at an inclination of 86.39° ± 0.63°. The effective temperature of the primary was held fixed at 6900 K, whereas the secondary’s temperature was found to be 6969 ± 10 K. The asymmetry of the light curves requires a large, single star spot on the smaller, less massive secondary component. A consistent base solution, with different spot characteristics for the Williamon, Lapasset, and ASAS data, was found. The modeled spot varied little during the 40-year range of photometric observations. The combined solution utilized a third light component and found that the period is changing at a rate of dP/dt = (6.50 ± 0.19) × 10-10.

FIRST PHOTOMETRIC INVESTIGATION OF THE SOLAR-TYPE CONTACT BINARY GSC 1537–1557

By analyzing R-c and I-c light curves of the short-period solar-type eclipsing binary GSC 1537-1557 we discovered that it is a shallow contact binary with a degree of contact factor of f = (8.10 +/- 1.79)%. Photometric solutions reveal that GSC 1537-1557 is a W-type system with a mass ratio of q = M-2/M-1 = 2.645 where the less massive component (the primary star) is about 110 K hotter than the more massive one (the secondary star). The asymmetry and variation of the light curves were explained as the activity of spots on the solar-type component stars. By investigating all of the available times of light minima, we found that the observed-calculated (O-C) curve shows a cyclic variation with a small amplitude of 0.00335 days and a period of 8.1 years. The small-amplitude cyclic change in the O - C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion. The mass of the third body was determined to be M-3 sin i' =(0.19 +/- 0.01) M-circle dot when M-1 + M-2 = 1.31 M-circle dot is adopted for GSC 1537-1557. The semimajor axis of the outer obit is a' sin i' =(4.58 +/- 0.33) AU.

Exchange bias effect modulated anisotropic magnetoresistance in Fe/YMnO3 multiferroic bilayers

The effects of the interfacial coupling on the magnetic and magnetotransport properties of Fe/YMnO3 multiferroic bilayers were investigated through the dependence of exchange bias effect on the ferromagnetic layer thickness and temperature. A transition of anisotropic magnetoresistance (AMR) behaviors from a heart-shape-like to a sin2(φa) dependence was acquired by mediating the competition between external magnetic field and exchange bias field. Furthermore, the exchange bias field produces a torque with opposite effect during the clockwise and anticlockwise rotation process of the external magnetic field, which leads to a phase shift and asymmetry of AMR curves. Our work shows an effective way of controlling the magnetotransport properties by interfacial coupling effect in ferromagnet/multiferroic systems.

FIRST PRECISION LIGHT CURVE ANALYSIS OF THE NEGLECTED EXTREME MASS RATIO SOLAR-TYPE BINARY HR BOOTIS

HR Bootis is a neglected binary that is found to be a solar-type (G2V) extreme mass ratio binary (EMRB). It was discovered by Hanley & Shapley in 1940. Surprisingly, little has been published in the intervening years. In 1999 it was characterized by a 0.31587 day orbital period. Since that time it has been observed by various observers who have determined ?20 timings of minimum light over the past ?15,000 orbits. Our observations in 2012 represent the first precision curves in the BVRcIc Johnson?Cousins wavelength bands. The light curves have rather low amplitudes, averaging some 0.5 magnitudes, yet they exhibit total eclipses, which is typical of the rare group of solar-type EMRBs. An improved linear ephemeris was computed along with a quadratic ephemeris showing a decaying orbit, which indicates magnetic breaking may be occurring. The light curve solution reveals that HR Boo is a contact system with a somewhat low 21% Roche-lobe fill-out but a mass ratio of q = 4.09 (0.2444), which defines it as an EMRB. Two spots, both hot, were allowed to iterate to fit the light curve asymmetries. Their radii are 32? and 16?. Both are high-latitude polar spots indicative of strong magnetic activity. The shallow contact yet nearly equal component temperatures makes it an unusual addition to this group.

Latitudinal distribution of soft X-ray flares and dispairty in butterfly diagram

We present statistical analysis of about 63000 soft X-ray flare (class≥C) observed by geostationary operational environmental satellite (GOES) during the period 1976–2008. Class wise occurrence of soft X-ray (SXR) flare is in declining trend since cycle 21. The distribution pattern of cycle 21 shows the transit of hemispheric dominance of flare activity from northern to southern hemisphere and remains there during cycle 22 and 23. During the three cycles, 0–100, 21–300 latitude belts in southern hemisphere (SH) and 31–400 latitude belt in northern hemisphere (NH) are mightier. The 11–200 latitude belt of both hemisphere is mightiest. Correlation coefficient between consecutive latitude appears to be increasing from equator to poleward in northern hemisphere whereas pole to equatorward in southern hemisphere. Slope of the regression line fitted with asymmetry time series of daily flare counts is negative in all three cycles for different classes of flares. The yearly asymmetry curve fitted by a sinusoidal function varies from 5.6 to 11 years period and depends upon the intensity of flare. Variation, of curve fitted with wings of butterfly diagram, from first to second order polynomial suggests that latitudinal migration of flare activity varies from cycle to cycle, northern to southern hemisphere. The variation in slope of the butterfly wing of different flare class indicates the non uniform migration of flare activity.

Fundamental parameters of the close interacting binary HD 170582 and its luminous accretion disc

We present a spectroscopic and photometric study of the Double Period Variable HD170582. Based on the study of the ASAS V-band light curve we determine an improved orbital period of 16.87177 $\pm$ 0.02084 days and a long period of 587 days. We disentangled the light curve into an orbital part, determining ephemerides and revealing orbital ellipsoidal variability with unequal maxima, and a long cycle, showing quasi-sinusoidal changes with amplitude $\Delta V$= 0.1 mag. Assuming synchronous rotation for the cool stellar component and semi-detached configuration we find a cool evolved star of $M_{2}$ = 1.9 $\pm$ 0.1 $M_{\odot}$, $T_{2}$ = 8000 $\pm$ 100 $K$ and $R_{2}$ = 15.6 $\pm$ 0.2 $R_{\odot}$, and an early B-type dwarf of $M_{1}$ = 9.0 $\pm$ 0.2 $M_{\odot}$. The B-type star is surrounded by a geometrically and optically thick accretion disc of radial extension 20.8 $\pm$ 0.3 $R_{\odot}$ contributing about 35% to the system luminosity at the $V$ band. Two extended regions located at opposite sides of the disc rim, and hotter than the disc by 67% and 46%, fit the light curve asymmetries. The system is seen under inclination 67.4 $\pm$ 0.4 degree and it is found at a distance of 238 $\pm$ 10 pc. Specially interesting is the double line nature of HeI 5875; two absorption components move in anti-phase during the orbital cycle; they can be associated with the shock regions revealed by the photometry. The radial velocity of one of the HeI 5875 components closely follows the donor radial velocity, suggesting that the line is formed in a wind emerging near the stream-disc interacting region.

Analysis on the absorption curve asymmetry of electromagnetically induced transparency in Rb87 cold atoms

The asymmetry of the absorption curve of electromagnetically induced transparency by a resonant coupling field in -type three-level systems for Rb87 cold atoms is investigated. We find that it is the other excited state, separated by an interval of 814 MHz, that induces this phenomenon. The primary cause of it is the stimulated Raman scattering. We also find that the ratio between the heights of the absorption peaks on the two sides of the transparency window is proportional to the intensity of the coupling beam. The theoretical result agrees well with the experimental data.

STELLAR KINEMATICS AND STRUCTURAL PROPERTIES OF VIRGO CLUSTER DWARF EARLY-TYPE GALAXIES FROM THE SMAKCED PROJECT. II. THE SURVEY AND A SYSTEMATIC ANALYSIS OF KINEMATIC ANOMALIES AND ASYMMETRIES

We present spatially resolved kinematics and global stellar populations and mass-to-light ratios for a sample of 39 dwarf early-type (dE) galaxies in the Virgo cluster studied as part of the SMAKCED stellar absorption-line spectroscopy and imaging survey. This sample is representative of the early-type population in the absolute magnitude range -19.0 < M_r < -16.0. For each dE, we measure the rotation curve and velocity dispersion profile and fit an analytic function to the rotation curve. We study the significance of the departure of the rotation curve from the best fit analytic function (poorly fit) and of the difference between the approaching and receding sides of the rotation curve (asymmetry). We find that 62 +/- 8 % (23 out of the 39) of the dEs have a significant anomaly in their rotation curve. Analysis of the images reveals photometric anomalies for most galaxies. However, there is no clear correlation between the significance of the photometric and kinematic anomalies. We measure age-sensitive and metallicity-sensitive Lick spectral indices and find a wide range of ages and metallicities. We also find that 4 dEs have emission partially filling in the Balmer absorption lines. Finally, we estimate the total masses and dark matter fractions of the dEs. They have a median total mass and dark matter fraction within the Re of log Me = 9.1 +/- 0.2 and f_DM = 46 +/- 18 %. We plot several scaling relations and show that dEs seem to be the bridge between massive early-type and dwarf spheroidal galaxies.

Magnetization Measurements and XMCD Studies on Ion Irradiated Iron Oxide and Core-Shell Iron/Iron-Oxide Nanomaterials

Magnetite (Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) and core-shell iron/iron-oxide (Fe/FexOy) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions and the structures determined by X-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, X-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack a strong signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite, so it is likely that most FeO (octahedral Fe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ) exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> sample are due to interfaces and interactions between grains, which were not present in samples before irradiation, as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.

Modelling and forecasting the trends of life cycle curves in the production of non-renewable resources

In this study, we review mathematical models of trends in the production of non-renewable resources. We propose new models that allow specifying curve asymmetry and use genetic algorithms as curve-fitting methods. We estimate the quality of fit of our proposed models and use them to predict oil production in the OECD (Organisation for Economic Co-operation and Development) countries, the EU, the U.S., Norway, Syria, the UK, and some fields in Russia; gas production in the EU, the UK and Italy; shale gas production in the U.S.; coal production in the U.S. and Germany; as well as global gold production. The models fit the data accurately in all these cases.

A study of as-grown, poled and reduced Rh-doped KNbO3 single crystals by high-resolution X-ray diffraction, Raman scattering, photoluminescence and dielectric measurements

As-grown and chemically reduced Rh-doped (1500 p.p.m.) KnbO3 single crystals grown by the Czochralski method have been characterized. Reduction of the grown crystals at different levels was carried out under a mixture of CO and CO2 gases as the crystals were grown with excess oxygen. The effect of reduction and poling on crystalline perfection was studied by high-resolution X-ray diffraction (HRXRD) using a multi-crystal X-ray diffractometer developed in-house. The diffraction curves of the as-grown, electrically poled, moderately reduced and heavily reduced single-crystal specimens show remarkable differences. The studies by HRXRD reveal that poling has some influence on the improvement of crystalline perfection, while chemical reduction has a great influence on crystalline perfection; at moderate reduction the crystal becomes nearly perfect, but when the reduction is very heavy the crystal quality decreases slightly, although it is still better than for unreduced samples. Asymmetry of the diffraction curves with respect to the peak position reveals that the as-grown specimens contain a high concentration of both vacancies and self-interstitials. After poling, the concentration of self-interstitial defects is lowered to some extent. When the specimen is moderately chemically reduced, the scattered intensity on both sides of the peak is greatly reduced, showing that the concentrations of both vacancies and interstitials are reduced to a great extent owing to chemical reduction. This clearly indicates that, as a result of the chemical reduction of oxygen in the crystal, crystalline perfection is enhanced significantly. However, under heavy chemical reduction, the number of vacancy defects is increased to a significant extent. Raman scattering, dielectric and photoluminescence studies also show interesting features, with excellent correlation with the degree of crystalline perfection influenced by the processes of reduction and poling.

CCD photometric study of a contact binary HH Ursae Majoris

New complete BV light curves of a poorly investigated contact binary HH Ursae Majoris (HH UMa) are presented. The light curves are analyzed by using the 2003 version of the Wilson–Devinney (W–D) code. Combining with the radial velocity published by the previous investigators, we obtain the photometric solution of the system. The solution indicates that HH UMa is a W-type W UMa system with a mass ratio of q=m2/m1=3.344 and a contact degree of 31.9%. The system has a very low inclination of i=53.035° and a temperature difference of 247K between two components. The asymmetry of the light curves can be explained by adding a hot spot located near the neck region of the more massive component. A period investigation based on all available data shows that the period increases at a rate of dP/dt=2.84×10-7daysyr−1, which can be explained by mass transfer from the less massive component to the more massive one. We also give the absolute parameters of the system.

Orbital Solutions and Absolute Elements of the Short-Period Eclipsing Binary ES Librae

We have obtained new differential UBV photoelectric photometry and radial velocities of both components of the short-period eclipsing binary ES Lib. The system has a circular orbit with a period of 0.883040928 days and is seen at an inclination of 70.1°. With the Wilson-Devinney analysis program, we obtained a simultaneous solution of our photometric and spectroscopic observations that resulted in masses of M1 = 2.30 ± 0.03 M⊙ and M2 = 0.97 ± 0.01 M⊙ and the equal-volume radii of R1 = 2.69 ± 0.02 R⊙ and R2 = 1.83 ± 0.01 R⊙ for the primary and secondary, respectively. The secondary is oversized and overluminous for its mass. The effective temperatures of the primary and secondary are 8500 K (fixed) and 5774 ± 57 K, respectively. Despite the very large temperature difference, our photometric and spectroscopic data indicate that ES Lib is not semidetached but rather require it to be in an overcontact state, where both components exceed their critical Roche lobes. Given its nonthermal equilibrium state, if the overcontact solution correctly characterizes the system, the change from being semidetached to overcontact may have occurred recently. While the asymmetry of the light curves can be modeled well with a large, hot starspot or a large, cool one on the secondary component, we prefer the latter interpretation because cool spots are a typical feature on many contact binaries.

Measurement and analysis of the air pressure curve on the rigid lenses by use of ocular response analyzer.

Pressure curves obtained from Ocular Response Analyzer (ORA) differ for the same patient in form and height. In some cases measurements on the subject show significant differences between recorded pressure curves. The purpose of the paper is to examine if the differences result from the corneal properties or from the device operation. Examination of air pressure curves was carried out on four plano-convex glass lenses with radii of curvature close to the central corneal radius. Lenses were mounted in front of the air jet of the ORA analyzer. Series of 30 measurements on each lenses were recorded with 20 s and 60 s time interval between measurements. RESULTS were exported to computer and analyzed numerically. RESULTS show much higher reproducibility of pressure curves in every series of measurements in comparison to pressure curves recorded on the patients eye. This demonstrates that ORA produces air pulses with high reproducibility. Differences in air pressure pulses for the real eye can indicate the dynamics of ocular properties during measurements. Obtained pressure curves are not symmetrical and not well fitted by Gaussian curve. Type of asymmetry of air pressure curves may be explained by viscoelasticity of air.

The First Comprehensive Photometric Study of the Neglected Binary System V345 Cassiopeiae

We present the first BVRI CCD photometric observations of V345 Cas made on 22 nights during the observing seasons in 2007-2008. Our light curves, resembling those of EB-type binary stars, are analyzed with the 2003 version of the WilsonDevinney binary code. The photometric study shows that V345 Cas is a typical semi-detached binary system with the primary star being about ΔT = 2400 K hotter, two times more massive, but only 17% larger than the secondary star being filled with it's Roche-lobe. The orbit has a relatively large inclination of about 88°. A cool spot on the secondary component is modeled to explain a small light curve asymmetry. Absolute dimensions and related radiometric parameters of the eclipsing pair are calculated and their evolutionary states are discussed with the HR diagrams of mass-radius and temperature-luminosity. A period analysis of all available times of minima, including our measurements, indicates that the orbital period may vary in a cyclical way, unfortunately the secondary period for the variation can not be uniquely determined because of lack of present timing data.

First photometric study of totally eclipsing detached binary V667 Lyr

The first BVR photometry and light curve modeling of totally eclipsing detached binary V667 Lyr are presented. Eclipse timings obtained in this study were used to determined accurate light elements of the system. Eclipse depth of light curves indicates ∼1500K temperature difference while relatively long total eclipse shows large radius difference between components. Advantage of total eclipse allowed to estimate mass ratio of the system via well known mass–luminosity relation as q=0.54. Analysis showed that the secondary component has sub-solar mass, which brings to mind chromospheric activity possibility. However, no remarkable asymmetries in light and color curves were observed in the first observations. By using photometric properties, mass ratio and period of the system, masses and radii of the primary and secondary components were estimated as M1=1.55M⊙, M2=0.84M⊙ and R1=1.98R⊙, R2=0.95R⊙, respectively. Estimated physical properties of the primary component put the system on a distance of 680pc.

A HIGHLY INCLINED ORBIT FOR THE 110 DAY PERIOD M-DWARF COMPANION KOI-368.01

We report the detection of asymmetry in the transit light curves of the 110-day period companion to KOI-368, a rapidly rotating A-dwarf. The significant distortion in the transit light curve is attributed to spin-orbit misalignment between the transiting companion and the gravity darkened host star. Our analysis was based on 11 Long Cadence and 2 Short Cadence transits of KOI-368.01 from the Kepler mission, as well as stellar parameters determined from our follow-up spectroscopic observation. We measured the true obliquity between the orbit normal and the stellar rotation axis to be 69 +9/-10 deg. We also find a secondary eclipse event with depth 29 +/- 3 ppm at phase 0.59, from which the temperature of the companion is constrained to 3060 +/- 50 K, indicating that KOI-368.01 is a late M-dwarf. The eccentricity is also calculated from the eclipse to be 0.1429 +/- 0.0007. The long period, high obliquity, and low eccentricity of KOI-368.01 allow us to limit a number of proposed theories for the misalignment of binary systems.