Maximum Epoch Research Articles

SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion*

Abstract We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from −12 to +140 days with respect to the epoch of B-band maximum ( t B max ). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ∼2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred <22 hr before the first detection of the supernova, (ii) the rise time to peak bolometric (λ > 1800 Å) luminosity was 16.5 ± 0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ± 0.15 M ⊙ of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca ii and Si ii absorption features, and a nearly constant photospheric velocity of the Si ii λ6355 line at ∼12,000 km s − 1 that began ∼5 days before t B max . We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements.

The First Data Release from SweetSpot: 74 Supernovae in 36 Nights on WIYN+WHIRC

Abstract SweetSpot is a 3 yr National Optical Astronomy Observatory (NOAO) survey program to observe Type Ia supernovae (SNe Ia) in the smooth Hubble flow with the WIYN High-resolution Infrared Camera (WHIRC) on the WIYN 3.5 m telescope. We present data from the first half of this survey, covering the 2011B–2013B NOAO semesters and consisting of 493 calibrated images of 74 SNe Ia observed in the rest-frame near-infrared (NIR) in the range 0.02 < z < 0.09. Because many observed supernovae require host-galaxy subtraction from templates taken in later semesters, this release contains only the 186 NIR (JHK s ) data points for the 33 SNe Ia that do not require host-galaxy subtraction. The sample includes four objects with coverage beginning before the epoch of B-band maximum and 27 beginning within 20 days of B-band maximum. We also provide photometric calibration between the WIYN+WHIRC and Two Micron All-Sky Survey (2MASS) systems, along with light curves for 786 2MASS stars observed alongside the SNe Ia. This work is the first in a planned series of three SweetSpot Data Releases. Future releases will include the full set of images from all 3 yr of the survey, including host-galaxy reference images and updated data processing with host-galaxy reference subtraction. SweetSpot will provide a well-calibrated sample that will help improve our ability to standardize distance measurements to SNe Ia, examine the intrinsic optical–NIR colors of SNe Ia at different epochs, explore the nature of dust in other galaxies, and act as a stepping-stone for more distant, potentially space-based surveys.

Acceleration Profile of Elite Gaelic Football Match Play.

Ryan, M, Malone, S, and Collins, K. An acceleration profile of elite Gaelic football match play. J Strength Cond Res 32(3): 812-820, 2018-The use of global positioning system (GPS) technology in Gaelic football is the primary source of quantifying game demands. The aim of this study was to quantify the acceleration profile of elite Gaelic football. Thirty-six elite male Gaelic football players (mean ± SD, age: 24 ± 6 years; height: 180 ± 7 cm; mass: 81 ± 7 kg) across 5 playing positions took part in a multiple study (n = 154 observations). Player movement was recorded during 19 (n = 19) competitive games over 2 seasons using 4-Hz GPS (VXSport, New Zealand). The average total distance (m), high-speed running distance (m; ≥17 km·h), and very high-speed running distance (m; ≥22 km·h) were recorded. In addition, the number (n), distance (m), and the duration of accelerations were quantified. Accelerations were subdivided into 14 equal parts of 5-minute epochs (E1 = 0-5 minutes, E2 = 5-10 minutes, E3 = 10-15 minutes etc). Players performed 166 ± 41 accelerations. High-speed running distance and very high-speed running distance was 1563 ± 605 and 524 ± 190 m, respectively. The mean acceleration distance was 267 ± 45 m distributed between 12 ± 5 accelerations per 5-minute epoch. The maximum acceleration epoch classified as the greatest distance covered accelerating during a predetermined 5-minute epoch was 296 ± 134 m. The PEAK epoch resulted in a significant reduction of acceleration distance covered in the period before and in the subsequent epoch. An understanding of the acceleration profile in Gaelic football can inform the prescription of appropriate training regimen.

Hypertensive retinopathy identification through retinal fundus image using backpropagation neural network

Hypertension or high blood pressure can cause damage of blood vessels in the retina of eye called hypertensive retinopathy (HR). In the event Hypertension, it will cause swelling blood vessels and a decrese in retina performance. To detect HR in patients body, it is usually performed through physical examination of opthalmoscope which is still conducted manually by an ophthalmologist. Certainly, in such a manual manner, takes a ong time for a doctor to detetct HR on aa patient based on retina fundus iamge. To overcome ths problem, a method is needed to identify the image of retinal fundus automatically. In this research, backpropagation neural network was used as a method for retinal fundus identification. The steps performed prior to identification were pre-processing (green channel, contrast limited adapative histogram qualization (CLAHE), morphological close, background exclusion, thresholding and connected component analysis), feature extraction using zoning. The results show that the proposed method is able to identify retinal fundus with an accuracy of 95% with maximum epoch of 1500.

An improved prediction of sunspot maximum by Vondrak smoothing method

Studies of solar activity characteristics and prediction are gaining more attention. Using the 13‐month smoothed value of monthly sunspot numbers, we studied correlations between the rising rate of sunspot numbers of the first 24 months of the solar cycle (SC) and the coming cycle maximum; published forecasting results demonstrated that the maximum value was 139.2 ± 18.8 for the 23rd SC, while the observed value was 120.8 and the error was about 15.2%. The present paper introduces our improved forecasting methods. The Vondrak smoothing method is used to deal with the monthly sunspot numbers. The relationships between the rise rate of earlier months of sunspot numbers of Vondrak smoothed sequence and the coming maximum value in each SC are studied. The results show that the rising rate of sunspot numbers are highly related with the coming maximum values, and simulated prediction of maximum for 22 ∼ 24 cycles show that, using the 24‐month rise rate of three SCs, the maximum forecasting error is about 8.6%. The differences between prediction and observation of ascending time are within ±10%. The new prediction method can shift at least 6 months ahead in comparison with the common method using the 13‐month smoothed value, that is, the amplitude and epoch of solar maximum in the SC can be predicted about 2 years after the solar minimum.

Rainfall Forecasting Using Backpropagation Neural Network

Rainfall already became vital observation object because it affects society life both in rural areas or urban areas. Because parameters to predict rainfall rates is very complex, using physics based model that need many parameters is not a good choice. Using alternative approach like time-series based model is a good alternative. One of the algorithm that widely used to predict future events is Neural Network Backpropagation. On this research we will use Nguyen-Widrow method to initialize weight of Neural Network to reduce training time. The lowest MSE achieved is {0,02815;Â 0,01686; 0,01934; 0,03196} by using 50 maximum epoch and 3 neurons on hidden layer.

Modes of temperature and pressure variability in midlatitude troposphere and lower stratosphere in relation to cosmic ray variations

AbstractThe study is based on the analysis of atmospheric and space weather parameters in the midlatitude region (Iberian Peninsula) during, approximately, the epoch of the 24th solar cycle maximum. The principal component analysis was applied to sets of air temperature and geopotential height measurement at different pressure levels from a near‐ground level (930 hPa) to the stratosphere (up to 10 hPa). The analysis of extracted modes shows couplings between atmospheric and medium‐term variations (from weeks to months) of space weather parameters. The first mode of the atmospheric variability is related to the atmospheric dynamic processes that are common for the extratropical Northern Hemisphere. Extracted temperature and pressure variations are located in the upper troposphere‐lower stratosphere region and positively correlate with ozone content variations. Among space weather parameters, this atmospheric mode shows statistically significant negative correlation with the ground‐measured cosmic ray flux measured by the Castilla‐La Mancha neutron monitor (Spain) and weaker or no correlation with geomagnetic parameters.

Using multiple linear regression model to estimate thunderstorm activity

This paper is aimed to develop a numerical model with the use of a nonlinear model to estimate the thunderstorm activity. Meteorological data such as Pressure (P), Temperature (T), Relative Humidity (H), cloud (C), Precipitable Water Vapor (PWV), and precipitation on a daily basis were used in the proposed method. The model was constructed with six configurations of input and one target output. The output tested in this work is the thunderstorm event when one-year data is used. Results showed that the model works well in estimating thunderstorm activities with the maximum epoch reaching 1000 iterations and the percent error was found below 50%. The model also found that the thunderstorm activities in May and October are detected higher than the other months due to the inter-monsoon season.

The Relationship of Stratospheric QBO with the Difference of Measured and Calculated NmF2

The relationship between stratospheric QBO and the difference (ΔNmF2) between NmF2 calculated with IRI-2012 and measured from ionosondes at the Singapore and Ascension stations in the equatorial region was statistically investigated. As statistical analysis, the regression analysis was used on variables. As a result, the relationship between QBO and ΔNmF2 was higher for 24:00 LT (local time) than 12:00 LT. This relationship is positive in the solar maximum epoch for both stations. In the solar minimum epoch, it is negative at 24:00 LT for Ascension and at 12:00 LT for Singapore. Furthermore, it was seen that the relationship of the ΔNmF2 with both the easterly and westerly QBO was negative for all solar epochs and every LT, at Ascension station. This relationship was only positive for solar maximum epoch and 12:00 LT, at Singapore station.

The Orbital Ephemeris of the Classical Nova RR Pictoris: Presence of a Third Body?

The ex-nova RR Pic presents a periodic hump in its light curve which is considered to refer to its orbital period. By analyzing all available epochs of these hump maxima in the literature and then combining them with those from new light curves obtained in 2013 and 2014, we establish an unique cycle count scheme valid during the past 50 years and derive an ephemeris with the orbital period 0.145025959(15) days. The O—C diagram of this linear ephemeris reveals systematic deviations that could have different causes. One of them could be a light-travel-time effect caused by the presence of a hypothetical third body near the star/brown dwarf mass limit, with an orbital period of the order of 70 years. We also examine the difficulty of the problematic of detecting substellar or planetary companions of close red-dwarf white-dwarf binaries (including cataclysmic variables) and discuss other possible mechanisms responsible for the observed deviations in O—C. For RR Pic, we propose strategies to solve this question by new observations.

Investigation of Sunspot Area Varying with Sunspot Number

The statistical relationship between sunspot area (SA) and sunspot number (SN) is investigated through analysis of their daily observation records from May 1874 to April 2015. For a total of 1607 days, representing \(3~\%\) of the total interval considered, either SA or SN had a value of zero while the other parameter did not. These occurrences most likely reflect the report of short-lived spots by a single observatory and subsequent averaging of zero values over multiple stations. The main results obtained are as follows: i) The number of spotless days around the minimum of a solar cycle is statistically negatively correlated with the maximum strength of solar activity of that cycle. ii) The probability distribution of SA generally decreases monotonically with SA, but the distribution of SN generally increases first, then it decreases as a whole. The different probability distribution of SA and SN should strengthen their non-linear relation, and the correction factor [\(k\)] in the definition of SN may be one of the factors that cause the non-linearity. iii) The non-linear relation of SA and SN indeed exists statistically, and it is clearer during the maximum epoch of a solar cycle.

Energy Spectrum of the Recurrent Variation of Galactic Cosmic Rays During the Solar Minimum of Cycles 23/24

The Sun during the recent epoch of solar activity operated in a different way than during the last 60 years, being less active. We study temporal changes of the energy spectrum of the first three harmonics of the 27-day variation of the galactic cosmic rays (GCR) intensity during the unusual, recent solar minimum, between Solar Cycles 23 and 24 (SC 23/24) and compare with four previous minima. We show that the energy spectrum of the amplitudes of the recurrent variation of the GCR intensity is hard in the maximum epochs and is soft in the minimum epochs during Solar Cycles 20 – 24, but with peculiarities during the Solar Minimum 23/24. In particular, while the energy/rigidity spectrum of the amplitudes of the first harmonic of the recurrent variation of the GCR intensity behaves practically the same as for previous epochs, the energy/rigidity spectrum of the amplitudes of the second and the third harmonics demonstrates a pronounced softening. We attribute this phenomenon to the decrease of the extension of the heliosphere caused by the decrease of the solar-wind dynamic pressure during the unusual Solar Minimum 23/24.

GEOMORPHOLOGY OF THE SMERDYACH’E LAKE AND ITS SURROUNDING ROLL STRUCTURE

Geologic-geomorphologic analysis of roll surrounding Smerdyach’e Lake basin and its neighborhoods were analyzed. Lots of researchers considered this basin as a footprint of meteor impact, but there is no incontestable proof of its impact origin. The result of meteor impact is almost general lacks of stratification in roll sediments, while stratification is well-defined abroad the roll on the vast postglacial terrace. Non-rounded debris of bedding rocks to a depth of non-less than 20 m was observed in upper roll horizons. They are almost absent outside the roll. Hill-and-ridged relief adjoining from the North-East side to the roll probably is a result of oblique impact of meteor (from the South-East to the North-West) whereby mass ejection is concentrated toward moving the impactor, although probably these forms are the result of eolian factor. Upper horizons of the Polya River terrace, as in the case of one of the roll test pit, penetrates alluvium involved in cryoturbation caused by cold snap during last glacial maximum and initiate to deposit before the epoch of last glacial maximum (23–20 thousand years ago). Layers intimately associated with meteor impact cover this alluvium, and this support the idea of meteor impact in the end of cold snap epoch or soon after it, i.e. to the period from 20 to 10 thousand years ago.

Characterisation of the turbulent electromotive force and its magnetically-mediated quenching in a global EULAG-MHD simulation of solar convection

We perform a mean-field analysis of the EULAG-MHD millenium simulation of global magnetohydrodynamical convection presented in Passos and Charbonneau (2014). The turbulent electromotive force (emf) operating in the simulation is assumed to be linearly related to the cyclic axisymmetric mean magnetic field and its first spatial derivatives. At every grid point in the simulation’s meridional plane, this assumed relationship involves 27 independent tensorial coefficients. Expanding on Racine et al. (2011), we extract these coefficients from the simulation data through a least-squares minimization procedure based on singular value decomposition. The reconstructed α-tensor shows good agreement with that obtained by Racine et al. (2011), who did not include derivatives of the mean-field in their fit, as well as with the α-tensor extracted by Augustson et al. (2015) from a distinct ASH MHD simulation. The isotropic part of the turbulent magnetic diffusivity tensor β is positive definite and reaches values of 5.0×107m2s−1 in the middle of the convecting fluid layers. The spatial variations of both αϕϕ and βϕϕ component are well reproduced by expressions obtained under the Second Order Correlation Approximation, with a good matching of amplitude requiring a turbulent correlation time about five times smaller than the estimated turnover time of the small-scale turbulent flow. By segmenting the simulation data into epochs of magnetic cycle minima and maxima, we also measure α- and β-quenching. We find the magnetic quenching of the α-effect to be driven primarily by a reduction of the small-scale flow’s kinetic helicity, with variations of the current helicity playing a lesser role in most locations in the simulation domain. Our measurements of turbulent diffusivity quenching are restricted to the βϕϕ component, but indicate a weaker quenching, by a factor of ≃1.36, than of the α-effect, which in our simulation drops by a factor of three between the minimum and maximum phases of the magnetic cycle.

Tilt Angles of Solar Filaments over the Period of 1919 – 2014

The spatial and temporal distributions of solar filaments were analyzed using data from the Meudon Observatory for the period 1919-2003 and the Kislovodsk Mountain Astronomical Station for the period 1979-2014. We scanned $H_\alpha$ solar synoptic charts on which the filaments were isolated and digitized. The data on each filament comprise its location, length, area, and other geometrical characteristics. The temporal distributions of the number and total length of the filaments have been obtained. We also found latitudinal migration of filament locations with the solar cycle, and analyzed the longitudinal distribution and asymmetry of filaments in the northern and southern hemispheres, and other properties of their distribution. The tilt angles of filaments with respect the solar equator ($\tau$) were analyzed. On average, the eastern tips of filaments are closer to the poles than the western ones ($\tau \sim 10^\circ$). On the other hand, the filaments in the polar regions ($\theta>50^\circ$, where $\theta$ is the latitude) usually have negative tilts ($\tau <0^\circ$). The tilt angles vary with the phases of the 11 year sunspot cycle and are at their highest values in the epoch of the activity maximum. In the century-long modulation of the solar activity (Gleissberg cycle), the mean tilt angles of filaments in the mid-latitude zone ($\theta \sim \pm 40^\circ$) were maximum in the middle of the 20th century in solar sunspot cycles 18-19. We hereby propose using the statistical properties of solar filaments as an additional coherent measure of manifestation of the solar cycle which covers all latitudes and for which almost a century long systematically calibrated data series is available.

Pulsed nature of solar cycle 24

Solar cycle 24 is characterized by relatively weak sunspot activity and is developing according to the smallest cycle scenario (Svalgaard, Cliver, and Kamide, 2005). Using the Solar Dynamics Observatory (SDO) data for May 2010–September 2014, we present the results of a study of solar cycle 24 in the photosphere and corona during the ascending and maximum epochs. These data have been prepared in the form of synoptic maps (one map corresponds to one solar rotation) as functions of latitude and longitude for Carrington rotations CR2097–CR2154. To study the axisymmetric structure of the cycle, the maps have been averaged over longitude. Solar activity pulses, which are visible in an axisymmetric midlatitude magnetic flux, correspond to coronal brightening events in the extreme ultraviolet in the 193 A band. Solar cycle 24 is characterized by weak magnetic polar activity, weakly pronounced high-latitude waves of coronal activity, and north–south asymmetry in the sign change of the polar solar magnetic field, which is directly connected with the asymmetry in an emerging magnetic flux in the region of sunspot activity and, hence, solar activity pulses. Thus, the north polar field became mainly positive in the latitude zone from 75.01° to 79.73° in 2013, while the south field started changing sign in September 2014.

PERANCANGAN DAN IMPLEMENTASI JARINGAN SARAF TIRUAN BACKPROPAGATION UNTUK MENDIAGNOSA PENYAKIT KULIT

Skin has a great risk to be suffering from disease. Skin disease is easy to see by the other people, which could urge patient to look for health services and medications immediately. However, most people are less conscious about their skin diseases because many new skin disease which not familiar for patient, so that the skin disease can’t be handle and become worse. Information technology could solve those problems by capturing data and deliver optimal output using particular processes. This research aims to overcome the problem by developing a web based information system that implements backpropagation neural network. The symptoms of skin diseases are used as inputs and the match skin disease as output. The architecture of backpropagation neural network in this researchhas four input neurons on input layer, a hidden layer with adjustable amount of neurons and an output neuron on output layer. As a result the most optimal recognition value with validity percentage of 100% on data training and 40% on data testing with training time in 6 hours and 10 minutes using 100000 maximum epoch, 0.0001 minimum error, 0.4 learning rate and 20 neurons in hidden layer.

H2O maser flares in the source W75 N

We present the results of our study of the H2O maser emission in the intricate complex of active star formationW75 N.Our observations have been carried out at the 22-m radio telescope of the Pushchino Radio AstronomyObservatory. A possible identification of its flares with the sources VLA 1 and VLA 2 has been made. Two cycles of maser activity have been detected: 2006–2012 and 2012–2015. The main H2O maser flares occurred in VLA 1. Analysis of the evolution of the flares has shown that the flare emission is associated with a cluster of maser condensations with close radial velocities up to ~2 AU in extent. The medium in which the maser emission is generated is turbulent with various turbulence scales. Our investigation of the line shape at the epochs of flare maxima has also shown the absence of structures of the simplest form, homogeneous maser condensations. The emission in the velocity range from −10.5 to −12 km s−1 has been identified with a structure like an elongated filament with an extent of ~4 AU.

The effect of the stratospheric QBO on the neutral density of the D region

&lt;p&gt;A multiple regression model, which defines relationship between two variables, is used to perform a statistical analysis of the relationship between the stratospheric QBO and the neutral density of the D region (N&lt;sub&gt;n&lt;/sub&gt;D) at altitudes of 75 km and 90 km for Singapore station. While performing the analysis, the solar maxima and solar minima epochs of the sun for 21st, 22nd and 23rd solar cycles (SCs) are taken into account. Before applying the model for the statistical analysis of the relationship, the stationary of the variables is investigated by using the unit root test. The relationship between the variables is also investigated by using the co-integration test. The relationship between N&lt;sub&gt;n&lt;/sub&gt;D measured at 75 km altitude and QBO obtained at altitude of 10 hPa is observed that it is positive for solar maximum epoch at 21st and 23rd SCs and for solar minimum epoch at 21st SC and is negative at the other epochs. The relationship between N&lt;sub&gt;n&lt;/sub&gt;D measured at 90 km altitude and QBO is observed to be negative at both the solar maxima expect for solar maximum of 23rd SC and the solar minima epochs. The relationship between variables is positive for both phases (east and west) of QBO. Thus, QBO leads to a statistical change in the N&lt;sub&gt;n&lt;/sub&gt;D. It may also give rise to changes on the ion chemistry of the D region.&lt;/p&gt;

Optical observations of the fast declining Type Ib supernova iPTF13bvn

We present optical UBVRI photometry and medium resolution spectroscopy of the type Ib supernova iPTF13bvn, spanning a phase of $\sim$ $-13\,$d to $+71\,$d with respect to $B$-band maximum. The post maximum decline rates indicate a fast decline with $\Delta m_{15}(B) = 1.82$. Correcting for a galactic extinction $E(B-V){\rm_{MW}}=0.045$ and host galaxy extinction of $E(B-V){\rm_{host}}=0.17$, the absolute $V$-band magnitude peaks at M$_V=-17.23\, \pm \,0.20$. The bolometric light curve indicates that $\sim 0.09$ M$_{\odot}$ of $^{56}$Ni was synthesized in the explosion. The earliest spectrum ($-13$d) shows the presence of He~{\sc i} 5876 \AA\ feature at a velocity of $\sim$15000 km s$^{-1}$, which falls rapidly by the time the SN approaches the epoch of B-band maximum. The photospheric velocity near maximum light, as indicated by the Fe~{\sc ii} 5169~\AA\ feature, is $\sim 9000$ km s$^{-1}$. The estimate for the $^{56}$Ni mass, together with the estimates for the ejected mass ($M_{\rm{ej}}$) and kinetic energy of the explosion ($E_{\rm{k}}$) indicate that iPTF13bvn is a low luminosity type Ib supernova, with a lower than average ejected mass and kinetic energy. Our results suggest that the progenitor of iPTF13bvn is inconsistent with a single Wolf-Rayet star.