Evolution of helicity in NOAA 10923 over three consecutive solar rotations

We have studied the evolution of magnetic helicity and chirality in an active region over three consecutive solar rotations. The region when it first appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA 10930, 10935 and 10941. We compare the chirality of these regions at photospheric, chromospheric and coronal heights. The observations used for photospheric and chromospheric heights are taken from Solar Vector Magnetograph (SVM) and H_alpha imaging telescope of Udaipur Solar Observatory (USO), respectively. We discuss the chirality of the sunspots and associated H_alpha filaments in these regions. We find that the twistedness of superpenumbral filaments is maintained in the photospheric transverse field vectors also. We also compare the chirality at photospheric and chromospheric heights with the chirality of the associated coronal loops, as observed from the HINODE X-Ray Telescope.Comment: 8 pages, 4 figure

Giant cell tumour of the flexor tendon sheath of the hand

Background: Giant cell tumor of tendon sheath is a benign soft tissue lesion most commonly found in the flexor aspect of hand and wrist. Recurrence of the tumor is common even after excision.Methods: It is an observational study where we present a review of 10 cases for which excision was done and were kept for regular follow up for minimum 6 months.Results: No recurrences noted in our series with minimum six months to maximum two years follow-up though review literature shows 10-40% recurrence rates.Conclusions: Complete excision with regular follow up care is indicated for this neoplasm due to its high propensity towards recurrence. The most important factor deciding recurrence pattern is incomplete excision and leaving behind satellite nodules.

A comparison of univariate methods for forecasting electricity demand up to a day ahead

This empirical paper compares the accuracy of six univariate methods for short-term electricity demand forecasting for lead times up to a day ahead. The very short lead times are of particular interest as univariate methods are often replaced by multivariate methods for prediction beyond about six hours ahead. The methods considered include the recently proposed exponential smoothing method for double seasonality and a new method based on principal component analysis (PCA). The methods are compared using a time series of hourly demand for Rio de Janeiro and a series of half-hourly demand for England and Wales. The PCA method performed well, but, overall, the best results were achieved with the exponential smoothing method, leading us to conclude that simpler and more robust methods, which require little domain knowledge, can outperform more complex alternatives

Polaronic Heat Capacity in The Anderson - Hasegawa Model

An exact treatment of the Anderson - Hasegawa two - site model, incorporating the presence of superexchange and polarons, is used to compute the heat capacity. The calculated results point to the dominance of the lattice contribution, especially in the ferromagnetic regime. This behavior is in qualitative agreement with experimental findings.Comment: 9 pages, Revtex, 4 postscript figure

Osteosclerosis in the extinct Cayaoa Bruneti (Aves, anseriformes) : insights on behavior and fligftlessness

Fil: Mendoza, Ricardo de. División Paleontología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La PlataFil: Tambussi, Claudia Patricia. Centro de Investigaciones en Ciencias de la Tierra (CICTERRA). Universidad Nacional de Córdoba; Argentin

Locating positions of {\gamma}-ray--emitting regions in blazars

We propose a new method to locate the gamma-ray--emitting positions R_g from the measured time lags T_ob of gamma-ray emission relative to broad emission lines. The method is also applicable to lower frequencies. R_g depends on parameters T_ob, R_BLR, v_d and theta, where R_BLR is the size of broad-line region, v_d is the travelling speed of disturbances down the jet and theta is the viewing angle of the jet axis to the line of sight. As T_ob=0, T_ob<0 or T_ob>0, the broad lines zero-lag, lag or lead the gamma-rays, respectively. It is applied to 3C 273, in which the lines and the radio emission have enough data, but the gamma-rays have not. We find T_ob0 for the 5, 8, 15, 22 and 37 GHz emission relative to the broad lines Ha, Hb and Hg. The lag may be positive or negative, however current data do not allow to discriminate between the two cases. The measured lags are on the order of years. For a given line, T_ob generally decreases as radio frequency increases. This trend most likely results from the radiative cooling of relativistic electrons. The negative lags have an average of T_ob=-2.86 years for the 37 GHz emission, which represents that the lines lag the radio emission. The positive lags have T_ob=3.20 years, which represents that the lines lead the radio emission. We obtain the radio emitting positions R_radio=0.40--2.62 pc and R_radio=9.43--62.31 pc for the negative and positive lags, respectively. From the constraint of R_g </~ R_radio (e.g. Dermer & Schlickeiser 1994; Jorstad et al. 2001), we have R_g </~ 0.40--2.62 pc for the negative lags. For the positive lags, 4.67--30.81<R_g </~ 9.43--62.31 pc. These estimated R_g are consistent with those of other researches. These agreements confirm the reliability of the method and assumptions. The method may be also applicable to BL Lacertae objects, in which broad lines were detected.Comment: 13 pages, 8 figures, MNRAS, acceptanc

Kaluza-Klein Type Robertson Walker Cosmological Model With Dynamical Cosmological Term Λ\Lambda

In this paper we have analyzed the Kaluza-Klein type Robertson Walker (RW) cosmological models by considering three different forms of variable $\Lambda$: $\Lambda\sim(\frac{\dot{a}}{a})^2$,$\Lambda\sim(\frac{\ddot{a}} {a})$ and $\Lambda \sim \rho$. It is found that, the connecting free parameters of the models with cosmic matter and vacuum energy density parameters are equivalent, in the context of higher dimensional space time. The expression for the look back time, luminosity distance and angular diameter distance are also derived. This work has thus generalized to higher dimensions the well-known results in four dimensional space time. It is found that there may be significant difference in principle at least, from the analogous situation in four dimensional space time.Comment: 16 pages, no figur

Dark sectors 2016 Workshop: community report

This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years