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Rotation is a prominent feature of the Sun, and it plays a crucial role in the generation and dynamic evolution of solar magnetic fields. The daily composite time series of Ca II K plage areas from 1907 February 1 to 2023 December 31 is…
The historical Hungarian auroral record extends from 1523 to 1960 and is longer than the sunspot record. Harmonic analysis reveals four major multidecadal secular cycles forming an approximate harmonic set at periods of 42.85, 57.13, 85.7…
Frequency splitting coefficients from Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations covering the period 1995--2001 are used to study temporal variations in the solar rotation rate at high latitudes.…
Periodic trees are combinatorial structures which are in bijection with cluster tilting objects in cluster categories of affine type $\tilde{A}_{n-1}$. The internal edges of the tree encode the $c$-vectors corresponding to the cluster…
We present the results of a time-series analysis of 130 echelle spectra of epsilon Ori (B0 Ia), acquired over seven observing seasons between 1998 and 2006 at Ritter Observatory. The equivalent widths of Halpha (net) and He I 5876 were…
Solar prominences are structures of importance because of their role in polar field reversal. We study the long-term variation of the time latitude distribution of solar prominences in this article. To accomplish this, we primarily used the…
Sequences with low aperiodic autocorrelation are used in communications and remote sensing for synchronization and ranging. The autocorrelation demerit factor of a sequence is the sum of the squared magnitudes of its autocorrelation values…
Longitudinal distributions of the photospheric magnetic field studied on the base of National Solar Observatory (Kitt Peak) data (1976 - 2003) displayed two opposite patterns during different parts of the 11-year solar cycle.…
Extinction coefficients and sensitivity values in the JHKL band-passes measured on nearly 200 nights of observing between 1978 and 1992 on the 1.5-meter and the Blanco 4- meter telescopes at Cerro Tololo Inter-American Observatory are…
We present an analysis of photometric observations of the eclipsing novalike variable DW UMa made by the CBA consortium between 1999 and 2015. Analysis of 372 new and 260 previously published eclipse timings reveals a 13.6 year period or…
We consider the polarization of thermal emission in the near-field of various materials including dielectrics and metallic systems with resonant surface modes. We find that at thermal equilibrium, the degree of polarization exhibits spatial…
Ice cores are known to yield information about astronomical phenomena as well as information about past climate. We report time series analyses of annually resolved nitrate variations in an ice core, drilled at the Dome Fuji station in East…
We study the inhomogeneous continuum random trees (ICRT) that arise as weak limits of birthday trees. We give a description of the exploration process, a function defined on [0,1] that encodes the structure of an ICRT, and also of its width…
In this paper we consider the variational approach to cactus trees (Husimi trees) and the more common recursive approach, that are in principle equivalent for finite systems. We discuss in detail the conditions under which the two methods…
The family of Tibetan lunisolar calendars operates on a shared arithmetic axiom (67 lunar months = 65 solar months) that provides a rigid structure but causes observable seasonal drift. This study deconstructs the calendar through a…
Decadal climate predictions, which are initialized with observed conditions, are characterized by two main sources of uncertainties--internal and model variabilities. Using an ensemble of climate model simulations from the CMIP5 decadal…
In this paper, an analysis of hourly air temperatures in four groups of 32 stations of the UK highland (five stations), UK lowland (four stations), Italian highland (eleven stations), and Italian lowland (twelve stations) at various…
At high frequencies beyond the acoustic cut-off, a peak-like structure is visible in the solar power spectrum. Known as the pseudo-modes, their frequencies have been shown to vary in anti-phase with solar magnetic activity. In this work, we…
Recent studies of the optical/UV and X-ray ephemerides of X1822-371 have found some discrepancies in the value of the orbital period derivative. Because of the importance of this value in constraining the system evolution, we…
What transpires from recent research is that temperatures and radiative forcing seem to be characterized by a linear trend with two changes in the rate of growth. The first occurs in the early 60s and indicates a very large increase in the…