Results 71 to 80 of about 3,105 (240)

Was one sunspot cycle in the 18th century really lost?

, 2002
The unusually long 4th solar cycle has recently been proposed by Usoskin et al. (2001) to be composed of two cycles. They argue that a weak and short cycle might have been lost in sparse sunspot data at the end of the 18th century.
Krivova, N., S. K. Solanki, J. Beer, Solanki, S. K., N. A. Krivova, Solanki, S., Krivova, N. A., Beer, J.   +7 more
core   +1 more source

Rational Expectations Fools' Bubbles

International Economic Review, EarlyView.
ABSTRACT We develop a rational, Walrasian model of speculative bubbles inspired by the Kindleberger–Minsky view, which describes bubbles as wave‐like market processes. Touched off by an initial shock, price booms are initially self‐reinforcing but become self‐destructive later when prices surpass fundamental value.
Luis Araujo, Antonio Doblas‐Madrid
wiley   +1 more source

Solar Activity Spikes: A Comparative Analysis of Monthly Smoothed and Unsmoothed Sunspot Numbers

Universe
This work investigates the differences between the monthly and 13-month smoothed sunspot numbers since 1749, using data from sunspot number (version 2).
Víctor M. S. Carrasco, Alejandro J. P. Aparicio, Lucía Bautista, María Cruz Gallego, José M. Vaquero   +4 more
doaj   +1 more source

Evidence for Solar Modulation on the Millennial-Scale Climate Change of Earth

Universe, 2020
In this study, we use available reconstructed data to investigate periodicities of solar activity (i.e., sunspot number) and the Earth’s climate change (temperatures of Lake Qinghai in China and Vostok in Antarctica, the GISP δ18O climate record of ...
Xinhua Zhao, Willie Soon, Victor M. Velasco Herrera   +2 more
doaj   +1 more source

The positive correlation between the progressive photoreceptor damage and the increased macular leakage indicating the severity of diabetic retinopathy

Journal of Diabetes Investigation, EarlyView.
The dark area of photoreceptor cells, as measured by adaptive optics laser scanning ophthalmoscopy, shows significant enlargement with the progression of diabetic retinopathy (DR). A similar trend is observed for macular vascular leakage assessed by fundus fluorescein angiography. A positive correlation exists between these two parameters, suggesting a
Qi Fang, Bingjie Qiu, Xinyue Xu, Wei Jia, Ru Wang, Qianfeng Wang, Wei Qiang, Lei Zhang, Jingfa Zhang, Haiyan Wang   +9 more
wiley   +1 more source

Time series modelling of sunspot numbers using long range cyclical dependence [PDF]

This paper deals with the analysis of the monthly structure of sunspot numbers using a new technique based on cyclical long range dependence. The results show that sunspot numbers have a periodicity of 130 months, but more importantly, that the series is
Luis A. Gil-Alana
core  

The lost sunspot cycle: New support from

, 2015
It has been suggested that the shortage in the number of spots on the surface of the Sun between 1790 and 1830, known as the Dalton minimum, contained an extra cycle that was not identified in the original sunspot record by Wolf.
C. Karoff, M. F. Knudsen, A. Fogtmann-Schulz, F. Inceoglu, J. Olsen   +4 more
core   +1 more source

Why Does the Sun's Torsional Oscillation Begin before the Sunspot Cycle? [PDF]

, 2009
Although the Sun's torsional oscillation is believed to be driven by the Lorentz force associated with the sunspot cycle, this oscillation begins 2-3 yr before the sunspot cycle.
Choudhuri, Arnab Rai, Chakraborty, Sagar, Chatterjee, Piyali, Rai Choudhuri, Arnab   +3 more
core   +1 more source

Detecting Periodicity of a General Stationary Time Series via AR(2)‐Model Fitting

Journal of Time Series Analysis, EarlyView.
ABSTRACT Estimating the periodicity of a stationary time series via fitting a second‐order stationary autoregressive (AR(2)) model has been initiated by the seminal paper of Yule (1927). We investigate properties of this procedure when applied to general stationary processes possessing a spectral density with a dominant peak at some unknown frequency ...
Jens‐Peter Kreiss, Panagiotis Maouris, Efstathios Paparoditis   +2 more
wiley   +1 more source

Predicting the Sunspot Cycle

, 2009
The 11-year sunspot cycle was discovered by an amateur astronomer in 1844. Visual and photographic observations of sunspots have been made by both amateurs and professionals over the last 400 years.
Hathaway, David H.
core