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Sample records for sunspot cycle period

  1. The sunspot cycle revisited

    International Nuclear Information System (INIS)

    Lomb, Nick

    2013-01-01

    The set of sunspot numbers observed since the invention of the telescope is one of the most studied time series in astronomy and yet it is also one of the most complex. Fourteen frequencies are found in the yearly mean sunspot numbers from 1700 to 2011using the Lomb-Scargle periodogram and prewhitening. All of the frequencies corresponding to shorter term periods can be matched with simple algebraic combinations of the frequency of the main 11-year period and the frequencies of the longer term periods in the periodogram. This is exactly what can be expected from amplitude and phase modulation of an 11.12-year periodicity by longer term variations. Similar, though not identical, results are obtained after correcting the sunspot number series as proposed by Svalgaard. On looking separately at the amplitude and phase modulation a clear relationship is found between the two modulations although this relationship has broken down for the last four solar cycles. The phase modulation implies that there is a definite underlying period for the solar cycle. Such a clock mechanism does seem to be a possibility in models of the solar dynamo incorporating a conveyor-belt-like meridional circulation between high polar latitudes and the equator.

  2. Nature's third cycle a story of sunspots

    CERN Document Server

    Choudhuri, Arnab Rai

    2015-01-01

    The cycle of day and night and the cycle of seasons are two familiar natural cycles around which many human activities are organized. But is there a third natural cycle of importance for us humans? On 13 March 1989, six million people in Canada went without electricity for many hours: a large explosion on the sun was discovered as the cause of this blackout. Such explosions occur above sunspots, dark features on the surface of the Sun that have been observed through telescopes since the time of Galileo. The number of sunspots has been found to wax and wane over a period of 11 years. Although this cycle was discovered less than two centuries ago, it is becoming increasingly important for us as human society becomes more dependent on technology. For nearly a century after its discovery, the cause of the sunspot cycle remained completely shrouded in mystery. The 1908 discovery of strong magnetic fields in sunspots made it clear that the 11-year cycle is the magnetic cycle of the sun. It is only during the last ...

  3. Skills, sunspots and cycles

    DEFF Research Database (Denmark)

    Busato, Francesco; Marchetti, Enrico

    This paper explores the ability of a class of one-sector,multi-input models to generate indeterminate equilibrium paths, andendogenous cycles, without relying on factors' hoarding. The modelpresents a novel theoretical economic mechanism that supportssunspot-driven expansions without requiring...

  4. Long-term periodicities in the sunspot record

    International Nuclear Information System (INIS)

    Wilson, R.M.

    1984-07-01

    Sunspot records are systematically maintained, with the knowledge that an 11 year average period exists since about 1850. Thus, the sunspot record of highest quality and considered to be the most reliable is that of cycle eight through the present. On the basis of cycles 8 through 20, various combinations of sine curves were used to approximate the observed R sub MAX values (where R sub MAX is the smoothed sunspot number at cycle maximum). It is found that a three component sinusoidal function, having an 11 cycle and a 2 cycle variation on a 90 cycle periodicity, yields computed R sub MAX values which fit, reasonably well, observed R sub MAX values for the modern sunspot cycles. Extrapolation of the empirical functions forward in time allows for the projection of values of R sub MAX for cycles 21 and 22. For cycle 21, the function projects a value of 157.3, very close to the actually observed value of 164.5. For cycle 22, the function projects a value of about 107. Linear regressions applied to cycle 22 indicate a long-period cycle (cycle duration 132 months). An extensive bibliography on techniques used to estimate the time dependent behavior of sunspot cycles is provided

  5. Are climatological correlations with the Hale double sunspot cycle meaningful

    International Nuclear Information System (INIS)

    Goldberg, R.A.; Herman, J.R.

    1975-09-01

    A sunspot cycle which may have been subject to a predicted phase reversal between 1800 and 1880 A.D. is discussed. Several climatological parameters normally correlated with this cycle are examined and do not exhibit a corresponding phase reversal during this period. It is proposed that this apparent discrepency can be resolved by suitable observations during the upcoming half decade

  6. Revised Sunspot Numbers and the Effects on Understanding the Sunspot Cycle

    Science.gov (United States)

    Hathaway, D. H.

    2014-12-01

    While sunspot numbers provide only limited information about the sunspot cycle, they provide that information for at least twice as many sunspot cycles as any other direct solar observation. In particular, sunspot numbers are available before, during, and immediately after the Maunder Minimum (1645-1715). The instruments and methods used to count sunspots have changed over the last 400+ years. This leads to systematic changes in the sunspot number that can mask, or artificially introduce, characteristics of the sunspot cycle. The most widely used sunspot number is the International (Wolf/Zurich) sunspot number which is now calculated at the Solar Influences Data Center in Brussels, Belgium. These numbers extend back to 1749. The Group sunspot number extends back to the first telescopic observations of the Sun in 1610. There are well-known and significant differences between these two numbers where they overlap. Recent work has helped us to understand the sources of these differences and has led to proposed revisions in the sunspot numbers. Independent studies now support many of these revisions. These revised sunspot numbers suggest changes to our understanding of the sunspot cycle itself and to our understanding of its connection to climate change.

  7. Sunspots

    International Nuclear Information System (INIS)

    Moore, R.; Rabin, D.

    1985-01-01

    It is pointed out that the sun provides a close-up view of many astrophysically important phenomena, nearly all connected with the causes and effects of solar magnetic fields. The present article provides a review of the role of sunspots in a number of new areas of research. Connections with other solar phenomena are examined, taking into account flares, the solar magnetic cycle, global flows, luminosity variation, and global oscillations. A selective review of the structure and dynamic phenomena observed within sunspots is also presented. It is found that sunspots are usually contorted during the growth phase of an active region as magnetic field rapidly emerges and sunspots form, coalesce, and move past or even through each other. Attention is given to structure and flows, oscillations and waves, and plans for future studies. 145 references

  8. SUNSPOT CYCLES IMPACTS ON TOURISM AND QUALITY OF LIFE

    Directory of Open Access Journals (Sweden)

    Tadeja Jere Jakulin

    2017-09-01

    Full Text Available We live under the influence of natural cycles caused by the rotation of our planet and its revolution around the sun. The nature of our nearest star is also subject to cyclical change. This article presents a study of a correlation between sunspot cycles and foreign tourists arrivals in Slovenia, based on historical data between sunspot cycles and sea salt production in Slovenia's Municipality of Piran during the Maunder Minimum period (1645-1715. The production of salt by the solar evaporation of brine in salt pans and tourist industry are seasonal economic activities that are affected by changes to the weather. The paper looks at sea salt production in Piran during a particular period in the past. The repetition of the sea salt production in the past is not possible. For this reason, the study uses mathematical tools and an additional case study, which analyses arrivals of foreign tourists to Slovenia over the past 65 years (1948-2012. The study has two purposes: to identify a linear correlation coefficient, which provides evidence of a correlation between arrivals of foreign tourists to Slovenia and sunspot cycles and to develop a causal loop diagram (CLD or so called qualitative model of a complex tourism system, which shows the interdependency of sunspot cycles, tourism system, and quality of life.

  9. The Recalibrated Sunspot Number: Impact on Solar Cycle Predictions

    Science.gov (United States)

    Clette, F.; Lefevre, L.

    2017-12-01

    Recently and for the first time since their creation, the sunspot number and group number series were entirely revisited and a first fully recalibrated version was officially released in July 2015 by the World Data Center SILSO (Brussels). Those reference long-term series are widely used as input data or as a calibration reference by various solar cycle prediction methods. Therefore, past predictions may now need to be redone using the new sunspot series, and methods already used for predicting cycle 24 will require adaptations before attempting predictions of the next cycles.In order to clarify the nature of the applied changes, we describe the different corrections applied to the sunspot and group number series, which affect extended time periods and can reach up to 40%. While some changes simply involve constant scale factors, other corrections vary with time or follow the solar cycle modulation. Depending on the prediction method and on the selected time interval, this can lead to different responses and biases. Moreover, together with the new series, standard error estimates are also progressively added to the new sunspot numbers, which may help deriving more accurate uncertainties for predicted activity indices. We conclude on the new round of recalibration that is now undertaken in the framework of a broad multi-team collaboration articulated around upcoming ISSI workshops. We outline the future corrections that can still be expected in the future, as part of a permanent upgrading process and quality control. From now on, future sunspot-based predictive models should thus be made more adaptable, and regular updates of predictions should become common practice in order to track periodic upgrades of the sunspot number series, just like it is done when using other modern solar observational series.

  10. Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

    Directory of Open Access Journals (Sweden)

    V. Mussino

    1994-08-01

    Full Text Available Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r between geomagnetic indices and sunspot numbers for the ascending phases of sunspot cycles 9 to 22, confirming previous findings based on a minor number of sunspot cycles. The result is useful to researchers in topics related to solar-terrestrial physics, particularly for the interpretation of long-term trends in geomagnetic activity during the past, and to forecast geomagnetic activity levels in the future.

  11. Fractal Dimension and Maximum Sunspot Number in Solar Cycle

    Directory of Open Access Journals (Sweden)

    R.-S. Kim

    2006-09-01

    Full Text Available The fractal dimension is a quantitative parameter describing the characteristics of irregular time series. In this study, we use this parameter to analyze the irregular aspects of solar activity and to predict the maximum sunspot number in the following solar cycle by examining time series of the sunspot number. For this, we considered the daily sunspot number since 1850 from SIDC (Solar Influences Data analysis Center and then estimated cycle variation of the fractal dimension by using Higuchi's method. We examined the relationship between this fractal dimension and the maximum monthly sunspot number in each solar cycle. As a result, we found that there is a strong inverse relationship between the fractal dimension and the maximum monthly sunspot number. By using this relation we predicted the maximum sunspot number in the solar cycle from the fractal dimension of the sunspot numbers during the solar activity increasing phase. The successful prediction is proven by a good correlation (r=0.89 between the observed and predicted maximum sunspot numbers in the solar cycles.

  12. Statistics of the largest sunspot and facular areas per solar cycle

    International Nuclear Information System (INIS)

    Willis, D.M.; Kabasakal Tulunay, Y.

    1979-01-01

    The statistics of extreme values is used to investigate the statistical properties of the largest areas sunspots and photospheric faculae per solar cycle. The largest values of the synodic-solar-rotation mean areas of umbrae, whole spots and faculae, which have been recorded for nine solar cycles, are each shown to comply with the general form of the extreme value probability function. Empirical expressions are derived for the three extreme value populations from which the characteristic statistical parameters, namely the mode, median, mean and standard deviation, can be calculated for each population. These three extreme value populations are also used to find the expected ranges of the extreme areas in a group of solar cycles as a function of the number of cycles in the group. The extreme areas of umbrae and whole spots have a dispersion comparable to that found by Siscoe for the extreme values of sunspot number, whereas the extreme areas of faculae have a smaller dispersion which is comparable to that found by Siscoe for the largest geomagnetic storm per solar cycle. The expected range of the largest sunspot area per solar cycle for a group of one hundred cycles appears to be inconsistent with the existence of the prolonged periods of sunspot minima that have been inferred from the historical information on solar variability. This inconsistency supports the contention that there are temporal changes of solar-cycle statistics during protracted periods of sunspot minima (or maxima). Indeed, without such temporal changes, photospheric faculae should have been continually observable throughout the lifetime of the Sun. (orig.)

  13. Sunspots

    International Nuclear Information System (INIS)

    Priest, E.R.

    1982-01-01

    The existence of sunspots has been known since ancient times, but it was only at the beginning of this century that they were found to be the sites of very strong magnetic fields, and it was realised that they represent the places where huge magnetic flux tubes burst through the solar surface. A theoretical understanding of sunspots has had to await the development of magnetohydrodynamics; however, even now, there is some controversy about answers to fundamental questions, such as: why is a sunspot cool, what is its equilibrium structure and how is it formed. Other topics that are discussed in the present chapter include magnetoconvection and the process of magnetic buoyancy whereby a flux tube deep within the Sun tends to rise towards the surface because it is lighter than its surroundings. Outside active regions the magnetic flux is not spread out uniformly to a weak field of a few Gauss, but instead it is mainly concentrated at supergranulation boundaries into intense flux tubes, whose properties are discussed. (Auth.)

  14. SOLAR CYCLE 24: CURIOUS CHANGES IN THE RELATIVE NUMBERS OF SUNSPOT GROUP TYPES

    International Nuclear Information System (INIS)

    Kilcik, A.; Yurchyshyn, V. B.; Ozguc, A.; Rozelot, J. P.

    2014-01-01

    Here, we analyze different sunspot group (SG) behaviors from the points of view of both the sunspot counts (SSCs) and the number of SGs, in four categories, for the time period of 1982 January-2014 May. These categories include data from simple (A and B), medium (C), large (D, E, and F), and decaying (H) SGs. We investigate temporal variations of all data sets used in this study and find the following results. (1) There is a very significant decrease in the large groups' SSCs and the number of SGs in solar cycle 24 (cycle 24) compared to cycles 21-23. (2) There is no strong variation in the decaying groups' data sets for the entire investigated time interval. (3) Medium group data show a gradual decrease for the last three cycles. (4) A significant decrease occurred in the small groups during solar cycle 23, while no strong changes show in the current cycle (cycle 24) compared to the previous ones. We confirm that the temporal behavior of all categories is quite different from cycle to cycle and it is especially flagrant in solar cycle 24. Thus, we argue that the reduced absolute number of the large SGs is largely, if not solely, responsible for the weak cycle 24. These results might be important for long-term space weather predictions to understand the rate of formation of different groups of sunspots during a solar cycle and the possible consequences for the long-term geomagnetic activity

  15. Sunspot variation and selected associated phenomena: a look at solar cycle 21 and beyond

    International Nuclear Information System (INIS)

    Wilson, R.M.

    1982-02-01

    Solar sunspot cycles 8 through 21 are reviewed. Mean time intervals are calculated for maximum to maximum, minimum to minimum, minimum to maximum, and maximum to minimum phases for cycles 8 through 20 and 8 through 21. Simple cosine functions with a period of 132 years are compared to, and found to be representative of, the variation of smoothed sunspot numbers at solar maximum and minimum. A comparison of cycles 20 and 21 is given, leading to a projection for activity levels during the Spacelab 2 era (tentatively, November 1984). A prediction is made for cycle 22. Major flares are observed to peak several months subsequent to the solar maximum during cycle 21 and to be at minimum level several months after the solar minimum. Additional remarks are given for flares, gradual rise and fall radio events and 2800 MHz radio emission. Certain solar activity parameters, especially as they relate to the near term Spacelab 2 time frame are estimated

  16. Deciphering solar magnetic activity. I. On the relationship between the sunspot cycle and the evolution of small magnetic features

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W.; Wang, Xin; Markel, Robert S.; Thompson, Michael J. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Leamon, Robert J.; Malanushenko, Anna V. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Davey, Alisdair R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Howe, Rachel [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Krista, Larisza D. [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80205 (United States); Cirtain, Jonathan W. [Marshall Space Flight Center, Code ZP13, Huntsville, AL 35812 (United States); Gurman, Joseph B.; Pesnell, William D., E-mail: mscott@ucar.edu [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-09-01

    Sunspots are a canonical marker of the Sun's internal magnetic field which flips polarity every ∼22 yr. The principal variation of sunspots, an ∼11 yr variation, modulates the amount of the magnetic field that pierces the solar surface and drives significant variations in our star's radiative, particulate, and eruptive output over that period. This paper presents observations from the Solar and Heliospheric Observatory and Solar Dynamics Observatory indicating that the 11 yr sunspot variation is intrinsically tied to the spatio-temporal overlap of the activity bands belonging to the 22 yr magnetic activity cycle. Using a systematic analysis of ubiquitous coronal brightpoints and the magnetic scale on which they appear to form, we show that the landmarks of sunspot cycle 23 can be explained by considering the evolution and interaction of the overlapping activity bands of the longer-scale variability.

  17. Investigation of Quasi-periodic Solar Oscillations in Sunspots Based on SOHO/MDI Magnetograms

    Science.gov (United States)

    Kallunki, J.; Riehokainen, A.

    2012-10-01

    In this work we study quasi-periodic solar oscillations in sunspots, based on the variation of the amplitude of the magnetic field strength and the variation of the sunspot area. We investigate long-period oscillations between three minutes and ten hours. The magnetic field synoptic maps were obtained from the SOHO/MDI. Wavelet (Morlet), global wavelet spectrum (GWS) and fast Fourier transform (FFT) methods are used in the periodicity analysis at the 95 % significance level. Additionally, the quiet Sun area (QSA) signal and an instrumental effect are discussed. We find several oscillation periods in the sunspots above the 95 % significance level: 3 - 5, 10 - 23, 220 - 240, 340 and 470 minutes, and we also find common oscillation periods (10 - 23 minutes) between the sunspot area variation and that of the magnetic field strength. We discuss possible mechanisms for the obtained results, based on the existing models for sunspot oscillations.

  18. The use of solar faculae in studies of the sunspot cycle

    International Nuclear Information System (INIS)

    Brown, G.M.; Evans, R.

    1980-01-01

    Comparison of the long-term variation of photospheric faculae areas with that of sunspots shows that studies of faculae provide both complementary and supplementary information on the behaviour of the solar cycle. Detailed studies of the development of sunspots with respect to faculae show that there is a high degree of order over much of a given cycle, but marked differences from cycle to cycle. Within a cycle the relationship between spot and faculae areas appears to be similar for the N and S solar hemispheres, and over the early stages of a cycle it is directly related to the magnitude of the maximum sunspot number subsequently attained in that cycle. This result may well have predictive applications, and formulae are given relating the peak sunspot number to simple parameters derived from this early developmental stage. Full application to the current cycle 21 is denied due to the cessation of the Greenwich daily photoheliographic measurements, but use of the cruder weekly data suggests a maximum smoothed sunspot number of 150 +- 22. The effects of the incompatibility of the spot and faculae data, in that faculae are unobservable over a large fraction of the solar disc and also do not always develop associated spots, have been examined in a detailed study of two cycles and shown not to vitiate the results. (orig.)

  19. Temporal and Periodic Variations of Sunspot Counts in Flaring and Non-Flaring Active Regions

    Science.gov (United States)

    Kilcik, A.; Yurchyshyn, V.; Donmez, B.; Obridko, V. N.; Ozguc, A.; Rozelot, J. P.

    2018-04-01

    We analyzed temporal and periodic variations of sunspot counts (SSCs) in flaring (C-, M-, or X-class flares), and non-flaring active regions (ARs) for nearly three solar cycles (1986 through 2016). Our main findings are as follows: i) temporal variations of monthly means of the daily total SSCs in flaring and non-flaring ARs behave differently during a solar cycle and the behavior varies from one cycle to another; during Solar Cycle 23 temporal SSC profiles of non-flaring ARs are wider than those of flaring ARs, while they are almost the same during Solar Cycle 22 and the current Cycle 24. The SSC profiles show a multi-peak structure and the second peak of flaring ARs dominates the current Cycle 24, while the difference between peaks is less pronounced during Solar Cycles 22 and 23. The first and second SSC peaks of non-flaring ARs have comparable magnitude in the current solar cycle, while the first peak is nearly absent in the case of the flaring ARs of the same cycle. ii) Periodic variations observed in the SSCs profiles of flaring and non-flaring ARs derived from the multi-taper method (MTM) spectrum and wavelet scalograms are quite different as well, and they vary from one solar cycle to another. The largest detected period in flaring ARs is 113± 1.6 days while we detected much longer periodicities (327± 13, 312 ± 11, and 256± 8 days) in the non-flaring AR profiles. No meaningful periodicities were detected in the MTM spectrum of flaring ARs exceeding 55± 0.7 days during Solar Cycles 22 and 24, while a 113± 1.3 days period was detected in flaring ARs of Solar Cycle 23. For the non-flaring ARs the largest detected period was only 31± 0.2 days for Cycle 22 and 72± 1.3 days for the current Cycle 24, while the largest measured period was 327± 13 days during Solar Cycle 23.

  20. Influence of the sunspot cycle on the Northern Hemisphere wintertime circulation from long upper-air data sets

    Directory of Open Access Journals (Sweden)

    Y. Brugnara

    2013-07-01

    Full Text Available Here we present a study of the 11 yr sunspot cycle's imprint on the Northern Hemisphere atmospheric circulation, using three recently developed gridded upper-air data sets that extend back to the early twentieth century. We find a robust response of the tropospheric late-wintertime circulation to the sunspot cycle, independent from the data set. This response is particularly significant over Europe, although results show that it is not directly related to a North Atlantic Oscillation (NAO modulation; instead, it reveals a significant connection to the more meridional Eurasian pattern (EU. The magnitude of mean seasonal temperature changes over the European land areas locally exceeds 1 K in the lower troposphere over a sunspot cycle. We also analyse surface data to address the question whether the solar signal over Europe is temporally stable for a longer 250 yr period. The results increase our confidence in the existence of an influence of the 11 yr cycle on the European climate, but the signal is much weaker in the first half of the period compared to the second half. The last solar minimum (2005 to 2010, which was not included in our analysis, shows anomalies that are consistent with our statistical results for earlier solar minima.

  1. Relationship between geomagnetic classes’ activity phases and their occurrence during the sunspot cycle

    Directory of Open Access Journals (Sweden)

    Frédéric Ouattara

    2009-06-01

    Full Text Available Four well known geomagnetic classes of activity such as quiet days activity, fluctuating activity, recurrent activity
    and shock activity time occurrences have been determined not only by using time profile of sunspot number
    Rz but also by using aa index values.
    We show that recurrent wind stream activity and fluctuating activity occur in opposite phase and slow solar wind
    activity during minimum phase and shock activity at the maximum phase.
    It emerges from this study that fluctuating activity precedes the sunspot cycle by π/2 and the latter also precedes
    recurrent activity by π/2. Thus in the majority the activities do not happen at random; the sunspot cycle starts
    with quiet days activity, continues with fluctuating activity and during its maximum phase arrives shock activity.
    The descending phase is characterized by the manifestation of recurrent wind stream activity.

  2. Using dynamo theory to predict the sunspot number during solar cycle 21

    Science.gov (United States)

    Schatten, K. H.; Scherrer, P. H.; Svalgaard, L.; Wilcox, J. M.

    1978-01-01

    On physical grounds it is suggested that the polar field strength of the sun near a solar minimum is closely related to the solar activity of the following cycle. Four methods of estimating the polar magnetic field strength of the sun near solar minimum are employed to provide an estimate of the yearly mean sunspot number of cycle 21 at solar maximum of 140 + or - 20. This estimate may be considered a first-order attempt to predict the cycle activity using one parameter of physical importance based upon dynamo theory.

  3. Sunspot Cycle Prediction Using Multivariate Regression and Binary ...

    Indian Academy of Sciences (India)

    49

    Multivariate regression model has been derived based on the available cycles 1 .... The flare index correlates well with various parameters of the solar activity. ...... 32) Sabarinath A and Anilkumar A K 2011 A stochastic prediction model for the.

  4. TIME DISTRIBUTIONS OF LARGE AND SMALL SUNSPOT GROUPS OVER FOUR SOLAR CYCLES

    International Nuclear Information System (INIS)

    Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Cao, W.; Ozguc, A.; Rozelot, J. P.

    2011-01-01

    Here we analyze solar activity by focusing on time variations of the number of sunspot groups (SGs) as a function of their modified Zurich class. We analyzed data for solar cycles 20-23 by using Rome (cycles 20 and 21) and Learmonth Solar Observatory (cycles 22 and 23) SG numbers. All SGs recorded during these time intervals were separated into two groups. The first group includes small SGs (A, B, C, H, and J classes by Zurich classification), and the second group consists of large SGs (D, E, F, and G classes). We then calculated small and large SG numbers from their daily mean numbers as observed on the solar disk during a given month. We report that the time variations of small and large SG numbers are asymmetric except for solar cycle 22. In general, large SG numbers appear to reach their maximum in the middle of the solar cycle (phases 0.45-0.5), while the international sunspot numbers and the small SG numbers generally peak much earlier (solar cycle phases 0.29-0.35). Moreover, the 10.7 cm solar radio flux, the facular area, and the maximum coronal mass ejection speed show better agreement with the large SG numbers than they do with the small SG numbers. Our results suggest that the large SG numbers are more likely to shed light on solar activity and its geophysical implications. Our findings may also influence our understanding of long-term variations of the total solar irradiance, which is thought to be an important factor in the Sun-Earth climate relationship.

  5. Universal cycle periods

    NARCIS (Netherlands)

    Groot, de E.A. (Bert); Franses, P.H.P.H.

    2009-01-01

    We present a meta-analysis of cycles in historical economic data. The literature on stochastic and deterministic cycles in variables such as the consumer price index, employment, interest rates, commodity prices, and GDP is huge and scattered, but our meta-analysis reveals various communalities. Our

  6. Probability Estimates of Solar Proton Doses During Periods of Low Sunspot Number for Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William F.; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper presented at ICES in 2015, we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the monthly smoothed sunspot number (SSN) was less than 30. Although such months are generally considered "solar-quiet", SPEs observed during these months even include Ground Level Events, the most energetic type of SPE. In this paper, we add to previous study those SPEs that occurred in 1973-2015 when the SSN was greater than 30 but less than 50. Based on the observable energy range of the solar protons, we classify the event as GLEs, sub-GLEs, and sub-sub-GLEs, all of which are potential contributors to the radiation hazard. We use the spectra of these events to construct a probabilistic model of the absorbed dose due to solar protons when SSN < 50 at various confidence levels for various depths of shielding and for various mission durations. We provide plots and tables of solar proton-induced absorbed dose as functions of confidence level, shielding thickness, and mission-duration that will be useful to system designers.

  7. A dynamo theory prediction for solar cycle 22: Sunspot number, radio flux, exospheric temperature, and total density at 400 km

    Science.gov (United States)

    Schatten, K. H.; Hedin, A. E.

    1986-01-01

    Using the dynamo theory method to predict solar activity, a value for the smoothed sunspot number of 109 + or - 20 is obtained for solar cycle 22. The predicted cycle is expected to peak near December, 1990 + or - 1 year. Concommitantly, F(10.7) radio flux is expected to reach a smoothed value of 158 + or - 18 flux units. Global mean exospheric temperature is expected to reach 1060 + or - 50 K and global total average total thermospheric density at 400 km is expected to reach 4.3 x 10 to the -15th gm/cu cm + or - 25 percent.

  8. A dynamo theory prediction for solar cycle 22 - Sunspot number, radio flux, exospheric temperature, and total density at 400 km

    Science.gov (United States)

    Schatten, K. H.; Hedin, A. E.

    1984-01-01

    Using the 'dynamo theory' method to predict solar activity, a value for the smoothed sunspot number of 109 + or - 20 is obtained for solar cycle 22. The predicted cycle is expected to peak near December, 1990 + or - 1 year. Concommitantly, F(10.7) radio flux is expected to reach a smoothed value of 158 + or - 18 flux units. Global mean exospheric temperature is expected to reach 1060 + or - 50 K and global total average total thermospheric density at 400 km is expected to reach 4.3 x 10 to the -15th gm/cu cm + or - 25 percent.

  9. Essential features of long-term changes of areas and diameters of sunspot groups in solar activity cycles 12-24

    Science.gov (United States)

    Efimenko, V. M.; Lozitsky, V. G.

    2018-06-01

    We analyze the Greenwich catalog data on areas of sunspot groups of last thirteen solar cycles. Various parameters of sunspots are considered, namely: average monthly smoothed areas, maximum area for each year and equivalent diameters of groups of sunspots. The first parameter shows an exceptional power of the 19th cycle of solar activity, which appears here more contrastively than in the numbers of spots (that is, in Wolf's numbers). It was found that in the maximum areas of sunspot groups for a year there is a unique phenomenon: a short and high jump in the 18th cycle (in 1946-1947) that has no analogues in other cycles. We also studied the integral distributions for equivalent diameters and found the following: (a) the average value of the index of power-law approximation is 5.4 for the last 13 cycles and (b) there is reliable evidence of Hale's double cycle (about 44 years). Since this indicator reflects the dispersion of sunspot group diameters, the results obtained show that the convective zone of the Sun generates embryos of active regions in different statistical regimes which change with a cycle of about 44 years.

  10. Predicting Maximum Sunspot Number in Solar Cycle 24 Nipa J Bhatt ...

    Indian Academy of Sciences (India)

    Key words. Sunspot number—precursor prediction technique—geo- magnetic activity index aa. 1. Introduction. Predictions of solar and geomagnetic activities are important for various purposes, including the operation of low-earth orbiting satellites, operation of power grids on. Earth, and satellite communication systems.

  11. Planetary tides during the Maunder sunspot minimum

    International Nuclear Information System (INIS)

    Smythe, C.M.; Eddy, J.A.

    1977-01-01

    Sun-centered planetary conjunctions and tidal potentials are here constructed for the AD1645 to 1715 period of sunspot absence, referred to as the 'Maunder Minimum'. These are found to be effectively indistinguishable from patterns of conjunctions and power spectra of tidal potential in the present era of a well established 11 year sunspot cycle. This places a new and difficult restraint on any tidal theory of sunspot formation. Problems arise in any direct gravitational theory due to the apparently insufficient forces and tidal heights involved. Proponents of the tidal hypothesis usually revert to trigger mechanisms, which are difficult to criticise or test by observation. Any tidal theory rests on the evidence of continued sunspot periodicity and the substantiation of a prolonged period of solar anomaly in the historical past. The 'Maunder Minimum' was the most drastic change in the behaviour of solar activity in the last 300 years; sunspots virtually disappeared for a 70 year period and the 11 year cycle was probably absent. During that time, however, the nine planets were all in their orbits, and planetary conjunctions and tidal potentials were indistinguishable from those of the present era, in which the 11 year cycle is well established. This provides good evidence against the tidal theory. The pattern of planetary tidal forces during the Maunder Minimum was reconstructed to investigate the possibility that the multiple planet forces somehow fortuitously cancelled at the time, that is that the positions of the slower moving planets in the 17th and early 18th centuries were such that conjunctions and tidal potentials were at the time reduced in number and force. There was no striking dissimilarity between the time of the Maunder Minimum and any period investigated. The failure of planetary conjunction patterns to reflect the drastic drop in sunspots during the Maunder Minimum casts doubt on the tidal theory of solar activity, but a more quantitative test

  12. Period of sunspot numbers is 11.02653720 years (11 years 9 days 16 hours 18 minutes 0 seconds)

    International Nuclear Information System (INIS)

    Norita, Sadataka

    1976-01-01

    In the statistical analysis of time series there have been applied usually the stationary stochastic process or the Markov stochastic process and recently there are applied remarkably an autoregressive process, a stochastic difference equation, an autoregressive-moving average process, a moving average process, the Whittaker periodogram, the correlogram, Schuster periodogram, chi-squared periodogram, level crossings, harmonic process, difference method, spectral density and first order vector equation, but in special case it is desirable to apply the nonstationary stocastic process. In this paper we introduce an stationarity into the autoregressive process and then it is the first purpose to compute precisely period of sunspot numbers. The result up to the eighth places at the decimal point was obtained that its period is 11.02653720 years, that is, 11 years 9 days 16 hours 18 minutes 0 seconds. This is considered to be more relevant than numerical values by which Schuster (1906) and Yule (1927) had calculated the respective 11.125 years and 10.60 years in the past. We revised the theoretical expression in the thesis of Anderson, Shaman, Lindgren, Brillinger, Newbold, Parzen, Kingman, Van Ness and Kenneth, etc. and executed the numerical analysis of period of sunspot numbers investigated now. (auth.)

  13. Period of sunspot numbers is 11. 02653720 years (11 years 9 days 16 hours 18 minutes 0 seconds)

    Energy Technology Data Exchange (ETDEWEB)

    Norita, S [Miyazaki Univ. (Japan). Faculty of Engineering

    1976-09-01

    In the statistical analysis of time series there have been applied usually the stationary stochastic process or the Markov stochastic process and recently there are applied remarkably an autoregressive process, a stochastic difference equation, an autoregressive-moving average process, a moving average process, the Whittaker periodogram, the correlogram, Schuster periodogram, chi-squared periodogram, level crossings, harmonic process, difference method, spectral density and first order vector equation, but in special case it is desirable to apply the nonstationary stocastic process. In this paper we introduce a stationarity into the autoregressive process and then it is the first purpose to compute precisely the period of sunspot numbers. The result up to the eighth places at the decimal point was obtained that its period is 11.02653720 years, that is, 11 years 9 days 16 hours 18 minutes 0 seconds. This is considered to be more relevant than numerical values by which Schuster (1906) and Yule (1927) had calculated the respective 11.125 years and 10.60 years in the past. We revised the theoretical expression in the thesis of Anderson, Shaman, Lindgren, Brillinger, Newbold, Parzen, Kingman, Van Ness and Kenneth, etc. and executed the numerical analysis of period of sunspot numbers investigated now.

  14. North–South Asymmetry in Rieger-type Periodicity during Solar Cycles 19–23

    International Nuclear Information System (INIS)

    Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Oliver, Ramon; Ballester, Jose Luis; Dikpati, Mausumi; McIntosh, Scott W.

    2017-01-01

    Rieger-type periodicity has been detected in different activity indices over many solar cycles. It was recently shown that the periodicity correlates with solar activity having a shorter period during stronger cycles. Solar activity level is generally asymmetric between northern and southern hemispheres, which could suggest the presence of a similar behavior in the Rieger-type periodicity. We analyze the sunspot area/number and the total magnetic flux data for northern and southern hemispheres during solar cycles 19–23, which had remarkable north–south asymmetry. Using wavelet analysis of sunspot area and number during the north-dominated cycles (19–20), we obtained the periodicity of 160–165 days in the stronger northern hemisphere and 180–190 days in the weaker southern hemisphere. On the other hand, south-dominated cycles (21–23) display the periodicity of 155–160 days in the stronger southern hemisphere and 175–188 days in the weaker northern hemisphere. Therefore, the Rieger-type periodicity has the north–south asymmetry in sunspot area/number data during solar cycles with strong hemispheric asymmetry. We suggest that the periodicity is caused by magnetic Rossby waves in the internal dynamo layer. Using the dispersion relation of magnetic Rossby waves and observed Rieger periodicity, we estimated the magnetic field strength in the layer as 45–49 kG in more active hemispheres (north during cycles 19–20 and south during cycles 21–23) and 33–40 kG in weaker hemispheres. The estimated difference in the hemispheric field strength is around 10 kG, which provides a challenge for dynamo models. Total magnetic flux data during cycles 20–23 reveals no clear north–south asymmetry, which needs to be explained in the future.

  15. North–South Asymmetry in Rieger-type Periodicity during Solar Cycles 19–23

    Energy Technology Data Exchange (ETDEWEB)

    Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil [Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia (United States); Oliver, Ramon; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain); Dikpati, Mausumi; McIntosh, Scott W., E-mail: Eka.gurgenashvili.1@iliauni.edu.ge [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2017-08-20

    Rieger-type periodicity has been detected in different activity indices over many solar cycles. It was recently shown that the periodicity correlates with solar activity having a shorter period during stronger cycles. Solar activity level is generally asymmetric between northern and southern hemispheres, which could suggest the presence of a similar behavior in the Rieger-type periodicity. We analyze the sunspot area/number and the total magnetic flux data for northern and southern hemispheres during solar cycles 19–23, which had remarkable north–south asymmetry. Using wavelet analysis of sunspot area and number during the north-dominated cycles (19–20), we obtained the periodicity of 160–165 days in the stronger northern hemisphere and 180–190 days in the weaker southern hemisphere. On the other hand, south-dominated cycles (21–23) display the periodicity of 155–160 days in the stronger southern hemisphere and 175–188 days in the weaker northern hemisphere. Therefore, the Rieger-type periodicity has the north–south asymmetry in sunspot area/number data during solar cycles with strong hemispheric asymmetry. We suggest that the periodicity is caused by magnetic Rossby waves in the internal dynamo layer. Using the dispersion relation of magnetic Rossby waves and observed Rieger periodicity, we estimated the magnetic field strength in the layer as 45–49 kG in more active hemispheres (north during cycles 19–20 and south during cycles 21–23) and 33–40 kG in weaker hemispheres. The estimated difference in the hemispheric field strength is around 10 kG, which provides a challenge for dynamo models. Total magnetic flux data during cycles 20–23 reveals no clear north–south asymmetry, which needs to be explained in the future.

  16. Latitudinal migration of sunspots based on the ESAI database

    Science.gov (United States)

    Zhang, Juan; Li, Fu-Yu; Feng, Wen

    2018-01-01

    The latitudinal migration of sunspots toward the equator, which implies there is propagation of the toroidal magnetic flux wave at the base of the solar convection zone, is one of the crucial observational bases for the solar dynamo to generate a magnetic field by shearing of the pre-existing poloidal magnetic field through differential rotation. The Extended time series of Solar Activity Indices (ESAI) elongated the Greenwich observation record of sunspots by several decades in the past. In this study, ESAI’s yearly mean latitude of sunspots in the northern and southern hemispheres during the years 1854 to 1985 is utilized to statistically test whether hemispherical latitudinal migration of sunspots in a solar cycle is linear or nonlinear. It is found that a quadratic function is statistically significantly better at describing hemispherical latitudinal migration of sunspots in a solar cycle than a linear function. In addition, the latitude migration velocity of sunspots in a solar cycle decreases as the cycle progresses, providing a particular constraint for solar dynamo models. Indeed, the butterfly wing pattern with a faster latitudinal migration rate should present stronger solar activity with a shorter cycle period, and it is located at higher latitudinal position, giving evidence to support the Babcock-Leighton dynamo mechanism.

  17. Solar-cycle period-amplitude relation as evidence of hysteresis of the solar-cycle nonlinear magnetic oscillation and the long-term (55 year) cyclic modulation

    International Nuclear Information System (INIS)

    Yoshimura, H.

    1979-01-01

    A new dynamical model of the solar cycle has predicted that the cycle should have a hysteretic nature: the behavior of each 11 year cycle should depend on previous cycles. In the light of this new understanding of the dynamical mechanism of the solar cycle, Waldmeier's (hypothetical) law was examined as a yet unexplained characteristic of the cycle by studying the observed sunspot frequency curve. Contrary to this hypothetical law, however, it was found that sunspot cycle curves did not form a single-parameter family characterized by the maximum amplitude of the cycle. The evolutionary trajectories in period-amplitude phase space verified the hysteretic nature of the observed cycle and revealed long-term (55 year instead of the previously claimed 80 year) periodic modulations, called here 55 year grand cycles. Each 55 year grand cycle forms a loop in the phase space, and the characteristics of each 11 year cycle depend on its position in the ascending or descending phase of the grand cycle. This new law was analyzed by the nonlinear multiple-period dynamo oscillation model which has predicted the hysteretic nature. The era from cycle 11 to cycle 15 turned out to be an anomalous one characterized by alternating amplitudes for odd and even cycles. Cycles 16--20 seem to constitute one grand cycle. If this is true, cycle 21 would be the beginning of another grand maximum and the model predicts that its duration would be short

  18. On sunspots

    CERN Document Server

    Galilei, Galileo; Reeves, Eileen; Helden, Albert van

    2010-01-01

    Galileo's telescopic discoveries, and especially his observation of sunspots, caused great debate in an age when the heavens were thought to be perfect and unchanging. Christoph Scheiner, a Jesuit mathematician, argued that sunspots were planets or moons crossing in front of the Sun. Galileo, on the other hand, countered that the spots were on or near the surface of the Sun itself, and he supported his position with a series of meticulous observations and mathematical demonstrations that eventually convinced even his rival.  On Sunspots collects the correspondenc

  19. Critical frequencies of the ionospheric F1 and F2 layers during the last four solar cycles: Sunspot group type dependencies

    Science.gov (United States)

    Yiǧit, Erdal; Kilcik, Ali; Elias, Ana Georgina; Dönmez, Burçin; Ozguc, Atila; Yurchshyn, Vasyl; Rozelot, Jean-Pierre

    2018-06-01

    The long term solar activity dependencies of ionospheric F1 and F2 regions' critical frequencies (f0F1 and f0F2) are analyzed for the last four solar cycles (1976-2015). We show that the ionospheric F1 and F2 regions have different solar activity dependencies in terms of the sunspot group (SG) numbers: F1 region critical frequency (f0F1) peaks at the same time with the small SG numbers, while the f0F2 reaches its maximum at the same time with the large SG numbers, especially during the solar cycle 23. The observed differences in the sensitivity of ionospheric critical frequencies to sunspot group (SG) numbers provide a new insight into the solar activity effects on the ionosphere and space weather. While the F1 layer is influenced by the slow solar wind, which is largely associated with small SGs, the ionospheric F2 layer is more sensitive to Coronal Mass Ejections (CMEs) and fast solar winds, which are mainly produced by large SGs and coronal holes. The SG numbers maximize during of peak of the solar cycle and the number of coronal holes peaks during the sunspot declining phase. During solar minimum there are relatively less large SGs, hence reduced CME and flare activity. These results provide a new perspective for assessing how the different regions of the ionosphere respond to space weather effects.

  20. Egeson’s (George’s) transtridecadal weather cycling and sunspots

    Science.gov (United States)

    Halberg, F.; Cornélissen, G.; Bernhardt, K.-H.; Sampson, M.; Schwartzkopff, O.; Sonntag, D.

    2011-01-01

    In the late 19th century, Charles Egeson, a map compiler at the Sydney Observatory, carried out some of the earliest research on climatic cycles, linking them to about 33-year cycles in solar activity, and predicted that a devastating drought would strike Australia at the turn of the 20th century. Eduard Brückner and William J. S. Lockyer, who, like Egeson, found similar cycles, with notable exceptions, are also, like the map compiler, mostly forgotten. But the transtridecadal cycles are important in human physiology, economics and other affairs and are particularly pertinent to ongoing discusions of climate change. Egeson’s publication of daily weather reports preceded those officially recorded. Their publication led to clashes with his superiors and his personal life was marked by run-ins with the law and, possibly, an implied, but not proven, confinement in an insane asylum and premature death. We here track what little is known of Egeson’s life and of his bucking of the conventional scientific wisdom of his time with tragic results. PMID:21547003

  1. On the relation between activity-related frequency shifts and the sunspot distribution over the solar cycle 23

    Directory of Open Access Journals (Sweden)

    Santos Ângela R. G.

    2017-01-01

    Full Text Available The activity-related variations in the solar acoustic frequencies have been known for 30 years. However, the importance of the different contributions is still not well established. With this in mind, we developed an empirical model to estimate the spot-induced frequency shifts, which takes into account the sunspot properties, such as area and latitude. The comparison between the model frequency shifts obtained from the daily sunspot records and those observed suggests that the contribution from a stochastic component to the total frequency shifts is about 30%. The remaining 70% is related to a global, long-term variation. We also propose a new observable to investigate the short-and mid-term variations of the frequency shifts, which is insensitive to the long-term variations contained in the data. On the shortest time scales the variations in the frequency shifts are strongly correlated with the variations in the total area covered by sunspots. However, a significant loss of correlation is still found, which cannot be fully explained by ignoring the invisible side of the Sun when accounting for the total sunspot area. We also verify that the times when the frequency shifts and the sunspot areas do not vary in a similar way tend to coincide with the times of the maximum amplitude of the quasi-biennial variations found in the seismic data.

  2. Visual Circular Analysis of 266 Years of Sunspot Counts.

    Science.gov (United States)

    Buelens, Bart

    2016-06-01

    Sunspots, colder areas that are visible as dark spots on the surface of the Sun, have been observed for centuries. Their number varies with a period of ∼11 years, a phenomenon closely related to the solar activity cycle. Recently, observation records dating back to 1749 have been reassessed, resulting in the release of a time series of sunspot numbers covering 266 years of observations. This series is analyzed using circular analysis to determine the periodicity of the occurrence of solar maxima. The circular analysis is combined with spiral graphs to provide a single visualization, simultaneously showing the periodicity of the series, the degree to which individual cycle lengths deviate from the average period, and differences in levels reached during the different maxima. This type of visualization of cyclic time series with varying cycle lengths in which significant events occur periodically is broadly applicable. It is aimed particularly at science communication, education, and public outreach.

  3. RIEGER-TYPE PERIODICITY DURING SOLAR CYCLES 14–24: ESTIMATION OF DYNAMO MAGNETIC FIELD STRENGTH IN THE SOLAR INTERIOR

    Energy Technology Data Exchange (ETDEWEB)

    Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Ramishvili, Giorgi; Shergelashvili, Bidzina [Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia (United States); Oliver, Ramon; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain); Hanslmeier, Arnold [IGAM, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Poedts, Stefaan, E-mail: teimuraz.zaqarashvili@uni-graz.at [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001, Leuven (Belgium)

    2016-07-20

    Solar activity undergoes a variation over timescales of several months known as Rieger-type periodicity, which usually occurs near maxima of sunspot cycles. An early analysis showed that the periodicity appears only in some cycles and is absent in other cycles. But the appearance/absence during different cycles has not been explained. We performed a wavelet analysis of sunspot data from the Greenwich Royal Observatory and the Royal Observatory of Belgium during cycles 14–24. We found that the Rieger-type periods occur in all cycles, but they are cycle dependent: shorter periods occur during stronger cycles. Our analysis revealed a periodicity of 185–195 days during the weak cycles 14–15 and 24 and a periodicity of 155–165 days during the stronger cycles 16–23. We derived the dispersion relation of the spherical harmonics of the magnetic Rossby waves in the presence of differential rotation and a toroidal magnetic field in the dynamo layer near the base of the convection zone. This showed that the harmonics of fast Rossby waves with m = 1 and n = 4, where m ( n ) indicates the toroidal (poloidal) wavenumbers, perfectly fit with the observed periodicity. The variation of the toroidal field strength from weaker to stronger cycles may lead to the different periods found in those cycles, which explains the observed enigmatic feature of the Rieger-type periodicity. Finally, we used the observed periodicity to estimate the dynamo field strength during cycles 14–24. Our estimations suggest a field strength of ∼40 kG for the stronger cycles and ∼20 kG for the weaker cycles.

  4. The reconciliation of an F-region irregularity model with sunspot-cycle variations in spread-F occurrence

    International Nuclear Information System (INIS)

    Singleton, D.G.

    1974-11-01

    A recently proposed means of combining models of ionospheric F-layer peak electron density and irregularity incremental electron density (ΔN) so as to simulate the global occurrence probability of the frequency spreading component of spread-F is discussed. This procedure is then used to model experimental spread-F occurrence results. It is found possible to readily simulate the sunspot-maximum results, independently of season, with only small adjustments to the amplitudes of the empirical expressions used to ΔN in the several latitude regimes. However, at sunspot minimum and for each season, the ΔN model requires modification in the equatorial and mid-latitude regions of high irregularity incidence, before successful simulations of the spread-F data can be obtained. These modifications, which include a broadening of the equatorial region and a polewards shift to the mid-latitude region with decreasing sunspot number, are discussed in detail. It is concluded that the scintillation data base, from which the original ΔN model derives, is not sufficiently representative with regard to sunspot number and magnetic index. The use of the spread-F adaptation of the ΔN model, as well as its original scintillation version, to rectify these failings of the ΔN model are also discussed. (author)

  5. Empirical mode decomposition and long-range correlation analysis of sunspot time series

    International Nuclear Information System (INIS)

    Zhou, Yu; Leung, Yee

    2010-01-01

    Sunspots, which are the best known and most variable features of the solar surface, affect our planet in many ways. The number of sunspots during a period of time is highly variable and arouses strong research interest. When multifractal detrended fluctuation analysis (MF-DFA) is employed to study the fractal properties and long-range correlation of the sunspot series, some spurious crossover points might appear because of the periodic and quasi-periodic trends in the series. However many cycles of solar activities can be reflected by the sunspot time series. The 11-year cycle is perhaps the most famous cycle of the sunspot activity. These cycles pose problems for the investigation of the scaling behavior of sunspot time series. Using different methods to handle the 11-year cycle generally creates totally different results. Using MF-DFA, Movahed and co-workers employed Fourier truncation to deal with the 11-year cycle and found that the series is long-range anti-correlated with a Hurst exponent, H, of about 0.12. However, Hu and co-workers proposed an adaptive detrending method for the MF-DFA and discovered long-range correlation characterized by H≈0.74. In an attempt to get to the bottom of the problem in the present paper, empirical mode decomposition (EMD), a data-driven adaptive method, is applied to first extract the components with different dominant frequencies. MF-DFA is then employed to study the long-range correlation of the sunspot time series under the influence of these components. On removing the effects of these periods, the natural long-range correlation of the sunspot time series can be revealed. With the removal of the 11-year cycle, a crossover point located at around 60 months is discovered to be a reasonable point separating two different time scale ranges, H≈0.72 and H≈1.49. And on removing all cycles longer than 11 years, we have H≈0.69 and H≈0.28. The three cycle-removing methods—Fourier truncation, adaptive detrending and the

  6. New Realization of Periodic Cycled Separation

    DEFF Research Database (Denmark)

    Toftegard, Bjarne; Clausen, Charlotte H.; Jørgensen, Sten B.

    2016-01-01

    are drained sequentially rather than simultaneously, such that the vapor flow is not interrupted during the liquid drainage. For different ratios of counter-current vapor/liquid flow rates, column efficiencies for periodically cycled columns are shown experimentally to be two times greater than those...

  7. Probability Estimates of Solar Particle Event Doses During a Period of Low Sunspot Number for Thinly-Shielded Spacecraft and Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper (Atwell, et al., 2015), we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the sunspot number (SSN) was less than 30. These SPEs contain Ground Level Events (GLE), sub-GLEs, and sub-sub-GLEs (Tylka and Dietrich, 2009, Tylka and Dietrich, 2008, and Atwell, et al., 2008). GLEs are extremely energetic solar particle events having proton energies extending into the several GeV range and producing secondary particles in the atmosphere, mostly neutrons, observed with ground station neutron monitors. Sub-GLE events are less energetic, extending into the several hundred MeV range, but do not produce secondary atmospheric particles. Sub-sub GLEs are even less energetic with an observable increase in protons at energies greater than 30 MeV, but no observable proton flux above 300 MeV. In this paper, we consider those SPEs that occurred during 1973-2010 when the SSN was greater than 30 but less than 50. In addition, we provide probability estimates of absorbed dose based on mission duration with a 95% confidence level (CL). We also discuss the implications of these data and provide some recommendations that may be useful to spacecraft designers of these smaller spacecraft.

  8. Improvement of the photometric sunspot index and changes of the disk-integrated sunspot contrast with time

    Science.gov (United States)

    Froehlich, Claus; Pap, Judit M.; Hudson, Hugh S.

    1994-06-01

    The photometric sunspot index (PSI) was developed to study the effects of sunspots on solar irradiance. It is calculated from the sunspot data published in the Solar-Geophysical Data catalog. It has been shown that the former PSI models overestimate the effect of dark sunspots on solar irradiance; furthermore results of direct sunspot photometry indicate that the contrast of spots depends on their area. An improved PSI calculation is presented; it takes into account the area dependence of the contrast and calculates `true' daily means for each observation using the differential rotation of the spots. Moreover, the observations are screened for outliers which improves the homogeneity of the data set substantially, at least for the period after December 1981 when NOAA started to report data from a few instead of one to two stations. A detailed description of the method is provided. The correlation between the newly calculated PSI and total solar irradiance is studied for different phases of the solar cycles 21 and 22 using bi-variate spectral analysis. The results can be used as a `calibration' of PSI in terms of gain, the factor by which PSI has to be multiplied to yield the observed irradiance change. The factor changes with time from about 0.6 in 1980 to 1.1 in 1990. This unexpected result cannot be interpreted by a change of the contrast relative to the quiet Sun (as it is normally defined and determined by direct photometry) but rather as a change of the contrast between the spots and their surrounding as seen in total irradiance (integrated over the solar disk). This may partly be explained by a change in the ratio between the areas of the spots and the surrounding faculae.

  9. Sunspots During the Maunder Minimum from Machina Coelestis by Hevelius

    Science.gov (United States)

    Carrasco, V. M. S.; Álvarez, J. Villalba; Vaquero, J. M.

    2015-10-01

    We revisited the sunspot observations published by Johannes Hevelius in his book Machina Coelestis (1679) corresponding to the period of 1653 - 1675 (just in the middle of the Maunder Minimum). We show detailed translations of the original Latin texts describing the sunspot records and provide the general context of these sunspot observations. From this source, we present an estimate of the annual values of the group sunspot number based only on the records that explicitly inform us of the presence or absence of sunspots. Although we obtain very low values of the group sunspot number, in accordance with a grand minimum of solar activity, these values are significantly higher in general than the values provided by Hoyt and Schatten ( Solar Phys. 179, 189, 1998) for the same period.

  10. Application of Avco data analysis and prediction techniques (ADAPT) to prediction of sunspot activity

    Science.gov (United States)

    Hunter, H. E.; Amato, R. A.

    1972-01-01

    The results are presented of the application of Avco Data Analysis and Prediction Techniques (ADAPT) to derivation of new algorithms for the prediction of future sunspot activity. The ADAPT derived algorithms show a factor of 2 to 3 reduction in the expected 2-sigma errors in the estimates of the 81-day running average of the Zurich sunspot numbers. The report presents: (1) the best estimates for sunspot cycles 20 and 21, (2) a comparison of the ADAPT performance with conventional techniques, and (3) specific approaches to further reduction in the errors of estimated sunspot activity and to recovery of earlier sunspot historical data. The ADAPT programs are used both to derive regression algorithm for prediction of the entire 11-year sunspot cycle from the preceding two cycles and to derive extrapolation algorithms for extrapolating a given sunspot cycle based on any available portion of the cycle.

  11. Long-term Modulation of Cosmic Ray Intensity in relation to Sunspot ...

    Indian Academy of Sciences (India)

    it should be more closely connected with cosmic ray modulation than with other solar characteristics (sunspot numbers or coronal emission intensity). The intensity of galactic cosmic rays varies inversely with sunspot numbers, having their maximum intensity at the minimum of the 11-year sunspot cycle (Forbush 1954, 1958) ...

  12. Wings of the butterfly: Sunspot groups for 1826-2015

    Science.gov (United States)

    Leussu, R.; Usoskin, I. G.; Senthamizh Pavai, V.; Diercke, A.; Arlt, R.; Denker, C.; Mursula, K.

    2017-03-01

    The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826-1867) and Spörer (1866-1880). The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30°-45°) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20°-30°) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2°-10°) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer. Digital data for Fig. 1 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A131

  13. On the insignificance of Herschel's sunspot correlation

    Science.gov (United States)

    Love, Jeffrey J.

    2013-08-01

    We examine William Herschel's hypothesis that solar-cycle variation of the Sun's irradiance has a modulating effect on the Earth's climate and that this is, specifically, manifested as an anticorrelation between sunspot number and the market price of wheat. Since Herschel first proposed his hypothesis in 1801, it has been regarded with both interest and skepticism. Recently, reports have been published that either support Herschel's hypothesis or rely on its validity. As a test of Herschel's hypothesis, we seek to reject a null hypothesis of a statistically random correlation between historical sunspot numbers, wheat prices in London and the United States, and wheat farm yields in the United States. We employ binary-correlation, Pearson-correlation, and frequency-domain methods. We test our methods using a historical geomagnetic activity index, well known to be causally correlated with sunspot number. As expected, the measured correlation between sunspot number and geomagnetic activity would be an unlikely realization of random data; the correlation is "statistically significant." On the other hand, measured correlations between sunspot number and wheat price and wheat yield data would be very likely realizations of random data; these correlations are "insignificant." Therefore, Herschel's hypothesis must be regarded with skepticism. We compare and contrast our results with those of other researchers. We discuss procedures for evaluating hypotheses that are formulated from historical data.

  14. Coordination failure caused by sunspots

    DEFF Research Database (Denmark)

    Beugnot, Julie; Gürgüç, Zeynep; Øvlisen, Frederik Roose

    2012-01-01

    on the efficient equilibrium, we consider sunspots as a potential reason for coordination failure. We conduct an experiment with a three player 2x2x2 game in which coordination on the efficient equilibrium is easy and should normally occur. In the control session, we find almost perfect coordination on the payoff......-dominant equilibrium, but in the sunspot treatment, dis-coordination is frequent. Sunspots lead to significant inefficiency, and we conclude that sunspots can indeed cause coordination failure....

  15. Mammalian cycles: internally defined periods and interaction-driven amplitudes

    Directory of Open Access Journals (Sweden)

    LR Ginzburg

    2015-08-01

    Full Text Available The cause of mammalian cycles—the rise and fall of populations over a predictable period of time—has remained controversial since these patterns were first observed over a century ago. In spite of extensive work on observable mammalian cycles, the field has remained divided upon what the true cause is, with a majority of opinions attributing it to either predation or to intra-species mechanisms. Here we unite the eigenperiod hypothesis, which describes an internal, maternal effect-based mechanism to explain the cycles’ periods with a recent generalization explaining the amplitude of snowshoe hare cycles in northwestern North America based on initial predator abundance. By explaining the period and the amplitude of the cycle with separate mechanisms, a unified and consistent view of the causation of cycles is reached. Based on our suggested theory, we forecast the next snowshoe hare cycle (predicted peak in 2016 to be of extraordinarily low amplitude.

  16. ASYMMETRIC SUNSPOT ACTIVITY AND THE SOUTHWARD DISPLACEMENT OF THE HELIOSPHERIC CURRENT SHEET

    International Nuclear Information System (INIS)

    Wang, Y.-M.; Robbrecht, E.

    2011-01-01

    Observations of the interplanetary magnetic field (IMF) have suggested a statistical tendency for the heliospheric current sheet (HCS) to be shifted a few degrees southward of the heliographic equator during the period 1965-2010, particularly in the years near sunspot minimum. Using potential-field source-surface extrapolations and photospheric flux-transport simulations, we demonstrate that this southward displacement follows from Joy's law and the observed hemispheric asymmetry in the sunspot numbers, with activity being stronger in the southern (northern) hemisphere during the declining (rising) phase of cycles 20-23. The hemispheric asymmetry gives rise to an axisymmetric quadrupole field, whose equatorial zone has the sign of the leading-polarity flux in the dominant hemisphere; during the last four cycles, the polarity of the IMF around the equator thus tended to match that of the north polar field both before and after polar field reversal. However, large fluctuations are introduced by the nonaxisymmetric field components, which depend on the longitudinal distribution of sunspot activity in either hemisphere. Consistent with this model, the HCS showed an average northward displacement during cycle 19, when the 'usual' alternation was reversed and the northern hemisphere became far more active than the southern hemisphere during the declining phase of the cycle. We propose a new method for determining the north-south displacement of the HCS from coronal streamer observations.

  17. Sunspot proper motions in active region NOAA 2372 and its flare activity during SMY period of 1980 April 4-13

    International Nuclear Information System (INIS)

    Ambastha, A.; Bhatnagar, A.

    1988-01-01

    Solar Active Region NOAA 2372 was observed extensively by the Solar Maximum Mission (SMM) satellite and several ground-based observatories during 1980 April 4-13 in the Solar Maximum Year. After its birth around April 4, it underwent a rapid growth and produced a reported 84 flares in the course of its disc passage. In this paper, photospheric and chromospheric observations of this active region have been studied together with Marshall Space Flight Center magnetograms and X-ray data from HXIS aboard the SMM satellite. In particular, the relationship of the flare-productivity with sunspot proper motions and emergence of new regions of magnetic flux in the active region from its birth to its disappearance at the W-limb has been discussed. (author). 7 figures, 2 tables, 29 refs

  18. On two populations of sunspot groups

    International Nuclear Information System (INIS)

    Kuklin, G.V.

    1980-01-01

    The principal component method was applied studying the sunspot groups distribution in respect to the maximum area for the individual 11-year cycles 12 to 19 (Lopez Arroyo and Lahulla, 1974) and for the years 1900 to 1964 (Mandrykina, 1974). The existence of two populations of sunspot groups is confirmed. The variations of the importance parameter q, which determines the population shares, in the 80-, 22- and 11-year cycles are considered. The obtained maximal area distributions for populations I and II are approximated by linear combination of logarithmic-normal distributions, the subpopulations Ia, Ib, Ic by the most probable maximum areas of 22, 298 and 90 mvh, respectively, and the subpopulations IIa, IIb, IIc by the most probable maximal areas of 6, 142 and 754 mvh, respectively. The characteristic distinction between populations I and II is apparently the magnetic structure of the groups belonging to them (bipolar and unipolar ones). (author)

  19. Association of Plages with Sunspots: A Multi-Wavelength Study Using Kodaikanal Ca ii K and Greenwich Sunspot Area Data

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, Dipankar, E-mail: sudip@iiap.res.in [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

    2017-02-01

    Plages are the magnetically active chromospheric structures prominently visible in the Ca ii K line (3933.67 Å). A plage may or may not be associated with a sunspot, which is a magnetic structure visible in the solar photosphere. In this study we explore this aspect of association of plages with sunspots using the newly digitized Kodaikanal Ca ii K plage data and the Greenwich sunspot area data. Instead of using the plage index or fractional plage area and its comparison with the sunspot number, we use, to our knowledge for the first time, the individual plage areas and compare them with the sunspot area time series. Our analysis shows that these two structures, formed in two different layers, are highly correlated with each other on a timescale comparable to the solar cycle. The area and the latitudinal distributions of plages are also similar to those of sunspots. Different area thresholdings on the “butterfly diagram” reveal that plages of area ≥4 arcmin{sup 2} are mostly associated with a sunspot in the photosphere. Apart from this, we found that the cyclic properties change when plages of different sizes are considered separately. These results may help us to better understand the generation and evolution of the magnetic structures in different layers of the solar atmosphere.

  20. Inherent characteristics of sawtooth cycles can explain different glacial periodicities

    NARCIS (Netherlands)

    Omta, A.W.; Kooi, B.W.; van Voorn, G.A.K.; Rickaby, R.E.M; Follows, M.J.

    2016-01-01

    At the Mid-Pleistocene Transition about 1 Ma, the dominant periodicity of the glacial-interglacial cycles shifted from ~40 to ~100 kyr. Here, we use a previously developed mathematical model to investigate the possible dynamical origin of these different periodicities. The model has two variables,

  1. Inherent characteristics of sawtooth cycles can explain different glacial periodicities

    NARCIS (Netherlands)

    Omta, Anne Willem; Kooi, Bob W.; Voorn, van G.A.K.; Rickaby, Rosalind E.M.; Follows, Michael J.

    2016-01-01

    At the Mid-Pleistocene Transition about 1 Ma, the dominant periodicity of the glacial-interglacial cycles shifted from ~40 to ~100 kyr. Here, we use a previously developed mathematical model to investigate the possible dynamical origin of these different periodicities. The model has two

  2. Photometric measurements of solar irradiance variations due to sunspots

    International Nuclear Information System (INIS)

    Chapman, G.A.; Herzog, A.D.; Laico, D.E.; Lawrence, J.K.; Templer, M.S.

    1989-01-01

    A photometric telescope constructed to obtain photometric sunspot areas and deficits on a daily basis is described. Data from this Cartesian full disk telescope (CFDT) are analyzed with attention given to the period between June 4 and June 17, 1985 because of the availability of overlapping sunspot area and irradiance deficit data from high-resolution digital spectroheliograms made with the San Fernando Observatory 28 cm vacuum solar telescope and spectroheliograph. The CFDT sunspot deficits suggest a substantial irradiance contribution from faculae and active region plage. 23 refs

  3. A Standard Law for the Equatorward Drift of the Sunspot Zones

    Science.gov (United States)

    Hathaway, David H.

    2012-01-01

    The latitudinal location of the sunspot zones in each hemisphere is determined by calculating the centroid position of sunspot areas for each solar rotation from May 1874 to June 2012. When these centroid positions are plotted and analyzed as functions of time from each sunspot cycle maximum there appears to be systematic differences in the positions and equatorward drift rates as a function of sunspot cycle amplitude. If, instead, these centroid positions are plotted and analyzed as functions of time from each sunspot cycle minimum then most of the differences in the positions and equatorward drift rates disappear. The differences that remain disappear entirely if curve fitting is used to determine the starting times (which vary by as much as 8 months from the times of minima). The sunspot zone latitudes and equatorward drift measured relative to this starting time follow a standard path for all cycles with no dependence upon cycle strength or hemispheric dominance. Although Cycle 23 was peculiar in its length and the strength of the polar fields it produced, it too shows no significant variation from this standard. This standard law, and the lack of variation with sunspot cycle characteristics, is consistent with Dynamo Wave mechanisms but not consistent with current Flux Transport Dynamo models for the equatorward drift of the sunspot zones.

  4. INTERFERENCE FRINGES OF SOLAR ACOUSTIC WAVES AROUND SUNSPOTS

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Dean-Yi; Zhao Hui; Yang, Ming-Hsu; Liang, Zhi-Chao, E-mail: chou@phys.nthu.edu.tw [Physics Department, National Tsing Hua University, Hsinchu, Taiwan (China)

    2012-10-20

    Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

  5. Identification of possible intense historical geomagnetic storms using combined sunspot and auroral observations from East Asia

    Directory of Open Access Journals (Sweden)

    D. M. Willis

    2005-03-01

    Full Text Available Comprehensive catalogues of ancient sunspot and auroral observations from East Asia are used to identify possible intense historical geomagnetic storms in the interval 210 BC-AD 1918. There are about 270 entries in the sunspot catalogue and about 1150 entries in the auroral catalogue. Special databases have been constructed in which the scientific information in these two catalogues is placed in specified fields. For the purposes of this study, an historical geomagnetic storm is defined in terms of an auroral observation that is apparently associated with a particular sunspot observation, in the sense that the auroral observation occurred within several days of the sunspot observation. More precisely, a selection criterion is formulated for the automatic identification of such geomagnetic storms, using the oriental records stored in the sunspot and auroral databases. The selection criterion is based on specific assumptions about the duration of sunspot visibility with the unaided eye, the likely range of heliographic longitudes of an energetic solar feature, and the likely range of transit times for ejected solar plasma to travel from the Sun to the Earth. This selection criterion results in the identification of nineteen putative historical geomagnetic storms, although two of these storms are spurious in the sense that there are two examples of a single sunspot observation being associated with two different auroral observations separated by more than half a (synodic solar rotation period. The literary and scientific reliabilities of the East Asian sunspot and auroral records that define the nineteen historical geomagnetic storms are discussed in detail in a set of appendices. A possible time sequence of events is presented for each geomagnetic storm, including possible dates for both the central meridian passage of the sunspot and the occurrence of the energetic solar feature, as well as likely transit times for the ejected solar plasma

  6. Photoelectric observations of propagating sunspot oscillations

    International Nuclear Information System (INIS)

    Lites, B.W.; White, O.R.; Packman, D.

    1982-01-01

    The Sacramento Park Observatory Vacuum Tower Telescope and diode array were used to make repeated intensity and velocity images of a large, isolated sunspot in both a chromospheric (lambda8542 Ca II) and a photospheric (lambda5576 Fe I) line. The movie of the digital data for the chromospheric line shows clearly a relationship between the propagating umbral disturbances and the running penumbral waves. The velocities for transverse propagating of the umbral and penumbral disturbances are 60--70 km s -1 and 20--35 km s -1 , respectively. Power spectra of the oscillations show a sharp peak at a period of about 170 s in both the velocity and intensity signals. The rms velocity fluctuation of this power peak is 0.26 km s -1 . The oscillations at any given point in the sunspot are very regular, and the phase relationship between the velocity and intensity of the chromospheric oscillations is radically different than that for the quiet Sun. Our preliminary interpretation of the phase relationship involves acoustic waves with wave vector directed downwards along the magnetic field lines; however, this interpretation relies on assumptions involved in the data reduction scheme. The mechanical energy flux carried by the observed umbral disturbances does not appear to be a significant contributor to the overall energy budget of the sunspot or the surrounding active region

  7. Oscillations and Waves in Sunspots

    Directory of Open Access Journals (Sweden)

    Elena Khomenko

    2015-11-01

    Full Text Available A magnetic field modifies the properties of waves in a complex way. Significant advances have been made recently in our understanding of the physics of sunspot waves with the help of high-resolution observations, analytical theories, as well as numerical simulations. We review the current ideas in the field, providing the most coherent picture of sunspot oscillations as by present understanding.

  8. LOOKING FOR GRANULATION AND PERIODICITY IMPRINTS IN THE SUNSPOT TIME SERIES

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Ilídio [Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Silva, Hugo G., E-mail: ilidio.lopes@tecnico.ulisboa.pt, E-mail: hgsilva@uevora.pt [Departamento de Física, ECT, Instituto de Ciências da Terra, Universidade de Évora, Rua Romão Ramalho 59, 7002-554 Évora (Portugal)

    2015-05-10

    The sunspot activity is the end result of the cyclic destruction and regeneration of magnetic fields by the dynamo action. We propose a new method to analyze the daily sunspot areas data recorded since 1874. By computing the power spectral density of daily data series using the Mexican hat wavelet, we found a power spectrum with a well-defined shape, characterized by three features. The first term is the 22 yr solar magnetic cycle, estimated in our work to be 18.43 yr. The second term is related to the daily volatility of sunspots. This term is most likely produced by the turbulent motions linked to the solar granulation. The last term corresponds to a periodic source associated with the solar magnetic activity, for which the maximum power spectral density occurs at 22.67 days. This value is part of the 22–27 day periodicity region that shows an above-average intensity in the power spectra. The origin of this 22.67 day periodic process is not clearly identified, and there is a possibility that it can be produced by convective flows inside the star. The study clearly shows a north–south asymmetry. The 18.43 yr periodical source is correlated between the two hemispheres, but the 22.67 day one is not correlated. It is shown that toward the large timescales an excess occurs in the northern hemisphere, especially near the previous two periodic sources. To further investigate the 22.67 day periodicity, we made a Lomb–Scargle spectral analysis. The study suggests that this periodicity is distinct from others found nearby.

  9. Occurrences of flares with type II and IV radio events in interacting sunspot groups in the course of revolutions

    International Nuclear Information System (INIS)

    Klimes, J.; Krivsky, L.

    1984-01-01

    Using data from 11-year solar cycle No. 20, it was found that flares with type II radio bursts are more than twice as frequent and flares with type IV bursts nearly twice as frequent in sunspot groups which developed close to each other or which merged in the course of revolutions than in isolated sunspot groups. With both types the occurrence of these flares is concentrated in the revolution of the so-called sunspot group interaction (their approximation, merging). (author)

  10. The magnetic nature of umbra-penumbra boundary in sunspots

    Science.gov (United States)

    Jurčák, J.; Rezaei, R.; González, N. Bello; Schlichenmaier, R.; Vomlel, J.

    2018-03-01

    Context. Sunspots are the longest-known manifestation of solar activity, and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penumbrae, the two fundamental sunspot regions, has hitherto been solely defined by an intensity threshold. Aim. Here, we aim at studying the magnetic nature of umbra-penumbra boundaries in sunspots of different sizes, morphologies, evolutionary stages, and phases of the solar cycle. Methods: We used a sample of 88 scans of the Hinode/SOT spectropolarimeter to infer the magnetic field properties in at the umbral boundaries. We defined these umbra-penumbra boundaries by an intensity threshold and performed a statistical analysis of the magnetic field properties on these boundaries. Results: We statistically prove that the umbra-penumbra boundary in stable sunspots is characterised by an invariant value of the vertical magnetic field component: the vertical component of the magnetic field strength does not depend on the umbra size, its morphology, and phase of the solar cycle. With the statistical Bayesian inference, we find that the strength of the vertical magnetic field component is, with a likelihood of 99%, in the range of 1849-1885 G with the most probable value of 1867 G. In contrast, the magnetic field strength and inclination averaged along individual boundaries are found to be dependent on the umbral size: the larger the umbra, the stronger and more horizontal the magnetic field at its boundary. Conclusions: The umbra and penumbra of sunspots are separated by a boundary that has hitherto been defined by an intensity threshold. We now unveil the empirical law of the magnetic nature of the umbra-penumbra boundary in stable sunspots: it is an invariant vertical component of the magnetic field.

  11. Is sunspot activity a factor in influenza pandemics?

    Science.gov (United States)

    Qu, Jiangwen

    2016-09-01

    The 2009 AH1N1 pandemic became a global health concern, although fortunately, its worst anticipated effects were not realised. While the origins of such outbreaks remain poorly understood, it is very important to identify the precipitating factors in their emergence so that future pandemics can be detected as quickly as possible. Methords: Descriptive epidemiology was used to analyse the association between influenza pandemics and possible pandemics and relative number of sunspots. Non-conditional logistic regression was performed to analyse the statistical association between sunspot extremes and influenza pandemics to within plus or minus 1 year. Almost all recorded influenza/possible pandemics have occurred in time frames corresponding to sunspot extremes, or +/- 1 year within such extremes. These periods were identified as important risk factors in both possible and confirmed influenza pandemics (odds ratio: 3.87; 95% confidence interval: 1.08 to 13.85). Extremes of sunspot activity to within plus or minus 1 year may precipitate influenza pandemics. Mechanisms of epidemic initiation and early spread are discussed including primary causation by externally derived viral variants (from space via cometary dust). Efforts to construct a comprehensive early warning system for potential influenza and other viral pandemics that include analysis of sunspot activity and stratospheric sampling for viral variants should be supported. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Empirical solar/stellar cycle simulations

    Directory of Open Access Journals (Sweden)

    Santos Ângela R. G.

    2015-01-01

    Full Text Available As a result of the magnetic cycle, the properties of the solar oscillations vary periodically. With the recent discovery of manifestations of activity cycles in the seismic data of other stars, the understanding of the different contributions to such variations becomes even more important. With this in mind, we built an empirical parameterised model able to reproduce the properties of the sunspot cycle. The resulting simulations can be used to estimate the magnetic-induced frequency shifts.

  13. Sunspot Equilibria in a Production Economy: Do Rational Animal Spirits Cause Overproduction?

    OpenAIRE

    Kajii, Atsushi

    2008-01-01

    We study a standard two period economy with one nominal bond and one firm. The input of the firm is done in the first period and financed with the nominal bond, and its profits are distributed to the shareholders in the second period. We show that a sunspot equilibrium exists around each efficient equilibrium. The interest rate is lower than optimal and there is over production in sunspot equilibria, under some conditions. But a sunspot equilibrium does not exist if the profit share can be tr...

  14. Aurorae, sunspots and weather, mainly since A.D. 1200

    International Nuclear Information System (INIS)

    Schove, D.J.

    1981-01-01

    Auroral records recieved for the Spectrum of Time project were used in 1955 to estimate sunspot activity and the dates maxima and minima back to 649 B.C. An additional set of rules has been developed and has made possible further improvements utilizing the separate auroral maxima associated with flares and coronal holes on the sun. A further set can now be given. 1) The time between sunspot maxima depends especially on the ratio of the amplitudes: the time between minima is high if the next cycle is very weak and low when the two consecutive cycles are both strong. 2) The time of rise is usually dependent on the strength of the next maxima, and the time of fall is low when a moderate cycle is followed by a strong one. (orig./WL)

  15. Application of the Markov chain approximation to the sunspot observations

    International Nuclear Information System (INIS)

    Onal, M.

    1988-01-01

    The positions of the 13,588 sunspot groups observed during the cycle of 1950-1960 at the Istanbul University Observatory have been corrected for the effect of differential rotation. The evolution probability of a sunspot group to the other one in the same region have been determined. By using the Markov chain approximation, the types of these groups and their transition probabilities during the following activity cycle (1950-1960), and the concentration of active regions during 1950-1960 have been estimated. The transition probabilities from the observations of the activity cycle 1960-1970 have been compared with the predicted transition probabilities and a good correlation has been noted. 5 refs.; 2 tabs

  16. RE-EXAMINING SUNSPOT TILT ANGLE TO INCLUDE ANTI-HALE STATISTICS

    International Nuclear Information System (INIS)

    McClintock, B. H.; Norton, A. A.; Li, J.

    2014-01-01

    Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data provided by Li and Ulrich that determined sunspot magnetic tilt angle using Mount Wilson magnetograms from 1974-2012. The magnetograms allowed for BMR tilt angles that were anti-Hale in configuration, so tilt values ranged from 0 to 360° rather than the more common ±90°. We explore the visual representation of magnetic tilt angles on a traditional butterfly diagram by plotting the mean area-weighted latitude of umbral activity in each bipolar sunspot group, including tilt information. The large scatter of tilt angles over the course of a single cycle and hemisphere prevents Joy's law from being visually identified in the tilt-butterfly diagram without further binning. The average latitude of anti-Hale regions does not differ from the average latitude of all regions in both hemispheres. The distribution of anti-Hale sunspot tilt angles are broadly distributed between 0 and 360° with a weak preference for east-west alignment 180° from their expected Joy's law angle. The anti-Hale sunspots display a log-normal size distribution similar to that of all sunspots, indicating no preferred size for anti-Hale sunspots. We report that 8.4% ± 0.8% of all bipolar sunspot regions are misclassified as Hale in traditional catalogs. This percentage is slightly higher for groups within 5° of the equator due to the misalignment of the magnetic and heliographic equators

  17. RE-EXAMINING SUNSPOT TILT ANGLE TO INCLUDE ANTI-HALE STATISTICS

    Energy Technology Data Exchange (ETDEWEB)

    McClintock, B. H. [University of Southern Queensland, Toowoomba, 4350 (Australia); Norton, A. A. [HEPL, Stanford University, Palo Alto, CA 94305 (United States); Li, J., E-mail: u1049686@umail.usq.edu.au, E-mail: aanorton@stanford.edu, E-mail: jli@igpp.ucla.edu [Department of Earth, Planetary, and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095 (United States)

    2014-12-20

    Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data provided by Li and Ulrich that determined sunspot magnetic tilt angle using Mount Wilson magnetograms from 1974-2012. The magnetograms allowed for BMR tilt angles that were anti-Hale in configuration, so tilt values ranged from 0 to 360° rather than the more common ±90°. We explore the visual representation of magnetic tilt angles on a traditional butterfly diagram by plotting the mean area-weighted latitude of umbral activity in each bipolar sunspot group, including tilt information. The large scatter of tilt angles over the course of a single cycle and hemisphere prevents Joy's law from being visually identified in the tilt-butterfly diagram without further binning. The average latitude of anti-Hale regions does not differ from the average latitude of all regions in both hemispheres. The distribution of anti-Hale sunspot tilt angles are broadly distributed between 0 and 360° with a weak preference for east-west alignment 180° from their expected Joy's law angle. The anti-Hale sunspots display a log-normal size distribution similar to that of all sunspots, indicating no preferred size for anti-Hale sunspots. We report that 8.4% ± 0.8% of all bipolar sunspot regions are misclassified as Hale in traditional catalogs. This percentage is slightly higher for groups within 5° of the equator due to the misalignment of the magnetic and heliographic equators.

  18. Periodic Variation of the North-South Asymmetry of Solar Activity ...

    Indian Academy of Sciences (India)

    Abstract. We report here a study of various solar activity phenomena occurring in both north and south hemispheres of the Sun during solar cycles 8-23. In the study we have used sunspot data for the period 1832—. 1976, flare index data for the period 1936-1993, Hα flare data 1993-1998 and solar active prominences data ...

  19. CORRELATION BETWEEN THE 22-YEAR SOLAR MAGNETIC CYCLE AND THE 22-YEAR QUASICYCLE IN THE EARTH'S ATMOSPHERIC TEMPERATURE

    International Nuclear Information System (INIS)

    Qu Weizheng; Zhao Jinping; Huang Fei; Deng Shenggui

    2012-01-01

    According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

  20. Historical evidence concerning the Sun: interpretation of sunspot records during the telescopic and pretelescopic eras

    International Nuclear Information System (INIS)

    Stephenson, F.R.

    1990-01-01

    The value of sunspot observations in investigating solar activity trends - mainly on the centennial to millennial timescale - is considered in some detail. It is shown that although observations made since the mid-eighteenth century are in general very reliable indicators of solar activity, older data are of dubious quality and utility. The sunspot record in both the pretelescopic and early telescopic periods appears to be confused by serious data artefacts. (author)

  1. Sunspot Light Walls Suppressed by Nearby Brightenings

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuhong; Zhang, Jun; Hou, Yijun; Li, Xiaohong [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Erdélyi, Robertus [Solar Physics and Space Plasma Research Centre, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Yan, Limei, E-mail: shuhongyang@nao.cas.cn [Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

    2017-07-01

    Light walls, as ensembles of oscillating bright structures rooted in sunspot light bridges, have not been well studied, although they are important for understanding sunspot properties. Using the Interface Region Imaging Spectrograph and Solar Dynamics Observatory observations, here we study the evolution of two oscillating light walls each within its own active region (AR). The emission of each light wall decays greatly after the appearance of adjacent brightenings. For the first light wall, rooted within AR 12565, the average height, amplitude, and oscillation period significantly decrease from 3.5 Mm, 1.7 Mm, and 8.5 minutes to 1.6 Mm, 0.4 Mm, and 3.0 minutes, respectively. For the second light wall, rooted within AR 12597, the mean height, amplitude, and oscillation period of the light wall decrease from 2.1 Mm, 0.5 Mm, and 3.0 minutes to 1.5 Mm, 0.2 Mm, and 2.1 minutes, respectively. Particularly, a part of the second light wall even becomes invisible after the influence of a nearby brightening. These results reveal that the light walls are suppressed by nearby brightenings. Considering the complex magnetic topology in light bridges, we conjecture that the fading of light walls may be caused by a drop in the magnetic pressure, where the flux is canceled by magnetic reconnection at the site of the nearby brightening. Another hypothesis is that the wall fading is due to the suppression of driver source ( p -mode oscillation), resulting from the nearby avalanche of downward particles along reconnected brightening loops.

  2. LONG-TERM MEASUREMENTS OF SUNSPOT MAGNETIC TILT ANGLES

    Energy Technology Data Exchange (ETDEWEB)

    Li Jing [Department of Earth and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095-1567 (United States); Ulrich, Roger K., E-mail: jli@igpp.ucla.edu [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095-1567 (United States)

    2012-10-20

    Tilt angles of close to 30,600 sunspots are determined using Mount Wilson daily averaged magnetograms taken from 1974 to 2012, and SOHO/MDI magnetograms taken from 1996 to 2010. Within a cycle, more than 90% of sunspots have a normal polarity alignment along the east-west direction following Hale's law. The median tilts increase with increasing latitude (Joy's law) at a rate of {approx}0.{sup 0}5 per degree of latitude. Tilt angles of spots appear largely invariant with respect to time at a given latitude, but they decrease by {approx}0.{sup 0}9 per year on average, a trend that largely reflects Joy's law following the butterfly diagram. We find an asymmetry between the hemispheres in the mean tilt angles. On average, the tilts are greater in the Southern than in the Northern Hemisphere for all latitude zones, and the differences increase with increasing latitude.

  3. HELIOSEISMOLOGY OF A REALISTIC MAGNETOCONVECTIVE SUNSPOT SIMULATION

    International Nuclear Information System (INIS)

    Braun, D. C.; Birch, A. C.; Rempel, M.; Duvall, T. L. Jr.

    2012-01-01

    We compare helioseismic travel-time shifts measured from a realistic magnetoconvective sunspot simulation using both helioseismic holography and time-distance helioseismology, and measured from real sunspots observed with the Helioseismic and Magnetic Imager instrument on board the Solar Dynamics Observatory and the Michelson Doppler Imager instrument on board the Solar and Heliospheric Observatory. We find remarkable similarities in the travel-time shifts measured between the methodologies applied and between the simulated and real sunspots. Forward modeling of the travel-time shifts using either Born or ray approximation kernels and the sound-speed perturbations present in the simulation indicates major disagreements with the measured travel-time shifts. These findings do not substantially change with the application of a correction for the reduction of wave amplitudes in the simulated and real sunspots. Overall, our findings demonstrate the need for new methods for inferring the subsurface structure of sunspots through helioseismic inversions.

  4. CORRELATION BETWEEN THE 22-YEAR SOLAR MAGNETIC CYCLE AND THE 22-YEAR QUASICYCLE IN THE EARTH'S ATMOSPHERIC TEMPERATURE

    Energy Technology Data Exchange (ETDEWEB)

    Qu Weizheng; Zhao Jinping; Huang Fei; Deng Shenggui, E-mail: quweizhe@ouc.edu.cn [College of Environment Oceanography, Ocean University of China, Qingdao 266100 (China)

    2012-07-15

    According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

  5. Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

    Science.gov (United States)

    Nariai, Yukiko; Hayashi, Saki; Morita, Satoru; Umemura, Yoshitaka; Tainaka, Kei-ichi; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2011-04-06

    Periodical cicadas (Magicicada spp.) in the USA are divided into three species groups (-decim, -cassini, -decula) of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect) could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods") with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

  6. Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

    Directory of Open Access Journals (Sweden)

    Yukiko Nariai

    2011-04-01

    Full Text Available Periodical cicadas (Magicicada spp. in the USA are divided into three species groups (-decim, -cassini, -decula of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods" with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

  7. Allee effect in the selection for prime-numbered cycles in periodical cicadas.

    Science.gov (United States)

    Tanaka, Yumi; Yoshimura, Jin; Simon, Chris; Cooley, John R; Tainaka, Kei-ichi

    2009-06-02

    Periodical cicadas are well known for their prime-numbered life cycles (17 and 13 years) and their mass periodical emergences. The origination and persistence of prime-numbered cycles are explained by the hybridization hypothesis on the basis of their lower likelihood of hybridization with other cycles. Recently, we showed by using an integer-based numerical model that prime-numbered cycles are indeed selected for among 10- to 20-year cycles. Here, we develop a real-number-based model to investigate the factors affecting the selection of prime-numbered cycles. We include an Allee effect in our model, such that a critical population size is set as an extinction threshold. We compare the real-number models with and without the Allee effect. The results show that in the presence of an Allee effect, prime-numbered life cycles are most likely to persist and to be selected under a wide range of extinction thresholds.

  8. DYNAMICS IN SUNSPOT UMBRA AS SEEN IN NEW SOLAR TELESCOPE AND INTERFACE REGION IMAGING SPECTROGRAPH DATA

    Energy Technology Data Exchange (ETDEWEB)

    Yurchyshyn, V.; Abramenko, V. [Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States); Kilcik, A. [Department of Space Science and Technologies, Akdeniz University, 07058 Antalya (Turkey)

    2015-01-10

    We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST) for the main sunspot in NOAA AR 11836. We report that the difference between the shock arrival times as measured by the Mg II k 2796.35 Å and Si IV 1393.76 Å line formation levels changes during the observed period, and peak-to-peak delays may range from 40 s to zero. The intensity of chromospheric shocks also displays long-term (about 20 min) variations. NST's high spatial resolution Hα data allowed us to conclude that, in this sunspot, umbral flashes (UFs) appeared in the form of narrow bright lanes stretched along the light bridges and around clusters of umbral bright points. The time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and transition region data appears bright above the locations of light bridges and the areas where the dark umbra is dotted with clusters of umbral dots. Co-spatial and co-temporal data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory showed that the same locations were associated with bright footpoints of coronal loops suggesting that the light bridges may play an important role in heating the coronal sunspot loops. Finally, the power spectra analysis showed that the intensity of chromospheric and transition region oscillations significantly vary across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

  9. Sun in the Epoch ``LOWERED'' Solar Activity: the Comparative Analysis of the Current 24 Solar Cycle and Past Authentic Low Cycles

    Science.gov (United States)

    Vitaly, Ishkov

    A reliable series of the relative numbers of sunspots (14 solar cycles ‒ 165 years) it leads to the only scenario of solar activity cycles - to the alternation of epochs of “increased” (18 ‒ 22 cycles of solar activity) and “lowered” (12 ‒ 16 and 24 ‒ ...) solar activity with the periods of solar magnetic field reconstruction in solar zone of the sunspots formation (11, 12, 23) from one epoch to another. The regime of the produce of magnetic field significantly changes in these periods, providing to the subsequent 5 cycles the stable conditions of solar activity. Space solar research made it possible to sufficiently fully investigate characteristics and parameters of the solar cycles for the epoch of “increased” (20 ‒ 22 cycles) solar activity and period of the reconstruction (22 ‒ 23 cycles) to the epoch of “lowered” solar activity (24 ‒ ... cycles). In this scenario 24 solar cycle is the first solar cycle of the second epoch of “lowered” solar activity. Therefore his development and characteristics roughly must be described in the context of the low solar cycles development (12, 14, and 16). In the current solar cycle the sunspot-forming activity is lowered, the average areas of the sunspot groups correspond to values for epoch of “lowered “solar activity, average magnetic field in the umbra of sunspots was reduced approximately to 700 gauss, and for this time was observed only 4 very large sunspot groups (≥1500 mvh). Flare activity substantially was lowered: for the time of the current solar cycle development it was occurrence of M-class flares M - 368, class X - 32, from which only 2 solar flares of class X> 5. Solar proton events are observed predominantly small intensity; but only 5 from them were the intensity of ≥100 pfu (S2) and 4 - ≥1000 pfu (S3). The first five years of the 24 cycle evolution confirm this assumption and the possibility to give the qualitative forecast of his evolution and development of the

  10. The sunspot databases of the Debrecen Observatory

    Science.gov (United States)

    Baranyi, Tünde; Gyori, Lajos; Ludmány, András

    2015-08-01

    We present the sunspot data bases and online tools available in the Debrecen Heliophysical Observatory: the DPD (Debrecen Photoheliographic Data, 1974 -), the SDD (SOHO/MDI-Debrecen Data, 1996-2010), the HMIDD (SDO/HMI-Debrecen Data, HMIDD, 2010-), the revised version of Greenwich Photoheliographic Data (GPR, 1874-1976) presented together with the Hungarian Historical Solar Drawings (HHSD, 1872-1919). These are the most detailed and reliable documentations of the sunspot activity in the relevant time intervals. They are very useful for studying sunspot group evolution on various time scales from hours to weeks. Time-dependent differences between the available long-term sunspot databases are investigated and cross-calibration factors are determined between them. This work has received funding from the European Community's Seventh Framework Programme (FP7/2012-2015) under grant agreement No. 284461 (eHEROES).

  11. Self-affinity and nonextensivity of sunspots

    International Nuclear Information System (INIS)

    Moret, M.A.

    2014-01-01

    In this paper we study the time series of sunspots by using two different approaches, analyzing its self-affine behavior and studying its distribution. The long-range correlation exponent α has been calculated via Detrended Fluctuation Analysis and the power law vanishes to values greater than 11 years. On the other hand, the distribution of the sunspots obeys a q-exponential decay that suggests a non-extensive behavior. This observed characteristic seems to take an alternative interpretation of the sunspots dynamics. The present findings suggest us to propose a dynamic model of sunspots formation based on a nonlinear Fokker–Planck equation. Therefore its dynamic process follows the generalized thermostatistical formalism.

  12. Featured Image: Bright Dots in a Sunspot

    Science.gov (United States)

    Kohler, Susanna

    2018-03-01

    This image of a sunspot, located in in NOAA AR 12227, was captured in December 2014 by the 0.5-meter Solar Optical Telescope on board the Hinode spacecraft. This image was processed by a team of scientists led by Rahul Yadav (Udaipur Solar Observatory, Physical Research Laboratory Dewali, India) in order to examine the properties of umbral dots: transient, bright features observed in the umbral region (the central, darkest part) of a sunspot. By exploring these dots, Yadav and collaborators learned how their properties relate to the large-scale properties of the sunspots in which they form for instance, how do the number, intensities, or filling factors of dots relate to the size of a sunspots umbra? To find out more about the authors results, check out the article below.Sunspot in NOAA AR 11921. Left: umbralpenumbral boundary. Center: the isolated umbra from the sunspot. Right: The umbra with locations of umbral dots indicated by yellow plus signs. [Adapted from Yadav et al. 2018]CitationRahul Yadav et al 2018 ApJ 855 8. doi:10.3847/1538-4357/aaaeba

  13. NONLINEAR PREDICTION OF SOLAR CYCLE 24

    International Nuclear Information System (INIS)

    Kilcik, A.; Anderson, C. N. K.; Ye, H.; Sugihara, G.; Rozelot, J. P.; Ozguc, A.

    2009-01-01

    Sunspot activity is highly variable and challenging to forecast. Yet forecasts are important, since peak activity has profound effects on major geophysical phenomena including space weather (satellite drag, telecommunications outages) and has even been correlated speculatively with changes in global weather patterns. This paper investigates trends in sunspot activity, using new techniques for decadal-scale prediction of the present solar cycle (cycle 24). First, Hurst exponent H analysis is used to investigate the autocorrelation structure of the putative dynamics; then the Sugihara-May algorithm is used to predict the ascension time and the maximum intensity of the current sunspot cycle. Here we report H = 0.86 for the complete sunspot number data set (1700-2007) and H = 0.88 for the reliable sunspot data set (1848-2007). Using the Sugihara-May algorithm analysis, we forecast that cycle 24 will reach its maximum in 2012 December at approximately 87 sunspot units.

  14. Magnetic cycles and rotation periods of late-type stars from photometric time series

    Science.gov (United States)

    Suárez Mascareño, A.; Rebolo, R.; González Hernández, J. I.

    2016-10-01

    Aims: We investigate the photometric modulation induced by magnetic activity cycles and study the relationship between rotation period and activity cycle(s) in late-type (FGKM) stars. Methods: We analysed light curves, spanning up to nine years, of 125 nearby stars provided by the All Sky Automated Survey (ASAS). The sample is mainly composed of low-activity, main-sequence late-A to mid-M-type stars. We performed a search for short (days) and long-term (years) periodic variations in the photometry. We modelled the light curves with combinations of sinusoids to measure the properties of these periodic signals. To provide a better statistical interpretation of our results, we complement our new results with results from previous similar works. Results: We have been able to measure long-term photometric cycles of 47 stars, out of which 39 have been derived with false alarm probabilities (FAP) of less than 0.1 per cent. Rotational modulation was also detected and rotational periods were measured in 36 stars. For 28 stars we have simultaneous measurements of activity cycles and rotational periods, 17 of which are M-type stars. We measured both photometric amplitudes and periods from sinusoidal fits. The measured cycle periods range from 2 to 14 yr with photometric amplitudes in the range of 5-20 mmag. We found that the distribution of cycle lengths for the different spectral types is similar, as the mean cycle is 9.5 yr for F-type stars, 6.7 yr for G-type stars, 8.5 yr for K-type stars, 6.0 yr for early M-type stars, and 7.1 yr for mid-M-type stars. On the other hand, the distribution of rotation periods is completely different, trending to longer periods for later type stars, from a mean rotation of 8.6 days for F-type stars to 85.4 days in mid-M-type stars. The amplitudes induced by magnetic cycles and rotation show a clear correlation. A trend of photometric amplitudes with rotation period is also outlined in the data. The amplitudes of the photometric variability

  15. Cdk1 activity acts as a quantitative platform for coordinating cell cycle progression with periodic transcription

    Science.gov (United States)

    Banyai, Gabor; Baïdi, Feriel; Coudreuse, Damien; Szilagyi, Zsolt

    2016-01-01

    Cell proliferation is regulated by cyclin-dependent kinases (Cdks) and requires the periodic expression of particular gene clusters in different cell cycle phases. However, the interplay between the networks that generate these transcriptional oscillations and the core cell cycle machinery remains largely unexplored. In this work, we use a synthetic regulable Cdk1 module to demonstrate that periodic expression is governed by quantitative changes in Cdk1 activity, with different clusters directly responding to specific activity levels. We further establish that cell cycle events neither participate in nor interfere with the Cdk1-driven transcriptional program, provided that cells are exposed to the appropriate Cdk1 activities. These findings contrast with current models that propose self-sustained and Cdk1-independent transcriptional oscillations. Our work therefore supports a model in which Cdk1 activity serves as a quantitative platform for coordinating cell cycle transitions with the expression of critical genes to bring about proper cell cycle progression. PMID:27045731

  16. Sunspot number recalibration: The ~1840–1920 anomaly in the observer normalization factors of the group sunspot number

    Directory of Open Access Journals (Sweden)

    Cliver Edward W.

    2017-01-01

    Full Text Available We analyze the normalization factors (k′-factors used to scale secondary observers to the Royal Greenwich Observatory (RGO reference series of the Hoyt & Schatten (1998a, 1998b group sunspot number (GSN. A time series of these k′-factors exhibits an anomaly from 1841 to 1920, viz., the average k′-factor for all observers who began reporting groups from 1841 to 1883 is 1.075 vs. 1.431 for those who began from 1884 to 1920, with a progressive rise, on average, during the latter period. The 1883–1884 break between the two subintervals occurs precisely at the point where Hoyt and Schatten began to use a complex daisy-chaining method to scale observers to RGO. The 1841–1920 anomaly implies, implausibly, that the average sunspot observer who began from 1841 to 1883 was nearly as proficient at counting groups as mid-20th century RGO (for which k′ = 1.0 by definition while observers beginning during the 1884–1920 period regressed in group counting capability relative to those from the earlier interval. Instead, as shown elsewhere and substantiated here, RGO group counts increased relative to those of other long-term observers from 1874 to ~1915. This apparent inhomogeneity in the RGO group count series is primarily responsible for the increase in k′-factors from 1884 to 1920 and the suppression, by 44% on average, of the Hoyt and Schatten GSN relative to the original Wolf sunspot number (WSN before ~1885. Correcting for the early “learning curve” in the RGO reference series and minimizing the use of daisy-chaining rectifies the anomalous behavior of the k′-factor series. The resultant GSN time series (designated GSN* is in reasonable agreement with the revised WSN (SN*; Clette & Lefèvre 2016 and the backbone-based group sunspot number (RGS; Svalgaard & Schatten 2016 but significantly higher than other recent reconstructions (Friedli, personal communication, 2016; Lockwood et al. 2014a, 2014b; Usoskin et al. 2016a. This result

  17. POLITICAL MONETARY CYCLES IN COALITION AND SINGLE PARTY GOVERNMENT PERIODS: A CASE STUDY ON TURKEY

    Directory of Open Access Journals (Sweden)

    AHMET EMRAH TAYYAR

    2017-12-01

    Full Text Available According to the theory of political monetary cycles, the government manipulates monetary policy during election periods in order to be re-elected. According to the said theory, expansionary monetary policies are implemented before the elections with opportunistic objective, while the contractionary monetary policies are implemented to stabilize the economy immediately after the elections. The use of monetary policy instruments for political purposes depends on the presence of a non-autonomous central bank, flexible exchange rate regime in the country, and the coordination between fiscal and monetary policies. Thus, the changes in the monetary policy indicators in election periods during coalition and single party governments in Turkey between 1990 and 2016 were examined in the present study. The money in circulation (M0, M1 money supply, domestic loans and inflation series were analyzed with the seasonal Box-Jenkins method for the above mentioned periods. Based on the findings of the study, political monetary cycles were not observed during the 1990-2000 coalition governments. It was determined that there were political monetary cycles during the single party government period between 2000 and 2016.Furthermore, although it could be expected that the political monetary cycles would be removed with the liberalization of the Turkish central bank on 25 April 2001, the existence of political monetary cycles during the period of 2000-2016 indicates that central bank independence was not fully achieved in Turkey. Based on another finding of the present study, the lack of political monetary cycles during the coalition government periods could lead to the failure in financing the budget deficit that increase due to political reasons with monetary policies. However, due to the existence of political monetary cycles during the single party government period, it could be argued that politically induced budget deficits changed in consistence with the

  18. Comparison of several hydrological cycle parameters in Croatia for two periods

    International Nuclear Information System (INIS)

    Pandzic, Kreso; Trninic, Dusan

    2004-01-01

    Comparison of several hydrological cycle parameter averages for two periods in Croatia is considered. Parameters are: yearly averages of: 2m air temperature, precipitation amounts, potential and real evapotranspiration amounts. A basic period (1951-1980) and period for comparison (1981-1997) have been chosen. (These periods accepted at The First Sub-Regional Expert Meeting on the 'Assesment of Climate Change Impacts on the Hydrological Cycles in South-Eastern Europe' held in Sofia (Bulgaria) 17-20 February 1999.) Differences between two period averages for 30 weather stations have been calculated. Temperature differences and those for potential evaporation are positive while for precipitation they are mainly negative. Real evaporation differences for two periods are an exception i.e. they are positive in continental but negative in Mediterranean part of Croatia. These results agree with global warming trend. (Author)

  19. Long-Period Solar Variability

    Energy Technology Data Exchange (ETDEWEB)

    GAUTHIER,JOHN H.

    2000-07-20

    Terrestrial climate records and historical observations of the Sun suggest that the Sun undergoes aperiodic oscillations in radiative output and size over time periods of centuries and millenia. Such behavior can be explained by the solar convective zone acting as a nonlinear oscillator, forced at the sunspot-cycle frequency by variations in heliomagnetic field strength. A forced variant of the Lorenz equations can generate a time series with the same characteristics as the solar and climate records. The timescales and magnitudes of oscillations that could be caused by this mechanism are consistent with what is known about the Sun and terrestrial climate.

  20. Nonparametric Inference for Periodic Sequences

    KAUST Repository

    Sun, Ying

    2012-02-01

    This article proposes a nonparametric method for estimating the period and values of a periodic sequence when the data are evenly spaced in time. The period is estimated by a "leave-out-one-cycle" version of cross-validation (CV) and complements the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes multiples of the smallest period, leading to a "virtually" consistent estimator of integer periods. This estimator is investigated both theoretically and by simulation.We also propose a nonparametric test of the null hypothesis that the data have constantmean against the alternative that the sequence of means is periodic. Finally, our methodology is demonstrated on three well-known time series: the sunspots and lynx trapping data, and the El Niño series of sea surface temperatures. © 2012 American Statistical Association and the American Society for Quality.

  1. The Strongest Magnetic Field in Sunspots

    Science.gov (United States)

    Okamoto, J.; Sakurai, T.

    2017-12-01

    Sunspots are concentrations of magnetic fields on the solar surface. Generally, the strongest magnetic field in each sunspot is located in the dark umbra in most cases. A typical field strength in sunspots is around 3,000 G. On the other hand, some exceptions also have been found in complex sunspots with bright regions such as light bridges that separate opposite polarity umbrae, for instance with a strength of 4,300 G. However, the formation mechanism of such strong fields outside umbrae is still puzzling. Here we report an extremely strong magnetic field in a sunspot, which was located in a bright region sandwiched by two opposite-polarity umbrae. The strength is 6,250 G, which is the largest ever observed since the discovery of magnetic field on the Sun in 1908 by Hale. We obtained 31 scanned maps of the active region observed by Hinode/SOT/SP with a cadence of 3 hours over 5 days (February 1-6, 2014). Considering the spatial and temporal evolution of the vector magnetic field and the Doppler velocity in the bright region, we suggested that this strong field region was generated as a result of compression of one umbra pushed by the outward flow from the other umbra (Evershed flow), like the subduction of the Earth's crust in plate tectonics.

  2. Sunspot drawings handwritten character recognition method based on deep learning

    Science.gov (United States)

    Zheng, Sheng; Zeng, Xiangyun; Lin, Ganghua; Zhao, Cui; Feng, Yongli; Tao, Jinping; Zhu, Daoyuan; Xiong, Li

    2016-05-01

    High accuracy scanned sunspot drawings handwritten characters recognition is an issue of critical importance to analyze sunspots movement and store them in the database. This paper presents a robust deep learning method for scanned sunspot drawings handwritten characters recognition. The convolution neural network (CNN) is one algorithm of deep learning which is truly successful in training of multi-layer network structure. CNN is used to train recognition model of handwritten character images which are extracted from the original sunspot drawings. We demonstrate the advantages of the proposed method on sunspot drawings provided by Chinese Academy Yunnan Observatory and obtain the daily full-disc sunspot numbers and sunspot areas from the sunspot drawings. The experimental results show that the proposed method achieves a high recognition accurate rate.

  3. Annual reconstruction of the solar cycle from atmospheric 14C variations

    International Nuclear Information System (INIS)

    Murphy, J.O.

    1990-01-01

    Initially, the rise and fall components of the 11-year solar sunspot cycle are approximated by separate least-squares polynomials for four cycle classifications, which are determined by the magnitude of the average of the annual sunspot numbers per cycle. Following a method is formulated to generate detailed reconstruction of the annual variation of a solar cycle based on this cycle average, and the results obtained for cycles -4 through to 21 are compared with the annual Zurich values. This procedure is then employed to establish annual sunspot numbers using published average cycle values obtained from atmospheric carbon 14 variations, which have been derived from the chemical analysis of tree ring sections. The reconstructed sequences are correlated with the observed cycle values and with tree ring width index chronologies which exhibit a significant 11-year periodicity. It is anticipated that the long carbon 14 records and parallel dendrochronological data could be employed to obtain a more detailed portrayal of previous periods of strong solar activity than that given by current estimates based on historical records. 17 refs., 2 tabs., 9 figs

  4. Limit cycles bifurcating from the periodic annulus of cubic homogeneous polynomial centers

    Directory of Open Access Journals (Sweden)

    Jaume Llibre

    2015-10-01

    Full Text Available We obtain an explicit polynomial whose simple positive real roots provide the limit cycles which bifurcate from the periodic orbits of any cubic homogeneous polynomial center when it is perturbed inside the class of all polynomial differential systems of degree n.

  5. Avian predation pressure as a potential driver of periodical cicada cycle length

    Science.gov (United States)

    Walter E. Koenig; Andrew M. Liebhold

    2013-01-01

    The extraordinarily long life cycles, synchronous emergences at 13- or 17-year intervals, and complex geographic distribution of periodical cicadas (Magicicada spp.) in eastern North America are a long-standing evolutionary enigma. Although a variety of factors, including satiation of aboveground predators and avoidance of interbrood hybridization,...

  6. A seven day running training period increases basal urinary hepcidin levels as compared to cycling

    NARCIS (Netherlands)

    Sim, M.; Dawson, B.; Landers, G.J.; Swinkels, D.W.; Tjalsma, H.; Wiegerinck, E.T.G.; Trinder, D.; Peeling, P.

    2014-01-01

    BACKGROUND: This investigation compared the effects of an extended period of weight-bearing (running) vs. non-weight-bearing (cycling) exercise on hepcidin production and its implications for iron status. METHODS: Ten active males performed two separate exercise training blocks with either running

  7. Diode laser heterodyne observations of silicon monoxide in sunspots - A test of three sunspot models

    Science.gov (United States)

    Glenar, D. A.; Deming, D.; Jennings, D. E.; Kostiuk, T.; Mumma, M. J.

    1983-01-01

    Absorption features from the 8 micron SiO fundamental (upsilon = 1-0) and hot bands (upsilon = 2-1) have been observed in sunspots at sub-Doppler resolution using a ground-based tunable diode laser heterodyne spectrometer. The observed line widths suggest an upper limit of 0.5 km/s for the microturbulent velocity in sunspot umbrae. Since the silicon monoxide abundance is very sensitive to sunspot temperature, the measured equivalent widths permit an unambiguous determination of the temperature-pressure relation in the upper layers of the umbral atmosphere. In the region of SiO line formation (log P sub g = 3.0-4.5), the results support the sunspot model suggested by Stellmacher and Wiehr (1970).

  8. On the structure of small sunspots

    International Nuclear Information System (INIS)

    Ringnes, T.S.

    1984-01-01

    The smallest and most short-lived sunspots are decribed differently at the observatories in Zuerich and Greenwich. These differences which seem to originate both from the observing procedure and from the definitions of penumbra and umbra adopted, are further discussed

  9. Predicting the start and maximum amplitude of solar cycle 24 using similar phases and a cycle grouping

    International Nuclear Information System (INIS)

    Wang Jialong; Zong Weiguo; Le Guiming; Zhao Haijuan; Tang Yunqiu; Zhang Yang

    2009-01-01

    We find that the solar cycles 9, 11, and 20 are similar to cycle 23 in their respective descending phases. Using this similarity and the observed data of smoothed monthly mean sunspot numbers (SMSNs) available for the descending phase of cycle 23, we make a date calibration for the average time sequence made of the three descending phases of the three cycles, and predict the start of March or April 2008 for cycle 24. For the three cycles, we also find a linear correlation of the length of the descending phase of a cycle with the difference between the maximum epoch of this cycle and that of its next cycle. Using this relationship along with the known relationship between the rise-time and the maximum amplitude of a slowly rising solar cycle, we predict the maximum SMSN of cycle 24 of 100.2 ± 7.5 to appear during the period from May to October 2012. (letters)

  10. Sunspot Positions and Areas from Observations by Galileo Galilei

    Science.gov (United States)

    Vokhmyanin, M. V.; Zolotova, N. V.

    2018-02-01

    Sunspot records in the seventeenth century provide important information on the solar activity before the Maunder minimum, yielding reliable sunspot indices and the solar butterfly diagram. Galilei's letters to Cardinal Francesco Barberini and Marcus Welser contain daily solar observations on 3 - 11 May, 2 June - 8 July, and 19 - 21 August 1612. These historical archives do not provide the time of observation, which results in uncertainty in the sunspot coordinates. To obtain them, we present a method that minimizes the discrepancy between the sunspot latitudes. We provide areas and heliographic coordinates of 82 sunspot groups. In contrast to Sheiner's butterfly diagram, we found only one sunspot group near the Equator. This provides a higher reliability of Galilei's drawings. Large sunspot groups are found to emerge at the same longitude in the northern hemisphere from 3 May to 21 August, which indicates an active longitude.

  11. On period doubling bifurcations of cycles and the harmonic balance method

    International Nuclear Information System (INIS)

    Itovich, Griselda R.; Moiola, Jorge L.

    2006-01-01

    This works attempts to give quasi-analytical expressions for subharmonic solutions appearing in the vicinity of a Hopf bifurcation. Starting with well-known tools as the graphical Hopf method for recovering the periodic branch emerging from classical Hopf bifurcation, precise frequency and amplitude estimations of the limit cycle can be obtained. These results allow to attain approximations for period doubling orbits by means of harmonic balance techniques, whose accuracy is established by comparison of Floquet multipliers with continuation software packages. Setting up a few coefficients, the proposed methodology yields to approximate solutions that result from a second period doubling bifurcation of cycles and to extend the validity limits of the graphical Hopf method

  12. Inheritance of Cell-Cycle Duration in the Presence of Periodic Forcing

    Science.gov (United States)

    Mosheiff, Noga; Martins, Bruno M. C.; Pearl-Mizrahi, Sivan; Grünberger, Alexander; Helfrich, Stefan; Mihalcescu, Irina; Kohlheyer, Dietrich; Locke, James C. W.; Glass, Leon; Balaban, Nathalie Q.

    2018-04-01

    Periodic forcing of nonlinear oscillators leads to a large number of dynamic behaviors. The coupling of the cell cycle to the circadian clock provides a biological realization of such forcing. A previous model of forcing leads to nontrivial relations between correlations along cell lineages. Here, we present a simplified two-dimensional nonlinear map for the periodic forcing of the cell cycle. Using high-throughput single-cell microscopy, we have studied the correlations between cell-cycle duration in discrete lineages of several different organisms, including those with known coupling to a circadian clock and those without known coupling to a circadian clock. The model reproduces the paradoxical correlations and predicts new features that can be compared with the experimental data. By fitting the model to the data, we extract the important parameters that govern the dynamics. Interestingly, the model reproduces bimodal distributions for cell-cycle duration, as well as the gating of cell division by the phase of the clock, without having been explicitly fed into the model. In addition, the model predicts that circadian coupling may increase cell-to-cell variability in a clonal population of cells. In agreement with this prediction, deletion of the circadian clock reduces variability. Our results show that simple correlations can identify systems under periodic forcing and that studies of nonlinear coupling of biological oscillators provide insight into basic cellular processes of growth.

  13. COMPARISON OF CHAOTIC AND FRACTAL PROPERTIES OF POLAR FACULAE WITH SUNSPOT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Deng, L. H.; Xiang, Y. Y.; Dun, G. T. [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216 (China); Li, B., E-mail: wooden@escience.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Shandong University at Weihai, Weihai 264209 (China)

    2016-01-15

    The solar magnetic activity is governed by a complex dynamo mechanism and exhibits a nonlinear dissipation behavior in nature. The chaotic and fractal properties of solar time series are of great importance to understanding the solar dynamo actions, especially with regard to the nonlinear dynamo theories. In the present work, several nonlinear analysis approaches are proposed to investigate the nonlinear dynamical behavior of the polar faculae and sunspot activity for the time interval from 1951 August to 1998 December. The following prominent results are found: (1) both the high- and the low-latitude solar activity are governed by a three-dimensional chaotic attractor, and the chaotic behavior of polar faculae is the most complex, followed by that of the sunspot areas, and then the sunspot numbers; (2) both the high- and low-latitude solar activity exhibit a high degree of persistent behavior, and their fractal nature is due to such long-range correlation; (3) the solar magnetic activity cycle is predictable in nature, but the high-accuracy prediction should only be done for short- to mid-term due to its intrinsically dynamical complexity. With the help of the Babcock–Leighton dynamo model, we suggest that the nonlinear coupling of the polar magnetic fields with strong active-region fields exhibits a complex manner, causing the statistical similarities and differences between the polar faculae and the sunspot-related indicators.

  14. Regulation of the yeast metabolic cycle by transcription factors with periodic activities

    Directory of Open Access Journals (Sweden)

    Pellegrini Matteo

    2011-10-01

    Full Text Available Abstract Background When growing budding yeast under continuous, nutrient-limited conditions, over half of yeast genes exhibit periodic expression patterns. Periodicity can also be observed in respiration, in the timing of cell division, as well as in various metabolite levels. Knowing the transcription factors involved in the yeast metabolic cycle is helpful for determining the cascade of regulatory events that cause these patterns. Results Transcription factor activities were estimated by linear regression using time series and genome-wide transcription factor binding data. Time-translation matrices were estimated using least squares and were used to model the interactions between the most significant transcription factors. The top transcription factors have functions involving respiration, cell cycle events, amino acid metabolism and glycolysis. Key regulators of transitions between phases of the yeast metabolic cycle appear to be Hap1, Hap4, Gcn4, Msn4, Swi6 and Adr1. Conclusions Analysis of the phases at which transcription factor activities peak supports previous findings suggesting that the various cellular functions occur during specific phases of the yeast metabolic cycle.

  15. Extreme Value Theory Applied to the Millennial Sunspot Number Series

    Science.gov (United States)

    Acero, F. J.; Gallego, M. C.; García, J. A.; Usoskin, I. G.; Vaquero, J. M.

    2018-01-01

    In this work, we use two decadal sunspot number series reconstructed from cosmogenic radionuclide data (14C in tree trunks, SN 14C, and 10Be in polar ice, SN 10Be) and the extreme value theory to study variability of solar activity during the last nine millennia. The peaks-over-threshold technique was used to compute, in particular, the shape parameter of the generalized Pareto distribution for different thresholds. Its negative value implies an upper bound of the extreme SN 10Be and SN 14C timeseries. The return level for 1000 and 10,000 years were estimated leading to values lower than the maximum observed values, expected for the 1000 year, but not for the 10,000 year return levels, for both series. A comparison of these results with those obtained using the observed sunspot numbers from telescopic observations during the last four centuries suggests that the main characteristics of solar activity have already been recorded in the telescopic period (from 1610 to nowadays) which covers the full range of solar variability from a Grand minimum to a Grand maximum.

  16. Sunspot splitting triggering an eruptive flare

    Science.gov (United States)

    Louis, Rohan E.; Puschmann, Klaus G.; Kliem, Bernhard; Balthasar, Horst; Denker, Carsten

    2014-02-01

    Aims: We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Methods: Continuum intensity, line-of-sight magnetogram, and dopplergram data of the Helioseismic and Magnetic Imager were employed to analyse the photospheric evolution. Filtergrams in Hα and He I 10830 Å of the Chromospheric Telescope at the Observatorio del Teide, Tenerife, track the evolution of the flare. The corresponding coronal conditions were derived from 171 Å and 304 Å images of the Atmospheric Imaging Assembly. Local correlation tracking was utilized to determine shear flows. Results: Emerging flux formed a neutral line ahead of the leading sunspot and new satellite spots. The sunspot splitting caused a long-lasting flow towards this neutral line, where a filament formed. Further flux emergence, partly of mixed polarity, as well as episodes of flux cancellation occurred repeatedly at the neutral line. Following a nearby C-class precursor flare with signs of interaction with the filament, the filament erupted nearly simultaneously with the onset of the M5.6 flare and evolved into a coronal mass ejection. The sunspot stretched without forming a light bridge, splitting unusually fast (within about a day, complete ≈6 h after the eruption) in two nearly equal parts. The front part separated strongly from the active region to approach the neighbouring active region where all its coronal magnetic connections were rooted. It also rotated rapidly (by 4.9° h-1) and caused significant shear flows at its edge. Conclusions: The eruption resulted from a complex sequence of processes in the (sub-)photosphere and corona. The persistent flows towards the neutral line likely caused the formation of a flux rope that held the filament. These flows, their associated flux cancellation, the emerging flux, and the precursor flare all contributed to the destabilization of the flux rope. We

  17. Quasi-periodic Pulsations in the Most Powerful Solar Flare of Cycle 24

    Science.gov (United States)

    Kolotkov, Dmitrii Y.; Pugh, Chloe E.; Broomhall, Anne-Marie; Nakariakov, Valery M.

    2018-05-01

    Quasi-periodic pulsations (QPPs) are common in solar flares and are now regularly observed in stellar flares. We present the detection of two different types of QPP signals in the thermal emission light curves of the X9.3-class solar flare SOL2017-09-06T12:02, which is the most powerful flare of Cycle 24. The period of the shorter-period QPP drifts from about 12 to 25 s during the flare. The observed properties of this QPP are consistent with a sausage oscillation of a plasma loop in the flaring active region. The period of the longer-period QPP is about 4 to 5 minutes. Its properties are compatible with standing slow magnetoacoustic oscillations, which are often detected in coronal loops. For both QPP signals, other mechanisms such as repetitive reconnection cannot be ruled out, however. The studied solar flare has an energy in the realm of observed stellar flares, and the fact that there is evidence of a short-period QPP signal typical of solar flares along with a long-period QPP signal more typical of stellar flares suggests that the different ranges of QPP periods typically observed in solar and stellar flares is likely due to observational constraints, and that similar physical processes may be occurring in solar and stellar flares.

  18. Vertical gradients of sunspot magnetic fields

    Science.gov (United States)

    Hagyard, M. J.; Teuber, D.; West, E. A.; Tandberg-Hanssen, E.; Henze, W., Jr.; Beckers, J. M.; Bruner, M.; Hyder, C. L.; Woodgate, B. E.

    1983-01-01

    The results of a Solar Maximum Mission (SMM) guest investigation to determine the vertical gradients of sunspot magnetic fields for the first time from coordinated observations of photospheric and transition-region fields are described. Descriptions are given of both the photospheric vector field of a sunspot, derived from observations using the NASA Marshall Space Flight Center vector magnetograph, and of the line-of-sight component in the transition region, obtained from the SMM Ultraviolet Spectrometer and Polarimeter instrument. On the basis of these data, vertical gradients of the line-of-sight magnetic field component are calculated using three methods. It is found that the vertical gradient of Bz is lower than values from previous studies and that the transition-region field occurs at a height of approximately 4000-6000 km above the photosphere.

  19. Probing sunspots with two-skip time-distance helioseismology

    Science.gov (United States)

    Duvall, Thomas L., Jr.; Cally, Paul S.; Przybylski, Damien; Nagashima, Kaori; Gizon, Laurent

    2018-06-01

    Context. Previous helioseismology of sunspots has been sensitive to both the structural and magnetic aspects of sunspot structure. Aims: We aim to develop a technique that is insensitive to the magnetic component so the two aspects can be more readily separated. Methods: We study waves reflected almost vertically from the underside of a sunspot. Time-distance helioseismology was used to measure travel times for the waves. Ray theory and a detailed sunspot model were used to calculate travel times for comparison. Results: It is shown that these large distance waves are insensitive to the magnetic field in the sunspot. The largest travel time differences for any solar phenomena are observed. Conclusions: With sufficient modeling effort, these should lead to better understanding of sunspot structure.

  20. Towards a first detailed reconstruction of sunspot information over the last 150 years

    Science.gov (United States)

    Lefevre, Laure; Clette, Frédéric

    2013-04-01

    With four centuries of solar evolution, the International Sunspot Number (SSN) forms the longest solar time series currently available. It provides an essential reference for understanding and quantifying how the solar output has varied over decades and centuries and thus for assessing the variations of the main natural forcing on the Earth climate. For such a quantitative use, this unique time-series must be closely monitored for any possible biases and drifts. This is the main objective of the Sunspot Workshops organized jointly by the National Solar Observatory (NSO) and the Royal Observatory of Belgium (ROB) since 2010. Here, we will report about some recent outcomes of past workshops, like diagnostics of scaling errors and their proposed corrections, or the recent disagreement between the sunspot sumber and other solar indices like the 10.7cm radio flux. Our most recent analyses indicate that while part of this divergence may be due to a calibration drift in the SSN, it also results from an intrinsic change in the global magnetic parameters of sunspots and solar active regions, suggesting a possible transition to a new activity regime. Going beyond the SSN series, in the framework of the SOTERIA, TOSCA and SOLID projects, we produced a survey of all existing catalogs providing detailed sunspot information and we also located different primary solar images and drawing collections that can be exploitable to complement the existing catalogs (COMESEP project). These are first steps towards the construction of a multi-parametric time series of multiple sunspot group properties over at least the last 150 years, allowing to reconstruct and extend the current 1-D SSN series. By bringing new spatial, morphological and evolutionary information, such a data set should bring major advances for the modeling of the solar dynamo and solar irradiance. We will present here the current status of this work. The catalog now extends over the last 3 cycles (Lefevre & Clette 2011

  1. Status report on potential future nuclear energy cycles in the period 1982-2020

    International Nuclear Information System (INIS)

    1982-11-01

    The demand for electrical power and the availability of fuel to supply it is the driving force behind any change in the electrical supply technology. A survey of a number of recent world wide electrical power growth projections indicates a growth rate of between 2 percent and 4 percent within the period of 1980 to 2020. In some countries, such as France and Japan, without large domestic supplies of conventional fuels, there is a significant effort to extend supplies of uranium using advanced fuel cycles and breeder reactors. In North America, and in particular the United States, there would appear to be adequate supplies of conventional fuel for the projected growth for the period of the study. Development of advanced fuel cycles in this case will be driven by economic considerations rather than strategic ones. A review of the current status of fusion test facilities is included in the report, but the consensus of opinion of the literature surveyed would indicate that no commercial scale generating plant will be operational within the study period

  2. Questioning the Influence of Sunspots on Amazon Hydrology: Even a Broken Clock Tells the Right Time Twice a Day

    Science.gov (United States)

    Baker, J. C. A.; Gloor, M.; Boom, A.; Neill, D. A.; Cintra, B. B. L.; Clerici, S. J.; Brienen, R. J. W.

    2018-02-01

    It was suggested in a recent article that sunspots drive decadal variation in Amazon River flow. This conclusion was based on a novel time series decomposition method used to extract a decadal signal from the Amazon River record. We have extended this analysis back in time, using a new hydrological proxy record of tree ring oxygen isotopes (δ18OTR). Consistent with the findings of Antico and Torres, we find a positive correlation between sunspots and the decadal δ18OTR cycle from 1903 to 2012 (r = 0.60, p r = -0.30, p = 0.11, 1799-1902). This result casts considerable doubt over the mechanism by which sunspots are purported to influence Amazon hydrology.

  3. On proton events of different solar activity cycles

    International Nuclear Information System (INIS)

    Sattarov, I.; Sherdanov, Ch.; Sattarov, B.

    1997-01-01

    In solar activity cycle N21 and N22 the latitude distribution of the proton large flares and sunspot groups is being studied. It was found that higher proton activity of cycle N22 is connected with its higher latitude sunspot activity (author)

  4. Variations and Regularities in the Hemispheric Distributions in Sunspot Groups of Various Classes

    Science.gov (United States)

    Gao, Peng-Xin

    2018-05-01

    The present study investigates the variations and regularities in the distributions in sunspot groups (SGs) of various classes in the northern and southern hemispheres from Solar Cycles (SCs) 12 to 23. Here, we use the separation scheme that was introduced by Gao, Li, and Li ( Solar Phys. 292, 124, 2017), which is based on A/U ( A is the corrected area of the SG, and U is the corrected umbral area of the SG), in order to separate SGs into simple SGs (A/U ≤ 4.5) and complex SGs (A/U > 6.2). The time series of Greenwich photoheliographic results from 1875 to 1976 (corresponding to complete SCs 12 - 20) and Debrecen photoheliographic data during the period 1974 - 2015 (corresponding to complete SCs 21 - 23) are used to show the distributions of simple and complex SGs in the northern and southern hemispheres. The main results we obtain are reported as follows: i) the larger of the maximum annual simple SG numbers in the two hemispheres and the larger of the maximum annual complex SG numbers in the two hemispheres occur in different hemispheres during SCs 12, 14, 18, and 19; ii) the relative changing trends of two curves - cumulative SG numbers in the northern and southern hemispheres - for simple SGs are different from those for complex SGs during SCs 12, 14, 18, and 21; and iii) there are discrepancies between the dominant hemispheres of simple and complex SGs for SCs 12, 14, 18, and 21.

  5. Long-period intensity pulsations in the solar corona during activity cycle 23

    Science.gov (United States)

    Auchère, F.; Bocchialini, K.; Solomon, J.; Tison, E.

    2014-03-01

    We report on the detection (10σ) of 917 events of long-period (3 to 16 h) intensity pulsations in the 19.5 nm passband of the SOHO Extreme ultraviolet Imaging Telescope. The data set spans from January 1997 to July 2010, i.e. the entire solar cycle 23 and the beginning of cycle 24. The events can last for up to six days and have relative amplitudes up to 100%. About half of the events (54%) are found to happen in active regions, and 50% of these have been visually associated with coronal loops. The remaining 46% are localized in the quiet Sun. We performed a comprehensive analysis of the possible instrumental artefacts and we conclude that the observed signal is of solar origin. We discuss several scenarios that could explain the main characteristics of the active region events. The long periods and the amplitudes observed rule out any explanation in terms of magnetohydrodynamic waves. Thermal non-equilibrium could produce the right periods, but it fails to explain all the observed properties of coronal loops and the spatial coherence of the events. We propose that moderate temporal variations of the heating term in the energy equation, so as to avoid a thermal non-equilibrium state, could be sufficient to explain those long-period intensity pulsations. The large number of detections suggests that these pulsations are common in active regions. This would imply that the measurement of their properties could provide new constraints on the heating mechanisms of coronal loops. Movies are available in electronic form at http://www.aanda.org

  6. Tracking the Magnetic Flux in and Around Sunspots

    Energy Technology Data Exchange (ETDEWEB)

    Sheeley, N. R. Jr.; Stauffer, J. R.; Thomassie, J. C.; Warren, H. P., E-mail: solsheeley@verizon.net, E-mail: harry.warren@nrl.navy.mil [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)

    2017-02-10

    We have developed a procedure for tracking sunspots observed by the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory and for making curvature-corrected space/time maps of the associated line-of-sight magnetic field and continuum intensity. We apply this procedure to 36 sunspots, each observed continuously for nine days around its central meridian passage time, and find that the proper motions separate into two distinct components depending on their speeds. Fast (∼3–5 km s{sup −1}) motions, comparable to Evershed flows, are produced by weak vertical fluctuations of the horizontal canopy field and recur on a timescale of 12–20 min. Slow (∼0.3–0.5 km s{sup −1}) motions diverge from a sunspot-centered ring whose location depends on the size of the sunspot, occurring in the mid-penumbra for large sunspots and at the outer edge of the penumbra for small sunspots. The slow ingoing features are contracting spokes of a quasi-vertical field of umbral polarity. These inflows disappear when the sunspot loses its penumbra, and may be related to inward-moving penumbral grain. The slow outgoing features may have either polarity depending on whether they originate from quasi-vertical fields of umbral polarity or from the outer edge of the canopy. When a sunspot decays, the penumbra and canopy disappear, and the moat becomes filled with slow outflows of umbral polarity. We apply our procedure to decaying sunspots, to long-lived sunspots, and to numerical simulations of a long-lived sunspot by Rempel.

  7. The statistical properties of spread F observed at Hainan station during the declining period of the 23rd solar cycle

    Directory of Open Access Journals (Sweden)

    G. J. Wang

    2010-06-01

    Full Text Available The temporal variations of the low latitude nighttime spread F (SF observed by DPS-4 digisonde at low latitude Hainan station (geog. 19.5° N, 109.1° E, dip lat. 9.5° N during the declining solar cycle 23 from March 2002 to February 2008 are studied. The spread F measured by the digisonde were classified into four types, i.e., frequency SF (FSF, range SF (RSF, mixed SF (MSF, and strong range SF (SSF. The statistical results show that MSF and SSF are the outstanding irregularities in Hainan, MSF mainly occurs during summer and low solar activity years, whereas SSF mainly occurs during equinoxes and high solar activity years. The SSF has a diurnal peak before midnight and usually appears during 20:00–02:00 LT, whereas MSF peaks nearly or after midnight and occurs during 22:00–06:00 LT. The time of maximum occurrence of SSF is later in summer than in equinoxes and this time delay can be caused by the later reversal time of the E×B drift in summer. The SunSpot Number (SSN dependence of each type SF is different during different season. The FSF is independent of SSN during each season; RSF with SSN is positive relation during equinoxes and summer and is no relationship during the winter; MSF is significant dependence on SSN during the summer and winter, and does not relate to SSN during the equinoxes; SSF is clearly increasing with SSN during equinoxes and summer, while it is independent of SSN during the winter. The occurrence numbers of each type SF and total SF have the same trend, i.e., increasing as Kp increases from 0 to 1, and then decreasing as increasing Kp. The correlation with Kp is negative for RSF, MSF, SSF and total SF, but is vague for the FSF.

  8. Periods of weed interference in maize crops cultivated in the first and second cycles

    Directory of Open Access Journals (Sweden)

    Caio Ferraz de Campos

    2016-10-01

    Full Text Available The interference of weeds in maize production may be reflected in grain yield losses that vary as a function of the density, stage and degree of aggressiveness of the species present. In the agricultural ecosystem, crops and weeds demand light, water, nutrients and space, which are frequently not available in sufficient quantities, leading to competition. The aim of this work was to determine the period of interference of weed plants, in particular of naked crabgrass (Digitaria nuda on maize crop in the first and second harvest. The treatments were defined as increasing periods of coexistence and increasing control of weed community (7, 14, 21, 28, 35, 42, 49, and 56 days, two more controls, a control including one with weed control until the end of the culture cycle and another with coexistence until the harvest. For each period, were evaluated the stand of maize plants, length of ear, number of grains per row, number of rows per ear, cob, 100-grain weight, and grain productivity. The data obtained were subjected to analysis of variance using the F test, with average treatments compared using Tukey’s test at 5% probability. Crop productivity was evaluated by means of regressions, the critical periods of interference were estimated. The critical timing of weed removal was 25 days for both harvests. The critical weed free period was 54 and 27 days for the first and second harvest respectively. For the conditions of the first and second harvest, the critical period of weed control was of 29 and 2 days respectively.

  9. Towards the automatic detection and analysis of sunspot rotation

    Science.gov (United States)

    Brown, Daniel S.; Walker, Andrew P.

    2016-10-01

    Torsional rotation of sunspots have been noted by many authors over the past century. Sunspots have been observed to rotate up to the order of 200 degrees over 8-10 days, and these have often been linked with eruptive behaviour such as solar flares and coronal mass ejections. However, most studies in the literature are case studies or small-number studies which suffer from selection bias. In order to better understand sunspot rotation and its impact on the corona, unbiased large-sample statistical studies are required (including both rotating and non-rotating sunspots). While this can be done manually, a better approach is to automate the detection and analysis of rotating sunspots using robust methods with well characterised uncertainties. The SDO/HMI instrument provide long-duration, high-resolution and high-cadence continuum observations suitable for extracting a large number of examples of rotating sunspots. This presentation will outline the analysis of SDI/HMI data to determine the rotation (and non-rotation) profiles of sunspots for the complete duration of their transit across the solar disk, along with how this can be extended to automatically identify sunspots and initiate their analysis.

  10. The EUV Spectrum of Sunspot Plumes Observed by SUMER on ...

    Indian Academy of Sciences (India)

    tribpo

    Abstract. We present results from sunspot observations obtained by. SUMER on SOHO. In sunspot plumes the EUV spectrum differs from the quiet Sun; continua are observed with different slopes and intensities; emission lines from molecular hydrogen and many unidentified species indicate unique plasma conditions ...

  11. Sunspot Modeling: From Simplified Models to Radiative MHD Simulations

    Directory of Open Access Journals (Sweden)

    Rolf Schlichenmaier

    2011-09-01

    Full Text Available We review our current understanding of sunspots from the scales of their fine structure to their large scale (global structure including the processes of their formation and decay. Recently, sunspot models have undergone a dramatic change. In the past, several aspects of sunspot structure have been addressed by static MHD models with parametrized energy transport. Models of sunspot fine structure have been relying heavily on strong assumptions about flow and field geometry (e.g., flux-tubes, "gaps", convective rolls, which were motivated in part by the observed filamentary structure of penumbrae or the necessity of explaining the substantial energy transport required to maintain the penumbral brightness. However, none of these models could self-consistently explain all aspects of penumbral structure (energy transport, filamentation, Evershed flow. In recent years, 3D radiative MHD simulations have been advanced dramatically to the point at which models of complete sunspots with sufficient resolution to capture sunspot fine structure are feasible. Here overturning convection is the central element responsible for energy transport, filamentation leading to fine-structure and the driving of strong outflows. On the larger scale these models are also in the progress of addressing the subsurface structure of sunspots as well as sunspot formation. With this shift in modeling capabilities and the recent advances in high resolution observations, the future research will be guided by comparing observation and theory.

  12. An essay on sunspots and solar flares

    International Nuclear Information System (INIS)

    Akasofu, S.-I.

    1984-01-01

    The presently prevailing theories of sunspots and solar flares rely on the hypothetical presence of magnetic flux tubes beneath the photosphere and the two subsequent hypotheses, their emergence above the photosphere and explosive magnetic reconnection, converting magnetic energy carried by the flux tubes for solar flare energy. In this paper, attention is paid to the fact that there are large-scale magnetic fields which divide the photosphere into positive and negative (line-of-sight) polarity regions and that they are likely to be more fundamental than sunspot fields, as emphasized most recently by McIntosh. A new phenomenological model of the sunspot pair formation is then constructed by considering an amplification process of these large-scale fields near their boundaries by shear flows, including localized vortex motions. The amplification results from a dynamo process associated with such vortex flows and the associated convergence flow in the large-scale fields. This dynamo process generates also some of the familiar ''force-free'' fields or the ''sheared'' magnetic fields in which the magnetic field-aligned currents are essential. Upward field-aligned currents generated by the dynamo process are carried by downward streaming electrons which are expected to be accelerated by an electric potential structure; a similar structure is responsible for accelerating auroral electrons in the magnetosphere. Depending on the magnetic field configuration and the shear flows, the current-carrying electrons precipitate into different geometrical patterns, causing circular flares, umbral flares, two-ribbon flares, etc. Thus, it is suggested that ''low temperature flares'' are directly driven by the photospheric dynamo process. (author)

  13. Solar rotation and meridional motions derived from sunspot groups

    International Nuclear Information System (INIS)

    Tuominen, J.; Tuominen, I.; Kyroelaeinen, J.

    1982-01-01

    Latitudinal and longitudinal motions of sunspot groups have been studied using the positions of recurrent sunspot groups of 103 years published by Greenwich observatory. In order to avoid any limb effects, only positions close to the central meridian have been used. The data were divided into two parts: those belonging to the years around sunspot maxima and those belonging to the years around sunspot minima. Using several different criteria it was ascertained that sunspot groups show meridional motions and that their drift curves as a function of latitude are different around maxima and around minima. In addition, also the angular velocity, as a function of latitude, was found to be different around maxima and minima. (Auth.)

  14. Iwahashi Zenbei's Sunspot Drawings in 1793 in Japan

    Science.gov (United States)

    Hayakawa, Hisashi; Iwahashi, Kiyomi; Tamazawa, Harufumi; Toriumi, Shin; Shibata, Kazunari

    2018-01-01

    Three Japanese sunspot drawings associated with Iwahashi Zenbei (1756 - 1811) are shown here from contemporary manuscripts and woodprint documents with the relevant texts. We reveal the observational date of one of the drawings to be 26 August 1793, and the overall observations lasted for over a year. Moreover, we identify the observational site for the dated drawing as Fushimi in Japan. We then compare Zenbei's observations with the group sunspot number and the raw group count from the Sunspot Index and Long-term Solar Observations (SILSO) to reveal the context of the data, and we conclude that these drawings fill gaps in our understanding that are due to the fragmental sunspot observations around 1793. These drawings are important as a clue to evaluate astronomical knowledge of contemporary Japan in the late eighteenth century and are valuable as a non-European observation, considering that most sunspot observations up to the middle of the nineteenth century are from Europe.

  15. Periodic expression of nuclear and mitochondrial DNA replication genes during the trypanosomatid cell cycle.

    Science.gov (United States)

    Pasion, S G; Brown, G W; Brown, L M; Ray, D S

    1994-12-01

    In trypanosomatids, DNA replication in the nucleus and in the single mitochondrion (or kinetoplast) initiates nearly simultaneously, suggesting that the DNA synthesis (S) phases of the nucleus and the mitochondrion are coordinately regulated. To investigate the basis for the temporal link between nuclear and mitochondrial DNA synthesis phases the expression of the genes encoding DNA ligase I, the 51 and 28 kDa subunits of replication protein A, dihydrofolate reductase and the mitochondrial type II topoisomerase were analyzed during the cell cycle progression of synchronous cultures of Crithidia fasciculata. These DNA replication genes were all expressed periodically, with peak mRNA levels occurring just prior to or at the peak of DNA synthesis in the synchronized cultures. A plasmid clone (pdN-1) in which TOP2, the gene encoding the mitochondrial topoisomerase, was disrupted by the insertion of a NEO drug-resistance cassette was found to express both a truncated TOP2 mRNA and a truncated topoisomerase polypeptide. The truncated mRNA was also expressed periodically coordinate with the expression of the endogenous TOP2 mRNA indicating that cis elements necessary for periodic expression are contained within cloned sequences. The expression of both TOP2 and nuclear DNA replication genes at the G1/S boundary suggests that regulated expression of these genes may play a role in coordinating nuclear and mitochondrial S phases in trypanosomatids.

  16. Closed Nuclear Fuel Cycle Technologies to Meet Near-Term and Transition Period Requirements

    International Nuclear Information System (INIS)

    Collins, E.D.; Felker, L.K.; Benker, D.E.; Campbell, D.O.

    2008-01-01

    A scenario that very likely fits conditions in the U.S. nuclear power industry and can meet the goals of cost minimization, waste minimization, and provisions of engineered safeguards for proliferation resistance, including no separated plutonium, to close the fuel cycle with full actinide recycle is evaluated. Processing aged fuels, removed from the reactor for 30 years or more, can provide significant advantages in cost reduction and waste minimization. The UREX+3 separations process is being developed to separate used fuel components for reuse, thus minimizing waste generation and storage in geologic repositories. Near-term use of existing and new thermal spectrum reactors can be used initially for recycle actinide transmutation. A transition period will eventually occur, when economic conditions will allow commercial deployment of fast reactors; during this time, recycled plutonium can be diverted into fast reactor fuel and conversion of depleted uranium into additional fuel material can be considered. (authors)

  17. Life-cycle cost and payback period analysis for commercial unitary air conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Rosenquist, Greg; Coughlin, Katie; Dale, Larry; McMahon, James; Meyers, Steve

    2004-03-31

    This report describes an analysis of the economic impacts of possible energy efficiency standards for commercial unitary air conditioners and heat pumps on individual customers in terms of two metrics: life-cycle cost (LCC) and payback period (PBP). For each of the two equipment classes considered, the 11.5 EER provides the largest mean LCC savings. The results show how the savings vary among customers facing different electricity prices and other conditions. At 11.5 EER, at least 80% of the users achieve a positive LCC savings. At 12.0 EER, the maximum efficiency analyzed, mean LCC savings are lower but still positive. For the {ge} $65,000 Btu/h to <135,000 Btu/h equipment class, 59% of users achieve a positive LCC savings. For the $135,000 Btu/h to <240,000 Btu/h equipment class, 91% of users achieve a positive LCC savings.

  18. Closed Nuclear Fuel Cycle Technologies to Meet Near-Term and Transition Period Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Collins, E.D.; Felker, L.K.; Benker, D.E.; Campbell, D.O. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee, 37831-6152 (United States)

    2008-07-01

    A scenario that very likely fits conditions in the U.S. nuclear power industry and can meet the goals of cost minimization, waste minimization, and provisions of engineered safeguards for proliferation resistance, including no separated plutonium, to close the fuel cycle with full actinide recycle is evaluated. Processing aged fuels, removed from the reactor for 30 years or more, can provide significant advantages in cost reduction and waste minimization. The UREX+3 separations process is being developed to separate used fuel components for reuse, thus minimizing waste generation and storage in geologic repositories. Near-term use of existing and new thermal spectrum reactors can be used initially for recycle actinide transmutation. A transition period will eventually occur, when economic conditions will allow commercial deployment of fast reactors; during this time, recycled plutonium can be diverted into fast reactor fuel and conversion of depleted uranium into additional fuel material can be considered. (authors)

  19. Updated on effluents releases of the CEA nuclear fuel cycle facilities - 1995 to 2010 period

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Nelson Luiz Dias [Centro Tecnologico da Marinha em Sao Paulo (CTMSP) Sao Paulo, SP (Brazil)

    2011-07-01

    The environmental impact assessment of the Centro Experimental Aramar (CEA) facilities has been presented in a former work, based on the measured effluent releases data, for the period from 1995 to 2007. This work shows the update up to 2010. The effluents releases to the environment result from the routine operation of CEA nuclear fuel cycle facilities (LEI - Isotopic Enrichment Laboratory, USIDE - Pilot Plant for Industrial Verification of Uranium Enrichment and LABMAT - Nuclear Materials Laboratory). Basically, this work presents the radioactive release source terms, as described at the CEA Effluent Report sent to the National Commission for Nuclear Energy (CNEN) each semester, and a historical assessment of the critical group annual doses from 1995 up to 2010. The assessed doses are compared to the maximum dose constraint as well as to the exemption level specified by CNEN. (author)

  20. Updated on effluents releases of the CEA nuclear fuel cycle facilities - 1995 to 2010 period

    International Nuclear Information System (INIS)

    Ferreira, Nelson Luiz Dias

    2011-01-01

    The environmental impact assessment of the Centro Experimental Aramar (CEA) facilities has been presented in a former work, based on the measured effluent releases data, for the period from 1995 to 2007. This work shows the update up to 2010. The effluents releases to the environment result from the routine operation of CEA nuclear fuel cycle facilities (LEI - Isotopic Enrichment Laboratory, USIDE - Pilot Plant for Industrial Verification of Uranium Enrichment and LABMAT - Nuclear Materials Laboratory). Basically, this work presents the radioactive release source terms, as described at the CEA Effluent Report sent to the National Commission for Nuclear Energy (CNEN) each semester, and a historical assessment of the critical group annual doses from 1995 up to 2010. The assessed doses are compared to the maximum dose constraint as well as to the exemption level specified by CNEN. (author)

  1. Intercropping of taro and sunn hemp with cutting periods during the cycle

    Directory of Open Access Journals (Sweden)

    João Nacir Colombo

    Full Text Available ABSTRACT Intercropping using legumes is one of the ways to protect the main crop, and in long term improve the physical and chemical properties of the soil. The aim of this work was to evaluate the intercropping of Colocasia esculenta (L. Schott (taro and the tropical legume Crotalaria juncea L. (sunn hemp, cutting sunn hemp at ten periods during the cycle. The experiment was carried out under field conditions between 09/23/2010 and 06/04/2011. It consisted of 11 treatments related to the 10 cutting times of sunn hemp (55, 70, 85,100, 115, 130, 145, 160, 190, and 220 days after sowing - DAS plus a control of taro with no sunn hemp. During the cycle, taro was evaluated for plant height and incidence of leaf burn. At the time of cutting the sunn hemp, the plant height, fresh and dry matter masses, and nutrient content of the biomass were calculated. During taro harvest, we evaluated the productivity of the mother rhizomes and classified the cormels. Taro plants shaded by sunn hemp showed a lower incidence of leaf burn. The sunn hemp cut from 145 DAS onwards affected the yield of comercial rhizomes and total and agroeconomic indexes. Sunn hemp cut up to 130 DAS provided better performance of taro, without compromising productivity and economic indicators, with the highest amounts of N and K observed in the biomass cut at 115 DAS.

  2. Efficacy of peeling during different periods of the menstrual cycle on acne.

    Science.gov (United States)

    Bulbul Baskan, Emel; Tilki Günay, Işıl; Saricaoglu, Hayriye

    2017-10-01

    The aim of this study was to investigate the efficacy of 50% glycolic acid peeling performed at different phases of menstruation on acne. This study included 30 patients with mild-to-moderate acne. Those with regular menstrual cycles and no history or laboratory evidence of hormonal pathology, hirsutism were selected. Thirty patients were divided in three groups. The first group received peeling applications in the first 7 days of menstruation; the second group received the peel between 10 and 14 days; and the third group received the peel during the last 10 days of menstruation. The 30 female patients included in study. All patients' menstrual cycles were regular. All groups were homogenous in terms of initial acne severity scores. Acne severity scores decreased in all groups after 3 months of therapy; statistically significant differences were achieved only in the second group. The results of our study suggest that chemical peeling administered during ovulation provides the most significant benefit for acne lesions. Ovulation is the period when estrogen reaches its highest level. Estrogen decreases sebum production through different mechanisms. The beneficial effects of estrogen on acne and healing in combination with those of chemical peeling may cause synergistic therapeutic effects with pronounced results.

  3. Sustainability of a Compartmentalized Host-Parasite Replicator System under Periodic Washout-Mixing Cycles

    Directory of Open Access Journals (Sweden)

    Taro Furubayashi

    2018-01-01

    Full Text Available The emergence and dominance of parasitic replicators are among the major hurdles for the proliferation of primitive replicators. Compartmentalization of replicators is proposed to relieve the parasite dominance; however, it remains unclear under what conditions simple compartmentalization uncoupled with internal reaction secures the long-term survival of a population of primitive replicators against incessant parasite emergence. Here, we investigate the sustainability of a compartmentalized host-parasite replicator (CHPR system undergoing periodic washout-mixing cycles, by constructing a mathematical model and performing extensive simulations. We describe sustainable landscapes of the CHPR system in the parameter space and elucidate the mechanism of phase transitions between sustainable and extinct regions. Our findings revealed that a large population size of compartments, a high mixing intensity, and a modest amount of nutrients are important factors for the robust survival of replicators. We also found two distinctive sustainable phases with different mixing intensities. These results suggest that a population of simple host–parasite replicators assumed before the origin of life can be sustained by a simple compartmentalization with periodic washout-mixing processes.

  4. Periodicity in a Conceptual Model of Glacial Cycles in the Absence of Milankovitch Forcing

    Science.gov (United States)

    Hahn, J.; Walsh, J.; Widiasih, E.; McGehee, R.

    2015-12-01

    Previously, McGehee and Widiasih coupled Budyko's Energy Balance Model with dynamics of a latitudinal ice-line incorporating the albedo feedback effect. They reduced this model to a two-dimensional equation of global mean temperature and a latitudinal ice-line. With this conceptual model, we now include dynamics of the ablation and accumulation of ice, to form a three-dimensional system that partitions the regions of the Earth latitudinally into an accumulation zone, ablation zone, and ice-free zone. Motivated by the findings of Abe-Ouchi et al that the fast retreat of ice-sheets is due to an increased rate of ablation via the effects of delayed isostatic rebound, we incorporate a simple switching mechanism to the model which increases the rate of ablation during periods of glacial retreat. This forms a discontinuous system of the Earth's temperature and ice-volume in which we find a stable periodic orbit. This can be interpreted as a intrinsic cycling of the Earth's climate in the absence of Milankovitch forcing.

  5. A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups

    Science.gov (United States)

    Ruždjak, Domagoj; Brajša, Roman; Sudar, Davor; Skokić, Ivica; Poljančić Beljan, Ivana

    2017-12-01

    The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differential-rotation parameters A and B. These differential-rotation parameters were compared with the solar-activity level. We found that the Sun rotates more differentially at the minimum than at the maximum of activity during the epoch 1977 - 2016. An inverse correlation between equatorial rotation and solar activity was found using the recently revised sunspot number. The secular decrease of the equatorial rotation rate that accompanies the increase in activity stopped in the last part of the twentieth century. It was noted that when a significant peak in equatorial rotation velocity is observed during activity minimum, the next maximum is weaker than the previous one.

  6. Two-rate periodic protocol with dynamics driven through many cycles

    Science.gov (United States)

    Kar, Satyaki

    2017-02-01

    We study the long time dynamics in closed quantum systems periodically driven via time dependent parameters with two frequencies ω1 and ω2=r ω1 . Tuning of the ratio r there can unleash plenty of dynamical phenomena to occur. Our study includes integrable models like Ising and X Y models in d =1 and the Kitaev model in d =1 and 2 and can also be extended to Dirac fermions in graphene. We witness the wave-function overlap or dynamic freezing that occurs within some small/ intermediate frequency regimes in the (ω1,r ) plane (with r ≠0 ) when the ground state is evolved through a single cycle of driving. However, evolved states soon become steady with long driving, and the freezing scenario gets rarer. We extend the formalism of adiabatic-impulse approximation for many cycle driving within our two-rate protocol and show the near-exact comparisons at small frequencies. An extension of the rotating wave approximation is also developed to gather an analytical framework of the dynamics at high frequencies. Finally we compute the entanglement entropy in the stroboscopically evolved states within the gapped phases of the system and observe how it gets tuned with the ratio r in our protocol. The minimally entangled states are found to fall within the regime of dynamical freezing. In general, the results indicate that the entanglement entropy in our driven short-ranged integrable systems follow a genuine nonarea law of scaling and show a convergence (with a r dependent pace) towards volume scaling behavior as the driving is continued for a long time.

  7. THE MINIMUM OF SOLAR CYCLE 23: AS DEEP AS IT COULD BE?

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz-Jaramillo, Andrés; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Senkpeil, Ryan R. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Tlatov, Andrey G. [Kislovodsk Mountain Astronomical Station of the Pulkovo Observatory, Kislovodsk 357700 (Russian Federation); Pevtsov, Alexei A. [National Solar Observatory, Sunspot, NM 88349 (United States); Balmaceda, Laura A. [Institute for Astronomical, Terrestrial and Space Sciences (ICATE-CONICET), San Juan (Argentina); DeLuca, Edward E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Martens, Petrus C. H., E-mail: munoz@solar.physics.montana.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)

    2015-05-01

    In this work we introduce a new way of binning sunspot group data with the purpose of better understanding the impact of the solar cycle on sunspot properties and how this defined the characteristics of the extended minimum of cycle 23. Our approach assumes that the statistical properties of sunspots are completely determined by the strength of the underlying large-scale field and have no additional time dependencies. We use the amplitude of the cycle at any given moment (something we refer to as activity level) as a proxy for the strength of this deep-seated magnetic field. We find that the sunspot size distribution is composed of two populations: one population of groups and active regions and a second population of pores and ephemeral regions. When fits are performed at periods of different activity level, only the statistical properties of the former population, the active regions, are found to vary. Finally, we study the relative contribution of each component (small-scale versus large-scale) to solar magnetism. We find that when hemispheres are treated separately, almost every one of the past 12 solar minima reaches a point where the main contribution to magnetism comes from the small-scale component. However, due to asymmetries in cycle phase, this state is very rarely reached by both hemispheres at the same time. From this we infer that even though each hemisphere did reach the magnetic baseline, from a heliospheric point of view the minimum of cycle 23 was not as deep as it could have been.

  8. An econometric investigation of the sunspot number record since the year 1700 and its prediction into the 22nd century

    Science.gov (United States)

    Travaglini, Guido

    2015-09-01

    Solar activity, as measured by the yearly revisited time series of sunspot numbers (SSN) for the period 1700-2014 (Clette et al., 2014), undergoes in this paper a triple statistical and econometric checkup. The conclusions are that the SSN sequence: (1) is best modeled as a signal that features nonlinearity in mean and variance, long memory, mean reversion, 'threshold' symmetry, and stationarity; (2) is best described as a discrete damped harmonic oscillator which linearly approximates the flux-transport dynamo model; (3) its prediction well into the 22nd century testifies of a substantial fall of the SSN centered around the year 2030. In addition, the first and last Gleissberg cycles show almost the same peak number and height during the period considered, yet the former slightly prevails when measured by means of the estimated smoother. All of these conclusions are achieved by making use of modern tools developed in the field of Financial Econometrics and of two new proposed procedures for signal smoothing and prediction.

  9. STOCHASTIC DESCRIPTION OF THE HIGH-FREQUENCY CONTENT OF DAILY SUNSPOTS AND EVIDENCE FOR REGIME CHANGES

    International Nuclear Information System (INIS)

    Shapoval, A.; Le Mouël, J.-L.; Courtillot, V.; Shnirman, M.

    2015-01-01

    The irregularity index λ is applied to the high-frequency content of daily sunspot numbers ISSN. This λ is a modification of the standard maximal Lyapunov exponent. It is computed here as a function of embedding dimension m, within four-year time windows centered at the maxima of Schwabe cycles. The λ(m) curves form separate clusters (pre-1923 and post-1933). This supports a regime transition and narrows its occurrence to cycle 16, preceding the growth of activity leading to the Modern Maximum. The two regimes are reproduced by a simple autoregressive process AR(1), with the mean of Poisson noise undergoing 11 yr modulation. The autocorrelation a of the process (linked to sunspot lifetime) is a ≈ 0.8 for 1850-1923 and ≈0.95 for 1933-2013. The AR(1) model suggests that groups of spots appear with a Poisson rate and disappear at a constant rate. We further applied the irregularity index to the daily sunspot group number series for the northern and southern hemispheres, provided by the Greenwich Royal Observatory (RGO), in order to study a possible desynchronization. Correlations between the north and south λ(m) curves vary quite strongly with time and indeed show desynchronization. This may reflect a slow change in the dimension of an underlying dynamical system. The ISSN and RGO series of group numbers do not imply an identical mechanism, but both uncover a regime change at a similar time. Computation of the irregularity index near the maximum of cycle 24 will help in checking whether yet another regime change is under way

  10. The Large Scale Magnetic Field and Sunspot Cycles

    Indian Academy of Sciences (India)

    tribpo

    Financial support for this work comes from the Russian Fund Basic Research, Grant. 99 02 16200 and 00 02 16355, INTAS 98 1088 and NRA 98 OSS 08. References. Makarov, V. I., Tlatov, A. G. 1999, in Proceedings of the 9th Meeting on Solar Physics (Italy),. 125. Makarov, V. I., Tlatov, A. G. 2000, Astron. Rep., (in press).

  11. Sunspots Resource--From Ancient Cultures to Modern Research

    Science.gov (United States)

    Craig, N.

    2000-10-01

    Sunspots is a web-based lesson that was developed by the Science Education Gateway (SEGway) program with participants from the Exploratorium, a well known science Museum in San Francisco, UC Berkeley Space Sciences Laboratory, and teachers from several California schools. This space science resource allows 8-12 grade students to explore the nature of sunspots and the history of solar physics in its effort to understand their nature. Interviews with solar physicists and archeo-astronomers, historic images, cutting-edge NASA images, movies, and research results, as well as a student-centered sunspot research activity using NASA space science data defines this lesson. The sunspot resource is aligned with the NCTM and National Science Education Standards. It emphasizes inquiry-based methods and mathematical exercises through measurement, graphic data representation, analysis of NASA data, lastly, interpreting results and drawing conclusions. These resources have been successfully classroom tested in 4 middle schools in the San Francisco Unified School District as part of the 3-week Summer School Science curricula. Lessons learned from the Summer School 1999 will be explained. This resource includes teacher-friendly lesson plans, space science background material and student worksheets. There will be Sunspots lesson CD-ROM and printed version of the relevant classroom-ready materials and a teacher resource booklet available. Sunspot resource is brought to you by, The Science Education Gateway - SEGway - Project, and the HESSI satellite and NASA's Office of Space Science Sun-Earth Connection Education Forum.

  12. LKR/SDH plays important roles throughout the tick life cycle including a long starvation period.

    Directory of Open Access Journals (Sweden)

    Banzragch Battur

    Full Text Available BACKGROUND: Lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH is a bifunctional enzyme catalyzing the first two steps of lysine catabolism in plants and mammals. However, to date, the properties of the lysine degradation pathway and biological functions of LKR/SDH have been very little described in arthropods such as ticks. METHODOLOGY/PRINCIPAL FINDINGS: We isolated and characterized the gene encoding lysine-ketoglutarate reductase (LKR, EC 1.5.1.8 and saccharopine dehydrogenase (SDH, EC 1.5.1.9 from a tick, Haemaphysalis longicornis, cDNA library that encodes a bifunctional polypeptide bearing domains similar to the plant and mammalian LKR/SDH enzymes. Expression of LKR/SDH was detected in all developmental stages, indicating an important role throughout the tick life cycle, including a long period of starvation after detachment from the host. The LKR/SDH mRNA transcripts were more abundant in unfed and starved ticks than in fed and engorged ticks, suggesting that tick LKR/SDH are important for the starved tick. Gene silencing of LKR/SDH by RNAi indicated that the tick LKR/SDH plays an integral role in the osmotic regulation of water balance and development of eggs in ovary of engorged females. CONCLUSIONS/SIGNIFICANCE: Transcription analysis and gene silencing of LKR/SDH indicated that tick LKR/SDH enzyme plays not only important roles in egg production, reproduction and development of the tick, but also in carbon, nitrogen and water balance, crucial physiological processes for the survival of ticks. This is the first report on the role of LKR/SDH in osmotic regulation in animals including vertebrate and arthropods.

  13. Mid-term periodicities and heliospheric modulation of coronal index and solar flare index during solar cycles 22-23

    Science.gov (United States)

    Singh, Prithvi Raj; Saxena, A. K.; Tiwari, C. M.

    2018-04-01

    We applied fast Fourier transform techniques and Morlet wavelet transform on the time series data of coronal index, solar flare index, and galactic cosmic ray, for the period 1986-2008, in order to investigate the long- and mid-term periodicities including the Rieger ({˜ }130 to {˜ }190 days), quasi-period ({˜ }200 to {˜ }374 days), and quasi-biennial periodicities ({˜ }1.20 to {˜ }3.27 years) during the combined solar cycles 22-23. We emphasize the fact that a lesser number of periodicities are found in the range of low frequencies, while the higher frequencies show a greater number of periodicities. The rotation rates at the base of convection zone have periods for coronal index of {˜ }1.43 years and for solar flare index of {˜ }1.41 year, and galactic cosmic ray, {˜ }1.35 year, during combined solar cycles 22-23. In relation to these two solar parameters (coronal index and solar flare index), for the solar cycles 22-23, we found that galactic cosmic ray modulation at mid cut-off rigidity (Rc = 2.43GV) is anti-correlated with time-lag of few months.

  14. Interactions between nested sunspots. 1: The formation and breakup of a delta-type sunspot

    Science.gov (United States)

    Gaizauskas, V.; Harvey, K. L.; Proulx, M.

    1994-01-01

    We investigate a nest of sunspots in which three ordinary bipolar pairs of sunspots are aligned collinearly. The usual spreading action of the growing regions brings two spots of leading polarity together (p-p collision) and forces the leading and trailing spots of the two interior regions to overlap inot a single penumbra (p-f collision), thus forming a delta-spot. We examine digitally processed images from the Ottawa River Solar Observatory of two related events inside the delta-spot 5 days after the p-f collision begins: the violent disruption of the f-umbra, and the formation in less than a day of an hydrogen-alpha filament. The evolutionary changes in shape, area, relative motions, and brightness that we measure for each spot in the elongated nest are more compatible with Parker's (1979a) hypothesis of a sunspot as a cluster of flux tubes held together by downdrafts than with the notion of a sunspot as a monolithic plug of magnetic flux. From chromospheric developments over the delta-spot, we show that a shearing motion along a polarity inversion is more effective than convergence for creating a chromospheric filament. We invoke the release of an instability, triggered by a sequence of processes lasting 1 day or more, to explain the disruption of the f-umbra in this delta-spot. We show that the sequence is initiated when the colliding p-f umbrae reach a critical separation around 3200 +/- 200 km. We present a descriptive model in which the reconnected magnetic fields block vertical transport of convective heat flux just beneath the photosphere. We observe the formation of an unusual type of penumbra adjacent to the f-polarity portion of this delta-spot just before its disruption. A tangential penumbral band grows out of disordered matter connected to the f-umbra. We present this as evidence for the extrusion of umbral magnetic flux by thermal plumes rising through a loosely bound umbra.

  15. Magnet Cycles and Stability Periods of the CMS Structures from 2008 to 2013 as Observed by the Link Alignment System

    International Nuclear Information System (INIS)

    Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Molinero, A.; Navarrete, J.; Oller, J.C.

    2015-01-01

    In this document Magnet Cycles and Stability Periods of the CMS Experiment are studied with the recorded Alignment Link System data along the 2008 to 2013 years of operation. The motions of the mechanical structures due to the magnetic field forces are studied including an in-depth analysis of the relative distance between the endcap structures and the central Tracker body during the Stability Periods to verify the mechanical stability of the detector during the physics data taking.

  16. Understanding Solar Cycle Variability

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, R. H.; Schüssler, M., E-mail: cameron@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2017-07-10

    The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock–Leighton-type dynamo model confirm the validity of the normal-mode approach.

  17. Will Solar Cycles 25 and 26 Be Weaker than Cycle 24?

    Science.gov (United States)

    Javaraiah, J.

    2017-11-01

    The study of variations in solar activity is important for understanding the underlying mechanism of solar activity and for predicting the level of activity in view of the activity impact on space weather and global climate. Here we have used the amplitudes (the peak values of the 13-month smoothed international sunspot number) of Solar Cycles 1 - 24 to predict the relative amplitudes of the solar cycles during the rising phase of the upcoming Gleissberg cycle. We fitted a cosine function to the amplitudes and times of the solar cycles after subtracting a linear fit of the amplitudes. The best cosine fit shows overall properties (periods, maxima, minima, etc.) of Gleissberg cycles, but with large uncertainties. We obtain a pattern of the rising phase of the upcoming Gleissberg cycle, but there is considerable ambiguity. Using the epochs of violations of the Gnevyshev-Ohl rule (G-O rule) and the `tentative inverse G-O rule' of solar cycles during the period 1610 - 2015, and also using the epochs where the orbital angular momentum of the Sun is steeply decreased during the period 1600 - 2099, we infer that Solar Cycle 25 will be weaker than Cycle 24. Cycles 25 and 26 will have almost same strength, and their epochs are at the minimum between the current and upcoming Gleissberg cycles. In addition, Cycle 27 is expected to be stronger than Cycle 26 and weaker than Cycle 28, and Cycle 29 is expected to be stronger than both Cycles 28 and 30. The maximum of Cycle 29 is expected to represent the next Gleissberg maximum. Our analysis also suggests a much lower value (30 - 40) for the maximum amplitude of the upcoming Cycle 25.

  18. SEISMIC DISCRIMINATION OF THERMAL AND MAGNETIC ANOMALIES IN SUNSPOT UMBRAE

    International Nuclear Information System (INIS)

    Lindsey, C.; Cally, P. S.; Rempel, M.

    2010-01-01

    Efforts to model sunspots based on helioseismic signatures need to discriminate between the effects of (1) a strong magnetic field that introduces time-irreversible, vantage-dependent phase shifts, apparently connected to fast- and slow-mode coupling and wave absorption and (2) a thermal anomaly that includes cool gas extending an indefinite depth beneath the photosphere. Helioseismic observations of sunspots show travel times considerably reduced with respect to equivalent quiet-Sun signatures. Simulations by Moradi and Cally of waves skipping across sunspots with photospheric magnetic fields of order 3 kG show travel times that respond strongly to the magnetic field and relatively weakly to the thermal anomaly by itself. We note that waves propagating vertically in a vertical magnetic field are relatively insensitive to the magnetic field, while remaining highly responsive to the attendant thermal anomaly. Travel-time measurements for waves with large skip distances into the centers of axially symmetric sunspots are therefore a crucial resource for discrimination of the thermal anomaly beneath sunspot umbrae from the magnetic anomaly. One-dimensional models of sunspot umbrae based on compressible-radiative-magnetic-convective simulations such as by Rempel et al. can be fashioned to fit observed helioseismic travel-time spectra in the centers of sunspot umbrae. These models are based on cooling of the upper 2-4 Mm of the umbral subphotosphere with no significant anomaly beneath 4.5 Mm. The travel-time reductions characteristic of these models are primarily a consequence of a Wilson depression resulting from a strong downward buoyancy of the cooled umbral medium.

  19. Umbral oscillations as a probe of sunspot

    International Nuclear Information System (INIS)

    Abdelatif, T.E.H.

    1985-01-01

    The interaction of the solar five-minute oscillations with a sunspot is thoroughly explored, both on observational and theoretical grounds. Simple theoretical models are developed in order to understand the observations of umbral oscillations. Observations made at the National Solar Observatory detected both the three-minute and five-minute umbral oscillations at photospheric heights. The three-minute oscillations were found to have a kinetic energy density six times higher in the photosphere than in the chromosphere and to be concentrated in the central part of the umbra, supporting the photospheric resonance theory for the three-minute umbral oscillations. The five-minute oscillations are attenuated in the umbra, which appears to act as a filter in selecting some of the peaks in the power spectrum of five-minute oscillations in the surrounding photosphere. The k-omega power spectrum of the umbral oscillations shows a shift of power to longer wavelengths. Theoretical models of the transmission of acoustic waves into a magnetic region explain both observed effects

  20. Microbial Nitrogen-Cycle Gene Abundance in Soil of Cropland Abandoned for Different Periods.

    Directory of Open Access Journals (Sweden)

    Huhe

    Full Text Available In Inner Mongolia, steppe grasslands face desertification or degradation because of human overuse and abandonment after inappropriate agricultural management. The soils in these abandoned croplands exist in heterogeneous environments characterized by widely fluctuating microbial growth. Quantitative polymerase chain reaction analysis of microbial genes encoding proteins involved in the nitrogen cycle was used to study Azotobacter species, nitrifiers, and denitrifiers in the soils from steppe grasslands and croplands abandoned for 2, 6, and 26 years. Except for nitrifying archaea and nitrous oxide-reducing bacteria, the relative genotypic abundance of microbial communities involved in nitrogen metabolism differed by approximately 2- to 10-fold between abandoned cropland and steppe grassland soils. Although nitrogen-cycle gene abundances varied with abandonment time, the abundance patterns of nitrogen-cycle genes separated distinctly into abandoned cropland versus light-grazing steppe grassland, despite the lack of any cultivation for over a quarter-century. Plant biomass and plant diversity exerted a significant effect on the abundance of microbial communities that mediate the nitrogen cycle (P < 0.002 and P < 0.03, respectively. The present study elucidates the ecology of bacteria that mediate the nitrogen cycle in recently abandoned croplands.

  1. Microbial Nitrogen-Cycle Gene Abundance in Soil of Cropland Abandoned for Different Periods.

    Science.gov (United States)

    Huhe; Borjigin, Shinchilelt; Buhebaoyin; Wu, Yanpei; Li, Minquan; Cheng, Yunxiang

    2016-01-01

    In Inner Mongolia, steppe grasslands face desertification or degradation because of human overuse and abandonment after inappropriate agricultural management. The soils in these abandoned croplands exist in heterogeneous environments characterized by widely fluctuating microbial growth. Quantitative polymerase chain reaction analysis of microbial genes encoding proteins involved in the nitrogen cycle was used to study Azotobacter species, nitrifiers, and denitrifiers in the soils from steppe grasslands and croplands abandoned for 2, 6, and 26 years. Except for nitrifying archaea and nitrous oxide-reducing bacteria, the relative genotypic abundance of microbial communities involved in nitrogen metabolism differed by approximately 2- to 10-fold between abandoned cropland and steppe grassland soils. Although nitrogen-cycle gene abundances varied with abandonment time, the abundance patterns of nitrogen-cycle genes separated distinctly into abandoned cropland versus light-grazing steppe grassland, despite the lack of any cultivation for over a quarter-century. Plant biomass and plant diversity exerted a significant effect on the abundance of microbial communities that mediate the nitrogen cycle (P nitrogen cycle in recently abandoned croplands.

  2. Countermeasures to cope with issues for the FBR cycle system and transitional core during FBR introductory period

    International Nuclear Information System (INIS)

    Fujimura, Koji; Sasahira, Akira; Yamashita, Junichi; Fukasawa, Tetsuo; Hoshino, Kuniyoshi

    2007-01-01

    The introduction of fast breeder reactors (FBRs) requires Pu be recovered from light water reactors (LWRs) spent fuel. The 'Flexible Fuel Cycle Initiative (FFCI)' can supply enough Pu and holds no surplus Pu, while responding flexibly to future technical and social uncertainties. In this paper, the potential of FFCI to increase economy of the fuel cycle system was investigated. On the other hand, during the FBR introductory period, Pu from LWR spent fuel is used for startup of FBRs. But the FBR core being loaded with Pu from LWR spent fuel has a larger burnup reactivity than the core being loaded with Pu from the FBR multi-recycling core. The increased burnup reactivity may reduce the cycle length of the FBR core. In this paper, an FBR transitional core concept to handle the issues of the FBR introductory period was investigated. The results obtained through this study are as follows. (1) The FFCI has a potential to flatten the reprocessing amount of LWR spent fuel and to increase economy of the next fuel cycle system. (2) Minor actinides - mixed FBR transitional core has a potential to maintain the operation cycle length even supposing use of Pu from LWR spent fuel. (author)

  3. Periodic cycle of stretching and breaking of the head of gravity currents

    Science.gov (United States)

    Nogueira, H. I. S.; Adduce, C.; Alves, E.; Franca, M. J.

    2012-04-01

    its particular buoyancy drives the advance of the current, with a different celerity from the tail. The head is highly concentrated being the main engine of convection of the released mass, being subjected to entrainment at the interface with the ambient fluid. The aim of the present work is to experimentally investigate the dynamics of the head, including continuous entrainment and cycles of stretching and breaking observed in the laboratory. Experiments were conducted at the Laboratory of Hydraulics of University of Rome "Roma Tre" in a 3.0 m long, 0.20 m wide and 0.30 m deep transparent Perspex flume. Four lock-exchange release tests were performed varying the density of the saline water. For smooth bed and for a fixed value of water depth, h = 0.20 m, the following four different initial densities of the salt-water mixture were analysed: 1015, 1030, 1045 and 1060 kg/m3. A controlled quantity of dye is added to the saline water in the lock to provide flow visualization and to serve as density tracer. The development of the current is recorded with a 25 Hz CCD camera under controlled light conditions. The resulting video frames are thus converted into grey scale matrices and a calibration procedure establishes a non-linear relation, experimentally determined, between the gray scale values and the quantity of dye in the water. The quantity of dye is converted into salt concentration by assuming a linear relation between quantities, dye and salt, allowing thus the estimation of the 2D instantaneous current density distribution. The experiments allowed the observation of the dynamics of the head of unsteady density currents in detail, including a cyclic increase in dimension and mass due to entrainment followed by a division in two distinct patches. A frontal one continues the drive downstream whereas a subsequent one is left behind and incorporated in the tail, thus indicating that the loss of saline mass in the head is not only due to continuous entrainment at the

  4. Observational Evidence of a Flux Rope within a Sunspot Umbra

    Energy Technology Data Exchange (ETDEWEB)

    Guglielmino, Salvo L.; Zuccarello, Francesca [Dipartimento di Fisica e Astronomia—Sezione Astrofisica, Università di Catania, Via S. Sofia 78, I-95125 Catania (Italy); Romano, Paolo, E-mail: salvo.guglielmino@oact.inaf.it [INAF—Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95125 Catania (Italy)

    2017-09-10

    We observed an elongated filamentary bright structure inside the umbra of the big sunspot in active region NOAA 12529, which differs from the light bridges usually observed in sunspots for its morphology, magnetic configuration, and velocity field. We used observations taken with the Solar Dynamic Observatory satellite to characterize this feature. Its lifetime is 5 days, during which it reaches a maximum length of about 30″. In the maps of the vertical component of the photospheric magnetic field, a portion of the feature has a polarity opposite to that of the hosting sunspot. At the same time, in the entire feature the horizontal component of the magnetic field is about 2000 G, substantially stronger than in the surrounding penumbral filaments. Doppler velocity maps reveal the presence of both upward and downward plasma motions along the structure at the photospheric level. Moreover, looking at the chromospheric level, we noted that it is located in a region corresponding to the edge of a small filament that seems rooted in the sunspot umbra. Therefore, we interpreted the bright structure as the photospheric counterpart of a flux rope touching the sunspot and giving rise to penumbral-like filaments in the umbra.

  5. TILT ANGLE AND FOOTPOINT SEPARATION OF SMALL AND LARGE BIPOLAR SUNSPOT REGIONS OBSERVED WITH HMI

    International Nuclear Information System (INIS)

    McClintock, B. H.; Norton, A. A.

    2016-01-01

    We investigate bipolar sunspot regions and how tilt angle and footpoint separation vary during emergence and decay. The Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory collects data at a higher cadence than historical records and allows for a detailed analysis of regions over their lifetimes. We sample the umbral tilt angle, footpoint separation, and umbral area of 235 bipolar sunspot regions in Helioseismic and Magnetic Imager—Debrecen Data with an hourly cadence. We use the time when the umbral area peaks as time zero to distinguish between the emergence and decay periods of each region and we limit our analysis of tilt and separation behavior over time to within ±96 hr of time zero. Tilt angle evolution is distinctly different for regions with small (≈30 MSH), midsize (≈50 MSH), and large (≈110 MSH) maximum umbral areas, with 45 and 90 MSH being useful divisions for separating the groups. At the peak umbral area, we determine median tilt angles for small (7.°6), midsize (5.°9), and large (9.°3) regions. Within ±48 hr of the time of peak umbral area, large regions steadily increase in tilt angle, midsize regions are nearly constant, and small regions show evidence of negative tilt during emergence. A period of growth in footpoint separation occurs over a 72-hr period for all of the regions from roughly 40 to 70 Mm. The smallest bipoles (<9 MSH) are outliers in that they do not obey Joy's law and have a much smaller footpoint separation. We confirm the Muñoz-Jaramillo et al. results that the sunspots appear to be two distinct populations

  6. Flexible fuel cycle initiative for the transition period from current reactors to next generation reactors

    International Nuclear Information System (INIS)

    Yamashita, Junichi; Fukasawa, Tetsuo; Hoshino, Kuniyoshi; Kawamura, Fumio; Shiina, Kouji; Sasahira, Akira

    2005-01-01

    A sustainable electricity supply by fast breeder reactors (FBRs) is essential to ensure energy security and prevent global warming. Transition from light water reactors (LWRs) to FBRs and establishment of an FBR cycle are indispensable, which requires plutonium (Pu) for the introduction of FBRs. The authors propose advanced system called 'Flexible Fuel Cycle Initiative (FFCI)' which can respond flexibly the future expected technical and social uncertainties, can hold no surplus Pu, and can achieve an economical FBR cycle. In the new concept of FFCI, 2nd LWR reprocessing which would succeed Rokkasho Reprocessing Plant is a simple facility to carry out only uranium (U) removal and residual 'recycle material' is stored or utilized. According to FBRs introduction status, recycle material is immediately treated in an FBR reprocessing to fabricate FBR fuel or temporarily stored for the utilization in FBRs at necessary timing. FFCI has high flexibility by having several options for future uncertainties by the introduction of recycle material as a buffer material between LWR and FBR cycles. (author)

  7. Transition period fuel cycle from current to next generation reactors for Japan

    International Nuclear Information System (INIS)

    Yamashita, Junichi; Fukasawa, Tetsuo; Hoshino, Kuniyoshi; Kawamura, Fumio; Shiina, Kouji; Sasahira, Akira

    2007-01-01

    Long-term energy security and global warming prevention can be achieved by a sustainable electricity supply with next generation fast breeder reactors (FBRs). Current light water reactors (LWRs) will be replaced by FBRs and FBR cycle will be established in the future considering the limited amount of uranium (U) resource. The introduction of FBRs requires plutonium (Pu) recovered from LWR spent fuel. The authors propose advanced system named Flexible Fuel Cycle Initiative (FFCI)' which can supply enough Pu and hold no surplus Pu, can respond flexibly the future technical and social uncertainties, and can achieve an economical FBR cycle. FFCI can simplify the 2nd LWR reprocessing facility for Japan (after Rokkasho Reprocessing Plant) which only carries out U removal from LWR spent fuel. Residual 'Recycle Material' is, according to FBRs introduction status, immediately treated in the FBR reprocessing to fabricate FBR fuel or temporarily stored for the utilization in FBRs at necessary timing. FFCI has high flexibility by having several options for future uncertainties by the introduction of Recycle Material as a buffer material between LWR and FBR cycles. (author)

  8. Sunspot Oscillations From The Chromosphere To The Corona

    Science.gov (United States)

    Brynildsen, N.; Maltby, P.; Fredvik, T.; Kjeldseth-Moe, O.

    The behavior of the 3 minute sunspot oscillations is studied as a function of temper- ature through the transition region using observations with CDS/SOHO and TRACE. The oscillations occur above the umbra, with amplitudes increasing to a maximum near 200 000 K, then decreasing towards higher temperatures. Deviations from pure linear oscillations are present in several cases. Power spectra of the oscillations are remarkably similar in the chromosphere and through the transition region in contra- diction to the predictions of the sunspot filter theory. The 3 minute oscillations pene- trate to the low temperature end of the corona, where they are channeled into smaller areas coinciding with the endpoints of sunspot coronal loops. This differs from the transition zone where the oscillating region covers the umbra.

  9. The Flares Associated with the Dynamics of the Sunspots K. M. ...

    Indian Academy of Sciences (India)

    tional theory of magnetic reconnection is briefly discussed. ... between changes in the sunspots' dynamics, emerging flux region, twisting of the field ... the eventual triggering of the flares is due to proper motion of the sunspots. Using .... rotation rates obtained from the daily motion of sunspot groups with respect to their life.

  10. Uncertainty and sensitivity analyses of ballast life-cycle cost and payback period

    OpenAIRE

    Mcmahon, James E.

    2000-01-01

    The paper introduces an innovative methology for evaluating the relative significance of energy-efficient technologies applied to fluorescent lamp ballasts. The method involves replacing the point estimates of life cycle cost of the ballasts with uncertainty distributions reflecting the whole spectrum of possible costs, and the assessed probability associated with each value. The results of uncertainty and sensitivity analyses will help analysts reduce effort in data collection and carry on a...

  11. A new look at sunspot formation using theory and observations

    Science.gov (United States)

    Losada, I. R.; Warnecke, J.; Glogowski, K.; Roth, M.; Brandenburg, A.; Kleeorin, N.; Rogachevskii, I.

    2017-10-01

    Sunspots are of basic interest in the study of the Sun. Their relevance ranges from them being an activity indicator of magnetic fields to being the place where coronal mass ejections and flares erupt. They are therefore also an important ingredient of space weather. Their formation, however, is still an unresolved problem in solar physics. Observations utilize just 2D surface information near the spot, but it is debatable how to infer deep structures and properties from local helioseismology. For a long time, it was believed that flux tubes rising from the bottom of the convection zone are the origin of the bipolar sunspot structure seen on the solar surface. However, this theory has been challenged, in particular recently by new surface observation, helioseismic inversions, and numerical models of convective dynamos. In this article we discuss another theoretical approach to the formation of sunspots: the negative effective magnetic pressure instability. This is a large-scale instability, in which the total (kinetic plus magnetic) turbulent pressure can be suppressed in the presence of a weak large-scale magnetic field, leading to a converging downflow, which eventually concentrates the magnetic field within it. Numerical simulations of forced stratified turbulence have been able to produce strong super-equipartition flux concentrations, similar to sunspots at the solar surface. In this framework, sunspots would only form close to the surface due to the instability constraints on stratification and rotation. Additionally, we present some ideas from local helioseismology, where we plan to use the Hankel analysis to study the pre-emergence phase of a sunspot and to constrain its deep structure and formation mechanism.

  12. Polar coronal holes and solar cycles

    International Nuclear Information System (INIS)

    Simon, P.A.

    1979-01-01

    The relationship between the geomagnetic activity of the three years preceding a sunspot minimum and the peak of the next sunspot maximum confirms the polar origin of the solar wind during one part of the solar cycle. Pointing out that the polar holes have a very small size or disappear at the time of the polar field reversal, a low latitude origin of the solar-wind at sunspot maximum is suggested and the cycle variation of solar wind and geomagnetic activity is described. In addition a close relationship is noted between the maximum level of the geomagnetic activity reached a few years before a solar minimum and its level at the next sunspot maximum. Studying separately the effects of both the low latitude holes and the solar activity, the possibility of predicting both the level of geomagnetic activity and the sunspot number at the next sunspot maximum is pointed out. As a conclusion the different categories of phenomena contributing to a solar cycle are specified. (Auth.)

  13. Sun-controlled spatial and time-dependent cycles in the climatic/weather system

    International Nuclear Information System (INIS)

    Njau, E.C.

    1990-11-01

    We show, on the basis of meteorological records, that certain spatial and time-dependent cycles exist in the earth-atmosphere system (EAS). These cycles seem to be associated with sunspot cycles and hence have been referred to in the text as ''data-derived solar cycles''. Our analysis establishes three important characteristics of the data-derived solar cycles (DSC's). Firstly the crests and troughs of these data-derived solar cycles are mostly latitudinally aligned and have (zonal) spatial wavelengths greater than about 7 degrees of longitude. Secondly the DSC's have periods mostly lying between 6 years and 12 years. In certain stations, some DSC's coincide quite well with corresponding sunspot cycles. Thirdly the crests and troughs of the DSC's drift eastwards at speeds exceeding about 1.5 longitude degrees per year. Furthermore, these DSC's display peak-to-peak amplitudes of about 2 deg. C along East Africa. On the basis of earlier work and bearing in mind the considerable temperature-dependence of the stratospheric ozone layer, we predict existence of latitudinally aligned enhancement and depletion structures (corresponding to the DSC's) in the stratospheric ozone layer within cloudless midnight-to-predawn sectors. (author). 9 refs, 5 figs

  14. Uncertainty and sensitivity analyses of ballast life-cycle cost and payback period

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, James E.; Liu, Xiaomin; Turiel, Ike; Hakim, Sajid; Fisher, Diane

    2000-06-01

    The paper introduces an innovative methodology for evaluating the relative significance of energy-efficient technologies applied to fluorescent lamp ballasts. The method involves replacing the point estimates of life cycle cost of the ballasts with uncertainty distributions reflecting the whole spectrum of possible costs, and the assessed probability associated with each value. The results of uncertainty and sensitivity analyses will help analysts reduce effort in data collection and carry on analysis more efficiently. These methods also enable policy makers to gain an insightful understanding of which efficient technology alternatives benefit or cost what fraction of consumers, given the explicit assumptions of the analysis.

  15. SOLAR VARIABILITY FROM 240 TO 1750 nm IN TERMS OF FACULAE BRIGHTENING AND SUNSPOT DARKENING FROM SCIAMACHY

    International Nuclear Information System (INIS)

    Pagaran, J.; Weber, M.; Burrows, J.

    2009-01-01

    The change of spectral decomposition of the total radiative output on various timescales of solar magnetic activity is of large interest to terrestrial and solar-stellar atmosphere studies. Starting in 2002, SCIAMACHY was the first satellite instrument to observe daily solar spectral irradiance (SSI) continuously from 230 nm (UV) to 1750 nm (near-infrared; near-IR). In order to address the question of how much UV, visible (vis), and IR spectral regions change on 27 day and 11 year timescales, we parameterize short-term SSI variations in terms of faculae brightening (Mg II index) and sunspot darkening (photometric sunspot index) proxies. Although spectral variations above 300 nm are below 1% and, therefore, well below the accuracy of absolute radiometric calibration, relative accuracy for short-term changes is shown to be in the per mill range. This enables us to derive short-term spectral irradiance variations from the UV to the near-IR. During Halloween solar storm in 2003 with a record high sunspot area, we observe a reduction of 0.3% in the near-IR to 0.5% in the vis and near-UV. This is consistent with a 0.4% reduction in total solar irradiance (TSI). Over an entire 11 year solar cycle, SSI variability covering simultaneously the UV, vis, and IR spectral regions have not been directly observed so far. Using variations of solar proxies over solar cycle 23, solar cycle spectral variations have been estimated using scaling factors that best matched short-term variations of SCIAMACHY. In the 300-400 nm region, which strongly contributes to TSI solar cycle change, a contribution of 34% is derived from SCIAMACHY observations, which is lower than the reported values from SUSIM satellite data and the empirical SATIRE model. The total UV contribution (below 400 nm) to TSI solar cycle variations is estimated to be 55%.

  16. Long-period variations of wind parameters in the mesopause region and the solar cycle dependence

    International Nuclear Information System (INIS)

    Greisiger, K.M.; Schminder, R.; Kuerschner, D.

    1987-01-01

    The solar cycle dependence of wind parameters below 100 km on the basis of long term continuous ionospheric drift measurements in the low frequency range is discussed. For the meridional prevailing wind no significant variation was found. The same comparison as for winter was done for summer where the previous investigations gave no correlation. Now the radar meteor wind measurement values, too, showed a significant negative correlation of the zonal prevailing wind with solar activity for the years 1976 to 1983. The ionospheric drift measurement results of Collm have the same tendency but a larger dispersion due to the lower accuracy of the harmonic analysis because of the shorter daily measuring interval in summer. Continuous wind observations in the upper mesopause region over more than 20 years revealed distinct long term variations, the origin of which cannot be explained with the present knowledge

  17. HELIOSEISMIC HOLOGRAPHY OF SIMULATED SUNSPOTS: MAGNETIC AND THERMAL CONTRIBUTIONS TO TRAVEL TIMES

    Energy Technology Data Exchange (ETDEWEB)

    Felipe, T. [Departamento de Astrofísica, Universidad de La Laguna, E-38205 La Laguna, Tenerife (Spain); Braun, D. C.; Crouch, A. D. [NorthWest Research Associates, Colorado Research Associates, Boulder, CO 80301 (United States); Birch, A. C., E-mail: tobias@iac.es [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2016-10-01

    Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that of the quiet Sun. As a consequence, the interpretation of local helioseismic measurements of sunspots has long been a challenge. With the aim of understanding these measurements, we carry out numerical simulations of wave propagation through sunspots. Helioseismic holography measurements made from the resulting simulated wavefields show qualitative agreement with observations of real sunspots. We use additional numerical experiments to determine, separately, the influence of the thermal structure of the sunspot and the direct effect of the sunspot magnetic field. We use the ray approximation to show that the travel-time shifts in the thermal (non-magnetic) sunspot model are primarily produced by changes in the wave path due to the Wilson depression rather than variations in the wave speed. This shows that inversions for the subsurface structure of sunspots must account for local changes in the density. In some ranges of horizontal phase speed and frequency there is agreement (within the noise level in the simulations) between the travel times measured in the full magnetic sunspot model and the thermal model. If this conclusion proves to be robust for a wide range of models, it would suggest a path toward inversions for sunspot structure.

  18. HELIOSEISMIC HOLOGRAPHY OF SIMULATED SUNSPOTS: MAGNETIC AND THERMAL CONTRIBUTIONS TO TRAVEL TIMES

    International Nuclear Information System (INIS)

    Felipe, T.; Braun, D. C.; Crouch, A. D.; Birch, A. C.

    2016-01-01

    Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that of the quiet Sun. As a consequence, the interpretation of local helioseismic measurements of sunspots has long been a challenge. With the aim of understanding these measurements, we carry out numerical simulations of wave propagation through sunspots. Helioseismic holography measurements made from the resulting simulated wavefields show qualitative agreement with observations of real sunspots. We use additional numerical experiments to determine, separately, the influence of the thermal structure of the sunspot and the direct effect of the sunspot magnetic field. We use the ray approximation to show that the travel-time shifts in the thermal (non-magnetic) sunspot model are primarily produced by changes in the wave path due to the Wilson depression rather than variations in the wave speed. This shows that inversions for the subsurface structure of sunspots must account for local changes in the density. In some ranges of horizontal phase speed and frequency there is agreement (within the noise level in the simulations) between the travel times measured in the full magnetic sunspot model and the thermal model. If this conclusion proves to be robust for a wide range of models, it would suggest a path toward inversions for sunspot structure.

  19. Automated Sunspot Detection and Classification Using SOHO/MDI Imagery

    Science.gov (United States)

    2015-03-01

    to the geocentric North). 3. Focus and size of the solar disk is adjusted to fit an 18 cm diameter circle on the worksheet. 4. Analyst hand draws the...General Nature of the Sunspot,” The Astrophysical Journal 230, 905–913 (1979). 14. Wheatland, M. S., “A Bayesian Approach to Solar Flare Prediction,” The

  20. 3-color photometry of a sunspot using speckle masking techniques

    NARCIS (Netherlands)

    Wiehr, E.; Sütterlin, P.

    1998-01-01

    A three-colour photometry is used to deduce the temperature of sunspot fine-structures. Using the Speckle-Masking method for image restoration, the resulting images (one per colour and burst) have a spatial resolution only limited by the telescope's aperture, i.e. 95km (blue), 145 km (red) and

  1. Duty cycle dependence of a periodically poled LiNbO3-based electro-optic Solc filter.

    Science.gov (United States)

    Rabia, Eyal; Arie, Ady

    2006-01-20

    We demonstrate that the performance of a periodically poled LiNbO3- (PPLN-) based electro-optic Solc filter is dependent on the duty cycle of the crystal. This may limit the performance of the device for applications such as add-drop filtering and switching, owing to the deterioration of the extinction ratio. It is shown that by adding a retarder to the Solc filter it is possible to improve the extinction ratio; thus the dependence of the filter on the duty cycle can be reduced. Using Jones calculus, we analyzed the effect of a variable retarder that can also be rotated on the extinction ratio. We experimentally observed a 6 dB increase in the extinction ratio when we used a half-wavelength retarder.

  2. Long-period Intensity Pulsations in Coronal Loops Explained by Thermal Non-equilibrium Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Froment, C.; Auchère, F.; Bocchialini, K.; Buchlin, E.; Solomon, J. [Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bât. 121, F-91405 Orsay cedex (France); Aulanier, G. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); Mikić, Z., E-mail: clara.froment@astro.uio.no [Predictive Science, Inc., San Diego, CA 92121 (United States)

    2017-02-01

    In solar coronal loops, thermal non-equilibrium (TNE) is a phenomenon that can occur when the heating is both highly stratified and quasi-constant. Unambiguous observational identification of TNE would thus permit us to strongly constrain heating scenarios. While TNE is currently the standard interpretation of coronal rain, the long-term periodic evolution predicted by simulations has never been observed. However, the detection of long-period intensity pulsations (periods of several hours) has been recently reported with the Solar and Heliospheric Observatory /EIT, and this phenomenon appears to be very common in loops. Moreover, the three intensity-pulsation events that we recently studied with the Solar Dynamics Observatory /Atmospheric Imaging Assembly (AIA) show strong evidence for TNE in warm loops. In this paper, a realistic loop geometry from linear force-free field (LFFF) extrapolations is used as input to 1D hydrodynamic simulations. Our simulations show that, for the present loop geometry, the heating has to be asymmetrical to produce TNE. We analyze in detail one particular simulation that reproduces the average thermal behavior of one of the pulsating loop bundle observed with AIA. We compare the properties of this simulation with those deduced from the observations. The magnetic topology of the LFFF extrapolations points to the presence of sites of preferred reconnection at one footpoint, supporting the presence of asymmetric heating. In addition, we can reproduce the temporal large-scale intensity properties of the pulsating loops. This simulation further strengthens the interpretation of the observed pulsations as signatures of TNE. This consequently provides important information on the heating localization and timescale for these loops.

  3. Characterization and consequences from CEA nuclear fuel cycle facilities effluents releases - 1995 up to 2007 period

    International Nuclear Information System (INIS)

    Ferreira, Nelson Luiz Dias; Fonseca, Lizandra Pereira de Souza

    2009-01-01

    Discharges to the environment of airborne and/or liquid radioactive effluents from the normal operation of nuclear facilities can become a potential source of radiation exposure to humans. The highest exposed members of the public are defined as the critical group. The requirements for the control and monitoring of radioactive discharges to the environment and the degree of environmental monitoring required are linked to the assessed critical group dose. The assessed dose can be compared to dose constraint, which is a fraction of the annual effective dose to members of the public, as well as the level of exemption specified by the National Commission for Nuclear Energy (CNEN). Effluents releases from the Centro Experimental Aramar (CEA) facilities are registered and described at CEA Effluent Report, semestrally sent to CNEN. Basically, that report provides information related to the type and the quantity of chemical and radioactive substances released to the environment due the routine operation of CEA nuclear fuel cycle facilities (LEI - Isotopic Enrichment Laboratory, USIDE - Pilot Plant for Industrial Verification of Uranium Enrichment and LABMAT - Nuclear Materials Laboratory). CEA Annual Effluent Report includes assessment of the annual effective doses for members of the critical group for the CEA site. This work presents the characterization of the radioactive release source terms and a historical of the critical group annual doses from 1995 up to 2007. (author)

  4. Marine methane cycle simulations for the period of early global warming

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, S.; Maltrud, M.; Reagan, M.T.; Moridis, G.J.; Cameron-Smith, P.J.

    2011-01-02

    Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH{sub 4} distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

  5. Marine methane cycle simulations for the period of early global warming

    Science.gov (United States)

    Elliott, Scott; Maltrud, Mathew; Reagan, Matthew; Moridis, George; Cameron-Smith, Philip

    2011-03-01

    Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH4 distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

  6. Long-period variations of wind parameters in the mesopause region and the solar cycle dependence

    International Nuclear Information System (INIS)

    Greisiger, K.M.; Schminder, R.; Kuerschner, D.

    1987-01-01

    A solar dependence of wind parameters below 100 km was found by Sprenger and Schminder on the basis of long-term continuous ionospheric drift measurements. For winter they obtained for the prevailing wind a positive correlation with solar activity and for the amplitude of the semi-diurnal tidal wind a negative correlation. However, after the years 1973-1974 we found a significant negative correlation with solar activity with an indication of a new change after 1983. We conclude that this long-term behaviour points rather to a climatic variation with an internal atmospheric cause than to a direct solar control. Recent satellite data of the solar u.v. radiation and the upper stratospheric ozone have shown that the possible variation of the thermal tidal excitation during the solar cycle amounts to only a few per cent. This is, therefore, insufficient to account for the 40-70% variation of the tidal amplitudes. Some other possibilities of explaining this result are discussed. (author)

  7. Variations in steroid hormone receptor content throughout age and menopausal periods, and menstrual cycle in breast cancer patients

    International Nuclear Information System (INIS)

    Nikolic-Vukosavljevic, D.; Vasiljevic, N.; Brankovic-Magic, M.; Polic, D.

    1996-01-01

    Variations in steroid hormone receptor contents throughout age and menopausal periods define three breast carcinoma groups: younger pre-menopausal carcinomas (aged up to 45), middle-aged carcinomas (aged up to 45), middle-aged carcinomas (pre-, peri-, and postmenopausal aged 45-59) and older postmenopausal carcinomas (aged over 59). Age-related steroid hormone receptor contents within pre-menopausal and postmenopausal carcinoma groups are characterized by the important increase of both receptor contents, while menopausal-related steroid hormone receptor contents within middle-aged carcinoma group (aged 45-59) are characterized by the important decrease of progesterone receptor content and estrogen receptor functionality. No variations in steroid hormone receptor contents throughout menstrual cycle within the follicular and the luteal phases were obtained. The important cycle within the follicular and the luteal phases were obtained. The important decrease of estrogen receptor content in the mid-cycle phase versus the peri-menstrual phase was found. Variations in steroid hormone receptor contents throughout age and menopausal periods, as well as throughout menstrual cycle could nod be associated with variations in the blood steroid hormone concentrations. However, important association between steroid hormone receptor contents and the blood steroid hormone concentrations was found within the luteal phase carcinoma group and within older postmenopausal carcinoma group. It is interesting that within carcinoma group with the highest concentration of progesterone, progesterone receptor content increases with an increase of the ration of estradiol and progesterone blood concentrations, while within carcinoma group with the lowest steroid hormone concentration and the highest content of estrogen receptor content, estrogen receptor content decreases with an increase of either the blood estradiol concentration or the ratio of the blood estradiol and progesterone blood

  8. [Effects of reversing the feeding cycle and the light period on the spontaneous activity of the rat (author's transl)].

    Science.gov (United States)

    Ticca, M

    1976-01-01

    The amount and the circadian distribution of spontaneous activity in the rat are influenced by a number of factors, whose importance and interrelationships are still deeply discussed. In order to check the reliability of previous studies about the effects of meal-eating on the spontaneous activity (wheel running) of rats of our Sprague-Dawley strain, the adjustment to the modifications of the normal day-night cycle and of the normal nocturnal feeding rhythm have been controlled. Reversing the normal light and dark periods caused the rats, after a 24 hours period, to lower and to irregularly distribute their spontaneous activity. Rats shifted their pattern of maximal activity by 12 hours in the new period of darkness in about five days, and showed to have completely fixed the new reversed running habit. Also feeding habits changed in a similar way, but more slowly. The levels of mean daily activity did not change. In a second experiment, rats, received food during light hours, and were deprived during dark hours. Their activity increased considerably and irregularly during dark hours, while a very slight rise of wheel running was shown during light hours. Body weight gain and food consumption were similar to those of the control group. These results slightly differ from those obtained using other rat strains, and are an interesting example of reinforcement of a spontaneous behavior resulting more from the light-dark cycle than from cues provided by food deprivation.

  9. Period doubling cascades of limit cycles in cardiac action potential models as precursors to chaotic early Afterdepolarizations.

    Science.gov (United States)

    Kügler, Philipp; Bulelzai, M A K; Erhardt, André H

    2017-04-04

    Early afterdepolarizations (EADs) are pathological voltage oscillations during the repolarization phase of cardiac action potentials (APs). EADs are caused by drugs, oxidative stress or ion channel disease, and they are considered as potential precursors to cardiac arrhythmias in recent attempts to redefine the cardiac drug safety paradigm. The irregular behaviour of EADs observed in experiments has been previously attributed to chaotic EAD dynamics under periodic pacing, made possible by a homoclinic bifurcation in the fast subsystem of the deterministic AP system of differential equations. In this article we demonstrate that a homoclinic bifurcation in the fast subsystem of the action potential model is neither a necessary nor a sufficient condition for the genesis of chaotic EADs. We rather argue that a cascade of period doubling (PD) bifurcations of limit cycles in the full AP system paves the way to chaotic EAD dynamics across a variety of models including a) periodically paced and spontaneously active cardiomyocytes, b) periodically paced and non-active cardiomyocytes as well as c) unpaced and spontaneously active cardiomyocytes. Furthermore, our bifurcation analysis reveals that chaotic EAD dynamics may coexist in a stable manner with fully regular AP dynamics, where only the initial conditions decide which type of dynamics is displayed. EADs are a potential source of cardiac arrhythmias and hence are of relevance both from the viewpoint of drug cardiotoxicity testing and the treatment of cardiomyopathies. The model-independent association of chaotic EADs with period doubling cascades of limit cycles introduced in this article opens novel opportunities to study chaotic EADs by means of bifurcation control theory and inverse bifurcation analysis. Furthermore, our results may shed new light on the synchronization and propagation of chaotic EADs in homogeneous and heterogeneous multicellular and cardiac tissue preparations.

  10. Distribution of (14 C) photosynthates in 3 periods during the plant-cane cycle

    International Nuclear Information System (INIS)

    Pimentel, R.M.M.

    1989-04-01

    Plant-cane stools were labelled with 14 CO 2 in the field, at Goiana-PE, Brazil, when 3,7 and 11 months old. Each stool was enclosed in a chamber with 14 CO 2 for 90 minutes. The 14 C photosynthates were measured in leaves, stalks, roots and soil 1, 7, 15, 30, 60 and 90 days after labelling. Roots were divided into alive and dead and soil into rizosphere and outer soil. The soil was incubated for 10 days to measure C mineralization. At end of the labelling period at 3,7 and 11 months, 2, 19 and 1% of the initial 14 CO 2 were recovered in the plant and the soil. The low recovery of 14 C at 3 months could be attributed to losses by respiration and lack of sampling of the top growing point. The low CO 2 fixation and losses by respiration at first sampling in the 7 months old labelling were attributed to low light intensity during the day of labelling. In the following sampling, total 14 C recoveries varied little and there was little change in the proportion of 14 C in each part, indicating that the 14 C was already incorporated in stable organic fractions. Most of the recovered 14 C C>80%) was founded in the leaves but all plant parts received labelled photosynthates. (author)

  11. The evolution of the Gutenberg-Richter, b-value, throughout periodic and aperiodic stick-slip cycles

    Science.gov (United States)

    Bolton, D. C.; Riviere, J.; Marone, C.; Johnson, P. A.

    2017-12-01

    The Gutenberg-Richter earthquake size statistic, b value, is a useful proxy for documenting the state of stress on a fault and understanding precursory phenomena preceding dynamic failure. It has been shown that the b value varies systematically as a function of position within the seismic cycle. Frictional studies on intact rock samples with saw-cut faults have shown that b value decreases continuously preceding failure. For intact rock samples, the spatiotemporal changes in b value are thought to be related to the evolution of asperities and micro-cracks. However, few studies have shown how b value evolves spatially and temporally for fault zones containing gouge and wear materials. We hypothesize that the micromechanical mechanisms acting within fault gouge, such as creation and destruction of force chains, grain rolling, sliding, jamming and fracturing play an important role in the evolution of b value and that they may have distinct signatures during periodic and aperiodic cycles of stick-slip frictional motion. We report results from experiments conducted on simulated fault gouge using a biaxial deformation apparatus in a double-direct shear configuration. Acoustic emissions (AEs) are recorded at 4 MHz from 36 P-polarized piezoelectric transducers, which are embedded in steel blocks located adjacent to the fault zone. We compute the frequency-magnitude distribution of detected AEs using a moving window in events where each window is overlapped by 75%. We report on the evolution of b value as a function of normal stress and gouge layer thickness. For periodic slip events, b value reaches a maximum value immediately after a slip event and decreases continuously until the next failure. Aperiodic slip events show similar trends in b-value initially, however unlike periodic slip events, b value reaches a steady state value before failure occurs. In addition, for periodic slip events the magnitude of the change in b value scales inversely with gouge layer thickness

  12. WAVES AS THE SOURCE OF APPARENT TWISTING MOTIONS IN SUNSPOT PENUMBRAE

    International Nuclear Information System (INIS)

    Bharti, L.; Cameron, R. H.; Hirzberger, J.; Solanki, S. K.; Rempel, M.

    2012-01-01

    The motion of dark striations across bright filaments in a sunspot penumbra has become an important new diagnostic of convective gas flows in penumbral filaments. The nature of these striations has, however, remained unclear. Here, we present an analysis of small-scale motions in penumbral filaments in both simulations and observations. The simulations, when viewed from above, show fine structure with dark lanes running outward from the dark core of the penumbral filaments. The dark lanes either occur preferentially on one side or alternate between both sides of the filament. We identify this fine structure with transverse (kink) oscillations of the filament, corresponding to a sideways swaying of the filament. These oscillations have periods in the range of 5-7 minutes and propagate outward and downward along the filament. Similar features are found in observed G-band intensity time series of penumbral filaments in a sunspot located near disk center obtained by the Broadband Filter Imager on board the Hinode. We also find that some filaments show dark striations moving to both sides of the filaments. Based on the agreement between simulations and observations we conclude that the motions of these striations are caused by transverse oscillations of the underlying bright filaments.

  13. The mutual attraction of magnetic knots. [solar hydromagnetic instability in sunspot regions

    Science.gov (United States)

    Parker, E. N.

    1978-01-01

    It is observed that the magnetic knots associated with active regions on the sun have an attraction for each other during the formative period of the active regions, when new magnetic flux is coming to the surface. The attraction disappears when new flux ceases to rise through the surface. Then the magnetic spots and knots tend to come apart, leading to disintegration of the sunspots previously formed. The dissolution of the fields is to be expected, as a consequence of the magnetic repulsion of knots of like polarity and as a consequence of the hydromagnetic exchange instability. The purpose of this paper is to show that the mutual attraction of knots during the formative stages of a sunspot region may be understood as the mutual hydrodynamic attraction of the rising flux tubes. Two rising tubes attract each other, as a consequence of the wake of the leading tube when one is moving behind the other, and as a consequence of the Bernoulli effect when rising side by side.

  14. Initial phase of the development of sunspot groups and their forecast

    International Nuclear Information System (INIS)

    Berlyand, B.O.; Burov, V.A.; Stepanyan, N.N.

    1979-01-01

    Some characteristics of the initial phase of sunspot groups and their forecast have been considered. Experimental data on 340 sunspot groups were obtained in 1967-1969. It was found that oscillations of the magnetic flux in the groups indicate the possibility of the existence of typical periods (2 and 4 days) of the magnetic field development. Most of the groups appears in young plages. The probability of the protons injection from the young groups is very small. The typical time of the development of the proton centre is 10-30 days. The characteristics of the group on the first day of its existence are vaguely connected with the lifetime of the group. On the second and third days the magnetic characteristics (the summary magnetic flux and the number of the unipolar regions) have the highest correlation coefficient (approximately 70%) with the lifetime of the group. The problem of the group lifetime forecast was being solved with the pattern recognition technique. On the base of the second day observation of the existence of the group verification of the received forecast 14% exceeds the verification of the climatological forecast. The forecast of the Zurich class with the same technique is effective beginning with the fifth day of the group existence and the forecast of the flare activity of the group since the day of its appearance. The exceeding of the verification as compared with the climatological forecasts in these problems is 10% and 8% accordingly

  15. On the correlation of longitudinal and latitudinal motions of sunspots

    International Nuclear Information System (INIS)

    Gilman, P.A.

    1984-01-01

    Using new measurements of positions of individual sunspots and sunspot groups obtained from 62 years of the Mt. Wilson white-light plate collection, we have recomputed the correlation between longitude and latitude motion. Our results for groups are similar to those of Ward (1965a) computed from the Greenwich record, but for individual spots the covariance is reduced by a factor of about 3 from the Ward values, though still of the same sign and still statistically significant. We conclude that there is a real correlation between longitude and latitude movement of individual spots, implying angular momentum transport toward the equator as inferred by Ward. The two thirds reduction in the covariance for individual spots as opposed to groups is probably due to certain properties of spot groups, as first pointed out in an unpublished manuscript by Leighton. (orig.)

  16. Molecular Diagnostics of the Internal Structure of Starspots and Sunspots

    Science.gov (United States)

    Afram, N.; Berdyugina, S. V.; Fluri, D. M.; Solanki, S. K.; Lagg, A.; Petit, P.; Arnaud, J.

    2006-12-01

    We have analyzed the usefulness of molecules as a diagnostic tool for studying solar and stellar magnetism with the molecular Zeeman and Paschen-Back effects. In the first part we concentrate on molecules that are observed in sunspots such as MgH and TiO. We present calculated molecular line profiles obtained by assuming magnetic fields of 2-3 kG and compare these synthetic Stokes profiles with spectro-polarimetric observations in sunspots. The good agreement between the theory and observations allows us to turn our attention in the second part to starspots to gain insight into their internal structure. We investigate the temperature range in which the selected molecules can serve as indicators for magnetic fields on highly active cool stars and compare synthetic Stokes profiles with our recent observations.

  17. Studies of kinematic elements in two multicenter sunspot groups

    International Nuclear Information System (INIS)

    Korobova, Z.B.

    1983-01-01

    Some features of kinematic elements (KE) in two multicenter sunspot groups were studied using Tashkent full-disc white light heliograms. KE and morphological elements do not reveal any relationship. A KE coincides with a unipolar or multipolar spot or with part of a spot. It may also contain an extended stream including several spots. Relation of KE to large-scale photospheric magnetic fields is less clear. The line of polarity reversal is, in most cases, the deviding line between two adjacent KE. At the same time, a KE can contain spots of both polarities. Sunspot trajectories in the leading polarity regions show the best similarity. Interactions of KE are greatly influenced by the meridional drift. (author)

  18. The Temperature - Magnetic Field Relation in Observed and Simulated Sunspots

    Czech Academy of Sciences Publication Activity Database

    Sobotka, Michal; Rezaei, R.

    2017-01-01

    Roč. 292, č. 12 (2017), 188/1-188/12 ISSN 0038-0938 R&D Projects: GA ČR(CZ) GA14-04338S; GA MŠk(CZ) 7E13003 EU Projects: European Commission(XE) 312495 - SOLARNET Institutional support: RVO:67985815 Keywords : sunspots * magnetic fields * comparison Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.682, year: 2016

  19. SPECTROPOLARIMETRICALLY ACCURATE MAGNETOHYDROSTATIC SUNSPOT MODEL FOR FORWARD MODELING IN HELIOSEISMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Przybylski, D.; Shelyag, S.; Cally, P. S. [Monash Center for Astrophysics, School of Mathematical Sciences, Monash University, Clayton, Victoria 3800 (Australia)

    2015-07-01

    We present a technique to construct a spectropolarimetrically accurate magnetohydrostatic model of a large-scale solar magnetic field concentration, mimicking a sunspot. Using the constructed model we perform a simulation of acoustic wave propagation, conversion, and absorption in the solar interior and photosphere with the sunspot embedded into it. With the 6173 Å magnetically sensitive photospheric absorption line of neutral iron, we calculate observable quantities such as continuum intensities, Doppler velocities, as well as the full Stokes vector for the simulation at various positions at the solar disk, and analyze the influence of non-locality of radiative transport in the solar photosphere on helioseismic measurements. Bisector shapes were used to perform multi-height observations. The differences in acoustic power at different heights within the line formation region at different positions at the solar disk were simulated and characterized. An increase in acoustic power in the simulated observations of the sunspot umbra away from the solar disk center was confirmed as the slow magnetoacoustic wave.

  20. SPECTROPOLARIMETRICALLY ACCURATE MAGNETOHYDROSTATIC SUNSPOT MODEL FOR FORWARD MODELING IN HELIOSEISMOLOGY

    International Nuclear Information System (INIS)

    Przybylski, D.; Shelyag, S.; Cally, P. S.

    2015-01-01

    We present a technique to construct a spectropolarimetrically accurate magnetohydrostatic model of a large-scale solar magnetic field concentration, mimicking a sunspot. Using the constructed model we perform a simulation of acoustic wave propagation, conversion, and absorption in the solar interior and photosphere with the sunspot embedded into it. With the 6173 Å magnetically sensitive photospheric absorption line of neutral iron, we calculate observable quantities such as continuum intensities, Doppler velocities, as well as the full Stokes vector for the simulation at various positions at the solar disk, and analyze the influence of non-locality of radiative transport in the solar photosphere on helioseismic measurements. Bisector shapes were used to perform multi-height observations. The differences in acoustic power at different heights within the line formation region at different positions at the solar disk were simulated and characterized. An increase in acoustic power in the simulated observations of the sunspot umbra away from the solar disk center was confirmed as the slow magnetoacoustic wave

  1. Photospheric Origin of Three-minute Oscillations in a Sunspot

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Jongchul; Lee, Jeongwoo; Cho, Kyuhyoun; Song, Donguk [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Cho, Kyungsuk; Yurchyshyn, Vasyl [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of)

    2017-02-10

    The origin of the three-minute oscillations of intensity and velocity observed in the chromosphere of sunspot umbrae is still unclear. We investigated the spatio-spectral properties of the 3 minute oscillations of velocity in the photosphere of a sunspot umbra as well as those in the low chromosphere using the spectral data of the Ni i λ 5436, Fe i λ 5435, and Na i D{sub 2} λ 5890 lines taken by the Fast Imaging Solar Spectrograph of the 1.6 m New Solar Telescope at the Big Bear Solar Observatory. As a result, we found a local enhancement of the 3 minute oscillation power in the vicinities of a light bridge (LB) and numerous umbral dots (UDs) in the photosphere. These 3 minute oscillations occurred independently of the 5 minute oscillations. Through wavelet analysis, we determined the amplitudes and phases of the 3 minute oscillations at the formation heights of the spectral lines, and they were found to be consistent with the upwardly propagating slow magnetoacoustic waves in the photosphere with energy flux large enough to explain the chromospheric oscillations. Our results suggest that the 3 minute chromospheric oscillations in this sunspot may have been generated by magnetoconvection occurring in the LB and UDs.

  2. Frequently Occurring Reconnection Jets from Sunspot Light Bridges

    Science.gov (United States)

    Tian, Hui; Yurchyshyn, Vasyl; Peter, Hardi; Solanki, Sami K.; Young, Peter R.; Ni, Lei; Cao, Wenda; Ji, Kaifan; Zhu, Yingjie; Zhang, Jingwen; Samanta, Tanmoy; Song, Yongliang; He, Jiansen; Wang, Linghua; Chen, Yajie

    2018-02-01

    Solid evidence of magnetic reconnection is rarely reported within sunspots, the darkest regions with the strongest magnetic fields and lowest temperatures in the solar atmosphere. Using the world’s largest solar telescope, the 1.6 m Goode Solar Telescope, we detect prevalent reconnection through frequently occurring fine-scale jets in the Hα line wings at light bridges, the bright lanes that may divide the dark sunspot core into multiple parts. Many jets have an inverted Y-shape, shown by models to be typical of reconnection in a unipolar field environment. Simultaneous spectral imaging data from the Interface Region Imaging Spectrograph show that the reconnection drives bidirectional flows up to 200 km s‑1, and that the weakly ionized plasma is heated by at least an order of magnitude up to ∼80,000 K. Such highly dynamic reconnection jets and efficient heating should be properly accounted for in future modeling efforts of sunspots. Our observations also reveal that the surge-like activity previously reported above light bridges in some chromospheric passbands such as the Hα core has two components: the ever-present short surges likely to be related to the upward leakage of magnetoacoustic waves from the photosphere, and the occasionally occurring long and fast surges that are obviously caused by the intermittent reconnection jets.

  3. MODELING THE CHROMOSPHERE OF A SUNSPOT AND THE QUIET SUN

    Energy Technology Data Exchange (ETDEWEB)

    Avrett, E.; Tian, H. [Smithsonian Astrophysical Observatory, Cambridge, MA 02138 (United States); Landi, E. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Curdt, W. [Max Planck Institut für Sonnensystemfoschung, Goettingen (Germany); Wülser, J.-P. [Lockheed Martin Advanced Techonology Center (United States)

    2015-10-01

    Semiempirical atmospheric modeling attempts to match an observed spectrum by finding the temperature distribution and other physical parameters along the line of sight through the emitting region such that the calculated spectrum agrees with the observed one. In this paper we take the observed spectrum of a sunspot and the quiet Sun in the EUV wavelength range 668–1475 Å from the 2001 SUMER atlas of Curdt et al. to determine models of the two atmospheric regions, extending from the photosphere through the overlying chromosphere into the transition region. We solve the coupled statistical equilibrium and optically thick radiative transfer equations for a set of 32 atoms and ions. The atoms that are part of molecules are treated separately, and are excluded from the atomic abundances and atomic opacities. We compare the Mg ii k line profile observations from the Interface Region Imaging Spectrograph with the profiles calculated from the two models. The calculated profiles for the sunspot are substantially lower than the observed ones, based on the SUMER models. The only way we have found to raise the calculated Mg ii lines to agree with the observations is to introduce illumination of the sunspot from the surrounding active region.

  4. The Relative Phase Asynchronization between Sunspot Numbers ...

    Indian Academy of Sciences (India)

    of Sciences, P. O. Box 110, 650011 Kunming, People's Republic of China. ... by studying the North–South asymmetry in the predominant rotation periods of ... earth, the polar faculae counts show strong annual variation, and the polar region is.

  5. Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

    Science.gov (United States)

    Koyama, T; Ito, H; Kakishima, S; Yoshimura, J; Cooley, J R; Simon, C; Sota, T

    2015-06-01

    Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  6. Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process.

    Science.gov (United States)

    Laranjeiro, Ricardo; Tamai, T Katherine; Letton, William; Hamilton, Noémie; Whitmore, David

    2018-04-01

    Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles.

  7. New reconstruction of the sunspot group numbers since 1739 using direct calibration and "backbone" methods

    Science.gov (United States)

    Chatzistergos, Theodosios; Usoskin, Ilya G.; Kovaltsov, Gennady A.; Krivova, Natalie A.; Solanki, Sami K.

    2017-06-01

    Context. The group sunspot number (GSN) series constitute the longest instrumental astronomical database providing information on solar activity. This database is a compilation of observations by many individual observers, and their inter-calibration has usually been performed using linear rescaling. There are multiple published series that show different long-term trends for solar activity. Aims: We aim at producing a GSN series, with a non-linear non-parametric calibration. The only underlying assumptions are that the differences between the various series are due to different acuity thresholds of the observers, and that the threshold of each observer remains constant throughout the observing period. Methods: We used a daisy chain process with backbone (BB) observers and calibrated all overlapping observers to them. We performed the calibration of each individual observer with a probability distribution function (PDF) matrix constructed considering all daily values for the overlapping period with the BB. The calibration of the BBs was carried out in a similar manner. The final series was constructed by merging different BB series. We modelled the propagation of errors straightforwardly with Monte Carlo simulations. A potential bias due to the selection of BBs was investigated and the effect was shown to lie within the 1σ interval of the produced series. The exact selection of the reference period was shown to have a rather small effect on our calibration as well. Results: The final series extends back to 1739 and includes data from 314 observers. This series suggests moderate activity during the 18th and 19th century, which is significantly lower than the high level of solar activity predicted by other recent reconstructions applying linear regressions. Conclusions: The new series provides a robust reconstruction, based on modern and non-parametric methods, of sunspot group numbers since 1739, and it confirms the existence of the modern grand maximum of solar

  8. Limit Cycles and Chaos via Quasi-periodicity in Two Coupled Ensembles of Ultra-cold Atoms.

    Science.gov (United States)

    Patra, Aniket; Yuzbashyan, Emil; Altshuler, Boris

    We study the dynamics of two mesoscopic ensembles of ultra-cold two level atoms, which are collectively coupled to an optical cavity and are being pumped incoherently to the excited state. Whereas the time independent steady states are well understood, little is known about the time dependent ones. We explore and categorize various time dependent steady states, e.g. limit cycles and chaotic behavior. We draw a non-equilibrium phase diagram indicating different steady-state behaviors in different parts of the parameter space. We discuss the synchronization of the two ensembles in the time dependent steady states. We also show the onset of chaos via quasi-periodicity. The rich time dependent steady-state behavior, especially the existence of chaos, opens up possibilities for several engineering applications. Supported in part by the University and Louis Bevier Graduate Fellowship.

  9. A Reanalysis for the Seasonal and Longer-Period Cycles and the Trends in Middle Atmosphere Temperature from the HALOE

    Science.gov (United States)

    Remsberg, Ellis E.

    2007-01-01

    Previously published analyses for the seasonal and longer-period cycles in middle atmosphere temperature versus pressure (or T(p)) from the Halogen Occultation Experiment (HALOE) are extended to just over 14 years and updated to properly account for the effects of autocorrelation in its time series of zonally-averaged data. The updated seasonal terms and annual averages are provided, and they can be used to generate temperature distributions that are representative of the period 1991-2005. QBO-like terms have also been resolved and are provided, and they exhibit good consistency across the range of latitudes and pressure-altitudes. Further, exploratory analyses of the residuals from each of the 221 time series have yielded significant 11-yr solar cycle (or SC-like) and linear trend terms at a number of latitudes and levels. The amplitudes of the SC-like terms for the upper mesosphere agree reasonably with calculations of the direct solar radiative effects for T(p). Those SC amplitudes increase by about a factor of 2 from the lower to the upper mesosphere and are also larger at the middle than at the low latitudes. The diagnosed cooling trends for the subtropical latitudes are in the range, -0.5 to -1.0 K/decade, which is in good agreement with the findings from models of the radiative effects on pressure surfaces due to known increases in atmospheric CO2. The diagnosed trends are somewhat larger than predicted with models for the upper mesosphere of the northern hemisphere middle latitudes.

  10. Prediction on sunspot activity based on fuzzy information granulation and support vector machine

    Science.gov (United States)

    Peng, Lingling; Yan, Haisheng; Yang, Zhigang

    2018-04-01

    In order to analyze the range of sunspots, a combined prediction method of forecasting the fluctuation range of sunspots based on fuzzy information granulation (FIG) and support vector machine (SVM) was put forward. Firstly, employing the FIG to granulate sample data and extract va)alid information of each window, namely the minimum value, the general average value and the maximum value of each window. Secondly, forecasting model is built respectively with SVM and then cross method is used to optimize these parameters. Finally, the fluctuation range of sunspots is forecasted with the optimized SVM model. Case study demonstrates that the model have high accuracy and can effectively predict the fluctuation of sunspots.

  11. Annual cycle solar energy utilization with seasonal storage. Part 8. Study on periodic steady state of the annual cycle energy system at a practical operation; Kisetsukan chikunetsu ni yoru nenkan cycle taiyo energy riyo system ni kansuru kenkyu. 8

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H; Okumiya, M [Nagoya University, Nagoya (Japan)

    1997-11-25

    A study was made of the periodic steady state of the annual cycle solar energy system with seasonal heat storage at a practical operation. Cold heat in winter and warm heat in summer are stored in the seasonal storage tank, and these are each used in shift until when demand for cold/warm heat appears. Moreover, gap in quantity of cold/warm heat going in/out of the heat storage tank during a year is filled by natural energy such as solar energy, so that the system can be operated in annual cycles. Studies were conducted of the periodic unsteady term and the problem on lowering of performance during the term such as the periodic unsteady term of water temperature inside the seasonal heat storage tank and temperature of the soil around the storage tank, and the level of lowering of performance during the term, necessity of additional operation/control at the start of operation and aged deterioration of the system. Within the assumption, even if starting operation in any time of the year, the system could show the performance almost expected from the first operation year with no additional system operation and control required only at the start of operation. It is thought that the heat source selection control of heat pump largely contributes to this. 4 refs., 5 figs., 3 tabs.

  12. What's So Peculiar about the Cycle 23/24 Solar Minimum?

    Science.gov (United States)

    Sheeley, N. R., Jr.

    2010-06-01

    Traditionally, solar physicists become anxious around solar minimum, as they await the high-latitude sunspot groups of the new cycle. Now, we are in an extended sunspot minimum with conditions not seen in recent memory, and interest in the sunspot cycle has increased again. In this paper, I will describe some of the characteristics of the current solar minimum, including its great depth, its extended duration, its weak polar magnetic fields, and its small amount of open flux. Flux transport simulations suggest that these characteristics are a consequence of temporal variations of the Sun's large-scale meridional circulation.

  13. The Earth's Interaction With the Sun Over the Millennia From Analyses of Historical Sunspot, Auroral and Climate Records

    Science.gov (United States)

    Yau, K.

    2001-12-01

    A prolonged decrease in the Sun's irradiance during the Maunder Minimum has been proposed as a cause of the Little Ice Age ({ca} 1600-1800). Eddy [{Science} {192}, 1976, 1189] made this suggestion after noting that very few sunspots were observed from 1645 to 1715, indicative of a weakened Sun. Pre-telescopic Oriental sunspot records go back over 2200 years. Periods when no sunspots were seen have been documented by, {eg}, Clark [{Astron} {7}, 2/1979, 50]. Abundances of C 14 in tree rings and Be10 in ice cores are also good indicators of past solar activity. These isotopes are produced by cosmic rays high in the atmosphere. When the Sun is less active more of them are made and deposited at ground level. There is thus a strong {negative} correlation between their abundances and sunspot counts. Minima of solar activity in tree rings and a south polar ice core have been collated by, {eg}, Bard [{Earth Planet Sci Lett} {150} 1997, 453]; and show striking correspondence with periods when no sunspots were seen, centered at {ca} 900, 1050, 1500, 1700. Pang and Yau [{Eos} {79}, #45, 1998, F149] investigated the Medieval Minimum at 700, using in addition the frequency of auroral sighting7s, a good indicator of solar activity too [Yau, PhD thesis, 1988]; and found that the progression of minima in solar activity goes back to 700. Auroral frequency, C 14 and Be 10 concentrations are also affected by variations in the geomagnetic field. Deposition changes can also influence C 14 and Be 10 abundances. Sunspot counts are thus the only true indicator of solar activity. The Sun's bolometric variations (-0.3% for the Maunder Minimum) can contribute to climatic changes (\\0.5° C for the Little Ice Age)[{eg}, Lean, {GRL} {22}, 1995, 3195]. For times with no thermometer data, temperature can be estimated from, {eg}, Oxygen 18 isotopic abundance in ice cores, which in turn depends on the temperature of the ocean water it evaporated from. We have linked the Medieval Minimum to the cold

  14. Geographically selective assortment of cycles in pandemics: meta-analysis of data collected by Chizhevsky.

    Science.gov (United States)

    Gumarova, L; Cornélissen, G; Hillman, D; Halberg, F

    2013-10-01

    In the incidence patterns of cholera, diphtheria and croup during the past when they were of epidemic proportions, we document a set of cycles (periods), one of which was reported and discussed by A. L. Chizhevsky in the same data with emphasis on the mirroring in human disease of the ~11-year sunspot cycle. The data in this study are based on Chizhevsky’s book The Terrestrial Echo of Solar Storms and on records from the World Health Organization. For meta-analysis, we used the extended linear and nonlinear cosinor. We found a geographically selective assortment of various cycles characterizing the epidemiology of infections, which is the documented novel topic of this paper, complementing the earlier finding in the 21st century or shortly before, of a geographically selective assortment of cycles characterizing human sudden cardiac death. Solar effects, if any, interact with geophysical processes in contributing to this assortment.

  15. Solar wind and coronal structure near sunspot minimum - Pioneer and SMM observations from 1985-1987

    Science.gov (United States)

    Mihalov, J. D.; Barnes, A.; Hundhausen, A. J.; Smith, E. J.

    1990-01-01

    Changes in solar wind speed and magnetic polarity observed at the Pioneer spacecraft are discussed here in terms of the changing magnetic geometry implied by SMM coronagraph observations over the period 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations during this epoch show a systematic variation in coronal structure and the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet, and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum.

  16. Long periods (1 -10 mHz) geomagnetic pulsations variation with solar cycle in South Atlantic Magnetic Anomaly

    Science.gov (United States)

    Rigon Silva, Willian; Schuch, Nelson Jorge; Guimarães Dutra, Severino Luiz; Babulal Trivedi, Nalin; Claudir da Silva, Andirlei; Souza Savian, Fernando; Ronan Coelho Stekel, Tardelli; de Siqueira, Josemar; Espindola Antunes, Cassio

    The occurrence and intensity of the geomagnetic pulsations Pc-5 (2-7 mHz) and its relationship with the solar cycle in the South Atlantic Magnetic Anomaly -SAMA is presented. The study of geomagnetic pulsations is important to help the understanding of the physical processes that occurs in the magnetosphere region and help to predict geomagnetic storms. The fluxgate mag-netometers H, D and Z, three axis geomagnetic field data from the Southern Space Observatory -SSO/CRS/INPE -MCT, São Martinho da Serra (29.42° S, 53.87° W, 480m a.s.l.), RS, Brasil, a were analyzed and correlated with the solar wind parameters (speed, density and temperature) from the ACE and SOHO satellites. A digital filtering to enhance the 2-7 mHz geomagnetic pulsations was used. Five quiet days and five perturbed days in the solar minimum and in the solar maximum were selected for this analysis. The days were chosen based on the IAGA definition and on the Bartels Musical Diagrams (Kp index) for 2001 (solar maximum) and 2008 (solar minimum). The biggest Pc-5 amplitude averages differences between the H-component is 78,35 nT for the perturbed days and 1,60nT for the quiet days during the solar maximum. For perturbed days the average amplitude during the solar minimum is 8,32 nT, confirming a direct solar cycle influence in the geomagnetic pulsations intensity for long periods.

  17. Surge-like Oscillations above Sunspot Light Bridges Driven by Magnetoacoustic Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingwen; Tian, Hui; He, Jiansen; Wang, Linghua, E-mail: huitian@pku.edu.cn [School of Earth and Space Sciences, Peking University, 100871 Beijing (China)

    2017-03-20

    High-resolution observations of the solar chromosphere and transition region often reveal surge-like oscillatory activities above sunspot light bridges (LBs). These oscillations are often interpreted as intermittent plasma jets produced by quasi-periodic magnetic reconnection. We have analyzed the oscillations above an LB in a sunspot using data taken by the Interface Region Imaging Spectrograph . The chromospheric 2796 Å images show surge-like activities above the entire LB at any time, forming an oscillating wall. Within the wall we often see that the core of the Mg ii k 2796.35 Å line first experiences a large blueshift, and then gradually decreases to zero shift before increasing to a redshift of comparable magnitude. Such a behavior suggests that the oscillations are highly nonlinear and likely related to shocks. In the 1400 Å passband, which samples emission mainly from the Si iv ion, the most prominent feature is a bright oscillatory front ahead of the surges. We find a positive correlation between the acceleration and maximum velocity of the moving front, which is consistent with numerical simulations of upward propagating slow-mode shock waves. The Si iv 1402.77 Å line profile is generally enhanced and broadened in the bright front, which might be caused by turbulence generated through compression or by the shocks. These results, together with the fact that the oscillation period stays almost unchanged over a long duration, lead us to propose that the surge-like oscillations above LBs are caused by shocked p-mode waves leaked from the underlying photosphere.

  18. Watershed-scale changes in terrestrial nitrogen cycling during a period of decreased atmospheric nitrate and sulfur deposition

    Science.gov (United States)

    Sabo, Robert D.; Scanga, Sara E.; Lawrence, Gregory B.; Nelson, David M.; Eshleman, Keith N.; Zabala, Gabriel A.; Alinea, Alexandria A.; Schirmer, Charles D.

    2016-01-01

    Recent reports suggest that decreases in atmospheric nitrogen (N) deposition throughout Europe and North America may have resulted in declining nitrate export in surface waters in recent decades, yet it is unknown if and how terrestrial N cycling was affected. During a period of decreased atmospheric N deposition, we assessed changes in forest N cycling by evaluating trends in tree-ring δ15N values (between 1980 and 2010; n = 20 trees per watershed), stream nitrate yields (between 2000 and 2011), and retention of atmospherically-deposited N (between 2000 and 2011) in the North and South Tributaries (North and South, respectively) of Buck Creek in the Adirondack Mountains, USA. We hypothesized that tree-ring δ15N values would decline following decreases in atmospheric N deposition (after approximately 1995), and that trends in stream nitrate export and retention of atmospherically deposited N would mirror changes in tree-ring δ15N values. Three of the six sampled tree species and the majority of individual trees showed declining linear trends in δ15N for the period 1980–2010; only two individual trees showed increasing trends in δ15N values. From 1980 to 2010, trees in the watersheds of both tributaries displayed long-term declines in tree-ring δ15N values at the watershed scale (R = −0.35 and p = 0.001 in the North and R = −0.37 and p <0.001 in the South). The decreasing δ15N trend in the North was associated with declining stream nitrate concentrations (−0.009 mg N L−1 yr−1, p = 0.02), but no change in the retention of atmospherically deposited N was observed. In contrast, nitrate yields in the South did not exhibit a trend, and the watershed became less retentive of atmospherically deposited N (−7.3% yr−1, p < 0.001). Our δ15N results indicate a change in terrestrial N availability in both watersheds prior to decreases in atmospheric N deposition, suggesting that decreased atmospheric N deposition was not the sole driver of

  19. A new analytical approach for limit cycles and quasi-periodic solutions of nonlinear oscillators: the example of the forced Van der Pol Duffing oscillator

    International Nuclear Information System (INIS)

    Shukla, Anant Kant; Ramamohan, T R; Srinivas, S

    2014-01-01

    In this paper we propose a technique to obtain limit cycles and quasi-periodic solutions of forced nonlinear oscillators. We apply this technique to the forced Van der Pol oscillator and the forced Van der Pol Duffing oscillator and obtain for the first time their limit cycles (periodic) and quasi-periodic solutions analytically. We introduce a modification of the homotopy analysis method to obtain these solutions. We minimize the square residual error to obtain accurate approximations to these solutions. The obtained analytical solutions are convergent and agree well with numerical solutions even at large times. Time trajectories of the solution, its first derivative and phase plots are presented to confirm the validity of the proposed approach. We also provide rough criteria for the determination of parameter regimes which lead to limit cycle or quasi-periodic behaviour. (papers)

  20. Distribution of electric currents in sunspots from photosphere to corona

    Energy Technology Data Exchange (ETDEWEB)

    Gosain, Sanjay [National Solar Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Démoulin, Pascal [Observatoire de Paris, LESIA, UMR 8109 (CNRS), F-92195 Meudon Principal Cedex (France); López Fuentes, Marcelo [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC. 67, Suc. 28 Buenos Aires 1428 (Argentina)

    2014-09-20

    We present a study of two regular sunspots that exhibit nearly uniform twist from the photosphere to the corona. We derive the twist parameter in the corona and in the chromosphere by minimizing the difference between the extrapolated linear force-free field model field lines and the observed intensity structures in the extreme-ultraviolet images of the Sun. The chromospheric structures appear more twisted than the coronal structures by a factor of two. Further, we derive the vertical component of electric current density, j{sub z} , using vector magnetograms from the Hinode Solar Optical Telescope (SOT). The spatial distribution of j{sub z} has a zebra pattern of strong positive and negative values owing to the penumbral fibril structure resolved by Hinode/SOT. This zebra pattern is due to the derivative of the horizontal magnetic field across the thin fibrils; therefore, it is strong and masks weaker currents that might be present, for example, as a result of the twist of the sunspot. We decompose j{sub z} into the contribution due to the derivatives along and across the direction of the horizontal field, which follows the fibril orientation closely. The map of the tangential component has more distributed currents that are coherent with the chromospheric and coronal twisted structures. Moreover, it allows us to map and identify the direct and return currents in the sunspots. Finally, this decomposition of j{sub z} is general and can be applied to any vector magnetogram in order to better identify the weaker large-scale currents that are associated with coronal twisted/sheared structures.

  1. High Velocity Horizontal Motions at the Edge of Sunspot Penumbrae

    Science.gov (United States)

    Hagenaar-Daggett, Hermance J.; Shine, R.

    2010-05-01

    The outer edges of sunspot penumbrae have long been noted as a region of interesting dynamics including formation of MMFs, extensions and retractions of the penumbral tips, fast moving (2-3 km/s) bright features dubbed"streakers", and localized regions of high speed downflows interpreted as Evershed "sinks". Using 30s cadence movies of high spatial resolution G band and Ca II H images taken by the Hinode SOT/FPP instrument from 5-7 Jan 2007, we have been investigating the penumbra around a sunspot in AR 10933. In addition to the expected phenomena, we also see occasional small dark crescent-shaped features with high horizontal velocities (6.5 km/s) in G band movies. These appear to be emitted from penumbral tips. They travel about 1.5 Mm developing a bright wake that evolves into a slower moving (1-2 km/s) bright feature. In some cases, there may be an earlier outward propagating disturbance within the penumbra. We have also analyzed available Fe 6302 Stokes V images to obtain information on the magnetic field. Although only lower resolution 6302 images made with a slower cadence are available for these particular data sets, we can establish that the features have the opposite magnetic polarity of the sunspot. This observation may be in agreement with simulations showing that a horizontal flux tube develops crests that move outward with a velocity as large as 10 km/s. This work was supported by NASA contract NNM07AA01C.

  2. Observations of the birth and fine structure of sunspot penumbrae

    International Nuclear Information System (INIS)

    Collados, M.; Garcia de la Rosa, J.I.; Moreno-Insertis, F.; Vazquez, M.

    1985-01-01

    High resolution white-light pictures of sunspot penumbrae are presented. These include pictures showing details of their filamentary structure and some instances of birth of a penumbra. The observations are discussed in the framework of current penumbra theories. A series of pictures have been presented, which give additional evidence of the existence of dark penumbral filaments as individual structures. With respect to the birth of the penumbra some new observational aspects can be seen. The existence of the filamentary penumbra even in the first moments, its non uniformity and its short length are the major aspects derived from the pictures

  3. The visibility function and its effect on the observed characteristics of sunspot groups. 1

    International Nuclear Information System (INIS)

    Kopecky, M.; Kuklin, G.V.; Starkova, I.P.

    1985-01-01

    The paper is an introductory study to a series dealing with the visibility function, the function of foreshortening of sunspot group areas, and with the effect of these functions on the results of the statistical processing of observations, which has to be taken into account in interpreting the results. A ''diagram of observational conditions'' is described, which enables a number of statistical problems of sunspot groups on the rotating Sun to be solved by computer modelling or by graphical methods. Examples are given of the use of this diagram in studying the distribution of the observed lifetime of sunspot groups with a given actual lifetime, of the decrease in the number of sunspot groups towards the limb of the solar disc, of the east-west asymmetry of sunspot group appearance and disappearance. (author)

  4. Predictions of Solar Cycle 24: How are We Doing?

    Science.gov (United States)

    Pesnell, William D.

    2016-01-01

    Predictions of solar activity are an essential part of our Space Weather forecast capability. Users are requiring usable predictions of an upcoming solar cycle to be delivered several years before solar minimum. A set of predictions of the amplitude of Solar Cycle 24 accumulated in 2008 ranged from zero to unprecedented levels of solar activity. The predictions formed an almost normal distribution, centered on the average amplitude of all preceding solar cycles. The average of the current compilation of 105 predictions of the annual-average sunspot number is 106 +/- 31, slightly lower than earlier compilations but still with a wide distribution. Solar Cycle 24 is on track to have a below-average amplitude, peaking at an annual sunspot number of about 80. Our need for solar activity predictions and our desire for those predictions to be made ever earlier in the preceding solar cycle will be discussed. Solar Cycle 24 has been a below-average sunspot cycle. There were peaks in the daily and monthly averaged sunspot number in the Northern Hemisphere in 2011 and in the Southern Hemisphere in 2014. With the rapid increase in solar data and capability of numerical models of the solar convection zone we are developing the ability to forecast the level of the next sunspot cycle. But predictions based only on the statistics of the sunspot number are not adequate for predicting the next solar maximum. I will describe how we did in predicting the amplitude of Solar Cycle 24 and describe how solar polar field predictions could be made more accurate in the future.

  5. Oscillations in sunspot umbras due to trapped Alfven waves excited by overstability

    International Nuclear Information System (INIS)

    Uchida, Yutaka; Sakurai, Takashi.

    1975-01-01

    Oscillations observed in sunspot umbras are interpreted as a vertical motion in the atmosphere induced by a standing Alfven wave trapped in the region between the overstable layer under the photosphere and the chromosphere-corona transition layer. The Alfven wave motion is considered to be excited by the overstable convection occurring at the bottom of the abovementioned oscillating layer, and waves with special frequencies are selected as eigen-mode waves standing in the ''cavity,'' while other waves which are out of phase with themselves after reflections will disappear. It is shown by solving the eigen-value problem that the fundamental eigen frequency falls in a range around 0.04 rad s -1 (corresponding to 140-180 s) for the condition in the umbra of a typical spot, and also that the eigen frequencies do not depend greatly on the circumstantial physical or geometric parameters of the model atmosphere, such as the temperature in the layer, or the height of the transition layer, etc. The eigen frequencies, however, depend on the Alfven velocity at the base of the oscillating layer (or at the top of the overstable layer), but the latter quantity, which represents the stiffness of the magnetic tube of force against the overturning motion, takes roughly a common value for different sunspots according to SAVAGE's (1969) stability analysis of the umbral atmosphere against thermal convection, and thus gives a comparatively narrow range of resonant frequencies. In addition to the selection mechanism for oscillations of 140-180-s period, some other aspects of the oscillation, such as the relation to the running penumbral waves, are discussed. (auth.)

  6. Ten cycles of solar and geomagnetic activity

    International Nuclear Information System (INIS)

    Legrand, J.P.

    1981-01-01

    Series of 110 years of sunspot numbers and indices of geomagnetic activity are used with 17 years of solar wind data in order to study through solar cycles both stream and shock event solar activity. According to their patterns on Bartels diagrams of geomagnetic indices, stable wind streams and transient solar activities are separated from each other. Two classes of stable streams are identified: equatorial streams occurring sporadically, for several months, during the main phase of sunspot cycles and both polar streams established, for several years, at each cycle, before sunspot minimum. Polar streams are the first activity of solar cycles. For study of the relationship between transient geomagnetic phenomena and sunspot activity, we raise the importance of the contribution, at high spot number, of severe storms and, at low spot number, of short lived and unstable streams. Solar wind data are used to check and complete the above results. As a conclusion, we suggest a unified scheme of solar activity evolution with a starting point every eleventh year, a total duration of 17 years and an overlapping of 6 years between the first and the last phase of both successive series of phenomena: first, from polar field reversal to sunspot minimum, a phase of polar wind activity of the beginning cycle is superimposed on the weak contribution of shock events of the ending cycle; secondly, an equatorial phase mostly of shock events is superimposed on a variable contribution of short lived and sporadic stable equatorial stream activities; and thirdly a phase of low latitude shock events is superimposed on the polar stream interval of the following cycle. (orig.)

  7. SUNSPOT AND STARSPOT LIFETIMES IN A TURBULENT EROSION MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, Yuri E. [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand); Wheatland, M. S. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

    2017-01-10

    Quantitative models of sunspot and starspot decay predict the timescale of magnetic diffusion and may yield important constraints in stellar dynamo models. Motivated by recent measurements of starspot lifetimes, we investigate the disintegration of a magnetic flux tube by nonlinear diffusion. Previous theoretical studies are extended by considering two physically motivated functional forms for the nonlinear diffusion coefficient D : an inverse power-law dependence D ∝ B {sup −ν} and a step-function dependence of D on the magnetic field magnitude B . Analytical self-similar solutions are presented for the power-law case, including solutions exhibiting “super fast” diffusion. For the step-function case, the heat-balance integral method yields approximate solutions, valid for moderately suppressed diffusion in the spot. The accuracy of the resulting solutions is confirmed numerically, using a method which provides an accurate description of long-time evolution by imposing boundary conditions at infinite distance from the spot. The new models may allow insight into the differences and similarities between sunspots and starspots.

  8. Response of Solar Irradiance to Sunspot-area Variations

    Science.gov (United States)

    Dudok de Wit, T.; Kopp, G.; Shapiro, A.; Witzke, V.; Kretzschmar, M.

    2018-02-01

    One of the important open questions in solar irradiance studies is whether long-term variability (i.e., on timescales of years and beyond) can be reconstructed by means of models that describe short-term variability (i.e., days) using solar proxies as inputs. Preminger & Walton showed that the relationship between spectral solar irradiance and proxies of magnetic-flux emergence, such as the daily sunspot area, can be described in the framework of linear system theory by means of the impulse response. We significantly refine that empirical model by removing spurious solar-rotational effects and by including an additional term that captures long-term variations. Our results show that long-term variability cannot be reconstructed from the short-term response of the spectral irradiance, which questions the extension of solar proxy models to these timescales. In addition, we find that the solar response is nonlinear in a way that cannot be corrected simply by applying a rescaling to a sunspot area.

  9. Depressed emission between magnetic arcades near a sunspot

    Science.gov (United States)

    Ryabov, B. I.; Shibasaki, K.

    The locations of the depressed emission in microwaves, EUV and soft X-rays are compared with each other and with the location of the plasma outflow in the active region (AR) 8535 on the Sun. We found that two open-field regions overlap the regions of depressed emission near the AR's sunspot. These two open-field regions are simulated with the potential-field source-surface (PFSS) model under radial distances of RSS = 1.8 R⊙ and RSS = 2.5 R⊙. Each open-field region is located between the arcades of the loops of the same magnetic polarity. The former open-field region covers the region of the plasma outflow, which is thus useful for the tests on connection to the heliosphere. The utmost microwave depression of the intensity in the ordinary mode (the Very Large Array 15 GHz observations) also overlaps the region of the plasma outflow and thus indicates this outflow. The lasting for eight days depression in soft X-rays and the SOHO EIT 2.84× 10-8 m images are attributed to the evacuation of as hot coronal plasma as T≥ 2× 106 K from the extended in height (``open") magnetic structures. We conclude that the AR 8535 presents the sunspot atmosphere affected by the large-scale magnetic fields.

  10. Effect of harvest period on foliage production and dry matter distribution in five cassava cultivars during the second plant cycle

    Directory of Open Access Journals (Sweden)

    Edvaldo Sagrilo

    2006-11-01

    Full Text Available The objective of this work was to study the leaf production pattern and dry matter distribution in cassava during the second plant cycle. The completely randomized experimental design with four replications was used, with five cultivars in the main plots and ten harvest times in the sub-plots. Foliage production was affected by plant age, being higher in hot periods. Leaf blades and petioles dry matter content presented a linear increase due to a progressive decrease in the amount of young leaves and ontogenetic factors. The stems provided, temporarily, carbohydrates to the plant re-growth, delaying the availability and use of storage roots dry matter. The dry matter content in the storage roots was lower during the vegetative and higher during rest period. The storage roots diameter increased considerably when the amount of leaves was higher, indicating the importance of leaf area in the cassava plant production.O experimento foi conduzido de outubro de 1997 a maio de 1999, no Noroeste do Paraná, Brasil, com o objetivo de avaliar o padrão de produção de folhas e distribuição de massa seca em 5 cultivares de mandioca, durante o segundo ciclo vegetativo. Utilizou-se o delineamento experimental em blocos casualizados, com 4 repetições, no esquema de parcelas subdivididas, estando as cultivares nas parcelas e as épocas de colheita nas subparcelas. A produção de folhas foi afetada pela idade das plantas, sendo maior nos períodos de temperatura elevada. Os teores de massa seca nos limbos foliares e pecíolos aumentaram linearmente com a idade das plantas, devido à menor proporção de folhas jovens e a fatores ontogênicos inerentes à planta. As hastes proporcionaram, temporariamente, os assimilados necessários para a reestruturação vegetativa das plantas, protelando a disponibilidade e uso dos carboidratos armazenados nas raízes. O teor de massa seca nas raízes foi menor durante o período de crescimento vegetativo e maior

  11. POLAR NETWORK INDEX AS A MAGNETIC PROXY FOR THE SOLAR CYCLE STUDIES

    International Nuclear Information System (INIS)

    Priyal, Muthu; Banerjee, Dipankar; Ravindra, B.; Singh, Jagdev; Karak, Bidya Binay; Muñoz-Jaramillo, Andrés; Choudhuri, Arnab Rai

    2014-01-01

    The Sun has a polar magnetic field which oscillates with the 11 yr sunspot cycle. This polar magnetic field is an important component of the dynamo process which operates in the solar convection zone and produces the sunspot cycle. We have direct systematic measurements of the Sun's polar magnetic field only from about the mid-1970s. There are, however, indirect proxies which give us information about this field at earlier times. The Ca-K spectroheliograms taken at the Kodaikanal Solar Observatory during 1904-2007 have now been digitized with 4k × 4k CCD and have higher resolution (∼0.86 arcsec) than the other available historical data sets. From these Ca-K spectroheliograms, we have developed a completely new proxy (polar network index, hereafter PNI) for the Sun's polar magnetic field. We calculate PNI from the digitized images using an automated algorithm and calibrate our measured PNI against the polar field as measured by the Wilcox Solar Observatory for the period 1976-1990. This calibration allows us to estimate the polar fields for the earlier period up to 1904. The dynamo calculations performed with this proxy as input data reproduce reasonably well the Sun's magnetic behavior for the past century

  12. POLAR NETWORK INDEX AS A MAGNETIC PROXY FOR THE SOLAR CYCLE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Priyal, Muthu; Banerjee, Dipankar; Ravindra, B.; Singh, Jagdev [Indian Institute of Astrophysics,Koramangala, Bengaluru 560034 (India); Karak, Bidya Binay [Nordita, KTH Royal Institute of Technology and Stockholm University (Sweden); Muñoz-Jaramillo, Andrés [Montana State University, Bozeman, MT 59717 (United States); Choudhuri, Arnab Rai, E-mail: mpriya@iiap.res.in, E-mail: dipu@iiap.res.in [Indian Institute of Science, Bangalore (India)

    2014-09-20

    The Sun has a polar magnetic field which oscillates with the 11 yr sunspot cycle. This polar magnetic field is an important component of the dynamo process which operates in the solar convection zone and produces the sunspot cycle. We have direct systematic measurements of the Sun's polar magnetic field only from about the mid-1970s. There are, however, indirect proxies which give us information about this field at earlier times. The Ca-K spectroheliograms taken at the Kodaikanal Solar Observatory during 1904-2007 have now been digitized with 4k × 4k CCD and have higher resolution (∼0.86 arcsec) than the other available historical data sets. From these Ca-K spectroheliograms, we have developed a completely new proxy (polar network index, hereafter PNI) for the Sun's polar magnetic field. We calculate PNI from the digitized images using an automated algorithm and calibrate our measured PNI against the polar field as measured by the Wilcox Solar Observatory for the period 1976-1990. This calibration allows us to estimate the polar fields for the earlier period up to 1904. The dynamo calculations performed with this proxy as input data reproduce reasonably well the Sun's magnetic behavior for the past century.

  13. Complex network approach to characterize the statistical features of the sunspot series

    International Nuclear Information System (INIS)

    Zou, Yong; Liu, Zonghua; Small, Michael; Kurths, Jürgen

    2014-01-01

    Complex network approaches have been recently developed as an alternative framework to study the statistical features of time-series data. We perform a visibility-graph analysis on both the daily and monthly sunspot series. Based on the data, we propose two ways to construct the network: one is from the original observable measurements and the other is from a negative-inverse-transformed series. The degree distribution of the derived networks for the strong maxima has clear non-Gaussian properties, while the degree distribution for minima is bimodal. The long-term variation of the cycles is reflected by hubs in the network that span relatively large time intervals. Based on standard network structural measures, we propose to characterize the long-term correlations by waiting times between two subsequent events. The persistence range of the solar cycles has been identified over 15–1000 days by a power-law regime with scaling exponent γ = 2.04 of the occurrence time of two subsequent strong minima. In contrast, a persistent trend is not present in the maximal numbers, although maxima do have significant deviations from an exponential form. Our results suggest some new insights for evaluating existing models. (paper)

  14. Sunspots sketches during the solar eclipses of 9th January and 29th December of 1777 in Mexico

    Science.gov (United States)

    Domínguez-Castro, Fernando; Gallego, María Cruz; Vaquero, José Manuel

    2017-06-01

    Two sunspot observations recorded by the Mexican Felipe de Zúñiga y Ontiveros have been revealed from a manuscript. One sunspot group was recorded on 9th January 1777 and four sunspot groups on 29th December 1777. Both records were taken during the observation of solar eclipses from Mexico City and their description also included sketches of the solar disk with sunspots. The sunspot group corresponding to 9th January was also observed by Erasmus Lievog. The observation on 29th December 1777 is the only record corresponding to this date.

  15. MAGNETIC ROSSBY WAVES IN THE SOLAR TACHOCLINE AND RIEGER-TYPE PERIODICITIES

    International Nuclear Information System (INIS)

    Zaqarashvili, Teimuraz V.; Carbonell, Marc; Oliver, Ramon; Ballester, Jose Luis

    2010-01-01

    Apart from the eleven-year solar cycle, another periodicity around 155-160 days was discovered during solar cycle 21 in high-energy solar flares, and its presence in sunspot areas and strong magnetic flux has been also reported. This periodicity has an elusive and enigmatic character, since it usually appears only near the maxima of solar cycles, and seems to be related with a periodic emergence of strong magnetic flux at the solar surface. Therefore, it is probably connected with the tachocline, a thin layer located near the base of the solar convection zone, where a strong dynamo magnetic field is stored. We study the dynamics of Rossby waves in the tachocline in the presence of a toroidal magnetic field and latitudinal differential rotation. Our analysis shows that the magnetic Rossby waves are generally unstable and that the growth rates are sensitive to the magnetic field strength and to the latitudinal differential rotation parameters. Variation of the differential rotation and the magnetic field strength throughout the solar cycle enhance the growth rate of a particular harmonic in the upper part of the tachocline around the maximum of the solar cycle. This harmonic is symmetric with respect to the equator and has a period of 155-160 days. A rapid increase of the wave amplitude could give rise to a magnetic flux emergence leading to observed periodicities in solar activity indicators related to magnetic flux.

  16. Period and phase comparisons of near-decadal oscillations in solar, geomagnetic, and cosmic ray time series

    Science.gov (United States)

    Juckett, David A.

    2001-09-01

    A more complete understanding of the periodic dynamics of the Sun requires continued exploration of non-11-year oscillations in addition to the benchmark 11-year sunspot cycle. In this regard, several solar, geomagnetic, and cosmic ray time series were examined to identify common spectral components and their relative phase relationships. Several non-11-year oscillations were identified within the near-decadal range with periods of ~8, 10, 12, 15, 18, 22, and 29 years. To test whether these frequency components were simply low-level noise or were related to a common source, the phases were extracted for each component in each series. The phases were nearly identical across the solar and geomagnetic series, while the corresponding components in four cosmic ray surrogate series exhibited inverted phases, similar to the known phase relationship with the 11-year sunspot cycle. Cluster analysis revealed that this pattern was unlikely to occur by chance. It was concluded that many non-11-year oscillations truly exist in the solar dynamical environment and that these contribute to the complex variations observed in geomagnetic and cosmic ray time series. Using the different energy sensitivities of the four cosmic ray surrogate series, a preliminary indication of the relative intensities of the various solar-induced oscillations was observed. It provides evidence that many of the non-11-year oscillations result from weak interplanetary magnetic field/solar wind oscillations that originate from corresponding variations in the open-field regions of the Sun.

  17. Different periods of uranium and thorium occurrence in Madagascar (1960); Cycles uraniferes et thoriferes a Madagascar (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, M [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    In Madagascar, the first typical occurrences of thorium and uranium are about 500 million years old. Previously thorium and uranium were rather concentrated in the granitic and charnockitic zones, chiefly in minerals such as monazite, apatite and zircon. At the end of the Precambrian period, metasomatic granites occur especially in the anticlinal series (Andriba orthite granite). The granitization is followed by the formation of the main pegmatitic areas in the Island with Th-U niobotantalates, uraninite and beryl. The pegmatites are well developed in the synclinal series with a poor migmatization or no migmatization at all. In the same time a large uranium and thorium province with uranothorianite deposits appears within the calcomagnesian series of the Southern part of Madagascar. Later, large amounts of monazite were carried down to the detritic Karroo sediments during tile erosion of the metamorphic precambrian rocks. Monazite has been concentrated again by frequent marine incursions, till the present time. In the medium Karroo, near Folakara, uranium minerals occur in direct relation with carbonaceous material. Finally we must note the uranium occurrence in the pleistocene carbonaceous shales of Antsirabe basin, in contact with crystalline rocks. (author) [French] A Madagascar, le premier cycle uranifere et thorifere bien caracterise se situe aux alentours de 500 millions d'annees. Auparavant, le thorium et l'uranium sont concentres de preference dans les zones granitiques et charnockites sous forme de monazite, apatite ou zircon. Vers la fin du Precambrien, se produisent des granitisations metasomatiques, surtout dans les zones anticlinales (type Andriba a orthite). La fin de cette granitisation s'accompagne de la formation des principaux champs pegmatitiques de l'Ile a niobotantalates uraniferes, uraninite et beryl, qui se developpent de preference dans les series synclinales peu ou pas migmatisees. A cette meme epoque s'individualise au sein des series

  18. Geomagnetism during solar cycle 23: Characteristics

    Directory of Open Access Journals (Sweden)

    Jean-Louis Zerbo

    2013-05-01

    Full Text Available On the basis of more than 48 years of morphological analysis of yearly and monthly values of the sunspot number, the aa index, the solar wind speed and interplanetary magnetic field, we point out the particularities of geomagnetic activity during the period 1996–2009. We especially investigate the last cycle 23 and the long minimum which followed it. During this period, the lowest values of the yearly averaged IMF (3 nT and yearly averaged solar wind speed (364 km/s are recorded in 1996, and 2009 respectively. The year 2003 shows itself particular by recording the highest value of the averaged solar wind (568 km/s, associated to the highest value of the yearly averaged aa index (37 nT. We also find that observations during the year 2003 seem to be related to several coronal holes which are known to generate high-speed wind stream. From the long time (more than one century study of solar variability, the present period is similar to the beginning of twentieth century. We especially present the morphological features of solar cycle 23 which is followed by a deep solar minimum.

  19. On the chromospheric network structure around deVeloped groups of sunspots

    International Nuclear Information System (INIS)

    Kartashova, L.G.

    1980-01-01

    The chromospheric network structure around several developed groups of sunspots were studied on the basis of the observations in the Hsub(α) line. The resolution on the filtergrams was of 2. The following was found: 1) in the neighbourhood of the groups of sunspots 70% (from 870) of network cells stretch along fibrils direction (with accuracy 30 deg), and 15% of cells stretch approximately across that (at angles 70-90 deg); 2) out of the boundary of the main radial fibrils structure the groups of sunspots is often rounded by the system of network cells stretched approximately perpendicular to radial direction

  20. Solar magnetic field studies using the 12 micron emission lines. I - Quiet sun time series and sunspot slices

    Science.gov (United States)

    Deming, Drake; Boyle, Robert J.; Jennings, Donald E.; Wiedemann, Gunter

    1988-01-01

    The use of the extremely Zeeman-sensitive IR emission line Mg I, at 12.32 microns, to study solar magnetic fields. Time series observations of the line in the quiet sun were obtained in order to determine the response time of the line to the five-minute oscillations. Based upon the velocity amplitude and average period measured in the line, it is concluded that it is formed in the temperature minimum region. The magnetic structure of sunspots is investigated by stepping a small field of view in linear 'slices' through the spots. The region of penumbral line formation does not show the Evershed outflow common in photospheric lines. The line intensity is a factor of two greater in sunspot penumbrae than in the photosphere, and at the limb the penumbral emission begins to depart from optical thinness, the line source function increasing with height. For a spot near disk center, the radial decrease in absolute magnetic field strength is steeper than the generally accepted dependence.

  1. The photospheric vector magnetic field of a sunspot and its vertical gradient

    Science.gov (United States)

    Hagyard, M. J.; West, E. A.; Tandberg-Hanssen, E.; Smith, J. E.; Henze, W., Jr.; Beckers, J. M.; Bruner, E. C.; Hyder, C. L.; Gurman, J. B.; Shine, R. A.

    1981-01-01

    The results of direct comparisons of photospheric and transition region line-of-sight field observations of sunspots using the SMM UV spectrometer and polarimeter are reported. The analysis accompanying the data is concentrated on demonstrating that the sunspot concentrated magnetic field extends into the transition region. An observation of a sunspot on Oct. 23, 1980 at the S 18 E 03 location is used as an example. Maximum field strengths ranged from 2030-2240 gauss for large and small umbrae viewed and inclination of the field to the line-of-sight was determined for the photosphere and transition region. The distribution of the magnetic field over the sunspot and variation of the line-of-sight gradient are discussed, as are the magnitudes and gradients of the photospheric field across the penumbral-photospheric boundaries.

  2. The effect on cardiorespiratory fitness after an 8-week period of commuter cycling - A randomized controlled study in adults

    DEFF Research Database (Denmark)

    Møller, Niels Christian; Østergaard, Lars; Gade, Jens Raaberg

    2011-01-01

    OBJECTIVE: This study investigated the effect of commuter cycling on cardiorespiratory fitness in men and women. Secondary outcomes included body fat and blood pressure measurements. METHODS: In February 2009, 48 volunteers from the Island of Funen, Denmark were randomly assigned to either "no ch...

  3. SUNSPOT ROTATION AS A DRIVER OF MAJOR SOLAR ERUPTIONS IN THE NOAA ACTIVE REGION 12158

    Energy Technology Data Exchange (ETDEWEB)

    Vemareddy, P.; Ravindra, B. [Indian Institute of Astrophysics, Koramangala, Bangalore-560034 (India); Cheng, X., E-mail: vemareddy@iiap.res.in [School of Astronomy and Space Science, Nanjing University, Nanjing-210023 (China)

    2016-09-20

    We studied the development conditions of sigmoid structure under the influence of the magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from the Helioseismic Magnetic Imager and coronal EUV observations from the Atmospheric Imaging Assembly reveal that the erupting inverse-S sigmoid had roots at the location of the rotating sunspot. The sunspot rotates at a rate of 0°–5° h{sup −1} with increasing trend in the first half followed by a decrease. The time evolution of many non-potential parameters had a good correspondence with the sunspot rotation. The evolution of the AR magnetic structure is approximated by a time series of force-free equilibria. The non-linear force-free field magnetic structure around the sunspot manifests the observed sigmoid structure. Field lines from the sunspot periphery constitute the body of the sigmoid and those from the interior overlie the sigmoid, similar to a flux rope structure. While the sunspot was rotating, two major coronal mass ejection eruptions occurred in the AR. During the first (second) event, the coronal current concentrations were enhanced (degraded), consistent with the photospheric net vertical current; however, magnetic energy was released during both cases. The analysis results suggest that the magnetic connections of the sigmoid are driven by the slow motion of sunspot rotation, which transforms to a highly twisted flux rope structure in a dynamical scenario. Exceeding the critical twist in the flux rope probably leads to the loss of equilibrium, thus triggering the onset of the two eruptions.

  4. Levels of Arabidopsis thaliana leaf phosphatidic acids, phosphatidylserines, and most trienoate-containing polar lipid molecular species increase during the dark period of the diurnal cycle

    Directory of Open Access Journals (Sweden)

    Sara eMaatta

    2012-03-01

    Full Text Available Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark-light cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole mass spectrometry indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD is a family of enzymes that hydrolyzes phospholipids to produce phosphatidic acid. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of phosphatidic acid. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.

  5. INTERFERENCE OF THE RUNNING WAVES AT LIGHT BRIDGES OF A SUNSPOT

    Energy Technology Data Exchange (ETDEWEB)

    Su, J. T.; Priya, T. G.; Yu, S. J.; Zhang, M. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Ji, K. F. [Kunming University of Science and Technology, Kunming 650093 (China); Banerjee, D. [Indian Institute of Astrophysics, Koramangala Bangalore 560034 (India); Cao, W. D. [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Zhao, J. S.; Ji, H. S., E-mail: jt@bao.ac.cn [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

    2016-01-01

    The observations of chromospheric oscillations of two umbral light bridges (LBs) within a sunspot from NOAA Active Region 12127 are presented. It was found that the running umbral waves with periods of 2.2–2.6 minutes underwent very fast damping before approaching umbral boundaries, while those with higher periods (>2.6 minutes) could propagate outside umbrae. On two sides of each LB adjacent to umbrae, the cross-wavelet spectra displayed that the oscillations on them had a common significant power region with dominant frequencies of 2–6 minutes and phase differences of ∼90°. A counterstream of two running umbral waves in the 2–6 minute frequency range propagated toward the LBs, where they encountered each other and gave rise to constructive or even destructive interference on the LBs. In addition, the velocity and density perturbations on the LBs were found in opposite phases suggesting that the perturbations were caused by the downward propagating waves.

  6. Evolution of the Sunspot Number and Solar Wind B Time Series

    Science.gov (United States)

    Cliver, Edward W.; Herbst, Konstantin

    2018-03-01

    The past two decades have witnessed significant changes in our knowledge of long-term solar and solar wind activity. The sunspot number time series (1700-present) developed by Rudolf Wolf during the second half of the 19th century was revised and extended by the group sunspot number series (1610-1995) of Hoyt and Schatten during the 1990s. The group sunspot number is significantly lower than the Wolf series before ˜1885. An effort from 2011-2015 to understand and remove differences between these two series via a series of workshops had the unintended consequence of prompting several alternative constructions of the sunspot number. Thus it has been necessary to expand and extend the sunspot number reconciliation process. On the solar wind side, after a decade of controversy, an ISSI International Team used geomagnetic and sunspot data to obtain a high-confidence time series of the solar wind magnetic field strength (B) from 1750-present that can be compared with two independent long-term (> ˜600 year) series of annual B-values based on cosmogenic nuclides. In this paper, we trace the twists and turns leading to our current understanding of long-term solar and solar wind activity.

  7. A New Revision of the Solar Irradiance Climate Data Record Incorporates Recent Research into Proxies of Sunspot Darkening and the Sunspot Number Record

    Science.gov (United States)

    Coddington, O.; Lean, J.; Pilewskie, P.; Baranyi, T.; Snow, M. A.; Kopp, G.; Richard, E. C.; Lindholm, C.

    2017-12-01

    An operational climate data record (CDR) of total and spectral solar irradiance became available in November 2015 as part of the National Oceanographic and Atmospheric Administration's National Centers for Environmental Information Climate Data Record Program. The data record, which is updated quarterly, is available from 1610 to the present as yearly-average values and from 1882 to the present as monthly- and daily-averages, with associated time and wavelength-dependent uncertainties. It was developed jointly by the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics and the Naval Research Laboratory, and, together with the source code and supporting documentation, is available at https://www.ncdc.noaa.gov/cdr/. In the Solar Irradiance CDR, total solar irradiance (TSI) and solar spectral irradiance (SSI) are estimated from models that determine the changes from quiet Sun conditions arising from bright faculae and dark sunspots on the solar disk. The models are constructed using linear regression of proxies of solar sunspot and facular features with the approximately decade-long irradiance observations from the SOlar Radiation and Climate Experiment. A new revision of this data record was recently released in an ongoing effort to reduce solar irradiance uncertainties in two ways. First, the sunspot darkening proxy was revised using a new cross calibration of the current sunspot region observations made by the Solar Observing Optical Network with the historical records of the Royal Greenwich Observatory. This implementation affects modeled irradiances from 1882 - 1978. Second, the impact of a revised record of sunspot number by the Sunspot Index and Long-term Solar Observations center on modeled irradiances was assessed. This implementation provides two different reconstructions of historical, yearly-averaged irradiances from 1610-1881. Additionally, we show new, preliminary results that demonstrate improvements in modeled TSI by using

  8. Energy generation and the sulfur-carbon cycles: Final technical report for period March 1981 thru February 1985

    International Nuclear Information System (INIS)

    Zeikus, J.G.

    1987-05-01

    The aim of this research was to understand the role of anaerobic bacteria in natural and man-influenced carbon cycles in nature. The major goal was to elucidate how sulfur metabolism influenced organic decomposition in aquatic sediments. The research compared these processes in two different anaerobic ecosystems: the sulfate-depleted sediments of Lake Mendota, Wisconsin and the sulfate-saturated sediments of Great Salt Lake, Utah. The approach was both ecological and physiological, and employed both in situ characterization of carbon and sulfur metabolism with radiotracers and laboratory species isolation-characterization studies with pure and defined mixed cultures to demonstrate the prevalent environmental paths of carbon electrons, and sulfur during the anaerobic decomposition of organic matter. The significance of this research encompassed fundamental knowledge of the carbon sulfur cycles, applied knowledge on the microbial genesis of flammable gas and oil and extended knowledge on the diversity and metabolic activity of obligately anaerobic bacteria in nature. 13 refs

  9. Drought over Seoul and Its Association with Solar Cycles

    Directory of Open Access Journals (Sweden)

    Jong-Hyeok Park

    2013-12-01

    Full Text Available We have investigated drought periodicities occurred in Seoul to find out any indication of relationship between drought in Korea and solar activities. It is motivated, in view of solar-terrestrial connection, to search for an example of extreme weather condition controlled by solar activity. The periodicity of drought in Seoul has been re-examined using the wavelet transform technique as the consensus is not achieved yet. The reason we have chosen Seoul is because daily precipitation was recorded for longer than 200 years, which meets our requirement that analyses of drought frequency demand long-term historical data to ensure reliable estimates. We have examined three types of time series of the Effective Drought Index (EDI. We have directly analyzed EDI time series in the first place. And we have constructed and analyzed time series of histogram in which the number of days whose EDI is less than -1.5 for a given month of the year is given as a function of time, and one in which the number of occasions where EDI values of three consecutive days are all less than -1.5 is given as a function of time. All the time series data sets we analyzed are periodic. Apart from the annual cycle due to seasonal variations, periodicities shorter than the 11 year sunspot cycle, ~ 3, ~ 4, ~ 6 years, have been confirmed. Periodicities to which theses short periodicities (shorter than Hale period may be corresponding are not yet known. Longer periodicities possibly related to Gleissberg cycles, ~ 55, ~ 120 years, can be also seen. However, periodicity comparable to the 11 year solar cycle seems absent in both EDI and the constructed data sets.

  10. E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation.

    Science.gov (United States)

    Carcagno, Abel L; Marazita, Mariela C; Ogara, María F; Ceruti, Julieta M; Sonzogni, Silvina V; Scassa, María E; Giono, Luciana E; Cánepa, Eduardo T

    2011-01-01

    A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell cycle and provides an additional mechanism to limit E2F activity.

  11. E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation.

    Directory of Open Access Journals (Sweden)

    Abel L Carcagno

    Full Text Available BACKGROUND: A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. CONCLUSIONS/SIGNIFICANCE: The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell

  12. Transcriptome-wide analysis of the Trypanosoma cruzi proliferative cycle identifies the periodically expressed mRNAs and their multiple levels of control.

    Directory of Open Access Journals (Sweden)

    Santiago Chávez

    Full Text Available Trypanosoma cruzi is the protozoan parasite causing American trypanosomiasis or Chagas disease, a neglected parasitosis with important human health impact in Latin America. The efficacy of current therapy is limited, and its toxicity is high. Since parasite proliferation is a fundamental target for rational drug design, we sought to progress into its understanding by applying a genome-wide approach. Treating a TcI linage strain with hydroxyurea, we isolated epimastigotes in late G1, S and G2/M cell cycle stages at 70% purity. The sequencing of each phase identified 305 stage-specific transcripts (1.5-fold change, p≤0.01, coding for conserved cell cycle regulated proteins and numerous proteins whose cell cycle dependence has not been recognized before. Comparisons with the parasite T. brucei and the human host reveal important differences. The meta-analysis of T. cruzi transcriptomic and ribonomic data indicates that cell cycle regulated mRNAs are subject to sub-cellular compartmentalization. Compositional and structural biases of these genes- including CAI, GC content, UTR length, and polycistron position- may contribute to their regulation. To discover nucleotide motifs responsible for the co-regulation of cell cycle regulated genes, we looked for overrepresented motifs at their UTRs and found a variant of the cell cycle sequence motif at the 3' UTR of most of the S and G2 stage genes. We additionally identified hairpin structures at the 5' UTRs of a high proportion of the transcripts, suggesting that periodic gene expression might also rely on translation initiation in T. cruzi. In summary, we report a comprehensive list of T. cruzi cell cycle regulated genes, including many previously unstudied proteins, we show evidence favoring a multi-step control of their expression, and we identify mRNA motifs that may mediate their regulation. Our results provide novel information of the T. cruzi proliferative proteins and the integrated levels of

  13. The onset of the solar active cycle 22

    International Nuclear Information System (INIS)

    Ahluwalia, H.S.

    1989-01-01

    There is a great deal of interest in being able to predict the main characteristics of a solar activity cycle (SAC). One would like to know, for instance, how large the amplitude (R sub m) of a cycle is likely to be, i.e., the annual mean of the sunspot numbers at the maximum of SAC. Also, how long a cycle is likely to last, i.e., its period. It would also be interesting to be able to predict the details, like how steep the ascending phase of a cycle is likely to be. Questions like these are of practical importance to NASA in planning the launch schedule for the low altitude, expensive spacecrafts like the Hubble Space Telescope, the Space Station, etc. Also, one has to choose a proper orbit, so that once launched the threat of an atmospheric drag on the spacecraft is properly taken into account. Cosmic ray data seem to indicate that solar activity cycle 22 will surpass SAC 21 in activity. The value of R sub m for SAC 22 may approach that of SAC 19. It would be interesting to see whether this prediction is borne out. Researchers are greatly encouraged to proceed with the development of a comprehensive prediction model which includes information provided by cosmic ray data

  14. The onset of the solar active cycle 22

    Science.gov (United States)

    Ahluwalia, H. S.

    1989-01-01

    There is a great deal of interest in being able to predict the main characteristics of a solar activity cycle (SAC). One would like to know, for instance, how large the amplitude (R sub m) of a cycle is likely to be, i.e., the annual mean of the sunspot numbers at the maximum of SAC. Also, how long a cycle is likely to last, i.e., its period. It would also be interesting to be able to predict the details, like how steep the ascending phase of a cycle is likely to be. Questions like these are of practical importance to NASA in planning the launch schedule for the low altitude, expensive spacecrafts like the Hubble Space Telescope, the Space Station, etc. Also, one has to choose a proper orbit, so that once launched the threat of an atmospheric drag on the spacecraft is properly taken into account. Cosmic ray data seem to indicate that solar activity cycle 22 will surpass SAC 21 in activity. The value of R sub m for SAC 22 may approach that of SAC 19. It would be interesting to see whether this prediction is borne out. Researchers are greatly encouraged to proceed with the development of a comprehensive prediction model which includes information provided by cosmic ray data.

  15. Genomic divergence and lack of introgressive hybridization between two 13-year periodical cicadas support life cycle switching in the face of climate change.

    Science.gov (United States)

    Koyama, Takuya; Ito, Hiromu; Fujisawa, Tomochika; Ikeda, Hiroshi; Kakishima, Satoshi; Cooley, John R; Simon, Chris; Yoshimura, Jin; Sota, Teiji

    2016-11-01

    Life history evolution spurred by post-Pleistocene climatic change is hypothesized to be responsible for the present diversity in periodical cicadas (Magicicada), but the mechanism of life cycle change has been controversial. To understand the divergence process of 13-year and 17-year cicada life cycles, we studied genetic relationships between two synchronously emerging, parapatric 13-year periodical cicada species in the Decim group, Magicicada tredecim and M. neotredecim. The latter was hypothesized to be of hybrid origin or to have switched from a 17-year cycle via developmental plasticity. Phylogenetic analysis using restriction-site-associated DNA sequences for all Decim species and broods revealed that the 13-year M. tredecim lineage is genomically distinct from 17-year Magicicada septendecim but that 13-year M. neotredecim is not. We detected no significant introgression between M. tredecim and M. neotredecim/M. septendecim thus refuting the hypothesis that M. neotredecim are products of hybridization between M. tredecim and M. septendecim. Further, we found that introgressive hybridization is very rare or absent in the contact zone between the two 13-year species evidenced by segregation patterns in single nucleotide polymorphisms, mitochondrial lineage identity and head width and abdominal sternite colour phenotypes. Our study demonstrates that the two 13-year Decim species are of independent origin and nearly completely reproductively isolated. Combining our data with increasing observations of occasional life cycle change in part of a cohort (e.g. 4-year acceleration of emergence in 17-year species), we suggest a pivotal role for developmental plasticity in Magicicada life cycle evolution. © 2016 John Wiley & Sons Ltd.

  16. Principal components and iterative regression analysis of geophysical series: Application to Sunspot number (1750 2004)

    Science.gov (United States)

    Nordemann, D. J. R.; Rigozo, N. R.; de Souza Echer, M. P.; Echer, E.

    2008-11-01

    We present here an implementation of a least squares iterative regression method applied to the sine functions embedded in the principal components extracted from geophysical time series. This method seems to represent a useful improvement for the non-stationary time series periodicity quantitative analysis. The principal components determination followed by the least squares iterative regression method was implemented in an algorithm written in the Scilab (2006) language. The main result of the method is to obtain the set of sine functions embedded in the series analyzed in decreasing order of significance, from the most important ones, likely to represent the physical processes involved in the generation of the series, to the less important ones that represent noise components. Taking into account the need of a deeper knowledge of the Sun's past history and its implication to global climate change, the method was applied to the Sunspot Number series (1750-2004). With the threshold and parameter values used here, the application of the method leads to a total of 441 explicit sine functions, among which 65 were considered as being significant and were used for a reconstruction that gave a normalized mean squared error of 0.146.

  17. A steady-state supersonic downflow in the transition region above a sunspot umbra

    Science.gov (United States)

    Straus, Thomas; Fleck, Bernhard; Andretta, Vincenzo

    2015-10-01

    We investigate a small-scale (~1.5 Mm along the slit), supersonic downflow of about 90 km s-1 in the transition region above the lightbridged sunspot umbra in AR 11836. The observations were obtained with the Interface Region Spectrograph (IRIS) on 2013 September 2 from 16:40 to 17:59 UT. The downflow shows up as redshifted "satellite" lines of the Si iv and O iv transition region lines and is remarkably steady over the observing period of nearly 80 min. The downflow is not visible in the chromospheric lines, which only show an intensity enhancement at the location of the downflow. The density inferred from the line ratio of the redshifted satellites of the O iv lines (Ne = 1010.6 ± 0.25 cm-3) is only a factor 2 smaller than the one inferred from the main components (Ne = 1010.95 ± 0.20 cm-3). Consequently, this implies a substantial mass flux (~5 × 10-7 g cm-2 s-1), which would evacuate the overlying corona on timescales close to 10 s. We interpret these findings as evidence of a stationary termination shock of a supersonic siphon flow in a cool loop that is rooted in the central umbra of the spot. The movie is available in electronic form at http://www.aanda.org

  18. The topside ionosphere above Arecibo at equinox during sunspot maximum

    International Nuclear Information System (INIS)

    Bailey, G.J.

    1980-01-01

    The coupled time-dependent 0 + and H + continuity and momentum equations and 0 + , H + and electron heat balance equations are solved simultaneously within the L = 1.4 (Arecibo) magnetic flux tube between an altitude of 120 km and the equatorial plane. The results of the calculations are used in a study of the topside ionosphere above Arecibo at equinox during sunspot maximum. Magnetically quiet conditions are assumed. The results of the calculations show that the L = 1.4 magnetic flux tube becomes saturated from an arbitrary state within 2-3 days. During the day the ion content of the magnetic flux tube consists mainly of 0 + whereas 0 + and H + are both important during the night. There is an altitude region in the topside ionosphere during the day where ion-counterstreaming occurs with H + flowing downward and 0 + flowing upward. The conditions causing this ion-counterstreaming are discussed. There is a net chemical gain of H + at the higher altitudes. This H + diffuses both upwards and downwards whilst 0 + diffuses upwards from its solar e.u.v. production source which is most important at the lower altitudes. During the night the calculated 0 + and H + temperatures are very nearly equal whereas during the day there are occasions when the H + temperature exceeds the 0 - temperature by about 300 K. (author)

  19. Chromospheric Plasma Ejections in a Light Bridge of a Sunspot

    Science.gov (United States)

    Song, Donguk; Chae, Jongchul; Yurchyshyn, Vasyl; Lim, Eun-Kyung; Cho, Kyung-Suk; Yang, Heesu; Cho, Kyuhyoun; Kwak, Hannah

    2017-02-01

    It is well-known that light bridges (LBs) inside a sunspot produce small-scale plasma ejections and transient brightenings in the chromosphere, but the nature and origin of such phenomena are still unclear. Utilizing the high-spatial and high-temporal resolution spectral data taken with the Fast Imaging Solar Spectrograph and the TiO 7057 Å broadband filter images installed at the 1.6 m New Solar Telescope of Big Bear Solar Observatory, we report arcsecond-scale chromospheric plasma ejections (1.″7) inside a LB. Interestingly, the ejections are found to be a manifestation of upwardly propagating shock waves as evidenced by the sawtooth patterns seen in the temporal-spectral plots of the Ca II 8542 Å and Hα intensities. We also found a fine-scale photospheric pattern (1″) diverging with a speed of about 2 km s-1 two minutes before the plasma ejections, which seems to be a manifestation of magnetic flux emergence. As a response to the plasma ejections, the corona displayed small-scale transient brightenings. Based on our findings, we suggest that the shock waves can be excited by the local disturbance caused by magnetic reconnection between the emerging flux inside the LB and the adjacent umbral magnetic field. The disturbance generates slow-mode waves, which soon develop into shock waves, and manifest themselves as the arcsecond-scale plasma ejections. It also appears that the dissipation of mechanical energy in the shock waves can heat the local corona.

  20. ENHANCEMENT OF A SUNSPOT LIGHT WALL WITH EXTERNAL DISTURBANCES

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuhong; Zhang, Jun [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Erdélyi, Robert, E-mail: shuhongyang@nao.cas.cn [Solar Physics and Space Plasma Research Centre, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2016-12-20

    Based on the Interface Region Imaging Spectrograph observations, we study the response of a solar sunspot light wall to external disturbances. A flare occurrence near the light wall caused material to erupt from the lower solar atmosphere into the corona. Some material falls back to the solar surface and hits the light bridge (i.e., the base of the light wall), then sudden brightenings appear at the wall base followed by the rise of wall top, leading to an increase of the wall height. Once the brightness of the wall base fades, the height of the light wall begins to decrease. Five hours later, another nearby flare takes place, and a bright channel is formed that extends from the flare toward the light bridge. Although no obvious material flow along the bright channel is found, some ejected material is conjectured to reach the light bridge. Subsequently, the wall base brightens and the wall height begins to increase again. Once more, when the brightness of the wall base decays, the wall top fluctuates to lower heights. We suggest, based on the observed cases, that the interaction of falling material and ejected flare material with the light wall results in the brightenings of wall base and causes the height of the light wall to increase. Our results reveal that the light wall can be not only powered by the linkage of p -mode from below the photosphere, but may also be enhanced by external disturbances, such as falling material.

  1. Observations of Running Penumbral Waves Emerging in a Sunspot

    Science.gov (United States)

    Priya, T. G.; Wenda, Cao; Jiangtao, Su; Jie, Chen; Xinjie, Mao; Yuanyong, Deng; Robert, Erdélyi

    2018-01-01

    We present results from the investigation of 5 minute umbral oscillations in a single-polarity sunspot of active region NOAA 12132. The spectra of TiO, Hα, and 304 Å are used for corresponding atmospheric heights from the photosphere to lower corona. Power spectrum analysis at the formation height of Hα – 0.6 Å to the Hα center resulted in the detection of 5 minute oscillation signals in intensity interpreted as running waves outside the umbral center, mostly with vertical magnetic field inclination >15°. A phase-speed filter is used to extract the running wave signals with speed v ph > 4 km s‑1, from the time series of Hα – 0.4 Å images, and found twenty-four 3 minute umbral oscillatory events in a duration of one hour. Interestingly, the initial emergence of the 3 minute umbral oscillatory events are noticed closer to or at umbral boundaries. These 3 minute umbral oscillatory events are observed for the first time as propagating from a fraction of preceding running penumbral waves (RPWs). These fractional wavefronts rapidly separate from RPWs and move toward the umbral center, wherein they expand radially outwards suggesting the beginning of a new umbral oscillatory event. We found that most of these umbral oscillatory events develop further into RPWs. We speculate that the waveguides of running waves are twisted in spiral structures and hence the wavefronts are first seen at high latitudes of umbral boundaries and later at lower latitudes of the umbral center.

  2. On the Theory of Sunspots Proposed by Signor Kirchoff

    Directory of Open Access Journals (Sweden)

    Secchi A.

    2011-07-01

    Full Text Available Eileen Reeves (Department of Comparative Literature, Princeton University, Princeton, New Jersey, 08544 and Mary Posani (Department of French and Italian, The Ohio State University, Columbus, Ohio, 43221 provide a translation of Father Pietro Angelo Secchi’s classic work “ Secchi A. Sulla Teoria Delle Macchie Solari: Proposta dal sig. Kirchoff” as it appeared in Bullettino Meteorologico dell’ Osservatorio del Collegio Romano , 31 January 1864, v.3(4, 1–4. This was the first treatise to propose a partic- ulate photosphere floating on the gaseous body of the Sun. The idea would dominate astrophysical thought for the next 50 years. Secchi appears to have drafted the article, as a response to Gustav Kirchhoff’s proposal, echoing early Galilean ideas, that sunspots represented clouds which floated above the photosphere. Other than presenting a new solar model, noteworthy aspects of this work include Secchi’s appropriate insistence that materials do not emit the same light at the same temperature and his gentle rebuke of Kirchhoff relative to commenting on questions of astronomy.

  3. Development, characterization and evaluation of materials for open cycle MHD. Quarterly report for the period ending June 1978

    Energy Technology Data Exchange (ETDEWEB)

    Bates, J.L.; Marchant, D.D.; Daniel, J.L.

    1978-10-01

    The objectives of this program are directed toward the development and characterization of high temperature ceramics for open-cycle, coal-fired MHD power generators. The current activities are directed to electrode and insulator materials, and include (1) determination of the effects of alkali seed on the behavior of ceramics in a dc electric field; (2) development and testing of improved high temperature ceramic electrodes and insulators with controlled composition, microstructure, and properties; and (3) characterization and evaluation of materials utilized in channels being tested for MHD power generator development. Research is reported on (1) evaluation of metal electrodes from 250 hour MHD test, (2) characterization and properties of USSR MgO insulating wall material, (3) thermal diffusivity/thermal conductivity of electrode and insulator materials, (4) coprecipitation of ceramic powders, (5) properties of yttria chromites, and (6) rare earth hafnates. (WHK)

  4. M-number dependence of rotation period of the solar magnetic field and its effect on coronal hole and solar flare

    International Nuclear Information System (INIS)

    Saito, Takao; Oki, Tosio

    1989-01-01

    The photospheric magnetic field is revealed to rotate with different solar rotation periods depending on its m-number, or its longitudinal range. The m-dependent rotation reveals the unexplained solar cycle variation of the 28-day period of the IMF 2-sector structure in inclining/minimum years and of the 27-day period in the declining/minimum years. The m-dependent rotation reveals also the unexplained 155-day periodicity in the occurrence of solar flare clusters, suggesting a motion of the sunspot field relative to the large-scale field. The IMF sector structure is closely related to recurrent geomagnetic storms, while the flare occurrence is related to sporadic SC storms. Hence, the m-dependent rotation is quite important in the study of the STE forecast. (author)

  5. Nitrogen deposition may enhance soil carbon storage via change of soil respiration dynamic during a spring freeze-thaw cycle period.

    Science.gov (United States)

    Yan, Guoyong; Xing, Yajuan; Xu, Lijian; Wang, Jianyu; Meng, Wei; Wang, Qinggui; Yu, Jinghua; Zhang, Zhi; Wang, Zhidong; Jiang, Siling; Liu, Boqi; Han, Shijie

    2016-06-30

    As crucial terrestrial ecosystems, temperate forests play an important role in global soil carbon dioxide flux, and this process can be sensitive to atmospheric nitrogen deposition. It is often reported that the nitrogen addition induces a change in soil carbon dioxide emission in growing season. However, the important effects of interactions between nitrogen deposition and the freeze-thaw-cycle have never been investigated. Here we show nitrogen deposition delays spikes of soil respiration and weaken soil respiration. We found the nitrogen addition, time and nitrogen addition×time exerted the negative impact on the soil respiration of spring freeze-thaw periods due to delay of spikes and inhibition of soil respiration (p nitrogen), 39% (medium-nitrogen) and 36% (high-nitrogen) compared with the control. And the decrease values of soil respiration under medium- and high-nitrogen treatments during spring freeze-thaw-cycle period in temperate forest would be approximately equivalent to 1% of global annual C emissions. Therefore, we show interactions between nitrogen deposition and freeze-thaw-cycle in temperate forest ecosystems are important to predict global carbon emissions and sequestrations. We anticipate our finding to be a starting point for more sophisticated prediction of soil respirations in temperate forests ecosystems.

  6. Chromosomal radiosensitivity during the G2 cell-cycle period of skin fibroblasts from individuals with familial cancer

    International Nuclear Information System (INIS)

    Parshad, R.; Sanford, K.K.; Jones, G.M.

    1985-01-01

    The authors reported previously that human cells after neoplastic transformation in culture had acquired an increased susceptibility to chromatid damage induced by x-irradiation during the G2 phase of the cell cycle. Evidence suggested that this results from deficient DNA repair during G2 phase. Cells derived from human tumors also showed enhanced G2-phase chromosomal radiosensitivity. Furthermore, skin fibroblasts from individuals with genetic diseases predisposing to a high risk of cancer, including ataxia-telangiectasia, Bloom syndrome, Fanconi anemia, and xeroderma pigmentosum exhibited enhanced G2-phase chromosomal radiosensitivity. The present study shows that apparently normal skin fibroblasts from individuals with familial cancer--i.e., from families with a history of neoplastic disease--also exhibit enhanced G2-phase chromosomal radiosensitivity. This radiosensitivity appears, therefore, to be associated with both a genetic predisposition to cancer and a malignant neoplastic state. Furthermore, enhanced G2-phase chromosomal radiosensitivity may provide the basis for an assay to detect genetic susceptibility to cancer

  7. Sunspot activity and influenza pandemics: a statistical assessment of the purported association.

    Science.gov (United States)

    Towers, S

    2017-10-01

    Since 1978, a series of papers in the literature have claimed to find a significant association between sunspot activity and the timing of influenza pandemics. This paper examines these analyses, and attempts to recreate the three most recent statistical analyses by Ertel (1994), Tapping et al. (2001), and Yeung (2006), which all have purported to find a significant relationship between sunspot numbers and pandemic influenza. As will be discussed, each analysis had errors in the data. In addition, in each analysis arbitrary selections or assumptions were also made, and the authors did not assess the robustness of their analyses to changes in those arbitrary assumptions. Varying the arbitrary assumptions to other, equally valid, assumptions negates the claims of significance. Indeed, an arbitrary selection made in one of the analyses appears to have resulted in almost maximal apparent significance; changing it only slightly yields a null result. This analysis applies statistically rigorous methodology to examine the purported sunspot/pandemic link, using more statistically powerful un-binned analysis methods, rather than relying on arbitrarily binned data. The analyses are repeated using both the Wolf and Group sunspot numbers. In all cases, no statistically significant evidence of any association was found. However, while the focus in this particular analysis was on the purported relationship of influenza pandemics to sunspot activity, the faults found in the past analyses are common pitfalls; inattention to analysis reproducibility and robustness assessment are common problems in the sciences, that are unfortunately not noted often enough in review.

  8. The public health impact of economic fluctuations in a Latin American country: mortality and the business cycle in Colombia in the period 1980-2010.

    Science.gov (United States)

    Arroyave, Ivan; Hessel, Philipp; Burdorf, Alex; Rodriguez-Garcia, Jesus; Cardona, Doris; Avendaño, Mauricio

    2015-05-27

    Studies in high-income countries suggest that mortality is related to economic cycles, but few studies have examined how fluctuations in the economy influence mortality in low- and middle-income countries. We exploit regional variations in gross domestic product per capita (GDPpc) over the period 1980-2010 in Colombia to examine how changes in economic output relate to adult mortality. Data on the number of annual deaths at ages 20 years and older (n = 3,506,600) from mortality registries, disaggregated by age groups, sex and region, were linked to population counts for the period 1980-2010. We used region fixed effect models to examine whether changes in regional GDPpc were associated with changes in mortality. We carried out separate analyses for the periods 1980-1995 and 2000-2010 as well as by sex, distinguishing three age groups: 20-44 (predominantly young working adults), 45-64 (middle aged working adults), and 65+ (senior, predominantly retired individuals). The association between regional economic conditions and mortality varied by period and age groups. From 1980 to 1995, increases in GDPpc were unrelated to mortality at ages 20 to 64, but they were associated with reductions in mortality for senior men. In contrast, from 2000 to 2010, changes in GDPpc were not associated with old age mortality, while an increase in GDPpc was associated with a decline in mortality at ages 20-44 years. Analyses restricted to regions with high registration coverage yielded similar albeit less precise estimates for most sub-groups. The relationship between business cycles and mortality varied by period and age in Colombia. Most notably, mortality shifted from being acyclical to being countercyclical for males aged 20-44, while it shifted from being countercyclical to being acyclical for males aged 65+.

  9. Trends and Weekly Cycles in a Large Swiss Emergency Centre: A 10 Year Period at the University Hospital of Bern

    Directory of Open Access Journals (Sweden)

    Christian T. Braun

    2017-10-01

    Full Text Available Popular demand for high quality care has increased in recent years. This is also the case for medical services and support at all times of the day and night is nowadays required. During the last ten years, there has been a marked increase in the demands on hospital emergency hospitals, particularly in the Western industrialized countries. The present retrospective study investigates how the demands on a large Swiss university centre have changed over a period of 10 years. Patient numbers are differentiated by age, gender, nationality, weekday and mode of referral. A retrospective analysis was performed of the data of the patients admitted to the Emergency Centre of Bern University Medical Hospital (Inselspital during the ten-year period from 2004 up to and including 2013 and who were treated as emergencies. A total of 264,272 patients were included in the study. It was shown that there was an uninterrupted annual increase from 23,555 patients in 2004 to 34,918 patients in 2013 (+48%. Most patients came to the Emergency Centre on Mondays, followed by Fridays. Because of the marked increase in life expectancy and the resulting demographic changes, there has been a marked increase in the number of older patients coming to the Emergency Centre for acute medical care. It was found that there were disproportionately high numbers of patients aged 20 to 49 years who were not Swiss citizens. In contrast, most patients over 60 were Swiss. In the coming years, emergency centres will have to adapt to the continued increase in patient numbers. This trend will continue, so that it is essential to consider the sociodemographic structure of a region when planning the availability of emergency medical care.

  10. SOLAR CYCLE PROPAGATION, MEMORY, AND PREDICTION: INSIGHTS FROM A CENTURY OF MAGNETIC PROXIES

    International Nuclear Information System (INIS)

    Muñoz-Jaramillo, Andrés; DeLuca, Edward E.; Dasi-Espuig, María; Balmaceda, Laura A.

    2013-01-01

    The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. A major contributor to the disagreement is the lack of direct long-term databases covering different components of the solar magnetic field (toroidal versus poloidal). Here, we use sunspot area and polar faculae measurements spanning a full century (as our toroidal and poloidal field proxies) to study solar cycle propagation, memory, and prediction. Our results substantiate predictions based on the polar magnetic fields, whereas we find sunspot area to be uncorrelated with cycle amplitude unless multiplied by area-weighted average tilt. This suggests that the joint assimilation of tilt and sunspot area is a better choice (with aims to cycle prediction) than sunspot area alone, and adds to the evidence in favor of active region emergence and decay as the main mechanism of poloidal field generation (i.e., the Babcock-Leighton mechanism). Finally, by looking at the correlation between our poloidal and toroidal proxies across multiple cycles, we find solar cycle memory to be limited to only one cycle.

  11. Water vapour inter-comparison effort in the framework of the hydrological cycle in the mediterranean experiment - special observation period (hymex-sop1)

    Science.gov (United States)

    Summa, Donato; Di Girolamo, Paolo; Flamant, Cyrille; De Rosa, Benedetto; Cacciani, Marco; Stelitano, Dario

    2018-04-01

    Accurate measurements of the vertical profiles of water vapour are of paramount importance for most key areas of atmospheric sciences. A comprehensive inter-comparison between different remote sensing and in-situ sensors has been carried out in the frame work of the first Special Observing Period of the Hydrological cycle in the Mediterranean Experiment for the purpose of obtaining accurate error estimates for these sensors. The inter-comparison involves a ground-based Raman lidar (BASIL), an airborne DIAL (LEANDRE2), a microwave radiometer, radiosondes and aircraft in-situ sensors.

  12. Water vapour inter-comparison effort in the framework of the hydrological cycle in the mediterranean experiment – special observation period (hymex-sop1

    Directory of Open Access Journals (Sweden)

    Summa Donato

    2018-01-01

    Full Text Available Accurate measurements of the vertical profiles of water vapour are of paramount importance for most key areas of atmospheric sciences. A comprehensive inter-comparison between different remote sensing and in-situ sensors has been carried out in the frame work of the first Special Observing Period of the Hydrological cycle in the Mediterranean Experiment for the purpose of obtaining accurate error estimates for these sensors. The inter-comparison involves a ground-based Raman lidar (BASIL, an airborne DIAL (LEANDRE2, a microwave radiometer, radiosondes and aircraft in-situ sensors.

  13. [Specific features of the functional state of the cardiorespiratory system in athletes differing in the types of muscular activity during the preparatory period of the training cycle].

    Science.gov (United States)

    Ivanova, N B

    2011-01-01

    The present study of the functional state of the cadiorespiratory system included athletes engaged in cyclic team sports. The state of the cardiorespiratory system was estimated from the measurement of central hemodynamics and cardiac rhythm variability, results of electrocardiography, spirography, and pneumotachography performed during the preparatory period for the training cycle. It was shown that the cardiovascular and respiratory systems as well as vegetative regulation of the cardiac rhythm of the athletes under examination underwent differently directed structural modification depending on the specific patterns of muscular activity.

  14. Chromospheric Plasma Ejections in a Light Bridge of a Sunspot

    Energy Technology Data Exchange (ETDEWEB)

    Song, Donguk; Chae, Jongchul; Yang, Heesu; Cho, Kyuhyoun; Kwak, Hannah [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Yurchyshyn, Vasyl [Big Bear Solar Observatory, New Jersey Institute of Technology, 40386 North Shore Lane, Big Bear City, CA 92314-9672 (United States); Lim, Eun-Kyung; Cho, Kyung-Suk, E-mail: dusong@astro.snu.ac.kr [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of)

    2017-02-01

    It is well-known that light bridges (LBs) inside a sunspot produce small-scale plasma ejections and transient brightenings in the chromosphere, but the nature and origin of such phenomena are still unclear. Utilizing the high-spatial and high-temporal resolution spectral data taken with the Fast Imaging Solar Spectrograph and the TiO 7057 Å broadband filter images installed at the 1.6 m New Solar Telescope of Big Bear Solar Observatory, we report arcsecond-scale chromospheric plasma ejections (1.″7) inside a LB. Interestingly, the ejections are found to be a manifestation of upwardly propagating shock waves as evidenced by the sawtooth patterns seen in the temporal-spectral plots of the Ca ii 8542 Å and H α intensities. We also found a fine-scale photospheric pattern (1″) diverging with a speed of about 2 km s{sup −1} two minutes before the plasma ejections, which seems to be a manifestation of magnetic flux emergence. As a response to the plasma ejections, the corona displayed small-scale transient brightenings. Based on our findings, we suggest that the shock waves can be excited by the local disturbance caused by magnetic reconnection between the emerging flux inside the LB and the adjacent umbral magnetic field. The disturbance generates slow-mode waves, which soon develop into shock waves, and manifest themselves as the arcsecond-scale plasma ejections. It also appears that the dissipation of mechanical energy in the shock waves can heat the local corona.

  15. MEASUREMENTS OF THE ABSORPTION AND SCATTERING CROSS SECTIONS FOR THE INTERACTION OF SOLAR ACOUSTIC WAVES WITH SUNSPOTS

    International Nuclear Information System (INIS)

    Zhao, Hui; Chou, Dean-Yi

    2016-01-01

    The solar acoustic waves are modified by the interaction with sunspots. The interaction can be treated as a scattering problem: an incident wave propagating toward a sunspot is scattered by the sunspot into different modes. The absorption cross section and scattering cross section are two important parameters in the scattering problem. In this study, we use the wavefunction of the scattered wave, measured with a deconvolution method, to compute the absorption cross section σ ab and the scattering cross section σ sc for the radial order n = 0–5 for two sunspots, NOAA 11084 and NOAA 11092. In the computation of the cross sections, the random noise and dissipation in the measured acoustic power are corrected. For both σ ab and σ sc , the value of NOAA 11092 is greater than that of NOAA 11084, but their overall n dependence is similar: decreasing with n . The ratio of σ ab of NOAA 11092 to that of NOAA 11084 approximately equals the ratio of sunspot radii for all n , while the ratio of σ sc of the two sunspots is greater than the ratio of sunspot radii and increases with n . This suggests that σ ab is approximately proportional to the sunspot radius, while the dependence of σ sc on radius is faster than the linear increase.

  16. MEASUREMENTS OF THE ABSORPTION AND SCATTERING CROSS SECTIONS FOR THE INTERACTION OF SOLAR ACOUSTIC WAVES WITH SUNSPOTS

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hui [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 200012 (China); Chou, Dean-Yi, E-mail: chou@phys.nthu.edu.tw [Physics Department, National Tsing Hua University, Hsinchu, Taiwan (China)

    2016-05-01

    The solar acoustic waves are modified by the interaction with sunspots. The interaction can be treated as a scattering problem: an incident wave propagating toward a sunspot is scattered by the sunspot into different modes. The absorption cross section and scattering cross section are two important parameters in the scattering problem. In this study, we use the wavefunction of the scattered wave, measured with a deconvolution method, to compute the absorption cross section σ {sub ab} and the scattering cross section σ {sub sc} for the radial order n = 0–5 for two sunspots, NOAA 11084 and NOAA 11092. In the computation of the cross sections, the random noise and dissipation in the measured acoustic power are corrected. For both σ {sub ab} and σ {sub sc}, the value of NOAA 11092 is greater than that of NOAA 11084, but their overall n dependence is similar: decreasing with n . The ratio of σ {sub ab} of NOAA 11092 to that of NOAA 11084 approximately equals the ratio of sunspot radii for all n , while the ratio of σ {sub sc} of the two sunspots is greater than the ratio of sunspot radii and increases with n . This suggests that σ {sub ab} is approximately proportional to the sunspot radius, while the dependence of σ {sub sc} on radius is faster than the linear increase.

  17. Absorption of acoustic waves by sunspots. II - Resonance absorption in axisymmetric fibril models

    Science.gov (United States)

    Rosenthal, C. S.

    1992-01-01

    Analytical calculations of acoustic waves scattered by sunspots which concentrate on the absorption at the magnetohydrodynamic Alfven resonance are extended to the case of a flux-tube embedded in a uniform atmosphere. The model is based on a flux-tubes of varying radius that are highly structured, translationally invariant, and axisymmetric. The absorbed fractional energy is determined for different flux-densities and subphotospheric locations with attention given to the effects of twist. When the flux is highly concentrated into annuli efficient absorption is possible even when the mean magnetic flux density is low. The model demonstrates low absorption at low azimuthal orders even in the presence of twist which generally increases the range of wave numbers over which efficient absorption can occur. Resonance absorption is concluded to be an efficient mechanism in monolithic sunspots, fibril sunspots, and plage fields.

  18. On the determination of heliographic positions and rotation velocities of sunspots. Pt. 2

    International Nuclear Information System (INIS)

    Balthasar, H.

    1983-01-01

    Using sunspot positions of small sunspots observed at Debrecen and Locarno as well as positions of recurrent sunspots taken from the Greenwich Photoheliographic Results (1940-1976) the influence of the Wilson depression on the rotation velocities was investigated. It was found that the Wilson depression can be determined by minimizing errors of the rotation velocities or minimizing the differences of rotation velocities determined from disk passages and central meridian passages. The Wilson depressions found were between 765 km and 2500 km for the first sample while they were between 0 km and several 1000 km for the second sample. The averaged Wilson depression for the second sample is between 500 km and 965 km depending on the reduction method. A dependence of the Wilson depression on the age of the spots investigated seems not to exist. (orig.)

  19. Improvement of the training process of qualified female athletes engaged in bodybuilding in the general preparatory stage of the preparatory period, taking into account the biological cycle

    Directory of Open Access Journals (Sweden)

    Viacheslav Mulyk

    2017-06-01

    Full Text Available Purpose: substantiation of the methodology of the training process of qualified female athletes engaged in bodybuilding in the general preparatory stage of the preparatory period, taking into account the biological cycle. Material & Methods: in the study participated 18 qualified female athletes engaged in bodybuilding, included in the Kharkov region team of bodybuilding. Results: comparative characteristic of the most frequently used methodology of the training process in bodybuilding are shows. An optimal methodology for qualified female athletes engaged in bodybuilding has been developed and justified, depending on the initial form of the athlete at the beginning of the general preparatory stage of the training. The dependence of the change in the body weight of female athletes from the training process is shows. Conclusion: on the basis of the study, the author suggests an optimal training methodology depending on the mesocycle of training in the preparatory period in the general preparatory stage.

  20. The Solar Cycle and, How Do We Know What We Know?

    Science.gov (United States)

    Adams, Mitzi

    2013-01-01

    Through the use of observations, mathematics, mathematical tools (such as graphs), inference, testing, and prediction we have gathered evidence that there are sunspots, a solar cycle, and have begun to understand more about our star, the Sun. We are making progress in understanding the cause of the solar cycle. We expect solar cycle 24 to peak soon. Cycle 24 will be the smallest cycle in 100 years.

  1. 22 Year Periodicity in the Solar Differential Rotation

    Indian Academy of Sciences (India)

    tribpo

    1995). Recently, we determined periodicities in the solar differential rotation through the power spectrum analysis of the differential rotation parameters derived from the data on sunspot groups compiled from Greenwich Photoheliographic Results (GPR) during 1879 1976 and from Mt. Wilson velocity data during 1969 1994 ...

  2. Optimality of cycle time and inventory decisions in a two echelon inventory system with exponential price dependent demand under credit period

    Science.gov (United States)

    Krugon, Seelam; Nagaraju, Dega

    2017-05-01

    This work describes and proposes an two echelon inventory system under supply chain, where the manufacturer offers credit period to the retailer with exponential price dependent demand. The model is framed as demand is expressed as exponential function of retailer’s unit selling price. Mathematical model is framed to demonstrate the optimality of cycle time, retailer replenishment quantity, number of shipments, and total relevant cost of the supply chain. The major objective of the paper is to provide trade credit concept from the manufacturer to the retailer with exponential price dependent demand. The retailer would like to delay the payments of the manufacturer. At the first stage retailer and manufacturer expressions are expressed with the functions of ordering cost, carrying cost, transportation cost. In second stage combining of the manufacturer and retailer expressions are expressed. A MATLAB program is written to derive the optimality of cycle time, retailer replenishment quantity, number of shipments, and total relevant cost of the supply chain. From the optimality criteria derived managerial insights can be made. From the research findings, it is evident that the total cost of the supply chain is decreased with the increase in credit period under exponential price dependent demand. To analyse the influence of the model parameters, parametric analysis is also done by taking with help of numerical example.

  3. Possibility to explain the temperature distribution in sunspots by an anisotropic heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Eschrich, K O; Krause, F [Akademie der Wissenschaften der DDR, Potsdam. Zentralinstitut fuer Astrophysik

    1977-01-01

    Numerical solutions of a heat conduction problem in an anisotropic medium are used for a discussion of the possibility to explain the temperature distribution in sunspots and their environment. The anisotropy is assumed being due to the strong magnetic field in sunspots and the region below. This magnetic field forces the convection to take an anisotropic structure (two-dimensional turbulence) and thus the region gets anisotropic conduction properties, on the average. The discussion shows that the observed temperature profiles can be explained in the case the depth of the region of anisotropy is about as large as the diameter of the spot or larger.

  4. Outflow of chromospheric emission features from the rim of a sunspot

    Science.gov (United States)

    Liu, S.-Y.

    1973-01-01

    In viewing a 16 mm movie made from a time sequence of spectroheliograms, some of these emission features are found to move outward from the rim of the sunspot until they are eventually lost in the small plage. There are two interpretations for the streaming of the magnetic features. It is possible that kinks in the line of force propagate along a horizontal extension of the penumbral magnetic field. Alternatively, fragments of the sunspot magnetic field are carried away by the photospheric velocity field.

  5. Midterm Periodicity Analysis of the Mount Wilson Magnetic Indices Using the Synchrosqueezing Transform

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Song; Wang, Feng; Deng, Hui; Yang, Yunfei [Yunnan Key Laboratory of Computer Technology Application/Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650500 (China); Yu, Lan, E-mail: ynkmfs@escience.cn [Department of Mechanical and Electrical Engineering, Yunnan Land and Resources Vocational College, Kunming 650217 (China)

    2017-08-10

    A novel time–frequency technique, called the synchrosqueezing transform (SST), is used to investigate the midterm periodic variations of magnetic fields on the solar surface. The Magnetic Plage Strength Index (MPSI) and the Mount Wilson Sunspot Index (MWSI), measured daily by the Mount Wilson Observatory between 1970 January 19 and 2012 January 22, are selected. Short-, mid, and longer-term periodicities are represented and decomposed by the SST with hardly any mode mixing. This demonstrates that the SST is a useful time–frequency analysis technique to characterize the periodic modes of helioseismic data. Apart from the fundamental modes of the annual periodicity, ∼27 day rotational cycle and ∼11 year solar cycle, the SST reveals several midterm periodicities in the two magnetic activity indices, specifically, ∼157 days (i.e., Rieger-type periodicity), and ∼1.3 and 1.7 years. The periodic modes, with 116.4 and 276.2 day periodicity in the MPSI, 108.5 and 251.6 day periodicity in the MWSI, and 157.7 day periodicity in the two indices, are in better accord with those significant periodicities derived from the Rossby waves theoretical model. This study suggests that the modes are caused by Rossby waves. For the 1.30 and 1.71 year periodicity of the MPSI, and the 1.33 and 1.67 year periodicity of the MWSI, our analysis infers that they are related to those periodicities with the same timescale in the interior of the Sun and in the high atmospheric layers.

  6. Periodicities observed on solar flux index (F10.7) during geomagnetic disturbances

    Science.gov (United States)

    Adhikari, B.; Narayan, C.; Chhatkuli, D. N.

    2017-12-01

    Solar activities change within the period of 11 years. Sometimes the greatest event occurs in the period of solar maxima and the lowest activity occurs in the period of solar minimum. During the time period of solar activity sunspots number will vary. A 10.7 cm solar flux measurement is a determination of the strength of solar radio emission. The solar flux index is more often used for the prediction and monitoring of the solar activity. This study mainly focused on the variation on solar flux index and amount of electromagnetic wave in the atmosphere. Both seasonal and yearly variation on solar F10.7 index. We also analyzed the dataset obatained from riometer.Both instruments show seasonal and yearly variations. We also observed the solar cycle dependence on solar flux index and found a strong dependence on solar activity. Results also show that solar intensities higher during the rising phase of solar cycle. We also observed periodicities on solar flux index using wavelet analysis. Through this analysis, it was found that the power intensities of solar flux index show a high spectral variability.

  7. Retailer's optimal credit period and cycle time in a supply chain for deteriorating items with up-stream and down-stream trade credits

    Science.gov (United States)

    Mahata, Gour Chandra

    2015-09-01

    In practice, the supplier often offers the retailers a trade credit period and the retailer in turn provides a trade credit period to her/his customer to stimulate sales and reduce inventory. From the retailer's perspective, granting trade credit not only increases sales and revenue but also increases opportunity cost (i.e., the capital opportunity loss during credit period) and default risk (i.e., the percentage that the customer will not be able to pay off his/her debt obligations). Hence, how to determine credit period is increasingly recognized as an important strategy to increase retailer's profitability. Also, the selling items such as fruits, fresh fishes, gasoline, photographic films, pharmaceuticals and volatile liquids deteriorate continuously due to evaporation, obsolescence and spoilage. In this paper, we propose an economic order quantity model for the retailer where (1) the supplier provides an up-stream trade credit and the retailer also offers a down-stream trade credit, (2) the retailer's down-stream trade credit to the buyer not only increases sales and revenue but also opportunity cost and default risk, and (3) the selling items are perishable. Under these conditions, we model the retailer's inventory system as a profit maximization problem to determine the retailer's optimal replenishment decisions under the supply chain management. We then show that the retailer's optimal credit period and cycle time not only exist but also are unique. We deduce some previously published results of other researchers as special cases. Finally, we use some numerical examples to illustrate the theoretical results.

  8. CORONAL DYNAMIC ACTIVITIES IN THE DECLINING PHASE OF A SOLAR CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Minhwan; Choe, G. S. [Department of Astronomy and Space Science, Kyung Hee University, Yongin 17104 (Korea, Republic of); Woods, T. N. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Hong, Sunhak, E-mail: gchoe@khu.ac.kr [School of Space Research, Kyung Hee University, Yongin 17104 (Korea, Republic of)

    2016-12-10

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO /LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.

  9. CORONAL DYNAMIC ACTIVITIES IN THE DECLINING PHASE OF A SOLAR CYCLE

    International Nuclear Information System (INIS)

    Jang, Minhwan; Choe, G. S.; Woods, T. N.; Hong, Sunhak

    2016-01-01

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO /LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.

  10. Nonlinear solar cycle forecasting: theory and perspectives

    Science.gov (United States)

    Baranovski, A. L.; Clette, F.; Nollau, V.

    2008-02-01

    In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters - the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.

  11. Nonlinear solar cycle forecasting: theory and perspectives

    Directory of Open Access Journals (Sweden)

    A. L. Baranovski

    2008-02-01

    Full Text Available In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters – the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.

  12. CHROMOSPHERIC SUNSPOTS IN THE MILLIMETER RANGE AS OBSERVED BY THE NOBEYAMA RADIOHELIOGRAPH

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Kazumasa [National Institute of Information and Communications Technology, Koganei 184-8795, Tokyo (Japan); Koshiishi, Hideki [Aerospace Research and Development Directorate, Japan Aerospace Exploration Agency, Tsukuba 305-8505 (Japan); Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Nozawa, Satoshi; Miyawaki, Shun; Yoneya, Takuro, E-mail: kazumasa.iwai@nict.go.jp [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan)

    2016-01-10

    We investigate the upper chromosphere and the transition region of the sunspot umbra using the radio brightness temperature at 34 GHz (corresponding to 8.8 mm observations) as observed by the Nobeyama Radioheliograph (NoRH). Radio free–free emission in the longer millimeter range is generated around the transition region, and its brightness temperature yields the region's temperature and density distribution. We use the NoRH data at 34 GHz by applying the Steer-CLEAN image synthesis. These data and the analysis method enable us to investigate the chromospheric structures in the longer millimeter range with high spatial resolution and sufficient visibilities. We also perform simultaneous observations of one sunspot using the NoRH and the Nobeyama 45 m telescope operating at 115 GHz. We determine that 115 GHz emission mainly originates from the lower chromosphere while 34 GHz emission mainly originates from the upper chromosphere and transition region. These observational results are consistent with the radio emission characteristics estimated from current atmospheric models of the chromosphere. On the other hand, the observed brightness temperature of the umbral region is almost the same as that of the quiet region. This result is inconsistent with current sunspot models, which predict a considerably higher brightness temperature of the sunspot umbra at 34 GHz. This inconsistency suggests that the temperature of the region at which the 34 GHz radio emission becomes optically thick should be lower than that predicted by the models.

  13. On the evolution of magnetic and velocity fields of an originating sunspot group

    International Nuclear Information System (INIS)

    Bachmann, G.

    1978-01-01

    Magnetographic measurements were made to derive longitudinal magnetic field strengths, line-of-sight velocities and the brightness distribution in an originating sunspot group. These results and photographs of the group are used to compare the evaluation of a relatively simple active region with our present ideas about the evolution of active regions in general. We found that the total magnetic flux increased from about 4 to 20x10 20 Mx over three days. The downward flow of gas in regions with stronger magnetic fields is formed only after the magnetic field has already been bipolar for two days. The maximum velocity always occurred in the main spots of the preceding and the subsequent parts of the sunspot group. Transformation into a flow pattern, which looks like Evershed motion, is observed in the main preceding sunspot after the formation of the penumbra. The generation of new active regions by concentration and amplification of magnetic fields, under the action of supergranulation flow in photospheric layers, cannot play an important role. On the contrary, the behaviour of the active region is in agreement with the conception of rising flux tubes, out of which the gas flows down. Our observations confirm that a magnetic field strength, leading to the generation of sunspots, is attained earlier in the preceding part of the originating active region than in its subsequent part. A series of subflares occurred in the active region, when short-lived small magnetic structure elements emerged in the larger bipolar magnetic field. (author)

  14. Flow and magnetic field properties in the trailing sunspots of active region NOAA 12396

    Czech Academy of Sciences Publication Activity Database

    Verma, M.; Denker, C.; Boehm, F.; Balthasar, H.; Fischer, C.E.; Kuckein, C.; Gonzalez, N.B.; Berkefeld, T.; Collados Vera, M.; Diercke, A.; Feller, A.; Gonzalez Manrique, S. J.; Hofmann, A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Pator Yabar, A.; Rezaei, R.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Sobotka, Michal; Solanki, S.K.; Soltau, D.; Staude, J.; Strassmeier, K.G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.A.

    2016-01-01

    Roč. 337, č. 10 (2016), s. 1090-1098 ISSN 0004-6337. [Dynamic Sun - Exploring the Many Facets of Solar Eruptive Events. Potsdam, 26.10. 2015 -29.10. 2015 ] Institutional support: RVO:67985815 Keywords : Sun * magnetic fields * sunspots Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.916, year: 2016

  15. Corona magnetic field over sunspots estimated by m-wave observation

    International Nuclear Information System (INIS)

    Kurihara, Masahiro

    1974-01-01

    The shape of the magnetic field in corona was estimated from the observation of the type I storm occurred in the last decade of August, 1971. It was found from the observation with a 160 MHz interferometer at Mt. Nobeyama that at most three storm sources, which are called radio wave source, were produced. The radio wave sources were fixed above sunspots. The height of the radio wave sources was estimated to be 0.45 R from the photosphere. The sunspots under the radio wave sources can be classified to four sub-groups. Weakening of the magnetic field on the photosphere was found from the reduction of the area of some sub-group. The relation between the activity of type I storm and the intensity of the magnetic field of sunspots is qualitatively suggested. It is considered that the radio wave sources and the sunspots were connected by common magnetic force lines. The probable magnetic field in corona was presumed and is shown in a figure. An interesting point is that the direction of magnetic force lines inclined by about 30 0 outward to the vertical line to the photosphere surface. (Kato, T.)

  16. Physical Properties of Umbral Dots Observed in Sunspots: A Hinode Observation

    Science.gov (United States)

    Yadav, Rahul; Mathew, Shibu K.

    2018-04-01

    Umbral dots (UDs) are small-scale bright features observed in the umbral part of sunspots and pores. It is well established that they are manifestations of magnetoconvection phenomena inside umbrae. We study the physical properties of UDs in different sunspots and their dependence on decay rate and filling factor. We have selected high-resolution, G-band continuum filtergrams of seven sunspots from Hinode to study their physical properties. We have also used Michelson Doppler Imager (MDI) continuum images to estimate the decay rate of selected sunspots. An identification and tracking algorithm was developed to identify the UDs in time sequences. The statistical analysis of UDs exhibits an averaged maximum intensity and effective diameter of 0.26 I_{QS} and 270 km. Furthermore, the lifetime, horizontal speed, trajectory length, and displacement length (birth-death distance) of UDs are 8.19 minutes, 0.5 km s-1, 284 km, and 155 km, respectively. We also find a positive correlation between intensity-diameter, intensity-lifetime, and diameter-lifetime of UDs. However, UD properties do not show any significant relation with the decay rate or filling factor.

  17. Fine structure in sunspots. IV. Penumbral grains in speckle reconstucted images

    Czech Academy of Sciences Publication Activity Database

    Sobotka, Michal; Suetterlin, P.

    2001-01-01

    Roč. 380, č. 2 (2001), s. 714-718 ISSN 0004-6361 R&D Projects: GA AV ČR KSK2043105; GA AV ČR IAA3003903 Institutional research plan: CEZ:AV0Z1003909 Keywords : sun * sunspots Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.790, year: 2000

  18. Preliminary results from the orbiting solar observatory 8: Transition-zone dynamics over a sunspot

    International Nuclear Information System (INIS)

    Bruner, E.C. Jr.; Chipman, E.G.; Lites, B.W.; Rottman, G.J.; Shine, R.A.; Athay, R.G.; White, O.R.

    1976-01-01

    The University of Colorado experiment aboard OSO-8 observed the C IV 1548 A line in the bright plume over a sunspot. Transient redshifts at 5 minute intervals were studied, but the expected phenomena associated with simple Alfven wave effects were not observed

  19. Temperature mapping of sunspots and pores from speckle reconstructed three colour photometry

    NARCIS (Netherlands)

    Sütterlin, P.; Wiehr, E.

    1998-01-01

    The two-dimensional temperature distribution in a highly structured sunspot and in two small umbrae is determined from a three-colour photometry in narrow spectral continua. Disturbing influences from the earth’s atmosphere are removed by speckle masking techniques, yielding a spatial resolution

  20. A single preovulatory administration of ulipristal acetate affects the decidualization process of the human endometrium during the receptive period of the menstrual cycle.

    Science.gov (United States)

    Lira-Albarrán, Saúl; Durand, Marta; Barrera, David; Vega, Claudia; Becerra, Rocio García; Díaz, Lorenza; García-Quiroz, Janice; Rangel, Claudia; Larrea, Fernando

    2018-04-27

    In order to get further information on the effects of ulipristal acetate (UPA) upon the process of decidualization of endometrium, a functional analysis of the differentially expressed genes in endometrium (DEG) from UPA treated-versus control-cycles of normal ovulatory women was performed. A list of 1183 endometrial DEG, from a previously published study by our group, was submitted to gene ontology, gene enrichment and ingenuity pathway analyses (IPA). This functional analysis showed that decidualization was a biological process overrepresented. Gene set enrichment analysis identified LIF, PRL, IL15 and STAT3 among the most down-regulated genes within the JAK STAT canonical pathway. IPA showed that decidualization of uterus was a bio-function predicted as inhibited by UPA. The results demonstrated that this selective progesterone receptor modulator, when administered during the periovulatory phase of the menstrual cycle, may affect the molecular mechanisms leading to endometrial decidualization in response to progesterone during the period of maximum embryo receptivity. Copyright © 2018. Published by Elsevier B.V.

  1. Methanol to olefin Conversion on HSAPO-34 zeolite from periodic density functional theory calculations: a complete cycle of side chain hydrocarbon pool mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.M.; Wang, Y.D.; Xie, Z.K.; Liu, Z.P. [SINOPEC, Shanghai (China)

    2009-03-15

    For its unique position in the coal chemical industry, the methanol to olefin (MTO) reaction has been a hot topic in zeolite catalysis. Due to the complexities of catalyst structure and reaction networks, many questions such as how the olefin chain is built from methanol remain elusive. On the basis of periodic density functional theory calculations, this work establishes the first complete catalytic cycle for MTO reaction via hexamethylbenzene (HMB) trapped in HSAPO-34 zeolite based on the so-called side chain hydrocarbon pool mechanism. The cycle starts from the methylation of HMB that leads to heptamethylbenzenium ion (heptaMB{sup +}) intermediate. This is then followed by the growth of side chain via repeated deprotonation of benzenium ions and methylation of the exocyclic double bond. Ethene and propene can finally be released from the side ethyl and isopropyl groups of benzenium ions by deprotonation and subsequent protonation steps. We demonstrate that (i) HMB/HSAPO-34 only yields propene as the primary product based on the side chain hydrocarbon pool mechanism and (ii) an indirect proton-shift step mediated by water that is always available in the system is energetically more favorable than the traditionally regarded internal hydrogen-shift step. Finally, the implications of our results toward understanding the effect of acidity of zeolite on MTO activity are also discussed.

  2. Your Menstrual Cycle

    Science.gov (United States)

    ... your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... that take place over the weeks in your cycle. Want to know what happens on each day ...

  3. Geomagnetic storms and their sources on the sun:the rising phase of the sunspot cycle

    Directory of Open Access Journals (Sweden)

    Takao Saito

    2013-03-01

    Full Text Available Solar phenomena, including solar flares and coronal holes, are considered in the context of a NEWS coordinate system, obtained by application of the heliographic and heliomagnetic coordinate systems to the solar latitude and longitude, respectively. By expressing the occurrence of solar phenomena in terms of NEWS coordinates, we discovered that solar flares tend to converge in the NE and SW quadrants of the solar disk, where they act as sources of sporadic storms. Meanwhile, coronal holes converge to solar longitudes of 0° and 180°, where they are sources of recurrent storms. Because of their concentration in the NE- and SW-quadrants, this correlation is referred to as the 'NEWS law'. The neutral line of the source surface shows a beautiful single wave in its declining phase, while it tends to show a double wave in the rising phase. Solar rotation numbers 2118 to 2119, where the neutral line exhibited two complicated asymmetric waves in both the N-S and S-W directions, were chosen for detailed analysis. Notwithstanding such an extremely complicated case, the NEWS law is satisfied when the double wave is separated into its two single-wave parts.

  4. Communicating the science of the 11-year sunspot cycle to the general public

    Science.gov (United States)

    Choudhuri, A. R.

    2015-03-01

    Astrophysics is one branch of science which excites the imagination of the general public. Pioneer science popularizers like George Gamow and Fred Hoyle wrote on different aspects of astrophysics. However, of late, we see a trend which I find disturbing. While it has become extremely fashionable to write popular science books on cosmology, other areas of astrophysics are grossly neglected.

  5. Periodic isolation of the southern coastal plain of South Africa and the evolution of modern humans over late Quaternary glacial to interglacial cycles

    Science.gov (United States)

    Compton, J. S.

    2012-04-01

    Humans evolved in Africa, but where in Africa and by what mechanisms remain unclear. The evolution of modern humans over the last million years is associated with the onset of major global climate fluctuations, glacial to interglacial cycles, related to the build up and melting of large ice sheets in the Northern Hemisphere. During interglacial periods, such as today, warm and wet climates favored human expansion but during cold and dry glacial periods conditions were harsh and habitats fragmented. These large climate fluctuations periodically expanded and contracted African ecosystems and led to human migrations to more hospitable glacial refugia. Periodic isolation of relatively small numbers of humans may have allowed for their rapid evolutionary divergence from the rest of Africa. During climate transitions these divergent groups may have then dispersed and interbred with other groups (hybridization). Two areas at the opposite ends of Africa stand out as regions that were periodically isolated from the rest of Africa: North Africa (the Maghreb) and the southern coastal plain (SCP) of South Africa. The Maghreb is isolated by the Sahara Desert which periodically greens and is reconnected to the rest of Africa during the transition from glacial to interglacial periods. The SCP of South Africa is isolated from the rest of Africa by the rugged mountains of the Cape Fold Belt associated with inedible vegetation and dry climates to the north. The SCP is periodically opened when sea level falls by up to 130 m during glacial maxima to expose the present day submerged inner continental shelf. A five-fold expansion of the SCP receiving more rainfall in glacial periods may have served as a refuge to humans and large migratory herds. The expansive glacial SCP habitat abruptly contracts, by as much as one-third in 300 yr, during the rapid rise in sea level associated with glacial terminations. Rapid flooding may have increased population density and competition on the SCP to

  6. Research on the stages of macrocycle of motive qualities of bicyclists 12-13 years on the type of build in the period of becoming of ovarian-menstrual cycle

    Directory of Open Access Journals (Sweden)

    Prudnikova M.S.

    2010-12-01

    Full Text Available Motive qualities of young sportswomen are considered in the period of becoming specific biological cycle. In researches took part 45 young bicyclists in age of 12-15 years. It is rotined that under act of the physical loadings the type of build influences on the period of becoming ovarian-menstrual cycle. It is marked that the minimum indexes of motive qualities for girls were observed in becoming of genesial function of womanish organism. It is set that application of specific tests in the select type of sport allowed to define the level of preparedness and becoming ovarian-menstrual cycle.

  7. A Test of the Active-Day Fraction Method of Sunspot Group Number Calibration: Dependence on the Level of Solar Activity

    Science.gov (United States)

    Willamo, T.; Usoskin, I. G.; Kovaltsov, G. A.

    2018-04-01

    The method of active-day fraction (ADF) was proposed recently to calibrate different solar observers to standard observational conditions. The result of the calibration may depend on the overall level of solar activity during the observational period. This dependency is studied quantitatively using data of the Royal Greenwich Observatory by formally calibrating synthetic pseudo-observers to the full reference dataset. It is shown that the sunspot group number is precisely estimated by the ADF method for periods of moderate activity, may be slightly underestimated by 0.5 - 1.5 groups ({≤} 10%) for strong and very strong activity, and is strongly overestimated by up to 2.5 groups ({≤} 30%) for weak-to-moderate activity. The ADF method becomes inapplicable for the periods of grand minima of activity. In general, the ADF method tends to overestimate the overall level of activity and to reduce the long-term trends.

  8. Solar spectral irradiance variability of some chromospheric emission lines through the solar activity cycles 21-23

    Directory of Open Access Journals (Sweden)

    Göker Ü.D.

    2017-01-01

    Full Text Available A study of variations of solar spectral irradiance (SSI in the wave-length ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV spectral lines and international sunspot number (ISSN from interactive data centers such as SME (NSSDC, UARS (GDAAC, SORCE (LISIRD and SIDC, respectively. We reduced these data by using the MATLsoftware package. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm spectral lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar activity cycles (SACs 23 and 24. We also compared our results with the variations of solar activity indices obtained by the ground-based telescopes. Therefore, we found that plage regions decrease while facular areas are increasing in SAC 23. However, the decrease in plage regions is seen in small sunspot groups (SGs, contrary to this, these regions in large SGs are comparable to previous SACs or even larger as is also seen in facular areas. Nevertheless, negative correlations between ISSN and SSI data indicate that these variations are in close connection with the classes of sunspots/SGs, faculae and plage regions. Finally, we applied the time series analysis of spectral lines corresponding to the wavelengths 121.5 nm-300.5 nm and made comparisons with the ISSN data. We found an unexpected increase in the 298.5 nm line for the Fe II ion. The variability of Fe II ion 298.5 nm line is in close connection with the facular areas and plage regions, and the sizes of these solar surface indices play an important role for the SSI variability, as well. So, we compared the connection between the sizes of faculae and plage regions, sunspots/SGs, chemical elements and SSI variability. Our future work will be the theoretical study of this connection and developing of a corresponding model.

  9. Phase synchronization of baroclinic waves in a differentially heated rotating annulus experiment subject to periodic forcing with a variable duty cycle.

    Science.gov (United States)

    Read, P L; Morice-Atkinson, X; Allen, E J; Castrejón-Pita, A A

    2017-12-01

    A series of laboratory experiments in a thermally driven, rotating fluid annulus are presented that investigate the onset and characteristics of phase synchronization and frequency entrainment between the intrinsic, chaotic, oscillatory amplitude modulation of travelling baroclinic waves and a periodic modulation of the (axisymmetric) thermal boundary conditions, subject to time-dependent coupling. The time-dependence is in the form of a prescribed duty cycle in which the periodic forcing of the boundary conditions is applied for only a fraction δ of each oscillation. For the rest of the oscillation, the boundary conditions are held fixed. Two profiles of forcing were investigated that capture different parts of the sinusoidal variation and δ was varied over the range 0.1≤δ≤1. Reducing δ was found to act in a similar way to a reduction in a constant coupling coefficient in reducing the width of the interval in forcing frequency or period over which complete synchronization was observed (the "Arnol'd tongue") with respect to the detuning, although for the strongest pulse-like forcing profile some degree of synchronization was discernible even at δ=0.1. Complete phase synchronization was obtained within the Arnol'd tongue itself, although the strength of the amplitude modulation of the baroclinic wave was not significantly affected. These experiments demonstrate a possible mechanism for intraseasonal and/or interannual "teleconnections" within the climate system of the Earth and other planets that does not rely on Rossby wave propagation across the planet along great circles.

  10. The Sunspot Number and beyond : reconstructing detailed solar information over centuries

    Science.gov (United States)

    Lefevre, L.

    2014-12-01

    With four centuries of solar evolution, the International Sunspot Number (SSN) forms the longest solar time series currently available. It provides an essential reference for understanding and quantifying how the solar output has varied over decades and centuries and thus for assessing the variations of the main natural forcing on the Earth climate. Because of its importance, this unique time-series must be closely monitored for any possible biases and drifts. Here, we report about recent disagreements between solar indices, for example the sunspot sumber and the 10.7cm radio flux. Recent analyses indicate that while part of this divergence may be due to a calibration drift in the SSN, it also results from an intrinsic change in the global magnetic parameters of sunspots and solar active regions, suggesting a possible transition to a new activity regime. Going beyond the SSN series, in the framework of the TOSCA (www.cost-tosca.eu/) and SOLID (projects.pmodwrc.ch/solid/) projects, we produced a survey of all existing catalogs providing detailed sunspot information (Lefevre & Clette, 2014:10.1007/s11207-012-0184-5) and we also located different primary solar images and drawing collections that can be exploitable to complement the existing catalogs. These are first steps towards the construction of a multi-parametric time series of multiple sunspot and sunspot group properties over more than a century, allowing to reconstruct and extend the current 1-D SSN series. By bringing new spatial, morphological and evolutionary information, such a data set should bring major advances for the modeling of the solar dynamo and solar irradiance. We will present here the current status of this work. The preliminary version catalog now extends over the last 150 years. It makes use of data from DPD (http://fenyi.solarobs.unideb.hu/DPD/index.html), from the Uccle Solar Equatorial Table (USET:http://sidc.oma.be/uset/) operated by the Royal Obeservatory of Belgium, the Greenwich

  11. A model of a sunspot chromosphere based on OSO 8 observations

    Science.gov (United States)

    Lites, B. W.; Skumanich, A.

    1982-01-01

    OSO 8 spectrometer observations of the H I, Mg II, and Ca II resonance lines of a large quiet sunspot during November 16-17, 1975, along with a C IV line of that event obtained by a ground-based spectrometer, are analyzed together with near-simultaneous ground-based Stokes measurements to yield an umbral chromosphere and transition region model. Features of this model include a chromosphere that is effectively thin in the resonance lines of H I and Mg II, while being saturated in Ca II, and an upper chromospheric structure similar to that of quiet-sun models. The similarity of the upper chromosphere of the sunspot umbra to the quiet-sun chromosphere suggests that the intense magnetic field plays only a passive role in the chromospheric heating mechanism, and the observations cited indicate that solar-type stars with large areas of ordered magnetic flux would not necessarily exhibit extremely active chromosphere.

  12. The chromosphere above a δ-sunspot in the presence of fan-shaped jets

    Science.gov (United States)

    Robustini, Carolina; Leenaarts, Jorrit; de la Cruz Rodríguez, Jaime

    2018-01-01

    Context. Delta-sunspots are known to be favourable locations for fast and energetic events like flares and coronal mass ejections. The photosphere of this sunspot type has been thoroughly investigated in the past three decades. The atmospheric conditions in the chromosphere are not as well known, however. Aims: This study is focused on the chromosphere of a δ-sunspot that harbours a series of fan-shaped jets in its penumbra. The aim of this study is to establish the magnetic field topology and the temperature distribution in the presence of jets in the photosphere and the chromosphere. Methods: We use data from the Swedish 1m Solar Telescope (SST) and the Solar Dynamics Observatory. We invert the spectropolarimetric Fe I 6302 Å and Ca II 8542 Å data from the SST using the non-LTE inversion code NICOLE to estimate the magnetic field configuration, temperature, and velocity structure in the chromosphere. Results: A loop-like magnetic structure is observed to emerge in the penumbra of the sunspot. The jets are launched from this structure. Magnetic reconnection between this emerging field and the pre-existing vertical field is suggested by hot plasma patches on the interface between the two fields. The height at which the reconnection takes place is located between log τ500 = -2 and log τ500 = -3. The magnetic field vector and the atmospheric temperature maps show a stationary configuration during the whole observation. Movies associated to Figs. 3-5 are available at http://www.aanda.org

  13. Fully Automated Sunspot Detection and Classification Using SDO HMI Imagery in MATLAB

    Science.gov (United States)

    2014-03-27

    initiating the java program scripted to communicate with the SOON telescope used for continual observation of the sun. The SOON telescope is used at...proximity of spots refers to the angular separation between different spots that could make up a group. The area of each sunspot means the total area...degrees and the different magnetic polarities of each spot being considered. For a spot pair that has the same polarity and small angular separation

  14. SMALL-SCALE AND GLOBAL DYNAMOS AND THE AREA AND FLUX DISTRIBUTIONS OF ACTIVE REGIONS, SUNSPOT GROUPS, AND SUNSPOTS: A MULTI-DATABASE STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz-Jaramillo, Andrés; Windmueller, John C.; Amouzou, Ernest C.; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Senkpeil, Ryan R. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Tlatov, Andrey G. [Kislovodsk Mountain Astronomical Station of the Pulkovo Observatory, Kislovodsk 357700 (Russian Federation); Nagovitsyn, Yury A. [Pulkovo Astronomical Observatory, Russian Academy of Sciences, St. Petersburg 196140 (Russian Federation); Pevtsov, Alexei A. [National Solar Observatory, Sunspot, NM 88349 (United States); Chapman, Gary A.; Cookson, Angela M. [San Fernando Observatory, Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330 (United States); Yeates, Anthony R. [Department of Mathematical Sciences, Durham University, South Road, Durham DH1 3LE (United Kingdom); Watson, Fraser T. [National Solar Observatory, Tucson, AZ 85719 (United States); Balmaceda, Laura A. [Institute for Astronomical, Terrestrial and Space Sciences (ICATE-CONICET), San Juan (Argentina); DeLuca, Edward E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Martens, Petrus C. H., E-mail: munoz@solar.physics.montana.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)

    2015-02-10

    In this work, we take advantage of 11 different sunspot group, sunspot, and active region databases to characterize the area and flux distributions of photospheric magnetic structures. We find that, when taken separately, different databases are better fitted by different distributions (as has been reported previously in the literature). However, we find that all our databases can be reconciled by the simple application of a proportionality constant, and that, in reality, different databases are sampling different parts of a composite distribution. This composite distribution is made up by linear combination of Weibull and log-normal distributions—where a pure Weibull (log-normal) characterizes the distribution of structures with fluxes below (above) 10{sup 21}Mx (10{sup 22}Mx). Additionally, we demonstrate that the Weibull distribution shows the expected linear behavior of a power-law distribution (when extended to smaller fluxes), making our results compatible with the results of Parnell et al. We propose that this is evidence of two separate mechanisms giving rise to visible structures on the photosphere: one directly connected to the global component of the dynamo (and the generation of bipolar active regions), and the other with the small-scale component of the dynamo (and the fragmentation of magnetic structures due to their interaction with turbulent convection)

  15. MEASUREMENTS OF ABSORPTION, EMISSIVITY REDUCTION, AND LOCAL SUPPRESSION OF SOLAR ACOUSTIC WAVES IN SUNSPOTS

    International Nuclear Information System (INIS)

    Chou, D.-Y.; Liang, Z.-C.; Yang, M.-H.; Zhao Hui; Sun, M.-T.

    2009-01-01

    The power of solar acoustic waves in magnetic regions is lower relative to the quiet Sun. Absorption, emissivity reduction, and local suppression of acoustic waves contribute to the observed power reduction in magnetic regions. We propose a model for the energy budget of acoustic waves propagating through a sunspot in terms of the coefficients of absorption, emissivity reduction, and local suppression of the sunspot. Using the property that the waves emitted along the wave path between two points have no correlation with the signal at the starting point, we can separate the effects of these three mechanisms. Applying this method to helioseismic data filtered with direction and phase-velocity filters, we measure the fraction of the contribution of each mechanism to the power deficit in the umbra of the leading sunspot of NOAA 9057. The contribution from absorption is 23.3 ± 1.3%, emissivity reduction 8.2 ± 1.4%, and local suppression 68.5 ± 1.5%, for a wave packet corresponding to a phase velocity of 6.98 x 10 -5 rad s -1 .

  16. Fuel cycles

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1983-05-01

    AECL publications, from the open literature, on fuels and fuel cycles used in CANDU reactors are listed in this bibliography. The accompanying index is by subject. The bibliography will be brought up to date periodically

  17. Phytoplankton Biomass Dynamics in the Strait of Malacca within the Period of the SeaWiFS Full Mission: Seasonal Cycles, Interannual Variations and Decadal-Scale Trends

    Directory of Open Access Journals (Sweden)

    Eko Siswanto

    2014-03-01

    Full Text Available Seasonal cycles, interannual variations and decadal trends of Sea-viewing Wide Field-of-view Sensor (SeaWiFS-retrieved chlorophyll-a concentration (Chl-a in the Strait of Malacca (SM were investigated with reconstructed, cloud-free SeaWiFS Chl-a during the period of the SeaWiFS full mission (September 1997 to December 2010. Pixel-based non-parametric correlations of SeaWiFS Chl-a on environmental variables were used to identify the probable causes of the observed spatio-temporal variations of SeaWiFS Chl-a in northern, middle and southern regions of the SM. Chl-a was high (low during the northeast (southwest monsoon. The principal causes of the seasonality were wind-driven vertical mixing in the northern region and wind-driven coastal upwelling and possibly river discharges in the middle region. Among the three regions, the southern region showed the largest interannual variations of Chl-a. These variations were associated with the El Niño/Southern Oscillation (ENSO and river runoff. Interannual variations of Chl-a in the middle and northern regions were more responsive to the Indian Ocean Dipole and ENSO, respectively, with atmospheric deposition being the most important driver. The most significant decadal-scale trend of increasing Chl-a was in the southern region; the trend was moderate in the middle region. This increasing trend was probably caused by environmental changes unrelated to the variables investigated in this study.

  18. A PROPOSED PARADIGM FOR SOLAR CYCLE DYNAMICS MEDIATED VIA TURBULENT PUMPING OF MAGNETIC FLUX IN BABCOCK–LEIGHTON-TYPE SOLAR DYNAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Hazra, Soumitra; Nandy, Dibyendu [Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata (India)

    2016-11-20

    At present, the Babcock–Leighton flux transport solar dynamo models appear to be the most promising models for explaining diverse observational aspects of the sunspot cycle. The success of these flux transport dynamo models is largely dependent upon a single-cell meridional circulation with a deep equatorward component at the base of the Sun’s convection zone. However, recent observations suggest that the meridional flow may in fact be very shallow (confined to the top 10% of the Sun) and more complex than previously thought. Taken together, these observations raise serious concerns on the validity of the flux transport paradigm. By accounting for the turbulent pumping of magnetic flux, as evidenced in magnetohydrodynamic simulations of solar convection, we demonstrate that flux transport dynamo models can generate solar-like magnetic cycles even if the meridional flow is shallow. Solar-like periodic reversals are recovered even when meridional circulation is altogether absent. However, in this case, the solar surface magnetic field dynamics does not extend all the way to the polar regions. Very importantly, our results demonstrate that the Parker–Yoshimura sign rule for dynamo wave propagation can be circumvented in Babcock–Leighton dynamo models by the latitudinal component of turbulent pumping, which can generate equatorward propagating sunspot belts in the absence of a deep, equatorward meridional flow. We also show that variations in turbulent pumping coefficients can modulate the solar cycle amplitude and periodicity. Our results suggest the viability of an alternate magnetic flux transport paradigm—mediated via turbulent pumping—for sustaining solar-stellar dynamo action.

  19. A PROPOSED PARADIGM FOR SOLAR CYCLE DYNAMICS MEDIATED VIA TURBULENT PUMPING OF MAGNETIC FLUX IN BABCOCK–LEIGHTON-TYPE SOLAR DYNAMOS

    International Nuclear Information System (INIS)

    Hazra, Soumitra; Nandy, Dibyendu

    2016-01-01

    At present, the Babcock–Leighton flux transport solar dynamo models appear to be the most promising models for explaining diverse observational aspects of the sunspot cycle. The success of these flux transport dynamo models is largely dependent upon a single-cell meridional circulation with a deep equatorward component at the base of the Sun’s convection zone. However, recent observations suggest that the meridional flow may in fact be very shallow (confined to the top 10% of the Sun) and more complex than previously thought. Taken together, these observations raise serious concerns on the validity of the flux transport paradigm. By accounting for the turbulent pumping of magnetic flux, as evidenced in magnetohydrodynamic simulations of solar convection, we demonstrate that flux transport dynamo models can generate solar-like magnetic cycles even if the meridional flow is shallow. Solar-like periodic reversals are recovered even when meridional circulation is altogether absent. However, in this case, the solar surface magnetic field dynamics does not extend all the way to the polar regions. Very importantly, our results demonstrate that the Parker–Yoshimura sign rule for dynamo wave propagation can be circumvented in Babcock–Leighton dynamo models by the latitudinal component of turbulent pumping, which can generate equatorward propagating sunspot belts in the absence of a deep, equatorward meridional flow. We also show that variations in turbulent pumping coefficients can modulate the solar cycle amplitude and periodicity. Our results suggest the viability of an alternate magnetic flux transport paradigm—mediated via turbulent pumping—for sustaining solar-stellar dynamo action.

  20. The solar activity cycle physical causes and consequences

    CERN Document Server

    Hudson, Hugh; Petrovay, Kristóf; Steiger, Rudolf

    2015-01-01

    A collection of papers edited by four experts in the field, this book sets out to describe the way solar activity is manifested in observations of the solar interior, the photosphere, the chromosphere, the corona and the heliosphere. The 11-year solar activity cycle, more generally known as the sunspot cycle, is a fundamental property of the Sun.  This phenomenon is the generation and evolution of magnetic fields in the Sun’s convection zone, the photosphere.  It is only by the careful enumeration and description of the phenomena and their variations that one can clarify their interdependences.   The sunspot cycle has been tracked back about four centuries, and it has been recognized that to make this data set a really useful tool in understanding how the activity cycle works and how it can be predicted, a very careful and detailed effort is needed to generate sunspot numbers.  This book deals with this topic, together with several others that present related phenomena that all indicate the physical pr...

  1. SOHO sees right through the Sun, and finds sunspots on the far side

    Science.gov (United States)

    2000-03-01

    The story is told today in the journal Science by Charles Lindsey of Tucson, Arizona, and Doug Braun of Boulder, Colorado. They realised that the analytical witchcraft called helioseismic holography might open a window right through the Sun. And the technique worked when they used it to decode waves seen on the visible surface by one of SOHO's instruments, the Michelson Doppler Imager, or MDI. "We've known for ten years that in theory we could make the Sun transparent all the way to the far side," said Charles Lindsey. "But we needed observations of exceptional quality. In the end we got them, from MDI on SOHO." For more than 100 years scientists have been aware that groups of dark sunspots on the Sun's visible face are often the scene of flares and other eruptions. Nowadays they watch the Sun more closely than ever, because modern systems are much more vulnerable to solar disturbances than old-style technology was. The experts can still be taken by surprise, because the Sun turns on its axis. A large group of previously hidden sunspots can suddenly swing into view on the eastern (left-hand) edge of the Sun. It may already be blazing away with menacing eruptions. With a far-side preview of sunspots, nasty shocks for the space weather forecasters may now be avoidable. Last year, French and Finnish scientists used SWAN, another instrument on SOHO, to detect activity on the far side. They saw an ultraviolet glow lighting up gas in the Solar System beyond the Sun, and moving across the sky like a lighthouse beam as the Sun rotated. The method used by Lindsey and Braun with MDI data is completely different, and it pinpoints the source of the activity on the far side. Solar seismology chalks up another success Detection of sound waves reverberating through the Sun opened its gassy interior for investigation, in much the same way as seismologists learned to explore the Earth's rocky interior with earthquake waves. Using special telescopes on the ground and in space

  2. Records of auroral candidates and sunspots in Rikkokushi, chronicles of ancient Japan from early 7th century to 887

    Science.gov (United States)

    Hayakawa, Hisashi; Iwahashi, Kiyomi; Tamazawa, Harufumi; Ebihara, Yusuke; Kawamura, Akito Davis; Isobe, Hiroaki; Namiki, Katsuko; Shibata, Kazunari

    2017-12-01

    We present the results of the surveys on sunspots and auroral candidates in Rikkokushi, Japanese official histories from the early 7th century to 887, to review the solar and auroral activities. In total, we found one sunspot record and 13 auroral candidates in Rikkokushi. We then examine the records of the sunspots and auroral candidates, compare the auroral candidates with the lunar phase to estimate their reliability, and compare the records of the sunspots and auroral candidates with the contemporary total solar irradiance reconstructed from radioisotope data. We also identify the locations of the observational sites to review possible equatorward expansion of the auroral oval. These discussions suggest a major gap in auroral candidates from the late 7th to early 9th centuries, which includes the candidate of the grand minimum reconstructed from the radioisotope data, a similar tendency as the distributions of sunspot records in contemporary China, and a relatively high magnetic latitude of observational sites with a higher potential for observing aurorae more frequently than at present.

  3. E2F1-Mediated Upregulation of p19INK4d Determines Its Periodic Expression during Cell Cycle and Regulates Cellular Proliferation

    OpenAIRE

    Carcagno, Abel L.; Marazita, Mariela C.; Ogara, María F.; Ceruti, Julieta M.; Sonzogni, Silvina V.; Scassa, María E.; Giono, Luciana E.; Cánepa, Eduardo T.

    2011-01-01

    Background: A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality o...

  4. Mid-Term Quasi-Periodicities and Solar Cycle Variation of the White-Light Corona from 18.5 Years (1996.0 - 2014.5) of LASCO Observations

    Science.gov (United States)

    Barlyaeva, T.; Lamy, P.; Llebaria, A.

    2015-07-01

    We report on the analysis of the temporal evolution of the solar corona based on 18.5 years (1996.0 - 2014.5) of white-light observations with the SOHO/LASCO-C2 coronagraph. This evolution is quantified by generating spatially integrated values of the K-corona radiance, first globally, then in latitudinal sectors. The analysis considers time series of monthly values and 13-month running means of the radiance as well as several indices and proxies of solar activity. We study correlation, wavelet time-frequency spectra, and cross-coherence and phase spectra between these quantities. Our results give a detailed insight on how the corona responds to solar activity over timescales ranging from mid-term quasi-periodicities (also known as quasi-biennial oscillations or QBOs) to the long-term 11 year solar cycle. The amplitude of the variation between successive solar maxima and minima (modulation factor) very much depends upon the strength of the cycle and upon the heliographic latitude. An asymmetry is observed during the ascending phase of Solar Cycle 24, prominently in the royal and polar sectors, with north leading. Most prominent QBOs are a quasi-annual period during the maximum phase of Solar Cycle 23 and a shorter period, seven to eight months, in the ascending and maximum phases of Solar Cycle 24. They share the same properties as the solar QBOs: variable periodicity, intermittency, asymmetric development in the northern and southern solar hemispheres, and largest amplitudes during the maximum phase of solar cycles. The strongest correlation of the temporal variations of the coronal radiance - and consequently the coronal electron density - is found with the total magnetic flux. Considering that the morphology of the solar corona is also directly controlled by the topology of the magnetic field, this correlation reinforces the view that they are intimately connected, including their variability at all timescales.

  5. On Solar Granulations, Limb Darkening, and Sunspots: Brief Insights in Remembrance of Father Angelo Secchi

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available Father Angelo Secchi used the existence of solar granulation as a central line of rea- soning when he advanced that the Sun was a gaseous body with a photosphere contain- ing incandescent particulate matter (Secchi A. Sulla Struttura della Fotosfera Solare. Bullettino Meteorologico dell’Osservatorio del Collegio Romano , 30 November 1864, v.3(11, 1–3. Secchi saw the granules as condensed matter emitting the photospheric spectrum, while the darkened intergranular lanes conveyed the presence of a gaseous solar interior. Secchi also considered the nature of sunspots and limb darkening. In the context of modern solar models, opacity arguments currently account for the emis- sive properties of the photosphere. Optical depth is thought to explain limb darkening. Both temperature variations and magnetic fields are invoked to justify the weakened emissivities of sunspots, even though the presence of static magnetic fields in materi- als is not usually associated with modified emissivity. Conversely, within the context of a liquid metallic hydrogen solar model, the appearance of granules, limb darkening, and sunspots can be elegantly understood through the varying directional emissivity of condensed matter. A single explanation is applicable to all three phenomena. Granular contrast can be directly associated with the generation of limb darkening. Depending on size, granules can be analyzed by considering Kolmogoroff’s formulations and B ́ enard convection, respectively, both of which were observed using incompressible liquids, not gases. Granules follow the 2-dimensional space filling laws of Aboav-Weiner and Lewis. Their adherence to these structural laws provides supportive evidence that the granular surface of the Sun represents elements which can only be constructed from condensed matter. A gaseous Sun cannot be confined to a 2-dimensional framework. Mesogranules, supergranules, and giant cells constitute additional entities which further

  6. The Formation of a Sunspot Penumbra Sector in Active Region NOAA 12574

    Science.gov (United States)

    Li, Qiaoling; Yan, Xiaoli; Wang, Jincheng; Kong, DeFang; Xue, Zhike; Yang, Liheng; Cao, Wenda

    2018-04-01

    We present a particular case of the formation of a penumbra sector around a developing sunspot in the active region NOAA 12574 on 2016 August 11 by using the high-resolution data observed by the New Solar Telescope at the Big Bear Solar Observatory and the data acquired by the Helioseismic and Magnetic Imager and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory satellite. Before the new penumbra sector formed, the developing sunspot already had two umbrae with some penumbral filaments. The penumbra sector gradually formed at the junction of two umbrae. We found that the formation of the penumbra sector can be divided into two stages. First, during the initial stage of penumbral formation, the region where the penumbra sector formed always appeared blueshifted in a Dopplergram. The area, mean transverse magnetic field strength, and total magnetic flux of the umbra and penumbra sector all increased with time. The initial penumbral formation was associated with magnetic emergence. Second, when the penumbra sector appeared, the magnetic flux and area of the penumbra sector increased after the umbra’s magnetic flux and area decreased. These results indicate that the umbra provided magnetic flux for penumbral development after the penumbra sector appeared. We also found that the newly formed penumbra sector was associated with sunspot rotation. Based on these findings, we suggest that the penumbra sector was the result of the emerging flux that was trapped in the photosphere at the initial stage of penumbral formation, and when the rudimentary penumbra formed, the penumbra sector developed at the cost of the umbra.

  7. SOLAR CYCLE PROPAGATION, MEMORY, AND PREDICTION: INSIGHTS FROM A CENTURY OF MAGNETIC PROXIES

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Jaramillo, Andres; DeLuca, Edward E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Dasi-Espuig, Maria [Max-Planck-Institut fuer Sonnensystemforschung, D-37191 Katlenburg-Lindau (Germany); Balmaceda, Laura A., E-mail: amunoz@cfa.harvard.edu, E-mail: edeluca@cfa.harvard.edu, E-mail: dasi@mps.mpg.de, E-mail: lbalmaceda@icate-conicet.gob.ar [Institute for Astronomical, Terrestrial and Space Sciences (ICATE-CONICET), San Juan (Argentina)

    2013-04-20

    The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. A major contributor to the disagreement is the lack of direct long-term databases covering different components of the solar magnetic field (toroidal versus poloidal). Here, we use sunspot area and polar faculae measurements spanning a full century (as our toroidal and poloidal field proxies) to study solar cycle propagation, memory, and prediction. Our results substantiate predictions based on the polar magnetic fields, whereas we find sunspot area to be uncorrelated with cycle amplitude unless multiplied by area-weighted average tilt. This suggests that the joint assimilation of tilt and sunspot area is a better choice (with aims to cycle prediction) than sunspot area alone, and adds to the evidence in favor of active region emergence and decay as the main mechanism of poloidal field generation (i.e., the Babcock-Leighton mechanism). Finally, by looking at the correlation between our poloidal and toroidal proxies across multiple cycles, we find solar cycle memory to be limited to only one cycle.

  8. THE FORMATION OF AN INVERSE S-SHAPED ACTIVE-REGION FILAMENT DRIVEN BY SUNSPOT MOTION AND MAGNETIC RECONNECTION

    Energy Technology Data Exchange (ETDEWEB)

    Yan, X. L.; Xue, Z. K.; Wang, J. C.; Yang, L. H. [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Priest, E. R. [Mathematics Institute, University of St Andrews, St Andrews, KY16 9SS (United Kingdom); Guo, Q. L., E-mail: yanxl@ynao.ac.cn [College of Mathematics Physics and Information Engineering, Jiaxing University, Jiaxing 314001 (China)

    2016-11-20

    We present a detailed study of the formation of an inverse S-shaped filament prior to its eruption in active region NOAA 11884 from 2013 October 31 to November 2. In the initial stage, clockwise rotation of a small positive sunspot around the main negative trailing sunspot formed a curved filament. Then the small sunspot cancelled with the negative magnetic flux to create a longer active-region filament with an inverse S-shape. At the cancellation site a brightening was observed in UV and EUV images and bright material was transferred to the filament. Later the filament erupted after cancellation of two opposite polarities below the upper part of the filament. Nonlinear force-free field extrapolation of vector photospheric fields suggests that the filament may have a twisted structure, but this cannot be confirmed from the current observations.

  9. Relation of flare activity to the approach and separation of sunspots in an active region and to its magnetic properties

    International Nuclear Information System (INIS)

    Markova, E.

    1978-01-01

    The relation between the flare activity of active regions within the scope of a large complex and the magnetic gradients of these active regions and their daily variations is investigated in the interval of the exceptionally high flare activity occurring in June 1970. New indices, characterizing the active region, were defined, e.g., the instantaneous sunspot-area density and the instantaneous sunspot-number density. These indices were determined on the basis of measurements of the surface containing all sunspots of the complex of active regions enclosed by an envelope. An attempt was made to substitute the surface in the relation for the individual indices by distance. The daily variations of these indices were again compared with the flare activity and some mutual relations were derived. (author)

  10. Prediction of solar activity from solar background magnetic field variations in cycles 21-23

    International Nuclear Information System (INIS)

    Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V.

    2014-01-01

    A comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e.g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in different layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26.

  11. Solar magnetic field studies using the 12 micron emission lines. II - Stokes profiles and vector field samples in sunspots

    Science.gov (United States)

    Hewagama, Tilak; Deming, Drake; Jennings, Donald E.; Osherovich, Vladimir; Wiedemann, Gunter; Zipoy, David; Mickey, Donald L.; Garcia, Howard

    1993-01-01

    Polarimetric observations at 12 microns of two sunpots are reported. The horizontal distribution of parameters such as magnetic field strength, inclination, azimuth, and magnetic field filling factors are presented along with information about the height dependence of the magnetic field strength. Comparisons with contemporary magnetostatic sunspot models are made. The magnetic data are used to estimate the height of 12 micron line formation. From the data, it is concluded that within a stable sunspot there are no regions that are magnetically filamentary, in the sense of containing both strong-field and field-free regions.

  12. On the statistical aspects of sunspot number time series and its association with the summer-monsoon rainfall over India

    Science.gov (United States)

    Chattopadhyay, Surajit; Chattopadhyay, Goutami

    The present paper reports studies on the association between the mean annual sunspot numbers and the summer monsoon rainfall over India. The cross correlations have been studied. After Box-Cox transformation, the time spectral analysis has been executed and it has been found that both of the time series have an important spectrum at the fifth harmonic. An artificial neural network (ANN) model has been developed on the data series averaged continuously by five years and the neural network could establish a predictor-predict and relationship between the sunspot numbers and the mean yearly summer monsoon rainfall over India.

  13. OSCILLATING LIGHT WALL ABOVE A SUNSPOT LIGHT BRIDGE

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuhong; Zhang, Jun; Jiang, Fayu [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xiang, Yongyuan, E-mail: shuhongyang@nao.cas.cn [Fuxian Solar Observatory, Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

    2015-05-10

    With the high tempo-spatial Interface Region Imaging Spectrograph 1330 Å images, we find that many bright structures are rooted in the light bridge of NOAA 12192, forming a light wall. The light wall is brighter than the surrounding areas, and the wall top is much brighter than the wall body. The New Vacuum Solar Telescope Hα and the Solar Dynamics Observatory 171 and 131 Å images are also used to study the light-wall properties. In 1330, 171, and 131 Å, the top of the wall has a higher emission, while in the Hα line, the wall-top emission is very low. The wall body corresponds to bright areas in 1330 Å and dark areas in the other lines. The top of the light wall moves upward and downward successively, performing oscillations in height. The deprojected mean height, amplitude, oscillation velocity, and the dominant period are determined to be 3.6 Mm, 0.9 Mm, 15.4 km s{sup −1}, and 3.9 minutes, respectively. We interpret the oscillations of the light wall as the leakage of p-modes from below the photosphere. The constant brightness enhancement of the wall top implies the existence of some kind of atmospheric heating, e.g., via the persistent small-scale reconnection or the magneto-acoustic waves. In another series of 1330 Å images, we find that the wall top in the upward motion phase is significantly brighter than in the downward phase. This kind of oscillation may be powered by the energy released due to intermittent impulsive magnetic reconnection.

  14. DEMINERALIZATION OF HUMAN DENTIN COMPARED WITH ENAMEL IN A PH-CYCLING APPARATUS WITH A CONSTANT COMPOSITION DURING DE-MINERALIZATION AND REMINERALIZATION PERIODS

    NARCIS (Netherlands)

    HERKSTROTER, FM; WITJES, M; ARENDS, J

    1991-01-01

    A comparison was made between the demineralization of enamel and dentine with and without abraded surfaces. This was done in a pH-cycling experiment for different demineralization/remineralization ratios - in the range from 1:1 to 1:4 - and for different fluoride additions (up to 2 ppm) in solution.

  15. Open magnetic fields and the solar cycle. Pt. 1

    International Nuclear Information System (INIS)

    Levine, R.H.

    1982-01-01

    Models of open magnetic structures on the Sun are presented for periods near solar minimum (CR 1626-1634) and near solar maximum (CR 1668-1678). Together with previous models of open magnetic structures during the declining phase (CR 1601-1611) these calculations provide clues to the relations between open structures, coronal holes, and active regions at different times of the solar cycle. Near solar minimum the close relation between active regions and open structures does not exist. It is suggested that near solar minimum the systematic emergence of new flux with the proper polarity imbalance to maintain open magnetic structures may occur primarily at very small spatial scales. Near solar maximum the role of active regions in maintaining open structures and coronal holes is strong, with large active regions emerging in the proper location and orientation to maintain open structures longer than typical active region lifetimes. Although the use of He I 10830 A spectroheliograms as a coronal hole indicator is shown to be subject to significant ambiguity, the agreement between calculated open structures and coronal holes determined from He I 10830 A spectroheliograms is very good. The rotation properties of calculated open structures near solar maximum strongly suggest two classes of features: one that rotates differentially similar to sunspots and active regions and a separate class that rotates more rigidly, as was the case for single large coronal holes during Skylab. (orig.)

  16. Prediction of solar cycle 24 using fourier series analysis

    International Nuclear Information System (INIS)

    Khalid, M.; Sultana, M.; Zaidi, F.

    2014-01-01

    Predicting the behavior of solar activity has become very significant. It is due to its influence on Earth and the surrounding environment. Apt predictions of the amplitude and timing of the next solar cycle will aid in the estimation of the several results of Space Weather. In the past, many prediction procedures have been used and have been successful to various degrees in the field of solar activity forecast. In this study, Solar cycle 24 is forecasted by the Fourier series method. Comparative analysis has been made by auto regressive integrated moving averages method. From sources, January 2008 was the minimum preceding solar cycle 24, the amplitude and shape of solar cycle 24 is approximate on monthly number of sunspots. This forecast framework approximates a mean solar cycle 24, with the maximum appearing during May 2014 (+- 8 months), with most sunspot of 98 +- 10. Solar cycle 24 will be ending in June 2020 (+- 7 months). The difference between two consecutive peak values of solar cycles (i.e. solar cycle 23 and 24 ) is 165 months(+- 6 months). (author)

  17. Sunspots and the physics of magnetic flux tubes in the sun

    International Nuclear Information System (INIS)

    Ballegooijen, A.A. van.

    1982-01-01

    This thesis refers to the sub-surface structure of the solar magnetic field. Following an introductory chapter, chapter II presents an analysis of spectroscopic observations of a sunspot at infrared wavelengths and models of the temperature stratification in the sunspot atmosphere are derived. The main subject of this thesis concerns the structure of the magnetic field deep down below the stellar surface, near the base of the convective envelope. In Chapter III the stability of toroidal flux tubes to wave-like perturbations is discussed, assuming that the tubes are neutrally buoyant. A model is proposed in which the toroidal flux tubes are neutrally buoyant and located in a stably stratified layer just below the base of the convective zone. On the basis of some simple assumptions for the temperature stratification in this storage layer the author considers in Chapter IV the properties of the vertical flux tubes in the convective zone. The adiabatic flux model cannot satisfactorily be applied to the simplified model of the storage layer, so that the problem of magnetic flux storage is reconsidered in Chapter V. A new model of the temperature stratification at the interface of convective zone and radiative interior of the sun is described. Finally, in Chapter VI, the stability of toroidal flux tubes in a differentially rotating star are discussed. It is demonstrated that for realistic values of the magnetic field strength, rotation has a strong effect on the stability of the toroidal flux tubes. (C.F.)

  18. NARROW-LINE-WIDTH UV BURSTS IN THE TRANSITION REGION ABOVE SUNSPOTS OBSERVED BY IRIS

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhenyong; Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.; Fu, Hui; Mou, Chaozhou; Xie, Haixia, E-mail: z.huang@sdu.edu.cn, E-mail: xld@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China)

    2016-10-01

    Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si iv line profiles as found in observations taken with the Interface Region Imaging Spectrograph (IRIS). Tentatively named as narrow-line-width UV bursts (NUBs), these structures are located above sunspots and comprise one or multiple compact bright cores at sub-arcsecond scales. We found six NUBs in two data sets (a raster and a sit-and-stare data set). Among these, four events are short-lived with a duration of ∼10 minutes, while two last for more than 36 minutes. All NUBs have Doppler shifts of 15–18 km s{sup −1}, while the NUB found in sit-and-stare data possesses an additional component at ∼50 km s{sup −1} found only in the C ii and Mg ii lines. Given that these events are found to play a role in the local dynamics, it is important to further investigate the physical mechanisms that generate these phenomena and their role in the mass transport in sunspots.

  19. The Frequency-dependent Damping of Slow Magnetoacoustic Waves in a Sunspot Umbral Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, S. Krishna; Jess, D. B. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN (United Kingdom); Doorsselaere, T. Van [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Verth, G. [School of Mathematics and Statistics, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH (United Kingdom); Morton, R. J. [Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Ellison Building, Newcastle upon Tyne, NE1 8ST (United Kingdom); Fedun, V. [Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, S1 3JD (United Kingdom); Erdélyi, R. [Solar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Christian, D. J., E-mail: krishna.prasad@qub.ac.uk [Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330 (United States)

    2017-09-20

    High spatial and temporal resolution images of a sunspot, obtained simultaneously in multiple optical and UV wavelengths, are employed to study the propagation and damping characteristics of slow magnetoacoustic waves up to transition region heights. Power spectra are generated from intensity oscillations in sunspot umbra, across multiple atmospheric heights, for frequencies up to a few hundred mHz. It is observed that the power spectra display a power-law dependence over the entire frequency range, with a significant enhancement around 5.5 mHz found for the chromospheric channels. The phase difference spectra reveal a cutoff frequency near 3 mHz, up to which the oscillations are evanescent, while those with higher frequencies propagate upward. The power-law index appears to increase with atmospheric height. Also, shorter damping lengths are observed for oscillations with higher frequencies suggesting frequency-dependent damping. Using the relative amplitudes of the 5.5 mHz (3 minute) oscillations, we estimate the energy flux at different heights, which seems to decay gradually from the photosphere, in agreement with recent numerical simulations. Furthermore, a comparison of power spectra across the umbral radius highlights an enhancement of high-frequency waves near the umbral center, which does not seem to be related to magnetic field inclination angle effects.

  20. Solar wind and coronal structure near sunspot minimum: Pioneer and SMM observations from 1985-1987

    International Nuclear Information System (INIS)

    Mihalov, J.D.; Barnes, A.; Hundhausen, A.J.; Smith, E.J.

    1990-01-01

    The solar wind speeds observed in the outer heliosphere (20 to 40 AU heliocentric distance, approximately) by Pioneers 10 an 11, and at a heliocentric distance of 0.7 AU by the Pioneer Venus spacecraft, reveal a complex set of changes in the years near the recent sunspot minimum, 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations made from the Solar Maximum Mission spacecraft during the same epoch show a systematic variation in coronal structure and (by implication) the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet (or with heliomagnetic latitude), and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum. The authors confirm here that this basic organization of the solar wind speed persists in the outer heliosphere with an orientation of the neutral sheet consistent with that inferred at a heliocentric distance of a few solar radii, from the coronal observations

  1. Observations of the longitudinal magnetic field in the transition region and photosphere of a sunspot

    Science.gov (United States)

    Henze, W., Jr.; Tandberg-Hanssen, E.; Hagyard, M. J.; West, E. A.; Woodgate, B. E.; Shine, R. A.; Beckers, J. M.; Bruner, M.; Hyder, C. L.; West, E. A.

    1982-01-01

    The Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission spacraft has observed for the first time the longitudinal component of the magnetic field by means of the Zeeman effect in the transition region above a sunspot. The data presented here were obtained on three days in one sunspot, have spatial resolutions of 10 arcsec and 3 arcsec, and yield maximum field strengths greater than 1000 G above the umbrae in the spot. The method of analysis, including a line-width calibration feature used during some of the observations, is described in some detail in an appendix; the line width is required for the determination of the longitudinal magnetic field from the observed circular polarization. The transition region data for one day are compared with photospheric magnetograms from the Marshall Space Flight Center. Vertical gradients of the magnetic field are compared from the two sets of data; the maximum gradients of 0.41 to 0.62 G/km occur above the umbra and agree with or are smaller than values observed previously in the photosphere and low chromosphere.

  2. Sunspots and the physics of magnetic flux tubes. II. Aerodynamic drag

    International Nuclear Information System (INIS)

    Parker, E.N.

    1979-01-01

    The aerodynamic drag on a slender flux tube stretched vertically across a convective cell may push the flux tube into the updrafts or into the downdrafts, depending on the density stratification of the convecting fluid and the asymmetry of the fluid motions. The drag is approximately proportional to the local kinetic energy density, so the density stratification weights the drag in favor of the upper layers where the density is low, tending to push the vertical tube into the downdrafts. If, however, the horizontal motions in the convective cell are concentrated toward the bottom of the cell, they may dominate over the upper layers, pushing the tube into the updrafts. In the simple, idealized circumstance of a vertical tube extending across a fluid of uniform density in a convective cell that is symmetric about its midplane, the net aerodynamic drag vanishes in lowest order. The higher order contributions, including the deflection of the tube, then provide a nonvanishing force pushing the tube into a stable equilibrium midway between the updraft and the downdraft.It is pointed out that in the strongly stratified convective zone of the Sun, a downdraft herds flux tubes together into a cluster, while an updraft disperses them. To account for the observed strong cohesion of the cluster of flux tubes that make up a sunspot, we propose a downdraft of the order 2 km s - 1 through the cluster of seprate tubes beneath the sunspot

  3. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22.

    Science.gov (United States)

    Silva, H G; Lopes, I

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  4. Semi-annual Sq-variation in solar activity cycle

    Science.gov (United States)

    Pogrebnoy, V.; Malosiev, T.

    The peculiarities of semi-annual variation in solar activity cycle have been studied. The data from observatories having long observational series and located in different latitude zones were used. The following observatories were selected: Huancayo (magnetic equator), from 1922 to 1959; Apia (low latitudes), from 1912 to 1961; Moscow (middle latitudes), from 1947 to 1965. Based on the hourly values of H-components, the average monthly diurnal amplitudes (a difference between midday and midnight values), according to five international quiet days, were computed. Obtained results were compared with R (relative sunspot numbers) in the ranges of 0-30R, 40-100R, and 140-190R. It was shown, that the amplitude of semi-annual variation increases with R, from minimum to maximum values, on average by 45%. At equatorial Huancayo observatory, the semi-annual Sq(H)-variation appears especially clearly: its maximums take place at periods of equinoxes (March-April, September-October), and minimums -- at periods of solstices (June-July, December-January). At low (Apia observatory) and middle (Moscow observatory) latitudes, the character of semi-annual variation is somewhat different: it appears during the periods of equinoxes, but considerably less than at equator. Besides, with the growth of R, semi-annual variation appears against a background of annual variation, in the form of second peaks (maximum in June). At observatories located in low and middle latitudes, second peaks become more appreciable with an increase of R (March-April and September-October). During the periods of low solar activity, they are insignificant. This work has been carried out with the support from International Scientific and Technology Center (Project #KR-214).

  5. Effect of solar flare ans sunspot numbers on the intensity of 5577A line in the night airglow

    International Nuclear Information System (INIS)

    Kundu, N.; Ghosh, S.N.

    1981-01-01

    The effects of solar flare and sunspot number on the intensity of 5577 A line emission are presented. The time lag between the occurrence of a flare and the enhancement of 5577 A line intensity is determined by observing the intensity of the line on three successive nights- the night preceding the flare and the two nights following it. The velocity of the solar corpuscles is then calculated. The value obtained at Allahabad (2400 Km/sec) is in agreement with the De Jager's prediction for explosive flare. Day-to-day analyses of the observations taken at Allahabad exhibit high correlation of the intensity of 5577 A line emission with sunspot number. Also, correlation is found for the intensity of 5577 A with the change in sunspot number (DELTA R) from the day preceding the night of observation to the day following it. The intensity appears to vary with the magnetic field produced by the sunspot and not with the spot area. (author)

  6. Values of Kp Indices, Ap Indices, Cp Indices, C9 Indices, Sunspot Number, and 10.7 cm Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data file consists of Kp indices, Ap indices, Cp indices, C9 indices, sunspot number, and 10.7 cm flux. The most often requested parameter of this file are the...

  7. Babcock Redux: An Amendment of Babcock's Schematic of the Sun's Magnetic Cycle

    Science.gov (United States)

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.

    2017-08-01

    We amend Babcock's original scenario for the global dynamo process that sustains the Sun's 22-year magnetic cycle. The amended scenario fits post-Babcock observed features of the magnetic activity cycle and convection zone, and is based on ideas of Spruit & Roberts (1983, Nature, 304, 401) about magnetic flux tubes in the convection zone. A sequence of four schematic cartoons lays out the proposed evolution of the global configuration of the magnetic field above, in, and at the bottom of the convection zone through sunspot Cycle 23 and into Cycle 24. Three key elements of the amended scenario are: (1) as the net following-polarity magnetic field from the sunspot-region Ω-loop fields of an ongoing sunspot cycle is swept poleward to cancel and replace the opposite-polarity polar-cap field from the previous sunspot cycle, it remains connected to the ongoing sunspot cycle's toroidal source-field band at the bottom of the convection zone; (2) topological pumping by the convection zone's free convection keeps the horizontal extent of the poleward-migrating following-polarity field pushed to the bottom, forcing it to gradually cancel and replace old horizontal field below it that connects the ongoing-cycle source-field band to the previous-cycle polar-cap field; (3) in each polar hemisphere, by continually shearing the poloidal component of the settling new horizontal field, the latitudinal differential rotation low in the convection zone generates the next-cycle source-field band poleward of the ongoing-cycle band. The amended scenario is a more-plausible version of Babcock's scenario, and its viability can be explored by appropriate kinematic flux-transport solar-dynamo simulations. A paper giving a full description of our dynamo scenario is posted on arXiv (http://arxiv.org/abs/1606.05371).This work was funded by the Heliophysics Division of NASA's Science Mission Directorate through the Living With a Star Targeted Research and Technology Program and the Hinode

  8. Periodic analysis of solar activity and its link with the Arctic oscillation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Weizheng; Li, Chun; Du, Ling; Huang, Fei [Ocean University of China, 14-1' -601, 2117 Jinshui Road, Qingdao 266100 (China); Li, Yanfang, E-mail: quweizhe@ouc.edu.cn [Yantai Institute of Coastal Zone Research Chinese Academy of Sciences (China)

    2014-12-01

    Based on spectrum analysis, we provide the arithmetic expressions of the quasi 11 yr cycle, 110 yr century cycle of relative sunspot numbers, and quasi 22 yr cycle of solar magnetic field polarity. Based on a comparative analysis of the monthly average geopotential height, geopotential height anomaly, and temperature anomaly of the northern hemisphere at locations with an air pressure of 500 HPa during the positive and negative phases of AO (Arctic Oscillation), one can see that the abnormal warming period in the Arctic region corresponds to the negative phase of AO, while the anomalous cold period corresponds to its positive phase. This shows that the abnormal change in the Arctic region is an important factor in determining the anomalies of AO. In accordance with the analysis performed using the successive filtering method, one can see that the AO phenomenon occurring in January shows a clear quasi 88 yr century cycle and quasi 22 yr decadal cycle, which are closely related to solar activities. The results of our comparative analysis show that there is a close inverse relationship between the solar activities (especially the solar magnetic field index changes) and the changes in the 22 yr cycle of the AO occurring in January, and that the two trends are basically opposite of each other. That is to say, in most cases after the solar magnetic index MI rises from the lowest value, the solar magnetic field turns from north to south, and the high-energy particle flow entering the Earth's magnetosphere increases to heat the polar atmosphere, thus causing the AO to drop from the highest value; after the solar magnetic index MI drops from the highest value, the solar magnetic field turns from south to north, and the solar high-energy particle flow passes through the top of the Earth's magnetosphere rather than entering it to heat the polar atmosphere. Thus the polar temperature drops, causing the AO to rise from the lowest value. In summary, the variance

  9. Vector magnetic fields in sunspots. I - Stokes profile analysis using the Marshall Space Flight Center magnetograph

    Science.gov (United States)

    Balasubramaniam, K. S.; West, E. A.

    1991-01-01

    The Marshall Space Flight Center (MSFC) vector magnetograph is a tunable filter magnetograph with a bandpass of 125 mA. Results are presented of the inversion of Stokes polarization profiles observed with the MSFC vector magnetograph centered on a sunspot to recover the vector magnetic field parameters and thermodynamic parameters of the spectral line forming region using the Fe I 5250.2 A spectral line using a nonlinear least-squares fitting technique. As a preliminary investigation, it is also shown that the recovered thermodynamic parameters could be better understood if the fitted parameters like Doppler width, opacity ratio, and damping constant were broken down into more basic quantities like temperature, microturbulent velocity, or density parameter.

  10. THE MYSTERIOUS CASE OF THE SOLAR ARGON ABUNDANCE NEAR SUNSPOTS IN FLARES

    International Nuclear Information System (INIS)

    Doschek, G. A.; Warren, H. P.

    2016-01-01

    Recently we discussed an enhancement of the abundance of Ar xiv relative to Ca xiv near a sunspot during a flare, observed in spectra recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The observed Ar xiv/Ca xiv ratio yields an argon/calcium abundance ratio seven times greater than expected from the photospheric abundance. Such a large abundance anomaly is unprecedented in the solar atmosphere. We interpreted this result as being due to an inverse first ionization potential (FIP) effect. In the published work, two lines of Ar xiv were observed, and one line was tentatively identified as an Ar xi line. In this paper, we report observing a similar enhancement in a full-CCD EIS flare spectrum in 13 argon lines that lie within the EIS wavelength ranges. The observed lines include two Ar xi lines, four Ar xiii lines, six Ar xiv lines, and one Ar xv line. The enhancement is far less than reported in Doschek et al. but exhibits similar morphology. The argon abundance is close to a photospheric abundance in the enhanced area, and the abundance could be photospheric. This enhancement occurs in association with a sunspot in a small area only a few arcseconds (1″ = about 700 km) in size. There is no enhancement effect observed in the normally high-FIP sulfur and oxygen line ratios relative to lines of low-FIP elements available to EIS. Calculations of path lengths in the strongest enhanced area in Doschek et al. indicate a depletion of low-FIP elements.

  11. NUMERICAL SIMULATIONS OF CONVERSION TO ALFVÉN WAVES IN SUNSPOTS

    International Nuclear Information System (INIS)

    Khomenko, E.; Cally, P. S.

    2012-01-01

    We study the conversion of fast magnetoacoustic waves to Alfvén waves by means of 2.5D numerical simulations in a sunspot-like magnetic configuration. A fast, essentially acoustic, wave of a given frequency and wave number is generated below the surface and propagates upward through the Alfvén/acoustic equipartition layer where it splits into upgoing slow (acoustic) and fast (magnetic) waves. The fast wave quickly reflects off the steep Alfvén speed gradient, but around and above this reflection height it partially converts to Alfvén waves, depending on the local relative inclinations of the background magnetic field and the wavevector. To measure the efficiency of this conversion to Alfvén waves we calculate acoustic and magnetic energy fluxes. The particular amplitude and phase relations between the magnetic field and velocity oscillations help us to demonstrate that the waves produced are indeed Alfvén waves. We find that the conversion to Alfvén waves is particularly important for strongly inclined fields like those existing in sunspot penumbrae. Equally important is the magnetic field orientation with respect to the vertical plane of wave propagation, which we refer to as 'field azimuth'. For a field azimuth less than 90° the generated Alfvén waves continue upward, but above 90° downgoing Alfvén waves are preferentially produced. This yields negative Alfvén energy flux for azimuths between 90° and 180°. Alfvén energy fluxes may be comparable to or exceed acoustic fluxes, depending upon geometry, though computational exigencies limit their magnitude in our simulations.

  12. SIMULATION STUDY OF HEMISPHERIC PHASE-ASYMMETRY IN THE SOLAR CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Shukuya, D.; Kusano, K., E-mail: kusano@nagoya-u.jp [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 4648601 (Japan)

    2017-01-20

    Observations of the Sun suggest that solar activities systematically create north–south hemispheric asymmetries. For instance, the hemisphere in which sunspot activity is more active tends to switch after the early half of each solar cycle. Svalgaard and Kamide recently pointed out that the time gaps of polar field reversal between the northern and southern hemispheres are simply consequences of the asymmetry of sunspot activity. However, the mechanism underlying the asymmetric feature in solar cycle activity is not yet well understood. In this paper, in order to explain the cause of the asymmetry from the theoretical point of view, we investigate the relationship between the dipole- and quadrupole-type components of the magnetic field in the solar cycle using the mean-field theory based on the flux transport dynamo model. As a result, we found that there are two different attractors of the solar cycle, in which either the north or the south polar field is first reversed, and that the flux transport dynamo model explains well the phase-asymmetry of sunspot activity and the polar field reversal without any ad hoc source of asymmetry.

  13. Signature of a possible relationship between the maximum CME speed index and the critical frequencies of the F1 and F2 ionospheric layers: Data analysis for a mid-latitude ionospheric station during the solar cycles 23 and 24

    Science.gov (United States)

    Kilcik, Ali; Ozguc, Atila; Yiǧit, Erdal; Yurchyshyn, Vasyl; Donmez, Burcin

    2018-06-01

    We analyze temporal variations of two solar indices, the monthly mean Maximum CME Speed Index (MCMESI) and the International Sunspot Number (ISSN) as well as the monthly median ionospheric critical frequencies (foF1, and foF2) for the time period of 1996-2013, which covers the entire solar cycle 23 and the ascending branch of the cycle 24. We found that the maximum of foF1 and foF2 occurred respectively during the first and second maximum of the ISSN solar activity index in the solar cycle 23. We compared these data sets by using the cross-correlation and hysteresis analysis and found that both foF1 and foF2 show higher correlation with ISSN than the MCMESI during the investigated time period, but when significance levels are considered correlation coefficients between the same indices become comparable. Cross-correlation analysis showed that the agreement between these data sets (solar indices and ionospheric critical frequencies) is better pronounced during the ascending phases of solar cycles, while they display significant deviations during the descending phase. We conclude that there exists a signature of a possible relationship between MCMESI and foF1 and foF2, which means that MCMESI could be used as a possible indicator of solar and geomagnetic activity, even though other investigations are needed.

  14. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  15. Evaluation of different fuel cycle options in accordance with nuclear energy production planning in Turkey. Final report for the period 15 December 1995 - 1 July 1998

    International Nuclear Information System (INIS)

    Uzmen, R.

    1998-08-01

    For two decades, Turkey has been considering the implementation of a nuclear power program in order to ensure a secure and ecologically non-pollutant electricity supply, and a site was selected at Akkuyu on the Mediterranean coaast. The energy gap predicted in recent projections could be partly filled by nuclear power. The present plan of the Ministry of Energy schedules the commissioning of at least 2,000 MWe nuclear capacity by 2010. In this report, firstly reference reactors were selected and then requirements of fuel material and services for these reactors were discussed according to Turkey's energy generation scenarios. For this study the reactor selection criteria are: 1) Provenness by operation, 2) Plant power rating, 3) Generic safety, and 4) Licensability. In this study, two types of reactors (PWR and PHWR) that meet the safety and selection criteria were taken into consideration. For Turkey's case, fuel demand and options were discussed according to these reactor types. Status and trends in the world in nuclear electricity generation, nuclear power projection, uranium production, uranium supply and demand relationships, future trends in supply and demand and supply projection were investigated. World uranium market, uranium prices analysis, refining and conversion, enrichment, fuel fabrication, fuel burnup and back-end options were thoroughly discussed. The economics of the nuclear fuel cycle was investigated, fuel costs for PWR and PHWR were calculated. As a result of the obtained reference data a table was prepared for fuel material and services requirements according to reactor type and size. The need for nuclear power in Turkey was discussed in detail, focussing on primary resources in Turkey, demand predictions, usage ratios of domestic and imported resources. Electricity generation scenarios for Turkey were discussed and final conclusions were drawn for Turkey's case. Comparisons of the domestic and imported resources in accordance with the

  16. Emergence of Magnetic Flux Generated in a Solar Convective Dynamo. I. The Formation of Sunspots and Active Regions, and The Origin of Their Asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Feng; Rempel, Matthias; Fan, Yuhong, E-mail: chenfeng@ucar.edu [High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO, 80307 (United States)

    2017-09-10

    We present a realistic numerical model of sunspot and active region formation based on the emergence of flux bundles generated in a solar convective dynamo. To this end, we use the magnetic and velocity fields in a horizontal layer near the top boundary of the solar convective dynamo simulation to drive realistic radiative-magnetohydrodynamic simulations of the uppermost layers of the convection zone. The main results are as follows. (1) The emerging flux bundles rise with the mean speed of convective upflows and fragment into small-scale magnetic elements that further rise to the photosphere, where bipolar sunspot pairs are formed through the coalescence of the small-scale magnetic elements. (2) Filamentary penumbral structures form when the sunspot is still growing through ongoing flux emergence. In contrast to the classical Evershed effect, the inflow seems to prevail over the outflow in a large part of the penumbra. (3) A well-formed sunspot is a mostly monolithic magnetic structure that is anchored in a persistent deep-seated downdraft lane. The flow field outside the spot shows a giant vortex ring that comprises an inflow below 15 Mm depth and an outflow above 15 Mm depth. (4) The sunspots successfully reproduce the fundamental properties of the observed solar active regions, including the more coherent leading spots with a stronger field strength, and the correct tilts of bipolar sunspot pairs. These asymmetries can be linked to the intrinsic asymmetries in the magnetic and flow fields adapted from the convective dynamo simulation.

  17. CHROMOSPHERIC MASS MOTIONS AND INTRINSIC SUNSPOT ROTATIONS FOR NOAA ACTIVE REGIONS 10484, 10486, AND 10488 USING ISOON DATA

    International Nuclear Information System (INIS)

    Hardersen, Paul S.; Balasubramaniam, K. S.; Shkolyar, Svetlana

    2013-01-01

    This work utilizes Improved Solar Observing Optical Network continuum (630.2 nm) and Hα (656.2 nm) data to: (1) detect and measure intrinsic sunspot rotations occurring in the photosphere and chromosphere, (2) identify and measure chromospheric filament mass motions, and (3) assess any large-scale photospheric and chromospheric mass couplings. Significant results from 2003 October 27-29, using the techniques of Brown et al., indicate significant counter-rotation between the two large sunspots in NOAA AR 10486 on October 29, as well as discrete filament mass motions in NOAA AR 10484 on October 27 that appear to be associated with at least one C-class solar flare

  18. Bipolar mood cycles and lunar tidal cycles.

    Science.gov (United States)

    Wehr, T A

    2018-04-01

    In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon's semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies ('supermoons'). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles' being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon's semi-diurnal gravimetric tides might have driven the patients' bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker's phase-relationship to sleep in a manner that is known to cause switches from depression to mania.

  19. Successive X-class Flares and Coronal Mass Ejections Driven by Shearing Motion and Sunspot Rotation in Active Region NOAA 12673

    Science.gov (United States)

    Yan, X. L.; Wang, J. C.; Pan, G. M.; Kong, D. F.; Xue, Z. K.; Yang, L. H.; Li, Q. L.; Feng, X. S.

    2018-03-01

    We present a clear case study on the occurrence of two successive X-class flares, including a decade-class flare (X9.3) and two coronal mass ejections (CMEs) triggered by shearing motion and sunspot rotation in active region NOAA 12673 on 2017 September 6. A shearing motion between the main sunspots with opposite polarities began on September 5 and lasted even after the second X-class flare on September 6. Moreover, the main sunspot with negative polarity rotated around its umbral center, and another main sunspot with positive polarity also exhibited a slow rotation. The sunspot with negative polarity at the northwest of the active region also began to rotate counterclockwise before the onset of the first X-class flare, which is related to the formation of the second S-shaped structure. The successive formation and eruption of two S-shaped structures were closely related to the counterclockwise rotation of the three sunspots. The existence of a flux rope is found prior to the onset of two flares by using nonlinear force-free field extrapolation based on the vector magnetograms observed by Solar Dynamics Observatory/Helioseismic and Magnetic Image. The first flux rope corresponds to the first S-shaped structures mentioned above. The second S-shaped structure was formed after the eruption of the first flux rope. These results suggest that a shearing motion and sunspot rotation play an important role in the buildup of the free energy and the formation of flux ropes in the corona that produces solar flares and CMEs.

  20. DETECTION OF SUPERSONIC DOWNFLOWS AND ASSOCIATED HEATING EVENTS IN THE TRANSITION REGION ABOVE SUNSPOTS

    Energy Technology Data Exchange (ETDEWEB)

    Kleint, L.; Martínez-Sykora, J. [Bay Area Environmental Research Institute, 625 2nd Street, Ste. 209, Petaluma, CA (United States); Antolin, P. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Tian, H.; Testa, P.; Reeves, K. K.; McKillop, S.; Saar, S.; Golub, L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Judge, P. [High Altitude Observatory/NCAR, P.O. Box 3000, Boulder, CO 80307 (United States); De Pontieu, B.; Wuelser, J. P.; Boerner, P.; Hurlburt, N.; Lemen, J.; Tarbell, T. D.; Title, A. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover St., Org. ADBS, Bldg. 252, Palo Alto, CA 94304 (United States); Carlsson, M.; Hansteen, V. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Jaeggli, S., E-mail: lucia.kleint@fhnw.ch [Department of Physics, Montana State University, Bozeman, P.O. Box 173840, Bozeman, MT 59717 (United States); and others

    2014-07-10

    Interface Region Imaging Spectrograph data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.''33. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km s{sup –1} and weaker, slightly slower upflows in the spectral lines Mg II h and k, C II 1336, Si IV 1394 Å, and 1403 Å, that are correlated with brightenings in the slitjaw images (SJIs). The bursty behavior lasts throughout the 2 hr observation, with average burst durations of about 20 s. The locations of these short-lived events appear to be the umbral and penumbral footpoints of EUV loops. Fast apparent downflows are observed along these loops in the SJIs and in the Atmospheric Imaging Assembly, suggesting that the loops are thermally unstable. We interpret the observations as cool material falling from coronal heights, and especially coronal rain produced along the thermally unstable loops, which leads to an increase of intensity at the loop footpoints, probably indicating an increase of density and temperature in the TR. The rain speeds are on the higher end of previously reported speeds for this phenomenon, and possibly higher than the free-fall velocity along the loops. On other observing days, similar bright dots are sometimes aligned into ribbons, resembling small flare ribbons. These observations provide a first insight into small-scale heating events in sunspots in the TR.

  1. EVIDENCE FOR A TRANSITION REGION RESPONSE TO PENUMBRAL MICROJETS IN SUNSPOTS

    International Nuclear Information System (INIS)

    Vissers, G. J. M.; Rouppe van der Voort, L. H. M.; Carlsson, M.

    2015-01-01

    Penumbral microjets (PMJs) are short-lived, fine-structured, and bright jets that are generally observed in chromospheric imaging of the penumbra of sunspots. Here we investigate their potential transition region signature by combining observations with the Swedish 1-m Solar Telescope in the Ca ii H and Ca ii 8542 Å lines with ultraviolet imaging and spectroscopy obtained with the Interface Region Imaging Spectrograph (IRIS), which includes the C ii 1334/1335 Å, Si iv 1394/1403 Å, and Mg ii h and k 2803/2796 Å lines. We find a clear corresponding signal in the IRIS Mg ii k, C ii, and Si iv slit-jaw images, typically offset spatially from the Ca ii signature in the direction along the jets: from base to top, the PMJs are predominantly visible in Ca ii, Mg ii k, and C ii/Si iv, suggesting progressive heating to transition region temperatures along the jet extent. Hence, these results support the suggestion from earlier studies that PMJs may heat to transition region temperatures

  2. Fan-shaped jets above the light bridge of a sunspot driven by reconnection

    Science.gov (United States)

    Robustini, Carolina; Leenaarts, Jorrit; de la Cruz Rodriguez, Jaime; Rouppe van der Voort, Luc

    2016-05-01

    We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα line. We study the origin, dynamics, and thermal properties of the jets using high-resolution imaging spectroscopy in Hα from the Swedish 1m Solar Telescope and data from the Solar Dynamics Observatory and Hinode. The Hα jets have lengths of 7-38 Mm, are impulsively accelerated to a speed of ~100 km s-1 close to photospheric footpoints in the LB, and exhibit a constant deceleration consistent with solar effective gravity. They are predominantly launched from one edge of the light bridge, and their footpoints appear bright in the Hα wings. Atmospheric Imaging Assembly data indicates elongated brightenings that are nearly co-spatial with the Hα jets. We interpret them as jets of transition region temperatures. The magnetic field in the light bridge has a strength of 0.8-2 kG and it is nearly horizontal. All jet properties are consistent with magnetic reconnection as the driver. Movies associated to Figs. 1 and 2 are available in electronic form at http://www.aanda.org

  3. Simultaneous Observations of p-mode Light Walls and Magnetic Reconnection Ejections above Sunspot Light Bridges

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yijun; Zhang, Jun; Li, Ting; Yang, Shuhong; Li, Xiaohong, E-mail: yijunhou@nao.cas.cn, E-mail: zjun@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2017-10-10

    Recent high-resolution observations from the Interface Region Imaging Spectrograph reveal bright wall-shaped structures in active regions (ARs), especially above sunspot light bridges. Their most prominent feature is the bright oscillating front in the 1400/1330 Å channel. These structures are named light walls and are often interpreted to be driven by p-mode waves. Above the light bridge of AR 12222 on 2014 December 06, we observed intermittent ejections superimposed on an oscillating light wall in the 1400 Å passband. At the base location of each ejection, the emission enhancement was detected in the Solar Dynamics Observatory 1600 Å channel. Thus, we suggest that in wall bases (light bridges), in addition to the leaked p-mode waves consistently driving the oscillating light wall, magnetic reconnection could happen intermittently at some locations and eject the heated plasma upward. Similarly, in the second event occurring in AR 12371 on 2015 June 16, a jet was simultaneously detected in addition to the light wall with a wave-shaped bright front above the light bridge. At the footpoint of this jet, lasting brightening was observed, implying magnetic reconnection at the base. We propose that in these events, two mechanisms, p-mode waves and magnetic reconnection, simultaneously play roles in the light bridge, and lead to the distinct kinetic features of the light walls and the ejection-like activities, respectively. To illustrate the two mechanisms and their resulting activities above light bridges, in this study we present a cartoon model.

  4. On the structure of a magnetic field and its evolution in the vicinity of sunspots

    International Nuclear Information System (INIS)

    Gopasyuk, S.I.; Kartashova, L.G.

    1981-01-01

    The structure of magnetic field and its evolution around single large sunspots has been studied. For this purpose observational data of the longitudinal magnetic field on the photospheric level and hsub(α) filtergrams for 18 active regions have been used. It is shown that there are characteristic directions corresponding to the transition of the spot field without sign change into an extended region of the same polarity and coinciding with extended (100000-300000 km) systems of filamentary feature chains of the fine chromospheric structure in active region. The horizontal magnetic f+eld component of the spot (systems of filamentary feature chains of the fine chromospheric structure) disappears on an extended region of chromospheric surface in the direction, where the satellite field (the field of opposite polarity) appears near its boundary. On the other hand, when satellite field disappears at some direction from the spot the transversal magnetic field appears on the extended surface region of the chromosphere keeping the same direction. One of the possible causes of disappearance of the transversal magnetic field on an extended region in the chromosphere might be the reconnection of magnetic lines of force [ru

  5. Impact of Spanish electricity mix, over the period 2008–2030, on the Life Cycle energy consumption and GHG emissions of Electric, Hybrid Diesel-Electric, Fuel Cell Hybrid and Diesel Bus of the Madrid Transportation System

    International Nuclear Information System (INIS)

    García Sánchez, Juan Antonio; López Martínez, José María; Lumbreras Martín, Julio; Flores Holgado, María Nuria; Aguilar Morales, Hansel

    2013-01-01

    Highlights: • We assess the performance of 4 buses that run on different alternative fuel types and technologies. • The buses assessed are Fuel Cell-Hybrid Bus, Hybrid Diesel-Electric Bus, Battery Electric Bus, and a Diesel Bus. • We examine the environmental impact caused by the Life Cycle of each vehicle technology, fossil fuel and energy carrier. • Life Cycle of Battery Electric Bus shows that it has a big potential of improvement in terms of environmental impact. - Abstract: In spite of the advanced research in automotive technology, and the improvement of fuels, the road transport sector continues to be an environmental concern, since the increase in transport demand is offsetting the effects of these technological improvements. Therefore, this poses the following question: what combination of technology and fuel is more efficient in terms of energy consumption and green house gas (GHG) emissions? To fully address this question it is necessary to carry out a Life Cycle Assessment (LCA). This paper presents a global LCA of 4 buses that run on the following fuel types and technologies: (1) Fuel Cell- Hybrid Bus, (2) Hybrid Diesel-Electric Bus (series configuration), (3) Battery Electric Bus and (4) Combustion Ignition Engine Bus. The impact categories assessed are: primary energy consumption, fossil energy and GHG emissions. Among the principal results, we can conclude that the Global LCA of buses (3) and (1) (which are the more sensitive pathways to the electricity mix variation) have for the 2008–2030 period a room for improvement of 25.62% and 28.16% in terms of efficiency of fossil energy consumption and a potential GHG emission reduction of 28.70% and 30.88% respectively

  6. Worldwide variation in atmospheric noise intensities with sunspot number: an in-depth look at the 20 to 24 hour seasonal time block

    International Nuclear Information System (INIS)

    Joglekar, P.J.; Sathiamurthy, T.S.

    1975-01-01

    Comparisons of the variation of atmospheric radio noise intensities for 20 to 24 hr to sunspot numbers have been completed. Statistical dependence between the noise intensities and sunspot numbers was found for different seasons at a number of frequencies for many locations in the global network of ARN-2 noise recorders. The noise intensities generally tended to decrease with sunspot number in the range from 50 kHz to 5 MHz, which is presumed to be due to increases in residual ionospheric absorption during nighttime. At frequencies greater than 5 MHz, noise intensities increased with sunspot number in many cases, which would be expected from our present knowledge of ionospheric behavior in the HF range. By convention, CCIR treats year-to-year variation in the noise intensities as random and includes them in the prediction uncertainty sigma /sub Fam/ (for which one value is given at a frequency for a seasonal time block for all locations) in system performance evaluation. An error analysis on a global basis shows that a large portion of the year-to-year variability is due to sunspot variation. This suggests the possibility of improved noise estimates. (auth)

  7. A SOLAR FLARE DISTURBING A LIGHT WALL ABOVE A SUNSPOT LIGHT BRIDGE

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yijun; Zhang, Jun; Li, Ting; Yang, Shuhong; Li, Leping; Li, Xiaohong, E-mail: yijunhou@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2016-10-01

    With the high-resolution data from the Interface Region Imaging Spectrograph , we detect a light wall above a sunspot light bridge in the NOAA active region (AR) 12403. In the 1330 Å slit-jaw images, the light wall is brighter than the ambient areas while the wall top and base are much brighter than the wall body, and it keeps oscillating above the light bridge. A C8.0 flare caused by a filament activation occurred in this AR with the peak at 02:52 UT on 2015 August 28, and the flare’s one ribbon overlapped the light bridge, which was the observational base of the light wall. Consequently, the oscillation of the light wall was evidently disturbed. The mean projective oscillation amplitude of the light wall increased from 0.5 to 1.6 Mm before the flare and decreased to 0.6 Mm after the flare. We suggest that the light wall shares a group of magnetic field lines with the flare loops, which undergo a magnetic reconnection process, and they constitute a coupled system. When the magnetic field lines are pushed upward at the pre-flare stage, the light wall turns to the vertical direction, resulting in the increase of the light wall’s projective oscillation amplitude. After the magnetic reconnection takes place, a group of new field lines with smaller scales are formed underneath the reconnection site, and the light wall inclines. Thus, the projective amplitude notably decrease at the post-flare stage.

  8. A SOLAR FLARE DISTURBING A LIGHT WALL ABOVE A SUNSPOT LIGHT BRIDGE

    International Nuclear Information System (INIS)

    Hou, Yijun; Zhang, Jun; Li, Ting; Yang, Shuhong; Li, Leping; Li, Xiaohong

    2016-01-01

    With the high-resolution data from the Interface Region Imaging Spectrograph , we detect a light wall above a sunspot light bridge in the NOAA active region (AR) 12403. In the 1330 Å slit-jaw images, the light wall is brighter than the ambient areas while the wall top and base are much brighter than the wall body, and it keeps oscillating above the light bridge. A C8.0 flare caused by a filament activation occurred in this AR with the peak at 02:52 UT on 2015 August 28, and the flare’s one ribbon overlapped the light bridge, which was the observational base of the light wall. Consequently, the oscillation of the light wall was evidently disturbed. The mean projective oscillation amplitude of the light wall increased from 0.5 to 1.6 Mm before the flare and decreased to 0.6 Mm after the flare. We suggest that the light wall shares a group of magnetic field lines with the flare loops, which undergo a magnetic reconnection process, and they constitute a coupled system. When the magnetic field lines are pushed upward at the pre-flare stage, the light wall turns to the vertical direction, resulting in the increase of the light wall’s projective oscillation amplitude. After the magnetic reconnection takes place, a group of new field lines with smaller scales are formed underneath the reconnection site, and the light wall inclines. Thus, the projective amplitude notably decrease at the post-flare stage.

  9. Extending Counter-streaming Motion from an Active Region Filament to a Sunspot Light Bridge

    Science.gov (United States)

    Wang, Haimin; Liu, Rui; Li, Qin; Liu, Chang; Deng, Na; Xu, Yan; Jing, Ju; Wang, Yuming; Cao, Wenda

    2018-01-01

    We analyze high-resolution observations from the 1.6 m telescope at Big Bear Solar Observatory that cover an active region filament. Counter-streaming motions are clearly observed in the filament. The northern end of the counter-streaming motions extends to a light bridge, forming a spectacular circulation pattern around a sunspot, with clockwise motion in the blue wing and counterclockwise motion in the red wing, as observed in the Hα off-bands. The apparent speed of the flow is around 10–60 km s‑1 in the filament, decreasing to 5–20 km s‑1 in the light bridge. The most intriguing results are the magnetic structure and the counter-streaming motions in the light bridge. Similar to those in the filament, the magnetic fields show a dominant transverse component in the light bridge. However, the filament is located between opposed magnetic polarities, while the light bridge is between strong fields of the same polarity. We analyze the power of oscillations with the image sequences of constructed Dopplergrams, and find that the filament’s counter-streaming motion is due to physical mass motion along fibrils, while the light bridge’s counter-streaming motion is due to oscillation in the direction along the line-of-sight. The oscillation power peaks around 4 minutes. However, the section of the light bridge next to the filament also contains a component of the extension of the filament in combination with the oscillation, indicating that some strands of the filament are extended to and rooted in that part of the light bridge.

  10. Entrepreneurship and the business cycle

    NARCIS (Netherlands)

    Koellinger, Philipp D.; Thurik, A. Roy

    2012-01-01

    We find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972 to 2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment cycle. We

  11. Seasonal, Diurnal, and Solar-Cycle Variations of Electron Density at Two West Africa Equatorial Ionization Anomaly Stations

    Directory of Open Access Journals (Sweden)

    Frédéric Ouattara

    2012-01-01

    Full Text Available We analyse the variability of foF2 at two West Africa equatorial ionization anomaly stations (Ouagadougou and Dakar during three solar cycles (from cycle 20 to cycle 22, that is, from 1966 to 1998 for Ouagadougou and from 1971 to 1997 for Dakar. We examine the effect of the changing levels of solar extreme ultraviolet radiation with sunspot number. The study shows high correlation between foF2 and sunspot number (Rz. The correlation coefficient decreases from cycle 20 to cycle 21 at both stations. From cycle 21 to cycle 22 it decreases at Ouagadougou station and increases at Dakar station. The best correlation coefficient, 0.990, is obtained for Dakar station during solar cycle 22. The seasonal variation displays equinoctial peaks that are asymmetric between March and September. The percentage deviations of monthly average data from one solar cycle to another display variability with respect to solar cycle phase and show solar ultraviolet radiation variability with solar cycle phase. The diurnal variation shows a noon bite out with a predominant late-afternoon peak except during the maximum phase of the solar cycle. The diurnal Ouagadougou station foF2 data do not show a significant difference between the increasing and decreasing cycle phases, while Dakar station data do show it, particularly for cycle 21. The percentage deviations of diurnal variations from solar-minimum conditions show more ionosphere during solar cycle 21 at both stations for all three of the other phases of the solar cycle. There is no significant variability of ionosphere during increasing and decreasing solar cycle phases at Ouagadougou station, but at Dakar station there is a significant variability of ionosphere during these two solar-cycle phases.

  12. Determination of the Alfvén Speed and Plasma-beta Using the Seismology of Sunspot Umbra

    Energy Technology Data Exchange (ETDEWEB)

    Cho, I.-H.; Moon, Y.-J.; Nakariakov, V. M.; Park, J.; Choi, S. [Department of Astronomy and Space Science, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Cho, K.-S.; Bong, S.-C.; Baek, J.-H.; Kim, Y.-H.; Lee, J., E-mail: ihjo@khu.ac.kr [Space Science Division, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2017-03-01

    For 478 centrally located sunspots observed in the optical continuum with Solar Dynamics Observatory /Helioseismic Magnetic Imager, we perform seismological diagnostics of the physical parameters of umbral photospheres. The new technique is based on the theory of slow magnetoacoustic waves in a non-isothermally stratified photosphere with a uniform vertical magnetic field. We construct a map of the weighted frequency of three-minute oscillations inside the umbra and use it for the estimation of the Alfvén speed, plasma-beta, and mass density within the umbra. We find the umbral mean Alfvén speed ranges between 10.5 and 7.5 km s{sup −1} and is negatively correlated with magnetic field strength. The umbral mean plasma-beta is found to range approximately between 0.65 and 1.15 and does not vary significantly from pores to mature sunspots. The mean density ranges between (1–6) × 10{sup −4} kg m{sup −3} and shows a strong positive correlation with magnetic field strength.

  13. Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles

    Directory of Open Access Journals (Sweden)

    Sara F. Martin

    2018-05-01

    Full Text Available Observational evidence for the origin of active region magnetic fields has been sought from published information on extended solar cycles, statistical distributions of active regions and ephemeral regions, helioseismology results, positional relationships to supergranules, and fine-scale magnetic structure of active regions and their sunspots during their growth. Statistical distributions of areas of ephemeral and active regions blend together to reveal a single power law. The shape of the size distribution in latitude of all active regions is independent of time during the solar cycle, yielding further evidence that active regions of all sizes belong to the same population. Elementary bipoles, identified also by other names, appear to be the building blocks of active regions; sunspots form from elementary bipoles and are therefore deduced to develop from the photosphere downward, consistent with helioseismic detection of downflows to 3–4 Mm below sunspots as well as long-observed downflows from chromospheric/coronal arch filaments into sunspots from their earliest appearance. Time-distance helioseismology has been effective in revealing flows related to sunspots to depths of 20 Mm. Ring diagram analysis shows a statistically significant preference for upflows to precede major active region emergence and downflows after flux emergence but both are often observed together or not detected. From deep-focus helioseismic techniques for seeking magnetic flux below the photosphere prior major active regions, there is evidence of acoustic travel-time perturbation signatures rising in the limited range of depths of 42–75 Mm but these have not been verified or found at more shallow depths by helioseismic holographic techniques. The development of active regions from clusters of elementary bipoles appears to be the same irrespective of how much flux an active region eventually develops. This property would be consistent with the magnetic fields of

  14. Estimate of the upper limit of amplitude of Solar Cycle No. 23

    Energy Technology Data Exchange (ETDEWEB)

    Silbergleit, V. M; Larocca, P. A [Departamento de Fisica, UBA (Argentina)

    2001-07-01

    AA* indices of values greater than 60 10{sup -9} Tesla are considered in order to characterize geomagnetic storms since the available series of these indices comprise the years from 1868 to 1998 (The longest existing interval of geomagnetic activity). By applying the precursor technique we have performed an analysis of the storm periods and the solar activity, obtaining a good correlation between the number of storms ({alpha})(characterized by the AA* indices) and the amplitudes of each solar cycle ({zeta}) and those of the next ({mu}). Using the multiple regression method applied to {alpha}=A+B{zeta} +C{mu}, the constants are calculated and the values found are: A=-33 {+-}18, B= 0.74{+-}0.13 y C= 0.56{+-}0.13. The present statistical method indicates that the current solar cycle (number 23) would have an upper limit of 202{+-}57 monthy mean sunspots. This value indicates that the solar activity would be high causing important effects on the Earth's environment. [Spanish] Se consideran los valores de los indices AA* de valor mayor que 60 10{sup -9} Tesla para caracterizar tormentas geomagneticas ya que las series disponibles de estos indices van desde 1868 hasta 1998 (el mas largo intervalo de la actividad geomagnetica existente). Aplicando la tecnica del precursor hemos realizado un analisis de los periodos de tormentas y la actividad solar obteniendo una buena correlacion entre el numero de tormentas ({alpha}) (caracterizado por los indices AA*) y las amplitudes de los ciclos solares corriente ({zeta}) y el proximo ({mu}). Usando el metodo de regresion multiple aplicado a {alpha}=A+B{zeta} +C{mu}, las consonantes resultaron: A=-33 {+-}18, B= 0.74{+-}0.13 y C= 0.56{+-}0.13. El metodo estadistico presentado indica que el ciclo actual (numero 23) tendria un pico de 202{+-} 57 manchas mensuales promedio. Este valor indica que la actividad solar seria alta produciendo importantes efectos en el medio ambiente terrestre.

  15. Normal and counter Evershed flows in the photospheric penumbra of a sunspot SPINOR 2D inversions of Hinode-SOT/SP observations

    Czech Academy of Sciences Publication Activity Database

    Siu-Tapia, A.; Lagg, A.; Solanki, S.K.; van Noort, M.; Jurčák, Jan

    2017-01-01

    Roč. 607, November (2017), A36/1-A36/17 E-ISSN 1432-0746 Institutional support: RVO:67985815 Keywords : sunspots * photosphere * magnetic fields Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  16. HEMISPHERIC HELICITY TREND FOR SOLAR CYCLE 24

    International Nuclear Information System (INIS)

    Hao Juan; Zhang Mei

    2011-01-01

    Using vector magnetograms obtained with the Spectro-polarimeter (SP) on board Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions that occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active regions of the solar cycle 24 follow the so-called hemispheric helicity rule, whereas the 30 active regions of the solar cycle 23 do not. (2) When combining all 64 active regions as one sample, they follow the hemispheric helicity sign rule as in most other observations. (3) Despite the so-far most accurate measurement of vector magnetic field given by SP/Hinode, the rule is still weak with large scatters. (4) The data show evidence of different helicity signs between strong and weak fields, confirming previous result from a large sample of ground-based observations. (5) With two example sunspots we show that the helicity parameters change sign from the inner umbra to the outer penumbra, where the sign of penumbra agrees with the sign of the active region as a whole. From these results, we speculate that both the Σ-effect (turbulent convection) and the dynamo have contributed in the generation of helicity, whereas in both cases turbulence in the convection zone has played a significant role.

  17. The Heliosphere through the Solar Activity Cycle

    CERN Document Server

    Balogh, André; Suess, Steven T

    2008-01-01

    Understanding how the Sun changes though its 11-year sunspot cycle and how these changes affect the vast space around the Sun – the heliosphere – has been one of the principal objectives of space research since the advent of the space age. This book presents the evolution of the heliosphere through an entire solar activity cycle. The last solar cycle (cycle 23) has been the best observed from both the Earth and from a fleet of spacecraft. Of these, the joint ESA-NASA Ulysses probe has provided continuous observations of the state of the heliosphere since 1990 from a unique vantage point, that of a nearly polar orbit around the Sun. Ulysses’ results affect our understanding of the heliosphere from the interior of the Sun to the interstellar medium - beyond the outer boundary of the heliosphere. Written by scientists closely associated with the Ulysses mission, the book describes and explains the many different aspects of changes in the heliosphere in response to solar activity. In particular, the authors...

  18. ON THE WEAKENING OF THE POLAR MAGNETIC FIELDS DURING SOLAR CYCLE 23

    International Nuclear Information System (INIS)

    Wang, Y.-M.; Sheeley, N. R.; Robbrecht, E.

    2009-01-01

    The Sun's polar fields are currently ∼40% weaker than they were during the previous three sunspot minima. This weakening has been accompanied by a corresponding decrease in the interplanetary magnetic field (IMF) strength, by a ∼20% shrinkage in the polar coronal-hole areas, and by a reduction in the solar-wind mass flux over the poles. It has also been reflected in coronal streamer structure and the heliospheric current sheet, which only showed the expected flattening into the equatorial plane after sunspot numbers fell to unusually low values in mid-2008. From latitude-time plots of the photospheric field, it has long been apparent that the polar fields are formed through the transport of trailing-polarity flux from the sunspot latitudes to the poles. To address the question of why the polar fields are now so weak, we simulate the evolution of the photospheric field and radial IMF strength from 1965 to the present, employing a surface transport model that includes the effects of active region emergence, differential rotation, supergranular convection, and a poleward bulk flow. We find that the observed evolution can be reproduced if the amplitude of the surface meridional flow is varied by as little as 15% (between 14.5 and 17 m s -1 ), with the higher average speeds being required during the long cycles 20 and 23.

  19. Prediction of the Length of Upcoming Solar Cycles

    Science.gov (United States)

    Kakad, Bharati; Kakad, Amar; Ramesh, Durbha Sai

    2017-12-01

    The forecast of solar cycle (SC) characteristics is crucial particularly for several space-based missions. In the present study, we propose a new model for predicting the length of the SC. The model uses the information of the width of an autocorrelation function that is derived from the daily sunspot data for each SC. We tested the model on Versions 1 and 2 of the daily international sunspot number data for SCs 10 - 24. We found that the autocorrelation width Aw n of SC n during the second half of its ascending phase correlates well with the modified length that is defined as T_{cy}^{n+2} - Tan. Here T_{cy}^{n+2} and T_{ a}n are the length and ascent time of SCs n+2 and n, respectively. The estimated correlation coefficient between the model parameters is 0.93 (0.91) for Version 1 (Version 2) sunspot series. The standard errors in the observed and predicted lengths of the SCs for Version 1 and Version 2 data are 0.38 and 0.44 years, respectively. The advantage of the proposed model is that the predictions of the length of the upcoming two SCs ( i.e., n+1, n+2) are readily available at the time of the peak of SC n. The present model gives a forecast of 11.01, 10.52, and 11.91 years (11.01, 12.20, and 11.68 years) for the length of SCs 24, 25, and 26, respectively, for Version 1 (Version 2).

  20. A model of the solar cycle driven by the dynamo action of the global convection in the solar convection zone

    International Nuclear Information System (INIS)

    Yoshimura, H.

    1975-01-01

    The dynamo equation which represents the longitudinally averaged magnetohydrodynamical action of the global convection influenced by the rotation in the solar convection zone is solved numerically to simulate the solar cycle as an initial boundary-value problem. The radial and latitudinal structure of the dynamo action is parametrized in accordance with the structure of the rotation, and of the global convection especially in such a way as to represent the presence of the two cells of the regeneration action in the radial direction in which the action has opposite signs, which is typical of the regeneration action of the global convection. A nonlinear process is included by assuming that part of the magnetic field energy is dissipated when the magnetic field strength exceeds some critical value; the formation of active regions and subsequent dissipations are thus simulated. By adjusting the parameters within a reasonable range, oscillatory solutions are obtained to simulate the solar cycle with the period of the right order of magnitude and with the patterns of evolution of the latitudinal distribution of the toroidal component of the magnetic field similar to the observed Butterfly Diagram of sunspots. The evolution of the latitudinal distribution of the radial component of the magnetic field shows patterns similar to the Butterfly Diagram, but having two branches of different polarity in each hemisphere. The development of the radial structure of the magnetic field associated with the solar cycle is presented. The importance of the poleward migrating branch of the Butterfly Diagram is emphasized in relation to the relative importance of the role of the latitudinal and radial shears of the differential rotation

  1. Orexin receptor expression in the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes of free-living European beavers (Castor fiber L.) in different periods of the reproductive cycle.

    Science.gov (United States)

    Czerwinska, Joanna; Chojnowska, Katarzyna; Kaminski, Tadeusz; Bogacka, Iwona; Smolinska, Nina; Kaminska, Barbara

    2017-01-01

    Orexins are hypothalamic neuropeptides acting via two G protein-coupled receptors in mammals: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). In European beavers, which are seasonally breeding animals, the presence and functions of orexins and their receptors remain unknown. Our study aimed to determine the expression of OXR mRNAs and the localization of OXR proteins in hypothalamic-pituitary-adrenal/gonadal (HPA/HPG) axes in free-living beavers. The expression of OXR genes (OX1R, OX2R) and proteins was found in all analysed tissues during three periods of beavers' reproductive cycle (April, July, November). The expression of OXR mRNAs in the beaver HPA axis varied seasonally (Ppituitary and adrenals, OX1R mRNA levels were relatively constant in females and peaked in July in males (P<0.05), whereas the OX2R was most highly expressed in males in November and in females in April (P<0.05). In gonads, OX1R expression did not fluctuate between seasons or sexes, but transcript levels were elevated in the testes in November and in the ovaries in July (P<0.05). In turn, OX2R mRNA levels varied between the sexes (P<0.05) and were higher in females (July and November) than in males (P<0.05). The circannual variations in OXR mRNA levels in HPA and HPG axes suggest that the expression of these receptors is associated with sex-specific changes in beavers' reproductive activity and their environmental adaptations. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. HIGH RESOLUTION He i 10830 Å NARROW-BAND IMAGING OF AN M-CLASS FLARE. I. ANALYSIS OF SUNSPOT DYNAMICS DURING FLARING

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ya; Su, Yingna; Hong, Zhenxiang; Ji, Haisheng [Key Laboratory of DMSA, Purple Mountain Observatory, CAS, Nanjing, 210008 (China); Zeng, Zhicheng; Goode, Philip R.; Cao, Wenda [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Ji, Kaifan [Yunnan Astronomical Observatories, Kunming 650011 (China)

    2016-12-20

    In this paper, we report our first-step results of high resolution He i 10830 Å narrow-band imaging (bandpass: 0.5 Å) of an M1.8 class two-ribbon flare on 2012 July 5. The flare was observed with the 1.6 m aperture New Solar Telescope at Big Bear Solar Observatory. For this unique data set, sunspot dynamics during flaring were analyzed for the first time. By directly imaging the upper chromosphere, running penumbral waves are clearly seen as an outward extension of umbral flashes; both take the form of absorption in the 10830 Å narrow-band images. From a space–time image made of a slit cutting across a flare ribbon and the sunspot, we find that the dark lanes for umbral flashes and penumbral waves are obviously broadened after the flare. The most prominent feature is the sudden appearance of an oscillating absorption strip inside the ribbon when it sweeps into the sunspot’s penumbral and umbral regions. During each oscillation, outwardly propagating umbral flashes and subsequent penumbral waves rush out into the inwardly sweeping ribbon, followed by a return of the absorption strip with similar speed. We tentatively explain the phenomena as the result of a sudden increase in the density of ortho-helium atoms in the area of the sunspot being excited by the flare’s extreme ultraviolet illumination. This explanation is based on the observation that 10830 Å absorption around the sunspot area gets enhanced during the flare. Nevertheless, questions are still open and we need further well-devised observations to investigate the behavior of sunspot dynamics during flares.

  3. Cosmophysical periods in European history

    International Nuclear Information System (INIS)

    Vladimirskij, B.M.; Kislovskij, L.D.

    1995-01-01

    In social systems there are rhythms synchronised by cosmical periods. These rhythms have partly biological origin. Some natural cycles also might influence upon historical processes (as such as climatic and epidemical). The analysis of the literature shows that there is rhythmic component in European history where solar activity cycles -11 and 340 years are presented. 17 refs., 2 tabs

  4. DATA ASSIMILATION APPROACH FOR FORECAST OF SOLAR ACTIVITY CYCLES

    Energy Technology Data Exchange (ETDEWEB)

    Kitiashvili, Irina N., E-mail: irina.n.kitiashvili@nasa.gov [NASA Ames Research Center, Moffett Field, Mountain View, CA 94035 (United States)

    2016-11-01

    Numerous attempts to predict future solar cycles are mostly based on empirical relations derived from observations of previous cycles, and they yield a wide range of predicted strengths and durations of the cycles. Results obtained with current dynamo models also deviate strongly from each other, thus raising questions about criteria to quantify the reliability of such predictions. The primary difficulties in modeling future solar activity are shortcomings of both the dynamo models and observations that do not allow us to determine the current and past states of the global solar magnetic structure and its dynamics. Data assimilation is a relatively new approach to develop physics-based predictions and estimate their uncertainties in situations where the physical properties of a system are not well-known. This paper presents an application of the ensemble Kalman filter method for modeling and prediction of solar cycles through use of a low-order nonlinear dynamo model that includes the essential physics and can describe general properties of the sunspot cycles. Despite the simplicity of this model, the data assimilation approach provides reasonable estimates for the strengths of future solar cycles. In particular, the prediction of Cycle 24 calculated and published in 2008 is so far holding up quite well. In this paper, I will present my first attempt to predict Cycle 25 using the data assimilation approach, and discuss the uncertainties of that prediction.

  5. Problem Periods

    Science.gov (United States)

    ... ovary syndrome. Read our information on PCOS for teens , and see your doctor if you think you may have PCOS. Major weight loss. Girls who have anorexia will often stop having periods. When to see ...

  6. Entrepreneurship and the Business Cycle

    NARCIS (Netherlands)

    Ph.D. Koellinger (Philipp); A.R. Thurik (Roy)

    2011-01-01

    textabstractWe find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972-2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment

  7. REGULARITY OF THE NORTH–SOUTH ASYMMETRY OF SOLAR ACTIVITY: REVISITED

    International Nuclear Information System (INIS)

    Zhang, J.; Feng, W.

    2015-01-01

    Extended time series of Solar Activity Indices (ESAI) extended the Greenwich series of sunspot area from the year 1874 back to 1821. The ESAI's yearly sunspot area in the northern and southern hemispheres from 1821 to 2013 is utilized to investigate characteristics of the north–south hemispherical asymmetry of sunspot activity. Periodical behavior of about 12 solar cycles is also confirmed from the ESAI data set to exist in dominant hemispheres, linear regression lines of yearly asymmetry values, and cumulative counts of yearly sunspot areas in the hemispheres for solar cycles. The period is also inferred to appear in both the cumulative difference in the yearly sunspot areas in the hemispheres over the entire time interval and in its statistical Student's t-test. The hemispherical bias of sunspot activity should be regarded as an impossible stochastic phenomenon over a long time period

  8. Sulfur cycle

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.

    Microbes, especially bacteria, play an important role in oxidative and reductive cycle of sulfur. The oxidative part of the cycle is mediated by photosynthetic bacteria in the presence of light energy and chemosynthetic forms in the absence of light...

  9. Size of the coming solar cycle 24 based on Ohl's Precursor Method, final estimate

    Directory of Open Access Journals (Sweden)

    R. P. Kane

    2010-07-01

    Full Text Available In Ohl's Precursor Method (Ohl, 1966, 1976, the geomagnetic activity during the declining phase of a sunspot cycle is shown to be well correlated with the size (maximum sunspot number Rz(max of the next cycle. For solar cycle 24, Kane (2007a used aa(min=15.5 (12-month running mean, which occurred during March–May of 2006 and made a preliminary estimate Rz(max=124±26 (12-month running mean. However, in the next few months, the aa index first increased and then decreased to a new low value of 14.8 in July 2007. With this new low value, the prediction was Rz(max=117±26 (12-month running mean. However, even this proved a false signal. Since then, the aa values have decreased considerably and the last 12-monthly value is 8.7, centered at May 2009. For solar cycle 24, using aa(min=8.7, the latest prediction is, Rz(max=58.0±25.0.

  10. International Business Cycle Accounting

    OpenAIRE

    Keisuke Otsu

    2009-01-01

    In this paper, I extend the business cycle accounting method a la Chari, Kehoe and McGrattan (2007) to a two-country international business cycle model and quantify the effect of the disturbances in relevant markets on the business cycle correlation between Japan and the US over the 1980-2008 period. This paper finds that disturbances in the labor market and production efficiency are important in accounting for the recent increase in the cross-country output correlation. If international fina...

  11. Stokes profile analysis and vector magnetic fields. III. Extended temperature minima of sunspot umbrae as inferred from Stokes profiles of Mg I 4571 A

    International Nuclear Information System (INIS)

    Lites, B.W.; Skumanich, A.; Rees, D.E.; Murphy, G.A.; Carlsson, M.; Sydney Univ., Australia; Oslo Universitetet, Norway)

    1987-01-01

    Observed Stokes profiles of Mg I 4571 A are analyzed as a diagnostic of the magnetic field and thermal structure at the temperature minimum of sunspot umbrae. Multilevel non-LTE transfer calculations of the Mg I-II-III excitation and ionization balance in model umbral atmospheres show: (1) Mg I to be far less ionized in sunspot umbrae than in the quiet sun, leading to greatly enhanced opacity in 4571 A, and (2) LTE excitation of 4571 A. Existing umbral models predict emission cores of the Stokes I profile due to the chromospheric temperature rise. This feature is not present in observed umbral profiles. Moreover, such an emission reversal causes similar anomalous features in the Stokes Q, U, V profiles, which are also not observed. Umbral atmospheres with extended temperature minima are suggested. Implications for chromospheric heating mechanisms and the utility of this line for solar vector magnetic field measurements are discussed. 35 references

  12. TRANSITION-REGION/CORONAL SIGNATURES AND MAGNETIC SETTING OF SUNSPOT PENUMBRAL JETS: HINODE (SOT/FG), Hi-C, AND SDO/AIA OBSERVATIONS

    International Nuclear Information System (INIS)

    Tiwari, Sanjiv K.; Moore, Ronald L.; Winebarger, Amy R.; Alpert, Shane E.

    2016-01-01

    Penumbral microjets (PJs) are transient narrow bright features in the chromosphere of sunspot penumbrae, first characterized by Katsukawa et al. using the Ca ii H-line filter on Hinode's Solar Optical Telescope (SOT). It was proposed that the PJs form as a result of reconnection between two magnetic components of penumbrae (spines and interspines), and that they could contribute to the transition region (TR) and coronal heating above sunspot penumbrae. We propose a modified picture of formation of PJs based on recent results on the internal structure of sunspot penumbral filaments. Using data of a sunspot from Hinode/SOT, High Resolution Coronal Imager, and different passbands of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we examine whether PJs have signatures in the TR and corona. We find hardly any discernible signature of normal PJs in any AIA passbands, except for a few of them showing up in the 1600 Å images. However, we discovered exceptionally stronger jets with similar lifetimes but bigger sizes (up to 600 km wide) occurring repeatedly in a few locations in the penumbra, where evidence of patches of opposite-polarity fields in the tails of some penumbral filaments is seen in Stokes-V images. These tail PJs do display signatures in the TR. Whether they have any coronal-temperature plasma is unclear. We infer that none of the PJs, including the tail PJs, directly heat the corona in active regions significantly, but any penumbral jet might drive some coronal heating indirectly via the generation of Alfvén waves and/or braiding of the coronal field

  13. DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES

    International Nuclear Information System (INIS)

    Tlatov, Andrey G.; Vasil'eva, Valerya V.; Pevtsov, Alexei A.

    2010-01-01

    We employ synoptic full disk longitudinal magnetograms to study latitudinal distribution and orientation (tilt) of magnetic bipoles in the course of sunspot activity during cycles 21, 22, and 23. The data set includes daily observations from the National Solar Observatory at Kitt Peak (1975-2002) and Michelson Doppler Imager on board the Solar and Heliospheric Observatory (MDI/SOHO, 1996-2009). Bipole pairs were selected on the basis of proximity and flux balance of two neighboring flux elements of opposite polarity. Using the area of the bipoles, we have separated them into small quiet-Sun bipoles (QSBs), ephemeral regions (ERs), and active regions (ARs). We find that in their orientation, ERs and ARs follow Hale-Nicholson polarity rule. As expected, AR tilts follow Joy's law. ERs, however, show significantly larger tilts of opposite sign for a given hemisphere. QSBs are randomly oriented. Unlike ARs, ERs also show a preference in their orientation depending on the polarity of the large-scale magnetic field. These orientation properties may indicate that some ERs may form at or near the photosphere via the random encounter of opposite polarity elements, while others may originate in the convection zone at about the same location as ARs. The combined latitudinal distribution of ERs and ARs exhibits a clear presence of Spoerer's butterfly diagram (equatorward drift in the course of a solar cycle). ERs extend the ARs' 'wing' of the butterfly diagram to higher latitudes. This high latitude extension of ERs suggests an extended solar cycle with the first magnetic elements of the next cycle developing shortly after the maximum of the previous cycle. The polarity orientation and tilt of ERs may suggest the presence of poloidal fields of two configurations (new cycle and old cycle) in the convection zone at the declining phase of the sunspot cycle.

  14. Hotspots and sunspots - Surface tracers of deep mantle convection in the earth and sun

    Science.gov (United States)

    Stothers, Richard B.

    1993-01-01

    The evolution of the hot-spot distribution on earth in time and space is investigated using available age data. The statistics of continental flood basalt eruptions suggests the formation of a total of about 40 hot spots worldwide during the Cenozoic and Mesozoic, with no true antipodal pairs found. It was found that hot spots tend to concentrate mainly in mid-latitudes, but the pattern of new appearances of hot spots may migrate from high to low latitudes in both hemispheres in long cycles, and may also drift in longitude, although much more slowly prograde.

  15. Quasi-biennial periodicity in the solar neutrino flux and its relation to the solar structure

    International Nuclear Information System (INIS)

    Sakurai, K.

    1981-01-01

    By analysing the observed results on the neutrino flux from the Sun for the years 1970-1978, it is shown that the production rate of the neutrinos at the central core of the Sun had been varying with a period almost equal to 26 months for these years. This so-called 'quasi-biennial' periodicity in this rate suggests that the physical state of the central core of the Sun must have been modulated with this period through the variation of physical parameters as temperature and the chemial composition at the central core of the Sun. An idea to interpret this observed periodicity is thus proposed by taking the variations of these parameters into consideration. Some supporting evidence on this periodicity can be found on the variations of the solar activity as the relative sunspot numbers and the equatorial rotation speed of the Sun. (orig.)

  16. The effect of line damping, magneto-optics and parasitic light on the derivation of sunspot vector magnetic fields

    Science.gov (United States)

    Skumanich, A.; Lites, B. W.

    1985-01-01

    The least square fitting of Stokes observations of sunspots using a Milne-Eddington-Unno model appears to lead, in many circumstances, to various inconsistencies such as anomalously large doppler widths and, hence, small magnetic fields which are significantly below those inferred solely from the Zeeman splitting in the intensity profile. It is found that the introduction of additional physics into the model such as the inclusion of damping wings and magneto-optic birefrigence significantly improves the fit to Stokes parameters. Model fits excluding the intensity profile, i.e., of both magnitude as well as spectral shape of the polarization parameters alone, suggest that parasitic light in the intensity profile may also be a source of inconsistencies. The consequences of the physical changes on the vector properties of the field derived from the Fe I lambda 6173 line for the 17 November 1975 spot as well as on the thermodynamic state are discussed. A Doppler width delta lambda (D) - 25mA is bound to be consistent with a low spot temperature and microturbulence, and a damping constant of a = 0.2.

  17. Dynamics of Subarcsecond Bright Dots in the Transition Region above Sunspots and Their Relation to Penumbral Micro-jets

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, Tanmoy; Banerjee, Dipankar [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Tian, Hui [School of Earth and Space Sciences, Peking University (China); Schanche, Nicole, E-mail: tsamanta@iiap.res.in, E-mail: huitian@pku.edu.cn, E-mail: dipu@iiap.res.in, E-mail: ns81@st-andrews.ac.uk [University of St. Andrews, St. Andrews (United Kingdom)

    2017-02-01

    Recent high-resolution observations have revealed that subarcsecond bright dots (BDs) with sub-minute lifetimes appear ubiquitously in the transition region (TR) above sunspot penumbra. The presence of penumbral micro-jets (PMJs) in the chromosphere was previously reported. It was proposed that both the PMJs and BDs are formed due to a magnetic reconnection process and may play an important role in heating of the penumbra. Using simultaneous observations of the chromosphere from the Solar Optical Telescope (SOT) on board Hinode and observations of the TR from the Interface Region Imaging Spectrograph , we study the dynamics of BDs and their relation to PMJs. We find two types of BDs, one that is related to PMJs, and another that does not show any visible dynamics in the SOT Ca ii H images. From a statistical analysis we show that these two types have different properties. The BDs that are related to PMJs always appear at the top of the PMJs, the vast majority of which show inward motion and originate before the generation of the PMJs. These results may indicate that the reconnection occurs at the lower coronal/TR height and initiates PMJs at the chromosphere. This formation mechanism is in contrast with the formation of PMJs by reconnection in the (upper) photosphere between differently inclined fields.

  18. The Harm that Underestimation of Uncertainty Does to Our Community: A Case Study Using Sunspot Area Measurements

    Science.gov (United States)

    Munoz-Jaramillo, Andres

    2017-08-01

    Data products in heliospheric physics are very often provided without clear estimates of uncertainty. From helioseismology in the solar interior, all the way to in situ solar wind measurements beyond 1AU, uncertainty estimates are typically hard for users to find (buried inside long documents that are separate from the data products), or simply non-existent.There are two main reasons why uncertainty measurements are hard to find:1. Understanding instrumental systematic errors is given a much higher priority inside instrumental teams.2. The desire to perfectly understand all sources of uncertainty postpones indefinitely the actual quantification of uncertainty in our measurements.Using the cross calibration of 200 years of sunspot area measurements as a case study, in this presentation we will discuss the negative impact that inadequate measurements of uncertainty have on users, through the appearance of toxic and unnecessary controversies, and data providers, through the creation of unrealistic expectations regarding the information that can be extracted from their data. We will discuss how empirical estimates of uncertainty represent a very good alternative to not providing any estimates at all, and finalize by discussing the bare essentials that should become our standard practice for future instruments and surveys.

  19. Solar cycle predicts folate-sensitive neonatal genotypes at discrete phases of the first trimester of pregnancy: a novel folate-related human embryo loss hypothesis.

    Science.gov (United States)

    Lucock, Mark; Glanville, Tracey; Yates, Zoë; Walker, James; Furst, John; Simpson, Nigel

    2012-08-01

    Folate, a key periconceptional nutrient, is ultraviolet light (UV-R) sensitive. We therefore hypothesise that a relationship exists between sunspot activity, a proxy for total solar irradiance (particularly UV-R) reaching Earth, and the occurrence of folate-sensitive, epigenomic-related neonatal genotypes during the first trimester of pregnancy. Limited data is provided to support the hypothesis that the solar cycle predicts folate-related human embryo loss: 379 neonates born at latitude 54°N between 1998 and 2000 were examined for three folate-sensitive, epigenome-related polymorphisms, with solar activity for trimester one accessed via the Royal Greenwich Observatory-US Air force/National Oceanic and Atmospheric Administration Sunspot Database (34,110 total observation days). Logistic regression showed solar activity predicts C677T-methylenetetrahydrofolate reductase (C677T-MTHFR) and A66G-methionine synthase reductase (A66G-MSR) genotype at discrete phases of trimester one. Total and maximal sunspot activity predicts C677T-MTHFR genotype for days 31-60 of trimester one (p=0.0181 and 0.0366, respectively) and A66G-MSR genotype for days 61-90 of trimester one (p=0.0072 and 0.0105, respectively). Loss of UV-R sensitive folate associated with the sunspot cycle might therefore interact with variant folate genes to perturb DNA methylation and/or elaboration of the primary base sequence (thymidylate synthesis), as well as increase embryo-toxic homocysteine. We hypothesise that this may influence embryo viability leading to 677CC-MTHFR and 66GG-MSR embryo loss at times of increased solar activity. This provides an interesting and plausible link between well recognised 'folate gene originated developmental disorders' and 'solar activity/seasonality modulated developmental disorders'. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Solar cycles and climate variations

    International Nuclear Information System (INIS)

    Chistyakov, V.F.

    1990-01-01

    Climate oscillations with 100-, 200- and 300-year periods are positively correlated with solar activity oscillations: the higher is solar activity the warmer is climate. According to geological data (varved clays) it is determined, that length of cycles has decreased from 23.4 up to 11 years during latter 2.5 billion years. 12-year cycles occurred during the great glaciation periods, while 10-year cycles occurred during interglaciation periods. It is suggested, that these oscillations are related with variations of the solar activity and luminescence

  1. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...... teacher employment patterns at the state level in Germany and find strong evidence of cycling mechanisms, in the form of electioneering and honeymooning. Against a backdrop of a continuously shrinking total teachers' pool, German state-level incumbents accelerate the hiring of new teachers during election...... periods and partly reverse this during politically safer points in the electoral cycle. Cycles are mediated by issue salience: heightened attention to German public schooling after the notorious PISA-2000 tests further strengthens the manipulation of new teacher hiring for electoral purposes....

  2. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    2009-01-01

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...... teacher employment patterns at the state level in Germany and find strong evidence of cycling mechanisms, in the form of electioneering and honeymooning. Against a backdrop of a continuously shrinking total teachers' pool, German state-level incumbents accelerate the hiring of new teachers during election...... periods and partly reverse this during politically safer points in the electoral cycle. Cycles are mediated by issue salience: heightened attention to German public schooling after the notorious PISA-2000 tests further strengthens the manipulation of new teacher hiring for electoral purposes....

  3. A solar cycle of spacecraft anomalies due to internal charging

    Directory of Open Access Journals (Sweden)

    G. L. Wrenn

    Full Text Available It is important to appreciate how the morphology of internal charging of spacecraft systems, due to penetrating electrons, differs from that of the more common surface charging, due to electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so that solar cycle and seasonal dependencies can be clearly established. Concurrent measurements of sunspot number, solar wind speed and 2-day >2 MeV electron fluence are presented to highlight pertinent space weather relationships, and the importance of understanding the complex particle interaction processes involved.

    Key words. Magnetospheric physics (energetic particles; trapped; solar wind – magnetosphere interactions – space plasma physics (spacecraft sheaths, wakes, charging

  4. A solar cycle of spacecraft anomalies due to internal charging

    Directory of Open Access Journals (Sweden)

    G. L. Wrenn

    2002-07-01

    Full Text Available It is important to appreciate how the morphology of internal charging of spacecraft systems, due to penetrating electrons, differs from that of the more common surface charging, due to electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so that solar cycle and seasonal dependencies can be clearly established. Concurrent measurements of sunspot number, solar wind speed and 2-day >2 MeV electron fluence are presented to highlight pertinent space weather relationships, and the importance of understanding the complex particle interaction processes involved.Key words. Magnetospheric physics (energetic particles; trapped; solar wind – magnetosphere interactions – space plasma physics (spacecraft sheaths, wakes, charging

  5. Modeling the solar cycle change in nitric oxide in the thermosphere and upper mesosphere

    International Nuclear Information System (INIS)

    Fuller-Rowell, T.J.

    1993-01-01

    Measurements from the Solar Mesosphere Explorer (SME) satellite have shown that low-latitude nitric oxide densities at 110 km decrease by about a factor of 8 from January 1982 to April 1985. This time period corresponds to the descending phase of the last solar cycle where the monthly smoothed sunspot number decreased from more than 150 to less than 25. In addition, nitric oxide was observed to vary by a factor of 2 over a solar rotation, during high solar activity. A one-dimensional, globally averaged model of the thermosphere and upper mesosphere has been used to study the height distribution of nitric oxide (NO) and its response to changes in the solar extreme ultraviolet radiation (EUV) through the solar cycle and over a solar rotation. The primary source of nitric oxide is the reaction of excited atomic nitrogen, N( 2 D), with molecular oxygen. The atomic nitrogen is created by a number of ion-neutral reactions and by direct dissociation of molecular nitrogen by photons and photoelectrons. The occurrence of the peak nitric oxide density at or below 115 km is a direct consequence of ionization and dissociation of molecular nitrogen by photoelectrons, which are produced by the solar flux below 30.0 nm (XUV). Nitric oxide is shown to vary over the solar cycle by a factor of 7 at low latitudes in the lower thermosphere E region, due to the estimated change in the solar EUV flux, in good agreement with the SME satellite observations. The NO density is shown to be strongly dependent on the temperature profile in the lower thermosphere and accounts for the difference between the current model and previous work. Wavelengths less than 1.8 nm have little impact on the NO profile. A factor of 3 change in solar flux below 5.0 nm at high solar activity produced a factor of 2 change in the peak NO density, consistent with SME observations over a solar rotation; this change also lowered the peak to 100 km, consistent with rocket data. 52 refs., 10 figs., 5 tabs

  6. Glacial cycles

    DEFF Research Database (Denmark)

    Kaufmann, R. K.; Juselius, Katarina

    We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...... and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed...... to simulate glacial cycles accurately. Also, results suggest that non-linear 10 dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles....

  7. TWO NOVEL PARAMETERS TO EVALUATE THE GLOBAL COMPLEXITY OF THE SUN'S MAGNETIC FIELD AND TRACK THE SOLAR CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.; Landi, E. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48105 (United States); Gibson, S. E., E-mail: lzh@umich.edu [NCAR/HAO, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

    2013-08-20

    Since the unusually prolonged and weak solar minimum between solar cycles 23 and 24 (2008-2010), the sunspot number is smaller and the overall morphology of the Sun's magnetic field is more complicated (i.e., less of a dipole component and more of a tilted current sheet) compared with the same minimum and ascending phases of the previous cycle. Nearly 13 yr after the last solar maximum ({approx}2000), the monthly sunspot number is currently only at half the highest value of the past cycle's maximum, whereas the polar magnetic field of the Sun is reversing (north pole first). These circumstances make it timely to consider alternatives to the sunspot number for tracking the Sun's magnetic cycle and measuring its complexity. In this study, we introduce two novel parameters, the standard deviation (SD) of the latitude of the heliospheric current sheet (HCS) and the integrated slope (SL) of the HCS, to evaluate the complexity of the Sun's magnetic field and track the solar cycle. SD and SL are obtained from the magnetic synoptic maps calculated by a potential field source surface model. We find that SD and SL are sensitive to the complexity of the HCS: (1) they have low values when the HCS is flat at solar minimum, and high values when the HCS is highly tilted at solar maximum; (2) they respond to the topology of the HCS differently, as a higher SD value indicates that a larger part of the HCS extends to higher latitude, while a higher SL value implies that the HCS is wavier; (3) they are good indicators of magnetically anomalous cycles. Based on the comparison between SD and SL with the normalized sunspot number in the most recent four solar cycles, we find that in 2011 the solar magnetic field had attained a similar complexity as compared to the previous maxima. In addition, in the ascending phase of cycle 24, SD and SL in the northern hemisphere were on the average much greater than in the southern hemisphere, indicating a more tilted and wavier

  8. Astrophysical implications of periodicity

    International Nuclear Information System (INIS)

    Muller, R.A.

    1988-01-01

    Two remarkable discoveries of the last decade have profound implications for astrophysics and for geophysics. These are the discovery by Alvarez et al., that certain mass extinctions are caused by the impact on the earth of a large asteroid or comet, and the discovery by Raup and Sepkoski that such extinctions are periodic, with a cycle time of 26 to 30 million years. The validity of both of these discoveries is assumed and the implications are examined. Most of the phenomena described depend not on periodicity, but just on the weaker assumption that the impacts on the earth take place primarily in showers. Proposed explanations for the periodicity include galactic oscillations, the Planet X model, and the possibility of Nemesis, a solar companion star. These hypotheses are critically examined. Results of the search for the solar companion are reported. The Deccan flood basalts of India have been proposed as the impact site for the Cretaceous impact, but this hypotheisis is in contradiction with the conclusion of Courtillot et al., that the magma flow began during a period of normal magnetic field. A possible resolution of this contradiction is proposed

  9. Capital-labor substitution and competitive non-linear endogenous business cycles

    NARCIS (Netherlands)

    Grandmont, J.M.; Pintus, P.; de Vilder, R.

    1998-01-01

    We develop simple geometrical methods to study local indeterminacy, bifurcations, and stochastic (sunspot) equilibria near a steady state, in nonlinear two dimensional economic models. We present in particular a simple, constructive, geometrical characterization of the support of stochastic sunspot

  10. Credit cycles and macro fundamentals

    NARCIS (Netherlands)

    Koopman, S.J.; Kraeussl, R.G.W.; Lucas, A.; Monteiro, A.

    2009-01-01

    We use an intensity-based framework to study the relation between macroeconomic fundamentals and cycles in defaults and rating activity. Using Standard and Poor's U.S. corporate rating transition and default data over the period 1980-2005, we directly estimate the default and rating cycle from micro

  11. The influence of short-time period of an adaptation to decreased ambient temperature on interleukin-6 and corticosterone levels in female Wistar strain rats in the proestrous phase of the reproductive cycle.

    Directory of Open Access Journals (Sweden)

    Grazyna Wójcik

    2008-04-01

    Full Text Available To date, there has been little research examining whether short-time changes of external environmental conditions exert any effects on immune responses. The activation of metabolic changes, release of hormones responsive for immunomodulation and the action of interleukins play an important role in interaction with hormones of an anterior pituitary gland in the proestrous phase of the reproductive cycle. The aim of our study was to determine the effects of a short-time change of ambient temperature (30 minutes on interleukin-6 (IL-6 and corticosterone plasma concentration of female rats in the proestrous phase of the reproductive cycle. The climatic chamber with automatically adjustable and monitored internal environmental parameters (temperature, oxygenation, humidity was used during the experiment. The estimation of the vaginal lavage using a microscope was done to determine the estrous cycle. On the day of the experiment, animals were divided into 2 groups: the control group (ambient temperature 21 degrees C +/- 1 degrees C; normoxia 21% O2 and the test group (ambient temperature 10 degrees C +/- 1 degrees C; normoxia 21% O2 stayed in the climatic chamber for 30 minutes. The blood samples were collected before the experiment and after 30, 60, 90, 150 and 210 minutes from the beginning of the experiment. The concentrations of IL-6 and corticosterone were measured in blood plasma samples using ELISA method. There was a significant elevation of IL-6 levels after staying in 10 degrees C during the first 150 minutes from the beginning of the experiment, with the highest value occurring after 60 minutes (426.6 pg/ml; SE - 146.1 with comparison to the value at first sampling (108.5 pg/ml; SE - 29.5; p<0.05 and with comparison to the control group at the same time from the beginning of the experiment (87.6 pg/ml; SE - 2.3; p<0.05. The changed level of corticosterone in the test group in comparison to control group was observed but the differences were

  12. A safety analysis of edaravone (MCI-186) during the first six cycles (24 weeks) of amyotrophic lateral sclerosis (ALS) therapy from the double-blind period in three randomized, placebo-controlled studies.

    Science.gov (United States)

    Kalin, Alexander; Medina-Paraiso, Elvia; Ishizaki, Kaoru; Kim, Alex; Zhang, Yannong; Saita, Takanori; Wasaki, Masahiko

    2017-10-01

    There continues to be a need for new therapies to treat ALS. Provide an overview of safety for edaravone in ALS patients during the first six cycles of treatment. Analysis was based on three randomised, placebo-controlled clinical trials. Endpoints included treatment-emergent adverse events (TEAEs), including AEs leading to discontinuation, serious adverse events (SAEs), and deaths. The analysis included a total of 368 patients (184 in the edaravone group and placebo group, respectively). Of those, 94.6% of the edaravone group and 90.2% of placebo group completed six cycles of therapy. Baseline characteristics were comparable between the two groups. TEAE incidence in the edaravone group and placebo group was 87.5% and 87.0%, respectively. TEAEs ocurring at ≥2% incidence in the edaravone group compared to placebo were contusion (14.7% vs. 8.7%), gait disturbance (12.5% vs. 9.2%), headache (8.2% vs. 5.4%), eczema (6.5% vs. 2.2%), dermatitis contact (6.0% vs. 3.3%), respiratory disorder (4.3% vs. 1.1%), and glucose urine present (3.8% vs. 1.6%). There was no imbalance in TEAEs leading to discontinuation (2.2% [edaravone], and 5.4% [placebo]). SAE incidence was 17.4% in the edaravone group and 22.3% in placebo group. Treatment-emergent deaths occurred in 2.2% in the edaravone group and 1.1% in placebo group, all respiratory in nature and attributed to worsening ALS. Data collected from three double-blind assessments found that while some TEAEs were more common in the edaravone group compared to placebo, the overall incidences of SAEs, deaths, and discontinuations due to AEs were similar or less for edaravone compared to placebo.

  13. Effects of solar activity and galactic cosmic ray cycles on the modulation of the annual average temperature at two sites in southern Brazil

    Science.gov (United States)

    Frigo, Everton; Antonelli, Francesco; da Silva, Djeniffer S. S.; Lima, Pedro C. M.; Pacca, Igor I. G.; Bageston, José V.

    2018-04-01

    Quasi-periodic variations in solar activity and galactic cosmic rays (GCRs) on decadal and bidecadal timescales have been suggested as a climate forcing mechanism for many regions on Earth. One of these regions is southern Brazil, where the lowest values during the last century were observed for the total geomagnetic field intensity at the Earth's surface. These low values are due to the passage of the center of the South Atlantic Magnetic Anomaly (SAMA), which crosses the Brazilian territory from east to west following a latitude of ˜ 26°. In areas with low geomagnetic intensity, such as the SAMA, the incidence of GCRs is increased. Consequently, possible climatic effects related to the GCRs tend to be maximized in this region. In this work, we investigate the relationship between the ˜ 11-year and ˜ 22-year cycles that are related to solar activity and GCRs and the annual average temperature recorded between 1936 and 2014 at two weather stations, both located near a latitude of 26° S but at different longitudes. The first of these stations (Torres - TOR) is located in the coastal region, and the other (Iraí - IRA) is located in the interior, around 450 km from the Atlantic Ocean. Sunspot data and the solar modulation potential for cosmic rays were used as proxies for the solar activity and the GCRs, respectively. Our investigation of the influence of decadal and bidecadal cycles in temperature data was carried out using the wavelet transform coherence (WTC) spectrum. The results indicate that periodicities of 11 years may have continuously modulated the climate at TOR via a nonlinear mechanism, while at IRA, the effects of this 11-year modulation period were intermittent. Four temperature maxima, separated by around 20 years, were detected in the same years at both weather stations. These temperature maxima are almost coincident with the maxima of the odd solar cycles. Furthermore, these maxima occur after transitions from even to odd solar cycles, that is

  14. 24-month fuel cycles

    International Nuclear Information System (INIS)

    Rosenstein, R.G.; Sipes, D.E.; Beall, R.H.; Donovan, E.J.

    1986-01-01

    Twenty-four month reload cycles can potentially lessen total power generation costs. While 24-month cores increase purchased fuel costs, the longer cycles reduce the number of refueling outages and thus enhance plant availability; men-rem exposure to site personnel and other costs associated with reload core design and licensing are also reduced. At dual unit sites an operational advantage can be realized by refueling each plant alternately on a 1-year offset basis. This results in a single outage per site per year which can be scheduled for off-peak periods or when replacement power costs are low

  15. A STATISTICAL STUDY OF FLARE PRODUCTIVITY ASSOCIATED WITH SUNSPOT PROPERTIES IN DIFFERENT MAGNETIC TYPES OF ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ya-Hui [Institute of Space Science, National Central University, Jhongli 32001, Taiwan (China); Hsieh, Min-Shiu [Geophysical Institute, University of Alaska Fairbanks, AK 99775-7320 (United States); Yu, Hsiu-Shan [Center for Astrophysics and Space Sciences, University of California San Diego, CA 92093 (United States); Chen, P. F., E-mail: yhyang@jupiter.ss.ncu.edu.tw, E-mail: mhsieh2@alaska.edu, E-mail: hsyu@ucsd.edu, E-mail: chenpf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)

    2017-01-10

    It is often believed that intense flares preferentially originate from the large-size active regions (ARs) with strong magnetic fields and complex magnetic configurations. This work investigates the dependence of flare activity on the AR properties and clarifies the influence of AR magnetic parameters on the flare productivity, based on two data sets of daily sunspot and flare information as well as the GOES soft X-ray measurements and HMI vector magnetograms. By considering the evolution of magnetic complexity, we find that flare behaviors are quite different in the short- and long-lived complex ARs and the ARs with more complex magnetic configurations are likely to host more impulsive and intense flares. Furthermore, we investigate several magnetic quantities and perform the two-sample Kolmogorov–Smirnov test to examine the similarity/difference between two populations in different types of ARs. Our results demonstrate that the total source field strength on the photosphere has a good correlation with the flare activity in complex ARs. It is noted that intense flares tend to occur at the regions of strong source field in combination with an intermediate field-weighted shear angle. This result implies that the magnetic free energy provided by a complex AR could be high enough to trigger a flare eruption even with a moderate magnetic shear on the photosphere. We thus suggest that the magnetic free energy represented by the source field rather than the photospheric magnetic complexity is a better quantity to characterize the flare productivity of an AR, especially for the occurrence of intense flares.

  16. The Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    2011-08-01

    This brochure describes the nuclear fuel cycle, which is an industrial process involving various activities to produce electricity from uranium in nuclear power reactors. The cycle starts with the mining of uranium and ends with the disposal of nuclear waste. The raw material for today's nuclear fuel is uranium. It must be processed through a series of steps to produce an efficient fuel for generating electricity. Used fuel also needs to be taken care of for reuse and disposal. The nuclear fuel cycle includes the 'front end', i.e. preparation of the fuel, the 'service period' in which fuel is used during reactor operation to generate electricity, and the 'back end', i.e. the safe management of spent nuclear fuel including reprocessing and reuse and disposal. If spent fuel is not reprocessed, the fuel cycle is referred to as an 'open' or 'once-through' fuel cycle; if spent fuel is reprocessed, and partly reused, it is referred to as a 'closed' nuclear fuel cycle.

  17. Predicting the La Niña of 2020-21: Termination of Solar Cycles and Correlated Variance in Solar and Atmospheric Variability

    Science.gov (United States)

    Leamon, R. J.; McIntosh, S. W.

    2017-12-01

    Establishing a solid physical connection between solar and tropospheric variability has posed a considerable challenge across the spectrum of Earth-system science. Over the past few years a new picture to describe solar variability has developed, based on observing, understanding and tracing the progression, interaction and intrinsic variability of the magnetized activity bands that belong to the Sun's 22-year magnetic activity cycle. The intra- and extra-hemispheric interaction of these magnetic bands appear to explain the occurrence of decadal scale variability that primarily manifests itself in the sunspot cycle. However, on timescales of ten months or so, those bands posses their own internal variability with an amplitude of the same order of magnitude as the decadal scale. The latter have been tied to the existence of magnetized Rossby waves in the solar convection zone that result in surges of magnetic flux emergence that correspondingly modulate our star's radiative and particulate output. One of the most important events in the progression of these bands is their (apparent) termination at the solar equator that signals a global increase in magnetic flux emergence that becomes the new solar cycle. We look at the particulate and radiative implications of these termination points, their temporal recurrence and signature, from the Sun to the Earth, and show the correlated signature of solar cycle termination events and major oceanic oscillations that extend back many decades. A combined one-two punch of reduced particulate forcing and increased radiative forcing that result from the termination of one solar cycle and rapid blossoming of another correlates strongly with a shift from El Niño to La Niña conditions in the Pacific Ocean. This shift does not occur at solar minima, nor solar maxima, but at a particular, non-periodic, time in between. The failure to identify these termination points, and their relative irregularity, have inhibited a correlation to be

  18. Resonant behaviour of MHD waves on magnetic flux tubes. I - Connection formulae at the resonant surfaces. II - Absorption of sound waves by sunspots

    Science.gov (United States)

    Sakurai, Takashi; Goossens, Marcel; Hollweg, Joseph V.

    1991-01-01

    The present method of addressing the resonance problems that emerge in such MHD phenomena as the resonant absorption of waves at the Alfven resonance point avoids solving the fourth-order differential equation of dissipative MHD by recourse to connection formulae across the dissipation layer. In the second part of this investigation, the absorption of solar 5-min oscillations by sunspots is interpreted as the resonant absorption of sounds by a magnetic cylinder. The absorption coefficient is interpreted (1) analytically, under certain simplifying assumptions, and numerically, under more general conditions. The observed absorption coefficient magnitude is explained over suitable parameter ranges.

  19. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    -, č. 274 (2005), s. 1-26 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * crises * cycles and fluctuations Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp274.pdf

  20. Happy Cycling

    DEFF Research Database (Denmark)

    Geert Jensen, Birgitte; Nielsen, Tom

    2013-01-01

    og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...

  1. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    2008-01-01

    Roč. 63, č. 1 (2008), s. 308-327 ISSN 0899-8256 Institutional research plan: CEZ:AV0Z70850503 Keywords : global games * coordination * crises * cycles and fluctuations Subject RIV: AH - Economics Impact factor: 1.333, year: 2008

  2. LOW-FREQUENCY OBSERVATIONS OF TRANSIENT QUASI-PERIODIC RADIO EMISSION FROM THE SOLAR ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Sasikumar Raja, K.; Ramesh, R., E-mail: sasikumar@iiap.res.in [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India)

    2013-09-20

    We report low-frequency observations of quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was ≈5.2 s, and their average degree of circular polarization (dcp) was ≈0.12. We calculated the associated magnetic field B (1) using the empirical relationship between the dcp and B for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in B ≈ 4.2 G at the location of the 80 MHz plasma level (radial distance r ≈ 1.3 R{sub ☉}) in the active region corona.

  3. Deciphering Periodic Methanol Masers

    Science.gov (United States)

    Stecklum, Bringfried; Caratti o Garatti, Alessio; Henning, Thomas; Hodapp, Klaus; Hopp, Ulrich; Kraus, Alex; Linz, Hendrik; Sanna, Alberto; Sobolev, Andrej; Wolf, Verena

    2018-05-01

    Impressive progress has been made in recent years on massive star formation, yet the involved high optical depths even at submm/mm wavelengths make it difficult to reveal its details. Recently, accretion bursts of massive YSOs have been identified to cause flares of Class II methanol masers (methanol masers for short) due to enhanced mid-IR pumping. This opens a new window to protostellar accretion variability, and implies that periodic methanol masers hint at cyclic accretion. Pinning down the cause of the periodicity requires joint IR and radio monitoring. We derived the first IR light curve of a periodic maser host from NEOWISE data. The source, G107.298+5.639, is an intermediate-mass YSO hosting methanol and water masers which flare every 34.5 days. Our recent joint K-band and radio observations yielded first but marginal evidence for a phase lag between the rise of IR and maser emission, respectively, and revealed that both NEOWISE and K-band light curves are strongly affected by the light echo from the ambient dust. Both the superior resolution of IRAC over NEOWISE and the longer wavelengths compared to our ground-based imaging are required to inhibit the distractive contamination by the light echo. Thus, we ask for IRAC monitoring of G107 to cover one flare cycle, in tandem with 100-m Effelsberg and 2-m Wendelstein radio and NIR observations to obtain the first high-quality synoptic measurements of this kind of sources. The IR-maser phase lag, the intrinsic shape of the IR light curves and their possible color variation during the cycle allow us to constrain models for the periodic maser excitation. Since methanol masers are signposts of intermediate-mass and massive YSOs, deciphering their variability offers a clue to the dynamics of the accretion-mediated growth of massive stars and their feedback onto the immediate natal environment. The Spitzer light curve of such a maser-hosting YSO would be a legacy science product of the mission.

  4. Multiparameter Cell Cycle Analysis.

    Science.gov (United States)

    Jacobberger, James W; Sramkoski, R Michael; Stefan, Tammy; Woost, Philip G

    2018-01-01

    Cell cycle cytometry and analysis are essential tools for studying cells of model organisms and natural populations (e.g., bone marrow). Methods have not changed much for many years. The simplest and most common protocol is DNA content analysis, which is extensively published and reviewed. The next most common protocol, 5-bromo-2-deoxyuridine S phase labeling detected by specific antibodies, is also well published and reviewed. More recently, S phase labeling using 5'-ethynyl-2'-deoxyuridine incorporation and a chemical reaction to label substituted DNA has been established as a basic, reliable protocol. Multiple antibody labeling to detect epitopes on cell cycle regulated proteins, which is what this chapter is about, is the most complex of these cytometric cell cycle assays, requiring knowledge of the chemistry of fixation, the biochemistry of antibody-antigen reactions, and spectral compensation. However, because this knowledge is relatively well presented methodologically in many papers and reviews, this chapter will present a minimal Methods section for one mammalian cell type and an extended Notes section, focusing on aspects that are problematic or not well described in the literature. Most of the presented work involves how to segment the data to produce a complete, progressive, and compartmentalized cell cycle analysis from early G1 to late mitosis (telophase). A more recent development, using fluorescent proteins fused with proteins or peptides that are degraded by ubiquitination during specific periods of the cell cycle, termed "Fucci" (fluorescent, ubiquitination-based cell cycle indicators) provide an analysis similar in concept to multiple antibody labeling, except in this case cells can be analyzed while living and transgenic organisms can be created to perform cell cycle analysis ex or in vivo (Sakaue-Sawano et al., Cell 132:487-498, 2007). This technology will not be discussed.

  5. Effects of dietary trace mineral sources and levels fed to layers in their second laying cycle on the quality of eggs stored at different temperatures and for different periods

    Directory of Open Access Journals (Sweden)

    ESPB Saldanha

    2010-12-01

    Full Text Available This study aimed at evaluating the effects of trace mineral levels and sources supplemented to diets fed to semi-heavy layers in their second laying cycle on the quality of eggs stored for 14 days at different temperatures. The experimental diets consisted of the inclusion of inorganic trace minerals (T1 - control: 100% ITM and five supplementation levels of organic trace minerals (carboaminophopho chelates (110, 100, 90, 80, and 70% OTM. Trace mineral inclusion levels (mg/kg feed were: T1: control - 100% ITM: Zn (54, Fe (54, Mn (72, Cu (10, I (0.61 Se (0.3; T2 - 110% OTM: Zn (59.4, Fe (59.4, Mn (79.2, Cu (11.88, I (1.21 Se (0.59; T3 - 100%: OTM: Zn (54, Fe (54, Mn (72, Cu (10.8, I (1.10 Se (0.54; T4 - 90% OTM: Zn (48.6, Fe (48.6, Mn (64.8, Cu (9.72, I (0.99 Se (0.49; T5 - 80% OTM: Zn (43.2, Fe (43.2, Mn (57.6, Cu (8.64, I (0.88, Se (0.43; T6 - 70% OTM: Zn (37.8, Fe (37.8, Mn (50.4, Cu (7.56, I (0.77 Se (0.38. A completely randomized experimental design in a split-plot arrangement with 60 treatments of four replicates each was applied. The combination of six diets versus storage temperature (room or under refrigeration was randomized in plots, whereas the sub-plots consisted of storage times (0, 3, 7, 10, and 14 days. Data were submitted to analysis of variance of a model in slip-plots in time using the software package SAS (2000 at 5% probability level. It was concluded that 70% OTM supplementation can be used with no damage to egg quality, independently from storage temperature or time. The quality of refrigerated eggs stored up to 14 days is better than those stored at room temperature.

  6. Fuel cycle

    International Nuclear Information System (INIS)

    Bahm, W.

    1989-01-01

    The situation of the nuclear fuel cycle for LWR type reactors in France and in the Federal Republic of Germany was presented in 14 lectures with the aim to compare the state-of-the-art in both countries. In addition to the momentarily changing fuilds of fuel element development and fueling strategies, the situation of reprocessing, made interesting by some recent developmnts, was portrayed and differences in ultimate waste disposal elucidated. (orig.) [de

  7. Solar cycle dependence of the radial gradient of cosmic ray intensity

    International Nuclear Information System (INIS)

    Allen, J.A.V.

    1988-01-01

    Observation of the interplanetary intensity of cosmic rays (E/sub p/>80 MeV) by Pioneers 10 and 11 now spans a sixteen-year time period 1972--1988 and heliocentric radial distances, r/sub 10/ and r/sub 11/, out to 43.7 AU for Pioneer 10 and 25.8 AU for Pioneer 11. Solar modulation continues to be present at the current distances of both spacecraft. The radial gradient of intensity is measured continuously over the slowly varying, outward moving radial segment Δr = r/sub 10/--r/sub 11/. The 50-day mean values of the gradient G vary systematically and cyclically in phase with solar activity as measured by sunspot number, with a maximum value of about 2.1 percent (AU)/sup -1/ at sunspot maximum and a miminum value of about 1.2 percent (AU)/sup -1/ at sunspot minimum. Thus, the apparent scale size of the heliospheric modulation region as measured by 1/G is about 48 AU at solar max and about 83 AU at solar min: a result that is the inverse of the conjectural inference of Randall and Van Allen [1986] using most of the same body of data but a different analytical point of view. There is persuasive evidence that G is independent of radial distance over the range 2.5 to 34 AU in the mid-point of the segment Δr. No dependence of G on heliographic latitude is evident, but this result does not lend itself to a quantitative statement. copyright American Geophysical Union 1988

  8. The Peculiar Behavior of Halo Coronal Mass Ejections in Solar Cycle 24

    Science.gov (United States)

    Gopalswamy, N.; Xie, H.; Akiyama, S.; Makela, P.; Yashiro, S.; Michalek, G.

    2015-01-01

    We report on the remarkable finding that the halo coronal mass ejections (CMEs) in cycle 24 are more abundant than in cycle 23, although the sunspot number in cycle 24 has dropped by approx. 40%. We also find that the distribution of halo-CME source locations is different in cycle 24: the longitude distribution of halos is much flatter with the number of halos originating at a central meridian distance greater than or equal to 60deg twice as large as that in cycle 23. On the other hand, the average speed and associated soft X-ray flare size are the same in both cycles, suggesting that the ambient medium into which the CMEs are ejected is significantly different. We suggest that both the higher abundance and larger central meridian longitudes of halo CMEs can be explained as a consequence of the diminished total pressure in the heliosphere in cycle 24. The reduced total pressure allows CMEs to expand more than usual making them appear as halos.

  9. Safe cycling!

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    The HSE Unit will be running a cycling safety campaign at the entrances to CERN's restaurants on 14, 15 and 16 May. Pop along to see if they can persuade you to get back in the saddle!   With summer on its way, you might feel like getting your bike out of winter storage. Well, the HSE Unit has come up with some original ideas to remind you of some of the most basic safety rules. This year, the prevention campaign will be focussing on three themes: "Cyclists and their equipment", "The bicycle on the road", and "Other road users". This is an opportunity to think about the condition of your bike as well as how you ride it. From 14 to 16 May, representatives of the Swiss Office of Accident Prevention and the Touring Club Suisse will join members of the HSE Unit at the entrances to CERN's restaurants to give you advice on safe cycling (see box). They will also be organising three activity stands where you can test your knowle...

  10. Cycle 22

    International Nuclear Information System (INIS)

    Kappernman, J.G.; Albertson, V.D.

    1991-01-01

    This paper reports that for many electric utility systems, Solar Cycle 22 has been the first introduction to the phenomena of Geomagnetic Disturbances and the disrupting and damaging effects that they can have upon modern power systems. For all intents and purposes, Power Industry awareness of Cycle 22 started with a bang during the Great Geomagnetic Storm of March 13, 1989. This storm caused a blackout to the entire Province of Quebec, permanently damaged a large nuclear plant GSU transformer in New Jersey, and created enough havoc across the entire North American power grid to create the plausible threat of a massive power system blackout. The flurry of activity and investigation that followed has led many engineers to realize that their power systems are indeed vulnerable to this phenomena and if anything are becoming ever more vulnerable as the system grows to meet future requirements. As a result some organizations such as Hydro Quebec, PSE and G, and the PJM Pool now implement strategic measures as a remedial response to detection of geomagnetic storm conditions. Many more companies pay particularly close attention to storm forecasts and alerts, and the industry in general has accelerated research and monitoring activities through their own means of in concert with the Electric Power Research Institute (EPRI)

  11. Solar Indices - Sunspot Numbers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  12. On the possible relations between solar activities and global seismicity in the solar cycle 20 to 23

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani, E-mail: dhani@as.itb.ac.id [Astronomy Research Division and Bosscha Observatory, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia); Arif, Johan [Geology Research Division, Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia); Nurzaman, Muhamad Zamzam; Astuti, Isna Kusuma Dewi [Astronomy Study Program, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia)

    2015-09-30

    Solar activities consist of high energetic particle streams, electromagnetic radiation, magnetic and orbital gravitational forces. The well-know solar activity main indicator is the existence of sunspot which has mean variation in 11 years, named by solar cycle, allow for the above fluctuations. Solar activities are also related to the space weather affecting all planetary atmospheric variability, moreover to the Earth’s climate variability. Large extreme space and geophysical events (high magnitude earthquakes, explosive volcanic eruptions, magnetic storms, etc.) are hazards for humankind, infrastructure, economies, technology and the activities of civilization. With a growing world population, and with modern reliance on delicate technological systems, human society is becoming increasingly vulnerable to natural hazardous events. The big question arises to the relation between solar forcing energy to the Earth’s global seismic activities. Estimates are needed for the long term occurrence-rate probabilities of these extreme natural hazardous events. We studied connectivity from yearly seismic activities that refer to and sunspot number within the solar cycle 20 to 23 of year 1960 to 2013 (53 years). We found clear evidences that in general high magnitude earthquake events and their depth were related to the low solar activity.

  13. On the possible relations between solar activities and global seismicity in the solar cycle 20 to 23

    Science.gov (United States)

    Herdiwijaya, Dhani; Arif, Johan; Nurzaman, Muhamad Zamzam; Astuti, Isna Kusuma Dewi

    2015-09-01

    Solar activities consist of high energetic particle streams, electromagnetic radiation, magnetic and orbital gravitational forces. The well-know solar activity main indicator is the existence of sunspot which has mean variation in 11 years, named by solar cycle, allow for the above fluctuations. Solar activities are also related to the space weather affecting all planetary atmospheric variability, moreover to the Earth's climate variability. Large extreme space and geophysical events (high magnitude earthquakes, explosive volcanic eruptions, magnetic storms, etc.) are hazards for humankind, infrastructure, economies, technology and the activities of civilization. With a growing world population, and with modern reliance on delicate technological systems, human society is becoming increasingly vulnerable to natural hazardous events. The big question arises to the relation between solar forcing energy to the Earth's global seismic activities. Estimates are needed for the long term occurrence-rate probabilities of these extreme natural hazardous events. We studied connectivity from yearly seismic activities that refer to and sunspot number within the solar cycle 20 to 23 of year 1960 to 2013 (53 years). We found clear evidences that in general high magnitude earthquake events and their depth were related to the low solar activity.

  14. Biogeochemical cycles

    NARCIS (Netherlands)

    Reijnders, L.; Boersema, J.J.; Reijnders, L.

    2009-01-01

    It is now often assumed that life first appeared on planet Earth about 3,500 million years ago. Since then ‘our’ Sun has changed considerably. While the flux of solar energy to the Earth has increased by about 30% over this period, though, this has not led to a corresponding increase in the Earth's

  15. Cycling infrastructure for reducing cycling injuries in cyclists.

    Science.gov (United States)

    Mulvaney, Caroline A; Smith, Sherie; Watson, Michael C; Parkin, John; Coupland, Carol; Miller, Philip; Kendrick, Denise; McClintock, Hugh

    2015-12-10

    reducing the risk of collision. Generally, the conversion of intersections to roundabouts may increase the number of cycle collisions. In particular, the conversion of intersections to roundabouts with cycle lanes marked as part of the circulating carriageway increased cycle collisions. However, the conversion of intersections with and without signals to roundabouts with cycle paths may reduce the odds of collision. Both continuing a cycle lane across the mouth of a side road with a give way line onto the main road, and cycle tracks, may increase the risk of injury collisions in cyclists. However, these conclusions are uncertain, being based on a narrative review of findings from included studies. There is a lack of evidence that cycle paths or advanced stop lines either reduce or increase injury collisions in cyclists. There is also insufficient evidence to draw any robust conclusions concerning the effect of cycling infrastructure on cycling collisions in terms of severity of injury, sex, age, and level of social deprivation of the casualty.In terms of quality of the evidence, there was little matching of intervention and control sites. In many studies, the comparability of the control area to the intervention site was unclear and few studies provided information on other cycling infrastructures that may be in place in the control and intervention areas. The majority of studies analysed data routinely collected by organisations external to the study team, thus reducing the risk of bias in terms of systematic differences in assessing outcomes between the control and intervention groups. Some authors did not take regression-to-mean effects into account when examining changes in collisions. Longer data collection periods pre- and post-installation would allow for regression-to-mean effects and also seasonal and time trends in traffic volume to be observed. Few studies adjusted cycle collision rates for exposure. Generally, there is a lack of high quality evidence to be able

  16. Unstable periodic orbits and chaotic economic growth

    International Nuclear Information System (INIS)

    Ishiyama, K.; Saiki, Y.

    2005-01-01

    We numerically find many unstable periodic solutions embedded in a chaotic attractor in a macroeconomic growth cycle model of two countries with different fiscal policies, and we focus on a special type of the unstable periodic solutions. It is confirmed that chaotic behavior represented by the model is qualitatively and quantitatively related to the unstable periodic solutions. We point out that the structure of a chaotic solution is dissolved into a class of finite unstable periodic solutions picked out among a large number of periodic solutions. In this context it is essential for the unstable periodic solutions to be embedded in the chaotic attractor

  17. Wind Magnetic Clouds for the Period 2013 - 2015: Model Fitting, Types, Associated Shock Waves, and Comparisons to Other Periods

    Science.gov (United States)

    Lepping, R. P.; Wu, C.-C.; Berdichevsky, D. B.; Szabo, A.

    2018-04-01

    We give the results of parameter fitting of the magnetic clouds (MCs) observed by the Wind spacecraft for the three-year period 2013 to the end of 2015 (called the "Present" period) using the MC model of Lepping, Jones, and Burlaga ( J. Geophys. Res. 95, 11957, 1990). The Present period is almost coincident with the solar maximum of the sunspot number, which has a broad peak starting in about 2012 and extending to almost 2015. There were 49 MCs identified in the Present period. The modeling gives MC quantities such as size, axial attitude, field handedness, axial magnetic-field strength, center time, and closest-approach vector. Derived quantities are also estimated, such as axial magnetic flux, axial current density, and total axial current. Quality estimates are assigned representing excellent, fair/good, and poor. We provide error estimates on the specific fit parameters for the individual MCs, where the poor cases are excluded. Model-fitting results that are based on the Present period are compared to the results of the full Wind mission from 1995 to the end of 2015 (Long-term period), and compared to the results of two other recent studies that encompassed the periods 2007 - 2009 and 2010 - 2012, inclusive. We see that during the Present period, the MCs are, on average, slightly slower, slightly weaker in axial magnetic field (by 8.7%), and larger in diameter (by 6.5%) than those in the Long-term period. However, in most respects, the MCs in the Present period are significantly closer in characteristics to those of the Long-term period than to those of the two recent three-year periods. However, the rate of occurrence of MCs for the Long-term period is 10.3 year^{-1}, whereas this rate for the Present period is 16.3 year^{-1}, similar to that of the period 2010 - 2012. Hence, the MC occurrence rate has increased appreciably in the last six years. MC Type (N-S, S-N, All N, All S, etc.) is assigned to each MC; there is an inordinately large percentage of All S

  18. Limit cycles in quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Patrick

    2015-04-27

    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  19. Geometrical relationship of flare-generated solar wind structures to the magnetic axes of bipolar sunspot groups adjacent to their originating solar flares

    International Nuclear Information System (INIS)

    Ivanov, K.G.; Evdokimova, L.V.; Mikerina, N.V.

    1982-01-01

    Occurrences of interplanetary shock waves near the Earth after the powerful isolated flares of 1957-1978 are investigated. The close connection between the occurrences of shock waves and the positions of magnetic axes of bipolar groups of sunspots is suggested on the basis of a statistical study. The shock waves are principally observed when the Earth finds itself near the planes that are projected through the flares in parallel to the appropriate magnetic axes of the nearest bipolar groups. This regularity is interpreted as an indirect argument for a three-dimensional geometry for the interplanetary shock waves which, when projected on these flattened to corresponding planes, are traces of large circular arcs. The typical angular scales of isolated interplanetary shock waves are estimated as approx. equal to 150 0 and approx. equal to 30 0 parallel and perpendicular, respectively, to the magnetic axes correspondingly. (orig.)

  20. Bifurcations of heterodimensional cycles with two saddle points

    Energy Technology Data Exchange (ETDEWEB)

    Geng Fengjie [School of Information Technology, China University of Geosciences (Beijing), Beijing 100083 (China)], E-mail: gengfengjie_hbu@163.com; Zhu Deming [Department of Mathematics, East China Normal University, Shanghai 200062 (China)], E-mail: dmzhu@math.ecnu.edu.cn; Xu Yancong [Department of Mathematics, East China Normal University, Shanghai 200062 (China)], E-mail: yancongx@163.com

    2009-03-15

    The bifurcations of 2-point heterodimensional cycles are investigated in this paper. Under some generic conditions, we establish the existence of one homoclinic loop, one periodic orbit, two periodic orbits, one 2-fold periodic orbit, and the coexistence of one periodic orbit and heteroclinic loop. Some bifurcation patterns different to the case of non-heterodimensional heteroclinic cycles are revealed.

  1. Bifurcations of heterodimensional cycles with two saddle points

    International Nuclear Information System (INIS)

    Geng Fengjie; Zhu Deming; Xu Yancong

    2009-01-01

    The bifurcations of 2-point heterodimensional cycles are investigated in this paper. Under some generic conditions, we establish the existence of one homoclinic loop, one periodic orbit, two periodic orbits, one 2-fold periodic orbit, and the coexistence of one periodic orbit and heteroclinic loop. Some bifurcation patterns different to the case of non-heterodimensional heteroclinic cycles are revealed.

  2. Energy basis of disasters and the cycles of order and disorder

    International Nuclear Information System (INIS)

    Alexander, J.F. Jr.

    1978-01-01

    A quantitative theory of cycles order and disorder was applied to the earth and evaluated to form an energy basis for the global cycles, surges, and disasters. Energy circuit language was used to diagram the world system and show a common pattern in the order--disorder processes. Storms, floods, forest fires, volcanic eruptions, earthquakes, urban fires, and wars were modeled as the catastrophic release of energy previously converged and stored. Released energy disordered and recycled material available to stimulate a new cycle of growth. Cascading of catastrophic processes of disasters was modeled with a world web. The feedback in the global energy web was provided by the control action of disaster pulses. The global model was presented in both diagrammatic and differential equation form with the energy flows and storages evaluated. Order--disorder models of the atmospheric, oceanic, biological, geological, and urban systems of earth were connected to form an energy convergence network. The global energy model was used to calculate energy quality factors (ratio of energy of one type generating energy of another type) for the earth's major energy transformations. The theory provided suggestions for land-use policy. Energy ratios that provide a quantitative basis for disaster planning can be developed for a local environment of pulsing energy. Possibilities were considered that cycles of order and disorder of the earth are synchronized by cycles of sunspots. Energy quality and pulse amplifier ratios of solar flares may be high enough to control many global cycles

  3. Carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, J; Halbritter, G; Neumann-Hauf, G

    1982-05-01

    This report contains a review of literature on the subjects of the carbon cycle, the increase of the atmospheric CO/sub 2/ concentration and the possible impacts of an increased CO/sub 2/ concentration on the climate. In addition to this survey, the report discusses the questions that are still open and the resulting research needs. During the last twenty years a continual increase of the atmospheric carbon dioxide concentration by about 1-2 ppm per years has been observed. In 1958 the concentration was 315 ppm and this increased to 336 ppm in 1978. A rough estimate shows that the increase of the atmospheric carbon dioxide concentration is about half of the amount of carbon dioxide added to the atmosphere by the combustion of fossil fuels. Two possible sinks for the CO/sub 2/ released into the atmosphere are known: the ocean and the biota. The role of the biota is, however, unclear, since it can act both as a sink and as a source. Most models of the carbon cycle are one-dimensional and cannot be used for accurate predictions. Calculations with climate models have shown that an increased atmospheric CO/sub 2/ concentration leads to a warming of the earth's surface and lower atmosphere. Calculations show that a doubling of the atmospheric CO/sub 2/-concentration would lead to a net heating of the lower atmosphere and earth's surface by a global average of about 4 W m/sup -2/. Greater uncertainties arise in estimating the change in surface temperature resulting from this change in heating rate. It is estimated that the global average annual surface temperature would change between 1.5 and 4.5 K. There are, however, latitudinal and seasonal variations of the impact of increased CO/sub 2/ concentration. Other meteorological variables (e.g. precipitation, wind speed etc.) would also be changed. It appears that the impacts of the other products of fossil fuel combustion are unlikely to counteract the impacts of CO/sub 2/ on the climate.

  4. The Geologic Nitrogen Cycle

    Science.gov (United States)

    Johnson, B. W.; Goldblatt, C.

    2013-12-01

    N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

  5. The urea cycle disorders.

    Science.gov (United States)

    Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

    2014-07-01

    The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  6. International Business Cycle

    Directory of Open Access Journals (Sweden)

    Marek Lubiński

    2007-04-01

    Full Text Available Prime stylized facts of international business cycle theory refer to positive correlation in the cyclical components of important macroeconomic variables across countries. However a number of indicators of business cycle synchronization do not point to clear trends. It can be ascribed to the fact that different forces influence level of business cycle correlation. When investigating into the forces behind the commonness in aggregate fluctuations economic research seems to have pointed in two directions. One strand of the literature examines the idea of common exogenous shocks that affect economies simultaneously. In addition to that economic interdependencies such as trade in goods and services or capital account transactions may serve as the channels through which disturbances spill over across countries.The observed degree of output co movement reflects both the nature of the shocks that have occurred and the degree of economic interdependence. In the periods when common shocks prevail level of synchronization is usually higher than in times of transmission dominance.

  7. Detecting periodic oscillations in astronomy data: revisiting wavelet analysis with coloured and white noise

    Science.gov (United States)

    Xu, Chang

    2017-04-01

    The intrinsic random variability of an astronomical source hampers the detection of possible periodicities that we are interested in. We find that a simple first-order autoregressive [AR(1)] process gives a poor fit to the power decay in the observed spectrum for astrophysical sources and geodetic observations. Thus, appropriate background noise models have to be chosen for significance tests to distinguish real features from the intrinsic variability of the source. Here we recall the wavelet analysis with significance and confidence testing but extend it with the generalized Gauss Markov stochastic model as the null hypothesis, which includes AR(1) and a power law as special cases. We exemplify this discussion with real data, such as sunspot number data, geomagnetic indices, X-ray observations, as well as a Global Positioning System (GPS) position time series.

  8. Menopause: A Life Cycle Transition.

    Science.gov (United States)

    Evarts, Barbara Kess; Baldwin, Cynthia

    1998-01-01

    Family therapists need to address the issue of menopause proactively to be of benefit to couples and families during this transitional period in the family life cycle. Physical, psychological, and psychosocial factors affecting the menopausal woman and her family, and ways to address these issues in counseling are discussed. (Author/EMK)

  9. XMM-Newton detects X-ray 'solar cycle' in distant star

    Science.gov (United States)

    2004-05-01

    The Sun as observed by SOHO hi-res Size hi-res: 708 Kb The Sun as observed by SOHO The Sun as observed by the ESA/NASA SOHO observatory near the minimum of the solar cycle (left) and near its maximum (right). The signs of solar activity near the maximum are clearly seen. New XMM-Newton observations suggest that this behaviour may be typical of stars like the Sun, such as HD 81809 in the constellation Hydra. Solar flare - 4 November 2003 The huge flare produced on 4 November 2003 This image of the Sun, obtained by the ESA/NASA SOHO observatory, shows the powerful X-ray flare that took place on 4 November 2003. The associated coronal mass ejection, coming out of the Sun at a speed of 8.2 million kilometres per hour, hit the Earth several hours later and caused disruptions to telecommunication and power distribution lines. New XMM-Newton observations suggest that this behaviour may be typical of stars like the Sun, such as HD 81809 in the constellation Hydra. Since the time Galileo discovered sunspots, in 1610, astronomers have measured their number, size and location on the disc of the Sun. Sunspots are relatively cooler areas on the Sun that are observed as dark patches. Their number rises and falls with the level of activity of the Sun in a cycle of about 11 years. When the Sun is very active, large-scale phenomena take place, such as the flares and coronal mass ejections observed by the ESA/NASA solar observatory SOHO. These events release a large amount of energy and charged particles that hit the Earth and can cause powerful magnetic storms, affecting radio communications, power distribution lines and even our weather and climate. During the solar cycle, the X-ray emission from the Sun varies by a large amount (about a factor of 100) and is strongest when the cycle is at its peak and the surface of the Sun is covered by the largest number of spots. ESA's X-ray observatory, XMM-Newton, has now shown for the first time that this cyclic X-ray behaviour is common to

  10. Study of Ionospheric Indexes T and MF2 related to R12 for Solar Cycles 19-21

    Science.gov (United States)

    Villanueva, Lucia

    2013-04-01

    Modern worldwide communications are mainly based on satellite systems, remote communication networks, and advanced technologies. The most important space weather "meteorological" events produce negative effects on signal transmissions. Magnetic storm conditions that follow coronal mass ejections are particularly of great importance for radio communication at HF frequencies (3-30 MHz range), because the Ionization increase (or decrease), significantly over (or below), the Average Values. Nowadays new technologies make possible to establish Geophysical Observatories and monitor the sun almost in real time giving information about geomagnetic indices. Space Weather programs have interesting software predictions of foF2 producing maps and plots, every some minutes. The Average Values of the ionospheric parameters mainly depend on the position, hour, season and the phase of the 11-year cycle of the solar activity. Around 1990´s several ionospheric indexes were suggested to better predict the state of the foF2 monthly media, as: IF2, G, T and MF2, based on foF2 data from different latitude ionospheric observatories. They really show better seasonal changes than monthly solar indexes of solar flux F10.7 or the international sunspot numbers Ri. The main purpose of this paper is to present an analogic model for the ionospheric index MF2, to establish the average long term predictions of this index. Changes of phase from one cycle to the other of one component of the model is found to fit the data. The usefulness of this model could be the prediction of the ionospheric normal conditions for one entire solar cycle having just the prediction of the maximum of the next smooth sunspot number R12. In this presentation, comparisons of the Australian T index and and the Mikhailov MF2 index show an hysteresis variation with the solar monthly index Ri, such dependence is quite well represented by a polynomial fit of degree 6 for rising and decaying fases for solar cycles 19, 20 and

  11. EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE

    International Nuclear Information System (INIS)

    Kasper, J. C.; Stevens, M. L.; Korreck, K. E.; Maruca, B. A.; Kiefer, K. K.; Schwadron, N. A.; Lepri, S. T.

    2012-01-01

    The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over solar cycle 23. Observations of the abundance of helium relative to hydrogen (A He ≡ 100 × n He /n H ) by the Wind spacecraft are used to examine the dependence of A He on solar wind speed and solar activity between 1994 and 2010. This work updates an earlier study of A He from 1994 to 2004 to include the recent extreme solar minimum and broadly confirms our previous result that A He in slow wind is strongly correlated with sunspot number, reaching its lowest values in each solar minima. During the last minimum, as sunspot numbers reached their lowest levels in recent history, A He continued to decrease, falling to half the levels observed in slow wind during the previous minimum and, for the first time observed, decreasing even in the fastest solar wind. We have also extended our previous analysis by adding measurements of the mean carbon and oxygen charge states observed with the Advanced Composition Explorer spacecraft since 1998. We find that as solar activity decreased, the mean charge states of oxygen and carbon for solar wind of a given speed also fell, implying that the wind was formed in cooler regions in the corona during the recent solar minimum. The physical processes in the coronal responsible for establishing the mean charge state and speed of the solar wind have evolved with solar activity and time.

  12. On the shape and properties of the global heliosphere over the Solar Cycle with Voyager/LECP ions and Cassini/INCA ENAs

    Science.gov (United States)

    Dialynas, Konstantinos; Krimigis, Stamatios; Mitchell, Donald; Decker, Robert; Roelof, Edmond

    2017-04-01

    Voyager 1 (V1) and Voyager 2 (V2) have crossed the termination shock in 2004 (V1) and 2007(V2) and traversing the Heliosheath (HS) in the upstream (nose) hemisphere, while the Ion and Neutral Camera (INCA) on Cassini enables Energetic Neutral Atom (ENA) images of the celestial sphere that place the local ion measurements by each Voyager in a global context. We present an analysis of 5.2-55 keV ENA global images of the HS and 28-53 keV in-situ ions over an 11-year period (2003-2014) that corresponds to the declining phase of solar cycle 23 (SC23) and onset of SC24. The measurements reveal a coherent decrease and recovery between ENA in the global heliosphere and in-situ ions at V1/V2 during this time period, in overlapping energy bands, establishing that the HS ions are the source of >28 keV ENA. The similarity in the overall appearance of the images throughout the INCA energy range (5.2-55 keV), reveals that the source of ENAs at 5.2 keV ENA and ion variations with the Solar Sunspot Numbers (SSN) and solar wind parameters indicates that the Heliosphere responds promptly, within 2-3 years, to outward propagating solar wind changes in both the nose and anti-nose (tail) directions following the Solar Cycle (SC) phases. A detailed latitudinal examination of the global ENA emissions, verifies that the peak intensities between the nose and anti-nose directions are nearly similar, the power law ENA spectral index (γ) is largely the same near the equator in both the nose and anti-nose directions and displays similar spatial dependence with latitude. The totality of the ENA and in situ ion observations, together with the V1 measurement of a 0.5 nT interstellar magnetic field (ISMF) and recent modeling, suggest a "bubble-shape" heliosphere, i.e with little substantial tail-like feature. These observations are essential in determining the context for the measurements anticipated by the forthcoming IMAP mission.

  13. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    tribpo

    Abstract. Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change signi- ficantly with rising phase of the solar cycle. We also find temporal varia- tions in the rotation rate near the solar ...

  14. Strong Transverse Photosphere Magnetic Fields and Twist in Light Bridge Dividing Delta Sunspot of Active Region 12673

    OpenAIRE

    Wang, Haimin; Yurchyshyn, Vasyl; Liu, Chang; Ahn, Kwangsu; Toriumi, Shin; Cao, Wenda

    2018-01-01

    Solar Active Region (AR) 12673 is the most flare productive AR in the solar cycle 24. It produced four X-class flares including the X9.3 flare on 06 September 2017 and the X8.2 limb event on 10 September. Sun and Norton (2017) reported that this region had an unusual high rate of flux emergence, while Huang et al. (2018) reported that the X9.3 flare had extremely strong white-light flare emissions. Yang at al. (2017) described the detailed morphological evolution of this AR. In this report, w...

  15. The supercontinent cycle

    Energy Technology Data Exchange (ETDEWEB)

    Nance, R.D.; Worsley, T.R.; Moody, J.B.

    1988-07-01

    This paper discusses a new theory of plate tectonics which proposes that Pangaea was only the most recent in a series of supercontinents that have been breaking up and reassembling every 500 million years or so. The cycle, driven by heat percolating up from the mantle, splits continents and drives interrelated processes that shape the earth's geology and climate and play a role in biological evolution. The framework of the supercontinent theory makes it possible to understand the timing of changes in sea level that have taken place in the past 570 million years, and also helps to explain periods of intense mountain building, episodes of glaciation, and changes in the nature of life on the earth.

  16. A theory of the Earth's magnetic field and of sunspots, based on a self-excited dynamo incorporating the Hall effect

    Directory of Open Access Journals (Sweden)

    A. de Paor

    2001-01-01

    Full Text Available A new viewpoint on the generation and maintenance of the Earth's magnetic field is put forward, which integrates self-exciting dynamo theory with the possibility of energy coupling along orthogonal axes provided by the Hall effect. A nonlinear third-order system is derived, with a fourth equation serving as an observer of unspecified geophysical processes which could result in field reversal. Lyapunov analysis proves that chaos is not intrinsic to this system. Relative constancy of one of the variables produces pseudo equilibrium in a second order subsystem and allows for self-excitation of the geomagnetic field. Electromagnetic analysis yields expressions for key parameters. Models for secular variations recorded at London, Palermo and at the Cape of Good Hope over the past four hundred years are offered. Offset of the Earth's magnetic axis from the geographic axis is central to time-varying declination, but its causes have not yet been established. Applicability of the model to the explanation of sunspot activity is outlined. A corroborating experiment published by Peter Barlow in 1831 is appended.

  17. Benefits of cycle stretchout in pressurized water reactor extended-burnup fuel cycles

    International Nuclear Information System (INIS)

    Matzie, R.A.; Leung, D.C.; Liu, Y.; Beekmann, R.W.

    1981-01-01

    Nuclear reactors are inherently capable of operating for a substantial period beyond their nominal end of cycle (EOC) as a result of negative moderator and fuel temperature coefficients and the decrease in xenon poisoning with lower core power levels. This inherent capability can be used to advantage to reduce annual uranium makeup requirements and cycle energy costs by the use of planned EOC stretchout. This paper discusses the fuel utilization efficiency and economics of both the five-batch, extended-burnup cycle and the three-batch, standard-burnup cycle, which can be improved by employing planned EOC (end of cycle) stretchout. 11 refs

  18. An Economic Evaluation of Binary Cycle Geothermal Electricity Production

    National Research Council Canada - National Science Library

    Fitzgerald, Crissie

    2003-01-01

    .... Variables such as well flow rate, geothermal gradient and electricity prices were varied to study their influence on the economic payback period for binary cycle geothermal electricity production...

  19. The Periodic Pyramid

    Science.gov (United States)

    Hennigan, Jennifer N.; Grubbs, W. Tandy

    2013-01-01

    The chemical elements present in the modern periodic table are arranged in terms of atomic numbers and chemical periodicity. Periodicity arises from quantum mechanical limitations on how many electrons can occupy various shells and subshells of an atom. The shell model of the atom predicts that a maximum of 2, 8, 18, and 32 electrons can occupy…

  20. Book Reviews in Periodicals.

    Science.gov (United States)

    Ettelt, Harold J.

    All recent issues of periodicals found which contain indexed book reviews are listed in this compilation from Drake Memorial Library at the New York State University at Brockport. The periodicals are listed by 29 subject headings in this informal guide designed to be used at Drake Library. The number of reviews in the periodical in a recent year…

  1. Essays on economic cycles

    NARCIS (Netherlands)

    Groot, de E.A. (Bert)

    2006-01-01

    Schumpeter’s line of thought of multiple economic cycles is further investigated. The existence of multiple cycles in economic variables is demonstrated. In basic innovations five different cycles are found. Multiple cycle structures are shown in various macro-economic variables from the United

  2. Nuclear power fuel cycle

    International Nuclear Information System (INIS)

    Havelka, S.; Jakesova, L.

    1982-01-01

    Economic problems are discussed of the fuel cycle (cost of the individual parts of the fuel cycle and the share of the fuel cycle in the price of 1 kWh), the technological problems of the fuel cycle (uranium ore mining and processing, uranium isotope enrichment, the manufacture of fuel elements, the building of long-term storage sites for spent fuel, spent fuel reprocessing, liquid and gaseous waste processing), and the ecologic aspects of the fuel cycle. (H.S.)

  3. Technology cycles and technology revolutions

    Energy Technology Data Exchange (ETDEWEB)

    Paganetto, Luigi; Scandizzo, Pasquale Lucio

    2010-09-15

    Technological cycles have been characterized as the basis of long and continuous periods economic growth through sustained changes in total factor productivity. While this hypothesis is in part consistent with several theories of growth, the sheer magnitude and length of the economic revolutions experienced by humankind seems to indicate surmise that more attention should be given to the origin of major technological and economic changes, with reference to one crucial question: role of production and use of energy in economic development.

  4. Solar Cycle variations of ƒoF2 from IGY to 1990

    Directory of Open Access Journals (Sweden)

    M. K. Goel

    Full Text Available Noontime monthly median values of F2-layer critical frequency foF2 (m for some ionospheric stations representing low- and mid-latitudes are examined for their dependence on solar activity for the years 1957 (IGY to 1990. This is the period for which ionospheric data in digital form is available in two CD-ROMs at the World Data Center, Boulder. It is observed that at mid-latitudes, foF2 (m shows nearly a linear relationship with R12 (the 12-month running average of the Zurich sunspot number, though this relation is nonlinear for low-latitudes. These results indicate some departures from the existing information often used in theoretical and applied areas of space research.Key words. Ionosphere (equatorial ionosphere; mid-latitude ionosphere; modelling and forecasting

  5. Proliferation in cycle

    Energy Technology Data Exchange (ETDEWEB)

    Piao Yunsong [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: yspiao@gucas.ac.cn

    2009-06-15

    In the contracting phase with w{approx_equal}0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w{approx_equal}0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

  6. Proliferation in cycle

    International Nuclear Information System (INIS)

    Piao Yunsong

    2009-01-01

    In the contracting phase with w≅0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w≅0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

  7. Painful menstrual periods

    Science.gov (United States)

    Menstruation - painful; Dysmenorrhea; Periods - painful; Cramps - menstrual; Menstrual cramps ... into two groups, depending on the cause: Primary dysmenorrhea Secondary dysmenorrhea Primary dysmenorrhea is menstrual pain that ...

  8. Middle Helladic Period

    DEFF Research Database (Denmark)

    Sarri, Kalliopi

    1999-01-01

    and their quality was improved considerably toward the end of this period. The profound cultural innovations of the Middle Helladic period were initially interpreted as a result of violent population movement and troubles provoked by the coming of the first Indo-European races. However, this matter does no more...... Helladic period is considered as a period of economic and social decline it was the time during which the mainland features merged with the insular influence, that is all the Aegean elements which led to the creation of the Mycenaean civilization were mixed in a creative way....

  9. A periodic table for cancer.

    Science.gov (United States)

    Epstein, Richard J

    2015-01-01

    Cancers exhibit differences in metastatic behavior and drug sensitivity that correlate with certain tumor-specific variables such as differentiation grade, growth rate/extent and molecular regulatory aberrations. In practice, patient management is based on the past results of clinical trials adjusted for these biomarkers. Here, it is proposed that treatment strategies could be fine-tuned upfront simply by quantifying tumorigenic spatial (cell growth) and temporal (genetic stability) control losses, as predicted by genetic defects of cell-cycle-regulatory gatekeeper and genome-stabilizing caretaker tumor suppressor genes, respectively. These differential quantifications of tumor dysfunction may in turn be used to create a tumor-specific 'periodic table' that guides rational formulation of survival-enhancing anticancer treatment strategies.

  10. Association of Supergranule Mean Scales with Solar Cycle Strengths and Total Solar Irradiance

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, Dipankar, E-mail: sudip@iiap.res.in [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

    2017-07-20

    We analyze the long-term behavior of the supergranule scale parameter, in active regions (ARs) and quiet regions (QRs), using the Kodaikanal digitized data archive. This database provides century-long daily full disk observations of the Sun in Ca ii K wavelengths. In this paper, we study the distributions of the supergranular scales, over the whole data duration, which show identical shape in these two regimes. We found that the AR mean scale values are always higher than that of the QR for every solar cycle. The mean scale values are highly correlated with the sunspot number cycle amplitude and also with total solar irradiance (TSI) variations. Such a correlation establishes the cycle-wise mean scale as a potential calibrator for the historical data reconstructions. We also see an upward trend in the mean scales, as has already been reported in TSI. This may provide new input for climate forcing models. These results also give us insight into the different evolutionary scenarios of the supergranules in the presence of strong (AR) and weak (QR) magnetic fields.

  11. Cycling in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Alexis Zander

    2013-01-01

    Full Text Available Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants’ confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

  12. On some periodicity effects

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.

    2015-01-01

    The talk is concerned with the modelling of wave propagation in and vibration of periodic elastic structures. Although analysis of wave-guide properties of infinite periodic structures is a well establish research subject, some issues have not yet been fully addressed in the literature. The aim o...

  13. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  14. Understanding the Evolution of World Business Cycles

    OpenAIRE

    Ayhan Kose; Christopher Otrok; Charles H. Whiteman

    2005-01-01

    This paper studies the changes in world business cycles during 1960-2003. We employ a Bayesian dynamic latent factor model to estimate common and country-specific components in the main macroeconomic aggregates of the Group of Seven (G-7) countries. We then quantify the relative importance of these components in explaining comovement in each observable aggregate over three distinct time periods: the Bretton Woods (BW) period (1960-72), the period of common shocks (1972-86), and the globalizat...

  15. Periods and Nori motives

    CERN Document Server

    Huber, Annette

    2017-01-01

    This book casts the theory of periods of algebraic varieties in the natural setting of Madhav Nori’s abelian category of mixed motives. It develops Nori’s approach to mixed motives from scratch, thereby filling an important gap in the literature, and then explains the connection of mixed motives to periods, including a detailed account of the theory of period numbers in the sense of Kontsevich-Zagier and their structural properties. Period numbers are central to number theory and algebraic geometry, and also play an important role in other fields such as mathematical physics. There are long-standing conjectures about their transcendence properties, best understood in the language of cohomology of algebraic varieties or, more generally, motives. Readers of this book will discover that Nori’s unconditional construction of an abelian category of motives (over fields embeddable into the complex numbers) is particularly well suited for this purpose. Notably, Kontsevich's formal period algebra represents a to...

  16. Periodical cicadas: A minimal automaton model

    Science.gov (United States)

    de O. Cardozo, Giovano; de A. M. M. Silvestre, Daniel; Colato, Alexandre

    2007-08-01

    The Magicicada spp. life cycles with its prime periods and highly synchronized emergence have defied reasonable scientific explanation since its discovery. During the last decade several models and explanations for this phenomenon appeared in the literature along with a great deal of discussion. Despite this considerable effort, there is no final conclusion about this long standing biological problem. Here, we construct a minimal automaton model without predation/parasitism which reproduces some of these aspects. Our results point towards competition between different strains with limited dispersal threshold as the main factor leading to the emergence of prime numbered life cycles.

  17. Life cycle assessment (LCA)

    DEFF Research Database (Denmark)

    Thrane, Mikkel; Schmidt, Jannick Andresen

    2004-01-01

    The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards.......The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards....

  18. Thorium fuel cycle management

    International Nuclear Information System (INIS)

    Zajac, R.; Darilek, P.; Breza, J.; Necas, V.

    2010-01-01

    In this presentation author deals with the thorium fuel cycle management. Description of the thorium fuels and thorium fuel cycle benefits and challenges as well as thorium fuel calculations performed by the computer code HELIOS are presented.

  19. STUDY OF RAPID FORMATION OF A δ SUNSPOT ASSOCIATED WITH THE 2012 JULY 2 C7.4 FLARE USING HIGH-RESOLUTION OBSERVATIONS OF THE NEW SOLAR TELESCOPE

    International Nuclear Information System (INIS)

    Wang Haimin; Liu Chang; Wang Shuo; Deng Na; Xu Yan; Jing Ju; Cao Wenda

    2013-01-01

    Rapid, irreversible changes of magnetic topology and sunspot structure associated with flares have been systematically observed in recent years. The most striking features include the increase of the horizontal field at the polarity inversion line (PIL) and the co-spatial penumbral darkening. A likely explanation of the above phenomenon is the back reaction to the coronal restructuring after eruptions: a coronal mass ejection carries the upward momentum while the downward momentum compresses the field lines near the PIL. Previous studies could only use low-resolution (above 1'') magnetograms and white-light images. Therefore, the changes are mostly observed for X-class flares. Taking advantage of the 0.''1 spatial resolution and 15 s temporal cadence of the New Solar Telescope at the Big Bear Solar Observatory, we report in detail the rapid formation of sunspot penumbra at the PIL associated with the C7.4 flare on 2012 July 2. It is unambiguously shown that the solar granulation pattern evolves to an alternating dark and bright fibril structure, the typical pattern of penumbra. Interestingly, the appearance of such a penumbra creates a new δ sunspot. The penumbral formation is also accompanied by the enhancement of the horizontal field observed using vector magnetograms from the Helioseismic and Magnetic Imager. We explain our observations as being due to the eruption of a flux rope following magnetic cancellation at the PIL. Subsequently, the re-closed arcade fields are pushed down toward the surface to form the new penumbra. NLFFF extrapolation clearly shows both the flux rope close to the surface and the overlying fields

  20. Chords in longest cycles

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2017-01-01

    If a graph G is 3-connected and has minimum degree at least 4, then some longest cycle in G has a chord. If G is 2-connected and cubic, then every longest cycle in G has a chord.......If a graph G is 3-connected and has minimum degree at least 4, then some longest cycle in G has a chord. If G is 2-connected and cubic, then every longest cycle in G has a chord....

  1. Single generation cycles and delayed feedback cycles are not separate phenomena.

    Science.gov (United States)

    Pfaff, T; Brechtel, A; Drossel, B; Guill, C

    2014-12-01

    We study a simple model for generation cycles, which are oscillations with a period of one or a few generation times of the species. The model is formulated in terms of a single delay-differential equation for the population density of an adult stage, with recruitment to the adult stage depending on the intensity of competition during the juvenile phase. This model is a simplified version of a group of models proposed by Gurney and Nisbet, who were the first to distinguish between single-generation cycles and delayed-feedback cycles. According to these authors, the two oscillation types are caused by different mechanisms and have periods in different intervals, which are one to two generation times for single-generation cycles and two to four generation times for delayed-feedback cycles. By abolishing the strict coupling between the maturation time and the time delay between competition and its effect on the population dynamics, we find that single-generation cycles and delayed-feedback cycles occur in the same model version, with a gradual transition between the two as the model parameters are varied over a sufficiently large range. Furthermore, cycle periods are not bounded to lie within single octaves. This implies that a clear distinction between different types of generation cycles is not possible. Cycles of all periods and even chaos can be generated by varying the parameters that determine the time during which individuals from different cohorts compete with each other. This suggests that life-cycle features in the juvenile stage and during the transition to the adult stage are important determinants of the dynamics of density limited populations. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Cell growth and division cycle

    International Nuclear Information System (INIS)

    Darzynkiewicz, Z.

    1986-01-01

    The concept of the cell cycle in its present form was introduced more than three decades ago. Studying incorporation of DNA precursors by autoradiography, these authors observed that DNA synthesis in individual cells was discontinuous and occupied a discrete portion of the cell life (S phase). Mitotic division was seen to occur after a certain period of time following DNA replication. A distinct time interval between mitosis and DNA replication was also apparent. Thus, the cell cycle was subdivided into four consecutive phases, G/sub 1/, S, G/sub 2/, and M. The G/sub 1/ and G/sub 2/ phases represented the ''gaps'' between mitosis and the start of DNA replication, and between the end of DNA replication and the onset of mitosis, respectively. The cell cycle was defined as the interval between the midpoint of mitosis and the midpoint of the subsequent mitosis of the daughter cell(s). The authors' present knowledge on the cell cycle benefited mostly from the development of four different techniques: autoradiography, time-lapse cinematography, cell synchronization and flow cytometry. Of these, autoradiography has been the most extensively used, especially during the past two decades. By providing a means to analyse incorporation of precursors of DNA, RNA or proteins by individual cells and, in combination with various techniques of cell synchronization, autoradiography yielded most of the data fundamental to the current understanding of the cell cycle-related phenomena. Kinetics of cell progression through the cell cycle could be analysed in great detail after development of such sophisticated autoradiographic approaches as measurements of the fraction of labeled mitoses (''FLM curves'') or multiple sequential cell labelling with /sup 3/H- and /sup 14/C-TdR

  3. Denatured fuel cycles

    International Nuclear Information System (INIS)

    Till, C.E.

    1979-01-01

    This paper traces the history of the denatured fuel concept and discusses the characteristics of fuel cycles based on the concept. The proliferation resistance of denatured fuel cycles, the reactor types they involve, and the limitations they place on energy generation potential are discussed. The paper concludes with some remarks on the outlook for such cycles

  4. Life Cycle Management

    DEFF Research Database (Denmark)

    Bey, Niki

    2018-01-01

    This chapter gives an overview of Life Cycle Management (LCM)—a discipline that deals with the managerial tasks related to practicing sustainable development in an organisation . Just as Life Cycle Assessment, LCM advocates the life cycle perspective , and it applies this perspective in decision...

  5. Termination of cycle rewriting

    NARCIS (Netherlands)

    Zantema, H.; König, B.; Bruggink, H.J.S.; Dowek, G.

    2014-01-01

    String rewriting can not only be applied on strings, but also on cycles and even on general graphs. In this paper we investigate termination of string rewriting applied on cycles, shortly denoted as cycle rewriting, which is a strictly stronger requirement than termination on strings. Most

  6. 2D discontinuous piecewise linear map: Emergence of fashion cycles.

    Science.gov (United States)

    Gardini, L; Sushko, I; Matsuyama, K

    2018-05-01

    We consider a discrete-time version of the continuous-time fashion cycle model introduced in Matsuyama, 1992. Its dynamics are defined by a 2D discontinuous piecewise linear map depending on three parameters. In the parameter space of the map periodicity, regions associated with attracting cycles of different periods are organized in the period adding and period incrementing bifurcation structures. The boundaries of all the periodicity regions related to border collision bifurcations are obtained analytically in explicit form. We show the existence of several partially overlapping period incrementing structures, that is, a novelty for the considered class of maps. Moreover, we show that if the time-delay in the discrete time formulation of the model shrinks to zero, the number of period incrementing structures tends to infinity and the dynamics of the discrete time fashion cycle model converges to those of continuous-time fashion cycle model.

  7. Improved nonparametric inference for multiple correlated periodic sequences

    KAUST Repository

    Sun, Ying; Hart, Jeffrey D.; Genton, Marc G.

    2013-01-01

    cross-validation method to the temperature data obtained from multiple ice cores, investigating the periodicity of the El Niño effect. Our methodology is also illustrated by estimating patients' cardiac cycle from different physiological signals

  8. Mean-periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  9. THE SUN'S SMALL-SCALE MAGNETIC ELEMENTS IN SOLAR CYCLE 23

    International Nuclear Information System (INIS)

    Jin, C. L.; Wang, J. X.; Song, Q.; Zhao, H.

    2011-01-01

    With the unique database from the Michelson Doppler Imager on board the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic elements is studied. More than 13 million small-scale magnetic elements are selected, and the following results are found. (1) The quiet regions dominated the Sun's magnetic flux for about 8 years in the 12.25 year duration of cycle 23. They contributed (0.94-1.44) x10 23 Mx flux to the Sun from the solar minimum to maximum. The monthly average magnetic flux of the quiet regions is 1.12 times that of the active regions in the cycle. (2) The ratio of quiet region flux to that of the total Sun equally characterizes the course of a solar cycle. The 6 month running average flux ratio of the quiet regions was larger than 90.0% for 28 continuous months from July 2007 to October 2009, which very well characterizes the grand solar minima of cycles 23-24. (3) From the small to the large end of the flux spectrum, the variations of numbers and total flux of the network elements show no correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements, covering the flux of (2.9-32.0)x10 18 Mx, occupy 77.2% of the total element number and 37.4% of the quiet-Sun flux. These results provide insight into the reason for anti-correlations of small-scale magnetic activity during the solar cycle.

  10. Finnish and Swedish business cycles in a global context

    DEFF Research Database (Denmark)

    Bergman, Ulf Michael

    2008-01-01

    This paper evaluates the decisions made by the Finnish government to join EMU and the Swedish government not to join EMU in the early 1990s. Focusing on the characteristics of business cycles during the postwar period, we find that output fluctuations in Sweden and Finland are correlated to two...... measures of the international business cycle, a European and a non-European cycle. The Finnish cycle has become more synchronized to the European cycle but less synchronized to the non-EU cycle after 1999. For Sweden we find the opposite result. The decision by the Finnish government to join EMU...

  11. Painful periods (dysmenorrhea) (image)

    Science.gov (United States)

    Primary dysmenorrhea is a normal cramping of the lower abdomen caused by hormone-induced uterine contractions before the period. Secondary dysmenorrhea may be caused by abnormal conditions such as ...

  12. Vaginal bleeding between periods

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003156.htm Vaginal bleeding between periods To use the sharing features ... this page, please enable JavaScript. This article discusses vaginal bleeding that occurs between a woman's monthly menstrual ...

  13. Super periodic potential

    Science.gov (United States)

    Hasan, Mohammd; Mandal, Bhabani Prasad

    2018-04-01

    In this paper we introduce the concept of super periodic potential (SPP) of arbitrary order n, n ∈I+, in one dimension. General theory of wave propagation through SPP of order n is presented and the reflection and transmission coefficients are derived in their closed analytical form by transfer matrix formulation. We present scattering features of super periodic rectangular potential and super periodic delta potential as special cases of SPP. It is found that the symmetric self-similarity is the special case of super periodicity. Thus by identifying a symmetric fractal potential as special cases of SPP, one can obtain the tunnelling amplitude for a particle from such fractal potential. By using the formalism of SPP we obtain the close form expression of tunnelling amplitude of a particle for general Cantor and Smith-Volterra-Cantor potentials.

  14. Establishing contract periods

    International Nuclear Information System (INIS)

    Huffman, F.C.

    1978-01-01

    The lead time for executing the Adjustable Fixed-Commitment (AFC) contract and exceptions which may be considered are discussed. The initial delivery period is also discussed. Delays, deferrals, and schedule adjustment charges are finally considered

  15. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  16. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  17. Viral infection model with periodic lytic immune response

    International Nuclear Information System (INIS)

    Wang Kaifa; Wang Wendi; Liu Xianning

    2006-01-01

    Dynamical behavior and bifurcation structure of a viral infection model are studied under the assumption that the lytic immune response is periodic in time. The infection-free equilibrium is globally asymptotically stable when the basic reproductive ratio of virus is less than or equal to one. There is a non-constant periodic solution if the basic reproductive ratio of the virus is greater than one. It is found that period doubling bifurcations occur as the amplitude of lytic component is increased. For intermediate birth rates, the period triplication occurs and then period doubling cascades proceed gradually toward chaotic cycles. For large birth rate, the period doubling cascade proceeds gradually toward chaotic cycles without the period triplication, and the inverse period doubling can be observed. These results can be used to explain the oscillation behaviors of virus population, which was observed in chronic HBV or HCV carriers

  18. Supersymmetrically transformed periodic potentials

    OpenAIRE

    C, David J. Fernandez

    2003-01-01

    The higher order supersymmetric partners of a stationary periodic potential are studied. The transformation functions associated to the band edges do not change the spectral structure. However, when the transformation is implemented for factorization energies inside of the forbidden bands, the final potential will have again the initial band structure but it can have bound states encrusted into the gaps, giving place to localized periodicity defects.

  19. Thyrotoxic periodic paralysis

    OpenAIRE

    Rojith Karandode Balakrishnan; Suresh Rama Chandran; Geetha Thirumalnesan; Nedumaran Doraisamy

    2011-01-01

    This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recove...

  20. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    ) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...