Instantaneous Phase and Amplitude Correlation in the Solar Cycle     

Mininni  Pablo D.  Gomez  Daniel O.  Mindlin  Gabriel B. 《Solar physics》2002,208(1):167-179

In the present study we address the issue of discerning between deterministic and stochastic paradigms in order to understand the behavior of the solar cycle. To this end we show the degree of correlation between the instantaneous amplitude and frequency in the sunspot number time series by the use of the Gabor analytic signal. We compare this correlation with those arising from two theoretical models: (a) the Barnes model of widespread use in the literature and (b) a spatial truncation of the MHD equations. We show that comparisons between the correlation observed in the sunspot time series with those arising from theoretical models can be used to refute one of the models.  相似文献   

ETHNIC DIFFERENCES IN MIGRATION PATTERNS—DISPARITIES AMONG ARABS AND JEWS IN THE PERIPHERAL REGIONS OF ISRAEL*     

Gabriel Lipshitz 《The Professional geographer》1991,43(4):445-456

Studies of migration patterns in national peripheries of countries do not distinguish between different population groups in these regions. The present study examines spatial patterns of Arab and Jewish populations in Israel's national periphery. The migration trends of Arabs and Jews in the northern national periphery (the Galilee) are compared with those of the southern national periphery (the Negev). The Arab and Jewish populations within these areas show different spatial patterns of migration: in both the northern and the southern peripheries, Jews tend to migrate from the periphery to the core, while Arabs tend to migrate within the periphery. These differences increase the ratio of Arabs to Jews in both regions. The findings suggest that researchers should examine subregions and subgroups when studying migration patterns.  相似文献   

Separation of gamma and hadron initiated air showers with energies between 20 and 500 TeV     

F. Arqueros  A. Karle  E. Lorenz  S. Martinez  R. Plaga  M. Rozanska 《Astroparticle Physics》1996,4(4):309-332

The discrimination between air showers initiated by γ rays and by hadrons is one of the fundamental problems in experimental cosmic-ray physics. The physics of this ‘γ/hadron separation’ is discussed in this paper. We restrict ourselves to the energy range from about 20 to 500 TeV, and take only the information contained in the lateral Čerenkov light distribution and the number of electrons at the detector level into consideration. An understanding of the differences between air showers generated by γ rays and those due to hadrons leads us to formulate suitable observables for the separation process. Angle integrating Čerenkov arrays (AICA) offer a promising new approach to ground-based γ-ray astronomy in the energy region from about 20 to 500 TeV. In order to establish this technique, an efficient suppression of the overwhelming hadronic background radiation is required. As an example for our general discussion, we present one method for γ/hadron separation in AICAs called ‘LES’. It is based on the simultaneous determination of the shower size and some characteristic parameters of the lateral distribution of the Čerenkov light. The potential inherent within this technique is demonstrated in quantitative detail for the existing ‘AIROBICC’ AICA. We also propose an objective measure of the intrinsic sensitivity of a detection scheme in ground-based γ-ray astronomy, the ‘reduced quality factor’. It is shown that AICAs may reach a sensitivity to γ-ray point sources in the high VHE range similar to that of the Čerenkov-telescope imaging technique in the low VHE region.  相似文献   

Modeling spatial landslide susceptibility in volcanic terrains through continuous neighborhood spatial analysis and multiple logistic regression in La Ciénega watershed,Nevado de Toluca,Mexico     

Castro-Miguel  Rutilio  Legorreta-Paulín  Gabriel  Bonifaz-Alfonzo  Roberto  Aceves-Quesada  José Fernando  Castillo-Santiago  Miguel Ángel 《Natural Hazards》2022,113(1):767-788

Natural Hazards - Little study has been done on the effect of the pixel neighborhood information when modeling landslide susceptibility using multiple logistic regression (MLR). The present...  相似文献   

Topo-Iberia project: CGPS crustal velocity field in the Iberian Peninsula and Morocco     

J. Garate  J. Martin-Davila  G. Khazaradze  A. Echeverria  E. Asensio  A. J. Gil  M. C. de Lacy  J. A. Armenteros  A. M. Ruiz  J. Gallastegui  F. Alvarez-Lobato  C. Ayala  G. Rodríguez-Caderot  J. Galindo-Zaldívar  A. Rimi  M. Harnafi 《GPS Solutions》2015,19(2):287-295

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Understanding connected surface-water/groundwater systems using Fourier analysis of daily and sub-daily head fluctuations     

R. I. Acworth  Gabriel C. Rau  Andrew M. McCallum  Martin S. Andersen  Mark O. Cuthbert 《Hydrogeology Journal》2015,23(1):143-159

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High-order finite difference modeling of tsunami generation in a compressible ocean from offshore earthquakes   总被引：1，自引：0，他引：1  

Gabriel C. Lotto  Eric M. Dunham 《Computational Geosciences》2015,19(2):327-340

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Dynamics of an isolated,viscoelastic, self-gravitating body     

C. Ragazzo  L. S. Ruiz 《Celestial Mechanics and Dynamical Astronomy》2015,122(4):303-332

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On the variability of seasonal temperature in southern South America     

Ana Laura Berman  Gabriel Silvestri  Rosa Compagnucci 《Climate Dynamics》2013,40(7-8):1863-1878

The aim of this paper is to investigate different aspects of the seasonal-to-interannual temperature variability in Eastern Patagonia, the southernmost area of South America, east of the Andes Cordillera. Homogenous regions of seasonal variability and the atmospheric circulation patterns associated with warm and cold conditions in each of them are described in this study. Relationships between temperature in Eastern Patagonia and that registered in other areas of southern South America are also addressed. Results show that the northern and southern areas of Eastern Patagonia have different temperature variability in summer and autumn whereas the temperature variability tends to be more homogeneous within the region during winter and spring. Warm (cold) conditions in the northern areas are associated with reinforced (weakened) westerlies in summer, winter and spring whereas northerly (southerly) advections of warm (cold) air toward the region produce such conditions in autumn. Temperature in the southern portion of Eastern Patagonia is affected by anticyclonic (cyclonic) anomalies that enhance (reduce) the incoming solar radiation and induce reinforced (weakened) westerlies promoting warm (cold) conditions in the region. Furthermore, cyclonic (anticyclonic) anomalies at subpolar latitudes hinder (favor) outbreaks of cold air increasing (decreasing) the temperature over areas of Eastern Patagonia. The circulation anomalies associated with warm (cold) conditions in Eastern Patagonia also promote cold (warm) conditions over areas of northern Argentina, Paraguay and southern Brazil. Consequently, a dipole of temperature is detected in southern South America with centers of opposite sign over these regions.  相似文献   

Cratering and modification of wet‐target craters: Projectile impact experiments and field observations of the Lockne marine‐target crater (Sweden)     

Jens Orm  Maurits Lindstrm  Alain Lepinette  Jesús Martinez‐Frias  Enrique Diaz‐Martinez 《Meteoritics & planetary science》2006,41(10):1605-1612

Abstract— Marine impacts are one category of crater formation in volatile targets. At target water depths exceeding the diameter of the impactor, the zones of vaporization, melting, and excavation of the standard land‐target cratering model develop partially or entirely in the water column. The part of the crater that has a potential of being preserved (seafloor crater) may to a great extent be formed by material emplacement and excavation processes that are very different from land‐target craters. These processes include a high‐energy, water‐jet‐driven excavation flow. At greater water depths, the difference in strength of the target layers causes a concentric crater to evolve. The crater consists of a wide water cavity with a shallow excavation flow along the seabed surrounding a nested, deeper crater in the basement. The modification of the crater is likewise influenced by the water through its forceful resurge to fill the cavity in the water mass and the seafloor. The resurge flow is strongly erosive and incorporates both ejecta and rip‐up material from the seabed surrounding the excavated crater. A combination of field observations and impact experiments has helped us analyze the processes affecting the zone between the basement crater and the maximum extent of the water cavity. The resurge erosion is facilitated by fragmentation of the upper parts of the solid target caused by a) spallation and b) vibrations from the shallow excavation flow and, subsequently, c) the vertical collapse of the water cavity rim wall. In addition, poorly consolidated and saturated sediments may collapse extensively, possibly aided by a violent expansion of the pore water volume when it turns into a spray during passage of the rarefaction wave. This process may also occur at impacts into water‐saturated targets without an upper layer of seawater present. Our results have implications for impacts on both Earth and Mars, and possibly anywhere in the solar system where volatiles exist/have existed in the upper part of the target.  相似文献