The far-reaching gravitational force—in the approximation of Newton’s law of gravitation—is described by a heuristic model with hypothetical massless particles propagating at the speed of light in vacuum and transferring momentum and energy between physical entities through interactions on a local basis. The model has some similarities with the impact theory presented by Nicolas Fatio de Duillier to the Royal Society in 1690. Objections raised against this idea are dispelled by invoking the Special Theory of Relativity, considering non-local interactions, and replacing the shielding concept by a secular mass increase of massive bodies. Some consequences and applications of the model are discussed. 相似文献
On 21 November 2004, about 1000 barrels of crude oil were accidentally released from the Terra Nova FPSO (floating production, storage and offloading) onto the Grand Banks, approximately 340 km east-southeast of St. John's, Newfoundland. We estimated the number of vulnerable seabirds (murres (Uria spp.) and dovekies (Alle alle)) at risk from this incident by multiplying observed densities of seabirds with the total area covered by the slick, estimated at 793 km(2). A mean density of 3.46 murres/km(2) and 1.07 dovekies/km(2) on the sea surface was recorded during vessel-based surveys on 28 and 29 November 2004, with a mean density of 6.90 murres/km(2) and 13.43 dovekies/km(2) combining those on the sea and in flight. We calculated a mean of 9858 murres and dovekies were at risk of being oiled, with estimates ranging from 3593 to 16,122 depending on what portion of birds in flight were assumed to be at risk. A mortality model based on spill volume was derived independently of the risk model, and estimated that 4688 (CI 95%: 1905-12,480) birds were killed during this incident. A low mortality estimate based strictly on spill volume would be expected for this incident, which occurred in an area of relatively high seabird densities. Given that the risk and mortality estimates are statistically indistinguishable, we estimate that on the order of 10,000 birds were killed by the Terra Nova spill. 相似文献
A54 Cosmic Ray Acceleration in Galactic Wind Shocks A71 Detection of Ultra‐High Energy Cosmic Rays and Neutrinos with LOFAR A80 Status of the gravitational‐wave detector GEO600 A87 Recent Results and Future of the MAGIC gamma‐ray telescope A92 Cosmic ray detection with the radio technique A93 Cosmic Ray Physics with IceCube A94 The resonance‐like gamma‐ray absorption processes for use in astrophysics A97 Geometry reconstruction of air shower fluorescence detectors revisited A102 Supermassive Binary Black Holes & Radio Jets A108 Muonic Component of Air Showers Measured by KASCADE‐Grande A110 Towards new frontiers: observation of photons with energies above 1018 eV A112 The IceCube Neutrino Telescope A114 The ground‐based gamma‐ray observatory CTA A116 IceCube: Recent Results and Prospects A117 Particle Physics with AMANDA and IceCube A118 Altitude dependence of fluorescence light emission by extensive air showers A120 Neutrino‐induced cascades in AMANDA & IceCube A122 Enhancement Telescopes for the Pierre Auger Southern Observatory in Argentina A123 Proton spectra from relativistic shock environments in AGN and GRBs A124 The Baikal Neutrino Telescope – Physics Results A127 Searches for point‐like sources of cosmic neutrinos with IceCube A128 The MAGIC/IceCube Target of Opportunity Programtest run A131 Supernova detection with IceCube: from low to high energy neutrinos A132 Measurement of the UHECR energy spectrum from hybrid data of the Pierre Auger Observatory A133 Extension of IceCube at Lower Energy: the Use of AMANDA as Nested Array and the Future Prospectives A135 Searching for neutrinos with the Pierre Auger Observatory A138 Search for Transient Emission of Neutrinos in IceCube A140 Acoustic Neutrino Detection in Antarctic Ice A159 AMANDA limits on the diffuse muon‐neutrino flux: physics implications A164 Investigation of the Radio Emission of Cosmic Ray Air Showers with LOPES A168 The Northern Site of the Pierre Auger Observatory A170 Shower reconstruction and size spectra with KASCADE‐Grande data A171 Neutrinos from Gamma Ray Bursts: predictions and limits from AMANDA‐II data A172 Simulation study of shower profiles from ultra‐high energy cosmic rays A174 Upper limit to the photon fraction in cosmic rays above 1019 eV from the Pierre Auger Observatory A176 Astrophysics at MeV energies A180 Study of the Cosmic Ray Composition above 0.4 EeV using the Longitudinal Profiles of Showers observed at the Pierre Auger Observatory A185 Backgrounds for UHE horizontal neutrino showers A186 The Front‐End Cards of the Pierre Auger Surface Detectors: Test Results and Performance in the Field A187 Monte Carlo Studies for MAGIC‐II A194 Measuring the proton‐air cross section from logitudinal air shower profiles A195 The UHECR energy spectrummeasured at the Pierre Auger Observatory A203 Highlights of Observations of Galactic Sources with the MAGIC telescope A207 Adesign study for a 12.5 m ∅︁ Imaging Air Cherenkov Telescope for ground‐based γ ‐ray astronomy A210 The Future of Long‐Wavelengths Radio‐Astronomy in Germany: LOFAR and GLOW A211 Online Monitoring of the Pierre Auger Observatory A216 OPTIMA‐Burst – Catching GRB Afterglows (and other Transients) with High Time Resolution A227 JEM‐EUSO mission A232 Rapid Variations in AGN: Clues on Particle Accelerators A235 Systematic search forVHEgamma‐ray emission from X‐ray bright high‐frequency peaked BL Lac objects A237 Prospects for GeV Astronomy in the Era of GLAST A241 Improvements of the energy reconstruction for the MAGIC telescope by means of analysis and Monte Carlo techniques A265 Discovery of VHE γ ‐rays from BL Lacertae with the MAGIC telescope A266 Results of two observation cycles of LS I+61°303 with the MAGIC telescope A267 Wide Range Multifrequency Observations of Northern TeV Blazars A269 Diffusive and convective cosmic ray transport in elliptical galaxies 相似文献
The EUV line emission and relative line-of-sight velocity in the transition region between the chromosphere and corona of 36 sunspot regions are investigated, based on observations with the Coronal Diagnostic Spectrometer – CDS and the Solar Ultraviolet Measurements of Emitted Radiation – SUMER on the Solar and Heliospheric Observatory – SOHO. The most prominent features in the transition-region intensity maps are the sunspot plumes. In the temperature range between log T=5.2 and log T=5.6 we find that 29 of the 36 sunspots contain one or two sunspot plumes. The relative line-of-sight velocity in sunspot plumes is high and directed into the Sun in the transition region, for 19 of the sunspots the maximum velocity exceeds 25 km s?1. The velocity increases with increasing temperature, reaches a maximum close to log T=5.5 and then decreases abruptly.
Attention is given to the properties of oscillations with a period of 3 min in the sunspot transition region, based on observations of six sunspots. Comparing loci with the same phase we find that the 3-min oscillations affect the entire umbral transition region and part of the penumbral transition region. Above the umbra the observed relation between the oscillations in peak line intensity and line-of-sight velocity is compatible with the hypothesis that the oscillations are caused by upward-propagating acoustic waves. Information about intensity oscillations in the low corona is obtained from observations of one sunspot in the 171 Å channel with the Transition Region And Coronal Explorer – TRACE. We conclude that we observe the 3-min sunspot oscillations in the chromosphere, the transition region and the low corona. The oscillations are observable over a wider temperature range than the sunspot plumes, and show a different spatial distribution than that of the plumes.
An airborne gravity campaign was carried out at the Dome-C survey area in East Antarctica between the 17th and 22nd of January 2013, in order to provide data for an experiment to validate GOCE satellite gravity gradients. After typical filtering for airborne gravity data, the cross-over error statistics for the few crossing points are 11.3 mGal root mean square (rms) error, corresponding to an rms line error of 8.0 mGal. This number is relatively large due to the rough flight conditions, short lines and field handling procedures used. Comparison of the airborne gravity data with GOCE RL4 spherical harmonic models confirmed the quality of the airborne data and that they contain more high-frequency signal than the global models. First, the airborne gravity data were upward continued to GOCE altitude to predict gravity gradients in the local North-East-Up reference frame. In this step, the least squares collocation using the ITGGRACE2010S field to degree and order 90 as reference field, which is subtracted from both the airborne gravity and GOCE gravity gradients, was applied. Then, the predicted gradients were rotated to the gradiometer reference frame using level 1 attitude quaternion data. The validation with the airborne gravity data was limited to the accurate gradient anomalies (TXX, TYY, TZZ and TXZ) where the long-wavelength information of the GOCE gradients has been replaced with GOCO03s signal to avoid contamination with GOCE gradient errors at these wavelengths. The comparison shows standard deviations between the predicted and GOCE gradient anomalies TXX, TYY, TZZ and TXZ of 9.9, 11.5, 11.6 and 10.4 mE, respectively. A more precise airborne gravity survey of the southern polar gap which is not observed by GOCE would thus provide gradient predictions at a better accuracy, complementing the GOCE coverage in this region. 相似文献
In an earlier study, we defined an “unexpected wave” as, for example, a wave twice as high as any of the preceding 30 waves. Here we extend earlier deep water simulations to allow for the greater crest enhancement in water of finite depth and find that the predicted frequency of unexpected waves increases significantly. We also analyze data obtained by wave buoys off the east and west coasts of Canada. In both deep and intermediate depth water, the occurrence of unexpected waves is in reasonable accord with our simulations, supporting our assumption of random superposition of waves though with local crest enhancement by the non-resonant second harmonic. 相似文献