Compton Gamma Ray Observatory/BATSE observations of energetic electrons scattered by cyclotron resonance with waves from powerful VLF transmitters

To obtain a better understanding of the wave-particle mechanisms responsible for the loss of electrons from the radiation belts, energetic electron data from the Burst and Transient Source Experiment (BATSE) on the NASA's Compton Gamma Ray Observatory (GRO) was studied. Powerful ground-based VLF transmitters resonantly scatter electrons from the inner radiation belt onto trajectories from which they precipitate into the atmosphere as they drift eastward. 563 instances in which the satellite traversed a cloud of energetic electrons which had been scattered into quasi-trapped trajectories were identified. From the longitude distribution, it was concluded that waves from the VLF transmitter NWC at 114 deg E are the origin of 257 of the events, and waves from UMSat 44 deg E related to 45 more. In another 177 cases the electrons had drifted from the longitude of these transmitters to a location in the western hemisphere. The previously reported seasonal variation in the frequency of occurrence of cyclotron resonance interaction is confirmed with the continuous coverage provided by GRO. The frequency of occurrence of the cyclotron resonance interactions is largest before sunrise, which we attribute to the diurnal variations in the transmission VLF waves through the ionosphere. For the first time, unique very narrow sheets of electrons occurring in the aftermath of a large geomagnetic storm are reported

Detection of a MicroRNA Signal in an In Vivo Expression Set of mRNAs

Background. microRNAs (miRNAs) are approximately 21 nucleotide non-coding transcripts capable of regulating gene expression. The most widely studied mechanism of regulation involves binding of a miRNA to the target mRNA. As a result, translation of the target mRNA is inhibited and the mRNA may be destabilized. The inhibitory effects of miRNAs have been linked to diverse cellular processes including malignant proliferation, apoptosis, development, differentiation, and metabolic processes. We asked whether endogenous fluctuations in a set of mRNA and miRNA profiles contain correlated changes that are statistically distinguishable from the many other fluctuations in the data set. Methodology/Principal Findings. RNA was extracted from 12 human primary brain tumor biopsies. These samples were used to determine genome-wide mRN

Satellite Experiments Simultaneous with Antarctic Measurements (SESAME)

Satellite Experiments Simultaneous with Antarctic Measurements (SESAME) is one of the four ground-based programmes within the NASA/ISAS Global Geospace Science (GGS) mission, itself part of the International Solar-Terrestrial Physics (ISTP) programme. The scientific objectives of SESAME are carefully selected to make an invaluable contribution to the GGS mission by capitalising on the unique geophysical advantages of Antarctica for geospace research. These arise mainly from the large displacement of the geographic and geomagnetic poles. Specifically, SESAME is designed to study the ionospheric effects of merging at the magnetopause, reconnection in the geomagnetic tail and its relationship to substorms, mapping of significant geospace boundaries to ionospheric altitudes, plasma wave generation and propagation at high latitudes, and ionosphere-thermosphere interactions. The experimental programme is centred at Halley (76° S, 27° W) but also utilises automatic geophysical observatories located poleward of Halley. The suite of instruments provides an excellent image of the inner boundary of geospace and thus is complementary to the GGS spacecraft measurements. The data products that will be supplied askey parameters to the GGS experimenters on a routine basis are described. A brief review of previous results is presented, and some of the significant scientific questions to be addressed using the combination of ground-based and space-based observations are discussed