Continuum Contributions to the SDO/AIA Passbands During Solar Flares

Data from the Multiple EUV Grating Spectrograph (MEGS-A) component of the Extreme Ultraviolet Experiment (EVE) onboard the Solar Dynamics Observatory (SDO) were used to quantify the contribution of continuum emission to each of the EUV channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during an X-class solar flare that occurred on 2011 February 15. Both the pre-flare subtracted EVE spectra and fits to the associated free-free continuum were convolved with the AIA response functions of the seven EUV passbands at 10 s cadence throughout the course of the flare. It was found that 10-25% of the total emission in the 94A, 131A, 193A, and 335A passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171A channel, while the continuum contribution to the 304A channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211A channel was found to be due to free-free emission around the peak of the flare, while an additional 20% was due to the recombination continuum of He II. The analysis was extended to a number of M- and X-class flares and it was found that the level of free-free emission contributing to the 171A and 211A passbands increased with increasing GOES class. These results suggest that the amount of continuum emission that contributes to AIA observations during flares is more significant than that stated in previous studies which used synthetic, rather than observed, spectra. These findings highlight the importance of spectroscopic observations carried out in conjunction with those from imaging instruments so that the data are interpreted correctly.Comment: 9 pages, 6 figures, 1 tabl

Documentation for the spatial analysis system (SPAN) for resource use by animals

Nearest-neighbor analyses have been used with mapped data f or tests of spatial dispersion and association i n plant and animal ecology. This paper full describes a computer software package developed to use Monte Carlo trials instead of chi-squared distributions for assigning probabilities to observed values of nearest neighbor statistics. The program can factor-out the unique geometry of resources in a sample plot,which can affect locations of animals, thus testing for direct patterns among the animals independent of their resource patterns. The Kappa statistic for association is a1 o calculated a1though its application has met with limited success. A users manual and the Fortran program language is included. (80pp.

Paramagnon-induced dispersion anomalies in the cuprates

We report the self-energy associated with RPA magnetic susceptibility in the hole-doped Bi_2Sr_2CuO_6 (Bi2201) and the electron-doped Nd_{2-x}Ce_xCuO_4 (NCCO) in the overdoped regime within the framework of a one-band Hubbard model. Strong weight is found in the magnetic spectrum around (pi, 0) at about 360 meV in Bi2201 and 640 meV in NCCO, which yields dispersion anomalies in accord with the recently observed `waterfall' effects in the cuprates.Comment: Submitted to PRL, Dec. 21, 2006; 4 eps figures, revte

Roy Wilkins as a journalist

"This study is primarily concerned with an observation of Wilkins' journalistic image as reflected in his newspaper, magazine and syndicated columns concerning the racial and economic problems of the Negro American. A detailed observation is made of his editorial endeavors in each of the areas. It shows the concern Wilkins holds for the practical application of racial/community service in journalism, and it shows how he has become a guide to America's black newsmen." [From p. 14 "PURPOSE OF THIS STUDY"

A Quarrell sett out in metre : Towards a New Edition of Scottish Reformation Satirical Literature

Discusses the issues of definition and genre in preparing a new edition for the Scottish Text Society of satirical poems (and prose) from the Scottish Reformation period, and also comments on decisions about editing Scottish Renaissance manuscript poetry

Uranium Mining on the Navajo Indian Reservation: An Environmental Examination of the Process and Impact

Uranium mining on the Navajo Reservation created an environmental justice disaster which has strangely helped bring the Navajo Nation to achieve considerable self-determination within the United States. The United States’ need for uranium to fuel the nuclear weapons and energy program brought the Atomic Energy Commission to establish an extensive mining operation on Southwestern edge of the Colorado Plateau. Many of mines established were on or near the Navajo Indian reservation. The Navajo Nation received little share in the profits due to poorly constructed lease and royalty contracts. What is more, most mines employed almost entirely Navajo men who were never told of the known health hazards from radiation expose. The Navajo people were desperate to work, the AEC was driven to produce uranium as quickly as possible, and the mining companies working for the AEC wanted the largest possible profits. Despite pressure from the Public Health Service (PHS), who had been gathering data revealing dangerous levels of radiation exposure, no regulations were imposed for nearly thirty years. By this time, health problems predicted by PHS were coming true and uranium workers were dying of cancers and lung diseases. The horror of this spreading sickness spurred the Navajo people to act and fight for justice. After a long battle they finally achieved acknowledgment that the U.S. government had negligently failed to protect the health of uranium miners. The testimonies of the miners, their widows and their families tell heartbreaking tales of the anger, frustration and sadness the Navajo people have experienced because they felt they were betrayed by the government, lost family members and were left to live in toxic environments. However, fueled by this range of emotions the Navajo Nation has changed significantly. The Tribal Council has asserted authority in the creation of new leases and regulations to ensure the Navajo people benefit from the extraction of their natural resources. Individuals worked to unite communities in the fight for justice and respect. Navajo government organizations such as the office of Abandoned Mine Lands have even set new standards for reclamation and community redevelopment projects. While circumstances at the start of uranium mining were perfect to enable the exploitation of the Navajo people, new circumstances created by changes in National policy and Navajo initiates have made the Navajo Nation a more wary and self-determined nation. Unfortunately, this long awaited goal and respected sovereignty has come at a very high price

Signatures of modulated pair interaction in cuprate superconductors

Recent low-temperature scanning tunnelling spectroscopy experiments on the surface of BSCCO-2212 have revealed a strong positive correlation between the position of localized resonances at -960 meV identified with interstitial oxygen dopants and the size of the local spectral gap. We review efforts to understand these correlations within a model where the dopants modulate the pair interaction on an atomic scale. We provide further evidence for this model by comparing the correlations between the dopants and the local density of states with experimental results.Comment: 4 pages, 2 figures, submitted to M2S-HTSC VIII, Dresden 200

Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

Hydrogen-oxygen solid polymer electrolyte (SPE) fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. These solid electrolyte devices have been under continuous development for over 30 years. This experience has resulted in a demonstrated ten-year SPE cell life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluoride loss rates and average expected ultimate cell life. This relationship is shown. Several features have been introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability has been demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density