Physics in Ultra-strong Magnetic Fields

In magnetic fields stronger than B_Q = 4.4 X 10^13 Gauss, an electron's Landau excitation energy exceeds its rest energy. I review the physics of this strange regime and some of its implications for the crusts and magneto- spheres of neutron stars. In particular, I describe how ultra-strong fields >> render the vacuum birefringent and capable of distorting and magnifying images ("magnetic lensing"); >> change the self-energy of electrons: as B increases they are first slightly lighter than $m_e$, then slightly heavier; >> cause photons to rapidly split and merge with each other; >> distort atoms into long, thin cylinders and molecules into strong, polymer-like chains; >> enhance the pair density in thermal pair-photon gases; >> strongly suppress photon-electron scattering, and >> drive the vacuum itself unstable, at extremely large B. In a concluding section, I discuss recent observations of the spindown histories of soft gamma repeaters and anomalous X-ray pulsars. The magnetar model gives a promising framework for understanding these data.Comment: Review talk given at Fifth Huntsville Gamma-Ray Burst Symposium. 12 pages with 5 eps figure

Gamma-Ray Bursts from Extragalactic Magnetar Flares

The prototype for events that we call MFs - "March Fifth" events or "Magnetar Flares" - was observed on March 5, 1979. There is evidence that MFs are powered by catastrophic magnetic instabilities in ultramagnetized neutron stars. These events begin with brief (~ 0.1 - 1 s), intense, hard spikes of gamma rays followed by long (~ 100 s) softer tails of hard X-rays, modulated on the stellar rotation period. Prototypical MFs could have been detected by BATSE out to ~ 13 Mpc, nearly reaching the Virgo cluster. The likely number of isotropic, standard-candle MFs detected by the BATSE experiment is ~ 12. Bayes' Theorem implies that there is a 99% chance for at least 1 MF in the BATSE catalog, and a 16% chance for more than 20. These short-duration, fast-rising gamma-ray bursts could in principle be identified by their positional coincidences with nearby galaxies. The ensuing soft tail emission would not have been detected by BATSE for sources more distant than M31. It is possible that MFs also emit an intense, hard, BEAMED component during the intial spike phase. If this beamed component has opening angle ~ 8 degrees and peak luminosity comparable to the power of the isotropic component, then BATSE would detect such beamed sources out to redshift z ~ 0.1, at a full-sky rate of ~ 100 yr^-1. We speculate that such beamed MFs could account for the short, hard Class II gamma-ray bursts in the BATSE catalog, or some significant subset of them. If true, then Class II GRBs positions would correlate with the positions of galaxies and galaxy clusters within ~ 350 Mpc.Comment: 6 pages; to appear in Proceedings of 20th Texas Symposium on Relativistic Astrophysics, eds. H Martel & J.C. Wheeler (AIP Press

The contribution of Hermann Cremer (1834-1903) to theological hermeneutics

During the last century and a half the Holy Scriptures have been subjected to an immense amount of painstaking scientific research. A vast body of new knowledge has come to light as a result, and the historico- critical method reigns supreme in the realm of biblical interpretation. Archaeology, the history of religions, textual, literary, and form criticism, all played a part in the movement toward a more scientific understanding of the biblical writings. Yet for some time past there has been a growing feeling in many quarters that all this is not enough. Hermeneutics has become a fashionable word once more in the theological vocabulary.The theological revival which is spreading through the churches has brought with it a renewed concern to discover the biblical basis for the unity of the Church. Biblical studies are tending to delve more and more into the meaning of the theological terminology of Scripture itself. There is every indication that some of the deepest problems of biblical theology can be resolved by means of a semantic investigation of key words in both the Old and New Testaments. It is in this connection that the labors of the German theologian Hermann Cremer (18341903) take on fresh interest and significance. I shall endeavor to show how his theological studies of the language of the New Testament helped prepare the way for Gerhard Kittelas monumental Theologisches Woerterbuch zum Neuen Testament. When one speaks of the part which Cremer has played in developing a better method for biblical theology, he needs also to mention the names of August Tholuck, Martin Kaehler, and Adolf Schlatter.Tholuck is remarkable in that he anticipated many of the theological developments of our own era. He stressed the theological value of the Old Testament at a time when it was being generally depreciated. He had a keen appreciation for the exegetical skill of the Reformers and sought to make their writings more widely- known. Calvin's New Testament commentaries were republished with Tholuck as editor. Tholuck's theology had an emancipating effect on a whole generation of German theological students, and his influence extended to America and Britain. The effect was comparable in some respects to that produced in this century by Karl Barth's critique of liberal Protestantism. Tholuck, too, was the author of a commentary on Romans which was the signal for a new movement. Tholuck's connections with Pietism are well -known, yet few realize that he was a Church theologian as well. The relation between Tholuck and Cremer was that of teacher and pupil, and it is Tholuck's influence upon Cremer in his formative years that merits our chief consideration.Cremer and his friends Kaehler and Schlatter do not form "a school" in the strictest sense. Each was an individualist. They differed in background, temperament, and outlook. Cremer and Kaehler were Lutheran; Schlatter was Reformed. But they had this in common; they were all biblical theologians. They combined confidence in the biblical witness with thoroughgoing historical research. This was the distinctive and significant feature of their hermeneutics. They understood theology to be a scientific discipline. Because they differed from one another, these three scholars could work in a reciprocal, complementary relationship which provided mutual correction and encouragement. Their collaboration ultimately found expression in the periodical Beitraege zur Foerderung christlicher Theologie. In their opposition to liberalism they were not combatting the historico- critical method but a one -sided emphasis on this method, a tendency for autonomous man to set himself up as judge over Scripture. This was what kept Cremer and his associates apart from the exegesis of F.C. Baur, from the idea of evolution as a hermeneutical canon, from the Ritschlian theology, and from Harnack with his "essence of Christianity". Thus they stood aloof from all the major theological movements of the latter half of the nineteenth century. By refusing to be liberals they did not thereby fall back into a historical rationalism or a biblicist fundamentalism. Rather, they are forerunners of that biblical theology which has been characteristic of the theological reawakening in Europe since World War I and in America since World Wear II.I have not attempted to write a full biography of Greiner, nor do I feel obliged to assess his theological position in relation to his famous contemporaries, nor am I interested in his role in German church politics. These matters have been adequately dealt with elsewhere. My chief concern is with his Biblisch theologisches Woerterbuch, for therein lies the heart of his theology, and in it, too, is to be found the key to his method of interpreting Scripture

Global Seismic Oscillations in Soft Gamma Repeaters

There is evidence that soft gamma repeaters (SGRs) are neutron stars which experience frequent starquakes, possibly driven by an evolving, ultra-strong magnetic field. The empirical power-law distribution of SGR burst energies, analogous to the Gutenberg-Richter law for earthquakes, exhibits a turn-over at high energies consistent with a global limit on the crust fracture size. With such large starquakes occurring, the significant excitation of global seismic oscillations (GSOs) seems likely. Moreover, GSOs may be self-exciting in a stellar crust that is strained by many, randomly-oriented stresses. We explain why low-order toroidal modes, which preserve the shape of the star and have observable frequencies as low as ~ 30 Hz, may be especially susceptible to excitation. We estimate the eigenfrequencies as a function of stellar mass and radius, and their magnetic and rotational shiftings/splittings. We also describes ways in which these modes might be detected and damped. There is marginal evidence for 23 ms oscillations in the hard initial pulse of the 1979 March 5th event. This could be due to the $_3t_0$ mode in a neutron star with B ~ 10^{14} G or less; or it could be the fundamental toroidal mode if the field in the deep crust of SGR 0526-66 is ~ 4 X 10^{15} G, in agreement with other evidence. If confirmed, GSOs would give corroborating evidence for crust-fracturing magnetic fields in SGRs: B >~ 10^{14} G.Comment: 12 pages, AASTeX, no figures. Accepted for Astrophysical Journal Letter

The Size and Nature of Lyman alpha Forest Clouds Probed by QSO Pairs and Groups

We describe a robust Bayesian statistical method for determining Lyman alpha forest cloud sizes in spherical and in thin disk geometries, using absorption in adjacent sightlines toward closely separated QSO pairs and groups, apply this method to the available data, and discuss implications of our results for models of Ly alpha clouds. Under the assumption of a population of uniform- size and unclustered clouds, the data from Q1343+2640A/B give a 99% confidence lower and upper bounds 61<R<533 kpc/h on the radius of spherical clouds at z about 1.8, with a median value of 149 kpc/h [$(\Omega_0, \Lambda_0) =(1,0)$]. The baryonic mass of such large clouds is comparable to that of dwarf irregular galaxies. Their cosmic overdensity is close to the turn-around density but generally below the virialization density, suggesting a population of gravi- tationally bound but unvirialized protogalactic objects at z about 2. Their comoving volume density is similar to that of the faint blue galaxies (FBGs) at the limiting magnitude B of 26-27. The dynamical collapsing timescale of over- densities like these clouds is also comparable with the cosmic time difference between z of 2 to 1. Both populations of objects show similar weak clustering in space. All this evidence suggests a possible identification of Ly alpha clouds as the collapsing progenitors of the FBGs at z about 1. We also investigate the other QSO pairs: Q0307-1931/1932, Q0107-0232/0235, and the triplet of Q1623+268. Imposing an uniform W_0 > 0.4 A threshold on all linelists, we find a trend of larger inferred cloud radius with larger proper separation of QSO pairs, significant at the 3.4 sigma level. This indicates that the idealization of unclustered, uniform-sized clouds does not accurately describe the Ly alpha cloud population.Comment: Astrophysical Journal accepted; 28 pages of uuencoded gzip compressed postscript file (including 8 figures). Also see the uncompressed postscript file at http://www.astro.columbia.edu/~fang

Characterization Test Report for the Mnemonics-UCS Wireless Surface Acoustic Wave Sensor System

The scope of this testing includes the Surface Acoustic Wave Sensor System delivered to KSC: two interrogator (transceiver) systems, four temperature sensors, with wooden mounting blocks, two antennas, two power supplies, network cables, and analysis software. Also included are a number of additional temperature sensors and newly-developed hydrogen sensor

RFLP markers and genetic linkage of oil content and hypodermis color in sunflower seed (Helianthus annuus L.)

The service sector is dependent upon customers’ willingness to contribute their knowledge, skills, and abilities to co-produce the service experiences they want and expect. Service organizations therefore seek to employ strategies that will enhance their customers’ ability to do whatever they must to be successful in co-producing those experiences. Applying the concept of self-efficacy, we offer a theory-based approach to developing these strategies that firms may utilize. These strategies involve focusing both employee training and environmental cues on how to enhance the self-efficacy of the customer in performing whatever tasks are necessary toward a successful service experience