Predictions of pressure-induced transition temperature increase for a variety of high temperature superconductors

A wide variety of superconducting oxides are used to test a general model of high pressure induced transition temperature (T c) changes. The T c 's vary from a low of 24 K to a high of 164 K. Although the model is capable of predicting both increases and decreases in T c with pressure, only superconductors that exhibit an increase are considered at this time. Predictions are made of the maximum T^ cP theo for 15 super-conductors as a function of their compressibilities. The theoretical results generally agree well with experiment. This model of T c as a function of pressure is derived from a recent successful phenomenological theory of short coherence length superconductivity.Comment: 9 pages. 1 table, 0 figure

Phenomenological theory of cuprate superconductivity

Reasonably good agreement with the superconducting transitiontemperatures of the cuprate high‐T c superconductors can be obtained on the basis of an approximate phenomenological theory. In this theory, two criteria are used to calculate the superconducting transitiontemperature. One is that the quantum wavelength is of the order of the electron‐pair spacing. The other is that a fraction of the normal carriers exist as Cooper pairs at T c . The resulting simple equation for T c contains only two parameters: the normal carrier density and effective mass. We calculate specific transition temperatures for 12 cuprate superconductors

Automated detection of asteroids in real-time with the Spacewatch telescope

The Spacewatch telescope on Kitt Peak is being used to survey for near-earth asteroids using a Tektronix TK2048 CCD in scanning mode. We hope to identify suitable low delta v candidates amongst the near-earth asteroid population as possible exploration targets, to identify those objects which pose a danger to life on earth, and to study the physical properties of the objects in near-earth space. Between Sep. 1990 and Jun. 1991, 14 new earth-approaching asteroids including 1 Aten, 9 Apollo, and 4 Amor type asteroids were detected by automated software and discriminated by their angular rates from the rest of the detected asteroids in near-real time by the observer. The average of about 1.5 earth-approaching asteroids per month is comparable to the total number found by all other observatories combined. One other Apollo type asteroid was detected by the observer as a long trailed image. The positions of this last object were measured and the object was tracked by the observer in real time. This object was determined to be a 5-10 meter diameter object which passed within 170,000 kilometers of earth. Of the 14 automatically detected earth-approaching asteroids, 10 have been found at distances in excess of 0.5 AU from earth. An average of more than 2000 asteroids are detected each month. Positions, angular rates, and brightnesses are determined for each of these asteroids in real-time

Periods, Organized (PeriodO): A gazetteer of period assertions for linking and visualizing periodized data

The PeriodO project seeks to create an online gazetteer of authoritative assertions about the chronological and geographic extent of historical and archaeological periods. Starting with a trial dataset related to Classical antiquity, this gazetteer will combine period thesauri used by museums and cultural heritage bodies with published assertions about the dates and locations of periods in authoritative print sources. These assertions will be modeled in a Linked Data format (JSON-LD, a serialization of RDF). They will be given Uniform Resource Identifiers (URIs) and served from a public GitHub repository, where they can act as a shared reference point to describe data in datasets with periodized information. We will also create a search and visualization tool to view the temporal and geographic extent of an assertion and compare it with others. Authoritative users will be able to add their own period assertions

The Formation of the Collisional Family around the Dwarf Planet Haumea

Haumea, a rapidly rotating elongated dwarf planet (~ 1500 km in diameter), has two satellites and is associated with a "family" of several smaller Kuiper Belt objects (KBOs) in similar orbits. All members of the Haumea system share a water ice spectral feature that is distinct from all other KBOs. The relative velocities between the Haumea family members are too small to have formed by catastrophic disruption of a large precursor body, which is the process that formed families around much smaller asteroids in the Main Belt. Here we show that all of the unusual characteristics of the Haumea system are explained by a novel type of giant collision: a graze-and-merge impact between two comparably sized bodies. The grazing encounter imparted the high angular momentum that spun off fragments from the icy crust of the elongated merged body. The fragments became satellites and family members. Giant collision outcomes are extremely sensitive to the impact parameters. Compared to the Main Belt, the largest bodies in the Kuiper Belt are more massive and experience slower velocity collisions; hence, outcomes of giant collisions are dramatically different between the inner and outer solar system. The dwarf planets in the Kuiper Belt record an unexpectedly large number of giant collisions, requiring a special dynamical event at the end of solar system formation.Comment: Accepted for publication in ApJ, 12 pages, 4 figures, 2 tables

Epic and the Russian Novel from Gogol to Pasternak

"Epic and the Russian Novel from Gogol to Pasternak examines the origin of the nineteen- century Russian novel and challenges the Lukács-Bakhtin theory of epic. By removing the Russian novel from its European context, the authors reveal that it developed as a means of reconnecting the narrative form with its origins in classical and Christian epic in a way that expressed the Russian desire to renew and restore ancient spirituality. Through this methodology, Griffiths and Rabinowitz dispute Bakhtin’s classification of epic as a monophonic and dead genre whose time has passed. Due to its grand themes and cultural centrality, the epic is the form most suited to newcomers or cultural outsiders seeking legitimacy through appropriation of the past. Through readings of Gogol’s Dead Souls—a uniquely problematic work, and one which Bakhtin argued was novelistic rather than epic—Dostoevsky’s Brothers Karamazov, Pasternak’s Dr. Zhivago, and Tolstoy’s War and Peace, this book redefines “epic”

Scheme and Scale Dependence of Charm Production in Neutrino Scattering

We discuss some theoretical uncertainties in the calculation of the cross section for charm production in charged current deep inelastic neutrino scattering related to ambiguities in the treatment of terms which are singular in the limit of a vanishing charm mass. In particular we compare the so-called variable flavour scheme where these terms are absorbed in the parton distribution functions containing the charm as an active flavour, with the so-called fixed flavour scheme with no charm mass subtraction where the charm appears only in the final state of fixed-order scattering matrix elements. Using available parametrizations of parton distribution functions we find that the two schemes lead to largely differing results for separate structure functions whereas the differences cancel to a large extent in the total cross section in that kinematical region which has been measured so far.Comment: 20pages, uuencoded postscript, figures include