Gurses' Type (b) Transformations are Neighborhood-Isometries

Following an idea close to one given by C. G. Torre (private communication), we prove that Riemannian spaces (M,g) and (M,h) that are related by a Gurses type (b) transformation [M. Gurses, Phys. Rev. Lett. 70, 367 (1993)] or, equivalently, by a Torre-Anderson generalized diffeomorphism [C. G. Torre and I. M. Anderson, Phys. Rev. Lett. xx, xxx (1993)] are neighborhood-isometric, i.e., every point x in M has a corresponding diffeomorphism phi of a neighborhood V of x onto a generally different neighborhood W of x such that phi*(h|W) = g|V.Comment: 10 pages, LATEX, FJE-93-00

A cooled telescope for infrared balloon astronomy

The characteristics of a 16 inch liquid helium cooled Cassegrain telescope with vibrating secondary mirror are discussed. The telescope is used in making far infrared astronomical observations. The system houses several different detectors for multicolor photometry. The cooled telescope has a ten to one increase in signal-to-noise ratio over a similar warm version and is installed in a high altitude balloon gondola to obtain data on the H2 region of the galaxy

POLICY DEVELOPMENTS IN UNITED STATES AGRICULTURE SINCE 1986

Agricultural and Food Policy,

Doppler Probe of Accretion onto a T Tauri star

The YY Ori stars are T Tauri stars with prominent time-variable redshifted absorption components that flank certain emission lines. One of the brightest in this class is S CrA, a visual double star. We have obtained a series of high-resolution spectra of the two components during four nights with the UVES spectrograph at the Very Large Telescope. We followed the spectral changes occurring in S CrA to derive the physical structure of the accreting gas. We found that both stars are very similar with regard to surface temperature, radius, and mass. Variable redshifted absorption components are particularly prominent in the SE component. During one night, this star developed a spectrum unique among the T Tauri stars: extremely strong and broad redshifted absorption components appeared in many lines of neutral and ionized metals, in addition to those of hydrogen and helium. The absorption depths of cooler, low ionization lines peak at low velocities - while more highly ionized lines have peak absorption depths at high velocities. The different line profiles indicate that the temperature and density of the accretion stream increase as material approaches the star. We derive the physical conditions of the flow at several points along the accretion funnel directly from the spectrum of the infalling gas. We estimated mass accretion rates of about 10^(-7) solar masses per year, which is similar to that derived from the relation based on the strength of H alpha emission line. This is the first time the density and temperature distributions in accretion flows around a T Tauri star have been inferred from observations. Compared with predictions from standard models of accretion in T Tauri stars, which assume a dipole stellar magnetic field, we obtained higher densities and a steeper temperature rise toward the star.Comment: Replaces 1408.1846 4 pages, 4 figures. Appears in Astronomy and Astrophysics, 201

Two stage superconducting quantum interference device amplifier in a high-Q gravitational wave transducer

We report on the total noise from an inductive motion transducer for a gravitational-wave antenna. The transducer uses a two-stage SQUID amplifier and has a noise temperature of 1.1 mK, of which 0.70 mK is due to back-action noise from the SQUID chip. The total noise includes thermal noise from the transducer mass, which has a measured Q of 2.60 X 10^6. The noise temperature exceeds the expected value of 3.5 \mu K by a factor of 200, primarily due to voltage noise at the input of the SQUID. Noise from flux trapped on the chip is found to be the most likely cause.Comment: Accepted by Applied Physics Letters tentatively scheduled for March 13, 200

Implications of kHz QPOs for the spin frequencies and magnetic fields of neutron stars: new results from Circinus X-1

Detection of paired kilohertz quasi-periodic oscillations (kHz QPOs) in the X-ray emission of a compact object is compelling evidence that the object is an accreting neutron star. In many neutron stars, the stellar spin rate is equal or roughly equal to Delta-nu, the frequency separation of the QPO pair, or to 2Delta-nu. Hence, if the mechanism that produces the kilohertz QPOs is similar in all stars, measurement of Delta-nu can provide an estimate of the star's spin rate. The involvement of the stellar spin in producing Delta-nu indicates that the magnetic fields of these stars are dynamically important. We focus here on the implications of the paired kHz QPOs recently discovered in the low-mass X-ray binary (LMXB) system Cir X-1 (Boutloukos et al. 2006). The kHz QPOs discovered in Cir X-1 are generally similar to those seen in other stars, establishing that the compact object in the Cir X-1 system is a neutron star. However, the frequency nu-u of its upper kHz QPO is up to a factor of three smaller than is typical, and Delta-nu varies by about a factor 2 (167 Hz, the largest variation so far observed). Periodic oscillations have not yet been detected from Cir X-1, so its spin rate has not yet been measured directly. The low values of nu-u and the large variation of Delta-nu challenge current models of the generation of kHz QPOs. Improving our understanding of Cir X-1 will improve our knowledge of the spin rates and magnetic fields of all neutron stars.Comment: 3 pages, 3 figures, a table with all known accreting millisecond X-ray pulsars up to October 2007. To appear in "40 Years of Pulsars, Millisecond Pulsars, Magnetars and More" conference proceeding

A Multi-Band Far-Infrared Survey with a Balloon-Borne Telescope

Nine additional radiation sources, above a 3-sigma confidence level of 1300 Jy, were identified at 100 microns by far infrared photometry of the galactic plane using a 0.4 meter aperture, liquid helium cooled, multichannel far infrared balloon-borne telescope. The instrument is described, including its electronics, pointing and suspension systems, and ground support equipment. Testing procedures and flight staging are discussed along with the reduction and analysis of the data acquired. The history of infrared astronomy is reviewed. General infrared techniques and the concerns of balloon astronomers are explored

The Economics of Books

The tensions between books and book markets as expressions of culture and books as products in profit-making businesses are analysed and insights from the theory of industrial organisation are given. Governments intervene in the market for books through laws concerning prices of books, grants for authors and publishers, a lower value-added tax, public libraries and education in order to stimulate the diversity of books on offer, increase the density of retail outlets and to promote reading. An overview of the different ways by which countries differ in terms of market structures and government policies is given. Particular attention is paid to retail price maintenance. Due to differences between European countries it is not a good idea to harmonise European book policies. Our analysis suggests that the book market seems quite able to invent solutions to specific problems of the book trade and that, apart from promoting reading, there is little need for government intervention.books, publishers, authors, diversity, monopolistic competition, retail price maintenance, subsidies, libraries, internet