Transcontinental baselines and the rotation of the Earth measured by radio interferometry.

Nine separate very-long-baseline interferometry (VLBI) experiments, carried out in 1972 and 1973 with radio telescopes 3900 kilometers apart, yielded values for the baseline length with a root-mean-square deviation about the mean of less than 20 centitneters. The corresponding fractional spread is about five parts in 10(8). Changes in universal time and in polar motion were also detertnined accurately from these data; the root-mean-square scatter of these results with respect to those based on optical methods were 2.9 milliseconds and 1.3 meters, respectively. Solid-earth tides were apparently detected, but no useful estimate of their amplituide was extracted.

Quasars: Millisecond-of-Arc Structure Revealed by Very-Long-Baseline Interferometry.

Observations with the Goldstone-Haystack radio interferometer of the quasars 3C 279 and 3C 273 have disclosed the presence of fine structure in their radio emissions. Although the interpretation is not unique, the fringe-amplitude data for quasar 3C 279 are quite consistent with emissions from two points, each contributing equally to the correlated flux. The separation of the two points is estimated to be (1.55 +/- 0.05) x 10(-3) arc second, or about 20 light years at the distance of 3 x 10(9) light years inferred from optical red-shift data. The formal uncertainty in the right-ascension component of the separation is about 6 x 10(-6) arc second; differential proper motion in this direction at half the speed of light could be discerned within a year. The fringe-amplitude data of quasar 3C 273 allow similar, but less definitive, interpretations.

Quasars revisited: rapid time variations observed via very-long-baseline interferometry.

Recent Goldstone-Haystack radio interferometric observations of the quasars 3C 279 and 3C 273 reveal rapid variations in their fine structure. Most notably, the data for 3C 279, interpreted in terms of a symmetric double-source model and the accepted red-shift distance, indicate differential proper motion corresponding to an apparent speed about ten times that of light. A number of possible mechanisms that might give rise to such an apparent speed are considered; although several may be plausible, no definitive choice can be made on the basis of present evidence. More interferometric observations of quasars are clearly needed to clarify their structure and internal kinematics.

Precision Geodesy via Radio Interferometry.

Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds.

Interferometric observations of an artificial satellite.

Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differenced delay and delay-rate measurements reached 0.15 nanosecond ( approximately 5 centimeters in equivalent differenced distance) and 0.05 picosecond per second ( approximately 0.002 centimeter per second in equivalent differenced velocity), respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy. Comparisons are made with other techniques.

Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis.

The Mark III very-long-baseline interferometry (VLBI) system allows recording and later processing of up to 112 megabits per second from each radio telescope of an interferometer array. For astrometric and geodetic measurements, signals from two radio-frequency bands (2.2 to 2.3 and 8.2 to 8.6 gigahertz) are sampled and recorded simultaneously at all antenna sites. From these dual-band recordings the relative group delays of signals arriving at each pair of sites can be corrected for the contributions due to the ionosphere. For many radio sources for which the signals are sufficiently intense, these group delays can be determined with uncertainties under 50 picoseconds. Relative positions of widely separated antennas and celestial coordinates of radio sources have been determined from such measurements with 1 standard deviation uncertainties of about 5 centimeters and 3 milliseconds of arc, respectively. Sample results are given for the lengths of baselines between three antennas in the United States and three in Europe as well as for the arc lengths between the positions of six extragalactic radio sources. There is no significant evidence of change in any of these quantities. For mapping the brightness distribution of such compact radio sources, signals of a given polarization, or of pairs of orthogonal polarizations, can be recorded in up to 28 contiguous bands each nearly 2 megahertz wide. The ability to record large bandwidths and to link together many large radio telescopes allows detection and study of compact sources with flux densities under 1 millijansky.

Immediate Nerve Transfer for the Treatment of Peroneal Nerve Palsy Secondary to an Intraneural Ganglion: Case Report and Review.

Intraneural ganglion cysts that occur within the common peroneal nerve are a rare cause of foot drop. The current standard of treatment for intraneural ganglion cysts involving the common peroneal nerve involves (1) cyst decompression and (2) ligation of the articular nerve branch to prevent recurrence. Nerve transfers are a time-dependent strategy for recovering ankle dorsiflexion in cases of high peroneal nerve palsy; however, this modality has not been performed for intraneural ganglion cysts involving the common peroneal nerve. We present a case of common peroneal nerve palsy secondary to an intraneural ganglion cyst occurring in a 74-year-old female. The patient presents with a 5-month history of pain in the right common peroneal nerve distribution and foot drop. The patient underwent simultaneous cyst decompression, articular nerve branch ligation, and nerve transfer of the motor branch to the flexor hallucis longus to a motor branch of the anterior tibialis muscle. At final follow-up, the patient demonstrated complete (M4+) return of ankle dorsiflexion, no pain, and no evidence of recurrence and was able to weight bare without the need of orthotic support. Given the minimal donor site morbidity and recovery of ankle dorsiflexion, this report underscores the importance of considering early nerve transfers in cases of high peroneal neuropathy due to an intraneural ganglion cyst.

Les kystes intraneuraux de ganglions qui se forment sur le péronier proximal sont une rare cause de pied tombant. La norme actuelle du traitement de ce type de kyste sur le péronier proximal comprend 1) la décompression du kyste et 2) la ligature de la ramification du nerf articulaire pour éviter une récurrence. Le transfert des nerfs est une stratégie limitée dans le temps pour récupérer la dorsiflexion de la cheville en cas de paralysie importante du péronier. Cependant, cette modalité n'a pas été utilisée pour traiter des kystes intraneuraux du ganglion touchant le nerf du péronier proximal. Les auteurs présentent le cas d'une paralysie du péronier proximal causée par un kyste intraneural de ganglion chez une femme de 74 ans. La patiente a consulté parce qu'elle ressentait une douleur dans le péronier proximal droit et avait un pied tombant depuis cinq mois. Elle a subi une décompression du kyste, une ligature de la ramification du nerf articulaire et le transfert du nerf de la ramification motrice du long fléchisseur de l'hallux à une ramification motrice du muscle du tibia antérieur. Au dernier suivi, elle présentait une récupération complète (M4+) de la dorsiflexion de la cheville, ne souffrait plus d'aucune douleur et n'avait aucune trace de récurrence. Elle pouvait supporter son poids sans orthèse. Compte tenu de la morbidité minime au site du donneur et de la récupération de la dorsiflexion de la cheville, le présent rapport fait ressortir l'importance d'envisager le transfert précoce des nerfs en cas de neuropathie importante du péronier causée par un kyste intraneural de ganglion.

Housing instability and homelessness among rural schizophrenic patients.

OBJECTIVE: The authors examined housing instability among treated schizophrenic patients in a rural area and compared the findings with those from their previous study of urban patients. METHOD: Seventy-five patients with schizophrenia or schizoaffective disorder who were treated in a rural mental health center were assessed with research interviews and ratings by their clinical case managers. The patients were followed for 1 year to identify episodes of psychiatric hospitalization, incarceration, and literal homelessness. RESULTS: Of the 75 patients, 19 (25%) had housing situations characterized as unstable by their case managers. For the majority, housing instability signified tenuousness of living arrangements rather than literal homelessness. Noncompliance with medications, alcohol use, and negative symptoms accounted for 30% of the variance in unstable housing. During follow-up, the unstably housed patients, compared to those in stable living situations, were no more likely to be rehospitalized but were somewhat more likely to be jailed and significantly more likely to be literally homeless. CONCLUSIONS: In the authors' previous study of urban psychiatric patients, unstably housed patients were more likely to be literally homeless, highly symptomatic, and rehospitalized during follow-up than the rural patients with unstable housing. Better outcomes in the rural area appeared to be related to the greater availability of housing alternatives and to intensive case management. For patients with unstable housing in both settings, noncompliance with medications and substance abuse, as well as housing arrangements, should be assertively addressed.

Cardiac myxoma arising from the inferior vena cava.

This report documents what we believe to be the first reported case of a cardiac myxoma originating from inferior vena caval tissue. Myxomas account for 50 percent of cardiac tumors and present with either embolic, obstructive, or constitutional symptoms and signs. Diagnosis is facilitated by angiography and echocardiography and should be followed promptly by careful and complete removal of the mass and adjacent tissue with close follow-up by clinical and echocardiographic examinations.

Cardiovascular complications of non-insulin-dependent diabetes: the JCR:LA-cp rat.

Diabetes is a serious medical and financial burden on western societies. It is the seventh leading cause of death in the United States and Canada. The disease is due to a primary defect in glucose tolerance and carbohydrate metabolism resulting from either a deficiency of insulin (Insulin-dependent (type I) diabetes mellitus - IDDM) or a state of insulin resistance (Non-insulin-dependent (type II) diabetes mellitus - NIDDM). NIDDM comprises greater than 80% of total diabetic cases. Associated with the primary metabolic defects are equally deleterious secondary complications affecting the renal, ocular, nervous and cardiovascular systems. The cardiovascular complications account for a major proportion of diabetic mortality. As such, it is of paramount importance to develop or find an animal model expressing complications homologous to the human condition. Many models of NIDDM are available to the diabetic researcher but choosing an accurate one can be difficult. The following compares the advantages and limitations of one such model, the JCR:LA-cp rat to other NIDDM models commonly used today.

Potential phosphorus recovery by struvite formation.

Formation of struvite (MgNH4PO4 x 6H2O) at sewage treatment works can cause operational problems and decrease efficiency. Struvite has a commercial value and the controlled formation and recovery of it would be beneficial. A mass balance was conducted at full scale across the whole sewage treatment plant in order to identify a stream to conduct bench-scale struvite crystallisation studies. The most suitable stream was identified as the centrifuge liquors. The average flow of the liquor stream was 393 m3 d(-1) and the composition was as follows: 167 mg L(-1) phosphorus, 44 mg L(-1) magnesium, 615 mg L(-1) ammonium, 56 mg L(-1) calcium and 2580 mg L(-1) of alkalinity. The pH averaged at 7.6 and the stream had a predicted struvite precipitation potential of 140 mg L(-1). Struvite crystallisation occurred quickly during the trials, by raising the pH of the centrifuge liquors to 9.0 and dosing with magnesium. Up to 97% phosphorus removal as struvite was achieved. Struvite formation occurred when the molar ratio of magnesium:phosphorus was at least 1.05:1. Below this ratio phosphorus removals of 72% were observed, but not exclusively as struvite. Annual yields of struvite were calculated to be 42-100 tonnes a year, depending on the dose regime. Revenue from the sale of produced struvite could be between Pound Sterling8400 and Pound Sterling20,000 a year.

Mg2+-dependent ATPase activity in cardiac myofibrils from the insulin-resistant JCR:LA-cp rat.

There is a great deal of information presently available documenting a cardiomyopathic condition in insulin-deficient models of diabetes. Less information is available documenting a similar status in non insulin-dependent models of diabetes. We have studied the functional integrity of the myofibrils isolated from hearts of JCR:LA rats. The JCR:LA rat is hyperinsulinemic, hyperlipidemic, glucose intolerant and obese. As such, it carries many of the characteristics found in humans with non insulin-dependent diabetes mellitus. These animals also have many indications of heart disease. However, it is not clear if the hearts suffer from vascular complications or are cardiomyopathic in nature. We examined Mg2+-dependent myofibrillar ATPase in hearts of JCR:LA-cp/cp rats and their corresponding control animals (+/?) and found no significant differences (P> 0.05). This is in striking contrast to the depression in this activity exhibited by cardiac myofibrils isolated from insulin-deficient models of diabetes. Our data demonstrate that myofibrillar functional integrity is normal in JCR:LA-cp rats and suggest that these hearts are not in a cardiomyopathic state. Insulin status may be critical in generating a cardiomyopathic condition in diabetes.

Prevalence of drugs and alcohol in autopsied homicide cases in St. John Parish, Louisiana.

This article presents a retrospective review of all autopsies conducted by the St. John Parish coroner's office between January 1992 and June 1995. The overall prevalence of illicit drugs or alcohol detectable in the autopsied homicide cases for that time period was 60%. Cocaine was the most prevalent substance, detected in 40% of homicide victims. This study also describes a preponderance of firearm violence among homicide cases, and an overrepresentation of young black men with detectable blood levels of drugs or alcohol at time of death. The data from this rural/suburban parish closely parallels that collected from larger urban areas in recent years. These trends in less urban areas will likely further come to resemble those in large cities, and continue to tax health care and community service resources.

Recent SETI observations at Arecibo.

During 1980 and 1981, the 305-m radio telescope at the Arecibo Observatory in Puerto Rico was used to conduct a high resolution search for narrowband signals from the direction of 210 nearby solar type stars and 5 OH masers. For each star at least 4 MHz of bandwidth surrounding the 21-cm HI line and/or the 18-cm OH lines was studied with a spectral resolution of 5.5 Hz in both right and left circular polarization. The formal limit of sensitivity achieved during the course of this search varied depending upon the particular receivers available. In all cases the search could have detected a narrowband transmitter of power comparable to the Arecibo planetary radar, had any such been transmitting on the frequencies searched during the time of observation out to the distance of the farthest target star. As in previous searches, the number of "false alarms" encountered was far greater than predicted on the basis of Gaussian noise statistics. A small number of stars have exhibited signals which cannot immediately be explained in terms of astrophysical or man-made sources and deserve reobservation. This is typical of the results of previous non-real-time searches and does not yet constitute the detection of an ETI.

Balloon-borne far-infrared Michelson interferometer for atmospheric emission studies.

A series of far-ir Michelson interferometers utilizing the rapid-scanning technique have been designed and built for balloon-borne measurement of the emission spectrum of the stratosphere. Design criteria for such instrumentation are presented, and details of the evolution of these designs are discussed, including liquid helium-cooled bolometer detector systems, internal blackbody calibration, and atmospheric limb-scanning. Stratospheric emission spectra between 30 cm(-1) and 110 cm(-1) at a resolution of 0.07 cm(-2) are presented as examples of results taken at balloon altitudes, and the merits of this type of instrumentation for monitoring stratospheric trace gas constituent concentrations are discussed.

An attempt to infer the electrophysiological functions of some intracellular structures in cardiac cells by an electronic analogue.

A circuit which simulates the electrical conduction characteristics of the neuron has been modified by the addition of a feedback loop to simulate the electrical properties of some of the "specialized" tissues of the mammalian heart. It is suggested that there is similar electrical feedback in the muscle cells which is responsible for their electrical properties, and possible relationships between the feedback and observed structures are discussed.

Eliminating channel spectra in Fourier transform spectroscopy.

A numerical method for eliminating channel spectra from data obtained with a bandlimited infrared Fourier transform spectrometer is developed. The method is compared with others in common use on a synthetic model spectrum.