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We have used the Sydney University Stellar Interferometer (SUSI) to measure the angular diameter of beta Hydri. This star is a nearby G2 subgiant whose mean density was recently measured with high precision using asteroseismology. We determine the radius and effective temperature of the star to be 1.814+/-0.017 R_sun (0.9%) and 5872+/-44 K (0.7%) respectively. By combining this value with the mean density, as estimated from asteroseismology, we make a direct estimate of the stellar mass. We find a value of 1.07+/-0.03 M_sun (2.8%), which agrees with published estimates based on fitting in the H-R diagram, but has much higher precision. These results place valuable constraints on theoretical models of beta Hyi and its oscillation frequencies., 3 figures, 3 tables, to appear in MNRAS Letters

The first orbital solution for the spectroscopic pair in the multiple star system sigma Scorpii, determined from measurements with the Sydney University Stellar Interferometer (SUSI), is presented. The primary component is of beta Cephei variable type and has been one of the most intensively studied examples of its class. The orbital solution, when combined with radial velocity results found in the literature, yields a distance of 174(+23,-18) pc, which is consistent with, but more accurate than the Hipparcos value. For the primary component we determine 18.4+/-5.4 M_sun, -4.12+/-0.34 mag and 12.7+/-1.8 R_sun for the mass, absolute visual magnitude and radius respectively. A B1 dwarf spectral type and luminosity class for the secondary is proposed from the mass determination of 11.9+/-3.1 M_sun and the estimated system age of 10 Myr.

The first complete orbital solution for the double-lined spectroscopic binary system \gamma^2 Velorum, obtained from measurements with the Sydney University Stellar Interferometer (SUSI), is presented. This system contains the closest example of a Wolf-Rayet star and the promise of full characterisation of the basic properties of this exotic high-mass system has subjected it to intense study as an archetype for its class. In combination with the latest radial-velocity results, our orbital solution produces a distance of 336^{+8}_{-7} pc, significantly more distant than the Hipparcos estimation (Schaerer et al. 1997; van der Hucht 1997). The ability to fully specify the orbital parameters has enabled us to significantly reduce uncertainties and our result is consistent with the VLTI observational point (Millour et al. 2006), but not with their derived distance. Our new distance, which is an order of magnitude more precise than prior work, demands critical reassessment of all distance-dependent fundamental parameters of this important system. In particular, membership of the Vela OB2 association has been reestablished, and the age and distance are also in good accord with the population of young stars reported by Pozzo et al. (2000). We determine the O-star primary component parameters to be M_V(O) = -5.63 \pm 0.10 mag, R(O) = 17 \pm 2 R_{\sun} and {\cal M}(O) = 28.5 \pm 1.1 M_{\sun}. These values are consistent with calibrations found in the literature if a luminosity class of II--III is adopted. The parameters of the Wolf-Rayet component are M_v(WR) = -4.33 \pm 0.17 mag and {\cal M}(WR) = 9.0 \pm 0.6 M_{\sun}., Comment: 3 figures, accepted for publication in MNRAS

The Sydney University Stellar Interferometer (SUSI) has been used to make a new determination of the angular diameter of Sirius A. The observations were made at an effective wavelength of 694.1 nm and the new value for the limb-darkened angular diameter is 6.048 +/- 0.040mas (+/-0.66%). This new result is compared with previous measurements and is found to be in excellent agreement with a conventionally calibrated measurement made with the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at 2.176 microns (but not with a second globally calibrated VLTI measurement). A weighted mean of the SUSI and first VLTI results gives the limb-darkened angular diameter of Sirius A as 6.041 +/- 0.017mas (+/-0.28%). Combination with the Hipparcos parallax gives the radius equal to 1.713 +/- 0.009R_sun. The bolometric flux has been determined from published photometry and spectrophotometry and, combined with the angular diameter, yields the emergent flux at the stellar surface equal to (5.32+/- 0.14)x10^8 Wm^-2 and the effective temperature equal to 9845 +/- 64 K. The luminosity is 24.7 +/- 0.7 L_sun., Accepted for publication in PASA

We have used the Sydney University Stellar Interferometer (SUSI) to measure the angular diameter of the F9 V star beta Virginis. After correcting for limb darkening and combining with the revised Hipparcos parallax, we derive a radius of 1.703 +/- 0.022 R_sun (1.3%). We have also calculated the bolometric flux from published measurements which, combined with the angular diameter, implies an effective temperature of 6059 +/- 49 K (0.8%). We also derived the luminosity of beta Vir to be L = 3.51 +/- 0.08 L_sun (2.1%). Solar-like oscillations were measured in this star by Carrier et al. (2005) and using their value for the large frequency separation yields the mean stellar density with an uncertainty of about 2%. Our constraints on the fundamental parameters of beta Vir will be important to test theoretical models of this star and its oscillations., accepted for publication in MNRAS. Updated references

The binary star delta Sco (HD143275) underwent remarkable brightening in the visible in 2000, and continues to be irregularly variable. The system was observed with the Sydney University Stellar Interferometer (SUSI) in 1999, 2000, 2001, 2006 and 2007. The 1999 observations were consistent with predictions based on the previously published orbital elements. The subsequent observations can only be explained by assuming that an optically bright emission region with an angular size of > 2 +/- 1 mas formed around the primary in 2000. By 2006/2007 the size of this region grew to an estimated > 4 mas. We have determined a consistent set of orbital elements by simultaneously fitting all the published interferometric and spectroscopic data as well as the SUSI data reported here. The resulting elements and the brightness ratio for the system measured prior to the outburst in 2000 have been used to estimate the masses of the components. We find Ma = 15 +/- 7 Msun and Mb = 8.0 +/- 3.6 Msun. The dynamical parallax is estimated to be 7.03 +/- 0.15 mas, which is in good agreement with the revised HIPPARCOS parallax., 8 pages, 4 figs. Accepted for publication in MNRAS

The Sydney University Stellar Interferometer (SUSI) has now been operating with a significanly more sensitive beam combiner system (the Red Table) for several years. A number of novel results from the realms of single, binary and pulsating star astrophysics are presented. Simultaneous dual beam-combiner operation with the Red Table and an upgraded Blue Table has been demonstrated, enabling a high spectral dispersion oberving mode for stellar studies. Plans for a major upgrade are briefly described. One component of this will be remote operation of the array for routine observational data taking, with first steps on this path reported here with the inception of the Sydney Remote Operations Center. The backbone of future plans with SUSI center around the installation of the southern of the twin PAVO instruments. PAVO is also discussed in more detail in Ireland et al, this proceedings.

Observations of the southern Cepheid l Car to yield the mean angular diameter and angular pulsation amplitude have been made with the Sydney University Stellar Interferometer (SUSI) at a wavelength of 696 nm. The resulting mean limb-darkened angular diameter is 2.990+-0.017 mas (i.e. +-0.6 per cent) with a maximum-to-minimum amplitude of 0.560+-0.018 mas corresponding to 18.7+-0.6 per cent in the mean stellar diameter. Careful attention has been paid to uncertainties, including those in measurements, in the adopted calibrator angular diameters, in the projected values of visibility squared at zero baseline, and to systematic effects. No evidence was found for a circumstellar envelope at 696 nm. The interferometric results have been combined with radial displacements of the stellar atmosphere derived from selected radial velocity data taken from the literature to determine the distance and mean diameter of l Car. The distance is determined to be 525+-26 pc and the mean radius 169+-8R{solar). Comparison with published values for the distance and mean radius show excellent agreement, particularly when a common scaling factor from observed radial velocity to pulsation velocity of the stellar atmosphere (the p-factor) is used., Comment: 12 pages, 5 figures, accepted by MNRAS

On the Swine Research Farm at the University of Illinois, an anaerobic digester with a 199 m3 reactor operates at a temperature of 35° C and with an average loading rate of 1.7 kgVS/m3/day. Average daily biogas production is 114 m3, consisting of 64% CH4 and 35% CO2. Total solids, volatile solids, and chemical oxygen demand of the swine manure can be reduced by 59%, 66%, and 73%, respectively, during digestion. The biogas is used to fuel a 25 kW engine generator to produce electricity for emergency circuits on the farm.

Observations of the southern Cepheids lCar and β Dor to yield the mean angular diameters and angular pulsation amplitudes have been made with the Sydney University Stellar Interferometer (SUSI)at a wavelength of 700 nm. The results of a preliminary analysis are compared with those obtained with the VLTI at 2.2 μm and excellent agreement between the results from the two instruments is found for lCar but there are significant differences for βDor.

New angular diameter determinations for the bright southern F8 supergiant Delta CMa enable the bolometric emergent flux and effective temperature of the star to be determined with improved accuracy. The spectral flux distribution and bolometric flux have been determined from published photometry and spectrophotometry and combined with the angular diameter to derive the bolometric emergent flux F = (6.50 plus/minus 0.24) x 10^7 W/m^2 and the effective temperature Teff = 5818 plus/minus 53 K. The new value for the effective temperature is compared with previous interferometric and infrared flux method determinations. The accuracy of the effective temperature is now limited by the uncertainty in the bolometric flux rather than by the uncertainty in the angular diameter., 8 pages, 4 figures

A new beam-combination and detection system has been installed in the Sydney University Stellar Interferometer working at the red end of the visual spectrum (wavelength range 500-950 nm) to complement the existing blue-sensitive system (wavelength range 430-520 nm) and to provide an increase in sensitivity. Dichroic beam-splitters have been introduced to allow simultaneous observations with both spectral system, albeit with some restriction on the spectral range of the longer wavelength system (wavelength range 550-760 nm). The blue system has been upgraded to allow remote selection of wavelength and spectral bandpass, and to enable simultaneous operation with the red system with the latter providing fringe-envelope tracking. The new system and upgrades are described and examples of commissioning tests presented. As an illustration of the improvement in performance the measurement of the angular diameter of the southern F supergiant delta CMa is described and compared with previous determinations., Comment: 13 pages, 14 figures

The Sydney University Stellar Interferometer is a long baseline optical interferometer located in northern New South Wales, Australia. It has a North-South array of eleven fixed input siderostat stations giving a range of baselines from 5 to 640 m. Currently ten baselines from 5 to 160 m are fully operational and beam-combination and detection systems for the spectral ranges 430-520nm and 550-950nm are available. Dichroic beam-splitters have been introduced to allow simultaneous observations with both spectral systems. The original blue beam-combination system has been upgraded to improve sensitivity and to allow rapid wavelength switching. A software scheduler has been developed to automate much of the observational procedure including the acquisition of a star, fringe search and acquisition, recording of fringe scans, and the taking of photometric scans. A data pipeline for processing the observational data has been further developed to include seeing corrections and this has improved the calibration of the observational data. Preliminary results of scientific observations with both blue and red systems, including observations of single stars, binary stars and Cepheid variables are described.

The triple system HD158926 (lambda Sco) has been observed interferometrically with the Sydney University Stellar Interferometer and the elements of the wide orbit have been determined. These are significantly more accurate than the previous elements found spectroscopically. The inclination of the wide orbit is consistent with the inclination previously found for the orbit of the close companion. The wide orbit also has low eccentricity, suggesting that the three stars were formed at the same time. The brightness ratio between the two B stars was also measured at lambda = 442nm and 700nm. The brightness ratio and colour index are consistent with the previous classification of lambda Sco A as B1.5 and lambda Sco B as B2. Evolutionary models show that the two stars lie on the main sequence. Since they have have the same age and luminosity class (IV) the mass-luminosity relation can be used to determine the mass ratio of the two stars: M_B/M_A = 0.76+/-0.04. The spectroscopic data have been reanalyzed using the interferometric values for P, T, e and omega, leading to revised values for a_1sin i and the mass function. The individual masses can be found from the mass ratio, the mass function, spectrum synthesis and the requirement that the age of both components must be the same: M_A = 10.4+/-1.3 Msun and M_B = 8.1+/-1.0 Msun. The masses, angular semimajor axis and the period of the system can be used to determine the dynamical parallax. We find the distance to lambda Sco to be 112+/-5 pc, which is approximately a factor of two closer than the HIPPARCOS value of 216+/-42 pc., 8 pages, 4 figures. Accepted for publication by Monthly Notices of the Royal Astronomical Society

We have studied a secondary IgG anti-dinitrophenyl response in dissociated mouse spleen cell cultures which is comparable in magnitude to the responses detected after adoptive transfer. The data indicate that the responsive precursor cell is not a recirculating memory cell but is an intermediate B cell type which appears in vivo after antigen challenge of primed mice. Both antigen and T helper cells are required for in vitro stimulation of the intermediate cell type into the division and maturation steps leading to IgG antibody secretion. The buoyant density of precursor cells has been analyzed by bovine serum albumin density gradient centrifugation, and is consistent with their recent origin by division from memory cells.

Experiments have been carried out to identify the polypeptide components of the Epstein-Barr (EB) virus-determined membrane antigen (MA) complex. Cells were radioiodinated using lactoperoxidase and the 125I-labelled surface antigens, released by Triton X100, were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) after complexing either with human sera having anti-MA activity or with a rabbit antiserum to EB virus. Using cells carrying EB virus isolated from four different conditions, including for the first time nasopharyngeal carcinoma (NPC), we have demonstrated four major polypeptides. One, with a molecular weight of 85,000, was remarkedly constant irrespective of the cell line from which it came; two, with molecular weights varying from 240,000 to 270,000 and from 320,000 to 340,000, showed minor differences in mobility apparently depending on the species of origin of the cells (human or marmoset), rather than disparity between strains of virus. A fourth component, of 160,000 daltons, was found on only two of the cell lines studied. In addition, it has been shown for the first time that the same polypeptides composing the MA complex are present on the viral envelope itself. The fact that the rabbit antiserum to EV virus recognized only the two highest molecular weight MA components, yet showed virus-neutralizing activity, indicates the importance of these two polypeptides for use in a vaccine designed to induce virus-neutralizing antibodies.

It has been suggested that dominant monoclonal responses in mice after transfer of small numbers of spleen cells are the result of strong selection for cell clones producing antibody of high affinity. We have attempted to measure the affinity of anti-DNP (2,4dinitrophenyl) and anti-NIP (4hydroxy5iodo3nitrophenacetyl) antibodies produced in monoclonal responses by inhibition of plaque-forming cells (PFC) with free hapten. PFC from individual monoclonal spleen foci and from spleens after adoptive transfer of 5 × 105 to 2 × 106 primed spleen cells were generally inhibited at lower free antigen concentrations than the PFC found in a heterogeneous secondary response. It was possible to compare several individual cell clones, forming monoclonal antibody to DNP, with respect to the free antigen concentration needed for 50 % plaque inhibition. These comparisons did not correlate well with the relative affinities of serum antibody estimated by the Stupp-Farr technique. Published work analyzing PFC from plasma cell tumor MOPC 315 forming antibody to DNP might have predicted that the curve of PFC inhibition by free hapten for a monoclonal PFC population would be steep. Usually this was not the case, and 20–80 % PFC inhibition occurred over 100-fold concentration range of free hapten. Some of the anti-DNP clones formed large plaques and when these PFC were inhibited by free antigen, the plaque diameter decreased progressively as the hapten concentration increased. Large plaques consequently require more free antigen for inhibition than small plaques. The poor agreement between apparent affinity measured by plaque inhibition and that measured in serum antibody for monoclonal antibody responses may well be a result of the observed differences in plaque size between individual clones. We therefore have strong reservations about the use of plaque inhibition by free antigen to estimate antibody affinity at the cellular level.

Summary Preparative SDS-polyacrylamide gel electrophoresis has been used in the purification of the gp340 component of Epstein-Barr (EB) virus-determined membrane antigen (MA), in tractable quantities, from the B95-8 marmoset lymphoblastoid cell line. Successful renaturation of the purified molecule was achieved. This procedure gave a 50-fold increase in the recovery of antigen compared to conventional techniques. The data suggest that the antigenic sites recognized by human sera containing antibodies to MA are largely confined to the protein portion of the molecule. An eightfold improvement in the yield of gp340 was obtained when B95-8 cells were cultured in the presence of 12-O-tetradecanoyl-phorbol-13-acetate. Gel filtration studies indicate that the major polypeptide components of MA are not associated in detergent solution. Immunization of rabbits with purified and renatured gp340 resulted in the generation of high-titre antisera which were specific for gp340, demonstrating that antigen prepared by this procedure is suitable for further evaluation as an experimental vaccine against EB virus infection.

This paper describes elaborate and severe field tests made on high-speed excitation equipment used with a 5385-kv-a. turbo generator. Complete oscillograms and curves showing the performance of this equipment are included together with a discussion of the results obtained.

This paper discusses the problem of obtaining selective relay protection in case of accidental grounds on high-tension isolated neutral systems. A relay was developed whose overcurrent element operates on the residual charging current which exists when a ground occurs on such a system, and whose directional element is operated by residual charging current and residual voltage. Two schemes can be employed: One using high-tension potential transformers for energizing the voltage coil of the directional element: the other, which is more complicated but cheaper, making use of low-tension potential transformers. Tests were undertaken on the 140-kv. system of the Consumers Power Co. to determine the effectiveness of this relay system under conditions of arcing and solid grounds. These tests were successful and it was therefore decided to make general use of such relay equipment for the high-voltage isolated neutral system. The relay scheme was put into operation during March, 1926, and the operating records available adequately substantiate the test results.

This paper describes elaborate and severe field tests made on high-speed excitation equipment used with a 5385-kv-a. turbo generator. Complete oscillograms and curves showing the performance of this equipment are included, together with a discussion of the results obtained.

Fundamental considerations governing the coordination of power and communication facilities are presented in this article with particular regard to inductive coupling and power circuit influence. Various factors which must be considered are outlined concisely.

BASIC insulation levels have been defined, and a list of proposed values has been determined by national committees charged with this responsibility. The purpose of this paper is to discuss some of the principles useful in selecting electrical equipment conforming to the requirements of that basic insulation level necessary to assure satisfactory service while operating within the voltage range and under the system conditions expected.

Authors' closure of a paper by J. H. Foote and J. R. North published in the June 1937 issue, pages 677–82, and presented for oral discussion at the insulation co-ordination session of the summer convention, Milwaukee, Wis., June 25, 1937. Previous discussion of this paper appeared in the October 1937 issue, pages 1293–6.

Petersen coils installed on part of a 140-kv transmission system operating with the neutral ungrounde have successfully eliminated a large percentage of interruptions due to line-to-ground faults which occurred on that section. Detailed tests, presented in this paper, also have been made, and indicate many characteristics of the Petersen coil system.

Whereas DNP-KLH primed mouse spleen cells fail to show the high IgG anti DNP levels characteristic of an anamnestic immune response when cultured for 5 days under Mishell-Dutton conditions, we show here that such a response can be observed after 8--10 days in vitro using modified Marbrook culture vessels. The kinetics of this secondary response in vitro resemble that described elsewhere for the adotpive secondary immune response in irradiated recipients, and show that insignificant numbers of IgG PFC can be expected before 6 days of culture. This timing is governed by the maturation state of B cells at the start of culture, and was not accelerated by the addition of recently boosted carrier primed spleen cells. We conclude that the deficit in IgG PFC numbers that characterizes Mishell-Dutton cultures of cells primed 2--4 months previously is due to the shortage of time during which such cultures can maintain lymphocyte division and maturation.

The purified Mr 340,000 glycoprotein component of Epstein-Barr (EB) virus-induced membrane antigen complex incorporated into liposomes was shown to be a potent immunogen in mice. High-titer antisera were induced that (i) are specific for membrane antigen components without absorption, (ii) bind the antigens induced by three different EB virus isolates, and (iii) neutralize the ability of the virus to transform fetal cord blood lymphocytes in vitro. The development of this immunogenic form of purified antigen provides an important step towards a potential subunit vaccine against Epstein-Barr virus infection.

Rabbit antisera to Abelson leukemia virus (A-MuLV)-induced murine lymphomas have been analyzed by absorption with a variety of murine lymphoma lines. Antibody binding to a panel of cell lines and normal lymphocytes was visualized by using hapten-sandwich indirect membrane immunofluorescence. Novel membrane antigens thereby detected are shared between lymphosarcomas, B lymphomas, normal B lymphocytes, and normal membrane immunoglobulin negative (sIg-) bone marrow cells, but are not found on T cells, thymic lymphomas, plasmacytoid lymphomas, or myelomas. The existence of such shared differentiation antigens suggests that sIg- A-MuLV-induced lymphosarcomas may be transformed B cell precursors. Since differences in the expression of these antigens on individual plasma-cytoid lymphoma lines were found, this category of lymphomas may include cells at a variety of differentiation states.

The effectiveness of immunisation of mice, rabbits, and cotton-top tamarins with small amounts of EB virus MA glycoprotein gp340 , incorporated into artificial liposomes, has been compared using various routes of injection with or without additional adjuvants. Liposomes containing gp340 gave specific high titre antibodies after i.p. or i.v. administration, and the addition of lipid A to the liposomes resulted in a significant enhancement of the response. Antibodies generated by the above procedure were virus neutralising and bound gp340 specifically. These findings indicate an advantageous approach for use with a prototype vaccine for the prevention of EB virus infection.

Summary The antigenic specificities of the membrane antigen (MA) complex on three Epstein—Barr (EB) virus-producing cell lines have been compared by complete absorption of an anti-MA antiserum with P3HR-1 cells, followed by testing for residual anti-MA antibody activity against B95-8 and QIMR-WIL cells. Indirect membrane immunofluorescence showed that the absorbed serum, which had lost the capacity to bind P3HR-1 cells, nevertheless gave bright staining on a small proportion of B95-8 cells. SDS-polyacrylamide gel electrophoretic analysis of 125I-labelled MA polypeptides showed that the absorbed serum was able to isolate MA polypeptides from both B95-8 and QIMR-WIL cells, but not from P3HR-1 cells. The results demonstrate that there is substantial sharing of antigenic specificities between the MA determined by three isolates of EB virus, and some antigenic divergence.

We have demonstrated by two separate techniques the formation in vivo of foci of anti-(4-hydroxy-3-iodo-5-nitrophenyl)acetyl (NIP) antibodyforming cells. The initiation and expansion of such foci in the spleens of irradiated mice has been shown to depend on the presence of both hapten-and carrier-primed spleen cell populations. Sensitive methods have been developed to assay the heterogeneity of antibody produced in single anti-hapten foci, usually of less than 1000 plaque-forming cells. Foci from NIP-BSA (bovine serum albumin)-primed spleen cell inocula have been shown to be usually monoclonal. Using mixtures of BSA-primed and NIP-ovalbumin primed spleen cells, the effect of changing the ratio of cooperating cell types upon the homogeneity of antibody in foci has been studied. The results are interpreted as preliminary evidence in favor of a high degree of B cell selection operating during focus initiation. An effect of carrier-primed cell numbers on the size of anti-hapten foci has been detected and some morphological features of foci are described.