Simulating a dual beam combiner at SUSI for narrow-angle astrometry

The Sydney University Stellar Interferometer (SUSI) has two beam combiners, i.e. the Precision Astronomical Visible Observations (PAVO) and the Microarcsecond University of Sydney Companion Astrometry (MUSCA). The primary beam combiner, PAVO, can be operated independently and is typically used to measure properties of binary stars of less than 50 milliarc- sec (mas) separation and the angular diameters of single stars. On the other hand, MUSCA was recently installed and must be used in tandem with the for- mer. It is dedicated for microarcsecond precision narrow-angle astrometry of close binary stars. The performance evaluation and development of the data reduction pipeline for the new setup was assisted by an in-house computer simulation tool developed for this and related purposes. This paper describes the framework of the simulation tool, simulations carried out to evaluate the performance of each beam combiner and the expected astrometric precision of the dual beam combiner setup, both at SUSI and possible future sites.Comment: 28 pages, 23 figures, accepted for publication in Experimental Astronomy. The final publication is available at http://link.springer.co

Protecting Your Back: Weight Room Management

Weight room supervision can be a formidable undertaking without the necessary preparations and precautions. Weight room supervisors are much like the Secret Service; that is, no matter what happens, if bad, it is the supervisor\u27s fault. Risk management is more important now than at any point in history. The keys to preventing problems and creating an efficient weight room facility include a highly trained staff and a thoroughly detailed employee manual designed specifically for the weight room

A low cost scheme for high precision dual-wavelength laser metrology

A novel method capable of delivering relative optical path length metrology with nanometer precision is demonstrated. Unlike conventional dual-wavelength metrology which employs heterodyne detection, the method developed in this work utilizes direct detection of interference fringes of two He-Ne lasers as well as a less precise stepper motor open-loop position control system to perform its measurement. Although the method may be applicable to a variety of circumstances, the specific application where this metrology is essential is in an astrometric optical long baseline stellar interferometer dedicated to precise measurement of stellar positions. In our example application of this metrology to a narrow-angle astrometric interferometer, measurement of nanometer precision could be achieved without frequency-stabilized lasers although the use of such lasers would extend the range of optical path length the metrology can accurately measure. Implementation of the method requires very little additional optics or electronics, thus minimizing cost and effort of implementation. Furthermore, the optical path traversed by the metrology lasers is identical with that of the starlight or science beams, even down to using the same photodetectors, thereby minimizing the non-common-path between metrology and science channels.Comment: 17 pages, 4 figures, accepted for publication in Applied Optic

Iowa Farm and Rural Life Poll: 2007 Summary Report

Iowa farm families have both hopes and concerns associated with changes unfolding across the state, especially those related to the rapid development of the “bioeconomy.” The increasing focus on renewable fuels, especially ethanol and biodiesel, brings both great expectations for grain prices and economic growth as well as worries about impacts on the environment and the structure of agriculture. The 2007 Iowa Farm and Rural Life Poll asked questions about these issues and related topics such as land use and future farm plans. The poll was created in 1982 by Iowa State University Extension, the Iowa Agriculture and Home Economics Experiment Station, and the Iowa Department of Agriculture and Land Stewardship. It partners Extension and research programs with the needs of farm families. Data collected on issues of importance to the farming community provide input to local, state, and national leaders in their decision making process. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the poll.https://lib.dr.iastate.edu/extension_communities_pubs/1015/thumbnail.jp

Iowa Farm and Rural Life Poll: 2008 Summary Report

Established in 1982, the Iowa Farm and Rural Life Poll is conducted through a partnership between Iowa State University Extension, the Iowa Agriculture and Home Economics Experiment Station, and the Iowa Department of Agriculture and Land Stewardship. Generally known as “The Farm Poll,” this annual survey effort collects and disseminates information on issues of importance to rural communities across Iowa and the Midwest. The Farm Poll serves to inform the development and improvement of extension and research programs and is used by local, state, and national leaders in their decisionmaking processes. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the poll.https://lib.dr.iastate.edu/extension_communities_pubs/1017/thumbnail.jp

Iowa Farm and Rural Life Poll: 2010 Summary Report

The Iowa Farm and Rural Life Poll is an annual survey that collects and disseminates information on issues of importance to rural communities across Iowa and the Midwest. Conducted every year since its establishment in 1982, the Farm Poll is the longest-running survey of its kind in the nation. Iowa State University Extension, the Iowa Agriculture and Home Economics Experiment Station, the Iowa Department of Agriculture and Land Stewardship, and the Iowa Agricultural Statistics Service are all partners in the Farm Poll effort. The information gathered through the Farm Poll is used to inform the development and improvement of research and extension programs and is used by local, state, and national leaders in their decision-making processes. We thank the many farm families who responded to this year’s survey and appreciate their continued participation in the Farm Poll.https://lib.dr.iastate.edu/extension_communities_pubs/1020/thumbnail.jp

Neural synchrony in cortical networks : history, concept and current status

Following the discovery of context-dependent synchronization of oscillatory neuronal responses in the visual system, the role of neural synchrony in cortical networks has been expanded to provide a general mechanism for the coordination of distributed neural activity patterns. In the current paper, we present an update of the status of this hypothesis through summarizing recent results from our laboratory that suggest important new insights regarding the mechanisms, function and relevance of this phenomenon. In the first part, we present recent results derived from animal experiments and mathematical simulations that provide novel explanations and mechanisms for zero and nero-zero phase lag synchronization. In the second part, we shall discuss the role of neural synchrony for expectancy during perceptual organization and its role in conscious experience. This will be followed by evidence that indicates that in addition to supporting conscious cognition, neural synchrony is abnormal in major brain disorders, such as schizophrenia and autism spectrum disorders. We conclude this paper with suggestions for further research as well as with critical issues that need to be addressed in future studies

A survey of diffuse interstellar bands in the Andromeda galaxy: optical spectroscopy of M31 OB stars

We present the largest sample to-date of intermediate-resolution blue-to-red optical spectra of B-type supergiants in M31 and undertake the first survey of diffuse interstellar bands (DIBs) in this galaxy. Spectral classifications, radial velocities and interstellar reddenings are presented for 34 stars in three regions of M31. Radial velocities and equivalent widths are given for the 5780 and 6283 DIBs towards 11 stars. Equivalent widths are also presented for the following DIBs detected in three sightlines in M31: 4428, 5705, 5780, 5797, 6203, 6269, 6283, 6379, 6613, 6660, and 6993. All of these M31 DIB carriers reside in clouds at radial velocities matching those of interstellar Na I and/or H I. The relationships between DIB equivalent widths and reddening (E(B-V)) are consistent with those observed in the local ISM of the Milky Way. Many of the observed sightlines show DIB strengths (per unit reddening) which lie at the upper end of the range of Galactic values. DIB strengths per unit reddening are found (with 68% confidence), to correlate with the interstellar UV radiation field strength. The strongest DIBs are observed where the interstellar UV flux is lowest. The mean Spitzer 8/24 micron emission ratio in our three fields is slightly lower than that measured in the Milky Way, but we identify no correlation between this ratio and the DIB strengths in M31. Interstellar oxygen abundances derived from the spectra of three M31 H II regions in one of the fields indicate that the average metallicity of the ISM in that region is 12 + log[O/H] = 8.54 +- 0.18, which is approximately equal to the value in the solar neighbourhood

The evidence for automated grading in diabetic retinopathy screening

Peer reviewedPostprin