The orbit of the Cepheid AW Per

An orbit for the classical Cepheid AW Per was derived. Phase residuals from the light curve are consistent with the light-time effect from the orbit. The companion was studied using IUE spectra. The flux distribution from 1300 to 1700 A is unusual, probably an extreme PbSi star, comparable to a B7V or B8V star. The flux of the composite spectrum from 1200 A through V is well matched by F7Ib and B8V standard stars with Delta M(sub upsilon) = 3(m) multiplied by 1. The mass function from the orbit indicates that the mass of the Cepheid must be greater that 4.7 solar mass if it is the more massive component. A B7V to B8V companion is compatible with the 1 sigma lower limit (3.5 solar mass) from the mass function. This implies that the Cepheid has the same mass, but the large magnitude difference rules this out. It is likely that the companion is itself a binary

Irrigation and water resources in the 1990's

Presented at Irrigation and water resources in the 1990's: proceedings from the 1992 national conference held on October 5-7, 1992 in Phoenix, Arizona.An interceptor canal will be constructed near the end of eight laterals to collect and transport operational discharge and returned farm deliveries to a reservoir for temporary storage. The water will then be pumped over to an adjacent canal system for delivery. This project is being funded by the Imperial Irrigation District - Metropolitan Water District of Southern California (IID-MWD) Water Conservation Agreement. This paper describes the planning process for the project

Macho Proper Motions From Optical/Infrared Photometry

Optical/infrared photometry can double the number of proper motion measurements of Massive Compact Objects (MACHOs) relative to single band photometry. The proper motion of a MACHO can be measured by finding the ratio $q$ of the (known) radius of the source star to the Einstein radius of the MACHO, $q=\theta_s/\theta_e$. A classic method for doing this is to look for the effect on the light curve of the finite size of the source. A modification of this method proposed by Witt (1995) is to look for color changes in the light curve due to the fact that the limb darkening of the source is different in different bands. We demonstrate that the ``classical'' method is not feasible unless the MACHO actually transits the source: if the MACHO passes at say 1.5 source radii, there is still a sizable $\sim 5\%$ effect, but the light curve cannot be distinguished from point-source light curves with different parameters. However, color measurements in $V$ $(0.55\,\mu$m) and $H$ $(1.65\,\mu$m) reduce the errors by a factor $\sim 120$ and permit proper motion measurements at impact parameters of up to 2 source radii. Color maps in $V-H$ are also useful in the detection of planetary systems. Giant stars have a ``red ring'' in such maps. A planet which transits this ring gives rise to a distinctive signature which can help in the measurement of the planetary system's proper motion.Comment: 15 pages, uuencoded postscript, includes 3 figures. Also available at http://www.physics.mcmaster.ca/Welch_Preprints/OIR_mpm.p

Neuromuscular control of wingbeat kinematics in Anna's hummingbirds (Calypte anna)

Hummingbirds can maintain the highest wingbeat frequencies of any flying vertebrate – a feat accomplished by the large pectoral muscles that power the wing strokes. An unusual feature of these muscles is that they are activated by one or a few spikes per cycle as revealed by electromyogram recordings (EMGs). The relatively simple nature of this activation pattern provides an opportunity to understand how motor units are recruited to modulate limb kinematics. Hummingbirds made to fly in low-density air responded by moderately increasing wingbeat frequency and substantially increasing the wing stroke amplitude as compared with flight in normal air. There was little change in the number of spikes per EMG burst in the pectoralis major muscle between flight in normal and low-density heliox (mean=1.4 spikes cycle^(–1)). However the spike amplitude, which we take to be an indication of the number of active motor units, increased in concert with the wing stroke amplitude, 1.7 times the value in air. We also challenged the hummingbirds using transient load lifting to elicit maximum burst performance. During maximum load lifting, both wing stroke amplitude and wingbeat frequency increased substantially above those values during hovering flight. The number of spikes per EMG burst increased to a mean of 3.3 per cycle, and the maximum spike amplitude increased to approximately 1.6 times those values during flight in heliox. These results suggest that hummingbirds recruit additional motor units (spatial recruitment) to regulate wing stroke amplitude but that temporal recruitment is also required to maintain maximum stroke amplitude at the highest wingbeat frequencies

Dynamics of the Intermediate-Age Elliptical LMC Cluster NGC 1978

In this paper we investigate the internal dynamics of the LMC cluster NGC 1978 through the use of Photometric (CCD images) and kinematic (stellar radial velocities) data. We apply a variety of dynamical models to this data, including multi-mass King-Michie models and rotating and non-rotating oblate spheroid models. We discuss the cluster mass-to-light ratio and place constraints on the cluster mass function.Comment: 36 pages (plus 8 figures available through anonymous FTP, see below

DYNAMICS OF THE GALACTIC GLOBULAR CLUSTER NGC 3201

B,V CCD frames have been used to derive surface brightness profiles for NGC 3201 out to ~18 arcmin. A total of 857 radial velocities with median precision ~1 km/s for 399 member giants have been used to trace the velocity dispersion profile out to 32' (the approximate tidal radius from fits of single-mass, isotropic King-Michie models to the cluster surface brightness profiles). The median difference in radial velocity for stars on either side of an imaginary axis moved through the cluster in 1 degree steps shows a significant maximum amplitude of 1.22+/-0.25 km/s. We discuss possible explanations of this result, including: (1) cluster rotation; (2) preferential stripping of stars on prograde orbits near the limiting radius; (3) the projection of the cluster space velocity onto the plane of the sky and (4) a slight drift in the velocity zero point. It is difficult to identify the primary cause of the observed velocity field structure unambiguously, and we suspect that all of the above processes may play a role. The B,V surface brightness profiles and radial velocities have been modeled with single- & multi-mass King-Michie models and nonparametric techniques. The density and M/L profiles show good agreement over 1.5<R<10 pc, and both approaches suggest a steady rise in M/L with distance from the cluster center. Due to the low cluster luminosity, we are unable to place useful constraints on the anisotropy of the velocity dispersion profile, though the global mass-to-light ratio is well-constrained by the models as ~2.0 +/-0.2 for the multi-mass and nonparametric models, compared to ~ 1.65 +/-0.15 for models having equal-mass stars. Our best-fit, multi-mass models have mass function slopes of x~0.75 +/-0.25, consistent with findings that mass function depends on the position relative to the potential of the Galaxy.Comment: uuencoded compressed Postscript, 59 pages including 10 figures. Also available at http://www.dao.nrc.ca/DAO/SCIENCE/science.htm

The Variable Stars and Blue Horizontal Branch of the Metal-Rich Globular Cluster NGC 6441

We present time-series VI photometry of the metal-rich ([Fe/H] = -0.53) globular cluster NGC 6441. Our color-magnitude diagram shows that the extended blue horizontal branch seen in Hubble Space Telescope data exists in the outermost reaches of the cluster. The red clump slopes nearly parallel to the reddening vector. A component of this slope is due to differential reddening, but part is intrinsic. The blue horizontal branch stars are more centrally concentrated than the red clump stars. We have discovered about 50 new variable stars near NGC 6441, among them eight or more RR Lyrae stars which are very probably cluster members. Comprehensive period searches over the range 0.2-1.0 days yielded unusually long periods (0.5-0.9 days) for the fundamental pulsators compared with field RR Lyrae of the same metallicity. Three similar long-period RR Lyrae are known in other metal-rich globulars. With over ten examples in hand, it seems that a distinct sub-class of RR Lyrae is emerging. The observed properties of the horizontal branch stars are in reasonable agreement with recent models which invoke deep mixing to enhance the atmospheric helium abundance, while they conflict with models which assume high initial helium abundance. The light curves of the c-type RR Lyrae seem to have unusually long rise times and sharp minima. Reproducing these light curves in stellar pulsation models may provide another means of constraining the physical variables responsible for the anomalous blue horizontal branch extension and sloped red clump observed in NGC 6441.Comment: 30 pages plus 6 EPS and 6 JPEG figures; uses AAS TeX. Accepted by the Astronomical Journal. Minor changes include computing He abundance, modifications to Figs 1 and 8, and expansion on idea that blue HB stars may be produced in binarie

Inertia and managerial intentionality: extending the Uppsala model

The Uppsala Internationalization Process Model is the most cited model within the field of international business. However, even with its most recent formulation, the model is predicated on a key set of assumptions about the limiting and releasing mechanisms in a ‘change of state’ decision. The model assumes that uncertainty, risk, lack of trust, and lack of awareness of opportunities are the main constraints, and that the accumulation of experiential knowledge, trust, and market commitment are the main releasing factors that allow a firm to overcome those constraints and progress to a higher state of commitment. We argue that the preceding view may be excessively narrow, and that inertia and managerial intentionality may also play a role as critical limiting and releasing mechanisms, respectively. This development implies that the passage of time and experiential learning may not always have a positive impact on firm internationalization. The extended model proposed in this paper highlights the role of the manager, and brings a contingent element to the model, thus broadening its applicability by providing new insights on issues typically considered outside the realm of the Uppsala model, such as rapidly internationalizing firms, regionalization, mode inertia and mode skipping

Mentoring Academy

White paper proposing creation of IUPUI Mentoring AcademyIUPUI’s Strategic Plan, “Our Commitment to Indiana and Beyond,” places faculty and staff talent development among its highest priorities. The goal is to position IUPUI as an “employer of choice” through a number of actions, including improved workplace culture and communication and more robust developmental opportunities across all categories of faculty and staff. Based on feedback received during the strategic planning process, the completed implementation plan will articulate career paths for staff and faculty, identify and inventory a variety of campus resources, and provide relevant professional development opportunities. In addition, policies and procedures will be created to foster work/life balance and flexibility for IUPUI’s entire workforce. In order for IUPUI to reach the level of excellence expected in the plan, we must be assured that our investment in faculty will lead to greater success and productivity. The Mentoring Academy goals and objectives outlined below provide a means to engage faculty within each school and create a pathway for achievement of successful mentoring