Metabolic rate measurement system

The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus

A Refutation of Modern Higher Critical Arguments Against the Authenticity of the Davidic Psalms

Setting out to inspect literary productions, the higher critics seek to ascertain their dates, their authors and their value as they themselves may yield the evidence. It is our purpose here, however, to deal only with their considerations advanced in opposition to the conservative view, that David is the author of those Psalms ascribed to him in their titles (seventy-three in all), and in favor of the critical view, advocating a late origin in either exilic or post-exilic times. In classifying their arguments we find that there are essentially three modes of attack used against the authenticity of the Davidic Psalms

Coherent Diffraction Imaging of Single 95nm Nanowires

Photonic or electronic confinement effects in nanostructures become significant when one of their dimension is in the 5-300 nm range. Improving their development requires the ability to study their structure - shape, strain field, interdiffusion maps - using novel techniques. We have used coherent diffraction imaging to record the 3-dimensionnal scattered intensity of single silicon nanowires with a lateral size smaller than 100 nm. We show that this intensity can be used to recover the hexagonal shape of the nanowire with a 28nm resolution. The article also discusses limits of the method in terms of radiation damage.Comment: 5 pages, 5 figure

FUSE observations of G226-29: First detection of the H_2 quasi-molecular satellite at 1150A

We present new FUV observations of the pulsating DA white dwarf G226-29 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). This ZZ Ceti star is the brightest one of its class and the coolest white dwarf observed by FUSE. We report the first detection of the broad quasi-molecular collision-induced satellite of Ly-beta at 1150 A, an absorption feature that is due to transitions which take place during close collisions of hydrogen atoms. The physical interpretation of this feature is based on recent progress of the line broadening theory of the far wing of Ly-beta. This predicted feature had never been observed before, even in laboratory spectra.Comment: Accepted for publication in ApJ Letters; 6 pages, 3 figure

High Resolution Spectroscopy of the Pulsating White Dwarf G29-38

We present the analysis of time-resolved, high resolution spectra of the cool white dwarf pulsator, G29-38. From measuring the Doppler shifts of the H-alpha core, we detect velocity changes as large as 16.5 km/s and conclude that they are due to the horizontal motions associated with the g-mode pulsations on the star. We detect seven pulsation modes from the velocity time-series and identify the same modes in the flux variations. We discuss the properties of these modes and use the advantage of having both velocity and flux measurements of the pulsations to test the convective driving theory proposed for DAV stars. Our data show limited agreement with the expected relationships between the amplitude and phases of the velocity and flux modes. Unexpectedly, the velocity curve shows evidence for harmonic distortion, in the form of a peak in the Fourier transform whose frequency is the exact sum of the two largest frequencies. Combination frequencies are a characteristic feature of the Fourier transforms of light curves of G29-38, but before now have not been detected in the velocities, nor does published theory predict that they should exist. We compare our velocity combination frequency to combination frequencies found in the analysis of light curves of G29-38, and discuss what might account for the existence of velocity combinations with the properties we observe. We also use our high-resolution spectra to determine if either rotation or pulsation can explain the truncated shape observed for the DAV star's line core. We are able to eliminate both mechanisms: the average spectrum does not fit the rotationally broadened model and the time-series of spectra provides proof that the pulsations do not significantly truncate the line.Comment: 24 pages, 9 figures, Accepted for publication in ApJ (June

Testing the implications of a permanent or seasonal marine reserve on the population dynamics of Eastern Baltic cod under varying environmental conditions

In order to test the implications of the establishment of a marine reserve in the Baltic Sea, a spatially disaggregated, discrete time, age-structured model for the Eastern Baltic cod (Gadus morhua callarias L.) stock was constructed. Functional relationships for recruitment and predation mortality were developed by multiple regression analyses. The resultant model output compares well with observed data from the fishery. The model was then applied to simulate stock development over a 50 year time period using different management policies and a variety of environmental conditions. The investigated management policies reduce fishing mortality and range from a moratorium on the Eastern Baltic cod fishery via the establishment of a permanent or a seasonal marine reserve in ICES subdivision 25 to a fishing as usual scenario. The environmental conditions incorporated were based on the size of the reproductive volume (RV) and comprise a best case and a worst case of reproductive conditions, and two more realistic scenarios, where we assumed that a historic series of RV-sizes reoccurs over the simulation period. Our results show a strong dependence of stock dynamics on the environmental conditions. Under prevailing low RV, our model projects stock extinction by the year 2020, if fishing continues as usual. Under the restrictive scenarios, where fishing mortality is reduced either directly or by implementation of a marine reserve, the stock benefits from an increase in stock size and an improved age-structure. A seasonal closure of SD 25 as opposed to a closure of the entire Baltic Sea appears to be sufficient to prevent the Eastern Baltic cod stock from falling below safe biological limits.Baltic cod, management, age-structured model, population dynamics, MPA, environmental variability, reproductive volume

Quasi-molecular Satellites of Lyman Beta in the Spectrum of the DA White Dwarf WOLF 1346

We present new FUV/UV observations of the DA white dwarf Wolf 1346 obtained with the Hopkins Ultraviolet Telescope. The atmospheric parameters of this object are estimated from a fit of model atmospheres to several optical spectra to be Teff = 20000 K, log g = 7.90. From the optical spectrum this star is a normal DA without any indications for chemical elements other than hydrogen. The hydrogen line L beta, however, shows a very unusual shape, with a steep red wing and two absorption features on this wing. The shape is reminiscent of the effects of quasi-molecular line broadening, as observed in L alpha in cooler DA white dwarfs. We show that this is indeed the correct explanation, by identifying 4 quasi-molecular satellites caused through perturbations by the H+ ion (H2+ quasi-molecule). The steep red wing is caused by the exponential decline of the line profile beyond the satellite most distant from the line center at 1078 A.Comment: 11 pages Latex with aaspp4 style, 4 postscript figures, as compressed tar file, ApJ Letters, in pres

Contribution of White Dwarfs to Cluster Masses

I present a literature search through 31 July 1997 of white dwarfs (WDs) in open and globular clusters. There are 36 single WDs and 5 WDs in binaries known among 13 open clusters, and 340 single WDs and 11 WDs in binaries known among 11 globular clusters. From these data I have calculated WD mass fractions for four open clusters (the Pleiades, NGC 2168, NGC 3532, and the Hyades) and one globular cluster (NGC 6121). I develop a simple model of cluster evolution that incorporates stellar evolution but not dynamical evolution to interpret the WD mass fractions. I augment the results of my simple model with N-body simulations incorporating stellar evolution (Terlevich 1987; de la Feunte Marcos 1996; Vesperini & Heggie 1997). I find that even though these clusters undergo moderate to strong kinematical evolution the WD mass fraction is relatively insensitive to kinematical evolution. By comparing the cluster mass functions to that of the Galactic disk, and incorporating plausibility arguments for the mass function of the Galactic halo, I estimate the WD mass fraction in these two populations. I assume the Galactic disk is ~10 Gyrs old (Winget et al. 1987; Liebert, Dahn, & Monet 1988; Oswalt et al. 1996) and that the Galactic halo is ~12 Gyrs old (Reid 1997b; Gratton et al. 1997; Chaboyer et al. 1998), although the WD mass fraction is insensitive to age in this range. I find that the Galactic halo should contain 8 to 9% (alpha = -2.35) or perhaps as much as 15 to 17% (alpha = -2.0) of its stellar mass in the form of WDs. The Galactic disk WD mass fraction should be 6 to 7% (alpha = -2.35), consistent with the empirical estimates of 3 to 7% (Liebert, Dahn, & Monet 1988; Oswalt et al. 1996). (abridged)Comment: 20 pages, uuencoded gunzip'ed latex + 3 postscrip figures, to be published in AJ, April, 199