10,562 research outputs found
Properties of quasi two-dimensional condensates in highly anisotropic traps
We theoretically investigate some of the observable properties of quasi
two-dimensional condensates. Using a variational model based on a
Gaussian-parabolic trial wavefunction we calculate chemical potential,
condensate size in time-of-flight, release energy and collective excitation
spectrum for varying trap geometries and atom numbers and find good agreement
with recent published experimental results.Comment: 7 pages, 4 figure
Thermal induced flow oscillations in heat exchangers for supercritical fluids
Analytical model has been developed to predict possible unstable behavior in supercritical heat exchangers. From complete model, greatly simplified stability criterion is derived. As result of this criterion, stability of heat exchanger system can be predicted in advance
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Implementation issues in product line scoping
Often product line engineering is treated similar to the waterfall model in traditional software engineering, i.e., the different phases (scoping, analysis, architecting, implementation) are treated as if they could be clearly separated and would follow each other in an ordered fashion. However, in practice strong interactions between the individual phases become apparent. In particular, how implementation is done has a strong impact on economic aspects of the project and thus how to adequately plan it. Hence, assessing these relationships adequately in the beginning has a strong impact on performing a product line project right. In this paper we present a framework that helps in exactly this task. It captures on an abstract level the relationships between scoping information and implementation aspects and thus allows to provide rough guidance on implementation aspects of the project. We will also discuss the application of our framework to a specific industrial project
Experimental observation of the 'Tilting Mode' of an array of vortices in a dilute Bose-Einstein Condensate
We have measured the precession frequency of a vortex lattice in a
Bose-Einstein condensate of 87Rb atoms. The observed mode corresponds to a
collective motion in which all the vortices in the array are tilted by a small
angle with respect to the z-axis (the symmetry axis of the trapping potential)
and synchronously rotate about this axis. This motion corresponds to excitation
of a Kelvin wave along the core of each vortex and we have verified that it has
the handedness expected for such helical waves, i.e. precession in the opposite
sense to the rotational flow around the vortices. The experimental method used
to excite this collective mode closely resembles that used to study the
scissors mode and excitation of the scissors mode for a condensate containing a
vortex array was used to determine the angular momentum of the system. Indeed,
the collective tilting of the array that we have observed has previously been
referred to as an `anomalous' scissors mode.Comment: 5 pages, 7 figures to be published in PR
Characterization of Cre recombinase activity for in vivo targeting of adipocyte precursor cells.
The increased incidence of obesity and metabolic disease underscores the importance of elucidating the biology of adipose tissue development. The recent discovery of cell surface markers for prospective identification of adipose precursor cells (APCs) in vivo will greatly facilitate these studies, yet tools for specifically targeting these cells in vivo have not been identified. Here, we survey three transgenic mouse lines, Fabp4-Cre, PdgfRα-Cre, and Prx1-Cre, precisely assessing Cre-mediated recombination in adipose stromal populations and mature tissues. Our data provide key insights into the utility of these tools to modulate gene expression in adipose tissues. In particular, Fabp4-Cre is not effective to target APCs, nor is its activity restricted to these cells. PdgfRα-Cre directs recombination in the vast majority of APCs, but also targets other populations. In contrast, adipose expression of Prx1-Cre is chiefly limited to subcutaneous inguinal APCs, which will be valuable for dissection of APC functions among adipose depots
Variations in the stratospheric ozone field inferred from Nimbus satellite observations
The ultraviolet earth radiance data from the Backscatter Ultraviolet Experiment on Nimbus 4 have been inverted to infer ozone profiles using a single Rayleigh scattering model. Two methods of solution give essentially the same results. Comparisons of these profiles with simultaneous rocket sounding data shows satisfactory agreement at low and middle latitudes. Vertical cross sections of ozone mixing ratio along the orbital tracks indicate that while the gross characteristics of the ozone field above 10 mb are under photochemical control, the influence of atmospheric motions can be found up to the 4 mb level
Evaluation of vaginoscopy for the diagnosis of clinical endometritis in dairy cows
The objective of the study was to evaluate the visual assessment of vaginal
discharge by vaginoscopy for the diagnosis of clinical endometritis (CE) in
dairy cows. In an in vivo trial, inter- and intraobserver repeatability of
vaginoscopic examination (VE) was determined and the effect of transrectal
palpation and experience of the investigator evaluated. Holstein-Friesian cows
(n=380) were examined by vaginoscopy between 21 and 27 d in milk by 3
investigators twice. Vaginal discharge was categorized on a 4-point
classification system (0=clear mucus, 1=mucus containing flecks of pus,
2=discharge containing less than 50% pus, 3=discharge containing more than 50%
pus). Cows with a vaginal discharge score (VDS) of 0 were classified as
healthy, whereas cows with a VDS of 1 to 3 were classified as having CE.
Vaginal discharge score on a scale from 0 to 3 has moderate intra- (Cohen's
kappa coefficient, κ=0.55-0.60) and interobserver (κ=0.44) repeatability. The
prevalence of CE was comparable between the 3 investigators (first VE: 42.6,
34.8, and 38.7; second VE 46.8, 36.9, and 43.7%). Transrectal palpation
(relative risk=0.96-1.03) or experience of the investigator (relative
risk=0.9-1.1) did not affect results of VE. In an in vitro trial, sensitivity
and specificity of visual assessment were determined utilizing 33 images
showing yellow and pink areas in certain percentages as a reference standard.
Pus was represented by yellow areas and the mucosa, including clear mucus, by
pink areas. These images were visually assessed by 30 investigators via
PowerPoint presentation (experiment 1) and by 23 investigators via a simulated
vaginal examination (experiment 2) utilizing the same 4-point classification
system. Sensitivity was 99.6 and 96.3% and specificity was 96.7 and 90.1% in
experiments 1 and 2, respectively. The results provide evidence that a visual
assessment conducted by vaginoscopic examination is not perfect but can be
considered a reasonable measurement of vaginal discharge and is a practical
tool to distinguish healthy from diseased cows
Supplemental Zinc Sulfate Affects Growth Performance of Finishing Heifers
Zinc is an essential mineral required for normal function of more than 300 enzymes in microorganisms, plants, and animals. Zinc-requiring enzymes participate in metabolism of nucleic acids, proteins, and carbohydrates, all of which are essential for growth of cattle. In addition, zinc is necessary for normal development and function of the immune system. The requirement for zinc in finishing cattle diets has been established at 30 ppm (NRC, Nutrient Requirements of Beef Cattle, 2000), though concentrations recommended by consulting nutritionists and feed manufacturers span a far broader range. The purpose of this study was to evaluate the effects of feeding different levels of zinc on feedlot performance and carcass traits of finishing heifers
Electronic integration of the uk-1 international ionosphere satellite
Electronic integration of international ionosphere satellit
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