1,848 research outputs found
Current Views Concerning the Liquid State
Investigation of ether in the region of the critical point by the x-ray diffraction methods leads to a new conception of the liquid state. A review is made of authoritative views on the subject and these views discussed in the light of new evidence obtained by x-ray methods. It appears that existing definitions of the liquid state are not adequate and should be supplanted by ones more in conformity with the facts
The Dependence of Cybotactic Groups on Specific Volume
Additional x-ray diffraction data have been taken on ethyl ether in the region of the critical point. (Spangler, Abstract 24, Phys. Rev. 42, p 907, 1932) Series of diffraction curves at pressures of 39.2, 44.1, 49, and 55 kg/cm with temperatures ranging up to 235°C show, as in previous work, that the cybotactic groupings depend more on specific volume than on temperature. At each of the above pressures, the indications of groups disappear at about the critical specific volume regardless of the higher temperatures at higher pressures. The ionization currents were measured with a direct deflection amplifier employing an FP-54 tube instead of the customary electrometer. With this arrangement data could be taken much more rapidly and the fidelity of the results is, in the limit of observation, the same
Results of tests OA26 and IA16 in the NASA/ARC 3.5-foot hypersonic wind tunnel on an 0.015-scale model (36-OTS) of the space shuttle configuration 140A/B to obtain pressures for venting analysis
Tests were conducted, from November 15 to December 4, 1973, to obtain surface pressure data on an 0.015-scale replica of the Space Shuttle Vehicle 4. Data were obtained at Mach numbers of 5.3, 7.4, and 10.3, to support the venting analysis for both launch and entry conditions. These tests were the final tests in a series covering a Mach number range from 0.6 to 10.3. The model was instrumented with pressure orifices in the vicinity of the cargo bay door hinge and parting lines, and on the side of the fuselage at the crew compartment, and below the orbital maneuvering system pods at the aft compartment. The model was tested at angles of attack and sideslip consistent with expected divergencies from the nominal trajectory
Four Stokes parameter radio frequency polarimetry of a flare from AD Leonis
Observations of the four Stokes parameters of a 430 MHz flare from the UV Ceti-type star AD Leonis are presented. The maximum amplitude of the event was 0.52 flux units and the durations at one-half and one-tenth maximum were 12 and 40 seconds, respectively. The degree of circular polarization at maximum intensity was approximately 56 percent and was later observed to be as high as 92 percent. Linear polarization was also observed at a level of about 21 percent at flare maximum which allowed an upper limit of 440 radians - sq m to be placed on the rotation measure
Fruit Pest Events and Phenological Development According to Accumulated Heat Units
Mammals are "warm-blooded" and develop at a constant
rate regardless of the environmental temperature,
because they are able to maintain an internal temperature
that allows their biochemical reactions to progress normally.
Insects, which are "exothermic" (the same temperature as
their environment; there is no such thing as "cold-blooded"),
do not generate body heat, and are therefore limited in their
development to periods of favorable external temperature.
Below a certain temperature, which varies among species,
the insect's biochemical reactions cannot proceed, and
development stops. This temperature is known as the
insect's developmental threshold ordevelopmental base.
By charting the ambient temperature, it is possible to keep
track of insect development, which is directly proportional to
the amount of time accumulated above the developmental
threshold (up to some maximum not often reached during
the season). We arbitrarily divide this time into heat units,
or degree-days (DD)
Computer Simulation of Cytoskeleton-Induced Blebbing in Lipid Membranes
Blebs are balloon-shaped membrane protrusions that form during many
physiological processes. Using computer simulation of a particle-based model
for self-assembled lipid bilayers coupled to an elastic meshwork, we
investigated the phase behavior and kinetics of blebbing. We found that blebs
form for large values of the ratio between the areas of the bilayer and the
cytoskeleton. We also found that blebbing can be induced when the cytoskeleton
is subject to a localized ablation or a uniform compression. The results
obtained are qualitatively in agreement with the experimental evidence and the
model opens up the possibility to study the kinetics of bleb formation in
detail.Comment: To appear in Physical Review
Animal board invited review: Practical applications of genomic information in livestock
Access to high-dimensional genomic information in many livestock species is accelerating. This has been greatly aided not only by continual reductions in genotyping costs but also an expansion in the services available that leverage genomic information to create a greater return-on-investment. Genomic information on individual animals has many uses including (1) parentage verification and discovery, (2) traceability, (3) karyotyping, (4) sex determination, (5) reporting and monitoring of mutations conferring major effects or congenital defects, (6) better estimating inbreeding of individuals and coancestry among individuals, (7) mating advice, (8) determining breed composition, (9) enabling precision management, and (10) genomic evaluations; genomic evaluations exploit genome-wide genotype information to improve the accuracy of predicting an animal’s (and by extension its progeny’s) genetic merit. Genomic data also provide a huge resource for research, albeit the outcome from this research, if successful, should eventually be realised through one of the ten applications already mentioned. The process for generating a genotype all the way from sample procurement to identifying erroneous genotypes is described, as are the steps that should be considered when developing a bespoke genotyping panel for practical application
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