Airborne Conical Antenna Arrays Ponomarev, L. I.; Vasin, A. A.; Terekhin, O. V. ...
Journal of communications technology & electronics,
10/2020, Volume:
65, Issue:
10
Journal Article
Peer reviewed
The study presents an algorithm and the results of analysis of the sum-and-difference directional characteristics of an airborne conical antenna arrays (AAs) of slot radiators located on the ...conductive surface of the cone. It is shown that the maximum directivity of such antennas in the radiation mode and the steepness of the difference radiation pattern (in the
E
-plane) in the receive mode for pointed cones can significantly exceed similar parameters of the equivalent planar aperture.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular
CP violation in
Ξ
and
Λ
hyperon decays with a sensitivity of
...10
-
4
. Intense charged secondary beams were produced by 800
GeV/
c protons and momentum selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in 12 months of data-taking.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The self-fertilizing mangrove rivulus,
Kryptolebias marmoratus, can produce homozygous ‘clonal’ offspring and are highly tolerant of severe environmental conditions, including air exposure (emersion) ...for weeks at a time. We tested the following hypotheses: (1) individual fish that voluntarily emerse more possess gill and skin features better suited for life on land than fish that emerse less often, and (2) individual differences in emersion tendencies cause these morphological changes. We predicted that individuals spending more time in air would have a reduced gill surface area (shorter, thicker gill lamellae and well developed interlamellar cell masses (ILCM)) and a thicker cutaneous epidermis compared to fish preferring to remain in water. These differences were predicted to disappear if fish were prevented from emersing and predicted to reappear if fish were once again allowed to emerse. Fish were videorecorded for 7 days while voluntarily moving between aquatic and terrestrial habitats to determine individual emersion tendencies. We prevented a subset of fish from emersing for 7 days, and then allowed a subset of these fish to emerse for a final 7 days. We found that individual fish spent anywhere from 0 to 78% of the time emersing. Emersion time was positively correlated with gill ILCM height, but not with any other morphological feature. There was no relationship between ILCM height and emersion time after fish were prevented from emersing for 7 days, but this relationship reappeared when fish were once again able to emerse. These results indicate that genetically identical
K. marmoratus show highly variable behavioural phenotypes that influence gill remodelling. Fish that voluntarily spend more time emersed reduce gill surface area, a modification that may limit branchial water loss and provide support for gill lamellae. This is the first report of respiratory morphologies linked to variation in behavioural phenotype.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
7.
Novel effects of nitric oxide Davis, K. L.; Martin, E.; Turko, I. V. ...
Annual review of pharmacology and toxicology,
01/2001, Volume:
41, Issue:
1
Journal Article
Peer reviewed
Nitric oxide (NO), a simple free radical gas, elicits a surprisingly wide range of physiological and pathophysiological effects. NO interacts with soluble guanylate cyclase to evoke many of these ...effects. However, NO can also interact with molecular oxygen and superoxide radicals to produce reactive nitrogen species that can modify a number of macromolecules including proteins, lipids, and nucleic acids. NO can also interact directly with transition metals. Here, we have reviewed the non--3',5'-cyclic-guanosine-monophosphate-mediated effects of NO including modifications of proteins, lipids, and nucleic acids.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Laboratory-based research dominates the fields of comparative physiology and biomechanics. The power of lab work has long been recognized by experimental biologists. For example, in 1932, Georgy ...Gause published an influential paper in Journal of Experimental Biology describing a series of clever lab experiments that provided the first empirical test of competitive exclusion theory, laying the foundation for a field that remains active today. At the time, Gause wrestled with the dilemma of conducting experiments in the lab or the field, ultimately deciding that progress could be best achieved by taking advantage of the high level of control offered by lab experiments. However, physiological experiments often yield different, and even contradictory, results when conducted in lab versus field settings. This is especially concerning in the Anthropocene, as standard laboratory techniques are increasingly relied upon to predict how wild animals will respond to environmental disturbances to inform decisions in conservation and management. In this Commentary, we discuss several hypothesized mechanisms that could explain disparities between experimental biology in the lab and in the field. We propose strategies for understanding why these differences occur and how we can use these results to improve our understanding of the physiology of wild animals. Nearly a century beyond Gause's work, we still know remarkably little about what makes captive animals different from wild ones. Discovering these mechanisms should be an important goal for experimental biologists in the future.
The notion of temperature in many body elementary particle processes is in a common use for decades. Thermal models have become simple and universal effective tools to describe particle ...production—not only in high energy heavy ion collisions but also in high energy elementary particle collisions. We perform a critical analysis of the temperature concepts in such processes. Although the temperature concept is a very useful tool, nevertheless it should be used with the care, taking into account that usually it is just model dependent fitted parameter.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Fishes acclimated to hypoxic environments often increase gill surface area to improve O
uptake. In some species, surface area is increased via reduction of an interlamellar cell mass (ILCM) that ...fills water channels between gill lamellae. Amphibious fishes, however, may not increase gill surface area in hypoxic water because these species can, instead, leave water and breathe air. To differentiate between these possibilities, we compared wild amphibious mangrove rivulus
from two habitats that varied in O
availability - a hypoxic freshwater pool versus nearly anoxic crab burrows. Fish captured from crab burrows had less gill surface area (as ILCMs were enlarged by ∼32%), increased rates of normoxic O
consumption and increased critical O
tension compared with fish from the freshwater pool. Thus, wild mangrove rivulus do not respond to near-anoxic water by decreasing metabolism or increasing O
extraction. Instead, fish from the crab burrow habitat spent three times longer out of water, which probably caused the observed changes in gill morphology and respiratory phenotype. We also tested whether critical O
tension is influenced by genetic heterozygosity, as
is one of only two hermaphroditic vertebrate species that can produce both self-fertilized (inbred) or out-crossed (more heterozygous) offspring. We found no evidence for inbreeding depression, suggesting that self-fertilization does not impair respiratory function. Overall, our results demonstrate that amphibious fishes that inhabit hypoxic aquatic habitats can use a fundamentally different strategy from that used by fully aquatic water-breathing fishes, relying on escape behaviour rather than metabolic depression or increased O
extraction ability.
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