2,822 research outputs found
Postsettlement growth of two estuarine crab species, Chasmagnathus granulata and Cyrtograpsus angulatus (Crustacea, Decapoda, Grapsidae): laboratory and field observations
The estuarine grapsid crabs Chasmagnathus granulata and Cyrtograpsus angulatus belong to the most typical and dominant inhabitants of brackish coastal lagoons in southeastern South America. In a combined laboratory and field investigation of juvenile growth, we measured the increase in body size in these species under controlled conditions as well as in field experiments (in Mar Chiquita lagoon, Argentina), seasonal changes in size frequency distribution of a natural population, and growth related changes in selected morphometric traits of male and female juveniles (relations between carapace width, carapace length, propodus height and length of the cheliped, and pleon width). At 24°C, Cy. angulatus grew faster than Ch. granulata; it reached the crab-9 instar (C9; 13 mm carapace width) after 92 days, while Ch. granulata required 107 days to reach the C8 instar (7.4 mm). At 12°C, growth ceased in both species. The pleon begins to show sexual differences in the C5 (Cy. angulatus) and C8 instar (Ch. granulata), respectively, while the chelae differentiate earlier in Ch. granulata than in Cy. angulatus (in C4 vs C6). In the field, growth was maximal in summer, and was generally faster than in laboratory cultures. However, there is great individual variability in size (about 25% even in the first crab instar) and in size increments at ecdysis, increasing throughout juvenile growth. Our data indicate that, in the field, small-scale and short-term variations in feeding conditions, temperature, and salinity account for an extremely high degree of variability in the absolute and relative rates of growth as well as in the time to sexual differentiation
Scratching the Bose surface
This is a `News and Views' article discussing recent proposals for ground
states of many boson systems which are neither superfluids nor Mott insulators.Comment: 4 pages, 1 figur
A helium-3 refrigerator employing capillary confinement of liquid cryogen
A condensation refrigerator suitable for operation in a zero gravity space environment was constructed. The condensed liquid refrigerant is confined by surface tension inside a porous metal matrix. Helium-4 and helium-3 gases were condensed and held in a copper matrix. Evaporative cooling of confined liquid helium-4 resulted in a temperature of 1.4K. Using a zeolite adsorption pump external to the cryostat, a temperature of 0.6 K was achieved through evaporative cooling of liquid helium-3. The amount of time required for complete evaporation of a controlled mass of liquid helium-4 contained in the copper matrix was measured as a function of the applied background power. For heating powers below 18 mW the measured times are consistent with the normal boiling of the confined volume of liquid refrigerant. At background powers above 18 mW the rapid rise in the temperature of the copper matrix the signature of the absence of confined liquid occurs in a time a factor of two shorter than that expected on the basis of an extrapolation of the low power data
Chiral Anomaly and Classical Negative Magnetoresistance of Weyl Metals
We consider the classical magnetoresistance of a Weyl metal in which the
electron Fermi surface possess nonzero fluxes of the Berry curvature. Such a
system may exhibit large negative magnetoresistance with unusual anisotropy as
a function of the angle between the electric and magnetic fields. In this case
the system can support a new type of plasma waves. These phenomena are
consequences of chiral anomaly in electron transport theory.Comment: 4 pages, 2 figure
Сучасні теорії та моделі місцевого самоврядування.
Співак Д.П. Сучасні теорії та моделі місцевого самоврядування. / Д.П. Співак //Актуальні проблеми політики : зб. наук. пр. / гол. ред. С. В. Ківалов ; відп. за вип. Л. І. Кормич. – Одеса : Національний університет "Одеська юридична академія" : Південноукраїнський центр гендерних проблем, 2012. – Вип. 44. – C.112 - 124.In article modern theories and conceptions of understanding essence of local
home rule are considered. One's conceptions are analysed depending on exist-
ing in political reality of models of local home rule. The practical experience of
foreign countries of using different models of local home rule is studied
Phase coherent transport in SrTiO3/LaAlO3 interfaces
The two dimensional electron gas formed between the two band insulators
SrTiO3 and LaAlO3 exhibits a variety of interesting physical properties which
make it an appealing material for use in future spintronics and/or quantum
computing devices. For this kind of applications electrons have to retain their
phase memory for sufficiently long times or length. Using a mesoscopic size
device we were able to extract the phase coherence length, and its temperature
variation. We find the dephasing rate to have a power law dependence on
temperature. The power depends on the temperature range studied and sheet
resistance as expected from dephasing due to strong electron-electron
interactions.Comment: Submitted to Phys. Rev
Принципи формування структури публічної влади на місцевому рівні
Співак Д. П. Принципи формування структури публічної влади на місцевому рівні / Д. П. Співак // Актуальні проблеми політики : зб. наук. пр. / редкол. : С. В. Ківалов (голов. ред..), Л. І. Кормич (заст. голов. ред..), Ю. П. Аленін [та ін.] ; МОНмолодьспорт України ; НУ ОЮА. – Одеса : Фенікс, 2012. – Вип.. 46. – С. 242-248.In this article actual aspects of formation of the public power at local level are
considered. The main principles of formation and the principal directions of their
realization are analyzed
Mesoscopic mechanism of adiabatic charge transport
We consider adiabatic charge transport through mesoscopic metallic samples
caused by a periodically changing external potential. We find that both the
amplitude and the sign of the charge transferred through a sample per period
are random sample specific quantities. The characteristic magnitude of the
charge is determined by the quantum interference.Comment: 4 pages, 2 figure
- …