Structure,superconductivity and magnetism of new rare earth-rhodium silicides RE2Rh3Si5 of U2Co3Si5-type

New ternary silicides RE₂Rh₃Si₅ (RE = Y, La, Nd, Sm, Gd, Tb, Dy, Ho, Er) have been prepared. They crystalize in the U₂Co₃Si₅-type structure. Only the silicides containing the diamagnetic rare earths Y and La show a superconducting transition at T_Cr = 4.4 ± 0.2K and T_Cr = 2.7 ± 0.1K respectively, those with magnetic rare earths order antiferromagnetically at low temperature.     

Light-dependent effects of alpha-terthienyl in eggs,larvae, and pupae of mosquitoAedes aegypti

Alpha-terthienyl is toxic toAedes aegypti larvae in the dark, but its activity is much enhanced in the presence of ultraviolet light. The development of first-instar larvae treated with alpha-terthienyl and ultraviolet light was followed until the emergence of adults. The LC₅₀ value for first instars was about 0.002 ppm. Practically all the larvae which survived 24 hr reached adulthood. Fourth-instar larvae were also sensitive to photochemical treatment. When their development into adults was followed, the LC₅₀ value was 0.45 ppm. Contrary to earlier reports, alpha-terthienyl was also phototoxic in pupae, but not when the adults were about to emerge. The LC₅₀ value was ca. 0.06 ppm for pupae which were 1 or 2 days old. This is the first example where the activity of a photoinsecticide has been demonstrated in pupae. Alpha-terthienyl did not affect the hatching of eggs.     

Organizational quality on the Rey-Osterrieth and Taylor Complex Figure Tests: A new scoring system.

A new system for measuring organizational quality on the Complex Figure Test (A. Rey, 1942; L. B. Taylor, 1969) is described. This system extends the traditional use of the test as a measure of constructional ability and figural memory. The new system is easy to learn, quick to score, and shows very good interrater reliability. Organizational quality was found to correlate moderately with copy accuracy, half-hour recall, and percentage retained. In an initial application of the system (N?=?63), organizational quality of the Rey-Osterrieth Complex Figure successfully discriminated between symptomatic (those with AIDS or AIDS-related complex) and asymptomatic Ss positive for human HIV, but organizational quality ratings of the Taylor figure did not. Results suggest that the Taylor figure is easier to organize than the Rey-Osterrieth. Thus, the Taylor figure may not be an appropriate alternative to the Rey-Osterrieth for the assessment of organizational quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct charging of thin slabs of a Ti-microalloyed low carbon steel for cold forming

With a near-net-shape continuous-casting simulator and the hot deformation simulator Wumsi, laboratory simulation tests have been performed to determine the final microstructure and the mechanical properties of a Ti-microalloyed low carbon steel for cold forming, produced in the process of direct charging of thin slabs. For two initial specimen thicknesses (45 and 25mm) restricted values of total strain ?_∑ were available to improve the coarse as-cast microstructure. In a series of deformation schedules ?_∑ was divided systematically into two components: an austenite grain-refining strain ?_γ–GF (above the recrystallization-stop-temperature T_RS) and an austenite strengthening strain ?_γ–s (below T_RS). After hot deformation accelerated cooling with simulated coiling was employed. It was found that the direct charging process guarantees a more complete dissolution of Ti(C,N) and so an intensifying effect of Ti-microalloying in comparison to a conventional cold charging. Structure refinement by rolling performed predominantly in the temperature region of non-recrystallized austenite (increasing ?_γ–s) leads to better hot strip strength and improved low temperature toughness properties accompanied with a slight deterioration of uniform elongation.     

Comments on "Controllability, Observability and Structural Identifiability of Multi Input and Multi Ouput Biological Compartmental Systems"

In a recent paper,1 a criterion of structural identifiability for a system of biological compartments was given. Two comments are here made which show, in particular, that the proposed criterion is a necessary but not a sufficient condition for a finite number of solutions (not necessarily just one).     

Etude du systeme RbFErF3

The phase diagram of the RbF-ErF₃ system shows the existence of the four compounds Rb₃ErF₆, Rb₂ErF₅, RbEr₃F₁₀ and RbEr₂F₇. We report the X-ray powder data for the three first ones and X-ray single crystal data for RbEr₂F₇.     

Modelling of heat transfer in a climbing-film evaporator: III. Application to an industrial evaporator

A mathematical model developed to predict the heat transfer in a single-tube climbing-film evaporator is used to evaluate the performance of a three-stage shell-and-tube evaporator for concentrating 5000 kg h^?1 of pineapple juice from 13·5 to 62° Brix.     

Les distributions statistiques fortement variables. Applications aux télécommunications

Part two is devoted to the tests of hypothesis as well as to the most current statistical processes in the field of telecommunications: normal, negative exponential, lognormal, the latter having the likelihood function with the highest value at the maximum of likelihood. Analysing samples with a size under 1.000 requires a powerful test (Geary test) and a high grade sampling (e.g. stratification into classes of equal value). Most of the statistical populations are of mixed structure with a dispersion of same order of magnitude as the parent population. For the sake of efficiency, it is necessary to consider sub-populations with very high variability well modelled through lognormal laws. The standard deviations of the logarithm of the random variable have constant magnitudes for user’s behaviour or traffic growth. The higher values are preponderant as far as management dynamics is concerned.     

Interactions magnetiques intra- et interclusters dans les pentafluorures RuF5 et OsF5

The nature of the magnetic interactions in RuF₅ and OsF₅ has been investigated using neutron diffraction and magnetic measurements under high applied fields. RuF₅ and OsF₅ are magnetically ordered at respectively T_N = 5 and 6 K. The magnetic structures have been determined. A model based on isolated tetranuclear clusters M₄F₂₀ (M = Ru or Os) has been applied to explain the magnetic behavior above the Néel temperature. The intracluster exchange interactions are antiferromagnetic. The fitting of the magnetization data leads to an exchange constant of $\text{J}\text{k}\text{= ?7.7}\text{K}$ for RuF₅, in good agreement with that calculated from the thermal variation of the magnetic susceptibility.