Some observations on the temporal variations of size of copepods and some answers to questions on their biology. [Translation from: Internationale Revue der Gesamten Hydrobiologie und Hydrographie 17 99-114, 1927.]

Until now observations on the temporal variation of size of freshwater copepods have not provided much information. Other observers only mention in passing this or that phenomenon from which it is possible to deduct termporal variations. In this study Cyclops strenuus s.l., a freshwater species of fairly wide distribution, is studied in two water bodies. The author studies the systematic, placing of inhabitants described as C. strenuus Fischer in both locations, their annual life cycle, and their annual size variations

Relationship between dielectric properties and critical behavior of the electric birefringence in binary liquid mixtures

We present experimental results on the critical exponent ψEKE describing the divergence of the Kerr constant of binary liquid mixtures near the critical consolute point. We show that the measured value of ψEKE agrees with the theoretical prediction only if the measurement is performed with a mixture of two liquids presenting a small mismatch in the dielectric constant, and that the measured ψEKE grows as the dielectric constant mismatch increases. Such findings are consistent with a recent model which assumes that the elongation of critical fluctations along the direction of the electric field can become so strong that fluctuations in the direction perpendicular to the electric field may cross over from Ising to mean-field behavior

Pretransitional Behavior and Dynamics in Liquid Crystal–Based Nanocolloids

The impact of nanoparticles on phase transitions in liquid crystal (LC)—nanoparticle nanocollids is still little known. This contribution results for dodecylcyanobiphenyl (12CB), pentylcyanobiphenyl (5CB), and hexyl isothiocyanatobiphenyl (6BT) as the LC host with the addition of BaTiO3 barium titanate barium titanate nanoparticles. The latter has a strong impact on the value of dielectric constant, relaxation time, and the discontinuity of the isotropic–mesophase transitions. The first-ever high-pressure studies in such systems are also presented

New challenges for the pressure evolution of the glass temperature

The ways of portrayal of the pressure evolution of the glass temperature (Tg) beyond the dominated Simon-Glatzel-like pattern are discussed. This includes the possible common description of Tg(P) dependences in systems described by dtg/dP>0 and dTg/dP<0. The latter is associated with the maximum of Tg(P) curve hidden in the negative pressures domain. The issue of volume and density changes along the vitrification curve is also noted. Finally, the universal pattern of vitrification associated with the crossover from the low density (isotropic stretching) to the high density (isotropic compression) systems is proposed. Hypothetically, it may obey any glass former, from molecular liquids to colloids

Broadband dielectric studies in linseed oil: Supercriticality and the New Insight into Melting/Freezing Discontinuous Transition

The long-range supercritical changes of dielectric constant, resembling ones observed in the isotropic phase of rod-like liquid crystalline compounds, are evidenced on approaching liquid-solid discontinuous phase transition. The 'supercriticality' can be an additional factor for supporting the unique pro-health properties of linseed oil. It can also be significant for numerous technological applications. The report also reveals properties significant for melting/freezing discontinuous phase transition cognitive puzzle. Broadband dielectric spectroscopy studies revealed long-range premelting (heating from the solid phase) and post-freezing (cooling from the liquid phase) effects with critical-like parametrizations. They can be correlated with the 'grain model' for premelting and its development by the Lipovsky model. The evidence for the post-freezing effect, with the critical-like portrayal, may indicate a specific granular solidification associated with pretransitional fluctuations. Numerous hallmarks of liquid-liquid and solid-solid phase transitions have also been found. Notably, the melting temperature surrounding is related to the minimum and the freezing temperature to the maximum of dielectric loss factor D=tan(delta). Regarding dynamics, three primary relaxation processes have been found. Their changes in subsequent temperature intervals, related to the apparent activation enthalpy, follow critical-like patterns with the same singular temperature. For relaxation times evolution, it leads to optimal parameterizations via the 'critical and activated' equation, recently proposed.Comment: 14 Figures , 15 equation