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Static polarizabilities, α, and static second hyperpolarizabilities, γ, of the rare gas atoms, He–Rn, are investigated employing CCSD(T) calculations and large basis sets. For the lighter atoms, He–Kr, x-aug-cc-pVXZ basis sets were employed in order to test convergence (x = s–5; X = D–6). Further basis sets were employed for He in order to investigate basis set requirements. For the heavier species, effective core potentials (ECPs) are employed, together with a large, flexible valence space. α and γ were obtained by fitting the energies to standard expressions.

On 30 January 2000, following the breach in the tailing dam of the Aurul SA Baia Mare Co., a major spill of about 100,000 m3of cyanide and metal-rich liquid waste was released into the river system near Baia Mare in northwest Romania. The pollutants flowed via different tributaries into the Tizsa (Tisa) river and finally through the Danube river into the Black Sea. Along the way pollutants (especially cyanides) caused rapid death of aquatic organisms and animals living close to the poisoned rivers. Following request from the governments of Romania, Hungary, and the Federal Republic of Yugoslavia, United Nations sent international mission experts to the area of accident. The Czech team of four experts took very active part in this mission. Samples of surface water collected by this team 3 weeks after the accident showed high toxicity in the rivers on the Romanian territory. Due to this impact, water from the Szamos river and a large area of the Tisza river in Hungarian territory was still medially toxic. Improvement of this situation was detected only in downstream areas of the Tisza/Tisa river. The high toxicity of surface water from the locality of the Lapos river upstream of the accident indicated the possibility of toxic pollution from other sources in the area. Aquatic sediments were highly toxic only in the Aurul reservoir and its surrounding area. Rapid decline of their toxicity indicated more limited adverse impact of the “Aurul pollution” in comparison with surface water. From ecotoxicological results it is evident that there is an urgent need to start abatement activities in the Baia Mare area because the possibility of future accidents still exists (this hypothesis was proved by further accidents on 10.3.2000 and the beginning of May 2000).

The Burst Observer and Optical Transient Explo ring System (BOOTES) is considered as a part of the preparations for the ESA's satellite INTEGRAL, and is currently being developed in Spain, in collaboration with two Czech institutions. It makes use of two sets of wide-field cameras 240 kms apart, and two robotic 0.3-m telescopes. The first obser ving station (BOOTES-1) is located in Huelva (Spain) and the first light was obtained in July 1998. During the test phase, it has provided rapid follow-up observations for 5 GRBs detected by the BATSE aboard the CGRO. The system will fully operate in late 1999.

CASSCF+MRCI calculations are performed on NaO(X2Π and A2Σ+) and NaO+(X3Σ-; a1Δ, A3Π, b1Π, c1Σ+ and d1Σ+). Potential energy curves are generated, and from these vibrational frequencies, rotational constants and dissociation energies are derived. Franck–Condon calculations are performed in order to simulate the photoelectron spectra that result from photoionization of the two lowest-lying neutral states, and a comparison to a published spectrum is made. The pertinence of the results to atmospheric chemistry is considered. Finally, the Franck–Condon factors for the absorption/emission spectra of the two cationic transitions, A3Π←X3Σ- and b1Π←a1Δ are calculated.

The geometries and harmonic vibrational frequencies of the Na+·H2O and Na+·CO2complexes are calculated at high levels of ab initio theory (B3LYP, QCISD) using the aug-cc-pVTZ basis set. In addition the binding energies are calculated at the CCSD and CCSD(T) levels of theory using the aug-cc-pVQZ and aug-cc-pV5Z basis sets, with the CCSD(T)/aug-cc-pV5Z results being estimated. These two sets of results are then used to derive the thermodynamic quantities for the clustering reactions, ΔH0and ΔS0. The T-shaped C2vsaddle point of Na+·CO2is briefly investigated.

The photochemical degradation of the homogeneous oxygen-saturated buffered aqueous solutions of sodium heparin salt initiated by the irradiation with medium pressure mercury lamp was compared with the heterogeneous photocatalytic heparin degradation sensitized by titanium dioxide. The obtained results confirmed that UV irradiation of heparin homogeneous aqueous solutions caused negligible changes in the polysaccharidic structure only. The irradiation of heparin in oxygen-saturated physiological saline photosensitized by the TiO2 caused significant changes in the heparin macromolecule. The study of photocatalytic heparin degradation in buffered oxygen-saturated TiO2 suspensions (pH=5–9) ascertained a significant influence of pH on the degradation of heparin. The polymeric chain is predominantly cleaved in the acidic and neutral medium.

Répartition géographique comparée des trois espèces de Rhithrogena du groupe germanica sensu stricto de l'Ouest de l'Europe et de l'Afrique du Nord. Redescription de l'holotype de Rh. soteria Navás, 1917 (imago male, terra typica : l'Espagne) et description de Rh. ryszardi n. sp. (imago male) provenant du Moyen Atlas. Cette dernière est nettement moins orophile que les trois autres espèces de ce genre déjà signalées du Maroc.

Description illustrée de la larve au dernier stade de Baetis ingridae n. sp., rencontrée en Corse. Cette espèce appartient au groupe rhodani.

A general method for constructing permutation-inversion groups and their extensions to molecules containing two coaxial rotors is presented. Symmetry species of the dipole moment, tensor of polarizability, and total angular momentum operator are determined. General infrared and Raman selection rules, symmetry classifications of rotorsional, rotational, and torsional wavefunctions are derived. Theory is illustrated for the H3D+2complex.

Description illustrée de la larve au dernier stade de Baetis cleopatrae n. sp., rencontrée dans le delta du Nil (Egypte). Cette espèce appartient au groupe atrebatinus et présente des affinités morphologiques avec B. balcanicus Müller-Liebenau & Soldán. 1981.

Description illustrée de la larve (au dernier stade) de Baetis punicus n. sp. Cette espèce, rencontrée dans le Nord-Ouest de la Tunisie, appartient au groupe alpinus : elle est comparée à cette dernière espèce et à B. maurus Kimmins.

Description illustrée de la larve au dernier stade et de l'imago mâle de Baetis numidicus n. sp. Cette espèce, rencontrée dans le Nord de l'Algérie, présente à l'état larvaire des affinités morphologiques avec B. gracilis Bogoescu et Tabacaru.

The optimized geometry of PCCP(X1Σg+) was calculated at a number of levels of theory, yielding a best D∞h geometry at the QCISD/6-311G(2d) level with RP-C=1.56Åand RC-C=1.37Å; harmonic vibrational frequencies were also calculated. The four lowest cationic states were studied, allowing the lowest four ionization energies to be obtained. At the G2 level of theory, the first adiabatic ionization energy was calculated to be 9.5 eV. The ordering of the four lowest photoelectron bands is found to be different to NCCN. The adiabatic electron affinity of PCCP is calculated at the G2 level to be 1.1 eV. Finally, the approximate positions of the lowest singlet excited electronic states of the neutral are computed.

High-level ab initio calculations are performed to calculate the global minimum energy structure for NaO2+. At the RCCSD/aug-cc-pV5Z//RCCSD(T)/aug-cc-pVQZ(no g) level of theory it is found that the global minimum is the linear Na–O–O (X3Σ−) state; a C2v(3B1) structure lies 800 cm−1above this. ΔHf298[NaO2+(X3Σ−)] is calculated to be 139.5±2 kcal mol−1, with a dissociation energy, D0(Na+⋯O2)=4.6±0.3 kcal mol−1. ΔHf298[NaO2(X̃2A2)] is derived as −13±3 kcal mol−1, and D0(Na⋯O2)=36±3 kcal mol−1. The adiabatic ionization energy, for the process NaO2+(X3Σ−))←NaO2(X̃2A2) is calculated to be 6.47±0.03 eV.

La larve au dernier stade d'Ecdyonurus rothschildi Navás est figurée et décrite comparativement à celles d'E. aurantiacus (Burmeister) et d'E. dispar (Curtis).

Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 102 SU UMa-type dwarf novae observed mainly during the 2017 season, and characterized these objects. WZ Sge-type stars identified in this study are PT And, ASASSN-17ei, ASASSN-17el, ASASSN-17es, ASASSN-17fn, ASASSN-17fz, ASASSN-17hw, ASASSN-17kd, ASASSN-17la, PNV J20205397$+$2508145, and TCP J00332502$-$3518565. We obtained new mass ratios for seven objects using growing superhumps (stage A). ASASSN-17gf is an EI Psc-type object below the period minimum. CRTS J080941.3$+$171528 and DDE 51 are objects in the period gap, and both showed a long-lasting phase of stage A superhumps. We also summarize the recent advances in understanding of SU UMa-type and WZ Sge-type dwarf novae.

The short stories "The Legend of Wei Li and the Emperor's Palace," "Nonexistent City," and "Dictator and Cards" by Edmundo Paz Soldán are presented, translated from Spanish by Kirk Nesset.

Based on dissections of different aged larvae and adults, the anatomy and developmental changes of the central nervous system, tracheal system, digestive canal and Malpighian tubules, circulatory system, and gonads of Dolania americana are presented. The Malpighian tubules are the most plesiomorphic in the Ephemeroidea; affinities with other families of Ephemeroidea are evident in many characters, some with Potamanthidae and Ephemeridae and some with Palingeniidae and Polymitarcyidae. Derived conditions are found in the alimentary canal (a result of predatory habits) and in characters associated with the shortened head capsule. Ontogeny of the ovaries is unique within Ephemeroptera: only a single egg matures in an ovariole and some ovarioles disintegrate in older and mature larvae. This type of oögenesis results in extremely low fecundity.