Healthiness from Duality

Healthiness is a good old question in program logics that dates back to Dijkstra. It asks for an intrinsic characterization of those predicate transformers which arise as the (backward) interpretation of a certain class of programs. There are several results known for healthiness conditions: for deterministic programs, nondeterministic ones, probabilistic ones, etc. Building upon our previous works on so-called state-and-effect triangles, we contribute a unified categorical framework for investigating healthiness conditions. We find the framework to be centered around a dual adjunction induced by a dualizing object, together with our notion of relative Eilenberg-Moore algebra playing fundamental roles too. The latter notion seems interesting in its own right in the context of monads, Lawvere theories and enriched categories.Comment: 13 pages, Extended version with appendices of a paper accepted to LICS 201

Coherent spin dynamics of electrons and holes in semiconductor quantum wells and quantum dots under periodical optical excitation: resonant spin amplification versus spin mode-locking

The coherent spin dynamics of resident carriers, electrons and holes, in semiconductor quantum structures is studied by periodical optical excitation using short laser pulses and in an external magnetic field. The generation and dephasing of spin polarization in an ensemble of carrier spins, for which the relaxation time of individual spins exceeds the repetition period of the laser pulses, are analyzed theoretically. Spin polarization accumulation is manifested either as resonant spin amplification or as mode-locking of carrier spin coherences. It is shown that both regimes have the same origin, while their appearance is determined by the optical pump power and the spread of spin precession frequencies in the ensemble

Bilateral pheochromocytoma and a tumor of the jejunum with neurofibromatosis of type 1

Neurofibromatosis type 1 (NF1) is a hereditary disease with the high frequency of neuroendocrine tumors. This article represents a clinical case of the diagnosed NF1 in a 40-year old patient with the history of bilateral pheocromocytoma and malignant gastrointestinal stromal tumor of the jejunum. Clinical diagnosis NF1 was suspected on the basis of the typical skin manifestations.The timely diagnosis of NF1 has practical significance as it enables physicians persistently search for neuroendocrine lesions in a such cohort of patients

GENE POOL FOR BREEDING MONOGERM TABLE BEET

Results of studying the collection accessions of table beet with different levels of monogermity are presented. Inheritance of this character in the progeny and also its connection with other traits and properties are shown. Accessions with stable expression of monogermity and the possibility of using them in breeding are described. Promising source material for development of heterosis hybrids is recommended

THE GENE POOL FOR TABLE BEET BREEDING (MODERN ASPECTS OF STUDY AND USE)

Background. Modern production imposes increased requirements to the range of used cultivars, so the development of new cultivars and hybrids most adapted to certain soil and climatic conditions is an important task of breeding.Materials and methods. Table beet accessions from the VIR collection originating from 17 countries were chosen as the material for the present research. The accessions were studied at Pushkin and Pavlovsk Laboratories of VIR, at the Genetic Diversity and Plant Bioresources Center of the All-Russian Breeding and Technological Institute of Horticulture and Nursery (VSTISP) and at Maikop Experiment Station, a branch of VIR, according to VIR’s guidelines. esults. The relationships between earliness, bolting resistance, cold tolerance and resistance to black root have been established. The majority of the studied accessions had medium resistance to black root. The cultivars ‘Asmer Detroit 72’ (k-3113, Great Britain), ‘Bravo’ (k-3047, Russia) and ‘Podzimnyaya A-474’ (k-1678, Russia) distinguished by resistance to black root, were also characterized by cold tolerance and stable productivity. The differences in bolting resistance among the accessions were found to depend on their origin. The cultivars from Sweden, Finland and from the Russian Northwest were most resistant to bolting. The early accessions ‘Perfected Detroit Dark Red’ (k-1815, Canada), ‘Bikor’ (k-2873, the Netherlands), ‘Severnyshar’ (k-1586, Russia) and ‘Polyarnaya ploskaya’ (k-1585, Russia) were characterized by high rates of the vegetative mass growth and bolting resistance. It was noted that the absolutely monogermic varieties have lower ripening rates, productivity, and resistance to bolting, compared to the multigerm ones, but have similar chemical composition indicators and root quality. Accessions with a wide distribution area that maintain high root productivity at 115–120% to the reference in different climatic conditions have been identified.Conclusions. The research has resulted in the identification of table beet accessions characterized by a complex of biological and economically important traits. The relationships between earliness, resistance to bolting and cold tolerance have been revealed. Genetic sources of monogermicity, bolting resistance, cold tolerance, black root resistance and high root quality are recommended for the use in breeding

Anomalous Thermal Stability of Metastable C_20 Fullerene

The results of computer simulation of the dynamics of fullerene C_20 at different temperatures are presented. It is shown that, although it is metastable, this isomer is very stable with respect to the transition to a lower energy configuration and retains its chemical structure under heating to very high temperatures, T ~ 3000 K. Its decay activation energy is found to be E_a ~ 7 eV. Possible decay channels are studied, and the height of the minimum potential barrier to decay is determined to be U = 5.0 eV. The results obtained make it possible to understand the reasons for the anomalous stability of fullerene C_20 under normal conditions.Comment: Slightly corrected version of the paper submitted to Phys. Solid Stat