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Abstract  

Based on a stochastic extension of Karamata’s theory of slowly varying functions, necessary and sufficient conditions are established for weak laws of large numbers for arbitrary linear combinations of independent and identically distributed nonnegative random variables. The class of applicable distributions, herein described, extends beyond that for sample means, but even for sample means our theory offers new results concerning the characterization of explicit norming sequences. The general form of the latter characterization for linear combinations also yields a surprising new result in the theory of slow variation.

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Abstract  

Marcinkiewicz laws of large numbers for φ-mixing strictly stationary sequences with r-th moment barely divergent, 0 < r < 2, are established. For this dependent analogs of the Lévy-Ottaviani-Etemadi and Hoffmann-Jørgensen inequalities are revisited.

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Abstract  

DSC method was used to study thermal stability of nitrocompounds. It was assumed the model to estimate stability of solid phase in which perfect solid phase is totally stable and amorphous-liquid domains connected with impurities decompose according to the kinetic model determined for the liquid phase above the melting point. The influence of sample purity on relative stability, which is k l/k s — ratio of decomposition rate constants in liquid and solid phase, at temperature 20 K below the melting point was predicted. The increase of liquid domains in solid phase causes decrease of k l/k s ratio (relative stability) at chosen temperature.

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Abstract  

The atomic superposition and electron delocalization molecular orbital (ASED-MO) theory was used to calculate structures and relative stabilities of metformin-metal complexes. The relative stabilities and decomposition pathways were discussed in terms of bond order, binding energy and the nature of charge on the central metal atom. The electronic transitions and their energy gaps were also studied. The optimization of the structures shows that the most stable state is distorted from planarity for CoII and NiII complexes.

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Theoretical ecologists have observed chaotic behavior in population models for decades. However, in the past few years, several studies indicate that complex dynamics, including chaos, become less probable in biologically more sophisticated models. For example, the inclusion of either sexual reproduction, population structure or dispersal generally increases stability. These results can explain the difference between the dynamical complexity of most theoretical models and the relative stability found within real time series.

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Journal of Thermal Analysis and Calorimetry
Authors: Luiz Carlos Machado, Marcos Tadeu D’Orlando de Azeredo, Hamilton Perez Soares Corrêa, Jivaldo do Rosário Matos, and Ítalo Odone Mazali

Abstract

This study investigates two lanthanide compounds (La3+ and Sm3+) obtained in water/ethyl alcohol solutions employing the anionic surfactant diphenyl-4-amine sulfonate (DAS) as ligand. Both sulfonates were characterized through IR, TG/DTG (O2 and N2). The thermal treatment of both compounds at 1273 K under air leaves residues containing variable percentages of lanthanide oxysulfide/oxysulfate phases shown by synchrotron high-resolution XRD pattern including the Rietveld analysis. The phase distributions found in the residues evidence the differences in the relative stability of the precursors.

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Abstract  

The antihypertensive drug substance amlodipine besylate crystallizes in two stable crystal forms, an anhydrate and a hitherto unknown monohydrate. Both forms have been characterized by thermal analysis, X-ray powder diffractometry, FTIR- and FT Raman spectroscopy. Moisture sorption- and desorption investigations reveal their unusual physical stability in a broad range of relative humidities. The monohydrate forms an isomorphic dehydrate upon dehydration, which was elucidated by variable temperature X-ray powder diffractometry. Physico-chemical properties as well as relative stabilities of the crystal forms are described and discussed based on a comprehensive analytical identification, and enable an estimation of practical relevance for manufacturing of amlodipine besylate solid dosage forms.

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Journal of Thermal Analysis and Calorimetry
Authors: Veronika Vágvölgyi, M. Hales, W. Martens, J. Kristóf, Erzsébet Horváth, and R. Frost

Abstract  

The understanding of the thermal stability of zinc carbonates and the relative stability of hydrous carbonates including hydrozincite and hydromagnesite is extremely important to the sequestration process for the removal of atmospheric CO2. The hydration-carbonation or hydration-and-carbonation reaction path in the ZnO-CO2-H2O system at ambient temperature and atmospheric CO2 is of environmental significance from the standpoint of carbon balance and the removal of green house gases from the atmosphere. The dynamic thermal analysis of hydrozincite shows a 22.1% mass loss at 247°C. The controlled rate thermal analysis (CRTA) pattern of hydrozincite shows dehydration at 38°C, some dehydroxylation at 170°C and dehydroxylation and decarbonation in a long isothermal step at 190°C. The CRTA pattern of smithsonite shows a long isothermal decomposition with loss of CO2 at 226°C. CRTA technology offers better resolution and a more detailed interpretation of the decomposition processes of zinc carbonate minerals via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. The CRTA technology offers a mechanism for the study of the thermal decomposition and relative stability of minerals such as hydrozincite and smithsonite.

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Abstract  

Thermodynamics of system composed of three possible isomeric dideuteriocyclobutadienes has been studied based on the best available theoretical structural and vibrational parameters. Particular attention is paid to the recently raised question of applicability of the conventional (one term proportional to T3/2) expression for the rotational part of partition functions of the isotopomers at low temperatures T in comparison with more sophisticated approximations viz. containing an additional term proportional to T1/2 or even a correction proportional to T–1/2. Mutual relative stabilities of the isomeric isotopomers are evaluated as well as the isomerism contributions to the system thermodynamics. The three approaches are proved to yield very close results even at very low temperatures. Consequences for structure interplay in isomeric isotopomer sets are discussed.

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Experimental fields of a tobacco breeding station in Hungary at Debrecen were surveyed for potato virus Y (PVY) populations for over a decade. In this field, hundreds of crosses were grown regularly and most of them were lines and hybrids genetically resistant against potato virus Y. From 1993, transgenic tobacco lines bearing the coat protein gene of the new tuber necrotic strain of potato virus Y (NTN) were planted in this experimental field and tested yearly for their virus resistance and the durability of their resistance. During this period, no peculiar strain of PVY was observed, judging from symptoms or using biological tests. In the last five year period the biological observations of PVY isolates were combined with partial molecular analysis. The coat protein gene of PVY from all different isolates collected yearly was cloned, and the most variable 5' ends of the genes were sequenced and compared. All isolates belonged to the new tuber necrotic strain except one, showing the relative stability of the potato virus Y population in an area where genetically different tobacco lines, including transgenic ones, are grown and exposed to natural infection.

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