Specific interplanetary conditions for CIR-, Sheath-, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis

The comparison of specific interplanetary conditions for 798 magnetic storms with Dst < -50 nT for the period 1976-2000 was made on the basis of the OMNI archive data.We categorized various large-scale types of solar wind as interplanetary drivers of storms: corotating interaction region (CIR), Sheath, interplanetary CME (ICME) including magnetic cloud (MC) and Ejecta, separately MC and Ejecta, and "Indeterminate" type. The data processing was carried out by the method of double superposed epoch analysis which uses two reference times (onset of storm and the minimum Dst index) and make a re-scaling of main phase of storm a such way that after this transformation all storms have equal durations of main phase in new time reference frame. This method reproduced some well-known results and allowed us to obtain some new results. Specifically, obtained results demonstrate high importance of Sheath in generation of magnetic storms as well as a significant differences in properties of MC and Ejecta and in their geoeffectiveness.Comment: 21 pages, 9 figures, 1 table, submitted to J. of Advances in Space Research on 29 July, 2009 for Special Issue "Space Weather Advances

The impact of temperature patterns during storage of Scots pine and Norway spruce seeds on their germination and fungal infection rates

Relevance of the study. One of the ways to maintain the genetic diversity of forest-forming species is to preserve highquality seed material ex situ. However, the relationship between the diversity of pathogenic mycobiota and the duration and methods of forest tree seed storage remains underexplored. The results of research into this problem can be used in forest seed production and forest phytopathology.Materials and methods. For our study we used seeds of Рinus sylvestris L. and Picea abies (L.) Karst. of the orthodox type, harvested in the period of 1996–2011 and stored under different temperatures: +20°С, +4°С, –18°С, and in liquid nitrogen vapor (–182°С) since 2011. Prior to their storage, seed samples were dried to a moisture content of 4.2–4.4% and hermetically packed. Seed germination was tested before and after three, five and eight years of storage, following GOST 13056.6-97 standards. The level of seed infection and the composition of pathogenic fungi were assessed.Results. After eight years of storage at +20°С, pine and spruce seed germination capacity decreased by 13–60%, depending on the year of harvesting. Seed storage at –18°С and –182°С allowed us to prevent seed infection and preserve seed viability. In most cases, the germination energy and germination capacity were negatively correlated with the level of seed infection. The diversity of pathogenic (mold) fungi on the surface of seeds was represented by ten genera; the most common were saprotrophs: Aspergillus P. Micheli, Penicillium Link, Rhizopus Ehrenb., Scopulariopsis Bainier.Conclusion. At the present stage of research, the success of seed storage at low and ultralow temperatures was demonstrated. We recommend cryopreservation for the long-term storage of improved and valuable seeds

New advances in Raman study of polyvinylchloride structure

In this work we investigated Raman spectra of a number of industrial grades of polyvinylchloride powder and films, prepared from solutions in tetrahydrofuran and acetophenone. The number and spectral characteristics of the Raman lines in the spectral regions of the C-Cl stretching vibrations and in the region of the C-H and CH2 stretching vibrations were evaluated