Resonant structure of space-time of early universe

A new fully quantum method describing penetration of packet from internal well outside with its tunneling through the barrier of arbitrary shape used in problems of quantum cosmology, is presented. The method allows to determine amplitudes of wave function, penetrability $T_{\rm bar}$ and reflection $R_{\rm bar}$ relatively the barrier (accuracy of the method: $|T_{\rm bar}+R_{\rm bar}-1| < 1 \cdot 10^{-15}$), coefficient of penetration (i.e. probability of the packet to penetrate from the internal well outside with its tunneling), coefficient of oscillations (describing oscillating behavior of the packet inside the internal well). Using the method, evolution of universe in the closed Friedmann--Robertson--Walker model with quantization in presence of positive cosmological constant, radiation and component of generalize Chaplygin gas is studied. It is established (for the first time): (1) oscillating dependence of the penetrability on localization of start of the packet; (2) presence of resonant values of energy of radiation $E_{\rm rad}$, at which the coefficient of penetration increases strongly. From analysis of these results it follows: (1) necessity to introduce initial condition into both non-stationary, and stationary quantum models; (2) presence of some definite values for the scale factor $a$, where start of expansion of universe is the most probable; (3) during expansion of universe in the initial stage its radius is changed not continuously, but passes consequently through definite discrete values and tends to continuous spectrum in latter time.Comment: 18 pages, 14 figures, 4 table

Measurement of pH. Definition, standards, and procedures (IUPAC Recommendations 2002)

The definition of a "primary method of measurement" [1] has permitted a full consideration of the definition of primary standards for pH, determined by a primary method (cell without transference, Harned cell), of the definition of secondary standards by secondary methods, and of the question whether pH, as a conventional quantity, can be incorporated within the internationally accepted system of measurement, the International System of Units (SI, Syst\ue8me International d'Unit\ue9s). This approach has enabled resolution of the previous compromise IUPAC 1985 Recommendations [2]. Furthermore, incorporation of the uncertainties for the primary method, and for all subsequent measurements, permits the uncertainties for all procedures to be linked to the primary standards by an unbroken chain of comparisons. Thus, a rational choice can be made by the analyst of the appropriate procedure to achieve the target uncertainty of sample pH. Accordingly, this document explains IUPAC recommended definitions, procedures, and terminology relating to pH measurements in dilute aqueous solutions in the temperature range 5-50 \ub0C. Details are given of the primary and secondary methods for measuring pH and the rationale for the assignment of pH values with appropriate uncertainties to selected primary and secondary substances

S1-sensitive sites in the supercoiled double-stranded form of tomato golden mosaic virus DNA component B : Identification of regions of potential alternative secondary structure and regulatory function

The sensitivity of the supercoiled double-stranded form of the DNA of tanato golden mosaic virus (TGMV), a geminivirus, to the single-strand specific enzyme S1 nuclease has been demonstrated. Specific S1 cleavage sites were identified in TGMV DNA component B by cloning into the single-strand bacteriophage vector M13 mp8 and sequencing of the inserted DNA. Analysis of the DNA sequence at the sites of S1 sensitivity in TGMV DNA component B revealed several possible regions of alternative secondary structure which were clustered in an intergenic region upstream of the starts of the two major open reading frames which are in opposite orientations. This region contains putative transcriptional promoter and modulatory sequences and a possible replication origin. The extreme S1 sensitivity of the supercoiled form of TGMV DNA component A precluded its cloning under the conditions employed for selective cleavage of DNA component B.Peer reviewe

Characterisation of multimeric DNA forms associated with tomato golden mosaic virus infection

Homodimeric and trimeric double-stranded DNA forms of both components of the genome of the geminivirus, tomato golden mosaic virus have been isolated from infected Nicotiana tabacum plants and characterised.Peer reviewe

The behaviour of tomato golden mosaic virus DNA in cultured cells isolated from systemically infected tobacco leaves

When callus tissue was cultured from leaf pieces taken from a Nicotiana tabacum cv. Xanthi nc. plant systemically infected with tomato golden mosaic virus (TGMV), TGMV-specific DNA persisted for up to 6 months in culture. Analysis of TGMV-specific intracellular DNA forms indicated a decrease in double-stranded relative to single-stranded forms and an increase in sub-genomic relative to genomic single-stranded DNA species in the callus tissue compared to those in the original leaf explant. The implications of the results with regard to TGMV replication are discussedPeer reviewe

Negatively supercoiled DNA from plants infected with a single-stranded DNA virus

A method for isolating covalently closed circular double-stranded DNA from plants infected with the geminivirus, tomato golden mosaic virus, is described. Ethidium bromide titration showed this DNA to be negatively supercoiled with a superhelical density of - 0.062. The presence of S1 nuclease-sensitive secondary structure in the supercoiled DNA was demonstrated by its conversion to the open circular and linear DNA forms on treatment with this enzymePeer reviewe

Gene amplification and expression in plants by a replicating geminivirus vector

The use of plant DNA viruses as vectors for the transfer of foreign genes to plants offers two potential advantages over other, existing methods of producing transgenic plants. First, these viruses sys-temically infect whole plants, thus obviating the need for the difficult and time-consuming step of regeneration from transformed single cells or protoplasts. Second, the viruses replicate as separate, autonomous entities within the plant's cells so that any gene cloned in a plant DNA-virus vector would be amplified to high copy number, a feature that differs from methods that produce transgenic plants by the chromosomal integration of foreign DNA. To date, attention has focused on the development of vectors based on the cauliflower mosaic virus (CaMV), but their use is hampered by the narrow range of plants infected by CaMV, and by practical limitations on inserting foreign DNA that are imposed by the biology of CaMV. Here we describe the use of vectors based on the gemini tomato golden mosaic virus (TGMV) to introduce the neomycin phosphotransferase (neo gene) into plants. Our results indicate that geminivirus-derived vectors should be useful not only for amplification of gene expression by the systemic infection of plants, but also for heritable gene amplification by the integration of stable master copies of the vector into the plant chromosomal DNA.Peer reviewe