23 research outputs found

    Limits on the Non-Standard Interactions of Neutrinos from e+e−e^+ e^- Colliders

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    We provide an effective Lagrangian analysis of contact non-standard interactions of neutrinos with electrons, which can be effectively mediated by extra particles, and examine the associated experimental limits. At present, such interactions are strongly constrained only for ΜΌ\nu_\mu: the bounds are loose for Îœe\nu_e and absent for Μτ\nu_\tau. We emphasize the unique role played by the reaction e+eâˆ’â†’ÎœÎœË‰Îłe^+e^-\to \nu \bar{\nu}\gamma in providing direct constraints on such non-standard interactions.Comment: 15 LaTeX pages, 6 postscript figures, uses epsfig. New discussion on bounds from reactor anti-neutrino scattering off electrons; minor changes. To appear on Phys. Lett.

    An Approach to the Cosmological Constant Problem(s)

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    We propose an approach to explaining why naive large quantum fluctuations are not the right estimate for the cosmological constant. We argue that the universe is in a superposition of many vacua, in such a way that the resulting fluctuations are suppressed by level repulsion to a very small value. The approach combines several aspects of string theory and the early history of the universe, and is only valid if several assumptions hold true. The approach may also explain why the effective cosmological constant reamins small as the universe evolves though several phase transitions. It provides a non-anthropic mechansim leading to a small, non-zero cosmological constant.Comment: Talk given at Rencontres de Moriond, 2004 by G.L. Kan

    CRISPR/Cas9-induced modification of the conservative promoter region of VRN-A1 alters the heading time of hexaploid bread wheat

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    In cereals, the vernalization-related gene network plays an important role in regulating the transition from the vegetative to the reproductive phase to ensure optimal reproduction in a temperate climate. In hexaploid bread wheat (Triticum aestivum L.), the spring growth habit is associated with the presence of at least one dominant locus of VERNALIZATION 1 gene (VRN-1), which usually differs from recessive alleles due to mutations in the regulatory sequences of the promoter or/and the first intron. VRN-1 gene is a key regulator of floral initiation; various combinations of dominant and recessive alleles, especially VRN-A1 homeologs, determine the differences in the timing of wheat heading/flowering. In the present study, we attempt to expand the types of VRN-A1 alleles using CRISPR/Cas9 targeted modification of the promoter sequence. Several mono- and biallelic changes were achieved within the 125-117 bp upstream sequence of the start codon of the recessive vrn-A1 gene in plants of semi-winter cv. ‘Chinese Spring’. New mutations stably inherited in subsequent progenies and transgene-free homozygous plants carrying novel VRN-A1 variants were generated. Minor changes in the promoter sequence, such as 1–4 nucleotide insertions/deletions, had no effect on the heading time of plants, whereas the CRISPR/Cas9-mediated 8 bp deletion between −125 and −117 bp of the vrn-A1 promoter shortened the time of head emergence by up to 2-3 days. Such a growth habit was consistently observed in homozygous mutant plants under nonvernalized cultivation using different long day regimes (16, 18, or 22 h), whereas the cold treatment (from two weeks and more) completely leveled the effect of the 8 bp deletion. Importantly, comparison with wild-type plants showed that the implemented alteration has no negative effects on main yield characteristics. Our results demonstrate the potential to manipulate the heading time of wheat through targeted editing of the VRN-A1 gene promoter sequence on an otherwise unchanged genetic background

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    The Effect of Daminozide, Dark/Light Schedule and Copper Sulphate in Tissue Culture of Triticum timopheevii

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    Triticum timopheevii Zhuk. is a tetraploid wheat that is utilized worldwide as a valuable breeding source for wheat improvement. Gene-based biotechnologies can contribute to this field; however, T. timopheevii exhibits recalcitrance and albinism in tissue cultures, making this species of little use for manipulation through genetic engineering and genome editing. This study tested various approaches to increasing in vitro somatic embryogenesis and plant regeneration, while reducing the portion of albinos in cultures derived from immature embryos (IEs) of T. timopheevii. They included (i) adjusting the balance between 2,4-D and daminozide in callus induction medium; (ii) cultivation using various darkness/illumination schedules; and (iii) inclusion of additional concentrations of copper ions in the tissue culture medium. We achieved a 2.5-fold increase in somatic embryogenesis (up to 80%) when 50 mg L−1 daminozide was included in the callus induction medium together with 3 mg L−1 2,4-D. It was found that the dark cultivation for 20–30 days was superior in terms of achieving maximum culture efficiency; moreover, switching to light in under 2 weeks from culture initiation significantly increased the number of albino plants, suppressed somatic embryogenesis, and decreased the regeneration of green plants. Media containing higher levels of copper ions did not have a positive effect on the regeneration of green plants; contrarily, the elevated concentrations caused albinism in plantlets. The results and relevant conclusions of the present study might be valuable for establishing an improved protocol for the regeneration of green plants in tissue cultures of T. timopheevii

    Application of automated systems for quality control of ground anti-icing treatment of aircraft

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    For the first time, this paper addresses the need to automate the maintenance of the quality control and control system at all stages and stages of the life cycle - anti-conduct fluid (POJ) for ground-based anti-de-dealing treatment (POO) of an aircraft. The possibility of evolution of the quality control of the object of ground de-icing physical and chemical treatment of the surface of the aircraft - de-icing liquids, in “Management of quality - de-icing liquid as an object to ensure the safe take-off of the aircraft” is considered. The definition was introduced: “The quality of de-icing liquid.” To integrate into the system “Management of the quality of de-icing fluid” - on the basis of knowledge bases about THE POJ introduced as a functional concept “The quality of de-icing liquid at the POO stage”. In order to introduce information software support for the POO process using databases and control systems, the concept of “Regeloscopic Ground De-Icing Protection Program of the Armed Forces” has been introduced, which will allow and move to an effective method of improving the quality of the service - integrated automation of the POO

    DataSheet_1_CRISPR/Cas9-induced modification of the conservative promoter region of VRN-A1 alters the heading time of hexaploid bread wheat.pdf

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    In cereals, the vernalization-related gene network plays an important role in regulating the transition from the vegetative to the reproductive phase to ensure optimal reproduction in a temperate climate. In hexaploid bread wheat (Triticum aestivum L.), the spring growth habit is associated with the presence of at least one dominant locus of VERNALIZATION 1 gene (VRN-1), which usually differs from recessive alleles due to mutations in the regulatory sequences of the promoter or/and the first intron. VRN-1 gene is a key regulator of floral initiation; various combinations of dominant and recessive alleles, especially VRN-A1 homeologs, determine the differences in the timing of wheat heading/flowering. In the present study, we attempt to expand the types of VRN-A1 alleles using CRISPR/Cas9 targeted modification of the promoter sequence. Several mono- and biallelic changes were achieved within the 125-117 bp upstream sequence of the start codon of the recessive vrn-A1 gene in plants of semi-winter cv. ‘Chinese Spring’. New mutations stably inherited in subsequent progenies and transgene-free homozygous plants carrying novel VRN-A1 variants were generated. Minor changes in the promoter sequence, such as 1–4 nucleotide insertions/deletions, had no effect on the heading time of plants, whereas the CRISPR/Cas9-mediated 8 bp deletion between −125 and −117 bp of the vrn-A1 promoter shortened the time of head emergence by up to 2-3 days. Such a growth habit was consistently observed in homozygous mutant plants under nonvernalized cultivation using different long day regimes (16, 18, or 22 h), whereas the cold treatment (from two weeks and more) completely leveled the effect of the 8 bp deletion. Importantly, comparison with wild-type plants showed that the implemented alteration has no negative effects on main yield characteristics. Our results demonstrate the potential to manipulate the heading time of wheat through targeted editing of the VRN-A1 gene promoter sequence on an otherwise unchanged genetic background.</p
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