7,040 research outputs found
Worldsheet Geometries of Ambitwistor String
Mason and Skinner proposed the ambitwistor string theory which directly
reproduces the formulas for the amplitudes of massless particles proposed by
Cachazo, He and Yuan. In this paper we discuss geometries of the moduli space
of worldsheets associated to the bosonic or the RNS ambitwistor string.
Further, we investigate the factorization properties of the amplitudes when an
internal momentum is near on-shell in the abstract CFT language. Along the way,
we propose the existence of the ambitwistor strings with three or four
fermionic worldsheet currents.Comment: 31 pages, publised versio
Base composition of DNA in adenovirus-12-induced tumor
A series of experiments was conducted to study the base composition of DNA in AVl2-induced tumor and host cells by paper chromatography, and it was found that DNA per cent. guanine-cystosine contents were around 42 % in both of them. The base composition of DNA of AV12 itself differs considerably from that of AVl2-induced tumor cells, while
the DNA of tumor cells shows the property similar to that of host cell DNA. The genetical relationship among virus, host cells and tumor cells was discussed.</p
Open superstring field theory based on the supermoduli space
We present a new approach to formulating open superstring field theory based
on the covering of the supermoduli space of super-Riemann surfaces and
explicitly construct a gauge-invariant action in the Neveu-Schwarz sector up to
quartic interactions. The cubic interaction takes a form of an integral over an
odd modulus of disks with three punctures and the associated ghost is inserted.
The quartic interaction takes a form of an integral over one even modulus and
two odd moduli, and it can be interpreted as the integral over the region of
the supermoduli space of disks with four punctures which is not covered by
Feynman diagrams with two cubic vertices and one propagator. As our approach is
based on the covering of the supermoduli space, the resulting theory naturally
realizes an structure, and the two-string product and the
three-string product used in defining the cubic and quartic interactions are
constructed to satisfy the relations to this order.Comment: 60 pages, 3 figures; v2: minor corrections and references added; v3:
a proof that the quartic vertex is unambiguously defined for general
off-shell states added in appendix A.5, version published in JHE
Microbial ecosystem constructed in water for successful organic hydroponics
Conventional hydroponics systems generally use only chemical fertilisers, not organic ones, since there are no microbial ecosystems present in such systems to mineralise organic compounds to inorganic nutrients. Addition of organic compounds to the hydroponic solution generally has phytotoxic effects and causes poor plant growth. We developed a novel hydroponic culture method using organic fertiliser. A microbial ecosystem was constructed in hydroponic solution by regulating the amounts of organic fertiliser and soil, with moderate aeration. The microbial ecosystem mineralised organic nitrogen to nitrate-nitrogen via ammonification and nitrification. A 97.6% efficiency of nitrate-nitrogen generation from the organic nitrogen in the organic fertiliser was achieved. The culture solution containing the microbial ecosystem was usable as a hydroponic solution. Vegetable plants grew well in our organic hydroponics system under continuous addition of organic fertiliser, and the yield and quality approximated those of vegetables grown by conventional hydroponics
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