436 research outputs found
Artificial Induction of Polyploidy in Orchids by the Use of Colchicine
In the orchid industry, polyploidy has come to assume a prominent role in the production of superior types. Because polyploid orchids have been established to be generally superior to their diploid counterparts, the artificial induction of polyploidy assumes particular significance. If somatic doubling can be induced at will with a chemical such as colchicine, superior horticultural varieties might be obtained immediately. Such induced tetraploids might be utilized in breeding further polyploids. In the course of an extensive breeding program in orchids, a relatively high degree of sterility has been encountered among intergeneric hybrids and to a lesser degree among interspecific hybrids. Restoration of fertility among the sterile hybrids was found desirable in order to advance the breeding program. In accordance with these considerations, attempts were made to find practical methods for inducing polyploids in selected orchid groups by the use of colchicine. This investigation also entailed the study of the characteristics of the induced polyploids and comparing them with their diploid counterparts with respect to morphological differences
Anthurium Culture with Emphasis on the Effects of Some Induced Environments on Growth and Flowering
Efficiency in growth and flowering of the anthurium plant depends upon a number of factors, of which growing medium and sunlight level may be considered the two most important factors. This paper gives the results of testing bagasse as a medium for growing anthuriums, Also included in this paper are results from experiments showing the effects of various levels of sunlight intensity, a factor equally as important as the growing medium. In order to develop a broad understanding of the nature of the anthurium plant, especially with respect to the cultural aspects, several other factors which might affect growth and flowering were also investigated and the results are presented herein
Организационные резервы повышения производительности труда на предприятиях нефтегазовой отрасли
Проблема повышения производительности труда в современной экономике России имеет значительную актуальность, поскольку повышение уровня производительности труда является важнейшим условием социально-экономического развития общества, устойчивого экономического роста и повышения конкурентоспособности национальной экономики. Актуальность представленного исследования определяется необходимостью повышения производительности труда на современных предприятиях России, что может быть достигнуто за счет реализации организационных резервов роста. Целью исследования является структурирование факторов, оказывающих влияние на уровень производительности труда, подтверждение значимости организационных резервов роста, апробация методики выявления организационных резервов повышения производительности труда. Методы исследования. В настоящей работе нашли применение методы сбора первичной экономической информации, включая анализ законодательных и нормативно-правовых актов РФ, официальных статистических данных, данных публичной отчетности отечественных предприятий, анализ прочих открытых источников информации, системный подход, методы статистического и сравнительного анализа. The country's labor productivity in modern Russia over recent years has acquired impressive relevance. Since it is a key indicator of overall economic efficiency, strong labor productivity growth has always been a sufficient condition for socio-economic development, economic stability and enhancing competitiveness of the national economy. The relevance of the study is determined by the urgency of the labor productivity growth at the modern Russian factories that can be achieved through realization of organizational reserves. The main aim of the study is identifying and structuring the factors that seem to affect labor productivity level. It is also pointed at corroborating the necessity of labor productivity growth and approbation of organizational reserves seeking method. Methods. In the present work different methods of information gathering and processing were used to obtain the economic data including the analysis of appropriate laws and regulations, official statistics, companies' public statements and reporting and other open available resources. Also system approach, comparative and statistical analysis were adopted in this research
Extra gauge symmetries in BHT gravity
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive
gravity, linearized around a maximally symmetric background. At the critical
point in the space of parameters, defined by , we discover an
extra gauge symmetry, which reflects the existence of the partially massless
mode. The number of the Lagrangian degrees of freedom is found to be 1. We show
that the canonical structure of the theory at the critical point is unstable
under linearization.Comment: LATEX, 12 page
Quadratic Curvature Gravity with Second Order Trace and Massive Gravity Models in Three Dimensions
The quadratic curvature lagrangians having metric field equations with second
order trace are constructed relative to an orthonormal coframe. In
dimensions, pure quadratic curvature lagrangian having second order trace
constructed contains three free parameters in the most general case. The fourth
order field equations of some of these models, in arbitrary dimensions, are
cast in a particular form using the Schouten tensor. As a consequence, the
field equations for the New massive gravity theory are related to those of the
Topologically massive gravity. In particular, the conditions under which the
latter is "square root" of the former are presented.Comment: 24 pages, to appear in GR
Black-hole dynamics in BHT massive gravity
Using an exact Vaidya-type null-dust solution, we study the area and entropy
laws for dynamical black holes defined by a future outer trapping horizon in
(2+1)-dimensional Bergshoeff-Hohm-Townsend (BHT) massive gravity. We consider
the theory admitting a degenerate (anti-)de Sitter vacuum and pure BHT gravity.
It is shown that, while the area of a black hole decreases by the injection of
a null dust with positive energy density in several cases, the Wald-Kodama
dynamical entropy always increases.Comment: 7 pages, 1 figur
A Complete Classification of Higher Derivative Gravity in 3D and Criticality in 4D
We study the condition that the theory is unitary and stable in
three-dimensional gravity with most general quadratic curvature,
Lorentz-Chern-Simons and cosmological terms. We provide the complete
classification of the unitary theories around flat Minkowski and (anti-)de
Sitter spacetimes. The analysis is performed by examining the quadratic
fluctuations around these classical vacua. We also discuss how to understand
critical condition for four-dimensional theories at the Lagrangian level.Comment: 20 pages, v2: minor corrections, refs. added, v3: logic modified, v4:
typos correcte
The rejuvenating power of the Buena Vista Social Club
26S proteasome, a major regulatory protease in eukaryotes, consists of a 20S proteolytic core particle (CP) capped by a 19S regulatory particle (RP). The 19S RP is divisible into base and lid sub-complexes. Even within the lid, subunits have been demarcated into two modules: module 1 (Rpn5, Rpn6, Rpn8, Rpn9 and Rpn11), which interacts with both CP and base sub-complexes and module 2 (Rpn3, Rpn7, Rpn12 and Rpn15) that is attached mainly to module 1. We now show that suppression of RPN11 expression halted lid assembly yet enabled the base and 20S CP to pre-assemble and form a base-CP. A key role for Regulatory particle non-ATPase 11 (Rpn11) in bridging lid module 1 and module 2 subunits together is inferred from observing defective proteasomes in rpn11–m1, a mutant expressing a truncated form of Rpn11 and displaying mitochondrial phenotypes. An incomplete lid made up of five module 1 subunits attached to base-CP was identified in proteasomes isolated from this mutant. Re-introducing the C-terminal portion of Rpn11 enabled recruitment of missing module 2 subunits. In vitro, module 1 was reconstituted stepwise, initiated by Rpn11–Rpn8 heterodimerization. Upon recruitment of Rpn6, the module 1 intermediate was competent to lock into base-CP and reconstitute an incomplete 26S proteasome. Thus, base-CP can serve as a platform for gradual incorporation of lid, along a proteasome assembly pathway. Identification of proteasome intermediates and reconstitution of minimal functional units should clarify aspects of the inner workings of this machine and how multiple catalytic processes are synchronized within the 26S proteasome holoenzymes
Hamiltonian analysis of BHT massive gravity
We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT)
massive gravity with a cosmological constant. In the space of coupling
constants , our canonical analysis reveals the special role of
the condition . In this sector, the dimension of the
physical phase space is found to be , which corresponds to two
Lagrangian degree of freedom. When applied to the AdS asymptotic region, the
canonical approach yields the conserved charges of the BTZ black hole, and
central charges of the asymptotic symmetry algebra.Comment: LATEX, 21 pages; v2: minor correction
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