2,221 research outputs found
On the structure of the seminal receptacle in cyclopids (Copepoda, Cyclopoida). [Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod (6) 26-31, 1970.]
The seminal bag, or seminal receptacle, forms a characteristic organ of cyclopids, serving for retention of the sperms discharged from the spermatophores. The structure of the seminal receptacle, more precisely its form, is fairly widely used in diagnosis and undoubtedly can be more widely applied in the systematics of the group. Within the limits of the family Cyclopidae it is possible to distinguish crustaceans with three basic types of seminal bag. The differences consist of the position which this organ occupies in the genital segment. of one species, we carried out a series of observations on its formation in ontogenesis and during the life of the adult stage. As material for observation the study used laboratory cultures of three species; Acanthocyclops americanus (Marsh) from the plankton of the Moscow River, Cyclops vicinus Uljan and Mesocyclops leuckarti Glaus from the plankton of the channel section of the upper part of the Gorkovsk reservoir. The author concluded that the irreversibility of the changes in the seminal receptacle presents the possibility of utilising this structure as one of the indicators of the growth of the individual
Most Efficient Homogeneous Volatility Estimators
We present a comprehensive theory of homogeneous volatility (and variance)
estimators of arbitrary stochastic processes that fully exploit the OHLC (open,
high, low, close) prices. For this, we develop the theory of most efficient
point-wise homogeneous OHLC volatility estimators, valid for any price
processes. We introduce the "quasi-unbiased estimators", that can address any
type of desirable constraints. The main tool of our theory is the parsimonious
encoding of all the information contained in the OHLC prices for a given time
interval in the form of the joint distributions of the high-minus-open,
low-minus-open and close-minus-open values, whose analytical expression is
derived exactly for Wiener processes with drift. The distributions can be
calculated to yield the most efficient estimators associated with any
statistical properties of the underlying log-price stochastic process. Applied
to Wiener processes for log-prices with drift, we provide explicit analytical
expressions for the most efficient point-wise volatility and variance
estimators, based on the analytical expression of the joint distribution of the
high-minus-open, low-minus-open and close-minus-open values. The efficiency of
the new proposed estimators is favorably compared with that of the
Garman-Klass, Roger-Satchell and maximum likelihood estimators.Comment: 46 pages including 17 figure
Adatom incorporation and step crossing at the edges of 2D nanoislands
Adatom incorporation into the ``faceted'' steps bordering the 2D nanoislands
is analyzed. The step permeability and incorporation coefficients are derived
for some typical growth situations. It is shown that the step consisting of
equivalent straight segments can be permeable even in the case of fast egde
migration if there exist factors delaying creation of new kinks. The step
consisting of alternating rough and straight segments may be permeable if there
is no adatom transport between neighboring segments through the corner
diffusion.Comment: 3 pages, one figur
Model-oriented co-design of homogeneous computing systems
This article proposes an approach to the construction of a technological platform for designing function-oriented processors (FOP) built on the basis of homogeneous computing environments (OVS). A feature of the proposed approach is the use of co-design - a simultaneous and interconnected design of hardware (HW) and software (SW) FOP components. The paper presents proposals for the implementation of this approach, based on the use of the prin-ciple of model-based design, which allows you to make the co-design process iterative and effectively distribute data processing procedures between HW and SW - components of FOP. Based on the consideration of the experience in implementing such solutions, the paper presents the composition of functional subsystems of technological platforms, a diagram of information interaction between these subsystems based on intensive using of web-technologies at all stages of the design and operation of FOP. © 2019 Tomsk State University. All rights reserved
Simulation of permafrost changes due to technogenic influences of different ingeneering constructions used in nothern oil and gas fields
Significant amount of oil and gas is producted in Russian Federation on the territories with permafrost soils. Ice-saturated rocks thawing due to global warming or effects of various human activity will be accompanied by termocarst and others dangerous geological processes in permafrost. Design and construction of well pads in permafrost zones have some special features. The main objective is to minimize the influence of different heat sources (engineering objects) inserted into permafrost and accounting long-term forecast of development of permafrost degradation due to different factors in particular generated by human activity. In this work on the basis a mathematical model and numerical algorithms approved on 11 northern oil and gas fields some effects obtained by carrying out numerical simulations for various engineering systems are discussed. © Published under licence by IOP Publishing Ltd.This work was supported by RFBR projects (16-01-00401, 14-01-00155) by contract 02.A03.21.0006 (reg.N211 of RF Government) and Program of UB RAS, project 15-7-1-13
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