729 research outputs found
Novel steady state of a microtubule assembly in a confined geometry
We study the steady state of an assembly of microtubules in a confined
volume, analogous to the situation inside a cell where the cell boundary forms
a natural barrier to growth. We show that the dynamical equations for growing
and shrinking microtubules predict the existence of two steady states, with
either exponentially decaying or exponentially increasing distribution of
microtubule lengths. We identify the regimes in parameter space corresponding
to these steady states. In the latter case, the apparent catastrophe frequency
near the boundary was found to be significantly larger than that in the
interior. Both the exponential distribution of lengths and the increase in the
catastrophe frequency near the cell margin is in excellent agreement with
recent experimental observations.Comment: 8 pages, submitted to Phys. Rev.
Environment quality management in green cities
The article is devoted to the issues of improvement of quality of urban environment during realization of the project of development of green cities, which combines economic and ecological advantages. The article substantiates top-priority directions of change of approaches to management of urban territories and integration of efforts of science, business, and society in promotion of green technologies. The main methodological approach to provision of ecological balance in green cities consists in development of the most comprehensive complex of ecological and economic indicators of development of the city in view of implementation of progressive technologies of filtration of industrial emissions into the atmosphere, sewage water treatment, waste processing, etc. The article offers methodological substantiation of the system of indicators which include evaluation of anthropogenic influence on urban environment and calculation of integrated economic effect from implementation of green technologies which minimize unfavorable effect of these influences. These indicators include emissions release into the atmosphere, soil pollution, development of green areas, use of urban territories which are taken out from the system of natural use, use of city public transport, etc. The developed indicators can not only reflect the existing ecological state and economic development of the city fully but be used for development of perspective scenarios of development of green urban economy on the basis of industrially developed middle-sized cities of Russia and the CIS.peer-reviewe
Concept - strategy “green cities” on the basis of medium industrially developed cities of Russia and CIS countries
The work is oriented at conceptual and methodological substantiation of the strategy of formation of “green cities” on the basis of medium industrially developed cities of Russia and post-Soviet countries, which provide new ecological and socio-economic standards of living standards of population. The concept of “green city” has not only to correspond to imperatives of competitiveness, sustainability, and security of economy, but to form mechanisms of creation of material and informational, humanitarian and technical, institutional and organizational, commercial and financial conditions for effective realization of potential of medium cities. In order to substantiate the results of the research, the following methods of scientific analysis were used: systemic, situational, historical and logical, typological; methods of structural & functional, subjective & objective, descriptive, comparative, expert, statistical, graphic, and table analysis, and economic & mathematical modeling. Study of the processes of transformation of socio-economic system of medium cities on the basis of developed institutional criteria allowed expanding methodological basis of strategic management – in particular, substantiating the totality of methodological and methodical decisions, related to conduct of the analysis, substantiation of goals and mission, development and realization of strategy. Analysis of external and internal possibilities and limitations of medium city development allows determining factors which influence its state and trajectory of development positively and negatively: organizational & managerial (dominant of local authorities’ focus at cooperation with regional and federal structures), technical and technological (orientation of vector of industry modernization), infrastructural (imperative of implementation of resource-saving technologies), ecological (recession of ecological culture of population), tourist and recreational (slowdown in development of recreational resources and creation of tourism industry), informational and communicational (priority of creation of “E-city”), and social (horizon of new social standards).peer-reviewe
Management of socio-economic components of branding in the company
The article is devoted to defining of an essence of brand as the single whole integrity of socioeconomic promises to a consumer. In this connection the analysis of notion 'branding' is made. The authors give their own interpretation of branding as strategic process. The relationship between brand and consumer is revealed which is built in inter-influence from both sides. It is emphasized that the more stronger this relationship is the more stronger the brand will be. © IDOSI Publications, 2013
Research of academic motivation at the stage of forming a threshold level of mastering competences
The relevance of researched problem is caused by the society requirement to form and implement educational and creative potential of a student as a conductor of changes that set a high level of motivational behavior. The aim of this article is to develop a structural model of motivational behavior of students that allow carrying out modeling of specific characteristics and their practical application. The leading approach to the research of this problem is the provision of the theory of self-determination on basic needs that allow considering basics of intrinsic motivation. The results of the research are: the structural model of motivational behavior is considered in the article, the questions are selected and the questionnaire on educational motivation is developed for the poll of student's groups “Economy and Management”. The development and approbation of multi-profile software programs are “Students’ Questionnaire” to implement on-line poll or interviews with students on academic motivation. The results of the research can be useful for specialized structural divisions of the university, teachers, and also for the students in case of further research of the issues of academic motivation and individual educational paths. © 2016 Eremicheva et al
Problems and prospects of development of ecological tourism in Ireland
The paper presents the research on the development of ecological tourism in Ireland. The basic directions and problems of development of ecotourism. Income from ecotourism in the country was analyzed in the article, as well as the model for the attraction of tourists to Irelan
Isolation and functional characterization of a high affinity urea transporter from roots of Zea mays
Background
Despite its extensive use as a nitrogen fertilizer, the role of urea as a directly accessible nitrogen source for crop plants is still poorly understood. So far, the physiological and molecular aspects of urea acquisition have been investigated only in few plant species highlighting the importance of a high-affinity transport system. With respect to maize, a worldwide-cultivated crop requiring high amounts of nitrogen fertilizer, the mechanisms involved in the transport of urea have not yet been identified. The aim of the present work was to characterize the high-affinity urea transport system in maize roots and to identify the high affinity urea transporter.
Results
Kinetic characterization of urea uptake (<300 \u3bcM) demonstrated the presence in maize roots of a high-affinity and saturable transport system; this system is inducible by urea itself showing higher Vmax and Km upon induction. At molecular level, the ORF sequence coding for the urea transporter, ZmDUR3, was isolated and functionally characterized using different heterologous systems: a dur3 yeast mutant strain, tobacco protoplasts and a dur3 Arabidopsis mutant. The expression of the isolated sequence, ZmDUR3-ORF, in dur3 yeast mutant demonstrated the ability of the encoded protein to mediate urea uptake into cells. The subcellular targeting of DUR3/GFP fusion proteins in tobacco protoplasts gave results comparable to the localization of the orthologous transporters of Arabidopsis and rice, suggesting a partial localization at the plasma membrane. Moreover, the overexpression of ZmDUR3 in the atdur3-3 Arabidopsis mutant showed to complement the phenotype, since different ZmDUR3-overexpressing lines showed either comparable or enhanced 15[N]-urea influx than wild-type plants. These data provide a clear evidence in planta for a role of ZmDUR3 in urea acquisition from an extra-radical solution.
Conclusions
This work highlights the capability of maize plants to take up urea via an inducible and high-affinity transport system. ZmDUR3 is a high-affinity urea transporter mediating the uptake of this molecule into roots. Data may provide a key to better understand the mechanisms involved in urea acquisition and contribute to deepen the knowledge on the overall nitrogen-use efficiency in crop plants
STANDARDIZATION OF METHODS OF CORROSION PROTECTION IN THE OIL REFINING COMPLEX
Nowadays, many industries suffer losses from the failure of technical products due to damage to products and materials resulting from corrosion. The cause of corrosion is not only exposure to the external environment, but it can also be early aging of the metal, bio-damage. As a result, modern equipment manufacturers are finding more and more technologically effective ways to combat corrosion. All methods of protection used must be regulated. Therefore, one of the most effective ways to solve the problems of protecting metals from corrosion is their comprehensive standardization. This paper will consider a set of standards used in the manufacture of equipment to protect it from corrosion and aging.В настоящее время многие предприятия несут потери из-за выхода из строя оборудования, возникающего в результате коррозии. Причиной коррозии является не только воздействие внешней среды, но и раннее старение металла, биоповреждения. Вследствие чего современные производители оборудования находят все более технологически эффективные способы борьбы с коррозией. Все используемые способы защиты должны быть регламентированы и нормированы. Поэтому, одним из эффективных путей решения вопросов защиты металлов от коррозии, является их комплексная стандартизация. В данной работе будет рассмотрен комплекс стандартов, применяемых в производстве оборудования для защиты его от коррозии и старения
Subaru optical observations of the old pulsar PSR B0950+08
We report the B band optical observations of an old (17.5 Myr) radiopulsar
PSR B0950+08 obtained with the Suprime-Cam at the Subaru telescope. We detected
a faint object, B=27.07(16). Within our astrometrical accuracy it coincides
with the radio position of the pulsar and with the object detected earlier by
Pavlov et al. (1996) in UV with the HST/FOC/F130LP. The positional coincidence
and spectral properties of the object suggest that it is the optical
counterpart of PSR B0950+08. Its flux in the B band is two times higher than
one would expect from the suggested earlier Rayleigh-Jeans interpretation of
the only available HST observations in the adjacent F130LP band. Based on the B
and F130LP photometry of the suggested counterpart and on the available X-ray
data we argue in favour of nonthermal origin of the broad-band optical spectrum
of PSR B0950+08, as it is observed for the optical emission of the younger,
middle-aged pulsars PSR B0656+14 and Geminga. At the same time, the optical
efficiency of PSR B0950+08, estimated from its spin-down power and the detected
optical flux, is by several orders of magnitude higher than for these pulsars,
and comparable with that for the much younger and more energetic Crab pulsar.
We cannot exclude the presence of a compact, about 1'', faint pulsar nebula
around PSR B0950+08, elongated perpendicular to the vector of its proper
motion, unless it is not a projection of a faint extended object on the pulsar
position.Comment: 8 pages, LaTeX, aa.cls style, 5 PS figures, submitted to A&A. Image
is available in FITS format at
http://www.ioffe.rssi.ru/astro/NSG/obs/0950-subar
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