Applications of symbolic computing methods to the dynamic analysis of large systems

Since the symbolic computing language is very well suited to the operations with algebraic equations, techniques use the transfer function concept as a tool for the analysis of large linear dynamic systems. Techniques were coded in the experimental symbolic computer language FORMAC. The first of these approaches, REDUCE 1, establishes the techniques and a computer program to symbolically reduce arbitrary block diagrams associated with large systems for desired transfer functions. Symbolic closed form solutions are determined in several forms including an expanded form in terms of the driving frequencies and system constants. Programs are also written to numerically evaluate the symbolic solutions. A second computer program, REDUCE 2, is also based on the use of symbolic computing methods and was written to accommodate large engineering systems

Magnetic Resonance

Contains research objectives and reports on three research projects

Учет и контроль расчетов с дебиторами и кредиторами в ООО «Вектор»

Рассмотрены теоретические аспекты учета и контроля расчетов с дебиторами и кредиторами организации, основные определения, цели, задачи. Представлена краткая характеристика о предприятии ООО "Вектор", его видах деятельности, организационной структуре. Представлен подробный анализ предприятия ООО "Вектор" выявлены все слабые и сильные стороны. Представлены результаты проведенного исследования, а именно: предложения по совершенствованию учета и контроля расчетов с дебиторами и кредиторами.The theoretical aspects of accounting and control of settlements with debtors and creditors of the organization, the main definitions, goals, objectives are presented. A brief description of the enterprise “Vector”, its types of activities, organizational structure is presented. A detailed analysis of the enterprise “Vector” is presented. All weak and strong parties. The results of the study are presented, namely: proposals for improving the accounting and control of settlements with debtors and creditors

Carbon stable isotope analysis of cereal remains as a way to reconstruct water availability: preliminary results

Reconstructing past water availability, both as rainfall and irrigation, is important to answer questions about the way society reacts to climate and its changes and the role of irrigation in the development of social complexity. Carbon stable isotope analysis of archaeobotanical remains is a potentially valuable method for reconstructing water availability. To further define the relationship between water availability and plant carbon isotope composition and to set up baseline values for the Southern Levant, grains of experimentally grown barley and sorghum were studied. The cereal crops were grown at three stations under five different irrigation regimes in Jordan. Results indicate that a positive but weak relationship exists between irrigation regime and total water input of barley grains, but no relationship was found for sorghum. The relationship for barley is site-specific and inter-annual variation was present at Deir ‘Alla, but not at Ramtha and Khirbet as-Samra

Investigating the topology of interacting networks - Theory and application to coupled climate subnetworks

Network theory provides various tools for investigating the structural or functional topology of many complex systems found in nature, technology and society. Nevertheless, it has recently been realised that a considerable number of systems of interest should be treated, more appropriately, as interacting networks or networks of networks. Here we introduce a novel graph-theoretical framework for studying the interaction structure between subnetworks embedded within a complex network of networks. This framework allows us to quantify the structural role of single vertices or whole subnetworks with respect to the interaction of a pair of subnetworks on local, mesoscopic and global topological scales. Climate networks have recently been shown to be a powerful tool for the analysis of climatological data. Applying the general framework for studying interacting networks, we introduce coupled climate subnetworks to represent and investigate the topology of statistical relationships between the fields of distinct climatological variables. Using coupled climate subnetworks to investigate the terrestrial atmosphere's three-dimensional geopotential height field uncovers known as well as interesting novel features of the atmosphere's vertical stratification and general circulation. Specifically, the new measure "cross-betweenness" identifies regions which are particularly important for mediating vertical wind field interactions. The promising results obtained by following the coupled climate subnetwork approach present a first step towards an improved understanding of the Earth system and its complex interacting components from a network perspective

Diversity of a cytokinin dehydrogenase gene in wild and cultivated barley

The cytokinin dehydrogenase gene HvCKX2.1 is the regulatory target for the most abundant heterochromatic small RNAs in drought-stressed barley caryopses. We investigated the diversity of HvCKX2.1 in 228 barley landraces and 216 wild accessions and identified 14 haplotypes, five of these with ten or more members, coding for four different protein variants. The third largest haplotype was abundant in wild accessions (51 members), but absent from the landrace collection. Protein structure predictions indicated that the amino acid substitution specific to haplotype 3 could result in a change in the functional properties of the HvCKX2.1 protein. Haplotypes 1–3 have overlapping geographical distributions in the wild population, but the average rainfall amounts at the collection sites for haplotype 3 plants are significantly higher during November to February compared to the equivalent data for plants of haplotypes 1 and 2. We argue that the likelihood that haplotype 3 plants were excluded from landraces by sampling bias that occurred when the first wild barley plants were taken into cultivation is low, and that it is reasonable to suggest that plants with haplotype 3 are absent from the crop because these plants were less suited to the artificial conditions associated with cultivation. Although the cytokinin signalling pathway influences many aspects of plant development, the identified role of HvCKX2.1 in the drought response raises the possibility that the particular aspect of cultivation that mitigated against haplotype 3 relates in some way to water utilization. Our results therefore highlight the possibility that water utilization properties should be looked on as a possible component of the suite of physiological adaptations accompanying the domestication and subsequent evolution of cultivated barley

A comparison of Power Doppler with conventional sonographic imaging for the evaluation of renal artery stenosis

BACKGROUND: Power Doppler (PD) has improved diagnostic capabilities of vascular sonography, mainly because it is independent from the angle of insonation. We evaluated this technique in a prospective comparison with conventional imaging, consisting in Duplex and Color Doppler, for the evaluation of Renal Artery (RA) stenosis. METHODS: Sensitivity, specificity and predictive values of PD and conventional imaging were assessed in a blinded fashion on eighteen patients, 9 with angiographic evidence of unilateral RA stenosis (hypertensive patients) and 9 with angiographically normal arteries (control group). PD images were interpreted with an angiography-like criteria. RESULTS: In the control group both techniques allowed correct visualization of 16 out of the 18 normal arteries (93% specificity). Only in five hypertensive patients RA stenosis was correctly identified with conventional technique (56% sensitivity and 86% negative predictive value); PD was successful in all hypertensive patients (100% sensitivity and negative predictive value), since the operators could obtain in each case of RA stenosis a sharp color signal of the whole vessel with a clear "minus" at the point of narrowing of the lumen. All results were statistically significant (p < 0.01). CONCLUSIONS: This study demonstrates that PD is superior to conventional imaging, in terms of sensitivity and specificity, for the diagnosis of RA stenosis, because it allows a clear visualization of the whole stenotic vascular lumen. Especially if it is used in concert with the other sonographic techniques, PD can enable a more accurate imaging of renovascular disease with results that seem comparable to selective angiography