Common Structural Model Research Articles

Detailed secondary structure models of invertebrate 7SK RNAs

ABSTRACTThe 7SK RNA is a small nuclear RNA that is involved in the regulation of Pol-II transcription. It is very well conserved in vertebrates, but shows extensive variations in both sequence and structure across invertebrates. A systematic homology search extended the collection of 7SK genes in both Arthropods and Lophotrochozoa making use of the large number of recently published invertebrate genomes. The extended data set made it possible to infer complete consensus structures for invertebrate 7SK RNAs. These show that not only the well-conserved 5′- and 3′- domains but all the interior Stem A domain is universally conserved. In contrast, Stem B region exhibits substantial structural variation and does not adhere to a common structural model beyond phylum level.

Content-based unsupervised segmentation of recurrent TV programs using grammatical inference

TV program segmentation raised as a major topic in the last decade for the task of high quality indexing of multimedia content. Earlier studies of TV program segmentation are either highly supervised (e.g., event detection) or too specific to a certain type of program (e.g., cluster-based methods), which is not practically usable for indexing tasks because of the lack of generality of programs types. In this paper, we address the problem of unsupervised TV program segmentation by leveraging grammatical inference, i.e., discovering a common structural model shared by a collection of episodes of a recurrent TV program by finding an optimal alignment of structural elements across episodes. Structural elements referring to a video segment with a particular syntactic meaning with respect to the video structure. The use of symbolic representation of structural elements makes grammatical inference feasible to be applied on TV program modeling, and makes TV program segmentation possible to rely on only minimal domain knowledge. The proposed approach is operated in two phases. The first phase aims at obtaining a symbolic representation of each episode, where the elements relevant to the structure are discovered based on recurrence mining. The second phase is that of grammatical inference from the symbolic representation of episodes. We investigate two inference techniques, one based on multiple sequence alignment and one relying on uniform resampling, to infer structural grammars for TV programs. A model of the structure is derived from the structural grammars and used to predict the structure of new episodes. Comparative evaluation on two grammar inference approaches demonstrates that the models obtained can reflect the structure of the program and predict the structure of unseen episodes, which is the main application of the proposed approach in industry, i.e., to assist librarians for segmentation tasks.

THE DATA EXCHANGE IN THE PROCESS OF AUTOMATED SYNTHESIS OF THE FINITE-ELEMENT MODEL OF WING BOX OF THE TRANSPORT CATEGORY AIRCRAFT

For the solving of task of optimization of power structure of wing box of transport aircraft the analysis of significant volume of random variants of wing box element composition is needed. The most effective method for modeling the elastic properties of random structures and analyzing their stress-strain state under the action of random loads is the finite element method. In this case, the complexity of the structure of the finite element model (the number of elements and the number of links between elements) is comparable to the complexity of the model being modeled. In modern CAD-systems this problem is solved with the help of the decomposition method. In accordance with this method, the process of creating a common structure model is transformed into relatively independent processes for creating models of structure elements. At that there is a problem of coordination the parameters of local models, without the solution of which the synthesis of the common model is impossible.Unlike 3D models, the process of combining local finite element models include the change in their internal data. That is, the data exchange between local models is also performed in the process of synthesis of the common finite element model. The article investigates the schemes of data exchange between the local finite element models of structure elements of transport aircraft at the synthesis of common finite element model wing box.It is shown that when using the method of automatic building of finite elements on the basis of geometric models of structure elements on which all modern CAE systems are based, the number of decomposition levels is limited to two. The use of the substructures (superelements) method significantly expands the capabilities of CAE-systems in the modeling of complex structures, since the division of the general geometric model into several parts increases the number of levels of its decomposition to three. Increase the number of levels of decomposition makes it possible to divide the process of building of local geometric by transferring each part of the common model to separate specialist. As a result, the time of building of local finite-element models is reduced. At that, the synthesis of finite element models of fragments of the common geometric model is first performed, which are then combined into a common model. Unlike CAD-systems, CAE-systems do not have an interface with database management systems and do not support the required functions of data management. This significantly complicates the process of coordination models of substructures.It is shown that to solve the problem of data exchange in the process of synthesis of the finite-element model of the wing box, it is necessary to use individual algorithms for models of each class of structural elements. At that the data exchange must take place in an automatic mode. Implementation of these conditions is possible only with the use of object-oriented information technologies and, in particular, object-oriented systems for project data management.

Structural coupling across the direct EuO/Si interface

The ferromagnetic semiconductor EuO is believed to be an effective spin injector when directly integrated with silicon (Si). Injection through spin-selective ohmic contact requires superb structural quality of the interface EuO/Si. A recent breakthrough in manufacturing free-of-buffer-layer EuO/Si junctions calls for structural studies of the interface between the semiconductors. The synthesis of EuO employs an advanced protection of the Si substrate surface and a two-step growth protocol. It prevents unwanted chemical reactions at the interface. Ex situ high-resolution x-ray diffraction (XRD) and reflectivity (XRR) accompanied by in situ reflection high-energy electron diffraction reveal direct coupling at the interface. A combined analysis of XRD and XRR data provides a common structural model. The structural quality of the EuO/Si spin contact far exceeds that of previous reports and thus makes a step forward to the ultimate goals of spintronics.

On the limit of conditional Spearman’s rho under the common factor model

Under the common factor structural model of credit risk, we study a limit of a conditional Spearman’s rho coefficient. The conditioning event is that the common factor stays below a threshold and the limit is taken as the threshold tends to −∞. The main result is established through a relation with the classical theory of regular variation. We identify the relationship between the limiting Spearman’s rho and the tail thickness of the distribution function of the common factor. In particular, a necessary condition for the limiting Spearman’s rho to be strictly less than 1, is that the inverse cumulative distribution function of the common random variable is slowly varying at zero. As an illustration, the calculation of Stress Value-at-Risk for portfolio credit losses is discussed.

Another View on U.S. Treasury Term Premiums

The consensus suggests that subdued nominal U.S. Treasury yields, on balance since the onset of the global financial crisis, primarily reflect exceptionally low, if not negative at times, term premiums as opposed to low anticipated short rates. Depressed term premiums plausibly owe to unconventional Federal Reserve policy as well as net flight-to-quality flows during the period. However, two strands of evidence raise questions about this story. First, a purely survey-based expected forward term premium measure, as opposed to an approximate spot estimate, has increased rather than decreased in recent years. Second, with respect to the timeseries dynamics of common affine term structure model (ATSM) factors, simple econometrics of recent data produce not only a more persistent level of the term structure, but also a depressed long-run mean, which in turn implies an implausibly low expected short rate path. Strong caveats aside, an implication for central bankers is that unconventional monetary policy measures may have worked in more conventional ways, and an inference for investors is that longer-dated yields embed meaningful compensation for bearing duration risk.

Agreement among graders on Heidelberg retina tomograph (HRT) topographic change analysis (TCA) glaucoma progression interpretation

PurposeTo evaluate agreement among experts of Heidelberg retina tomography's (HRT) topographic change analysis (TCA) printout interpretations of glaucoma progression and explore methods for improving agreement.Methods109 eyes of glaucoma, glaucoma suspect...

Prediction and Simulation Research of Improved Search Engine Algorithm and Model Ftting

With the number of college graduates is increasing year by year, digital information management for the employment of college graduates receives more and more attention of managers in colleges and universities. Establishing management information system of college graduates employment is imperative. In this paper we first discuss the theoretical concept and the common structure model of employment information management system, then according to the demand of college graduates employment and enterprise recruitment requirements design the college graduates employment management system based on Web. The system includes the graduate information management systems, enterprise information management system, recruitment information query system, students landing system. Finally, we test and do simulation on operation of the system. The result shows that the university graduates employment management system has the advantages of simple operation, safe and reliable operation. It builds a platform for the exchange of information among the university, graduates, enterprise, which facilitate the management of graduates.

English Law Terms: Optimizing Education Process

The article focuses on the terminology of English law as a system. It deals with the main specific characteristics of the English legal terminology and studies the systemic nature of the terminology of Criminal Law. Nowadays, an increasing role of the study of professional language (Language for Specific Purposes) is obvious since it is a means of dissemination and exchange of professional information and a means of communication in the professional discourse. It is a system of terms that constitutes the core of the Language for Specific Purposes. The study of terminology is of paramount importance for the legal sphere of human activity where the accuracy of interpretation plays a very substantial part. Legal terms have a number of specific characteristics, such as: abstract nature of legal notions; introduction of new terms by regulatory organizations; an important role of judicial interpretation in constituting shades of meaning of a legal terminological unit; and the fact that a legal term may belong to a particular area of Law, which makes it possible to refer it to the category of general legal, branch-wise, or inter-branch vocabulary. Every term has its particular place among other elements of a system and is related to them in a particular way. A terminological system should be considered as a whole, and there are particular hierarchical relations between its elements. Within a terminological system, it is possible to seta hierarchy of generic and specific terms that can form the so-called semantic field. One of the features demonstrating the systemic links within a terminology is the existence of some typical structural models, according to which terms are coined. An important criterion is the predominance ofterminological word-combinations of a certain type. For example, in the terminology of Criminal Law the models Noun + Preposition + Noun and Adjective + Noun are the most common structural models. Another important criterion of a systemic nature of terminology is the existence of antonymous relations between terminological units. Undoubtedly, systemic approach to terminological studies allows optimizing the learning process.

How many pathways underlie socioeconomic differences in the development of cognition and achievement?

Children whose parents are more highly educated enjoy greater age-linked gains in cognitive abilities and academic achievement. Different researchers have typically focused on different outcomes, and the extent to which parental education relates to multiple child outcomes via a single developmental pathway has received little empirical attention. This issue was examined by applying common factor structural equation models to a large (N=4810) nationally representative sample of kindergarten through 12th grade children, who were measured on 6 distinct cognitive abilities and 5 distinct forms of knowledge and academic achievement. Results indicated that a single pathway accounted for the relations between parental education and age differences in children's cognitive abilities. However, additional unique pathways were necessary to account for the relations between parental education and age differences in academic knowledge and mathematics. These results suggest that while socioeconomic differences are largely manifested in global aspects of cognitive development, they have incremental relations with some forms of academic achievement.

Propriedades das Séries Temporais dos Lucros Trimestrais das Empresas Brasileiras Negociadas em Bolsa

Apesar de assunto muito debatido no exterior desde os anos 1960, principalmente nos Estados Unidos, a literatura sobre as propriedades das séries temporais de lucros é praticamente inexistente no Brasil. Desta forma, procurando preencher esta lacuna, o presente artigo analisa o comportamento das séries temporais de lucros trimestrais (operacional e líquido) de uma amostra de 109 empresas brasileiras com ações negociadas em bolsa, durante o período de 1995 a 2008. Foram utilizados cinco modelos de previsão de séries de lucros já previamente estimados e consagrados na literatura internacional, denominados aqui de modelos predeterminados, bem como foi empregado o método de Box e Jenkins (BJ) para verificar a possibilidade de se encontrar um modelo mais adequado às condições do mercado brasileiro. Verifica-se que somente o lucro operacional é passível de previsão, não sendo possível a aplicabilidade do método de BJ ao lucro líquido, pois este apresenta, na amostra estudada, um comportamento aleatório, descrito por um random walk com deslocamento. Conclui-se, também, que não existe um modelo ARIMA predeterminado que seja aplicável ao conjunto das empresas estudadas. Um modelo deve ser identificado individualmente para cada empresa.

Exploring the possibility of a common structural model measuring associations between safety climate factors and safety behaviour in health care and the petroleum sectors

The aim of the present study was to explore the possibility of identifying general safety climate concepts in health care and petroleum sectors, as well as develop and test the possibility of a common cross-industrial structural model. Self-completion questionnaire surveys were administered in two organisations and sectors: (1) a large regional hospital in Norway that offers a wide range of hospital services, and (2) a large petroleum company that produces oil and gas worldwide. In total, 1919 and 1806 questionnaires were returned from the hospital and petroleum organisation, with response rates of 55 percent and 52 percent, respectively. Using a split sample procedure principal factor analysis and confirmatory factor analysis revealed six identical cross-industrial measurement concepts in independent samples—five measures of safety climate and one of safety behaviour. The factors’ psychometric properties were explored with satisfactory internal consistency and concept validity. Thus, a common cross-industrial structural model was developed and tested using structural equation modelling (SEM). SEM revealed that a cross-industrial structural model could be identified among health care workers and offshore workers in the North Sea. The most significant contributing variables in the model testing stemmed from organisational management support for safety and supervisor/manager expectations and actions promoting safety. These variables indirectly enhanced safety behaviour (stop working in dangerous situations) through transitions and teamwork across units, and teamwork within units as well as learning, feedback, and improvement. Two new safety climate instruments were validated as part of the study: (1) Short Safety Climate Survey (SSCS) and (2) Hospital Survey on Patient Safety Culture-short (HSOPSC-short). Based on development of measurements and structural model assessment, this study supports the possibility of a common safety climate structural model across health care and the offshore petroleum industry.

Integrin Activation Dynamics between the RGD-binding Site and the Headpiece Hinge

Integrins form mechanical links between the extracellular matrix and the cytoskeleton. Although integrin activation is known to be regulated by an allosteric conformational change, which can be induced from the extracellular or intracellular end of the molecule, little is known regarding the sequence of structural events by which signals propagate between distant sites. Here, we reveal with molecular dynamics simulations of the FnIII(10)-bound alpha(V)beta(3) integrin headpiece how the binding pocket and interdomain betaA/hybrid domain hinge on the distal end of the betaA domain are allosterically linked via a hydrophobic T-junction between the middle of the alpha1 helix and top of the alpha7 helix. The key results of this study are: 1) that this T-junction is induced by ligand binding and hinge opening, and thus displays bidirectionality; 2) that formation of this junction can be accelerated by ligand-mediated force; and 3) how formation of this junction is inhibited by Ca(2+) in place of Mg(2+) at the site adjacent to the metal ion-dependent adhesion site ("ADMIDAS"). Together with recent experimental evidence that integrin complexes can form catch bonds (i.e. become strengthened under force), as well as earlier evidence that Ca(2+) at the ADMIDAS results in lower binding affinity, these simulations provide a common structural model for the dynamic process by which integrins become activated.

What Drives the Current Account in Commodity Exporting Countries? The Cases of Chile and New Zealand

This paper uses an open economy DSGE model with a commodity sector and nominal and real rigidities to ask what factors account for current account developments in two small commodity exporting countries. We estimate the model, using Bayesian techniques, on Chilean and on New Zealand data, and investigate the structural factors that explain the behaviour of the two countries' current accounts. We find that foreign financial conditions, investment-specific shocks, and foreign demand account for the bulk of the variation of the current accounts of the two countries. In the case of New Zealand fluctuations in commodity export prices have also been important. Monetary and fiscal policy shocks (deviations from policy rules) are estimated to have relatively small effects on the current account. We find interesting differences in Chilean and New Zealand responses to some shocks, despite similarities between the two economies and the common structural model employed.

An empirical study of factors impacting on knowledge processes in online forums: factors of interest and model outline

Based on a literature review of the fields of research of knowledge management, collaborative systems and online communities, this paper presents an outline of factors expected to contribute to collaborative knowledge creation and knowledge transfer processes in online forums, and proposes corresponding hypotheses. The paper depicts the model's underlying framework and its general methodological approach, describes the method for the indirect derivation of individual actor's knowledge process contributions, and expands in detail on input factors expected to contribute to knowledge process relevant contributions within online forums. Finally, the integration of these factors into a common Measurement and Structural Model is described. The research project is currently being conducted at International University Bremen (IUB).

Identification and Mutational Analysis of Amino Acid Residues Involved in Dipyridamole Interactions with Human and Caenorhabditis elegans Equilibrative Nucleoside Transporters

The equilibrative nucleoside transporters, hENT1 and CeENT1 from humans and Caenorhabditis elegans, respectively, are inhibited by nanomolar concentrations of dipyridamole and share a common 11-transmembrane helix (TM) topology. Random mutagenesis and screening by functional complementation in yeast for clones with reduced sensitivities to dipyridamole yielded mutations at Ile429 in TM 11 of CeENT1 and Met33 in TM 1 of hENT1. Mutational analysis of the corresponding residues of both proteins suggested important roles for these residues in competitive inhibition of hENT1 and CeENT1 by dipyridamole. To verify the roles of these residues in dipyridamole interactions, hENT2, which naturally exhibits low dipyridamole sensitivity, was mutated to contain side chains favorable for high affinity dipyridamole binding (i.e. a Met at the TM 1 and/or an Ile at the TM 11 positions). The single mutants exhibited increased hENT2 sensitivity to inhibition by dipyridamole, and the double mutant was the most sensitive, with an IC50 value that was only 2% of that of wild type. Functional analysis of the TM 1 and 11 mutants of hENT1 and CeENT1 revealed that Ala and Thr in the TM 1 and 11 positions, respectively, impaired uridine and adenosine transport and that Leu442 of hENT1 was involved in permeant selectivity. Mechanistic and structural models of dipyridamole interactions with the TM 1 and 11 residues are proposed. This study demonstrated that the corresponding residues in TMs 1 and 11 of hENT1, hENT2, and CeENT1 are important for dipyridamole interactions and nucleoside transport.

Structural changes in higher education systems in Western Europe

This article gives an overview and analysis of structural changes of higher education systems in Western Europe, and how the various countries have changed their systems over the last four decades. Emphasis is placed on the development of a non‐university higher education sector in most countries. The question to be discussed is the extent to which the various countries converge to a common structural model for the organization of higher education – either a binary system which is the most common model today, or a unified but hierarchical system as in the United Kingdom.

Insights into the subunit interactions of the chloroplast ATP synthase

Subunit interactions of the chloroplast F0F1-ATP synthase were studied using the yeast two-hybrid system. The coding sequences of all the nine subunits of spinach chloroplast ATP synthase were cloned in two-hybrid vectors. The vectors were transformed into the yeast strains HF7c and SFY526 by various pairwise combinations, and the protein interactions were analyzed by measuring the yeast growth on minimal SD medium without serine, lucine and histidine. Interactions of γ subunit with wild type or two truncated mutants of e sununit, eΔN21 and eΔC45, which lose their abilities to inhibit the ATP hydrolysis, were also detected by in vitro and in vivo binding assay. The present results are largely accordant to the common structure model of F0F1-ATP synthase. Different from that in the E. coli F0F1-ATP synthase, the δ subunit of chloroplast ATP synthase could interact with β, γ, e and all the CF0 subunits in the two-hybrid system. These results suggested that though the chloroplast ATP synthase shares the similar structure and composition of subunits with the enzyme from E. coli, it may be different in the subunit interactions and conformational change during catalysis between these two sources of ATP synthase. Based on the present results and our knowledge of structure model of E. coli ATP synthase, a deduced structure model of chloroplast ATP synthase was proposed.

Modelling customer satisfaction and loyalty on aggregate levels: Experience from the ECSI pilot study

Aggregate Customer Satisfaction Index (CSI) measures are becoming more and more common as indicators of business performance in different industries, and are used for a multitude of purposes. However, any comparison of such figures from one domain to another calls for tightly harmonized and co-ordinated methodological frameworks. In this paper we study the prerequisites for developing a common model structure useful for devising aggregate CSI results throughout Europe, and comparing also with similar efforts in other parts of the world. Our study is based on an evaluation of the stability and robustness of empirical results from the European Customers, Satisfaction Index (ECSI) pilot survey round. In spite of the fact that European customers, product supplies and cultural environments are different, it is found possible to specify a common structural model to be used in such diverse industries as telecoms, banking and supermarkets, throughout 11 European countries. This model is not optimal in the majority of cases (in terms of explanatory power), but neither in any case is it very far away from fulfilling high quality criteria. Thus, it fulfils the pre-specified requirements in terms of robustness, and is proposed to be used as the standard in future Pan-European activities of this character. In the second part of the paper the prerequisites for finding adequate manifest (measurable) variables for the structural latent variable model are very briefly considered. A comprehensive factor analysis study of all ECSI pilot corporate models (about 150) is scrutinized. The results of this study are rather comforting in terms of generating adequate factors (similar to the ones predefined as latent variables) and using a common (master) measurement instrument (questionnaire). However, for a few latents (especially perceived value) certain problems of measurement are identified.

Structural Model of the Catalytic Core of Carnitine Palmitoyltransferase I and Carnitine Octanoyltransferase (COT): MUTATION OF CPT I HISTIDINE 473 AND ALANINE 381 AND COT ALANINE 238 IMPAIRS THE CATALYTIC ACTIVITY

Carnitine palmitoyltransferase I (CPT I) and carnitine octanoyltransferase (COT) catalyze the conversion of long- and medium-chain acyl-CoA to acylcarnitines in the presence of carnitine. We propose a common three-dimensional structural model for the catalytic domain of both, based on fold identification for 200 amino acids surrounding the active site through a threading approach. The model is based on the three-dimensional structure of the rat enoyl-CoA hydratase, established by x-ray diffraction analysis. The study shows that the structural model of 200 amino acids of the catalytic site is practically identical in CPT I and COT with identical distribution of 4 beta-sheets and 6 alpha-helices. Functional analysis of the model was done by site-directed mutagenesis. When the critical histidine residue 473 in CPT I (327 in COT), localized in the acyl-CoA pocket in the model, was mutated to alanine, the catalytic activity was abolished. Mutation of the conserved alanine residue to aspartic acid, A381D (in CPT I) and A238D (in COT), which are 92/89 amino acids far from the catalytic histidine, respectively (but very close to the acyl-CoA pocket in the structural model), decreased the activity by 86 and 80%, respectively. The K(m) for acyl-CoA increased 6-8-fold, whereas the K(m) for carnitine hardly changed. The inhibition of the mutant CPT I by malonyl-CoA was not altered. The structural model explains the loss of activity reported for the CPT I mutations R451A, W452A, D454G, W391A, del R395, P479L, and L484P, all of which occur in or near the modeled catalytic domain.