56 research outputs found

    Interpolatory Weighted-H2 Model Reduction

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    This paper introduces an interpolation framework for the weighted-H2 model reduction problem. We obtain a new representation of the weighted-H2 norm of SISO systems that provides new interpolatory first order necessary conditions for an optimal reduced-order model. The H2 norm representation also provides an error expression that motivates a new weighted-H2 model reduction algorithm. Several numerical examples illustrate the effectiveness of the proposed approach

    Pulse perturbation technique for determination of piroxicam in pharmaceuticals using an oscillatory reaction system

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    A simple and reliable novel kinetic method for the determination of piroxicam (PX) was proposed and validated. For quantitative determination of PX, the Bray-Liebhafsky (BL) oscillatory reaction was used in a stable non-equilibrium stationary state close to the bifurcation point. Under the optimized reaction conditions (T = 55.0A degrees C, [H2SO4](0) = 7.60x10(-2) mol L-1, [KIO3](0) = 5.90x10(-2) mol L-1, [H2O2](0) = 1.50x10(-1) mol L-1 and j (0) = 2.95x10(-2) min(-1)), the linear relationship between maximal potential shift Delta E (m) , and PX concentration was obtained in the concentration range 11.2-480.5 A mu g mL(-1) with a detection limit of 9.9 A mu g mL(-1). The method had a rather good sample throughput of 25 samples h(-1) with a precision RSD = 4.7% as well as recoveries RCV a parts per thousand currency sign 104.4%. Applicability of the proposed method to the direct determination of piroxicam in different pharmaceutical formulations (tablets, ampoules and gel) was demonstrated

    Restorative Treatment Decisions of Dentists in Split and Dalmatia County on Approximal and Occlusal Caries: a Pilot Study

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    Svrha istraživanja: Zadatak ovog eksperimentalnog istraživanja bio je odrediti dubinu aproksimalnih i okluzalnih karijesnih lezija kod kojih se stomatolozi na području Splitsko-dalmatinske županije odlučuju za restaurativni tretman te vrste preparacija i materijale koje za to odabiru. Materijali i metoda: Upitnik koji su sastavili Espelid i suradnici (2001.) preveden je s engleskoga jezika na hrvatski i podijeljen slučajno odabranom uzorku (n=100) stomatologa u Splitsko-dalmatinskoj županiji. Ispunilo ga je njih 28. Na slikama u upitniku bili su prikazani različiti klinički i radiološki stadiji aproksimalnih, okluzalnih i upitnih karijesnih lezija. Rezultati: Većina stomatologa odlučila se za restaurativni tretman aproksimalnih karijesnih lezija koje su dosegnule caklinsko-dentinsko spojište (39%) ili vanjsku trećinu dentina (39%). Za aproksimalnu karijesnu leziju 61 posto stomatologa odabrao je tunelsku preparaciju. Otvaranje okluzalne karijesne lezije u dentinu bio je izbor njih 75 posto. Većina (46%) odgovorila je da zub A ima karijesnu leziju u caklini, a 39 posto smatralo je da zub B nema karijesnu leziju. Zaključak: Stomatolozi Splitsko-dalmatinske županije odlučuju se za restaurativni tretman u trenutku kada karijesna lezija dosegne caklinsko-dentinsko spojište ili vanjsku trećinu dentina, ali su potrebna daljnja istraživanja na većem broju ispitanika.Objective of work: The aim of this pilot study was to identify treatment thresholds, restorative methods and materials for approximal and occlusal caries lesions used by dentists in Split and Dalmatia County. Materials and Methods: The questionnaire of Espelid et al. (2001) was translated from English to Croatian and distributed to a random sample (n=100) of dentists in Split and Dalmatia County. Responses were collected from 28 dentists. Figures, included as an addition to questions, illustrated different clinical and radiographic stages of approximal, occlusal and questionable carious lesions. Results: The majority of dentists would perform restorative treatment for an approximal carious lesion which reached dentin-enamel junction (39%) or would not restore the lesion until it penetrated dentin (39%). The preferred cavity design was the tunnel preparation technique chosen by 61% of dentists. The majority of dentists (75%) stated that they would intervene restoratively for occlusal carious lesions in dentin. The majority (46%) of the dentists judged tooth A like having a carious lesion confined to the enamel while tooth B was judged “sound” by 39% of the respondents. Conclusions: Dentists in this pilot study tend to restore carious lesions at the moment the lesions reached dentin-enamel junction or just penetrated dentin, but further studies are necessary to conclude about the restorative decisions of dentists in Split and Dalmatia County

    Characteristics and drivers of forest cover change in the post-socialist era in Croatia: evidence from a mixed-methods approach

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    © 2016, Springer-Verlag Berlin Heidelberg.Extensive forests in Croatia represent an important biological and economic resource in Europe. They are characterised by heterogeneity in forest management practices dating back to the socialist planned economy of the pre-1991 era. In this study we investigated the difference in rates of deforestation and reforestation in private- and state-owned forests during the post-socialist period and the causal drivers of change. The selected region of Northern Croatia is characterised by a high percentage of privately owned forests with minimal national monitoring and control. We used a mixed-methods approach which combines remote sensing, statistical modelling and a household-based questionnaire survey to assess the rates of forest cover change and factors influencing those changes. The results show that predominantly privately owned forests in Northern Croatia have recorded a net forest loss of 1.8 % during the 1991–2011 period, while Croatia overall is characterised by a 10 % forest cover increase in predominantly state-owned forests. Main factors influencing forest cover changes in private forests are slope, altitude, education structure, population age and population density. The results also show that the deforestation in private forests is weakening overall, mostly due to the continuation of the de-agrarisation and de-ruralisation processes which began during socialism

    Genetic Differentiation of the Western Capercaillie Highlights the Importance of South-Eastern Europe for Understanding the Species Phylogeography

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    The Western Capercaillie (Tetrao urogallus L.) is a grouse species of open boreal or high altitude forests of Eurasia. It is endangered throughout most mountain range habitat areas in Europe. Two major genetically identifiable lineages of Western Capercaillie have been described to date: the southern lineage at the species' southernmost range of distribution in Europe, and the boreal lineage. We address the question of genetic differentiation of capercaillie populations from the Rhodope and Rila Mountains in Bulgaria, across the Dinaric Mountains to the Slovenian Alps. The two lineages' contact zone and resulting conservation strategies in this so-far understudied area of distribution have not been previously determined. The results of analysis of mitochondrial DNA control region sequences of 319 samples from the studied populations show that Alpine populations were composed exclusively of boreal lineage; Dinaric populations of both, but predominantly (96%) of boreal lineage; and Rhodope-Rila populations predominantly (>90%) of southern lineage individuals. The Bulgarian mountains were identified as the core area of the southern lineage, and the Dinaric Mountains as the western contact zone between both lineages in the Balkans. Bulgarian populations appeared genetically distinct from Alpine and Dinaric populations and exhibited characteristics of a long-term stationary population, suggesting that they should be considered as a glacial relict and probably a distinct subspecies. Although all of the studied populations suffered a decline in the past, the significantly lower level of genetic diversity when compared with the neighbouring Alpine and Bulgarian populations suggests that the isolated Dinaric capercaillie is particularly vulnerable to continuing population decline. The results are discussed in the context of conservation of the species in the Balkans, its principal threats and legal protection status. Potential conservation strategies should consider the existence of the two lineages and their vulnerable Dinaric contact zone and support the specificities of the populations

    Perturbations of the Dushman Reaction with Piroxicam: Experimental and Model Calculations

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    Perturbation of the BrayLiebhafsky non-oscillating subsystem (mixture of KIO3 and H2SO4), i.e., Dushman reaction (DR), by piroxicam (PX), was observed in an open reactor, i.e., in the continuously fed well-stirred tank reactor (CSTR). Monitoring the response of DR to perturbations by different concentrations of PX allows developing a simple procedure for quantitative determination of this analyte in both bulk drug and pharmaceutical preparation (injection). A tentative perturbation mechanism of PX action on the DR matrix, based on a kinetic scheme that was suggested by Agreda etal., is proposed. The PX reactivity in DR has been generally related to the reaction of PX with hypoiodous acid (HIO) present in the matrix
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