893,023 research outputs found

    The financial performance of an innovative megaproject

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    The financial structure of megaprojects, known in the literature as project finance, is characterized by the creation of a legally independent project company financed with a concentrated equity ownership and a high level of non-recourse debt. Research in this field may yield new ideas and theories about the existing theoretical framework on capital structure, stakeholder management and risk management. A case-study is analyzed in this paper: the financial performance of the first metro line in Seville (Spain). In spite of previous cost overruns in the construction stage, the present operation stage is considered successful from the point of view of social and financial profitability, whereby the risks have been theoretically transferred to stakeholders, as defined by Value for Money considerations. The objective of this study involves: first to determine whether this megaproject meets the expectations for which it was created in terms of hope of return of the shareholders, and the expectations of the economic and financial feasibility under a change of subsidy policies; and secondly to determine whether the conditions remain for not including the investment as public debt. This issue is crucial in a budgetary constraint context for the planning of future metro lines. By taking this first experience into account, this article also provides information for potential participants in the projects of the new metro lines, which are currently in the planning stage

    Introduction for the Special Issue on Beyond the Hypes of Geospatial Big Data: Theories, Methods, Analytics, and Applications

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    We live in the era of ‘Big Data’. In particular, Geospatial data, whether captured through remote sensors (e.g., satellite imagery) or generated from large-scale simulations (e.g., climate change models) have always been significantly large in size. Over the last decade however, advances in instrumentation and computation has seen the volume, variety, velocity, and veracity of this data increase exponentially. Of the 2.5 quintillion (1018) bytes of data that are generated on a daily basis across the globe, a large portion (arguably as much as 80%) is found to be geo-referenced. Therefore, this special issue is dedicated to the innovative theories, methods, analytics, and applications of geospatial big data

    Involvement of N-6 adenine-specific DNA methyltransferase 1 (N6AMT1) in arsenic biomethylation and its role in arsenic-induced toxicity.

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    BackgroundIn humans, inorganic arsenic (iAs) is metabolized to methylated arsenical species in a multistep process mainly mediated by arsenic (+3 oxidation state) methyltransferase (AS3MT). Among these metabolites is monomethylarsonous acid (MMAIII), the most toxic arsenic species. A recent study in As3mt-knockout mice suggests that unidentified methyltransferases could be involved in alternative iAs methylation pathways. We found that yeast deletion mutants lacking MTQ2 were highly resistant to iAs exposure. The human ortholog of the yeast MTQ2 is N-6 adenine-specific DNA methyltransferase 1 (N6AMT1), encoding a putative methyltransferase.ObjectiveWe investigated the potential role of N6AMT1 in arsenic-induced toxicity.MethodsWe measured and compared the cytotoxicity induced by arsenicals and their metabolic profiles using inductively coupled plasma-mass spectrometry in UROtsa human urothelial cells with enhanced N6AMT1 expression and UROtsa vector control cells treated with different concentrations of either iAsIII or MMAIII.ResultsN6AMT1 was able to convert MMAIII to the less toxic dimethylarsonic acid (DMA) when overexpressed in UROtsa cells. The enhanced expression of N6AMT1 in UROtsa cells decreased cytotoxicity of both iAsIII and MMAIII. Moreover, N6AMT1 is expressed in many human tissues at variable levels, although at levels lower than those of AS3MT, supporting a potential participation in arsenic metabolism in vivo.ConclusionsConsidering that MMAIII is the most toxic arsenical, our data suggest that N6AMT1 has a significant role in determining susceptibility to arsenic toxicity and carcinogenicity because of its specific activity in methylating MMAIII to DMA and other unknown mechanisms

    What is Life?

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    In searching for life in extraterrestrial space, it is essential to act based on an unequivocal definition of life. In the twentieth century, life was defined as cells that self-replicate, metabolize, and are open for mutations, without which genetic information would remain unchangeable, and evolution would be impossible. Current definitions of life derive from statistical mechanics, physics, and chemistry of the twentieth century in which life is considered to function machine like, ignoring a central role of communication. Recent observations show that context-dependent meaningful communication and network formation (and control) are central to all life forms. Evolutionary relevant new nucleotide sequences now appear to have originated from social agents such as viruses, their parasitic relatives, and related RNA networks, not from errors. By applying the known features of natural languages and communication, a new twenty-first century definition of life can be reached in which communicative interactions are central to all processes of life. A new definition of life must integrate the current empirical knowledge about interactions between cells, viruses, and RNA networks to provide a better explanatory power than the twentieth century narrative

    Tidying up international nucleotide sequence databases

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    Sequence analysis of the ribosomal RNA operon, particularly the internal transcribed spacer (ITS) region, provides a powerful tool for identification of mycorrhizal fungi. The sequence data deposited in the International Nucleotide Sequence Databases (INSD) are, however, unfiltered for quality and are often poorly annotated with metadata. To detect chimeric and low-quality sequences and assign the ectomycorrhizal fungi to phylogenetic lineages, fungal ITS sequences were downloaded from INSD, aligned within family-level groups, and examined through phylogenetic analyses and BLAST searches. By combining the fungal sequence database UNITE and the annotation and search tool PlutoF, we also added metadata from the literature to these accessions. Altogether 35,632 sequences belonged to mycorrhizal fungi or originated from ericoid and orchid mycorrhizal roots. Of these sequences, 677 were considered chimeric and 2,174 of low read quality. Information detailing country of collection, geographical coordinates, interacting taxon and isolation source were supplemented to cover 78.0%, 33.0%, 41.7% and 96.4% of the sequences, respectively. These annotated sequences are publicly available via UNITE (http://unite.ut.ee/) for downstream biogeographic, ecological and taxonomic analyses. In European Nucleotide Archive (ENA; http://www.ebi.ac.uk/ena/), the annotated sequences have a special link-out to UNITE. We intend to expand the data annotation to additional genes and all taxonomic groups and functional guilds of fungi

    Governance, rational choice and new public management (npm): a general view (and some critics)

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    This article aims to study the New Public Management (NPM), one of the main trends associated to neoliberalism. It studies governance to show its general, wider and abstract scope. It also focuses on the Rational Choice as an important theory about governance, a basis for NPM. And it observes the neoliberal foundations of NPM, showing critical aspects of its real practice. Methodology: hypothetical deductive method of research, with a qualitative and critical approach and bibliographic-documental research technique. As results of this research, we can conclude that: i) the ideological usage of NPM has been expressed in a culture of minimal state and government - but in practice, such culture, when embossing implemented reforms, seldom reverted the role of the state, destroyed social safety nets, and placed the tax burden on the working majority rather than on the wealthy elite; ii) advocates for NPM have Western-shaped minds, generally making erroneous assumptions about institutions and cultures, which may be present in Anglo-American countries, but not in other culturally different ones; iii) in practice, NPM reforms were imposed to low-income countries by donor institutions to adjust their states for good governance - but those reforms did not solve problems with inefficiency and corruption. This work is original and valuable because it shows that even when public policies highlight the importance of less state intervention, solid norms and institutions are always necessary, and because it helps demystifying discourses that simply put that less state/more market politics can be valuable everywhere

    Forecast of potentially dangerous rock pressure manifestations in the mine roadways by using information technology and radiometric control methods

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    Purpose. To reduce risk of emergency and injury-risk situations while improving the methods for predicting stress-strain state of the rock mass with the help of information systems, and to detect fissure locations in the mine roadways with the help of radiometric control. Methods. Analysis and generalization of experimental data; mathematical modeling of geomechanical and filtration processes by means of the finite element method; underground investigations of changes in activity of α-radiation of certain radon-isotope in the atmosphere of the mine roadways using standard methods as well as radiometric control equipment; and statistical processing of measurement results. Findings. Ratios, determining correlation between parameters of geomechanical process (i.e. fracture porosity, inclination angles of the fracture networks and their strike) and parameters of gas- dynamic process (i.e. intensity, gas flow rates and direction of gas travel) have been obtained. A mathematical model based on the finite element method is proposed in which a reasonable assumption is made that deformation of the pore medium is equal to the varied volume of the pore and fracture area. In the context of the model, deviation part of the strain tensor determines changes in the shape of the rock mass elements during disintegration. Spherical part of the strain tensor characterizes changes in volume and permeability of the pore and fracture area; it is determined by a value of minimum principal strains of the model elements. Parameters of the pore and fracture area location, volume and permeability were substantiated in the rock mass. The mine investigations have helped determine that within the areas of geological dislocations, concentration of radon daughter decay product of alpha-radiation polonium (Po218) experiences more that 2 – 4 times increase in relation to the roadway average value. On the basis of the criterion, it is proposed to use radiation monitoring of the mine roadways to identify areas of newly formed fracture systems resulting from fracture system deformation as one of the elements of method for the integrated control of the rock mass state. Originality. For the first time, regularities of changes in the pore and fracture area shape and volume at different stages of the adjacent longwall mining have been determined basing on parameters of technogenic fracture system orientation and spherical part of the strain tensor. The method of controlling the safe state of rocks has been further developed; it differs in the use of the determined ratios between changes in fracture system parameters and changes in α-radiation activity of some radon isotopes, methane concentrations and their correlation. Practical implications. The research results have been applied for the development of analytical and experimental approach to control safety of production environment in mines.Мета. Знизити ризики виникнення аварійних і травмонебезпечних ситуацій в шахтах шляхом вдосконалення методів прогнозу напружено-деформованого стану масиву порід із використанням інформаційних систем та виявлення локацій тріщин у гірничих виробках методом радіометричного контролю. Методика. Аналіз і узагальнення експериментальних даних; математичне моделювання геомеханічних і фільтраційних процесів методом скінченних елементів; шахтні дослідження змін активності α-випромінювань окремих ізотопів радону в атмосфері гірничих виробок стандартними методами та апаратурою радіометричного контролю; статистична обробка результатів вимірювань. Результати. Отримані співвідношення, що встановлюють взаємозв’язки параметрів геомеханічного процесу (тріщиною пористістю, кутами падіння і простягання систем тріщин) з параметрами газодинамічного процесу (інтенсивністю, витратами та напрямком переміщення газів). Запропоновано математичну модель на базі методу скінченних елементів, в якій прийнято обґрунтоване припущення, що деформація пористого середовища дорівнює зміні об’ємів порово-тріщинного простору. У моделі девіаторна частина тензора деформацій визначає зміни форми елементів породного масиву в процесі руйнування. Кульова частина тензора деформацій характеризує зміни об’єму і проникності порово-трещинного простору та визначається величиною мінімальних головних деформацій елементів моделі. Обґрунтовані параметри розташування, об’ємів і проникності порово-тріщинного простору в масиві порід. Шахтними дослідженнями встановлено, що в місцях дислокації геологічних порушень концентрація дочірнього продукту розпаду радону α-випромінювання полонію (Po218) зростає більш ніж в 2 – 4 рази по відношенню до середнього по виробці значення. На базі вказаного критерію запропоновано використовувати радіометричний моніторинг гірничих виробок для виявлення локацій новоутворених в процесі деформування систем тріщин в якості одного з елементів методу комплексного контролю стану породного масиву. Наукова новизна. Вперше на базі параметрів орієнтації систем тріщин техногенного походження й кульової частини тензора деформацій встановлені закономірності змін форми та об’ємів порово-тріщинного простору на різних етапах відпрацювання суміжних лав. Подальший розвиток отримав метод контролю безпечного стану гірських порід, який відрізняється використанням встановлених взаємозв’язків між змінами параметрів систем тріщин та змінами активності α-випромінювань окремих ізотопів радону, концентрацій метану і їх співвідношень. Практична значимість. Наукові результати використані при розробці аналітико-експериментального методу контролю безпеки виробничого середовища шахт.Цель. Снизить риски возникновения аварийных и травмоопасных ситуаций в шахтах путем совершенствования методов прогноза напряженно-деформированного состояния массива пород с использованием информационных систем и выявления локаций образовавшихся трещин в горных выработках методом радиометрического контроля. Методика. Анализ и обобщение экспериментальных данных; математическое моделирование геомеханических и фильтрационных процессов методом конечных элементов; шахтные исследования изменений активности α-излучений отдельных изотопов радона в атмосфере горных выработок стандартными методами и аппаратурой радиометрического контроля; статистическая обработка результатов измерений. Результаты. Получены соотношения, устанавливающие взаимосвязи параметров геомеханического процесса (трещинной пористостью, углами падения и простирания систем трещин) с параметрами газодинамического процесса (интенсивностью, расходами и направлением перемещения газов). Предложена математическая модель на базе метода конечных элементов, в которой принято обоснованное допущение, что деформация пористой среды равна изменению объема порово-трещинного пространства. В модели девиаторная часть тензора деформаций определяет изменение формы элементов породного массива в процессе разрушения. Шаровая часть тензора деформаций характеризует изменения объема и проницаемости порово-трещинного пространства и определяется величиной минимальных главных деформаций элементов модели. Обоснованы параметры расположения, объемов и проницаемости порово-трещинного пространства в массиве пород. Шахтными исследованиями установлено, что в местах дислокации геологических нарушений концентрация дочернего продукта распада радона α-излучения полония (Po218) возрастает более чем в 2 – 4 раза по отношению к среднему по выработке значению. На базе указанного критерия предложено использовать радиометрический мониторинг горных выработок для выявления локаций вновь образовавшихся в процессе деформирования систем трещин в качестве одного из элементов метода комплексного контроля состояния породного массива. Научная новизна. Впервые на базе параметров ориентации систем трещин техногенного происхождения и шаровой части тензора деформаций установлены закономерности изменений формы и объемов порово-трещинного пространства на различных этапах отработки смежных лав. Дальнейшее развитие получил метод контроля безопасного состояния горных пород, который отличается использованием установленных взаимосвязей между изменениями параметров систем трещин и изменениями активности α-излучения отдельных изотопов радона, концентраций метана и их соотношений. Практическая значимость. Научные результаты использованы при разработке аналитико-эксперимен-тального метода контроля безопасности производственной среды шахт.The authors express their gratitude to the Director of the Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine, Academician of the National Academy of Sciences of Ukraine, Professor A.F. Bulat for providing technical and informational support for the research
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