bluuebunny/crossref_metadata_2025 huggingface dataset:
Pour que les étudiants de FLS comprennent et participent à la francophonie canadienne
Authors: Thibault Laurence Valérie , Dansereau Marie-Claude , Lamoureux Sylvie
Published: July 2015

Le présent article est issu d’un atelier qui, à la lumière de résultats probants de deux recherches complémentaires sur les parcours pédagogiques de futurs enseignants de français langue seconde, présente deux réflexions de pratique d’enseignement du FLS en milieu universitaire. La recherche constate le manque de littératie culturelle et linguistique—notamment concernant la francophonie canadienne—des futurs enseignants de français parmi lesquels se trouvent des apprenants avancés de français langue seconde (FLS) (Lamoureux et Cohen, 2012; Moor et Lamoureux, 2012). Deux réflexions de pratique illustrent comment développer cette littératie dans un programme universitaire de FLS. La première traite du développement des compétences interculturelles (Byram, 2003) et présente des projets pédagogiques permettant aux étudiants de participer à la francophonie canadienne de manière autonome et éclairée. La deuxième porte sur l’importance d’accorder une valeur didactique à la compréhension des variétés locales de la langue pour mieux conscientiser les étudiants à la fonction symbolique de celle-ci (Cuq et Gruca, 2002) et les amener à communiquer avec les locuteurs natifs de manière plus autonome.
Position and Orientation Distributions for Non-Reversal Random Walks using Space-Group Fourier Transforms
Authors: Chirikjian Gregory S. , Skliros Aris
Published: July 2015

This paper presents an efficient group-theoretic approach for computing the statisticsof non-reversal random walks (NRRW) on lattices. These framed walks evolve on proper crystallographicspace groups. In a previous paper we introduced a convolution method for computingthe statistics of NRRWs in which the convolution product is defined relative to the space-groupoperation. Here we use the corresponding concept of the fast Fourier transform for functions oncrystallographic space groups together with a non-Abelian version of the convolution theorem. Wedevelop the theory behind this technique and present numerical results for two-dimensional andthree-dimensional lattices (square, cubic and diamond). In order to verify our results, the statisticsof the end-to-end distance and the probability of ring closure are calculated and compared withresults obtained in the literature for the random walks for which closed-form expressions exist.
Connectivity for 3 x 3 x K contingency tables
Authors: Sumi Toshio , Sakata Toshio
Published: July 2015

We consider an exact sequential conditional test for three-way conditional test of nointeraction. At each time , the test uses as the conditional inference frame the set F(H ) of alltables with the same three two-way marginal tables as the obtained table H . For 33K tables,we propose a method to construct F(H ) from F(H􀀀1). This enables us to perform ecientlythe sequential exact conditional test. The subset S of F(H ) consisting of s + H 􀀀 H􀀀1 fors 2 F(H􀀀1) contains H , where the operations + and 􀀀 are dened elementwise. Our argumentis based on the minimal Markov basis for 3 3 K contingency tables and we give a minimalsubset M of some Markov basis which has the property that F(H ) = fs 􀀀 m j s 2 S ;m 2 Mg.
Bayesian Fusion on Lie Groups
Authors: Wolfe Kevin C. , Mashner Michael
Published: July 2015

An increasing number of real-world problems involve the measurement of data, andthe computation of estimates, on Lie groups. Moreover, establishing confidence in the resultingestimates is important. This paper therefore seeks to contribute to a larger theoretical frameworkthat generalizes classical multivariate statistical analysis from Euclidean space to the setting of Liegroups. The particular focus here is on extending Bayesian fusion, based on exponential familiesof probability densities, from the Euclidean setting to Lie groups. The definition and properties ofa new kind of Gaussian distribution for connected unimodular Lie groups are articulated, and ex-plicit formulas and algorithms are given for finding the mean and covariance of the fusion modelbased on the means and covariances of the constituent probability densities. The Lie groups thatfind the most applications in engineering are rotation groups and groups of rigid-body motions.Orientational (rotation-group) data and associated algorithms for estimation arise in problemsincluding satellite attitude, molecular spectroscopy, and global geological studies. In robotics andmanufacturing, quantifying errors in the position and orientation of tools and parts are impor-tant for task performance and quality control. Developing a general way to handle problemson Lie groups can be applied to all of these problems. In particular, we study the issue of howto ‘fuse’ two such Gaussians and how to obtain a new Gaussian of the same form that is ‘closeto’ the fused density.This is done at two levels of approximation that result from truncating theBaker-Campbell-Hausdorff formula with different numbers of terms. Algorithms are developedand numerical results are presented that are shown to generate the equivalent fused density withgood accuracy
L-cumulants, L-cumulant embeddings and algebraic statis- tics
Authors: Zwiernik Piotr
Published: July 2015

Focusing on the discrete probabilistic setting we generalize the combinatorial denitionof cumulants to L-cumulants. This generalization keeps all the desired properties of the classicalcumulants like semi-invariance and vanishing for independent blocks of random variables. Theseproperties make L-cumulants useful for the algebraic analysis of statistical models. We illustratethis for general Markov models and hidden Markov processes in the case when the hidden processis binary. The main motivation of this work is to understand cumulant-like coordinates in algebraicstatistics and to give a more insightful explanation why tree cumulants give such an elegantdescription of binary hidden tree models. Moreover, we argue that L-cumulants can be used in theanalysis of certain classical algebraic varieties.
Learning Coefficient in Bayesian Estimation of Restricted Boltzmann Machine
Authors: Aoyagi Miki
Published: July 2015

We consider the real log canonical threshold for the learning model in Bayesian estimation.This threshold corresponds to a learning coefficient of generalization error in Bayesianestimation, which serves to measure learning efficiency in hierarchical learning models [30, 31, 33].In this paper, we clarify the ideal which gives the log canonical threshold of the restricted Boltzmannmachine and consider the learning coefficients of this model.
On Polyhedral Approximations of Polytopes for Learning Bayesian Networks
Authors: Studený Milan , Haws David C.
Published: July 2015

The motivation for this paper is the geometric approach to statistical learning Bayesiannetwork (BN) structures. We review three vector encodings of BN structures. The first one hasbeen used by Jaakkola et al. [9] and also by Cussens [4], the other two use special integral vectorsformerly introduced, called imsets [18, 20]. The topic is the comparison of outer polyhedral approximationsof the corresponding polytopes. We show how to transform the inequalities suggested byJaakkola et al. [9] into the framework of imsets. The result of our comparison is the observationthat the implicit polyhedral approximation of the standard imset polytope suggested in [21] givesa tighter approximation than the (transformed) explicit polyhedral approximation from [9]. Asa consequence, we confirm a conjecture from [21] that the above-mentioned implicit polyhedralapproximation of the standard imset polytope is an LP relaxation of that polytope. In the end,we review recent attempts to apply the methods of integer programming to learning BN structuresand discuss the task of finding suitable explicit LP relaxation in the imset-based approach.
One example of general unidentifiable tensors
Authors: Chiantini Luca , Mella Massimiliano , Ottaviani Giorgio
Published: July 2015

The identiability of parameters in a probabilistic model is a crucial notion in statisticalinference. We prove that a general tensor of rank 8 in C3 C6 C6 has at least 6 decompositionsas sum of simple tensors, so it is not 8-identiable. This is the highest known example of balancedtensors of dimension 3, which are not k-identiable, when k is smaller than the generic rank.
A Family of Quasisymmetry Models
Authors: Kateri Maria , Mohammadi Fatemeh , Sturmfels Bernd
Published: July 2015

We present a one-parameter family of models for square contingency tables that interpolates between the classical quasisymmetry model and its Pearsonian analogue. Algebraically, this corresponds to deformations of toric ideals associated with graphs. Our discussion of the statistical issues centers around maximum likelihood estimation.
On the Connectivity of Fiber Graphs
Authors: Hemmecke Raymond , Windisch Tobias
Published: July 2015

We consider the connectivity of fiber graphs with respect to Gro ̈bner basis and Graver basis moves. First, we present a sequence of fiber graphs using moves from a Gro ̈bner basis and prove that their edge-connectivity is lowest possible and can have an arbitrarily large distance from the minimal degree. We then show that graph-theoretic properties of fiber graphs do not depend on the size of the right-hand side. This provides a counterexample to a conjecture of Engstro ̈m on the node-connectivity of fiber graphs. Our main result shows that the edge-connectivity in all fiber graphs of this counterexample is best possible if we use moves from Graver basis instead.
The precision space of interpolatory cubature formulæ
Authors: Fassino Claudia , Riccomagno Eva
Published: July 2015

Methods from Commutative Algebra and Numerical Analysis are combined to address a problem common to many disciplines: the estimation of the expected value of a polynomial of a random vector using a linear combination of a finite number of its values. In this work we remark on the error estimation in cubature formulæ for polynomial functions and introduce the notion of a precision space for a cubature rule.
The degeneration of the Grassmannian into a toric variety and the calculation of the eigenspaces of a torus action
Authors: Witaszek Jakub
Published: July 2015

Using the method of degenerating a Grassmannian into a toric variety, we calculate formulas for the dimensions of the eigenspaces of the action of an n-dimensional torus on a Grass- mannian of planes in an n-dimensional space.
FLACSO, CLACSO y la búsqueda de una sociología latinoamericana
Authors: Stavenhagen Rodolfo
Published: July 2015

El texto es un aporte personal de la memoria del autor vinculada a algunos momentos que vivió en relación con el desarrollo de la Facultad Latinoamericana de Ciencias Sociales (FLACSO) y del Consejo Latinoamericano de Ciencias Sociales (CLACSO). AbstractBased on his personal memories, the author reflects on significant moments in the creationand development of the Facultad Latinoamericana de Ciencias Sociales (FLACSO)and the Consejo Latinoamericano de Ciencias Sociales (CLACSO).
Diez años de apoyo a la Investigación Científica Básica por el CONACYT
Authors: Fabila Castillo Luis Humberto
Published: July 2015

En este trabajo se revisan los resultados de diez años de apoyo a la investigación científica básica del CONACYT. Se identifican las áreas del conocimiento más fuertes en ciencia básica en México y se concluye que las instituciones en donde se realiza ciencia básica son principalmente las instituciones de educación superior públicas, seguidas de los centros de investigación también públicos, mientras que las instituciones de educación superior privadas y las empresas casi no realizan investigación en ciencia básica. Se destaca que la ciencia básica tuvo un crecimiento muy grande en las universidades estatales, alcanzando en los últimos años el nivel de las instituciones de educación superior del Distrito Federal. Finalmente, se ponen a consideración las implicaciones de estos hallazgos y de las políticas con las que se han otorgado estos apoyos.AbstractThis paper reviews the results of ten years of support for basic scientific research by the CONACYT. The paper identifies the strongest areas of knowledge in basic science in Mexico and concludes that the institutions where basic science is done are mainly public higher education institutions, followed by also public research centers, while private institutions of higher education and companies carry out almost no research in basic science. Findings show that research on basic science in state universities has grown impressively in recent years, reaching the level of the institutions of higher education of the Federal District. Finally, the implications of these findings as well as the public policies through which support has been granted are discussed.
El Congreso peruano: políticas públicas e influencia informal sobre la burocracia
Authors: Patriau Enrique
Published: July 2015

Las reglas establecidas en la Constitución peruana dotan al Ejecutivo de herramientas que le permiten participar activamente en tareas legislativas. Al mismo tiempo, el Congreso es valorado como uno de los menos preparados -técnica y profesionalmente- de América Latina, con una incidencia mínima en la elaboración de políticas. Este trabajo plantea, sin embargo, que dicho análisis no toma en cuenta que la legislatura peruana participa en el proceso de políticas utilizando canales informales de influencia sobre la burocracia. Estos mecanismos se identifican a través de 31 entrevistas a profundidad a informantes claves: legisladores, funcionarios del Ejecutivo, funcionarios públicos de carrera y expertos en administración pública.AbstractThe Peruvian Constitution grants presidents the power to participate in the policy making process. At the same time, the Peruvian Congress is considered to lack the technical and professional ability to fully participate in such a process. However, such analysis neglects the influence that the Congress can exert through informal politics. Based on 31 interviews with legislators, political authorities, officials and experts in public administration this paper shows that the Peruvian legislature participates in the policy making process albeit through informal channels of influence over the bureaucracy.
Instrumentos de política pública para la conservación: su nacimiento y evolución en Colombia
Authors: Rodríguez R. Karla Juliana , Ávila Foucat V. Sophie
Published: July 2015

Se analiza el surgimiento y evolución de los únicos IEV que en el país se han diseñado para la conservación de los recursos naturales: la certificación forestal (CF) y el pago por servicios ambientales (PSA). Las entrevistas realizadas a actores clave muestran que en Colombia la fuerza de las tendencias internacionales promovió el surgimiento de dichos instrumentos. Sin embargo, aunque existen avances normativos y algunas experiencias en la implementación, la debilidad institucional genera que ninguno de los instrumentos logre avances suficientes para consolidarse como política pública nacional.AbstractIn this paper we analyze the emergence and evolution of two voluntary economic instruments for the conservation of natural resources in Colombia: forest certification (CF) and payment for environmental services (PES). Interviews with key actors show that international trends promoted the emergence of such instruments. However, although there is some normative progress and there are some experiences in implementation, institutional weakness generates none of the instruments to achieve sufficient progress to consolidate itself as a national public policy.
El ciclo confederativo: historia de la integración latinoamericana en el siglo XIX de Germán A. de la Reza
Authors: Brandi Aleixo José Carlos
Published: July 2015

Acceder al texto completo para consultar el contenido.
Experimental evidence that dispersal drives ant community assembly in human‐altered ecosystems
Authors: King Joshua R. , Tschinkel Walter R.
Published: July 2015

A key shortcoming in our understanding of exotic species’ success is that it is not known how post‐introduction dispersal contributes to the success of exotic species and the reassembly of invaded communities. Exotic and native species face poorly understood competition–colonization trade‐offs in heterogeneous landscapes of natural and anthropogenic habitats. We conducted three experiments that tested how ant queen behavior during dispersal affects community composition. Using experimental plots, we tested whether (1) different types of habitat disturbance and (2) different sizes of habitat disturbance affected the abundance of newly mated queens landing in the plots. The three most abundant species captured were the exotic fire ant Solenopsis invicta, and the native species Brachymyrmex depilis, and S. pergandei, respectively. When queens were considered collectively, more queens landed in plowed, sand‐added, and roadside plots than in control or mow plots, in other words, in the more heavily disturbed plots. We also tested (3) the effect of habitat manipulations on the survival of newly mated fire ant queens (Solenopsis invicta). Soil disturbance (tilling), lack of shade, and removal (poisoning) of the ant community resulted in the greatest fire ant colony survivorship. Collectively, experiments revealed that both exotic and native newly mated ant queens select open, human‐altered ecosystems for founding new colonies. The selection of such habitats by fire ant queens leads to their successful colony founding and ultimately to their dominance in those habitats. Selection of disturbed habitats is therefore advantageous for exotic species but is an ecological trap for native species because they do not often succeed in founding colonies in these habitats.
Efficacy of Human Chorion Membrane Allograft for Recession Coverage: A Case Series
Authors: Esteves Janice , Bhat K.M. , Thomas Betsy , Varghese Jothi M. , Jadhav Tanya
Published: July 2015

Background: Membranes of human placentas have been used in the field of medicine for skin grafts, treatment of burns, and ulcerated skin conditions with great success. The use of placenta allografts in dentistry is a more recent development, with the first commercial product being made available in 2008. The unique inherent biologic properties in placenta allografts enhance wound healing and may propagate regeneration.

Methods: Ten healthy adult patients presenting with 21 Miller Class I gingival recession (GR) defects (isolated or adjacent multiple) were surgically treated with a modified coronally advanced flap and chorion membrane for root coverage. Clinical parameters measured at baseline, 3 months, and 6 months were probing depth, clinical attachment level, GR height, width of keratinized gingiva, and assessment of gingival biotype. Statistical analysis was performed to compare the treatment outcomes at the follow‐up intervals.

Results: The results showed statistically significant (P <0.001) improvements in all clinical parameters at the 3‐ and 6‐month follow‐ups. The mean percentage of root coverage at the end of 6 months was 89.92% ± 15.59%, and 14 of 21 treated GR defects showed 100% root coverage. The gingival biotype also showed a thick biotype in nine sites that had an initial thin biotype.

Conclusions: Fetal membranes possess distinctive properties that can be harnessed to promote periodontal healing. The chorion membrane covered by a modified coronally advanced flap is a new approach that has shown promising results in terms of root coverage, increased width of keratinized tissue, and thickness of the gingival biotype.
Asphaltene Precipitation During Bitumen Extraction With Expanding-Solvent Steam-Assisted Gravity Drainage: Effects on Pore-Scale Displacement
Authors: Mukhametshina Albina , Kar Taniya , Hascakir Berna
Published: July 2015

Steam-assisted gravity drainage (SAGD) is a proved enhanced-oil-recovery technique for oil-sand extraction. However, the environmental and the economic challenges associated with steam generation limit the application of this technology. To address these issues, we have investigated the effectiveness of expanding-solvent-SAGD (ES-SAGD) over base SAGD on a bitumen sample (8.8 °API). Experimental studies are conducted with a 2D physical model. Different strategies for solvent injection are tested (coinjection and cyclic injection) to examine the impact of the deposition of the asphaltene fraction of the bitumen on porous media and the behavior of the asphaltene fraction in produced oil. Toluene is used as asphaltene-soluble solvent, and n-hexane is selected as asphaltene-insoluble. Steam-chamber development is monitored with temperature profiles from 47 separate positions. The oil rate, recovery factor, and the produced-oil quality are evaluated together. The effectiveness of SAGD and ES-SAGD is discussed by considering the role of asphaltenes and their interactions with clays in both produced- and residual-oil samples. This study reveals that coinjection of hydrocarbon solvents with steam enhances the steam-chamber development with higher oil-production rate. Moreover, ES-SAGD results in recovery of more-upgraded oil and has a lesser environmental impact. We observe that the selections of solvent type and injection strategy are the most crucial parameters for the design of a hybrid SAGD process, and solvent cost and toxicity can be minimized with the recycling of solvent for continuous injection of solvents. High-energy consumption for steam generation during the SAGD process can be reduced by coinjection of proper solvent type with steam at a proper injection strategy. Our study reveals that the ES-SAGD process has environmental and economic benefits that are preferable to those of the base SAGD. However, some solvents can cause undesirable effects because of asphaltene destabilization and precipitation in production or transportation lines. The results of this work show that not only asphaltenes but also the other fractions of oil, along with the reservoir-clay type and the clay amount, affect the ES-SAGD performance.
Perdido Development: Unified Fluid Model for Integrated-Production-System Modeling
Authors: Galvan D.. , McVinnie G.. , Dindoruk B..
Published: July 2015

The Perdido development is one of the most-complex deepwater projects in the world. It is operated by Shell in partnership with Chevron and BP. It currently produces hydrocarbons from 12 subsea wells penetrating four separate reservoirs. The properties of produced fluid vary per reservoir as well as spatially. The producing wells display a relatively wide range of fluid gravities, between 17 and 41 °API, and producing gas/oil ratios (GORs), between 480 and 3,000 scf/bbl. The fluids produced from the subsea wells are blended in the subsea system and lifted to the topside facilities by means of five seabed caisson electrical submersible pumps. In the topside facility, gas and oil are separated, treated, and exported by means of dedicated subsea pipelines. The fluid compositions and properties across the various elements of the production system are used as input data to the respective simulation models, and the corresponding outcomes (e.g., fluid properties, compositions) vary upon the well/caisson lineup and daily operating conditions.

Given the wide spectrum of fluids produced through the Perdido spar, a special equation-of-state (EOS) characterization of the fluids had to be developed. Because a common EOS model was used to characterize the fluids, we will call this the unified fluid model (UFM) throughout this study. This approach enables accurate and efficient prediction of the properties of blended fluids and is suitable for use in an integrated-production system model (IPSM) that connects reservoirs, wells, subsea-flowline networks, and topside-facilities models. Such a modeling scheme enables effective integration among relevant engineering disciplines and can represent production and fluid data from field history with high confidence.

The IPSM uses a black-oil fluid description for the well and subsea-flowline network models. By use of the initial composition and producing GOR of each well, the fluid composition is estimated by means of a simple delumping scheme. The resulting composition is tracked through the subsea network to the topside-facilities model, where compositional flash calculations are performed. The IPSM can forecast production rates together with fluid properties and actual oil- and gas-volumetric rates across the whole production system. The model can be used to optimize production under constrained conditions, such as limited gas-compression capacity or plateau oil production.
Risk of Dementia in Seniors With Newly Diagnosed Diabetes: A Population-Based Study
Authors: Haroon Nisha Nigil , Austin Peter C. , Shah Baiju R. , Wu Jianbao , Gill Sudeep S. , Booth Gillian L.
Published: July 2015

OBJECTIVE

To study whether diabetes onset in late life is a risk factor for dementia.

RESEARCH DESIGN AND METHODS

We conducted a population-based matched cohort study using provincial health data from Ontario, Canada. Seniors with (n = 225,045) and without newly diagnosed diabetes (n = 668,070) between April 1995 and March 2007 were followed until March 2012 for a new diagnosis of dementia. Cox proportional hazards modeling was used to compare the risk of dementia between groups after adjusting for baseline cardiovascular disease, chronic kidney disease (CKD), hypertension, and other risk factors.

RESULTS

Over this period, we observed 169,114 new cases of dementia. Individuals with diabetes had a modestly higher incidence of dementia (2.68 vs. 2.62 per 100 person-years) than those without diabetes. In the fully adjusted Cox model, the risk of dementia was 16% higher among our subgroup with diabetes (hazard ratio [HR] 1.16 [95% CI 1.15–1.18]). Adjusted HRs for dementia were 1.20 (95% CI 1.17–1.22) and 1.14 (95% CI 1.12–1.16) among men and women, respectively. Among seniors with diabetes, the risk of dementia was greatest in those with prior cerebrovascular disease (HR 2.03; 95% CI 1.88–2.19), peripheral vascular disease (HR 1.47; 95% CI 1.19–1.82), and CKD (HR 1.44; 95% CI 1.38–1.51), and those with one or more hospital visits for hypoglycemia (HR 1.73; 95% CI 1.62–1.84).

CONCLUSIONS

In this population-based study, newly diagnosed diabetes was associated with a 16% increase in the risk of dementia among seniors. Preexisting vascular disease and severe hypoglycemia were the greatest risk factors for dementia in seniors with diabetes.
Type 1 Diabetes Is Associated With an Increased Risk of Fracture Across the Life Span: A Population-Based Cohort Study Using The Health Improvement Network (THIN)
Authors: Weber David R. , Haynes Kevin , Leonard Mary B. , Willi Steven M. , Denburg Michelle R.
Published: July 2015

OBJECTIVE

This study was conducted to determine if type 1 diabetes is associated with an increased risk of fracture across the life span.

RESEARCH DESIGN AND METHODS

This population-based cohort study used data from The Health Improvement Network (THIN) in the U.K. (data from 1994 to 2012), in which 30,394 participants aged 0–89 years with type 1 diabetes were compared with 303,872 randomly selected age-, sex-, and practice-matched participants without diabetes. Cox regression analysis was used to determine hazard ratios (HRs) for incident fracture in participants with type 1 diabetes.

RESULTS

A total of 334,266 participants, median age 34 years, were monitored for 1.9 million person-years. HR were lowest in males and females age <20 years, with HR 1.14 (95% CI 1.01–1.29) and 1.35 (95% CI 1.12–1.63), respectively. Risk was highest in men 60–69 years (HR 2.18 [95% CI 1.79–2.65]), and in women 40–49 years (HR 2.03 [95% CI 1.73–2.39]). Lower extremity fractures comprised a higher proportion of incident fractures in participants with versus those without type 1 diabetes (31.1% vs. 25.1% in males, 39.3% vs. 32% in females; P < 0.001). Secondary analyses for incident hip fractures identified the highest HR of 5.64 (95% CI 3.55–8.97) in men 60–69 years and the highest HR of 5.63 (95% CI 2.25–14.11) in women 30–39 years.

CONCLUSIONS

Type 1 diabetes was associated with increased risk of incident fracture that began in childhood and extended across the life span. Participants with type 1 diabetes sustained a disproportionately greater number of lower extremity fractures. These findings have important public health implications, given the increasing prevalence of type 1 diabetes and the morbidity and mortality associated with hip fractures.
Continuous versus pulsed origination and extinction and biozones
Authors: Trammer Jerzy
Published: July 2015

The count of biozones as an approximate measure of the origination and extinction rates of index taxa (mostly species) is proposed. The mean number of extinctions of these taxa per m.y. is 1.136 (Palaeozoic mean 0.902, Mesozoic mean 1.680, Cenozoic mean 0.789). In contrast with the majority of taxa, the originations and extinctions of index taxa, as well as of other taxa belonging to biostratigraphically important systematic groups, seems to be continuous.
Regional hardening of Upper Cretaceous Chalk in eastern England, UK: trace element and stable isotope patterns in the Upper Cenomanian and Turonian Chalk and their significance
Authors: Jeans Christopher V. , Long Dee , Hu Xiu-Fang , Mortimore Rory N.
Published: July 2015

The regional hardening of the Late Cenomanian to Early Turonian Chalk of the Northern Province of eastern England has been investigated by examining the pattern of trace elements and stable carbon and oxygen isotopes in the bulk calcite of two extensive and stratigraphically adjacent units each 4 to 5 m thick of hard chalk in Lincolnshire and Yorkshire. These units are separated by a sequence, 0.3-1.3 m thick, of variegated marls and clayey marls. Modelling of the geochemistry of the hard chalk by comparison with the Standard Louth Chalk, combined with associated petrographic and geological evidence, indicates that (1) the hardening is due to the precipitation of a calcite cement, and (2) the regional and stratigraphical patterns of geochemical variation in the cement are largely independent of each other and have been maintained by the impermeable nature of the thin sequence of the clay-rich marls that separate them. Two phases of calcite cementation are recognised. The first phase was microbially influenced and did not lithify the chalk. It took place predominantly in oxic and suboxic conditions under considerable overpressure in which the Chalk pore fluids circulated within the units, driven by variations in compaction, temperature, pore fluid pressure and local tectonics. There is evidence in central and southern Lincolnshire of the loss of Sr and Mgenriched pore fluids to the south during an early part of this phase. The second phase of calcite precipitation was associated with the loss of overpressure in probably Late Cretaceous and in Cenozoic times as the result of fault movement in the basement penetrating the overlying Chalk and damaging the seal between the two chalk units. This greatly enhanced grain pressures, resulting in grain welding and pressure dissolution, causing lithification with the development of stylolites, marl seams, and brittle fractures. Associated with this loss of overpressure was the penetration of the chalk units by allochthonous fluids, rich in sulphate and hydrocarbons, derived probably from the North Sea Basin. Microbial sulphate-reduction under anoxic conditions within these allochthonous fluids has been responsible for dissolving the fine-grained iron and manganese oxides within the chalk, locally enriching the Fe and Mn content of the calcite cement. The possibility is discussed that the pattern of cementation preserved in these regionally hard chalks of Late Cenomanian and Early Turonian age may be different from that preserved in the younger (late Turonian to Campanian) more basinal chalks of eastern England.
U-total Pb timing constraints on the emplacement of the granitoid pluton of Stolpen, Germany
Authors: Lisowiec Katarzyna , Budzyń Bartosz , Słaby Ewa , Schulz Bernhard , Renno Axel D.
Published: July 2015

Monazite from the Stolpen monzogranite (SE Germany) was studied to constrain the Th-U-total Pb age of pluton formation. Monazite grains demonstrate subtle to distinct patchy zoning related to slight compositional variations. Textural and compositional characteristics indicate that the monazite formed in a single magmatic event in a slightly heterogeneous system, and was only weakly affected by secondary alteration, which did not disturb the Th-U-Pb system. Chemical dating of the monazite gave a consistent age of 299 ± 1.7 Ma. The current study presents the first geochronological data for the Stolpen granite. It provides evidence that Stolpen is the youngest Variscan granitic intrusion in the Lusatian Granodiorite Complex and indicates that magmatic activity related to post-collisional extension in this region lasted at least 5my longer than previously assumed
Predictive Significance of Tissue Eosinophilia for Nasal Polyp Recurrence in the Chinese Population
Authors: Lou Hongfei , Meng Yifan , Piao Yingshi , Wang Chengshuo , Zhang Luo , Bachert Claus
Published: July 2015

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) remains a challenging clinical entity with its propensity for recurrence. Tissue eosinophilia is a hallmark of CRSwNP, and its role in polyp recurrence is a subject of much investigation.

Objective

The aim of this study was to evaluate the association between clinical parameters, especially tissue eosinophilia and polyp recurrence, and to identify the optimal cutoff value of tissue eosinophilia as a predictor for polyp recurrence in Chinese subjects.

Methods

Overall, 387 patients with CRSwNP were enrolled in this retrospective analysis and postoperative follow-up for polyp recurrence was over a period that lasted >24 months (mean [standard deviation], 34.03 ± 4.95 months). The baseline demographic and clinical features and the preoperative computed tomography were compared, and mucosal specimens obtained at endoscopic sinus surgery were assessed for inflammatory cells by using histocytologic staining. Predictive factors associated with polyp recurrence were analyzed by logistic regression analysis, and optimal cutoff points of the predictors were determined by receiver operating characteristic curves and the Youden index.

Results

A total of 55.3% patients (214β87) experienced recurrence. Tissue eosinophilia markedly outweighed other parameters and correlated with polyp recurrence. Receiver operating characteristic curves indicated that a cutoff value of 27% tissue eosinophils predicted recurrence with 96.7% sensitivity and 92.5% specificity (area under the curve = 0.969; p < 0.001); and an absolute count of 55 eosinophils per high power field predicted recurrence with 87.4% sensitivity and 97.1% specificity (area under the curve = 0.969; p < 0.001).

Conclusion

A tissue eosinophil proportion of >27% of total cells or a tissue eosinophil absolute count of >55 eosinophils per high power field may act as a reliable prognostic indicator for nasal polyp recurrence within 2 years after surgery.
Reconstruction of Lahti station area, demands of the new fast speed railroad between Helsinki and Lahti
Authors: Vilonen Ilkka
Published: July 2015

In this paper, a rehabilitation project of Lahti railroad station is described. The aim of this project was to improve the structure of Lahti rail-yard to meet the challenges of the new fast speed railroad between Kerava and Lahti. Tracks locations were changed and the rail-yard had to widen south 17 meters. These Changes demanded to demolish old pedestrian bridge, rebuild the piers, elevators, stairs and platform-roofs too. All works had to make so, that rail traffic was able to use at least three parallel tracks whole time on Lahti station.
Long-term monitoring of Haavistonjoki Bridge
Authors: Laaksonen Anssi , Kerokoski Olli
Published: July 2015

Integral and semi-integral bridge expansion due to temperature changes is not symmetrical measured from the bridge's centre point. The movements are strongly influenced by the nonlinear behaviour of the embankment soil. Due to different embankment stiffnesses, the western abutment was much stiffer than the eastern one, and occasionally the expansion length of the 50 m long symmetrical bridge exceeded 35 metres. The bearing movements of a semi-integral bridge can be predicted based on the presented integral bridge's monitoring results.

In the presented field study the focus was on the reversible and non-reversible earth pressure actions caused by an integral bridge. The changes in earth pressure were the result of bridge abutment movements due to bridge deck temperature changes. According to the observations made, it is possible to determine which actions are the result of bridge abutment movements.

Deck temperature changes either expand or contract the deck which, again, affects the earth pressures behind abutments. The highest average deck temperature during the two-year observation period was 30.4 °C, the lowest was –14.9 °C, and the average 7.7 °C. At the edges and top, measured deck temperatures corresponded most closely to air temperature changes. At the bottom deck temperatures also followed air temperature changes, but more slowly. The smallest temperature changes were measured in the middle of the deck.
Design of infrastructure incorporating monitoring regimes to evaluate the
performance and schedule maintenance over the entire life time
Authors: Siegwart Michael , Zwicky P.
Published: July 2015

Bridges are generally designed for a life time of 120 years. The structural behaviour and material
degradation mechanisms are considered during the design stage in order to achieve this design life.
The life time of the structure, which is subject to a variety of loads and exposed to certain
environmental conditions, depends therefore to a large extent on the assumptions made during the
design stage. However, experience has shown that especially loading conditions i.e. traffic loading
is likely to deviate from the assumptions made during the design stage. Further, the impact of
exceptional events such as earthquakes could affect the integrity of the structure. The degradation of
a structure very often has not progressed very far and when the structure is monitored, it is possible
to extend maintenance free periods. Further, with monitoring hard- and software becoming more
and more sophisticated, it is possible to have this information readily available any time. Therefore,
it is recommended that monitoring regimes are considered as an integral part of the design and
become part of the maintenance schedule of any major infrastructure project. In short, monitoring
regimes can be used to optimise spending on maintenance. In this paper, one possible use of
structural monitoring is shown on the example of the bridge over the river Reuss in Wassen,
Switzerland. The cost of the monitoring regime is compared to the cost savings made by it over the
lifetime of the project. In addition, the design criteria of such a system required to achieve a
permanent monitoring throughout the lifetime of a structure are explained and the use of the data
for a bridge maintenance strategy is shown. Monitoring regimes can be used as a maintenance tool
to optimise spending over the life time of the object and, ultimately, to safe costs.
Inspection and risks of hidden defects
Authors: Tilly Graham
Published: July 2015

Inspection of structures is usually a straight forward and routine activity mainly concerned with serviceability issues but on occasions it can present problems. These problems arise when critical defects are hidden from view and if left to develop can lead to collapse of the structure without warning. In practice there have been a number of occasions when bridges have collapsed soon after an inspection which had shown that there were apparently no serious defects.

Three very different examples having hidden defects are described and discussed. These involve a cast iron beam, a post-tensioned concrete deck and holding down bolts on a steel viaduct.
Behavior of partially earth anchored cable-stayed bridge considering construction phase and operational phase
Authors: Kim Sang-Hyo , Kwang-Il C. , Cho K.-I. , Jin-Hee A. , Ahn J.-H.
Published: July 2015

In this study, the behavior of a cable-stayed bridge with a partially earth anchored cable system was studied both for the construction phase and for the operational phase. The recently constructed 3- span cable-stayed bridge with a usual self anchored cable system in Korea was modified into a partially earth anchored cable system. According to the FCM construction method, the construction sequence analysis was performed to find optimal cable stressing forces. Effects of the systems with partially earth anchored cables were examined by comparing the self anchored cable system.

The behavior of the partially earth anchored cable-stayed bridge in the operational phase was investigated. The live load analysis was carried out according to the Korean vehicle class. Also, the response spectrum analysis for the seismic load and the buffeting analysis for the wind dynamic load were carried out. From these results, it is shown that the partially earth anchored cable-stayed bridge increases the resistant capacity against the service loads.
Sensitivity-based Optimal Design of Linear Damper System for Enhanced Seismic Performance of Coupled Structural System
Authors: Kim Dong-Seok , Koh Hyun-Moo , Ok Seung-Yong , Park Kwan-Soon , Choi Chang-Yeol
Published: July 2015

This paper describes a sensitivity-based optimal design method of linear damper system for connected structures. In order to determine the optimal distribution of the linear dampers, a measure based on the sensitivity of target modal damping ratio to damper distribution is introduced. In order to demonstrate the effectiveness of the proposed method, two numerical examples of seismically excited coupled systems are considered; the first one is for the adjacent buildings interconnected with dampers, and the second is for the parallel bridges transversely connected with dampers. The simulated results show that the sensitivity-based optimal damping system can save the damper cost more efficiently than the uniformly distributed optimal damping system without any loss of seismic performance of the coupled structures.
Reliability and progressive collapse of structures
Authors: de Boer Ane , van der Veen Cornelis
Published: July 2015

The number of incidents of progressive collapse of structures has increased over the last decade. Design faults are becoming more frequent and the simple collapse of a structure during construction or in exploitation has become commonplace during the lifetime of a structure. Before the permit is granted to start the construction phase, the design has to be checked. In many European countries the technical review has been changed into a purely administrative process. The technical side of this process has become a process, which is covered by certified partners. The technical side seems to have become an administrative process not only during this permit phase of the structure but also during the construction phase of the structure. Meanwhile, the recent collapse of large halls and shops in Europe has changed the design thinking of engineers. A discussion is in progress and will lead to an acceptable solution for these processes. This discussion will probably lead to new rules or regulations and possibly new engineering schemes. The merging of different types of existing tools can minimise the number of new rules and regulations. In order to keep innovations on the agenda in the near future, the engineer must be free to design the structures of tomorrow.
Form as a result of local conditions. Architectural design of two new urban bridges in San Sebastian. Spain.
Authors: Capellán Guillermo , Guerra Santiago , Merino Emilio , Sacristán Miguel
Published: July 2015

This paper introduces two singular structures designed in the city of San Sebastian. The singularity of these bridges is based not on its dimensions or technical features, but in the way they adapt its design to local conditions. The 6th bridge over the Urumea River will be finished in 2010. This skewed urban bridge is 90 m long, with three spans of approx. 30 m, and 22 m wide. The bridge replaces an existing steel structure with historical values which is reused as a footbridge in a green area. It crosses the river parallel to the existing railway bridge, with associated visual and noise disturbances for the area. The new bridge in the area of Txomin-Enea over the Urumea River adapts to the different characteristics of the river banks. As the left bank will be a newly urbanized area with a green park following the river with walking and cycling paths. The structure uses two spans of 42 and 18 m, with the main span over the river and the side span over the new green area.
Visual Impact Assessment for Infrastructure Design
Authors: Lamberti Renato , Russo Francesca , Dell'Acqua Gianluca
Published: July 2015

The following paper illustrates the verification of methodologies employed by international agencies to assess theScenic Qualityof a landscape. Several States determine a landscape’svisual qualityusing predictor variables. This research aims to validate the recognized ability of these predictor variables to reproduce untrained observers’ preferences. Three variables have been chosen to analyze a series of Italian landscapes:Vividness,IntactnessandUnity. Photographic inventories were created for different landscapes. Pools of landscape architects judged the slides associated to each landscape using a 7-point scale. Identical slides were then shown to untrained observers composed of 201 students that used a 10-point scale to evaluateScenic Beautyfor each picture. Students’ judgments were then related to the expert judgments using a regression analysis. Road evaluation from the landscape will be a future application using simulation or rendering techniques.
Geodetic Domes for great-span structures: Mandela Forum Project proposal in Florence
Authors: Armeni Giulia , Borri Claudio , De Bartolomeis Paolo , Di Naso Vincenzo , Orlando Maurizio
Published: July 2015

The paper concerns the design of a new sports arena and in particular of a aluminium roof structure for the Mandela Forum, which is the major sports arena of Florence. The project key-element is the aluminium geodesic dome, chosen in order to set up a covering with optimal and functional structure and shape. The key topic discussed in this paper concerns the geometrical issue of the structural optimization, in fact comparing several types of iron framework domes, the geodesic one seemed to be the best choice, as proved through mathematical and computational models. The numerical analyses showed that the geodesic framework is stiffer than other configurations, moreover it minimizes the material used: indeed the overall beam length is optimized. Furthermore, due to the framework regularity, the stress state is almost uniform in the whole structure beams.
Rehabilitation of an industrial building in three different solutions
Authors: Chira Nicolae , Campian Cristina
Published: July 2015

This paper presents a case study of single-storey steel buildings imported from another country. The frame was analyzed to meet the specific requirements of the Romanian design codes and results show that the structure requires retrofitting. Three cases are suggested, each of the three cases are analyzed and subjected to some concluding remarks.
Planning and Design of Elevated Road for Aizawl City
Authors: Kapoor Rakesh
Published: July 2015

Rakesh Kapoor, born 1958, received his civil engineering degree from Delhi University, India. He worked for Consultants Companies in Delhi. His main area of experience is design of bridges and flyovers.

An elevated road of 2.25Km is to be constructed over an arterial road in Aizawl city on hilly terrain passing through built up urban areas. Proposed viaduct has complicated geometry with closely spaced curves and variable grades. Constructing the viaduct on existing two-lane road in running traffic in a phased manner is the project challenge. Design has to complement the scheme of construction.