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This paper is devoted to the experimental and numerical assessment of residual stresses created by welding in the region surrounding the weld toe of tubular K-shaped joints (i.e. region most sensitive to fatigue cracking). Neutron-diffraction measurements were carried out on K-joints cut from large-scale truss beams previously subjected to high cycle fatigue. Tri-axial residual stresses in the transverse, longitudinal and radial direction were obtained from the weld toe as a function of the depth in the thickness of the tube wall. In addition, thermomechanical analyses were performed in three-dimensional using ABAQUS and MORFEO finite element codes. Experimental and numerical results show that, at and near the weld-toe surface, the highest residual stresses are critically oriented perpendicularly to the weld direction, and combined with the highest externally applied stresses. Based on a systematic study on geometric parameters, analytical residual stress distribution equations with depth are proposed.

The material UHPFRC is not yet used in the field of bridge construction regularly. The reasons are missing codes and allurements for innovation in the structural engineering. Nevertheless, UHPFRC has many advantages, which are significant compared to the use of concrete in this case: the replacement of a railway bridge. This paper documents two tests of reinforced UHPFRC beams. This tests has been done in the context of the validation of the dimensioning: one bending test and one shear forcer test. Furthermore, the reasons for the choice, the specimen geometry as well as the test results are presented. Finally, the investigated load bearing capacities will be compared with analytical models.

Search engines essentially rely on the structure of the graph of hyperlinks. Although accurate for the main trend, this is not effective when some query is ambiguous. Leveraging semantic information by the mean of interest matching allows proposing complementary results that are tailored to the user's expectations. This paper proposes a collaborative search companion system, CoFeed, that collects user search queries and that considers feedback to build user-centric and document-centric profiling information. Over time, the system constructs ranked collections of elements that maintain the required information diversity and enhance the user search experience by presenting additional results tailored to the user's interest space. This collaborative search companion requires a supporting architecture adapted to large user populations generating high request loads. To that end, it integrates mechanisms for ensuring scalability and load balancing of the service under varying loads and user interest distributions. Moreover, collecting the recommendation data poses the problem of users' privacy, and the bias one peer can induce to the system by sending fake recommendations. To that end, CoFeed ensures both publisher anonymity and rate limitation. With the former, the origin of the data is never known by the server that processes it, even if several servers collude to spy on some user. The latter, combined with decoupled authentication, allows to minimize the influence of cheating peers sending fake recommendations. Experiments with a deployed prototype highlight the efficiency of the system by analyzing improvement in search relevance, computational cost, scalability and load balancing. Copyright (c) 2011 John Wiley & Sons, Ltd.

SUMMARY: This paper investigates the effect of the composite action on the seismic performance of steel special moment frames (SMFs) through collapse. A rational approach is first proposed to model the hysteretic behavior of fully restrained composite beam-to-column connections, with reduced beam sections. Using the proposed modeling recommendations, a system-level analytical study is performed on archetype steel buildings that utilize perimeter steel SMFs, with different heights, designed in the West-Coast of the USA. It is shown that in average, the composite action may enhance the seismic performance of steel SMFs. However, bottom story collapse mechanisms may be triggered leading to rapid deterioration of the global strength of steel SMFs. Because of composite action, excessive panel zone shear distortion is also observed in interior joints of steel SMFs designed with strong-column/weak-beam ratios larger than 1.0. It is demonstrated that when steel SMFs are designed with strong-column/weak-beam ratios larger than 1.5, (i) bottom story collapse mechanisms are typically avoided; (ii) a tolerable probability of collapse is achieved in a return period of 50years; and (iii) controlled panel zone yielding is achieved while reducing the required number of welded doubler plates in interior beam-to-column joints. © 2014 John Wiley & Sons, Ltd.

We have synthesized a 17-mer peptide (ER17p) that is issued from the hinge region of the estrogen receptor and which activates the proliferation of breast carcinoma cells in steroid-deprived conditions. In the present paper, we show that at a concentration of similar to 50M, it rapidly forms amyloid-like fibrils with the assistance of electrostatic interactions and that at higher concentrations, it spontaneously forms a hydrogel. By using biophysical, spectral and rheological techniques, we have explored the structural, biophysical and mechanical characteristics of ER17p with respect to fibril formation and gelation. Copyright (c) 2014 European Peptide Society and John Wiley & Sons, Ltd.

Understanding the genetic basis of species adaptation in the context of global change poses one of the greatest challenges of this century. Although we have begun to understand the molecular basis of adaptation in those species for which whole genome sequences are available, the molecular basis of adaptation is still poorly understood for most non-model species. In this paper, we outline major challenges and future research directions for correlating environmental factors with molecular markers to identify adaptive genetic variation, and point to research gaps in the application of landscape genetics to real-world problems arising from global change, such as the ability of organisms to adapt over rapid time scales. High throughput sequencing generates vast quantities of molecular data to address the challenge of studying adaptive genetic variation in non-model species. Here we suggest that improvements in the sampling design should consider spatial dependence among sampled individuals. Then, we describe available statistical approaches for integrating spatial dependence into landscape analyses of adaptive genetic variation.

This paper discusses an analytical study that quantifies the expected earthquake-induced losses in typical office steel frame buildings designed with perimeter special moment frames in highly seismic regions. It is shown that for seismic events associated with low probabilities of occurrence, losses due to demolition and collapse may be significantly overestimated when the expected loss computations are based on analytical models that ignore the composite beam effects and the interior gravity framing system of a steel frame building. For frequently occurring seismic events building losses are dominated by non-structural content repairs. In this case, the choice of the analytical model representation of the steel frame building becomes less important. Losses due to demolition and collapse in steel frame buildings with special moment frames designed with strong-column/weak-beam ratio larger than 2.0 are reduced by a factor of two compared with those in the same frames designed with a strong-column/weak-beam ratio larger than 1.0 as recommended in ANSI/AISC-341-10. The expected annual losses (EALs) of steel frame buildings with SMFs vary from 0.38% to 0.74% over the building life expectancy. The EALs are dominated by repairs of acceleration-sensitive non-structural content followed by repairs of drift-sensitive non-structural components. It is found that the effect of strong-column/weak-beam ratio on EALs is negligible. This is not the case when the present value of life-cycle costs is selected as a loss-metric. It is advisable to employ a combination of loss-metrics to assess the earthquake-induced losses in steel frame buildings with special moment frames depending on the seismic performance level of interest.

Aim: In this paper, we link historical land use of cultivated parcels formerly slashed and burnt, with current secondary vegetation and soil characteristics, in the region of evergreen rain forest in Madagascar. Aim is to understand the legacy effect of former cultivation practices in order to optimize slash-and-burn cultivation. Location: Forest corridor of Fianarantsoa, southeast Madagascar. Methods: We examined three study sites to capture the ecological range in the forest corridor of Fianarantsoa. At each site, we selected formerly hand-cultivated parcels since first forest clearing so as to represent up to four classes of age of abandonment, encompassing forest fallow periods after cultivation of 0-5, 6-10, 11-20 and 21-30 yrs. These parcels served for selection of 50 plots. Interviews were conducted with each farmer to document former cultivation practices of the parcels, and from these, land-use metrics were calculated. Vegetation was surveyed in the plots and soil samples were taken and analysed for chemical and physical properties of the organo-mineral layer (horizon A). Results: We found that soil properties, such as pH, have higher values with an increasing number of cultivation cycles and duration of cultivation, and that this trend is inversely related to exchangeable P. C/N ratio is correlated to age of abandonment, and inversely related to soil N content. With increasing age of abandonment, species richness and diversity increase due mainly to an increase in ligneous species. The number of herbaceous and fern species increases with duration of cultivation and number of cultivation cycles. Conclusion: Historical land use has had a lasting effect on vegetation and even longer-term effect on soils. Different land-use variables explain soil and vegetation characteristics of the current secondary forest. The ability of soils to recover P appears unrelated to abandonment duration, suggesting that longer periods of time are required to recover P fertility, or that secondary vegetation is shifting the pool of nutrients into biomass. Our results point to the need for a management regime that would maintain both scattered trees and patches of a grass layer, since this might be key to promoting both biodiversity and soil restoration.

1. Ongoing environmental change is predicted to have a strong impact on biodiversity. Studies have already noted a range shift in many species as they track their favoured environments. A key challenge entomologists are facing is to understand how insect pest species are responding to this rapid environmental change, and molecular ecology has a central role to play in this task. In the present paper, I argue that molecular ecology has much relevance in relation to the monitoring of insect pests of agricultural importance, with a focus on aphids. 2. First, I examine how the combination of phylogeography and species distribution modelling can be a powerful approach to understanding species responses to climate change and to forecasting future distributions. Despite such a joint approach being increasingly used to understand these questions (e.g. in conservation biology), there are still very few studies that concern pest species of agricultural importance. 3. I then discuss how the use of samples from natural history collections represent an opportunity to directly observe the evolution of species, enhancing our knowledge of the evolutionary processes occurring at ecological time scales. I introduce the Rothamsted Insect Survey (RIS) sample archive and the central role it plays in the studies of pest species of agricultural importance. 4. Lastly, I assess how the advances in DNA sequencing technologies have allowed us to investigate genetic variation at the genome-wide level. Thus, they provide us with the opportunity of studying a variety of questions about the dynamics of pest insects that were previously impossible as well as unmanageable.

This paper reports on a study analysing the spatial distribution functions, the correlation structures, and the power spectral densities of high-resolution LIDAR snow depths (∼1 m) in two adjacent 500 m × 500 m areas in the Colorado Rocky Mountains, one a sub-alpine forest the other an alpine tundra. It is shown how and why differences in the controlling physical processes induced by variations in vegetation cover and wind patterns lead to the observed differences in spatial organization between the snow depth fields of these environments. In the sub-alpine forest area, the mean of snow depth increases with elevation, while its standard deviation remains uniform. In the tundra subarea, the mean of snow depth decreases with elevation, while its standard deviation varies over a wide range. The two-dimensional correlations of snow depth in the forested area indicate little spatial memory and isotropic conditions, while in the tundra they indicate a marked directional bias that is consistent with the predominant wind directions and the location of topographic ridges and depressions. The power spectral densities exhibit a power law behaviour in two frequency intervals separated by a break located at a scale of around 12 m in the forested subarea, and 65 m in the tundra subarea. The spectral exponents obtained indicate that the snow depth fields are highly variable over scales larger than the scale break, while highly correlated below. Based on the observations and on synthetic snow depth fields generated with one- and two-dimensional spectral techniques, it is shown that the scale at which the break occurs increases with the separation distance between snow depth maxima. In addition, the breaks in the forested area coincide with those of the corresponding vegetation height field, while in the tundra subarea they are displaced towards larger scales than those observed in the corresponding vegetation height field.

In this paper, we are interested in the spatio-temporal dynamics of the transmembrane potential in paced isotropic and anisotropic cardiac tissues. In particular, we observe a specific precursor of cardiac arrhythmias that is the presence of alternans in the action potential duration. The underlying mathematical model consists of a reaction–diffusion system describing the propagation of the electric potential and the nonlinear interaction with ionic gating variables. Either conforming piecewise continuous finite elements or a finite volume-element scheme are employed for the spatial discretization of all fields, whereas operator splitting strategies of first and second order are used for the time integration. We also describe an efficient mechanism to compute pseudo-ECG signals, and we analyze restitution curves and alternans patterns for physiological and pathological cardiac rhythms.

As environmental awareness grows, firms are expected to expand the scope of their environmental strategies beyond organisational boundaries and to address more comprehensively environmental issues in their supply chains and product life cycles. Drawing on different literature streams, international standards and corporate disclosure, this paper presents a conceptual framework for the quantitative assessment of the comprehensiveness of firms' environmental strategies. This framework allows us to capture: (i) the environmental inputs and outputs addressed, (ii) the firm versus supply chain orientation of environmental strategies, and (iii) the environmental management practices adopted by companies. We illustrate the application of this framework with a content analysis of corporate sustainability reports for a cross-sectoral sample of sustainability leaders. Our results indicate that there is a need for greater specificity in environmental reporting and that, overall, companies remain firm-oriented. It is also observed that supply chain orientation can generally be associated with stakeholder pressure. Copyright (c) 2012 John Wiley & Sons, Ltd and ERP Environment.

Discharge simulation from snow-dominated catchments seems to be an easy task. Any spatially explicit precipitation–runoff model coupled to a temperature-index snow model generally yields simulations that mimic well the observed daily discharges. The robustness of such models is, however, questionable: in the presence of strong annual discharge cycles, small model residuals do not guarantee high explanatory power of the underlying model. This paper proposes a methodology for snow hydrological model identification within a limits-of-acceptability framework, where acceptable model simulations are the ones that reproduce a set of signatures within an a priori specified range. The signatures proposed here namely include the relationship between the air temperature regime and the discharge regime, a new snow hydrology signature that can be readily transferred to other Alpine settings. The discriminatory power of all analysed signatures is assessed with a new measure of their discriminatory power in the model prediction domain. The value of the proposed snow hydrology signatures and of the limits-of-acceptability approach is demonstrated for the Dischma river in Switzerland, whose discharge shows a strong temporal variability of hydrologic forcing conditions over the last 30 years. The signature-based model identification for this case study leads to the surprising conclusion that the observed discharge data contains a multi-year period that cannot be reproduced with the model at hand. This model-data mismatch might well result from a yet to be identified problem with the discharge observations, which would have been difficult to detect in a classical residual-based model identification approach. Overall, the detailed results for this case study underline the robustness of the limits-of-acceptability approach in the presence of error-prone observations if it is applied in combination with relatively robust signatures. Future work will show whether snow hydrology signatures and their limits-of-acceptability can be regionalized to ungauged catchments, which would make this model selection approach particularly powerful for Alpine environments. Copyright © 2016 John Wiley & Sons, Ltd.

Riparian vegetation influences hydraulic and morphodynamic river processes and may contribute to sediment stabilization. In turn, vegetation recruitment and growth on non-cohesive fluvial deposits strongly depends on river hydrology and the ability of roots to develop and to anchor efficiently to resist flow erosion. In this paper, we examine the above-ground and the below-ground seasonal growth dynamics of Salix cuttings in relation to local river hydrodynamics and morphodynamics, on the basis of a detailed and unique data set. During the two season-long campaigns in 2009 and 2010, 1188 and 1152 cuttings, respectively, were organized in square plots and planted on a gravel island of the restored reach of the River Thur (Neunforn, Thurgau, Switzerland). Each year, all cuttings were monitored almost regularly from the beginning until the end of the growing season (April-September). Root development statistics were also obtained from high-resolution scanner analysis of carefully uprooted samples from selected plots. Our results show how cutting survival and the nature and strength of correlations between island topography and cutting growth statistics depend on river hydrology. An empirical functional form that links root development based on the measured main stem length is then proposed for predictive purposes. Cutting mortality following flood events is shown to depend nonlinearly on both erosion and deposition processes, whereas it appears more linearly related to the magnitude of the bed shear stress distribution generated by the maximum seasonal flood. This analysis allows an identification of an important threshold for plant survival within different erosion and deposition regimes, which explains the spatial and temporal distribution of the surviving cuttings within the plots. These results have practical implications, for instance, for evaluating, planning and managing the use of riparian trees in restoration projects. Copyright (c) 2013 John Wiley & Sons, Ltd.

At the mesoscopic scale, concrete can be considered as a mix of coarse aggregates with a mortar paste matrix. In this paper, we investigate numerically the influence of aggregates arrangements and loading rate on the tensile response of concrete. Each coarse aggregate is assumed to be circular with six different radiuses following the aggregates size distribution of real gravel. Rate-independent cohesive elements are used to model failure within the mesostructure. Our results show that the spatial distribution of heterogeneities does not influence the peak strength, while it changes the post-peak macroscopic response. This implies that our specimen size is large enough for strength computation but that larger mesostructures should be considered to obtain fully reliable toughness predictions. Although the cohesive approach is able to capture the transition from one macro-crack in quasi-static to multiple micro-cracks in fast dynamics, which increases the dissipated fracture energy, our results suggest that the full extent of the high-rate strengthening of concrete observed experimentally for loading rates greater than math formula epsilon = 1/s cannot be captured with rate independent constitutive laws.

The paper introduces a functional time series (lagged) regression model. The impulse-response coefficients in such a model are operators acting on a separable Hilbert space, which is the function space L-2 in applications. A spectral approach to the estimation of these coefficients is proposed and asymptotically justified under a general nonparametric condition on the temporal dependence of the input series. Since the data are infinite-dimensional, the estimation involves a spectral-domain dimension-reduction technique. Consistency of the estimators is established under general data-dependent assumptions on the rate of the dimension-reduction parameter. Their finite-sample performance is evaluated by a simulation study that compares two ad hoc approaches to dimension reduction with an alternative, asymptotically justified method.