In construction projects, resource availability might limit the implementation of ideal schedules. Especially, when repetitive activities are involved, traditional resource‐constrained project ...scheduling problem (RCPSP) models fail to allocate the resource consumption in an efficient manner. Besides, actual models only provide local optimal solutions and do not incorporate activity acceleration routines. To fulfill this gap, partially, a mathematical optimization model, the multimode RCPSP for repetitive activities in construction projects, is proposed and solved to optimality; it takes into account acceleration routines under real construction scenarios using spreadsheets. The article shows a complete computational experimentation over a real construction project, considering several scenarios of resource availabilities and continuity conditions. The model allows analyzing the resources efficiency indexes comparing them to resource consumptions, continuity of activities, and objective functions that reveal that fragmented activities do not provide better resource efficiency outcomes.
Gram-negative bacteria, such as Acinetobacter baumannii, are an increasing burden in hospitals worldwide with an alarming spread of multi-drug resistant (MDR) strains. Herein, we compared a type ...strain (ATCC17978), a non-clinical isolate (DSM30011) and MDR strains of A. baumannii implicated in hospital outbreaks (Ab242, Ab244 and Ab825), revealing distinct patterns of type VI secretion system (T6SS) functionality. The T6SS genomic locus is present and was actively transcribed in all of the above strains. However, only the A. baumannii DSM30011 strain was capable of killing Escherichia coli in a T6SS-dependent manner, unlike the clinical isolates, which failed to display an active T6SS in vitro. In addition, DSM30011 was able to outcompete ATCC17978 as well as Pseudomonas aeruginosa and Klebsiella pneumoniae, bacterial pathogens relevant in mixed nosocomial infections. Finally, we found that the T6SS of DSM30011 is required for host colonization of the model organism Galleria mellonella suggesting that this system could play an important role in A. baumannii virulence in a strain-specific manner.
This paper proposes a novel hybrid approach for feature selection in two different relevant problems for marine energy applications: significant wave height (Hm0) and wave energy flux (P) prediction. ...Specifically, a hybrid Grouping Genetic Algorithm – Extreme Learning Machine approach (GGA-ELM) is proposed, in such a way that the GGA searches for several subsets of features, and the ELM provides the fitness of the algorithm, by means of its accuracy on Hm0 or P prediction. Since the GGA was specifically created for problems involving a number of groups, the proposed algorithm may be used to evolve different groups of features in parallel, which may improve the performance of the predictions obtained. After the feature selection process with the GGA-ELM, the final results are given by an ELM and also by a Support Vector Machine, both working on the best GGA groups obtained. The performance of the proposed system has been tested in a real problem of Hm0 and P prediction at the Western coast of the USA, obtaining good results.
•A problem of Significant Wave Height prediction is tackled.•A hybrid GGA-ELM algorithm is proposed.•The GGA-ELM approach searches for the best set of features in the problem.•Experiments in real data of buoys located at the Western coast of the USA are carried out.
The length–tension curve in muscle depends on lattice spacing Williams, C. David; Salcedo, Mary K.; Irving, Thomas C. ...
Proceedings - Royal Society. Biological sciences/Proceedings - Royal Society. Biological Sciences,
09/2013, Letnik:
280, Številka:
1766
Journal Article
Recenzirano
Odprti dostop
Classic interpretations of the striated muscle length–tension curve focus on how force varies with overlap of thin (actin) and thick (myosin) filaments. New models of sarcomere geometry and ...experiments with skinned synchronous insect flight muscle suggest that changes in the radial distance between the actin and myosin filaments, the filament lattice spacing, are responsible for between 20% and 50% of the change in force seen between sarcomere lengths of 1.4 and 3.4 µm. Thus, lattice spacing is a significant force regulator, increasing the slope of muscle's force–length dependence.
The Transpose-Atmospheric Model Intercomparison Project (AMIP) is an international model intercomparison project in which climate models are run in “weather forecast mode.” The Transpose-AMIP II ...experiment is run alongside phase 5 of the Coupled Model Intercomparison Project (CMIP5) and allows processes operating in climate models to be evaluated, and the origin of climatological biases to be explored, by examining the evolution of the model from a state in which the large-scale dynamics, temperature, and humidity structures are constrained through use of common analyses.
The Transpose-AMIP II experimental design is presented. The project requests participants to submit a comprehensive set of diagnostics to enable detailed investigation of the models to be performed. An example of the type of analysis that may be undertaken using these diagnostics is illustrated through a study of the development of cloud biases over the Southern Ocean, a region that is problematic for many models. Several models share a climatological bias for too little reflected shortwave radiation from cloud across the region. This is found to mainly occur behind cold fronts and/or on the leading side of transient ridges and to be associated with more stable lower-tropospheric profiles. Investigation of a case study that is typical of the bias and associated meteorological conditions reveals the models to typically simulate cloud that is too optically and physically thin with an inversion that is too low. The evolution of the models within the first few hours suggests that these conditions are particularly sensitive and a positive feedback can develop between the thinning of the cloud layer and boundary layer structure.
COSP Bodas-Salcedo, A.; Webb, M. J.; Bony, S. ...
Bulletin of the American Meteorological Society,
08/2011, Letnik:
92, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Errors in the simulation of clouds in general circulation models (GCMs) remain a long-standing issue in climate projections, as discussed in the Intergovernmental Panel on Climate Change (IPCC) ...Fourth Assessment Report. This highlights the need for developing new analysis techniques to improve our knowledge of the physical processes at the root of these errors. The Cloud Feedback Model Intercomparison Project (CFMIP) pursues this objective, and under that framework the CFMIP Observation Simulator Package (COSP) has been developed. COSP is a flexible software tool that enables the simulation of several satellite-borne active and passive sensor observations from model variables. The flexibility of COSP and a common interface for all sensors facilitates its use in any type of numerical model, from high-resolution cloud-resolving models to the coarser-resolution GCMs assessed by the IPCC, and the scales in between used in weather forecast and regional models. The diversity of model parameterization techniques makes the comparison between model and observations difficult, as some parameterized variables (e.g., cloud fraction) do not have the same meaning in all models. The approach followed in COSP permits models to be evaluated against observations and compared against each other in a more consistent manner. This permits a more detailed diagnosis of the physical processes that govern the behavior of clouds and precipitation in numerical models. The World Climate Research Programme (WCRP) Working Group on Coupled Modelling has recommended the use of COSP in a subset of climate experiments that will be assessed by the next IPCC report. In this article we describe COSP, present some results from its application to numerical models, and discuss future work that will expand its capabilities.
Abstract Faced with the uncertainty of whether the vaccines against Covid-19 are effective or not and faced with living or dying, it is important to know the perception and expectation of their ...acceptance. The main aim of the study to analyze the perception and expectation of the vaccine against Covid- 19 that South American families have in an urban area of De Pasco. Descriptive, cross-sectional study, simple random sampling of 197 families. The participants were recruited digitally through a neighborhood leadership and an online survey was applied with prior consent. The logistic regression analysis was performed in EPIDAT 4.1 with a significance level of 5%. Regarding the desire to be vaccinated, it is worth noting that a family member died from the coronavirus, hence the health personnel must continue with the preventive promotional work of vaccination in order to obtain favorable results in the entire population. The majority (100%) have a favorable perception and expectation about the vaccine against Covid- 19 ( X c 2=132.83) and the p-value (0.00); As regards the desire to be vaccinated, it is worth noting having had a family member die from the coronavirus, hence the health personnel must continue with the preventive promotional work of vaccination in order to obtain favorable results in the entire population.
Resumo Diante da incerteza quanto à eficácia das vacinas contra a Covid-19 e diante da possibilidade de viver ou morrer, é importante conhecer a percepção e a expectativa de sua aceitação por parte da população. O objetivo principal do presente estudo é analisar a como a vacina contra a Covid-19 é vista pela população estudada e quais são as expectativas que famílias sul-americanas de uma área urbana de Pasco têm em relação a esta vacina. Este é um estudo descritivo, transversal, usando uma amostragem aleatória simples de 197 famílias. Os participantes foram selecionados digitalmente através do contato com uma liderança local e uma pesquisa online foi aplicada com o consentimento prévio dos indivíduos. A análise de regressão logística foi realizada no EPIDAT 4.1 com nível de significância de 5%. Acerca do desejo de se vacinar, é válido enfatizar que há falecimentos de familiares devido ao coronavírus e, portanto, é necessário que a equipe assistencial continue com o trabalho preventivo de incentivo à vacinação para obter resultados favoráveis para toda a população. De acordo com os resultados encontrados no presente estudo, a maioria (100%) dos participantes demonstrou ter uma percepção e expectativa favoráveis sobre a vacina contra a Covid-19 ( X c 2=132,83), com valor-p (0,00).
The efficient use of resources is a key factor to minimize the cost while meeting time deadlines and quality requirements; this is especially important in construction projects where field operations ...make fluctuations of resources unproductive and costly. Resource Leveling Problems (RLP) aim to sequence the construction activities that maximize the resource consumption efficiency over time, minimizing the variability. Exact algorithms for the RLP have been proposed throughout the years to offer optimal solutions; however, these problems require a vast computational capability (“combinatorial explosion”) that makes them unpractical. Therefore, alternative heuristic and metaheuristic algorithms have been suggested in the literature to find local optimal solutions, using different libraries to benchmark optimal values; for example, the Project Scheduling Problem LIBrary for minimal lags is still open to be solved to optimality for RLP. To partially fill this gap, the authors propose a Parallel Branch and Bound algorithm for the RLP with minimal lags to solve the RLP with an acceptable computational effort. This way, this research contributes to the body of knowledge of construction project scheduling providing the optimums of 50 problems for the RLP with minimal lags for the first time, allowing future contributors to benchmark their heuristics methods against exact results by obtaining the distance of their solution to the optimal values. Furthermore, for practitioners, the time required to solve this kind of problem is reasonable and practical, considering that unbalanced resources can risk the goals of the construction project.
In this work the effects of defects (oxygen vacancies, cationic inversion) on the structural, electronic and the magnetic response of the spinel ZnFe2O4 (ZFO) are studied by using a density ...functional theory (DFT) based ab initio method (the Full-Potential Linearized Augmented Plane Waves plus Local Orbitals, LAPW+lo) on the framework of the Generalized Gradient Approximation plus U (GGA+U) level. The changes induced by the defects in the hyperfine interactions at the Fe sites of the structure are also presented. In order to discuss the magnetic ordering and the electronic structure of the system we considered different spin arrangements. We found that, similar to the normal and pristine case, reduced and partially inverted ZFO presents an energy landscape characterized by a large number of metastable states. Our calculations successfully describe the hyperfine properties (isomer shift, magnetic hyperfine field and quadrupole splitting) at the Fe sites that are seen by Mössbauer Spectrocopy (MS) at 4 and 300 K, enabling us to characterize the local structure around Fe atoms. Our LAPW+lo predictions also demonstrate the relevance of both oxygen vacancies and antisites (cationic inversion) in the formation of local ferromagnetic coupling between Fe ions, giving rise to a ferrimagnetic ordering in an otherwise antiferromagnetic compound. This results support conclusions based in experimental results obtained in x-ray magnetic circular dichroism and magnetization measurements performed on zinc ferrites with different cation distributions and oxygen vacancy concentrations reported in the literature.
•DFT study of structural, electronic and magnetic properties of defective ZnFe2O4.•Prediction of the hyperfine parameters at Fe sites of reduced and inverted ZnFe2O4.•Characterization of the electronic and magnetic structure at the Fe sites.•Defects favour a ferromagnetic coupling of Fe atoms.•Oxygen vacancies and antisites give rise to a ferrimagnetic ordering of ZnFe2O4.
DFT with long-range corrections and ONIOM along with a polarizable-continuum model were used to analyze zeolites BEA, FAU, MFI, and BEC substituted with Sn and Ti. The preferential substitution sites ...for Ti and Sn in the different frameworks are reported. The Lewis acidities were measured through the NH3 binding energies and through the charge transfer of NH3 upon adsorption. The deprotonation energies of the open sites, which are proportional to the Brønsted acidities, and the hydrolysis energies are also reported. We also present the properties of BEA with a single and a double Sn-substitution to compare the active sites obtained with two methods commonly employed for the synthesis of Sn–BEA. Among the zeolites analyzed in this study, Sn–BEA with a double Sn-substitution has the highest Lewis acidity. The formation of open sites through the hydrolysis of Sn–BEA, Sn–FAU, and Ti–FAU is energetically favorable, but it is not favorable in MFI or Ti–BEA. On the basis of the deprotonation energies, the open sites of Sn–BEA have a strong Brønsted acidity, comparable to Al–BEA or Al–MFI. We also demonstrate that the VDW forces in the binding energies of NH3 on MFI are more significant than in the other zeolite frameworks and that these forces decrease with increasing pore size.
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