136 research outputs found
An ordinal multi-criteria decision-making procedure in the context of uniform qualitative scales
Producción CientíficaIn this contribution, we propose a multi-criteria decision-making procedure that has been devised in a purely ordinal way. Agents evaluate the alternatives regarding several criteria by assigning one or two consecutive terms of a uniform ordered qualitative scale to each alternative in each criterion. Weights assigned to criteria are managed through replications of the corresponding ratings, and alternatives are ranked according to the medians of their ratings after the replications
A multi-collaborative ambient assisted living service description tool
Collaboration among different stakeholders is a key factor in the design of Ambient Assisted Living (AAL) environments and services. Throughout several AAL projects we have found repeated difficulties in this collaboration and have learned lessons by the experience of solving real situations. This paper highlights identified critical items for collaboration among technicians, users, company and institutional stakeholders and proposes as a communication tool for a project steering committee a service description tool which includes information from the different fields in comprehensible format for the others. It was first generated in the MonAMI project to promote understanding among different workgroups, proven useful there, and further tested later in some other smaller AAL projects. The concept of scalable service description has proven useful for understanding of different disciplines and for participatory decision making throughout the projects to adapt to singularities and partial successes or faults of each action. This paper introduces such tool, relates with existing methodologies in cooperation in AAL and describes it with a example to offer to AAL community. Further work on this tool will significantly improve results in user-centered design of sustainable services in AAL
Quantifying tissue growth, shape and collision via continuum models and Bayesian inference
Although tissues are usually studied in isolation, this situation rarely occurs in biology, as cells, tissues, and organs, coexist and interact across scales to determine both shape and function. Here, we take a quantitative approach combining data from recent experiments, mathematical modelling, and Bayesian parameter inference, to describe the self-assembly of multiple epithelial sheets by growth and collision. We use two simple and well-studied continuum models, where cells move either randomly or following population pressure gradients. After suitable calibration, both models prove to be practically identifiable, and can reproduce the main features of single tissue expansions. However, our findings reveal that whenever tissue-tissue interactions become relevant, the random motion assumption can lead to unrealistic behaviour. Under this setting, a model accounting for population pressure from different cell populations is more appropriate and shows a better agreement with experimental measurements. Finally, we discuss how tissue shape and pressure affect multi-tissue collisions. Our work thus provides a systematic approach to quantify and predict complex tissue configurations with applications in the design of tissue composites and more generally in tissue engineering
A separated representation involving multiple time scales within the Proper Generalized Decomposition framework
Solutions of partial differential equations can exhibit multiple time scales. Standard discretization techniques are constrained to capture the finest scale to accurately predict the response of the system. In this paper, we provide an alternative route to circumvent prohibitive meshes arising from the necessity of capturing fine-scale behaviors. The proposed methodology is based on a time-separated representation within the standard Proper Generalized Decomposition, where the time coordinate is transformed into a multi-dimensional time through new separated coordinates, each representing one scale, while continuity is ensured in the scale coupling. For instance, when considering two different time scales, the governing Partial Differential Equation is commuted into a nonlinear system that iterates between the so-called microtime and macrotime, so that the time coordinate can be viewed as a 2D time. The macroscale effects are taken into account by means of a finite element-based macro-discretization, whereas the microscale effects are handled with unidimensional parent spaces that are replicated throughout the time domain. The resulting separated representation allows us a very fine time discretization without impacting the computational efficiency. The proposed formulation is explored and numerically verified on thermal and elastodynamic problems. © 2021, The Author(s)
Testing the Psychometric Properties and Measurement Invariance of the Perceived Motivational Climate in Sport Questionnaire (PMCSQ-2): Online Assessment
Athletes’ perception of competence and success can be influenced by the motivational climate created by the coach. The Perceived Motivational Climate in Sport Questionnaire (PMCSQ-2) assesses this. Although its reliability and validity have been analyzed in previous studies, this has never been done for the online version. This type of evaluation can be beneficial for data collection, sustainability, speed, and generating larger samples. Therefore, the aim of this study is to analyze the psychometric properties of the PMCSQ-2 in its online version. The sample consisted of 1637 participants (37.8% men and 62.2% women) from 18 to 68 years of age (M = 24.39, SD = 6.51) who practiced physical-sport activities regularly. A second-order confirmatory factor analysis (CFA) model and its invariance for gender were studied from a 24-item version obtained from the MenPas 1.0 platform. The analyses provided an adequate fit for the CFA (CFI = 0.91, TLI = 0.90, RMSEA = 0.07, SRMR = 0.07, df = 224, B-S p = 0.02–0.07) when an alternative model was realized (χ2 = 1858.89, χ2/df = 8.30), as they also did for the women (χ2 = 1356.90, χ2/df = 6.06), men (χ2 = 883.58, χ2/df = 3.95) individual sports (χ2 = 1153.55, χ2/df = 5.15), and team sports (χ2 = 1008.92, χ2/df = 4.05) items. The data were also suitable for invariance analysis. Similarly, appropriate values were obtained for convergent and discriminant validity and for composite reliability. Therefore, the results obtained show appropriate psychometric properties for the online version of the PMCSQ-2 using an alternative model, suggesting that its use is suitable for research and showing the importance of the subscales.Partial funding for open access charge: Universidad de Málag
Mytilus galloprovincialis Myticin C: A Chemotactic Molecule with Antiviral Activity and Immunoregulatory Properties
Previous research has shown that an antimicrobial peptide (AMP) of the myticin class C (Myt C) is the most abundantly expressed gene in cDNA and suppressive subtractive hybridization (SSH) libraries after immune stimulation of mussel Mytilus galloprovincialis. However, to date, the expression pattern, the antimicrobial activities and the immunomodulatory properties of the Myt C peptide have not been determined. In contrast, it is known that Myt C mRNA presents an unusual and high level of polymorphism of unidentified biological significance. Therefore, to provide a better understanding of the features of this interesting molecule, we have investigated its function using four different cloned and expressed variants of Myt C cDNA and polyclonal anti-Myt C sera. The in vivo results suggest that this AMP, mainly present in hemocytes, could be acting as an immune system modulator molecule because its overexpression was able to alter the expression of mussel immune-related genes (as the antimicrobial peptides Myticin B and Mytilin B, the C1q domain-containing protein MgC1q, and lysozyme). Moreover, the in vitro results indicate that Myt C peptides have antimicrobial and chemotactic properties. Their recombinant expression in a fish cell line conferred protection against two different fish viruses (enveloped and non-enveloped). Cell extracts from Myt C expressing fish cells were also able to attract hemocytes. All together, these results suggest that Myt C should be considered not only as an AMP but also as the first chemokine/cytokine-like molecule identified in bivalves and one of the few examples in all of the invertebrates
Long-term vegetation dynamics of a tropical megadelta: Mid-Holocene palaeoecology of the Orinoco Delta (NE Venezuela)
© 2019 Elsevier Ltd Coastal wetlands have been proposed as highly threatened by the ongoing and future climatic change, including projected sea-level changes as an additional forcing factor compared to more inland locations. The limited knowledge generated to date in this topic has been primarily focused on those areas attaining a high population density, and rarely deals with long-term (>50 years) dynamics. Here we present the first Holocene palaeoecological study carried in the Orinoco Delta, in NE Venezuela. The record presented here contains sediments from the last 6200 years and is located in a river-shore swamp dominated by the palm Mauritia flexuosa. Current human occupation is almost restricted to small settlements of the Warao indigenous culture, closely related to the use of M. flexuosa and other palm species present in the zone. The results show the occurrence of three well-distinguished palynological zones: (i) from 6200 to 5200 cal yr BP, characterised by mixed rainforest and other taxa related to salinity (coastal-like), low (negative) values of magnetic susceptibility and magnetic grain size, absence of transported clays, and the highest macrocharcoal particles abundance; (ii) from 5200 to 2950 cal yr BP, marked by a replacement of the mangrove-like vegetation by a more inland mixed-swamp forest community with low levels of charcoal, and (iii) from 2950 cal yr BP to present-day, characterised by the establishment of the current vegetation community, dominated by M. flexuosa, and an increasing trend in the charcoal curve since the last 700 years. A combination of regional (climatic changes) and local (sediment ontogeny) has been proposed as the key drivers influencing the vegetation succession recorded. The stabilisation of the sea-level that occurred during the mid-Holocene would have favoured the transgression of the coastal line, with the migration of the coastal-like vegetation seawards. Synchronous to this event, a trend towards drier conditions has been reported in the close Cariaco record, that could have also influenced the vegetation replacement. Between 3800 and 2800 years ago, the increased ENSO variability registered in Cariaco may have played a key role in the expansion of the Mauritia palm community. It is suggested that in our location, the potential inhabiting human populations were differently influenced by these environmental changes. First, the disappearance of the coastal resources could have favoured land abandonment, whereas the increase in the abundance of the palm might be influential for the arrival of other inland cultures that were previously used to manage Mauritia. This sequence shows the importance of the ecosystem services for the location inhabitants, highlighting the abandonment of the mid-Holocene culture coeval with the disappearance of its ecosystem. These results also provide information about the sensitivity and resilience in facing external stressors of both humans and vegetation, and will be valuable tools for managing the future of this ecosystem
Tensor completion in hierarchical tensor representations
Compressed sensing extends from the recovery of sparse vectors from
undersampled measurements via efficient algorithms to the recovery of matrices
of low rank from incomplete information. Here we consider a further extension
to the reconstruction of tensors of low multi-linear rank in recently
introduced hierarchical tensor formats from a small number of measurements.
Hierarchical tensors are a flexible generalization of the well-known Tucker
representation, which have the advantage that the number of degrees of freedom
of a low rank tensor does not scale exponentially with the order of the tensor.
While corresponding tensor decompositions can be computed efficiently via
successive applications of (matrix) singular value decompositions, some
important properties of the singular value decomposition do not extend from the
matrix to the tensor case. This results in major computational and theoretical
difficulties in designing and analyzing algorithms for low rank tensor
recovery. For instance, a canonical analogue of the tensor nuclear norm is
NP-hard to compute in general, which is in stark contrast to the matrix case.
In this book chapter we consider versions of iterative hard thresholding
schemes adapted to hierarchical tensor formats. A variant builds on methods
from Riemannian optimization and uses a retraction mapping from the tangent
space of the manifold of low rank tensors back to this manifold. We provide
first partial convergence results based on a tensor version of the restricted
isometry property (TRIP) of the measurement map. Moreover, an estimate of the
number of measurements is provided that ensures the TRIP of a given tensor rank
with high probability for Gaussian measurement maps.Comment: revised version, to be published in Compressed Sensing and Its
Applications (edited by H. Boche, R. Calderbank, G. Kutyniok, J. Vybiral
Phase II study of high-sensitivity genotyping of KRAS, NRAS, BRAF and PIK3CA to ultra-select metastatic colorectal cancer patients for panitumumab plus FOLFIRI: the ULTRA trial
Background: Several studies show the importance of accurately quantifying not only KRAS and other low-abundant mutations because benefits of anti-EGFR therapies may depend on certain sensitivity thresholds. We assessed whether ultra-selection of patients using a high-sensitive digital PCR (dPCR) to determine KRAS, NRAS, BRAF and PIK3CA status can improve clinical outcomes of panitumumab plus FOLFIRI. Patients and methods: This was a single-arm phase II trial that analysed 38 KRAS, NRAS, BRAF and PIK3CA hotspots in tumour tissues of irinotecan-resistant metastatic colorectal cancer patients who received panitumumab plus FOLFIRI until disease progression or early withdrawal. Mutation profiles were identified by nanofluidic dPCR and correlated with clinical outcomes (ORR, overall response rate; PFS, progression-free survival; OS, overall survival) using cut-offs from 0% to 5%. A quantitative PCR (qPCR) analysis was also performed. Results: Seventy-two evaluable patients were enrolled. RAS (KRAS/NRAS) mutations were detected in 23 (32%) patients and RAS/BRAF mutations in 25 (35%) by dPCR, while they were detected in 7 (10%) and 11 (15%) patients, respectively, by qPCR. PIK3CA mutations were not considered in the analyses as they were only detected in 2 (3%) patients by dPCR and in 1 (1%) patient by qPCR. The use of different dPCR cut-offs for RAS (KRAS/NRAS) and RAS/BRAF analyses translated into differential clinical outcomes. The highest ORR, PFS and OS in wild-type patients with their lowest values in patients with mutations were achieved with a 5% cut-off. We observed similar outcomes in RAS/BRAF wild-type and mutant patients defined by qPCR. Conclusions: High-sensitive dPCR accurately identified patients with KRAS, NRAS, BRAF and PIK3CA mutations. The optimal RAS/BRAF mutational cut-off for outcome prediction is 5%, which explains that the predictive performance of qPCR was not improved by dPCR. The biological and clinical implications of low-frequent mutated alleles warrant further investigations
Functional characterization of a GGPPS variant indentified in atypical femoral fracture patients and delineation of the role of GGPPS in bone-relevant cell types
Atypical femoral fractures (AFFs) are a rare but potentially devastating event, often but not always linked to bisphosphonate (BP) therapy. The pathogenic mechanisms underlying AFFs remain obscure, and there are no tests available that might assist in identifying those at high risk of AFF. We previously used exome sequencing to explore the genetic background of three sisters with AFFs and three additional unrelated AFF cases, all previously treated with BPs. We detected 37 rare mutations (in 34 genes) shared by the three sisters. Notably, we found a p.Asp188Tyr mutation in the enzyme geranylgeranyl pyrophosphate synthase, a component of the mevalonate pathway, which is critical to osteoclast function and is inhibited by N-BPs. In addition, the CYP1A1 gene, responsible for the hydroxylation of 17β-estradiol, estrone, and vitamin D, was also mutated in all three sisters and one unrelated patient. Here we present a detailed list of the variants found and report functional analyses of the GGPS1 p.Asp188Tyr mutation, which showed a severe reduction in enzyme activity together with oligomerization defects. Unlike BP treatment, this genetic mutation will affect all cells in the carriers. RNAi knockdown of GGPS1 in osteoblasts produced a strong mineralization reduction and a reduced expression of osteocalcin, osterix, and RANKL, whereas in osteoclasts, it led to a lower resorption activity. Taken together, the impact of the mutated GGPPS and the relevance of the downstream effects in bone cells make it a strong candidate for AFF susceptibility. We speculate that other genes such as CYP1A1 might be involved in AFF pathogenesis, which remains to be functionally proved. The identification of the genetic background for AFFs provides new insights for future development of novel risk assessment tools. © 2018 American Society for Bone and Mineral Research
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