537 research outputs found
Combining satellite data and appropriate objective functions for improved spatial pattern performance of a distributed hydrologic model
Abstract. Satellite-based earth observations offer great opportunities to improve spatial model predictions by means of spatial-pattern-oriented model evaluations. In this study, observed spatial patterns of actual evapotranspiration (AET) are utilised for spatial model calibration tailored to target the pattern performance of the model. The proposed calibration framework combines temporally aggregated observed spatial patterns with a new spatial performance metric and a flexible spatial parameterisation scheme. The mesoscale hydrologic model (mHM) is used to simulate streamflow and AET and has been selected due to its soil parameter distribution approach based on pedo-transfer functions and the build in multi-scale parameter regionalisation. In addition two new spatial parameter distribution options have been incorporated in the model in order to increase the flexibility of root fraction coefficient and potential evapotranspiration correction parameterisations, based on soil type and vegetation density. These parameterisations are utilised as they are most relevant for simulated AET patterns from the hydrologic model. Due to the fundamental challenges encountered when evaluating spatial pattern performance using standard metrics, we developed a simple but highly discriminative spatial metric, i.e. one comprised of three easily interpretable components measuring co-location, variation and distribution of the spatial data. The study shows that with flexible spatial model parameterisation used in combination with the appropriate objective functions, the simulated spatial patterns of actual evapotranspiration become substantially more similar to the satellite-based estimates. Overall 26 parameters are identified for calibration through a sequential screening approach based on a combination of streamflow and spatial pattern metrics. The robustness of the calibrations is tested using an ensemble of nine calibrations based on different seed numbers using the shuffled complex evolution optimiser. The calibration results reveal a limited trade-off between streamflow dynamics and spatial patterns illustrating the benefit of combining separate observation types and objective functions. At the same time, the simulated spatial patterns of AET significantly improved when an objective function based on observed AET patterns and a novel spatial performance metric compared to traditional streamflow-only calibration were included. Since the overall water balance is usually a crucial goal in hydrologic modelling, spatial-pattern-oriented optimisation should always be accompanied by traditional discharge measurements. In such a multi-objective framework, the current study promotes the use of a novel bias-insensitive spatial pattern metric, which exploits the key information contained in the observed patterns while allowing the water balance to be informed by discharge observations.</jats:p
Principios básicos de resonancia magnética cardiovascular (RMC): secuencias, planos de adquisición y protocolo de estudio
ABSTRACT
Evaluation of the cardiovascular system with
magnetic resonance (CMR) has become one of the most
relevant and up-to-the-minute clinical applications of
this diagnostic technique, as CMR makes possible an
exact and reproducible study of the anatomy and
function of the heart and great vessels. The complexity
of this technique is mainly due to the anatomical
location and orientation of the cardiovascular
structures, the specific CMR sequences that have to be
used and a lack of familiarity amongst radiologists
regarding cardiovascular pathology. In this report the
most basic principles of CMR are described. The clinical
usefulness of anatomical, functional, and flow
quantification sequences are discussed, conventional
CMR acquisition planes are described, and an easy CMR
study protocol is proposed
Myocardial extracellular volume quantification by cardiovascularagn magnetic resonance and computed tomography
Purpose of review This review article discusses the evolution of extracellular volume (ECV) quantification using both cardiovascular magnetic resonance (CMR) and computed tomography (CT).
Recent findings Visualizing diffuse myocardial fibrosis is challenging and until recently, was restricted to the domain of the
pathologist. CMR and CT both use extravascular, extracellular contrast agents, permitting ECV measurement. The evidence base
around ECV quantification by CMR is growing rapidly and just starting in CT. In conditions with high ECV (amyloid, oedema
and fibrosis), this technique is already being used clinically and as a surrogate endpoint. Non-invasive diffuse fibrosis quantification is also generating new biological insights into key cardiac diseases.
Summary CMR and CT can estimate ECV and in turn diffuse myocardial fibrosis, obviating the need for invasive
endomyocardial biopsy. CT is an attractive alternative to CMR particularly in those individuals with contraindications to the
latter. Further studies are needed, particularly in CT
A Pasteurella multocida strain affecting nulliparous heifers and calves in different ways
Pasteurella multocida isolates from dairy cattle on a farm in Spain were associated with pneumonia of calves (six isolates) and mastitis of heifers (five isolates). The objective was to determine if the P. multocida isolates retrieved from both disease scenarios were the same strain or whether more than one strain was present. The isolates were identified by a species-specific polymerase chain (PCR) assay, serotyped by the Heddleston scheme and then typed by a number of molecular genotyping assays including multi-locus sequence typing (MLST). The 11 isolates were confirmed as P. multocida but failed to react with any of the 16 Heddleston antisera. The PCR targeting the genes associated with the lipopolysaccharide outer core biosynthesis locus assigned all the isolates to L3–the type that contains Heddleston serovars 3 and 4. The MLST analysis showed all isolates belonging to ST 79 within the clonal complex of ST13. Only one of the isolates showed a slight different profile by the repetitive extragenic palindromic PCR. The conclusion was that the same strain was associated with pneumonia in calves and mastitis in heifers
Methodology for design of suitable dishes for dysphagic people
A methodology to adapt dishes for cerebral palsy (CP) dysphagic people was developed. Five conventional dishes were cooked, blended and texturized with mixtures of thickeners and gelling agents based on xanthan gum. The most appropriate texturizing agents were selected, the textural thermostability of the dishes was studied, and the shelf-life was evaluated by back extrusion, sensory and microbiology analysis. Information about the acceptability of the adapted dishes by CP dysphagic people was obtained through the control of the consumed fraction and the liking or disliking reaction after eating the dishes. The adapted dishes considered suitable for swallowing process showed maximum force between 6.2(0.1) N and 18.9(3.3) N, minimum force between −3.9(0.3) N and −9.2(1.3) N, and Fmin/Fmax ratio between 0.4(0.0) and 0.7(0.0). Regarding sensory characteristics, the adapted dishes showed low stickiness, residue and firmness, and high suitable texture score. The methodology was appropriate for developing suitable dishes, sensorially accepted by dysphagic people, thermostable for 7 days refrigerated storage and ready-to-eat. Industrial relevance: This study presents the technological basis for the standardized design of suitable ready-to-eat dishes for dysphagic people. The methodology developed is of great interest to the industry of ready-to-eat dishes.This study has been partially financed by the European Regional Development Fund through the 2014-2020 FEDER Operational Program of Navarre and by Navarre Government through the Programme 'AYUDAS PARA REALIZAR PROYECTOS DE I+D - Convocatoria 2017' (PEP E-14/000107-01)
Exploring genetic factors involved in huntington disease age of onset. E2F2 as a new potential modifier gene
Age of onset (AO) of Huntington disease (HD) is mainly determined by the length of the CAG repeat expansion (CAGexp) in exon 1 of the HTT gene. Additional genetic variation has been suggested to contribute to AO, although the mechanism by which it could affect AO is presently unknown. The aim of this study is to explore the contribution of candidate genetic factors to HD AO in order to gain insight into the pathogenic mechanisms underlying this disorder. For that purpose, two AO definitions were used: the earliest age with unequivocal signs of HD (earliest AO or eAO), and the first motor symptoms age (motor AO or mAO). Multiple linear regression
analyses were performed between genetic variation within 20 candidate genes and eAO or mAO, using DNA and clinical information of 253 HD patients from REGISTRY project. Gene expression analyses were carried out by RT-qPCR with an independent sample of 35 HD patients from Basque Country Hospitals. We found suggestive association signals between HD eAO and/or mAO and genetic variation within the E2F2, ATF7IP, GRIN2A, GRIN2B, LINC01559, HIP1 and GRIK2 genes. Among them, the most significant was the association between eAO and rs2742976, mapping to the promoter region of E2F2 transcription factor.
Furthermore, rs2742976 T allele patient carriers exhibited significantly lower lymphocyte E2F2 gene expression, suggesting a possible implication of E2F2-dependent transcriptional activity in HD pathogenesis. Thus, E2F2 emerges as a new potential HD AO modifier factor
Total body CD4+ T cell dynamics in treated and untreated SIV infection revealed by in vivo imaging
The peripheral blood represents only a small fraction of the total number of lymphocytes in the body. To develop a more thorough understanding of T cell dynamics, including the effects of SIV/SHIV/HIV infection on immune cell depletion and immune reconstitution following combination antiretroviral therapy (cART), one needs to utilize approaches that allow direct visualization of lymphoid tissues. In the present study, noninvasive in vivo imaging of the CD4+ T cell pool has revealed that the timing of the CD4+ T cell pool reconstitution following initiation of ART in SIV-infected nonhuman primates (NHPs) appears seemingly stochastic among clusters of lymph nodes within the same host. At 4 weeks following initiation or interruption of cART, the changes observed in peripheral blood (PB) are primarily related to changes in the whole-body CD4 pool rather than changes in lymphocyte trafficking. Lymph node CD4 pools in long-term antiretroviral-treated and plasma viral load-suppressed hosts appear suboptimally reconstituted compared with healthy controls, while splenic CD4 pools appear similar between the 2 groups
Plasma Rich in Growth Factors Membrane as Coadjuvant Treatment in the Surgery of Ocular Surface Disorders
To evaluate the safety and efficacy of the surgical use of plasma rich in growth factors fibrin membrane (mPRGF) in different ocular surface pathologies.Fifteen patients with different corneal and conjunctival diseases were included in the study. Patients were grouped according to the use of mPRGF as graft (corneal and/or conjunctival) or dressing; they were also grouped according to the surgical subgroup of intervention (persistent corneal ulcer [PCU], keratoplasty, superficial keratectomy, corneal perforation, and pterygium). Best corrected visual acuity, intraocular pressure (IOP), inflammation control time (ICT), mPRGF AT (PRGF membrane absorption time), and the healing time of the epithelial defect (HTED) were evaluated throughout the clinical follow-up time. Safety assessment was also performed reporting all adverse events.mPRGF showed a total closure of the defect in 13 of 15 patients (86.7%) and a partial closure in 2 patients (13.3%). The mean follow-up time was 11.14.2 (4.8-22.8) months, the mean ICT was 2.5 +/- 1.1 (1.0-4.0) months, the mean mPRGF AT was 12.4 +/- 2.0 (10.0-16.0) days, and for the global HTED the mean was 2.9 +/- 1.2 (1-4.8) months. Results showed an improvement in BCVA in all patients, with an overall improvement of 2.9 in Vision Lines. The BCVA significantly improved (P.05) throughout the clinical follow-up time. No adverse events were reported after mPRGF use.The mPRGF is effective and safe as coadjuvant treatment in surgeries related with ocular surface disorders, being an alternative to the use of amniotic membrane. The mPRGF accelerates tissue regeneration after ocular surface surgery thus minimizing inflammation and fibrosis.This study received funding from the Ministry of Economy and Competitiveness of the Spanish Government, within the project denominated SURFEYE (reference RTC-2014-2375-1)
- …