1,534 research outputs found
Foreword
Granites and Related Rocks: a tribute to Guillermo Corretgé (Geologica Acta 15, 4, Special Issue). Foreword
Fractal dimension and size scaling of domains in thin films of multiferroic BiFeO3
We have analyzed the morphology of ferroelectric domains in very thin films
of multiferroic BiFeO3. Unlike the more common stripe domains observed in
thicker films BiFeO3 or in other ferroics, the domains tend not to be straight,
but irregular in shape, with significant domain wall roughening leading to a
fractal dimensionality. Also contrary to what is usually observed in other
ferroics, the domain size appears not to scale as the square root of the film
thickness. A model is proposed in which the observed domain size as a function
of film thickness can be directly linked to the fractal dimension of the
domains.Comment: 4 pages, 3 figure
Regional Congruence of Vegetation and Summer Climate Patterns in the Queen Elizabeth Islands, Northwest Territories, Canada
In the Queen Elizabeth Islands, regional distributions of vegetation and many summer climate patterns show similar, distinctive S-shaped patterns, a response to the interaction between regional topography and persistent northwesterly flow from the central Arctic Ocean. The cool and cloudy central polar pack ice climate bulges almost unimpeded into the low-lying islands of the northwest and north-central sector. This region has the least vascular plant diversity and is dominated almost entirely by the herbaceous species. The mountains of Axel Heiberg and Ellesmere islands create a barrier that effectively shelters an intermontane region from both the central Arctic Ocean climate and travelling cyclonic systems. In this large intermontane zone regional minimums of cloud cover and maximums of temperatures and melt season duration are found. This area contains the most dense and diverse vascular plant assemblages. Woody species and sedges dominate, and many species with more southerly limits occur as disjuncts. The plateaus and highlands in the southern islands modify the central Arctic Ocean climate sufficiently to produce an intermediate climate. Woody species and sedges also dominate this area; however, the density and diversity are less than that of the intermontane area. Several phytogeographic limits occur in the Queen Elizabeth Islands, including the northern limits of woody plants and sedges, and the northern limits of the dominance of woody plants and sedges. These regional boundaries roughly coincide with regional mean July isotherms of 3 and 4°C respectively.Key words: Arctic, High Arctic, arctic vegetation, Canada, climate, summer climate, bioclimatic zones, Queen Elizabeth Islands, phytogeographical boundariesMots clés: Arctique, Extrême-Arctique, végétation arctique, Canada, climat, climat estival, zones bioclimatiques, îles de la Reine-Elizabeth, limites phytogéographique
Psychometric properties of the Dutch version of the Evidence-Based Practice Attitude Scale (EBPAS).
BackgroundThe Evidence-Based Practice Attitude Scale (EBPAS) was developed in the United States to assess attitudes of mental health and welfare professionals toward evidence-based interventions. Although the EBPAS has been translated in different languages and is being used in several countries, all research on the psychometric properties of the EBPAS within youth care has been carried out in the United States. The purpose of this study was to investigate the psychometric properties of the Dutch version of the EBPAS.MethodsAfter translation into Dutch, the Dutch version of the EBPAS was examined in a diverse sample of 270 youth care professionals working in five institutions in the Netherlands. We examined the factor structure with both exploratory and confirmatory factor analyses and the internal consistency reliability. We also conducted multiple linear regression analyses to examine the association of EBPAS scores with professionals' characteristics. It was hypothesized that responses to the EBPAS items could be explained by one general factor plus four specific factors, good to excellent internal consistency reliability would be found, and EBPAS scores would vary by age, sex, and educational level.ResultsThe exploratory factor analysis suggested a four-factor solution according to the hypothesized dimensions: Requirements, Appeal, Openness, and Divergence. Cronbach's alphas ranged from 0.67 to 0.89, and the overall scale alpha was 0.72. The confirmatory factor analyses confirmed the factor structure and suggested that the lower order EBPAS factors are indicators of a higher order construct. However, Divergence was not significantly correlated with any of the subscales or the total score. The confirmatory bifactor analysis endorsed that variance was explained both by a general attitude towards evidence-based interventions and by four specific factors. The regression analyses showed an association between EBPAS scores and youth care professionals' age, sex, and educational level.ConclusionsThe present study provides strong support for a structure with a general factor plus four specific factors and internal consistency reliability of the Dutch version of the EBPAS in a diverse sample of youth care professionals. Hence, the factor structure and reliability of the original version of the EBPAS seem generalizable to the Dutch version of the EBPAS
Psychometric Properties of the Malay Language Version of Knee Injury and Osteoarthritis Outcome Score (KOOS) Questionnaire among Knee Osteoarthritis Patients: A Confirmatory Factor Analysis
Introduction: This study aimed to cross-culturally adapt a
Malay version of Knee Injury and Osteoarthritis Outcome
Score (KOOS) and to evaluate its psychometric properties in
patients with knee osteoarthritis (OA).
Materials and Methods: The English version KOOS was
translated into a Malay version using forward and backward
translation process, followed by face validity and content
validity. Two hundred and twenty-six knee OA patients
attending the Outpatient and Orthopaedic Clinics, Universiti
Sains Malaysia Hospital, completed the Malay version
KOOS. Construct validity using confirmatory factor analysis
and internal reliability assessment were performed.
Results: The results showed that the original five-factor
model with 42 items failed to achieve acceptable values of
the goodness of fit indices, indicating poor model fit. A new
five-factor model of 26 items demonstrated acceptable level
of goodness of fit (comparative fit index= 0.929, incremental
fit index= 0.930, Tucker Lewis fit index= 0.920, root mean
square error of approximation= 0.073 and Chisquared/
degree of freedom= 2.183) indices to signify a
model fit. The Cronbach’s alpha value for the new model
ranged from 0.776 to 0.946. The composite reliability values
of each construct ranged between 0.819 and 0.921,
indicating satisfactory to high level of convergent validity.
Conclusion: The five-factor model with 26 items in the
Malay version of KOOS questionnaire demonstrated a good
degree of goodness of fit and was found to be valid, reliable
and simple as an assessment tool for symptoms, pain,
activity of daily living, sports and recreational activity and
quality of life for Malaysian adults suffering from knee
osteoarthritis
Mining for viral fragments in methylation enriched sequencing data
Most next generation sequencing experiments generate more data than is required for the experimental set up. For example, methyl-CpG binding domain (MBD) affinity purification based sequencing is often used for DNA-methylation profiling, but up to 30% of the sequenced fragments cannot be mapped uniquely to the reference genome. Here we present and evaluate a methodology for the identification of viruses in these otherwise unused paired-end MBD-seq data. Viral detection is accomplished by mapping non-reference alignable reads to a comprehensive set of viral genomes. As viruses play an important role in epigenetics and cancer development, 92 (pre)malignant and benign samples, originating from two different collections of cervical samples and related cell lines, were used in this study. These samples include primary carcinomas (n=22), low- & high-grade cervical intrapeithelial neoplasia (CIN1 & CIN2/3 - n=2/n=30) and normal tissue (n=20), as well as control samples (n=17). Viruses that were detected include phages, adenoviruses, herpesviridae and HPV. HPV, which causes virtually all cervical cancers, was identified in 95% of the carcinomas, 100% of the CIN2/3 samples, both CIN1 samples and in 55% of the normal samples. Comparing the amount of mapped fragments on HPV for each HPV-infected sample yielded a significant difference between normal samples and carcinomas or CIN2/3 samples (adjusted p-values resp. < 10^-5, < 10^-5), reflecting different viral loads and/or methylation degrees in non-normal samples. Fragments originating from different HPV types could be distinguished and were independently validated by PCR-based assays with a specificity of 98% and a sensitivitity of 66%. In conclusion, although limited by the a priori knowledge of viral reference genome sequences, the proposed methodology can provide a first but substantial insight into the presence, concentration and types of methylated viral sequences in MBD-seq data without additional costs
Flow dynamics of Byrd Glacier, East Antarctica
This is the published version. Copyright 2014Force-balance calculations on Byrd Glacier, East Antarctica, reveal large spatial variations in the along-flow component of driving stress with corresponding sticky spots that are stationary over time. On the large scale, flow resistance is partitioned between basal (∼80%) and lateral (∼20%) drag. Ice flow is due mostly to basal sliding and concentrated vertical shear in the basal ice layers, indicating the bed is at or close to the pressure-melting temperature. There is a significant component of driving stress in the across-flow direction resulting in nonzero basal drag in that direction. This is an unrealistic result and we propose that there are spatial variations of bed features resulting in small-scale flow disturbances. The grounding line of Byrd Glacier is located in a region where the bed slopes upward. Nevertheless, despite a 10% increase in ice discharge between December 2005 and February 2007, following drainage of two subglacial lakes in the catchment area, the position of the grounding line has not retreated significantly and the glacier has decelerated since then. During the speed-up event, partitioning of flow resistance did not change, suggesting the increase in velocity was caused by a temporary decrease in basal effective pressure
Genome-wide methylome analysis using MethylCap-seq uncovers 4 hypermethylated markers with high sensitivity for both adeno- and squamous-cell cervical carcinoma
Background: Cytology-based screening methods for cervical adenocarcinoma (ADC) and to a lesser extent squamous-cell carcinoma (SCC) suffer from low sensitivity. DNA hypermethylation analysis in cervical scrapings may improve detection of SCC, but few methylation markers have been described for ADC. We aimed to identify novel methylation markers for the early detection of both ADC and SCC.
Results: Genome-wide methylation profiling for 20 normal cervices, 6 ADC and 6 SCC using MethylCap-seq yielded 53 candidate regions hypermethylated in both ADC and SCC. Verification and independent validation of the 15 most significant regions revealed 5 markers with differential methylation between 17 normals and 13 cancers. Quantitative methylation-specific PCR on cervical cancer scrapings resulted in detection rates ranging between 80% and 92% while between 94% and 99% of control scrapings tested negative. Four markers (SLC6A5, SOX1, SOX14 and TBX20) detected ADC and SCC with similar sensitivity. In scrapings from women referred with an abnormal smear (n = 229), CIN3+ sensitivity was between 36% and 71%, while between 71% and 93% of adenocarcinoma in situ (AdCIS) were detected; and CIN0/1 specificity was between 88% and 98%. Compared to hrHPV, the combination SOX1/SOX14 showed a similar CIN3+ sensitivity (80% vs. 75%, respectively, P>0.2), while specificity improved (42% vs. 84%, respectively, P < 10(-5)).
Conclusion: SOX1 and SOX14 are methylation biomarkers applicable for screening of all cervical cancer types
Tourmaline 40Ar/39Ar chronology of tourmaline-rich rocks from Central Iberia dates the main Variscan deformation phases
During crustal thickening, metapelites taken to depth release boron-bearing hydrothermal fluids because of progressive heating and dehydration. These fluids swiftly percolate upwards, especially if the crust is being actively deformed, to form tourmaline where the PT conditions and the chemical composition of the host-rock are favorable. The age of the so-formed tourmaline would record the age of the upward admittance of B-bearing fluids and, presumably, the age of the deformation. This process has been documented in the Martinamor Antiform of Central Iberia, a region where tourmaline-bearing rocks are particularly abundant. Metasomatic tourmaline from the Late Cambrian San Pelayo orthogneisses (zircon U-Pb age of 496 ± 5 Ma) yielded 40Ar/39Ar plateau ages at 370 ± 5 Ma and 342 ± 5 Ma. The first value represents the crystallization age of the tourmaline and is so far the most precise estimation of the age of crustal thickening in Central Iberia (D1). The second value reflects a partial loss of Ar caused by the second deformation phase (D2). Tourmaline from mylonitized and folded tourmalinites developed above D2 shear zones yield perturbed spectra with mean "plateau" ages of 347 ± 9 Ma and 342 ± 9 Ma which may represent either the resetting of older tourmaline or the formation of new tourmaline by focused boron metasomatism. After the metamorphic peak and simultaneously with the emplacement of the main granitoids of the Avila Batholith (310-315 Ma), another episode of boron metasomatism precipitated a new generation of tourmaline, which appears either concentrated in fine-layered tourmalinites (318 ± 2 Ma) or disseminated within Ediacaran-Cambrian metasediments (316 ± 2 Ma). The source of boron was the breakdown of previously formed tourmaline during melting reactions. Lastly, tourmaline from a leucogranitic body yielded a saddle-shaped age spectrum with a minimum age of ca. 296 Ma, roughly coeval with the youngest leucograni - tes. Although further work is required, our results suggest that tourmaline can be a useful chronological marker for dating deformation and magmatism
Virtual active power sensor for eolic self-consumption installations based on wind-related variables
Funding for open access charge: Universidade da Coruña/CISUG.Xunta de Galicia; ED481A-2023-072Xunta de Galicia; IN853C 2022/01Xunta de Galicia; ED431G 2023/01Interreg Altantic Area, EAPA_0019/2022Antonio Díaz-Longueira’s research was supported by the Xunta de Galicia (Regional Government of Galicia) through grants to Ph.D. (http://gain.xunta.gal), under the ‘Axudas á etapa predoutoral’ grant with reference: ED481A-2023-072. This work has been supported by Xunta de Galicia through Axencia Galega de Innovación (GAIN) by grant IN853C 2022/01, Centro Mixto de Investigación UDC-NAVANTIA ‘O estaleiro do futuro’, which is ongoing until the end of September 2025. The support was inherited from both the starting and consolidation stages of the same project throughout 2015–2018 and 2018–2021, respectively. This stage is also co-funded by ERDF funds from the EU in the framework of program FEDER Galicia 2021–2027. CITIC, as a center accredited for excellence within the Galician University System and a member of the CIGUS Network, receives subsidies from the Department of Education, Science, Universities and Vocational Training of the Xunta de Galicia. Additionally, it is co-financed by the EU through the FEDER Galicia 2021–27 operational program (Ref. ED431G 2023/01). Xunta de Galicia. Grants for the consolidation and structuring of competitive research units, GPC (ED431B 2023/49). This research is co-financed by the Interreg Atlantic Area Programme through the European Regional Development Fund, EAPA_0019/2022 SAtComm project
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