124 research outputs found

    Cardiovascular System in Preeclampsia and Beyond.

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    High-Frequency Attenuation in the Lake Van Region, Eastern Turkey

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    We provide a complete description of the characteristics of excitation and attenuation of the ground motion in the Lake Van region (eastern Turkey) using a data set that includes three-component seismograms from the 23 October 2011 Mw 7.1 Van earthquake, as well as its aftershocks. Regional attenuation and source scaling are parameterized to describe the observed ground motions as a function of distance, frequency, and magnitude. Peak ground velocities are measured in selected narrow frequency bands from 0.25 to 12.5 Hz; observed peaks are regressed to define a piecewise linear regional attenu- ation function, a set of excitation terms, and a set of site response terms. Results are modeled through random vibration theory (see Cartwright and Longuet-Higgins, 1956). In the log–log space, the regional crustal attenuation is modeled with a bilinear geo- metrical spreading g r characterized by a crossover distance at 40 km: g r ∝ r^−1 fits our results at short distances (r < 40 km), whereas g r ∝ r^−0.3 is better at larger distances (40 < r < 200 km). A frequency-dependent quality factor, Q f =100( f/fref)^ 0:43 (in which fref 1.0 Hz), is coupled to the geometrical spreading. Because of the inherent trade-off of the excitation/attenuation parameters (Δσ and κ), their specific values strongly depend on the choice made for the stress drop of the smaller earthquakes. After choosing a Brune stress drop ΔσBrune 4 MPa at Mw 3:5, we were able to define (1) an effective high frequency, distance- and mag- nitude-independent roll-off spectral parameter, κeff = 0:03 s and (2) a size-dependent stress-drop parameter, which increases with moment magnitude, from ΔσBrune 4 MPa at Mw 3.5 to ΔσBrune 20 MPa at Mw 7.1. The set of parameters mentioned here may be used in order to predict the earthquake-induced ground motions expected from future earthquakes in the region surrounding Lake Van

    Studying the genetic structure of Quercus robur forest stands on anthropogenically transformed territories using introns of the β-tubulin gene

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    Based on the analysis of the intron polymorphism of β-tubulin genes, the genetic variability of old Quercus robur L. trees from “Holosiivsky” NPP was investigated. The genotyping of 55 old Q. robur trees was carried out; 40 polymorphic and one monomorphic (about 880 bp) TBR fragments were found. High frequency (70–90%) of occurrence of fragments with an approximate molecular weight of 275, 490, 500, and 1110 bp was observed.The genetic polymorphism of old Q. robur trees was assessed as quite high: РІС is 0.22 – 0.39, the effective number of alleles per locus was 1.174–1.268. The Shannon information index was in the range of 0.204–0.269.The geographical differentiation of the genetic structure of centuries-old oak trees from “Holosiivsky” NPP was not pronounced. The share of inter-selection genetic variability (AMOVA) accounts for about 6% of genetic variability, and the geographic component – about 1%. Around 93% of genetic variability is concentrated on the individual level. Using the ТВР method, we found that Q. robur forest stands do not have a stabilized genetic and visible spatial structure, but at the same time they possess a sufficiently large genetic diversity. The absence of a spatial genetic structure may indicate the artificial origin of Q. robur trees from different seed materials, and also that a small number of the plants have survived to this time. In this case, the main influence on the structure of oak stands in “Holosiivsky” NPP was from anthropogenic factors, both in the form of cutting down trees and, possibly, the introduction of alien seed material

    Assessment of Colobanthus quitensis genetic polymorphism from the Argentine Islands region (maritime Antarctic) by actin, α- and γ-tubulin gene intron analysis

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    Colobanthus quitensis is one of the two angiosperm plant species commonly spread in the Antarctic. The species has been extensively analyzed at morphological, anatomical and physiological levels, but information regarding its genetic vari-ability remains limited. The aim of the study was to identify molecular genetic differences between C. quitensis populations in one of the Antarctic localities, the Argentine Islands region by estimating the intron length polymorphism of actin, α- and γ-tubulin genes. Samples of C. quitensis from different Antarctic natural populations were collected during the season of the 24th and previous Ukrainian Antarctic expeditions. Total DNA was isolated using the QIAGEN DNeasy Plant Mini Kit. The polymerase chain reaction was carried out with our own degenerate primers. The resulting amplicons were separated and visualized using polyacrylamide gel electrophoresis followed by silver nitrate staining. Molecular genetic analysis of natural populations of C. quitensis was performed using three DNA-marker systems based on the detection of intron length polymor-phism of actin, α- and γ-tubulin genes. A low level of genetic polymorphism of C. quitensis in the studied region by these types of markers was established. By assessing the intron length polymorphism of actin genes of the studied C. quitensis populations it was possible to establish that the populations of Skua Island had unique amplicons characteristic only for this location. This indicates the possibility of further use of the analysis of intron length polymorphism of actin genes for the study of the molecu-lar genetic diversity of the Antarctic pearlwort. At the same time, the results of analysis of the intron length polymorphism of α- and γ-tubulin genes induce selection of more specific primers, taking into account the structure of the C. quitensis genome. C. quitensis in the study region has a low level of genetic variability in intron length polymorphism of actin, α- and γ-tubulin genes. Overall, the results indicate that DNA markers based on gene structure analysis of highly conserved cytoskeletal pro-teins, namely, actin, α- and γ-tubulin, as additional sources of information, can be used for molecular genetic analysis of C. quitensis populations in the Antarctic

    Gas and seismicity within the Istanbul seismic gap

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    Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain

    Determinants of Theory of Mind performance in Alzheimer’s disease: A data-mining study

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    Whether theory of mind (ToM) is preserved in Alzheimer’s disease (AD) remains a controversial subject. Recent studies have showed that performance on some ToM tests might be altered in AD, though to a lesser extent than in behavioural-variant Frontotemporal Dementia (bvFTD). It is however, unclear if this reflects a genuine impairment of ToM or a deficit secondary to the general cognitive decline observed in AD. Aiming to investigate the cognitive determinants of ToM performance in AD, a data-mining study was conducted in 29 AD patients then replicated in an independent age-matched group of 19 AD patients to perform an independent replication of the results. 44 bvFTD patients were included as a comparison group. All patients had an extensive neuropsychological examination. Hierarchical clustering analyses showed that ToM performance clustered with measures of executive functioning in AD. ToM performance was also specifically correlated with the executive component extracted from a principal component analysis. In a final step, automated linear modelling conducted to determine the predictors of ToM performance showed that 48.8% of ToM performance was significantly predicted by executive measures. Similar findings across analyses were observed in the independent group of AD patients, thereby replicating our results. Conversely, ToM impairments in bvFTD appeared independent of other cognitive impairments. These results suggest that difficulties of AD patients on ToM tests do not reflect a genuine ToM deficit, rather mediated by general (and particularly executive) cognitive decline. They also suggest that executive functioning has a key role in mental state attribution, which support interacting models of ToM functioning. Finally, our study highlights the relevancy of data-mining statistical approaches in clinical and cognitive neurosciences
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