222 research outputs found
Neutron Stars Mass-Radius relations analysis in the Quintessence scenario
In this paper, we explore the effects of General Relativity modification on
the Mass-Radius relations of Neutron Stars induced by the presence of the
Quintessence field. We consider, in particular, the Kiselev model, according to
which the Quintessence field, being present in the entire Universe, might also
be present around massive objects. Considering the Equation of State (EoS) for
Baryonic matter BSk22 derived by A. Y. Potekhin et al., we infer the upper
limit for NS masses in the presence of Quintessence. The presence of
Quintessence generates a peculiar effect for which the Mass-Radius relation is
unvaried and therefore the presence of Quintessence is indistinguishable from
ordinary matter, at least for the Kiselev model studied in this paper.Comment: 5 pages, 2 figure
Influence of electromagnetic interferences on the gravimetric sensitivity of surface acoustic waveguides
Surface acoustic waveguides are increasing in interest for (bio)chemical
detection. The surface mass modification leads to measurable changes in the
propagation properties of the waveguide. Among a wide variety of waveguides,
Love mode has been investigated because of its high gravimetric sensitivity.
The acoustic signal launched and detected in the waveguide by electrical
transducers is accompanied by an electromagnetic wave; the interaction of the
two signals, easily enhanced by the open structure of the sensor, creates
interference patterns in the transfer function of the sensor. The influence of
these interferences on the gravimetric sensitivity is presented, whereby the
structure of the entire sensor is modelled. We show that electromagnetic
interferences generate an error in the experimental value of the sensitivity.
This error is different for the open and the closed loop configurations of the
sensor. The theoretical approach is completed by the experimentation of an
actual Love mode sensor operated under liquid in open loop configuration. The
experiment indicates that the interaction depends on the frequency and the mass
modifications.Comment: 28 pages, 8 figure
Simultaneous surface acoustic wave and surface plasmon resonance measurements: electrodeposition and biological interactions monitoring
We present results from an instrument combining surface acoustic wave (SAW)
propagation and surface plasmon resonance (SPR) measurements. The objective is
to use two independent methods, the former based on adsorbed mass change
measurements and the latter on surface dielectric properties variations, to
identify physical properties of protein layers, and more specifically their
water content. We display mass sensitivity calibration curves using
electrodeposition of copper leading to a sensitivity in liquid of 150
for the Love mode device used here, and the application to monitoring
biological processes. The extraction of protein layer thickness and protein to
water content ratio is also presented for S-layer proteins under investigation.
We obtain respectively 4.70.7 nm and 7515%.Comment: 13 pages, 4 figure
Identification of the novel KI polyomavirus in paranasal and lung tissues
KI is a novel polyomavirus identified in the respiratory secretions of children with acute respiratory symptoms. Whether this reflects a causal role of the virus in the human respiratory disease remains to be established. To investigate the presence of KIV in the respiratory tissue, we examined 20 fresh lung cancer specimens and surrounding normal tissue along with one paranasal and one lung biopsy from two transplanted children. KIV-VP1 gene was detected in 9/20 lung cancer patients and 2/2 transplanted patients. However, amplification of the sequence coding for the C-terminal part of the early region of KIV performed on the 11 positive cases was successful only in two malignant lung tissues, one surrounding normal tissue, and 1/2 biopsies tested. Phylogenetic analysis performed on the early region of KIV (including the four Italian isolates), BKV and JCV revealed the presence of three distinct clades. Within the KIV clade two sub-clades were observed. A sub-clade A containing the four Italian strains, and a sub-clade B comprising the Swedish and Australian isolates. Interestingly, the two Italian strains identified in normal tissue clustered together, whereas those detected in malignant tissue fell outside this cluster. In vitro studies are needed to investigate the transforming potential of KIV strains. J. Med. Virol. 81:558-561,2009. (C) 2009 Wiley-Liss, Inc
Characterization of low pathogenic H5 subtype influenza viruses from Eurasia: Implications for the origin of highly pathogenic H5N1 viruses
Oral Presentations - Genetic and Antigenic EvolutionHighly pathogenic avian influenza (HPAI) H5N1 viruses are now endemic in many Asian countries. The immediate precursor of these HPAI viruses was recognized as A/Goose/Guangdong/1/96 (Gs/Gd)-like H5N1 HPAI viruses first detected in Guangdong in 1996. However, precursors of the Gs/GD-like viruses and their subsequent reassortants have not been fully determined. Here we characterize low pathogenic avian influenza (LPAI) H5 subtype viruses isolated from poultry and migratory birds in southern China and Europe from the 1970s to the 2000s. Phylogenetic analyses revealed that Gs/GD-like virus was likely derived from an LPAI H5 virus in migratory birds. However, its variants arose from multiple reassortments between Gs/GD-like virus and viruses from migratory birds, or with those Eurasian viruses isolated in the 1970s. It is of note that unlike HPAI H5N1 viruses, those recent LPAI H5 viruses have not become established in aquatic or terrestrial poultry. Phylogenetic analyses revealed the dynamic nature of the influenza gene pool in Eurasia with repeated transmissions between the eastern and western extremities of the continent. The data also shows reassortment between influenza viruses from domestic and migratory birds in this region that has contributed to the expanded diversity of the influenza gene pool among poultry in Eurasia ...postprin
Accounting for expert performance: the devil is in the details
The deliberate practice view has generated a great deal of scientific and popular interest in expert performance. At the same time, empirical evidence now indicates that deliberate practice, while certainly important, is not as important as Ericsson and colleagues have argued it is. In particular, we (Hambrick, Oswald, Altmann, Meinz, Gobet, & Campitelli, 2014) found that individual differences in accumulated amount of deliberate practice accounted for about one-third of the reliable variance in performance in chess and music, leaving the majority of the reliable variance unexplained and potentially explainable by other factors. Ericsson's (2014) defense of the deliberate practice view, though vigorous, is undercut by contradictions, oversights, and errors in his arguments and criticisms, several of which we describe here. We reiterate that the task now is to develop and rigorously test falsifiable theories of expert performance that take into account as many potentially relevant constructs as possible
A Novel Digital Digit-Symbol Substitution Test Measuring Processing Speed in Adults At Risk for Alzheimer Disease: Validation Study
Background: Assessing cognitive constructs affected by Alzheimer disease, such as processing speed (PS), is important to screen for potential disease and allow for early detection. Digital PS assessments have been developed to provide widespread, efficient cognitive testing, but all have been validated only based on the correlation between test scores. Best statistical practices dictate that concurrent validity should be assessed for agreement or equivalence rather than using correlation alone.
Objective: This study aimed to assess the concurrent validity of a novel digital PS assessment against a gold-standard measure of PS.
Methods: Adults aged 45-75 years (n=191) participated in this study. Participants completed the novel digital digit-symbol substitution test (DDSST) and the Repeatable Battery for the Assessment of Neuropsychological Status coding test (RBANS-C). The correlation between the test scores was determined using a Pearson product-moment correlation, and a difference in mean test scores between tests was checked for using a 2-tailed dependent samples t test. Data were analyzed for agreement between the 2 tests using Bland-Altman limits of agreement and equivalency using a two one-sided t tests (TOST) approach.
Results: A significant moderate, positive correlation was found between DDSST and RBANS-C scores (r=.577; P\u3c.001), and no difference in mean scores was detected between the tests (P=.93). Bias was nearly zero (0.04). Scores between the tests were found to display adequate agreement with 90% of score differences falling between –22.66 and 22.75 (90% limits of agreement=–22.91 to 22.99), and the scores were equivalent (P=.049).
Conclusions: Analyses indicate that the DDSST is a valid digital assessment of PS. The DDSST appears to be a suitable option for widespread, immediate, and efficient PS testing.
Trial Registration: ClinicalTrials.gov NCT04559789; https://clinicaltrials.gov/ct2/show/NCT0455978
Effective connectivity reveals strategy differences in an expert calculator
Mathematical reasoning is a core component of cognition and the study of experts defines the upper limits of human cognitive abilities, which is why we are fascinated by peak performers, such as chess masters and mental calculators. Here, we investigated the neural bases of calendrical skills, i.e. the ability to rapidly identify the weekday of a particular date, in a gifted mental calculator who does not fall in the autistic spectrum, using functional MRI. Graph-based mapping of effective connectivity, but not univariate analysis, revealed distinct anatomical location of “cortical hubs” supporting the processing of well-practiced close dates and less-practiced remote dates: the former engaged predominantly occipital and medial temporal areas, whereas the latter were associated mainly with prefrontal, orbitofrontal and anterior cingulate connectivity. These results point to the effect of extensive practice on the development of expertise and long term working memory, and demonstrate the role of frontal networks in supporting performance on less practiced calculations, which incur additional processing demands. Through the example of calendrical skills, our results demonstrate that the ability to perform complex calculations is initially supported by extensive attentional and strategic resources, which, as expertise develops, are gradually replaced by access to long term working memory for familiar material
Molecular analysis of avian H7 influenza viruses circulating in Eurasia in 1999-2005: detection of multiple reassortant virus genotypes.
Avian influenza infections by high and low pathogenicity H7 influenza viruses have caused several outbreaks in European poultry in recent years, also resulting in human infections. Although in some cases the source of H7 strains from domestic poultry was shown to be the viruses circulating in the wild bird reservoir, a thorough characterization of the entire genome of H7 viruses from both wild and domestic Eurasian birds, and their evolutionary relationships, has not been conducted. In our study, we have analysed low pathogenicity H7 influenza strains isolated from wild and domestic ducks in Italy and southern China and compared them with those from reared terrestrial poultry such as chicken and turkey. Phylogenetic analysis demonstrated that the H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated. A recent precursor in wild waterfowl was identified for most of the gene segments of terrestrial poultry viruses. Our data suggest that reassortment allows avian influenza viruses, in their natural reservoir, to increase their genetic diversity. In turn this might help avian influenza viruses colonize a wider range of hosts, including domestic poultry
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