4,799 research outputs found
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Direct evidence for thymic function in adult humans.
The understanding of human thymic function and evaluation of its contribution to T cell homeostasis are matters of great importance. Here we report the development of a novel assay to quantitate the frequency and diversity of recent thymic emigrants (RTEs) in the peripheral blood of humans. Such cells were defined by the presence of T cell receptor (TCR) rearrangement deletion circles (DCs), episomal byproducts of TCR-beta V(D)J rearrangement. DCs were detected in T cells in the thymus, cord blood, and adult peripheral blood. In the peripheral blood of adults aged 22 to 76 years, their frequency was highest in the CD4(+)CD45RA(+) CD62L(+) subpopulation of naive T cells. TCR DCs were also observed in other subpopulations of peripheral blood T cells, including those with the CD4(+)CD45RO(-)CD62L(+) and CD4(+)CD45RO(+)CD62L(+) phenotypes. RTEs were observed to have more than one Vbeta rearrangement, suggesting that replenishment of the repertoire in the adult is at least oligoclonal. These results demonstrate that the normal adult thymus continues to contribute, even in older individuals, a diverse set of new T cells to the peripheral circulation
Secure pseudo-random linear binary sequences generators based on arithmetic polynoms
We present a new approach to constructing of pseudo-random binary sequences
(PRS) generators for the purpose of cryptographic data protection, secured from
the perpetrator's attacks, caused by generation of masses of hardware errors
and faults. The new method is based on use of linear polynomial arithmetic for
the realization of systems of boolean characteristic functions of PRS'
generators. "Arithmetizatio" of systems of logic formulas has allowed to apply
mathematical apparatus of residue systems for multisequencing of the process of
PRS generation and organizing control of computing errors, caused by hardware
faults. This has guaranteed high security of PRS generator's functioning and,
consequently, security of tools for cryptographic data protection based on
those PRSs
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Symptoms predicting psychosocial impairment in bulimia nervosa
Purpose
The current study aimed to determine which particular eating disorder (ED) symptoms and related features, such as BMI and psychological distress, uniquely predict impairment in bulimia nervosa (BN).
Methods
Two hundred and twenty-two adults with BN completed questionnaires assessing ED symptoms, general psychological distress, and psychosocial impairment. Regression analyses were used to determine predictors which account for variance in impairment.
Results
Four variables emerged as significant predictors of psychosocial impairment: concerns with eating; concerns with weight and shape; dietary restraint; and general psychological distress.
Conclusions
Findings support previous work highlighting the importance of weight and shape concerns in determining ED-related impairment. Other ED symptoms, notably dietary restraint and concerns with eating, were also significant predictors as was psychological distress. Results suggest that cognitive aspects of EDs, in addition to psychological distress, may be more important determinants of impairment than behavioural symptoms, such as binge eating or purging
2D non-LTE modelling of a filament observed in the H_alpha line with the DST/IBIS spectropolarimeter
We study a fragment of a large quiescent filament observed on May 29, 2017 by the Interferometric BIdimensional Spectropolarimeter (IBIS) mounted at the Dunn Solar Telescope. We focus on its quiescent stage prior to its eruption. We analyse the spectral observations obtained in the H line to derive the thermodynamic properties of the plasma of the observed fragment of the filament. We used a 2D filament model employing radiative transfer computations under conditions that depart from the local thermodynamic equilibrium. We employed a forward modelling technique in which we used the 2D model to producesynthetic H_alpha line profiles that we compared with the observations. We then found the set of model input parameters, which produces synthetic spectra with the best agreement with observations. Our analysis shows that one part of the observed fragment of the filament is cooler, denser, and more dynamic than its other part that is hotter, less dense, and more quiescent. The derived temperatures in the first part range from 6,000 K to 10,000$ K and in the latter part from 11,000 K to 14,000 K. The gas pressure is 0.2-0.4 dyn/cm}^{2} in the first part and around 0.15 dyn/cm}^{2} in the latter part. The more dynamic nature of the first part is characterised by the line-of-sight velocities with absolute values of 6-7 km/s and microturbulent velocities of 8-9 km/s. On the other hand, the latter part exhibits line-of-sight velocities with absolute values 0-2.5 km/s and microturbulent velocities of 4-6 km/s
Effect of microsegregation and heat treatment on localised γ and γ’ compositions in single crystal Ni-based superalloys
The present work investigates the impact of residual segregation on the underlying microstructure of a 3rd generation single crystal, nickel-based superalloy to understand potential variation in mechanical behaviour between dendrite cores and interdendritic regions. Despite the applied heat-treatments, chemical variation between dendrite cores and interdendritic regions persisted particularly for elements Re, Nb and Ta. Atom probe tomography (APT) was utilized for its nanoscale capability to map site-specific chemical changes in the γ matrix, γ’ precipitates and across the γ/γ’ interface. Greater interfacial segregation of Re, matched by a corresponding depletion of Ni were observed within dendrite cores, with the extent found to increase following heat treatment. Differences in lattice parameters between dendrite cores and interdendritic regions were identified, with larger lattice misfits associated with interdendritic regions
The age of anxiety? It depends where you look: changes in STAI trait anxiety, 1970–2010
Purpose
Population-level surveys suggest that anxiety has been increasing in several nations, including the USA and UK. We sought to verify the apparent anxiety increases by looking for systematic changes in mean anxiety questionnaire scores from research publications.
Methods
We analyzed all available mean State–Trait Anxiety Inventory scores published between 1970 and 2010. We collected 1703 samples, representing more than 205,000 participants from 57 nations.
Results
Results showed a significant anxiety increase worldwide, but the pattern was less clear in many individual nations. Our analyses suggest that any increase in anxiety in the USA and Canada may be limited to students, anxiety has decreased in the UK, and has remained stable in Australia.
Conclusions
Although anxiety may have increased worldwide, it might not be increasing as dramatically as previously thought, except in specific populations, such as North American students. Our results seem to contradict survey results from the USA and UK in particular. We do not claim that our results are more reliable than those of large population surveys. However, we do suggest that mental health surveys and other governmental sources of disorder prevalence data may be partially biased by changing attitudes toward mental health: if respondents are more aware and less ashamed of their anxiety, they are more likely to report it to survey takers. Analyses such as ours provide a useful means of double-checking apparent trends in large population surveys
Assessing availability and greenhouse gas emissions of lignocellulosic biomass feedstock supply – case study for a catchment in England
© 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.Feedstocks from lignocellulosic biomass (LCB) include crop residues and dedicated per¬ennial biomass crops. The latter are often considered superior in terms of climate change mitigation potential. Uncertainty remains over their availability as feedstocks for biomass provision and the net greenhouse gas emissions (GHG) during crop production. Our objective was to assess the optimal land allocation to wheat and Miscanthus in a specific case study located in England, to increase bio¬mass availability, improve the carbon balance (and reduce the consequent GHG emissions), and mini¬mally constrain grain production losses from wheat. Using soil and climate variables for a catchment in east England, biomass yields and direct nitrogen emissions were simulated with validated process-based models. A ‘Field to up-stream factory gate’ life-cycle assessment was conducted to estimate indirect management-related GHG emissions. Results show that feedstock supply from wheat straw can be supplemented beneficially with LCB from Miscanthus grown on selected low-quality soils. In our study, 8% of the less productive arable land area was dedicated to Miscanthus, increasing total LCB provision by about 150%, with a 52% reduction in GHG emission per ton LCB delivered and only a minor effect on wheat grain production (−3%). In conclusion, even without considering the likely carbon sequestration in impoverished soils, agriculture should embrace the opportunities to provide the bioeconomy with LCB from dedicated, perennial crops.Peer reviewe
Which game narratives do adolescents of different gameplay and sociodemographic backgrounds prefer? a mixed-methods analysis
OBJECTIVE: The aim of this study was to investigate which narrative elements of digital game narratives are preferred by the general adolescent population, and to examine associations with gender, socioeconomic status (SES), and gameplay frequency. Further, the study aims to discuss how results can be translated to serious digital games.
MATERIALS AND METHODS: Adolescents were recruited through school to complete a survey on narrative preferences in digital games. The survey included questions on sociodemographic information, frequency of gameplay, and an open-ended question on what could be an appealing narrative for them. Data were analyzed in a mixed-methods approach, using thematic analysis and chi-square analyses to determine narrative preferences and the associations between game narrative elements and player characteristics (gender, SES, and frequency of gameplay).
RESULTS: The sample consisted of 446 adolescents (12-15 years old) who described 30 narrative subthemes. Preferences included human characters as protagonists; nonhuman characters only as antagonists; realistic settings, such as public places or cities; and a strong conflict surrounding crime, catastrophe, or war. Girls more often than boys defined characters by their age, included avatars, located the narrative in private places, developed profession-related skills, and included a positive atmosphere. Adolescents of nonacademic education more often than adolescents of academic education defined characters by criminal actions. Infrequent players more often included human characters defined by their age than frequent players. After performing a Bonferroni correction, narrative preferences for several gender differences remained.
CONCLUSION: Different narrative elements related to subgroups of adolescents by gender, SES, and frequency of gameplay. Customization of narratives in serious digital health games should be warranted for boys and girls; yet, further research is needed to specify how to address girls in particular
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