4,039 research outputs found
Conservative and disruptive modes of adolescent change in human brain functional connectivity
Adolescent changes in human brain function are not entirely understood. Here, we used multiecho functional MRI (fMRI) to measure developmental change in functional connectivity (FC) of resting-state oscillations between pairs of 330 cortical regions and 16 subcortical regions in 298 healthy adolescents scanned 520 times. Participants were aged 14 to 26 y and were scanned on 1 to 3 occasions at least 6 mo apart. We found 2 distinct modes of age-related change in FC: “conservative” and “disruptive.” Conservative development was characteristic of primary cortex, which was strongly connected at 14 y and became even more connected in the period from 14 to 26 y. Disruptive development was characteristic of association cortex and subcortical regions, where connectivity was remodeled: connections that were weak at 14 y became stronger during adolescence, and connections that were strong at 14 y became weaker. These modes of development were quantified using the maturational index (MI), estimated as Spearman’s correlation between edgewise baseline FC (at 14 y, FC14) and adolescent change in FC (ΔFC14−26), at each region. Disruptive systems (with negative MI) were activated by social cognition and autobiographical memory tasks in prior fMRI data and significantly colocated with prior maps of aerobic glycolysis (AG), AG-related gene expression, postnatal cortical surface expansion, and adolescent shrinkage of cortical thickness. The presence of these 2 modes of development was robust to numerous sensitivity analyses. We conclude that human brain organization is disrupted during adolescence by remodeling of FC between association cortical and subcortical areas
An Instanton Picture O.P.E. <A^2> Condensate?
Gluon two- and three-point Green Functions computed in Landau gauge from the
lattice show the existence of power corrections to the purely perturbative
expressions, that can be explained through an Operator Product Expansion as the
influence of a non gauge invariant mass dimension two condensate. The
relationship of this condensate with topological properties of QCD, namely
instantons, will be studied, giving a first estimate of the contribution of
instantons to this condensate based in the direct lattice measure, after a
cooling process, of the instanton liquid properties.Comment: Lattice2002(topology) contribution, 3 pages, 2 figure
Electronic excitation spectra of cerium oxides: from ab initio dielectric response functions to Monte Carlo electron transport simulations
Nanomaterials made of the cerium oxides CeO and CeO have a broad
range of applications, from catalysts in automotive, industrial or energy
operations to promising materials to enhance hadrontherapy effectiveness in
oncological treatments. To elucidate the physico-chemical mechanisms involved
in these processes, it is of paramount importance to know the electronic
excitation spectra of these oxides, which are obtained here through
high-accuracy linear-response time-dependent density functional theory
calculations. In particular, the macroscopic dielectric response functions
of both bulk CeO and CeO are derived, which compare
remarkably well with the available experimental data. These results stress the
importance of appropriately accounting for local field effects to model the
dielectric function of metal oxides. Furthermore, we reckon the materials
energy loss functions \mbox{Im} (-1/\bar{\epsilon}), including the accurate
evaluation of the momentum transfer dispersion from first-principles. In this
respect, by using a Mermin-type parametrization we are able to model the
contribution of different electronic excitations to the dielectric loss
function. Finally, from the knowledge of the electron inelastic mean free path,
together with the elastic mean free path provided by the relativistic Mott
theory, we carry out statistical Monte Carlo (MC) charge transport simulations
to reproduce the major features of the reported experimental reflection
electron energy loss (REEL) spectra of cerium oxides. The good agreement with
REEL experimental data strongly supports our approach based on MC modelling
informed by ab initio calculated electronic excitation spectra in a broad range
of momentum and energy transfers.Comment: 21 pages, 19 figure
Solar Neutrinos Before and After KamLAND
We use the recently reported KamLAND measurements on oscillations of reactor
anti-neutrinos, together with the data of previously reported solar neutrino
experiments, to show that: (1) the total 8B neutrino flux emitted by the Sun is
1.00(1.0 \pm 0.06) of the standard solar model (BP00) predicted flux, (2) the
KamLAND measurements reduce the area of the globally allowed oscillation
regions that must be explored in model fitting by six orders of magnitude in
the Delta m^2-tan^2 theta plane, (3) LMA is now the unique oscillation solution
to a CL of 4.7sigma, (4) maximal mixing is disfavored at 3.1 sigma, (5)
active-sterile admixtures are constrained to sin^2 eta<0.13 at 1 sigma, (6) the
observed ^8B flux that is in the form of sterile neutrinos is
0.00^{+0.09}_{-0.00} (1 sigma), of the standard solar model (BP00) predicted
flux, and (7) non-standard solar models that were invented to completely avoid
solar neutrino oscillations are excluded by KamLAND plus solar at 7.9 sigma .
We also refine quantitative predictions for future 7Be and p-p solar neutrino
experiments.Comment: Published version, includes editorial improvement
A study of the pressure profiles near the first pumping aperture in a high pressure photoelectron spectrometer
Next-gen sequencing of multi-drug resistant Acinetobacter baumannii to determine antibiotic resistance genotypes
Diagnostic procedures for non-small-cell lung cancer (NSCLC): recommendations of the European Expert Group
Background There is currently no Europe-wide consensus on the appropriate preanalytical measures and workflow to optimise procedures for tissue-based molecular testing of non-small-cell lung cancer (NSCLC). To address this, a group of lung cancer experts (see list of authors) convened to discuss and propose standard operating procedures (SOPs) for NSCLC. Methods Based on earlier meetings and scientific expertise on lung cancer, a multidisciplinary group meeting was aligned. The aim was to include all relevant aspects concerning NSCLC diagnosis. After careful consideration, the following topics were selected and each was reviewed by the experts: surgical resection and sampling; biopsy procedures for analysis; preanalytical and other variables affecting quality of tissue; tissue conservation; testing procedures for epidermal growth factor receptor, anaplastic lymphoma kinase and ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) in lung tissue and cytological specimens; as well as standardised reporting and quality control (QC). Finally, an optimal workflow was described. Results Suggested optimal procedures and workflows are discussed in detail. The broad consensus was that the complex workflow presented can only be executed effectively by an interdisciplinary approach using a well-trained team. Conclusions To optimise diagnosis and treatment of patients with NSCLC, it is essential to establish SOPs that are adaptable to the local situation. In addition, a continuous QC system and a local multidisciplinary tumour-type-oriented board are essential
Human Computation and Convergence
Humans are the most effective integrators and producers of information,
directly and through the use of information-processing inventions. As these
inventions become increasingly sophisticated, the substantive role of humans in
processing information will tend toward capabilities that derive from our most
complex cognitive processes, e.g., abstraction, creativity, and applied world
knowledge. Through the advancement of human computation - methods that leverage
the respective strengths of humans and machines in distributed
information-processing systems - formerly discrete processes will combine
synergistically into increasingly integrated and complex information processing
systems. These new, collective systems will exhibit an unprecedented degree of
predictive accuracy in modeling physical and techno-social processes, and may
ultimately coalesce into a single unified predictive organism, with the
capacity to address societies most wicked problems and achieve planetary
homeostasis.Comment: Pre-publication draft of chapter. 24 pages, 3 figures; added
references to page 1 and 3, and corrected typ
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