1,114 research outputs found
Behavioral origin of sound-evoked activity in mouse visual cortex
Sensory cortices can be affected by stimuli of multiple modalities and are thus increasingly thought to be multisensory. For instance, primary visual cortex (V1) is influenced not only by images but also by sounds. Here we show that the activity evoked by sounds in V1, measured with Neuropixels probes, is stereotyped across neurons and even across mice. It is independent of projections from auditory cortex and resembles activity evoked in the hippocampal formation, which receives little direct auditory input. Its low-dimensional nature starkly contrasts the high-dimensional code that V1 uses to represent images. Furthermore, this sound-evoked activity can be precisely predicted by small body movements that are elicited by each sound and are stereotyped across trials and mice. Thus, neural activity that is apparently multisensory may simply arise from low-dimensional signals associated with internal state and behavior
Timing of crystallization of the lunar magma ocean constrained by the oldest zircon
The Moon is thought to have formed through the consolidationof debris from the collision of a Mars-sized body with the Earthmore than 4,500 million years ago. The primitive Moon wascovered with a thick layer of melt known as the lunar magmaocean1, the crystallization of which resulted in the Moon?ssurface as it is observed today. There is considerable debate,however, over the precise timing and duration of the processof magma ocean crystallization. Here we date a zircon fromlunar breccias to an age of 4,4176 million years. This dateprovides a precise younger age limit for the solidification ofthe lunar magma ocean. We propose a model that suggestsan exponential rate of lunar crystallization, based on acombination of this oldest known lunar zircon and the age of theMoon-forming giant impact. We conclude that the formationof the Moon?s anorthositic crust followed the solidification of80?85% of the original melt, within about 100 million years ofthe collision. The existence of younger zircons2 is indicative ofthe continued solidification of a small percentage of melt for anextra 200?400 million years
Operational Challenges in Diagnosing Multi-Drug Resistant TB and Initiating Treatment in Andhra Pradesh, India
Revised National TB Control Programme (RNTCP), Andhra Pradesh, India. There is limited information on whether MDR-TB suspects are identified, undergo diagnostic assessment and are initiated on treatment according to the programme guidelines.To assess i) using the programme definition, the number and proportion of MDR-TB suspects in a large cohort of TB patients on first-line treatment under RNTCP ii) the proportion of these MDR-TB suspects who underwent diagnosis for MDR-TB and iii) the number and proportion of those diagnosed as MDR-TB who were successfully initiated on treatment.A retrospective cohort analysis, by reviewing RNTCP records and reports, was conducted in four districts of Andhra Pradesh, India, among patients registered for first line treatment during October 2008 to December 2009.Among 23,999 TB patients registered for treatment there were 559 (2%) MDR-TB suspects (according to programme definition) of which 307 (55%) underwent diagnosis and amongst these 169 (55%) were found to be MDR-TB. Of the MDR-TB patients, 112 (66%) were successfully initiated on treatment. Amongst those eligible for MDR-TB services, significant proportions are lost during the diagnostic and treatment initiation pathway due to a variety of operational challenges. The programme needs to urgently address these challenges for effective delivery and utilisation of the MDR-TB services
Charged Scalar-Tensor Boson Stars: Equilibrium, Stability and Evolution
We study charged boson stars in scalar-tensor (ST) gravitational theories. We
analyse the weak field limit of the solutions and analytically show that there
is a maximum charge to mass ratio for the bosons above which the weak field
solutions are not stable. This charge limit can be greater than the GR limit
for a wide class of ST theories. We numerically investigate strong field
solutions in both the Brans Dicke and power law ST theories. We find that the
charge limit decreases with increasing central boson density. We discuss the
gravitational evolution of charged and uncharged boson stars in a cosmological
setting and show how, at any point in its evolution, the physical properties of
the star may be calculated by a rescaling of a solution whose asymptotic value
of the scalar field is equal to its initial asymptotic value. We focus on
evolution in which the particle number of the star is conserved and we find
that the energy and central density of the star decreases as the cosmological
time increases. We also analyse the appearance of the scalarization phenomenon
recently discovered for neutron stars configurations and, finally, we give a
short discussion on how making the correct choice of mass influences the
argument over which conformal frame, the Einstein frame or the Jordan frame, is
physical.Comment: RevTeX, 27 pages, 9 postscript figures. Minor revisions and updated
references. Accepted for publication in Phys. Rev.
The atmospheric parameters and spectral interpolator for the stars of MILES
Context. Empirical libraries of stellar spectra are used for stellar
classification and synthesis of stellar populations. MILES is a medium
spectral-resolution library in the optical domain covering a wide range of
temperatures, surface gravities and metallicities. Aims. We re-determine the
atmospheric parameters of these stars in order to improve the homogeneity and
accuracy. We build an interpolating function that returns a spectrum as a
function of the three atmospheric parameters, and finally, we characterize the
precision of the wavelength calibration and stability of the spectral
resolution. Methods. We use the ULySS program with the ELODIE library as a
reference and compare the results with literature compilations. Results. We
obtain precisions of 60 K, 0.13 and 0.05 dex respectively for Teff, log g and
[Fe/H] for the FGK stars. For the M stars, the mean errors are 38 K, 0.26 and
0.12 dex, and for the OBA 3.5%, 0.17 and 0.13 dex. We construct an interpolator
that we test against the MILES stars themselves. We test it also by measuring
the atmospheric parameters of the CFLIB stars with MILES as reference and find
it to be more reliable than the ELODIE interpolator for the evolved hot stars,
like in particular those of the blue horizontal branch.Comment: A&A accepted, 29 pages, 6 figure
Phenotyping of lymphoproliferative tumours generated in xenografts of non-small cell lung cancer
Background: Patient-derived xenograft (PDX) models involve the engraftment of tumour tissue in immunocompromised mice and represent an important pre-clinical oncology research method. A limitation of non-small cell lung cancer (NSCLC) PDX model derivation in NOD-scid IL2Rgammanull (NSG) mice is that a subset of initial engraftments are of lymphocytic, rather than tumour origin. / Methods: The immunophenotype of lymphoproliferations arising in the lung TRACERx PDX pipeline were characterised. To present the histology data herein, we developed a Python-based tool for generating patient-level pathology overview figures from whole-slide image files; PATHOverview is available on GitHub (https://github.com/EpiCENTR-Lab/PATHOverview). / Results: Lymphoproliferations occurred in 17.8% of lung adenocarcinoma and 10% of lung squamous cell carcinoma transplantations, despite none of these patients having a prior or subsequent clinical history of lymphoproliferative disease. Lymphoproliferations were predominantly human CD20+ B cells and had the immunophenotype expected for post-transplantation diffuse large B cell lymphoma with plasma cell features. All lymphoproliferations expressed Epstein-Barr-encoded RNAs (EBER). Analysis of immunoglobulin light chain gene rearrangements in three tumours where multiple tumour regions had resulted in lymphoproliferations suggested that each had independent clonal origins. / Discussion: Overall, these data suggest that B cell clones with lymphoproliferative potential are present within primary NSCLC tumours, and that these are under continuous immune surveillance. Since these cells can be expanded following transplantation into NSG mice, our data highlight the value of quality control measures to identify lymphoproliferations within xenograft pipelines and support the incorporation of strategies to minimise lymphoproliferations during the early stages of xenograft establishment pipelines
Metabotyping of docosahexaenoic acid - Treated alzheimer's disease cell model
10.1371/journal.pone.0090123PLoS ONE92-POLN
Concurrence of Danish Dementia and Cataract: Insights from the Interactions of Dementia Associated Peptides with Eye Lens α-Crystallin
Familial Danish Dementia (FDD) is an autosomal disease, which is distinguished by gradual loss of vision, deafness, progressive ataxia and dementia. Cataract is the first manifestation of the disease. In this article, we demonstrate a specific correlation between the poisoning of the chaperone activity of the rat eye lens α-crystallins, loss of lens transparency in organ culture by the pathogenic form of the Danish dementia peptide, i.e. the reduced Danish dementia peptide (redADan peptide), by a combination of ex vivo, in vitro, biophysical and biochemical techniques. The interaction of redADan peptide and lens crystallins are very specific when compared with another chaperone, HSP-70, underscoring the specificity of the pathogenic form of Danish dementia peptide, redADan, for the early onset of cataract in this disease
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