44 research outputs found
Diffusive spin transport
Information to be stored and transported requires physical carriers. The
quantum bit of information (qubit) can for instance be realised as the spin 1/2
degree of freedom of a massive particle like an electron or as the spin 1
polarisation of a massless photon. In this lecture, I first use irreducible
representations of the rotation group to characterise the spin dynamics in a
least redundant manner. Specifically, I describe the decoherence dynamics of an
arbitrary spin S coupled to a randomly fluctuating magnetic field in the
Liouville space formalism. Secondly, I discuss the diffusive dynamics of the
particle's position in space due to the presence of randomly placed impurities.
Combining these two dynamics yields a coherent, unified picture of diffusive
spin transport, as applicable to mesoscopic electronic devices or photons
propagating in cold atomic clouds.Comment: Lecture notes, published in A. Buchleitner, C. Viviescas, and M.
Tiersch (Eds.), "Entanglement and Decoherence. Foundations and Modern
Trends", Lecture Notes in Physics 768, Springer, Berlin (2009
Quantizing N=2 Multicenter Solutions
N=2 supergravity in four dimensions, or equivalently N=1 supergravity in five
dimensions, has an interesting set of BPS solutions that each correspond to a
number of charged centers. This set contains black holes, black rings and their
bound states, as well as many smooth solutions. Moduli spaces of such solutions
carry a natural symplectic form which we determine, and which allows us to
study their quantization. By counting the resulting wavefunctions we come to an
independent derivation of some of the wall-crossing formulae. Knowledge of the
explicit form of these wavefunctions allows us to find quantum resolutions to
some apparent classical paradoxes such as solutions with barely bound centers
and those with an infinitely deep throat. We show that quantum effects seem to
cap off the throat at a finite depth and we give an estimate for the
corresponding mass gap in the dual CFT. This is an interesting example of a
system where quantum effects cannot be neglected at macroscopic scales even
though the curvature is everywhere small.Comment: 49 pages + appendice
Truncating SRCAP variants outside the Floating-Harbor syndrome locus cause a distinct neurodevelopmental disorder with a specific DNA methylation signature
Truncating variants in exons 33 and 34 of the SNF2-related CREBBP activator protein (SRCAP) gene cause the neurodevelopmental disorder (NDD) Floating-Harbor syndrome (FLHS), characterized by short stature, speech delay, and facial dysmorphism. Here, we present a cohort of 33 individuals with clinical features distinct from FLHS and truncating (mostly de novo) SRCAP variants either proximal (n = 28) or distal (n = 5) to the FLHS locus. Detailed clinical characterization of the proximal SRCAP individuals identified shared characteristics: developmental delay with or without intellectual disability, behavioral and psychiatric problems, non-specific facial features, musculoskeletal issues, and hypotonia. Because FLHS is known to be associated with a unique set of DNA methylation (DNAm) changes in blood, a DNAm signature, we investigated whether there was a distinct signature associated with our affected individuals. A machine-learning model, based on the FLHS DNAm signature, negatively classified all our tested subjects. Comparing proximal variants with typically developing controls, we identified a DNAm signature distinct from the FLHS signature. Based on the DNAm and clinical data, we refer to the condition as "non-FLHS SRCAP-related NDD.'' All five distal variants classified negatively using the FLHS DNAm model while two classified positively using the proximal model. This suggests divergent pathogenicity of these variants, though clinically the distal group presented with NDD, similar to the proximal SRCAP group. In summary, for SRCAP, there is a clear relationship between variant location, DNAm profile, and clinical phenotype. These results highlight the power of combined epigenetic, molecular, and clinical studies to identify and characterize genotype-epigenotype-phenotype correlations.Genetics of disease, diagnosis and treatmen
Pathogenic Germline Variants in 10,389 Adult Cancers
We conducted the largest investigation of predisposition variants in cancer to date, discovering 853 pathogenic or likely pathogenic variants in 8% of 10,389 cases from 33 cancer types. Twenty-one genes showed single or cross-cancer associations, including novel associations of SDHA in melanoma and PALB2 in stomach adenocarcinoma. The 659 predisposition variants and 18 additional large deletions in tumor suppressors, including ATM, BRCA1, and NF1, showed low gene expression and frequent (43%) loss of heterozygosity or biallelic two-hit events. We also discovered 33 such variants in oncogenes, including missenses in MET, RET, and PTPN11 associated with high gene expression. We nominated 47 additional predisposition variants from prioritized VUSs supported by multiple evidences involving case-control frequency, loss of heterozygosity, expression effect, and co-localization with mutations and modified residues. Our integrative approach links rare predisposition variants to functional consequences, informing future guidelines of variant classification and germline genetic testing in cancer. A pan-cancer analysis identifies hundreds of predisposing germline variants
Data from: Immune response increases predation risk
Why do individuals have an imperfect immune system? Most studies suggest trade-offs associated with immunity and metabolism, and neglect ecological factors, such as predation. We provide one of the first experimental studies demonstrating a context-dependent survival cost to immune activation. In the presence of a predator, immune-challenged male field crickets showed significantly lower survival than controls, whilst there was no difference in a predator-free environment. Immune-challenged males spent more time outside their burrows and reacted slower to a simulated predator attack. We conclude that some costs of immunity are expressed via increased susceptibility to predation, indicating the importance of integrating the ecological context when investigating optimal investment in immunity
Otti.etal.Behavior data
Data for behavior analysis Table S2 and Figure 2c. We would appreciate to be informed about any reuse of our data ([email protected])
Otti.etal.Survival data
Survival data for Figure 2b We would appreciate to be informed about any reuse of our data ([email protected])
Predator avoidance trait data
Data for predator avoidance traits analysis and Figure 3. We would appreciate to be informed about any reuse of our data ([email protected])
Health effects of sulfur-related environmental air pollution. V. Lung structure.
The lungs of 8 male beagle dogs were examined morphologically and morphometrically after exposure for 13 mo to a respirable sulfur(IV) aerosol at a mass concentration of 1.53 mg m(-3) (16.5 h/day), and to an acidic sulfate aerosol carrying 15.2 micromol m(-3) hydrogen ions into the lungs (6 h/day). An additional eight dogs served as unexposed controls. Standard morphometric analyses of both the surface epithelia of the conducting airways and the alveolar region were performed. These analyses showed no difference between the exposure group and control group. However, there was a tendency to an increase in the volume density of bronchial glands in the exposure group. Five of eight exposed animals showed thickened ridges (knob-like structures) at the entrance to alveoli in the alveolar duct and alveolar sac. Transmission electron microscopy revealed that the thickening was mainly due to type II cell proliferation. As the previous experiment using sulfite aerosol only showed no alterations in the proximal alveolar regions, the changes observed may be considered as effects of acidic sulfate aerosol alone or in combination with sulfite. These findings suggest that sulfur aerosols have the potential to induce epithelial alterations in the proximal alveolar region, which is a primary target for air pollutants