300 research outputs found
Isotropic magnetometry with simultaneous excitation of orientation and alignment CPT resonances
Atomic magnetometers have very high absolute precision and sensitivity to
magnetic fields but suffer from a fundamental problem: the vectorial or
tensorial interaction of light with atoms leads to "dead zones", certain
orientations of magnetic field where the magnetometer loses its sensitivity. We
demonstrate a simple polarization modulation scheme that simultaneously creates
coherent population trapping (CPT) in orientation and alignment, thereby
eliminating dead zones. Using Rb in a 10 Torr buffer gas cell we measure
narrow, high-contrast CPT transparency peaks in all orientations and also show
absence of systematic effects associated with non-linear Zeeman splitting.Comment: 4 pages, 4 figure
Ionospheric Currents and F-Region Plasma Boundaries Near the Dayside Cusp
Observational evidence of the location of a dayside highâlatitude ionospheric current (DPY current) with respect to the different regimes of the highâlatitude magnetosphere is obtained by analyzing data from the magnetometer chain along the west coast of Greenland in conjunction with simultaneous measurements from the newly established incoherentâscatter radar facility at Sondre Stromfjord. The latitudinal location of the DPY current is compared with the location of the maximum Fâregion electron temperature and with the location of the plasma convection reversal from sunward to antisunward. The maximum in the Fâregion electron temperature roughly coincides with the velocity reversal boundary, while the DPY current is always located more poleward, penetrating deep into the polar cap. When UT variations are examined, a correlation of 70 to 80 percent is found between the three locations
Critical component of the interplanetary magnetic field responsible for large geomagnetic effects in the polar cap
An observed influence is studied of the interplanetary magnetic sector structure on the geomagnetic variations in the polar cap which appears to be due to the component of the interplanetary magnetic field near the ecliptic perpendicular to the earth-sun direction. It is suggested that the observed effect on the ground originates in the front of the magnetosphere
Socio-economic inequalities in fragility fracture outcomes:a systematic review and meta-analysis of prognostic observational studies
Identification of amyloidogenic proteins in the microbiomes of a rat Parkinson's disease model and wild-type rats
Cross seeding between amyloidogenic proteins in the gut is receiving increasing attention as a possible mechanism for initiation or acceleration of amyloid formation by aggregationâprone proteins such as αSN, which is central in the development of Parkinson's disease (PD). This is particularly pertinent in view of the growing number of functional (i.e., benign and useful) amyloid proteins discovered in bacteria. Here we identify two amyloidogenic proteins, Pr12 and Pr17, in fecal matter from PD transgenic rats and their wild type counterparts, based on their stability against dissolution by formic acid (FA). Both proteins show robust aggregation into ThTâpositive aggregates that contain higherâorder ÎČâsheets and have a fibrillar morphology, indicative of amyloid proteins. In addition, Pr17 aggregates formed in vitro showed significant resistance against FA, suggesting an ability to form highly stable amyloid. Treatment with proteinase K revealed a protected core of approx. 9âkDa. Neither Pr12 nor Pr17, however, affected αSN aggregation in vitro. Thus, amyloidogenicity does not per se lead to an ability to crossâseed fibrillation of αSN. Our results support the use of proteomics and FA to identify amyloidogenic protein in complex mixtures and suggests that there may be numerous functional amyloid proteins in microbiomes
EISCAT observations of unusual flows in the morning sector associated with weak substorm activity
Associations of fat mass and fat-free mass accretion in infancy with body composition and cardiometabolic risk markers at 5 years:The Ethiopian iABC birth cohort study
BackgroundAccelerated growth in early childhood is an established risk factor for later obesity and cardiometabolic disease, but the relative importance of fat mass (FM) and fat-free mass (FFM) accretion is not well understood. We aimed to study how FM and FFM at birth and their accretion during infancy were associated with body composition and cardiometabolic risk markers at 5 years.Methods and findingsHealthy children born at term were enrolled in the Infant Anthropometry and Body Composition (iABC) birth cohort between December 2008 and October 2012 at Jimma University Specialized Hospital in the city of Jimma, Ethiopia. FM and FFM were assessed using air displacement plethysmography a median of 6 times between birth and 6 months of age. In 507 children, we estimated individual FM and FFM at birth and their accretion over 0-3 and 3-6 months of age using linear-spline mixed-effects modelling. We analysed associations of FM and FFM at birth and their accretion in infancy with height, waist circumference, FM, FFM, and cardiometabolic risk markers at 5 years using multiple linear regression analysis. A total of 340 children were studied at the 5-year follow-up (mean age: 60.0 months; girls: 50.3%; mean wealth index: 45.5 out of 100; breastfeeding status at 4.5 to 6 months post-partum: 12.5% exclusive, 21.4% almost exclusive, 60.6% predominant, 5.5% partial/none). Higher FM accretion in infancy was associated with higher FM and waist circumference at 5 years. For instance, 100-g/month higher FM accretion in the periods 0-3 and 3-6 months was associated with 339 g (95% CI: 243-435 g, p ConclusionsFM accretion in early life was positively associated with markers of adiposity and lipid metabolism, but not with blood pressure and cardiometabolic markers related to glucose homeostasis. FFM accretion was primarily related to linear growth and FFM at 5 years
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