405 research outputs found
Statistical Isotropy of CMB Polarization Maps
We formulate statistical isotropy of CMB anisotropy maps in its most general
form. We also present a fast and orientation independent statistical method to
determine deviations from statistical isotropy in CMB polarization maps.
Importance of having statistical tests of departures from SI for CMB
polarization maps lies not only in interesting theoretical motivations but also
in testing cleaned CMB polarization maps for observational artifacts such as
residuals from polarized foreground emission. We propose a generalization of
the Bipolar Power Spectrum (BiPS) to polarization maps. Application to the
observed CMB polarization maps will be soon possible after the release of WMAP
three year data. As a demonstration we show that for E-polarization this test
can detect breakdown of statistical isotropy due to polarized synchrotron
foreground.Comment: 6 pages, 2 figures, Conclusions & results unchanged; Extension to
cutsky included (discussion & references added); Matches version accepted to
Phys. Rev. D Rapid Com
Nanoparticles of Cerium Oxide Targeted to an Amyloid-Beta Antigen of Alzheimer\u27s Disease and Associated Methods
Disclosed is a composition immunologically targeted to Alzheimer’s disease (AD), the composition containing amine functionalized nanoparticles of Cerium oxide coated with polyethylene glycol and bearing an antibody specific for an amyloid-beta antigen associated with AD. The invention also includes a medication manufactured with the targeted nanoceria particles and methods of treatment by administering the targeted nanoceria particles to patients in need thereof
Investigation of voltage regulation in grid–connected PV system
In the present scenario the power demand on the load side is increasing day by day, so to balance the power demand and power supply various renewable energy comes to picture as the additional source of electricity generation. The power generated by various renewable resources such as solar, wind, tidal energy and geothermal sources is environmentally clean and have a less emission impact. Out of which PV system draws more attention because it generates energy with a much lower level of carbon dioxide emissions. In the proposed work the objective is to investigate the synchronisation of the grid-connected PV system in terms of voltage and frequency. It includes the P-V characteristics under the circumstances of MPPT technique such as perturb & observe (P&O) method can able to track the local maximum point. The proposed inverter is a voltage source H-Bridge inverter which is controlled using a Clarke and Park transformation to drive a controlled current into the grid to maintain the THD value within the standards. As the grid frequency is fluctuating between SRF-PLL is generally used to fix the output frequency and phase of the grid. It also includes with the design of a three-phase H-bridge inverter as an interface between PV system and grid system. The proposed work is designed and simulated in MATLAB SIMULINK 2017b environment
IκBɛ provides negative feedback to control NF-κB oscillations, signaling dynamics, and inflammatory gene expression
NF-κB signaling is known to be critically regulated by the NF-κB–inducible inhibitor protein IκBα. The resulting negative feedback has been shown to produce a propensity for oscillations in NF-κB activity. We report integrated experimental and computational studies that demonstrate that another IκB isoform, IκBɛ, also provides negative feedback on NF-κB activity, but with distinct functional consequences. Upon stimulation, NF-κB–induced transcription of IκBɛ is delayed, relative to that of IκBα, rendering the two negative feedback loops to be in antiphase. As a result, IκBɛ has a role in dampening IκBα-mediated oscillations during long-lasting NF-κB activity. Furthermore, we demonstrate the requirement of both of these distinct negative feedback regulators for the termination of NF-κB activity and NF-κB–mediated gene expression in response to transient stimulation. Our findings extend the capabilities of a computational model of IκB–NF-κB signaling and reveal a novel regulatory module of two antiphase negative feedback loops that allows for the fine-tuning of the dynamics of a mammalian signaling pathway
Giant coherence in driven systems
We study the noise-induced currents and reliability or coherence of transport
in two different classes of rocking ratchets. For this, we consider the motion
of Brownian particles in the over damped limit in both adiabatic and
non-adiabatic regimes subjected to unbiased temporally symmetric and asymmetric
periodic driving force. In the case of a time symmetric driving, we find that
even in the presence of a spatially symmetric simple sinusoidal potential,
highly coherent transport occurs. These ratchet systems exhibit giant coherence
of transport in the regime of parameter space where unidirectional currents in
the deterministic case are observed. Outside this parameter range, i.e., when
current vanishes in the deterministic regime, coherence in transport is very
low. The transport coherence decreases as a function of temperature and is a
non-monotonic function of the amplitude of driving. The transport becomes
unreliable as we go from the adiabatic to the non-adiabatic domain of
operation.Comment: 15 pages, 9 figures, replaced by the version to appear in JSTA
Fast readout of the COMPASS RICH CsI-MWPC photon chambers
Abstract A new readout system for CsI-coated MWPCs, used in the COMPASS RICH detector, has been proposed and tested in nominal high-rate conditions. It is based on the APV25-S1 analog sampling chip, and will replace the Gassiplex chip readout used up to now. The APV chip, originally designed for silicon microstrip detectors, is shown to perform well even with "slow" signals from a MWPC, keeping a signal-to-noise ratio of 9. For every trigger the system reads three consecutive in-time samples, thus allowing to extract information on the signal shape and its timing. The effective time window is reduced from ∼3 μs for the Gassiplex to below 400 ns for the APV25-S1 chip, reducing pile-up events at high particle rate. A significant improvement of the signal-to-background ratio by a factor 5–6 with respect to the original readout has been measured in the central region of the RICH detector. Due to its pipelined architecture, the new readout system also considerably reduces the dead time per event, allowing efficient data taking at higher trigger rate
Long Spin Coherence and Relaxation Times in Nanodiamonds Milled from Polycrystalline C Diamond
The negatively charged nitrogen-vacancy centre (NV) in diamond has been
utilized in a wide variety of sensing applications. The centre's long spin
coherence and relaxation times (, and ) at room temperature
are crucial to this, as they often limit sensitivity. Using NV centres in
nanodiamonds allows for operations in environments inaccessible to bulk
diamond, such as intracellular sensing. We report long spin coherence and
relaxation times at room temperature for single NV centres in
isotopically-purified polycrystalline ball-milled nanodiamonds. Using a
spin-locking pulse sequence, we observe spin coherence times, , up 786
200 s. We also measure times up to 2.06 0.24 s
and times up to 4.32 0.60 ms. Scanning electron microscopy and
atomic force microscopy measurements show that the diamond containing the
NV centre with the longest time is smaller than 100 nm. EPR
measurements give an N concentration of 0.15 0.02 ppm for the
nanodiamond sample.Comment: 13 pages, 3 figure
Light induced decoupling of electronic and magnetic properties in manganites
The strongly correlated material La0.7Sr0.3MnO3 (LSMO) exhibits
metal-to-insulator and magnetic transition near room temperature. Although the
physical properties of LSMO can be manipulated by strain, chemical doping,
temperature, or magnetic field, they often require large external stimuli. To
include additional flexibility and tunability, we developed a hybrid
optoelectronic heterostructure that uses photocarrier injection from cadmium
sulfide (CdS) to an LSMO layer to change its electrical conductivity. LSMO
exhibits no significant optical response, however, the CdS/LSMO
heterostructures show an enhanced conductivity, with ~ 37 % resistance drop, at
the transition temperature under light stimuli. This enhanced conductivity in
response to light is comparable to the effect of a 9 T magnetic field in pure
LSMO. Surprisingly, the optical and magnetic responses of CdS/LSMO
heterostructures are decoupled and exhibit different effects when both stimuli
are applied. This unexpected behavior shows that heterostructuring strongly
correlated oxides may require a new understanding of the coupling of physical
properties across the transitions and provide the means to implement new
functionalities
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