Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates

International audienceA light aircraft was equipped with a bank of Condensation Particle Counters (CPCs) (50% cut from 3?5.4?9.6 nm) and a nano-Scanning Mobility Particle Sizer (nSMPS) and deployed along the west coast of Ireland, in the vicinity of Mace Head. The objective of the exercise was to provide high resolution micro-physical measurements of the coastal nucleation mode in order to map the spatial extent of new particle production regions and to evaluate the evolution, and associated growth rates of the coastal nucleation-mode aerosol plume. Results indicate that coastal new particle production is occurring over most areas along the land-sea interface with peak concentrations at the coastal plume-head in excess of 106 cm?3. Pseudo-Lagrangian studies of the coastal plume evolution illustrated significant growth of new particles to sizes in excess of 8 nm approximately 10 km downwind of the source region. Close to the plume head (?1, decreasing gradually to 53?72 nm h?1 at 3 km. Further along the plume, at distances up to 10 km, the growth rates are calculated to be 17?32 nm h?1. Growth rates of this magnitude suggest that after a couple of hours, coastal nucleation mode particles can reach significant sizes where they can contribution to the regional aerosol loading

Advances in Nonlinear Matched Filtering

Symmetric nonlinear matched filters (SNMF’s) involve the transformation of the signal spectrum and the filter transfer function through pointwise nonlinearities before they are multiplied in the transform domain. The resulting system is analogous to a 3-layer neural net The experimental and theoretical results discussed indicate that SNMF’s hold considerable potential to achieve high-power of discrimination, resolution and large SNR. The statistical analysis of a particular SNMF in the 2-class problem indicates that the performance coefficient of the SNMF is about four times larger than the performance coefficient of the classical matched filter. In terms of resolving closeby signals, there seems to be no limit to die achievable resolution. However, intermodulation noise has to be carefully monitored

Methanol Extract of Hydroclathrus clathratus Inhibits Production of Nitric Oxide, Prostaglandin E2 and Tumor Necrosis Factor-&#945 in Lipopolysaccharidestimulated BV2 Microglial Cells via Inhibition of NF-&#954B Activity

Purpose: Hydroclathrus clathratus is a brown marine seaweed known to possess anti-cancer, anti-herpetic, and anti-coagulant activities. The present study is aimed at investigating some anti-inflammatory effects of H. clathratus.Methods: We investigated the anti-inflammatory effects of the methanol extract of H. clathratus (MEHC) by expression of mRNA and protein using RT-PCR and Western blot analysis in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. The level of nitric oxide (NO) production was analyzed using Griess reaction. The release of prostaglandin E2 (PGE2) and tumor necrosis factor-α (TNF-α) were determined using sandwich ELISA. NF-κB activation was detected using EMSA methods.Results: The results obtained indicate that the extract (MEHC) inhibited LPS-induced NO, PGE2, and TNF-α production without any significant cytotoxicity (p < 0.05). MEHC also inhibited production of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and TNF-α mRNA in LPS-stimulated BV2 microglial cells. In addition, MEHC significantly reduced (p < 0.05) nuclear translocation of the nuclear factor-κB (NF-κB) subunits, p50 and p65, and its DNA-binding activity in LPS-stimulated BV2 microglial cells.Conclusion: These results suggest that MEHC suppresses the induction of TNF-α, as well as iNOS and COX-2 expression, by blocking LPS-induced NF-κB activation.Keywords: Hydroclathrus clathratus, Nitric oxide, Prostaglandin E2, Tumor necrosis factor-α, Nuclear factor-κ

Test of the Jarzynski and Crooks Fluctuation Relations in an Electronic System

Recent progress on micro- and nanometer-scale manipulation has opened the possibility to probe systems small enough that thermal fluctuations of energy and coordinate variables can be significant compared with their mean behavior. We present an experimental study of nonequilibrium thermodynamics in a classical two-state system, namely, a metallic single-electron box. We have measured with high statistical accuracy the distribution of dissipated energy as single electrons are transferred between the box electrodes. The obtained distributions obey Jarzynski and Crooks fluctuation relations. A comprehensive microscopic theory exists for the system, enabling the experimental distributions to be reproduced without fitting parameters.Peer reviewe

GPS-Based Precision Baseline Reconstruction for the TanDEM-X SAR-Formation

The TanDEM-X formation employs two separate spacecraft to collect interferometric Synthetic Aperture Radar (SAR) measurements over baselines of about 1 km. These will allow the generation ofa global Digital Elevation Model (DEM) with an relative vertical accuracy of 2-4 m and a 10 m ground resolution. As part of the ground processing, the separation of the SAR antennas at the time of each data take must be reconstructed with a 1 mm accuracy using measurements from two geodetic grade GPS receivers. The paper discusses the TanDEM-X mission as well as the methods employed for determining the interferometric baseline with utmost precision. Measurements collected during the close fly-by of the two GRACE satellites serve as a reference case to illustrate the processing concept, expected accuracy and quality control strategies

Exploiting Inter- and Intra-Memory Asymmetries for Data Mapping in Hybrid Tiered-Memories

Modern computing systems are embracing hybrid memory comprising of DRAM and non-volatile memory (NVM) to combine the best properties of both memory technologies, achieving low latency, high reliability, and high density. A prominent characteristic of DRAM-NVM hybrid memory is that it has NVM access latency much higher than DRAM access latency. We call this inter-memory asymmetry. We observe that parasitic components on a long bitline are a major source of high latency in both DRAM and NVM, and a significant factor contributing to high-voltage operations in NVM, which impact their reliability. We propose an architectural change, where each long bitline in DRAM and NVM is split into two segments by an isolation transistor. One segment can be accessed with lower latency and operating voltage than the other. By introducing tiers, we enable non-uniform accesses within each memory type (which we call intra-memory asymmetry), leading to performance and reliability trade-offs in DRAM-NVM hybrid memory. We extend existing NVM-DRAM OS in three ways. First, we exploit both inter- and intra-memory asymmetries to allocate and migrate memory pages between the tiers in DRAM and NVM. Second, we improve the OS's page allocation decisions by predicting the access intensity of a newly-referenced memory page in a program and placing it to a matching tier during its initial allocation. This minimizes page migrations during program execution, lowering the performance overhead. Third, we propose a solution to migrate pages between the tiers of the same memory without transferring data over the memory channel, minimizing channel occupancy and improving performance. Our overall approach, which we call MNEME, to enable and exploit asymmetries in DRAM-NVM hybrid tiered memory improves both performance and reliability for both single-core and multi-programmed workloads.Comment: 15 pages, 29 figures, accepted at ACM SIGPLAN International Symposium on Memory Managemen