Nimbus 7 Solar Backscatter Ultraviolet (SBUV) spectral scan solar irradiance and Earth radiance product user's guide

The archived tape products from the spectral scan mode measurements of solar irradiance (SUNC tapes) and Earth radiance (EARTH tapes) by the Solar Backscatter UV (SBUV) instrument aboard Nimbus 7 are described. Incoming radiation from 160 to 400 nm is measured at intervals of 0.2 nm. The scan-to-scan repeatability of the solar irradiance measurements ranges from approximately 0.5 to 1 percent longward of 280 nm, to 2 percent around 210 nm and 4 percent near 175 nm. The repeatability of the Earth radiance values ranges from 2 to 3 percent at longer wavelengths and low zenith angles to 10 percent at shorter wavelengths and high zenith angles. The tape formats are described in detail, including file structure and contents of each type of record. Catalogs of the tapes and the time period covered are provided, along with lists of the days lacking solar irradiance measurements and the days dedicated to Earth radiance measurements. The method for production of the tapes is outlined and quality control measures are described. How radiances and irradiances are derived from the raw counts, the corrections for changes in instrument sensitivity, and related uncertainties are discussed

Effect of fibre loading on the microstructural, electrical, and mechanical properties of carbon fibre incorporated smart cement-based composites

Carbon fibre incorporated smart cement-based composite has great potential for the multifunctional health monitoring of concrete structures. This paper presents the microstructural, electrical, and mechanical properties of smart cement-based composites incorporating chopped carbon fibres from low dosages at 0–0.1% by volume (vol%) with detailed intervals, to high dosages up to 2.4 vol%. In comparison to a plain mortar, smart cement-based composites at all fibre contents had higher flexural strength. A 95% improvement in flexural strength was obtained at a fibre content of 0.3 vol%, whereas compressive strength increased up to a fibre content of 1.0 vol%, with the highest improvement, 105%, at 0.2 vol%. The bulk conductivity of smart cement-based composites underwent a double percolation process where the percolation zone of the fibres was identified at fibre contents of 0–0.1 vol% and the percolation zone of the capillary pores resided at fibre contents of 2.1–2.4 vol% indicating an extremely low durability. This study presents the laboratory characterization on smart cement-based composites where the fundamentals of the transitional behaviours of the mechanical properties and the percolation in electrical property through fibre loading were studied, which is a necessary step prior to the assessment of the self-sensing performance. The impact of this study will enable the physical properties of carbon fibre incorporated smart cement-based composites to be optimized through the design and manufacturing process. This will lead to robust performance and superior in-situ multi-functional health monitoring of concrete structures.</p

Episodic Stream Acidification Caused by Atmospheric Deposition of Sea Salts at Acadia National Park, Maine, United States

Major episodic acidifications were observed on several occasions in first-order brooks at Acadia National Park, Mount Desert Island, Maine. Short-term declines of up to 2 pH units and 130-mu-eq L-1 acid-neutralizing capacity were caused by HCl from soil solutions, rather than by H2SO4 or HNO3 from precipitation, because (1) SO4 concentrations were constant or decreased during the pH depression, (2) Cl concentrations were greatest at the time of lowest pH, and (3) Na:Cl ratios decreased from values much greater than those in precipitation (a result of chemical weathering), to values equal to or less than those in precipitation. Dilution, increases in NO3 concentrations, or increased export or organic acidity from soils were insufficient to cause the observed decreases in pH. These data represent surface water acidifications due primarily to an ion exchange salt effect of Na+ for H+ in soil solution, and secondarily to dilution, neither of which is a consequence of acidic deposition. The requisite conditions for a major episodic salt effect acidification include acidic soils, and either an especially salt-laden wet precipitation event, or a period of accumulation of marine salts from dry deposition, followed by wet inputs

Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector

The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially-separate pixels we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a faster timing response than the one-pixel regime.Comment: 11 pages, 2 figure

Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones

A phase field method for tomographic reconstruction from limited data

Classical tomographic reconstruction methods fail for problems in which there is extreme temporal and spatial sparsity in the measured data. Reconstruction of coronal mass ejections (CMEs), a space weather phenomenon with potential negative effects on the Earth, is one such problem. However, the topological complexity of CMEs renders recent limited data reconstruction methods inapplicable. We propose an energy function, based on a phase field level set framework, for the joint segmentation and tomographic reconstruction of CMEs from measurements acquired by coronagraphs, a type of solar telescope. Our phase field model deals easily with complex topologies, and is more robust than classical methods when the data are very sparse. We use a fast variational algorithm that combines the finite element method with a trust region variant of Newton’s method to minimize the energy. We compare the results obtained with our model to classical regularized tomography for synthetic CME-like images

Modular Nucleic Acid Assembled p/MHC Microarrays for Multiplexed Sorting of Antigen-Specific T Cells

The human immune system consists of a large number of T cells capable of recognizing and responding to antigens derived from various sources. The development of peptide-major histocompatibility (p/MHC) tetrameric complexes has enabled the direct detection of these antigen-specific T cells. With the goal of increasing throughput and multiplexing of T cell detection, protein microarrays spotted with defined p/MHC complexes have been reported, but studies have been limited due to the inherent instability and reproducibility of arrays produced via conventional spotted methods. Herein, we report on a platform for the detection of antigen-specific T cells on glass substrates that offers significant advantages over existing surface-bound schemes. In this approach, called “Nucleic Acid Cell Sorting (NACS)”, single-stranded DNA oligomers conjugated site-specifically to p/MHC tetramers are employed to immobilize p/MHC tetramers via hybridization to a complementary-printed substrate. Fully assembled p/MHC arrays are used to detect and enumerate T cells captured from cellular suspensions, including primary human T cells collected from cancer patients. NACS arrays outperform conventional spotted arrays assessed in key criteria such as repeatability and homogeneity. The versatility of employing DNA sequences for cell sorting is exploited to enable the programmed, selective release of target populations of immobilized T cells with restriction endonucleases for downstream analysis. Because of the performance, facile and modular assembly of p/MHC tetramer arrays, NACS holds promise as a versatile platform for multiplexed T cell detection

Watching individual molecules flex within lipid membranes using SERS.

Interrogating individual molecules within bio-membranes is key to deepening our understanding of biological processes essential for life. Using Raman spectroscopy to map molecular vibrations is ideal to non-destructively 'fingerprint' biomolecules for dynamic information on their molecular structure, composition and conformation. Such tag-free tracking of molecules within lipid bio-membranes can directly connect structure and function. In this paper, stable co-assembly with gold nano-components in a 'nanoparticle-on-mirror' geometry strongly enhances the local optical field and reduces the volume probed to a few nm(3), enabling repeated measurements for many tens of minutes on the same molecules. The intense gap plasmons are assembled around model bio-membranes providing molecular identification of the diffusing lipids. Our experiments clearly evidence measurement of individual lipids flexing through telltale rapid correlated vibrational shifts and intensity fluctuations in the Raman spectrum. These track molecules that undergo bending and conformational changes within the probe volume, through their interactions with the environment. This technique allows for in situ high-speed single-molecule investigations of the molecules embedded within lipid bio-membranes. It thus offers a new way to investigate the hidden dynamics of cell membranes important to a myriad of life processes.We acknowledge financial support from EPSRC grant EP/G060649/1, EP/I012060/1, ERC grant LINASS 320503. FB acknowledges support from the Winton Programme for the Physics of Sustainability.This is the final published version. It's also available from Nature Publishing at http://www.nature.com/srep/2014/140812/srep05940/full/srep05940.html

Red Cells Genetically Deficient in Carbonic Anhydrase II Have Elevated Levels of a Carbonic Anhydrase Indistinguishable from Muscle CA III a

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71425/1/j.1749-6632.1984.tb12351.x.pd