Sensor-scheduling simulation of disparate sensors for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Hobson, T.; Clarkson, I.

2011-09-01

The art and science of space situational awareness (SSA) has been practised and developed from the time of Sputnik. However, recent developments, such as the accelerating pace of satellite launch, the proliferation of launch capable agencies, both commercial and sovereign, and recent well-publicised collisions involving man-made space objects, has further magnified the importance of timely and accurate SSA. The United States Strategic Command (USSTRATCOM) operates the Space Surveillance Network (SSN), a global network of sensors tasked with maintaining SSA. The rapidly increasing number of resident space objects will require commensurate improvements in the SSN. Sensors are scarce resources that must be scheduled judiciously to obtain measurements of maximum utility. Improvements in sensor scheduling and fusion, can serve to reduce the number of additional sensors that may be required. Recently, Hill et al. [1] have proposed and developed a simulation environment named TASMAN (Tasking Autonomous Sensors in a Multiple Application Network) to enable testing of alternative scheduling strategies within a simulated multi-sensor, multi-target environment. TASMAN simulates a high-fidelity, hardware-in-the-loop system by running multiple machines with different roles in parallel. At present, TASMAN is limited to simulations involving electro-optic sensors. Its high fidelity is at once a feature and a limitation, since supercomputing is required to run simulations of appreciable scale. In this paper, we describe an alternative, modular and scalable SSA simulation system that can extend the work of Hill et al with reduced complexity, albeit also with reduced fidelity. The tool has been developed in MATLAB and therefore can be run on a very wide range of computing platforms. It can also make use of MATLAB’s parallel processing capabilities to obtain considerable speed-up. The speed and flexibility so obtained can be used to quickly test scheduling algorithms even with a relatively large number of space objects. We further describe an application of the tool by exploring how the relative mixture of electro-optical and radar sensors can impact the scheduling, fusion and achievable accuracy of an SSA system. By varying the mixture of sensor types, we are able to characterise the main advantages and disadvantages of each configuration.

Python-based geometry preparation and simulation visualization toolkits for STEPS

PubMed Central

Chen, Weiliang; De Schutter, Erik

2014-01-01

STEPS is a stochastic reaction-diffusion simulation engine that implements a spatial extension of Gillespie's Stochastic Simulation Algorithm (SSA) in complex tetrahedral geometries. An extensive Python-based interface is provided to STEPS so that it can interact with the large number of scientific packages in Python. However, a gap existed between the interfaces of these packages and the STEPS user interface, where supporting toolkits could reduce the amount of scripting required for research projects. This paper introduces two new supporting toolkits that support geometry preparation and visualization for STEPS simulations. PMID:24782754

NEOPROP: A NEO Propagator for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Zuccarelli, Valentino; Bancelin, David; Weikert, Sven; Thuillot, William; Hestroffer, Daniel; Yabar Valle, Celia; Koschny, Detlef

2013-09-01

The overall aim of the Space Situational Awareness (SSA) Preparatory Programme is to support the European independent utilisation of and access to space for research or services, through providing timely and quality data, information, services and knowledge regarding the environment, the threats and the sustainable exploitation of the outer space surrounding our planet Earth. The SSA system will comprise three main segments:• Space Weather (SWE) monitoring and forecast• Near-Earth Objects (NEO) survey and follow-up• Space Surveillance and Tracking (SST) of man-made space objectsCurrently, there are over 600.000 asteroids known in our Solar System, where more than 9.500 of these are NEOs. These could potentially hit our planet and depending on their size could produce considerable damage. For this reason NEOs deserve active detection and tracking efforts.The role of the SSA programme is to provide warning services against potential asteroid impact hazards, including discovery, identification, orbit prediction and civil alert capabilities. ESA is now working to develop a NEO Coordination Centre which will later evolve into a SSA-NEO Small Bodies Data Centre (SBDC), located at ESA/ESRIN, Italy. The Software prototype developed in the frame of this activity may be later implemented as a part of the SSA-NEO programme simulators aimed at assessing the trajectory of asteroids. There already exist different algorithms to predict orbits for NEOs. The objective of this activity is to come up with a different trajectory prediction algorithm, which allows an independent validation of the current algorithms within the SSA-NEO segment (e.g. NEODyS, JPL Sentry System).The key objective of this activity was to design, develop, test, verify, and validate trajectory prediction algorithm of NEOs in order to be able to computeanalytically and numerically the minimum orbital intersection distances (MOIDs).The NEOPROP software consists of two separate modules/tools:1. The Analytical Module makes use of analytical algorithms in order to rapidly assess the impact risk of a NEO. It is responsible for the preliminary analysis. Orbit Determination algorithms, as the Gauss and the Linear Least Squares (LLS) methods, will determine the initial state (from MPC observations), along with its uncertainty, and the MOID of the NEO (analytically).2. The Numerical Module makes use of numerical algorithms in order to refine and to better assess the impact probabilities. The initial state provided by the orbit determination process will be used to numerically propagate the trajectory. The numerical propagation can be run in two modes: one faster ("fast analysis"), in order to get a fast evaluation of the trajectory and one more precise ("complete analysis") taking into consideration more detailed perturbation models. Moreover, a configurable number of Virtual Asteroids (VAs) will be numerically propagated in order to determine the Earth closest approach. This new "MOID" computation differs from the analytical one since it takes into consideration the full dynamics of the problem.

Indirect estimation of absorption properties for fine aerosol particles using AATSR observations: a case study of wildfires in Russia in 2010

NASA Astrophysics Data System (ADS)

Rodriguez, E.; Kolmonen, P.; Virtanen, T. H.; Sogacheva, L.; Sundstrom, A.-M.; de Leeuw, G.

2015-08-01

The Advanced Along-Track Scanning Radiometer (AATSR) on board the ENVISAT satellite is used to study aerosol properties. The retrieval of aerosol properties from satellite data is based on the optimized fit of simulated and measured reflectances at the top of the atmosphere (TOA). The simulations are made using a radiative transfer model with a variety of representative aerosol properties. The retrieval process utilizes a combination of four aerosol components, each of which is defined by their (lognormal) size distribution and a complex refractive index: a weakly and a strongly absorbing fine-mode component, coarse mode sea salt aerosol and coarse mode desert dust aerosol). These components are externally mixed to provide the aerosol model which in turn is used to calculate the aerosol optical depth (AOD). In the AATSR aerosol retrieval algorithm, the mixing of these components is decided by minimizing the error function given by the sum of the differences between measured and calculated path radiances at 3-4 wavelengths, where the path radiances are varied by varying the aerosol component mixing ratios. The continuous variation of the fine-mode components allows for the continuous variation of the fine-mode aerosol absorption. Assuming that the correct aerosol model (i.e. the correct mixing fractions of the four components) is selected during the retrieval process, also other aerosol properties could be computed such as the single scattering albedo (SSA). Implications of this assumption regarding the ratio of the weakly/strongly absorbing fine-mode fraction are investigated in this paper by evaluating the validity of the SSA thus obtained. The SSA is indirectly estimated for aerosol plumes with moderate-to-high AOD resulting from wildfires in Russia in the summer of 2010. Together with the AOD, the SSA provides the aerosol absorbing optical depth (AAOD). The results are compared with AERONET data, i.e. AOD level 2.0 and SSA and AAOD inversion products. The RMSE (root mean square error) is 0.03 for SSA and 0.02 for AAOD lower than 0.05. The SSA is further evaluated by comparison with the SSA retrieved from the Ozone Monitoring Instrument (OMI). The SSA retrieved from both instruments show similar features, with generally lower AATSR-estimated SSA values over areas affected by wildfires.

Backward-stochastic-differential-equation approach to modeling of gene expression

NASA Astrophysics Data System (ADS)

Shamarova, Evelina; Chertovskih, Roman; Ramos, Alexandre F.; Aguiar, Paulo

2017-03-01

In this article, we introduce a backward method to model stochastic gene expression and protein-level dynamics. The protein amount is regarded as a diffusion process and is described by a backward stochastic differential equation (BSDE). Unlike many other SDE techniques proposed in the literature, the BSDE method is backward in time; that is, instead of initial conditions it requires the specification of end-point ("final") conditions, in addition to the model parametrization. To validate our approach we employ Gillespie's stochastic simulation algorithm (SSA) to generate (forward) benchmark data, according to predefined gene network models. Numerical simulations show that the BSDE method is able to correctly infer the protein-level distributions that preceded a known final condition, obtained originally from the forward SSA. This makes the BSDE method a powerful systems biology tool for time-reversed simulations, allowing, for example, the assessment of the biological conditions (e.g., protein concentrations) that preceded an experimentally measured event of interest (e.g., mitosis, apoptosis, etc.).

Backward-stochastic-differential-equation approach to modeling of gene expression.

PubMed

Shamarova, Evelina; Chertovskih, Roman; Ramos, Alexandre F; Aguiar, Paulo

2017-03-01

In this article, we introduce a backward method to model stochastic gene expression and protein-level dynamics. The protein amount is regarded as a diffusion process and is described by a backward stochastic differential equation (BSDE). Unlike many other SDE techniques proposed in the literature, the BSDE method is backward in time; that is, instead of initial conditions it requires the specification of end-point ("final") conditions, in addition to the model parametrization. To validate our approach we employ Gillespie's stochastic simulation algorithm (SSA) to generate (forward) benchmark data, according to predefined gene network models. Numerical simulations show that the BSDE method is able to correctly infer the protein-level distributions that preceded a known final condition, obtained originally from the forward SSA. This makes the BSDE method a powerful systems biology tool for time-reversed simulations, allowing, for example, the assessment of the biological conditions (e.g., protein concentrations) that preceded an experimentally measured event of interest (e.g., mitosis, apoptosis, etc.).

Empirical retrieval of sea spray aerosol production using satellite microwave radiometry

NASA Astrophysics Data System (ADS)

Savelyev, I. B.; Yelland, M. J.; Norris, S. J.; Salisbury, D.; Pascal, R. W.; Bettenhausen, M. H.; Prytherch, J.; Anguelova, M. D.; Brooks, I. M.

2017-12-01

This study presents a novel approach to obtaining global sea spray aerosol (SSA) production source term by relying on direct satellite observations of the ocean surface, instead of more traditional approaches driven by surface meteorology. The primary challenge in developing this empirical algorithm is to compile a calibrated, consistent dataset of SSA surface flux collected offshore over a variety of conditions (i.e., regions and seasons), thus representative of the global SSA production variability. Such dataset includes observations from SEASAW, HiWASE, and WAGES field campaigns, during which the SSA flux was measured from the bow of a research vessel using consistent and state-of-the-art eddy covariance methodology. These in situ data are matched to observations of the state of the ocean surface from Windsat polarimetric microwave satellite radiometer. Previous studies demonstrated the ability of WindSat to detect variations in surface waves slopes, roughness and foam, which led to the development of retrieval algorithms for surface wind vector and more recently whitecap fraction. Similarly, in this study, microwave emissions from the ocean surface are matched to and calibrated against in situ observations of the SSA production flux. The resulting calibrated empirical algorithm is applicable for retrieval of SSA source term throughout the duration of Windsat mission, from 2003 to present.

Delay chemical master equation: direct and closed-form solutions

PubMed Central

Leier, Andre; Marquez-Lago, Tatiana T.

2015-01-01

The stochastic simulation algorithm (SSA) describes the time evolution of a discrete nonlinear Markov process. This stochastic process has a probability density function that is the solution of a differential equation, commonly known as the chemical master equation (CME) or forward-Kolmogorov equation. In the same way that the CME gives rise to the SSA, and trajectories of the latter are exact with respect to the former, trajectories obtained from a delay SSA are exact representations of the underlying delay CME (DCME). However, in contrast to the CME, no closed-form solutions have so far been derived for any kind of DCME. In this paper, we describe for the first time direct and closed solutions of the DCME for simple reaction schemes, such as a single-delayed unimolecular reaction as well as chemical reactions for transcription and translation with delayed mRNA maturation. We also discuss the conditions that have to be met such that such solutions can be derived. PMID:26345616

Delay chemical master equation: direct and closed-form solutions.

PubMed

Leier, Andre; Marquez-Lago, Tatiana T

2015-07-08

The stochastic simulation algorithm (SSA) describes the time evolution of a discrete nonlinear Markov process. This stochastic process has a probability density function that is the solution of a differential equation, commonly known as the chemical master equation (CME) or forward-Kolmogorov equation. In the same way that the CME gives rise to the SSA, and trajectories of the latter are exact with respect to the former, trajectories obtained from a delay SSA are exact representations of the underlying delay CME (DCME). However, in contrast to the CME, no closed-form solutions have so far been derived for any kind of DCME. In this paper, we describe for the first time direct and closed solutions of the DCME for simple reaction schemes, such as a single-delayed unimolecular reaction as well as chemical reactions for transcription and translation with delayed mRNA maturation. We also discuss the conditions that have to be met such that such solutions can be derived.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Fuke, E-mail: wufuke@mail.hust.edu.cn; Tian, Tianhai, E-mail: tianhai.tian@sci.monash.edu.au; Rawlings, James B., E-mail: james.rawlings@wisc.edu

The frequently used reduction technique is based on the chemical master equation for stochastic chemical kinetics with two-time scales, which yields the modified stochastic simulation algorithm (SSA). For the chemical reaction processes involving a large number of molecular species and reactions, the collection of slow reactions may still include a large number of molecular species and reactions. Consequently, the SSA is still computationally expensive. Because the chemical Langevin equations (CLEs) can effectively work for a large number of molecular species and reactions, this paper develops a reduction method based on the CLE by the stochastic averaging principle developed in themore » work of Khasminskii and Yin [SIAM J. Appl. Math. 56, 1766–1793 (1996); ibid. 56, 1794–1819 (1996)] to average out the fast-reacting variables. This reduction method leads to a limit averaging system, which is an approximation of the slow reactions. Because in the stochastic chemical kinetics, the CLE is seen as the approximation of the SSA, the limit averaging system can be treated as the approximation of the slow reactions. As an application, we examine the reduction of computation complexity for the gene regulatory networks with two-time scales driven by intrinsic noise. For linear and nonlinear protein production functions, the simulations show that the sample average (expectation) of the limit averaging system is close to that of the slow-reaction process based on the SSA. It demonstrates that the limit averaging system is an efficient approximation of the slow-reaction process in the sense of the weak convergence.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duncan, Andrew, E-mail: a.duncan@imperial.ac.uk; Erban, Radek, E-mail: erban@maths.ox.ac.uk; Zygalakis, Konstantinos, E-mail: k.zygalakis@ed.ac.uk

Stochasticity plays a fundamental role in various biochemical processes, such as cell regulatory networks and enzyme cascades. Isothermal, well-mixed systems can be modelled as Markov processes, typically simulated using the Gillespie Stochastic Simulation Algorithm (SSA) [25]. While easy to implement and exact, the computational cost of using the Gillespie SSA to simulate such systems can become prohibitive as the frequency of reaction events increases. This has motivated numerous coarse-grained schemes, where the “fast” reactions are approximated either using Langevin dynamics or deterministically. While such approaches provide a good approximation when all reactants are abundant, the approximation breaks down when onemore » or more species exist only in small concentrations and the fluctuations arising from the discrete nature of the reactions become significant. This is particularly problematic when using such methods to compute statistics of extinction times for chemical species, as well as simulating non-equilibrium systems such as cell-cycle models in which a single species can cycle between abundance and scarcity. In this paper, a hybrid jump-diffusion model for simulating well-mixed stochastic kinetics is derived. It acts as a bridge between the Gillespie SSA and the chemical Langevin equation. For low reactant reactions the underlying behaviour is purely discrete, while purely diffusive when the concentrations of all species are large, with the two different behaviours coexisting in the intermediate region. A bound on the weak error in the classical large volume scaling limit is obtained, and three different numerical discretisations of the jump-diffusion model are described. The benefits of such a formalism are illustrated using computational examples.« less

Simulation And Forecasting of Daily Pm10 Concentrations Using Autoregressive Models In Kagithane Creek Valley, Istanbul

NASA Astrophysics Data System (ADS)

Ağaç, Kübra; Koçak, Kasım; Deniz, Ali

2015-04-01

A time series approach using autoregressive model (AR), moving average model (MA) and seasonal autoregressive integrated moving average model (SARIMA) were used in this study to simulate and forecast daily PM10 concentrations in Kagithane Creek Valley, Istanbul. Hourly PM10 concentrations have been measured in Kagithane Creek Valley between 2010 and 2014 periods. Bosphorus divides the city in two parts as European and Asian parts. The historical part of the city takes place in Golden Horn. Our study area Kagithane Creek Valley is connected with this historical part. The study area is highly polluted because of its topographical structure and industrial activities. Also population density is extremely high in this site. The dispersion conditions are highly poor in this creek valley so it is necessary to calculate PM10 levels for air quality and human health. For given period there were some missing PM10 concentration values so to make an accurate calculations and to obtain exact results gap filling method was applied by Singular Spectrum Analysis (SSA). SSA is a new and efficient method for gap filling and it is an state-of-art modeling. SSA-MTM Toolkit was used for our study. SSA is considered as a noise reduction algorithm because it decomposes an original time series to trend (if exists), oscillatory and noise components by way of a singular value decomposition. The basic SSA algorithm has stages of decomposition and reconstruction. For given period daily and monthly PM10 concentrations were calculated and episodic periods are determined. Long term and short term PM10 concentrations were analyzed according to European Union (EU) standards. For simulation and forecasting of high level PM10 concentrations, meteorological data (wind speed, pressure and temperature) were used to see the relationship between daily PM10 concentrations. Fast Fourier Transformation (FFT) was also applied to the data to see the periodicity and according to these periods models were built in MATLAB an Eviews programmes. Because of the seasonality of PM10 data SARIMA model was also used. The order of autoregression model was determined according to AIC and BIC criteria. The model performances were evaluated from Fractional Bias, Normalized Mean Square Error (NMSE) and Mean Absolute Percentage Error (MAPE). As expected, the results were encouraging. Keywords: PM10, Autoregression, Forecast Acknowledgement The authors would like to acknowledge the financial support by the Scientific and Technological Research Council of Turkey (TUBITAK, project no:112Y319).

Aerosol single-scattering albedo over the global oceans: Comparing PARASOL retrievals with AERONET, OMI, and AeroCom models estimates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacagnina, Carlo; Hasekamp, Otto P.; Bian, Huisheng

2015-09-27

The aerosol Single Scattering Albedo (SSA) over the global oceans is evaluated based on polarimetric measurements by the PARASOL satellite. The retrieved values for SSA and Aerosol Optical Depth (AOD) agree well with the ground-based measurements of the AErosol RObotic NETwork (AERONET). The global coverage provided by the PARASOL observations represents a unique opportunity to evaluate SSA and AOD simulated by atmospheric transport model runs, as performed in the AeroCom framework. The SSA estimate provided by the AeroCom models is generally higher than the SSA retrieved from both PARASOL and AERONET. On the other hand, the mean simulated AOD ismore » about right or slightly underestimated compared with observations. An overestimate of the SSA by the models would suggest that these simulate an overly strong aerosol radiative cooling at top-of-atmosphere (TOA) and underestimate it at surface. This implies that aerosols have a potential stronger impact within the atmosphere than currently simulated.« less

Discrete stochastic simulation methods for chemically reacting systems.

PubMed

Cao, Yang; Samuels, David C

2009-01-01

Discrete stochastic chemical kinetics describe the time evolution of a chemically reacting system by taking into account the fact that, in reality, chemical species are present with integer populations and exhibit some degree of randomness in their dynamical behavior. In recent years, with the development of new techniques to study biochemistry dynamics in a single cell, there are increasing studies using this approach to chemical kinetics in cellular systems, where the small copy number of some reactant species in the cell may lead to deviations from the predictions of the deterministic differential equations of classical chemical kinetics. This chapter reviews the fundamental theory related to stochastic chemical kinetics and several simulation methods based on that theory. We focus on nonstiff biochemical systems and the two most important discrete stochastic simulation methods: Gillespie's stochastic simulation algorithm (SSA) and the tau-leaping method. Different implementation strategies of these two methods are discussed. Then we recommend a relatively simple and efficient strategy that combines the strengths of the two methods: the hybrid SSA/tau-leaping method. The implementation details of the hybrid strategy are given here and a related software package is introduced. Finally, the hybrid method is applied to simple biochemical systems as a demonstration of its application.

The Process of Parallelizing the Conjunction Prediction Algorithm of ESA's SSA Conjunction Prediction Service Using GPGPU

NASA Astrophysics Data System (ADS)

Fehr, M.; Navarro, V.; Martin, L.; Fletcher, E.

2013-08-01

Space Situational Awareness[8] (SSA) is defined as the comprehensive knowledge, understanding and maintained awareness of the population of space objects, the space environment and existing threats and risks. As ESA's SSA Conjunction Prediction Service (CPS) requires the repetitive application of a processing algorithm against a data set of man-made space objects, it is crucial to exploit the highly parallelizable nature of this problem. Currently the CPS system makes use of OpenMP[7] for parallelization purposes using CPU threads, but only a GPU with its hundreds of cores can fully benefit from such high levels of parallelism. This paper presents the adaptation of several core algorithms[5] of the CPS for general-purpose computing on graphics processing units (GPGPU) using NVIDIAs Compute Unified Device Architecture (CUDA).

(abstract) Generic Modeling of a Life Support System for Process Technology Comparisons

NASA Technical Reports Server (NTRS)

Ferrall, J. F.; Seshan, P. K.; Rohatgi, N. K.; Ganapathi, G. B.

1993-01-01

This paper describes a simulation model called the Life Support Systems Analysis Simulation Tool (LiSSA-ST), the spreadsheet program called the Life Support Systems Analysis Trade Tool (LiSSA-TT), and the Generic Modular Flow Schematic (GMFS) modeling technique. Results of using the LiSSA-ST and the LiSSA-TT will be presented for comparing life support systems and process technology options for a Lunar Base and a Mars Exploration Mission.

An application of the Krylov-FSP-SSA method to parameter fitting with maximum likelihood

NASA Astrophysics Data System (ADS)

Dinh, Khanh N.; Sidje, Roger B.

2017-12-01

Monte Carlo methods such as the stochastic simulation algorithm (SSA) have traditionally been employed in gene regulation problems. However, there has been increasing interest to directly obtain the probability distribution of the molecules involved by solving the chemical master equation (CME). This requires addressing the curse of dimensionality that is inherent in most gene regulation problems. The finite state projection (FSP) seeks to address the challenge and there have been variants that further reduce the size of the projection or that accelerate the resulting matrix exponential. The Krylov-FSP-SSA variant has proved numerically efficient by combining, on one hand, the SSA to adaptively drive the FSP, and on the other hand, adaptive Krylov techniques to evaluate the matrix exponential. Here we apply this Krylov-FSP-SSA to a mutual inhibitory gene network synthetically engineered in Saccharomyces cerevisiae, in which bimodality arises. We show numerically that the approach can efficiently approximate the transient probability distribution, and this has important implications for parameter fitting, where the CME has to be solved for many different parameter sets. The fitting scheme amounts to an optimization problem of finding the parameter set so that the transient probability distributions fit the observations with maximum likelihood. We compare five optimization schemes for this difficult problem, thereby providing further insights into this approach of parameter estimation that is often applied to models in systems biology where there is a need to calibrate free parameters. Work supported by NSF grant DMS-1320849.

Generalized binomial τ-leap method for biochemical kinetics incorporating both delay and intrinsic noise

NASA Astrophysics Data System (ADS)

Leier, André; Marquez-Lago, Tatiana T.; Burrage, Kevin

2008-05-01

The delay stochastic simulation algorithm (DSSA) by Barrio et al. [Plos Comput. Biol. 2, 117(E) (2006)] was developed to simulate delayed processes in cell biology in the presence of intrinsic noise, that is, when there are small-to-moderate numbers of certain key molecules present in a chemical reaction system. These delayed processes can faithfully represent complex interactions and mechanisms that imply a number of spatiotemporal processes often not explicitly modeled such as transcription and translation, basic in the modeling of cell signaling pathways. However, for systems with widely varying reaction rate constants or large numbers of molecules, the simulation time steps of both the stochastic simulation algorithm (SSA) and the DSSA can become very small causing considerable computational overheads. In order to overcome the limit of small step sizes, various τ-leap strategies have been suggested for improving computational performance of the SSA. In this paper, we present a binomial τ-DSSA method that extends the τ-leap idea to the delay setting and avoids drawing insufficient numbers of reactions, a common shortcoming of existing binomial τ-leap methods that becomes evident when dealing with complex chemical interactions. The resulting inaccuracies are most evident in the delayed case, even when considering reaction products as potential reactants within the same time step in which they are produced. Moreover, we extend the framework to account for multicellular systems with different degrees of intercellular communication. We apply these ideas to two important genetic regulatory models, namely, the hes1 gene, implicated as a molecular clock, and a Her1/Her 7 model for coupled oscillating cells.

The slow-scale linear noise approximation: an accurate, reduced stochastic description of biochemical networks under timescale separation conditions

PubMed Central

2012-01-01

Background It is well known that the deterministic dynamics of biochemical reaction networks can be more easily studied if timescale separation conditions are invoked (the quasi-steady-state assumption). In this case the deterministic dynamics of a large network of elementary reactions are well described by the dynamics of a smaller network of effective reactions. Each of the latter represents a group of elementary reactions in the large network and has associated with it an effective macroscopic rate law. A popular method to achieve model reduction in the presence of intrinsic noise consists of using the effective macroscopic rate laws to heuristically deduce effective probabilities for the effective reactions which then enables simulation via the stochastic simulation algorithm (SSA). The validity of this heuristic SSA method is a priori doubtful because the reaction probabilities for the SSA have only been rigorously derived from microscopic physics arguments for elementary reactions. Results We here obtain, by rigorous means and in closed-form, a reduced linear Langevin equation description of the stochastic dynamics of monostable biochemical networks in conditions characterized by small intrinsic noise and timescale separation. The slow-scale linear noise approximation (ssLNA), as the new method is called, is used to calculate the intrinsic noise statistics of enzyme and gene networks. The results agree very well with SSA simulations of the non-reduced network of elementary reactions. In contrast the conventional heuristic SSA is shown to overestimate the size of noise for Michaelis-Menten kinetics, considerably under-estimate the size of noise for Hill-type kinetics and in some cases even miss the prediction of noise-induced oscillations. Conclusions A new general method, the ssLNA, is derived and shown to correctly describe the statistics of intrinsic noise about the macroscopic concentrations under timescale separation conditions. The ssLNA provides a simple and accurate means of performing stochastic model reduction and hence it is expected to be of widespread utility in studying the dynamics of large noisy reaction networks, as is common in computational and systems biology. PMID:22583770

Assessing Space and Satellite Environment and System Security

NASA Astrophysics Data System (ADS)

Haith, G.; Upton, S.

Satellites and other spacecraft are key assets and critical vulnerabilities in our communications, surveillance and defense infrastructure. Despite their strategic importance, there are significant gaps in our real-time knowledge of satellite security. One reason is the lack of infrastructure and applications to filter and process the overwhelming amounts of relevant data. Some efforts are addressing this challenge by fusing the data gathered from ground, air and space based sensors to detect and categorize anomalous situations. The aim is to provide decision support for Space Situational Awareness (SSA) and Defensive Counterspace (DCS). Most results have not yielded estimates of impact and cost of a given situation or suggested courses of action (level 3 data fusion). This paper describes an effort to provide high level data fusion for SSA/DCS though two complementary thrusts: threat scenario simulation with Automatic Red Teaming (ART), and historical data warehousing and mining. ART uses stochastic search algorithms (e.g., evolutionary algorithms) to evolve strategies in agent based simulations. ART provides techniques to formally specify anomalous condition scenarios envisioned by subject matter experts and to explore alternative scenarios. The simulation data can then support impact estimates and course of action evaluations. The data mining thrust has focused on finding correlations between subsystems anomalies on MightySat II and publicly available space weather data. This paper describes the ART approach, some potential correlations discovered between satellite subsystem anomalies and space weather events, and future work planned on the project.

Autonomous Integrated Receive System (AIRS) requirements definition. Volume 3: Performance and simulation

NASA Technical Reports Server (NTRS)

Chie, C. M.; Su, Y. T.; Lindsey, W. C.; Koukos, J.

1984-01-01

The autonomous and integrated aspects of the operation of the AIRS (Autonomous Integrated Receive System) are discussed from a system operation point of view. The advantages of AIRS compared to the existing SSA receive chain equipment are highlighted. The three modes of AIRS operation are addressed in detail. The configurations of the AIRS are defined as a function of the operating modes and the user signal characteristics. Each AIRS configuration selection is made up of three components: the hardware, the software algorithms and the parameters used by these algorithms. A comparison between AIRS and the wide dynamics demodulation (WDD) is provided. The organization of the AIRS analytical/simulation software is described. The modeling and analysis is for simulating the performance of the PN subsystem is documented. The frequence acquisition technique using a frequency-locked loop is also documented. Doppler compensation implementation is described. The technological aspects of employing CCD's for PN acquisition are addressed.

Aerosol layer height from synergistic use of VIIRS and OMPS

NASA Astrophysics Data System (ADS)

Lee, J.; Hsu, N. Y. C.; Sayer, A. M.; Kim, W.; Seftor, C. J.

2017-12-01

This study presents an Aerosol Single-scattering albedo and Height Estimation (ASHE) algorithm, which retrieves the height of UV-absorbing aerosols by synergistically using the Visible Infrared Imaging Radiometer Suite (VIIRS) and the Ozone Mapping and Profiler Suite (OMPS). ASHE provides height information over a much broader area than ground-based or spaceborne lidar measurements by benefitting from the wide swaths of the two instruments used. As determination of single-scattering albedo (SSA) of the aerosol layer is the most critical part for the performance and coverage of ASHE, here we demonstrate three different strategies to constrain the SSA. First, ASHE is able to retrieve the SSA of UV-absorbing aerosols when Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) provides vertical profiles of the aerosol layer of interest. Second, Aerosol Robotic Network (AERONET) inversions can directly constrain the SSA of the aerosol layer when collocated with VIIRS or OMPS. Last, a SSA climatology from ASHE, AERONET, or other data sources can be used for large-scale, aged aerosol events, for which climatological SSA is well-known, at the cost of a slight decrease in retrieval accuracy. The same algorithm can be applied to measurements of similar type, such as those made by the Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI), for a long-term, consistent data record.

Stress-induced solid-state amorphization of nanocrystalline Ni and NiZr investigated by atomistic simulations

NASA Astrophysics Data System (ADS)

Meraj, Md.; Deng, Chuang; Pal, Snehanshu

2018-01-01

In this study, the feasibility of stress induced solid-state amorphization (SSA) of nanocrystalline (NC) Ni and NiZr alloys having ˜10 nm grain size has been investigated under constant tensile load (uniaxial and triaxial) via molecular dynamics simulations. In order to track the structural evaluation in both NC Ni and NiZr alloys during the SSA process, various types of analysis have been used, including simulated X-ray diffraction, centro-symmetry parameter, Voronoi cluster, common neighbor analysis, and radial distribution function. It is found that SSA in both NC Ni and NiZr alloys can only be achieved under triaxial loading conditions, and the hydrostatic tensile stress required for SSA is significantly lower when at. % Zr is increased in the NC NiZr alloy. Specifically, SSA in NC Ni and Ni-5 at. % Zr alloy was observed only when the temperature and hydrostatic tensile stress reached 800 K and 6 GPa, while SSA could occur in NC Ni-10 at. % Zr alloy under just 2 GPa of hydrostatic tensile stress at 300 K.

Comparison of different methods to retrieve optical-equivalent snow grain size in central Antarctica

NASA Astrophysics Data System (ADS)

Carlsen, Tim; Birnbaum, Gerit; Ehrlich, André; Freitag, Johannes; Heygster, Georg; Istomina, Larysa; Kipfstuhl, Sepp; Orsi, Anaïs; Schäfer, Michael; Wendisch, Manfred

2017-11-01

The optical-equivalent snow grain size affects the reflectivity of snow surfaces and, thus, the local surface energy budget in particular in polar regions. Therefore, the specific surface area (SSA), from which the optical snow grain size is derived, was observed for a 2-month period in central Antarctica (Kohnen research station) during austral summer 2013/14. The data were retrieved on the basis of ground-based spectral surface albedo measurements collected by the COmpact RAdiation measurement System (CORAS) and airborne observations with the Spectral Modular Airborne Radiation measurement sysTem (SMART). The snow grain size and pollution amount (SGSP) algorithm, originally developed to analyze spaceborne reflectance measurements by the MODerate Resolution Imaging Spectroradiometer (MODIS), was modified in order to reduce the impact of the solar zenith angle on the retrieval results and to cover measurements in overcast conditions. Spectral ratios of surface albedo at 1280 and 1100 nm wavelength were used to reduce the retrieval uncertainty. The retrieval was applied to the ground-based and airborne observations and validated against optical in situ observations of SSA utilizing an IceCube device. The SSA retrieved from CORAS observations varied between 27 and 89 m2 kg-1. Snowfall events caused distinct relative maxima of the SSA which were followed by a gradual decrease in SSA due to snow metamorphism and wind-induced transport of freshly fallen ice crystals. The ability of the modified algorithm to include measurements in overcast conditions improved the data coverage, in particular at times when precipitation events occurred and the SSA changed quickly. SSA retrieved from measurements with CORAS and MODIS agree with the in situ observations within the ranges given by the measurement uncertainties. However, SSA retrieved from the airborne SMART data slightly underestimated the ground-based results.

Summertime evolution of snow specific surface area close to the surface on the Antarctic Plateau

NASA Astrophysics Data System (ADS)

Libois, Q.; Picard, G.; Arnaud, L.; Dumont, M.; Lafaysse, M.; Morin, S.; Lefebvre, E.

2015-12-01

On the Antarctic Plateau, snow specific surface area (SSA) close to the surface shows complex variations at daily to seasonal scales which affect the surface albedo and in turn the surface energy budget of the ice sheet. While snow metamorphism, precipitation and strong wind events are known to drive SSA variations, usually in opposite ways, their relative contributions remain unclear. Here, a comprehensive set of SSA observations at Dome C is analysed with respect to meteorological conditions to assess the respective roles of these factors. The results show an average 2-to-3-fold SSA decrease from October to February in the topmost 10 cm in response to the increase of air temperature and absorption of solar radiation in the snowpack during spring and summer. Surface SSA is also characterized by significant daily to weekly variations due to the deposition of small crystals with SSA up to 100 m2 kg-1 onto the surface during snowfall and blowing snow events. To complement these field observations, the detailed snowpack model Crocus is used to simulate SSA, with the intent to further investigate the previously found correlation between interannual variability of summer SSA decrease and summer precipitation amount. To this end, some Crocus parameterizations have been adapted to Dome C conditions, and the model was forced by ERA-Interim reanalysis. It successfully matches the observations at daily to seasonal timescales, except for the few cases when snowfalls are not captured by the reanalysis. On the contrary, the interannual variability of summer SSA decrease is poorly simulated when compared to 14 years of microwave satellite data sensitive to the near-surface SSA. A simulation with disabled summer precipitation confirms the weak influence in the model of the precipitation on metamorphism, with only 6 % enhancement. However, we found that disabling strong wind events in the model is sufficient to reconciliate the simulations with the observations. This suggests that Crocus reproduces well the contributions of metamorphism and precipitation on surface SSA, but snow compaction by the wind might be overestimated in the model.

Summertime evolution of snow specific surface area close to the surface on the Antarctic Plateau

NASA Astrophysics Data System (ADS)

Libois, Q.; Picard, G.; Arnaud, L.; Dumont, M.; Lafaysse, M.; Morin, S.; Lefebvre, E.

2015-08-01

On the Antarctic Plateau, snow specific surface area (SSA) close to the surface shows complex variations at daily to seasonal scales which affect the surface albedo and in turn the surface energy budget of the ice sheet. While snow metamorphism, precipitation and strong wind events are known to drive SSA variations, usually in opposite ways, their relative contributions remain unclear. Here, a comprehensive set of SSA observations at Dome C is analysed with respect to meteorological conditions to assess the respective roles of these factors. The results show an average two-to-three-fold SSA decrease from October to February in the topmost 10 cm, in response to the increase of air temperature and absorption of solar radiation in the snowpack during spring and summer. Surface SSA is also characterised by significant daily to weekly variations, due to the deposition of small crystals with SSA up to 100 m2 kg-1 onto the surface during snowfall and blowing snow events. To complement these field observations, the detailed snowpack model Crocus is used to simulate SSA, with the intent to further investigate the previously found correlation between inter-annual variability of summer SSA decrease and summer precipitation amount. To this end, Crocus parameterizations have been adapted to Dome C conditions, and the model was forced by ERA-Interim reanalysis. It successfully matches the observations at daily to seasonal time scales, except for few cases when snowfalls are not captured by the reanalysis. On the contrary, the inter-annual variability of summer SSA decrease is poorly simulated when compared to 14 years of microwave satellite data sensititve to the near surface SSA. A simulation with disabled summer precipitation confirms the weak influence in the model of the precipitation on metamorphism, with only 6 % enhancement. However we found that disabling strong wind events in the model is sufficient to reconciliate the simulations with the observations. This suggests that Crocus reproduces well the contributions of metamorphism and precipitation on surface SSA, but that snow compaction by the wind might be overestimated in the model.

Generic Modeling of a Life Support System for Process Technology Comparison

NASA Technical Reports Server (NTRS)

Ferrall, J. F.; Seshan, P. K.; Rohatgi, N. K.; Ganapathi, G. B.

1993-01-01

This paper describes a simulation model called the Life Support Systems Analysis Simulation Tool (LiSSA-ST), the spreadsheet program called the Life Support Systems Analysis Trade Tool (LiSSA-TT), and the Generic Modular Flow Schematic (GMFS) modeling technique. Results of using the LiSSA-ST and the LiSSA-TT will be presented for comparing life support system and process technology options for a Lunar Base with a crew size of 4 and mission lengths of 90 and 600 days. System configurations to minimize the life support system weight and power are explored.

Snow specific surface area simulation using the one-layer snow model in the Canadian LAnd Surface Scheme (CLASS)

NASA Astrophysics Data System (ADS)

Roy, A.; Royer, A.; Montpetit, B.; Bartlett, P. A.; Langlois, A.

2012-12-01

Snow grain size is a key parameter for modeling microwave snow emission properties and the surface energy balance because of its influence on the snow albedo, thermal conductivity and diffusivity. A model of the specific surface area (SSA) of snow was implemented in the one-layer snow model in the Canadian LAnd Surface Scheme (CLASS) version 3.4. This offline multilayer model (CLASS-SSA) simulates the decrease of SSA based on snow age, snow temperature and the temperature gradient under dry snow conditions, whereas it considers the liquid water content for wet snow metamorphism. We compare the model with ground-based measurements from several sites (alpine, Arctic and sub-Arctic) with different types of snow. The model provides simulated SSA in good agreement with measurements with an overall point-to-point comparison RMSE of 8.1 m2 kg-1, and a RMSE of 4.9 m2 kg-1 for the snowpack average SSA. The model, however, is limited under wet conditions due to the single-layer nature of the CLASS model, leading to a single liquid water content value for the whole snowpack. The SSA simulations are of great interest for satellite passive microwave brightness temperature assimilations, snow mass balance retrievals and surface energy balance calculations with associated climate feedbacks.

Distributed sensor management for space situational awareness via a negotiation game

NASA Astrophysics Data System (ADS)

Jia, Bin; Shen, Dan; Pham, Khanh; Blasch, Erik; Chen, Genshe

2015-05-01

Space situational awareness (SSA) is critical to many space missions serving weather analysis, communications, and navigation. However, the number of sensors used in space situational awareness is limited which hinders collision avoidance prediction, debris assessment, and efficient routing. Hence, it is critical to use such sensor resources efficiently. In addition, it is desired to develop the SSA sensor management algorithm in a distributed manner. In this paper, a distributed sensor management approach using the negotiation game (NG-DSM) is proposed for the SSA. Specifically, the proposed negotiation game is played by each sensor and its neighboring sensors. The bargaining strategies are developed for each sensor based on negotiating for accurately tracking desired targets (e.g., satellite, debris, etc.) . The proposed NG-DSM method is tested in a scenario which includes eight space objects and three different sensor modalities which include a space based optical sensor, a ground radar, or a ground Electro-Optic sensor. The geometric relation between the sensor, the Sun, and the space object is also considered. The simulation results demonstrate the effectiveness of the proposed NG-DSM sensor management methods, which facilitates an application of multiple-sensor multiple-target tracking for space situational awareness.

Game-theoretic homological sensor resource management for SSA

NASA Astrophysics Data System (ADS)

Chin, Sang Peter

2009-05-01

We present a game-theoretic approach to Level 2/3/4 fusion for the purpose of Space Situational Awareness (SSA) along with prototypical SW implementation of this approach to demonstrate its effectiveness for possible future space operations. Our approach is based upon innovative techniques that we are developing to solve dynamic games and Nperson cooperative/non-cooperative games, as well as a new emerging homological sensing algorithms which we apply to control disparate network of space sensors in order to gain better SSA.

Two Simulated-Smog Atmospheres with Different Chemical Compositions Produce Contrasting Mutagenicity in Salmonella.

EPA Science Inventory

Ozone (O3), particulate matter (PM), and nitrogen dioxide (NO2) are criteria pollutants used to evaluate air quality. Using a 14.3-m3 Teflon-lined smog chamber with 120 UV bulbs to simulate solar radiation, we generated 2 simulated-smog atmospheres (SSA-1 & SSA-2) with differ...

Predicting Sepsis Risk Using the "Sniffer" Algorithm in the Electronic Medical Record.

PubMed

Olenick, Evelyn M; Zimbro, Kathie S; DʼLima, Gabrielle M; Ver Schneider, Patricia; Jones, Danielle

The Sepsis "Sniffer" Algorithm (SSA) has merit as a digital sepsis alert but should be considered an adjunct to versus an alternative for the Nurse Screening Tool (NST), given lower specificity and positive predictive value. The SSA reduced the risk of incorrectly categorizing patients at low risk for sepsis, detected sepsis high risk in half the time, and reduced redundant NST screens by 70% and manual screening hours by 64% to 72%. Preserving nurse hours expended on manual sepsis alerts may translate into time directed toward other patient priorities.

Management of hypertension at the community level in sub-Saharan Africa (SSA): towards a rational use of available resources.

PubMed

Twagirumukiza, M; Van Bortel, L M

2011-01-01

Hypertension is emerging in many developing nations as a leading cause of cardiovascular mortality, morbidity and disability in adults. In sub-Saharan African (SSA) countries it has specificities such as occurring in young and active adults, resulting in severe complications dominated by heart failure and taking place in limited-resource settings in which an individual's access to treatment (affordability) is very limited. Within this context of restrained economic conditions, the greatest gains for SSA in controlling the hypertension epidemic lie in its prevention. Attempts should be made to detect hypertensive patients early before irreversible organ damage becomes apparent, and to provide them with the best possible and affordable non-pharmacological and pharmacological treatment. Therefore, efforts should be made for detection and early management at the community level. In this context, a standardized algorithm of management can help in the rational use of available resources. Although many international and regional guidelines have been published, they cannot apply to SSA settings because the economy of the countries and affordability of the patients do not allow access to advocated treatment. In addition, none of them suggest a clear algorithm of management for limited-resource settings at the community level. In line with available data and analysing existing guidelines, a practical algorithm for management of hypertension at the community level, including treatment affordability, has been suggested in the present work.

Benchmarking the Algorithms to Detect Seasonal Signals Under Different Noise Conditions

NASA Astrophysics Data System (ADS)

Klos, A.; Bogusz, J.; Bos, M. S.

2017-12-01

Global Positioning System (GPS) position time series contain seasonal signals. Among the others, annual and semi-annual are the most powerful. Widely, these oscillations are modelled as curves with constant amplitudes, using the Weighted Least-Squares (WLS) algorithm. However, in reality, the seasonal signatures vary over time, as their geophysical causes are not constant. Different algorithms have been already used to cover this time-variability, as Wavelet Decomposition (WD), Singular Spectrum Analysis (SSA), Chebyshev Polynomial (CP) or Kalman Filter (KF). In this research, we employed 376 globally distributed GPS stations which time series contributed to the newest International Terrestrial Reference Frame (ITRF2014). We show that for c.a. 20% of stations the amplitudes of seasonal signal varies over time of more than 1.0 mm. Then, we compare the WD, SSA, CP and KF algorithms for a set of synthetic time series to quantify them under different noise conditions. We show that when variations of seasonal signals are ignored, the power-law character is biased towards flicker noise. The most reliable estimates of the variations were found to be given by SSA and KF. These methods also perform the best for other noise levels while WD, and to a lesser extend also CP, have trouble in separating the seasonal signal from the noise which leads to an underestimation in the spectral index of power-law noise of around 0.1. For real ITRF2014 GPS data we discovered, that SSA and KF are capable to model 49-84% and 77-90% of the variance of the true varying seasonal signals, respectively.

Retrieval of Aerosol Optical Properties from Ground-Based Remote Sensing Measurements: Aerosol Asymmetry Factor and Single Scattering Albedo

NASA Astrophysics Data System (ADS)

Qie, L.; Li, Z.; Li, L.; Li, K.; Li, D.; Xu, H.

2018-04-01

The Devaux-Vermeulen-Li method (DVL method) is a simple approach to retrieve aerosol optical parameters from the Sun-sky radiance measurements. This study inherited the previous works of retrieving aerosol single scattering albedo (SSA) and scattering phase function, the DVL method was modified to derive aerosol asymmetric factor (g). To assess the algorithm performance at various atmospheric aerosol conditions, retrievals from AERONET observations were implemented, and the results are compared with AERONET official products. The comparison shows that both the DVL SSA and g were well correlated with those of AERONET. The RMSD and the absolute value of MBD deviations between the SSAs are 0.025 and 0.015 respectively, well below the AERONET declared SSA uncertainty of 0.03 for all wavelengths. For asymmetry factor g, the RMSD deviations are smaller than 0.02 and the absolute values of MBDs smaller than 0.01 at 675, 870 and 1020 nm bands. Then, considering several factors probably affecting retrieval quality (i.e. the aerosol optical depth (AOD), the solar zenith angle, and the sky residual error, sphericity proportion and Ångström exponent), the deviations for SSA and g of these two algorithms were calculated at varying value intervals. Both the SSA and g deviations were found decrease with the AOD and the solar zenith angle, and increase with sky residual error. However, the deviations do not show clear sensitivity to the sphericity proportion and Ångström exponent. This indicated that the DVL algorithm is available for both large, non-spherical particles and spherical particles. The DVL results are suitable for the evaluation of aerosol direct radiative effects of different aerosol types.

Preliminary study of the space adaptation of the MELiSSA life support system

NASA Astrophysics Data System (ADS)

Mas-Albaigès, Joan L.; Duatis, Jordi; Podhajsky, Sandra; Guirado, Víctor; Poughon, Laurent

MELiSSA (Micro-Ecological Life Support System Alternative) is an European Space Agency (ESA) project focused on the development of a closed regenerative life support system to aid the development of technologies for future life support systems for long term manned planetary missions, e.g. a lunar base or missions to Mars. In order to understand the potential evolution of the MELiSSA concept towards its future use in the referred manned planetary mission context the MELiSSA Space Adaptation (MSA) activity has been undertaken. MSA's main objective is to model the different MELiSSA compartments using EcosimPro R , a specialized simulation tool for life support applications, in order to define a preliminary MELiSSA implementation for service in a man-tended lunar base scenario, with a four-member crew rotating in six-month increments, and performing the basic LSS functions of air revitalization, food production, and waste and water recycling. The MELiSSA EcosimPro R Model features a dedicated library for the different MELiSSA elements (bioreactors, greenhouse, crew, interconnecting elements, etc.). It is used to dimension the MELiSSA system in terms of major parameters like mass, volume and energy needs, evaluate the accuracy of the results and define the strategy for a progressive loop closure from the initial required performance (approx.100 The MELiSSA configuration(s) obtained through the EcosimPro R simulation are further analysed using the Advanced Life Support System Evaluation (ALISSE) metric, relying on mass, energy, efficiency, human risk, system reliability and crew time, for trade-off and optimization of results. The outcome of the MSA activity is, thus, a potential Life Support System architecture description, based on combined MELiSSA and other physico-chemical technologies, defining its expected performance, associated operational conditions and logistic needs.

Development of a computer-adaptive physical function instrument for Social Security Administration disability determination.

PubMed

Ni, Pengsheng; McDonough, Christine M; Jette, Alan M; Bogusz, Kara; Marfeo, Elizabeth E; Rasch, Elizabeth K; Brandt, Diane E; Meterko, Mark; Haley, Stephen M; Chan, Leighton

2013-09-01

To develop and test an instrument to assess physical function for Social Security Administration (SSA) disability programs, the SSA-Physical Function (SSA-PF) instrument. Item response theory (IRT) analyses were used to (1) create a calibrated item bank for each of the factors identified in prior factor analyses, (2) assess the fit of the items within each scale, (3) develop separate computer-adaptive testing (CAT) instruments for each scale, and (4) conduct initial psychometric testing. Cross-sectional data collection; IRT analyses; CAT simulation. Telephone and Internet survey. Two samples: SSA claimants (n=1017) and adults from the U.S. general population (n=999). None. Model fit statistics, correlation, and reliability coefficients. IRT analyses resulted in 5 unidimensional SSA-PF scales: Changing & Maintaining Body Position, Whole Body Mobility, Upper Body Function, Upper Extremity Fine Motor, and Wheelchair Mobility for a total of 102 items. High CAT accuracy was demonstrated by strong correlations between simulated CAT scores and those from the full item banks. On comparing the simulated CATs with the full item banks, very little loss of reliability or precision was noted, except at the lower and upper ranges of each scale. No difference in response patterns by age or sex was noted. The distributions of claimant scores were shifted to the lower end of each scale compared with those of a sample of U.S. adults. The SSA-PF instrument contributes important new methodology for measuring the physical function of adults applying to the SSA disability programs. Initial evaluation revealed that the SSA-PF instrument achieved considerable breadth of coverage in each content domain and demonstrated noteworthy psychometric properties. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Two Simulated-Smog Atmospheres with Different Chemical Compositions Produce Contrasting Mutagenicity in Salmonella**

EPA Science Inventory

Ozone (O3), particulate matter (PM), and nitrogen dioxide (NO2) are criteria pollutants used to evaluate air quality. Using EPA’s Mobile Reaction Chamber (MRC), we generated 2 simulated-smog atmospheres (SSA-1 & SSA-2) with different concentrations of these criteria pol...

Retrieval of Aerosol Microphysical Properties from AERONET Photo-Polarimetric Measurements. 2: A New Research Algorithm and Case Demonstration

NASA Technical Reports Server (NTRS)

Xu, Xiaoguang; Wang, Jun; Zeng, Jing; Spurr, Robert; Liu, Xiong; Dubovik, Oleg; Li, Li; Li, Zhengqiang; Mishchenko, Michael I.; Siniuk, Aliaksandr;

Scale Refinement and Initial Evaluation of a Behavioral Health Function Measurement Tool for Work Disability Evaluation

PubMed Central

Marfeo, Elizabeth E.; Ni, Pengsheng; Bogusz, Kara; Meterko, Mark; McDonough, Christine M.; Chan, Leighton; Rasch, Elizabeth K.; Brandt, Diane E.; Jette, Alan M.

2014-01-01

Objectives To use item response theory (IRT) data simulations to construct and perform initial psychometric testing of a newly developed instrument, the Social Security Administration Behavioral Health Function (SSA-BH) instrument, that aims to assess behavioral health functioning relevant to the context of work. Design Cross-sectional survey followed by item response theory (IRT) calibration data simulations Setting Community Participants A sample of individuals applying for SSA disability benefits, claimants (N=1015), and a normative comparative sample of US adults (N=1000) Interventions None. Main Outcome Measure Social Security Administration Behavioral Health Function (SSA-BH) measurement instrument Results Item response theory analyses supported the unidimensionality of four SSA-BH scales: Mood and Emotions (35 items), Self-Efficacy (23 items), Social Interactions (6 items), and Behavioral Control (15 items). All SSA-BH scales demonstrated strong psychometric properties including reliability, accuracy, and breadth of coverage. High correlations of the simulated 5- or 10- item CATs with the full item bank indicated robust ability of the CAT approach to comprehensively characterize behavioral health function along four distinct dimensions. Conclusions Initial testing and evaluation of the SSA-BH instrument demonstrated good accuracy, reliability, and content coverage along all four scales. Behavioral function profiles of SSA claimants were generated and compared to age and sex matched norms along four scales: Mood and Emotions, Behavioral Control, Social Interactions, and Self-Efficacy. Utilizing the CAT based approach offers the ability to collect standardized, comprehensive functional information about claimants in an efficient way, which may prove useful in the context of the SSA’s work disability programs. PMID:23542404

An adaptive multi-level simulation algorithm for stochastic biological systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lester, C., E-mail: lesterc@maths.ox.ac.uk; Giles, M. B.; Baker, R. E.

2015-01-14

Discrete-state, continuous-time Markov models are widely used in the modeling of biochemical reaction networks. Their complexity often precludes analytic solution, and we rely on stochastic simulation algorithms (SSA) to estimate system statistics. The Gillespie algorithm is exact, but computationally costly as it simulates every single reaction. As such, approximate stochastic simulation algorithms such as the tau-leap algorithm are often used. Potentially computationally more efficient, the system statistics generated suffer from significant bias unless tau is relatively small, in which case the computational time can be comparable to that of the Gillespie algorithm. The multi-level method [Anderson and Higham, “Multi-level Montemore » Carlo for continuous time Markov chains, with applications in biochemical kinetics,” SIAM Multiscale Model. Simul. 10(1), 146–179 (2012)] tackles this problem. A base estimator is computed using many (cheap) sample paths at low accuracy. The bias inherent in this estimator is then reduced using a number of corrections. Each correction term is estimated using a collection of paired sample paths where one path of each pair is generated at a higher accuracy compared to the other (and so more expensive). By sharing random variables between these paired paths, the variance of each correction estimator can be reduced. This renders the multi-level method very efficient as only a relatively small number of paired paths are required to calculate each correction term. In the original multi-level method, each sample path is simulated using the tau-leap algorithm with a fixed value of τ. This approach can result in poor performance when the reaction activity of a system changes substantially over the timescale of interest. By introducing a novel adaptive time-stepping approach where τ is chosen according to the stochastic behaviour of each sample path, we extend the applicability of the multi-level method to such cases. We demonstrate the efficiency of our method using a number of examples.« less

A graph-based semantic similarity measure for the gene ontology.

PubMed

Alvarez, Marco A; Yan, Changhui

2011-12-01

Existing methods for calculating semantic similarities between pairs of Gene Ontology (GO) terms and gene products often rely on external databases like Gene Ontology Annotation (GOA) that annotate gene products using the GO terms. This dependency leads to some limitations in real applications. Here, we present a semantic similarity algorithm (SSA), that relies exclusively on the GO. When calculating the semantic similarity between a pair of input GO terms, SSA takes into account the shortest path between them, the depth of their nearest common ancestor, and a novel similarity score calculated between the definitions of the involved GO terms. In our work, we use SSA to calculate semantic similarities between pairs of proteins by combining pairwise semantic similarities between the GO terms that annotate the involved proteins. The reliability of SSA was evaluated by comparing the resulting semantic similarities between proteins with the functional similarities between proteins derived from expert annotations or sequence similarity. Comparisons with existing state-of-the-art methods showed that SSA is highly competitive with the other methods. SSA provides a reliable measure for semantics similarity independent of external databases of functional-annotation observations.

Understanding Large-scale Structure in the SSA22 Protocluster Region Using Cosmological Simulations

NASA Astrophysics Data System (ADS)

Topping, Michael W.; Shapley, Alice E.; Steidel, Charles C.; Naoz, Smadar; Primack, Joel R.

2018-01-01

We investigate the nature and evolution of large-scale structure within the SSA22 protocluster region at z = 3.09 using cosmological simulations. A redshift histogram constructed from current spectroscopic observations of the SSA22 protocluster reveals two separate peaks at z = 3.065 (blue) and z = 3.095 (red). Based on these data, we report updated overdensity and mass calculations for the SSA22 protocluster. We find {δ }b,{gal}=4.8+/- 1.8 and {δ }r,{gal}=9.5+/- 2.0 for the blue and red peaks, respectively, and {δ }t,{gal}=7.6+/- 1.4 for the entire region. These overdensities correspond to masses of {M}b=(0.76+/- 0.17)× {10}15{h}-1 {M}ȯ , {M}r=(2.15+/- 0.32)× {10}15{h}-1 {M}ȯ , and {M}t=(3.19+/- 0.40)× {10}15{h}-1 {M}ȯ for the red, blue, and total peaks, respectively. We use the Small MultiDark Planck (SMDPL) simulation to identify comparably massive z∼ 3 protoclusters, and uncover the underlying structure and ultimate fate of the SSA22 protocluster. For this analysis, we construct mock redshift histograms for each simulated z∼ 3 protocluster, quantitatively comparing them with the observed SSA22 data. We find that the observed double-peaked structure in the SSA22 redshift histogram corresponds not to a single coalescing cluster, but rather the proximity of a ∼ {10}15{h}-1 {M}ȯ protocluster and at least one > {10}14{h}-1 {M}ȯ cluster progenitor. Such associations in the SMDPL simulation are easily understood within the framework of hierarchical clustering of dark matter halos. We finally find that the opportunity to observe such a phenomenon is incredibly rare, with an occurrence rate of 7.4{h}3 {{{Gpc}}}-3. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W.M. Keck Foundation.

Development of a Computer-Adaptive Physical Function Instrument for Social Security Administration Disability Determination

PubMed Central

Ni, Pengsheng; McDonough, Christine M.; Jette, Alan M.; Bogusz, Kara; Marfeo, Elizabeth E.; Rasch, Elizabeth K.; Brandt, Diane E.; Meterko, Mark; Chan, Leighton

2014-01-01

Objectives To develop and test an instrument to assess physical function (PF) for Social Security Administration (SSA) disability programs, the SSA-PF. Item Response Theory (IRT) analyses were used to 1) create a calibrated item bank for each of the factors identified in prior factor analyses, 2) assess the fit of the items within each scale, 3) develop separate Computer-Adaptive Test (CAT) instruments for each scale, and 4) conduct initial psychometric testing. Design Cross-sectional data collection; IRT analyses; CAT simulation. Setting Telephone and internet survey. Participants Two samples: 1,017 SSA claimants, and 999 adults from the US general population. Interventions None. Main Outcome Measure Model fit statistics, correlation and reliability coefficients, Results IRT analyses resulted in five unidimensional SSA-PF scales: Changing & Maintaining Body Position, Whole Body Mobility, Upper Body Function, Upper Extremity Fine Motor, and Wheelchair Mobility for a total of 102 items. High CAT accuracy was demonstrated by strong correlations between simulated CAT scores and those from the full item banks. Comparing the simulated CATs to the full item banks, very little loss of reliability or precision was noted, except at the lower and upper ranges of each scale. No difference in response patterns by age or sex was noted. The distributions of claimant scores were shifted to the lower end of each scale compared to those of a sample of US adults. Conclusions The SSA-PF instrument contributes important new methodology for measuring the physical function of adults applying to the SSA disability programs. Initial evaluation revealed that the SSA-PF instrument achieved considerable breadth of coverage in each content domain and demonstrated noteworthy psychometric properties. PMID:23578594

Hybrid ODE/SSA methods and the cell cycle model

NASA Astrophysics Data System (ADS)

Wang, S.; Chen, M.; Cao, Y.

2017-07-01

Stochastic effect in cellular systems has been an important topic in systems biology. Stochastic modeling and simulation methods are important tools to study stochastic effect. Given the low efficiency of stochastic simulation algorithms, the hybrid method, which combines an ordinary differential equation (ODE) system with a stochastic chemically reacting system, shows its unique advantages in the modeling and simulation of biochemical systems. The efficiency of hybrid method is usually limited by reactions in the stochastic subsystem, which are modeled and simulated using Gillespie's framework and frequently interrupt the integration of the ODE subsystem. In this paper we develop an efficient implementation approach for the hybrid method coupled with traditional ODE solvers. We also compare the efficiency of hybrid methods with three widely used ODE solvers RADAU5, DASSL, and DLSODAR. Numerical experiments with three biochemical models are presented. A detailed discussion is presented for the performances of three ODE solvers.

Constraints on Global Aerosol Types: Past, Present, and Near-Future

NASA Astrophysics Data System (ADS)

Kahn, Ralph

2014-05-01

Although the recent IPCC fifth assessment report (AR5) suggests that confidence in estimated direct aerosol radiative forcing (DARF) is high, indications are that there is little agreement among current climate models about the global distribution of aerosol single-scattering albedo (SSA). SSA must be associated with specific surface albedo and aerosol optical depth (AOD) values to calculate DARF with confidence, and global-scale constraints on aerosol type, including SSA, are poor at present. Yet, some constraints on aerosol type have been demonstrated for several satellite instruments, including the NASA Earth Observing System's Multi-angle Imaging SpectroRadiometer (MISR). The time-series of approximately once-weekly, global MISR observations has grown to about 14 years. The MISR capability amounts to three-to-five bins in particle size, two-to-four bins in SSA, and spherical vs. non-spherical particle distinctions, under good retrieval conditions. As the record of coincident, suborbital validation data has increased steadily, it has become progressively more feasible to assess and to improve the operational algorithm constraints on aerosol type. This presentation will discuss planned refinements to the MISR operational algorithm, and will highlight recent efforts at using MISR results to help better represent wildfire smoke, volcanic ash, and urban pollution in climate models.

Aeronet-based Microphysical and Optical Properties of Smoke-dominated Aerosol near Source Regions and Transported over Oceans, and Implications for Satellite Retrievals of Aerosol Optical Depth

NASA Technical Reports Server (NTRS)

Sayer, A. M.; Hsu, N. C.; Eck, T. F.; Smirnov, A.; Holben, B. N.

2013-01-01

Smoke aerosols from biomass burning are an important component of the global aerosol cycle. Analysis of Aerosol Robotic Network (AERONET) retrievals of size distribution and refractive index reveals variety between biomass burning aerosols in different global source regions, in terms of aerosol particle size and single scatter albedo (SSA). Case studies of smoke transported to coastal/island AERONET sites also mostly lie within the range of variability at near-source sites. Two broad families of aerosol properties are found, corresponding to sites dominated by boreal forest burning (larger, broader fine mode, with midvisible SSA 0.95), and those influenced by grass, shrub, or crop burning with additional forest contributions (smaller, narrower particles with SSA 0.88-0.9 in the midvisible). The strongest absorption is seen in southern African savanna at Mongu (Zambia), with average SSA 0.85 in the midvisible. These can serve as candidate sets of aerosol microphysicaloptical properties for use in satellite aerosol optical depth (AOD) retrieval algorithms. The models presently adopted by these algorithms over ocean are often insufficiently absorbing to represent these biomass burning aerosols. A corollary of this is an underestimate of AOD in smoke outflow regions, which has important consequences for applications of these satellite datasets.

Are we ready for Taenia solium cysticercosis elimination in sub-Saharan Africa?

PubMed

Johansen, Maria Vang; Trevisan, Chiara; Gabriël, Sarah; Magnussen, Pascal; Braae, Uffe Christian

2017-01-01

The World Health Organization announced in November 2014 at the fourth international meeting on 'the control of neglected zoonotic diseases - from advocacy to action', that intervention tools for eliminating Taenia solium taeniosis/cysticercosis (TSTC) are in place. The aim of this work was to elucidate theoretical outcomes of various control options suggested for TSTC elimination in sub-Saharan Africa (SSA) over a 4-year period. Our current knowledge regarding T. solium epidemiology and control primarily builds on studies from Latin America. A simple transmission model - built on data from Latin America - has been used to predict the effect of various interventions such as mass treatment of humans, vaccination and treatment of pigs, and health education of communities, potentially leading to change in bad practices and reducing transmission risks. Based on simulations of the transmission model, even a 4-year integrated One Health approach fails to eliminate TSTC from a small community and in all simulations, the prevalence of human taeniosis and porcine cysticercosis start to rise as soon as the programmes end. Our current knowledge regarding transmission and burden of TSTC in SSA is scarce and while claiming to be tool ready, the selection of diagnostic and surveillance tools, as well as the algorithms and stepwise approaches for control and elimination of TSTC remain major challenges.

Piezoelectric self-sensing actuator for active vibration control of motorized spindle based on adaptive signal separation

NASA Astrophysics Data System (ADS)

He, Ye; Chen, Xiaoan; Liu, Zhi; Qin, Yi

2018-06-01

The motorized spindle is the core component of CNC machine tools, and the vibration of it reduces the machining precision and service life of the machine tools. Owing to the fast response, large output force, and displacement of the piezoelectric stack, it is often used as the actuator in the active vibration control of the spindle. A piezoelectric self-sensing actuator (SSA) can reduce the cost of the active vibration control system and simplify the structure by eliminating the use of a sensor, because a SSA can have both actuating and sensing functions at the same time. The signal separation method of a SSA based on a bridge circuit is widely applied because of its simple principle and easy implementation. However, it is difficult to maintain dynamic balance of the circuit. Prior research has used adaptive algorithm to balance of the bridge circuit on the flexible beam dynamically, but those algorithms need no correlation between sensing and control voltage, which limit the applications of SSA in the vibration control of the rotor-bearing system. Here, the electromechanical coupling model of the piezoelectric stack is established, followed by establishment of the dynamic model of the spindle system. Next, a new adaptive signal separation method based on the bridge circuit is proposed, which can separate relative small sensing voltage from related mixed voltage adaptively. The experimental results show that when the self-sensing signal obtained from the proposed method is used as a displacement signal, the vibration of the motorized spindle can be suppressed effectively through a linear quadratic Gaussian (LQG) algorithm.

Sea salt emission, transport and influence on size-segregated nitrate simulation: a case study in northwestern Europe by WRF-Chem

NASA Astrophysics Data System (ADS)

Chen, Ying; Cheng, Yafang; Ma, Nan; Wolke, Ralf; Nordmann, Stephan; Schüttauf, Stephanie; Ran, Liang; Wehner, Birgit; Birmili, Wolfram; Denier van der Gon, Hugo A. C.; Mu, Qing; Barthel, Stefan; Spindler, Gerald; Stieger, Bastian; Müller, Konrad; Zheng, Guang-Jie; Pöschl, Ulrich; Su, Hang; Wiedensohler, Alfred

2016-09-01

Sea salt aerosol (SSA) is one of the major components of primary aerosols and has significant impact on the formation of secondary inorganic particles mass on a global scale. In this study, the fully online coupled WRF-Chem model was utilized to evaluate the SSA emission scheme and its influence on the nitrate simulation in a case study in Europe during 10-20 September 2013. Meteorological conditions near the surface, wind pattern and thermal stratification structure were well reproduced by the model. Nonetheless, the coarse-mode (PM1 - 10) particle mass concentration was substantially overestimated due to the overestimation of SSA and nitrate. Compared to filter measurements at four EMEP stations (coastal stations: Bilthoven, Kollumerwaard and Vredepeel; inland station: Melpitz), the model overestimated SSA concentrations by a factor of 8-20. We found that this overestimation was mainly caused by overestimated SSA emissions over the North Sea during 16-20 September. Over the coastal regions, SSA was injected into the continental free troposphere through an "aloft bridge" (about 500 to 1000 m above the ground), a result of the different thermodynamic properties and planetary boundary layer (PBL) structure between continental and marine regions. The injected SSA was further transported inland and mixed downward to the surface through downdraft and PBL turbulence. This process extended the influence of SSA to a larger downwind region, leading, for example, to an overestimation of SSA at Melpitz, Germany, by a factor of ˜ 20. As a result, the nitrate partitioning fraction (ratio between particulate nitrate and the summation of particulate nitrate and gas-phase nitric acid) increased by about 20 % for the coarse-mode nitrate due to the overestimation of SSA at Melpitz. However, no significant difference in the partitioning fraction for the fine-mode nitrate was found. About 140 % overestimation of the coarse-mode nitrate resulted from the influence of SSA at Melpitz. In contrast, the overestimation of SSA inhibited the nitrate particle formation in the fine mode by about 20 % because of the increased consumption of precursor by coarse-mode nitrate formation.

Retrieving the Height of Smoke and Dust Aerosols by Synergistic Use of Multiple Satellite Sensors

NASA Technical Reports Server (NTRS)

Lee, Jaehwa; Hsu, N. Christina; Bettenhausen, Corey; Sayer, Andrew M.; Seftor, Colin J.; Jeong, Myeong-Jae

2016-01-01

The Aerosol Single scattering albedo and Height Estimation (ASHE) algorithm was first introduced in Jeong and Hsu (2008) to provide aerosol layer height and single scattering albedo (SSA) for biomass burning smoke aerosols. By using multiple satellite sensors synergistically, ASHE can provide the height information over much broader areas than lidar observations alone. The complete ASHE algorithm uses aerosol data from MODIS or VIIRS, OMI or OMPS, and CALIOP. A simplified algorithm also exists that does not require CALIOP data as long as the SSA of the aerosol layer is provided by another source. Several updates have recently been made: inclusion of dust layers in the retrieval process, better determination of the input aerosol layer height from CALIOP, improvement in aerosol optical depth (AOD) for nonspherical dust, development of quality assurance (QA) procedure, etc.

Adaptive hybrid simulations for multiscale stochastic reaction networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hepp, Benjamin; Gupta, Ankit; Khammash, Mustafa

2015-01-21

The probability distribution describing the state of a Stochastic Reaction Network (SRN) evolves according to the Chemical Master Equation (CME). It is common to estimate its solution using Monte Carlo methods such as the Stochastic Simulation Algorithm (SSA). In many cases, these simulations can take an impractical amount of computational time. Therefore, many methods have been developed that approximate sample paths of the underlying stochastic process and estimate the solution of the CME. A prominent class of these methods include hybrid methods that partition the set of species and the set of reactions into discrete and continuous subsets. Such amore » partition separates the dynamics into a discrete and a continuous part. Simulating such a stochastic process can be computationally much easier than simulating the exact discrete stochastic process with SSA. Moreover, the quasi-stationary assumption to approximate the dynamics of fast subnetworks can be applied for certain classes of networks. However, as the dynamics of a SRN evolves, these partitions may have to be adapted during the simulation. We develop a hybrid method that approximates the solution of a CME by automatically partitioning the reactions and species sets into discrete and continuous components and applying the quasi-stationary assumption on identifiable fast subnetworks. Our method does not require any user intervention and it adapts to exploit the changing timescale separation between reactions and/or changing magnitudes of copy-numbers of constituent species. We demonstrate the efficiency of the proposed method by considering examples from systems biology and showing that very good approximations to the exact probability distributions can be achieved in significantly less computational time. This is especially the case for systems with oscillatory dynamics, where the system dynamics change considerably throughout the time-period of interest.« less

Adaptive hybrid simulations for multiscale stochastic reaction networks.

PubMed

Hepp, Benjamin; Gupta, Ankit; Khammash, Mustafa

2015-01-21

The probability distribution describing the state of a Stochastic Reaction Network (SRN) evolves according to the Chemical Master Equation (CME). It is common to estimate its solution using Monte Carlo methods such as the Stochastic Simulation Algorithm (SSA). In many cases, these simulations can take an impractical amount of computational time. Therefore, many methods have been developed that approximate sample paths of the underlying stochastic process and estimate the solution of the CME. A prominent class of these methods include hybrid methods that partition the set of species and the set of reactions into discrete and continuous subsets. Such a partition separates the dynamics into a discrete and a continuous part. Simulating such a stochastic process can be computationally much easier than simulating the exact discrete stochastic process with SSA. Moreover, the quasi-stationary assumption to approximate the dynamics of fast subnetworks can be applied for certain classes of networks. However, as the dynamics of a SRN evolves, these partitions may have to be adapted during the simulation. We develop a hybrid method that approximates the solution of a CME by automatically partitioning the reactions and species sets into discrete and continuous components and applying the quasi-stationary assumption on identifiable fast subnetworks. Our method does not require any user intervention and it adapts to exploit the changing timescale separation between reactions and/or changing magnitudes of copy-numbers of constituent species. We demonstrate the efficiency of the proposed method by considering examples from systems biology and showing that very good approximations to the exact probability distributions can be achieved in significantly less computational time. This is especially the case for systems with oscillatory dynamics, where the system dynamics change considerably throughout the time-period of interest.

A noisy chaotic neural network for solving combinatorial optimization problems: stochastic chaotic simulated annealing.

PubMed

Wang, Lipo; Li, Sa; Tian, Fuyu; Fu, Xiuju

2004-10-01

Recently Chen and Aihara have demonstrated both experimentally and mathematically that their chaotic simulated annealing (CSA) has better search ability for solving combinatorial optimization problems compared to both the Hopfield-Tank approach and stochastic simulated annealing (SSA). However, CSA may not find a globally optimal solution no matter how slowly annealing is carried out, because the chaotic dynamics are completely deterministic. In contrast, SSA tends to settle down to a global optimum if the temperature is reduced sufficiently slowly. Here we combine the best features of both SSA and CSA, thereby proposing a new approach for solving optimization problems, i.e., stochastic chaotic simulated annealing, by using a noisy chaotic neural network. We show the effectiveness of this new approach with two difficult combinatorial optimization problems, i.e., a traveling salesman problem and a channel assignment problem for cellular mobile communications.

Evolution of ESA's SSA Conjunction Prediction Service

NASA Astrophysics Data System (ADS)

Escobar, D.; Sancho, A. Tirado, J.; Agueda, A.; Martin, L.; Luque, F.; Fletcher, E.; Navarro, V.

2013-08-01

This paper presents the recent evolution of ESA's SSA Conjunction Prediction Service (CPS) as a result of an on-going activity in the Space Surveillance and Tracking (SST) Segment of ESA's Space Situational Awareness (SSA) Programme. The CPS is one of a number of precursor services being developed as part of the SST segment. It has been implemented as a service to provide external users with web-based access to conjunction information and designed with a service-oriented architecture. The paper encompasses the following topics: service functionality enhancements, integration with a live objects catalogue, all vs. all analyses supporting an operational concept based on low and high fidelity screenings, and finally conjunction detection and probability algorithms.

A High Fidelity Approach to Data Simulation for Space Situational Awareness Missions

NASA Astrophysics Data System (ADS)

Hagerty, S.; Ellis, H., Jr.

2016-09-01

Space Situational Awareness (SSA) is vital to maintaining our Space Superiority. A high fidelity, time-based simulation tool, PROXOR™ (Proximity Operations and Rendering), supports SSA by generating realistic mission scenarios including sensor frame data with corresponding truth. This is a unique and critical tool for supporting mission architecture studies, new capability (algorithm) development, current/future capability performance analysis, and mission performance prediction. PROXOR™ provides a flexible architecture for sensor and resident space object (RSO) orbital motion and attitude control that simulates SSA, rendezvous and proximity operations scenarios. The major elements of interest are based on the ability to accurately simulate all aspects of the RSO model, viewing geometry, imaging optics, sensor detector, and environmental conditions. These capabilities enhance the realism of mission scenario models and generated mission image data. As an input, PROXOR™ uses a library of 3-D satellite models containing 10+ satellites, including low-earth orbit (e.g., DMSP) and geostationary (e.g., Intelsat) spacecraft, where the spacecraft surface properties are those of actual materials and include Phong and Maxwell-Beard bidirectional reflectance distribution function (BRDF) coefficients for accurate radiometric modeling. We calculate the inertial attitude, the changing solar and Earth illumination angles of the satellite, and the viewing angles from the sensor as we propagate the RSO in its orbit. The synthetic satellite image is rendered at high resolution and aggregated to the focal plane resolution resulting in accurate radiometry even when the RSO is a point source. The sensor model includes optical effects from the imaging system [point spread function (PSF) includes aberrations, obscurations, support structures, defocus], detector effects (CCD blooming, left/right bias, fixed pattern noise, image persistence, shot noise, read noise, and quantization noise), and environmental effects (radiation hits with selectable angular distributions and 4-layer atmospheric turbulence model for ground based sensors). We have developed an accurate flash Light Detection and Ranging (LIDAR) model that supports reconstruction of 3-dimensional information on the RSO. PROXOR™ contains many important imaging effects such as intra-frame smear, realized by oversampling the image in time and capturing target motion and jitter during the integration time.

Sensitivity of Multiangle Imaging to the Optical and Microphysical Properties of Biomass Burning Aerosols

NASA Technical Reports Server (NTRS)

Chen, Wei-Ting; Kahn, Ralph A.; Nelson, David; Yau, Kevin; Seinfeld, John H.

2008-01-01

The treatment of biomass burning (BB) carbonaceous particles in the Multiangle Imaging SpectroRadiometer (MISR) Standard Aerosol Retrieval Algorithm is assessed, and algorithm refinements are suggested, based on a theoretical sensitivity analysis and comparisons with near-coincident AERONET measurements at representative BB sites. Over the natural ranges of BB aerosol microphysical and optical properties observed in past field campaigns, patterns of retrieved Aerosol Optical Depth (AOD), particle size, and single scattering albedo (SSA) are evaluated. On the basis of the theoretical analysis, assuming total column AOD of 0.2, over a dark, uniform surface, MISR can distinguish two to three groups in each of size and SSA, except when the assumed atmospheric particles are significantly absorbing (mid-visible SSA approx.0.84), or of medium sizes (mean radius approx.0.13 pin); sensitivity to absorbing, medium-large size particles increases considerably when the assumed column AOD is raised to 0.5. MISR Research Aerosol Retrievals confirm the theoretical results, based on coincident AERONET inversions under BB-dominated conditions. When BB is externally mixed with dust in the atmosphere, dust optical model and surface reflection uncertainties, along with spatial variability, contribute to differences between the Research Retrievals and AERONET. These results suggest specific refinements to the MISR Standard Aerosol Algorithm complement of component particles and mixtures. They also highlight the importance for satellite aerosol retrievals of surface reflectance characterization, with accuracies that can be difficult to achieve with coupled surface-aerosol algorithms in some higher AOD situations.

A computational study of liposome logic: towards cellular computing from the bottom up

PubMed Central

Smaldon, James; Romero-Campero, Francisco J.; Fernández Trillo, Francisco; Gheorghe, Marian; Alexander, Cameron

2010-01-01

In this paper we propose a new bottom-up approach to cellular computing, in which computational chemical processes are encapsulated within liposomes. This “liposome logic” approach (also called vesicle computing) makes use of supra-molecular chemistry constructs, e.g. protocells, chells, etc. as minimal cellular platforms to which logical functionality can be added. Modeling and simulations feature prominently in “top-down” synthetic biology, particularly in the specification, design and implementation of logic circuits through bacterial genome reengineering. The second contribution in this paper is the demonstration of a novel set of tools for the specification, modelling and analysis of “bottom-up” liposome logic. In particular, simulation and modelling techniques are used to analyse some example liposome logic designs, ranging from relatively simple NOT gates and NAND gates to SR-Latches, D Flip-Flops all the way to 3 bit ripple counters. The approach we propose consists of specifying, by means of P systems, gene regulatory network-like systems operating inside proto-membranes. This P systems specification can be automatically translated and executed through a multiscaled pipeline composed of dissipative particle dynamics (DPD) simulator and Gillespie’s stochastic simulation algorithm (SSA). Finally, model selection and analysis can be performed through a model checking phase. This is the first paper we are aware of that brings to bear formal specifications, DPD, SSA and model checking to the problem of modeling target computational functionality in protocells. Potential chemical routes for the laboratory implementation of these simulations are also discussed thus for the first time suggesting a potentially realistic physiochemical implementation for membrane computing from the bottom-up. PMID:21886681

An optimal-estimation-based aerosol retrieval algorithm using OMI near-UV observations

NASA Astrophysics Data System (ADS)

Jeong, U.; Kim, J.; Ahn, C.; Torres, O.; Liu, X.; Bhartia, P. K.; Spurr, R. J. D.; Haffner, D.; Chance, K.; Holben, B. N.

2016-01-01

An optimal-estimation(OE)-based aerosol retrieval algorithm using the OMI (Ozone Monitoring Instrument) near-ultraviolet observation was developed in this study. The OE-based algorithm has the merit of providing useful estimates of errors simultaneously with the inversion products. Furthermore, instead of using the traditional look-up tables for inversion, it performs online radiative transfer calculations with the VLIDORT (linearized pseudo-spherical vector discrete ordinate radiative transfer code) to eliminate interpolation errors and improve stability. The measurements and inversion products of the Distributed Regional Aerosol Gridded Observation Network campaign in northeast Asia (DRAGON NE-Asia 2012) were used to validate the retrieved aerosol optical thickness (AOT) and single scattering albedo (SSA). The retrieved AOT and SSA at 388 nm have a correlation with the Aerosol Robotic Network (AERONET) products that is comparable to or better than the correlation with the operational product during the campaign. The OE-based estimated error represented the variance of actual biases of AOT at 388 nm between the retrieval and AERONET measurements better than the operational error estimates. The forward model parameter errors were analyzed separately for both AOT and SSA retrievals. The surface reflectance at 388 nm, the imaginary part of the refractive index at 354 nm, and the number fine-mode fraction (FMF) were found to be the most important parameters affecting the retrieval accuracy of AOT, while FMF was the most important parameter for the SSA retrieval. The additional information provided with the retrievals, including the estimated error and degrees of freedom, is expected to be valuable for relevant studies. Detailed advantages of using the OE method were described and discussed in this paper.

An Optimal-Estimation-Based Aerosol Retrieval Algorithm Using OMI Near-UV Observations

NASA Technical Reports Server (NTRS)

Jeong, U; Kim, J.; Ahn, C.; Torres, O.; Liu, X.; Bhartia, P. K.; Spurr, R. J. D.; Haffner, D.; Chance, K.; Holben, B. N.

2016-01-01

An optimal-estimation(OE)-based aerosol retrieval algorithm using the OMI (Ozone Monitoring Instrument) near-ultraviolet observation was developed in this study. The OE-based algorithm has the merit of providing useful estimates of errors simultaneously with the inversion products. Furthermore, instead of using the traditional lookup tables for inversion, it performs online radiative transfer calculations with the VLIDORT (linearized pseudo-spherical vector discrete ordinate radiative transfer code) to eliminate interpolation errors and improve stability. The measurements and inversion products of the Distributed Regional Aerosol Gridded Observation Network campaign in northeast Asia (DRAGON NE-Asia 2012) were used to validate the retrieved aerosol optical thickness (AOT) and single scattering albedo (SSA). The retrieved AOT and SSA at 388 nm have a correlation with the Aerosol Robotic Network (AERONET) products that is comparable to or better than the correlation with the operational product during the campaign. The OEbased estimated error represented the variance of actual biases of AOT at 388 nm between the retrieval and AERONET measurements better than the operational error estimates. The forward model parameter errors were analyzed separately for both AOT and SSA retrievals. The surface reflectance at 388 nm, the imaginary part of the refractive index at 354 nm, and the number fine-mode fraction (FMF) were found to be the most important parameters affecting the retrieval accuracy of AOT, while FMF was the most important parameter for the SSA retrieval. The additional information provided with the retrievals, including the estimated error and degrees of freedom, is expected to be valuable for relevant studies. Detailed advantages of using the OE method were described and discussed in this paper.

Forecasting daily passenger traffic volumes in the Moscow metro

NASA Astrophysics Data System (ADS)

Ivanov, V. V.; Osetrov, E. S.

2018-01-01

In this paper we have developed a methodology for the medium-term prediction of daily volumes of passenger traffic in the Moscow metro. It includes three options for the forecast: (1) based on artificial neural networks (ANNs), (2) singular-spectral analysis implemented in the Caterpillar-SSA package, and (3) a combination of the ANN and Caterpillar-SSA approaches. The methods and algorithms allow the mediumterm forecasting of passenger traffic flows in the Moscow metro with reasonable accuracy.

Removal of EOG Artifacts from EEG Recordings Using Stationary Subspace Analysis

PubMed Central

Zeng, Hong; Song, Aiguo

2014-01-01

An effective approach is proposed in this paper to remove ocular artifacts from the raw EEG recording. The proposed approach first conducts the blind source separation on the raw EEG recording by the stationary subspace analysis (SSA) algorithm. Unlike the classic blind source separation algorithms, SSA is explicitly tailored to the understanding of distribution changes, where both the mean and the covariance matrix are taken into account. In addition, neither independency nor uncorrelation is required among the sources by SSA. Thereby, it can concentrate artifacts in fewer components than the representative blind source separation methods. Next, the components that are determined to be related to the ocular artifacts are projected back to be subtracted from EEG signals, producing the clean EEG data eventually. The experimental results on both the artificially contaminated EEG data and real EEG data have demonstrated the effectiveness of the proposed method, in particular for the cases where limited number of electrodes are used for the recording, as well as when the artifact contaminated signal is highly nonstationary and the underlying sources cannot be assumed to be independent or uncorrelated. PMID:24550696

Vertical variability of aerosol single-scattering albedo and equivalent black carbon concentration based on in-situ and remote sensing techniques during the iAREA campaigns in Ny-Ålesund

NASA Astrophysics Data System (ADS)

Markowicz, K. M.; Ritter, C.; Lisok, J.; Makuch, P.; Stachlewska, I. S.; Cappelletti, D.; Mazzola, M.; Chilinski, M. T.

2017-09-01

This work presents a methodology for obtaining vertical profiles of aerosol single scattering properties based on a combination of different measurement techniques. The presented data were obtained under the iAREA (Impact of absorbing aerosols on radiative forcing in the European Arctic) campaigns conducted in Ny-Ålesund (Spitsbergen) during the spring seasons of 2015-2017. The retrieval uses in-situ observations of black carbon concentration and absorption coefficient measured by a micro-aethalometer AE-51 mounted onboard a tethered balloon, as well as remote sensing data obtained from sun photometer and lidar measurements. From a combination of the balloon-borne in-situ and the lidar data, we derived profiles of single scattering albedo (SSA) as well as absorption, extinction, and aerosol number concentration. Results have been obtained in an altitude range from about 400 m up to 1600 m a.s.l. and for cases with increased aerosol load during the Arctic haze seasons of 2015 and 2016. The main results consist of the observation of increasing values of equivalent black carbon (EBC) and absorption coefficient with altitude, and the opposite trend for aerosol concentration for particles larger than 0.3 μm. SSA was retrieved with the use of lidar Raman and Klett algorithms for both 532 and 880 nm wavelengths. In most profiles, SSA shows relatively high temporal and altitude variability. Vertical variability of SSA computed from both methods is consistent; however, some discrepancy is related to Raman retrieval uncertainty and absorption coefficient estimation from AE-51. Typically, very low EBC concentration in Ny-Ålesund leads to large error in the absorbing coefficient. However, SSA uncertainty for both Raman and Klett algorithms seems to be reasonable, e.g. SSA of 0.98 and 0.95 relate to an error of ±0.01 and ± 0.025, respectively.

Factors for inconsistent aerosol single scattering albedo between SKYNET and AERONET

NASA Astrophysics Data System (ADS)

Khatri, P.; Takamura, T.; Nakajima, T.; Estellés, V.; Irie, H.; Kuze, H.; Campanelli, M.; Sinyuk, A.; Lee, S.-M.; Sohn, B. J.; Pandithurai, G.; Kim, S.-W.; Yoon, S. C.; Martinez-Lozano, J. A.; Hashimoto, M.; Devara, P. C. S.; Manago, N.

2016-02-01

SKYNET and Aerosol Robotic Network (AERONET) retrieved aerosol single scattering albedo (SSA) values of four sites, Chiba (Japan), Pune (India), Valencia (Spain), and Seoul (Korea), were compared to understand the factors behind often noted large SSA differences between them. SKYNET and AERONET algorithms are found to produce nearly same SSAs for similarity in input data, suggesting that SSA differences between them are primarily due to quality of input data due to different calibration and/or observation protocols as well as difference in quality assurance criteria. The most plausible reason for high SSAs in SKYNET is found to be underestimated calibration constant for sky radiance (ΔΩ). The disk scan method (scan area: 1° × 1° area of solar disk) of SKYNET is noted to produce stable wavelength-dependent ΔΩ values in comparison to those determined from the integrating sphere used by AERONET to calibrate sky radiance. Aerosol optical thickness (AOT) difference between them can be the next important factor for their SSA difference, if AOTs between them are not consistent. Inconsistent values of surface albedo while analyzing data of SKYNET and AERONET can also bring SSA difference between them, but the effect of surface albedo is secondary. The aerosol nonsphericity effect is found to be less important for SSA difference between these two networks.

Simulation of the MELiSSA closed loop system as a tool to define its integration strategy

NASA Astrophysics Data System (ADS)

Poughon, Laurent; Farges, Berangere; Dussap, Claude-Gilles; Godia, Francesc; Lasseur, Christophe

Inspired from a terrestrial ecosystem, MELiSSA (Micro Ecological Life Support System Alternative) is a project of closed life support system future long-term manned missions (Moon and Mars bases). Started on ESA in 1989, this 5 compartments concept has evolved following a mechanistic engineering approach for acquiring both theoretical and technical knowledge. In its current state of development the project can now start to demonstrate the MELiSSA loop concept at a pilot scale. Thus an integration strategy for a MELiSSA Pilot Plant (MPP) was defined, describing the different phases for tests and connections between compartments. The integration steps should be started in 2008 and be completed with a complete operational loop in 2015, which final objective is to achieve a closed liquid and gas loop with 100 Although the integration logic could start with the most advanced processes in terms of knowledge and hardware development, this logic needs to be completed by high politic of simulation. Thanks to this simulation exercise, the effective demonstrations of each independent process and its progressive coupling with others will be performed in operational conditions as close as possible to the final configuration. The theoretical approach described in this paper is based on mass balance models of each of the MELiSSA biological compartments which are used to simulate each integration step and the complete MPP loop itself. These simulations will help to identify criticalities of each integration steps and to check the consistencies between objectives, flows, recycling efficiencies and sizing of the pilot reactors. A MPP scenario compatible with the current knowledge of the operation of the pilot reactors was investigated and the theoretical performances of the system compared to the objectives of the MPP. From this scenario the most important milestone steps in the integration are highlighted and their behaviour can be simulated.

Heimdall System for MSSS Sensor Tasking

NASA Astrophysics Data System (ADS)

Herz, A.; Jones, B.; Herz, E.; George, D.; Axelrad, P.; Gehly, S.

In Norse Mythology, Heimdall uses his foreknowledge and keen eyesight to keep watch for disaster from his home near the Rainbow Bridge. Orbit Logic and the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado (CU) have developed the Heimdall System to schedule observations of known and uncharacterized objects and search for new objects from the Maui Space Surveillance Site. Heimdall addresses the current need for automated and optimized SSA sensor tasking driven by factors associated with improved space object catalog maintenance. Orbit Logic and CU developed an initial baseline prototype SSA sensor tasking capability for select sensors at the Maui Space Surveillance Site (MSSS) using STK and STK Scheduler, and then added a new Track Prioritization Component for FiSST-inspired computations for predicted Information Gain and Probability of Detection, and a new SSA-specific Figure-of-Merit (FOM) for optimized SSA sensor tasking. While the baseline prototype addresses automation and some of the multi-sensor tasking optimization, the SSA-improved prototype addresses all of the key elements required for improved tasking leading to enhanced object catalog maintenance. The Heimdall proof-of-concept was demonstrated for MSSS SSA sensor tasking for a 24 hour period to attempt observations of all operational satellites in the unclassified NORAD catalog, observe a small set of high priority GEO targets every 30 minutes, make a sky survey of the GEO belt region accessible to MSSS sensors, and observe particular GEO regions that have a high probability of finding new objects with any excess sensor time. This Heimdall prototype software paves the way for further R&D that will integrate this technology into the MSSS systems for operational scheduling, improve the software's scalability, and further tune and enhance schedule optimization. The Heimdall software for SSA sensor tasking provides greatly improved performance over manual tasking, improved coordinated sensor usage, and tasking schedules driven by catalog improvement goals (reduced overall covariance, etc.). The improved performance also enables more responsive sensor tasking to address external events, newly detected objects, newly detected object activity, and sensor anomalies. Instead of having to wait until the next day's scheduling phase, events can be addressed with new tasking schedules immediately (within seconds or minutes). Perhaps the most important benefit is improved SSA based on an overall improvement to the quality of the space catalog. By driving sensor tasking and scheduling based on predicted Information Gain and other relevant factors, better decisions are made in the application of available sensor resources, leading to an improved catalog and better information about the objects of most interest. The Heimdall software solution provides a configurable, automated system to improve sensor tasking efficiency and responsiveness for SSA applications. The FISST algorithms for Track Prioritization, SSA specific task and resource attributes, Scheduler algorithms, and configurable SSA-specific Figure-of-Merit together provide optimized and tunable scheduling for the Maui Space Surveillance Site and possibly other sites and organizations across the U.S. military and for allies around the world.

A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source

NASA Technical Reports Server (NTRS)

Eck, T. F.; Holben, B. N.; Reid, J. S.; Mukelabai, M. M.; Piketh, S. J.; Torres, O.; Jethva, H. T.; Hyer, E. J.; Ward, D. E.; Dubovik, O.;

A New Hybrid-Multiscale SSA Prediction of Non-Stationary Time Series

NASA Astrophysics Data System (ADS)

Ghanbarzadeh, Mitra; Aminghafari, Mina

2016-02-01

Singular spectral analysis (SSA) is a non-parametric method used in the prediction of non-stationary time series. It has two parameters, which are difficult to determine and very sensitive to their values. Since, SSA is a deterministic-based method, it does not give good results when the time series is contaminated with a high noise level and correlated noise. Therefore, we introduce a novel method to handle these problems. It is based on the prediction of non-decimated wavelet (NDW) signals by SSA and then, prediction of residuals by wavelet regression. The advantages of our method are the automatic determination of parameters and taking account of the stochastic structure of time series. As shown through the simulated and real data, we obtain better results than SSA, a non-parametric wavelet regression method and Holt-Winters method.

Effects of data assimilation on the global aerosol key optical properties simulations

NASA Astrophysics Data System (ADS)

Yin, Xiaomei; Dai, Tie; Schutgens, Nick A. J.; Goto, Daisuke; Nakajima, Teruyuki; Shi, Guangyu

2016-09-01

We present the one month results of global aerosol optical properties for April 2006, using the Spectral Radiation Transport Model for Aerosol Species (SPRINTARS) coupled with the Non-hydrostatic ICosahedral Atmospheric Model (NICAM), by assimilating Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) with Local Ensemble Transform Kalman Filter (LETKF). The simulated AOD, Ångström Exponent (AE) and single scattering albedo (SSA) are validated by independent Aerosol Robotic Network (AERONET) observations over the global sites. The data assimilation has the strongest positive effect on the AOD simulation and slight positive influences on the AE and SSA simulations. For the time-averaged globally spatial distribution, the data assimilation increases the model skill score (S) of AOD, AE, and SSA from 0.55, 0.92, and 0.75 to 0.79, 0.94, and 0.80, respectively. Over the North Africa (NAF) and Middle East region where the aerosol composition is simple (mainly dust), the simulated AODs are best improved by the data assimilation, indicating the assimilation correctly modifies the wrong dust burdens caused by the uncertainties of the dust emission parameterization. Assimilation also improves the simulation of the temporal variations of the aerosol optical properties over the AERONET sites, with improved S at 60 (62%), 45 (55%) and 11 (50%) of 97, 82 and 22 sites for AOD, AE and SSA. By analyzing AOD and AE at five selected sites with best S improvement, this study further indicates that the assimilation can reproduce short duration events and ratios between fine and coarse aerosols more accurately.

Development of a remote sensing algorithm to retrieve atmospheric aerosol properties using multiwavelength and multipixel information

NASA Astrophysics Data System (ADS)

Hashimoto, Makiko; Nakajima, Teruyuki

2017-06-01

We developed a satellite remote sensing algorithm to retrieve the aerosol optical properties using satellite-received radiances for multiple wavelengths and pixels. Our algorithm utilizes spatial inhomogeneity of surface reflectance to retrieve aerosol properties, and the main target is urban aerosols. This algorithm can simultaneously retrieve aerosol optical thicknesses (AOT) for fine- and coarse-mode aerosols, soot volume fraction in fine-mode aerosols (SF), and surface reflectance over heterogeneous surfaces such as urban areas that are difficult to obtain by conventional pixel-by-pixel methods. We applied this algorithm to radiances measured by the Greenhouse Gases Observing Satellite/Thermal and Near Infrared Sensor for Carbon Observations-Cloud and Aerosol Image (GOSAT/TANSO-CAI) at four wavelengths and were able to retrieve the aerosol parameters in several urban regions and other surface types. A comparison of the retrieved AOTs with those from the Aerosol Robotic Network (AERONET) indicated retrieval accuracy within ±0.077 on average. It was also found that the column-averaged SF and the aerosol single scattering albedo (SSA) underwent seasonal changes as consistent with the ground surface measurements of SSA and black carbon at Beijing, China.

Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

NASA Astrophysics Data System (ADS)

Kecorius, Simonas; Ma, Nan; Teich, Monique; van Pinxteren, Dominik; Zhang, Shenglan; Gröβ, Johannes; Spindler, Gerald; Müller, Konrad; Iinuma, Yoshiteru; Hu, Min; Herrmann, Hartmut; Wiedensohler, Alfred

2017-09-01

Particulate emissions from crop residue burning decrease the air quality as well as influence aerosol radiative properties on a regional scale. The North China Plain (NCP) is known for the large scale biomass burning (BB) of field residues, which often results in heavy haze pollution episodes across the region. We have been able to capture a unique BB episode during the international CAREBeijing-NCP intensive field campaign in Wangdu in the NCP (38.6°N, 115.2°E) from June to July 2014. It was found that aerosol particles originating from this BB event showed a significantly different mixing state compared with clean and non-BB pollution episodes. BB originated particles showed a narrower probability density function (PDF) of shrink factor (SF). And the maximum was found at shrink factor of 0.6, which is higher than in other episodes. The non-volatile particle number fraction during the BB episode decreased to 3% and was the lowest measured value compared to all other predefined episodes. To evaluate the influence of particle mixing state on aerosol single scattering albedo (SSA), SSA at different RHs was simulated using the measured aerosol physical-chemical properties. The differences between the calculated SSA for biomass burning, clean and pollution episodes are significant, meaning that the variation of SSA in different pollution conditions needs to be considered in the evaluation of aerosol direct radiative effects in the NCP. And the calculated SSA was found to be quite sensitive on the mixing state of BC, especially at low-RH condition. The simulated SSA was also compared with the measured values. For all the three predefined episodes, the measured SSA are very close to the calculated ones with assumed mixing states of homogeneously internal and core-shell internal mixing, indicating that both of the conception models are appropriate for the calculation of ambient SSA in the NCP.

A Laboratory Experiment for the Statistical Evaluation of Aerosol Retrieval (STEAR) Algorithms

NASA Astrophysics Data System (ADS)

Schuster, G. L.; Espinosa, R.; Ziemba, L. D.; Beyersdorf, A. J.; Rocha Lima, A.; Anderson, B. E.; Martins, J. V.; Dubovik, O.; Ducos, F.; Fuertes, D.; Lapyonok, T.; Shook, M.; Derimian, Y.; Moore, R.

2016-12-01

We have developed a method for validating Aerosol Robotic Network (AERONET) retrieval algorithms by mimicking atmospheric extinction and radiance measurements in a laboratory experiment. This enables radiometric retrievals that utilize the same sampling volumes, relative humidities, and particle size ranges as observed by other in situ instrumentation in the experiment. We utilize three Cavity Attenuated Phase Shift (CAPS) monitors for extinction and UMBC's three-wavelength Polarized Imaging Nephelometer (PI-Neph) for angular scattering measurements. We subsample the PI-Neph radiance measurements to angles that correspond to AERONET almucantar scans, with solar zenith angles ranging from 50 to 77 degrees. These measurements are then used as input to the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm, which retrieves size distributions, complex refractive indices, single-scatter albedos (SSA), and lidar ratios for the in situ samples. We obtained retrievals with residuals R < 10% for 100 samples. The samples that we tested include Arizona Test Dust, Arginotec NX, Senegal clay, Israel clay, montmorillonite, hematite, goethite, volcanic ash, ammonium nitrate, ammonium sulfate, and fullerene soot. Samples were alternately dried or humidified, and size distributions were limited to diameters of 1.0 or 2.5 um by using a cyclone. The SSA at 532 nm for these samples ranged from 0.59 to 1.00 when computed with CAPS extinction and PSAP absorption measurements. The GRASP retrieval provided SSAs that are highly correlated with the in situ SSAs, and the correlation coefficients ranged from 0.955 to 0.976, depending upon the simulated solar zenith angle. The GRASP SSAs exhibited an average absolute bias of +0.023 +/-0.01 with respect to the extinction and absorption measurements for the entire dataset. Although our apparatus was not capable of measuring backscatter lidar ratio, we did measure bistatic lidar ratios at a scattering angle of 173 deg. The GRASP bistatic lidar ratios had correlations of 0.488 to 0.735 (depending upon simulated SZA) with respect to in situ measurements, positive relative biases of 6-10%, and average absolute biases of 4.0-6.6 sr. We also compared the GRASP size distributions to aerodynamic particle size measurements.

Application of higher order SVD to vibration-based system identification and damage detection

NASA Astrophysics Data System (ADS)

Chao, Shu-Hsien; Loh, Chin-Hsiung; Weng, Jian-Huang

2012-04-01

Singular value decomposition (SVD) is a powerful linear algebra tool. It is widely used in many different signal processing methods, such principal component analysis (PCA), singular spectrum analysis (SSA), frequency domain decomposition (FDD), subspace identification and stochastic subspace identification method ( SI and SSI ). In each case, the data is arranged appropriately in matrix form and SVD is used to extract the feature of the data set. In this study three different algorithms on signal processing and system identification are proposed: SSA, SSI-COV and SSI-DATA. Based on the extracted subspace and null-space from SVD of data matrix, damage detection algorithms can be developed. The proposed algorithm is used to process the shaking table test data of the 6-story steel frame. Features contained in the vibration data are extracted by the proposed method. Damage detection can then be investigated from the test data of the frame structure through subspace-based and nullspace-based damage indices.

A Novel approach for predicting monthly water demand by combining singular spectrum analysis with neural networks

NASA Astrophysics Data System (ADS)

Zubaidi, Salah L.; Dooley, Jayne; Alkhaddar, Rafid M.; Abdellatif, Mawada; Al-Bugharbee, Hussein; Ortega-Martorell, Sandra

2018-06-01

Valid and dependable water demand prediction is a major element of the effective and sustainable expansion of municipal water infrastructures. This study provides a novel approach to quantifying water demand through the assessment of climatic factors, using a combination of a pretreatment signal technique, a hybrid particle swarm optimisation algorithm and an artificial neural network (PSO-ANN). The Singular Spectrum Analysis (SSA) technique was adopted to decompose and reconstruct water consumption in relation to six weather variables, to create a seasonal and stochastic time series. The results revealed that SSA is a powerful technique, capable of decomposing the original time series into many independent components including trend, oscillatory behaviours and noise. In addition, the PSO-ANN algorithm was shown to be a reliable prediction model, outperforming the hybrid Backtracking Search Algorithm BSA-ANN in terms of fitness function (RMSE). The findings of this study also support the view that water demand is driven by climatological variables.

Mechanisms of stochastic focusing and defocusing in biological reaction networks: insight from accurate chemical master equation (ACME) solutions.

PubMed

Gursoy, Gamze; Terebus, Anna; Youfang Cao; Jie Liang

2016-08-01

Stochasticity plays important roles in regulation of biochemical reaction networks when the copy numbers of molecular species are small. Studies based on Stochastic Simulation Algorithm (SSA) has shown that a basic reaction system can display stochastic focusing (SF) by increasing the sensitivity of the network as a result of the signal noise. Although SSA has been widely used to study stochastic networks, it is ineffective in examining rare events and this becomes a significant issue when the tails of probability distributions are relevant as is the case of SF. Here we use the ACME method to solve the exact solution of the discrete Chemical Master Equations and to study a network where SF was reported. We showed that the level of SF depends on the degree of the fluctuations of signal molecule. We discovered that signaling noise under certain conditions in the same reaction network can lead to a decrease in the system sensitivities, thus the network can experience stochastic defocusing. These results highlight the fundamental role of stochasticity in biological reaction networks and the need for exact computation of probability landscape of the molecules in the system.

Time Series Imputation via L1 Norm-Based Singular Spectrum Analysis

NASA Astrophysics Data System (ADS)

Kalantari, Mahdi; Yarmohammadi, Masoud; Hassani, Hossein; Silva, Emmanuel Sirimal

Missing values in time series data is a well-known and important problem which many researchers have studied extensively in various fields. In this paper, a new nonparametric approach for missing value imputation in time series is proposed. The main novelty of this research is applying the L1 norm-based version of Singular Spectrum Analysis (SSA), namely L1-SSA which is robust against outliers. The performance of the new imputation method has been compared with many other established methods. The comparison is done by applying them to various real and simulated time series. The obtained results confirm that the SSA-based methods, especially L1-SSA can provide better imputation in comparison to other methods.

Application of Artificial Neural Networks and Singular-Spectral Analysis in Forecasting the Daily Traffic in the Moscow Metro

NASA Astrophysics Data System (ADS)

Ivanov, Victor; Osetrov, Evgenii

2018-02-01

In this paper, we investigate the possibility of applying various approaches to solving the problem of medium-term forecasting of daily passenger traffic volumes in the Moscow metro (MM): 1) on the basis of artificial neural networks (ANN); 2) using the singular-spectral analysis implemented in the package "Caterpillar"-SSA; 3) sharing the ANN and the "Caterpillar"-SSA approach. We demonstrate that the developed methods and algorithms allow us to conduct medium-term forecasting of passenger traffic in the MM with reasonable accuracy.

Options for diabetes management in sub-Saharan Africa with an electronic medical record system.

PubMed

Kouematchoua Tchuitcheu, G; Rienhoff, O

2011-01-01

An increase of diabetes prevalence of up to 80% is predicted in sub-Saharan Africa (SSA) by 2025 exceeding the worldwide 55%. Mortality rates of diabetes and HIV/AIDS are similar. Diabetes shares several common factors with HIV/AIDS and multidrug-resistant tuberculosis (MDR-TB). The latter two health problems have been efficiently managed by an open source electronic medical record system (EMRS) in Latin America. Therefore a similar solution for diabetes in SSA could be extremely helpful. The aim was to design and validate a conceptual model for an EMRS to improve diabetes management in SSA making use of the HIV and TB experience. A review of the literature addressed diabetes care and management in SSA as well as existing examples of information and communication technology (ICT) use in SSA. Based on a need assessment conducted in SSA a conceptual model based on the traditionally structured healthcare system in SSA was mapped into a three-layer structure. Application modules were derived and a demonstrator programmed based on an open source EMRS. Then the approach was validated by SSA experts. A conceptual model could be specified and validated which enhances a problem-oriented approach to diabetes management processes. The prototyp EMRS demonstrates options for a patient portal and simulation tools for education of health professional and patients in SSA. It is possible to find IT solutions for diabetes care in SSA which follow the same efficiency concepts as HIV or TB modules in Latin America. The local efficiency and sustainability of the solution will, however, depend on training and changes in work behavior.

STOCHSIMGPU: parallel stochastic simulation for the Systems Biology Toolbox 2 for MATLAB.

PubMed

Klingbeil, Guido; Erban, Radek; Giles, Mike; Maini, Philip K

2011-04-15

The importance of stochasticity in biological systems is becoming increasingly recognized and the computational cost of biologically realistic stochastic simulations urgently requires development of efficient software. We present a new software tool STOCHSIMGPU that exploits graphics processing units (GPUs) for parallel stochastic simulations of biological/chemical reaction systems and show that significant gains in efficiency can be made. It is integrated into MATLAB and works with the Systems Biology Toolbox 2 (SBTOOLBOX2) for MATLAB. The GPU-based parallel implementation of the Gillespie stochastic simulation algorithm (SSA), the logarithmic direct method (LDM) and the next reaction method (NRM) is approximately 85 times faster than the sequential implementation of the NRM on a central processing unit (CPU). Using our software does not require any changes to the user's models, since it acts as a direct replacement of the stochastic simulation software of the SBTOOLBOX2. The software is open source under the GPL v3 and available at http://www.maths.ox.ac.uk/cmb/STOCHSIMGPU. The web site also contains supplementary information. klingbeil@maths.ox.ac.uk Supplementary data are available at Bioinformatics online.

GATE simulation of a new design of pinhole SPECT system for small animal brain imaging

NASA Astrophysics Data System (ADS)

Uzun Ozsahin, D.; Bläckberg, L.; El Fakhri, G.; Sabet, H.

2017-01-01

Small animal SPECT imaging has gained an increased interest over the past decade since it is an excellent tool for developing new drugs and tracers. Therefore, there is a huge effort on the development of cost-effective SPECT detectors with high capabilities. The aim of this study is to simulate the performance characteristics of new designs for a cost effective, stationary SPECT system dedicated to small animal imaging with a focus on mice brain. The conceptual design of this SPECT system platform, Stationary Small Animal SSA-SPECT, is to use many pixelated CsI:TI detector modules with 0.4 mm × 0.4 mm pixels in order to achieve excellent intrinsic detector resolution where each module is backed by a single pinhole collimator with 0.3 mm hole diameter. In this work, we present the simulation results of four variations of the SSA-SPECT platform where the number of detector modules and FOV size is varied while keeping the detector size and collimator hole size constant. Using the NEMA NU-4 protocol, we performed spatial resolution, sensitivity, image quality simulations followed by a Derenzo-like phantom evaluation. The results suggest that all four SSA-SPECT systems can provide better than 0.063% system sensitivity and < 1.5 mm FWHM spatial resolution without resolution recovery or other correction techniques. Specifically, SSA-SPECT-1 showed a system sensitivity of 0.09% in combination with 1.1 mm FWHM spatial resolution.

The OrbitOutlook Data Archive

NASA Astrophysics Data System (ADS)

Czajkowski, M.; Shilliday, A.; LoFaso, N.; Dipon, A.; Van Brackle, D.

2016-09-01

In this paper, we describe and depict the Defense Advanced Research Projects Agency (DARPA)'s OrbitOutlook Data Archive (OODA) architecture. OODA is the infrastructure that DARPA's OrbitOutlook program has developed to integrate diverse data from various academic, commercial, government, and amateur space situational awareness (SSA) telescopes. At the heart of the OODA system is its world model - a distributed data store built to quickly query big data quantities of information spread out across multiple processing nodes and data centers. The world model applies a multi-index approach where each index is a distinct view on the data. This allows for analysts and analytics (algorithms) to access information through queries with a variety of terms that may be of interest to them. Our indices include: a structured global-graph view of knowledge, a keyword search of data content, an object-characteristic range search, and a geospatial-temporal orientation of spatially located data. In addition, the world model applies a federated approach by connecting to existing databases and integrating them into one single interface as a "one-stop shopping place" to access SSA information. In addition to the world model, OODA provides a processing platform for various analysts to explore and analytics to execute upon this data. Analytic algorithms can use OODA to take raw data and build information from it. They can store these products back into the world model, allowing analysts to gain situational awareness with this information. Analysts in turn would help decision makers use this knowledge to address a wide range of SSA problems. OODA is designed to make it easy for software developers who build graphical user interfaces (GUIs) and algorithms to quickly get started with working with this data. This is done through a multi-language software development kit that includes multiple application program interfaces (APIs) and a data model with SSA concepts and terms such as: space observation, observable, measurable, metadata, track, space object, catalog, expectation, and maneuver.

Batch Model for Batched Timestamps Data Analysis with Application to the SSA Disability Program

PubMed Central

Yue, Qingqi; Yuan, Ao; Che, Xuan; Huynh, Minh; Zhou, Chunxiao

2016-01-01

The Office of Disability Adjudication and Review (ODAR) is responsible for holding hearings, issuing decisions, and reviewing appeals as part of the Social Security Administration’s disability determining process. In order to control and process cases, the ODAR has established a Case Processing and Management System (CPMS) to record management information since December 2003. The CPMS provides a detailed case status history for each case. Due to the large number of appeal requests and limited resources, the number of pending claims at ODAR was over one million cases by March 31, 2015. Our National Institutes of Health (NIH) team collaborated with SSA and developed a Case Status Change Model (CSCM) project to meet the ODAR’s urgent need of reducing backlogs and improve hearings and appeals process. One of the key issues in our CSCM project is to estimate the expected service time and its variation for each case status code. The challenge is that the systems recorded job departure times may not be the true job finished times. As the CPMS timestamps data of case status codes showed apparent batch patterns, we proposed a batch model and applied the constrained least squares method to estimate the mean service times and the variances. We also proposed a batch search algorithm to determine the optimal batch partition, as no batch partition was given in the real data. Simulation studies were conducted to evaluate the performance of the proposed methods. Finally, we applied the method to analyze a real CPMS data from ODAR/SSA. PMID:27747132

Microseismic Event Location Improvement Using Adaptive Filtering for Noise Attenuation

NASA Astrophysics Data System (ADS)

de Santana, F. L., Sr.; do Nascimento, A. F.; Leandro, W. P. D. N., Sr.; de Carvalho, B. M., Sr.

2017-12-01

In this work we show how adaptive filtering noise suppression improves the effectiveness of the Source Scanning Algorithm (SSA; Kao & Shan, 2004) in microseism location in the context of fracking operations. The SSA discretizes the time and region of interest in a 4D vector and, for each grid point and origin time, a brigthness value (seismogram stacking) is calculated. For a given set of velocity model parameters, when origin time and hypocenter of the seismic event are correct, a maximum value for coherence (or brightness) is achieved. The result is displayed on brightness maps for each origin time. Location methods such as SSA are most effective when the noise present in the seismograms is incoherent, however, the method may present false positives when the noise present in the data is coherent as occurs in fracking operations. To remove from the seismograms, the coherent noise from the pump and engines used in the operation, we use an adaptive filter. As the noise reference, we use the seismogram recorded at the station closest to the machinery employed. Our methodology was tested on semi-synthetic data. The microseismic was represented by Ricker pulses (with central frequency of 30Hz) on synthetics seismograms, and to simulate real seismograms on a surface microseismic monitoring situation, we added real noise recorded in a fracking operation to these synthetics seismograms. The results show that after the filtering of the seismograms, we were able to improve our detection threshold and to achieve a better resolution on the brightness maps of the located events.

Multiphoton minimal inertia scanning for fast acquisition of neural activity signals

NASA Astrophysics Data System (ADS)

Schuck, Renaud; Go, Mary Ann; Garasto, Stefania; Reynolds, Stephanie; Dragotti, Pier Luigi; Schultz, Simon R.

2018-04-01

Objective. Multi-photon laser scanning microscopy provides a powerful tool for monitoring the spatiotemporal dynamics of neural circuit activity. It is, however, intrinsically a point scanning technique. Standard raster scanning enables imaging at subcellular resolution; however, acquisition rates are limited by the size of the field of view to be scanned. Recently developed scanning strategies such as travelling salesman scanning (TSS) have been developed to maximize cellular sampling rate by scanning only select regions in the field of view corresponding to locations of interest such as somata. However, such strategies are not optimized for the mechanical properties of galvanometric scanners. We thus aimed to develop a new scanning algorithm which produces minimal inertia trajectories, and compare its performance with existing scanning algorithms. Approach. We describe here the adaptive spiral scanning (SSA) algorithm, which fits a set of near-circular trajectories to the cellular distribution to avoid inertial drifts of galvanometer position. We compare its performance to raster scanning and TSS in terms of cellular sampling frequency and signal-to-noise ratio (SNR). Main Results. Using surrogate neuron spatial position data, we show that SSA acquisition rates are an order of magnitude higher than those for raster scanning and generally exceed those achieved by TSS for neural densities comparable with those found in the cortex. We show that this result also holds true for in vitro hippocampal mouse brain slices bath loaded with the synthetic calcium dye Cal-520 AM. The ability of TSS to ‘park’ the laser on each neuron along the scanning trajectory, however, enables higher SNR than SSA when all targets are precisely scanned. Raster scanning has the highest SNR but at a substantial cost in number of cells scanned. To understand the impact of sampling rate and SNR on functional calcium imaging, we used the Cramér-Rao Bound on evoked calcium traces recorded simultaneously with electrophysiology traces to calculate the lower bound estimate of the spike timing occurrence. Significance. The results show that TSS and SSA achieve comparable accuracy in spike time estimates compared to raster scanning, despite lower SNR. SSA is an easily implementable way for standard multi-photon laser scanning systems to gain temporal precision in the detection of action potentials while scanning hundreds of active cells.

Selection of reference genes for microRNA analysis associated to early stress response to handling and confinement in Salmo salar.

PubMed

Zavala, Eduardo; Reyes, Daniela; Deerenberg, Robert; Vidal, Rodrigo

2017-05-11

MicroRNAs are key non-coding RNA molecules that play a relevant role in the regulation of gene expression through translational repression and/or transcript cleavage during normal development and physiological adaptation processes like stress. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) has become the approach normally used to determine the levels of microRNAs. However, this approach needs the use of endogenous reference. An improper selection of endogenous references can result in confusing interpretation of data. The aim of this study was to identify and validate appropriate endogenous reference miRNA genes for normalizing RT-qPCR survey of miRNAs expression in four different tissues of Atlantic salmon, under handling and confinement stress conditions associated to early or primary stress response. Nine candidate reference normalizers, including microRNAs and nuclear genes, normally used in vertebrate microRNA expression studies were selected from literature, validated by RT-qPCR and analyzed by the algorithms geNorm and NormFinder. The results revealed that the ssa-miR-99-5p gene was the most stable overall and that ssa-miR-99-5p and ssa-miR-23a-5p genes were the best combination. Moreover, the suitability of ssa-miR-99-5p and ssa-miR-23a-5p as endogeneuos reference genes was demostrated by the expression analysis of ssa-miR-193-5p gene.

High-Performance Computer Modeling of the Cosmos-Iridium Collision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olivier, S; Cook, K; Fasenfest, B

2009-08-28

This paper describes the application of a new, integrated modeling and simulation framework, encompassing the space situational awareness (SSA) enterprise, to the recent Cosmos-Iridium collision. This framework is based on a flexible, scalable architecture to enable efficient simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel, high-performance computer systems available, for example, at Lawrence Livermore National Laboratory. We will describe the application of this framework to the recent collision of the Cosmos and Iridium satellites, including (1) detailed hydrodynamic modeling of the satellitemore » collision and resulting debris generation, (2) orbital propagation of the simulated debris and analysis of the increased risk to other satellites (3) calculation of the radar and optical signatures of the simulated debris and modeling of debris detection with space surveillance radar and optical systems (4) determination of simulated debris orbits from modeled space surveillance observations and analysis of the resulting orbital accuracy, (5) comparison of these modeling and simulation results with Space Surveillance Network observations. We will also discuss the use of this integrated modeling and simulation framework to analyze the risks and consequences of future satellite collisions and to assess strategies for mitigating or avoiding future incidents, including the addition of new sensor systems, used in conjunction with the Space Surveillance Network, for improving space situational awareness.« less

Scale refinement and initial evaluation of a behavioral health function measurement tool for work disability evaluation.

PubMed

Marfeo, Elizabeth E; Ni, Pengsheng; Haley, Stephen M; Bogusz, Kara; Meterko, Mark; McDonough, Christine M; Chan, Leighton; Rasch, Elizabeth K; Brandt, Diane E; Jette, Alan M

2013-09-01

To use item response theory (IRT) data simulations to construct and perform initial psychometric testing of a newly developed instrument, the Social Security Administration Behavioral Health Function (SSA-BH) instrument, that aims to assess behavioral health functioning relevant to the context of work. Cross-sectional survey followed by IRT calibration data simulations. Community. Sample of individuals applying for Social Security Administration disability benefits: claimants (n=1015) and a normative comparative sample of U.S. adults (n=1000). None. SSA-BH measurement instrument. IRT analyses supported the unidimensionality of 4 SSA-BH scales: mood and emotions (35 items), self-efficacy (23 items), social interactions (6 items), and behavioral control (15 items). All SSA-BH scales demonstrated strong psychometric properties including reliability, accuracy, and breadth of coverage. High correlations of the simulated 5- or 10-item computer adaptive tests with the full item bank indicated robust ability of the computer adaptive testing approach to comprehensively characterize behavioral health function along 4 distinct dimensions. Initial testing and evaluation of the SSA-BH instrument demonstrated good accuracy, reliability, and content coverage along all 4 scales. Behavioral function profiles of Social Security Administration claimants were generated and compared with age- and sex-matched norms along 4 scales: mood and emotions, behavioral control, social interactions, and self-efficacy. Using the computer adaptive test-based approach offers the ability to collect standardized, comprehensive functional information about claimants in an efficient way, which may prove useful in the context of the Social Security Administration's work disability programs. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Comparison of Commonly-Used Microwave Radiative Transfer Models for Snow Remote Sensing

NASA Technical Reports Server (NTRS)

Royer, Alain; Roy, Alexandre; Montpetit, Benoit; Saint-Jean-Rondeau, Olivier; Picard, Ghislain; Brucker, Ludovic; Langlois, Alexandre

2017-01-01

This paper reviews four commonly-used microwave radiative transfer models that take different electromagnetic approaches to simulate snow brightness temperature (T(sub B)): the Dense Media Radiative Transfer - Multi-Layer model (DMRT-ML), the Dense Media Radiative Transfer - Quasi-Crystalline Approximation Mie scattering of Sticky spheres (DMRT-QMS), the Helsinki University of Technology n-Layers model (HUT-nlayers) and the Microwave Emission Model of Layered Snowpacks (MEMLS). Using the same extensively measured physical snowpack properties, we compared the simulated T(sub B) at 11, 19 and 37 GHz from these four models. The analysis focuses on the impact of using different types of measured snow microstructure metrics in the simulations. In addition to density, snow microstructure is defined for each snow layer by grain optical diameter (Do) and stickiness for DMRT-ML and DMRT-QMS, mean grain geometrical maximum extent (D(sub max)) for HUT n-layers and the exponential correlation length for MEMLS. These metrics were derived from either in-situ measurements of snow specific surface area (SSA) or macrophotos of grain sizes (D(sub max)), assuming non-sticky spheres for the DMRT models. Simulated T(sub B) sensitivity analysis using the same inputs shows relatively consistent T(sub B) behavior as a function of Do and density variations for the vertical polarization (maximum deviation of 18 K and 27 K, respectively), while some divergences appear in simulated variations for the polarization ratio (PR). Comparisons with ground based radiometric measurements show that the simulations based on snow SSA measurements have to be scaled with a model-specific factor of Do in order to minimize the root mean square error (RMSE) between measured and simulated T(sub B). Results using in-situ grain size measurements (SSA or D(sub max), depending on the model) give a mean T(sub B) RMSE (19 and 37 GHz) of the order of 16-26 K, which is similar for all models when the snow microstructure metrics are scaled. However, the MEMLS model converges to better results when driven by the correlation length estimated from in-situ SSA measurements rather than D(sub max) measurements. On a practical level, this paper shows that the SSA parameter, a snow property that is easy to retrieve in-situ, appears to be the most relevant parameter for characterizing snow microstructure, despite the need for a scaling factor.

The side-to-side fashion for individual distal coronary anastomosis using venous conduit.

PubMed

Kato, Takayoshi; Tsunekawa, Tomohiro; Motoji, Yusuke; Hirakawa, Akihiro; Okawa, Yasuhide; Tomita, Shinji

2017-04-01

Regarding to coronary artery bypass grafting (CABG), the end-to-side anastomosis (ESA) has been performed as a gold standard. Recently, the effectiveness of the distal side-to-side anastomosis (SSA) in CABG using internal mammary artery has been reported. The benefit of SSA comparing to ESA also has been disclosed by computing simulation. However, use of SSA by venous conduit for individual CABG has not been reported. In this study, we investigated feasibility of SSA. From January 2013 to October 2014, we conducted 114 CABGs. There were 92 venous distal anastomoses without sequential anastomotic site (61 SSA and 31 ESA). The anastomosis was evaluated before discharge and at 1 year after the procedure by angiography or multi-detector row computed tomographic coronary angiography. The median values for time to anastomosis were 13 min in the two group (p = 0.89). There was no revision of anastomosis in both groups. Additional stitches for hemostasis were required significantly less in SSA than ESA (18.0 vs 45.2 %, respectively, p < 0.05). Early angiographic patency; 96.6 % for SSA vs 93.5 % for ESA (p = 0.50), and percentage of good anastomotic figure; 91.2 % for SSA vs 87.1 % for ESA (p = 0.54) were similar in both groups. The angiographic patency at 1 year were 92.9 % for SSA and 81.0 % for ESA (p = 0.16). There was no predictive factor for early and late graft failure. Our study showed feasibility of SSA using venous conduit in individual CABG based on early and mid-term angiographic results. This anastomotic fashion is easy to perform and maybe beneficial in blood flow pattern.

Absorption Properties of Mediterranean Aerosols Obtained from Multi-year Ground-based and Satellite Remote Sensing Observations

NASA Technical Reports Server (NTRS)

Mallet, M.; Dubovik, O.; Nabat, P.; Dulac, F.; Kahn, R.; Sciare, J.; Paronis, D.; Leon, J. F.

2013-01-01

Aerosol absorption properties are of high importance to assess aerosol impact on regional climate. This study presents an analysis of aerosol absorption products obtained over the Mediterranean Basin or land stations in the region from multi-year ground-based AERONET and satellite observations with a focus on the Absorbing Aerosol Optical Depth (AAOD), Single Scattering Albedo (SSA) and their spectral dependence. The AAOD and Absorption Angstrom Exponent (AAE) data set is composed of daily averaged AERONET level 2 data from a total of 22 Mediterranean stations having long time series, mainly under the influence of urban-industrial aerosols and/or soil dust. This data set covers the 17 yr period 1996-2012 with most data being from 2003-2011 (approximately 89 percent of level-2 AAOD data). Since AERONET level-2 absorption products require a high aerosol load (AOD at 440 nm greater than 0.4), which is most often related to the presence of desert dust, we also consider level-1.5 SSA data, despite their higher uncertainty, and filter out data with an Angstrom exponent less than 1.0 in order to study absorption by carbonaceous aerosols. The SSA data set includes both AERONET level-2 and satellite level-3 products. Satellite-derived SSA data considered are monthly level 3 products mapped at the regional scale for the spring and summer seasons that exhibit the largest aerosol loads. The satellite SSA dataset includes the following products: (i) Multi-angle Imaging SpectroRadiometer (MISR) over 2000-2011, (ii) Ozone Monitoring Instrument (OMI) near-UV algorithm over 2004-2010, and (iii) MODerate resolution Imaging Spectroradiometer (MODIS) Deep-Blue algorithm over 2005-2011, derived only over land in dusty conditions. Sun-photometer observations show that values of AAOD at 440 nm vary between 0.024 +/- 0.01 (resp. 0.040 +/- 0.01) and 0.050 +/- 0.01 (0.055 +/- 0.01) for urban (dusty) sites. Analysis shows that the Mediterranean urban-industrial aerosols appear "moderately" absorbing with values of SSA close to approximately 0.94-0.95 +/- 0.04 (at 440 nm) in most cases except over the large cities of Rome and Athens, where aerosol appears more absorbing (SSA approximately 0.89-0.90 +/- 0.04). The aerosol Absorption Angstrom Exponent (AAE, estimated using 440 and 870 nm) is found to be larger than 1 for most sites over the Mediterranean, a manifestation of mineral dust (iron) and/or brown carbon producing the observed absorption. AERONET level-2 sun-photometer data indicate the existence of a moderate East-West gradient, with higher values over the eastern basin (AAEEast. = 1.39/AAEWest. = 1.33) due to the influence of desert dust. The North-South AAE gradient is more pronounced, especially over the western basin. Our additional analysis of AERONET level-1.5 data also shows that organic absorbing aerosols significantly affect some Mediterranean sites. These results indicate that current climate models treating organics as nonabsorbing over the Mediterranean certainly underestimate the warming effect due to carbonaceous aerosols. Acomparative analysis of the regional SSA variability has been attempted using satellite data. OMI and MODIS data show an absorbing zone (SSA approximately 0.90 at 470-500 nm) over Northeastern Africa that does not appear in the MISR retrievals. In contrast, MISR seems able to observe the East-West SSA gradient during summer, as also detected by AERONET. Also, the analysis of SSA provided by satellites indicates that the aerosol over the Mediterranean Sea appears less absorbing during spring (MAM) than summer (JJA).

Singular Spectrum Analysis for Astronomical Time Series: Constructing a Parsimonious Hypothesis Test

NASA Astrophysics Data System (ADS)

Greco, G.; Kondrashov, D.; Kobayashi, S.; Ghil, M.; Branchesi, M.; Guidorzi, C.; Stratta, G.; Ciszak, M.; Marino, F.; Ortolan, A.

We present a data-adaptive spectral method - Monte Carlo Singular Spectrum Analysis (MC-SSA) - and its modification to tackle astrophysical problems. Through numerical simulations we show the ability of the MC-SSA in dealing with 1/f β power-law noise affected by photon counting statistics. Such noise process is simulated by a first-order autoregressive, AR(1) process corrupted by intrinsic Poisson noise. In doing so, we statistically estimate a basic stochastic variation of the source and the corresponding fluctuations due to the quantum nature of light. In addition, MC-SSA test retains its effectiveness even when a significant percentage of the signal falls below a certain level of detection, e.g., caused by the instrument sensitivity. The parsimonious approach presented here may be broadly applied, from the search for extrasolar planets to the extraction of low-intensity coherent phenomena probably hidden in high energy transients.

Treemap Visualizations for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Ianni, J.; Gorrell, Z.

Making sense of massive data sets is a problem for many military domains including space. With unwieldy big data sets used for space situational awareness (SSA), important trends and outliers may not be easy to spot especially not at-a-glance. One method being explored to visualize SSA data sets is called treemapping. Treemaps fill screen space with nested rectangles (tiles) of various sizes and colors to represent multiple dimensions of hierarchical data sets. By mapping these dimensions effectively with a tiling algorithm that maintains an appropriate aspect ratio, patterns can emerge that often would have gone unnoticed. The ability to interactively perform range filtering (in our case with sliders) and object drill-downs (hyperlinking the tiles) make this technology powerful for in-depth analyses in addition to at-a-glance awareness. For one SSA analysis, the tiles could represent satellites that are grouped by country, sized by apogee, and colored/shaded by the launch date. Filter sliders could allow apogee range or launch dates to be narrowed for better resolution of a smaller data set. The application of this technology for the Joint Space Operations Center (JSpOC) Mission System (JMS) is being explored on a DARPA Small Business Innovative Research (SBIR) effort as a plug-in to the existing User-Defined Operational Picture (UDOP). In addition, visualization of DARPA OrbitOutlook small telescope data will be demonstrated. This research will investigate what SSA analyses are best served by treemaps, the best tiling algorithms for these problems, and how the treemaps should be integrated into the existing JMS UDOP workflow. Finally, we introduce a variation of treemaps that help leaders allocate their time to tasks based on importance and urgency.

The single scattering properties of the aerosol particles as aggregated spheres

NASA Astrophysics Data System (ADS)

Wu, Y.; Gu, X.; Cheng, T.; Xie, D.; Yu, T.; Chen, H.; Guo, J.

2012-08-01

The light scattering and absorption properties of anthropogenic aerosol particles such as soot aggregates are complicated in the temporal and spatial distribution, which introduce uncertainty of radiative forcing on global climate change. In order to study the single scattering properties of anthorpogenic aerosol particles, the structures of these aerosols such as soot paticles and soot-containing mixtures with the sulfate or organic matter, are simulated using the parallel diffusion limited aggregation algorithm (DLA) based on the transmission electron microscope images (TEM). Then, the single scattering properties of randomly oriented aerosols, such as scattering matrix, single scattering albedo (SSA), and asymmetry parameter (AP), are computed using the superposition T-matrix method. The comparisons of the single scattering properties of these specific types of clusters with different morphological and chemical factors such as fractal parameters, aspect ratio, monomer radius, mixture mode and refractive index, indicate that these different impact factors can respectively generate the significant influences on the single scattering properties of these aerosols. The results show that aspect ratio of circumscribed shape has relatively small effect on single scattering properties, for both differences of SSA and AP are less than 0.1. However, mixture modes of soot clusters with larger sulfate particles have remarkably important effects on the scattering and absorption properties of aggregated spheres, and SSA of those soot-containing mixtures are increased in proportion to the ratio of larger weakly absorbing attachments. Therefore, these complex aerosols come from man made pollution cannot be neglected in the aerosol retrievals. The study of the single scattering properties on these kinds of aggregated spheres is important and helpful in remote sensing observations and atmospheric radiation balance computations.

A Hybrid Short-Term Traffic Flow Prediction Model Based on Singular Spectrum Analysis and Kernel Extreme Learning Machine.

PubMed

Shang, Qiang; Lin, Ciyun; Yang, Zhaosheng; Bing, Qichun; Zhou, Xiyang

2016-01-01

Short-term traffic flow prediction is one of the most important issues in the field of intelligent transport system (ITS). Because of the uncertainty and nonlinearity, short-term traffic flow prediction is a challenging task. In order to improve the accuracy of short-time traffic flow prediction, a hybrid model (SSA-KELM) is proposed based on singular spectrum analysis (SSA) and kernel extreme learning machine (KELM). SSA is used to filter out the noise of traffic flow time series. Then, the filtered traffic flow data is used to train KELM model, the optimal input form of the proposed model is determined by phase space reconstruction, and parameters of the model are optimized by gravitational search algorithm (GSA). Finally, case validation is carried out using the measured data of an expressway in Xiamen, China. And the SSA-KELM model is compared with several well-known prediction models, including support vector machine, extreme learning machine, and single KLEM model. The experimental results demonstrate that performance of the proposed model is superior to that of the comparison models. Apart from accuracy improvement, the proposed model is more robust.

A Hybrid Short-Term Traffic Flow Prediction Model Based on Singular Spectrum Analysis and Kernel Extreme Learning Machine

PubMed Central

Lin, Ciyun; Yang, Zhaosheng; Bing, Qichun; Zhou, Xiyang

2016-01-01

Short-term traffic flow prediction is one of the most important issues in the field of intelligent transport system (ITS). Because of the uncertainty and nonlinearity, short-term traffic flow prediction is a challenging task. In order to improve the accuracy of short-time traffic flow prediction, a hybrid model (SSA-KELM) is proposed based on singular spectrum analysis (SSA) and kernel extreme learning machine (KELM). SSA is used to filter out the noise of traffic flow time series. Then, the filtered traffic flow data is used to train KELM model, the optimal input form of the proposed model is determined by phase space reconstruction, and parameters of the model are optimized by gravitational search algorithm (GSA). Finally, case validation is carried out using the measured data of an expressway in Xiamen, China. And the SSA-KELM model is compared with several well-known prediction models, including support vector machine, extreme learning machine, and single KLEM model. The experimental results demonstrate that performance of the proposed model is superior to that of the comparison models. Apart from accuracy improvement, the proposed model is more robust. PMID:27551829

Recent Research applications at the Athens Neutron Monitor Station

NASA Astrophysics Data System (ADS)

Mavromichalaki, H.; Gerontidou, M.; Paschalis, P.; Papaioannou, A.; Paouris, E.; Papailiou, M.; Souvatzoglou, G.

2015-08-01

The ground based neutron monitor measurements play a key role in the field of space physics, solar-terrestrial relations, and space weather applications. The Athens cosmic ray group has developed several research applications such as an optimized automated Ground Level Enhancement Alert (GLE Alert Plus) and a web interface, providing data from multiple Neutron Monitor stations (Multi-Station tool). These services are actually available via the Space Weather Portal operated by the European Space Agency (http://swe.ssa.esa.int). In addition, two simulation tools, based on Geant4, have also been implemented. The first one is for the simulation of the cosmic ray showers in the atmosphere (DYASTIMA) and the second one is for the simulation of the 6NM-64 neutron monitor. The contribution of the simulation tools to the calculations of the radiation dose received by air crews and passengers within the Earth's atmosphere and to the neutron monitor study is presented as well. Furthermore, the accurate calculation of the barometric coefficient and the primary data processing by filtering algorithms, such as the well known Median Editor and the developed by the Athens group ANN Algorithm and Edge Editor which contribute to the provision of high quality neutron monitor data are also discussed. Finally, a Space Weather Forecasting Center which provides a three day geomagnetic activity report on a daily basis has been set up and has been operating for the last two years at the Athens Neutron Monitor Station.

Simulations of a Canadian snowpack brightness temperatures using SURFEX-Crocus for Snow Water Equivalent (SWE) retrievals

NASA Astrophysics Data System (ADS)

Larue, Fanny; Royer, Alain; De Sève, Danielle; Langlois, Alexandre; Roy, Alexandre; Saint-Jean-Rondeau, Olivier

2016-04-01

In Quebec, the water associated to snowmelt represents 30% of the annual electricity production so that the snow cover evaluation in real time is of primary interest. The key variable is snow water equivalent (SWE) which describes the evolution of a global seasonal snow cover. However, the sparse distribution of meteorological stations in northern Québec generates great uncertainty in the extrapolation of SWE. On the contrary, the spatial and temporal coverage of satellite data offer a source of information with a high potential when considered as an alternative to the poor spatial distribution of in-situ information. Thus, this project aims to improve the prediction of SWE by assimilation of satellite passive microwave brightness temperatures (Tb) observations, independently of any ground observations. The snowpack evolution is simulated by the French snow model SURFEX-Crocus, driven by the Canadian atmospheric model GEM with a spatial resolution of 10 km. The bias of the atmospheric model and the impact of initialization errors on the simulated SWE were quantified from our ground measurements. To assimilate satellite observations, the multi-layered snow model is first coupled with a radiative transfer model using the Dense Media Radiative transfer theory (the DMRT-ML model) to estimate the microwave snow emission of the simulated snowpack. In order to retrieve simulated Tb in frequencies of interest (i.e. sensitive to snow dielectric properties), the snow microstructure needs to be well parameterized. It was shown in previous studies that the specific surface area (SSA) of snow grains is a well-defined parameter to describe the size and the shape of snow grains and which allows reproducible field measurements. SURFEX-Crocus estimates a SSA for each simulated snow layer, however, the snow microstructure in DMRT-ML is defined per layer by monodisperse optical radius of grain (~ 1/SSA) and by the stickiness which is not known. It thus becomes necessary to introduce an empirical factor (noted φ) due to the simplification of the representation of snow as non-sticky spheres of ice in the model. In other words, the measured and simulated SSA has to be converted in an effective snow grain metric by optimizing this scaling factor to minimize the root-mean-square error between the measured and simulated brightness temperatures. The φ factor scaling the Crocus simulated SSA was estimated using ground-based radiometric measurements made during several field campaigns in the James Bay territory, Nunavik (in 2013 and 2015), and Churchill, Manitoba in 2010. This new parameterization, adapted to the Canadian arctic and subarctic snowpack, represents an essential step to optimize SWE maps in this remote region which have yet to be proven accurate.

An adaptive singular spectrum analysis method for extracting brain rhythms of electroencephalography

PubMed Central

Hu, Hai; Guo, Shengxin; Liu, Ran

2017-01-01

Artifacts removal and rhythms extraction from electroencephalography (EEG) signals are important for portable and wearable EEG recording devices. Incorporating a novel grouping rule, we proposed an adaptive singular spectrum analysis (SSA) method for artifacts removal and rhythms extraction. Based on the EEG signal amplitude, the grouping rule determines adaptively the first one or two SSA reconstructed components as artifacts and removes them. The remaining reconstructed components are then grouped based on their peak frequencies in the Fourier transform to extract the desired rhythms. The grouping rule thus enables SSA to be adaptive to EEG signals containing different levels of artifacts and rhythms. The simulated EEG data based on the Markov Process Amplitude (MPA) EEG model and the experimental EEG data in the eyes-open and eyes-closed states were used to verify the adaptive SSA method. Results showed a better performance in artifacts removal and rhythms extraction, compared with the wavelet decomposition (WDec) and another two recently reported SSA methods. Features of the extracted alpha rhythms using adaptive SSA were calculated to distinguish between the eyes-open and eyes-closed states. Results showed a higher accuracy (95.8%) than those of the WDec method (79.2%) and the infinite impulse response (IIR) filtering method (83.3%). PMID:28674650

Local receptive field constrained stacked sparse autoencoder for classification of hyperspectral images.

PubMed

Wan, Xiaoqing; Zhao, Chunhui

2017-06-01

As a competitive machine learning algorithm, the stacked sparse autoencoder (SSA) has achieved outstanding popularity in exploiting high-level features for classification of hyperspectral images (HSIs). In general, in the SSA architecture, the nodes between adjacent layers are fully connected and need to be iteratively fine-tuned during the pretraining stage; however, the nodes of previous layers further away may be less likely to have a dense correlation to the given node of subsequent layers. Therefore, to reduce the classification error and increase the learning rate, this paper proposes the general framework of locally connected SSA; that is, the biologically inspired local receptive field (LRF) constrained SSA architecture is employed to simultaneously characterize the local correlations of spectral features and extract high-level feature representations of hyperspectral data. In addition, the appropriate receptive field constraint is concurrently updated by measuring the spatial distances from the neighbor nodes to the corresponding node. Finally, the efficient random forest classifier is cascaded to the last hidden layer of the SSA architecture as a benchmark classifier. Experimental results on two real HSI datasets demonstrate that the proposed hierarchical LRF constrained stacked sparse autoencoder and random forest (SSARF) provides encouraging results with respect to other contrastive methods, for instance, the improvements of overall accuracy in a range of 0.72%-10.87% for the Indian Pines dataset and 0.74%-7.90% for the Kennedy Space Center dataset; moreover, it generates lower running time compared with the result provided by similar SSARF based methodology.

Effect of black carbon on dust property retrievals from satellite observations

NASA Astrophysics Data System (ADS)

Lin, Tang-Huang; Yang, Ping; Yi, Bingqi

2013-01-01

The effect of black carbon on the optical properties of polluted mineral dust is studied from a satellite remote-sensing perspective. By including the auxiliary data of surface reflectivity and aerosol mixing weight, the optical properties of mineral dust, or more specifically, the aerosol optical depth (AOD) and single-scattering albedo (SSA), can be retrieved with improved accuracy. Precomputed look-up tables based on the principle of the Deep Blue algorithm are utilized in the retrieval. The mean differences between the retrieved results and the corresponding ground-based measurements are smaller than 1% for both AOD and SSA in the case of pure dust. However, the retrievals can be underestimated by as much as 11.9% for AOD and overestimated by up to 4.1% for SSA in the case of polluted dust with an estimated 10% (in terms of the number-density mixing ratio) of soot aggregates if the black carbon effect on dust aerosols is neglected.

Old Dog New Tricks: Use of Point-based Crop Models in Grid-based Regional Assessment of Crop Management Technologies Impact on Future Food Security

NASA Astrophysics Data System (ADS)

Koo, J.; Wood, S.; Cenacchi, N.; Fisher, M.; Cox, C.

2012-12-01

HarvestChoice (harvestchoice.org) generates knowledge products to guide strategic investments to improve the productivity and profitability of smallholder farming systems in sub-Saharan Africa (SSA). A keynote component of the HarvestChoice analytical framework is a grid-based overlay of SSA - a cropping simulation platform powered by process-based, crop models. Calibrated around the best available representation of cropping production systems in SSA, the simulation platform engages the DSSAT Crop Systems Model with the CENTURY Soil Organic Matter model (DSSAT-CENTURY) and provides a virtual experimentation module with which to explore the impact of a range of technological, managerial and environmental metrics on future crop productivity and profitability, as well as input use. For each of 5 (or 30) arc-minute grid cells in SSA, a stack of model input underlies it: datasets that cover soil properties and fertility, historic and future climate scenarios and farmers' management practices; all compiled from analyses of existing global and regional databases and consultations with other CGIAR centers. Running a simulation model is not always straightforward, especially when certain cropping systems or management practices are not even practiced by resource-poor farmers yet (e.g., precision agriculture) or they were never included in the existing simulation framework (e.g., water harvesting). In such cases, we used DSSAT-CENTURY as a function to iteratively estimate relative responses of cropping systems to technology-driven changes in water and nutrient balances compared to zero-adoption by farmers, while adjusting model input parameters to best mimic farmers' implementation of technologies in the field. We then fed the results of the simulation into to the economic and food trade model framework, IMPACT, to assess the potential implications on future food security. The outputs of the overall simulation analyses are packaged as a web-accessible database and published on the web with an interface that allows users to explore the simulation results in each country with user-defined baseline and what-if scenarios. The results are dynamically presented on maps, charts, and tables. This paper discusses the development of the simulation platform and its underlying data layers, a case study that assessed the role of potential crop management technology development, and the development of a web-based application that visualizes the simulation results.

Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

NASA Astrophysics Data System (ADS)

Gantt, B.; Kelly, J. T.; Bash, J. O.

2015-11-01

Sea spray aerosols (SSAs) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. Model evaluations of SSA emissions have mainly focused on the global scale, but regional-scale evaluations are also important due to the localized impact of SSAs on atmospheric chemistry near the coast. In this study, SSA emissions in the Community Multiscale Air Quality (CMAQ) model were updated to enhance the fine-mode size distribution, include sea surface temperature (SST) dependency, and reduce surf-enhanced emissions. Predictions from the updated CMAQ model and those of the previous release version, CMAQv5.0.2, were evaluated using several coastal and national observational data sets in the continental US. The updated emissions generally reduced model underestimates of sodium, chloride, and nitrate surface concentrations for coastal sites in the Bay Regional Atmospheric Chemistry Experiment (BRACE) near Tampa, Florida. Including SST dependency to the SSA emission parameterization led to increased sodium concentrations in the southeastern US and decreased concentrations along parts of the Pacific coast and northeastern US. The influence of sodium on the gas-particle partitioning of nitrate resulted in higher nitrate particle concentrations in many coastal urban areas due to increased condensation of nitric acid in the updated simulations, potentially affecting the predicted nitrogen deposition in sensitive ecosystems. Application of the updated SSA emissions to the California Research at the Nexus of Air Quality and Climate Change (CalNex) study period resulted in a modest improvement in the predicted surface concentration of sodium and nitrate at several central and southern California coastal sites. This update of SSA emissions enabled a more realistic simulation of the atmospheric chemistry in coastal environments where marine air mixes with urban pollution.

Multiscale implementation of infinite-swap replica exchange molecular dynamics.

PubMed

Yu, Tang-Qing; Lu, Jianfeng; Abrams, Cameron F; Vanden-Eijnden, Eric

2016-10-18

Replica exchange molecular dynamics (REMD) is a popular method to accelerate conformational sampling of complex molecular systems. The idea is to run several replicas of the system in parallel at different temperatures that are swapped periodically. These swaps are typically attempted every few MD steps and accepted or rejected according to a Metropolis-Hastings criterion. This guarantees that the joint distribution of the composite system of replicas is the normalized sum of the symmetrized product of the canonical distributions of these replicas at the different temperatures. Here we propose a different implementation of REMD in which (i) the swaps obey a continuous-time Markov jump process implemented via Gillespie's stochastic simulation algorithm (SSA), which also samples exactly the aforementioned joint distribution and has the advantage of being rejection free, and (ii) this REMD-SSA is combined with the heterogeneous multiscale method to accelerate the rate of the swaps and reach the so-called infinite-swap limit that is known to optimize sampling efficiency. The method is easy to implement and can be trivially parallelized. Here we illustrate its accuracy and efficiency on the examples of alanine dipeptide in vacuum and C-terminal β-hairpin of protein G in explicit solvent. In this latter example, our results indicate that the landscape of the protein is a triple funnel with two folded structures and one misfolded structure that are stabilized by H-bonds.

Using Machine Learning for Advanced Anomaly Detection and Classification

NASA Astrophysics Data System (ADS)

Lane, B.; Poole, M.; Camp, M.; Murray-Krezan, J.

2016-09-01

Machine Learning (ML) techniques have successfully been used in a wide variety of applications to automatically detect and potentially classify changes in activity, or a series of activities by utilizing large amounts data, sometimes even seemingly-unrelated data. The amount of data being collected, processed, and stored in the Space Situational Awareness (SSA) domain has grown at an exponential rate and is now better suited for ML. This paper describes development of advanced algorithms to deliver significant improvements in characterization of deep space objects and indication and warning (I&W) using a global network of telescopes that are collecting photometric data on a multitude of space-based objects. The Phase II Air Force Research Laboratory (AFRL) Small Business Innovative Research (SBIR) project Autonomous Characterization Algorithms for Change Detection and Characterization (ACDC), contracted to ExoAnalytic Solutions Inc. is providing the ability to detect and identify photometric signature changes due to potential space object changes (e.g. stability, tumble rate, aspect ratio), and correlate observed changes to potential behavioral changes using a variety of techniques, including supervised learning. Furthermore, these algorithms run in real-time on data being collected and processed by the ExoAnalytic Space Operations Center (EspOC), providing timely alerts and warnings while dynamically creating collection requirements to the EspOC for the algorithms that generate higher fidelity I&W. This paper will discuss the recently implemented ACDC algorithms, including the general design approach and results to date. The usage of supervised algorithms, such as Support Vector Machines, Neural Networks, k-Nearest Neighbors, etc., and unsupervised algorithms, for example k-means, Principle Component Analysis, Hierarchical Clustering, etc., and the implementations of these algorithms is explored. Results of applying these algorithms to EspOC data both in an off-line "pattern of life" analysis as well as using the algorithms on-line in real-time, meaning as data is collected, will be presented. Finally, future work in applying ML for SSA will be discussed.

Global Assessment of OMI Aerosol Single-scattering Albedo Using Ground-based AERONET and SKYNET Inversions

NASA Technical Reports Server (NTRS)

Jethva, Hiren; Torres, Omar; Ahn, Changwoo

2014-01-01

We compare the aerosol single-scattering albedo (SSA) retrieved by the near-UV two-channel algorithm (OMAERUV) applied to the Aura-Ozone Monitoring Instrument (OMI) measurements with an equivalent inversion made by the ground-based Aerosol Robotic Network (AERONET). This work is the first comprehensive effort to globally compare the OMI-retrieved SSA with that of AERONET using all available sites spanning the regions of biomass burning, dust, and urban pollution. An analysis of the co-located retrievals over 269 sites reveals that about 46 percent (69 percent) of OMI-AERONET matchups agree within the absolute difference of plus or minus 0.03 (plus or minus 0.05) for all aerosol types. The comparison improves to 52 percent (77 percent) when only 'smoke' and 'dust' aerosol types were identified by the OMAERUV algorithm. Regionally, the agreement between the two inversions was robust over the biomass burning sites of South America, Sahel, Indian subcontinent, and oceanic-coastal sites followed by a reasonable agreement over north-east Asia. Over the desert regions, OMI tends to retrieve higher SSA, particularly over the Arabian Peninsula. Globally, the OMI-AERONET matchups agree mostly within plus or minus 0.03 for the aerosol optical depth (440 nanometers) and UV-aerosol index larger than 0.4 and 1.0, respectively. We also compare the OMAERUV SSA against the inversion made by an independent network of ground-based radiometer called SKYNET with its operating sites in Japan, China, South-East Asia, India, and Europe. The advantage of the SKYNET database over AERONET is that it performs retrieval at near-UV wavelengths which facilitate the direct comparison of OMI retrievals with the equivalent ground-based inversion. Comparison of OMI and SKYNET over currently available sites reveals a good agreement between the two where more than 70 percent of matchups agree within the absolute difference of 0.05.

Aerosol Optical Properties Derived from the DRAGON-NE Asia Campaign, and Implications for a Single-Channel Algorithm to Retrieve Aerosol Optical Depth in Spring from Meteorological Imager (MI) On-Board the Communication, Ocean, and Meteorological Satellite (COMS)

NASA Technical Reports Server (NTRS)

Kim, M.; Kim, J.; Jeong, U.; Kim, W.; Hong, H.; Holben, B.; Eck, T. F.; Lim, J.; Song, C.; Lee, S.;

High Performance Computing Software Applications for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Giuliano, C.; Schumacher, P.; Matson, C.; Chun, F.; Duncan, B.; Borelli, K.; Desonia, R.; Gusciora, G.; Roe, K.

The High Performance Computing Software Applications Institute for Space Situational Awareness (HSAI-SSA) has completed its first full year of applications development. The emphasis of our work in this first year was in improving space surveillance sensor models and image enhancement software. These applications are the Space Surveillance Network Analysis Model (SSNAM), the Air Force Space Fence simulation (SimFence), and physically constrained iterative de-convolution (PCID) image enhancement software tool. Specifically, we have demonstrated order of magnitude speed-up in those codes running on the latest Cray XD-1 Linux supercomputer (Hoku) at the Maui High Performance Computing Center. The software applications improvements that HSAI-SSA has made, has had significant impact to the warfighter and has fundamentally changed the role of high performance computing in SSA.

Budgetary Impact of Telotristat Ethyl, a Novel Treatment for Patients with Carcinoid Syndrome Diarrhea: A US Health Plan Perspective.

PubMed

Joish, Vijay N; Frech, Feride; Lapuerta, Pablo

2017-12-01

Telotristat ethyl (TE) was recently approved for carcinoid syndrome diarrhea (CSD) in patients not adequately controlled with somatostatin analog long-acting release (SSA LAR) therapy alone. A budget impact model was developed to determine the short-term affordability of reimbursing TE in a US health plan. A budget impact model compared health care costs when CSD is managed per current treatment patterns (SSA LAR, reference drug scenario) versus when TE is incorporated in the treatment algorithm (SSA LAR + TE, new drug scenario). Prevalence of CSD, proportion of patients not adequately controlled on SSA LAR, monthly treatment costs (pharmacy and medical), and treatment efficacy were derived from the literature. In the reference drug scenario, an escalated monthly dose of SSA LAR therapy of 40 mg was assumed to treat patients with CSD not adequately controlled on the labeled dose of SSA LAR. In the new drug scenario, TE was added to the maximum labeled monthly dose of SSA LAR therapy of 30 mg. The incremental budget impact was calculated based on an assumed TE market uptake of 28%, 42%, and 55% during Years 1, 2, and 3, respectively. One-way sensitivity analyses were conducted to test model assumptions. A hypothetical health plan of 1 million members was estimated to have 42 prevalent CSD patients of whom 17 would be inadequately controlled on SSA LAR therapy. The monthly medical cost per patient not adequately controlled on SSA LAR in addition to pharmacotherapy was estimated to be $3946 based on the literature. Based on the observed treatment response in a clinical trial of 20% and 44% for the base case reference and new drug scenarios, total per patient per month costs were estimated to be $7563 and $11,205, respectively. Total annual costs in the new drug scenario were estimated to be $2.3 to $2.5 million during the first 3 years. The overall incremental annual costs were estimated to be $154,000 in Year 1, $231,000 in Year 2, and $302,000 in Year 3. This translated to an incremental per patient per month cost of $0.013, $0.019, and $0.025 for Years 1, 2, and 3. These results remained robust in 1-way sensitivity analyses. The availability of TE for patients not adequately controlled on SSA LAR therapy provides a novel treatment option for CSD. This model showed that providing access to this first-in-class oral agent would have a minimal budget impact to a US health plan. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Characterization and error analysis of an operational retrieval algorithm for estimating column ozone and aerosol properties from ground-based ultra-violet irradiance measurements

NASA Astrophysics Data System (ADS)

Taylor, Thomas E.; L'Ecuyer, Tristan; Slusser, James; Stephens, Graeme; Krotkov, Nick; Davis, John; Goering, Christian

2005-08-01

Extensive sensitivity and error characteristics of a recently developed optimal estimation retrieval algorithm which simultaneously determines aerosol optical depth (AOD), aerosol single scatter albedo (SSA) and total ozone column (TOC) from ultra-violet irradiances are described. The algorithm inverts measured diffuse and direct irradiances at 7 channels in the UV spectral range obtained from the United States Department of Agriculture's (USDA) UV-B Monitoring and Research Program's (UVMRP) network of 33 ground-based UV-MFRSR instruments to produce aerosol optical properties and TOC at all seven wavelengths. Sensitivity studies of the Tropospheric Ultra-violet/Visible (TUV) radiative transfer model performed for various operating modes (Delta-Eddington versus n-stream Discrete Ordinate) over domains of AOD, SSA, TOC, asymmetry parameter and surface albedo show that the solutions are well constrained. Realistic input error budgets and diagnostic and error outputs from the retrieval are analyzed to demonstrate the atmospheric conditions under which the retrieval provides useful and significant results. After optimizing the algorithm for the USDA site in Panther Junction, Texas the retrieval algorithm was run on a cloud screened set of irradiance measurements for the month of May 2003. Comparisons to independently derived AOD's are favorable with root mean square (RMS) differences of about 3% to 7% at 300nm and less than 1% at 368nm, on May 12 and 22, 2003. This retrieval method will be used to build an aerosol climatology and provide ground-truthing of satellite measurements by running it operationally on the USDA UV network database.

An Autonomous Sensor Tasking Approach for Large Scale Space Object Cataloging

NASA Astrophysics Data System (ADS)

Linares, R.; Furfaro, R.

The field of Space Situational Awareness (SSA) has progressed over the last few decades with new sensors coming online, the development of new approaches for making observations, and new algorithms for processing them. Although there has been success in the development of new approaches, a missing piece is the translation of SSA goals to sensors and resource allocation; otherwise known as the Sensor Management Problem (SMP). This work solves the SMP using an artificial intelligence approach called Deep Reinforcement Learning (DRL). Stable methods for training DRL approaches based on neural networks exist, but most of these approaches are not suitable for high dimensional systems. The Asynchronous Advantage Actor-Critic (A3C) method is a recently developed and effective approach for high dimensional systems, and this work leverages these results and applies this approach to decision making in SSA. The decision space for the SSA problems can be high dimensional, even for tasking of a single telescope. Since the number of SOs in space is relatively high, each sensor will have a large number of possible actions at a given time. Therefore, efficient DRL approaches are required when solving the SMP for SSA. This work develops a A3C based method for DRL applied to SSA sensor tasking. One of the key benefits of DRL approaches is the ability to handle high dimensional data. For example DRL methods have been applied to image processing for the autonomous car application. For example, a 256x256 RGB image has 196608 parameters (256*256*3=196608) which is very high dimensional, and deep learning approaches routinely take images like this as inputs. Therefore, when applied to the whole catalog the DRL approach offers the ability to solve this high dimensional problem. This work has the potential to, for the first time, solve the non-myopic sensor tasking problem for the whole SO catalog (over 22,000 objects) providing a truly revolutionary result.

DSCOVR EPIC AERUV Parameters

Atmospheric Science Data Center

2018-06-27

... AerosolType      The aerosol type associated with the ground pixel.        1 - Smoke ... algorithm flag associated with the ground pixel:     Aerosol extinction Optical Depth (AOD), Single Scattering Albedo (SSA), and     Aerosol Absorption Optical Depth (AAOD) Retrievals:        0 - Most ...

Dual Super-Systolic Core for Real-Time Reconstructive Algorithms of High-Resolution Radar/SAR Imaging Systems

PubMed Central

Atoche, Alejandro Castillo; Castillo, Javier Vázquez

2012-01-01

A high-speed dual super-systolic core for reconstructive signal processing (SP) operations consists of a double parallel systolic array (SA) machine in which each processing element of the array is also conceptualized as another SA in a bit-level fashion. In this study, we addressed the design of a high-speed dual super-systolic array (SSA) core for the enhancement/reconstruction of remote sensing (RS) imaging of radar/synthetic aperture radar (SAR) sensor systems. The selected reconstructive SP algorithms are efficiently transformed in their parallel representation and then, they are mapped into an efficient high performance embedded computing (HPEC) architecture in reconfigurable Xilinx field programmable gate array (FPGA) platforms. As an implementation test case, the proposed approach was aggregated in a HW/SW co-design scheme in order to solve the nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) from a remotely sensed scene. We show how such dual SSA core, drastically reduces the computational load of complex RS regularization techniques achieving the required real-time operational mode. PMID:22736964

MONALISA for stochastic simulations of Petri net models of biochemical systems.

PubMed

Balazki, Pavel; Lindauer, Klaus; Einloft, Jens; Ackermann, Jörg; Koch, Ina

2015-07-10

The concept of Petri nets (PN) is widely used in systems biology and allows modeling of complex biochemical systems like metabolic systems, signal transduction pathways, and gene expression networks. In particular, PN allows the topological analysis based on structural properties, which is important and useful when quantitative (kinetic) data are incomplete or unknown. Knowing the kinetic parameters, the simulation of time evolution of such models can help to study the dynamic behavior of the underlying system. If the number of involved entities (molecules) is low, a stochastic simulation should be preferred against the classical deterministic approach of solving ordinary differential equations. The Stochastic Simulation Algorithm (SSA) is a common method for such simulations. The combination of the qualitative and semi-quantitative PN modeling and stochastic analysis techniques provides a valuable approach in the field of systems biology. Here, we describe the implementation of stochastic analysis in a PN environment. We extended MONALISA - an open-source software for creation, visualization and analysis of PN - by several stochastic simulation methods. The simulation module offers four simulation modes, among them the stochastic mode with constant firing rates and Gillespie's algorithm as exact and approximate versions. The simulator is operated by a user-friendly graphical interface and accepts input data such as concentrations and reaction rate constants that are common parameters in the biological context. The key features of the simulation module are visualization of simulation, interactive plotting, export of results into a text file, mathematical expressions for describing simulation parameters, and up to 500 parallel simulations of the same parameter sets. To illustrate the method we discuss a model for insulin receptor recycling as case study. We present a software that combines the modeling power of Petri nets with stochastic simulation of dynamic processes in a user-friendly environment supported by an intuitive graphical interface. The program offers a valuable alternative to modeling, using ordinary differential equations, especially when simulating single-cell experiments with low molecule counts. The ability to use mathematical expressions provides an additional flexibility in describing the simulation parameters. The open-source distribution allows further extensions by third-party developers. The software is cross-platform and is licensed under the Artistic License 2.0.

Phase field crystal simulation of stress induced localized solid-state amorphization in nanocrystalline materials

NASA Astrophysics Data System (ADS)

Xi, Wen; Song, Xiaoqing; Hu, Shi; Chen, Zheng

2017-11-01

In this work, the phase field crystal (PFC) method is used to study the localized solid-state amorphization (SSA) and its dynamic transformation process in polycrystalline materials under the uniaxial tensile deformation with different factors. The impacts of these factors, including strain rates, temperatures and grain sizes, are analyzed. Kinetically, the ultra-high strain rate causes the lattice to be seriously distorted and the grain to gradually collapse, so the dislocation density rises remarkably. Therefore, localized SSA occurs. Thermodynamically, as high temperature increases the activation energy, the atoms are active and prefer to leave the original position, which induce atom rearrangement. Furthermore, small grain size increases the percentage of grain boundary and the interface free energy of the system. As a result, Helmholtz free energy increases. The dislocations and Helmholtz free energy act as the seed and driving force for the process of the localized SSA. Also, the critical diffusion-time step and the percentage of amorphous region areas are calculated. Through this work, the PFC method is proved to be an effective means to study localized SSA under uniaxial tensile deformation.

Phase field crystal simulation of stress induced localized solid-state amorphization in nanocrystalline materials.

PubMed

Xi, Wen; Song, Xiaoqing; Hu, Shi; Chen, Zheng

2017-11-29

In this work, the phase field crystal (PFC) method is used to study the localized solid-state amorphization (SSA) and its dynamic transformation process in polycrystalline materials under the uniaxial tensile deformation with different factors. The impacts of these factors, including strain rates, temperatures and grain sizes, are analyzed. Kinetically, the ultra-high strain rate causes the lattice to be seriously distorted and the grain to gradually collapse, so the dislocation density rises remarkably. Therefore, localized SSA occurs. Thermodynamically, as high temperature increases the activation energy, the atoms are active and prefer to leave the original position, which induce atom rearrangement. Furthermore, small grain size increases the percentage of grain boundary and the interface free energy of the system. As a result, Helmholtz free energy increases. The dislocations and Helmholtz free energy act as the seed and driving force for the process of the localized SSA. Also, the critical diffusion-time step and the percentage of amorphous region areas are calculated. Through this work, the PFC method is proved to be an effective means to study localized SSA under uniaxial tensile deformation.

Parallel STEPS: Large Scale Stochastic Spatial Reaction-Diffusion Simulation with High Performance Computers

PubMed Central

Chen, Weiliang; De Schutter, Erik

2017-01-01

Stochastic, spatial reaction-diffusion simulations have been widely used in systems biology and computational neuroscience. However, the increasing scale and complexity of models and morphologies have exceeded the capacity of any serial implementation. This led to the development of parallel solutions that benefit from the boost in performance of modern supercomputers. In this paper, we describe an MPI-based, parallel operator-splitting implementation for stochastic spatial reaction-diffusion simulations with irregular tetrahedral meshes. The performance of our implementation is first examined and analyzed with simulations of a simple model. We then demonstrate its application to real-world research by simulating the reaction-diffusion components of a published calcium burst model in both Purkinje neuron sub-branch and full dendrite morphologies. Simulation results indicate that our implementation is capable of achieving super-linear speedup for balanced loading simulations with reasonable molecule density and mesh quality. In the best scenario, a parallel simulation with 2,000 processes runs more than 3,600 times faster than its serial SSA counterpart, and achieves more than 20-fold speedup relative to parallel simulation with 100 processes. In a more realistic scenario with dynamic calcium influx and data recording, the parallel simulation with 1,000 processes and no load balancing is still 500 times faster than the conventional serial SSA simulation. PMID:28239346

Parallel STEPS: Large Scale Stochastic Spatial Reaction-Diffusion Simulation with High Performance Computers.

PubMed

Chen, Weiliang; De Schutter, Erik

2017-01-01

Stochastic, spatial reaction-diffusion simulations have been widely used in systems biology and computational neuroscience. However, the increasing scale and complexity of models and morphologies have exceeded the capacity of any serial implementation. This led to the development of parallel solutions that benefit from the boost in performance of modern supercomputers. In this paper, we describe an MPI-based, parallel operator-splitting implementation for stochastic spatial reaction-diffusion simulations with irregular tetrahedral meshes. The performance of our implementation is first examined and analyzed with simulations of a simple model. We then demonstrate its application to real-world research by simulating the reaction-diffusion components of a published calcium burst model in both Purkinje neuron sub-branch and full dendrite morphologies. Simulation results indicate that our implementation is capable of achieving super-linear speedup for balanced loading simulations with reasonable molecule density and mesh quality. In the best scenario, a parallel simulation with 2,000 processes runs more than 3,600 times faster than its serial SSA counterpart, and achieves more than 20-fold speedup relative to parallel simulation with 100 processes. In a more realistic scenario with dynamic calcium influx and data recording, the parallel simulation with 1,000 processes and no load balancing is still 500 times faster than the conventional serial SSA simulation.

Probability Forecasting Using Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Duncan, M.; Frisbee, J.; Wysack, J.

2014-09-01

Space Situational Awareness (SSA) is defined as the knowledge and characterization of all aspects of space. SSA is now a fundamental and critical component of space operations. Increased dependence on our space assets has in turn lead to a greater need for accurate, near real-time knowledge of all space activities. With the growth of the orbital debris population, satellite operators are performing collision avoidance maneuvers more frequently. Frequent maneuver execution expends fuel and reduces the operational lifetime of the spacecraft. Thus the need for new, more sophisticated collision threat characterization methods must be implemented. The collision probability metric is used operationally to quantify the collision risk. The collision probability is typically calculated days into the future, so that high risk and potential high risk conjunction events are identified early enough to develop an appropriate course of action. As the time horizon to the conjunction event is reduced, the collision probability changes. A significant change in the collision probability will change the satellite mission stakeholder's course of action. So constructing a method for estimating how the collision probability will evolve improves operations by providing satellite operators with a new piece of information, namely an estimate or 'forecast' of how the risk will change as time to the event is reduced. Collision probability forecasting is a predictive process where the future risk of a conjunction event is estimated. The method utilizes a Monte Carlo simulation that produces a likelihood distribution for a given collision threshold. Using known state and state uncertainty information, the simulation generates a set possible trajectories for a given space object pair. Each new trajectory produces a unique event geometry at the time of close approach. Given state uncertainty information for both objects, a collision probability value can be computed for every trail. This yields a collision probability distribution given known, predicted uncertainty. This paper presents the details of the collision probability forecasting method. We examine various conjunction event scenarios and numerically demonstrate the utility of this approach in typical event scenarios. We explore the utility of a probability-based track scenario simulation that models expected tracking data frequency as the tasking levels are increased. The resulting orbital uncertainty is subsequently used in the forecasting algorithm.

Joint Source Location and Focal Mechanism Inversion: efficiency, accuracy and applications

NASA Astrophysics Data System (ADS)

Liang, C.; Yu, Y.

2017-12-01

The analysis of induced seismicity has become a common practice to evaluate the results of hydraulic fracturing treatment. Liang et al (2016) proposed a joint Source Scanning Algorithms (jSSA for short) to obtain microseismic events and focal mechanisms simultaneously. The jSSA is superior over traditional SSA in many aspects, but the computation cost is too significant to be applied in real time monitoring. In this study, we have developed several scanning schemas to reduce computation time. A multi-stage scanning schema is proved to be able to improve the efficiency significantly while also retain its accuracy. A series of tests have been carried out by using both real field data and synthetic data to evaluate the accuracy of the method and its dependence on noise level, source depths, focal mechanisms and other factors. The surface-based arrays have better constraints on horizontal location errors (<20m) and angular errors of P axes (within 10 degree, for S/N>0.5). For sources with varying rakes, dips, strikes and depths, the errors are mostly controlled by the partition of positive and negative polarities in different quadrants. More evenly partitioned polarities in different quadrants yield better results in both locations and focal mechanisms. Nevertheless, even with bad resolutions for some FMs, the optimized jSSA method can still improve location accuracies significantly. Based on much more densely distributed events and focal mechanisms, a gridded stress inversion is conducted to get a evenly distributed stress field. The full potential of the jSSA has yet to be explored in different directions, especially in earthquake seismology as seismic array becoming incleasingly dense.

Sea spray aerosol as a unique source of ice nucleating particles

DOE PAGES

DeMott, Paul J.; Hill, Thomas C. J.; McCluskey, Christina S.; ...

2016-05-24

Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. In addition, data in the present study are also in accord with previously published INPmore » measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0°C, averaging an order of magnitude increase per 5°C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using “dry” geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. Lastly, these findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean.« less

Sea spray aerosol as a unique source of ice nucleating particles.

PubMed

DeMott, Paul J; Hill, Thomas C J; McCluskey, Christina S; Prather, Kimberly A; Collins, Douglas B; Sullivan, Ryan C; Ruppel, Matthew J; Mason, Ryan H; Irish, Victoria E; Lee, Taehyoung; Hwang, Chung Yeon; Rhee, Tae Siek; Snider, Jefferson R; McMeeking, Gavin R; Dhaniyala, Suresh; Lewis, Ernie R; Wentzell, Jeremy J B; Abbatt, Jonathan; Lee, Christopher; Sultana, Camille M; Ault, Andrew P; Axson, Jessica L; Diaz Martinez, Myrelis; Venero, Ingrid; Santos-Figueroa, Gilmarie; Stokes, M Dale; Deane, Grant B; Mayol-Bracero, Olga L; Grassian, Vicki H; Bertram, Timothy H; Bertram, Allan K; Moffett, Bruce F; Franc, Gary D

2016-05-24

Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. Data in the present study are also in accord with previously published INP measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0 °C, averaging an order of magnitude increase per 5 °C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using "dry" geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. These findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean.

Sea spray aerosol as a unique source of ice nucleating particles

PubMed Central

DeMott, Paul J.; Hill, Thomas C. J.; McCluskey, Christina S.; Prather, Kimberly A.; Ruppel, Matthew J.; Mason, Ryan H.; Irish, Victoria E.; Lee, Taehyoung; Hwang, Chung Yeon; Snider, Jefferson R.; McMeeking, Gavin R.; Dhaniyala, Suresh; Lewis, Ernie R.; Wentzell, Jeremy J. B.; Abbatt, Jonathan; Lee, Christopher; Sultana, Camille M.; Ault, Andrew P.; Axson, Jessica L.; Diaz Martinez, Myrelis; Venero, Ingrid; Santos-Figueroa, Gilmarie; Stokes, M. Dale; Deane, Grant B.; Mayol-Bracero, Olga L.; Grassian, Vicki H.; Bertram, Timothy H.; Bertram, Allan K.; Moffett, Bruce F.; Franc, Gary D.

2016-01-01

Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. Data in the present study are also in accord with previously published INP measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0 °C, averaging an order of magnitude increase per 5 °C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using “dry” geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. These findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean. PMID:26699469

Evaluation of Aerosol Optical Depth and Aerosol Models from VIIRS Retrieval Algorithms over North China Plain

NASA Technical Reports Server (NTRS)

Zhu, Jun; Xia, Xiangao; Wang, Jun; Che, Huizheng; Chen, Hongbin; Zhang, Jinqiang; Xu, Xiaoguang; Levy, Robert; Oo, Min; Holz, Robert;

Evaluation of aerosol optical depth and aerosol models from VIIRS retrieval algorithms over North China Plain.

PubMed

Zhu, Jun; Xia, Xiangao; Wang, Jun; Che, Huizheng; Chen, Hongbin; Zhang, Jinqiang; Xu, Xiaoguang; Levy, Robert; Oo, Min; Holz, Robert; Ayoub, Mohammed

2017-01-01

The first Visible Infrared Imaging Radiometer Suite (VIIRS) was launched on Suomi National Polar-orbiting Partnership (S-NPP) satellite in late 2011. Similar to the Moderate resolution Imaging Spectroradiometer (MODIS), VIIRS observes top-of-atmosphere spectral reflectance and is potentially suitable for retrieval of the aerosol optical depth (AOD). The VIIRS Environmental Data Record data (VIIRS_EDR) is produced operationally by NOAA, and is based on the MODIS atmospheric correction algorithm. The "MODIS-like" VIIRS data (VIIRS_ML) are being produced experimentally at NASA, from a version of the "dark-target" algorithm that is applied to MODIS. In this study, the AOD and aerosol model types from these two VIIRS retrieval algorithms over the North China Plain (NCP) are evaluated using the ground-based CE318 Sunphotometer (CE318) measurements during 2 May 2012 - 31 March 2014 at three sites. These sites represent three different surface types: urban (Beijing), suburban (XiangHe) and rural (Xinglong). Firstly, we evaluate the retrieved spectral AOD. For the three sites, VIIRS_EDR AOD at 550 nm shows a positive mean bias (MB) of 0.04-0.06 and the correlation of 0.83-0.86, with the largest MB (0.10-0.15) observed in Beijing. In contrast, VIIRS_ML AOD at 550 nm has overall higher positive MB of 0.13-0.14 and a higher correlation (0.93-0.94) with CE318 AOD. Secondly, we evaluate the aerosol model types assumed by each algorithm, as well as the aerosol optical properties used in the AOD retrievals. The aerosol model used in VIIRS_EDR algorithm shows that dust and clean urban models were the dominant model types during the evaluation period. The overall accuracy rate of the aerosol model used in VIIRS_ML over NCP three sites (0.48) is higher than that of VIIRS_EDR (0.27). The differences in Single Scattering Albedo (SSA) at 670 nm between VIIRS_ML and CE318 are mostly less than 0.015, but high seasonal differences are found especially over the Xinglong site. The values of SSA from VIIRS_EDR are higher than that observed by CE318 over all sites and all assumed aerosol modes, with a positive bias of 0.02-0.04 for fine mode, 0.06-0.12 for coarse mode and 0.03-0.05 for bi-mode at 440nm. The overestimation of SSA but positive AOD MB of VIIRS_EDR indicate that other factors (e.g. surface reflectance characterization or cloud contamination) are important sources of error in the VIIRS_EDR algorithm, and their effects on aerosol retrievals may override the effects from non-ideality in these aerosol models.

A trust-based sensor allocation algorithm in cooperative space search problems

NASA Astrophysics Data System (ADS)

Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik

2011-06-01

Sensor allocation is an important and challenging problem within the field of multi-agent systems. The sensor allocation problem involves deciding how to assign a number of targets or cells to a set of agents according to some allocation protocol. Generally, in order to make efficient allocations, we need to design mechanisms that consider both the task performers' costs for the service and the associated probability of success (POS). In our problem, the costs are the used sensor resource, and the POS is the target tracking performance. Usually, POS may be perceived differently by different agents because they typically have different standards or means of evaluating the performance of their counterparts (other sensors in the search and tracking problem). Given this, we turn to the notion of trust to capture such subjective perceptions. In our approach, we develop a trust model to construct a novel mechanism that motivates sensor agents to limit their greediness or selfishness. Then we model the sensor allocation optimization problem with trust-in-loop negotiation game and solve it using a sub-game perfect equilibrium. Numerical simulations are performed to demonstrate the trust-based sensor allocation algorithm in cooperative space situation awareness (SSA) search problems.

A New Undergraduate Course on the Physics of Space Situational Awareness

NASA Astrophysics Data System (ADS)

Jost, T.; Dearborn, M.; Chun, F.; McHarg, G.

As documented in the National Defense Authorization Act for fiscal year 2010, space situational awareness (SSA) is a high priority for the DoD and intelligence community. A fundamental understanding of the technical issues involved with SSA requires knowledge in many different scientific areas. The mission of the United States Air Force Academy (USAFA) is to educate, train, and inspire men and women to become officers of character motivated to lead the United States Air Force in service to our Nation. The physics department is implementing the USAFA mission and the need for technically competent officers in SSA through a comprehensive SSA Initiative. As part of the Initiative, we are developing a course to provide junior or senior cadets with the scientific background necessary to understand the challenges associated with SSA missions and systems. This presentation introduces the planned course objectives and includes a discussion of topics to be covered. Examples of topics include, optically resolved imaging, radiometry and photometry, radar detection and tracking, orbital prediction, debris and collision avoidance, detection of proximity operations and modeling and simulation tools. Cadets will have hands-on opportunities to collect metrics of a designated object using Academy assets such as the 41 cm telescope. Cadets will convert telescope gimbal angles into an orbital data. Cadets will synthesize what they learned in the course by completing the semester with a final project where the collected data is merged with a notional scenario to present a mock decision briefing. This class will be open to cadets of any academic major, since the intent is to prepare officers with basic technical competence in SSA applications. This is critical since graduates of the Academy become commissioned officers in the military and serve in a large variety of leadership positions -- from the researcher to the warfighter. Since we are currently developing the course, the SSA community will be invited to send online feedback to USAFA physics department faculty and to participate by providing materials that may be integrated into course.

Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution

PubMed Central

Hertz, Uri; Amedi, Amir

2015-01-01

The classical view of sensory processing involves independent processing in sensory cortices and multisensory integration in associative areas. This hierarchical structure has been challenged by evidence of multisensory responses in sensory areas, and dynamic weighting of sensory inputs in associative areas, thus far reported independently. Here, we used a visual-to-auditory sensory substitution algorithm (SSA) to manipulate the information conveyed by sensory inputs while keeping the stimuli intact. During scan sessions before and after SSA learning, subjects were presented with visual images and auditory soundscapes. The findings reveal 2 dynamic processes. First, crossmodal attenuation of sensory cortices changed direction after SSA learning from visual attenuations of the auditory cortex to auditory attenuations of the visual cortex. Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory. The interaction between these phenomena may play an important role in multisensory processing. Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus. These 2 factors allow for both stability and a fast, dynamic tuning of the system when required. PMID:24518756

Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution.

PubMed

Hertz, Uri; Amedi, Amir

2015-08-01

The classical view of sensory processing involves independent processing in sensory cortices and multisensory integration in associative areas. This hierarchical structure has been challenged by evidence of multisensory responses in sensory areas, and dynamic weighting of sensory inputs in associative areas, thus far reported independently. Here, we used a visual-to-auditory sensory substitution algorithm (SSA) to manipulate the information conveyed by sensory inputs while keeping the stimuli intact. During scan sessions before and after SSA learning, subjects were presented with visual images and auditory soundscapes. The findings reveal 2 dynamic processes. First, crossmodal attenuation of sensory cortices changed direction after SSA learning from visual attenuations of the auditory cortex to auditory attenuations of the visual cortex. Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory. The interaction between these phenomena may play an important role in multisensory processing. Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus. These 2 factors allow for both stability and a fast, dynamic tuning of the system when required. © The Author 2014. Published by Oxford University Press.

An orbital emulator for pursuit-evasion game theoretic sensor management

NASA Astrophysics Data System (ADS)

Shen, Dan; Wang, Tao; Wang, Gang; Jia, Bin; Wang, Zhonghai; Chen, Genshe; Blasch, Erik; Pham, Khanh

2017-05-01

This paper develops and evaluates an orbital emulator (OE) for space situational awareness (SSA). The OE can produce 3D satellite movements using capabilities generated from omni-wheeled robot and robotic arm motion methods. The 3D motion of a satellite is partitioned into the movements in the equatorial plane and the up-down motions in the vertical plane. The 3D actions are emulated by omni-wheeled robot models while the up-down motions are performed by a stepped-motor-controlled-ball along a rod (robotic arm), which is attached to the robot. For multiple satellites, a fast map-merging algorithm is integrated into the robot operating system (ROS) and simultaneous localization and mapping (SLAM) routines to locate the multiple robots in the scene. The OE is used to demonstrate a pursuit-evasion (PE) game theoretic sensor management algorithm, which models conflicts between a space-based-visible (SBV) satellite (as pursuer) and a geosynchronous (GEO) satellite (as evader). The cost function of the PE game is based on the informational entropy of the SBV-tracking-GEO scenario. GEO can maneuver using a continuous and low thruster. The hard-in-loop space emulator visually illustrates the SSA problem solution based PE game.

Unexpected series of regular frequency spacing of δ Scuti stars in the non-asymptotic regime. II. Sample-Echelle diagrams and rotation

DOE PAGES

Paparo, M.; Benko, J. M.; Hareter, M.; ...

2016-06-17

A sequence search method was developed for searching for regular frequency spacing in δ Scuti stars by visual inspection (VI) and algorithmic search. The sample contains 90 δ Scuti stars observed by CoRoT. An example is given to represent the VI. The algorithm (SSA) is described in detail. The data treatment of the CoRoT light curves, the criteria for frequency filtering, and the spacings derived by two methods (i.e., three approaches: VI, SSA, and FT) are given for each target. Echelle diagrams are presented for 77 targets for which at least one sequence of regular spacing was identified. Comparing the spacing and the shifts between pairs of echelle ridges revealed that at least one pair of echelle ridges is shifted to midway between the spacing for 22 stars. The estimated rotational frequencies compared to the shifts revealed rotationally split doublets, triplets, and multiplets not only for single frequencies, but for the complete echelle ridges in 31 δ Scuti stars. Furthermore, using several possible assumptions for the origin of the spacings, we derived the large separation (more » $${\\rm{\\Delta }}\

Unexpected series of regular frequency spacing of δ Scuti stars in the non-asymptotic regime. II. Sample-Echelle diagrams and rotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paparo, M.; Benko, J. M.; Hareter, M.

A sequence search method was developed for searching for regular frequency spacing in δ Scuti stars by visual inspection (VI) and algorithmic search. The sample contains 90 δ Scuti stars observed by CoRoT. An example is given to represent the VI. The algorithm (SSA) is described in detail. The data treatment of the CoRoT light curves, the criteria for frequency filtering, and the spacings derived by two methods (i.e., three approaches: VI, SSA, and FT) are given for each target. Echelle diagrams are presented for 77 targets for which at least one sequence of regular spacing was identified. Comparing the spacing and the shifts between pairs of echelle ridges revealed that at least one pair of echelle ridges is shifted to midway between the spacing for 22 stars. The estimated rotational frequencies compared to the shifts revealed rotationally split doublets, triplets, and multiplets not only for single frequencies, but for the complete echelle ridges in 31 δ Scuti stars. Furthermore, using several possible assumptions for the origin of the spacings, we derived the large separation (more » $${\\rm{\\Delta }}\

Delineation of Rupture Propagation of Large Earthquakes Using Source-Scanning Algorithm: A Control Study

NASA Astrophysics Data System (ADS)

Kao, H.; Shan, S.

2004-12-01

Determination of the rupture propagation of large earthquakes is important and of wide interest to the seismological research community. The conventional inversion method determines the distribution of slip at a grid of subfaults whose orientations are predefined. As a result, difference choices of fault geometry and dimensions often result in different solutions. In this study, we try to reconstruct the rupture history of an earthquake using the newly developed Source-Scanning Algorithm (SSA) without imposing any a priori constraints on the fault's orientation and dimension. The SSA identifies the distribution of seismic sources in two steps. First, it calculates the theoretical arrival times from all grid points inside the model space to all seismic stations by assuming an origin time. Then, the absolute amplitudes of the observed waveforms at the predicted arrival times are added to give the "brightness" of each time-space pair, and the brightest spots mark the locations of sources. The propagation of the rupture is depicted by the migration of the brightest spots throughout a prescribed time window. A series of experiments are conducted to test the resolution of the SSA inversion. Contrary to the conventional wisdom that seismometers should be placed as close as possible to the fault trace to give the best resolution in delineating rupture details, we found that the best results are obtained if the seismograms are recorded at a distance about half of the total rupture length away from the fault trace. This is especially true when the rupture duration is longer than ~10 s. A possible explanation is that the geometric spreading effects for waveforms from different segments of the rupture are about the same if the stations are sufficiently away from the fault trace, thus giving a uniform resolution to the entire rupture history.

The Sensitivity of SeaWiFS Ocean Color Retrievals to Aerosol Amount and Type

NASA Technical Reports Server (NTRS)

Kahn, Ralph A.; Sayer, Andrew M.; Ahmad, Ziauddin; Franz, Bryan A.

2016-01-01

As atmospheric reflectance dominates top-of-the-atmosphere radiance over ocean, atmospheric correction is a critical component of ocean color retrievals. This paper explores the operational Sea-viewing Wide Field-of-View Sensor (SeaWiFS) algorithm atmospheric correction with approximately 13 000 coincident surface-based aerosol measurements. Aerosol optical depth at 440 nm (AOD(sub 440)) is overestimated for AOD below approximately 0.1-0.15 and is increasingly underestimated at higher AOD; also, single-scattering albedo (SSA) appears overestimated when the actual value less than approximately 0.96.AOD(sub 440) and its spectral slope tend to be overestimated preferentially for coarse-mode particles. Sensitivity analysis shows that changes in these factors lead to systematic differences in derived ocean water-leaving reflectance (Rrs) at 440 nm. The standard SeaWiFS algorithm compensates for AOD anomalies in the presence of nonabsorbing, medium-size-dominated aerosols. However, at low AOD and with absorbing aerosols, in situ observations and previous case studies demonstrate that retrieved Rrs is sensitive to spectral AOD and possibly also SSA anomalies. Stratifying the dataset by aerosol-type proxies shows the dependence of the AOD anomaly and resulting Rrs patterns on aerosol type, though the correlation with the SSA anomaly is too subtle to be quantified with these data. Retrieved chlorophyll-a concentrations (Chl) are affected in a complex way by Rrs differences, and these effects occur preferentially at high and low Chl values. Absorbing aerosol effects are likely to be most important over biologically productive waters near coasts and along major aerosol transport pathways. These results suggest that future ocean color spacecraft missions aiming to cover the range of naturally occurring and anthropogenic aerosols, especially at wavelengths shorter than 440 nm, will require better aerosol amount and type constraints.

Joint Inversion of Source Location and Source Mechanism of Induced Microseismics

NASA Astrophysics Data System (ADS)

Liang, C.

2014-12-01

Seismic source mechanism is a useful property to indicate the source physics and stress and strain distribution in regional, local and micro scales. In this study we jointly invert source mechanisms and locations for microseismics induced in fluid fracturing treatment in the oil and gas industry. For the events that are big enough to see waveforms, there are quite a few techniques can be applied to invert the source mechanism including waveform inversion, first polarity inversion and many other methods and variants based on these methods. However, for events that are too small to identify in seismic traces such as the microseismics induced by the fluid fracturing in the Oil and Gas industry, a source scanning algorithms (SSA for short) with waveform stacking are usually applied. At the same time, a joint inversion of location and source mechanism are possible but at a cost of high computation budget. The algorithm is thereby called Source Location and Mechanism Scanning Algorithm, SLMSA for short. In this case, for given velocity structure, all possible combinations of source locations (X,Y and Z) and source mechanism (Strike, Dip and Rake) are used to compute travel-times and polarities of waveforms. Correcting Normal moveout times and polarities, and stacking all waveforms, the (X, Y, Z , strike, dip, rake) combination that gives the strongest stacking waveform is identified as the solution. To solve the problem of high computation problem, CPU-GPU programing is applied. Numerical datasets are used to test the algorithm. The SLMSA has also been applied to a fluid fracturing datasets and reveal several advantages against the location only method: (1) for shear sources, the source only program can hardly locate them because of the canceling out of positive and negative polarized traces, but the SLMSA method can successfully pick up those events; (2) microseismic locations alone may not be enough to indicate the directionality of micro-fractures. The statistics of source mechanisms can certainly provide more knowledges on the orientation of fractures; (3) in our practice, the joint inversion method almost always yield more events than the source only method and for those events that are also picked by the SSA method, the stacking power of SLMSA are always higher than the ones obtained in SSA.

An operational retrieval algorithm for determining aerosol optical properties in the ultraviolet

NASA Astrophysics Data System (ADS)

Taylor, Thomas E.; L'Ecuyer, Tristan S.; Slusser, James R.; Stephens, Graeme L.; Goering, Christian D.

2008-02-01

This paper describes a number of practical considerations concerning the optimization and operational implementation of an algorithm used to characterize the optical properties of aerosols across part of the ultraviolet (UV) spectrum. The algorithm estimates values of aerosol optical depth (AOD) and aerosol single scattering albedo (SSA) at seven wavelengths in the UV, as well as total column ozone (TOC) and wavelength-independent asymmetry factor (g) using direct and diffuse irradiances measured with a UV multifilter rotating shadowband radiometer (UV-MFRSR). A novel method for cloud screening the irradiance data set is introduced, as well as several improvements and optimizations to the retrieval scheme which yield a more realistic physical model for the inversion and increase the efficiency of the algorithm. Introduction of a wavelength-dependent retrieval error budget generated from rigorous forward model analysis as well as broadened covariances on the a priori values of AOD, SSA and g and tightened covariances of TOC allows sufficient retrieval sensitivity and resolution to obtain unique solutions of aerosol optical properties as demonstrated by synthetic retrievals. Analysis of a cloud screened data set (May 2003) from Panther Junction, Texas, demonstrates that the algorithm produces realistic values of the optical properties that compare favorably with pseudo-independent methods for AOD, TOC and calculated Ångstrom exponents. Retrieval errors of all parameters (except TOC) are shown to be negatively correlated to AOD, while the Shannon information content is positively correlated, indicating that retrieval skill improves with increasing atmospheric turbidity. When implemented operationally on more than thirty instruments in the Ultraviolet Monitoring and Research Program's (UVMRP) network, this retrieval algorithm will provide a comprehensive and internally consistent climatology of ground-based aerosol properties in the UV spectral range that can be used for both validation of satellite measurements as well as regional aerosol and ultraviolet transmission studies.

Electron Surfing Acceleration in High Mach Number Shocks

NASA Astrophysics Data System (ADS)

Hoshino, M.; Amano, T.; Matsumoto, Y.

2016-12-01

Many energetic events associated with shock waves have been argued in this context of the diffusive shock acceleration (DSA), and the origin of high-energy particles observed in astrophysical shocks are believed to be attributed to DSA. However, electron nonthermal acceleration still remains an unresolved issue of considerable interest. While cosmic rays of supernova remnant shocks with power-law spectra are believed to be produced by DSA, energetic electrons with a power-law energy spectrum are rarely ever observed at interplanetary shocks and at planetary bow shocks (e.g., Lario et al. 2003), and the diffusive-type acceleration seems to be necessarily malfunctioning in the heliosphere. The malfunctioning reason is thought to be a lack of pre-acceleration mechanism of supra-thermal electrons.In this presentation, we propose that the supra-thermal electrons can be generated by the mechanism of shock surfing acceleration (SSA) in a high Mach number magnetosonic shock. In the surfing mechanism, a series of large-amplitude electrostatic waves are excited by Buneman instability in the foot region under the interaction between the reflected ions and the incoming electrons, and it is argued that the electrons trapped in the electrostatic waves can be accelerated up to a relativistic energy (Hoshino and Shimada, 2002). Since the electron SSA has been studied based on one- or two-dimensional PIC simulations so far, SSA in three-dimensional system is questionable and remains an open question. We discuss based on our theoretical model and three-dimensional PIC simulation with a high-performance computing that the efficiency of SSA in three-dimensional system remains amazingly strong and plays an important role on the electron pre-acceleration/injection problem.

Ground Optical Signal Processing Architecture for Contributing SSA Space Based Sensor Data

NASA Astrophysics Data System (ADS)

Koblick, D.; Klug, M.; Goldsmith, A.; Flewelling, B.; Jah, M.; Shanks, J.; Piña, R.

2014-09-01

The main objective of the DARPA program Orbit Outlook (O^2) is to improve the metric tracking and detection performance of the Space Situational Network (SSN) by adding a diverse low-cost network of contributing sensors to the Space Situational Awareness (SSA) mission. In order to accomplish this objective, not only must a sensor be in constant communication with a planning and scheduling system to process tasking requests, there must be an underlying framework to provide useful data products, such as angles only measurements. Existing optical signal processing implementations such as the Optical Processing Architecture at Lincoln (OPAL) are capable of converting mission data collections to angles only observations, but may be difficult for many users to obtain, support, and customize for low-cost missions and demonstration programs. The Ground Optical Signal Processing Architecture (GOSPA) will ingest raw imagery and telemetry data from a space based electro optical sensor and perform a background removal process to remove anomalous pixels, interpolate over bad pixels, and dominant temporal noise. After background removal, the streak end points and target centroids are located using a corner detection algorithm developed by Air Force Research Laboratory. These identified streak locations are then fused with the corresponding spacecraft telemetry data to determine the Right Ascension and Declination measurements with respect to time. To demonstrate the performance of GOSPA, non-rate tracking collections against a satellite in Geosynchronous Orbit are simulated from a visible optical imaging sensor in a polar Low Earth Orbit. Stars, noise and bad pixels are added to the simulated images based on look angles and sensor parameters. These collections are run through the GOSPA framework to provide angles- only measurements to the Air Force Research Laboratory Constrained Admissible Region Multiple Hypothesis Filter (CAR-MHF) in which an Initial Orbit Determination is performed and compared to truth data.

Assessment of 10-Year Global Record of Aerosol Products from the OMI Near-UV Algorithm

NASA Astrophysics Data System (ADS)

Ahn, C.; Torres, O.; Jethva, H. T.

2014-12-01

Global observations of aerosol properties from space are critical for understanding climate change and air quality applications. The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on aerosol optical properties by making use of the large sensitivity to aerosol absorption and dark surface albedo in the UV spectral region. These unique features enable us to retrieve both aerosol extinction optical depth (AOD) and single scattering albedo (SSA) successfully from radiance measurements at 354 and 388 nm by the OMI near UV aerosol algorithm (OMAERUV). Recent improvements to algorithms in conjunction with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Atmospheric Infrared Sounder (AIRS) carbon monoxide data also reduce uncertainties due to aerosol layer heights and types significantly in retrieved products. We present validation results of OMI AOD against space and time collocated Aerosol Robotic Network (AERONET) measured AOD values over multiple stations representing major aerosol episodes and regimes. We also compare the OMI SSA against the inversion made by AERONET as well as an independent network of ground-based radiometer called SKYNET in Japan, China, South-East Asia, India, and Europe. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term aerosol record shows remarkable sensor stability. The OMAERUV 10-year global aerosol record is publicly available at the NASA data service center web site (http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omaeruv_v003.shtml).

Development of HWIL Testing Capabilities for Satellite Target Emulation at AEDC

NASA Astrophysics Data System (ADS)

Lowry, H.; Crider, D.; Burns, J.; Thompson, R.; Goldsmith, G., II; Sholes, W.

Programs involved in Space Situational Awareness (SSA) need the capability to test satellite sensors in a Hardware-in-the-Loop (HWIL) environment. Testing in a ground system avoids the significant cost of on-orbit test targets and the resulting issues such as debris mitigation, and in-space testing implications. The space sensor test facilities at AEDC consist of cryo-vacuum chambers that have been developed to project simulated targets to air-borne, space-borne, and ballistic platforms. The 7V chamber performs calibration and characterization of surveillance and seeker systems, as well as some mission simulation. The 10V chamber is being upgraded to provide real-time target simulation during the detection, acquisition, discrimination, and terminal phases of a seeker mission. The objective of the Satellite Emulation project is to upgrade this existing capability to support the ability to discern and track other satellites and orbital debris in a HWIL capability. It would provide a baseline for realistic testing of satellite surveillance sensors, which would be operated in a controlled environment. Many sensor functions could be tested, including scene recognition and maneuvering control software, using real interceptor hardware and software. Statistically significant and repeatable datasets produced by the satellite emulation system can be acquired during such test and saved for further analysis. In addition, the robustness of the discrimination and tracking algorithms can be investigated by a parametric analysis using slightly different scenarios; this will be used to determine critical points where a sensor system might fail. The radiometric characteristics of satellites are expected to be similar to the targets and decoys that make up a typical interceptor mission scenario, since they are near ambient temperature. Their spectral reflectivity, emissivity, and shape must also be considered, but the projection systems employed in the 7V and 10V chambers should be capable of providing the simulation of satellites as well. There may also be a need for greater radiometric intensity or shorter time response. An appropriate satellite model is integral to the scene generation process to meet the requirements of SSA programs. The Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) facility and the Guided Weapons Evaluation Facility (GWEF), both at Eglin Air Force Base, FL are assisting in developing the scene projection hardware, based on their significant test experience using resistive emitter arrays to test interceptors in a real-time environment. Army Aviation and Missile Research & Development Command (AMRDEC) will develop the Scene Generation System for the real-time mission simulation.

Evolution of the Standard Simulation Architecture

DTIC Science & Technology

2004-06-01

Interoperability Workshop, Paper 02S-SIW-016. 5. Deitel & Deitel , 2001. “C++ How to Program , Third Edition.” Prentice Hall, Inc., Upper Saddle...carefully followed for software to be successfully reused in other programs . The Standard Simulation Architecture (SSA) promotes these principles...capabilities described in this paper have been developed and successfully used on various government programs . This paper attempts to bring these

Proposed correlation of structure network inherited from producing techniques and deformation behavior for Ni-Ti-Mo metallic glasses via atomistic simulations

PubMed Central

Yang, M. H.; Li, J. H.; Liu, B. X.

2016-01-01

Based on the newly constructed n-body potential of Ni-Ti-Mo system, Molecular Dynamics and Monte Carlo simulations predict an energetically favored glass formation region and an optimal composition sub-region with the highest glass-forming ability. In order to compare the producing techniques between liquid melt quenching (LMQ) and solid-state amorphization (SSA), inherent hierarchical structure and its effect on mechanical property were clarified via atomistic simulations. It is revealed that both producing techniques exhibit no pronounced differences in the local atomic structure and mechanical behavior, while the LMQ method makes a relatively more ordered structure and a higher intrinsic strength. Meanwhile, it is found that the dominant short-order clusters of Ni-Ti-Mo metallic glasses obtained by LMQ and SSA are similar. By analyzing the structural evolution upon uniaxial tensile deformation, it is concluded that the gradual collapse of the spatial structure network is intimately correlated to the mechanical response of metallic glasses and acts as a structural signature of the initiation and propagation of shear bands. PMID:27418115

The requirements of yeast Hsp70 of SSA family for the ubiquitin-dependent degradation of short-lived and abnormal proteins.

PubMed

Lee, Do Hee; Sherman, Michael Y; Goldberg, Alfred L

2016-06-17

Cytoplasmic Hsp70s of SSA family, especially Ssa1p, are involved in the degradation of a variety of misfolded proteins in yeast. However the importance of other Ssa proteins in this process is unclear. To clarify the role(s) of individual Ssa proteins in proteolysis, we measured the breakdown of various cell proteins in mutants lacking different Ssa proteins. In mutants lacking Ssa1p and Ssa2p, the proteasomal degradation of short-lived proteins was reduced, which was not restored fully by the over-expression of Ssa1p. By contrast, the degradation of stable cellular proteins did not require Ssa proteins. The degradation of the cytosolic model substrates (Ub-P-β-gal and R-β-gal) and their ubiquitylation were inhibited by the inactivation of Ssa proteins. In addition, Ssa1p and the co-chaperone Ydj1p are indispensable for the intracellular degradation of a mutant secretory protein, Siiyama variant of human antitrypsin. Our findings indicate that both Ssa1p and Ssa2p are essential for the ubiquitin-dependent degradation of short-lived proteins and the requirements of Ssa proteins and the co-chaperones widely vary depending on the conformations and folding status of the substrates. Copyright © 2016 Elsevier Inc. All rights reserved.

Evolution of the Specific Surface Area of Snow in a High Temperature Gradient Metamorphism

NASA Astrophysics Data System (ADS)

Wang, X.; Baker, I.

2014-12-01

The structural evolution of low-density snow under a high temperature gradient over a short period usually takes place in the surface layers during diurnal recrystallization or on a clear, cold night. To relate snow microstructures with their thermal properties, we combined X-ray computed microtomography (micro-CT) observations with numerical simulations. Different types of snow were tested over a large range of TGs (100 K m-1- 500 K m-1). The Specific Surface Area (SSA) was used to characterize the temperature gradient metamorphism (TGM). The magnitude of the temperature gradient and the initial snow type both influence the evolution of SSA. The SSA evolution under TGM was dominated by grain growth and the formation of complex surfaces. Fresh snow experienced a logarithmic decrease of SSA with time, a feature been observed previously by others [Calonne et al., 2014; Schneebeli and Sokratov, 2004; Taillandier et al., 2007]. However, for initial rounded and connected snow structures, the SSA will increase during TGM. Understanding the SSA increase is important in order to predict the enhanced uptake of chemical species by snow or increase in snow albedo. Calonne, N., F. Flin, C. Geindreau, B. Lesaffre, and S. Rolland du Roscoat (2014), Study of a temperature gradient metamorphism of snow from 3-D images: time evolution of microstructures, physical properties and their associated anisotropy, The Cryosphere Discussions, 8, 1407-1451, doi:10.5194/tcd-8-1407-2014. Schneebeli, M., and S. A. Sokratov (2004), Tomography of temperature gradient metamorphism of snow and associated changes in heat conductivity, Hydrological Processes, 18(18), 3655-3665, doi:10.1002/hyp.5800. Taillandier, A. S., F. Domine, W. R. Simpson, M. Sturm, and T. A. Douglas (2007), Rate of decrease of the specific surface area of dry snow: Isothermal and temperature gradient conditions, Journal of Geophysical Research: Earth Surface (2003-2012), 112(F3), doi: 10.1029/2006JF000514.

GPU-based Space Situational Awareness Simulation utilising Parallelism for Enhanced Multi-sensor Management

NASA Astrophysics Data System (ADS)

Hobson, T.; Clarkson, V.

2012-09-01

As a result of continual space activity since the 1950s, there are now a large number of man-made Resident Space Objects (RSOs) orbiting the Earth. Because of the large number of items and their relative speeds, the possibility of destructive collisions involving important space assets is now of significant concern to users and operators of space-borne technologies. As a result, a growing number of international agencies are researching methods for improving techniques to maintain Space Situational Awareness (SSA). Computer simulation is a method commonly used by many countries to validate competing methodologies prior to full scale adoption. The use of supercomputing and/or reduced scale testing is often necessary to effectively simulate such a complex problem on todays computers. Recently the authors presented a simulation aimed at reducing the computational burden by selecting the minimum level of fidelity necessary for contrasting methodologies and by utilising multi-core CPU parallelism for increased computational efficiency. The resulting simulation runs on a single PC while maintaining the ability to effectively evaluate competing methodologies. Nonetheless, the ability to control the scale and expand upon the computational demands of the sensor management system is limited. In this paper, we examine the advantages of increasing the parallelism of the simulation by means of General Purpose computing on Graphics Processing Units (GPGPU). As many sub-processes pertaining to SSA management are independent, we demonstrate how parallelisation via GPGPU has the potential to significantly enhance not only research into techniques for maintaining SSA, but also to enhance the level of sophistication of existing space surveillance sensors and sensor management systems. Nonetheless, the use of GPGPU imposes certain limitations and adds to the implementation complexity, both of which require consideration to achieve an effective system. We discuss these challenges and how they can be overcome. We further describe an application of the parallelised system where visibility prediction is used to enhance sensor management. This facilitates significant improvement in maximum catalogue error when RSOs become temporarily unobservable. The objective is to demonstrate the enhanced scalability and increased computational capability of the system.

SUBSTRUCTURE WITHIN THE SSA22 PROTOCLUSTER AT z ≈ 3.09

DOE Office of Scientific and Technical Information (OSTI.GOV)

Topping, Michael W.; Shapley, Alice E.; Steidel, Charles C., E-mail: mtopping@astro.ucla.edu

We present the results of a densely sampled spectroscopic survey of the SSA22 protocluster at z ≈ 3.09. Our sample with Keck/LRIS spectroscopy includes 106 Ly α emitters (LAEs) and 40 Lyman break galaxies (LBGs) at z = 3.05–3.12. These galaxies are contained within the 9′ × 9′ region in which the protocluster was discovered, which also hosts the maximum galaxy overdensity in the SSA22 region. The redshift histogram of our spectroscopic sample reveals two distinct peaks, at z = 3.069 (blue; 43 galaxies) and z = 3.095 (red; 103 galaxies). Furthermore, objects in the blue and red peaks aremore » segregated on the sky, with galaxies in the blue peak concentrating toward the western half of the field. These results suggest that the blue and red redshift peaks represent two distinct structures in physical space. Although the double-peaked redshift histogram is traced in the same manner by LBGs and LAEs, and brighter and fainter galaxies, we find that 9 out of 10 X-ray AGNs in SSA22, and all 7 spectroscopically confirmed giant Ly α “blobs,” reside in the red peak. We combine our data set with sparsely sampled spectroscopy from the literature over a significantly wider area, finding preliminary evidence that the double-peaked structure in redshift space extends beyond the region of our dense spectroscopic sampling. In order to fully characterize the three-dimensional structure, dynamics, and evolution of large-scale structure in the SSA22 overdensity, we require the measurement of large samples of LAE and LBG redshifts over a significantly wider area, as well as detailed comparisons with cosmological simulations of massive cluster formation.« less

Relationship between individual neuron and network spontaneous activity in developing mouse cortex.

PubMed

Barnett, Heather M; Gjorgjieva, Julijana; Weir, Keiko; Comfort, Cara; Fairhall, Adrienne L; Moody, William J

2014-12-15

Spontaneous synchronous activity (SSA) that propagates as electrical waves is found in numerous central nervous system structures and is critical for normal development, but the mechanisms of generation of such activity are not clear. In previous work, we showed that the ventrolateral piriform cortex is uniquely able to initiate SSA in contrast to the dorsal neocortex, which participates in, but does not initiate, SSA (Lischalk JW, Easton CR, Moody WJ. Dev Neurobiol 69: 407-414, 2009). In this study, we used Ca(2+) imaging of cultured embryonic day 18 to postnatal day 2 coronal slices (embryonic day 17 + 1-4 days in culture) of the mouse cortex to investigate the different activity patterns of individual neurons in these regions. In the piriform cortex where SSA is initiated, a higher proportion of neurons was active asynchronously between waves, and a larger number of groups of coactive cells was present compared with the dorsal cortex. When we applied GABA and glutamate synaptic antagonists, asynchronous activity and cellular clusters remained, while synchronous activity was eliminated, indicating that asynchronous activity is a result of cell-intrinsic properties that differ between these regions. To test the hypothesis that higher levels of cell-autonomous activity in the piriform cortex underlie its ability to initiate waves, we constructed a conductance-based network model in which three layers differed only in the proportion of neurons able to intrinsically generate bursting behavior. Simulations using this model demonstrated that a gradient of intrinsic excitability was sufficient to produce directionally propagating waves that replicated key experimental features, indicating that the higher level of cell-intrinsic activity in the piriform cortex may provide a substrate for SSA generation. Copyright © 2014 the American Physiological Society.

20 CFR 422.705 - When SSA employees may listen-in to or record telephone conversations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false When SSA employees may listen-in to or record... ORGANIZATION AND PROCEDURES Use of SSA Telephone Lines § 422.705 When SSA employees may listen-in to or record telephone conversations. SSA employees may listen-in to or record telephone conversations on SSA telephone...

Self-regulation of 70-kilodalton heat shock proteins in Saccharomyces cerevisiae.

PubMed Central

Stone, D E; Craig, E A

1990-01-01

To determine whether the 70-kilodalton heat shock proteins of Saccharomyces cerevisiae play a role in regulating their own synthesis, we studied the effect of overexpressing the SSA1 protein on the activity of the SSA1 5'-regulatory region. The constitutive level of Ssa1p was increased by fusing the SSA1 structural gene to the GAL1 promoter. A reporter vector consisting of an SSA1-lacZ translational fusion was used to assess SSA1 promoter activity. In a strain producing approximately 10-fold the normal heat shock level of Ssa1p, induction of beta-galactosidase activity by heat shock was almost entirely blocked. Expression of a transcriptional fusion vector in which the CYC1 upstream activating sequence of a CYC1-lacZ chimera was replaced by a sequence containing a heat shock upstream activating sequence (heat shock element 2) from the 5'-regulatory region of SSA1 was inhibited by excess Ssa1p. The repression of an SSA1 upstream activating sequence by the SSA1 protein indicates that SSA1 self-regulation is at least partially mediated at the transcriptional level. The expression of another transcriptional fusion vector, containing heat shock element 2 and a lesser amount of flanking sequence, is not inhibited when Ssa1p is overexpressed. This suggests the existence of an element, proximal to or overlapping heat shock element 2, that confers sensitivity to the SSA1 protein. Images PMID:2181281

Constraining the long-term climate reponse to stratospheric sulfate aerosols injection by the short-term volcanic climate response

NASA Astrophysics Data System (ADS)

Plazzotta, M.; Seferian, R.; Douville, H.; Kravitz, B.; Tilmes, S.; Tjiputra, J.

2016-12-01

Rising greenhouse gas emissions are leading to global warming and climate change, which will have multiple impacts on human society. Geoengineering methods like solar radiation management by stratospheric sulfate aerosols injection (SSA-SRM) aim at treating the symptoms of climate change by reducing the global temperature. Since a real-world testing cannot be implemented, Earth System Models (ESMs) are useful tools to assess the climate impacts of such geoengineering methods. However, coordinated simulations performed with the Geoengineering Model Intercomparison Project (GeoMIP) have shown that climate cooling in response to a continuous injection of 5Tg of SO2 per year under RCP45 future projection (the so-called G4 experiment) differs substantially between ESMs. Here, we employ a volcano analog approach to constrain the climate response in SSA-SRM geoengineering simulations across an ensemble of 10 ESMs. We identify an emergent relationship between the long-term cooling in responses to the mitigation of the clear-sky surface downwelling shortwave radiation (RSDSCS), and the short-term cooling related to the change in RSDSCS during the major tropical volcanic eruptions observed over the historical period (1850-2005). This relationship explains almost 80% of the multi-model spread. Combined with contemporary observations of the latest volcanic eruptions (satellite observations and model reanalyzes), this relationship provides a tight constraint on the climate impacts of SSA-SRM. We estimate that a continuous injection of SO2 aerosols into the stratosphere will reduce the global average temperature of continental land surface by 0.47 K per W m-2, impacting both hydrological and carbon cycles. Compared with the unconstrained ESMs ensemble (range from 0.32 to 0.92 K per W m-2 ), our estimate represents much higher confidence ways to assess the impacts of SSA-SRM on the climate while ruling the most extreme projections of the unconstrained ensemble extremely unlikely.

Stochastic simulation of multiscale complex systems with PISKaS: A rule-based approach.

PubMed

Perez-Acle, Tomas; Fuenzalida, Ignacio; Martin, Alberto J M; Santibañez, Rodrigo; Avaria, Rodrigo; Bernardin, Alejandro; Bustos, Alvaro M; Garrido, Daniel; Dushoff, Jonathan; Liu, James H

2018-03-29

Computational simulation is a widely employed methodology to study the dynamic behavior of complex systems. Although common approaches are based either on ordinary differential equations or stochastic differential equations, these techniques make several assumptions which, when it comes to biological processes, could often lead to unrealistic models. Among others, model approaches based on differential equations entangle kinetics and causality, failing when complexity increases, separating knowledge from models, and assuming that the average behavior of the population encompasses any individual deviation. To overcome these limitations, simulations based on the Stochastic Simulation Algorithm (SSA) appear as a suitable approach to model complex biological systems. In this work, we review three different models executed in PISKaS: a rule-based framework to produce multiscale stochastic simulations of complex systems. These models span multiple time and spatial scales ranging from gene regulation up to Game Theory. In the first example, we describe a model of the core regulatory network of gene expression in Escherichia coli highlighting the continuous model improvement capacities of PISKaS. The second example describes a hypothetical outbreak of the Ebola virus occurring in a compartmentalized environment resembling cities and highways. Finally, in the last example, we illustrate a stochastic model for the prisoner's dilemma; a common approach from social sciences describing complex interactions involving trust within human populations. As whole, these models demonstrate the capabilities of PISKaS providing fertile scenarios where to explore the dynamics of complex systems. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

20 CFR 401.85 - Exempt systems.

Code of Federal Regulations, 2011 CFR

2011-04-01

... subsection (k)(2) of the Privacy Act: (A) The General Criminal Investigation Files, SSA; (B) The Criminal Investigations File, SSA; and, (C) The Program Integrity Case Files, SSA. (D) Civil and Administrative Investigative Files of the Inspector General, SSA/OIG. (E) Complaint Files and Log. SSA/OGC. (iii) Pursuant to...

The advanced receiver 2: Telemetry test results in CTA 21

NASA Technical Reports Server (NTRS)

Hinedi, S.; Bevan, R.; Marina, M.

1991-01-01

Telemetry tests with the Advanced Receiver II (ARX II) in Compatibility Test Area 21 are described. The ARX II was operated in parallel with a Block-III Receiver/baseband processor assembly combination (BLK-III/BPA) and a Block III Receiver/subcarrier demodulation assembly/symbol synchronization assembly combination (BLK-III/SDA/SSA). The telemetry simulator assembly provided the test signal for all three configurations, and the symbol signal to noise ratio as well as the symbol error rates were measured and compared. Furthermore, bit error rates were also measured by the system performance test computer for all three systems. Results indicate that the ARX-II telemetry performance is comparable and sometimes superior to the BLK-III/BPA and BLK-III/SDA/SSA combinations.

Using Single-Scattering Albedo Spectral Curvature to Characterize East Asian Aerosol Mixtures

NASA Technical Reports Server (NTRS)

Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

2015-01-01

Spectral dependence of aerosol single-scattering albedo (SSA) has been used to infer aerosol composition. In particular, aerosol mixtures dominated by dust absorption will have monotonically increasing SSA with wavelength while that dominated by black carbon absorption has monotonically decreasing SSA spectra. However, by analyzing SSA measured at four wavelengths, 440, 675, 870, and 1020 nm from the Aerosol Robotic Network data set, we find that the SSA spectra over East Asia are frequently peaked at 675 nm. In these cases, we suggest that SSA spectral curvature, defined as the negative of the second derivative of SSA as a function of wavelength, can provide additional information on the composition of these aerosol mixtures. Aerosol SSA spectral curvatures for East Asia during fall and winter are considerably larger than those found in places primarily dominated by biomass burning or dust aerosols. SSA curvature is found to increase as the SSA magnitude decreases. The curvature increases with coarse mode fraction (CMF) to a CMF value of about 0.4, then slightly decreases or remains constant at larger CMF. Mie calculations further verify that the strongest SSA curvature occurs at approx. 40% dust fraction, with 10% scattering aerosol fraction. The nonmonotonic SSA spectral dependence is likely associated with enhanced absorption in the shortwave by dust, absorption by black carbon at longer wavelengths, and also the flattened absorption optical depth spectral dependence due to the increased particle size.

Endoscopic analysis of colorectal serrated lesions with cancer.

PubMed

Nagata, Shuichiro; Mitsuyama, Keiichi; Kawano, Hiroshi; Noda, Tetsuhiro; Maeyama, Yasuhiko; Mukasa, Michita; Takedatsu, Hidetoshi; Yoshioka, Shinichiro; Kuwaki, Kotaro; Akiba, Jun; Tsuruta, Osamu; Torimura, Takuji

2018-06-01

Serrated lesions, including hyperplastic polyps (HPs), traditional serrated adenomas (TSAs) and sessile serrated adenomas/polyps (SSA/Ps), are important contributors to colorectal carcinogenesis. The aim of the present study was to analyze the potential of conventional endoscopy and advanced endoscopic imaging techniques to delineate the characteristic features of serrated lesions with cancer. The present study was a retrospective analysis of the data of 168 patients who had undergone colonoscopy, and a total of 228 serrated lesions (77 HPs, 58 TSAs, 84 SSA/Ps, 9 SSA/P plus TSAs) have been identified in these patients. A cancer component was identified in 2.6% of HPs, 13.8% of TSAs and 10.7% of SSA/Ps, but none of SSA/P plus TSAs. Compared with the lesions without cancer, the lesions with cancer exhibited a larger size (HP, TSA and SSA/P), a reddish appearance (SSA/P), a two-tier raised appearance (HP and SSA/P), a central depression (HP, TSA and SSA/P), the type V pit pattern (HP, TSA and SSA/P), and/or the type III capillary pattern (TSA and SSA/P). Deep invasion was identified in 50.0% of HPs, 12.5% of TSAs and 55.6% of SSA/Ps with cancer. The Ki-67 proliferative zone was distributed diffusely within the area of the cancer, but partially within the non-cancer area of HPs, TSAs and SSA/Ps. The lesion types were also analyzed on the basis of mucin phenotype. The present study suggested that a detailed endoscopic analysis of serrated lesions with cancer is useful for delineating characteristic features, and the analysis aids treatment selection.

Modeling the leaf angle dynamics in rice plant.

PubMed

Zhang, Yonghui; Tang, Liang; Liu, Xiaojun; Liu, Leilei; Cao, Weixing; Zhu, Yan

2017-01-01

The leaf angle between stem and sheath (SSA) is an important rice morphological trait. The objective of this study was to develop and validate a dynamic SSA model under different nitrogen (N) rates for selected rice cultivars. The time-course data of SSA were collected in three years, and a dynamic SSA model was developed for different main stem leaf ranks under different N rates for two selected rice cultivars. SSA increased with tiller age. The SSA of the same leaf rank increased with increase in N rate. The maximum SSA increased with leaf rank from the first to the third leaf, then decreased from the third to the final leaf. The relationship between the maximum SSA and leaf rank on main stem could be described with a linear piecewise function. The change of SSA with thermal time (TT) was described by a logistic equation. A variety parameter (the maximum SSA of the 3rd leaf on main stem) and a nitrogen factor were introduced to quantify the effect of cultivar and N rate on SSA. The model was validated against data collected from both pot and field experiments. The relative root mean square error (RRMSE) was 11.56% and 14.05%, respectively. The resulting models could be used for virtual rice plant modeling and plant-type design.

COMPARISON OF LAPAROSCOPIC SKILLS PERFORMANCE USING SINGLE-SITE ACCESS (SSA) DEVICES VS. AN INDEPENDENT-PORT SSA APPROACH

PubMed Central

Schill, Matthew R.; Varela, J. Esteban; Frisella, Margaret M.; Brunt, L. Michael

2015-01-01

Background We compared performance of validated laparoscopic tasks on four commercially available single site access (SSA) access devices (AD) versus an independent port (IP) SSA set-up. Methods A prospective, randomized comparison of laparoscopic skills performance on four AD (GelPOINT™, SILS™ Port, SSL Access System™, TriPort™) and one IP SSA set-up was conducted. Eighteen medical students (2nd–4th year), four surgical residents, and five attending surgeons were trained to proficiency in multi-port laparoscopy using four laparoscopic drills (peg transfer, bean drop, pattern cutting, extracorporeal suturing) in a laparoscopic trainer box. Drills were then performed in random order on each IP-SSA and AD-SSA set-up using straight laparoscopic instruments. Repetitions were timed and errors recorded. Data are mean ± SD, and statistical analysis was by two-way ANOVA with Tukey HSD post-hoc tests. Results Attending surgeons had significantly faster total task times than residents or students (p< 0.001), but the difference between residents and students was NS. Pair-wise comparisons revealed significantly faster total task times for the IP-SSA set-up compared to all four AD-SSA’s within the student group only (p<0.05). Total task times for residents and attending surgeons showed a similar profile, but the differences were NS. When data for the three groups was combined, the total task time was less for the IP-SSA set-up than for each of the four AD-SSA set-ups (p < 0.001). Similarly,, the IP-SSA set-up was significantly faster than 3 of 4 AD-SSA set-ups for peg transfer, 3 of 4 for pattern cutting, and 2 of 4 for suturing. No significant differences in error rates between IP-SSA and AD-SSA set-ups were detected. Conclusions When compared to an IP-SSA laparoscopic set-up, single site access devices are associated with longer task performance times in a trainer box model, independent of level of training. Task performance was similar across different SSA devices. PMID:21993938

Updating Sea Spray Aerosol Emissions in the Community Multiscale Air Quality Model

NASA Astrophysics Data System (ADS)

Gantt, B.; Bash, J. O.; Kelly, J.

2014-12-01

Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions, include sea surface temperature (SST) dependency, and revise surf zone emissions. Based on evaluation with several regional and national observational datasets in the continental U.S., the updated emissions generally improve surface concentrations predictions of primary aerosols composed of sea-salt and secondary aerosols affected by sea-salt chemistry in coastal and near-coastal sites. Specifically, the updated emissions lead to better predictions of the magnitude and coastal-to-inland gradient of sodium, chloride, and nitrate concentrations at Bay Regional Atmospheric Chemistry Experiment (BRACE) sites near Tampa, FL. Including SST-dependency to the SSA emission parameterization leads to increased sodium concentrations in the southeast U.S. and decreased concentrations along the Pacific coast and northeastern U.S., bringing predictions into closer agreement with observations at most Interagency Monitoring of Protected Visual Environments (IMPROVE) and Chemical Speciation Network (CSN) sites. Model comparison with California Research at the Nexus of Air Quality and Climate Change (CalNex) observations will also be discussed, with particular focus on the South Coast Air Basin where clean marine air mixes with anthropogenic pollution in a complex environment. These SSA emission updates enable more realistic simulation of chemical processes in coastal environments, both in clean marine air masses and mixtures of clean marine and polluted conditions.

Stimulus-specific adaptation in a recurrent network model of primary auditory cortex

PubMed Central

2017-01-01

Stimulus-specific adaptation (SSA) occurs when neurons decrease their responses to frequently-presented (standard) stimuli but not, or not as much, to other, rare (deviant) stimuli. SSA is present in all mammalian species in which it has been tested as well as in birds. SSA confers short-term memory to neuronal responses, and may lie upstream of the generation of mismatch negativity (MMN), an important human event-related potential. Previously published models of SSA mostly rely on synaptic depression of the feedforward, thalamocortical input. Here we study SSA in a recurrent neural network model of primary auditory cortex. When the recurrent, intracortical synapses display synaptic depression, the network generates population spikes (PSs). SSA occurs in this network when deviants elicit a PS but standards do not, and we demarcate the regions in parameter space that allow SSA. While SSA based on PSs does not require feedforward depression, we identify feedforward depression as a mechanism for expanding the range of parameters that support SSA. We provide predictions for experiments that could help differentiate between SSA due to synaptic depression of feedforward connections and SSA due to synaptic depression of recurrent connections. Similar to experimental data, the magnitude of SSA in the model depends on the frequency difference between deviant and standard, probability of the deviant, inter-stimulus interval and input amplitude. In contrast to models based on feedforward depression, our model shows true deviance sensitivity as found in experiments. PMID:28288158

Simulation methods with extended stability for stiff biochemical Kinetics.

PubMed

Rué, Pau; Villà-Freixa, Jordi; Burrage, Kevin

2010-08-11

With increasing computer power, simulating the dynamics of complex systems in chemistry and biology is becoming increasingly routine. The modelling of individual reactions in (bio)chemical systems involves a large number of random events that can be simulated by the stochastic simulation algorithm (SSA). The key quantity is the step size, or waiting time, tau, whose value inversely depends on the size of the propensities of the different channel reactions and which needs to be re-evaluated after every firing event. Such a discrete event simulation may be extremely expensive, in particular for stiff systems where tau can be very short due to the fast kinetics of some of the channel reactions. Several alternative methods have been put forward to increase the integration step size. The so-called tau-leap approach takes a larger step size by allowing all the reactions to fire, from a Poisson or Binomial distribution, within that step. Although the expected value for the different species in the reactive system is maintained with respect to more precise methods, the variance at steady state can suffer from large errors as tau grows. In this paper we extend Poisson tau-leap methods to a general class of Runge-Kutta (RK) tau-leap methods. We show that with the proper selection of the coefficients, the variance of the extended tau-leap can be well-behaved, leading to significantly larger step sizes. The benefit of adapting the extended method to the use of RK frameworks is clear in terms of speed of calculation, as the number of evaluations of the Poisson distribution is still one set per time step, as in the original tau-leap method. The approach paves the way to explore new multiscale methods to simulate (bio)chemical systems.

20 CFR 422.510 - Applications and related forms used in the health insurance for the aged program.

Code of Federal Regulations, 2012 CFR

2012-04-01

... health insurance for the aged program. 422.510 Section 422.510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION ORGANIZATION AND PROCEDURES Applications and Related Forms § 422.510 Applications and related... (see Forms SSA-40, SSA-40A, SSA-40B, SSA-40C, and SSA-40F under § 422.510(a)). (For conditions of...

77 FR 40400 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-09

... wages do not appear in SSA's records of earnings, SSA uses form SSA-7011-F4 to document the alleged... Security earnings record and to process claims for Social Security benefits. We only send Form SSA-7011-F4... Frequency of per response annual burden respondents response (minutes) (hours) SSA-7011-F4 462,000 1 20 154...

Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat

PubMed Central

Nieto-Diego, Javier; Malmierca, Manuel S.

2016-01-01

Stimulus-specific adaptation (SSA) in single neurons of the auditory cortex was suggested to be a potential neural correlate of the mismatch negativity (MMN), a widely studied component of the auditory event-related potentials (ERP) that is elicited by changes in the auditory environment. However, several aspects on this SSA/MMN relation remain unresolved. SSA occurs in the primary auditory cortex (A1), but detailed studies on SSA beyond A1 are lacking. To study the topographic organization of SSA, we mapped the whole rat auditory cortex with multiunit activity recordings, using an oddball paradigm. We demonstrate that SSA occurs outside A1 and differs between primary and nonprimary cortical fields. In particular, SSA is much stronger and develops faster in the nonprimary than in the primary fields, paralleling the organization of subcortical SSA. Importantly, strong SSA is present in the nonprimary auditory cortex within the latency range of the MMN in the rat and correlates with an MMN-like difference wave in the simultaneously recorded local field potentials (LFP). We present new and strong evidence linking SSA at the cellular level to the MMN, a central tool in cognitive and clinical neuroscience. PMID:26950883

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

NASA Astrophysics Data System (ADS)

Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

2015-06-01

Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C14N- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C14N- line scans further show that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces determines their hygroscopic and optical properties. These abundant SSA, whose reactive surfaces absorb inorganic and organic acidic gases in the arctic troposphere, need to be incorporated into atmospheric chemical models.

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere

NASA Astrophysics Data System (ADS)

Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

2015-10-01

Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes in physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased, the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces adsorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the Arctic atmosphere, which need to be incorporated into atmospheric chemical models in the Arctic troposphere.

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

NASA Astrophysics Data System (ADS)

Li, W.

2016-12-01

Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces absorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the arctic atmosphere, which need to be incorporated into atmospheric chemical models in the arctic troposphere.

Orbital State Uncertainty Realism

NASA Astrophysics Data System (ADS)

Horwood, J.; Poore, A. B.

2012-09-01

Fundamental to the success of the space situational awareness (SSA) mission is the rigorous inclusion of uncertainty in the space surveillance network. The *proper characterization of uncertainty* in the orbital state of a space object is a common requirement to many SSA functions including tracking and data association, resolution of uncorrelated tracks (UCTs), conjunction analysis and probability of collision, sensor resource management, and anomaly detection. While tracking environments, such as air and missile defense, make extensive use of Gaussian and local linearity assumptions within algorithms for uncertainty management, space surveillance is inherently different due to long time gaps between updates, high misdetection rates, nonlinear and non-conservative dynamics, and non-Gaussian phenomena. The latter implies that "covariance realism" is not always sufficient. SSA also requires "uncertainty realism"; the proper characterization of both the state and covariance and all non-zero higher-order cumulants. In other words, a proper characterization of a space object's full state *probability density function (PDF)* is required. In order to provide a more statistically rigorous treatment of uncertainty in the space surveillance tracking environment and to better support the aforementioned SSA functions, a new class of multivariate PDFs are formulated which more accurately characterize the uncertainty of a space object's state or orbit. The new distribution contains a parameter set controlling the higher-order cumulants which gives the level sets a distinctive "banana" or "boomerang" shape and degenerates to a Gaussian in a suitable limit. Using the new class of PDFs within the general Bayesian nonlinear filter, the resulting filter prediction step (i.e., uncertainty propagation) is shown to have the *same computational cost as the traditional unscented Kalman filter* with the former able to maintain a proper characterization of the uncertainty for up to *ten times as long* as the latter. The filter correction step also furnishes a statistically rigorous *prediction error* which appears in the likelihood ratios for scoring the association of one report or observation to another. Thus, the new filter can be used to support multi-target tracking within a general multiple hypothesis tracking framework. Additionally, the new distribution admits a distance metric which extends the classical Mahalanobis distance (chi^2 statistic). This metric provides a test for statistical significance and facilitates single-frame data association methods with the potential to easily extend the covariance-based track association algorithm of Hill, Sabol, and Alfriend. The filtering, data fusion, and association methods using the new class of orbital state PDFs are shown to be mathematically tractable and operationally viable.

78 FR 40541 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA)-Match Number 1014

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-05

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2013-0019] Privacy Act of 1974, as Amended; Computer Matching Program (SSA)--Match Number 1014 AGENCY: Social Security Administration (SSA). [[Page 40542

Molecular Diversity of Sea Spray Aerosol Particles: Impact of Ocean Biology on Particle Composition and Hygroscopicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Richard E.; Laskina, Olga; Trueblood, Jonathan V.

The impact of sea spray aerosol (SSA) on climate depends on the size and chemical composition of individual particles that make-up the total SSA ensemble. While the organic fraction of SSA has been characterized from a bulk perspective, there remains a lack of understanding as to the composition of individual particles within the SSA ensemble. To better understand the molecular components within SSA particles and how SSA composition changes with ocean biology, simultaneous measurements of seawater and SSA were made during a month-long mesocosm experiment performed in an ocean-atmosphere facility. Herein, we deconvolute the composition of freshly emitted SSA devoidmore » of anthropogenic and terrestrial influences by characterizing classes of organic compounds as well as specific molecules within individual SSA particles. Analysis of SSA particles show that the diversity of molecules within the organic fraction varies between two size fractions (submicron and supermicron) with contributions from fatty acids, monosaccharides, polysaccharides and siliceous material. Significant changes in the distribution of these compounds within individual particles are observed to coincide with the rise and fall of phytoplankton and bacterial populations within the seawater. Furthermore, water uptake is impacted as shown by hygroscopicity measurements of model systems composed of representative organic compounds. Thus, the how changes in the hygroscopic growth of SSA evolves with composition can be elucidated. Overall, this study provides an important connection between biological processes that control the composition of seawater and changes in single particle composition which will enhances our ability to predict the impact of SSA on climate.« less

Gene Signature in Sessile Serrated Polyps Identifies Colon Cancer Subtype

PubMed Central

Kanth, Priyanka; Bronner, Mary P.; Boucher, Kenneth M.; Burt, Randall W.; Neklason, Deborah W.; Hagedorn, Curt H.; Delker, Don A.

2016-01-01

Sessile serrated colon adenoma/polyps (SSA/Ps) are found during routine screening colonoscopy and may account for 20–30% of colon cancers. However, differentiating SSA/Ps from hyperplastic polyps (HP) with little risk of cancer is challenging and complementary molecular markers are needed. Additionally, the molecular mechanisms of colon cancer development from SSA/Ps are poorly understood. RNA sequencing was performed on 21 SSA/Ps, 10 HPs, 10 adenomas, 21 uninvolved colon and 20 control colon specimens. Differential expression and leave-one-out cross validation methods were used to define a unique gene signature of SSA/Ps. Our SSA/P gene signature was evaluated in colon cancer RNA-Seq data from The Cancer Genome Atlas (TCGA) to identify a subtype of colon cancers that may develop from SSA/Ps. A total of 1422 differentially expressed genes were found in SSA/Ps relative to controls. Serrated polyposis syndrome (n=12) and sporadic SSA/Ps (n=9) exhibited almost complete (96%) gene overlap. A 51-gene panel in SSA/P showed similar expression in a subset of TCGA colon cancers with high microsatellite instability (MSI-H). A smaller seven-gene panel showed high sensitivity and specificity in identifying BRAF mutant, CpG island methylator phenotype high (CIMP-H) and MLH1 silenced colon cancers. We describe a unique gene signature in SSA/Ps that identifies a subset of colon cancers likely to develop through the serrated pathway. These gene panels may be utilized for improved differentiation of SSA/Ps from HPs and provide insights into novel molecular pathways altered in colon cancer arising from the serrated pathway. PMID:27026680

GOCI Yonsei Aerosol Retrieval (YAER) algorithm and validation during the DRAGON-NE Asia 2012 campaign

NASA Astrophysics Data System (ADS)

Choi, Myungje; Kim, Jhoon; Lee, Jaehwa; Kim, Mijin; Park, Young-Je; Jeong, Ukkyo; Kim, Woogyung; Hong, Hyunkee; Holben, Brent; Eck, Thomas F.; Song, Chul H.; Lim, Jae-Hyun; Song, Chang-Keun

2016-04-01

The Geostationary Ocean Color Imager (GOCI) onboard the Communication, Ocean, and Meteorological Satellite (COMS) is the first multi-channel ocean color imager in geostationary orbit. Hourly GOCI top-of-atmosphere radiance has been available for the retrieval of aerosol optical properties over East Asia since March 2011. This study presents improvements made to the GOCI Yonsei Aerosol Retrieval (YAER) algorithm together with validation results during the Distributed Regional Aerosol Gridded Observation Networks - Northeast Asia 2012 campaign (DRAGON-NE Asia 2012 campaign). The evaluation during the spring season over East Asia is important because of high aerosol concentrations and diverse types of Asian dust and haze. Optical properties of aerosol are retrieved from the GOCI YAER algorithm including aerosol optical depth (AOD) at 550 nm, fine-mode fraction (FMF) at 550 nm, single-scattering albedo (SSA) at 440 nm, Ångström exponent (AE) between 440 and 860 nm, and aerosol type. The aerosol models are created based on a global analysis of the Aerosol Robotic Networks (AERONET) inversion data, and covers a broad range of size distribution and absorptivity, including nonspherical dust properties. The Cox-Munk ocean bidirectional reflectance distribution function (BRDF) model is used over ocean, and an improved minimum reflectance technique is used over land. Because turbid water is persistent over the Yellow Sea, the land algorithm is used for such cases. The aerosol products are evaluated against AERONET observations and MODIS Collection 6 aerosol products retrieved from Dark Target (DT) and Deep Blue (DB) algorithms during the DRAGON-NE Asia 2012 campaign conducted from March to May 2012. Comparison of AOD from GOCI and AERONET resulted in a Pearson correlation coefficient of 0.881 and a linear regression equation with GOCI AOD = 1.083 × AERONET AOD - 0.042. The correlation between GOCI and MODIS AODs is higher over ocean than land. GOCI AOD shows better agreement with MODIS DB than MODIS DT. The other GOCI YAER products (AE, FMF, and SSA) show lower correlation with AERONET than AOD, but still show some skills for qualitative use.

GOCI Yonsei Aerosol Retrieval (YAER) Algorithm and Validation During the DRAGON-NE Asia 2012 Campaign

NASA Technical Reports Server (NTRS)

Choi, Myungje; Kim, Jhoon; Lee, Jaehwa; Kim, Mijin; Park, Young-Je; Jeong, Ukkyo; Kim, Woogyung; Hong, Hyunkee; Holben, Brent; Eck, Thomas F.;

3D full-Stokes modeling of the grounding line dynamics of Thwaites Glacier, West Antarctica

NASA Astrophysics Data System (ADS)

Yu, H.; Rignot, E. J.; Morlighem, M.; Seroussi, H. L.

2016-12-01

Thwaites Glacier (TG) is the broadest and second largest ice stream in the West Antarctica. Satellite observations have revealed rapid grounding line retreat and mass loss of this glacier in the past few decades, which has been attributed to the enhanced basal melting in the Amundsen Sea Embayment. With a retrograde bed configuration, TG is on the verge of collapse according to the marine ice sheet instability theory. Here, we use the UCI/JPL Ice Sheet System Model (ISSM) to simulate the grounding line position of TG to determine its stability, rate of retreat and sensitivity to enhanced basal melting using a three-dimensional full-Stokes numerical model. Simulations with simplified models (Higher Order (HO), and Shelfy-Stream Approximation (SSA)) are also conducted for comparison. We first validate our full Stokes model by conducting MISMIP3D experiments. Then we applied the model to TG using new bed elevation dataset combining IceBridge (OIB) gravity data, OIB ice thickness, ice flow vectors from interferometry and a mass conservation method at 450 m spacing. Basal friction coefficient and ice rheology of floating ice are inferred to match observed surface velocity. We find that the grounding line is capable of retreating at rate of 1km/yr under current forcing and that the glacier's sensitivity to melt is higher in the Stokes model than HO or SSA, which means that projections using SSA or HO might underestimate the future rate of retreat of the glacier. This work has been performed at UC Irvine and Caltech's Jet Propulsion Laboratory under a contract with NASA's Cryospheric Science Program.

Dynamic characterisation of the specific surface area for fracture networks

NASA Astrophysics Data System (ADS)

Cvetkovic, V.

2017-12-01

One important application of chemical transport is geological disposal of high-level nuclear waste for which crystalline rock is a prime candidate for instance in Scandinavia. Interconnected heterogeneous fractures of sparsely fractured rock such as granite, act as conduits for transport of dissolved tracers. Fluid flow is known to be highly channelized in such rocks. Channels imply narrow flow paths, adjacent to essentially stagnant water in the fracture and/or the rock matrix. Tracers are transported along channelised flow paths and retained by minerals and/or stagnant water, depending on their sorption properties; this mechanism is critical for rocks to act as a barrier and ultimately provide safety for a geological repository. The sorbing tracers are retained by diffusion and sorption on mineral surfaces, whereas non-sorbing tracers can be retained only by diffusion into stagnant water of fractures. The retention and transport properties of a sparsely fractured rock will primarily depend on the specific surface area (SSA) of the fracture network which is determined by the heterogeneous structure and flow. The main challenge when characterising SSA on the field-scale is its dependence on the flow dynamics. We first define SSA as a physical quantity and clarify its importance for chemical transport. A methodology for dynamic characterisation of SSA in fracture networks is proposed that relies on three sets of data: i) Flow rate data as obtained by a flow logging procedure; ii) transmissivity data as obtained by pumping tests; iii) fracture network data as obtained from outcrop and geophysical observations. The proposed methodology utilises these data directly as well as indirectly through flow and particle tracking simulations in three-dimensional discrete fracture networks. The methodology is exemplified using specific data from the Swedish site Laxemar. The potential impact of uncertainties is of particular significance and is illustrated for radionuclide attenuation. Effects of internal fracture heterogeneity vs fracture network heterogeneity, and of rock deformation, on the statistical properties of SSA are briefly discussed.

Sea spray aerosol chemical composition: elemental and molecular mimics for laboratory studies of heterogeneous and multiphase reactions.

PubMed

Bertram, Timothy H; Cochran, Richard E; Grassian, Vicki H; Stone, Elizabeth A

2018-04-03

Sea spray aerosol particles (SSA), formed through wave breaking at the ocean surface, contribute to natural aerosol particle concentrations in remote regions of Earth's atmosphere, and alter the direct and indirect effects of aerosol particles on Earth's radiation budget. In addition, sea spray aerosol serves as suspended surface area that can catalyze trace gas reactions. It has been shown repeatedly that sea spray aerosol is heavily enriched in organic material compared to the surface ocean. The selective enrichment of organic material complicates the selection of representative molecular mimics of SSA for laboratory or computational studies. In this review, we first provide a short introduction to SSA formation processes and discuss chemical transformations of SSA that occur in polluted coastal regions and remote pristine air. We then focus on existing literature of the chemical composition of nascent SSA generated in controlled laboratory experiments and field investigations. We combine the evidence on the chemical properties of nascent SSA with literature measurements of SSA water uptake to assess SSA molecular composition and liquid water content. Efforts to speciate SSA organic material into molecular classes and specific molecules have led to the identification of saccharides, alkanes, free fatty acids, anionic surfactants, dicarboxylic acids, amino acids, proteinaceous matter, and other large macromolecules. However to date, less than 25% of the organic mass of nascent SSA has been quantified at a molecular level. As discussed here, quantitative measurements of size resolved elemental ratios, combined with determinations of water uptake properties, provides unique insight on the concentration of ions within SSA as a function of particle size, pointing to a controlling role for relative humidity and the hygroscopicity of SSA organic material at small particle diameters.

Regularization of Mars Reconnaissance Orbiter CRISM along-track oversampled hyperspectral imaging observations of Mars

NASA Astrophysics Data System (ADS)

Kreisch, C. D.; O'Sullivan, J. A.; Arvidson, R. E.; Politte, D. V.; He, L.; Stein, N. T.; Finkel, J.; Guinness, E. A.; Wolff, M. J.; Lapôtre, M. G. A.

2017-01-01

Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) hyperspectral image data have been acquired in an along-track oversampled (ATO) mode with the intent of processing the data to better than the nominal ∼18 m/pixel ground resolution. We have implemented an iterative maximum log-likelihood method (MLM) that utilizes the instrument spectral and spatial transfer functions and includes a penalty function to regularize the data. Products are produced both in sensor space and as projected hyperspectral image cubes at 12 m/pixel. Preprocessing steps include retrieval of surface single scattering albedos (SSA) using the Hapke Function and DISORT-based radiative modeling of atmospheric gases and aerosols. Resultant SSA cubes are despiked to remove extrema and tested to ensure that the remaining data are Poisson-distributed, an underlying assumption for the MLM algorithm implementation. Two examples of processed ATO data sets are presented. ATO0002EC79 covers the route taken by the Curiosity rover during its initial ascent of Mount Sharp in Gale Crater. SSA data are used to model mineral abundances and grain sizes predicted to be present in the Namib barchan sand dune sampled and analyzed by Curiosity. CRISM based results compare favorably to in situ results derived from Curiosity's measurement campaign. ATO0002DDF9 covers Marathon Valley on the Cape Tribulation rim segment of Endeavour Crater. SSA spectra indicate the presence of a minor component of Fe3+ and Mg2+ smectites on the valley floor and walls. Localization to 12 m/pixel provided the detailed spatial information needed for the Opportunity rover to traverse to and characterize those outcrops that have the deepest absorptions. The combination of orbital and rover-based data show that the smectite-bearing outcrops in Marathon Valley are impact breccias that are basaltic in composition and that have been isochemically altered in a low water to rock environment.

Overview of Human-Centric Space Situational Awareness (SSA) Science and Technology (S&T)

NASA Astrophysics Data System (ADS)

Ianni, J.; Aleva, D.; Ellis, S.

2012-09-01

A number of organizations, within the government, industry, and academia, are researching ways to help humans understand and react to events in space. The problem is both helped and complicated by the fact that there are numerous data sources that need to be planned (i.e., tasked), collected, processed, analyzed, and disseminated. A large part of the research is in support of the Joint Space Operational Center (JSpOC), National Air and Space Intelligence Center (NASIC), and similar organizations. Much recent research has been specifically targeting the JSpOC Mission System (JMS) which has provided a unifying software architecture. This paper will first outline areas of science and technology (S&T) related to human-centric space situational awareness (SSA) and space command and control (C2) including: 1. Object visualization - especially data fused from disparate sources. Also satellite catalog visualizations that convey the physical relationships between space objects. 2. Data visualization - improve data trend analysis as in visual analytics and interactive visualization; e.g., satellite anomaly trends over time, space weather visualization, dynamic visualizations 3. Workflow support - human-computer interfaces that encapsulate multiple computer services (i.e., algorithms, programs, applications) into a 4. Command and control - e.g., tools that support course of action (COA) development and selection, tasking for satellites and sensors, etc. 5. Collaboration - improve individuals or teams ability to work with others; e.g., video teleconferencing, shared virtual spaces, file sharing, virtual white-boards, chat, and knowledge search. 6. Hardware/facilities - e.g., optimal layouts for operations centers, ergonomic workstations, immersive displays, interaction technologies, and mobile computing. Secondly we will provide a survey of organizations working these areas and suggest where more attention may be needed. Although no detailed master plan exists for human-centric SSA and C2, we see little redundancy among the groups supporting SSA human factors at this point.

Streptomyces amphotericinicus sp. nov., an amphotericin-producing actinomycete isolated from the head of an ant (Camponotus japonicus Mayr).

PubMed

Cao, Tingting; Mu, Shan; Lu, Chang; Zhao, Shanshan; Li, Dongmei; Yan, Kai; Xiang, Wensheng; Liu, Chongxi

2017-12-01

A novel actinomycete, designated strain 1H-SSA8 T , was isolated from the head of an ant (Camponotus japonicus Mayr) and was found to produce amphotericin. A polyphasic approach was employed to determine the status of strain 1H-SSA8 T . Morphological and chemotaxonomic characteristics were consistent with those of members of the genus Streptomyces. The menaquinones detected were MK-9(H6), MK-9(H8) and MK-9(H4). The phospholipid profile consisted of diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine and phosphatidylinositol mannoside. The major fatty acids were identified as iso-C16 : 0, C16 : 0, C15 : 0 and anteiso-C15 : 0. Analysis of the 16S rRNA gene sequence showed that strain 1H-SSA8 T belongs to the genus Streptomyces with high sequence similarity to Streptomyces ramulosus NRRL B-2714 T (99.2 %). Two tree-making algorithms based on 16S rRNA gene sequences showed that the isolate formed a phyletic line with Streptomyces himastatinicus ATCC 53653 T (98.7 %). The MLSA utilizing partial sequences of the housekeeping genes (atpD, gyrB, recA, rpoB and trpB) also supported the position. However, evolutionary distances were higher than the 0.007 MLSA evolutionary distance threshold proposed for species-level relatedness. Moreover, the low level of DNA-DNA relatedness and phenotypic differences allowed the novel isolate to be differentiated from its most closely related strain S. ramulosus NRRL B-2714 T and strain S. himastatinicus ATCC 53653 T . It is concluded that the organism can be classified as representing a novel species of the genus Streptomyces, for which the name Streptomyces amphotericinicus sp. nov. is proposed. The type strain is 1H-SSA8 T (=CGMCC 4.7350 T =DSM 103128 T ).

Sea Spray Aerosol Production over the North Atlantic

NASA Astrophysics Data System (ADS)

Bates, T. S.; Quinn, P.

2017-12-01

Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

Properties of Cement Mortar Produced from Mixed Waste Materials with Pozzolanic Characteristics.

PubMed

Yen, Chi-Liang; Tseng, Dyi-Hwa; Wu, Yue-Ze

2012-07-01

Waste materials with pozzolanic characteristics, such as sewage sludge ash (SSA), coal combustion fly ash (FA), and granulated blast furnace slag (GBS), were reused as partial cement replacements for making cement mortar in this study. Experimental results revealed that with dual replacement of cement by SSA and GBS and triple replacement by SSA, FA, and GBS at 50% of total cement replacement, the compressive strength (Sc) of the blended cement mortars at 56 days was 93.7% and 92.9% of the control cement mortar, respectively. GBS had the highest strength activity index value and could produce large amounts of CaO to enhance the pozzolanic activity of SSA/FA and form calcium silicate hydrate gels to fill the capillary pores of the cement mortar. Consequently, the Sc development of cement mortar with GBS replacement was better than that without GBS, and the total pore volume of blended cement mortars with GBS/SSA replacement was less than that with FA/SSA replacement. In the cement mortar with modified SSA and GBS at 70% of total cement replacement, the Sc at 56 days was 92.4% of the control mortar. Modifying the content of calcium in SSA also increased its pozzolanic reaction. CaCl(2) accelerated the pozzolanic activity of SSA better than lime did. Moreover, blending cement mortars with GBS/SSA replacement could generate more monosulfoaluminate to fill capillary pores.

Properties of Cement Mortar Produced from Mixed Waste Materials with Pozzolanic Characteristics

PubMed Central

Yen, Chi-Liang; Tseng, Dyi-Hwa; Wu, Yue-Ze

2012-01-01

Abstract Waste materials with pozzolanic characteristics, such as sewage sludge ash (SSA), coal combustion fly ash (FA), and granulated blast furnace slag (GBS), were reused as partial cement replacements for making cement mortar in this study. Experimental results revealed that with dual replacement of cement by SSA and GBS and triple replacement by SSA, FA, and GBS at 50% of total cement replacement, the compressive strength (Sc) of the blended cement mortars at 56 days was 93.7% and 92.9% of the control cement mortar, respectively. GBS had the highest strength activity index value and could produce large amounts of CaO to enhance the pozzolanic activity of SSA/FA and form calcium silicate hydrate gels to fill the capillary pores of the cement mortar. Consequently, the Sc development of cement mortar with GBS replacement was better than that without GBS, and the total pore volume of blended cement mortars with GBS/SSA replacement was less than that with FA/SSA replacement. In the cement mortar with modified SSA and GBS at 70% of total cement replacement, the Sc at 56 days was 92.4% of the control mortar. Modifying the content of calcium in SSA also increased its pozzolanic reaction. CaCl2 accelerated the pozzolanic activity of SSA better than lime did. Moreover, blending cement mortars with GBS/SSA replacement could generate more monosulfoaluminate to fill capillary pores. PMID:22783062

20 CFR 422.710 - Procedures SSA will follow.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 422.710 Employees' Benefits SOCIAL SECURITY ADMINISTRATION ORGANIZATION AND PROCEDURES Use of SSA Telephone Lines § 422.710 Procedures SSA will follow. SSA component(s) that plan to listen-in to or record... written certification of need to the Commissioner of Social Security or designee at least 30 days before...

20 CFR 422.710 - Procedures SSA will follow.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 422.710 Employees' Benefits SOCIAL SECURITY ADMINISTRATION ORGANIZATION AND PROCEDURES Use of SSA Telephone Lines § 422.710 Procedures SSA will follow. SSA component(s) that plan to listen-in to or record... written certification of need to the Commissioner of Social Security or designee at least 30 days before...

78 FR 69926 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Centers for Medicare & Medicaid...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-21

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76 FR 21091 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Centers for Medicare & Medicaid...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

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UV-Vis-IR spectral complex refractive indices and optical properties of brown carbon aerosol from biomass burning

NASA Astrophysics Data System (ADS)

Sumlin, Benjamin J.; Heinson, Yuli W.; Shetty, Nishit; Pandey, Apoorva; Pattison, Robert S.; Baker, Stephen; Hao, Wei Min; Chakrabarty, Rajan K.

2018-02-01

Constraining the complex refractive indices, optical properties and size of brown carbon (BrC) aerosols is a vital endeavor for improving climate models and satellite retrieval algorithms. Smoldering wildfires are the largest source of primary BrC, and fuel parameters such as moisture content, source depth, geographic origin, and fuel packing density could influence the properties of the emitted aerosol. We measured in situ spectral (375-1047 nm) optical properties of BrC aerosols emitted from smoldering combustion of Boreal and Indonesian peatlands across a range of these fuel parameters. Inverse Lorenz-Mie algorithms used these optical measurements along with simultaneously measured particle size distributions to retrieve the aerosol complex refractive indices (m = n + iκ). Our results show that the real part n is constrained between 1.5 and 1.7 with no obvious functionality in wavelength (λ), moisture content, source depth, or geographic origin. With increasing λ from 375 to 532 nm, κ decreased from 0.014 to 0.003, with corresponding increase in single scattering albedo (SSA) from 0.93 to 0.99. The spectral variability of κ follows the Kramers-Kronig dispersion relation for a damped harmonic oscillator. For λ ≥ 532 nm, both κ and SSA showed no spectral dependency. We discuss differences between this study and previous work. The imaginary part κ was sensitive to changes in FPD, and we hypothesize mechanisms that might help explain this observation.

Mechanical and physical properties of cement blended with sewage sludge ash.

PubMed

Garcés, P; Pérez Carrión, M; García-Alcocel, E; Payá, J; Monzó, J; Borrachero, M V

2008-12-01

The aim of this paper is to evaluate the compatibility of sewage sludge ash (SSA) with various types of commercially available cements (CEM I and CEM II types, cements with several proportions of clinker). The behaviour of mortars fabricated with various percentages (10-30% by weight) of the cement replaced by SSA has been analyzed in terms of workability, mechanical strength, porosity and shrinkage/expansion. SSA exhibits moderate pozzolanic activity; the highest compressive strengths were obtained with 10% of the cement replaced by SSA. The CEM II/B-M (V-LL) 42.5R cement is considered ideal for preparing mortars containing SSA. Shrinkage data demonstrate that sulphates present in SSA are not reactive towards cement.

77 FR 33547 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Centers for Medicare and Medicaid...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-06

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78 FR 36291 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-17

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Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-03

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Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-01

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BOREAS HYD-1 Volumetric Soil Moisture Data

NASA Technical Reports Server (NTRS)

Cuenca, Richard H.; Kelly, Shaun F.; Stangel, David E.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

2000-01-01

The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-1 team made measurements of volumetric soil moisture at the Southern Study Area (SSA) and Northern Study Area (NSA) tower flux sites in 1994 and at selected tower flux sites in 1995-97. Different methods were used to collect these measurements, including neutron probe and manual and automated Time Domain Reflectometry (TDR). In 1994, the measurements were made every other day at the NSA-OJP (Old Jack Pine), NSA-YJP (Young Jack Pine), NSA-OBS (Old Black Spruce), NSA-Fen, SSA-OJP, SSA-YJP, SSA-Fen, SSA-YA (Young Aspen), and SSA-OBS sites. In 1995-97, when automated equipment was deployed at NSA-OJP, NSA-YJP, NSA-OBS, SSA-OBS, and SSA-OA (Old Aspen), the measurements were made as often as every hour. The data are stored in tabular ASCII files. The volumetric soil moisture data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

Sea Spray Aerosol Production in the North Atlantic: A Comparison from 4 Cruises in 3 Seasons

NASA Astrophysics Data System (ADS)

Bates, T. S.; Quinn, P.

2016-12-01

Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

Inland Sea Spray Aerosol Transport and Incomplete Chloride Depletion: Varying Degrees of Reactive Processing Observed during SOAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bondy, Amy L.; Wang, Bingbing; Laskin, Alexander

Multiphase reactions involving sea spray aerosol (SSA) impact trace gases budgets in coastal regions by acting as a reservoir for oxidized nitrogen and sulfur species, as well as a source of halogen gases (HCl, ClNO2, etc.). While most studies of multiphase reactions on SSA have focused on marine environments, far less is known about SSA transported inland. Herein, single particle measurements of SSA are reported at a site > 320 km from the Gulf of Mexico, with transport times of 7-68 h. Samples were collected during the Southern Oxidant and Aerosol Study (SOAS) in June-July 2013 near Centreville, Alabama. SSAmore » was observed in 93% of 42 time periods analyzed. During two marine air mass periods, SSA represented significant number fractions of particles in the accumulation (0.2-1.0 μm, 11%) and coarse (1.0-10.0 μm, 35%) modes. Chloride content of SSA particles ranged from full to partial depletion, with 24% of SSA particles containing chloride (mole fraction of Cl/Na > 0.1, 90% chloride depletion). Both the frequent observation of SSA at an inland site and the range of chloride depletion observed, suggest that SSA may represent an underappreciated inland sink for NOx/SO2 and source of halogen gases.« less

A systematic review of physical activity policy recommendations and interventions for people with mental health problems in Sub-Saharan African countries

PubMed Central

Vancampfort, Davy; Stubbs, Brendon; De Hert, Marc; du Plessis, Christy; Gbiri, Caleb Ademola Omuwa; Kibet, Jepkemoi; Wanyonyi, Nancy; Mugisha, James

2017-01-01

Introduction There is a need for interventions to address the escalating mental health burden in Sub-Saharan Africa (SSA). Implementation of physical activity (PA) within the rehabilitation of people with mental health problems (PMHP) could reduce the burden and facilitate recovery. The objective of the current review was to explore (1) the role of PA within mental health policies of SSA countries, and (2) the current research evidence for PA to improve mental health in SSA. Methods We screened the Mental Health Atlas and MiNDbank for mental health policies in SSA countries and searched PubMed for relevant studies on PA in PMHP in SSA. Results Sixty-nine percent (=33/48) of SSA countries have a dedicated mental health policy. Two of 22 screened mental health policies included broad physical activity recommendations. There is clear evidence for the role of PA in the prevention and rehabilitation of depression in SSA. Conclusion Despite the existing evidence, PA is largely a neglected rehabilitation modality in the mental health care systems of SSA. Continued education of existing staff, training of specialized professionals and integration of PA for mental health in public health awareness programs are needed to initiate and improve PA programs within the mental health care systems of SSA. PMID:28491235

A systematic review of physical activity policy recommendations and interventions for people with mental health problems in Sub-Saharan African countries.

PubMed

Vancampfort, Davy; Stubbs, Brendon; De Hert, Marc; du Plessis, Christy; Gbiri, Caleb Ademola Omuwa; Kibet, Jepkemoi; Wanyonyi, Nancy; Mugisha, James

2017-01-01

There is a need for interventions to address the escalating mental health burden in Sub-Saharan Africa (SSA). Implementation of physical activity (PA) within the rehabilitation of people with mental health problems (PMHP) could reduce the burden and facilitate recovery. The objective of the current review was to explore (1) the role of PA within mental health policies of SSA countries, and (2) the current research evidence for PA to improve mental health in SSA. We screened the Mental Health Atlas and MiNDbank for mental health policies in SSA countries and searched PubMed for relevant studies on PA in PMHP in SSA. Sixty-nine percent (=33/48) of SSA countries have a dedicated mental health policy. Two of 22 screened mental health policies included broad physical activity recommendations. There is clear evidence for the role of PA in the prevention and rehabilitation of depression in SSA. Despite the existing evidence, PA is largely a neglected rehabilitation modality in the mental health care systems of SSA. Continued education of existing staff, training of specialized professionals and integration of PA for mental health in public health awareness programs are needed to initiate and improve PA programs within the mental health care systems of SSA.

Octreotide and pasireotide (dis)similarly inhibit pituitary tumor cells in vitro.

PubMed

Ibáñez-Costa, Alejandro; Rivero-Cortés, Esther; Vázquez-Borrego, Mari C; Gahete, Manuel D; Jiménez-Reina, Luis; Venegas-Moreno, Eva; de la Riva, Andrés; Arráez, Miguel Ángel; González-Molero, Inmaculada; Schmid, Herbert A; Maraver-Selfa, Silvia; Gavilán-Villarejo, Inmaculada; García-Arnés, Juan Antonio; Japón, Miguel A; Soto-Moreno, Alfonso; Gálvez, María A; Luque, Raúl M; Castaño, Justo P

2016-11-01

Somatostatin analogs (SSA) are the mainstay of pharmacological treatment for pituitary adenomas. However, some patients escape from therapy with octreotide, a somatostatin receptor 2 (sst2)-preferring SSA, and pasireotide, a novel multi-sst-preferring SSA, may help to overcome this problem. It has been proposed that correspondence between sst1-sst5 expression pattern and SSA-binding profile could predict patient's response. To explore the cellular/molecular features associated with octreotide/pasireotide response, we performed a parallel comparison of their in vitro effects, evaluating sst1-sst5 expression, intracellular Ca 2+ signaling ([Ca 2+ ] i ), hormone secretion and cell viability, in a series of 85 pituitary samples. Somatotropinomas expressed sst5>sst2, yet octreotide reduced [Ca 2+ ] i more efficiently than pasireotide, while both SSA similarly decreased growth hormone release/expression and viability. Corticotropinomas predominantly expressed sst5, but displayed limited response to pasireotide, while octreotide reduced functional endpoints. Non-functioning adenomas preferentially expressed sst3 but, surprisingly, both SSA increased cell viability. Prolactinomas mainly expressed sst1 but were virtually unresponsive to SSA. Finally, both SSA decreased [Ca 2+ ] i in normal pituitaries. In conclusion, both SSA act in vitro on pituitary adenomas exerting both similar and distinct effects; however, no evident correspondence was found with the sst1-sst5 profile. Thus, it seems plausible that additional factors, besides the simple abundance of a given sst, critically influence the SSA response. © 2016 Society for Endocrinology.

The Case for GEO Hosted SSA Payloads

NASA Astrophysics Data System (ADS)

Welsch, C.; Armand, B.; Repp, M.; Robinson, A.

2014-09-01

Space situational awareness (SSA) in the geosynchronous earth orbit (GEO) belt presents unique challenges, and given the national importance and high value of GEO satellites, is increasingly critical as space becomes more congested and contested. Space situational awareness capabilities can serve as an effective deterrent against potential adversaries if they provide accurate, timely, and persistent information and are resilient to the threat environment. This paper will demonstrate how simple optical SSA payloads hosted on GEO commercial and government satellites can complement the SSA mission and data provided by Space-Based Space Surveillance (SBSS) and the Geosynchronous Space Situational Awareness Program (GSSAP). GSSAP is built by Orbital Sciences Corporation and launched on July 28, 2014. Analysis performed for this paper will show how GEO hosted SSA payloads, working in combination with SBSS and GSSAP, can increase persistence and timely coverage of high value assets in the GEO belt. The potential to further increase GEO object identification and tracking accuracy by integrating SSA data from multiple sources across different viewing angles including GEO hosted SSA sources will be addressed. Hosting SSA payloads on GEO platforms also increases SSA mission architecture resiliency as the sensors are by distributed across multiple platforms including commercial platforms. This distributed architecture presents a challenging target for an adversary to attempt to degrade or disable. We will present a viable concept of operations to show how data from hosted SSA sensors could be integrated with SBSS and GSSAP data to present a comprehensive and more accurate data set to users. Lastly, we will present an acquisition approach using commercial practices and building on lessons learned from the Commercially Hosted Infra Red Payload CHIRP to demonstrate the affordability of GEO hosted SSA payloads.

The OMI Aerosol Absorption Product: An A-train application

NASA Astrophysics Data System (ADS)

Torres, O.; Jethva, H. T.; Ahn, C.

2017-12-01

Because of the uniquely large sensitivity of satellite-measured near-UV radiances to absorption by desert dust, carbonaceous and volcanic ash aerosols, observations by a variety of UV-capable sensors have been routinely used over the last forty years in both qualitative and quantitative applications for estimating the absorption properties of these aerosol types. In this presentation we will discuss a multi-sensor application involving observations from A-train sensors OMI, AIRS and CALIOP for the creation of a 13-year record of aerosol optical depth (AOD) and single scattering albedo (SSA). Determination of aerosol type, in terms of particle size distribution and refractive index, is an important algorithmic step that requires using external information. AIRS CO measurements are used as carbonaceous aerosols tracer to differentiate this aerosol type from desert dust. On the other hand, the height of the absorbing aerosol layer, an important parameter in UV aerosol retrievals, is prescribed using a CALIOP-based climatology. The combined use of these observations in the developments of the OMI long-term AOD/SSA record will be discussed along with an evaluation of retrieval results using independent observations.

Stochastic subspace identification for operational modal analysis of an arch bridge

NASA Astrophysics Data System (ADS)

Loh, Chin-Hsiung; Chen, Ming-Che; Chao, Shu-Hsien

2012-04-01

In this paer the application of output-only system identification technique, known as Stochastic Subspace Identification (SSI) algorithms, for civil infrastructures is carried out. The ability of covariance driven stochastic subspace identification (SSI-COV) was proved through the analysis of the ambient data of an arch bridge under operational condition. A newly developed signal processing technique, Singular Spectrum analysis (SSA), capable to smooth noisy signals, is adopted for pre-processing the recorded data before the SSI. The conjunction of SSA and SSICOV provides a useful criterion for the system order determination. With the aim of estimating accurate modal parameters of the structure in off-line analysis, a stabilization diagram is constructed by plotting the identified poles of the system with increasing the size of data Hankel matrix. Identification task of a real structure, Guandu Bridge, is carried out to identify the system natural frequencies and mode shapes. The uncertainty of the identified model parameters from output-only measurement of the bridge under operation condition, such as temperature and traffic loading conditions, is discussed.

Enhanced electrical power generation using flame-oxidized stainless steel anode in microbial fuel cells and the anodic community structure.

PubMed

Yamashita, Takahiro; Ishida, Mitsuyoshi; Asakawa, Shiho; Kanamori, Hiroyuki; Sasaki, Harumi; Ogino, Akifumi; Katayose, Yuichi; Hatta, Tamao; Yokoyama, Hiroshi

2016-01-01

Carbon-based materials are commonly used as anodes in microbial fuel cells (MFCs), whereas metal and metal-oxide-based materials are not used frequently because of low electrical output. Stainless steel is a low-cost material with high conductivity and physical strength. In this study, we investigated the power generation using flame-oxidized (FO) stainless steel anodes (SSAs) in single-chambered air-cathode MFCs. The FO-SSA performance was compared to the performance of untreated SSA and carbon cloth anode (CCA), a common carbonaceous electrode. The difference in the anodic community structures was analyzed using high-throughput sequencing of the V4 region in 16S rRNA gene. Flame oxidation of SSA produced raised node-like sites, predominantly consisting of hematite (Fe2O3), on the surface, as determined by X-ray diffraction spectroscopy. The flame oxidation enhanced the maximum power density (1063 mW/m(2)) in MFCs, which was 184 and 24 % higher than those for untreated SSA and CCA, respectively. The FO-SSA exhibited 8.75 and 2.71 times higher current production than SSA and CCA, respectively, under potentiostatic testing conditions. Bacteria from the genus Geobacter were detected at a remarkably higher frequency in the biofilm formed on the FO-SSA (8.8-9.2 %) than in the biofilms formed on the SSA and CCA (0.7-1.4 %). Bacterial species closely related to Geobacter metallireducens (>99 % identity in the gene sequence) were predominant (93-96 %) among the genus Geobacter in the FO-SSA biofilm, whereas bacteria with a 100 % identity to G. anodireducens were abundant (>55 %) in the SSA and CCA biofilms. This is the first demonstration of power generation using an FO-SSA in MFCs. Flame oxidation of the SSA enhances electricity production in MFCs, which is higher than that with the common carbonaceous electrode, CCA. The FO-SSA is not only inexpensive but also can be prepared using a simple method. To our knowledge, this study reveals, for the first time, that the predominant Geobacter species in the biofilm depends on the anode material. The high performance of the FO-SSA could result from the particularly high population of bacteria closely related to G. metallireducens in the biofilm.

Aerosol Retrieval from Multiangle Multispectral Photopolarimetric Measurements: Importance of Spectral Range and Angular Resolution

NASA Technical Reports Server (NTRS)

Wu, L.; Hasekamp, O.; Van Diedenhoven, B.; Cairns, B.

2015-01-01

We investigated the importance of spectral range and angular resolution for aerosol retrieval from multiangle photopolarimetric measurements over land. For this purpose, we use an extensive set of simulated measurements for different spectral ranges and angular resolutions and subsets of real measurements of the airborne Research Scanning Polarimeter (RSP) carried out during the PODEX and SEAC4RS campaigns over the continental USA. Aerosol retrievals performed from RSP measurements show good agreement with ground-based AERONET measurements for aerosol optical depth (AOD), single scattering albedo (SSA) and refractive index. Furthermore, we found that inclusion of shortwave infrared bands (1590 and/or 2250 nm) significantly improves the retrieval of AOD, SSA and coarse mode microphysical properties. However, accuracies of the retrieved aerosol properties do not improve significantly when more than five viewing angles are used in the retrieval.

20 CFR 422.705 - When SSA employees may listen-in to or record telephone conversations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false When SSA employees may listen-in to or record telephone conversations. 422.705 Section 422.705 Employees' Benefits SOCIAL SECURITY ADMINISTRATION ORGANIZATION AND PROCEDURES Use of SSA Telephone Lines § 422.705 When SSA employees may listen-in to or record...

20 CFR 422.705 - When SSA employees may listen-in to or record telephone conversations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false When SSA employees may listen-in to or record telephone conversations. 422.705 Section 422.705 Employees' Benefits SOCIAL SECURITY ADMINISTRATION ORGANIZATION AND PROCEDURES Use of SSA Telephone Lines § 422.705 When SSA employees may listen-in to or record...

Properties of a magnetorheological semi-active vibration absorber

NASA Astrophysics Data System (ADS)

Albanese, Anne-Marie; Cunefare, Kenneth A.

2003-07-01

A tuned vibration absorber (TVA) is a spring-damper-mass system used in many industries for the suppression of a specific vibration frequency. A state-switched absorber (SSA) is similar to a TVA, except that one or more components in the SSA is able to instantaneously and discretely change properties, thus increasing the effective bandwidth of vibration suppression. The components responsible for bandwidth increase are called switching elements. In order to design a replacement SSA for the classic TVA, the SSA must operate in the appropriate frequency range, be lightweight and compact. An optimal SSA will also have a maximal frequency range that it can switch between. This paper discusses the development of a magnetorheological (MR) silicone gel used as the SSA switching element, the SSA geometry selected to maintain a magnetic flux path, and the contribution of the magnet-mass to frequency shifting. The MR gel is iron-doped silicone, cured in the presence of a magnetic field. During operation, the applied magnetic flux is modified to change the natural frequency. Since a flux path through the switching element is required, a steel flux path was incorporated as part of the SSA design. The SSA is desgined to operate below 100 Hz. An MR elastometer with 35% iron by volume yielded the most tunable results, where the minimum natural frequency was found to be 45 Hz, and the natural frequency was tunable up to 183 Hz.

The relationship of the lipoprotein SsaB, manganese and superoxide dismutase in Streptococcus sanguinis virulence for endocarditis.

PubMed

Crump, Katie E; Bainbridge, Brian; Brusko, Sarah; Turner, Lauren S; Ge, Xiuchun; Stone, Victoria; Xu, Ping; Kitten, Todd

2014-06-01

Streptococcus sanguinis colonizes teeth and is an important cause of infective endocarditis. Our prior work showed that the lipoprotein SsaB is critical for S. sanguinis virulence for endocarditis and belongs to the LraI family of conserved metal transporters. In this study, we demonstrated that an ssaB mutant accumulates less manganese and iron than its parent. A mutant lacking the manganese-dependent superoxide dismutase, SodA, was significantly less virulent than wild-type in a rabbit model of endocarditis, but significantly more virulent than the ssaB mutant. Neither the ssaB nor the sodA mutation affected sensitivity to phagocytic killing or efficiency of heart valve colonization. Animal virulence results for all strains could be reproduced by growing bacteria in serum under physiological levels of O(2). SodA activity was reduced, but not eliminated in the ssaB mutant in serum and in rabbits. Growth of the ssaB mutant in serum was restored upon addition of Mn(2+) or removal of O(2). Antioxidant supplementation experiments suggested that superoxide and hydroxyl radicals were together responsible for the ssaB mutant's growth defect. We conclude that manganese accumulation mediated by the SsaB transport system imparts virulence by enabling cell growth in oxygen through SodA-dependent and independent mechanisms. © 2014 John Wiley & Sons Ltd.

The Relationship of the Lipoprotein SsaB, Manganese, and Superoxide Dismutase in Streptococcus sanguinis Virulence for Endocarditis

PubMed Central

Crump, Katie E.; Bainbridge, Brian; Brusko, Sarah; Turner, Lauren S.; Ge, Xiuchun; Stone, Victoria; Xu, Ping; Kitten, Todd

2014-01-01

Summary Streptococcus sanguinis colonizes teeth and is an important cause of infective endocarditis. Our prior work showed that the lipoprotein SsaB is critical for S. sanguinis virulence for endocarditis and belongs to the LraI family of conserved metal transporters. In this study, we demonstrated that an ssaB mutant accumulates less manganese and iron than its parent. A mutant lacking the manganese-dependent superoxide dismutase, SodA, was significantly less virulent than wild-type in a rabbit model of endocarditis, but significantly more virulent than the ssaB mutant. Neither the ssaB nor the sodA mutation affected sensitivity to phagocytic killing or efficiency of heart valve colonization. Animal virulence results for all strains could be reproduced by growing bacteria in serum under physiological levels of O2. SodA activity was reduced, but not eliminated in the ssaB mutant in serum and in rabbits. Growth of the ssaB mutant in serum was restored upon addition of Mn2+ or removal of O2. Antioxidant supplementation experiments suggested that superoxide and hydroxyl radicals were together responsible for the ssaB mutant’s growth defect. We conclude that manganese accumulation mediated by the SsaB transport system imparts virulence by enabling cell growth in oxygen through SodA-dependent and independent mechanisms. PMID:24750294

BOREAS TGB-9 Above-canopy NMHC at SSA-OBS, SSA-OJP, and SSA-OA Sites

NASA Technical Reports Server (NTRS)

Keiser, B. N.; Niki, H.; Young, V. L.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOREAS TGB-9 team collected data in order to inventory and quantify the anthropogenic and biogenic NMHCs over the BOREAS study areas. This data set contains concentration and mixing ratio values for several NMHCs collected at the BOREAS SSA from 27-May-1994 to 15-Sep-1994. The data are provided in tabular ASCII files.

The analysis of a state-switched absorber design concept

NASA Astrophysics Data System (ADS)

Albanese, Anne-Marie; Cunefare, Kenneth

2002-11-01

A tuned vibration absorber (TVA) is a spring-damper-mass system used in many industries for the suppression of a specific vibration frequency, and has application for the suppression of aircraft fuselage vibration. A state-switched absorber (SSA) is similar to a TVA, except that one or more components in the SSA is able to instantaneously and discretely change properties, thus increasing the effective bandwidth of vibration suppression. In order to design a replacement SSA for the classic TVA, the SSA must operate in the appropriate frequency range, be lightweight, and compact. An optimal SSA will also have a maximal frequency range between which it can switch. This paper discusses the development of a magnetorheological (MR) silicone gel used as the SSA switching element, the shape required to maintain a magnetic flux path, and the contribution of the magnet-mass to frequency shifting. The MR gel is iron-doped silicone, cured in the presence of a magnetic field. During operation, the applied magnetic flux is modified to change the natural frequency. The applied flux requirement forces the SSA to be a small ring. The SSA is designed to operate below 100 Hz.

Linear least-squares method for global luminescent oil film skin friction field analysis

NASA Astrophysics Data System (ADS)

Lee, Taekjin; Nonomura, Taku; Asai, Keisuke; Liu, Tianshu

2018-06-01

A data analysis method based on the linear least-squares (LLS) method was developed for the extraction of high-resolution skin friction fields from global luminescent oil film (GLOF) visualization images of a surface in an aerodynamic flow. In this method, the oil film thickness distribution and its spatiotemporal development are measured by detecting the luminescence intensity of the thin oil film. From the resulting set of GLOF images, the thin oil film equation is solved to obtain an ensemble-averaged (steady) skin friction field as an inverse problem. In this paper, the formulation of a discrete linear system of equations for the LLS method is described, and an error analysis is given to identify the main error sources and the relevant parameters. Simulations were conducted to evaluate the accuracy of the LLS method and the effects of the image patterns, image noise, and sample numbers on the results in comparison with the previous snapshot-solution-averaging (SSA) method. An experimental case is shown to enable the comparison of the results obtained using conventional oil flow visualization and those obtained using both the LLS and SSA methods. The overall results show that the LLS method is more reliable than the SSA method and the LLS method can yield a more detailed skin friction topology in an objective way.

Solar Flare Prediction Science-to-Operations: the ESA/SSA SWE A-EFFort Service

NASA Astrophysics Data System (ADS)

Georgoulis, Manolis K.; Tziotziou, Konstantinos; Themelis, Konstantinos; Magiati, Margarita; Angelopoulou, Georgia

2016-07-01

We attempt a synoptical overview of the scientific origins of the Athens Effective Solar Flare Forecasting (A-EFFort) utility and the actions taken toward transitioning it into a pre-operational service of ESA's Space Situational Awareness (SSA) Programme. The preferred method for solar flare prediction, as well as key efforts to make it function in a fully automated environment by coupling calculations with near-realtime data-downloading protocols (from the Solar Dynamics Observatory [SDO] mission), pattern recognition (solar active-region identification) and optimization (magnetic connectivity by simulated annealing) will be highlighted. In addition, the entire validation process of the service will be described, with its results presented. We will conclude by stressing the need for across-the-board efforts and synergistic work in order to bring science of potentially limited/restricted interest into realizing a much broader impact and serving the best public interests. The above presentation was partially supported by the ESA/SSA SWE A-EFFort project, ESA Contract No. 4000111994/14/D/MRP. Special thanks go to the ESA Project Officers R. Keil, A. Glover, and J.-P. Luntama (ESOC), M. Bobra and C. Balmer of the SDO/HMI team at Stanford University, and M. Zoulias at the RCAAM of the Academy of Athens for valuable technical help.

Comparing the use of sewage sludge ash and glass powder in cement mortars.

PubMed

Chen, Zhen; Poon, Chi Sun

2017-06-01

This study explored the suitability of using sewage sludge ash (SSA) and mixed-colored glass powder (MGP) as construction materials in cement mortars. Positive findings from this study may help promote the recycling of waste SSA and MGP in construction works. The results indicated that the SSA decreased while MGP improved the mortar workability. The SSA exhibited very low pozzolanic activity, but the cement mortar prepared with 20% SSA yielded strength values slightly superior to those of the glass mortars due to its water absorption ability. MGP can serve as a pozzolan and when 20% of cement was replaced by MGP, apparent compressive strength gains were found at later curing ages. The SSA could be used to mitigate ASR expansion while the MGP was superior in resisting drying shrinkage.

Evaluation of transplant renal artery blood flow by Doppler sound-spectrum analysis.

PubMed

Reinitz, E R; Goldman, M H; Sais, J; Rittgers, S E; Lee, H M; Mendez-Picon, G; Muakkassa, W F; Barnes, R W

1983-04-01

Doppler ultrasonography sound-spectrum analysis (SSA) was used to evaluate blood flow in the transplanted kidney and its renal artery. Seven patients with posttransplant hypertension and a bruit over the transplanted kidney were screened for renal artery stenosis (RAS). In five patients, RAS was diagnosed by SSA, and in two it was not. These findings were confirmed by subsequent angiography in all patients. Three patients studied after surgical correction of their RAS had improvement in their SSA patterns. Fourteen hypertensive patients with a cause other than RAS were evaluated by SSA. None of them had SSA findings suggestive of RAS. Doppler ultrasonography with SSA is an effective, noninvasive technique of monitoring transplant renal blood flow, especially in the screening of hypertensive transplant recipients for transplant RAS.

Retrieving the Height of Smoke and Dust Aerosols by Synergistic Use of VIIRS, OMPS, and CALIOP Observations

NASA Technical Reports Server (NTRS)

Lee, Jaehwa; Hsu, N. Christina; Bettenhausen, Corey; Sayer, Andrew M.; Seftor, Colin J.; Jeong, Myeong-Jae

2015-01-01

Aerosol Single scattering albedo and Height Estimation (ASHE) algorithm was first introduced in Jeong and Hsu (2008) to provide aerosol layer height as well as single scattering albedo (SSA) for biomass burning smoke aerosols. One of the advantages of this algorithm was that the aerosol layer height can be retrieved over broad areas, which had not been available from lidar observations only. The algorithm utilized aerosol properties from three different satellite sensors, i.e., aerosol optical depth (AOD) and Ångström exponent (AE) from Moderate Resolution Imaging Spectroradiometer (MODIS), UV aerosol index (UVAI) from Ozone Monitoring Instrument (OMI), and aerosol layer height from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Here, we extend the application of the algorithm to Visible Infrared Imaging Radiometer Suite (VIIRS) and Ozone Mapping and Profiler Suite (OMPS) data. We also now include dust layers as well as smoke. Other updates include improvements in retrieving the AOD of nonspherical dust from VIIRS, better determination of the aerosol layer height from CALIOP, and more realistic input aerosol profiles in the forward model for better accuracy.

Physician emigration from sub-Saharan Africa to the United States: analysis of the 2011 AMA physician masterfile.

PubMed

Tankwanchi, Akhenaten Benjamin Siankam; Ozden, Cağlar; Vermund, Sten H

2013-01-01

The large-scale emigration of physicians from sub-Saharan Africa (SSA) to high-income nations is a serious development concern. Our objective was to determine current emigration trends of SSA physicians found in the physician workforce of the United States. We analyzed physician data from the World Health Organization (WHO) Global Health Workforce Statistics along with graduation and residency data from the 2011 American Medical Association Physician Masterfile (AMA-PM) on physicians trained or born in SSA countries who currently practice in the US. We estimated emigration proportions, year of US entry, years of practice before emigration, and length of time in the US. According to the 2011 AMA-PM, 10,819 physicians were born or trained in 28 SSA countries. Sixty-eight percent (n = 7,370) were SSA-trained, 20% (n = 2,126) were US-trained, and 12% (n = 1,323) were trained outside both SSA and the US. We estimated active physicians (age ≤ 70 years) to represent 96% (n = 10,377) of the total. Migration trends among SSA-trained physicians increased from 2002 to 2011 for all but one principal source country; the exception was South Africa whose physician migration to the US decreased by 8% (-156). The increase in last-decade migration was >50% in Nigeria (+1,113) and Ghana (+243), >100% in Ethiopia (+274), and >200% (+244) in Sudan. Liberia was the most affected by migration to the US with 77% (n = 175) of its estimated physicians in the 2011 AMA-PM. On average, SSA-trained physicians have been in the US for 18 years. They practiced for 6.5 years before US entry, and nearly half emigrated during the implementation years (1984-1999) of the structural adjustment programs. Physician emigration from SSA to the US is increasing for most SSA source countries. Unless far-reaching policies are implemented by the US and SSA countries, the current emigration trends will persist, and the US will remain a leading destination for SSA physicians emigrating from the continent of greatest need. Please see later in the article for the Editors' Summary.

Physician Emigration from Sub-Saharan Africa to the United States: Analysis of the 2011 AMA Physician Masterfile

PubMed Central

Tankwanchi, Akhenaten Benjamin Siankam; Özden, Çağlar; Vermund, Sten H.

2013-01-01

Background The large-scale emigration of physicians from sub-Saharan Africa (SSA) to high-income nations is a serious development concern. Our objective was to determine current emigration trends of SSA physicians found in the physician workforce of the United States. Methods and Findings We analyzed physician data from the World Health Organization (WHO) Global Health Workforce Statistics along with graduation and residency data from the 2011 American Medical Association Physician Masterfile (AMA-PM) on physicians trained or born in SSA countries who currently practice in the US. We estimated emigration proportions, year of US entry, years of practice before emigration, and length of time in the US. According to the 2011 AMA-PM, 10,819 physicians were born or trained in 28 SSA countries. Sixty-eight percent (n = 7,370) were SSA-trained, 20% (n = 2,126) were US-trained, and 12% (n = 1,323) were trained outside both SSA and the US. We estimated active physicians (age ≤70 years) to represent 96% (n = 10,377) of the total. Migration trends among SSA-trained physicians increased from 2002 to 2011 for all but one principal source country; the exception was South Africa whose physician migration to the US decreased by 8% (−156). The increase in last-decade migration was >50% in Nigeria (+1,113) and Ghana (+243), >100% in Ethiopia (+274), and >200% (+244) in Sudan. Liberia was the most affected by migration to the US with 77% (n = 175) of its estimated physicians in the 2011 AMA-PM. On average, SSA-trained physicians have been in the US for 18 years. They practiced for 6.5 years before US entry, and nearly half emigrated during the implementation years (1984–1999) of the structural adjustment programs. Conclusion Physician emigration from SSA to the US is increasing for most SSA source countries. Unless far-reaching policies are implemented by the US and SSA countries, the current emigration trends will persist, and the US will remain a leading destination for SSA physicians emigrating from the continent of greatest need. Please see later in the article for the Editors' Summary PMID:24068894

Insight into Generation and Evolution of Sea-Salt Aerosols from Field Measurements in Diversified Marine and Coastal Atmospheres

PubMed Central

Feng, Limin; Shen, Hengqing; Zhu, Yujiao; Gao, Huiwang; Yao, Xiaohong

2017-01-01

This report focuses on studying generation and/or evolution of sea-salt aerosols (SSA) on basis of measurements in the Northwest Pacific Ocean (NWPO), the marginal seas of China, at sea-beach sites and a semi-urban coastal site in 2012–2015. From measurements in the NWPO, we obtained the smallest generation function of the super-micron SSA mass ([MSSA]) by the local wind comparing to those previously reported. Vessel-caused wave-breaking was found to greatly enhance generation of SSA and increase [MSSA], which was subject to non-natural generation of SSA. However, naturally enhanced generation of SSA was indeed observed in the marginal seas and at the sea-beach site. The two enhancement mechanisms may explain the difference among this and previous studies. Size distributions of super-micron SSA exhibited two modes, i.e., 1–2 μm mode and ~5 μm mode. The 1–2 μm mode of SSA was enhanced more and comparable to the ~5 μm mode under the wind speed >7 m/s. However, the smaller mode SSA was largely reduced from open oceans to sea-beach sites with reducing wind speed. The two super-micron modes were comparable again at a semi-urban coastal site, suggesting that the smaller super-micron mode SSA may play more important roles in atmospheres. PMID:28120906

Analysis and correction for measurement error of edge sensors caused by deformation of guide flexure applied in the Thirty Meter Telescope SSA.

PubMed

Cao, Haifeng; Zhang, Jingxu; Yang, Fei; An, Qichang; Zhao, Hongchao; Guo, Peng

2018-05-01

The Thirty Meter Telescope (TMT) project will design and build a 30-m-diameter telescope for research in astronomy in visible and infrared wavelengths. The primary mirror of TMT is made up of 492 hexagonal mirror segments under active control. The highly segmented primary mirror will utilize edge sensors to align and stabilize the relative piston, tip, and tilt degrees of segments. The support system assembly (SSA) of the segmented mirror utilizes a guide flexure to decouple the axial support and lateral support, while its deformation will cause measurement error of the edge sensor. We have analyzed the theoretical relationship between the segment movement and the measurement value of the edge sensor. Further, we have proposed an error correction method with a matrix. The correction process and the simulation results of the edge sensor will be described in this paper.

BOREAS RSS-8 BIOME-BGC SSA Simulation of Annual Water and Carbon Fluxes

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Kimball, John

2000-01-01

The BOREAS RSS-8 team performed research to evaluate the effect of seasonal weather and landcover heterogeneity on boreal forest regional water and carbon fluxes using a process-level ecosystem model, BIOME-BGC, coupled with remote sensing-derived parameter maps of key state variables. This data set contains derived maps of landcover type and crown and stem biomass as model inputs to determine annual evapotranspiration, gross primary production, autotrophic respiration, and net primary productivity within the BOREAS SSA-MSA, at a 30-m spatial resolution. Model runs were conducted over a 3-year period from 1994-1996; images are provided for each of those years. The data are stored in binary image format. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

GOCI Yonsei Aerosol Retrieval (YAER) algorithm and validation during DRAGON-NE Asia 2012 campaign

NASA Astrophysics Data System (ADS)

Choi, M.; Kim, J.; Lee, J.; Kim, M.; Park, Y. Je; Jeong, U.; Kim, W.; Holben, B.; Eck, T. F.; Lim, J. H.; Song, C. K.

2015-09-01

The Geostationary Ocean Color Imager (GOCI) onboard the Communication, Ocean, and Meteorology Satellites (COMS) is the first multi-channel ocean color imager in geostationary orbit. Hourly GOCI top-of-atmosphere radiance has been available for the retrieval of aerosol optical properties over East Asia since March 2011. This study presents improvements to the GOCI Yonsei Aerosol Retrieval (YAER) algorithm over ocean and land together with validation results during the DRAGON-NE Asia 2012 campaign. Optical properties of aerosol are retrieved from the GOCI YAER algorithm including aerosol optical depth (AOD) at 550 nm, fine-mode fraction (FMF) at 550 nm, single scattering albedo (SSA) at 440 nm, Angstrom exponent (AE) between 440 and 860 nm, and aerosol type from selected aerosol models in calculating AOD. Assumed aerosol models are compiled from global Aerosol Robotic Networks (AERONET) inversion data, and categorized according to AOD, FMF, and SSA. Nonsphericity is considered, and unified aerosol models are used over land and ocean. Different assumptions for surface reflectance are applied over ocean and land. Surface reflectance over the ocean varies with geometry and wind speed, while surface reflectance over land is obtained from the 1-3 % darkest pixels in a 6 km × 6 km area during 30 days. In the East China Sea and Yellow Sea, significant area is covered persistently by turbid waters, for which the land algorithm is used for aerosol retrieval. To detect turbid water pixels, TOA reflectance difference at 660 nm is used. GOCI YAER products are validated using other aerosol products from AERONET and the MODIS Collection 6 aerosol data from "Dark Target (DT)" and "Deep Blue (DB)" algorithms during the DRAGON-NE Asia 2012 campaign from March to May 2012. Comparison of AOD from GOCI and AERONET gives a Pearson correlation coefficient of 0.885 and a linear regression equation with GOCI AOD =1.086 × AERONET AOD - 0.041. GOCI and MODIS AODs are more highly correlated over ocean than land. Over land, especially, GOCI AOD shows better agreement with MODIS DB than MODIS DT because of the choice of surface reflectance assumptions. Other GOCI YAER products show lower correlation with AERONET than AOD, but are still qualitatively useful.

Atmospheric Aerosol Emissions Related to the Mediterranean Seawater Biogeochemistry

NASA Astrophysics Data System (ADS)

Sellegri, K.; Schwier, A.; Rose, C.; Gazeau, F. P. H.; Guieu, C.; D'anna, B.; Ebling, A. M.; Pey, J.; Marchand, N.; Charriere, B.; Sempéré, R.; Mas, S.

2016-02-01

Marine aerosols contribute significantly to the global aerosol load and consequently has an important impact on the Earth's climate. Different factors influence the way they are produced at the air/seawater interface. The sea state (whitecap coverage, temperature, etc. ) influence the size and concentration of primarily produced particles but also biogeochemical characteristics of the seawater influence both the physical and chemical primary fluxes to the atmosphere. An additional aerosol source of marine aerosol to the atmosphere is the formation of new particles by gaz-to-particle conversion, i.e. nucleation. How the seawater and surface microlayer biogeochemical compositions influences the aerosol emissions is still a large debate. In order to study marine emissions, one approach is to use semi-controlled environments such as mesocosms. Within the MedSea and SAM projects, we characterize the primary Sea Spray Aerosol (SSA) during mesocosms experiments performed during different seasons in the Mediteranean Sea. Mesocosms were either left unchanged as control or enriched by addition of nutriments in order to create different levels of phytoplanctonic activities. The mesocosms waters were daily analyzed for their chemical and biological composition (DOC, CDOM, TEP, Chl-a, virus, bacteria, phytoplankton and zooplankton concentrations). SSA production by bubble bursting was daily simulated in a dedicated set-up. The size segregated SSA number fluxes, cloud condensation nuclei (CCN) properties, and chemical composition were determined as a function of the seawater characteristics. We show that the SSA organic content was clearly correlated to the seawater Chl-a level, provided that the mesocosm was not enriched to create an artificial phytoplanctonic bloom. In our experiments, the enrichment of the seawater with natural surface microlayer did not impact the SSA organic content nor its CCN properties. At last, nucleation of secondary particles were observed to occur in the mesocosm headspace, without any connection to DMS emissions. The occurrence of nucleation of new particles in the open ocean atmosphere is still debated and these findings will be discussed in regard to observations performed in the ambient Mediterranean atmosphere during the MISTRAL/Charmex project.

Space Shuttle/TDRSS communication and tracking systems analysis

NASA Astrophysics Data System (ADS)

Lindsey, W. C.; Chie, C. M.; Cideciyan, R.; Dessouky, K.; Su, Y. T.; Tsang, C. S.

1986-04-01

In order to evaluate the technical and operational problem areas and provide a recommendation, the enhancements to the Tracking and Data Delay Satellite System (TDRSS) and Shuttle must be evaluated through simulation and analysis. These enhancement techniques must first be characterized, then modeled mathematically, and finally updated into LinCsim (analytical simulation package). The LinCsim package can then be used as an evaluation tool. Three areas of potential enhancements were identified: shuttle payload accommodations, TDRSS SSA and KSA services, and shuttle tracking system and navigation sensors. Recommendations for each area were discussed.

Space Shuttle/TDRSS communication and tracking systems analysis

NASA Technical Reports Server (NTRS)

Lindsey, W. C.; Chie, C. M.; Cideciyan, R.; Dessouky, K.; Su, Y. T.; Tsang, C. S.

1986-01-01

In order to evaluate the technical and operational problem areas and provide a recommendation, the enhancements to the Tracking and Data Delay Satellite System (TDRSS) and Shuttle must be evaluated through simulation and analysis. These enhancement techniques must first be characterized, then modeled mathematically, and finally updated into LinCsim (analytical simulation package). The LinCsim package can then be used as an evaluation tool. Three areas of potential enhancements were identified: shuttle payload accommodations, TDRSS SSA and KSA services, and shuttle tracking system and navigation sensors. Recommendations for each area were discussed.

Space Situational Awareness using Market Based Agents

NASA Astrophysics Data System (ADS)

Sullivan, C.; Pier, E.; Gregory, S.; Bush, M.

2012-09-01

Space surveillance for the DoD is not limited to the Space Surveillance Network (SSN). Other DoD-owned assets have some existing capabilities for tasking but have no systematic way to work collaboratively with the SSN. These are run by diverse organizations including the Services, other defense and intelligence agencies and national laboratories. Beyond these organizations, academic and commercial entities have systems that possess SSA capability. Most all of these assets have some level of connectivity, security, and potential autonomy. Exploiting them in a mutually beneficial structure could provide a more comprehensive, efficient and cost effective solution for SSA. The collection of all potential assets, providers and consumers of SSA data comprises a market which is functionally illiquid. The development of a dynamic marketplace for SSA data could enable would-be providers the opportunity to sell data to SSA consumers for monetary or incentive based compensation. A well-conceived market architecture could drive down SSA data costs through increased supply and improve efficiency through increased competition. Oceanit will investigate market and market agent architectures, protocols, standards, and incentives toward producing high-volume/low-cost SSA.

A Novel Method for Satellite Maneuver Prediction

NASA Astrophysics Data System (ADS)

Shabarekh, C.; Kent-Bryant, J.; Keselman, G.; Mitidis, A.

2016-09-01

A space operations tradecraft consisting of detect-track-characterize-catalog is insufficient for maintaining Space Situational Awareness (SSA) as space becomes increasingly congested and contested. In this paper, we apply analytical methodology from the Geospatial-Intelligence (GEOINT) community to a key challenge in SSA: predicting where and when a satellite may maneuver in the future. We developed a machine learning approach to probabilistically characterize Patterns of Life (PoL) for geosynchronous (GEO) satellites. PoL are repeatable, predictable behaviors that an object exhibits within a context and is driven by spatio-temporal, relational, environmental and physical constraints. An example of PoL are station-keeping maneuvers in GEO which become generally predictable as the satellite re-positions itself to account for orbital perturbations. In an earlier publication, we demonstrated the ability to probabilistically predict maneuvers of the Galaxy 15 (NORAD ID: 28884) satellite with high confidence eight days in advance of the actual maneuver. Additionally, we were able to detect deviations from expected PoL within hours of the predicted maneuver [6]. This was done with a custom unsupervised machine learning algorithm, the Interval Similarity Model (ISM), which learns repeating intervals of maneuver patterns from unlabeled historical observations and then predicts future maneuvers. In this paper, we introduce a supervised machine learning algorithm that works in conjunction with the ISM to produce a probabilistic distribution of when future maneuvers will occur. The supervised approach uses a Support Vector Machine (SVM) to process the orbit state whereas the ISM processes the temporal intervals between maneuvers and the physics-based characteristics of the maneuvers. This multiple model approach capitalizes on the mathematical strengths of each respective algorithm while incorporating multiple features and inputs. Initial findings indicate that the combined approach can predict 70% of maneuver times within 3 days of a true maneuver time and 22% of maneuver times within 24 hours of a maneuver. We have also been able to detect deviations from expected maneuver patterns up to a week in advance.

Improvement of Aerosol Optical Depth Retrieval from MODIS Spectral Reflectance over the Global Ocean Using New Aerosol Models Archived from AERONET Inversion Data and Tri-axial Ellipsoidal Dust Database

NASA Technical Reports Server (NTRS)

Lee, J.; Kim, J.; Yang, P.; Hsu, N. C.

2012-01-01

New over-ocean aerosol models are developed by integrating the inversion data from the Aerosol Robotic Network (AERONET) sun/sky radiometers with a database for the optical properties of tri-axial ellipsoid particles. The new aerosol models allow more accurate retrieval of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) in the case of high AOD (AOD greater than 0.3). The aerosol models are categorized by using the fine-mode fraction (FMF) at 550 nm and the singlescattering albedo (SSA) at 440 nm from the AERONET inversion data to include a variety of aerosol types found around the globe. For each aerosol model, the changes in the aerosol optical properties (AOPs) as functions of AOD are considered to better represent aerosol characteristics. Comparisons of AODs between AERONET and MODIS for the period from 2003 to 2010 show that the use of the new aerosol models enhances the AOD accuracy with a Pearson coefficient of 0.93 and a regression slope of 0.99 compared to 0.92 and 0.85 calculated using the MODIS Collection 5 data. Moreover, the percentage of data within an expected error of +/-(0.03 + 0.05xAOD) is increased from 62 percent to 64 percent for overall data and from 39 percent to 51 percent for AOD greater than 0.3. Errors in the retrieved AOD are further characterized with respect to the Angstrom exponent (AE), scattering angle, SSA, and air mass factor (AMF). Due to more realistic AOPs assumptions, the new algorithm generally reduces systematic errors in the retrieved AODs compared with the current operational algorithm. In particular, the underestimation of fine-dominated AOD and the scattering angle dependence of dust-dominated AOD are significantly mitigated as results of the new algorithm's improved treatment of aerosol size distribution and dust particle nonsphericity.

77 FR 51840 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... personal information from SSA records, or who register to participate in SSA's online business services, to... parties who are registering for SSA's online business services. Type of Request: Revision of an OMB...

Screening, management and surveillance for the sessile serrated adenomas/polyps.

PubMed

Fu, Xiangsheng; Qiu, Ye; Zhang, Yali

2014-01-01

The incidence and mortality rates from right-sided colorectal cancers (CRCs) have not decreased, compared with the significant reduction of CRCs in the left colon in recent years. It is likely that a significant proportion of right-sided CRCs evolve from undetected sessile serrated adenomas/polyps (SSA/Ps) in the primary colonoscopy. Increasing evidences suggest that SSA/Ps are high-risk lesions, with 15% of the SSA/P patients developing subsequent CRCs or adenomas with high-grade dysplasia. However, there are many issues in the screening, management and surveillance of SSA/Ps. Based on new evidences, this review addresses major issues in the diagnostic criteria for the serrated polyps of the colorectum, new endoscopic techniques (high-resolution magnifying endoscopy, narrow-band imaging, autofluorescence imaging, confocal laser endoscopy, and endocytoscopy) for the realtime identification of SSA/Ps, and the management of SSA/Ps by endoscopic mucosal resection, endoscopic sub-mucosal dissection or surgical resection in practice.

The Impact of Marine Enzymatic Activity on Sea Spray Aerosol Properties

NASA Astrophysics Data System (ADS)

Ryder, O. S.; Michaud, J. M.; Sauer, J. S.; Lee, C.; Förster, J. D.; Pöhlker, C.; Andreae, M. O.; Prather, K. A.

2016-12-01

The composition of sea spray aerosol (SSA) and the relationship between its organic fraction and biological ocean conditions is not well understood, resulting in considerable disagreement in the literature linking biological markers to SSA chemical composition. Recent work suggests that enzymatic activity in seawater may play a key role in dictating aerosol composition by changing the organic pool from which SSA is formed. Here we investigate the role of enzymatic activity on SSA spatial chemical composition, aerosol phase and morphological microstructure. In these experiments, SSA was generated using a novel mini-Marine Aerosol Reference Tank system. SSA collected onto substrates was generated from artificial salt water that had been doped with either 1) unsaturated triglycerides or 2) diatom cellular lysate, both followed by lipase. Results from analysis including morphological studies via atomic force microscopy, and chemical composition investigations both under dry and RH conditions via STXM-NEXAFS are presented.

Space Situational Awareness in the Joint Space Operations Center

NASA Astrophysics Data System (ADS)

Wasson, M.

2011-09-01

Flight safety of orbiting resident space objects is critical to our national interest and defense. United States Strategic Command has assigned the responsibility for Space Situational Awareness (SSA) to its Joint Functional Component Command - Space (JFCC SPACE) at Vandenberg Air Force Base. This paper will describe current SSA imperatives, new developments in SSA tools and developments in Defensive Operations. Current SSA processes are being examined to capture, and possibly improve, tasking of SSN sensors and "new" space-based sensors, "common" conjunction assessment methodology, and SSA sharing due to the growth seen over the last two years. The stand-up of a Defensive Ops Branch will highlight the need for advanced analysis and collaboration across space, weather, intelligence, and cyber specialties. New developments in SSA tools will be a description of computing hardware/software upgrades planned as well as the use of User-Defined Operating Pictures and visualization applications.

Intergalactic medium emission observations with the cosmic web imager. II. Discovery of extended, kinematically linked emission around SSA22 Lyα BLOB 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christopher Martin, D.; Chang, Daphne; Matuszewski, Matt

The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Lyαmore » blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Lyα emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Lyα emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 × 10{sup 11} M {sub ☉}, and the dark halo mass is at least 2 × 10{sup 12} M {sub ☉}. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas have significant and coaligned angular momentum, strengthening the case for their association.« less

WENESSA, Wide Eye-Narrow Eye Space Simulation fo Situational Awareness

NASA Astrophysics Data System (ADS)

Albarait, O.; Payne, D. M.; LeVan, P. D.; Luu, K. K.; Spillar, E.; Freiwald, W.; Hamada, K.; Houchard, J.

In an effort to achieve timelier indications of anomalous object behaviors in geosynchronous earth orbit, a Planning Capability Concept (PCC) for a “Wide Eye-Narrow Eye” (WE-NE) telescope network has been established. The PCC addresses the problem of providing continuous and operationally robust, layered and cost-effective, Space Situational Awareness (SSA) that is focused on monitoring deep space for anomalous behaviors. It does this by first detecting the anomalies with wide field of regard systems, and then providing reliable handovers for detailed observational follow-up by another optical asset. WENESSA will explore the added value of such a system to the existing Space Surveillance Network (SSN). The study will assess and quantify the degree to which the PCC completely fulfills, or improves or augments, these deep space knowledge deficiencies relative to current operational systems. In order to improve organic simulation capabilities, we will explore options for the federation of diverse community simulation approaches, while evaluating the efficiencies offered by a network of small and larger aperture, ground-based telescopes. Existing Space Modeling and Simulation (M&S) tools designed for evaluating WENESSA-like problems will be taken into consideration as we proceed in defining and developing the tools needed to perform this study, leading to the creation of a unified Space M&S environment for the rapid assessment of new capabilities. The primary goal of this effort is to perform a utility assessment of the WE-NE concept. The assessment will explore the mission utility of various WE-NE concepts in discovering deep space anomalies in concert with the SSN. The secondary goal is to generate an enduring modeling and simulation environment to explore the utility of future proposed concepts and supporting technologies. Ultimately, our validated simulation framework would support the inclusion of other ground- and space-based SSA assets through integrated analysis. Options will be explored using at least two competing simulation capabilities, but emphasis will be placed on reasoned analyses as supported by the simulations.

Integrative genetic risk prediction using non-parametric empirical Bayes classification.

PubMed

Zhao, Sihai Dave

2017-06-01

Genetic risk prediction is an important component of individualized medicine, but prediction accuracies remain low for many complex diseases. A fundamental limitation is the sample sizes of the studies on which the prediction algorithms are trained. One way to increase the effective sample size is to integrate information from previously existing studies. However, it can be difficult to find existing data that examine the target disease of interest, especially if that disease is rare or poorly studied. Furthermore, individual-level genotype data from these auxiliary studies are typically difficult to obtain. This article proposes a new approach to integrative genetic risk prediction of complex diseases with binary phenotypes. It accommodates possible heterogeneity in the genetic etiologies of the target and auxiliary diseases using a tuning parameter-free non-parametric empirical Bayes procedure, and can be trained using only auxiliary summary statistics. Simulation studies show that the proposed method can provide superior predictive accuracy relative to non-integrative as well as integrative classifiers. The method is applied to a recent study of pediatric autoimmune diseases, where it substantially reduces prediction error for certain target/auxiliary disease combinations. The proposed method is implemented in the R package ssa. © 2016, The International Biometric Society.

Impact of Atmospheric Blocking on South America in Austral Summer

NASA Astrophysics Data System (ADS)

Rodrigues, Regina; Woollings, Tim

2017-04-01

In this study, we investigate atmospheric blocking over east South America in austral summer for the period of 1979-2014. Our results show that blocking over this area is a consequence of propagating Rossby waves that grow to large amplitudes and eventually break anticyclonically over subtropical South America (SSA). The SSA blocking can prevent the establishment of the South Atlantic Convergence Zone (SACZ). As such, years with more blocking days coincide with years with fewer SACZ days and reduced precipitation. Convection mainly over the Indian Ocean associated with Madden-Julian Oscillation (MJO) phases 1 and 2 can trigger the wave train that leads to SSA blocking whereas convection over the western/central Pacific associated with phases 6 and 7 is more likely to lead to SACZ events. We find that MJO is a key source of long-term variability in SSA blocking frequency. The wave packets associated with SSA blocking and SACZ episodes differ not only in their origin but also in their phase and refraction pattern. The tropopause-based methodology used here is proven to reliably identify events that lead to extremes of surface temperature and precipitation over SSA. Up to 80% of warm surface air temperature extremes occur simultaneously with SSA blocking events. They are also responsible for the warming of western South Atlantic. The frequency of SSA blocking days is highly anti-correlated with the rainfall over southeast Brazil. The worst droughts in this area, during the summers of 1984, 2001 and 2014, are linked to record high numbers of SSA blocking days. The persistence of these events is also important in generating the extreme impacts.

Involvement of signal peptidase I in Streptococcus sanguinis biofilm formation

PubMed Central

Ge, Xiuchun; Stone, Victoria; Zhu, Bin; Kitten, Todd

2017-01-01

Biofilm accounts for 65–80 % of microbial infections in humans. Considerable evidence links biofilm formation by oral microbiota to oral disease and consequently systemic infections. Streptococcus sanguinis, a Gram-positive bacterium, is one of the most abundant species of the oral microbiota and it contributes to biofilm development in the oral cavity. Due to its altered biofilm formation, we investigated a biofilm mutant, ΔSSA_0351, that is deficient in type I signal peptidase (SPase) in this study. Although the growth curve of the ΔSSA_0351 mutant showed no significant difference from that of the wild-type strain SK36, biofilm assays using both microtitre plate assay and confocal laser scanning microscopy (CLSM) confirmed a sharp reduction in biofilm formation in the mutant compared to the wild-type strain and the paralogous mutant ΔSSA_0849. Scanning electron microscopy (SEM) revealed remarkable differences in the cell surface morphologies and chain length of the ΔSSA_0351 mutant compared with those of the wild-type strain. Transcriptomic and proteomic assays using RNA sequencing and mass spectrometry, respectively, were conducted on the ΔSSA_0351 mutant to evaluate the functional impact of SPase on biofilm formation. Subsequently, bioinformatics analysis revealed a number of proteins that were differentially regulated in the ΔSSA_0351 mutant, narrowing down the list of SPase substrates involved in biofilm formation to lactate dehydrogenase (SSA_1221) and a short-chain dehydrogenase (SSA_0291). With further experimentation, this list defined the link between SSA_0351-encoded SPase, cell wall biosynthesis and biofilm formation. PMID:28869408

Genome-wide association study (GWAS) for growth rate and age at sexual maturation in Atlantic salmon (Salmo salar).

PubMed

Gutierrez, Alejandro P; Yáñez, José M; Fukui, Steve; Swift, Bruce; Davidson, William S

2015-01-01

Early sexual maturation is considered a serious drawback for Atlantic salmon aquaculture as it retards growth, increases production times and affects flesh quality. Although both growth and sexual maturation are thought to be complex processes controlled by several genetic and environmental factors, selection for these traits has been continuously accomplished since the beginning of Atlantic salmon selective breeding programs. In this genome-wide association study (GWAS) we used a 6.5K single-nucleotide polymorphism (SNP) array to genotype ∼ 480 individuals from the Cermaq Canada broodstock program and search for SNPs associated with growth and age at sexual maturation. Using a mixed model approach we identified markers showing a significant association with growth, grilsing (early sexual maturation) and late sexual maturation. The most significant associations were found for grilsing, with markers located in Ssa10, Ssa02, Ssa13, Ssa25 and Ssa12, and for late maturation with markers located in Ssa28, Ssa01 and Ssa21. A lower level of association was detected with growth on Ssa13. Candidate genes, which were linked to these genetic markers, were identified and some of them show a direct relationship with developmental processes, especially for those in association with sexual maturation. However, the relatively low power to detect genetic markers associated with growth (days to 5 kg) in this GWAS indicates the need to use a higher density SNP array in order to overcome the low levels of linkage disequilibrium observed in Atlantic salmon before the information can be incorporated into a selective breeding program.

Serrated polyps of the colon and rectum: Endoscopic features including image enhanced endoscopy

PubMed Central

Saito, Shoichi; Tajiri, Hisao; Ikegami, Masahiro

2015-01-01

In this review, I outline the characteristic endoscopic findings of serrated lesions of the colorectum based on image enhanced endoscopy (IEE). Histopathologically, lesions with serrated structures are typically classified into the following three types based: hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenoma/polyps (SSA/Ps). Both HP and SSA/P often present as dark-green colors on auto fluorescence imaging (AFI) colonoscopy that are similar to the normal surrounding mucosa. In contrast, TSAs often have elevated shapes and present as magenta colors that are similar to the tubular adenomas. The superficial type of TSA also includes many lesions that present as magenta colors. When SSA/Ps are associated with cytological dysplasia, many lesions present with magenta colors, whereas lesions that are not associated with cytological dysplasia present with dark-green colors. When observed via narrow band imaging (NBI), many SSA/P include lesions with strong mucous adhesions. Because these lesions are observed with reddish mucous adhesions, we refer to them as “red cap sign” and place such signs among the typical findings of SSA/P. Because the dilatation of the pit in SSA/P is observed as a round/oval black dot on magnified observations, we refer to this finding as II-dilatation pit (II-D pit) and also positioned it as a characteristic finding of SSA/P. In contrast, dilatations of the capillary vessels surrounding the glands, such as those that occur in tubular adenoma, are not considered to be useful for differentiating HPs from SSA/Ps. However, in cases in which SSA/P is associated with cytological dysplasia, the dilatation of capillary vessels is observed in the same area. When submucosal layer invasion occurs in the same area, the blood flow presents with irregularities that are similar to those of common colorectal cancer at an early stage and disappears as the invasion proceeds deeply. The surface pattern of invasive cancer that is observed at the tumor surface is also likely to disappear. Based on the above results, we considered that the differentiations between HP and TSA, between TSA and SSA/P, and between HP and SSA/P might become easier due to the concomitant use of white light observation and IEE. We also concluded that AFI and NBI can be useful modalities for SSA/P lesions associated with cytological dysplasia. PMID:26240687

A New Trend-Following Indicator: Using SSA to Design Trading Rules

NASA Astrophysics Data System (ADS)

Leles, Michel Carlo Rodrigues; Mozelli, Leonardo Amaral; Guimarães, Homero Nogueira

Singular Spectrum Analysis (SSA) is a non-parametric approach that can be used to decompose a time-series as trends, oscillations and noise. Trend-following strategies rely on the principle that financial markets move in trends for an extended period of time. Moving Averages (MAs) are the standard indicator to design such strategies. In this study, SSA is used as an alternative method to enhance trend resolution in comparison with the traditional MA. New trading rules using SSA as indicator are proposed. This paper shows that for the Down Jones Industrial Average (DJIA) and Shangai Securities Composite Index (SSCI) time-series the SSA trading rules provided, in general, better results in comparison to MA trading rules.

ESA situational awareness of space weather

NASA Astrophysics Data System (ADS)

Luntama, Juha-Pekka; Glover, Alexi; Keil, Ralf; Kraft, Stefan; Lupi, Adriano

2016-07-01

ESA SSA Period 2 started at the beginning of 2013 and will last until the end of 2016. For the Space Weather Segment, transition to Period 2 introduced an increasing amount of development of new space weather service capability in addition to networking existing European assets. This transition was started already towards the end of SSA Period 1 with the initiation of the SSA Space Weather Segment architecture definition studies and activities enhancing existing space weather assets. The objective of Period 2 has been to initiate SWE space segment developments in the form of hosted payload missions and further expand the federated service network. A strong focus has been placed on demonstration and testing of European capabilities in the range of SWE service domains with a view to establishing core products which can form the basis of SWE service provision during SSA Period 3. This focus has been particularly addressed in the SSA Expert Service Centre (ESC) Definition and Development activity that was started in September 2015. This presentation will cover the current status of the SSA SWE Segment and the achievements during SSA Programme Periods 1 and 2. Particular attention is given to the federated approach that allow building the end user services on the best European expertise. The presentation will also outline the plans for the Space Weather capability development in the framework of the ESA SSA Programme in 2017-2020.

Periodically Launched, Dedicated CubeSats/SmallSats for Space Situational Awareness Through NASA Communications Networks

NASA Astrophysics Data System (ADS)

Stromberg, E. M.; Shaw, H.; Estabrook, P.; Neilsen, T. L.; Gunther, J.; Swenson, C.; Fish, C. S.; Schaire, S. H.

2014-12-01

Space Situational Awareness (SSA) is an area where spaceflight activities and missions can directly influence the quality of life on earth. The combination of space weather, near earth orbiting objects, atmospheric conditions at the space boundary, and other phenomena can have significant short-term and long-term implications for the inhabitants of this planet. The importance of SSA has led to increased activity in this area from both space and ground based platforms. The emerging capability of CubeSats and SmallSats provides an opportunity for these low-cost, versatile platforms to augment the SSA infrastructure. The CubeSats and SmallSats can be launched opportunistically with shorter lead times than larger missions. They can be organized both as constellations or individual sensor elements. Combining CubeSats and SmallSats with the existing NASA communications networks (TDRS Space Network, Deep Space Network and the Near Earth Network) provide a backbone structure for SSA which can be tied to a SSA portal for data distribution and management. In this poster we will describe the instruments and sensors needed for CubeSat and SmallSat SSA missions. We will describe the architecture and concept of operations for a set of opportunistic, periodically launched, SSA CubeSats and SmallSats. We will also describe the integrated communications infrastructure to support end-to-end data delivery and management to a SSA portal.

Bringing the ocean into the laboratory to probe the chemical complexity of sea spray aerosol

PubMed Central

Prather, Kimberly A.; Bertram, Timothy H.; Grassian, Vicki H.; Deane, Grant B.; Stokes, M. Dale; DeMott, Paul J.; Aluwihare, Lihini I.; Palenik, Brian P.; Azam, Farooq; Seinfeld, John H.; Moffet, Ryan C.; Molina, Mario J.; Cappa, Christopher D.; Geiger, Franz M.; Roberts, Gregory C.; Russell, Lynn M.; Ault, Andrew P.; Baltrusaitis, Jonas; Collins, Douglas B.; Corrigan, Craig E.; Cuadra-Rodriguez, Luis A.; Ebben, Carlena J.; Forestieri, Sara D.; Guasco, Timothy L.; Hersey, Scott P.; Kim, Michelle J.; Lambert, William F.; Modini, Robin L.; Mui, Wilton; Pedler, Byron E.; Ruppel, Matthew J.; Ryder, Olivia S.; Schoepp, Nathan G.; Sullivan, Ryan C.; Zhao, Defeng

2013-01-01

The production, size, and chemical composition of sea spray aerosol (SSA) particles strongly depend on seawater chemistry, which is controlled by physical, chemical, and biological processes. Despite decades of studies in marine environments, a direct relationship has yet to be established between ocean biology and the physicochemical properties of SSA. The ability to establish such relationships is hindered by the fact that SSA measurements are typically dominated by overwhelming background aerosol concentrations even in remote marine environments. Herein, we describe a newly developed approach for reproducing the chemical complexity of SSA in a laboratory setting, comprising a unique ocean-atmosphere facility equipped with actual breaking waves. A mesocosm experiment was performed in natural seawater, using controlled phytoplankton and heterotrophic bacteria concentrations, which showed SSA size and chemical mixing state are acutely sensitive to the aerosol production mechanism, as well as to the type of biological species present. The largest reduction in the hygroscopicity of SSA occurred as heterotrophic bacteria concentrations increased, whereas phytoplankton and chlorophyll-a concentrations decreased, directly corresponding to a change in mixing state in the smallest (60–180 nm) size range. Using this newly developed approach to generate realistic SSA, systematic studies can now be performed to advance our fundamental understanding of the impact of ocean biology on SSA chemical mixing state, heterogeneous reactivity, and the resulting climate-relevant properties. PMID:23620519

Adsorption of lead on multi-walled carbon nanotubes with different outer diameters and oxygen contents: kinetics, isotherms and thermodynamics.

PubMed

Yu, Fei; Wu, Yanqing; Ma, Jie; Zhang, Chi

2013-01-01

The effects of different outer diameters and surface oxygen contents on the adsorption of heavy metals onto six types of multi-walled carbon nanotubes (MWCNTs) were investigated in an aqueous solution and lead was chosen as a model metal ion. The results indicated that the percentage removal and adsorption capacity of lead remarkably increased with decreasing outer diameter due to larger specific surface area (SSA). The SSA-normalized maximum adsorption capacity (qmSSA) and SSA-normalized adsorption coefficient (Kd/SSA) were strongly positively correlated with surface oxygen content, implying that lead adsorption onto MWCNTs significantly increases with the rise of oxygen content and decreases with decreasing SSA. The calculated thermodynamic parameters indicated that adsorption of lead on MWCNTs was endothermic and spontaneous. When the oxygen content of MWCNTs increased from 2.0% to 5.9%, the standard free energy (deltaG0) became more negative, which implied that the oxygenated functional groups increased the adsorption affinity of MWCNTs for lead. Through calculation of enthalpy (deltaH0), deltaG0 and free energy of adsorption (Ea), lead adsorption onto MWCNTs was recognized as a chemisorption process. The chemical interaction between lead and the phenolic groups of MWCNTs could be one of the main adsorption mechanisms due to highly positive correlations between the phenolic groups and Kd/SSA or qm/SSA.

ANALYSIS OF STANDARD MULTI-PORT VS. SINGLE SITE ACCESS FOR LAPAROSCOPIC SKILLS TRAINING

PubMed Central

Cox, Daniel R; Zeng, Wenjing; Frisella, Margaret M; Brunt, L. Michael

2015-01-01

Introduction Single site access (SSA) laparoscopy is more challenging to perform than multi-port(MP) laparoscopy. We examined MP versus SSA skills training on laparoscopic performance in surgically naive individuals. Methods Forty end-of-1st year medical students were randomized into two groups. Both were trained on 4 basic laparoscopic drills (peg, rope, bean drop, pattern cutting) using a standard MP setup (Group 1) or SSA approach (Group 2). Time to proficiency and number of repetitions (reps) were recorded. Each group then crossed over to the alternate approach where the sequence was repeated. Data are mean ± SD and statistical analysis was with two-tailed, unpaired t-test. Results Total times to proficiency for the SSA and MP approaches was not significantly different between groups (Group 1 M-P 234.0 ± 114.9 min vs Group 2 SSA 216.4 ± 106.5 min, p=0.67). The MP-trained group took less time to reach proficiency on the standard MP setup than the SSA group on the SSA approach (119.1 ± 69.7 min vs 178.0 ± 93.4 min, p=0.058) with significantly fewer repetitions (77.6 ± 42.6 vs. 118.8 ± 54.3, p=0.027). The SSA-trained group took significantly less time to reach proficiency on the MP setup than the standard MP-trained group (38.4 ± 29.4 min vs. 119.1 ± 69.7 min; p=0.0013) requiring only a mean of 26.9 total repetitions. When the standard MP group crossed over to the SSA setup, they took significantly less time to reach proficiency with the SSA approach than the SSA-trained group (114.8 ± 50.5 min vs. 178.0 ± 93.4 min, p=0.026) but with more total repetitions than with the M-P approach (86.2 ± 35.2 vs 77.6 ± 42.6, p= NS). Conclusions Laparoscopic single site access skills training results in longer times and more repetitions to achieve proficiency than multi-port training, but the skills acquired transfer well to the multi-port approach. PMID:20872019

Monitoring Sub-Saharan African Physician Migration and Recruitment Post-Adoption of the WHO Code of Practice: Temporal and Geographic Patterns in the United States

PubMed Central

Tankwanchi, Akhenaten Benjamin Siankam; Vermund, Sten H.; Perkins, Douglas D.

2015-01-01

Data monitoring is a key recommendation of the WHO Global Code of Practice on the International Recruitment of Health Personnel, a global framework adopted in May 2010 to address health workforce retention in resource-limited countries and the ethics of international migration. Using data on African-born and African-educated physicians in the 2013 American Medical Association Physician Masterfile (AMA Masterfile), we monitored Sub-Saharan African (SSA) physician recruitment into the physician workforce of the United States (US) post-adoption of the WHO Code of Practice. From the observed data, we projected to 2015 with linear regression, and we mapped migrant physicians’ locations using GPS Visualizer and ArcGIS. The 2013 AMA Masterfile identified 11,787 active SSA-origin physicians, representing barely 1.3% (11,787/940,456) of the 2013 US physician workforce, but exceeding the total number of physicians reported by WHO in 34 SSA countries (N = 11,519). We estimated that 15.7% (1,849/11,787) entered the US physician workforce after the Code of Practice was adopted. Compared to pre-Code estimates from 2002 (N = 7,830) and 2010 (N = 9,938), the annual admission rate of SSA émigrés into the US physician workforce is increasing. This increase is due in large part to the growing number of SSA-born physicians attending medical schools outside SSA, representing a trend towards younger migrants. Projection estimates suggest that there will be 12,846 SSA migrant physicians in the US physician workforce in 2015, and over 2,900 of them will be post-Code recruits. Most SSA migrant physicians are locating to large urban US areas where physician densities are already the highest. The Code of Practice has not slowed the SSA-to-US physician migration. To stem the physician “brain drain”, it is essential to incentivize professional practice in SSA and diminish the appeal of US migration with bolder interventions targeting primarily early-career (age ≤ 35) SSA physicians. PMID:25875010

76 FR 59180 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-23

... criteria. Respondents complete Form SSA-1026-REDE under the following circumstances: (1) When individuals...,420 SSA-1026-OCR-SM-REDE 225,000 1 18 67,500 Total 236,400 70,920 II. SSA submitted the information...

Quantification of dimethyl sulfide (DMS) production in the sea anemone Aiptasia sp. to simulate the sea-to-air flux from coral reefs

NASA Astrophysics Data System (ADS)

Franchini, Filippo; Steinke, Michael

2017-12-01

The production of dimethyl sulfide (DMS) is poorly quantified in tropical reef environments but forms an essential process that couples marine and terrestrial sulfur cycles and affects climate. Here we quantified net aqueous DMS production and the concentration of its cellular precursor dimethylsulfoniopropionate (DMSP) in the sea anemone Aiptasia sp., a model organism to study coral-related processes. Bleached anemones did not show net DMS production whereas symbiotic anemones produced DMS concentrations (mean ± standard error) of 160.7 ± 44.22 nmol g-1 dry weight (DW) after 48 h incubation. Symbiotic and bleached individuals showed DMSP concentrations of 32.7 ± 6.00 and 0.6 ± 0.19 µmol g-1 DW, respectively. We applied these findings to a Monte Carlo simulation to demonstrate that net aqueous DMS production accounts for only 20 % of gross aqueous DMS production. Monte Carlo-based estimations of sea-to-air fluxes of gaseous DMS showed that reefs may release 0.1 to 26.3 µmol DMS m-2 coral surface area (CSA) d-1 into the atmosphere with 40 % probability for rates between 0.5 and 1.5 µmol m-2 CSA d-1. These predictions were in agreement with directly quantified fluxes in previous studies. Conversion to a flux normalised to sea surface area (SSA) (range 0.1 to 17.4, with the highest probability for 0.3 to 1.0 µmol DMS m-2 SSA d-1) suggests that coral reefs emit gaseous DMS at lower rates than the average global oceanic DMS flux of 4.6 µmol m-2 SSA d-1 (19.6 Tg sulfur per year). The large difference between simulated gross and quantified net aqueous DMS production in corals suggests that the current and future potential for its production in tropical reefs is critically governed by DMS consumption processes. Hence, more research is required to assess the sensitivity of DMS-consumption pathways to ongoing environmental change in order to address the impact of predicted degradation of coral reefs on DMS production in tropical coastal ecosystems and its impact on future atmospheric DMS concentrations and climate.

Suppressing effect of saikosaponin A, an active ingredient of Bupleurum falcatum, on chocolate self-administration and reinstatement of chocolate seeking in rats.

PubMed

Lorrai, Irene; Maccioni, Paola; Carai, Mauro A M; Capra, Alessandro; Castelli, M Paola; Riva, Antonella; Morazzoni, Paolo; Gessa, Gian Luigi; Colombo, Giancarlo

2017-01-18

Recent lines of experimental evidence have indicated that saikosaponin A (SSA) - a bioactive ingredient of the medicinal plant, Bupleurum falcatum L. - suppressed alcohol, morphine, and cocaine self-administration in rats. The present paper was designed to assess whether the protective properties of SSA on addiction-related behaviors generalize to a hyperpalatable food such as a chocolate-flavored beverage (CFB). To this end, rats were initially trained to lever-respond for CFB [5% (w/v) Nesquik ® powder in water] under fixed ratio (FR) 10 (FR10) schedule of reinforcement. Once lever-responding reached stable levels, rats were treated acutely with two different dose ranges of SSA (0, 0.25, 0.5, and 1mg/kg; 0, 1, 2.5, and 5mg/kg; i.p.) and exposed to the FR10 and progressive ratio (PR) schedules of reinforcement in four independent experiments. The effect of acutely administered SSA (0, 0.25, 0.5, and 1mg/kg; i.p.) on cue-induced reinstatement of seeking behavior for CFB was also assessed. Under the FR and PR schedules of reinforcement, treatment with SSA diminished lever-responding for CFB, amount of self-administered CFB, and breakpoint for CFB. All variables were virtually completely suppressed after treatment with 5mg/kg SSA. Treatment with SSA also suppressed reinstatement of CFB-seeking behavior. No dose of SSA altered rat motor-performance, evaluated exposing all rats to an inverted screen test immediately after the self-administration session. These results demonstrate that acute treatment with SSA potently suppressed several addictive-like behaviors motivated by highly hedonic nourishment. These data extend to a highly rewarding natural stimulus the anti-addictive properties of SSA recently disclosed in rats self-administering alcohol, morphine, and cocaine. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Cytosolic Hsp70 and co-chaperones constitute a novel system for tRNA import into the nucleus

PubMed Central

Takano, Akira; Kajita, Takuya; Mochizuki, Makoto; Endo, Toshiya; Yoshihisa, Tohru

2015-01-01

tRNAs are unique among various RNAs in that they shuttle between the nucleus and the cytoplasm, and their localization is regulated by nutrient conditions. Although nuclear export of tRNAs has been well documented, the import machinery is poorly understood. Here, we identified Ssa2p, a major cytoplasmic Hsp70 in Saccharomyces cerevisiae, as a tRNA-binding protein whose deletion compromises nuclear accumulation of tRNAs upon nutrient starvation. Ssa2p recognizes several structural features of tRNAs through its nucleotide-binding domain, but prefers loosely-folded tRNAs, suggesting that Ssa2p has a chaperone-like activity for RNAs. Ssa2p also binds Nup116, one of the yeast nucleoporins. Sis1p and Ydj1p, cytoplasmic co-chaperones for Ssa proteins, were also found to contribute to the tRNA import. These results unveil a novel function of the Ssa2p system as a tRNA carrier for nuclear import by a novel mode of substrate recognition. Such Ssa2p-mediated tRNA import likely contributes to quality control of cytosolic tRNAs. DOI: http://dx.doi.org/10.7554/eLife.04659.001 PMID:25853343

Subspace techniques to remove artifacts from EEG: a quantitative analysis.

PubMed

Teixeira, A R; Tome, A M; Lang, E W; Martins da Silva, A

2008-01-01

In this work we discuss and apply projective subspace techniques to both multichannel as well as single channel recordings. The single-channel approach is based on singular spectrum analysis(SSA) and the multichannel approach uses the extended infomax algorithm which is implemented in the opensource toolbox EEGLAB. Both approaches will be evaluated using artificial mixtures of a set of selected EEG signals. The latter were selected visually to contain as the dominant activity one of the characteristic bands of an electroencephalogram (EEG). The evaluation is performed both in the time and frequency domain by using correlation coefficients and coherence function, respectively.

Optical Payload for the STARE Mission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simms, L; Riot, V; De Vries, W

2011-03-13

Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) is a nano-sat based mission designed to better determine the trajectory of satellites and space debris in orbit around earth. In this paper, we give a brief overview of the mission and its place in the larger context of Space Situational Awareness (SSA). We then describe the details of the central optical payload, touching on the optical design and characterization of the on-board image sensor used in our Cubesat based prototype. Finally, we discuss the on-board star and satellite track detection algorithm central to the success of the mission.

The Joint Space Operations Center Mission System and the Advanced Research, Collaboration, and Application Development Environment Status Update 2016

NASA Astrophysics Data System (ADS)

Murray-Krezan, Jeremy; Howard, Samantha; Sabol, Chris; Kim, Richard; Echeverry, Juan

2016-05-01

The Joint Space Operations Center (JSpOC) Mission System (JMS) is a service-oriented architecture (SOA) infrastructure with increased process automation and improved tools to enhance Space Situational Awareness (SSA) performed at the US-led JSpOC. The Advanced Research, Collaboration, and Application Development Environment (ARCADE) is a test-bed maintained and operated by the Air Force to (1) serve as a centralized test-bed for all research and development activities related to JMS applications, including algorithm development, data source exposure, service orchestration, and software services, and provide developers reciprocal access to relevant tools and data to accelerate technology development, (2) allow the JMS program to communicate user capability priorities and requirements to developers, (3) provide the JMS program with access to state-of-the-art research, development, and computing capabilities, and (4) support JMS Program Office-led market research efforts by identifying outstanding performers that are available to shepherd into the formal transition process. In this paper we will share with the international remote sensing community some of the recent JMS and ARCADE developments that may contribute to greater SSA at the JSpOC in the future, and share technical areas still in great need.

78 FR 45283 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-26

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection...: Desk Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA) Social...

78 FR 67434 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-12

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection... Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA) Social Security...

77 FR 29441 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-17

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection... Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA), Social Security...

78 FR 21181 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection... Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA) Social Security...

77 FR 6853 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-09

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection... Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA), Social Security...

78 FR 9102 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-07

... SOCIAL SECURITY ADMINISTRATION Agency Information Collection Activities: Proposed Request and Comment Request The Social Security Administration (SSA) publishes a list of information collection... Officer for SSA, Fax: 202-395-6974, Email address: [email protected] . (SSA) Social Security...

Model-Atmosphere Spectra of Central Stars of Planetary Nebulae - Access via the Virtual Observatory Service TheoSSA

NASA Astrophysics Data System (ADS)

Rauch, T.; Reindl, N.

2014-04-01

In the framework of the Virtual Observatory (VO), the German Astrophysical Virtual Observatory GAVO project provides easy access to theoretical spectral energy distributions (SEDs) within the registered GAVO service TheoSSA (http://dc.g-vo.org/theossa). TheoSSA is based on the well established Tübingen NLTE Model-Atmosphere Package (TMAP) for hot, compact stars. This includes central stars of planetary nebulae. We show examples of TheoSSA in operation.

Improving Assessment of Work Related Mental Health Function Using the Work Disability Functional Assessment Battery (WD-FAB).

PubMed

Marfeo, Elizabeth E; Ni, Pengsheng; McDonough, Christine; Peterik, Kara; Marino, Molly; Meterko, Mark; Rasch, Elizabeth K; Chan, Leighton; Brandt, Diane; Jette, Alan M

2018-03-01

Purpose To improve the mental health component of the Work Disability Functional Assessment Battery (WD-FAB), developed for the US Social Security Administration's (SSA) disability determination process. Specifically our goal was to expand the WD-FAB scales of mood & emotions, resilience, social interactions, and behavioral control to improve the depth and breadth of the current scales and expand the content coverage to include aspects of cognition & communication function. Methods Data were collected from a random, stratified sample of 1695 claimants applying for the SSA work disability benefits, and a general population sample of 2025 working age adults. 169 new items were developed to replenish the WD-FAB scales and analyzed using factor analysis and item response theory (IRT) analysis to construct unidimensional scales. We conducted computer adaptive test (CAT) simulations to examine the psychometric properties of the WD-FAB. Results Analyses supported the inclusion of four mental health subdomains: Cognition & Communication (68 items), Self-Regulation (34 items), Resilience & Sociability (29 items) and Mood & Emotions (34 items). All scales yielded acceptable psychometric properties. Conclusions IRT methods were effective in expanding the WD-FAB to assess mental health function. The WD-FAB has the potential to enhance work disability assessment both within the context of the SSA disability programs as well as other clinical and vocational rehabilitation settings.

Real-time Flare Detection in Ground-Based Hα Imaging at Kanzelhöhe Observatory

NASA Astrophysics Data System (ADS)

Pötzi, W.; Veronig, A. M.; Riegler, G.; Amerstorfer, U.; Pock, T.; Temmer, M.; Polanec, W.; Baumgartner, D. J.

2015-03-01

Kanzelhöhe Observatory (KSO) regularly performs high-cadence full-disk imaging of the solar chromosphere in the Hα and Ca ii K spectral lines as well as in the solar photosphere in white light. In the frame of ESA's (European Space Agency) Space Situational Awareness (SSA) program, a new system for real-time Hα data provision and automatic flare detection was developed at KSO. The data and events detected are published in near real-time at ESA's SSA Space Weather portal (http://swe.ssa.esa.int/web/guest/kso-federated). In this article, we describe the Hα instrument, the image-recognition algorithms we developed, and the implementation into the KSO Hα observing system. We also present the evaluation results of the real-time data provision and flare detection for a period of five months. The Hα data provision worked in 99.96 % of the images, with a mean time lag of four seconds between image recording and online provision. Within the given criteria for the automatic image-recognition system (at least three Hα images are needed for a positive detection), all flares with an area ≥ 50 micro-hemispheres that were located within 60° of the solar center and occurred during the KSO observing times were detected, a number of 87 events in total. The automatically determined flare importance and brightness classes were correct in ˜ 85 %. The mean flare positions in heliographic longitude and latitude were correct to within ˜ 1°. The median of the absolute differences for the flare start and peak times from the automatic detections in comparison with the official NOAA (and KSO) visual flare reports were 3 min (1 min).

Concordance and Discordance of Self-Rated and Researcher-Measured Successful Aging: Subtypes and Associated Factors.

PubMed

Gu, Danan; Feng, Qiushi; Sautter, Jessica M; Yang, Fang; Ma, Lei; Zhen, Zhihong

2017-03-01

To investigate subtypes of successful aging (SA) based on concordance and discordance between self-rated and researcher-defined measures and their associations with demographic, psychosocial, and life satisfaction factors. We used multinomial logistic regression models to analyze 2013 cross-sectional survey data from 1,962 persons aged 65 and older in Shanghai that measured self-rated successful aging (SSA) with a single global assessment and researcher-defined successful aging (RSA) with a cumulative deficit index reflecting physical, physiological, cognitive, psychological, and social engagement domains. We generated four subtypes based on these two dichotomous variables: nonsuccessful aging (non-SA; meeting neither the criterion of RSA nor the criterion of SSA), RSA-only (meeting the criterion of RSA-only but not the criterion of SSA), SSA-only (meeting the criterion of SSA-only but not the criterion of RSA), and both-successful aging (both-SA; meeting both criteria of RSA and SSA). In the sample, 32% were nonsuccessful agers, 7% RSA-only, 34% SSA-only, and 27% successful agers. Female gender and older age were associated with lower likelihood of RSA-only and both-SA relative to non-SA, but with greater likelihood of SSA-only. Good socioeconomic conditions and social networks were associated with greater likelihood of SSA-only and both-SA relative to non-SA or RSA-only. Satisfaction with life domains was robustly and positively associated with good successful aging outcomes. Researcher-defined successful aging and self-rated successful aging are different measures with distinct social correlates. Subtypes of concordance and discordance provide a more holistic biopsychosocial conceptualization of successful aging. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Neural Representation of Subjective Sexual Arousal in Men and Women.

PubMed

Parada, Mayte; Gérard, Marina; Larcher, Kevin; Dagher, Alain; Binik, Yitzchak M

2016-10-01

Studies investigating brain indices of sexual arousal have begun to elucidate the brain's role in processing subjective arousal; however, most research has focused on men, used discrete ratings of subjective arousal, and used stimuli too short to induce significant arousal in women. To examine brain regions modulated by changes in subjective sexual arousal (SSA) rating intensity in men and women. Two groups (20 men, 20 women) viewed movie clips (erotic or humorous) while continuously evaluating changes in their SSA using a Likert-like scale (0 = not aroused, 10 = most aroused) and answering discrete questions about liking the movies and wanting sexual stimulation. Brain activity was measured using functional magnetic resonance imaging. Blood oxygen level-dependent responses and continuous and discrete measurements of sexual arousal. Erotic movies induced significant SSA in men and women. No sex difference in mean SSA was found in response to the erotic movies on continuous or discrete measurements. Several brain regions were correlated with changes in SSA. Parametric modulation with rating intensity showed a specific group of regions within the parietal lobe that showed significant differences in activity among low, medium, and high SSA. Multiple regions were concordant with changes in SSA; however, a subset of regions in men and women was modulated by SSA intensity, a subset previously linked to attentional processes, monitoring of internal body representation, and processing of sensory information from the genitals. This study highlights that similar brain regions are activated during subjective assessment of sexual arousal in men and women. The data further highlight the fact that SSA is a complex phenomenon made up of multiple interoceptive and attentional processes. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

SsaA, a Member of a Novel Class of Transcriptional Regulators, Controls Sansanmycin Production in Streptomyces sp. Strain SS through a Feedback Mechanism

PubMed Central

Li, Qinglian; Wang, Lifei; Xie, Yunying; Wang, Songmei; Chen, Ruxian

2013-01-01

Sansanmycins, produced by Streptomyces sp. strain SS, are uridyl peptide antibiotics with activities against Pseudomonas aeruginosa and multidrug-resistant Mycobacterium tuberculosis. In this work, the biosynthetic gene cluster of sansanmycins, comprised of 25 open reading frames (ORFs) showing considerable amino acid sequence identity to those of the pacidamycin and napsamycin gene cluster, was identified. SsaA, the archetype of a novel class of transcriptional regulators, was characterized in the sansanmycin gene cluster, with an N-terminal fork head-associated (FHA) domain and a C-terminal LuxR-type helix-turn-helix (HTH) motif. The disruption of ssaA abolished sansanmycin production, as well as the expression of the structural genes for sansanmycin biosynthesis, indicating that SsaA is a pivotal activator for sansanmycin biosynthesis. SsaA was proved to directly bind several putative promoter regions of biosynthetic genes, and comparison of sequences of the binding sites allowed the identification of a consensus SsaA binding sequence, GTMCTGACAN2TGTCAGKAC. The DNA binding activity of SsaA was inhibited by sansanmycins A and H in a concentration-dependent manner. Furthermore, sansanmycins A and H were found to directly interact with SsaA. These results indicated that SsaA strictly controls the production of sansanmycins at the transcriptional level in a feedback regulatory mechanism by sensing the accumulation of the end products. As the first characterized regulator of uridyl peptide antibiotic biosynthesis, the understanding of this autoregulatory process involved in sansanmycin biosynthesis will likely provide an effective strategy for rational improvements in the yields of these uridyl peptide antibiotics. PMID:23475969

Induction of autoimmune response to the extracellular loop of the HERG channel pore induces QTc prolongation in guinea‐pigs

PubMed Central

Fabris, Frank; Yue, Yuankun; Qu, Yongxia; Chahine, Mohamed; Sobie, Eric; Lee, Peng; Wieczorek, Rosemary; Jiang, Xian‐Cheng; Capecchi, Pier‐Leopoldo; Laghi‐Pasini, Franco; Lazzerini, Pietro‐Enea

2016-01-01

Key points Channelopathies of autoimmune origin are novel and are associated with corrected QT (QTc) prolongation and complex ventricular arrhythmias.We have recently demonstrated that anti‐SSA/Ro antibodies from patients with autoimmune diseases and with QTc prolongation on the ECG target the human ether‐à‐go‐go‐related gene (HERG) K+ channel by inhibiting the corresponding current, I Kr, at the pore region.Immunization of guinea‐pigs with a peptide (E‐pore peptide) corresponding to the extracellular loop region connecting the S5 and S6 segments of the HERG channel induces high titres of antibodies that inhibit I Kr, lengthen the action potential and cause QTc prolongation on the surface ECG. In addition, anti‐SSA/Ro‐positive sera from patients with connective tissue diseases showed high reactivity to the E‐pore peptide.The translational impact is the development of a peptide‐based approach for the diagnosis and treatment of autoimmune‐associated long QT syndrome. Abstract We recently demonstrated that anti‐SSA/52 kDa Ro antibodies (Abs) from patients with autoimmune diseases and corrected QT (QTc) prolongation directly target and inhibit the human ether‐à‐go‐go‐related gene (HERG) K+ channel at the extracellular pore (E‐pore) region, where homology with SSA/52 kDa Ro antigen was demonstrated. We tested the hypothesis that immunization of guinea‐pigs with a peptide corresponding to the E‐pore region (E‐pore peptide) will generate pathogenic inhibitory Abs and cause QTc prolongation. Guinea‐pigs were immunized with a 31‐amino‐acid peptide corresponding to the E‐pore region of HERG. On days 10–62 after immunization, ECGs were recorded and blood was sampled for the detection of E‐pore peptide Abs. Serum samples from patients with autoimmune diseases were evaluated for reactivity to E‐pore peptide by enzyme‐linked immunosorbent assay (ELISA), and histology was performed on hearts using Masson's Trichrome. Inhibition of the HERG channel was assessed by electrophysiology and by computational modelling of the human ventricular action potential. The ELISA results revealed the presence of high titres of E‐pore peptide Abs and significant QTc prolongation after immunization. High reactivity to E‐pore peptide was found using anti‐SSA/Ro Ab‐positive sera from patients with QTc prolongation. Histological data showed no evidence of fibrosis in immunized hearts. Simulations of simultaneous inhibition of repolarizing currents by anti‐SSA/Ro Ab‐positive sera showed the predominance of the HERG channel in controlling action potential duration and the QT interval. These results are the first to demonstrate that inhibitory Abs to the HERG E‐pore region induce QTc prolongation in immunized guinea‐pigs by targeting the HERG channel independently from fibrosis. The reactivity of anti‐SSA/Ro Ab‐positive sera from patients with connective tissue diseases with the E‐pore peptide opens novel pharmacotherapeutic avenues in the diagnosis and management of autoimmune‐associated QTc prolongation. PMID:27296897

Recent Results of TMD Measurements from Jefferson Lab Hall A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Xiaodong

2013-10-01

This slide-show presents results on transverse momentum distributions. The presentation covers: target single-spin asymmetry (SSA) (in parity conserving interactions); • Results of JLab Hall A polarized {sup 3}He target TMD measurement; • Semi-­inclusive deep-inelastic scattering channels (E06-010); • Target single-spin asymmetry A{sub UT}, Collins and Sivers SSA on neutron; • Double-spin asymmetry A{sub LT}, extract TMD g{sub 1T} on neutron; • Inclusive channels SSA (E06-010, E05-015, E07-013) • Target SSA: inclusive {sup 3}He(e,e’) quasi-elastic scattering; • Target SSA: inclusive {sup 3}He(e,e’) deep inelastic-elastic scattering; • New SIDIS experiments planned in Hall-A for JLab-12 GeV.

Determination of the single scattering albedo and direct radiative forcing of biomass burning aerosol with data from the MODIS (Moderate Resolution Imaging Spectroradiometer) satellite instrument

NASA Astrophysics Data System (ADS)

Zhu, Li

Biomass burning aerosols absorb and scatter solar radiation and therefore affect the energy balance of the Earth-atmosphere system. The single scattering albedo (SSA), the ratio of the scattering coefficient to the extinction coefficient, is an important parameter to describe the optical properties of aerosols and to determine the effect of aerosols on the energy balance of the planet and climate. Aerosol effects on radiation also depend strongly on surface albedo. Large uncertainties remain in current estimates of radiative impacts of biomass burning aerosols, due largely to the lack of reliable measurements of aerosol and surface properties. In this work we investigate how satellite measurements can be used to estimate the direct radiative forcing of biomass burning aerosols. We developed a method using the critical reflectance technique to retrieve SSA from the Moderate Resolution Imaging Spectroradiometer (MODIS) observed reflectance at the top of the atmosphere (TOA). We evaluated MODIS retrieved SSAs with AErosol RObotic NETwork (AERONET) retrievals and found good agreements within the published uncertainty of the AERONET retrievals. We then developed an algorithm, the MODIS Enhanced Vegetation Albedo (MEVA), to improve the representations of spectral variations of vegetation surface albedo based on MODIS observations at the discrete 0.67, 0.86, 0.47, 0.55, 1.24, 1.64, and 2.12 mu-m channels. This algorithm is validated using laboratory measurements of the different vegetation types from the Amazon region, data from the Johns Hopkins University (JHU) spectral library, and data from the U.S. Geological Survey (USGS) digital spectral library. We show that the MEVA method can improve the accuracy of flux and aerosol forcing calculations at the TOA compared to more traditional interpolated approaches. Lastly, we combine the MODIS retrieved biomass burning aerosol SSA and the surface albedo spectrum determined from the MEVA technique to calculate TOA flux and aerosol direct radiative forcing over the Amazon region and compare it with Clouds and the Earth's Radiant Energy System (CERES) satellite results. The results show that MODIS based forcing calculations present similar averaged results compared to CERES, but MODIS shows greater spatial variation of aerosol forcing than CERES. Possible reasons for these differences are explored and discussed in this work. Potential future research based on these results is discussed as well.

75 FR 52578 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-26

... collects the information on Forms SSA-1002-F3 and SSA-1003-F3 to resolve discrepancies when farm workers.... Title VIII of the Social Security Act (the Act) allows SSA to pay a monthly benefit to a qualified World...

Chemical state of chromium in sewage sludge ash based phosphorus-fertilisers.

PubMed

Vogel, Christian; Adam, Christian; Kappen, Peter; Schiller, Tara; Lipiec, Ewelina; McNaughton, Don

2014-05-01

Sewage sludge ash (SSA) based P-fertilisers were produced by thermochemical treatment of SSA with Cl-donors at approximately 1000°C. During this thermochemical process heavy metals are separated as heavy metal chlorides via the gas phase. Chromium cannot be separated under normal conditions. The risk of the development of toxic Cr(VI) during the thermochemical process was investigated. X-ray Absorption Spectroscopy measurements showed that SSA and thermochemically treated SSA with CaCl2, MgCl2 and NaCl contain Cr(III) compounds only. In contrast, treating SSA with elevated quantities of Na2CO3, to enhance the plant-availability of the phosphate phases of the fertiliser, developed approximately 10-15% Cr(VI). Furthermore, Raman microspectroscopy showed that using Mg-carbonate reduces the risk of a Cr(VI) development during thermochemical treatment. Additionally, leaching tests showed that only a Cr-water solubility>10% is an indicator for Cr(VI) in SSA based P-fertilisers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Big data for space situation awareness

NASA Astrophysics Data System (ADS)

Blasch, Erik; Pugh, Mark; Sheaff, Carolyn; Raquepas, Joe; Rocci, Peter

2017-05-01

Recent advances in big data (BD) have focused research on the volume, velocity, veracity, and variety of data. These developments enable new opportunities in information management, visualization, machine learning, and information fusion that have potential implications for space situational awareness (SSA). In this paper, we explore some of these BD trends as applicable for SSA towards enhancing the space operating picture. The BD developments could increase in measures of performance and measures of effectiveness for future management of the space environment. The global SSA influences include resident space object (RSO) tracking and characterization, cyber protection, remote sensing, and information management. The local satellite awareness can benefit from space weather, health monitoring, and spectrum management for situation space understanding. One area in big data of importance to SSA is value - getting the correct data/information at the right time, which corresponds to SSA visualization for the operator. A SSA big data example is presented supporting disaster relief for space situation awareness, assessment, and understanding.

Spectrally selective solar absorber with sharp and temperature dependent cut-off based on semiconductor nanowire arrays

NASA Astrophysics Data System (ADS)

Wang, Yang; Zhou, Lin; Zheng, Qinghui; Lu, Hong; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

2017-05-01

Spectrally selective absorbers (SSA) with high selectivity of absorption and sharp cut-off between high absorptivity and low emissivity are critical for efficient solar energy conversion. Here, we report the semiconductor nanowire enabled SSA with not only high absorption selectivity but also temperature dependent sharp absorption cut-off. By taking advantage of the temperature dependent bandgap of semiconductors, we systematically demonstrate that the absorption cut-off profile of the semiconductor-nanowire-based SSA can be flexibly tuned, which is quite different from most of the other SSA reported so far. As an example, silicon nanowire based selective absorbers are fabricated, with the measured absorption efficiency above (below) bandgap ˜97% (15%) combined with an extremely sharp absorption cut-off (transition region ˜200 nm), the sharpest SSA demonstrated so far. The demonstrated semiconductor-nanowire-based SSA can enable a high solar thermal efficiency of ≳86% under a wide range of operating conditions, which would be competitive candidates for the concentrated solar energy utilizations.

Optimism and spontaneous self-affirmation are associated with lower likelihood of cognitive impairment and greater positive affect among cancer survivors

PubMed Central

Taber, Jennifer M.; Klein, William M. P.; Ferrer, Rebecca A.; Kent, Erin E.; Harris, Peter R.

2016-01-01

Background Optimism and self-affirmation promote adaptive coping, goal achievement, and better health. Purpose To examine the associations of optimism and spontaneous self-affirmation (SSA) with physical, mental, and cognitive health and information seeking among cancer survivors. Methods Cancer survivors (n=326) completed the Health Information National Trends Survey 2013, a national survey of U.S. adults. Participants reported optimism, SSA, cognitive and physical impairment, affect, health status, and information seeking. Results Participants higher in optimism reported better health on nearly all indices examined, even when controlling for SSA. Participants higher in SSA reported lower likelihood of cognitive impairment, greater happiness and hopefulness, and greater likelihood of cancer information seeking. SSA remained significantly associated with greater hopefulness and cancer information seeking when controlling for optimism. Conclusions Optimism and SSA may be associated with beneficial health-related outcomes among cancer survivors. Given the demonstrated malleability of self-affirmation, these findings represent important avenues for future research. PMID:26497697

Optimism and Spontaneous Self-affirmation are Associated with Lower Likelihood of Cognitive Impairment and Greater Positive Affect among Cancer Survivors.

PubMed

Taber, Jennifer M; Klein, William M P; Ferrer, Rebecca A; Kent, Erin E; Harris, Peter R

2016-04-01

Optimism and self-affirmation promote adaptive coping, goal achievement, and better health. The aim of this study is to examine the associations of optimism and spontaneous self-affirmation (SSA) with physical, mental, and cognitive health and information seeking among cancer survivors. Cancer survivors (n = 326) completed the Health Information National Trends Survey 2013, a national survey of US adults. Participants reported optimism, SSA, cognitive and physical impairment, affect, health status, and information seeking. Participants higher in optimism reported better health on nearly all indices examined, even when controlling for SSA. Participants higher in SSA reported lower likelihood of cognitive impairment, greater happiness and hopefulness, and greater likelihood of cancer information seeking. SSA remained significantly associated with greater hopefulness and cancer information seeking when controlling for optimism. Optimism and SSA may be associated with beneficial health-related outcomes among cancer survivors. Given the demonstrated malleability of self-affirmation, these findings represent important avenues for future research.

Determination of the GABA analogue succinic semialdehyde in urine and cerebrospinal fluid by dinitrophenylhydrazine derivatization and liquid chromatography-tandem mass spectrometry: application to SSADH deficiency.

PubMed

Struys, E A; Jansen, E E W; Gibson, K M; Jakobs, C

2005-01-01

Succinic semialdehyde (SSA) accumulates in the inborn error of meta- bolism succinic semialdehyde dehydrogenase deficiency owing to impaired enzymatic conversion to succinic acid. We developed a stable-isotope dilution liquid chromato- graphy-tandem mass spectrometry method for the determination of SSA in urine and cerebrospinal fluid samples. Stable-isotope-labelled [13C4]SSA, serving as internal standard, was prepared by reaction of ninhydrin with L-[13C5]glutamic acid. SSA in body fluids was converted to its dinitrophenylhydrazine (DNPH) derivative, without sample purification prior to the derivatization procedure. The DNPH derivative of SSA was injected onto a C18 analytical column and chromatography was performed by isocratic elution. Detection was accomplished by tandem mass spectrometry operating in the negative multiple-reaction monitoring mode. The limit of detection was 10 nmol/L and the calibration curves over the range 0-500 pmol of SSA showed good linearity (r2 > 0.99). The intra-day coefficient of variation (n = 10) for urine was 2.7% and inter-day coefficient of variation (n = 5) for urine was 8.5%. The average recoveries performed on two levels by enriching urine and cerebrospinal fluid samples ranged between 85 and 115%, with coefficients of variation < 8%. The method enabled the first determination of normal values for SSA in urine and pathological values of SSA in urine and cerebrospinal fluid samples derived from patients with succinic semialdehyde dehydrogenase deficiency.

The development of the MELiSSA Pilot Plant Facility

NASA Astrophysics Data System (ADS)

Godia, Francesc; Dussap, Claude-Gilles; Dixon, Mike; Peiro, Enrique; Fossen, Arnaud; Lamaze, Brigitte; Brunet, Jean; Demey, Dries; Mas-Albaigès, Joan L.

MELiSSA (Micro-Ecological Life Support System Alternative) is a closed artificial ecosystem intended as a tool for the development of a bio-regenerative life support system for longterm manned missions. The MELiSSA loop is formed by five interconnected compartments, organized in three different loops (solid, liquid and gas). This compartments are microbial bioreactors and higher plant chambers. The MELiSSA Pilot Plant facility has been designed to achieve the preliminary terrestrial demonstration of the MELiSSA concept at pilot scale, using animals as a model for the crew compartent. The experience gained in the operation of such a facility will be highly relevant for planning future life support systems in Space. In this communication, the latests developments in the MELiSSA Pilot Plant will be reported. Particularly, the completion of the design phase and instalation of all the different compartments will be discussed in detail. Each of the compartments had to be designed and constructed according to very specific characteristics, associated to the biological systems to be cultured, as part of the complete MELiSSA loop (anerobic, oxygenic, thermophilic, heterotrophic, autotrophic, axenic, photosynthetic, etc.). Additionally, the sizing of each reactor (ranging from 8 to 100 Liters, depending of each particular compartment) should compile with the global integration scenario proposed, and with the final goal of connection of all compartments to provide a demonstration of the MELiSSA concept, and generate data for the design and operation of future biological life support systems.

75 FR 5166 - Privacy Act of 1974, as Amended; Computer Matching Program (Social Security Administration...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

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Relative frequencies of constrained events in stochastic processes: An analytical approach.

PubMed

Rusconi, S; Akhmatskaya, E; Sokolovski, D; Ballard, N; de la Cal, J C

2015-10-01

The stochastic simulation algorithm (SSA) and the corresponding Monte Carlo (MC) method are among the most common approaches for studying stochastic processes. They relies on knowledge of interevent probability density functions (PDFs) and on information about dependencies between all possible events. Analytical representations of a PDF are difficult to specify in advance, in many real life applications. Knowing the shapes of PDFs, and using experimental data, different optimization schemes can be applied in order to evaluate probability density functions and, therefore, the properties of the studied system. Such methods, however, are computationally demanding, and often not feasible. We show that, in the case where experimentally accessed properties are directly related to the frequencies of events involved, it may be possible to replace the heavy Monte Carlo core of optimization schemes with an analytical solution. Such a replacement not only provides a more accurate estimation of the properties of the process, but also reduces the simulation time by a factor of order of the sample size (at least ≈10(4)). The proposed analytical approach is valid for any choice of PDF. The accuracy, computational efficiency, and advantages of the method over MC procedures are demonstrated in the exactly solvable case and in the evaluation of branching fractions in controlled radical polymerization (CRP) of acrylic monomers. This polymerization can be modeled by a constrained stochastic process. Constrained systems are quite common, and this makes the method useful for various applications.

77 FR 67435 - Agency Information Collection Activities: Proposed Request and Comment Request

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2012-11-09

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75 FR 9992 - Agency Information Collection Activities: Proposed Request and Comment Request

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2010-03-04

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76 FR 38449 - Agency Information Collection Activities; Proposed Request and Comment Request

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2011-06-30

... verifying the requester's identity, SSA uses the information from BEVE to provide the POI statement. SSA...: 2 minutes. Estimated Annual Burden: 1,067 hours. 3. Teacher Questionnaire and Request for...), SSA obtains information about the child's functioning from teachers, parents, and others who observe...

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75 FR 51154 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Department of the Treasury...

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76 FR 41685 - Electronic Substitutions for Form SSA-538

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2011-07-15

... SOCIAL SECURITY ADMINISTRATION 20 CFR Part 416 [Docket No. SSA-2009-0027] RIN 0960-AH02 Electronic Substitutions for Form SSA-538 AGENCY: Social Security Administration. ACTION: Final rule with request for... children alleging disability or continuing disability under title XVI of the Social Security Act (Act...

Solving Lauricella string scattering amplitudes through recurrence relations

NASA Astrophysics Data System (ADS)

Lai, Sheng-Hong; Lee, Jen-Chi; Lee, Taejin; Yang, Yi

2017-09-01

We show that there exist infinite number of recurrence relations valid for all energies among the open bosonic string scattering amplitudes (SSA) of three tachyons and one arbitrary string state, or the Lauricella SSA. Moreover, these infinite number of recurrence relations can be used to solve all the Lauricella SSA and express them in terms of one single four tachyon amplitude. These results extend the solvability of SSA at the high energy, fixed angle scattering limit and those at the Regge scattering limit discovered previously to all kinematic regimes.

Ground Wave Emergency Network Final Operational Capability: Environmental Assessment for Central Utah Relay Node, Site Number RN 8C920UT

DTIC Science & Technology

1993-04-16

Utah and Juab counties, centered approximately 5 miles northwest of the town of Nephi in Juab County, in the Basin and Range portion of the...3.2 to 3.6 of this EA. Permanent streams are rare in the SSA; no stream leaves the SSA because each of the valleys forms a closed basin . The northern...the SSA is differentiated by distinct topographical basins . All runoff in the northern portion of the SSA drains into Utah Lake. Runoff in the

Densovirus associated with sea-star wasting disease and mass mortality

USGS Publications Warehouse

Hewson, Ian; Button, Jason B.; Gudenkauf, Brent M.; Miner, Benjamin; Newton, Alisa L.; Gaydos, Joseph K.; Wynne, Janna; Groves, Cathy L.; Hendler, Gordon; Murray, Michael; Fradkin, Steven; Breitbart, Mya; Fahsbender, Elizabeth; Lafferty, Kevin D.; Kilpatrick, A. Marm; Miner, C. Melissa; Raimondi, Peter T.; Lahner, Lesanna L.; Friedman, Carolyn S.; Danielson, Stephen D.; Haulena, Martin; Marliave, Jeffrey; Burge, Colleen A.; Eisenlord, Morgan E.; Harvell, C. Drew

2015-01-01

Populations of at least 20 asteroid species on the Northeast Pacific Coast have recently experienced an extensive outbreak of sea-star (asteroid) wasting disease (SSWD). The disease leads to behavioral changes, lesions, loss of turgor, limb autotomy, and death characterized by rapid degradation (“melting”). Here, we present evidence from experimental challenge studies and field observations that link the mass mortalities to a densovirus (Parvoviridae). Virus-sized material (i.e., <0.2 μm) from symptomatic tissues that was inoculated into asymptomatic asteroids consistently resulted in SSWD signs whereas animals receiving heat-killed (i.e., control) virus-sized inoculum remained asymptomatic. Viral metagenomic investigations revealed the sea star-associated densovirus (SSaDV) as the most likely candidate virus associated with tissues from symptomatic asteroids. Quantification of SSaDV during transmission trials indicated that progression of SSWD paralleled increased SSaDV load. In field surveys, SSaDV loads were more abundant in symptomatic than in asymptomatic asteroids. SSaDV could be detected in plankton, sediments and in nonasteroid echinoderms, providing a possible mechanism for viral spread. SSaDV was detected in museum specimens of asteroids from 1942, suggesting that it has been present on the North American Pacific Coast for at least 72 y. SSaDV is therefore the most promising candidate disease agent responsible for asteroid mass mortality.

Saikosaponin A Alleviates Symptoms of Attention Deficit Hyperactivity Disorder through Downregulation of DAT and Enhancing BDNF Expression in Spontaneous Hypertensive Rats.

PubMed

Jichao, Sun; Xinmin, Han; Xianguo, Ren; Dongqi, Yin; Rongyi, Zhou; Shuang, Lei; Yue, You; Yuchen, Song; Jingnan, Ying

2017-01-01

The disturbed dopamine availability and brain-derived neurotrophic factor (BDNF) expression are due in part to be associated with attention deficit hyperactivity disorder (ADHD). In this study, we investigated the therapeutical effect of saikosaponin a (SSa) isolated from Bupleurum Chinese DC, against spontaneously hypertensive rat (SHR) model of ADHD. Methylphenidate and SSa were orally administered for 3 weeks. Activity was assessed by open-field test and Morris water maze test. Dopamine (DA) and BDNF were determined in specific brain regions. The mRNA or protein expression of tyrosine hydroxylase (TH), dopamine transporter (DAT), and vesicles monoamine transporter (VMAT) was also studied. Both MPH and SSa reduced hyperactivity and improved the spatial learning memory deficit in SHRs. An increased DA concentration in the prefrontal cortex (PFC) and striatum was also observed after treating with the SSa. The increased DA concentration may partially be attributed to the decreased mRNA and protein expression of DAT in PFC while SSa exhibited no significant effects on the mRNA expression of TH and VMAT in PFC of SHRs. In addition, BDNF expression in SHRs was also increased after treating with SSa or MPH. The obtained result suggested that SSa may be a potential drug for treating ADHD.

Densovirus associated with sea-star wasting disease and mass mortality

PubMed Central

Hewson, Ian; Button, Jason B.; Gudenkauf, Brent M.; Miner, Benjamin; Newton, Alisa L.; Gaydos, Joseph K.; Wynne, Janna; Groves, Cathy L.; Hendler, Gordon; Murray, Michael; Fradkin, Steven; Breitbart, Mya; Fahsbender, Elizabeth; Lafferty, Kevin D.; Kilpatrick, A. Marm; Miner, C. Melissa; Raimondi, Peter; Lahner, Lesanna; Friedman, Carolyn S.; Daniels, Stephen; Haulena, Martin; Marliave, Jeffrey; Burge, Colleen A.; Eisenlord, Morgan E.; Harvell, C. Drew

2014-01-01

Populations of at least 20 asteroid species on the Northeast Pacific Coast have recently experienced an extensive outbreak of sea-star (asteroid) wasting disease (SSWD). The disease leads to behavioral changes, lesions, loss of turgor, limb autotomy, and death characterized by rapid degradation (“melting”). Here, we present evidence from experimental challenge studies and field observations that link the mass mortalities to a densovirus (Parvoviridae). Virus-sized material (i.e., <0.2 μm) from symptomatic tissues that was inoculated into asymptomatic asteroids consistently resulted in SSWD signs whereas animals receiving heat-killed (i.e., control) virus-sized inoculum remained asymptomatic. Viral metagenomic investigations revealed the sea star-associated densovirus (SSaDV) as the most likely candidate virus associated with tissues from symptomatic asteroids. Quantification of SSaDV during transmission trials indicated that progression of SSWD paralleled increased SSaDV load. In field surveys, SSaDV loads were more abundant in symptomatic than in asymptomatic asteroids. SSaDV could be detected in plankton, sediments and in nonasteroid echinoderms, providing a possible mechanism for viral spread. SSaDV was detected in museum specimens of asteroids from 1942, suggesting that it has been present on the North American Pacific Coast for at least 72 y. SSaDV is therefore the most promising candidate disease agent responsible for asteroid mass mortality. PMID:25404293

Densovirus associated with sea-star wasting disease and mass mortality.

PubMed

Hewson, Ian; Button, Jason B; Gudenkauf, Brent M; Miner, Benjamin; Newton, Alisa L; Gaydos, Joseph K; Wynne, Janna; Groves, Cathy L; Hendler, Gordon; Murray, Michael; Fradkin, Steven; Breitbart, Mya; Fahsbender, Elizabeth; Lafferty, Kevin D; Kilpatrick, A Marm; Miner, C Melissa; Raimondi, Peter; Lahner, Lesanna; Friedman, Carolyn S; Daniels, Stephen; Haulena, Martin; Marliave, Jeffrey; Burge, Colleen A; Eisenlord, Morgan E; Harvell, C Drew

2014-12-02

Populations of at least 20 asteroid species on the Northeast Pacific Coast have recently experienced an extensive outbreak of sea-star (asteroid) wasting disease (SSWD). The disease leads to behavioral changes, lesions, loss of turgor, limb autotomy, and death characterized by rapid degradation ("melting"). Here, we present evidence from experimental challenge studies and field observations that link the mass mortalities to a densovirus (Parvoviridae). Virus-sized material (i.e., <0.2 μm) from symptomatic tissues that was inoculated into asymptomatic asteroids consistently resulted in SSWD signs whereas animals receiving heat-killed (i.e., control) virus-sized inoculum remained asymptomatic. Viral metagenomic investigations revealed the sea star-associated densovirus (SSaDV) as the most likely candidate virus associated with tissues from symptomatic asteroids. Quantification of SSaDV during transmission trials indicated that progression of SSWD paralleled increased SSaDV load. In field surveys, SSaDV loads were more abundant in symptomatic than in asymptomatic asteroids. SSaDV could be detected in plankton, sediments and in nonasteroid echinoderms, providing a possible mechanism for viral spread. SSaDV was detected in museum specimens of asteroids from 1942, suggesting that it has been present on the North American Pacific Coast for at least 72 y. SSaDV is therefore the most promising candidate disease agent responsible for asteroid mass mortality.

Genetic Requirements for the Single-Strand Annealing Pathway of Double-Strand Break Repair in Saccharomyces Cerevisiae

PubMed Central

Ivanov, E. L.; Sugawara, N.; Fishman-Lobell, J.; Haber, J. E.

1996-01-01

HO endonuclease-induced double-strand breaks (DSBs) within a direct duplication of Escherichia coli lacZ genes are repaired either by gene conversion or by single-strand annealing (SSA), with >80% being SSA. Previously it was demonstrated that the RAD52 gene is required for DSB-induced SSA. In the present study, the effects of other genes belonging to the RAD52 epistasis group were analyzed. We show that RAD51, RAD54, RAD55, and RAD57 genes are not required for SSA irrespective of whether recombination occurred in plasmid or chromosomal DNA. In both plasmid and chromosomal constructs with homologous sequences in direct orientation, the proportion of SSA events over gene conversion was significantly elevated in the mutant strains. However, gene conversion was not affected when the two lacZ sequences were in inverted orientation. These results suggest that there is a competition between SSA and gene conversion processes that favors SSA in the absence of RAD51, RAD54, RAD55 and RAD57. Mutations in RAD50 and XRS2 genes do not prevent the completion, but markedly retard the kinetics, of DSB repair by both mechanisms in the lacZ direct repeat plasmid, a result resembling the effects of these genes during mating-type (MAT) switching. PMID:8849880

Simulated microgravity allows to demonstrate cell-to-cell communication in bacteria

NASA Astrophysics Data System (ADS)

Mastroleo, Felice; van Houdt, Rob; Mergeay, Max; Hendrickx, Larissa; Wattiez, Ruddy; Leys, Natalie

Through the MELiSSA project, the European Space Agency aims to develop a closed life support system for oxygen, water and food production to support human life in space in forth-coming long term space exploration missions. This production is based on the recycling of the missions organic waste, including CO2 and minerals. The photosynthetic bacterium Rhodospir-illum rubrum S1H is used in MELiSSA to degrade organics with light energy and is the first MELiSSA organism that has been studied in space related environmental conditions (Mastroleo et al., 2009). It was tested in actual space flight to the International Space Station (ISS) as well as in ground simulations of ISS-like ionizing radiation and microgravity. In the present study, R. rubrum S1H was cultured in liquid medium in 2 devices simulating microgravity conditions, i.e. the Rotating Wall Vessel (RWV) and the Random Positioning Machine (RPM). The re-sponse of the bacterium was evaluated at both the transcriptomic and proteomic levels using respectively a dedicated whole-genome microarray and high-throughput gel-free quantitative proteomics. Both at transcriptomic and proteomic level, the bacterium showed a significant response to cultivation in simulated microgravity. The response to low fluid shear modeled microgravity in RWV was different than to randomized microgravity in RPM. Nevertheless, both tests pointed out a change in and a likely interrelation between cell-to-cell communica-tion (i.e. quorum sensing) and cell pigmentation (i.e. photosynthesis) for R. rubrum S1H in microgravity conditions. A new type of cell-to-cell communication molecule in R. rubrum S1H was discovered and characterized. It is hypothised that the lack of convection currents and the fluid quiescence in (simulated) microgravity limits communications molecules to be spread throughout the medium. Cultivation in this new artificial environment of simulated micro-gravity has showed new properties of this well know bacterium. Understanding how cell-to-cell communication regulates photosynthesis and potentially cell aggregation may be an unique tool to understand, characterize and then optimize biodegradation processes in photobioreactors, in space or on Earth. Mastroleo F., Van Houdt R., Leroy B., Benotmane M. A., Janssen A., Mergeay M., Vanhavere F., Hendrickx L., Wattiez R. and Leys N. Experimental design and environmental parameters affect Rhodospirillum rubrum S1H response to space flight. ISME J 2009;3:1402-1419. The presented work was financially supported by the European Space Agency (ESA-PRODEX), the Belgian Science Policy (Belspo) (PRODEX agreements No C90247 No 90094) and the SCK•CEN PhD AWM grant of F. Mastroleo. We are grateful to C. Lasseur and C. Paillé, both from ESTEC/ESA, for their constant support and advice.

ESA SSA Programme in support of Space Weather forecasting

NASA Astrophysics Data System (ADS)

Luntama, J.; Glover, A.; Hilgers, A. M.

2010-12-01

In 2009 European Space Agency (ESA) started a new programme called Space Situational Awareness (SSA) Preparatory Programme. The objective of the programme is to support the European independent utilisation of and access to space research or services. This will be performed through providing timely and quality data, information, services and knowledge regarding the environment, the threats and the sustainable exploitation of the outer space surrounding the planet Earth. SSA serves the implementation of the strategic missions of the European Space Policy based on the peaceful uses of the outer space by all states, by supporting the autonomous capacity to securely and safely operate the critical European space infrastructures. The SSA Preparatory Program will establish the initial elements that will eventually lead into the full deployment of the European SSA services. The SWE Segment of the SSA will provide user services related to the monitoring of the Sun, the solar wind, the radiation belts, the magnetosphere and the ionosphere. These services will include near real time information and forecasts about the characteristics of the space environment and predictions of space weather impacts on sensitive spaceborne and ground based infrastructure. The SSA SWE system will also include establishment of a permanent database for analysis, model development and scientific research. These services are will support a wide variety of user domains including spacecraft designers, spacecraft operators, human space flights, users and operators of transionospheric radio links, and space weather research community. The precursor SWE services to be established starting in 2010 will include a selected subset of these services based on pre-existing space weather applications and services in Europe. This paper will present the key characteristics of the SSA SWE system that is currently being designed. The presentation will focus on the system characteristics that support space weather forecasting and the related services. The presentation will show results from the analysis of the existing European assets and the identified development needs in the mid and long term future to ensure forecasting capability for the services requested the by SSA SWE users. The analysis covers the future SSA SWE space segment and the service development needs for the ground segment.

Multivariate singular spectrum analysis and the road to phase synchronization

NASA Astrophysics Data System (ADS)

Groth, Andreas; Ghil, Michael

2010-05-01

Singular spectrum analysis (SSA) and multivariate SSA (M-SSA) are based on the classical work of Kosambi (1943), Loeve (1945) and Karhunen (1946) and are closely related to principal component analysis. They have been introduced into information theory by Bertero, Pike and co-workers (1982, 1984) and into dynamical systems analysis by Broomhead and King (1986a,b). Ghil, Vautard and associates have applied SSA and M-SSA to the temporal and spatio-temporal analysis of short and noisy time series in climate dynamics and other fields in the geosciences since the late 1980s. M-SSA provides insight into the unknown or partially known dynamics of the underlying system by decomposing the delay-coordinate phase space of a given multivariate time series into a set of data-adaptive orthonormal components. These components can be classified essentially into trends, oscillatory patterns and noise, and allow one to reconstruct a robust "skeleton" of the dynamical system's structure. For an overview we refer to Ghil et al. (Rev. Geophys., 2002). In this talk, we present M-SSA in the context of synchronization analysis and illustrate its ability to unveil information about the mechanisms behind the adjustment of rhythms in coupled dynamical systems. The focus of the talk is on the special case of phase synchronization between coupled chaotic oscillators (Rosenblum et al., PRL, 1996). Several ways of measuring phase synchronization are in use, and the robust definition of a reasonable phase for each oscillator is critical in each of them. We illustrate here the advantages of M-SSA in the automatic identification of oscillatory modes and in drawing conclusions about the transition to phase synchronization. Without using any a priori definition of a suitable phase, we show that M-SSA is able to detect phase synchronization in a chain of coupled chaotic oscillators (Osipov et al., PRE, 1996). Recently, Muller et al. (PRE, 2005) and Allefeld et al. (Intl. J. Bif. Chaos, 2007) have demonstrated the usefulness of principal component analysis in detecting phase synchronization from multivariate time series. The present talk provides a generalization of this idea and presents a robust implementation thereof via M-SSA.

DVD-COOP: Innovative Conjunction Prediction Using Voronoi-filter based on the Dynamic Voronoi Diagram of 3D Spheres

NASA Astrophysics Data System (ADS)

Cha, J.; Ryu, J.; Lee, M.; Song, C.; Cho, Y.; Schumacher, P.; Mah, M.; Kim, D.

Conjunction prediction is one of the critical operations in space situational awareness (SSA). For geospace objects, common algorithms for conjunction prediction are usually based on all-pairwise check, spatial hash, or kd-tree. Computational load is usually reduced through some filters. However, there exists a good chance of missing potential collisions between space objects. We present a novel algorithm which both guarantees no missing conjunction and is efficient to answer to a variety of spatial queries including pairwise conjunction prediction. The algorithm takes only O(k log N) time for N objects in the worst case to answer conjunctions where k is a constant which is linear to prediction time length. The proposed algorithm, named DVD-COOP (Dynamic Voronoi Diagram-based Conjunctive Orbital Object Predictor), is based on the dynamic Voronoi diagram of moving spherical balls in 3D space. The algorithm has a preprocessing which consists of two steps: The construction of an initial Voronoi diagram (taking O(N) time on average) and the construction of a priority queue for the events of topology changes in the Voronoi diagram (taking O(N log N) time in the worst case). The scalability of the proposed algorithm is also discussed. We hope that the proposed Voronoi-approach will change the computational paradigm in spatial reasoning among space objects.

77 FR 50204 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

...(c)(1)&(2), 416.2201(a)&(b), 416.2221(a), 34 CFR 361--0960- 0310. State Vocational Rehabilitation (VR) agencies submit Form SSA-199 to SSA to obtain reimbursement of costs incurred for providing VR services. SSA requires state VR agencies to submit reimbursement claims for the following categories: (1...

77 FR 49849 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Office of Child Support...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-17

...: Social Security Administration (SSA). ACTION: Notice of a renewal of an existing computer-matching... INFORMATION: A. General The Computer Matching and Privacy Protection Act of 1988 (Public Law (Pub. L.) 100-503... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2012-0021] Privacy Act of 1974, as Amended...

75 FR 32833 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Office of Personnel Management...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-09

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA-2009-0077] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Office of Personnel Management (OPM))--Match 1307 AGENCY: Social Security... INFORMATION: A. General The Computer Matching and Privacy Protection Act of 1988 (Public Law (Pub. L.) 100-503...

77 FR 27108 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Office of Child Support...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-08

...: Social Security Administration (SSA). ACTION: Notice of a renewal of an existing computer matching... protections for such persons. The Privacy Act, as amended, regulates the use of computer matching by Federal... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2012-0010] Privacy Act of 1974, as Amended...

78 FR 37647 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Railroad Retirement Board (RRB...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-21

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2013-0010] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Railroad Retirement Board (RRB))--Match Number 1006 AGENCY: Social Security Administration. ACTION: Notice of a renewal of an existing computer matching program that will expire on...

78 FR 51264 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Department of the Treasury...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-20

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77 FR 24756 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Department of Labor (DOL))-Match...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-25

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2011-0084] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Department of Labor (DOL))--Match Number 1003 AGENCY: Social Security... above. SUPPLEMENTARY INFORMATION: A. General The Computer Matching and Privacy Protection Act of 1988...

77 FR 6620 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/the States); Match 6000 and 6003

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2011-0102] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ the States); Match 6000 and 6003 AGENCY: Social Security Administration..., as shown above. SUPPLEMENTARY INFORMATION: A. General The Computer Matching and Privacy Protection...

75 FR 18251 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Internal Revenue Service (IRS...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-09

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA-2009-0066] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Internal Revenue Service (IRS))--Match 1305 AGENCY: Social Security... INFORMATION: A. General The Computer Matching and Privacy Protection Act of 1988 (Public Law (Pub. L.) 100-503...

76 FR 12398 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Bureau of the Public Debt (BPD...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-07

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2010-0034] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Bureau of the Public Debt (BPD))--Match Number 1304 AGENCY: Social Security... as shown above. SUPPLEMENTARY INFORMATION: A. General The Computer Matching and Privacy Protection...

77 FR 24757 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Department of Labor (DOL))-Match...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-25

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2011-0083] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Department of Labor (DOL))--Match Number 1015 AGENCY: Social Security... regarding protections for such persons. The Privacy Act, as amended, regulates the use of computer matching...

75 FR 62623 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Internal Revenue Service (IRS...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2010-0015] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Internal Revenue Service (IRS))--Match Number 1016 AGENCY: Social Security... regarding protections for such persons. The Privacy Act, as amended, regulates the use of computer matching...

75 FR 59780 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Railroad Retirement Board (RRB...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-28

... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA 2010-0040] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ Railroad Retirement Board (RRB))--Match Number 1006 AGENCY: Social Security...: A. General The Computer Matching and Privacy Protection Act of 1988 (Pub. L.) 100-503), amended the...

78 FR 12128 - Privacy Act of 1974; Computer Matching Program (SSA/Department of the Treasury, Internal Revenue...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-21

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20 CFR 411.330 - How will SSA evaluate an EN's performance?

Code of Federal Regulations, 2014 CFR

2014-04-01

... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false How will SSA evaluate an EN's performance? 411.330 Section 411.330 Employees' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Employment Networks § 411.330 How will SSA evaluate an EN's performance? (a) We will...

20 CFR 411.330 - How will SSA evaluate an EN's performance?

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false How will SSA evaluate an EN's performance? 411.330 Section 411.330 Employees' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Employment Networks § 411.330 How will SSA evaluate an EN's performance? (a) We will...

20 CFR 411.330 - How will SSA evaluate an EN's performance?

Code of Federal Regulations, 2012 CFR

2012-04-01

... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false How will SSA evaluate an EN's performance? 411.330 Section 411.330 Employees' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Employment Networks § 411.330 How will SSA evaluate an EN's performance? (a) We will...

20 CFR 411.330 - How will SSA evaluate an EN's performance?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false How will SSA evaluate an EN's performance? 411.330 Section 411.330 Employees' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Employment Networks § 411.330 How will SSA evaluate an EN's performance? (a) We will...

20 CFR 411.330 - How will SSA evaluate an EN's performance?

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false How will SSA evaluate an EN's performance? 411.330 Section 411.330 Employees' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Employment Networks § 411.330 How will SSA evaluate an EN's performance? (a) We will...

Problem Gambling among Young People in Sub-Saharan Africa.

PubMed

Ssewanyana, Derrick; Bitanihirwe, Byron

2018-01-01

Gambling is a cross-cultural and global activity which typically involves the wagering of money or an item of monetary value on an outcome that is governed by chance. Although gambling is positioned as a legitimate recreational and leisure activity within sub-Saharan Africa (SSA), there is widespread recognition among healthcare professionals and policy-makers that gambling has the capacity to become dysfunctional in a minority. Emerging knowledge suggests that problem gambling is rapidly evolving in to a public health concern in SSA, especially among youth. This article focuses on problem gambling among young people in SSA with an emphasis on three key themes: (1) gambling behavior and patterns in SSA; (2) public health and socioeconomic implications of gambling in SSA; and (3) public health policies and interventions for addressing this issue. We believe that collaborative efforts between government, prevention specialists, legislators, researchers, treatment providers, and other stake holders can influence the uptake of research findings necessary to implement social policies and design effective public health intervention options to combat problem gambling and its associated implications among young people in SSA.

Problem Gambling among Young People in Sub-Saharan Africa

PubMed Central

Ssewanyana, Derrick; Bitanihirwe, Byron

2018-01-01

Gambling is a cross-cultural and global activity which typically involves the wagering of money or an item of monetary value on an outcome that is governed by chance. Although gambling is positioned as a legitimate recreational and leisure activity within sub-Saharan Africa (SSA), there is widespread recognition among healthcare professionals and policy-makers that gambling has the capacity to become dysfunctional in a minority. Emerging knowledge suggests that problem gambling is rapidly evolving in to a public health concern in SSA, especially among youth. This article focuses on problem gambling among young people in SSA with an emphasis on three key themes: (1) gambling behavior and patterns in SSA; (2) public health and socioeconomic implications of gambling in SSA; and (3) public health policies and interventions for addressing this issue. We believe that collaborative efforts between government, prevention specialists, legislators, researchers, treatment providers, and other stake holders can influence the uptake of research findings necessary to implement social policies and design effective public health intervention options to combat problem gambling and its associated implications among young people in SSA. PMID:29479527

Is sex-selective abortion morally justified and should it be prohibited?

PubMed

Rogers, Wendy; Ballantyne, Angela; Draper, Heather

2007-11-01

In this paper we argue that sex-selective abortion (SSA) cannot be morally justified and that it should be prohibited. We present two main arguments against SSA. First, we present reasons why the decision for a woman to seek SSA in cultures with strong son-preference cannot be regarded as autonomous on either a narrow or a broad account of autonomy. Second, we identify serious harms associated with SSA including perpetuation of discrimination against women, disruption to social and familial networks, and increased violence against women. For these reasons, SSA should be prohibited by law, and such laws should be enforced. Finally, we describe additional strategies for decreasing son-preference. Some of these strategies rely upon highlighting the disadvantages of women becoming scarce, such as lack of brides and daughters-in-law to care for elderly parents. We should, however, be cautious not to perpetuate the view that the purpose of women is to be the consorts for, and carers of, men, and the providers of children. Arguments against SSA should be located within a concerted effort to ensure greater, deeper social and cultural equality between the sexes.

Laboratory estimate of the regional shortwave refractive index and single scattering albedo of mineral dust from major sources worldwide

NASA Astrophysics Data System (ADS)

Di Biagio, C.; Formenti, P.; Caponi, L.; Cazaunau, M.; Pangui, E.; Journet, E.; Nowak, S.; Caquineau, S.; Andreae, M. O.; Kandler, K.; Saeed, T.; Piketh, S.; Seibert, D.; Williams, E.; Balkanski, Y.; Doussin, J. F.

2017-12-01

Mineral dust is one of the most abundant aerosol species in the atmosphere and strongly contributes to the global and regional direct radiative effect. Still large uncertainties persist on the magnitude and overall sign of the dust direct effect, where indeed one of the main unknowns is how much mineral dust absorbs light in the shortwave (SW) spectral range. Aerosol absorption is represented both by the imaginary part (k) of the complex refractive index or the single scattering albedo (SSA, i.e. the ratio of the scattering to extinction coefficient). In this study we present a new dataset of SW complex refractive indices and SSA for mineral dust aerosols obtained from in situ measurements in the 4.2 m3 CESAM simulation chamber at LISA (Laboratoire Interuniversitaire des Systemes Atmospheriques) in Créteil, France. Investigated dust aerosol samples were issued from major desert sources worldwide, including the African Sahara and Sahel, Eastern Asia, the Middle East, Southern Africa, Australia, and the Americas, with differing iron oxides content. Results from the present study provide a regional mapping of the SW absorption by dust and show that the imaginary part of the refractive index largely varies (by up to a factor 6, 0.003-0.02 at 370 nm and 0.001-0.003 at 950 nm) for the different source areas due to the change in the particle iron oxide content. The SSA for dust varies between 0.75-0.90 at 370 nm and 0.95-0.99 at 950 nm, with the largest absorption observed for Sahelian and Australian dust aerosols. Our range of variability for k and SSA is well bracketed by already published literature estimates, but suggests that regional‒dependent values should be used in models. The possible relationship between k and the dust iron oxides content is investigated with the aim of providing a parameterization of the regional‒dependent dust absorption to include in climate models.

High concentration agglomerate dynamics at high temperatures.

PubMed

Heine, M C; Pratsinis, S E

2006-11-21

The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

Embedding Dimension Selection for Adaptive Singular Spectrum Analysis of EEG Signal.

PubMed

Xu, Shanzhi; Hu, Hai; Ji, Linhong; Wang, Peng

2018-02-26

The recorded electroencephalography (EEG) signal is often contaminated with different kinds of artifacts and noise. Singular spectrum analysis (SSA) is a powerful tool for extracting the brain rhythm from a noisy EEG signal. By analyzing the frequency characteristics of the reconstructed component (RC) and the change rate in the trace of the Toeplitz matrix, it is demonstrated that the embedding dimension is related to the frequency bandwidth of each reconstructed component, in consistence with the component mixing in the singular value decomposition step. A method for selecting the embedding dimension is thereby proposed and verified by simulated EEG signal based on the Markov Process Amplitude (MPA) EEG Model. Real EEG signal is also collected from the experimental subjects under both eyes-open and eyes-closed conditions. The experimental results show that based on the embedding dimension selection method, the alpha rhythm can be extracted from the real EEG signal by the adaptive SSA, which can be effectively utilized to distinguish between the eyes-open and eyes-closed states.

Arctic Sea Salt Aerosol from Blowing Snow and Sea Ice Surfaces - a Missing Natural Source in Winter

NASA Astrophysics Data System (ADS)

Frey, M. M.; Norris, S. J.; Brooks, I. M.; Nishimura, K.; Jones, A. E.

2015-12-01

Atmospheric particles in the polar regions consist mostly of sea salt aerosol (SSA). SSA plays an important role in regional climate change through influencing the surface energy balance either directly or indirectly via cloud formation. SSA irradiated by sunlight also releases very reactive halogen radicals, which control concentrations of ozone, a pollutant and greenhouse gas. However, models under-predict SSA concentrations in the Arctic during winter pointing to a missing source. It has been recently suggested that salty blowing snow above sea ice, which is evaporating, to be that source as it may produce more SSA than equivalent areas of open ocean. Participation in the 'Norwegian Young Sea Ice Cruise (N-ICE 2015)' on board the research vessel `Lance' allowed to test this hypothesis in the Arctic sea ice zone during winter. Measurements were carried out from the ship frozen into the pack ice North of 80º N during February to March 2015. Observations at ground level (0.1-2 m) and from the ship's crows nest (30 m) included number concentrations and size spectra of SSA (diameter range 0.3-10 μm) as well as snow particles (diameter range 50-500 μm). During and after blowing snow events significant SSA production was observed. In the aerosol and snow phase sulfate is fractionated with respect to sea water, which confirms sea ice surfaces and salty snow, and not the open ocean, to be the dominant source of airborne SSA. Aerosol shows depletion in bromide with respect to sea water, especially after sunrise, indicating photochemically driven release of bromine. We discuss the SSA source strength from blowing snow in light of environmental conditions (wind speed, atmospheric turbulence, temperature and snow salinity) and recommend improved model parameterisations to estimate regional aerosol production. N-ICE 2015 results are then compared to a similar study carried out previously in the Weddell Sea during the Antarctic winter.

SSA Sensor Calibration Best Practices

NASA Astrophysics Data System (ADS)

Johnson, T.

Best practices for calibrating orbit determination sensors in general and space situational awareness (SSA) sensors in particular are presented. These practices were developed over the last ten years within AGI and most recently applied to over 70 sensors in AGI's Commercial Space Operations Center (ComSpOC) and the US Air Force Space Command (AFSPC) Space Surveillance Network (SSN) to evaluate and configure new sensors and perform on-going system calibration. They are generally applicable to any SSA sensor and leverage some unique capabilities of an SSA estimation approach using an optimal sequential filter and smoother. Real world results are presented and analyzed.

Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

NASA Astrophysics Data System (ADS)

Forestieri, Sara D.; Cornwell, Gavin C.; Helgestad, Taylor M.; Moore, Kathryn A.; Lee, Christopher; Novak, Gordon A.; Sultana, Camille M.; Wang, Xiaofei; Bertram, Timothy H.; Prather, Kimberly A.; Cappa, Christopher D.

2016-07-01

The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative correlation with the SSA NR-OM volume fractions after the peak of the blooms (i.e., Chl a maxima); i.e., the GF(85 %) values generally decreased when the NR-OM volume fractions increased. The GF(85 %) vs. NR-OM volume fraction relationship was interpreted using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and used to estimate the GF(85 %) of the organic matter in the nascent SSA. The estimated pure NR-OM GF(85 %) values were 1.16 ± 0.09 and 1.23 ± 0.10 for the indoor and outdoor MARTS, respectively. These measurements demonstrate a clear relationship between SSA particle composition and the sensitivity of light scattering to variations in relative humidity. The implications of these observations to the direct climate effects of SSA particles are discussed.

Hydraulic and mechanical behavior of landfill clay liner containing SSA in contact with leachate.

PubMed

Zhang, Qian; Lu, Haijun; Liu, Junzhu; Wang, Weiwei; Zhang, Xiong

2018-05-01

Sewage sludge ash (SSA) produced by municipal sludge can be used as a modified additive for clay liner, and improves the working performance of landfill clay liner in contact with leachate. Under the action of landfill leachate, the permeability, shear strength, phase composition, and pore structure of the modified clay are investigated through the flexible wall permeability test, triaxial shear test, thermal gravimetric and differential thermal analysis, and low-temperature nitrogen adsorption test, respectively. The hydraulic conductivity of the modified clay containing 0-5% SSA is in the range of 3.94 × 10 -8 -1.16 × 10 -7  cm/s, and the pollutant concentration of the sample without SSA was higher than others. The shear strength of the modified clay is more than that of the traditional clay liner, the cohesion rate of modified clay increases from 32.5 to 199.91 kPa, and the internal friction angle decreases from 32.5° to 15.6°. Furthermore, the weight loss rates of the samples are 15.69%, 17.92%, 18.06%, and 20.68%, respectively, when the SSA content increases from 0% to 5%. The total pore volume and average pore diameter of the modified clay decrease with the increase in the SSA content, respectively. However, the specific area of the modified clay increases with the increase in the SSA content.

Validation study - on-road evaluation of the Cooperative Intersection Collision Avoidance System - Stop Sign Assist sign : (CICAS-SSA Report #5).

DOT National Transportation Integrated Search

2009-11-01

The CICAS-SSA sign is a roadside driver support system that is intended to improve gap rejection at rural stop-controlled intersections. The CICAS-SSA system tracks vehicle locations on a major roadway and then displays a message to a driver on the m...

20 CFR 435.25 - Revision of budget and program plans.

Code of Federal Regulations, 2014 CFR

2014-04-01

... section. (c) For nonconstruction awards, recipients must request prior approvals from SSA for one or more... with the prior approval of SSA. All pre-award costs are incurred at the recipient's risk (i.e., SSA is under no obligation to reimburse such costs if for any reason the recipient does not receive an award or...

20 CFR 435.25 - Revision of budget and program plans.

Code of Federal Regulations, 2013 CFR

2013-04-01

... section. (c) For nonconstruction awards, recipients must request prior approvals from SSA for one or more... with the prior approval of SSA. All pre-award costs are incurred at the recipient's risk (i.e., SSA is under no obligation to reimburse such costs if for any reason the recipient does not receive an award or...

20 CFR 435.25 - Revision of budget and program plans.

Code of Federal Regulations, 2012 CFR

2012-04-01

... section. (c) For nonconstruction awards, recipients must request prior approvals from SSA for one or more... with the prior approval of SSA. All pre-award costs are incurred at the recipient's risk (i.e., SSA is under no obligation to reimburse such costs if for any reason the recipient does not receive an award or...

20 CFR 435.25 - Revision of budget and program plans.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section. (c) For nonconstruction awards, recipients must request prior approvals from SSA for one or more... with the prior approval of SSA. All pre-award costs are incurred at the recipient's risk (i.e., SSA is under no obligation to reimburse such costs if for any reason the recipient does not receive an award or...

20 CFR 408.1235 - How does the State transfer funds to SSA to administer its recognition payment program?

Code of Federal Regulations, 2013 CFR

2013-04-01

... ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Federal Administration of State Recognition... end of each calendar month, SSA will provide the State with a statement showing, cumulatively, the... charged by SSA to administer such recognition payments; the State's total liability; and the end-of-month...

20 CFR 408.1235 - How does the State transfer funds to SSA to administer its recognition payment program?

Code of Federal Regulations, 2012 CFR

2012-04-01

... ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Federal Administration of State Recognition... end of each calendar month, SSA will provide the State with a statement showing, cumulatively, the... charged by SSA to administer such recognition payments; the State's total liability; and the end-of-month...

20 CFR 408.1235 - How does the State transfer funds to SSA to administer its recognition payment program?

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Federal Administration of State Recognition... end of each calendar month, SSA will provide the State with a statement showing, cumulatively, the... charged by SSA to administer such recognition payments; the State's total liability; and the end-of-month...

Education and Communities at the "Margins": The Contradictions of Western Education for Islamic Communities in Sub-Saharan Africa

ERIC Educational Resources Information Center

Mfum-Mensah, Obed

2017-01-01

This paper employs postcolonial framework to discuss the contradictions of promoting western education in Islamic communities in sub-Saharan Africa (SSA). Prior to colonization, Islamic education was an important socializing process that instilled strong Islamic identity in Islamic communities in SSA. European encounters in SSA and the…

20 CFR 422.505 - What types of applications and related forms are used to apply for retirement, survivors, and...

Code of Federal Regulations, 2010 CFR

2010-04-01

... applicants for certain reduced widow's or widower's benefits.) SSA-7156—Farm Self-Employment Questionnaire... covered under the Social Security Act.) SSA-7160—Employment Relationship Questionnaire. (For use by an individual and the alleged employer to determine the individual's employment status.) SSA-7163—Questionnaire...

75 FR 9012 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/U.S. Department of Health and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-26

... INFORMATION: A. General The Computer Matching and Privacy Protection Act of 1988 (Pub. L. 100-503), amended... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA-2009-0052] Privacy Act of 1974, as Amended; Computer Matching Program (SSA/ U.S. Department of Health and Human Services (HHS), Administration for...

76 FR 30749 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-26

... to the above e-mail address. 1. Marriage Certification--20 CFR 404.725--0960-0009. SSA uses Form SSA.... Statement Regarding Marriage--20 CFR 404.726--0960-0017. Section 216(h)(1)(A) of the Social Security Act... recognize marriages without a ceremony (i.e., common-law marriages). In such cases, SSA provides the same...

Sea Star Wasting Disease 2 Years On: What We know, What We Don't Yet Know, and What We are Doing Now to Understand the Disease

NASA Astrophysics Data System (ADS)

Hewson, I.

2016-02-01

Sea star wasting disease has affected over 20 species of asterozoa in waters from central Alaska to Baja California, causing extensive mortality and disappearance entirely from some areas. Combined viral, bacterial, eukaryotic microbial, and histological investigations identified the core nano- and micro-biome of sea stars, and elucidated that the Sea Star Associated Densovirus (SSaDV) was the most likely candidate microorganism involved in disease etiology. Direct challenge experiments using tissue homogenates from symptomatic animals injected into asymptomatic individuals revealed that the disease is caused by a virus-sized entity. However, there remains much to be learned about the disease, especially how disease symptoms are generated by SSaDV, how the virus is transmitted between infected and uninfected animals, and why SSaDV may cause disease recently. We performed inoculation trials on SSaDV-naïve sea stars collected from a geographically distant population away from disease-affected areas, and observed viral, bacterial, archaeal, and host transcriptomic responses over time. We also performed surveys of SSaDV in juveniles and larval plankton, as well as the environmental distribution and stability of SSaDV in key regions where SSWD has all but wiped out adults. Our results suggest that SSaDV must move around either on particles or by direct contact between animals, since decay rates exceed reasonable transmission times based on sea star abundance. Global surveys of sea star-associated viruses also elucidate that SSaDV may have been present in populations of sea stars from Hong Kong around the same time of the 2013-2015 epidemic.

Sensory-specific appetite is affected by actively smelled food odors and remains stable over time in normal-weight women.

PubMed

Ramaekers, Mariëlle G; Boesveldt, Sanne; Gort, Gerrit; Lakemond, Catriona M M; van Boekel, Martinus A J S; Luning, Pieternel A

2014-08-01

Understanding overconsumption starts with knowledge of how separate factors influence our eating behavior. Food cues such as food odors are known for their effect on general appetite and sensory-specific appetite (SSA). Active sniffing rather than passive exposure may induce satiation over time. The objective of this study was to investigate how actively sniffing banana odors affects general appetite, SSA, and subsequent food intake. In a crossover study, 61 women actively smelled cups containing natural banana, artificial banana odor, or water (no odor) for 10 min. Treatment order was randomly assigned as much as possible. General appetite and SSA were monitored by using 100-mm visual analog scales during the 10 min of active sniffing, followed by ad libitum intake of banana milkshake. Results showed that SSA was consistently high (+12 mm) during actively sniffing natural or artificial banana odors, with no decrease in SSA over time. Sniffing both banana odors increased the appetite for banana (+11 mm) and other sweet products (+4 mm), whereas the appetite for savory products decreased by 7 mm (all P < 0.01) compared with no odor. Actively sniffing banana odor did not significantly influence food intake (P = 0.68) or general appetite scores (P = 0.06). In conclusion, SSA scores during active sniffing were identical to the SSA found in a similar study that used passive smelling, suggesting that SSA is independent of the manner of sniffing and exposure time. Moreover, sweet/savory categorization may suggest that food odors communicate information about the nutrient composition of their associated foods. These data clearly show the appetizing effects of food odors. © 2014 American Society for Nutrition.

Findings from the UK and Canadian Space Situational Awareness (SSA) Experimentation during the Relocation of SKYNET 5A Satellite

NASA Astrophysics Data System (ADS)

Ash, A.; Scott, L.; Feline, W.

2016-09-01

This paper describes the planning, execution, analysis and lessons identified from a collaborative Space Situational Awareness (SSA) experiment to observe the SKYNET 5A satellite during a series of orbital maneuvers that occurred in the summer of 2015. In March 2015 Airbus Defence and Space (Airbus DS) announced its intention to relocate the SKYNET 5A satellite from the Atlantic to the Asia Pacific region to increase its global coverage; this provided an opportunity to observe this high value asset to explore the challenges and technical solutions related to deep space SSA. Within the UK the Defence Science and Technology Laboratory (Dstl, part of the UK Ministry of Defence) were established as the lead agency to plan the observation campaign utilising operational and emerging experimental SSA capabilities. The campaign was then expanded to involve Canada, the United States and Australia under the auspices of the Combined Space Operations (CSpO) Memorandum of Understanding (MOU) to further explore the coordination of observations between operational systems and potential fusion of data collected using experimental SSA assets. The focus for this paper is the collaborative work between Dstl and Defence Research and Development Canada (DRDC) that featured a period of experimentation to explore methods that enable cross cueing between ground-based and space-based SSA sensors, namely the UK Starbrook facility (located on the island of Cyprus), and NEOSSat/ Sapphire space surveillance satellites located in low-Earth orbit. A number of conclusions and lessons are identified in this paper that seek to inform the wider SSA community on the challenges, potential solutions and benefits of operating a distributed SSA architecture such as the one utilized during this experiment.

Molecular features of colorectal polyps presenting Kudo’s type II mucosal crypt pattern: are they based on the same mechanism of tumorigenesis?

PubMed Central

Shinmura, Kensuke; Konishi, Kazuo; Yamochi, Toshiko; Kubota, Yutaro; Yano, Yuichiro; Katagiri, Atsushi; Muramoto, Takashi; Kihara, Toshihiro; Tojo, Masayuki; Konda, Kenichi; Tagawa, Teppei; Yanagisawa, Fumito; Kogo, Mari; Makino, Reiko; Takimoto, Masafumi; Yoshida, Hitoshi

2014-01-01

Background and study aims: The molecular features of serrated polyps (SPs) with hyperplastic crypt pattern, also called Kudo’s type II observed by chromoendoscopy, were evaluated. Methods: The clinicopathological and molecular features of 114 SPs with a hyperplastic pit pattern detected under chromoendoscopy (five dysplastic SPs, 63 sessile serrated adenoma/polyps (SSA/Ps), 36 microvesicular hyperplastic polyps (MVHPs), and 10 goblet cell-rich hyperplastic polyps (GCHPs)) were examined. The frequency of KRAS and BRAF mutations and CpG island methylator phenotype (CIMP) were investigated. Results: Dysplastic SPs and SSA/Ps were frequently located in the proximal colon compared to others (SSA/Ps vs. MVHPs or GCHPs, P < 0.0001). No significant difference was found in the frequency of BRAF mutation among SPs apart from GCHP (60 % for dysplastic SPs, 44 % for SSA/Ps, 47 % for MVHPs, and 0 % for GCHPs). The frequency of CIMP was higher in dysplastic SPs or SSA/Ps than in MVHPs or GCHPs (60 % for dysplastic SPs, 56 % for SSA/Ps, 32 % for MVHPs, and 10 % for GCHPs) (SSA/Ps vs. GCHP, P = 0.0068). When serrated neoplasias (SNs) and MVHPs were classified into proximal and distal lesions, the frequency of CIMP was significantly higher in the proximal compared to the distal SNs (64 % vs. 11 %, P = 0.0032). Finally, multivariate analysis showed that proximal location and BRAF mutation were significantly associated with an increased risk of CIMP. Conclusions: Distinct molecular features were observed between proximal and distal SPs with hyperplastic crypt pattern. Proximal MVHPs may develop more frequently through SSA/Ps to CIMP cancers than distal MVHPs. PMID:26134964

Molecular features of colorectal polyps presenting Kudo's type II mucosal crypt pattern: are they based on the same mechanism of tumorigenesis?

PubMed

Shinmura, Kensuke; Konishi, Kazuo; Yamochi, Toshiko; Kubota, Yutaro; Yano, Yuichiro; Katagiri, Atsushi; Muramoto, Takashi; Kihara, Toshihiro; Tojo, Masayuki; Konda, Kenichi; Tagawa, Teppei; Yanagisawa, Fumito; Kogo, Mari; Makino, Reiko; Takimoto, Masafumi; Yoshida, Hitoshi

2014-09-01

The molecular features of serrated polyps (SPs) with hyperplastic crypt pattern, also called Kudo's type II observed by chromoendoscopy, were evaluated. The clinicopathological and molecular features of 114 SPs with a hyperplastic pit pattern detected under chromoendoscopy (five dysplastic SPs, 63 sessile serrated adenoma/polyps (SSA/Ps), 36 microvesicular hyperplastic polyps (MVHPs), and 10 goblet cell-rich hyperplastic polyps (GCHPs)) were examined. The frequency of KRAS and BRAF mutations and CpG island methylator phenotype (CIMP) were investigated. Dysplastic SPs and SSA/Ps were frequently located in the proximal colon compared to others (SSA/Ps vs. MVHPs or GCHPs, P < 0.0001). No significant difference was found in the frequency of BRAF mutation among SPs apart from GCHP (60 % for dysplastic SPs, 44 % for SSA/Ps, 47 % for MVHPs, and 0 % for GCHPs). The frequency of CIMP was higher in dysplastic SPs or SSA/Ps than in MVHPs or GCHPs (60 % for dysplastic SPs, 56 % for SSA/Ps, 32 % for MVHPs, and 10 % for GCHPs) (SSA/Ps vs. GCHP, P = 0.0068). When serrated neoplasias (SNs) and MVHPs were classified into proximal and distal lesions, the frequency of CIMP was significantly higher in the proximal compared to the distal SNs (64 % vs. 11 %, P = 0.0032). Finally, multivariate analysis showed that proximal location and BRAF mutation were significantly associated with an increased risk of CIMP. Distinct molecular features were observed between proximal and distal SPs with hyperplastic crypt pattern. Proximal MVHPs may develop more frequently through SSA/Ps to CIMP cancers than distal MVHPs.

The specificity of stimulus-specific adaptation in human auditory cortex increases with repeated exposure to the adapting stimulus.

PubMed

Briley, Paul M; Krumbholz, Katrin

2013-12-01

The neural response to a sensory stimulus tends to be more strongly reduced when the stimulus is preceded by the same, rather than a different, stimulus. This stimulus-specific adaptation (SSA) is ubiquitous across the senses. In hearing, SSA has been suggested to play a role in change detection as indexed by the mismatch negativity. This study sought to test whether SSA, measured in human auditory cortex, is caused by neural fatigue (reduction in neural responsiveness) or by sharpening of neural tuning to the adapting stimulus. For that, we measured event-related cortical potentials to pairs of pure tones with varying frequency separation and stimulus onset asynchrony (SOA). This enabled us to examine the relationship between the degree of specificity of adaptation as a function of frequency separation and the rate of decay of adaptation with increasing SOA. Using simulations of tonotopic neuron populations, we demonstrate that the fatigue model predicts independence of adaptation specificity and decay rate, whereas the sharpening model predicts interdependence. The data showed independence and thus supported the fatigue model. In a second experiment, we measured adaptation specificity after multiple presentations of the adapting stimulus. The multiple adapters produced more adaptation overall, but the effect was more specific to the adapting frequency. Within the context of the fatigue model, the observed increase in adaptation specificity could be explained by assuming a 2.5-fold increase in neural frequency selectivity. We discuss possible bottom-up and top-down mechanisms of this effect.

Assessment of seasonal soil moisture forecasts over Southern South America with emphasis on dry and wet events

NASA Astrophysics Data System (ADS)

Spennemann, Pablo; Rivera, Juan Antonio; Osman, Marisol; Saulo, Celeste; Penalba, Olga

2017-04-01

The importance of forecasting extreme wet and dry conditions from weeks to months in advance relies on the need to prevent considerable socio-economic losses, mainly in regions of large populations and where agriculture is a key value for the economies, like Southern South America (SSA). Therefore, to improve the understanding of the performance and uncertainties of seasonal soil moisture and precipitation forecasts over SSA, this study aims to: 1) perform a general assessment of the Climate Forecast System version-2 (CFSv2) soil moisture and precipitation forecasts; and 2) evaluate the CFSv2 ability to represent an extreme drought event merging observations with forecasted Standardized Precipitation Index (SPI) and the Standardized Soil Moisture Anomalies (SSMA) based on GLDAS-2.0 simulations. Results show that both SPI and SSMA forecast skill are regionally and seasonally dependent. In general a fast degradation of the forecasts skill is observed as the lead time increases with no significant metrics for forecast lead times longer than 2 months. Based on the assessment of the 2008-2009 extreme drought event it is evident that the CFSv2 forecasts have limitations regarding the identification of drought onset, duration, severity and demise, considering both meteorological (SPI) and agricultural (SSMA) drought conditions. These results have some implications upon the use of seasonal forecasts to assist agricultural practices in SSA, given that forecast skill is still too low to be useful for lead times longer than 2 months.

Resonance assignments for the substrate binding domain of Hsp70 chaperone Ssa1 from Saccharomyces cerevisiae.

PubMed

Hu, Wanhui; Wu, Huiwen; Zhang, Hong; Gong, Weibin; Perrett, Sarah

2015-10-01

Hsp70 chaperone proteins play crucial roles in the cell. Extensive structural and functional studies have been performed for bacterial and mammalian Hsp70s. Ssa1 from Saccharomyces cerevisiae is a member of the Hsp70 family. In vivo and biochemical studies on Ssa1 have revealed that it regulates prion propagation and the cell cycle. However, no structural data has been obtained for Ssa1 up to now. Here we report the almost complete (96 %) (1)H, (13)C, (15)N backbone and side chain NMR assignment of the 18.8 kDa Ssa1 substrate binding domain. The construct includes residues 382-554, which corresponds to the entire substrate binding domain and two following α-helices in homologous structures. The secondary structure predicted from the assigned chemical shifts is consistent with that of homologous Hsp70 substrate binding domains.

Spike shape analysis of electromyography for parkinsonian tremor evaluation.

PubMed

Marusiak, Jarosław; Andrzejewska, Renata; Świercz, Dominika; Kisiel-Sajewicz, Katarzyna; Jaskólska, Anna; Jaskólski, Artur

2015-12-01

Standard electromyography (EMG) parameters have limited utility for evaluation of Parkinson disease (PD) tremor. Spike shape analysis (SSA) EMG parameters are more sensitive than standard EMG parameters for studying motor control mechanisms in healthy subjects. SSA of EMG has not been used to assess parkinsonian tremor. This study assessed the utility of SSA and standard time and frequency analysis for electromyographic evaluation of PD-related resting tremor. We analyzed 1-s periods of EMG recordings to detect nontremor and tremor signals in relaxed biceps brachii muscle of seven mild to moderate PD patients. SSA revealed higher mean spike amplitude, duration, and slope and lower mean spike frequency in tremor signals than in nontremor signals. Standard EMG parameters (root mean square, median, and mean frequency) did not show differences between the tremor and nontremor signals. SSA of EMG data is a sensitive method for parkinsonian tremor evaluation. © 2015 Wiley Periodicals, Inc.

Projected climate change impacts and short term predictions on staple crops in Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Mereu, V.; Spano, D.; Gallo, A.; Carboni, G.

2013-12-01

Agriculture in Sub-Saharan Africa (SSA) drives the economy of many African countries and it is mainly rain-fed agriculture used for subsistence. Increasing temperatures, changed precipitation patterns and more frequent droughts may lead to a substantial decrease of crop yields. The projected impacts of future climate change on agriculture are expected to be significant and extensive in the SSA due to the shortening of the growing seasons and the increasing of water-stress risk. Differences in Agro-Ecological Zones and geographical characteristics of SSA influence the diverse impacts of climate change, which can greatly differ across the continent and within countries. The vulnerability of African Countries to climate change is aggravated by the low adaptive capacity of the continent, due to the increasing of its population, the widespread poverty, and other social factors. In this contest, the assessment of climate change impact on agricultural sector has a particular interest to stakeholder and policy makers, in order to identify specific agricultural sectors and Agro-Ecological Zones that could be more vulnerable to changes in climatic conditions and to develop the most appropriate policies to cope with these threats. For these reasons, the evaluation of climate change impacts for key crops in SSA was made exploring climate uncertainty and focusing on short period monitoring, which is particularly useful for food security and risk management analysis. The DSSAT-CSM (Decision Support System for Agrotechnology Transfer - Cropping System Model) software, version 4.5 was used for the analysis. Crop simulation models included in DSSAT-CSM are tools that allow to simulate physiological process of crop growth, development and production, by combining genetic crop characteristics and environmental (soil and weather) conditions. For each selected crop, the models were used, after a parameterization phase, to evaluate climate change impacts on crop phenology and production. Multiple combinations of soils and climate conditions, crop management and varieties were considered for the different Agro-Ecological Zones. The climate impact was assessed using future climate prediction, statistically and/or dynamically downscaled, for specific areas. Direct and indirect effects of different CO2 concentrations projected for the future periods were separately explored to estimate their effects on crops. Several adaptation strategies (e.g., introduction of full irrigation, shift of the ordinary sowing/planting date, changes in the ordinary fertilization management) were also evaluated with the aim to reduce the negative impact of climate change on crop production. The results of the study, analyzed at local, AEZ and country level, will be discussed.

77 FR 59690 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-28

... uses form SSA-7011-F4 to document the alleged wages. Specifically, the agency uses the form to resolve... benefits. We only send Form SSA-7011-F4 to employers if we are unable to locate the earnings information in... (minutes) (hours) SSA-7011-F4 462,000 1 20 154,000 2. Request for Deceased Individual's Social Security...

77 FR 76160 - Agency Information Collection Activities: Proposed Request and Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-26

... packages requiring clearance by the Office of Management and Budget (OMB) in compliance with Public Law 104... (GPO). SSA uses the information from Form SSA-760-F4 to determine if the parent of a deceased worker or... response annual burden respondents response (minutes) (hours) SSA-760-F4 18,000 1 15 4,500 2. Physician's...

78 FR 11815 - Creation of a New Computer Matching Program That Will Expire on August 13, 2014

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-20

... Applications, SSA/OEEAS, 60-0058, full text published at 71 FR 1815 (January 11, 2006); the Master Beneficiary Record, SSA/ ORSIS 60-0090, full text published at 71 FR 1826 (January 11, 2006); and Supplemental Security Income and Special Veterans Benefits SSA/ ODSSIS, 60-0103, full text published at 71 FR 1826...

Sociocultural factors and breast cancer in sub-Saharan Africa: implications for diagnosis and management.

PubMed

Tetteh, Dinah A; Faulkner, Sandra L

2016-01-01

The incidence of breast cancer is on the rise in sub-Saharan Africa (SSA) and efforts at early diagnosis have not been very successful because the public has scant knowledge about the disease, a large percentage of breast cancer cases are diagnosed late and mainly rural SSA women's practice of breast self-examination is poor. In this paper, we argue that an examination of the social and cultural contexts of SSA that influence breast cancer diagnosis and management in the region is needed. We discuss the implications of sociocultural factors, such as gender roles and spirituality, on breast cancer diagnosis and management in SSA.

Saponins extracted from by-product of Asparagus officinalis L. suppress tumour cell migration and invasion through targeting Rho GTPase signalling pathway.

PubMed

Wang, Jieqiong; Liu, Yali; Zhao, Jingjing; Zhang, Wen; Pang, Xiufeng

2013-04-01

The inedible bottom part (~30-40%) of asparagus (Asparagus officinalis L.) spears is usually discarded as waste. However, since this by-product has been reported to be rich in many bioactive phytochemicals, it might be utilisable as a supplement in foods or natural drugs for its therapeutic effects. In this study it was identifed that saponins from old stems of asparagus (SSA) exerted potential inhibitory activity on tumour growth and metastasis. SSA suppressed cell viability of breast, colon and pancreatic cancers in a concentration-dependent manner, with half-maximum inhibitory concentrations ranging from 809.42 to 1829.96 µg mL(-1). However, SSA was more functional in blocking cell migration and invasion as compared with its cytotoxic effect, with an effective inhibitory concentration of 400 µg mL(-1). A mechanistic study showed that SSA markedly increased the activities of Cdc42 and Rac1 and decreased the activity of RhoA in cancer cells. SSA inhibits tumour cell motility through modulating the Rho GTPase signalling pathway, suggesting a promising use of SSA as a supplement in healthcare foods and natural drugs for cancer prevention and treatment. © 2012 Society of Chemical Industry.

Do the same risk and protective factors influence aggression toward partners and same-sex others?

PubMed

Bates, Elizabeth A; Archer, John; Graham-Kevan, Nicola

2017-04-01

The current studies examined whether several risk and protective factors operate similarly for intimate partner violence (IPV) and same-sex aggression (SSA) in the same sample, and to assess whether they show similar associations for men and women. Study 1 (N = 345) tested perceived benefits and costs, and instrumental and expressive beliefs about aggression: perceived costs predicted IPV and SSA for both men and women. Expressive beliefs predicted IPV (more strongly for women), and instrumental beliefs predicted SSA. Study 2 (N = 395) investigated self-control, anxiety and empathy, finding that self-control strongly predicted both types of aggression in both sexes. Study 3 (N = 364) found that primary psychopathy (involving lack of anxiety) was associated with IPV for men and SSA in both sexes, whereas secondary psychopathy (involving lack of self-control) was associated with IPV and SSA in both sexes. Overall there were both similarities and differences in the risk factors associated with IPV and SSA, and for men and women. The implications of the findings for theoretical debates about the study of IPV are discussed. Aggr. Behav. 43:163-175, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The Agrobacterium tumefaciens Transcription Factor BlcR Is Regulated via Oligomerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Yi; Fiscus, Valena; Meng, Wuyi

2012-02-08

The Agrobacterium tumefaciens BlcR is a member of the emerging isocitrate lyase transcription regulators that negatively regulates metabolism of {gamma}-butyrolactone, and its repressing function is relieved by succinate semialdehyde (SSA). Our crystal structure showed that BlcR folded into the DNA- and SSA-binding domains and dimerized via the DNA-binding domains. Mutational analysis identified residues, including Phe{sup 147}, that are important for SSA association; BlcR{sup F147A} existed as tetramer. Two BlcR dimers bound to target DNA and in a cooperative manner, and the distance between the two BlcR-binding sequences in DNA was critical for BlcR-DNA association. Tetrameric BlcR{sup F147A} retained DNA bindingmore » activity, and importantly, this activity was not affected by the distance separating the BlcR-binding sequences in DNA. SSA did not dissociate tetrameric BlcR{sup F147A} or BlcR{sup F147A}-DNA. As well as in the SSA-binding site, Phe{sup 147} is located in a structurally flexible loop that may be involved in BlcR oligomerization. We propose that SSA regulates BlcR DNA-binding function via oligomerization.« less

Enabling GEODSS for Space Situational Awareness (SSA)

NASA Astrophysics Data System (ADS)

Wootton, S.

2016-09-01

The Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) System has been in operation since the mid-1980's. While GEODSS has been the Space Surveillance Network's (SSN's) workhorse in terms of deep space surveillance, it has not undergone a significant modernization since the 1990's. This means GEODSS continues to operate under a mostly obsolete, legacy data processing baseline. The System Program Office (SPO) responsible for GEODSS, SMC/SYGO, has a number of advanced Space Situational Awareness (SSA)-related efforts in progress, in the form of innovative optical capabilities, data processing algorithms, and hardware upgrades. Each of these efforts is in various stages of evaluation and acquisition. These advanced capabilities rely upon a modern computing environment in which to integrate, but GEODSS does not have one—yet. The SPO is also executing a Service Life Extension Program (SLEP) to modernize the various subsystems within GEODSS, along with a parallel effort to implement a complete, modern software re-architecture. The goal is to use a modern, service-based architecture to provide expedient integration as well as easier and more sustainable expansion. This presentation will describe these modernization efforts in more detail and discuss how adopting such modern paradigms and practices will help ensure the GEODSS system remains relevant and sustainable far beyond 2027.

The Chemical Composition and Mixing State of Sea Spray Aerosol and Organic Aerosol in the Winter-Spring Arctic

NASA Astrophysics Data System (ADS)

Kirpes, R.; Bondy, A. L.; Bonanno, D.; Moffet, R.; Wang, B.; Laskin, A.; Ault, A. P.; Pratt, K.

2016-12-01

The Arctic region is undergoing rapid transformations and loss of sea ice due to climate change. With increased sea ice fracturing resulting in greater open ocean surface, winter emissions of sea spray aerosol (SSA) are expected to be increasing. Additionally, during the winter-spring transition, Arctic haze contributes to the Arctic aerosol budget. The magnitude of aerosol climate effects depends on the aerosol composition and mixing state (distribution of chemical species within and between particles). However, few studies of aerosol chemistry have been conducted in the winter Arctic, despite it being a time when aerosol impacts on clouds are expected to be significant. To study aerosol composition and mixing state in the winter Arctic, atmospheric particles were collected near Barrow, Alaska in January and February 2014 for off-line individual particle chemical analysis. SSA was the most prevalent particle type observed. Sulfate and nitrate were observed to be internally mixed with SSA and organic aerosol. Greater than 98% of observed SSA particles contained organic content, with 15-35% organic volume fraction on average for individual particles. The SSA organic compounds consisted of carbohydrates, lipids, and fatty acids found in the seawater surface microlayer. SSA was determined to be emitted from open leads, while transported sulfate and nitrate contributed to aging of SSA and organic aerosol. Determining the aerosol chemical composition and mixing state in the winter Arctic will further the understanding of how individual aerosol particles impact climate through radiative effects and cloud formation.

Stimulus-specific adaptation and deviance detection in the inferior colliculus

PubMed Central

Ayala, Yaneri A.; Malmierca, Manuel S.

2013-01-01

Deviancy detection in the continuous flow of sensory information into the central nervous system is of vital importance for animals. The task requires neuronal mechanisms that allow for an efficient representation of the environment by removing statistically redundant signals. Recently, the neuronal principles of auditory deviance detection have been approached by studying the phenomenon of stimulus-specific adaptation (SSA). SSA is a reduction in the responsiveness of a neuron to a common or repetitive sound while the neuron remains highly sensitive to rare sounds (Ulanovsky et al., 2003). This phenomenon could enhance the saliency of unexpected, deviant stimuli against a background of repetitive signals. SSA shares many similarities with the evoked potential known as the “mismatch negativity,” (MMN) and it has been linked to cognitive process such as auditory memory and scene analysis (Winkler et al., 2009) as well as to behavioral habituation (Netser et al., 2011). Neurons exhibiting SSA can be found at several levels of the auditory pathway, from the inferior colliculus (IC) up to the auditory cortex (AC). In this review, we offer an account of the state-of-the art of SSA studies in the IC with the aim of contributing to the growing interest in the single-neuron electrophysiology of auditory deviance detection. The dependence of neuronal SSA on various stimulus features, e.g., probability of the deviant stimulus and repetition rate, and the roles of the AC and inhibition in shaping SSA at the level of the IC are addressed. PMID:23335883

Novel Sfp1 Transcriptional Regulation of Saccharomyces cerevisiae Gene Expression Changes During Spaceflight

NASA Astrophysics Data System (ADS)

Coleman, Chasity B.; Allen, Patricia L.; Rupert, Mark; Goulart, Carla; Hoehn, Alexander; Stodieck, Louis S.; Hammond, Timothy G.

2008-12-01

This study identifies transcriptional regulation of stress response element (STRE) genes in space in the model eukaryotic organism, Saccharomyces cerevisiae. To determine transcription-factor dependence, gene expression changes in space were examined in strains bearing green fluorescent protein tagged (GFP-tagged) reporters for YIL052C (Sfp1 dependent with stress), YST-2 (Sfp1/Rap1 dependent with stress), or SSA4 (Msn4 dependent with stress), along with strains of SSA4-GFP and YIL052C-GFP with individual deletions of the Msn4 or Sfp1. When compared to parallel ground controls, spaceflight induces significant gene expression changes in SSA4 (35% decrease) and YIL052C (45% decrease), while expression of YST-2 (0.08% decrease) did not change. In space, deletion of Sfp1 reversed the SSA4 gene expression effect (0.00% change), but Msn4 deletion yielded a similar decrease in SSA4 expression (34% change), which indicates that SSA4 gene expression is dependent on the Sfp1 transcription factor in space, unlike other stresses. For YIL052C, deletion of Sfp1 reversed the effect (0.01% change), and the Msn4 deletion maintained the decrease in expression (30% change), which indicates that expression of YIL052C is also dependent on Sfp1 in space. Spaceflight has selective and specific effects on SSA4 and YIL052C gene expression, indicated by novel dependence on Sfp1.

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

NASA Astrophysics Data System (ADS)

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-07-01

The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer. In contrast, jet drops formed from the base of bursting bubbles are postulated to mainly produce larger supermicrometer particles from bulk seawater, which comprises largely salts and water-soluble organic species. However, here we demonstrate that jet drops produce up to 43% of total submicrometer SSA number concentrations, and that the fraction of SSA produced by jet drops can be modulated by marine biological activity. We show that the chemical composition, organic volume fraction, and ice nucleating ability of submicrometer particles from jet drops differ from those formed from film drops. Thus, the chemical composition of a substantial fraction of submicrometer particles will not be controlled by the composition of the sea surface microlayer, a major assumption in previous studies. This finding has significant ramifications for understanding the factors controlling the mixing state of submicrometer SSA particles and must be taken into consideration when predicting SSA impacts on clouds and climate.

Global analysis of pre-mRNA subcellular localization following splicing inhibition by spliceostatin A

PubMed Central

Yoshimoto, Rei; Kaida, Daisuke; Furuno, Masaaki; Burroughs, A. Maxwell; Noma, Shohei; Suzuki, Harukazu; Kawamura, Yumi; Hayashizaki, Yoshihide; Mayeda, Akila; Yoshida, Minoru

2017-01-01

Spliceostatin A (SSA) is a methyl ketal derivative of FR901464, a potent antitumor compound isolated from a culture broth of Pseudomonas sp. no. 2663. These compounds selectively bind to the essential spliceosome component SF3b, a subcomplex of the U2 snRNP, to inhibit pre-mRNA splicing. However, the mechanism of SSA's antitumor activity is unknown. It is noteworthy that SSA causes accumulation of a truncated form of the CDK inhibitor protein p27 translated from CDKN1B pre-mRNA, which is involved in SSA-induced cell-cycle arrest. However, it is still unclear whether pre-mRNAs are uniformly exported from the nucleus following SSA treatment. We performed RNA-seq analysis on nuclear and cytoplasmic fractions of SSA-treated cells. Our statistical analyses showed that intron retention is the major consequence of SSA treatment, and a small number of intron-containing pre-mRNAs leak into the cytoplasm. Using a series of reporter plasmids to investigate the roles of intronic sequences in the pre-mRNA leakage, we showed that the strength of the 5′ splice site affects pre-mRNA leakage. Additionally, we found that the level of pre-mRNA leakage is related to transcript length. These results suggest that the strength of the 5′ splice site and the length of the transcripts are determinants of the pre-mRNA leakage induced by SF3b inhibitors. PMID:27754875

BOREAS TF-11 SSA-Fen Leaf Gas Exchange Data

NASA Technical Reports Server (NTRS)

Arkebauer, Timothy J.; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

2000-01-01

The BOREAS TF-11 team gathered a variety of data to complement its tower flux measurements collected at the SSA-Fen site. This data set contains single-leaf gas exchange data from the SSA-Fen site during 1994 and 1995. These leaf gas exchange properties were measured for the dominant vascular plants using portable gas exchange systems. The data are stored in tabular ASCII files.

U.S. Counterterrorism in Sub-Saharan Africa: Understanding Costs, Cultures, and Conflicts

DTIC Science & Technology

2008-09-01

counterterrorism in SSA. Vast and diverse, SSA is divided subregionally into East, West, and Southern Africa so as to highlight the different ...divided into East, West, and Southern Africa subregions so as to highlight the different geographies, histories, threats, and perceptions. Section...subregional approach. It divides SSA into East, West, and Southern Africa to highlight the different geogra- phies, histories, threats, and perceptions

The Potsdam Parallel Ice Sheet Model (PISM-PIK) - Part 1: Model description

NASA Astrophysics Data System (ADS)

Winkelmann, R.; Martin, M. A.; Haseloff, M.; Albrecht, T.; Bueler, E.; Khroulev, C.; Levermann, A.

2011-09-01

We present the Potsdam Parallel Ice Sheet Model (PISM-PIK), developed at the Potsdam Institute for Climate Impact Research to be used for simulations of large-scale ice sheet-shelf systems. It is derived from the Parallel Ice Sheet Model (Bueler and Brown, 2009). Velocities are calculated by superposition of two shallow stress balance approximations within the entire ice covered region: the shallow ice approximation (SIA) is dominant in grounded regions and accounts for shear deformation parallel to the geoid. The plug-flow type shallow shelf approximation (SSA) dominates the velocity field in ice shelf regions and serves as a basal sliding velocity in grounded regions. Ice streams can be identified diagnostically as regions with a significant contribution of membrane stresses to the local momentum balance. All lateral boundaries in PISM-PIK are free to evolve, including the grounding line and ice fronts. Ice shelf margins in particular are modeled using Neumann boundary conditions for the SSA equations, reflecting a hydrostatic stress imbalance along the vertical calving face. The ice front position is modeled using a subgrid-scale representation of calving front motion (Albrecht et al., 2011) and a physically-motivated calving law based on horizontal spreading rates. The model is tested in experiments from the Marine Ice Sheet Model Intercomparison Project (MISMIP). A dynamic equilibrium simulation of Antarctica under present-day conditions is presented in Martin et al. (2011).

Drought vulnerability assessment of maize in Sub-Saharan Africa: Insights from physical and social perspectives

NASA Astrophysics Data System (ADS)

Kamali, Bahareh; Abbaspour, Karim C.; Wehrli, Bernhard; Yang, Hong

2018-03-01

Drought as a slow-onset phenomenon inflicts important losses to agriculture where the degree of vulnerability depends not only on physical variables such as precipitation and temperature, but also on societal preparedness. While the scopes of physical and social vulnerability are very different in nature, studies distinguishing these two aspects have been lacking. In this study we address the physical and social aspects of drought vulnerability of maize (CDVIphy and CDVIsoc) in Sub-Saharan Africa (SSA). To quantify vulnerability, we applied a probabilistic framework combining a Drought Exposure Index (DEI) with a physical or social Crop Failure Index, CFIphy or CFIsoc, respectively. DEI was derived from the exceedance probability of precipitation. Maize yields, simulated using the Environmental Policy Integrated Climate (EPIC) model, were used to build CFIphy, whereas the residual of simulated and FAO recorded yields were used to construct CFIsoc. The results showed that southern and partially central Africa are more vulnerable to physical drought as compared to other regions. Central and western Africa, however, are socially highly vulnerable. Comparison of CDVIphy and CDVIsoc revealed that societal factors cause more vulnerability than physical variables in almost all SSA countries except Nigeria and South Africa. We conclude that quantification of both drought vulnerabilities help a better characterization of droughts and identify regions where more investments in drought preparedness are required.

A Comparison of JPDA and Belief Propagation for Data Association in SSA

NASA Astrophysics Data System (ADS)

Rutten, M.; Williams, J.; Gordon, N.; Jah, M.; Baldwin, J.; Stauch, J.

2014-09-01

The process of initial orbit determination, or catalogue maintenance, using a set of unlabeled observations requires a method of choosing which observation was due to which object. Realities of imperfect sensors mean that the association must be made in the presence of both missed detections and false alarms. Data association is not only essential to processing observations it can also be one of the most significant computational bottlenecks. The constrained admissible region multiple hypothesis filter (CAR-MHF) is an algorithm for initial orbit determination using short-arc observations of space objects. CAR-MHF has used joint probabilistic data association (JPDA), a well-established approach to multi-target data association. A recent development in the target tracking literature is the use of graphical models to formulate data association problems. Using an approximate inference algorithm, belief propagation (BP), on the graphical model results in an algorithm this is both computationally efficient and accurate. This paper compares CAR-MHF using JPDA and CAR-MHF using BP for the problem of initial orbit determination on a set of deep-space objects. The results of the analysis will show that by using the BP algorithm there are significant gains in computational load without any statistically significant loss in overall performance of the orbit determination.

Evaluation of magnifying colonoscopy in the diagnosis of serrated polyps.

PubMed

Ishigooka, Shinya; Nomoto, Masahito; Obinata, Nobuyuki; Oishi, Yoshichika; Sato, Yoshinori; Nakatsu, Satoko; Suzuki, Midori; Ikeda, Yoshiko; Maehata, Tadateru; Kimura, Tomoaki; Watanabe, Yoshiyuki; Nakajima, Takashi; Yamano, Hiro-o; Yasuda, Hiroshi; Itoh, Fumio

2012-08-28

To elucidate the colonoscopic features of serrated lesions of the colorectum using magnifying colonoscopy. Broad division of serrated lesions of the colorectum into hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenomas/polyps (SSA/Ps) has been proposed on the basis of recent molecular biological studies. However, few reports have examined the colonoscopic features of these divisions, including magnified colonoscopic findings. This study examined 118 lesions excised in our hospital as suspected serrated lesions after magnified observation between January 2008 and September 2011. Patient characteristics (sex, age), conventional colonoscopic findings (location, size, morphology, color, mucin) and magnified colonoscopic findings (pit pattern diagnosis) were interpreted by five colonoscopists with experience in over 1000 colonoscopies, and were compared with histopathological diagnoses. The pit patterns were categorized according to Kudo's classification, but a more detailed investigation was also performed using the subclassification [type II-Open (type II-O), type II-Long (type II-L), or type IV-Serrated (type IV-S)] proposed by Kimura T and Yamano H. Lesions comprised 23 HPs (23/118: 19.5%), 39 TSAs (39/118: 33.1%: with cancer in one case), 50 SSA/Ps (50/118: 42.4%: complicated with cancer in three cases), and six others (6/118: 5.1%). We excluded six others, including three regular adenomas, one hamartoma, one inflammatory polyp, and one juvenile polyp for further analysis. Conventional colonoscopy showed that SSA/Ps were characterized as larger in diameter than TSAs and HPs (SSA/P vs HP, 13.62 ± 8.62 mm vs 7.74 ± 3.24 mm, P < 0.001; SSA/Ps vs TSA, 13.62 ± 8.62 mm vs 9.89 ± 5.73 mm, P < 0.01); common in the right side of the colon [HPs, 30.4% (7/23): TSAs, 20.5% (8/39): SSA/P, 84.0% (42/50), P < 0.001]; flat-elevated lesion [HPs, 30.4% (7/23): TSAs, 5.1% (2/39): SSA/Ps, 90.0% (45/50), P < 0.001]; normal-colored or pale imucosa [HPs, 34.8% (8/23): TSAs, 10.3% (4/39): SSA/Ps, 80% (40/50), P < 0.001]; and with large amounts of mucin [HPs, 21.7% (5/23): TSAs, 17.9% (7/39): SSA/Ps, 72.0% (36/50), P < 0.001]. In magnified colonoscopic findings, 17 lesions showed either type II pit pattern alone or partial type II pit pattern as the basic architecture, with 14 HPs (14/17, 70.0%) and 3 SSA/Ps. Magnified colonoscopy showed the type II-O pit pattern as characteristic of SSA/Ps [sensitivity 83.7% (41/49), specificity 85.7% (54/63)]. Cancer was also present in three lesions, in all of which a type VI pit pattern was also present within the same lesion. There were four HPs and four TSAs each. The type IV-S pit pattern was characteristic of TSAs [sensitivity 96.7% (30/31), specificity 89.9% (72/81)]. Cancer was present in one lesion, in which a type VI pit pattern was also present within the same lesion. In our study, serrated lesions of the colorectum also possessed the features described in previous reports of conventional colonoscopic findings. The pit pattern diagnosis using magnifying colonoscopy, particularly magnified colonoscopic findings using subclassifications of surface architecture, reflected the pathological characteristics of SSA/Ps and TSAs, and will be useful for colonoscopic diagnosis. We suggest that this system could be a good diagnostic tool for SSA/Ps using magnifying colonoscopy.

Sea-Salt Aerosol Forecasts Compared with Wave and Sea-Salt Measurements in the Open Mediterranean Sea

NASA Astrophysics Data System (ADS)

Kishcha, P.; Starobinets, B.; Bozzano, R.; Pensieri, S.; Canepa, E.; Nickovie, S.; di Sarra, A.; Udisti, R.; Becagli, S.; Alpert, P.

2012-03-01

Sea-salt aerosol (SSA) could influence the Earth's climate acting as cloud condensation nuclei. However, there were no regular measurements of SSA in the open sea. At Tel-Aviv University, the DREAM-Salt prediction system has been producing daily forecasts of 3-D distribution of sea-salt aerosol concentrations over the Mediterranean Sea (http://wind.tau.ac.il/saltina/ salt.html). In order to evaluate the model performance in the open sea, daily modeled concentrations were compared directly with SSA measurements taken at the tiny island of Lampedusa, in the Central Mediterranean. In order to further test the robustness of the model, the model performance over the open sea was indirectly verified by comparing modeled SSA concentrations with wave height measurements collected by the ODAS Italia 1 buoy and the Llobregat buoy. Model-vs.-measurement comparisons show that the model is capable of producing realistic SSA concentrations and their day-today variations over the open sea, in accordance with observed wave height and wind speed.

Experiment Study on Determination of Surface Area of Finegrained Soils by Mercury Intrusion Porosimetry

NASA Astrophysics Data System (ADS)

Yan, X. Q.; Zhou, C. Y.; Fang, Y. G.; Lin, L. S.

2017-12-01

The specific surface area (SSA) has a great influence on the physical and chemical properties of fine-grained soils. Determination of specific surface area is an important content for fine-grained soils micro-meso analysis and characteristic research. In this paper, mercury intrusion porosimetry (MIP) was adopted to determine the SSA of fine-grained soils including quartz, kaolinite, bentonite and natural Shenzhen soft clay. The test results show that the average values of SSA obtained by MIP are 0.78m2/g, 11.31m2/g, 57.28m2/g and 27.15m2/g respectively for very fine-grained quartz, kaolin, bentonite and natural Shenzhen soft clay, and that it is feasible to apply MIP to obtain the SSA of fine-grained soils through statistical analysis of 97 samples. Through discussion, it is necessary to consider the state of fine-grained soils such as pore ratio when the SSA of fine-grained soils is determined by MIP.

Dual-reporter surrogate systems for efficient enrichment of genetically modified cells.

PubMed

Ren, Chonghua; Xu, Kun; Liu, Zhongtian; Shen, Juncen; Han, Furong; Chen, Zhilong; Zhang, Zhiying

2015-07-01

Isolation of genetically modified cells generated by designed nucleases are challenging, since they are often phenotypically indistinguishable from their parental cells. To efficiently enrich genetically modified cells, we developed two dual-reporter surrogate systems, namely NHEJ-RPG and SSA-RPG based on NHEJ and SSA repair mechanisms, respectively. Repair and enrichment efficiencies of these two systems were compared using different nucleases. In both CRISPR-Cas9- and ZFNs-induced DSB repair studies, we found that the efficiency and sensitivity of the SSA-RPG reporter with direct repeat length more than 200 bp were much higher than the NHEJ-RPG reporter. By utilizing the SSA-RPG reporter, we achieved the enrichment for indels in several endogenous loci with 6.3- to 34.8-fold of non-selected cells. Thus, the highly sensitive SSA-RPG reporter can be used for activity validation of designed nucleases and efficient enrichment of genetically modified cells. Besides, our systems offer alternative enrichment choices either by puromycin selection or FACS.

Blood donors' perceptions, motivators and deterrents in Sub-Saharan Africa - a scoping review of evidence.

PubMed

Asamoah-Akuoko, Lucy; Hassall, Oliver W; Bates, Imelda; Ullum, Henrik

2017-06-01

Achieving an adequate blood supply in Sub-Saharan Africa (SSA) through donor mobilization and retention is crucial. Factors that motivate or deter blood donors vary according to beliefs and social norms. Understanding the factors that influence blood donation behaviour in SSA is vital to developing effective strategies to address blood donor motivation and retention. This review of 35 studies from 16 SSA countries collates available evidence concerning the perceptions, motivators and deterrents that influence blood donors in SSA. The review revealed a common understanding that blood and blood donation save lives. The main deterrent to blood donation was fear due to lack of knowledge and discouraging spiritual, religious and cultural perceptions of blood donation. The main motivators for blood donation were altruism, donating blood for family and incentives. The findings support the need for targeted, culturally sensitive education, recruitment and retention strategies to improve the blood supply in SSA. © 2017 John Wiley & Sons Ltd.

Taxon-specific aerosolization of bacteria and viruses in an experimental ocean-atmosphere mesocosm.

PubMed

Michaud, Jennifer M; Thompson, Luke R; Kaul, Drishti; Espinoza, Josh L; Richter, R Alexander; Xu, Zhenjiang Zech; Lee, Christopher; Pham, Kevin M; Beall, Charlotte M; Malfatti, Francesca; Azam, Farooq; Knight, Rob; Burkart, Michael D; Dupont, Christopher L; Prather, Kimberly A

2018-05-22

Ocean-derived, airborne microbes play important roles in Earth's climate system and human health, yet little is known about factors controlling their transfer from the ocean to the atmosphere. Here, we study microbiomes of isolated sea spray aerosol (SSA) collected in a unique ocean-atmosphere facility and demonstrate taxon-specific aerosolization of bacteria and viruses. These trends are conserved within taxonomic orders and classes, and temporal variation in aerosolization is similarly shared by related taxa. We observe enhanced transfer into SSA of Actinobacteria, certain Gammaproteobacteria, and lipid-enveloped viruses; conversely, Flavobacteriia, some Alphaproteobacteria, and Caudovirales are generally under-represented in SSA. Viruses do not transfer to SSA as efficiently as bacteria. The enrichment of mycolic acid-coated Corynebacteriales and lipid-enveloped viruses (inferred from genomic comparisons) suggests that hydrophobic properties increase transport to the sea surface and SSA. Our results identify taxa relevant to atmospheric processes and a framework to further elucidate aerosolization mechanisms influencing microbial and viral transport pathways.

Same-sex attraction, social relationships, psychosocial functioning, and school performance in early adolescence.

PubMed

Bos, Henny M W; Sandfort, Theo G M; de Bruyn, Eddy H; Hakvoort, Esther M

2008-01-01

The authors examined whether 13- to 15-year-old adolescents who experience feelings of same-sex attraction (SSA) differ from those without such feelings in the quality of relationships with parents, peers, and class mentors and in psychosocial functioning (health status and school performance). The authors also assessed whether differences in psychosocial functioning resulted from differences in the quality of social relationships. Data were collected from 866 Dutch high school students (mean age 13.61 years) by means of a computer-based questionnaire. Of the participants, 74 (8.5%) reported having feelings of SSA. The participants with SSA rated the quality of their relationships with their fathers and their peers lower than did those without SSA. Participants with SSA also had poorer mental health (higher levels of depression and lower levels of self-esteem) and lower school performance. A mediation analysis revealed that differences in psychosocial functioning resulted from differences in the quality of the same-sex attracted youths' social relationships, especially with fathers and peers. Copyright (c) 2008 APA.

BOREAS RSS-18 Level-1B AVIRIS Imagery: At-Sensor Radiance in BIL Format

NASA Technical Reports Server (NTRS)

Newcomer, Jeffrey A.; Hall, Forrest G. (Editor); Nickerson, Jaime (Editor); Green, Robert O.; Smith, David E. (Technical Monitor)

2000-01-01

These data were collected and processed by the BOREAS RSS-18 team at NASA JPL. Data were acquired for BOREAS with NASA's AVIRIS. This optical sensor measures images that consist of spectra from 400 to 2500 nm at 10-nm sampling. These spectra are acquired as images with 20-meter spatial resolution, 11-km swath width and up to 800-km length. The measurements are spectrally, radiometrically, and geometrically calibrated. Spatially, the data are focused on the BOREAS NSA and SSA near Thompson, Manitoba, and Candle Lake, Saskatchewan, Canada, respectively. AVIRIS data were collected in 1994 during the Thaw campaign at the NSA and SSA, at the SSA in IFC-1, and at the NSA and SSA in both IFC-2 and IFC-3. In 1996, AVIRIS was deployed in the winter and summer campaigns in the SSA only. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Viral Space Situational Awareness

NASA Astrophysics Data System (ADS)

Gleckler, A.; Butterfield, M. C.

2012-09-01

Viral SSA takes advantage of the amateur astronomy community to provide an extremely low-cost and geographically-diverse network of optical SSA sites. In the spirit of programs such as DARPA's Grand Challenge and the National Weather Service's program of providing amateur meteorologists with weather stations linked to a central professional meteorological facility, we form a cooperative bond with a willing community of technically-minded individuals. We term this program "viral" because we will qualify an initial set of astronomers for SSA operation and then use word of mouth in the astronomy community, as well as an outreach program, to pull in new observers. The use of modern remote controlled telescopes allows the incorporation of certified amateur, university, and commercial telescope systems. The availability of the local Viral SSA member for troubleshooting eliminates most significant costs of operating a large network. In this talk, we discuss the key concepts of Viral SSA and the route to a network of 100+ sites in a three year or less timeframe.

An Improved Source-Scanning Algorithm for Locating Earthquake Clusters or Aftershock Sequences

NASA Astrophysics Data System (ADS)

Liao, Y.; Kao, H.; Hsu, S.

2010-12-01

The Source-scanning Algorithm (SSA) was originally introduced in 2004 to locate non-volcanic tremors. Its application was later expanded to the identification of earthquake rupture planes and the near-real-time detection and monitoring of landslides and mud/debris flows. In this study, we further improve SSA for the purpose of locating earthquake clusters or aftershock sequences when only a limited number of waveform observations are available. The main improvements include the application of a ground motion analyzer to separate P and S waves, the automatic determination of resolution based on the grid size and time step of the scanning process, and a modified brightness function to utilize constraints from multiple phases. Specifically, the improved SSA (named as ISSA) addresses two major issues related to locating earthquake clusters/aftershocks. The first one is the massive amount of both time and labour to locate a large number of seismic events manually. And the second one is to efficiently and correctly identify the same phase across the entire recording array when multiple events occur closely in time and space. To test the robustness of ISSA, we generate synthetic waveforms consisting of 3 separated events such that individual P and S phases arrive at different stations in different order, thus making correct phase picking nearly impossible. Using these very complicated waveforms as the input, the ISSA scans all model space for possible combination of time and location for the existence of seismic sources. The scanning results successfully associate various phases from each event at all stations, and correctly recover the input. To further demonstrate the advantage of ISSA, we apply it to the waveform data collected by a temporary OBS array for the aftershock sequence of an offshore earthquake southwest of Taiwan. The overall signal-to-noise ratio is inadequate for locating small events; and the precise arrival times of P and S phases are difficult to determine. We use one of the largest aftershocks that can be located by conventional methods as our reference event to calibrate the controlling parameters of ISSA. These parameters include the overall Vp/Vs ratio (because a precise S velocity model was unavailable), the length of scanning time window, and the weighting factor for each station. Our results show that ISSA is not only more efficient in locating earthquake clusters/aftershocks, but also capable of identifying many events missed by conventional phase-picking methods.

Newborn infant with maternal anti-SSA antibody-induced complete heart block accompanying cardiomyopathy.

PubMed

Iida, Midori; Inamura, Noboru; Takeuchi, Makoto

2006-01-01

Newborn case of maternal anti-SSA antibody-induced congenital complete heart block (CCHB) accompanying cardiomyopathy is presented. Unexpectedly, she died of ventricular tachycardia, not bradycardia, 6 days after birth. Autopsy revealed left ventricular cardiomyopathy with endocardial fibroelastosis. Thus, when evaluating fetal cardiac performance in cases of maternal anti-SSA antibody-induced CCHB, it is necessary to pay attention to myocardial attributes such as endocardial hyperplasia.

Comparison of BRDF-Predicted and Observed Light Curves of GEO Satellites

NASA Astrophysics Data System (ADS)

Ceniceros, A.; Dao, P.; Gaylor, D.; Rast, R.; Anderson, J.; Pinon, E., III

Although the amount of light received by sensors on the ground from Resident Space Objects (RSOs) in geostationary orbit (GEO) is small, information can still be extracted in the form of light curves (temporal brightness or apparent magnitude). Previous research has shown promising results in determining RSO characteristics such as shape, size, reflectivity, and attitude by processing simulated light curve data with various estimation algorithms. These simulated light curves have been produced using one of several existing analytic Bidirectional Reflectance Distribution Function (BRDF) models. These BRDF models have generally come from researchers in computer graphics and machine vision and have not been shown to be realistic for telescope observations of RSOs in GEO. While BRDFs have been used for SSA analysis and characterization, there is a lack of research on the validation of BRDFs with regards to real data. In this paper, we compared telescope data provided by the Air Force Research Laboratory (AFRL) with predicted light curves from the Ashikhmin-Premoze BRDF and two additional popular illumination models, Ashikhmin-Shirley and Cook-Torrance. We computed predicted light curves based on two line mean elements (TLEs), shape model, attitude profile, observing ground station location, observation time and BRDF. The predicted light curves were then compared with AFRL telescope data. The selected BRDFS provided accurate apparent magnitude trends and behavior, but uncertainties due to lack of attitude information and deficiencies in our satellite model prevented us from obtaining a better match to the real data. The current findings present a foundation for ample future research.

Effect of lime addition during sewage sludge treatment on characteristics of resulting SSA when it is used in cementitious materials.

PubMed

Vouk, D; Nakic, D; Štirmer, N; Baricevic, A

2017-02-01

Final disposal of sewage sludge is important not only in terms of satisfying the regulations, but the aspect of choosing the optimal wastewater treatment technology, including the sludge treatment. In most EU countries, significant amounts of stabilized and dewatered sludge are incinerated, and sewage sludge ash (SSA) is generated as a by product. At the same time, lime is one of the commonly used additives in the sewage sludge treatment primarily to stabilize the sludge. In doing so, the question arose how desirable is such addition of lime if the sludge is subsequently incinerated, and the generated ash is further used in the production of cementitious materials. A series of mortars were prepared where 10-20% of the cement fraction was replaced by SSA. Since all three types of analyzed SSA (without lime, with lime added during sludge stabilization and with extra lime added during sludge incineration) yielded nearly same results, it can be concluded that if sludge incineration is accepted solution, lime addition during sludge treatment is unnecessary even from the standpoint of preserving the pozzolanic properties of the resulting SSA. Results of the research carried out on cement mortars point to the great possibilities of using SSA in concrete industry.

Comparisons of spectral aerosol single scattering albedo in Seoul, South Korea

NASA Astrophysics Data System (ADS)

Mok, Jungbin; Krotkov, Nickolay A.; Torres, Omar; Jethva, Hiren; Li, Zhanqing; Kim, Jhoon; Koo, Ja-Ho; Go, Sujung; Irie, Hitoshi; Labow, Gordon; Eck, Thomas F.; Holben, Brent N.; Herman, Jay; Loughman, Robert P.; Spinei, Elena; Lee, Seoung Soo; Khatri, Pradeep; Campanelli, Monica

2018-04-01

Quantifying aerosol absorption at ultraviolet (UV) wavelengths is important for monitoring air pollution and aerosol amounts using current (e.g., Aura/OMI) and future (e.g., TROPOMI, TEMPO, GEMS, and Sentinel-4) satellite measurements. Measurements of column average atmospheric aerosol single scattering albedo (SSA) are performed on the ground by the NASA AERONET in the visible (VIS) and near-infrared (NIR) wavelengths and in the UV-VIS-NIR by the SKYNET networks. Previous comparison studies have focused on VIS and NIR wavelengths due to the lack of co-incident measurements of aerosol and gaseous absorption properties in the UV. This study compares the SKYNET-retrieved SSA in the UV with the SSA derived from a combination of AERONET, MFRSR, and Pandora (AMP) retrievals in Seoul, South Korea, in spring and summer 2016. The results show that the spectrally invariant surface albedo assumed in the SKYNET SSA retrievals leads to underestimated SSA compared to AMP values at near UV wavelengths. Re-processed SKYNET inversions using spectrally varying surface albedo, consistent with the AERONET retrieval improve agreement with AMP SSA. The combined AMP inversions allow for separating aerosol and gaseous (NO2 and O3) absorption and provide aerosol retrievals from the shortest UVB (305 nm) through VIS to NIR wavelengths (870 nm).

Isolating the effect of pore size distribution on electrochemical double-layer capacitance using activated fluid coke

NASA Astrophysics Data System (ADS)

Zuliani, Jocelyn E.; Tong, Shitang; Kirk, Donald W.; Jia, Charles Q.

2015-12-01

Electrochemical double-layer capacitors (EDLCs) use physical ion adsorption in the capacitive electrical double layer of high specific surface area (SSA) materials to store electrical energy. Previous work shows that the SSA-normalized capacitance increases when pore diameters are less than 1 nm. However, there still remains uncertainty about the charge storage mechanism since the enhanced SSA-normalized capacitance is not observed in all microporous materials. In previous studies, the total specific surface area and the chemical composition of the electrode materials were not controlled. The current work is the first reported study that systematically compares the performance of activated carbon prepared from the same raw material, with similar chemical composition and specific surface area, but different pore size distributions. Preparing samples with similar SSAs, but different pores sizes is not straightforward since increasing pore diameters results in decreasing the SSA. This study observes that the microporous activated carbon has a higher SSA-normalized capacitance, 14.1 μF cm-2, compared to the mesoporous material, 12.4 μF cm-2. However, this enhanced SSA-normalized capacitance is only observed above a threshold operating voltage. Therefore, it can be concluded that a minimum applied voltage is required to induce ion adsorption in these sub-nanometer micropores, which increases the capacitance.

HIV epidemic and human rights among men who have sex with men in sub-Saharan Africa: Implications for HIV prevention, care, and surveillance.

PubMed

Abara, Winston E; Garba, Ibrahim

2017-04-01

Recent research has presented evidence that men who have sex with men (MSM) bear a disproportionate burden of HIV and are at increased risk for HIV in sub-Saharan Africa (SSA). However, many countries in SSA have failed to address the needs of MSM in national HIV/AIDS programmes. Furthermore, many MSM face structural barriers to HIV prevention and care, the most significant of which include laws that criminalise male-to-male sexual contact and facilitate stigma and discrimination. This in turn increases the vulnerability of MSM to acquiring HIV and presents barriers to HIV prevention, care, and surveillance. This relationship illustrates the link between human rights, social justice, and health outcomes and presents considerable challenges to addressing the HIV epidemic among MSM in SSA. The response to the HIV epidemic in SSA requires a non-discriminatory human rights approach to all at-risk groups, including MSM. Existing international human rights treaties, to which many SSA countries are signatories, and a 'health in all policies' approach provides a strong basis to reduce structural barriers to HIV prevention, care, surveillance, and research, and to ensure that all populations in SSA, including MSM, have access to the full range of rights that help ensure equal opportunities for health and wellness.

Urban groundwater quality in sub-Saharan Africa: current status and implications for water security and public health

NASA Astrophysics Data System (ADS)

Lapworth, D. J.; Nkhuwa, D. C. W.; Okotto-Okotto, J.; Pedley, S.; Stuart, M. E.; Tijani, M. N.; Wright, J.

2017-06-01

Groundwater resources are important sources of drinking water in Africa, and they are hugely important in sustaining urban livelihoods and supporting a diverse range of commercial and agricultural activities. Groundwater has an important role in improving health in sub-Saharan Africa (SSA). An estimated 250 million people (40% of the total) live in urban centres across SSA. SSA has experienced a rapid expansion in urban populations since the 1950s, with increased population densities as well as expanding geographical coverage. Estimates suggest that the urban population in SSA will double between 2000 and 2030. The quality status of shallow urban groundwater resources is often very poor due to inadequate waste management and source protection, and poses a significant health risk to users, while deeper borehole sources often provide an important source of good quality drinking water. Given the growth in future demand from this finite resource, as well as potential changes in future climate in this region, a detailed understanding of both water quantity and quality is required to use this resource sustainably. This paper provides a comprehensive assessment of the water quality status, both microbial and chemical, of urban groundwater in SSA across a range of hydrogeological terrains and different groundwater point types. Lower storage basement terrains, which underlie a significant proportion of urban centres in SSA, are particularly vulnerable to contamination. The relationship between mean nitrate concentration and intrinsic aquifer pollution risk is assessed for urban centres across SSA. Current knowledge gaps are identified and future research needs highlighted.

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

PubMed Central

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-01-01

The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer. In contrast, jet drops formed from the base of bursting bubbles are postulated to mainly produce larger supermicrometer particles from bulk seawater, which comprises largely salts and water-soluble organic species. However, here we demonstrate that jet drops produce up to 43% of total submicrometer SSA number concentrations, and that the fraction of SSA produced by jet drops can be modulated by marine biological activity. We show that the chemical composition, organic volume fraction, and ice nucleating ability of submicrometer particles from jet drops differ from those formed from film drops. Thus, the chemical composition of a substantial fraction of submicrometer particles will not be controlled by the composition of the sea surface microlayer, a major assumption in previous studies. This finding has significant ramifications for understanding the factors controlling the mixing state of submicrometer SSA particles and must be taken into consideration when predicting SSA impacts on clouds and climate. PMID:28630346

Sagittal Vertical Axias, Spinosacral Angle, Spinopelvic Angle, and T1 Pelvic Angle: Which Parameters May Effectively Predict the Quality of Life in Ankylosing Spondylitis Patients With Thoracolumbar Kyphosis?

PubMed

Zhang, Yun-Peng; Qian, Bang-Ping; Qiu, Yong; Qu, Zhe; Mao, Sai-Hu; Jiang, Jun; Zhu, Ze-Zhang

2017-08-01

This is a retrospective study. To identify the relationship between global sagittal alignment and health-related quality of life (HRQoL) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. Little data are available on correlation between global sagittal alignment and HRQoL in AS. A total of 107 AS patients were included in this study. The radiographic parameters were measured on lateral radiographs of the whole spine, including sagittal vertical axias (SVA), spinosacral angle (SSA), spinopelvic angle (SPA), and T1 pelvic angle (TPA). HRQoL was assessed using the oswestry disability index questionnaire, the bath ankylosing spondylitis disease activity index, the bath ankylosing spondylitis functional index, and short form-36 questionnaire. The patients were divided into 2 groups: group A (n=76, global kyphosis≤70 degrees), group B (n=31, global kyphosis>70 degrees). Statistical analysis was performed to identify significant differences between these 2 groups. In addition, correlation analysis and multiple regression analysis between radiologic parameters and clinical questionnaires were conducted. With respect to SVA, SSA, SPA, TPA, and HRQoL scores, significant differences were observed between 2 groups (P<0.05). Also, SVA, SSA, SPA, and TPA were significantly related to HRQoL. Multiple regression analysis revealed that SVA, SSA, SPA, and TPA were significant parameters in the prediction of HRQoL in AS patients with thoracolumbar kyphosis. Of note, HRQoL related much more to SSA and SPA than SVA and TPA. AS patients with moderate and severe deformity were demonstrated to be significantly different in terms of SVA, SSA, SPA, TPA, and HRQoL. Moreover, SVA, SSA, SPA, and TPA correlated with HRQoL significantly. In particular, SSA and SPA could better predict HRQoL than SVA and TPA in AS patients with thoracolumbar kyphosis.

ESA SSA Space Weather Services Supporting Space Surveillance and Tracking

NASA Astrophysics Data System (ADS)

Luntama, Juha-Pekka; Glover, Alexi; Hilgers, Alain; Fletcher, Emmet

2012-07-01

ESA Space Situational Awareness (SSA) Preparatory Programme was started in 2009. The objective of the programme is to support the European independent utilisation of and access to space research or services. This will be performed through providing timely and quality data, information, services and knowledge regarding the environment, the threats and the sustainable exploitation of the outer space surrounding the planet Earth. SSA serves the implementation of the strategic missions of the European Space Policy based on the peaceful uses of the outer space by all states, by supporting the autonomous capacity to securely and safely operate the critical European space infrastructures. The Space Weather (SWE) Segment of the SSA will provide user services related to the monitoring of the Sun, the solar wind, the radiation belts, the magnetosphere and the ionosphere. These services will include near real time information and forecasts about the characteristics of the space environment and predictions of space weather impacts on sensitive spaceborne and ground based infrastructure. The SSA SWE system will also include establishment of a permanent database for analysis, model development and scientific research. These services are will support a wide variety of user domains including spacecraft designers, spacecraft operators, human space flights, users and operators of transionospheric radio links, and space weather research community. The precursor SWE services to be established starting in 2010. This presentation provides an overview of the ESA SSA SWE services focused on supporting the Space Surveillance and Tracking users. This services include estimates of the atmospheric drag and archive and forecasts of the geomagnetic and solar indices. In addition, the SSA SWE system will provide nowcasts of the ionospheric group delay to support mitigation of the ionospheric impact on radar signals. The paper will discuss the user requirements for the services, the data requirements and the foreseen development needs for the ESA SSA SWE system before the full service capability is available.

A data-driven prediction method for fast-slow systems

NASA Astrophysics Data System (ADS)

Groth, Andreas; Chekroun, Mickael; Kondrashov, Dmitri; Ghil, Michael

2016-04-01

In this work, we present a prediction method for processes that exhibit a mixture of variability on low and fast scales. The method relies on combining empirical model reduction (EMR) with singular spectrum analysis (SSA). EMR is a data-driven methodology for constructing stochastic low-dimensional models that account for nonlinearity and serial correlation in the estimated noise, while SSA provides a decomposition of the complex dynamics into low-order components that capture spatio-temporal behavior on different time scales. Our study focuses on the data-driven modeling of partial observations from dynamical systems that exhibit power spectra with broad peaks. The main result in this talk is that the combination of SSA pre-filtering with EMR modeling improves, under certain circumstances, the modeling and prediction skill of such a system, as compared to a standard EMR prediction based on raw data. Specifically, it is the separation into "fast" and "slow" temporal scales by the SSA pre-filtering that achieves the improvement. We show, in particular that the resulting EMR-SSA emulators help predict intermittent behavior such as rapid transitions between specific regions of the system's phase space. This capability of the EMR-SSA prediction will be demonstrated on two low-dimensional models: the Rössler system and a Lotka-Volterra model for interspecies competition. In either case, the chaotic dynamics is produced through a Shilnikov-type mechanism and we argue that the latter seems to be an important ingredient for the good prediction skills of EMR-SSA emulators. Shilnikov-type behavior has been shown to arise in various complex geophysical fluid models, such as baroclinic quasi-geostrophic flows in the mid-latitude atmosphere and wind-driven double-gyre ocean circulation models. This pervasiveness of the Shilnikow mechanism of fast-slow transition opens interesting perspectives for the extension of the proposed EMR-SSA approach to more realistic situations.

A novel embeddable spherical smart aggregate for structural health monitoring: part I. Fabrication and electrical characterization

NASA Astrophysics Data System (ADS)

Kong, Qingzhao; Fan, Shuli; Bai, Xiaolong; Mo, Y. L.; Song, Gangbing

2017-09-01

Recently developed piezoceramic-based transducers, known as smart aggregates (SAs), have shown their applicability and versatility in various applications of structural health monitoring (SHM). The lead zirconate titanate (PZT) patches embedded inside SAs have different modes that are more suitable for generating or receiving different types of stress waves (e.g. P and S waves, each of which has a unique role in SHM). However, due to the geometry of the 2D PZT patch, the embedded SA can only generate or receive the stress wave in a single direction and thus greatly limits its applications. This paper is the first of a series of two companion papers that introduces the authors’ latest work in developing a novel, embeddable spherical smart aggregate (SSA) for the health monitoring of concrete structures. In addition to the 1D guided wave produced by SA, the SSA embedded in concrete structures can generate or receive omni-directional stress waves that can significantly improve the detection aperture and provide additional functionalities in SHM. In the first paper (Part I), the detailed fabrication procedures with the help of 3D printing technology and electrical characterization of the proposed SSA is presented. The natural frequencies of the SSA were experimentally obtained and further compared with the numerical results. In addition, the influence of the components’ thickness (spherical piezoceramic shell and epoxy) and outer radius (spherical piezoceramic shell and protection concrete) on the natural frequencies of the SSA were analytically studied. The results will help elucidate the key parameters that determine the natural frequencies of the SSA. The natural frequencies of the SSA can thus be designed for suitability in the damage detection of concrete structures. In the second paper (Part II), further numerical and experimental verifications on the performance of the proposed SSA in concrete structures will be discussed.

Smoke aerosol properties and ageing effects for Northern temperate and boreal regions derived from AERONET source and age attribution

NASA Astrophysics Data System (ADS)

Nikonovas, Tadas; North, Peter; Doerr, Stefan H.

2015-04-01

Particulate emissions from wildfires impact human health and have a large but uncertain effect on climate. Modelling schemes depend on information about emission factors, emitted particle microphysical and optical properties and ageing effects, while satellite retrieval algorithms make use of characteristic aerosol models to improve retrieval. Ground based remote sensing provides detailed aerosol characterisation, but does not contain information on source. A new method is presented to estimate plume origin land cover type and age for AERONET aerosol observations, employing trajectory modelling using the HYSPLIT model, and satellite active fire and aerosol optical thickness (AOT) observations from MODIS and AATSR. It is applied to AERONET stations located in or near Northern temperate and boreal forests, for the period 2002-2013. The results from 629 fire attributions indicate significant differences insize distributions and particle optical properties between different land cover types. Smallest fine mode median radius are attributed to plumes from cropland/natural vegetation mosaic (0.143 μm) and grasslands (0.147 μm) fires. Evergreen needleleaf forest emissions show a significantly smaller fine mode median radius (0.164 μm) than plumes from woody savannas (0.184 μm) and mixed forest (0.193 μm) fires. Smoke plumes are predominantly scattering for all of the classes with median single scattering albedo at 440 nm (SSA(440)) values close to 0.95 except the cropland emissions which have SSA(440) value of 0.9. Overall fine mode volume median radius increase rate is 0.0095μm per day for the first 4 days of ageing and 0.0084 μm per day for seven days of ageing. Changes in size were consistent with a decrease in Angstrom Exponent and increase in Asymmetry parameter. No significant changes in SSA(λ) with ageing were found. The implications of this work for improved modeling of aerosol radiative effects, which are relevant to both climate modelling and satellite aerosol retrieval schemes, are also discussed.

Utilizing Novel Non-traditional Sensor Tasking Approaches to Enhance the Space Situational Awareness Picture Maintained by the Space Surveillance Network

NASA Astrophysics Data System (ADS)

Herz, A.; Herz, E.; Center, K.; George, P.; Axelrad, P.; Mutschler, S.; Jones, B.

2016-09-01

The Space Surveillance Network (SSN) is tasked with the increasingly difficult mission of detecting, tracking, cataloging and identifying artificial objects orbiting the Earth, including active and inactive satellites, spent rocket bodies, and fragmented debris. Much of the architecture and operations of the SSN are limited and outdated. Efforts are underway to modernize some elements of the systems. Even so, the ability to maintain the best current Space Situational Awareness (SSA) picture and identify emerging events in a timely fashion could be significantly improved by leveraging non-traditional sensor sites. Orbit Logic, the University of Colorado and the University of Texas at Austin are developing an innovative architecture and operations concept to coordinate the tasking and observation information processing of non - traditional assets based on information-theoretic approaches. These confirmed tasking schedules and the resulting data can then be used to "inform" the SSN tasking process. The 'Heimdall Web' system is comprised of core tasking optimization components and accompanying Web interfaces within a secure, split architecture that will for the first time allow non-traditional sensors to support SSA and improve SSN tasking. Heimdall Web application components appropriately score/prioritize space catalog objects based on covariance, priority, observability, expected information gain, and probability of detect - then coordinate an efficient sensor observation schedule for non-SSN sensors contributing to the overall SSA picture maintained by the Joint Space Operations Center (JSpOC). The Heimdall Web Ops concept supports sensor participation levels of "Scheduled", "Tasked" and "Contributing". Scheduled and Tasked sensors are provided optimized observation schedules or object tracking lists from central algorithms, while Contributing sensors review and select from a list of "desired track objects". All sensors are "Web Enabled" for tasking and feedback, supplying observation schedules, confirmed observations and related data back to Heimdall Web to complete the feedback loop for the next scheduling iteration.

A Pharmacovigilance Approach for Post-Marketing in Japan Using the Japanese Adverse Drug Event Report (JADER) Database and Association Analysis.

PubMed

Fujiwara, Masakazu; Kawasaki, Yohei; Yamada, Hiroshi

2016-01-01

Rapid dissemination of information regarding adverse drug reactions is a key aspect for improving pharmacovigilance. There is a possibility that unknown adverse drug reactions will become apparent through post-marketing administration. Currently, although there have been studies evaluating the relationships between a drug and adverse drug reactions using the JADER database which collects reported spontaneous adverse drug reactions, an efficient approach to assess the association between adverse drug reactions of drugs with the same indications as well as the influence of demographics (e.g. gender) has not been proposed. We utilized the REAC and DEMO tables from the May 2015 version of JADER for patients taking antidepressant drugs (SSRI, SNRI, and NaSSA). We evaluated the associations using association analyses with an apriori algorithm. Support, confidence, lift, and conviction were used as indicators for associations. The highest score in adverse drug reactions for SSRI was obtained for "aspartate aminotransferase increased", "alanine aminotransferase increased", with values of 0.0059, 0.93, 135.5, and 13.9 for support, confidence, lift and conviction, respectively. For SNRI, "international normalized ratio increased", "drug interaction" were observed with 0.0064, 1.00, 71.9, and NA. For NaSSA, "anxiety", "irritability" were observed with 0.0058, 0.80, 49.9, and 4.9. For female taking SSRI, the highest support scores were observed in "twenties", "suicide attempt", whereas "thirties", "neuroleptic malignant syndrome" were observed for male. Second, for SNRI, "eighties", "inappropriate antidiuretic hormone secretion" were observed for female, whereas "interstitial lung disease" and "hepatitis fulminant" were for male. Finally, for NaSSA, "suicidal ideation" was for female, and "rhabdomyolysis" was for male. Different combinations of adverse drug reactions were noted between the antidepressants. In addition, the reported adverse drug reactions differed by gender. This approach using a large database for examining the associations can improve safety monitoring during the post-marketing phase.

A Pharmacovigilance Approach for Post-Marketing in Japan Using the Japanese Adverse Drug Event Report (JADER) Database and Association Analysis

PubMed Central

Fujiwara, Masakazu; Kawasaki, Yohei; Yamada, Hiroshi

2016-01-01

Background Rapid dissemination of information regarding adverse drug reactions is a key aspect for improving pharmacovigilance. There is a possibility that unknown adverse drug reactions will become apparent through post-marketing administration. Currently, although there have been studies evaluating the relationships between a drug and adverse drug reactions using the JADER database which collects reported spontaneous adverse drug reactions, an efficient approach to assess the association between adverse drug reactions of drugs with the same indications as well as the influence of demographics (e.g. gender) has not been proposed. Methods and Findings We utilized the REAC and DEMO tables from the May 2015 version of JADER for patients taking antidepressant drugs (SSRI, SNRI, and NaSSA). We evaluated the associations using association analyses with an apriori algorithm. Support, confidence, lift, and conviction were used as indicators for associations. The highest score in adverse drug reactions for SSRI was obtained for "aspartate aminotransferase increased", "alanine aminotransferase increased", with values of 0.0059, 0.93, 135.5, and 13.9 for support, confidence, lift and conviction, respectively. For SNRI, "international normalized ratio increased", "drug interaction" were observed with 0.0064, 1.00, 71.9, and NA. For NaSSA, "anxiety", "irritability" were observed with 0.0058, 0.80, 49.9, and 4.9. For female taking SSRI, the highest support scores were observed in "twenties", "suicide attempt", whereas "thirties", "neuroleptic malignant syndrome" were observed for male. Second, for SNRI, "eighties", "inappropriate antidiuretic hormone secretion" were observed for female, whereas "interstitial lung disease" and "hepatitis fulminant" were for male. Finally, for NaSSA, "suicidal ideation" was for female, and "rhabdomyolysis" was for male. Conclusions Different combinations of adverse drug reactions were noted between the antidepressants. In addition, the reported adverse drug reactions differed by gender. This approach using a large database for examining the associations can improve safety monitoring during the post-marketing phase. PMID:27119382

Methods of Single Station and Limited Data Analysis and Forecasting

DTIC Science & Technology

1985-08-15

example using real data. Discusses modifications of SSA technique in certain climatological regimes and describes some statistical tech- niques for SSA of... caster has access to radar or satellite observations, or any computer products during the period of his isolation. Where calculations are involved, it is...chapters of the text will deal with special topics such as modifications of the SSA technique that must be considered for certain clima- tological regimes

Protective Performance of Polyaniline-Sulfosalicylic Acid/Epoxy Coating for 5083 Aluminum

PubMed Central

Liu, Suyun; Liu, Li; Meng, Fandi; Li, Ying; Wang, Fuhui

2018-01-01

Epoxy coatings incorporating different content of sulfosalicylic acid doped polyaniline (PANI-SSA) have been investigated for corrosion protection of 5083 aluminum alloy in 3.5% NaCl solution. The performance of the coatings is studied using a combination of electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), gravimetric tests, adhesion tests, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the content of PANI-SSA not only affects the coating compactness and the transportation of aggressive medium, but also has a significant influence on the-based aluminum. The coating with 2 wt. % PANI-SSA exhibits the best corrosion inhibition due to its good protective properties and the formation of a complete PANI-SSA induced oxide layer. PMID:29438304

BOREAS TE-5 Leaf Carbon Isotope Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

2000-01-01

The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. This documentation describes leaf carbon isotope data that were collected in 1993 and 1994 at the NSA and SSA OJP sites, the SSA OBS site, and the NSA UBS site. In addition, leaf carbon isotope data were collected in 1994 only at the NSA and SSA OA sites. These data was collected to provide seasonal integrated physiological information for 10 to 15 common species at these 6 BOREAS sites. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Geochemical investigation of potentially harmful elements in household dust from a mercury-contaminated site, the town of Idrija (Slovenia).

PubMed

Bavec, Špela; Gosar, Mateja; Miler, Miloš; Biester, Harald

2017-06-01

A comprehensive geochemical investigation of potentially harmful elements (PHEs) in household dust from the town of Idrija (Slovenia), once a world-famous Hg mining town that is now seriously polluted, was performed for the first time. After aqua regia digestion, the content of mercury (Hg), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn) was measured. PHE-bearing particles were recognised and observed by scanning electron microscopy and energy-dispersive spectrometry before and after exposure to simulated stomach acid (SSA). Mercury binding forms were identified by Hg thermal desorption technique and gastric bioaccessible Hg was estimated after SSA extraction by ICP-MS. With regard to rural and urban background values for Slovenia, high Hg content (6-120 mg/kg) and slightly elevated As content (1-13 mg/kg) were found. Mercury pollution is a result of past mining and ore processing activities. Arsenic content is potentially associated with As enrichment in local soils. Four Hg binding forms were identified: all samples contained Hg bound to the dust matrix, 14 samples contained cinnabar, two samples contained metallic Hg (Hg 0 ), and one sample assumingly contained mercury oxide. After exposure to SSA, Hg-bearing phases showed no signs of dissolution, while other PHE-bearing phases were significantly morphologically and/or chemically altered. Estimated gastric Hg bioaccessibility was low (<0.006-0.09 %), which is in accordance with identified Hg binding forms and high organic carbon content (15.9-31.5 %) in the dust samples.

BOREAS TE-6 Multiband Vegetation Imager Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Kucharik, Christopher J.

2000-01-01

The BOREAS TE-6 team collected data in support of its efforts to examine the influence of vegetation and climate on the major carbon fluxes in boreal tree species. A newly developed ground-based canopy imaging system called an MVI was tested and used by the BOREAS TE-06 team to collect measurements of the canopy crap fraction (sky fraction), canopy gap-size distribution (size and frequency of gaps between foliage in canopy), branch architecture, and leaf angle distribution (fraction of leaf area in specific leaf inclination classes assuming azimuthal symmetry). Measurements of the canopy gap-size distribution are used to derive canopy clumping indices that can be used to adjust indirect LAI measurements made in nonrandom forests. These clumping factors will also help to describe the radiation penetration in clumped canopies more accurately by allowing for simple adjustments to Beer's law. Measurements of the above quantities were obtained at BOREAS NSA-OJP site in IFC-2 in 1994, at the SSA-OA in July 1995, and at the SSA-OBS and SSA-OA sites in IFC-2 in 1996. Modeling studies were also performed to further validate MVI measurements and to gain a more complete understanding of boreal forest canopy architecture. By using MVI measurements and Monte Carlo simulations, clumping indices as a function of zenith angle were derived for the three main boreal species studied during BOREAS. The analyzed data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

BOREAS RSS-7 LAI, Gap Fraction, and FPAR Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing

2000-01-01

The BOREAS RSS-7 team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of Leaf Area Index (LAI) from remotely sensed images. Ground measurements of LAI and Fraction of Photosynthetically Active Radiation (FPAR) absorbed by the plant canopy were made using the LAI-2000 and TRAC optical instruments during focused periods from 09-Aug-1993 to 19-Sep-1994. The measurements were intensive at the NSA and SSA tower sites, but were made just once or twice at auxiliary sites. The final processed LAI and FPAR data set is contained in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884).

Extending the Deep Blue aerosol record from SeaWiFS and MODIS to NPP-VIIRS

NASA Technical Reports Server (NTRS)

Sayer, Andrew M.; Hsu, Nai-Yung Christina; Bettenhausen, Corey; Lee, Jaehwa

2015-01-01

Deep Blue expands AOD coverage to deserts and other bright surfaces. Using multiple similar satellite sensors enables us to obtain a long data record. The Deep Blue family consists of three separate aerosol optical depth (AOD) retrieval algorithms: 1. Bright Land: Surface reflectance database, BRDF correction. AOD retrieved separately at each of 412, 470/490, (650) nm. SSA retrieved for heavy dust events. 2. Dark Land: Spectral/directional surface reflectance relationship. AOD retrieved separately at 470/490 and 650 nm. 3. Water: Surface BRDF including glint, foam, underlight. Multispectral inversion (Not present in MODISdataset) All report the AOD at 550 nm, and Ångström exponent (AE).

Molecular features of colorectal hyperplastic polyps and sessile serrated adenoma/polyps from Korea.

PubMed

Kim, Kyoung-Mee; Lee, Eui Jin; Ha, Sangyun; Kang, So Young; Jang, Kee-Taek; Park, Cheol Keun; Kim, Jin Yong; Kim, Young Ho; Chang, Dong Kyung; Odze, Robert Daniel

2011-09-01

Abundant recent data suggest that sessile serrated adenoma/polyp (SSA/P) is an early precursor lesion in the serrated pathway of carcinogenesis. It is believed that SSA/Ps develop cancer by an SSA/P-dysplasia-carcinoma sequence. Hyperplastic polyps (HPs) share some histologic and molecular characteristics with SSA/P, but it is unclear whether SSA/Ps are derived from HPs or whether they develop by a different pathogenetic pathway. Previous studies have shown that serrated polyps from Korean patients show different prevalence rates of certain molecular abnormalities compared with similar lesions from American patients, and this suggests that lifestyle and dietary factors may influence the serrated neoplasia pathway. The purpose of this study was to evaluate the molecular features of HPs and SSA/Ps, the latter both with and without dysplasia, from Korean patients and to compare the findings with similar lesions from American patients. One hundred and eleven serrated polyps, consisting of 45 HPs (30 microvesicular, 11 goblet cell, 4 mucin depleted) and 56 SSA/Ps (36 with dysplasia, 20 without dysplasia), were retrieved from the pathology files of a large medical center in Korea and 38 SSA/P from American patients were evaluated for BRAF and KRAS mutations, microsatellite instability, and hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT), hMLH1, adenomatous polyposis coli (APC), p16, methylated in tumor-1 (MINT-1), MINT2, and MINT31. Methylation of hMLH1 was performed using 2 different sets of primers. Twenty-three conventional adenomas from Korean patients were included as controls. The data were compared between polyp subtypes and between polyps in the right versus the left colon. With regard to HP, KRAS mutations were present in 31.1% of polyps and BRAF mutations in 46.7% of polyps. KRAS mutations were significantly more common in goblet cell HP and BRAF in microvesicular HP (MVHP). Methylation of MGMT, hMLH1, APC, p16, MINT1, MINT2, and MINT31 were present in 42.2%, 64.4% (and 24.4%), 37.8%, 60%, 68.9%, 51.1%, and 60% of HPs. CpG island methylator phenotype high was noted in 60% of HPs. Methylation of hMLH1, p16, MINT2, and MINT31 were more frequent in MVHPs compared with other types of HPs. In contrast, SSA/Ps showed KRAS and BRAF mutations in 12.5% and 60.7% of cases, respectively. Methylation of all tumor-related genes, except hMLH1 (23.2% using 1 type of primers) and APC (37.5%), occurred in >50% of lesions, and CpG island methylator phenotype (CIMP) high was noted in 76.8% of cases. None of the molecular findings were significantly more common in SSA/P with, versus those without, dysplasia, but only 2 of the 36 polyps with dysplasia were of the conventional adenomatous type; the remainder (34 of 36) was of the serrated type. Nevertheless, both SSA/P with conventional adenomatous dysplasia showed methylation of MGMT, APC, MINT1, and MINT31 and were CIMP high. BRAF mutations, methylation of most tumor related genes, and CIMP high occurred more frequently in HPs and SSA/Ps in the right colon, compared with the left colon. In fact, no significant differences were observed between HPs and SSPs of the right colon and HPs and SSA/Ps from the left colon. Furthermore, compared with American patients, Korean male individuals were affected more frequently than female individuals, and both BRAF mutations and hMLH1 methylation were less frequent in the latter compared with the former. We conclude that HPs and SSA/Ps in Korean patients share some, but not all, clinical and molecular characteristics to those that occur in Americans. The data support the theory that the right and left colon are biologically different with regard to susceptibility to serrated cancer, and that anatomic location (right vs. left) may be a more significant risk factor of progression than the histologic type of polyp. Our data also support the theory that right-sided MVHPs may be a precursor to SSA/P.

Rooting for food security in Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Guilpart, Nicolas; Grassini, Patricio; van Wart, Justin; Yang, Haishun; van Ittersum, Martin K.; van Bussel, Lenny G. J.; Wolf, Joost; Claessens, Lieven; Leenaars, Johan G. B.; Cassman, Kenneth G.

2017-11-01

There is a persistent narrative about the potential of Sub-Saharan Africa (SSA) to be a ‘grain breadbasket’ because of large gaps between current low yields and yield potential with good management, and vast land resources with adequate rainfall. However, rigorous evaluation of the extent to which soils can support high, stable yields has been limited by lack of data on rootable soil depth of sufficient quality and spatial resolution. Here we use location-specific climate data, a robust spatial upscaling approach, and crop simulation to assess sensitivity of rainfed maize yields to root-zone water holding capacity. We find that SSA could produce a modest maize surplus but only if rootable soil depths are comparable to that of other major breadbaskets, such as the US Corn Belt and South American Pampas, which is unlikely based on currently available information. Otherwise, producing surplus grain for export will depend on expansion of crop area with the challenge of directing this expansion to regions where soil depth and rainfall are supportive of high and consistent yields, and where negative impacts on biodiversity are minimal.

An Event-Based Verification Scheme for the Real-Time Flare Detection System at Kanzelhöhe Observatory

NASA Astrophysics Data System (ADS)

Pötzi, W.; Veronig, A. M.; Temmer, M.

2018-06-01

In the framework of the Space Situational Awareness program of the European Space Agency (ESA/SSA), an automatic flare detection system was developed at Kanzelhöhe Observatory (KSO). The system has been in operation since mid-2013. The event detection algorithm was upgraded in September 2017. All data back to 2014 was reprocessed using the new algorithm. In order to evaluate both algorithms, we apply verification measures that are commonly used for forecast validation. In order to overcome the problem of rare events, which biases the verification measures, we introduce a new event-based method. We divide the timeline of the Hα observations into positive events (flaring period) and negative events (quiet period), independent of the length of each event. In total, 329 positive and negative events were detected between 2014 and 2016. The hit rate for the new algorithm reached 96% (just five events were missed) and a false-alarm ratio of 17%. This is a significant improvement of the algorithm, as the original system had a hit rate of 85% and a false-alarm ratio of 33%. The true skill score and the Heidke skill score both reach values of 0.8 for the new algorithm; originally, they were at 0.5. The mean flare positions are accurate within {±} 1 heliographic degree for both algorithms, and the peak times improve from a mean difference of 1.7± 2.9 minutes to 1.3± 2.3 minutes. The flare start times that had been systematically late by about 3 minutes as determined by the original algorithm, now match the visual inspection within -0.47± 4.10 minutes.

Validation of the Social Security Administration Life Tables (2004-2014) in Localized Prostate Cancer Patients within the Surveillance, Epidemiology, and End Results database.

PubMed

Preisser, Felix; Bandini, Marco; Mazzone, Elio; Nazzani, Sebastiano; Marchioni, Michele; Tian, Zhe; Saad, Fred; Pompe, Raisa S; Shariat, Shahrokh F; Heinzer, Hans; Montorsi, Francesco; Huland, Hartwig; Graefen, Markus; Tilki, Derya; Karakiewicz, Pierre I

2018-05-22

Accurate life expectancy estimation is crucial in clinical decision-making including management and treatment of clinically localized prostate cancer (PCa). We hypothesized that Social Security Administration (SSA) life tables' derived survival estimates closely follow observed survival of PCa patients. To test this relationship, we examined 10-yr overall survival rates in patients with clinically localized PCa and compared it with survival estimates derived from the SSA life tables. Within the Surveillance, Epidemiology, and End Results database (2004), we identified patients aged >50-<90yr. Follow-up was at least 10 yr for patients who did not die of disease or other causes. Monte Carlo method was used to define individual survival in years, according to the SSA life tables (2004-2014). Subsequently, SSA life tables' predicted survival was compared with observed survival rates in Kaplan-Meier analyses. Subgroup analyses were stratified according to treatment type and D'Amico risk classification. Overall, 39191 patients with localized PCa were identified. At 10-yr follow-up, the SSA life tables' predicted survival was 69.5% versus 73.1% according to the observed rate (p<0.0001). The largest differences between estimated versus observed survival rates were recorded for D'Amico low-risk PCa (8.0%), brachytherapy (9.1%), and radical prostatectomy (8.6%) patients. Conversely, the smallest differences were recorded for external beam radiotherapy (1.7%) and unknown treatment type (1.6%) patients. Overall, SSA life tables' predicted life expectancy closely approximate observed overall survival rates. However, SSA life tables' predicted rates underestimate by as much as 9.1% the survival in brachytherapy patients, as well as in D'Amico low-risk and radical prostatectomy patients. In these patient categories, an adjustment for the degree of underestimation might be required when counseling is provided in clinical practice. Social Security Administration (SSA) life tables' predicted life expectancy closely approximate observed overall survival rates. However, SSA life tables' predicted rates underestimate by as much as 9.1% the survival in brachytherapy patients, as well as in D'Amico low-risk and radical prostatectomy patients. Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Preliminary approach of the MELiSSA loop energy balance

NASA Astrophysics Data System (ADS)

Poulet, Lucie; Lamaze, Brigitte; Lebrun, Jean

Long duration missions, such as the establishment of permanent bases on the lunar surface or the travel to Mars, require a huge amount of life support consumables (e.g. food, water and oxygen). Current rockets are at the moment unable to launch such a mass from Earth. Consequently Regenerative Life Support Systems are necessary to sustain long-term manned space mission to increase recycling rates and so reduce the launched mass. Thus the European and Canadian research has been concentrating on the MELiSSA (Micro-Ecological Life Support System Alternative) project over the last 20 years. MELiSSA is an Environmental Controlled Life Support System (ECLSS), i.e. a closed regenerative loop inspired of a lake ecosystem. Using light as a source of energy, MELiSSA's goal is the recovery of food, water and oxygen from CO2 and organic wastes, using microorganisms and higher plants. The architecture of a ECLSS depends widely on the mission scenario. To compare several ECLSS architectures and in order to be able to evaluate them, ESA is developing a multi criteria evaluation tool: ALISSE (Advanced LIfe Support System Evaluator). One of these criteria is the energy needed to operate the ECLSS. Unlike other criteria like the physical mass, the energy criterion has not been investigated yet and needs hence a detailed analysis. It will consequently be the focus of this study. The main objective of the work presented here is to develop a dynamic tool able to estimate the energy balance for several configurations of the MELiSSA loop. The first step consists in establishing the energy balance using concrete figures from the MELiSSA Pilot Plant (MPP). This facility located at the Universitat Autonoma de Barcelona (UAB) is aimed at the ground demonstration of the MELiSSA loop. The MELiSSA loop is structured on several subsystems; each of them is characterized by supplies, exhausts and process reactions. For the purpose of this study (i.e. a generic tool) the solver EES (Engineering Equation Solver) is used. As a result, several configurations of the MELiSSA loop are studied. The main issues in terms of energy costs are identified and in the meantime improvement opportunities, i.e. reduction of energy consumption, are diagnosed.

Community analysis of biofilms on flame-oxidized stainless steel anodes in microbial fuel cells fed with different substrates.

PubMed

Eyiuche, Nweze Julius; Asakawa, Shiho; Yamashita, Takahiro; Ikeguchi, Atsuo; Kitamura, Yutaka; Yokoyama, Hiroshi

2017-06-29

The flame-oxidized stainless steel anode (FO-SSA) is a newly developed electrode that enhances microbial fuel cell (MFC) power generation; however, substrate preference and community structure of the biofilm developed on FO-SSA have not been well characterized. Herein, we investigated the community on FO-SSA using high-throughput sequencing of the 16S rRNA gene fragment in acetate-, starch-, glucose-, and livestock wastewater-fed MFCs. Furthermore, to analyze the effect of the anode material, the acetate-fed community formed on a common carbon-based electrode-carbon-cloth anode (CCA)-was examined for comparison. Substrate type influenced the power output of MFCs using FO-SSA; the highest electricity was generated using acetate as a substrate, followed by peptone, starch and glucose, and wastewater. Intensity of power generation using FO-SSA was related to the abundance of exoelectrogenic genera, namely Geobacter and Desulfuromonas, of the phylum Proteobacteria, which were detected at a higher frequency in acetate-fed communities than in communities fed with other substrates. Lactic acid bacteria (LAB)-Enterococcus and Carnobacterium-were predominant in starch- and glucose-fed communities, respectively. In the wastewater-fed community, members of phylum Planctomycetes were frequently detected (36.2%). Exoelectrogenic genera Geobacter and Desulfuromonas were also detected in glucose-, starch-, and wastewater-fed communities on FO-SSA, but with low frequency (0-3.2%); the lactate produced by Carnobacterium and Enterococcus in glucose- and starch-fed communities might affect exoelectrogenic bacterial growth, resulting in low power output by MFCs fed with these substrates. Furthermore, in the acetate-fed community on FO-SSA, Desulfuromonas was abundant (15.4%) and Geobacter had a minor proportion (0.7%), while in that on CCA, both Geobacter and Desulfuromonas were observed at similar frequencies (6.0-9.8%), indicating that anode material affects exoelectrogenic genus enrichment in anodic biofilm. Anodic community structure was dependent on both substrate and anode material. Although Desulfuromonas spp. are marine microorganisms, they were abundant in the acetate-fed community on FO-SSA, implying the presence of novel non-halophilic and exoelectrogenic species in this genus. Power generation using FO-SSA was positively related to the frequency of exoelectrogenic genera in the anodic community. Predominant LAB in saccharide-fed anodic biofilm caused low abundance of exoelectrogenic genera and consequent low power generation.

LibKiSAO: a Java library for Querying KiSAO.

PubMed

Zhukova, Anna; Adams, Richard; Laibe, Camille; Le Novère, Nicolas

2012-09-24

The Kinetic Simulation Algorithm Ontology (KiSAO) supplies information about existing algorithms available for the simulation of Systems Biology models, their characteristics, parameters and inter-relationships. KiSAO enables the unambiguous identification of algorithms from simulation descriptions. Information about analogous methods having similar characteristics and about algorithm parameters incorporated into KiSAO is desirable for simulation tools. To retrieve this information programmatically an application programming interface (API) for KiSAO is needed. We developed libKiSAO, a Java library to enable querying of the KiSA Ontology. It implements methods to retrieve information about simulation algorithms stored in KiSAO, their characteristics and parameters, and methods to query the algorithm hierarchy and search for similar algorithms providing comparable results for the same simulation set-up. Using libKiSAO, simulation tools can make logical inferences based on this knowledge and choose the most appropriate algorithm to perform a simulation. LibKiSAO also enables simulation tools to handle a wider range of simulation descriptions by determining which of the available methods are similar and can be used instead of the one indicated in the simulation description if that one is not implemented. LibKiSAO enables Java applications to easily access information about simulation algorithms, their characteristics and parameters stored in the OWL-encoded Kinetic Simulation Algorithm Ontology. LibKiSAO can be used by simulation description editors and simulation tools to improve reproducibility of computational simulation tasks and facilitate model re-use.

Clinical application of a multi-modal endoscope with fluorescent peptide in detection of colorectal neoplasia (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dai, Zhenzhen; Joshi, Bishnu P.; Gao, Zhenghong; Lee, Jeonghoon; Ghimire, Navin; Prabhu, Anoop; Wamsteker, Erik J.; Kwon, Richard S.; Elta, Grace H.; Appelman, Henry D.; Owens, Scott R.; Kuick, Rork; Turgeon, Kim K.; Wang, Thomas D.

2017-02-01

Early detection of precursor lesions for colorectal cancer can greatly improve survival. Pre-neoplasia can appear flat with conventional white light endoscopy. Sessile serrated adenomas (SSA) are precursor lesions found primarily in the proximal colon and frequently appear flat and indistinct. We performed a clinical study of n=37 patients using a multimodal endoscopy with a FITC-labeled peptide specific for SSA. Lesions were imaged with white light, reflectance and fluorescence. White light images were acquired before the peptide was applied and were used to help localize regions of abnormal tissues rightly. Co-registered fluorescence and reflectance images were combined to get ratio images thus the distance was corrected. We calculated the target/background ratio (T/B ratio) to quantify the images and found 2.3-fold greater fluorescence intensity for SSA compared with normal tissues. We found the T/B ratio for SSA to be significantly greater than that for normal colonic mucosa with 89.47% sensitivity and 91.67% specificity at the threshold of 1.22. An ROC curve for SSA and normal mucosa was also plotted with area under curve (AUC) of 0.93. The result also shows that SSA and adenoma are statistically significant and can be identified with 78.95% sensitivity and 90.48% specificity at the threshold of 1.66. An ROC curve was plotted with AUC of 0.88. Therefore, our result shows that the application of a multimodal endoscope with fluorescently labeled peptide can quantify images and works especially good for the detection of SSA which is a premalignant flat lesion conferring a high risk of subsequently leading to a colon cancer.

Changing pathological diagnosis from hyperplastic polyp to sessile serrated adenoma: systematic review and meta-analysis.

PubMed

Niv, Yaron

2017-12-01

The WHO published a new classification of colonic polyps in 2010, including the group of serrated polyps, which can be divided into hyperplastic polyps (HP), traditional serrated adenomas, and sessile serrated adenomas (SSA) or polyps. To assess the rate of re-diagnosis of HP to SSA and to look for possible predictors for changing the diagnosis. English Medical literature searches were performed for 'reassessment' OR 'reclassification' AND 'hyperplastic polyp' OR 'sessile serrated adenoma' till 31 January 2017. PRISMA guidelines for systematic reviews were followed. Studies that included a precise re-diagnosis of HP into SSA were included. We also looked for predictors of SSA diagnosis such as polyp location and size, patient sex and age, and synchronous advanced adenoma. Altogether, we found 220 eligible studies; 212 were excluded as they did not fulfill the inclusion criteria and we were left with eight studies including 2625 patients. The odds ratio for the number of polyps with changed pathological diagnosis from HP to SSA was 0.112 with 95% confidence interval (CI): 0.099-0.126 (P<0.0001) or 11.2%. Heterogeneity between studies was significant with Q=199.4, d.f. (Q)=9, P<0.0001, and I=95.486%. The odds ratio for changing the pathological diagnosis from HP to SSA for polyp proximal location and polyp size more than 5 mm were 4.401, 95% CI: 2.784-6.958, P<0.0001, and 8.336, 95% CI: 4.963-15.571, P<0.0001, respectively. Endoscopists and pathologists should be aware of the SSA diagnosis when finding HPs larger than 5 mm in the right colon. The diagnosis of HP in these cases should be reassessed by experienced gastrointestinal pathologists.

Preoperative octreotide therapy and surgery in acromegaly: associations between glucose homeostasis and treatment response.

PubMed

Helseth, R; Carlsen, S M; Bollerslev, J; Svartberg, J; Øksnes, M; Skeie, S; Fougner, S L

2016-02-01

In acromegaly, high GH/IGF-1 levels associate with abnormal glucose metabolism. Somatostatin analogs (SSAs) reduce GH and IGF-1 but inhibit insulin secretion. We studied glucose homeostasis in de novo patients with acromegaly and changes in glucose metabolism after treatment with SSA and surgery. In this post hoc analysis from a randomized controlled trial, 55 de novo patients with acromegaly, not using antidiabetic medication, were included. Before surgery, 26 patients received SSAs for 6 months. HbA1c, fasting glucose, and oral glucose tolerance test were performed at baseline, after SSA pretreatment and at 3 months postoperative. Area under curve of glucose (AUC-G) was calculated. Glucose homeostasis was compared to baseline levels of GH and IGF-1, change after SSA pretreatment, and remission both after SSA pretreatment and 3 months postoperative. In de novo patients, IGF-1/GH levels did not associate with baseline glucose parameters. After SSA pretreatment, changes in GH/IGF-1 correlated positively to change in HbA1c levels (both p < 0.03). HbA1c, fasting glucose, and AUC-G increased significantly during SSA pretreatment in patients not achieving hormonal control (all p < 0.05) but did not change significantly in patients with normalized hormone levels. At 3 months postoperative, HbA1c, fasting glucose, and AUC-G were significantly reduced in both cured and not cured patients (all p < 0.05). To conclude, in de novo patients with acromegaly, disease activity did not correlate with glucose homeostasis. Surgical treatment of acromegaly improved glucose metabolism in both cured and not cured patients, while SSA pretreatment led to deterioration in glucose homeostasis in patients not achieving biochemical control.

Adverse drug reaction reports for cardiometabolic drugs from sub-Saharan Africa: a study in VigiBase.

PubMed

Berhe, Derbew Fikadu; Juhlin, Kristina; Star, Kristina; Beyene, Kidanemariam G M; Dheda, Mukesh; Haaijer-Ruskamp, Flora M; Taxis, Katja; Mol, Peter G M

2015-06-01

Identifying key features in individual case safety reports (ICSR) of suspected adverse drug reactions (ADRs) with cardiometabolic drugs from sub-Saharan Africa (SSA) compared with reports from the rest of the world (RoW). Reports on suspected ADRs of cardiometabolic drugs (ATC: A10[antidiabetic], B01[antithrombotics] and C[cardiovascular]) were extracted from WHO Global database, VigiBase(®) (1992-2013). We used vigiPoint, a logarithmic odds ratios (log2 OR)-based method to study disproportional reporting between SSA and RoW. Case-defining features were considered relevant if the lower limit of the 99% CI > 0.5. In SSA, 3773 (9%) of reported ADRs were for cardiometabolic drugs, in RoW for 18%. Of these, 79% originated from South Africa and 81% were received after 2007. Most reports were for drugs acting on the renin-angiotensin system (36% SSA & 14% RoW). Compared with RoW, reports were more often sent for patients 18-44 years old (log2 OR 0.95 [99 CI 0.80; 1.09]) or with non-fatal outcome (log2 OR 1.16 [99 CI 1.10; 1.22]). Eight ADRs (cough, angioedema, lip swelling, face oedema, swollen tongue, throat irritation, drug ineffective and blood glucose abnormal) and seven drugs (enalapril, rosuvastatin, perindopril, vildagliptin, insulin glulisine, nifedipine and insulin lispro) were disproportionally more reported in SSA than in the RoW. 'In recent years, the number of adverse drug reactions (ADRs) reported in Sub-Saharan Africa (SSA) has sharply increased. The data showed the well-known population-based differential ADR profile of ACE inhibitors in the SSA population.' © 2015 John Wiley & Sons Ltd.

A Cloud-based, Open-Source, Command-and-Control Software Paradigm for Space Situational Awareness (SSA)

NASA Astrophysics Data System (ADS)

Melton, R.; Thomas, J.

With the rapid growth in the number of space actors, there has been a marked increase in the complexity and diversity of software systems utilized to support SSA target tracking, indication, warning, and collision avoidance. Historically, most SSA software has been constructed with "closed" proprietary code, which limits interoperability, inhibits the code transparency that some SSA customers need to develop domain expertise, and prevents the rapid injection of innovative concepts into these systems. Open-source aerospace software, a rapidly emerging, alternative trend in code development, is based on open collaboration, which has the potential to bring greater transparency, interoperability, flexibility, and reduced development costs. Open-source software is easily adaptable, geared to rapidly changing mission needs, and can generally be delivered at lower costs to meet mission requirements. This paper outlines Ball's COSMOS C2 system, a fully open-source, web-enabled, command-and-control software architecture which provides several unique capabilities to move the current legacy SSA software paradigm to an open source model that effectively enables pre- and post-launch asset command and control. Among the unique characteristics of COSMOS is the ease with which it can integrate with diverse hardware. This characteristic enables COSMOS to serve as the command-and-control platform for the full life-cycle development of SSA assets, from board test, to box test, to system integration and test, to on-orbit operations. The use of a modern scripting language, Ruby, also permits automated procedures to provide highly complex decision making for the tasking of SSA assets based on both telemetry data and data received from outside sources. Detailed logging enables quick anomaly detection and resolution. Integrated real-time and offline data graphing renders the visualization of the both ground and on-orbit assets simple and straightforward.

Tying Biological Activity to Changes in Sea Spray Aerosol Chemical Composition via Single Particle Analyses

NASA Astrophysics Data System (ADS)

Sultana, C. M.; Lee, C.; Collins, D. B.; Axson, J. L.; Laskina, O.; Grandquist, J. R.; Grassian, V. H.; Prather, K. A.

2014-12-01

In remote marine environments, sea spray aerosols (SSA) often represent the greatest aerosol burden, thus having significant impacts on direct radiative interactions and cloud processes. Previous studies have shown that SSA is a complex mixture of inorganic salts and an array of dissolved and particulate organic components. Enrichment of SSA organic content is often correlated to seawater chlorophyll concentrations, a measure of oceanic biological activity. As the physical and chemical properties of aerosols control their radiative effects, recent studies conducted by the Center for Aerosol Impacts on Climate and the Environment have endeavored to further elucidate the ties between marine biological activity and primary SSA chemical composition using highly time resolved single particle analyses. A series of experiments performed in the recently developed Marine Aerosol Reference Tank evaluated the effect of changing marine microbial populations on SSA chemical composition, which was monitored via an aerosol time-of-flight mass spectrometer and a variety of offline spectroscopic and microscopic techniques. Each experiment was initiated using unfiltered and untreated seawater, thus maintaining a high level of biogeochemical complexity. This study is the first of its kind to capture daily changes in the primary SSA mixing state over the growth and death of a natural phytoplankton bloom. Increases in organic aerosol types (0.4-3 μm), internally and externally mixed with sea salt, could not be correlated to chlorophyll concentrations. Maximum production of these populations occurred two to four days after the in vivo chlorophyll fluorescence peaked in intensity. This work is in contrast to the current paradigm of correlating SSA organic content to seawater chlorophyll concentration.

Australian Space Situational Awareness Capability Demonstrations

NASA Astrophysics Data System (ADS)

Morreale, B.; Bessell, T.; Rutten, M.; Cheung, B.

Australia is increasing its contribution to the global space situational awareness (SSA) problem by committing to acquire and operate SSA sensors. Over the last year, a series of collaborative SSA experiments have been undertaken to demonstrate the capabilities of Australian sensors. These experiments aimed to demonstrate how existing Australian sensors could perform in a surveillance of space role, prove passive radar’s capability to observe low earth orbit (LEO) satellites and perform SSA handoffs to optical sensors. The trials established a data sharing and communications protocol that bridged defence, academia, and industry partners. Geographically dispersed optical assets, including the Falcon telescope in Canberra, Raven telescopes in Exmouth (Western Australia) and Defence Science and Technology (DST) Telescopes in Adelaide (South Australia) collected on LEO satellites and established cueing protocols. The Murchison Widefield Array (MWA) located in Western Australia, demonstrated the capability of passive radar as an SSA asset after successfully observing LEO satellites based on reflected terrestrial radio signals. The combination of radar and optical SSA assets allows for the exploitation of each sensors unique advantages and locations across the Australian continent. This paper outlines the capabilities and diversity of Australian optical and radar sensors as demonstrated by field trials in 2016 and 2017. It suggests future potential for harnessing novel radar and optical integration techniques to supplement high-value assets such as the Space Surveillance Telescope as part of the Space Surveillance Network.

Lectin-Based Assay for Glycoform-Specific Detection of α2,6-sialylated Transferrin and Carcinoembryonic Antigen in Tissue and Body Fluid.

PubMed

Ito, Hiromi; Hoshi, Kyoka; Honda, Takashi; Hashimoto, Yasuhiro

2018-05-30

Antibodies are useful for detecting glycoprotein antigens, but a conventional antibody recognizes only a protein epitope rather than a glycan. Thus, glycan isoform detection generally requires time- and labor-consuming processes such as lectin affinity column chromatography followed by sandwich ELISA. We recently found antigen-antibody reactions that were inhibited by lectin binding to glycans on the glycoprotein antigen, leading to a convenient glycoform-specific assay. Indeed, Sambucus sieboldiana agglutinin (SSA) lectin, a binder to sialylα2,6galactose residue, inhibited antibody binding to α2,6-sialylated transferrin (Tf) (SSA inhibition). SSA inhibition was not observed with other glycoforms, such as periodate-treated, sialidase-treated and sialidase/galactosidase-treated Tf, suggesting that the assay was glycoform-specific. SSA inhibition was also applicable for visualizing localization of α2,6-sialylated-Tf in a liver section. This is the first immunohistochemical demonstration of glycoform localization in a tissue section. SSA inhibition was utilized for establishing ELISA to quantify α2,6-sialylated carcinoembryonic antigen (CEA), a marker for various cancers. In addition, α2,6-sialylated-CEA was visualized in a colonic adenocarcinoma section by SSA inhibition. The method would further be applicable to a simple and rapid estimation of other α2,6-sialylated glycoproteins and have a potential aid to histopathological diagnosis.

Somatostatin analogue-induced pancreatic exocrine insufficiency in patients with neuroendocrine tumours: results of a prospective observational study.

PubMed

Lamarca, Angela; McCallum, Lynne; Nuttall, Christina; Barriuso, Jorge; Backen, Alison; Frizziero, Melissa; Leon, Rebecca; Mansoor, Was; McNamara, Mairéad G; Hubner, Richard A; Valle, Juan W

2018-06-20

Background Patients with advanced well-differentiated neuroendocrine tumours(Wd-NETs) are commonly treated with somatostatin analogues(SSAs). Some patients may develop SSA-related side effects such as pancreatic exocrine insufficiency(PEI). Methods In this single-institution, prospective, observational study, the frequency of SSA-induced PEI in 50 sequential patients with advanced Wd-NETs treated with SSAs was investigated. Toxicity was assessed monthly and faecal elastase-1 (FE1) and quality of life (QoL) were assessed 3-monthly. Results The median age was 65.8 years, 58% were male and the majority (92%) of patients had metastatic disease; patients received 4-weekly long acting octreotide (60%) or lanreotide (40%). Twelve patients (24%) developed SSA-related PEI after a median of 2.9 months from SSA initiation; FE1 was a reliable screening tool, especially in symptomatic patients (risk ratio 8.25 (95% confidence interval 1.15-59.01)). Most of these patients (11/12; 92%) required PERT. Other SSA-related adverse events (any grade) included flatulence (50%), abdominal pain (32%), diarrhoea (30%) and fatigue (20%). Development of PEI did not significantly worsen overall QoL, however gastrointestinal symptoms and diarrhoea were increased. Conclusion This study demonstrated that PEI occurs at a higher rate than previously reported; clinicians need to diagnose and treat this SSA-related adverse-event which occurs in 1 in 4 patients with Wd-NETs treated with SSAs.

Endoscopic Features of Mucous Cap Polyps: A Way to Predict Serrated Polyps.

PubMed

Moy, Brian T; Forouhar, Faripour; Kuo, Chia-Ling; Devers, Thomas J

2018-04-27

The aims of the study were to identify whether a mucous-cap predicts the presence of serrated polyps, and to determine whether additional endoscopic findings predict the presence of a sessile serrated adenomas/polyp (SSA/P). We analyzed 147 mucous-capped polyps with corresponding histology, during 2011-2014. Eight endoscopic features (presence of borders, elevation, rim of debris, location in the colon, size ≥10 mm, varicose vessels, nodularity, and alteration in mucosal folds) of mucous-capped polyps were examined to see if they can predict SSA/Ps. A total of 86% (n=126) of mucous-capped polyps were from the right sided serrated pathway (right-sided hyperplastic [n=83], SSA/Ps [n=43], traditional serrated adenoma [n=1]), 10% (n=15) were left-sided hyperplastic polyps, and 3% (n=5) were from the adenoma-carcinoma sequence. The presence of a mucous cap combined with varicose vessels was the only significant predictor for SSA/Ps. The other seven characteristics were not found to be statistically significant for SSA/Ps, although location in the colon and the presence of nodularity trended towards significance. Our study suggests that mucous-capped polyps have high predictability for being a part of the serrated pathway. Gastroenterologists should be alert for a mucous-capped polyp with varicose veins, as these lesions have a higher risk of SSA/P.

The location of a disease-associated polymorphism and genomic structure of the human 52-kDa Ro/SSA locus (SSA1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsugu, H.; Horowitz, R.; Gibson, N.

1994-12-01

Sera from approximately 30% of patients with systemic lupus erythematosus (SLE) contain high titers of autoantibodies that bind to the 52-kDa Ro/SSA protein. We previously detected polymorphisms in the 52-kDa Ro/SSA gene (SSA1) with restriction enzymes, one of which is strongly associated with the presence of SLE (P < 0.0005) in African Americans. A higher disease frequency and more severe forms of the disease are commonly noted among these female patients. To determine the location and nature of this polymorphism, we obtained two clones that span 8.5 kb of the 52-kDa Ro/SSA locus including its upstream regulatory region. Six exonsmore » were identified, and their nucleotide sequences plus adjacent noncoding regions were determined. No differences were found between these exons and the coding region of one of the reported cDNAs. The disease-associated polymorphic site suggested by a restriction enzyme map and confirmed by DNA amplification and nucleotide sequencing was present upstream of exon 1. This polymorphism may be a genetic marker for a disease-related variation in the coding region for the protein or in the upstream regulatory region of this gene. Although this RFLP is present in Japanese, it is not associated with lupus in this race. 41 refs., 4 figs., 2 tabs.« less

Can sub-Saharan Africa feed itself?

PubMed Central

van Ittersum, Martin K.; van Bussel, Lenny G. J.; Wolf, Joost; Grassini, Patricio; van Wart, Justin; Guilpart, Nicolas; Claessens, Lieven; de Groot, Hugo; Wiebe, Keith; Yang, Haishun; Boogaard, Hendrik; van Oort, Pepijn A. J.; van Loon, Marloes P.; Saito, Kazuki; Adimo, Ochieng; Adjei-Nsiah, Samuel; Agali, Alhassane; Bala, Abdullahi; Chikowo, Regis; Kaizzi, Kayuki; Kouressy, Mamoutou; Makoi, Joachim H. J. R.; Ouattara, Korodjouma; Tesfaye, Kindie; Cassman, Kenneth G.

2016-01-01

Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub-Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase in food demand by 2050 can be met through closing the gap between current farm yield and yield potential on existing cropland. Here, however, we estimate it will not be feasible to meet future SSA cereal demand on existing production area by yield gap closure alone. Our agronomically robust yield gap analysis for 10 countries in SSA using location-specific data and a spatial upscaling approach reveals that, in addition to yield gap closure, other more complex and uncertain components of intensification are also needed, i.e., increasing cropping intensity (the number of crops grown per 12 mo on the same field) and sustainable expansion of irrigated production area. If intensification is not successful and massive cropland land expansion is to be avoided, SSA will depend much more on imports of cereals than it does today. PMID:27956604

Can sub-Saharan Africa feed itself?

PubMed

van Ittersum, Martin K; van Bussel, Lenny G J; Wolf, Joost; Grassini, Patricio; van Wart, Justin; Guilpart, Nicolas; Claessens, Lieven; de Groot, Hugo; Wiebe, Keith; Mason-D'Croz, Daniel; Yang, Haishun; Boogaard, Hendrik; van Oort, Pepijn A J; van Loon, Marloes P; Saito, Kazuki; Adimo, Ochieng; Adjei-Nsiah, Samuel; Agali, Alhassane; Bala, Abdullahi; Chikowo, Regis; Kaizzi, Kayuki; Kouressy, Mamoutou; Makoi, Joachim H J R; Ouattara, Korodjouma; Tesfaye, Kindie; Cassman, Kenneth G

2016-12-27

Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub-Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase in food demand by 2050 can be met through closing the gap between current farm yield and yield potential on existing cropland. Here, however, we estimate it will not be feasible to meet future SSA cereal demand on existing production area by yield gap closure alone. Our agronomically robust yield gap analysis for 10 countries in SSA using location-specific data and a spatial upscaling approach reveals that, in addition to yield gap closure, other more complex and uncertain components of intensification are also needed, i.e., increasing cropping intensity (the number of crops grown per 12 mo on the same field) and sustainable expansion of irrigated production area. If intensification is not successful and massive cropland land expansion is to be avoided, SSA will depend much more on imports of cereals than it does today.

An adaptive process-based cloud infrastructure for space situational awareness applications

NASA Astrophysics Data System (ADS)

Liu, Bingwei; Chen, Yu; Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik; Rubin, Bruce

2014-06-01

Space situational awareness (SSA) and defense space control capabilities are top priorities for groups that own or operate man-made spacecraft. Also, with the growing amount of space debris, there is an increase in demand for contextual understanding that necessitates the capability of collecting and processing a vast amount sensor data. Cloud computing, which features scalable and flexible storage and computing services, has been recognized as an ideal candidate that can meet the large data contextual challenges as needed by SSA. Cloud computing consists of physical service providers and middleware virtual machines together with infrastructure, platform, and software as service (IaaS, PaaS, SaaS) models. However, the typical Virtual Machine (VM) abstraction is on a per operating systems basis, which is at too low-level and limits the flexibility of a mission application architecture. In responding to this technical challenge, a novel adaptive process based cloud infrastructure for SSA applications is proposed in this paper. In addition, the details for the design rationale and a prototype is further examined. The SSA Cloud (SSAC) conceptual capability will potentially support space situation monitoring and tracking, object identification, and threat assessment. Lastly, the benefits of a more granular and flexible cloud computing resources allocation are illustrated for data processing and implementation considerations within a representative SSA system environment. We show that the container-based virtualization performs better than hypervisor-based virtualization technology in an SSA scenario.

Relationship between the specific surface area of rust and the electrochemical behavior of rusted steel in a wet-dry acid corrosion environment

NASA Astrophysics Data System (ADS)

Liu, Wei; Zhao, Qing-he; Li, Shuan-zhu

2017-01-01

The relationship between the specific surface area (SSA) of rust and the electrochemical behavior of rusted steel under wet-dry acid corrosion conditions was investigated. The results showed that the corrosion current density first increased and then decreased with increasing SSA of the rust during the corrosion process. The structure of the rust changed from single-layer to double-layer, and the γ-FeOOH content decreased in the inner layer of the rust with increasing corrosion time; by contrast, the γ-FeOOH content in the outer layer was constant. When the SSA of the rust was lower than the critical SSA corresponding to the relative humidity during the drying period, condensed water in the micropores of the rust could evaporate, which prompted the diffusion of O2 into the rust and the following formation process of γ-FeOOH, leading to an increase of corrosion current density with increasing corrosion time. However, when the SSA of the rust reached or exceeded the critical SSA, condensate water in the micro-pores of the inner layer of the rust could not evaporate which inhibited the diffusion of O2 and decreased the γ-FeOOH content in the inner rust, leading to a decrease of corrosion current density with increasing corrosion time.

Small and large particle limits of single scattering albedo for homogeneous, spherical particles

NASA Astrophysics Data System (ADS)

Moosmüller, H.; Sorensen, C. M.

2018-01-01

The aerosol single scattering albedo (SSA) is the dominant intensive particle parameter determining aerosols direct radiative forcing. For homogeneous spherical particles and a complex refractive index independent of wavelength, the SSA is solely dependent on size parameter (ratio of particle circumference and wavelength) and complex refractive index of the particle. Here, we explore this dependency for the small and large particle limits with size parameters much smaller and much larger than one. We show that in the small particle limit of Rayleigh scattering, a novel, generalized size parameter can be introduced that unifies the SSA dependence on particle size parameter independent of complex refractive index. In the large particle limit, SSA decreases with increasing product of imaginary part of the refractive index and size parameter, another generalized parameter, until this product becomes about one, then stays fairly constant until the imaginary part of the refractive index becomes comparable with the real part minus one. Beyond this point, particles start to acquire metallic character and SSA quickly increases with the imaginary part of the refractive index and approaches one.

Sexual Orientation Self-Concept Ambiguity: Scale Adaptation and Validation.

PubMed

Talley, Amelia E; Stevens, Jordan E

2017-07-01

The current article describes the adaptation of a measure of sexual orientation self-concept ambiguity (SSA) from an existing measure of general self-concept clarity. Latent "trait" scores of SSA reflect the extent to which a person's beliefs about their own sexual orientation are perceived as inconsistent, unreliable, or incongruent. Sexual minority and heterosexual women ( n = 348), ages 18 to 30, completed a cross-sectional survey. Categorical confirmatory factor analysis guided the selection of items to form a 10-item, self-report measure of SSA. In the current report, we also examine (a) reliability of the 10-item scale score, (b) measurement invariance based on respondents' sexual identity status and age group, and (c) correlations with preexisting surveys that purport to measure similar constructs and theoretical correlates. Evidence for internal reliability, measurement invariance (based on respondent sex), and convergent validity was also investigated in an independent, validation sample. The lowest SSA scores were reported by women who self-ascribed an exclusively heterosexual or exclusively lesbian/gay sexual identity, whereas those who reported a bisexual, mostly lesbian/gay, or mostly heterosexual identity, reported relatively higher SSA scores.

Serrated lesions of the appendix: a morphologic and immunohistochemical appraisal.

PubMed

Bellizzi, Andrew M; Rock, Jonathan; Marsh, William L; Frankel, Wendy L

2010-04-01

We performed a histologic and immunohistochemical assessment of 53 noninvasive appendiceal epithelial proliferations, appropriating terminology and using markers shown useful in differentiating serrated colorectal polyps. These were classified as hyperplastic polyp (HP), sessile serrated adenoma (SSA), mixed serrated and adenomatous lesion (MSAL), mucinous cystadenoma (MCA), or conventional adenoma (CAD). Immunohistochemical analysis for cytokeratin (CK) 20, Ki-67, MUC6, and beta-catenin was performed. Diagnoses were as follows: HP, 6; SSA, 12; HP vs SSA, 3; MSAL, 16; MCA, 14; and CAD, 2. All HPs showed expanded (beyond surface) CK20 and expanded or normal (base) Ki-67; 1 was MUC6+. Most SSAs and MSALs were CK20-expanded or expanded with random expression in deep crypts (Ex/I) and Ki-67-expanded, Ex/I (expanded with asymmetry), or normal. All SSAs and 8 of 16 MSALs were MUC6+. CADs were CK20-Ex/I, Ki-67-Ex, and MUC6-; 1 showed nuclear beta-catenin expression. Serrated appendiceal lesions can be categorized using colorectal terminology. MUC6 is associated with SSA morphologic features. Similar immunohistochemical patterns in SSA and MSAL suggest a link between these lesions.

Spectral Analysis within the Virtual Observatory: The GAVO Service TheoSSA

NASA Astrophysics Data System (ADS)

Ringat, E.

2012-03-01

In the last decade, numerous Virtual Observatory organizations were established. One of these is the German Astrophysical Virtual Observatory (GAVO) that e.g. provides access to spectral energy distributions via the service TheoSSA. In a pilot phase, these are based on the Tübingen NLTE Model-Atmosphere Package (TMAP) and suitable for hot, compact stars. We demonstrate the power of TheoSSA in an application to the sdOB primary of AA Doradus by comparison with a “classical” spectral analysis.

Steps Toward an EOS-Era Aerosol Type Climatology

NASA Technical Reports Server (NTRS)

Kahn, Ralph A.

2012-01-01

We still have a way to go to develop a global climatology of aerosol type from the EOS-era satellite data record that currently spans more than 12 years of observations. We have demonstrated the ability to retrieve aerosol type regionally, providing a classification based on the combined constraints on particle size, shape, and single-scattering albedo (SSA) from the MISR instrument. Under good but not necessarily ideal conditions, the MISR data can distinguish three-to-five size bins, two-to-four bins in SSA, and spherical vs. non-spherical particles. However, retrieval sensitivity varies enormously with scene conditions. So, for example, there is less information about aerosol type when the mid-visible aerosol optical depth (AOD) is less that about 0.15 or 0.2, or when the range of scattering angles observed is reduced by solar geometry, even though the quality of the AOD retrieval itself is much less sensitive to these factors. This presentation will review a series of studies aimed at assessing the capabilities, as well as the limitations, of MISR aerosol type retrievals involving wildfire smoke, desert dust, volcanic ash, and urban pollution, in specific cases where suborbital validation data are available. A synthesis of results, planned upgrades to the MISR Standard aerosol algorithm to improve aerosol type retrievals, and steps toward the development of an aerosol type quality flag for the Standard product, will also be covered.

MISR Global Aerosol Product Assessment by Comparison with AERONET

NASA Technical Reports Server (NTRS)

Kahn, Ralph A.; Gaitley, Barbara J.; Garay, Michael J.; Diner, David J.; Eck, Thomas F.; Smirnov, Alexander; Holben, Brent N.

2010-01-01

A statistical approach is used to assess the quality of the MISR Version 22 (V22) aerosol products. Aerosol Optical Depth (AOD) retrieval results are improved relative to the early post- launch values reported by Kahn et al. [2005a], varying with particle type category. Overall, about 70% to 75% of MISR AOD retrievals fall within 0.05 or 20% AOD of the paired validation data, and about 50% to 55% are within 0.03 or 10% AOD, except at sites where dust, or mixed dust and smoke, are commonly found. Retrieved particle microphysical properties amount to categorical values, such as three groupings in size: "small," "medium," and "large." For particle size, ground-based AERONET sun photometer Angstrom Exponents are used to assess statistically the corresponding MISR values, which are interpreted in terms of retrieved size categories. Coincident Single-Scattering Albedo (SSA) and fraction AOD spherical data are too limited for statistical validation. V22 distinguishes two or three size bins, depending on aerosol type, and about two bins in SSA (absorbing vs. non-absorbing), as well as spherical vs. non-spherical particles, under good retrieval conditions. Particle type sensitivity varies considerably with conditions, and is diminished for mid-visible AOD below about 0.15 or 0.2. Based on these results, specific algorithm upgrades are proposed, and are being investigated by the MISR team for possible implementation in future versions of the product.

Evaluating Options for Civil Space Situational Awareness (SSA)

NASA Astrophysics Data System (ADS)

Lal, B.; Carioscia, S. A.

In recent years, the number of active satellites and human-made orbital space debris has increased dramatically. An expansion of activities in space, as is currently being proposed by many commercial and international entities, is expected to further exacerbate this challenge. The 18th Space Control Squadron under the Department of Defense (DOD) United States Strategic Command provides space situational awareness (SSA) services to users outside the national security community at no cost. International and commercial users demand better SSA service than is currently feasible, and the demand comes at a time when DOD is under pressure to better prepare for and respond to growing space-based threats to national security. Concerned about the possibility of overextending across conflicting missions in a fiscally constrained environment, some DOD officials have publicly noted a desire to move SSA services not related to national security out of DOD purview. Responding to a request from the Federal Aviation Administration (FAA) Office of Commercial Space Transportation (AST), researchers at the Science and Technology Policy Institute (STPI) identified and evaluated potential approaches for providing SSA services for civil and commercial operations in space. In this paper, we summarize the report [1] and present the pros and cons of four approaches to the provision of civil SSA services in the United States: (1) maintaining status quo through continued provision by DOD; (2) provision by a civil government entity; (3) industry self-provision; and (4) provision by an international organization. Within the second approach, assuming the provision of SSA by a civil agency, STPI further identified and discussed four options: (1) civil agency service capability embedded within DOD; (2) independent civil service capability, using DOD software and systems; (3) independent civil service capability, using commercial software and systems; and (4) the government certifies non-governmental entities (NGEs) to provide service capability. All of these approaches keep military and national security SSA services within DOD. Selecting which approach or option to proceed with depends on the determination of the role of government in the domain as well as consideration of other policy challenges.

Comparison of AOD, AAOD and column single scattering albedo from AERONET retrievals and in situ profiling measurements

NASA Astrophysics Data System (ADS)

Andrews, Elisabeth; Ogren, John A.; Kinne, Stefan; Samset, Bjorn

2017-05-01

Here we present new results comparing aerosol optical depth (AOD), aerosol absorption optical depth (AAOD) and column single scattering albedo (SSA) obtained from in situ vertical profile measurements with AERONET ground-based remote sensing from two rural, continental sites in the US. The profiles are closely matched in time (within ±3 h) and space (within 15 km) with the AERONET retrievals. We have used Level 1.5 inversion retrievals when there was a valid Level 2 almucantar retrieval in order to be able to compare AAOD and column SSA below AERONET's recommended loading constraint (AOD > 0.4 at 440 nm). While there is reasonable agreement for the AOD comparisons, the direct comparisons of in situ-derived to AERONET-retrieved AAOD (or SSA) reveal that AERONET retrievals yield higher aerosol absorption than obtained from the in situ profiles for the low aerosol optical depth conditions prevalent at the two study sites. However, it should be noted that the majority of SSA comparisons for AOD440 > 0.2 are, nonetheless, within the reported SSA uncertainty bounds. The observation that, relative to in situ measurements, AERONET inversions exhibit increased absorption potential at low AOD values is generally consistent with other published AERONET-in situ comparisons across a range of locations, atmospheric conditions and AOD values. This systematic difference in the comparisons suggests a bias in one or both of the methods, but we cannot assess whether the AERONET retrievals are biased towards high absorption or the in situ measurements are biased low. Based on the discrepancy between the AERONET and in situ values, we conclude that scaling modeled black carbon concentrations upwards to match AERONET retrievals of AAOD should be approached with caution as it may lead to aerosol absorption overestimates in regions of low AOD. Both AERONET retrievals and in situ measurements suggest there is a systematic relationship between SSA and aerosol amount (AOD or aerosol light scattering) - specifically that SSA decreases at lower aerosol loading. This implies that the fairly common assumption that AERONET SSA values retrieved at high-AOD conditions can be used to obtain AAOD at low-AOD conditions may not be valid.

Space Object Maneuver Detection Algorithms Using TLE Data

NASA Astrophysics Data System (ADS)

Pittelkau, M.

2016-09-01

An important aspect of Space Situational Awareness (SSA) is detection of deliberate and accidental orbit changes of space objects. Although space surveillance systems detect orbit maneuvers within their tracking algorithms, maneuver data are not readily disseminated for general use. However, two-line element (TLE) data is available and can be used to detect maneuvers of space objects. This work is an attempt to improve upon existing TLE-based maneuver detection algorithms. Three adaptive maneuver detection algorithms are developed and evaluated: The first is a fading-memory Kalman filter, which is equivalent to the sliding-window least-squares polynomial fit, but computationally more efficient and adaptive to the noise in the TLE data. The second algorithm is based on a sample cumulative distribution function (CDF) computed from a histogram of the magnitude-squared |V|2 of change-in-velocity vectors (V), which is computed from the TLE data. A maneuver detection threshold is computed from the median estimated from the CDF, or from the CDF and a specified probability of false alarm. The third algorithm is a median filter. The median filter is the simplest of a class of nonlinear filters called order statistics filters, which is within the theory of robust statistics. The output of the median filter is practically insensitive to outliers, or large maneuvers. The median of the |V|2 data is proportional to the variance of the V, so the variance is estimated from the output of the median filter. A maneuver is detected when the input data exceeds a constant times the estimated variance.

The Potsdam Parallel Ice Sheet Model (PISM-PIK) - Part 1: Model description

NASA Astrophysics Data System (ADS)

Winkelmann, R.; Martin, M. A.; Haseloff, M.; Albrecht, T.; Bueler, E.; Khroulev, C.; Levermann, A.

2010-08-01

We present the Potsdam Parallel Ice Sheet Model (PISM-PIK), developed at the Potsdam Institute for Climate Impact Research to be used for simulations of large-scale ice sheet-shelf systems. It is derived from the Parallel Ice Sheet Model (Bueler and Brown, 2009). Velocities are calculated by superposition of two shallow stress balance approximations within the entire ice covered region: the shallow ice approximation (SIA) is dominant in grounded regions and accounts for shear deformation parallel to the geoid. The plug-flow type shallow shelf approximation (SSA) dominates the velocity field in ice shelf regions and serves as a basal sliding velocity in grounded regions. Ice streams naturally emerge through this approach and can be identified diagnostically as regions with a significant contribution of membrane stresses to the local momentum balance. All lateral boundaries in PISM-PIK are free to evolve, including the grounding line and ice fronts. Ice shelf margins in particular are modeled using Neumann boundary conditions for the SSA equations, reflecting a hydrostatic stress imbalance along the vertical calving face. The ice front position is modeled using a subgrid scale representation of calving front motion (Albrecht et al., 2010) and a physically motivated dynamic calving law based on horizontal spreading rates. The model is validated within the Marine Ice Sheet Model Intercomparison Project (MISMIP) and is used for a dynamic equilibrium simulation of Antarctica under present-day conditions in the second part of this paper (Martin et al., 2010).

Comparative Toxicity of Simulated Smog Atmospheres in ...

EPA Pesticide Factsheets

Effects of complex regional multipollutant mixtures on disease expression in susceptible populations are dependent on multiple exposure and susceptibility factors. Differing profiles of ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM), which are key components of smog, and other hazardous pollutants may develop as a result of regional-specific geographic and urban environment characteristics. We investigated the pulmonary effects of two smog mixtures with different compositions in a mouse model of allergic airway disease to determine which source profile had the greatest impact on pulmonary endpoints. A hydrocarbon mixture was combined with NO gas in the presence of UV light in a controlled setting. Simulated smog atmosphere 1 (SSA-1) consisted of concentrations of 1070 µg/m3 secondary organic aerosol (SOA), 0.104 ppm O3, and 0.252 ppm NO2. SSA-2 consisted of a starting concentration of 53 µg/m3 SOA, 0.376 ppm O3, and 0.617 ppm NO2. An increased aerosol concentration was noted in the exposure chamber. Healthy and house dust mite (HDM)-sensitized (allergic) female BALB/cJ mice were exposed 4 hr/day for 1 or 5 days to either smog mixture or clean air. Two days after HDM challenge, airway mechanics were tested in anesthetized ventilated mice. Following methacholine aerosol challenge, increased airway resistance and elastance and a decrease in lung compliance were consistently observed in air- and smog-exposed HDM-allergic groups compared with non-a

Perturbations of the optical properties of mineral dust particles by mixing with black carbon: a numerical simulation study

DOE PAGES

Scarnato, B. V.; China, S.; Nielsen, K.; ...

2015-06-25

Field observations show that individual aerosol particles are a complex mixture of a wide variety of species, reflecting different sources and physico-chemical transformations. The impacts of individual aerosol morphology and mixing characteristics on the Earth system are not yet fully understood. Here we present a sensitivity study on climate-relevant aerosols optical properties to various approximations. Based on aerosol samples collected in various geographical locations, we have observationally constrained size, morphology and mixing, and accordingly simulated, using the discrete dipole approximation model (DDSCAT), optical properties of three aerosols types: (1) bare black carbon (BC) aggregates, (2) bare mineral dust, and (3)more » an internal mixture of a BC aggregate laying on top of a mineral dust particle, also referred to as polluted dust. DDSCAT predicts optical properties and their spectral dependence consistently with observations for all the studied cases. Predicted values of mass absorption, scattering and extinction coefficients (MAC, MSC, MEC) for bare BC show a weak dependence on the BC aggregate size, while the asymmetry parameter ( g) shows the opposite behavior. The simulated optical properties of bare mineral dust present a large variability depending on the modeled dust shape, confirming the limited range of applicability of spheroids over different types and size of mineral dust aerosols, in agreement with previous modeling studies. The polluted dust cases show a strong decrease in MAC values with the increase in dust particle size (for the same BC size) and an increase of the single scattering albedo (SSA). Furthermore, particles with a radius between 180 and 300 nm are characterized by a decrease in SSA values compared to bare dust, in agreement with field observations.This paper demonstrates that observationally constrained DDSCAT simulations allow one to better understand the variability of the measured aerosol optical properties in ambient air and to define benchmark biases due to different approximations in aerosol parametrization.« less

78 FR 16753 - Service Delivery Plan; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-18

... the first sentence after the words, ``Service Delivery Plan (SDP) insert http://www.ssa.gov/open/SDP... http://ssa.gov/asp/plan-2013-2016.pdf . Paul Kryglik, Director, Office of Regulations, Social Security...

BOREAS HYD-1 Under-Canopy Precipitation Data

NASA Technical Reports Server (NTRS)

Cuenca, Richard H.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Kelly, Shaun; Stangel, David E.; Smith, David E. (Technical Monitor)

2000-01-01

Under-canopy precipitation measurements were made by the BOREAS HYD-1 science team in 1994, 1995, and 1996 at various flux tower sites in the NSA and SSA. In 1994, these data were collected at the NSA-OJP, NSA-YJP, SSA-OJP, and SSA-YJP sites. Starting in 1995 and ending in 1997, data were collected at the NSA-OBS, NSA-OJP, NSA-YJP, and SSA-OA. These data were collected to support HYD-01 research by measuring the amount of water that falls through the canopy and is intercepted by the ground or moss. These data coincide with volumetric soil moisture measurements made by HYD-01. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Surveillance application using patten recognition software at the EBR-II Reactor Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, D.L.

1992-01-01

The System State Analyzer (SSA) is a software based pattern recognition system. For the past several year this system has been used at Argonne National Laboratory's Experimental Breeder Reactor 2 (EBR-2) reactor for detection of degradation and other abnormalities in plant systems. Currently there are two versions of the SSA being used at EBR-2. One version of SSA is used for daily surveillance and trending of the reactor delta-T and startups of the reactor. Another version of the SSA is the QSSA which is used to monitor individual systems of the reactor such as the Secondary Sodium System, Secondary Sodiummore » Pumps, and Steam Generator. This system has been able to detect problems such as signals being affected by temperature variations due to a failing temperature controller.« less

Surveillance application using patten recognition software at the EBR-II Reactor Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, D.L.

1992-05-01

The System State Analyzer (SSA) is a software based pattern recognition system. For the past several year this system has been used at Argonne National Laboratory`s Experimental Breeder Reactor 2 (EBR-2) reactor for detection of degradation and other abnormalities in plant systems. Currently there are two versions of the SSA being used at EBR-2. One version of SSA is used for daily surveillance and trending of the reactor delta-T and startups of the reactor. Another version of the SSA is the QSSA which is used to monitor individual systems of the reactor such as the Secondary Sodium System, Secondary Sodiummore » Pumps, and Steam Generator. This system has been able to detect problems such as signals being affected by temperature variations due to a failing temperature controller.« less

Improving maternal healthcare utilisation in sub-Saharan Africa through micro-finance.

PubMed

Abekah-Nkrumah, Gordon; Abor, Patience Aseweh; Abor, Joshua; Adjasi, Charles K D

2011-01-01

This paper aims to examine links between women's access to micro-finance and how they use maternal healthcare services in sub-Saharan Africa (SSA). The authors use theoretical and empirical literature to propose a framework to sustain and improve women's access to maternal healthcare services through micro-financing. It is found that improved access to micro-finance by women, combined with education may enhance maternal health service uptake. The paper does not consider empirical data in the analysis. The authors advocate empirically testing the framework proposed in other SSA countries. It is important to empower women by facilitating their access to education and micro-finance. This has implications for improving maternal healthcare utilization in SSA. The paper moves beyond poor access to maternal health services in SSA and proposes a framework for providing sustainable solutions.

Does Sexual Self-Concept Ambiguity Moderate Relations Among Perceived Peer Norms for Alcohol Use, Alcohol-Dependence Symptomatology, and HIV Risk-Taking Behavior?

PubMed Central

Talley, Amelia E; Brown, Jennifer L; Stevens, Angela K; Littlefield, Andrew K

2014-01-01

Objective: The current study examines the relation between peer descriptive norms for alcohol involvement and alcohol-dependence symptomatology and whether this relation differs as a function of sexual self-concept ambiguity (SSA). This study also examines the associations among peer descriptive norms for alcohol involvement, alcohol-dependence symptomatology, and lifetime HIV risk-taking behavior and how these relations are influenced by SSA. Method: Women between ages 18 and 30 years (N = 351; M = 20.96, SD = 2.92) completed an online survey assessing sexual self-concept, peer descriptive norms, alcohol-dependence symptomatology, and HIV risk-taking behaviors. Structural equation modeling was used to test hypotheses of interest. Results: There was a significant latent variable interaction between SSA and descriptive norms for peer alcohol use. There was a stronger positive relationship between peer descriptive norms for alcohol and alcohol-dependence symptomatology when SSA was higher compared with when SSA was lower. Both latent variables exhibited positive simple associations with alcohol-dependence symptoms. Peer descriptive norms for alcohol involvement directly and indirectly influenced HIV risk-taking behaviors, and the indirect influence was conditional based on SSA. Conclusions: The current findings illustrate complex, nuanced associations between perceived norms, identity-related self-concepts, and risky health behaviors from various domains. Future intervention efforts may be warranted to address both problem alcohol use and HIV-risk engagement among individuals with greater sexual self-concept ambiguity. PMID:25343661

Streptomyces capitiformicae sp. nov., a novel actinomycete producing angucyclinone antibiotics isolated from the head of Camponotus japonicus Mayr.

PubMed

Jiang, Shanwen; Piao, Chenyu; Yu, Yang; Cao, Peng; Li, Chenxu; Yang, Fan; Li, Mutong; Xiang, Wensheng; Liu, Chongxi

2018-01-01

A novel actinomycete, designated strain 1H-SSA4 T , was isolated from the head of an ant (Camponotus japonicus Mayr) and was found to produce angucyclinone antibiotics. A polyphasic approach was used to determine the taxonomic status of strain 1H-SSA4 T . The DNA G+C content of the draft genome sequence, consisting of 11.4 Mbp, was 70.0 mol%. 16S rRNA gene sequence similarity studies showed that strain 1H-SSA4 T belongs to the genus Streptomyces with the highest sequence similarity to Streptomyces hygroscopicus subsp. ossamyceticus NBRC 13983 T (98.9 %), and phylogenetically clustered with this species, Streptomyces torulosus LMG 20305 T (98.8 %), Streptomyces ipomoeae NBRC 13050 T (98.5 %) and Streptomyces decoyicus NRRL 2666 T (98.4 %). The morphological and chemotaxonomic properties of the strain were also consistent with those members of the genus Streptomyces. A combination of DNA-DNA hybridization experiments and phenotypic tests were carried out between strain 1H-SSA4 T and the above-mentioned strains, which further clarified their relatedness and demonstrated that strain 1H-SSA4 T could be distinguished from these strains. Therefore, the strain is concluded to represent a novel species of the genus Streptomyces, for which the name Streptomyces capitiformicae sp. nov. is proposed. The type strain is 1H-SSA4 T (=CGMCC 4.7403 T =DSM 104537 T ).

Production characteristics of lettuce Lactuca sativa L. in the frame of the first crop tests in the Higher Plant Chamber integrated into the MELiSSA Pilot Plant

NASA Astrophysics Data System (ADS)

Tikhomirova, Natalia; Lawson, Jamie; Stasiak, Michael; Dixon, Mike; Paille, Christel; Peiro, Enrique; Fossen, Arnaud; Godia, Francesc

Micro-Ecological Life Support System Alternative (MELiSSA) is an artificial closed ecosystem that is considered a tool for the development of a bioregenerative life support system for manned space missions. One of the five compartments of MELiSSA loop -Higher Plant Chamber was recently integrated into the MELiSSA Pilot Plant facility at Universitat Aut`noma deo Barcelona. The main contributions expected by integration of this photosynthetic compartment are oxygen, water, vegetable food production and CO2 consumption. Production characteristics of Lactuca sativa L., as a MELiSSA candidate crop, were investigated in this work in the first crop experiments in the MELiSSA Pilot Plant facility. The plants were grown in batch culture and totaled 100 plants with a growing area 5 m long and 1 m wide in a sealed controlled environment. Several replicates of the experiments were carried out with varying duration. It was shown that after 46 days of lettuce cultivation dry edible biomass averaged 27, 2 g per plant. However accumulation of oxygen in the chamber, which required purging of the chamber, and decrease in the food value of the plants was observed. Reducing the duration of the tests allowed uninterrupted test without opening the system and also allowed estimation of the crop's carbon balance. Results of productivity, tissue composition, nutrient uptake and canopy photosynthesis of lettuce regardless of test duration are discussed in the paper.

Does sexual self-concept ambiguity moderate relations among perceived peer norms for alcohol use, alcohol-dependence symptomatology, and HIV risk-taking behavior?

PubMed

Talley, Amelia E; Brown, Jennifer L; Stevens, Angela K; Littlefield, Andrew K

2014-11-01

The current study examines the relation between peer descriptive norms for alcohol involvement and alcohol-dependence symptomatology and whether this relation differs as a function of sexual self-concept ambiguity (SSA). This study also examines the associations among peer descriptive norms for alcohol involvement, alcohol-dependence symptomatology, and lifetime HIV risk-taking behavior and how these relations are influenced by SSA. Women between ages 18 and 30 years (N = 351; M = 20.96, SD = 2.92) completed an online survey assessing sexual self-concept, peer descriptive norms, alcohol-dependence symptomatology, and HIV risk-taking behaviors. Structural equation modeling was used to test hypotheses of interest. There was a significant latent variable interaction between SSA and descriptive norms for peer alcohol use. There was a stronger positive relationship between peer descriptive norms for alcohol and alcohol-dependence symptomatology when SSA was higher compared with when SSA was lower. Both latent variables exhibited positive simple associations with alcohol-dependence symptoms. Peer descriptive norms for alcohol involvement directly and indirectly influenced HIV risk-taking behaviors, and the indirect influence was conditional based on SSA. The current findings illustrate complex, nuanced associations between perceived norms, identity-related self-concepts, and risky health behaviors from various domains. Future intervention efforts may be warranted to address both problem alcohol use and HIV-risk engagement among individuals with greater sexual self-concept ambiguity.

BMDS/SSA Integrated Sensing Demonstration (BISD)

NASA Astrophysics Data System (ADS)

Turner, T.; Springford, K.; Grimaldi, L.

2011-09-01

This demonstration is intended to provide a near-term prototype, leave-behind capability for integrating Ballistic Missile Defense System (BMDS) ground sensors for use in the Space Situational Awareness (SSA) mission. Closed-loop tasking and cueing capability will be implemented, and a demonstration of net-centric space data dissemination using the BMDS sensors will be undertaken using various SSA mission threads. The demonstration is designed to highlight the implications of modifying software and/or hardware at the BMDS command and control node so that cost, risk, and schedule for an operational implementation can be fully understood. Additionally, this demonstration is intended to assess the impacts to both mission areas as a multi-mission, non-traditional sensor capability is integrated into the SSA mission. A successful demonstration will have many leave-behind capabilities and first-of-its-kind achievements to include: a) an extensible SSA operational prototype configuration for BMDS X-Band radars such as AN/TPY-2 and Sea-Based X-Band (SBX) b) a prototype SSA tasking and cueing capability between the Joint Functional Component Command for Space (JFCC Space) Joint Space Operations Center (JSpOC) and the Command, Control, Battle Management, and Communications (C2BMC) Experimental Laboratory (X-Lab), extensible to the Combatant Commands (COCOMS), and out to BMDS sensors c) a capability for a twoway, net-centric, interface for JSpOC space operations, to include translation from net-centric communications to legacy systems and d) processing of BMDS X-Band Radar tracks in the Space Defense Operations Center (SPADOC).

Comparisons of Spectral Aerosol Single Scattering Albedo in Seoul, South Korea

NASA Technical Reports Server (NTRS)

Mok, Jungbin; Krotkov, Nickolay A.; Torres, Omar; Jethva, Hiren; Loughman, Robert P.; Spinei, Elena; Campanelli, Monica; Li, Zhanqing; Go, Sujung; Labow, Gordon;

Synthesis, structural, solubility and anticancer activity studies of salts using nucleobases and sulfonic acids coformer

NASA Astrophysics Data System (ADS)

Singh, Neetu; Singh, Udai P.; Nikhil, Kumar; Roy, Partha; Singh, Hariji

2017-10-01

The reactions of natural and unnatural nucleobases (cytosine (Cyt), adenine (Ade), 5-aminouracil (AU) and caffeine (Caff)) with sulfonic acids coformer (1,5-naphthalenedisulfonic acid, NDSA; 5-sulfosalicylic acid, SSA) resulted in the formation of salts viz. [NDSA.Cyt] (1), [NDSA.Ade] (2), [NDSA.AU] (3), [NDSA.Caff] (4), [SSA.Cyt] (5), [SSA.Ade] (6), [SSA.AU] (7), and [SSA.Caff] (8). The structural analysis revealed that salts 1, 4, 6 and 7 have intermolecular interactions between adjacent nucleobases which form two different homodimer shown in R22 (8) motif and assembled via complementary Nsbnd H⋯O and Nsbnd H⋯N interactions. However, in all other salts an intermediate supramolecular synthon pattern was observed between nucleobases and sulfonic acids. The lattice energy was also calculated by DFT to investigate whether salts were thermodynamically more stable than its coformer. The same was further confirmed by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis. The anticancer activity study of individual nucleobases and their NDSA salts were also performed on human breast (MCF-7) and lung (A 549) cancer cell. The salts formation of nucleobases with sulfonic acids improved their solubility, thereby demonstrating up to 8-fold increase in solubility of nucleobases.

Porous boron doped diamonds as metal-free catalysts for the oxygen reduction reaction in alkaline solution

NASA Astrophysics Data System (ADS)

Suo, Ni; Huang, Hao; Wu, Aimin; Cao, Guozhong; Hou, Xiaoduo; Zhang, Guifeng

2018-05-01

Porous boron doped diamonds (BDDs) were obtained on foam nickel substrates with a porosity of 80%, 85%, 90% and 95% respectively by hot filament chemical vapor deposition (HFCVD) technology. Scanning electron microscopy (SEM) reveals that uniform and compact BDDs with a cauliflower-like morphology have covered the overall frame of the foam nickel substrates. Raman spectroscopy shows that the BDDs have a poor crystallinity due to heavily doping boron. X-ray photoelectron spectroscopy (XPS) analysis effectively demonstrates that boron atoms can be successfully incorporated into the crystal lattice of diamonds. Electrochemical measurements indicate that the oxygen reduction potential is unaffected by the specific surface area (SSA), and both the onset potential and the limiting diffusion current density are enhanced with increasing SSA. It is also found that the durability and methanol tolerance of the boron doped diamond catalysts are attenuated as the increasing of SSA. The SSA of the catalyst is directly proportional to the oxygen reduction activity and inversely to the durability and methanol resistance. These results provide a reference to the application of porous boron doped diamonds as potential cathodic catalysts for the oxygen reduction reaction in alkaline solution by adjusting the SSA.

The mapping of the human 52-kD Ro/SSA autoantigen gene to human chromosome II, and its polymorphisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank, M.B.; Itoh, Kazuko; Fujisaku, Atsushi

1993-01-01

Autoantibodies to the ribonucleoprotein Ro/SSA occur in nearly half of the patients with systemic lupus erythematosus and are associated with lymphopenia, photosensitive dermatitis, and pulmonary and renal disease, which suggests that they have an immunopathologic role. The majority of Ro/SSA precipitin-positive patients produce serum antibodies that bind to the 60-kD and 52-kD Ro/SSA proteins. The authors previously isolated and determined the nucleotide sequence of a cDNA clone that encodes the 52-kD form of the human Ro/SSA protein. In the present study, they have determined the chromosomal location of the gene by in situ hybridization to the end of the shortmore » arm of chromosome 11. Hybridization of portions of the cDNA probe to restriction enzyme-digested DNA indicated the gene is composed of at least three exons. The exon encoding the putative zinc fingers of this protein was found to be distinct from that which encodes the leucine zipper. An RFLP of this gene was identified and is associated with the presence of lupus, primarily in black Americans. 60 refs., 3 figs., 3 tabs.« less

Real-time specific surface area measurements via laser-induced breakdown spectroscopy

USGS Publications Warehouse

Washburn, Kathryn E.; Birdwell, Justin E.; Howard, James E.

2017-01-01

From healthcare to cosmetics to environmental science, the specific surface area (SSA) of micro- and mesoporous materials or products can greatly affect their chemical and physical properties. SSA results are also widely used to examine source rocks in conventional and unconventional petroleum resource plays. Despite its importance, current methods to measure SSA are often cumbersome, time-consuming, or require cryogenic consumables (e.g., liquid nitrogen). These methods are not amenable to high-throughput environments, have stringent sample preparation requirements, and are not practical for use in the field. We present a new application of laser-induced breakdown spectroscopy for rapid measurement of SSA. This study evaluates geological samples, specifically organic-rich oil shales, but the approach is expected to be applicable to many other types of materials. The method uses optical emission spectroscopy to examine laser-generated plasma and quantify the amount of argon adsorbed to a sample during an inert gas purge. The technique can accommodate a wide range of sample sizes and geometries and has the potential for field use. These advantages for SSA measurement combined with the simultaneous acquisition of composition information make this a promising new approach for characterizing geologic samples and other materials.

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North Atlantic Aerosol Single Scattering Albedos: TARFOX and ACE-2 Results and Their Relation to Radiative Effects Derived from Satellite Optical Depths

NASA Technical Reports Server (NTRS)

Russell, P. B.; Bergstrom, R. W.; Schmid, B.; Livingston, J. M.; Redemann, J.; Quinn, P. K.; Carrico, C. M.; Rood, M. J.

2000-01-01

Bergstrom and Russell estimated direct solar radiative flux changes caused by atmospheric aerosols over the mid-latitude North Atlantic Ocean under cloud-free and cloudy conditions. They excluded African dust aerosols, primarily by restricting calculations to latitudes 25-60 N. As inputs they used midvisible aerosol optical depth (AOD) maps derived from AVHRR satellite measurements and aerosol intensive properties determined primarily in the 1996 IGAC Troposheric Aerosol Radiative Forcing Observational Experiment (TARFOX). Those aerosol intensive properties, which included optical depth wavelength dependence and spectra of single scattering albedo (SSA) and scattering asymmetry parameter, were also checked against initial properties from the 1997 North Atlantic Aerosol Characterization Experiment (ACE 2). Bergstrom and Russell investigated the sensitivity of their derived flux changes to assumed input parameters, including midvisible AOD, SSA, and scattering asymmetry parameter. Although the sensitivity of net flux change at the tropopause to SSA was moderate over the ocean (e.g., a SSA uncertainty of 0.07 produced a flux-change uncertainty of 21%), the sensitivity over common land surfaces can be much larger. Also, flux changes within and below the aerosol layer, which affect atmospheric stability, heating rates, and cloud formation and persistence, are quite sensitive to aerosol SSA. Therefore, this paper focuses on the question: "What have we learned from TARFOX and ACE 2 regarding aerosol single scattering albedo?" Three techniques were used in TARFOX to determine midvisible SSA. One of these derived SSA as a best-fit parameter in comparing radiative flux changes measured by airborne pyranometer to those computed from aerosol properties. Another technique combined airborne measurements of aerosol scattering and absorption by nephelometer and absorption photometer. A third technique obtained SSA from best-fit complex refractive indices derived by comparing vertical profiles of lidar backscatter, sunphotometer extinction, and relative size distribution. In ACE 2 midvisible SSA was determined both as a best-fit parameter in comparing measured and calculated flux changes at the surface and by combining nephelometer and absorption photometer measurements. The nephelometer/absorption-photometer results were obtained on the ACE 2 ship (10 m asl), at the Sagres, Portugal site at 50 m asl, and also on the Pelican aircraft. This paper presents and compares the TARFOX and ACE 2 SSA results from the above techniques for different situations (e.g., marine vs continental flows, "clean" vs polluted conditions). It also discusses the strengths and limitations of the techniques, including whether they describe the aerosol in its ambient state or as perturbed by sampling processes; whether they describe the aerosol at the surface, as a function of altitude, or integrated over a column; the ease of acquiring representative data sets; results obtained in tests of consistency with radiative flux changes, and the likelihood of various artifacts and errors.

Single-cell antibody nanowells: a novel technology in detecting anti-SSA/Ro60- and anti-SSB/La autoantibody-producing cells in peripheral blood of rheumatic disease patients.

PubMed

Esfandiary, Lida; Gupta, Nirupama; Voigt, Alexandria; Wanchoo, Arun; Chan, Edward K L; Sukumaran, Sukesh; Nguyen, Cuong Q

2016-05-17

Anti-SSA/Ro60 and anti-SSB/La are essential serological biomarkers for rheumatic diseases, specifically Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE). Currently, laboratory detection technology and platforms are designed with an emphasis on high-throughput methodology; therefore, the relationship of sensitivity with specificity remains a significant area for improvement. In this study, we used single-cell antibody nanowells (SCAN) technology to directly profile individual B cells producing antibodies against specific autoantigens such as SSA/Ro60 and SSB/La. Peripheral blood mononuclear cells were isolated using Ficoll gradient. Fluorescently labeled cells were added to fabricated nanowells and imaged using a high-speed epifluorescence microscope. The microengraving process was conducted using printed slides coated with immunoglobulins. Printed slides were hybridized with fluorescence-conjugated immunoglobulin G (IgG), SSA/Ro60, and SSB/La antigens. Microarray spots were analyzed for nanowells with single live B cells that produced antigen-specific autoantibodies. Our results indicate that SCAN can simultaneously detect high frequencies of anti-SSA/Ro60 and anti-SSB/La with a specific IgG isotype in peripheral blood mononuclear cells of patients, as well as measure their individual secretion levels. The data showed that patients with SS and SLE exhibited higher frequency and greater concentration of anti-SSA/Ro60- and anti-SSB/La-producing B cells in the IgG isotype. Furthermore, individual B cells of patients produced higher levels of IgG-specific anti-SSA/Ro60 autoantibody, but not IgG-specific anti-SSB/La autoantibody, compared with healthy control subjects. These results support the application of SCAN as a robust multiparametric analytical bioassay that can directly measure secretion of autoantibody and accurately report antigen-specific, autoantibody-producing cells.

Sessile serrated adenoma (SSA) vs. traditional serrated adenoma (TSA).

PubMed

Torlakovic, Emina Emilia; Gomez, Jose D; Driman, David K; Parfitt, Jeremy R; Wang, Chang; Benerjee, Tama; Snover, Dale C

2008-01-01

The morphologic distinction between various serrated polyps of the colorectum may be challenging. The distinction between sessile serrated adenoma (SSA) and traditional serrated adenoma (TSA) may be difficult using currently available criteria mostly based on cytologic characteristics. We have evaluated 66 serrated polyps including 29 SSA, 18 TSA, and 19 hyperplastic polyps for overall shape of the polyps, architectural features of individual crypts, the presence of eosinophilic cytoplasm, size and distribution of the proliferation and maturation zones, as well as Ki-67 and CK20 expression. The extent of the expression of CK20 and Ki-67 could not distinguish between the 3 types of serrated polyps, but the distribution of their expression was very helpful and differences were statistically significant. The distribution of Ki-67+ cells was the single most helpful distinguishing feature of the serrated polyp type (P<0.0001, chi test). Hyperplastic polyps had regular, symmetric, and increased Ki-67 expression. SSA had irregular, asymmetric, and highly variable expression of Ki-67. TSA had low Ki-67 expression, which was limited to "ectopic crypts" and admixed tubular adenomalike areas. In serrated polyps, ectopic crypt formation (ECF) defined by the presence of ectopic crypts with their bases not seated adjacent to the muscularis mucosae was nearly exclusive to TSA and was found in all cases, while the presence of cytologic atypia and eosinophilia of the cytoplasm were characteristic, but not limited to TSA. No evidence of ECF, but nevertheless abnormal distribution of proliferation zone was characteristic of SSA, whereas HP had neither. The presence of the ECF defines TSA in a more rigorous fashion than previous diagnostic criteria and also explains the biologic basis of exuberant protuberant growth associated with TSA and the lack of such growth in SSA. Recognition of this phenomenon may also help in exploring the genetic and molecular basis for differences between SSA and TSA, because these architectural abnormalities may well be a reflection of abnormalities in genetically programmed mucosal development.

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Environment-Level Strategies to Support Independent Control of Finances: A Response to the SSA Review of Financial Capability Determination Review.

PubMed

Harper, Annie; Rowe, Michael

2017-01-01

The Social Security Administration (SSA) recently completed an evaluation of the process by which representative payees are assigned. The SSA report is welcome, particularly for its focus on developing more accurate, real-world assessments of a person's financial capability and its recognition of the need for more flexible options for people with disabilities. Crucially, the report discusses the impact of the broader environment-specifically, conditions related to living in poverty. However, it provides no guidance about environmental interventions that could enable more beneficiaries to manage their funds without a payee. Innovative financial products could be offered to beneficiaries, and the retail industry could develop processes to support responsible financial management by people with mental illness. Changes to SSA benefits systems, including raising benefits levels and asset limits, could enable more beneficiaries to manage their funds independently.

Poverty and development: pulling forces and the challenges for nursing in Africa.

PubMed

Klopper, Hester C

2007-12-01

In September 2000 the United Nations Millennium Declaration was adopted and endorsed by 189 countries, translating into eight Millennium Development Goals (MDGs) to be reached by 2015. At the midpoint between the MDG adoption in 2000 and the 2015 target date for achieving the goals, Sub-Saharan Africa (SSA) is not on track to achieve their MDGs. Poverty and development are pulling forces and impact on the ability to achieve the MDGs in SSA, thus the main purpose of this article is to participate in the debate concerning the global theme of poverty and development and the challenges for the nursing profession. In this article the concepts of poverty and development are explored, and the existing trends with specific reference to SSA are investigated. An evaluation of the present status of SSA in reaching the MDG's is examined and the article concludes with a discussion of the challenges for nursing in Africa.

The African Genome Variation Project shapes medical genetics in Africa

PubMed Central

Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

2014-01-01

Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterisation of African genetic diversity is needed. The African Genome Variation Project (AGVP) provides a resource to help design, implement and interpret genomic studies in sub-Saharan Africa (SSA) and worldwide. The AGVP represents dense genotypes from 1,481 and whole genome sequences (WGS) from 320 individuals across SSA. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across SSA. We identify new loci under selection, including for malaria and hypertension. We show that modern imputation panels can identify association signals at highly differentiated loci across populations in SSA. Using WGS, we show further improvement in imputation accuracy supporting efforts for large-scale sequencing of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa, showing for the first time that such designs are feasible. PMID:25470054

Social Security and Disability Due to Mental Impairment in Adults.

PubMed

Goldman, Howard H; Frey, William D; Riley, Jarnee K

2018-05-07

The Social Security Administration (SSA) oversees two disability programs, Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI). Adults with mental impairments represent a very large component of the programs. Policy makers and SSA are concerned about the accuracy of disability determination and also about low levels of labor force participation among individuals with disabilities. Adults with mental impairments are challenging to assess for work-related functional limitations. They are also a challenge to return to labor force participation. SSA has sponsored several demonstration research programs focusing on improving the accuracy of disability determination and on interventions in supported employment to return individuals with mental impairments to competitive employment. This article reviews the demonstration research focused on both entry into the disability system (at the "front door") and potential exit from it (through the "back door"). All of the research holds promise to "right-size" the SSA disability program.

The incorrect usage of singular spectral analysis and discrete wavelet transform in hybrid models to predict hydrological time series

NASA Astrophysics Data System (ADS)

Du, Kongchang; Zhao, Ying; Lei, Jiaqiang

2017-09-01

In hydrological time series prediction, singular spectrum analysis (SSA) and discrete wavelet transform (DWT) are widely used as preprocessing techniques for artificial neural network (ANN) and support vector machine (SVM) predictors. These hybrid or ensemble models seem to largely reduce the prediction error. In current literature researchers apply these techniques to the whole observed time series and then obtain a set of reconstructed or decomposed time series as inputs to ANN or SVM. However, through two comparative experiments and mathematical deduction we found the usage of SSA and DWT in building hybrid models is incorrect. Since SSA and DWT adopt 'future' values to perform the calculation, the series generated by SSA reconstruction or DWT decomposition contain information of 'future' values. These hybrid models caused incorrect 'high' prediction performance and may cause large errors in practice.

Exploiting salient semantic analysis for information retrieval

NASA Astrophysics Data System (ADS)

Luo, Jing; Meng, Bo; Quan, Changqin; Tu, Xinhui

2016-11-01

Recently, many Wikipedia-based methods have been proposed to improve the performance of different natural language processing (NLP) tasks, such as semantic relatedness computation, text classification and information retrieval. Among these methods, salient semantic analysis (SSA) has been proven to be an effective way to generate conceptual representation for words or documents. However, its feasibility and effectiveness in information retrieval is mostly unknown. In this paper, we study how to efficiently use SSA to improve the information retrieval performance, and propose a SSA-based retrieval method under the language model framework. First, SSA model is adopted to build conceptual representations for documents and queries. Then, these conceptual representations and the bag-of-words (BOW) representations can be used in combination to estimate the language models of queries and documents. The proposed method is evaluated on several standard text retrieval conference (TREC) collections. Experiment results on standard TREC collections show the proposed models consistently outperform the existing Wikipedia-based retrieval methods.

ssaD1, a suppressor of secA51(Ts) that renders growth of Escherichia coli cold sensitive, is an early amber mutation in the transcription factor gene nusB.

PubMed Central

Rajapandi, T.; Oliver, D.

1994-01-01

Complementation analysis of the ssaD1 mutation, isolated as a suppressor of the secA51(Ts) mutation that renders growth of Escherichia coli cold sensitive, was used to show that ssaD corresponds to nusB, a gene known to be important in transcription antitermination. DNA sequence analysis of the ssaD1 allele showed that it creates an amber mutation in the 15th codon of nusB. Analysis of the effect of different levels of NusB protein on secA transcription and translation suggested that NusB plays little or no role in the control of secA expression. Accordingly, mechanisms by which nusB inactivation can lead to suppression of secA51(Ts) and secY24(Ts) mutations without affecting secA expression need to be considered. PMID:8021230

The sustainability solutions agenda.

PubMed

Sarewitz, Daniel; Clapp, Richard; Crumbley, Cathy; Kriebel, David; Tickner, Joel

2012-01-01

Progress toward a more sustainable society is usually described in a "knowledge-first" framework, where science characterizes a problem in terms of its causes and mechanisms as a basis for subsequent action. Here we present a different approach-A Sustainability Solutions Agenda (SSA)-which seeks from the outset to identify the possible pathways to solutions. SSA focuses on uncovering paths to sustainability by improving current technological practice, and applying existing knowledge to identify and evaluate technological alternatives. SSA allows people and organizations to transition toward greater sustainability without sacrificing essential technological functions, and therefore does not threaten the interests that depend on those functions. Whereas knowledge-first approaches view scientific information as sufficient to convince people to take the right actions, even if those actions are perceived as against their immediate interests, SSA allows values to evolve toward greater attention to sustainability as a result of the positive experience of solving a problem.

SpaceView (Viral Space Situational Awareness) One Year Update

NASA Astrophysics Data System (ADS)

Gleckler, A.; Butterfield, M.; Copenhaver, R.; Wade, A.; Apponi, A.

2013-09-01

Viral SSA takes advantage of the amateur astronomy community to provide an extremely low-cost and geographically-diverse network of optical SSA sites. In the spirit of programs such as DARPA's Grand Challenge and the National Weather Service's program of providing amateur meteorologists with weather stations linked to a central professional meteorological facility, we form a cooperative bond with a willing community of technicallyminded individuals. We term this program "viral" because we will qualify an initial set of astronomers for SSA operation and then use word of mouth in the astronomy community, as well as an outreach program, to pull in new observers. The use of modern remote controlled telescopes allows the incorporation of certified amateur, university, and commercial telescope systems. The availability of the local Viral SSA member for troubleshooting eliminates most significant costs of operating a large network. In this talk, we discuss the project's first year and the roadmap for the next two years.

Development of a Dependency Theory Toolbox for Database Design.

DTIC Science & Technology

1987-12-01

published algorithms and theorems , and hand simulating these algorithms can be a tedious and error prone chore. Additionally, since the process of...to design and study relational databases exists in the form of published algorithms and theorems . However, hand simulating these algorithms can be a...published algorithms and theorems . Hand simulating these algorithms can be a tedious and error prone chore. Therefore, a toolbox of algorithms and

Accuracy evaluation of Fourier series analysis and singular spectrum analysis for predicting the volume of motorcycle sales in Indonesia

NASA Astrophysics Data System (ADS)

Sasmita, Yoga; Darmawan, Gumgum

2017-08-01

This research aims to evaluate the performance of forecasting by Fourier Series Analysis (FSA) and Singular Spectrum Analysis (SSA) which are more explorative and not requiring parametric assumption. Those methods are applied to predicting the volume of motorcycle sales in Indonesia from January 2005 to December 2016 (monthly). Both models are suitable for seasonal and trend component data. Technically, FSA defines time domain as the result of trend and seasonal component in different frequencies which is difficult to identify in the time domain analysis. With the hidden period is 2,918 ≈ 3 and significant model order is 3, FSA model is used to predict testing data. Meanwhile, SSA has two main processes, decomposition and reconstruction. SSA decomposes the time series data into different components. The reconstruction process starts with grouping the decomposition result based on similarity period of each component in trajectory matrix. With the optimum of window length (L = 53) and grouping effect (r = 4), SSA predicting testing data. Forecasting accuracy evaluation is done based on Mean Absolute Percentage Error (MAPE), Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). The result shows that in the next 12 month, SSA has MAPE = 13.54 percent, MAE = 61,168.43 and RMSE = 75,244.92 and FSA has MAPE = 28.19 percent, MAE = 119,718.43 and RMSE = 142,511.17. Therefore, to predict volume of motorcycle sales in the next period should use SSA method which has better performance based on its accuracy.

Deforestation risk due to commodity crop expansion in sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Ordway, Elsa M.; Asner, Gregory P.; Lambin, Eric F.

2017-04-01

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crops to sub-Saharan Africa (SSA). We assess the effects of domestic- and export-oriented agricultural expansion on deforestation in SSA in recent decades. Analyses were conducted at the global, regional and local scales. We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Côte d’Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ± 17.93) and lowest proportions of potentially available cropland outside forest areas (1% ± 0.89). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41 582 thousand ha. Cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1. However, cocoa only amounted to 0.89% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Land-use changes associated with large-scale investments remain to be observed in many countries. Although domestic demand for commodity crops was associated with most agricultural expansion, we provide evidence of a growing influence of distant markets on land-use change in SSA.