Using Soluble Reactive Phosphorus and Ammonia to Identify Point Source Discharge from Large Livestock Facilities

NASA Astrophysics Data System (ADS)

Borrello, M. C.; Scribner, M.; Chessin, K.

2013-12-01

A growing body of research draws attention to the negative environmental impacts on surface water from large livestock facilities. These impacts are mostly in the form of excessive nutrient loading resulting in significantly decreased oxygen levels. Over-application of animal waste on fields as well as direct discharge into surface water from facilities themselves has been identified as the main contributor to the development of hypoxic zones in Lake Erie, Chesapeake Bay and the Gulf of Mexico. Some regulators claim enforcement of water quality laws is problematic because of the nature and pervasiveness of non-point source impacts. Any direct discharge by a facility is a violation of permits governed by the Clean Water Act, unless the facility has special dispensation for discharge. Previous research by the principal author and others has shown runoff and underdrain transport are the main mechanisms by which nutrients enter surface water. This study utilized previous work to determine if the effects of non-point source discharge can be distinguished from direct (point-source) discharge using simple nutrient analysis and dissolved oxygen (DO) parameters. Nutrient and DO parameters were measured from three sites: 1. A stream adjacent to a field receiving manure, upstream of a large livestock facility with a history of direct discharge, 2. The same stream downstream of the facility and 3. A stream in an area relatively unimpacted by large-scale agriculture (control site). Results show that calculating a simple Pearson correlation coefficient (r) of soluble reactive phosphorus (SRP) and ammonia over time as well as temperature and DO, distinguishes non-point source from point source discharge into surface water. The r value for SRP and ammonia for the upstream site was 0.01 while the r value for the downstream site was 0.92. The control site had an r value of 0.20. Likewise, r values were calculated on temperature and DO for each site. High negative correlations

[A landscape ecological approach for urban non-point source pollution control].

PubMed

Guo, Qinghai; Ma, Keming; Zhao, Jingzhu; Yang, Liu; Yin, Chengqing

2005-05-01

Urban non-point source pollution is a new problem appeared with the speeding development of urbanization. The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution, and more difficult to control. Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution, mainly adopting local repairing practices to control the pollutants in surface runoff. Because of the close relationship between urban land use patterns and non-point source pollution, it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution, which needs, firstly, analyzing and evaluating the influence of landscape structure on water-bodies, pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields, and secondly, adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern, and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

Searches for point sources in the Galactic Center region

NASA Astrophysics Data System (ADS)

di Mauro, Mattia; Fermi-LAT Collaboration

2017-01-01

Several groups have demonstrated the existence of an excess in the gamma-ray emission around the Galactic Center (GC) with respect to the predictions from a variety of Galactic Interstellar Emission Models (GIEMs) and point source catalogs. The origin of this excess, peaked at a few GeV, is still under debate. A possible interpretation is that it comes from a population of unresolved Millisecond Pulsars (MSPs) in the Galactic bulge. We investigate the detection of point sources in the GC region using new tools which the Fermi-LAT Collaboration is developing in the context of searches for Dark Matter (DM) signals. These new tools perform very fast scans iteratively testing for additional point sources at each of the pixels of the region of interest. We show also how to discriminate between point sources and structural residuals from the GIEM. We apply these methods to the GC region considering different GIEMs and testing the DM and MSPs intepretations for the GC excess. Additionally, we create a list of promising MSP candidates that could represent the brightest sources of a MSP bulge population.

Impact of point-source pollution on phosphorus and nitrogen cycling in stream-bed sediments.

PubMed

Palmer-Felgate, Elizabeth J; Mortimer, Robert J G; Krom, Michael D; Jarvie, Helen P

2010-02-01

Diffusive equilibration in thin films was used to study the cycling of phosphorus and nitrogen at the sediment-water interface in situ and with minimal disturbance to redox conditions. Soluble reactive phosphate (SRP), nitrate, nitrite, ammonium, sulfate, iron, and manganese profiles were measured in a rural stream, 12 m upstream, adjacent to, and 8 m downstream of a septic tank discharge. Sewage fungus adjacent to the discharge resulted in anoxic conditions directly above the sediment. SRP and ammonium increased with depth through the fungus layer to environmentally significant concentrations (440 and 1800 microM, respectively) due to release at the sediment surface. This compared to only 0.8 microM of SRP and 2.0 microM of ammonium in the water column upstream of the discharge. Concomitant removal of ammonium, nitrite and nitrate within 0.5 cm below the fungus-water interface provided evidence for anaerobic ammonium oxidation (anammox). "Hotspots" of porewater SRP (up to 350 microM) at the downstream site demonstrated potential in-stream storage of the elevated P concentrations from the effluent. These results provide direct in situ evidence of phosphorus and nitrogen release from river-bed sediments under anoxic conditions created by sewage-fungus, and highlight the wider importance of redox conditions and rural point sources on in-stream nutrient cycling.

Very Luminous X-ray Point Sources in Starburst Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E.; Heckman, T.; Ptak, A.; Weaver, K. A.; Strickland, D.

Extranuclear X-ray point sources in external galaxies with luminosities above 1039.0 erg/s are quite common in elliptical, disk and dwarf galaxies, with an average of ~ 0.5 and dwarf galaxies, with an average of ~0.5 sources per galaxy. These objects may be a new class of object, perhaps accreting intermediate-mass black holes, or beamed stellar mass black hole binaries. Starburst galaxies tend to have a larger number of these intermediate-luminosity X-ray objects (IXOs), as well as a large number of lower-luminosity (1037 - 1039 erg/s) point sources. These point sources dominate the total hard X-ray emission in starburst galaxies. We present a review of both types of objects and discuss possible schemes for their formation.

X-ray Point Source Populations in Spiral and Elliptical Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E.; Heckman, T.; Weaver, K.; Ptak, A.; Strickland, D.

2001-12-01

In the years of the Einstein and ASCA satellites, it was known that the total hard X-ray luminosity from non-AGN galaxies was fairly well correlated with the total blue luminosity. However, the origin of this hard component was not well understood. Some possibilities that were considered included X-ray binaries, extended upscattered far-infrared light via the inverse-Compton process, extended hot 107 K gas (especially in ellipitical galaxies), or even an active nucleus. Now, for the first time, we know from Chandra images that a significant amount of the total hard X-ray emission comes from individual X-ray point sources. We present here spatial and spectral analyses of Chandra data for X-ray point sources in a sample of ~40 galaxies, including both spiral galaxies (starbursts and non-starbursts) and elliptical galaxies. We shall discuss the relationship between the X-ray point source population and the properties of the host galaxies. We show that the slopes of the point-source X-ray luminosity functions are different for different host galaxy types and discuss possible reasons why. We also present detailed X-ray spectral analyses of several of the most luminous X-ray point sources (i.e., IXOs, a.k.a. ULXs), and discuss various scenarios for the origin of the X-ray point sources.

Trophic coupling between two adjacent benthic food webs within a man-made intertidal area: A stable isotopes evidence

NASA Astrophysics Data System (ADS)

Schaal, Gauthier; Riera, Pascal; Leroux, Cédric

2008-04-01

This study aimed at establishing the effects of human-made physical modifications on the trophic structure and functioning of an intertidal benthic food web in Arcachon Bay (France). The main food sources and the most representative consumers were sampled on an artificial rocky dyke and its adjacent seagrass meadow. The food sources of consumers were inferred through the use of carbon and nitrogen stable isotopes. The contributions of the different food sources to the diets of the consumers were established using the Isosource mixing model. In order to reduce the range of feasible contributions, additional non-isotopic constraints were added when necessary to the outputs of this model. We observed a more complex food web than previously shown for artificial habitats. Moreover, it appears that several consumers inhabiting the artificial environment base most of their diet on allochtonous eelgrass-derived detritus. In turn, several consumers inhabiting the eelgrass meadow consumed significantly macroalgae-derived material originating from the adjacent artificial rocky area. These results point out that the food webs associated to adjacent habitats can influence each other through the utilisation of exported organic matter.

Tapered monocapillary-optics for point source applications

DOEpatents

Hirsch, Gregory

2000-01-01

A glass or metal wire is precisely etched to form the paraboloidal or ellipsoidal shape of the final desired capillary optic. This shape is created by carefully controlling the withdrawal speed of the wire from an etchant bath. In the case of a complete ellipsoidal capillary, the etching operation is performed twice in opposite directions on adjacent wire segments. The etched wire undergoes a subsequent operation to create an extremely smooth surface. This surface is coated with a layer of material which is selected to maximize the reflectivity of the radiation. This reflective surface may be a single layer for wideband reflectivity, or a multilayer coating for optimizing the reflectivity in a narrower wavelength interval. The coated wire is built up with a reinforcing layer, typically by a plating operation. The initial wire is removed by either an etching procedure or mechanical force. Prior to removing the wire, the capillary is typically bonded to a support substrate. One option for attaching the wire to the substrate produces a monolithic structure by essentially burying it under a layer of plating which covers both the wire and the substrate. The capillary optic is used for efficiently collecting and redirecting the divergent radiation from a source which could be the anode of an x-ray tube, a plasma source, the fluorescent radiation from an electron microprobe, or some other source of radiation.

X-ray Point Source Populations in Spiral and Elliptical Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E.; Heckman, T.; Weaver, K.; Strickland, D.

2002-01-01

The hard-X-ray luminosity of non-active galaxies has been known to be fairly well correlated with the total blue luminosity since the days of the Einstein satellite. However, the origin of this hard component was not well understood. Some possibilities that were considered included X-ray binaries, extended upscattered far-infrared light via the inverse-Compton process, extended hot 107 K gas (especially in ellipitical galaxies), or even an active nucleus. Chandra images of normal, elliptical and starburst galaxies now show that a significant amount of the total hard X-ray emission comes from individual point sources. We present here spatial and spectral analyses of the point sources in a small sample of Chandra obervations of starburst galaxies, and compare with Chandra point source analyses from comparison galaxies (elliptical, Seyfert and normal galaxies). We discuss possible relationships between the number and total hard luminosity of the X-ray point sources and various measures of the galaxy star formation rate, and discuss possible options for the numerous compact sources that are observed.

Interferometric superlocalization of two incoherent optical point sources.

PubMed

Nair, Ranjith; Tsang, Mankei

2016-02-22

A novel interferometric method - SLIVER (Super Localization by Image inVERsion interferometry) - is proposed for estimating the separation of two incoherent point sources with a mean squared error that does not deteriorate as the sources are brought closer. The essential component of the interferometer is an image inversion device that inverts the field in the transverse plane about the optical axis, assumed to pass through the centroid of the sources. The performance of the device is analyzed using the Cramér-Rao bound applied to the statistics of spatially-unresolved photon counting using photon number-resolving and on-off detectors. The analysis is supported by Monte-Carlo simulations of the maximum likelihood estimator for the source separation, demonstrating the superlocalization effect for separations well below that set by the Rayleigh criterion. Simulations indicating the robustness of SLIVER to mismatch between the optical axis and the centroid are also presented. The results are valid for any imaging system with a circularly symmetric point-spread function.

Analysis of point source size on measurement accuracy of lateral point-spread function of confocal Raman microscopy

NASA Astrophysics Data System (ADS)

Fu, Shihang; Zhang, Li; Hu, Yao; Ding, Xiang

2018-01-01

Confocal Raman Microscopy (CRM) has matured to become one of the most powerful instruments in analytical science because of its molecular sensitivity and high spatial resolution. Compared with conventional Raman Microscopy, CRM can perform three dimensions mapping of tiny samples and has the advantage of high spatial resolution thanking to the unique pinhole. With the wide application of the instrument, there is a growing requirement for the evaluation of the imaging performance of the system. Point-spread function (PSF) is an important approach to the evaluation of imaging capability of an optical instrument. Among a variety of measurement methods of PSF, the point source method has been widely used because it is easy to operate and the measurement results are approximate to the true PSF. In the point source method, the point source size has a significant impact on the final measurement accuracy. In this paper, the influence of the point source sizes on the measurement accuracy of PSF is analyzed and verified experimentally. A theoretical model of the lateral PSF for CRM is established and the effect of point source size on full-width at half maximum of lateral PSF is simulated. For long-term preservation and measurement convenience, PSF measurement phantom using polydimethylsiloxane resin, doped with different sizes of polystyrene microspheres is designed. The PSF of CRM with different sizes of microspheres are measured and the results are compared with the simulation results. The results provide a guide for measuring the PSF of the CRM.

Impacts of the Detection of Cassiopeia A Point Source.

PubMed

Umeda; Nomoto; Tsuruta; Mineshige

2000-05-10

Very recently the Chandra first light observation discovered a point-like source in the Cassiopeia A supernova remnant. This detection was subsequently confirmed by the analyses of the archival data from both ROSAT and Einstein observations. Here we compare the results from these observations with the scenarios involving both black holes (BHs) and neutron stars (NSs). If this point source is a BH, we offer as a promising model a disk-corona type model with a low accretion rate in which a soft photon source at approximately 0.1 keV is Comptonized by higher energy electrons in the corona. If it is an NS, the dominant radiation observed by Chandra most likely originates from smaller, hotter regions of the stellar surface, but we argue that it is still worthwhile to compare the cooler component from the rest of the surface with cooling theories. We emphasize that the detection of this point source itself should potentially provide enormous impacts on the theories of supernova explosion, progenitor scenario, compact remnant formation, accretion to compact objects, and NS thermal evolution.

STATISTICS OF GAMMA-RAY POINT SOURCES BELOW THE FERMI DETECTION LIMIT

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

Malyshev, Dmitry; Hogg, David W., E-mail: dm137@nyu.edu

2011-09-10

An analytic relation between the statistics of photons in pixels and the number counts of multi-photon point sources is used to constrain the distribution of gamma-ray point sources below the Fermi detection limit at energies above 1 GeV and at latitudes below and above 30 deg. The derived source-count distribution is consistent with the distribution found by the Fermi Collaboration based on the first Fermi point-source catalog. In particular, we find that the contribution of resolved and unresolved active galactic nuclei (AGNs) to the total gamma-ray flux is below 20%-25%. In the best-fit model, the AGN-like point-source fraction is 17%more » {+-} 2%. Using the fact that the Galactic emission varies across the sky while the extragalactic diffuse emission is isotropic, we put a lower limit of 51% on Galactic diffuse emission and an upper limit of 32% on the contribution from extragalactic weak sources, such as star-forming galaxies. Possible systematic uncertainties are discussed.« less

Variability of adjacency effects in sky reflectance measurements.

PubMed

Groetsch, Philipp M M; Gege, Peter; Simis, Stefan G H; Eleveld, Marieke A; Peters, Steef W M

2017-09-01

Sky reflectance R sky (λ) is used to correct in situ reflectance measurements in the remote detection of water color. We analyzed the directional and spectral variability in R sky (λ) due to adjacency effects against an atmospheric radiance model. The analysis is based on one year of semi-continuous R sky (λ) observations that were recorded in two azimuth directions. Adjacency effects contributed to R sky (λ) dependence on season and viewing angle and predominantly in the near-infrared (NIR). For our test area, adjacency effects spectrally resembled a generic vegetation spectrum. The adjacency effect was weakly dependent on the magnitude of Rayleigh- and aerosol-scattered radiance. The reflectance differed between viewing directions 5.4±6.3% for adjacency effects and 21.0±19.8% for Rayleigh- and aerosol-scattered R sky (λ) in the NIR. Under which conditions in situ water reflectance observations require dedicated correction for adjacency effects is discussed. We provide an open source implementation of our method to aid identification of such conditions.

Do Mangroves Subsidize Carbon to Adjacent Mudflat Fish Communities?

NASA Astrophysics Data System (ADS)

Henkel, S.; Kasten, S.; Hartmann, J.; Staubwasser, M.; Hernandez, M. F.; West, L.; Midway, S. R.; Polito, M. J.

2017-12-01

Mangroves are often implicated as energetic sources for fisheries productivity. However, the validity of this connection still remains in contention. Stable isotopes may provide answers by tracking the use of specific basal carbon sources in fish and invertebrates living in mangrove-mudflat habitat mosaics. We analyzed 307 consumer samples representing n=44 fish and invertebrate species collected from mangrove forest creeks and adjacent mudflats in coastal Tanzania using bulk carbon and nitrogen stable isotope analysis. Given the proposed high productivity of mangrove habitats, we hypothesize that mudflat communities will have carbon stable isotope values similar to mangrove communities either through the flux of mangrove carbon into adjacent mudflats and/or via the movement of mudflat fish communities into and out of mangrove habitats. Alternatively, mangrove carbon is often refractory, which may result in mudflat communities with isotopic values that differ from those found in adjacent mangrove communities. This scenario would suggest limited carbon flow between mudflat and mangrove food webs and that the movement of fish into and out of mangrove habitats is related to shelter from predation more than feeding. Data analysis is ongoing to test these competing hypotheses. By understanding the contribution of mangrove carbon to adjacent habitats, managers in Tanzania can make better informed decisions regarding the protection of mangroves and the local fisheries, which are a crucial source of income and food.

HerMES: point source catalogues from Herschel-SPIRE observations II

NASA Astrophysics Data System (ADS)

Wang, L.; Viero, M.; Clarke, C.; Bock, J.; Buat, V.; Conley, A.; Farrah, D.; Guo, K.; Heinis, S.; Magdis, G.; Marchetti, L.; Marsden, G.; Norberg, P.; Oliver, S. J.; Page, M. J.; Roehlly, Y.; Roseboom, I. G.; Schulz, B.; Smith, A. J.; Vaccari, M.; Zemcov, M.

2014-11-01

The Herschel Multi-tiered Extragalactic Survey (HerMES) is the largest Guaranteed Time Key Programme on the Herschel Space Observatory. With a wedding cake survey strategy, it consists of nested fields with varying depth and area totalling ˜380 deg2. In this paper, we present deep point source catalogues extracted from Herschel-Spectral and Photometric Imaging Receiver (SPIRE) observations of all HerMES fields, except for the later addition of the 270 deg2 HerMES Large-Mode Survey (HeLMS) field. These catalogues constitute the second Data Release (DR2) made in 2013 October. A sub-set of these catalogues, which consists of bright sources extracted from Herschel-SPIRE observations completed by 2010 May 1 (covering ˜74 deg2) were released earlier in the first extensive data release in 2012 March. Two different methods are used to generate the point source catalogues, the SUSSEXTRACTOR point source extractor used in two earlier data releases (EDR and EDR2) and a new source detection and photometry method. The latter combines an iterative source detection algorithm, STARFINDER, and a De-blended SPIRE Photometry algorithm. We use end-to-end Herschel-SPIRE simulations with realistic number counts and clustering properties to characterize basic properties of the point source catalogues, such as the completeness, reliability, photometric and positional accuracy. Over 500 000 catalogue entries in HerMES fields (except HeLMS) are released to the public through the HeDAM (Herschel Database in Marseille) website (http://hedam.lam.fr/HerMES).

A method to analyze "source-sink" structure of non-point source pollution based on remote sensing technology.

PubMed

Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui

2013-11-01

With the purpose of providing scientific basis for environmental planning about non-point source pollution prevention and control, and improving the pollution regulating efficiency, this paper established the Grid Landscape Contrast Index based on Location-weighted Landscape Contrast Index according to the "source-sink" theory. The spatial distribution of non-point source pollution caused by Jiulongjiang Estuary could be worked out by utilizing high resolution remote sensing images. The results showed that, the area of "source" of nitrogen and phosphorus in Jiulongjiang Estuary was 534.42 km(2) in 2008, and the "sink" was 172.06 km(2). The "source" of non-point source pollution was distributed mainly over Xiamen island, most of Haicang, east of Jiaomei and river bank of Gangwei and Shima; and the "sink" was distributed over southwest of Xiamen island and west of Shima. Generally speaking, the intensity of "source" gets weaker along with the distance from the seas boundary increase, while "sink" gets stronger. Copyright © 2013 Elsevier Ltd. All rights reserved.

Point and Condensed Hα Sources in the Interior of M33

NASA Astrophysics Data System (ADS)

Moody, J. Ward; Hintz, Eric G.; Roming, Peter; Joner, Michael D.; Bucklein, Brian

2017-01-01

A variety of interesting objects such as Wolf-Rayet stars, tight OB associations, planetary nebula, x-ray binaries, etc. can be discovered as point or condensed sources in Hα surveys. How these objects distribute through a galaxy sheds light on the galaxy star formation rate and history, mass distribution, and dynamics. The nearby galaxy M33 is an excellent place to study the distribution of Hα-bright point sources in a flocculant spiral galaxy. We have reprocessed an archived WIYN continuum-subtracted Hα image of the inner 6.5' of the nearby galaxy M33 and, employing both eye and machine searches, have tabulated sources with a flux greater than 1 x 10-15 erg cm-2sec-1. We have identified 152 unresolved point sources and 122 marginally resolved condensed sources, 38 of which have not been previously cataloged. We present a map of these sources and discuss their probable identifications.

Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web.

PubMed

Kwon, Sae Yun; Blum, Joel D; Nadelhoffer, Knute J; Timothy Dvonch, J; Tsui, Martin Tsz-Ki

2015-11-01

Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ(202)Hg and Δ(199)Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ(202)Hg and Δ(199)Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ(199)Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ(202)Hg and Δ(199)Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ(199)Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ(199)Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

Analysis of non-point and point source pollution in China: case study in Shima Watershed in Guangdong Province

NASA Astrophysics Data System (ADS)

Fang, Huaiyang; Lu, Qingshui; Gao, Zhiqiang; Shi, Runhe; Gao, Wei

2013-09-01

China economy has been rapidly increased since 1978. Rapid economic growth led to fast growth of fertilizer and pesticide consumption. A significant portion of fertilizers and pesticides entered the water and caused water quality degradation. At the same time, rapid economic growth also caused more and more point source pollution discharge into the water. Eutrophication has become a major threat to the water bodies. Worsening environment problems forced governments to take measures to control water pollution. We extracted land cover from Landsat TM images; calculated point source pollution with export coefficient method; then SWAT model was run to simulate non-point source pollution. We found that the annual TP loads from industry pollution into rivers are 115.0 t in the entire watershed. Average annual TP loads from each sub-basin ranged from 0 to 189.4 ton. Higher TP loads of each basin from livestock and human living mainly occurs in the areas where they are far from large towns or cities and the TP loads from industry are relatively low. Mean annual TP loads that delivered to the streams was 246.4 tons and the highest TP loads occurred in north part of this area, and the lowest TP loads is mainly distributed in middle part. Therefore, point source pollution has much high proportion in this area and governments should take measures to control point source pollution.

Probing dim point sources in the inner Milky Way using PCAT

NASA Astrophysics Data System (ADS)

Daylan, Tansu; Portillo, Stephen K. N.; Finkbeiner, Douglas P.

2017-01-01

Poisson regression of the Fermi-LAT data in the inner Milky Way reveals an extended gamma-ray excess. An important question is whether the signal is coming from a collection of unresolved point sources, possibly old recycled pulsars, or constitutes a truly diffuse emission component. Previous analyses have relied on non-Poissonian template fits or wavelet decomposition of the Fermi-LAT data, which find evidence for a population of dim point sources just below the 3FGL flux limit. In order to be able to draw conclusions about the flux distribution of point sources at the dim end, we employ a Bayesian trans-dimensional MCMC framework by taking samples from the space of catalogs consistent with the observed gamma-ray emission in the inner Milky Way. The software implementation, PCAT (Probabilistic Cataloger), is designed to efficiently explore that catalog space in the crowded field limit such as in the galactic plane, where the model PSF, point source positions and fluxes are highly degenerate. We thus generate fair realizations of the underlying MSP population in the inner galaxy and constrain the population characteristics such as the radial and flux distribution of such sources.

BEAMLINE-CONTROLLED STEERING OF SOURCE-POINT ANGLE AT THE ADVANCED PHOTON SOURCE

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

Emery, L.; Fystro, G.; Shang, H.

An EPICS-based steering software system has been implemented for beamline personnel to directly steer the angle of the synchrotron radiation sources at the Advanced Photon Source. A script running on a workstation monitors "start steering" beamline EPICS records, and effects a steering given by the value of the "angle request" EPICS record. The new system makes the steering process much faster than before, although the older steering protocols can still be used. The robustness features of the original steering remain. Feedback messages are provided to the beamlines and the accelerator operators. Underpinning this new steering protocol is the recent refinementmore » of the global orbit feedback process whereby feedforward of dipole corrector set points and orbit set points are used to create a local steering bump in a rapid and seamless way.« less

Study of Heavy Metals in a Wetland Area Adjacent to a Waste Disposal Site Near Resolute Bay, Canadian High Arctic

NASA Astrophysics Data System (ADS)

Lund, K. E.; Young, K. L.

2004-05-01

Heavy metal contamination in High Arctic systems is of growing concern. Studies have been conducted measuring long range and large point source pollutants, but little research has been done on small point sources such as municipal waste disposal sites. Many Arctic communities are coastal, and local people consume marine wildlife in which concentrations of heavy metals can accumulate. Waste disposal sites are often located in very close proximity to the coastline and leaching of these metals could contaminate food sources on a local scale. Cadmium and lead are the metals focussed on by this study, as the Northern Contaminants Program recognizes them as metals of concern. During the summer of 2003 a study was conducted near Resolute, Nunavut, Canada, to determine the extent of cadmium and lead leaching from a local dumpsite to an adjacent wetland. The ultimate fate of these contaminants is approximately 1 km downslope in the ocean. Transects covering an area of 0.3 km2 were established downslope from the point of disposal and water and soil samples were collected and analyzed for cadmium and lead. Only trace amounts of cadmium and lead were found in the water samples. In the soil samples, low uniform concentrations of cadmium were found that were slightly above background levels, except for adjacent to the point of waste input where higher concentrations were found. Lead soil concentrations were higher than cadmium and varied spatially with soil material and moisture. Overall, excessive amounts of cadmium and lead contamination do not appear to be entering the marine ecosystem. However, soil material and moisture should be considered when establishing waste disposal sites in the far north

Point and Compact Hα Sources in the Interior of M33

NASA Astrophysics Data System (ADS)

Moody, J. Ward; Hintz, Eric G.; Joner, Michael D.; Roming, Peter W. A.; Hintz, Maureen L.

2017-12-01

A variety of interesting objects such as Wolf-Rayet stars, tight OB associations, planetary nebulae, X-ray binaries, etc., can be discovered as point or compact sources in Hα surveys. How these objects distribute through a galaxy sheds light on the galaxy star formation rate and history, mass distribution, and dynamics. The nearby galaxy M33 is an excellent place to study the distribution of Hα-bright point sources in a flocculant spiral galaxy. We have reprocessed an archived WIYN continuum-subtracted Hα image of the inner 6.‧5 × 6.‧5 of M33 and, employing both eye and machine searches, have tabulated sources with a flux greater than approximately 10-15 erg cm-2s-1. We have effectively recovered previously mapped H II regions and have identified 152 unresolved point sources and 122 marginally resolved compact sources, of which 39 have not been previously identified in any archive. An additional 99 Hα sources were found to have sufficient archival flux values to generate a Spectral Energy Distribution. Using the SED, flux values, Hα flux value, and compactness, we classified 67 of these sources.

A NEW METHOD FOR FINDING POINT SOURCES IN HIGH-ENERGY NEUTRINO DATA

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

Fang, Ke; Miller, M. Coleman

The IceCube collaboration has reported the first detection of high-energy astrophysical neutrinos, including ∼50 high-energy starting events, but no individual sources have been identified. It is therefore important to develop the most sensitive and efficient possible algorithms to identify the point sources of these neutrinos. The most popular current method works by exploring a dense grid of possible directions to individual sources, and identifying the single direction with the maximum probability of having produced multiple detected neutrinos. This method has numerous strengths, but it is computationally intensive and because it focuses on the single best location for a point source,more » additional point sources are not included in the evidence. We propose a new maximum likelihood method that uses the angular separations between all pairs of neutrinos in the data. Unlike existing autocorrelation methods for this type of analysis, which also use angular separations between neutrino pairs, our method incorporates information about the point-spread function and can identify individual point sources. We find that if the angular resolution is a few degrees or better, then this approach reduces both false positive and false negative errors compared to the current method, and is also more computationally efficient up to, potentially, hundreds of thousands of detected neutrinos.« less

Multiwavelength counterparts of the point sources in the Chandra Source Catalog

NASA Astrophysics Data System (ADS)

Reynolds, Michael; Civano, Francesca Maria; Fabbiano, Giuseppina; D'Abrusco, Raffaele

2018-01-01

The most recent release of the Chandra Source Catalog (CSC) version 2.0 comprises more than $\\sim$350,000 point sources, down to fluxes of $\\sim$10$^{-16}$ erg/cm$^2$/s, covering $\\sim$500 deg$^2$ of the sky, making it one of the best available X-ray catalogs to date. There are many reasons to have multiwavelength counterparts for sources, one such reason is that X-ray information alone is not enough to identify the sources and divide them between galactic and extragalactic origin, therefore multiwavelength data associated to each X-ray source is crucial for classification and scientific analysis of the sample. To perform this multiwavelength association, we are going to employ the recently released versatile tool NWAY (Salvato et al. 2017), based on a Bayesian algorithm for cross-matching multiple catalogs. NWAY allows the combination of multiple catalogs at the same time, provides a probability for the matches, even in case of non-detection due to different depth of the matching catalogs, and it can be used by including priors on the nature of the sources (e.g. colors, magnitudes, etc). In this poster, we are presenting the preliminary analysis using the CSC sources above the galactic plane matched to the WISE All-Sky catalog, SDSS, Pan-STARRS and GALEX.

The Herschel-SPIRE Point Source Catalog Version 2

NASA Astrophysics Data System (ADS)

Schulz, Bernhard; Marton, Gábor; Valtchanov, Ivan; María Pérez García, Ana; Pintér, Sándor; Appleton, Phil; Kiss, Csaba; Lim, Tanya; Lu, Nanyao; Papageorgiou, Andreas; Pearson, Chris; Rector, John; Sánchez Portal, Miguel; Shupe, David; Tóth, Viktor L.; Van Dyk, Schuyler; Varga-Verebélyi, Erika; Xu, Kevin

2018-01-01

The Herschel-SPIRE instrument mapped about 8% of the sky in Submillimeter broad-band filters centered at 250, 350, and 500 microns (1199, 857, 600 GHz) with spatial resolutions of 17.9”, 24.2”, and 35.4” respectively. We present here the 2nd version of the SPIRE Point Source Catalog (SPSC). Stacking on WISE 22 micron catalog sources led to the identification of 108 maps, out of 6878, that had astrometry offsets of greater than 5”. After fixing these deviations and re-derivation of all affected map-mosaics, we repeated the systematic and homogeneous source extraction performed on all maps, using an improved version of the 4 different photometry extraction methods that were already employed in the generation of the first version catalog. Only regions affected by strong Galactic emission, mostly in the Galactic Plane, were excluded, as they exceeded the limits of the available source extraction methods. Aimed primarily at point sources, that allow for the best photometric accuracy, the catalog contains also significant fractions of slightly extended sources. With most SPIRE maps being confusion limited, uncertainties in flux densities were established as a function of structure noise and flux density, based on the results of artificial source insertion experiments into real data along a range of celestial backgrounds. Many sources have been rejected that do not pass the imposed SNR threshold, especially at flux densities approaching the extragalactic confusion limit. A range of additional flags provide information on the reliability of the flux information, as well as the spatial extent and orientation of a source. The catalog should be particularly helpful for determining cold dust content in extragalactic and galactic sources with low to moderate background confusion. We present an overview of catalog construction, detailed content, and validation results, with focus on the improvements achieved in the second version that is soon to be released.

Open-Source Automated Mapping Four-Point Probe.

PubMed

Chandra, Handy; Allen, Spencer W; Oberloier, Shane W; Bihari, Nupur; Gwamuri, Jephias; Pearce, Joshua M

2017-01-26

Scientists have begun using self-replicating rapid prototyper (RepRap) 3-D printers to manufacture open source digital designs of scientific equipment. This approach is refined here to develop a novel instrument capable of performing automated large-area four-point probe measurements. The designs for conversion of a RepRap 3-D printer to a 2-D open source four-point probe (OS4PP) measurement device are detailed for the mechanical and electrical systems. Free and open source software and firmware are developed to operate the tool. The OS4PP was validated against a wide range of discrete resistors and indium tin oxide (ITO) samples of different thicknesses both pre- and post-annealing. The OS4PP was then compared to two commercial proprietary systems. Results of resistors from 10 to 1 MΩ show errors of less than 1% for the OS4PP. The 3-D mapping of sheet resistance of ITO samples successfully demonstrated the automated capability to measure non-uniformities in large-area samples. The results indicate that all measured values are within the same order of magnitude when compared to two proprietary measurement systems. In conclusion, the OS4PP system, which costs less than 70% of manual proprietary systems, is comparable electrically while offering automated 100 micron positional accuracy for measuring sheet resistance over larger areas.

Open-Source Automated Mapping Four-Point Probe

PubMed Central

Chandra, Handy; Allen, Spencer W.; Oberloier, Shane W.; Bihari, Nupur; Gwamuri, Jephias; Pearce, Joshua M.

2017-01-01

Scientists have begun using self-replicating rapid prototyper (RepRap) 3-D printers to manufacture open source digital designs of scientific equipment. This approach is refined here to develop a novel instrument capable of performing automated large-area four-point probe measurements. The designs for conversion of a RepRap 3-D printer to a 2-D open source four-point probe (OS4PP) measurement device are detailed for the mechanical and electrical systems. Free and open source software and firmware are developed to operate the tool. The OS4PP was validated against a wide range of discrete resistors and indium tin oxide (ITO) samples of different thicknesses both pre- and post-annealing. The OS4PP was then compared to two commercial proprietary systems. Results of resistors from 10 to 1 MΩ show errors of less than 1% for the OS4PP. The 3-D mapping of sheet resistance of ITO samples successfully demonstrated the automated capability to measure non-uniformities in large-area samples. The results indicate that all measured values are within the same order of magnitude when compared to two proprietary measurement systems. In conclusion, the OS4PP system, which costs less than 70% of manual proprietary systems, is comparable electrically while offering automated 100 micron positional accuracy for measuring sheet resistance over larger areas. PMID:28772471

Point sources from dissipative dark matter

NASA Astrophysics Data System (ADS)

Agrawal, Prateek; Randall, Lisa

2017-12-01

If a component of dark matter has dissipative interactions, it can cool to form compact astrophysical objects with higher density than that of conventional cold dark matter (sub)haloes. Dark matter annihilations might then appear as point sources, leading to novel morphology for indirect detection. We explore dissipative models where interaction with the Standard Model might provide visible signals, and show how such objects might give rise to the observed excess in gamma rays arising from the galactic center.

Extended- and Point-Source Radiometric Program

DTIC Science & Technology

1962-08-08

aircraft of the U. S. Geo- logical Survey (USGS). Because many sites involved in nuclear activities exist and more are coming into exist- ence, the need of...GZ in Fig. 1.3 was the Ground Zero point of an old nuclear detonation and, unfortunately, was still highly radioactive. The detail of the source...measurements are the most dependable since the instrument was calibrated with Cs 137, Co 6°, and radium at a distance that gave a scattering component

Correcting STIS CCD Point-Source Spectra for CTE Loss

NASA Technical Reports Server (NTRS)

Goudfrooij, Paul; Bohlin, Ralph C.; Maiz-Apellaniz, Jesus

2006-01-01

We review the on-orbit spectroscopic observations that are being used to characterize the Charge Transfer Efficiency (CTE) of the STIS CCD in spectroscopic mode. We parameterize the CTE-related loss for spectrophotometry of point sources in terms of dependencies on the brightness of the source, the background level, the signal in the PSF outside the standard extraction box, and the time of observation. Primary constraints on our correction algorithm are provided by measurements of the CTE loss rates for simulated spectra (images of a tungsten lamp taken through slits oriented along the dispersion axis) combined with estimates of CTE losses for actual spectra of spectrophotometric standard stars in the first order CCD modes. For point-source spectra at the standard reference position at the CCD center, CTE losses as large as 30% are corrected to within approx.1% RMS after application of the algorithm presented here, rendering the Poisson noise associated with the source detection itself to be the dominant contributor to the total flux calibration uncertainty.

Point source detection in infrared astronomical surveys

NASA Technical Reports Server (NTRS)

Pelzmann, R. F., Jr.

1977-01-01

Data processing techniques useful for infrared astronomy data analysis systems are reported. This investigation is restricted to consideration of data from space-based telescope systems operating as survey instruments. In this report the theoretical background for specific point-source detection schemes is completed, and the development of specific algorithms and software for the broad range of requirements is begun.

A guide to differences between stochastic point-source and stochastic finite-fault simulations

USGS Publications Warehouse

Atkinson, G.M.; Assatourians, K.; Boore, D.M.; Campbell, K.; Motazedian, D.

2009-01-01

Why do stochastic point-source and finite-fault simulation models not agree on the predicted ground motions for moderate earthquakes at large distances? This question was posed by Ken Campbell, who attempted to reproduce the Atkinson and Boore (2006) ground-motion prediction equations for eastern North America using the stochastic point-source program SMSIM (Boore, 2005) in place of the finite-source stochastic program EXSIM (Motazedian and Atkinson, 2005) that was used by Atkinson and Boore (2006) in their model. His comparisons suggested that a higher stress drop is needed in the context of SMSIM to produce an average match, at larger distances, with the model predictions of Atkinson and Boore (2006) based on EXSIM; this is so even for moderate magnitudes, which should be well-represented by a point-source model. Why? The answer to this question is rooted in significant differences between point-source and finite-source stochastic simulation methodologies, specifically as implemented in SMSIM (Boore, 2005) and EXSIM (Motazedian and Atkinson, 2005) to date. Point-source and finite-fault methodologies differ in general in several important ways: (1) the geometry of the source; (2) the definition and application of duration; and (3) the normalization of finite-source subsource summations. Furthermore, the specific implementation of the methods may differ in their details. The purpose of this article is to provide a brief overview of these differences, their origins, and implications. This sets the stage for a more detailed companion article, "Comparing Stochastic Point-Source and Finite-Source Ground-Motion Simulations: SMSIM and EXSIM," in which Boore (2009) provides modifications and improvements in the implementations of both programs that narrow the gap and result in closer agreement. These issues are important because both SMSIM and EXSIM have been widely used in the development of ground-motion prediction equations and in modeling the parameters that control

Multi-rate, real time image compression for images dominated by point sources

NASA Technical Reports Server (NTRS)

Huber, A. Kris; Budge, Scott E.; Harris, Richard W.

1993-01-01

An image compression system recently developed for compression of digital images dominated by point sources is presented. Encoding consists of minimum-mean removal, vector quantization, adaptive threshold truncation, and modified Huffman encoding. Simulations are presented showing that the peaks corresponding to point sources can be transmitted losslessly for low signal-to-noise ratios (SNR) and high point source densities while maintaining a reduced output bit rate. Encoding and decoding hardware has been built and tested which processes 552,960 12-bit pixels per second at compression rates of 10:1 and 4:1. Simulation results are presented for the 10:1 case only.

A Search for Point Sources of EeV Photons

NASA Astrophysics Data System (ADS)

Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Peķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Thao, N. T.; Theodoro, V. M.; Tiffenberg, J.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Whelan, B. J.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Auger Collaboration102, The Pierre

2014-07-01

Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85° to +20°, in an energy range from 1017.3 eV to 1018.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm-2 s-1, and no celestial direction exceeds 0.25 eV cm-2 s-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.

Determination of efficiency of an aged HPGe detector for gaseous sources by self absorption correction and point source methods

NASA Astrophysics Data System (ADS)

Sarangapani, R.; Jose, M. T.; Srinivasan, T. K.; Venkatraman, B.

2017-07-01

Methods for the determination of efficiency of an aged high purity germanium (HPGe) detector for gaseous sources have been presented in the paper. X-ray radiography of the detector has been performed to get detector dimensions for computational purposes. The dead layer thickness of HPGe detector has been ascertained from experiments and Monte Carlo computations. Experimental work with standard point and liquid sources in several cylindrical geometries has been undertaken for obtaining energy dependant efficiency. Monte Carlo simulations have been performed for computing efficiencies for point, liquid and gaseous sources. Self absorption correction factors have been obtained using mathematical equations for volume sources and MCNP simulations. Self-absorption correction and point source methods have been used to estimate the efficiency for gaseous sources. The efficiencies determined from the present work have been used to estimate activity of cover gas sample of a fast reactor.

Better Assessment Science Integrating Point and Nonpoint Sources

EPA Science Inventory

Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) is not a model per se, but is a multipurpose environmental decision support system for use by regional, state, and local agencies in performing watershed- and water-quality-based studies. BASI...

Investigation of the Hosgri Fault, offshore Southern California, Point Sal to Point Conception

USGS Publications Warehouse

Payne, C.M.; Swanson, O.E.; Schell, B.A.

1979-01-01

A high-resolution seismic reflection survey of the inner continental shelf between Point Sal and Point Conception has revealed faults that displace post-Wisconsin strata (less than 17,000-20,000 years). These faults are the Hosgri fault, the Offshore Lompoc fault, and smaller unnamed faults. Faults trending offshore from the adjacent shoreline such as the Pezzoni, Lions Head, Honda, and Pacifico faults, do not show post-Wisconsin activity. The Hosgri fault trends directly toward the coastline between Purisima Point and Point Arguello where it appears to merge with folds and smaller faults in the western Transverse Ranges. This trend of offshore structures toward the Point Arguello-Point Conception area is consistent with a hypothesis that the regional structural fabric of the southern California Coast Ranges and its adjacent offshore area merge with the Transverse Ranges.

Modeling deep brain stimulation: point source approximation versus realistic representation of the electrode

NASA Astrophysics Data System (ADS)

Zhang, Tianhe C.; Grill, Warren M.

2010-12-01

Deep brain stimulation (DBS) has emerged as an effective treatment for movement disorders; however, the fundamental mechanisms by which DBS works are not well understood. Computational models of DBS can provide insights into these fundamental mechanisms and typically require two steps: calculation of the electrical potentials generated by DBS and, subsequently, determination of the effects of the extracellular potentials on neurons. The objective of this study was to assess the validity of using a point source electrode to approximate the DBS electrode when calculating the thresholds and spatial distribution of activation of a surrounding population of model neurons in response to monopolar DBS. Extracellular potentials in a homogenous isotropic volume conductor were calculated using either a point current source or a geometrically accurate finite element model of the Medtronic DBS 3389 lead. These extracellular potentials were coupled to populations of model axons, and thresholds and spatial distributions were determined for different electrode geometries and axon orientations. Median threshold differences between DBS and point source electrodes for individual axons varied between -20.5% and 9.5% across all orientations, monopolar polarities and electrode geometries utilizing the DBS 3389 electrode. Differences in the percentage of axons activated at a given amplitude by the point source electrode and the DBS electrode were between -9.0% and 12.6% across all monopolar configurations tested. The differences in activation between the DBS and point source electrodes occurred primarily in regions close to conductor-insulator interfaces and around the insulating tip of the DBS electrode. The robustness of the point source approximation in modeling several special cases—tissue anisotropy, a long active electrode and bipolar stimulation—was also examined. Under the conditions considered, the point source was shown to be a valid approximation for predicting excitation

Universal energy spectrum from point sources

NASA Technical Reports Server (NTRS)

Tomozawa, Yukio

1992-01-01

The suggestion is made that the energy spectrum from point sources such as galactic black hole candidates (GBHC) and active galactic nuclei (AGN) is universal on the average, irrespective of the species of the emitted particles, photons, nucleons, or others. The similarity between the observed energy spectra of cosmic rays, gamma-rays, and X-rays is discussed. In other words, the existing data for gamma-rays and X-rays seem to support the prediction. The expected data from the Gamma Ray Observatory are to provide a further test.

Outdoor air pollution in close proximity to a continuous point source

NASA Astrophysics Data System (ADS)

Klepeis, Neil E.; Gabel, Etienne B.; Ott, Wayne R.; Switzer, Paul

Data are lacking on human exposure to air pollutants occurring in ground-level outdoor environments within a few meters of point sources. To better understand outdoor exposure to tobacco smoke from cigarettes or cigars, and exposure to other types of outdoor point sources, we performed more than 100 controlled outdoor monitoring experiments on a backyard residential patio in which we released pure carbon monoxide (CO) as a tracer gas for continuous time periods lasting 0.5-2 h. The CO was emitted from a single outlet at a fixed per-experiment rate of 120-400 cc min -1 (˜140-450 mg min -1). We measured CO concentrations every 15 s at up to 36 points around the source along orthogonal axes. The CO sensors were positioned at standing or sitting breathing heights of 2-5 ft (up to 1.5 ft above and below the source) and at horizontal distances of 0.25-2 m. We simultaneously measured real-time air speed, wind direction, relative humidity, and temperature at single points on the patio. The ground-level air speeds on the patio were similar to those we measured during a survey of 26 outdoor patio locations in 5 nearby towns. The CO data exhibited a well-defined proximity effect similar to the indoor proximity effect reported in the literature. Average concentrations were approximately inversely proportional to distance. Average CO levels were approximately proportional to source strength, supporting generalization of our results to different source strengths. For example, we predict a cigarette smoker would cause average fine particle levels of approximately 70-110 μg m -3 at horizontal distances of 0.25-0.5 m. We also found that average CO concentrations rose significantly as average air speed decreased. We fit a multiplicative regression model to the empirical data that predicts outdoor concentrations as a function of source emission rate, source-receptor distance, air speed and wind direction. The model described the data reasonably well, accounting for ˜50% of the log

Long Term Temporal and Spectral Evolution of Point Sources in Nearby Elliptical Galaxies

NASA Astrophysics Data System (ADS)

Durmus, D.; Guver, T.; Hudaverdi, M.; Sert, H.; Balman, Solen

2016-06-01

We present the results of an archival study of all the point sources detected in the lines of sight of the elliptical galaxies NGC 4472, NGC 4552, NGC 4649, M32, Maffei 1, NGC 3379, IC 1101, M87, NGC 4477, NGC 4621, and NGC 5128, with both the Chandra and XMM-Newton observatories. Specifically, we studied the temporal and spectral evolution of these point sources over the course of the observations of the galaxies, mostly covering the 2000 - 2015 period. In this poster we present the first results of this study, which allows us to further constrain the X-ray source population in nearby elliptical galaxies and also better understand the nature of individual point sources.

An External Matrix-Assisted Laser Desorption Ionization Source for Flexible FT-ICR Mass Spectrometry Imaging with Internal Calibration on Adjacent Samples

NASA Astrophysics Data System (ADS)

Smith, Donald F.; Aizikov, Konstantin; Duursma, Marc C.; Giskes, Frans; Spaanderman, Dirk-Jan; McDonnell, Liam A.; O'Connor, Peter B.; Heeren, Ron M. A.

2011-01-01

We describe the construction and application of a new MALDI source for FT-ICR mass spectrometry imaging. The source includes a translational X-Y positioning stage with a 10 × 10 cm range of motion for analysis of large sample areas, a quadrupole for mass selection, and an external octopole ion trap with electrodes for the application of an axial potential gradient for controlled ion ejection. An off-line LC MALDI MS/MS run demonstrates the utility of the new source for data- and position-dependent experiments. A FT-ICR MS imaging experiment of a coronal rat brain section yields ˜200 unique peaks from m/z 400-1100 with corresponding mass-selected images. Mass spectra from every pixel are internally calibrated with respect to polymer calibrants collected from an adjacent slide.

Temporal variability in domestic point source discharges and their associated impact on receiving waters.

PubMed

Richards, Samia; Withers, Paul J A; Paterson, Eric; McRoberts, Colin W; Stutter, Marc

2016-11-15

Discharges from the widely distributed small point sources of pollutants such as septic tanks contribute to microbial and nutrient loading of streams and can pose risks to human health and stream ecology, especially during periods of ecological sensitivity. Here we present the first comprehensive data on the compositional variability of septic tank effluents (STE) as a potential source of water pollution during different seasons and the associated links to their influence on stream waters. To determine STE parameters and nutrient variations, the biological and physicochemical properties of effluents sampled quarterly from 12 septic tank systems were investigated with concurrent analyses of upstream and downstream receiving waters. The study revealed that during the warmer dryer months of spring and summer, effluents were similar in composition, as were the colder wetter months of autumn and winter. However, spring/summer effluents differed significantly (P<0.05) from autumn/winter for concentrations of biological oxygen demand (BOD), arsenic, barium (Ba), cobalt, chromium, manganese, strontium (Sr), titanium, tungsten (W) and zinc (Zn). With the exception of BOD, Ba and Sr which were greater in summer and spring, the concentrations of these parameters were greater in winter. Receiving stream waters also showed significant seasonal variation (P≤0.05) in alkalinity, BOD, dissolved organic carbon, sulphate, sulphur, lithium, W, Zn and Escherichiacoli abundance. There was a clear significant influence of STE on downstream waters relative to upstream from the source (P<0.05) for total suspended solids, total particulate P and N, ammonium-N, coliforms and E. coli. The findings of this study found seasonal variation in STE and place effluent discharges as a factor affecting adjacent stream quality and call for appropriate measures to reduce or redirect STE discharges away from water courses. Copyright © 2016 Elsevier B.V. All rights reserved.

Providing nearest neighbor point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

DOEpatents

Archer, Charles J.; Faraj, Ahmad A.; Inglett, Todd A.; Ratterman, Joseph D.

2012-10-23

Methods, apparatus, and products are disclosed for providing nearest neighbor point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: identifying each link in the global combining network for each compute node of the operational group; designating one of a plurality of point-to-point class routing identifiers for each link such that no compute node in the operational group is connected to two adjacent compute nodes in the operational group with links designated for the same class routing identifiers; and configuring each compute node of the operational group for point-to-point communications with each adjacent compute node in the global combining network through the link between that compute node and that adjacent compute node using that link's designated class routing identifier.

Testing wetland axioms at a watershed scale: Case studies of the aggregate hydrologic effects of non-adjacent wetlands

EPA Science Inventory

Wetlands not adjacent to streams (i.e. “non-adjacent wetlands”) are hypothesized to affect downgradient hydrology in a number of ways. Non-adjacent wetlands may, for example, attenuate peak flows, serve as focal points for groundwater recharge, and decrease streamflow...

33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights. (b...

33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights. (b...

33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights. (b...

33 CFR 165.1303 - Puget Sound and adjacent waters, WA-regulated navigation area.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... § 165.1303 Puget Sound and adjacent waters, WA—regulated navigation area. (a) The following is a... Light to New Dungeness Light and all points in the Puget Sound area north and south of these lights. (b...

An efficient method to compute microlensed light curves for point sources

NASA Technical Reports Server (NTRS)

Witt, Hans J.

1993-01-01

We present a method to compute microlensed light curves for point sources. This method has the general advantage that all microimages contributing to the light curve are found. While a source moves along a straight line, all micro images are located either on the primary image track or on the secondary image tracks (loops). The primary image track extends from - infinity to + infinity and is made of many sequents which are continuously connected. All the secondary image tracks (loops) begin and end on the lensing point masses. The method can be applied to any microlensing situation with point masses in the deflector plane, even for the overcritical case and surface densities close to the critical. Furthermore, we present general rules to evaluate the light curve for a straight track arbitrary placed in the caustic network of a sample of many point masses.

The resolution of point sources of light as analyzed by quantum detection theory

NASA Technical Reports Server (NTRS)

Helstrom, C. W.

1972-01-01

The resolvability of point sources of incoherent light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

First Neutrino Point-Source Results from the 22 String Icecube Detector

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Breder, D.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Day, C. T.; De Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; De Young, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Heise, J.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Klepser, S.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Leich, H.; Lennarz, D.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Merck, M.; Mészáros, P.; Middell, E.; Milke, N.; Miyamoto, H.; Mohr, A.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Pérez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Satalecka, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; Voigt, B.; Walck, C.; Waldenmaier, T.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebusch, C. H.; Wiedemann, A.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Ice Cube Collaboration

2009-08-01

We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-2008 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of live time. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2σ after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E -2 spectrum is E^{2} Φ_{ν_{μ}} < 1.4 × 10^{-11} TeV cm^{-2} s^{-1}, in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of 2.

An infrared sky model based on the IRAS point source data

NASA Technical Reports Server (NTRS)

Cohen, Martin; Walker, Russell; Wainscoat, Richard; Volk, Kevin; Walker, Helen; Schwartz, Deborah

1990-01-01

A detailed model for the infrared point source sky is presented that comprises geometrically and physically realistic representations of the galactic disk, bulge, spheroid, spiral arms, molecular ring, and absolute magnitudes. The model was guided by a parallel Monte Carlo simulation of the Galaxy. The content of the galactic source table constitutes an excellent match to the 12 micrometer luminosity function in the simulation, as well as the luminosity functions at V and K. Models are given for predicting the density of asteroids to be observed, and the diffuse background radiance of the Zodiacal cloud. The model can be used to predict the character of the point source sky expected for observations from future infrared space experiments.

Interferometry with flexible point source array for measuring complex freeform surface and its design algorithm

NASA Astrophysics Data System (ADS)

Li, Jia; Shen, Hua; Zhu, Rihong; Gao, Jinming; Sun, Yue; Wang, Jinsong; Li, Bo

2018-06-01

The precision of the measurements of aspheric and freeform surfaces remains the primary factor restrict their manufacture and application. One effective means of measuring such surfaces involves using reference or probe beams with angle modulation, such as tilted-wave-interferometer (TWI). It is necessary to improve the measurement efficiency by obtaining the optimum point source array for different pieces before TWI measurements. For purpose of forming a point source array based on the gradients of different surfaces under test, we established a mathematical model describing the relationship between the point source array and the test surface. However, the optimal point sources are irregularly distributed. In order to achieve a flexible point source array according to the gradient of test surface, a novel interference setup using fiber array is proposed in which every point source can be independently controlled on and off. Simulations and the actual measurement examples of two different surfaces are given in this paper to verify the mathematical model. Finally, we performed an experiment of testing an off-axis ellipsoidal surface that proved the validity of the proposed interference system.

SPARROW modeling of nitrogen sources and transport in rivers and streams of California and adjacent states, U.S.

USGS Publications Warehouse

Saleh, Dina; Domagalski, Joseph L.

2015-01-01

The SPARROW (SPAtially Referenced Regressions On Watershed attributes) model was used to evaluate the spatial distribution of total nitrogen (TN) sources, loads, watershed yields, and factors affecting transport and decay in the stream network of California and portions of adjacent states for the year 2002. The two major TN sources to local catchments on a mass basis were fertilizers and manure (51.7%) and wastewater discharge (15.9%). Other sources contributed < 12%. Fertilizer use is widespread in the Central Valley region of California, and also important in several other regions because of the diversity of California agriculture. Precipitation, sand content of surficial soils, wetlands, and tile drains were important for TN movement to stream reaches. Median streamflow in the study area is about 0.04 m3/s. Aquatic losses of nitrogen were found to be most important in intermittent and small to medium sized streams (0.2-14 m3/s), while larger streams showed less loss, and therefore are important for TN transport. Nitrogen loss in reservoirs was found to be insignificant, possibly because most of the larger ones are located upstream of nitrogen sources. The model was used to show loadings, sources, and tributary inputs to several major rivers. The information provided by the SPARROW model is useful for determining both the major sources contributing nitrogen to streams and the specific tributaries that transport the load.

The distribution of infrared point sources in nearby elliptical galaxies

NASA Astrophysics Data System (ADS)

Gogoi, Rupjyoti; Shalima, P.; Misra, Ranjeev

2018-02-01

Infrared (IR) point sources as observed by Spitzer, in nearby early-type galaxies should either be bright sources in the galaxy such as globular clusters, or they may be background sources such as AGNs. These objects are often counterparts of sources in other wavebands such as optical and X-rays and the IR information provides crucial information regarding their nature. However, many of the IR sources may be background objects and it is important to identify them or at least quantify the level of background contamination. Moreover, the distribution of these IR point sources in flux, distance from the centre and colour would be useful in understanding their origin. Archival Spitzer IRAC images provide a unique opportunity for such a study and here we present the results of such an analysis for four nearby galaxies, NGC 1399, NGC 2768, NGC 4365 and NGC 4649. We estimate the background contamination using several blank fields. Our results suggest that IR colours can be effectively used to differentiate between sources in the galaxy and background ones. In particular we find that sources having AGN like colours are indeed consistent with being background AGNs. For sources with non AGN like colours we compute the distribution of flux and normalised distance from the centre which is found to be of a power-law form. Although our sample size is small, the power-law index for the galaxies are different indicating perhaps that the galaxy environment may be playing a part in their origin and nature.

THE CHANDRA COSMOS SURVEY. I. OVERVIEW AND POINT SOURCE CATALOG

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

Elvis, Martin; Civano, Francesca; Aldcroft, T. L.

2009-09-01

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.5 deg{sup 2} of the COSMOS field (centered at 10 {sup h}, +02 deg.) with an effective exposure of {approx}160 ks, and an outer 0.4 deg{sup 2} area with an effective exposure of {approx}80 ks. The limiting source detection depths are 1.9 x 10{sup -16} erg cm{sup -2} s{sup -1} in the soft (0.5-2 keV) band, 7.3 x 10{sup -16} erg cm{sup -2} s{sup -1} in the hard (2-10 keV) band, and 5.7 x 10{sup -16} erg cm{sup -2} s{sup -1} in themore » full (0.5-10 keV) band. Here we describe the strategy, design, and execution of the C-COSMOS survey, and present the catalog of 1761 point sources detected at a probability of being spurious of <2 x 10{sup -5} (1655 in the full, 1340 in the soft, and 1017 in the hard bands). By using a grid of 36 heavily ({approx}50%) overlapping pointing positions with the ACIS-I imager, a remarkably uniform ({+-}12%) exposure across the inner 0.5 deg{sup 2} field was obtained, leading to a sharply defined lower flux limit. The widely different point-spread functions obtained in each exposure at each point in the field required a novel source detection method, because of the overlapping tiling strategy, which is described in a companion paper. This method produced reliable sources down to a 7-12 counts, as verified by the resulting logN-logS curve, with subarcsecond positions, enabling optical and infrared identifications of virtually all sources, as reported in a second companion paper. The full catalog is described here in detail and is available online.« less

Adjustable long duration high-intensity point light source

NASA Astrophysics Data System (ADS)

Krehl, P.; Hagelweide, J. B.

1981-06-01

A new long duration high-intensity point light source with adjustable light duration and a small light spot locally stable in time has been developed. The principle involved is a stationary high-temperature plasma flow inside a partly constrained capillary of a coaxial spark gap which is viewed end on through a terminating Plexiglas window. The point light spark gap is operated via a resistor by an artificial transmission line. Using two exchangeable inductance sets in the line, two ranges of photoduration 10-130 μs and 100-600 μs can be covered. For a light spot size of 1.5 mm diameter the corresponding peak light output amounts to 5×106 and 1.6×106 candelas, respectively. Within these ranges the duration is controlled by an ignitron crowbar to extinguish the plasma. The adjustable photoduration is very useful for the application of continuous writing rotating mirror cameras, thus preventing multiple exposures. The essentially uniform exposure within the visible spectral range makes the new light source suitable for color cinematography.

Incentive Analysis for Clean Water Act Reauthorization: Point Source/Nonpoint Source Trading for Nutrient Discharge Reductions (1992)

EPA Pesticide Factsheets

Paper focuses on trading schemes in which regulated point sources are allowed to avoid upgrading their pollution control technology to meet water quality-based effluent limits if they pay for equivalent (or greater) reductions in nonpoint source pollution.

Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

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

Lee, Samuel K.; Lisanti, Mariangela; Safdi, Benjamin R., E-mail: samuelkl@princeton.edu, E-mail: mlisanti@princeton.edu, E-mail: bsafdi@princeton.edu

2015-05-01

Data from the Fermi Large Area Telescope suggests that there is an extended excess of GeV gamma-ray photons in the Inner Galaxy. Identifying potential astrophysical sources that contribute to this excess is an important step in verifying whether the signal originates from annihilating dark matter. In this paper, we focus on the potential contribution of unresolved point sources, such as millisecond pulsars (MSPs). We propose that the statistics of the photons—in particular, the flux probability density function (PDF) of the photon counts below the point-source detection threshold—can potentially distinguish between the dark-matter and point-source interpretations. We calculate the flux PDFmore » via the method of generating functions for these two models of the excess. Working in the framework of Bayesian model comparison, we then demonstrate that the flux PDF can potentially provide evidence for an unresolved MSP-like point-source population.« less

A model of the 8-25 micron point source infrared sky

NASA Technical Reports Server (NTRS)

Wainscoat, Richard J.; Cohen, Martin; Volk, Kevin; Walker, Helen J.; Schwartz, Deborah E.

1992-01-01

We present a detailed model for the IR point-source sky that comprises geometrically and physically realistic representations of the Galactic disk, bulge, stellar halo, spiral arms (including the 'local arm'), molecular ring, and the extragalactic sky. We represent each of the distinct Galactic components by up to 87 types of Galactic source, each fully characterized by scale heights, space densities, and absolute magnitudes at BVJHK, 12, and 25 microns. The model is guided by a parallel Monte Carlo simulation of the Galaxy at 12 microns. The content of our Galactic source table constitutes a good match to the 12 micron luminosity function in the simulation, as well as to the luminosity functions at V and K. We are able to produce differential and cumulative IR source counts for any bandpass lying fully within the IRAS Low-Resolution Spectrometer's range (7.7-22.7 microns as well as for the IRAS 12 and 25 micron bands. These source counts match the IRAS observations well. The model can be used to predict the character of the point source sky expected for observations from IR space experiments.

Interior building details of Building A, dungeon cell adjacent to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior building details of Building A, dungeon cell adjacent to northwest cell: granite and brick threshold, poured concrete floors, plastered finished walls, vaulted veiling; northwesterly view - San Quentin State Prison, Building 22, Point San Quentin, San Quentin, Marin County, CA

TMDLS: AFTER POINT SOURCES, WHAT CAN WE DO NEXT?

EPA Science Inventory

Section 303(d) of the Clean Water Act required TMDLs (total maximum daily loads) for all waters for which effluent or point source limitations are insufficient to meet water quality standards. Concerns may arise regarding the manner by which TMDLs are established, the corrective ...

Search for point sources of high energy neutrinos with Amanda

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

Ahrens, J.

2002-08-01

Report of search for likely point sources for neutrinos observed by the Amanda detector. Places intensity limits on observable point sources. This paper describes the search for astronomical sources of high-energy neutrinos using the AMANDA-B10 detector, an array of 302 photomultiplier tubes, used for the detection of Cherenkov light from upward traveling neutrino-induced muons, buried deep in ice at the South Pole. The absolute pointing accuracy and angular resolution were studied by using coincident events between the AMANDA detector and two independent telescopes on the surface, the GASP air Cherenkov telescope and the SPASE extensive air shower array. Using datamore » collected from April to October of 1997 (130.1 days of livetime), a general survey of the northern hemisphere revealed no statistically significant excess of events from any direction. The sensitivity for a flux of muon neutrinos is based on the effective detection area for through-going muons. Averaged over the Northern sky, the effective detection area exceeds 10,000 m{sup 2} for E{sub {mu}} {approx} 10 TeV. Neutrinos generated in the atmosphere by cosmic ray interactions were used to verify the predicted performance of the detector. For a source with a differential energy spectrum proportional to E{sub {nu}}{sup -2} and declination larger than +40{sup o}, we obtain E{sup 2} (dN{sub {nu}}/dE) {le} 10{sup -6} GeV cm{sup -2} s{sup -1} for an energy threshold of 10 GeV.« less

THE SPITZER-IRAC POINT-SOURCE CATALOG OF THE VELA-D CLOUD

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

Strafella, F.; Elia, D.; Campeggio, L., E-mail: francesco.strafella@le.infn.i, E-mail: loretta.campeggio@le.infn.i, E-mail: eliad@oal.ul.p

2010-08-10

This paper presents the observations of Cloud D in the Vela Molecular Ridge, obtained with the Infrared Array Camera (IRAC) camera on board the Spitzer Space Telescope at the wavelengths {lambda} = 3.6, 4.5, 5.8, and 8.0 {mu}m. A photometric catalog of point sources, covering a field of approximately 1.2 deg{sup 2}, has been extracted and complemented with additional available observational data in the millimeter region. Previous observations of the same region, obtained with the Spitzer MIPS camera in the photometric bands at 24 {mu}m and 70 {mu}m, have also been reconsidered to allow an estimate of the spectral slopemore » of the sources in a wider spectral range. A total of 170,299 point sources, detected at the 5{sigma} sensitivity level in at least one of the IRAC bands, have been reported in the catalog. There were 8796 sources for which good quality photometry was obtained in all four IRAC bands. For this sample, a preliminary characterization of the young stellar population based on the determination of spectral slope is discussed; combining this with diagnostics in the color-magnitude and color-color diagrams, the relative population of young stellar objects (YSOs) in different evolutionary classes has been estimated and a total of 637 candidate YSOs have been selected. The main differences in their relative abundances have been highlighted and a brief account for their spatial distribution is given. The star formation rate has also been estimated and compared with the values derived for other star-forming regions. Finally, an analysis of the spatial distribution of the sources by means of the two-point correlation function shows that the younger population, constituted by the Class I and flat-spectrum sources, is significantly more clustered than the Class II and III sources.« less

The Spitzer-IRAC Point-source Catalog of the Vela-D Cloud

NASA Astrophysics Data System (ADS)

Strafella, F.; Elia, D.; Campeggio, L.; Giannini, T.; Lorenzetti, D.; Marengo, M.; Smith, H. A.; Fazio, G.; De Luca, M.; Massi, F.

2010-08-01

This paper presents the observations of Cloud D in the Vela Molecular Ridge, obtained with the Infrared Array Camera (IRAC) camera on board the Spitzer Space Telescope at the wavelengths λ = 3.6, 4.5, 5.8, and 8.0 μm. A photometric catalog of point sources, covering a field of approximately 1.2 deg2, has been extracted and complemented with additional available observational data in the millimeter region. Previous observations of the same region, obtained with the Spitzer MIPS camera in the photometric bands at 24 μm and 70 μm, have also been reconsidered to allow an estimate of the spectral slope of the sources in a wider spectral range. A total of 170,299 point sources, detected at the 5σ sensitivity level in at least one of the IRAC bands, have been reported in the catalog. There were 8796 sources for which good quality photometry was obtained in all four IRAC bands. For this sample, a preliminary characterization of the young stellar population based on the determination of spectral slope is discussed; combining this with diagnostics in the color-magnitude and color-color diagrams, the relative population of young stellar objects (YSOs) in different evolutionary classes has been estimated and a total of 637 candidate YSOs have been selected. The main differences in their relative abundances have been highlighted and a brief account for their spatial distribution is given. The star formation rate has also been estimated and compared with the values derived for other star-forming regions. Finally, an analysis of the spatial distribution of the sources by means of the two-point correlation function shows that the younger population, constituted by the Class I and flat-spectrum sources, is significantly more clustered than the Class II and III sources.

Neural network simulation of the atmospheric point spread function for the adjacency effect research

NASA Astrophysics Data System (ADS)

Ma, Xiaoshan; Wang, Haidong; Li, Ligang; Yang, Zhen; Meng, Xin

2016-10-01

Adjacency effect could be regarded as the convolution of the atmospheric point spread function (PSF) and the surface leaving radiance. Monte Carlo is a common method to simulate the atmospheric PSF. But it can't obtain analytic expression and the meaningful results can be only acquired by statistical analysis of millions of data. A backward Monte Carlo algorithm was employed to simulate photon emitting and propagating in the atmosphere under different conditions. The PSF was determined by recording the photon-receiving numbers in fixed bin at different position. A multilayer feed-forward neural network with a single hidden layer was designed to learn the relationship between the PSF's and the input condition parameters. The neural network used the back-propagation learning rule for training. Its input parameters involved atmosphere condition, spectrum range, observing geometry. The outputs of the network were photon-receiving numbers in the corresponding bin. Because the output units were too many to be allowed by neural network, the large network was divided into a collection of smaller ones. These small networks could be ran simultaneously on many workstations and/or PCs to speed up the training. It is important to note that the simulated PSF's by Monte Carlo technique in non-nadir viewing angles are more complicated than that in nadir conditions which brings difficulties in the design of the neural network. The results obtained show that the neural network approach could be very useful to compute the atmospheric PSF based on the simulated data generated by Monte Carlo method.

Distributed Sensing for Quickest Change Detection of Point Radiation Sources

DTIC Science & Technology

2017-02-01

point occurs simultaneously at all sensor nodes, thus neglecting signal propagation delays. For nuclear radiation , the observation period, which is on... nuclear radiation using a sensor network,” in Homeland Security (HST), 2012 IEEE Conference on Technologies for. IEEE, 2012, pp. 648–653. [8] G. Lorden...Distributed Sensing for Quickest Change Detection of Point Radiation Sources Gene T. Whipps⋆† Emre Ertin† Randolph L. Moses† †The Ohio State

Controllability of semi-infinite rod heating by a point source

NASA Astrophysics Data System (ADS)

Khurshudyan, A.

2018-04-01

The possibility of control over heating of a semi-infinite thin rod by a point source concentrated at an inner point of the rod, is studied. Quadratic and piecewise constant solutions of the problem are derived, and the possibilities of solving appropriate problems of optimal control are indicated. Determining of the parameters of the piecewise constant solution is reduced to a problem of nonlinear programming. Numerical examples are considered.

Studies of acoustic emission from point and extended sources

NASA Technical Reports Server (NTRS)

Sachse, W.; Kim, K. Y.; Chen, C. P.

1986-01-01

The use of simulated and controlled acoustic emission signals forms the basis of a powerful tool for the detailed study of various deformation and wave interaction processes in materials. The results of experiments and signal analyses of acoustic emission resulting from point sources such as various types of indentation-produced cracks in brittle materials and the growth of fatigue cracks in 7075-T6 aluminum panels are discussed. Recent work dealing with the modeling and subsequent signal processing of an extended source of emission in a material is reviewed. Results of the forward problem and the inverse problem are presented with the example of a source distributed through the interior of a specimen.

Extending the Search for Neutrino Point Sources with IceCube above the Horizon

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Alba, J. L. Bazo; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Botner, O.; Bradley, L.; Braun, J.; Breder, D.; Carson, M.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Day, C. T.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lundberg, J.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miyamoto, H.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Paul, L.; de Los Heros, C. Pérez; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Toale, P. A.; Tooker, J.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wiedemann, A.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.

2009-11-01

Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.

A deeper look at the X-ray point source population of NGC 4472

NASA Astrophysics Data System (ADS)

Joseph, T. D.; Maccarone, T. J.; Kraft, R. P.; Sivakoff, G. R.

2017-10-01

In this paper we discuss the X-ray point source population of NGC 4472, an elliptical galaxy in the Virgo cluster. We used recent deep Chandra data combined with archival Chandra data to obtain a 380 ks exposure time. We find 238 X-ray point sources within 3.7 arcmin of the galaxy centre, with a completeness flux, FX, 0.5-2 keV = 6.3 × 10-16 erg s-1 cm-2. Most of these sources are expected to be low-mass X-ray binaries. We finding that, using data from a single galaxy which is both complete and has a large number of objects (˜100) below 1038 erg s-1, the X-ray luminosity function is well fitted with a single power-law model. By cross matching our X-ray data with both space based and ground based optical data for NGC 4472, we find that 80 of the 238 sources are in globular clusters. We compare the red and blue globular cluster subpopulations and find red clusters are nearly six times more likely to host an X-ray source than blue clusters. We show that there is evidence that these two subpopulations have significantly different X-ray luminosity distributions. Source catalogues for all X-ray point sources, as well as any corresponding optical data for globular cluster sources, are also presented here.

Selected metal levels of commercially valuable seaweeds adjacent to and distant from point sources of contamination in Nova Scotia and New Brunswick

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

Sharp, G.J.; Samant, H.S.; Vaidya, O.C.

1988-06-01

The harvesting of marine plants on a commercial scale was a significant industry in the Maritime Provinces of Canada by the end of World War II. These seaweeds have been traditionally utilized as foodstuffs either as a processed extract or a semi-processed plant. The Maritime coastline is becoming industrialized; there is also potential for expansion of the marine plant industry beyond traditional harvest areas. Therefore, the quality of material from new areas must be examined prior to exploitation as well as monitoring of traditional areas. The bioaccumulated of metals by marine plants was recognized in early measurements of trace elementmore » concentrations which were above ambient water values. Before growth and reproductive inhibition are caused by severe effects of heavy metal pollution, food quality changes may occur. The Food Chemical Code (U.S.A.) limits heavy metals in the extracts of seaweeds. Sediment and water samples taken in connection with the Ocean Dumping Control Act of Canada have identified several sites with elevated heavy metal content in the Maritimes. The purpose of this study was to examine heavy metal levels in commercially important seaweeds from traditional harvest areas and areas near point sources of pollution. The authors wished to provide a baseline for the future and identify existing problem areas.« less

Discrimination between diffuse and point sources of arsenic at Zimapán, Hidalgo state, Mexico.

PubMed

Sracek, Ondra; Armienta, María Aurora; Rodríguez, Ramiro; Villaseñor, Guadalupe

2010-01-01

There are two principal sources of arsenic in Zimapán. Point sources are linked to mining and smelting activities and especially to mine tailings. Diffuse sources are not well defined and are linked to regional flow systems in carbonate rocks. Both sources are caused by the oxidation of arsenic-rich sulfidic mineralization. Point sources are characterized by Ca-SO(4)-HCO(3) ground water type and relatively enriched values of deltaD, delta(18)O, and delta(34)S(SO(4)). Diffuse sources are characterized by Ca-Na-HCO(3) type of ground water and more depleted values of deltaD, delta(18)O, and delta(34)S(SO(4)). Values of deltaD and delta(18)O indicate similar altitude of recharge for both arsenic sources and stronger impact of evaporation for point sources in mine tailings. There are also different values of delta(34)S(SO(4)) for both sources, presumably due to different types of mineralization or isotopic zonality in deposits. In Principal Component Analysis (PCA), the principal component 1 (PC1), which describes the impact of sulfide oxidation and neutralization by the dissolution of carbonates, has higher values in samples from point sources. In spite of similar concentrations of As in ground water affected by diffuse sources and point sources (mean values 0.21 mg L(-1) and 0.31 mg L(-1), respectively, in the years from 2003 to 2008), the diffuse sources have more impact on the health of population in Zimapán. This is caused by the extraction of ground water from wells tapping regional flow system. In contrast, wells located in the proximity of mine tailings are not generally used for water supply.

Strong ground motion simulation of the 2016 Kumamoto earthquake of April 16 using multiple point sources

NASA Astrophysics Data System (ADS)

Nagasaka, Yosuke; Nozu, Atsushi

2017-02-01

The pseudo point-source model approximates the rupture process on faults with multiple point sources for simulating strong ground motions. A simulation with this point-source model is conducted by combining a simple source spectrum following the omega-square model with a path spectrum, an empirical site amplification factor, and phase characteristics. Realistic waveforms can be synthesized using the empirical site amplification factor and phase models even though the source model is simple. The Kumamoto earthquake occurred on April 16, 2016, with M JMA 7.3. Many strong motions were recorded at stations around the source region. Some records were considered to be affected by the rupture directivity effect. This earthquake was suitable for investigating the applicability of the pseudo point-source model, the current version of which does not consider the rupture directivity effect. Three subevents (point sources) were located on the fault plane, and the parameters of the simulation were determined. The simulated results were compared with the observed records at K-NET and KiK-net stations. It was found that the synthetic Fourier spectra and velocity waveforms generally explained the characteristics of the observed records, except for underestimation in the low frequency range. Troughs in the observed Fourier spectra were also well reproduced by placing multiple subevents near the hypocenter. The underestimation is presumably due to the following two reasons. The first is that the pseudo point-source model targets subevents that generate strong ground motions and does not consider the shallow large slip. The second reason is that the current version of the pseudo point-source model does not consider the rupture directivity effect. Consequently, strong pulses were not reproduced enough at stations northeast of Subevent 3 such as KMM004, where the effect of rupture directivity was significant, while the amplitude was well reproduced at most of the other stations. This

Water-quality, water-level, and lake-bottom-sediment data collected from the defense fuel supply point and adjacent properties, Hanahan, South Carolina, 1990-96

USGS Publications Warehouse

Petkewich, M.D.; Vroblesky, D.A.; Robertson, J.F.; Bradley, P.M.

1997-01-01

A 9-year scientific investigation to determine the potential for biore-mediation of ground-water contamination and to monitor the effectiveness of an engineered bioremediation system located at the Defense Fuel Supply Point and adjacent properties in Hanahan, S.C., has culminated in the collection of abundant water-quality and water-level data.This report presents the analytical results of the study that monitored the changes in surface- and ground-water quality and water-table elevations in the study area from December 1990 to January 1996. This report also presents analytical results of lake-bottom sediments collected in the study area.

Sampling Singular and Aggregate Point Sources of Carbon Dioxide from Space Using OCO-2

NASA Astrophysics Data System (ADS)

Schwandner, F. M.; Gunson, M. R.; Eldering, A.; Miller, C. E.; Nguyen, H.; Osterman, G. B.; Taylor, T.; O'Dell, C.; Carn, S. A.; Kahn, B. H.; Verhulst, K. R.; Crisp, D.; Pieri, D. C.; Linick, J.; Yuen, K.; Sanchez, R. M.; Ashok, M.

2016-12-01

Anthropogenic carbon dioxide (CO2) sources increasingly tip the natural balance between natural carbon sources and sinks. Space-borne measurements offer opportunities to detect and analyze point source emission signals anywhere on Earth. Singular continuous point source plumes from power plants or volcanoes turbulently mix into their proximal background fields. In contrast, plumes of aggregate point sources such as cities, and transportation or fossil fuel distribution networks, mix into each other and may therefore result in broader and more persistent excess signals of total column averaged CO2 (XCO2). NASA's first satellite dedicated to atmospheric CO2observation, the Orbiting Carbon Observatory-2 (OCO-2), launched in July 2014 and now leads the afternoon constellation of satellites (A-Train). While continuously collecting measurements in eight footprints across a narrow ( < 10 km) wide swath it occasionally cross-cuts coincident emission plumes. For singular point sources like volcanoes and coal fired power plants, we have developed OCO-2 data discovery tools and a proxy detection method for plumes using SO2-sensitive TIR imaging data (ASTER). This approach offers a path toward automating plume detections with subsequent matching and mining of OCO-2 data. We found several distinct singular source CO2signals. For aggregate point sources, we investigated whether OCO-2's multi-sounding swath observing geometry can reveal intra-urban spatial emission structures in the observed variability of XCO2 data. OCO-2 data demonstrate that we can detect localized excess XCO2 signals of 2 to 6 ppm against suburban and rural backgrounds. Compared to single-shot GOSAT soundings which detected urban/rural XCO2differences in megacities (Kort et al., 2012), the OCO-2 swath geometry opens up the path to future capabilities enabling urban characterization of greenhouse gases using hundreds of soundings over a city at each satellite overpass. California Institute of Technology

Discretizing singular point sources in hyperbolic wave propagation problems

DOE PAGES

Petersson, N. Anders; O'Reilly, Ossian; Sjogreen, Bjorn; ...

2016-06-01

Here, we develop high order accurate source discretizations for hyperbolic wave propagation problems in first order formulation that are discretized by finite difference schemes. By studying the Fourier series expansions of the source discretization and the finite difference operator, we derive sufficient conditions for achieving design accuracy in the numerical solution. Only half of the conditions in Fourier space can be satisfied through moment conditions on the source discretization, and we develop smoothness conditions for satisfying the remaining accuracy conditions. The resulting source discretization has compact support in physical space, and is spread over as many grid points as themore » number of moment and smoothness conditions. In numerical experiments we demonstrate high order of accuracy in the numerical solution of the 1-D advection equation (both in the interior and near a boundary), the 3-D elastic wave equation, and the 3-D linearized Euler equations.« less

Determining the Intensity of a Point-Like Source Observed on the Background of AN Extended Source

NASA Astrophysics Data System (ADS)

Kornienko, Y. V.; Skuratovskiy, S. I.

2014-12-01

The problem of determining the time dependence of intensity of a point-like source in case of atmospheric blur is formulated and solved by using the Bayesian statistical approach. A pointlike source is supposed to be observed on the background of an extended source with constant in time though unknown brightness. The equation system for optimal statistical estimation of the sequence of intensity values in observation moments is obtained. The problem is particularly relevant for studying gravitational mirages which appear while observing a quasar through the gravitational field of a far galaxy.

Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States

USGS Publications Warehouse

Puckett, Larry J.

1994-01-01

Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land use, population, and physiography. Fertilizer sources of nitrogen are proportionally greater in agricultural areas of the West and the Midwest than in other parts of the Nation. Animal manure contributes large proportions of nitrogen in the South and parts of the Northeast. Atmospheric deposition of nitrogen is generally greatest in areas of greatest precipitation, such as the Northeast. Point sources (sewage and industrial) generally are predominant in watersheds near cities, where they may account for large proportions of the nitrogen in streams. The transport of nitrogen in streams increases as amounts of precipitation and runoff increase and is greatest in the Northeastern United States. Because no single nonpoint nitrogen source is dominant everywhere, approaches to control nitrogen must vary throughout the Nation. Watershed-based approaches to understanding nonpoint and point sources of contamination, as used by the National Water-Quality Assessment Program, will aid water-quality and environmental managers to devise methods to reduce nitrogen pollution.

Single Crystal Diamond Needle as Point Electron Source.

PubMed

Kleshch, Victor I; Purcell, Stephen T; Obraztsov, Alexander N

2016-10-12

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

Single Crystal Diamond Needle as Point Electron Source

PubMed Central

Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

2016-01-01

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2–0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics. PMID:27731379

Single Crystal Diamond Needle as Point Electron Source

NASA Astrophysics Data System (ADS)

Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

2016-10-01

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

Petroleum hydrocarbons in a water-sediment system from Yellow River estuary and adjacent coastal area, China: Distribution pattern, risk assessment and sources.

PubMed

Wang, Min; Wang, Chuanyuan; Li, Yuanwei

2017-09-15

Aliphatic hydrocarbons (AHs), biomarker and polycyclic aromatic hydrocarbons (PAHs) concentrations of surface water and sediment samples collected from Yellow River Estuary and adjacent coastal area in China were measured to determine their spatial distributions, analyze their sources and evaluate the ecological risk of PAHs in the water-sediment system. The spatial distributions of n-alkane in sediments are mainly controlled by the mixing inputs of terrigenous and marine components. In comparison with AHs, the total concentrations of Σ16PAHs in surface sediments from a transect of the offshore area were noticeably higher than that of the riverine and estuary areas. Additionally, the AHs and total PAHs concentrations all indicated an overall pattern of a seaward decrease. The PAHs concentrations during the dry season (mainly in the form of dissolved phase) were higher than that of PAHs (mainly dissolved phase and particulate phase form) in the flooding season. In comparison with global concentration levels of PAHs, the level of PAHs in suspended particulate matter and sediments from the Yellow River Estuary was lower than those from other countries, while the concentration of PAHs in the dissolved phase were in the middle range. Petroleum contamination, mainly from oil exploration and discharge of pollutants from rivers, was the main source of n-alkanes. The PAHs in the river were mostly of petrogenic origin, while those in the estuarial and marine areas originated mainly from pyrogenic sources. The results of the toxicology assessment suggested that the PAHs in sediments from Yellow River Estuary and adjacent coastal area exhibited a low potential eco-toxicological contamination level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clay-mineral suites, sources, and inferred dispersal routes: Southern California continental shelf

USGS Publications Warehouse

Hein, J.R.; Dowling, J.S.; Schuetze, A.; Lee, H.J.

2003-01-01

Clay mineralogy is useful in determining the distribution, sources, and dispersal routes of fine-grained sediments. In addition, clay minerals, especially smectite, may control the degree to which contaminants are adsorbed by the sediment. We analyzed 250 shelf sediment samples, 24 river-suspended-sediment samples, and 12 river-bed samples for clay-mineral contents in the Southern California Borderland from Point Conception to the Mexico border. In addition, six samples were analyzed from the Palos Verdes Headland in order to characterize the clay minerals contributed to the offshore from that point source. The <2 ??m-size fraction was isolated, Mg-saturated, and glycolated before analysis by X-ray diffraction. Semi-quantitative percentages of smectite, illite, and kaolinite plus chlorite were calculated using peak areas and standard weighting factors. Most fine-grained sediment is supplied to the shelf by rivers during major winter storms, especially during El Nin??o years. The largest sediment fluxes to the region are from the Santa Ynez and Santa Clara Rivers, which drain the Transverse Ranges. The mean clay-mineral suite for the entire shelf sediment data set (26% smectite, 50% illite, 24% kaolinite+chlorite) is closely comparable to that for the mean of all the rivers (31% smectite, 49% illite, 20% kaolinite+chlorite), indicating that the main source of shelf fine-grained sediments is the adjacent rivers. However, regional variations do exist and the shelf is divided into four provinces with characteristic clay-mineral suites. The means of the clay-mineral suites of the two southernmost provinces are within analytical error of the mineral suites of adjacent rivers. The next province to the north includes Santa Monica Bay and has a suite of clay minerals derived from mixing of fine-grained sediments from several sources, both from the north and south. The northernmost province clay-mineral suite matches moderately well that of the adjacent rivers, but does

Sound source localization on an axial fan at different operating points

NASA Astrophysics Data System (ADS)

Zenger, Florian J.; Herold, Gert; Becker, Stefan; Sarradj, Ennes

2016-08-01

A generic fan with unskewed fan blades is investigated using a microphone array method. The relative motion of the fan with respect to the stationary microphone array is compensated by interpolating the microphone data to a virtual rotating array with the same rotational speed as the fan. Hence, beamforming algorithms with deconvolution, in this case CLEAN-SC, could be applied. Sound maps and integrated spectra of sub-components are evaluated for five operating points. At selected frequency bands, the presented method yields sound maps featuring a clear circular source pattern corresponding to the nine fan blades. Depending on the adjusted operating point, sound sources are located on the leading or trailing edges of the fan blades. Integrated spectra show that in most cases leading edge noise is dominant for the low-frequency part and trailing edge noise for the high-frequency part. The shift from leading to trailing edge noise is strongly dependent on the operating point and frequency range considered.

Electron transfer in silicon-bridged adjacent chromophores: the source for blue-green emission.

PubMed

Bayda, Malgorzata; Angulo, Gonzalo; Hug, Gordon L; Ludwiczak, Monika; Karolczak, Jerzy; Koput, Jacek; Dobkowski, Jacek; Marciniak, Bronislaw

2017-05-10

Si-Bridged chromophores have been proposed as sources for blue-green emission in several technological applications. The origin of this dual emission is to be found in an internal charge transfer reaction. The current work is an attempt to describe the details of these processes in these kinds of substances, and to design a molecular architecture to improve their performance. Nuclear motions essential for intramolecular charge transfer (ICT) can involve processes from twisted internal moieties to dielectric relaxation of the solvent. To address these issues, we studied ICT between adjacent chromophores in a molecular compound containing N-isopropylcarbazole (CBL) and 1,4-divinylbenzene (DVB) linked by a dimethylsilylene bridge. In nonpolar solvents emission arises from the local excited state (LE) of carbazole whereas in solvents of higher polarity dual emission was detected (LE + ICT). The CT character of the additional emission band was concluded from the linear dependence of the fluorescence maxima on solvent polarity. Electron transfer from CBL to DVB resulted in a large excited-state dipole moment (37.3 D) as determined from a solvatochromic plot and DFT calculations. Steady-state and picosecond time-resolved fluorescence experiments in butyronitrile (293-173 K) showed that the ICT excited state arises from the LE state of carbazole. These results were analyzed and found to be in accordance with an adiabatic version of Marcus theory including solvent relaxation.

KM3NeT/ARCA sensitivity to point-like neutrino sources

NASA Astrophysics Data System (ADS)

Trovato, A.; KM3NeT Collaboration

2017-09-01

KM3NeT is network of deep-sea neutrino telescopes in the Mediterranean Sea aiming at the discovery of cosmic neutrino sources (ARCA) and the determination of the neutrino mass hierarchy (ORCA). The geographical location of KM3NeT in the Northern hemisphere allows to observe most of the Galactic Plane, including the Galactic Centre. Thanks to its good angular resolution, prime targets of KM3NeT/ARCA are point-like neutrino sources and in particular galactic sources.

[Spatial heterogeneity and classified control of agricultural non-point source pollution in Huaihe River Basin].

PubMed

Zhou, Liang; Xu, Jian-Gang; Sun, Dong-Qi; Ni, Tian-Hua

2013-02-01

Agricultural non-point source pollution is of importance in river deterioration. Thus identifying and concentrated controlling the key source-areas are the most effective approaches for non-point source pollution control. This study adopts inventory method to analysis four kinds of pollution sources and their emissions intensity of the chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in 173 counties (cities, districts) in Huaihe River Basin. The four pollution sources include livestock breeding, rural life, farmland cultivation, aquacultures. The paper mainly addresses identification of non-point polluted sensitivity areas, key pollution sources and its spatial distribution characteristics through cluster, sensitivity evaluation and spatial analysis. A geographic information system (GIS) and SPSS were used to carry out this study. The results show that: the COD, TN and TP emissions of agricultural non-point sources were 206.74 x 10(4) t, 66.49 x 10(4) t, 8.74 x 10(4) t separately in Huaihe River Basin in 2009; the emission intensity were 7.69, 2.47, 0.32 t.hm-2; the proportions of COD, TN, TP emissions were 73%, 24%, 3%. The paper achieves that: the major pollution source of COD, TN and TP was livestock breeding and rural life; the sensitivity areas and priority pollution control areas among the river basin of non-point source pollution are some sub-basins of the upper branches in Huaihe River, such as Shahe River, Yinghe River, Beiru River, Jialu River and Qingyi River; livestock breeding is the key pollution source in the priority pollution control areas. Finally, the paper concludes that pollution type of rural life has the highest pollution contribution rate, while comprehensive pollution is one type which is hard to control.

Radial Distribution of X-Ray Point Sources Near the Galactic Center

NASA Astrophysics Data System (ADS)

Hong, Jae Sub; van den Berg, Maureen; Grindlay, Jonathan E.; Laycock, Silas

2009-11-01

We present the log N-log S and spatial distributions of X-ray point sources in seven Galactic bulge (GB) fields within 4° from the Galactic center (GC). We compare the properties of 1159 X-ray point sources discovered in our deep (100 ks) Chandra observations of three low extinction Window fields near the GC with the X-ray sources in the other GB fields centered around Sgr B2, Sgr C, the Arches Cluster, and Sgr A* using Chandra archival data. To reduce the systematic errors induced by the uncertain X-ray spectra of the sources coupled with field-and-distance-dependent extinction, we classify the X-ray sources using quantile analysis and estimate their fluxes accordingly. The result indicates that the GB X-ray population is highly concentrated at the center, more heavily than the stellar distribution models. It extends out to more than 1fdg4 from the GC, and the projected density follows an empirical radial relation inversely proportional to the offset from the GC. We also compare the total X-ray and infrared surface brightness using the Chandra and Spitzer observations of the regions. The radial distribution of the total infrared surface brightness from the 3.6 band μm images appears to resemble the radial distribution of the X-ray point sources better than that predicted by the stellar distribution models. Assuming a simple power-law model for the X-ray spectra, the closer to the GC the intrinsically harder the X-ray spectra appear, but adding an iron emission line at 6.7 keV in the model allows the spectra of the GB X-ray sources to be largely consistent across the region. This implies that the majority of these GB X-ray sources can be of the same or similar type. Their X-ray luminosity and spectral properties support the idea that the most likely candidate is magnetic cataclysmic variables (CVs), primarily intermediate polars (IPs). Their observed number density is also consistent with the majority being IPs, provided the relative CV to star density in the GB

MODELING PHOTOCHEMISTRY AND AEROSOL FORMATION IN POINT SOURCE PLUMES WITH THE CMAQ PLUME-IN-GRID

EPA Science Inventory

Emissions of nitrogen oxides and sulfur oxides from the tall stacks of major point sources are important precursors of a variety of photochemical oxidants and secondary aerosol species. Plumes released from point sources exhibit rather limited dimensions and their growth is gradu...

NITROGEN CONCENTRATIONS IN LOADING SOURCES FOR THREE COASTAL LAGOONS FROM ATMOSPHERIC AND WATERSHED SOURCES, ADJACENT COASTAL MARSHES, TIDAL EXCHANGES

EPA Science Inventory

Abstract and Oral Presentation Gulf Estuarine Research Society.

Standing stocks and inputs of total dissolved nitrogen (TDN) to three coastal lagoons, hereafter referred to as Kee's Bayou, Gongora, and State Park, with varying adjacent land-use, geomorphology, and water re...

Strategies for satellite-based monitoring of CO2 from distributed area and point sources

NASA Astrophysics Data System (ADS)

Schwandner, Florian M.; Miller, Charles E.; Duren, Riley M.; Natraj, Vijay; Eldering, Annmarie; Gunson, Michael R.; Crisp, David

2014-05-01

Atmospheric CO2 budgets are controlled by the strengths, as well as the spatial and temporal variabilities of CO2 sources and sinks. Natural CO2 sources and sinks are dominated by the vast areas of the oceans and the terrestrial biosphere. In contrast, anthropogenic and geogenic CO2 sources are dominated by distributed area and point sources, which may constitute as much as 70% of anthropogenic (e.g., Duren & Miller, 2012), and over 80% of geogenic emissions (Burton et al., 2013). Comprehensive assessments of CO2 budgets necessitate robust and highly accurate satellite remote sensing strategies that address the competing and often conflicting requirements for sampling over disparate space and time scales. Spatial variability: The spatial distribution of anthropogenic sources is dominated by patterns of production, storage, transport and use. In contrast, geogenic variability is almost entirely controlled by endogenic geological processes, except where surface gas permeability is modulated by soil moisture. Satellite remote sensing solutions will thus have to vary greatly in spatial coverage and resolution to address distributed area sources and point sources alike. Temporal variability: While biogenic sources are dominated by diurnal and seasonal patterns, anthropogenic sources fluctuate over a greater variety of time scales from diurnal, weekly and seasonal cycles, driven by both economic and climatic factors. Geogenic sources typically vary in time scales of days to months (geogenic sources sensu stricto are not fossil fuels but volcanoes, hydrothermal and metamorphic sources). Current ground-based monitoring networks for anthropogenic and geogenic sources record data on minute- to weekly temporal scales. Satellite remote sensing solutions would have to capture temporal variability through revisit frequency or point-and-stare strategies. Space-based remote sensing offers the potential of global coverage by a single sensor. However, no single combination of orbit

Compliance With Point-of-Sale Tobacco Control Policies in School-Adjacent Neighborhoods in Mumbai, India.

PubMed

Mistry, Ritesh; Pimple, Sharmila; Mishra, Gauravi; Gupta, Prakash C; Pednekar, Mangesh; Ranz-Schleifer, Naomi; Shastri, Surendra

2015-09-21

Purpose . We assessed factors associated with tobacco vendor compliance with India's Cigarettes and Other Tobacco Products Act (COTPA) provisions regulating tobacco sales and point-of-sale (POS) environments. Design . Study design was a cross-sectional random sample of tobacco vendors in Mumbai, India (2010). Setting . School-adjacent neighborhoods were the study setting. Subjects . Study subjects were tobacco vendors (n = 436). Measures . Face-to-face interviews, and audits of POS environments were used to assess compliance. Analysis . Factors associated with compliance were identified using logistic regression. Results . About 4% of vendors were fully compliant. Although 80% reported compliance with the ban on tobacco sales to minors, only 10% displayed signage about the ban. About 84% were compliant with the two-tobacco advertisement limit; of those displaying advertisements, 67% were compliant with size limits, 68% with content restrictions, and 8% with health warning requirements. Knowledge about fines for noncompliance was associated with compliance with the ban on sales to minors (odds ratio [OR], 2.12; 95% confidence interval [CI], 1.26, 3.56) and signage requirement (OR, 4.42; 95% CI, 1.76, 11.13). Greater compliance with the two-advertisement limit was associated with higher store income from tobacco (OR, .26; 95% CI, .09, .73) and lower neighborhood socioeconomic status (p < .01); the latter was associated with advertisement size limits compliance (p < .05). Conclusions . Compliance with COTPA provisions was low. Interventions modifying vendor knowledge about provisions and fines may increase compliance, and they should target stores that are reliant on tobacco sales.

PSFGAN: a generative adversarial network system for separating quasar point sources and host galaxy light

NASA Astrophysics Data System (ADS)

Stark, Dominic; Launet, Barthelemy; Schawinski, Kevin; Zhang, Ce; Koss, Michael; Turp, M. Dennis; Sartori, Lia F.; Zhang, Hantian; Chen, Yiru; Weigel, Anna K.

2018-06-01

The study of unobscured active galactic nuclei (AGN) and quasars depends on the reliable decomposition of the light from the AGN point source and the extended host galaxy light. The problem is typically approached using parametric fitting routines using separate models for the host galaxy and the point spread function (PSF). We present a new approach using a Generative Adversarial Network (GAN) trained on galaxy images. We test the method using Sloan Digital Sky Survey r-band images with artificial AGN point sources added that are then removed using the GAN and with parametric methods using GALFIT. When the AGN point source is more than twice as bright as the host galaxy, we find that our method, PSFGAN, can recover point source and host galaxy magnitudes with smaller systematic error and a lower average scatter (49 per cent). PSFGAN is more tolerant to poor knowledge of the PSF than parametric methods. Our tests show that PSFGAN is robust against a broadening in the PSF width of ± 50 per cent if it is trained on multiple PSFs. We demonstrate that while a matched training set does improve performance, we can still subtract point sources using a PSFGAN trained on non-astronomical images. While initial training is computationally expensive, evaluating PSFGAN on data is more than 40 times faster than GALFIT fitting two components. Finally, PSFGAN is more robust and easy to use than parametric methods as it requires no input parameters.

Is a wind turbine a point source? (L).

PubMed

Makarewicz, Rufin

2011-02-01

Measurements show that practically all noise of wind turbine noise is produced by turbine blades, sometimes a few tens of meters long, despite that the model of a point source located at the hub height is commonly used. The plane of rotating blades is the critical location of the receiver because the distances to the blades are the shortest. It is shown that such location requires certain condition to be met. The model is valid far away from the wind turbine as well.

Point source sulphur dioxide peaks and hospital presentations for asthma.

PubMed

Donoghue, A M; Thomas, M

1999-04-01

To examine the effect on hospital presentations for asthma of brief exposures to sulphur dioxide (SO2) (within the range 0-8700 micrograms/m3) emanating from two point sources in a remote rural city of 25,000 people. A time series analysis of SO2 concentrations and hospital presentations for asthma was undertaken at Mount Isa where SO2 is released into the atmosphere by a copper smelter and a lead smelter. The study examined 5 minute block mean SO2 concentrations and daily hospital presentations for asthma, wheeze, or shortness of breath. Generalised linear models and generalised additive models based on a Poisson distribution were applied. There was no evidence of any positive relation between peak SO2 concentrations and hospital presentations or admissions for asthma, wheeze, or shortness of breath. Brief exposures to high concentrations of SO2 emanating from point sources at Mount Isa do not cause sufficiently serious symptoms in asthmatic people to require presentation to hospital.

Evaluation of selective vs. point-source perforating for hydraulic fracturing

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

Underwood, P.J.; Kerley, L.

1996-12-31

This paper is a case history comparing and evaluating the effects of fracturing the Reef Ridge Diatomite formation in the Midway-Sunset Field, Kern County, California, using {open_quotes}select-fire{close_quotes} and {open_quotes}point-source{close_quotes} perforating completions. A description of the reservoir, production history, and fracturing techniques used leading up to this study is presented. Fracturing treatment analysis and production history matching were used to evaluate the reservoir and fracturing parameters for both completion types. The work showed that single fractures were created with the point-source (PS) completions, and multiple fractures resulted from many of the select-fire (SF) completions. A good correlation was developed between productivitymore » and the product of formation permeability, net fracture height, bottomhole pressure, and propped fracture length. Results supported the continued development of 10 wells using the PS concept with a more efficient treatment design, resulting in substantial cost savings.« less

Double point source W-phase inversion: Real-time implementation and automated model selection

USGS Publications Warehouse

Nealy, Jennifer; Hayes, Gavin

2015-01-01

Rapid and accurate characterization of an earthquake source is an extremely important and ever evolving field of research. Within this field, source inversion of the W-phase has recently been shown to be an effective technique, which can be efficiently implemented in real-time. An extension to the W-phase source inversion is presented in which two point sources are derived to better characterize complex earthquakes. A single source inversion followed by a double point source inversion with centroid locations fixed at the single source solution location can be efficiently run as part of earthquake monitoring network operational procedures. In order to determine the most appropriate solution, i.e., whether an earthquake is most appropriately described by a single source or a double source, an Akaike information criterion (AIC) test is performed. Analyses of all earthquakes of magnitude 7.5 and greater occurring since January 2000 were performed with extended analyses of the September 29, 2009 magnitude 8.1 Samoa earthquake and the April 19, 2014 magnitude 7.5 Papua New Guinea earthquake. The AIC test is shown to be able to accurately select the most appropriate model and the selected W-phase inversion is shown to yield reliable solutions that match published analyses of the same events.

Floating-point scaling technique for sources separation automatic gain control

NASA Astrophysics Data System (ADS)

Fermas, A.; Belouchrani, A.; Ait-Mohamed, O.

2012-07-01

Based on the floating-point representation and taking advantage of scaling factor indetermination in blind source separation (BSS) processing, we propose a scaling technique applied to the separation matrix, to avoid the saturation or the weakness in the recovered source signals. This technique performs an automatic gain control in an on-line BSS environment. We demonstrate the effectiveness of this technique by using the implementation of a division-free BSS algorithm with two inputs, two outputs. The proposed technique is computationally cheaper and efficient for a hardware implementation compared to the Euclidean normalisation.

Stochastic point-source modeling of ground motions in the Cascadia region

USGS Publications Warehouse

Atkinson, G.M.; Boore, D.M.

1997-01-01

A stochastic model is used to develop preliminary ground motion relations for the Cascadia region for rock sites. The model parameters are derived from empirical analyses of seismographic data from the Cascadia region. The model is based on a Brune point-source characterized by a stress parameter of 50 bars. The model predictions are compared to ground-motion data from the Cascadia region and to data from large earthquakes in other subduction zones. The point-source simulations match the observations from moderate events (M 100 km). The discrepancy at large magnitudes suggests further work on modeling finite-fault effects and regional attenuation is warranted. In the meantime, the preliminary equations are satisfactory for predicting motions from events of M < 7 and provide conservative estimates of motions from larger events at distances less than 100 km.

Temperature Effects of Point Sources, Riparian Shading, and Dam Operations on the Willamette River, Oregon

USGS Publications Warehouse

Rounds, Stewart A.

2007-01-01

Water temperature is an important factor influencing the migration, rearing, and spawning of several important fish species in rivers of the Pacific Northwest. To protect these fish populations and to fulfill its responsibilities under the Federal Clean Water Act, the Oregon Department of Environmental Quality set a water temperature Total Maximum Daily Load (TMDL) in 2006 for the Willamette River and the lower reaches of its largest tributaries in northwestern Oregon. As a result, the thermal discharges of the largest point sources of heat to the Willamette River now are limited at certain times of the year, riparian vegetation has been targeted for restoration, and upstream dams are recognized as important influences on downstream temperatures. Many of the prescribed point-source heat-load allocations are sufficiently restrictive that management agencies may need to expend considerable resources to meet those allocations. Trading heat allocations among point-source dischargers may be a more economical and efficient means of meeting the cumulative point-source temperature limits set by the TMDL. The cumulative nature of these limits, however, precludes simple one-to-one trades of heat from one point source to another; a more detailed spatial analysis is needed. In this investigation, the flow and temperature models that formed the basis of the Willamette temperature TMDL were used to determine a spatially indexed 'heating signature' for each of the modeled point sources, and those signatures then were combined into a user-friendly, spreadsheet-based screening tool. The Willamette River Point-Source Heat-Trading Tool allows the user to increase or decrease the heating signature of each source and thereby evaluate the effects of a wide range of potential point-source heat trades. The predictions of the Trading Tool were verified by running the Willamette flow and temperature models under four different trading scenarios, and the predictions typically were accurate

Systematic Review: Impact of point sources on antibiotic-resistant bacteria in the natural environment.

PubMed

Bueno, I; Williams-Nguyen, J; Hwang, H; Sargeant, J M; Nault, A J; Singer, R S

2018-02-01

Point sources such as wastewater treatment plants and agricultural facilities may have a role in the dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG). To analyse the evidence for increases in ARB in the natural environment associated with these point sources of ARB and ARG, we conducted a systematic review. We evaluated 5,247 records retrieved through database searches, including both studies that ascertained ARG and ARB outcomes. All studies were subjected to a screening process to assess relevance to the question and methodology to address our review question. A risk of bias assessment was conducted upon the final pool of studies included in the review. This article summarizes the evidence only for those studies with ARB outcomes (n = 47). Thirty-five studies were at high (n = 11) or at unclear (n = 24) risk of bias in the estimation of source effects due to lack of information and/or failure to control for confounders. Statistical analysis was used in ten studies, of which one assessed the effect of multiple sources using modelling approaches; none reported effect measures. Most studies reported higher ARB prevalence or concentration downstream/near the source. However, this evidence was primarily descriptive and it could not be concluded that there is a clear impact of point sources on increases in ARB in the environment. To quantify increases in ARB in the environment due to specific point sources, there is a need for studies that stress study design, control of biases and analytical tools to provide effect measure estimates. © 2017 Blackwell Verlag GmbH.

Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly accomplished by cold biasing the reservoir and using electrical heaters to provide the required control power. Using this method, the loop operating temperature can be controlled within +/- 0.5K. However, because of the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP has been carried out to investigate the effects on the LHP operation when the control temperature sensor is placed on the heat source instead of the reservoir. In these tests, the LHP reservoir is cold-biased and is heated by a control heater. Tests results show that it is feasible to use the heat source temperature for feedback control of the LHP operation. Using this method, the heat source temperature can be maintained within a tight range for moderate and high powers. At low powers, however, temperature oscillations may occur due to interactions among the reservoir control heater power, the heat source mass, and the heat output from the heat source. In addition, the heat source temperature could temporarily deviate from its set point during fast thermal transients. The implication is that more sophisticated feedback control algorithms need to be implemented for LHP transient operation when the heat source temperature is used for feedback control.

An Exact Algebraic Evaluation of Path-Length Difference for Two-Source Interference

ERIC Educational Resources Information Center

Hopper, Seth; Howell, John

2006-01-01

When studying wave interference, one often wants to know the difference in path length for two waves arriving at a common point P but coming from adjacent sources. For example, in many contexts interference maxima occur where this path-length difference is an integer multiple of the wavelength. The standard approximation for the path-length…

Study on Huizhou architecture of point cloud registration based on optimized ICP algorithm

NASA Astrophysics Data System (ADS)

Zhang, Runmei; Wu, Yulu; Zhang, Guangbin; Zhou, Wei; Tao, Yuqian

2018-03-01

In view of the current point cloud registration software has high hardware requirements, heavy workload and moltiple interactive definition, the source of software with better processing effect is not open, a two--step registration method based on normal vector distribution feature and coarse feature based iterative closest point (ICP) algorithm is proposed in this paper. This method combines fast point feature histogram (FPFH) algorithm, define the adjacency region of point cloud and the calculation model of the distribution of normal vectors, setting up the local coordinate system for each key point, and obtaining the transformation matrix to finish rough registration, the rough registration results of two stations are accurately registered by using the ICP algorithm. Experimental results show that, compared with the traditional ICP algorithm, the method used in this paper has obvious time and precision advantages for large amount of point clouds.

Lessons Learned from OMI Observations of Point Source SO2 Pollution

NASA Technical Reports Server (NTRS)

Krotkov, N.; Fioletov, V.; McLinden, Chris

2011-01-01

The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. Although anthropogenic SO2 signals may not be detectable in a single OMI pixel, it is possible to see the source and determine its exact location by averaging a large number of individual measurements. We describe new techniques for spatial and temporal averaging that have been applied to the OMI SO2 data to determine the spatial distributions or "fingerprints" of SO2 burdens from top 100 pollution sources in North America. The technique requires averaging of several years of OMI daily measurements to observe SO2 pollution from typical anthropogenic sources. We found that the largest point sources of SO2 in the U.S. produce elevated SO2 values over a relatively small area - within 20-30 km radius. Therefore, one needs higher than OMI spatial resolution to monitor typical SO2 sources. TROPOMI instrument on the ESA Sentinel 5 precursor mission will have improved ground resolution (approximately 7 km at nadir), but is limited to once a day measurement. A pointable geostationary UVB spectrometer with variable spatial resolution and flexible sampling frequency could potentially achieve the goal of daily monitoring of SO2 point sources and resolve downwind plumes. This concept of taking the measurements at high frequency to enhance weak signals needs to be demonstrated with a GEOCAPE precursor mission before 2020, which will help formulating GEOCAPE measurement requirements.

The gamma ray continuum spectrum from the galactic center disk and point sources

NASA Technical Reports Server (NTRS)

Gehrels, Neil; Tueller, Jack

1992-01-01

A light curve of gamma-ray continuum emission from point sources in the galactic center region is generated from balloon and satellite observations made over the past 25 years. The emphasis is on the wide field-of-view instruments which measure the combined flux from all sources within approximately 20 degrees of the center. These data have not been previously used for point-source analyses because of the unknown contribution from diffuse disk emission. In this study, the galactic disk component is estimated from observations made by the Gamma Ray Imaging Spectrometer (GRIS) instrument in Oct. 1988. Surprisingly, there are several times during the past 25 years when all gamma-ray sources (at 100 keV) within about 20 degrees of the galactic center are turned off or are in low emission states. This implies that the sources are all variable and few in number. The continuum gamma-ray emission below approximately 150 keV from the black hole candidate 1E1740.7-2942 is seen to turn off in May 1989 on a time scale of less than two weeks, significantly shorter than ever seen before. With the continuum below 150 keV turned off, the spectral shape derived from the HEXAGONE observation on 22 May 1989 is very peculiar with a peak near 200 keV. This source was probably in its normal state for more than half of all observations since the mid-1960's. There are only two observations (in 1977 and 1979) for which the sum flux from the point sources in the region significantly exceeds that from 1E1740.7-2942 in its normal state.

Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution.

PubMed

Fujioka, R S

2001-01-01

The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely

Overview of on-farm bioremediation systems to reduce the occurrence of point source contamination.

PubMed

De Wilde, Tineke; Spanoghe, Pieter; Debaer, Christof; Ryckeboer, Jaak; Springael, Dirk; Jaeken, Peter

2007-02-01

Contamination of ground and surface water puts pressure on the use of pesticides. Pesticide contamination of water can often be linked to point sources rather than to diffuse sources. Examples of such point sources are areas on farms where pesticides are handled and filled into sprayers, and where sprayers are cleaned. To reduce contamination from these point sources, different kinds of bioremediation system are being researched in various member states of the EU. Bioremediation is the use of living organisms, primarily microorganisms, to degrade the environmental contaminants into less toxic forms. The systems available for biocleaning of pesticides vary according to their shape and design. Up till now, three systems have been extensively described and reported: the biobed, the Phytobac and the biofilter. Most of these constructions are excavations or different sizes of container filled with biological material. Typical overall clean-up efficiency exceeds 95%, realising even more than 99% in many cases. This paper provides an overview of the state of the art of these bioremediation systems and discusses their construction, efficiency and drawbacks.

Occurrence and source apportionment of sulfonamides and their metabolites in Liaodong Bay and the adjacent Liao River basin, North China.

PubMed

Jia, Ai; Hu, Jianying; Wu, Xiaoqin; Peng, Hui; Wu, Shimin; Dong, Zhaomin

2011-06-01

The presence of antibiotics in the environment is of great concern because of their potential for resistance selection among pathogens. In the present study we investigated the occurrence of 19 sulfonamides, five N-acetylated sulfonamide metabolites, and trimethoprim in the Liao River basin and adjacent Liaodong Bay, China, as well as 10 human/agricultural source samples. Within the 35 river samples, 12 sulfonamides, four acetylated sulfonamides, and trimethoprim were detected, with the dominant being sulfamethoxazole (66.6 ng/L), N-acetylsulfamethoxazole (63.1 ng/L), trimethoprim (29.0 ng/L), sulfadiazine (14.0 ng/L), and sulfamonomethoxine (8.4 ng/L); within the 36 marine samples, 10 chemicals were detected, with the main contributions from sulfamethoxazole (25.2 ng/L) and N-acetylsulfamethoxazole (28.6 ng/L). Sulfamethoxazole (25.9%), N-acetylsulfamethoxazole (46.6%), trimethoprim (22.9%), and sulfapyridine (1.4%) were the main chemicals from human sources, while sulfamonomethoxine, sulfamethazine, sulfaquinoxaline, sulfaguanidine, sulfadiazine, sulfanilamide, and sulfamethoxypyridazine were dominant in the animal husbandry sources, specifically, swine and poultry farms, and sulfamethoxazole (91%) was dominant in the mariculture source. A principal component analysis with multiple linear regression was performed to evaluate the source apportionment of total sulfonamides in Liaodong Bay. It was found that animal husbandry contributed 15.2% of total sulfonamides, while human sources contributed 28.5%, and combined human and mariculture sources contributed 56.3%. In addition, the mariculture contribution was 24.1% of total sulfonamides into the sea based on mass flux estimation. The present study is the first report that the environmental levels of sulfonamide metabolites were comparable to the corresponding parents; therefore, we should pay attention to their environmental occurrence. Source apportionment showed human discharge (60.7%) significantly

Microbial Source Tracking in Adjacent Karst Springs.

PubMed

Ohad, Shoshanit; Vaizel-Ohayon, Dalit; Rom, Meir; Guttman, Joseph; Berger, Diego; Kravitz, Valeria; Pilo, Shlomo; Huberman, Zohar; Kashi, Yechezkel; Rorman, Efrat

2015-08-01

Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

All flavour point-source search with the ANTARES neutrino telescope

NASA Astrophysics Data System (ADS)

Michael, Tino

2017-09-01

ANTARES is the largest neutrino telescope in the Northern Hemisphere. The detector has established excellent pointing resolution for muon neutrinos (0.4 degrees) and a degree-level resolution also for contained shower events (about 2 degrees). Together with its geographical location, the good angular resolution makes ANTARES an excellent tool to test for the presence of cosmic sources in the Southern Hemisphere and in particular the area around the Galactic Centre, where IceCube reports a number of high-energy events. In this contribution, we present a search for cosmic neutrino sources using ANTARES data taken from early 2007 until the end of 2013. Such sources are identified as a cluster of events in the combined track and shower channels. In addition to the all-flavour full-sky and candidate list searches, we focus on a restricted region around the Galactic Centre. Different spectral indices for the neutrino energy spectrum have been investigated as well as possible extended sources.

HYDROLOGY AND SEDIMENT MODELING USING THE BASINS NON-POINT SOURCE MODEL

EPA Science Inventory

The Non-Point Source Model (Hydrologic Simulation Program-Fortran, or HSPF) within the EPA Office of Water's BASINS watershed modeling system was used to simulate streamflow and total suspended solids within Contentnea Creek, North Carolina, which is a tributary of the Neuse Rive...

Analytical close-to-source investigation for an isotropic point source in an unbounded, anisotropically scattering medium

NASA Astrophysics Data System (ADS)

Rinzema, Kees; ten Bosch, Jaap J.; Ferwerda, Hedzer A.; Hoenders, Bernhard J.

1995-01-01

The diffusion approximation, which is often used to describe the propagation of light in biological tissues, is only good at a sufficient distance from sources and boundaries. Light- tissue interaction is however most intense in the region close to the source. It would therefore be interesting to study this region more closely. Although scattering in biological tissues is predominantly forward peaked, explicit solutions to the transport equation have only been obtained in the case of isotropic scattering. Particularly, for the case of an isotropic point source in an unbounded, isotropically scattering medium the solution is well known. We show that this problem can also be solved analytically if the scattering is no longer isotropic, while everything else remains the same.

Nature of the Diffuse Source and Its Central Point-like Source in SNR 0509–67.5

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

Litke, Katrina C.; Chu, You-Hua; Holmes, Abigail

We examine a diffuse emission region near the center of SNR 0509−67.5 to determine its nature. Within this diffuse region we observe a point-like source that is bright in the near-IR, but is not visible in the B and V bands. We consider an emission line observed at 6766 Å and the possibilities that it is Ly α , H α , and [O ii] λ 3727. We examine the spectral energy distribution (SED) of the source, comprised of Hubble Space Telescope B , V , I , J , and H bands in addition to Spitzer /IRAC 3.6, 4.5,more » 5.8, and 8 μ m bands. The peak of the SED is consistent with a background galaxy at z ≈ 0.8 ± 0.2 and a possible Balmer jump places the galaxy at z ≈ 0.9 ± 0.3. These SED considerations support the emission line’s identification as [O ii] λ 3727. We conclude that the diffuse source in SNR 0509−67.5 is a background galaxy at z ≈ 0.82. Furthermore, we identify the point-like source superposed near the center of the galaxy as its central bulge. Finally, we find no evidence for a surviving companion star, indicating a double-degenerate origin for SNR 0509−67.5.« less

A Voronoi interior adjacency-based approach for generating a contour tree

NASA Astrophysics Data System (ADS)

Chen, Jun; Qiao, Chaofei; Zhao, Renliang

2004-05-01

A contour tree is a good graphical tool for representing the spatial relations of contour lines and has found many applications in map generalization, map annotation, terrain analysis, etc. A new approach for generating contour trees by introducing a Voronoi-based interior adjacency set concept is proposed in this paper. The immediate interior adjacency set is employed to identify all of the children contours of each contour without contour elevations. It has advantages over existing methods such as the point-in-polygon method and the region growing-based method. This new approach can be used for spatial data mining and knowledge discovering, such as the automatic extraction of terrain features and construction of multi-resolution digital elevation model.

Induction heating pure vapor source of high temperature melting point materials on electron cyclotron resonance ion source.

PubMed

Kutsumi, Osamu; Kato, Yushi; Matsui, Yuuki; Kitagawa, Atsushi; Muramatsu, Masayuki; Uchida, Takashi; Yoshida, Yoshikazu; Sato, Fuminobu; Iida, Toshiyuki

2010-02-01

Multicharged ions that are needed are produced from solid pure material with high melting point in an electron cyclotron resonance ion source. We develop an evaporator by using induction heating (IH) with multilayer induction coil, which is made from bare molybdenum or tungsten wire without water cooling and surrounding the pure vaporized material. We optimize the shapes of induction coil and vaporized materials and operation of rf power supply. We conduct experiment to investigate the reproducibility and stability in the operation and heating efficiency. IH evaporator produces pure material vapor because materials directly heated by eddy currents have no contact with insulated materials, which are usually impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10(-4)-10(-3) Pa. We measure the temperature of the vaporized materials with different shapes, and compare them with the result of modeling. We estimate the efficiency of the IH vapor source. We are aiming at the evaporator's higher melting point material than that of iron.

Active control on high-order coherence and statistic characterization on random phase fluctuation of two classical point sources.

PubMed

Hong, Peilong; Li, Liming; Liu, Jianji; Zhang, Guoquan

2016-03-29

Young's double-slit or two-beam interference is of fundamental importance to understand various interference effects, in which the stationary phase difference between two beams plays the key role in the first-order coherence. Different from the case of first-order coherence, in the high-order optical coherence the statistic behavior of the optical phase will play the key role. In this article, by employing a fundamental interfering configuration with two classical point sources, we showed that the high- order optical coherence between two classical point sources can be actively designed by controlling the statistic behavior of the relative phase difference between two point sources. Synchronous position Nth-order subwavelength interference with an effective wavelength of λ/M was demonstrated, in which λ is the wavelength of point sources and M is an integer not larger than N. Interestingly, we found that the synchronous position Nth-order interference fringe fingerprints the statistic trace of random phase fluctuation of two classical point sources, therefore, it provides an effective way to characterize the statistic properties of phase fluctuation for incoherent light sources.

New developments in ALFT's soft x-ray point sources

NASA Astrophysics Data System (ADS)

Cintron, Dario F.; Guo, Xiaoming; Xu, Meisheng; Ye, Rubin; Antoshko, Yuriy; Antoshko, Yuriy; Drew, Steve; Philippe, Albert; Panarella, Emilio

2002-07-01

The new development in ALFT soft X-ray point source VSX-400 consists mainly of an improvement of the nozzle design to reduce the source size, as well as the introduction of a novel trigger system, capable of triggering the discharge hundreds of million of times without failure, and a debris removal system. Continuous operation for 8 hours at 20 kHz allows us to achieve 400 mW of useful soft X-ray radiation around 1 nm wavelength. In another regime of operation with a high energy machine, the VSX-Z, we have been able to achieve consistently 10 J of X-rays per pulse at a repetition rate that can reach 1 Hz with an input electrical energy of approximately 3 kJ and an efficiency in excess of 10-3.

Assessing the effects of non-point source pollution on American Samoa's coral reef communities.

PubMed

Houk, Peter; Didonato, Guy; Iguel, John; Van Woesik, Robert

2005-08-01

Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels.

Quantitative identification of riverine nitrogen from point, direct runoff and base flow sources.

PubMed

Huang, Hong; Zhang, Baifa; Lu, Jun

2014-01-01

We present a methodological example for quantifying the contributions of riverine total nitrogen (TN) from point, direct runoff and base flow sources by combining a recursive digital filter technique and statistical methods. First, we separated daily riverine flow into direct runoff and base flow using a recursive digital filter technique; then, a statistical model was established using daily simultaneous data for TN load, direct runoff rate, base flow rate, and temperature; and finally, the TN loading from direct runoff and base flow sources could be inversely estimated. As a case study, this approach was adopted to identify the TN source contributions in Changle River, eastern China. Results showed that, during 2005-2009, the total annual TN input to the river was 1,700.4±250.2 ton, and the contributions of point, direct runoff and base flow sources were 17.8±2.8%, 45.0±3.6%, and 37.2±3.9%, respectively. The innovation of the approach is that the nitrogen from direct runoff and base flow sources could be separately quantified. The approach is simple but detailed enough to take the major factors into account, providing an effective and reliable method for riverine nitrogen loading estimation and source apportionment.

Size cues and the adjacency principle.

DOT National Transportation Integrated Search

1963-11-01

The purpose of the present study was to apply the adjacency principle to the perception of relative depth from size cues. In agreement with the adjacency principle, it was found that the size cue between adjacent objects was more effective than the s...

Reduction of point contamination sources of pesticide from a vineyard farm.

PubMed

Fait, Gabriella; Nicelli, Marco; Fragoulis, George; Trevisan, Marco; Capri, Ettore

2007-05-01

Although plant protection products are already regulated in Europe under Directive 91/414/EEC, there is increasing concern about the pollution of ground and surface water caused by point sources of pesticides, such as tank filling, spillages, faulty equipment, washing, waste disposal, and direct contamination. One tool for the reduction of pesticide point source contamination is a biological system where chemicals are bound and biologically degraded. This paper presents an offset lined system where wastewaters containing pesticide residues leach through a biomix. A pump system is provided to pump the water onto the surface of the biomix and allow it to drain under gravity, keeping the biomix wet. The analysis of residues of nine pesticides in the water, biomix, and sediment inside the tank showed the biobed to function well, with a water decontamination greater than 90%. The use of this system mitigated the potential for pollution (pesticide concentrations higher than 0.1 microg/L) of 1 km of the river system surrounding the farm.

The Unicellular State as a Point Source in a Quantum Biological System

PubMed Central

Torday, John S.; Miller, William B.

2016-01-01

A point source is the central and most important point or place for any group of cohering phenomena. Evolutionary development presumes that biological processes are sequentially linked, but neither directed from, nor centralized within, any specific biologic structure or stage. However, such an epigenomic entity exists and its transforming effects can be understood through the obligatory recapitulation of all eukaryotic lifeforms through a zygotic unicellular phase. This requisite biological conjunction can now be properly assessed as the focal point of reconciliation between biology and quantum phenomena, illustrated by deconvoluting complex physiologic traits back to their unicellular origins. PMID:27240413

A spatial model to aggregate point-source and nonpoint-source water-quality data for large areas

USGS Publications Warehouse

White, D.A.; Smith, R.A.; Price, C.V.; Alexander, R.B.; Robinson, K.W.

1992-01-01

More objective and consistent methods are needed to assess water quality for large areas. A spatial model, one that capitalizes on the topologic relationships among spatial entities, to aggregate pollution sources from upstream drainage areas is described that can be implemented on land surfaces having heterogeneous water-pollution effects. An infrastructure of stream networks and drainage basins, derived from 1:250,000-scale digital-elevation models, define the hydrologic system in this spatial model. The spatial relationships between point- and nonpoint pollution sources and measurement locations are referenced to the hydrologic infrastructure with the aid of a geographic information system. A maximum-branching algorithm has been developed to simulate the effects of distance from a pollutant source to an arbitrary downstream location, a function traditionally employed in deterministic water quality models. ?? 1992.

Sources and transport of phosphorus to rivers in California and adjacent states, U.S., as determined by SPARROW modeling

USGS Publications Warehouse

Domagalski, Joseph L.; Saleh, Dina

2015-01-01

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de-trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small- and intermediate-sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.

VizieR Online Data Catalog: First Fermi-LAT Inner Galaxy point source catalog (Ajello+, 2016)

NASA Astrophysics Data System (ADS)

Ajello, M.; Albert, A.; Atwood, W. B.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Cecchi, C.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; di Venere, L.; Drell, P. S.; Favuzzi, C.; Ferrara, E. C.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Harding, A. K.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Johannesson, G.; Johnson, A. S.; Kamae, T.; Karwin, C.; Knodlseder, J.; Kuss, M.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Malyshev, D.; Manfreda, A.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Raino, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Sanchez-Conde, M.; Parkinson, P. M. S.; Sgro, C.; Siskind, E. J.; Smith, D. A.; Spada, F.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Thayer, J. B.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Winer, B. L.; Wood, K. S.; Zaharijas, G.; Zimmer, S.

2018-01-01

The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission toward the Galactic center (GC) in high-energy γ-rays. This paper describes the analysis of data taken during the first 62 months of the mission in the energy range 1-100GeV from a 15°x15° region about the direction of the GC. Specialized interstellar emission models (IEMs) are constructed to enable the separation of the γ-ray emissions produced by cosmic ray particles interacting with the interstellar gas and radiation fields in the Milky Way into that from the inner ~1kpc surrounding the GC, and that from the rest of the Galaxy. A catalog of point sources for the 15°x15° region is self-consistently constructed using these IEMs: the First Fermi-LAT Inner Galaxy Point Source Catalog (1FIG). The spatial locations, fluxes, and spectral properties of the 1FIG sources are presented, and compared with γ-ray point sources over the same region taken from existing catalogs. After subtracting the interstellar emission and point-source contributions a residual is found. If templates that peak toward the GC are used to model the positive residual the agreement with the data improves, but none of the additional templates tried account for all of its spatial structure. The spectrum of the positive residual modeled with these templates has a strong dependence on the choice of IEM. (2 data files).

Metabolomics for in situ environmental monitoring of surface waters impacted by contaminants from both point and non-point sources

EPA Science Inventory

We investigated the efficacy of metabolomics for field-monitoring of fish exposed to waste water treatment plant (WWTP) effluents and non-point sources of chemical contamination. Lab-reared male fathead minnows (Pimephales promelas, FHM) were held in mobile monitoring units and e...

46 CFR 148.445 - Adjacent spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by natural...

46 CFR 148.445 - Adjacent spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by natural...

46 CFR 148.445 - Adjacent spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by natural...

46 CFR 148.445 - Adjacent spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by natural...

Successive Two-sided Loop Jets Caused by Magnetic Reconnection between Two Adjacent Filamentary Threads

NASA Astrophysics Data System (ADS)

Tian, Zhanjun; Liu, Yu; Shen, Yuandeng; Elmhamdi, Abouazza; Su, Jiangtao; Liu, Ying D.; Kordi, Ayman. S.

2017-08-01

We present observational analysis of two successive two-sided loop jets observed by the ground-based New Vacuum Solar Telescope and the space-borne Solar Dynamics Observatory. The two successive two-sided loop jets manifested similar evolution processes and both were associated with the interaction of two small-scale adjacent filamentary threads, magnetic emerging, and cancellation processes at the jet’s source region. High temporal and high spatial resolution observations reveal that the two adjacent ends of the two filamentary threads are rooted in opposite magnetic polarities within the source region. The two threads approached each other, and then an obvious brightening patch is observed at the interaction position. Subsequently, a pair of hot plasma ejections are observed heading in opposite directions along the paths of the two filamentary threads at a typical speed for two-sided loop jets of the order 150 km s-1. Close to the end of the second jet, we report the formation of a bright hot loop structure at the source region, which suggests the formation of new loops during the interaction. Based on the observational results, we propose that the observed two-sided loop jets are caused by magnetic reconnection between the two adjacent filamentary threads, largely different from the previous scenario that a two-sided loop jet is generated by magnetic reconnection between an emerging bipole and the overlying horizontal magnetic fields.

Method of and apparatus for generating an interstitial point in a data stream having an even number of data points

NASA Technical Reports Server (NTRS)

Edwards, T. R. (Inventor)

1985-01-01

Apparatus for doubling the data density rate of an analog to digital converter or doubling the data density storage capacity of a memory deviced is discussed. An interstitial data point midway between adjacent data points in a data stream having an even number of equal interval data points is generated by applying a set of predetermined one-dimensional convolute integer coefficients which can include a set of multiplier coefficients and a normalizer coefficient. Interpolator means apply the coefficients to the data points by weighting equally on each side of the center of the even number of equal interval data points to obtain an interstital point value at the center of the data points. A one-dimensional output data set, which is twice as dense as a one-dimensional equal interval input data set, can be generated where the output data set includes interstitial points interdigitated between adjacent data points in the input data set. The method for generating the set of interstital points is a weighted, nearest-neighbor, non-recursive, moving, smoothing averaging technique, equivalent to applying a polynomial regression calculation to the data set.

THE IMPACT OF POINT-SOURCE SUBTRACTION RESIDUALS ON 21 cm EPOCH OF REIONIZATION ESTIMATION

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

Trott, Cathryn M.; Wayth, Randall B.; Tingay, Steven J., E-mail: cathryn.trott@curtin.edu.au

Precise subtraction of foreground sources is crucial for detecting and estimating 21 cm H I signals from the Epoch of Reionization (EoR). We quantify how imperfect point-source subtraction due to limitations of the measurement data set yields structured residual signal in the data set. We use the Cramer-Rao lower bound, as a metric for quantifying the precision with which a parameter may be measured, to estimate the residual signal in a visibility data set due to imperfect point-source subtraction. We then propagate these residuals into two metrics of interest for 21 cm EoR experiments-the angular power spectrum and two-dimensional powermore » spectrum-using a combination of full analytic covariant derivation, analytic variant derivation, and covariant Monte Carlo simulations. This methodology differs from previous work in two ways: (1) it uses information theory to set the point-source position error, rather than assuming a global rms error, and (2) it describes a method for propagating the errors analytically, thereby obtaining the full correlation structure of the power spectra. The methods are applied to two upcoming low-frequency instruments that are proposing to perform statistical EoR experiments: the Murchison Widefield Array and the Precision Array for Probing the Epoch of Reionization. In addition to the actual antenna configurations, we apply the methods to minimally redundant and maximally redundant configurations. We find that for peeling sources above 1 Jy, the amplitude of the residual signal, and its variance, will be smaller than the contribution from thermal noise for the observing parameters proposed for upcoming EoR experiments, and that optimal subtraction of bright point sources will not be a limiting factor for EoR parameter estimation. We then use the formalism to provide an ab initio analytic derivation motivating the 'wedge' feature in the two-dimensional power spectrum, complementing previous discussion in the literature.« less

Apparatus and method for creating a photonic densely-accumulated ray-point

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2012-01-01

An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

Impact of changes in labor resources and transfers of land use rights on agricultural non-point source pollution in Jiangsu Province, China.

PubMed

Lu, Hua; Xie, Hualin

2018-02-01

This study systematically explores the likely mechanisms driving the effect of the transfer of agricultural land use rights (ALURs) on agricultural non-point source pollution (ANSP) in the context of changing agricultural labor resources. It quantitatively estimates the direction and degree of this influence from a microeconomic perspective using data from rural households. The results reveal that economies of scale caused by ALURs transfers contribute to reducing both the ANSP and marginal costs of inputs. Changes in agricultural labor resources lead to reductions in agricultural labor supply and negatively impact on ANSP. Encouraging farmers to participate in ALURs transfers, therefore, helps to reduce ANSP. The government and related departments should implement policies that support farmers who decide to rent an entire village's land or the adjacent land to achieve economies of scale. Accelerating the development of small farm machinery that is suitable for smaller farm plots and the elderly can serve to reduce the use of chemical fertilizer and promote green production and sustainable agricultural development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acoustic power of a moving point source in a moving medium

NASA Technical Reports Server (NTRS)

Cole, J. E., III; Sarris, I. I.

1976-01-01

The acoustic power output of a moving point-mass source in an acoustic medium which is in uniform motion and infinite in extent is examined. The acoustic medium is considered to be a homogeneous fluid having both zero viscosity and zero thermal conductivity. Two expressions for the acoustic power output are obtained based on a different definition cited in the literature for the average energy-flux vector in an acoustic medium in uniform motion. The acoustic power output of the source is found by integrating the component of acoustic intensity vector in the radial direction over the surface of an infinitely long cylinder which is within the medium and encloses the line of motion of the source. One of the power expressions is found to give unreasonable results even though the flow is uniform.

40 CFR 414.111 - Toxic pollutant standards for indirect discharge point sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Toxic pollutant standards for indirect discharge point sources. 414.111 Section 414.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Indirect...

40 CFR 414.111 - Toxic pollutant standards for indirect discharge point sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Toxic pollutant standards for indirect discharge point sources. 414.111 Section 414.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Indirect...

40 CFR 414.111 - Toxic pollutant standards for indirect discharge point sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Toxic pollutant standards for indirect discharge point sources. 414.111 Section 414.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Indirect...

40 CFR 414.111 - Toxic pollutant standards for indirect discharge point sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Toxic pollutant standards for indirect discharge point sources. 414.111 Section 414.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Indirect...

40 CFR 414.111 - Toxic pollutant standards for indirect discharge point sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Toxic pollutant standards for indirect discharge point sources. 414.111 Section 414.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Indirect...

Statistical measurement of the gamma-ray source-count distribution as a function of energy

NASA Astrophysics Data System (ADS)

Zechlin, H.-S.; Cuoco, A.; Donato, F.; Fornengo, N.; Regis, M.

2017-01-01

Photon counts statistics have recently been proven to provide a sensitive observable for characterizing gamma-ray source populations and for measuring the composition of the gamma-ray sky. In this work, we generalize the use of the standard 1-point probability distribution function (1pPDF) to decompose the high-latitude gamma-ray emission observed with Fermi-LAT into: (i) point-source contributions, (ii) the Galactic foreground contribution, and (iii) a diffuse isotropic background contribution. We analyze gamma-ray data in five adjacent energy bands between 1 and 171 GeV. We measure the source-count distribution dN/dS as a function of energy, and demonstrate that our results extend current measurements from source catalogs to the regime of so far undetected sources. Our method improves the sensitivity for resolving point-source populations by about one order of magnitude in flux. The dN/dS distribution as a function of flux is found to be compatible with a broken power law. We derive upper limits on further possible breaks as well as the angular power of unresolved sources. We discuss the composition of the gamma-ray sky and capabilities of the 1pPDF method.

The Atacama Cosmology Telescope: Development and preliminary results of point source observations

NASA Astrophysics Data System (ADS)

Fisher, Ryan P.

2009-06-01

The Atacama Cosmology Telescope (ACT) is a six meter diameter telescope designed to measure the millimeter sky with arcminute angular resolution. The instrument is currently conducting its third season of observations from Cerro Toco in the Chilean Andes. The primary science goal of the experiment is to expand our understanding of cosmology by mapping the temperature fluctuations of the Cosmic Microwave Background (CMB) at angular scales corresponding to multipoles up to [cursive l] ~ 10000. The primary receiver for current ACT observations is the Millimeter Bolometer Array Camera (MBAC). The instrument is specially designed to observe simultaneously at 148 GHz, 218 GHz and 277 GHz. To accomplish this, the camera has three separate detector arrays, each containing approximately 1000 detectors. After discussing the ACT experiment in detail, a discussion of the development and testing of the cold readout electronics for the MBAC is presented. Currently, the ACT collaboration is in the process of generating maps of the microwave sky using our first and second season observations. The analysis used to generate these maps requires careful data calibration to produce maps of the arcminute scale CMB temperature fluctuations. Tests and applications of several elements of the ACT calibrations are presented in the context of the second season observations. Scientific exploration has already begun on preliminary maps made using these calibrations. The final portion of this thesis is dedicated to discussing the point sources observed by the ACT. A discussion of the techniques used for point source detection and photometry is followed by a presentation of our current measurements of point source spectral indices.

The source provenance of an obsidian Eden point from Sierra County, New Mexico

DOE PAGES

Dolan, Sean Gregory; Berryman, Judy; Shackley, M. Steven

2016-01-02

Eden projectile points associated with the Cody complex are underrepresented in the late Paleoindian record of the American Southwest. EDXRF analysis of an obsidian Eden point from a site in Sierra County, New Mexico demonstrates this artifact is from the Cerro del Medio (Valles Rhyolite) source in the Jemez Mountains. Lastly, we contextualize our results by examining variability in obsidian procurement practices beyond the Cody heartland in southcentral New Mexico.

PULSED ION SOURCE

DOEpatents

Kilpatrick, W.D.

1959-04-21

A source is presented for producing high intensity pulses of ions with precise time control of pulse initiation. The approach taken is to have one of the electrodes in the source occluded with the gas to be ionized. A trigger electrode is disposed adjacent to the gas filled electrode and is pulsed with a voltage to release the gas. The other structure of the source includes an apertured anode disposed between two cathodes, the gas filled electrode and another electrode. At the same time the gas is released a low voltage pulse is applied between the anode and cathodes to establish an ionizing arc discharge. An electrode adjacent to the arc withdraws the ions.

Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

Loop heat pipes (LHPs) have been used for thermal control of several NASA and commercial orbiting spacecraft. The LHP operating temperature is governed by the saturation temperature of its compensation chamber (CC). Most LHPs use the CC temperature for feedback control of its operating temperature. There exists a thermal resistance between the heat source to be cooled by the LHP and the LHP's CC. Even if the CC set point temperature is controlled precisely, the heat source temperature will still vary with its heat output. For most applications, controlling the heat source temperature is of most interest. A logical question to ask is: "Can the heat source temperature be used for feedback control of the LHP operation?" A test program has been implemented to answer the above question. Objective is to investigate the LHP performance using the CC temperature and the heat source temperature for feedback control

Physicsdesign point for a 1MW fusion neutron source

NASA Astrophysics Data System (ADS)

Woodruff, Simon; Melnik, Paul; Sieck, Paul; Stuber, James; Romero-Talamas, Carlos; O'Bryan, John; Miller, Ronald

2016-10-01

We are developing a design point for a spheromak experiment heated by adiabatic compression for use as a compact neutron source. We utilize the CORSICA and NIMROD MHD codes as well as analytic modeling to assess a concept with target parameters R0 =0.5m, Rf =0.17m, T0 =1keV, Tf =8keV, n0 =2e20m-3 and nf = 5e21m-3, with radial convergence of C =R0/Rf =3. We present results from CORSICA showing the placement of coils and passive structure to ensure stability during compression. We specify target parameters for the compression in terms of plasma beta, formation efficiency and energy confinement. We present results simulations of magnetic compression using the NIMROD code to examine the role of rotation on the stability and confinement of the spheromak as it is compressed. Supported by DARPA Grant N66001-14-1-4044 and IAEA CRP on Compact Fusion Neutron Sources.

LEAP: Looking beyond pixels with continuous-space EstimAtion of Point sources

NASA Astrophysics Data System (ADS)

Pan, Hanjie; Simeoni, Matthieu; Hurley, Paul; Blu, Thierry; Vetterli, Martin

2017-12-01

Context. Two main classes of imaging algorithms have emerged in radio interferometry: the CLEAN algorithm and its multiple variants, and compressed-sensing inspired methods. They are both discrete in nature, and estimate source locations and intensities on a regular grid. For the traditional CLEAN-based imaging pipeline, the resolution power of the tool is limited by the width of the synthesized beam, which is inversely proportional to the largest baseline. The finite rate of innovation (FRI) framework is a robust method to find the locations of point-sources in a continuum without grid imposition. The continuous formulation makes the FRI recovery performance only dependent on the number of measurements and the number of sources in the sky. FRI can theoretically find sources below the perceived tool resolution. To date, FRI had never been tested in the extreme conditions inherent to radio astronomy: weak signal / high noise, huge data sets, large numbers of sources. Aims: The aims were (i) to adapt FRI to radio astronomy, (ii) verify it can recover sources in radio astronomy conditions with more accurate positioning than CLEAN, and possibly resolve some sources that would otherwise be missed, (iii) show that sources can be found using less data than would otherwise be required to find them, and (iv) show that FRI does not lead to an augmented rate of false positives. Methods: We implemented a continuous domain sparse reconstruction algorithm in Python. The angular resolution performance of the new algorithm was assessed under simulation, and with visibility measurements from the LOFAR telescope. Existing catalogs were used to confirm the existence of sources. Results: We adapted the FRI framework to radio interferometry, and showed that it is possible to determine accurate off-grid point-source locations and their corresponding intensities. In addition, FRI-based sparse reconstruction required less integration time and smaller baselines to reach a comparable

Distributions of organochlorine compounds in sediments from Jiulong River Estuary and adjacent Western Taiwan Strait: Implications of transport, sources and inventories.

PubMed

Wu, Yuling; Wang, Xinhong; Ya, Miaolei; Li, Yongyu; Hong, Huasheng

2016-12-01

Estuaries and coastal areas strongly influenced by terrestrial inputs resulted from anthropogenic activities. To study the distributions, origins, potential transport and burden of organochlorine compounds (OCs) from river to marginal sea, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in surface sediments collected from a subtropical estuary (Jiulong River Estuary, JRE) and the inner shelf of adjacent Western Taiwan Strait (WTS). The concentrations of OCPs and PCBs were from 5.2 to 551.7 and 1.0-8.1 ng g -1 (dry weight), respectively. OCP concentrations in the JRE were higher than in adjacent WTS, and a decreasing trend with the ascending distance from the estuary to the open sea was observed. Concentrations of DDTs were quite high in the upper reach of the estuary, inferred from antifouling paint on fishing boats of a local shipping company. According to established sediment quality guidelines, DDTs in the JRE posed potential ecological risk. HCHs in the estuary were mainly derived from the weathered HCHs preserved in the agriculture soils via local major river runoffs. OCPs patterns showed that OCPs in the south coast of WTS were resulted from local sources via river input, while OCPs in the north coast attributed to the long-range transport derived by the Fujian-Zhejiang Coastal Current. Minor variations of PCB concentrations and homologs indicated that PCBs were not the main pollutant in the agricultural region, consistent lighter PCBs reflected industrial PCBs were transported via atmospheric deposition derived by East Asia Monsoon. Moreover, the primary distribution pattern founded for DDTs and the considerable mass inventories and burdens calculated (258.1 ng cm -2 and 10.4 tones for OCPs) that higher than Pearl River Delta and Yangtze River Delta, together suggested that the contaminated sediments in the study area may be a potential source of OCPs to the global ocean. Copyright © 2016 Elsevier Ltd. All rights

Successive Two-sided Loop Jets Caused by Magnetic Reconnection between Two Adjacent Filamentary Threads

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

Tian, Zhanjun; Liu, Yu; Shen, Yuandeng

We present observational analysis of two successive two-sided loop jets observed by the ground-based New Vacuum Solar Telescope and the space-borne Solar Dynamics Observatory . The two successive two-sided loop jets manifested similar evolution processes and both were associated with the interaction of two small-scale adjacent filamentary threads, magnetic emerging, and cancellation processes at the jet’s source region. High temporal and high spatial resolution observations reveal that the two adjacent ends of the two filamentary threads are rooted in opposite magnetic polarities within the source region. The two threads approached each other, and then an obvious brightening patch is observedmore » at the interaction position. Subsequently, a pair of hot plasma ejections are observed heading in opposite directions along the paths of the two filamentary threads at a typical speed for two-sided loop jets of the order 150 km s{sup −1}. Close to the end of the second jet, we report the formation of a bright hot loop structure at the source region, which suggests the formation of new loops during the interaction. Based on the observational results, we propose that the observed two-sided loop jets are caused by magnetic reconnection between the two adjacent filamentary threads, largely different from the previous scenario that a two-sided loop jet is generated by magnetic reconnection between an emerging bipole and the overlying horizontal magnetic fields.« less

Algorithm for astronomical, point source, signal to noise ratio calculations

NASA Technical Reports Server (NTRS)

Jayroe, R. R.; Schroeder, D. J.

1984-01-01

An algorithm was developed to simulate the expected signal to noise ratios as a function of observation time in the charge coupled device detector plane of an optical telescope located outside the Earth's atmosphere for a signal star, and an optional secondary star, embedded in a uniform cosmic background. By choosing the appropriate input values, the expected point source signal to noise ratio can be computed for the Hubble Space Telescope using the Wide Field/Planetary Camera science instrument.

Waveform inversion of volcano-seismic signals for an extended source

USGS Publications Warehouse

Nakano, M.; Kumagai, H.; Chouet, B.; Dawson, P.

2007-01-01

We propose a method to investigate the dimensions and oscillation characteristics of the source of volcano-seismic signals based on waveform inversion for an extended source. An extended source is realized by a set of point sources distributed on a grid surrounding the centroid of the source in accordance with the source geometry and orientation. The source-time functions for all point sources are estimated simultaneously by waveform inversion carried out in the frequency domain. We apply a smoothing constraint to suppress short-scale noisy fluctuations of source-time functions between adjacent sources. The strength of the smoothing constraint we select is that which minimizes the Akaike Bayesian Information Criterion (ABIC). We perform a series of numerical tests to investigate the capability of our method to recover the dimensions of the source and reconstruct its oscillation characteristics. First, we use synthesized waveforms radiated by a kinematic source model that mimics the radiation from an oscillating crack. Our results demonstrate almost complete recovery of the input source dimensions and source-time function of each point source, but also point to a weaker resolution of the higher modes of crack oscillation. Second, we use synthetic waveforms generated by the acoustic resonance of a fluid-filled crack, and consider two sets of waveforms dominated by the modes with wavelengths 2L/3 and 2W/3, or L and 2L/5, where W and L are the crack width and length, respectively. Results from these tests indicate that the oscillating signature of the 2L/3 and 2W/3 modes are successfully reconstructed. The oscillating signature of the L mode is also well recovered, in contrast to results obtained for a point source for which the moment tensor description is inadequate. However, the oscillating signature of the 2L/5 mode is poorly recovered owing to weaker resolution of short-scale crack wall motions. The triggering excitations of the oscillating cracks are successfully

Search for point sources of high energy neutrinos with final data from AMANDA-II

NASA Astrophysics Data System (ADS)

Abbasi, R.; Ackermann, M.; Adams, J.; Ahlers, M.; Ahrens, J.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Baret, B.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Becka, T.; Becker, J. K.; Becker, K.-H.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser, S.; Botner, O.; Braun, J.; Breder, D.; Burgess, T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Davour, A.; Day, C. T.; Depaepe, O.; de Clercq, C.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; De Young, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke, R.; Hasegawa, Y.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hickford, S.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hughey, B.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kawai, H.; Kelley, J. L.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Lauer, R.; Leich, H.; Leier, D.; Lewis, C.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Meli, A.; Merck, M.; Messarius, T.; Mészáros, P.; Miyamoto, H.; Mohr, A.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque, S.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins, W. J.; Rodriguez, J.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Satalecka, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schultz, O.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, A. J.; Song, C.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; Viscomi, V.; Vogt, C.; Voigt, B.; Walck, C.; Waldenmaier, T.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebusch, C. H.; Wiedemann, C.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.

2009-03-01

We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E-2 neutrino fluxes from points in the northern sky, with an average upper limit of E2Φνμ+ντ≤5.2×10-11TeVcm-2s-1 on the sum of νμ and ντ fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.

Chandra Detects Enigmatic Point X-ray Sources in the Cat's Eye and the Helix Nebulae

NASA Astrophysics Data System (ADS)

Guerrero, M. A.; Gruendl, R. A.; Chu, Y.-H.; Kaler, J. B.; Williams, R. M.

2000-12-01

Central stars of planetary nebulae (PNe) with Teff greater than 100,000 K are expected to emit soft X-rays that peak below 0.1 keV. Chandra ACIS-S observations of the Cat's Eye Nebula (NGC 6543) and the Helix Nebula (NGC 7293) have detected point X-ray sources at their central stars. The point X-ray source at the central star of the Cat's Eye is both unknown previously and unexpected because the stellar temperature is only ~50,000 K. In contrast, the point X-ray source at the central star of the Helix was previously detected by ROSAT and its soft X-ray emission is expected because the stellar temperature is ~100,000 K. However, the Helix X-ray source also shows a harder X-ray component peaking at 0.8 keV that is unexpected and for which Chandra has provided the first high-resolution spectrum for detailed analysis. The spectra of the point X-ray sources in the Cat's Eye and the Helix show line features indicating an origin of thermal plasma emission. The spectrum of the Helix source can be fit by Raymond & Smith's model of plasma emission at ~9*E6 K. The spectrum of the Cat's Eye source has too few counts for a spectral fit, but appears to be consistent with plasma emission at 2-3*E6 K. The X-ray luminosities of both sources are ~5*E29 erg s-1. The observed plasma temperatures are too high for accretion disks around white dwarfs, but they could be ascribed to coronal X-ray emission. While central stars of PNe are not known to have coronae, the observed spectra are consistent with quiescent X-ray emission from dM flare stars. On the other hand, neither the central star of the Helix or the Cat's Eye are known to have a binary companion. It is possible that the X-rays from the Cat's Eye's central star originate from shocks in the stellar wind, but the central star of the Helix does not have a measurable fast stellar wind. This work is supported by the CXC grant number GO0-1004X.

A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission

NASA Astrophysics Data System (ADS)

Chen, Xi

The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years

Answering questions at the point of care: do residents practice EBM or manage information sources?

PubMed

McCord, Gary; Smucker, William D; Selius, Brian A; Hannan, Scott; Davidson, Elliot; Schrop, Susan Labuda; Rao, Vinod; Albrecht, Paula

2007-03-01

To determine the types of information sources that evidence-based medicine (EBM)-trained, family medicine residents use to answer clinical questions at the point of care, to assess whether the sources are evidence-based, and to provide suggestions for more effective information-management strategies in residency training. In 2005, trained medical students directly observed (for two half-days per physician) how 25 third-year family medicine residents retrieved information to answer clinical questions arising at the point of care and documented the type and name of each source, the retrieval location, and the estimated time spent consulting the source. An end-of-study questionnaire asked 37 full-time faculty and the participating residents about the best information sources available, subscriptions owned, why they use a personal digital assistant (PDA) to practice medicine, and their experience in preventing medical errors using a PDA. Forty-four percent of questions were answered by attending physicians, 23% by consulting PDAs, and 20% from books. Seventy-two percent of questions were answered within two minutes. Residents rated UptoDate as the best source for evidence-based information, but they used this source only five times. PDAs were used because of ease of use, time factors, and accessibility. All examples of medical errors discovered or prevented with PDA programs were medication related. None of the participants' residencies required the use of a specific medical information resource. The results support the Agency for Health Care Research and Quality's call for medical system improvements at the point of care. Additionally, it may be necessary to teach residents better information-management skills in addition to EBM skills.

Using SPARROW to Model Total Nitrogen Sources, and Transport in Rivers and Streams of California and Adjacent States, U.S.A

NASA Astrophysics Data System (ADS)

Saleh, D.; Domagalski, J. L.

2012-12-01

Sources and factors affecting the transport of total nitrogen are being evaluated for a study area that covers most of California and some areas in Oregon and Nevada, by using the SPARROW model (SPAtially Referenced Regression On Watershed attributes) developed by the U.S. Geological Survey. Mass loads of total nitrogen calculated for monitoring sites at stream gauging stations are regressed against land-use factors affecting nitrogen transport, including fertilizer use, recharge, atmospheric deposition, stream characteristics, and other factors to understand how total nitrogen is transported under average conditions. SPARROW models have been used successfully in other parts of the country to understand how nutrients are transported, and how management strategies can be formulated, such as with Total Maximum Daily Load (TMDL) assessments. Fertilizer use, atmospheric deposition, and climatic data were obtained for 2002, and loads for that year were calculated for monitored streams and point sources (mostly from wastewater treatment plants). The stream loads were calculated by using the adjusted maximum likelihood estimation method (AMLE). River discharge and nitrogen concentrations were de-trended in these calculations in order eliminate the effect of temporal changes on stream load. Effluent discharge information as well as total nitrogen concentrations from point sources were obtained from USEPA databases and from facility records. The model indicates that atmospheric deposition and fertilizer use account for a large percentage of the total nitrogen load in many of the larger watersheds throughout the study area. Point sources, on the other hand, are generally localized around large cities, are considered insignificant sources, and account for a small percentage of the total nitrogen loads throughout the study area.

40 CFR 414.100 - Applicability; description of the subcategory of direct discharge point sources that do not use...

Code of Federal Regulations, 2010 CFR

2010-07-01

... subcategory of direct discharge point sources that do not use end-of-pipe biological treatment. 414.100... AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources That Do Not Use End-of-Pipe Biological Treatment § 414.100 Applicability; description of the subcategory of...

Point-Source Contributions to the Water Quality of an Urban Stream

NASA Astrophysics Data System (ADS)

Little, S. F. B.; Young, M.; Lowry, C.

2014-12-01

Scajaquada Creek, which runs through the heart of the city of Buffalo, is a prime example of the ways in which human intervention and local geomorphology can impact water quality and urban hydrology. Beginning in the 1920's, the Creek has been partially channelized and connected to Buffalo's combined sewer system (CSS). At Forest Lawn Cemetery, where this study takes place, Scajaquada Creek emerges from a 3.5-mile tunnel built to route stream flow under the city. Collocated with the tunnel outlet is a discharge point for Buffalo's CSS, combined sewer outlet (CSO) #53. It is at this point that runoff and sanitary sewage discharge regularly during rain events. Initially, this study endeavored to create a spatial and temporal picture for this portion of the Creek, monitoring such parameters as conductivity, dissolved oxygen, pH, temperature, and turbidity, in addition to measuring Escherichia coli (E. coli) concentrations. As expected, these factors responded directly to seasonality, local geomorphology, and distance from the point source (CSO #53), displaying a overall, linear response. However, the addition of nitrate and phosphate testing to the study revealed an entirely separate signal from that previously observed. Concentrations of these parameters did not respond to location in the same manner as E. coli. Instead of decreasing with distance from the CSO, a distinct periodicity was observed, correlating with a series of outflow pipes lining the stream banks. It is hypothesized that nitrate and phosphate occurring in this stretch of Scajaquada Creek originate not from the CSO, but from fertilizers used to maintain the lawns within the subwatershed. These results provide evidence of the complexity related to water quality issues in urban streams as a result of point- and nonpoint-source hydrologic inputs.

An international point source outbreak of typhoid fever: a European collaborative investigation*

PubMed Central

Stanwell-Smith, R. E.; Ward, L. R.

1986-01-01

A point source outbreak of Salmonella typhi, degraded Vi-strain 22, affecting 32 British visitors to Kos, Greece, in 1983 was attributed by a case—control study to the consumption of a salad at one hotel. This represents the first major outbreak of typhoid fever in which a salad has been identified as the vehicle. The source of the infection was probably a carrier in the hotel staff. The investigation demonstrates the importance of national surveillance, international cooperation, and epidemiological methods in the investigation and control of major outbreaks of infection. PMID:3488842

Lumbar intervertebral disc allograft transplantation: long-term mobility and impact on the adjacent segments.

PubMed

Huang, Yong-Can; Xiao, Jun; Lu, William W; Leung, Victor Y L; Hu, Yong; Luk, Keith D K

2017-03-01

Fresh-frozen intervertebral disc (IVD) allograft transplantation has been successfully performed in the human cervical spine. Whether this non-fusion technology could truly decrease adjacent segment disease is still unknown. This study evaluated the long-term mobility of the IVD-transplanted segment and the impact on the adjacent spinal segments in a goat model. Twelve goats were used. IVD allograft transplantation was performed at lumbar L4/L5 in 5 goats; the other 7 goats were used as the untreated control (5) and for the supply of allografts (2). Post-operation lateral radiographs of the lumbar spine in the neutral, full-flexion and full-extension positions were taken at 1, 3, 6, 9 and 12 months. Disc height (DH) of the allograft and the adjacent levels was calculated and range of motion (ROM) was measured using the Cobb's method. The anatomy of the adjacent discs was observed histologically. DH of the transplanted segment was decreased significantly after 3 months but no further reduction was recorded until the final follow-up. No obvious alteration was seen in the ROM of the transplanted segment at different time points with the ROM at 12 months being comparable to that of the untreated control. The DH and ROM in the adjacent segments were well maintained during the whole observation period. At post-operative 12 months, the ROM of the adjacent levels was similar to that of the untreated control and the anatomical morphology was well preserved. Lumbar IVD allograft transplantation in goats could restore the segmental mobility and did not negatively affect the adjacent segments after 12 months.

CENTAURUS A AS A POINT SOURCE OF ULTRAHIGH ENERGY COSMIC RAYS

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

Kim, Hang Bae, E-mail: hbkim@hanyang.ac.kr

We probe the possibility that Centaurus A (Cen A) is a point source of ultrahigh energy cosmic rays (UHECRs) observed by Pierre Auger Observatory (PAO), through the statistical analysis of the arrival direction distribution. For this purpose, we set up the Cen A dominance model for the UHECR sources, in which Cen A contributes the fraction f {sub C} of the whole UHECR with energy above 5.5 Multiplication-Sign 10{sup 19} eV and the isotropic background contributes the remaining 1 - f {sub C} fraction. The effect of the intergalactic magnetic fields on the bending of the trajectory of Cen Amore » originated UHECRs is parameterized by the Gaussian smearing angle {theta} {sub s}. For the statistical analysis, we adopted the correlational angular distance distribution (CADD) for the reduction of the arrival direction distribution and the Kuiper test to compare the observed and the expected CADDs. We identify the excess of UHECRs in the Cen A direction and fit the CADD of the observed PAO data by varying two parameters f {sub C} and {theta} {sub s} of the Cen A dominance model. The best-fit parameter values are f {sub C} Almost-Equal-To 0.1 (the corresponding Cen A fraction observed at PAO is f {sub C,PAO} Almost-Equal-To 0.15, that is, about 10 out of 69 UHECRs) and {theta} {sub s} = 5 Degree-Sign with the maximum likelihood L {sub max} = 0.29. This result supports the existence of a point source smeared by the intergalactic magnetic fields in the direction of Cen A. If Cen A is actually the source responsible for the observed excess of UHECRs, the rms deflection angle of the excess UHECRs implies the order of 10 nG intergalactic magnetic field in the vicinity of Cen A.« less

40 CFR 414.90 - Applicability; description of the subcategory of direct discharge point sources that use end-of...

Code of Federal Regulations, 2010 CFR

2010-07-01

... ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources That Use End-of-Pipe... subcategory of direct discharge point sources that use end-of-pipe biological treatment. 414.90 Section 414.90... that use end-of-pipe biological treatment. The provisions of this subpart are applicable to the process...

Search for Point Sources of High Energy Neutrinos with Final Data from AMANDA-II

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

IceCube Collaboration; Klein, Spencer

2009-03-06

We present a search for point sources of high energy neutrinos using 3.8 years of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the Northern Sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E{sup -2} neutrino fluxes from points in the Northern Sky, with an average upper limit of E{supmore » 2}{Phi}{sub {nu}{sub {mu}}+{nu}{sub {tau}}} {le} 5.2 x 10{sup -11} TeV cm{sup -2} s{sup -1} on the sum of {nu}{sub {mu}} and {nu}{sub {tau}} fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.« less

Search for point sources of high energy neutrinos with final data from AMANDA-II

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

Abbasi, R.; Andeen, K.; Baker, M.

2009-03-15

We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E{sup -2} neutrino fluxes from points in the northern sky, with an average upper limit of E{supmore » 2}{phi}{sub {nu}{sub {mu}}}{sub +{nu}{sub {tau}}}{<=}5.2x10{sup -11} TeV cm{sup -2} s{sup -1} on the sum of {nu}{sub {mu}} and {nu}{sub {tau}} fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.« less

Identifying and characterizing major emission point sources as a basis for geospatial distribution of mercury emissions inventories

NASA Astrophysics Data System (ADS)

Steenhuisen, Frits; Wilson, Simon J.

2015-07-01

Mercury is a global pollutant that poses threats to ecosystem and human health. Due to its global transport, mercury contamination is found in regions of the Earth that are remote from major emissions areas, including the Polar regions. Global anthropogenic emission inventories identify important sectors and industries responsible for emissions at a national level; however, to be useful for air transport modelling, more precise information on the locations of emission is required. This paper describes the methodology applied, and the results of work that was conducted to assign anthropogenic mercury emissions to point sources as part of geospatial mapping of the 2010 global anthropogenic mercury emissions inventory prepared by AMAP/UNEP. Major point-source emission sectors addressed in this work account for about 850 tonnes of the emissions included in the 2010 inventory. This work allocated more than 90% of these emissions to some 4600 identified point source locations, including significantly more point source locations in Africa, Asia, Australia and South America than had been identified during previous work to geospatially-distribute the 2005 global inventory. The results demonstrate the utility and the limitations of using existing, mainly public domain resources to accomplish this work. Assumptions necessary to make use of selected online resources are discussed, as are artefacts that can arise when these assumptions are applied to assign (national-sector) emissions estimates to point sources in various countries and regions. Notwithstanding the limitations of the available information, the value of this procedure over alternative methods commonly used to geo-spatially distribute emissions, such as use of 'proxy' datasets to represent emissions patterns, is illustrated. Improvements in information that would facilitate greater use of these methods in future work to assign emissions to point-sources are discussed. These include improvements to both national

Mortality rates of pathogen indicator microorganisms discharged from point and non-point sources in an urban area.

PubMed

Kim, Geonha; Hur, Jin

2010-01-01

This research measured the mortality rates of pathogen indicator microorganisms discharged from various point and non-point sources in an urban area. Water samples were collected from a domestic sewer, a combined sewer overflow, the effluent of a wastewater treatment plant, and an urban river. Mortality rates of indicator microorganisms in sediment of an urban river were also measured. Mortality rates of indicator microorganisms in domestic sewage, estimated by assuming first order kinetics at 20 degrees C were 0.197 day(-1), 0.234 day(-1), 0.258 day(-1) and 0.276 day(-1) for total coliform, fecal coliform, Escherichia coli, and fecal streptococci, respectively. Effects of temperature, sunlight irradiation and settlement on the mortality rate were measured. Results of this research can be used as input data for water quality modeling or can be used as design factors for treatment facilities.

Point Source X-Ray Lithography System for Sub-0.15 Micron Design Rules

DTIC Science & Technology

1998-05-22

consist of a SAL developed stepper, an SRL developed Dense Plasma Focus , (DPF), X-Ray source, and a CXrL developed beam line. The system will be...existing machine that used spark gap switching, SRL has developed an all solid state driver and improved head electrode assembly for their dense plasma ... focus X-Ray source. Likewise, SAL has used their existing Model 4 stepper installed at CXrL as a design starting point, and has developed an advanced

Point source pollution and variability of nitrate concentrations in water from shallow aquifers

NASA Astrophysics Data System (ADS)

Nemčić-Jurec, Jasna; Jazbec, Anamarija

2017-06-01

Agriculture is one of the several major sources of nitrate pollution, and therefore the EU Nitrate Directive, designed to decrease pollution, has been implemented. Point sources like septic systems and broken sewage systems also contribute to water pollution. Pollution of groundwater by nitrate from 19 shallow wells was studied in a typical agricultural region, middle Podravina, in northwest Croatia. The concentration of nitrate ranged from <0.1 to 367 mg/l in water from wells, and 29.8 % of 253 total samples were above maximum acceptable value of 50 mg/l (MAV). Among regions R1-R6, there was no statistically significant difference in nitrate concentrations ( F = 1.98; p = 0.15) during the years 2002-2007. Average concentrations of nitrate in all 19 wells for all the analyzed years were between recommended limit value of 25 mg/l (RLV) and MAV except in 2002 (concentration was under RLV). The results of the repeated measures ANOVA showed statistically significant differences between the wells at the point source distance (proximity) of <10 m, compared to the wells at the point source distance of >20 m ( F = 10.6; p < 0.001). Average annual concentrations of nitrate during the years studied are not statistically different, but interaction between proximity and years is statistically significant ( F = 2.07; p = 0.04). Results of k-means clustering confirmed division into four clusters according to the pollution. Principal component analysis showed that there is only one significant factor, proximity, which explains 91.6 % of the total variability of nitrate. Differences in water quality were found as a result of different environmental factors. These results will contribute to the implementation of the Nitrate Directive in Croatia and the EU.

Point-like neutron source based on high-current electron cyclotron resonance ion source with powerful millimeter wave plasma heating

NASA Astrophysics Data System (ADS)

Golubev, S. V.; Skalyga, V. A.; Izotov, I. V.; Sidorov, A. V.

2018-01-01

A possibility of an intense deuterium ion beam creation for a compact powerful point-like neutron source is discussed. The fusion takes place due to bombardment of deuterium (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ways of high-current and low emittance ion beam formation from the plasma of quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance discharge in an open magnetic trap sustained by powerful microwave radiation are investigated.

Spillover from adjacent crop and forest habitats shapes carabid beetle assemblages in fragmented semi-natural grasslands.

PubMed

Schneider, Gudrun; Krauss, Jochen; Boetzl, Fabian A; Fritze, Michael-Andreas; Steffan-Dewenter, Ingolf

2016-12-01

Semi-natural grasslands in Europe are insect biodiversity hotspots and important source habitats delivering ecosystem services to adjacent agricultural land by species spillover. However, this spillover might also occur in the opposite direction, affecting the diversity of semi-natural grasslands. This opposite spillover has got little attention in scientific literature even though generalist species penetrating into the grasslands can affect local biotic interactions, community composition and the conservation value of grassland habitats. In this study, we examined spillover effects from two different adjacent habitat types on carabid beetle assemblages in 20 semi-natural calcareous grasslands. The grasslands were either adjacent to a cereal crop field or to a coniferous forest. We found distinct differences in carabid beetle assemblages in calcareous grasslands depending on adjacent habitat type. Species richness and activity density were higher, but the evenness was lower in calcareous grasslands adjacent to crop fields compared with calcareous grasslands adjacent to coniferous forests. Further, we found a strong spillover of carabid beetles from adjacent crop fields after crop harvest, which may result in transiently increased predation pressure and resource competition in calcareous grasslands. Our results highlight that species composition, diversity and presumably ecosystem functions within semi-natural habitats are affected by the type and management of surrounding habitats. This needs to be considered by nature conservation measures, which aim to protect the unique insect communities of semi-natural European grasslands.

A Deep XMM-Newton Survey of M33: Point-source Catalog, Source Detection, and Characterization of Overlapping Fields

NASA Astrophysics Data System (ADS)

Williams, Benjamin F.; Wold, Brian; Haberl, Frank; Garofali, Kristen; Blair, William P.; Gaetz, Terrance J.; Kuntz, K. D.; Long, Knox S.; Pannuti, Thomas G.; Pietsch, Wolfgang; Plucinsky, Paul P.; Winkler, P. Frank

2015-05-01

We have obtained a deep 8 field XMM-Newton mosaic of M33 covering the galaxy out to the D25 isophote and beyond to a limiting 0.2-4.5 keV unabsorbed flux of 5 × 10-16 erg cm-2 s-1 (L \\gt 4 × 1034 erg s-1 at the distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). Here, we describe the methods we used to identify and characterize 1296 point sources in the 8 fields. We compare our resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ˜15% of the 391 bright sources with L \\gt 3.6 × 1035 erg s-1 are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)-log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, we note the discovery of an interesting new transient X-ray source, which we are unable to classify.

Topography adjacent to Signal Corps Radar (S.C.R.) 296 Station 5, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Topography adjacent to Signal Corps Radar (S.C.R.) 296 Station 5, showing conditions before construction, May 28, 1943, this drawing shows the Bonita Ridge access road retaining wall and general conditions at Bonita Ridge before the construction of Signal Corps Radar (S.C.R.) 296 Station 5 - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

Calculation and analysis of the non-point source pollution in the upstream watershed of the Panjiakou Reservoir, People's Republic of China

NASA Astrophysics Data System (ADS)

Zhang, S.; Tang, L.

2007-05-01

Panjiakou Reservoir is an important drinking water resource in Haihe River Basin, Hebei Province, People's Republic of China. The upstream watershed area is about 35,000 square kilometers. Recently, the water pollution in the reservoir is becoming more serious owing to the non-point pollution as well as point source pollution on the upstream watershed. To effectively manage the reservoir and watershed and develop a plan to reduce pollutant loads, the loading of non-point and point pollution and their distribution on the upstream watershed must be understood fully. The SWAT model is used to simulate the production and transportation of the non-point source pollutants in the upstream watershed of the Panjiakou Reservoir. The loadings of non-point source pollutants are calculated for different hydrologic years and the spatial and temporal characteristics of non-point source pollution are studied. The stream network and topographic characteristics of the stream network and sub-basins are all derived from the DEM by ArcGIS software. The soil and land use data are reclassified and the soil physical properties database file is created for the model. The SWAT model was calibrated with observed data of several hydrologic monitoring stations in the study area. The results of the calibration show that the model performs fairly well. Then the calibrated model was used to calculate the loadings of non-point source pollutants for a wet year, a normal year and a dry year respectively. The time and space distribution of flow, sediment and non-point source pollution were analyzed depending on the simulated results. The comparison of different hydrologic years on calculation results is dramatic. The loading of non-point source pollution in the wet year is relatively larger but smaller in the dry year since the non-point source pollutants are mainly transported through the runoff. The pollution loading within a year is mainly produced in the flood season. Because SWAT is a

Applicability of the single equivalent point dipole model to represent a spatially distributed bio-electrical source

NASA Technical Reports Server (NTRS)

Armoundas, A. A.; Feldman, A. B.; Sherman, D. A.; Cohen, R. J.

2001-01-01

Although the single equivalent point dipole model has been used to represent well-localised bio-electrical sources, in realistic situations the source is distributed. Consequently, position estimates of point dipoles determined by inverse algorithms suffer from systematic error due to the non-exact applicability of the inverse model. In realistic situations, this systematic error cannot be avoided, a limitation that is independent of the complexity of the torso model used. This study quantitatively investigates the intrinsic limitations in the assignment of a location to the equivalent dipole due to distributed electrical source. To simulate arrhythmic activity in the heart, a model of a wave of depolarisation spreading from a focal source over the surface of a spherical shell is used. The activity is represented by a sequence of concentric belt sources (obtained by slicing the shell with a sequence of parallel plane pairs), with constant dipole moment per unit length (circumferentially) directed parallel to the propagation direction. The distributed source is represented by N dipoles at equal arc lengths along the belt. The sum of the dipole potentials is calculated at predefined electrode locations. The inverse problem involves finding a single equivalent point dipole that best reproduces the electrode potentials due to the distributed source. The inverse problem is implemented by minimising the chi2 per degree of freedom. It is found that the trajectory traced by the equivalent dipole is sensitive to the location of the spherical shell relative to the fixed electrodes. It is shown that this trajectory does not coincide with the sequence of geometrical centres of the consecutive belt sources. For distributed sources within a bounded spherical medium, displaced from the sphere's centre by 40% of the sphere's radius, it is found that the error in the equivalent dipole location varies from 3 to 20% for sources with size between 5 and 50% of the sphere's radius

Proposal on a sustainable strategy to avoid point source pollution of water with plant protection products.

PubMed

Mestdagh, Inge; Bonicelli, Bernard; Laplana, Ramon; Roettele, Manfred

2009-01-01

Based on the results and lessons learned from the TOPPS project (Training the Operators to prevent Pollution from Point Sources), a proposal on a sustainable strategy to avoid point source pollution from Plant Protection Products (PPPs) was made. Within this TOPPS project (2005-2008), stakeholders were interviewed and research and analysis were done in 6 pilot catchment areas (BE, FR, DE, DK, IT, PL). Next, there was a repeated survey on operators' perception and opinion to measure changes resulting from TOPPS activities and good and bad practices were defined based on the Best Management Practices (risk analysis). Aim of the proposal is to suggest a strategy considering the differences between countries which can be implemented on Member State level in order to avoid PPP pollution of water through point sources. The methodology used for the up-scaLing proposal consists of the analysis of the current situation, a gap analysis, a consistency analysis and organisational structures for implementation. The up-scaling proposal focuses on the behaviour of the operators, on the equipment and infrastructure available with the operators. The proposal defines implementation structures to support correct behaviour through the development and updating of Best Management Practices (BMPs) and through the transfer and the implementation of these BMPs. Next, the proposal also defines requirements for the improvement of equipment and infrastructure based on the defined key factors related to point source pollution. It also contains cost estimates for technical and infrastructure upgrades to comply with BMPs.

Effects of pointing compared with naming and observing during encoding on item and source memory in young and older adults.

PubMed

Ouwehand, Kim; van Gog, Tamara; Paas, Fred

2016-10-01

Research showed that source memory functioning declines with ageing. Evidence suggests that encoding visual stimuli with manual pointing in addition to visual observation can have a positive effect on spatial memory compared with visual observation only. The present study investigated whether pointing at picture locations during encoding would lead to better spatial source memory than naming (Experiment 1) and visual observation only (Experiment 2) in young and older adults. Experiment 3 investigated whether response modality during the test phase would influence spatial source memory performance. Experiments 1 and 2 supported the hypothesis that pointing during encoding led to better source memory for picture locations than naming or observation only. Young adults outperformed older adults on the source memory but not the item memory task in both Experiments 1 and 2. In Experiments 1 and 2, participants manually responded in the test phase. Experiment 3 showed that if participants had to verbally respond in the test phase, the positive effect of pointing compared with naming during encoding disappeared. The results suggest that pointing at picture locations during encoding can enhance spatial source memory in both young and older adults, but only if the response modality is congruent in the test phase.

[Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

PubMed

Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

2015-07-01

Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

plas.io: Open Source, Browser-based WebGL Point Cloud Visualization

NASA Astrophysics Data System (ADS)

Butler, H.; Finnegan, D. C.; Gadomski, P. J.; Verma, U. K.

2014-12-01

Point cloud data, in the form of Light Detection and Ranging (LiDAR), RADAR, or semi-global matching (SGM) image processing, are rapidly becoming a foundational data type to quantify and characterize geospatial processes. Visualization of these data, due to overall volume and irregular arrangement, is often difficult. Technological advancement in web browsers, in the form of WebGL and HTML5, have made interactivity and visualization capabilities ubiquitously available which once only existed in desktop software. plas.io is an open source JavaScript application that provides point cloud visualization, exploitation, and compression features in a web-browser platform, reducing the reliance for client-based desktop applications. The wide reach of WebGL and browser-based technologies mean plas.io's capabilities can be delivered to a diverse list of devices -- from phones and tablets to high-end workstations -- with very little custom software development. These properties make plas.io an ideal open platform for researchers and software developers to communicate visualizations of complex and rich point cloud data to devices to which everyone has easy access.

Strategies for lidar characterization of particulates from point and area sources

NASA Astrophysics Data System (ADS)

Wojcik, Michael D.; Moore, Kori D.; Martin, Randal S.; Hatfield, Jerry

2010-10-01

Use of ground based remote sensing technologies such as scanning lidar systems (light detection and ranging) has gained traction in characterizing ambient aerosols due to some key advantages such as wide area of regard (10 km2), fast response time, high spatial resolution (<10 m) and high sensitivity. Energy Dynamics Laboratory and Utah State University, in conjunction with the USDA-ARS, has developed a three-wavelength scanning lidar system called Aglite that has been successfully deployed to characterize particle motion, concentration, and size distribution at both point and diffuse area sources in agricultural and industrial settings. A suite of massbased and size distribution point sensors are used to locally calibrate the lidar. Generating meaningful particle size distribution, mass concentration, and emission rate results based on lidar data is dependent on strategic onsite deployment of these point sensors with successful local meteorological measurements. Deployment strategies learned from field use of this entire measurement system over five years include the characterization of local meteorology and its predictability prior to deployment, the placement of point sensors to prevent contamination and overloading, the positioning of the lidar and beam plane to avoid hard target interferences, and the usefulness of photographic and written observational data.

A Comparative Analysis of Vibrio cholerae Contamination in Point-of-Drinking and Source Water in a Low-Income Urban Community, Bangladesh.

PubMed

Ferdous, Jannatul; Sultana, Rebeca; Rashid, Ridwan B; Tasnimuzzaman, Md; Nordland, Andreas; Begum, Anowara; Jensen, Peter K M

2018-01-01

Bangladesh is a cholera endemic country with a population at high risk of cholera. Toxigenic and non-toxigenic Vibrio cholerae ( V. cholerae ) can cause cholera and cholera-like diarrheal illness and outbreaks. Drinking water is one of the primary routes of cholera transmission in Bangladesh. The aim of this study was to conduct a comparative assessment of the presence of V. cholerae between point-of-drinking water and source water, and to investigate the variability of virulence profile using molecular methods of a densely populated low-income settlement of Dhaka, Bangladesh. Water samples were collected and tested for V. cholerae from "point-of-drinking" and "source" in 477 study households in routine visits at 6 week intervals over a period of 14 months. We studied the virulence profiles of V. cholerae positive water samples using 22 different virulence gene markers present in toxigenic O1/O139 and non-O1/O139 V. cholerae using polymerase chain reaction (PCR). A total of 1,463 water samples were collected, with 1,082 samples from point-of-drinking water in 388 households and 381 samples from 66 water sources. V. cholerae was detected in 10% of point-of-drinking water samples and in 9% of source water samples. Twenty-three percent of households and 38% of the sources were positive for V. cholerae in at least one visit. Samples collected from point-of-drinking and linked sources in a 7 day interval showed significantly higher odds ( P < 0.05) of V. cholerae presence in point-of-drinking compared to source [OR = 17.24 (95% CI = 7.14-42.89)] water. Based on the 7 day interval data, 53% (17/32) of source water samples were negative for V. cholerae while linked point-of-drinking water samples were positive. There were significantly higher odds ( p < 0.05) of the presence of V. cholerae O1 [OR = 9.13 (95% CI = 2.85-29.26)] and V. cholerae O139 [OR = 4.73 (95% CI = 1.19-18.79)] in source water samples than in point-of-drinking water samples. Contamination of water at

Point source moving above a finite impedance reflecting plane - Experiment and theory

NASA Technical Reports Server (NTRS)

Norum, T. D.; Liu, C. H.

1978-01-01

A widely used experimental version of the acoustic monopole consists of an acoustic driver of restricted opening forced by a discrete frequency oscillator. To investigate the effects of forward motion on this source, it was mounted above an automobile and driven over an asphalt surface at constant speed past a microphone array. The shapes of the received signal were compared to results computed from an analysis of a fluctuating-mass-type point source moving above a finite impedance reflecting plane. Good agreement was found between experiment and theory when a complex normal impedance representative of a fairly hard acoustic surface was used in the analysis.

Experimental and Analytical Studies of Shielding Concepts for Point Sources and Jet Noises.

NASA Astrophysics Data System (ADS)

Wong, Raymond Lee Man

This analytical and experimental study explores concepts for jet noise shielding. Model experiments centre on solid planar shields, simulating engine-over-wing installations, and 'sugar scoop' shields. Tradeoff on effective shielding length is set by interference 'edge noise' as the shield trailing edge approaches the spreading jet. Edge noise is minimized by (i) hyperbolic cutouts which trim off the portions of most intense interference between the jet flow and the barrier and (ii) hybrid shields--a thermal refractive extension (a flame); for (ii) the tradeoff is combustion noise. In general, shielding attenuation increases steadily with frequency, following low frequency enhancement by edge noise. Although broadband attenuation is typically only several dB, the reduction of the subjectively weighted perceived noise levels is higher. In addition, calculated ground contours of peak PN dB show a substantial contraction due to shielding: this reaches 66% for one of the 'sugar scoop' shields for the 90 PN dB contour. The experiments are complemented by analytical predictions. They are divided into an engineering scheme for jet noise shielding and more rigorous analysis for point source shielding. The former approach combines point source shielding with a suitable jet source distribution. The results are synthesized into a predictive algorithm for jet noise shielding: the jet is modelled as a line distribution of incoherent sources with narrow band frequency (TURN)(axial distance)('-1). The predictive version agrees well with experiment (1 to 1.5 dB) up to moderate frequencies. The insertion loss deduced from the point source measurements for semi-infinite as well as finite rectangular shields agrees rather well with theoretical calculation based on the exact half plane solution and the superposition of asymptotic closed-form solutions. An approximate theory, the Maggi-Rubinowicz line integral, is found to yield reasonable predictions for thin barriers including

Search for neutrino point sources with ANTARES 2007-2012 data

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

Zornoza, J. D.

2014-11-18

Neutrinos are unique probes to study the high energy Universe, since they are neutral, only interact weakly and are stable. Furthermore, they can provide key information about several fundamental questions in Physics like the origin of cosmic rays and the nature of dark matter. The ANTARES neutrino telescope, installed in the Mediterranean Sea, has been taking data since 2007. In this paper we review the results concerning the search for point sources of cosmic neutrinos, using data of 2007–2012. Two main strategies have been followed: to look towards the direction of sources candidate to emmit neutrinos and to make anmore » all-sky scan. Although no significant cluster has been found above the background, flux limits have been set at the level of E{sup 2}φν{sup 90CL}∼1–2×10{sup −8} GeV cm{sup −}2s{sup −1}.« less

Providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

DOEpatents

Archer, Charles J; Faraj, Ahmad A; Inglett, Todd A; Ratterman, Joseph D

2013-04-16

Methods, apparatus, and products are disclosed for providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: receiving a network packet in a compute node, the network packet specifying a destination compute node; selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node; and forwarding the network packet along the selected link to the adjacent compute node connected to the compute node through the selected link.

A study on the evaporation process with multiple point-sources

NASA Astrophysics Data System (ADS)

Jun, Sunghoon; Kim, Minseok; Kim, Suk Han; Lee, Moon Yong; Lee, Eung Ki

2013-10-01

In Organic Light Emitting Display (OLED) manufacturing processes, there is a need to enlarge the mother glass substrate to raise its productivity and enable OLED TV. The larger the size of the glass substrate, the more difficult it is to establish a uniform thickness profile of the organic thin-film layer in the vacuum evaporation process. In this paper, a multiple point-source evaporation process is proposed to deposit a uniform organic layer uniformly. Using this method, a uniformity of 3.75% was achieved along a 1,300 mm length of Gen. 5.5 glass substrate (1300 × 1500 mm2).

A Comparative Analysis of Vibrio cholerae Contamination in Point-of-Drinking and Source Water in a Low-Income Urban Community, Bangladesh

PubMed Central

Ferdous, Jannatul; Sultana, Rebeca; Rashid, Ridwan B.; Tasnimuzzaman, Md.; Nordland, Andreas; Begum, Anowara; Jensen, Peter K. M.

2018-01-01

Bangladesh is a cholera endemic country with a population at high risk of cholera. Toxigenic and non-toxigenic Vibrio cholerae (V. cholerae) can cause cholera and cholera-like diarrheal illness and outbreaks. Drinking water is one of the primary routes of cholera transmission in Bangladesh. The aim of this study was to conduct a comparative assessment of the presence of V. cholerae between point-of-drinking water and source water, and to investigate the variability of virulence profile using molecular methods of a densely populated low-income settlement of Dhaka, Bangladesh. Water samples were collected and tested for V. cholerae from “point-of-drinking” and “source” in 477 study households in routine visits at 6 week intervals over a period of 14 months. We studied the virulence profiles of V. cholerae positive water samples using 22 different virulence gene markers present in toxigenic O1/O139 and non-O1/O139 V. cholerae using polymerase chain reaction (PCR). A total of 1,463 water samples were collected, with 1,082 samples from point-of-drinking water in 388 households and 381 samples from 66 water sources. V. cholerae was detected in 10% of point-of-drinking water samples and in 9% of source water samples. Twenty-three percent of households and 38% of the sources were positive for V. cholerae in at least one visit. Samples collected from point-of-drinking and linked sources in a 7 day interval showed significantly higher odds (P < 0.05) of V. cholerae presence in point-of-drinking compared to source [OR = 17.24 (95% CI = 7.14–42.89)] water. Based on the 7 day interval data, 53% (17/32) of source water samples were negative for V. cholerae while linked point-of-drinking water samples were positive. There were significantly higher odds (p < 0.05) of the presence of V. cholerae O1 [OR = 9.13 (95% CI = 2.85–29.26)] and V. cholerae O139 [OR = 4.73 (95% CI = 1.19–18.79)] in source water samples than in point-of-drinking water samples. Contamination of

Powerful model for the point source sky: Far-ultraviolet and enhanced midinfrared performance

NASA Technical Reports Server (NTRS)

Cohen, Martin

1994-01-01

I report further developments of the Wainscoat et al. (1992) model originally created for the point source infrared sky. The already detailed and realistic representation of the Galaxy (disk, spiral arms and local spur, molecular ring, bulge, spheroid) has been improved, guided by CO surveys of local molecular clouds, and by the inclusion of a component to represent Gould's Belt. The newest version of the model is very well validated by Infrared Astronomy Satellite (IRAS) source counts. A major new aspect is the extension of the same model down to the far ultraviolet. I compare predicted and observed far-utraviolet source counts from the Apollo 16 'S201' experiment (1400 A) and the TD1 satellite (for the 1565 A band).

The Herschel Virgo Cluster Survey. XVII. SPIRE point-source catalogs and number counts

NASA Astrophysics Data System (ADS)

Pappalardo, Ciro; Bendo, George J.; Bianchi, Simone; Hunt, Leslie; Zibetti, Stefano; Corbelli, Edvige; di Serego Alighieri, Sperello; Grossi, Marco; Davies, Jonathan; Baes, Maarten; De Looze, Ilse; Fritz, Jacopo; Pohlen, Michael; Smith, Matthew W. L.; Verstappen, Joris; Boquien, Médéric; Boselli, Alessandro; Cortese, Luca; Hughes, Thomas; Viaene, Sebastien; Bizzocchi, Luca; Clemens, Marcel

2015-01-01

Aims: We present three independent catalogs of point-sources extracted from SPIRE images at 250, 350, and 500 μm, acquired with the Herschel Space Observatory as a part of the Herschel Virgo Cluster Survey (HeViCS). The catalogs have been cross-correlated to consistently extract the photometry at SPIRE wavelengths for each object. Methods: Sources have been detected using an iterative loop. The source positions are determined by estimating the likelihood to be a real source for each peak on the maps, according to the criterion defined in the sourceExtractorSussextractor task. The flux densities are estimated using the sourceExtractorTimeline, a timeline-based point source fitter that also determines the fitting procedure with the width of the Gaussian that best reproduces the source considered. Afterwards, each source is subtracted from the maps, removing a Gaussian function in every position with the full width half maximum equal to that estimated in sourceExtractorTimeline. This procedure improves the robustness of our algorithm in terms of source identification. We calculate the completeness and the flux accuracy by injecting artificial sources in the timeline and estimate the reliability of the catalog using a permutation method. Results: The HeViCS catalogs contain about 52 000, 42 200, and 18 700 sources selected at 250, 350, and 500 μm above 3σ and are ~75%, 62%, and 50% complete at flux densities of 20 mJy at 250, 350, 500 μm, respectively. We then measured source number counts at 250, 350, and 500 μm and compare them with previous data and semi-analytical models. We also cross-correlated the catalogs with the Sloan Digital Sky Survey to investigate the redshift distribution of the nearby sources. From this cross-correlation, we select ~2000 sources with reliable fluxes and a high signal-to-noise ratio, finding an average redshift z ~ 0.3 ± 0.22 and 0.25 (16-84 percentile). Conclusions: The number counts at 250, 350, and 500 μm show an increase in

Spherical earth gravity and magnetic anomaly analysis by equivalent point source inversion

NASA Technical Reports Server (NTRS)

Von Frese, R. R. B.; Hinze, W. J.; Braile, L. W.

1981-01-01

To facilitate geologic interpretation of satellite elevation potential field data, analysis techniques are developed and verified in the spherical domain that are commensurate with conventional flat earth methods of potential field interpretation. A powerful approach to the spherical earth problem relates potential field anomalies to a distribution of equivalent point sources by least squares matrix inversion. Linear transformations of the equivalent source field lead to corresponding geoidal anomalies, pseudo-anomalies, vector anomaly components, spatial derivatives, continuations, and differential magnetic pole reductions. A number of examples using 1 deg-averaged surface free-air gravity anomalies of POGO satellite magnetometer data for the United States, Mexico, and Central America illustrate the capabilities of the method.

Point spread functions for earthquake source imaging: An interpretation based on seismic interferometry

USGS Publications Warehouse

Nakahara, Hisashi; Haney, Matt

2015-01-01

Recently, various methods have been proposed and applied for earthquake source imaging, and theoretical relationships among the methods have been studied. In this study, we make a follow-up theoretical study to better understand the meanings of earthquake source imaging. For imaging problems, the point spread function (PSF) is used to describe the degree of blurring and degradation in an obtained image of a target object as a response of an imaging system. In this study, we formulate PSFs for earthquake source imaging. By calculating the PSFs, we find that waveform source inversion methods remove the effect of the PSF and are free from artifacts. However, the other source imaging methods are affected by the PSF and suffer from the effect of blurring and degradation due to the restricted distribution of receivers. Consequently, careful treatment of the effect is necessary when using the source imaging methods other than waveform inversions. Moreover, the PSF for source imaging is found to have a link with seismic interferometry with the help of the source-receiver reciprocity of Green’s functions. In particular, the PSF can be related to Green’s function for cases in which receivers are distributed so as to completely surround the sources. Furthermore, the PSF acts as a low-pass filter. Given these considerations, the PSF is quite useful for understanding the physical meaning of earthquake source imaging.

Modification of Point Counts for Surveying Cropland Birds

Treesearch

Kathryn Freemark; Catherine Rogers

1995-01-01

As part of a comparative study of agricultural impacts on wildlife, modifications to the point count method were evaluated for surveying birds in, and adjacent to, cropland during the breeding season (May to early July) in Ontario. Location in the field, observation direction and distance, number of visits, and number of study sites per farm were examined using point...

Fast generation of complex modulation video holograms using temporal redundancy compression and hybrid point-source/wave-field approaches

NASA Astrophysics Data System (ADS)

Gilles, Antonin; Gioia, Patrick; Cozot, Rémi; Morin, Luce

2015-09-01

The hybrid point-source/wave-field method is a newly proposed approach for Computer-Generated Hologram (CGH) calculation, based on the slicing of the scene into several depth layers parallel to the hologram plane. The complex wave scattered by each depth layer is then computed using either a wave-field or a point-source approach according to a threshold criterion on the number of points within the layer. Finally, the complex waves scattered by all the depth layers are summed up in order to obtain the final CGH. Although outperforming both point-source and wave-field methods without producing any visible artifact, this approach has not yet been used for animated holograms, and the possible exploitation of temporal redundancies has not been studied. In this paper, we propose a fast computation of video holograms by taking into account those redundancies. Our algorithm consists of three steps. First, intensity and depth data of the current 3D video frame are extracted and compared with those of the previous frame in order to remove temporally redundant data. Then the CGH pattern for this compressed frame is generated using the hybrid point-source/wave-field approach. The resulting CGH pattern is finally transmitted to the video output and stored in the previous frame buffer. Experimental results reveal that our proposed method is able to produce video holograms at interactive rates without producing any visible artifact.

Using the Chandra Source-Finding Algorithm to Automatically Identify Solar X-ray Bright Points

NASA Technical Reports Server (NTRS)

Adams, Mitzi L.; Tennant, A.; Cirtain, J. M.

2009-01-01

This poster details a technique of bright point identification that is used to find sources in Chandra X-ray data. The algorithm, part of a program called LEXTRCT, searches for regions of a given size that are above a minimum signal to noise ratio. The algorithm allows selected pixels to be excluded from the source-finding, thus allowing exclusion of saturated pixels (from flares and/or active regions). For Chandra data the noise is determined by photon counting statistics, whereas solar telescopes typically integrate a flux. Thus the calculated signal-to-noise ratio is incorrect, but we find we can scale the number to get reasonable results. For example, Nakakubo and Hara (1998) find 297 bright points in a September 11, 1996 Yohkoh image; with judicious selection of signal-to-noise ratio, our algorithm finds 300 sources. To further assess the efficacy of the algorithm, we analyze a SOHO/EIT image (195 Angstroms) and compare results with those published in the literature (McIntosh and Gurman, 2005). Finally, we analyze three sets of data from Hinode, representing different parts of the decline to minimum of the solar cycle.

40 CFR 414.110 - Applicability; description of the subcategory of indirect discharge point sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the subcategory of indirect discharge point sources. 414.110 Section 414.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND...

40 CFR 414.110 - Applicability; description of the subcategory of indirect discharge point sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the subcategory of indirect discharge point sources. 414.110 Section 414.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND...

40 CFR 414.110 - Applicability; description of the subcategory of indirect discharge point sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the subcategory of indirect discharge point sources. 414.110 Section 414.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND...

40 CFR 414.110 - Applicability; description of the subcategory of indirect discharge point sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the subcategory of indirect discharge point sources. 414.110 Section 414.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND...

40 CFR 414.110 - Applicability; description of the subcategory of indirect discharge point sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the subcategory of indirect discharge point sources. 414.110 Section 414.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND...

Test method for telescopes using a point source at a finite distance

NASA Technical Reports Server (NTRS)

Griner, D. B.; Zissa, D. E.; Korsch, D.

1985-01-01

A test method for telescopes that makes use of a focused ring formed by an annular aperture when using a point source at a finite distance is evaluated theoretically and experimentally. The results show that the concept can be applied to near-normal, as well as grazing incidence. It is particularly suited for X-ray telescopes because of their intrinsically narrow annular apertures, and because of the largely reduced diffraction effects.

Non-fluorescent nanoscopic monitoring of a single trapped nanoparticle via nonlinear point sources.

PubMed

Yoon, Seung Ju; Lee, Jungmin; Han, Sangyoon; Kim, Chang-Kyu; Ahn, Chi Won; Kim, Myung-Ki; Lee, Yong-Hee

2018-06-07

Detection of single nanoparticles or molecules has often relied on fluorescent schemes. However, fluorescence detection approaches limit the range of investigable nanoparticles or molecules. Here, we propose and demonstrate a non-fluorescent nanoscopic trapping and monitoring platform that can trap a single sub-5-nm particle and monitor it with a pair of floating nonlinear point sources. The resonant photon funnelling into an extremely small volume of ~5 × 5 × 7 nm 3 through the three-dimensionally tapered 5-nm-gap plasmonic nanoantenna enables the trapping of a 4-nm CdSe/ZnS quantum dot with low intensity of a 1560-nm continuous-wave laser, and the pumping of 1560-nm femtosecond laser pulses creates strong background-free second-harmonic point illumination sources at the two vertices of the nanoantenna. Under the stable trapping conditions, intermittent but intense nonlinear optical spikes are observed on top of the second-harmonic signal plateau, which is identified as the 3.0-Hz Kramers hopping of the quantum dot trapped in the 5-nm gap.

Source apportionment of nitrogen and phosphorus from non-point source pollution in Nansi Lake Basin, China.

PubMed

Zhang, Bao-Lei; Cui, Bo-Hao; Zhang, Shu-Min; Wu, Quan-Yuan; Yao, Lei

2018-05-03

Nitrogen (N) and phosphorus (P) from non-point source (NPS) pollution in Nansi Lake Basin greatly influenced the water quality of Nansi Lake, which is the determinant factor for the success of East Route of South-North Water Transfer Project in China. This research improved Johnes export coefficient model (ECM) by developing a method to determine the export coefficients of different land use types based on the hydrological and water quality data. Taking NPS total nitrogen (TN) and total phosphorus (TP) as the study objects, this study estimated the contributions of different pollution sources and analyzed their spatial distributions based on the improved ECM. The results underlined that the method for obtaining output coefficients of land use types using hydrology and water quality data is feasible and accurate, and is suitable for the study of NPS pollution at large-scale basins. The average output structure of NPS TN from land use, rural breeding and rural life is 33.6, 25.9, and 40.5%, and the NPS TP is 31.6, 43.7, and 24.7%, respectively. Especially, dry land was the main land use source for both NPS TN and TP pollution, with the contributed proportions of 81.3 and 81.8% respectively. The counties of Zaozhuang, Tengzhou, Caoxian, Yuncheng, and Shanxian had higher contribution rates and the counties of Dingtao, Juancheng, and Caoxian had the higher load intensities for both NPS TN and TP pollution. The results of this study allowed for an improvement in the understanding of the pollution source contribution and enabled researchers and planners to focus on the most important sources and regions of NPS pollution.

Providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer

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

Archer, Charles J.; Faraj, Daniel A.; Inglett, Todd A.

Methods, apparatus, and products are disclosed for providing full point-to-point communications among compute nodes of an operational group in a global combining network of a parallel computer, each compute node connected to each adjacent compute node in the global combining network through a link, that include: receiving a network packet in a compute node, the network packet specifying a destination compute node; selecting, in dependence upon the destination compute node, at least one of the links for the compute node along which to forward the network packet toward the destination compute node; and forwarding the network packet along the selectedmore » link to the adjacent compute node connected to the compute node through the selected link.« less

EVALUATING POINT-NONPOINT SOURCE WATER QUALITY TRADING IN A RARITAN RIVER BASIN SUB-WATERSHED

EPA Science Inventory

This project addresses water quality issues in the Raritan River Basin of New Jersey. It will build upon an existing study that determined the technical feasibility of implementing a point-nonpoint source water quality trading program in the Basin. Water quality trading is ...

Response of non-point source pollutant loads to climate change in the Shitoukoumen reservoir catchment.

PubMed

Zhang, Lei; Lu, Wenxi; An, Yonglei; Li, Di; Gong, Lei

2012-01-01

The impacts of climate change on streamflow and non-point source pollutant loads in the Shitoukoumen reservoir catchment are predicted by combining a general circulation model (HadCM3) with the Soil and Water Assessment Tool (SWAT) hydrological model. A statistical downscaling model was used to generate future local scenarios of meteorological variables such as temperature and precipitation. Then, the downscaled meteorological variables were used as input to the SWAT hydrological model calibrated and validated with observations, and the corresponding changes of future streamflow and non-point source pollutant loads in Shitoukoumen reservoir catchment were simulated and analyzed. Results show that daily temperature increases in three future periods (2010-2039, 2040-2069, and 2070-2099) relative to a baseline of 1961-1990, and the rate of increase is 0.63°C per decade. Annual precipitation also shows an apparent increase of 11 mm per decade. The calibration and validation results showed that the SWAT model was able to simulate well the streamflow and non-point source pollutant loads, with a coefficient of determination of 0.7 and a Nash-Sutcliffe efficiency of about 0.7 for both the calibration and validation periods. The future climate change has a significant impact on streamflow and non-point source pollutant loads. The annual streamflow shows a fluctuating upward trend from 2010 to 2099, with an increase rate of 1.1 m(3) s(-1) per decade, and a significant upward trend in summer, with an increase rate of 1.32 m(3) s(-1) per decade. The increase in summer contributes the most to the increase of annual load compared with other seasons. The annual NH (4) (+) -N load into Shitoukoumen reservoir shows a significant downward trend with a decrease rate of 40.6 t per decade. The annual TP load shows an insignificant increasing trend, and its change rate is 3.77 t per decade. The results of this analysis provide a scientific basis for effective support of decision

NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

NASA Technical Reports Server (NTRS)

Hong, Jaesub; Mori, Kaya; Hailey, Charles J.; Nynka, Melania; Zhang, Shou; Gotthelf, Eric; Fornasini, Francesca M.; Krivonos, Roman; Bauer, Franz; Perez, Kerstin;

Comparing stochastic point-source and finite-source ground-motion simulations: SMSIM and EXSIM

USGS Publications Warehouse

Boore, D.M.

2009-01-01

Comparisons of ground motions from two widely used point-source and finite-source ground-motion simulation programs (SMSIM and EXSIM) show that the following simple modifications in EXSIM will produce agreement in the motions from a small earthquake at a large distance for the two programs: (1) base the scaling of high frequencies on the integral of the squared Fourier acceleration spectrum; (2) do not truncate the time series from each subfault; (3) use the inverse of the subfault corner frequency for the duration of motions from each subfault; and (4) use a filter function to boost spectral amplitudes at frequencies near and less than the subfault corner frequencies. In addition, for SMSIM an effective distance is defined that accounts for geometrical spreading and anelastic attenuation from various parts of a finite fault. With these modifications, the Fourier and response spectra from SMSIM and EXSIM are similar to one another, even close to a large earthquake (M 7), when the motions are averaged over a random distribution of hypocenters. The modifications to EXSIM remove most of the differences in the Fourier spectra from simulations using pulsing and static subfaults; they also essentially eliminate any dependence of the EXSIM simulations on the number of subfaults. Simulations with the revised programs suggest that the results of Atkinson and Boore (2006), computed using an average stress parameter of 140 bars and the original version of EXSIM, are consistent with the revised EXSIM with a stress parameter near 250 bars.

Power-Law Template for IR Point Source Clustering

NASA Technical Reports Server (NTRS)

Addison, Graeme E.; Dunkley, Joanna; Hajian, Amir; Viero, Marco; Bond, J. Richard; Das, Sudeep; Devlin, Mark; Halpern, Mark; Hincks, Adam; Hlozek, Renee;

Power-Law Template for Infrared Point-Source Clustering

NASA Technical Reports Server (NTRS)

Addison, Graeme E; Dunkley, Joanna; Hajian, Amir; Viero, Marco; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Halpern, Mark; Hincks, Adam D; Hlozek, Renee;

1SXPS: A Deep Swift X-Ray Telescope Point Source Catalog with Light Curves and Spectra

NASA Technical Reports Server (NTRS)

Evans, P. A.; Osborne, J. P.; Beardmore, A. P.; Page, K. L.; Willingale, R.; Mountford, C. J.; Pagani, C.; Burrows, D. N.; Kennea, J. A.; Perri, M.;

VizieR Online Data Catalog: M31 center emission-line point-like sources (Martin+, 2018)

NASA Astrophysics Data System (ADS)

Martin, T. B.; Drissen, L.; Melchior, A.-L.

2017-11-01

We present a catalogue of the point-like sources in the central 11'x11' part of M31 obtained with SITELLE. For each source we report the radial velocity as long as the spectrophotmetric flux of H-alpha, [NII]6584 and the sum of the [SII]6717,6731 doublet. The ID of the sources cross-matched with the catalogues from Merrett et al. (2006MNRAS.369..120M, J/MNRAS/369/120) and Halliday et al. (2006MNRAS.369...97H, J/MNRAS/369/97) are also indicated. We also report the detection of the sources in the images of the Local Group Galaxies Survey (Massey et al., 2006, 2006AJ....131.2478M). (1 data file).

An Improved Statistical Point-source Foreground Model for the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Murray, S. G.; Trott, C. M.; Jordan, C. H.

2017-08-01

We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions for the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.

Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation.

PubMed

Wang, Chong

2018-03-01

In the case of a point source in front of a panel, the wavefront of the incident wave is spherical. This paper discusses spherical sound waves transmitting through a finite sized panel. The forced sound transmission performance that predominates in the frequency range below the coincidence frequency is the focus. Given the point source located along the centerline of the panel, forced sound transmission coefficient is derived through introducing the sound radiation impedance for spherical incident waves. It is found that in addition to the panel mass, forced sound transmission loss also depends on the distance from the source to the panel as determined by the radiation impedance. Unlike the case of plane incident waves, sound transmission performance of a finite sized panel does not necessarily converge to that of an infinite panel, especially when the source is away from the panel. For practical applications, the normal incidence sound transmission loss expression of plane incident waves can be used if the distance between the source and panel d and the panel surface area S satisfy d/S>0.5. When d/S ≈0.1, the diffuse field sound transmission loss expression may be a good approximation. An empirical expression for d/S=0  is also given.

47 CFR 101.1421 - Coordination of adjacent area MVDDS stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multichannel Video Distribution and Data Service Rules for... compatible with adjacent and co-channel operations in the adjacent areas on all its frequencies; and (2... adjacent and co-channel operations in adjacent areas. (b) Harmful interference to public safety stations...

[Nitrogen non-point source pollution identification based on ArcSWAT in Changle River].

PubMed

Deng, Ou-Ping; Sun, Si-Yang; Lü, Jun

2013-04-01

The ArcSWAT (Soil and Water Assessment Tool) model was adopted for Non-point source (NPS) nitrogen pollution modeling and nitrogen source apportionment for the Changle River watershed, a typical agricultural watershed in Southeast China. Water quality and hydrological parameters were monitored, and the watershed natural conditions (including soil, climate, land use, etc) and pollution sources information were also investigated and collected for SWAT database. The ArcSWAT model was established in the Changle River after the calibrating and validating procedures of the model parameters. Based on the validated SWAT model, the contributions of different nitrogen sources to river TN loading were quantified, and spatial-temporal distributions of NPS nitrogen export to rivers were addressed. The results showed that in the Changle River watershed, Nitrogen fertilizer, nitrogen air deposition and nitrogen soil pool were the prominent pollution sources, which contributed 35%, 32% and 25% to the river TN loading, respectively. There were spatial-temporal variations in the critical sources for NPS TN export to the river. Natural sources, such as soil nitrogen pool and atmospheric nitrogen deposition, should be targeted as the critical sources for river TN pollution during the rainy seasons. Chemical nitrogen fertilizer application should be targeted as the critical sources for river TN pollution during the crop growing season. Chemical nitrogen fertilizer application, soil nitrogen pool and atmospheric nitrogen deposition were the main sources for TN exported from the garden plot, forest and residential land, respectively. However, they were the main sources for TN exported both from the upland and paddy field. These results revealed that NPS pollution controlling rules should focus on the spatio-temporal distribution of NPS pollution sources.

Independent evaluation of point source fossil fuel CO2 emissions to better than 10%

PubMed Central

Turnbull, Jocelyn Christine; Keller, Elizabeth D.; Norris, Margaret W.; Wiltshire, Rachael M.

2016-01-01

Independent estimates of fossil fuel CO2 (CO2ff) emissions are key to ensuring that emission reductions and regulations are effective and provide needed transparency and trust. Point source emissions are a key target because a small number of power plants represent a large portion of total global emissions. Currently, emission rates are known only from self-reported data. Atmospheric observations have the potential to meet the need for independent evaluation, but useful results from this method have been elusive, due to challenges in distinguishing CO2ff emissions from the large and varying CO2 background and in relating atmospheric observations to emission flux rates with high accuracy. Here we use time-integrated observations of the radiocarbon content of CO2 (14CO2) to quantify the recently added CO2ff mole fraction at surface sites surrounding a point source. We demonstrate that both fast-growing plant material (grass) and CO2 collected by absorption into sodium hydroxide solution provide excellent time-integrated records of atmospheric 14CO2. These time-integrated samples allow us to evaluate emissions over a period of days to weeks with only a modest number of measurements. Applying the same time integration in an atmospheric transport model eliminates the need to resolve highly variable short-term turbulence. Together these techniques allow us to independently evaluate point source CO2ff emission rates from atmospheric observations with uncertainties of better than 10%. This uncertainty represents an improvement by a factor of 2 over current bottom-up inventory estimates and previous atmospheric observation estimates and allows reliable independent evaluation of emissions. PMID:27573818

Independent evaluation of point source fossil fuel CO2 emissions to better than 10%.

PubMed

Turnbull, Jocelyn Christine; Keller, Elizabeth D; Norris, Margaret W; Wiltshire, Rachael M

2016-09-13

Independent estimates of fossil fuel CO2 (CO2ff) emissions are key to ensuring that emission reductions and regulations are effective and provide needed transparency and trust. Point source emissions are a key target because a small number of power plants represent a large portion of total global emissions. Currently, emission rates are known only from self-reported data. Atmospheric observations have the potential to meet the need for independent evaluation, but useful results from this method have been elusive, due to challenges in distinguishing CO2ff emissions from the large and varying CO2 background and in relating atmospheric observations to emission flux rates with high accuracy. Here we use time-integrated observations of the radiocarbon content of CO2 ((14)CO2) to quantify the recently added CO2ff mole fraction at surface sites surrounding a point source. We demonstrate that both fast-growing plant material (grass) and CO2 collected by absorption into sodium hydroxide solution provide excellent time-integrated records of atmospheric (14)CO2 These time-integrated samples allow us to evaluate emissions over a period of days to weeks with only a modest number of measurements. Applying the same time integration in an atmospheric transport model eliminates the need to resolve highly variable short-term turbulence. Together these techniques allow us to independently evaluate point source CO2ff emission rates from atmospheric observations with uncertainties of better than 10%. This uncertainty represents an improvement by a factor of 2 over current bottom-up inventory estimates and previous atmospheric observation estimates and allows reliable independent evaluation of emissions.

Assessment of Groundwater Susceptibility to Non-Point Source Contaminants Using Three-Dimensional Transient Indexes.

PubMed

Zhang, Yong; Weissmann, Gary S; Fogg, Graham E; Lu, Bingqing; Sun, HongGuang; Zheng, Chunmiao

2018-06-05

Groundwater susceptibility to non-point source contamination is typically quantified by stable indexes, while groundwater quality evolution (or deterioration globally) can be a long-term process that may last for decades and exhibit strong temporal variations. This study proposes a three-dimensional (3- d ), transient index map built upon physical models to characterize the complete temporal evolution of deep aquifer susceptibility. For illustration purposes, the previous travel time probability density (BTTPD) approach is extended to assess the 3- d deep groundwater susceptibility to non-point source contamination within a sequence stratigraphic framework observed in the Kings River fluvial fan (KRFF) aquifer. The BTTPD, which represents complete age distributions underlying a single groundwater sample in a regional-scale aquifer, is used as a quantitative, transient measure of aquifer susceptibility. The resultant 3- d imaging of susceptibility using the simulated BTTPDs in KRFF reveals the strong influence of regional-scale heterogeneity on susceptibility. The regional-scale incised-valley fill deposits increase the susceptibility of aquifers by enhancing rapid downward solute movement and displaying relatively narrow and young age distributions. In contrast, the regional-scale sequence-boundary paleosols within the open-fan deposits "protect" deep aquifers by slowing downward solute movement and displaying a relatively broad and old age distribution. Further comparison of the simulated susceptibility index maps to known contaminant distributions shows that these maps are generally consistent with the high concentration and quick evolution of 1,2-dibromo-3-chloropropane (DBCP) in groundwater around the incised-valley fill since the 1970s'. This application demonstrates that the BTTPDs can be used as quantitative and transient measures of deep aquifer susceptibility to non-point source contamination.

Genetic organization of the unc-22 IV gene and the adjacent region in Caenorhabditis elegans.

PubMed

Rogalski, T M; Baillie, D L

1985-01-01

The genetic organization of the region immediately adjacent to the unc-22 IV gene in Caenorhabditis elegans has been studied. We have identified twenty essential genes in this interval of approximately 1.5-map units on Linkage Group IV. The mutations that define these genes were positioned by recombination mapping and complementation with several deficiencies. With few exceptions, the positions obtained by these two methods agreed. Eight of the twenty essential genes identified are represented by more than one allele. Three possible internal deletions of the unc-22 gene have been located by intra-genic mapping. In addition, the right end point of a deficiency or an inversion affecting the adjacent genes let-56 and unc-22 has been positioned inside the unc-22 gene.

OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens

NASA Astrophysics Data System (ADS)

Yoo, Jaiyul; DePoy, D. L.; Gal-Yam, A.; Gaudi, B. S.; Gould, A.; Han, C.; Lipkin, Y.; Maoz, D.; Ofek, E. O.; Park, B.-G.; Pogge, R. W.; Mu-Fun Collaboration; Udalski, A.; Soszyński, I.; Wyrzykowski, Ł.; Kubiak, M.; Szymański, M.; Pietrzyński, G.; Szewczyk, O.; Żebruń, K.; OGLE Collaboration

2004-03-01

We analyze OGLE-2003-BLG-262, a relatively short (tE=12.5+/-0.1 day) microlensing event generated by a point-mass lens transiting the face of a K giant source in the Galactic bulge. We use the resulting finite-source effects to measure the angular Einstein radius, θE=195+/-17 μas, and so constrain the lens mass to the FWHM interval 0.08source relative proper motion is μrel=27+/-2 km s-1 kpc-1. Both values are typical of what is expected for lenses detected toward the bulge. Despite the short duration of the event, we detect marginal evidence for a ``parallax asymmetry'' but argue that this is more likely to be induced by acceleration of the source, a binary lens, or possibly by statistical fluctuations. Although OGLE-2003-BLG-262 is only the second published event to date in which the lens transits the source, such events will become more common with the new OGLE-III survey in place. We therefore give a detailed account of the analysis of this event to facilitate the study of future events of this type. Based in part on observations obtained with the 1.3 m Warsaw Telescope at the Las Campanas Observatory of the Carnegie Institution of Washington.

A point-source outbreak of Coccidioidomycosis among a highway construction crew.

PubMed

Nicas, Mark

2018-01-01

Coccidioidomycosis is an infection caused by inhaling spores of the soil fungus Coccidioides immitis (hereafter termed Cocci). Cocci is endemic in certain areas of California. When soil containing the fungus is disturbed, as during earth-moving activities, respirable Cocci spores can become airborne and be inhaled by persons in the vicinity. This article describes a cluster of seven Cocciodioidomycosis cases among a highway construction crew that occurred in June/July 2008 in Kern County, CA, which is among the most highly endemic regions for Cocci in California. The exposures spanned no more than seven work days, and illness developed within two to three weeks of the exposures. Given the common source of exposure (soil dust generated at the work site) and the multiple cases occurring close in time, the cluster can also be termed a "point-source outbreak." The contractor was not informed of the infection risk and did not take adequate precautions against dust exposure. Appropriate engineering/administrative controls and respiratory protection are discussed.

Quantum coordinated multi-point communication based on entanglement swapping

NASA Astrophysics Data System (ADS)

Du, Gang; Shang, Tao; Liu, Jian-wei

2017-05-01

In a quantum network, adjacent nodes can communicate with each other point to point by using pre-shared Einsten-Podolsky-Rosen (EPR) pairs, and furthermore remote nodes can establish entanglement channels by using quantum routing among intermediate nodes. However, with the rapid development of quantum networks, the demand of various message transmission among nodes inevitably emerges. In order to realize this goal and extend quantum networks, we propose a quantum coordinated multi-point communication scheme based on entanglement swapping. The scheme takes full advantage of EPR pairs between adjacent nodes and performs multi-party entanglement swapping to transmit messages. Considering various demands of communication, all nodes work cooperatively to realize different message transmission modes, including one to many, many to one and one to some. Scheme analysis shows that the proposed scheme can flexibly organize a coordinated group and efficiently use EPR resources, while it meets basic security requirement under the condition of coordinated communication.

High frequency seismic signal generated by landslides on complex topographies: from point source to spatially distributed sources

NASA Astrophysics Data System (ADS)

Mangeney, A.; Kuehnert, J.; Capdeville, Y.; Durand, V.; Stutzmann, E.; Kone, E. H.; Sethi, S.

2017-12-01

During their flow along the topography, landslides generate seismic waves in a wide frequency range. These so called landquakes can be recorded at very large distances (a few hundreds of km for large landslides). The recorded signals depend on the landslide seismic source and the seismic wave propagation. If the wave propagation is well understood, the seismic signals can be inverted for the seismic source and thus can be used to get information on the landslide properties and dynamics. Analysis and modeling of long period seismic signals (10-150s) have helped in this way to discriminate between different landslide scenarios and to constrain rheological parameters (e.g. Favreau et al., 2010). This was possible as topography poorly affects wave propagation at these long periods and the landslide seismic source can be approximated as a point source. In the near-field and at higher frequencies (> 1 Hz) the spatial extent of the source has to be taken into account and the influence of the topography on the recorded seismic signal should be quantified in order to extract information on the landslide properties and dynamics. The characteristic signature of distributed sources and varying topographies is studied as a function of frequency and recording distance.The time dependent spatial distribution of the forces applied to the ground by the landslide are obtained using granular flow numerical modeling on 3D topography. The generated seismic waves are simulated using the spectral element method. The simulated seismic signal is compared to observed seismic data from rockfalls at the Dolomieu Crater of Piton de la Fournaise (La Réunion).Favreau, P., Mangeney, A., Lucas, A., Crosta, G., and Bouchut, F. (2010). Numerical modeling of landquakes. Geophysical Research Letters, 37(15):1-5.

Robust point cloud classification based on multi-level semantic relationships for urban scenes

NASA Astrophysics Data System (ADS)

Zhu, Qing; Li, Yuan; Hu, Han; Wu, Bo

2017-07-01

The semantic classification of point clouds is a fundamental part of three-dimensional urban reconstruction. For datasets with high spatial resolution but significantly more noises, a general trend is to exploit more contexture information to surmount the decrease of discrimination of features for classification. However, previous works on adoption of contexture information are either too restrictive or only in a small region and in this paper, we propose a point cloud classification method based on multi-level semantic relationships, including point-homogeneity, supervoxel-adjacency and class-knowledge constraints, which is more versatile and incrementally propagate the classification cues from individual points to the object level and formulate them as a graphical model. The point-homogeneity constraint clusters points with similar geometric and radiometric properties into regular-shaped supervoxels that correspond to the vertices in the graphical model. The supervoxel-adjacency constraint contributes to the pairwise interactions by providing explicit adjacent relationships between supervoxels. The class-knowledge constraint operates at the object level based on semantic rules, guaranteeing the classification correctness of supervoxel clusters at that level. International Society of Photogrammetry and Remote Sensing (ISPRS) benchmark tests have shown that the proposed method achieves state-of-the-art performance with an average per-area completeness and correctness of 93.88% and 95.78%, respectively. The evaluation of classification of photogrammetric point clouds and DSM generated from aerial imagery confirms the method's reliability in several challenging urban scenes.

Identification of 'Point A' as the prevalent source of error in cephalometric analysis of lateral radiographs.

PubMed

Grogger, P; Sacher, C; Weber, S; Millesi, G; Seemann, R

2018-04-10

Deviations in measuring dentofacial components in a lateral X-ray represent a major hurdle in the subsequent treatment of dysgnathic patients. In a retrospective study, we investigated the most prevalent source of error in the following commonly used cephalometric measurements: the angles Sella-Nasion-Point A (SNA), Sella-Nasion-Point B (SNB) and Point A-Nasion-Point B (ANB); the Wits appraisal; the anteroposterior dysplasia indicator (APDI); and the overbite depth indicator (ODI). Preoperative lateral radiographic images of patients with dentofacial deformities were collected and the landmarks digitally traced by three independent raters. Cephalometric analysis was automatically performed based on 1116 tracings. Error analysis identified the x-coordinate of Point A as the prevalent source of error in all investigated measurements, except SNB, in which it is not incorporated. In SNB, the y-coordinate of Nasion predominated error variance. SNB showed lowest inter-rater variation. In addition, our observations confirmed previous studies showing that landmark identification variance follows characteristic error envelopes in the highest number of tracings analysed up to now. Variance orthogonal to defining planes was of relevance, while variance parallel to planes was not. Taking these findings into account, orthognathic surgeons as well as orthodontists would be able to perform cephalometry more accurately and accomplish better therapeutic results. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

A Targeted Search for Point Sources of EeV Photons with the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Aab, A.; Abreu, P.; Aglietta, M.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Anastasi, G. A.; Anchordoqui, L.; Andrada, B.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Badescu, A. M.; Balaceanu, A.; Barreira Luz, R. J.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Biteau, J.; Blaess, S. G.; Blanco, A.; Blazek, J.; Bleve, C.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Botti, A. M.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, L.; Cancio, A.; Canfora, F.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Chavez, A. G.; Chinellato, J. A.; Chudoba, J.; Clay, R. W.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Cronin, J.; D'Amico, S.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; Debatin, J.; Deligny, O.; Di Giulio, C.; Di Matteo, A.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; D'Olivo, J. C.; Dorosti, Q.; dos Anjos, R. C.; Dova, M. T.; Dundovic, A.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Fick, B.; Figueira, J. M.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Fuster, A.; Gaior, R.; García, B.; Garcia-Pinto, D.; Gaté, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gorgi, A.; Gorham, P.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kemp, J.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A.; LaHurd, D.; Lauscher, M.; Legumina, R.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Luce, Q.; Lucero, A.; Malacari, M.; Mallamaci, M.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melo, D.; Menshikov, A.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Mockler, D.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Müller, A. L.; Müller, G.; Muller, M. A.; Müller, S.; Mussa, R.; Naranjo, I.; Nellen, L.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, H.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Pereira, L. A. S.; Perlín, M.; Perrone, L.; Peters, C.; Petrera, S.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Ramos-Pollan, R.; Rautenberg, J.; Ravignani, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rogozin, D.; Roncoroni, M. J.; Roth, M.; Roulet, E.; Rovero, A. C.; Ruehl, P.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarmento, R.; Sarmiento, C. A.; Sato, R.; Schauer, M.; Scherini, V.; Schieler, H.; Schimp, M.; Schmidt, D.; Scholten, O.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Strafella, F.; Suarez, F.; Suarez Durán, M.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A. D.; Swain, J.; Szadkowski, Z.; Taboada, A.; Taborda, O. A.; Tapia, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Tomankova, L.; Tomé, B.; Torralba Elipe, G.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Villaseñor, L.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yang, L.; Yelos, D.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zong, Z.; Zuccarello, F.

2017-03-01

Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined p-values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. These limits significantly constrain predictions of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.

Relative importance of wastewater treatment plants and non-point sources of perfluorinated compounds to Washington State rivers.

PubMed

Furl, Chad V; Meredith, Callie A; Strynar, Mark J; Nakayama, Shoji F

2011-07-01

Perfluorinated compounds (PFCs) were measured in 10 Washington State rivers and 4 wastewater treatment plants (WWTPs) under periods of low and high flows to investigate the relative importance of point and non-point sources to rivers. PFCs were detected in all samples with summed values ranging from 1.11 to 74.9 ng/L in surface waters and 62.3-418 ng/L in WWTP effluent. Concentrations in 6 of the 10 rivers exhibited a positive relationship with flow, indicating runoff as a contributing source, with PFC loads greatest at all 10 waterbodies during high flows. Perfluoroheptanoic acid:perfluorooctanoic acid homologue ratios suggest atmospheric contributions to the waterbodies are important throughout the year. Principal component analysis (PCA) indicated distinct homologue profiles for high flow, low flow, and effluent samples. The PCA demonstrates that during the spring when flows and loads are at their greatest; WWTP discharges are not the primary sources of PFCs to the river systems. Taken together, the evidence provided signifies non-point inputs are a major pathway for PFCs to surface waters in Washington State. Copyright © 2011 Elsevier B.V. All rights reserved.

40 CFR Table 4 to Part 455 - BAT and NSPS Effluent Limitations for Priority Pollutants for Direct Discharge Point Sources That...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false BAT and NSPS Effluent Limitations for Priority Pollutants for Direct Discharge Point Sources That use End-of-Pipe Biological Treatment 4 Table 4... Limitations for Priority Pollutants for Direct Discharge Point Sources That use End-of-Pipe Biological...

Methane Flux Estimation from Point Sources using GOSAT Target Observation: Detection Limit and Improvements with Next Generation Instruments

NASA Astrophysics Data System (ADS)

Kuze, A.; Suto, H.; Kataoka, F.; Shiomi, K.; Kondo, Y.; Crisp, D.; Butz, A.

2017-12-01

Atmospheric methane (CH4) has an important role in global radiative forcing of climate but its emission estimates have larger uncertainties than carbon dioxide (CO2). The area of anthropogenic emission sources is usually much smaller than 100 km2. The Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT) has measured CO2 and CH4 column density using sun light reflected from the earth's surface. It has an agile pointing system and its footprint can cover 87-km2 with a single detector. By specifying pointing angles and observation time for every orbit, TANSO-FTS can target various CH4 point sources together with reference points every 3 day over years. We selected a reference point that represents CH4 background density before or after targeting a point source. By combining satellite-measured enhancement of the CH4 column density and surface measured wind data or estimates from the Weather Research and Forecasting (WRF) model, we estimated CH4emission amounts. Here, we picked up two sites in the US West Coast, where clear sky frequency is high and a series of data are available. The natural gas leak at Aliso Canyon showed a large enhancement and its decrease with time since the initial blowout. We present time series of flux estimation assuming the source is single point without influx. The observation of the cattle feedlot in Chino, California has weather station within the TANSO-FTS footprint. The wind speed is monitored continuously and the wind direction is stable at the time of GOSAT overpass. The large TANSO-FTS footprint and strong wind decreases enhancement below noise level. Weak wind shows enhancements in CH4, but the velocity data have large uncertainties. We show the detection limit of single samples and how to reduce uncertainty using time series of satellite data. We will propose that the next generation instruments for accurate anthropogenic CO2 and CH

DISCRIMINATION OF NATURAL AND NON-POINT SOURCE EFFECTS FROM ANTHROGENIC EFFECTS AS REFLECTED IN BENTHIC STATE IN THREE ESTUARIES IN NEW ENGLAND

EPA Science Inventory

In order to protect estuarine resources, managers must be able to discern the effects of natural conditions and non-point source effects, and separate them from multiple anthropogenic point source effects. Our approach was to evaluate benthic community assemblages, riverine nitro...

33 CFR 80.1395 - Puget Sound and adjacent waters.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

33 CFR 80.1395 - Puget Sound and adjacent waters.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

33 CFR 80.1395 - Puget Sound and adjacent waters.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

33 CFR 80.1395 - Puget Sound and adjacent waters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

33 CFR 80.1395 - Puget Sound and adjacent waters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

Cryopreserved embryo transfer: adjacent or non-adjacent to failed fresh long GnRH-agonist protocol IVF cycle.

PubMed

Volodarsky-Perel, Alexander; Eldar-Geva, Talia; Holzer, Hananel E G; Schonberger, Oshrat; Reichman, Orna; Gal, Michael

2017-03-01

The optimal time to perform cryopreserved embryo transfer (CET) after a failed oocyte retrieval-embryo transfer (OR-ET) cycle is unknown. Similar clinical pregnancy rates were recently reported in immediate and delayed CET, performed after failed fresh OR-ET, in cycles with the gonadotrophin-releasing hormone (GnRH) antagonist protocol. This study compared outcomes of CET performed adjacently (<50 days, n = 67) and non-adjacently (≥50 to 120 days, n = 62) to the last OR-day of cycles with the GnRH agonist down-regulation protocol. Additional inclusion criteria were patients' age 20-38 years, the transfer of only 1-2 cryopreserved embryos, one treatment cycle per patient and artificial preparation for CET. Significantly higher implantation, clinical pregnancy and live birth rates were found in the non-adjacent group than in the adjacent group: 30.5% versus 11.3% (P = 0.001), 41.9% versus 17.9% (P = 0.003) and 32.3% versus 13.4% (P = 0.01), respectively. These results support the postponement of CET after a failed OR-ET for at least one menstrual cycle, when a preceding long GnRH-agonist protocol is used. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Stress Wave Interaction Between Two Adjacent Blast Holes

NASA Astrophysics Data System (ADS)

Yi, Changping; Johansson, Daniel; Nyberg, Ulf; Beyglou, Ali

2016-05-01

Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

A new false color composite technique for dust enhancement and point source determination in Middle East

NASA Astrophysics Data System (ADS)

Karimi, Khadijeh; Taheri Shahraiyni, Hamid; Habibi Nokhandan, Majid; Hafezi Moghaddas, Naser; Sanaeifar, Melika

2011-11-01

The dust storm happens in the Middle East with very high frequency. According to the dust storm effects, it is vital to study on the dust storms in the Middle East. The first step toward the study on dust storm is the enhancement of dust storms and determination of the point sources. In this paper, a new false color composite (FCC) map for the dust storm enhancement and point sources determination in the Middle East has been developed. The 28 Terra-MODIS images in 2008 and 2009 were utilized in this study. We tried to replace the Red, Green and Blue bands in RGB maps with the bands or maps that enhance the dust storms. Hence, famous indices for dust storm detection (NDDI, D and BTD) were generated using the different bands of MODIS images. These indices with some bands of MODIS were utilized for FCC map generation with different combinations. Among the different combinations, four better FCC maps were selected and these four FCC are compared using visual interpretation. The results of visual interpretations showed that the best FCC map for enhancement of dust storm in the middle east is an especial combination of the three indices (Red: D, Green: BTD and Blue: NDDI). Therefore, we utilized of this new FCC method for the enhancement of dust storms and determination of point sources in Middle East.

A Northern Sky Survey for Point-like Sources of EeV Neutral Particles with the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2015-05-01

We report on the search for steady point-like sources of neutral particles around 1018 eV between 2008 and 2013 May with the scintillator SD of the Telescope Array experiment. We found overall no significant point-like excess above 0.5 EeV in the northern sky. Subsequently, we also searched for coincidence with the Fermi bright Galactic sources. No significant coincidence was found within the statistical uncertainty. Hence, we set an upper limit on the neutron flux that corresponds to an averaged flux of 0.07 km-2 yr-1 for E\\gt 1 EeV in the northern sky at the 95% confidence level. This is the most stringent flux upper limit in a northern sky survey assuming point-like sources. The upper limit at the 95% confidence level on the neutron flux from Cygnus X-3 is also set to 0.2 km-2 yr-1 for E\\gt 0.5 EeV. This is an order of magnitude lower than previous flux measurements.

CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES: THE SOURCE CATALOG

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

Wang, Song; Liu, Jifeng; Qiu, Yanli

The Chandra archival data is a valuable resource for various studies on different X-ray astronomy topics. In this paper, we utilize this wealth of information and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 Advanced CCD Imaging Spectrometer observations, which produces 363,530 source detections belonging to 217,828 distinct X-ray sources. This number is twice the size of the Chandra Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors,more » fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows that 17,828 sources are located within the D {sub 25} isophotes of 1110 galaxies, and 7504 sources are located between the D {sub 25} and 2 D {sub 25} isophotes of 910 galaxies. Contamination analysis with the log N –log S relation indicates that 51.3% of objects within 2 D {sub 25} isophotes are truly relevant to galaxies, and the “net” source fraction increases to 58.9%, 67.3%, and 69.1% for sources with luminosities above 10{sup 37}, 10{sup 38}, and 10{sup 39} erg s{sup −1}, respectively. Among the possible scientific uses of this catalog, we discuss the possibility of studying intra-observation variability, inter-observation variability, and supersoft sources (SSSs). About 17,092 detected sources above 10 counts are classified as variable in individual observation with the Kolmogorov–Smirnov (K–S) criterion ( P {sub K–S} < 0.01). There are 99,647 sources observed more than once and 11,843 sources observed 10 times or more, offering us a wealth of data with which to explore the long-term variability. There are 1638 individual objects (∼2350 detections) classified as SSSs. As a quite interesting subclass, detailed studies on X-ray spectra and optical spectroscopic follow-up are

A compiled catalog of rotation measures of radio point sources

NASA Astrophysics Data System (ADS)

Xu, Jun; Han, Jin-Lin

2014-08-01

We compiled a catalog of Faraday rotation measures (RMs) for 4553 extragalactic radio point sources published in literature. These RMs were derived from multi-frequency polarization observations. The RM data are compared to those in the NRAO VLA Sky Survey (NVSS) RM catalog. We reveal a systematic uncertainty of about 10.0 ± 1.5 rad m-2 in the NVSS RM catalog. The Galactic foreground RM is calculated through a weighted averaging method by using the compiled RM catalog together with the NVSS RM catalog, with careful consideration of uncertainties in the RM data. The data from the catalog and the interface for the Galactic foreground RM calculations are publicly available on the webpage: http://zmtt.bao.ac.cn/RM/.

Discretized energy minimization in a wave guide with point sources

NASA Technical Reports Server (NTRS)

Propst, G.

1994-01-01

An anti-noise problem on a finite time interval is solved by minimization of a quadratic functional on the Hilbert space of square integrable controls. To this end, the one-dimensional wave equation with point sources and pointwise reflecting boundary conditions is decomposed into a system for the two propagating components of waves. Wellposedness of this system is proved for a class of data that includes piecewise linear initial conditions and piecewise constant forcing functions. It is shown that for such data the optimal piecewise constant control is the solution of a sparse linear system. Methods for its computational treatment are presented as well as examples of their applicability. The convergence of discrete approximations to the general optimization problem is demonstrated by finite element methods.

Comparison of Point Cloud Registration Algorithms for Better Result Assessment - Towards AN Open-Source Solution

NASA Astrophysics Data System (ADS)

Lachat, E.; Landes, T.; Grussenmeyer, P.

2018-05-01

Terrestrial and airborne laser scanning, photogrammetry and more generally 3D recording techniques are used in a wide range of applications. After recording several individual 3D datasets known in local systems, one of the first crucial processing steps is the registration of these data into a common reference frame. To perform such a 3D transformation, commercial and open source software as well as programs from the academic community are available. Due to some lacks in terms of computation transparency and quality assessment in these solutions, it has been decided to develop an open source algorithm which is presented in this paper. It is dedicated to the simultaneous registration of multiple point clouds as well as their georeferencing. The idea is to use this algorithm as a start point for further implementations, involving the possibility of combining 3D data from different sources. Parallel to the presentation of the global registration methodology which has been employed, the aim of this paper is to confront the results achieved this way with the above-mentioned existing solutions. For this purpose, first results obtained with the proposed algorithm to perform the global registration of ten laser scanning point clouds are presented. An analysis of the quality criteria delivered by two selected software used in this study and a reflexion about these criteria is also performed to complete the comparison of the obtained results. The final aim of this paper is to validate the current efficiency of the proposed method through these comparisons.

Measurements of scalar released from point sources in a turbulent boundary layer

NASA Astrophysics Data System (ADS)

Talluru, K. M.; Hernandez-Silva, C.; Philip, J.; Chauhan, K. A.

2017-04-01

Measurements of velocity and concentration fluctuations for a horizontal plume released at several wall-normal locations in a turbulent boundary layer (TBL) are discussed in this paper. The primary objective of this study is to establish a systematic procedure to acquire accurate single-point concentration measurements for a substantially long time so as to obtain converged statistics of long tails of probability density functions of concentration. Details of the calibration procedure implemented for long measurements are presented, which include sensor drift compensation to eliminate the increase in average background concentration with time. While most previous studies reported measurements where the source height is limited to, {{s}z}/δ ≤slant 0.2 , where s z is the wall-normal source height and δ is the boundary layer thickness, here results of concentration fluctuations when the plume is released in the outer layer are emphasised. Results of mean and root-mean-square (r.m.s.) profiles of concentration for elevated sources agree with the well-accepted reflected Gaussian model (Fackrell and Robins 1982 J. Fluid. Mech. 117). However, there is clear deviation from the reflected Gaussian model for source in the intermittent region of TBL particularly at locations higher than the source itself. Further, we find that the plume half-widths are different for the mean and r.m.s. concentration profiles. Long sampling times enabled us to calculate converged probability density functions at high concentrations and these are found to exhibit exponential distribution.

Development document for proposed effluent-limitations guidelines and standards for shipbuilding and repair. Point-source category

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

Not Available

1979-12-01

The document contains a discussion of the technical rationale for effluent limitations guidelines for the Shipbuilding and Repair Point Source Category, and the control and treatment technologies which form the basis for these guidelines.

A Targeted Search for Point Sources of EeV Photons with the Pierre Auger Observatory

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

Aab, A.; Abreu, P.; Aglietta, M.

Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined p-values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. Lastly, these limits significantly constrain predictionsmore » of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.« less

A Targeted Search for Point Sources of EeV Photons with the Pierre Auger Observatory

DOE PAGES

Aab, A.; Abreu, P.; Aglietta, M.; ...

2017-03-09

Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined p-values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. Lastly, these limits significantly constrain predictionsmore » of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.« less

A Targeted Search for Point Sources of EeV Photons with the Pierre Auger Observatory

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

Aab, A.; Abreu, P.; Aglietta, M.

Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined p -values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. These limits significantly constrain predictionsmore » of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.« less

The Development and Application of Spatiotemporal Metrics for the Characterization of Point Source FFCO2 Emissions and Dispersion

NASA Astrophysics Data System (ADS)

Roten, D.; Hogue, S.; Spell, P.; Marland, E.; Marland, G.

2017-12-01

There is an increasing role for high resolution, CO2 emissions inventories across multiple arenas. The breadth of the applicability of high-resolution data is apparent from their use in atmospheric CO2 modeling, their potential for validation of space-based atmospheric CO2 remote-sensing, and the development of climate change policy. This work focuses on increasing our understanding of the uncertainty in these inventories and the implications on their downstream use. The industrial point sources of emissions (power generating stations, cement manufacturing plants, paper mills, etc.) used in the creation of these inventories often have robust emissions characteristics, beyond just their geographic location. Physical parameters of the emission sources such as number of exhaust stacks, stack heights, stack diameters, exhaust temperatures, and exhaust velocities, as well as temporal variability and climatic influences can be important in characterizing emissions. Emissions from large point sources can behave much differently than emissions from areal sources such as automobiles. For many applications geographic location is not an adequate characterization of emissions. This work demonstrates the sensitivities of atmospheric models to the physical parameters of large point sources and provides a methodology for quantifying parameter impacts at multiple locations across the United States. The sensitivities highlight the importance of location and timing and help to highlight potential aspects that can guide efforts to reduce uncertainty in emissions inventories and increase the utility of the models.

Integrated watershed approach in controlling point and non-point source pollution within Zelivka drinking water reservoir.

PubMed

Holas, J; Hrncir, M

2002-01-01

An agricultural watershed involves manipulation of soil, water and other natural resources and it has profound impacts on ecosystems. To manage these complex issues, we must understand causes and consequences and interactions-related transport of pollutants, quality of the environment, mitigation measures and policy measures. A ten year period of economic changes has been analysed with respect to sustainable development concerning Zelivka drinking water reservoir and its watershed, where agriculture and forestry are the main human activities. It is recommended that all land users within a catchment area should receive payments for their contribution to water cycle management. Setting up the prevention principles and best management practices financially subsidized by a local water company has been found very effective in both point and non-point source pollution abatement, and the newly prepared Clean Water Programme actively involves local municipal authorities as well. The first step based on systems analysis was to propose effective strategies and select alternative measures and ways for their financing. Long term monitoring of nutrient loads entering the reservoir and hazardous events statistics resulted in maps characterising the territory including vulnerable zones and risk factors. Financing involves providing annual payments to farmers, who undertake to manage specified areas of their land in a particular way and one-off payments to realise proposed issues ensuring soil conservation and watershed ecosystem benefits.

Dlx proteins position the neural plate border and determine adjacent cell fates.

PubMed

Woda, Juliana M; Pastagia, Julie; Mercola, Mark; Artinger, Kristin Bruk

2003-01-01

The lateral border of the neural plate is a major source of signals that induce primary neurons, neural crest cells and cranial placodes as well as provide patterning cues to mesodermal structures such as somites and heart. Whereas secreted BMP, FGF and Wnt proteins influence the differentiation of neural and non-neural ectoderm, we show here that members of the Dlx family of transcription factors position the border between neural and non-neural ectoderm and are required for the specification of adjacent cell fates. Inhibition of endogenous Dlx activity in Xenopus embryos with an EnR-Dlx homeodomain fusion protein expands the neural plate into non-neural ectoderm tissue whereas ectopic activation of Dlx target genes inhibits neural plate differentiation. Importantly, the stereotypic pattern of border cell fates in the adjacent ectoderm is re-established only under conditions where the expanded neural plate abuts Dlx-positive non-neural ectoderm. Experiments in which presumptive neural plate was grafted to ventral ectoderm reiterate induction of neural crest and placodal lineages and also demonstrate that Dlx activity is required in non-neural ectoderm for the production of signals needed for induction of these cells. We propose that Dlx proteins regulate intercellular signaling across the interface between neural and non-neural ectoderm that is critical for inducing and patterning adjacent cell fates.

Dlx proteins position the neural plate border and determine adjacent cell fates

PubMed Central

Woda, Juliana M.; Pastagia, Julie; Mercola, Mark; Artinger, Kristin Bruk

2014-01-01

Summary The lateral border of the neural plate is a major source of signals that induce primary neurons, neural crest cells and cranial placodes as well as provide patterning cues to mesodermal structures such as somites and heart. Whereas secreted BMP, FGF and Wnt proteins influence the differentiation of neural and non-neural ectoderm, we show here that members of the Dlx family of transcription factors position the border between neural and non-neural ectoderm and are required for the specification of adjacent cell fates. Inhibition of endogenous Dlx activity in Xenopus embryos with an EnR-Dlx homeodomain fusion protein expands the neural plate into non-neural ectoderm tissue whereas ectopic activation of Dlx target genes inhibits neural plate differentiation. Importantly, the stereotypic pattern of border cell fates in the adjacent ectoderm is re-established only under conditions where the expanded neural plate abuts Dlx-positive non-neural ectoderm. Experiments in which presumptive neural plate was grafted to ventral ectoderm reiterate induction of neural crest and placodal lineages and also demonstrate that Dlx activity is required in non-neural ectoderm for the production of signals needed for induction of these cells. We propose that Dlx proteins regulate intercellular signaling across the interface between neural and non-neural ectoderm that is critical for inducing and patterning adjacent cell fates. PMID:12466200

Contribution of the upper river, the estuarine region, and the adjacent sea to the heavy metal pollution in the Yangtze Estuary.

PubMed

Yin, Su; Wu, Yuehan; Xu, Wei; Li, Yangyang; Shen, Zhenyao; Feng, Chenghong

2016-07-01

To determine whether the discharge control of heavy metals in the Yangtze River basin can significantly change the pollution level in the estuary, this study analyzed the sources (upper river, the estuarine region, and the adjacent sea) of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in dissolved and particulate phases in the surface water of the estuary during wet, normal, and dry seasons. Metal sources inferred from section fluxes agree with those in statistical analysis methods. Heavy metal pollution in the surface water of Yangtze Estuary primarily depends on the sediment suspension and the wastewater discharge from estuary cities. Upper river only constitutes the main source of dissolved heavy metals during the wet season, while the estuarine region and the adjacent sea (especially the former) dominate the dissolved metal pollution in the normal and dry seasons. Particulate metals are mainly derived from sediment suspension in the estuary and the adjacent sea, and the contribution of the upper river can be neglected. Compared with the hydrologic seasons, flood-ebb tides exert a more obvious effect on the water flow directions in the estuary. Sediment suspension, not the upper river, significantly affects the suspended particulate matter concentration in the estuary. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multiple window spatial registration error of a gamma camera: 133Ba point source as a replacement of the NEMA procedure.

PubMed

Bergmann, Helmar; Minear, Gregory; Raith, Maria; Schaffarich, Peter M

2008-12-09

The accuracy of multiple window spatial resolution characterises the performance of a gamma camera for dual isotope imaging. In the present study we investigate an alternative method to the standard NEMA procedure for measuring this performance parameter. A long-lived 133Ba point source with gamma energies close to 67Ga and a single bore lead collimator were used to measure the multiple window spatial registration error. Calculation of the positions of the point source in the images used the NEMA algorithm. The results were validated against the values obtained by the standard NEMA procedure which uses a liquid 67Ga source with collimation. Of the source-collimator configurations under investigation an optimum collimator geometry, consisting of a 5 mm thick lead disk with a diameter of 46 mm and a 5 mm central bore, was selected. The multiple window spatial registration errors obtained by the 133Ba method showed excellent reproducibility (standard deviation < 0.07 mm). The values were compared with the results from the NEMA procedure obtained at the same locations and showed small differences with a correlation coefficient of 0.51 (p < 0.05). In addition, the 133Ba point source method proved to be much easier to use. A Bland-Altman analysis showed that the 133Ba and the 67Ga Method can be used interchangeably. The 133Ba point source method measures the multiple window spatial registration error with essentially the same accuracy as the NEMA-recommended procedure, but is easier and safer to use and has the potential to replace the current standard procedure.

[Urban non-point source pollution control by runoff retention and filtration pilot system].

PubMed

Bai, Yao; Zuo, Jian-E; Gan, Li-Li; Low, Thong Soon; Miao, Heng-Feng; Ruan, Wen-Quan; Huang, Xia

2011-09-01

A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.

Finite Element modelling of deformation induced by interacting volcanic sources

NASA Astrophysics Data System (ADS)

Pascal, Karen; Neuberg, Jürgen; Rivalta, Eleonora

2010-05-01

The displacement field due to magma movements in the subsurface is commonly modelled using the solutions for a point source (Mogi, 1958), a finite spherical source (McTigue, 1987), or a dislocation source (Okada, 1992) embedded in a homogeneous elastic half-space. When the magmatic system comprises more than one source, the assumption of homogeneity in the half-space is violated and several sources are combined, their respective deformation field being summed. We have investigated the effects of neglecting the interaction between sources on the surface deformation field. To do so, we calculated the vertical and horizontal displacements for models with adjacent sources and we tested them against the solutions of corresponding numerical 3D finite element models. We implemented several models combining spherical pressure sources and dislocation sources, varying their relative position. Furthermore we considered the impact of topography, loading, and magma compressibility. To quantify the discrepancies and compare the various models, we calculated the difference between analytical and numerical maximum horizontal or vertical surface displacements.We will demonstrate that for certain conditions combining analytical sources can cause an error of up to 20%. References: McTigue, D. F. (1987), Elastic Stress and Deformation Near a Finite Spherical Magma Body: Resolution of the Point Source Paradox, J. Geophys. Res. 92, 12931-12940. Mogi, K. (1958), Relations between the eruptions of various volcanoes and the deformations of the ground surfaces around them, Bull Earthquake Res Inst, Univ Tokyo 36, 99-134. Okada, Y. (1992), Internal Deformation Due to Shear and Tensile Faults in a Half-Space, Bulletin of the Seismological Society of America 82(2), 1018-1040.

PHOTOCHEMICAL SIMULATIONS OF POINT SOURCE EMISSIONS WITH THE MODELS-3 CMAQ PLUME-IN-GRID APPROACH

EPA Science Inventory

A plume-in-grid (PinG) approach has been designed to provide a realistic treatment for the simulation the dynamic and chemical processes impacting pollutant species in major point source plumes during a subgrid scale phase within an Eulerian grid modeling framework. The PinG sci...

Self-force on a point charge and linear source in the space of a screw dislocation

NASA Astrophysics Data System (ADS)

Azevedo, Sérgio; Moraes, Fernando

2000-03-01

Using a description of defect in solids in terms of three-dimensional gravity, we determine the eletrostatic self-force acting on a point teste charge and a linear source in the presence of a screw dislocation.

Launching and controlling Gaussian beams from point sources via planar transformation media

NASA Astrophysics Data System (ADS)

Odabasi, Hayrettin; Sainath, Kamalesh; Teixeira, Fernando L.

2018-02-01

Based on operations prescribed under the paradigm of complex transformation optics (CTO) [F. Teixeira and W. Chew, J. Electromagn. Waves Appl. 13, 665 (1999), 10.1163/156939399X01104; F. L. Teixeira and W. C. Chew, Int. J. Numer. Model. 13, 441 (2000), 10.1002/1099-1204(200009/10)13:5%3C441::AID-JNM376%3E3.0.CO;2-J; H. Odabasi, F. L. Teixeira, and W. C. Chew, J. Opt. Soc. Am. B 28, 1317 (2011), 10.1364/JOSAB.28.001317; B.-I. Popa and S. A. Cummer, Phys. Rev. A 84, 063837 (2011), 10.1103/PhysRevA.84.063837], it was recently shown in [G. Castaldi, S. Savoia, V. Galdi, A. Alù, and N. Engheta, Phys. Rev. Lett. 110, 173901 (2013), 10.1103/PhysRevLett.110.173901] that a complex source point (CSP) can be mimicked by parity-time (PT ) transformation media. Such coordinate transformation has a mirror symmetry for the imaginary part, and results in a balanced loss/gain metamaterial slab. A CSP produces a Gaussian beam and, consequently, a point source placed at the center of such a metamaterial slab produces a Gaussian beam propagating away from the slab. Here, we extend the CTO analysis to nonsymmetric complex coordinate transformations as put forth in [S. Savoia, G. Castaldi, and V. Galdi, J. Opt. 18, 044027 (2016), 10.1088/2040-8978/18/4/044027] and verify that, by using simply a (homogeneous) doubly anisotropic gain-media metamaterial slab, one can still mimic a CSP and produce Gaussian beam. In addition, we show that a Gaussian-like beams can be produced by point sources placed outside the slab as well. By making use of the extra degrees of freedom (the real and imaginary parts of the coordinate transformation) provided by CTO, the near-zero requirement on the real part of the resulting constitutive parameters can be relaxed to facilitate potential realization of Gaussian-like beams. We illustrate how beam properties such as peak amplitude and waist location can be controlled by a proper choice of (complex-valued) CTO Jacobian elements. In particular, the beam waist

Development of improved connection details for adjacent prestressed member bridges.

DOT National Transportation Integrated Search

2017-06-01

Adjacent prestressed member girder bridges are economical systems for short spans and generally come in two types: adjacent box beam bridges and adjacent voided slab bridges. Each type provides the advantages of having low clearances because of their...

Improved connection details for adjacent prestressed bridge beams.

DOT National Transportation Integrated Search

2015-03-01

Bridges with adjacent box beams and voided slabs are simply and rapidly constructed, and are well suited to : short to medium spans. The traditional connection between the adjacent members is a shear key lled with a : conventional non-shrink grout...

Adjacency Matrix-Based Transmit Power Allocation Strategies in Wireless Sensor Networks

PubMed Central

Consolini, Luca; Medagliani, Paolo; Ferrari, Gianluigi

2009-01-01

In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes where several remote nodes send data directly to a common access point (AP). Under the assumption of finite overall network transmit power and low traffic load, we derive the optimal transmit power allocation strategy that minimizes the packet error rate (PER) at the AP. This approach is based on modeling the CSMA/CA MAC protocol through a finite state machine and takes into account the network adjacency matrix, depending on the transmit power distribution and determining the network connectivity. It will be then shown that the transmit power allocation problem reduces to a convex constrained minimization problem. Our results show that, under the assumption of low traffic load, the power allocation strategy, which guarantees minimal delay, requires the maximization of network connectivity, which can be equivalently interpreted as the maximization of the number of non-zero entries of the adjacency matrix. The obtained theoretical results are confirmed by simulations for unslotted Zigbee WSNs. PMID:22346705

HIGH VOLTAGE ION SOURCE

DOEpatents

Luce, J.S.

1960-04-19

A device is described for providing a source of molecular ions having a large output current and with an accelerated energy of the order of 600 kv. Ions are produced in an ion source which is provided with a water-cooled source grid of metal to effect maximum recombination of atomic ions to molecular ions. A very high accelerating voltage is applied to withdraw and accelerate the molecular ions from the source, and means are provided for dumping the excess electrons at the lowest possible potentials. An accelerating grid is placed adjacent to the source grid and a slotted, grounded accelerating electrode is placed adjacent to the accelerating grid. A potential of about 35 kv is maintained between the source grid and accelerating grid, and a potential of about 600 kv is maintained between the accelerating grid and accelerating electrode. In order to keep at a minimum the large number of oscillating electrons which are created when such high voltages are employed in the vicinity of a strong magnetic field, a plurality of high voltage cascaded shields are employed with a conventional electron dumping system being employed between each shield so as to dump the electrons at the lowest possible potential rather than at 600 kv.

75 FR 68305 - Proposed Rule Staying Numeric Limitation for the Construction and Development Point Source Category

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-05

... coverage and performing the following activities: Construction of buildings, including building, developing... Staying Numeric Limitation for the Construction and Development Point Source Category AGENCY... effluent limitation of 280 NTU and associated monitoring requirements for the Construction and Development...

VizieR Online Data Catalog: XMM-Newton point-source catalogue of the SMC (Sturm+, 2013)

NASA Astrophysics Data System (ADS)

Sturm, R.; Haberl, F.; Pietsch, W.; Ballet, J.; Hatzidimitriou, D.; Buckley, D. A. H.; Coe, M.; Ehle, M.; Filipovic, M. D.; La Palombara, N.; Tiengo, A.

2013-07-01

The XMM-Newton survey of the Small Magellanic Cloud (SMC) yields a complete coverage of the bar and eastern wing in the 0.2-12.0keV band. This catalogue comprises 3053 unique X-ray point sources and sources with moderate extent that have been reduced from 5236 individual detections found in observations between April 2000 and April 2010. Sources have a median position uncertainty of 1.3" (1σ) and limiting fluxes down to ~1*10-14erg/s/cm2 in the 0.2-4.5keV band, corresponding to 5*1033erg/s for sources in the SMC. Sources have been classified using hardness ratios, X-ray variability, and their multi-wavelength properties. In addition to the main-field (5.58deg2) available outer fields have been included in the catalogue, yielding a total field area of 6.32deg2. X-ray sources with high extent (>40", e.g. supernova remnants and galaxy cluster) have been presented by Haberl et al. (2012, Cat. J/A+A/545/A128) (2 data files).

75 FR 68215 - Direct Final Rule Staying Numeric Limitation for the Construction and Development Point Source...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-05

... required to obtain NPDES permit coverage and performing the following activities: Construction of buildings, including building, developing and general contracting. Heavy and civil 237 engineering construction... Rule Staying Numeric Limitation for the Construction and Development Point Source Category AGENCY...

Vector image method for the derivation of elastostatic solutions for point sources in a plane layered medium. Part 1: Derivation and simple examples

NASA Technical Reports Server (NTRS)

Fares, Nabil; Li, Victor C.

1986-01-01

An image method algorithm is presented for the derivation of elastostatic solutions for point sources in bonded halfspaces assuming the infinite space point source is known. Specific cases were worked out and shown to coincide with well known solutions in the literature.

Major and Trace Element Fluxes to the Ganges River: Significance of Small Flood Plain Tributary as Non-Point Pollution Source

NASA Astrophysics Data System (ADS)

Lakshmi, V.; Sen, I. S.; Mishra, G.

2017-12-01

There has been much discussion amongst biologists, ecologists, chemists, geologists, environmental firms, and science policy makers about the impact of human activities on river health. As a result, multiple river restoration projects are on going on many large river basins around the world. In the Indian subcontinent, the Ganges River is the focal point of all restoration actions as it provides food and water security to half a billion people. Serious concerns have been raised about the quality of Ganga water as toxic chemicals and many more enters the river system through point-sources such as direct wastewater discharge to rivers, or non-point-sources. Point source pollution can be easily identified and remedial actions can be taken; however, non-point pollution sources are harder to quantify and mitigate. A large non-point pollution source in the Indo-Gangetic floodplain is the network of small floodplain rivers. However, these rivers are rarely studied since they are small in catchment area ( 1000-10,000 km2) and discharge (<100 m3/s). As a result, the impact of these small floodplain rivers on the dissolved chemical load of large river systems is not constrained. To fill this knowledge gap we have monitored the Pandu River for one year between February 2015 and April 2016. Pandu river is 242 km long and is a right bank tributary of Ganges with a total catchment area of 1495 km2. Water samples were collected every month for dissolved major and trace elements. Here we show that the concentration of heavy metals in river Pandu is in higher range as compared to the world river average, and all the dissolved elements shows a large spatial-temporal variation. We show that the Pandu river exports 192170, 168517, 57802, 32769, 29663, 1043, 279, 241, 225, 162, 97, 28, 25, 22, 20, 8, 4 Kg/yr of Ca, Na, Mg, K, Si, Sr, Zn, B, Ba, Mn, Al, Li, Rb, Mo, U, Cu, and Sb, respectively, to the Ganga river, and the exported chemical flux effects the water chemistry of the Ganga

3-D localization of virtual sound sources: effects of visual environment, pointing method, and training.

PubMed

Majdak, Piotr; Goupell, Matthew J; Laback, Bernhard

2010-02-01

The ability to localize sound sources in three-dimensional space was tested in humans. In Experiment 1, naive subjects listened to noises filtered with subject-specific head-related transfer functions. The tested conditions included the pointing method (head or manual pointing) and the visual environment (VE; darkness or virtual VE). The localization performance was not significantly different between the pointing methods. The virtual VE significantly improved the horizontal precision and reduced the number of front-back confusions. These results show the benefit of using a virtual VE in sound localization tasks. In Experiment 2, subjects were provided with sound localization training. Over the course of training, the performance improved for all subjects, with the largest improvements occurring during the first 400 trials. The improvements beyond the first 400 trials were smaller. After the training, there was still no significant effect of pointing method, showing that the choice of either head- or manual-pointing method plays a minor role in sound localization performance. The results of Experiment 2 reinforce the importance of perceptual training for at least 400 trials in sound localization studies.

Study on the quantitative relationship between Agricultural water and fertilization process and non-point source pollution based on field experiments

NASA Astrophysics Data System (ADS)

Wang, H.; Chen, K.; Wu, Z.; Guan, X.

2017-12-01

In recent years, with the prominent of water environment problem and the relative increase of point source pollution governance, especially the agricultural non-point source pollution problem caused by the extensive use of fertilizers and pesticides has become increasingly aroused people's concern and attention. In order to reveal the quantitative relationship between agriculture water and fertilizer and non-point source pollution, on the basis of elm field experiment and combined with agricultural drainage irrigation model, the agricultural irrigation water and the relationship between fertilizer and fertilization scheme and non-point source pollution were analyzed and calculated by field emission intensity index. The results show that the variation of displacement varies greatly under different irrigation conditions. When the irrigation water increased from 22cm to 42cm, the irrigation water increased by 20 cm while the field displacement increased by 11.92 cm, about 66.22% of the added value of irrigation water. Then the irrigation water increased from 42 to 68, irrigation water increased 26 cm, and the field displacement increased by 22.48 cm, accounting for 86.46% of irrigation water. So there is an "inflection point" between the irrigation water amount and field displacement amount. The load intensity increases with the increase of irrigation water and shows a significant power correlation. Under the different irrigation condition, the increase amplitude of load intensity with the increase of irrigation water is different. When the irrigation water is smaller, the load intensity increase relatively less, and when the irrigation water increased to about 42 cm, the load intensity will increase considerably. In addition, there was a positive correlation between the fertilization and load intensity. The load intensity had obvious difference in different fertilization modes even with same fertilization level, in which the fertilizer field unit load intensity

THE FIRST COMBINED SEARCH FOR NEUTRINO POINT-SOURCES IN THE SOUTHERN HEMISPHERE WITH THE ANTARES AND ICECUBE NEUTRINO TELESCOPES

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

Adrián-Martínez, S.; Ardid, M.; Albert, A.

2016-05-20

We present the results of searches for point-like sources of neutrinos based on the first combined analysis of data from both the ANTARES and IceCube neutrino telescopes. The combination of both detectors, which differ in size and location, forms a window in the southern sky where the sensitivity to point sources improves by up to a factor of 2 compared with individual analyses. Using data recorded by ANTARES from 2007 to 2012, and by IceCube from 2008 to 2011, we search for sources of neutrino emission both across the southern sky and from a preselected list of candidate objects. Nomore » significant excess over background has been found in these searches, and flux upper limits for the candidate sources are presented for E {sup −2.5} and E {sup −2} power-law spectra with different energy cut-offs.« less

The XXL Survey. VI. The 1000 brightest X-ray point sources

NASA Astrophysics Data System (ADS)

Fotopoulou, S.; Pacaud, F.; Paltani, S.; Ranalli, P.; Ramos-Ceja, M. E.; Faccioli, L.; Plionis, M.; Adami, C.; Bongiorno, A.; Brusa, M.; Chiappetti, L.; Desai, S.; Elyiv, A.; Lidman, C.; Melnyk, O.; Pierre, M.; Piconcelli, E.; Vignali, C.; Alis, S.; Ardila, F.; Arnouts, S.; Baldry, I.; Bremer, M.; Eckert, D.; Guennou, L.; Horellou, C.; Iovino, A.; Koulouridis, E.; Liske, J.; Maurogordato, S.; Menanteau, F.; Mohr, J. J.; Owers, M.; Poggianti, B.; Pompei, E.; Sadibekova, T.; Stanford, A.; Tuffs, R.; Willis, J.

2016-06-01

Context. X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). Usually, a combination of deep and wide surveys is necessary to create a complete picture of the population. Deep X-ray surveys provide the faint population at high redshift, while wide surveys provide the rare bright sources. Nevertheless, very wide area surveys often lack the ancillary information available for modern deep surveys. The XXL survey spans two fields of a combined 50 deg2 observed for more than 6Ms with XMM-Newton, occupying the parameter space that lies between deep surveys and very wide area surveys; at the same time it benefits from a wealth of ancillary data. Aims: This paper marks the first release of the XXL point source catalogue including four optical photometry bands and redshift estimates. Our sample is selected in the 2 - 10 keV energy band with the goal of providing a sizable sample useful for AGN studies. The limiting flux is F2 - 10 keV = 4.8 × 10-14 erg s-1 cm-2. Methods: We use both public and proprietary data sets to identify the counterparts of the X-ray point-like sources by means of a likelihood ratio test. We improve upon the photometric redshift determination for AGN by applying a Random Forest classification trained to identify for each object the optimal photometric redshift category (passive, star forming, starburst, AGN, quasi-stellar objects (QSO)). Additionally, we assign a probability to each source that indicates whether it might be a star or an outlier. We apply Bayesian analysis to model the X-ray spectra assuming a power-law model with the presence of an absorbing medium. Results: We find that the average unabsorbed photon index is ⟨Γ⟩ = 1.85 ± 0.40 while the average hydrogen column density is log ⟨NH⟩ = 21.07 ± 1.2 cm-2. We find no trend of Γ or NH with redshift and a fraction of 26% absorbed sources (log NH> 22) consistent with the literature on bright sources (log

VizieR Online Data Catalog: ChaMP X-ray point source catalog (Kim+, 2007)

NASA Astrophysics Data System (ADS)

Kim, M.; Kim, D.-W.; Wilkes, B. J.; Green, P. J.; Kim, E.; Anderson, C. S.; Barkhouse, W. A.; Evans, N. R.; Ivezic, Z.; Karovska, M.; Kashyap, V. L.; Lee, M. G.; Maksym, P.; Mossman, A. E.; Silverman, J. D.; Tananbaum, H. D.

2009-01-01

We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6800 X-ray sources detected in 149 Chandra observations covering ~10deg2. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124ks, corresponding to a deepest X-ray flux limit of f0.5-8.0=9x10-16ergs/cm2/s. The ChaMP X-ray data have been uniformly reduced and analyzed with ChaMP-specific pipelines and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in eight different energy bands as well as X-ray spectral hardness ratios and colors. To best utilize the ChaMP catalog, we also present the source reliability, detection probability, and positional uncertainty. (10 data files).

Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

NASA Astrophysics Data System (ADS)

Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

2013-04-01

This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

Point Source All Sky

NASA Image and Video Library

2003-03-27

This panoramic view encompasses the entire sky as seen by Two Micron All-Sky Survey. The measured brightnesses of half a billion stars (points) have been combined into colors representing three distinct wavelengths of infrared light: blue at 1.2 microns, green at 1.6 microns, and red at 2.2 microns. This image is centered on the core of our own Milky Way galaxy, toward the constellation of Sagittarius. The reddish stars seemingly hovering in the middle of the Milky Way's disc -- many of them never observed before -- trace the densest dust clouds in our galaxy. The two faint smudges seen in the lower right quadrant are our neighboring galaxies, the Small and Large Magellanic Clouds. http://photojournal.jpl.nasa.gov/catalog/PIA04250

Learning Non-Adjacent Regularities at Age 0 ; 7

ERIC Educational Resources Information Center

Gervain, Judit; Werker, Janet F.

2013-01-01

One important mechanism suggested to underlie the acquisition of grammar is rule learning. Indeed, infants aged 0 ; 7 are able to learn rules based on simple identity relations (adjacent repetitions, ABB: "wo fe fe" and non-adjacent repetitions, ABA: "wo fe wo", respectively; Marcus et al., 1999). One unexplored issue is…

Numerical modeling of a point-source image under relative motion of radiation receiver and atmosphere

NASA Astrophysics Data System (ADS)

Kucherov, A. N.; Makashev, N. K.; Ustinov, E. V.

1994-02-01

A procedure is proposed for numerical modeling of instantaneous and averaged (over various time intervals) distant-point-source images perturbed by a turbulent atmosphere that moves relative to the radiation receiver. Examples of image calculations under conditions of the significant effect of atmospheric turbulence in an approximation of geometrical optics are presented and analyzed.

Emissions of perfluorinated alkylated substances (PFAS) from point sources--identification of relevant branches.

PubMed

Clara, M; Scheffknecht, C; Scharf, S; Weiss, S; Gans, O

2008-01-01

Effluents of wastewater treatment plants are relevant point sources for the emission of hazardous xenobiotic substances to the aquatic environment. One group of substances, which recently entered scientific and political discussions, is the group of the perfluorinated alkylated substances (PFAS). The most studied compounds from this group are perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), which are the most important degradation products of PFAS. These two substances are known to be persistent, bioaccumulative and toxic (PBT). In the present study, eleven PFAS were investigated in effluents of municipal wastewater treatment plants (WWTP) and in industrial wastewaters. PFOS and PFOA proved to be the dominant compounds in all sampled wastewaters. Concentrations of up to 340 ng/L of PFOS and up to 220 ng/L of PFOA were observed. Besides these two compounds, perfluorohexanoic acid (PFHxA) was also present in nearly all effluents and maximum concentrations of up to 280 ng/L were measured. Only N-ethylperfluorooctane sulphonamide (N-EtPFOSA) and its degradation/metabolisation product perfluorooctane sulphonamide (PFOSA) were either detected below the limit of quantification or were not even detected at all. Beside the effluents of the municipal WWTPs, nine industrial wastewaters from six different industrial branches were also investigated. Significantly, the highest emissions or PFOS were observed from metal industry whereas paper industry showed the highest PFOA emission. Several PFAS, especially perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and PFOS are predominantly emitted from industrial sources, with concentrations being a factor of 10 higher than those observed in the municipal WWTP effluents. Perfluorodecane sulphonate (PFDS), N-Et-PFOSA and PFOSA were not detected in any of the sampled industrial point sources. (c) IWA Publishing 2008.

Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

NASA Technical Reports Server (NTRS)

Woronowicz, Michael S.

2016-01-01

Analytical expressions for column number density (CND) are developed for optical line of sight paths through a variety of steady free molecule point source models including directionally-constrained effusion (Mach number M = 0) and flow from a sonic orifice (M 1). Sonic orifice solutions are approximate, developed using a fair simulacrum fitted to the free molecule solution. Expressions are also developed for a spherically-symmetric thermal expansion (M = 0). CND solutions are found for the most general paths relative to these sources and briefly explored. It is determined that the maximum CND from a distant location through directed effusion and sonic orifice cases occurs along the path parallel to the source plane that intersects the plume axis. For the effusive case this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plumes axis. For sonic plumes this ratio is reduced to about 43. For high Mach number cases the maximum CND will be found along the axial centerline path.

Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2016-01-01

Analytical expressions for column number density (CND) are developed for optical line of sight paths through a variety of steady free molecule point source models including directionally-constrained effusion (Mach number M = 0) and flow from a sonic orifice (M = 1). Sonic orifice solutions are approximate, developed using a fair simulacrum fitted to the free molecule solution. Expressions are also developed for a spherically-symmetric thermal expansion (M = 0). CND solutions are found for the most general paths relative to these sources and briefly explored. It is determined that the maximum CND from a distant location through directed effusion and sonic orifice cases occurs along the path parallel to the source plane that intersects the plume axis. For the effusive case this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plume's axis. For sonic plumes this ratio is reduced to about 4/3. For high Mach number cases the maximum CND will be found along the axial centerline path. Keywords: column number density, plume flows, outgassing, free molecule flow.

Scalar Dispersion from Point Sources in a Realistic Urban Environment

NASA Astrophysics Data System (ADS)

Salesky, S.; Giometto, M. G.; Christen, A.; Parlange, M. B.

2016-12-01

Accurate modeling of scalar dispersion within and above urban canopies is critical to properly predict air quality and dispersion (e.g. accidental contaminant release) in urban environments. We perform large eddy simulations (LES) of scalar dispersion from point sources in a typical North American neighborhood using topography and foliage density derived from airborne LIDAR scans with 1 m resolution in Vancouver, BC, Canada. The added drag force due to trees is parameterized in the LES as a function of the leaf area density (LAD) profile. Conversely, drag from buildings is accounted for using a direct forcing approach immersed-boundary method. The scalar advection-diffusion equation is discretized in a finite-volume framework, and accurate mass conservation is enforced through a recently developed Cartesian cut cell method. Simulations are performed with trees for different values of LAD, representative of summer and winter conditions, as well as a case without trees. The effects of varying mean wind direction (derived from observed wind climatologies) on dispersion patterns are also considered. Scalar release locations in the LES are informed by spatially distributed measurements of carbon dioxide concentration; CO2 is used as a tracer for fossil fuel emissions, since source strengths are well-known and the contribution from biological processes in this setting is small (<10%). The effects of leaf area density, source height, and wind direction on scalar statistics including the growth of the mean concentration plume and the fraction that escapes the urban canopy layer will be considered. In a companion study, the presence of trees was found to strongly modify sweep and ejection patterns for the momentum flux; here we consider the related issue of how vegetation influences coherent structures responsible for scalar transport.

Comparison of vertical hydraulic conductivity in a streambed-point bar system of a gaining stream

NASA Astrophysics Data System (ADS)

Dong, Weihong; Chen, Xunhong; Wang, Zhaowei; Ou, Gengxin; Liu, Can

2012-07-01

SummaryVertical hydraulic conductivities (Kv) of both streambed and point bars can influence water and solute exchange between streams and surrounding groundwater systems. The sediments in point bars are relatively young compared to the older sediments in the adjacent aquifers but slightly older compared to submerged streambeds. Thus, the permeability in point bar sediments can be different not only from regional aquifer but also from modern streambed. However, there is a lack of detailed studies that document spatial variability of vertical hydraulic conductivity in point bars of meandering streams. In this study, the authors proposed an in situ permeameter test method to measure vertical hydraulic conductivity of the two point bars in Clear Creek, Nebraska, USA. We compared the Kv values in streambed and adjacent point bars through 45 test locations in the two point bars and 51 test locations in the streambed. The Kv values in the point bars were lower than those in the streambed. Kruskal-Wallis test confirmed that the Kv values from the point bars and from the channel came from two statistically different populations. Within a point bar, the Kv values were higher along the point bar edges than those from inner point bars. Grain size analysis indicated that slightly more silt and clay particles existed in sediments from inner point bars, compared to that from streambed and from locations near the point bar edges. While point bars are the deposits of the adjacent channel, the comparison of two groups of Kv values suggests that post-depositional processes had an effect on the evolution of Kv from channel to point bars in fluvial deposits. We believed that the transport of fine particles and the gas ebullition in this gaining stream had significant effects on the distribution of Kv values in a streambed-point bar system. With the ageing of deposition in a floodplain, the permeability of point bar sediments can likely decrease due to reduced effects of the upward

Normalized Point Source Sensitivity for Off-Axis Optical Performance Evaluation of the Thirty Meter Telescope

NASA Technical Reports Server (NTRS)

Seo, Byoung-Joon; Nissly, Carl; Troy, Mitchell; Angeli, George

2010-01-01

The Normalized Point Source Sensitivity (PSSN) has previously been defined and analyzed as an On-Axis seeing-limited telescope performance metric. In this paper, we expand the scope of the PSSN definition to include Off-Axis field of view (FoV) points and apply this generalized metric for performance evaluation of the Thirty Meter Telescope (TMT). We first propose various possible choices for the PSSN definition and select one as our baseline. We show that our baseline metric has useful properties including the multiplicative feature even when considering Off-Axis FoV points, which has proven to be useful for optimizing the telescope error budget. Various TMT optical errors are considered for the performance evaluation including segment alignment and phasing, segment surface figures, temperature, and gravity, whose On-Axis PSSN values have previously been published by our group.

[Regulation framework of watershed landscape pattern for non-point source pollution control based on 'source-sink' theory: A case study in the watershed of Maluan Bay, Xiamen City, China].

PubMed

Huang, Ning; Wang, Hong Ying; Lin, Tao; Liu, Qi Ming; Huang, Yun Feng; Li, Jian Xiong

2016-10-01

Watershed landscape pattern regulation and optimization based on 'source-sink' theory for non-point source pollution control is a cost-effective measure and still in the exploratory stage. Taking whole watershed as the research object, on the basis of landscape ecology, related theories and existing research results, a regulation framework of watershed landscape pattern for non-point source pollution control was developed at two levels based on 'source-sink' theory in this study: 1) at watershed level: reasonable basic combination and spatial pattern of 'source-sink' landscape was analyzed, and then holistic regulation and optimization method of landscape pattern was constructed; 2) at landscape patch level: key 'source' landscape was taken as the focus of regulation and optimization. Firstly, four identification criteria of key 'source' landscape including landscape pollutant loading per unit area, landscape slope, long and narrow transfer 'source' landscape, pollutant loading per unit length of 'source' landscape along the riverbank were developed. Secondly, nine types of regulation and optimization methods for different key 'source' landscape in rural and urban areas were established, according to three regulation and optimization rules including 'sink' landscape inlay, banding 'sink' landscape supplement, pollutants capacity of original 'sink' landscape enhancement. Finally, the regulation framework was applied for the watershed of Maluan Bay in Xiamen City. Holistic regulation and optimization mode of watershed landscape pattern of Maluan Bay and key 'source' landscape regulation and optimization measures for the three zones were made, based on GIS technology, remote sensing images and DEM model.

Calculations of the electrostatic potential adjacent to model phospholipid bilayers.

PubMed

Peitzsch, R M; Eisenberg, M; Sharp, K A; McLaughlin, S

1995-03-01

We used the nonlinear Poisson-Boltzmann equation to calculate electrostatic potentials in the aqueous phase adjacent to model phospholipid bilayers containing mixtures of zwitterionic lipids (phosphatidylcholine) and acidic lipids (phosphatidylserine or phosphatidylglycerol). The aqueous phase (relative permittivity, epsilon r = 80) contains 0.1 M monovalent salt. When the bilayers contain < 11% acidic lipid, the -25 mV equipotential surfaces are discrete domes centered over the negatively charged lipids and are approximately twice the value calculated using Debye-Hückel theory. When the bilayers contain > 25% acidic lipid, the -25 mV equipotential profiles are essentially flat and agree well with the values calculated using Gouy-Chapman theory. When the bilayers contain 100% acidic lipid, all of the equipotential surfaces are flat and agree with Gouy-Chapman predictions (including the -100 mV surface, which is located only 1 A from the outermost atoms). Even our model bilayers are not simple systems: the charge on each lipid is distributed over several atoms, these partial charges are non-coplanar, there is a 2 A ion-exclusion region (epsilon r = 80) adjacent to the polar headgroups, and the molecular surface is rough. We investigated the effect of these four factors using smooth (or bumpy) epsilon r = 2 slabs with embedded point charges: these factors had only minor effects on the potential in the aqueous phase.

Distinguishing the Effects of Local Point Sources from Those Caused by Upstream Nonpoint Source (NPS) Inputs: Refinement of a Watershed Development Index for New England

EPA Science Inventory

Using EMAP data from the NE Wadeable Stream Survey and state datasets (CT, ME), assessment tools were developed to predict diffuse NPS effects from watershed development and distinguish these from local impacts (point sources, contaminated sediments). Classification schemes were...

A systematic review of definitions and classification systems of adjacent segment pathology.

PubMed

Kraemer, Paul; Fehlings, Michael G; Hashimoto, Robin; Lee, Michael J; Anderson, Paul A; Chapman, Jens R; Raich, Annie; Norvell, Daniel C

2012-10-15

Systematic review. To undertake a systematic review to determine how "adjacent segment degeneration," "adjacent segment disease," or clinical pathological processes that serve as surrogates for adjacent segment pathology are classified and defined in the peer-reviewed literature. Adjacent segment degeneration and adjacent segment disease are terms referring to degenerative changes known to occur after reconstructive spine surgery, most commonly at an immediately adjacent functional spinal unit. These can include disc degeneration, instability, spinal stenosis, facet degeneration, and deformity. The true incidence and clinical impact of degenerative changes at the adjacent segment is unclear because there is lack of a universally accepted classification system that rigorously addresses clinical and radiological issues. A systematic review of the English language literature was undertaken and articles were classified using the Grades of Recommendation Assessment, Development, and Evaluation criteria. RESULTS.: Seven classification systems of spinal degeneration, including degeneration at the adjacent segment, were identified. None have been evaluated for reliability or validity specific to patients with degeneration at the adjacent segment. The ways in which terms related to adjacent segment "degeneration" or "disease" are defined in the peer-reviewed literature are highly variable. On the basis of the systematic review presented in this article, no formal classification system for either cervical or thoracolumbar adjacent segment disorders currently exists. No recommendations regarding the use of current classification of degeneration at any segments can be made based on the available literature. A new comprehensive definition for adjacent segment pathology (ASP, the now preferred terminology) has been proposed in this Focus Issue, which reflects the diverse pathology observed at functional spinal units adjacent to previous spinal reconstruction and balances

Delayed Acquisition of Non-Adjacent Vocalic Distributional Regularities

ERIC Educational Resources Information Center

Gonzalez-Gomez, Nayeli; Nazzi, Thierry

2016-01-01

The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two…

The 1.4-2.7 micron spectrum of the point source at the galactic center

NASA Technical Reports Server (NTRS)

Treffers, R. R.; Fink, U.; Larson, H. P.; Gautier, T. N., III

1976-01-01

The spectrum of the 2-micron point source at the galactic center is presented over the range from 1.4 to 2.7 microns. The two-level-transition CO band heads are seen near 2.3 microns, confirming that the radiation from this source is due to a cool supergiant star. The heliocentric radial velocity is found to be - 173 (+ or -90) km/s and is consistent with the star being in orbit about a dense galactic nucleus. No evidence is found for Brackett-gamma emission, and no interstellar absorption features are seen. Upper limits for the column densities of interstellar H2, CH4, CO, and NH3 are derived.

Nutrient Losses from Non-Point Sources or from Unidentified Point Sources? Application Examples of the Smartphone Based Nitrate App.

NASA Astrophysics Data System (ADS)

Rozemeijer, J.; Ekkelenkamp, R.; van der Zaan, B.

2017-12-01

In 2016 Deltares launched the free to use Nitrate App which accurately reads and interprets nitrate test strips. The app directly displays the measured concentration and gives the option to share the result. Shared results are visualised in map functionality within the app and online. Since its introduction we've been seeing an increasing number of nitrate app applications. In this presentation we show some unanticipated types of application. The Nitrate App was originally intended to enable farmers to measure nitrate concentrations on their own farms. This may encourage farmers to talk to specialists about the right nutrient best management practices (BMP's) for their farm. Several groups of farmers have recently started to apply the Nitrate App and to discuss their results with each other and with the authorities. Nitrate concentration routings in catchments have proven to be another useful application. Within a day a person can generate a catchment scale nitrate concentration map identifying nitrate loss hotspots. In several routings in agricultural catchments clear point sources were found, for example at small scale manure processing plants. These routings proved that the Nitrate App can help water managers to target conservation practices more accurately to areas with the highest nitrate concentrations and loads. Other current applications are the screening of domestic water wells in California, the collection of extra measurements (also pH and NH4) in the National Monitoring Network for the Evaluation of the Manure Policy in the Netherlands, and several educational initiatives in cooperation with schools and universities.

Presence of Pathogens and Indicator Microbes at a Non-Point Source Subtropical Recreational Marine Beach ▿ †

PubMed Central

Abdelzaher, Amir M.; Wright, Mary E.; Ortega, Cristina; Solo-Gabriele, Helena M.; Miller, Gary; Elmir, Samir; Newman, Xihui; Shih, Peter; Bonilla, J. Alfredo; Bonilla, Tonya D.; Palmer, Carol J.; Scott, Troy; Lukasik, Jerzy; Harwood, Valerie J.; McQuaig, Shannon; Sinigalliano, Chris; Gidley, Maribeth; Plano, Lisa R. W.; Zhu, Xiaofang; Wang, John D.; Fleming, Lora E.

2010-01-01

Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted

Point X-ray sources in the SNR G 315.4-2.30 (MSH 14-63, RCW 86)

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.; Vikhlinin, A. A.

2003-04-01

We report the results of a search for a point X-ray source (stellar remnant) in the southwest protrusion of the supernova remnant G 315.4-2.30 (MSH 14-63, RCW 86) using the archival data of the Chandra X-ray Observatory. The search was motivated by a hypothesis that G 315.4-2.30 is the result of an off-centered cavity supernova explosion of a moving massive star, which ended its evolution just near the edge of the main-sequence wind-driven bubble. This hypothesis implies that the southwest protrusion in G 315.4-2.30 is the remainder of a pre-existing bow shock-like structure created by the interaction of the supernova progenitor's wind with the interstellar medium and that the actual location of the supernova blast center is near the center of this hemispherical structure. We have discovered two point X-ray sources in the ``proper" place. One of the sources has an optical counterpart with the photographic magnitude 13.38+/-0.40, while the spectrum of the source can be fitted with an optically thin plasma model. We interpret this source as a foreground active star of late spectral type. The second source has no optical counterpart to a limiting magnitude ~ 21. The spectrum of this source can be fitted almost equally well with several simple models (power law: photon index =1.87; two-temperature blackbody: kT1 =0.11 keV, R1 =2.34 km and kT2 =0.71 keV, R2 =0.06 km; blackbody plus power law: kT =0.07 keV, photon index =2.3). We interpret this source as a candidate stellar remnant (neutron star), while the photon index and non-thermal luminosity of the source (almost the same as those of the Vela pulsar and the recently discovered pulsar PSR J 0205+6449 in the supernova remnant 3C 58) suggest that it can be a young ``ordinary" pulsar.

Distinguishing Betwen Effects of Local Inputs (Contaminated Sediments, Point Sources) and Upstream Diffuse Nonpoint Source Input: Refinement of a Watershed Development Index for New England

EPA Science Inventory

Assessment tools are being developed to predict diffuse NPS effects from watershed development and distinguish these from local impacts (point sources, contaminated sediments). Using EMAP data from the New England Wadeable Stream Survey and two state datasets (CT, ME), we are de...

CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES IN NEARBY GALAXIES. II. X-RAY LUMINOSITY FUNCTIONS AND ULTRALUMINOUS X-RAY SOURCES

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

Wang, Song; Qiu, Yanli; Liu, Jifeng

Based on the recently completed Chandra /ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm withmore » good statistics that the XLF slope flattens from lenticular ( α ∼ 1.50 ± 0.07) to elliptical (∼1.21 ± 0.02), to spirals (∼0.80 ± 0.02), to peculiars (∼0.55 ± 0.30), and to irregulars (∼0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D {sub 25} and 2 D {sub 25}, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5 σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 10{sup 40} erg s{sup −1}, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M {sub ⊙} black holes with super-Eddington radiation and intermediate mass black holes.« less

Minimization of model representativity errors in identification of point source emission from atmospheric concentration measurements

NASA Astrophysics Data System (ADS)

Sharan, Maithili; Singh, Amit Kumar; Singh, Sarvesh Kumar

2017-11-01

Estimation of an unknown atmospheric release from a finite set of concentration measurements is considered an ill-posed inverse problem. Besides ill-posedness, the estimation process is influenced by the instrumental errors in the measured concentrations and model representativity errors. The study highlights the effect of minimizing model representativity errors on the source estimation. This is described in an adjoint modelling framework and followed in three steps. First, an estimation of point source parameters (location and intensity) is carried out using an inversion technique. Second, a linear regression relationship is established between the measured concentrations and corresponding predicted using the retrieved source parameters. Third, this relationship is utilized to modify the adjoint functions. Further, source estimation is carried out using these modified adjoint functions to analyse the effect of such modifications. The process is tested for two well known inversion techniques, called renormalization and least-square. The proposed methodology and inversion techniques are evaluated for a real scenario by using concentrations measurements from the Idaho diffusion experiment in low wind stable conditions. With both the inversion techniques, a significant improvement is observed in the retrieval of source estimation after minimizing the representativity errors.

Geologic map of the Lazy Y Point Quadrangle, Moffat County Colorado

USGS Publications Warehouse

Van Loenen, R. E.; Selner, G.I.; Bryant, W.A.

1999-01-01

The Lazy Y Point quadrangle is in northwestern Colorado a few miles north of Rangely. The prominent structural feature of the Lazy Y Point quadrangle is the Skull Creek monocline. Pennsylvanian rocks are exposed along the axis of the monocline while hogbacks along its southern flank expose rocks that are from Permian to Upper Cretaceous in age. The Wolf Creek monocline and the Wolf Creek thrust fault, which dissects the monocline, are salient structural features in the northern part of the quadrangle. Little or no mineral potential exists within the quadrangle. A geologic map of the Skull Creek quadrangle, which is adjacent to the Lazy Y Point quadrangle on the east, is also available (Geologic Investigations Series I-2647). This companian map shows similar geologic features, including the eastern half of the Skull Creek monocline. The geology of this quadrangle was mapped because of its proximity to Dinosaur National Monument. It is adjacent to quadrangles previously mapped to display the geology of this very scenic and popular National Monument. The Lazy Y Point quadrangle includes parts of the Willow and Skull Creek Wilderness Study Areas, which were assessed for their mineral resource potential.

Induction heating pure vapor source of high temperature melting point materials on electron cyclotron resonance ion sourcea)

NASA Astrophysics Data System (ADS)

Kutsumi, Osamu; Kato, Yushi; Matsui, Yuuki; Kitagawa, Atsushi; Muramatsu, Masayuki; Uchida, Takashi; Yoshida, Yoshikazu; Sato, Fuminobu; Iida, Toshiyuki

2010-02-01

Multicharged ions that are needed are produced from solid pure material with high melting point in an electron cyclotron resonance ion source. We develop an evaporator by using induction heating (IH) with multilayer induction coil, which is made from bare molybdenum or tungsten wire without water cooling and surrounding the pure vaporized material. We optimize the shapes of induction coil and vaporized materials and operation of rf power supply. We conduct experiment to investigate the reproducibility and stability in the operation and heating efficiency. IH evaporator produces pure material vapor because materials directly heated by eddy currents have no contact with insulated materials, which are usually impurity gas sources. The power and the frequency of the induction currents range from 100to900W and from 48to23kHz, respectively. The working pressure is about 10-4-10-3Pa. We measure the temperature of the vaporized materials with different shapes, and compare them with the result of modeling. We estimate the efficiency of the IH vapor source. We are aiming at the evaporator's higher melting point material than that of iron.

Objectifying the adjacent and opposite angles: a cultural historical analysis

NASA Astrophysics Data System (ADS)

Daher, Wajeeh; Musallam, Nadera

2018-02-01

The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles' concepts. We videoed the learning of a group of three high-achieving students who used technology, specifically GeoGebra, to explore geometric relations related to the adjacent and opposite angles' concepts. To analyze students' objectification of these concepts, we used the categories of objectification of knowledge (attention and awareness) and the categories of generalization (factual, contextual and symbolic), developed by Radford. The research results indicate that teacher's and students' verbal and visual signs, together with the software dynamic tools, mediated the students' objectification of the adjacent and opposite angles' concepts. Specifically, eye and gestures perceiving were part of the semiosis cycles in which the participating students were engaged and which related to the mathematical signs that signified the adjacent and the opposite angles. Moreover, the teacher's suggestions/requests/questions included/suggested semiotic signs/tools, including verbal signs that helped the students pay attention, be aware of and objectify the adjacent and opposite angles' concepts.

Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a SingleDownwind High-Frequency Gas Sensor

EPA Science Inventory

Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a Single Downwind High-Frequency Gas Sensor With the tremendous advances in onshore oil and gas exploration and production (E&P) capability comes the realization that new tools are needed to support env...

Atmospheric measurement of point source fossil CO2 emissions

NASA Astrophysics Data System (ADS)

Turnbull, J. C.; Keller, E. D.; Baisden, T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

2014-05-01

We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m above ground level. We also determined the surface CO2ff content averaged over several weeks from the 14C content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~ one week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14C sampling strategies.

The establishment and use of the point source catalog database of the 2MASS near infrared survey

NASA Astrophysics Data System (ADS)

Gao, Y. F.; Shan, H. G.; Cheng, D.

2003-02-01

The 2MASS near infrared survey project is introduced briefly. The 2MASS point sources catalog (2MASS PSC) database and the network query system are established by using the PHP Hypertext Preprocessor and MySQL database server. By using the system, one can not only query information of sources listed in the catalog, but also draw the plots related. Moreover, after the 2MASS data are diagnosed , some research fields which can be benefited from this database are suggested.

Evidence suggesting a point source exposure in an outbreak of bovine abortion due to neosporosis.

PubMed

McAllister, M M; Huffman, E M; Hietala, S K; Conrad, P A; Anderson, M L; Salman, M D

1996-07-01

A Holstein dairy farm suffered an abortion outbreak due to neosporosis. Abortion losses were > 18%. Cows with the highest Neospora antibody titers were at the greatest risk of aborting. Mummified fetuses were found after the 43rd day of the outbreak. The epidemic curve was suggestive of a point source exposure, which is consistent with the hypothesis that Neospora can be spread by a definitive host.

Phytoparasitic Nematodes Adjacent to Established Strawberry Plantations

PubMed Central

Crow, R. V.; MacDonald, D. H.

1978-01-01

Plant-nematode populations associated with uncultivated vegetation, adjacent strawberry plants, and alternate crop sites were studied at three locations in Minnesota. At one site (Forest Lake), Paratylenchus projectus, Meloidogyne hapla, and Pratylenchus tenuis were frequently associated with the roots of native vegetation. These nematode species were also present in adjacent strawberry beds. Among alternate crops observed, oats and muskmelon usually supported the fewest nematodes although moderate densities of Xiphinema americanum and P. tenuis were found at one location in plots planted to oats. Pratylenchus tenuis was also found on rye at one location. PMID:19305841

The tiger beetles (Coleoptera, Carabidae, Cicindelinae) of Israel and adjacent lands

PubMed Central

Matalin, Andrey V.; Chikatunov, Vladimir I.

2016-01-01

Abstract Based on field studies, museums collections and literature sources, the current knowledge of the tiger beetle fauna of Israel and adjacent lands is presented. In Israel eight species occur, one of them with two subspecies, while in the Sinai Peninsula nine species of tiger beetles are now known. In the combined regions seven genera from two tribes were found. The Rift Valley with six cicindelids species is the most specious region of Israel. Cylindera contorta valdenbergi and Cicindela javeti azari have localized distributions and should be considered regional endemics. A similarity analysis of the tiger beetles faunas of different regions of Israel and the Sinai Peninsula reveal two clusters of species. The first includes the Great Rift Valley and most parts of the Sinai Peninsula, and the second incorporates most regions of Israel together with Central Sinai Foothills. Five distinct adult phenological groups of tiger beetles can be distinguished in these two clusters: active all-year (three species), spring-fall (five species), summer (two species), spring-summer (one species) and spring (one species). The likely origins of the tiger beetle fauna of this area are presented. An annotated list and illustrated identification key of the Cicindelinae of Israel and adjacent lands are provided. PMID:27110198

Forest adjacent households' voices on their perceptions and adaptation strategies to climate change in Kilombero District, Tanzania.

PubMed

Balama, Chelestino; Augustino, Suzana; Eriksen, Siri; Makonda, Fortunatus B S

2016-01-01

Climate change is a global and local challenge to both sustainable livelihoods and economic development. Tanzania as other countries of the world has been affected. Several studies have been conducted on farmers' perceptions and adaptation to climate change in the country, but little attention has been devoted to forest adjacent households in humid areas. This study assessed this gap through assessing forest adjacent households' voices on perceptions and adaptation strategies to climate change in Kilombero District, Tanzania. Data collection involved key informant interviews, focus group discussions and household questionnaires. Results showed that the majority of households perceived changed climate in terms of temperature increase, unpredictable rainfall, frequent occurrence of floods, increased dry spells during rainy season coupled with decreased water sources and emergence of new pests and diseases. The perceived change in climate has impacted agriculture productivity as the main livelihood source. Different coping and adaptation strategies are employed. These are; crop diversification, changing cropping calendar, adopting modern farming technologies, and increasing reliance on non-timber forest products. These strategies were positively and significantly influenced by socio-economic factors including household size, residence period, land ownership and household income. The study concludes that, there are changes in climatic conditions; and to respond to these climatic changes, forest adjacent households have developed numerous coping and adaptation strategies, which were positively and significantly influenced by some socio-economic factors. The study calls for actual implementation of local climate change policies and strategies in order to enhance adaptive capacity at household level.

Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources

DOEpatents

Vail, W.B. III.

1991-08-27

Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation. 9 figures.

Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources

DOEpatents

Vail, III, William B.

1991-01-01

Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.

Dynamic Control of Particle Deposition in Evaporating Droplets by an External Point Source of Vapor

PubMed Central

2018-01-01

The deposition of particles on a surface by an evaporating sessile droplet is important for phenomena as diverse as printing, thin-film deposition, and self-assembly. The shape of the final deposit depends on the flows within the droplet during evaporation. These flows are typically determined at the onset of the process by the intrinsic physical, chemical, and geometrical properties of the droplet and its environment. Here, we demonstrate deterministic emergence and real-time control of Marangoni flows within the evaporating droplet by an external point source of vapor. By varying the source location, we can modulate these flows in space and time to pattern colloids on surfaces in a controllable manner. PMID:29363979

Dynamic Control of Particle Deposition in Evaporating Droplets by an External Point Source of Vapor.

PubMed

Malinowski, Robert; Volpe, Giovanni; Parkin, Ivan P; Volpe, Giorgio

2018-02-01

The deposition of particles on a surface by an evaporating sessile droplet is important for phenomena as diverse as printing, thin-film deposition, and self-assembly. The shape of the final deposit depends on the flows within the droplet during evaporation. These flows are typically determined at the onset of the process by the intrinsic physical, chemical, and geometrical properties of the droplet and its environment. Here, we demonstrate deterministic emergence and real-time control of Marangoni flows within the evaporating droplet by an external point source of vapor. By varying the source location, we can modulate these flows in space and time to pattern colloids on surfaces in a controllable manner.

Scaled SFS method for Lambertian surface 3D measurement under point source lighting.

PubMed

Ma, Long; Lyu, Yi; Pei, Xin; Hu, Yan Min; Sun, Feng Ming

2018-05-28

A Lambertian surface is a kind of very important assumption in shape from shading (SFS), which is widely used in many measurement cases. In this paper, a novel scaled SFS method is developed to measure the shape of a Lambertian surface with dimensions. In which, a more accurate light source model is investigated under the illumination of a simple point light source, the relationship between surface depth map and the recorded image grayscale is established by introducing the camera matrix into the model. Together with the constraints of brightness, smoothness and integrability, the surface shape with dimensions can be obtained by analyzing only one image using the scaled SFS method. The algorithm simulations show a perfect matching between the simulated structures and the results, the rebuilding root mean square error (RMSE) is below 0.6mm. Further experiment is performed by measuring a PVC tube internal surface, the overall measurement error lies below 2%.

CALUTRON ION SOURCE

DOEpatents

Brobeck, W.M.

1959-02-24

An ion source is described wherein a portion of the filament serving as a cathode for the arc is protected from the effects of non-ionized particles escaping from the ionizing mechanism. In the described ion source, the source block has a gas chamber and a gas passage extending from said gas chamber to two adjacent faces of the source block. A plate overlies the passage and abuts one of the aforementioned block faces, while extending beyond the other face. In addition, the plate is apertured in line with the block passage. The filament overlies the aperture to effectively shield the portion of the filament not directiy aligned with the passage where the arc is produced.

A systematic analysis of the Braitenberg vehicle 2b for point-like stimulus sources.

PubMed

Rañó, Iñaki

2012-09-01

Braitenberg vehicles have been used experimentally for decades in robotics with limited empirical understanding. This paper presents the first mathematical model of the vehicle 2b, displaying so-called aggression behaviour, and analyses the possible trajectories for point-like smooth stimulus sources. This sensory-motor steering control mechanism is used to implement biologically grounded target approach, target-seeking or obstacle-avoidance behaviour. However, the analysis of the resulting model reveals that complex and unexpected trajectories can result even for point-like stimuli. We also prove how the implementation of the controller and the vehicle morphology interact to affect the behaviour of the vehicle. This work provides a better understanding of Braitenberg vehicle 2b, explains experimental results and paves the way for a formally grounded application on robotics as well as for a new way of understanding target seeking in biology.

A fast and fully automatic registration approach based on point features for multi-source remote-sensing images

NASA Astrophysics Data System (ADS)

Yu, Le; Zhang, Dengrong; Holden, Eun-Jung

2008-07-01

Automatic registration of multi-source remote-sensing images is a difficult task as it must deal with the varying illuminations and resolutions of the images, different perspectives and the local deformations within the images. This paper proposes a fully automatic and fast non-rigid image registration technique that addresses those issues. The proposed technique performs a pre-registration process that coarsely aligns the input image to the reference image by automatically detecting their matching points by using the scale invariant feature transform (SIFT) method and an affine transformation model. Once the coarse registration is completed, it performs a fine-scale registration process based on a piecewise linear transformation technique using feature points that are detected by the Harris corner detector. The registration process firstly finds in succession, tie point pairs between the input and the reference image by detecting Harris corners and applying a cross-matching strategy based on a wavelet pyramid for a fast search speed. Tie point pairs with large errors are pruned by an error-checking step. The input image is then rectified by using triangulated irregular networks (TINs) to deal with irregular local deformations caused by the fluctuation of the terrain. For each triangular facet of the TIN, affine transformations are estimated and applied for rectification. Experiments with Quickbird, SPOT5, SPOT4, TM remote-sensing images of the Hangzhou area in China demonstrate the efficiency and the accuracy of the proposed technique for multi-source remote-sensing image registration.

Disc replacement adjacent to cervical fusion: a biomechanical comparison of hybrid construct versus two-level fusion.

PubMed

Lee, Michael J; Dumonski, Mark; Phillips, Frank M; Voronov, Leonard I; Renner, Susan M; Carandang, Gerard; Havey, Robert M; Patwardhan, Avinash G

2011-11-01

A cadaveric biomechanical study. To investigate the biomechanical behavior of the cervical spine after cervical total disc replacement (TDR) adjacent to a fusion as compared to a two-level fusion. There are concerns regarding the biomechanical effects of cervical fusion on the mobile motion segments. Although previous biomechanical studies have demonstrated that cervical disc replacement normalizes adjacent segment motion, there is a little information regarding the function of a cervical disc replacement adjacent to an anterior cervical decompression and fusion, a potentially common clinical application. Nine cadaveric cervical spines (C3-T1, age: 60.2 ± 3.5 years) were tested under load- and displacement-control testing. After intact testing, a simulated fusion was performed at C4-C5, followed by C6-C7. The simulated fusion was then reversed, and the response of TDR at C5-C6 was measured. A hybrid construct was then tested with the TDR either below or above a single-level fusion and contrasted with a simulated two-level fusion (C4-C6 and C5-C7). The external fixator device used to simulate fusion significantly reduced range of motion (ROM) at C4-C5 and C6-C7 by 74.7 ± 8.1% and 78.1 ± 11.5%, respectively (P < 0.05). Removal of the fusion construct restored the motion response of the spinal segments to their intact state. Arthroplasty performed at C5-C6 using the porous-coated motion disc prosthesis maintained the total flexion-extension ROM to the level of the intact controls when used as a stand-alone procedure or when implanted adjacent to a single-level fusion (P > 0.05). The location of the single-level fusion, whether above or below the arthroplasty, did not significantly affect the motion response of the arthroplasty in the hybrid construct. Performing a two-level fusion significantly increased the motion demands on the nonoperated segments as compared to a hybrid TDR-plus fusion construct when the spine was required to reach the same motion end points

Calculations of the electrostatic potential adjacent to model phospholipid bilayers.

PubMed Central

Peitzsch, R M; Eisenberg, M; Sharp, K A; McLaughlin, S

1995-01-01

We used the nonlinear Poisson-Boltzmann equation to calculate electrostatic potentials in the aqueous phase adjacent to model phospholipid bilayers containing mixtures of zwitterionic lipids (phosphatidylcholine) and acidic lipids (phosphatidylserine or phosphatidylglycerol). The aqueous phase (relative permittivity, epsilon r = 80) contains 0.1 M monovalent salt. When the bilayers contain < 11% acidic lipid, the -25 mV equipotential surfaces are discrete domes centered over the negatively charged lipids and are approximately twice the value calculated using Debye-Hückel theory. When the bilayers contain > 25% acidic lipid, the -25 mV equipotential profiles are essentially flat and agree well with the values calculated using Gouy-Chapman theory. When the bilayers contain 100% acidic lipid, all of the equipotential surfaces are flat and agree with Gouy-Chapman predictions (including the -100 mV surface, which is located only 1 A from the outermost atoms). Even our model bilayers are not simple systems: the charge on each lipid is distributed over several atoms, these partial charges are non-coplanar, there is a 2 A ion-exclusion region (epsilon r = 80) adjacent to the polar headgroups, and the molecular surface is rough. We investigated the effect of these four factors using smooth (or bumpy) epsilon r = 2 slabs with embedded point charges: these factors had only minor effects on the potential in the aqueous phase. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 PMID:7756540

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

NASA Astrophysics Data System (ADS)

Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

2018-06-01

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

Identification of Geologic and Anthropogenic Sources of Phosphorus to Streams in California and Portions of Adjacent States, U.S.A., Using SPARROW Modeling

NASA Astrophysics Data System (ADS)

Domagalski, J. L.

2013-12-01

The SPARROW (Spatially Referenced Regressions On Watershed Attributes) model allows for the simulation of nutrient transport at un-gauged catchments on a regional scale. The model was used to understand natural and anthropogenic factors affecting phosphorus transport in developed, undeveloped, and mixed watersheds. The SPARROW model is a statistical tool that allows for mass balance calculation of constituent sources, transport, and aquatic decay based upon a calibration of a subset of stream networks, where concentrations and discharge have been measured. Calibration is accomplished using potential sources for a given year and may include fertilizer, geological background (based on bed-sediment samples and aggregated with geochemical map units), point source discharge, and land use categories. NHD Plus version 2 was used to model the hydrologic system. Land to water transport variables tested were precipitation, permeability, soil type, tile drains, and irrigation. For this study area, point sources, cultivated land, and geological background are significant phosphorus sources to streams. Precipitation and clay content of soil are significant land to water transport variables and various stream sizes show significance with respect to aquatic decay. Specific rock types result in different levels of phosphorus loading and watershed yield. Some important geological sources are volcanic rocks (andesite and basalt), granodiorite, glacial deposits, and Mesozoic to Cenozoic marine deposits. Marine sediments vary in their phosphorus content, but are responsible for some of the highest natural phosphorus yields, especially along the Central and Southern California coast. The Miocene Monterey Formation was found to be an especially important local source in southern California. In contrast, mixed metamorphic and igneous assemblages such as argillites, peridotite, and shales of the Trinity Mountains of northern California result in some of the lowest phosphorus yields. The

Analysis of the different source terms of natural radionuclides in a river affected by NORM (Naturally Occurring Radioactive Materials) activities.

PubMed

Baeza, A; Corbacho, J A; Guillén, J; Salas, A; Mora, J C

2011-05-01

The present work studied the radioacitivity impact of a coal-fired power plant (CFPP), a NORM industry, on the water of the Regallo river which the plant uses for cooling. Downstream, this river passes through an important irrigated farming area, and it is a tributary of the Ebro, one of Spain's largest rivers. Although no alteration of the (210)Po or (232)Th content was detected, the (234,238)U and (226)Ra contents of the water were significantly greater immediately below CFPP's discharge point. The (226)Ra concentration decreased progressively downstream from the discharge point, but the uranium content increased significantly again at two sampling points 8 km downstream from the CFPP's effluent. This suggested the presence of another, unexpected uranium source term different from the CFPP. The input from this second uranium source term was even greater than that from the CFPP. Different hypotheses were tested (a reservoir used for irrigation, remobilization from sediments, and the effect of fertilizers used in the area), with it finally being demonstrated that the source was the fertilizers used in the adjacent farming areas. Copyright © 2011 Elsevier Ltd. All rights reserved.

40 CFR 414.91 - Toxic pollutant effluent limitations and standards for direct discharge point sources that use...

Code of Federal Regulations, 2011 CFR

2011-07-01

... AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources That...(k)fluoranthene 59 22 Benzo(a)pyrene 61 23 Bis(2-ethylhexyl) phthalate 279 103 Carbon Tetrachloride... Zinc for Rayon Fiber Manufacture that uses the viscose process and Acrylic Fiber Manufacture that uses...

40 CFR 414.91 - Toxic pollutant effluent limitations and standards for direct discharge point sources that use...

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources That...(k)fluoranthene 59 22 Benzo(a)pyrene 61 23 Bis(2-ethylhexyl) phthalate 279 103 Carbon Tetrachloride... Zinc for Rayon Fiber Manufacture that uses the viscose process and Acrylic Fiber Manufacture that uses...

Variable length adjacent partitioning for PTS based PAPR reduction of OFDM signal

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

Ibraheem, Zeyid T.; Rahman, Md. Mijanur; Yaakob, S. N.

2015-05-15

Peak-to-Average power ratio (PAPR) is a major drawback in OFDM communication. It leads the power amplifier into nonlinear region operation resulting into loss of data integrity. As such, there is a strong motivation to find techniques to reduce PAPR. Partial Transmit Sequence (PTS) is an attractive scheme for this purpose. Judicious partitioning the OFDM data frame into disjoint subsets is a pivotal component of any PTS scheme. Out of the existing partitioning techniques, adjacent partitioning is characterized by an attractive trade-off between cost and performance. With an aim of determining effects of length variability of adjacent partitions, we performed anmore » investigation into the performances of a variable length adjacent partitioning (VL-AP) and fixed length adjacent partitioning in comparison with other partitioning schemes such as pseudorandom partitioning. Simulation results with different modulation and partitioning scenarios showed that fixed length adjacent partition had better performance compared to variable length adjacent partitioning. As expected, simulation results showed a slightly better performance of pseudorandom partitioning technique compared to fixed and variable adjacent partitioning schemes. However, as the pseudorandom technique incurs high computational complexities, adjacent partitioning schemes were still seen as favorable candidates for PAPR reduction.« less

Isotopic Tracers for Delineating Non-Point Source Pollutants in Surface Water

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

Davisson, M L

2001-03-01

This study tested whether isotope measurements of surface water and dissolved constituents in surface water could be used as tracers of non-point source pollution. Oxygen-18 was used as a water tracer, while carbon-14, carbon-13, and deuterium were tested as tracers of DOC. Carbon-14 and carbon-13 were also used as tracers of dissolved inorganic carbon, and chlorine-36 and uranium isotopes were tested as tracers of other dissolved salts. In addition, large databases of water quality measurements were assembled for the Missouri River at St. Louis and the Sacramento-San Joaquin Delta in California to enhance interpretive results of the isotope measurements. Muchmore » of the water quality data has been under-interpreted and provides a valuable resource to investigative research, for which this report exploits and integrates with the isotope measurements.« less

Contaminant point source localization error estimates as functions of data quantity and model quality

NASA Astrophysics Data System (ADS)

Hansen, Scott K.; Vesselinov, Velimir V.

2016-10-01

We develop empirically-grounded error envelopes for localization of a point contamination release event in the saturated zone of a previously uncharacterized heterogeneous aquifer into which a number of plume-intercepting wells have been drilled. We assume that flow direction in the aquifer is known exactly and velocity is known to within a factor of two of our best guess from well observations prior to source identification. Other aquifer and source parameters must be estimated by interpretation of well breakthrough data via the advection-dispersion equation. We employ high performance computing to generate numerous random realizations of aquifer parameters and well locations, simulate well breakthrough data, and then employ unsupervised machine optimization techniques to estimate the most likely spatial (or space-time) location of the source. Tabulating the accuracy of these estimates from the multiple realizations, we relate the size of 90% and 95% confidence envelopes to the data quantity (number of wells) and model quality (fidelity of ADE interpretation model to actual concentrations in a heterogeneous aquifer with channelized flow). We find that for purely spatial localization of the contaminant source, increased data quantities can make up for reduced model quality. For space-time localization, we find similar qualitative behavior, but significantly degraded spatial localization reliability and less improvement from extra data collection. Since the space-time source localization problem is much more challenging, we also tried a multiple-initial-guess optimization strategy. This greatly enhanced performance, but gains from additional data collection remained limited.

Fast computation of quadrupole and hexadecapole approximations in microlensing with a single point-source evaluation

NASA Astrophysics Data System (ADS)

Cassan, Arnaud

2017-07-01

The exoplanet detection rate from gravitational microlensing has grown significantly in recent years thanks to a great enhancement of resources and improved observational strategy. Current observatories include ground-based wide-field and/or robotic world-wide networks of telescopes, as well as space-based observatories such as satellites Spitzer or Kepler/K2. This results in a large quantity of data to be processed and analysed, which is a challenge for modelling codes because of the complexity of the parameter space to be explored and the intensive computations required to evaluate the models. In this work, I present a method that allows to compute the quadrupole and hexadecapole approximations of the finite-source magnification with more efficiency than previously available codes, with routines about six times and four times faster, respectively. The quadrupole takes just about twice the time of a point-source evaluation, which advocates for generalizing its use to large portions of the light curves. The corresponding routines are available as open-source python codes.

Performance summary on a high power dense plasma focus x-ray lithography point source producing 70 nm line features in AlGaAs microcircuits

NASA Astrophysics Data System (ADS)

Petr, Rodney; Bykanov, Alexander; Freshman, Jay; Reilly, Dennis; Mangano, Joseph; Roche, Maureen; Dickenson, Jason; Burte, Mitchell; Heaton, John

2004-08-01

A high average power dense plasma focus (DPF), x-ray point source has been used to produce ˜70 nm line features in AlGaAs-based monolithic millimeter-wave integrated circuits (MMICs). The DPF source has produced up to 12 J per pulse of x-ray energy into 4π steradians at ˜1 keV effective wavelength in ˜2 Torr neon at pulse repetition rates up to 60 Hz, with an effective x-ray yield efficiency of ˜0.8%. Plasma temperature and electron concentration are estimated from the x-ray spectrum to be ˜170 eV and ˜5.1019 cm-3, respectively. The x-ray point source utilizes solid-state pulse power technology to extend the operating lifetime of electrodes and insulators in the DPF discharge. By eliminating current reversals in the DPF head, an anode electrode has demonstrated a lifetime of more than 5 million shots. The x-ray point source has also been operated continuously for 8 h run times at 27 Hz average pulse recurrent frequency. Measurements of shock waves produced by the plasma discharge indicate that overpressure pulses must be attenuated before a collimator can be integrated with the DPF point source.

Long-term effects of vertebroplasty: adjacent vertebral fractures.

PubMed

Baroud, Gamal; Vant, Christianne; Wilcox, Ruth

2006-01-01

In today's aging population, osteoporosis-related fractures are an ever-growing concern. Vertebroplasty, a promising yet cost-effective treatment for vertebral compression fractures, has an increasing role. The first vertebroplasty procedures were reported by Deramond and Galibert in France in 1987, and international interest grew with continued development of clinical techniques and augmentation materials in Europe and the United States. Initial publications and presentations at peer review meetings demonstrated 60-90% success rates in providing immediate and significant pain relief. The objective of this review is to assemble experimental and computational biomechanical research whose goal is determining and preventing the negative long-term effects ofvertebroplasty, with a specific focus on adjacent vertebral fractures. Biomechanical studies using isolated cancellous bone cylinders have shown that osteoporotic cancellous bone samples augmented by the rigid bone cement were at least 12 times stiffer and 35 times stronger than the untreated osteoporotic cancellous bone samples. The biomechanical efficacy of the procedure to repair the fractured vertebrae and prevent further collapse is determined using single-vertebra models. The strength or load-bearing capacity of a single vertebra is significantly increased following augmentation when compared to the intact strength. However, there is no dear result regarding the overall stiffness of the single vertebra, with studies reporting contradictorily that the stiffness increases, decreases, or does not significantly alter following augmentation. The effects of vertebroplasty on adjacent structures are studied via multisegment models, whose results plainly oppose the findings of the single-vertebra and intravertebral models. Here, augmentation was shown to decrease the overall segment strength by 19% when compared to the matched controls. As well, there is a significant increase in disc pressure compared to the pre

[Estimation of urban non-point source pollution loading and its factor analysis in the Pearl River Delta].

PubMed

Liao, Yi-Shan; Zhuo, Mu-Ning; Li, Ding-Qiang; Guo, Tai-Long

2013-08-01

In the Pearl Delta region, urban rivers have been seriously polluted, and the input of non-point source pollution materials, such as chemical oxygen demand (COD), into rivers cannot be neglected. During 2009-2010, the water qualities at eight different catchments in the Fenjiang River of Foshan city were monitored, and the COD loads for eight rivulet sewages were calculated in respect of different rainfall conditions. Interesting results were concluded in our paper. The rainfall and landuse type played important roles in the COD loading, with greater influence of rainfall than landuse type. Consequently, a COD loading formula was constructed that was defined as a function of runoff and landuse type that were derived SCS model and land use map. Loading of COD could be evaluated and predicted with the constructed formula. The mean simulation accuracy for single rainfall event was 75.51%. Long-term simulation accuracy was better than that of single rainfall. In 2009, the estimated COD loading and its loading intensity were 8 053 t and 339 kg x (hm2 x a)(-1), and the industrial land was regarded as the main source of COD pollution area. The severe non-point source pollution such as COD in Fenjiang River must be paid more attention in the future.

33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Naval Base Point... Guard District § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA. (a) Location. The following area is a security zone: The water adjacent to the Naval Base Point Loma, San Diego...

An Ultradeep Chandra Catalog of X-Ray Point Sources in the Galactic Center Star Cluster

NASA Astrophysics Data System (ADS)

Zhu, Zhenlin; Li, Zhiyuan; Morris, Mark R.

2018-04-01

We present an updated catalog of X-ray point sources in the inner 500″ (∼20 pc) of the Galactic center (GC), where the nuclear star cluster (NSC) stands, based on a total of ∼4.5 Ms of Chandra observations taken from 1999 September to 2013 April. This ultradeep data set offers unprecedented sensitivity for detecting X-ray sources in the GC, down to an intrinsic 2–10 keV luminosity of 1.0 × 1031 erg s‑1. A total of 3619 sources are detected in the 2–8 keV band, among which ∼3500 are probable GC sources and ∼1300 are new identifications. The GC sources collectively account for ∼20% of the total 2–8 keV flux from the inner 250″ region where detection sensitivity is the greatest. Taking advantage of this unprecedented sample of faint X-ray sources that primarily traces the old stellar populations in the NSC, we revisit global source properties, including long-term variability, cumulative spectra, luminosity function, and spatial distribution. Based on the equivalent width and relative strength of the iron lines, we suggest that in addition to the arguably predominant population of magnetic cataclysmic variables (CVs), nonmagnetic CVs contribute substantially to the detected sources, especially in the lower-luminosity group. On the other hand, the X-ray sources have a radial distribution closely following the stellar mass distribution in the NSC, but much flatter than that of the known X-ray transients, which are presumably low-mass X-ray binaries (LMXBs) caught in outburst. This, together with the very modest long-term variability of the detected sources, strongly suggests that quiescent LMXBs are a minor (less than a few percent) population.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Astrophysics Data System (ADS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-05-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (LX ) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (Γ), hardness ratios, and LX , in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L X, 0.5-8.0 keV >1042 erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known αOX-νL ν (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the "non-AGN locus" in αOX-νL ν (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR <= -20 and L X, 0.5-8.0 keV >=1041 erg s-1 is 0.08^{+0.35}_{-0.01}, somewhat higher than the ~5% fraction in galaxy clusters.

Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China

USGS Publications Warehouse

Wu, Yiping; Chen, Ji

2013-01-01

Understanding the physical processes of point source (PS) and nonpoint source (NPS) pollution is critical to evaluate river water quality and identify major pollutant sources in a watershed. In this study, we used the physically-based hydrological/water quality model, Soil and Water Assessment Tool, to investigate the influence of PS and NPS pollution on the water quality of the East River (Dongjiang in Chinese) in southern China. Our results indicate that NPS pollution was the dominant contribution (>94%) to nutrient loads except for mineral phosphorus (50%). A comprehensive Water Quality Index (WQI) computed using eight key water quality variables demonstrates that water quality is better upstream than downstream despite the higher level of ammonium nitrogen found in upstream waters. Also, the temporal (seasonal) and spatial distributions of nutrient loads clearly indicate the critical time period (from late dry season to early wet season) and pollution source areas within the basin (middle and downstream agricultural lands), which resource managers can use to accomplish substantial reduction of NPS pollutant loadings. Overall, this study helps our understanding of the relationship between human activities and pollutant loads and further contributes to decision support for local watershed managers to protect water quality in this region. In particular, the methods presented such as integrating WQI with watershed modeling and identifying the critical time period and pollutions source areas can be valuable for other researchers worldwide.

33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, CA.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Loma; San Diego Bay, CA. 165.1102 Section 165.1102 Navigation and Navigable Waters COAST GUARD... § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, CA. (a) Location. The following area is a security zone: The water adjacent to the Naval Base Point Loma, San Diego, CA, enclosed by the...

Analysis of the environmental behavior of farmers for non-point source pollution control and management in a water source protection area in China.

PubMed

Wang, Yandong; Yang, Jun; Liang, Jiping; Qiang, Yanfang; Fang, Shanqi; Gao, Minxue; Fan, Xiaoyu; Yang, Gaihe; Zhang, Baowen; Feng, Yongzhong

2018-08-15

The environmental behavior of farmers plays an important role in exploring the causes of non-point source pollution and taking scientific control and management measures. Based on the theory of planned behavior (TPB), the present study investigated the environmental behavior of farmers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China. Results showed that TPB could explain farmers' environmental behavior (SMC=0.26) and intention (SMC=0.36) well. Furthermore, the farmers' attitude towards behavior (AB), subjective norm (SN), and perceived behavioral control (PBC) positively and significantly influenced their environmental intention; their environmental intention further impacted their behavior. SN was proved to be the main key factor indirectly influencing the farmers' environmental behavior, while PBC had no significant and direct effect. Moreover, environmental knowledge following as a moderator, gender and age was used as control variables to conduct the environmental knowledge on TPB construct moderated mediation analysis. It demonstrated that gender had a significant controlling effect on environmental behavior; that is, males engage in more environmentally friendly behaviors. However, age showed a significant negative controlling effect on pro-environmental intention and an opposite effect on pro-environmental behavior. In addition, environmental knowledge could negatively moderate the relationship between PBC and environmental intention. PBC had a greater impact on the environmental intention of farmers with poor environmental knowledge, compared to those with plenty environmental knowledge. Altogether, the present study could provide a theoretical basis for non-point source pollution control and management. Copyright © 2018 Elsevier B.V. All rights reserved.

Explaining large mortality differences between adjacent counties: a cross-sectional study.

PubMed

Schootman, M; Chien, L; Yun, S; Pruitt, S L

2016-08-02

Extensive geographic variation in adverse health outcomes exists, but global measures ignore differences between adjacent geographic areas, which often have very different mortality rates. We describe a novel application of advanced spatial analysis to 1) examine the extent of differences in mortality rates between adjacent counties, 2) describe differences in risk factors between adjacent counties, and 3) determine if differences in risk factors account for the differences in mortality rates between adjacent counties. We conducted a cross-sectional study in Missouri, USA with 2005-2009 age-adjusted all-cause mortality rate as the outcome and county-level explanatory variables from a 2007 population-based survey. We used a multi-level Gaussian model and a full Bayesian approach to analyze the difference in risk factors relative to the difference in mortality rates between adjacent counties. The average mean difference in the age-adjusted mortality rate between any two adjacent counties was -3.27 (standard deviation = 95.5) per 100,000 population (maximum = 258.80). Six variables were associated with mortality differences: inability to obtain medical care because of cost (β = 2.6), hospital discharge rate (β = 1.03), prevalence of fair/poor health (β = 2.93), and hypertension (β = 4.75) and poverty prevalence (β = 6.08). Examining differences in mortality rates and associated risk factors between adjacent counties provides additional insight for future interventions to reduce geographic disparities.

SEARCHES FOR POINT-LIKE AND EXTENDED NEUTRINO SOURCES CLOSE TO THE GALACTIC CENTER USING THE ANTARES NEUTRINO TELESCOPE

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

Adrián-Martínez, S.; Ardid, M.; Bou-Cabo, M.

2014-05-01

A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. = –46.°8 and decl. = –64.°9 and corresponds to a 2.2σ background fluctuation. In addition, upper limits on the flux normalization of an E {sup –2} muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close tomore » the Galactic Center in the recently reported neutrino sample of the IceCube telescope, a search for point sources in a broad region around this accumulation has been carried out. No indication of a neutrino signal has been found in the ANTARES data and upper limits on the flux normalization of an E {sup –2} energy spectrum of neutrinos from point sources in that region have been set. The 90% confidence level upper limits on the muon neutrino flux normalization vary between 3.5 and 5.1 × 10{sup –8} GeV cm{sup –2} s{sup –1}, depending on the exact location of the source.« less

Industrial point source CO2 emission strength estimation with aircraft measurements and dispersion modelling.

PubMed

Carotenuto, Federico; Gualtieri, Giovanni; Miglietta, Franco; Riccio, Angelo; Toscano, Piero; Wohlfahrt, Georg; Gioli, Beniamino

2018-02-22

CO 2 remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO 2 emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO 2 industrial point source, located in Biganos, France. CO 2 density measurements were obtained by applying the mass balance method, while CO 2 emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.

Pre-coding method and apparatus for multiple source or time-shifted single source data and corresponding inverse post-decoding method and apparatus

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu (Inventor)

1997-01-01

A pre-coding method and device for improving data compression performance by removing correlation between a first original data set and a second original data set, each having M members, respectively. The pre-coding method produces a compression-efficiency-enhancing double-difference data set. The method and device produce a double-difference data set, i.e., an adjacent-delta calculation performed on a cross-delta data set or a cross-delta calculation performed on two adjacent-delta data sets, from either one of (1) two adjacent spectral bands coming from two discrete sources, respectively, or (2) two time-shifted data sets coming from a single source. The resulting double-difference data set is then coded using either a distortionless data encoding scheme (entropy encoding) or a lossy data compression scheme. Also, a post-decoding method and device for recovering a second original data set having been represented by such a double-difference data set.

Pre-coding method and apparatus for multiple source or time-shifted single source data and corresponding inverse post-decoding method and apparatus

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu (Inventor)

1998-01-01

A pre-coding method and device for improving data compression performance by removing correlation between a first original data set and a second original data set, each having M members, respectively. The pre-coding method produces a compression-efficiency-enhancing double-difference data set. The method and device produce a double-difference data set, i.e., an adjacent-delta calculation performed on a cross-delta data set or a cross-delta calculation performed on two adjacent-delta data sets, from either one of (1) two adjacent spectral bands coming from two discrete sources, respectively, or (2) two time-shifted data sets coming from a single source. The resulting double-difference data set is then coded using either a distortionless data encoding scheme (entropy encoding) or a lossy data compression scheme. Also, a post-decoding method and device for recovering a second original data set having been represented by such a double-difference data set.

Local adjacency metric dimension of sun graph and stacked book graph

NASA Astrophysics Data System (ADS)

Yulisda Badri, Alifiah; Darmaji

2018-03-01

A graph is a mathematical system consisting of a non-empty set of nodes and a set of empty sides. One of the topics to be studied in graph theory is the metric dimension. Application in the metric dimension is the navigation robot system on a path. Robot moves from one vertex to another vertex in the field by minimizing the errors that occur in translating the instructions (code) obtained from the vertices of that location. To move the robot must give different instructions (code). In order for the robot to move efficiently, the robot must be fast to translate the code of the nodes of the location it passes. so that the location vertex has a minimum distance. However, if the robot must move with the vertex location on a very large field, so the robot can not detect because the distance is too far.[6] In this case, the robot can determine its position by utilizing location vertices based on adjacency. The problem is to find the minimum cardinality of the required location vertex, and where to put, so that the robot can determine its location. The solution to this problem is the dimension of adjacency metric and adjacency metric bases. Rodrguez-Velzquez and Fernau combine the adjacency metric dimensions with local metric dimensions, thus becoming the local adjacency metric dimension. In the local adjacency metric dimension each vertex in the graph may have the same adjacency representation as the terms of the vertices. To obtain the local metric dimension of values in the graph of the Sun and the stacked book graph is used the construction method by considering the representation of each adjacent vertex of the graph.

Constrained and Unconstrained Partial Adjacent Category Logit Models for Ordinal Response Variables

ERIC Educational Resources Information Center

Fullerton, Andrew S.; Xu, Jun

2018-01-01

Adjacent category logit models are ordered regression models that focus on comparisons of adjacent categories. These models are particularly useful for ordinal response variables with categories that are of substantive interest. In this article, we consider unconstrained and constrained versions of the partial adjacent category logit model, which…

Volatile organic compound emissions from the oil and natural gas industry in the Uinta Basin, Utah: point sources compared to ambient air composition

NASA Astrophysics Data System (ADS)

Warneke, C.; Geiger, F.; Edwards, P. M.; Dube, W.; Pétron, G.; Kofler, J.; Zahn, A.; Brown, S. S.; Graus, M.; Gilman, J.; Lerner, B.; Peischl, J.; Ryerson, T. B.; de Gouw, J. A.; Roberts, J. M.

2014-05-01

The emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uinta Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas wells using dry-gas collection, which means dehydration happens at the well, were clearly associated with higher mixing ratios than other wells. Another large source was the flowback pond near a recently hydraulically re-fractured gas well. The comparison of the VOC composition of the emissions from the oil and natural gas wells showed that wet gas collection wells compared well with the majority of the data at Horse Pool and that oil wells compared well with the rest of the ground site data. Oil wells on average emit heavier compounds than gas wells. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings.

Contaminant point source localization error estimates as functions of data quantity and model quality

DOE PAGES

Hansen, Scott K.; Vesselinov, Velimir Valentinov

2016-10-01

We develop empirically-grounded error envelopes for localization of a point contamination release event in the saturated zone of a previously uncharacterized heterogeneous aquifer into which a number of plume-intercepting wells have been drilled. We assume that flow direction in the aquifer is known exactly and velocity is known to within a factor of two of our best guess from well observations prior to source identification. Other aquifer and source parameters must be estimated by interpretation of well breakthrough data via the advection-dispersion equation. We employ high performance computing to generate numerous random realizations of aquifer parameters and well locations, simulatemore » well breakthrough data, and then employ unsupervised machine optimization techniques to estimate the most likely spatial (or space-time) location of the source. Tabulating the accuracy of these estimates from the multiple realizations, we relate the size of 90% and 95% confidence envelopes to the data quantity (number of wells) and model quality (fidelity of ADE interpretation model to actual concentrations in a heterogeneous aquifer with channelized flow). We find that for purely spatial localization of the contaminant source, increased data quantities can make up for reduced model quality. For space-time localization, we find similar qualitative behavior, but significantly degraded spatial localization reliability and less improvement from extra data collection. Since the space-time source localization problem is much more challenging, we also tried a multiple-initial-guess optimization strategy. Furthermore, this greatly enhanced performance, but gains from additional data collection remained limited.« less

Statistical Measurement of the Gamma-Ray Source-count Distribution as a Function of Energy

NASA Astrophysics Data System (ADS)

Zechlin, Hannes-S.; Cuoco, Alessandro; Donato, Fiorenza; Fornengo, Nicolao; Regis, Marco

2016-08-01

Statistical properties of photon count maps have recently been proven as a new tool to study the composition of the gamma-ray sky with high precision. We employ the 1-point probability distribution function of six years of Fermi-LAT data to measure the source-count distribution dN/dS and the diffuse components of the high-latitude gamma-ray sky as a function of energy. To that aim, we analyze the gamma-ray emission in five adjacent energy bands between 1 and 171 GeV. It is demonstrated that the source-count distribution as a function of flux is compatible with a broken power law up to energies of ˜50 GeV. The index below the break is between 1.95 and 2.0. For higher energies, a simple power-law fits the data, with an index of {2.2}-0.3+0.7 in the energy band between 50 and 171 GeV. Upper limits on further possible breaks as well as the angular power of unresolved sources are derived. We find that point-source populations probed by this method can explain {83}-13+7% ({81}-19+52%) of the extragalactic gamma-ray background between 1.04 and 1.99 GeV (50 and 171 GeV). The method has excellent capabilities for constraining the gamma-ray luminosity function and the spectra of unresolved blazars.

Wave propagation in anisotropic medium due to an oscillatory point source with application to unidirectional composites

NASA Technical Reports Server (NTRS)

Williams, J. H., Jr.; Marques, E. R. C.; Lee, S. S.

1986-01-01

The far-field displacements in an infinite transversely isotropic elastic medium subjected to an oscillatory concentrated force are derived. The concepts of velocity surface, slowness surface and wave surface are used to describe the geometry of the wave propagation process. It is shown that the decay of the wave amplitudes depends not only on the distance from the source (as in isotropic media) but also depends on the direction of the point of interest from the source. As an example, the displacement field is computed for a laboratory fabricated unidirectional fiberglass epoxy composite. The solution for the displacements is expressed as an amplitude distribution and is presented in polar diagrams. This analysis has potential usefulness in the acoustic emission (AE) and ultrasonic nondestructive evaluation of composite materials. For example, the transient localized disturbances which are generally associated with AE sources can be modeled via this analysis. In which case, knowledge of the displacement field which arrives at a receiving transducer allows inferences regarding the strength and orientation of the source, and consequently perhaps the degree of damage within the composite.

PIXE analysis of elements in gastric cancer and adjacent mucosa

NASA Astrophysics Data System (ADS)

Liu, Qixin; Zhong, Ming; Zhang, Xiaofeng; Yan, Lingnuo; Xu, Yongling; Ye, Simao

1990-04-01

The elemental regional distributions in 20 resected human stomach tissues were obtained using PIXE analysis. The samples were pathologically divided into four types: normal, adjacent mucosa A, adjacent mucosa B and cancer. The targets for PIXE analysis were prepared by wet digestion with a pressure bomb system. P, K, Fe, Cu, Zn and Se were measured and statistically analysed. We found significantly higher concentrations of P, K, Cu, Zn and a higher ratio of Cu compared to Zn in cancer tissue as compared with normal tissue, but statistically no significant difference between adjacent mucosa and cancer tissue was found.

Paleogeographic evolution of foldbelts adjacent to petroleum basins of Venezuela and Trinidad

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

Goodman, E.D.; Koch, P.S.; Summa, L.L.

1996-08-01

The foldbelts of Venezuela and Trinidad have shaped the history of adjacent sedimentary basins. A set of paleogeographic maps on reconstructed bases depict the role of foldbelts in the development of the sedimentary basins of Venezuela. Some of the foldbelts are inverted, pre-Tertiary graben/passive margin systems. Other foldbelts are allochthonous nappes or parautochthons that override the Mesozoic passive margin hinge without inversion. The emergence of these foldbelts changed the course of existing river systems and provided a new source for sediments and maturation in adjacent deeps. The Merida Andes area was remobilized beginning in the Early Miocene as a zonemore » of lateral shear, along which the Bonaire Block has moved over 200 km to the northeast, dismembering the Maracaibo and Barinas basins. Late Miocene to Recent transpression and fault reactivation have driven rapid Andean uplift with thrust-related subsidence and maturation (e.g., SE Maracaibo foredeep). To the east, uplift and erosion of the Serrania del Interior (1) curtailed mid-Tertiary fluvial systems flowing northward from the igneous and sedimentary rocks of the Guyana Shield, deflecting them eastward, and (2) removed the thick early Miocene foredeep fill into a younger foredeep. Thus, the fold-thrust belts and sedimentary basins in this region are linked in their evolutionary histories.« less

77 FR 19282 - Draft NPDES General Permit for Discharges From the Oil and Gas Extraction Point Source Category...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-30

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9650-8] Draft NPDES General Permit for Discharges From the Oil and Gas Extraction Point Source Category to Coastal Waters in Texas (TXG330000) AGENCY: Environmental Protection Agency (EPA). ACTION: Proposal of NPDES General Permit Renewal. SUMMARY: EPA Region 6...

Diffusion-Weighted MRI Assessment of Adjacent Disc Degeneration After Thoracolumbar Vertebral Fractures

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

Noriega, David C., E-mail: dcnoriega1970@gmail.com; Marcia, Stefano, E-mail: stemarcia@gmail.com; Ardura, Francisco, E-mail: fardura@ono.com

ObjectiveThe purpose of this study was to assess, by the mean apparent diffusion coefficient (ADC), if a relationship exists between disc ADC and MR findings of adjacent disc degeneration after thoracolumbar fractures treated by anatomic reduction using vertebral augmentation (VAP).Materials and MethodsTwenty non-consecutive patients (mean age 50.7 years; range 45–56) treated because of vertebral fractures, were included in this study. There were 10 A3.1 and 10 A1.2 fractures (AO classification). Surgical treatment using VAP was applied in 14 cases, and conservative in 6 patients. MRI T2-weighted images and mapping of apparent diffusion coefficient (ADC) of the intervertebral disc adjacent to themore » fractured segment were performed after a mean follow-up of 32 months. A total of 60 discs, 3 per patient, were analysed: infra-adjacent, supra-adjacent and a control disc one level above the supra-adjacent.ResultsNo differences between patients surgically treated and those following a conservative protocol regarding the average ADC values obtained in the 20 control discs analysed were found. Considering all discs, average ADC in the supra-adjacent level was lower than in the infra-adjacent (1.35 ± 0.12 vs. 1.53 ± 0.06; p < 0.001). Average ADC values of the discs used as a control were similar to those of the infra-adjacent level (1.54 ± 0.06). Compared to surgically treated patients, discs at the supra-adjacent fracture level showed statistically significant lower values in cases treated conservatively (p < 0.001). The variation in the delay of surgery had no influence on the average values of ADC at any of the measured levels.ConclusionsADC measurements of the supra-adjacent discs after a mean follow-up of 32 months following thoracolumbar fractures, showed that restoration of the vertebral collapse by minimally invasive VAP prevents posttraumatic disc degeneration.« less

High intensity, pulsed thermal neutron source

DOEpatents

Carpenter, J.M.

1973-12-11

This invention relates to a high intensity, pulsed thermal neutron source comprising a neutron-producing source which emits pulses of fast neutrons, a moderator block adjacent to the last neutron source, a reflector block which encases the fast neutron source and the moderator block and has a thermal neutron exit port extending therethrough from the moderator block, and a neutron energy- dependent decoupling reflector liner covering the interior surfaces of the thermal neutron exit port and surrounding all surfaces of the moderator block except the surface viewed by the thermal neutron exit port. (Official Gazette)

Spatio-temporal distribution and sources of Pb identified by stable isotopic ratios in sediments from the Yangtze River Estuary and adjacent areas.

PubMed

Chen, Bin; Liu, Jian; Hu, Limin; Liu, Ming; Wang, Liang; Zhang, Xilin; Fan, Dejiang

2017-02-15

To understand the spatio-temporal distribution and sources of Pb in the sediments of the Yangtze River Estuary and its adjacent areas, 25 surface sediments and 1 sediment core were collected from the study areas. The concentrations of Al and Pb of these sediments exhibit a decreasing trend from the nearshore towards the offshore, with higher concentrations in the coastal areas of the East China Sea (ECS) and southwest of Jeju Island. According to the stable isotopic ratios of Pb, in combination with the elemental ratios and clay mineral data, it is inferred that sedimentary Pb in the surface sediments of the coastal areas of the ECS may come primarily from the Yangtze River, while the Pb southwest of Jeju Island is probably derived from both the Yangtze and Yellow Rivers. The particulate Pb derived from the Yangtze River was possibly dispersed along two paths: the path southward along the coastline of the ECS and the path eastward associated with the Changjiang Diluted Water (CDW), which crosses the shelf of the ECS towards the area southeast of Jeju Island. Although the Yangtze River Basin witnessed rapid economic development during the period from the late 1970s to the middle 1990s, the influence of human activity on Pb concentration remained weak in the Yangtze River Estuary. Since the early 2000s, however, sedimentary Pb has been significantly increasing in the coastal mud areas of the ECS due to the increasing influence of human activity, such as the increase in atmospheric emission of anthropogenic Pb in China, construction of the Three Gorges Dam (TGD), and the construction of smaller dams in the upper reaches of the Yangtze River. Coal combustion and the smelting of non-ferrous metals are possible anthropogenic sources for the sedimentary Pb in the Yangtze River Estuary. Copyright © 2016. Published by Elsevier B.V.

CCD photometry of 1218+304 1219+28 and 1727+50: Point sources, associated nebulosity and broadband spectra

NASA Technical Reports Server (NTRS)

Weistrop, D.; Shaffer, D. B.; Mushotzky, R. F.; Reitsma, H. J.; Smith, B. A.

1981-01-01

Visual and far red surface photometry were obtained of two X-ray emitting BL Lacertae objects, 1218+304 (2A1219+305) and 1727+50 (Izw 187), as well as the highly variable object 1219+28 (ON 231, W Com). The intensity distribution for 1727+50 can be modeled using a central point source plus a de Vaucouleurs intensity law for an underlying galaxy. The broad band spectral energy distribution so derived is consistent with what is expected for an elliptical galaxy. The spectral index of the point source is alpha = 0.97. Additional VLBI and X-ray data are also reported for 1727+50. There is nebulosity associated with the recently discovered object 1218+304. No nebulosity is found associated with 1219+28. A comparison of the results with observations at X-ray and radio frequencies suggests that all the emission from 1727+50 and 1218+304 can be interpreted as due solely to direct synchrotron emission. If this is the case, the data further imply the existence of relativistic motion effects and continuous particle injection.

Earth observing system instrument pointing control modeling for polar orbiting platforms

NASA Technical Reports Server (NTRS)

Briggs, H. C.; Kia, T.; Mccabe, S. A.; Bell, C. E.

1987-01-01

An approach to instrument pointing control performance assessment for large multi-instrument platforms is described. First, instrument pointing requirements and reference platform control systems for the Eos Polar Platforms are reviewed. Performance modeling tools including NASTRAN models of two large platforms, a modal selection procedure utilizing a balanced realization method, and reduced order platform models with core and instrument pointing control loops added are then described. Time history simulations of instrument pointing and stability performance in response to commanded slewing of adjacent instruments demonstrates the limits of tolerable slew activity. Simplified models of rigid body responses are also developed for comparison. Instrument pointing control methods required in addition to the core platform control system to meet instrument pointing requirements are considered.

40 CFR 414.101 - Toxic pollutant effluent limitations and standards for direct discharge point sources that do not...

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources...(k)fluoranthene 47 19 Benzo(a)pyrene 48 20 Bis(2-ethylhexyl) phthalate 258 95 Carbon Tetrachloride... micrograms per liter. 2 Total Zinc for Rayon Fiber Manufacture that uses the viscose process and Acrylic...

40 CFR 414.101 - Toxic pollutant effluent limitations and standards for direct discharge point sources that do not...

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Direct Discharge Point Sources...(k)fluoranthene 47 19 Benzo(a)pyrene 48 20 Bis(2-ethylhexyl) phthalate 258 95 Carbon Tetrachloride... micrograms per liter. 2 Total Zinc for Rayon Fiber Manufacture that uses the viscose process and Acrylic...

Quantifying the errors due to the superposition of analytical deformation sources

NASA Astrophysics Data System (ADS)

Neuberg, J. W.; Pascal, K.

2012-04-01

The displacement field due to magma movement in the subsurface is often modelled using a Mogi point source or a dislocation Okada source embedded in a homogeneous elastic half-space. When the magmatic system cannot be modelled by a single source it is often represented by several sources, their respective deformation fields are superimposed. However, in such a case the assumption of homogeneity in the half-space is violated and the interaction between sources in an elastic medium is neglected. In this investigation we have quantified the effects of neglecting the interaction between sources on the surface deformation field. To do so, we calculated the vertical and horizontal displacements for models with adjacent sources and we tested them against the solutions of corresponding numerical 3D finite element models. We implemented several models combining spherical pressure sources and dislocation sources, varying the pressure or dislocation of the sources and their relative position. We also investigated three numerical methods to model a dike as a dislocation tensile source or as a pressurized tabular crack. We found that the discrepancies between simple superposition of the displacement field and a fully interacting numerical solution depend mostly on the source types and on their spacing. The errors induced when neglecting the source interaction are expected to vary greatly with the physical and geometrical parameters of the model. We demonstrated that for certain scenarios these discrepancies can be neglected (<5%) when the sources are separated by at least 4 radii for two combined Mogi sources and by at least 3 radii for juxtaposed Mogi and Okada sources

Adjacent-level arthroplasty following cervical fusion.

PubMed

Rajakumar, Deshpande V; Hari, Akshay; Krishna, Murali; Konar, Subhas; Sharma, Ankit

2017-02-01

OBJECTIVE Adjacent-level disc degeneration following cervical fusion has been well reported. This condition poses a major treatment dilemma when it becomes symptomatic. The potential application of cervical arthroplasty to preserve motion in the affected segment is not well documented, with few studies in the literature. The authors present their initial experience of analyzing clinical and radiological results in such patients who were treated with arthroplasty for new or persistent arm and/or neck symptoms related to neural compression due to adjacent-segment disease after anterior cervical discectomy and fusion (ACDF). METHODS During a 5-year period, 11 patients who had undergone ACDF anterior cervical discectomy and fusion (ACDF) and subsequently developed recurrent neck or arm pain related to adjacent-level cervical disc disease were treated with cervical arthroplasty at the authors' institution. A total of 15 devices were implanted (range of treated levels per patient: 1-3). Clinical evaluation was performed both before and after surgery, using a visual analog scale (VAS) for pain and the Neck Disability Index (NDI). Radiological outcomes were analyzed using pre- and postoperative flexion/extension lateral radiographs measuring Cobb angle (overall C2-7 sagittal alignment), functional spinal unit (FSU) angle, and range of motion (ROM). RESULTS There were no major perioperative complications or device-related failures. Statistically significant results, obtained in all cases, were reflected by an improvement in VAS scores for neck/arm pain and NDI scores for neck pain. Radiologically, statistically significant increases in the overall lordosis (as measured by Cobb angle) and ROM at the treated disc level were observed. Three patients were lost to follow-up within the first year after arthroplasty. In the remaining 8 cases, the duration of follow-up ranged from 1 to 3 years. None of these 8 patients required surgery for the same vertebral level during the follow

Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope

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

Achterberg, A.; Duvoort, M. R.; Heise, J.

2007-05-15

We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selectedmore » sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit {phi}{sup 0}=((E/1 TeV)){sup {gamma}}{center_dot}(d{phi}/dE) to a point source flux of muon and tau neutrino (detected as muons arising from taus) is {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}+{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=11.1x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}{sup 0}}/{phi}{sub {nu}{sub {tau}}+{nu}{sub {tau}}}{sup 0}=1 and assuming a spectral index {gamma}=2. It should be noticed that this is the first time we set upper limits to the flux of muon and tau neutrinos. In previous papers we provided muon neutrino upper limits only neglecting the sensitivity to a signal from tau neutrinos, which improves the limits by 10% to 16%. The value of the average upper limit presented in this work corresponds to twice the limit on the muon neutrino flux {phi}{sub {nu}{sub {mu}}+{nu}{sub {mu}}}{sup 0}=5.5x10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}. A stacking analysis for preselected active galactic nuclei and a search based on the angular separation of the events were also performed. We report the most stringent flux upper limits to date, including the results of a detailed assessment of systematic uncertainties.« less

Location identification for indoor instantaneous point contaminant source by probability-based inverse Computational Fluid Dynamics modeling.

PubMed

Liu, X; Zhai, Z

2008-02-01

Indoor pollutions jeopardize human health and welfare and may even cause serious morbidity and mortality under extreme conditions. To effectively control and improve indoor environment quality requires immediate interpretation of pollutant sensor readings and accurate identification of indoor pollution history and source characteristics (e.g. source location and release time). This procedure is complicated by non-uniform and dynamic contaminant indoor dispersion behaviors as well as diverse sensor network distributions. This paper introduces a probability concept based inverse modeling method that is able to identify the source location for an instantaneous point source placed in an enclosed environment with known source release time. The study presents the mathematical models that address three different sensing scenarios: sensors without concentration readings, sensors with spatial concentration readings, and sensors with temporal concentration readings. The paper demonstrates the inverse modeling method and algorithm with two case studies: air pollution in an office space and in an aircraft cabin. The predictions were successfully verified against the forward simulation settings, indicating good capability of the method in finding indoor pollutant sources. The research lays a solid ground for further study of the method for more complicated indoor contamination problems. The method developed can help track indoor contaminant source location with limited sensor outputs. This will ensure an effective and prompt execution of building control strategies and thus achieve a healthy and safe indoor environment. The method can also assist the design of optimal sensor networks.

Identification of the source of permanent glare from a three-piece IOL.

PubMed

Wolffe, M; Landry, R J; Alpar, J J

2007-08-01

To identify the source of unwanted glare images from a three-piece intraocular lens (IOL) implant following cataract surgery. The IOL and posterior capsule were examined under mydriatic and nonmydriatic conditions using direct focal illumination from a slit lamp biomicroscope. Direct focal illumination was undertaken with both a narrow beam (0.1 mm in width) and small spot (0.1 mm in diameter) to identify the points at which the glare images were stimulated. While observing the location of the beam with the slit lamp biomicroscope, the patient indicated when the glare images were stimulated. The nasal haptic insertion into the optic was identified as the source of temporal line images arising from lights such as headlamps from oncoming cars and street lamps. The adjacent edge of the IOL was also identified as the likely source of additional cob web-like light rays. The haptic insertions in three-piece IOLs may, under certain conditions, interfere with light entering the pupil and produce extraneous images. Large mesopic pupils and decentred IOLs are conditions that increase the likelihood of unwanted glare images.

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

49 CFR 214.107 - Working over or adjacent to water.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Working over or adjacent to water. 214.107 Section 214.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.107 Working over or adjacent to water. (a)...

HIREGS observations of the Galactic center and Galactic plane: Separation of the diffuse Galactic hard X-ray continuum from the point source spectra

NASA Technical Reports Server (NTRS)

Boggs, S. E.; Lin, R. P.; Coburn, W.; Feffer, P.; Pelling, R. M.; Schroeder, P.; Slassi-Sennou, S.

1997-01-01

The balloon-borne high resolution gamma ray and X-ray germanium spectrometer (HIREGS) was used to observe the Galactic center and two positions along the Galactic plane from Antarctica in January 1995. For its flight, the collimators were configured to measure the Galactic diffuse hard X-ray continuum between 20 and 200 keV by directly measuring the point source contributions to the wide field of view flux for subtraction. The hard X-ray spectra of GX 1+4 and GRO J1655-40 were measured with the diffuse continuum subtracted off. The analysis technique for source separation is discussed and the preliminary separated spectra for these point sources and the Galactic diffuse emission are presented.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Technical Reports Server (NTRS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-01-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L(sub x)) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (gamma), hardness ratios, and L(sub X), in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L(sub X),0.5-8.0 keV > 10(exp 42) erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known alpha OX-?L? (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the 'non-AGN locus' in alpha OX-?L? (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR (is) less than -20 and L(sub X),0.5-8.0 keV (is) greater than 10(exp 41) erg s-1 is 0.08+0.35 -0.01, somewhat higher than the 5% fraction in galaxy clusters.

Atmospheric measurement of point source fossil fuel CO2 emissions

NASA Astrophysics Data System (ADS)

Turnbull, J. C.; Keller, E. D.; Baisden, W. T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

2013-11-01

We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m a.g.l. We also determined the surface CO2ff content averaged over several weeks from the 14CO2 content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~1 week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14CO2 sampling strategies.

ASSESSING NON-POINT SOURCES OF NITROGEN TO SMALL STREAMS IN THE SOUTH FORK BROAD RIVER WATERSHED (GEORGIA, USA)

EPA Science Inventory

The National Land Cover Data (NLCD) is a land cover classification derived from Landsat Thematic Mapper satellite data collected in the early to mid-1990s. In this work, land use coverages calculated from the NLCD database are used to assess the impact of non-point sources on the...

Local point sources that affect ground-water quality in the East Meadow area, Long Island, New York

USGS Publications Warehouse

Heisig, Paul M.

1994-01-01

The extent and chemical characteristics of ground water affected by three local point sources--a stormwater basin, uncovered road-salt-storage piles, and an abandoned sewage-treatment plant--were delineated during a 3-year study of the chemical characteristics and migration of a body of reclaimed wastewater that was applied to the watertable aquifer during recharge experiments from October 1982 through January 1984 in East Meadow. The timing, magnitude, and chemical quality of recharge from these point sources is highly variable, and all sources have the potential to skew determinations of the quality of ambient ground-water and of the reclaimed-wastewater plume if they are not taken into account. Ground water affected by recharge from the stormwater basin is characterized by low concentrations of nitrate + nitrite (less than 5 mg/L [milligrams per liter] as N) and sulfate (less than 40 mg/L) and is almost entirely within the upper glacial aquifer. The plume derived from road-salt piles is narrow, has high concentrations of chloride (greater than 50 mg/L) and sodium (greater than 75 mg/L), and also is limited to the upper glacial aquifer. The sodium, in high concentrations, could react with aquifer material and exchange for sorbed cations such as calcium, potassium, and magnesium. Water affected by secondary-treated sewage from the abandoned treatment plant extends 152 feet below land surface into the upper part of the Magothy aquifer and longitudinally beyond the southern edge of the study area, 7,750 feet south of the recharge site. Ground water affected by secondary-treated sewage within the study area typically contains elevated concentrations of reactive chemical constituents, such as potassium and ammonium, and low concentrations of dissolved oxygen. Conservative or minimally reactive constituents such as chloride and sodium have been transported out of the study area in the upper glacial aquifer and the intermediate (transitional) zone but remain in the less

Search for Point Sources of Ultra-High-Energy Cosmic Rays above 4.0 × 1019 eV Using a Maximum Likelihood Ratio Test

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abu-Zayyad, T.; Amann, J. F.; Archbold, G.; Atkins, R.; Bellido, J. A.; Belov, K.; Belz, J. W.; Ben-Zvi, S. Y.; Bergman, D. R.; Boyer, J. H.; Burt, G. W.; Cao, Z.; Clay, R. W.; Connolly, B. M.; Dawson, B. R.; Deng, W.; Farrar, G. R.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G. A.; Hüntemeyer, P.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Knapp, B. C.; Loh, E. C.; Maestas, M. M.; Manago, N.; Mannel, E. J.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Sasaki, M.; Schnetzer, S. R.; Seman, M.; Simpson, K. M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Westerhoff, S.; Wiencke, L. R.; Zech, A.

2005-04-01

We present the results of a search for cosmic-ray point sources at energies in excess of 4.0×1019 eV in the combined data sets recorded by the Akeno Giant Air Shower Array and High Resolution Fly's Eye stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.

New approach for point pollution source identification in rivers based on the backward probability method.

PubMed

Wang, Jiabiao; Zhao, Jianshi; Lei, Xiaohui; Wang, Hao

2018-06-13

Pollution risk from the discharge of industrial waste or accidental spills during transportation poses a considerable threat to the security of rivers. The ability to quickly identify the pollution source is extremely important to enable emergency disposal of pollutants. This study proposes a new approach for point source identification of sudden water pollution in rivers, which aims to determine where (source location), when (release time) and how much pollutant (released mass) was introduced into the river. Based on the backward probability method (BPM) and the linear regression model (LR), the proposed LR-BPM converts the ill-posed problem of source identification into an optimization model, which is solved using a Differential Evolution Algorithm (DEA). The decoupled parameters of released mass are not dependent on prior information, which improves the identification efficiency. A hypothetical case study with a different number of pollution sources was conducted to test the proposed approach, and the largest relative errors for identified location, release time, and released mass in all tests were not greater than 10%. Uncertainty in the LR-BPM is mainly due to a problem with model equifinality, but averaging the results of repeated tests greatly reduces errors. Furthermore, increasing the gauging sections further improves identification results. A real-world case study examines the applicability of the LR-BPM in practice, where it is demonstrated to be more accurate and time-saving than two existing approaches, Bayesian-MCMC and basic DEA. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimation of point source fugitive emission rates from a single sensor time series: a conditionally-sampled Gaussian plume reconstruction

EPA Science Inventory

This paper presents a technique for determining the trace gas emission rate from a point source. The technique was tested using data from controlled methane release experiments and from measurement downwind of a natural gas production facility in Wyoming. Concentration measuremen...

Point-source helicity injection for ST plasma startup in Pegasus

NASA Astrophysics Data System (ADS)

Redd, A. J.; Battaglia, D. J.; Bongard, M. W.; Fonck, R. J.; Schlossberg, D. J.

2009-11-01

Plasma current guns are used as point-source DC helicity injectors for forming non-solenoidal tokamak plasmas in the Pegasus Toroidal Experiment. Discharges driven by this injection scheme have achieved Ip>= 100 kA using Iinj<= 4 kA. They form at the outboard midplane, transition to a tokamak-like equilibrium, and continue to grow inward as Ip increases due to helicity injection and outer- PF induction. The maximum Ip is determined by helicity balance (injection rate vs resistive dissipation) and a Taylor relaxation limit, in which Ip√ITF Iinj/w, where w is the radial thickness of the gun-driven edge. Preliminary experiments tentatively confirm these scalings with ITF, Iinj, and w, increasing confidence in this simple relaxation model. Adding solenoidal inductive drive during helicity injection can push Ip up to, but not beyond, the predicted relaxation limit, demonstrating that this is a hard performance limit. Present experiments are focused on increasing the injection voltage (i.e., helicity injection rate) and reducing w. Near-term goals are to further test scalings predicted by the simple relaxation model and to study in detail the observed bursty n=1 activity correlated with rapid increases in Ip.

Source of water to Lithia Springs in Hillsborough County, Florida

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

Hickey, J.J.; Coates, M.J.

1993-03-01

The source of water to Lithia Springs adjacent to the Alafia River in Hillsborough County, Florida has traditionally been hypothesized to be from the Upper Floridan aquifer. As a result, potential impacts from an adjacent public supply well field has been of interest since the well field began production in July, 1988. The discharge from Lithia Springs since March, 1984 has averaged about 3,600,000 cubic feet per day. Pumpage from the adjacent well field since July, 1988 has averaged about 2,500,000 cubic feet per day. A comparison between mean daily pumpage from the well field and mean daily discharge frommore » the springs showed no apparent association indicating that the Floridan aquifer may not be the source for the springs. Lithologic data suggested that the Upper Floridan aquifer was confined with no direct connection to the springs. This confining unit hypothesis was tested and accepted by pumping two wells close to the springs. The test consisted of pumping both wells for about 13 days at a combined rate that was about 40% of the average daily well field pumpage. No discernable test caused effects were observed on the springs or in an adjacent 115-foot deep well open to carbonate rock. Because of this, it was concluded that the Upper Floridan aquifer was not the source of water to Lithia Springs. Interpretation of available data suggested that the source of water to Lithia Springs was from the intermediate aquifer system located within solution riddled Early Miocene carbonate rocks of the lower Hawthorn Formation with maybe an important aquifer contribution from the Alafia River.« less

Early Verb Constructions in French: Adjacency on the Left Edge

ERIC Educational Resources Information Center

Veneziano, Edy; Clark, Eve V.

2016-01-01

Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects frst only to present tense forms (as in…

Adjacent bin stability evaluating for feature description

NASA Astrophysics Data System (ADS)

Nie, Dongdong; Ma, Qinyong

2018-04-01

Recent study improves descriptor performance by accumulating stability votes for all scale pairs to compose the local descriptor. We argue that the stability of a bin depends on the differences across adjacent pairs more than the differences across all scale pairs, and a new local descriptor is composed based on the hypothesis. A series of SIFT descriptors are extracted from multiple scales firstly. Then the difference value of the bin across adjacent scales is calculated, and the stability value of a bin is calculated based on it and accumulated to compose the final descriptor. The performance of the proposed method is evaluated with two popular matching datasets, and compared with other state-of-the-art works. Experimental results show that the proposed method performs satisfactorily.

Possible effects of free convection on fire behavior - laminar and turbulent line and point sources of heat

Treesearch

S. Scesa; F. M. Sauer

1954-01-01

The transfer theory is applied to the problem of atmospheric diffusion of momentum and heat induced by line and point sources of heat on the surface of the earth. In order that the validity of the approximations of the boundary layer theory be realized, the thickness of the layer in which the temperatures and velocities differ appreciably from the values at...

Compensatory immigration depends on adjacent population size and habitat quality but not on landscape connectivity.

PubMed

Turgeon, Katrine; Kramer, Donald L

2012-11-01

1. Populations experiencing localized mortality can recover in the short term by net movement of individuals from adjacent areas, a process called compensatory immigration or spillover. Little is known about the factors influencing the magnitude of compensatory immigration or its impact on source populations. Such information is important for understanding metapopulation dynamics, the use of protected areas for conservation, management of exploited populations and pest control. 2. Using two small, territorial damselfish species (Stegastes diencaeus and S. adustus) in their naturally fragmented habitat, we quantified compensatory immigration in response to localized mortality, assessed its impact on adjacent source populations and examined the importance of potential immigrants, habitat quality and landscape connectivity as limiting factors. On seven experimental sites, we repeatedly removed 15% of the initial population size until none remained and immigration ceased. 3. Immigrants replaced 16-72% of original residents in S. diencaeus and 0-69% in S. adustus. The proportion of the source population that immigrated into depleted areas varied from 9% to 61% in S. diencaeus and from 3% to 21% in S. adustus. In S. diencaeus, compensatory immigration was strongly affected by habitat quality, to a lesser extent by the abundance of potential immigrants and not by landscape connectivity. In S. adustus, immigration was strongly affected by the density of potential migrants and not by habitat quality and landscape connectivity. On two control sites, immigration in the absence of creation of vacancies was extremely rare. 4. Immigration occurred in response to localized mortality and was therefore compensatory. It was highly variable, sometimes producing substantial impacts on both depleted and source populations. The magnitude of compensatory immigration was influenced primarily by the availability of immigrants and by the potential improvement in territory quality that they

Exploring objective climate classification for the Himalayan arc and adjacent regions using gridded data sources

NASA Astrophysics Data System (ADS)

Forsythe, N.; Blenkinsop, S.; Fowler, H. J.

2015-05-01

A three-step climate classification was applied to a spatial domain covering the Himalayan arc and adjacent plains regions using input data from four global meteorological reanalyses. Input variables were selected based on an understanding of the climatic drivers of regional water resource variability and crop yields. Principal component analysis (PCA) of those variables and k-means clustering on the PCA outputs revealed a reanalysis ensemble consensus for eight macro-climate zones. Spatial statistics of input variables for each zone revealed consistent, distinct climatologies. This climate classification approach has potential for enhancing assessment of climatic influences on water resources and food security as well as for characterising the skill and bias of gridded data sets, both meteorological reanalyses and climate models, for reproducing subregional climatologies. Through their spatial descriptors (area, geographic centroid, elevation mean range), climate classifications also provide metrics, beyond simple changes in individual variables, with which to assess the magnitude of projected climate change. Such sophisticated metrics are of particular interest for regions, including mountainous areas, where natural and anthropogenic systems are expected to be sensitive to incremental climate shifts.

Anchoring historical sequences using a new source of astro-chronological tie-points

NASA Astrophysics Data System (ADS)

Dee, Michael W.; Pope, Benjamin J. S.

2016-08-01

The discovery of past spikes in atmospheric radiocarbon activity, caused by major solar energetic particle events, has opened up new possibilities for high-precision chronometry. The two spikes, or Miyake Events, have now been widely identified in tree-rings that grew in the years 775 and 994 CE. Furthermore, all other plant material that grew in these years would also have incorporated the anomalously high concentrations of radiocarbon. Crucially, some plant-based artefacts, such as papyrus documents, timber beams and linen garments, can also be allocated to specific positions within long, currently unfixed, historical sequences. Thus, Miyake Events represent a new source of tie-points that could provide the means for anchoring early chronologies to the absolute timescale. Here, we explore this possibility, outlining the most expeditious approaches, the current challenges and obstacles, and how they might best be overcome.

Objectifying the Adjacent and Opposite Angles: A Cultural Historical Analysis

ERIC Educational Resources Information Center

Daher, Wajeeh; Musallam, Nadera

2018-01-01

The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles'…

The Volpe Center GPS Adjacent Band Compatibility Program Plan : GPS Adjacent Band Compatibility Workshop, Volpe Center, Cambridge MA

DOT National Transportation Integrated Search

2014-09-18

Approach to DOT GPS Adjacent Band Compatibility Assessment. Identify forums and provide public outreach to make sure the progress and work are as open and transparent as possible. Develop an implementation plan that incorporates aspects from the DOT ...

How to COAAD Images. I. Optimal Source Detection and Photometry of Point Sources Using Ensembles of Images

NASA Astrophysics Data System (ADS)

Zackay, Barak; Ofek, Eran O.

2017-02-01

Stacks of digital astronomical images are combined in order to increase image depth. The variable seeing conditions, sky background, and transparency of ground-based observations make the coaddition process nontrivial. We present image coaddition methods that maximize the signal-to-noise ratio (S/N) and optimized for source detection and flux measurement. We show that for these purposes, the best way to combine images is to apply a matched filter to each image using its own point-spread function (PSF) and only then to sum the images with the appropriate weights. Methods that either match the filter after coaddition or perform PSF homogenization prior to coaddition will result in loss of sensitivity. We argue that our method provides an increase of between a few and 25% in the survey speed of deep ground-based imaging surveys compared with weighted coaddition techniques. We demonstrate this claim using simulated data as well as data from the Palomar Transient Factory data release 2. We present a variant of this coaddition method, which is optimal for PSF or aperture photometry. We also provide an analytic formula for calculating the S/N for PSF photometry on single or multiple observations. In the next paper in this series, we present a method for image coaddition in the limit of background-dominated noise, which is optimal for any statistical test or measurement on the constant-in-time image (e.g., source detection, shape or flux measurement, or star-galaxy separation), making the original data redundant. We provide an implementation of these algorithms in MATLAB.

Estimation of diffuse and point source microbial pollution in the ribble catchment discharging to bathing waters in the north west of England.

PubMed

Wither, A; Greaves, J; Dunhill, I; Wyer, M; Stapleton, C; Kay, D; Humphrey, N; Watkins, J; Francis, C; McDonald, A; Crowther, J

2005-01-01

Achieving compliance with the mandatory standards of the 1976 Bathing Water Directive (76/160/EEC) is required at all U.K. identified bathing waters. In recent years, the Fylde coast has been an area of significant investments in 'point source' control, which have not proven, in isolation, to satisfactorily achieve compliance with the mandatory, let alone the guide, levels of water quality in the Directive. The potential impact of riverine sources of pollution was first confirmed after a study in 1997. The completion of sewerage system enhancements offered the potential for the study of faecal indicator delivery from upstream sources comprising both point sources and diffuse agricultural sources. A research project to define these elements commenced in 2001. Initially, a desk study reported here, estimated the principal infrastructure contributions within the Ribble catchment. A second phase of this investigation has involved acquisition of empirical water quality and hydrological data from the catchment during the 2002 bathing season. These data have been used further to calibrate the 'budgets' and 'delivery' modelling and these data are still being analysed. This paper reports the initial desk study approach to faecal indicator budget estimation using available data from the sewerage infrastructure and catchment sources of faecal indicators.

Interim Significant Noncompliance Policy for Clean Water Act Violations Associated with CSOs, SSOs, CAFOs, and Storm Water Point Sources

EPA Pesticide Factsheets

This policy addresses significant noncompliance (SNC) violations associated with combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), concentrated animal feeding operations (CAFOs), and storm water point source discharges covered by the National Pollutant Discharge Elimination System (NPDES) program under the Clean Water Act (CWA).

VizieR Online Data Catalog: Rotation measures of radio point sources (Xu+, 2014)

NASA Astrophysics Data System (ADS)

Xu, J.; Han, J.-L.

2015-04-01

We compiled a catalog of Faraday rotation measures (RMs) for 4553 extragalactic radio point sources published in literature. These RMs were derived from multi-frequency polarization observations. The RM data are compared to those in the NRAO VLA Sky Survey (NVSS) RM catalog. We reveal a systematic uncertainty of about 10.0+/-1.5rad/m2 in the NVSS RM catalog. The Galactic foreground RM is calculated through a weighted averaging method by using the compiled RM catalog together with the NVSS RM catalog, with careful consideration of uncertainties in the RM data. The data from the catalog and the interface for the Galactic foreground RM calculations are publicly available on the webpage: http://zmtt.bao.ac.cn/RM/ . (2 data files).

33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Loma; San Diego Bay, San Diego, CA. 165.1102 Section 165.1102 Navigation and Navigable Waters COAST... Guard District § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA. (a) Location. The following area is a security zone: The water adjacent to the Naval Base Point Loma, San Diego...

33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Loma; San Diego Bay, San Diego, CA. 165.1102 Section 165.1102 Navigation and Navigable Waters COAST... Guard District § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA. (a) Location. The following area is a security zone: The water adjacent to the Naval Base Point Loma, San Diego...

33 CFR 165.1102 - Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Loma; San Diego Bay, San Diego, CA. 165.1102 Section 165.1102 Navigation and Navigable Waters COAST... Guard District § 165.1102 Security Zone; Naval Base Point Loma; San Diego Bay, San Diego, CA. (a) Location. The following area is a security zone: The water adjacent to the Naval Base Point Loma, San Diego...

The XMM-SERVS survey: new XMM-Newton point-source catalog for the XMM-LSS field

NASA Astrophysics Data System (ADS)

Chen, C.-T. J.; Brandt, W. N.; Luo, B.; Ranalli, P.; Yang, G.; Alexander, D. M.; Bauer, F. E.; Kelson, D. D.; Lacy, M.; Nyland, K.; Tozzi, P.; Vito, F.; Cirasuolo, M.; Gilli, R.; Jarvis, M. J.; Lehmer, B. D.; Paolillo, M.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tanaka, M.; Vaccari, M.; Vignali, C.; Xue, Y. Q.; Banerji, M.; Chow, K. E.; Häußler, B.; Norris, R. P.; Silverman, J. D.; Trump, J. R.

2018-04-01

We present an X-ray point-source catalog from the XMM-Large Scale Structure survey region (XMM-LSS), one of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields. We target the XMM-LSS region with 1.3 Ms of new XMM-Newton AO-15 observations, transforming the archival X-ray coverage in this region into a 5.3 deg2 contiguous field with uniform X-ray coverage totaling 2.7 Ms of flare-filtered exposure, with a 46 ks median PN exposure time. We provide an X-ray catalog of 5242 sources detected in the soft (0.5-2 keV), hard (2-10 keV), and/or full (0.5-10 keV) bands with a 1% expected spurious fraction determined from simulations. A total of 2381 new X-ray sources are detected compared to previous source catalogs in the same area. Our survey has flux limits of 1.7 × 10-15, 1.3 × 10-14, and 6.5 × 10-15 erg cm-2 s-1 over 90% of its area in the soft, hard, and full bands, respectively, which is comparable to those of the XMM-COSMOS survey. We identify multiwavelength counterpart candidates for 99.9% of the X-ray sources, of which 93% are considered as reliable based on their matching likelihood ratios. The reliabilities of these high-likelihood-ratio counterparts are further confirmed to be ≈97% reliable based on deep Chandra coverage over ≈5% of the XMM-LSS region. Results of multiwavelength identifications are also included in the source catalog, along with basic optical-to-infrared photometry and spectroscopic redshifts from publicly available surveys. We compute photometric redshifts for X-ray sources in 4.5 deg2 of our field where forced-aperture multi-band photometry is available; >70% of the X-ray sources in this subfield have either spectroscopic or high-quality photometric redshifts.

Ion source with corner cathode

NASA Technical Reports Server (NTRS)

Herrero, Federico A. (Inventor); Roman, Patrick A. (Inventor)

2012-01-01

An ion source may include first, second, and third electrodes. The first electrode may be a repeller having a V-shaped groove. The second electrode may be an electron emitter filament disposed adjacent the base of the V-shaped groove. The third electrode may be an anode that defines an enclosed volume with an aperture formed therein adjacent the electron emitter filament. A potential of the first electrode may be less than a potential of the second electrode, and the potential of the second electrode may be less than a potential of the third electrode. A fourth electrode that is disposed between the electron emitter filament and the anode may be used to produce a more collimated electron beam.

Point-source stochastic-method simulations of ground motions for the PEER NGA-East Project

USGS Publications Warehouse

Boore, David

2015-01-01

Ground-motions for the PEER NGA-East project were simulated using a point-source stochastic method. The simulated motions are provided for distances between of 0 and 1200 km, M from 4 to 8, and 25 ground-motion intensity measures: peak ground velocity (PGV), peak ground acceleration (PGA), and 5%-damped pseudoabsolute response spectral acceleration (PSA) for 23 periods ranging from 0.01 s to 10.0 s. Tables of motions are provided for each of six attenuation models. The attenuation-model-dependent stress parameters used in the stochastic-method simulations were derived from inversion of PSA data from eight earthquakes in eastern North America.

IceCube results from point-like source searches using 6 years of through-going muon data

NASA Astrophysics Data System (ADS)

Coenders, Stefan

2016-04-01

The IceCube Neutrino Observatory located at the geographic South Pole was designed to study and discover high energy neutrinos coming from both galactic and extra-galactic astrophysical sources. Track-like events induced by charged-current muon-neutrino interactions close to the IceCube detector give an angular resolution better than 1∘ above TeV energies. We present here the results of searches for point-like astrophysical neutrino sources on the full sky using 6 years of detector livetime, of which three years use the complete IceCube detector. Within 2000 days of detector livetime, IceCube is sensitive to a steady flux substantially below E2∂ϕ/∂E = 10-12 TeV cm-2 s-1 in the northern sky for neutrino energies above 10 TeV.

Gibbs Energy Modeling of Digenite and Adjacent Solid-State Phases

NASA Astrophysics Data System (ADS)

Waldner, Peter

2017-08-01

All sulfur potential and phase diagram data available in the literature for solid-state equilibria related to digenite have been assessed. Thorough thermodynamic analysis at 1 bar total pressure has been performed. A three-sublattice approach has been developed to model the Gibbs energy of digenite as a function of composition and temperature using the compound energy formalism. The Gibbs energies of the adjacent solid-state phases covelitte and high-temperature chalcocite are also modeled treating both sulfides as stoichiometric compounds. The novel model for digenite offers new interpretation of experimental data, may contribute from a thermodynamic point of view to the elucidation of the role of copper species within the crystal structure and allows extrapolation to composition regimes richer in copper than stoichiometric digenite Cu2S. Preliminary predictions into the ternary Cu-Fe-S system at 1273 K (1000 °C) using the Gibbs energy model of digenite for calculating its iron solubility are promising.

Adjacent-Categories Mokken Models for Rater-Mediated Assessments

PubMed Central

Wind, Stefanie A.

2016-01-01

Molenaar extended Mokken’s original probabilistic-nonparametric scaling models for use with polytomous data. These polytomous extensions of Mokken’s original scaling procedure have facilitated the use of Mokken scale analysis as an approach to exploring fundamental measurement properties across a variety of domains in which polytomous ratings are used, including rater-mediated educational assessments. Because their underlying item step response functions (i.e., category response functions) are defined using cumulative probabilities, polytomous Mokken models can be classified as cumulative models based on the classifications of polytomous item response theory models proposed by several scholars. In order to permit a closer conceptual alignment with educational performance assessments, this study presents an adjacent-categories variation on the polytomous monotone homogeneity and double monotonicity models. Data from a large-scale rater-mediated writing assessment are used to illustrate the adjacent-categories approach, and results are compared with the original formulations. Major findings suggest that the adjacent-categories models provide additional diagnostic information related to individual raters’ use of rating scale categories that is not observed under the original formulation. Implications are discussed in terms of methods for evaluating rating quality. PMID:29795916

Spatiotemporal Distribution, Sources, and Photobleaching Imprint of Dissolved Organic Matter in the Yangtze Estuary and Its Adjacent Sea Using Fluorescence and Parallel Factor Analysis

PubMed Central

Li, Penghui; Chen, Ling; Zhang, Wen; Huang, Qinghui

2015-01-01

To investigate the seasonal and interannual dynamics of dissolved organic matter (DOM) in the Yangtze Estuary, surface and bottom water samples in the Yangtze Estuary and its adjacent sea were collected and characterized using fluorescence excitation-emission matrices (EEMs) and parallel factor analysis (PARAFAC) in both dry and wet seasons in 2012 and 2013. Two protein-like components and three humic-like components were identified. Three humic-like components decreased linearly with increasing salinity (r>0.90, p<0.001), suggesting their distribution could primarily be controlled by physical mixing. By contrast, two protein-like components fell below the theoretical mixing line, largely due to microbial degradation and removal during mixing. Higher concentrations of humic-like components found in 2012 could be attributed to higher freshwater discharge relative to 2013. There was a lack of systematic patterns for three humic-like components between seasons and years, probably due to variations of other factors such as sources and characteristics. Highest concentrations of fluorescent components, observed in estuarine turbidity maximum (ETM) region, could be attributed to sediment resuspension and subsequent release of DOM, supported by higher concentrations of fluorescent components in bottom water than in surface water at two stations where sediments probably resuspended. Meanwhile, photobleaching could be reflected from the changes in the ratios between fluorescence intensity (Fmax) of humic-like components and chromophoric DOM (CDOM) absorption coefficient (a355) along the salinity gradient. This study demonstrates the abundance and composition of DOM in estuaries are controlled not only by hydrological conditions, but also by its sources, characteristics and related estuarine biogeochemical processes. PMID:26107640

Analysis of SO II point source emissions using NASA atmospheric infrared sounder data

NASA Astrophysics Data System (ADS)

Shen, Sylvia S.; Miller, David P.; Lewis, Paul E.

2007-04-01

Determining the extent to which large power plant emission sources interacting with atmospheric constituents affect the environment could play a significant role in future U.S. energy production policy. The effects on the environment caused by the interaction between power plant emissions and atmospheric constituents has not been investigated in depth due to the lack of calibrated spectral data on a suitable temporal and spatial scale. The availability of NASA's space-based Atmospheric Infrared Sounder (AIRS) data makes it possible to explore, and begin the first steps toward establishing, a correlation between known emission sources and environmental indicators. An exploratory study was conducted in which a time series of 26 cloud-free AIRS data containing two coal-fired power plants in northern New Mexico were selected, acquired, and analyzed for SO II emissions. A generic forward modeling process was also developed to derive an estimate of the expected AIRS pixel radiance containing the SO II emissions from the two power plants based on published combustion analysis data for coal and available power plant documentation. Analysis of the AIRS NEΔR calculated in this study and subsequent comparison with the radiance values for SO II calculated from the forward model provided essential information regarding the suitability and risk in the use of a modified AIRS configuration for monitoring anthropogenic point source emissions. The results of this study along with its conclusions and recommendations in conjunction with additional research collaboration in several specific topics will provide guidance for the development of the next generation infrared spectrometer system that NASA is considering building for environmental monitoring.

Statistical measurement of the gamma-ray source-count distribution as a function of energy

DOE PAGES

Zechlin, Hannes-S.; Cuoco, Alessandro; Donato, Fiorenza; ...

2016-07-29

Statistical properties of photon count maps have recently been proven as a new tool to study the composition of the gamma-ray sky with high precision. Here, we employ the 1-point probability distribution function of six years of Fermi-LAT data to measure the source-count distribution dN/dS and the diffuse components of the high-latitude gamma-ray sky as a function of energy. To that aim, we analyze the gamma-ray emission in five adjacent energy bands between 1 and 171 GeV. It is demonstrated that the source-count distribution as a function of flux is compatible with a broken power law up to energies of ~50 GeV. Furthermore, the index below the break is between 1.95 and 2.0. For higher energies, a simple power-law fits the data, with an index ofmore » $${2.2}_{-0.3}^{+0.7}$$ in the energy band between 50 and 171 GeV. Upper limits on further possible breaks as well as the angular power of unresolved sources are derived. We find that point-source populations probed by this method can explain $${83}_{-13}^{+7}$$% ($${81}_{-19}^{+52}$$%) of the extragalactic gamma-ray background between 1.04 and 1.99 GeV (50 and 171 GeV). Our method has excellent capabilities for constraining the gamma-ray luminosity function and the spectra of unresolved blazars.« less

Statistical measurement of the gamma-ray source-count distribution as a function of energy

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

Zechlin, Hannes-S.; Cuoco, Alessandro; Donato, Fiorenza

Statistical properties of photon count maps have recently been proven as a new tool to study the composition of the gamma-ray sky with high precision. Here, we employ the 1-point probability distribution function of six years of Fermi-LAT data to measure the source-count distribution dN/dS and the diffuse components of the high-latitude gamma-ray sky as a function of energy. To that aim, we analyze the gamma-ray emission in five adjacent energy bands between 1 and 171 GeV. It is demonstrated that the source-count distribution as a function of flux is compatible with a broken power law up to energies of ~50 GeV. Furthermore, the index below the break is between 1.95 and 2.0. For higher energies, a simple power-law fits the data, with an index ofmore » $${2.2}_{-0.3}^{+0.7}$$ in the energy band between 50 and 171 GeV. Upper limits on further possible breaks as well as the angular power of unresolved sources are derived. We find that point-source populations probed by this method can explain $${83}_{-13}^{+7}$$% ($${81}_{-19}^{+52}$$%) of the extragalactic gamma-ray background between 1.04 and 1.99 GeV (50 and 171 GeV). Our method has excellent capabilities for constraining the gamma-ray luminosity function and the spectra of unresolved blazars.« less

[L-THIA-based management design for controlling urban non-point source pollution].

PubMed

Guo, Qing-Hai; Yang, Liu; Ke-Ming, Ma

2007-11-01

L-THIA Model was used to simulate the amounts of NPS pollutants in 2 catchments of Sanjiao watershed (Sj1, Sj2) in Hanyang district, and the total simulated amount of NPS loads in Sj1 and Sj2 were 1.82 x 10(4) kg, 1.38 x 10(5) kg, respectively. Based on the theory of resource-sink" and interaction of pattern with process, a series of BMPs, including green roof, grassland, porous pavement, infiltration trench, vegetative filter strip and wet pond, were optimized, and effects of BMPs were simulated along the surface runoff pathway. The results show that total pollutants outputs entering Sj1 and Sj2 account for 14.65% and 6.57%, respectively. Combining L-THIA model and BMPs in series is a proper measure for non-point source pollution control and urban development planning at watershed or region scale.

Threshold voltage variation depending on single grain boundary and stored charges in an adjacent cell for vertical silicon–oxide–nitride–oxide–silicon NAND flash memory

NASA Astrophysics Data System (ADS)

Oh, Hyeongwan; Kim, Jiwon; Baek, Rock-Hyun; Lee, Jeong-Soo

2018-04-01

The effects of single grain boundary (SGB) position and stored electron charges in an adjacent cell in silicon–oxide–nitride–oxide–silicon (SONOS) structures on the variations of threshold voltage (V th) were investigated using technology computer-aided design (TCAD) simulation. As the bit line voltage increases, the SGB position causing the maximum V th variation was shifted from the center to the source side in the channel, owing to the drain-induced grain barrier lowering effect. When the SGB is located in the spacer region, the potential interaction from both the SGB and the stored electron charges in the adjacent cell becomes significant and thus resulting in larger V th variation. In contrast, when the SGB is located at the center of the channel, the peak position of potential barrier is shifted to the center, so that the influence of the adjacent cell is diminished. As the gate length is scaled down to 20 nm, the influence of stored charges in adjacent cells becomes significant, resulting in larger V th variations.

Internal calibration on adjacent samples (InCAS) with Fourier transform mass spectrometry.

PubMed

O'Connor, P B; Costello, C E

2000-12-15

Using matrix-assisted laser desorption/ionization (MAL DI) on a trapped ion mass spectrometer such as a Fourier transform mass spectrometer (FTMS) allows accumulation of ions in the cell from multiple laser shots prior to detection. If ions from separate MALDI samples are accumulated simultaneously in the cell, ions from one sample can be used to calibrate ions from the other sample. Since the ions are detected simultaneously in the cell, this is, in effect, internal calibration, but there are no selective desorption effects in the MALDI source. This method of internal calibration with adjacent samples is demonstrated here on cesium iodide clusters, peptides, oligosaccharides, poly(propylene glycol), and fullerenes and provides typical FTMS internal calibration mass accuracy of < 1 ppm.

Detection of spatial fluctuations of non-point source fecal pollution in coral reef surrounding waters in southwestern Puerto Rico using PCR-based assays.

PubMed

Bonkosky, M; Hernández-Delgado, E A; Sandoz, B; Robledo, I E; Norat-Ramírez, J; Mattei, H

2009-01-01

Human fecal contamination of coral reefs is a major cause of concern. Conventional methods used to monitor microbial water quality cannot be used to discriminate between different fecal pollution sources. Fecal coliforms, enterococci, and human-specific Bacteroides (HF183, HF134), general Bacteroides-Prevotella (GB32), and Clostridium coccoides group (CP) 16S rDNA PCR assays were used to test for the presence of non-point source fecal contamination across the southwestern Puerto Rico shelf. Inshore waters were highly turbid, consistently receiving fecal pollution from variable sources, and showing the highest frequency of positive molecular marker signals. Signals were also detected at offshore waters in compliance with existing microbiological quality regulations. Phylogenetic analysis showed that most isolates were of human fecal origin. The geographic extent of non-point source fecal pollution was large and impacted extensive coral reef systems. This could have deleterious long-term impacts on public health, local fisheries and in tourism potential if not adequately addressed.

Electrode configuration for extreme-UV electrical discharge source

DOEpatents

Spence, Paul Andrew; Fornaciari, Neal Robert; Chang, Jim Jihchyun

2002-01-01

It has been demonstrated that debris generation within an electric capillary discharge source, for generating extreme ultraviolet and soft x-ray, is dependent on the magnitude and profile of the electric field that is established along the surfaces of the electrodes. An electrode shape that results in uniform electric field strength along its surface has been developed to minimize sputtering and debris generation. The electric discharge plasma source includes: (a) a body that defines a circular capillary bore that has a proximal end and a distal end; (b) a back electrode positioned around and adjacent to the distal end of the capillary bore wherein the back electrode has a channel that is in communication with the distal end and that is defined by a non-uniform inner surface which exhibits a first region which is convex, a second region which is concave, and a third region which is convex wherein the regions are viewed outwardly from the inner surface of the channel that is adjacent the distal end of the capillary bore so that the first region is closest to the distal end; (c) a front electrode positioned around and adjacent to the proximal end of the capillary bore wherein the front electrode has an opening that is communication with the proximal end and that is defined by a non-uniform inner surface which exhibits a first region which is convex, a second region which is substantially linear, and third region which is convex wherein the regions are viewed outwardly from the inner surface of the opening that is adjacent the proximal end of the capillary bore so that the first region is closest to the proximal end; and (d) a source of electric potential that is connected across the front and back electrodes.

COASTING ARC ION SOURCE

DOEpatents

Foster, J.S. Jr.

1957-09-10

An improved ion source is described and in particular a source in which the ions are efficiently removed. The plasma is generated in a tubular amode structure by the oscillation of electrons in an axial magnetic field, as in the Phillips Ion Gage. The novel aspect of the source is the expansion of the plasma as it leaves the anode structure, so as to reduce the ion density at the axis of the anode and present a uniform area of plasma to an extraction grid. The structure utilized in the present patent to expand the plasma comprises flange members of high permeability at the exitgrid end of the amode to diverge the magnetic field adjacent the exit.

Growth and decline of shoreline industry in Sydney estuary (Australia) and influence on adjacent estuarine sediments.

PubMed

Birch, G F; Lean, J; Gunns, T

2015-06-01

Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.

Indentations and Starting Points in Traveling Sales Tour Problems: Implications for Theory

ERIC Educational Resources Information Center

MacGregor, James N.

2012-01-01

A complete, non-trivial, traveling sales tour problem contains at least one "indentation", where nodes in the interior of the point set are connected between two adjacent nodes on the boundary. Early research reported that human tours exhibited fewer such indentations than expected. A subsequent explanation proposed that this was because…

Point-source and diffuse high-energy neutrino emission from Type IIn supernovae

NASA Astrophysics Data System (ADS)

Petropoulou, M.; Coenders, S.; Vasilopoulos, G.; Kamble, A.; Sironi, L.

2017-09-01

Type IIn supernovae (SNe), a rare subclass of core collapse SNe, explode in dense circumstellar media that have been modified by the SNe progenitors at their last evolutionary stages. The interaction of the freely expanding SN ejecta with the circumstellar medium gives rise to a shock wave propagating in the dense SN environment, which may accelerate protons to multi-PeV energies. Inelastic proton-proton collisions between the shock-accelerated protons and those of the circumstellar medium lead to multimessenger signatures. Here, we evaluate the possible neutrino signal of Type IIn SNe and compare with IceCube observations. We employ a Monte Carlo method for the calculation of the diffuse neutrino emission from the SN IIn class to account for the spread in their properties. The cumulative neutrino emission is found to be ˜10 per cent of the observed IceCube neutrino flux above 60 TeV. Type IIn SNe would be the dominant component of the diffuse astrophysical flux, only if 4 per cent of all core collapse SNe were of this type and 20-30 per cent of the shock energy was channeled to accelerated protons. Lower values of the acceleration efficiency are accessible by the observation of a single Type IIn SN as a neutrino point source with IceCube using up-going muon neutrinos. Such an identification is possible in the first year following the SN shock breakout for sources within 20 Mpc.

Mapping the scientific research on non-point source pollution: a bibliometric analysis.

PubMed

Yang, Beibei; Huang, Kai; Sun, Dezhi; Zhang, Yue

2017-02-01

A bibliometric analysis was conducted to examine the progress and future research trends of non-point source (NPS) pollution during the years 1991-2015 based on the Science Citation Index Expanded (SCI-Expanded) of Web of Science (WoS). The publications referencing NPS pollution were analyzed including the following aspects: document type, publication language, publication output and characteristics, subject category, source journal, distribution of country and institution, author keywords, etc. The results indicate that the study of NPS pollution demonstrated a sharply increasing trend since 1991. Article and English were the most commonly used document type and language. Environmental sciences and ecology, water resources, and engineering were the top three subject categories. Water science and technology ranked first in distribution of journal, followed by Science of the total environment and Environmental Monitoring and Assessment. The USA took a leading position in both quantity and quality, playing an important role in the research field of NPS pollution, followed by the UK and China. The most productive institution was the Chinese Academy of Sciences (Chinese Acad Sci), followed by Beijing Normal University and US Department of Agriculture's Agricultural Research Service (USDA ARS). The analysis of author keywords indicates that the major hotspots of NPS pollution from 1991 to 2015 contained "water," "model," "agriculture," "nitrogen," "phosphorus," etc. The results provide a comprehensive understanding of NPS pollution research and help readers to establish the future research directions.

Improvement of correlation-based centroiding methods for point source Shack-Hartmann wavefront sensor

NASA Astrophysics Data System (ADS)

Li, Xuxu; Li, Xinyang; wang, Caixia

2018-03-01

This paper proposes an efficient approach to decrease the computational costs of correlation-based centroiding methods used for point source Shack-Hartmann wavefront sensors. Four typical similarity functions have been compared, i.e. the absolute difference function (ADF), ADF square (ADF2), square difference function (SDF), and cross-correlation function (CCF) using the Gaussian spot model. By combining them with fast search algorithms, such as three-step search (TSS), two-dimensional logarithmic search (TDL), cross search (CS), and orthogonal search (OS), computational costs can be reduced drastically without affecting the accuracy of centroid detection. Specifically, OS reduces calculation consumption by 90%. A comprehensive simulation indicates that CCF exhibits a better performance than other functions under various light-level conditions. Besides, the effectiveness of fast search algorithms has been verified.

Simulation of agricultural non-point source pollution in Xichuan by using SWAT model

NASA Astrophysics Data System (ADS)

Xing, Linan; Zuo, Jiane; Liu, Fenglin; Zhang, Xiaohui; Cao, Qiguang

2018-02-01

This paper evaluated the applicability of using SWAT to access agricultural non-point source pollution in Xichuan area. In order to build the model, DEM, soil sort and land use map, climate monitoring data were collected as basic database. The SWAT model was calibrated and validated for the SWAT was carried out using streamflow, suspended solids, total phosphorus and total nitrogen records from 2009 to 2011. Errors, coefficient of determination and Nash-Sutcliffe coefficient were considered to evaluate the applicability. The coefficient of determination were 0.96, 0.66, 0.55 and 0.66 for streamflow, SS, TN, and TP, respectively. Nash-Sutcliffe coefficient were 0.93, 0.5, 0.52 and 0.63, respectively. The results all meet the requirements. It suggested that the SWAT model can simulate the study area.

Thermal structure of Sikhote Alin and adjacent areas based on spectral analysis of the anomalous magnetic field